Fabric

Abstract

In order to provide a fabric having excellent low-friction properties and sliding durability and capable of suppressing frictional electrification when subjected to sliding against an insulator, the fabric according to the present invention includes a fabric base material composed of fluororesin fibers and non-fluororesin fibers. Conductive particles are attached to both the fluororesin fibers and the non-fluororesin fibers. This fabric is to be integrated with a surface of a base material for a composite member to form the composite member. The composite member is suitable for use in sliding contact with a material made of an insulator.

Description

fabric

[0001] The present invention relates to fabrics.

[0002] A known technology utilizes the low coefficient of friction of fluororesin to impart low friction and sliding durability to the sliding interface by interposing a sliding fabric made of fluororesin fiber between the sliding points of mechanical parts. Conventionally, the mainstream method was to interpose a sliding fabric between metal mechanical parts, but in recent years, with the advancement of multi-material components, it is anticipated that sliding fabrics will be used in systems where one of the sliding members is made of an insulating material such as resin, pulp, or natural fiber, and there is a demand for sliding fabrics that are suitable for such usage.

[0003] As a technology for improving the basic performance of sliding fabrics, such as low friction and sliding durability, a technology related to a fabric combining fluororesin fibers with fibers stronger than the fluororesin fibers is known. For example, Patent Document 1 discloses that by forming a multi-layer fabric consisting of a sliding fabric containing fluororesin fibers and a base fabric containing fibers other than the fluororesin fibers, the base fabric firmly binds the PTFE fibers of the sliding fabric and accumulates the PTFE fibers within the multi-layer fabric, thereby achieving long-term sliding properties. Furthermore, it discloses that by selecting PPS fibers as the fibers constituting the base fabric, durability can be obtained even in harsh environments, such as heat resistance, chemical resistance, and hydrolysis resistance.

[0004] On the other hand, known techniques for imparting antistatic properties to fabrics include a method of hydrophilizing the fiber surface using plasma processing or a hydrophilic agent (e.g., Patent Document 2) and a method of combining conductive fibers (e.g., Patent Document 3).

[0005] Japanese Patent No. 6398189 Japanese Patent Laid-Open No. 2007-169865 International Publication No. 02 / 075030

[0006] Fluorine resin has high insulating properties and is on the most negative side of the triboelectric series, so it is prone to becoming negatively charged when it comes into contact with other materials. Therefore, when a sliding fabric slides over an insulator, the fluororesin fibers of the sliding fabric become negatively charged, which raises concerns about sparks and dielectric breakdown of the sliding fabric.

[0007] According to the studies of the present inventors, it was found that a fabric in which a fluororesin fiber is composited with a PPS fiber, as described in Patent Document 1, becomes more strongly charged when sliding against an insulator than a fabric made of 100% fluororesin fiber. This is thought to be because, in addition to charging between the insulator and the fluororesin fiber, charging occurs due to the friction between the fluororesin fiber and the PPS fiber. As such, it is difficult with conventional technology to achieve both the suppression of spark generation and dielectric breakdown and sliding durability, and it was considered necessary to develop a technology to impart antistatic properties to sliding fabrics.

[0008] However, fluororesin fibers are extremely hydrophobic, making it difficult to significantly hydrophilize the fiber surface by applying the technology described in Patent Document 2. Therefore, the inventors investigated interweaving conductive fibers into a fabric made of fluororesin fibers by applying the technology described in Patent Document 3, but were unable to obtain a sufficient effect of suppressing triboelectric charging. While it might be possible to achieve the desired effect of suppressing charging by increasing the proportion of conductive fibers, this would impose limitations on fabric design, and there were concerns that sliding performance might be reduced.

[0009] Therefore, an object of the present invention is to provide a fabric that has low friction and excellent sliding durability, and is capable of suppressing frictional electrification when subjected to sliding contact with an insulator.

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

[0011] (1) A fabric comprising a fabric substrate made of fluororesin fibers and fibers other than fluororesin fibers, with conductive particles attached to both the fluororesin fibers and the fibers other than fluororesin fibers.

[0012] (2) The fabric according to (1) above, wherein the conductive particles are attached to the fluororesin fibers and fibers other than the fluororesin fibers via a binder resin.

[0013] (3) The fabric according to (1) or (2), wherein the mass ratio of the binder resin to the fabric substrate is 0.01% or more and 30% or less.

[0014] (4) The amount of the conductive particles attached to the fabric per unit volume is 3000 g / m ３ More than 50000g / m３ The fabric according to any one of (1) to (3), which is as follows:

[0015] (5) The fabric according to any one of (1) to (4), wherein the conductive particles are adhered to the entire surface of the fabric in the thickness direction.

[0016] (6) The fabric according to any one of (1) to (5), wherein the fabric substrate has a double structure.

[0017] (7) The fabric according to any one of (1) to (6), wherein the area ratio of the fluororesin fibers on one surface of the fabric is lower than the area ratio of the fluororesin fibers on the other surface.

[0018] (8) A fabric according to any one of (1) to (7), which contains a thermosetting resin inside the surface layer on one side of the fabric, and the thermosetting resin is not exposed on the other side.

[0019] (9) The fabric according to any one of (1) to (8), which is integrated with the surface of a substrate for a composite material to form a composite material, and the composite material is used to slide against a material made of an insulating material.

[0020] According to the present invention, there is provided a fabric that has low friction and excellent sliding durability, and is capable of suppressing frictional electrification when subjected to sliding contact with an insulator.

