JP2700022B2 - Polyester multifilament yarn - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to polyester multifilament yarns and knitted yarns for knitted and woven fabrics, and more particularly, to both soft touch and dry touch while satisfying both bulkiness and beaminess. In addition to the effect of the irregular reflection of light, the presence of a large number of fine grooves on the fiber surface due to the action of alkali hydrolysis can be used to improve the dark color appearance, and can also give a subtle touch to fabric structures, such as blouses and suit fabrics The present invention relates to a self-extensible polyester multifilament yarn having fine surface grooves suitable for use in women's clothing.

[0002]

2. Description of the Related Art Conventionally, as an attempt to satisfy both a dry feeling and a soft feeling to a fabric structure, a partially fused type false twisted yarn or a thick and thin yarn is mainly used for a polyester structure using polyester multifilament yarn. Many approaches have been proposed. However, although the partially fused type false twisted yarn has been considerably improved in terms of production cost, the fused portion is given a sharp taste by the effect of fiber fusion, so that the fused portion is reduced at the time of alkali weight reduction treatment. In addition to strongly receiving the alkali hydrolysis action selectively, the welded portion becomes brittle, causing cut fuzz, etc. In addition, the woven or knitted fabric using the partially fused type false twisted yarn becomes poor in drape property etc. There was a problem.

Thick and thin yarns having a cross-sectional area distribution in the fiber axis direction have an orientation distribution in the fiber axis direction, and have an appropriate dry feeling and a high shrinkage rate which are considered to be the effects of the undrawn residual portion. It is characterized by having a moderate swelling due to the effect. However, thick part by alkali weight reduction treatment,
That is, the portion having a low birefringence is selectively strongly affected by the alkali hydrolysis action, which not only causes the appearance quality of the woven or knitted fabric to be significantly impaired due to cutting of single yarn, generation of fluff, etc. As a result, the thick portion having relatively poor strength is cut by a single thread due to friction, causing fluffing or pilling, and there is still a problem in terms of quality assurance of the woven or knitted fabric.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art, and makes it possible to obtain a yarn with good physical properties and stable production. The present invention relates to a self-extensible polyester multifilament yarn having a large number of surface microgrooves in directions. More specifically, when processed into a fabric structure, it satisfies both soft touch and dry feel, combines moderate bulkiness and beam strength, and has many fine grooves on the fiber surface due to alkali hydrolysis action. By making it present, the effect of diffuse reflection of incident light can be further improved to give a deep color impression, a subtle touch can be given to the fabric structure, and a self-elongation having a fine surface groove suitable for women's clothing applications such as blouses and suit fabrics It is an object of the present invention to provide a functional polyester multifilament yarn.

[0005]

The polyester multifilament yarn of the present invention is obtained by subjecting a melt-spun polyester multifilament undrawn yarn to a relaxation heat treatment so that the crystallinity (度 ρ) is 20% or less and the residual elongation is 140%. As described above, when the boiling water shrinkage (SHW) is 3% or less and the dry heat shrinkage (SHD) at 160 ° C. of dry heat is less than 0%, the resin exhibits substantially self-extensibility, and the structural integrity parameter (ε0.2) Is a polyester-based multifilament of 45 to 70%, and after forming a woven or knitted fabric, a large number of grooves extending in the direction perpendicular to the fiber axis are formed by alkali weight reduction treatment with a weight loss rate of 10% or more.

The polyester-based multifilament undrawn yarn used for the polyester multifilament yarn of the present invention is a polyester multifilament containing an aromatic dicarboxylic acid as a main acid component and an aliphatic glycol as a main glycol component, particularly polyethylene terephthalate and poly (polyethylene). The main object is butylene terephthalate and the like, and a part of terephthalic acid is alicyclic dicarboxylic acid such as dicarboxylic acid such as isophthalic acid, 5-sodium sulfoisophthalic acid and naphthalenedicarboxylic acid and hexahydroterephthalic acid. Acid or aliphatic dicarboxylic acids such as adipic acid and sebacic acid, and polyesters in which part of ethylene glycol is substituted with another glycol component such as trimethylene glycol or tetramethylene glycol. At best, it is not particularly add limited. Moreover, titanium dioxide,
When fine powder inert inorganic substances such as barium sulfate and kaolinite are contained, fine irregularities can be generated on the fiber surface by alkali weight reduction processing, and due to the synergistic effect with the surface fine grooves, dark color effect and delicate dry touch (Smoothness) can be imparted to the woven or knitted fabric, which is suitable for use.

