(57) A manufacturing method of polyester fiber having improved light fastness is provided,
which comprises copolymerizing dicarboxylic acid, diol component and the ester forming
monomer into a copolyester, wherein said ester forming monomer is present in an amount
of 0.05 mole % above based upon the total dicarboxylic acid components and is represented
by the following formula (1)
R
2OOC-R
1-COOR
3
(wherein R
1 is a naphthalene ring, R
2 and R
3 are selected from group of hydrogen atoms or C
1∼C
4 alkyl, and R
2 is independent from R
3, it can be the same or different with R
3; the position of substitute group for the naphthalene ring on the ester forming monomer
can be: -2,3-, -2,5-, -2,6-, -2,7-, -1,2-, -1,3-, -1,4-, -1,5-, -1,6-, -1,7-, -1,8-),
subjecting the formed copolyester component to spin-draw process to obtain fiber which
possess excellent light fastness after dyeing. Said fiber is suitable for automobile
interior decoration, curtain and outdoor application and can keep fresh color without
fading even being exposed to sunlight for a long time.
FIELD OF THE INVENTION
[0001] The present invention relates to a manufacturing method of polyester fiber having
improved light fastness, particularly relates to a method comprising copolymerizing
polyester and ester forming monomer having the structure of naphthalene ring into
copolyester, subjecting the copolyester component formed to spin-draw process to obtain
fiber which has excellent light fastness after dyeing, can prevent from the cracking
caused by ultraviolet radiation, is suitable for the automobile interior decoration,
curtain and outdoor application, and can keep fresh color without fading even being
exposed to sunlight for a long time.
DESCRIPTION OF THE PRIOR ART
[0002] Polyester has excellent physical property, therefore is widely used in various application
such as fiber, membrane, engineering plastic, etc., wherein the fiber can be used
in home decoration, automobile interior decoration, industrial fiber, etc, besides
garment application. However, with respect to the automobile interior decoration,
as the final products made from fiber are frequently exposed to the sunlight, the
high temperature and the ultraviolet radiation can cause the dyeing molecule in the
fiber to decompose and crack, leading to fading.
[0003] In pursuit of improved polyester fiber, various applications have been put forwarded
to obtain desirable light fastness. For example, the U.S. Pat. No. 4,789,382 disclosed
that adding ultraviolet radiation absorbent like benzophenone in the dye bath to improve
light fastness. The U.S. Pat. No. 4,110,301 disclosed a photo rearrangement compound
having the ability of improving light fastness of polyester fiber; wherein the photo
rearrangement compound can be added to the dye bath or added during the spinning process.
The Japan laid open publication No. 1990-41468 disclosed that adding ultraviolet radiation
absorbent like benzotriazole in the dye bath to improve light fastness. Moreover,
the Japan laid open publication No. 1992-339885 disclosed that adding ultraviolet
radiation absorbent like benzotriazole and benzophenone in the dye bath together to
improve light fastness. Furthermore, the Japan laid open publication No. 1987-276018
disclosed that adding three kinds of components such as ultraviolet radiation absorbent
like benzotriazole, tetramethyl piperidine compound and aliphatic polyester polyol
during the spinning process to improve light fastness. The Japan laid open publication
No. 1992-240212 disclosed that adding ultraviolet radiation absorbent like acrylic
copolymer comprising 2-hydroxy-4-( methacryloyloxy ethoxy ) benzophenone to improve
light fastness. The U.S. Pat. No. 4,189,476 disclosed that applying aromatic polyester
comprising 10 to 23 mole % of 2,6-dioxy naphthalene to produce melting polyester fiber
possessing high elongation and high modulus properties, wherein the using amount of
ester forming monomer like 2,6-dioxy naphthalene is high as 10 to 23 mole % and the
melting polyester fiber is of high elongation and high modulus. However the effect
of above mentioned proposals are not desirable, there is a continuing need for improved
polyester fiber.
[0004] In the above described Japan laid open publication No. 1987-276018, combining tetramethyl
piperidine compound with ultraviolet radiation absorbent like benzotriazole as well
as aliphatic polyester polyol are used to improve light fastness, however, there's
no improvement to the phenomenon of bad sublimation degree of ultraviolet radiation
absorbent like benzotriazole, and as the aliphatic polyester polyol added is a low
molecule substance, it lead to the disadvantage that the fiber has a lower physical
property.
