JP2006169649A - Cationic dye-dyeable polyester yarn and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cationic dye-dyeable polyester yarn which has sufficient stretchability and swollen touch. <P>SOLUTION: The cationic dye-dyeable polyester conjugated multifilament yarn. And the cationic dye-dyeable polyester conjugated multifilament yarn having thick-thin irregularity in the axial direction of the yarn, a thickest single filament diameter/thinnest single filament diameter ratio of 1.2 to 2.4 in an arbitrary diameter, and a strength of ≥2.0 cN/dtex is obtained by spinning a cationic dye-dyeable polyester polymer having a melt viscosity Via≥8.3×10<SP>2</SP>poise and a polyester polymer having a viscosity Vib≤8.0×10<SP>2</SP>poise [Via and Vib are the melt viscosities of the polymers A and B, respectively, at a temperature of 280°C and a shear rate of 2.43×10<SP>3</SP>(sec-1)] at a takeoff rate of ≤2,500 m/min on a heated roller in specific conditions. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a cationic dye-dyeable polyester composite fiber that gives stretchability and good swelling feeling when it is made into a woven or knitted fabric, and a method for producing the same.

  Conventionally, in Patent Document 1 and Patent Document 2, two types of thermoplastic polymers having different melt viscosities are made into bonded composite fiber yarns by composite spinning that discharges them from the same discharge hole, and spiral crimps are developed by heat treatment to produce a crimped stretch. In order to obtain high crimp, it is known to increase the difference in melt viscosity between the two types of thermoplastic polymers used, and by using highly shrinkable polyester as a high melt viscosity component. Polyester-based latently crimped composite fibers have been proposed, and it is known that fabrics made of these fibers will have a stretchable and deep color. However, the fiber has a spiral crimp, but is uniform in the longitudinal direction of the fiber, so that when the fabric is formed, it has a flat surface feeling and lacks bulkiness and swelling.

On the other hand, Patent Literature 3 and Patent Literature 4 have thick and thin fibers whose fineness changes in the longitudinal direction of the fiber as a method for improving the texture of the fiber product. Therefore, it is disclosed that the fabric obtained from the thick and fine fibers exhibits a unique texture. However, according to the fiber, it is partially mixed with different shrinkage, and the fabric obtained from the thick fiber has a feeling of swelling, but there is a problem that it is inferior in stretchability, and further improvement in functionality is required. Yes.
In order to deal with such problems, for example, as a means for imparting stretch properties to the fabric, there is a method using polyurethane-based elastic fibers, but this presents a problem that costs increase due to an increase in the number of steps.

Further, Patent Document 5 and Patent Document 6 disclose composite fiber yarns that exhibit stretch properties and a span-like texture or a thick slab-like appearance when made into a fabric. Because it has a fine slab-like appearance, it has a highly oriented part and a lowly oriented part that are localized in the longitudinal direction of the fiber yarn, so it exhibits dark and light colored parts due to the structure localized by dyeing. Although it is good for obtaining a slab-like appearance, it is difficult to obtain a natural appearance, and the stretchability tends to be inferior to that having no thick slab-like appearance.
Furthermore, Patent Document 7 and Patent Document 8 disclose stretchable conjugate fibers having a good swell feeling and a natural appearance, but according to these patent documents, they are good when dyed disperse dyes. Although dyeability can be obtained, it is difficult to obtain a practical strength during cationic dyeing.

Japanese Patent Laid-Open No. 5-295670 Japanese Patent Laid-Open No. 11-81069 JP-A-5-239714 JP-A-10-102318 JP 2000-160443 A JP 2001-115344 A JP 2004-124271 A JP 2004-183141 A

  The present invention relates to a cationic dye-dyeable composite polyester fiber that exhibits sufficient stretchability and swelling when made into a fabric.

In order to solve the above-mentioned problems, the present inventors have made use of a cationic dye-dyeable composite polyester multifilament fiber, in which the single filaments constituting each multifilament fiber have thick and thin spots in the fiber axis direction and variations in the single fiber diameter. As a result of extensive studies on the stretchability and the passage stability of the production process, the present invention has been achieved.
That is, the present invention is a fiber composed of a composite multifilament in which two kinds of polyester polymers having different melt viscosities are joined, and the single fiber constituting the multifilament fiber has thick spots in the fiber axis direction. Cationic dye characterized in that the ratio of the single fiber diameter of the thickest single fiber to the thinnest single fiber in any cross section in the fiber is 1.2 to 2.4, and the strength is 2.0 cN / dtex or more In dyeable polyester composite multifilament fibers.
The present invention also resides in the above-mentioned cationic dyeable dyeable polyester composite multifilament having a coefficient of variation of thickness spots as a multifilament fiber of 0.30 to 1.20 and a crimp rate (cc) of 20 to 45%. .

