JP2001181929A - Highly shrinkable polyester fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a highly shrinkable polyester fiber which maintains a high thermal shrinkage rate and simultaneously has fiber flexibility also after shrunk. SOLUTION: This highly shrinkable polyester fiber comprises modified polytrimethylene terephthalate copolymerized with isophthalic acid component and/or phthalic acid component in an amount of 5 to 15 mol.% based on all dicarboxylic acid components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly shrinkable polyester fiber, and more particularly, to a highly shrinkable polyester fiber having elasticity even after being shrunk by heat treatment.

[0002]

BACKGROUND OF THE INVENTION As is well known, polyester is
Due to its excellent performance, it is widely used for fibers, resins, films and the like. In particular, polyester fibers have excellent properties such as excellent dimensional stability, heat resistance, light resistance, and the like, and are strong and hard to wrinkle. Therefore, polyester fibers are used in all fields regardless of clothing or non-clothing.

[0003] In recent years, its applications have been expanded, and improvements have been made to meet various demands. For example, polyester fibers having high shrinkage performance are disclosed in JP-A-2-13.
No. 9409, JP-A-3-90616, etc.
Copolymerized polyester fibers composed of polyethylene terephthalate obtained by copolymerizing components have been proposed. As described above, a highly shrinkable polyester fiber can be obtained by copolymerizing the third component with polyethylene terephthalate, but the polyester fiber thus obtained has a high shrinkage rate, but the flexibility of the fiber after shrinkage is greatly reduced. I do. Therefore, it cannot be said that it is very suitable for applications requiring high elongation after shrinkage and relatively gentle shrinkage stress.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and to obtain a high shrinkage polyester fiber while maintaining a high heat shrinkage while maintaining a high heat shrinkage. An object of the present invention is to provide a highly shrinkable polyester fiber having flexibility.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that a fiber made of a specific copolymerized polyester has a high heat shrinkage while maintaining a high heat shrinkage. The inventors have found that they also have flexibility, and have reached the present invention.

That is, an object of the present invention is to provide a terephthalic acid component having a content of 80 to 95 mol% and an isophthalic acid component and / or a phthalic acid component having a content of 5 to 5 mol% based on the total dicarboxylic acid component.
-15% by mole, comprising 90% by mole or more of trimethylene glycol based on the total glycol components, and simultaneously satisfying the following requirements (a) to (e): high shrinkage This can be achieved with polyester fibers. (A) The intrinsic viscosity of the fiber is in the range of 0.5 to 1.0. (B) The tensile strength of the fiber is 1.5 to 4.5 cN / dtex.
Be in the range. (C) Shrinkage after dry heat treatment at 150 ° C. for 10 minutes is 8 to 2
Be within the range of 5%. (D) The tensile strength retention after dry heat treatment at 150 ° C. for 10 minutes is in the range of 80 to 100%. (E) The tensile elongation retention after dry heat treatment at 150 ° C. for 10 minutes is in the range of 100 to 150%.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The copolymerized polyester used as the highly shrinkable polyester fiber of the present invention has a terephthalic acid component content of 80 to 95 mol% and an isophthalic acid component and / or phthalic acid component content of 5 to 15 mol% based on all dicarboxylic acid components. It is necessary to be.

If the total amount of the isophthalic acid component and / or the phthalic acid component is less than 5 mol%, the shrinkage is not sufficient, which is not preferable. On the other hand, if it is more than 15 mol%, it is not preferable because it is disadvantageous in terms of cost, fusion of the copolyester chips is liable to occur, and the strength of the obtained fiber is reduced. The isophthalic acid component and / or the phthalic acid component is preferably in the range of 7 to 14 mol%, more preferably in the range of 8 to 12 mol%.

Further, in the copolymerized polyester of the present invention, it is necessary that trimethylene glycol accounts for 90 mol% or more based on all glycol components. If the trimethylene glycol is less than 90 mol%, the strength retention and elongation retention after the dry heat treatment will decrease.

