JP6227843B1 - Transmission belt - Google Patents

Abstract

The transmission belt (B) has a back rubber layer (11) on the belt outer peripheral side. The back rubber layer (11) is formed of a rubber composition mainly composed of an ethylene-propylene-diene terpolymer having an ethylene content of 60% by mass or more and a diene content of 1% by mass or less.

Description

  The present invention relates to a transmission belt.

  A power transmission belt having a back rubber layer formed of a rubber composition comprising an ethylene-propylene-diene terpolymer (hereinafter referred to as “EPDM”) as a rubber component is known. For example, Patent Document 1 discloses a V-ribbed belt having a back rubber layer formed of a rubber composition of EPDM having a diene content of 0.2 to 7.5% by mass.

JP 2013-177967 A

  The present invention relates to a power transmission belt having a back rubber layer on the outer peripheral side of the belt, wherein the back rubber layer comprises EPDM having an ethylene content of 60% by mass or more and a diene content of 1% by mass or less as a main rubber component. Formed of a rubber composition.

3 is a perspective view of a V-ribbed belt according to Embodiment 1. FIG. 3 is a cross-sectional view of one V-rib of the V-ribbed belt according to Embodiment 1. FIG. It is a longitudinal cross-sectional view of a belt shaping | molding die. It is a longitudinal cross-sectional enlarged view of a part of belt forming die. FIG. 5 is a first explanatory view of the method for manufacturing the V-ribbed belt according to the first embodiment. FIG. 6 is a second explanatory diagram of the method for manufacturing the V-ribbed belt according to the first embodiment. FIG. 6 is a third explanatory diagram of the method for manufacturing the V-ribbed belt according to the first embodiment. FIG. 10 is a fourth explanatory diagram of the method for manufacturing the V-ribbed belt according to the first embodiment. It is a figure which shows the pulley layout of the auxiliary machine drive belt transmission of a motor vehicle. 6 is a perspective view of a V-ribbed belt according to Embodiment 2. FIG. 6 is a cross-sectional view of one V-rib of the V-ribbed belt according to Embodiment 2. FIG. 6 is a first explanatory view of a method for manufacturing a V-ribbed belt according to Embodiment 2. FIG. FIG. 10 is a second explanatory diagram of the method for manufacturing the V-ribbed belt according to the second embodiment. It is a perspective view of the low edge type V belt concerning other embodiments. It is a perspective view of the toothed belt which concerns on other embodiment. It is a figure which shows the pulley layout of a belt running test machine.

  Hereinafter, embodiments will be described in detail based on the drawings.

(Embodiment 1)
1 and 2 show a V-ribbed belt B (power transmission belt) according to the first embodiment. The V-ribbed belt B according to the first embodiment is, for example, an endless belt used for an auxiliary machine driving belt transmission provided in an engine room of an automobile. The V-ribbed belt B according to Embodiment 1 has, for example, a belt length of 700 to 3000 mm, a belt width of 10 to 36 mm, and a belt thickness of 4.0 to 5.0 mm.

  The V-ribbed belt B according to the first embodiment is formed of a triple layer including a back rubber layer 11 on the belt outer peripheral side, an intermediate adhesive rubber layer 12 and a compression rubber layer 13 constituting a surface rubber layer on the belt inner peripheral side. A ribbed belt body 10 is provided. A core wire 14 is embedded in an intermediate portion in the thickness direction of the adhesive rubber layer 12 of the V-ribbed belt body 10 so as to form a spiral having a pitch in the belt width direction. The thickness of the back rubber layer 11 is, for example, 0.4 to 0.8 mm. The thickness of the adhesive rubber layer 12 is, for example, 1.0 to 2.5 mm. The thickness of the compressed rubber layer 13 is, for example, 1.0 to 3.6 mm.

  The back rubber layer 11 is configured in a strip shape having a horizontally long cross section. The surface of the back rubber layer 11, that is, the back surface of the belt, is preferably formed in a form in which the texture of the woven fabric is transferred from the viewpoint of suppressing sound generated between the flat rubber and the contacting flat pulley.

  The back rubber layer 11 is formed of a rubber composition in which a rubber component is crosslinked by heating and pressurizing an uncrosslinked rubber composition in which various compounding agents are blended with a rubber component. Therefore, the rubber composition forming the back rubber layer 11 contains a crosslinked rubber component and various compounding agents.

