JP2000239927A - Polyester conjugate fiber for stretchable woven or knitted fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester conjugate fiber which has rich bulkiness, is useful for a stretchable woven or knitted fabric, and forms the stretchable woven or knitted fabric having a new soft touch. SOLUTION: This polyester conjugate fiber is obtained by combining two kinds of polyesters having different intrinsic viscosities, respectively, into a side-by-side type where the joined surface of both the polyesters is curved in the cross section of the conjugate fiber. The conjugate fiber has a fiber Young's modulus of <=40 g/D and a crimp percent of >=30% and satisfies the following inequality: 0.05<=de/cd<=0.80, wherein c is a cross point between the fiber outer periphery of the high viscosity side polyester and a straight line X which passes through the center of a line ab binding two contact points a, b between the joined surface and the outer periphery of the conjugated fiber and crosses the line ab; d is a cross point between the joined surface and the straight line X; and e is a cross point between the line cd and the line ab; de/cd is the ratio of the length of the line de to the length of the line cd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester composite fiber for stretchable woven or knitted fabric which has a bulkiness and an unprecedented soft texture.

[0002]

2. Description of the Related Art In order to obtain a woven or knitted fabric having a stretching function, it is well known that a latent crimpable conjugate fiber in which two kinds of polyesters having different intrinsic viscosities are joined in a side-by-side type. When the latently crimpable conjugate fiber is subjected to a crimp development process 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 a stretch property, the three-dimensional crimped form of the yarn is required. And the crimping performance greatly affects the stretching performance when made into a fabric.

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 formed into a fiber has been increased. To improve operability,
Efforts have been made to straighten the joining surface of both polyesters in the fiber cross section, and various proposals have been made for these composite fibers.

For example, when the intrinsic viscosity difference between two types of polyester is large, the discharged yarn is bent during melt spinning. Further, when the intrinsic viscosity difference is further increased, the bending is excessively advanced, and the yarn adheres to the spinneret to cause cutting,
Spinning cannot be performed stably. Therefore, in a die in which polymers having different viscosities are discharged from a pair of discharge holes to form a side-by-side type conjugate fiber, each inclination formed by a pair of discharge holes with respect to a direction orthogonal to the die surface. Melt spinneret with controlled angle and distance between a pair of discharge holes (Japanese Patent Publication No. 61-60163)
Has been proposed.

[0005] When spinning is performed using the melt spinning die,
The joint surface of the two polyesters in the fiber cross section is straight. In this case, the spinning operability is good even if the intrinsic viscosity difference between the two types of polyesters is large, but since the joining surface of the two types of polyesters is linear, the three-dimensional crimp form of the developed crimp is small, Since a very large amount of crimps are developed per unit length, there is a problem that single yarns are stuck into each other, resulting in a flat texture lacking in bulkiness when formed into a woven or knitted fabric.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and, when knitted or woven, produces a stretchable woven or knitted fabric which is rich in bulkiness and has an unprecedented soft feel. An object of the present invention is to provide a polyester composite fiber.

[0007]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, the joint surface shape of both polyesters in the cross section of the fiber is curved within a specific range, By setting the Young's modulus of the strip within a specific range, it is possible to obtain a polyester composite fiber that can simultaneously impart bulkiness, unprecedented soft feeling, and stretchability to a fabric obtained by knitting and weaving. And found the present invention.

[0008] That is, the present invention provides a method for producing a polymer having different intrinsic viscosities.
Is a fiber in which two types of polyesters are combined in a side-by-side type, and the joining surface shape of both polyesters in the fiber cross section is curved, and a line segment ab connecting two contact points a and b between the joining surface and the outer periphery of the fiber When the intersection between the straight line X passing through the center of the line and perpendicular to the line segment ab and the outer periphery of the high-viscosity polyester is c, the intersection with the joining surface is d, and the intersection between the line cd and the line ab is e. The ratio de / cd of the length of the line segment de to the line segment cd satisfies the following formula (1), and the Young's modulus of the yarn is 40 g / D or less and the crimping ratio is 30% or more. A gist of the present invention is a polyester composite fiber for stretchable woven or knitted fabric. 0.05 ≦ de / cd ≦ 0.80 (1)

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail.

