Title of Invention

"CONDUCTIVE PARTICLE, VISIBLE LIGHT TRANSMISSIVE PARTICLE DISPERSED CONDUCTOR, METHOD FOR PRODUCING SAME, TRANSPARENT CONDUCTIVE THIN FILM, METHOD FOR PRODUCING SAME, TRANSPARENT CONDUCTIVE ARTICLE USING SAME, AND INFRARED SHIELDING ARTICLE"

Abstract A transparent electroconductive film composed of a composite oxide expressed by the general formula MEAGW(1-G)OJ (where M is one or more elements selected from Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn; A is one or more elements selected from Mo, Nb, Ta, Mn, V, Re, Pt, Pd, and Ti; W is tungsten; O is oxygen; 0<E&#8804;1.2; 0<G<1; and 2&#8804;J&#8804;3) and having one or more structures selected from cubic, tetragonal, and hexagonal tungsten bronze structures, characterized in that the maximum transmittance in the region of 400 nm or greater to 780 nm or less ranges from 10% or greater to less than 92%; and the surface resistance of the film is 1.0x1010 &#937;/square or less.
Full Text DESCRIPTION
ELECTROCONDUCTIVE PARTICLE, VISIBLE LIGHT TRANSMITTING
PARTICLE-DISPERSED ELECTRICAL CONDUCTOR AND MANUFACTURING
METHOD THEREOF, TRANSPARENT ELECTROCONDUCTIVE THIN FILM AND
MANUFACTURING METHOD THEREOF, TRANSPARENT ELECTROCONDUCTIVE
ARTICLE THAT USES THE SAME, AND INFRARED-SHIELDING ARTICLE
TECHNICAL FIELD
[0001]
The present invention relates to an infrared-shielding
nanoparticle dispersion having dispersed infrared-shielding
nanoparticles that contain composite oxide nanoparticles
having characteristics in which light in the visible region is
transmitted and light in the near infrared region is absorbed,
to an infrared-shielding body manufactured using the infraredshielding
nanoparticle dispersion, to a method for
manufacturing infrared-shielding nanoparticles for
manufacturing infrared-shielding nanoparticles that are used
in the infrared-shielding nanoparticle dispersion, and to
infrared-shielding nanoparticles manufactured using the method
for manufacturing the infrared-shielding nanoparticles.
The present invention also relates to a visible light
transmitting particle-dispersed electrical conductor that uses
the electroconductive particles composed of tungsten oxide
and/or a composite tungsten oxide, a visible-lighttransmitting
electroconductive article formed from the visible
light transmitting particle-dispersed electrical conductor.
electroconductive particles used in the visible light
transmitting particle-dispersed electrical conductor and the
visible-light-transmitting electroconductive article, and a
method for manufacturing the above.
The present invention further relates to a transparent
electroconductive film that transmits visible light and a
method for manufacturing the film; to a transparent
electroconductive article that uses the transparent
electroconductive film; and to a visible-light-transmitting
infrared-shielding article that uses the transparent
electroconductive film.
BACKGROUND ART
[0002]
Patent document 1 proposes, as a light-blocking material
used in window materials and the like, a black-pigmentcontaining
light-blocking film, which includes carbon black,
titanium black, and other inorganic pigments having lightabsorbing
characteristics that range from the visible light
region to the near infrared region; and aniline black and
other organic pigments having strong light-absorbing
characteristics for light solely in the visible light region.
Patent document 2 proposes a half-mirror light-blocking
material on which aluminum or another metal has been deposited.
[0003]
In patent document 3, a heat-blocking glass is proposed
in which a composite tungsten oxide film is disposed as a
first layer on a transparent glass substrate, with the film
containing at least one type of metal ion selected from the
group consisting of Group Ilia, Group IVa, Group Vb, Group VIb,
and Group Vllb in the periodic table of the elements; a
transparent dielectric film as a second layer is disposed on
the first layer; a composite tungsten oxide film is disposed
as a third layer on the second layer, with the film containing
at least one type of metal ion selected from the group
consisting of Group Ilia, Group IVa, Group Vb, Group VIb, and
Group Vllb in the periodic table of the elements; and the
index of refraction of the transparent dielectric film of the
second layer is less than the index of refraction of the
composite tungsten oxide film of the first and third layers.
The heat-blocking glass can therefore be advantageously used
in locations that require high visible-light transmittance and
good heat-blocking performance.
[0004]
In patent document 4, a heat-blocking glass is proposed
in which a first dielectric film is disposed as a first layer
on a transparent glass substrate, a tungsten oxide film as
second layer is disposed on the first layer, and a second
dielectric film as a third layer is disposed on the second
layer, using the same method as that in patent document 3.
[0005]
In patent document 5, a heat-blocking glass is proposed
in which a composite tungsten oxide containing the same metal
element as that in patent document 3 is disposed as a first
layer on a transparent glass substrate, and a transparent
dielectric film as second layer is disposed on the first layer,
using the same method as that in patent document 3.
[0006]
In patent document 6, a sunlight-controlling glass sheet
having sunlight-shielding characteristics is proposed in which
a metal oxide film is formed by CVD or spraying, and the film
is thermally decomposed at about 250°C. The metal oxide film
has one more components selected from the group consisting of
tungsten trioxide (WO3), molybdenum trioxide (MoO3), niobium
pentoxide (Nb2O5), tantalum pentoxide (Ta2O5), vanadium
pentoxide (V2O5), and vanadium dioxide (VO2), and contains
hydrogen, lithium, sodium, potassium, or other additive
materials.
10007]
In Patent document 7, a solar light-varying/dimming,
heat-blocking material is proposed that can undergo rapid
coloration/decoloration reactions when exposed to the solar
light and that, when colored, has an absorption peak at 1250
nra in the near-infrared region, resulting in the ability to
block solar light in the near-infrared region. This material
uses a tungsten oxide obtained by hydrolysis of tungstic acid.
An organic polymer having a specific structure and referred to
as polyvinylpyrrolldone is added to the tungsten oxide. When
the material is exposed to the solar light, UV rays in the
solar light are absorbed by the tungsten oxide, and excited
electrons and holes are generated. A small dose of UV
irradiation can markedly increase the amount of pentavalent
tungsten that is generated, which accelerates the coloring
reaction, and the material shields light as the color density
of increases. The pentavalent tungsten is thereby extremely
rapidly oxidized to hexavalent tungsten and the discoloring
reaction is accelerated.
[0008]
In patent document 8, the inventors have proposed a way
to obtain a powder composed of tungsten trloxide, a hydrate of
tungsten trioxide, or a mixture of tungsten trioxide and a
hydrate of tungsten trioxide by dissolving tungsten
hexachloride in an alcohol and directly evaporating the
solvent, or by heating and refluxing the mixture and then
evaporating the solvent, and thereafter heating [the residue]
at 100°C to 500°C. The inventors have also proposed that
nanoparticles of such a tungsten oxide can be used to obtain
an electrochromic element, and that a multilayered laminate
can be formed. When protons are Introduced into the film, the
optical characteristics of the film can be changed.
[0009]
In recent years, the need for transparent electrodes has
Increased in association with the development of various types
of display elements. Since numerous free electrons are
retained in the material of transparent electrodes and the
electrical conductivity is high, ITO (Indium-Tin-Oxide)
obtained by doping indium oxide with several molar percent of
tin is mainly used (see patent document 9). In2O3/ which is an
ITO matrix, is an oxide semiconductor, and carrier electrons
are supplied from oxygen defects contained in the crystals.
The substance is therefore a transparent electroconductive
substance. It is believed that when Sn is added to In203, the
amount of carrier electrons is greatly increased and high
electrical conductivity is exhibited. The transparent
electroconductive film related to the particle dispersion of
the present invention is currently used in the transparent
electrodes of display elements, plasma display elements, solar
cells, and the like, as well as in infrared-absorbing and
reflecting films, defogglng films, electromagnetism-shielding
films, and other films.
[0010]
Recent display apparatuses are in a downward trend in
relation to costs. There is need to improve the performance
of transparent electrodes, particularly to reduce the sheet
resistance and improve the visible-light transmittance in
order to obtain a high quality display element that is devoid
of display defects, and it is extremely important to reduce
the cost of the transparent electrode itself. Improvements
are being made in ITO deposition technology, sputtering
targets, and other aspects. Therefore, improvements are being
made in the physical properties of transparent
electroconductive films, and progress is being made in
reducing costs. However, there is a limit to reducing the
costs of ITO, and it has become difficult to respond to the
recent wider range of needs.
[0011]
On the other hand, known as a particle-dispersed
transparent electroconductive film is a fine particle film
(see patent document 10) in which an aqueous solution (A)
containing silver bromide and palladium salt, and an aqueous
solution (B) containing citric acid ions and ferrous ions are
mixed in an atmosphere essentially devoid of oxygen to
precipitate Ag-Pd fine particles, and a coating solution
containing the Ag-Pd fine particles in water and/or an organic
solvent are applied to a base material. Also known is a
transparent electroconductive film (see patent document 11) in
which secondary particles having an average secondary particle
diameter of 120 to 200 nm are formed from ITO particles having
an average primary particle diameter of 10 to 60 nm, and an
ink composition in which the secondary particles are dispersed
is used to form the film.
[0012]
In patent document 12, a method is proposed for producing
various tungsten bronzes expressed by the formula MXWO3 (where
M is an alkali metal, an alkaline-earth metal, a rare earth
element, or another metal element, and 0 uses an ammonium meta tungstate and various water-soluble
metal salts as starting materials and involves heating the dry
solids obtained from a mixed aqueous solution of the starting
materials at about 300 to 700°C, and supplying a gaseous
hydrogen containing an inert gas (added amount: about 50 vol%
or greater) or water vapor (added amount 15 vol% or less) to
the solid material. Also proposed is a method in which the
same operation is performed on the carrier to manufacture
various compound materials coated with tungsten bronze.
However, the tungsten bronzes are intended as solid materials
to be used in the electrode catalyst material of fuel cells
and the like, and no consideration is given to transparency
and electrical conductivity.
[0013]
On the other hand, transparent electroconductlve films
are used in the transparent electrodes of liquid crystal
display elements, plasma display elements, solar cells, and
the like, as well as in Infrared-absorbing and reflecting
films, defogglng films, electromagnetism-shielding films, and
other films.
[0014]
Liquid crystal display apparatuses in particular are
actively being adopted in recent years in personal computers,
word processors, and other OA equipment, leading to greater
demand for transparent electrodes. Transparent electrodes for
liquid crystal display elements have numerous conduction
electrons (free electrons) in the material, electrical
conductivity is high, and patterning by etching is relatively
simple. Therefore, ITO (Indium-Tin-Oxide) obtained by doping
indium oxide with several molar percent of tin is mainly used
(see patent documents 13 and 14). In2O3, which is an ITO
matrix, is an oxide semiconductor, and carrier electrons are
supplied from oxygen defects contained in the crystals. It is
believed that when Sn is added to In2O3/ the amount of carrier
electrons is greatly increased and high electrical
conductivity is exhibited.
[0015]
In patent document 14, a high-transmittance transparent
electroconductive film is proposed in which an In oxide is
used as the main component, Ge is added, and the visible-light
transmlttance is 90% or greater.
[0016]
In patent document 16, a transparent electroconductive
film is proposed that exhibits good resistivity and greater
visible-light transmlttance than ITO. The film is composed of
a composite oxide which has a defect-fluorite crystal
structure and whose three main constituent elements are indium
(In), antimony (Sb), and oxygen (O). The film is a
transparent electroconductive film expressed by the general
formula In3Sbi-xO7.fi (which satisfies the ranges -0.2 £ X £ 0.2
and -0.5 a; b * 0.5) and doped, in a ratio of 0.1 to 20 at%,
with at least one element selected from the high-valence metal
elements Sn. Si, Ge, Ti, Zr. Pb, Cr, Mo, W, Te, V, Nb, Ta, Bi,
As, and Ce, and from the halogen elements F, Br, and I. The
film is subjected to reduction annealing to generate oxygen
holes, and carrier ions are thereby injected.
[0017]
[Patent Document 1]
[Patent Document 2]
[Patent Document 3]
[Patent Document 4]
[Patent Document 5]
[Patent Document 6]
[Patent Document 7]
[Patent Document 8]
[Patent Document 9]
[Patent Document 10]
[Patent Document 11]
[Patent Document 12]
[Patent Document 13]
[Patent Document 14]
[Patent Document 15]
JP-A 2003-29314
JP-A 9-107815
JP-A 8-59300
JP-A 8-12378
JP-A 8-283044
JP-A 2000-119045
JP-A 9-127559
JP-A 2003-121884
JP-A 2003-249125
JP-A 2000-90737
JP-A 2001-279137
JP-A 2004-026554
JP-A 2003-249125
JP-A 11-322333
JP-A 11-302017
JP-[Patent Document 16] A 8-73223
[DISCLOSURE OF THE INVENTION]
[PRIOR-ART PROBLEMS]
[0018]
The black pigment described in patent document 1 has
considerable light absorbing characteristics in the visible
region, and when the pigment is used in a window material or
the like, the window material tends to have dark colors, and
•*
therefore the application is limited.
A window material or the like to which the metaldeposited
film described in patent document 2 has been applied
has a half-mirror appearance, and such a half-mirror tends to
reflect brightly, which is a problem from the standpoint of
aesthetics.
[0019]
The heat-blocking materials described in patent documents
3 to 5 are mainly manufactured using sputtering, vapor
deposition, ion-plating, chemical vapor deposition (CVD), and
other dry vacuum deposition methods. For this reason, large
manufacturing apparatuses are required and costs are increased.
Also, the base materials used for these heat-blocking
materials are exposed to high-temperature plasma and require
heating after film deposition. Thus, when films and other
resin materials are used as base materials, facilities and
film deposition conditions must be separately considered.
[0020]
In the case of the sunlight-controlling glass sheet
described in patent document 6, the starting materials are
formed as a coating on glass by the joint use of thermal
decomposition and CVD or spraying, but since the starting
material precursors are costly, thermally decompose at high
temperature, and have other drawbacks, the film deposition
conditions must be separately considered when a film or
another resin is used as the base material.
[0021]
The solar light-varying/dimming, heat-blocking material
and electrochromic element proposed in patent documents 7 and
8 have a complicated film structure because the color tone of
the material is varied using UV rays or electrical potential
n
difference, and application to fields in which color tone
changes are not desired is difficult.
[0022]
The ITO electroconductive film described in patent
document 9 is an expensive film because iridium is used, and
there is a commercial demand for an inexpensive transparent
electroconductive thin film.
The noble metal particles described in patent document 10,
and the ITO particles described in patent document 11 can be
deposited by coating, and a bulky apparatus is therefore not
required. Deposition costs can be reduced, but the particles
themselves are expensive and lack wide applicability.
[0023]
The present invention was contrived in order to solve
such problems, and an object of this invention is to provide
an infrared-shielding nanoparticle dispersion that
sufficiently transmits light in the visible region, has lightshielding
characteristics in the near-infrared region, and
does not require the use of a bulky manufacturing apparatus
when the film is formed on the base material; to provide an
infrared-shielding body manufactured using the infraredshielding
nanoparticle dispersion; to provide a method for
manufacturing infrared-shielding nanoparticles used in the
infrared-shielding nanoparticle dispersion; and to provide
Infrared-shielding nanoparticles manufactured using the method
for manufacturing the infrared-shielding nanoparticles.
Another object is to provide an infrared-shielding body of
high visible transmittance using a transparent and
electroconductive body.
[0024]
The ITO electroconductive film described in patent
documents 9 and 12 are expensive films because iridium is used,
and there is a commercial demand for an inexpensive
transparent electroconductlve thin film.
The noble metal particles described in patent document 10
and the ITO particles described in patent document 11 can be
deposited by coating, and a bulky apparatus is therefore not
required. Deposition costs can be reduced, but the particles
themselves are expensive and lack wide applicability.
[0025]
The present invention was contrived in view of the abovedescribed
situation, and an object of the present Invention is
to provide an Inexpensive visible light transmitting particledispersed
electrical conductor that has excellent electrical
conductivity and visible light-transmission characteristics.
Another object of the present invention is to provide
electroconductive particles used in the visible light
transmitting particle-dispersed electrical conductor described
above.
Yet another object of the present invention is to provide
a visible-light-transmitting electroconductive article that
uses an inexpensive visible light transmitting particledispersed
electrical conductor having excellent electrical
conductivity and visible light-transmission characteristics.
Still another object of the present invention is to
provide an electroconductive particle manufacturing method
wherein a simple technique can be used to manufacture
electroconductive particles that are used to obtain an
inexpensive visible light transmitting particle-dispersed
electrical conductor that has excellent electrical
conductivity and visible light-transmission characteristics.
[0026]
The ITO electroconductive film described in patent
documents 12 and 13, and the electroconductive film described
in patent documents 14 and 15, in which In oxide is the
primary component, have excellent visible-light transmittance
and film surface resistance (sheet resistance), but these are
expensive films because iridium is used, and there is a
commercial demand for an inexpensive transparent
electroconductive film.
[0027]
The present invention was contrived in view of the abovedescribed
situation, and an object of this invention is to
provide an inexpensive transparent electroconductive film that
has excellent electrical conductivity and visible lighttransmission
characteristics.
Another object of the present invention is to provide a
transparent electroconductive film manufacturing method for
manufacturing in a simple manner an inexpensive transparent
electroconductive film having excellent electrical
conductivity and visible light-transmission characteristics.
Yet another object of the present invention is to provide
a transparent electroconductive article that uses an
inexpensive transparent electroconductive film having
excellent electrical conductivity and visible lighttransmission
characteristics.
Still another object of the present invention is to
provide a visible-light-transmitting Infrared-shielding
article that uses an Inexpensive transparent electroconductive
film having excellent electrical conductivity and visible
light-transmission characteristics.
[MEANS OF SOLVING THE PROBLEMS]
[0028]
Tungsten trioxide is a wide-bandgap oxide, absorbs very
little visible light, does not contain free electrons
(conduction electrons) in the structure, and therefore does
not exhibit electrical conductivity. Tungsten trioxide having
somewhat reduced oxygen, and so-called tungsten bronze
obtained by adding Na or other electropositive elements to
tungsten trioxide. are known to generate free electrons and to
have electrical conductivity. It is acknowledged that
tungsten trioxide having somewhat reduced oxygen, and tungsten
bronze obtained by adding Na or other electropositive elements
to tungsten trioxide, absorb visible light. Therefore, these
products are not used as particle-dispersed transparent
electroconductive materials.
[0029]
The inventors discovered that it is possible to form a
visible-light-transmitting transparent electroconductive film
because the above-described tungsten trioxide having somewhat
reduced oxygen, and tungsten bronze obtained by adding Na or
other electropositive elements to tungsten trioxide, have
strong absorbency of light having a wavelength of about 800 nm
or greater, but the light absorption of these compounds in the
wavelength region of about 380 nm to 780 nm (visible light
region), which can be perceived by humans, is weak in
comparison with the former (light having a wavelength of about
800 nm or greater).
[0030]
The inventors, based on the wide bandgap of tungsten
trioxide, used the backbone structure of tungsten trioxide,
reduced the oxygen content of the tungsten trioxide or added
positive ions to generate conduction electrons (free
electrons), controlled the particle diameter and shape of the
tungsten oxide particles and the composite tungsten oxide
particles, manufactured particles that had electrical
conductivity while allowing light in the visible region to
pass, and used the manufactured particles to obtain a visible
light transmitting particle-dispersed electrical conductor.
DISCLOSURE OF THE INVENTION
[0031]
Specifically, in order to solve the aforementioned
problems, a first aspect of the present invention provides a
visible light transmitting particle-dispersed electrical
conductor, which is a plural aggregate of electroconductive
particles composed of a tungsten oxide expressed by the
general formula WyOz (where W is tungsten, O is oxygen, and
2.2 s; z/y s 2.999), and/or a composite tungsten oxide
expressed by the general formula MxWyOz (where M is one or
more elements selected from H, He, alkali metals, alkalineearth
metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co,
Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge,
Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb. V, Mo, Ta, Re, Be,
Hf, Os, Bi, and I; W is tungsten; O is oxygen; 0.001 s x/y s 1,
and 2.2 ^ z/y ss 3.0), wherein the particle diameter is 1 nm or
greater, the particles have visible light transmitting
characteristics, and the pressed powder resistance of the
particles measured under a pressure of 9.8 MPa is 1.0 Q-cm or
less.
[0032]
A second aspect provides the visible light transmitting
particle-dispersed electrical conductor of the first aspect,
wherein the electroconductive particles contain acicular
crystals or are entirely composed of acicular crystals, the
ratio of the major and minor axes (major axis/minor axis) in
the acicular crystals is 5 or greater, and the length of the
major axis ranges from 5 run or greater to 10,000 \wi or less.
[0033]
A third aspect provides the visible light transmitting
particle-dispersed electrical conductor of the first aspect,
wherein the electroconductive particles contain tabular
crystals or are entirely composed of tabular crystals, the
thickness of the tabular crystals ranges from 1 nm or greater
to 100 \m or less, the maximum diagonal length of the tabular
surfaces in the tabular crystals ranges from 5 nm or greater
to 500 yni or less, and the ratio of the maximum diagonal
length and the thickness of the tabular crystals (maximum
diagonal length/thickness) is 5 or greater.
[0034]
A fourth aspect provides the visible light transmitting
particle-dispersed electrical conductor of any of the first to
third aspects, wherein the electroconductive particles of the
tungsten oxide include a Magneli phase having a composition
ratio expressed by the general formula WyOz (where W is
tungsten, O is oxygen, and 2.45 s z/y ^ 2.999).
10035]
A fifth aspect provides the visible light transmitting
particle-dispersed electrical conductor of any of the first to
fourth aspects, wherein the crystal structure of the
electroconductive particles of the composite tungsten oxide
expressed by the formula MxWyOz has an amorphous structure, or
a cubic, tetragonal, or hexagonal tungsten bronze structure.
[0036]
A sixth aspect provides the visible light transmitting
particle-dispersed electrical conductor of the fifth aspect,
wherein the added element M in the electroconductive particles
of the composite tungsten oxide expressed by the formula
MxWyOz is one or more elements selected from Cs, Rb, K, Tl, Ba,
In, Li, Ca, Sr, Fe, and Sn.
[0037]
A seventh aspect provides the visible light transmitting
particle-dispersed electrical conductor of any of the first to
sixth aspects, wherein the shape of the electroconductive
particles is one or more shapes selected from granular,
acicular, or tabular.
[0038]
An eighth aspect provides the visible light transmitting
particle-dispersed electrical conductor of any of the first to
seventh aspects, wherein the visible light transmitting
particle-dispersed electrical conductor is film-shaped.
[0039]
A ninth aspect provides the visible light transmitting
particle-dispersed electrical conductor of any of the first to
eighth aspects, wherein the visible light transmitting
particle-dispersed electrical conductor contains a binder.
[0040]
A tenth aspect provides the visible light transmitting
particle-dispersed electrical conductor of the ninth aspect,
wherein the binder is a transparent resin or a transparent
dielectric.
[0041]
An eleventh aspect provides electroconductive particles
that are used in the visible light transmitting particledispersed
electrical conductor of any of the first to tenth
aspects.
[0042]
A twelfth aspect provides a visible-light-transmitting
electroconductive article, wherein the visible light
transmitting particle-dispersed electrical conductor of any of
the first to tenth aspects is formed on a base material.
[0043]
A thirteenth aspect provides a method for manufacturing
electroconductive particles that contain a composite tungsten
oxide expressed by the general formula WyOz (where W is
tungsten, 0 is oxygen, and 2.2 ^ z/y s 2.999), and/or a
composite tungsten oxide expressed by the general formula
MxWyOz (where M is one or more elements selected from H, He,
alkali metals, alkaline-earth metals, rare earth elements, Mg,
Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd,
Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti,
Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; W is tungsten; O is
oxygen; 0.001 ^ x/y a 1.1; and 2.2 ss z/y s 3.0), wherein
the tungsten compound as a starting material of the
electroconductive particles is heat treated in a reducing gas
and/or an inert gas atmosphere to manufacture the
electroconductive particles.
[0044]
A fourteenth aspect provides the method for manufacturing
electroconductive particles of the thirteenth aspect, wherein
the heat treatment includes heat treating a tungsten compound,
which is a starting material of the electroconductive
particles, at 100°C or greater and 850°C or less in an
atmosphere of a reducing gas, and subsequently heat treating
the tungsten compound as required at a temperature of 550°C or
greater and 1,200°C or less in an atmosphere of an inert gas.
[0045]
A fifteenth aspect provides the method for manufacturing
electroconductive particles of the thirteenth or fourteenth
aspects, wherein a tungsten compound as a starting material of
the electroconductive particles is one or more materials
selected from tungsten trioxide; tungsten dioxide; a hydrate
of tungsten oxide; tungsten hexachloride; ammonium tungstate;
tungstic acid; a hydrate of tungsten oxide obtained by
dissolving tungsten hexachloride in an alcohol and then drying
the solution; a hydrate of tungsten oxide obtained by
dissolving tungsten hexachloride in an alcohol, adding water
to the solution to form a precipitate, and drying the
precipitate; a tungsten compound obtained by drying an aqueous
solution of ammonium tungstate; and a metal tungsten powder.
[0046]
A sixteenth aspect provides the method for manufacturing
electroconductive particles of the thirteenth to fifteenth
aspects, wherein one or more powders selected from a powder in
which a tungsten compound, which is a starting material of the
electroconductive particles of the fifteenth aspect, and an
element or compound containing an element M (where M is one or
more elements selected from H, He, alkali metals, alkalineearth
metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co,
Rh, Ir, Ni, Pd, Pt. Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge,
Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be,
Hf, Os, Bl, and I) are mixed; and a powder, obtained by mixing
a solution or liquid dispersion of the tungsten compound and a
solution or liquid dispersion of the compound containing the
element M and drying the solution, is used as the tungsten
compound that is the starting material of the
electroconductive particles.
[0047]
Tungsten trioxide is a wide band gap material that
transmits visible light, but the material is not
electroconductive. The inventors used the backbone structure
of tungsten trioxide, reduced the oxygen content of the
tungsten trioxide or added positive ions to generate
conduction electrons (free electrons), and manufactured a
transparent electroconductive film that retains electrical
conductivity while still allowing visible light to pass.
[0048]
Also, Mo, Nb, Ta, Mn, V, Re, Ft, Pd, and Ti are elements
that have the same properties as the above-de scribed tungsten
(these elements may hereinafter be abbreviated as "element A").
Similar to tungsten oxide, oxides of element A have the same
structure as so-called tungsten bronze, which contains
electropositive elements in the crystal. In view of this fact,
the inventors arrived at the idea of combining element A and
tungsten oxide, or employing an electroconductive film based
on a so-called tungsten bronze structure in which an element A
is used, and manufactured electroconductive films.
[0049]
In order to solve the aforementioned problems, a
seventeenth aspect provides a transparent electroconductive
film composed of a tungsten oxide expressed by the general
formula WyOz (where W is tungsten, O is oxygen, and 2.2 * z/y
2.999), and/or a composite tungsten oxide expressed by the
general formula MxWyOz (where M is one or more elements
selected from H, He, alkali metals, alkaline-earth metals,
rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni,
Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb,
B, F. P, S, Se. Br, Te, Ti, Nb, V, Mo, Ta. Re, Be, Hf, Os, Bi,
and I; W is tungsten; O is oxygen; 0.001 £ x/y s 1.1; and 2.2
£ z/y £ 3.0), wherein the maximum transmittance in the region
of 400 nm or greater to 780 nm or less ranges from 10% or
greater to less than 92%, and the surface resistance of the
film is 1.0 x 1010 £2/square or less.
[0050]
An eighteenth aspect provides the transparent
electroconductive film of the seventeenth aspect, wherein the
element M Includes one or more elements selected from Cs, Rb,
K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn; and the composite oxide
expressed by the general formula MxWyOz has a hexagonal
crystal structure.
[0051]
A nineteenth aspect provides the transparent
electroconductive film of the seventeenth or eighteenth
aspects, wherein the tungsten oxide has a Magneli phase having
a composition ratio expressed by the general formula WyOz
(where W is tungsten, O is oxygen, and 2.45 s z/y s 2.999).
[0052]
A twentieth aspect provides the transparent
electroconductive of the seventeenth to nineteenth aspects,
wherein the composite tungsten oxide expressed by the general
formula MxWyOz has an amorphous structure, or one or more
structures selected from cubic, tetragonal, and hexagonal
tungsten bronze structures.
[0053]
A twenty-first aspect provides the transparent
electroconductive of the twentieth aspect, wherein the added
element M in the hexagonal composite tungsten oxide expressed
by the formula MxWyOz is one or more elements selected from Cs,
Rb, K, Tl, Ba, In, Li. Ca, Sr, Fe, and Sn.
[0054]
A twenty-second aspect provides a transparent
electroconductive film composed of a composite oxide expressed
by the general formula MEAGW(i-G)Oj (where M is one or more
elements selected from H, He, alkali metals, alkaline-earth
metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh,
Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn. Cd, Al, Ga, In, Tl, Si, Ge, Sn,
Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf,
Os, Bi. and I; A is one or more elements selected from Mo, Nb,
Ta, Mn, V, Re, Pt, Pd, and Ti; W is tungsten; O is oxygen; 0 E £ l . 2 ; 0 transmittance in the region of 400 nm or greater to 780 nra or
25
less ranges from 10% or greater to less than 92%, and the
surface resistance of the film is 1.0 x 1010 £2/square or less.
[0055]
A twenty-third aspect provides the transparent
electroconductive film of the twenty-second aspect, wherein
the composite oxide expressed by the general formula MgAGWd-GjOj
has an amorphous structure, or one or more structures selected
from cubic, tetragonal, and hexagonal tungsten bronze
structures.
[0056]
A twenty-fourth aspect provides the transparent
electroconductive film of the twenty-second or twenty-third
aspect, wherein the element M includes one or more elements
selected from Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn;
and the composite oxide expressed by the general formula
MEAGW(i-G)Oj has a hexagonal crystal structure.
[0057]
A twenty-fifth aspect provides a transparent
electroconductive article, wherein the transparent
electroconductive film of any of the seventeenth to twentyfourth
aspects is formed on a base material.
[0058]
A twenty-sixth aspect provides the transparent
electroconductive article of the twenty-fifth aspect, wherein
the thickness of the transparent electroconductive film ranges
from 1 nm or greater to 5,000 run or less.
26
[0059]
A twenty-seventh aspect provides an infrared-shielding
article, wherein the transparent electroconductive film of any
of the seventeenth to twenty-sixth aspects is formed on a base
material and has an infrared-shielding function.
[0060]
A twenty-eighth aspect provides a method for
manufacturing a transparent electroconductive film composed of
a tungsten oxide expressed by the general formula WyOz (where
W is tungsten, O is oxygen, and 2.2 s z/y s; 2.999), and/or a
composite tungsten oxide expressed by the general formula
MxWyOz (where M is one or more elements selected from H, He,
alkali metals, alkaline-earth metals, rare earth elements, Mg,
Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd,
Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti,
Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; W is tungsten; O is
oxygen; 0.001 * x/y £ 1.1; and 2.2 £ z/y £ 3.0), and/or a
composite oxide expressed by the general formula MEAGW(i-G)Oj
(where the element A is one or more elements selected from Mo,
Nb. Ta. Mn. V, Re, Pt, Pd, and Ti; 0 2 £ J' ss 3), wherein
a solution composed of the tungsten oxide, and/or the
composite tungsten oxide, and/or the starting material
compound of the composite oxide is applied to a base material
and heat treated in an atmosphere of a reducing gas and/or an
inert gas to manufacture the transparent electroconductive
film.
[0061]
A twenty-ninth aspect provides the method for
manufacturing a transparent electroconductive film of the
twenty-eighth aspect, wherein a surfactant is added to the
solution composed of the tungsten oxide, and/or the composite
tungsten oxide, and/or the starting material compound of the
composite oxide; and the solution is then applied to a base
material.
[0062]
A thirtieth aspect provides the method for manufacturing
a transparent electroconductive film of the twenty-eighth or
twenty-nine aspects, wherein the solution composed of the
tungsten oxide, and/or the composite tungsten oxide, and/or
the starting material compound of the composite oxide is a
solution obtained by dissolving tungsten hexachloride in an
alcohol when tungsten is added, and/or is an aqueous solution
of ammonium tungstate.
[0063]
A thirty-first aspect provides the method for
manufacturing a transparent electroconductive film of the
twenty-eighth to thirtieth aspects, wherein a solution,
obtained by dissolving and mixing an aqueous solution of
ammonium tungstate and/or a solution obtained by dissolving
tungsten hexachloride in alcohol according to the thirtieth
aspect, and a compound having the element M (where M is one or
more elements selected from H, He, alkali metals, alkalineearth
metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co,
Rh. Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl. Si, Ge.
Sn, Pb, Sb, B, F. P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be,
Hf, Os, Bi, and I), is applied to a base material directly or
after a surfactant has been added.
[0064]
A thirty-second aspect provides the method for
manufacturing a transparent electroconductive film of any of
the twenty-eighth to thirty-first aspects, wherein the heat
treatment is performed at a temperature ranging from 100°C or
greater to 800°C or less in an atmosphere of a reducing gas,
and is subsequently performed as required at a temperature
ranging from 550°C or greater to 1,200°C or less in an
atmosphere of an inert gas.
[0065] A material containing free electrons is commonly known to
reflect/absorb electromagnetic waves in the vicinity of the
region of solar light having a wavelength of 200 nm 2,600 nm
produced by plasma vibrations. It is known that when a powder
of such a material is formed into nanoparticles that are
smaller than the wavelength of light, geometrical scattering
in the visible light region (wavelengths from 380 nm to 780 nm)
is reduced and transparency in the visible light region can be
obtained. In the present specification, "transparency" is
used in the sense that scattering of visible light is low and
transmission characteristics are high.
[0066]
On the other hand, so-called tungsten bronze, which is
obtained by adding Na or another electropositive element to
tungsten trioxide, is an electroconductive material and is
known to be a material that has free electrons. Also, Mo, Nb,
Ta, Mn, V, Re, Pt, Pd, and Ti (hereinafter referred to as
"element A") are known, in addition to tungsten, as elements
having the same properties as those described above. Similar
to tungsten oxide, oxides of element A are known to have a socalled
tungsten bronze structure that contains electropositive
elements in the crystal. An analysis of a single crystal or
the like of these materials suggests that electroconductive
characteristics are present and that free electrons respond to
visible light.
The inventors arrived at the present invention upon
discovering that it is possible to manufacture an effective
visible-light-transmitting near-infrared-shielding body and a
visible-light-transmitting electroconductive infraredshielding
body by increasing the amount of free electrons
contained in composite oxide nanoparticles that contain
tungsten or an element A.
[0067]
The Inventors have also discovered that a film obtained
by dispersing composite oxide nanoparticles in a suitable
medium can more effectively absorb solar light, particularly
in a near-infrared region, and can at the same time transmit
visible light without the use light interference, and that
these properties are superior to those of a film fabricated by
spraying or a film fabricated by sputtering, vapor deposition,
or ion-plating, as well as chemical vapor deposition (CVD) or
another dry vacuum deposition method. These findings
ultimately led to the present invention. The inventors also
discovered that this dispersion itself exhibits electrical
conductivity when these nanoparticles make contact with each
other in the dispersion, because the composite oxide
nanoparticles are electroconductive.
[0068]
In order to solve the aforementioned problems, a thirtythird
aspect provides an infrared-shielding nanoparticle
dispersion obtained by dispersing infrared-shielding
nanoparticles in a medium, wherein the Infrared-shielding
nanoparticles include composite tungsten oxide nanoparticles
expressed by the general formula MEAGW(i-G)Oj (where M is one or
more elements selected from H, He, alkali metals, alkalineearth
metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co,
Rh, Ir, Ni, Pd. Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge,
Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be,
Hf, Os, Bi, and I; A is one or more elements selected from Mo,
Nb, Ta, Mn, V, Re, Pt, Pd, and Ti; W is tungsten; O is oxygen;
0 [0069]
A thirty-fourth aspect provides the infrared-shielding
nanoparticle dispersion of the thirty-third aspect, wherein
the composite oxide nanoparticles expressed by the general
formula Msf^(i-G}Oj include one or more nanoparticles selected
from composite oxide nanoparticles having a hexagonal crystal
structure, composite oxide nanoparticles having a tetragonal
crystal structure, and composite oxide nanoparticles having a
cubic crystal structure.
[0070]
A thirty-fifth aspect provides the infrared-shielding
nanoparticle dispersion of the thirty-third or thirty-fourth
aspects, wherein the element M includes one or more elements
selected from Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn;
and the composite oxide expressed by the general formula
MEAGW(i-G)Oj has a hexagonal structure.
[0071]
A thirty-sixth aspect provides the infrared-shielding
nanoparticle dispersion of any of the thirty-third to thirtyfifth
aspects, wherein the surfaces of the infrared-shielding
nanoparticle dispersion are covered by an oxide composed of
one or more elements selected from Si, Ti, Zr, and Al.
[0072]
A thirty-seventh aspect provides the infrared-shielding
nanoparticle dispersion of any of the thirty-third to thirtysixth
aspects, wherein the medium is resin or glass.
[0073]
A thirty-eighth aspect provides the infrared-shielding
nanoparticle dispersion of the thirty-seventh aspect, wherein
the resin is one or more resins selected from polyethylene
resin, polyvinyl chloride resin, polyvinylidene chloride resin,
polyvinyl alcohol resin, polystyrene resin, polypropylene
resin, ethylene-vinyl acetate copolymer, polyester resin,
polyethylene terephthalate resin, fluorine resin,
polycarbonate resin, acrylic resin, and polyvinyl butyral
resin.
[0074]
A thirty-ninth aspect provides an infrared-shielding body,
wherein the infrared-shielding nanoparticle dispersion of any
of the thirty-third to thirty-eighth aspects is formed in a
plate shape, film shape, or thin film shape.
[0076]
A fortieth aspect provides the infrared-shielding body of
the thirty-ninth aspect, wherein V is 10% or greater, where V
is the maximum transmlttance of all light rays in the
wavelength region of 400 nm to 700 nm; and the minimum
transmittance of all light rays in the wavelength region of
700 nm to 2,600 nm is equal to or less than the value V, and
is 65% or less.
[0077]
A forty-first aspect provides the infrared-shielding body
of the thirty-ninth aspect, wherein V is 10% or greater, where
33
V is the maximum transmittance of all light rays in the
wavelength region of 400 nm to 700 nm; and the surface
resistance of the film is 1.0 x 1010 Q/sguare or less.
[0078]
A forty-second aspect provides a method for manufacturing
infrared-shielding nanoparticles composed of composite oxide
nanoparticles expressed by the general formula MEAGW(i-G)Oj
(where M is one or more elements selected from H, He, alkali
metals, alkaline-earth metals, rare earth elements, Mg, Zr, Cr,
Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga,
In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V,
Mo, Ta, Re, Be, Hf, Os, Bi, and I; A is one or more elements
selected from Mo, Nb, Ta, Mn, V, Re, Pt, Pd, and Ti; W is
tungsten; O is oxygen; 0 wherein
the starting material of the composite oxide
nanoparticles is heat treated in an atmosphere of a reducing
gas and/or an inert gas at 250°C or greater to manufacture the
composite oxide nanoparticles.
[0078]
A forty-third aspect provides the method for
manufacturing infrared-shielding nanoparticles of the fortysecond
aspect, wherein the starting material of the composite
oxide nanoparticles is a tungsten compound, an element A
compound, and an element M compound, and is one or more
compounds selected from oxides, hydrated oxides, chlorides,
ammonium salts, carbonates, nitrates, sulfates, oxalates,
hydroxides, peroxides, and simple metals of the corresponding
element.
[0079]
A forty-fourth aspect provides the method for
manufacturing infrared-shielding nanoparticles of the fortysecond
aspect, wherein the starting material of the composite
oxide nanoparticles is a powder obtained by mixing a solution
composed of a tungsten compound, an element A compound, and an
element M compound, and then drying the solution.
[0080]
A forty-fifth aspect provides infrared-shielding
nanoparticles manufactured using the method for manufacturing
infrared-shielding nanoparticles of any of the forty-second to
forty-fourth aspects, wherein the nanoparticles include
composite oxide nanoparticles expressed by the general formula
MEAGW(i-G)Oj (where M is one or more elements selected from H, He,
alkali metals, alkaline-earth metals, rare earth elements, Mg,
Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd,
Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti,
Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; A is one or more
elements selected from Mo, Nb, Ta, Mn, V, Re, Pt, Pd, and Ti;
W is tungsten; O is oxygen; 0 3).
[Effects of the Invention]
[0081]
The visible light transmitting particle-dispersed
electrical conductor of the first to tenth aspects has
excellent transmittance of light in the visible region and
excellent electrical conductivity because the electrical
conductor has electroconductive particles in which the oxygen
content of tungsten trioxide is reduced to cause conduction
electrons to be generated, and/or electroconductive particles
that include a composite tungsten oxide that is made to
generate conduction electrons by adding positive ions to
tungsten trioxide.
The electroconductive particles of the eleventh aspect
have excellent electrical conductivity and excellent
transmittance of visible light, and can therefore be
advantageously applied to the visible light transmitting
particle-dispersed electrical conductor of the first to tenth
aspects.
The visible-light-transmitting particle-dispersed
electroconductive article of the twelfth aspect has excellent
electrical conductivity and excellent transmittance of visible
light.
In accordance with the method for manufacturing
electroconductive particles of the thirteenth to sixteenth
aspects, the electroconductive particles can be manufactured
at low cost by using a simple method because the particles can
be obtained by heat treating a tungsten compound, which is a
starting material of the electroconductive particles, in an
atmosphere of a reducing gas and/or inert gas.
[0082]
In accordance with the seventeenth to twenty-seventh
aspects, the backbone structure of a tungsten trioxide that
transmits light in the visible range but does not have
electrical conductivity, or a composite oxide of tungsten and
an element A is used, and since conduction electrons are
generated in the tungsten trioxide or composite oxide of
tungsten and an element A, an inexpensive transparent
electroconductive film that has excellent electrical
conductivity and transmlttance to visible light can be
obtained. The film has a tungsten oxide in which the oxygen
content is reduced or a composite tungsten oxide in which
conduction electrons are generated by adding positive ions.
Also, a transparent electroconductive article that uses the
transparent electroconductive film can be provided with
electrical conductivity via the conduction electrons, and can
transmit light in the visible range at the same time.
[0083]
In accordance with the twenty-eighth to thirty-second
aspect, the transparent electroconductive film can be obtained
by a simple method in which a starting tungsten material
solution is applied to a base material and then heat treated
in an atmosphere of a reducing gas and/or inert gas.
Therefore, the method is useful because the film can be easily
manufactured using inexpensive materials in comparison with a
conventional indium compound.
[0084]
The infrared-shielding nanoparticle dispersion of the
thirty-third to forty-first aspects is an infrared-shielding
nanoparticle dispersion obtained by dispersing infraredshielding
nanoparticles in a medium, wherein the infraredshielding
