Swimwear

Abstract

Provided is swimwear which satisfies the stretch characteristic, strength, ease of movement and the like required for swimwear, has superior water repellency, and reduces friction resistance between the swimwear surface and water. The woven fabric for swimwear according to the present invention has a woven structure in which core yarns are composed of elastic fibers, and covering coated threads having synthetic fiber filaments as a sheath yarn are arranged in at least a part of warp and weft yarns, wherein, in a weave diagram, the warp yarns or the weft yarns have more floating yarns. The proportion of resistance yarns perpendicular to a length (body height) direction of the swimwear is no greater than 40%, where the length (body height) direction is the direction with more floating yarns. The woven fabric is suitably used for swimwear.

Description

[Technical field]

[0001] The present invention relates to a fabric for swimsuits and a swimsuit made thereof. [Background technology]

[0002] In competitive swimming, where speed is the most important factor in breaking new records, improving the swimming technique and physical strength of the swimmers is the most important factor, but reducing the resistance of competitive swimsuits to water is also an important issue. To achieve this, efforts have been made to improve the smoothness of the surface of the swimsuit fabric and the seams.

[0003] In order to reduce frictional resistance with water, a swimsuit has been proposed that utilizes the Toms effect, in which an aqueous solution of a high molecular weight linear organic polymer is applied to the fiber surface of the swimsuit, and the polymer dissolves in water, thereby reducing frictional resistance (Patent Document 1). Although this does indeed reduce water frictional resistance, it has been pointed out that the dissolved polymer can pollute pool water.

[0004] There is also a proposal to reduce water resistance by smoothing the surface of the fabric and providing water-repellent and non-water-repellent areas, making it difficult for water to penetrate into the swimsuit while at the same time making it easier for water that has penetrated into the swimsuit to be expelled (Patent Document 2). However, because the arrangement ratio of the water-repellent and non-water-repellent areas and the shape of the swimsuit after wearing differ from person to person, unless the swimsuit is manufactured according to an individual pattern tailored to each individual, it will not be effective enough and may even have the opposite effect.

[0005] In addition, a woven swimsuit has been proposed in which the surface of the woven fabric, which uses a covering yarn with a spandex core and a synthetic sheath as the warp and weft, is smoothed and water-repellent treated, and moderate stress is applied to achieve both the movement-following ability and compression function of a swimsuit (Patent Document 3). However, it is difficult to achieve both smoothness and stretchability, and either smoothness or stretchability is often sacrificed. If smoothness is improved by calendaring or the like in order to prioritize water friction resistance, the elasticity of the thread and the slip between the woven yarns will deteriorate, resulting in a decrease in stretchability. If stretchability decreases, it will become difficult to move unless the shape of the swimsuit is individually adjusted to the wearer's body shape, hindering mobility.

[0006] Furthermore, there has been a proposal to apply a water-repellent finish to swimsuits and then blow the swimmer's breath underwater onto the swimsuit to create a thin air flow on the surface of the fabric, with the air film and bubbles reducing water friction resistance (Patent Document 4). There is also a new attempt to reduce water friction resistance by creating depressions on the back side (skin side) of a water-repellent swimsuit using a weave or embossing process, and allowing air to escape from the depressions underwater, covering the surface of the swimsuit with air bubbles (Patent Document 5).

[0007] These technologies for reducing water friction resistance using air films and air bubbles have been developed for ships, but have not yet reached a level where they can be applied to actual races as competitive swimsuits. In the technology described in Patent Document 4, in order to catch the swimmer's breath on the surface of the swimsuit, it is necessary to adjust the position where the air is exhaled in the water and the direction of the body, which cannot be done accurately during an intense race. In addition, in the technology described in Patent Document 5, the area and volume of the recesses must be increased to store air, which inevitably increases the thickness of the woven or knitted fabric, which may increase water friction resistance and even impede the mobility of the body. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 1-213403 [Patent Document 2] Japanese Patent Application Publication No. 8-311751 [Patent Document 3] JP 2011-256483 A [Patent Document 4] Japanese Patent Application Publication No. 8-41708 [Patent Document 5] International Publication No. 2012 / 073648 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention aims to solve the above-mentioned conventional problems, and to provide a swimsuit fabric that satisfies the stretch characteristics, strength, ease of movement, etc. required for a swimsuit, and reduces the water resistance experienced by the swimsuit fabric surface when swimming fast, such as in competitive swimming, and a swimsuit made thereof. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention has the following configuration.

[0011] (1) A stretch fabric in which covering yarns, which have an elastic fiber as a core yarn and a synthetic fiber filament as a sheath yarn, are arranged in at least some of the warp and weft yarns, and in which the number of floating yarns in either the warp or weft yarns is greater on the surface of the fabric, the direction in which there are more floating yarns is the length (height) direction of the swimsuit, and the ratio of resistive yarns perpendicular to the length (height) direction as shown in the following formula (I) is 40% or less. Rr = (F / P) × 100 (I) Rr: Resistance yarn ratio (%) F: The number of floating threads in a complete weave that are perpendicular to the length (height) of the swimsuit. P: Number of squares in a complete organization

[0012] (2) The stretch fabric according to the above-mentioned (1) for wearing in a swimsuit, has a total cover factor of 2800 or more as shown by the following formula (II), and the cover factor in the direction in which there are more floating warp or weft threads on the surface of the fabric and the cover factor in the direction in which there are fewer floating threads satisfy the following formula (III). cf = [√Dx × M x 〕+〔√Dy×My〕 ···(II) cfx≧cfy (III) cf: Total Coverage Factor cfx = [√Dx × M x〕 : Cover factor in the direction with more floating threads cfy = [√Dy × My]: Cover factor in the direction with the least amount of floating yarn Dx: yarn size (dtex) in the direction with more floating yarns Dy: The fineness of the yarn in the direction with the least amount of floating yarn (dtex) Mx: Weave density in the direction with the most floating threads (pieces / 2.54cm) My: Weave density in the direction with the fewest floating threads (2.54cm / piece)

[0013] (3) A woven fabric for swimsuits according to the above (1) or (2), in which the covering yarn is arranged on one of the warp yarns and the weft yarns at least on the surface of the fabric where there are more floating yarns.

[0014] (4) A woven swimsuit fabric according to any one of the above (1) to (3), wherein the synthetic fiber filaments have a plurality of grooves on the surface in the longitudinal direction of the fibers.

[0015] (5) The swimsuit fabric according to (4) above, wherein the synthetic fiber filaments have grooves with a depth of 1.0 μm to 10.0 μm, groove inlet widths of 1.0 μm to 10.0 μm, and convex portions with a width of 10.0 μm or less.

[0016] (6) A woven swimsuit fabric according to the above (4) or (5), wherein in the cross-sectional shape of the synthetic fiber filaments, the grooves have wide portions and are grooves which satisfy the following formulas (IV) and (V): (SWmax) / (SWmin)≧1.3 (IV) 0.15≦(SH / D)≦0.25 (V) (SWmin): width of groove entrance (μm) (SWmax): Width of the wide part of the groove (μm) D: Fiber diameter (μm) SH: Groove depth (μm)

[0017] (7) The woven swimsuit fabric according to any one of (1) to (6) above, wherein the synthetic fiber filaments are polyamide fibers.

[0018] (8) A fabric for swimsuits according to any one of the above (1) to (7), at least a part of which is a stretch fabric of 1 / 2 weft diagonal weave.

[0019] (9) A woven fabric for swimsuits according to any one of the above (1) to (8), at least a part of which is a stretch woven fabric of five-ply satin weave.

[0020] (10) A woven swimsuit fabric according to any one of (1) to (9) above, which has been subjected to a water-repellent treatment.

[0021] (11) A swimsuit made of the swimsuit fabric according to any one of (1) to (10) above, in which the direction with the greater number of floating threads is the length (height) direction of the swimsuit.

[0022] (12) The swimsuit according to the above (11), which is for competitive swimming. Effect of the Invention

[0023] According to the present invention, it is possible to provide a swimsuit which overcomes the above-mentioned conventional problems, satisfies the stretch characteristics, strength, ease of movement, etc. required for swimsuits, has excellent water repellency, and reduces the water resistance (resistance between the fabric surface and water) experienced by the swimsuit's fabric surface. [Brief description of the drawings]

[0024] [Figure 1] Figure 1 shows a complete diagram of the surface of a 1 / 2 weft twill weave. [Diagram 2] Figure 2 shows a complete diagram of the back side of a 1 / 2 weft diagonal weave. [Diagram 3] Figure 3 shows a complete diagram of the surface of a 2 / 1 warp twill weave. [Figure 4] Figure 4 shows a complete diagram of a plain weave. [Diagram 5] Figure 5 shows a complete diagram of the surface of a five-panel satin weave. [Figure 6] FIG. 6 is a schematic diagram showing the appearance of the circulating water channel. [Figure 7] FIG. 7 is a side view of an apparatus for explaining measurement of water friction resistance using a smooth sample plate in a circulating water tank. [Figure 8] FIG. 8 is a schematic diagram for explaining a sewing method for mounting a sample on a smooth sample plate. [Figure 9] FIG. 9 is a side cross-sectional view of an apparatus for explaining measurement of the separation angle of a boundary layer of flowing water using a cylindrical sample mounting stage in a circulating water channel. [Figure 10] FIG. 10 is a schematic diagram for explaining a sewing method for a sample to be attached to a cylindrical sample mounting stand. [Figure 11] Fig. 11a is a schematic cross-sectional view showing an example of the cross-sectional shape of a single fiber of a star-shaped cross-section yarn (V-groove) constituting the synthetic fiber multifilament used in the swimsuit fabric of the present invention. Fig. 11b is a schematic cross-sectional view showing an example of the cross-sectional shape of a single fiber of a round cross-section yarn having a narrowed groove. Figs. 11c and 11d are enlarged views of the narrowed groove portion of Fig. 11b. [Figure 12] Figure 12 shows an example of photographs evaluating the separation angle of the boundary layer of water, and Figure 12a is a photograph taken after setting up a fabric to measure the separation angle according to the measurement method for measuring the separation angle of the boundary layer of flowing water on a cylindrical sample mounting stand (10) described in the Examples. However, the room lights were on and the laser light was not irradiated. Figure 12b is a photograph taken under the same conditions with the lights off in the room turned to a dark room and the laser light irradiated (this photograph is used to measure the separation angle of the boundary layer). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The present invention will be described in detail below.

