JP2018004080A - Friction transmission belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a friction transmission belt capable of improving the sliding property without damaging the abrasion resistance, the side pressure resistance, and durability.SOLUTION: The friction transmission surface of a compression rubber layer in the friction transmission belt is formed by vulcanizate of the rubber composition containing a rubber constituent and graphene. The graphene contains about 0.1-10 pts.mass to 100 pts.mass of the rubber constituent. The average particle size of the graphene is about 0.1-3 μm. The compression rubber layer may further contain short fibers. The short fibers may orient in a belt width direction. The short fibers may contain 30 pts. mass or less to 100 pts. mass of the rubber constituent. The rubber constituent may also be chloroprene rubber. A friction transmission belt of the invention may also be a low edge cogged V belt.SELECTED DRAWING: None

Description

  The present invention relates to a friction transmission belt in which a friction transmission surface such as a V-belt or a V-ribbed belt is inclined in a V shape and transmits power via a frictional force generated between a pulley and a belt side surface.

  The friction transmission belt transmits power through a frictional force generated between the pulley and the side surface of the belt. As the friction coefficient between the pulley and the belt side surface is larger, the frictional force becomes larger, which is advantageous in terms of power transmission. However, if the friction coefficient becomes too high, the force required for the belt to come out of the pulley becomes large, so that it becomes difficult for the belt to come out of the pulley. As a result, the belt is bent in the vicinity of the pulley outlet, which causes heat generation and noise. In particular, in a belt used for motorcycle speed change, shifting is performed by moving the belt between pulleys in the pulley radial direction. When the friction coefficient of the belt side surface increases, the belt moves in the pulley radial direction. This causes a lot of transmission loss and also reduces fuel efficiency. Various means for reducing the friction coefficient have been proposed for these problems, but since the side pressure resistance of the belt can be improved in addition to the reduction of the friction coefficient, the compression rubber layer In general, a method of blending short fibers has been widely used.

  However, short fibers not only reduce the friction coefficient but also improve the lateral pressure resistance of the belt. On the other hand, short fibers become the starting point of cracks generated in the rubber and reduce the durability of the belt.

  In Japanese Utility Model Publication No. 7-31006 (Patent Document 1), a rubber power transmission belt having a V-shaped compression portion, short fibers projectingly embedded in the side wall surface of the V-shaped compression portion, and talc, There is disclosed a power transmission belt in which a powdery viscosity inhibitor selected from calcium carbonate, clay, and silica is attached so as to embed a protruding portion of the short fiber.

  However, when powder is applied to the side surface of the belt, although the friction coefficient can be reduced in the initial stage of running, the powder is scattered over time, and the effect is lost early. In addition, when the powder is applied excessively, the frictional force is reduced more than necessary, and the power transmission function may be impaired.

  Japanese Patent Application Laid-Open No. 2007-232205 (Patent Document 2) discloses that the friction transmission surface is 10 to 25 parts by weight of a plasticizer such as a petroleum plasticizer and carbon black with respect to 100 parts by weight of an ethylene / α-olefin elastomer. A friction transmission belt composed of a rubber composition containing 60 to 110 parts by weight of an inorganic filler is disclosed. This document describes that an appropriate friction coefficient can be maintained by a bleed plasticizer by adding a plasticizer to the rubber composition.

  However, when a plasticizer is added to the rubber composition, the effect of reducing the coefficient of friction is exhibited for a relatively long time, but the plasticizer still bleeds mainly from the vicinity of the belt surface. After a certain period, the plasticizer bleed is reduced. Also, the amount of plasticizer bleed is greatly affected by temperature conditions, and depending on the conditions, the expected amount does not bleed and the friction coefficient does not decrease much, or conversely, excessive bleed causes friction more than necessary. The coefficient decreases. In addition, in order to reduce the friction coefficient, it is necessary to add a relatively large amount of plasticizer. However, if a large amount of plasticizer is added, the physical properties of the rubber will deteriorate, and the side pressure resistance and durability of the belt will decrease. Cause a decline.

  JP-A-2005-15769 (Patent Document 3) includes 10 to 50 parts by mass of polyamide short fibers and 10 to 100 parts by mass of a solid lubricant with respect to 100 parts by mass of a raw rubber such as an ethylene / α-olefin elastomer. A transmission belt having a blended compressed rubber layer is disclosed. This document describes that the friction coefficient of a rubber composition is reduced by using graphite, molybdenum disulfide, polytetrafluoroethylene (PTFE), or the like as the solid lubricant.

  However, when a solid lubricant is added to the rubber composition, the effect of reducing the friction coefficient is exhibited over a long period of time, but a large amount of the solid lubricant is required to exhibit a sufficient effect of reducing the friction coefficient. Need to be added. If too much solid lubricant is added, the processability of the rubber will decrease, the elongation of the rubber will decrease and the bending fatigue resistance will decrease, or the crack will occur in the rubber and the durability will decrease. .

Japanese Utility Model Publication No. 7-31006 (Scope of request for registration of utility model) JP 2007-232205 A (claim, paragraph [0046]) JP 2005-15769 A (Claims, paragraph [0024])

  An object of the present invention is to provide a friction transmission belt capable of improving slidability without impairing wear resistance, side pressure resistance (rigidity) and durability.

  Another object of the present invention is to provide a friction transmission belt that can improve sound resistance and fuel efficiency without impairing durability even under severe conditions in a high load environment such as a transmission belt.

  As a result of diligent studies to achieve the above-mentioned problems, the present inventor has formed a friction transmission surface of a compression rubber layer in a friction transmission belt with a rubber composition and a vulcanized product of a rubber composition containing graphene, thereby providing wear resistance. The present invention has been completed by finding that the slidability can be improved without impairing the properties, side pressure resistance and durability.

  That is, the friction transmission belt of the present invention is a friction transmission belt provided with a compression rubber layer having a friction transmission surface at least partially in contact with the pulley, and the friction transmission surface of the compression rubber layer includes a rubber component and It is formed of a vulcanized rubber composition containing graphenes. The ratio of the graphenes is about 0.1 to 10 parts by mass with respect to 100 parts by mass of the rubber component. The average particle size of the graphenes is about 0.1 to 3 μm. The compressed rubber layer may further contain short fibers. The short fibers may be oriented in the belt width direction. The proportion of the short fibers may be 30 parts by mass or less with respect to 100 parts by mass of the rubber component. The ratio of the graphenes is 0.5 to 5 parts by mass with respect to 100 parts by mass of the rubber component, and the compressed rubber layer may further contain a solid lubricant and / or a friction modifier. The ratio of the graphenes is about 1 to 50 parts by mass with respect to 100 parts by mass in total of the solid lubricant and the friction modifier. The rubber component may be chloroprene rubber. The friction transmission belt of the present invention may be a low edge cogged V belt.

