WO2023080184A1 - Polyester fiber and woven fabric - Google Patents

Abstract

The present invention relates to a polyester fiber which is formed of two kinds of polyester polymers, while having an elongation ratio A of 60% to 90% under a load of 3.5% with respect to fineness.

Description

polyester fibers and textiles

The present invention relates to polyester fibers and textiles. More specifically, the present invention relates to a woven fabric having excellent soft stretchability, which is composed of conjugate fibers made of two types of polyester polymers.

In recent years, among woven and knitted fabrics, stretch woven and knitted fabrics with stretchability have been strongly desired because of their comfort. In order to satisfy this demand, for example, a large number of woven and knitted fabrics are used in which stretchability is imparted by mixing polyurethane fibers with polyester fibers. However, polyurethane fibers are difficult to be dyed with disperse dyes used for polyester fibers, so that the dyeing process is complicated, and they become brittle with long-term use, resulting in a decrease in stretchability. In order to avoid such drawbacks, the application of crimped yarn of polyester fibers instead of polyurethane fibers has been investigated.

A polyester fiber whose main component is polytrimethylene terephthalate (hereinafter referred to as PTT) has a high elongation recovery rate and a low Young's modulus, so it has excellent soft stretchability. By using this PTT in side-by-side type or eccentric core-sheath type composite fibers, it is possible to make a soft stretchable fabric, and composite fibers using PTT are actively researched and developed in a wide range of applications from clothing to non-clothing. is done.

For example, the invention described in Patent Document 1 and the invention described in Patent Document 2 are composed of two types of polyester-based polymers, and at least one of them is made of a polyester fiber mainly composed of PTT, thereby expressing a coiled crimp. As a result, it exhibits high bulkiness and excellent crimp development force, and proposes a high-quality fabric with excellent soft stretchability.

Further, the invention described in Patent Document 3 proposes a stretch fiber which is an eccentric core-sheath type composite fiber composed of two types of polymers, and which has improved wear resistance by covering the surface layer with a thin skin for the sheath portion. .

Japanese Patent Application Laid-Open No. 2001-55634 Japanese Patent Application Laid-Open No. 2002-061031 WO2018/110523

However, the conjugate fibers described in Patent Documents 1 and 2, particularly the eccentric sheath-core type conjugate fiber described in Patent Document 3, are woven as wefts of fabrics because the distance between the centers of gravity between the two components is narrow (hereinafter referred to as weft beating). ), the yarn is elongated and the coil pitch C of the yarn in the fabric before the heat treatment becomes large ((1) in FIG. 1). As a result, the stretch allowance of the woven fabric is reduced, and there is a problem that the original stretch performance of the yarn cannot be exhibited. For example, as shown in FIG. 1(1), in a fabric constructed by using conventional composite fibers for weft A and warp B, the weft A is stretched during weft beating, resulting in an increased coil pitch.

In addition, composite fibers with a small single yarn fineness for thin fabrics are easily affected by tension during weft beating, and the above-mentioned problem is remarkable.

The present invention is intended to solve the above-mentioned problems, and since the coil pitch can be maintained without stretching the fibers during weft beating, the woven fabric with the designed width has excellent soft stretchability and high fabric without wrinkles and wrinkles. It is a polyester fiber that can provide high-quality fabrics. For example, as shown in (2) of FIG. 1, in a fabric composed of the polyester fiber of the present invention using weft A and warp B, the weft A is not elongated during weft beating and the coil pitch C is maintained. can.

The above problems are solved by the following means.
(1) A polyester fiber composed of two types of polyester polymers and having an elongation rate A of 60% to 90% at a load of 3.5% relative to the fineness.
(2) The difference in the elongation rate between the elongation rate A at a load of 3.5% with respect to the fineness and the elongation rate B at a load of 18.0% with respect to the fineness is 5.0% to 25.0. %, the polyester fiber according to (1).
(3) The polyester fiber according to (1) or (2), which has a single filament fineness of 1.5 dtex or less.
(4) The polyester fiber according to any one of (1) to (3), wherein the difference in degree of orientation between the two polyester polymers in the cross section of the fiber is 2.5 to 4.5.
(5) A woven fabric composed of the polyester fiber according to any one of (1) to (4) above, and having an elongation rate in the weft direction of the fabric of 5% to 30%.

