Swimsuit

Abstract

Provided is a swimsuit that has excellent water repellency / low water retention rate / buoyancy and contributes to enhanced athletic ability. The present invention comprises a woven fabric in which a covering-covered yarn having a polyurethane elastic yarn as a core yarn and a synthetic fiber filament as a sheath yarn is disposed in at least a portion of warp and weft yarns, the polyurethane elastic yarn containing 0.5 to 10 mass% of a cationic high-molecular-weight compound having a number average molecular weight of 2,000 or more and an inorganic chlorine degradation inhibitor, the mass ratio of the cationic high-molecular-weight compound and the inorganic chlorine degradation inhibitor being 0.3 to 3, and the polyurethane elastic yarn including silicone, the synthetic fiber filament being constituted from synthetic fibers including single fibers having a plurality of grooves continuous in the fiber length direction, the depth of the grooves being 1.0-10.0 μm, the width of an inlet being 0.5-10.0 μm, the width of the tip of a protruding part being 10.0 μm or less, the porosity due to the fiber cross-sectional shape of the grooves being 5-30%, and the woven fabric including a flat woven fabric having a porosity of 75% or less and a weft double woven fabric, including a portion in which the flat woven fabric and the weft double woven fabric are repeated at a position covering the buttocks, and being subjected to a water repellent treatment.

Description

Swimsuit

[0001] The present invention relates to swimwear.

[0002] In competitive swimming, where every second counts, in addition to improving the skills of the swimmers, important issues include improving the buoyancy of the swimsuits worn by the swimmers, reducing water resistance, and ensuring stretch, low water retention, and high water repellency to ensure ease of movement in the water.To address these issues, efforts are underway to improve swimsuit fabrics.

[0003] For example, in order to improve buoyancy, it has been proposed to use a raw yarn with a C-shaped hollow cross section to obtain buoyancy due to the hollow portion (see, for example, Patent Document 1). According to this, it is said that excellent buoyancy can be obtained due to the high hollow ratio of the C-shaped hollow cross section.

[0004] Furthermore, a method has been proposed for reducing water resistance by using a weave structure with many floating yarns in the length direction of a swimsuit fabric (see, for example, Patent Document 2). It is described that water resistance can be effectively reduced by using raw yarns with a special cross-sectional shape having narrowed entrance grooves as floating yarns.

[0005] From the viewpoint of reducing water resistance, swimwear including a fabric in which plain weave portions and double weave portions are alternately repeated has also been proposed (see, for example, Patent Document 3).

[0006] Japanese Patent Application Publication No. 6-228820 International Publication No. 2021 / 100810 International Publication No. 2015 / 151820

[0007] As mentioned above, water-repellent fabrics intended for underwater wear must meet various requirements, including stretchability, water repellency, low water retention, buoyancy, and water resistance. Buoyancy and water resistance are particularly important factors for competitive swimsuits, which aim to improve competitive performance. One solution to water resistance is to increase the number of floating threads, but this increases the voids. While this provides excellent initial buoyancy, the voids retain water over time in water and with rubbing, which in turn reduces buoyancy. Additionally, materials with large voids generate turbulence, which increases surface water resistance. In other words, achieving both durable buoyancy and water resistance has been difficult until now.

[0008] For example, in the technology of Patent Document 1, although the initial buoyancy is excellent, the water-repellent performance of the hollow portion deteriorates with repeated wearing, and if water gets into the hollow interior, it acts to increase the weight of the swimsuit in water, thereby reducing the durability of the buoyancy. In addition, the water-repellent effect of the raw yarn structure cannot be expected, and the water-repellent property is insufficient.

[0009] Furthermore, although the technology of Patent Document 2 is excellent at reducing water resistance, increasing the number of floating threads increases the inter-woven voids in the fabric structure, which provides excellent buoyancy in the short term. However, over time and as the fabric is kneaded by exercise, water is retained in the inter-woven voids, increasing the weight in water and reducing buoyancy.

[0010] Similarly, the technology of Patent Document 3 is effective in reducing water resistance, but does not take buoyancy into consideration at all.

[0011] In view of the above, an object of the present invention is to reduce water resistance while improving buoyancy and its durability.

[0012] In order to solve the above problems, the present invention has the following configuration. (1) A swimsuit partially including a woven fabric in which covering yarns having polyurethane elastic yarns as core yarns and synthetic fiber filaments as sheath yarns are arranged as at least some of the warp and weft yarns, wherein the polyurethane elastic yarns contain 0.5 to 10 mass% of a cationic high-molecular-weight compound A having a number average molecular weight of 2000 or more, and also contain an inorganic chlorine-degradation inhibitor B, the mass ratio (A / B) of the cationic high-molecular-weight compound A to the inorganic chlorine-degradation inhibitor B being in the range of 0.3 to 3, and also contain silicone; the synthetic fiber filaments are composed of synthetic fibers including monofilaments at least some of which have a plurality of grooves on their surfaces that are continuous in the fiber length direction, the grooves having a depth of 1.0 to 10.0 μm, an opening width of 0.5 to 10.0 μm, and a tip width of the protrusions of 10.0 μm or less, and the void ratio due to the cross-sectional shape of the fiber of the grooves being 5 to 30%; the woven fabric includes a plain weave fabric and a weft double weave fabric, and the internal void ratio is 75% or less; (2) The swimsuit includes an area where the plain weave fabric and the weft double woven fabric are alternately repeated in a position covering at least the buttocks, and is treated with a water-repellent finish. (2) The swimsuit described in (1), wherein the area where the plain weave fabric and the weft double woven fabric are alternately repeated is located in at least a portion of the area covering from the navel to above the knees. (3) The swimsuit described in (1) or (2), wherein the area where the plain weave fabric and the weft double woven fabric are alternately repeated is located throughout the swimsuit. (4) The swimsuit described in any of (1) to (3), wherein the woven fabric is used in the main fabric of the swimsuit. (5) The swimsuit described in any of (1) to (4), wherein the woven fabric is used in the lining of the swimsuit. (6) The swimsuit described in any of (1) to (5), wherein the swimsuit covers only the upper body, and wherein the woven fabric accounts for 35% or more by mass of the swimsuit. (7) The swimsuit according to any one of (1) to (6), wherein the swimsuit covers only the upper body, and the mass ratio of the woven fabric in the swimsuit is, in the front body region and the back body region, front body region: back body region = 4 to 50: 50 to 96. (8) The swimsuit according to any one of (1) to (5), wherein the swimsuit covers both the upper and lower body, and the mass ratio of the woven fabric in the swimsuit is 28% or more.(9) The swimsuit according to any one of (1) to (5) and (8), wherein the swimsuit covers the upper and lower body, and the mass ratio of the woven fabric in the swimsuit is, in the front body region and the back body region, 7 to 45:55 to 93. (10) The swimsuit according to any one of (1) to (5), (8) and (9), wherein the swimsuit covers the upper and lower body, and the mass ratio of the woven fabric in the swimsuit is, in the upper body region that covers from the head to the center of gravity and the lower body region that covers from the center of gravity to above the knees, 2 to 45:55 to 98. (11) The swimsuit according to any one of (1) to (10), wherein the polyurethane elastic yarn has a fluorine / carbon (F / C) ratio of 0.030 or more in elemental mass concentration by scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX). (12) The swimsuit according to any one of (1) to (11), wherein the synthetic fiber filaments have 2 to 32 grooves. (13) The swimsuit according to any one of (1) to (12), wherein the synthetic fiber filaments are non-crimped multifilaments. (14) The swimsuit according to any one of (1) to (13), wherein the woven fabric is grade 4 or higher in the spray test described in JIS L 1092:2009. (15) The swimsuit according to any one of (1) to (14), wherein the woven fabric has a water retention rate after 60 minutes of 50% by mass or less of the fabric weight. (16) The swimsuit according to any one of (1) to (15), wherein the buoyancy per 1 g of the woven fabric is 0.0170 N or more. (17) The swimsuit according to any one of (1) to (16), wherein the cross-sectional shape of the synthetic fibers used in the woven fabric satisfies the following (Equation 1) and (Equation 2): W2 / W1≧1.3 (Equation 1) 0.15≦H / D≦0.25 (Equation 2) W1: width of groove entrance (μm) W2: width of wide groove portion (μm) H: groove depth (μm) F: fiber diameter (μm).

[0013] According to the present invention, a swimsuit can be provided that has excellent durable buoyancy and reduces surface water resistance.

[0014] The present invention has been briefly described above. The details of the present invention will become clearer by reading the following detailed description of the invention (hereinafter referred to as "embodiments") with reference to the accompanying drawings.

