JP2000328378A - Stretchable composite false-twist yarn - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject false-twist yarn where the stretch performance of the side-by-side type conjugate yarn is exhibited through the force of constraint or heat set due to the weaving preparation, knitted fabric texture and dyeing finish process, etc., for the composite false-twist yarn and twisted yarn and the like, and the dyeability difference between the core yarn and the sheath yarn is reduced, also capable of giving high-grade spun-like fabrics free from soft feeling or rubbery feeling. SOLUTION: This stretchable composite false-twist yarn is a sheath-core type two-layer structural yarn with a sheath yarn B coiled in an alternately reverse fashion around a core yarn A; wherein the core yarn A is a side-by-side type drawn conjugate yarn 25-45% in elongation composed of a high-shrinkage polyethylene terephthalate copolymerized with 8-15 mol% of isophthalic acid and/or a bisphenol A compound and a low-shrinkage polyethylene terephthalate 0.36-0.47 in intrinsic viscosity [η]f (fiber intrinsic viscosity), and the sheath yarn B is a highly oriented undrawn polyester-based yarn 90-180% in elongation produced by spinning at a speed of 2,000-3,500 m/min.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stretchable composite false twisted yarn capable of creating a fabric having a high stretchability and a good feel and appearance.

[0002]

2. Description of the Related Art Conventionally, as methods for obtaining a spanized fabric having excellent stretchability, (1) a method using an elastic yarn such as urethane, and (2) a method using a false twisted crimped yarn having an increased crimping force. (3) A method utilizing a side-by-side type conjugate yarn is known.

[0003] Among them, the method (1) using an elastic yarn can provide an ultra-high stretchability of 30 to 200%, but is inferior in dyeing fastness, chemical resistance, heat setting property and the like, and has a low cost. Because of the problem of high elasticity, it is used mainly in applications requiring particularly high elasticity in fields such as swimwear, underwear, and sports.

The method (2) of using false twisted crimped yarn is widely used because of its low cost, but it has high bulkiness as well as elasticity due to random crimping of single fibers. I do. Since the feeling of having a high feeling of bulkiness and a feeling of rubbery feeling due to the high bulky feeling is basically unacceptable, improvement of the feeling is desired in many applications. Of course, as a countermeasure, restraint of bulkiness by twisting yarn or the like has been attempted, but the reduction in bulkiness accompanying this also causes a reduction in stretchability, so that it has not yet reached a satisfactory range.

Further, the method using the conjugate yarn of (3) generally has the same size of the single fiber crimp, so that the yarn is easily bundled in a spiral shape as a whole and the random disorder of the single fibers is small. However, there was a drawback that the flat yarn style lacked a sense of spanning.

In order to overcome the disadvantages described above, Japanese Patent Publication No. 55534/1990 discloses that a conjugate yarn obtained by compounding a homopolymer of polyethylene terephthalate having a different intrinsic viscosity in a side-by-side type is used as a core yarn. Japanese Patent Publication No. 62-49376 proposes to employ a conjugate yarn obtained by compounding polybutylene terephthalate and polyethylene terephthalate in a side-by-side type as a core yarn.

[0007] However, in the former, the core yarn itself has a low crimping force in hot water, and therefore, the crimping (stretchability) is overcome by overcoming the restraining force received from the fabric structure as well as the composite yarn structure. There is a disadvantage that it cannot be expressed. Further, the latter has a drawback that the dyeing fastness, the heat setting property, and the feeling are reduced because the core yarn is made of a different kind of polymer.

[0008] A disadvantage common to both is that it is inevitable that spots are generated due to a difference in dyeing between the sheath yarn and the sheath yarn.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a side-by-side type conjugate yarn which has an elasticity which is determined by the preparation force for weaving composite false twisted yarn and twisted yarn, the weaving and knitting structure, and the binding force and heat setting by the dyeing and finishing process. Stretching that gives a high-quality spanized fabric that has a uniform appearance and is free of a feeling of tingling and rubber, with the dyeing difference between core yarn and sheath yarn being reduced as much as possible. It is to provide a composite false twist yarn.