  The rubber component of the rubber composition forming the back rubber layer 11 contains EPDM as a main component. The content of EPDM in the rubber component is 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 100% by mass. In addition to EPDM, the rubber component includes ethylene-α-olefin elastomers other than EPDM (for example, ethylene-propylene copolymer (EPR), ethylene-octene copolymer, ethylene-butene copolymer, etc.), chloroprene rubber (CR), chlorosulfonated Polyethylene rubber (CSM), hydrogenated acrylonitrile rubber (H-NOR) and the like may be included.

  The EPDM contained in the rubber component of the rubber composition forming the back rubber layer 11 has an ethylene content (A) of 60% by mass or more and a diene content (B) of 1% by mass or less. According to the V-ribbed belt B according to Embodiment 1, the back rubber layer 11 is formed of a rubber composition mainly composed of EPDM having an ethylene content of 60% by mass or more and a diene content of 1% by mass or less. Therefore, as shown in the examples described later, adhesive wear of the back rubber layer 11 can be suppressed.

  The ethylene content (A) of this EPDM is preferably 65% by mass or more, more preferably 68% by mass or more, and preferably 86% by mass or less, more preferably 76% by mass from the viewpoint of suppressing adhesive wear. It is as follows. The ethylene content is measured based on ASTM D3900 (the same applies hereinafter).

  The diene content (B) of this EPDM is greater than 0, but is preferably 0.1% by mass or more, more preferably 0.4% by mass or more, and preferably 1% from the viewpoint of suppressing adhesive wear. 0.7% by mass or less, more preferably 1.1% by mass or less. The diene content is measured based on ASTM D6047 (the same applies hereinafter).

  Examples of the diene component include ethylidene nobornene (ENB), dicyclopentadiene, 1,4-hexadiene, and the like. Among these, the diene component is preferably ethylidene nobornene.

Mooney viscosity at 125 ° C. The EPDM, from the viewpoint of suppressing the adhesive wear, preferably _20ML 1 + 4 (125 ℃) or more, more preferably _35ML 1 + 4 (125 ℃) or more, and preferably _70ML 1 + 4 (125 ℃ ) Or less, more preferably 55 ML _{1 + 4} (125 ° C.) or less. Mooney viscosity is measured based on ASTM D1646 (and so on).

  Examples of the compounding agent include reinforcing materials such as carbon black, fillers, softeners, anti-aging agents, processing aids, vulcanization aids, cross-linking agents, and co-crosslinking agents.

  As carbon black, for example, channel black; furnace black such as SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, N-234; FT, MT, etc. Thermal black; acetylene black and the like. Silica is also mentioned as the reinforcing material. The reinforcing material preferably contains one or more of these. The reinforcing material preferably contains ISAF or FEF. Content of a reinforcing material is 30-70 mass parts with respect to 100 mass parts of rubber components of a rubber composition.

  Examples of the filler include magnesium carbonate, calcium carbonate, layered silicate, and the like. One or both of these are preferably used as the filler, and magnesium carbonate is more preferably used. The content of the filler is preferably 5 to 20 parts by mass, more preferably 5 to 15 parts by mass with respect to 100 parts by mass of the rubber component.

  Examples of the softener include petroleum-based softeners; mineral oil-based softeners such as paraffin wax; castor oil, cottonseed oil, sesame oil, rapeseed oil, soybean oil, palm oil, palm oil, peanut oil, waxy wax, rosin, And vegetable oil softeners such as pine oil. It is preferable to use one or more of these softeners. It is preferable to use paraffin wax as the softening agent. The content of the softening agent is, for example, 5 to 15 parts by mass with respect to 100 parts by mass of the rubber component.

  Examples of the antioxidant include amines such as aromatic secondary amines, quinoline, hydroquinone, phenols, and phosphite esters. It is preferable that an anti-aging agent contains 1 type, or 2 or more types of these. It is preferable to use an aromatic secondary amine-based antioxidant. The content of the antiaging agent is, for example, 0.1 to 1.5 parts by mass with respect to 100 parts by mass of the rubber component.

  Examples of the processing aid include stearic acid, polyethylene wax, and metal salts of fatty acids. It is preferable to use one or more of these processing aids. As the processing aid, stearic acid is preferably used. The content of the processing aid is, for example, 0.1 to 3 parts by mass with respect to 100 parts by mass of the rubber component.

  Examples of the vulcanization acceleration aid include metal oxides such as zinc oxide (zinc white) and magnesium oxide. It is preferable to use one or more of these vulcanization aids. Zinc oxide is preferably used as the vulcanization aid. The content of the vulcanization aid is, for example, 3 to 15 parts by mass with respect to 100 parts by mass of the rubber component.

