JPWO2016021096A1 - Friction transmission belt, method for manufacturing the same, and belt transmission device - Google Patents

Abstract

The friction transmission belt (B) has a rubber layer (11) that constitutes a pulley contact portion on the inner peripheral side of the belt. The rubber layer (11) is formed of a rubber composition in which a rubber component mainly composed of an ethylene-α-olefin elastomer is blended with a vulcanization accelerator having a thiocarbonyl group and is crosslinked with an organic peroxide. Yes.

Description

  The present invention relates to a friction transmission belt, a manufacturing method thereof, and a belt transmission device.

  It is known to form a compressed rubber layer on the inner circumference side of a friction transmission belt with a rubber composition in which EPDM is blended with sulfur as a crosslinking agent and a vulcanization accelerator. For example, Patent Document 1 discloses that a compression rubber layer of a friction transmission belt is made of EPDM, 100 parts by mass of sulfur, 1 part by mass of sulfur as a crosslinking agent, 1 part by mass of a thiuram vulcanization accelerator, and a thiazole series. It is disclosed that a rubber composition containing 1 part by mass of a vulcanization accelerator is formed.

JP 2006-138355 A

  The present invention is a friction transmission belt having a rubber layer constituting a pulley contact portion on the inner circumference side of the belt, and the rubber layer has a thiocarbonyl group in a rubber component mainly composed of an ethylene-α-olefin elastomer. It is formed of a rubber composition blended with a vulcanization accelerator and crosslinked with an organic peroxide.

It is a perspective view of the V-ribbed belt which concerns on embodiment. It is a figure which shows the pulley layout of the auxiliary drive belt transmission apparatus of the motor vehicle using the V-ribbed belt which concerns on embodiment. It is the 1st explanatory view showing the manufacturing method of the V ribbed belt concerning an embodiment. It is the 2nd explanatory view showing the manufacturing method of the V ribbed belt concerning an embodiment. It is the 3rd explanatory view showing the manufacturing method of the V ribbed belt concerning an embodiment. It is a 4th explanatory view showing the manufacturing method of the V ribbed belt concerning an embodiment. It is a 5th explanatory view showing the manufacturing method of the V ribbed belt concerning an embodiment. It is a perspective view of the modification of the V-ribbed belt which concerns on embodiment. It is a perspective view of the low edge type V belt concerning other embodiments. It is a perspective view of the flat belt which concerns on other embodiment. It is a figure which shows the pulley layout of the belt running test machine for heat resistance and bending resistance evaluation. It is a figure which shows the pulley layout of the belt running test machine for abrasion resistance evaluation.

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

(V-ribbed belt)
FIG. 1 shows a V-ribbed belt B (friction transmission belt) according to the embodiment. The V-ribbed belt B according to the 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 the embodiment 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 embodiment includes a rubber V-ribbed belt main body 10 configured as a double layer of a compression rubber layer 11 constituting a pulley contact portion on the belt inner peripheral side and an adhesive rubber layer 12 on the belt outer peripheral side. ing. A back reinforcing cloth 13 is attached to the belt outer peripheral side of the adhesive rubber layer 12 in the V-ribbed belt main body 10. A core wire 14 is embedded in an intermediate portion in the thickness direction of the adhesive rubber layer 12 so as to form a spiral having a pitch in the belt width direction. Note that a configuration in which a back rubber layer is provided instead of the back reinforcing cloth 13 may be employed.

  The compressed rubber layer 11 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. 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).

  The compressed rubber layer 11 is formed of a rubber composition obtained by crosslinking an uncrosslinked rubber composition obtained by mixing and kneading various rubber compounding ingredients with a rubber component by heating and pressurizing.

  The rubber component of the rubber composition forming the compressed rubber layer 11 is mainly composed of an ethylene-α-olefin elastomer. The content of the ethylene-α-olefin elastomer 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. The rubber component may contain, for example, chloroprene rubber or hydrogenated nitrile rubber in addition to the ethylene-α-olefin elastomer.

  Examples of the ethylene-α-olefin elastomer include ethylene-propylene-diene terpolymer (hereinafter referred to as “EPDM”), ethylene-propylene copolymer (EPM), ethylene-butene copolymer (EDM), and ethylene-octene copolymer (EOM). Etc. Of these, EPDM is preferred. The rubber component may contain only one ethylene-α-olefin elastomer among the above or may contain two or more ethylene-α-olefin elastomers.