[0010]

According to the present invention, at least two kinds of polyester-based filament yarns are used, one of which is a core yarn, and the other is a sheath yarn around which the core yarn and the core yarn are partially overlapped. Core-sheath type double-layered yarn wound alternately in an inverted manner while being mixed and entangled, wherein the core yarn is copolymerized with isophthalic acid and / or a bisphenol A compound in an amount of 8 to 15 mol%, and is a highly shrinkable polyethylene. Terephthalate and [η] _f (fiber intrinsic viscosity) of 0.3
It is composed of a drawn yarn of a conjugate yarn having an elongation of 25 to 45%, in which 6 to 0.47 low shrinkage polyethylene terephthalate is compounded in a side-by-side type, while the sheath yarn is spun at a spin speed of 2000 to 3500 m / min. , Elongation 90 ~
A stretchable composite false twist yarn is provided, which is made of a 180% polyester highly oriented undrawn yarn.

Here, the background of the present invention will be described. First, it is better to use a conjugate yarn as the core yarn in order to secure a crimping (expansion) expression force against the above-described various binding forces and heat setting as the whole elastic composite false twist yarn. . However, even in that case, polyethylene terephthalate obtained by copolymerizing isophthalic acid and / or bisphenol A compound at 8 to 15 mol% as two kinds of polymers constituting the conjugate yarn, and [η] _f of 0.36 to 0.47 polyethylene terephthalate was bonded and combined in a side-by-side type, with an elongation of 25 to
It is essential to use 45% drawn yarn.

Further, in order to obtain an appearance free of spots and a high-quality feel with little fluttering and rubbery feeling, the above-mentioned conjugate yarn is used as a core yarn and has a thickness of 2000 to 3500 m / m.
It has been confirmed that it is useful to arrange a polyester-oriented highly oriented undrawn yarn having an elongation of 90 to 180% obtained at a spinning speed of min as a sheath yarn.

[0013]

FIG. 1 shows an example of a side view of a stretchable composite twisted yarn according to the present invention (hereinafter sometimes referred to as "composite false twisted yarn").

In the figure, A is a core yarn (conjugate yarn) mainly contributing to the expansion and contraction performance of the entire composite false twist yarn, and B is a sheath yarn (polyester type yarn) mainly contributing to the appearance, feeling and characteristics of the entire composite yarn. Highly oriented unstretched). Here, as a form of the composite false-twisted yarn, although not shown, the sheath yarn is wound around the core yarn in an alternately twisted shape, but a part of the filaments of both yarns is mixed and entangled. The mold has a two-layer structure.

What is important is that, as described above, the core yarn A is a highly shrinkable polyethylene terephthalate obtained by copolymerizing isophthalic acid and / or bisphenol A compound in an amount of 8 to 15 mol% based on the total acid components, and [η] _f is 0.36
Elongation of 25 to 0.47, low-shrinkage polyethylene terephthalate laminated and compounded side-by-side
This assumes a 45% stretched conjugate yarn.

The high shrinkage polybutylene terephthalate disclosed in the above-mentioned JP-B-62-49376 provides a high shrinkage force, but reduces the dyeing fastness, heat setting property, etc., and further has a Young's modulus of polyethylene terephthalate. There is a problem in practical use for general clothing, such as lowering the waist repulsion feeling due to considerably lowering than fibers. In contrast,
In the present invention, since the high shrinkage polyethylene terephthalate which satisfies the above-mentioned specific requirements is adopted, the conventional problems are solved.

In general, the higher the draw ratio of the core yarn A and the lower the elongation, the lower the [η] _f of the low shrinkage side polymer, and the higher the crimpability. However, the elongation is 2 from the aspect of the stability of the drawing process and the spinning process.
When the drawn yarn of 5 to 45% is used, when the false twisting is performed, the degree of the cross-sectional deformation of the single fiber becomes small as shown in FIG. 2- (1), which is effective in maintaining the crimping performance. . By the way,
FIG. 2- (2) shows an example of a cross-sectional deformation of polybutylene terephthalate (P) fiber disclosed in the above-mentioned Japanese Patent Publication No. 62-49376.

Further, in order to further enhance the stretchability of the composite false twisted yarn of the present invention, in addition to the above, the thicker the single fiber denier of the core yarn A, the larger the ratio (weight) of the core yarn A to the yarn.
The effect increases as the value increases. However, from the viewpoint of appearance and feeling of the product cloth, the single fiber denier is 3.0 to 3.0.
8.0 denier, the ratio of core yarn A: sheath yarn B is 3: 7 to 5:
A range of 5 is preferred.