The polyester multifilament undrawn yarn used for obtaining the polyester multifilament yarn of the present invention can be produced by ordinary melt spinning, but has a spinning take-off speed of 2000 to 40.
00m / min., More preferably 3000-3800
m / min. Even when the multifilament undrawn yarn in the range of less than 2000 m / min. Is subjected to relaxation heat treatment, it is not possible to impart sufficient self-extensibility, and as a result, the relaxed heat treated yarn shrinks, and the purpose of the present invention is It is not possible to impart a soft touch to the woven or knitted fabric resulting from the self-elongation. The spinning take-off speed is 4000m / min.
If the number exceeds 3, the degree of crystal orientation of the yarn becomes too large, the degree of self-elongation due to the crystal growth of the molecule in the fiber axis direction is small, and it is impossible to impart a sufficient soft feeling to the woven or knitted fabric.

[0008] The fineness of single yarn of the polyester multifilament yarn of the present invention is not particularly limited, but is not limited to 0.1.
What is necessary is just to employ | adopt suitably in the range of 5-10 denier. Also,
Since the polyester multifilament yarn of the present invention has a large number of surface microgrooves, when used alone as a woven or knitted fabric, stress concentration occurs at the microgroove portions, resulting in poor tear strength of the woven or knitted fabric and practical use. Intolerable. For this reason, when processing into an actual woven or knitted fabric, it is necessary to compensate for the strength and elongation by drawing or blending with another polyester-based multifilament drawn yarn or using a mixed fiber yarn. The composite ratio of the drawn yarn and the yarn of the present invention is not particularly limited, but an appropriate range is 40:60 to 70:30. In addition, the range of the total fineness after drawing or blending and forming a composite yarn is appropriately selected according to the purpose and application in a range of approximately 30 to 300 deniers when considering the use of women's clothing such as dresses, jackets, skirts and the like. This is not a limitation. Further, the multifilament drawn yarn to be combined may be not only a drawn yarn but also a thick and thin yarn having a random shrinkage distribution in the fiber axis direction.

The single cross-sectional shape of the polyester multifilament yarn of the present invention is not particularly limited, and may be a flat cross-section yarn, a polygon cross-section yarn, or the like, in addition to a round cross-section yarn or a triangular cross-section yarn. You may. Any of a solid cross section and a hollow cross section may be used. However, since a large number of fine grooves are formed, the relaxed heat-treated yarn of the polyester-based multifilament undrawn yarn becomes brittle in a considerable amount of strength. There is also a risk of causing thread breakage and fluffing. Therefore, it is considered that it is more preferable to use a solid-section yarn than a hollow-section yarn.

The polyester multifilament yarn of the present invention has a crystallinity (Χρ) of 20% or less and a residual elongation of 140%.
%, Boiling water shrinkage (SHW) is 3% or less, dry heat 160
The dry heat shrinkage (SHD) at 0 ° C. is less than 0%, has substantially self-extensibility, and has a structural integrity parameter (ε0.2
) Is 45 to 70%, and a groove extending in a direction perpendicular to the fiber axis is formed by alkali weight reduction treatment at a weight loss rate of 10% or more after weaving.

Here, the above physical properties are measured by the following measuring methods. (A) Crystallinity (Χρ) The density of the sample was measured in a thermostat at 20 ± 0.5 ° C. by a density gradient tube method, and the crystallinity (Χρ) was calculated by the following equation. For the density measurement by the density gradient tube method, n-pentane (specific gravity: 0.683) known as a light specific gravity liquid and carbon tetrachloride (specific gravity: 1.599) as a specific gravity liquid are prepared, mixed, and mixed. The liquid was given a density gradient. In addition, the average value of the number of times of the test 5 times was set as the measured value. Χρ = [dk (d-da)] / [d (dk-da)] × 100 (%) Χρ = crystallinity (%) dk = 1.47 g / cm ³ (density of PET perfect crystal) da = 1 .331g / cm ³ (PET density of fully amorphous) d = density of sample (g / cm ³⁾