The intrinsic viscosity (measured in an orthochlorophenol solvent at 30 ° C.) of the copolymerized polyester of the present invention is as follows:
It is preferably 0.52 to 1.1. When the intrinsic viscosity is less than 0.52, the mechanical properties of the copolymerized polyester are reduced, and the strength of the finally obtained fiber tends to be insufficient. On the other hand, if it exceeds 1.1, the fluidity at the time of melting of the polymer tends to decrease, and the moldability tends to decrease.
The intrinsic viscosity of the copolymerized polyester is preferably in the range of 0.53 to 1.1, and more preferably in the range of 0.55 to 0.90.

The copolymerized polyester of the present invention has a content other than a terephthalic acid component, an isophthalic acid component, a phthalic acid component and a trimethylene glycol component in a range that does not impair the properties thereof, preferably in a range of 5 mol% or less based on all dicarboxylic acid components. May be copolymerized. Examples of these copolymer components include naphthalenedicarboxylic acid component, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, benzophenone dicarboxylic acid, phenylindane dicarboxylic acid, 5-sulfoxyisophthalic acid metal salt, and 5-sulfoxyisophthalic acid phosphonium. Aromatic dicarboxylic acids such as salts, ethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, decamethylene glycol, neopentylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polytetramethylene glycol , Cyclohexanediol, aliphatic glycols such as cyclohexanedimethanol, o-xylylene Chole, m-xylylene glycol, p-xylylene glycol, 1,4-bis (2-hydroxyethoxy) benzene, 1,4-bis (2-hydroxyethoxyethoxy) benzene, 4,4'-bis (2- (Hydroxyethoxy) biphenyl, 4,4′-bis (2-hydroxyethoxyethoxy) biphenyl, 2,2-bis [4
-(2-hydroxyethoxy) phenyl] propane,
2,2-bis [4- (2-hydroxyethoxyethoxy) phenyl] propane, 1,3-bis (2-hydroxyethoxy) benzene, 1,3-bis (2-hydroxyethoxyethoxy) benzene, 1,2- Bis (2-hydroxyethoxy) benzene, 1,2-bis (2-hydroxyethoxyethoxy) benzene, 4,4′-bis (2
-Hydroxyethoxy) diphenylsulfone, 4,4 '
Aromatic glycols such as -bis (2-hydroxyethoxyethoxy) diphenylsulfone, hydroquinone, 2,2
And diphenols such as -bis (4-hydroxyphenyl) propane, resorcin, catechol, dihydroxynaphthalene, dihydroxybiphenyl and dihydroxydiphenylsulfone. These may be used alone or in combination of two or more.

The above-mentioned polyester can be produced by a conventionally known method. For example, the above-mentioned dicarboxylic acid component is subjected to an esterification reaction with trimethylene glycol, or the lower alkyl ester component of the above-mentioned dicarboxylic acid is mixed with trimethylene glycol. A transesterification reaction in the presence of a transesterification catalyst to obtain a bisglycol ester and / or an initial condensate thereof, followed by a polycondensation reaction in the presence of a polycondensation catalyst, or isophthalic acid used as a copolymerization component; The aliphatic dicarboxylic acid and / or trimethylene glycol ester thereof is added to the bisglycol ester of terephthalic acid component and trimethylene glycol and / or the prepolymer thereof, and then polycondensed in the presence of a polycondensation catalyst. A method can be adopted.

In the copolymerized polyester used in the present invention, a small amount of additives such as a lubricant, a pigment,
Dyes, antioxidants, solid-state polymerization accelerators, optical brighteners, antistatic agents, antibacterial agents, ultraviolet absorbers, light stabilizers, heat stabilizers,
It may contain a light-shielding agent, a matting agent, and the like.

The highly shrinkable polyester fiber of the present invention needs to have an intrinsic viscosity in the range of 0.5 to 1.0. When the intrinsic viscosity is less than 0.50, the mechanical strength of the finally obtained fiber decreases. On the other hand, if it exceeds 1.0, the strength becomes too high and handling becomes difficult. The intrinsic viscosity of the copolymerized polyester is preferably in the range of 0.52 to 0.90, and more preferably in the range of 0.55 to 0.80.

