Title of Invention

PROCESS FOR PRODUCTION OF ORGANIC-INORGANIC HYBRID HYDROGEL

Abstract The present invention provides a production process of an organic/inorganic composite hydrogel, which demonstrates superior mechanical properties, by uniformly dispersing a clay mineral in an organic polymer over a wide range of clay mineral content, and a dried form thereof, to be produced easily in a short period of time. The production process of an organic/inorganic composite hydrogel of the present invention comprises reacting a water-soluble organic monomer (a) in the presence of a water-swellable clay mineral (b) by irradiating with an energy beam in a solution in which a non-water-soluble polymerization initiator (d) is dispersed in an aqueous medium (c).
Full Text

[TECHNICAL FIELD]
[0001]
The present invention relates to a production process of
an organic/inorganic composite hydrogel having a
three-dimensional network structure comprising a polymer of a
water-soluble organic monomer and a water-swellable clay
mineral, a coated film of an organic/inorganic composite
hydrogel and a cell culture substrate comprising that coated
film, and a dried coated film of an organic/inorganic composite
hydrogel and an antifogging coated film comprising that dried
coated film,
[BACKGROUND ART]
[0002]
Polymer composites referred to as nanocomposites have
conventionally been prepared by compounding an organic polymer
such as polyamide, polystyrene, polypropylene, polyimide or
polyurethane with clay. Since the resulting polymer composite
is finely dispersed in a clay layer having a large aspect ratio,
the elastic modulus, heat deflection temperature, gas

permeability, burning rate and so forth are known to be
effectively improved.
[0003]
An organic/inorganic composite hydrogel having a
three-dimensional mesh structure composed of a polymer of a
water-soluble acrylic monomer and a water-swellable clay
mineral has been disclosed as an example of a nanocomposite
material having particularly superior mechanical properties
(see, for example, Japanese Unexamined Patent Application,
First Publication No. 2002-053762 and Japanese Unexamined
Patent Application, First Publication No. 2004-143212). Since
this organic/inorganic composite hydrogel has superior
mechanical properties not found in other gels, it is expected
to be applied in various applications. In order to deploy the
application thereof in various applications, the
organic/inorganic composite hydrogel is frequently required to
be formed into a coated film such as a thin film or film, formed
into a pattern, or formed into a laminated structure, and in
such cases, the composite hydrogel is easily molded into these
shapes and forms by producing an organic/inorganic composite
hydrogel using an energy beam.
[0004]
As an example of a production process of the prior art,
a process has been disclosed in which an acrylamide or

acrylamide derivative and a (meth)acrylic acid ester and so
forth are polymerized by heating' or irradiation with
ultraviolet light in the presence of a water-swellable clay
mineral in an agueous medium and an aqueous polymerization
initiator (see, for example, Japanese Unexamined Patent
Application, First Publication No. 2002-053762 and Japanese
Unexamined Patent Application, First Publication No.
2004-143212). However, in the case of using a water-soluble
peroxide for the polymerization initiator and carrying out the
polymerization reaction by irradiating with ultraviolet light
as in the process disclosed here, there were cases in which the
mechanical properties of the resulting organic/inorganic
composite hydrogel were not adequately obtained as well as cases
in which elution of linear polymer occurred. In addition, since
a water-soluble peroxide is used for the polymerization
initiator, since the polymer composite is polymerized by
allowing to stand undisturbed for several tens of minutes to
more than ten hours at a constant temperature such as room
temperature in the state in which oxygen in the polymer solution
has been removed, there has been a need to simplify the
production process as well as shorten the production time.
[0005]
These problems occur particularly prominently when forming
a coated film, thereby preventing the obtaining of an

organic/inorganic composite hydrogel coated film having
adequate mechanical properties and resulting in a desire to
realize an organic/inorganic composite hydrogel coated film
suitable for deployment in various applications.
[DISCLOSURE OF THE INVENTION]
[Problems to be Solved by the Invention]
[0007]
An object of the present invention is to provide a
production process of an organic/inorganic composite hydrogel
having superior mechanical properties in a production process
of an organic / inorganic composite hydrogel using an energy
beam, and an antifogging coated film and cell culture substrate
that use the resulting organic/inorganic composite hydrogel.
[Means for Solving the Problems]
[0008]
As a result of conducting extensive studies to solve the
aforementioned problems, the inventors of the present invention
found that by dispersing a non-water-soluble polymerization
initiator (d) in an aqueous medium (c) and reacting, in the
resulting dispersion , a water-soluble monomer (a) by
irradiating with an energy beam in the presence of a
water-swellable clay mineral, the reaction is completed nearly
instantaneously while being resistant to the effects of oxygen.
Moreover, it was also found that by dispersing a

non-water-soluble photopolymerization initiator (d) in the
aqueous medium (c) , the non-water-soluble photopolymerization
initiator (d) is interposed around the water-swellable clay
mineral (b) when the water-swellable clay mineral (b) is present
in the dispersion. When the water-soluble organic monomer (a)
is polymerized in such an environment, the polymerization
reaction begins from the photopolymerization initiator
interposed around the water-swellable clay mineral (b) , bonding
between a polymer of the water-soluble organic monomer (a) and
the water-swellable clay mineral (b) proceeds favorably, and
a three-dimensional network structure is formed in which the
polymer of the water-soluble organic monomer (a) is crosslinked
between the water-swellable clay mineral (b) , thereby allowing
the production of an organic/inorganic composite hydrogel
having superior mechanical properties.
[0009]
Namely, the present invention provides a production
process of an organic/inorganic composite hydrogel having a
three-dimensional network structure composed of a polymer of
a water-soluble organic monomer (a) and a water-swellable clay
mineral (b), wherein
a non-water-soluble polymerization initiator (d) is
dispersed in an aqueous medium (c), and the water-soluble
organic monomer (a) is reacted in the resulting dispersion by

irradiating with an energy beam in the presence of the
water-swellable clay mineral (b).
[0010]
In addition, the present invention provides a production
process of a coated film comprising an organic/inorganic
composite hydrogel having a three-dimensional network
structure composed of a polymer of a water-soluble organic
monomer (a) and a water-swellable clay mineral (b), wherein
an energy beam-curable composition (X), containing a
dispersion of a non-water-soluble polymerization initiator (d)
dispersed in the water-soluble organic monomer (a), the
water-swellable clay mineral (b) and an aqueous medium (c) , is
coated onto a substrate followed by irradiating with an energy
beam.
[0011]
In addition, the present invention provides a production
process of a thin film comprising a dried organic/inorganic
composite hydrogel having a three-dimensional network
structure composed of a polymer of a water-soluble monomer (a)
and a water-swellable clay mineral (b) , wherein
an energy beam-curable composition (X), containing a
dispersion of a non-water-soluble polymerization initiator (d)
dispersed in the water-soluble monomer (a), the water-swellable
clay mineral (b) and an aqueous medium (c), is coated onto a

substrate followed by irradiating with an energy beam to form
an organic/inorganic composite hydrogel coated film, and
removing the solvent from the organic/inorganic composite
hydrogel coated film.
[0012]
In addition, the present invention provides a culture
substrate comprising an organic/inorganic composite hydrogel
having a three-dimensional network structure composed of a
polymer of a water-soluble organic monomer (a) and a
water-swellable clay mineral (b).
[0013]
In addition, the present invention provides an antif ogging
material comprising a dried organic/inorganic composite
hydrogel having a three-dimensional network structure composed
of a polymer of a water-soluble organic monomer (a) and a
water-swellable clay mineral (b).
[Effects of the Invention]
[0014]
According to the production process of the present
invention, since the production process is resistant to the
effects of oxygen when polymerizing an organic/inorganic
composite hydrogel, equipment and steps for removing oxygen are
not required, thereby allowing the organic/inorganic composite
hydrogel to be easily produced. Moreover, the

organic/inorganic composite hydrogel can be produced in an
extremely short period of time as a result of polymerizing by
irradiating with an energy beam. In addition, as a result of
having the characteristics of being resistant to the effects
of oxygen on polymerization and polymerization being able to
be completed in an extremely short period of time, the resulting
organic/inorganic composite hydrogel and dried product thereof
is able to realize superior mechanical properties and
flexibility by uniformly dispersing the clay mineral in the
organic polymer over a wide range of clay mineral content.
[0015]
Since the organic/inorganic composite hydrogel and dried
product thereof of the present invention exhibits superior
mechanical properties and flexibility of the organic/inorganic
composite hydrogel despite being a coated film by uniformly
dispersing the clay mineral in an organic polymer over a wide
range of clay mineral content, they are useful as materials for
medical and nursing care devices as well as various types of
industrial materials.
[0016]
Since the culture substrate comprising the
organic/inorganic composite hydrogel of the present invention
has superior flexibility and toughness, it is able to stably
transport cultured cells while retaining its shape even when

transporting cultured cells along with the substrate.
Moreover, in the case of carrying out co-culturing and so forth
following initial cell culturing, culturing can be repeated
without being contaminated by culture liquid or chemicals. In
particular, since cell culture substrates in which
hydrophilicity and hydrophobicity reversibly change according
to the external environment exhibit superior adhesion with
cells under hydrophobic conditions, they are able to
effectively culture and grow cells, and since they are able to
lower adhesion with cells under hydrophilic conditions, cell
can be detached without using a protein hydrolase such as
trypsin or chemicals, thereby enabling cells to be recovered
easily without damaging cells or causing separation or
contamination by the substrate. Moreover, since the change
from hydrophobicity to hydrophilicity or from hydrophilicity
to hydrophobicity occurs rapidly, the effects on cells during
changes in temperature and other parameters of the external
environment are low.
[0017]
Since the antifogging coated film comprising the dried
organic/inorganic composite hydrogel.of the present invention
exhibits superior mechanical properties and antifogging
properties by uniformly dispersing a clay mineral in an organic
polymer over a wide range of clay mineral content while

