JP5956162B2 - Friction transmission belt and manufacturing method thereof - Google Patents

Description

  The present invention relates to a friction transmission belt that forms a rib portion using a mold without polishing, and a manufacturing method thereof.

  Even in the rubber industry, high performance and high performance are desired for automotive parts. Among such rubber products used for automobile parts, there is a power transmission belt, which is widely used for power transmission of auxiliary drives such as an air compressor and an alternator of an automobile. In recent years, there has been a strict demand for quietness in the living environment, and in particular, in automobile drive devices, since sounds other than engine noise are abnormal noise, countermeasures against belt sounding have been demanded.

  Friction transmission V-belts used as power transmission belts are roughly classified into a polishing belt that forms ribs by polishing and a belt that molds ribs using a mold (mold forming belt), depending on the manufacturing method. it can. Mold molding belts are obtained by pressing raw rubber against the mold and vulcanizing it. When air is interposed between the mold and rubber, an uneven surface is formed on the belt surface (pulley engagement or contact surface). It becomes non-uniform and causes abnormal noise due to misalignment of pulleys during belt running. For this reason, in the method of manufacturing a mold forming belt, it is necessary to add an air bleeding material on the rib rubber in order to extract air from the mold. Generally, a non-woven fabric is used as the air release material, and air accumulation is prevented by winding the non-woven fabric around the belt surface. However, even in the method using a nonwoven fabric, when the nonwoven fabric is wound, the joint portions of adjacent nonwoven fabrics overlap (stack) or become a butt joint (a gap is formed), and a step or uneven surface is generated at this joint portion. . Furthermore, in the friction transmission V-belt, in order to suppress fluctuations in rotational speed, slip noise generated under high load conditions, and noise generated due to adhesive rubber having adhesive wear adhering to the groove bottom between ribs, It is also necessary to reduce the surface friction coefficient.

  Japanese Patent No. 4251870 (Patent Document 1) includes a main body having an elastic body and having a tensile member along the longitudinal direction, the main body having a predetermined shape and engaging with a pulley. A non-woven fabric member, which is a pulley engaging region having an engaging surface and on which irregularly oriented fibers are arranged, is obtained by vulcanizing the material of the elastic body, so that both the elastic body and the non-woven fabric member A belt having the pulley engagement region mixed with the elastic body so as to exist over the entire surface of the pulley engagement surface, the elastic body further including fiber filling inside the pulley engagement region is disclosed. Has been. In this document, a nonwoven fabric member made of cellulose is mixed on the pulley engaging surface so as not to have a clear boundary with the rubber of the main body. Further, the nonwoven member may be formed from one or more layers and is described as having the advantage of escaping gas generated in the molding process.

  Japanese Patent Laid-Open No. 2010-101289 (Patent Document 2) discloses a transmission belt having ethylene-α-olefin elastomer-based elastomer teeth, wherein the elastomer teeth are covered with a barrier layer made of a thermoplastic material, and The barrier layer is covered with an outer cover formed of woven or non-woven fabric, and the outer cover that is at least on the flank of the elastomeric teeth is partially included within a portion of the thickness of the barrier layer. A transmission belt is disclosed. This document describes that the woven fabric or non-woven fabric forming the cover can be formed of a fiber coated with polyethylene with a material having a melting point higher than the vulcanization temperature in order to retain the fiber structure after vulcanization. Yes.

  However, in these belts, since the pulley engaging surface uses a nonwoven fabric, the joint portion is also non-uniform and steps are formed, and abnormal noise is generated during belt running.

  Japanese Patent Application Laid-Open No. 2009-533606 (Patent Document 3) discloses a transmission belt with ribs having a tooth portion made of an ethylene / α-olefin elastomer-based elastomer, and at least a side surface of the tooth portion has a molecular weight of 50000 g / A ribbed transmission belt is disclosed that is covered with a film of a thermoplastic resin that is at least partially crosslinked and contains at least 30% of at least one low density polyethylene that is between mol and 200000 g / mol. . This document describes that a thermoplastic resin is applied to a rubber surface in an uncrosslinked or partially crosslinked state, and then partially or completely crosslinked in a belt vulcanization process.

  However, it is difficult to form a smooth surface by coating, and a cross-linking step is required, and productivity is low.

  Japanese Patent Application Laid-Open No. 2007-170587 (Patent Document 4) has an expansion portion and a compression portion composed of a plurality of rib portions extending in the belt circumferential direction, and the core wire is extended along the belt longitudinal direction. V-ribbed belt embedded in between, and the inner layer of the rib part is made of a rubber composition made of an ethylene-α-olefin elastomer, and the ultrahigh molecular weight polyethylene powder adheres to the surface of the rib part in contact with the pulley. A V-ribbed belt is disclosed in which a friction transmission layer is formed. This document describes, as the friction transmission layer, a layer obtained by vulcanizing a rubber paste in which an ultra-high molecular weight polyethylene powder is blended with an ethylene-α-olefin elastomer.

  However, in this belt, the ultra high molecular weight polyethylene is hardly exposed on the surface by the vulcanized rubber, and the reduction in the friction coefficient of the belt surface cannot be improved.

Japanese Patent No. 4251870 (Claim 1, paragraphs [0014] [0017] [0022]) JP 2010-101489 A (Claim 1, paragraph [0051]) JP 2009-533606 A (Claims, paragraphs [0026] to [0040], [0050] to [0056]) JP 2007-170587 A (Claim 1, paragraphs [0021] [0030])

  Accordingly, an object of the present invention is to provide a friction transmission belt capable of suppressing the generation of abnormal noise and noise during traveling in a mold forming belt, and a method for manufacturing the same.

  Another object of the present invention is to provide a friction transmission belt having high productivity, a uniform surface thickness, and a low coefficient of friction, and a method for producing the same.

  Another object of the present invention is to provide a friction transmission belt capable of easily controlling the friction coefficient of the belt surface and a method for manufacturing the same.

  Still another object of the present invention is to provide a friction transmission belt excellent in durability and a method for manufacturing the same.

  As a result of intensive studies to achieve the above-mentioned problems, the inventors of the present invention have determined that the surface of the compression rubber layer for engaging or contacting the pulley is formed of a thermoplastic resin in the friction transmission belt, and at least a film-like portion is formed. It has been found that by covering with a skin layer, it is possible to suppress the generation of abnormal noise and noise during running in the mold forming belt, and the present invention has been completed.