  The ethylene content of the ethylene-α-olefin elastomer is preferably 48% by mass or more, more preferably 50% by mass or more, still more preferably 52% by mass or more, and preferably 70% by mass or less, more preferably 65% by mass. % Or less, more preferably 62% by mass or less.

  In the case of EPDM, examples of the diene component include ethylidene nobornene, dicyclopentadiene, 1,4-hexadiene, and the like. Of these, ethylidene nobornene is preferred. The diene component content is preferably 1.5% by mass or more, more preferably 2.5% by mass or more, still more preferably 3.0% by mass or more, and preferably 10.0% by mass or less, more preferably It is 9.0 mass% or less, More preferably, it is 8.0 mass% or less.

The Mooney viscosity of the ethylene-α-olefin elastomer is preferably ₁₀ ML _{1 + 4} (125 ° C.) or higher, more preferably 15 ML _{1 + 4} (125 ° C.) or higher, and preferably 100 ML _{1 + 4} (125 ° C.) or lower, more preferably 80 ML. _{1 + 4} (125 ° C.) or less. Mooney viscosity is measured based on JISK6300.

  The rubber composition forming the compressed rubber layer 11 is crosslinked with an organic peroxide. That is, an organic peroxide is blended in the uncrosslinked rubber composition before the formation of the compressed rubber layer 11 as a crosslinking agent.

  Examples of the organic peroxide include dicumyl peroxide, 1,3-bis (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, and the like. . As for the organic peroxide, either one of the above may be blended or two or more may be blended. The content of the organic peroxide in the uncrosslinked rubber composition before the formation of the compressed rubber layer 11 is preferably 0.2% by mass or more, more preferably 0.5% by mass or more, and further preferably 0.7% by mass. Further, it is preferably 6.5% by mass or less, more preferably 5.5% by mass or less, and further preferably 5.0% by mass or less.

  The rubber composition forming the compressed rubber layer 11 may be crosslinked with sulfur. That is, in addition to the organic peroxide, sulfur may be blended in the uncrosslinked rubber composition before the formation of the compressed rubber layer 11 as a crosslinking agent.

  The sulfur content in the uncrosslinked rubber composition before the formation of the compressed rubber layer 11 is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and further preferably 0.4% by mass or more. Moreover, it is preferably 1.7% by mass or less, more preferably 1.5% by mass or less, and still more preferably 1.2% by mass or less. The ratio of sulfur content to organic peroxide content in the uncrosslinked rubber composition before formation of the compressed rubber layer 11 (sulfur content / organic peroxide content) is preferably 0.1 or more. More preferably, it is 0.2 or more, More preferably, it is 0.25 or more, Preferably it is 2.0 or less, More preferably, it is 1.5 or less, More preferably, it is 1.3 or less. The content of sulfur in the uncrosslinked rubber composition before the formation of the compressed rubber layer 11 is preferably larger than the content of organic peroxide.

  The rubber composition forming the compressed rubber layer 11 is blended with a vulcanization accelerator having a thiocarbonyl group.

  Examples of the vulcanization accelerator having a thiocarbonyl group include thiourea vulcanization accelerators such as N, N′-diphenylthiourea, trimethylthiourea (TMU), and N, N′-diethylthiourea (DEU); Thiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), tetrabutylthiuram disulfide (TBTD), tetrakis (2-ethylhexyl) thiuram disulfide, tetramethylthiuram monosulfide (TMTM), dipentamethylenethiuram tetrasulfide (DPTT), etc. Thiuram vulcanization accelerator: piperidinium pentamethylene dithiocarbamate (PPDC), zinc dimethyldithiocarbamate (ZnMDC), zinc diethyldithiocarbamate (ZnEDC), dibutyldithiocarbamine Zinc (ZnBDC), zinc ethylphenyldithiocarbamate (ZnEPDC), zinc N-pentamethylenedithiocarbamate (ZnPDC), zinc dibenzyldithiocarbamate, sodium dibutyldithiocarbamate (NaBDC), copper dimethyldithiocarbamate (CuMDC), dimethyldithiocarbamic acid Examples include dithiocarbamate vulcanization accelerators such as ferric iron (FeMDC) and tellurium diethyldithiocarbamate (TeEDC); xanthate vulcanization accelerators such as zinc isopropylxanthate and the like. Of these, thiuram vulcanization accelerators and dithiocarbamate vulcanization accelerators are preferred, and thiuram vulcanization accelerators are more preferred. One of the vulcanization accelerators having a thiocarbonyl group may be blended, or two or more may be blended.

