Title of Invention

NORMAL-PRESSURE CATION-DYEABLE POLYESTER, TEXTILE PRODUCT MADE FROM THE SAME, AND PRODUCTION METHOD FOR THE SAME

Abstract This invention relates to a normal-pressure cation-dyeable polyester comprising: ethylene terephthalate as a major recurring unit; 2.0 to 3.0 mol% of an isophthalic acid component having a metal sulfonate group based on the total of acid components present in the polyester; and not less than 1.5 wt% and less than 4.0 wt% of a polyalkylene glycol having an average molecular weight of 150 to 400 based on the weight of the polyester, wherein diethylene glycol is present in a proportion of 4.5 to 6.5 mol% based on the total of glycol components, wherein a terminal carboxyl group concentration is 20 to 30 equivalents/ton, wherein the polyester has a melt index of 1.8 to 3.0 g/10 min at 290°C.
Full Text DESCRIPTION
NORMAL-PRESSURE CATION-DYEABLE POLYESTER, TEXTILE
PRODUCT MADE FROM THE SAME, AND
PRODUCTION METHOD FOR THE SAME
TECHNICAL FIELD
The present invention relates to a normal-pressure
cation-dyeable polyester which is dyeable with a cationic
dye at a normal pressure, and to a continuous production
method therefor.
BACKGROUND ART
Polyethylene terephthalate fibers are generally
dyeable only with disperse dyes and azoic dyes and,
therefore, it is difficult to impart the polyethylene
terephthalate fibers with clear and deep colors. To
solve this problem, various polyester resin materials
have been proposed.
For example, Patent Document 1 proposes a
cation-dyeable polyester, which is obtained by
copolymerizing a polyester with 2 to 3 mol% of an
isophthalic acid component having a metal sulfonate
group.
Further, Patent Document 2 proposes
copolymerization with a polyethylene glycol having a


molecular weight of not smaller than 200 to provide a
dyeing facilitating effect. The polyethylene glycol has
a plasticizing effect, thereby suppressing a viscosity
increase which may otherwise occur due to the presence
of the sulfonate group. This makes it possible to
increase the polymerization degree of the polymer.
Further, copolymerization of a dicarboxylic acid
of a linear hydrocarbon such as adipic acid or sebacic
acid, or a glycol such as diethylene glycol, neopentyl
glycol, cyclohexanedimethanol or
1, 4-bis ((3-hydroxyethoxy) benzene with an isophthalic
acid having a sulfonate group is proposed to provide a
resin material to be employed for suppressing reduction
in light resistance and ensuring normal-pressure
dyeability (Patent Document 3).
On one hand, exemplary methods for industrially
producing polyesters include an ester interchange method
(hereinafter referred to as DMT method) employing
dimethyl terephthalate as described in Patent Document
3, and a direct polymerization method employing
terephthalic acid as described in Patent Document 4 . One
example of the direct polymerization method is a direct
continuous polymerization method in which oligomers are
extracted and introduced into a separate polymerization
tank after completion of esterification and polymerized


in batches as described in Patent Document 5. These
production methods are batch polymerization methods in
which polymerization reactions are caused in batches.
On the other hand, the inventors of the present
invention propose production of a normal-pressure
cation-dyeable polyester having a stable quality by
employing a direct continuous polymerization method as
described in Patent Document 6.
Patent Document 1: Japanese Examined Patent Publication
No. SH034 (1959)-10497
Patent Document 2 : Japanese Unexamined Patent Publication
No. SH063(1988)-256716
Patent Document 3: Japanese Unexamined Patent Publication
No. SH062 (1987)-89725
Patent Document 4: Japanese Examined Patent Publication
No. SH058(1983)-45971
Patent Document 5 : Japanese Unexamined Patent Publication
No. SH062(1987)-146921
Patent Document 6: Japanese Unexamined Patent Publication
No. 2002-284863
DISCLOSURE OF THE INVENTION
PROBLEMS TO BE SOLVED BY THE INVENTION
However, polyester fibers produced from the resin
of Patent Document 1 are dyeable only under
high-temperature and high-pressure conditions.


Therefore, the polyester fibers cannot be dyed after
having been coknitted or cowoven with natural fibers,
urethane fibers or the like. A resin obtained by
copolymerization with a great amount of the
sulfonate-group-containing isophthalic acid component
can be satisfactorily dyed at a normal pressure at a
temperature of about 100°C without a carrier. In this
case, however, the viscosity increasing effect due to
the presence of the sulfonate group increases only the
melt viscosity but does not increase the polymerization
degree of the polymer. This presents problems such that
a spinning filter pressure is increased at a higher rate
and filament breakage frequently occurs, thereby
deteriorating the spinnability.
The use of the polyester obtained by the
copolymerization with the polyethylene glycol as
described in Patent Document 2 suppresses the viscosity
increasing effect attributable to the presence of the
sulfonate group and increases the polymerization degree
of the polyester, but the polyester has poorer light
resistance.
The use of the polyesters described in Patent
Documents 3 to 5 permits normal pressure dyeing, and
improves the light resistance. However, these
polyesters are generally produced in batches and,


