JP2000239931A - Combined filament yarn of core-sheath type conjugate fiber which can be fibrillated, with components with different shrinkage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide combined filament yarn of core-sheath type composite with the components of different shrinkage, good in spinnability, causing fibrils when treated with an alkali to reduce weight, and giving cloth by, e.g. knitting or weaving, which is free of pilling and wear-caused blanching. SOLUTION: This combined filament yarn is composed of two groups of fibers having different boiling water shrinkage, with the sheath of the single yarn which constitutes each of the higher-shrinkage yarn (filament yarn X) and lower-shrinkage yarn (filament yarn Y) being composed of two types of polyester components different from each other in solubility in alkali. The yarn has an overall boiling water shrinkage of 40% or less, difference between the filament yarns X and Y in boiling water shrinkage is 5 to 25%, and one the sheath-constituting polyester components which is sparingly soluble in alkali (component A) satisfies the conditions of (a) intrinsic viscosity of 0.6 or more before treatment with moist heat, and (b) intrinsic viscosity sustained at 70 to 92% of the initial level after treatment with moist heat (boiling water) for 30 min.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a core-sheath type composite heterogeneous shrinkable yarn having a sheath portion composed of two kinds of polyester components having different alkali solubility, and which is subjected to an alkali weight reduction treatment. The present invention relates to a core-sheath type composite differentially shrinkable mixed fiber which elutes a readily soluble component and becomes a fibrillated differentially shrinkable mixed yarn.

[0002]

2. Description of the Related Art Various fibrillated fibers have been proposed to improve the feeling of fabrics such as polyester woven and knitted fabrics. Among them, the sheath portion of the core-sheath type composite fiber has different solubility.
It is well known that fibrils are formed by subjecting a composite fiber composed of components to an alkali weight reduction treatment.

[0003] JP-A-2-51673 discloses a core-sheath type composite fiber for producing fibrils by subjecting it to an alkali weight reduction treatment.
Japanese Patent Application Laid-Open No. 61-75873 discloses a composite fiber in which nylon and polyester are disposed in a sheath portion as two components having different solubility.
In the publication, a composite fiber in which an alkali-soluble polyester and a normal polyester are disposed in a sheath portion is described. Among them, in consideration of the spinnability, the cost, the color tone of the obtained fiber, and the like, a combination of the alkali-soluble polyester and the ordinary polyester is preferable.

[0004] However, in the case of a composite fiber in which an alkali-soluble polyester and ordinary polyester are simply disposed in a sheath portion, when the woven or knitted fabric is fibrillated by alkali reduction treatment, pilling or abrasion whitening in the fibril portion is conspicuous. As a result, there is a problem that the use for clothing is limited.

[0005] To solve this problem, Japanese Patent Laid-Open Publication No.
No. 38 proposes a conjugate fiber using a low-viscosity polyester having an intrinsic viscosity [η] of 0.48 to 0.60 as a component of a poorly soluble alkali constituting a sheath portion. However,
When this composite fiber is subjected to an alkali weight reduction treatment to cause fibrillation, the abrasion whitening of the resulting fabric made of the fibrillated fiber is improved, but the strength of the composite fiber itself is low, so that both spinning and drawing are performed. There has been a problem that yarn breakage is likely to occur and the yarn operability is poor.

[0006] In order to improve the feel to a more swelling feeling, it is generally effective to use a different shrinkage mixed fiber, but since the fibrillated fiber has low strength, other fibers (for example, fibrillated fiber) are used. It is indispensable to mix fibers with highly shrinkable yarns), and it is difficult to obtain different shrinkage mixed fibers between fibril fibers in terms of operability and characteristics.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems, has good spinnability, develops fibrils when subjected to an alkali weight reduction treatment, and provides a fabric obtained by knitting and weaving. It is an object of the present invention to provide a fibrilable core-sheath composite heterogeneous shrinkable yarn that does not cause pilling or wear whitening and has a soft touch and a rich swelling feeling. .

