Fused false-twisted yarn and knitted or woven fabric

Abstract

To provide a stretch fusion false-twisted yarn and knitted fabric having excellent cool feeling and surface quality even after long-term repeating washing.SOLUTION: A fusion false-twisted yarn comprises eccentric sheath-core composite fibers composed of a polymer A and a polymer B which are two kinds of polyethylene terephthalate components, in which the difference of a weight-average molecular weight MwA of the polymer A and a weight-average molecular weight MwB of the polymer B, (MwA-MwB), is 2,000-15,000.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a stretch-fused false-twisted yarn and a woven or knitted fabric having excellent coolness and surface quality even in long-term repeated washing use.

Background Art

[0002] Conventionally, as a synthetic fiber material having a cool feeling, a fused false-twisted yarn using a thermoplastic filament such as polyethylene terephthalate fiber has been known.

[0003] For example, Patent Document 1 discloses a method for producing a fused false-twisted yarn in which a partially oriented polyester undrawn yarn is false-twisted under specific false-twisting conditions to continuously fuse single filaments partially or in the length direction. However, in such a conventional fused false-twisted yarn, no crimping occurs in the fused portion, and high stretchability cannot be imparted to the woven or knitted fabric.

[0004] Further, Patent Document 2 proposes a fused false-twisted yarn in which polytrimethylene terephthalate and a second component polymer are composite-spun in a side-by-side type or an eccentric sheath-core type. In this method, stretchability can be imparted to the woven or knitted fabric. However, when the second component is other than polytrimethylene terephthalate, the melting point is different from that of polytrimethylene terephthalate. To fuse two types of polymers, it is necessary to set the false-twisting temperature to the polymer having a higher melting point. Therefore, the fusing strength has to be increased, and coil crimping does not occur in the fused portion, so there is a problem that the quality of the woven or knitted fabric deteriorates. On the other hand, even when the second component is also polytrimethylene terephthalate, due to the low Young's modulus characteristic of polytrimethylene terephthalate, when an external force is applied by repeated washing, the fused portion is likely to come loose and the cool feeling is lost.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] The present invention relates to a stretch-fused false-twisted yarn and a woven or knitted fabric that overcome the problems of the prior art and have excellent coolness and surface quality even after long-term repeated washing use. [Means for Solving the Problems]

[0007] To solve the above problems, the fused false-twisted yarn of the present invention has the following configuration. That is, It is composed of eccentric core-sheath composite fibers made of two polyethylene terephthalate components, polymer A and polymer B, and the weight average molecular weight Mw of the polymer A A and the weight average molecular weight Mw of the polymer B B The difference (Mw A -Mw B ) is 2,000 to 15,000, the average length of the fused part is 3 to 30 mm, and the average number of the fused parts is 5 to 100 / m It is a fused false-twisted yarn characterized by being

[0008] The woven or knitted fabric of the present invention has the following configuration. That is,

[0009] A woven or knitted fabric containing 20% or more of the above fused false-twisted yarn by weight ratio.

[0010] In the cross-section of the eccentric core-sheath composite fiber of the fused false-twisted yarn of the present invention, the polymer A component is completely covered by the polymer B component, and the ratio S / D of the minimum thickness S of the polymer B component covering the polymer A component to the fiber diameter D is 0.01 to 0.2, and it is preferable that the length of the part within 1.10 times the thickness from the minimum thickness S is 1 / 3 or more of the peripheral length of the entire eccentric core-sheath composite fiber. [Effects of the Invention]

[0011] By using the heat-fused false-twisted yarn defined in the present invention, it is possible to provide a stretch woven or knitted fabric having excellent cool feeling and surface quality even in long-term repeated washing use.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0013] Hereinafter, the present invention will be described in detail together with preferred embodiments.

[0014] And in the above two polyethylene terephthalate components, the weight average molecular weight Mw of polymer A A and the weight average molecular weight Mw of polymer B B The difference (Mw A -Mw B) That is, when the difference in weight-average molecular weight is 2,000 to 15,000, the fiber greatly curves toward the high weight-average molecular weight side after heat treatment, and by the continuity of this, it takes a three-dimensional coil structure. Therefore, this structure stretches and contracts like a spring, and excellent stretchability can be obtained after false twisting. Also, in order to achieve stretchability in woven and knitted fabrics using conventional fused false-twisted yarns, there was a problem that the morphological difference between the crimped form of the non-fused part and the non-crimped form of the fused part became large, resulting in a worm-eaten texture in the woven and knitted fabrics. However, in the fused false-twisted yarn of the present invention, by adopting the above polymer configuration, coil crimping is also exhibited in a part of the fused part, making it possible to obtain a woven and knitted fabric with excellent surface quality. If the difference in weight-average molecular weight is less than 2,000, coil crimping cannot be exhibited in the fused part of the fused false-twisted yarn, and the quality of the woven and knitted fabric deteriorates. When the difference in weight-average molecular weight exceeds 15,000, yarn breakage during spinning frequently occurs, and stable production cannot be achieved. Here, the preferable difference in weight-average molecular weight is 4,000 to 13,000.