therefore, significantly differ in physical properties
between batches. Further, the spinnability is
significantly deteriorated, and the resulting filaments
are poorer in quality.
The normal-pressure cation-dyeable polyester
described in Patent Document 6 has uniform physical
properties, but dark-color light fastness is still
unsatisfactory.
It is therefore an object of the present invention
to solve the problems associated with the prior art to
provide a normal-pressure cation-dyeable polyester which
is stable in quality and excellent in dark- and pale-color
light fastness when used for a textile product, and to
provide a production method for the polyester.
MEANS FOR SOLVING THE PROBLEMS
According to a first aspect of the present
invention, there is provided a normal-pressure
cation-dyeable polyester which comprises: ethylene
terephthalate as a major recurring unit; 2.0 to 3.0 moll
of an isophthalic acid component having a metal sulfonate
group based on the total of acid components present in
the polyester; and not less than 1.5 wt% and less than
4.0 wt% of a polyalkylene glycol having an average
molecular weight of 150 to 600 based on the weight of
the polyester; wherein diethylene glycol is present in


a proportion of 4.5 to 6.5 mol% based on the total of
glycol components; wherein a terminal carboxyl group
concentration is 20 to 30 equivalents/ton.
According to a second aspect, the normal-pressure
cation-dyeable polyester has a ratio of a maximum value
[η] max to a minimum value [η]min of an intrinsic viscosity
satisfying 1.0 ≤ [η] max/ [η] min ≤1.02. According to a
third aspect, the normal-pressure cation-dyeable
polyester has a melt index of 1.8 to 3.0 g/10 min at 290°C.
According to a fifth aspect of the present
invention, there is provided a continuous production
method for continuously producing a normal-pressure
cation-dyeable polyester through a direct esterification
reaction and polycondensation by employing terephthalic
acid, ethylene glycol, an isophthalic acid component
having a metal sulfonate group and a polyalkylene glycol
as ingredients, the method comprising the steps of:
slurrying dicarboxylic acid components and the ethylene
glycol, adjusting pH of the resulting slurry to 4.5 to
5.5, and continuously supplying the slurry into a first
esterification tank; controlling an in-tank molar ratio
of the ethylene glycol to the dicarboxylic acid components
including the terephthalic acid and the
metal-sulfonate-group-containing isophthalic acid to
0.9 to 1.1 toprovide an oligomer having an esterification

ratioof 80 to 90%, and continuously supplying the oligomer
into a second esterification tank; adding the
polyalkylene glycol, and controlling the in-tank molar
ratio to 1.1 to 1.2 to cause an esterif ication reaction;
and sequentially introducing the resulting product into
a polymerization tank, and causing a polymerization
reaction at a reduced pressure.
According to a sixth aspect, a series of lot changes
is continuously made without interruption of the steps
in the normal-pressure cation-dyeable polyester
continuous production method.
EFFECTS OF THE INVENTION
The inventive normal-pressure cation-dyeable
polyester is stable in quality, and can be efficiently
produced at lower costs. The inventive polyester can
be easily dyed with a cationic dye at a normal pressure
at a temperature of not higher than 100°C without a carrier,
and is excellent in dark- and pale-color light fastness.
The inventive polyester can be melt-spun and post-treated
under conditions close to those employed for an ordinary
polyethylene terephthalate with excellent operability.
Even if fibers of the inventive polyester are dyed after
having been coknitted or cowoven with natural fibers,
urethane fibers or the like for swimming wear and underwear
applications, high quality textile products can be

provided without degradation of the natural fibers and
the urethane fibers.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic diagram showing an exemplary
direct continuous polymerization method suitable for
production of an inventive normal-pressure
cation-dyeable polyester.
DESCRIPTION OF REFERENCE CHARACTERS
1
2
3
4
5
Slurrying tank
First esterification tank
Second esterification tank
Initial polymerization tank
Final polymerization tank
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will
hereinafter be described in detail. ^
The present invention provides a normal-pressure
cation-dyeable polyester having ethylene terephthalate
as a major recurring unit.
The inventive polyester contains 2.0 to 3.0 mol%
of an isophthalic acid component having a metal sulfonate
group (hereinafter referred to as SIP component) based
on the total of acid components present in the polyester.
If the content of the SIP component is too low, it is
impossible to provide sufficient normal-pressure


cation-dyeability. If the content is too high, a
viscosity increase and gelation are liable to occur due
tochargesoftheSIP component in a melt-spinning process,
thereby remarkably reducing the operability.
The SIP component may be addedby copolymerization,
mixing or any other method, but is preferably
copolymerized for uniform dyeing of fibers.
Where the SIP component is copolymerized, the
content is preferably in the aforementioned range for
sufficient normal-pressure cation-dyeability, for
prevention of the viscosity increase and the gelation
attributable to the charges of the SIP component in the
melt-spinning process, and for the operability.
Examples of the SIP component according to the
present invention include dimethyl
5-metal-sulfoisophthalate (hereinafter referred to as
SIPM) and a compound obtained by esterification of two
methyl groups thereof with ethylene glycol (hereinafter
referred to as SIPE). If a great amount of the SIPM is
supplied into a slurry tank,, the physical properties of
the resulting slurry are deteriorated. Therefore, the
SIPE is more preferable. Examples of a metal contained
inthe SIP component include sodium, potassium and lithium,
among which sodium is most preferable.
The inventive polyester contains a polyalkylene


