Mesh fabric

Abstract

Provided is a mesh fabric that allows isotropic deformation under the action of an external load. In the mesh fabric comprising warp yarns and weft yarns, bending angles of the warp yarns and the weft yarns at intersection parts where the warp yarns and the weft yarns intersect are different from each other. The ratio of the absolute value of the difference between the bending angles of the warp yarns and the weft yarns to the average value of the bending angles of the warp yarns and the weft yarns is 20% or less. At least one of the warp yarns and the weft yarns may be made of synthetic fibers.

Description

Technical Field

[0001] The present invention relates to a mesh fabric which allows isotropic deformation. Background Art

[0002] In salt electrolyzers, water electrolyzers, etc., ion exchange membranes are used for various ion exchanges. Ion exchange membranes are mostly required to have high durability and high mechanical strength for various solvents and high temperature environments. Therefore, a method for strengthening ion exchange membranes by compounding a resin with ion permeability and a support body composed of a mesh-like object or a nonwoven fabric is adopted.

[0003] Patent Document 1 describes that the strength of an ion exchange membrane can be improved by using a reinforcing material (woven fabric or nonwoven fabric) formed of reinforcing fibers such as polytetrafluoroethylene (PTFE).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2000-297164 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] It is known that ion exchange membranes deform under external loads such as heat and external force. Here, if the reinforcing material (woven fabric) of the ion exchange membrane deforms anisotropically due to the external load, the stress acting on the ion exchange membrane becomes uneven and the stress is concentrated on a part of the ion exchange membrane, thereby possibly damaging the ion exchange membrane.

[0009] An object of the present invention is to provide a mesh fabric that allows isotropic deformation when subjected to external loads.

[0010] Solutions for solving problems

[0011] The gist of the present invention is as follows.

[0012] [1] A mesh fabric, characterized in that it is a mesh fabric comprising warp yarns and weft yarns,

[0013] The bending angles of the warp and weft threads at the intersections of the warp and weft threads are different from each other.

[0014] The ratio of the absolute value of the difference between the bending angles of the warp and the weft to the average value of the bending angles of the warp and the weft is 20% or less.

[0015] [2] The mesh fabric according to [1], characterized in that it satisfies at least one of the following conditions:

[0016] The ratio of the absolute value of the difference between the tensile strength in the warp direction and the tensile strength in the weft direction to the average value of the tensile strength in the warp direction and the weft direction is 20% or less;

[0017] The ratio of the absolute value of the difference between the tensile elongation in the warp direction and the tensile elongation in the weft direction to the average value of the tensile elongation in the warp direction and the weft direction is 68% or less; and

[0018] Regarding the slope in the elastic deformation region of the curve representing the relationship between the tensile load and the tensile elongation ratio, the ratio of the absolute value of the difference between the above-mentioned slopes in the warp direction and the weft direction to the average value of the above-mentioned slopes in the warp direction and the weft direction is 62% or less.

[0019] [3] The mesh fabric according to [1] or [2], characterized in that the ratio of the absolute value of the difference between the thermal deformation in the warp direction and the thermal deformation in the weft direction to the average value of the thermal deformation in the warp direction and the weft direction is 180% or less.

[0020] [4] The mesh fabric according to [1], wherein at least one of the warp yarns and the weft yarns is a synthetic fiber.

[0021] [5] The mesh fabric according to [4], characterized in that the synthetic fiber is PE fiber, PTFE fiber, PPS fiber, LCP fiber or PEEK fiber.

[0022] Effects of the Invention

[0023] According to the present invention, the warp and weft bending angles are different from each other, and the absolute value of the difference between the warp and weft bending angles relative to the average value of the warp and weft bending angles is set to 20% or less, thereby making it easier to allow the mesh fabric to deform isotropically. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a diagram for explaining the bending angle of the warp yarn. DETAILED DESCRIPTION

[0025] The mesh fabric as an embodiment of the present invention is described below. The mesh fabric is a fabric composed of a plurality of warp yarns and a plurality of weft yarns. In this embodiment, as described later, by focusing on the bending angles of the warp yarns and the bending angles of the weft yarns, the mesh fabric can be allowed to deform isotropically.