[0015] FIG. 1 is a schematic diagram illustrating the cross-sectional shape of an example of a single fiber used in the present invention. FIG. 2 is an enlarged schematic diagram illustrating a groove portion of an example of a single fiber used in the present invention. FIG. 3 is an enlarged schematic diagram illustrating a protrusion portion of an example of a single fiber used in the present invention. FIG. 4 is a schematic explanatory diagram illustrating a buoyancy measurement method. FIG. 5 is a partial enlarged view of an embodiment of the arrangement of distribution holes in a final distribution plate. FIG. 1 shows a swimsuit (men's competitive swimming swimsuit) according to a first embodiment, in which (A) is a front view, (B) is a side view, and (C) is a back view. FIG. 2 shows a swimsuit (men's competitive swimming swimsuit) according to a second embodiment, in which (A) is a front view, (B) is a side view, and (C) is a back view. FIG. 3 shows a swimsuit (men's competitive swimming swimsuit) according to a third embodiment, in which (A) is a front view, (B) is a side view, and (C) is a back view. FIG. 4 shows a swimsuit (women's competitive swimming swimsuit) according to a fourth embodiment, in which (A) is a front view, (B) is a side view, and (C) is a back view. FIG. 5 shows a swimsuit (women's competitive swimming swimsuit) according to a fifth embodiment, in which (A) is a front view, (B) is a side view, and (C) is a back view. 10A, 10B, and 10C are diagrams showing a swimsuit (women's competitive swimming swimsuit) according to a sixth embodiment, in which (A) is a front view, (B) is a side view, and (C) is a back view.

[0016] The present invention will be described in detail below. The term "to" in a numerical range includes the preceding and following numerical values. For example, "1.0 to 10.0" means a range of 1.0 or more and 10.0 or less. The covered coated yarn of the present invention uses a synthetic multifilament fiber as the sheath yarn. The synthetic multifilament yarn includes, as constituent filaments, synthetic fibers including filaments having, on their surfaces, a plurality of grooves that are continuous in the fiber length direction, at least a portion of which is a filament. As illustrated in FIG. 1 , which is a schematic diagram illustrating the cross-sectional shape of an example of a filament used in the present invention, the filament has a cross-sectional shape in which a plurality of grooves 12 with wide portions on the periphery are present, sandwiching protrusions 11 between them (hereinafter, this cross-sectional shape may also be referred to as a "special cross-sectional shape," and fibers having a special cross-sectional shape may also be referred to as a "special cross-sectional fiber").

[0017] The depth (H) of the grooves in the special cross-sectional shape is 1.0 μm to 10.0 μm. Water droplets adhering to the fiber surface enter the grooves due to their own weight and the kneading effect, and when they reach the bottom of the grooves, they adhere and become wet, resulting in a deterioration in water retention and buoyancy. However, if the grooves are deep, the surface tension of the water droplets pushes them upward, preventing them from becoming wet and maintaining water repellency. On the other hand, in multifilaments with a single fiber fineness of 2.5 to 5 dtex commonly used in swimsuits, the single fiber filament diameter is 12 to 26 μm, so if the grooves are designed to be excessively deep, there is a concern that the strength of the raw yarn will decrease. Therefore, the depth of the grooves is 10 μm or less, and preferably 8 μm or less.

[0018] When the diameter of the single fiber filament is small, it is preferable to control the groove depth within the above range so that the raw yarn strength is not excessively reduced, preferably by controlling the relationship between the diameter and the groove depth within the range described below. Furthermore, if the groove depth is too small, the droplets will reach the bottom of the groove, making it impossible to obtain sufficient water repellency. Therefore, in order to utilize the surface tension of the water droplets to exhibit water repellency, the groove depth is preferably 1 μm or more, as described above, and more preferably 2 μm or more.

[0019] The depth (H) of the groove in the special cross-section fiber is defined as the distance from a line 21 connecting the ends of the protrusions 11 present on either side of the groove (the distance of this line 21 is defined as the width (W1) of the groove entrance) to a center point 13 (not shown in FIG. 2) of the cross section perpendicular to the longitudinal direction of the synthetic fiber filament (the center point of the circumscribing circle that most frequently circumscribes the tips of the protrusions), and from the intersection of the line 21 connecting the ends of the protrusions and the perpendicular line 22 on the perpendicular line 22 to a tangent point 23 of the perpendicular line 22 and the fiber polymer portion. Also, as shown in FIG. 1, the center point 13 of the fiber is defined as the center point of the circle (hereinafter referred to as the circumscribing circle) that most frequently circumscribes the tips of the protrusions in the fiber polymer cross section, and the diameter of the circumscribing circle is defined as the fiber diameter (D) 14.

[0020] The width (W1) of the groove entrance in the special cross-sectional shape is 0.5 μm to 10.0 μm. When the groove entrance width is within the above preferred range, high water-repellent performance can be achieved by obtaining surface tension due to the surface tension of water droplets. If the groove entrance width is too small, the water-repellent agent will not penetrate into the groove, making it difficult to obtain water repellency. Therefore, the width is preferably 0.5 μm or more, and more preferably 1.0 μm or more. Furthermore, if the groove entrance width is too large, water will penetrate into the groove, resulting in a deterioration in water retention and buoyancy. Therefore, the width is preferably 10 μm or less, and more preferably 8 μm or less.

[0021] In the above-described special cross-sectional shape, preferred ranges for the groove inlet width (W1), the groove wide portion width (W2) 24, and the groove depth (H) relative to the fiber diameter (D) 14 are described below. The groove wide portion width (W2) 24 is the maximum width measured along the center line of the groove from the outer periphery toward the fiber center. A ratio W2 / W1 of the groove wide portion width (W2) to the groove inlet width (W1) of 1.3 or greater is preferred in that it allows more air to be trapped inside, improving buoyancy and water repellency. W2 / W1 is more preferably 1.5 or greater, and even more preferably 1.8 or greater. Furthermore, W2 / W1 is 3.0 or less, which suppresses cracking of the protrusions due to friction during wear and effectively maintains the shape of the groove inlet. Maintaining the shape of the groove inlet allows for maintenance of functionality.

[0022] Furthermore, it is preferable that the ratio (H / D) of the fiber diameter (D) to the groove depth (H) is 0.15 or more and 0.25 or less. This allows a sufficient air layer to be formed inside, thereby enabling functions such as water repellency and high buoyancy to be exhibited, while preventing performance degradation due to deformation or destruction of the protrusions forming the grooves when subjected to external force. H / D is more preferably 0.17 or more and less than 0.22. In summary, it is preferable that the special cross-sectional shape satisfies the following formula:

[0023] W2 / W1≧1.3 0.15≦H / D≦0.25 W1: width of groove entrance (μm) W2: width of wide groove part (μm) H: groove depth (μm) F: fiber diameter (μm)

[0024] The monofilament filament having grooves on its surface used in the present invention is preferably a monofilament filament in which the width 31 (Pout) of the tip of the protrusion, the width (W1) of the groove inlet, and the width (Pmin) 32 of the bottom of the adjacent groove satisfy the following formula: The width (Pout) 31 of the tip of the protrusion is the shortest distance connecting one tip of the protrusion to the other tip of the protrusion, and is the distance indicated by reference numeral 31 in Figure 3. The width (Pout) 31 of the tip of the protrusion is preferably 10.0 µm or less. If the width (Pout) of the tip of the protrusion exceeds 10.0 µm, water droplets may come into contact only with the tip of the protrusion without coming into contact with the air layer formed in the groove, and therefore the water repellency improvement effect cannot be sufficiently obtained. The width 32 (Pmin) of the bottom surface of the protrusion is, in other words, the distance connecting the tangent points of the inscribed circles of adjacent grooves across the protrusion, and is the distance indicated by reference numeral 32 in FIG.

[0025] Pout / W1=2~10 Pout / Pmin≧1.3

[0026] When the grooves in the special cross-section fiber are observed in a cross section perpendicular to the longitudinal direction of the fiber, the shape of the grooves is preferably teardrop-shaped, hexagonal, or other such shapes, with a wide portion wider than the entrance in the range from the entrance to the bottom of the groove, and the width of the groove gradually narrowing from the wide portion toward the bottom of the groove.

[0027] It is preferable that the special cross-section fiber have multiple grooves; if there is only one groove, depending on the orientation of the fiber, the groove may not be present at the interface with water, making it impossible to achieve improved water repellency. The number of grooves is preferably 2 to 32, more preferably 4 to 16. When the number of grooves is within the above preferred range, the width of the protrusions in the cross-sectional shape of the fiber does not become too small, and fibrils and fluff do not occur on the surface of the product during processing or use.