glycol having an average molecular weight of 150 to 600,
more preferably 200 to 400.
If the molecular weight is less than 150, the
resulting polyester is liable to experience a hydrolysis
reaction in the melt-spinning process and hence have a
lower melting point and a lower glass transition
temperature. Therefore, pellets of the polyester are
liable to be melt-bonded to each other, and chalking is
liable to occur in a preliminary filament twisting process
If the molecular weight is greater than 600, the light
fastness and the heat resistance of the polymer are
deteriorated.
Thepolyalkylene glycol is represented by a general
formula of HO(CnH2nO)mH (wherein n and m are positive
integers), and polyethylene glycol defined by n=2 in the
formula (hereinafter referred to as PEG) is generally
used and most preferable.
Here, the polyalkylene glycol may be added by
copolymerization, blending in a polymerization step,
blending in a kneading step or any other method, but is
preferably copolymerized for a stable post-treatment
process .
The content of the polyalkylene glycol should be
not less than 1.5 wt% and less than 4.0 wt%, preferably
2 to 3 wt%, based on the weight of the polyester. If

the content is less than 1.5 wt%, the normal-pressure
cation-dyeability is unsatisfactory, and the
spinnability is liable to be deteriorated because the
viscosity increase and the gelation due to the charges
of the SIP component cannot be suppressed. On the other
hand, if the content is not less than 4, wt%, the
normal-pressure cation-dyeability is improved, but the
heat resistance of the polyester is reduced to deteriorate
the color tone of the polyester. Further, the glass
transition temperature is reduced, whereby the pellets
of the polyester are liable to be melt-bonded to each
other. Where the polyalkylene glycol is copolymerized,
the content is preferably in the aforementioned range.
The inventive polyester should contain 4.5 to 6.5
mol%, preferably 5 to 6%, of diethylene glycol—7
(hereinafter referred to as DEG) based on the total of
glycol components present in the polyester. Most of the
DEG is produced as a by-product during an esterification
reaction. If the content of the DEG is less than 4.5
mol%, the normal-pressure cation-dyeability is
deteriorated. If the content is greater than 6.5 mol%,
the heat resistance and the oxidation resistance of the
polyester and the color tone of the polyester are
deteriorated, and the melt-spinnability is significantly
deteriorated.


Further, the terminal carboxyl group

concentration of the inventive polyester is 20 to 30
equivalents/ton. In a system in which several types of
modifiers are copolymerized as in the case of the
normal-pressure cation-dyeable polyester, the heat
resistance is generally deteriorated. If the terminal
carboxyl group concentration falls within this range,
the color tone of the polyester and the heat resistance
in the spinning process and the post-treatment process
are satisfactory.
The ratio of a maximum value [η]max to a minimum
value [η]min of the intrinsic viscosity of the inventive
polyester is preferably 1.0 ≤ [η] max/ [η] min ≤ 1.02, more
preferably between 1. 0 and 1. 01. If [η] max/[η] min falls
within the aforementioned range, the spinnability and
the dyeing uniformity are improved.
The melt index (MI) of the inventive polyester as
measured when the polyester is melt-extruded at 290°C is
preferably set to 1.8 to 3.0 g/10 min. If the melt index
falls within this range, more excellent spinnability is
ensured during spinning of high multi-filaments each
having a smaller single filament fineness and profile
filaments. Further, a normal-pressure cation-dyeable
yarn can be produced, which is highly strong and has
stretchability suitable for weaving.


The inventive polyester may contain modifiers such
as a light resistant agent, a heat resistant agent and
a delustering agent for improving the physical properties
thereof.
The inventive normal-pressure cation-dyeable
polyester described above in detail contains the SIP
component, the polyalkylene glycol component and the DEG
component in proper proportions, and can be stably spun
into filaments in the melt-spinning process. Therefore,
the filaments are uniformly dyeable with a cationic dye,
and excellent in dark- and pale-color light fastness.
In the spinning of the polyester, the spinning
filter pressure increasing rate is lower, and the
spinnability is excellent. Further, the polyester is
resistant to thermal aging. Therefore, where the
polyester is used as a spinning material, filaments can
be produced as having a stable quality at a higher spinning
productivity.
Filaments produced by employing the polyester as
a spinning material and dyed with a cationic dye at a
normal pressure are excellent in dark- and pale-color
light fastness and less expensive. Since the filaments
can be dyed at a normal pressure, a fabric produced by
employing the filaments in combination with less
heat-resistant fibers such as natural fibers or urethane


fibers can be dyed. Therefore, a high quality textile
product can be efficiently produced.
Next, a method suitable for the production of the
inventive polyester will be described in detail with
reference to the drawing.
Fig. 1 is a schematic diagram illustrating a
process according to one embodiment of the present
invention.
First, terephthalic acid and a glycol are slurried
in a slurrying tank 1, and then a
metal-sulfonate-containing isophthalic acid compound
(a) containing an SIP component is supplied to the tank
1 to provide a slurry.
Thereafter, the slurry is continuously supplied
into a first esterification tank 2 for an esterification
reaction to provide oligomers, which are sequentially
supplied into a second esterification tank 3.
Subsequently, the oligomers are continuously supplied
into an initial polymerization tank 4 and then into a
final polymerization tank 5, whereby the oligomers
continuously experience a polymerization reaction to a
predetermined polymerization degree in vacuum.
As described above, the SIP component is preferably
added to the slurry containing terephthalic acid and
ethylene glycol as major components in the slurrying tank