The polyester fiber of the present invention has excellent soft stretchability and can provide high-quality stretch fabrics free from crimps and wrinkles.

(1) and (2) of FIG. 1 are cross-sectional schematic diagrams of fabrics when the fibers are woven, and (1) of FIG. FIG. 1(2) is a diagram for explaining a woven fabric made of polyester fibers according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing an example of melt spinning equipment used in the spinning process (direct spinning drawing method) preferably used in the present invention.

The polyester fiber of the present invention is a polyester fiber composed of two types of polyester polymers, and has an elongation rate A of 60% to 90% at a load of 3.5% with respect to fineness.

The polyester fibers of the present invention are composed of two types of polyester polymers.
Examples of the polyester polymer include polyethylene terephthalate or its copolymer, polybutylene terephthalate, PTT, polyethylene naphthalate, polylactic acid and the like.

The coiled crimp characteristics are expressed by arranging two components with different heat shrinkage as composite fibers. Since the ability is exhibited by the stretching behavior of the high-shrinkage component with the low-shrinkage component as a fulcrum, the polyester polymer used for the high-shrinkage component is required to have high elongation and recovery properties. PTT and polybutylene terephthalate are preferred as the high-shrinkage component in terms of mechanical properties and chemical properties. More preferably, the high-shrinkage component is PTT because it can increase the difference in shrinkage rate, and the low-shrinkage component is preferably polyethylene terephthalate.

The polyester fiber of the present invention has a composite cross section formed by joining two types of polyester polymers. The cross-sectional shape includes a side-by-side type, a core-sheath type, an eccentric core-sheath type, and a sea-island type. The eccentric core-sheath type means that the core component is covered with the sheath component, and the position of the center of gravity of the core component in the cross section of the fiber is different from the center position of the cross section of the composite fiber. An eccentric core-sheath type is preferred from the viewpoint of spinning stability and abrasion resistance when made into a fabric.

The polyester fibers of the present invention are long fibers and include processed yarns such as crimped yarns. The total fineness is 33dtex to 167dtex, and the number of filaments is 24f to 72f. The total fineness is preferably 56dtex to 84dtex and the number of filaments is preferably 48f to 72f from the viewpoint of soft stretchability when made into a woven fabric. More preferably, the total fineness is 56dtex and the number of filaments is 48f.

When weaving wefts, tension is applied to the yarn and the coil pitch is elongated. If the weft yarn is woven into the woven fabric while being stretched, the stretch allowance of the yarn after the woven fabric will be reduced. Since the stretch performance of the woven fabric deteriorates even after passing through the heat treatment process, it is an important factor for the stretch performance of the woven fabric that the yarn does not stretch even under the tension during weft beating. In other words, by stipulating the elongation rate in the low-load region assuming the tension during weft beating, the original stretch performance of the yarn can be fully exhibited even in the woven fabric.

Here, the elongation rate A at a load of 3.5% relative to the fineness indicates the degree of elongation of the yarn coil assuming a low tension during weft beating.

The elongation rate A (hereinafter referred to as elongation rate A) at a load of 3.5% with respect to the fineness is obtained by preparing two skeins of 10 m of the fiber sample and applying a load of 3.5% to the fineness ( Unit: g) and measure the sample length (L0) after 30 seconds, then apply a constant load of 100 g and measure the sample length (L1) after 30 seconds, and calculate the average value of the two pieces using the following formula. be.
Elongation rate A (%) = L0/L1 x 100
The polyester fiber of the present invention has an elongation rate A of 60% to 90%. By setting the elongation rate A to 90% or less, the weft coil in the woven fabric is not elongated, and the woven fabric has sufficient stretchability due to the elongation of the yarn.
On the other hand, the lower the elongation rate A, the better the stretchability of the fabric, but the smaller the coil pitch of the weft yarn, the higher the weave density due to shrinkage in the heat treatment process of the fabric, and the easier it is for wrinkles and creases. The elongation rate A is 60% or more in terms of quality. Preferably, it is between 75% and 85%.