[0026] The use of the mesh fabric is not particularly limited, and for example, the mesh fabric can be used as a reinforcing material for an ion exchange membrane. According to this embodiment, when an external load such as heat or external force acts on the mesh fabric, the mesh fabric is allowed to deform isotropically, thereby suppressing stress concentration on a part of the mesh fabric. The mesh fabric of this embodiment can be used for articles (products) for the purpose of suppressing stress concentration caused by external loads.

[0027] The loom used for manufacturing the mesh fabric is not particularly limited, and for example, a shuttle loom, a projectile loom, a rapier loom, a water jet loom, or an air jet loom can be used. The mesh fabric manufactured by the loom can be subjected to a heat treatment (heat setting).

[0028] The bending angle of the warp refers to the angle at which the warp is bent at the intersection of the warp and the weft. The bending angle of the warp can be measured by cutting the intersection of the warp and the weft along the length direction of the weft (hereinafter referred to as "weft direction") and observing the cut surface using a microscope (e.g., an optical microscope). Figure 1 A schematic diagram showing a cut surface when measuring the bending angle of a warp. Figure 1 In the middle, 1 warp thread 1 Figure 1 The three wefts 2a, 2b, and 2c are arranged at predetermined intervals. Figure 1 The wefts 2a, 2b, and 2c are in the left and right directions. Figure 1 Extending in a direction perpendicular to the plane of paper.

[0029] Figure 1 The angle θ shown is the bending angle of the warp yarn 1 at the intersection of the warp yarn 1 and the weft yarn 2a. The bending angle θ is the angle (acute angle) formed by the straight line L1 connecting the two reference points P1 and P2 and the straight line L2 connecting the two reference points P1 and P3. If the reference points P1 to P3 are identified by microscopic observation of the above-mentioned cut surface, the bending angle θ can be measured based on the straight lines L1 and L2.

[0030] Reference point P1 is a point at the intersection of warp 1 and weft 2a, where the radius of curvature of warp 1 is the smallest, and is located at the radial center of warp 1. Reference point P2 is a point at the intersection of warp 1 and weft 2b (the weft adjacent to weft 2a), where the radius of curvature of warp 1 is the smallest, and is located at the radial center of warp 1. Reference point P3 is a point at the intersection of warp 1 and weft 2c (the weft adjacent to weft 2a), where the radius of curvature of warp 1 is the smallest, and is located at the center of warp 1.

[0031] The bending angle of the weft refers to the angle at which the weft is bent at the intersection of the warp and the weft. The bending angle of the weft can be measured by cutting the intersection of the warp and the weft along the length direction of the warp (hereinafter referred to as the "warp direction") and observing the cut surface with a microscope (such as an optical microscope). Similar to the above-mentioned method for measuring the bending angle of the warp, three reference points P1 to P3 can be specified in the cut surface, and the bending angle of the weft can be measured based on the straight lines L1 and L2. That is, at Figure 1 In the embodiment, if the warp yarn 1 is replaced by the weft yarn and the weft yarns 2a to 2c are replaced by the warp yarns, the bending angle θ of the weft yarns can be measured.

[0032] As described above, if the warp bending angle θ1 and the weft bending angle θ2 are measured at the intersection of the warp and the weft, the bending angle difference Δθ can be obtained. The bending angle difference Δθ is an index related to the difference between the bending angles θ1 and θ2 as shown in the following formula (1).

[0033]

[0034] In the above formula (1), Δθ is the above-mentioned bending angle difference [%], θ1 is the bending angle of the warp [°], θ2 is the bending angle of the weft [°], and θave is the average value of the bending angles θ1 and θ2 (θave = (θ1 + θ2) / 2). According to the above formula (1), the bending angle difference Δθ represents the ratio of the difference (absolute value) between the bending angles θ1 and θ2 to the average value θave.

[0035] It should be noted that, θ1 in the above formula (1) may be the bending angle [°] of the warp yarn at one intersection of the mesh fabric, but may also be the average value of the bending angles [°] of the warp yarn at two or more intersections, or may also be the average value of the bending angles [°] of the warp yarn at all intersections. Similarly, θ2 in the above formula (1) may be the bending angle [°] of the weft yarn at one intersection of the mesh fabric, but may also be the average value of the bending angles [°] of the weft yarn at two or more intersections, or may also be the average value of the bending angles [°] of the weft yarn at all intersections.

