JPH045769B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention has an excellent latent crimp ability suitable for obtaining spun yarns or woven or knitted fabrics or nonwoven fabrics for padding with excellent stretchability and elastic recovery properties, and is capable of being mechanically wound. This invention relates to short fibers made of compressed polyester composite fibers. (Conventional technology) Polyester fiber has mechanical properties, thermal stability,
Due to its excellent washability, it is currently used in a wide range of applications. among them,
BACKGROUND OF THE INVENTION Fibers with high stretchability and elastic recovery are required for woven and knitted fabrics such as sports clothing and nonwoven fabrics such as padded cotton for sports clothing due to requirements for functionality and fit. A method of imparting elasticity to woven or knitted fabrics is to use rubber or spandex (polyurethane) fibers mixed and knitted with spun yarn and other yarns. They have drawbacks such as being expensive, having too much stretchability making it difficult to control the fit, and rubber and spandex fibers having extremely low resistance to dyeing. Another known method is to use synthetic fibers with high heat shrinkability that are spun into yarn and then subjected to relaxation heat treatment. However, this method also fails to exhibit shrinkage ability that overcomes the convergence resistance due to the twisting of the spun yarn, and even if the shrinkage ability is maintained, the shrinkage ability is significantly reduced due to heat treatment to prevent twisting of the spun yarn. However, at present, it has not yet been possible to provide a woven or knitted fabric with sufficient stretchability. In addition, stretchability and elastic recovery are required for nonwoven fabrics used as padding for sports clothing, etc., and a method using composite fibers with spiral crimps has been proposed as a method of imparting stretchability to nonwoven fabrics. . In order to impart sufficient stretchability to a nonwoven fabric, it is necessary to increase the fiber density to strengthen the conjugation between the fibers, as well as to increase the number of crimps and make it strong. It has also been attempted to obtain a strong crimp by applying mechanical crimp to latent crimpable composite fibers and supplementing the spiral crimp of the composite fiber with mechanical crimp (for example, Japanese Patent Laid-Open No. 52-53027 (See public information). However, it is not only difficult to produce raw cotton with such many and strong crimps in the raw cotton manufacturing process, but even if it were possible, with such raw cotton, neps and unfibered parts are formed in the carding process. It is inevitable that this will occur. Therefore, it is desirable to create a spiral crimp by subjecting the web to a relaxing heat treatment after forming it into a web using a carding machine.In this case, however, it is common to suppress the thermal history as much as possible in the raw cotton manufacturing process. Therefore, there were problems such as spontaneous shrinkage occurring at the same time as crimping, resulting in a hard feel and poor elasticity. Further, when the raw cotton has spiral crimps, neps and unopened fiber portions are likely to occur during the carding process even if the crimps are relatively coarse. (Problems to be Solved by the Invention) The present invention provides spun yarns, woven and knitted fabrics, or padded cotton nonwoven fabrics that do not generate neps or unopened fibers during the carding process and have excellent stretchability and elastic recovery properties. The technical objective is to provide short polyester fibers suitable for (Means for Solving the Problems) As a result of intensive studies in order to solve the above problems, the present inventors have found that a composite fiber having a high spiral crimp ability made of two specific types of polyester has a specific crimp. It has been found that this object can be achieved by applying mechanical crimping to the fibers, and the present invention has been achieved. That is, the present invention provides short fibers consisting of composite fibers in which copolymerized polyester A mainly composed of ethylene terephthalate units and polyethylene terephthalate B, which are copolymerized with 3 to 6 mol% of structural units having metal salt sulfonate groups, are eccentrically joined. Atsushi, 170
Free shrinkage heat treatment at ℃ has an effective heat shrinkage rate of 10
% or less, has a latent crimp ability to express 50 spiral crimps/25 mm or less, and is characterized by being endowed with mechanical crimps of 8 to 18 crimps/25 mm. That is. Polyester A in the present invention includes 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, 5-lithium sulfoisophthalic acid, 4-lithium sulfoisophthalate, and
- Adding 3 to 6 mol% of an ester-forming compound having a metal salt sulfonate group such as sodium sulfophthalic acid, 4-sodium sulfophthalic acid, 4-sodium sulfo-2,6-naphthalene dicarboxylic acid, or an ester-forming derivative thereof, and copolymerizing it. It is obtained by