The elongation rate B at a load of 18% with respect to the fineness (hereinafter referred to as elongation rate B) indicates the degree of elongation of the weft coil when the weft is constrained by the warp as a woven fabric.

This elongation rate B is obtained by preparing two skeins of 10 m of the fiber sample, applying a load (unit: g) of 18% to the fineness, measuring the sample length (L2) after 30 seconds, and then applying a constant load of 100 g. , and the sample length (L1) after 30 seconds is measured, and the average value of the two pieces calculated by the following formula.
Elongation rate B (%) = L2/L1 x 100
In the polyester fiber of the present invention, the difference between the elongation rate B and the elongation rate A (hereinafter referred to as elongation rate difference) is preferably 5.0% to 25.0%. That is, the difference in the elongation rate between the elongation rate A at a load of 3.5% to the fineness and the elongation rate B at a load of 18.0% to the fineness is 5.0% to 25.0%. Preferably. The larger the difference, the easier the weft stretches and the smaller the elastic force of the coil. By setting the elongation rate difference to 5.0% or more, the coil does not elongate under tension during weft beating or when it is constrained by the warp yarn, and the difference in the actual weaving width from the weaving width standard is small. is obtained, the inherent elastic force of the conjugate fiber can be fully exhibited in the woven fabric, and better stretchability can be obtained. By setting the elongation rate difference to 25.0% or less, a higher-quality woven fabric free from crimps and wrinkles can be obtained. More preferably 10.0% to 20.0%.

The polyester fiber of the present invention preferably has an orientation difference of 2.5 to 4.5 between the two types of polyester polymer components in the cross section of the fiber. The degree of orientation indicates the orientation of the molecular chains of the polyester component, and greatly affects the crystallinity and shrinkage force of the component. By setting the orientation difference between the two components to 2.5 or more, the difference in shrinkage performance between the two components is increased, the coil pitch is narrowed, and the elastic force is improved, resulting in better stretch when made into a woven fabric. You get sex. By setting the orientation difference to 4.5 or less, the elongation rate A is prevented from being excessively lowered, and grains and wrinkles can be further suppressed, which is preferable. It is more preferably 3.0 to 4.0.
The composite ratio of the polyester fiber of the present invention is preferably 80:20 to 20:80 from the viewpoint of spinning property, crimp performance development, and dimensional homogeneity of the coil pitch in the fiber length direction, and a more preferable composite ratio is 70:30 to 30:70. Composite ratio is the area ratio of two types of polyester polymer components constituting a single fiber in a cross-sectional photograph of the single fiber.

The polyester fiber of the present invention preferably has a single filament fineness of 1.5 dtex or less from the viewpoint of soft texture. A more preferable single yarn fineness is 1.2 dtex or less. A more preferable single yarn fineness is 0.8 dtex or less. On the other hand, generally, the thinner the single yarn fineness, the lower the elastic force of the coil. Therefore, the stretchability is affected by the tension during weft striking in weaving and the tension by warp restraint, and the stretchability decreases. As described above, when the elongation rate A is 90% or less and the elongation rate difference is 5.0% or more, even if the single yarn fineness is 1.5 dtex or less, the tension during weft beating in weaving and the tension restrained by the warp are affected. It is preferable because it is difficult to receive and can achieve both stretchability and softness.

It is preferable that the polyester fiber of the present invention has a stretch ratio in the range of 55 to 95%. The stretch ratio is a value indicating the degree of crimping, and the higher the stretchability, the higher the stretchability. A more preferable stretching/elongation rate is in the range of 65 to 85%.

Next, a preferred method for producing the polyester fiber of the present invention will be explained.
Examples of the method for producing the polyester fiber of the present invention include a method in which the fiber thread discharged from the spinneret is once wound on a drum and then drawn, and a method in which the fiber thread is continuously drawn in the spinning stage. . These manufacturing methods will be specifically described.