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that the sheath portion is a core-sheath type conjugate fiber composed of two kinds of polyesters having different alkali solubility, and By using a polyester whose viscosity is reduced by wet heat treatment as a polyester component that is hardly soluble in alkali, it has a certain degree of strength at the raw yarn stage, and has good spinning operability and processability, but the fibril is reduced in the weight reduction step. It has been found that in a wet heat treatment step such as dyeing, the strength of the fibril portion is reduced by lowering the viscosity and the problem of pilling or abrasion whitening is solved, and the present invention has been achieved.

That is, according to the present invention, a high shrinkage yarn (yarn X) and a low shrinkage yarn (yarn Y) are composed of different shrinkage mixed fiber yarns composed of two kinds of fibers having different boiling water shrinkage rates. The sheath portion of each single fiber is a yarn composed of two types of polyester components having different alkali solubility, the boiling water shrinkage of the whole yarn is 40% or less, and the boiling water shrinkage of yarn X and yarn Y The difference between
25% of the polyester constituting the sheath,
It is a gist of a core-sheath type composite heterogeneous shrinkable fiber which can be fibrillated, wherein the alkali-insoluble polyester component (component A) satisfies the following requirements. (A) The intrinsic viscosity before wet heat treatment is 0.6 or more. (B) The intrinsic viscosity retention before and after wet heat treatment (30 minutes in boiling water) is 70 to 92%.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The fibrilable core-sheath type hetero-shrinkable mixed fiber yarn of the present invention is composed of a highly shrinkable yarn (yarn X) and a low shrinkage yarn (yarn Y), both of which have a sheath component having an alkali-soluble B component. It is composed of a polyester of the component A which is hardly soluble in alkali, and the component A is a polyester whose intrinsic viscosity is reduced by wet heat treatment. By subjecting this conjugate fiber to an alkali weight reduction treatment, the B component is dissolved and removed, and fine fibrils are formed. In addition, fibrillation means that the B component is completely dissolved and removed, and the sheath portion is only the A component, or the B component is partially left, and the A components are partially separated through the B component. It means that it is in a joined form.

[0012] The polyester of the component A must have an intrinsic viscosity before wet heat treatment of 0.6 or more. If the intrinsic viscosity of the component A is less than 0.6, yarn breakage or the like is likely to occur at the time of spinning, the operability is deteriorated, and the strength of the obtained yarn is reduced.
The upper limit of the intrinsic viscosity before the wet heat treatment is preferably set to about 0.9. Incidentally, the limiting viscosity in the present invention,
Using an equal mixture of phenol and ethane tetrachloride as a solvent,
This is a value measured at 20 ° C.

Further, the polyester of component A must have an intrinsic viscosity retention rate after the wet heat treatment (30 minutes in boiling water) with respect to the intrinsic viscosity before the wet heat treatment (30 minutes in boiling water) of 70 to 92%. . If the intrinsic viscosity retention before and after the wet heat treatment is less than 70%, the strength of the fibers after the wet heat treatment is too much reduced, and a fabric having sufficient strength cannot be obtained. Further, if the intrinsic viscosity retention ratio before and after the wet heat treatment exceeds 92%, when pilling occurs, the pilling does not easily fall off, so that the fabric made of this fiber is pilling or abrasion whitening.

The intrinsic viscosity after the wet heat treatment is not particularly limited, but should be 0.55 or more in order to prevent the strength of the yarn after the wet heat treatment such as dyeing from becoming too low. Is preferred.

Since the monofilament constituting the hetero-shrinkage mixed fiber of the present invention is a conjugate fiber, it is difficult to take out only the component A and measure the intrinsic viscosity retention before and after the wet heat treatment. Therefore, regarding the intrinsic viscosity retention rate, spinning and stretching using a polyester containing only the A component, and using the obtained yarn,
It is a value obtained by performing a wet heat treatment as follows.

