JP4115029B2 - Polyester composite fiber for stretch woven and knitted fabric - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polyester composite fiber for stretch woven or knitted fabric that is rich in bulk and has an unprecedented soft texture.
[0002]
[Prior art]
In order to obtain a woven or knitted fabric having a stretch function, it is well known to use a latent crimpable conjugate fiber obtained by joining two kinds of polyesters having different intrinsic viscosities in a side-by-side manner. When this latent crimpable composite fiber is crimped in the state of a yarn or a woven or knitted fabric to develop a crimp and used as a woven or knitted fabric having stretch performance, a three-dimensional crimp form of the yarn The crimp performance greatly affects the stretch performance of the fabric.
[0003]
Conventionally, in order to obtain such a latently crimpable polyester composite fiber, the difference in intrinsic viscosity between the two polyesters has been increased as much as possible, and the difference in shrinkage when made into fibers has been increased. In order to improve, efforts have been made to straighten the joint surfaces of both polyesters in the fiber cross section, and various proposals have been made for these composite fibers.
[0004]
For example, when the difference in intrinsic viscosity between two types of polyester is large, the discharge yarn is bent during melt spinning. Further, when the intrinsic viscosity difference is further increased, the bending proceeds excessively, and the yarn adheres to the spinneret, resulting in cutting, and stable spinning cannot be performed. Accordingly, in a die in which polymers having different viscosities are discharged from a pair of discharge holes to form a side-by-side type composite fiber, each pair of discharge holes is inclined with respect to a direction perpendicular to the die surface. There has been proposed a melt spinning die (Japanese Patent Publication No. 61-60163) in which the angle, the distance between a pair of discharge holes, and the like are regulated.
[0005]
When spinning is performed using this melt spinning die, the joint surfaces of the two types of polyester in the fiber cross section become linear. In this case, even if the intrinsic viscosity difference between the two types of polyester is large, the spinning operability is good, but since the joint surface of the two types of polyester is linear, the three-dimensional crimp form of the crimps that are manifested is small, There was a problem that crimps per unit length were developed so much that jamming occurred between single yarns, resulting in a flat texture lacking in bulkiness when formed into a woven or knitted fabric.
[0006]
[Problems to be solved by the invention]
The present invention provides a polyester composite fiber for stretchable woven and knitted fabrics, which has a high bulkiness and becomes a stretchable woven or knitted fabric having an unprecedented soft texture if the above problems are solved and knitted or woven. This is a typical issue.
[0007]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have curved the joint surface shape of both polyesters in the fiber cross section within a specific range, and the Young's modulus of the yarn is within a specific range. It has been found that a polyester composite fiber capable of simultaneously imparting bulkiness, unprecedented soft texture, and stretchability to a fabric obtained by weaving and knitting has been achieved. .
[0008]
That is, in the present invention, polytrimethylene terephthalate having a repeating unit of trimethylene terephthalate of 85% or more is used as two types of polyesters having different intrinsic viscosities, and the two types of polyesters are combined in a side-by-side manner, and the cross section of the fiber It is a fiber in which the joint surface shape of both polyesters is curved, the intrinsic viscosity of low intrinsic viscosity polyester is 0.6 to 1.10, the intrinsic viscosity of high intrinsic viscosity polyester is 0.7 to 1.30, and between both polyesters The linear viscosity X of the high-viscosity polyester and the straight line X passing through the center of the line segment ab connecting the two contact points a and b between the joint surface and the fiber outer periphery is set to 0.1 or more. When the intersection point with the outer circumference is c, the intersection point with the joint surface is d, and the intersection point between the line segment cd and the line segment ab is e, the ratio de / cd of the length between the line segment de and the line segment cd A gist is a polyester composite fiber for stretchable woven or knitted fabric, which satisfies the following formula (1), has a Young's modulus of yarn of 40 g / D or less, and a crimp rate of 30% or more. is there.