The polyester fiber of the present invention is produced by melt extruding two different types of polyester polymers, using a composite spinning machine, sending them to a predetermined composite pack, filtering both polymers in the pack, and then using a spinneret, for example, side-by-side type or It can be produced by a two-step method in which eccentric core-sheath type conjugate spinning is performed, the undrawn yarn is once wound, and then drawn to a predetermined breaking elongation with a conventional drawing machine. Alternatively, it can also be produced by a one-step method in which the fiber is extruded from a spinneret, subjected to conjugate spinning, and then drawn without being wound once. Considering that the fiber structure formation, that is, tension control from spinning to winding is easy, a one-step direct spinning and drawing method (hereinafter referred to as DSD method) is preferable.

In the present invention, in order to obtain fibers with excellent stretchability, the difference in intrinsic viscosity between the two types of polyester polymers is preferably 0.15 or more.

As a method for forming an eccentric core-sheath type composite cross section, a distribution plate type spinneret exemplified in Japanese Patent Laid-Open Nos. 2011-174215, 2011-208313, and 2012-136804. can be preferably used to obtain a desired cross-sectional shape.

In the production of the polyester fiber of the present invention, it is important to control the formation of the fiber structure from drawing to winding in order to control the elongation rate A within the desired range. The fiber structure formation control from drawing to winding can be controlled by drawing tension and relaxation tension, and the drawing tension and relaxation tension can be controlled within a desired range by the draw ratio and the speed of each roller. The spinning speed is preferably 900 m/min to 1400 m/min, and the draw ratio is preferably 3.0 to 4.0 times.

The drawing tension is preferably 0.5 cN/dtex to 1.1 cN/dtex. By setting the drawing tension to 0.5 cN/dtex or more, the orientation is promoted by the drawing stress and the shrinkage difference between the two components is promoted, thereby narrowing the coil pitch. As a result, the elongation rate A is lowered, the yarn does not elongate even under the weft tension, the woven fabric is within the standard, and excellent stretchability is obtained when it is made into a woven fabric. By setting the drawing tension to 1.1 cN/dtex or less, an excessive decrease in the elongation rate A can be suppressed, and crimping and wrinkling of the fabric can be suppressed, which is preferable. In addition, stable reeling properties can be obtained without thread breakage during operation. A more preferable drawing tension is 0.7 cN/dtex to 1.0 cN/dtex.
The relaxation tension is preferably 0.1 cN/dtex to 0.3 cN/dtex. By setting the relaxation tension to 0.1 cN/dtex or more, stress is applied to the oriented and crystallized material by stretching, and the orientation progresses to promote the shrinkage difference between the two components, thereby narrowing the coil pitch. As a result, the elongation rate A is lowered, the yarn does not elongate even under the weft-stretching tension, and the yarn is within the standard width of the woven fabric, and good stretchability is obtained when the woven fabric is produced. By setting the relaxation tension to 0.3 cN/dtex or less, an excessive decrease in the elongation rate A can be suppressed, and grains and wrinkles in the fabric can be suppressed, which is preferable. In addition, stable reeling properties can be obtained without winding tightness in package formation during winding. A more preferred relaxation tension is 0.18 cN/dtex to 0.25 cN/dtex.

In addition, it is possible to control the difference in the degree of orientation between the two components by adjusting the heat setting temperature and the heat setting time, which are the heat setting conditions after stretching, and to set the elongation rate A within the desired range.

The heat setting temperature here is preferably 130°C to 180°C, more preferably 140°C to 165°C, as the temperature of the heating element (hot roll, hot plate, etc.) with the highest set temperature.

Moreover, it is preferable to set the heat setting time to 1.5×10 ⁻⁴ seconds to 3.5×10 ⁻⁴ seconds. By setting the heat setting time to 1.5×10 ⁻⁴ seconds or more, the orientation progresses and the contraction difference between the two components is promoted, thereby narrowing the coil pitch. As a result, the elongation rate A is lowered, the yarn does not elongate even under the weft tension, and the yarn falls within the specification of the woven fabric. By setting the heat setting time to 3.5×10 ⁻⁴ seconds or less, an excessive decrease in the elongation rate A can be suppressed, and grains and wrinkles of the fabric can be suppressed, which is preferable. In addition, stable reeling properties can be obtained without thread breakage during operation.
The polyester fiber of the present invention may be false twisted. False twisting methods include a spindle method, a three-axis twister method, a belt nip method, and the like. It is preferable to use a spindle method when it is desired to strengthen the crimp, and it is preferable to use a triaxial twister or belt nip, which are friction false twisting methods, when it is desired to reduce the production cost by increasing the processing speed. The heating method includes a contact type, a non-contact type hot plate, a high-temperature short heater, and the like.