[0036] In the present embodiment, the bending angles θ1 and θ2 are different from each other, and on this premise, the bending angle difference Δθ is set to 20[%] or less. That is, in the present embodiment, the bending angle difference Δθ exceeds 0[%] and is set to 20[%]. Here, regardless of the magnitude relationship between the bending angles θ1 and θ2, the bending angle θ1 may be larger than the bending angle θ2, or the bending angle θ1 may be smaller than the bending angle θ2. By setting the bending angle difference Δθ to 20[%] or less, it can be seen from the embodiments described later that when an external load acts on the mesh fabric, the mesh fabric can be deformed isotropically. Isotropic deformation refers to deformation that is uniform in all directions within a two-dimensional plane including the warp and weft directions.

[0037] If the mesh fabric is deformed isotropically, it is possible to suppress the stress from being concentrated on a part of the mesh fabric due to an external load. For example, when the mesh fabric is used as a reinforcing material for an ion exchange membrane, when an external load acts on the ion exchange membrane, the stress acting on the ion exchange membrane can be dispersed, thereby suppressing the stress from being concentrated on a part of the ion exchange membrane. Thus, it is possible to suppress damage to the ion exchange membrane caused by stress concentration.

[0038] In order to make the bending angle difference Δθ less than 20[%], the bending angles θ1 and θ2 can be controlled in a manner that satisfies this condition. Here, when manufacturing the mesh fabric, the bending angles θ1 and θ2 can be controlled by adjusting the tension of the warp yarns and the crossing timing (the angle at which the healds being driven are in a closed state in the loom), and the bending angle difference Δθ can be made less than 20[%] regardless of the position of the mesh fabric.

[0039] In the present embodiment, the bending angle difference Δθ may be 20[%] or less, but from the viewpoint of deforming the mesh fabric more isotropically, it is preferably 17[%] or less, and more preferably 10[%] or less. It should be noted that the lower limit of the bending angle difference Δθ may be 0[%] or more, but is preferably 1[%] or more.

[0040] In the present embodiment, if the bending angle difference Δθ is 20[%] or less, the range of the bending angle θ1 of the warp, the bending angle θ2 of the weft, and the absolute value of the difference therebetween (hereinafter also referred to as "absolute value |θ1-θ2|") is not particularly limited. On the other hand, from the viewpoint of deforming the mesh fabric more isotropically, the bending angle θ1 of the warp is preferably 120[°] or more and 190[°] or less, and more preferably 130[°] or more and 180[°] or less. In addition, from the viewpoint of deforming the mesh fabric more isotropically, the bending angle θ2 of the weft is also preferably 120[°] or more and 190[°] or less, and more preferably 130[°] or more and 180[°] or less. In addition, from the viewpoint of deforming the mesh fabric more isotropically, the absolute value |θ1-θ2| is preferably greater than 0[°] and less than 30[°], and more preferably greater than 0[°] and less than 27[°].

[0041] The diameters of the warp and weft may be approximately equal within a range including manufacturing errors, or may be different. It should be noted that if the diameters of the warp and weft are approximately equal, it is easier to deform the mesh fabric isotropically than if the diameters of the warp and weft are different.

[0042] The diameters of the warp and weft are not particularly limited, but are preferably 200 μm or less. By setting the diameters of the warp and weft to 200 μm or less, the proportion of the volume of the yarn in the overall volume of the mesh fabric (including the openings) can be reduced. In other words, the proportion of the volume of the openings in the overall volume of the mesh fabric (including the openings) can be increased.

[0043] Thus, when the mesh fabric is used as a reinforcing material for the ion exchange membrane, it is easy to maintain proton conduction through the opening. Considering this point, the smaller the diameter of the warp and weft, the better, more preferably 100 μm or less, further preferably 80 μm or less, and particularly preferably 60 μm or less. On the other hand, if the diameter of the warp and weft is too small, the mechanical strength of the mesh fabric (thread) is easily reduced, so the diameter of the warp and weft is preferably 10 μm or more.

[0044] The number of meshes of the mesh fabric is not particularly limited and can be appropriately determined according to the purpose of the mesh fabric.