  In the present invention, since the friction transmission surface of the compression rubber layer in the friction transmission belt is formed of a vulcanized product of a rubber composition containing a rubber component and graphenes, the wear resistance, side pressure resistance and durability are impaired. Therefore, slidability can be improved. In particular, heat generation and noise can be reduced by reducing the friction coefficient of the friction transmission surface, and transmission loss can be reduced. Therefore, sound resistance and fuel saving can be improved without impairing durability even under severe conditions in a high load environment such as a transmission belt.

FIG. 1 is a schematic perspective view showing an example of the friction transmission belt of the present invention. FIG. 2 is a schematic sectional view of the friction transmission belt of FIG. 1 cut in the belt longitudinal direction. FIG. 3 is a schematic diagram for explaining a durability running test of the friction transmission belt in the embodiment.

[Structure of friction transmission belt]
As the friction transmission belt of the present invention, it is sufficient that the friction transmission surface of the compression rubber layer contains a rubber component and graphene, and a conventional friction transmission belt can be used. Examples of the friction transmission belt of the present invention include a V belt [a wrapped V belt, a low edge V belt, a low edge cogged V belt (a low edge cogged V belt having a cog formed on the inner peripheral side of the low edge belt, Low edge double cogged V belt in which cogs are formed on both the circumferential side and the outer circumferential side)], V-ribbed belt, flat belt, and the like. Among these friction transmission belts, a V belt or a V-ribbed belt in which the friction transmission surface is inclined in a V shape (at a V angle) is preferable from the viewpoint of receiving a large lateral pressure from the pulley. The low edge cogged V belt is particularly preferable because it is used in a belt-type continuously variable transmission that requires a high degree of compatibility between durability and fuel saving.

  FIG. 1 is a schematic perspective view showing an example of a friction transmission belt (low edge cogged V belt) according to the present invention, and FIG. 2 is a schematic sectional view of the friction transmission belt of FIG. 1 cut in the longitudinal direction of the belt.

  In this example, the friction transmission belt 1 has a plurality of cog portions 1a formed at predetermined intervals along the longitudinal direction of the belt on the inner peripheral surface of the belt main body. The cross-sectional shape in the longitudinal direction (A direction in the figure) is substantially semicircular (curved or corrugated), and the cross-sectional shape in the direction orthogonal to the longitudinal direction (width direction or B direction in the figure) is a table. Shape. That is, each cog 1a protrudes from the cog bottom 1b in a cross section in the A direction in a substantially semicircular shape in the belt thickness direction. The friction transmission belt 1 has a laminated structure, and the reinforcing cloth 2, the stretch rubber layer 3, the adhesive rubber layer 4, and the compression from the belt outer peripheral side toward the inner peripheral side (side where the cog portion 1 a is formed). A rubber layer 5 and a reinforcing cloth 6 are sequentially laminated. The cross-sectional shape in the belt width direction is a trapezoidal shape in which the belt width decreases from the belt outer peripheral side toward the inner peripheral side. Furthermore, a core body 4a is embedded in the adhesive rubber layer 4, and the cog 1a is formed on the compressed rubber layer 5 by a cog-molding mold.

[Compressed rubber layer]
In the present invention, the friction transmission surface of the compression rubber layer is formed of a vulcanized product of a rubber composition containing a rubber component and graphenes. Therefore, graphenes are present on at least a part of the friction transmission surface of the compression rubber layer. The friction coefficient of the friction transmission surface can be reduced (slidability can be improved). The compression rubber layer only needs to have a friction transmission surface formed of the rubber composition. For example, a surface layer portion formed of a rubber composition containing graphenes is formed on the friction transmission surface, and another portion (inner layer) is formed. Part) may be a compressed rubber layer that does not contain graphenes, but from the viewpoint of productivity and the like, a compressed rubber layer in which the entire compressed rubber layer is formed of a rubber composition containing graphenes is preferable.

(Graphenes)
The graphenes include a graphene sheet that is a single sheet usually referred to as “graphene” and a graphene film (multilayer graphene) that is a laminate of the graphene sheets.

The graphene sheet is a material constituting graphite, and is a sheet (single layer sheet) of sp ² bonded carbon atoms having a thickness of 1 atom. The structure has a hexagonal lattice structure (honeycomb structure) like a honeycomb formed from carbon atoms and their bonds.

  The graphene film is obtained by exfoliating graphite, is a thin laminate compared with graphite, and has a crystal structure. The number of stacked graphene films is, for example, about 2 to 20, and preferably about 3 to 10.

  The aspect ratio (average diameter / average thickness of the plate surface) of the graphene film may be 20 or more, for example, about 20 to 100,000, preferably about 50 to 30,000, and more preferably about 100 to 10,000. The average thickness of the graphene film may be, for example, about 1 to 10 nm, preferably about 1.5 to 5 nm.

  The graphenes may contain graphene oxide or may be formed of only graphene oxide.

  The shape of the graphenes is not particularly limited, and examples thereof include a sheet shape, a granular shape (powdered shape or an indeterminate shape), a combined shape of a sheet shape and a granular shape, and the like. Of these shapes, granular is preferable because it is easy to handle and easily disperses uniformly in the resin component.

  When the graphenes are granular, the average particle diameter of the graphenes may be 50 μm or less, for example, 0.01 to 50 μm, preferably 0.03 to 10 μm, more preferably 0.05 to 5 μm (particularly 0. 1 to 3 μm). If the average particle size is too small, it may be scattered when blended with the rubber component and the handleability may be reduced. If it is too large, agglomerates are easily formed in the rubber component, and it is difficult to disperse uniformly. There is a risk of becoming.

  In the present specification and claims, the average particle diameter of graphenes was observed with a scanning electron microscope (“JSM-5900LV” manufactured by JEOL Ltd.) at a magnification of 5000 times, and was randomly selected. The particle diameter of each particle can be measured and averaged.

  Graphenes can be produced by a conventional method, and may be produced, for example, by a method described in Japanese Patent No. 5688669, Japanese Patent No. 5697067, Japanese Patent Application Laid-Open No. 2015-501873, WO2013 / 146213.

  The ratio of graphene can be selected from the range of about 0.1 to 15 parts by mass (for example, 0.1 to 10 parts by mass) with respect to 100 parts by mass of the rubber component, for example, 0.2 to 10 parts by mass, preferably 0. About 3 to 8 parts by mass, more preferably about 0.5 to 5 parts by mass (particularly 0.8 to 3 parts by mass).