  Examples of the crosslinking agent include organic peroxides. The rubber composition forming the back rubber layer 11 is preferably crosslinked with an organic oxide. As the cross-linking agent, an organic peroxide may be used alone, or an organic peroxide and sulfur may be used in combination. The compounding amount of the organic peroxide is, for example, 0.5 to 8 parts by mass with respect to 100 parts by mass of the rubber component. When the organic peroxide and sulfur are used in combination, the compounding amount of sulfur is the rubber component. For example, 0.5 to 4 parts by mass with respect to 100 parts by mass.

  Examples of the co-crosslinking agent include triallyl isocyanurate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, liquid polybutadiene, and N, N′-m-phenylenebismaleimide. It is preferable to use one or more of these co-crosslinking agents. As the co-crosslinking agent, triallyl isocyanurate is preferably used. The content of the co-crosslinking agent is preferably 1 to 5 parts by mass, more preferably 1 to 2 parts by mass with respect to 100 parts by mass of the rubber component.

  Similar to the back rubber layer 11, the adhesive rubber layer 12 is formed in a band shape having a horizontally long cross section. The compression rubber layer 13 is provided such that a plurality of V ribs 15 hang down to the belt inner peripheral side. The plurality of V ribs 15 are each formed in a ridge having a substantially inverted triangular cross section extending in the belt length direction, and arranged in parallel in the belt width direction. The surfaces of the plurality of V ribs 15 in the compressed rubber layer 13 constitute a pulley contact surface as a power transmission surface. Each V rib 15 has, for example, a rib height of 2.0 to 3.0 mm and a width between base ends of 1.0 to 3.6 mm. The number of V ribs is, for example, 3 to 6 (6 in FIG. 1).

  Each of the adhesive rubber layer 12 and the compressed rubber layer 13 is formed of a rubber composition that is crosslinked by heating and pressurizing an uncrosslinked rubber composition in which various compounding agents are blended with a rubber component. Therefore, each of the compressed rubber layer 13 and the adhesive rubber layer 12 contains a crosslinked rubber component and various compounding agents.

  Examples of the rubber component of the rubber composition forming the compression rubber layer 13 and the adhesive rubber layer 12 include ethylene-α-olefin elastomer, chloroprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), hydrogenated acrylonitrile rubber ( H-NBR) and the like. These rubber components are preferably the same as the rubber components of the rubber composition forming the back rubber layer 11.

  When the rubber component of the rubber composition forming the compressed rubber layer 13 contains EPDM, the ethylene content (C) of the EPDM is preferably 45% by mass or more, more preferably 50% by mass or more. , Preferably 65% by mass or less, more preferably 60% by mass or less. The ethylene content (C) is preferably smaller than the ethylene content (A) of EPDM contained in the rubber component of the rubber composition forming the back rubber layer 11.

  Ratio of ethylene content (A) of EPDM contained in the rubber component of the rubber composition forming the back rubber layer 11 to ethylene content (C) of EPDM contained in the rubber component of the rubber composition forming the compressed rubber layer 13 ( A / C) is preferably 1.02 or more, more preferably 1.13 or more, and preferably 1.91 or less, more preferably 1.52 or less.

  The diene content (D) of EPDM is preferably 3.5% by mass or more, more preferably 4.0% by mass or more, and preferably 8.0% by mass or less, more preferably 6.0% by mass or less. It is. This diene content (D) is preferably larger than the diene content (B) of EPDM contained in the rubber component of the rubber composition forming the back rubber layer 11.

  Ratio of the diene content (B) of EPDM contained in the rubber component of the rubber composition forming the back rubber layer 11 to the diene content (D) of EPDM contained in the rubber component of the rubber composition forming the compressed rubber layer 13 ( B / D) is preferably 0.0125 or more, more preferably 0.10 or more, and is preferably less than 1, more preferably 0.50 or less, still more preferably 0.20 or less, and even more. Preferably it is 0.15 or less.

  Examples of the diene component include ethylidene nobornene (ENB), dicyclopentadiene, 1,4-hexadiene, and the like. Among these, the diene component is preferably ethylidene nobornene. This diene component is preferably the same as the diene component of EPDM contained in the rubber component of the rubber composition forming the back rubber layer 11.

The Mooney viscosity at 125 ° C. of EPDM is preferably ₁₀ ML _{1 + 4} (125 ° C.) or more, more preferably 15 ML _{1 + 4} (125 ° C.) or more, preferably 70 ML _{1 + 4} (125 ° C.) or less, more preferably 50 ML _{1 + 4} ( 125 ° C.) or less.

  The EPDM contained in the rubber component of the rubber composition forming the compressed rubber layer 13 may be crosslinked with an organic peroxide, crosslinked with sulfur, or further crosslinked with a combination thereof. Or any of them.