[0015] Also, as for Mw A the range is preferably 20,000 to 28,000, and as for Mw B the range is preferably 12,000 to 20,000. When each is within this range, the spinnability of the eccentric core-sheath composite fiber and the stretchability of the woven and knitted fabric become good, so it is preferable.

[0016] Note that the weight-average molecular weight in the present invention is measured by preparing a measurement solution in which 2.0 mg of the composite fiber is completely dissolved in 2.5 cm 3 of tetrahydrofuran, and performing a gel permeation chromatography test using polystyrene as the standard substance. For the gel permeation chromatography (GPC) tester, for example, "TOSO GMHHR-H(S)HT" manufactured by Tosoh Corporation is used.

[0017] In addition, as the polyethylene terephthalate component used in the present invention, a polyester in which terephthalic acid is the main acid component and ethylene glycol is the main glycol component, and 90 mol% or more is composed of repeating units of ethylene terephthalate can be used. Further, within a range that does not inhibit the effects of the present invention, it may contain a copolymerizable component capable of forming other ester bonds. Here, examples of copolymerizable compounds include dicarboxylic acids such as isophthalic acid, cyclohexanedicarboxylic acid, adipic acid, dimer acid, sebacic acid, and sulfoisophthalic acid, diol components, or oxycarboxylic acid components.

[0018] In addition, the polyethylene terephthalate in the present invention may contain one or more of titanium oxide, microporous forming agent, cationic dyeable agent, anti-coloring agent, heat stabilizer, flame retardant, fluorescent brightening agent, matting agent, coloring agent, antistatic agent, moisture absorbent, antibacterial agent, inorganic fine particles, etc. as required within a range that does not impair the object of the present invention.

[0019] In addition, the fiber cross-section of the eccentric core-sheath composite fiber used in the present invention has a composite cross-section formed by joining two different polymers, and two polymers with different polymer properties exist in a state where they are joined without substantial separation, and it is preferably an eccentric core-sheath type in which the B component completely covers the A component.

[0020] Here, the eccentricity referred to in the present invention means that the position of the center of gravity of the polymer A component in the composite fiber cross-section is different from the center of the composite fiber cross-section. Hereinafter, it will be specifically described with reference to FIG. 2. In FIG. 2, the horizontal hatching is the polymer B component, the 30deg hatching (diagonal line rising to the upper right) is the polymer A component, the center of gravity of the polymer A component in the composite fiber cross-section is the center of gravity point a, and the center of gravity of the composite fiber cross-section is the center of gravity point C.

[0021] In the eccentric core-sheath composite fiber used in the present invention, due to the fact that the center of gravity point a and the center of gravity point C of the composite fiber cross-section are separated (eccentric), the fiber greatly curves towards the high weight-average molecular weight side after heat treatment. In this way, since the high weight-average molecular weight component shrinks relatively more strongly than the low weight-average molecular weight component, the eccentric core-sheath composite fiber continues to curve in the fiber axis direction. As a result, the eccentric core-sheath composite fiber takes on a three-dimensional coil structure and exhibits good crimp. Here, the greater the separation of the center of gravity positions, the better the crimp is exhibited and good stretch performance can be obtained. In the fused false-twisted yarn of the present invention, since the polymer B component completely covers the polymer A component, the fused state can be made stronger and excellent cool feeling can be maintained even in long-term repeated washing use, which is preferable.

[0022] Also, in the fused false-twisted yarn of the present invention, if the ratio S / D of the minimum thickness S of the B component covering the polymer A component to the fiber diameter (diameter of the composite fiber) D is 0.01 to 0.2, more excellent stretch performance and a strong fused form can be obtained, which is preferable. More preferably, it is 0.02 to 0.08.

[0023] It will be described in more detail using the fiber cross-section shown in FIG. 3. Here, the thinnest part of the B component in the core-sheath composite fiber is the minimum thickness S.