[0026] The woven fabric for swimsuits of the present invention is a woven fabric for swimsuits in which a covering yarn having a sheath yarn made of synthetic fiber filaments such as polyester filaments, polyamide filaments, polypropylene filaments, or polyethylene filaments and a core yarn made of elastic fibers such as polyurethane spandex, polyether-ester elastic fibers, polybutylene terephthalate fibers, or polytrimethylene terephthalate fibers is arranged at least as a part of the warp or weft yarns.

[0027] Among elastic fibers, covering yarns, which are made of polyurethane spandex as a core yarn and synthetic fiber filaments as a sheath yarn, are particularly preferred because they have excellent elongation and elongation recovery rates and also have the strength required for swimsuits, especially for fast swimming.

[0028] The method for producing a covering covered yarn using an elastic fiber such as spandex as a core and a synthetic fiber filament as a sheath is not particularly limited, but a covering covered yarn produced using a covering machine is preferred because it has excellent elastic fiber covering properties and is less likely to cause uneven color or gloss when woven into a fabric.

[0029] The covering method can be either single covering, in which the core yarn is covered by twisting in one direction, or double covering, in which the core yarn is covered with two sheath yarns in the S and Z directions, but in the present invention, single covering is preferred from the viewpoints of reducing the basis weight and cost. In covering, elastic fibers such as spandex are subjected to an appropriate draft, and in order to achieve high stretch performance, the draft ratio is 3 times or more, more preferably 3.5 times or more, and the upper limit is preferably 4 times or less. If the draft ratio is too low, high stretch performance cannot be obtained, and conversely, if it is too high, yarn breakage occurs during the production stage of the covered covered yarn, resulting in a low yield.

[0030] In two-way stretch fabrics using elastic fibers in both warp and weft, snags can easily become a problem when used in swimwear. Therefore, the twist factor of the covering yarn is preferably 4,500 to 15,000, and more preferably 7,500 to 12,000.

[0031] The twist factor is calculated using the following formula: Twist factor = (SS÷D+SC) 1 / 2 ×R SS: Spandex fineness (dtex) SC: Sheath thread fineness (dtex) D: Spandex draft rate (times) R: Number of coverings (T / m)

[0032] The elastic fiber of the core yarn is preferably 33 dtex or more. If only movement tracking is required, it is sufficient to have good stretchability and recovery with little force, so 22 dtex or less is fine from the perspective of weight reduction, but for swimsuits where pressure is required when worn and prevention of looseness is required, 33 dtex or more and 156 dtex or less are preferable. If the fineness is too large, the basis weight will be too large.

[0033] Preferred examples of commercially available spandex suitable for swimwear, particularly for fast swimming such as competitive swimming, include "Leuca SP" from Asahi Kasei Fibers Corporation, which has excellent chlorine resistance, and "Lycra-176B" and "Lycra-254B" from Toray Opelontech Co., Ltd.

[0034] The synthetic fiber filament used for the sheath yarn may be a filament obtained by melt spinning, such as a polyester filament, a polyamide filament, a polypropylene filament, or a polyethylene filament.

[0035] The fineness of the synthetic filament is preferably as fine as possible from the viewpoint of light weight, but if it is too fine, the strength is too low and problems with transparency occur, so it is preferably 11 dtex or more, and more preferably 16 dtex or more. If it is too thick, the basis weight becomes heavy, so it is preferably 156 dtex or less, and more preferably 110 dtex or less. From the viewpoint of productivity, the single yarn fineness of the synthetic filament is preferably 2 dtex to 6 dtex, and more preferably 3 dtex to 5 dtex. If it is thinner than 2 dtex, the cross-sectional shape tends to be too precise and complicated, resulting in a lack of production stability. If it is thicker than 6 dtex, the texture becomes rough and hard.

[0036] The cross-sectional shape of the synthetic fiber filament can be any shape, such as round, triangular, square, oval, hollow, etc., depending on the purpose. In addition, matting agents such as titanium oxide can be added as desired. Since it is used for swimwear, semi-dull or full-dull yarns with little transparency are preferably used. In addition, any yarn processing such as false twist processing using a single heater or buleria processing using a two-stage heater can be applied. From the viewpoint of imparting stretchability, false twist processed yarns are preferred.

[0037] In addition, in swimsuit applications where the blending ratio of elastic fibers is high (15% or more), some elastic fibers, such as spandex made of polyurethane, may have problems with sublimation of disperse dyes and deterioration of color fastness due to contamination, so polyamide filaments using acid dyes can be used more preferably as sheath yarns than polyester filaments, which are mainly dyed with disperse dyes. Polypropylene filaments and polyethylene filaments have the problem of not being dyeable, and basically there is the inconvenience of using dope-dyed yarns with pigments. The problem of color fastness can also be improved by using polyester dyeable with cationic dyes.

[0038] Furthermore, in the present invention, the weave structure is important. It is necessary to use a weave structure in which either the warp or weft threads have a large number of floating threads, and the ratio of resistive threads perpendicular to the direction in which the floating threads are more prevalent (resistive thread ratio) must be at least 40% or less, and 35% or less is more preferable. The resistive thread ratio is expressed by the following formula. Rr = (F / P) × 100 Rr: Resistance yarn ratio (%) F: The number of floating threads in a complete weave that are perpendicular to the length of the swimsuit (pieces) P: Number of squares in a complete organization

[0039] When considering the frictional resistance between the surface of a swimsuit and water during competitive swimming, the woven threads of the fabric used in the swimsuit that are parallel to the direction of swimming, i.e. the length of the swimsuit, have a small frictional resistance to water, but the higher the proportion of resistive threads arranged perpendicular to the direction of swimming, the greater the frictional resistance to water.

[0040] In the case of plain weave used in conventional competitive swimsuits, the resistance thread ratio is 50%, with half of the threads arranged parallel to the swimming direction and half arranged perpendicular to it. If the resistance thread ratio is higher than 50% due to the weave structure, the water friction resistance between the surface of the fabric and the water increases, affecting the speed during competitive swimming and causing poor records. As long as the warp and weft threads can cross and maintain the shape of the fabric, the smaller the resistance thread ratio, the better, but if it is too small, the number of crossing points between the warp and weft threads decreases, causing twisting of the weaving threads. Furthermore, the crimp rate of the weaving threads becomes unstable, and conversely, the water friction resistance may increase, so the resistance thread ratio is preferably in the range of 40 to 10%, and more preferably in the range of 35 to 15%.

[0041] In addition, in the case of a covering yarn obtained using a covering machine, the synthetic fiber filaments of the sheath yarn are wound around the core yarn with an oblique twist angle relative to the direction of the weaving yarn due to the influence of the number of twists in the twisting yarn. Therefore, when viewed alone, the sheath yarn is not exactly parallel to the traveling direction due to the influence of the twist angle, but if it is used as a covering yarn for the entire weaving yarn so that it is parallel to the traveling direction, the water friction resistance will be low.

[0042] The calculation method of the resistance thread ratio will be explained in more detail using the complete weave diagram of 1 / 2 weft twill weave in Figure 1. A complete weave is the smallest unit of the basic weave of a fabric, and this weave is repeated front to back and left to right. In addition, weave stitches where the warp thread is above the weft thread (floating warp thread) are painted black. Weave stitches where the warp thread is below the weft thread (floating weft thread) are shown in white. The weave of the 1 / 2 weft twill weave in Figure 1 is a complete weave with 9 squares of 3 warp threads and 3 weft threads. There are 9 complete squares, and the direction with the most floating threads is the weft direction. Therefore, if the weft direction is the length (height) direction of the swimsuit, the number of squares of the resistance thread perpendicular to the weft direction is 3, which is the warp thread painted black. Therefore, the resistance thread ratio (Rr) is 33.3% as shown in the following formula. This calculation result can be used as an index of water friction resistance. Since this is lower than 40%, this fabric can reduce water friction resistance by using the weft direction, which has more floating threads, in the length direction of the swimsuit. F: Number of floating threads in a single weave perpendicular to the length of the swimsuit (height): 3 P: Number of squares in one complete organization: 9 Rr=(F / P)×100=(3 / 9)×100=33.3%

[0043] If the fabric in Figure 1 is turned over and the reverse side is used as the front side of the swimsuit, the weave diagram will have a twill line going up and to the left as shown in Figure 2, and as before, it will have a complete weave with 9 squares of 3 warp threads and 3 weft threads. However, if the weft direction is used on the front side of the swimsuit in the length (stretch) direction, the number of black squares of resistance threads perpendicular to the length (height) direction will be 6. Therefore, the resistance thread ratio will be 66.6%. The ratio of threads parallel to the swimming direction will decrease, and the ratio of threads perpendicular to the swimming direction will increase, resulting in a large water friction resistance. In this case, instead of using the weft direction on the front side of the swimsuit in the length (height) direction, the resistance thread ratio will be the same as in Figure 1 by using the warp direction of the fabric on the front side of the swimsuit in the length (height) direction. In the case of twill or satin weave, the resistance thread ratio will be reversed when using the fabric on the front side and the reverse side, so care must be taken when sewing swimsuits. When using the reverse side of a weft-diagonal woven fabric on the front side of a swimsuit, the warp direction of the fabric should be in the length (height) direction of the swimsuit, resulting in a resistant thread ratio of 33.3% and low friction resistance. When cutting the fabric and cutting off each sewn part, the length direction should be reversed from warp to weft, and the warp direction should be in the length (height) direction of the swimsuit, allowing it to be used as a low friction woven fabric.

[0044] Also, in the case of the 2 / 1 warp twill weave in Figure 3, if the warp direction with more floating threads is used in the length (height) direction of the swimsuit, the resistance thread ratio will be 33.3%. However, if the weft direction is used in the length (height) direction of the swimsuit, the resistance thread ratio will be 66.6%. Therefore, water friction resistance can be reduced by using the warp direction in the length (height) direction of the swimsuit.

[0045] In the case of twill or satin weaves, it is important to determine whether the fabric will be used on the front or back, and whether the warp or weft will run along the length (height) of the swimsuit.