Furthermore, the present invention relates to a cationic dye-dyeable polyester polymer having a melt viscosity Via ≧ 8.3 × 10 ² poise and a viscosity Vib ≦ 8.0 × 10 ² poise (Via and Vib are temperatures of 280 ° C. of A and B polymers, respectively). , A melt viscosity at a shear rate of 2.43 × 10 ³ (second ⁻¹ )) is spun at a take-up speed of 2500 m / min or less. The present invention resides in a method for producing a cationic dye-dyeable polyester composite multifilament fiber, characterized in that heating roller stretching is performed under conditions satisfying the formulas (2) to (6).
Via-Vib> 3.0 × 10 ² poise (1)
MDR × 0.45 ≦ DR1 ≦ MDR × 0.65 (2)
1.000 ≦ DR2 ≦ 1.300 (3)
DR1> DR2 (4)
Tg ≦ TDR1 ≦ Tc (5)
Tg + 20 ° C. ≦ TDR2 ≦ Tc (6)
(In the formula, Via and Vib are the same as described above, MDR represents the maximum draw ratio of the undrawn yarn at a draw temperature of 85 ° C. DR1 is the first-stage draw ratio, DR2 is the second-stage draw ratio, and TDR1 is 1. Roller temperature in the stage drawing, TDR2 is the heat setting temperature in the second stage drawing, Tg is the glass transition temperature (° C.) of the undrawn yarn, and Tc is the crystallization temperature (° C.) of the undrawn yarn. When the crystallization temperature and the glass transition temperature of each undrawn yarn are measured at two points, the lower temperature is the crystallization temperature and the higher temperature is the glass transition temperature.)

  Furthermore, the present invention is a woven or knitted fabric characterized in that it comprises fibers composed of the above-mentioned cationic dyeable dyeable polyester composite multifilament and has a woven / knitted fabric shrinkage ratio (LC) of 20 to 40%.

  The cationic dye-dyeable polyester composite multifilament fiber of the present invention has not only a dark appearance and a light-colored portion but not a natural appearance when it is made into a fabric, and has a sufficient swelling and stretchability. Moreover, it can be set as the woven / knitted fabric which has practically sufficient strength in the garment application field.

Hereinafter, preferred embodiments of the present invention will be specifically described.
In the present invention, the cationic dyeable polyester polymer refers to a polyester that is mainly dyeable or dyeable to a cationic dye, with ethylene terephthalate as the main repeating unit.
The cationic dye-dyeable polyester is a modified polyester obtained by copolymerizing ethylene terephthalate with a metal salt such as sodium sulfoisophthalic acid or sodium sulfonaphthalenedicarboxylic acid, or an acid group-containing ester-forming compound such as a sulfonate group, preferably ethylene terephthalate. Examples thereof include a modified polyester obtained by copolymerizing 5-sodium sulfoisophthalic acid with 1.3 to 3.5 mol%.

  In addition, cationic dye-dyeable polyester is a metal salt such as sodium sulfoisophthalic acid, sodium sulfonaphthalenedicarboxylic acid, and other acid group-containing esters such as sulfonate group for ethylene terephthalate for the purpose of improving easy dyeability for cationic dyes. It may be a copolymer polyester obtained by copolymerizing other copolymer components other than the functional compound, and a polyester mixture containing a small amount of blend components such as polyalkylene glycol, alkyl sulfonic acid and inorganic substances. As other copolymerization components, aromatic dicarboxylic acids, aliphatic dicarboxylic acids, aliphatic diols, alicyclic diols, and aromatic diols can be used. Specifically, isophthalic acid, adipic acid, sebacin Examples include acid, 1,4-butanediol, cyclohexanediol, ethylene oxide adduct of bisphenol A, and the like.

