JPS6278214A - Polyester conjugated yarn - Google Patents

Abstract

PURPOSE:To obtain the titled yarn causing neither nep nor unopened part in a carding process, by providing conjugated yarn having highly spiral crimp developing ability consisting of specific two polyesters with mechanical crimp having a specific number of crimps. CONSTITUTION:Polyester conjugated yarn wherein a copolymer polyester A comprising an ethylene terephthalate unit as a main component copolymerized with 3-6mol% constituent unit containing a metallic sulfonate group is eccentrically bonded to a copolymer polyester comprising polyethylene terephthalate or ethylene terephthalate unit as a main component, different from the copolymer polyester A. The polyester conjugated yarn has <=10% substantial heat shrinkage percentage by free shrinkage heat treatment at 170 deg.C, latently crimping ability to develop >=50 crimps/25mm spiral crimps and 8-15 crimps/25mm mechanical crimps. The polyester conjugated yarn is processed into spun yarn, woven and knitted goods or nonwoven fabrics and when subjected to relaxing heat treatment, it develops strong spiral crimps to give products having improved stretchability and elastic recovery.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a spun yarn with excellent elasticity and elastic recovery, or an excellent latent crimp ability suitable for obtaining a woven or knitted fabric or a nonwoven fabric for padded cotton. The present invention relates to a polyester composite fiber having a mechanically crimped structure.

(Conventional technology) 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 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.

As a method of imparting elasticity to woven and knitted fabrics, etc., it has been done to mix and knit yarns made by coating rubber or spandex fibers with spun yarn, etc., but rubber or spandex fibers 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, even with this method, it is not possible to achieve a 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 the heat treatment to prevent twisting of the spun yarn. However, at present, it has not been possible to provide a woven or knitted fabric with sufficient stretchability.

In addition, nonwoven fabrics used as padding for sports clothing are required to have elasticity and elastic recovery, and a method using composite fibers with spiral crimps has been proposed as a method of imparting elasticity to nonwoven fabrics. . In order to impart sufficient stretchability to a nonwoven fabric, it is necessary to increase the fiber density, strengthen the conjugation between the fibers, and increase the number of crimps. It has also been attempted to obtain strong crimp by applying mechanical crimp to latent crimpable composite fibers and supplementing the spiral crimp of composite fibers with mechanical crimp (for example, Japanese Patent Laid-Open No. 52-53027 (see official bulletin).

However, in the raw cotton manufacturing process, it is not only difficult to produce raw cotton with such strong crimps, but even if it were possible, such raw cotton would have neps and undefinated parts during 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 relaxation heat treatment after forming it into a web using a carding machine. In this case, it is common to suppress the thermal history as much as possible in the raw cotton manufacturing process. As a result, heat shrinkage occurs at the same time as crimping occurs, resulting in problems such as a hard feel and only elasticity without durability.

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 a spun yarn, a woven or knitted fabric, or a nonwoven fabric for padding that does not generate neps or unopened fibers in the carding process and has excellent stretchability and elastic recovery. The technical problem is to provide polyester fibers suitable for obtaining polyester fibers.

(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 was found that this objective can be achieved by applying mechanical crimping of several numbers.
We have arrived at the present invention.

That is, 9 the present invention comprises a copolymerized polyester A mainly composed of ethylene terephthalate units, which is obtained by copolymerizing 3 to 6 mol% of structural units having a metal salt sulfonate group, and a copolymerized polyester B mainly composed of ethylene terephthalate units different from polyethylene terephthalate or A. Composite fibers joined eccentrically.

Free shrinkage heat treatment at 170°C resulted in an effective heat shrinkage rate of 1.
0% or less, has a latent crimp ability of 50/25 mm or more, and has 8 to 18 spiral crimp 7251)
The gist of the invention is a polyester composite fiber characterized by being mechanically crimped.

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 sulfonate group, such as 6-naphthalenedicarboxylic 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 composite fiber in which polyesters A and B are eccentrically joined, and is a latent crimpable fiber that develops spiral crimp through 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 needs to be 3 to 6 mol%, and if it is less than 3 mol%, the crimp development power is insufficient, so 6 mol% is required. If it exceeds the limit, 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 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 30/25 mm or more, preferably 40/25 mm.
It is necessary to have a spiral crimp of 1 or more, and for this purpose, it is necessary to have the ability to express spiral crimp of 50/25 or more in the raw cotton state.

In addition, if the shrinkage rate during heat treatment is large, the woven or knitted fabric or non-woven fabric becomes extremely hard and the durability of the stretchability becomes poor.
When subjected to free shrinkage heat treatment at 70°C, the effective heat shrinkage rate is 1.
It is necessary to keep it below 0%.

Fibers having such latent crimp ability and heat shrinkage rate are characterized by the intrinsic viscosity of polyesters A and B, the copolymerization ratio of structural units having metal salt sulfonate groups of polyester A, 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 S'IP component in the polyester is 4 to 6 mol%, the intrinsic viscosity of the polyester is 0.40 to 0.50°, the intrinsic viscosity of polyester B is 0.50 to 0.80, and the tension heat treatment temperature is It is preferable to set the temperature to about 145 to 170°C, and when the SIP component to the polyester is 3 to 4 mol%, the intrinsic viscosity of polyester A is set to 0.45 to 0.55. Polyester B
It is preferable that the intrinsic viscosity of is set to 0.45 to 0.75, and the tension heat treatment temperature is set to 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. Generally, the occurrence of neps and unopened fibers is closely related to the number of crimps and the form of crimps, and in the case of one machine crimping,
If the number of crimps is less than 8/25, unopened fibers are likely to occur.
, 18 pieces, 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, 5
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 0 pieces/25 mm or more.