1. The addition of the SIP component in the slurrying
tank 1 provides a so-called random copolymer in which
the SIP component is evenly distributed in a molecule
chain of the polyester, thereby permitting uniform dying
with a basic dye. Further, where the normal-pressure
cation-dyeable polyester is spun, the filter pressure
increase is suppressed which may otherwise occur due to
gelation caused by the SIP component. Therefore, the
cycle of the replacement of a spinneret can be prolonged.
In the present invention, the production is
preferably achieved by direct continuous polymerization
as described above. The continuous polymerization
method makes it easy to add the SIP component in the
aforesaid timing.
Prior-art methods for producing cation-dyeable
polyesters as in the present invention are roughly
classified into two categories: (1) the DMT method
described in Patent Document 3; and (2) the direct
polymerization method described in Patent Document 4.
The former method is problematic in recovery and handling
of methanol resulting from ester interchange between
dimethyl terephthalate and ethylene glycol, and requires
a greater amount of ethylene glycol for the reaction.
Therefore, the latter direct polymerization method is
predominant in recent years.


In the case of the DMT method, a preliminarily
adding method in which the SIP component and DMT are
simultaneously added may be employed, thereby permitting
uniform reaction of the SIP component. However, the DMT
method is not suitable for industrial production because
of the aforesaid reasons and poorer color tone of the
resulting polyester.
The direct polymerization method is suitable for
industrial production. In the direct esterification
method, an esterification reaction is generally allowed
to proceed while the slurry is additionally supplied to
the esterification tank in which a seed prepolymer is
present. In this case, if the SIP component is added
in the slurrying tank, the amount of the DEG produced
as a by-product is significantly increased due to the
acidification effect of the SIP component to reach a level
not less than 10 moll based on the total of the acid
components present in the slurrying tank, thereby
deteriorating the heat resistance of the polyester. In
the direct polymerization method, therefore, it is a
common practice to supply the SIP component into the
polymerization tank immediately before the start of the
polycondensation reaction after the prepolymer obtained
through the esterification reaction is transferred into
the polymerization tank.


In the present invention, on the other hand, the
direct continuous polymerization method in which the SIP
component is supplied into the slurrying tank 1 is
preferably employed out of the direct polymerization
method. The inventive method can easily control the
amount of the DEG as will be described later.
When the SIP component is supplied into the
slurrying tank 1, the amount of the DEG produced as a
by-product is significantly increased. Therefore, the
pH of the slurry is preferably adjusted to 4.5 to 5.5.
More specifically, an alkali such as sodium acetate
trihydrate, manganese acetate tetrahydrate, sodium
hydroxide, potassium hydroxide or tetraethylammonium
hydroxide is properly added for the adjustment.
If -the pH of the slurry is lower than 4.5, an
increased amount of the DEG produced as a by-product is
liable to deteriorate the color tone of the polyester
and reduce the melting point and the glass transition
temperature of the polyester to deteriorate the heat
resistance of the polyester. If the pH is adjusted to
higherthan5.5, the alkali is added in an increased amount,
and acts as foreign matter to deteriorate the
spinnability.
Further, the in-tank molar ratio of the ethylene
glycol to dicarboxylic acid components in the first


esterification tank 2 is preferably controlled to 0.9
to 1.1. If the molar ratio falls within this range, the
amount of the DEG produced as a by-product can be easily
set within the range specified in the present invention
during the esterification reaction.
The internal pressure of the first esterification
tank 2 is not particularly limited, but is preferably
set at a gage pressure of 68 . 7 to 147 .1 kPa, morepreferably
88.3 to 117.7 kPa. If the internal pressure falls within
this range, water generated by the reaction with the
ethylene glycol can be stably separated, so that the amount
of the DEG produced as a by-product can be easily set
within the range specified in the present invention.
In the present invention, the oligomers to be
continuously supplied into the second esterification tank
3 in which the polyalkylene glycol is added preferably
has an esterification ratio of 80 to 90%, more preferably
82 to 87%, in the first esterification tank 2 in terms
of the heat resistance and the spinnability of the
polyester.
That is, if the esterification ratio is less than
80%, a thermal load in the second esterification tank
3 in which the reaction occurs at a normal pressure is
increased. Therefore, the reaction system is not
stabilized, and the terminal carboxyl group concentration


of the polyester to be described later falls outside the
concentration range specified for the inventive polyester,
thereby deteriorating the heat resistance of the
polyester. If the esterification ratio is greater than
90%, the polyalkylene glycol is locally present in the
polyester molecule chain during the reaction, or is not
completely copolymerized but dispersed in a blended state.
Therefore, the heat resistance and hence the spinnability
of the polyester are liable to be deteriorated, and
chalking is liable to occur due to bleeding of the
polyalkylene glycol when the resulting polyester
filaments are post-treated.
In order to control the terminal carboxyl group
concentration within the range specified in the present
invention, the in-tank molar ratio of the ethylene glycol
to the dicarboxylic acid components in the second
esterification tank 3 is preferably limited to 1.1 to
1.2, more preferably 1.12 to 1.17.
Ifthe molar ratio is less than 1. 1, a smaller amount
of the ethylene glycol is present in the polymerization
reaction, so that the amount of the terminal carboxyl
group is liable to fall outside the range specified in
the present invention. If the molar ratio is greater
than 1.2, the amount of the terminal .carboxyl group is
liable to be lower than the range specified in the present