[0046] Incidentally, weft twill weave is the name for a fabric in which the weft threads are more visible on the surface, and warp twill weave is the name for a fabric in which the warp threads are more visible on the surface; both are alternative names for twill weave.

[0047] Similarly, in twill fabrics, the floating and sinking of the warp and weft threads are reversed depending on whether it is on the front or back. In the present invention, it is important that the ratio of resisting threads perpendicular to the direction in which there are more floating threads is 40% or less, and that the direction in which there are more floating threads is used in the length (height) direction of the swimsuit fabric, and in order to satisfy this requirement, the front and back and the warp and weft of the fabric are selected for production so that the parts can be easily cut off when sewing, thereby reducing manufacturing costs.

[0048] A complete weave diagram of a plain weave is shown in Figure 4. The total number of squares in a complete weave is 4, and the number of squares for resistance yarns perpendicular to the direction in which there are more floating yarns is 2. In the case of plain weave, the resistance yarn ratio is 50% in all directions, face, back, warp, and weft, and water friction resistance is high.

[0049] A complete weave diagram of a five-ply twill fabric is shown in Figure 5. In this case, by orienting the warp threads in the direction of the water flow, i.e., in the length direction (body height), the resistance thread ratio becomes 20%, and water friction resistance can be reduced.

[0050] In the present invention, the weave is not limited to twill or satin weave, and any weave such as day and night weave or variegated weave can be used as long as the resistance yarn ratio is 40% or less. From the viewpoint of design and pattern, even in dobby or jacquard fabrics that combine plain weave, twill and satin weave parts, the frictional resistance between the surface of the fabric and water can be reduced by setting the resistance yarn ratio perpendicular to the direction in which there are many floating threads in a complete weave to 40% or less and using the direction in which there are many floating threads in the length (height) direction of the swimsuit.

[0051] Furthermore, by keeping the total area of ​​the resistant yarn ratio of each woven part used in one swimsuit to 40% or less, water friction resistance can be kept low, thereby achieving the object of the present invention.

[0052] In the present invention, the total cover factor represented by the following formula is preferably 2800 or more. If the total cover factor is small, the number of crossing points decreases, and the weaving yarn is less restrained, which can cause problems such as twisting and snagging, so the cover factor is more preferably 3000 or more. Even more preferably, it is 3200 or more. cf = [√Dx × M x 〕+〔√Dy×My〕 ···(II) cfx≧cfy (III) cf: Total Coverage Factor cfx = [√Dx × M x 〕: Cover factor in the direction with more floating threads cfy = [√Dy × My]: Cover factor in the direction with the least amount of floating yarn Dx: Fineness of yarn in the direction with more floating yarns: Fineness (dtex) of covering yarn with spandex as core yarn and synthetic fiber filament as sheath yarn Dy: Fineness in the direction with fewer floating yarns: Fineness (dtex) of covering yarn with spandex as core yarn and synthetic fiber filament as sheath yarn Mx: Weave density in the direction with the most floating threads (pieces / 2.54cm) My: Weave density in the direction with the fewest floating threads (2.54cm / piece)

[0053] From the viewpoint of further reducing the frictional resistance between the fabric surface and water, it is preferable to make the cover factor in the direction in which there are more floating warp or weft threads on the fabric surface larger than the cover factor in the direction in which there are fewer floating threads, and it is preferable to satisfy formula (III).

[0054] The direction with the most floating threads is the direction with the most floating threads on the surface of the fabric in a complete weave diagram. Therefore, depending on the weave and the front and back of the fabric, it may be the warp direction or the weft direction. In particular, when sewing, it is important to be careful to use the direction with the most floating threads on the surface in the length (height) direction of the swimsuit.

[0055] By making the cover factor in the length (height) direction larger than the cover factor in the width direction, which is perpendicular to the length (height) direction, combined with the effect of lowering the resistance yarn ratio to 40% or less as mentioned above, water friction resistance is further reduced.

[0056] More preferably, the cover factor in the direction with more floating threads divided by the total cover factor should be 55% or more to further reduce water friction resistance. Even more preferably, it should be 60% or more. However, if it is too large, the warp and weft balance of the fabric will be poor, and the fabric will be prone to twisting and misalignment, and the warp and weft balance of the stretch power will be poor when used as a swimsuit.

[0057] The warp fineness and weft fineness shown in the above formula are the total fineness after the yarn consisting of a combination of a core yarn and a sheath yarn is woven into a fabric and dyed. When a single yarn is used without a covering yarn, the fineness is the fineness after the single yarn is woven into a fabric and dyed, and when paralleled yarns or ply-twisted yarns are used, the fineness is the fineness after the paralleled yarns or ply-twisted yarns are woven into a fabric and dyed. In other words, the apparent fineness is measured by disassembling the final woven fabric and taking out the fibers using the method described in the Examples.

[0058] Similarly, the weave density is the density of the fabric after it has been woven and dyed.

[0059] In addition, when the density of a fabric such as ripstop is partially changed into coarse and dense parts, the low water resistance that is the object of the present invention can be obtained by setting the density of the part of the fabric that occupies 50% or more of the area of ​​a complete fabric part within the above-mentioned range.

[0060] When two or more types of covering yarns are arranged and used as weaving yarns, the total cover factor and the cover factor described above can be calculated using the fineness and density calculated by simply averaging the number and fineness of the fibers arranged in one complete weave portion.

[0061] Even when the weave is partially changed due to dobby weaving, jacquard weaving, etc., the frictional resistance between the surface of the fabric and water can be reduced by making the total cover factor of the complete fabric 2800 or more, making the cover factor in the length (height) direction greater than the cover factor in the width direction perpendicular to the length (elongation) direction, and making the ratio of resisting yarns perpendicular to the direction with the most floating yarns 40% or less.

[0062] The weight of the swimsuit fabric of the present invention is preferably as light as possible, but from the viewpoint of transparency and strength, it is preferably 50 g / m 2 It is preferable that the thickness is 70 g / m or more. 2 More than 200g / m is preferable. Since the heavier the material, the greater the water resistance, the greater the resistance to water. 2 It is preferable to do the following:

[0063] The thickness of the woven fabric for swimsuits of the present invention is preferably as thin as possible, but is preferably 0.15 mm or more, more preferably 0.2 mm or more, from the viewpoints of transparency and strength. Also, since a thicker fabric increases water resistance, it is preferably 0.7 mm or less. The woven fabric for swimsuits of the present invention is preferably water-repellent treated. The water-repellent agent used in the water-repellent treatment may be any of fluorine-based, silicone-based, paraffin-based, and the like, but among them, 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 are unlikely to generate perfluorooctanoic acid (PFOA) are more preferred. Furthermore, in consideration of the market demand for fluorine-free fabrics, it is more preferred to use C0 water-repellents, either alone or in combination, of silicone-based or paraffin-based water-repellents.

[0064] In order to improve the durability of the water repellency, it is preferable to use a crosslinking agent in combination with the water repellent. As the crosslinking agent, at least one of melamine resins, blocked isocyanate compounds, glyoxal resins, imine resins, etc. can be used, and the crosslinking agent is not particularly limited.

[0065] Furthermore, in the present invention, the frictional resistance between the woven fabric surface and water can be further reduced by using a synthetic fiber filament having a plurality of grooves on the surface in the longitudinal direction of the fiber as a sheath yarn and a covering yarn having an elastic fiber as a core yarn. The cross-sectional shape and the number of grooves of the synthetic fiber filament having a plurality of grooves can be set arbitrarily, but from the viewpoints of cost and production stability, a round cross section with 6 to 15 grooves is preferable, and 6 to 10 grooves is even more preferable.

[0066] 11a and 11b are schematic cross-sectional views showing examples of the cross-sectional shapes of the monofilaments constituting the synthetic multifilament fiber used in the swimsuit fabric of the present invention. Fig. 11a shows a so-called eight-lobed star-shaped cross section, with V-groove gaps 13 formed by eight lobe convex portions composed of polymer portions 14 and adjacent concave portions.

[0067] FIG. 11b shows a round cross section having a constricted groove, which will be described later, and has a polymer portion 14 and a gap portion 13 of the constricted groove, similar to the star-shaped cross section.

[0068] Furthermore, the synthetic fiber filament having a plurality of grooves on the longitudinal surface of the fiber can be easily produced by dissolving the easily soluble component and forming slit-shaped grooves using fibers produced by core-sheath composite spinning using two-component polymers, which will be described later. This method is preferable because it allows for the production of precise cross-sectional shapes. It is also possible to produce a modified cross-section yarn using a modified cross-section spinneret for one-component melt spinning.

[0069] The depth of the groove in the cross-sectional shape of the synthetic fiber filament is preferably 1.0 μm to 10.0 μm. If it is shallower than 1.0 μm, the water repellency improvement effect due to the lotus effect is difficult to manifest, and if it is deeper than 10.0 μm, the strength of the fiber is reduced. The depth of the groove (star-shaped cross section) 17 of the star-shaped cross-section yarn is defined as the depth of the gap from the intersection of the straight line 15 connecting the ends of the convex parts present on either side of the groove to the center point 12 of the cross section perpendicular to the longitudinal direction of the synthetic fiber filament with the straight line 15 connecting the ends of the convex parts on the line 16 and the perpendicular line 16 to the polymer part 14 of the fiber. The center point is defined as the center point of the circle that circumscribes the tip of the convex part most frequently with two or more points in the cross section that is the cross section of the fiber polymer.

[0070] The groove width is preferably 1.0 μm to 10.0 μm. If it is narrower than 1.0 μm, the lotus effect is unlikely to be exhibited, and if it is wider than 10.0 μm, water is likely to penetrate into the uneven grooves. The groove width is defined as the length of a straight line 15 connecting the ends of adjacent convex portions observed when observing a cross section, which is a cross section of the fiber polymer perpendicular to the longitudinal direction of the synthetic fiber filament.