[0010] The conjugate fiber of the present invention has a different intrinsic viscosity.
It is necessary that the types of polyesters are fibers bonded to each other in a side-by-side type, and that the bonding surface shape of the two types of polyesters in the fiber cross section is curved. If the joining surface of the two types of polyester in the fiber cross section is linear, the crimp of the crimp developed by the shrinkage treatment becomes 3%.
Since the dimensional crimp shape is reduced and crimps are extremely generated per unit length, the single yarns are stuck. For this reason, the bulkiness of the woven or knitted fabric is reduced.

FIG. 1 is a cross-sectional view showing one embodiment of the conjugate fiber of the present invention. In FIG. 1, a line segment a connecting two contact points a and b between the joining surface of both polyesters and the outer periphery of the fiber.
The point of intersection between the straight line X passing through the center of b and perpendicular to the line segment ab and the outer periphery of the high-viscosity polyester fiber is c, the point of intersection with the joining surface is d, and the point of intersection between the line segment cd and the line segment ab is e. I do. In the conjugate fiber of the present invention, the ratio of the length of the line segment de to the line segment cd (hereinafter, de / cd) is set to 0.05 as in the above formula (1).
It is necessary to set it to 0.80. When this ratio is less than 0.05, the joining surface of both polyesters in the fiber cross section becomes linear, and the bulkiness of the woven or knitted product becomes low. On the other hand, when this ratio exceeds 0.80, the three-dimensional crimp morphology of the crimp developed by the shrinkage treatment becomes large.
In order to exceed 80, it is necessary to increase the difference in intrinsic viscosity between both polyesters, so that the discharge yarn is bent and adheres to the die surface during melt spinning, so that the yarn is cut. There is a problem that stable spinning cannot be performed.

The conjugate fiber of the present invention must have a Young's modulus of the yarn of 40 g / D or less. If the Young's modulus of the yarn is greater than 40 g / D, the texture of the woven or knitted fabric becomes hard and lacks a soft feeling. The method for setting the Young's modulus to 40 g / D or less is not particularly limited, but for example, a method in which the yarn is made of polyester having a relatively flexible structure is preferable. Among them, polytrimethylene terephthalate (hereinafter abbreviated as PTT) having excellent stretchability, dimensional stability, and light resistance is preferable.

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, Aromatic dicarboxylic acid components such as naphthalenedicarboxylic acid, aliphatic dicarboxylic acid components such as adipic acid, sebacic acid and azelaic acid;
Hydroxybenzoic acid, hydroxycarboxylic acid components such as ε-caprolactone, ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 2,
A diol component such as an ethylene oxide adduct of 2-bis {4- (β-hydroxy) phenyl} propane is exemplified.

Further, the conjugate fiber of the present invention needs to have a crimp ratio of 30% or more when the yarn is subjected to shrinkage treatment with boiling water. If the crimp rate is lower than 30%, the woven / knitted fabric obtained from this fiber has poor stretchability, and is not suitable for stretchable woven / knitted fabric. As a method for adjusting the crimp ratio to 30% or more, a method for adjusting the intrinsic viscosity difference between both polyesters is preferable. In order to increase the crimp rate of the conjugate fiber to 30% or more, polyester having an intrinsic viscosity of 0.6 to 1.10 on the low intrinsic viscosity side and 0.7 to 1.0% on the high intrinsic viscosity side are used.
It is preferable to use a polyester having an intrinsic viscosity of 1.30 and combine them so that the intrinsic viscosity difference between both polyesters is 0.1 or more.

In the conjugate fiber of the present invention, a matting agent such as titanium oxide, an antioxidant such as a hindered phenol compound, an ultraviolet absorber, etc. Light stabilizers, pigments, flame retardants, antibacterial agents, conductivity-imparting agents and the like may be added.