  The core wire 14 is composed of twisted yarns such as polyester fiber (PET), polyethylene naphthalate fiber (PEN), aramid fiber, and vinylon fiber. The diameter of the core wire 14 is, for example, 0.5 to 2.5 mm, and the dimension between the centers of the adjacent core wires 14 in the cross section is, for example, 0.05 to 0.20 mm. The core wire 14 is dried after being dipped in an adhesive treatment and / or rubber paste that is heated after being immersed in an RFL aqueous solution before molding to give adhesion to the adhesive rubber layer 12 of the V-ribbed belt body 10. Bonding treatment is applied.

  Next, a method for manufacturing the V-ribbed belt B according to the first embodiment will be described.

  In the manufacture of the V-ribbed belt B according to the first embodiment, as shown in FIGS. 3 and 4, a belt forming die 20 having a cylindrical inner die 21 and an outer die 22 provided concentrically is used.

  In this belt mold 20, the inner mold 21 is formed of a flexible material such as rubber. The outer mold 22 is made of a rigid material such as metal. The inner peripheral surface of the outer mold 22 is formed as a molding surface, and V rib forming grooves 23 are provided on the inner peripheral surface of the outer mold 22 at a constant pitch in the axial direction. Further, the outer mold 22 is provided with a temperature control mechanism that controls the temperature by circulating a heat medium such as water vapor or a coolant such as water. The belt mold 20 is provided with a pressurizing means for pressurizing and expanding the inner mold 21 from the inside.

  In the manufacture of the V-ribbed belt B according to the first embodiment, first, each compounding agent is blended with the rubber component and kneaded by a kneader such as a kneader or a Banbury mixer. To form an uncrosslinked rubber sheet 11 'for the back rubber layer.

  Similarly, uncrosslinked rubber sheets 12 'and 13' for the adhesive rubber layer and the compressed rubber layer are also produced. Moreover, after performing the adhesion process which immerses and heats the strand 14 'for core wires in RFL aqueous solution, the adhesion process which immerses in rubber paste and heat-drys is performed.

  Next, as shown in FIG. 5, a rubber sleeve 25 is placed on a cylindrical drum 24 having a smooth surface, and an uncrosslinked rubber sheet 11 ′ for the back rubber layer and an uncrosslinked rubber sheet for the adhesive rubber layer are formed thereon. 12 ′ are wound in order and laminated, and then a strand 14 ′ for a core wire is spirally wound around the cylindrical inner mold 21, and further, an uncrosslinked rubber sheet 12 ′ for an adhesive rubber layer is further formed thereon. And uncrosslinked rubber sheet 13 'for compression rubber layers is wound in order, and uncrosslinked slab S' is formed. At this time, it is preferable to wind the uncrosslinked rubber sheets 11 ′, 12 ′, and 13 ′ so that the direction of alignment is the belt length direction (circumferential direction).

  Next, the rubber sleeve 25 provided with the uncrosslinked slab S ′ is removed from the cylindrical drum 24, and as shown in FIG. 6, it is set in an internally fitted state on the inner peripheral surface side of the outer mold 22.

  Next, as shown in FIG. 7, the inner mold 21 is positioned and sealed in the rubber sleeve 25 set in the outer mold 22.

  Subsequently, the outer mold 22 is heated, and high-pressure air or the like is injected into the sealed interior of the inner mold 21 to pressurize it. At this time, as shown in FIG. 8, the inner mold 21 expands, and the uncrosslinked rubber sheets 11 ′, 12 ′, and 13 ′ for forming the belt of the uncrosslinked slab S ′ are compressed on the molding surface of the outer mold 22. Further, the cross-linking of these rubber components proceeds to be integrated and combined with the twisted yarn 14 ′, and finally, a cylindrical belt slab S is formed. The molding temperature of the belt slab S is, for example, 100 to 180 ° C., the molding pressure is, for example, 0.5 to 2.0 MPa, and the molding time is, for example, 10 to 60 minutes.

  Then, the inside of the inner mold 21 is decompressed to release the seal, the belt slab S molded between the inner mold 21 and the outer mold 22 is taken out via the rubber sleeve 25, and the belt slab S is cut into a predetermined width. The V-ribbed belt B is obtained by turning the front and back. If necessary, the outer peripheral side of the belt slab S, that is, the surface on the V rib 15 side may be polished.

  FIG. 9 shows a pulley layout of an auxiliary drive belt transmission device 30 for an automobile using the V-ribbed belt B according to the first embodiment. This accessory drive belt transmission device 30 is of a serpentine drive type in which a V-ribbed belt B is wound around six pulleys, four rib pulleys and two flat pulleys, to transmit power.