[0071] Furthermore, the width of the convex portion formed between two adjacent grooves is defined as the length 25 of the straight line connecting the protrusion 24, which is the end of the convex portion on the groove A side, and the protrusion, which is the end of the convex portion on the groove side adjacent to groove A, sandwiching the convex portion, in the case of a round cross section having a narrowed groove as shown in FIG. 11d. Note that in the star-shaped 8-lobe cross section as shown in FIG. 11a, the protrusions, which are the ends of both convex portions, approach or overlap, and as a result, the width of the convex portion is close to 0. From the viewpoint of water friction resistance, it is preferable that the width of the convex portion is as close to 0 as possible, and it is desirable that the convex portion is apex-shaped.

[0072] The grooves on the fiber surface form unevenness on the fiber surface, and high water repellency is expressed by the lotus effect described below. The grooves are filled with air in water, and the solid walls of the fiber surface do not touch the water due to the air film, so there is no water friction resistance with the fiber. Only a part of the solid walls of the convex parts touches water on the fiber surface. Water friction resistance is reduced by making the convex parts that touch water as small as possible. However, if the convex parts have acute angles, the fiber surface is fibrillated due to friction between the fiber surface and various solid surfaces when worn, and single yarn cracks are likely to occur. Since cracks are likely to occur and the fiber surface becomes white, the width of the convex parts is preferably 1.0 μm or more, and preferably 10.0 μm or less. If the width of the convex parts is wider than 10.0 μm, it becomes difficult to express the lotus effect described below, and it becomes difficult to maintain high water repellency. For products that are conscious of wear durability, it is preferable to widen the width of the convex parts to improve wear resistance. In addition, when speed records are more important than wear durability for competitive use, the width of the convex parts can be set arbitrarily according to the purpose, such as by making them smaller.

[0073] In the present invention, as the synthetic fiber filament having a plurality of grooves on the fiber surface, it is also preferable to use a synthetic fiber filament having a narrowed groove in order to make it difficult for water to penetrate into the uneven grooves and to prevent fibrillation due to wear. As the narrowed groove, for example, a groove having a wide portion on the outer periphery of a single fiber when observing a cross section perpendicular to the longitudinal direction of the fiber is preferably mentioned, and a plurality of such grooves are preferably present.

[0074] Specifically, synthetic fiber filaments can be preferably used in which the groove entrance width (SWmin), the width of the wide portion of the groove (SWmax), and the groove depth (SH) relative to the fiber diameter (D) satisfy the following formula:

[0075] The narrowed type referred to here means a form in which the width of the internal space of the groove is wider than the width of the groove entrance on the fiber surface in the cross section of the fiber (an example is shown in Figure 11b). (SWmax) / (SWmin)≧1.3 0.15≦(SH / D)≦0.25

[0076] In the above, the width of the groove entrance (SWmin), the width of the wide portion of the groove (SWmax), the fiber diameter (D), and the groove depth (SH) are determined as follows.

[0077] That is, the groove entrance width (SWmin) is defined as the length of the straight line 15 connecting the ends of adjacent convex parts observed when observing the cross section, which is the cross section of the fiber polymer perpendicular to the fiber direction of the synthetic fiber filament, like the entrance width of the V-shaped groove of the star-shaped cross section yarn shown in Figure 11a above. Therefore, in the case of a narrowing type groove, it is the length connecting the ends of the protrusions of adjacent convex parts. In addition, the groove wide part width 18 (SWmax)) is the maximum point when the length perpendicular to the center line of the groove is measured along the center line 19 from the outer periphery toward the center of the fiber. The diameter of the circumscribing circle 22 of the convex part is the fiber diameter (D) 20. In addition, the groove depth 21 (SH) of a round cross section yarn having a narrowing type groove means the distance between the intersection points of the circumscribing circle 22 of the convex part and the inscribing circle 23 of the groove part on the center line of the groove. The circumscribing circle 22 referred to here is the true circle that circumscribes the tip of the convex portion at the cross section of the core-sheath composite fiber at the most two or more points, and the inscribing circle 23 refers to the true circle that inscribes the tip (bottom) of the groove portion at the most two or more points.

[0078] As the circular cross section having a narrowed groove of the present invention, a synthetic fiber filament having an internal gap width of the groove that satisfies the following formula can be preferably used. That is, a synthetic fiber filament can be used in which the end of the protrusion forming the entrance of the groove is an acute angle, and the width between adjacent protrusions (Pout), the width of the entrance of the groove (SWmin), and the width of adjacent protrusions (Pout) and the width of the bottom surface of the adjacent groove (Pmin) satisfy the following formula. The width of the protrusion (Pout) refers to the distance between the tip of one protrusion 24 of a certain groove and the tip of the protrusion closer to the protrusion 24 of the protrusion of the adjacent groove, which is indicated by the width 25 of the convex portion in FIG. 11d. The width 26 (Pmin) of the bottom surface of the adjacent groove means the distance between the points corresponding to the contact points with the inscribed circles 23 of the adjacent grooves across the protrusion. (Pout) / (SWmin)=2~10 (Pout) / (Pmin)≧1.3

[0079] The synthetic fiber filaments having these grooves can be obtained by dissolving the sheath component of the fiber produced by the core-sheath composite spinning as described above, using a solvent. As the core component, polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyamide, etc. can be used. As the sheath component, from the viewpoint of simplifying the dissolving process, copolymerized polyesters, polylactic acid, polyvinyl alcohol, etc. that are easily soluble in aqueous solvents or hot water are preferred, and in particular, polyesters and polylactic acids copolymerized with polyethylene glycol or sodium sulfoisophthalic acid alone or in combination are preferred from the viewpoint of ease of handling and easy dissolution in aqueous solvents.

[0080] In particular, when false twisting is performed, by performing false twisting on sheath-core composite fibers that contain eluted components and then dissolving the eluted components in the dyeing process after weaving, the grooves are not crushed during false twisting and the slit portions of the grooves can be maintained even in the textured yarn. Although slit yarns can be obtained by normal spinning without using a composite spinning machine, the grooves are often crushed during false twisting. In sheath-core composite fibers in which the grooves are filled with eluted components, the grooves are prevented from being crushed even during false twisting, and the shape of the grooves is maintained by dissolving the eluted components in the dyeing process after weaving.

[0081] The preferred method of dissolving and dyeing is to scour, relax and dry the grey fabric, then heat fix the width with an intermediate set, and dissolve the groove components. After that, dye it, reduce and wash it if it is made of polyester, or fix it if it is made of nylon, rinse it with hot water, and dry it. Next, water repellent treatment and various functional treatments are applied as necessary, and the fabric is finished and set.

[0082] In addition, since the woven fabric of the present invention uses elastic fibers such as polyurethane spandex in combination as the core yarn, it is preferable to use polyamide that can be dyed with acid dyes that cause few problems in the dyeing process.

[0083] For the dyeing process after the fabric is made, if the synthetic fiber filament used for the covering yarn is a core-sheath composite fiber, a conventional method can be used, taking into consideration the elution of sheath components and the use of elastic fibers such as spandex. For example, the scouring and relaxing process is performed by maintaining the fabric in an open state and adjusting the temperature and width conditions in about three stages to prevent the occurrence of wrinkles, and then fixing the width with a tenter, and removing the sheath polymer of the core-sheath composite fiber with a caustic soda solution or the like to create grooves in the synthetic fiber. After that, the fabric is dyed, fixed, dried, water-repellent, and finished and set to obtain a woven fabric for swimsuits.

[0084] In addition to the unevenness of the woven fabric surface due to the weave and the unevenness between the single yarns of the fiber threads, more complex unevenness can be expressed by providing slit-like grooves on the fiber surface. As explained by the Wenzel formula below, when the contact angle of the fiber surface is 90° or more, the more uneven the material's surface becomes, the larger the apparent contact angle becomes, and the easier it is to repel water. This effect is called the lotus effect. "Wenzel's formula" r×cosθ=cosθ' r: true surface area / apparent surface area θ: True contact angle θ': Apparent contact angle

[0085] However, when worn as swimsuits, the woven fabric stretches in the warp and weft directions, the unevenness caused by the structure of the woven fabric and between the single yarns of the fiber yarns is flattened to an infinitesimal extent, the lotus effect is minimized, and the swimsuit becomes less water-repellent than before it was worn. In particular, in recent years, in order to increase the surface smoothness of the woven and knitted fabrics used in swimsuits for competitive swimming, there is a tendency to deliberately wear swimsuits one size smaller when wearing them for competitive swimming, etc., where swimming speed is required, and this phenomenon results in the surface unevenness of the woven and knitted fabric being reduced, resulting in a decrease in the apparent water repellency.

[0086] However, by providing multiple grooves on the fiber surface, it is possible to suppress the decrease in water repellency even when the woven fabric is stretched. Even if the woven fabric crimp or crimp due to yarn processing is stretched by wearing, the woven fabric structure or processed yarn structure is stretched and flattened, but the multiple grooves provided on the fiber surface themselves are not stretched and flattened, so the lotus effect can be maintained and the water repellency can be maintained at a high level.

[0087] In a particularly preferred embodiment of the present invention, the synthetic fiber filaments of the sheath yarn are made of fibers having a plurality of grooves on the surface in the longitudinal direction of the fibers, which are preferably used for at least a portion of the warp and weft yarns, and are preferably used so as to be arranged on the surface of the fabric, and particularly preferably used in the direction in which there are more floating warp or weft yarns. In other words, by using them in the length (body height) direction of the fabric used in swimsuits, the grooves on the fiber surface are arranged parallel to the direction of movement when swimming, i.e., the direction of the water flow, and the effect of reducing the frictional resistance between the surface of the swimsuit fabric and water can be further increased.

[0088] The above-mentioned fibers have grooves formed in the longitudinal direction thereof and are treated to be water repellent. When the fibers are submerged in water, the inside of the grooves is filled with air, forming an air film.

[0089] For this reason, the water flow on the fiber surface of the swimsuit is suspended in mid-air above the air film in the grooves, as if it were slipping, and the frictional resistance is smaller than that of the surrounding non-grooved fiber surface, making the water flow faster than the layer of water on the non-grooved fiber surface. As a result, the slow-moving water on the fiber surface is caught up in the water flow above the air film in the uneven grooves. It is believed that the water flowing on the non-grooved fiber surface flows onto the air film in the grooves, where it repeatedly collides and disperses.

[0090] Repeated collisions and dispersion as described above promote turbulence, which suppresses separation of the water boundary layer on the surface of the swimsuit, similar to the dimple effect that occurs in the depressions of a golf ball, and reduces geometric (pressure) resistance.