A water jet loom, air jet loom, or rapier loom can be used for the weaving loom. Weaving with a water jet loom is preferable in terms of ease of weft insertion and weaving speed.

Relax heat treatment, intermediate setting, alkali weight loss dyeing, finishing setting, etc. can be performed after weaving. In the relaxation heat treatment, the processing temperature is preferably 80° C. or higher in order to overcome the binding force of the fabric and sufficiently develop the crimp.

A woven fabric composed of the polyester fiber of the present invention has an elongation rate in the weft direction of the fabric of 5% to 30%. When the elongation rate in the weft direction of the fabric is set to 5% or more, it is possible to follow the expansion and contraction of the skin during exercise of the human body, and a comfortable wear can be obtained. When the elongation rate in the weft direction of the fabric is set to 30% or less, a good product free from crimps and wrinkles can be obtained.

The weave width standard ratio of the fabric composed of the polyester conjugate fiber of the present invention is preferably within the range of ±4.0%. More preferably, it is in the range of ±2.0%.

The following evaluations were made for Examples and Comparative Examples.

(1) Intrinsic viscosity (IV)
0.8 g of a sample was dissolved in 10 mL of O-chlorophenol (OCP) with a purity of 98% or more, and the relative viscosity ηr was determined by the following formula using an Ostwald viscometer at a temperature of 25 ° C., and the intrinsic viscosity IV was calculated. .
ηr=η/η0=(t×d)/(t0×d0)
IV=0.0242ηr+0.2634
[η: viscosity of polymer solution, η0: viscosity of OCP, t: drop time of solution (seconds), d: density of solution (g/cm ³ ), t0: drop time of OCP (seconds), d0: OCP Density (g/cm ³ )]

(2) Fineness Using a measuring machine with a frame circumference of 1.0 m, 100 skeins were prepared from a fiber sample, and the value calculated by the following formula from the value weighed on a balance was used as the fineness.
Fineness (dtex) = skein weight (g) x 100

(3) Elongation rate <Elongation rate A at a load of 3.5% with respect to fineness>
・ Using a measuring machine with a frame circumference of 1.0 m, prepare two skeins for 10 times without tension ・ Apply a load of 3.5% to the fineness, and the sample length after 30 seconds ( After removing the load, apply a constant load of 100 g and measure the sample length (L1) after 30 seconds. Calculate the elongation rate A according to the following formula. Calculate the average value of the calculated values for the two samples. Elongation Rate A (%) = L0/L1 x 100
<Elongation rate B at a load of 18% with respect to fineness>
・Use a measuring machine with a frame circumference of 1.0m to prepare two skeins of 10 times without tension ・Apply a load of 18% to the fineness, and the sample length (L2) after 30 seconds After removing the load, apply a constant load of 100 g and measure the sample length (L1) after 30 seconds. Calculate the elongation rate B according to the following formula. Calculate the average value of the calculated values of the two samples. (%) = L2/L1 x 100

(4) Degree of Orientation Measured by laser Raman spectroscopy. The equipment and conditions are as follows.
・Equipment: T-64000 (Jobin Yvon/Atago Bussan)
・Conditions: Measurement mode; microscopic Raman objective lens; ×100
Beam diameter: 1 μm
Light source; Ar + laser/514.5 nm
Laser power: 5mW
Diffraction grating; Single1800gr/mm
Slit: 100mm
Detector; CCD/Jobin Yvon 1024×256
Sampling was performed so that the interface between the components was in the center when viewed from the surface of the single fiber, and the laser was focused on the central portion of each component in the fiber radial direction for measurement.

　The orientation was measured under polarized conditions. The degree of orientation was evaluated from the ratio of the Raman band intensities obtained under the parallel condition when the polarization direction coincided with the fiber axis and the vertical condition when the polarization direction was perpendicular to the fiber axis. Three arbitrarily selected single yarns were measured, and the average value was calculated.