The high-shrinkable polyester fiber of the present invention needs to have a tensile strength in the range of 1.5 to 4.5 cN / dtex. When the tensile strength is less than 1.5 cN / dtex,
The performance of the finally obtained fiber product is insufficient, while if it exceeds 4.5 cN / dtex, the product is too strong and handling becomes difficult. The tensile strength is 2.0-4.
The range of 0 cN / dtex is preferable, and 2.5 to 3.5 c
The range of N / dtex is more preferred.

The highly shrinkable polyester fiber of the present invention has 15
The shrinkage after dry heat treatment at 0 ° C. for 10 minutes needs to be in the range of 8 to 25%. If the shrinkage ratio is less than 8%, the performance as shrinkable fibers is insufficient, and if it exceeds 25%, the strength after shrinkage is reduced. The shrinkage is 9 to 2
A range of 0% is preferable, and a range of 10 to 18% is more preferable.

The high-shrinkable polyester fiber of the present invention has 15
Tensile strength retention after dry heat treatment at 0 ° C for 10 minutes is 80-1
It must be in the range of 00%. When the tensile strength retention is less than 80%, the performance as a shrinkable fiber is insufficient, and when it exceeds 100%, the strength of the product is too high and handling becomes difficult. The tensile strength retention after the dry heat treatment is preferably in the range of 85 to 99%, more preferably in the range of 90 to 98%.

The highly shrinkable polyester fiber of the present invention has 15
Tensile elongation retention after dry heat treatment at 0 ° C for 10 minutes is 100 ~
It must be in the range of 150%. Tensile elongation retention rate is 1
If it is less than 00%, the performance as a shrinkable fiber is insufficient, and if it exceeds 150%, the strength after shrinkage becomes insufficient, which is not preferable. The tensile elongation retention is 105 to 145.
% Is preferable, and a range of 110 to 140% is more preferable.

In producing the high-shrinkage polypolyester fiber of the present invention, there is no particular limitation on the melt-spinning-drawing step, and it can be produced by a conventionally known step for producing ordinary polyester fiber. After spinning, the undrawn yarn is wound and drawn separately, the undrawn yarn is continuously drawn without being wound once, and after the melt-spinning, the undrawn yarn is cooled and solidified in a coagulation bath, and then heated. A method of stretching in a medium or under contact heating such as a heating roller or by a non-contact type heater is employed.

Here, when the melt-spun undrawn yarn is drawn, the total drawing ratio is set to be in the range of 2.5 to 6.0 times so that the finally obtained fiber is subjected to dry heat treatment. The strength retention and elongation retention at a later stage can be made compatible with each other at a higher level, and the yarn breakage rate in the stretching step is low, and the productivity is further improved. The total stretching ratio is more preferably in the range of 2.8 to 5.5 times, and particularly preferably in the range of 3.0 to 5.0 times.

The stretching step may be performed only in one-stage stretching or may be performed in two or more stages. For example, when a two-stage stretching method is adopted, the stretching ratio in the first stage is 2.0 to 5.5.
And the second-stage stretching ratio may be adjusted to about 1.0 to 2.0 times, and the total stretching ratio may be adjusted to 2.5 to 6.0 times.

In the method for producing a highly shrinkable polyester fiber of the present invention, the shape of the die used at the time of spinning is not limited, and any of a circular shape, an irregular shape, a solid shape, and a hollow shape can be adopted.

In addition, as long as the object of the present invention is achieved, a composite having a composite form such as a side-by-side type or a core-sheath type with a polymer different from the copolymerized polyester constituting the high shrinkage polyester fiber of the present invention. It may be a fiber.

[0024]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the invention. The parts in the examples are parts by weight. Various properties were evaluated by the following methods. (1) Intrinsic viscosity (IV): Measured at 30 ° C. using orthochlorophenol as a solvent, and determined from the relative viscosity by an ordinary method. (2) Tensile strength and tensile elongation: Measured according to the method described in JIS L1070. (3) dry heat treatment, dry heat shrinkage, tensile strength retention after dry heat,
Tensile elongation retention: 20c in a dryer heated to 150 ° C
The test yarn having a length of m was hung and held for 10 minutes. The length of the test yarn before and after the dry heat treatment was measured to determine the dry heat shrinkage. The tensile strength and tensile elongation of the test yarn before and after the dry heat treatment were measured, and the tensile strength retention and the tensile elongation retention were determined.