[0091] The separation angle of the boundary layer of water, which shows this phenomenon, can be measured by placing a cylindrical sample stand in the circulating water tank shown in the examples and attaching a cylindrical textile sample to the sample stand. Figure 6 is a schematic diagram showing the concept of the circulating water tank. The circulating water tank is composed of two water tanks, one above the other, and two pipes for circulating the water in the tanks. The arrows in Figure 6 indicate the direction of the water flow. A few grams of nylon microparticles are mixed into the circulating water tank as tracer microparticles, and the circulating water tank is placed in a darkroom state and irradiated with laser light to photograph the separation angle of the boundary layer of water from the cylindrical sample for comparative evaluation (an example is shown in Figure 12b). Figure 12 is a photograph of an example of the evaluation of the separation angle of the boundary layer of water, and Figure 12a is a photograph taken after setting the textile to measure the separation angle according to the measurement method described in the examples, "(10) Measurement of the separation angle of the boundary layer of flowing water on a cylindrical sample mounting stand." However, the room lights are on and laser light is not irradiated. Figure 12b is a photograph taken in the same condition with the lights off in the room turned off and the room darkened, and then irradiated with laser light (this photograph is used to measure the boundary layer separation angle). Figures 12a and 12b show the surface 27 seen from above the cylindrical sample mounting stand, and the boundary layer separation angle of water is measured as the boundary layer separation angle 28, which is the angle between a line parallel to the flow passing through the center point of the circle as seen from above the circular sample mounting stand placed in the water flowing from right to left, which is the direction indicated by the arrow in Figure 12b, and a line connecting the center point to the separation point of the flow. The measurement conditions such as water temperature and flow speed are the same (the Reynolds number is the same), and the measurements are performed with different textile samples, and the separation angles 28 can be compared and evaluated. A larger separation angle 28 indicates a state in which boundary layer separation is suppressed, and vortices are less likely to form in the wake of the flow, which reduces negative pressure and, as a result, reduces shape (pressure) resistance.

[0092] In the example, in the case of Example 1, in which a woven fabric satisfying the specifications of the present invention was set on a cylindrical sample mounting stand 5 (diameter: 7.5 cm, height: 28.0 cm), the flow velocity was 1.0 m / sec (Reynolds number: 8.3×10 4) had a boundary layer peel angle of 124°, while in the case of Comparative Examples 1, 2, and 3, which used fabrics with a resistance yarn ratio of 50% or more, which does not satisfy the provisions of the present invention, the boundary layer peel angle measured under the same conditions was 113 to 120°, which is smaller. In other words, the shape (pressure) resistance was larger. In particular, Comparative Example 3, which had the highest resistance yarn ratio of 66.6%, had the smallest boundary layer peel angle of 113° and the highest shape (pressure) resistance.

[0093] At the same time, the water friction resistance was 7.0 N / m 2 In comparison, Comparative Examples 1, 2, and 3 are 7.4 to 7.8 N / m 2 and is becoming higher.

[0094] As is known from the dimple effect of golf balls, the boundary layer peel angle increases when there are appropriate unevenness and depressions, and the shape resistance (pressure resistance) decreases. However, when there are unevenness and depressions, the surface becomes less smooth and the surface area becomes larger than when there are no unevenness and depressions, so the friction resistance increases. The friction resistance, which is greatly influenced by the smoothness of the surface, and the shape (pressure) resistance, which is influenced by the boundary layer peel angle due to moderate unevenness, are contradictory characteristics. However, the swimsuit fabric of the present invention, which has a resistance yarn ratio of 40% or less, has a reduced shape (pressure) resistance effect in addition to a reduced friction resistance. Furthermore, when a fiber with a groove formed in the length direction and a water-repellent finish is used, an air layer is formed in the groove, and water slides over the air layer, which effectively reduces the friction area with the fiber surface, thereby reducing the friction resistance and the shape resistance (pressure resistance).

[0095] That is, it is particularly effective in women's swimwear, where the difference in cross-sectional area of ​​the human body in the direction of movement during competitive swimming is particularly large. By arranging fabrics with a large number of floating threads in the direction of movement in areas where the boundary layer of the water is likely to separate, such as the chest, waist, and buttocks, it is possible to reduce not only frictional resistance but also shape (pressure) resistance.

[0096] It is preferable that the covering yarn, which has an elastic fiber as a core yarn and a synthetic fiber filament as a sheath yarn, is arranged in the warp or weft yarn in the direction where there are more floating yarns at least on the surface of the fabric, and that the direction in which there are more floating yarns is the length (height) direction of the swimsuit, in order to extremely reduce frictional resistance and shape (pressure) resistance.Furthermore, it is even more preferable to use a covering yarn, which uses a synthetic fiber filament with uneven grooves as a sheath yarn and an elastic fiber such as spandex as a core yarn, in the direction in which there are more floating yarns, and to use that direction in the traveling direction of the fabric, in order to further reduce frictional resistance and shape (pressure) resistance.

[0097] In addition, in the case of the woven fabric of the present invention, which has the property of reducing both resistance forces, namely water friction resistance and shape (pressure) resistance, which is determined by the boundary layer separation angle, with one material, when sewing into a swimsuit, it can be applied to all parts of the swimsuit with one material regardless of the part, making it easy to use and the material part This eliminates the need for switching and reduces the number of seams.

[0098] Conventionally, materials with low friction resistance were selected for the relatively smooth parts of the body in water during competitive swimming, from the abdomen to the waist and the front of the thighs, while materials that prevent boundary layer separation were selected for parts that change shape significantly, such as the chest and buttocks, where boundary layers separate and shape resistance (pressure resistance) increases. In this case, the material must be changed and the number of seams increases, which causes an increase in water resistance. The swimsuit fabric of the present invention, which can reduce seams, is preferable because it also has the effect of reducing resistance caused by seams.

[0099] The swimsuit fabric of the present invention has excellent stretch properties that allow it to shape the body and reduce frictional resistance between the surface of the fabric and water. Furthermore, the grooves in the synthetic fiber filaments retain air to form an air film, which increases the separation angle of the water boundary layer, thereby reducing shape resistance (pressure resistance). Therefore, the swimsuit fabric of the present invention can be suitably used in swimsuits such as racing swimsuits and wet suits. EXAMPLES

[0100] The present invention will be described in more detail 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.

[0101] (1) Weight The basis weight was measured in accordance with JIS L1096:2010, 8.3.2, Method A, under standard conditions (20°C, 65% RH). Three test pieces measuring 200 mm x 200 mm were taken, and the mass (g) of each was measured after leaving them for one day under standard conditions. The mass per unit area was calculated using the following formula: 2 Mass per unit (g / m 2 ) and calculate the average, then round it to one decimal place. Sm=W / A Here, Sm: mass per unit area under standard conditions (g / m 2 ) W: Mass of the test piece under standard conditions (g) A: Area of ​​the test piece (m 2 )

[0102] (2) Thickness The thickness was measured in accordance with 8.4 of JIS L1096:2010, using a thickness gauge to measure the thickness of five different points of the humidity-conditioned sample of Method A under a pressure of 23.5 kpa at a constant pressure after 10 seconds, and the average value was calculated.

[0103] (3) Resistance yarn ratio From a complete weave diagram of a fabric, fill in the squares where the warp thread is above the weft thread and leave the squares where the warp thread is below the weft thread white. Then check the direction in which there are many floating threads. If there are many floating weft threads, count the number of squares (F) that are perpendicular to the length direction, with the weft direction being the length (height) direction. Then count all the squares (P) and calculate the resisting thread ratio using the following formula. Rr = (F / P) × 100 Rr: Resistance yarn ratio (%) F: The number of floating threads in a complete weave that are perpendicular to the length (height) of the swimsuit. P: The number of all squares in a complete organization (units)

[0104] (4) Cover factor (4-1) Apparent fineness of textile decomposition yarn The warp and weft threads are extracted from the woven fabric, and their apparent fineness is measured in accordance with "Method of measuring the apparent fineness of fibers extracted from fabric" in Appendix H of JIS L1096:2010.

[0105] In the case of processed products with resin coating or film laminate, the measurement shall be made according to the method described in "Chapter 3 Measurement of apparent fineness of fibers taken out from fabric after removing non-fibrous substances" after removing non-fibrous substances according to the method described in ISO1833-1. In the case of dyed and finished products without resin processing (including water repellent and softening processing), the measurement shall be made according to the method described in "Chapter 2 Measurement of apparent fineness of fibers taken out from fabric without removing non-fibrous substances".

[0106] However, the mass of the yarn is measured after adjusting it to moisture equilibrium under standard conditions (20°C, 65% RH) (Method A) and calculated using the following formula. The number of measurements should be 40 or more. Ld = Ws / L × n Ld: Apparent fineness (tex) of yarn adjusted under standard conditions Ws: Mass of thread removed from fabric (g) L: Average length when pulled straight (m) n: Number of weighed yarns

[0107] In the case of covered yarn, the apparent fineness is measured in the covered state without separating the yarn pulled out from the fabric into the elastic fiber core yarn and the synthetic fiber filament sheath yarn.

[0108] (4-2) Density The density of a fabric is measured by measuring the number of threads per cm using Method B (fabric disassembly spectrometer) in Appendix F of JIS L1096:2010, and converting it to per inch (2.54 cm).

[0109] The number of measurements for both warp and weft is the average of three.

[0110] (4-3) Cover factor The apparent fineness and density are calculated by substituting the measurement results of the apparent fineness and density into the following formula. cf = [√Dx × M x 〕+〔√Dy×My〕 cf: Total Coverage Factor cfx = [√Dx × M x 〕: Cover factor in the direction with more floating threads cfy = [√Dy × My]: Cover factor in the direction with the least amount of floating yarn Dx: yarn size (dtex) in the direction with more floating yarns Dy: The fineness of the yarn in the direction with the least amount of floating yarn (dtex) Mx: Direction with more floating threads Weaving Density (book / 2.54cm) My: Weave density in the direction with the fewest floating threads (2.54cm / piece)

[0111] (5) Depth of grooves on the surface of single fiber yarns, width of protrusions, and width of groove openings (μm) (SWmax): width of the wide part of the groove, diameter of the fiber (μm), (SWmax) / (SWmin) (ratio of width of the wide part of the groove / width of the groove entrance) The cross section of the yarn was photographed at 1500x magnification using a scanning electron microscope (Hitachi High-Technologies Corporation, S-3400N type). During the photographing, the height of the uneven parts, the interval between adjacent convex parts, the width of the convex parts, etc. were instructed to be measured. Measurements were made to the nearest 0.01 μm, rounded to one decimal place, and expressed as the average value of 10 measurement results.