[0024] Furthermore, it is preferable that the length of the part with a thickness within 1.10 times the minimum thickness S (hereinafter sometimes referred to as the "minimum thickness part") occupies 1 / 3 or more of the entire peripheral length of the composite fiber. This means that the polymer A component exists along the contour of the fiber. Compared with the conventional eccentric core-sheath composite fiber with the same area ratio, in the present invention, the center of gravity positions of the respective components are more separated in the fiber cross-section, forming fine coils and exhibiting good crimp. More preferably, good stretch performance can be obtained by setting the length of the part with a thickness within 1.10 times the minimum thickness S to 2 / 5 or more of the entire peripheral length of the fiber.

[0025] The measuring methods of the minimum thickness S and the fiber diameter D are shown below.

[0026] Embed a multifilament composed of eccentric core-sheath composite fibers in an embedding agent such as an epoxy resin, and take an image at a magnification at which 10 or more fibers can be observed with a transmission electron microscope (TEM) in a cross-section perpendicular to the fiber direction. At this time, when metal staining is performed, the contrast at the junction between the polymer A component and the polymer B component can be clarified by utilizing the staining difference between polymers. The presence of the junction confirms that the eccentric core-sheath composite fiber is composed of two components. For the cross-sections of 10 single filaments of eccentric core-sheath composite fibers randomly extracted from the same image in each of the taken images, a circle circumscribing the cross-section is set, and the measured value of the diameter of the circumscribing circle corresponds to the fiber diameter D referred to in the present invention. The circle circumscribing the cross-section here means a true circle that circumscribes at two or more points on the cross-section perpendicular to the fiber axis from the two-dimensionally taken image, and the circumscribing circle diameter means the diameter of the true circle. Also, using the image in which the fiber diameter D was measured, for 10 or more fibers, the measured value of the minimum thickness of the polymer B component covering the polymer A component corresponds to the minimum thickness S referred to in the present invention. Furthermore, for these fiber diameters D and minimum thicknesses S, they are measured with the unit of μm and rounded off at the third decimal place and below. For the 10 images taken in the above operations, obtain the measured values and the simple arithmetic mean value of the ratio (S / D). In addition, using the above-mentioned taken images and the image analysis software "WinROOF2015" (manufactured by Mitani Shosha Co., Ltd.), after obtaining the area of the entire fiber and the areas of the A component and the B component, the center of gravity of the specific gravity and the area ratio can be obtained.

[0027] Also, it is preferable that the length of the portion with a thickness within 1.10 times the minimum thickness S is 1 / 3 or more of the peripheral length of the entire fiber. More preferably, by making the length of the portion with a thickness within 1.05 times the minimum thickness S be 2 / 5 or more of the peripheral length of the entire fiber, good stretch performance can be obtained. For this length as well, it can be measured by the same measurement method as described above.

[0028] In order to enhance the stretch properties of the fused false-twisted yarn of the present invention, the ratio of the two components is preferably in the range of polymer A component: polymer B component = 70:30 to 30:70 (area ratio), and more preferably in the range of 65:35 to 45:55.

[0029] The fused false-twisted yarn of the present invention is a false-twisted yarn having a partially fused portion. By performing false-twisting processing on the eccentric core-sheath composite fiber at a high temperature, a fused portion can be formed in a part of the processed yarn, and a cool feeling can be imparted to the woven or knitted fabric.

[0030] The cross-section of the fiber of the fused false-twisted yarn of the present invention can be selected from those having arbitrary shapes such as round, triangular, flat, hexagonal, L-shaped, T-shaped, W-shaped, octalobed, dogbone-shaped, etc., polygonal, diverse, hollow-shaped, etc., but a round shape is preferred for enhancing stretch properties.

[0031] In terms of imparting stretchability and a cool feeling to the woven or knitted fabric, the fineness of the fused false-twisted yarn of the present invention is preferably 30 to 330 dtex, and the single-filament fineness is preferably 0.5 to 10 dtex.

[0032] It is also possible to use the fused false-twisted yarn of the present invention by combining or mixing two or more with other polyethylene terephthalate fibers (which may be the same eccentric core-sheath composite fiber). In the mixed yarn of the eccentric core-sheath composite fiber used in the present invention and other fibers, the ratio of the eccentric core-sheath composite fiber is preferably in the range of 20 to 80% by mass.