Further, the fiber cross-sectional shape of the core yarn A is shown in FIG.
(1) When the hollow cross section is used as shown in FIGS. 3- (2) and (3), there is an advantage that the crimp rate and the shrinkage force are further increased even with the same denier. At this time, the position of the hollow portion H is adjusted as shown in FIG.
As shown in (3), when the polymer is disposed in the high shrinkage side polymer P ₁ , when the high shrinkage side polymer shrinks, the bending of the low shrink side polymer P ₂ is not inhibited, so that high crimping performance is obtained.
At the same time, even when subjected to bending or elongation deformation in false twisting or other handling, peeling of the joint interface between the two polymers is prevented. This hollow ratio tends to increase the crimping ratio and crimping force of the conjugate yarn as a whole, but if it is too large, it may be crushed by the twisting force during false twisting, so in general, it is generally About 1 to 10% is preferable.

Further, the hollow cross-section yarn has a feature that it has a finer and stronger surface unevenness effect than the solid cross-section yarn, and provides a variety of new appearance products.

On the other hand, the sheath yarn B is 2000-3500 m / m
It is obtained at a spinning speed of "in" and is composed of a polyester-based highly oriented undrawn yarn having an elongation of 90 to 180%. That is, the dyeability is higher than that of a normal drawn polyester yarn. In response to this, isophthalic acid and / or bisphenol A compound is used as the core yarn in the present invention, although it is a drawn yarn.
Is a conjugate yarn composed of a polyethylene terephthalate copolymerized at a ratio of .about.15 mol% and a low [η] _f polyethylene terephthalate having an [η] _f of 0.36 to 0.47 in a side-by-side type. Dyes deeper than drawn yarn. Therefore, the dyeing density of the core yarn and the sheath yarn is close to each other, and a uniform dyeing and appearance can be obtained.
In this regard, in the case of the aforementioned Japanese Patent Publication No. 2-55534,
When the core yarn is stretched to 45% or less for a conjugate yarn composed of polyethylene terephthalate having only the [η] _f difference of polyester, the yarn is light-dyed and the sheath yarn has an elongation of 90 to 180%. The difference in dyeing concentration from a highly oriented undrawn yarn is increased, and it becomes extremely difficult to obtain a uniform dyed appearance.

In order to provide the composite false twisted yarn of the present invention with a high-textured spanised cloth having a rebound, the single yarn denier of the core yarn is made thicker, the single fiber denier of the sheath yarn is made smaller, and then the sheath yarn is further made. It is necessary to arrange around the core thread. As described above, in order to make the core yarn exhibit high shrinkage performance, the single fiber denier is set to be thick, so that the single yarn denier of the sheath yarn is 3.5 denier or less here. What is necessary is to make it fine.

Of course, the value of 3.5 denier itself cannot be generally regarded as fine denier, but in the present invention, a so-called highly oriented undrawn yarn having a lower molecular orientation than that of a drawn yarn is used. But you can get enough soft touch. Further, since the core yarn is a drawn yarn having an elongation of 25 to 45%, and the sheath yarn has an elongation of 90 to 180%, the core yarn and the sheath yarn due to the difference in elongation during false twisting. And a yarn length difference occurs in the range of approximately 15 to 30%, and a span-like feeling is obtained.

Here, by changing the false twisting temperature, the crimping ratio of the core yarn and the sheath yarn can be adjusted, and the crimping ratio changes depending on conditions such as the heater length and the processing speed. When the temperature is set to about 110 ° C. or more and 160 ° C. or less, the crimp rate of the sheath yarn becomes lower than the crimp rate of the core yarn, and the feeling of a feeling of rubbing and a rubbery feeling is greatly improved while having the stretch performance. .

Finally, an example of a production process of the stretchable composite false twist yarn according to the present invention will be described with reference to FIG.
The conjugate yarn (core yarn A) and the highly oriented undrawn yarn (sheath yarn B), which have already been described, are unwound from their respective packages, and the first supply roller 1 and the second supply roller 3 In the meantime, the air is introduced into the air entangled nozzle 3 in a relaxed state of a fixed length or about 1 to 3%, and subjected to a blending / entanglement process. Next, the obtained entangled yarn is a heater 4, a false twist device 5,
After being subjected to false twisting while passing through the take-out roller 6, it reaches the winding device 7.

[0026]

[Embodiment] Each evaluation item in the following example complies with the following definition.