  The cationic dye-dyeable polyester multifilament fiber of the present invention is required to be a composite multifilament fiber in which two kinds of polyester polymers having different melt viscosities are bonded in order to develop stretchability. In order to obtain good stretchability when a composite fiber is used, any combination of different melt viscosities may be used as long as it has a dye dye seat on at least one side. A combination of a low-viscosity product and a high-viscosity product with the same cationic dye dyeable polymer may be used. In this case, the polyester polymer (A) which is one component having a different melt viscosity has a high viscosity and acts as a high shrinkage component, and the polyester polymer (B) which is the other component has a low viscosity and acts as a low shrinkage component.

In the present invention, the two types of polyester polymers (A) and (B) having different melt viscosities may be joined in any manner as long as they exhibit good stretch properties when made into a composite fiber. A side-by-side type or an eccentric core-sheath type is preferable, and a side-by-side type is preferable in order to obtain a high stretchability.
Further, in the present invention, the single fiber constituting the multifilament fiber has thick and thin spots in the fiber axis direction, and the ratio of the single fiber diameter of the thickest single fiber to the thinnest single fiber in any cross section in the multifilament fiber is It is 1.2 to 2.4, and the strength needs to be 2.0 cN / dtex or more. When thick parts and details are mixed in the fiber axis direction of the single fiber constituting the multifilament fiber, a difference in fiber orientation occurs in the longitudinal direction of the single fiber, and known post-processing such as false twist, mixed fiber, and dyeing. Occasionally, when heat treatment is performed, a difference in shrinkage occurs in the single fiber, and when it is made into a fabric, a feeling of swelling is obtained. Furthermore, if the strength of the drawn yarn is less than 2.0 cN / dtex, the polyester fiber for clothing is not suitable for clothing because practical strength cannot be obtained.

Moreover, the cationic dye-dyeable composite polyester multifilament fiber of the present invention has a coefficient of variation (CV) of thickness spots as a multifilament fiber of 0.30 to 1.20, and a crimp ratio (CC) of 20 to 45. % Is preferred. Thereby, practical intensity | strength is acquired by disperse | distributing a thick part and detail moderately in the fiber-axis direction of a single fiber. When the thick portion and the details are localized, the portion where the single fiber strength is weak is concentrated as the fiber yarn due to the low orientation of the thick portion, and practical strength for clothing cannot be obtained.
The ratio of the single fiber diameter of the thickest single fiber to the thinnest single fiber in any cross section in the multifilament fiber needs to be 1.2 to 2.4. The lower limit of the thickness ratio is preferably 1.2 or more, more preferably 1.3 or more. The upper limit is preferably 2.4 or less, more preferably 1.8 or less. When a thick part and details are mixed in the single fiber axis direction, a difference in fiber orientation occurs in the single fiber longitudinal direction. It is known that due to the difference in fiber orientation, a shrinkage difference is produced in the single fiber when the heat treatment is performed during known post-processing such as false twisting, blending, and dyeing, and the fiber is swollen.
If the lower limit of the thickness ratio is less than 1.2, the single fiber fineness difference between the thick part and the detail is small in the fiber axis longitudinal direction of the single fiber. The difference is difficult to obtain, and the feeling of swelling when made into a fabric is insufficient. Also, if the upper limit exceeds 2.4, the fiber orientation difference between the thick part and the detail of the single fiber is large, so that the difference in elongation between the thick part and the detail becomes large. There is.

As for the variation coefficient (CV) of the thickness variation as the whole multifilament fiber, the lower limit is preferably 0.30 or more, more preferably 0.35 or more, and the upper limit is preferably 1.20 or less, more preferably 1.0 or less. It is. When the lower limit is less than 0.3, the thickness difference between the single fibers in the multifilament fiber becomes small, so that the crimp form difference between the single fibers becomes small, and the desired swell feeling is obtained. Can not be. On the other hand, when the upper limit exceeds 1.20, when heat treatment is performed during known post-processing such as false twisting, blending, and dyeing, as multifilament fibers, thick portions and details are localized in the fiber yarn axis direction, The shrinkage of the thick part of the multifilament fiber becomes notably rough fiber, and the difference in elongation between the thick part and the detail is large, and thus problems in process stability such as thread breakage occur during yarn production. Furthermore, a thick and fine slab-like appearance occurs when dyed. Furthermore, since the contracted portion concentrates due to the localization of the thick portion and the details, it is not possible to obtain a fiber exhibiting the natural appearance and bulge that is the object of the present invention after dyeing.
Further, in the present invention, the crimp ratio (CC) needs to be 20 to 45%. If the CC is less than 20%, sufficient stretchability cannot be obtained. If it exceeds 45%, the form of the woven or knitted fabric is not stable.