  That is, the friction transmission belt of the present invention is a friction transmission belt including at least a core wire and a compression rubber layer for engaging or contacting with a pulley, and the surface of the compression rubber layer is made of a thermoplastic resin. It is formed and covered with a skin layer having at least a film-like part. The thermoplastic resin may have a melting point or softening point below the vulcanization temperature of the compressed rubber layer. The thermoplastic resin may be at least one selected from an olefin resin and a thermoplastic elastomer. The thermoplastic resin may not be crosslinked. The skin layer may be a fabric melt (melt) formed of thermoplastic resin fibers. The fabric may be a non-woven fabric. The skin layer may have an average thickness of 0.01 to 0.5 mm. The skin layer may be a film and may not have a fiber structure. The compressed rubber layer may not contain short fibers. The friction transmission belt of the present invention may be molded with a mold without being polished, and may be, for example, a friction transmission V belt or a friction transmission V-ribbed belt.

In the present invention, a core spinning process for winding a core wire around a cylindrical drum, a compression rubber layer winding step for winding an unvulcanized rubber sheet for forming a compressed rubber layer on the wound core wire, and winding On the unvulcanized rubber sheet, a skin layer winding step of winding a fabric formed of thermoplastic resin fibers, pressing the unvulcanized rubber wrapped with the core wire and the fabric against a mold, and vulcanizing and molding, Also included is a method for producing the friction transmission belt, which includes a vulcanization molding step of melting the fabric on the surface of the obtained compressed rubber layer to form a skin layer having a film-like portion. In the skin layer winding step, a plurality of layers of fabric may be overlapped and wound. In the skin layer winding step, the fabric may be wound in an oblique direction with respect to the circumferential direction of the belt. The fabric may be a spunbonded nonwoven fabric having a basis weight of 15 to 80 g / ^{m 2.}

  In the present invention, in the friction transmission belt, the surface of the compression rubber layer for engaging with or contacting the pulley is formed of a thermoplastic resin and is covered with a skin layer having at least a film-like portion. Despite being a molded belt, it is possible to suppress the generation of abnormal noise and noise during traveling. Moreover, the friction transmission belt of the present invention has high productivity, a uniform surface thickness, and a low coefficient of friction. Moreover, the friction coefficient of the belt surface can be easily controlled by selecting the type of the thermoplastic resin for the skin layer. Furthermore, since the friction coefficient of the belt surface can be reduced by the skin layer, it is not necessary to mix short fibers in the compressed rubber layer, durability can be improved, and belt life can be improved.

FIG. 1 is a schematic sectional view showing an example of the friction transmission belt of the present invention. FIG. 2 is a schematic perspective view showing another example of the friction transmission belt of the present invention. FIG. 3 is a schematic cross-sectional view showing a state in which each member sheet that is a raw material of the friction transmission belt is wound around a cylindrical forming drum in the embodiment. FIG. 4 is a schematic perspective view (a) and a schematic cross-sectional view (b) showing a state where the forming drum of FIG. 3 around which each member sheet is wound is set in a vulcanization mold. FIG. 5 is a schematic perspective view (a) and a schematic cross-sectional view (b) showing a state where the flexible jacket in the forming drum of FIG. 4 is expanded. 6 is a microscope photograph of the cross section of the rib portion of the V-ribbed belt obtained in Example 1. FIG.

[Friction transmission belt]
The friction transmission belt of the present invention is a friction transmission belt comprising at least a core wire and a compressed rubber layer for engaging or contacting with a pulley, and the surface of the compressed rubber layer is covered with a specific skin layer. Has been. Since the skin layer is formed of an uncrosslinked thermoplastic resin, the friction coefficient does not decrease too much and has an appropriate friction coefficient. The skin layer having such characteristics does not impair the function as a friction transmission belt and also suppresses the generation of slip noise. Furthermore, when a fabric having a fiber structure is melted (melted) to produce a skin layer, the fabric before melting acts as an air venting material, and it is possible to suppress the formation of an uneven structure due to air accumulation and to melt after vulcanization. Forming a uniform skin layer and reducing the friction coefficient of the surface. Therefore, in the present invention, a friction transmission belt having a low surface friction coefficient can be manufactured even by a molding method using a mold.

  FIG. 1 is a schematic sectional view showing an example of a friction transmission belt (V-ribbed belt) according to the present invention, which is a schematic sectional view cut in the belt longitudinal direction.

  In this example, the V-ribbed belt 1 has rib portions 7 extending in a plurality of rows along the longitudinal direction of the belt on the inner peripheral surface of the belt body, and a direction orthogonal to the longitudinal direction of the rib portions 7. The cross-sectional shape is a trapezoidal shape whose width decreases from the belt outer peripheral side (the side that does not have the rib portion and does not engage with the pulley) toward the inner peripheral side (taperes toward the tip).

  The V-ribbed belt 1 has a laminated structure, and an extension layer (extension rubber layer) 5 formed of a rubber composition containing short fibers 4 from the outer peripheral side to the inner peripheral side of the belt main body, a core wire 3. A compressed rubber layer 6 having the rib portion 7 and a film-like skin layer 8 formed of a thermoplastic resin are sequentially laminated.

  Specifically, the core wire 3 is embedded in the main body along the longitudinal direction of the belt, and a part thereof is in contact with the stretch layer 5 and the remaining part is in contact with the compression rubber layer 6. The short fibers 4 contained in the stretched layer 5 are oriented in a random direction. The skin layer 8 is formed with a substantially uniform thickness by partially or completely melting a fabric having a fiber structure.

  FIG. 2 is a schematic perspective view showing another example of the friction transmission belt (V-ribbed belt) of the present invention.

  In this example, the V-ribbed belt 1 is different from the V-ribbed belt 1 shown in FIG. 1 in the laminated structure, and the stretched layer 5 and the core wire 3 formed of the fabric are provided from the outer peripheral side to the inner peripheral side of the belt main body. An adhesive rubber layer 2 in which a plurality of core wires 3 extending along the belt longitudinal direction are embedded, a compressed rubber layer 6 having ribs 7, and a film-like skin layer 8 formed of a thermoplastic resin are sequentially laminated. In this V-ribbed belt 1, the stretch layer 5 is formed of a fabric (reinforcing fabric) such as a canvas and is exposed on the outer peripheral surface (rear surface).

(Skin layer)
The skin layer is formed of a thermoplastic resin and covers the surface of the compressed rubber layer with a substantially uniform thickness, thereby reducing the friction coefficient of the belt surface and suppressing the generation of noise and noise during running.