As a method for applying mechanical crimp, a stuffing box type, a heating gear set, etc. can be adopted.

A stuffing box method is generally used to produce short fibers.

Note that the fibers of the present invention are matting agents and gloss improvers.

It may contain modifiers such as antistatic agents, flame retardants, and softening and smoothing agents, and its 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

In addition, since the fibers of the present invention are latent crimpable fibers that have been given a moderate degree of mechanical crimp, they do not generate neps or unfibrillated parts during the carding process, and can be used to fabricate spun yarns, woven or knitted fabrics, or non-woven fabrics. After that, a strong spiral crimp is developed by a relaxation heat treatment.

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] In a mixed solvent of equal weights of phenol and tetrachloroethane.

Measured at 20°C.

(2) Number of crimps measured by the method of JIS L-1015-7-12-1.

(3) Fineness Measured by the method of JIS L-1015-7-5-IA.

(4) Heat shrinkage rate Measured by the method of JIS L-1015-7-15 at a load of 300 mg per denier.

Examples 1-4. Comparative Examples 1 to 2 Polyethylene terephthalate copolymerized polyester copolymerized with 5.1 mol% of SIP component as polyester A, polyethylene terephthalate with [η) 0.687 as polyester B, and the combinations shown in Table 1 at composite weight ratios I2 by spinning 1:1 side-high side type composite fiber.
Three types of undrawn yarns, 2 (ro) and 3 (c), were obtained.

Table 1 (all other spinning conditions are constant, spinning temperature 2
90℃, number of spinneret holes: 344, take-up speed: 1) 50m/
The discharge amount was 204 g/min. ) These three types of undrawn yarns were subjected to drawing heat treatment under the conditions shown in Table 2, mechanically crimped using a stuffing box, and then cut to obtain short 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 5 As polyester A [η) Polyethylene terephthalate copolymerized polyester copolymerized with 362 mol% of SIP component of 0.536, as polyester B [η)
Using 0.553 polyethylene terephthalate, undrawn yarn was obtained by spinning in the same manner as in Examples 1 to 4. Next, stretching and tension heat 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. Short fibers were obtained.

Comparative Example 3 Short fibers were obtained in the same manner as in Example 5, except that a polyethylene terephthalate copolymer polyester obtained by copolymerizing 2.5 mol% of an STP component of Cη) 0.570 was used as the polyester A.

Comparative Example 4 Polyethylene terephthalate (Cη) 0.687 was spun at a temperature of 290°C and a spinneret with a number of holes of 518. Pick up speed 80
Spinning at 0 m/min, discharge rate 329 g/min, stretching temperature 0°C, stretching ratio 4.0 times, tension heat treatment temperature 145
The fibers were subjected to stretching heat treatment at 0.degree. C., mechanically crimped using a stuffing box, and then canted with a cut length of 51 mm to obtain short fibers.

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

Table 3 Next, the short fibers obtained on each side are the low melting point polyester fiber “Melty” manufactured by Unitika Co., Ltd. 2d×51m1
) 1 was blended in an opener at a rate of 15% by weight, and carded with a carding machine to create a web with a basis weight of 35 g/n.

Next, the web was heated for 50 seconds with a heated roll at a surface temperature of 1) 5°C, and then heated in an oven at 160°C for 50 seconds.
A nonwoven fabric was obtained by performing free shrink heat treatment for a minute.

The obtained nonwoven fabric was cut into a width of 25 mm, and the elongation and elastic recovery rate were determined using a constant speed extension type tensile testing machine at a sample length of 10 Chm and a tensile rate of 100 sn/min.

(B is the value of 80% of the elongation of the nonwoven fabric, and C is the elongation relative to the sample length before measurement after being stretched to the value of B, removing the load, and standing for 1 minute.) The measurement results are shown after heat treatment. It is shown in Table 4 along with the basis weight of the nonwoven fabric.

Table 4 Table 4 (Continued) In addition, each of the short fibers obtained in Example 1.2 and Comparative Example 3 was made into a 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 5 (Effects of the Invention) According to the present invention, a spun yarn, a woven or knitted fabric, or a nonwoven fabric for padding, which does not generate neps or unopened fiber parts in the carding process and has excellent stretchability and elastic recovery, is 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.1 The present invention greatly contributes to improving the performance of materials for sports clothing, in particular. .

Claims (1)

[Claims] (1) 3 to 6 structural units having metal salt sulfonate groups
A composite fiber in which a copolymerized polyester A mainly composed of ethylene terephthalate units copolymerized in mol% and a copolymerized polyester B mainly composed of polyethylene terephthalate or ethylene terephthalate units different from A are eccentrically joined,
Free shrinkage heat treatment at 170°C resulted in an effective heat shrinkage rate of 1.
0% or less, has a latent crimp ability to express 50 spiral crimp/25 mm or more, and 8 to 18 spiral crimp/25 mm
A polyester composite fiber characterized by being mechanically crimped.