JPS6170012A - Polyester conjugated yarn - Google Patents

Abstract

PURPOSE:The titled yarn providing spun yarn having high hat shrinkage factor and improved stretchabiltiy, obtained by conjugating eccentrically a polyester having a specific copolymer compoent, consisting essentially of ethylene terephthalate, with polyethylene terephthalate. CONSTITUTION:(A) A copolymer polyester consisting essentially of a an ethylene terephthalate unit, obtained by copolymerizing the ethylene terephthalate unit with 3-6mol% metal sulfonate group-containing structural unit, eccentially conjugated with (B) polyethylene terephathalate or a copolymer polyester consisting essentially of an ethylene terephthalate unit different from the component A, to give the aimed yarn having the dry heat shrinkage factor S170 at 170 deg.C and the dry heat shrinkage factor S120 at 120 deg.C satisfying the relationships shown by the formulas S170>=5S20, 35>=X170>=15, respectively. The conjugated state of the yarn is preferably side by side type.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a polyester composite material having a high heat shrinkage rate and excellent crimp potential suitable for producing stretchable spun yarn or stretchable flexible nonwoven fabric. It concerns fibers.

(Prior art and its problems) Polyester fiber has good mechanical properties and thermal stability.

Due to its excellent washability, it is currently used in a wide range of applications. among them.

BACKGROUND ART Fibers with high elasticity and flexibility 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 mix or knit yarns made by coating rubber or spandex (polyurethane) fibers with spun yarn or the like. Fibers 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.

As another method, a method is known in which synthetic fibers having high heat shrinkability are spun into yarn and then subjected to relaxation heat treatment. However, even with this method, the shrinkage ability may not be able to overcome the convergence resistance due to the twisting of the spun yarn, or even if the shrinkage ability is maintained, the shrinkage ability is significantly reduced due to the heat treatment to stop the twisting of the spun yarn. At present, it has not yet been possible to provide a woven or knitted fabric with shrinkage properties.

In addition, nonwoven fabrics used as padding for sports clothing are required to have elasticity and flexibility, but methods to impart flexibility include using fibers with a fineness of . It has been known. In addition, the use of composite spiral crimp fibers has been proposed as a method of imparting stretchability, but in order to impart sufficient stretchability to nonwoven fabrics, the fiber density must be increased to strengthen the conjugation of the fibers. It is necessary to have a large number of crimps (strong (desirably a spiral crimp with 22 crimps/2.54 cm or more)).

However, it is not only difficult to produce raw cotton with such a large number of strong I shrinkages in the raw cotton manufacturing process, but even if it were possible, such raw cotton has neps and undefibrated areas during the carding process. It is inevitable that this will occur. Therefore, a method has been adopted in which the web is made into a relatively coarse one-fold raw cotton web and then subjected to a relaxing heat treatment to shrink the fibers and make spiral crimps visible. - It is necessary to increase the fineness in order to increase the stress required to cause sufficient crimp contraction due to frictional restraint between the fibers, and usually 6 d (denier) or more is required. For these reasons, a fiber that satisfies both stretchability and flexibility has not yet been known.

(Object of the Invention) The present invention satisfies these requirements and provides a polyester suitable for obtaining spun yarns for woven and knitted fabrics with excellent elasticity and nonwoven fabrics for padded cotton with poor flexibility and elasticity. The purpose is to provide fibers.

(Structure of the Invention) The present invention achieves the above object, and the gist thereof is as follows.

A composite fiber in which two types of polyesters A and B are eccentrically joined, wherein A is a copolymerized polyester mainly composed of ethylene terephthalate units copolymerized with 3 to 6 mol% of structural units having metal salt sulfonate groups, and B is a copolymerized polyester mainly composed of ethylene terephthalate units. A polyester composite fiber which is a copolymerized polyester mainly composed of polyethylene terephthalate or ethylene terephthalate units different from A, and has a dry heat shrinkage rate satisfying the following formula.

Sl. ≧5S12°35≧Sat. ≧15 SIT. :170°C dry heat shrinkage rate (%) S12°: 12
Dry heat shrinkage rate (%) at 0°C In the present invention SP? . and S1□. means the shrinkage rate when the fiber is left in a relaxed state for 15 minutes in an atmosphere of 170°C and 120°C.