[0045] The opening of the mesh fabric can be 30 μm or more. The opening refers to the distance between two warp yarns adjacent in the weft direction and the distance between two weft yarns adjacent in the warp direction in the mesh fabric, and is the length of one side of the opening formed in the mesh fabric. The opening can be calculated by the following formula (2).

[0046]

[0047] In the above formula (2), OP is the opening [μm], M is the number of meshes [threads / inch], and D is the diameter of the warp and weft [μm]. The number of meshes M is the number of threads contained in a width of 1 inch (2.54 cm) of the mesh fabric. As shown in the above formula (2), the opening OP can be calculated from the number of meshes M and the diameter D of the thread.

[0048] By setting the opening to be 30 μm or more, the opening of the mesh fabric can be increased. Therefore, when the mesh fabric is used as a reinforcing material for an ion exchange membrane, it is easy to maintain proton conduction through the opening. In view of this, the larger the opening, the more preferred, more preferably 40 μm or more, and further preferably 50 μm or more. On the other hand, if the opening is too large, the mesh fabric is difficult to function as a reinforcing material for an ion exchange membrane, so the opening is preferably 200 μm or less.

[0049] The opening area of ​​the mesh fabric is preferably 30% or more. The opening area is an index representing the area ratio of the openings of the mesh fabric, and is calculated by the following formula (3).

[0050]

[0051] In the above formula (3), OPA is the opening area [%], OP is the opening [μm], and D is the diameter of the warp and weft [μm].

[0052] By setting the opening area to 30% or more, the area ratio of the opening of the mesh fabric can be increased. Therefore, when the mesh fabric is used as a reinforcing material for an ion exchange membrane, it is easy to maintain proton conduction through the opening. In view of this, the larger the opening area, the more preferred, more preferably 40% or more. On the other hand, if the opening area is too large, it is difficult for the mesh fabric to function as a reinforcing material for an ion exchange membrane, so the opening area is preferably 90% or less.

[0053] The weave of the mesh fabric is not particularly limited, and for example, a plain weave or a twill weave may be used. When the thickness (yarn thickness) of the mesh fabric is required to be reduced, it is preferred to use a plain weave as the weave.

[0054] The warp and weft yarns are preferably monofilaments. When monofilaments are used, the width of the yarn (the actual diameter of the yarn) can be reduced compared to the case of using multifilaments, so it is easy to enlarge the opening of the mesh fabric as described above.

[0055] In addition, multifilaments are mostly formed by twisting a plurality of monofilaments, so the shape of the multifilaments is easily deviated depending on the position in the length direction of the filaments. On the other hand, monofilaments are not easy to have the shape deviation of the above-mentioned multifilaments. Therefore, by using monofilaments as warp and weft, it is easy to suppress the deviation of the opening in the whole mesh fabric. If the deviation of the opening is suppressed, it is easy to make the mesh fabric deform more isotropically.

[0056] The material of the warp and weft is not particularly limited, and preferably a synthetic fiber with flexibility. As the material of the synthetic fiber, for example, polyethylene terephthalate, polypropylene, 6-nylon, 66-nylon, polyethylene (PE), ethylene-vinyl acetate copolymer, polycarbonate, polyphenylene sulfide (PPS), polyethylene naphthalate, polyetheretherketone (PEEK), modified polyphenylene ether (PPE), polyaryletherketone (PAEK), polystyrene (PS) including crystalline polystyrenes such as syndiotactic polystyrene (SPS) and isotactic polystyrene, and polyimide (PI) can be used. In addition, as the material of the synthetic fiber, aromatic polyamide, polyarylate, ultra-high molecular weight polyethylene, polyparaphenylene benzobisoxazole (PBO), polyparaphenylene benzobithiazole (PBT), polyparaphenylene benzobisimidazole (PBI), polyacetal resin, polyarylate resin, polysulfone resin, polyvinylidene fluoride resin, ethylene tetrafluoroethylene (ETFE), polytetrafluoroethylene (PTFE) and other thermoplastic resins, polylactic acid resin, polyhydroxybutyrate resin, modified starch resin, polycaprolactone resin, polybutadiene The elastomers such as the biodegradable resins such as butylene adipate resin, polybutylene terephthalate resin, polybutylene succinate terephthalate resin, polyethylene succinate resin, phenolic resin, urea resin, melamine resin, unsaturated polyester resin, diallyl phthalate resin, epoxy resin, epoxy acrylate resin, silicone resin, acrylic polyurethane resin, polyurethane resin, silicone resin, polystyrene elastomer, polyethylene elastomer, polypropylene elastomer, polyurethane elastomer. And then, as warp and weft, the fiber generated by natural resins such as fluorine fiber, carbon fiber, liquid crystal polymer (LCP) fiber, lacquer, etc. can be used.