invention. Further, the amount of ethylene glycol
generated in the polymerization process is increased.
Therefore, the aforementioned range is preferred from
both an economic viewpoint and an environmental
viewpoint.
When the inventive polyester is produced by the
direct continuous polymerization method, the intrinsic
viscosity ratio of the inventive polyester can be easily
controlled by: (1) limiting pH in the slurrying tank 1 ;
(2) controlling the molar ratio and the internal pressure
in the first esterification tank; (3) limiting the molar
ratio in the second esterification tank; (4) setting the
SIP component adding position and the polyalkylene glycol
adding position at the aforementioned positions; and (5)
setting the temperature of the polyester polymerization
reaction at not higher than 280°C.
Modifiers such as a light resistant agent, a heat
resistant agent and a delustering agent may be added to
the inventive normal-pressure cation-dyeable polyester
for improvement of the physical properties. These
additives may be added at any stage of the production
process, but are preferably added in the form of an
ethylene glycol dispersion in the slurring step for
prevention of coagulation.
The direct continuous polymerization method is


employed for production of the inventive normal-pressure
cation-dyeable polyester. In this case, it is preferred
in terms of costs that a previous production lot is
continuously changed to a production lot for the
normal-pressure cation-dyeable polyester and, after the
production of the normal-pressure cation-dyeable
polyester, the production lot is continuously changed
to the next production lot.
Where the process is once stopped, the amount of
waste to be discharged is increased, and costs and labor
are required for cleaning the polymerization tanks.
Therefore, where the lot changes are continuously made,
process variations in the system are preferably minimized.
To this end, the concentrations of the
metal-sulfonate-containing isophthalic acid and the
polyalkylene glycol are controlled, and the reaction
temperature, the pressure and the in-system retention
time are controlled.
EXAMPLES
The present invention will hereinafter be
described in greater detail by way of examples thereof.
In the following examples, values were measured by the
following methods.
(1) Intrinsic Viscosity [η]
Specimens for measurement of the intrinsic


viscosity [η] of polymer chips were sampled in the
following manner. Polymer chips produced by the
continuous polymerization method were sampled at proper
time intervals, and employed as samples. Polymer chips
produced by a batch polymerization method were sampled
for each batch after the start of extrusion of the polymer,
immediately before completion of the extrusion, and
during the extrusion, and employed as samples. The
intrinsic viscosity of each of the samples was measured
in a solvent mixture of phenol/tetrachloroethane = 6/4
(weight ratio) at 20°C by the Uberode method. The number
of samples for each case was five. The highest one of
the intrinsic viscosities of the five samples was defined
as [r|]max, and the lowest one of the intrinsic viscosities
of the five samples was defined as [r|]min. Then,
[η] max/ [η] min was calculated from the measurement results ,
and employed as an index of the intrinsic viscosity
unevenness of the polymer.
(2) Average Molecular Weight of Polyalkylene
Glycol
The hydroxyl value of a polyalkylene glycol was
measured by a pyridine-acetic anhydride method specified
by JIS K-0070, and the average molecular weight of the
polyalkylene glycol was calculated by an ordinary method.
(3) Diethylene Glycol (DEG) Amount


Polyester pellets were pulverized, saponified in
a potassium hydroxide-methanolsolution, hydrolyzedwith
pure water, neutralized with terephthalic acid, and
analyzed by gas chromatography, and the content of
diethylene glycol was determined by an internal standard
method. Then, the mole percentage of the DEG in the
polymer was calculated from the following expression:
DEG (moll) = 100 x DEG mole number/(DEG mole number
+ EG mole number)
(4) Terminal Carboxyl Group Concentration (COOH)
Polyester pellets were pulverized and dissolved
in hot benzyl alcohol. After addition of chloroform,
the terminal carboxyl group concentration was determined
by titration of an acid component with a 1/50 N potassium
hydroxide-benzyl alcohol solution, and expressed in
equivalent per ton of the polyester.
(5) Melt Index (MI)
Polyester pellets were dried in vacuum at 150°C
for five hours to a moisture content of 20 to 30 ppm.
Then, the weight of the polyester melt and extruded from
a 0.5-mm measured with the use of a melt indexer produced by Toyo
Seiki Kogyo Co . , Ltd., and converted to an extrusion weight
per 10 minutes.
(6) Color Tone of Polymer