  The blending amount of the vulcanization accelerator having a thiocarbonyl group with respect to 100 parts by mass of the rubber component is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and further preferably 0.8 parts by mass or more. Moreover, it is preferably 3.0 parts by mass or less, more preferably 2.5 parts by mass or less, and still more preferably 2.0 parts by mass or less. The content of the vulcanization accelerator having a thiocarbonyl group in the uncrosslinked rubber composition before the formation of the compressed rubber layer 11 is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and still more preferably. It is 0.3 mass% or more, preferably 2.2 mass% or less, more preferably 1.9 mass% or less, and still more preferably 1.7 mass% or less. Ratio of content of vulcanization accelerator having thiocarbonyl group to content of organic peroxide in uncrosslinked rubber composition before formation of compressed rubber layer 11 (content of vulcanization accelerator having thiocarbonyl group / The content of the organic peroxide) is preferably 0.1 or more, more preferably 0.3 or more, still more preferably 0.5 or more, and preferably 1.0 or less, more preferably 0.8. Hereinafter, more preferably 0.7 or less. The content of the vulcanization accelerator having a thiocarbonyl group in the uncrosslinked rubber composition before the formation of the compressed rubber layer 11 is preferably smaller than the content of the organic peroxide. When sulfur is blended as a crosslinking agent, the ratio of the content of the vulcanization accelerator having a thiocarbonyl group to the content of sulfur in the uncrosslinked rubber composition before the formation of the compressed rubber layer 11 (addition of a thiocarbonyl group) Sulfur accelerator content / sulfur content) is preferably 0.1 or more, more preferably 0.3 or more, still more preferably 0.5 or more, and preferably 6.0 or less, more preferably Is 3.0 or less, more preferably 2.0 or less. The content of the vulcanization accelerator having a thiocarbonyl group in the uncrosslinked rubber composition before the formation of the compressed rubber layer 11 is preferably the same as the sulfur content or less than the sulfur content.

  The rubber composition forming the compressed rubber layer 11 may contain only a vulcanization accelerator having a thiocarbonyl group, and a vulcanization accelerator other than the vulcanization accelerator having a thiocarbonyl group is used in combination. And may be blended. Examples of vulcanization accelerators other than those having a thiocarbonyl group include aldehyde-ammonia vulcanization accelerators, aldehyde-amine vulcanization accelerators, thiourea vulcanization accelerators, and guanidine vulcanization accelerators. Agents, thiazole vulcanization accelerators, sulfenamide vulcanization accelerators, and the like.

  Short fibers 16 may be blended in the rubber composition forming the compressed rubber layer 11. In that case, the short fibers 16 are preferably included in the compressed rubber layer 11 so as to be oriented in the belt width direction, and the short fibers 16 exposed on the surface of the V ribs 15 of the compressed rubber layer 11 are partially Preferably protrudes from the surface. In addition, the structure by which the short fiber 16 was planted on the V-rib 15 surface of the compression rubber layer 11 instead of the structure in which the short fiber 16 was mix | blended with the rubber composition may be sufficient.

  Examples of the short fibers 16 include nylon short fibers, vinylon short fibers, aramid short fibers, polyester short fibers, and cotton short fibers. The short fiber 16 is manufactured by, for example, cutting a long fiber that has been subjected to an adhesion treatment to be heated after being immersed in an RFL aqueous solution or the like into a predetermined length. For example, the short fibers 16 have a length of 0.2 to 5.0 mm and a fiber diameter of 10 to 50 μm. The compounding quantity with respect to 100 mass parts of rubber components of the short fiber 16 is 3-50 mass parts, for example.

  Examples of other rubber compounding agents blended in the rubber composition forming the compressed rubber layer 11 include, for example, reinforcing materials such as carbon black, softening agents, vulcanization accelerating aids, processing aids, anti-aging agents, and co-crosslinking. Agents and the like.

  The adhesive rubber layer 12 is configured in a band shape having a horizontally long cross section, and has a thickness of, for example, 1.0 to 2.5 mm. The adhesive rubber layer 12 is formed of a rubber composition in which an uncrosslinked rubber composition obtained by blending various rubber compounding ingredients with a rubber component and kneaded is heated and pressurized to be crosslinked with a crosslinking agent.

  The rubber composition for forming the adhesive rubber layer 12 may be one obtained by crosslinking an organic peroxide as a crosslinking agent, or one obtained by crosslinking sulfur as a crosslinking agent. Either a sulfur crosslinking agent may be used as a crosslinking agent and the crosslinking may be used.