0.05 ≦ de / cd ≦ 0.80 (1)
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
[0010]
The composite fiber of the present invention is a fiber in which two types of polyesters having different intrinsic viscosities are bonded to each other in a side-by-side manner, and the bonding surface shape of the two types of polyesters in the fiber cross section needs to be curved. . If the joint surfaces of two types of polyester in the fiber cross-section are linear, the three-dimensional crimp form of crimps generated by the shrinkage treatment becomes small, and very many crimps appear per unit length. A jam occurs between the yarns. For this reason, the bulkiness of the woven or knitted fabric is lowered.
[0011]
FIG. 1 is a cross-sectional view showing one embodiment of the conjugate fiber of the present invention. In FIG. 1, the intersection of the straight line X passing through the center of the line segment ab connecting the two contact points a and b of both polyesters and the fiber outer periphery and orthogonal to the line segment ab and the fiber outer periphery of the high-viscosity polyester. C, the intersection with the joint surface is d, and the intersection between the line segment cd and the line segment ab is e. In the conjugate fiber of the present invention, the ratio of the lengths of the line segment de and the line segment cd (hereinafter referred to as de / cd) needs to be 0.05 to 0.80 as in the formula (1). When this ratio is less than 0.05, the joint surfaces of both polyesters in the fiber cross section become linear, and the bulkiness of the woven or knitted fabric becomes low. On the other hand, if this ratio exceeds 0.80, the three-dimensional crimp form of crimps developed by the shrinkage treatment becomes large. In order to make this ratio exceed 0.80, the intrinsic viscosity difference between the two polyesters. Therefore, there is a problem that the discharged yarn is bent and adheres to the die surface during melt spinning, and thus the yarn is cut and stable spinning cannot be performed.
[0012]
In the conjugate fiber of the present invention, the yarn Young's modulus needs to be 40 g / D or less. When the Young's modulus of the yarn is greater than 40 g / D, the texture of the woven or knitted fabric becomes stiff and lacks a soft feeling. A method for setting the Young's modulus to 40 g / D or less is not particularly limited. For example, a method in which the yarn is composed of a polyester having a relatively flexible structure is preferable. Among these, polytrimethylene terephthalate (hereinafter abbreviated as PTT) excellent in stretchability, dimensional stability, and light resistance is preferable.
[0013]
In addition, as long as the effects of the present invention are not impaired, there is no particular problem even if a small amount of a copolymer component is contained. Examples of the copolymer component include 5-sodium sulfoisophthalic acid, isophthalic acid, phthalic anhydride, and naphthalenedicarboxylic acid. Aromatic dicarboxylic acid components such as adipic acid, sebacic acid and azelaic acid, hydroxycarboxylic acid components such as 4-hydroxybenzoic acid and ε-caprolactone, ethylene glycol, 1,4 butanediol, 1 Diol components such as ethylene oxide adducts of 1,2-cyclohexanedimethanol and 2,2-bis {4- (β-hydroxy) phenyl} propane.
[0014]
Further, the conjugate fiber of the present invention needs to have a crimp rate of 30% or more when the yarn is contracted with boiling water. If the crimping ratio is lower than 30%, the stretchability of the woven or knitted fabric obtained from this fiber becomes poor, and it is not suitable for a stretchable woven or knitted fabric. As a method of setting the crimp rate to 30% or more, a method of adjusting the intrinsic viscosity difference between the two polyesters is preferable. And in order to make the crimp rate of the composite fiber 30% or more, polyester having an intrinsic viscosity of 0.6 to 1.10 on the low intrinsic viscosity side, 0.7 to 1.30 on the high intrinsic viscosity side It is preferable to use polyester having intrinsic viscosity and combine them so that the difference in intrinsic viscosity between the two polyesters is 0.1 or more.
[0015]
In the composite fiber of the present invention, a matting agent such as titanium oxide, an antioxidant such as a hindered phenol compound, an ultraviolet absorber, and a light stabilizer, as necessary, unless the effects of the present invention are impaired. , Pigments, flame retardants, antibacterial agents, conductivity-imparting agents, and the like.
[0016]
Next, the example of the manufacturing method of the composite fiber of this invention is demonstrated.