[0112] (6) Water repellency The water repellency is measured according to JIS L1092:2009 7.2 Water Repellency Test (Spray Test), by collecting three samples of approximately 200mm x 200mm, and using a water repellency tester, 250ml of water is placed in a funnel so that the sample's longitudinal direction is parallel to the water flow, and sprayed onto the sample for 20 to 25 seconds. Next, the sample holder is removed from the device, one end is held horizontally, and the front side of the test piece is turned downwards, the other end is lightly placed against a hard object once to allow water droplets to fall, and the other end is rotated 180°, and the same operation as before is repeated to allow excess water droplets to fall. The wet state of the sample is compared with that of the control sample while still attached to the holder, and judged.

[0113] The washing was carried out in accordance with the washing conditions specified in JIS L0001-2014, code number 142 (C4M method), using a pulsator-type washing machine with mild agitation conditions and a washing water temperature of 40°C. The water repellency of the sample was measured before washing and after 20 washes. Grade 1: The entire surface is moistened. Grade 2: Half of the surface is wetted, with small individual spots wetting the fabric. Grade 3: The surface is filled with small individual droplets of moisture. Grade 4: The surface does not get wet, but small water droplets are attached. Grade 5: No moisture or water droplets on the surface.

[0114] (7) Elongation rate The elongation was measured in accordance with JIS L1096:2010, 8.14 Tensile elongation A method (cut strip method). That is, from a sample conditioned to a standard temperature and humidity condition, three test pieces each of 50 mm wide × 300 mm long were taken in the warp direction and weft direction, and the elongation was calculated using a constant-speed extension tensile tester at a grip interval of 200 mm, a tensile speed of 200 mm / min, and a load of 14.7 N according to the following formula. Ep = (L1-L) / L Ep: Elongation at constant load (%) L: Length between the original marks (mm), 200mm L1: Length when loaded with 14.7N (mm)

[0115] (8) Abrasion resistance evaluation For the abrasion test, an appearance retention type tester as described in JIS L1076:2012 "Pilling test method for woven and knitted fabrics" was used, and the bottom area of ​​the upper holder was set to approximately 13 cm. 2 The friction speed was set to 90 rpm, the pressure load was set to 7.36 N, and the test fabric was fixed on the upper holder and the lower friction plate and abraded for 10 minutes. After abrasion, the surface change of the fabric set on the upper holder and the occurrence of fibrillation were observed with a stereomicroscope.

[0116] (9) Measurement of water friction resistance on a smooth sample mounting plate The water friction resistance was measured when the swimsuit fabric was stretched by 15% in both the direction of running water and perpendicular to the direction of running water, using the circulating water tank shown in Figure 7. Figure 7 is a side view of an apparatus for explaining the measurement of water friction resistance using a smooth sample plate in a circulating water tank, and Figure 8 is a schematic diagram for explaining the sewing method of the sample attached to the smooth sample plate.

[0117] First, the fabric sample was cut into a rectangle with a length of 0.867 m (height in the swimsuit) and a width of 0.634 m (width in the swimsuit). Next, the fabric sample was folded in half at the center of the width 7 (width) as used for the swimsuit, with the surface facing inward, as shown in Figure 8a, and then stacked. The vertical edge 8 to be sewn in the length 6 (height) as used for the swimsuit was overlocked with nylon processed thread to create a bag shape with a seam allowance of 0.6 cm, as shown in Figure 8b.

[0118] The sewn seam is pressed with an iron on one side, and then turned inside out so that the seam is inside the bag-shaped sample, with the surface of the woven fabric being the front side of the woven fabric sample. A sample fixing line 9 is marked with an oil-based marker or the like 10 cm from the top. A stainless steel smooth sample mounting plate 1 (draft depth: 0.25 m, length: 1.0 m, thickness: 0.006 m) is then inserted from the opening 10 of the bag-shaped sewn sample, and set while stretching it so that it covers the smooth sample mounting plate 1.

[0119] By aligning the sample fixing line 9 marked on the top of the sample with the sample fixing position on the smooth sample mounting plate 1, the sample fabric is stretched by 15% in both the direction of the flowing water and the direction perpendicular to the direction of the flowing water. In this state, the upper open opening 10 is fixed to the stainless steel smooth sample mounting plate 1 with a rubber band or clip. A load cell (stress meter) 2 capable of measuring the shear stress of the smooth plate and the water flow is attached to the part where the smooth sample mounting plate is fixed.

[0120] The circulating water tunnel has a wave-breaking lid with several holes of about 5 cm in diameter, and also has a long hole of 1.1 m in length and 0.015 m in width so that the top of the stainless steel smooth sample mounting plate does not touch the lid. Water is poured up to about 3 to 5 cm above the lid. The lid prevents waves from being generated in front of the smooth plate even when the water flow speed of the circulating water tunnel is increased, and the frictional resistance of the smooth plate covered with the textile sample can be measured without being affected by waves.

[0121] The water flow rate of the circulating water tank can be set as desired by rotating a screw built into the bottom of the tank. The flow rate can also be measured by a Pitot tube 3 attached to the tank. A water thermometer is also attached so that the water temperature can be measured. In this state, the circulating water tank is placed in a room where the temperature and humidity can be set as desired. The water temperature in the tank can be set as desired by adjusting the temperature and humidity in the room.

[0122] The water temperature is set to 25° C., the flow rate is set to 2.0 m / sec, and the total resistance (RT) of the smooth sample mounting plate 1 covered with the fabric sample is measured.

[0123] Three bag-shaped woven fabric samples were prepared, and the resistance force at a flow velocity of 2.0 m / s was measured three times. The average value of the measured data was calculated, and the value converted into the draft area of ​​both sides using the following formula was determined as the friction resistance force RF (unit: N / m 2 ) RF=(RT-RD) / A RF: Frictional resistance force (N / m 2 ) A: Total surface area of ​​the wetted parts of the flat plate 0.25×1.0+0.25×1.0=0.5m 2 (m 2 ) RT: Total resistance force of the flat plate with the fabric sample attached (N) RD: Resistance increase due to thickness (N) RD = 0.486 × ρ x V 2 / 2 ρ: Density of water at 25°C 997 (kg / m 3 ) x: Projected area of ​​the plane perpendicular to the flow (thickness x draft) 0.006 x 0.25 = 0.0015 m 2 (m 2 ) V: Water speed 2.0 (m / sec)

[0124] The Reynolds number, which indicates the state of fluid flow, was calculated using the following formula. Re=VL / ν Re: Reynolds number (-) V: average velocity of the fluid (m / sec) L: Characteristic length: Length of the plate (m) ν: Dynamic viscosity coefficient of water (m 2 / sec)

[0125] (10) Measurement of boundary layer separation angle of flowing water on a cylindrical sample mounting platform Using the same circulating water tank as used to measure water friction resistance, the separation angle of the boundary layer of flowing water was measured when the swimsuit fabric was stretched by 15% in both the direction of flowing water and perpendicular to the direction of flowing water, using an apparatus in which a cylindrical sample mounting stand 5 (diameter: 7.5 cm, height 28.0 cm) made of polyvinyl chloride resin as shown in Figure 9 was attached to the top cover 4 at the center of the tank. Figure 9 is a side cross-sectional view of the apparatus for explaining the measurement of the separation angle of the boundary layer of flowing water using a cylindrical sample mounting stand in a circulating water tank.

[0126] The top lid 4 has several holes of about 5 cm in diameter, and water is poured into it up to about 3 to 5 cm above the position of the top lid 4. The top lid 4 is used to eliminate the effects of wave-making resistance, and the presence of this top lid 4 makes it possible to prevent waves from being generated even when the water flow speed of the circulating water tank is increased, thereby eliminating the effects of waves.

[0127] First, the fabric sample is cut into a rectangle measuring 21.7 cm in the length (body height) direction 6 used for the swimsuit and 29.3 cm in the width (width) direction 7 used for the swimsuit. Next, the fabric surface is placed inside and folded in half at the center of the width (width) direction 7 used for the swimsuit as shown in Figure 10a, and after overlapping, a seam allowance of 0.6 cm is added to the end 8 to be sewn in the width (width) direction 7 used for the swimsuit as shown in Figure 10b, and the fabric is sewn into a tube shape with both the top and bottom open 11 using overlock sewing thread made of nylon.

[0128] The seam is pressed with an iron on one side, and the seam is turned inside out to place it inside the cylindrical sample, so that the surface of the woven fabric becomes the front side of the woven fabric sample. In addition, a sample fixing line 9 is marked with a permanent marker or the like 5.0 cm below the woven fabric sample for alignment to the cylindrical sample mounting stand 5. Then, the cylindrically sewn sample is stretched to cover the cylindrical sample mounting stand 5 and set. The end of the woven fabric sample is aligned with the upper end of the cylindrical sample mounting stand 5 and firmly fixed with a rubber band. Next, the sample fixing line 9 marked on the woven fabric sample is aligned with the lower end of the cylindrical sample mounting stand 5 and firmly fixed with a rubber band. In this state, the sample woven fabric is stretched by 15% in both the direction of the running water and the direction perpendicular to the running water direction.

[0129] The water tank was the same as that used for the friction resistance measurement using the smooth sample mounting plate 1, and the handling method was the same.