[0033] The woven or knitted fabric of the present invention can impart a cool feeling to the woven or knitted fabric by containing at least 20% or more of the fused false-twisted yarn by weight. If it is less than 20%, the woven or knitted fabric will have insufficient cool feeling. Also, in order to maintain the cool feeling, the average length of the fused portion of the fused false-twisted yarn of the present invention is 3 to 30 mm, and the average number of fused portions is 5 to 100 / m is ru. Good preferably 5 to 20 mm, 10 to 50 / m is.

[0034] In order to maintain the sense of coolness even after repeated washing, it is preferable that the average length of the fused part after 20 washes is 3 mm or more.

[0035] Also, it is preferable that the elongation rate of the knitted or woven fabric of the present invention under a load of 1.5 kgf (14.7 N) in at least one of the warp direction or the weft direction is 10% or more, and more preferably 15% or more. Thereby, even in a wide range of clothing applications such as jackets, suits, bottoms, uniforms, shirts, school clothes, sports clothes, skirts, and innerwear, it is possible to maintain the sense of coolness even after repeated washing, which is preferable.

[0036] Next, a preferred method for producing the fused false-twisted yarn of the present invention will be described.

[0037] It is preferable to precisely control the sheath thickness and the peripheral length of the thin skin part of the eccentric core-sheath composite fiber used in the present invention. For the spinneret, a method using a distribution plate exemplified in JP-A-2011-174215, JP-A-2011-208313, and JP-A-2012-136804 is preferably used. When producing a composite yarn having an eccentric core-sheath type cross-section using a conventionally known composite spinneret, it is often very difficult to precisely control the core gravity position and the sheath thickness. For example, when the sheath thickness becomes thin and the core component is exposed, it may cause a decrease in fusibility during long-term repeated washing and use. Conversely, when the sheath thickness becomes thick, the problem may occur that the stretch performance decreases because the expression of crimping decreases.

[0038] The eccentric core-sheath composite fiber used in the present invention is preferably wound up as an undrawn yarn or a highly oriented undrawn yarn at a spinning speed of 1,500 to 3,800 m / min.

[0039] The eccentric core-sheath composite fiber used in the present invention preferably completely covers the polymer A component with the polymer B component as shown in FIG. 2. By setting the cross-section defined in the present invention, it is possible to suppress the discharge line bending (neining phenomenon) caused by the flow velocity difference between the two polymers during die extrusion. In addition, in the case of the conventional simple laminated structure (bimetal structure), a difference occurs in the stress balance applied to each polymer during the thinning on the spun yarn after die extrusion, resulting in uneven elongation deformation, which appears as uneven fineness and may increase U%. This tendency is very prominent in combinations of polymers with large viscosity differences and molecular weight differences. However, in the present invention, since one polymer covers the other, the stress balance is equalized within the fiber cross-section, and uneven fineness can be suppressed.

[0040] Subsequently, the heat-set false-twisted yarn used in the present invention can be obtained by processing the above eccentric core-sheath composite fiber under high-temperature false-twisting conditions. As the false-twisting conditions, any false-twisting conditions can be selected. In the case of a contact heater, the false-twisting temperature is preferably 180 to 235°C. More preferably, it is 210 to 230°C. Any of a spindle type, a friction disk type, or a belt nip type can be used for the twister. Regarding the false-twisting number, it is preferable to set it in the range where the false-twisting coefficient (false-twisting number (T / M) × fineness (dtex) 0.5 ) is 15,000 to 33,000 in terms of being able to impart strong crimp and heat setting.

[0041] In addition, in order to further improve the cooling feeling, low-ratio hot stretching can be performed before false-twisting to impart thick and thin parts to the fiber. Also, there is no problem in heat setting with a heater after false-twisting in order to reduce the residual torque. Regarding the yarn processing speed, the faster it is, the higher the productivity, which is preferable. However, considering the stable processability, 100 to 800 m / min is preferable.

[0042] In the woven or knitted fabric using the false-twist fused yarn of the present invention, in the woven fabric, any weave such as plain, twill, satin, Amundsen, double weave, etc. can be selected. As the knitting structure, any structure such as single jersey, smooth, half, double raschel, etc. can be selected. The thus obtained woven or knitted fabric of the present invention has sufficient stretch performance, and excellent cool feeling and surface quality can be obtained even in long-term repeated washing and use. This woven or knitted fabric is suitably used for a wide range of clothing applications such as jackets, suits, bottoms, uniforms, shirts, student clothing, sportswear, skirts, and innerwear.