  The polyester composite multifilament fiber of the present invention preferably has a lower limit of elongation (DE) of 30% or more, more preferably 35% or more, and an upper limit of 70% or less, more preferably 60% or less. When the elongation exceeds 70%, sufficient crimping is difficult to occur when a woven or knitted fabric is obtained, and it is difficult to obtain satisfactory stretch performance. If it is less than 30%, the occurrence of thick spots tends to be insufficient in the fiber axis direction of the single fiber, and it tends to be difficult to obtain the desired bulge effect.

Next, the production method of the cationic dyeable polyester composite multifilament fiber of the present invention will be described in detail.
In the present invention, a cationic dye-dyeable polymer having a viscosity Via ≧ 8.3 × 10 ² poise (melt viscosity of polymer A) at a temperature of 280 ° C. and a shear rate of 2.43 × 10 ³ (second ⁻¹ ), A polyester polymer having a viscosity Vib ≦ 8.0 × 10 ² poise (melt viscosity of the polymer B) and a polyester polymer (A) satisfying the following formula (1) and a polyester polymer (B) of 2500 m / min or less It is necessary to stretch the undrawn yarn of the joining type composite fiber spun at the take-up speed under the condition of satisfying the following formulas (2) to (6) with a heating roller.
Via-Vib> 3.0 × 10 ² poise (1)
MDR × 0.45 ≦ DR1 ≦ MDR × 0.65 (2)
1.000 ≦ DR2 ≦ 1.300 (3)
DR1> DR2 (4)
Tg ≦ TDR1 ≦ Tc (5)
Tg + 20 ° C. ≦ TDR2 ≦ Tc (6)
(In the formula, Via and Vib are the same as above, MDR represents the maximum draw ratio of the undrawn yarn at a draw temperature of 85 ° C. DR1 is the first-stage draw ratio, DR2 is the second-stage draw ratio, and TDR1 is 1. Roller temperature in the stage drawing, TDR2 is the heat setting temperature in the second stage drawing, Tg is the glass transition temperature (° C.) of the undrawn yarn, and Tc is the crystallization temperature (° C.) of the undrawn yarn. When the crystallization temperature and the glass transition temperature of each undrawn yarn are measured at two points, the lower temperature is the crystallization temperature and the higher temperature is the glass transition temperature.)
The difference in melt viscosity between the polyester polymer (A) and the polyester polymer (B) at a temperature of 280 ° C. and a shear rate of 2.43 × 10 ⁻³ (second ⁻¹ ) needs to be larger than 3.0 × 10 ⁻¹ poise. It is. The polyester polymer (A) which is one component having a different viscosity has a high viscosity and acts as a high shrinkage component, and the polyester polymer (B) which is the other component has a low viscosity and acts as a low shrinkage component. When the difference in intrinsic viscosity is 0.145 or less, the shrinkage difference between the polyester polymer (A) and the polyester polymer (B) is small, the expression of crimp is insufficient, and the stretch performance cannot be obtained.

Moreover, it is preferable that the high viscosity component is copolymer polyethylene terephthalate which copolymerized 5-15 mol% of the 3rd component among two types of polyester polymers from which melt viscosity differs.
If the third component is less than 5 mol%, it is difficult to obtain sufficient crimping power, and if it exceeds 15 mol%, the melting point is remarkably lowered and not only composite spinning itself becomes difficult, but also crimping power tends to be insufficient.
Examples of the third component include aromatic dicarboxylic acids other than terephthalic acid components, acid components such as aliphatic dicarboxylic acids, aliphatic diols other than ethylene glycol components, alicyclic diols, diol components such as aromatic diols, Specifically, isophthalic acid, adipic acid, sebacic acid, 1,4-butanediol, cyclohexanediol, bisphenol A ethylene oxide adduct, sulfoisophthalic acid metal salt, 2,2-bis [4- (2-hydroxyethoxy) Phenyl] propane and the like, and isophthalic acid, adipic acid, sulfoisophthalic acid metal salt, and 2,2-bis [4- (2-hydroxyethoxy) phenyl] propane are particularly preferable. These third components may be used alone or in combination of two or more.