The Raman band around 1615 cm ⁻¹ of polyester and copolymer-containing polyester is attributed to the C═C stretching vibration mode. The vibration direction is the mode parallel to the molecular chain. Since Raman scattering is strongly obtained when the vibration direction of the molecular chain and the polarization direction of the incident light match, the scattering intensity of this vibration mode changes in correlation with the degree of orientation.

The degree of orientation was obtained by dividing the intensity under the condition of polarization parallel to the fiber axis (I1615 parallel) by the intensity under the condition of polarization perpendicular to the fiber axis (I1615 perpendicular).
Orientation=I1615 parallel/I1615 perpendicular

(5) Elasticity Elongation Ratio The elastic elongation ratio was determined according to JIS L1013 (2010) Section 8.11 C method (simple method).

(6) Weave width standard comparison (%)
The weaving width was measured according to ISO22198 (2006). The weave width standard comparison was calculated by the following formula.
Weaving width standard comparison (%) = (standard width - measured weaving width) / measured weaving width x 100

(7) Weft direction elongation of fabric (%)
It was measured by the elongation rate A method (constant rate elongation method) of JIS L-1096. The elongation rate in the weft direction was measured at three points or more, and the average value was calculated.

(8) Fabric evaluation A. Stretchability According to JIS L1096 (2010) Section 8.16.1 Method A (constant speed stretching method), the stretching rate in the weft direction of the fabric was determined. It was evaluated in the following three grades, and S and A were considered to have good stretchability.
S: Elongation rate of 10% or more A: Elongation rate of 5% or more and less than 10% C: Elongation rate of less than 5%

B. Softness The fabric obtained was inspected by a skilled inspector and evaluated for softness by touch. Passing levels are S and A.
S: Very good softness A: Good softness C: Poor softness

C. Grains and Wrinkles The resulting woven fabrics were inspected by a skilled inspector and visually evaluated for the occurrence of grains and wrinkles. Passing levels are S and A.
S: Very good without wrinkles and wrinkles A: Pass level with some wrinkles and wrinkles C: Fail level with many wrinkles and wrinkles

Example 1
(Weft production)
Polytrimethylene terephthalate (PTT) with an intrinsic viscosity of 1.44 as a core component, polyethylene terephthalate (PET) with an intrinsic viscosity of 0.51 as a sheath component, and both the PTT polymer and the PET polymer were extruded at 260°C using an extruder. After being melted at 280° C., it was weighed by a pump and set at a spinning temperature of 275° C. and flowed into the spinneret while maintaining the temperature. The composite ratio of the PTT component and the PET component was set to 50/50, and the mixture was flowed into a spinneret for eccentric core-sheath type composite fibers having 48 ejection holes. Each polymer merged inside the die to form an eccentric core-sheath composite shape in which the PTT polymer was included in the PET polymer, and was discharged from the die.

The yarn discharged from the spinneret was spun and drawn using the melt spinning equipment shown in FIG. That is, the conjugate fiber discharged from the spinneret 1 is cooled by the yarn cooling blower 2 so that the cooling start point is 79 mm, and the oil agent is applied by the oil agent applying device 3 in an amount of 0.8% by weight based on the weight of the fiber. After pre-entangling with an air pressure of 0.03 MPa by a pre-entangling device 4, it is taken up by a first hot roller (1HR) 5 heated to a temperature of 60° C. at a speed of 1070 m/min, and is not wound once. The film was drawn at a speed of 3780 m/min to a second hot roller (2HR) 6 heated to a temperature of 155° C., stretched at a draw ratio of 3.5, and heat-set for 2.5×10 ⁻⁴ seconds. Furthermore, the main entangling device 7 provides the main entanglement at an air pressure of 0.15 MPa, and the two godet rollers (the third godet roller (3GR) 8, the fourth godet roller (4GR) at a speed of 3704 m / min (relaxation rate 2.0 times). ) and 9), and then wound around a package 10 at a package winding speed of 3675 m/min to obtain a composite fiber of 56 dtex-48 filaments. The stretching tension was between 1 HR and 2 HR, and the relaxation tension was between 2 HR and 3 GR. As a result of measurement using a tension measuring device (manufactured by INTEC, model number IT-NP), the stretching tension was 0.86 cN / dtex, and the relaxation tension was was 0.19 cN/dtex. The fiber properties of this polyester fiber were as shown in Table 1.