The drawn yarn containing only the component A is treated in boiling water for 30 minutes, and the intrinsic viscosity [η] ₀ of the drawn yarn before the wet heat treatment and the intrinsic viscosity [η] ₁ of the drawn yarn before and after the wet heat treatment are obtained. It is calculated by: Intrinsic viscosity retention (%) = ([η] ₁ / [η] ₀ ) × 10
0 (%)

The polyester of the component A is such that the acid component is composed of terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid and the like. Naphthalenedicarboxylic acids are preferred, and those obtained by copolymerizing a small amount of aliphatic dicarboxylic acids such as adipic acid, sebacic acid and azelaic acid with these aromatic dicarboxylic acids may be used.

On the other hand, as the glycol component, ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanediol, neopentyl glycol and the like can be used. It is preferable to use glycol and 1,4-butanediol as main components.

Further, in order to make the polyester of the component A have the intrinsic viscosity of the above-mentioned polymer or the intrinsic viscosity retention rate before the wet heat treatment, the polyester contains 0.5 to 1.5 mol% of a phosphorus compound based on all the acid components of the polyester. Are preferred. Phosphorus compounds include phosphoric acid and tri-n-phosphate
Butyl, dimethyl phosphate, diethyl phosphate, dibutyl phosphate and the like can be employed.
The phosphoric acid compound may be added at any stage before the polycondensation reaction between the acid component and the glycol component is started.

On the other hand, the polyester of the component B has high alkali solubility, but preferably has a solubility of at least 5 times that of the polyester of the component A.
Those having a solubility of 15 times or more are more preferable. In addition,
Here, the solubility is a comparison based on a weight loss rate when treated in a 2% by weight aqueous sodium hydroxide solution at 100 ° C. for 30 minutes.

The polyester of the component B comprises the same acid component and glycol component as the polyester of the component A and has a sulfonate group, for example, 5-sodium sulfoisophthalic acid, 5-lithium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid or having a molecular weight of 5
Copolymerized polyesters obtained by copolymerizing 00 to 5000 polyethylene glycol are exemplified.

The polymer constituting the core is not particularly limited as long as it has a fiber-forming ability and has a lower alkali solubility than the polyester of component B.
It has the same solubility as the polyester of the component A, and it is preferable to use PET from the viewpoint of mechanical properties.

The above-mentioned polyesters of the A and B components in the sheath portion and the polymer in the core portion may be added with a pigment, a matting agent, a fluorescent whitening agent, an ultraviolet absorber during polycondensation or melt spinning.
An antioxidant, an antistatic agent, and an ether bond inhibitor such as an organic amine and an organic carboxylic acid amide may be added as required.

Further, the fibrilable core-sheath type heterogeneous shrinkable fiber of the present invention has a shape in which the A component and the B component constituting the sheath portion are alternately joined in 16 or more layers, and the weight ratio is (A / B) is preferably from 1/1 to 10/1.

That is, the component B has a shape in which the component A exists as an independent phase in the component A. In particular, as shown in FIG. It is preferable that (2) is joined in a shape not surrounding the other component B (3), and both components are joined continuously in a layered shape along the longitudinal direction of the filament. By adopting such a shape, the spinning and drawing operability is improved, and the defects of the product are reduced.

Such a conjugate fiber having a multilayer structure can be obtained by blending the A component and the B component during spinning, but industrially, a method using a static mixer is preferred. The relationship between the number of layers and the number of mixer stages (n) in the multilayer structure of the sheath portion is as follows, where the number of mixer stages is (n).
The maximum number of layers is 2 ⁿ . Therefore, the number of layers can be changed by changing the number of stages (n) of the mixer. For example, if the number of mixer stages (n) is 6, the number of layers can be up to 64, and if (n) is 7, the number of layers can be up to 128. Finer fibrils can be formed by increasing the number of layers, and thicker fibrils can be formed by decreasing the number of layers, but the upper limit is preferably about 64.