Example

[0043] The following examples are given to specifically describe the false-twist fused yarn and the woven or knitted fabric of the present invention. The following evaluations were performed on the examples and comparative examples.

[0044] (1) Measurement of the weight-average molecular weight of the thermoplastic resin As the gel permeation chromatography (GPC) tester, “TOSO GMHHR-H(S)HT” manufactured by Tosoh Corporation was used.

[0045] (2) Denier Using a measuring machine with a frame circumference of 1.0 m, cops for 100 turns were prepared, and the denier was measured according to the following formula.

[0046] Denier (dtex) = weight of cops for 100 turns (g) × 100 (3) Crimp ratio The yarn was wound 10 times around a measuring machine with a circumference of 0.8 m under a tension of 90 mg / dtex, then skeined, suspended from a rod less than 2 cm in length, and left for approximately 24 hours. The skein was wrapped with gauze, heat-treated in hot water at 90 °C for 20 minutes under a non-tension state, then suspended from a rod less than 2 cm in length and left for approximately 12 hours. One end of the skein after standing was hooked, an initial load and a measurement load were applied to the other end, and it was suspended in water and left for 2 minutes. At this time, the initial load (g) = 2 mg / dtex, the measurement load (g) = 90 mg / dtex, and the water temperature = 20 ± 2 °C. The inner length of the suspended skein was measured and designated as L. Furthermore, it was left for 2 minutes with only the initial load excluding the measurement load, and the inner length of the suspended skein was measured and designated as L1. The crimp was obtained by the following formula, and this operation was repeated 5 times and the average value was obtained.

[0047] Crimp ratio (%) = {(L - L1) / L} × 100 (4) Elongation at break In accordance with Method B described in JIS L 1096 (2010), the elongation at break under a load of 1.5 kgf (14.7 N) was measured. This elongation at break was used as a measure of stretchability.

[0048] (5) Average length and number of fused parts Observation was carried out with an optical microscope (VHX-2000 manufactured by KEYENCE CORPORATION), and the average length and number of fused parts per 1 m of the yarn were measured. This operation was repeated 5 times and the average value was obtained.

[0049] Regarding the average length and number of fused parts after repeated washing, the fused false-twisted yarn was carefully removed so that the fused parts would not break from the woven or knitted fabric. In the repeated washing process, the woven or knitted fabric was subjected to cycle washing once in a two-tank washing machine at a liquid temperature of 40 °C, a washing time of 5 minutes, rinsing at 30 °C for 2 minutes twice, and dehydration for 30 seconds. "Attack" (registered trademark) manufactured by Kao Corporation was used as the detergent at 1 g / L, the liquid volume was 40 L, and the combined weight of the test fabric and the guiding fabric, which was a cotton cloth, was 830 g. After repeating this washing operation 20 times, the above evaluation was carried out. (6) Cooling sensation In a knitted or woven fabric that has undergone the same repeated laundering process as in (5), the fabric was evaluated in four grades by sensory evaluation: extremely excellent cool feeling, excellent cool feeling, slightly insufficient cool feeling, and insufficient cool feeling. The result was the one close to the average of the evaluations of 10 randomly selected people. (7) Surface quality In a knitted or woven fabric that has undergone the same repeated laundering process as in (5), the fabric was evaluated in four grades by sensory evaluation: extremely excellent surface quality, excellent surface quality, presence of creases on the surface, and presence of worm-eaten holes on the surface. The result was the one close to the average of the evaluations of 10 randomly selected people.

[0050] [Example 1] Polyethylene terephthalate with a weight average molecular weight of 25,000 was used as the polymer A component, and polyethylene terephthalate with a weight average molecular weight of 15,000 was used as the polymer B component. The weight composite ratio of the polymer A component and the polymer B component was 50 / 50, and it was introduced into a spinneret for eccentric core-sheath composite fibers with 24 discharge holes. Each polymer merged inside the spinneret to form an eccentric core-sheath composite form in which the polymer of the polymer A component was included in the polymer of the polymer B component, and was spun from the spinneret at a spinning speed of 2,800 (m / min) to obtain a highly oriented undrawn yarn with a fineness of 125 dtex, 36 filaments, and an elongation of 145%. In the spinning of Example 1, a spinneret of the distribution plate type was used such that the eccentric core-sheath composite fiber shown in FIG. 1 was obtained. The S / D in the fiber cross-section was 0.02, and the length of the minimum thickness part occupied 40% of the peripheral length of the entire eccentric core-sheath composite fiber.