Using the obtained polyester fibers for warp and weft, a plain weave fabric with a standard width of 185 cm, a density of 152×122 threads/2.54 cm, and a basis weight of 122 g/m ² was woven using a water jet loom. The width of the obtained woven fabric was measured, and the result of calculating the woven width standard comparison was as shown in Table 1, and the width was good. The resulting fabric was subjected to a relaxation heat treatment in an open soaper at a processing temperature of 95°C, after drying, intermediate set at 180°C and dyed at 120°C. After that, it was finished and set by a pin tenter method with dry heat at 160°C. The obtained woven fabric was very excellent in softness and stretchability, and the quality of the woven fabric was good without grains or wrinkles.

Examples 2 and 3, Comparative Examples 1 and 2
A polyester fiber was obtained in the same manner as in Example 1 except that the heat setting time at 2HR was changed as shown in Table 1. The fiber properties obtained are shown in Table 1. The woven fabrics obtained in Examples 2 and 3 were excellent in softness, and the stretchability and quality of the woven fabric obtained in Example 1 were inferior but good. .

In Comparative Example 1, the heat setting time was short, the elongation rate A was as high as 93%, the weft yarn was elongated due to the tension of weft beating, and the obtained fabric did not have sufficient stretchability.

In Comparative Example 2, the heat setting time was long, the elongation rate A was as low as 59%, and the weave density was increased due to the heat treatment due to excessive coiling, and the resulting fabric had many grains and wrinkles.

Examples 4-7
A polyester fiber was obtained in the same manner as in Example 1 except that the 1HR speed was changed to 945 to 1260 m/min and the draw ratio was changed as shown in Table 2 to change the drawing tension and the relaxation tension. . As a result of measurement using a tension measuring device, the stretching tension was 0.5 to 1.1 cN/dtex, the relaxation tension was 0.10 to 0.30 cN/dtex, and the obtained fiber properties are shown in Table 1. , Examples 5 and 6, the obtained fabrics were very excellent in softness and stretchability, and the quality of the fabrics was good without crimps or wrinkles.

In Example 4, the softness and stretchability of the obtained fabric were very excellent, but the quality of the fabric was at an acceptable level although there were some grains and wrinkles.

In Example 7, the resulting woven fabric was excellent in softness, had no wrinkles and wrinkles, and was inferior to Example 1, but had good stretchability.

Comparative Examples 3, 4, 5
In Comparative Example 3, a polyester fiber was obtained in the same manner as in Example 1 except that the 1HR speed was changed to 1400 m/min and the draw ratio was changed to 2.7 times, thereby changing the drawing tension and the relaxation tension. . As a result of measurement with a tension measuring device, the stretching tension was 0.4 cN/dtex, the relaxation tension was 0.08 cN/dtex, the elongation rate A was as high as 96%, and the obtained fabric had sufficient stretchability. I couldn't.

In Comparative Example 4, a polyester fiber was obtained in the same manner as in Example 1 except that the 1HR speed was changed to 2360 m/min and the draw ratio was changed to 1.6 times, thereby changing the drawing tension and the relaxation tension. . As a result of measurement with a tension measuring device, the stretching tension was 0.2 cN/dtex, the relaxation tension was 0.06 cN/dtex, the elongation rate A was as high as 98%, and the obtained fabric had sufficient stretchability. I couldn't.

In Comparative Example 5, a polyester fiber was obtained in the same manner as in Example 1 except that the 1HR speed was changed to 840 m/min and the draw ratio was changed to 4.5 times, thereby changing the drawing tension and the relaxation tension. . As a result of measurement with a tension measuring device, the stretching tension was 1.2 cN/dtex, the relaxation tension was 0.35 cN/dtex, and the elongation rate A was as low as 54%. rice field.

Comparative Examples 6 and 7
Comparative Example 6 was performed in the same manner as in Example 1 except that the relaxation tension was changed by changing the 3GR speed and 4GR speed to 3760 m/min (relaxation rate 0.5 times) and the package winding speed to 3730 m/min. A polyester fiber was obtained. As a result of measurement with a tension measuring device, the relaxation tension was 0.36 cN/dtex, the elongation rate A was as low as 56%, and the obtained woven fabric had many grains and wrinkles.