Further, the weight ratio (A / B) of the component A and the component B constituting the sheath portion is set to 1/1 to 10/1, and more preferably to 2 /
It is preferably 1 to 5/1. When the ratio of the component B is higher than that of the component A, the components elute to the fibrils during the weight reduction of the alkali, and the remaining fibrils are liable to fall off in the subsequent processing. On the other hand, when the ratio of the component A is higher than 10/1, the amount of the components to be eluted is too small, and it becomes difficult to produce fine fibrils.

The alkali weight reduction treatment for forming fibrils on the core-sheath composite heterogeneously shrinkable mixed fiber of the present invention includes a treatment using an aqueous alkali solution or the like. Examples of the alkali used include lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate and the like. Among them, it is preferable to use sodium hydroxide which is inexpensive and has a large elution ability. The concentration of such an alkali compound varies depending on the kind of the alkali compound, treatment conditions and the like, but is usually 0.1 to 20% by weight, preferably 1 to 10% by weight.

The above-mentioned alkali weight reduction treatment is carried out in the following manner:
Or it may be applied in any state of woven or knitted fabric, usually 60 to
In a hot bath at 100 ° C or in steam at 100-150 ° C,
It is performed in a range of minutes to 1 hour. The weight loss rate is 40% by weight or less, preferably 10 to 30% by weight. When the weight loss rate exceeds 40% by weight, the polyester of the component A also tends to be dissolved, and fibrils are easily lost. Also, the weight loss rate
When it is less than 10% by weight, it is difficult to sufficiently fibrillate. Further, the bonding surface may be separated by mechanical refraction such as false twisting before or after this treatment.

The core-sheath type composite heterogeneous shrinkable yarn of the present invention is a fibril in which fibrils are formed in the sheath by the component B being completely or partially eluted by such weight reduction treatment. It becomes a synthetic shrinkage mixed fiber.

In the alkali weight reduction treatment, the B component of all the filaments need not be reduced uniformly and to the same extent, and the weight reduction rate may be different depending on the filament. That is, in the filament, there is a mixture in which the component B is completely dissolved and removed to form a fibril of the component A alone, or a filament which is partially fibrillated. As a result, in these filaments, the variation in single-fiber fineness between the filaments after fibrillation occurs, whereby a soft feeling, a swelling feeling, and a warm feeling are exhibited in a natural fiber-like. Since it is a hetero-shrinkage mixed fiber, the soft feeling and the swelling feeling are further enhanced.

Next, the boiling water shrinkage ratio of the different shrinkage mixed fiber yarn of the present invention must be 40% or less for the whole yarn. Boiling water shrinkage
If it exceeds 40%, the coarseness is emphasized and the texture lacks a soft feeling. Further, the difference between the boiling water shrinkage ratios of the yarn X and the yarn Y needs to be in the range of 5 to 25%. The difference in boiling water shrinkage
If it exceeds 25%, the loop due to the difference in heat shrinkage becomes too large at the time of heat treatment, and the workability at the time of weaving or at the preparation stage deteriorates. The difference in boiling water shrinkage is 5%.
If it is less than 30, the paper-like feeling is obtained, and the fabric cannot express a rich swelling feeling.

Here, the boiling water shrinkage ratio is determined by extracting a different shrinkage mixed fiber yarn from a package, dividing it into a high shrinkage yarn and a low shrinkage yarn, and performing skewing with a scaler to obtain 1/30 ( g /
Measure the yarn length L ₀ under the load of D), then immerse the yarn in boiling water under no load for 30 minutes to shrink the yarn, air-dry, and
1/30 the yarn length L ₁ under a load of (g / d) was measured, and is calculated by the following equation. Boiling water shrinkage (%) = [(L ₀ −L ₁ ) / L ₀ ] × 100

The cross-sectional shape of the core-sheath type conjugate fiber constituting the hetero-shrinkage mixed fiber of the present invention may be any shape such as a round cross-section, a triangular cross-section, a Y cross-section, a U cross-section, and a flat cross-section. . The shapes of the core and the sheath may be the same or different. The thickness may be uneven in the length direction by changing the stretching conditions.