simultaneously having favorable adhesion with various types of
substrates, it can be used as a material for medical and nursing
care devices as well as various types of industrial materials.
[BEST MODE FOR CARRYING OUT THE INVENTION]
[0018]
[Organic/Inorganic Composite Hydrogel Production Process]
The water-soluble organic monomer (a) used in the present
invention has the property of dissolving in water, and together
with interacting with the water-swellable clay mineral (b)
capable of uniformly dispersing in water, is polymerized by
being irradiated with radiation, and preferably has a
functional group capable of forming a hydrogen bond, ionic bond,
coordinate bond or covalent bond and so forth with a clay mineral.
Specific examples of water-soluble organic monomers having a
functional group include water-soluble organic monomers having
an amide group, amino group, ester group, hydroxyl group,
tetramethyl ammonium group, silanol group or epoxy group, with
water-soluble organic monomers having an amide group being
preferable. In addition, water as referred to in the present
invention includes mixed solvents of organic solvents miscible
with water having water as a main component thereof. In
particular, water-soluble acrylic monomers are preferable, and
the use of a water-soluble acrylic monomer allows the
non-water-soluble initiator to be more finely and uniformly

dispersed, and the obtaining of an organic/inorganic composite
hydrogel having more superior properties and is resistant to
the effects of oxygen during polymerization by an energy beam.
[0019]
Preferable examples of such water-soluble organic monomers
(a) that can be used include N-substituted acrylamide
derivatives, N,N-disubstituted acrylamide derivatives,
N-substituted methacrylamide derivatives and
N,N-disubstituted methacrylamide derivatives, with specific
examples including N-isopropyl acrylamide, N-isopropyl
methacrylamide, N-n-propyl acrylamide, N-n-propyl
methacrylamide, N-cyclopropyl acrylamide, N-cyclopropyl
methacrylamide, N-ethoxyethyl acrylamide, N-ethoxyethyl
methacrylamide, N-tetrahydrofurfuryl acrylamide,
N-tetrahydrofurfuryl methacrylamide, N-ethyl acrylamide,
N-ethyl-N-methyl acrylamide, N,N-diethyl acrylamide,
N-methyl-N-n-propyl acrylamide, N-methyl-N-isopropyl
acrylamide, N-acryloyl piperidine and N-acryloyl pyrrolidine.
[0020]
The acrylic monomers of formulas (1) to (6) below are used
even more preferably.
[Chemical Formula 1]



(wherein, R1 represents a hydrogen atom or methyl group, R2 and
R3 respectively and independently represent a hydrogen atom or
alkyl group having 1 to 3 carbon atoms, R4 represents an alkyl
group having 1 to 2 carbon atoms, and n is 1 to 9) .
[0021]
One or more types of the aforementioned water-soluble
organic monomers may be used as a mixture according to the

required mechanical properties, chemical properties and so
forth.
[0022]
In addition, other copolymerizable monomers can also be
used in combination to a degree that does not have an effect
on the properties of the organic/inorganic composite hydrogel,
examples of which include acrylic monomers having an anionic
group such as a sulfone group or carboxyl group, acrylic
monomers having a cationic group such as a quaternary ammonium
group, acrylic monomers having amphoteric ionic groups such as
a quaternary ammonium group and a phosphate group, acrylic
monomers having amino acid residues such as a carboxyl group
and an amino group, acrylic monomers having a sugar residue,
acrylic monomers having a hydroxyl group, acrylic monomers
having a polyethylene glycol or polypropylene glycol chain,
amphipathic acrylic monomers having both a hydrophilic chain
such as polyethylene glycol and a hydrophobic group such as a
nonylphenyl group, polyethylene glycol diacrylate and
N,N'-methylene bisacrylamide.
[0023]
A polymer of the water-soluble organic monomer (a) in the
present invention is able to form an organic/inorganic
composite hydrogel of a stable form by forming a
three-dimensional network structure with the water-swellable

clay mineral (b) and acrylic compounds comprised of the
previously listed monomers or vinyl compounds and so forth can
be used. Examples of polymers of the water-soluble organic
monomer (a) include poly(N-isopropylacrylamide),
poly(N-n-propylacrylamide),
poly(N-cyclopropylmethacrylamide) ,
poly(N-isopropylmethacrylamide),
poly(N-n-propylmethacrylamide),
poly(N-ethoxyethylacrylamide),
poly(N-ethoxyethylmethacrylamide) ,
poly(N-tetrahydrofurfurylacrylamide),
poly(N-tetrahydrofurfurylmethacrylamide) ,
poly(N-ethylacrylamide), poly(N,N-diethylacrylamide),
poly(N-acryloylpiperidine) and poly(N-acryloylpyrrolidine).
[0024]
An example of the water-swellable clay mineral (b) used
in the present invention is a swellable clay mineral capable
of separating into a layered form, and is preferably a clay
mineral capable of swelling and uniformly dispersing in water
or a mixed solvent of water and an organic solvent, and
particularly preferably an inorganic clay mineral capable of
uniformly dispersing in a molecular form (single layer) or level
close thereto in water. For example, water-swellable smectite
or water-swellable mica can be used, specific examples of which

include water-swellable hectorite, water-swellable
montmorillonite, water-swellable saponite, and
water-swellable synthetic mica, containing sodium as an
interlayer ion. These clay minerals may also be used as a
mixture.
[0025]
When producing the organic/inorganic composite hydrogel
of the present invention, the weight ratio (b)/(a) of the
water-swellable clay mineral (b) to the water-soluble organic
monomer (a) is preferably 0.01 to 10, more preferably 0.03 to
5, and particularly preferably 0.05 to 3. If the weight ratio
(b)/(a) is less than 0.01, the mechanical properties of the
resulting organic/inorganic composite hydrogel tend to be
inadequate, while if the ratio exceeds 10, it becomes difficult
to disperse the clay mineral.
[0026]
There are no particular limitations on the aqueous medium
(c) used in the present invention provided it is able to contain
the water-soluble organic monomer (a) and the water-swellable
clay mineral (b), and allows the obtaining of an
organic/inorganic composite hydrogel having satisfactory
mechanical properties as a result of polymerization by an energy
beam. For example, it may be an aqueous solution containing
water and a solvent and/or other compound miscible with water,

and is able to contain, in particular, a preservative or
antimicrobial, colorant, fragrance, enzyme, protein, sugars,
amino acids, cells, DNA, salts, water-soluble organic solvent,
surfactant or leveling agent.
[0027]
Examples of the non-water-soluble polymerization
initiator (d) used in the present invention include
acetophenones such as p-tert-butyl trichloroacetophenone,
benzophenones such as 4,4'-bisdimethylaminobenzophenone,
ketones such as 2-methylthioxanthone, benzoin ethers such as
benzoin methyl ether, a-hydroxyketones such as
hydroxycyclohexyl phenyl ketone,phenyl glyoxylates such as
methyl benzoyl formate, and metallocenes.
[0028]
Non-water-soluble refers to the amount of the
polymerization initiator that dissolves in water being 0.5% by
weight or less. If solubility in water is excessively high,
the mechanical properties of the resulting organic/inorganic
composite hydrogel tend to be inadequate.
[0029]
In the production process of the present invention, after
dispersing the non-water-soluble polymerization initiator (d)
in the aqueous medium (c), it is important to polymerize this
dispersion in the presence of both the organic monomer (a) and

the water-swellable clay mineral (b) in that dispersion by
irradiating with an energy beam. At this time, the
polymerization initiator (d) is preferably dispersed in the
aqueous medium (c) dissolved in a solvent (e) . As a result of
employing this method, an organic/inorganic composite hydrogel
having satisfactory mechanical properties can be obtained by
irradiating with an energy beam. Conversely, in the case of
using a water-soluble polymerization initiator, there are cases
in which the mechanical properties of the resulting
organic/inorganic composite hydrogel decrease or elution of linear polymer occurs.
[0030]
A water-soluble solvent capable of dissolving the
non-water-soluble polymerization initiator (d) or an acrylic
monomer (e-1) that dissolves the non-water-soluble
polymerization initiator (d) and has a hydrophile-lipophile
balance (HLB) value of 8 or more can be used for the solvent
(e) of the present invention. This HLB value is the value
determined according to the Davis method ("Surfactants -
Properties, Applications and Chemoecology", F. Kitahara, etal.
ed., Kodansha Publishing, 1979, p. 24-27). Examples of the
solvent (e) include polypropylene glycol diacrylates such as
tripropylene glycol diacrylate; polyethylene glycol
diacrylates, polypropylene glycol acrylates such as

pentapropylene glycol acrylate; polyethylene glycol acrylates,
methoxypolyethylene glycol acrylates such as methoxyethyl
acrylate and methoxytriethylene glycol acrylate; nonylphenoxy
polyethylene glycol acrylates, N-substituted acrylamides such
as dimethyl acrylamide; hydroxyethyl acrylate and
hydroxypropyl acrylate. If the HLB value of the acrylic monomer
used for the solvent (e) is 8 or more, solubility or dispersivity
in the aqueous medium (c) is superior, thereby making this
preferable. One or more types of these acrylic monomers can
be used as a mixture.
[0031]
In addition, a water-soluble solvent (e2) capable of
dissolving the non-water-soluble polymerization initiator (d)
and having at least a certain degree of water solubility can
be used "for the solvent (e) of the present invention. A
water-soluble solvent here preferably refers to a solvent of
which 50 g or more is able to be dissolved in 100 g of water.
If the solubility in water thereof is less than 50 g, the
dispersivity of the non-water-soluble polymerization
initiator (d) in the aqueous medium (c) decreases, thereby
resulting in cases in which the mechanical properties of the
resulting organic/inorganic composite hydrogel are low.
[0032]
Examples of the water-soluble solvent (e2) include amides

such as dimethylacetoamide and dimethylformamide; alcohols
such as methanol and ethanol, tetrahydrofuran, and
dimethylsulfoxide. These solvents may also be used as a
mixture.
[0033]
The weight ratio (d)/(e) of the non-water-soluble
polymerization initiator (d) and the solvent (e) in a solution
in which the polymerization initiator (d) is dissolved in the
solvent (e) is preferably 0. 001 to 0 .1 and more preferably 0 . 01
to 0.05. If this ratio is 0.001 or more, since an adequate
amount of radicals are generated by irradiation with an energy
beam, the polymerization reaction is able to proceed favorably,
and if the ratio if 0.1 or less, there is substantially no
occurrence of discoloration or odor caused by the initiator,
while also enabling costs to be reduced.
[0034]
In addition, the dispersed amount of solution in which the
polymerization initiator (d) is dissolved in the solvent (e)
relative to the total weight of the water-soluble organic
monomer (a) , the water-swellable clay mineral (b) , the aqueous
solvent (c), polymerization initiator (d) and the organic
solvent (e) is preferably 0.1 to 5% by weight and more preferably .
0 . 2 to 2% by weight. If this dispersed amount is 0.1% by weight
more, polymerization is adequately initiated, while if this