First, two types of polyesters with different intrinsic viscosities are melted using a composite spinning device, weighed in separate metering holes, merged into a side-by-side type on the back of the die, and the same at a spinning temperature of 240 to 290 ° C. After discharging from the discharge hole and cooling the spun yarn, an oil agent is applied and taken up at a speed of 1000 to 4000 m / min and wound. Next, a drawing heat treatment is performed using a twisting machine to obtain the conjugate fiber of the present invention.
[0017]
【Example】
EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.
In addition, the measuring method and evaluation method in an Example are as follows.
(1) Intrinsic viscosity (η)
The measurement was carried out at a temperature of 25 ° C. using a mixture of equal amounts of phenol and ethane tetrachloride as a solvent.
(2) Crimp rate The obtained composite fiber multifilament is scraped five times with a measuring machine having an outer circumference of 1.125 m, and doubled, and left for 30 minutes under a load of 1/6000 g / D. Next, boiling water treatment is performed for 30 minutes while the load is applied, and the treated sample is dried for 30 minutes. A load of 1/500 g / D is applied to the dried sample, and the length A is measured. Next, the load of 1/500 g / D is removed, the length B is measured with a load of 1/20 g / D, and the following formula is calculated.
Crimp rate (%) = [(B−A) / B] × 100
(3) Evaluation of spinning operability Evaluated by the number of cuts when spinning for 24 hours with 16 spindles, and ○ and Δ were accepted criteria.
0 times: ○, 1-2 times: △, 3 times or more: ×
(4) Evaluation of stretchability and texture Using 50 denier / 24 filament polyethylene terephthalate (hereinafter abbreviated as PET) drawn warp and weaving in a plain weave structure using the composite fiber obtained as weft. The fabric was scoured, treated in boiling water at 100 ° C. for 30 minutes, and then air-dried, and sensory evaluation was conducted by 10 panelists. Evaluation was performed with the number of persons judged to have a soft texture with stretchability when pulled in the weft direction, and ○ and Δ were used as acceptance criteria.
9 or more: ○, 7-8: △, 6 or less: ×
(5) Comprehensive evaluation In consideration of each evaluation item described above, the evaluation was comprehensively made with ◯, △, and ×, and ○ and △ were used as acceptance criteria.
[0018]
Example 1
High viscosity side PTT (A) containing 0.4% by weight of titanium oxide and having an intrinsic viscosity of 1.01, and low viscosity side PTT containing 0.4% by weight of titanium oxide and having an intrinsic viscosity of 0.78 (A) B) is melted and discharged from the same spinneret having a round cross-sectional shape hole with a hole diameter of 0.6 mm so that the volume ratio of PTT (A) and (B) in the cross section of the fiber is 1: 1. Was adjusted and spinning was performed at a spinning temperature of 260 ° C.
[0019]
Next, after the spinning yarn is cooled and solidified with an air flow, 0.7% by weight of an oil agent is applied, the yarn is divided into two and taken up at a speed of 2800 m / min, and a side-by-side type of 82.5 denier. Of semi-undrawn yarn was obtained. The discharge rate at this time was adjusted so that the fineness after stretching would be 50 denier.
Next, the obtained semi-undrawn yarn was drawn 1.65 times at 70 ° C. and then heat-treated on a hot plate at 160 ° C. to obtain a 50 denier / 12 filament composite fiber.
[0020]
Examples 2-3 and Comparative Examples 1-2
A composite fiber was produced in the same manner as in Example 1 except that the intrinsic viscosity of PTT (B) was changed as shown in Table 1 in order to change de / cd in the fiber cross section.
[0021]
Comparative Example 3
In order to change de / cd, ethylene oxide adduct of 2,2-bis {4- (β-hydroxy) phenyl} propane as the third component was added to PTT (A) as the third component. A bicomponent multifilament was produced in the same manner as in Example 1 except that 2 mol% was copolymerized and the intrinsic viscosity difference shown in Table 1 was added to PTT (B).