Example 1 Dimethyl terephthalate 90
Parts, 10 parts of dimethyl isophthalate, 54.9 parts of trimethylene glycol and 0.078 part of titanium tetrabutoxide as a catalyst were charged into a reactor equipped with a stirrer, a rectification column and a methanol distillation condenser, and gradually heated from 140 ° C. The ester exchange reaction was carried out while distilling the methanol produced as a result of the reaction out of the system. Three hours after the start of the reaction, the internal temperature reached 210 ° C.

Next, the obtained reaction product was transferred to another reactor equipped with a stirrer and a glycol distillation condenser, and the temperature was gradually raised from 210 ° C. to 265 ° C., and the pressure was reduced from normal pressure to a high vacuum of 70 Pa. The polymerization reaction was performed while reducing the pressure. The melt viscosity of the reaction system is tracked and the intrinsic viscosity (I
When V) reached 0.82, the polymerization reaction was terminated.

The molten polymer was extruded from the bottom of the reactor into strands in cooling water, and cut into chips using a strand cutter. After the obtained chip was dried at 160 ° C. for 6 hours, it was melted at 270 ° C. using an extrusion spinning machine having a spinneret having 24 circular spinning holes having a hole diameter of 0.27 mm, and a discharge rate of 14.5 g / min. The unstretched yarn obtained was subjected to a stretching machine having a heating roller at 60 ° C. and a plate heater at 160 ° C., and was stretched at a draw ratio of 3.8 times. .35dt
An ex / 24 filament drawn yarn was obtained. The tensile strength, tensile elongation, dry heat shrinkage, tensile strength after dry heat treatment, and tensile elongation of the obtained drawn yarn were measured. Table 1 shows the results.

Example 2 The same procedure as in Example 1 was carried out except that the transesterification reaction was carried out without adding 10 parts of dimethyl isophthalate, and 7.65 parts of phthalic anhydride were added after the completion of the transesterification reaction. The operation was performed. Table 1 shows the results.

COMPARATIVE EXAMPLE 1 Polyethylene terephthalate having an intrinsic viscosity of 0.64 was obtained using an extrusion spinning machine having a spinneret equipped with 24 circular spinning holes having a hole diameter of 0.27 mm.
Melted at 5 ° C, discharge rate 14.5g / min, take-off speed 400
The unstretched yarn obtained is spun at m / min, and the obtained unstretched yarn is subjected to a stretching treatment machine having a heating roller at 85 ° C. and a plate heater at 160 ° C., and is stretched at a stretching ratio of 4.3 times to 83.2.
A 5dtex / 24 filament drawn yarn was obtained.

Comparative Example 2 The same operation was performed as in Example 1, except that polytrimethylene terephthalate having an intrinsic viscosity of 0.80 was used instead of the copolymerized polyester. Table 1 shows the results.

[0031]

[Table 1]

[0032]

The highly shrinkable polyester fiber of the present invention is
While having excellent heat shrink performance, it also has excellent strength and elongation after heat treatment, and can be used for a wide range of applications such as shrink yarn applications requiring flexibility.

Claims (1)

[Claims] 1. The terephthalic acid component is in the range of 80 to 95 mol% based on the total dicarboxylic acid component, the isophthalic acid component and / or the phthalic acid component is in the range of 5 to 15 mol%, and trimethylene is based on the total glycol component. Glycol is a copolymerized polyester occupying 90 mol% or more, and simultaneously satisfies the following requirements (a) to (e):
High shrinkage polyester fiber. (A) The intrinsic viscosity of the fiber is in the range of 0.5 to 1.0. (B) The tensile strength of the fiber is 1.5 to 4.5 cN / dtex.
Be in the range. (C) Shrinkage after dry heat treatment at 150 ° C. for 10 minutes is 8 to 2
Be within the range of 5%. (D) The tensile strength retention after dry heat treatment at 150 ° C. for 10 minutes is in the range of 80 to 100%. (E) The tensile elongation retention after dry heat treatment at 150 ° C. for 10 minutes is in the range of 100 to 150%.