[0028] In the present invention, to obtain the above-mentioned special cross-sectional shape, it is desirable to use core-sheath composite fibers as the raw fiber. Here, core-sheath composite fibers are composed of two types of polymers, with the cross-section of the core component having the above-mentioned shape. The special cross-sectional fiber can be obtained by eluting the sheath component with a solvent or the like. Examples of the core component that can be used include polyamides such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, and nylon 6. From the perspective of simplifying the elution process, copolymerized polyesters, polylactic acid, polyvinyl alcohol, and the like that are easily soluble in aqueous solvents or hot water are preferred for the sheath component. In particular, polyesters and polylactic acid copolymerized with polyethylene glycol and sodium sulfoisophthalate, either alone or in combination, are preferred from the perspective of ease of handling and easy solubility in aqueous solvents. Furthermore, the mass ratio of the core component to the sheath component is preferably in the range of 50:50 to 90:10. The greater the ratio of the core component, which is the eluted component, the larger the air layer that can be formed in the cross section of the raw yarn, which is preferable for improving buoyancy. However, this can cause a deterioration in raw yarn strength and a prolonged elution process, so the above range is preferable, and a range of 60:40 to 80:20 is even more preferable.

[0029] The synthetic multifilament yarn used in the present invention is at least partially made of the above-mentioned special cross-section fiber, and the synthetic multifilament yarn may be entirely made of the above-mentioned special cross-section fiber, or may be made of other multifilaments. The other multifilaments may be multifilaments having a fiber cross-section other than the above-mentioned special cross-section fiber. Materials constituting such multifilaments include polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, and polyamides such as nylon 6. In this case, too, non-crimped multifilaments are preferred in terms of reducing the void ratio of the woven fabric.

[0030] In order to impart stretchability to woven fabrics, synthetic multifilaments are typically crimped by yarn processing, typically false twisting, to improve their elongation properties. However, when synthetic filaments are crimped, the crimping increases the inter-woven voids. In the present invention, it is important to minimize the inter-woven voids (reducing large voids) to prevent deterioration of water retention and buoyancy due to aging in water or crumpling during wear. Therefore, it is preferable to use a synthetic multifilament that has no substantial crimp, i.e., a non-crimped multifilament (hereinafter sometimes referred to as a non-crimped fiber). This allows for even smaller inter-woven voids. Here, "non-crimped" refers to a fiber that has not been subjected to crimping processing, such as false twisting, or to active crimping, as in the case of apparent crimped composite fibers (weaving crimp that inevitably occurs during weaving is not considered crimp).

[0031] As a means for reducing the interwoven voids other than using non-crimped fibers, there is a method of interweaving elastic fibers to produce a high density fabric.

[0032] The covering coated yarn of the present invention uses a polyurethane elastic yarn as the core yarn. The polyurethane elastic yarn contains 0.5 to 10 mass% of a cationic high-molecular-weight compound A having a number-average molecular weight of 2000 or more, and also contains an inorganic chlorine degradation inhibitor B, with the mass ratio of A / B satisfying the range of 0.3 to 3. This produces a significant synergistic effect, resulting in excellent chlorine degradation resistance and water-repellent finish. Further details about polyurethane elastic yarn are disclosed, for example, in JP 2020-169400 A.

[0033] The cationic high molecular weight compound used in the present invention is not particularly limited as long as it has an amino group in its structure. However, from the viewpoint of chlorine degradation resistance and yellowing of polyurethane elastic yarns, compounds having only tertiary amino groups among primary to tertiary amino groups in the molecule are particularly preferred. If the number-average molecular weight of the cationic high molecular weight compound is less than 2000, it may fall off due to friction with guides or knitting needles during knitting of the polyurethane elastic yarn, or may be washed out during processing in a dyeing bath, thereby deteriorating water-repellent finishability. Therefore, the number-average molecular weight must be 2000 or more. In consideration of solubility in polyurethane spinning dope, the number-average molecular weight is preferably in the range of 2000 to 10,000, more preferably 2000 to 4,000. The number-average molecular weight of the cationic high molecular weight compound can be measured by gel permeation chromatography (GPC) in polystyrene equivalent.

[0034] The inclusion of the cationic high molecular weight compound described above can enhance the water repellency of polyurethane elastic yarn. To ensure this effect is sufficient and not adversely affect the physical properties of the fiber, the cationic high molecular weight compound is preferably contained in an amount of 0.5% by mass or more and 10% by mass or less, and more preferably 0.5% by mass or more and 4% by mass or less, relative to the fiber mass.

[0035] The polyurethane elastic yarn of the present invention contains silicone. Preferably, the silicone is added to the polyurethane elastic yarn in the form of an oil, for example, within a specific range of 0.5% by mass to 20% by mass. This silicone is originally intended to minimize tension fluctuations during unwinding of the polyurethane elastic yarn during fabric production, thereby preventing thread breakage due to unwinding tension fluctuations even in fine elastic fibers. However, in the present invention, it significantly contributes to improving water-repellent properties. Furthermore, the silicone content in the treatment agent is preferably 0.5 to 10% by mass, and more preferably 1 to 6% by mass, on a dry mass basis. This improves affinity with the water-repellent treatment agent. For example, when silicone is contained in the oil agent, the surface energy of the fabric surface is reduced, significantly improving the diffusion performance of the water-repellent treatment agent when it is spread on the fabric surface. While any water-repellent treatment agent may be used in the present invention, it is preferable to use a treatment agent with an F / C ratio of 0.030 or higher in element mass concentrations measured by SEM-EDX on the polyurethane elastic yarn. In the element mass concentration of SEM-EDX on the polyurethane elastic fiber, an F / C ratio of 0.030 or more indicates that the amount of fluorine-based water repellent agent attached is large, and if the F / C ratio is less than 0.030, the amount of fluorine-based water repellent agent attached is small, and sufficient low wettability tends to be difficult to obtain. An F / C ratio of 0.045 or more is more preferable.

[0036] The covered coated yarn in the present invention has the above polyurethane elastic fiber as the core yarn and the synthetic fiber filament as the sheath yarn, but the covering method is not particularly limited as long as the above polyurethane elastic fiber is covered with the synthetic fiber filament by a method such as single covering or double covering. The draft ratio of the above polyurethane elastic fiber used as the core yarn is preferably 1.5 to 5 times, and preferably 2 to 4 times from the viewpoints of productivity and the stretchability of the resulting woven fabric.

[0037] The woven fabric of the present invention has the above-mentioned covering coated yarns arranged on at least a portion of the warp and weft. They may be used on either the warp or weft, or on both. They may also be used on a portion of the warp or weft. To maximize the effects of the present invention, it is preferable to use them on all the warp and weft. The weave may be plain weave, twill weave, or multilayered, but it is preferable to include at least a plain weave and a weft-double weft weave in terms of reducing water resistance and buoyancy.

[0038] Furthermore, a fabric woven at a high density is preferred to achieve low water retention, and a total cover factor (Cf) of 2300 or more is preferable. If the total cover factor is small, the number of crossing points will be reduced, and the constraint on the weaving yarns will be reduced, resulting in problems such as twisting and snagging. Furthermore, the weave structure will become looser, increasing the gaps between the structures, which may lead to a decrease in water retention when worn. For this reason, a total cover factor of 2500 or more is more preferable, and 2700 or more is even more preferable. If Cf is too high, it is likely to lead to a deterioration in tear strength and productivity, so a total cover factor of 3500 or less is preferable, and from the viewpoint of obtaining a fabric with excellent tear strength, a total cover factor of 3000 or less is more preferable.

[0039] Furthermore, to prevent a decrease in water retention, the porosity of the woven fabric is 75% or less, preferably 70% or less. The porosity here refers to the porosity per volume, and refers to the parameter expressed by the following formula:

[0040] Vall = {(V - v) / (V)} x 100 Vall: void ratio (%) of fabric V: apparent volume of fabric (volume measured) v: true volume of fabric (volume of synthetic fiber calculated from the density of the components that make up the synthetic fiber)

[0041] Furthermore, the void ratio calculated using the above parameters includes voids between the woven yarns of the synthetic multifilament yarns that make up the weave, voids between the single fibers that make up the synthetic multifilament yarn, and voids due to hollows such as grooves in special cross-section fibers. When special cross-section fibers with hollows are used, many fine air layers are formed compared to fibers with round cross-sections. The formation of such fine air layers makes it possible to achieve a high level of the contradictory properties of low water retention and high buoyancy, so it is desirable for many fine air layers to be present in the weave.

[0042] Therefore, in the present invention, the degree of voids formed by the grooves of the special cross-section fibers contained in the woven fabric is such that the void ratio due to the fiber cross-sectional shape of the single fiber having multiple grooves on its surface is in the range of 5 to 30%, with 10 to 30% being preferred. The void ratio due to the fiber cross-sectional shape of the single fiber having multiple grooves on its surface referred to here is a value calculated by the following method.