[0027] - crimp; a load of 0.3 mg / d in yarn, left to dry 1 day after treatment with boiling water for 20 minutes crimp-expression measures yarn length L _0. Then 0.2g / d
Heavy loads measured yarn length L ₁ after 2 minutes multiplied by, calculating the shrinkage wound by the following formula. Crimp rate = [(L ₁ −L ₀ ) / L ₁ ] × 100 (%)

Stretch rate (ST) A test piece having a size of 5 cm × 20 cm is applied with an initial load of 20 g using a tensile tester equipped with an automatic recording device, and the interval between the test pieces is 10 c.
m, and the tensile speed is 30 cm / m.
After stretching with a constant load of 1.5 kg in, immediately return to the original position at the same speed and draw a load-elongation curve. here,
ST is an extension distance of Lcm just before returning to the original position at the same speed immediately after stretching with the above 1.5 kg constant load.
(Up to 0.01 cm), it is expressed by the following equation. ST = [(L-10) / 10] × 100 (%)

Elongation recovery rate (EL) In the load-elongation curve obtained at the time of measuring the above-mentioned stretch rate, after elongating under a constant load of 1.5 kg, immediately after returning to the original position at the same speed, the residual elongation was measured. Rcm (0.0
EL is expressed by the following equation. EL = [(LR) / L] × 100 (%)

Example 1 A polyethylene terephthalate obtained by copolymerizing 10% by mole of isophthalic acid and a polyethylene terephthalate having an [η] _f of 0.43 were mixed at a weight ratio of 1:
A 50 denier / 12 filament, elongation 35%, boiling water shrinkage obtained by stretching and heat-treating a so-called side-by-side type conjugate undrawn yarn spun by laminating side-by-side into a shape as shown in FIG. Rate 14
%, And a drawn yarn (core yarn A) having a hollow ratio of 3% was prepared.

On the other hand, 80 denier, 36 filaments, elongation 123 obtained by spinning polyethylene terephthalate having an [η] _f of 0.62 at a spinning speed of 3000 m / min.
A highly oriented undrawn yarn (sheath yarn B) having a% boiling water shrinkage of 42% was prepared.

The two yarns are aligned and supplied to the first supply roller 1 in FIG. 4, and then the yarn is relaxed by 2% between the roller 1 and the second supply roller 3 while the air entanglement nozzle is in a state of being relaxed. 2 to give 53 confounds per meter,
Subsequently, a so-called composite false twisting process is performed between the second supply roller 3 and the take-out roller 6 in a fixed length state through the heater 4 and the false twisting tool 5, and then wound by the winding device 7 as a composite false twisted yarn cheese. Was.

At this time, the heater temperature was 130 ° C., the heater length was 1.5 m, the number of false twists was 2500 times / m, and the take-out roller speed was 180 m / min.

The obtained composite false twist was 133 denier, 4
8 filaments, crimp rate 24%, boiling water shrinkage rate 4.2%,
The crimp rate of the core yarn was 60%, and the crimp rate of the sheath yarn was 30%. Further, in a state where the sheath yarn B was partially entangled and relaxed around the core yarn A, the S-twisted portion, the non-twisted portion, and the Z-twisted portion were wound and conjugated while being irregularly formed.

Next, 1800 per meter is applied to the yarn.
Twisted and steam-set at 80 ° C for 20 minutes to produce tricotine fabric with a warp density of 276 yarns / whale and a weft yarn density of 145 yarns / whale.
Set-Alkali weight loss-Dyeing-Set finishing was applied. Here, relax temperature is higher than normal 120
By giving a strong twisting effect at a temperature of ° C., crimping of the conjugate yarn was well exhibited, and particularly high stretchability was exhibited.

The thus obtained woven fabric has a warp density of 381 yarns / whale and a weft yarn density of 182 yarns / whale, and has a good stretchability of 19% in the warp direction and 22% in the weft direction. The stretch recovery rate was good at 90% or more in both the longitudinal and transverse directions. In addition, the feeling is also low because the crimp rate of the sheath yarn is low, and there is little feeling of flapping as seen in conventional false twisted yarn, but there is still a feeling of swelling,
And it had a high-grade feel with a waist rebound. Furthermore, the appearance was leveled because the dyeing densities of the core yarn and the sheath yarn were close to each other, and the dyeing fastness was at a level without practical problems while showing high deep color. In particular, those dyed in black were suitable as materials for black formal having excellent wearing feeling.