Next, an example of a method for producing the conjugate fiber of the present invention will be described. First, using a composite spinning device, two types of polyesters having different intrinsic viscosities are melted and weighed in separate weighing holes, merged to form a side-by-side type at the back of the spinneret, and the same at a spinning temperature of 240 to 290 ° C. After discharging from the discharge hole and cooling the spun yarn, oil agent is applied to
It is taken up at a speed of 000 to 4000 m / min and wound up. Next, drawing heat treatment is performed using a drawing twister to obtain the conjugate fiber of the present invention.

[0017]

EXAMPLES Next, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. In addition, the measuring method and the evaluation method in an Example are as follows. (1) Intrinsic viscosity [η] Measured at a temperature of 25 ° C. using an equal mixture of phenol and ethane tetrachloride as a solvent. (2) Crimp Ratio The obtained multifilament multifilament was wrapped around 1.125.
5 times with a measuring machine of m
A load of g / D is left for 30 minutes. Next, the sample is subjected to boiling water treatment for 30 minutes while the load is applied, and the treated sample is dried for 30 minutes. 1/500 g / dry sample
Apply a load of D and measure the length A. Then, 1/50
Remove the load of 0 g / D, apply a load of 1/20 g / D, measure the length B, and calculate by the following formula. Crimp rate (%) = [(BA) / B] × 100 (3) Evaluation of spinning operability Evaluation was made based on the number of cuts when spinning was performed with 16 weights for 24 hours. And 0 times: ○, 1-2 times: △, 3 times or more: × (4) Evaluation of stretchability and feeling Use of a denier of 50 denier / 24 filament polyethylene terephthalate (hereinafter abbreviated as PET) as the warp yarn. After weaving in a plain weave structure using the composite fiber obtained as the weft, and scouring the greige fabric,
Treated for 0 minutes and then air-dried,
Sensory evaluation was performed by human panelists. The evaluation was performed by the number of people who judged that the film had a stretchable, bulky and soft feel when pulled in the weft direction, and that the ○ and △ criteria were acceptable. 9 or more: ○, 7 to 8: △, 6 or less: × (5) Comprehensive Evaluation Considering each of the above evaluation items, comprehensively evaluate with ○, △, ×, and pass ○ and △ as acceptance criteria And

Example 1 0.4% by weight of titanium oxide and an intrinsic viscosity of 1.01
0.4% by weight of PTT (A) on the high viscosity side and titanium oxide
The PTT (B) containing the low viscosity side PTT (B) having an intrinsic viscosity of 0.78 was melted, and PTT (A) having a fiber cross-section from the same spinneret having 24 holes and a round cross-section having a hole diameter of 0.6 mm (A) The ejection ratio was adjusted so that the volume ratio of B) was 1: 1 and spinning was performed at a spinning temperature of 260 ° C.

Next, after the spun yarn is cooled and solidified by an air stream, 0.7% by weight of an oil agent is applied, and the yarn is divided into two parts.
The yarn was taken off at a speed of 800 m / min to obtain a 82.5 denier side-by-side semi-undrawn yarn. The discharge amount at this time was adjusted so that the fineness after stretching was 50 denier. Next, the obtained semi-unstretched yarn was heated at 70 ° C. for 1.6 hours.
After drawing 5 times, heat treatment was performed on a hot plate at 160 ° C to obtain a composite fiber of 50 denier / 12 filaments.

Examples 2-3, Comparative Examples 1-2 In order to change the de / cd in the cross section of the fiber, Table 1 was used.
A conjugate fiber was produced in the same manner as in Example 1 except that the intrinsic viscosity of PTT (B) was changed as shown in (1).

Example 4, Comparative Example 3 In order to change de / cd, an ethylene oxide adduct of 2,2-bis {4- (β-hydroxy) phenyl} propane was used as the third component in PTT (A). Example 4 is 5
Mol%, Comparative Example 3 was copolymerized at 2 mol%, and an intrinsic viscosity difference as shown in Table 1 was added to PTT (B).
A composite fiber multifilament was produced in the same manner as in Example 1.