  When the rubber composition contains short fibers, the proportion of graphene is, for example, 0.5 to 100 parts by mass, preferably 1 to 50 parts by mass, and more preferably 3 to 40 parts by mass with respect to 100 parts by mass of the short fibers. (Especially 5 to 30 parts by mass). When the rubber composition contains a conventional solid lubricant and / or a friction modifier, the ratio of the graphenes is, for example, 1 to 50 parts by mass, preferably 100 parts by mass with respect to a total of 100 parts by mass of the solid lubricant and the friction modifier. Is about 1.5 to 30 parts by mass, more preferably about 2 to 20 parts by mass (particularly 3 to 15 parts by mass).

  If the ratio of the graphenes is too small, the effect of reducing the friction coefficient may be reduced.If the ratio is too large, the friction coefficient becomes too low and the belt slips, resulting in fuel saving. There is a possibility that the durability is lowered, and there is a possibility that the durability is lowered due to heat generated by the slip. In addition, the ratio of these graphenes is formed by the surface layer part and other parts (inner layer part) formed by the rubber composition containing the rubber component and the graphenes in which the compressed rubber layer is formed on the friction transmission surface. The ratio of the rubber composition forming the surface layer portion.

(Short fiber)
In the present invention, the rubber composition forming the friction transmission surface may not contain short fibers, but preferably further contains short fibers in addition to the graphenes. By blending short fibers in a rubber composition that forms a compressed rubber layer that receives a large amount of side pressure and frictional force from the pulley, the side pressure resistance of the friction transmission belt can be secured by preferably orienting the short fibers in the belt width direction. . On the other hand, from the viewpoint of the durability of the belt, it is preferable that the ratio of the short fibers is the minimum necessary to ensure the side pressure resistance. In the present invention, since the proportion of short fibers can be adjusted to the minimum necessary due to the presence of graphenes, the bending rigidity of the belt can be kept small while maintaining the side pressure resistance. Therefore, both the coefficient of friction (improvement of slidability) and bending rigidity (improvement of flexibility) can be reduced, and the transmission loss is small and fuel saving can be ensured. That is, when short fibers and graphenes are used in combination, the side pressure resistance and fuel economy (both flexibility and slidability) can be improved.

Examples of short fibers include polyolefin fibers (polyethylene fibers, polypropylene fibers, etc.), polyamide fibers (polyamide 6 fibers, polyamide 66 fibers, polyamide 46 fibers, aramid fibers, etc.), polyalkylene arylate fibers (polyethylene terephthalate (PET)). Fiber, poly C _2-4 alkylene C _6-14 arylate fiber such as polyethylene naphthalate (PEN) fiber, etc.], vinylon fiber, polyvinyl alcohol fiber, synthetic fiber such as polyparaphenylene benzobisoxazole (PBO) fiber; Natural fibers such as cotton, hemp and wool; inorganic fibers such as carbon fibers are widely used. These short fibers can be used alone or in combination of two or more. Among these short fibers, synthetic fibers and natural fibers, particularly synthetic fibers (polyamide fibers, polyalkylene arylate fibers, etc.), among others, are rigid and have high strength and modulus, and at least from the point that they tend to protrude on the surface of the compressed rubber layer. Short fibers including aramid fibers are preferred. Aramid short fibers also have high wear resistance. Aramid fibers are commercially available, for example, under the trade names “Conex”, “Nomex”, “Kevlar”, “Technola”, “Twaron”, and the like.

  The short fibers are oriented in the belt width direction and embedded in the compressed rubber layer in order to suppress the compression deformation of the belt against the pressure from the pulley. Further, by causing the short fibers to protrude from the surface of the compressed rubber layer, it is possible to reduce the friction coefficient of the surface to suppress noise (sound generation) and to reduce wear due to rubbing with the pulley. The average length of the short fibers may be, for example, about 1 to 20 mm, preferably about 1.2 to 15 mm (for example, 1.5 to 10 mm), more preferably about 2 to 5 mm (particularly 2.5 to 4 mm). If the average length of the short fibers is too short, the mechanical properties (for example, the modulus) in the direction of preparation may not be sufficiently improved. Conversely, if the length is too long, the short fibers in the rubber composition may be poorly dispersed. As a result, the rubber may crack and the belt may be damaged early.

  The average protruding height of the short fibers in the entire friction transmission surface may be 50 μm or more, for example, about 50 to 200 μm, preferably 60 to 180 μm, and more preferably about 70 to 160 μm (particularly 80 to 150 μm). If the average protrusion height is too small, the friction coefficient of the surface may not be sufficiently reduced. Conversely, if the average protrusion height is too large, breakage or dropout is likely to occur. The average protruding height is obtained by, for example, observing a cross section cut in the belt width direction with an electron microscope or the like, and a plurality of short fibers protruding from the belt side surface (projecting height) (for example, 10 to 1000, preferably 30 to 500, more preferably 50 to 200, particularly about 100), and these can be calculated by averaging.

  The average fiber diameter of the short fibers is, for example, about 1 to 100 μm, preferably 3 to 50 μm, more preferably about 5 to 30 μm (particularly 10 to 20 μm). If the average fiber diameter is too large, the mechanical properties of the compressed rubber layer may be reduced, and if it is too small, the surface friction coefficient may not be sufficiently reduced.

  The shape of the short fiber in the protruding portion is not particularly limited, the shape protruding substantially perpendicularly from the side surface, the shape curled in one direction (for example, the polishing direction), the shape fibrillated at the tip, and melted by the heat during polishing It may be a shape such as a flowering shape. Furthermore, the shape described in JP-A-7-98044 and JP-A-7-151191 may be used.

  In the present invention, the ratio of short fibers can be suppressed to a small amount by combining with graphenes present on the friction transmission surface, so that the bending rigidity of the belt can be reduced and the transmission efficiency of the belt can be improved. The proportion of the short fibers may be 50 parts by mass or less (for example, 40 parts by mass or less, preferably 30 parts by mass or less) with respect to 100 parts by mass of the rubber component, for example, 10-25 parts by mass, preferably 12-23. It may be about 15 to 20 parts by mass, and more preferably about 10 to 20 parts by mass (particularly 12 to 18 parts by mass). If the proportion of short fibers is too small, the mechanical properties of the compressed rubber layer may be reduced. On the other hand, if the amount is too large, in addition to the decrease in transmission efficiency, the dispersibility of the short fiber in the rubber composition is reduced, resulting in poor dispersion, and cracks may occur in the compressed rubber layer at an early stage starting from that location. There is also. In applications where durability is important, the proportion of short fibers may be 20 parts by mass or less (for example, 0 to 20 parts by mass), for example, 15 parts by mass or less (100 parts by mass (for example). For example, 0 to 10 parts by mass), preferably 5 parts by mass or less (for example, 0 to 3 parts by mass), more preferably about 1 part by mass or less (0 to 0.5 parts by mass), and substantially shorter. It does not have to contain fibers.