nanoparticles include composite oxide nanoparticles
expressed by the general formula MEAGW(i-G)Oj (where M is one or
more elements selected from H, He, alkali metals, alkalineearth
metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co,
Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn. Cd, Al, Ga, In, Tl, Si, Ge,
Sn, Pb. Sb, B, F, P, S, Se, Br, Te, Ti, Nb. V, Mo, Ta, Re, Be,
Hf, Os, Bi, and I; A is one or more elements selected from Mo,
Nb, Ta, Mn, V, Re, Pt, Pd, and Ti; W is tungsten; O is oxygen;
0 electrons in these composite oxides is increased, and this
film can more effectively absorb and shield solar light,
particularly in a near-infrared region, and can simultaneously
retain transmlttance in the visible light region in comparison
with a film fabricated by spraying, or a film fabricated by
sputtering, vapor deposition, or ion-plating, as well as
chemical vapor deposition (CVD) or another dry method vacuum
deposition method.
[0085]
Since these infrared-shielding nanoparticles have
electrical conductivity, the dispersion itself can function as
an electroconductive material by causing the particles to make
contact with each other in the infrared-shielding nanoparticle
dispersion. The dispersion can also be used as an infraredshielding
body that transmits visible-light and has electrical
conductivity.
[0086]
The infrared-shielding nanoparticle dispersion has
industrial utility in that the body can be manufactured at low
cost without the use of a vacuum apparatus or other bulky
equipment.
BEST MODE FOR CARRYING OUT THE INVENTION
[0087]
Embodiments of the present invention are described below
in the following order: [1] visible light transmitting
particle-dispersed electrical conductor, electroconductive
particles, visible-light-transmitting electroconductive
article, and method for manufacturing the same; [2]
transparent electroconductive film and method for
manufacturing the same, transparent electroconductive article,
and Infrared-shielding article; and [3] infrared-shielding
nanoparticle dispersion. Infrared-shielding body, method for
manufacturing infrared-shielding nanoparticles, and infraredshielding
nanoparticles.
[0088]
[1] Visible light transmitting particle-dispersed
electrical conductor, electroconductive particles, visiblelight-
transmitting electroconductive article, and method for
manufacturing the same
[0089]
The visible light transmitting particle-dispersed
electrical conductor of the present Invention has a tungsten
oxide expressed by the general formula WyOz (where W is
tungsten, O is oxygen, and 2.2 s z/y £ 2.999), and/or a
composite tungsten oxide expressed by the general formula
MxWyOz (where M is one or more elements selected from H, He,
alkali metals, alkaline-earth metals, rare earth elements, Mg,
Zr, Cr, Mn, Fe, Ru, Co, Rh. Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd,
Al, Ga, In, Tl, Si, Ge, Sn. Pb, Sb, B, F, P, S, Se, Br, Te, Ti,
Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; W is tungsten; O is
oxygen; 0.001 s: x/y s 1.1; and 2.2 £ z/y s 3.0), wherein the
particle diameter is 1 run or greater, the particles have
visible light transmitting characteristics, and the pressed
powder resistance of the particles measured under a pressure
of 9.8 MPa is 1.0 Q-cm or less. The resulting
electroconductive particles are aggregated to bring the
particles into contact with each other and to form an
electroconductive body.
[0090]
When the electroconductive particles Include acicular
crystals or are entirely composed of acicular crystals, the
ratio of the major and minor axes (major axis/minor axis) in
the acicular crystals is 5 or greater, and the length of the
major axis ranges from 5 nm or greater to 10,000 [im. When the
electroconductive particles include tabular crystals or are
entirely composed of tabular crystals, the thickness of the
tabular crystals ranges from 1 nm or greater to 100 nm or less,
the maximum diagonal length of the tabular surfaces in the
tabular crystals ranges from 5 nm or greater to 500 \m or less,
and the ratio of the maximum diagonal length and the thickness
of the tabular crystals (maximum diagonal length/thickness) is
5 or greater.
The visible light transmitting particle-dispersed
electrical conductor and the electroconductive particles used
in the electrical conductor are described in detail below.
[0091]
1. Electroconductive particles
Tungsten trioxlde (WO3) generally has excellent visiblelight
transmittance, but since effective conduction electrons
are not present, tungsten trioxlde is not an effective
electroconductive material. It is known that free electrons
can be generated in W03 by reducing the ratio of oxygen to
tungsten in the WO3 to less than 3. The inventors discovered
that, in specific areas of the tungsten/oxygen composition
range, there is a uniquely effective range in which the
composition acts as an electroconductive material.
[0092]
In the tungsten oxide described above, the
tungsten/oxygen composition range is one in which the
composition ratio of oxygen to tungsten is less than 3, and
the range 2.2 £ z/y s: 2.999 Is preferred when the
electroconductive particles have the formula WyOz. When the
value of z/y is 2.2 or greater, formation of an unwanted WO2
crystal phase in the electroconductive material can be avoided
and the material can be provided with chemical stability, and
can therefore be used as an effective electroconductive
material. When the value of z/y is 2.999 or less, the
required amount of free electrons can be generated to produce
an electroconductive material.
[0093]
In the above-described composite tungsten oxide,
conduction electrons (free electrons) are generated in the W03
and an effective electroconductive material is obtained by
adding an element M (where M is one or more elements selected
from H, He, alkali metals, alkaline-earth metals, rare earth
elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu,
Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S,
Se, Br, Te, Ti, Nb. V, Mo, Ta, Re, Be, Hf, Os, Bi, and I) to
tungsten trloxlde (WO3).
[0094]
In other words, the electroconductive material must be a
composite tungsten oxide expressed by the general formula
MxWyOz (where M is one or more elements selected from H, He,
alkali metals, alkaline-earth metals, rare earth elements, Mg,
Zr, Cr, Mn. Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd,
Al, Ga, In, Tl. Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti,
Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; W is tungsten; O is
oxygen; 0.001 s x/y £ 1.1; and 2.2 s z/y £ 3.0). From the
standpoint of stability, the element M is preferably one or
more elements selected from alkali metals, alkaline-earth
metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh,
Ir, Ni, Pd. Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si. Ge, Sn,
Pb, Sb, B. F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf,
Os, Bi, and I.
[0095]
In relation to the oxygen content and the added amount of
the element M, the material is preferably one in which the
ranges 0.001 * x/y * 1.1, and 2.2s; z/y £ 3.0 are satisfied
when the electroconductive particles have the formula MxWyOz
(where M is as described above, W is tungsten, and O is
oxygen). As the addition amount of the element M is Increased,
the supply amount of conduction electrons tends to Increase as
well. This is due to the fact that, as noted above, MxWyOz
has the crystal structure of so-called tungsten bronze. In
stoichiometric terms, the addition amount of the element M per
mole of tungsten, for example, is preferably no more than
about 0.33 mol in the case of a hexagonal tungsten bronze
crystal structure, preferably no more than about 0.5 mol in
the case of a tetragonal tungsten bronze crystal structure,
and preferably no more than about 1 mol in the case of a cubic
tungsten bronze crystal structure. However, since the abovedescribed
crystal structures can occur in various modes, the
addition amount of the element M is not necessarily limited to
the addition amounts described above.
[0096]
Next, the value of z/y, which is used to control the
oxygen content, in the composite tungsten oxide expressed by
MxWyOz, is described below. In addition to the fact that
conduction electrons (free electrons) are produced in the same
range (2.2 2; z/y a 2.999) as the tungsten oxide WyOz described
above, the value of z/y preferably satisfies the range 2.2 s
z/y £ 3.0, and more preferably satisfies the range 2.72 s z/y
£ 3.0, because conduction electrons are supplied by the
addition of the above-described element M even when z/y = 3.0.
[0097]
Also, the electroconductive particles of the present
embodiment preferably have a particle size of 1 nm or greater.
The electroconductive particles absorb a considerable amount
of light in the vicinity of the wavelength 1,000 nm, and the
transmission color tone is often between a blue' color and a
green color. The size of the particles can be selected based
on the intended use. First, when the particles are to be used
in applications in which transparency is to be retained, the
particle diameter is preferably 800 nra or less. This is due
to the fact that particles having a diameter of less than 800
nm do not perfectly shield light by scattering the light,
visibility is retained in the visible light region, and
transparency can be retained at the same time with good
efficiency. In the particular case that importance in placed
on transparency in the visible light region, the scattering
produced by the particles is preferably given further
consideration.
[0098]
When importance is placed on reducing scattering produced
by the particles, the particle diameter is 200 nm or less, and
more preferably 100 nm or less. The reason for this is that
if the particle diameter is too small, the scattering of light
in the visible light wavelength region of 380 nm to 780 nm is
reduced due to geometrical scattering or Mie scattering.
Therefore, it is possible to avoid a situation in which the
film becomes similar to clouded glass and clear transparency
cannot be obtained. In other words, when the particle
diameter is 200 nm or less, the geometrical scattering or Mie
scattering is reduced and a Rayleigh scattering region is
formed. This is due to the fact that the scattered light is
reduced in an inverse proportion to the particle diameter by a
factor of 6 in this Rayleigh scattering region, and the
scattering is reduced as the particles are made smaller and
the transparency is enhanced. When the particle diameter is
100 nm or less, the amount of scattered light is very low, and
such a situation is not preferred. From the standpoint of
avoiding the scattering of light, the particle diameter is
preferably small. Also, if the particle diameter is 1 nm or
greater, the particles are easy to handle and manufacture on a
commercial scale.
[0099]
To improve the electrical conductivity of the
electroconductive particles, the shape of the
electroconductive particles used in the present invention is
preferably acicular or tabular. This is because the
electrical conductivity of the electroconductive body is
reduced due to the contact resistance between the particles,
the number of contact points between the particles can
therefore be reduced as long as the particle dispersion is
composed of acicular or tabular electroconductive particles,
and an electroconductive body that has higher electrical
conductivity can be obtained.
Therefore, when the electroconductive particles used in
the present invention include tabular crystals or are entirely
composed of tabular crystals, the thickness of the tabular
crystal particles ranges from 1 nm or greater to 100 JA or less,
the maximum diagonal length of the tabular surfaces in the
tabular crystals ranges from 5 ran or greater to 500 yon or less,
and the ratio of the maximum diagonal length and the thickness
of the tabular crystals in the tabular plane is 5 or greater.
[0100]
When measured under a pressure of 9.8 MPa, the pressed
powder resistance of the electroconductive particles used in
the present invention and obtained in this manner is 1.0 Q-cm
or less. If the pressed powder resistance is 1.0 Q-cm or less,
an effective electrical conductor film can be obtained and the
range of application can be expanded, resulting in an
advantageous situation.
[0101]
The tungsten oxide particles constituting the
electroconductive particles of the present embodiment
preferably has a Magneli phase having a composition ratio
expressed by the general formula WyOz (where W is tungsten, O
is oxygen, 2.45 £ z/y a 2.999). A Magneli phase is chemically
stable and is advantageous as an electroconductive material.
[0102]
Here, the electrical conduction mechanism of the
transparent electroconductive film of the present invention is
briefly described with reference to the drawings. FIGS. 1A to
ID are schematic drawings showing the crystal structure of
tungsten oxide and a composite tungsten oxide, wherein FIG. 1A
is the crystal structure of Wi8O49 ((010) projection); FIG. IB
is the crystal structure of cubic tungsten bronze ((010)
projection); FIG. 1C is the crystal structure of tetragonal
tungsten bronze ((001) projection); and FIG. ID is the crystal
structure of hexagonal tungsten bronze ((001) projection).
The structure of tungsten trioxide has an octahedral
structure composed of WOs, and may be regarded as a single unit.
W atoms are positioned in the octahedral structure, and oxygen
is positioned at the apexes of the octahedral structure. In
all octahedral structures, the apexes are shared with an
adjacent octahedral structure. In this case, conduction
electrons are not present in the structure. On the other hand,
the Magneli phase expressed by WO2.9 or another composition
ratio is a structure in which the octahedral structure of WO6
shares edges and apexes in an orderly fashion. Wi8O49 (WO2.?2)
having the structure shown in FIG. 1(A) has an orderly
structure in which the octahedral structure of WO6 and the
decahedral structure of WOio as a single unit share edges and
apexes. Tungsten oxide having such a structure is believed to
be provided with electrical conductivity via the contribution
of electrons released by oxygen as conduction electrons.
The above-described structure of tungsten trioxide
produces conduction electrons in a completely uniform,
nonuniform, or amorphous structure, and electroconductive
characteristics can be obtained.
[0103]
The composite tungsten oxide expressed by the formula
MxWyOz preferably has an amorphous structure or a cubic,
tetragonal, or hexagonal tungsten bronze structure.
[0104]
With this composite tungsten oxide, the element M is
positioned in gaps resulting from the sharing of apexes by an
octahedral structure, as shown in FIGS. IB to ID. It is
believed that conduction electrons are generated by adding
such elements M. The structure of a composite tungsten oxide
is typically cubic, tetragonal, or hexagonal, and a structural
example of each is shown in FIGS. IB, 1C, and ID. These
composite tungsten oxides have a structure-based upper limit
to the amount of addition element, and the maximum addition
amount of the element M per mole of W is as follows: 1 mol in
the case of a cubic system, about 0.5 mol in the case of a
tetragonal system (this varies depending on the addition
amount, but 0.5 mol can be easily produced on a commercial
scale), and 0.33 mol in the case of a hexagonal system.
However, these structures are difficult to define in a simple
manner, and the range of maximum addition amounts of the
addition element M described above is an example that
particularly shows a basic preferred range. This invention is
not limited to this range. Several types of structures may be
adopted in the crystal structure by compositing materials.
The above-described structure is a representative structure,
and no limitation is imposed by the structure.
[0105]
In a composite tungsten oxide, the optical
characteristics vary depending on the above-described
structure. Hexagonal systems in particular tend to have a
light absorption region based on conduction electrons in the
near-infrared region having longer wavelengths, and absorption
in the visible light region is also low. Next, tetragonal
systems and cubic systems tend to absorb light having shorter
wavelengths by means of conduction electrons, and absorption
in the visible light region is also high. Accordingly, a
composite tungsten oxide, which has a hexagonal structure, is
preferred for the above-stated reasons as the transparent
electroconductive film capable of transmitting more visible
light.
[0106]
It is commonly known that a hexagonal system is formed
when an element M having a large ion radius is added to a
composite tungsten oxide. Specifically, when any of the
elements Cs, K, Rb, Tl, Ba, In, Li, Ca, Sr, Fe, and Sn are
added, a hexagonal system is readily formed, and such a
situation is preferred. However, as long as the added element
M is present in the gaps of the hexagonal structure, as shown
in FIG. ID, for example, a WO6 unit can be formed using an
element other than those noted above, and no limitation is
imposed by these elements. Also, a composite tungsten oxide
having these hexagonal structures may be a uniform crystal
structure or an irregular crystal structure.
In this case, it is possible to use both methods, i.e.,
to limit the above-described oxygen content and to add an
element M for generating conduction electrons to the tungsten
trioxide (WO3). Also, when the transparent electroconductive
film described above is used as an infrared-shielding film, a
material that is suitable for the desired purpose, e.g., an
element M, may be selected at an appropriate time.
[0107]
When electroconductive particles of a composite tungsten
oxide having a hexagonal structure are formed in a uniform
structure, the addition amount of the element M is preferably
0.1 or more and 0.4 or less, and is more preferably 0.33.
This is because the value theoretically calculated from the
crystal structure is 0.33, and desirable electroconductive
characteristics can be obtained using similar addition amounts.
[0108]
The shape of the electroconductive particles of the
present embodiment may be one or more shapes selected from
granular, acicular, or tabular shapes. The tungsten oxide
particles and composite tungsten oxide particles constituting
the electroconductive particles can be easily formed into
acicular shapes (e.g., refer to FIGS. 4A and 4B showing SEM
Images of the acicular crystals of Wi8O49 (W2.72) of Example 1
described later), and better electroconductive characteristics
can be obtained when a dispersed body is formed. The abovedescribed
tungsten bronze can form tabular shapes (e.g., refer
to FIGS. 6A and 6B showing SEM images of the tabular crystals
of hexagonal tungsten bronze Cso.3sWO3 (W2.72) of Example 4
described later), and is effective for obtaining excellent
electroconductive characteristics when a dispersed body is
formed.
[0109]
The electroconductive particles of the present invention
do not require the use of expensive starting materials such as
In and noble metals in comparison with the case in which ITO
particles and noble metal particles are used. Therefore, the
visible light transmitting particle-dispersed electrical
conductor described below can be obtained at low cost.
[0110]
2. Method for manufacturing electroconductive particles
The electroconductive particles composed of a tungsten
oxide expressed by the general formula WyOz (where W is
tungsten, O is oxygen, and 2.2 a z/y s: 2.999), and/or the
electroconductive particles composed of a composite tungsten
oxide expressed by the general formula MxWyOz (where M is one
or more elements selected from H, He, alkali metals, alkalineearth
metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co,
Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge,
Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be,
Hf, Os, Bi, and I; W is tungsten; O is oxygen; 0.001 ^ x/y s;
1.1; and 2.2 * z/y s; 3.0) are obtained by heat treating a
tungsten compound (hereinafter referred to as "tungsten
compound starting material"), which is a starting material of
the electroconductive particles, in an atmosphere of an inert
gas and/or reducing gas. The electroconductive particles can
be obtained at low cost by using a simple method.
[0111]
Preferably used as the tungsten oxide starting material
of the above-described electroconductive particles is one or
more compounds selected from tungsten trioxide; tungsten
dioxide; tungsten oxide hydrate; tungsten hexachloride;
ammonium tungstate; tungsten oxide; tungsten oxide hydrate
obtained by dissolving tungsten hexachloride in an alcohol and
then drying the solution; tungsten oxide hydrate obtained by
dissolving tungsten hexachloride in an alcohol, adding water
to the solution to form a precipitate, and drying the
precipitate; a tungsten compound obtained by drying an aqueous
solution of ammonium tungstate; and a metal tungsten powder.
[0112]
When the tungsten oxide electroconductive particles are
produced, it is further preferable from the standpoint of
facilitating the production step to use tungsten trioxide,
tungsten oxide hydrate powder, tungsten oxide, or an aqueous
solution of ammonium tungstate. When the composite tungsten
oxide electroconductive particles are produced. It Is
preferable to use an aqueous solution of ammonium tungstate or
an aqueous solution of tungsten hexachloride from the
standpoint of producing a uniform mixture of the elements when
the tungsten compound starting materials are in a solution.
When the starting materials are not in a liquid state,
tungsten oxide or the like is preferably used.
[0113]
The tungsten compound starting materials are heat treated
at a temperature ranging from 100° C or greater to 850° C or
less in an atmosphere of a reducing gas, and subsequently heat
treated as required at a temperature ranging from 550° C or
greater to 1,200'C or less in an atmosphere of an inert gas,
whereby the tungsten oxide particles and composite tungsten
oxide particles having the above-described diameters (from 1
nm or greater to 10,000 \m or less) can be obtained.
[0114]
The heat treatment conditions for manufacturing tungsten
oxide particles are described below.
The heat treatment conditions in a reducing atmosphere
preferably Include, first, heat treating the tungsten compound
starting material in a reducing atmosphere of from 100°C or
greater to 850°C or less. A temperature of 100" C or greater
is preferred because the reductive reaction progresses more
adequately. A temperature of 850° C or less is preferred
because reduction does not progress excessively. The reducing
gas is not particularly limited, but H2 is preferred. When H2
is used as the reducing gas, H2 as a component of the reducing
atmosphere is preferably present in a volume ratio of 0.1% or
greater and, more preferably, in a volume ratio of 2% or
greater. Reduction can progress with good efficiency when H2 is
present in a volume ratio of 0.1% or greater.
[0115]
Next, the resulting particles may be further subjected to
heat treatment as required at a temperature ranging from 550°C
or greater to 1,200°C or less in an atmosphere of an inert gas
in order to improve the crystallinity and to remove adsorbed
reducing gas. The heat treatment in the atmosphere of an
inert gas is preferably carried out at 550°C or greater.
Tungsten compound starting materials that are heat treated at
550°C or greater exhibit sufficient electrical conductivity.
Ar, N2, or another inert gas may be used.
A tungsten oxide expressed by the general formula WyOz
that satisfies the range 2.2 £ z/y * 2.999 and has a Magneli
phase can be obtained.
[0116]
The heat treatment conditions for manufacturing composite
tungsten oxide particles are as follows.
A powder is manufactured by mixing compounds or simple
substances composed of the above-described tungsten compound
starting material and the element M (where M is one or more
elements selected from H, He, alkali metals, alkaline-earth
metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh,
Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn,
Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf,
Os, Bi, and I); or a powder is obtained by mixing a solution
or liquid dispersion of the tungsten compound starting
material and a solution or liquid dispersion of the compound
containing the element M and drying the solution. The mixture
ratio of the element M and the tungsten oxide starting
material is one in which the composition ratio of element M
and tungsten in the composite tungsten oxide is a prescribed
value that satisfies the range 0.001 s x/y s; 1 when the
composite tungsten oxide has the formula MxWyOz.
[0117]
Here, the starting materials are preferably mixed in a
solution in order to manufacture a tungsten compound starting
material in which the components are uniformly mixed at the
molecular level. A tungsten compound starting material that
has an element M is preferably soluble in water, an organic
solvent, or another solvent. Examples include M-containing
tungstates, chlorides, nitrates, sulfates, oxalates, oxides,
carbonates, and hydroxides, but no limitation is imposed
thereby, and a tungsten compound capable of forming a solution
is preferred. Since evaporating a solvent from a dissolved
state is complicated from the commercial standpoint, the
mixing and reaction may be carried out in a solid state. In
this case, the material that is used is preferably a carbonate
or a hydroxide of an element M and tungstic acid because the
emission of toxic gases or the like from the starting material
compounds is not preferred from the commercial standpoint.
[0118]
The heat treatment conditions are the same as the heating
conditions for manufacturing the tungsten oxide particles
described above. The following heat treatment conditions can
be proposed to manufacture a composite tungsten oxide having
good crystallinity. However, the heat treatment conditions
differ depending on the starting material and the type of
desired compound, and are not limited by the following methods,
When manufacturing a composite tungsten oxide having good
crystallinity, the heat treatment conditions are preferably
high, and the reduction temperature differs depending on the
starting material and the temperature of H2 during reduction,
but 600°C to 850°C is preferred. The heat treatment
temperature maintained in the subsequent inert gas environment
is preferably 700°C to 1,200°C.
[0119]
3. Visible light transmitting particle-dispersed
electrical conductor
The electroconductive particles of the present embodiment
can be provided with visible-light transmittance by
controlling the composition, grain size, and shape of the
electroconductive particles as described above, and a visible
light transmitting particle-dispersed electrical conductor can
be formed at low cost in comparison with the case in which ITO
particles and noble metal particles are used by bringing
together and causing contact between a plurality of
electroconductive particles to form an electrical conductor.
A method for applying these electroconductive particles
entails suitably dispersing the electroconductive particles in
a medium by using any of the dispersing methods described
below, and forming an electrical conductor on a desired base
material. This method entails dispersing electroconductive
particles baked at a high temperature in advance in a base
material, or binding the particles to the base material
surface using a binder, whereby application can be made to
resins and other base materials that have a low heatresistance
temperature. An electrical conductor can be
manufactured at low cost without the use of a vacuum apparatus
or other bulky equipment.
[0120]
The visible light transmitting particle-dispersed
electrical conductor of the present embodiment can be formed
into the shape of a film, and the electroconductive particles
pre-baked at a high temperature can be bonded and formed on
the surface of a base material by using a binder. No
limitation is imposed by this binder, but a transparent resin
or a transparent dielectric is preferred.
[0121]
(a) Method for dispersing electroconductive particles in
a medium and forming a film on the surface of a base material
A visible light transmitting particle-dispersed
electrical conductor film in which electroconductive particles
are dispersed in a medium can be formed by suitably dispersing
the electroconductive particles of the present embodiment in a
medium, adding a resin medium as required, applying the
resulting dispersion to the surface of a base material, and
vaporizing the solvent to cure the resin by a prescribed
method. The coating method is not particularly limited as
long as the resin containing the electroconductive particles
can be uniformly applied to the surface of a base material.
Examples include bar coating, gravure coating, spray coating,
and dip coating.
[0122]
The medium may be selected from, e.g., a UV-curable resin,
a thermosetting resin, an electron beam-curable resin, a room
temperature-curable resin, a thermoplastic resin, or another
resin in accordance with the purpose. Specific examples of
the resin Include polyethylene resin, polyvinyl chloride resin,
polyvinylidene chloride resin, polyvinyl alcohol resin,
polystyrene resin, polypropylene resin, ethylene-vinyl acetate
copolymer, polyester resin, polyethylene terephthalate resin,
fluorine resin, polycarbonate resin, acrylic resin, and
polyvinyl butyral resin. A binder that uses a metal alkoxide
may also be used as the medium. Typical examples of metal
alkoxides include those of Si, Ti, Al, and Zr. Binders that
use these metal alkoxides may be subjected to hydrolysis and
then heated to form an oxide film.
[0123]
A visible light transmitting particle-dispersed
electrical conductor film in which electroconductive particles
are dispersed on a base material surface can be formed by
dispersing the electroconductive particles of the present
embodiment in a suitable solvent, applying the resulting
dispersion to the surface of a base material, and vaporizing
the solvent. However, since the electrical conductor film by
itself has poor strength, a solution containing a resin or the
like is preferably applied to the electrical conductor film,
and the solvent is vaporized to form a protective film. The
coating method is not particularly limited as long as the
resin containing the electroconductive particles can be
uniformly applied to the surface of a base material. Examples
include bar coating, gravure coating, spray coating, and dip
coating.
[0124]
The method for dispersing the electroconductive particles
is not particularly limited, and ultrasonic irradiation, a
bead mill, a sand mill, or the like can be used, for example.
Additives may be added to obtain a uniform dispersed body, and
the pH may be adjusted.
[0125]
The shape of the base material is not limited, and the
base material may be formed in the shape of a film or board as
desired. PET, acryl, urethane, polycarbonate, polyethylene,
ethylene-vinyl acetate copolymer, vinyl chloride, fluorine
resin, or the like may be used as the transparent base
material in accordance with the intended purpose. Apart from
resins, glass may be used.
[0126]
(b) Method for dispersing particles in a base material
Another method that may be used for applying the
electroconductive particles of the present embodiment is to
disperse the electroconductive particles in a base material.
In order to disperse the electroconductive particles in a base
material, the electroconductive particles may be allowed to
permeate from the surface of the base material, or the
temperature of the electroconductive particles may be
increased above the melting temperature of the base material,
and the particles may then be melted and mixed with resin.
The resulting resin containing the electroconductive particles
may be molded into a film or a board by a prescribed method
and used as an electroconductive material.
[0127]
An example of a method for dispersing the
electroconductive particles in a PET resin entails mixing PET
resin and a liquid dispersion of the electroconductive
particles, vaporizing the dispersion solvent, thereafter
heating the material to about 300°C, which is the melting point
of PET resin, to melt and mix the PET resin, and then cooling
the material to produce a PET resin in which the
electroconductive particles are dispersed.
[0128]
(4) Particle shape
The electroconductive particles of the tungsten oxide and
the electroconductive particles of the composite tungsten
oxide may be formed into acicular crystals such as those shown
in FIG. 4 by using a suitable heat treatment. Acicular
crystals have the effect of improving the electrical
conductivity of the visible light transmitting particledispersed
electrical conductor film in comparison with very
fine-grained particles. The reason for this is that the
resistance of the film is degraded in comparison with a bulk
configuration due to the contact resistance between the
particles, but when acicular crystals are used in the visible
light transmitting particle-dispersed electrical conductor
film, each of the acicular crystals becomes a current-carrying
path. Therefore the contact resistance is low in comparison
with cases in which the very fine-grained particles are linked
to each other, and electron transport can be carried out with
good efficiency. Accordingly, electrical conductivity is
improved.
[0129]
The electroconductive particles of hexagonal tungsten
bronze, which are electroconductive particles of a composite
tungsten oxide, can be formed into the tabular crystals shown
in FIG. 6. Tabular crystals are particularly easy to form
when the element M is added in an amount that is greater than
0.33. The resulting tabular crystals readily improve
electrical conductivity because the surface resistance per
unit surface area can be reduced in comparison with dispersed
nan opar tides.
[0130]
However, the acicular and tabular crystals described
above have about the same size, light is therefore easily
scattered, and transparency may be reduced. When transparency
is to be improved, the acicular and tabular crystals must be
pulverized into very small shapes, and the particle shapes are
preferably changed in accordance with the intended purpose.
The pulverizing method may be an ordinary pulverizing method.
[0131]
5. Optical characteristics of the visible light
transmitting particle-dispersed electrical conductor
The optical characteristics of the visible light
transmitting particle-dispersed electrical conductor of the
present embodiment were measured using a spectrophotometer (U-
4000 manufactured by Hitachi Ltd.), and the visible-light
transmittance was calculated (based on JIS R3106).
[0132]
FIG. 2 shows, as an example of the transmittance
measurement results, a transmission profile of a visible light
transmitting particle-dispersed electrical conductor formed
from WiaO49 electroconductive particles. FIG. 2 is a graph in
which the wavelength of the transmitted light is plotted along
the horizontal axis, and the transmittance (%) of the light is
plotted along the vertical axis. It is apparent from FIG. 2
that a visible light transmitting particle-dispersed
electrical conductor formed from the Wi8O49 electroconductive
particles transmits light having a wavelength of 380 nm to 780
run, which is the visible light region (e.g., the transmittance
of visible light having a wavelength of 500 nm is 60%).
[0133]
FIG. 3 shows a transmission profile of Cs0.33WO3 as an
example of a transmission profile of a visible light
transmitting particle-dispersed electrical conductor formed
from electroconductive particles composed of hexagonal
composite tungsten oxide. FIG. 3 is a graph in which the
wavelength of the transmitted light is plotted along the
horizontal axis, and the transmittance (%) of the light is
plotted along the vertical axis. It is apparent from FIG. 3
that a visible light transmitting particle-dispersed
electrical conductor composed of Cs0.33WO3 transmits light
having a wavelength of 380 nm to 780 nra, which is the visible
light region, and transmittance in the visible light region is
excellent.
[0134]
The visible light transmitting particle-dispersed
electrical conductor has industrial utility in that a visible
light transmitting particle-dispersed electrical conductor can
be formed at low cost by coating or the like without the use
of sputtering, vapor deposition, or ion-plating, as well as
chemical vapor deposition (CVD) or another dry method vacuum
deposition method that uses a vacuum apparatus or other bulky
equipment.
[0135]
[2] Transparent electroconductive film and method for
manufacturing the same, transparent electroconductlve article,
and Infrared-shielding article
[0136]
The best mode for carrying out the present invention is
described below.
Generally, tungsten trioxide (WO3) does not have effective
conduction electrons and therefore has no electrical
conductivity, although visible light is transmitted. The
inventors discovered that by using the backbone structure of
tungsten trioxide, a tungsten oxide in which conduction
electrons are generated in the WO3 by reducing the ratio of
oxygen to tungsten to less than 3, or a composite tungsten
oxide in which conduction electrons are generated by adding
positive ions, can be provided with electrical conductivity by
way of these conduction electrons while simultaneously
transmitting visible light.
[0137]
Elements A described above can be used as elements having
the same properties as the above-described tungsten. Similar
to tungsten oxide, oxides of these elements A have a so-called
tungsten bronze structure composed of electropositive elements
in the crystals. As a result, the inventors also discovered
that even when some tungsten sites are substituted with an
element A and are composited with tungsten oxide, or an
electroconductive film is formed having the so-called tungsten
bronze structure by using an element A in place of tungsten,
the film can be provided with electrical conductivity by way
of these conduction electrons while simultaneously
transmitting visible light.
[0138]
The inventors also discovered that the transparent
electroconductive film can be obtained using a simple method
in which a solution composed of a tungsten compound, which is
a starting material of the subsequently described tungsten
oxide and/or composite tungsten oxide, or a solution composed
of an element A compound is used as the starting material
solution, the starting material solution is applied to a base
material, and the base material coated with the starting
material solution is heat treated in an atmosphere of a
reducing gas and/or inert gas to manufacture the transparent
electroconductive film.
[0139]
1-(A). Tungsten oxide and composite tungsten oxide
The transparent electroconductive film of the present
embodiment includes a tungsten oxide expressed by the general
formula WyOz (where W is tungsten, O is oxygen, and 2.2 £ z/y
£ 2.999), and/or a composite tungsten oxide expressed by the
general formula MxWyOz (where M is one or more elements
selected from H, He, alkali metals, alkaline-earth metals,
rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni,
Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb,
B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi,
and I; W is tungsten; O is oxygen; 0.001 £ x/y s 1, and 2.2s:
z/y s 3.0), wherein the maximum transmittance in the region of
400 run or greater to 780 nm or less ranges from 10% or greater
to less than 92%, and the surface resistance of the film is
1.0 x 1010 Q/square or less.
[0140]
In the tungsten oxide expressed by the general formula
WyOz (where W is tungsten, O is oxygen, and 2.2 * z/y s 2.999),
the tungsten/oxygen composition range is one in which the
composition ratio of oxygen to tungsten is less than 3, and
the range 2.2 s z/y s 2.999 is preferred when the transparent
electroconductive film have the formula WyOz. When the value
of z/y is 2.2 or greater, formation of an unwanted WO2 crystal
phase in the film can be avoided and the material can be
provided with chemical stability, and can therefore be used as
an effective transparent electroconductive film. When the
value of z/y is 2.999 or less, the required amount of free
electrons can be generated to produce a transparent
electroconductive film.
[0141]
In the transparent electroconductive film of the present
Invention, the maximum transmittance measured in the
wavelength region of 400 run or greater to 780 nm or less
ranges from 10% or greater to less than 92%. When the maximum
transmittance is 10% or greater, the range of application in
visible light-transmitting applications is broad. When the
maximum transmittance is 92% or less, the technical aspects of
manufacturing are facilitated. The optical measurements were
carried out based on JIS R3106 (light source: A light) to
calculate the visible-light transmittance.
[0142]
The surface resistance of the transparent
electroconductive film of the present invention is 1.0 x 1010
Q/sguare or less. When the surface resistance is as described
above, the electroconductive film can be advantageously used
in a broad range of applications. The surface resistance was
measured using a surface resistance measuring device (Loresta
MP MCP-T350) manufactured by Mitsubishi Chemical.
[0143]
In the transparent electroconductive film of the present
embodiment, the tungsten oxide preferably has a Magneli phase
having a composition ratio expressed by the general formula
WyOz (where W is tungsten, O is oxygen, and 2.45 s z/y s
2.999).
[0144]
Here, the electrical conduction mechanism of the
transparent electroconductive film of the present invention is
briefly described.
Tungsten trioxide has an octahedral structure composed of
WO6, and may be regarded as a single unit. W atoms are
positioned in the octahedral structure, and oxygen is
positioned at the apexes of the octahedral structure. In all
octahedral structures, the apexes are shared with an adjacent
octahedral structure. In this case, conduction electrons are
not present in the structure. On the other hand, the Magneli
phase expressed by WO2.9 or another composition ratio is a
structure in which the octahedral structure of WO6 shares edges
and apexes in an orderly fashion. Wi8O49 (WO2.?2) having the
structure shown in FIG. 1(A) has an orderly structure in which
the octahedral structure of WO6 and the decahedral structure of
WOio as a single unit share edges and apexes. Tungsten oxide
having such a structure is believed to be provided with
electrical conductivity via the contribution of electrons
released by oxygen as conduction electrons.
[0145]
The above-described structure of tungsten trioxide
produces conduction electrons in a completely uniform,
nonuniform, or amorphous structure, and electroconductive
characteristics can be obtained.
[0146]
Conduction electrons are generated in the WO3 and
electrical conductivity is obtained by adding an element M
(where M is one or more elements selected from H, He, alkali
metals, alkaline-earth metals, rare earth elements, Mg, Zr, Cr,
Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga,
In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V,
Mo, Ta, Re, Be, Hf, Os, Bi, and I) to the tungsten trioxide
(WO3). In other words, the ranges are preferably 0.001 £ x/y £
1, and 2.2 z z/y a 3.0 in a composite tungsten oxide expressed
by the general formula MxWyOz (where M is one or more elements
selected from H, He, alkali metals, alkaline-earth metals,
rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni,
Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb,
B, F, P. S. Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi,
and I; W is tungsten; 0 is oxygen; 0.001 2 x/y s 1, and 2.2 £
z/y a 3.0).
[0147]
When the above-noted ranges are satisfied, good
electrical conductivity is obtained by the generation of
conduction electrons. In the particular case that the ratio
(z/y) of O to W is 2.2 or greater, application as a lighttransmitting
film can be facilitated without increasing light
absorption in the visible light region, and such a situation
is preferred.
[0148]
The composite tungsten oxide expressed by the formula
MxWyOz preferably has an amorphous structure, or a cubic,
tetragonal, or hexagonal tungsten bronze structure.
The term "cubic structure" used in this specification is
used as a representative of tungsten bronze structures
classified as a cubic tungsten bronze structure type or a
perovskite tungsten bronze structure type in the general
classification of the tungsten bronze structure. The term
"tetragonal structure" used in this specification is used as a
representative of the tungsten bronze structures classified as
a tetragonal tungsten bronze structure type in the general
classification of the tungsten bronze structure. The term
"hexagonal structure" used in this specification is used as a
representative of the tungsten bronze structures classified as
a hexagonal tungsten bronze structure type in the general
classification of the tungsten bronze structure.
[0149]
With this composite tungsten oxide, the element M is
positioned in the gaps formed between shared apexes of an
octahedral structure, as shown in FIGS. IB to ID. It is
believed that conduction electrons are produced by the
addition of the elements M. The structure of a composite
tungsten oxide is typically cubic, tetragonal, or hexagonal,
and these structures are shown in FIGS. IB, 1C and ID,
respectively. These composite tungsten oxides have a
structure-based upper limit to the amount of addition element,
and the maximum addition amount of the element M per mole of W
is as follows: 1 mol in the case of a cubic system, about 0.5
mol in the case of a tetragonal system (this varies depending
on the addition amount, but 0.5 mol can be easily produced on
a commercial scale), and 0.33 mol in the case of a hexagonal
system. However, these structures are difficult to define in
a simple manner, and the range of maximum addition amounts of
the addition element M described above is an example that
particularly shows a basic range, and this Invention is not
limited to this range. Several types of structures may be
adopted in the crystal structure by compositing materials.
The above-described structure is a representative structure,
and no limitation is imposed by the structure.
[0150]
In a composite tungsten oxide, the optical
characteristics vary depending on the above-described
structure. Hexagonal systems in particular tend to have a
72
light absorption region based on conduction electrons in the
near-infrared region having longer wavelengths, and absorption
in the visible light region is also low. Next, tetragonal
systems and cubic systems tend to absorb light having shorter
wavelengths by means of conduction electrons, and absorption
in the visible light region is also high. Accordingly, a
composite tungsten oxide, which has a hexagonal structure, is
preferred for the above-stated reasons as the transparent
electroconductive film capable of transmitting more visible
light. However, as long as the oxide has the basic
configuration described above, electrical conductivity and
infrared-shielding characteristics can be obtained even if the
structure is an amorphous structure.
[0151]
It is commonly known that a hexagonal system is formed
when an element M having a large ion radius is added to a
composite tungsten oxide. Specifically, when any of the
elements Cs, K, Rb, Tl, Ba, In, Li, Ca, Sr, Fe, and Sn are
added, a hexagonal system is readily formed, and such a
situation is preferred. However, as long as the added element
M is present in the gaps of the hexagonal structure, as shown
in FIG. ID, for example, a WO6 unit can be formed using an
element other than those noted above, and no limitation is
imposed by these elements. Also, a composite tungsten oxide
having these hexagonal structures may be a uniform crystal
structure or an irregular crystal structure.
[0152]
In this case, It Is possible use both methods. I.e., to
limit the above-described oxygen content and to add an element
M for generating conduction electrons to the tungsten trioxide
(WO3). Also, when the transparent electroconductive film
described above is used as an infrared-shielding film, a
material that is suitable for the time and purpose, e.g., an
element M, may be selected.
[0153]
1-(B). Composite oxide nanoparticles that Include element
A
In addition to the tungsten oxide and composite tungsten
oxide described in 1-(A), there is also a composite oxide
expressed by the general formula MEAGW(i-G)Oj (where M is one or
more elements selected from H, He, alkali metals, alkalineearth
metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co,
Rh, Ir, Ni, Pd. Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge,
Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be,
Hf, Os, Bi, and I; A is one or more elements selected from Mo,
Nb, Ta, Mn, V, Re, Pt, Pd, and Ti; W is tungsten; O is oxygen;
0 the result is a composite oxide in which tungsten is not used
and that is primarily composed of an element A.
[0154]
Since effective free electrons are generally not present
in WO3 or in MoO3, Nb2Os, Ta2O5, V2O5, TiO2, and MnO2, these
compounds have no or minimal electrical conductivity, and have
no or minimal absorption (reflection) of light in the nearinfrared
region by conduction electrons. However, when
element M is added to these substances, and composite tungsten
oxide nanoparticles expressed by the general formula MEAGW(i-G)Oj
(where M is one or more elements selected from H, He, alkali
metals, alkaline-earth metals, rare earth elements, Mg, Zr, Cr,
Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga,
In, Tl, Si. Ge, Sn, Pb. Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V.