[0057] It is also possible to use more than two of the above materials to form warp and weft. Specifically, a silk with a core-sheath structure can be used so that the material of the core is different from that of the sheath. In addition, different materials can be used for the warp and weft, respectively. When making the silk of the mesh fabric heat-resistant and solvent-resistant, it is preferred to use silk of synthetic fibers, as the synthetic fibers, PE fibers, PTFE fibers, PPS fibers, LCP fibers, PAEK fibers, SPS fibers or PEEK fibers can be used, more preferably PE fibers, PTFE fibers, PPS fibers, LCP fibers or PEEK fibers.

[0058] If a tensile test is performed on a mesh fabric, a curve showing the relationship between the tensile load [N] and the tensile elongation ratio [%] is obtained (hereinafter referred to as a "tensile load-tensile elongation ratio curve"). In the tensile test of the mesh fabric, the more the tensile load increases, the higher the tensile elongation ratio increases, and when the tensile load reaches the limit value (tensile strength), the filaments of the mesh fabric break. In addition, the tensile elongation ratio when the filaments of the mesh fabric break is referred to as the tensile elongation (elongation at break). If a tensile test is performed on the warp direction, a tensile load-tensile elongation ratio curve on the warp direction is obtained, and if a tensile test is performed on the weft direction, a tensile load-tensile elongation ratio curve on the weft direction is obtained. The tensile test is performed in accordance with the provisions of JIS L1096 (Method A (JIS Method)).

[0059] If we focus on the slope [N / %] of the tensile load-tensile elongation ratio curve, we can find the index "slope difference" which is the difference between the slope associated with the warp and the slope associated with the weft as shown in the following formula (4). The slope of the tensile load-tensile elongation ratio curve is the slope in the elastic deformation region of the tensile load-tensile elongation ratio curve.

[0060]

[0061] In the above formula (4), ΔSL is the above-mentioned slope difference [%], SL1 is the slope related to the warp [N / %], SL2 is the slope related to the weft [N / %], and SLave is the average value of the slopes SL1 and SL2 (SLave = (SL1 + SL2) / 2). According to the above formula (4), the slope difference ΔSL represents the ratio of the difference (absolute value) between the slopes SL1 and SL2 to the average value SLave.

[0062] The slope difference ΔSL is preferably 62% or less (i.e., 0% or more and 62% or less). If the slope difference ΔSL is greater than 62%, the anisotropy of the deformation of the mesh fabric tends to become stronger. Therefore, in order to make the mesh fabric deform isotropically, the slope difference ΔSL is preferably set to 62% or less. From the viewpoint of making the mesh fabric deform more isotropically, the slope difference ΔSL is preferably 55% or less (i.e., 0% or more and 55% or less).

[0063] When a mesh fabric is subjected to a tensile test, the tensile strength in the warp direction and the tensile strength in the weft direction are obtained. Furthermore, as shown in the following formula (5), the "tensile strength difference" which is an index related to the difference between the tensile strength in the warp direction and the tensile strength in the weft direction can be obtained.

[0064]

[0065] In the above formula (5), ΔS is the above-mentioned tensile strength difference [%], S1 is the tensile strength related to the warp [N], S2 is the tensile strength related to the weft [N], and Save is the average value of the tensile strengths S1 and S2 (Save = (S1 + S2) / 2). According to the above formula (5), the tensile strength difference ΔS represents the ratio of the difference (absolute value) between the tensile strengths S1 and S2 to the average value Save.

[0066] The tensile strength difference ΔS is preferably 20% or less (i.e., 0% or more and 20% or less). If the tensile strength difference ΔS is higher than 20%, the anisotropy of the deformation of the mesh fabric tends to become stronger. Therefore, in order to make the mesh fabric deform isotropically, the tensile strength difference ΔS is preferably set to 20% or less. From the viewpoint of making the mesh fabric deform more isotropically, the tensile strength ΔS is more preferably 18% or less (i.e., 0% or more and 18% or less).