amount is less than 5% by weight, problems such as the formation
of linear polymers not involved in the organic/inorganic
composite hydrogel, the generation of odor caused by an increase
in the amount of polymerization initiator in the gel, and
re-aggregation of the initially dispersed polymerization
initiator or solution of the polymerization initiator and the
solvent (e), can be reduced, thereby making this preferable
since it allows the obtaining of a homogeneous
organic/inorganic composite hydrogel.
[0035]
In order to obtain an organic/inorganic composite hydrogel
in the present invention having satisfactory mechanical
properties, the solution in which the polymerization initiator
(d) is dissolved in the solvent (e) is preferably dispersed in
the aqueous medium (c) at 1 µm or less, particularly preferably
at 0.1 µm or less, and most preferably at 0.01 µm or less. If
dispersed at 1 µm or less, the reaction solution easily becomes
homogeneous, thereby making this preferable since the
homogeneity and transparency of the organic/inorganic
composite hydrogel can be improved.
[0036]
Examples of energy beams used in the present invention
include an electron beam, gamma rays, X-rays, ultraviolet rays
and visible light. In particular, ultraviolet rays are used

preferably in consideration of the simplicity of the apparatus
and ease of handling. The intensity of the irradiated
ultraviolet rays is preferably 10 to 500 mW/cm2, and the
irradiation time is typically about 0.1 to 200 seconds.
Although oxygen acts as an inhibitor of polymerization in the
case of ordinary radical polymerization by heating, in the
present invention, it is not necessary to prepare the solution
and carry out polymerization by irradiation with an energy beam
in an atmosphere isolated from oxygen, but rather these can be
carried out in an air atmosphere. However, there are cases in
which irradiating with ultraviolet rays in an inert gas
atmosphere is desirable since it allows the polymerization rate
to be further increased.
[0037]
The production process of the inorganic/organic composite
hydrogel of the present invention consists of shaping a reaction
solution containing the water-soluble organic monomer (a) , the
water-swellable clay mineral (b) , the aqueous medium (c) , the
polymerization initiator (d) and the solvent (e) into an
arbitrary form (such as a plate, sheet, thin film, rod, sphere,
fiber or hollow fiber) and irradiating with an energy beam to
polymerize the water-soluble organic monomer (a) .. In addition,
an organic/inorganic composite hydrogel can also be produced
in the form of a single sheet or continuous sheets by using a

belt-shaped support.
[0038]
Examples of supports that can be used include metal, ceramic,
glass, plastic, fabric, non-woven fabric, paper and wood. The
sheet-like gel may ultimately be peeled from the support or it
may used while still integrated with the support.
[0039]
Moreover, an organic/inorganic composite hydrogel having
an arbitrary pattern can also be produced if the aforementioned
reaction solution is coated onto a support and then irradiated
with an energy beam through a mask. An ultrafine pattern can
be obtained on the micrometer level or lower.
[00.40]
In particular, the production process of the present
invention is suitable for forming a coated film comprising an
organic/inorganic composite hydrogel, and a coated film
comprising an organic/inorganic composite hydrogel having
superior mechanical properties can be easily produced by
coating an energy beam-curable composition (X), containing a
dispersion in which the non-water-soluble polymerization
initiator (d) is dispersed in the water-soluble organic monomer
(a), the water-swellable clay mineral (b) and the aqueous medium
(c), onto a substrate followed by irradiating with an energy
beam.

[0041]
In addition, a coated film comprising a dried
organic/inorganic composite hydrogel can be produced by producing the aforementioned coated film, washing as necessary,
and removing the solvent by drying and so forth.
[0042]
[Cell Culture Substrate]
The cell culture substrate of the present invention
comprises an organic/inorganic composite hydrogel having a
three-dimensional network structure composed of a polymer of
the water-soluble organic monomer (a) and the water-swellable
clay mineral (b), and preferably comprises the
organic/inorganic composite hydrogel formed by irradiation
with an energy beam.
. [0043]
The water-soluble organic monomer (a) and the
water-swellable clay mineral (b) used here are the same as those
previously described. A water-soluble organic monomer that
imparts a polymer having both water solubility or
hydrophilicity for absorbing water and hydrophobicity is
particularly effective for the water-soluble organic monomer
(a) since cultured cells can be easily separated from the
resulting cell culture substrate. A water-soluble organic
monomer that enables the hydrophilicity and hydrophobicity of

the polymer in an aqueous solution to change with temperature,
pH, solute concentration and solvent composition is used
particularly preferably. More specifically, in the case of
temperature, for example, polymers having a lower critical
solution temperature (LCST) at which it becomes hydrophobic at
or above the critical temperature (Tc), and polymers having an
upper critical solution temperature (UCST) at which it becomes
hydrophilic at or above the Tc are used preferably. In addition,
in the case of solute concentration, for example, polymers that
become hydrophobic at or above a certain concentration of sodium
chloride in the solvent and become hydrophilic below that
concentration at a certain temperature are also used preferably.
Moreover, in the case of solvent composition, for example,
polymers that become hydrophobic when the concentration of
methanol relative to water in the solvent reaches a certain
concentration, and become hydrophilic below that certain
concentration at a certain temperature are also used
preferably.
[0044]
Since the organic/inorganic composite hydrogel used in the
cell culture substrate of the present invention is such that
the polymer of the water-swellable clay mineral (b) and the
water-soluble organic monomer (a) has a three-dimensional
network structure, it has the characteristic of allowing cells

to retain their shape without being destroyed when detached from
the organic/inorganic composite hydrogel following culturing.
In addition, in the case it is necessary to transport the cells
to the location of a subsequent experiment following culturing,
the organic/inorganic composite hydrogel used in the cell
culture substrate of the present invention enables the cells
to be transported without destroying the cultured cell sheet.
This organic/inorganic composite hydrogel is able to realize
a tensile modulus of 1 kPa or more, tensile strength of 20 kPa
or more, and fracture elongation of 50% or more at a moisture
content of 90%, and a composite hydrogel having these properties
can be used preferably. In addition, a tensile modulus of 5
kPa or more, tensile strength of 50 kPa or more and fracture
elongation of 50% or more are more preferable, while a tensile
modulus of 10 kPa or more, tensile strength of 80 kPa or more
and fracture elongation of 100% or more are even more preferable.
An organic/inorganic composite hydrogel having such mechanical
properties allows the obtaining of a surface status suitable
for cell culturing. In addition, an organic/inorganic
composite hydrogel having such mechanical properties under
conditions of a water content of 90% retains superior mechanical
properties even in a state of exhibiting hydrophobicity during
cell culturing, and demonstrates superior shape stability,
handling, mobility and so forth regardless of its form following

cell culturing.
[0045]
This organic/inorganic composite hydrogel has
hydrophilicity and hydrophobicity corresponding to external
environmental conditions due to the polymer of the
water-soluble organic monomer (a) that forms a
three-dimensional network structure. Consequently, a cell
culture substrate comprising this organic/inorganic composite
hydrogel is able to preferably culture cells and allow cultured
cells to be detached and recovered both easily and rapidly
without causing destruction of the cultured cells or separation
and contamination by the substrate.
[0046]
Although the inorganic/organic composite hydrogel used in
the cell culture substrate of the present invention is obtained
by polymerization of the water-soluble organic monomer (a) as
a result of irradiating the water-soluble organic monomer (a)
with radiation in the presence of the water-swellable clay
mineral uniformly dispersed in water, polymerization by
irradiation is ordinarily carried out using a polymerization
initiator. At this time, the polymerization initiator is
preferably uniformly dispersed, and is more preferably
uniformly dispersed on the surface or in the vicinity thereof
of the water-swellable clay mineral (b) uniformly dispersed in

water. As a result of irradiating such an aqueous solution with
radiation, an organic/inorganic composite hydrogel can be
obtained in which the water-swellable clay mineral (b) is
uniformly dispersed, thereby allowing the obtaining of a cell
culture substrate having superior cell culturing performance.
An example of a method for uniformly dispersing the
polymerization initiator is described above.
[0047]
There are no particular limitations on the cells capable
of being cultured using the cell culture substrate of the
present invention provided they are human or animal tissue cells,
and examples of such cells include vascular cells, fibroblasts,
muscle cells, nerve cells, chondrocytes, osteoblasts, liver
cells, pancreas cells and cornea cells. Among these, vascular
endothelial cells, skin fibroblasts, hepatic parenchymal cells,
hepatic cancer cells and chondrocytes are used preferably. In
particular, the present invention can be preferably used to
culture, for example, skin fibroblasts, vascular endothelial
cells and chondrocytes.
[0048]
In addition to being used alone, the organic/inorganic
composite hydrogel used in the cell culture substrate of the
present invention is also used by coating onto a support having
a smooth surface or irregular surface such as metal, ceramic,

plastic, fabric, non-woven fabric, paper or wood. In addition,
the composite hydrogel can be formed into various shapes to
realize enhanced mechanical properties, and can be used in the
form of a sheet, fibers, hollow fibers or spheres. The polymer
hydrogel coated onto the support may be ultimately peeled from
the support or may be used integrated with the support.
[0049]
In the production of the cell culture substrate of the
present invention, cell culture substrates having various sizes
and shapes can be prepared by changing the shape of the
polymerization vessel at the time of polymerization or cutting
the gel after polymerization. For example, cell culture
substrates can be prepared having an arbitrary shape such as
fibers, rods, disks, cylinders, hollow shapes, spirals or
spheres. In addition, the cell culture substrate can also be
produced in the form of fine particles by using a method such
as having a commonly used surfactant present during the
polymerization reaction. In addition, the cell culture
substrate of the present invention is preferably used by
layering over a non-hydrophilic support such as a plastic or
glass Petri dish routinely used for cell culturing. Such a
laminated member may be polymerized on the support and used
directly for cell culturing, or it may be polymerized in another
vessel followed using for cell culturing after filling onto a

substrate surface.
The organic/inorganic composite hydrogel used in the cell
culture substrate of the present invention has the
characteristic of being able to be formed at an arbitrary-
thickness when formed into various shapes, and when used by
coating onto a support in particular, the thickness following
irradiation is preferably 1000 µm or less and more preferably
10 to 500 µm for reasons such as ease of preparation, reduction
of the amount of residual monomer following polymerization by
irradiation, and ease of separation from the support.
[0050]
A commonly known, ordinary organic crosslinking agent may
also be used during production of the organic/inorganic
composite hydrogel for the purpose of improving the properties
thereof. There are no particular limitations on the organic
crosslinking agent used, and can be selected according to the
purpose of use. Examples of organic crosslinking agents that
can be used include bifunctional compounds such as
N,N'-methylene bisacrylamide, N,N'-propylene bisacrylamide,
di(acrylamidomethyl) ether, 1,2-diacrylamidoethylene glycol,
1,3-diacryloyl ethylene urea, ethylene diacrylate,
N,N' -diallyl tartar diamide and N,N' -bisacrylyl cystamine; and
trifunctional compounds such as triallyl cyanurate or triallyl
isocyanurate.