Comparative Example 4 Containing 0.4% by weight of titanium oxide and having an intrinsic viscosity of 0.67
0.4% by weight of high viscosity PET (A) and titanium oxide
PET (A) having a fiber cross-section from the same spinneret having a low-viscosity PTT (B) having an intrinsic viscosity of 0.46 and having a round cross-section having a diameter of 0.8 mm and 24 holes, respectively. The ejection ratio was adjusted so that the volume ratio of B) became 1: 1 and spinning was performed at a spinning temperature of 295 ° C.

Next, after the spun yarn is cooled and solidified by an air stream, 0.7% by weight of an oil agent is applied, and the yarn is divided into two parts to obtain three parts.
The yarn was taken off at a speed of 300 m / min to obtain a 75-denier side-by-side semi-undrawn yarn. The discharge amount at this time was adjusted so that the fineness after stretching was 50 denier. Further, the obtained semi-unstretched yarn was stretched 1.5 times at 70 ° C., and then heat-treated on a hot plate at 150 ° C. to obtain a composite fiber of 50 denier / 12 filaments. Table 1 also shows the evaluation results of the composite fiber multifilaments obtained in Examples 1 to 4 and Comparative Examples 1 to 4.

[0024]

[Table 1]

As is clear from Table 1, the composite fiber multifilaments obtained in Examples 1 to 4 have few cut yarns at the time of spinning, and the woven fabric after heat treatment in which these composite fiber multifilaments are arranged on the weft is not shown. It had a bulky and soft texture with stretchability in the weft direction. Further, 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, and the correlation with the sensory evaluation of the fabric is very large. Met.

On the other hand, in Comparative Example 1, since the difference in intrinsic viscosity between both polyesters was too large, the discharged yarn was bent and attached to the die surface during melt spinning, and spinning was impossible. In Comparative Example 2, since the de / cd was too small, the three-dimensional crimped form of the crimp was small, the woven fabric lacked bulkiness, and the crimp rate was a low value. Next, in Comparative Example 3, PT
The crimping ratio was an appropriate value because the third component was copolymerized with T (A), but the crimped form was small because de / cd was too small, and the woven fabric lacked bulkiness. I was Furthermore, in Comparative Example 4, the texture of the woven fabric was hard because PET was used, and a woven fabric having a soft feeling was not obtained. Also, the Young's modulus was a value higher than 40 g / D.

[0027]

According to the present invention, there is provided a polyester composite fiber for a stretchable woven or knitted fabric which, when knitted or woven, has a bulky property and a stretchable woven or knitted fabric having an unprecedented soft feel.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of the polyester composite fiber for stretchable woven or knitted fabric of the present invention.

[Explanation of symbols]

a Contact point between both polyester bonding surfaces and fiber periphery. b Point of contact between both polyester bonding surfaces and fiber periphery. X A straight line passing through the center of the line segment ab and orthogonal to the line segment ab. c Intersection between the straight line X and the outer circumference of the high-viscosity polyester fiber. d Intersection between the straight line X and the joining surface of both polyesters. e Intersection between line segment ab and straight line X.

Claims (2)

[Claims] 1. A fiber in which two kinds of polyesters having different intrinsic viscosities are compounded in a side-by-side type with each other, and a joining surface shape of both polyesters in a cross section of the fiber is curved. The intersection point between the straight line X passing through the center of the line segment ab connecting the contact points a and b and orthogonal to the line segment ab and the outer periphery of the high-viscosity polyester fiber is c, the intersection point with the joining surface is d, and the line segment cd and line Assuming that the intersection point with the segment ab is e, the length ratio de / cd between the line segment de and the line segment cd satisfies the following expression (1), and the Young's modulus of the yarn is 40 g / D.
Hereinafter, a polyester composite fiber for a stretchable woven or knitted fabric, having a crimp rate of 30% or more. 0.05 ≦ de / cd ≦ 0.80 (1) 2. The polyester composite fiber for stretchable woven or knitted fabric according to claim 1, wherein the two kinds of polyesters are polytrimethylene terephthalates having a repeating unit of trimethylene terephthalate of 85% or more.