[0130] The separation angle of the boundary layer of the flowing water is measured when the water temperature is 25°C and the flow rate is 1.0 m / sec. Under normal lighting conditions, it is difficult to see the separation state of the boundary layer of the water as in the photograph shown in Figure 12a. Therefore, an appropriate amount of tracer particles (polyamide 10 μm particles, specific gravity 1.02) is added to the flowing water, the lights in the room in which the circulating water tank is installed are turned off to create a darkroom state, and then a laser beam (PIV Laser G150, manufactured by Kato Koken) is irradiated from the outside of the transparent window of the circulating water tank in a direction that slices the cylindrical sample mounting stand 5. A camera is set above the circulating water tank to photograph the flowing water state near surface 27 as seen from the top of the cylindrical sample mounting stand as shown in Figure 12b. Note that the exposure of the camera and the shutter The speed is adjusted appropriately. As shown in Figure 12b, the angle between a line parallel to the flow passing through the center point of the circle and a line connecting the center point to the flow separation point is defined as the boundary layer separation angle 28.

[0131] Three cylindrical woven fabric samples were prepared, and measurements were carried out three times. The average value of the measurement data was calculated to obtain the boundary layer peel angle (°).

[0132] The Reynolds number, which indicates the state of fluid flow, was calculated using the following formula. Re=VL / ν Re: Reynolds number (-) V: average velocity of the fluid (m / sec) L: characteristic length: diameter of cylinder (m) ν: Dynamic viscosity coefficient of water (m 2 / sec)

[0133] [Example 1] For the warp yarn, a chlorine-resistant Lycra "Lycra-25B" 44dtex (PU44) from Toray Opelontech was used as the core yarn, and a 17dtex, 7 filament semi-dull, round cross-section nylon false twisted yarn (nylon yarn 1) was used as the sheath yarn to produce a single covering yarn with a draft ratio of 3.5 times the core yarn, a twist number of 1800T / M, and a twist factor of 9788. For the weft yarn, a chlorine-resistant Lycra "Lycra-25B" 33dtex (PU33) was used as the core yarn, and a 17dtex, 7 filament semi-dull, round cross-section nylon false twisted yarn (nylon yarn 1) was used as the sheath yarn, the same as the warp yarn, to produce a single covering yarn with a twist number of 1900T / M and a twist factor of 9768. A 1 / 2 weft twill fabric was produced on a rapier loom, and the same weave was subjected to three-stage relaxation scouring in an open state, and then preset. The fabric was then dyed with an acid dye in a jet dyeing machine and dried.The fabric was then immersed in a non-fluorine water repellent treatment solution of the following formulation, squeezed out with a mangle at a squeezing rate of 60%, dried at 130°C for 2 minutes, and further subjected to a final set at 160°C without applying any extra tension, which also served as curing.

[0134] The fabric obtained had a warp density of 216 threads / 2.54 cm and a weft density of 270 threads / 2.54 cm. In a complete weave, the number of warp threads floating was 3 and the number of weft threads floating was 6, resulting in a 1 / 2 weft twill fabric as shown in Figure 1.

[0135] By using the weft direction in the length (height) direction of the swimsuit, a swimsuit fabric with low water friction resistance was obtained. The cover factor, basis weight, thickness, water repellency, and elongation of the obtained fabric were measured, and a bag-shaped sample was made from the obtained fabric, which was stretched by 15% in both the direction of running water and perpendicular to the direction of running water, wrapped around a smooth sample plate, and covered with a circulating water tank to measure water friction resistance. A cylindrical sample was also made in the same manner, which was stretched by 15% in both the direction of running water and perpendicular to the direction of running water, and a cylindrical sample mounting stand was covered with the sample, and the boundary layer separation angle was measured. The evaluation results are shown in Table 1.

[0136] The abrasion resistance evaluation showed no problems at all, and the friction resistance with water was also low, making it an excellent fabric for use as competition wear or practice swimwear.

[0137] [Water-repellent treatment formula] "Neoseed" NR-158 (manufactured by Nicca Chemical Co., Ltd.) 5% by weight "Beckamin" M-3 (DIC) 0.3% by weight "Catalyst" ACX (DIC) 0.3% by weight Isopropyl alcohol 1% by weight Treatment solution mixed with 93.5% water by weight

[0138] [Example 2] The core component was nylon 6, which had a star-shaped core as shown in Figure 11a, and the sheath component was polyethylene terephthalate (melt viscosity: 45 Pa s) copolymerized with 8.0 mol % 5-sodium sulfoisophthalic acid and 10 wt % polyethylene glycol with a molecular weight of 1,000. Eight V-shaped grooves were formed near the outer periphery of the cross section perpendicular to the longitudinal direction of a single core-sheath composite fiber, yielding a core-sheath composite fiber (star-shaped composite yarn 1) of 56 dtex 18 filaments (core 30 wt %, sheath 70 wt %, 16.8 dtex 18 filaments after dissolution of the sheath component). Next, a single covering yarn was produced using two parallel sheath yarns and a core yarn made of chlorine-resistant Lycra "Lycra-25B" 33 dtex (PU33) from Toray Opelontech Co., Ltd., with a draft ratio of 3.5 times the core yarn, a twist number of 1480 T / M, and a twist coefficient of 16280 (however, the twist coefficient after dissolution of the sheath component of the composite spinning is 9768). Using the single covering yarn as the warp and weft, a 1 / 2 weft twill fabric was produced on a rapier loom in the same manner as in Example 1, and the same fabric was subjected to three-stage relaxation scouring in the spread-out state, and then preset. Next, a liquid jet dyeing machine was used to remove 100% of the polyethylene terephthalate component with a 1 wt% sodium hydroxide aqueous solution, and a fabric was obtained using the star-shaped cross-section yarn shown in Figure 11b as the sheath yarn and the covering covering yarn using polyurethane spandex as the core yarn as the warp and weft. Thereafter, the fabric was dyed with an acid dye in a jet dyeing machine and then dried. Next, the fabric was immersed in the same non-fluorine-containing water-repellent treatment liquid as in Example 1, and squeezed out at a squeezing rate of 60% using a mangle. The fabric was then dried at 130°C for 2 minutes, and further subjected to a final set at 160°C without applying any unnecessary tension, which also served as curing.

[0139] The fabric obtained had a warp density of 208 threads / 2.54 cm and a weft density of 220 threads / 2.54 cm. In a complete weave, the number of floating warp threads was 3 and the number of floating weft threads was 6, resulting in a 1 / 2 weft twill fabric with the weave diagram shown in Figure 1.

[0140] The grooves on the cross section of the core-sheath composite fiber after the sheath component was dissolved were observed with a scanning electron microscope, with the following results.

[0141] There were eight grooves, the groove entrance was a V-shaped groove with a width of 9.2 μm, the fiber diameter was 18.5 μm, the groove depth was 6.1 μm, and it had the desired shape to maintain a large amount of air layer. In addition, the protrusions had a sharp acute angle, and the width of the protrusions (apexes) was almost nonexistent, being essentially 0 μm.

[0142] By using the weft direction in the length (height) direction of the swimsuit, a swimsuit fabric with low water friction resistance was obtained. The cover factor, basis weight, thickness, water repellency, elongation rate, etc. of the obtained fabric were measured, and a bag-shaped sample was made from the obtained fabric, and the weft direction of the fabric was set in the running water direction. Flow direction and The sample was stretched by 15% in both the direction of the water flow and the direction perpendicular to the water flow, and the smooth sample plate was wrapped and covered to measure the water friction resistance using a circulating water tank. A cylindrical sample was also made in the same manner, and the sample was stretched by 15% in both the direction of the water flow and the direction perpendicular to the water flow, and the sample was covered on a cylindrical sample mounting base to measure the boundary layer separation angle. The evaluation results are shown in Table 1.

[0143] When an abrasion resistance evaluation was carried out, some fibrillation was found in the protrusions, but the grooves on the yarn surface of the fabric were large, and the friction resistance with water and the boundary layer peeling angle were large, making it the best in terms of low water resistance. Although the abrasion resistance is somewhat inferior, it is an excellent fabric for use in competitive swimsuits for top athletes.

[0144] [Example 3] A nylon 6 core component and polyethylene terephthalate (melt viscosity: 45 Pa s) copolymerized with 8.0 mol% 5-sodium sulfoisophthalic acid and 10 wt% polyethylene glycol with a molecular weight of 1000 were used as the sheath component, and a core-sheath composite fiber of 84 dtex·24 filaments (core 80 wt%, sheath 20 wt%, 67 dtex·24 filaments after sheath component elution) was obtained in such a way that one core-sheath composite fiber had eight narrow grooves with a narrow groove entrance and a wide groove interior, as shown in Figure 11b. Next, a textured yarn (narrowed composite yarn 2) that had been false-twisted using the core-sheath composite fiber was used as the sheath yarn, and a chlorine-resistant Lycra "Lycra-25B" 78 dtex (PU78) from Toray Opelontech was used as the core yarn to produce a single covering yarn with a draft ratio of 3.5 times the core yarn, a twist number of 1035 T / M, and a twist factor of 9780. The single covering yarn was used as the warp and weft to produce a 1 / 2 weft twill fabric using a rapier loom in the same manner as in Example 1, and the fabric was subjected to three-stage relaxation scouring in an open state and then preset. Next, using a liquid jet dyeing machine, 100% of the polyethylene terephthalate component was removed with a 1% by weight aqueous solution of sodium hydroxide to obtain a 100% nylon fabric. After that, the fabric was dyed with an acid dye using a liquid jet dyeing machine and then dried. Next, the fabric was immersed in the same non-fluorine water repellent treatment solution as in Example 1, squeezed with a mangle at a squeezing rate of 60%, dried at 130°C for 2 minutes, and further subjected to a final set at 160°C without applying any extra tension, which also served as curing.

[0145] The fabric obtained had a warp density of 138 threads / 2.54 cm and a weft density of 144 threads / 2.54 cm. In a complete weave, the number of floating warp threads was 3 and the number of floating weft threads was 6, resulting in a 1 / 2 weft twill fabric as shown in Figure 1.

[0146] The grooves on the cross section of the core-sheath composite fiber after the sheath component was dissolved were observed with a scanning electron microscope, with the following results.

[0147] There were eight grooves, the groove entrance width was 0.9 μm, and the width of the wide part of the groove was 1.6 μm (SWmax / SWmin: 1.8), and the groove entrance was narrow and widened toward the center of the fiber cross section. The fiber diameter was 15.9 μm and the groove depth was 3.1 μm (SH / D: 0.19), which was the desired shape that could adequately maintain an air layer. The width of the protrusions was 7.8 μm. When the abrasion resistance was evaluated, no peeling or collapse of the protrusions was observed, and no fibrillation was observed on the sample surface, even when forced abrasion was applied.