[0051]
The cell culture substrate of the present invention can
be obtained in the form of a dried cell culture substrate by
forming the organic/inorganic composite hydrogel on a support
and washing as necessary followed by drying while affixed to
the support. In addition, a dried cell culture support can also
be obtained by peeling the organic/inorganic composite hydrogel
formed on the support from the support, washing as necessary
and then drying.
[0052]
A surface status suitable for cell culturing can be obtained
for the cell culture substrate of the present invention by
converting to a dry form. Moreover, when using as a cell culture
substrate, by immersing the dried cell culture substrate in a
liquid cell culture medium, the liquid culture medium can be
absorbed by the cell culture substrate, thereby easily
obtaining a cell culture substrate having a moisture content
suitable for cell culturing. The water content at this time
differs from the water content of the cell culture substrate
prior to drying, and by changing the ratio of the polymer of
the water-soluble organic monomer and the clay mineral in the
organic/inorganic composite hydrogel that composes the cell
culture substrate, and reversibly changing the hydrophilic and
hydrophobic status of the organic/inorganic composite hydrogel,

the water content can be arbitrarily controlled over a wide
range. In particular, by immersing the organic/inorganic
composite hydrogel in a medium at a higher temperature than the
lower critical solution temperature of the organic/inorganic
composite hydrogel, the water content thereof is controlled to
a water content suitable for cell culturing, and that having
a weight ratio of solvent to the dried cell culture substrate
of 0.01 to 5 is used preferably, while that having a ratio of
0 . 01 to 1 is used more preferably. If the weight ratio is within
this range, the surface of the organic/inorganic composite
hydrogel in terms of smoothness, water content and so forth is
suitable for cell culturing, and is able to demonstrate superior
culturing characteristics for various types of cells.
[0053]
Although it is necessary to sterilize the cell culture
substrate prior to use for cell culturing, this sterilization
step can be carried out with irradiation, autoclaving or gas
sterilization and so forth of the organic/inorganic composite
hydrogel. Among these, irradiation with gamma rays and so forth
is used more preferably, and irradiation of a dried polymer
hydrogel can be carried out particularly preferably. As a
result, the cell culture substrate can be sterilized without
significantly decreasing the properties of the
organic/inorganic composite hydrogel and without allowing

substances to remain that have a detrimental effect on cells.
[0054]
When producing the organic/inorganic composite hydrogel,
in addition to the water-soluble organic monomer, polymer or
low molecular weight compounds can be contained as additives
within a range that does not impair the effects of the present
invention. Examples of such compounds that can be added include
cell adhesion factors such as collagen and hyaluronic acid, cell
growth factors and hydroxyapatite particles.
[0055]
As has been described above, the cell culture substrate
of the present invention is comprised of an organic/inorganic
composite hydrogel having a three-dimensional network
structure obtained by polymerizing the water-soluble organic
monomer (a) in the presence of the water-swellable clay mineral
(b) uniformly dispersed in water. Consequently, that in which
the clay mineral is uniformly dispersed in the
organic/inorganic composite hydrogel is obtained over a wide
range of the clay mineral content, and since the
organic/inorganic composite hydrogel can be controlled to a
state that is suitable for cell adhesion and spreading, it has
superior culturing performance. In addition, as a result of
having superior flexibility and toughness, the shape of
cultured cells can be retained even when transporting with the

substrate, thereby making it possible to stably transport
cultured cells. Moreover, in the case of, for example,
co-culturing following initial cell culturing, culturing can
be repeated without contamination by culture liquid or
chemicals.
[0056]
Since a cell culture substrate comprising a polymer
hydrogel in which hydrophilicity and hydrophobicity change
reversibly according to the external environment demonstrates
superior adhesion with cells under hydrophobic conditions,
cells can be suitably cultured and grown. In addition, since
adhesion with cells can be decreased under hydrophilic
conditions, cells can be detached without using a protein
hydrolase such as trypsin or chemical agent, thereby enabling
cells to be recovered easily without causing destruction of the
cells or separation and contamination by the substrate.
Moreover, since the change from hydrophobicity to
hydrophilicity or from hydrophilicity to hydrophobicity occurs
rapidly, the effect on cells is minimal when changes such as
temperature are made to the external environment.
[0057]
In particular, an organic/inorganic composite hydrogel
coated film obtained by polymerizing the water-soluble organic
monomer (a) with an energy beam is able to preferably

demonstrate the superior properties described above even while
in the form of a thin film.
[0058]
[Antifogging Material]
The antifogging material of the present invention is
comprised of a dried organic/inorganic composite hydrogel
having a three-dimensional network structure composed of a
polymer of the water-soluble organic monomer (a) and the
water-swellable clay mineral (b) , and can be easily produced
according to the aforementioned production process. The
antifogging material of the present invention is predicted to
have extremely superior mechanical properties (surface
hardness), transparency and antifogging performance due to
electrostatic interaction, interaction of the hydrophobic
portion, interaction by hydrogen bonds and coordinate bonds or
a combination of interactions thereof between the polymer of
the water-soluble organic monomer (a) and the water-swellable
clay mineral (b).
[0059]
The water-soluble organic monomer (a) and the
water-swellable clay mineral (b) used here are the same as
previously described, and a water-soluble acrylic monomer can
be used particularly preferably for the water-soluble organic
monomer (a) due to the ease of production by energy beam

polymerization and the properties of the resulting gel.
[0060]
In particular, acrylamide, methacrylamide or a derivative
thereof (such as N- or N,N-substituted (meth)acrylamide) can
be used preferably, while at least one type of monomer selected
from the group consisting of the acrylic monomers represented
by the aforementioned formulas (1) to (6) can be used more
preferably. As a result of using these acrylic monomers, since
the non-water-soluble polymerization initiator used during
polymerization can be dispersed more finely and uniformly, an
antifogging material having more superior properties can be
obtained that is resistant to the effects of oxygen during
polymerization by an energy beam.
[0061]
In the antifogging material of the present invention, the
thickness of the dried organic/inorganic composite hydrogel is
preferably within the range of 1 to 500 µm, more preferably 1
to 100 urn and even more preferably 3 to 50 µm. Since a dried
organic/inorganic composite hydrogel of this thickness allows
facilitates the obtaining "of a homogeneous film of adequate
strength while also decreasing susceptibility to deformation
of the gel during drying and peeling from the substrate, the
surface layer of the antifogging material is able to demonstrate
superior strength and surface antifogging performance.

[0062]
In addition, since the dried organic/inorganic composite
hydrogel can be easily layered on other substrates, antifogging
performance can be preferably imparted to the substrate surface.
In layering on another substrate, a coated film can be formed
easily by carrying out energy beam polymerization on the other
substrate.
[0063]
The substrate used in the antifogging material of the
present invention is preferably a transparent substrate from
the viewpoint of maintaining antifogging performance, namely
transparency. Examples of substrates include glass substrates
such as glass or mirrored substrates, and transparent plastics
such as polycarbonate or polyethylene.
[0064]
The dried organic/inorganic composite hydrogel formed on
the substrate can be in direct contact with the surface of the
transparent substrate and integrated therewith, or the two can
be integrated with a transparent primer layer or adhesive layer
interposed there between. The adhesive layer is preferably a
hydrophobic polymer comprising a polymer of a hydrophobic
acrylic monomer in consideration of ease of production of the
adhesive layer and the adhesive strength thereof.
[0065]

The hydrophobic polymer is preferably a hydrophobic
polymer comprising a hydrophobic acrylic monomer due to the
superior adhesion thereof with the dried organic/inorganic
composite hydrogel. Specific examples of hydrophobic acrylic
monomers include acrylic acid esters and epoxy esters of acrylic
acid having one or more acryloyl groups in a molecule thereof,
and urethane oligomers having one or more acryloyl groups in
a molecule thereof.
[0066]
The antifogging material of the present invention can be
prepared to have a wide range of hardness of the dried
organic/inorganic composite hydrogel as is required in terms
of wear resistance and so forth, and the surface hardness
thereof preferably has a surface pencil hardness of HB or higher
and particularly preferably H or higher from the viewpoint of
ordinary handling ease.
[0067]
The antifogging performance of the antifogging material
of the present invention can be adjusted by suitably adjusting
the degree of hydrophilicity (water contact angle) of the
surface of the dried organic/inorganic composite hydrogel.
The range for particularly preferable use as an antifogging
material is preferably a water contact angle of 40° or less and
more preferably 20° or less for the surface of the dried

organic/inorganic composite hydrogel. The degree of
hydrophilicity of the dried gel layer can be adjusted by
suitably selecting a copolymer of the polymer of the
water-soluble organic monomer (a) and another hydrophobic
polymer.
[0068]
Since the antifogging material of the present invention
is a homogeneous film in which a clay mineral is uniformly
dispersed in an organic polymer over a wide range of content
of the clay mineral, it has superior mechanical properties
(surface hardness) , antifogging performance and transparency.
Moreover, since the dried organic/inorganic composite hydrogel
has superior adhesion with the substrate, an antifogging
material in which the dried organic/inorganic composite
hydrogel and the hydrophobic polymer are covalently bonded in
particular has extremely superior adhesion. In addition,
since this antifogging material allows polymerization to be
completed in an extremely short period of time while also being
able to form a homogeneous film, it has the characteristic of
having extremely high production efficiency, and is used in
medical and nursing care devices as well as various types of
industrial materials.
[Examples]
[0069]