[0021] The fabric according to the present invention includes a fabric substrate made of fluororesin fibers and fibers other than fluororesin fibers, and conductive particles are attached to both the fluororesin fibers and the fibers other than fluororesin fibers. If conductive particles are attached to only one of the fluororesin fibers or the fibers other than fluororesin fibers, one of the fibers will be insulated, and frictional electrification between the fluororesin fibers and the fibers other than fluororesin fibers will not be sufficiently suppressed, resulting in the desired antistatic properties. In a fabric made of fluororesin fibers and fibers other than fluororesin fibers, the fluororesin fibers transfer to the fibers other than fluororesin fibers with sliding, forming a self-lubricating film and exhibiting low friction and sliding durability. Therefore, by attaching a conductive resin to the fluororesin fibers, conductive particles are kneaded into the self-lubricating film, exhibiting excellent antistatic properties.

[0022] It is preferable that the conductive particles are distributed throughout the entire thickness of the fabric, since this allows for continuous conductivity even when the fabric is slid. Even if the outermost surface fibers are worn away with sliding, the conductive particles are continuously supplied, so antistatic properties are maintained. In the above, "distributed throughout the thickness of the fabric" means that the conductive particles are not only present on the outermost surface of the fabric, but also adhere to the inner layer region in the thickness direction of the fabric.

[0023] The fabric of the present invention has excellent low friction and sliding properties due to the fluororesin fibers being exposed on at least one surface, making it suitable for use as a sliding fabric with the surface serving as the sliding surface. Therefore, the presence of conductive particles on at least the surface suitable for use as the sliding surface (e.g., the surface with the greater amount of exposed fluororesin fibers, or one or both surfaces if the exposure is the same) (hereinafter, the surface suitable for use as the sliding surface may be referred to as the "sliding surface" for convenience) provides sufficient antistatic properties at the initial stage of sliding and suppresses sparks due to frictional charging. Therefore, it is preferable that at least the conductive particles be present on the sliding surface side. Furthermore, the presence of conductive particles extending deeper in the thickness direction from the sliding surface ensures that conductive particles are continuously supplied even when the outermost surface fibers wear away, and thus the presence of conductive particles deeper, and ultimately throughout the entire thickness direction, maintains antistatic properties for a longer period of time.

[0024] Possible methods for attaching conductive particles to a fabric substrate include impregnating and coating the fabric substrate with a slurry containing dispersed conductive particles, and then heating the fabric substrate to a temperature near the melting point of the fluororesin fibers and fibers other than the fluororesin fibers to fuse the conductive particles to each of the fluororesin fibers and fibers other than the fluororesin fibers. Alternatively, the fabric may be impregnated with a binder resin containing conductive particles, and the conductive particles may be attached to the fluororesin fibers and fibers other than the fluororesin fibers via the binder resin. When a fabric substrate made of fluororesin fibers and fibers other than the fluororesin fibers is heated to a temperature above the melting point of the fibers to fuse the conductive particles, problems may arise due to the difference in melting point between the fluororesin fibers and fibers other than the fluororesin fibers. That is, when the fabric substrate is heat-treated at a temperature above the melting point of either fiber, the fiber with the lower melting point may melt excessively, potentially impairing the strength and tribological properties of the fabric. If the heat treatment is performed at a temperature lower than the melting point of one fiber and equal to or higher than the melting point of the other fiber, the conductive particles will not adhere sufficiently to the fiber with the lower melting point, making it difficult to obtain the desired antistatic properties. From the above viewpoints, it is preferable that the conductive particles adhere to the fiber via the binder resin.

[0025] When conductive particles are attached to fibers via a binder resin, the effect can be further improved by selecting the mass ratio of the fabric to the resin. Here, the mass ratio of the fabric to the binder resin is the value obtained by dividing the mass of the binder resin per unit area by the mass of the fabric substrate per unit area. The mass of the binder resin here refers to the mass of the binder resin excluding conductive particles. By impregnating the fabric with a binder resin containing dispersed conductive particles so as to adequately fill the voids in the fabric, it is possible to effectively form a self-lubricating film (described below), resulting in excellent low friction and sliding durability. Specifically, by setting the mass ratio of the resin to the fabric relatively small, such as in a form in which the conductive particles are attached to the fibers with a small amount of binder resin, the conductive particles can be stably attached to each fiber while effectively forming a self-lubricating film that develops with wear, thereby fully demonstrating the low friction and sliding durability inherent in the fluororesin fiber. To obtain the above-mentioned configuration, a treatment liquid containing conductive particles and a binder resin is used, and the viscosity is adjusted to a level that allows the above-mentioned configuration to be obtained. For example, when using a treatment liquid of a binder resin in which conductive particles are dispersed, it is effective to adjust the viscosity by, for example, diluting it with a solvent as necessary to reduce the viscosity, and then treating it by the method described below. This prevents excess binder resin from adhering, allows the conductive particles to be uniformly distributed in the thickness direction of the fabric, and allows the conductive particles to be present between the fibers, reducing frictional electrification between the yarns.

[0026] In applications where it is desirable for the conductive particles to continuously adhere to the fibers and maintain antistatic properties, it is preferable to increase the mass ratio of the binder resin to a certain extent to obtain a relatively strong adhesive force. On the other hand, when imparting antistatic properties to the fabric of the present invention used in sliding materials, the appropriate adhesive force differs for the following reasons. When the fabric of the present invention is repeatedly subjected to sliding under a pressurized environment, the fluororesin fibers present on the sliding surface are worn away, forming wear powder. At this time, wear powder containing a mixture of fluororesin and conductive particles is formed, which adheres to the mating material and fibers other than the fluororesin fibers under the pressure of the sliding, forming a self-lubricating film. Under a pressurized environment, the pressure promotes adhesion of the wear powder to each fiber, further accelerating the formation of this self-lubricating film. Therefore, even if the fluororesin fibers and conductive particles are once detached, they continue to be mixed and kneaded as wear powder, eventually forming a film, and therefore the antistatic properties are not reduced. Conversely, if the conductive particles and the fluororesin fibers or fibers other than the fluororesin fibers are too firmly bonded to each other, resistance to separating them during sliding occurs, which may result in a shift in the friction coefficient toward a higher value. From the above viewpoints, the mass ratio of the binder resin to the fabric substrate is preferably 30% or less, more preferably 10% or less, and particularly preferably 3% or less. From the viewpoint of imparting a certain level of adhesive force to the fibers constituting the fabric substrate and the conductive particles, the mass ratio of the binder resin to the fabric substrate is preferably 0.01% or more, more preferably 0.05% or more, and particularly preferably 0.1% or more.