[0043] That is, the area of ​​the voids is calculated by subtracting the area of ​​the actual cross section of the special cross section fiber (actual area) from the area of ​​the circumscribed circle that most closely contacts the periphery of the cross section of the special cross section fiber in the direction perpendicular to the fiber length direction, and the void ratio is the ratio to the area of ​​the circumscribed circle. Note that when the fiber cross section is a round and solid fiber (hereinafter referred to as a solid round cross section fiber), the periphery theoretically coincides with the circumscribed circle, and the void ratio is 0%. On the other hand, in the case of a special cross section, the area of ​​the circumscribed circle is larger than the area of ​​the special cross section fiber itself. In the present invention, the difference area is divided by the area of ​​the circumscribed circle, and the result expressed as a percentage is the "void ratio due to the fiber cross section shape of a single fiber having multiple grooves on its surface" (hereinafter referred to as the "void ratio due to the cross section shape of the special cross section fiber") per single fiber of the special cross section fiber.

[0044] Vcs = {(Ac - a) / Ac} x 100% Vcs: void ratio (%) due to the cross-sectional shape of the special cross-section fiber per single fiber Ac: area of ​​the circumscribed circle that most closely contacts the cross-section of the special cross-section fiber a: actual area of ​​the cross-section of the special cross-section fiber

[0045] In addition, when sheath-core composite fibers are used as the raw fiber for the special cross-section fiber, and the cross-sectional shape of the sheath-core composite fiber before the elution of the sheath component is a solid round cross-section, the special cross-sectional shape is developed by the elution of the sheath component, and there is no significant difference in density between the eluted and non-eluted components (for example, when the ratio of the absolute value of the difference in density between the eluted and non-eluted components to the density of the higher density is 10% or less), the elution rate during the elution treatment of the sheath component from the core-sheath composite fiber may be used as a substitute for the porosity per single fiber in the special cross-section fiber due to the cross-sectional shape of the special cross-section fiber (hereinafter referred to as the "substitution method"). To determine this elution rate, a fabric (which may be woven or knitted) consisting of 100% core-sheath composite fiber is used, and the absolute value of the difference in mass before and after the elution treatment is calculated as a percentage relative to the mass of the fabric before the elution treatment. However, if the determination of whether the porosity satisfies the above range varies depending on whether or not this substitution method is used, the formula for determining Vcs described above should be used.

[0046] Furthermore, when special cross-section fibers are mixed with other fibers, the porosity due to the cross-sectional shape of the special cross-section fiber per single fiber can be defined as the porosity due to the cross-sectional shape of the special cross-section fiber in the woven fabric by multiplying the porosity due to the cross-sectional shape of the special cross-section fiber per single fiber by the blend ratio of the solid cross-section fiber (equivalent to the blend ratio of the core-sheath composite fiber in cases where the above-mentioned substitution method can be used). That is, when a single fiber contains 80% by mass of special cross-section fibers with a porosity due to the cross-sectional shape of the special cross-section fiber of 20% and 20% by mass of other fibers, the mass ratio of the solid cross-section fiber with a cross-section equal to the circumscribed circle to the other fibers is 100:20, so the assumed blend ratio of solid cross-section fibers is calculated as 100 / 120 = 0.83 (83% by mass). Therefore, the porosity due to the cross-sectional shape of the special cross-section fiber in the woven fabric can be calculated as 20% × (100 / 120) = 16.7%.

[0047] When determining the void ratio from a woven fabric that uses other fibers, the special cross-section fibers are extracted from the woven fabric, the void ratio per single fiber resulting from the cross-sectional shape of the special cross-section fiber is determined, and the void ratio can be determined by multiplying this by the assumed blend ratio of solid cross-section fibers. When a woven fabric is composed only of special cross-section fibers, the void ratio resulting from the cross-sectional shape of the special cross-section fiber per single special cross-section fiber is multiplied by the assumed blend ratio of solid cross-section fibers of 100% by mass to determine the void ratio resulting from the cross-sectional shape of the special cross-section fiber.

[0048] As described above, the special cross-section fiber used in the present invention preferably uses core-sheath composite fibers as raw materials, and the special cross-section fiber can exhibit a special cross-sectional shape by eluting the sheath component of the core-sheath composite fiber. The elution, dyeing, and finishing processes required for this purpose involve scouring, relaxing, and drying the gray fabric, followed by heat-setting the width in an intermediate setting to elute the sheath component. The fabric is then dyed, and reduction-washed if made of polyester, or fixed if made of nylon, followed by washing in hot water and drying. Next, a water-repellent treatment and, if necessary, various functional treatments are applied, followed by a finishing and setting process.

[0049] It is essential that the swimsuit of the present invention be subjected to a water-repellent treatment. The water-repellent treatment may be performed at any stage, such as at the yarn, fabric, or swimsuit stage. The water-repellent agent used in the water-repellent treatment may be any of fluorine-based, silicone-based, and paraffin-based agents, but fluorine-based water-repellents are preferred in terms of water-repellent performance. In particular, fluorine-based water-repellents with 8 or more carbon atoms (so-called C8 water-repellents) are preferred in terms of performance, but PFOA-free fluorine-based water-repellents with 6 carbon atoms (C6 water-repellents) that do not produce perfluorooctanoic acid (PFOA) are preferred from the perspective of environmental impact. Furthermore, in view of the market environment demanding fluorine-free products, the use of non-fluorine-based water-repellents (C0 water-repellents) such as paraffin-based, acrylic-based, and silicone-based agents, either alone or in combination, is more preferred.

[0050] In order to improve the durability of the water repellency, it is preferable to use a crosslinking agent in combination with the water repellent agent. As the crosslinking agent, at least one of melamine-based resins, blocked isocyanate-based compounds, glyoxal-based resins, and imine-based resins can be used, and the crosslinking agent is not particularly limited.

[0051] To impart water repellency to the surface, interior and back surfaces of the fabric, it is preferable to perform the water repellency treatment by a method such as Pad-Dry-Cure.

[0052] Furthermore, the water-repellent treatment on the surface, interior, and back of a woven fabric can be confirmed by observing a cross section of the woven fabric in the thickness direction with a scanning electron microscope (SEM) to confirm the presence or absence of a water-repellent coating on the surface of each fiber present on the surface, interior, and back of the woven fabric. The presence or absence of a water-repellent coating does not necessarily require a continuous coating to be formed inside the grooves or on the outer periphery of the fibers; even if there are partial resin defects in the observed field of view, it is determined that a coating is present if it is confirmed that the coating is attached over the entire outer periphery of the fibers.

[0053] In the woven fabric of the present invention, the water repellency (grade) is preferably Grade 4 or higher according to the JIS L1092:2009 spray method, and it is also desirable to maintain Grade 3 or higher even after 20 washes according to the JIS L0217:1995 103 method. Generally, the water repellency of water-repellent materials decreases with washing, and in particular, when a non-fluorinated water repellent agent is used as the water repellent agent, the washing durability of the water repellency is inferior to that of a fluorinated water repellent agent. However, in the present invention, the use of special cross-section fibers can compensate for the decrease in water repellency, allowing excellent water repellency to be maintained even after washing.

[0054] Furthermore, if a woven fabric retains water, its buoyancy will decrease because water is heavier than air, resulting in a worsening wearing comfort in water. Therefore, the woven fabric of the present invention preferably has a water retention rate of 50% by mass or less of the woven material weight after 60 minutes, more preferably 40% by mass or less, and even more preferably 30% by mass or less. A water retention rate of 0% by mass is most preferable, but in practice, 3% by mass is assumed to be the lower limit. Although low initial water retention can be achieved even in materials with many coarse voids between the weaves depending on water repellency, maintaining low water retention requires a design that reduces coarse voids, as in the present invention. Therefore, the water retention rate is evaluated based on the water retention rate after 60 minutes of simulated actual use.

[0055] Furthermore, in competitive swimming where swimming speed is a crucial factor, it is preferable that the weight of the material when worn is even 0.1 g lighter in order to improve athletic performance, and the woven fabric preferably has a buoyancy of 0.0170 N or more per 1 g of fabric, more preferably 0.0185 N or more, and even more preferably 0.0200 N or more. Furthermore, since excessive buoyancy impairs ease of movement in water, it is preferable that the buoyancy be 0.0300 N or less.

[0056] Furthermore, the buoyancy per gram of fabric after 20 minutes is preferably 0.0165 N or more, more preferably 0.0180 N or more, and even more preferably 0.0195 N or more. For the same reasons as for the initial buoyancy, it is desirable that it be 0.0300 N or less. The reason that the buoyancy after 20 minutes is lower than the initial level is because the coarse voids between the tissues retain water over time, and with a material having many fine voids like the present invention, the decrease in buoyancy can be minimized.