  From the viewpoint of dispersibility and adhesiveness of the short fibers in the rubber composition, at least the short fibers are preferably subjected to an adhesion treatment (or surface treatment). In addition, it is not necessary for all the short fibers to be subjected to the adhesion treatment, and the short fibers subjected to the adhesion treatment and the short fibers not subjected to the adhesion treatment (untreated short fibers) may be mixed or used together.

  In the short fiber adhesion treatment, various adhesion treatments, for example, treatment solutions containing an initial condensate of phenols and formalin (such as a prepolymer of a novolak or resol type phenol resin), treatment solutions containing a rubber component (or latex). , Treatment with a treatment liquid containing the initial condensate and a rubber component (latex), a silane coupling agent, an epoxy compound (epoxy resin, etc.), a treatment liquid containing a reactive compound (adhesive compound) such as an isocyanate compound, etc. be able to. In a preferred adhesion treatment, the short fibers are treated with a treatment liquid containing the precondensate and a rubber component (latex), particularly at least a resorcin-formalin-latex (RFL) liquid. Such treatment liquids may be used in combination. For example, short fibers may be pre-treated with a conventional adhesive component such as an epoxy compound (epoxy resin or the like) or a reactive compound (adhesive compound) such as an isocyanate compound. After processing, you may process with RFL liquid.

  When treated with such a treatment liquid, particularly an RFL liquid, the short fiber and the rubber component can be strongly bonded. The RFL liquid is a mixture of an initial condensate of resorcin and formaldehyde and a rubber latex. The molar ratio of resorcin to formaldehyde is within a range where the adhesion between the rubber component and the short fiber can be improved, for example, the former / the latter = 1 / 0.5 to 1/3, preferably 1 / 0.6 to 1/2. 0.5, more preferably about 1 / 0.7 to 1 / 1.5, even if it is about 1 / 0.5 to 1/1 (eg 1 / 0.6 to 1 / 0.8) Good. The type of latex is not particularly limited, and can be appropriately selected from rubber components described later according to the type of rubber component to be bonded. For example, when the rubber component to be bonded is mainly composed of chloroprene rubber, the latex is diene rubber (natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber, styrene-butadiene rubber (SBR), styrene-butadiene-vinyl. Pyridine terpolymer, acrylonitrile-butadiene rubber (nitrile rubber), hydrogenated nitrile rubber, etc.), ethylene-α-olefin elastomer, chlorosulfonated polyethylene rubber, alkylated chlorosulfonated polyethylene rubber and the like may be used. These latexes may be used alone or in combination of two or more. Preferred latexes are diene rubbers (styrene-butadiene-vinylpyridine terpolymers, chloroprene rubber, butadiene rubber, etc.), chlorosulfonated polyethylene rubbers, and styrene-butadiene-vinylpyridine for further improving the adhesion. Ternary copolymers are preferred. When the short fibers are bonded with a treatment liquid (RFL liquid or the like) containing at least a styrene-butadiene-vinylpyridine terpolymer, the adhesion between the rubber composition (chloroprene rubber composition or the like) and the short fibers can be improved.

  The ratio of the initial condensate of resorcin and formalin may be about 10 to 100 parts by mass (for example, 12 to 50 parts by mass, preferably 15 to 30 parts by mass) with respect to 100 parts by mass of the rubber component of the latex. In addition, the total solid content concentration of RFL liquid can be adjusted in the range of 5-40 mass%.

  The adhesion rate of the adhesive component (solid content) to the short fibers is, for example, 1 to 25% by mass, preferably 3 to 20% by mass, more preferably 5 to 15% by mass, and 3 to 10% by mass (particularly 4 to 8%). % By mass). If the adhesion rate of the adhesive component is too small, the dispersibility of the short fiber in the rubber composition and the adhesive property between the short fiber and the rubber composition are insufficient. May be firmly fixed, and on the contrary, dispersibility may be reduced.

  The method for preparing the bonded short fibers is not particularly limited. For example, a method in which multifilament long fibers are impregnated in a bonding treatment liquid and dried to be cut to a predetermined length, or an untreated short fiber is bonded to a bonding processing solution. For example, a method of immersing the substrate in a predetermined time, and then removing the excess bonding treatment liquid by a method such as centrifugation, followed by drying can be used.

(Rubber component)
Examples of the rubber component include known vulcanizable or crosslinkable rubber components and / or elastomers such as diene rubbers (for example, natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber (CR), styrene-butadiene rubber (SBR)). Diene rubbers such as vinyl pyridine-styrene-butadiene copolymer rubber, acrylonitrile-butadiene rubber (nitrile rubber); hydrogenated nitrile rubber (including mixed polymer of hydrogenated nitrile rubber and unsaturated carboxylic acid metal salt) Hydrogenated products, etc.], olefin rubber [eg, ethylene-α-olefin rubber (ethylene-α-olefin elastomer), polyoctenylene rubber, ethylene-vinyl acetate copolymer rubber, chlorosulfonated polyethylene rubber, alkyl Chlorosulfonated polyethylene rubber, etc.] Examples thereof include epichlorohydrin rubber, acrylic rubber, silicone rubber, urethane rubber, and fluorine rubber. These rubber components can be used alone or in combination of two or more.

  Among these rubber components, an ethylene-α-olefin elastomer (ethylene-propylene copolymer (EPM), ethylene-propylene-diene terpolymer ( Ethylene-α-olefin rubbers such as EPDM) and chloroprene rubber are widely used, especially when used in high load environments such as transmission belts, mechanical strength, weather resistance, heat resistance, cold resistance, oil resistance, adhesion, etc. From the viewpoint of excellent balance, chloroprene rubber and EPDM are preferable. Furthermore, chloroprene rubber is particularly preferable from the viewpoint of excellent wear resistance in addition to the above characteristics. The chloroprene rubber may be a sulfur-modified type or a non-sulfur-modified type.

  When the rubber component contains chloroprene rubber, the proportion of the chloroprene rubber in the rubber component may be about 50% by mass or more (particularly 80 to 100% by mass), and 100% by mass (chloroprene rubber only) is particularly preferable.

(Solid lubricant and / or friction modifier)
The rubber composition may further contain a conventional solid lubricant and / or friction modifier. In the present invention, by combining graphenes with a conventional solid lubricant and / or friction modifier, the friction coefficient of the friction transmission surface can be reduced without reducing the durability of the belt.