Mo, Ta, Re, Be, Hf, Os, Bi, and I; A is one or more elements
selected from Mo, Nb, Ta, Mn, V, Re, Pt, Pd, and Ti; W is
tungsten; O is oxygen; 0 are used, the element M releases conduction electrons in the
oxide structure of W or the element A, and the element M
itself acts as a positive ion.
[0155]
The released conduction electrons have the effect of
absorbing (reflecting) light in the near-infrared region, and
contribute to the electrical conductivity of the composite
oxide nanoparticles. It is apparent that PtOx, PdOx, ReO3, and
the like exhibit electrical conductivity even without the
addition of an element M, and adding the element M further
Increases the number of conduction electrons and improves
conduction characteristics and absorption (reflection) in the
near-Infrared region.
[0156]
The matrix structure obtained using an element A,
tungsten, and oxygen may be constructed using oxygen and one
element selected from tungsten and an element A, or may be
constructed using oxygen and a plurality of elements. When an
element M is added to the gaps of a structure composed of
oxygen, tungsten, and the element A, conduction electrons are
generated, and this approach is effective for conduction
characteristics and near-infrared absorption.
[0157]
In the formula MEAGW(i-G)Oj, the range of E is preferably 0
0, conduction electrons are generated by
the element M, and effective near-infrared absorption and
conduction characteristics are demonstrated. If the value of
E is 1.2 or less, the generation of impurities contained in
the element M is avoided, degradation of the characteristics
can be prevented, and such a situation is therefore preferred.
[0158]
In the formula MEAGW(i-6)Oj, the range of 6 is preferably 0
conduction electrons are generated and effective near-infrared
absorption and conduction characteristics are demonstrated.
An element A other than tungsten is present in the composite
oxide, whereby the optical characteristics of the composite
oxide can be varied and conventionally unavailable features
can otherwise be demonstrated. Therefore, G is preferably
greater than 0. The preferred addition amount of the element
A varies in accordance with the intended use, but 1 or less is
preferred. When G s; 1, impurities contained in the element A
are not generated due to the presence of excessive element A,
and degradation of the composite oxide characteristics can
therefore be prevented.
[0159]
The case of G When the composite oxide nanoparticles of the composition
MEAGW(i-G)Oj described above have a hexagonal crystal structure,
the transmission characteristics of the composite oxide
nanoparticles with respect to visible light are improved and
the absorption characteristics of light in the near-Infrared
region are also improved. This will be described with
reference to FIG. ID, which is a schematic diagram of the
hexagonal structure. In FIG. ID, six octahedrons formed by W
(or an element A) O6 units are brought together and provided
with hexagonal gaps. An element M is disposed in the gaps,
constituting a single unit. A large number of these units are
brought together to form a hexagonal crystal structure. This
structure is referred to as a so-called tungsten bronze
structure.
[0160]
In order to achieve the effect of improving transmission
characteristics in the visible light region and improving
absorption characteristics in the near-infrared region, the
composite oxide nanoparticles should at least contain some of
the unit structures described in FIG. ID (a structure in which
six octahedrons formed by W (or an element A) O6 units are
brought together and provided with hexagonal gaps, and element
M is disposed in the gaps), and the tungsten oxide composite
nanoparticles may be either crystalline or amorphous.
[0161]
Introducing positive ions of the element M into the
hexagonal gaps is preferred because transmission
characteristics of visible light are improved in comparison
with other crystal structures, and absorption characteristics
of light in the near-infrared region are also improved. From
the standpoint of electroconductive applications, since the
absorption of visible light by the composite oxide
nanoparticles is low, visible-light transmittance is reduced
only slightly even when a large amount of the nanoparticles is
used, and this approach is effective for improving electrical
conductivity in a visible-light-transmitting electroconductive
material. Generally, when the element M having a large ion
radius is added, a hexagonal crystal is formed. Specifically,
when one or more elements selected from Cs, Rb, K, Tl, In, Ba,
Li, Ca, Sr, Fe, and Sn are added, a hexagonal system is
readily formed. As long as an element M is present in the
hexagonal gaps formed by the W (or element A) O6 units, another
element may naturally be used and no limitation is imposed by
the element.
[0162]
When the composite tungsten oxide nanoparticles having a
hexagonal structure have a uniform crystal structure in the
tungsten bronze structure, the addition amount of the element
M is preferably 0.2 or more and 0.5 or less, and more
preferably about 0.33. It is believed that the element M is
inserted into all of the hexagonal gaps in a tungsten bronze
structure by setting the addition amount of the element M to
be 0.33. In this case, the tungsten sites of the tungsten
bronze structure are substituted with the element A, and the
bronze structures of tungsten and element A may be present
together or may be independent of each other.
[0163]
In addition to the above-described hexagonal tungsten
bronze structure, tetragonal and cubic tungsten bronze
structures are also effective as infrared-shielding materials.
The absorption position of light in the near-infrared region
tends to vary depending on the crystal structure. The
absorption position of a cubic structure has a greater
tendency to move toward the longer wavelengths than does a
tetragonal structure, and a tetragonal structure has a greater
tendency to do so than a hexagonal structure. Also, hexagonal
structures have the lowest absorption characteristics for
visible light, and tetragonal and cubic structures have
increasingly greater absorption characteristics in the
indicated order. Therefore, a hexagonal tungsten bronze
structure is preferably used in applications in which more
visible light is to be transmitted and more light in the nearinfrared
region is to be shielded. In this case, the tungsten
sites of the tungsten bronze structure may be substituted
using an element A, or a bronze structure of an element A may
be also present. However, the tendencies of the optical
characteristics described above will vary depending on the
type and amount of added elements. The optimal solution may
therefore be determined by experimentation, and the present
invention is not limited thereby.
[0164]
The case of G - 1 is described next.
When G - 1 in composite oxide nanoparticles having a
composition expressed by the formula MEAGW(i-G)Oj described above,
the composition becomes MeAOj and does not contain tungsten.
However, electrons are generated when an element M is added
even in a material that does not include tungsten. Conduction
characteristics can be provided by the generation of
conduction electrons via the same mechanism as the case of
MEAoWd-GjOj (where G near-Infrared region is shielded. Therefore, the composition
can be handled in the same manner as in the case in which
tungsten is included in the composition (when G [0165]
2-(A). Method for manufacturing transparent
electroconductive film that uses tungsten oxide, and method
for manufacturing transparent electroconductive film that uses
composite tungsten oxide
A transparent electroconductive film composed of a
tungsten oxide expressed by the general formula WyOz (where W
is tungsten, O is oxygen, and 2.2 £ z/y £ 2.999), and/or a
composite tungsten oxide expressed by the general formula
MxWyOz (where M is one or more elements selected from H, He,
alkali metals, alkaline-earth metals, rare earth elements, Mg,
Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd,
Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se. Br, Te, Ti,
Mb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; W is tungsten; O is
oxygen; 0.001 * x/y j£ 1, and 2.2 s z/y ^ 3.0) can be obtained
by using, as a starting tungsten material solution, a solution
that contains a tungsten compound, which is a starting
material of the tungsten oxide and/or the composite tungsten
oxide; applying the tungsten compound starting material
solution; and thereafter heat treating the base material
coated with the tungsten compound starting material solution,
in an atmosphere of an inert gas and/or reducing gas.
[0166]
A preferable approach is to add a surfactant to the
starting material solution and then apply the solution to a
base material to uniformly form a thin film on a base material.
Nonionic, anionic, cationic, amphoteric, or other surfactants
may be used. In the particular case that an aqueous solution
such as that of ammonium metatungstate is used, the surface
tension of the water is considerable. Therefore, a surfactant
must be added to reduce the surface tension so that the
solution can be uniformly applied to a base material.
[0167]
One or more solutions selected from aqueous solutions of
ammonium tungstate and solutions obtained by dissolving
tungsten hexachlorlde in an alcohol are preferably used as the
tungsten compound starting material solution. If the starting
material is a tungsten starting material, the material is
easily dissolved in water or alcohol, and coating on a base
material can be easily performed using an inexpensive coating
method.
[0168]
Preferably used as the tungsten compound starting
material solution of the transparent electroconductive film is
a mixed solution composed of a tungsten compound starting
material solution (one or more solutions selected from aqueous
solutions of ammonium tungstate and solutions obtained by
dissolving tungsten hexachloride in an alcohol, or a solution
obtained by adding a surfactant to this starting material) as
a composite tungsten oxide starting material solution and an
element M (where M is one or more elements selected from H, He,
alkali metals, alkaline-earth metals, rare earth elements, Mg,
Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Nl, Pd, Pt, Cu, Ag, Au, Zn, Cd,
Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti,
Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I).
[0169]
Examples of the starting material of the addition element
M include M-containing tungstates, chlorides, nitrates,
sulfates, oxalates, oxides, carbonates, and hydroxides, but no
limitation is imposed thereby as long as the material can form
a solution.
[0170]
The transparent electroconductive film of the present
embodiment may be obtained by applying a tungsten compound
starting material solution to a base material, and then heat
treating the material in an atmosphere of an inert gas
atmosphere and/or reducing gas. In this manner, when a
tungsten compound starting material solution is applied to a
base material, and the material is then heat treated in an
atmosphere of an inert gas atmosphere and/or reducing gas, the
heat treatment is preferably carried out in an atmosphere of a
reducing gas at a temperature ranging from 100° C or greater to
800°C or less, and then carried out as required in an
atmosphere of an inert gas at a temperature ranging from 550° C
or greater to 1,200"C or less. The reducing gas is not
particularly limited in this case, but H2 is preferred. When
Ha is used as the reducing gas, H2 as a component of the
reducing atmosphere is preferably present in a volume ratio of
0.1% or greater and, and more preferably in a volume ratio of
2% or greater. Reduction can progress with good efficiency
when Ha is present in a volume ratio of 0.1% or greater. N2 or
argon gas is used as the inert gas.
[0171]
The transparent electroconductive film of the present
embodiment may be formed by vapor deposition or sputtering,
and any manufacturing method may be used as long as the
resulting film is a tungsten oxide or a composite tungsten
oxide. When the transparent electroconductive film of the
present embodiment is obtained by sputtering or vapor
deposition, starting materials that are suitable for each
method may be used. For example, vapor deposition pellets and
a target suited for the desired transparent electroconductive
film composition may be used.
[0172]
2-(B). Method for manufacturing transparent
electroconductive film that uses composite tungsten oxide
nanoparticles that contain an element A
The composite oxide expressed by the general formula
MEAcWd-GjOj may be obtained by heat treating the starting
material in an atmosphere of an inert gas and/or reducing gas.
The starting material of element A and tungsten is not
particularly limited as long as tungsten or element A is
included. Examples that may be used Include one or more
compounds selected from oxides, hydrated oxides, chlorides,
ammonium salts, carbonates, nitrates, sulfates, oxalates,
hydroxides, peroxides, and simple metals. Organic compounds
or compounds containing two or more types of metal elements
(e.g., sodium tungstate) may also be used. An advantageous
commercial manufacturing method is one in which water or a
solvent are mixed using various types of salts.
[0173]
In the composite oxide nanoparticles expressed by the
general formula MEAoWd-oOj, the starting material of the
element M may include the element M, and the starting material
of the element A may include the element A. No particular
limitations are imposed. Preferred examples include one or
more compounds selected from chlorides, ammonium salts,
carbonates, nitrates, sulfates, oxalates, hydroxides, and
peroxides. Also, organic complexes, or compounds containing
two or more types of metal elements (e.g., sodium tungstate)
may be used. An advantageous commercial manufacturing method
is one in which Impurities are not produced during heat
reduction when carbonates, hydrates, or the like are used.
[0174]
The starting materials of the tungsten W, element A, and
element M that can form a solution (chlorides, nitrates, and
the like) are preferably formed into a solution and mixed to
obtain a starting material, whereby sufficient mixing can be
achieved.
[0175]
Here, the heat treatment condition maintained after the
starting material of the element M, as well as tungsten and
the starting material of the element A, have been mixed is
preferably 250°C or greater. A film obtained by heat
treatment at 250°C or greater has sufficient electrical
conductivity and near-infrared absorbency.
Ar, N2, or another inert gas may be used as the heat
treatment atmosphere. Ammonia or hydrogen gas may be used as
the reducing gas.
When hydrogen gas is used, hydrogen gas as a component of
the reducing atmosphere is preferably present in a volume
ratio of 0.1% or greater and, and more preferably in a volume
ratio of 1% or greater. Reduction can progress with good
efficiency when hydrogen gas is present in a volume ratio of
0.1% or greater.
[0176]
3. Transparent electroconductive article and infraredshielding
article
The transparent electroconductive film of the present
embodiment is formed on a base material to obtain a
transparent electroconductive article. The base material of
the transparent electroconductive film is not particularly
limited, but transparent glass and transparent resin film are
common base materials.
[0177]
The thickness of the transparent electroconductive film
of the present embodiment can be varied in accordance with the
intended use, but from 1 nm or greater to 5,000 nm or less is
preferred. If the film thickness is 1 nm or greater,
effective conduction characteristics can be achieved. If the
film thickness is 5,000 nm or less, the transmittance of
visible light is not reduced, and such a situation is
preferred.
[0178]
The transparent electroconductive film of the present
embodiment exhibits absorbency and reflectivity from the nearinfrared
to infrared regions by conductive electrons. The
film therefore has infrared- and near-infrared-shielding
functions, and is advantageous as a visible-light-transmitting
infrared-shielding article.
[0179]
[3] Infrared-shielding nanoparticle dispersion, infraredshielding
body, method for manufacturing infrared-shielding
nanoparticles, and Infrared-shielding nanoparticles
[0180]
The infrared-shielding nanoparticle dispersion of the
present embodiment is an infrared-shielding nanoparticle
dispersion obtained by dispersing Infrared-shielding
nanoparticles in a medium, and the infrared-shielding
nanoparticles Include composite oxide nanoparticles expressed
by the general formula MEAGW(i-G)Oj (where M is one or more
elements selected from H, He, alkali metals, alkaline-earth
metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh,
Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn,
Pb, Sb, B, F, P, S, Se, Br, Te. Ti, Nb, V, Mo, Ta, Re, Be, Hf,
Os, Bi, and I; A is one or more elements selected from Mo, Nb,
Ta, Mn, V, Re, Pt, Pd, and Ti; W is tungsten; O is oxygen; 0 E = s l . 2 ; 0 infrared-shielding nanoparticles of the present embodiment do
not contain tungsten when G «= 1, resulting in composite oxide
nanoparticles that are primarily composed of the element A.
[0181]
1. Composite oxide nanoparticles
Since effective free electrons are generally not present
in WO3 or in MoO3, Nb2O5, Ta2O5, V2O5, TiO2, and MnO2, these
compounds have no or minimal electrical conductivity, and have
no or minimal absorption (reflection) in the near-infrared
region due to conduction electrons. However, when an element
M is added to these substances, and composite tungsten oxide
nanoparticles expressed by the general formula MEAaWd-cjOj
(where M is one or more elements selected from H, He, alkali
metals, alkaline-earth metals, rare earth elements, Mg, Zr, Cr,
Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga,
In, Tl, Si, Ge, Sn, Pb, Sb. B. F, P, S, Se, Br, Te, Ti, Nb, V.
Mo, Ta, Re, Be, Hf, Os, Bi, and I; A is one or more elements
selected from Mo, Nb, Ta, Mn, V, Re, Pt, Pd, and Ti; W is
tungsten; O is oxygen; 0 are used, the element M releases conduction electrons in the
oxide structure of W or the element A, and the element M
Itself acts as a positive ion.
[0182]
The released conduction electrons have the effect of
absorbing (reflecting) light in the near-infrared region, and
contribute to the electrical conductivity of the composite
oxide nanopartlcles. It is apparent that PtOx, PdOx, ReO3, and
the like exhibit electrical conductivity even without the
addition of an element M, and adding an element M further
increases the number of conduction electrons and improves
conduction characteristics and absorption (reflection) in the
near-infrared region.
[0183]
The matrix structure obtained using an element A,
tungsten, and oxygen may be constructed using oxygen and one
element selected from tungsten and an element A, or may be
constructed using oxygen and a plurality of elements. When an
element M is added to the gaps of a structure composed of
oxygen, tungsten, and the element A, conduction electrons are
generated, and this approach is effective for conduction
characteristics and near-infrared absorption.
[0184]
89
In the formula MEAGW(i-G)Oj, the range of E is preferably 0
E £ 1.2. If E > 0, conduction electrons are generated by
the element M, and effective near-infrared absorption and
conduction characteristics are demonstrated. If the value of
E is 1.2 or less, the generation of impurities contained in
the element M is avoided, degradation of the characteristics
can be prevented, and such a situation is therefore preferred.
[0185]
In the formula MuAcWd-oOj, the range of G is preferably 0
conduction electrons are generated and effective near-infrared
absorption and conduction characteristics are demonstrated.
An element A other than tungsten is present in the composite
oxide, whereby the optical characteristics of the composite
oxide can be varied and conventionally unavailable features
can otherwise be demonstrated. Therefore, G is preferably
greater than 0 depending on the intended use. The preferred
addition amount of the element A varies in accordance with the
Intended use, but 1 or less is preferred. When G s 1,
impurities contained in the element A are not generated due to
the presence of excessive element A, and degradation of the
composite oxide characteristics can therefore be prevented.
[0186]
The case of G When the composite oxide nanoparticles of the composition
MEAGW(i-G)Oj described above have a hexagonal crystal structure,
the transmission characteristics of the composite oxide
nanoparticles with respect to visible light are improved and
the absorption characteristics of light in the near-infrared
region are also improved. This will be described with
reference to FIG. 10, which is a schematic diagram of the
hexagonal structure. In FIG. 10, six octahedrons formed by W
(or an element A) O6 units are brought together and provided
with hexagonal gaps, wherein W is Indicated by the reference
numeral 1. An element M, indicated by the reference numeral 2,
is disposed in the gaps, constituting a single unit. A large
number of these units are brought together to form a hexagonal
crystal structure. This structure is referred to as a socalled
hexagonal tungsten bronze structure.
[0187]
In order to achieve the effect of improving transmission
characteristics in the visible light region and improving
absorption characteristics in the near-infrared region, the
composite oxide nanoparticles should at least contain some of
the unit structures described in FIG. 10 (a structure in which
six octahedrons formed by W (or an element A) O6 units are
brought together and provided with hexagonal gaps, and element
M is disposed in the gaps), and the composite oxide
nanoparticles may be either crystalline or amorphous.
[0188]
Introducing positive ions of the element M into the
hexagonal gaps is preferred because transmission
characteristics of visible light are improved in comparison
with other crystal structures, and absorption characteristics
of light in the near-infrared region are also improved. From
the standpoint of electroconductive applications, since the
absorption of visible light by the composite oxide
nanopartides is low, visible-light transmittance is reduced
only slightly even when a large amount of the nanoparticles is
used, and this approach is effective for improving electrical
conductivity in a visible-light-transmitting electroconductive
material. Generally, when the element M having a large ion
radius is added, a hexagonal crystal is formed. Specifically,
when one or more elements selected from Cs, Rb, K, Tl, In, Ba,
Li, Ca, Sr, Fe, and Sn are added, a hexagonal system is
readily formed. As long as an element M is present in the
hexagonal gaps formed by the W (or element A) 06 units, another
element may naturally be used and no limitation is imposed by
the element.
[0189]
When the composite tungsten oxide nanoparticles having a
hexagonal crystal structure have a uniform crystal structure
in the tungsten bronze structure, the addition amount of the
element M is preferably 0.2 or more and 0.5 or less, and more
preferably about 0.33. It is believed that the element M is
inserted into all of the hexagonal gaps in a tungsten bronze
structure by setting the addition amount of the element M to
be 0.33. In this case, the tungsten sites of the tungsten
bronze structure are substituted with the element A, and the
bronze structures of tungsten and element A may be present
together or may be independent of each other.
[0190]
In addition to the above-described hexagonal tungsten
bronze structure, tetragonal and cubic tungsten bronze
structures are also effective as infrared-shielding materials.
The absorption position of light in the near-infrared region
tends to vary depending on the crystal structure. The
absorption position of a cubic structure has a greater
tendency to move toward the longer wavelengths than does a
tetragonal structure, and a tetragonal structure has a greater
tendency to do so than a hexagonal structure. Also, hexagonal
structures have the lowest absorption characteristics for
visible light, and tetragonal and cubic structures have
increasingly greater absorption characteristics in the
Indicated order. Therefore, a hexagonal tungsten bronze
structure is preferably used in applications in which more
visible light is to be transmitted and more light in the nearinfrared
region is to be shielded. In this case, the tungsten
sites of the tungsten bronze structure may be substituted
using an element A, or a bronze structure of an element A may
be also present. However, the tendencies of the optical
characteristics described above will vary depending on the
type and amount of added elements. The optimal solution may
therefore be determined by experimentation, and the present
invention is not limited thereby.
[0191]
The case of G - 1 is described next.
When G = 1 in composite oxide nanoparticles having a
composition expressed by the formula MEAGW(i-G)Oj described above,
the composition becomes MEAOJ and does not contain tungsten.
However, electrons are generated when an element M is added
even in a material that does not include tungsten. Absorption
in the near-infrared region occurs via the same mechanism as
in the case of MEAGW(i-G)Oj (where G Therefore, the composition can be handled in the same manner
as in the case in which tungsten is included in the
composition (when G [0192]
The infrared-shielding nanoparticles that Include
composite oxide nanoparticles of the present embodiment absorb
a considerable amount of light in the near-infrared region,
and particularly in the vicinity of the wavelength 1,000 run.
Therefore, the transmission color tone is often between a blue
color and a green color. The diameter of the infraredshielding
nanoparticles can be selected based on the intended
use. First, when the particles are to be used in applications
in which high transparency is to be retained, the particle
diameter is preferably 800 nm or less. This is due to the
fact that particles having a diameter of less than 800 nm do
not perfectly shield light by scattering the light, visibility
is retained in the visible light region, and transparency can
be simultaneously retained with good efficiency. In the
particular case that importance is placed on transparency in
the visible light region, the scattering produced by the
particles is preferably given further consideration.
[0193]
When importance is placed on reducing scattering produced
by the particles, the particle diameter of is 200 nm or less,
and more preferably 100 nm or less. The reason for this is
that if the diameter of the composite oxide nanoparticles is
small, the scattering of light in the visible light wavelength
region of 400 nm to 780 nm is reduced due to geometrical
scattering or Mie scattering. Therefore, it is possible to
avoid a situation in which the infrared-shielding nanoparticle
dispersion becomes similar to clouded glass and clear
transparency cannot be obtained. In other words, when the
particle diameter of the composite oxide nanoparticles is 200
nm or less, the geometrical scattering or Mie scattering is
reduced and a Rayleigh scattering region is formed. This is
due to the fact that the scattered light is reduced in an
inverse proportion to the particle diameter by a factor of 6
in this Rayleigh scattering region, and the scattering is
reduced as the particles are made smaller and the transparency
is enhanced. When the particle diameter is 100 nm or less,
the amount of scattered light is very low, and such a
situation is even more preferred. From the standpoint of
avoiding the scattering of light, the particle diameter is
preferably small. Also, if the particle diameter is 1 nm or
greater, the particles are easy to manufacture on a commercial
scale.
[0194]
To improve the weather resistance of the infraredshielding
nanoparticles , the surfaces of the composite oxide
nanoparticles constituting the infrared-shielding
nanoparticles of the present embodiment are preferably covered
by an oxide having one or more elements selected from Si, Ti,
Zr, and Al. However, when the nanoparticles are to be used in
electroconductive applications, resistance is increased due to
higher contact resistance between the particles when the
surface of the particles is covered by the oxide. Therefore,
the nanoparticles are preferably not used in cases in which
lower resistance is desired.
[0195]
2. Method for manufacturing infrared-shielding
nanoparticles
The composite oxide nanoparticles expressed by the
general formula MEAGW{i-G)Oj may be obtained by heat treating the
starting material in an atmosphere of an inert gas and/or
reducing gas.
The starting material of the element A and tungsten is
riot particularly limited as long as tungsten or element A is
Included. Examples that may be used include one or more
compounds selected from oxides, hydrated oxides, chlorides,
ammonium salts, carbonates, nitrates, sulfates, oxalates,
hydroxides, peroxides, and simple metals. Organic compounds
or compounds containing two or more types of metal elements
(e.g., sodium tungstate) may also be used. An advantageous
commercial manufacturing method is one in which impurities
that are difficult to remove during heat reduction are not
produced when oxides, carbonates, hydrates, or the like are
used.
[0196]
In the composite oxide nanoparticles expressed by the
general formula MEAGW(i_G)Oj, the starting material of the
element M may include the element M, and the starting material
of the element A may include the element A. No particular
limitations are imposed. However, preferred examples include
one or more compounds selected from oxides, hydrates of oxides,
chlorides, ammonium salts, carbonates, nitrates, sulfates,
oxalates, hydroxides, peroxides, and simple metals. Also,
organic complexes, or compounds containing two or more types
of metal elements (e.g., sodium tungstate) may be used. An
advantageous commercial manufacturing method is one in which
impurities are not produced during heat reduction when oxides,
carbonates, hydrates, or the like are used.
[0197]
The starting materials of the tungsten W, element A, and
element M that can form a solution (chlorides, nitrates, and
the like) are preferably formed into a solution, mixed, and
dried into a powder to obtain a starting material of composite
oxide nanoparticles, whereby sufficient mixing can be achieved.
It is apparent that even if the starting material cannot be
formed into a solution, the powder may be directly mixed to
obtain a starting material of the composite oxide
nanoparticles.
[0198]
Here, the heat treatment condition maintained after the
starting material of the element M, as well as tungsten and
the starting material of the element A, have been mixed is
preferably 250°C or greater. Infrared-shielding material film
nanoparticles obtained by heat treatment at 250°C or greater
have sufficient electrical conductivity and near-infrared
absorbency.
Ar, N2, or another inert gas may be used as the heat
treatment atmosphere. Ammonia or hydrogen gas may be used as
the reducing gas.
When hydrogen gas is used, hydrogen gas as a component of
the reducing atmosphere is preferably present in a volume
ratio of 0.1% or greater and, and more preferably in a volume
ratio of 1% or greater. Reduction can progress with good
efficiency when hydrogen gas is present in a volume ratio of
0.1% or greater.
[0199]
From the standpoint of improving the weather resistance,
the surface of the composite oxide nanoparticles obtained in
the above-described step is preferably covered by an oxide
having one or more metals selected from Si, Ti, Zr, and Al.
The covering method is not particularly limited, but it is
possible to cover the surfaces of the infrared-shielding
nanoparticles by adding an alkoxide of the above-noted metals
to the solution in which the Infrared-shielding nanoparticles
have been dispersed.
[0200]
3. Infrared-shielding nanoparticle dispersion and
infrared-shielding body
A method for using the infrared-shielding nanoparticles
of the present embodiment entails dispersing infraredshielding
nanoparticles in a suitable medium to obtain an
infrared-shielding nanoparticle dispersion, and forming a film
on the surface of a desired base material. It is possible to
pre-bake the infrared-shielding nanoparticles at a high
temperature, and knead the resulting infrared-shielding
nanoparticles into a base material or bind the particles to
the base material surface using a medium. Application can
therefore be made to resins and other base materials that have
a low heat-resistance temperature. For this reason, such a
body can be manufactured at low cost without the use of bulky
equipment when the film is formed on a base material.
Also, since the composite oxide nanoparticles that
include the infrared-shielding nanoparticles of the present
embodiment are composed of an electroconductive material,
application can be made to optical and electroconductive uses
when the material is used as a continuous film (dispersed
body).
[0201]
(a) Method for dispersing infrared-shielding
nanoparticles in a medium and forming a film on base material
surfaces
A thin film in which the infrared-shielding nanoparticles
are dispersed can be formed by dispersing the infraredshielding
nanoparticles of the present embodiment in an
appropriate solvent, adding a resin medium, applying the
resulting dispersion to the surface of a base material, and
vaporizing the solvent to cure the resin by a prescribed
method. The coating method is not particularly limited as
long as the resin containing the infrared-shielding
nanoparticles can be uniformly applied to the surface of a
base material. Examples include bar coating, gravure coating,
spray coating, and dip coating. Films in which the infraredshielding
nanoparticles are directly dispersed in a resin
medium are environmentally and commercially preferred because
the solvent does not have to be vaporized after the film has
been applied to the surface of a base material.
[0202]
Resin or glass may be used as the above-described medium.
The medium may be selected from, e.g., a UV-curable resin,
a thermosetting resin, an electron beam-curable resin, a room
temperature-curable resin, a thermoplastic resin, or another
resin in accordance with the purpose. Specific examples of
the resin include polyethylene resin, polyvinyl chloride resin,
polyvinylidene chloride resin, polyvinyl alcohol resin,
polystyrene resin, polypropylene resin, ethylene-vinyl acetate
copolymer, polyester resin, polyethylene terephthalate resin,
fluorine resin, polycarbonate resin, acrylic resin, and
polyvinyl butyral resin. A medium that uses a metal alkoxide
may also be used as the medium. Typical examples of metal
alkoxides include those of Si, Ti, Al, and Zr. Media that use
these metal alkoxides may be subjected to hydrolysis and then
heated to form an oxide film.
The shape of the base material is not limited, and the
base material may be formed in the shape of a film or board as
desired. PET, acryl, urethane, polycarbonate, polyethylene,
ethylene-vinyl acetate copolymer, vinyl chloride, fluorine
resin, or the like may be used in accordance with the Intended
purpose. Apart from resins, glass may be used.
[0203]
(b) Method for dispersing infrared-shielding
iianoparticles in a base material
The infrared-shielding nanoparticles of the present
embodiment may be dispersed in a based material. In order to
disperse the infrared-shielding nanoparticles in a base
material, the infrared-shielding material particles may be
allowed to permeate from the surface of the base material, or
the temperature of the particles may be Increased above the
melting temperature of the base material, and the particles
may then be melted and mixed with resin. The resulting resin
containing the infrared-shielding nanoparticles may be molded
into a film or a board by a prescribed method and used as an
infrared-shielding nanoparticle-molded body.
An example of a method for dispersing the infraredshielding
nanoparticles in a PET resin entails mixing PET
resin and a liquid dispersion of the infrared-shielding
nanoparticles, vaporizing the dispersion solvent, thereafter
heating the PET resin to about 300°C, which is the melting
point of PET resin, to melt and mix the PET resin, and then
cooling the material to produce a PET resin in which the
infrared-shielding nanoparticles are dispersed.
The method for dispersing the Infrared-shielding
nanoparticles is not particularly limited, and ultrasonic
irradiation, a bead mill, a sand mill, or the like can be used.
for example. Additives may be added to obtain a uniform
dispersed body, and the pH may be adjusted.
[0204]
(c) Infrared-shielding body
The infrared-shielding nanoparticles of the present
embodiment may be formed into an infrared-shielding
nanoparticle dispersion by applying the nanoparticles to a
base material as described above and kneading the
nanoparticles into the base material, or by using another
method.
An infrared-shielding body can be obtained by forming the
infrared-shielding nanoparticle dispersion into the form of a
plate, film, or thin film.
The infrared-shielding nanoparticle dispersion contains
electroconductive composite oxide nanoparticles, and when the
dispersion is applied to a base material using the same method
as that described above and kneaded into the base material,
the electrical conductivity of the infrared-shielding
nanoparticle dispersion spreads two-dimensionally or threedimensionally
via the contact of the composite oxide
nanoparticles. As a result, the infrared-shielding
nanoparticle dispersion is provided with electrical
conductivity. A visible light-transmitting, electroconductive,
infrared-shielding body can be obtained by forming the
infrared-shielding nanoparticle dispersion into the form of a
plate, film or thin film.
[0205]
4. Optical and electroconductive characteristics of the
infrared-shielding nanoparticle dispersion and infraredshielding
body.
Since the infrared-shielding nanoparticles of the present
invention have the above-described infrared-shielding ability,
the infrared-shielding nanoparticle dispersion can be formed
into a plate, film, or thin film to produce an infraredshielding
body. It is possible to obtain an infraredshielding
body that has an infrared-shielding function in
which the V value is 10% or greater when the maximum
transmittance of all light rays in the wavelength region of
400 nm to 700 nm is set to the V value, and the minimum
transmittance of all light rays in the wavelength region of
700 nm to 2,600 nm is equal to or less than the value V, and
is 65% or less.
[0206]
The Infrared-shielding function is described in further
detail below using as an example the infrared-shielding
nanoparticle (Rb0.33MoO3) dispersion film of example 24
described below.
FIG. 11 is a transmission profile of light in an
Infrared-shielding film, which is the infrared-shielding
nanoparticle (Rb0.33MoO3) dispersion of example 24. It was
determined that the value V, which is the maximum
transmittance of light in the wavelength region of 400 nm and
700 nm, is 80.25% and that visible light is adequately
transmitted, as shown in FIG. 11. It was also determined that
the minimum transmittance of all light rays in the wavelength
region of 700 nm to 2,600 nm is 22.65%, which is the V value
or less, and that light in the near-infrared region is
adequately shielded.
[0207]
The infrared-shielding nanoparticle dispersion contains
electroconductive composite oxide nanoparticles, and when the
dispersion is applied to a base material using the same method
as that described above and kneaded into the base material,
the electrical conductivity of the infrared-shielding
nanoparticle dispersion spreads two-dimensionally or threedimensionally
via the contact of the composite oxide
nanoparticles. As a result, the infrared-shielding
nanoparticle dispersion is provided with electrical
conductivity. A visible light-transmitting, electroconductive
infrared-shielding body can be obtained by forming the
infrared-shielding nanoparticle dispersion into a plate, film,
or thin film. It is possible to obtain a visible lighttransmitting,
electroconductive, infrared-shielding body in
which the maximum transmittance of all light rays in the
wavelength region of 400 nm to 700 nm is set to the V value or
greater (defined as the V value), and the surface resistance
is 1 x 1010 Q/square.
[0208]
When transparency is required, the particle diameter must
be 800 nm or less, as described above. The contact resistance
per unit of volume increases when the particle diameter is
made very small, and this situation is not preferred for
reducing resistance. Also, the shape of the particles may be
granular, tabular, or acicular (fibrous). In order to improve
electrical conductivity, tabular or acicular shapes that can
reduce the contact resistance are preferred.
[Examples]
[0209]
The present invention is described in greater detail
below using examples, but the present Invention is not limited
by the examples.
[0210]
Examples 1 to 13, and Comparative Example 1 are
principally related the above-described [1] visible light
transmitting particle-dispersed electrical conductor,
electroconductive particles, visible-light-transmitting
electroconductive article, and method for manufacturing the
same. The optical characteristics of the visible light
transmitting particle-dispersed electrical conductor were
measured using a spectrophotometer (U-400 manufactured by
Hitachi Ltd.), and visible-light transmittance (based on JIS
R3106) was calculated. The haze value was measured based on
JIS K 7105 using a measuring apparatus HR-200 manufactured by
Murakami Color Research Laboratory. The average dispersion
particle diameter was measured using a measuring apparatus
(ELS-800 (Otsuka Denki, K.K.)) that uses dynamic light
scattering. The average of three measurements was used as the
mean dispersion particle diameter. The evaluation of the
conduction characteristics was performed by measuring the
surface resistance of the fabricated films. The surface
resistance of the films was measured using Hiresta IP MCPHT260
manufactured by Mitsubishi Petrochemical Co.
The pressed powder resistance was carried out using the
van der Pauw method (see Jikken Kagaku Koza 9: Electricity and
Magnetism, Fourth edition, June 5, 1991, Ed.: The Chemical
Society of Japan, Publisher: Maruzen.) The samples were
pressed pellets shaped as discolds having a diameter of 10 mm,
and four terminal electrodes were disposed at 90° intervals on
the disk surface. A current was allowed to flow between two
adjacent terminals while applying 9.8 MPa of pressure, the
voltage at the other two terminals was measured, and the
resistance was calculated.
[0211]
(Example 1)
Tungsten hexachloride was dissolved in ethanol, and the
solution was dried at 130°C to obtain a hydrate of tungsten
oxide. This starting material was heated at 550°C for one hour
in a reducing atmosphere (volume ratio: argon/hydrogen - 95/5),
cooled to room temperature, and then heated at 800°C for one
hour in an argon atmosphere, thus producing the target
tungsten oxide powder.
As a result of determining the crystal phase via X-ray
diffraction, the resulting powder was determined to be a socalled
Magnell phase Wi8O49 (WO2.72). FIGS. 4A and 4B show the
result of viewing the shape of the powder via SEM. In this
case, FIG. 4A is an SEM image of Wi8O49 at a magnification of
10,000. and FIG. 45 is an SEM image at a magnification of
3,000.
At this time, acicular crystals were observed, as shown
in FIGS. 4A and 4B. Also, the pressed powder resistance of
the particles measured under a pressure of 9.8 MPa was 0.085
Q-cm, and good electrical conductivity was confirmed.
[0212]
Next, 20 parts by weight of the powder of the WO2.72
electroconductlve particles, 79 parts by weight of toluene,
and 1 part by weight of a dispersing agent were mixed and
irradiated with ultrasonic waves in order to disperse acicular
crystals while allowing the crystals to retain their shape. A
liquid dispersion was thus obtained. Next, 10 parts by weight
of this liquid dispersion, and 0.1 parts by weight of a UVcuring
resin as a hard coat were mixed. This solution was
applied to glass using a bar coater to form a film. This film
was dried for 30 seconds at 60°C, the solvent was allowed to
evaporate, and the film was then cured using a high pressure
mercury lamp to obtain a visible light transmitting particledispersed
electrical conductor film (hereinafter simply
abbreviated as "electrical conductor film").
[0213]
The following results were obtained when the optical
characteristics of the electrical conductor film were measured.
The visible-light transmittance was 63%,, and light in the
visible region was adequately transmitted. The haze value was
3.5%, transparency was high, the transmitted color tone was a
beautiful blue color, and the surface resistance was 7.6 x 108
Q/square.
[0214]
(Example 2)
An aqueous solution of ammonium metatungstate was dried
at 130°C to obtain a compound composed of tungsten oxide in the
form of a powder. This starting material was heated at 550°C
for one hour in a reducing atmosphere (volume ratio:
argon/hydrogen - 97/3), cooled to room temperature, and then
heated at 800°C for one hour in an argon atmosphere to prepare
tungsten oxide powder. As a result of determining the crystal
phase via X-ray diffraction, a crystal phase Wi8O49 (WO2.72) was
observed. In this manner, the same electroconductive
particles as in Example 1 were successfully fabricated even
when ammonium metatungstate was used as the tungsten compound
starting material. The pressed powder resistance of the
powder electroconductive particles measured under a pressure
of 9.8 MPa was 0.089 Q-cm, and good electrical conductivity
was confirmed.
[0215]
(Example 3)
Cesium carbonate and tungstic acid were mixed using a
mortar in a Cs/W molar ratio of 0.33. This starting material
was heated at 600°C for two hours in a reducing atmosphere
(volume ratio: argon/hydrogen - 97/3), cooled to room
temperature, and then heated at 800°C for one hour in an argon
atmosphere to prepare a powder composed of Cs0.33WO3
electroconductive particles. As a result of determining the
crystal phase via X-ray diffraction, this Cs0.33WO3 was found to
be hexagonal tungsten bronze. The resulting powder form of
the ©lectroconductive particles was viewed using an SEM. The
results are shown in FIG. 5. FIG. 5 is an SEM image of
Cs0.33WO3 at a magnification of 10,000.
At this time, crystals shaped as hexagonal pillars were
observed, as shown in FIG. 5. The pressed powder resistance
of the electroconductive particle powder measured under a
pressure of 9.8 MPa was 0.013 Q-cm, and good electrical
conductivity was confirmed.
[0216]
Next, 20 parts by weight of the powder of the Cs0.33WO3
electroconductive particles, 79 parts by weight of toluene,
and 1 part by weight of a dispersing agent were mixed and
dispersed using a media-agitating mill to prepare a liquid
dispersion in which the average dispersion particle (*6) was
100 nm. Next, 10 parts by weight of this liquid dispersion,
and 0.1 parts by weight of a UV-curing resin (solid content:
100%) as a hard coat were mixed. This solution was applied to
glass using a bar coater to form a film. This film was dried
for 30 seconds at 60°C, the solvent was allowed to evaporate,
and the film was then cured using a high pressure mercury lamp
to obtain an electrical conductor film.
[0217]
The following results were obtained when the optical
characteristics of the electrical conductor film were measured.
The visible-light transmittance was 77%, and light in the
visible region was adequately transmitted. The haze value was
0.2%, transparency was high, and the internal state could be
clearly viewed from the exterior. The transmitted color tone
was a beautiful blue color, and the surface resistance was 2.8
x 109 Q/square.
[0218]
(Example 4)
Cesium carbonate and tungstlc acid were mixed using a
mortar in a Cs/W ratio of 0.35. This starting material was
heated at 600°C for two hours in a reducing atmosphere (volume
ratio: argon/hydrogen = 97/3), cooled to room temperature, and
then heated at 800°C for one hour in an argon atmosphere to
prepare a powder composed of Cso.3sWO3 electroconductive
particles. As a result of determining the crystal phase via
X-ray diffraction, this Cso.3sWO3 was observed to have a
hexagonal crystal phase. The resulting powder was viewed
using an SEM. The results are shown in FIGS. 6A and 6B. FIG.
6A is an SEM image of Cs0.3sWO3 at a magnification of 5,000, and
FIG. 6B is an SEM image at a magnification of 10,000.
At this time, tabular crystals were observed, as shown in
FIG. 6. In this manner, it was determined that tabular
crystals are generated by Increasing the Cs addition amount
above 0.33. The pressed powder resistance of the powder
measured under a pressure of 9.8 MPa was 0.0096 Q-cm, and good
electrical conductivity was confirmed.
[0219]
(Example 5)
Cesium carbonate and tungstic acid were mixed using a
mortar in a Cs/W molar ratio of 0.33. This starting material
was heated at 600°C for two hours in a reducing atmosphere
(volume ratio: argon/hydrogen - 97/3) to prepare a powder
composed of Cso.3aWO3 electroconductive particles. As a result
of determining the crystal phase via X-ray diffraction, this
Cs0.33WO3 was observed to have a hexagonal crystal phase. The
pressed powder resistance of the particles measured under a
pressure of 9.8 MPa was 0.013 Q-cm, and good electrical
conductivity was confirmed.
[0220]
Next, 20 parts by weight of the powder of the Cs0.33WO3
electroconductive particles, 79 parts by weight of toluene,