(B) Shrinkage of boiling water (SHW) A sample was measured at 0.1 g / d using a measuring machine with a frame circumference of 1.125 m.
The initial load is applied, and the skein is wound back at a rate of 120 times / min to produce a small skein with 20 turns. The skein length L1 (mm) is measured by applying a weight 40 times the initial load. Subsequently, the weight is removed, and the body is immersed in boiling water (100 ° C.) for 30 minutes in such a manner that shrinkage is not hindered, taken out, wiped off with a blotter or a cotton cloth, and air-dried in a horizontal state. After air-drying, the weight is applied again and the skein length L2 (mm) is measured. The above L1 and L2 are substituted into the following equation, and the boiling water shrinkage (SHW) is measured. In addition, the average value of 5 times of the test is defined as the measured value. SHW = (L1−L2) / L1 × 100 (%)

(C) Dry heat shrinkage (SHD) A load of 1/30 g / d was applied to the sample, and its length L3 (mm)
Is measured. Next, the load is removed, and the sample is placed in a dryer and dried at 160 ° C. for 30 minutes. After drying, it is cooled, and a load of 1/30 g / d is applied again to apply its length L4 (m
m) is measured. The dry heat shrinkage (SHD) is calculated by substituting the above L3 and L4 into the following equation. In addition, the average value of 5 times of the test is defined as the measured value. SHW = (L3−L4) / L3 × 100 (%)

(D) Structural integrity parameter (ε0.2) Using a ε-meter manufactured by Bonn Electric Co., a sample length of 200 mm was measured while applying a load of 0.2 g / d, and the load was applied. While keeping the temperature, the treatment is performed in boiling water at a measurement temperature of 95 ° C. for 30 seconds, and the length L6 (mm) is measured. The structural parameter (ε0.2) is represented by the following formula, and the measured value is determined by averaging the five measurements. ε0.2 = (L6−L5) / L5 × 100 (%) where L5 is the sample length (200 mm) before the treatment.

(E) Residual elongation (DE) Using a Tensilon UTM-3-100 manufactured by Orientec, a tensile test was conducted at a sample length of 200 mm and a tensile speed of 200 mm / min, and the elongation until cutting the sample was performed. Was determined, and the measured value was taken as the average value of the five tests.

(F) Observation of fine grooves on fiber surface Using a S-501 type scanning electron microscope manufactured by Hitachi, Ltd., magnification 8
After observing the surface of the woven or knitted fabric after alkali reduction processing, the angle formed by the ridge of the groove, the maximum depth from the fiber surface to the deepest part, the width of the groove on the fiber surface, and the yarn The number of grooves formed per unit length was determined. The measured value was determined based on the average value of the measured values at 20 places.

The polyester multifilament yarn of the present invention must have a crystallinity (度 ρ) of 20% or less, more preferably 15% or less. The yarn is obtained by relaxing and heat-treating a polyester multifilament undrawn yarn melt-spun at a spinning take-off speed of 2,000 to 4,000 m / min. The multifilament undrawn yarn has a so-called high orientation state. The feature is that the degree of crystallization is relatively low, but after processing the undrawn yarn into a woven or knitted fabric by relaxing heat treatment and removing the shrinkage component without increasing the crystallinity as much as possible. It is presumed that the rate of crystal growth in the crystal c-axis direction, that is, in the fiber axis direction, due to wet heat treatment in the dyeing process is larger than the rate of thermal shrinkage of the yarn, and that the fiber substantially exhibits self-elongation. Is done.

The polyester multifilament yarn of the present invention must have a residual elongation of 140% or more. When the residual elongation is less than 140%, the residual elongation of the polyester multifilament undrawn yarn obtained by melt spinning is not so large, and as a result, the yarn is not heat-treated at a relaxation rate sufficient to give self-extensibility to the yarn. In addition, a soft touch cannot be sufficiently imparted to the woven or knitted fabric. The relaxation rate of the undrawn yarn in the relaxation heat treatment depends on the texture of the woven or knitted fabric and the operability at the time of the relaxation heat treatment, although it depends on the spinning take-off speed of the undrawn yarn. It must be adopted as appropriate. Further, there is no particular limitation on the heating body used for the relaxation heat treatment and the processing speed, but a non-contact heating body such as a slit heater or a tube heater is used as the heating body, and the processing speed is determined as a residence time in the heating body. It is preferable to set it for 0.05 to 0.2 seconds.