Polyester A in the present invention includes 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, 5-lithium sulfoisophthalic acid, 4-sodium sulfophthalic acid, 4-sodium sulfophthalate, 4-sodium sulfo-2, It is obtained by adding 3 to 6 mol % of an ester-forming compound having a metal salt sulfo-2-to group, such as 6-naphthalene dicarboxylic acid or an ester-forming derivative thereof, and copolymerizing it. (If necessary, a small amount of other components may be copolymerized.) Polyester B is preferably polyethylene terephthalate, but may also contain a small amount of copolymerization component.

The fiber of the present invention is a conjugate fiber in which polyesters A and B are eccentrically joined, and is a latent crimped fiber that develops a spiral kump when subjected to relaxation heat treatment. Although the composite form is not particularly limited, a side-high side type is preferable to a core-sheath type.

The copolymerization ratio of the structural unit having a metal salt sulfonate group in polyester A needs to be 3 to 6 mol%, and a height of 3 mol% is insufficient for crimp development, and 6 mol% If it exceeds this value, the melting point of the polyester and the strength of the fiber will decrease significantly, making it unsuitable for general clothing.

In addition, in order to obtain stretchable IT products and nonwoven fabrics, it is necessary that crimp shrinkage does not occur during the heat treatment and twisting heat treatment in the spinning process, and most of the crimp shrinkage occurs during the subsequent relaxing heat treatment. According to numerous experiments conducted by the present inventors, it is desirable that Sl? .

≧5s,. It turned out that it was necessary to satisfy the following.

Traditional high shrinkage polyester fibers are Sl,. is 15
% or more, and in high cases, it was possible to manufacture products with a value of more than 50%. However, such high shrinkage polyester fibers are S1! . Sat. ≧
It did not satisfy 5S+io.

Sl'l in polyester fibers. It is impossible to satisfy ≧53.2° with ordinary high shrinkage fibers, and it is necessary to use composite fibers that have crimp shrinkage ability.

Sat. must be large, and 15% or more is necessary, but if it exceeds 35%, the fiber density will increase too much due to shrinkage and flexibility will be insufficient, so 35≧S Iff.

It is necessary to satisfy ≧15.

Fibers with such shrinkage characteristics are determined by the intrinsic viscosity of polyesters A and B, and the copolymerization ratio of structural units having metal salt sulfonate groups in polyester A.

It can be obtained by appropriately selecting the composite ratio of both polyesters, the stretching heat treatment conditions after spinning, etc.

For example, polyester A is a polyethylene terephthalate copolymerized polyester in which a 5-sodium sulfoisophthalate (SIP) component is copolymerized.

When polyethylene terephthalate (homopolymer) is used as polyester B to produce a composite fiber with a composite ratio of 1:1, the SIP component of polyester A is 4 to 6 mol%.
When , the intrinsic viscosity of polyester A is 0.40 to 0.5
0. It is preferable that the intrinsic viscosity of polyester B is 0.50-0.80, the tension heat treatment temperature is about 145-170'C, and the SIP component of polyester A is 3-4
When expressed as mol%, the intrinsic viscosity of polyester is 0.45~
0.55. The intrinsic viscosity of polyester B is 0.45 to 0.
75, and the tension heat treatment temperature is preferably about 120 to 145°C.

(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.

(Examples) Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited thereto.

Note that the intrinsic viscosity is a value measured at 520° C. in a mixed solvent of equal weights of phenol and tetrachloroethane.

Examples 1-6. Comparative Examples 1 to 2 Side-by-side composite fibers with a composite weight ratio of 1:1 using polyethylene terephthalate copolymerized polyester copolymerized with 5.1 mol% of SIP component as polyester A and polyethylene terephthalate as polyester B, using the combinations shown in Table 1. was spun to obtain five types of undrawn yarns: A, 3, 2, and 5.

Table 1 (all other spinning conditions are constant, spinning temperature 2
90℃, number of spinneret holes: 344, take-up speed: 1150m1
The discharge amount was 204 g/min. ) These five types of undrawn yarns were subjected to drawing heat treatment under the conditions shown in Table 2, and nine cuts were made to obtain polyester staple fibers.