and 1 part by weight of a dispersing agent were mixed and
dispersed using a media-agitating mill to prepare a liquid
dispersion in which the average dispersion particle (*6) was
120 nm. Next, 10 parts by weight of this liquid dispersion,
and 0.1 parts by weight of a UV-curing resin (solid content:
100%) as a hard coat were mixed. This solution was applied to
glass using a bar coater to form a film. This film was dried
for 30 seconds at 60°C, the solvent was allowed to evaporate,
and the film was then cured using a high pressure mercury lamp
to obtain an electrical conductor film.
[0221]
The following results were obtained when the optical
characteristics of the electrical conductor film were measured.
The visible-light transmittance was 63%, and light in the
visible region was adequately transmitted. The haze value was
0.8%, transparency was high, and the Internal state could be
clearly viewed from the exterior. The transmitted color tone
was a beautiful blue color, and the surface resistance was 3.6
x 108 Q/square.
[0222]
(Example 6)
Rubidium carbonate and tungstic acid were mixed using a
mortar in an Rb/W ratio of 0.33. This starting material was
heated at 600°C for two hours in a reducing atmosphere (volume
ratio: argon/hydrogen = 97/3), cooled to room temperature, and
then heated at 800°C for one hour in an argon atmosphere to
prepare a powder composed of Rb0.33W03 electroconductive
particles. As a result of determining the crystal phase via
X-ray diffraction, this Rbo.aaWOa was observed to have a
hexagonal crystal phase. The resulting powder of the
electroconductive particles was viewed by SEM, and
microcrystals shaped as hexagonal pillars were observed. The
pressed powder resistance of the particles measured under a
pressure of 9.8 MPa was 0.0086 Q-cm, and good electrical
conductivity was confirmed.
[0223]
Next, 20 parts by weight of the powder of the Rb0.33WO3
electroconductive particles, 79 parts by weight of toluene,
and 1 part by weight of a dispersing agent were mixed and
dispersed using a media-agitating mill to prepare a liquid
dispersion in which the average dispersion particle diameter
was 80 nm. Next, 10 parts by weight of this liquid dispersion,
and 0.1 parts by weight of a UV-curing resin (solid content:
100%) as a hard coat were mixed. This solution was applied to
glass using a bar coater to form a film. This film was dried
for 30 seconds at 60°C, the solvent was allowed to evaporate,
and the film was then cured using a high pressure mercury lamp
to obtain an electrical conductor film.
[0224]
The following results were obtained when the optical
characteristics of the electrical conductor film were measured,
The visible-light transmittance was 76%, and light in the
visible region was adequately transmitted. The haze value was
0.2%, transparency was high, and the internal state could be
clearly viewed from the exterior. The transmitted color tone
was a beautiful blue color, and the surface resistance was 4.2
x 10* Q/sguare.
[0025]
(Example 7)
Rubidium carbonate and tungstic acid were mixed using a
mortar in an Rb/W ratio of 0.33. This starting material was
heated at 600°C for two hours in a reducing atmosphere (volume
ratio: argon/hydrogen - 97/3), cooled to room temperature, and
then heated at 800°C for one hour in an argon atmosphere to
prepare a powder composed of Rb0.33WO3 electroconductive
particles. As a result of determining the crystal phase via
X-ray diffraction, this Rb0.33WO3 was observed to have a
hexagonal crystal phase. The resulting powder was viewed
using an SEM. The results are shown in FIGS. 7A and 7B. FIG.
7A is an SEM image of Rbo.aaWCb at a magnification of 200, and
FIG. 7B is an SEM image at a magnification of 1,000.
At this time, fibrous crystals shaped as hexagonal
pillars were observed, as shown in FIGS. 7A and 7B.
The pressed powder resistance of the powder was measured
and found to be 0.0046 Q-cm, and good electrical conductivity
was confirmed.
[0226]
Next, 20 parts by weight of the powder of the Rb0.33wO3. 79
parts by weight of toluene, and 1 part by weight of a
dispersing agent were mixed and dispersed using ultrasonic
Irradiation to prepare a fibrous-particle liquid dispersion.
Next, 10 parts by weight of this liquid dispersion, and 0.1
parts by weight of a UV-curing resin (solid content: 100%) as
a hard coat were mixed. This solution was applied to glass
using a bar coater to form a film. This film was dried for 30
seconds at 60°C, the solvent was allowed to evaporate, and the
film was then cured using a high pressure mercury lamp to
obtain an electrical conductor film.
When the optical characteristics of the electrical
conductor film were measured, the visible-light transmittance
was found to be 56%, and light in the visible region was
adequately transmitted. The haze value was 8.2%, transparency
was high, and the Internal state could be clearly viewed from
the exterior. The transmitted color tone was a beautiful blue
color, and the surface resistance was 3.1 x 106 Q/square.
[0227]
(Example 8)
Potassium carbonate and tungstic acid were mixed using a
mortar in a K/W ratio of 0.33. This starting material was
heated at 600°C for two hours in a reducing atmosphere (volume
ratio: argon/hydrogen - 97/3), cooled to room temperature, and
then heated at 800°C for one hour in an argon atmosphere to
prepare a powder composed of K0.33WO3 electroconductive
particles. As a result of determining the crystal phase via
X-ray diffraction, this K0.33WO3 was observed to have a
hexagonal crystal phase. The resulting powder form of the
electroconductive particles was viewed using an SEM, and
micr©crystals shaped as hexagonal pillars were observed. The
pressed powder resistance of the powder electroconductive
particles measured under a pressure of 9.8 MPa was 0.049 Q-cm,
and good electrical conductivity was confirmed.
[0228]
Next, 20 parts by weight of the powder of the K0.33WO3
electroconductive particles, 79 parts by weight of toluene,
and 1 part by weight of a dispersing agent were mixed and
dispersed using a media-agitating mill to prepare a liquid
dispersion in which the average dispersion particle (*6) was
80 nm. Next, 10 parts by weight of this liquid dispersion.
and 0.1 parts by weight of a UV-curing resin (solid content:
100%) as a hard coat were mixed. This solution was applied to
glass using a bar coater to form a film. This film was dried
for 30 seconds at 60° C, the solvent was allowed to evaporate,
and the film was then cured using a high pressure mercury lamp
to obtain an electrical conductor film.
[0229]
When the optical characteristics of the electrical
conductor film were measured, the visible-light transmittance
was found to be 62%, and light in the visible region was
adequately transmitted. The haze value was 0.9%, transparency
was high, and the internal state could be clearly viewed from
the exterior. The transmitted color tone was a beautiful blue
color, and the surface resistance was 7.3 x 109 Q/square.
[0230]
(Example 9)
Barium carbonate and tungstic acid were mixed using a
mortar in a Ba/W ratio of 0.33. This starting material was
heated at 550°C for two hours in a reducing atmosphere (volume
ratio: argon/hydrogen - 97/3), cooled to room temperature, and
then heated at 700°C for one hour in an argon atmosphere to
prepare a powder composed of Ba0.33WO3 electroconductive
particles. As a result of determining the crystal phase via
X-ray diffraction, this Ba0.33WO3 was observed to have a
hexagonal crystal phase. The resulting powder form of the
electroconductive particles was viewed using an SEM, and
microcrystals shaped as hexagonal pillars were observed. The
pressed powder resistance of the powder electroconductive
particles measured under a pressure of 9.8 MPa was 0.068 Q-cm,
and good electrical conductivity was confirmed.
[0231]
Next, 20 parts by weight of the powder of the Bao.aaWOa
electroconductive particles, 79 parts by weight of toluene,
and 1 part by weight of a dispersing agent were mixed and
dispersed using a media-agitating mill to prepare a liquid
dispersion in which the average dispersion particle (*6) was
95 nm. Next, 10 parts by weight of this liquid dispersion,
and 0.1 parts by weight of a UV-curing resin (solid content:
100%) as a hard coat were mixed. This solution was applied to
glass using a bar coater to form a film. This film was dried
for 30 seconds at 60° C, the solvent was allowed to evaporate,
and the film was then cured using a high pressure mercury lamp
to obtain an electrical conductor film.
[0232]
The following results were obtained when the optical
characteristics of the electrical conductor film were measured.
The visible-light transmittance was 55%, and light in the
visible region was adequately transmitted. The haze value was
1.3%, transparency was high, and the internal state could be
clearly viewed from the exterior. The transmitted color tone
was a beautiful blue color, and the surface resistance was 3.6
x 1010 Q/square.
[0233]
(Example 10)
Thallium chloride was dissolved in an aqueous solution of
ammonium metatungstate and mixed to achieve a Tl/W ratio of
0.33. This starting material was heated at 600°C for two hours
in a reducing atmosphere (volume ratio: argon/hydrogen = 97/3),
cooled to room temperature, and then heated at 800°C for one
hour in an argon atmosphere to prepare a powder composed of
Tlo.33WO3 electroconductive particles.
As a result of determining the crystal phase via X-ray
diffraction, this T10.33WO3 was observed to have a hexagonal
crystal phase. The resulting powder form of the
electroconductive particles was viewed using an SEM, and
microcrystals shaped as hexagonal pillars were observed. The
pressed powder resistance of the powder electroconductive
particles measured under a pressure of 9.8 MPa was 0.096 Q-cm,
and good electrical conductivity was confirmed.
[0234]
Next, 20 parts by weight of the powder of the T10.33WO3
electroconductive particles, 79 parts by weight of toluene,
and 1 part by weight of a dispersing agent were mixed and
dispersed using a media-agitating mill to prepare a liquid
dispersion in which the average dispersion particle (*6) was
85 nra. Next, 10 parts by weight of this liquid dispersion,
and 0.1 parts by weight of a UV-curing resin (solid content:
100%) as a hard coat were mixed. This solution was applied to
glass using a bar coater to form a film. This film was dried
for 30 seconds at 60°C, the solvent was allowed to evaporate,
and the film was then cured using a high pressure mercury lamp
to obtain an electrical conductor film.
[0235]
The following results were obtained when the optical
characteristics of the electrical conductor film were measured.
The visible-light transmittance was 72%, and light in the
visible region was adequately transmitted. The haze value was
1.1%, transparency was high, and the Internal state could be
clearly viewed from the exterior. The transmitted color tone
was a beautiful blue color, and the surface resistance was 6.2
x 1011 Q/square.
[0236]
(Example 11)
Indium chloride was dissolved in an aqueous solution of
ammonium metatungstate and mixed to achieve an In/W ratio of
0.33. This starting material was heated at 500°C for one hour
in a reducing atmosphere (volume ratio: argon/hydrogen - 97/3),
cooled to room temperature, and then heated at 700°C for one
hour in an argon atmosphere to prepare a powder composed of
In0.33WO3 electroconductive particles.
As a result of determining the crystal phase via X-ray
diffraction, this In0.33WO3 was observed to have a hexagonal
crystal phase. The resulting powder form of the
electroconductive particles was viewed using an SEM, and
microcrystals shaped as hexagonal pillars were observed. The
pressed powder resistance of the powder electroconductive
particles measured under a pressure of 9.8 MPa was 0.032 Q-cm,
and good electrical conductivity was confirmed.
[0237]
Next, 20 parts by weight of the powder of the In0.33WO3
electroconductive particles, 79 parts by weight of toluene,
and 1 part by weight of a dispersing agent were mixed and
dispersed using a media-agitating mill to prepare a liquid
dispersion in which the average dispersion particle (*6) was
110 nm. Next, 10 parts by weight of this liquid dispersion,
and 0.1 parts by weight of a UV-curing resin (solid content:
100%) as a hard coat were mixed. This solution was applied to
glass using a bar coater to form a film. This film was dried
for 30 seconds at 60°C, the solvent was allowed to evaporate,
and the film was then cured using a high pressure mercury lamp
to obtain an electrical conductor film.
[0238]
The following results were obtained when the optical
characteristics of the electrical conductor film were measured.
The visible-light transmittance was 75%, and light in the
visible region was adequately transmitted. The haze value was
1.3%, transparency was high, and the internal state could be
clearly viewed from the exterior. The transmitted color tone
was a beautiful blue color, and the surface resistance was 3.5
x 109 Q/square.
[0239]
(Example 12)
Potassium carbonate and tungstic acid were mixed using a
mortar in a K/W ratio of 0.55. This starting material was
heated at 600°C for two hours in a reducing atmosphere (volume
ratio: argon/hydrogen = 97/3), cooled to room temperature, and
then heated at 800°C for one hour in an argon atmosphere to
prepare a powder composed of K0.55WO3 electroconductive
particles. As a result of determining the crystal phase via
X-ray diffraction, this Ko.ssWO3 was observed to have a
tetragonal crystal phase. The resulting powder form of the
electroconductive particles was viewed using an SEM, and
rectangular parallelepiped microcrystals were observed. The
pressed powder resistance of the powder electroconductive
particles measured under a pressure of 9.8 MPa was 0.12 Q-cm,
and good electrical conductivity was confirmed.
[0240]
Next, 20 parts by weight of the powder of the Ko.ssWO3
electroconductive particles, 79 parts by weight of toluene,
and 1 part by weight of a dispersing agent were mixed and
dispersed using a media-agitating mill to prepare a liquid
123
dispersion in which the average dispersion particle (*6) was
95 run. Next, 10 parts by weight of this liquid dispersion,
and 0.1 parts by weight of a UV-curing resin (solid content:
100%) as a hard coat were mixed. This solution was applied to
glass using a bar coater to form a film. This film was dried
for 30 seconds at 60°C, the solvent was allowed to evaporate,
and the film was then cured using a high pressure mercury lamp
to obtain an electrical conductor film.
[0241]
When the optical characteristics of the electrical
conductor film were measured, the visible-light transmittance
was found to be 62%, and light in the visible region was
adequately transmitted. The haze value was 1.2%, transparency
was high, and the internal state could be clearly viewed from
the exterior. The transmitted color tone was a beautiful blue
color, and the surface resistance was 5.7 x 1011 Q/square.
[0242]
(Example 13)
Sodium carbonate and tungstic acid were mixed using a
mortar in a Na/W ratio of 0.50. This starting material was
heated at 600°C for two hours in a reducing atmosphere (volume
ratio: argon/hydrogen = 97/3), cooled to room temperature, and
then heated at 800°C for one hour in an argon atmosphere to
prepare a powder composed of Na0.5oWO3 electroconductive
particles. As a result of determining the crystal phase via
X-ray diffraction, this Na0.5oWO3 was observed to have a
tetragonal crystal phase. The pressed powder resistance of
the powder electroconductive particles measured under a
pressure of 9.8 MPa was 0.18 Q-cm, and good electrical
conductivity was confirmed.
[0243]
Next, 20 parts by weight of the powder of the Na0.5owO3
electroconductive particles , 79 parts by weight of toluene,
and 1 part by weight of a dispersing agent were mixed and
dispersed using a media-agitating mill to prepare a liquid
dispersion in which the average dispersion particle (*6) was
50 nm. Next, 10 parts by weight of this liquid dispersion,
and 0.1 parts by weight of a UV-curing resin (solid content:
100%) as a hard coat were mixed. This solution was applied to
glass using a bar coater to form a film. This film was dried
for 30 seconds at 60"C, the solvent was allowed to evaporate,
and the film was then cured using a high pressure mercury lamp
to obtain an electrical conductor film.
[0244]
When the optical characteristics of the electrical
conductor film were measured, the visible-light transmittance
was found to be 52%, and light in the visible region was
adequately transmitted. The haze value was 0.6%, transparency
was high, and the internal state could be clearly viewed from
the exterior. The transmitted color tone was a beautiful blue
color, and the surface resistance was 4.8 x 1011 Q/square.
[0245]
(Comparative Example 1)
Commercially available tungsten trioxide powder (20 parts
by weight), 79.5 parts by weight of toluene, and 1.0 part by
weight of a dispersing agent were mixed and dispersed using a
media-agitating mill to prepare a liquid dispersion in which
the average dispersion particle (*6) was 80 nm. Next, 20
parts by weight of this liquid dispersion, and 0.1 parts by
weight of a UV-curing resin (solid content: 100%) as a hard
coat were mixed. This solution was applied to glass using a
bar coater to form a film. This film was dried for 30 seconds
at 60°C, the solvent was allowed to evaporate, and the film
was then cured using a high pressure mercury lamp to obtain an
electrical conductor film.
[0246]
When the optical characteristics of the film were
measured, the visible-light transmittance was found to be 89%
and most of the light in the visible region was transmitted,
but the surface resistance could not be measured, and the
dispersion was difficult to use as an electrical conductor
film.
Embodiments of the present invention were described above,
but the present invention is not limited by these embodiments.
A list of the measurement results of examples 1 to 13 and
Comparative Example 1 Is shown In TABLE 1.
(Table Removed)
[0248]
Examples 14 to 23, and Comparative Example 2 are
principally related the above-described [2] transparent
electroconductive film and method for manufacturing the same,
transparent electroconductive article, and infrared-shielding
article. Optical measurements were carried out based on JIS
3106 (light source: A light), and the visible-light
transmittance was calculated. The conduction characteristics
were measured using a surface resistance measuring instrument
(Loresta MP MCP-T350) manufactured by Mitsubishi Chemical.
[0249]
(Example 14)
9.28 g of an aqueous solution of ammonium metatungstate
(0.02 mol/9.28 g) and an aqueous solution (an aqueous solution
obtained by dissolving 0.080 g of rubidium chloride in 80 g of
water) of rubidium chloride (RbCl) were mixed in a Rb/W atomic
ratio of 0.33. A surfactant (FZ2105 (Adeka)) was added to the
solution in a concentration of 0.002% relative to the entire
solution to obtain a film-forming solution. The film-forming
solution was applied by dipping to one side of a transparent
quartz plate (thickness: 2 mm). The plate was heat treated
for 10 minutes at 550°C in an atmosphere of 5% hydrogen (the
balance being nitrogen) to obtain a transparent
electroconductive film on a substrate. The film thickness was
about 110 nm.
[0250]
The film was measured by XRD and found to be hexagonal Rb
tungsten bronze. The transmittance and reflectivity of the
resulting film were measured. FIG. 8 shows transmission and
reflection profiles of the film. FIG. 8 is a graph in which
the wavelength of the transmitted light is plotted along the
horizontal axis, and the transmittance and reflectivity of the
light is plotted along the vertical axis. The measurement
results of the transmittance are plotted as a solid line, and
the measurement results of the reflectivity are plotted as a
broken line.
Based on the measurement results, the transmittance of
visible light of this film was 77.38%, transparency was high,
infrared light having a wavelength of 800 nm and above was
reflected or absorbed, and the film was found to be effective
as an infrared-shielding material. The solar light
transmittance of the film was 57%. Hence, 43% of the passing
solar light was shielded. The surface resistance of the film
was 6.9 x 103 Q/square, and the electrical conductivity was
determined to be high.
[0251]
(Example 15)
The baked film obtained in example 14 was dip coated
again on one side using the same method and the film-forming
solution of example 14. The plate was heat treated for 10
minutes at 550°C in an atmosphere of 5% hydrogen (the balance
130
being nitrogen) to obtain a transparent electroconductive film
on a substrate. The film thickness was about 200 run.
[0252]
The transmittance and reflectivity of the resulting film
were measured. FIG. 9 shows transmission and reflection
profiles of the film. FIG. 9 is also a graph in which the
wavelength of the transmitted light is plotted along the
horizontal axis, and the transmittance and reflectivity of the
light is plotted along the vertical axis in the same manner as
FIG. 8. The measurement results of the transmittance are
plotted as a solid line, and the measurement results of the
reflectivity are plotted as a broken line.
Based on the measurement results, the transmittance of
visible light of this film was 58.86%, transparency was high,
infrared light having a wavelength of 800 nm and above was
reflected or absorbed, and the film was found to be effective
as an infrared-shielding material. The solar light
transmittance of the film was 26%. Hence, 74% of the passing
solar light was shielded. The surface resistance of the film
was 2.6 x 102 Q/sguare, and the electrical conductivity was
determined to be higher than that of example 14.
[0253]
(Example 16)
9.28 g of an aqueous solution of ammonium metatungstate
(0.02 mo 1/9,28 g) and an aqueous solution (an aqueous solution
131
obtained by dissolving 1.11 g of cesium chloride in 80 g of
water) of cesium chloride (CsCl) were mixed in a Cs/W atomic
ratio of 0.33. A surfactant (FZ2105 (Adeka)) was added to the
solution in a concentration of 0.002% relative to the entire
solution to obtain a film-forming solution. The film-forming
solution was applied by dipping to one side of a transparent
quartz plate (thickness: 2 mm). The plate was heat treated
for 10 minutes at 550°C in an atmosphere of 5% hydrogen (the
balance being nitrogen) to obtain a transparent
electroconductive film on a substrate. The film thickness was
about 120 run.
[0254]
The transmlttance of visible light of the resulting film
was 78.16%, and the surface resistance of the film was 1.2 x
104 Q/square. The transparency and electrical conductivity of
the film was high. The solar light transmittance of the film
was 61%. Hence, 39% of the passing solar light was shielded.
[0255]
(Example 17)
9.28 g of an aqueous solution of ammonium metatungstate
(0.02 mol/9.28 g) and 80 g of water were mixed. A surfactant
(FZ2105 (Adeka)) was added to the solution in a concentration
of 0.002% relative to the entire solution to obtain a filmforming
solution. The film-forming solution was applied by
dipping to one side of a transparent quartz plate (thickness:
2 mm). The plate was heat treated for 10 minutes at 550° C in
an atmosphere of 5% hydrogen (the balance being nitrogen), and
thereafter heat treated for 10 minutes at 8008 C in a nitrogen
atmosphere to obtain a transparent electroconductive film on a
substrate. The film thickness was about 100 run.
[0256]
The film was measured by XRD and found to be Wi8O49. The
transmittance of visible light of the resulting film was
52.16%, and the surface resistance of the film was 7.3 x 105
Q/square. The film had high transparency and electrical
conductivity. The solar light transmittance of the film was
37%. Hence, 63% of the passing solar light was shielded.
[0257]
(Example 18)
Tungsten hexachloride was dissolved in ethanol, and the
tungsten concentration in the solution in this case was 0.02
mol/90 g. The solution was applied by dipping to one side of
a transparent quartz plate (thickness: 2 mm). The plate was
heat treated for 10 minutes at 550°C in an atmosphere of 5%
hydrogen (the balance being nitrogen), and thereafter heat
treated for 10 minutes at 800° C in a nitrogen atmosphere to
obtain a transparent electroconductive film on a substrate.
The film thickness was about 80 run.
[0258]
The film was measured by XRD and found to be Wi8049. The
transmittance of visible light of the resulting film was
67.16%, and the surface resistance of the film was 2.1 x 106
Q/square. The film had high transparency and electrical
conductivity.
[0259]
(Example 19)
9.28 g of an aqueous solution of ammonium metatungstate
(0.02 mo 1/9.28 g) and an aqueous solution of indium chloride
were mixed in an In/W atomic ratio of 0.33. A surfactant
(FZ2105 (Adeka)) was added to the solution in a concentration
of 0.002% relative to the entire solution to obtain a filmforming
solution. The film-forming solution was applied by
dipping to one side of a transparent quartz plate (thickness:
2 mm). The plate was heat treated for 10 minutes at 500° C in
an atmosphere of 5% hydrogen (the balance being nitrogen) to
obtain a transparent electroconductive film on a substrate.
The film thickness was about 100 nm.
[0260]
The film was measured by XRD and found to be hexagonal In
tungsten bronze. The optical characteristics of the resulting
film were measured. The transmittance of visible light of
this film was 75.22%, transparency was high, infrared light
having a wavelength of 800 nm and above was reflected or
absorbed, and the film was found to be effective as an
infrared-shielding material. The solar light transmittance of
the film was 69%. Hence, 31% of the passing solar light was
shielded.
[0261]
The surface resistance of the film was 2.3 x 104 Q/square.
and the electrical conductivity was determined to be high.
[0262]
(Example 20)
9.28 g of an aqueous solution of ammonium metatungstate
(0.02 mo 1/9.28 g) and an aqueous solution of stannic chloride
were mixed in an Sn/W atomic ratio of 0.33. A surfactant
(FZ2105 (Adeka)) was added to the solution in a concentration
of 0.002% relative to the entire solution to obtain a filmforming
solution. The film-forming solution was applied by
dipping to one side of a transparent quartz plate (thickness:
2 mm). The plate was heat treated for 10 minutes at 500* C in
an atmosphere of 5% hydrogen (the balance being nitrogen) to
obtain a transparent electroconductlve film on a substrate.
The film thickness was about 100 nm.
[0263]
The film was measured by XRD and found to be hexagonal Sn
tungsten bronze. The optical characteristics of the resulting
film were measured. The transmittance of visible light of
this film was 72.52%, transparency was high. Infrared light
having a wavelength of 800 nm and above was reflected or
absorbed, and the film was found to be effective as an
infrared-shielding material. The solar light transmittance of
the film was 67%. Hence, 33% of the passing solar light was
shielded.
[0264]
The surface resistance of the film was 6.7 x 104 Q/square,
and the electrical conductivity was determined to be high.
[0265]
(Example 21)
9.28 g of an aqueous solution of ammonium metatungstate
(0.02 mol/9.28 g), an aqueous solution of rubidium chloride,
and an aqueous solution of tantalum chloride were mixed in a
W:Ta:Rb atomic ratio of 0.9:0.1:0.33. A surfactant (FZ2105
(Adeka)) was added to the solution in a concentration of
0.002% relative to the entire solution to obtain a filmforming
solution. The film-forming solution was applied by
dipping to one side of a transparent quartz plate (thickness:
2 mm). The plate was heat treated for 10 minutes at 550°C in
an atmosphere of 5% hydrogen (the balance being nitrogen) to
obtain a transparent electroconductlve film on a substrate.
The film thickness was about 100 nm.
[0266]
The film was measured by XRD and found to be primarily
hexagonal tungsten bronze. The optical characteristics of the
resulting film were measured. The transmittance of visible
light of this film was 75.36%, transparency was high, infrared
light having a wavelength of 800 nm and above was reflected or
absorbed, and the film was found to be effective as an
infrared-shielding material. The solar light transmittance of
the film was 58%. Hence, 42% of the passing solar light was
shielded.
[0267]
The surface resistance of the film was 9.1 x 104 Q/square,
and the electrical conductivity was determined to be high.
[0268]
(Example 22)
9.28 g of an aqueous solution of ammonium metatungstate
(0.02 mo 1/9.28 g), an aqueous solution of rubidium chloride,
and an aqueous solution of niobium chloride were mixed in a
W:Nb:Rb atomic ratio of 0.9:0.1:0.33. A surfactant (FZ2105
(Adeka)) was added to the solution in a concentration of
0.002% relative to the entire solution to obtain a filmforming
solution. The film-forming solution was applied by
dipping to one side of a transparent quartz plate (thickness:
2 mm). The plate was heat treated for 10 minutes at 550° C in
an atmosphere of 5% hydrogen (the balance being nitrogen) to
obtain a transparent electroconductive film on a substrate.
The film thickness was about 110 nm.
[0269]
The film was measured by XRD and found to be primarily
hexagonal tungsten bronze. The optical characteristics of the
resulting film were measured. The transmittance of visible
light of this film was 71.25%, transparency was high, infrared
light having a wavelength of 800 nm and above was reflected or
absorbed, and the film was found to be effective as an
infrared-shielding material. The solar light transmittance of
the film was 52%. Hence, 48% of the passing solar light was
shielded.
[0270]
The surface resistance of the film was 1.3 x 10* Q/square,
and the electrical conductivity was determined to be high.
[0271]
(Example 23)
An aqueous solution of molybdenum chloride and rubidium
chloride was mixed in aho:Rb atomic ratio of 1:0.33. A
surfactant (FZ2105 (Adeka)) was added to the solution in a
concentration of 0.002% relative to the entire solution to
obtain a film-forming solution. The film-forming solution was
applied by dipping to one side of a transparent quartz plate
(thickness: 2 mm). The plate was heat treated for 10 minutes
at 500°C in an atmosphere of 5% hydrogen (the balance being
nitrogen) to obtain a transparent electroconductive film on a
substrate. The film thickness was about 150 nm.
[0272]
The film was measured by XRD and found to be molybdenum
bronze. The optical characteristics of the resulting film
were measured. The transmittance of visible light of this
film was 55.21%, transparency was high, infrared light having
a wavelength of 700 nm and above was reflected or absorbed,
and the film was found to be effective as an infraredshielding
material. The solar light transmittance of the film
was 40%. Hence, 60% of the passing solar light was shielded.
[0273]
The surface resistance of the film was 1.5 x 10s Q/square,
and the electrical conductivity was determined to be high.
[0274]
(Comparative Example 2)
9.28 g of an aqueous solution of ammonium metatungstate
(0.02 mo 1/9.28 g) was mixed with 80 g of water. A surfactant
(FZ2105 (Adeka)) was added to the solution in a concentration
of 0.002% relative to the entire solution to obtain a filmforming
solution. The film-forming solution was applied by
dipping to one side of a transparent quartz plate (thickness:
2 mm). The plate was heat treated for 10 minutes at 550" C in
the atmosphere and thereafter heat treated for 10 minutes at
800°C in the atmosphere to obtain a transparent
electroconductive film on a substrate. The film thickness was
about 100 nm.
[0275]
The film was measured by XRD and found to be WO3. The
transmittance of visible light of this film was 87.52%, the
surface resistance of the film was so high as to be
unmeasurable, and the film was found to be devoid of
electrical conductivity.
[0276]
Examples 24 to 35 and Comparative Examples 3 to 5 are
principally related the above-described [3] infrared-shielding
nanoparticle dispersion, infrared-shielding body, method for
manufacturing infrared-shielding nanoparticles, and infraredshielding
nanoparticles. Optical measurements were carried
out based on JISA 5759 (1998) (light source: A light) for
window glass films used in construction, and the visible-light
transmittance and solar light transmittance were calculated.
However, the measurement samples were not applied to glass and
the film samples themselves were used.
The haze value was measured based on JISK 7105.
The average dispersion particle diameter was measured
using a measuring apparatus (ELS-800 (Otsuka Denki, K.K.))
that uses dynamic light scattering, and the average value was
used.
The conduction characteristics were evaluated by
measuring the surface resistance of the fabricated films using
Hiresta IP MCP-HT260 manufactured by Mitsubishi Petrochemical
Co.
The optical characteristics of the base material PET film
were as follows: The HPE-50 (Teijin) used in the examples had
a visible-light transmittance of 88%, a solar light
transmittance of 88%, and a haze value of 0.9 to 0.8%.
[0277]
(Example 24)
Starting materials Rb2CO3 and MoO3-H2O were mixed using a
mortar to obtain the desired composition Rbo.33MoO3. The
composition was reduced for one hour at 450°C in an atmosphere
(flow) of hydrogen and nitrogen in a volume ratio of 3:7, and
thereafter heat treated for one hour at 800°C in an N2
atmosphere to obtain an Rb0.33MoO3 powder.
Next, 20 parts by weight of this powder, 75 parts by
weight of toluene, and 5 parts by weight of a dispersing agent
were mixed and dispersed to prepare a liquid dispersion in
which the average dispersion particle diameter was 80 run.
Next, 10 parts by weight of this liquid dispersion, and 100
parts by weight of a UV-curing resin (solid content 100%) as a
hard coat were mixed to obtain a liquid infrared-shielding
nanoparticle dispersion. This liquid Infrared-shielding
nanoparticle dispersion was applied to a PET resin film (HPE-
50) using a bar coater to form a film. This film was dried
for 30 seconds at 60°C, the solvent was allowed to evaporate,
and the film was then cured using a high pressure mercury lamp
to obtain an infrared-shielding film.
[0278]
The optical characteristics of the infrared-shielding
film are shown in TABLE 2. The transmittance peak in TABLE 2
shows the maximum transmittance of all light rays in the
wavelength region of 400 nm to 700 nm, and the transmittance
bottom is the minimum transmittance of all light rays in the
wavelength region of 700 nm to 2,600 nm.
The resulting infrared-shielding film had very high
transparency, and the internal state could be clearly viewed
from the exterior. The transmitted color tone was a beautiful
blue color. It is apparent from FIG. 11, which is a
transmission profile of light in the infrared-shielding film,
that the value V, which is the maximum transmittance of light
rays in the wavelength region of 400 nm to 700 nm as described
above, was 80.25%, and that the visible light was adequately
transmitted. The minimum transmittance of all light rays in
the wavelength region of 700 nm to 1,200 nm was 22.65% below
the V value. The average value (solar light transmittance)
was 57.0%, and the near-infrared-shielding performance was
high.
However, the above-described visible-light transmittance
and solar light transmittance vary depending on the amount of
infrared-shielding material dispersed per unit of surface area.
Therefore, the visible-light transmittance and solar light
transmittance both vary in relation to the dispersed amount of
Infrared-shielding material. The same applies in the
following examples and comparative examples.
[0279]
(Example 25)
Starting materials Rb2CO3, MoO3'H2O, and W03-H20 were mixed
using a mortar to obtain the desired composition Rb0.33Moo.3Wo.703.
The composition was reduced for one hour at 450°C in an
atmosphere (flow) of hydrogen and nitrogen in a volume ratio
of 3:7, and thereafter heat treated for one hour at 800°C in an
N2 atmosphere to obtain an Rb0.33Moo.3W0.7O3 powder. The powder
was dispersed using the same method as that used in Example 24
to form a film and obtain an infrared-shielding film.
The optical characteristics of the infrared-shielding
film are shown in TABLE 2.
The resulting infrared-shielding film had very high
transparency, and the internal state could be clearly viewed
from the exterior. The transmitted color tone was a beautiful
blue color.
[0280]
(Example 26)
Starting materials Rb2CO3, MoO3-H2O, and WO3-H2O were mixed
using a mortar to obtain the desired composition Rb0.33Mo0.5W0.5O3.
The composition was reduced for one hour at 450°C in an
atmosphere (flow) of hydrogen and nitrogen in a volume ratio
of 3:7, and thereafter heat treated for one hour at 800°C in an
N2 atmosphere to obtain an Rbo.aaMoo.sWo.sCb powder. The powder
was dispersed using the same method as that used in example 24
to form a film and obtain an infrared-shielding film.
The optical characteristics of the infrared-shielding
film are shown in TABLE 2.
The resulting infrared-shielding film had very high
transparency, and the internal state could be clearly viewed
from the exterior. The transmitted color tone was a beautiful
blue color.
[0281]
(Example 27)
Starting materials Na2CO3 and MoO3-H2O were mixed using a
mortar to obtain the desired composition Na0.33MoO3. The
composition was reduced for one hour at 550°C in an atmosphere
(flow) of hydrogen and nitrogen in a volume ratio of 3:7 to
obtain an Nao.aaMoOa powder. The powder was dispersed using the
same method as that used in Example 24 to form a film and
obtain an infrared-shielding film.
The optical characteristics of the infrared-shielding
film are shown in TABLE 2.
The resulting infrared-shielding film had very high
transparency, and the internal state could be clearly viewed
from the exterior. The transmitted color tone was a beautiful
blue color.
[0282]
(Example 28)
Starting materials Rb2CO3 and MoO3-H2O were mixed using a
mortar to obtain the desired composition Rb0.44MoO3. The
composition was reduced for one hour at 550°C in an atmosphere
(flow) of hydrogen and nitrogen in a volume ratio of 3:7, and
thereafter heat treated for one hour at 800°C in an N2
atmosphere to obtain an Rbo^MoCb powder. The powder was
dispersed using the same method as that used in Example 24 to
form a film and obtain an infrared-shielding film.
The optical characteristics of the infrared-shielding
film are shown in TABLE 2.
The resulting infrared-shielding film had very high
transparency, and the internal state could be clearly viewed
from the exterior. The transmitted color tone was a beautiful
blue color.
[0283]
(Example 29)
Starting materials K2CO3 and MoO3-H2O were mixed using a
mortar to obtain the desired composition K0.33MoO3. The
composition was reduced for one hour at 550°C in an atmosphere
(flow) of hydrogen and nitrogen in a volume ratio of 3:7, and
thereafter heat treated for one hour at 800°C in an N2
atmosphere to obtain a K0.33Mo03 powder. The powder was
dispersed using the same method as that used in Example 24 to
form a film and obtain an infrared-shielding film.
The optical characteristics of the infrared-shielding
film are shown in TABLE 2.
The resulting infrared-shielding film had very high
transparency, and the internal state could be clearly viewed
from the exterior. The transmitted color tone was a beautiful
blue color.
[0284]
(Example 30)
Starting materials Rb2CO3, MoO3-H2O, and WO3'H2O were mixed
using a mortar to obtain the desired composition
Rbo.aaMoo.osWo.gsOa. The composition was reduced for one hour at
550°C in an atmosphere (flow) of hydrogen and nitrogen in a
volume ratio of 3:7, and thereafter heat treated for one hour
at 800°C in an N2 atmosphere to obtain an Rb0.33Mo0.osWo.95O3
powder. The powder was dispersed using the same method as
that used in Example 24 to form a film and obtain an infraredshielding
film.
The optical characteristics of the infrared-shielding
film are shown in TABLE 2.
The resulting infrared-shielding film had very high
transparency, and the internal state could be clearly viewed
from the exterior. The transmitted color tone was a beautiful
blue color.
[0285]
(Example 31)
Starting materials Rb2CO3, MoO3-H2O, and WO3-H2O were mixed
using a mortar to obtain the desired composition Rbo.33Mo0.iWo.9O3.
The composition was reduced for one hour at 550°C in an
atmosphere (flow) of hydrogen and nitrogen in a volume ratio
of 3:7, and thereafter heat treated for one hour at 800°C in an
N2 atmosphere to obtain an Rbo.aaMoo.iWo.gOa powder. The powder
was dispersed using the same method as that used in Example 24
to form a film and obtain an infrared-shielding film.
The optical characteristics of the infrared-shielding
film are shown in TABLE 2.
The resulting infrared-shielding film had very high
transparency, and the internal state could be clearly viewed
from the exterior. The transmitted color tone was a beautiful
blue color.
[0286]
(Example 32)
Starting materials Rb2CO3, NbCl5, and WO3-H2O were mixed
using a mortar to obtain the desired composition Rb0.33Nbo.iW0.9O3.
The composition was reduced for one hour at 550°C in an
atmosphere (flow) of hydrogen and nitrogen in a volume ratio
of 3:7, and thereafter heat treated for one hour at 800°C in an
N2 atmosphere to obtain an Rb0.33Nb0.iWo.9O3 powder. The powder
was dispersed using the same method as that used in Example 24
to form a film and obtain an infrared-shielding film.
The optical characteristics of the infrared-shielding
film are shown in TABLE 2.
The resulting infrared-shielding film had very high
transparency, and the internal state could be clearly viewed
from the exterior. The transmitted color tone was a beautiful
blue color.
[0287]
(Example 33)
Starting materials Rb2CO3, TaCls, and WO3-H2O were mixed
using a mortar to obtain the desired composition Rb0.33Ta0.iWo.9O3.
The composition was reduced for one hour at 550°C in an
atmosphere (flow) of hydrogen and nitrogen in a volume ratio
of 3:7, and thereafter heat treated for one hour at 800°C in an
N2 atmosphere to obtain an Rbo.33Ta0.iWo.9O3 powder. The powder
was dispersed using the same method as that used in Example 24
to form a film and obtain an infrared-shielding film.
The optical characteristics of the infrared-shielding
film are shown in TABLE 2.
The resulting Infrared-shielding film had very high
transparency, and the internal state could be clearly viewed
from the exterior. The transmitted color tone was a beautiful
blue color.
[0288]
(Example 34)
Starting materials Na2CO3, MoO3-H2O, and WO3-H2O were mixed
using a mortar to obtain the desired composition
Nao.sMoo.osWo.gsOa. The composition was reduced for one hour at
450°C in an atmosphere (flow) of hydrogen and nitrogen in a
volume ratio of 3:7, and thereafter heat treated for one hour
at 700°C in an N2 atmosphere to obtain an Nao.sHoo.osWo.gsOa powder.
The powder was dispersed using the same method as that used in
Example 24 to form a film and obtain an infrared-shielding
film.
The optical characteristics of the infrared-shielding
film are shown in TABLE 2.
The resulting Infrared-shielding film had very high
transparency, and the internal state could be clearly viewed
from the exterior. The transmitted color tone was a beautiful
blue color.
[0289]
(Example 35)
Starting materials Rb2CO3 and MoO3-H20 were mixed using a
mortar to obtain the desired composition Rb0.33MoO3. The
composition was reduced for one hour at 550°C in an atmosphere
(flow) of hydrogen and nitrogen in a volume ratio of 3:7, and
thereafter heat treated for one hour at 800°C in an N2
atmosphere to obtain an Rb0.33MoO3 powder.
Next, 20 parts by weight of this powder, and 80 parts by
weight of isopropyl alcohol were mixed and dispersed to
prepare a liquid dispersion in which the average dispersion
particle diameter was 200 nm. Next, 100 parts by weight of
this liquid dispersion, and 2 parts by weight of a UV-curing
resin (solid content 100%) as a hard coat were mixed to obtain
a liquid Infrared-shielding nanoparticle dispersion. This
liquid infrared-shielding nanoparticle dispersion was applied
to a PET resin film (HPE-50) using a bar coater to form a film.
This film was dried for 30 seconds at 60"C, the solvent was
allowed to evaporate, and the film was then cured using a high
pressure mercury lamp to obtain an infrared-shielding film.
[0290]
The optical characteristics of the infrared-shielding
film are shown in TABLE 2.
The resulting infrared-shielding film had very high
transparency, and the internal state could be clearly viewed
from the exterior. The transmitted color tone was a beautiful
blue color. The film had electrical conductivity, as shown in
FIG. 2.
[0291]
(Comparative Example 3)
The optical characteristics of PET films which had a
thickness of 50 \m and in which the base materials of Examples
24 to 35 were used were measured. The visible-light
transmlttance was 88.1%, and visible light was adequately
transmitted, but the solar light transmlttance was 88.1%.
Thus, only about 12% of directly Incident solar light rays
were shielded, and the heat-blocking effect was poor.
[0292]
(Comparative Example 4)
WOa-HaO powder was heat treated for one hour at 800°C in
the atmosphere to obtain a WO3 powder.
Next, 20 parts by weight of the powder, 75 parts by
weight of toluene, and 5 parts by weight of a dispersing agent
were mixed and dispersed to obtain a liquid dispersion in
which the average dispersion particle diameter was 80 run.
Next, 10 parts by weight of this liquid dispersion, and 100
parts by weight of a UV-curing resin (solid content 100%) as a
hard coat were mixed to obtain a liquid infrared-shielding
nanoparticle dispersion. This liquid infrared-shielding
nanoparticle dispersion was applied to a PET resin film (HPE-
50) using a bar coater to form a film. This film was dried
for 30 seconds at 60° C, the solvent was vaporized, and the
film was then cured using a high pressure mercury lamp to
obtain an infrared-shielding film.
The optical characteristics were measured. The visiblelight
transmittance was 85.2%, and visible light was
adequately transmitted, but the solar light transmittance was
84.1%. Thus, only about 16% of directly incident solar light
were shielded and the heat-blocking effect was poor.
The resulting infrared-shielding film had very high
transparency, and the internal state could be clearly viewed
from the exterior. However, transmittance in the nearinfrared
region was high, and the material could not function
as an infrared-shielding material. Also, the surface
resistance was 101S Q/square or greater, and the material did
not have electrical conductivity.
[0293]
(Comparative Example 5)
Na2CO3, MoO3-H2O, and WO3-H2O were mixed using a mortar in
an Na:Mo:W molar ratio of 1.5:0.1:0.9. The composition was
reduced for one hour at 550°C in an atmosphere (flow) of
hydrogen and nitrogen in a volume ratio of 3:7, and thereafter
heat treated for one hour at 800°C in an N2 atmosphere. Many
unintended compounds composed of Na and O were generated in
the resulting powder in addition to the intended compound
composed of Na, Mo, W, and O (Nao.sMoo.osWo.gsCh). Therefore,
subsequent measurements were not made.
(Table Removed)
BRIEF DESCRIPTION OF THE DRAWINGS
[0295]
FIG. 1A is a schematic drawing showing the crystal
structure of a tungsten oxide, and is the crystal structure of
Wi8O49 ((010) projection);
FIG. IB is a schematic drawing showing the crystal
structure of a tungsten oxide, and is the crystal structure of
cubic tungsten bronze ((010) projection);
FIG. 1C is a schematic drawing showing the crystal
structure of a tungsten oxide, and is the crystal structure of
tetragonal tungsten bronze ((001) projection);
FIG. ID is a schematic drawing showing the crystal
structure of a tungsten oxide, and is the crystal structure of
hexagonal tungsten bronze ((001) projection);
FIG. 2 is a graph showing a transmission profile of a
visible light transmitting particle-dispersed electrical
conductor formed from WiBO49 electroconductive particles;
FIG. 3 is a graph showing a transmission profile of a
visible light transmitting particle-dispersed electrical
conductor formed from electroconductive particles composed of
hexagonal composite tungsten oxide Cs0.33WO3;
FIG. 4A is an enlarged view showing an SEM image of
aclcular crystals composed of Magneli-phase Wi8O49(WO2.72), which
are the electroconductive particles obtained in Example 1;
FIG. 4B is an overall view of FIG. 4A;
FIG. 5 is an SEM image of crystals shaped as hexagonal
pillars composed of hexagonal tungsten bronze Cso.33WO3f which
are the electroconductive particles obtained in the Example 3;
FIG. 6A is an enlarged view showing an SEM image of
tabular crystals composed of hexagonal tungsten bronze Cs0.35WO3.
which are the electroconductive particles obtained in example
4;
FIG. 6B is an enlarged view showing an SEM image of
tabular crystals composed of hexagonal tungsten bronze Cso.3sWO3,
which are the electroconductive particles obtained in Example
4;
FIG. 7A is an overall view showing an SEM image of
fibrous crystal composed of hexagonal tungsten bronze Rb0.3sWO3,
which are the electroconductive particles obtained in Example
7;
FIG. 75 is an enlarged view of FIG. 7A;
FIG. 8 is a graph showing transmission and reflection
profiles of the Rb0.33W03 film of Example 14;
FIG. 9 is a graph showing transmission and reflection
profiles of the Rb0.33WO3 film of Example 15;
FIG. 10 is a schematic view showing the crystal structure
of composite tungsten oxide nanoparticles having hexagonal
crystals that contain the infrared-shielding nanoparticles of
the present invention; and
)FIG. 11 is a transmission profile of light in a
dispersion film composed of the infrared-shielding
nanoparticles (Rb0.33MoO3) of Example 24.
[KEY]
[0296]
1 WO6 unit
2 element M