  The thermoplastic resin preferably has a melting point (or softening point) equal to or lower than the vulcanization temperature of the compressed rubber layer, for example, 0 to 100 ° C., preferably 3 to 80 ° C., more preferably 5 than the vulcanization temperature. It may have a low melting point of ˜70 ° C. (especially 10 to 60 ° C.). If the melting point of the thermoplastic resin is too high, the thermoplastic resin will not melt in the vulcanization process, making it difficult to form a uniform skin layer. On the other hand, if it is too low, the mechanical properties of the skin layer will be reduced, and driving It becomes easy to break by friction. The vulcanization temperature of the compressed rubber layer is often about 150 to 180 ° C., and the melting point of the thermoplastic resin is, for example, 165 ° C. or less (for example, 80 to 165 ° C.), preferably 150 ° C. or less (for example, 90 to 150 ° C.), more preferably about 130 ° C. or less (for example, 100 to 130 ° C.).

  Furthermore, in the present invention, as the thermoplastic resin, a resin that is not substantially cross-linked is used because it is melted and uniformized in the vulcanization step of the compressed rubber layer and an appropriate friction coefficient can be secured. The

  Examples of the thermoplastic resin include olefin resins, acrylic resins, vinyl resins, styrene resins, polyester resins, polyamide resins, polycarbonate resins, polyurethane resins, cellulose resins, and thermoplastic elastomers. It is done. These thermoplastic resins can be used alone or in combination of two or more.

  Of these thermoplastic resins, olefin-based resins and thermoplastic elastomers are preferred because they can easily form a smooth surface with few irregularities, reduce the friction coefficient, and have high versatility.

(1) Olefin resin The olefin resin is an α-olefin such as ethylene, propylene, 1-butene, 2-butene, 1-pentene, 1-hexene, 3-methylpentene, 4-methylpentene (in particular, ethylene, A polymer having α-C _2-6 olefin such as propylene as a main polymerization component may be used.

Examples of the copolymerizable monomer other than the α-olefin include (meth) acrylic monomers [for example, (meth) acrylic acid C ₁ such as methyl (meth) acrylate and ethyl (meth) acrylate. _-6 alkyl ester etc.], unsaturated carboxylic acids (eg maleic anhydride etc.), vinyl esters (eg vinyl acetate, vinyl propionate etc.), dienes (butadiene, isoprene etc.) and the like. These monomers can be used alone or in combination of two or more.

  Examples of olefin resins include polyethylene resins [low, medium or high density polyethylene, linear low density polyethylene, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-propylene-butene-1]. Copolymer, ethylene- (4-methylpentene-1) copolymer, etc.], polypropylene resin (polypropylene, propylene-ethylene copolymer, propylene-butene-1 copolymer, propylene-ethylene-butene-1 copolymer) Polymer) and the like. The melting point of the olefin resin may be controlled by copolymerizing a copolymerizable monomer at a specific ratio. For example, ethylene may be copolymerized with a polypropylene resin to lower the melting point. These olefin resins can be used alone or in combination of two or more.

  Of these olefin resins, polyethylene resins such as polyethylene and polypropylene resins such as polypropylene are preferred, and polyethylene resins such as low density polyethylene are particularly preferred from the viewpoint of easy melting at the vulcanization temperature.

(2) Thermoplastic elastomer Examples of the thermoplastic elastomer include olefin elastomers, styrene elastomers, polyester elastomers, polyamide elastomers, and the like.

  Olefin-based elastomers include hard segments formed from polyolefins such as polyethylene and polypropylene, and soft segments formed from rubber components such as olefin rubber, diene rubber, acrylic rubber, butyl rubber, nitrile rubber, and natural rubber. The elastomer etc. which have can be illustrated.

  As the styrene elastomer, an elastomer having a hard segment formed of a styrene polymer such as polystyrene and a soft segment formed of a rubber component such as a diene rubber such as polybutadiene or polyisopropylene or a hydrogenated product thereof. Etc. can be exemplified.

  Examples of the polyester elastomer include an elastomer having a hard segment formed of polyalkylene arylate such as polybutylene terephthalate or polybutylene naphthalate and a soft segment formed of aliphatic polyether or aliphatic polyester. .

  The polyamide-based elastomer has a hard segment formed of an aliphatic polyamide such as polyamide 6, polyamide 66, and polyamide 12, and a soft segment formed of an aliphatic polyether, aliphatic polyester, aliphatic carbonate, or the like. An elastomer etc. can be illustrated.

  These thermoplastic elastomers can be used alone or in combination of two or more. Among these thermoplastic elastomers, hard segments formed from polyolefins such as polyethylene and olefinic rubbers such as ethylene-propylene-nonconjugated diene copolymer rubber (EPDM) because they are easily melted at the vulcanization temperature. An olefin-based elastomer having a soft segment formed of

  In the present invention, the skin layer is preferably a melt of a fabric formed of thermoplastic resin fibers from the viewpoint of suppressing occurrence of irregularities due to air accumulation during molding.

  The fabric is not particularly limited as long as it has a fiber structure, and may be a nonwoven fabric, a woven fabric, a knitted fabric, or the like. Of these, non-woven fabrics are preferred because they have high air permeability and a high effect of suppressing air accumulation.

  Examples of the method for producing the nonwoven fabric include a spun bond method, a chemical bond method, a thermal bond method, and a needle punch method. Of these production methods, the spunbond method is preferred. The spunbond nonwoven fabric obtained by the spunbond method is composed of filaments, so the nonwoven fabric obtained by thermocompression bonding has high tensile strength and tear strength, and has high dimensional stability in the winding process during belt molding. Workability can be improved.

The basis weight of the fabric (particularly the nonwoven fabric) can be selected from a range of about 10 to 100 g / m ² , for example, 15 to 80 g / m ² , preferably 18 to 75 g / m ² , and more preferably about ²⁰ to 70 g / m ^2. It is. If the basis weight is too small, the tensile strength and tear strength of the nonwoven fabric are reduced, and the film thickness tends to be non-uniform even when melted. On the other hand, if the basis weight is too large, the amount of fibers increases, the thermal conductivity decreases, making it difficult to form a film by melting the fibers, and the air permeability is lowered, so that air accumulation is likely to occur.

  The average thickness of the fabric (particularly the nonwoven fabric) is, for example, about 0.1 to 1 mm, preferably about 0.2 to 0.6 mm, and more preferably about 0.3 to 0.5 mm.

  In the present invention, it is preferable that the thin fabric (nonwoven fabric) having the basis weight and thickness is wound a plurality of times (multiple layers) and adjusted so that the thickness of the skin layer falls within the above range. For example, the number of windings may be, for example, 2 to 10 times, preferably 2 to 6 times, and more preferably about 2 to 4 times.