Although the following provides a more detailed
explanation of the present invention through examples thereof,
the scope of the present invention is not limited to these
examples alone.
[0070]
Example 1 - Production of Organic/Inorganic Composite
Hydrogel
2 g of N,N-dimethyl acrylamide (Kohjin Co., Ltd.) in the
form of the water-soluble organic monomer (a) , 0. 8 g of Laponite
XLG (Rockwood Additives Ltd.) in the form of the clay mineral
(b) and 20 g of water in the form of the aqueous medium (c) were
uniformly mixed to prepare a reaction solution (1).
[0071]
98 g of polyoxypropylene monoacrylate ("Brenmer AP-400",
NGF Corp.) in the form of the solvent (e) and 2 g of
1-hydroxycyclohexyl phenyl ketone ("Irgacure 184", Ciba
Specialty Chemicals Ltd.) in the form of the non-water-soluble
polymerization initiator (d) were uniformly mixed to prepare
solution (1).
[0072]
50 µl of the solution (1) were added to the entire volume
of the aforementioned reaction solution (1) and uniformly
dispersed with an ultrasonic homogenizer followed by sealing
in a glass tube having an inner diameter of 5. 5 mm and irradiating

with ultraviolet light having an ultraviolet intensity of 40
mW/cm2 at 365 nm for 120 seconds to polymerize the N,N-dimethyl
acrylamide and produce a rod-shaped organic/inorganic
composite hydrogel (1).
[0073]
When the gel produced in the manner described above was
analyzed using a tensile tester (Model AGS-H, Shimadzu Corp.) ,
the breaking point stress was found to be 60 KPa and the breaking
point strain was found to be 1950%. The resulting gel was also
visually determined to be colorless and transparent.
[0074]
Example 2 - Production of Organic/Inorganic Composite
Hydrogel
2.3 g of N-isopropyl acrylamide (Kohjin Co., Ltd.) in the
form of the water-soluble organic monomer (a) , 0 . 8 g of Laponite
XLG (Rockwood Additives Ltd.) in the form of the clay mineral
(b) and 20 g of water in the form of the aqueous medium (c) were
uniformly mixed to prepare a reaction solution (2).
[0075]
95 g of 2-hydroxyethyl acrylate (Wako Pure Chemical
Industries, Ltd.) in the form of the solvent (e) and 5 g of
1-hydroxycyclohexyl phenyl ketone ("Irgacure 184", Ciba
Specialty Chemicals Ltd.) in the form of the non-water-soluble
polymerization initiator (d) were uniformly mixed to prepare

solution (2).
[0076]
100 µl of solution (2) were added to the entire volume of
the aforementioned reaction solution (2) and uniformly
dispersed with an ultrasonic homogenizer followed by sealing
in a glass tube having an inner diameter of 5. 5 mm and irradiating
with ultraviolet rays having an ultraviolet intensity of 40
mW/cm2 at 365 nm for 120 seconds to polymerize the N-isopropyl
acrylamide and produce a rod-shaped organic/inorganic
composite hydrogel (2).
[0077]
When the gel produced in the manner described above was
analyzed using a tensile tester (Model AGS-H, Shimadzu Corp.) ,
the breaking point stress was found to be 125 KPa and the breaking
point strain was found to be 1200%. The resulting gel was also
visually determined to be colorless and transparent.
[0078]
When this gel was immersed for 165 hours in water at 20°C,
the gel swelled to about 400% of its initial mass. In addition,
when this swollen gel was immersed for 24 hours in water at 50°C,
the gel de-swelled and returned to about 35% of its initial mass.
[0079]
Example 3 - Production of Organic/Inorganic Composite
Hydrogel

2.6 g of 2-methoxyethyl acrylate (Wako Pure Chemical
Industries, Ltd.) in the form of the water-soluble organic
monomer (a), 1.6 g of Laponite XLG (Rockwood Additives Ltd.)
in the form of the clay mineral (b) and 20 g of water in the
form of the aqueous medium (c) were uniformly mixed to prepare
a reaction solution (3).
[0080]
95 g of N,N-dimethylacetoamide (Wako Pure Chemical
Industries, Ltd.) in the form of the solvent (e) and 5 g of
1-hydroxycyclohexyl phenyl ketone ("Irgacure 184", Ciba
Specialty Chemicals Ltd.) in the form of the non-water-soluble
polymerization initiator (d) were uniformly mixed to prepare
solution (3).
[0081]
80 µ1 of the solution (3) were added to the entire volume
of the aforementioned reaction solution (3) and uniformly
dispersed with an ultrasonic homogenizer followed by coating
onto a glass plate to a thickness of 150 µm using a bar coater
and irradiating with ultraviolet rays having an ultraviolet
intensity of 40 mW/cm2 at 365 nm for 120 seconds to polymerize
the 2-methoxyethyl acrylate and produce a coated film of an
organic/inorganic composite hydrogel (3). The resulting gel
was visually observed to be colorless and transparent.
[0082]

Example 4 - Production of Organic/Inorganic Composite
Hydrogel
2.8 g of 4-acryloylmorpholine (Wako Pure Chemical
Industries, Ltd.) in the form of the water-soluble organic
monomer (a), 1.6 g of Laponite XLG (Rockwood Additives Ltd.)
in the form of the clay mineral (b) and 20 g of water in the
form of the aqueous medium (c) were uniformly mixed to prepare
a reaction solution (4).
[0083]
92 g of polyoxypropylene monoacrylate ("Brenmer AP-400",
NOF Corp.) in the form of the solvent (e) and 8 g of
1-hydroxycyclohexyl phenyl ketone ("Irgacure 184", Ciba
Specialty Chemicals Ltd.) in the form of the non-water-soluble
polymerization initiator (d) were uniformly mixed to prepare
solution (4).
[0084]
80 µl of the solution (4) were added to the entire volume
of the aforementioned reaction solution (4) and the solution
was uniformly dispersed with an ultrasonic homogenizer followed
by coating onto a glass plate to a thickness of 200 µm using
a bar coater, irradiating with ultraviolet rays having an
ultraviolet intensity of 40 mW/cm2 at 365 nm for 120 seconds
through a polyethylene terephthalate (PET) mask (line width:
approx. 200 µm, having black lines drawn to roughly 5 cm in

length) to polymerize the 4-acryloylmorpholine and removing the
uncured (black line) portion by rinsing with water to produce
a coated film of an organic/inorganic composite hydrogel (4)
having grooves in the pattern as the black lines of the mask.
[0085]
The gel produced in the manner described above was visually
observed to be colorless and transparent.
In addition, observation of the grooves with a light
microscope revealed the groove width to be about 200 µm.
[0086]
Comparative Example 1
2 g of N,N-dimethyl acrylamide (Kohjin Ltd.) in the form
of a water-soluble organic monomer, 0.8 g of Laponite XLG
(Rockwood Additives Ltd.) in the form of a clay mineral, 0.02
g of potassium peroxodisulfate (Wako Pure Chemical Industries,
Ltd.) in the form of a water-soluble polymerization initiator
(peroxide) and 20 g of water in the form of an aqueous medium
were uniformly mixed in air isolated from oxygen to prepare a
reaction solution (l').
[0087]
The aforementioned reaction solution (1') was sealed in
a glass tube having an inner diameter of 5.5 mm in air not
isolated from oxygen and allowed to stand undisturbed for 15
hours in a water bath at 20°C. However, since all of the

aforementioned procedures were not isolated from oxygen, the
solution only became slightly viscous and a gel was not
obtained.
[0088]
Comparative Example 2
2.3 g of N-isopropyl acrylamide (Kohjin Ltd.) in the form
of a water-soluble organic monomer, 0.8 g of Laponite XLG
(Rockwood Additives Ltd.) in the form of a clay mineral, 0.2
g of 2-hydroxy-l-[4-(2-hydroxyethoxy)phenyl]-1-propane
("Irgacure 2959", Ciba Specialty Chemicals Ltd.) in the form
of a water-soluble polymerization initiator and 20 g of water
in the form of an aqueous medium were uniformly mixed in air
isolated from oxygen to prepare a reaction solution (2').
[0089]
The aforementioned reaction solution (2') was sealed in
a glass tube having an inner diameter of 5.5 mm and polymerized
by irradiating with ultraviolet light having an ultraviolet
intensity of 40 mW/cm2 at 365 nm for 120 seconds. The resulting
gel was visually observed to have a milky white color and be
opaque. Although the gel was attempted to be analyzed using
a tensile tester (Model AGS-H, Shimadzu Corp.), testing was
unable to be carried out due to the excessively weak strength
of the gel.
[0090]

On the basis of the results of the aforementioned Examples
1 to 4 and Comparative Examples 1 and 2, according to the
production process of the present invention, an
organic/inorganic composite hydrogel that demonstrates
superior mechanical properties, flexibility and transparency
was clearly determined to be able to be produced in extremely
short period of time, without having to remove oxygen, and over
a wide range of a clay mineral content, by uniformly dispersing
the clay mineral in an organic polymer.
[0091]
Example 5 - Production of Cell Culture Substrate
2.2 3 g of N-isopropyl acrylamide (Kohjin Ltd.) in the form
of the water-soluble organic monomer (a) , 0.8 g of Laponite XLG
(Rockwood Additives Ltd.) in the form of the clay mineral (b)
and 20 g of water in the form of the aqueous medium (c) were
uniformly mixed to prepare a reaction solution (5).
[0092]
98 g of polyoxypropylene monoacrylate ("Brenmer AP-400",
NOF Corp.) in the form of the solvent (e) and 2 g of
1-hydroxycyclohexyl phenyl ketone ("Irgacure.184", Ciba
Specialty Chemicals Ltd.) in the form of the non-water-soluble
polymerization initiator (d) were uniformly mixed to product
a solution (5).
[0093]