[0148] By using the weft direction in the length (height) direction of the swimsuit, a swimsuit fabric with low water friction resistance was obtained. The cover factor, basis weight, thickness, water repellency, elongation rate, etc. of the obtained fabric were measured, and a bag-shaped sample was made from the obtained fabric, and the weft direction of the fabric was set in the running water direction. Flow direction and The sample was stretched by 15% in both the direction of the water flow and the direction perpendicular to the water flow, and the smooth sample plate was wrapped and covered to measure the water friction resistance using a circulating water tank. A cylindrical sample was also made in the same manner, and the sample was stretched by 15% in both the direction of the water flow and the direction perpendicular to the water flow, and the sample was covered on a cylindrical sample mounting base to measure the boundary layer separation angle. The evaluation results are shown in Table 1.

[0149] It has no problems with abrasion resistance, and the surface of the woven yarn has narrow, uneven grooves that trap air even underwater, which increases the friction resistance with water and the boundary layer separation angle, making it an excellent competitive swimwear that combines low water resistance and durability.

[0150] [Example 4] For the warp yarn, Toray Opelontech's chlorine-resistant Lycra "Lycra-25B" 44 dtex (PU44) was used as the core yarn, and 33 dtex, 24 filament semi-dull, round cross-section nylon false twist textured yarn (Nylon Yarn 2) was used as the sheath yarn. A single covering yarn with a core draft rate of 3.5 times, twist number of 1500 T / M, and twist coefficient of 9780 was produced. For the weft, two single covering yarns obtained in Example 2, i.e., 56 dtex·18 filaments (core 30wt%, sheath 70wt%, 16.8 dtex·18 filaments after sheath component elution) core-sheath composite fibers (star-shaped composite yarn 1) were used as the sheath yarns, and the core yarns were made of chlorine-resistant Lycra "Lycra-25B" 33dtex (33PU) from Toray Opelontech Co., Ltd., with a core draft ratio of 3.5 times and a single covering yarn with a twist number of 1480T / M and a twist coefficient of 16280 (however, the twist coefficient after elution of the sheath component of the composite spun yarn is 9768), were used, and a five-ply satin fabric was produced on a rapier loom. Thereafter, the raw fabric was subjected to three-stage relaxation scouring in the open state and then preset in the same manner as in Example 2. Next, 100% of the polyethylene terephthalate component was removed from the sea with a 1% by weight aqueous solution of sodium hydroxide using a liquid jet dyeing machine to obtain a 100% nylon fabric. Thereafter, the fabric was dyed with an acid dye in a jet dyeing machine, dried, and then immersed in a non-fluorine water repellent treatment solution. The fabric was squeezed out with a mangle at a squeezing rate of 60%, and then dried at 130°C for 2 minutes. Furthermore, a final set was performed at 160°C without applying any extra tension, which also served as a curing process, to obtain a 5-ply satin fabric with a warp density of 206 threads / 2.54cm, a weft density of 190 threads / 2.54cm, 20 warp floats and 5 weft floats in one complete weave, as shown in Figure 5.

[0151] By using the warp direction in the length (height) direction of the swimsuit, a swimsuit fabric with low water friction resistance was obtained. The cover factor, basis weight, thickness, water repellency, and elongation of the obtained fabric were measured, and a bag-shaped sample was made from the obtained fabric, which was stretched by 15% in both the direction of running water and perpendicular to the direction of running water, wrapped around a smooth sample plate, and covered with a circulating water tank to measure water friction resistance. A cylindrical sample was also made in the same manner, which was stretched by 15% in both the direction of running water and perpendicular to the direction of running water, and a cylindrical sample mounting stand was covered with the sample to measure the boundary layer separation angle. The evaluation results are shown in Table 1.

[0152] When an abrasion resistance evaluation was carried out, some fibrillation was found in the protrusions, but the yarn length of the yarn parallel to the water flow direction was long and there were grooves, and the ratio of resisting yarns perpendicular to the water flow direction was low at 20%, so the friction resistance with water and the boundary layer separation angle were large, making it excellent from the perspective of low water resistance. Although the abrasion resistance is slightly inferior, it is an excellent fabric for use in competitive swimsuits for top athletes.

[0153] [Comparative Example 1] A plain weave fabric with a warp density of 240 threads / 2.54 cm and a weft density of 230 threads / 2.54 cm was obtained in the same manner as in Example 1, except that the weave structure of Example 1 was changed to a plain weave and the density was changed. The cover factor, basis weight, thickness, water repellency, and elongation of the woven fabric were measured in the same manner as in Example 1, and further, the water friction resistance of a smooth sample plate and the boundary layer separation angle were measured using a cylindrical sample mounting stand with the weft direction in the swimsuit length (height) direction using a circulating water tank. The evaluation results are shown in Table 1.

[0154] [Comparative Example 2] A plain weave fabric with a warp density of 143 threads / 2.54 cm and a weft density of 140 threads / 2.54 cm was obtained in the same manner as in Example 3, except that the sheath yarn of the single covering yarn was a 67 dtex, 24 filament semi-dull, round cross section nylon false twist textured yarn (nylon yarn 3) and the weave was plain weave. The cover factor, basis weight, thickness, water repellency and elongation of the woven fabric were measured in the same manner as in Example 3, and further the water friction resistance of a smooth sample plate and the boundary layer separation angle of a cylindrical sample mounting stand were measured using a circulating water tank with the weft direction aligned in the height direction (length) of the swimsuit. The evaluation results are shown in Table 1.

[0155] [Comparative Example 3] A 2 / 1 warp twill fabric with a warp density of 216 threads / 2.54 cm and a weft density of 270 threads / 2.54 cm was obtained in the same manner as in Example 1, except that the weave of Example 1 was changed to a 2 / 1 warp twill fabric and the density was changed. The cover factor, basis weight, thickness, water repellency, and elongation of the fabric were measured in the same manner as in Example 1, and the water friction resistance of a smooth sample plate and the boundary layer separation angle were measured using a cylindrical sample mounting stand with the weft direction in the swimsuit length (height) direction using a circulating water tank. The evaluation results are shown in Table 1.

[0156] [Table 1]

[0157] [Table 2] [Explanation of symbols]

[0158] 1: Smooth sample mounting plate 2: Load cell (stress meter) 3: Pitot tube 4:Top lid 5: Cylindrical sample mounting stand 6: Length (height) direction used for swimsuits 7: Body width (width) direction used for swimsuits 8: Edges to be sewn 9: Sample fixing line 10: Open mouth 11: Both top and bottom are open 12: Center point 13:Void part 14: Polymer part 15: Straight line 16: Vertical line 17: Groove depth (star-shaped cross section) 18: Width of the wide part of the groove 19: Center line 20: Fiber diameter 21: Groove depth (round cross section with narrowed groove) 22: Circumscribed circle 23: Inscribed circle 24:Protrusion 25: Width of the convex part 26: Width of bottom of groove 27: Top view of the cylindrical sample mounting stand 28: Peel angle

Claims

1. The swimsuit is a stretch fabric in which covering covering yarns, which have an elastic fiber as a core yarn and a synthetic fiber filament as a sheath yarn, are arranged on at least some of the warp and weft yarns, and the weave structure has a greater number of floating yarns on the surface of the fabric, either the warp or the weft yarns, and the direction in which there are more floating yarns is the length (height) direction of the swimsuit, and the swimsuit is composed of a swimsuit fabric in which the ratio of resistive yarns perpendicular to the length (height) direction as shown in the following formula (I) is 40% or less, and the direction in which there are more floating yarns is the length (height) direction of the swimsuit. Rr=(F / P)×100...(I) Rr: Resistance yarn ratio (%) F: The number of floating threads in a complete weave perpendicular to the length (height) of the swimsuit P: Number of squares in a complete organization

2. 2. The swimsuit according to claim 1, wherein the stretch fabric has a total cover factor of 2800 or more as shown by the following formula (II), and the cover factor in a direction in which there are more floating warp or weft threads on the surface of the fabric and the cover factor in a direction in which there are fewer floating threads satisfy the following formula (III). cf=[√Dx×Mx]+[√Dy×My]...(II) cfx≧cfy...(III) cf: total cover factor cfx = [√Dx x Mx]: Cover factor in the direction with more floating threads cfy = [√Dy x My]: Cover factor in the direction with the least amount of floating yarn Dx: Fineness of the weaving yarn in the direction with more floating yarns (dtex) Dy: Fineness (dtex) of the weaving yarn in the direction with the least amount of floating yarn Mx: Weave density in the direction with more floating threads (pieces / 2.54 cm) My: Weaving density in the direction with the fewest floating threads (pieces / 2.54 cm)

3. 3. The swimsuit according to claim 1, wherein the covering yarn is arranged on one of the warp yarns and the weft yarns at least on the surface of the fabric where there are more floating yarns.

4. The swimsuit according to any one of claims 1 to 3, wherein the synthetic fiber filaments have a plurality of grooves on the surface in the longitudinal direction of the fibers.

5. 5. The swimsuit according to claim 4, wherein the synthetic fiber filaments have a groove depth of 1.0 μm to 10.0 μm, a groove entrance width of 1.0 μm to 10.0 μm, and a convex portion width of 10.0 μm or less.

6. 6. The swimsuit according to claim 4 or 5, wherein in the cross-sectional shape of the synthetic fiber filaments, the groove portion has a wide portion and is a groove that satisfies the following formulas (IV) and (V): (SWmax) / (SWmin)≧1.3 (IV) 0.15≦(SH / D)≦0.25 (V) (SWmin): groove entrance width (μm) (SWmax): Width of the wide part of the groove (μm) D: Fiber diameter (μm) SH: Groove depth (μm)

7. The swimsuit according to any one of claims 1 to 6, wherein the synthetic fiber filaments are polyamide fibers.

8. The swimsuit according to any one of claims 1 to 7, wherein at least a part of the weave is a stretch fabric of 1 / 2 weft diagonal weave.

9. The swimsuit according to any one of claims 1 to 8, wherein at least a part of the weave is a stretch fabric of five-ply satin weave.

10. The swimsuit according to any one of claims 1 to 9, which has been subjected to a water-repellent treatment.

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