(If necessary, a small amount of other components may be copolymerized.) As the polyester B, polyester terephthalate (including those recognized as substantially polyethylene terephthalate) is used. The fiber of the present invention is a composite fiber in which polyesters A and B are eccentrically joined, and is a latent crimpable fiber that develops spiral crimp when subjected to relaxation heat treatment. Although the composite form is not particularly limited, the side-by-side type is preferable to the core-sheath type because it has a better ability to develop crimp. The copolymerization ratio of structural units having metal salt sulfonate groups in polyester A is 3 to 6.
If it is less than 3 mol%, crimp development power is insufficient, and if it exceeds 6 mol%, the melting point of the polyester and the strength of the fiber are significantly reduced, making it unsuitable for general clothing. . In addition, in order to obtain stretchable woven or knitted fabrics or non-woven fabrics, the number of fibers constituting the woven or knitted fabric or non-woven fabric when crimped is 30 pieces/25 mm or more, preferably 40 pieces/25 mm or more, in a spiral shape. It is necessary to have crimp, and for that purpose, the raw cotton must be 50
It is necessary to have the ability to develop spiral crimp of 25 mm or more. In addition, if the shrinkage rate during heat treatment is large, the woven or knitted fabric or non-woven fabric will become extremely hard, and the durability of its stretchability will be poor. It is necessary to ensure that the actual thermal shrinkage rate is 10% or less. Fibers with such latent crimp ability and heat shrinkage rate are determined by the intrinsic viscosity of polyesters A and B, the copolymerization ratio of polyester A and a structural unit having a metal salt sulfonate group, the composite ratio of both polyesters, after spinning, This can be obtained by appropriately selecting the tension heat treatment conditions during stretching. For example, when producing a composite fiber with a composite ratio of 1:1 using a polyethylene terephthalate copolymer polyester copolymerized with a 5-sodium sulfoisophthalate (SIP) component as polyester A and polyethylene terephthalate (homopolymer) as polyester B. , when the SIP component of polyester A is 4 to 6 mol%, the intrinsic viscosity of polyester A is 0.40 to
0.50, the intrinsic viscosity of polyester B is preferably 0.50 to 0.80, the tension heat treatment temperature is preferably about 145 to 170°C, and the SIP component of polyester A is 3 to 4.
When expressed as mol%, the intrinsic viscosity of polyester A is 0.45.
~0.55, the intrinsic viscosity of polyester B is 0.45~0.75
The tension heat treatment temperature is preferably about 120 to 145°C. In addition, it is necessary to use raw cotton that does not produce neps or unopened fibers during the carding process. In general, the occurrence of neps and unopened fibers is closely related to the number of crimps and the form of crimps.In the case of mechanical crimping, if the number of crimps is less than 8/25mm, unspread fibers are likely to occur; /If it exceeds 25 mm, neps are likely to occur. Furthermore, if spiral crimp occurs before the carding process, neps are likely to occur, resulting in poor web uniformity and web slippage. Therefore, 50 pieces/
It is preferable to impart mechanical crimps of 8 to 18 pieces/25 mm to a latent crimpable composite fiber having the ability to develop spiral crimps of 25 mm or more. As a method for imparting mechanical crimp, a stuffing box method, a heating gear method, etc. can be adopted, but the stuffing box method is generally adopted for producing staple fibers. In addition, the fiber of the present invention contains a matting agent, a gloss improver,
It may contain modifiers such as antistatic agents, flame retardants, softening and smoothing agents, and the cross-sectional shape is not limited to circular.
A triangular cross section or other irregularly shaped cross section may be used. (Function) The reason why the fiber of the present invention exhibits good latent crimp ability is not clear, but it is related to the fact that the polyester obtained by copolymerizing the structural unit having a metal salt sulfonate group of polyester A has a certain degree of crosslinked structure. It is assumed that. Furthermore, since the fibers of the present invention are latent crimpable fibers that have been given appropriate mechanical crimp, they do not generate neps or unwoven parts during the carding process, and can be used with spun yarn, woven or knitted fabrics, or non-woven fabrics. After that, it is subjected to relaxation heat treatment to develop strong spiral crimp.
This provides a spun yarn, woven or knitted fabric, or non-woven fabric that has high elasticity and high elastic recovery. (Example) Hereinafter, the present invention will be explained in detail with reference to Examples. In addition, the measuring method of characteristic values etc. in an Example is as follows. (1) Intrinsic viscosity [η] Measured at 20°C in a mixed solvent of equal weights of phenol and tetrachloroethane. (2) Number of crimp Measured by the method of JIS L-1015-7-12-1. (3) Weave Measured according to the method of JIS L-1015-7-5-1A. (4) Heat shrinkage rate Measured by the method of JIS L-1015-7-15 at a load of 300 mg per denier. Examples 1 to 4, Comparative Examples 1 to 2 Polyester A was a polyethylene terephthalate copolyester copolymerized with 5.1 mol% of the SIP component, polyester B was polyethylene terephthalate with [η] 0.687, and composites were prepared in the combinations shown in Table 1. Three types of undrawn yarns A, B, and C were obtained by spinning side-by-side composite fibers at a weight ratio of 1:1.