Table 2 (All other stretching conditions are constant, toe denier after stretching is 350,000 denier, stretching temperature is 70°C.

The cut length was 51 mm. ) Example 7 Polyester B was a polyethylene terephthalate-based copolymerized polyester obtained by copolymerizing 3.2 mol% of SIP component with an intrinsic viscosity of 0.536, and polyester B was a polyethylene terephthalate copolymer with an intrinsic viscosity of 0.553. Undrawn yarn was obtained by spinning in the same manner as in Examples 1 to 6. Next, the tension heat treatment temperature was set to 130°C, the stretching ratio was set to 2.6 times,
The polyester short fibers were otherwise drawn and heat treated and cut under the same conditions as in Examples 1 to 6 to obtain short polyester fibers.

Comparative Example 3 Polyester short fibers were obtained in the same manner as in Example 7, except that a polyethylene terephthalate copolymer polyester obtained by copolymerizing 2.5 mol % of an SIP component with an intrinsic viscosity of 0.536 was used as polyester A.

Comparative Example 4 Polyethylene terephthalate having an intrinsic viscosity of 0.687 was spun at a temperature of 290°C and a number of spinneret holes of 518. Pick up speed 800
m1 minute, discharge f! Spinning at 329 g/min, stretching temperature 70°C, stretching ratio 4.0 times, tension t, treatment temperature 1
The polyester short fibers were heat-treated by stretching at 45° C. and cut at a cut length of 51 mm to obtain short polyester fibers.

Table 3 shows the performance of the fibers obtained on each side.

Table 3 Next, the polyester short fibers obtained on each side are combined with Unitika Co., Ltd.'s low melting point polyester fiber "Melty" 2d.
A web was prepared by mixing 5% by weight of each of ×5111IOI and carding with a carding machine, and subjected to relaxation heat treatment in an atmosphere of 160° C. for 5 minutes to obtain a nonwoven fabric with a basis weight of 120 g/m after cooling.

Each nonwoven fabric was cut into a width of 5 cm, and the length Ll) at a load of 30g and the length Ll) at a load of 240g were measured, and the elongation rate of the nonwoven fabric was determined from a linear equation.

Lz L+ Nonwoven fabric elongation rate = -X 100 (%) The nonwoven fabric elongation rates measured as described above are shown in Table 4. In addition, the nonwoven fabric obtained using the fibers of the examples also had good flexibility.

In addition, the polyester staple fibers obtained on each side were each made into 100% spun yarn with a count of 30, and after being subjected to a twist-stopping heat treatment (100°C x 30 minutes), it was heated for 5 minutes in an atmosphere of 170'C. Relaxation heat treatment was performed.

Furthermore, Example 1.3. Polyester short fibers of Comparative Examples 3 and 4 and regular short fibers of polyethylene terephthalate 2 dx51mm (S + qo 2.8%)
A spun yarn was prepared by blending the yarns in a ratio of 1:1 and heat-treated.

The length of the spun yarn at a load of 0.15 g (La) and 3.5 g
The length (Lb) at +W work load was measured and the elongation rate of the spun yarn was determined from the 9th equation.

La Table 4 shows the elongation rates of the spinning system measured as described above.

Table 4 1t? 1llZi lj i 14 1 -
－１□□□－□－咄一郎□□□－□□” (Effect of the invention) As mentioned above, the fiber of the present invention has a moderately high heat shrinkage rate and excellent latent crimp ability. By using this material, it is possible to obtain extremely stretchable nonwoven fabrics and spun yarns (IUIII products), which greatly contributes to improving the performance of materials for sports clothing.

Claims (1)

[Claims] (1) A composite fiber in which two types of polyesters A and B are eccentrically joined, in which A is a copolymerized polyester mainly composed of ethylene terephthalate units, in which 3 to 6 mol% of structural units having metal salt sulfonate groups are copolymerized. A polyester composite fiber, wherein B is polyethylene terephthalate or a copolyester mainly composed of ethylene terephthalate units different from A, and the dry heat shrinkage rate of the composite fiber satisfies the following formula. S_1_7_0≧5S_1_2_0 35≧S_1_7_0≧15 S_1_7_0: Dry heat shrinkage rate at 170°C (%) S_1_2_0: Dry heat shrinkage rate at 120°C (%)