  The shape of the fiber constituting the fabric is not particularly limited, and examples of the cross-sectional shape (cross-sectional shape perpendicular to the fiber length direction) include a substantially circular shape, an elliptical shape, a flat shape, and a polygonal shape. Of these shapes, a substantially circular shape is preferable because a film having a uniform thickness can be easily formed.

  The fiber is not limited to a fiber formed of a single thermoplastic resin, and may be a composite fiber obtained by combining a plurality of types of thermoplastic resins. The composite fibers are classified into, for example, a core-sheath type, a sea-island type, a blend type, a parallel type (multilayer bonding type), and a radial type depending on the difference in the cross-sectional structure. Of these, the sheath portion may be a core-sheath type composite fiber formed of a thermoplastic resin having a low melting point, but the nonwoven fabric is sufficiently melted to easily form a skin layer having a uniform thickness. A single-phase fiber formed of a low-melting thermoplastic resin alone or a composite fiber formed of a combination of low-melting thermoplastic resins is particularly preferable.

  The average fineness of the fiber is, for example, about 5 to 60 dtex, preferably about 5 to 40 dtex, and more preferably about 15 to 30 dtex. If the fineness is too small, the strength of the non-woven fabric is lowered and the handleability is lowered, and if it is too large, it is difficult to form a uniform film.

  In the present invention, even if the skin layer before vulcanization is formed of a fabric, the thermoplastic resin constituting the fiber has a melting point that can be melted at the vulcanization temperature. After molding, the fiber structure is partially or completely disappeared by melting of the thermoplastic resin, and a film-like skin layer having a substantially uniform thickness can be formed.

  The skin layer has at least a film-like part (non-fiber part) and has a substantially uniform thickness. The area ratio of the film-like portion to the entire skin layer is, for example, 50% or more, preferably 60% or more, more preferably 70% or more (particularly 90% or more), and the substantially entire surface is film-like (substantially 100%). Certain layers are particularly preferred. That is, even if the skin layer is a layer obtained by melting a fabric having a fiber structure, a layer having a fiber structure disappearing due to melting of the thermoplastic resin and having substantially no fiber structure is particularly preferable. . When the ratio of the film-like portion is small, the uniformity of the belt surface is lowered, and abnormal noise and noise are likely to occur during traveling.

  In addition, in this invention, the area ratio of the film-form part with respect to the whole skin layer observes the film surface with the naked eye, a film-form part (smooth part which does not have a fiber-like or granular surface), and a non-film-form part (fiber Area ratio of the non-smooth part having a surface or a granular surface), and the ratio of the fiber structure and granular structure remaining inside the film is not taken into consideration.

  The average thickness of the skin layer is, for example, about 0.01 to 0.5 mm, preferably about 0.03 to 0.3 mm, and more preferably about 0.05 to 0.15 mm (particularly 0.06 to 0.15 mm). . If the skin layer is too thin, it will be worn in a short time and the friction coefficient of the belt surface will increase. When the thickness of the skin layer is too large, the flexibility of the skin layer is lowered, and peeling from the surface of the compressed rubber layer and cracking are likely to occur.

(Compressed rubber layer)
The rubber composition for forming the compressed rubber layer is not particularly limited, but a rubber composition containing a rubber component and a vulcanizing agent or a crosslinking agent is usually used. In particular, the present invention forms an unvulcanized rubber layer from a rubber composition containing sulfur or an organic peroxide (particularly an organic peroxide vulcanized rubber composition), and vulcanizes or crosslinks the unvulcanized rubber layer. Useful to do.

  Examples of rubber components include vulcanizable or crosslinkable rubbers such as diene rubbers (natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber, styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (nitrile rubber), hydrogenated nitrile rubber. , Mixed polymers of hydrogenated nitrile rubber and unsaturated carboxylic acid metal salt, etc.), ethylene-α-olefin elastomer, chlorosulfonated polyethylene rubber, alkylated chlorosulfonated polyethylene rubber, epichlorohydrin rubber, acrylic rubber, silicone rubber, Examples thereof include urethane rubber and fluorine rubber. These rubber components can be used alone or in combination of two or more.

  Of these, ethylene-α-olefin elastomers (ethylene-α-olefin rubbers) are preferred because they do not contain harmful halogens, have ozone resistance, heat resistance, cold resistance, and are excellent in economic efficiency. Furthermore, since the ethylene-α-olefin elastomer has low water wettability compared to other rubbers, it can significantly improve power transmission and quietness during water injection.

  Examples of the ethylene-α-olefin elastomer (ethylene-α-olefin rubber) include ethylene-α-olefin rubber and ethylene-α-olefin-diene rubber.

Examples of the α-olefin include chain α-C _3-12 olefins such as propylene, butene, pentene, methylpentene, hexene, and octene. The α-olefin can be used alone or in combination of two or more. Of these α-olefins, α-C _3-4 olefins (particularly propylene) such as propylene are preferred.

  Examples of the diene monomer usually include non-conjugated diene monomers such as dicyclopentadiene, methylene norbornene, ethylidene norbornene, 1,4-hexadiene, and cyclooctadiene. These diene monomers can be used alone or in combination of two or more.

  Typical ethylene-α-olefin elastomers include, for example, ethylene-α-olefin rubber (ethylene-propylene rubber (EPR)), ethylene-α-olefin-diene rubber (ethylene-propylene-diene copolymer (EPDM, etc.)). And the like. A preferred ethylene-α-olefin elastomer is EPDM.

  In the ethylene-α-olefin rubber, the ratio (mass ratio) of ethylene and α-olefin is the former / the latter = 40/60 to 90/10, preferably 45/55 to 85/15 (for example, 50/50 to 82/18), more preferably 55/45 to 80/20 (for example, 55/45 to 75/25). The proportion of diene can be selected from a range of about 4 to 15% by mass, for example, 4.2 to 13% by mass (for example, 4.3 to 12% by mass), preferably 4.4 to 11.5% by mass. % (For example, 4.5-11 mass%) may be sufficient. The iodine value of the ethylene-α-olefin rubber containing the diene component may be, for example, about 3 to 40 (preferably 5 to 30, more preferably 10 to 20). If the iodine value is too small, vulcanization of the rubber composition will be insufficient and wear and adhesion will easily occur, and if the iodine value is too large, the scorch of the rubber composition will become short and difficult to handle, and it will be heat resistant. Tends to decrease.