  The auxiliary drive belt transmission device 30 includes a rib pulley power steering pulley 31 at the uppermost position, and a rib pulley AC generator pulley 32 below the power steering pulley 31. A flat pulley tensioner pulley 33 is provided at the lower left of the power steering pulley 31, and a flat pulley water pump pulley 34 is provided below the tensioner pulley 33. Further, a ribshaft crankshaft pulley 35 is provided on the lower left side of the tensioner pulley 33, and a rib pulley air conditioner pulley 36 is provided on the lower right side of the crankshaft pulley 35. These pulleys are made of, for example, a metal press-worked product, a cast, a resin molded product such as a nylon resin, a phenol resin, and the diameter of the pulley is 50 to 150 mm.

  In this accessory drive belt transmission 30, the V-ribbed belt B is wound around the power steering pulley 31 so that the V-rib 15 side contacts, and then wound around the tensioner pulley 33 so that the back side of the belt contacts. Further, the crankshaft pulley 35 and the air conditioner pulley 36 are wound around in order so that the V rib 15 side comes into contact, and further, they are wound around the water pump pulley 34 so that the back side of the belt comes into contact, and the V rib 15 side comes into contact. Is wound around an AC generator pulley 32 and finally returned to the power steering pulley 31. The belt span length, which is the length of the V-ribbed belt B spanned between the pulleys, is, for example, 50 to 300 mm. Misalignment that can occur between pulleys is 0-2 °.

  In the accessory drive belt transmission device 30 configured as described above, the V-ribbed belt B according to the first embodiment is wound so that the back rubber layer 11 on the back surface of the belt is in contact with the tensioner pulley 33 and the water pump pulley 34. The back rubber layer 11 is formed of a rubber composition mainly composed of a rubber component of EPDM having an ethylene content of 60% by mass or more and a diene content of 1% by mass or less. Adhesive wear can be suppressed.

(Embodiment 2)
10 and 11 show a V-ribbed belt B according to the second embodiment. In addition, the part of the same name as Embodiment 1 is shown using the same code | symbol as Embodiment 1. FIG.

  In the V-ribbed belt B according to the second embodiment, the compression rubber layer 13 includes a surface rubber layer 13a and a core rubber layer 13b. The surface rubber layer 13a is made of porous rubber, and is provided in layers so as to extend along the entire surface of the V-rib 15, and constitutes a pulley contact surface on the belt inner peripheral side. The thickness of the surface rubber layer 13a is, for example, 50 to 500 μm. The core rubber layer 13b is made of solid rubber, is provided inside the surface rubber layer 13a, and constitutes a portion of the compressed rubber layer 13 other than the surface rubber layer 13a.

  Here, the “porous rubber” in the present application means a crosslinked rubber composition having a number of hollow portions inside and a number of recessed holes 16 on the surface, and the hollow portions and the recessed holes 16 are dispersed. And a structure in which the hollow portion and the recessed hole 16 communicate with each other are included. In addition, the “solid rubber” in the present application means a crosslinked rubber composition that does not include a hollow portion other than the “porous rubber” and the concave hole 16.

  The surface rubber layer 13a and the core rubber layer 13b are formed of a rubber composition that is cross-linked by heating and pressurizing an uncrosslinked rubber composition in which various compounding agents are blended with a rubber component. Therefore, the surface rubber layer 13a and the core rubber layer 13b contain a crosslinked rubber component and various compounding agents. Since the surface rubber layer 13a is additionally a porous rubber, unexpanded hollow particles and / or a foaming agent for constituting the porous rubber are blended in the uncrosslinked rubber composition before the formation.

  Examples of the unexpanded hollow particles include particles in which a solvent is enclosed in a shell formed of a thermoplastic polymer (for example, acrylonitrile polymer). The hollow particles may be used alone or in combination of two or more. The compounding amount of the hollow particles is preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the rubber component. As the foaming agent, for example, an ADCA foaming agent containing azodicarbonamide as a main component, a DPT foaming agent containing dinitrosopentamethylenetetramine as a main component, and p, p′-oxybisbenzenesulfonylhydrazide as a main component. Examples thereof include organic foaming agents such as OBSH foaming agents and HDCA foaming agents mainly composed of hydrazodicarbonamide. It is preferable to use 1 type, or 2 or more types of these as a foaming agent. The blending amount of the foaming agent is preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the rubber component.

  The core rubber layer 13b is formed of a rubber composition containing a crosslinked rubber component and various compounding agents. The rubber composition for forming the core rubber layer 13b may be the same as the rubber composition for forming the surface rubber layer 13a excluding the hollow portion and the concave hole 16.