  Examples of the rubber component of the rubber composition forming the adhesive rubber layer 12 include ethylene-α-olefin elastomer (EPDM, EPR, etc.), chloroprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), hydrogenated acrylonitrile rubber. (H-NBR) and the like. The rubber component of the rubber composition forming the adhesive rubber layer 12 is preferably the same as the rubber component of the rubber composition forming the compressed rubber layer 11.

  When the rubber component of the rubber composition forming the adhesive rubber layer 12 is an ethylene-α-olefin elastomer, the ethylene content is preferably 48% by mass or more, more preferably 50% by mass or more, and further preferably 52% by mass or more. Moreover, it is preferably 70% by mass or less, more preferably 65% by mass or less, and still more preferably 62% by mass or less. The ethylene content is preferably higher than the ethylene content when the rubber component of the rubber composition forming the compressed rubber layer 11 is an ethylene-α-olefin elastomer.

  When the rubber component of the rubber composition forming the adhesive rubber layer 12 is EPDM, examples of the diene component include ethylidene nobornene, dicyclopentadiene, 1,4-hexadiene, and the like. Of these, ethylidene nobornene is preferred. The diene component content is preferably 1.5% by mass or more, more preferably 2.5% by mass or more, still more preferably 3.0% by mass or more, and preferably 10.0% by mass or less, more preferably It is 9.0 mass% or less, More preferably, it is 8.0 mass% or less. This diene content is preferably higher than the diene content when the rubber component of the rubber composition forming the compressed rubber layer 11 is EPDM.

When the rubber component of the rubber composition forming the adhesive rubber layer 12 is an ethylene-α-olefin elastomer, its Mooney viscosity is preferably ₁₀ ML _{1 + 4} (125 ° C.) or more, more preferably 15 ML _{1 + 4} (125 ° C.) or more. Moreover, Preferably it is 100ML1 _{+ 4} (125 degreeC) or less, More preferably, it is 80ML1 _{+ 4} (125 degreeC) or less. This Mooney viscosity is preferably higher than the Mooney viscosity when the rubber component of the rubber composition forming the compressed rubber layer 11 is an ethylene-α-olefin elastomer.

  Examples of the rubber compounding agent blended in the rubber composition forming the adhesive rubber layer 12 include a reinforcing material such as carbon black, a softening agent, a vulcanization accelerating aid, a processing aid, an anti-aging agent, a co-crosslinking agent, Examples thereof include a crosslinking agent and a vulcanization accelerator.

  The back reinforcing cloth 13 is made of, for example, a cloth material such as a woven fabric, a knitted fabric, or a non-woven fabric formed of yarns such as cotton, polyamide fiber, polyester fiber, and aramid fiber. The thickness of the back reinforcing cloth 13 is, for example, 0.4 to 1.5 mm. The back reinforcing cloth 13 is subjected to a bonding process for bonding to the V-ribbed belt main body 10.

  The core wire 14 is composed of a twisted yarn formed of polyamide fiber, polyester fiber, aramid fiber, polyamide fiber or the like. The diameter of the core wire is, for example, 0.5 to 2.5 mm, and the dimension between the centers of adjacent core wires 14 in the cross section is, for example, 0.05 to 0.20 mm. The core wire 14 is also subjected to a bonding process for bonding to the V-ribbed belt body 10.

  According to the V-ribbed belt B according to the embodiment having the above-described configuration, the rubber composition that forms the compressed rubber layer 11 constituting the pulley contact portion on the inner peripheral side of the belt is a rubber component mainly composed of an ethylene-α-olefin elastomer. In addition, a high durability of the V-ribbed belt B can be obtained by forming a rubber composition blended with a vulcanization accelerator having a thiocarbonyl group and crosslinked with an organic peroxide.

(Automotive accessory drive belt drive)
FIG. 2 shows a pulley layout of an auxiliary drive belt transmission device 20 for an automobile using the V-ribbed belt B according to the embodiment. The accessory drive belt transmission device 20 is of a serpentine drive type in which a V-ribbed belt B is wound around six pulleys of four rib pulleys and two flat pulleys to transmit power.