  Examples of conventional solid lubricants include graphite, fluororesins (such as polytetrafluoroethylene), molybdenum disulfide, and ultrahigh molecular weight polyethylene. These solid lubricants can be used alone or in combination of two or more. As friction modifiers, inorganic powders such as calcium carbonate, calcium phosphate, potassium titanate, aluminum borate, alumina, silica, mica, talc (hydrous magnesium silicate), iron powder, titanium oxide, pyrophyllite ( And waxy clay). These friction modifiers can be used alone or in combination of two or more.

  Of these, solid lubricants such as graphite, fluororesin, and ultrahigh molecular weight polyethylene are preferred.

  The total ratio of the solid lubricant and the friction modifier may be 50 parts by mass or less with respect to 100 parts by mass of the rubber component, for example, 1 to 50 parts by mass, preferably 3 to 40 parts by mass, and more preferably 5 to 5 parts by mass. It is about 30 parts by mass (particularly 10 to 20 parts by mass). If the ratio of the solid lubricant and the friction modifier is too large, the belt durability may be reduced.

(Additive)
The rubber composition may include a vulcanizing agent or a crosslinking agent (or a crosslinking agent system), a co-crosslinking agent, a vulcanization aid, a vulcanization accelerator, a vulcanization retarder, a metal oxide (for example, oxidation) Zinc, magnesium oxide, calcium oxide, barium oxide, iron oxide, copper oxide, etc.), reinforcing agents (carbon black, etc.), fillers, softeners (oils such as paraffin oil and naphthenic oil), processing agents or processing Auxiliaries (fatty acids such as stearic acid, fatty acid metal salts such as stearic acid metal salts, fatty acid amides such as stearic acid amide, wax, paraffin, etc.), anti-aging agents (antioxidants, thermal anti-aging agents, anti-bending cracks) Agents, ozone deterioration inhibitors, etc.), colorants, tackifiers, plasticizers, lubricants, coupling agents (silane coupling agents, etc.), stabilizers (UV absorbers, heat stabilizers, etc.), flame retardants It may contain an antistatic agent. The metal oxide may act as a crosslinking agent.

  As the vulcanizing agent or the crosslinking agent, conventional components can be used depending on the type of rubber component. For example, the metal oxide (magnesium oxide, zinc oxide, etc.), organic peroxide (diacyl peroxide, peroxyester) And dialkyl peroxide), sulfur vulcanizing agents, and the like. Examples of the sulfur-based vulcanizing agent include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, sulfur chloride (sulfur monochloride, sulfur dichloride, etc.), and the like. These crosslinking agents or vulcanizing agents may be used alone or in combination of two or more. When the rubber component is chloroprene rubber, a metal oxide (magnesium oxide, zinc oxide, etc.) may be used as a vulcanizing agent or a crosslinking agent. The metal oxide may be used in combination with other vulcanizing agents (such as sulfur-based vulcanizing agents), and the metal oxide and / or sulfur-based vulcanizing agent may be used alone or in combination with a vulcanization accelerator. May be used.

  The proportion of the vulcanizing agent can be selected from a range of about 1 to 20 parts by mass with respect to 100 parts by mass of the rubber component depending on the types of the vulcanizing agent and the rubber component. For example, the ratio of the organic peroxide as the vulcanizing agent is 1 to 8 parts by weight, preferably 1.5 to 5 parts by weight, and more preferably about 2 to 4.5 parts by weight with respect to 100 parts by weight of the rubber component. The ratio of the metal oxide is 1 to 20 parts by weight, preferably 3 to 17 parts by weight, more preferably 5 to 15 parts by weight (particularly 7 to 13 parts by weight) based on 100 parts by weight of the rubber component. ) Select from a range of degrees.

  Examples of the co-crosslinking agent (crosslinking aid or co-vulcanizing agent co-agent) include known crosslinking aids such as polyfunctional (iso) cyanurates [for example, triallyl isocyanurate (TAIC), triallyl cyanurate ( TAC)], polydienes (for example, 1,2-polybutadiene, etc.), metal salts of unsaturated carboxylic acids [for example, zinc (meth) acrylate, magnesium (meth) acrylate, etc.], oximes (for example, quinone di) Oximes), guanidines (eg, diphenylguanidine, di-tolylguanidine, etc.), polyfunctional (meth) acrylates [eg, ethylene glycol di (meth) acrylate, butanediol di (meth) acrylate, trimethylolpropane tri ( Meth) acrylates, etc.], bismaleimides (aliphatic bismaleimide, eg For example, N, N′-1,2-ethylenedimaleimide, 1,6′-bismaleimide- (2,2,4-trimethyl) cyclohexane and the like; arene bismaleimide or aromatic bismaleimide such as N, N ′ -M-phenylene dimaleimide, 4-methyl-1,3-phenylene dimaleimide, 4,4'-diphenylmethane dimaleimide, 2,2-bis [4- (4-maleimidophenoxy) phenyl] propane, 4,4 ' -Diphenyl ether dimaleimide, 4,4'-diphenylsulfone dimaleimide, 1,3-bis (3-maleimidophenoxy) benzene and the like. These crosslinking aids can be used alone or in combination of two or more. Of these crosslinking aids, bismaleimides (arene bismaleimides such as N, N′-m-phenylene dimaleimide or aromatic bismaleimides) are preferable. The addition of bismaleimides can increase the degree of crosslinking and prevent adhesive wear and the like.

  The ratio of the co-crosslinking agent (crosslinking aid) can be selected from the range of about 0.01 to 10 parts by mass, for example, 0.1 to 10 parts by mass (for example, 0), in terms of solid content, with respect to 100 parts by mass of the rubber component. .3-8 parts by mass), preferably about 0.5-6 parts by mass (especially 1-5 parts by mass).

  Examples of the vulcanization accelerator include thiuram accelerators [for example, tetramethylthiuram monosulfide (TMTM), tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), tetrabutylthiuram disulfide (TBTD). ), Dipentamethylene thiuram tetrasulfide (DPTT), N, N′-dimethyl-N, N′-diphenyl thiuram disulfide, etc.], thiazole-based accelerators [for example, 2-mercaptobenzothiazol, 2 -Zinc salts of mercaptobenzothiazol, 2-mercaptothiazoline, dibenzothiazyl disulfide, 2- (4'-morpholinodithio) benzothiazole, etc.], sulfenamide accelerators [for example, N-cyclohexyl-2 -Benzothiazylsulfene Bromide (CBS), N, etc. N'- dicyclohexyl-2-benzothiazyl sulfenamide, urea or thiourea-based accelerators (e.g., such as ethylene thiourea), dithiocarbamates, and the like xanthates is. These vulcanization accelerators can be used alone or in combination of two or more. Of these vulcanization accelerators, TMTD, DPTT, CBS and the like are widely used.