[0067] When the mesh fabric is subjected to a tensile test, the tensile elongation in the warp direction and the tensile elongation in the weft direction are obtained. Then, as shown in the following formula (6), the "tensile elongation difference" which is an index of the difference between the tensile elongation in the warp direction and the tensile elongation in the weft direction can be obtained.

[0068]

[0069] In the above formula (6), ΔL is the above-mentioned tensile elongation difference [%], L1 is the tensile elongation related to the warp [%], L2 is the tensile elongation related to the weft [%], and Lave is the average value of the tensile elongations L1 and L2 (Lave = (L1 + L2) / 2). According to the above formula (6), the tensile elongation difference ΔL represents the ratio of the difference (absolute value) between the tensile elongations L1 and L2 to the average value Lave.

[0070] The tensile elongation difference ΔL is preferably 68% or less (i.e., 0% or more and 68% or less). If the tensile elongation difference ΔL is higher than 68%, the anisotropy of the deformation of the mesh fabric tends to become stronger. Therefore, in order to deform the mesh fabric isotropically, the tensile elongation difference ΔL is preferably set to 68% or less. From the viewpoint of deforming the mesh fabric more isotropically, the tensile elongation difference ΔL is more preferably 55% or less (i.e., 0% or more and 55% or less).

[0071] The mesh fabric only needs to satisfy at least one of the following conditions: the slope difference ΔSL is 62% or less, the tensile strength difference ΔS is 20% or less, and the tensile elongation difference ΔL is 68% or less. That is, only one of the slope difference ΔSL, the tensile strength difference ΔS, and the tensile elongation difference ΔL may be considered, or a combination of any two of the slope difference ΔSL, the tensile strength difference ΔS, and the tensile elongation difference ΔL may be considered, or all of the slope difference ΔSL, the tensile strength difference ΔS, and the tensile elongation difference ΔL may be considered.

[0072] For mesh fabrics, the thermal deformation in the warp and weft directions can be measured by using a thermomechanical analyzer (TMA). Furthermore, as shown in the following formula (7), the "thermal deformation difference" which is an index related to the difference between the thermal deformation in the warp direction and the thermal deformation in the weft direction can be obtained.

[0073]

[0074] In the above formula (7), ΔD is the above-mentioned difference in thermal deformation [%], D1 is the thermal deformation in the warp direction [mm], and D2 is the thermal deformation in the weft direction [mm]. The thermal deformations D1 and D2 become negative values ​​when the mesh fabric shrinks in the warp direction and the weft direction, respectively, and become positive values ​​when the mesh fabric stretches in the warp direction and the weft direction. Dave is the average value of the thermal deformations D1 and D2 (Dave = (D1 + D2) / 2). According to the above formula (7), the thermal deformation difference ΔD represents the ratio of the difference (absolute value) between the thermal deformations D1 and D2 to the absolute value of the average value Dave.

[0075] The difference in thermal deformation ΔD is preferably 180% or less (i.e., 0% or more and 180% or less). When the difference in thermal deformation ΔD is higher than 180%, the anisotropy of the deformation of the mesh fabric tends to become stronger. Therefore, in order to deform the mesh fabric isotropically, the difference in thermal deformation ΔD is preferably 180% or less. From the viewpoint of deforming the mesh fabric more isotropically, the difference in thermal deformation ΔD is more preferably 160% or less (i.e., 0% or more and 160% or less).

[0076] The mesh fabric of the present invention described above is suitable for use in various solvents and high temperature environments. For example, it can be used as a support for membranes such as artificial skin, ion exchange resins such as chlorine-resistant reverse osmosis membranes, various structural materials, electrochemical uses, humidification membranes, antifogging membranes, antistatic membranes, deoxidation membranes, solar cell membranes, gas barrier membranes, etc. It is particularly preferably used for electrochemical uses such as electrolyte membranes and diaphragm supports used in solid polymer fuel cells, redox flow batteries, electrochemical hydrogen pumps, water electrolysis devices, alkaline water electrolysis, solid polymer electrolyte membrane-type hydrogen manufacturing devices, chlor-alkali electrolysis devices, etc.