In the core-sheath type composite different shrinkage mixed yarn of the present invention, the method of mixing the high shrinkage yarn (yarn X) and the low shrinkage yarn (yarn Y) was obtained from separate spinnerets. A method of blending the material in a post-processing stage such as stretching or processing is also conceivable, but the process becomes complicated and the number of processes increases, which is not preferable in terms of cost. Therefore, the fiber blending method is the yarn A and the yarn B
And spinning with the same spinneret, giving a difference in heat shrinkage at the stretching stage, and blending.

The spinning speed for obtaining the core-sheath type composite heterogeneously shrinkable mixed yarn of the present invention is preferably from 2800 to 4500 m / min. An undrawn yarn wound at a spinning speed of less than 2800 m / min is liable to change over time and must be drawn quickly. On the other hand, when spinning at a speed exceeding 4500 m / min, the yarn is damaged during spinning, and the operability of spinning is likely to be reduced.

FIG. 2 is a schematic process drawing showing an example of a method of giving a difference in heat shrinkability to the core-sheath composite undrawn yarn in the drawing stage and blending the fibers. In FIG. 2, an undrawn yarn 4 for a high shrinkage yarn is drawn between a heating roller 7 and a drawing roller 9 via a guide 6 to become a high shrinkage yarn (yarn X). on the other hand,
The unstretched yarn 5 for a low shrinkage yarn is stretched while being heated by a plate heater 8 between a heating roller 7 and a stretching roller 9 via a guide 6 to become a low shrinkage yarn (yarn Y). The yarn X and the yarn Y are drawn together by the guide 6 and wound up as a target core-sheath type composite heterogeneously shrinkable mixed yarn on the stretched pan 10.

[0038]

Next, the present invention will be described in detail with reference to examples. In addition, the measurement and evaluation in an Example were performed as follows. (A) Intrinsic viscosity [η] Measured by the method described above. (B) Retention of intrinsic viscosity after wet heat treatment The drawn yarn was measured and calculated by the above method. (C) Strength Using the yarn after alkali reduction treatment, use Orientic Tensilon Universal Tester RTC-1210 type to measure the sample length.
The measurement was performed at 500 mm and a pulling speed of 500 mm / min. (D) Friction whitening resistance The obtained fibers were combined into three yarns and knitted into a tube, and a 1% by weight aqueous sodium hydroxide solution was used at a bath ratio of 1: 100 and a treatment temperature of 98 ° C.
Miketon PET Black RN-SF (Disperse dye manufactured by Mitsui Toatsu Chemicals) 4% owf, Dianix Black FB-FS (Disperse dye manufactured by Mitsubishi Chemical) 12% owf, Kayaoryl BlackR-ED (basic dye manufactured by Nippon Kayaku) 8% owf, acetic acid 0.2cc /
High-pressure dyeing was carried out in a dye bath containing 1 at a bath ratio of 1: 100, at a temperature of 125 ° C. for 1 hour.

Thereafter, the measurement was performed 500 times and 1000 times with a load of 500 g using a universal wear tester manufactured by Shimadzu Corporation.

The evaluation was evaluated as ○ when the whitening due to abrasion was slight and inconspicuous to the naked eye, Δ when the whitening due to abrasion was slightly conspicuous, and X when the whitening due to abrasion was noticeable. (E) Anti-pilling properties The obtained fibers were plied into three yarns, knitted into a tube, subjected to the same alkali weight reduction treatment and dyeing as in (d), and then treated with an ICI pilling tester manufactured by Daiei Kagaku Seiki Seisaku-sho, Ltd. The time was measured and a series was assigned.

Grade 4 or higher was rated as 、, 2nd or 3rd grade as Δ, and 1st or lower grade as ×. (F) Fibril generation amount The obtained fibers were plied into three yarns, knitted in a tube, subjected to the same alkali reduction treatment as in (d), and the degree of generation of microfibrils existing on the surface was observed with a scanning electron microscope.