[0057] The woven fabric of the present invention preferably has a tear strength of 8 N or more, more preferably 10 N or more, and even more preferably 12 N or more, as measured in accordance with JIS L1096:1999. One example of a method for obtaining a woven fabric having the above tear strength is to use a single yarn of 1.5 dtex or more and, as described above, set the total cover factor to 3000 or less.

[0058] Furthermore, the woven fabric preferably has a burst strength of 200 kPa or more, more preferably 300 kPa or more, and even more preferably 400 kPa or more, as measured in accordance with JIS L1096:1999. One example of a method for obtaining a woven fabric with the above burst strength is to use a thick yarn with a single yarn fineness and weave it to achieve a high total cover factor. Specifically, this can be achieved by using a yarn with a single yarn fineness of 1.5 dtex or more and achieving a total cover factor of 2500 or more.

[0059] By satisfying these strength requirements, sewn products can be prevented from tearing or ripping when worn, and high durability can be maintained.

[0060] The swimsuit of the present invention includes a portion of the above-mentioned woven fabric in which plain weave fabric and weft double weave fabric are alternately repeated at least in the portion covering the buttocks. The periodic riblets formed on the surface of the fabric suppress the generation of turbulence, thereby reducing water resistance. Furthermore, the swimsuit of the present invention improves buoyancy by using the above-mentioned woven fabric, and the riblet structure of the fabric traps air bubbles, forming air layers not only within the fabric and between the yarns but also on the surface of the fabric, thereby achieving a synergistic effect of further improving buoyancy.

[0061] The woven fabric of the present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The evaluations in the examples were determined by the following methods.

[0062] (1) Various cross-sectional parameters of special cross-section fibers A part of the woven fabric was cut perpendicular to the fiber axis so that the cross-sectional shape of the special cross-section fiber could be observed. The special cross-section fiber was extracted using a scanning electron microscope (SEM) manufactured by Hitachi High-Technologies Corporation, and the width of the groove entrance (W １ ), the width of the wide part of the groove (W ２ ), the depth (H) of the groove, and the fiber diameter (D) were measured. Furthermore, for the protrusions of the special cross-section fiber, the width of the tip of the protrusion (P ｏｕｔ ) and the width of the bottom surface of the protrusion (P ｍｉｎThe same measurement was performed on five special cross-section fibers, and the average value was taken as the respective values. These values ​​were calculated to two decimal places in μm units and rounded off to the nearest tenth.

[0063] (2) Cover factor (2-1) Apparent fineness of decomposed yarn of woven fabric Warp and weft yarns were extracted from the woven fabric, and their apparent density was measured in accordance with "Method for measuring apparent fineness of fibers extracted from fabric" in Appendix H of JIS L1096:2010. In the case of processed products with resin coating or film laminate, the apparent fineness was measured by the method described in "Chapter 3: Measurement of apparent fineness of fibers extracted from fabric after removing non-fibrous substances" in which non-fibrous substances were removed by the method described in ISO1833-1, and in the case of dyed and finished products without resin treatment (including water-repellent and softening treatments), the apparent fineness was measured by the method described in "Chapter 2: Measurement of apparent fineness of fibers extracted from fabric without removing non-fibrous substances".

[0064] The mass of the yarn was measured under standard conditions (20°C, 65% RH) after adjusting it to moisture equilibrium (Method A) and calculated using the following formula: The number of measurements was 40 or more.

[0065] Ld = Ws / L x n Ld: apparent fineness (tex) of yarn adjusted under standard conditions Ws: mass (g) of yarn taken out of fabric L: average length (m) when pulled straight n: number of yarns weighed

[0066] When pulling the thread straight, the following initial load was applied and measured.

[0067] Non-crimped synthetic fiber filament: Initial load (cN) = Fineness (tex) × 0.5

[0068] In the case of covered yarns, the apparent fineness was measured in a covered state without separating the yarn drawn out from the fabric into the elastic fiber core yarn and the synthetic fiber filament sheath yarn.

[0069] (2-2) Density The density of the woven fabric was measured by measuring the number of threads per 1 cm according to Method B (Fabric Disassembly Spectrometer) of Appendix F of JIS L1096:2010, and converted to the number per inch (2.54 cm). The number of measurements was the average of three times for both the warp and weft.

[0070] (2-3) Cover Factor The cover factor was calculated by substituting the above-mentioned measurement results of apparent fineness and density into the following formula: Cf = Cfw + Cff Cfw = Nw × √Dw Cff = Nf × √Df Cf: Total cover factor Cfw: Cover factor in warp direction Cff: Cover factor in weft direction Nw: Weave density in warp direction Nf: Weft density Dw: Warp fineness (dtex) Df: Weft fineness (dtex)

[0071] (3) Basis Weight The basis weight was measured in accordance with JIS L1096:2010, 8.3.2., Method A, under standard conditions (20°C, 65% RH). That is, three 200mm x 200mm test pieces were taken, and the mass (g) of each was measured after leaving it for one day under standard conditions. The mass per unit area was calculated using the following formula: ２ Mass per unit (g / m ２ ) was calculated, the average value was calculated, and the average value was rounded to an integer.

[0072] Sm = W / A Sm: Mass per unit area under standard conditions = basis weight (g / m ２ ) W: Mass of the test piece under standard conditions (g) A: Area of ​​the test piece (m ２ )

[0073] (4) Thickness The thickness was measured in accordance with JIS L1096:2010, 8.4, using a thickness gauge at five different points on a humidity-conditioned sample according to Method A, and the thickness was measured when the sample was pressed at a pressure of 23.5 kPa for 10 seconds, and the average value was calculated.

[0074] (5-1) Porosity The apparent volume (V) of the test piece was calculated by multiplying the area of ​​the test piece prepared in (3) by the thickness calculated in (4). Furthermore, the true volume (v) of the fiber structure was calculated using the following formula from the mass (Wc) of the test piece and the density and blending ratio of the components constituting the synthetic fiber used. If the density and blending ratio are known, these values ​​may be used. However, if they are unknown or if evaluation is performed from a woven fabric, the density should be measured in accordance with JIS L 1013:2021 8.17.2 (density gradient tube method), and the blending ratio should be measured using the JIS L 1030-2:2021 dissolution method or dissolution method.

[0075] v = Wc x 100 / {(ra x da} + (rb x db) + ... + (rz x dz)} v: True volume Wc: Mass of test piece ra: Mixture ratio of component a da: Density of component a (g / cm ３ ) rb: Mixture ratio of b component db: Density of b component (g / cm ３ ) Same as above for components c and later.

[0076] Furthermore, the apparent volume and true volume determined by the above method were substituted into the following equation to determine the void volume Vall of the woven fabric.

[0077] Vall = {(V - v) / (V)} x 100 Vall: void ratio (%) of fabric V: apparent volume of fabric (volume measured) v: true volume of fabric (volume of synthetic fiber calculated from the density of the components that make up the synthetic fiber, as mentioned above)

[0078] (5-2) Porosity due to the fiber cross-sectional shape of a single fiber having a plurality of grooves on its surface In view of the densities of the components constituting the sheath-core composite fibers used in the Examples and Comparative Examples, it was clear that evaluation using an alternative method would not pose any problems. Therefore, in the Examples, evaluation was carried out using the alternative method.

[0079] Knitted fabrics using the core-sheath composite fibers having a round cross section before leaching produced in the Examples and Comparative Examples were produced using a 28G cylindrical knitting machine, and after humidity conditioning for 24 hours under standard conditions (20°C, 65% RH), the mass (Wb) before leaching was measured.

[0080] Furthermore, after elution treatment in a 10 g / L aqueous sodium hydroxide solution at 100°C for 60 minutes at a bath ratio of 1:30, the fiber was hung to dry for 24 hours under standard conditions (20°C, 65% RH). The mass (Wa) after elution of the sheath components was then measured, and the elution rate was calculated using the following formula. Comparison of the elution rate with the design value for the fiber confirmed that 100% of the sheath components had been eluted. This elution rate was taken as the porosity due to the cross-sectional shape of the special cross-section fiber per single fiber of the special cross-section fiber.

[0081] Elution rate (%) = (Wa-Wb) x 100 / Wb

[0082] Furthermore, the void ratio due to the cross-sectional shape of a single fiber having a plurality of grooves on its surface (void ratio due to the cross-sectional shape of a special cross-section fiber) was calculated by multiplying the blend ratio of core-sheath composite fibers in the fabric before leaching by the leaching rate.

[0083] (6) Water Repellency The water repellency was measured according to JIS L1092:2009, Section 7.2, Water Repellency Test (Spray Test). Three samples measuring approximately 200 mm x 200 mm were collected, and using a water repellency tester, 250 ml of water was placed in a funnel so that the longitudinal direction of the sample was parallel to the water flow. The water was sprayed onto the sample for 20 to 25 seconds. Next, the sample holder was removed from the device, and one end was held horizontally. With the front side of the test piece facing downwards, the other end was lightly touched against a hard object once to remove water droplets. The other end was then rotated 180° and the same procedure was repeated to remove any excess water droplets. The wet state of the sample was evaluated by comparing it with a control sample while still attached to the holder.