  Other configurations of the rubber composition forming the surface rubber layer 13a and the core rubber layer 13b are the same as the rubber composition forming the compression rubber layer 13 of the V-ribbed belt B according to the first embodiment.

  Since the surface rubber layer 13a is porous rubber, a large number of concave holes 16 are formed on the surface thereof. The average hole diameter of the concave holes 16 is preferably 10 to 150 μm. The average hole diameter of the concave holes 16 is determined by the number average of 50 to 100 measured by the surface image.

  To manufacture the V-ribbed belt B according to the second embodiment, uncrosslinked rubber sheets 13a 'and 13b' for the surface rubber layer and the core rubber layer of the compressed rubber layer 13 are produced. The uncrosslinked rubber sheet 13a 'for the surface rubber layer is blended with unexpanded hollow particles and / or a foaming agent. Next, as shown in FIG. 12, the uncrosslinked rubber sheet 11 ′ for the back rubber layer and the adhesive rubber are formed on the rubber sleeve 25 covered on the cylindrical drum 24 having a smooth surface as shown in FIG. The uncrosslinked rubber sheet 12 ′ for the layers is wound in order and laminated, and the twisted wire 14 ′ for the core wire is spirally wound around the cylindrical inner mold 21 from above, and the adhesive rubber layer is further wound thereon. The uncrosslinked rubber sheet 12 ′, the uncrosslinked rubber sheet 13b ′ for the core rubber layer in the compressed rubber layer 13, and the uncrosslinked rubber sheet 13a ′ for the surface rubber layer are wound in order to form an uncrosslinked slab S ′. Then, a cylindrical belt slab S as shown in FIG. 13 is formed by the uncrosslinked slab S ′.

  Other configurations and operational effects are the same as those of the first embodiment.

(Other embodiments)
In the first and second embodiments, the V-ribbed belt B is shown, but is not particularly limited thereto, and is not particularly limited as long as it is a transmission belt having a back rubber layer on the belt outer peripheral side. For example, a low-edge type V-belt B as shown in FIG. 14A or a toothed belt as shown in FIG. 14B may be used.

(V-ribbed belt)
V-ribbed belts of Examples 1 to 5 and Comparative Examples 1 to 5 below were produced. Each configuration is also shown in Table 1.

<Example 1>
EPDM (1) as a rubber component in a chamber of a closed Banbury mixer (trade name: Nordel 3745P, manufactured by Dow, ethylene content (A): 70% by mass, diene content (B) (ethylidene norbornene content (ENB content)): 0.5 mass%, Mooney viscosity: 45 ML _{1 + 4} (125 ° C.) was added and masticated, and then carbon black ISAF (manufactured by Tokai Carbon Co., Ltd.) as a reinforcing material for 100 parts by mass of this rubber component Name: Seast 6) 50 parts by mass, softener paraffin wax (trade name: Sunflex 2280, manufactured by Nippon San Oil Co., Ltd.), aromatic secondary amine type anti-aging agent (produced by Ouchi Shinsei Chemical Co., Ltd.) Name: Nocrack CD) 0.5 part by mass, processing aid stearic acid (manufactured by NOF Corporation, trade name: bead stearic acid 酸) 0.5 mass , Zinc oxide (trade name: Zinc Oxide 3 types, manufactured by Sakai Chemical Co., Ltd.) 8 parts by mass, crosslinking agent organic peroxide (product name: Peroximon F40 (purity 40% by mass), 8 parts by mass (3.2 parts by mass) of α, α'-di (tri-t-butylperoxy) diisopropylbenzene) were added and kneaded, and a back rubber layer was formed using the obtained uncrosslinked rubber composition. A V-ribbed belt having the same configuration as that of the second embodiment was produced. This was designated Example 1.

The surface rubber layer of the compression rubber layer was formed of porous rubber of another rubber composition containing EPDM as a rubber component. The rubber component of the rubber composition forming the surface rubber layer is mainly composed of ethylene content (C): 67 mass%, diene content (D): 4.5 mass%, Mooney viscosity: 27 ML _{1 + 4} (125 ° C.). EPDM was used. The core rubber layer and the adhesive rubber layer of the compression rubber layer were formed of another rubber composition containing EPDM as a rubber component. The core wire was composed of a twisted yarn made of polyethylene terephthalate fiber. Further, the compressed rubber layer was subjected to surface polishing. The belt length was 1100 mm, the belt width was 21.36 mm, the belt thickness was 4.3 mm, and the number of ribs was six.