[0027] The amount of conductive particles attached to the fabric of the present invention can be selected depending on the required antistatic properties and sliding properties. The amount of conductive particles attached is usually expressed as weight per unit area, but when used as a sliding fabric, the optimal amount varies depending on the thickness of the fabric. That is, with a thick fabric, there is a larger area inside the fabric (parts not exposed on either the front or back) where conductive particles can be attached. The conductive particles attached inside the fabric are gradually exposed to the surface when the surface is worn away by sliding, and can impart antistatic properties, so the range of appropriate conductive particle attachment amounts is wider for thick fabrics. On the other hand, with thin fabrics, there are fewer conductive particles that can be attached inside the fabric, so most of the conductive particles present per unit area are exposed to the surface, and therefore the range of optimal conductive particle attachment amounts for thin fabrics is relatively narrower than for thick fabrics. For the above reasons, the amount of conductive particles attached is determined as the attachment amount per unit volume (g / m), which is calculated by dividing the mass per unit area by the thickness of the fabric. ３ ) is preferably controlled. From the viewpoint of obtaining excellent low friction and sliding durability, it is preferable to reduce the amount of conductive particles attached to the fabric within a range that allows obtaining the desired antistatic properties. When the amount of conductive particles attached to the fabric is large, the amount of conductive particle components in the wear powder generated during sliding increases, and the content ratio of fluororesin fiber components becomes relatively small, which inhibits the formation of a self-lubricating film during sliding under pressure. Therefore, from the above viewpoint, the amount of attachment per unit volume is set to 50,000 g / m ３ Preferably, it is less than 30,000 g / m ３ It is particularly preferable that the amount of conductive particles is 3000 g / m or less. From the viewpoint of not only the initial antistatic performance but also maintaining the performance after sliding, it is preferable that a large amount of conductive particles is present within a range that does not affect low friction and sliding durability. Even when the conductive particles are kneaded into the fluororesin due to plastic deformation caused by sliding, the presence of a certain amount of conductive particles forms a conductive path, making it possible to maintain excellent conductivity and antistatic properties. From the above viewpoint, the amount of adhesion per unit volume is 3000 g / m ３ More preferably, it is 8000 g / m or more. ３ or more, and 12000 g / m ３ More preferably, it is equal to or greater than this.

[0028] The fabric substrate used in the present invention is not particularly limited in terms of textile form, and any form such as woven fabric, knitted fabric, wet-laid nonwoven fabric, dry-laid nonwoven fabric, etc. can be used. However, a woven fabric is preferred in that the constituent fibers are tightly bound to each other and dimensional stability is obtained.

[0029] When selecting a woven fabric structure for the fabric substrate used in the present invention, the weave is not particularly limited, and plain weave, twill weave, satin weave, and variations thereof can be used. Among them, plain weave is particularly preferred because it has a high binding force between the warp and weft yarns and provides better abrasion resistance.

[0030] The structure of the fabric substrate used in the present invention is not particularly limited, and not only a single structure but also a multi-layer structure such as a double structure or a triple structure can be adopted, but a multi-layer structure of two or more layers is preferable. By adopting a multi-layer structure, the conductive particles attached to the layers constituting the inside of the fabric are exposed with sliding, and it is possible to more continuously exhibit antistatic properties.

[0031] In the fabric of the present invention, it is preferable that the area ratio of the fluororesin fiber on one side is lower than that on the other side. Thus, when one side of the fabric of the present invention is bonded to a substrate for a composite material to form a composite material by integrating the two, it is preferable to bond the side with the lower area ratio of the fluororesin fiber as the bonding surface, since this improves adhesion to other materials. Even in the case of a double structure, fibers other than the fluororesin fiber may be present on the side with the higher area ratio of the fluororesin fiber.

[0032] The fluororesin that is a component of the fluororesin fiber that constitutes the fabric substrate used in the present invention may be any fluororesin that is composed of a monomer unit containing one or more fluorine atoms in the main chain or side chain, and among these, a fluororesin that is composed of a monomer unit with a large number of fluorine atoms is preferred.

[0033] The monomer units containing one or more fluorine atoms preferably account for 70 mol % or more, more preferably 90 mol % or more, and even more preferably 95 mol % or more of the repeating structural units of the polymer.

[0034] Examples of the monomer containing one or more fluorine atoms include fluorine atom-containing vinyl monomers such as tetrafluoroethylene, hexafluoropropylene, and chlorotrifluoroethylene, and among these, it is preferable to use at least tetrafluoroethylene.

[0035] As the fluororesin, for example, polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-p-fluoroalkyl vinyl ether copolymer (PFA), polychlorotrifluoroethylene (PCTFE), ethylene-tetrafluoroethylene copolymer (ETFE), etc. can be used alone or in a blend of two or more types.

[0036] In a fluororesin containing tetrafluoroethylene units, a larger content of tetrafluoroethylene units is preferable in terms of sliding properties, and the resin is preferably a homopolymer or copolymer in which 90 mol % or more, preferably 95 mol % or more of the total is tetrafluoroethylene, and it is most preferable to use polytetrafluoroethylene fiber as a tetrafluoroethylene homopolymer.