[0051] Next, the above highly oriented undrawn yarn was fed from the feed roller using a friction false twisting machine (ATF12: manufactured by TMT Machinery Co., Ltd.), and false twisting was performed at a processing speed of 400 m / min, a draw ratio of 1.5 times, a heater temperature of 220 °C, and a false twist coefficient of 28,000 to obtain a fused false twisted yarn with a fineness of 84 dtex, a crimp ratio of 38%, an average length of the fused part of 15.3 mm, and a number of fusions of 24.1 per meter.

[0052] Subsequently, using the above yarns as warp and weft, plain weaving was performed on an air-jet loom to obtain a woven fabric. Next, the obtained woven fabric was subjected to continuous scouring at 98°C, liquid flow relaxation at 120°C, intermediate setting at 180°C, dyeing at 130°C, and finishing setting at 160°C, resulting in a product with a processing density (warp: 95 threads / 2.54 cm, weft: 90 threads / 2.54 cm). The elongation rates of the obtained fabric were 15.5% in the warp direction and 20.4% in the weft direction, showing excellent stretchability. Also, after 20 washes, the average length of the fused parts was 15.1 mm, and the number of fused parts was 22.9 pieces / m. It was a stretch fabric with excellent coolness and fabric quality even after long-term repeated washing and use. The evaluation results of the characteristics of the eccentric core-sheath composite fiber, the fused false-twisted yarn, and the fabric are shown in Table 1.

[0053] [Example 2] Spinning was carried out in the same manner as in Example 1, except that polyethylene terephthalate with a weight average molecular weight of 19,000 was used as the Polymer A component, and a high-orientation undrawn yarn with a fineness of 125 dtex, 36 filaments, and an elongation of 142% was obtained. The S / D in the fiber cross-section was 0.1, and the length of the minimum thickness part accounted for 35% of the peripheral length of the entire eccentric core-sheath composite fiber.

[0054] Next, using a friction false-twisting machine (ATF12: manufactured by TMT Machinery Co., Ltd.), the above high-orientation undrawn yarn was fed from the feed roller, and false-twisting was performed at a processing speed of 400 m / min, a draw ratio of 1.45 times, a heater temperature of 225°C, and a false-twist coefficient of 27,000, obtaining a fused false-twisted yarn with a fineness of 88 dtex, a crimp ratio of 30%, an average length of the fused parts of 17.2 mm, and a number of fused parts of 32.5 pieces / m.

[0055] Subsequently, weaving and dyeing processes were carried out in the same manner as in Example 1 to obtain a product. The elongation rates of the obtained fabric were 12.1% in the warp direction and 17.8% in the weft direction, showing excellent stretchability. Also, after 20 washes, the average length of the fused parts was 16.9 mm, and the number of fused parts was 28.0 pieces / m. It was a stretch fabric with excellent coolness and fabric quality even after long-term repeated washing and use. The evaluation results of the characteristics of the eccentric core-sheath composite fiber, the fused false-twisted yarn, and the fabric are shown in Table 1.

[0056] [Example 3] Spinning was carried out in the same manner as in Example 1 except that polyethylene terephthalate with a weight average molecular weight of 28,000 was used as the Polymer A component, and a highly oriented undrawn yarn with a fineness of 125 dtex, 36 filaments, and an elongation of 141% was obtained. The S / D in the fiber cross-section was 0.02, and the length of the minimum thickness portion occupied 40% of the peripheral length of the entire eccentric core-sheath composite fiber.

[0057] Next, the above highly oriented undrawn yarn was fed from the feed roller using a friction false twister (ATF12: manufactured by TMT Machinery Co., Ltd.), and false twisting was performed at a processing speed of 400 m / min, a draw ratio of 1.5 times, a heater temperature of 215 °C, and a false twist coefficient of 29,000, to obtain a fused false twisted yarn with a fineness of 84 dtex, a crimp ratio of 44%, an average length of the fused part of 8.6 mm, and a number of fusions of 11.2 per meter.