<Example 2>
In place of ISAF of carbon black, FEF (trade name: Seast SO manufactured by Tokai Carbon Co., Ltd.) is used, and triallyl isocyanurate (trade name: Nippon Chemical Co., Ltd. manufactured by Nippon Kasei Co., Ltd.) is used for 100 parts by mass of the rubber component. A V-ribbed belt having the same configuration as in Example 1 was produced except that 2 parts by mass was used. This was designated Example 2.

<Example 3>
A V-ribbed belt having the same configuration as in Example 1 was produced except that 10 parts by mass of magnesium carbonate (trade name: Venus, manufactured by Kamishima Chemical Industry Co., Ltd.) as a filler was used with respect to 100 parts by mass of the rubber component. This was designated Example 3.

<Example 4>
FEF is used in place of the ISAF of carbon black, the filler magnesium carbonate is used in an amount of 10 parts by mass with respect to 100 parts by mass of the rubber component, and the co-crosslinking agent triallyl isocyanurate is 2 parts by mass with respect to 100 parts by mass of the rubber component. A V-ribbed belt having the same configuration as that of Example 1 except that the mass part was used was produced. This was designated Example 4.

<Example 5>
EPDM (2) (trade name: Nordel 3720P, manufactured by Dow, ethylene content (A): 69 mass%, diene content (B): 0.5 mass%, Mooney viscosity: 20 ML _{1 + 4} (125 ° C.)) is used as a rubber component. In addition, a V-ribbed belt having the same configuration as that of Example 1 was prepared except that 10 parts by mass of magnesium carbonate as a filler was used with respect to 100 parts by mass of the rubber component. This was designated Example 5.

<Comparative Example 1>
EPDM (3) (trade name: EP22, manufactured by JSR, ethylene content (A): 54 mass%, diene content (B): 4.5 mass%, Mooney viscosity: 27 ML _{1 + 4} (125 ° C.)) is used as a rubber component. In addition, 1.7 parts by mass of insoluble sulfur (trade name: Seimi OT, manufactured by Nippon Kiboshi Kogyo Co., Ltd.) is used in place of 100 parts by mass of the rubber component instead of the organic peroxide of the crosslinking agent, and sulfenamide-based vulcanization is accelerated. Agent (trade name: Noxeller MSA-G manufactured by Ouchi Shinsei Chemical Co., Ltd.) with respect to 100 parts by mass of the rubber component, and mixed vulcanization accelerators of thiuram, dithiocarbamate, and thiazole ( A V-ribbed belt having the same configuration as in Example 1 was produced except that 2.8 parts by mass of Sanshin Chemical Co., Ltd. trade name: Sunceller EM2) was used with respect to 100 parts by mass of the rubber component. This was designated as Comparative Example 1.

<Comparative example 2>
A V-ribbed belt having the same configuration as that of Comparative Example 1 was produced except that 10 parts by mass of magnesium carbonate as a filler was used with respect to 100 parts by mass of the rubber component. This was designated as Comparative Example 2.

<Comparative Example 3>
EPDM (4) (trade name: Nordel 3640, manufactured by Dow, ethylene content (A): 55 mass%, diene content (B): 1.8 mass%, Mooney viscosity: 40 ML _{1 + 4} (125 ° C.)) is used as a rubber component. A V-ribbed belt having the same configuration as that of Example 4 was prepared except that the above-described cases were observed. This was designated as Comparative Example 3.

<Comparative Example 4>
EPDM (5) (trade name: EP43, manufactured by JSR, ethylene content (A): 54 mass%, diene content (B): 4.5 mass%, Mooney viscosity: 27 ML _{1 + 4} (125 ° C.)) is used as a rubber component. In addition, a V-ribbed belt having the same configuration as that of Example 1 was prepared except that FEF was used instead of carbon black ISAF. This was designated as Comparative Example 4.

<Comparative Example 5>
A V-ribbed belt having the same configuration as that of Comparative Example 4 was produced except that 2 parts by mass of triallyl isocyanurate as a co-crosslinking agent was used based on 100 parts by mass of the rubber component. This was designated as Comparative Example 5.

(Test evaluation method)
FIG. 15 shows a pulley layout of the belt running test machine 40.

  In the belt running test machine 40, a driving pulley 41 and a driven pulley 42, which are flat pulleys each having a pulley diameter of 70 mm and a surface roughness of 12.5Z (according to TSZ2301G), are provided on the left and right sides with an interval therebetween.