[0037] The fluororesin fiber constituting the fabric substrate used in the present invention may be in the form of either a monofilament consisting of a single filament or a multifilament consisting of multiple filaments. However, by selecting a multifilament, the surface area of ​​the fiber is increased, allowing the conductive particles to be attached more uniformly.

[0038] The total fineness of the fluororesin fibers constituting the fabric substrate used in the present invention is preferably within the range of 25 to 6000 dtex. It is more preferably within the range of 200 to 5500 dtex, and even more preferably within the range of 400 to 1500 dtex. If the total fineness of the fibers constituting the fabric is 25 dtex or more, the strength of the fibers can be ensured to a certain extent, and thread breakage during weaving can be reduced, improving processability. If it is 6000 dtex or less, good processability during weaving can be obtained.

[0039] From the viewpoint of improving the abrasion resistance of the fabric of the present invention, it is preferable that the fibers other than the fluororesin fibers constituting the fabric substrate used in the present invention have a tensile strength of 2 cN / dtex or more. It is more preferably 5 cN / dtex or more, and particularly preferably 20 cN / dtex or more. This can suppress fiber breakage even when sliding is applied, and can function for a long time as a receptacle for wear powder of the fluororesin fibers and conductive particles detached from the fibers. As a result, it is possible to achieve both long-term sliding durability and antistatic properties. From the viewpoint of weaving, the practical upper limit of the strength of the fibers other than the fluororesin fibers is 100 cN / dtex.

[0040] The fabric of the present invention can be used in a variety of environments, including indoors and outdoors. To achieve long-term sliding durability and antistatic properties even in outdoor environments, it is preferable that the fibers other than the fluororesin fibers not significantly decrease in strength even when exposed to ultraviolet rays and function for a long time as a receptacle for wear powder of the fluororesin fibers and conductive particles detached from the fibers during sliding. Therefore, it is preferable that the fibers other than the fluororesin fibers that make up the fabric substrate used in the present invention have excellent weather resistance.

[0041] From the viewpoint of durability in an environment where frictional heat is generated by sliding, it is preferable that the fibers other than the fluororesin fibers constituting the fabric substrate used in the present invention are heat-resistant fibers. The frictional heat generated by sliding can reach 200°C to 250°C depending on the conditions. If fibers with melting points in this temperature range are present, the molten fibers will coat the fabric surface and the conductive particles. This temporarily weakens the sliding, and even when cooled, the molten resin tends to inhibit the exposure of the conductive particles.

[0042] From the above viewpoints, the fibers other than the fluororesin fibers constituting the fabric of the present invention can be organic fibers such as cotton, polyester fibers, polyamide fibers, polyparaphenylene terephthalamide (para-aramid) fibers, polymetaphenylene isophthalamide (meta-aramid) fibers, polyphenylene sulfide (PPS) fibers, polyparaphenylene benzobisoxazole (PBO) fibers, ultrahigh molecular weight polyethylene (UHMWPE) fibers, and liquid crystal polyester fibers, or inorganic fibers such as glass fibers, carbon fibers, and silicon carbide fibers. From the viewpoint of processability, organic fibers are preferred, and from the viewpoint of heat resistance, cotton, polyparaphenylene terephthalamide (para-aramid) fibers, polymetaphenylene isophthalamide (meta-aramid) fibers, polyphenylene sulfide (PPS) fibers, polyparaphenylene benzobisoxazole (PBO) fibers, and liquid crystal polyester fibers are more preferred. Furthermore, from the viewpoint of weather resistance, polyphenylene sulfide (PPS) fibers can be cited as a particularly preferred fiber. In conventional technology, when polyphenylene sulfide (PPS) fibers were used, they were prone to frictional charging, but by using the configuration of the present invention, it is possible to obtain a fabric that combines sliding properties, heat resistance, weather resistance, and antistatic properties.

[0043] The form of the fibers other than the fluororesin fibers is not particularly limited, and either a filament (long fiber) or a spun yarn (spun yarn) may be used, but from the viewpoint of the tensile strength and tensile rigidity between the single fibers, a filament is preferred. Furthermore, either a monofilament consisting of one filament or a multifilament consisting of multiple filaments can be used, but a multifilament is particularly preferred because it has a larger surface area than a monofilament having the same fineness as the total fineness of the multifilament, making it easier for wear powder of the fluororesin fibers generated during sliding and conductive particles detached from the fibers to be transferred.

[0044] The total fineness of the fibers other than the fluororesin fibers that make up the fabric substrate used in the present invention is preferably within the range of 50 to 4000 dtex. It is more preferably within the range of 100 to 2000 dtex, and even more preferably within the range of 200 to 1000 dtex. When the total fineness of the fibers that make up the fabric is 50 dtex or more, the strength of the fibers is high, fiber breakage during abrasion can be suppressed, and thread breakage during weaving can be reduced, improving processability. When it is 4000 dtex or less, unevenness on the fabric surface is small, and the impact on low friction can be suppressed.

[0045] The conductive particles constituting the fabric of the present invention are not particularly limited, and include carbon-based particles such as carbon black, graphite, carbon nanotubes, and graphene; metal-based particles such as silver and copper; and ceramic particles such as calcium carbonate and glass beads coated with a conductive layer such as metal plating. However, carbon-based particles are particularly preferred from the viewpoint of suppressing secondary wear of the sliding counterpart material.

[0046] When attaching the conductive particles to the fibers via a binder resin, the binder resin can be selected appropriately, but if a thermosetting resin such as an epoxy resin or a phenolic resin is used, hard particles are generated with sliding, which induces secondary wear and makes it difficult to obtain extremely excellent wear resistance. Therefore, it is preferable to use a thermoplastic resin as the binder resin, and a urethane-based resin is particularly preferable from the viewpoint of adhesion to the fibers.