[0084] The water-repellent fabric was washed using the method 103 described in JIS L0217:1995 "Handling symbols and labeling methods for textile products." The fabric was washed 20 times, and the water-repellent properties after washing were evaluated by the spray test described above.

[0085] (7) Water Retention Rate A circle with a diameter of 11.2 cm was drawn in the center of a piece of fabric cut to 20 cm lengthwise and 20 cm widthwise, and the fabric was stretched so that the area of ​​the circle was enlarged by 80%. The fabric was then attached to a test piece holder frame used for the water repellency test (JIS L1092:2009). After a spray test (JIS L1092:2009), the fabric was removed from the holder frame and air-dried in an environment of 20°C x 53% RH. Ten pieces of the same fabric were prepared, and the mass of each piece was measured, which was recorded as the "mass before treatment."

[0086] A washing machine (JIS C9606:2007) was filled with 30 L of water (water temperature: 25 to 29°C), and 10 of the above-mentioned fabrics were placed in the water and rotated under "strong conditions" for a predetermined time (10 minutes, 60 minutes). Each fabric was then removed from the water one by one, tilted at an angle of about 15 degrees in an open-faced state, and left for 10 seconds, after which water droplets on the fabric were removed. The mass was measured and this was taken as the "mass after treatment," and the water retention was measured using the following formula.

[0087] Water retention rate (%) = ((mass after treatment - mass before treatment) / mass before treatment) x 100

[0088] (8) Buoyancy Test First, the load (WA1) of the sample in air was measured using a Shimadzu Corporation electronic balance, model AUY220. Next, the load (WA2) in water was measured using the buoyancy measurement method shown in Figure 4. Figure 4 is a schematic explanatory diagram showing the buoyancy measurement method. In a buoyancy test apparatus 40, water 42 was placed in a container 41, a test sample 48 was placed in the water, and a hanging balance (Shimadzu Corporation electronic balance, model AUY220) serving as a weigh scale 43 was fixed above the water. The test apparatus held the weigh scale 43 between a support 44 and a plate 46, and a support rod 45 and a wire mesh 47 were attached. As shown in Figure 4, the wire mesh 47 was placed in water, and the test sample 48 was suspended from the weigh scale 43 with the wire mesh 47 sandwiched between them. The load (WA2) in water (the value measured by the hanging balance) was measured. The buoyancy was calculated by subtracting WA1 from WA2. Five randomly taken samples of 3 cm length and 4 cm width were measured from the fabric, and the measurements were carried out on each sample to calculate the average value. For the fabric samples used in measuring WA1, the dry load was measured.

[0089] (9) Tear Strength Evaluation was carried out by the pendulum method specified in JIS L1096 "Testing methods for woven and knitted fabrics" (1999).

[0090] (10) Burst Strength: Evaluation was carried out by the Mullen method specified in JIS L1096 "Testing Methods for Woven and Knit Fabrics" (1999).

[0091] (11) Preparation of Fabric A Nylon 6 (N6) (density: 1.14 g / cm ３ ) as the core, and polyethylene terephthalate (copolymer PET1) copolymerized with 8.0 mol% of 5-sodium sulfoisophthalic acid and 10 wt% of polyethylene glycol having a molecular weight of 1,000 (density: 1.26 g / cm ３Using a spinneret designed to dispose the core and sheath in the sheath, the core and sheath were melted separately at 270°C and then flowed into the spinneret. The composite polymer stream was discharged from the discharge holes to obtain a core-sheath composite drawn fiber yarn (33 dtex / 10 filaments). The distribution plate immediately above the discharge plate had the arrangement pattern shown in Figure 5 at the interface between the core and sheath components, so that teardrop-shaped grooves with eight wide portions were formed on the surface of each single filament. By arranging the distribution holes 52 for the sheath component between the distribution holes 51 for the core component, the sheath component was positioned so that it was sandwiched between the core components discharged from the distribution holes for the core component, forming a core-sheath composite polymer stream with a specially controlled groove shape. The core-sheath composite ratio was adjusted to 80:20 by mass.

[0092] Next, to obtain polyurethane elastic yarn, PTMG having a number average molecular weight of 1800 and MDI were charged into a vessel in a molar ratio of MDI / PTMG = 1.58 / 1 and reacted at 90°C, and the resulting reaction product was dissolved in N,N-dimethylacetamide (DMAc). Next, a DMAc solution containing ethylenediamine and diethylamine was added to the solution in which the reactants had been dissolved, to prepare a polyurethane urea solution with a solid content of 35 mass% in the polymer. Furthermore, a condensation polymer of p-cresol and divinylbenzene ("Methachlor" (registered trademark) 2390 manufactured by DuPont) as an antioxidant and 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)phenol ("Cyasorb" (registered trademark) 1164 manufactured by Cytec Corporation) as an ultraviolet absorber were mixed in a mass ratio of 3:2 to prepare a DMAc solution (concentration: 35% by mass), which was used as an additive solution (35% by mass). The polyurethane urea solution and the additive solution were mixed in a ratio of 98% by mass and 2% by mass to prepare a polymer solution (X1). As a cationic high molecular weight compound, a cationic high molecular weight compound having a number average molecular weight of 2600 was produced by reacting t-butyldiethanolamine with methylene-bis-(4-cyclohexyl isocyanate). The number average molecular weight of the cationic high molecular weight compound was measured by gel permeation chromatography (GPC) under the following measurement conditions: (Measurement conditions) Standard material: polystyrene Column: two SHODEX KF-806M columns manufactured by Showa Denko K.K. Solvent: N,N-dimethylacetamide (DMAc) at 1 ml / min Temperature: 40°C Detector: differential refractometer (RI detector)

[0093] The resulting cationic high molecular weight compound was dissolved in DMAc to prepare a solution (A1) with a concentration of 35% by mass. ３A 35% by mass DMAc dispersion was prepared using a horizontal mill, DYNO-MILKDL, manufactured by Willya Bachofen GmbH. 85% zirconia beads were filled into the mill and finely dispersed uniformly at a flow rate of 80 g / min to prepare a DMAc dispersion B1 (35% by mass) of synthetic carbonate. Furthermore, ethylene-1,2-bis(3,3-bis[3-t-butyl-4-hydroxyphenyl]butyrate (Clariant Corporation) was used as a one-hindered phenol compound. "Hostanox" (registered trademark) O3) manufactured by POLYMER AGENT INC. (POLYMER AGENT INC.) was dissolved in DMAc to prepare a 35% by mass solution (C1). Polymer solutions X1, A1, B1, and C1 were mixed at ratios of 97%, 1%, 3%, and 1% by mass, respectively, to prepare spinning solution Y1. Furthermore, the mass ratio (A / B) of the cationic high molecular weight compound to the inorganic chlorine degradation inhibitor was 0.33 based on the amounts added. This spinning solution Y1 was dry-spun at a take-up speed of 580 m / min to produce polyurethane elastic yarns (44 dtex, 55 dtex, and 78 dtex) (Z1), which were then wound up while being coated with a silicone oil treatment agent. The silicone oil was a treatment agent (oil) consisting of 96% silicone (polydimethylsiloxane), 3% St-Mg, and 1% dispersant, with 6% added by dry weight.

[0094] The core-sheath composite fiber drawn yarn obtained as described above was used as a sheath yarn as a non-crimped yarn that had not been subjected to yarn processing such as false twisting, and a polyurethane elastic yarn was used as a core yarn to prepare a single covered yarn, and the following three types of yarn were obtained depending on the fineness of the polyurethane elastic yarn.

[0095] Yarn A: core-sheath composite fiber drawn yarn (33 dtex) × polyurethane elastic yarn (78 dtex) Yarn B: core-sheath composite fiber drawn yarn (33 dtex) × polyurethane elastic yarn (55 dtex) Yarn C: core-sheath composite fiber drawn yarn (33 dtex) × polyurethane elastic yarn (44 dtex)

[0096] A stretch fabric was woven using yarn A as the warp, yarn B as the weft, and yarn C as the weft back yarn, with alternating plain weave and weft double weave sections. The resulting fabric was a blend of 65% by mass nylon and 35% by mass polyurethane. The fabric was then relaxed scoured in an open-weave state according to conventional methods and pre-set. Next, the fabric was jet-dyed with a 1% by mass aqueous solution of sodium hydroxide at 100°C for 60 minutes in a bath ratio of 1:30 to dissolve 100% of the sheath component, converting the core-sheath composite fibers in the fabric into special cross-section fibers. After the dissolution treatment, the fabric was dyed black using an acid dye in a jet-dyeing machine according to conventional methods. Next, a soaping treatment using a surfactant aqueous solution and a fixation treatment were performed according to conventional methods.