We Claim:
1. A transparent electroconductive film composed of a composite oxide expressed by the general formula MEAGW(1-G)OJ (where M is one or more elements selected from Cs, Rb, K, T1, In, Ba, Li, Ca, Sr, Fe, and Sn; A is one or more elements selected from Mo, Nb, Ta, Mn, V, Re, Pt, Pd, and Ti; W is tungsten; O is oxygen; 0 2. The transparent electroconductive film as claimed in Claim 1, characterized in that the composite oxide expressed by said general formula MEAGW(1-G)OJ has a hexagonal crystal structure.
3. A transparent electroconductive article, characterized in that said transparent electroconductive film of claim 1 or 2 is formed on a base material.
4. The transparent electroconductive article as claimed in claim 3, characterized in that a thickness of the transparent electroconductive film ranges from 1 nm or greater to 5,000 nm or less.
5. An infrared-shielding article, characterized in that the transparent electroconductive film of claim 1 or 2 is formed on a base material and has an infrared-shielding function.
6. A method for manufacturing a transparent electroconductive film composed of a composite oxide expressed by the general formula MEAGW(1-G)OJ (where M is one or more elements selected from Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn; A is one or more elements selected from Mo, Nb, Ta, Mn, V, Re, Pt, Pd, and Ti; W is tungsten; O is oxygen; 0 7. The method for manufacturing a transparent electroconductive film as claimed in claim
6,composed of a tungsten oxide expressed by the general formula WyOz (where W is
tungsten, O is oxygen, and 2.2≤z/y≤2.999), and/or a composite tungsten oxide expressed by
the general formula MxWyOz (where M is one or more elements selected from Cs, Rb, K,
Tl, In, Ba, Li, Ca, Sr, Fe, and Sn; W is tungsten; O is oxygen; 0.001≤x/y≤l; and
2.2 (where M is one or more elements selected from Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and