The polyester multifilament yarn of the present invention has a boiling water shrinkage (SHW) of 3% or less, more preferably 2% or less. If the boiling water shrinkage (SHW) exceeds 3%, the yarn is excessively shrunk in the wet-heat twist fixing and sizing steps following the twisting, and the wet-heat process such as scouring and relaxing after processing into a woven or knitted fabric. The self-elongation that appears is actually canceled out, and the woven or knitted fabric cannot be given a sufficiently soft feeling. The lower limit of the boiling water shrinkage of the relaxed heat-treated yarn is not particularly limited, but may be kept at -2% or more, preferably -1% or more in consideration of the process stability and the texture of the woven or knitted fabric. desirable. The boiling water shrinkage is -2%
If it is less than that, it means that self-extensibility is manifested even in boiling water at 100 ° C., and the yarn length difference due to self-extension is exhibited even in wet heat twist fixing and sizing process using a vacuum heat setter. There is a possibility that it will be a thread with lots of loops and slacks, and it is expected that the weaving and knitting process will not be able to pass through the following processes, and that self-extensibility after processing into a woven or knitted fabric will be exhibited. Both the soft feeling and the swelling feeling due to the effect are not satisfactory, which is not preferable.

Further, the multifilament yarn is required to have a structural integrity parameter (ε0.2) of 45 to 70%. The structural integrity parameter comprehensively determines the crystallinity and orientation of the fiber. The undrawn polyester multifilament yarn obtained at a spinning take-off speed of 2000 to 4000 m / min. By ordinary melt spinning has a structural integrity parameter (ε0.2) of about 20 to 40%.
However, when the unstretched yarn is subjected to the above-mentioned relaxation heat treatment to be in the range of 45 to 70%, self-extensibility can be imparted to the relaxed heat-treated yarn. Although this cannot be clearly explained, it is inferred that if the structural integrity parameter after relaxation heat treatment exceeds 70%,
Although the relaxed heat-treated yarn becomes a so-called low-orientation yarn, lowering the degree of orientation to that region means that the relaxation rate is excessively increased. The yarn may break due to loosening, which is not preferable. On the other hand, if the structural integrity parameter is less than 45%, the yarn has a high degree of crystallinity, it is difficult to change the structure of the yarn by relaxation heat treatment, and the degree of self-elongation by heat cannot be increased. .

The relaxed heat-treated yarn of the polyester multifilament yarn of the present invention is subjected to alkali weight reduction processing at a weight reduction rate of 10% or more to form grooves extending in the direction perpendicular to the fiber axis direction on the fiber surface. Although it depends on the characteristics of other polyester multifilament drawn yarns to be combined as a mixed fiber, etc., assuming that the polyethylene terephthalate normal drawn yarn is used as the drawn yarn, a relaxed heat-treated yarn of a polyester-based multifilament undrawn yarn is generally used. In order to selectively receive the alkali hydrolysis action more strongly, it is necessary to control so as not to be excessively embrittled. For general clothing use, the weight loss rate of the mixed fiber may be selected appropriately in consideration of the texture, the physical properties of the woven or knitted fabric, and the like in a range of approximately 10 to 30%.

When the polyester multifilament undrawn yarn is subjected to relaxation heat treatment, a non-contact heating method is employed as described above, and the residence time of the heating body is 0.05 to 0.2 seconds, more preferably 0.09 to 230 seconds. In order to impart self-extensibility to the relaxed heat-treated yarn of the polyester multifilament undrawn yarn, it is desirable to perform the relaxation heat treatment at an arbitrary set temperature in the range of 180 ° C, more preferably in the range of 180 to 220 ° C.

Since the polyester multifilament yarn of the present invention develops a large number of fine grooves on the fiber surface by the alkali weight reduction treatment, the polyester multifilament yarn has poor tear strength as compared with a fabric woven and knitted using a general polyester multifilament ordinary drawn yarn, Even if a woven or knitted fabric is used alone, it cannot be put to practical use. Therefore, it is necessary to supplement the strength and elongation by using a composite with another polyester multifilament yarn, generally a drawn polyester multifilament yarn, that is, a so-called aligned or mixed yarn. When a mixed fiber is used, a known interlace nozzle or the like or a Taslan nozzle or the like which forms a loop or a slack by a turbulent air flow can be used. When a Taslan nozzle or the like is used, there is a possibility that unwinding of the package may be caused by a loop or looseness, so that an appropriate amount of a synthetic fiber yarn-coning oil may be applied and wound around the package. When using an interlaced nozzle to mix fibers, the number of entangled fibers per meter of mixed yarn is 20 to
The presence of about 100 / m is preferable because problems such as yarn breakage in the subsequent steps can be reduced.