[0097] The fabric was then immersed in a non-fluorine-containing water repellent treatment liquid of the following formulation, squeezed to a squeezing rate of 60% using a mangle, dried at 130°C for 2 minutes, and then subjected to a final set at 160°C which also served as curing.

[0098] [Formulation of water-repellent treatment liquid] "Neoseed (registered trademark)" NR-158 (manufactured by Nicca Chemical Co., Ltd.)...5.0 mass% "Amidea (registered trademark)" M-3 (manufactured by DIC Corporation)...0.3 mass% "Catalyst" ACX (manufactured by DIC Corporation)...0.3 mass% Isopropyl alcohol...1.0 mass% Water...93.4 mass%

[0099] The resulting woven fabric had a warp density of 198 threads / 2.54 cm and a weft density of 205 threads / 2.54 cm, and after elution, the blend ratio was 60% by mass of nylon 6 (Ny) and 40% by mass of PU. ２ , thickness 0.32 mm, and the density of the components constituting these and nylon fiber is 1.14 g / cm ３ , and the density of the PU fiber is 1.0 g / cm ３ The void ratio of the woven fabric was calculated to be 67.1%. Furthermore, the leaching treatment resulted in 20% more voids than the round cross-section sheath-core composite fibers before leaching, and since the blend ratio of sheath-core composite fibers before leaching was 65% by mass, the void ratio due to the cross-sectional shape of the special cross-section fibers was 13.0%.

[0100] In addition, scanning electron microscopy of the grooves on the cross section of the sheath-core composite fiber after the sheath component was dissolved revealed that there were eight grooves around the fiber circumference, with the groove entrance width being 0.6 μm and the wide portion of the groove being 1.1 μm (W2 / W1 = 1.8), resulting in a unique cross section with teardrop-shaped grooves with wide portions. The fiber diameter was 9.97 μm, and the groove depth was 1.9 μm (H / D = 0.19), resulting in the desired shape capable of adequately maintaining an air layer. The width of the tip of the protrusion was 4.9 μm, and no peeling or collapse of the protrusions occurred during the processing process. Furthermore, the fluorine / carbon (F / C) ratio on the polyurethane elastic fiber was measured using elemental mass concentration by SEM-EDX, resulting in F / C = 0.048.

[0101] Furthermore, the water repellency, water retention, and buoyancy of the resulting fabric were evaluated using a spray method, and the results are shown in Table 1. The water-repellent fabric obtained by this method had a water-repellent coating formed on the fiber surfaces of the surface, inside the fabric, and backside, and had low water retention and high buoyancy both initially and over time, making it suitable for wearing in water.

[0102] (12) Production of Fabric B A plain weave fabric was produced using single covered yarns for the warp and weft, with the same 33 dtex, 10 filament semi-dull, round cross section nylon 6 drawn yarn (solid fiber) as the sheath yarn as used for the warp of Fabric A, and was then subjected to scouring, relaxation, dyeing, and water repellent treatment using the same process as for Fabric A, except that the leaching treatment was removed.

[0103] The resulting woven fabric had a warp density of 197 threads / 2.54 cm, a weft density of 176 threads / 2.54 cm, and a blend ratio of Ny 73% by mass and PU 27% by mass. ２ The porosity of the woven fabric was calculated to be 67.3% using the same calculation method as for Fabric A. In addition, since all of the raw yarns used had a round cross section, the porosity due to the cross-sectional shape of the fibers was 0%.

[0104] Furthermore, the water repellency, water retention, and buoyancy of the resulting fabric were evaluated using a spray method, and the evaluation results are shown in Table 1. Because the water-repellent fabric obtained using this method had a water-repellent coating formed on the fiber surfaces on both the front, inside, and back of the fabric, it had excellent water retention, but low buoyancy, and was considered to be insufficient for the performance required for wearing underwater. Table 1 also shows the evaluation results of Fabric C, which was made by replacing only the warp yarns of Fabric A with a round cross-section. Although slightly inferior to Fabric A, Fabric C also had low water retention and high buoyancy both initially and over time, making it suitable for wearing underwater.

[0105]

[0106] (13) Application to swimwear (13-1) Relationship between center of buoyancy and center of gravity in swimming posture To swim fast, it is necessary to maintain a swimming posture that is horizontal to the water surface and reduces resistance. However, as swimmers become tired in the latter half of a race, their stomachs and lower legs sink, making them more susceptible to water resistance. Solutions to this include swimsuits that support the hamstrings to prevent the lower legs from sinking and swimsuits with foam inserts, but no competitive swimsuits have been developed to date that optimally position the buoyancy effect of fabric alone.

[0107] The inventors created a weft double weave fabric using FTY (raw yarn) made of synthetic fiber filaments with voids in the fiber cross section as the sheath yarn and polyurethane elastic yarn, to which water repellent agents are easily attached, as the core yarn, like Fabric A, and confirmed that the buoyancy effect was greater than that of fabrics without voids. Furthermore, the inventors confirmed that the surface friction resistance due to the weave structure was reduced compared to plain weave structures.

[0108] Based on the above results, the inventor developed a swimsuit in which this fabric is partially placed from the center of gravity to the lower legs. Normally, the center of buoyancy during swimming is closer to the head than the center of gravity, so a moment in the direction of gravity is applied to the lower legs. By placing fabric with a high buoyancy effect from the center of gravity to the lower legs, swimmers can more easily assume a horizontal position relative to the water surface, get the feeling that their lower legs are floating, and maintain a posture with less resistance.

[0109] (13-2) Swimsuit Construction Fabric A is used in a striped pattern along the body's height. This reduces surface friction resistance with the water flow. To further reduce surface friction resistance, it is desirable to use it in the waist to buttocks area, where the body's contours are more irregular, thereby achieving a greater effect in suppressing turbulence. Furthermore, it is desirable to use Fabric A in part or all of the leg area from the center of gravity (approximately 2-3 cm from the navel). Since men's swimsuits must cover part or all of the leg area from the center of gravity, and women's swimsuits must cover the upper body, it is sufficient for Fabric A to cover a larger area from the center of gravity to the legs than the area used from the upper body to the center of gravity. Fabric A may be used not only as the main material of the swimsuit, but also as a lining. Competition swimsuits are preferably made with a pattern that is approximately 20% to 40% smaller than the human body.

[0110] (13-3) Buoyancy Measurement of Swimsuit The load (WA1) of the swimsuit in air was measured using a Shimadzu Corporation electronic balance, model AUY220. Next, the load (WA2) in water was measured using the buoyancy measurement method shown in Figure 4. Figure 4 is a schematic explanatory diagram showing the buoyancy measurement method. In a buoyancy test apparatus 40, water 42 was placed in a container 41, and a swimsuit (test sample 48) was placed in the water. A hanging balance (Shimadzu Corporation electronic balance, model AUY220) serving as a weigh scale 43 was fixed above the water. The test apparatus held the weigh scale 43 between a support 44 and a plate 46, and a support rod 45 and a wire mesh 47 were attached. As shown in Figure 4, the wire mesh 47 was placed in water, and the test sample 48 was suspended from the weigh scale 43 with the wire mesh 47 sandwiched between them. The load (WA2) in water (the value measured by the hanging balance) was measured. The buoyancy was calculated by subtracting WA1 from WA2.

[0111] (13-4) Examples of Swimsuits Examples of swimsuits will be described below. Note that the present invention is not limited to the following examples. In Tables 2 and 3, ◎ means optimal, ○ means suitable, and △ means unsuitable.

[0112] Men's competitive swimming swimsuits of Examples 1 to 3 and Comparative Example 1 shown in Table 2 were sewn using Fabric A and Fabric B. Each Example and Comparative Example had the mass ratio of Fabric A to Fabric B shown in the table. When these swimsuits were worn and tested, it was confirmed that the swimsuits of Examples 1 to 3 provided a more noticeable buoyancy effect, stability in a leaning position, and ease of movement compared to the swimsuit of Comparative Example 1, which did not use Fabric A, and were therefore suitable for competitive swimming.

[0113]

[0114] Similarly, fabric A and fabric B were combined to sew women's competitive swimsuits for Examples 4 to 6 and Comparative Example 2 shown in Table 3. The "center of gravity" in the table refers to the so-called center of gravity, which corresponds to the position below the navel. Furthermore, in each Example, the weight ratio of fabric A, with the center of gravity as the boundary, expressed as head to center of gravity: center of gravity to legs, was 10:90 for Example 4, 30:70 for Example 5, and 4:96 for Example 6. When these swimsuits were worn and tested, it was confirmed that the swimsuits of Examples 4 to 6 provided a more noticeable buoyancy effect, stability in a leaning posture, and ease of movement compared to Comparative Example 2, which did not use fabric A, making them suitable for competitive swimming.