On the other hand, 60% per meter
0 twists, warp density 186 / whale, weft density 13
When the Venetian fabric was tested with 0 / whale and dyed under the same conditions as for the trichotin fabric described above, it was surprisingly found that the fabric was a strong twist fabric despite the 600 twists. A fine grained appearance with fine irregularities was obtained. Furthermore, the stretchability was 20% in the warp direction and 27% in the weft direction, and it was a novel woven fabric.

Comparative Example 1 [η] _f is 0.64 and 0.4
3 in a weight ratio of 1: 1.
-50 denier, 12 denier, obtained by subjecting a well-known side-by-side type conjugate undrawn yarn, which has been spun by laminating side by side to the shape shown in (1),
Filament, elongation 36%, stretched yarn a having a boiling water shrinkage of 15%, and highly denatured unstretched yarn B of 80 denier and 36 filaments used in Example 1 were brought together under the same conditions as in Example 1. Thus, a composite false twist yarn was obtained.

The composite false twisted yarn has 132 denier, 48 filaments, a crimp rate of 18%, a boiling water shrinkage rate of 3.6%, a core thread crimp rate of 48%, and a sheath thread crimp rate of 28%, and has almost a yarn form. It was similar to the stretchable composite false twist yarn of Example 1.

Next, the composite false twisted yarn was subjected to a twist-set-weaving-dyeing process under the same conditions as in Example 1 to obtain a warp density of 336 yarn / whale and a weft yarn density of 184 yarn / wool. Was low, the stretch ratio was as low as 12% in the warp direction and 15% in the weft direction, and the stretch recovery rate was also low. In addition, both the feeling and the crimping rate of the core and sheath were low, so that the swelling feeling and waist rebound were low, making it impossible as a stretchable material.

Further, the appearance of the core yarn is considerably lighter than that of the sheath yarn. It was of low quality, such as being seen.

On the other hand, a Venetian fabric was prepared under the same conditions as in Example 1 by twisting the yarn 600 times per meter, and a fine and sharp grainless appearance similar to the fabric obtained in Example 1 was obtained. Did not appear, but only rough and loose irregularities. The difference from Example 1 is mainly in the shrinkage ratio of the woven fabric in the relaxing step and the dyeing step during dyeing. The composite false twist yarn of the present invention has a strong crimp developing power of the conjugate yarn as the core yarn. There is a feature that the shrinkage ratio is larger than in the case of Comparative Example 1. Further, when the conjugate yarn used in Example 1 was immersed in boiling water in a free state to develop crimps, the spiral crimp was finer than in the case of the conjugate yarn used in Comparative Example 1, and between the single fibers. It is considered that a slight variation in the shape in the yarn length direction is observed, and this causes a slight variation in the torsional torque at the time of the occurrence of crimp, and it is considered that the fabric has a graining effect.

[0043]

According to the present invention, a stretchable spanished cloth having excellent appearance and texture is obtained at a low cost. As a result, not only can the swimwear, underwear and sportswear be used,
Inexpensive and high-quality fabrics can be provided for other fields requiring elasticity.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of a stretchable composite false twist yarn according to the present invention.

FIG. 2 is a side view showing a cross-sectional deformation of a stretchable composite false twist yarn according to the present invention and a core yarn in a conventional example.

FIG. 3 is a cross-sectional view showing an example of a raw yarn arranged as a core yarn of the stretchable composite false twist yarn according to the present invention.

FIG. 4 is a schematic diagram showing a production process of a stretchable composite false twist yarn according to the present invention.

[Explanation of symbols]

A core yarn B sheath yarn H hollow portion P ₁ higher-shrinking polymer P ₂ low shrinkage polymer

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[Procedure amendment]

[Submission date] June 7, 1999 (1999.6.7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

[0013]

FIG. 1 shows a stretchable composite according to the present invention.
False twisting yarn is shown an example of a side form (hereinafter, may be referred to as "composite false twist yarn").