[0022]
Comparative Example 4
High viscosity side PET (A) containing 0.4% by weight of titanium oxide and having an intrinsic viscosity of 0.67, and low viscosity side PTT containing 0.4% by weight of titanium oxide and having an intrinsic viscosity of 0.46 ( B) is melted, and the discharge ratio is such that the volume ratio of PET (A) and (B) in the cross section of the fiber is 1: 1 from the same spinneret having 24 holes and a round sectional shape hole of 0.8 mm in diameter. Was adjusted and spinning was performed at a spinning temperature of 295 ° C.
[0023]
Next, after spinning and solidifying the spun yarn with an air flow, 0.7% by weight of an oil agent is applied, and the yarn is divided into two parts and taken up at a speed of 3300 m / min. An undrawn yarn was obtained. The discharge rate at this time was adjusted so that the fineness after stretching would be 50 denier. Further, the obtained semi-undrawn yarn was drawn 1.5 times at 70 ° C. and then heat-treated on a hot plate at 150 ° C. to obtain a 50 denier / 12 filament composite fiber. The evaluation results of the composite fiber multifilaments obtained in Examples 1 to 3 and Comparative Examples 1 to 4 are also shown in Table 1.
[0024]
[Table 1]
[0025]
As is apparent from Table 1, the composite fiber multifilaments obtained in Examples 1 to 3 have few cut yarns during spinning, and the fabric after heat treatment in which these composite fiber multifilaments are arranged on the wefts is in the weft direction. It was a soft texture with bulkiness and stretchability. In addition, the crimp rate as an index of stretchability is 30% or more, and the Young's modulus as an index of softness is 40 g / D or less, which has a very large correlation with the sensory evaluation of the fabric. Met.
[0026]
On the other hand, in Comparative Example 1, since the difference in intrinsic viscosity between the two polyesters was too large, the discharged yarn was bent and adhered to the die surface during melt spinning, and spinning was impossible. In Comparative Example 2, since the de / cd was too small, the crimped three-dimensional crimp form was small, the fabric lacked bulkiness, and the crimp rate was also low. Next, in Comparative Example 3, the third component was copolymerized with PTT (A), so the crimp rate was an appropriate value. However, since de / cd was too small, the crimped form was small. As a result, the woven fabric lacked bulkiness. Furthermore, in Comparative Example 4, since the use of PET, the texture of the fabric was hard, and a fabric with a soft feeling could not be obtained. The Young's modulus was also higher than 40 g / D.
[0027]
【The invention's effect】
According to the present invention, there is provided a polyester composite fiber for stretchable woven or knitted fabric that becomes a stretchable woven or knitted fabric that is rich in bulk and has an unprecedented soft texture when knitted or woven.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing one embodiment of a polyester conjugate fiber for stretchable woven or knitted fabric of the present invention.
[Explanation of symbols]
a Contact point between both polyester joint surfaces and fiber outer periphery.
b Contact points between both polyester joint surfaces and the outer periphery of the fiber.
X A straight line passing through the center of the line segment ab and orthogonal to the line segment ab.
c Intersection of the straight line X and the fiber outer periphery of the high viscosity polyester.
d Intersection of straight line X and both polyester joint surfaces.
e Intersection of line segment ab and straight line X.

Claims (1)

Polytrimethylene terephthalate with 85% or more of repeating units of trimethylene terephthalate is used as two types of polyesters with different intrinsic viscosities. Is a curved fiber, the intrinsic viscosity of the low intrinsic viscosity polyester is 0.6 to 1.10, the intrinsic viscosity of the high intrinsic viscosity polyester is 0.7 to 1.30, and the intrinsic viscosity difference between the two polyesters is 0. and .1 least two contact points a of the joining surface and the fiber outer circumference through the center of the connecting b segment ab, the intersection of the fiber outer circumference of the straight line X and the high viscosity side polyester orthogonal to the line segment ab c When the intersection with the joint surface is d and the intersection between the line segment cd and the line segment ab is e, the length ratio de / cd of the line segment de and the line segment cd satisfies the following formula (1). And the Young's modulus of the yarn is 40 g / D or less, stretch woven or knitted fabric for polyester composite fiber characterized by crimp is 30% or more.
0.05 ≦ de / cd ≦ 0.80 (1)