[0077] Example 1

[0078] The mesh fabric was produced using a rapier loom. PPS monofilaments with a yarn diameter of 56 [μm] were used as warp and weft yarns constituting the mesh fabric, and the number of meshes was 150 [threads / inch].

[0079] (Example 1)

[0080] The tension per warp yarn was set to 15 to 20 [cN] and the crossing timing was set to 320 [°], thereby producing a mesh fabric as Example 1.

[0081] (Example 2)

[0082] The tension per warp yarn was set to 15 to 20 [cN] and the crossing timing was set to 330 [°], thereby producing a mesh fabric as Example 2.

[0083] (Example 3)

[0084] The tension per warp yarn was set to 20 to 25 [cN] and the crossing timing was set to 320 [°], thereby producing a mesh fabric as Example 3.

[0085] (Example 4)

[0086] The tension per warp yarn was set to 20 to 25 [cN] and the crossing timing was set to 330 [°], thereby producing a mesh fabric as Example 4.

[0087] (Comparative Example)

[0088] The tension per warp yarn was set to 25 to 30 [cN] and the crossing timing was set to 340 [°] to produce a mesh fabric as a comparative example.

[0089] (Example 5)

[0090] As the warp and weft yarns constituting the mesh fabric, PE monofilaments with a yarn diameter of 70 [μm] were used, and the number of meshes was 70 [threads / inch]. In addition, the tension of each warp yarn was set to 20 to 25 [cN], and the crossing timing was set to 320 [°]. The other conditions were the same as those in Example 1, thereby manufacturing a mesh fabric as Example 5.

[0091] (Example 6)

[0092] As the warp and weft yarns constituting the mesh fabric, LCP monofilaments with a yarn diameter of 24 [μm] were used, and the number of meshes was 150 [threads / inch]. In addition, the tension of each warp yarn was set to 5 to 10 [cN], and the crossing timing was set to 320 [°]. The other conditions were the same as those in Example 1, thereby manufacturing a mesh fabric as Example 6.

[0093] (Example 7)

[0094] As the warp and weft yarns constituting the mesh fabric, PEEK monofilaments with a yarn diameter of 50 [μm] were used, and the number of meshes was 150 [threads / inch]. In addition, the tension of each warp yarn was set to 20 to 25 [cN], and the crossing timing was set to 320 [°]. The other conditions were implemented in the same manner as in Example 1, thereby manufacturing a mesh fabric as Example 7.

[0095] (Example 8)

[0096] As the warp and weft yarns constituting the mesh fabric, PTFE monofilaments with a yarn diameter of 60 [μm] were used, and the number of meshes was 80 [threads / inch]. In addition, the tension of each warp yarn was set to 20 to 25 [cN], and the crossing timing was set to 320 [°]. The other conditions were implemented in the same manner as in Example 1, thereby manufacturing a mesh fabric as Example 8.

[0097] (Measurement of bending angle)

[0098] The mesh fabrics of Examples 1 to 8 and the comparative example were cut at predetermined positions (positions at which the bending angles θ1 and θ2 were measured, respectively), and the cut surfaces were observed using an optical microscope, thereby measuring the bending angle θ1 of the warp and the bending angle θ2 of the weft, respectively. In addition, the bending angle difference Δθ was calculated based on the above formula (1). It should be noted that the bending angle θ1 of the warp and the bending angle θ2 of the weft were the average values ​​of the bending angles [°] at 6 intersections randomly selected from the intersections of the mesh fabric.

[0099] (Determination of tensile strength and tensile elongation)

[0100] Mesh sheets (30 [mm] × 10 [mm]) of the same size in the warp and weft directions were cut out from the mesh fabrics of Examples 1 to 8 and Comparative Examples, and a tensile test was performed using a tensile testing machine. The distance between samples was set to 10 [mm], and the tensile speed was set to 10 [mm / min]. A tensile force in the warp direction was applied to the mesh sheet, and the tensile strength S1 and tensile elongation L1 when the mesh sheet broke were measured. In addition, a tensile force in the weft direction was applied to the mesh sheet, and the tensile strength S2 and tensile elongation L2 when the mesh sheet broke were measured.