50 µl of the solution (5) were added to the entire volume
of the aforementioned reaction solution (5) and uniformly
dispersed with an ultrasonic homogenizer followed by coating
that solution onto a polyethylene terephthalate (PET) film to
a thickness of 200 µm using a bar coater and irradiating with
ultraviolet rays having an ultraviolet intensity of 40 mW/cm2
at 365 nm for 120 seconds to polymerize the water-soluble
organic monomer and obtain a sheet-like organic/inorganic
composite hydrogel (5).
[0094]
After the resulting sheet-like organic/inorganic
composite hydrogel (5) was slightly immersed in water at.20°C
and allowed to swell to adjust to a water content of 90%, the
sheet-like organic/inorganic composite hydrogel (5) was peeled
from the PET film so as not to damage the gel. The peeled
sheet-like organic/inorganic composite hydrogel was then cut
to a size of 1 cm x 5 cm and attached to a tensile tester
("Benchtop Universal Tester AGS-H", Shimadzu Corp.) so as hot
to slide in the chuck. As a result of then carrying out tensile
testing at a distance between evaluation points of 30 mm and
pulling speed of 100 mm/min, the tensile fracture strength was
found to be 95 kPa and the braking elongation was found to be
1010%. After carefully wiping off all water adhered to the
surface of this sheet-like organic/inorganic composite

hydrogel (5), the contact angles of the surface of the
sheet-like organic/inorganic composite hydrogel (5) relative
to water were measured at 20°C and 50°C using a contact angle
measuring apparatus ("CA-X200", Kyowa Interface Science Co.,
Ltd.) . The water contact angle at 20°C was 30° and the water
contact angle at 50°C was 60°. On the basis of these results,
the resulting sheet-like organic/inorganic composite hydrogel
was confirmed to demonstrate both hydrophilicity and
hydrophobicity according to temperature conditions.
[0095]
On the other hand, the sheet-like organic/inorganic
composite hydrogel (5) was then immersed for 2 days in 2 liters
of ultrapure water at 20°C, removed after the hydrogel was
allowed to swell, immersed again for 2 days in 1 liter of
ultrapure water at 50°C and then removed after the hydrogel was
allowed to de-swell. After repeating this washing
purification procedure 3 times, the purified sheet-like
organic/inorganic composite hydrogel (5) was cut to a diameter
of 8 cm to obtain a cell culture substrate (A) . This was then
transferred to a cell, culture dish ("Falcon 3003",
Becton-Dickinson Labware Inc.), covered and allowed to stand
undisturbed at 37°C. Furthermore, all procedures from
purification to transfer of the cell culture substrate (A) to

the cell culture dish were carried out in a Clean Bench.
[0096]
[Culturing Test]
Cells were cultured using the cell culture dish containing
the cell culture substrate (A) obtained in the manner described
above. Cancer cell line cells HepG2 derived from human liver
epithelial cells (Dainippon Sumitomo Pharma Co., Ltd.) were
used for the cultured cells. Culturing was carried out using
minimum essential Eagle's medium (Sigma) containing 10% fetal
calf serum (ICN) (containing as additives pyruvic acid (ICN)
and non-essential amino acids (ICN)) in a 37°C incubator
containing 5% carbon dioxide. In addition, two dishes
containing the cell culture substrate (A) were prepared, and
simultaneously inoculated under the same conditions. One week
after inoculation, one of the dishes containing the cell culture
substrate (A) was allowed to stand undisturbed for 5 minutes
in a 20°C constant temperature chamber followed by observing
the surface thereof with a light microscope to confirm that the
cells had adhered to the cell culture substrate (A) and grown
sufficiently. The cell culture substrate (A) together with the
cultured cells were removed from the dish containing the other
cell culture substrate (A) used for culturing, and transferred
to a tissue culture dish containing minimum essential Eagle's
medium containing 10% fetal calf serum pre-warmed to a

temperature of 20°C. After covering and allowing to stand
undisturbed for 10 minutes at 20°C, the cells were able to be
detached from the cell culture substrate (A) by grabbing the
cells that had grown on the cell culture substrate (A) with a
tweezers. At this time, there was no damage to the cell culture
substrate (A), and the cell culture substrate (A) was not
observed to be adhered to the detached cells. After separating
into individual cells by treating the detached cells with
trypsin-EDTA, a count of viable cells as determined by Trypan
blue staining confirmed that the 2.0 x 106 cells at the start
of culturing had increased to 1.9 x 108 cells after culturing.
[0097]
Example 6 - Culturing Test
Cells were cultured using the cell culture dish containing
the cell culture substrate (A) obtained in the aforementioned
Example 5. Normal human skin fibroblasts (Dainippon Sumitomo
Pharma Co., Ltd.) were used for the cultured cells. Culturing
was carried out using CS-C medium (Dainippon Sumitomo Pharma
Co., Ltd.) in a 37°C incubator containing 5% carbon dioxide.
In addition, two dishes containing the cell culture substrate
(A) were prepared, and simultaneously inoculated under the same
conditions. One week after inoculation, one of the dishes
containing the cell culture substrate (A) was allowed to stand
undisturbed for 5 minutes in a 20°C constant temperature chamber

followed by observing the surface thereof with a light
microscope to confirm that the cells had adhered to the cell
culture substrate (A) and grown sufficiently. The cell culture
substrate (A) together with the cultured cells were removed from the dish containing the other cell culture substrate (A) used
for culturing, and transferred to a tissue culture dish
containing CS-C medium pre-warmed to a temperature of 20°C.
After covering and allowing to stand undisturbed for 10 minutes
at 20°C, the cells were able to be detached from the cell culture
substrate (A) in the form of a sheet by grabbing the cells that
had grown on the cell culture substrate (A) with a tweezers.
At this time, there was no damage to the cell culture substrate
(A) , and the cell culture substrate (A) was not observed to be
adhered to the sheet-like cells. After separating into
individual cells by treating the removed sheet-like cells with
trypsin-EDTA, a count of viable cells as determined by Trypan
blue staining confirmed that the 2.5 x 106 cells at the start
of culturing had increased to 9.1 x 107 cells after culturing.
[0098]
Example 7 - Production of Cell Culture Substrate
A nearly colorless and transparent, homogeneous sheet-like
organic/inorganic composite hydrogel (6) was synthesized in the
same manner as Example 5 with the exception of changing the
amount of Laponite XLG added to 1.6 g. When the contact angle

substrate (B) comprised of the dried sheet-like
organic/inorganic composite hydrogel (6) .
[0099]
[Culturing Test]
HepG2 cells were cultured using the cell culture substrate
(B) obtained in this manner using the same cells, media and
culturing conditions and in the same manner as Example 1. When
the surface was observed with a light microscope using the same
method as Example 1 one week after inoculation of the cells,
the cells were confirmed to be adhered and adequately growing
on the cell culture substrate (B) . After culturing the cells
using another dish containing the cell culture substrate (B)
in the same manner as Example 1, the cell culture substrate (B)
together with the cultured cells were removed from the dish
containing the cell culture substrate (B) , and transferred to
a tissue culture dish containing minimum essential Eagle's
medium containing 10% fetal calf serum pre-warmed to a
temperature of 20°C. After covering and allowing to stand
undisturbed for 10 minutes at 20°C, the cells were able to be
detached from the cell culture substrate (B) by grabbing the
cells that had grown on the cell culture substrate (B) with a
tweezers. At this time, there was no damage to the cell culture
substrate (B), and the cell culture substrate (B) was not
observed to be adhered to the detached cells. A count of viable

cells carried out in the same manner as Example 1 confirmed that
the 2.0 x 106 cells at the start of culturing had increased to
1.3 x 107 cells after culturing.
In addition, when the hydrogel was dried and the resulting
dried hydrogel was immersed in the media used in the experiment
described above followed by holding for 24 hours in a 37°C
incubator, the hydrogel returned to a hydrogel having a moisture
content of 30%.
[0100]
Comparative Example 3
Cells were cultured using a cell culture dish ("Falcon 3003"
not subjected to any surface treatment. Culturing was carried
out using the same cells, media and culturing conditions and
in the same manner as Example 1. When the surface of the dish
was observed with a light microscope one week after the start
of culturing, the cells were confirmed to be adhered and growing.
After the dish used for this culturing was placed in an incubator
at 20°C and allowed to stand undisturbed for 10 minutes, although
the cells were attempted to be removed from the dish, there was
no detachment of the cells whatsoever. In addition, when the
cultured cells were detached using trypsin in accordance with
known methods, the cells ended up breaking up into individual
cells and were unable to be removed in the form of a sheet.
[0101]

with respect to water at 20°C and 50°C was measured in the same
manner as Example 1 using the resulting sheet-like
organic/inorganic composite hydrogel (6), the water contact
angle at 20°C was found to be 29° and that at 50°C was found to
be 45°, thus confirming that the resulting sheet-like
organic/inorganic composite hydrogel (6) exhibits both
hydrophilicity and hydrophobicity according to temperature
conditions. The resulting sheet-like organic/inorganic
composite hydrogel (6) was then immersed for 2 days in 1 liter
of ultrapure water at 20°C and removed after the hydrogel was
allowed to swell, followed by immersing for 2 days in 1 liter
of ultrapure water at 50°C and removed after the hydrogel was
allowed to de-swell. After repeating this washing
purification procedure 3 times, the edges of the purified
sheet-like organic/inorganic composite hydrogel (6) were
immobilized with clips so as not to deform the four sides thereof
and allowed to dry for 3 days inside a Clean Bench. The
resulting dried hydrogel was placed in a gas-impermeable
plastic bag and sealed and irradiated with gamma rays (radiation
source: Cobalt 60, Radia Industry Co., Ltd.). The radiation
dose was 25 kGy. There was no particular deformation or
discoloration observed in the dried hydrogel following
irradiation. Following irradiation with gamma rays, the dried
hydrogel was cut to a diameter of 8 cm to obtain a cell culture

As shown in the aforementioned Examples 5 to 7, due to its
flexibility and toughness, the cell culture substrate of the
present invention enabled cells to be recovered without
damaging the cells and without allowing the cells to be
contaminated by the substrate during separation and recovery
of cultured cells. Moreover, since the hydrophilicity and
hydrophobicity of the cell culture substrate reversibly change
according to the external environment, the cultured cells were
able to be recovered rapidly. On the other hand, as shown in
Comparative Example 3, cell culture substrates of the prior art
resulted in severing of bonds between the cells and substrate
during cell recovery, while also causing bonds between cells
to be severed, thereby preventing the cells from being removed
in a proliferating state. Moreover, in Comparative Example 4,
the shape of the culture substrate was unable to be maintained.
[0104]
Example 8 - Production of Antifogging Coated Film
2 g of N,N-dimethyl acrylamide (Kohjin Co., Ltd.) in the
form of the water-soluble organic monomer (a) , 0 . 8 g of Laponite
XLG (Rockwood Additives Ltd.) in the form of the clay mineral
(b) and 20 g of water in the form of the aqueous medium (c) were
uniformly mixed to prepare a reaction solution (7).
[0105]
98 g of polyoxypropylene monoacrylate ("Brenmer AP-400",