In the evaluation, ○ indicates that the amount of generated fine fibrils was large, and X indicates that the amount of generated fine fibrils was small. (G) Boiling water shrinkage ratio Measured and calculated by the above method. (H) Operability Evaluated by the number of yarn breaks during spinning and stretching.糸 indicates that the number of yarn breaks per 24 hours was 1 or less, and X indicates that the number was more than 1 time. (I) Evaluation of hand After sizing the different shrinkage blended yarn into warp, weaving the weft in a plain weave structure using the same yarn as the weft, relax the scouring machine in hot water at 98 ° C. After weight reduction of alkali by weight, it was washed with water, dyed and dried. About this woven fabric, ten panelists consisting of weaving, knitting and dyeing technicians were allowed to evaluate the swelling feeling and soft feeling of the fabric by touch. A sample with excellent evaluation was evaluated as ○, and a sample with poor texture was evaluated as ×.

REFERENCE EXAMPLE 1 [Polyester of component A (poorly soluble in alkali)] This is a polyester comprising terephthalic acid (TPA) and ethylene glycol (EG), and has a phosphoric acid content before the polycondensation reaction.
0.85 mol% was added. Thereafter, 2 × 10 ^-4 mol of antimony trioxide was added to 1 mol of all acid components as a polycondensation catalyst to carry out polycondensation to obtain polyester A1. Next, A2 to A6 were obtained in the same manner as in A1, except that the type and content of the phosphorus compound were changed as shown in Table 1. Table 1 shows the intrinsic viscosities of these polyesters A1 to A6.
Shown in

These polyesters A1 to A6 were spun and drawn according to a conventional method to obtain a drawn yarn having a single yarn fineness of 1.5 denier, and the intrinsic viscosity retention was measured. Table 1 also shows the intrinsic viscosity retention rate and the intrinsic viscosity after the wet heat treatment. A3 is
Because the phosphoric acid content was too high, it gelled during polymerization and could not be spun.

[0045]

[Table 1]

[Polyester of Component B (Easily soluble in alkali)] A polyester comprising TPA and EG, wherein 5-sodium sulfoisophthalic acid is used in an amount of 2.5 mol% with respect to 1 mol of all the acid components constituting the polyester. And 15 × 10 ^-4 mol of sodium acetate were added to carry out polycondensation to obtain a polyester B. [Polymer in core part] Polymerization was carried out in the same manner as in Component A except that phosphoric acid was not added, to obtain a polyester having an intrinsic viscosity of 0.69.

Examples 1 to 7, Comparative Examples 1 to 4 Using the A and B components in the sheath portion and the polymer shown in Reference Example 1 in the core portion, a core-sheath composite differential shrinkage having a cross-sectional shape as shown in FIG. A mixed yarn was produced.

At this time, the spinning temperature was set to 295 by using a composite spinning apparatus so that the weight ratio of the core and the sheath became 1/1.
The melt spinning was performed at a temperature of 3500 m / min and a winding speed of 3500 m / min. Subsequently, the two wound undrawn yarns were drawn in the drawing step shown in FIG. 2 to obtain a 50D / 24F different shrinkage mixed fiber. At this time, the two undrawn yarns are drawn by a draw roller heater heated to 85 ° C. at a magnification of 1.3 times and a drawing speed of 730 m / min.
The yarn was set with a plate heater to obtain a low-shrinkage yarn, and the other yarn was subjected to a heat-shrinkable yarn without heat treatment, and the two yarns were aligned with a guide and wound up into a pirn. In addition, the value of the boiling water shrinkage rate was adjusted by variously changing the temperature of the heat plate.

The number of sheath layers, the polymer ratio of the sheath portion (component A / component B) of the obtained core-sheath type composite heterogeneous mixed fiber, the strength of the composite type heterogeneous mixed fiber after alkali reduction treatment, Table 2 also shows the evaluation results of the abrasion whitening resistance, the anti-pilling property, the amount of generated fibrils, the operability and the feeling.