[0005] In the above described Japan laid open publication No. 1992-240212, an ultraviolet
radiation absorbent like acrylic copolymer comprising 2-hydroxy-4 ( methacryloyloxy
ethoxy ) benzophenone is applied, however the compound has undesired heat resistance,
when it is added into the polymer during late polymerization process, the luster was
changed to yellow sharply, leads to the fiber exhibiting yellowish luster. Furthermore,
adding powdery ultraviolet radiation absorbent during post polymerization process
puts difficulties in the way of production and operation.
[0006] As for the method of adding ultraviolet radiation absorbent like benzophenone and
ultraviolet radiation absorbent like benzotriazole in the dye bath, as the ultraviolet
radiation absorbent like benzotriazole has an undesired sublimation degree, and the
ultraviolet radiation absorbent like benzophenone has an undesired affinity for polyester
fiber, effective absorption can not be achieved. In addition, both ultraviolet radiation
absorbent like benzophenone and ultraviolet radiation absorbent like benzotriazole
applied in the above described patents are yellow powder, this causes the fiber formed
exhibiting light yellow color, therefore leads to the adverse effect of dyeing offset.
Furthermore, the ultraviolet radiation absorbent added is a small molecule compound,
having not bonded with the polymer, therefore it can migrate to the fiber surface
during the post processing stage and the application stage, causing pollution; after
several times of application and washing, it has a lowered effective composition;
or after long time exposure, it shows some adverse results, like lower effectiveness,
etc. due to gradual decomposition.
OBJECT OF THE INVENTION
[0007] One object of the invention is to provide a method that can effectively improve light
fastness of fiber, that has no problems of lowered effective composition and problems
of pollution caused by ultraviolet radiation absorbent migrating to the fiber surface;
furthermore, the fiber produced has excellent whiteness and fresh color after dyeing,
without dyeing offset caused by ultraviolet radiation absorbent exhibiting yellowish.
Another object of the invention is to provide a polyester fiber that possesses excellent
and permanent light fastness property with white appearance and fresh color after
dyeing, and is suitable for automobile interior decoration and outdoor application.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0008] As a result of an intensive study, the inventor proposes the present invention for
the abovementioned objects, which relate to a fiber formed by copolymerizing the ester
forming monomer represented by formula (1) and polyester, said fiber possesses excellent
light fastness.
R
2OOC-R
1-COOR
3
(wherein R
1 is a naphthalene ring, R
2 and R
3 are selected from group of hydrogen atoms or C
1~C
4 alkyl, and R
2 is independent from R
3, it can be the same or different with R
3; the position of substitute group for the naphthalene ring on the ester forming monomer
can be: -2,3-, -2,5-, -2,6-, -2,7-, -1,2-, -1,3-, -1,4-, -1,5-, -1,6-, -1,7-, -1,8-).
[0009] As the compound is bonded into the polyester molecule in the form of copolymerization,
no such problems as pollution and undesired sublimation degree caused by compound
migrating to fiber surface therefore. Furthermore, as the final product is a copolyester,
fiber produced by the copolyester has excellent physical property, without reduction
of fiber physical property comparing with that of adding low molecule substance like
aliphatic polyester polyol. The copolyester obtained has excellent whiteness, no normal
yellowish problem caused by ultraviolet radiation absorbent, and fiber formed can
be dyed to fresh color without the defect of dyeing offset.
[0010] Examples of the ester forming monomers of formula (1) used in the present invention
include: 2,6-naphthalene-dicarboxylic acid, dimethyl-2,6-naphthalene-dicarboxylate,
diethyl-2,6-naphthalene-dicarboxylate, dipropyl-2,6-naphthalene-dicarboxylate, di-n-butyl-2,6-naphthalene-dicarboxylate,
2,5-naphthalene-dicarboxylic acid, dimethyl-2,5-naphthalene-dicarboxylate, diethyl-2,5-naphthalene-dicarboxylate,
dipropyl-2,5-naphthalene-dicarboxylate, di-n-butyl-2,5-naphthalene-dicarboxylate,
and similar compounds etc.
[0011] The addition amount of the ester forming monomers of formula (1), based upon the
total dicarboxylic acid components, is between 0.05~100 moles %. When the amount of
the ester forming monomers of formula (1) is less than 0.05 moles %, the fiber thus
obtained can not have good light fastness properties to fulfill the requirement in
the car seat application. Of course, the higher amount of the ester forming monomers
of formula (1) used, the better improvement can be achieved. The actual amount used
should be dependent upon the light fastness requirements of fibers. Basically, the
minimum amount used should be at least 0.05 moles %, based upon the total dicarboxylic
acid components, for effective improvement of light fastness. On the other hand, when
the addition amount of the ester forming monomers of formula (1) is more than 20 moles
% and less than 80 moles % based upon the total dicarboxylic acid components, the
copolyester formed is amorphous and can not go through the crystallization and drying
operation necessary for the spinning process of fibers. Hence, from the view point
of applications, the useful amount of the ester forming monomers of formula (1) is
between 0.05~20 moles % and between 80~100 moles % based upon the total dicarboxylic
acid components.