Comparative Example 4
An organic crosslinked hydrogel was polymerized in the same
manner as Example 1 with the exception of not using a claymineral
and adding an organic crosslinking agent after adding NIPA
monomer at 5 mol% of the monomer. N, N' -methylene bisacrylamide
(Wako Pure Chemical Industries, Ltd.) was used as is for the
organic crosslinking agent. As a result, a sheet-like hydrogel
was obtained that became white at 20°C. Although the resulting
sheet-like hydrogel was transferred to a cell culture dish after
purifying in the same manner as Example 1, since the hydrogel
was extremely brittle, purification and transfer were difficult.
In addition, the contact angle of this sheet-like hydrogel was
4 9° when held at a temperature of 50°C.
[0102]
Next, cells were cultured in the same manner as Example
2 using the cell culture dish containing this sheet-like
hydrogel. When a portion of the sheet-like hydrogel in the dish
was removed one week after the start of culturing and stained
with Trypan blue, the cells were not confirmed to be growing
on the sheet-like hydrogel. In addition, although this
sheet-like hydrogel was attempted to be removed from the dish,
the sheet-like hydrogel ended up breaking and was unable to be
removed.
[0103]

NOF Corp.) in the form of the solvent (e) and 2 g of
1-hydroxycyclohexyl phenyl ketone ("Irgacure 184", Ciba
Specialty Chemicals Ltd.) in the form of the non-water-soluble
polymerization initiator (d) were uniformly mixed to prepare
solution (7).
[0106]
50 µl of the solution (7) were added to the entire volume
of the aforementioned reaction solution (7) and uniformly
dispersed with an ultrasonic homogenizer followed by coating
onto a 3 mm thick glass plate to a thickness of 150 µm using
a bar coater and irradiating with ultraviolet rays having an
ultraviolet intensity of 40 mW/cm2 at 365 nm for 120 seconds
to polymerize the N,N-dimethyl acrylamide and produce an
organic/inorganic composite hydrogel (7) on the glass plate.
[0107]
The aforementioned organic/inorganic composite hydrogel
(7) was dried for 20 minutes with a hot air dryer at 80°C to
produce an antifogging coated film (X) laminated on the glass
plate.
[0108]
The antifogging coated film (X) produced in the manner
described above was visually determined to be colorless and
transparent. The surface hardness on the dried gel side of the
antifogging coated film (X) as measured using the pencil method

was H. The water contact angle as measured using a contact angle
measuring apparatus ("CA-X200", Kyowa Interface Science Co.,
Ltd.) was 31°.
[0109]
[Antifogging Performance Test]
The antifogging coated film (X) prepared in the manner
described above was placed over a 200 ml beaker containing 100
ml of hot water at 60°C so that the dried gel was facing downward
and the film was confirmed not to fog for 1 minute. The dried
gel did not swell and did not separate from the glass after
testing.
[0110]
. Example 9 - Production of Antifogging Coated Film
2.3 g of N-isopropyl acrylamide (Kohjin Co., Ltd.) in the
form of the water-soluble organic monomer (a), 1.28 g of
Laponite XLG (Rockwood Additives Ltd.) in the form of the clay
mineral (b) and 20 g of water in the form of the aqueous medium
(c) were uniformly mixed to prepare a reaction solution (8).
[0111]
95 g of 2-hydroxyethyl acrylate (Wako Pure Chemical
Industries, Ltd.) in the form of the solvent (e) and 5 g of
1-hydroxycyclohexyl phenyl ketone ("Irgacure 184", Ciba
Specialty Chemicals Ltd.) in the form of the non-water-soluble
polymerization initiator (d) were uniformly mixed to prepare

solution (8) .
[0112]
100 µl of the solution (8) were added to the entire volume
of the aforementioned reaction solution (8) and uniformly
dispersed with an ultrasonic homogenizer followed by coating
onto a polycarbonate plate (thickness: 3 mm) pre-coated with
an adhesive layer in the form of hydrophobic urethane acrylate
(V-4263, Dainippon Ink & Chemicals Inc.) containing 2% by weight
of 1-hydroxycyclohexyl phenyl ketone to a thickness of 20 urn,
and irradiating with ultraviolet rays having an ultraviolet
intensity of 40 mW/cm2 at 365 nm for 120 seconds to polymerize
the adhesive layer and the N-isopropyl acrylamide and produce
an organic/inorganic composite hydrogel (8) on a substrate
having an adhesive layer.
[0113]
The aforementioned organic/inorganic composite hydrogel
(8) was dried for 20 minutes with a hot air dryer at 80°C to
produce an antifogging coated film (Y).
[0114]
The antifogging coated film (Y) produced in the manner
described above was visually determined to be colorless and
transparent. The surface hardness on the dried gel side of the
substrate as measured using the pencil method was H. The water
contact angle as measured using a contact angle measuring

apparatus ("CA-X200", Kyowa Interface Science Co., Ltd.) was
30°.
[0115]
[Antifogging Performance Test]
The antifogging coated film (Y) prepared in the manner
described above was placed over a 200 ml beaker containing 100
ml of hot water at 60°C so that the dried gel was facing downward
and the film was confirmed not to fog for 1 minute. The dried
gel did not swell and did not separate from the polycarbonate
plate after testing.
- [0116]
Example 10 - Production of Antifogging Coated Film
2.8 g of acryloyl morpholine (Kohjin Co., Ltd. ) in the form
of the water-soluble organic monomer (a) , 1.6 g of Laponite XLG
(Rockwood Additives Ltd.) in the form of the clay mineral (b)
and 20 g of water in the form of the aqueous medium (c) were
uniformly mixed to prepare a reaction solution (9).
[0117]
95 g of N,N-dimethylacetoamide (Wako Pure Chemical
Industries, Ltd.) in the form of the solvent (e) and 5 g of
1-hydroxycyclohexyl phenyl ketone ("Irgacure 184", Ciba
Specialty Chemicals Ltd.) in the form of the non-water-soluble
polymerization initiator (d) were uniformly mixed to prepare
solution . (9).

[0118]
80 µl of the solution (9) were added to the entire volume
of the aforementioned reaction solution (9) and uniformly
dispersed with a mixer followed by coating that solution onto
a 200 urn thick polyethylene terephthalate (PET) sheet to a
thickness of 150 µm using a bar coater and irradiating with
ultraviolet rays having an ultraviolet intensity of 40 mW/cm2
at 365 nm for 120 seconds to polymerize the acryloyl morpholine
and produce an organic/inorganic composite hydrogel (9) on a
PET substrate.
[0119]
The aforementioned organic/inorganic composite hydrogel
(9) was dried for 20 minutes with a hot air dryer at 80°C to
produce an antifogging coated film (Z).
[0120]
The antifogging coated film (Z) produced in the manner
described above was visually determined to be colorless and
transparent. The surface hardness on the dried gel side of the
substrate as measured using the pencil method was 2H. The water
contact angle as measured using a contact angle measuring
apparatus ("CA-X200", Kyowa Interface Science Co., Ltd.) was
33°.
[0121]
[Antifogging Performance Test]

The antifogging coated film (Z) prepared in the manner
described above was placed over a 200 ml beaker containing 100
ml of hot water at 60°C so that the dried gel was facing downward
and the film was confirmed not to fog for 1 minute. The dried
gel did not swell and did not separate from the polycarbonate
plate after testing.
[0122]
Comparative Example 5
4 . 5 g of methyl methacrylate (Wako Pure Chemical Industries,
Ltd.), 3.5 g of butyl methacrylate (Wako Pure Chemical
Industries, Ltd.), 1 g of hydroxyethyl methacrylate (Kyoeisha
Chemical Co., Ltd.), 0.3 g of acrylic acid (Wako Pure Chemical
Industries, Ltd.), 0.2 g of methacrylic acid (Wako Pure Chemical
Industries, Ltd.) and 10 g of 2-propanol (Wako Pure Chemical
Industries, Ltd.) were uniformly mixed to prepare an acrylic
monomer composition.
[0123]
0.4 g of Laponite XLG (Rockwood Additives Ltd.) in the form
of the clay mineral (B) were dispersed in a mixed solution of
4.8 g of 2-propanol (Wako Pure Chemical Industries, Ltd.) and
4.8 g of water to prepare a clay mineral dispersion.
[0124]
0.2 g of the acrylic monomer composition prepared in the
manner described above, 5 g of the clay mineral dispersion, 20

g of 2-propanol and 30 g of water were uniformly mixed to prepare
an antifogging composition 1.
[0125]
The aforementioned antifogging composition 1 was then
coated onto a glass plate using a bar coater having a coated
film thickness of 10 urn followed by drying by heating for 10
minutes in a hot air dryer at 90°C to produce an antifogging
coated film.
[0126]
The antifogging coated film produced in the manner
described above was visually determined to be white and foggy.
This was due to the clay not having dissolved in the mixture
of water and 2-propanol. The surface hardness of the
antifogging coated film as measured with the pencil method was
B. The water contact angle as measured using a contact angle
measuring apparatus ("CA-X200", Kyowa Interface Science Co.,
Ltd.) was 32°.
[0127]
When the antifogging coated film prepared in the manner
described above was placed over a 200 ml beaker containing 100
ml of hot water, at 60°C so that the coated film was facing
downward and allowed to stand undisturbed for 1 minute, fogging
was observed on the side of the dried gel layer.
[0128]

As indicated in Examples 8 to 10, the antifogging coated
film comprising a dried organic/inorganic composite hydrogel
having a three-dimensional network structure composed of a
polymer of a water-soluble organic monomer and a water-swellable clay mineral of the present invention
demonstrated superior antifogging performance., high
mechanical properties and heat resistance, superior adhesion
with a substrate and demonstrated superior transparency. On
the other hand, the antifogging coated film indicated in
Comparative Example 5, comprising a dried gel not having a
three-dimensional network structure composed of a polymer of
a water-soluble organic monomer and water-swellable clay
mineral, demonstrated inferior transparency and antifogging
performance.
[INDUSTRIAL APPLICABILITY]
Since the production process of the present invention
eliminates the need for a step for removing oxygen, it enables
an organic/inorganic composite hydrogel to be easily produced,
and since the hydrogel can be produced in an extremely short
period of time by irradiating with an energy beam, an
organic/inorganic composite hydrogel can be advantageously
obtained in terms of production equipment and cost.
In addition, since the organic/inorganic composite
hydrogel coated film, dried coated film and antifogging coated

film of the present invention demonstrate superior mechanical
properties, flexibility and so forth as a result of a clay
mineral being uniformly dispersed in an organic polymer, they
are useful as materials for medical and nursing care devices
as well as various types of industrial materials. In particular,
since a cell culture substrate composed of the
organic/inorganic composite hydrogel of the present invention
has superior flexibility and toughness while also being able
to rapidly respond to changes in the external environment, it
has considerable industrial significance since cells can be
recovered easily without having an effect on the cells.