[0024] The drawn or blended yarn thus obtained is twisted, then subjected to low-temperature twist setting or low-temperature sizing, and then woven and knitted to obtain a fabric structure. By heat treatment (110 ° C to 200 ° C) such as processing, the relaxed heat-treated yarn of the polyester multifilament undrawn yarn exhibits self-extension, forms a loop portion of the entangled mixed fiber, and is further subjected to alkali weight reduction processing at a weight reduction rate of 10% or more. By forming fine grooves on the surface of the relaxed heat-treated yarn, it is possible to obtain a woven or knitted fabric having a good feeling of swelling, softness, and subtle dry touch.

[0025]

The present invention will be described below in detail with reference to examples. Of course, the present invention is not limited to the following embodiments. Note that L * in the examples is based on the following measurement method. (1) L * (whiteness) A color difference meter (MODEL TC manufactured by Tokyo Denshoku Co., Ltd.) is measured by a four-spectrometry method according to JIS Z-8722 (method for measuring object color).
-1500 MC-88) to measure L * of the dyed cloth (fabric). In addition, it was set as the measured value using the average value of the number of measurements 5 times. (Example 1) Spinning take-off speed of 3200 m / min. Polyester semi-dal round cross-section multifilament high-density undrawn yarn 40 denier 24 filament spun with 65% boiling water shrinkage at 45% by a non-contact slit heater with an ambient temperature of 200 ° C., relaxation rate 45%, processing speed 200 m / min . The relaxation treatment was performed under the conditions of a heater residence time of 0.18 seconds. The highly oriented undrawn yarn after the relaxation heat treatment has a crystallinity (Xρ) of 14.76.
%, Residual elongation 213%, structural integrity parameter (ε0.2
) Is 61.1% and the boiling water shrinkage (SHW) is -0.9.
%, Dry heat shrinkage (SHD) at 160 ° C.
It was confirmed that 6.3% showed substantially self-elongation.

The undrawn polyester multifilament yarn after the relaxation heat treatment has a boiling water shrinkage (SHW) of 16% and a dry heat shrinkage (SHD) at 160 ° C. of 18.5%.
Polyester multi-filament multifilament yarn was obtained by subjecting 10 filaments of a polyester semi-dal round cross-section multifilament ordinarily drawn yarn of 50 denier to air entangling with a high-pressure airflow at room temperature using a known interlace nozzle. The number of entangled composite yarns per meter of the yarn is 72.
This was a yarn having excellent handleability and having no cracks.

Using a double twister (No. 310-C) manufactured by Murata Machinery Co., Ltd., the polyester multifilament composite yarn was twisted at 300 T / m in the S twist direction as a warp, and a polyester multifilament semi-dull as a weft. Using a twisted yarn obtained by twisting a 150-denier 96-filament circular cross-section yarn in the S-twist and Z-twist directions at 1800 T / m in a twist direction and performing a twist-set at a temperature of 85 ° C. for 40 minutes using a vacuum heat setter, Has a production density of 1
It was woven into a plain weave of 62 pieces / inch and weft 70 pieces / inch. After scouring and relaxing, the mixture was finished to a weight reduction rate of 29% using a jet dyeing machine. Subsequently, it was dyed in dark black (formal black) using a liquid jet dyeing machine and subjected to a usual final setting to obtain a dyed cloth having a finishing density of 186 lines / inch and 83 lines / inch.

The surface of the dyed cloth was observed at a magnification of 800 times using a scanning electron microscope. As a result, the relaxed heat-treated yarn of the polyester multifilament undrawn yarn formed many transverse grooves extending in the direction perpendicular to the fiber axis. It was confirmed that. The maximum depth of the lateral groove is visually about 5μ on average.
m, the width of the lateral groove on the fiber surface is visually averaged about 4 μm,
The number of the horizontal grooves formed was an average of 25 per 50 μm of the yarn length, and the angle formed by the V-shape of the horizontal grooves was about 30 ° on average visually. L * of the dyed cloth was 13.6, and it was a deep color tone that could be sufficiently used for black formal clothing for women. In addition, for the texture, it has a gentle feeling without a flurry, moderate swelling, subtle dry touch, soft touch, and even a moderate beam, waist, women's dress,
A completely new textured fabric suitable for blouse, jacket and skirt applications.