[0012] The addition manner of the above mentioned ester forming monomers of formula (1)
can be accomplished by the commonly known skills used in the polyester production.
For example: in one embodiment, feed the dicarboxylic acid monomers having naphthalene
structure together with terephthalic acid and ethylene glycol into reactor to conduct
the esterification reaction, followed by addition of commonly used antimony or germanium
compounds as the polycondensation catalyst, then proceed with polycondensation to
obtain the copolyester. In another embodiment, feed the ester dicarboxylane of monomers
having naphthalene structure together with dimethyl terephthalate, ethylene glycol
into reactor to conduct the ester exchange reaction, followed by addition of stabilizer,
antimony or germanium compounds as the polycondensation catalysts, then proceed with
polycondensation to obtain the copolyester. Yet in another embodiment, first conduct
the reaction between terephthalic acid and ethylene glycol. After the conversion ratio
has reached 85%, then feed the ester dicarboxylate of monomers having naphthalene
structure into the reaction system; followed by continuation of esterification reaction
until the conversion ratio has been over 96%, then add polycondensation catalysts
and proceed with polycondersation to obtain the copolyester desired.
[0013] The polyester in the present invention can be produced from dicarboxylic acid/ or
its ester derivatives and diols. The substantial examples of dicarboxylic acid and
its ester derivatives are as follows: aromatic dicarboxylic acids such as terephathlic
acid, isophthalic acid, 5-sulfoisophthalic acid sodium salt, 5-sulfisophthalic acid
tetra-n-butyl phosphonium salt, 5-sulfisophthalic acid ethyl tri-n-butyl phosphonium
salt; aliphatic dicarboxylic acids such as adipic acid, heptandioic acid, octandioic
acid, azelaic acid, sebacic acid; cycloaliphatic dicarboxylic acids such as 1,4-cyclohexane
dicarboxylic acid; alkyl esters of the above mentioned acids. The substantial examples
of diols are as follows: aliphatic diols such as ethlylene glycol, 1,2-propanediol,
1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, iso-pentanediol;
cyclic aliphatic diols such as 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol; aromatic
diols and ethylene oxide adducts of above mentioned diols such as p-dihydroxy phenyl,
2,2'-bis-(4-hydroxy phenyl) propane, bis-(4-hydroxy phenyl) naphthalene; polyglycols
such as polyethylene glycol, polypropylene glycol, copolymer of ethylene giycol and
propylene glycol, polytetramethylene glycol. If desired, the dicarboxylic acids and
diols used in the present invention can be selected from any kind of the above mentioned
diacids and diols and/ or any combination of the above mentioned diacids or diols
respectively.
[0014] For the end use applications, additives such as deluster agents, fluorescent brighteners,
antioxidants, bactericides, deodorants, antistatic agents, flame retardants, far infrared
radiating ceramic powders, can be incorporated into the copolyester if required.
[0015] The following is a brief description to the analytic method related to present invention.
(1) Intrinsic viscosity (IV):
Determined by measurements on 3/2 by weight mixed solvent of phenol and 1,1,2,2-tetrachloroethane
at 30°C.
(2) Gloss:
The L-value and b-value are analyzed by the color difference meter of Type TC-1800B
MK2 made by Tokyo Denshoku Company, Japan.
(3) Melting point:
Determined by DSC of PERKIN ELMER at temperature increase rate of 20°C/min.
(4) Light fastness:
Determined in accordance with Japanese Industrial Standard JIS L-0842 at temperature
of 83°C, after 349 hours of irradiation by carbon-arc lamp. Optical rotation is evaluated
by using JISL-0804 class of gray scale.
EXAMPLES
[0016] The present invention will be exemplified by following embodiments, but it will be
understood that the preferred embodiments are given for illustration of the invention
and are not intended to be limiting thereof.
EXAMPLE 1
[0017] Add 193.81 parts of dimethyl terephthalate, 0.244 parts of 2,6-dimethyl naphthalene
dicarboxylate (in an amount of 0.1 mole % based upon the total dicarboxylic acid components),
124 parts of ethylene glycol and 0.078 parts of manganese acetate into the reactor
to conduct the ester exchange reaction at the temperature of 165~230°C. When the distillate
reaches to the theoretical amount, add 0.0192 parts of trimethyl phosphate, 0.0864
parts of antimony acetate and 0.4 weight % of deluster agent (based upon the total
polyesters). Subsequently, raise the temperature of the reaction system to 280°C and
reduce the pressure gradually to 1 torr below to conduct polycondensation reaction.