Sn; the element A is one or more elements selected from Mo, Nb, Ta, Mn, V, Re, Pt, Pd, and Ti; 0 8. The method for manufacturing a transparent electroconductive film as claimed in Claim 6 or 7, characterized in that a surfactant is added to the solution composed of the starting material compound or compounds; and the solution is then applied to the base material.
9. The method for manufacturing a transparent electroconductive film as claimed in Claim 7 or 8, characterized in that the solution composed of the starting material compounds is a solution obtained by dissolving tungsten hexachloride in an alcohol when tungsten is used, and/or is an aqueous solution of ammonium tungstate.
10. The method for manufacturing a transparent electroconductive film as claimed in Claim 9, characterized in that a solution obtained by dissolving and mixing the solution obtained by dissolving tungsten hexachloride in alcohol and/or the aqueous solution of ammonium tungstate in claim 9, and a compound having the element M (where M is one or more elements selected from Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn), is applied to the base material directly or after a surfactant has been added.
11. The method for manufacturing a transparent electroconductive film of any one of Claims 6 to 10, characterized in that said heat treatment is performed at a temperature ranging from 100°C or greater to 800°C or less in an atmosphere of a reducing gas, and is subsequently performed as required at a temperature ranging from 550°C or greater to 1,200°C or less in an atmosphere of an inert gas.
12. An infraxed-shielding nanoparticle dispersion obtained by dispersing infrared-shielding nanoparticles in a medium, characterized in that said infrared-shielding nanoparticles include composite oxide nanoparticles expressed by the general formula MEAGW(1.G)OJ (where M is one or more elements selected from Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn; A is one or more elements selected from Mo, Nb, Ta, Mn, V, Re, Pt, Pd, and Ti; W is tungsten; O is oxygen; 0 13. The infrared-shielding nanoparticle dispersion as claimed in Claim 12, characterized in that the composite oxide nanoparticles expressed by said general formula MEAGW(1-G)OJ include one or more nanoparticles selected from composite oxide nanoparticles having a hexagonal crystal structure, composite oxide nanoparticles having a tetragonal crystal structure, and composite oxide nanoparticles having a cubic crystal structure.