Comparative Example 1 The spinning take-off speed was 3200 m / min. Polyester semi-dal round cross-section multifilament high-density undrawn yarn of 40 denier and 24 filaments having a boiling water shrinkage of 65% spun at a temperature of 170 ° C. using a contact type heater having a surface temperature of 170 ° C., a relaxation rate of 0%, and a processing speed of 200 m / min. And a constant-length heat treatment under the condition of a heater residence time of 0.09 seconds. The highly oriented undrawn yarn after the constant-length heat treatment has a crystallinity (Xρ) of 42.25.
%, Residual elongation 113%, structural integrity parameter (ε0.2
) Is -0.44%, and boiling water shrinkage (SHW) is 1.7.
%, Dry heat shrinkage (SHD) at 160 ° C.
3%. A dyed cloth was obtained in the same manner as in Example 1 except that the highly oriented undrawn yarn after the constant-length heat treatment was used.
The L * of the dyed cloth was 17.5, and the color tone was inferior to the dyed cloth of Example 1. In addition, the texture was good, and although the waist had a moderate feeling, the feeling of swelling and softness was insufficient. The surface was observed in the same manner as in Example 1 using a scanning electron microscope. However, no fine grooves were formed, no delicate smooth feeling could be felt, and the fabric was far from a new texture.

(Comparative Example 2) Polyester bright triangular cross-section multifilament multifilament highly oriented undrawn yarn 35 denier 18 filament spun at a spinning take-off speed of 3000 m / min and having a boiling water shrinkage of 72% using a drawing machine using a drawing machine. Under the conditions of 1.671 times and a drawing temperature of 80 ° C, a drawn polyester multifilament yarn of 20 denier and 18 filaments was obtained. The yarn was subjected to a relaxation heat treatment using a non-contact slit heater at an ambient temperature of 200 ° C. under the conditions of a relaxation rate of 45%, a processing speed of 540 m / min, and a heater residence time of 0.07 seconds. The yarn after the relaxation heat treatment has a crystallinity of 19.34%, a residual elongation of 80%, a structural integrity parameter (ε0.2) of 26.14%, a boiling water shrinkage (SHW) of -0.8%, and a dryness. A dry heat shrinkage (SHD) at a temperature of 160 ° C. was substantially self-elongated at −5.4%. A dyed cloth was obtained in the same manner as in Example 1 except that the above yarn was used. L * of the dyed cloth was 17.8, and the color tone of the dyed cloth was inferior to that of Example 1. Regarding the texture, due to the effect of self-stretching, it had moderate bulky and soft feeling, but lacked dry touch. The surface was observed using a scanning electron microscope, and no fine grooves were formed, and no subtle smoothness was felt.

[0031]

By using the self-extensible polyester multifilament yarn having the fine surface grooves of the present invention and forming it into a woven or knitted fabric, it has a soft feel, a dry feel, a moderate bulkiness, a beam and a waist, and It becomes possible to give a subtle smooth feeling due to the effect of the surface fine grooves and further a deeper color tone. By using this yarn, it is possible to provide a women's clothing material having a completely new texture.

[Brief description of the drawings]

FIG. 1 is an enlarged perspective view of a self-extensible polyester multifilament yarn having surface fine grooves according to the present invention after an alkali weight reduction treatment.

[Explanation of symbols]

 1: groove, 2: self-extensible polyester filament

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location D06M 11/38 D06M 5/02 G

Claims (2)

(57) [Claims] 1. A dry heat shrinkage (S) at a crystallinity (度 ρ) of 20% or less, a residual elongation of 140% or more, and a dry heat of 160 ° C.
HD) is less than 0% and the structural integrity parameter (ε0.
2) is a polyester-based multifilament having 45 to 70%, and contains at least a part of a filament yarn forming a large number of grooves extending in a direction perpendicular to the fiber axis by an alkali weight reduction treatment with a weight reduction rate of 10% or more. A polyester multifilament yarn characterized by the following. 2. The boiling water shrinkage (SHW) of the filament yarn.
The polyester multifilament yarn according to claim 1, wherein is less than 3%.