[Table] These three types of undrawn yarns were subjected to drawing heat treatment under the conditions shown in Table 2, mechanically crimped in a stuffing box, and then cut to obtain short fibers.

[Table] Example 5 SIP component of [η] 0.536 as polyester A
Using polyethylene terephthalate having [η] 0.553 as polyester B, a polyethylene terephthalate copolymerized polyester copolymerized with 3.2 mol %, undrawn yarn was obtained by spinning in the same manner as in Examples 1 to 4. Next, stretching and tension treatment were carried out under the same conditions as in Examples 1 to 4, except that the tension heat treatment temperature was 130°C and the stretching ratio was 2.6 times. Next, the fibers were mechanically crimped using a stuffing box and then cut to obtain short fibers. Comparative example 3 SIP component of [η] 0.570 as polyester A
Short fibers were obtained in the same manner as in Example 5, except that 2.5 mol % copolymerized polyethylene terephthalate copolyester was used. Comparative Example 4 Polyethylene terephthalate with [η] 0.687 was spun at a temperature of 290°C, the number of spinneret holes was 518, and the take-up speed was
Spinning at 800 m/min, discharge rate 329 g/min, then stretching temperature 70°C, stretching ratio 4.0 times, tension heat treatment temperature 145°C
The cut length was 51 mm after being subjected to stretching heat treatment under the conditions of
Short fibers were obtained by cutting in mm. Comparative Example 5 Polyester A was a polyethylene terephthalate copolymerized polyester having a copolymerization of 3.2 mol% of the SIP component [η] 0.461, and polyester B was a polyethylene terephthalate copolymerized polyester of 3.2 mol% of the SIP component [η] 0.395.
Using the polyethylene terephthalate copolymerized polyester of 20%, undrawn yarns were obtained by spinning in the same manner as in Examples 1 to 4. Next, the tension heat treatment temperature was 135℃,
After stretching and tension heat treatment were carried out at a stretching ratio of 2.8 times and the other conditions were the same as in Examples 1 to 4, mechanical crimp was applied using a stuffing box and cutting was performed to obtain short fibers. Table 3 shows the performance of the fibers obtained in each of the above examples.

[Table] Next, the short fibers obtained in each of the above examples were added to the low melting point polyester fiber “Meltei” manufactured by Unitika Co., Ltd.
Blend 2d x 51mm of cotton at a rate of 15% by weight with an opener, and curl it with a carding machine to make 35g/
A web with a basis weight of ^m2 was created. Next, the web is rolled with a heated roll with a surface temperature of 115℃.
A primary heat treatment was performed for 50 seconds, followed by a free shrink heat treatment for 5 minutes in an oven at 160°C to obtain a nonwoven fabric. The obtained nonwoven fabric was cut to a width of 25 mm, and the elongation and elastic recovery rate were determined using a constant speed extension type tensile tester at a sample length of 100 mm and a tensile speed of 100 mm/min. Elastic recovery rate = B - C / B × 100 (%) (B is the value of 80% of the elongation of the nonwoven fabric, C is the sample before measurement after being stretched to the value of B, removing the load, and leaving it for 1 minute. The measurement results are shown in Table 4 along with the basis weight of the nonwoven fabric after heat treatment.

[Table] In addition, the short fibers obtained in Examples 1 and 2 and Comparative Example 3 were each made into 100% spun yarn with a count of 20,
The elongation and elastic recovery rate were determined in the same manner as in the case of the nonwoven fabric described above. The results are shown in Table 5.

[Table] (Effects of the invention) According to the present invention, spun yarns, woven and knitted fabrics, or nonwoven fabrics for padding, which do not generate neps or unopened fibers in the carding process and have excellent stretchability and elastic recovery properties, can be produced. Polyester fibers suitable for obtaining are provided. By using the fibers of the present invention, spun yarns, woven or knitted fabrics, or non-woven fabrics with extremely excellent stretchability and elastic recovery properties can be obtained, and the present invention greatly contributes to improving the performance of materials for sports clothing in particular. .

Claims (1)

[Claims] 1 3 structural units having a metal salt sulfonate group
It is a short fiber consisting of a composite fiber in which copolymerized polyester A mainly composed of ethylene terephthalate units copolymerized with ~6 mol% and polyethylene terephthalate B is eccentrically joined, and the substantial heat shrinkage rate is Less than 10%, 50 pieces/25
A polyester composite fiber characterized by having a latent crimp ability to express spiral crimp of 8 to 18 pieces/25 mm and having mechanical crimp of 8 to 18 pieces/25 mm.