  In order to form a composite fiber from the polyester (A) and the polyester (B), the high viscosity side is preferably a cationic dyeable polyester. As the cationic dyeable component, a modified polyester obtained by copolymerizing ethylene terephthalate with an acid group-containing ester-forming compound such as a metal salt sulfonate group such as sodium sulfoisophthalic acid or sodium sulfonaphthalenedicarboxylic acid, more preferably 5 to ethylene terephthalate. -The modified polyester which copolymerized 1.3-3.5 mol% of sodium sulfoisophthalic acid is mentioned.

The joining of two types of polyester polymers having different melt viscosities according to the present invention may be any joining as long as a good stretch property is exhibited when a composite fiber is formed. A side-by-side type or an eccentric core-sheath type is preferably used, and a side-by-side type is more preferably used to obtain a high stretchability.
The joining ratio (mass ratio) W of the polyester polymer (A) / polyester polymer (B) at the time of composite spinning is preferably 4/6 <W <6/4 in order to give a crimp expression in the form of the composite fiber. . If the joining ratio is out of the above range, the yarn-forming property tends to be lowered, and the crimping ability in the form of the composite fiber tends to be insufficient.

In the present invention, the take-up speed at the time of spinning when the polyester polymer (A) and the polyester polymer (B) are composite-spun is such that the orientation degree of the undrawn yarn is kept relatively low, and the thickness in the fiber axis direction during drawing is reduced. In order to facilitate the formation of fine spots, it is necessary to set it to 2500 m / min or less. When the take-up speed exceeds 2500 m / min, the degree of orientation of the undrawn yarn becomes high and it becomes difficult to form thick spots. The unstretched yarn needs to be stretched in two stages with a heating roller under the conditions satisfying the formulas (2) to (6).
In the formula (2), if DR1 is less than MDR × 0.45, sufficient crimp expression cannot be obtained, and if it exceeds MDR × 0.65, formation of thick spots between single fibers of multifilament fibers It becomes difficult to obtain the swell feeling that is the object of the present invention.
Further, in the above formula (3), when DR2 is less than 1.000, thick spots between single fibers formed with DR1 are localized to have a slab-like appearance, and exceed 1.300. However, since the thick spots are localized in the same manner, the thick spots are not dispersed between the single fibers, and the desired bulge cannot be obtained. For this reason, it is necessary that DR1> DR2 as in the equation (4). When DR2 exceeds DR1, the thick and thin spots between the single fibers formed with DR1 are localized by stretching, so that a slab-like appearance is obtained, and the thick spots are dispersed between the single fibers to develop swelling. It becomes difficult.

As shown in the above formula (5), the secondary transition point TDR1 is Tg ≦ TDR1 ≦ Tc, and the neck point generation of the undrawn yarn is generated in the first stage under the condition of the above formula (2). By being on the roller, the neck point is dispersed, and thick and thin variations can be generated between the single fibers. When TDR1 is less than Tg or exceeds Tc, the dispersibility is poor due to the occurrence of a neck point in stretching, and the resulting thick and fine yarn has a slab-like appearance, so that the intended yarn of the present invention cannot be obtained.
Further, as shown in the above formula (6), when TDR2 is less than Tg + 20 ° C., the degree of orientation of the obtained fiber is low and the strength is insufficient, and when Tc is exceeded, the thick part and details of the single fiber are localized, and the multifilament The fiber becomes a slab-like fiber with thick parts and details localized.
Furthermore, in the present invention, the drawing needs to be performed with a heating roller. In the drawing with a heat pin, the drawing point is fixed on the heat pin, and the thick part and details of the single fiber are localized. It becomes a slab-like fiber with thick parts and details localized.

Further, the woven or knitted fabric made of the cationic dyeable polyester fiber of the present invention or a fiber containing the same needs to contain a polyester composite multifilament fiber and have a fabric shrinkage (LC) of 20 to 40%. If the LC is less than 20%, sufficient stretch properties cannot be obtained. If it exceeds 40%, the form of the knitted or knitted fabric is not stable.
These woven and knitted fabrics are obtained by, for example, subjecting the polyester composite multifilament fibers obtained in the present invention to a woven or knitted fabric by a known method after dyeing and / or blending the fibers and dyeing the fibers. Obtainable.

Hereinafter, the present invention will be specifically described by way of examples. In addition, evaluation of the characteristic value in an Example depended on the following method.
(Single fiber diameter ratio (thickness ratio))
The cross section was observed with an optical microscope at an arbitrary position in the longitudinal direction of the multifilament fiber, the single fiber diameter was measured, and the ratio of the single fiber diameter of the thickest part to the thinnest part was determined.
(Coefficient of variation of thickness variation as a whole thread (CV))
The variation coefficient CV (%) of the thickness of the yarn was measured under the conditions of a yarn speed of 15 m / min, a range of ± 12.5%, and a normal mode, using a measuring instrument industry Co., Ltd. yarn unevenness tester KET80C.