[0047] In the present invention, when the conductive particles are attached to the fibers via a binder resin, the means for doing so is not particularly limited, but when the binder resin is liquid and processable, for example, when it is liquid itself, or when it is dissolved or dispersed in a solvent, dispersion medium, or the like to form a treatment liquid, coating methods such as spraying, dip-nip (DIP / NIP) coating, knife coating, comma coating, gravure coating, flexographic printing, brush coating, melt extrusion lamination, etc. are preferred. Among these, DIP / NIP coating is preferred from the viewpoint of coating the conductive particles over the entire surface in the thickness direction.

[0048] If necessary, a lubricant or the like can be added to the fabric. The type of lubricant is not particularly limited, but a silicon-based lubricant or a fluorine-based lubricant is preferred.

[0049] One side of the fabric may further be impregnated with a thermosetting resin. Preferably, the thermosetting resin is impregnated so that it is not exposed on the other side. When the fabric of the present invention is used as a sliding fabric, the side impregnated with the thermosetting resin is preferably the side opposite to the side that is suitable for use as a sliding surface. If the thermosetting resin is exposed on the sliding surface, the coefficient of friction of the thermosetting resin becomes dominant on the exposed surface, and the low friction properties of the fluororesin fiber tend to be less fully exhibited. Impregnating one side of the fabric, preferably the side opposite the sliding surface, with the thermosetting resin constrains the inter-yarn gaps, thereby suppressing triboelectric charging due to friction between the fibers constituting the fabric. Furthermore, adequate constraining of the inter-yarn gaps prevents stress concentration at the intersections during sliding, improving sliding durability. On the other hand, if the weight ratio of the thermosetting resin is too high, the interfiber voids will be excessively filled, and the worn fluororesin fibers will adhere to fibers other than the fluororesin fibers, preventing the formation of a self-lubricating film. From this perspective, the mass ratio of the thermosetting resin to the fabric substrate is preferably 30% or less, more preferably 20% or less, and even more preferably 10% or less. By setting the mass ratio to 3% or more, uniform coating on the fabric substrate is facilitated, stress is not concentrated in areas not containing the thermosetting resin, and sliding durability can be effectively maintained.

[0050] As described above, when a fabric is impregnated with a thermosetting resin so that one side is impregnated with the thermosetting resin and the other side is not exposed, methods such as brush coating, knife coating, thermal transfer coating, spray coating, curtain coating, dispenser coating, and trowel coating can be used, and the contact pressure, resin viscosity, and other conditions can be set appropriately so that the thermosetting resin does not seep onto the sliding surface. When a composite member is formed by integrating a fabric with the surface of a substrate for a composite member, the thermosetting resin can also be used as an adhesive. That is, the thermosetting resin can be applied to the surface of the substrate for a composite member or the surface of the fabric on which the thermosetting resin is to be impregnated, and the two can be bonded together by pressure bonding or the like, and the thermosetting resin can be impregnated into one side so that the thermosetting resin is not exposed on the other side.

[0051] The fabric of the present invention thus obtained has low friction and sliding durability due to the combination of fluororesin fiber and fiber other than fluororesin fiber, and also has electrical conductivity due to the appropriate arrangement of conductive particles, so it also has the effect of suppressing triboelectric charging when subjected to sliding contact with an insulator. Therefore, by applying the fabric to sliding materials in which it is integrated with an insulating substrate, it is possible to obtain excellent sliding properties while preventing spark generation due to triboelectric charging.

[0052] The fabric of the present invention is preferably integrated with the surface of a substrate for a composite material to form a composite material, and the composite material is used as a member that slides against an insulating material, thereby effectively exhibiting excellent low friction and sliding durability while preventing spark generation due to frictional charging.

[0053] Examples of the present invention will be described below together with comparative examples.

[0054] The methods for measuring various properties used in the present examples are as follows.

[0055] (1) Fineness The fineness of the raw yarn used was measured in accordance with JIS L1013:2010 "Testing Methods for Chemical Fiber Filament Yarns" 8.3.B Method (simplified method). However, when measuring based on the fibers constituting the fabric, the fabric was disassembled and the fineness was measured using the same method. If the disassembled yarn cannot secure the amount of yarn required for the above measurement method, the results of tests using the maximum length and number of trials that can be secured shall be used instead.

[0056] (2) Weave Density In accordance with 8.6.1 of JIS L1096:2010 "Testing Methods for Woven and Knit Fabrics," the sample was placed on a flat table, and unnatural wrinkles and tension were removed. The number of warp threads and weft threads within a 50 mm interval was counted at five different points, and the average value for each unit length was calculated.

[0057] (3) Area ratio of fluororesin fiber The fabric was magnified 50 times with a Keyence microscope "VHX-2000" and photographed so that the sample (fabric) was visible in the entire field of view. The photographed area was determined as S ｔｏｔ , and the area occupied by fluororesin fiber A is S Ａ The area ratio of the fluororesin fiber was calculated using the following formula: Area ratio of fluororesin fiber A = S Ａ / S ｔｏｔ ×100[%] Note that the photographed area S ｔｏｔ and the area S occupied by fluororesin fiber A Ａ was calculated using the image analysis software "WinR00F2013" manufactured by Mitani Corporation.

[0058] (4) Basis weight According to JIS L1096:2010 "Testing methods for woven and knitted fabrics" 8.3.2a), the mass of a test piece of approximately 200 mm x 200 mm in standard condition is measured and divided by the area to obtain 1 m ２ Measurement was carried out on two test pieces, and the average value was taken as the basis weight.