[0115]

[0116] 6 to 11 show swimsuits according to first to sixth embodiments, with (A) a front view, (B) a side view, and (C) a back view, respectively. The first to third embodiments are men's swimsuits for competitive swimming, and the fourth to sixth embodiments are women's swimsuits for competitive swimming.

[0117] The first portion 3, colored gray, is made of fabric A, and the second portion 5, which is not colored, is made of fabric B. Table 4 shows the usage ratio (mass ratio) of fabric A in each embodiment. The boundary between the upper body region and the lower body region is the center of gravity (below the navel), with the upper body region corresponding to the region from the head to the center of gravity and the lower body region corresponding to the region from the center of gravity to above the knees. The boundary between the front body region and the back body region is the side seam.

[0118]

[0119] The swimsuits according to the above-described examples and embodiments are swimsuits that include, as part of a woven fabric, covering yarns, which have polyurethane elastic yarn as a core yarn and synthetic fiber filaments as sheath yarns, arranged in at least some of the warp and weft yarns.

[0120] The polyurethane elastic yarn contains 0.5 to 10 mass% of a cationic high-molecular-weight compound A having a number-average molecular weight of 2000 or more, and also contains an inorganic chlorine-based degradation inhibitor B, with the mass ratio (A / B) of the cationic high-molecular-weight compound A to the inorganic chlorine-based degradation inhibitor B being in the range of 0.3 to 3, and also contains silicone. The synthetic fiber filament is composed of synthetic fibers containing monofilaments, at least a portion of which has a plurality of grooves on its surface that are continuous in the fiber length direction, the grooves having a depth of 1.0 to 10.0 μm, an opening width of 0.5 to 10.0 μm, and a tip width of 10.0 μm or less, and a void ratio of 5 to 30% due to the cross-sectional shape of the fiber of the grooves.

[0121] The fabric includes a plain weave fabric and a weft double weave fabric with an internal void ratio of 75% or less, and the swimsuit includes a portion where the plain weave fabric and the weft double weave fabric are alternately repeated at least in a position covering the buttocks, and is water-repellent.

[0122] Under the above-mentioned premise, as shown in each embodiment, the swimsuit has a portion in which the plain weave fabric and the weft double weave fabric are alternately repeated in at least a part of the area covering from the navel to above the knees, thereby providing high buoyancy.

[0123] The alternately repeated portions of plain weave fabric and weft double weave fabric may be arranged over the entire swimsuit as in Example 1 and Embodiment 2. This allows for even greater buoyancy to be obtained.

[0124] The above-mentioned fabric may be used for the main body fabric of the swimsuit or for the lining of the swimsuit.

[0125] In particular, for swimsuits that cover only the upper body, such as men's competitive swimming swimsuits, it is preferable that the mass ratio of the above-mentioned fabric in the swimsuit is 35% or more, as shown in Table 4. Similarly, for swimsuits that cover only the upper body, it is preferable that the mass ratio of the above-mentioned fabric in the swimsuit is set in the range of front body region:back region = 4-50:50-96, as shown in Table 4.

[0126] Furthermore, for swimsuits that cover both the upper and lower body, such as women's competitive swimming swimsuits, it is preferable that the mass ratio of the woven fabric in the swimsuit be 35% or more, as shown in Table 4. Similarly, for swimsuits that cover both the upper and lower body, it is preferable that the mass ratio of the woven fabric in the swimsuit be set in the range of front body region:back region = 7-45:55-93, as shown in Table 4.

[0127] Similarly, for swimsuits that cover both the upper and lower body, it is preferable that the mass ratio of the above-mentioned fabric in the swimsuit is set in the range of upper body region: lower body region = 2 to 45: 55 to 98, as shown in Table 4, for the upper body region that covers from the head to the center of gravity and the lower body region that covers from the center of gravity to above the knees.

[0128] Although various embodiments have been described above, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above embodiments may be combined in any manner as long as they do not deviate from the spirit of the invention.

[0129] This application is based on a Japanese patent application (Patent Application No. 2023-101977) filed on June 21, 2023, the contents of which are incorporated herein by reference.

[0130] 11: Projection 12: Groove 13: Center point 14: Fiber diameter (D) 21: Straight line 22: Perpendicular line 23: Point of contact between perpendicular line 22 and fiber polymer portion 24: Width of wide portion of groove (W2) 31: Width of tip of projection (Pout) 32: Width of bottom of projection (Pmin) 40: Buoyancy test device 41: Container 42: Water 43: Weight scale 44: Support 45: Support rod 46: Support plate 47: Wire mesh 48: Test sample 51: Distribution hole for core component 52: Distribution hole for sheath component

Claims

1. A swimsuit comprising a woven fabric in which a covering yarn having a polyurethane elastic yarn as a core yarn and a synthetic fiber filament as a sheath yarn is arranged as at least a part of the warp and weft yarns, said polyurethane elastic yarn contains 0.5-10% by mass of a cationic high molecular weight compound A having a number average molecular weight of 2000 or more, and also contains an inorganic chlorine degradation inhibitor B, the mass ratio (A / B) of said cationic high molecular weight compound A to said inorganic chlorine degradation inhibitor B is in the range of 0.3-3, and also contains silicone, said synthetic fiber filaments are composed of synthetic fibers including monofilaments at least a part of which has a plurality of grooves on the surface that are continuous in the fiber length direction, said grooves having a depth of 1.0-10.0 μm, an opening width of 0.5-10.0 μm, and a protruding tip width of 10.0 μm or less, and the void ratio due to the fiber cross-sectional shape of said grooves is 5-30%, said woven fabric comprises a plain weave fabric and a weft double weave fabric, and the internal void ratio is 75% or less, The swimsuit includes a portion in which the plain weave fabric and the weft double weave fabric are alternately repeated at a position covering at least the buttocks, and is treated with a water repellent finish.

2. The swimsuit according to claim 1, wherein the portion in which the plain weave fabric and the weft double weave fabric are alternately repeated is disposed in at least a portion of the area covering from the navel to above the knees.

3. The swimsuit according to claim 1 or 2, wherein the plain weave fabric and the weft double weave fabric are alternately repeated throughout the swimsuit.

4. The swimsuit according to claim 1 or 2, wherein the woven fabric is used for the main body fabric of the swimsuit.

5. The swimsuit according to claim 1 or 2, wherein the fabric is used for the lining of the swimsuit.

6. The swimsuit according to claim 1 or 2, which covers only the upper body and the mass ratio of the woven fabric to the swimsuit is 35% or more.

7. The swimsuit according to claim 1 or 2, which is a swimsuit that covers only the upper body, and the mass ratio of the fabric in the swimsuit in the front body region and the back body region is front body region:back body region=4-50:50-96.

8. The swimsuit according to claim 1 or 2, which covers the upper and lower body and in which the mass ratio of the woven fabric in the swimsuit is 28% or more.

9. The swimsuit according to claim 1 or 2, which is a swimsuit covering the upper and lower body, and the mass ratio of the fabric in the swimsuit in the front body region and the back body region is front body region:back body region=7-45:55-93.

10. The swimsuit according to claim 1 or 2, which is a swimsuit covering the upper and lower body, and in which the mass ratio of the fabric in the swimsuit is upper body region covering from the head to the center of gravity and lower body region covering from the center of gravity to above the knees, upper body region:lower body region = 2-45:55-98.

11. The swimsuit according to claim 1 or 2, wherein the polyurethane elastic yarn has a fluorine / carbon (F / C) ratio of 0.030 or more as determined by elemental mass concentration using scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX).

12. The swimsuit as recited in claim 1 or 2, wherein the synthetic fiber filaments have 2 to 32 grooves.

13. The swimsuit according to claim 1 or 2, wherein the synthetic fiber filaments are non-crimped multifilaments.

14. The swimsuit according to claim 1 or 2, wherein the fabric has a grade of 4 or higher in the spray test described in JIS L 1092:2009.

15. The swimsuit as claimed in claim 1 or 2, wherein the fabric has a water retention rate after 60 minutes of 50% or less of the fabric weight.

16. The swimsuit as recited in claim 1 or 2, wherein the buoyancy per gram of the fabric is 0.0170 N or more.

17. The swimsuit according to claim 1 or 2, wherein the cross-sectional shape of the synthetic fibers used in the woven fabric satisfies the following (Formula 1) and (Formula 2): W2 / W1≧1.3 (Formula 1) 0.15≦H / D≦0.25 (Formula 2) W1: width of groove entrance (μm) W2: width of wide groove portion (μm) H: groove depth (μm) F: fiber diameter (μm)