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

Further, in order to further enhance the stretchability of the composite false twisted yarn of the present invention, in addition to the above, the thicker the single fiber denier of the core yarn A, the larger the ratio (weight) of the core yarn A to the yarn.
The effect increases as the number increases . However, from the viewpoint of appearance and feeling of the product cloth, the single fiber denier is 3.0 to 3.0.
8.0 denier, the ratio of core yarn A: sheath yarn B is 3: 7 to 5:
A range of 5 is preferred.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

Of course, the value of 3.5 denier itself cannot be generally regarded as fine denier, but in the present invention, a so-called highly oriented undrawn yarn having a lower molecular orientation than a drawn yarn is used. But enough soft touch can be obtained. Further, since the core yarn is a drawn yarn having an elongation of 25 to 45%, and the sheath yarn has an elongation of 90 to 180%, the core yarn and the sheath yarn due to the difference in elongation during false twisting. And a yarn length difference occurs in the range of approximately 15 to 30%, and a span-like feeling is obtained.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0025

[Correction method] Change

[Correction contents]

Finally , with reference to FIG. 4, an example of a production process of the stretchable composite false twist yarn according to the present invention will be described.
The conjugate yarn (core yarn A) and the highly oriented undrawn yarn (sheath yarn B), which have already been described, are unwound from their respective packages, and the first supply roller 1 and the second supply roller 3 In the meantime, the air is introduced into the air entangled nozzle 3 in a relaxed state of a fixed length or about 1 to 3%, and subjected to a blending / entanglement process. Next, the obtained entangled yarn is a heater 4, a false twist device 5,
After being subjected to false twisting while passing through the take-out roller 6, it reaches the winding device 7.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction contents]

Stretch rate (ST) A test piece having a size of 5 cm × 20 cm is applied with an initial load of 20 g using a tensile tester equipped with an automatic recording device, and the interval between the test pieces is 10 c.
m, and the tensile speed is 30 cm / m.
After extended up to 1.5kg constant load in in, back to the original position immediately at the same speed, load - draw elongation curve. here,
ST, after extended until the above 1.5kg constant force, just before returning to the original position immediately at the same speed, Lcm extension distance
(Up to 0.01 cm), it is expressed by the following equation. ST = [ L / 10] × 100 (%)

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0029

[Correction method] Change

[Correction contents]

[0029], elongation recovery rate (EL) load was obtained at the time of measurement of the stretch rate - in the expansion curve, after extended up to 1.5kg constant load, at the time of return to the original position immediately at the same speed, an initial load of 20g When the residual elongation under load is Rcm (up to 0.01 cm), EL
Is represented by the following equation. EL = [(LR) / L] × 100 (%)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4L036 MA05 MA17 MA19 MA24 MA26 PA01 PA05 PA46 RA04 RA25 UA02 4L041 AA07 BA02 BA05 BA09 BA22 BA33 BA42 BC05 BC17 BC20 BD12 BD14 BD20 CA06 CA12 DD01 DD10 DD15 EE15

Claims (5)

[Claims] 1. A filament comprising at least two kinds of polyester filament yarns, one of which is a core yarn and the other filament yarn is a sheath yarn and is alternately inverted while being partially mixed and entangled with the core yarn. Core-sheath type 2 wound in a shape
In the layered yarn, the core yarn is isophthalic acid and / or bisphenol A
A highly shrinkable polyethylene terephthalate obtained by copolymerizing the compound in an amount of 8 to 15 mol%, and [η] _f (fiber intrinsic viscosity) of 0.1
Elongation of 25 to 45%, in which low shrinkage polyethylene terephthalate of 36 to 0.47 is compounded in a side-by-side type.
And a sheath yarn comprising a highly oriented polyester-oriented undrawn yarn having an elongation of 90 to 180% spun at a spinning speed of 2000 to 3500 m / min. False twisted yarn. 2. The total denier of the core yarn and the total denier of the sheath yarn are in the range of 3: 7 to 5: 5 by weight ratio, and the single fiber denier of the core yarn is 3.0 to 8.0 denier, and the sheath. The stretchable composite false twist yarn according to claim 1, wherein the single fiber denier of the yarn is 3.5 denier or less. 3. The stretchable composite false twist yarn according to claim 1, wherein the core yarn is a hollow cross-section yarn. 4. The stretchable composite false twist yarn according to claim 3, wherein the hollow portion of the hollow cross-section yarn is located mainly in the region of the high shrinkage polyethylene terephthalate of the side-by-side type composite yarn. 5. The stretchable composite false twist yarn according to claim 1, wherein the crimp rate of the core yarn is larger than that of the sheath yarn.