  The proportion of the vulcanization accelerator is, for example, 0.1 to 15 parts by mass, preferably 0.3 to 10 parts by mass, and more preferably 0.5 to 5 parts by mass in terms of solid content with respect to 100 parts by mass of the rubber component. It may be about a part.

  The ratio of the reinforcing agent (carbon black, silica, etc.) is about 10 to 100 parts by mass (preferably 20 to 80 parts by mass, more preferably 30 to 70 parts by mass) with respect to 100 parts by mass of the total amount of rubber components. Also good. The ratio of the softening agent (oils such as naphthenic oil) is, for example, 1 to 30 parts by mass, preferably 3 to 20 parts by mass (for example, 5 to 10 parts by mass) with respect to 100 parts by mass of the total amount of rubber components. It may be a degree. Moreover, the ratio of a processing agent or a processing aid (stearic acid etc.) is 10 mass parts or less (for example, 0-10 mass parts) with respect to 100 mass parts of rubber components, Preferably 0.1-5 mass parts, More preferably, it may be about 0.3 to 3 parts by mass (particularly 0.5 to 2 parts by mass). Furthermore, the ratio of the antioxidant is, for example, 0.5 to 15 parts by mass, preferably 1 to 10 parts by mass, and more preferably 2.5 to 7.5 parts by mass (100 parts by mass of the total amount of rubber components). In particular, it may be about 3 to 7 parts by mass).

[Stretch rubber layer]
The stretched rubber layer may be formed of a vulcanized rubber composition containing the rubber component exemplified in the compressed rubber layer, and may contain graphenes and short fibers in the same manner as the compressed rubber layer. Further, the stretched rubber layer may be a layer formed of the same vulcanized rubber composition as the compressed rubber layer except for graphenes.

[Adhesive rubber layer]
The rubber composition for forming the adhesive rubber layer is a metal component such as a rubber component (chloroprene rubber, etc.), a vulcanizing agent or a cross-linking agent (magnesium oxide, zinc oxide, etc.), like the vulcanized rubber composition of the compressed rubber layer. Products, sulfur-based vulcanizing agents such as sulfur), co-crosslinking agents or crosslinking aids (such as maleimide-based crosslinking agents such as N, N'-m-phenylene dimaleimide), vulcanization accelerators (TMTD, DPTT, CBS) Etc.), enhancer (carbon black, silica etc.), softener (oils such as naphthenic oil), processing agent or processing aid (stearic acid, metal stearate, wax, paraffin etc.), anti-aging agent, Adhesion improver [resorcin-formaldehyde co-condensate, amino resin (condensate of nitrogen-containing cyclic compound and formaldehyde such as hexamethylol melamine, hexaa Melamine resins such as lucoxymethyl melamine (hexamethoxymethyl melamine, hexabutoxymethyl melamine, etc.), urea resins such as methylol urea, benzoguanamine resins such as methylol benzoguanamine resin), and co-condensates thereof (resorcin-melamine-formaldehyde co Condensates, etc.), fillers (clay, calcium carbonate, talc, mica, etc.), colorants, tackifiers, plasticizers, coupling agents (silane coupling agents, etc.), stabilizers (ultraviolet absorbers, heat Stabilizers, etc.), flame retardants, antistatic agents and the like. In the adhesion improver, the resorcin-formaldehyde cocondensate and amino resin may be an initial condensate (prepolymer) of nitrogen-containing cyclic compound such as resorcin and / or melamine and formaldehyde.

  In this rubber composition, a rubber of the same type (diene rubber or the like) or the same type (chloroprene rubber or the like) as the rubber component of the rubber composition of the compressed rubber layer is often used as the rubber component. Further, the amounts of the vulcanizing agent or crosslinking agent, co-crosslinking agent or crosslinking aid, vulcanization accelerator, enhancer, softener and anti-aging agent are each in the same range as the rubber composition of the compressed rubber layer. You can choose from. Moreover, in the rubber composition of the adhesive rubber layer, the ratio of the processing agent or processing aid (such as stearic acid) is 0.1 to 10 parts by mass, preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the rubber component. Part, more preferably about 1 to 3 parts by mass. Further, the ratio of the adhesion improver (resorcin-formaldehyde cocondensate, hexamethoxymethylmelamine, etc.) is 0.1 to 20 parts by mass, preferably 1 to 10 parts by mass, more preferably 100 parts by mass of the rubber component. 2-8 mass parts may be sufficient. Furthermore, graphenes may or may not be contained in the same proportion as the rubber composition of the compressed rubber layer.

[Core]
Although it does not specifically limit as a core, Usually, the core wire (twisted cord) arranged at predetermined intervals in the belt width direction can be used. The cores are arranged to extend in the longitudinal direction of the belt, and are usually arranged to extend in parallel at a predetermined pitch in parallel with the longitudinal direction of the belt. The core wire only needs to be at least partially in contact with the adhesive rubber layer. The adhesive rubber layer embeds the core wire, the core wire embeds between the adhesive rubber layer and the stretch rubber layer, and the adhesive rubber. Any form of embedding a core wire between the layer and the compressed rubber layer may be employed. Among these, the form in which the adhesive rubber layer embeds the core wire is preferable from the viewpoint that durability can be improved.

Examples of the fibers constituting the core wire include the same fibers as the short fibers. Among the fibers, polyester fiber (polyalkylene arylate fiber) mainly composed of C _2-4 alkylene C _6-14 arylate such as ethylene terephthalate and ethylene-2,6-naphthalate from the point of high modulus, polyamide Synthetic fibers such as fibers (such as aramid fibers), inorganic fibers such as carbon fibers, etc. are widely used, and polyester fibers (polyethylene terephthalate fibers, polyethylene naphthalate fibers) and polyamide fibers are preferred. 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). The multifilament yarn may include, for example, 100 to 5,000, preferably 500 to 4,000, and more preferably about 1,000 to 3,000 monofilament yarns.

  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 may be, for example, 0.5 to 3 mm, preferably 0.6 to 2 mm, and more preferably about 0.7 to 1.5 mm. Good.

  The core wire may be subjected to adhesion treatment (or surface treatment) in the same manner as the short fiber in order to improve adhesion with the rubber component. Similarly to the short fiber, the core wire is preferably subjected to adhesion treatment with at least the RFL solution.