[0058] Thereafter, weaving and dyeing processes were carried out in the same manner as in Example 1 to obtain a product. The elongation rates of the obtained fabric were 21.2% in the warp direction and 25.6% in the weft direction, and it was extremely excellent in stretchability. Also, after 20 washes, the average length of the fused part was 8.0 mm and the number of fusions was 11.0 per meter. It was a stretch fabric that was excellent in cool feeling and fabric quality even in long-term repeated washing and use. The evaluation results of the characteristics of the eccentric core-sheath composite fiber, the characteristics of the fused false twisted yarn, the characteristics of the fabric, etc. are shown in Table 1. [Comparative Example 1] Polyethylene terephthalate with a weight average molecular weight of 32,000 was used as the Polymer A component, and polyethylene terephthalate with a weight average molecular weight of 15,000 was used as the Polymer B component. The weight composite ratio of the Polymer A component and the Polymer B component was 50 / 50, and spinning was carried out at a spinning speed of 2,800 m / min from a side-by-side spinneret with 24 orifices to obtain a highly oriented undrawn yarn with a fineness of 125 dtex, 36 filaments, and an elongation of 144%. However, the spinneret discharge bend was large and yarn breakage occurred frequently. The S / D in the fiber cross-section was 0, and the ratio of the length of the minimum thickness portion occupying the peripheral length of the entire eccentric core-sheath composite fiber was 0%.

[0059] Next, using a friction false-twisting machine (ATF12: manufactured by TMT Machinery Co., Ltd.), the above high-orientation undrawn yarn was fed from a feed roller, and false-twisting was performed at a processing speed of 400 m / min, a draw ratio of 1.5 times, a heater temperature of 220 °C, and a false-twist coefficient of 28,000, obtaining a fused false-twisted yarn with a fineness of 84 dtex, a crimp ratio of 48%, an average length of the fused part of 6.5 mm, and a number of fusions of 10.6 per meter.

[0060] Thereafter, weaving and dyeing processes were carried out in the same manner as in Example 1 to obtain a product. The elongation rates of the obtained fabric were 22.2% in the warp direction and 26.1% in the weft direction, showing excellent stretchability. After 20 washes, the average length of the fused part was 2.5 mm and the number of fusions was 9.0 per meter. In long-term repeated washing and use, the fused part came off, resulting in a lack of cool feeling and a fabric texture with a crepe pattern. The evaluation results of the properties of the eccentric core-sheath composite fiber, the properties of the fused false-twisted yarn, the properties of the fabric, etc. are shown in Table 1.

[0061] [Comparative Example 2] Spinning was carried out in the same manner as in Example 1 except that polyethylene terephthalate with a weight average molecular weight of 16,000 was used as the polymer A component, obtaining a high-orientation undrawn yarn with a fineness of 125 dtex, 36 filaments, and an elongation of 143%. The S / D in the fiber cross-section was 0.02, and the length of the minimum thickness part occupied 40% of the peripheral length of the entire eccentric core-sheath composite fiber. Next, using a friction false-twisting machine (ATF12: manufactured by TMT Machinery Co., Ltd.), the above high-orientation undrawn yarn was fed from a feed roller, and false-twisting was performed at a processing speed of 400 m / min, a draw ratio of 1.5 times, a heater temperature of 220 °C, and a false-twist coefficient of 28,000, obtaining a fused false-twisted yarn with a fineness of 84 dtex, a crimp ratio of 20%, an average length of the fused part of 17.4 mm, and a number of fusions of 18.1 per meter.

[0062] Thereafter, weaving and dyeing processes were carried out in the same manner as in Example 1 to obtain a product. The elongation rates of the obtained fabric were 12.1% in the warp direction and 13.8% in the weft direction. Also, the average length of the fused part after 20 washes was 17.0 mm, and the number of fusions was 17.5 per meter. Even in long-term repeated washing and use, the cooling feeling was excellent, but no coil crimp was imparted to the fused part, and it had a worm-eaten fabric texture. The evaluation results of the properties of the eccentric core-sheath composite fiber, the fused false-twisted yarn, the fabric properties, etc. are shown in Table 1.

[0063] [Comparative Example 3] Spinning was carried out in the same manner as in Example 1 except that polytrimethylene terephthalate with a weight average molecular weight of 25,000 was used as the polymer A component and polytrimethylene terephthalate with a weight average molecular weight of 15,000 was used as the polymer B component, and a high-orientation undrawn yarn with a fineness of 125 dtex, 36 filaments, and an elongation of 140% was obtained. The S / D in the fiber cross-section was 0.02, and the length of the minimum thickness part occupied 40% of the peripheral length of the entire eccentric core-sheath composite fiber. Next, using a friction false-twisting machine (ATF12: manufactured by TMT Machinery Co., Ltd.), the above high-orientation undrawn yarn was fed from the feed roller, and false-twisting was carried out at a processing speed of 400 m / min, a draw ratio of 1.5 times, a heater temperature of 210 °C, and a false-twist coefficient of 28,000 to obtain a fused false-twisted yarn with a fineness of 84 dtex, a crimp ratio of 41%, an average length of the fused part of 9.8 mm, and a number of fusions of 15.0 per meter.