  As the organic peroxide, organic peroxides usually used for crosslinking of rubber and resin, for example, diacyl peroxide, peroxy ester, dialkyl peroxide (for example, dicumyl peroxide, t-butyl cumyl peroxide) are used. Oxide, 1,1-di-butylperoxy-3,3,5-trimethylcyclohexane 2,5-dimethyl-2,5-di (t-butylperoxy) -hexane, 1,3-bis (t-butyl) Peroxy-isopropyl) benzene, di-t-butyl peroxide, etc.). These organic peroxides can be used alone or in combination of two or more. Further, the organic peroxide is preferably a peroxide having a half-life of about 150 to 250 ° C. (for example, 175 to 225 ° C.) by thermal decomposition.

  The ratio of the vulcanizing agent or the crosslinking agent (especially organic peroxide) is 1 to 10 parts by mass, preferably 1 in terms of solid content with respect to 100 parts by mass of the rubber component (such as ethylene-α-olefin elastomer). It is 2-8 mass parts, More preferably, it is about 1.5-6 mass parts (for example, 2-5 mass parts).

  The rubber composition may further contain a vulcanization accelerator. Examples of the vulcanization accelerator include thiuram accelerators, thiazol accelerators, sulfenamide accelerators, bismaleimide accelerators, urea accelerators, and the like. These vulcanization accelerators can be used alone or in combination of two or more. The proportion of the vulcanization accelerator is, for example, 0.5 to 15 parts by mass, preferably 1 to 10 parts by mass, and more preferably about 2 to 5 parts by mass in terms of solid content with respect to 100 parts by mass of the rubber component. is there.

  The rubber composition may further contain a co-crosslinking agent (cross-linking aid or co-vulcanizing agent) in order to increase the degree of cross-linking and prevent adhesive wear and the like. Examples of co-crosslinking agents include conventional crosslinking aids such as polyfunctional (iso) cyanurates [eg, triallyl isocyanurate (TAIC), triallyl cyanurate (TAC), etc.], polydienes (eg, 1,2-polybutadiene). Etc.), metal salts of unsaturated carboxylic acids [eg, zinc (meth) acrylate, magnesium (meth) acrylate, etc.], oximes (eg, quinone dioxime), guanidines (eg, diphenyl guanidine, etc.), Multifunctional (meth) acrylate [for example, ethylene glycol di (meth) acrylate, butanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, etc.], bismaleimides (N-N'-m-phenylenebismaleimide Etc.). These crosslinking aids can be used alone or in combination of two or more. The ratio of the crosslinking aid (total amount when combining multiple types) is, for example, 0.01 to 10 parts by mass, preferably 0.05 to 8 parts by mass, based on 100 parts by mass of rubber, in terms of solid content. More preferably, it is about 0.1-5 mass parts.

  If necessary, the rubber composition may be prepared by adding conventional additives such as a vulcanization aid, a vulcanization accelerator, a vulcanization retarder, a reinforcing agent (carbon oxide, silicon oxide such as hydrous silica), a filler ( Clay, calcium carbonate, talc, mica, etc.), metal oxides (eg, zinc oxide, magnesium oxide, calcium oxide, barium oxide, iron oxide, copper oxide, titanium oxide, aluminum oxide, etc.), softeners (paraffin oil, naphthene) Oils such as system oils and process oils), processing agents or processing aids (stearic acid, metal stearate, wax, paraffin, fatty acid amide, etc.), anti-aging agents (antioxidants, thermal anti-aging agents, bending) Anti-cracking agent, anti-ozone degradation agent, etc.), coloring agent, tackifier, plasticizer, coupling agent (silane coupling agent, etc.), stabilizer (purple) Linear absorption agents, antioxidants, antiozonants, thermal stabilizers, etc.), a lubricant, a flame retardant, an antistatic agent and the like. The metal oxide may act as a crosslinking agent. These additives can be used alone or in combination of two or more.

  The proportion of these additives can be selected from a conventional range depending on the type. For example, the proportion of the reinforcing agent (carbon black, silica, etc.) is 10 to 200 parts by mass (particularly 20 to 200 parts by mass with respect to 100 parts by mass of the rubber component). 150 parts by mass), the ratio of the metal oxide (such as zinc oxide) may be about 1 to 15 parts by mass (particularly 2 to 10 parts by mass), and softener (oil such as paraffin oil) 1-30 mass parts (especially 5-25 mass parts) may be sufficient, and the ratio of a processing agent (stearic acid etc.) is 0.1-5 mass parts (especially 0.5-3 mass parts). Part) degree.

  In the present invention, it is preferable that the rubber composition of the compressed rubber layer (particularly the rubber composition forming the rib portion) does not substantially contain fibers such as short fibers. In general, short fibers are often contained in the rib portion of the compressed rubber layer, but in the present invention, the friction coefficient on the surface of the compressed rubber layer can be reduced by forming a skin layer. Therefore, it is not necessary to mix short fibers, and the rib portion of the compressed rubber layer does not contain short fibers, so that the belt life can be improved.

  The thickness of the compressed rubber layer is, for example, about 2 to 25 mm, preferably about 3 to 16 mm, and more preferably about 4 to 12 mm.

(Adhesive rubber layer)
When the friction transmission belt has an adhesive rubber layer for embedding the core wire like the belt shown in FIG. 2, the rubber composition similar to the compression rubber layer (such as ethylene-α-olefin elastomer) is also used for the adhesive rubber layer. A rubber composition containing a rubber component) can be used. In the rubber composition of the adhesive rubber layer, as the rubber component, the same type or the same type of rubber as the rubber component of the rubber composition of the compressed rubber layer is often used. The ratio of additives such as a vulcanizing agent or a crosslinking agent, a co-crosslinking agent or a crosslinking aid, and a vulcanization accelerator can also be selected from the same range as that of the rubber composition of the compressed rubber layer. The rubber composition of the adhesive rubber layer may further contain an adhesion improver (resorcin-formaldehyde cocondensate, amino resin, etc.).

  The thickness of the adhesive rubber layer is, for example, about 0.4 to 3.0 mm, preferably about 0.6 to 2.2 mm, and more preferably about 0.8 to 1.4 mm.

(Core)
The core wires are embedded in the belt body so as to extend in the longitudinal direction of the belt. Usually, a plurality of core wires are embedded in parallel at a predetermined pitch parallel to the longitudinal direction of the belt. The distance (spinning pitch) is, for example, about 0.5 to 3 mm, preferably about 0.8 to 1.5 mm, and more preferably about 1 to 1.3 mm.