[0059] (5) Amount of Conductive Particles, Binder Resin, and Thermosetting Resin Adhesion A mixture of conductive particles and binder resin is used, and the conductive particles are adhered to the fabric by a predetermined processing method. After that, the warp density (d ｗａｒｐ ) and warp density after processing (D ｗａｒｐ), weft density before processing (d ｗｅｆｔ ) and the weft density after processing (D ｗｅｆｔ ), and the basis weight before processing (w) and the basis weight after processing (W), the amount of the mixture adhered to the fabric, X, was calculated using the following formula: X = W - w × (d ｗａｒｐ / D ｗａｒｐ ) × (d ｗｅｆｔ / D ｗｅｆｔ ) Note that d ｗａｒｐ / D ｗａｒｐ and d ｗｅｆｔ / D ｗｅｆｔ is a correction term to take into account shrinkage before and after processing.

[0060] Next, the proportion α of conductive particles in the mixture and the proportion β of binder resin are used to calculate the adhesion amount W of conductive particles per unit area. α (g / m ２ ) and the amount of binder resin attached per unit area W β (g / m ２ ) was sought.

[0061] Furthermore, when the thermosetting resin is impregnated, the adhesion amount W of the thermosetting resin per unit area is calculated from the weight difference before and after the impregnation process. γ asked for.

[0062] When measuring the amount of conductive particles, binder resin, or thermosetting resin attached to a fabric, the substance to be measured may be eluted, or a substance other than the substance to be measured may be eluted, and the resulting weight loss may be used as the amount of attachment.

[0063] (6) Thickness The thickness of the fabric was measured under 23.5 kPa in accordance with 8.4. a) of JIS L1096:2010 “Testing methods for woven and knitted fabrics.”

[0064] (7) Adhesion amount per unit volume Adhesion amount W of the conductive particles α is divided by the thickness of the fabric (m) to obtain the adhesion amount per unit volume (g / m ３ ) was sought.

[0065] (8) Weight ratio of binder resin to fabric and weight ratio of thermosetting resin to fabric Adhesion amount of binder resin per unit area W βThe weight ratio of the fabric to the binder resin was calculated by dividing the weight by the basis weight of the fabric substrate. γ The weight ratio of the fabric substrate to the thermosetting resin was determined by dividing the weight by the basis weight of the fabric substrate.

[0066] (9) Presence or absence of adhesion of conductive particles The following observations were made on the fluororesin fiber and the fiber other than the fluororesin fiber.

[0067] A. Sliding surface A photograph of the fabric surface on the sliding surface side was taken at 200x magnification using a Keyence microscope "VHX-2000." Those in which the conductive particles were not visible were marked with an X, those in which the conductive particles were visible only in limited areas such as the intersection points of the threads were marked with an △, and those in which the conductive particles were visible all over were marked with an ◯.

[0068] B. Inner layer A cross section of the fabric in the thickness direction was magnified 500 times using a Keyence microscope "VHX-2000," and multiple photographs were taken so as to cover the entire area in the thickness direction, from the sliding surface to the back surface. If no conductive particles were visible in any of the photographs, it was marked with an "X," and if the conductive particles were visible in all photographs, it was marked with an "O." The magnification may be set appropriately within a range in which the conductive particles can be seen, depending on the particle size of the conductive particles.

[0069] C. Non-sliding surface (surface opposite to the sliding surface) A photograph of the fabric surface on the non-sliding surface side was taken at 200x magnification using a Keyence microscope "VHX-2000," and cases in which the conductive particles were not visible were marked with an X, cases in which the conductive particles were visible only in limited areas such as the intersection points of the threads were marked with an △, and cases in which the conductive particles were visible throughout were marked with an ◯.

[0070] The presence or absence of conductive particles was determined for each of the fluororesin fibers and fibers other than fluororesin fibers based on the above measurement results as follows: If no conductive particles were attached to any of A, B, or C: × If conductive particles were attached to any of A, B, or C: ○ (10) Friction Coefficient The friction coefficient was measured using a surface property measuring instrument, Tribogear® (TYPE: HEIDON®-14DR), manufactured by Shinto Chemical Co., Ltd. The fabric was attached to the indenter side and pressed against a glass plate at a pressure of 0.2 MPa. The static friction coefficient and kinetic friction coefficient were calculated from the resistance force when the indenter was moved at a speed of 100 mm / min for a sliding time of 6 seconds. The static friction coefficient was taken as the maximum value up to 1 second after the start of sliding, and the kinetic friction coefficient was taken as the average value for a total of 5 seconds from 1 second to 6 seconds after sliding.

[0071] (11) Sliding durability distance Measured by the ring wear test shown below.

[0072] According to Method A of JIS K7218:1986 "Sliding Abrasion Test Method for Plastics," a 30 mm x 30 mm sample of the woven fabric was placed on a 3 mm thick SUS plate of the same size and fixed in a sample holder. When measuring a fabric impregnated with a thermosetting resin from the back side, the fabric was impregnated with the thermosetting resin using the method described in the Examples so that the resin would not be exposed on the sliding surface, and then the fabric was bonded to the SUS plate before curing, and the test was performed in a state where the fabric was bonded to the SUS plate via the thermosetting resin.

[0073] The mating material was a hollow cylindrical ring made of S45C with an outer diameter of 25.6 mm, an inner diameter of 20 mm, and a length of 15 mm. The surface of the ring was polished with sandpaper to adjust the surface roughness to Ra = 0.8 μm ± 0.1. A roughness measuring instrument (Mitutoyo "SJ-201") was used to measure the roughness.

[0074] The ring abrasion tester was a Model EFM-III-EN manufactured by A&D, and the fabric was slid against the mating material at a pressure of 12.2 MPa and a speed of 200 mm / sec until the fabric broke. Tests that broke after a sliding distance of less than 100 m were rated D, those that broke after 100 m or more but less than 1000 m were rated C, those that broke after 1000 m or more but less than 10,000 m were rated B, and those that did not break even after 10,000 m of sliding were rated A.