[0064] Thereafter, weaving and dyeing processes were carried out in the same manner as in Example 1 to obtain a product. The elongation rates of the obtained fabric were 19.5% in the warp direction and 23.4% in the weft direction, and it was extremely excellent in stretchability. However, the average length of the fused part after 20 washes was 2.6 mm, and the number of fusions was 4.6 per meter. In long-term repeated washing and use, the fabric texture was excellent, but the fusions came off, and it was a fabric with insufficient cooling feeling. The evaluation results of the properties of the eccentric core-sheath composite fiber, the fused false-twisted yarn, the fabric properties, etc. are shown in Table 1.

[0065] [Comparative Example 4] The highly oriented undrawn yarn obtained by the same method as in Example 1 was fed from a feed roller using a friction false-twist machine (ATF12: manufactured by TMT Machinery Co., Ltd.), and false-twisting was performed at a processing speed of 400 m / min, a draw ratio of 1.5 times, a heater temperature of 160 °C, and a false-twist coefficient of 28,000, obtaining a false-twisted yarn with a fineness of 84 dtex, a crimp ratio of 41%, an average length of the fused part of 0 mm, and a number of fusions of 0 pieces / m. In addition, the S / D in the fiber cross-section of the above-mentioned highly oriented undrawn yarn was 0.02, and the length of the minimum thickness part occupied 40% of the peripheral length of the entire eccentric core-sheath composite fiber.

[0066] Thereafter, the false-twisted yarn was used as the warp, and for the weft, the fused false-twisted yarn obtained by the same method as the false-twisted yarn and Example 1 was used in an arrangement of 2:1, and weaving was performed into a plain fabric using an air-jet loom (the ratio of the fused false-twisted yarn was 16%). Next, the obtained woven fabric was subjected to continuous scouring at 98 °C, liquid flow relaxation at 120 °C, intermediate setting at 180 °C, dyeing at 130 °C, and finishing setting at 160 °C to obtain a product with a processing density (warp: 95 threads / 2.54 cm, weft: 90 threads / 2.54 cm). The elongation rate of the obtained fabric was 20.5% in the warp direction and 23.4% in the weft direction, and it was extremely excellent in stretchability. Also, after 20 washes, the average length of the fused part of the fused false-twisted yarn was 15.3 mm, and the number of fusions was 23.0 pieces / m, but the effect of the fused false-twisted yarn was small, and the fabric lacked a cool feeling. The evaluation results of the characteristics of the eccentric core-sheath composite fiber, the characteristics of the fused false-twisted yarn, the characteristics of the fabric, etc. are shown in Table 1.

[0067]

Table 1

Industrial Applicability

[0068] According to the present invention, by using the specified fused false-twisted yarn, it is possible to provide a stretch woven or knitted fabric having excellent cool feeling and surface quality even in long-term repeated washing use.

Explanation of Signs

[0069] 1 Polymer A component 2 Polymer B component a: Center of gravity point of polymer A component in the cross-section of the composite fiber C: Center of gravity point of the cross-section of the composite fiber S: Minimum thickness of polymer B component D: Fiber diameter

Claims

1. It consists of eccentric core-sheath composite fibers composed of two polyethylene terephthalate components, namely polymer A and polymer B, and the weight average molecular weight Mw of the polymer A Ａ and the weight average molecular weight Mw of the polymer B Ｂ The difference (Mw Ａ -Mw Ｂ ) is 2,000 to 15,000, the average length of the fused part is 3 to 30 mm, and the average number of the fused parts is 5 to 100 pieces / m. It is a fused false-twisted yarn characterized by this.

2. In the cross-section of the eccentric core-sheath composite fiber, the polymer A component is completely covered by the polymer B component, and the ratio S / D of the minimum thickness S of the polymer B component covering the polymer A component to the fiber diameter D is 0.01 to 0.2, and the length of the portion having a thickness within 1.10 times the minimum thickness S is 1 / 3 or more of the peripheral length of the entire eccentric core-sheath composite fiber. The heat-fused false-twisted yarn according to claim 1, characterized in that.

3. A woven or knitted fabric containing 20% or more by weight of the heat-fused false-twisted yarn according to claim 1 or 2.

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