14. The Infrared-shielding nanoparticle dispersion as claimed in Claim 12 or 13, characterized in that the composite oxide expressed by said general formula MEAGW(1.G)OJ has a hexagonal structure.
15. The Infrared-shielding nanoparticle dispersion of any of Claims 12 to 14, characterized in that the surfaces of said infrared-shielding nanoparticle dispersion are covered by an oxide composed of one or more elements selected from Si, Ti, Zr, and Al.
16. The infrared-shielding nanoparticle dispersion of any of Claims 12 to 15, characterized in that said medium is resin or glass.
17. The Infrared-shielding nanoparticle dispersion as claimed in Claim 16, characterized in that said resin is one or more resins selected from polyethylene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl alcohol resin, polystyrene resin, polypropylene resin, ethylene-vinyl acetate copolymer, polyester resin, polyethylene terephthalate resin, fluorine resin, polycarbonate resin, acrylic resin, and polyvinyl butyral resin.
18. An infrared-shielding body, characterized in that the infrared-shielding nanoparticle dispersion of any of Claims 12 to 17 is formed in a plate shape, film shape, or thin film shape.
19. The infrared-shielding body as claimed in Claim 18, characterized in that V is 10% or greater, where V is the maximum transmittance of all light rays in the wavelength region of 400 nm to 700 nm; and the minimum transmittance of all light rays in the wavelength region of 700 nm to 2,600 nm is equal to or less than said value V, and is 65% or less.
20. The infrared-shielding body as claimed in Claim 18, characterized in that V is 10% or greater, where V is the maximum transmittance of all light rays in the wavelength region of 400 nm to 700 nm; and surface resistance of the film is 1.0x 1010 Ω/square or less.
21. A method for manufacturing infrared-shielding nanoparticles composed of composite oxide nanoparticles expressed by the general formula MEAGW(1-G)OJ (where M is one or more elements selected from Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn; W is tungsten; O is oxygen; 0 22. The method for manufacturing infrared-shielding nanoparticles as claimed in Claim 21,
characterized in that the starting material of the composite oxide nanoparticles is a tungsten
compound, an element A compound, or an element M compound, and is one or more
compounds selected from oxides, hydrated oxides, chlorides, ammonium salts, carbonates,