[0075] (12) Durability of Electrical Conductivity In the ring abrasion test described in (11), the sample was abraded to a certain extent in the thickness direction by sliding under the following two conditions, and then the resistance value of the sliding location was measured using a tester (PC7000, manufactured by Sanwa Electric Instruments Co., Ltd.) Note that the following conditions were set as follows: condition (A) reproduces a situation in which only a part of the sliding surface is abraded when the fabric has a multilayer structure, and condition (B) reproduces a situation in which the entire sliding layer is abraded and the abrasion reaches the inner layer.

[0076] <Sliding conditions> (A) Pressure 12.2 MPa, speed 10 mm / sec, sliding time 4800 seconds (B) Pressure 12.2 MPa, speed 200 mm / sec, sliding time 4800 seconds After sliding under condition (A), the change in resistance value compared to before sliding was 1×10 ３ A is within 1 x 10 ３ Larger than 1x10 ５ Those within this range were rated as B, and others were rated as C. After sliding under condition (B), the change in resistance was 1×10 compared to before sliding. ３ Those within this range were rated as A, and others as B.

[0077] (13) Frictional Electrostatic Potential The frictional electrostatic potential between the test specimen and the cotton fabric was measured in accordance with JIS L1094:2014 “Test methods for electrostatic chargeability of woven and knitted fabrics” 7.2 B method.

[0078] Example 1, Comparative Example 1 A PTFE / PPS double woven fabric was woven using PTFE fiber ("Toyoflon" (registered trademark), manufactured by Toray Industries, Inc.) with a total fineness of 440 dtex and a single yarn count of 60 filaments for the warp and weft of the sliding surface, and PPS fiber ("Torcon" (registered trademark), manufactured by Toray Industries, Inc.) with a total fineness of 220 dtex and a single yarn count of 50 filaments for the warp and weft of the non-sliding surface. The weave structure of both the sliding surface and the non-sliding surface was a plain weave. The area ratio of the fluororesin fiber on the sliding surface of the obtained fabric was greater than the area ratio of the fluororesin fiber on the non-sliding surface. The fabric was then scoured in a scouring tank at 80°C and heat-set at 200°C. Next, carbon black (Lion Specialty Chemicals, "Lion Paste" (registered trademark) W-376R) as conductive particles and urethane resin (Nicca Chemical, "Evaphanol" (registered trademark) HA-207) as binder resin were dispersed and mixed in water, and the mixture was applied to a PTFE / PPS double woven fabric by dip-nip (DIP / NIP) processing. The fabric was then dried at 160°C for 2 minutes, and the conductive particles were attached to the PTFE / PPS double woven fabric via the binder resin.

[0079] Furthermore, a woven fabric after heat setting but before DIP / NIP processing was impregnated with epoxy resin (Cemedine's "Hi-Super" (registered trademark) 5) from the backside using a trowel to obtain a fabric for Comparative Example 1. No epoxy resin seeped out from the surface of the fabric for Comparative Example 1.

[0080] Examples 2 and 3: The backside of the fabric of Example 1 was impregnated with epoxy resin in the same manner as in Comparative Example 1, so that the mass ratio relative to the fabric substrate was the value shown in Table 1. No exudation of epoxy resin was observed from the surface of the fabric of Example 2. When observed from the surface of the fabric of Example 3, the epoxy resin was visible through the gaps at the intersection points of the warp and weft yarns on the sliding surface, confirming that some of the epoxy resin had exuded onto the fabric surface. When measuring the friction coefficient, only the outermost surface of the fabric being measured came into contact with the indenter, so there was no deterioration in the friction coefficient due to exudation of epoxy resin. During the sliding durability evaluation, the fluororesin fibers on the outermost surface were worn away, immediately exposing the epoxy resin. As a result, the friction coefficient monitored during the ring wear test increased and sliding durability decreased compared to Example 2.

[0081] Example 4, Comparative Example 2 Except for changing the PPS fiber used in Example 1 to nylon fiber (manufactured by Toray Industries, Inc.) with a total fineness of 235 dtex and 36 filaments, weaving, scouring, heat setting, DIP / NIP processing, and drying were carried out in the same manner as in Example 1 to produce a PTFE / nylon double-woven fabric with conductive particles adhered via a binder resin, and then the backside was impregnated with epoxy resin in the same manner as in Comparative Example 1. The area ratio of the fluororesin fiber on the sliding surface of the obtained fabric was greater than the area ratio of the fluororesin fiber on the non-sliding surface.

[0082] In addition, the fabric after heat setting but before DIP / NIP processing was impregnated with epoxy resin from the back side in the same manner as in Comparative Example 1 to produce a fabric as Comparative Example 2. No exudation of epoxy resin from the surface of the fabrics of Example 4 and Comparative Example 2 was observed.

[0083] Example 5, Comparative Example 3 Except for changing the PPS fiber used in Example 1 to a polyester fiber (manufactured by Toray Industries, Inc.) with a total fineness of 235 dtex and 36 filaments, weaving, scouring, heat setting, DIP / NIP processing, and drying were carried out in the same manner as in Example 1 to produce a PTFE / polyester double woven fabric with conductive particles adhered via a binder resin, and then the back side was impregnated with epoxy resin in the same manner as in Comparative Example 1. The area ratio of the fluororesin fiber on the sliding surface of the obtained fabric was greater than the area ratio of the fluororesin fiber on the non-sliding surface.

[0084] In addition, the fabric after heat setting but before DIP / NIP processing was impregnated with epoxy resin from the back side in the same manner as in Comparative Example 1 to produce a fabric as Comparative Example 3. No exudation of epoxy resin from the surface of the fabrics of Example 5 and Comparative Example 3 was observed.