(Crimping rate CC)
Create a cocoon of sample yarn with a winding of 10 turns with a frame circumference of 1 m, wrap two places so that the cocoon does not get disturbed, repeat the process twice, making it into a figure of 8 and folding it into two. Then, wrap in gauze, put in a wire mesh box so that it will not float when immersed in a water bath, and immerse in a thermostat adjusted to 90 ° C. for 20 minutes. Remove the wire mesh box from the thermostatic chamber, drain the water, and place it on the filter paper so that the bottle does not get disturbed. Leave it for 20 hours or more and let it dry naturally and loosen any excess entanglement, taking care not to stretch the crimp. Apply an initial load of 49/25000 cN × 20 per display decitex (1.1 dtex) and measure the length (L0) after 1 minute. After weighing the initial load, apply a measurement load of 49/500 cN × 20 per display decitex, measure the length (L1) after 1 minute, leave it for 2 minutes after dewetting, and then reapply the initial load and 1 minute later Measure the length (L2). The crimp rate CC is calculated by the following formula.
Crimp rate CC (%) = (L1-L2) / L1 × 100

(Elongation (DE))
Using an autograph system SD-100-C manufactured by Shimadzu Corporation, measurement was performed under the conditions of a sample length of 20 cm and a tensile speed of 20 m / min.
(Textile shrinkage (LC))
Sample yarn is twisted under the conditions of twisting coefficient K = 100 (T = K × √D T is the number of twists per meter, D is the fineness of the sample yarn), temperature 70 ° C., humidity 90% RH The weft yarn set for 40 minutes below is used as the weft yarn, and the warp yarn density is 39.6 yarns / cm with the number of yarns driven (number / cm) = 311.1 / √D from the fineness (D) of the sample yarn. After weaving 56 dtex 18 filament yarn set as warp as warp, mark it at 1 m length in the weft direction of the fabric (L0), cut out a 10 cm width sample cloth parallel to the weft, 130 degrees C x 30 minutes , Hot water treatment. After air-drying the sample fabric treated with hot water, one end is fixed and hung vertically, a load of 0.45 g / dtex is applied to the other lower end, the distance (L1) between the marks on the tip is measured, and the fabric shrinks The ratio (LC) = (L0−L1) / L0 × 100.

(Melt viscosity (Vi))
After the polymer was vacuum-dried at 120 ° C. for 8 hours, using a capillograph (1-B type manufactured by Toyo Seiki Co., Ltd.), a capillary having a capillary length of 10 mm and a diameter of 1.0 mm, a temperature of 280 ° C. and a share rate of 2.432 × 10 ^The melt viscosity Vi (poise) was measured at ^-3 (second ^-1 ).
(Textile texture)
The tensile elasticity of the sample fabric after the wet heat treatment used for the measurement of the fabric shrinkage was evaluated by the following criteria by a sensory test based on tactile sensation.
○: Both elongation and impact resilience are very good.
Δ: Both elongation and impact resilience are good.
X: Both elongation and impact resilience are insufficient.
(Textile appearance)
The sample fabric after the wet heat treatment used for the measurement of the fabric shrinkage rate was dispersed dye Color. Index Basic Blue 117 1.0 o. w. The fabric was dyed at f% and a dyeing temperature of 130 ° C., and the appearance of the fabric was visually evaluated according to the following criteria.
○: There is no slab appearance and a plain appearance as a fabric.
X: Light and shade due to slab-like appearance, thick part, and details are generated.

Example 1
Copolymer polyethylene terephthalate having a melt viscosity Via = 1.10 × 10 ⁻³ poise obtained by copolymerizing 1.5 mol% of 5-sodium sulfoisophthalic acid (DMS) and 10 mol% of adipic acid with polyethylene terephthalate, polymer (A), Vib = 7.44 × 10 ⁻³ poise of polyethylene terephthalate is the polymer (B), the spinning temperature is 280 ° C., the two polymer streams are joined in plane symmetry upstream of the spinning discharge hole, and the joining ratio (weight ratio) ) 5/5, spun from a composite spinneret having 36 discharge holes having a pore diameter of 0.3 mm and a length of 1.5 mm. The spun yarn was cooled and oiled, and then wound at a take-up speed of 1800 m / min to obtain a 102 dtex / 36 filament composite fiber undrawn yarn.
The obtained undrawn yarn was drawn under the conditions shown in Table 1 to obtain a drawn yarn of 63 dtex / 36 filament polyester composite multifilament fiber. Table 1 shows the evaluation results of the cationic dyeable polyester composite multifilament fibers obtained.