[0050]

[Table 2]

As is evident from Table 2, the core-sheath type composite heterogeneous shrinkage yarns of Examples 1 to 7 have good operability at the time of production, and when these fibers are subjected to alkali reduction treatment. ,
Many fibrils are generated, and the obtained fabric has anti-pilling properties,
The friction whitening resistance and the feeling were further evaluated to be high.

On the other hand, in Comparative Example 1, component A had a high intrinsic viscosity retention before and after wet heat treatment. Therefore, when the knitted fabric made of the composite fiber obtained was subjected to alkali weight reduction treatment, pilling and friction whitening occurred. occured. In Comparative Example 2, since the intrinsic viscosity of the polymer at the time of spinning of the component A was too low, yarn breakage occurred during spinning and drawing, resulting in poor operability. Further, in Comparative Example 3, the difference in boiling water shrinkage between the high shrinkage yarn and the low shrinkage yarn was too large, and in Comparative Example 4, the difference in boiling water shrinkage between the high shrinkage yarn and the low shrinkage yarn was too small. The texture of the woven fabric obtained from the composite fibers was poor.

[0053]

The core-sheath type composite heterogeneous shrinkable yarn of the present invention has a sheath portion composed of a polyester having a low alkali solubility and having a reduced intrinsic viscosity by wet heat treatment and a polyester having a high alkali solubility. Therefore, spinning and stretchability can be obtained with good. And the core-sheath type composite heterogeneous shrinkage mixed yarn of the present invention is fibrillated by alkali weight reduction treatment,
In addition, since the viscosity of the fibril portion is reduced in a process such as dyeing, pilling and abrasion whitening hardly occur in a fabric made of this fiber. In addition, even after the alkali weight reduction treatment, the core remains without undergoing substantial fibrillation, so it has very good elasticity and stiffness, and because it is a hetero-shrink mixed fiber, it has a soft touch and richness It is possible to obtain a cloth having a swelling feeling.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a single fiber constituting a fibrilable core-sheath type composite heterogeneous shrinkable yarn of the present invention.

FIG. 2 is a schematic process diagram showing an example of a drawing machine for producing the fibrilable core-sheath type composite heterogeneous shrinkable fiber of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Core part 2 Alkali poorly soluble polyester (component A) 3 Alkali easily soluble polyester (component B)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) D06M 101: 32 F-term (Reference) 4L031 AA18 AB10 AB23 BA09 BA18 CA01 CA15 DA01 DA03 DA07 4L036 MA05 MA15 MA24 MA33 MA39 MA40 PA01 PA03 PA19 PA33 PA46 RA03 UA01 4L041 AA08 AA20 AA25 BA04 BA06 BA21 BA26 BB08 BC20 BD14 CA06 CA10 CA12 DD01 DD11 DD15 EE15 EE20

Claims (2)

[Claims] 1. In a different shrinkage mixed fiber comprising two kinds of fibers having different boiling water shrinkage rates, each single fiber constituting a high shrinkage yarn (yarn X) and a low shrinkage yarn (yarn Y) is used. The sheath portion is a yarn composed of two kinds of polyester components having different alkali solubility, and the shrinkage of boiling water of the whole yarn is 40% or less, and the yarn X
And the yarn Y have a difference in boiling water shrinkage of 5 to 25%, and
A fibrilable core-sheath type composite heterogeneous shrinkable yarn characterized in that, among the polyesters constituting the sheath portion, the alkali-insoluble polyester component (component A) satisfies the following requirements. (A) The intrinsic viscosity before wet heat treatment is 0.6 or more. (B) The intrinsic viscosity retention before and after wet heat treatment (30 minutes in boiling water) is 70 to 92%. 2. The fibrilable core-sheath composite heterogeneously shrinkable yarn according to claim 1, wherein the polyester of the component A contains a phosphorus compound in an amount of 0.5 to 1.5 mol% based on the total acid component.