Comparative Example 7 was performed in the same manner as in Example 1 except that the relaxation tension was changed by changing the 3GR speed and 4GR speed to 3590 m/min (relaxation rate 5.0 times) and the package winding speed to 3560 m/min. A polyester fiber was obtained. As a result of measurement with a tension measuring device, the relaxation tension was 0.07 cN/dtex, the elongation rate A was as high as 95%, and the obtained fabric did not have sufficient stretchability.

Example 8
A polyester fiber was obtained in the same manner as in Example 1, except that the core component was changed to polybutylene terephthalate (PBT) having an intrinsic viscosity of 1.30. Table 3 shows the evaluation results of the properties of the obtained polyester fiber. The resulting woven fabric was excellent in softness, had no wrinkles and wrinkles, and was inferior to Example 1, but had good stretchability.

Examples 9-11
Polyester fibers were obtained in the same manner as in Example 1, except that the number of discharge holes of the spinnerets for eccentric sheath-core composite fibers was changed to 36, 24 and 72, respectively.
In Examples 9 and 10, the elastic force of the coil was increased by increasing the fineness of the single yarn, and the obtained woven fabrics were excellent in stretchability, and wrinkles and wrinkles were not observed. Example 10 was inferior to Example 1, but had good softness.
Example 11 was inferior to Example 1, but had good stretchability, excellent softness, and did not show crimps or wrinkles.

Example 12
A polyester fiber was obtained in the same manner as in Example 1, except that the side-by-side type conjugate fiber spinneret was used and a bimetallic shape was used. The resulting woven fabric was inferior to that of Example 1, but had good stretchability, excellent softness, and good fabric quality with no crimps or wrinkles.

Example 13
The polyester fiber obtained in Example 1 was heated to a secondary set heater temperature of 180° C. using a false twisting machine (the twisting part heater is a contact type, the secondary set heater is a non-contact type, and the processing mechanism is a friction type). , a two-stage heater false twisting process was performed at a processing speed of 500 m/min and a processing ratio of 1.04 times to obtain a false twisted yarn of 55 dtex-48 filaments.
Weaving was carried out in the same manner as in Example 1 using the false twisted yarn as the weft yarn with a water jet loom so as to have a basis weight of 122 g/m ² . The obtained woven fabric was very excellent in softness and stretchability, and the quality of the woven fabric was at an acceptable level although there were some grains and wrinkles.

Comparative example 8
A polyester fiber was obtained in the same manner as in Example 1, except that the core component was changed to polyethylene terephthalate having an intrinsic viscosity of 0.62.
In Comparative Example 8, the elongation rate A was as high as 97.9%, and the obtained woven fabric did not have stretchability.

The polyester fiber of the present invention has excellent soft stretchability and can provide high-quality stretch fabrics free from crimps and wrinkles.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application (Japanese Patent Application No. 2021-181653) filed on November 8, 2021, the contents of which are incorporated herein by reference.

1: Spinneret 2: Yarn cooling blower 3: Lubricating device 4: Pre-entangling device 5: First hot roller 6: Second hot roller 7: Main entangling device 8: Third godet roller 9: Fourth godet roller 10: Package 11: Contact roller A: Weft B: Warp C: Coil pitch

Claims (5)

A polyester fiber composed of two types of polyester polymers, with an elongation rate A of 60% to 90% at a load of 3.5% relative to the fineness. The difference in elongation rate between the elongation rate A at a load of 3.5% with respect to the fineness and the elongation rate B at a load of 18.0% with respect to the fineness is 5.0% to 25.0%. The polyester fiber according to claim 1. The polyester fiber according to claim 1 or 2, which has a single filament fineness of 1.5 dtex or less. The polyester fiber according to claim 1 or 2, wherein the difference in the degree of orientation of the two types of polyester polymers in the cross section of the fiber is 2.5 to 4.5. A woven fabric composed of the polyester fiber according to claim 1 or 2, wherein the elongation rate in the weft direction of the fabric is 5% to 30%.

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