(Example 2)
An undrawn yarn of 117 dtex / 48 filaments was obtained using a composite spinneret having 48 discharge holes under the same spinning conditions using the same polymer as that used in Example 1.
The obtained undrawn yarn was drawn under the conditions shown in Table 1 to obtain a 82 dtex / 48 filament polyester composite multifilament fiber. Table 1 shows the evaluation results of the cationic dyeable polyester composite multifilament fiber drawn yarns obtained.

(Comparative Example 1)
An undrawn yarn was obtained under the same spinning conditions as in Example 1, except that the undrawn yarn fineness was changed to 115 dtex / 36 filament in Example 1.
The obtained undrawn yarn was drawn under the conditions shown in Table 1 to obtain a 62 dtex / 36 filament polyester composite multifilament fiber. Table 1 shows the evaluation results of the cationic dyeable polyester composite multifilament fibers obtained. The obtained polyester composite multifilament fiber had a large CV, the woven fabric had a slab appearance, there was a difference in shrinkage between the thick part and the details of the slab, lacked a feeling of swelling, and the strength was inferior for clothing.

(Comparative Example 2)
A cationic dyeable polyester composite multifilament fiber was obtained in the same manner as in Example 2 except that the drawing conditions were changed to those shown in Table 1. Although there was no slab-like appearance, the ratio of the single fiber diameter of the thickest single fiber to the thinnest single fiber was small, resulting in a feeling of lack of swelling.

Claims (4)

  A fiber composed of a composite multifilament in which two types of polyester polymers having different melt viscosities are joined, and the single fiber constituting the multifilament fiber has thick spots in the fiber axis direction, and an arbitrary cross section in the multifilament fiber The ratio of the single fiber diameter of the thickest single fiber to the thinnest single fiber is 1.2 to 2.4, and the strength is 2.0 cN / dtex or more. Filament fiber.   The cationic dyeable dyeable polyester fiber according to claim 1, wherein the coefficient of variation (CV) of thickness spots as a multifilament fiber is 0.30 to 1.20, and the crimp ratio (CC) is 20 to 45%. A cationic dye-dyeable polyester polymer having a melt viscosity Via ≧ 8.3 × 10 ² poise and a viscosity Vib ≦ 8.0 × 10 ² poise (Via and Vib are A and B, respectively, temperature 280 ° C. and share rate 2. The unstretched yarn of the joint type composite fiber obtained by spinning the polyester polymer of 43 × 10 ³ (second ⁻¹ ) at a take-up speed of 2500 m / min or less is represented by the following formula (2) to A method for producing a cationic dye-dyeable polyester composite multifilament fiber, characterized in that heating roller drawing is performed under a condition satisfying (6).
Via-Vib> 3.0 × 10 ² poise (1)
MDR × 0.45 ≦ DR1 ≦ MDR × 0.65 (2)
1.000 ≦ DR2 ≦ 1.300 (3)
DR1> DR2 (4)
Tg ≦ TDR1 ≦ Tc (5)
Tg + 20 ° C. ≦ TDR2 ≦ Tc (6)
(In the formula, Via and Vib are the same as described above, MDR represents the maximum draw ratio of the undrawn yarn at a draw temperature of 85 ° C. DR1 is the first-stage draw ratio, DR2 is the second-stage draw ratio, and TDR1 is 1. Roller temperature in the stage drawing, TDR2 is the heat setting temperature in the second stage drawing, Tg is the glass transition temperature (° C.) of the undrawn yarn, and Tc is the crystallization temperature (° C.) of the undrawn yarn. When the crystallization temperature and the glass transition temperature of each undrawn yarn are measured at two points, the lower temperature is the crystallization temperature and the higher temperature is the glass transition temperature.) A woven or knitted fabric comprising the cationic dyeable polyester composite multifilament fiber according to claim 1 and having a woven / knitted fabric shrinkage (LC) of 20 to 40%.