  For each of Examples 1 to 5 and Comparative Examples 1 to 5, the drive pulley 41 and the driven pulley 42 of the belt running test machine 40 are wound around the V-ribbed belt B so that the back rubber layer on the outer peripheral side is in contact with each other. A torque of 22.5 N · m is applied to the driven pulley 42, and a load of 1177 N is applied to the side (in the direction opposite to the drive pulley 41) so that the belt tension is applied, and the ambient temperature is 25 ± 7 ° C. The drive pulley 41 was rotated at a rotational speed of 3500 rpm to run the belt. The belt run was performed up to 60 minutes, and the adhesive wear situation at the time of 30 minutes and the adhesive wear situation of the surface of the back rubber layer at the time of 60 minutes were visually confirmed and evaluated. Evaluation was carried out in five stages of adhesive wear: none, minute, small, medium and large.

(Test results)
The test results are shown in Table 1.

According to the test results, Examples 1 to 5 in which the back rubber layer was formed of an EPDM rubber composition having an ethylene content of 60% by mass or more and a diene content of 1% by mass or less were obtained after 30 minutes of running. In there is nothing to minute, and after 60 minutes it is minute to small,
Comparative Examples 1 to 5 having an ethylene content of less than 60% by mass or a diene content of 1% by mass or more are small to large after 30 minutes of running, and are medium to large after 60 minutes of running. In other words, it can be seen that Examples 1 to 5 are more excellent in adhesive wear resistance than Comparative Examples 1 to 5.

  The present invention is useful in the technical field of power transmission belts.

B V-ribbed belt, V-belt, toothed belt (power transmission belt)
11 Back rubber layer 13 Compressed rubber layer (surface rubber layer)
13a Surface rubber layer

Claims (11)

A power transmission belt having a back rubber layer on the belt outer peripheral side and a surface rubber layer on the belt inner peripheral side,
The back rubber layer is formed of a rubber composition mainly composed of an ethylene-propylene-diene terpolymer having an ethylene content of 60% by mass or more and a diene content of 1% by mass or less. The rubber layer is formed of a rubber composition mainly composed of an ethylene-propylene-diene terpolymer,
The ethylene content of the ethylene-propylene-diene terpolymer contained in the rubber composition forming the surface rubber layer is more than the ethylene content of the ethylene-propylene-diene terpolymer contained in the rubber composition forming the back rubber layer. Small transmission belt. The power transmission belt according to claim 1 ,
The ethylene-propylene-diene terpolymer contained in the rubber component of the rubber composition forming the back rubber layer with respect to the ethylene content of the ethylene-propylene-diene terpolymer contained in the rubber component of the rubber composition forming the surface rubber layer A transmission belt having an ethylene content ratio of 1.02 or more. A power transmission belt having a back rubber layer on the belt outer peripheral side and a surface rubber layer on the belt inner peripheral side,
The back rubber layer is formed of a rubber composition mainly composed of an ethylene-propylene-diene terpolymer having an ethylene content of 60% by mass or more and a diene content of 1% by mass or less. The rubber layer is formed of a rubber composition mainly composed of an ethylene-propylene-diene terpolymer,
The diene content of the ethylene-propylene-diene terpolymer contained in the rubber composition forming the surface rubber layer is more than the diene content of the ethylene-propylene-diene terpolymer contained in the rubber composition forming the back rubber layer. Big transmission belt. In the transmission belt according to claim 3 ,
The ethylene-propylene-diene terpolymer contained in the rubber component of the rubber composition forming the back rubber layer with respect to the diene content of the ethylene-propylene-diene terpolymer contained in the rubber component of the rubber composition forming the surface rubber layer A transmission belt having a diene content ratio of 0.50 or less. The transmission belt according to any one of claims 1 to 4 ,
A power transmission belt in which the rubber composition forming the back rubber layer contains a co-crosslinking agent. The transmission belt according to claim 5 ,
A power transmission belt in which the rubber composition forming the back rubber layer contains triallyl isocyanurate as the co-crosslinking agent. In the transmission belt according to claim 5 or 6 ,
The power transmission belt whose content of the said co-crosslinking agent in the rubber composition which forms the said back rubber layer is 1-5 mass parts with respect to 100 mass parts of said rubber components. The transmission belt according to any one of claims 1 to 7,
A power transmission belt in which the rubber composition forming the back rubber layer contains a filler. The transmission belt according to claim 8, wherein
A power transmission belt in which the rubber composition forming the back rubber layer contains magnesium carbonate as the filler. In the transmission belt according to claim 8 or 9 ,
The power transmission belt whose content of the said filler in the rubber composition which forms the said back rubber layer is 5-20 mass parts with respect to 100 mass parts of said rubber components. The power transmission belt according to any one of claims 1 to 10 ,
A power transmission belt in which a rubber composition forming the back rubber layer is crosslinked with an organic oxide.

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