The color of polyester pellets was measured by a
color measurement colorimeter produced by Nippon Denshoku
Kogyo Co., Ltd., and a value Lab was calculated.
Polyester pellets having a value b less than 6 were
symbolized by O, and polyester pellets having a value
not less than 6 were symbolized by x.
(7) Spinnability
The resulting normal-pressure cation-dyeable
polyester was spun into 44 dtex/36f filaments by a direct
spin-drawing method, and the spinnability was rated as
O, A and x in descending order based on the spinning
filter pressure increase rate and the number of times
of filament breakage.
(8) Dyeability with Cationic Dye
Dyeability with a cationic dye was determined by
dyeing a polyester in a dye solution containing 3.0 %owf
of Kayacryl Blue GSL-ED (Nippon Kayaku Co., Ltd.) and
0.2 g/1 of acetic acid at a bath ratio of 1:50 at a boiling
point (98°C) at a normal pressure for 60 minutes, and the
absorbance of the dye solution was measured before and
after the dyeing. Then, an exhaustion dyeing percentage
(%) was calculated from the following expression. A
polyester having an exhaustion dyeing percentage of not
less than 90% was symbolized by ©, a polyester having
an exhaustion dyeing percentage of not less than 80% and


less than 90% was symbolized by O, a polyester having
an exhaustion dyeing percentage of not less than 70% and
less than 80% was symbolized by A, and a polyester having
an exhaustion dyeing percentage of less than 70% was
symbolized by x.
Exhaustion dyeing percentage (%) =100 x ( Pre-dying Absorbance
- Post-dyeing Absorbance)/Pre-dyeing Absorbance
(9) Light Fastness
Tubular knitted samples were prepared from a 44
dtex/36f normal-pressure cation-dyeable yarn, dyed in
dye solutions respectively containing Kayacryl Blue
GSL-ED (Nippon Kayaku Co., Ltd.) in concentrations of
0.2 %owf and 1.0 %owf at a bath ratio of 1:30 at 98°C at
a normal pressure for 30 minutes , rinsed with water, dried,
and heat-set at 160°C for 1 minute. Then, the samples
were respectively subjected to a light fastness test in
a 63°C environment for 20 hours and for 40 hours with the
use of a fade meter, and compared with a blank sample
for comparison of fading states. For evaluation, a
sample having no difference from the blank sample after
the 20-hour light fastness test was rated as not lower
than the third grade, and a sample having no difference
from the blank sample after the 40-hour light fastness
test was rated as not lower than the fourth grade. A
sample rated as lower than the third grade was symbolized


by x, a sample rated as not lower than the third grade
and lower than the fourth grade was symbolized by O, and
a sample rated as not lower than the fourth grade was
symbolized by ©.
(10) Breaking Strength and Breaking Extension
The breaking strength and the breaking extension
were determined at a constant stretching rate of 20 cm/min
by employing a 20-cm long sample in conformity with JIS
L-1013 by means of an autograph tensile tester AGS-1KNG
produced by Shimadzu Corporation.
(11) Evaluation of Filament Breaking Strength
A sample having a breaking strength measurement
value of not less than 3.0 cN/dtex as determined by the
test specified by the item (10) was symbolized by O, and
a sample having a breaking strength measurement value
of less than 3.0 cN/dtex was symbolized by A.
(12) High Multi-Filament Spinnability
The resulting normal-pressure cation-dyeable
polyester was spun into 33 dtex/36f filaments by a direct
spin-drawing method, and the spinnability was rated as
O, A and x in descending order based on the spinning
filter pressure increase rate and the number of times
of filament breakage.
(13) Profile Filament Spinnability
The resulting normal-pressure cation-dyeable


polyester was spun into 44 dtex/36f triangle profile
filaments by a direct spin-drawing method, and the
spinnability was rated as O, A and x in descending order
based on the spinning filter pressure increase rate and
the number of times of filament breakage.
[Example 1]
Terephthalic acid, ethylene glycol and SIPE (2.5
mol% based on the total of acid components) were supplied
into the slurrying tank 1, and 320 ppm of titanium dioxide
as a delustering agent, 45 ppm of trimethyl phosphate
and 800 ppm of sodium acetate trihydrate based on the
amount of a polymer were added to the resulting slurry.
After the pH of the resulting slurry was adjusted to 5.0,
the slurry was continuously supplied into the first
esterification tank 2, and subjected to a pressurized
reaction at a reaction temperature of 270°C at a gage
pressure of 88.2 kPa with the molar ratio of the ethylene
glycol to dicarboxylic acid components being adjusted
to 1.0 to provide a prepolymer having an esterification
ratio of 85%. Then, the prepolymer was continuously
supplied into the second esterification tank 3, and 3
wt% of polyethylene glycol having a molecular weight of
200 based on the amount of the polymer was continuously
added to the prepolymer. Then, 0.2 wt% of a hindered
phenol antioxidant IRGANOX (registered trade mark) 245

' '
(produced by Ciba Geigy Corporation) and 270 ppm of
antimony trioxide dissolved in ethylene glycol were added
to the prepolymer with the molar ratio of the ethylene
glycol being adjusted to 1.13 in the second esterification
tank, and the resulting mixture was subjected to an
esterification reaction at a normal pressure.
Thereafter, the resulting product was continuously
transferred to the initial polymerization tank 4 and then
to the final polymerization tank 5, and continuously
subjected to a polymerization reaction at a reaction
temperature of 280°C. Thus, a polyester polymer having
a melt viscosity of 250 Pa-s as measured at 280°C by a
capillary viscometer was provided. A retention time from
the esterification to the completion of the
polymerization reactionwas 5. 6 hours, andtheproduction
was carried out at a production rate of 38 ton/day. The
polyester polymer had an intrinsic viscosity ratio
[η]max/[η]min of 1.005 and a melt index value of 2.4 g/10
min at 290°C.
Pellets were prepared from the polyester polymer,
dried, and 44 dtex/36f normal-pressure cation-dyeable
filaments were prepared from the pellets by a direct
spin-drawing method. A tubular knitted fabric was
prepared from the normal-pressure cation-dyeable
filaments, and dyed with a cationic dye at 98°C in the