  As the core wire, a twisted cord using multifilament yarn (for example, various twists, single twists, rung twists, etc.) can be used. The average wire diameter (fiber diameter of the twisted cord) of the core wire is, for example, about 0.5 to 3 mm, preferably about 0.6 to 2 mm, and more preferably about 0.7 to 1.5 mm.

Examples of fibers constituting the core wire include natural fibers (cotton, hemp, etc.), regenerated fibers (rayon, acetate, etc.), synthetic fibers (polyolefin fibers such as polyethylene and polypropylene, styrene fibers such as polystyrene, polyfluoroethylene, etc. Fluorine fibers such as acrylic fibers, vinyl alcohol fibers such as polyvinyl alcohol, polyamide fibers, polyester fibers, wholly aromatic polyester fibers, aramid fibers, etc.), inorganic fibers (carbon fibers, glass fibers, etc.), etc. . Among the fibers, from the viewpoint of high modulus, synthesis of polyester fibers (polyalkylene arylate fibers) mainly composed of C _2-4 alkylene arylates such as ethylene terephthalate and ethylene-2,6-naphthalate, aramid fibers, etc. Inorganic fibers such as fibers and carbon fibers are widely used, and polyester fibers [polyethylene terephthalate fibers (PET fibers), polyethylene naphthalate fibers (PEN fibers), polytrimethylene terephthalate fibers (PTT fibers)], and aramid fibers are preferable. . Since the polyester fiber is contracted by heat, it is excellent in belt tension maintenance. On the other hand, since the aramid fiber has a higher tensile strength than the polyester fiber, it can compensate for a part that cannot be realized by the polyester fiber with respect to the demand for high tension and high load.

  The fiber may be a multifilament yarn. The fineness of the multifilament yarn may be, for example, about 2000 to 10000 denier (particularly 4000 to 8000 denier).

  In order to improve the adhesion to rubber, the core wire may be subjected to an adhesion treatment. In the adhesion treatment, generally, the fibers can be immersed in a resorcin-formalin-latex liquid (RFL liquid) and then dried by heating to form a uniform adhesive layer on the surface. In addition to this adhesion treatment, the core fiber is pretreated with a conventional adhesive component, for example, an epoxy compound (epoxy resin, etc.), a reactive compound (adhesive compound) such as an isocyanate compound, and then RFL. You may process with a liquid. The RFL liquid is a composition in which an initial condensate (prepolymer) of resorcin and formalin is mixed with latex. Examples of the latex include chloroprene, styrene-butadiene-vinylpyridine terpolymer, hydrogenated nitrile rubber (H-NBR), and NBR.

(Stretch layer)
(1) Stretched rubber layer When the frictional power transmission belt is formed of a stretched rubber layer like the belt shown in FIG. 1, the stretched rubber layer has the same rubber composition (ethylene-α) as the compressed rubber layer. -A rubber composition containing a rubber component such as an olefin elastomer) can be used. In the rubber composition of the stretch rubber layer, as the rubber component, the same type or type of rubber as the rubber component of the rubber composition of the compressed rubber layer is often used. The ratio of additives such as a vulcanizing agent or a crosslinking agent, a co-crosslinking agent or a crosslinking aid, and a vulcanization accelerator can also be selected from the same range as that of the rubber composition of the compressed rubber layer.

  The stretch rubber layer may further contain a short fiber in order to suppress abnormal noise generated by the adhesion of the back rubber when the back surface is driven. As a short fiber, the fiber similar to the fiber illustrated by the term of the said core wire can be used. These short fibers can be used alone or in combination of two or more. Among these fibers, cellulose fibers such as cotton and rayon, polyester fibers (PET fibers, etc.), polyamide fibers (aliphatic polyamide fibers such as polyamide 6, aramid fibers, etc.) are widely used.

  The short fibers may be treated with a conventional adhesion treatment (or surface treatment), for example, resorcin-formalin-latex (RFL) solution, in order to improve dispersibility and adhesion in the rubber composition.

  The average fiber length of the short fibers may be, for example, about 1 to 20 mm, preferably 2 to 15 mm, and more preferably about 3 to 10 mm. The average fiber diameter of the short fibers is, for example, about 5 to 50 μm, preferably 7 to 40 μm, and more preferably about 10 to 30 μm. The ratio of the short fiber is, for example, 1 to 50 parts by mass, preferably 5 to 40 parts by mass, and more preferably about 10 to 35 parts by mass with respect to 100 parts by mass of the rubber component.

  The orientation direction of the short fibers in the stretched rubber layer is not particularly limited, and may be oriented in a random direction or in a predetermined direction such as a belt direction. Among these, it is preferable to orient in random directions from the viewpoint that the generation of cracks and cracks from multiple directions can be suppressed. Furthermore, when short fibers (for example, milled fibers) having a bent portion as the short fibers are oriented in random directions, resistance can be expressed against forces acting from more directions. Further, as shown in FIG. 1, when the adhesive rubber layer is not formed, the core wire is embedded in the belt body at the boundary region between the stretch rubber layer and the compression rubber layer, so that the adhesion between the core wire and the belt body is improved. In consideration, either one of the stretched rubber layer and the compressed rubber layer (particularly the compressed rubber layer) is preferably composed of a rubber composition not containing short fibers.

  Furthermore, an uneven pattern may be provided on the surface of the stretched rubber layer (the back surface of the belt) in order to suppress noise during back-side driving. Examples of the concavo-convex pattern include a knitted fabric pattern, a woven fabric pattern, and a suede woven fabric pattern. Of these patterns, fabric patterns are preferred.

  The thickness of the stretched rubber layer is, for example, about 0.8 to 10.0 mm, preferably 1.2 to 6.5 mm, and more preferably about 1.6 to 5.2 mm.

(2) Stretch layer formed of fabric (reinforcement fabric) When the stretch layer is formed of fabric (reinforcement fabric) as in the friction transmission belt shown in FIG. Cloth materials such as woven fabric, wide-angle canvas, knitted fabric, and non-woven fabric. Among these, a woven fabric woven in the form of plain weave, twill weave, satin weave, or a wide angle canvas or knitted fabric in which the crossing angle between the warp and the weft is about 90 to 120 ° is preferable.

  As the fibers constituting the reinforcing cloth, the same fibers as the short fibers can be used. The reinforcing cloth may be treated with the resorcin-formalin-latex liquid (RFL liquid) (immersion process or the like) and then friction coated or rubbed with the rubber composition to form a rubber canvas.