nitrates, sulfates, oxalates, hydroxides, peroxides, and simple metals of the corresponding element.
23. The method for manufacturing infrared-shielding nanoparticles as claimed in Claim 21,
characterized in that the starting material of the composite oxide nanoparticles is a powder
obtained by mixing a solution composed of a tungsten compound, an element A compound,
and an element M compound, and then drying the solution.
24. Infrared-shielding nanoparticles manufactured using the method for manufacturing infrared-shielding nanoparticles of any one of Claims 21 to 23, characterized in that the nanoparticles include composite oxide nanoparticles expressed by the general formula MEAGW(1.G)OJ (where M is one or more elements selected from Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn; A is one or more elements selected from Mo, Nb, Ta, Mn, V, Re, Pt, Pd, and Ti; W is tungsten; O is oxygen; 0

Documents:

1926-DELNP-2007-Abstract-(12-07-2012).pdf

1926-delnp-2007-abstract.pdf

1926-DELNP-2007-Claims-(12-07-2012).pdf

1926-delnp-2007-claims.pdf

1926-delnp-2007-Correspondence Others-(06-07-2012).pdf

1926-DELNP-2007-Correspondence Others-(12-07-2012).pdf

1926-DELNP-2007-Correspondence Others-(16-01-2012).pdf

1926-delnp-2007-correspondence-others-1.pdf

1926-delnp-2007-correspondence-others.pdf

1926-delnp-2007-description (complete).pdf

1926-DELNP-2007-Drawings-(12-07-2012).pdf

1926-delnp-2007-drawings.pdf

1926-delnp-2007-form-1.pdf

1926-delnp-2007-form-18.pdf

1926-DELNP-2007-Form-2-(12-07-2012).pdf

1926-delnp-2007-form-2.pdf

1926-DELNP-2007-Form-3-(16-01-2012).pdf

1926-delnp-2007-form-3.pdf

1926-delnp-2007-form-5.pdf

1926-delnp-2007-pct-304.pdf

1926-delnp-2007-pct-311.pdf


Patent Number 258132
Indian Patent Application Number 1926/DELNP/2007
PG Journal Number 50/2013
Publication Date 13-Dec-2013
Grant Date 06-Dec-2013
Date of Filing 12-Mar-2007
Name of Patentee SUMITOMO METAL MINING CO., LTD.,
Applicant Address 11-3, SHIMBASHI 5-CHOME, MINATO-KU,TOKYO,1058716 JAPAN
Inventors:
# Inventor's Name Inventor's Address
1 TAKEDA HIROMITSU C/O ICHIKAWA RESEARCH LABORATORY OF SUMITOMO METAL MINING CO.,LTD.OF 18-5, NAKAKOKUBUN 3-CHOME, ICHIKAWA-SHI, CHIBA, 2720835 JAPAN
2 ADACHI KENJI C/O ICHIKAWA RESEARCH LABORATORY OF SUMITOMO METAL MINING CO.,LTD.OF 18-5, NAKAKOKUBUN 3-CHOME, ICHIKAWA-SHI, CHIBA, 2720835 JAPAN
PCT International Classification Number H01B 5/14
PCT International Application Number PCT/JP2005/015948
PCT International Filing date 2005-08-31
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2004-344775 2004-11-29 Japan
2 2004-251956 2004-08-31 Japan
3 2005-122668 2005-04-20 Japan