aforementioned manner. The exhaustion dyeing
percentage and the light fastness of the tubular knitted
fabric were measured. The normal-pressure
cation-dyeable filaments were satisfactory with a
breaking strength of 3. 20 cN/dt ex and a breaking extension
of 34.3%. The characteristic properties are shown in
Table 1.
[Examples 2 to 14 and Comparative Examples 1 to 10]
Polyesters were prepared through the
polycondensation reaction in substantially the same
manner as in Example 1, except that the amount of the
added SIPE, the amount and the molecular weight of the
added polyalkylene glycol, the amount of the DEG and the

amount of the terminal carboxyl group were changed as
shown in Tables 1 and 2. The characteristic properties
of the polyesters thus prepared are shown in Tables 1
and 2.






[Examples 15 to 17]
Polyesters were prepared through the
polycondensation reaction in substantially the same
manner as in Example 1, except that the intrinsic viscosity
ratios thereof were adjusted to values shown in Table
3. The results of the spinnability evaluation of the
polyesters thus prepared are shown in Table 3.
[Example 18]
A slurry of terephthalic acid and ethylene glycol
was prepared, and transferred to an esterification tank,
in which an esterification reaction was allowed to proceed
to provide a prepolymer having an esterification ratio
of 96.5%. After the prepolymer was transferred to a
polymerization tank, 2.5 mol% of SIPE based on the total
ofdicarboxylicacid components and 3 wt% of apolyethylene
glycol having a molecular weight of 200 based on the weight
of a polyester were added to the prepolymer, and a
polyester was prepared through a polycondensation
reaction. The intrinsic viscosity ratio and the result
of the spinnability evaluation of the polyester thus
prepared are shown in Table 3.


[Examples 19 to 22]
Polyesters each having a melt viscosity as shown
in the following Table 4 as measured at 280°C by a capillary
viscometer were prepared through a polycondensation
reaction by a direct continuous polymerization method
as in Example 1. Then, normal-pressure cation-dyeable
filaments were prepared from the respective polyesters
thus prepared in the same manner as in Example 1. The
MI, the spinnability, the high multi-filament
spinnability and the profile filament spinnability of
each of the polyesters and the breaking strength and the
filament breaking strength evaluation of each of the
normal-pressure cation-dyeable filaments are shown in
Table 4.


Example 19 had a higher breaking strength of 3.4
cN/dtex, but was poorer in spinnability than Example 1.
Examples 20 and 21 had higher breaking strengths of 3.3
cN/dtex and 3 .1 cN/dtex, respectively, and were excellent
in spinnability. Example 22 had a lower breaking
strength of 2 . 5 cN/dtex, and a fabric produced from the
filaments of Example 22 was poorer in friction strength
and more susceptible to pilling than Example 1.
Examples 19 to 22 were satisfactory in exhaustion
dyeing percentage and light fastness which were measured
in the same manner as in Example 1.
INDUSTRIAL APPLICABILITY
The inventive normal-pressure cation-dyeable
polyester is stable in quality, and can be efficiently
produced at lower costs. The polyester can be easily

dyed with a cationic dye at a normal pressure at a
temperature not higher than 100°C without a carrier, and
is excellent in dark- and pale-color light fastness. The
polyester can be melt-spun and post-treated with
excellent operability under conditions close to those
employed for an ordinary polyethylene terephthalate.
Therefore, even if fibers of the inventive polyester are
dyed after having been coknitted or cowoven with natural
fibers, urethane fibers or the like for swimming wear
and underwear applications , high quality textile products
can be provided without deterioration of the natural
fibers and the urethane fibers.

WE CAIM:
1. A normal-pressure cation-dyeable polyester comprising:
ethylene terephthalate as a major recurring unit;
2.0 to 3.0 mol% of an isophthalic acid component having a metal
sulfonate group based on the total of acid components present in the
polyester; and
not less than 1.5 wt% and less than 4.0 wt% of a polyalkylene glycol
having an average molecular weight of 150 to 400 based on the weight
of the polyester,
wherein diethylene glycol is present in a proportion of 4.5 to 6.5 mol%
based on the total of glycol components,
wherein a terminal carboxyl group concentration is 20 to 30
equivalents/ ton,
wherein the polyester has a melt index of 1.8 to 3.0 g/10 min at
290°C.
2. A normal-pressure cation-dyeable polyester as set forth in claim 1,
which has a ratio of a maximum value [η] max to a minimum value [η]
min of an intrinsic viscosity satisfying 1.0 ≤ [η]max/[η]min ≤ 1.02.
3. A textile product comprising a normal-pressure cation-dyeable
polyester as recited in claim 1 or 2.
4. A continuous production method for continuously producing a
normal-pressure cation-dyeable polyester as claimed in claim 1
through a direct esterification reaction and polycondensation by
employing terephthalic acid, ethylene glycol, an isophthalic acid