[0101] After measuring the tensile strengths S1 and S2, the tensile strength difference ΔS[%] is calculated based on the above formula (5). In addition, after measuring the tensile elongations L1 and L2, the tensile elongation difference ΔL[%] is calculated based on the above formula (6). On the other hand, through the above-mentioned tensile test, tensile strength-tensile elongation curves are obtained for the warp and weft directions, respectively, and the slopes SL1 and SL2 of the elastic deformation area (straight line portion at the initial stage of stretching) are calculated as the slopes of the tensile strength-tensile elongation curves. In addition, after measuring the slopes SL1 and SL2, the slope difference ΔSL is calculated based on the above formula (4).

[0102] (Measurement of thermal deformation)

[0103] A mesh sheet (15 [mm] × 5 [mm]) of the same size in the warp and weft directions was cut out from the mesh fabrics of Examples 1 to 8 and the comparative example, and the thermal deformation of the mesh sheet (the distance between the chucks was 10 [mm]) was measured using a thermomechanical analysis device. Specifically, for the mesh sheet, the thermal deformation in the warp direction and the thermal deformation in the weft direction were measured. As the measurement conditions, the temperature was raised from 30 [°C] to 250 [°C] under the atmosphere with a tensile load of 50 mN / 5 mm and a heating rate of 10 [°C / min]. Then, the thermal deformation was measured at a temperature of 125 [°C].

[0104] The above measurement results are shown in Table 1 below.

[0105] [Table 1]

[0106]

[0107] According to Examples 1 to 8, by setting the bending angle difference Δθ to 20% or less, the tensile strength difference ΔS, the tensile elongation difference ΔL, the slope difference ΔSL, and the thermal deformation difference ΔD can all be reduced compared to the comparative example in which the bending angle difference Δθ is set to be higher than 20%. Regarding the tensile strength difference ΔS, the tensile elongation difference ΔL, and the slope difference ΔSL, it can be seen that Examples 1 to 8 are lower than the comparative example, and therefore are easily deformed isotropically to an external load (external force). In addition, regarding the thermal deformation difference ΔD, it can be seen that Examples 1 to 8 are lower than the comparative example, and therefore are easily deformed isotropically to an external load (heat).

[0108] It should be noted that, as can be understood from the above-mentioned Examples 1 to 8 and Comparative Examples, the bending angle difference can be further reduced by further reducing the warp tension and the crossing timing. However, if the warp tension and the crossing timing are too small, the weaving property will be impaired, so it is necessary to adjust the warp tension and the crossing timing within a range that does not impair the weaving property.

[0109] Description of Reference Numerals

[0110] 1: warp, 2a, 2b, 2c: weft, P1, P2, P3: reference points, L1, L2: straight lines.

Claims

1. A mesh fabric, characterized in that: It is a mesh fabric containing warp and weft threads. The bending angles of the warp and weft threads at the intersections of the warp and weft threads are different from each other. The ratio of the absolute value of the difference between the bending angles of the warp and the weft to the average value of the bending angles of the warp and the weft is 20% or less.

2. The mesh fabric according to claim 1, characterized in that: It meets at least one of the following conditions: The ratio of the absolute value of the difference between the tensile strength in the warp direction and the tensile strength in the weft direction to the average value of the tensile strength in the warp direction and the weft direction is 20% or less; The ratio of the absolute value of the difference between the tensile elongation in the warp direction and the tensile elongation in the weft direction to the average value of the tensile elongation in the warp direction and the weft direction is 68% or less; as well as Regarding the slope in the elastic deformation region of the curve representing the relationship between the tensile load and the tensile elongation ratio, the ratio of the absolute value of the difference between the warp and weft slopes to the average value of the warp and weft slopes is 62% or less.

3. The mesh fabric according to claim 1 or 2, characterized in that: The ratio of the absolute value of the difference between the thermal deformation amount in the warp direction and the thermal deformation amount in the weft direction to the average value of the thermal deformation amount in the warp direction and the weft direction is 180% or less.

4. The mesh fabric according to claim 1, characterized in that: At least one of the warp yarn and the weft yarn is a synthetic fiber.

5. The mesh fabric according to claim 4, characterized in that: The synthetic fiber is PE fiber, PTFE fiber, PPS fiber, LCP fiber or PEEK fiber.

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