The reaction shall not stop until the torque of mixer reaches to the desired value,
then use nitrogen to press the polymer into the water for cooling, finally pelletize
the polymer into chips. The copolyeseter obtained has an IV value of 0.0640, a melting
point of 253.5°C, L value of 78 and b value of 2.5. Melting spin the copolyester chips
by extruder at spinning temperature of 290°C and winding speed of 3200 meters/ min,
producing 125denier/36 filament of POY(partially oriented yarn), which is subsequently
subject to draw spinning into 75denier/ 36 filament. Weave to plain cloth and dye,
the light fastness measured is Class 3.
Condition of dyeing:
[0018]
Dyestuff: SUMIKARON YELLOW SE-3GL 2% o.w.f.
Bath ratio: 1: 50
Temperature of dyeing: 130°C
Time of dyeing: 60 minutes
EXAMPLE 2
[0019] Example 1 was repeated except that the adding amount of 2,6-dimethyl naphthalene
dicarboxylate was 0.5 mole %. The light fastness measured is Class 3.
EXAMPLE 3
[0020] Example 1 was repeated except that the adding amount of 2,6-dimethyl naphthalene
dicarboxylate was 1.0 mole %. The light fastness measured is Class 3~4.
COMPARATIVE EXAMPLE
[0021] Example I was repeated except that the adding amount of 2,6-dimethyl naphthalene
dicarboxylate was 0 mole % and the adding amount of dimethyl terephthalate was 194
parts. The polyester obtained has the L value of 78, and b value of 2.0 and Class
2 of light fastness.
EXAMPLE 4
[0022] Example 1 was repeated except that the adding amount of 2,6-dimethyl naphthalene
dicarboxylate was 10.0 mole %. The copolyester obtained has IV of 0.615, melting point
of 228°C, L value of 78 and b value of 3.0. Take 1 part of the copolyester obtained
with 9 parts of unmodified polyester without 2,6-dimethyl naphthalene dicarboxylate
and mix them evenly in the form of chip blends (final content of 2,6-dimethyl naphthalene
dicarboxylate is 1.0 mole %). Spin, draw, weave and dye the blends following the steps
of Example 1. Measured light fastness of polyester obtained is Class 3~4.
EXAMPLE 5
[0023] Example 4 was repeated to produce 10.0 mole % of 2,6-dimethyl naphthalene dicarboxylate.
Take 1 part of the copolyester obtained with 1 part of unmodified polyester without
2,6-dimethyl naphthalene dicarboxylate and mix them evenly in the form of chip blends
(final content of 2,6-dimethyl naphthalene dicarboxylate is 5.0 mole %). Follow the
steps of Example 4. Measured light fastness of polyester obtained is Class 4.
EXAMPLE 6
[0024] Example 4 was repeated except that 10.0 mole % of 2,6-dimethyl naphthalene dicarboxylate
was woven into filament directly. The light fastness measured is Class 4~5.
EXAMPLE 7
[0025] Example 1 was repeated except that the adding amount of 2,6-dimethyl naphthalene
dicarboxylate was 244.21 parts, i.e., 100 mole %. The copolyester obtained has IV
of 0.485, melting point of 265°C, L value of 77 and b value of 2.2.The light fastness
measured is Class 5.
EXAMPLES 8
[0026] Example 7 was repeated except that the adding amount of 2,6-dimethyl naphthalene
dicarboxylate was changed to 92 mole % of 2,6-dimethyl naphthalene dicarboxylate and
8 mole % of dimethyl terephthalate. The copolyester obtained has IV of 0.512, melting
point of 251°C, L value of 77 and b value of 1.6.The light fastness measured is Class
5.
COMPERATIVE EXAMPLE 2
[0027] Example 6 was repeated except that the adding amount of 2,6-dimethyl naphthalene
dicarboxylate was changed to 21 mole %. The copolyester obtained is amorphous, can
not go through the crystallization and drying process to produce fiber.
COMPERATIVE EXAMPLE 3
[0028] Add 1.5 weight % of ultraviolet radiation absorbent like acrylic copolymer comprising
2-hydroxy-4-( methacryloyloxy ethoxy ) benzophenone ( BASF UVA635L ), polyester obtained
exhibits obvious yellowish with L value of 65 and b value of 13.