[Reinforcing cloth]
When a reinforcing cloth is used in the friction transmission belt, the reinforcing cloth is not limited to a form in which the reinforcing cloth is laminated on the surface of the compressed rubber layer. For example, the reinforcing cloth is applied to the surface of the stretched rubber layer (the surface opposite to the adhesive rubber layer). It may be laminated, or a form in which a reinforcing layer is embedded in a compressed rubber layer and / or a stretched rubber layer (for example, a form described in JP 2010-230146 A). The reinforcing cloth can be formed of, for example, a cloth material (preferably a woven cloth) such as a woven cloth, a wide angle sail cloth, a knitted cloth, and a non-woven cloth. If necessary, the above-described adhesion treatment, for example, treatment with an RFL solution (immersion treatment) Or the like, or after the adhesive rubber and the cloth material are laminated, they may be laminated on the surface of the compression rubber layer and / or the stretch rubber layer.

[Method of manufacturing friction transmission belt]
The manufacturing method of the friction transmission belt of the present invention is not particularly limited, and a conventional method can be used for the lamination process of each layer (the manufacturing method of the belt sleeve).

  For example, in the case of a cogged V belt, a laminated body composed of a reinforcing cloth (under cloth) and a sheet for a compressed rubber layer (unvulcanized rubber) is arranged with teeth and grooves alternately with the reinforcing cloth down. Installed on a flat cogged mold, cog pad with the cog part formed by press-pressing at a temperature of about 60-100 ° C (especially 70-80 ° C) (not completely vulcanized, in a semi-cured state) After producing a certain pad), both ends of the cog pad may be cut vertically from the top of the cog crest. Furthermore, an inner mother die in which teeth and grooves are alternately arranged is covered on a cylindrical mold, and a cog pad is wound around the teeth and the grooves, and a joint is formed at the top of the cog crest, and this is wound. After laminating the first adhesive rubber layer sheet (lower adhesive rubber: unvulcanized rubber) on the cog pad, the core is spun in a spiral shape, and the second adhesive rubber layer sheet (upper adhesive) Rubber: Same as the adhesive rubber layer sheet), a stretch rubber layer sheet (unvulcanized rubber), and a reinforcing cloth (upper cloth) may be wound in order to produce a molded body. After that, a jacket is put on and the mold is placed in a vulcanizing can, and vulcanized at a temperature of about 120 to 200 ° C. (especially 150 to 180 ° C.) to prepare a belt sleeve. Cutting may be performed.

  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, the raw materials used in the examples and the measurement methods or evaluation methods for each physical property are shown below. Unless otherwise specified, “part” and “%” are based on mass.

[material]
Chloroprene rubber: Denka Co., Ltd. “Denka Chloroprene DCR”
Aramid short fiber: “Conex short fiber” manufactured by Teijin Techno Products Limited, average fiber length 3 mm, average fiber diameter 14 μm
Vinylpyridine-styrene-butadiene copolymer latex: Nippon Zeon Co., Ltd. Graphene: Graphene Platform Co., Ltd. “GNH-X1”
Graphite: “AT-20” manufactured by Oriental Sangyo Co., Ltd.
Ultra high molecular weight polyethylene (UHMW-PE): “GUR-4150” manufactured by Ticona Engineering Polymers
Unfired low molecular weight PTFE: “KTL-8F” manufactured by Kitamura Co., Ltd.
Plasticizer: manufactured by DIC Corporation, sebacate oil Carbon black: “Seast 3” manufactured by Tokai Carbon Co., Ltd.
Silica: “Nipsil VN3” manufactured by Tosoh Silica Corporation
Anti-aging agent: “Nonflex OD3” manufactured by Seiko Chemical Co., Ltd.
Core wire: A twisted cord obtained by adhering a cord of total denier 6,000, in which 1,000 denier PET fibers are twisted in a 2 × 3 configuration with an upper twist coefficient of 3.0 and a lower twist coefficient of 3.0.

[Friction coefficient and wear amount]
The rubber compositions for compressed rubber layers of Examples and Comparative Examples were vulcanized at 153 ° C. for 30 minutes to prepare test pieces having a width of 10 mm, a length of 20 mm, and a thickness of 4 mm. A sliding friction and wear tester that can push the mating material attached to the lower base to the test piece attached to the upper part with a constant surface pressure and reciprocate the test piece attached to the upper part at a constant speed (( The test was conducted under the conditions of a speed of 10 m / min, a surface pressure of 0.5 MPa, a temperature of 70 ° C., and a running time of 20 hours. The material of the mating material was SUS304. For the friction coefficient, the load cell voltage was sampled every 10 seconds, and an average value for a test time of 20 hours was calculated. The amount of wear was determined by measuring the weight loss of the test piece before and after the test.

[Durability test (side pressure resistance)]
As shown in FIG. 3, the endurance running test was performed using a two-axis running test machine including a driving (Dr.) pulley 12 having a diameter of 50 mm and a driven (Dn.) Pulley 13 having a diameter of 125 mm. A low-edge cogged V-belt 11 is hung on each pulley 12 and 13, the drive pulley 12 is rotated at 5000 rpm, a load of 10 N · m is applied to the driven pulley 13, and the belt 11 is kept at an ambient temperature of 80 ° C. for a maximum of 40 hours. I drove it. The belt surface temperature during running reached a maximum of 120 ° C. The side surface of the cog portion of the low edge cogged V-belt 11 after running is visually observed, and the crack generation ratio per 100 cog portions (the ratio of the number of cog portions where cracks originated from short fibers) are calculated, Evaluation was made according to the following criteria.

◎: 0% crack generation
○: Crack generation exceeds 0% and less than 10% ×: Crack generation is 10% or more.

Examples 1-10 and Comparative Examples 1-5
(Formation of rubber layer)
The rubber compositions in Table 1 (adhesive rubber layer) and Table 2 (compressed rubber layer and stretched rubber layer) were each kneaded using a known method such as a Banbury mixer, and the kneaded rubber was passed through a calender roll. Rolled rubber sheets (adhesive rubber layer sheet, compression rubber layer sheet, stretch rubber layer sheet). The short fibers were bonded with an RFL solution (containing resorcin and formaldehyde and vinylpyridine-styrene-butadiene rubber latex as a latex), and short fibers having a solid content of 6 mass% were used. As the RFL liquid, 2.6 parts by mass of resorcin, 1.4 parts by mass of 37% formalin, 17.2 parts by mass of vinylpyridine-styrene-butadiene copolymer latex, and 78.8 parts by mass of water were used.

(Manufacture of friction transmission belt)
The laminated body of the reinforcing cloth that becomes the lower cloth and the sheet for the compressed rubber layer (unvulcanized rubber) is installed in a flat cogged mold in which the teeth and grooves are alternately arranged with the reinforcing cloth facing down, A cog pad (not completely vulcanized but in a semi-vulcanized state) with a cog part formed by press-pressing at 75 ° C. was produced. Next, both ends of the cog pad were cut vertically from the top of the cog crest.