[Method of manufacturing friction transmission belt]
The manufacturing method of the friction transmission belt of the present invention includes a core spinning process for winding a core wire around a cylindrical drum, and a compressed rubber layer for winding an unvulcanized rubber sheet for forming a compressed rubber layer on the wound core wire A winding step, a skin layer winding step of winding a fabric formed of thermoplastic resin fibers on the wound unvulcanized rubber sheet, an unvulcanized (uncrosslinked) rubber sheet in which the core wire and the fabric are wound Is vulcanized (or cross-linked) and pressed onto a mold (pressed with a mold), and the fabric is melted on the surface of the resulting compressed rubber layer to form a skin layer having a film-like portion It is a method including a forming step and is not particularly limited as long as it is a method of forming with a mold without polishing, and a conventional method can be used for steps other than the skin layer winding step.

  Specifically, in the production method of the present invention, as a pre-process of the core spinning step, a stretch layer (rubber sheet including short fibers) is formed on a flexible jacket (blader) mounted on a cylindrical forming drum. Alternatively, a step of winding a member constituting the reinforcing fabric) and, if necessary, a rubber sheet forming an adhesive rubber layer may be included, and the core wire may be further spirally spun on the wound member.

  In the compressed rubber layer winding step, a rubber sheet for forming a compressed rubber layer (rib rubber layer) is usually wound on the core wire spun in the step.

  Furthermore, in the present invention, in the skin layer winding step, a fabric (for example, a nonwoven fabric) formed of thermoplastic resin fibers having a melting point that melts at the vulcanization temperature of the belt on the surface of the rubber sheet for forming the rib rubber layer. Wrap. In the skin layer winding step, as described above, the fabric is preferably wound in a plurality of layers.

  The fabric is preferably wound in an oblique direction with respect to the circumferential direction of the cylindrical forming drum. Specifically, the angle between the joint portion (overlap portion) of the fabric to be wound and the circumferential direction of the cylindrical forming drum is, for example, 10 to 80 °, preferably 20 to 70 °, more preferably 30 to 60. It is preferable to wrap the fabric so that the angle is about 40 ° (particularly 40 to 50 °). By winding the fabric in an oblique direction, it is possible to suppress the generation of abnormal noise during traveling even when a slight level difference occurs after the fabric melts.

  In the vulcanization molding step, for example, 120 to 200 ° C. (especially 150 to 180 ° C.) while inflating the flexible jacket and pressing the unvulcanized sleeve against an outer mold having a groove-shaped mark corresponding to the rib portion. ) Vulcanization molding at a temperature of about. At this time, on the surface of the rib portion, the fabric melts at the vulcanization temperature, and a film-like skin layer having a uniform thickness with no steps is formed.

  In this way, a vulcanized sleeve having the rib portion formed is obtained, and then the individual vulcanized sleeve (V-ribbed belt or the like) can be finished by cutting the vulcanized sleeve into a predetermined width and cutting.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. In the following examples, measurement methods or evaluation methods for each physical property, and raw materials used in the examples are shown below. Unless otherwise specified, “part” and “%” are based on mass.

(1) Appearance of rib part surface The produced V-ribbed belt was cut in the belt width direction, and the cross-section was photographed with a microscope to observe the melted state and average thickness of the skin layer.

(2) Pronunciation resistance The pronunciation resistance was evaluated by a misalignment pronunciation test. The testing machine used for the evaluation was configured by arranging a driving pulley (diameter 120 mm), a driven pulley (diameter 120 mm), and a tension pulley (diameter 70 mm), and an angle of 1.86 ° between the driving pulley and the driven pulley. Misalignment was set. Then, a V-ribbed belt was suspended between the pulleys, and the drive pulley was run at 1000 rpm under room temperature conditions. At this time, a load was applied to the driving pulley so that the belt tension was 6 kgf / rib, and a load of 2.1 Nm / rib was applied to the driven pulley. The sound generation level when the V-ribbed belt was run in this way was evaluated in the following five levels. “5” indicates a state where the sound generation level is the lowest, and “3” or higher is a level at which sound generation is not a concern. This sound resistance test was performed under two conditions: dry (DRY) and water injection (WET) at 60 ml / min.

5: I cannot hear the pronunciation at all. 4: I can hear the pronunciation with the stethoscope. 3: I can hear the sound a little. 2: I can hear the pronunciation. 1: I can hear the pronunciation clearly.

(3) Friction property In the friction test, a V-ribbed belt is cut to a predetermined length, and the V-ribbed belt is hung on a guide roller (diameter 60 mm) so that the winding angle is 90 °, and one end of the V-ribbed belt is fixed. At the same time, the weight of 1.75 kgf / rib is suspended at the other end and the guide roller is rotated at 43 rpm. By detecting the value of the load cell at this time, the tension side of the one end of the V-ribbed belt is The tension T ₁ and the tension T ₂ on the loose side at the other end are measured, and the friction coefficient (μ = (1 / 2π) ln (T ₁ / T ₂ )) from the tension ratio (T ₁ / T ₂ ) Asked. This friction test was also performed under two conditions: dry (DRY) and water injection (WET) at 60 ml / min.

(4) Heat resistance durability The driving tester used for the heat resistance durability test has a drive pulley (diameter 120 mm), an idler pulley (diameter 85 mm), a driven pulley (diameter 120 mm), and a tension pulley (diameter 45 mm). Composed. Then, a V-ribbed belt is suspended on each pulley so that the winding angle around the tension pulley is 90 ° and the winding angle around the idler pulley is 120 °. Was run. At this time, a load was applied to the drive pulley so that the belt tension was 40 kgf / rib, and a load of 8.8 kW was applied to the driven pulley. Then, the V-ribbed belt was allowed to run for 400 hours, and the time until six cracks reaching the core line were measured was measured.

(5) Raw material EPDM polymer: “IP3640” manufactured by DuPont Dowelasmer Japan Co., Ltd., Mooney viscosity 40 (100 ° C.)
Carbon HAF: “Seast 3” manufactured by Tokai Carbon Co., Ltd.
Anti-aging agent: “Nonflex OD3” manufactured by Seiko Chemical Co., Ltd.
Nylon milled fiber: nylon 66, fiber length approx. 0.5mm
Organic peroxide: “Parkadox 14RP” manufactured by Kayaku Akzo Corporation
Ether S plasticizer: “RS-700” manufactured by Adeka Co., Ltd., SP value 8.5, viscosity 30 cps (20 ° C.)
Solid lubricant: artificial graphite powder “AT No. 20”, average particle size 8 μm
LDPE non-woven fabric: low density polyethylene fiber, “Stratex LL” manufactured by Idemitsu Unitech Co., Ltd., melting point about 110 ° C.
PP non-woven fabric: polypropylene fiber, “WJ55P100” manufactured by Venus Paper Co., Ltd., melting point of about 165 ° C.
TPO non-woven fabric: Olefin elastomer fiber, “Straflex” manufactured by Idemitsu Unitech Co., Ltd., melting point approx.
PP / LDPE non-woven fabric: core-sheath conjugate fiber having a core part made of polypropylene and a sheath part made of low-density polyethylene, melting point of about 165 ° C.
PET nonwoven fabric: “Hybon” manufactured by Shinwa Co., Ltd., melting point 260 ° C.
Nylon nonwoven fabric: “NIACE” manufactured by Unitika Ltd., melting point 250 ° C.
Core wire: A fiber obtained by bonding a cord of total denier 6,000, which is a 2 × 3 twisted configuration of 1,000 denier PET fiber and twisted with an upper twist factor of 3.0 and a lower twist factor of 3.0.