component having a metal sulfonate group and a polyalkylene glycol
as ingredients, the method comprising the steps of:
slurrying dicarboxylic acid components including the terephthalic
acid and the metal-sulfonate-group-containing isophthalic acid and
the ethylene glycol, adjusting pH of the resulting slurry to 4.5 to 5.5,
and continuously supplying the slurry into a first esterification tank;
controlling an in-tank molar ratio of the ethylene glycol to the
dicarboxylic acid components to 0.9 to 1.1 to provide an oligomer
having an esterification ratio of 80 to 90%, and continuously
supplying the oligomer into a second esterification tank;
continuously adding the polyalkylene glycol, and controlling the in-
tank molar ratio to 1.1 to 1.2 to cause an esterification reaction; and
sequentially introducing the resulting product into a polymerization
tank, and causing a polymerization reaction at a reduced pressure.
5. A normal-pressure cation-dyeable polyester continuous production
method as set forth in claim 4, wherein a series of lot changes is
continuously made without interruption of the steps.


This invention relates to a normal-pressure cation-dyeable polyester
comprising: ethylene terephthalate as a major recurring unit; 2.0 to
3.0 mol% of an isophthalic acid component having a metal sulfonate
group based on the total of acid components present in the polyester;
and not less than 1.5 wt% and less than 4.0 wt% of a polyalkylene
glycol having an average molecular weight of 150 to 400 based on the
weight of the polyester, wherein diethylene glycol is present in a
proportion of 4.5 to 6.5 mol% based on the total of glycol components,
wherein a terminal carboxyl group concentration is 20 to 30
equivalents/ton, wherein the polyester has a melt index of 1.8 to 3.0
g/10 min at 290°C.

Documents:

03696-kolnp-2007-abstract.pdf

03696-kolnp-2007-claims.pdf

03696-kolnp-2007-correspondence others 1.1.pdf

03696-kolnp-2007-correspondence others 1.2.pdf

03696-kolnp-2007-correspondence others.pdf

03696-kolnp-2007-description complete.pdf

03696-kolnp-2007-drawings.pdf

03696-kolnp-2007-form 1.pdf

03696-kolnp-2007-form 2.pdf

03696-kolnp-2007-form 3.pdf

03696-kolnp-2007-form 5.pdf

03696-kolnp-2007-gpa.pdf

03696-kolnp-2007-international exm report.pdf

03696-kolnp-2007-international publication.pdf

03696-kolnp-2007-international search report 1.1.pdf

03696-kolnp-2007-international search report.pdf

03696-kolnp-2007-pct request form.pdf

03696-kolnp-2007-translated copy of priority document.pdf

3696-KOLNP-2007-ABSTRACT.pdf

3696-KOLNP-2007-AMANDED CLAIMS.pdf

3696-KOLNP-2007-CORRESPONDENCE OTHERS 1.3.pdf

3696-KOLNP-2007-CORRESPONDENCE-1.4.pdf

3696-kolnp-2007-correspondence.pdf

3696-KOLNP-2007-DESCRIPTION (COMPLETE).pdf

3696-KOLNP-2007-ENGLISH TRANSLATION.pdf

3696-kolnp-2007-examination report.pdf

3696-KOLNP-2007-FORM 1.pdf

3696-kolnp-2007-form 18.1.pdf

3696-KOLNP-2007-FORM 18.pdf

3696-KOLNP-2007-FORM 2.pdf

3696-kolnp-2007-form 26.pdf

3696-kolnp-2007-form 3.1.pdf

3696-KOLNP-2007-FORM 3.pdf

3696-kolnp-2007-form 5.pdf

3696-KOLNP-2007-FORM-27.pdf

3696-kolnp-2007-granted-abstract.pdf

3696-kolnp-2007-granted-claims.pdf

3696-kolnp-2007-granted-description (complete).pdf

3696-kolnp-2007-granted-drawings.pdf

3696-kolnp-2007-granted-form 1.pdf

3696-kolnp-2007-granted-form 2.pdf

3696-kolnp-2007-granted-specification.pdf

3696-KOLNP-2007-OTHERS PCT FORM.pdf

3696-KOLNP-2007-OTHERS.pdf

3696-kolnp-2007-others1.1.pdf

3696-KOLNP-2007-PETITION UNDER RULE 137-1.1.pdf

3696-KOLNP-2007-PETITION UNDER SECTION 8(1) WITH RULE 12.pdf

3696-KOLNP-2007-REPLY TO EXAMINATION REPORT.pdf

3696-kolnp-2007-reply to examination report1.1.pdf

3696-kolnp-2007-translated copy of priority document.pdf

abstract-03696-kolnp-2007.jpg


Patent Number 247829
Indian Patent Application Number 3696/KOLNP/2007
PG Journal Number 21/2011
Publication Date 27-May-2011
Grant Date 25-May-2011
Date of Filing 01-Oct-2007
Name of Patentee KB SEIREN, LTD.
Applicant Address 6-1-1, SHIMOKOUBATA-CHO, SABAC-CITY, FUKUI
Inventors:
# Inventor's Name Inventor's Address
1 KEITA KATSUMA 17-5-B-201, MIZUOCHI-CHO 4-CHOME, SABAE-SHI, FUKUI 916-0022
PCT International Classification Number C08G 63/688
PCT International Application Number PCT/JP2006/303949
PCT International Filing date 2006-03-02
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2005-062238 2005-03-07 Japan