  Cover the inner die with teeth and grooves alternately on a cylindrical mold, engage the teeth and grooves, wrap the cog pad, joint at the top of the cog crest, and wind this cog pad After laminating a sheet for an adhesive rubber layer (lower adhesive rubber: unvulcanized rubber) on top, the core wire is spun into a spiral shape, and an adhesive rubber layer sheet (upper adhesive rubber: for the adhesive rubber layer) The same as the sheet), a stretched rubber layer sheet (unvulcanized rubber), and a reinforcing cloth (upper cloth) serving as an upper cloth were sequentially wound to prepare a molded body. Thereafter, the jacket was put on and the mold was placed in a vulcanizing can and vulcanized at a temperature of 160 ° C. for 20 minutes to obtain a belt sleeve. This sleeve is cut into a V-shaped cross-sectional shape with a predetermined width in the longitudinal direction of the belt with a cutter, and further polished on both sides of the belt to form a belt having a structure shown in FIG. 1, that is, a transmission belt having cogs on the inner peripheral side of the belt. A low edge cogged V-belt (size: upper width 22.0 mm, thickness 11.0 mm, outer peripheral length 800 mm) was produced.

  The measurement results of the friction coefficient and the wear amount of the rubber composition for the compressed rubber layer are shown in Table 2, and the results of the durability running test of the obtained friction transmission belt are also shown in Table 2.

  In Comparative Example 1 not containing graphene and solid lubricant, the friction coefficient was high, and many cracks occurred in the durability running test. It is thought that because the friction coefficient is high, the pulley does not come out of the pulley and is bent backward, the heat generation increases, and the heat causes the rubber to cure and deteriorate.

  In Examples 1 to 3 containing graphene, the friction coefficient was sufficiently reduced, and the amount of wear was also small. Further, no cracks occurred in the durability running test. In particular, since a large effect can be obtained with a small amount of addition as in Examples 1 and 2, the possibility of becoming a starting point of a crack can be suppressed without greatly affecting the processability and physical properties of rubber. It is done.

  In Example 4 in which 10 parts by mass of graphene was blended, the friction coefficient was greatly reduced and the amount of wear was the smallest. However, it is considered that cracks occurred in a small amount in the endurance running test, slip occurred due to the friction coefficient falling to an appropriate value or more, and the rubber was thermally deteriorated.

  Comparative Examples 2 and 3 are belts using graphite as a solid lubricant. However, when added in a small amount, the effect of lowering the friction coefficient is hardly expressed, and even when blended in a large amount, the graphene is blended. A sufficient decrease in the coefficient of friction was not observed, and cracks occurred. Graphite has a structure in which multiple layers of graphene are stacked, so the inner layer cannot exert any effect, and even if the same weight is added, it is considered that the effect is less likely to be obtained than graphene. Comparative Example 4 is a belt in which ultra high molecular weight polyethylene is blended, but a sufficient friction coefficient reducing effect was not seen as in the case of graphite. Comparative Example 5 is a belt in which ultra high molecular weight polyethylene is used in combination with graphite, but a sufficient friction coefficient reducing effect was not found in the same manner.

  Example 5 uses graphene with graphite, Example 6 uses graphene with ultrahigh molecular weight polyethylene, Example 7 uses unfired low molecular weight PTFE, Example 8 uses graphene, ultrahigh molecular weight polyethylene, unfired low Although it was a belt in which three types of molecular weight PTFE were blended, the friction coefficient could be further reduced as compared with the case of using graphene alone without inhibiting each other. Thus, it is also possible to obtain a target friction coefficient by changing various mixing ratios of the solid lubricant.

  Example 9 is a belt that does not include short fibers and includes 1 part by mass of graphene with respect to 100 parts by mass of chloroprene rubber. Compared with Example 1 containing both graphene and short fibers, the coefficient of friction was slightly larger, but no cracks occurred in the durability running test.

  Example 10 is a belt including 40 parts by mass of short fibers and 1 part by mass of graphene with respect to 100 parts by mass of chloroprene rubber. Compared with Example 1 containing 15 parts by mass of short fibers, the friction coefficient was small and the amount of wear was small, but a small amount of cracks occurred in the durability running test. This is presumably because the bending fatigue resistance decreased as the amount of short fibers added increased.

  From the results of Examples 1 and 9 to 10, by adding graphene, high abrasion resistance, lateral pressure resistance and slidability are exhibited even if the proportion of short fibers is small or contains no short fibers. It was found that the characteristics can be improved in a well-balanced manner.

  The friction transmission belt of the present invention can be applied to, for example, a V belt (wrapped V belt, low edge V belt, low edge cogged V belt), V ribbed belt, flat belt, and the like. In particular, a V-belt (transmission belt) used in a transmission (continuously variable transmission) in which the gear ratio changes steplessly during belt travel, such as a motorcycle, an ATV (four-wheel buggy), a snowmobile, etc. The present invention is preferably applied to a low edge cogged V belt and a low edge double cogged V belt used in a transmission.

DESCRIPTION OF SYMBOLS 1 ... Friction power transmission belt 2, 6 ... Reinforcement cloth 3 ... Stretch rubber layer 4 ... Adhesive rubber layer 4a ... Core body 5 ... Compression rubber layer

Claims (10)

  A friction transmission belt comprising a compression rubber layer having a friction transmission surface at least partially in contact with a pulley, wherein the friction transmission surface of the compression rubber layer is a vulcanization of a rubber composition containing a rubber component and graphenes A friction transmission belt formed of objects.   The friction transmission belt according to claim 1, wherein the proportion of graphene is 0.1 to 10 parts by mass with respect to 100 parts by mass of the rubber component.   The friction transmission belt according to claim 1 or 2, wherein the graphene has an average particle size of 0.1 to 3 µm.   The friction transmission belt according to any one of claims 1 to 3, wherein the compressed rubber layer further includes short fibers.   The friction transmission belt according to claim 4, wherein the short fibers are oriented in the belt width direction.   The friction transmission belt according to claim 4 or 5, wherein the proportion of short fibers is 30 parts by mass or less with respect to 100 parts by mass of the rubber component.   The ratio of graphene is 0.5-5 mass parts with respect to 100 mass parts of rubber components, and a compression rubber layer further contains a solid lubricant and / or a friction modifier. Friction transmission belt.   The friction transmission belt according to claim 7, wherein a ratio of the graphene is 1 to 50 parts by mass with respect to 100 parts by mass in total of the solid lubricant and the friction modifier.   The friction transmission belt according to any one of claims 1 to 8, wherein the rubber component is chloroprene rubber. The friction transmission belt according to any one of claims 1 to 9, which is a low-edge cogged V-belt.

Images