Examples 1 to 4 and Comparative Example 1
(Rubber sheet for forming the stretched rubber layer)
The rubber composition shown in Table 1 was kneaded with a Banbury mixer and rolled with a calender roll to prepare a rubber sheet with a thickness of 0.8 mm for forming an extension layer.

(Rubber sheet for forming a compressed rubber layer)
The rubber composition shown in Table 2 was kneaded with a Banbury mixer and rolled with a calender roll to prepare a rubber sheet with a thickness of 2.5 mm for forming a compressed rubber layer.

(Manufacture of belts)
As shown in FIG. 3, a rubber sheet 16a for forming an elastic rubber layer is wound around the outer periphery of a bladder 15 of a mold 14 having an air supply port 23 and a top plate 22a. After winding the core wire 4 in a spiral shape, a rubber sheet 16b for forming a compressed rubber layer was further wound around the core wire 4. Further, using the nonwoven fabric shown in Table 3 on the outer peripheral surface of the rubber sheet 16b, the joint portion is wound a predetermined number of times at an angle of about 45 ° with respect to the belt circumferential direction, and the belt is wound around the mold 14 A sleeve 17 was attached.

  Further, as shown in FIG. 4, the mold 14 around which the belt sleeve 17 is wound is set in the vulcanizing mold 18 and heated by a heating / cooling jacket 35 having heating / cooling medium introduction ports 36, 37. As shown in FIG. 5, the bladder 15 was expanded and vulcanized by pressing the belt sleeve 17 against the inner peripheral surface of the vulcanizing mold 18 and applying pressure. The vulcanization conditions were set at 160 ° C., 1 MPa, and 20 minutes. At this time, the concave / convex portion 41 for molding of the vulcanizing mold 18 bites into the belt sleeve 17 from the outer periphery, so that the groove 26 was formed on the outer periphery of the belt sleeve 17.

  Next, the mold 14 was extracted from the vulcanization mold 18, and the vulcanization belt sleeve remaining in the vulcanization mold 18 was cooled by the heating / cooling jacket 35, and then the vulcanization belt sleeve was removed from the vulcanization mold 18. And this V-ribbed belt of the structure shown in FIG. 1 was obtained by cut | disconnecting this vulcanization belt sleeve so that it might cut with a cutter. On the surface of the rib portion of the obtained V-ribbed belt, the low melting point fiber of the nonwoven fabric was completely melted at the vulcanization temperature, and a film-like skin layer having a solid and uniform thickness was formed. The microscope photograph of the rib part cross section of the V-ribbed belt obtained in Example 1 is shown in FIG. As is clear from FIG. 6, a skin layer having a uniform thickness (a uniform and thin layer formed of three layers of LDPE nonwoven fabric) was formed on the surface of the rib portion of the V-ribbed belt of Example 1.

(Evaluation of belt)
Table 4 shows the evaluation of the appearance, sound resistance, friction and heat durability of the rib portion surface of the manufactured V-ribbed belt.

  As is clear from the results in Table 4, the belts of the examples have good sound resistance and heat resistance, whereas the belts of the comparative examples maintain the nonwoven fabric state. A level difference occurred at the joint, and an abnormal noise was generated due to the level difference.

  The friction transmission belt of the present invention can be used for various mold molding-less belts, for example, a friction transmission belt such as a V-ribbed belt, a low-edge V-belt, a flat belt, and the like. Useful for ribbed belts, V-belts and the like.

DESCRIPTION OF SYMBOLS 1 ... V-ribbed belt 2 ... Adhesive rubber layer 3 ... Core wire 4 ... Short fiber 5 ... Stretch layer 6 ... Compression rubber layer 7 ... Rib part 8 ... Skin layer

Claims (9)

A friction transmission belt comprising at least a core wire and a compressed rubber layer for engaging or contacting with a pulley, wherein the surface of the compressed rubber layer has a melting point or a softening point below the vulcanization temperature of the compressed rubber layer. The thermoplastic resin fiber is a melt of a cloth formed of a thermoplastic resin fiber and is covered with a skin layer that is a film having no fiber structure, and the thermoplastic resin forming the thermoplastic resin fiber is crosslinked. Not a friction transmission belt.   2. The friction transmission belt according to claim 1, wherein the thermoplastic resin forming the thermoplastic resin fiber is at least one selected from an olefin resin and a thermoplastic elastomer. The friction transmission belt according to claim 1 or 2 , wherein the fabric is a non-woven fabric. The friction transmission belt according to any one of claims 1 to 3 , wherein the skin layer has an average thickness of 0.01 to 0.5 mm. The friction transmission belt according to any one of claims 1 to 4 , which is a friction transmission V belt or a friction transmission V ribbed belt. A core spinning process for winding a core wire around a cylindrical drum, a compressed rubber layer winding step for winding an unvulcanized rubber sheet for forming a compressed rubber layer on the wound core wire, a wound unvulcanized rubber sheet Further, a skin layer winding step of winding a fabric formed of thermoplastic resin fibers, pressing the unvulcanized rubber sheet wrapped with the core wire and the fabric against a mold, vulcanizing and molding, and obtaining the compression The friction transmission belt according to any one of claims 1 to 5 , further comprising a vulcanization forming step of forming a skin layer which is a melt of the fabric and has a fiber shape on the surface of the rubber layer. Manufacturing method. The manufacturing method according to claim 6 , wherein in the skin layer winding step, a plurality of layers of the fabric are wound in layers. The manufacturing method according to claim 6 or 7 , wherein in the skin layer winding step, the fabric is wound in an oblique direction with respect to the circumferential direction of the cylindrical drum. The process according to any one fabric of claims 6-8 spunbond nonwoven having a basis weight of 15 to 80 g / ^{m 2.}