We Claim:
1. A production process of an organic/inorganic composite hydrogel having a
three-dimensional network structure composed of a polymer of a water-soluble organic
monomer (a) selected from N-substituted acrylamide derivatives, N,N-disubstituted
acrylamide derivatives, N-substituted methacrylamide derivatives and N,N-disubstituted
methacrylamide derivatives selected from the group consisting of N-isopropyl acrylamide, N-
isopropyl methacrylamide, N-n-propyl acrylamide, N-n-propyl methacrylamide, N-
cyclopropyl acrylamide, N-cyclopropyl methacrylamide, N-ethoxyethyl acrylamide, N-
ethoxyethyl methacrylamide, N-tetrahydrofurfuryl acrylamide, N-tetrahydrofurfuryl
methacrylamide, N-ethyl acrylamide, N-ethyl-N-methyl acrylamide, N,N-diethyl acrylamide,
N-methyl-N-n-propyl acrylamide, N-methyl-N-isopropyl acrylamide, N-acryloyl piperidine
and N-acryloyl pyrrolidine and acrylic monomers of formulas (1) to (6)



wherein, R1 represents a hydrogen atom or methyl group, R2 and R3 respectively and
independently represent a hydrogen atom or alkyl group having 1 to 3 carbon atoms, R4
represents an alkyl group having 1 to 2 carbon atoms, and n is 1 to 9 , and
a water-swellable clay mineral (b),
characterized in that a non-water-soluble polymerization initiator (d), is dispersed in
an aqueous medium (c), and,
the water-soluble organic monomer (a) is reacted in the resulting dispersion by
irradiating with an energy beam in the presence of the water-swellable clay mineral (b),
wherein non-water-soluble in (d) refers to the amount of the polymerization initiator
that dissolves in water being 0.5% by weight or less.
2. The production process of an organic/inorganic composite hydrogel as claimed in
claim 1, wherein dispersion of the non-water-soluble polymerization initiator (d) in the
aqueous medium (c) is prepared by dispersing a solution of polymerization initiator (d)
dissolved in a solvent (e) into the aqueous medium (c).
3. The production process of an organic/inorganic composite hydrogel as claimed in
claim 2, wherein the solvent (e) is an acrylic monomer (el) that dissolves the non-water-
soluble polymerization initiator (d) and has an HLB value of 8 or more, wherein said HLB
value is determined according to the Davis method.
4. The production process of an organic/inorganic composite hydrogel as claimed in
claim 2, wherein the solvent (e) is a water-soluble organic solvent (e2), of which 50 g or more
being able to be dissolved in 100 g of water, and said solvent being able to dissolve the non-
water-soluble polymerization initiator (d).

5. The production process of an organic/inorganic composite hydrogel as claimed in
claim 2, wherein weight ratio (d) / (e) of the non-water-soluble polymerization initiator (d) to
the solvent (e) in the solution in which the polymerization initiator (d) is dissolved in the
solvent (e) is within the range of 0.001 to 0.1.
6. The production process of an organic/inorganic composite hydrogel as claimed in
claim 2, wherein the dispersed amount of the solution in which the non-water-soluble
polymerization initiator (d) is dissolved in the solvent (e) is 5% by weight or less based on the
total weight of the water-soluble organic monomer (a), the water-swellable clay mineral (b),
the aqueous medium (c), the polymerization initiator (d) and the solvent (e) .
7. The production process of an organic/inorganic composite hydrogel as claimed in
claim 2, wherein the dispersed diameter when dispersing the solution in which the
polymerization initiator (d) is dissolved in the solvent (e) in the aqueous medium (c) is 1 µm
or less.
8. The production process of an organic/inorganic composite hydrogel as claimed in
claim 1, wherein the clay mineral (b) separates into 1 to 10 layers in the aqueous medium (c).
9. The production process of an organic/inorganic composite hydrogel as claimed in
claim 1, wherein the water-swellable clay mineral (b) is at least one type selected from the
group consisting of water-swellable hectorite, water-swellable montmorillonite, water-
swellable saponite and water-swellable synthetic mica.
10. The production process of an organic/inorganic composite hydrogel as claimed in
claim 1, wherein the weight ratio (b) / (a) of the water-swellable clay mineral (b) to the water-
soluble organic monomer (a) in the solution is within the range of 0.01 to 10.
11. The production process of an organic/inorganic composite hydrogel as claimed in
claim 1, wherein the irradiation with an energy beam is irradiation with an energy beam
through a mask having a pattern.
12. A production process of a dried organic/inorganic composite hydrogel comprising the
step of:

removing a solvent from an organic/inorganic composite hydrogel obtained
according to the production process of an organic/inorganic composite hydrogel according to
claim 1.


ABSTRACT

PROCESS FOR PRODUCTION OF ORGANIC-INORGANIC
HYBRID HYDROGEL
The present invention provides a production process of an
organic/inorganic composite hydrogel, which demonstrates
superior mechanical properties, by uniformly dispersing a clay
mineral in an organic polymer over a wide range of clay mineral
content, and a dried form thereof, to be produced easily in a
short period of time. The production process of an
organic/inorganic composite hydrogel of the present invention
comprises reacting a water-soluble organic monomer (a) in the
presence of a water-swellable clay mineral (b) by irradiating
with an energy beam in a solution in which a non-water-soluble
polymerization initiator (d) is dispersed in an aqueous medium
(c).

Documents:

02129-kolnp-2007-abstract.pdf

02129-kolnp-2007-assignment.pdf

02129-kolnp-2007-claims.pdf

02129-kolnp-2007-correspondence others 1.1.pdf

02129-kolnp-2007-correspondence others.pdf

02129-kolnp-2007-description complete.pdf

02129-kolnp-2007-form 1.pdf

02129-kolnp-2007-form 3.pdf

02129-kolnp-2007-form 5.pdf

02129-kolnp-2007-gpa.pdf

02129-kolnp-2007-international publication.pdf

02129-kolnp-2007-international search report.pdf

02129-kolnp-2007-priority document.pdf

2129-KOLNP-2007-(03-02-2012)-ABSTRACT.pdf

2129-KOLNP-2007-(03-02-2012)-AMANDED CLAIMS.pdf

2129-KOLNP-2007-(03-02-2012)-CORRESPONDENCE.pdf

2129-KOLNP-2007-(03-02-2012)-DESCRIPTION (COMPLETE).pdf

2129-KOLNP-2007-(03-02-2012)-FORM 1.pdf

2129-KOLNP-2007-(03-02-2012)-FORM 2.pdf

2129-KOLNP-2007-(03-02-2012)-FORM 3.pdf

2129-KOLNP-2007-(03-02-2012)-OTHERS.pdf

2129-KOLNP-2007-ABSTRACT.pdf

2129-KOLNP-2007-AMANDED CLAIMS.pdf

2129-KOLNP-2007-ASSIGNMENT.pdf

2129-KOLNP-2007-CORRESPONDENCE 1.1.pdf

2129-KOLNP-2007-CORRESPONDENCE-1.2.pdf

2129-KOLNP-2007-DESCRIPTION (COMPLETE).pdf

2129-KOLNP-2007-EXAMINATION REPORT REPLY RECIEVED.pdf

2129-KOLNP-2007-EXAMINATION REPORT.pdf

2129-KOLNP-2007-FORM 1.pdf

2129-KOLNP-2007-FORM 18-1.1.pdf

2129-kolnp-2007-form 18.pdf

2129-KOLNP-2007-FORM 2.pdf

2129-KOLNP-2007-FORM 3-1.2.pdf

2129-KOLNP-2007-FORM 3-3.1.pdf

2129-KOLNP-2007-FORM 3.1.pdf

2129-KOLNP-2007-FORM 5.pdf

2129-KOLNP-2007-GPA.pdf

2129-KOLNP-2007-GRANTED-ABSTRACT.pdf

2129-KOLNP-2007-GRANTED-CLAIMS.pdf

2129-KOLNP-2007-GRANTED-DESCRIPTION (COMPLETE).pdf

2129-KOLNP-2007-GRANTED-FORM 1.pdf

2129-KOLNP-2007-GRANTED-FORM 2.pdf

2129-KOLNP-2007-GRANTED-SPECIFICATION.pdf

2129-KOLNP-2007-OTHERS-1.2.pdf

2129-KOLNP-2007-OTHERS.pdf

2129-KOLNP-2007-PETITION UNDER RULE 137.pdf

2129-KOLNP-2007-REPLY TO EXAMINATION REPORT.pdf


Patent Number 253820
Indian Patent Application Number 2129/KOLNP/2007
PG Journal Number 35/2012
Publication Date 31-Aug-2012
Grant Date 28-Aug-2012
Date of Filing 11-Jun-2007
Name of Patentee KAWAMURA INSTITUTE OF CHEMICAL RESEARCH
Applicant Address 631, SAKADO, SAKURA-SHI, CHIBA-KEN
Inventors:
# Inventor's Name Inventor's Address
1 TAKADA, TETSUO C/O KAWAMURA INSTITUTE OF CHEMICAL RESEARCH, 631, SAKADO, SAKURA-SHI, CHIBA-KEN
2 TAKEHISA, TOORU C/O KAWAMURA INSTITUTE OF CHEMICAL RESEARCH, 631, SAKADO, SAKURA-SHI, CHIBA-KEN
3 HARAGUCHI, KAZUTOSHI C/O KAWAMURA INSTITUTE OF CHEMICAL RESEARCH, 631, SAKADO, SAKURA-SHI, CHIBA-KEN
PCT International Classification Number C08F 2/44,C08F 2/46
PCT International Application Number PCT/JP2005/022886
PCT International Filing date 2005-12-13
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2005-111914 2005-04-08 Japan
2 2004-361220 2004-12-14 Japan
3 2004-361221 2004-12-14 Japan