[0085] Examples 6 to 7, Examples 9 to 12 Weaving, scouring, heat setting, DIP / NIP processing, and drying were carried out in the same manner as in Example 1, except that the amounts of binder resin and conductive particles attached were changed as shown in Tables 1 and 2, to produce PTFE / PPS double woven fabrics with conductive particles attached via the binder resin.

[0086] Example 8 The woven fabric of Example 7 was impregnated with an epoxy resin from the back side in the same manner as in Comparative Example 1.

[0087] Example 13 A PTFE / PPS double woven fabric having conductive particles adhered via the binder resin was produced by weaving, scouring, heat setting, and drying in the same manner as in Example 1, except that the coating method for the binder resin and conductive particles was changed to a knife coating method from the back side, and the adhesion amount and distribution of the conductive particles were changed as shown in Table 2.

[0088] Example 14 A PTFE / PPS double woven fabric having conductive particles adhered via the binder resin was produced by weaving, scouring, heat setting, and drying in the same manner as in Example 1, except that the coating method for the binder resin and conductive particles was changed to a knife coating method from the surface, and the adhesion amount and distribution of the conductive particles were changed as shown in Table 2.

[0089] Example 15: A PTFE / PPS single-ply fabric was woven using alternating warp and weft yarns of PTFE fiber ("Toyoflon"®, Toray Industries, Inc.) with a total fineness of 440 dtex and 60 filaments and PPS fiber ("Torcon"®, Toray Industries, Inc.) with a total fineness of 220 dtex and 50 filaments. The fabric was then scouring, heat-setting, DIP / NIP processing, and drying in the same manner as in Example 1 to produce a PTFE / PPS single-ply fabric with conductive particles adhered thereto via a binder resin. The resulting PTFE / PPS single-ply fabric had the same area ratio of the fluororesin fiber on one side as the area ratio of the fluororesin fiber on the other side. The fabric was then impregnated with epoxy resin from the back side in the same manner as in Comparative Example 1.

[0090] Comparative Example 4 PTFE fiber ("Toyoflon" (registered trademark) manufactured by Toray Industries, Inc.) having a total fineness of 440 dtex and 60 filaments per single yarn was used for the warp and weft to weave in a plain weave, and then the fabric was refined and heat-set in the same manner as in Example 1 to produce a PTFE single-ply fabric, which was then impregnated with an epoxy resin from the back side in the same manner as in Comparative Example 1.

[0091] Comparative Example 5 A composite yarn was produced by plying and twisting a PTFE fiber ("Toyoflon"®, Toray Industries, Inc.) with a total fineness of 440 dtex and 60 filaments with a conductive polyester fiber ("Luana"®, Toray Industries, Inc.) with a total fineness of 22 dtex and 1 filament in the S direction at a twist rate of 300 T / m. The same weaving, scouring, and heat setting procedures as in Example 1 were carried out, except that the composite yarn was used as the warp and weft of the sliding surface. A PTFE / PPS double-woven fabric with conductive fibers composited on the sliding surface was produced, and the reverse side was then impregnated with epoxy resin in the same manner as in Comparative Example 1. The area ratio of the fluororesin fiber on the sliding surface of the resulting fabric was greater than the area ratio of the fluororesin fiber on the non-sliding surface.

[0092] Comparative Example 6 The woven fabric of Comparative Example 4 was subjected to DIP / NIP processing and drying in the same manner as in Example 1 to produce a PTFE single-ply woven fabric to which conductive particles were attached via a binder resin, and the back side was then impregnated with epoxy resin in the same manner as in Comparative Example 1.

[0093] Tables 1 to 3 show the evaluation results of the fabric structure, frictional electrification voltage, friction coefficient, and sliding durability distance for the woven fabrics described in the Examples and Comparative Examples.

[0094] The woven fabrics described in Examples 1 and 6 to 14 were evaluated for durability of electrical conductivity, and the evaluation results are summarized in Table 4. In the evaluation of durability of electrical conductivity of the woven fabrics described in Table 4, after sliding under condition (A), some of the PTFE fibers on the surface were worn away, and a self-lubricating film of PTFE was formed on the surface. After sliding under condition (B), it was visually confirmed that all of the PTFE fibers on the surface were worn away, and the PPS fiber layer on the back surface was exposed.

[0095]

[0096]

[0097]

[0098]

Claims

1. A fabric comprising a fabric substrate made of fluororesin fibers and fibers other than fluororesin fibers, wherein conductive particles are adhered to both the fluororesin fibers and the fibers other than fluororesin fibers, and the conductive particles are adhered to the fluororesin fibers and the fibers other than fluororesin fibers via a binder resin that is a thermoplastic resin.

2. The fabric according to claim 1 , wherein the fiber other than the fluororesin fiber is a polyphenylene sulfide fiber.

3. The fabric according to claim 2 , wherein a mass ratio of the binder resin to the fabric substrate is 0.01% or more and 30% or less.

4. The amount of the conductive particles attached to the fabric per unit volume is 3000 g / m ３ More than 50000g / m ３ 3. The fabric of claim 1 or 2, wherein:

5. The fabric according to claim 1 or 2, wherein the conductive particles are adhered to the entire surface of the fabric in the thickness direction.

6. The fabric according to claim 1 or 2, wherein the fabric substrate has a double structure.

7. 3. The fabric according to claim 1, wherein an area ratio of the fluororesin fibers on one surface of the fabric is lower than an area ratio of the fluororesin fibers on the other surface of the fabric.

8. The fabric according to claim 1 or 2, wherein a thermosetting resin is contained within a surface layer on one side of the fabric, and the thermosetting resin is not exposed on the other side.

9. 3. The fabric according to claim 1, which is integrated with a surface of a substrate for a composite material to form the composite material, and the composite material is used to slide against an insulating material.