  In this accessory drive belt transmission device 20, a power steering pulley 21 of a rib pulley is provided at the uppermost position, and an AC generator pulley 22 of a rib pulley is provided diagonally to the right of the power steering pulley 21. Further, a flat pulley tensioner pulley 23 is provided diagonally to the left of the power steering pulley 21, and a flat pulley water pump pulley 24 is provided below the tensioner pulley 23. Further, a rib pulley crankshaft pulley 25 is provided obliquely to the left of the tensioner pulley 23 and the water pump pulley 24, and a rib pulley air conditioner pulley 26 is provided obliquely to the right of the water pump pulley 24 and the crankshaft pulley 25. It has been. 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 device 20, the V-ribbed belt B is wound around the power steering pulley 21 so that the V-rib 15 side comes into contact, and then around the tensioner pulley 23 so that the back surface of the belt comes into contact. After that, it is wound around the crankshaft pulley 25 and the air conditioner pulley 26 in order so that the V-rib 15 side comes into contact, and is further wound around the water pump pulley 24 so that the back surface of the belt comes into contact. Thus, it is wound around the AC generator pulley 22 and finally returned to the power steering pulley 21. 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 °.

(Manufacturing method of V-ribbed belt B)
A method for manufacturing the V-ribbed belt B according to the embodiment will be described with reference to FIGS.

  The manufacturing method of the V-ribbed belt B according to the embodiment includes a preparation process, a molding process, a bridging process, a grinding process, and a width cutting process, and the V-rib 15 of the V-ribbed belt B is formed by grinding in the grinding process.

<Preparation process>
First, each rubber compounding agent is blended with a rubber component and kneaded with a kneader such as a kneader or a Banbury mixer, and the resulting uncrosslinked rubber composition is molded into a sheet shape by calendering or the like and used for the compressed rubber layer 11. An uncrosslinked rubber sheet 11 ′ is produced. At this time, a rubber component mainly composed of an ethylene-α-olefin elastomer is used, a vulcanization accelerator having a thiocarbonyl group is used, and an organic peroxide is used as a crosslinking agent. When the rubber composition forming the compressed rubber layer 11 is also crosslinked with sulfur, sulfur may be further added to the uncrosslinked rubber sheet 12 ′ as a crosslinking agent. When the short fiber 16 is included in the compressed rubber layer 11, the short fiber 16 may be blended with the uncrosslinked rubber sheet 12 ′. Similarly, an uncrosslinked rubber sheet 12 ′ for the adhesive rubber layer 12 is also produced.

  Further, an adhesive treatment is applied to the cloth material 13 ′ constituting the back reinforcing cloth 13. Specifically, for the cloth material 13 ′, an adhesive treatment in which it is immersed in a primer solution and heated, an adhesive treatment in which it is immersed in an RFL aqueous solution and heated, an adhesive treatment in which it is immersed in rubber glue and dried, and a V-ribbed belt body One or two or more types of adhesive treatments are applied among the adhesive treatments in which the surface on the 10 side is coated with rubber paste and dried.

  Further, an adhesive treatment is applied to the twisted yarn 14 ′ constituting the core wire 14. Specifically, the twisted yarn 14 ′ is subjected to an adhesive treatment in which it is immersed in a primer solution and heated, an adhesive treatment in which it is immersed in an RFL aqueous solution and heated, and an adhesive treatment in which it is immersed in rubber paste and dried.

<Molding process>
Next, as shown in FIG. 3, on the outer periphery of the cylindrical mold 31, the cloth material 13 ′ subjected to the bonding treatment constituting the back reinforcing cloth 13 and the uncrosslinked rubber sheet 12 ′ for the bonding rubber layer 12 are wound in order. The twisted yarn 14 ′ subjected to the bonding treatment constituting the core wire 14 is wound around the cylindrical mold 31 by applying a certain tension spirally to the cylindrical mold 31, and further, the twisted yarn 14 ′ for the adhesive rubber layer 12 is further wound thereon. An uncrosslinked rubber sheet 12 ′ and an uncrosslinked rubber sheet 11 ′ for the compressed rubber layer 11 are wound in order and laminated to form a belt forming molded body B ′. At this time, the uncrosslinked rubber sheet 12 ′ for the adhesive rubber layer 12 is wound so that the drawing direction which is the drawing direction corresponds to the belt length direction, and the uncrosslinked rubber sheet 11 ′ for the compressed rubber layer 11 is wound. Is wound so that the reverse direction perpendicular to the direction of the line corresponds to the belt length direction.

<Crosslinking process>
Next, as shown in FIG. 4, the rubber sleeve 32 is placed on the belt-forming molded body B ′, and the rubber sleeve 32 is placed and sealed in the vulcanizing can, and the vulcanizing can is filled with high-temperature and high-pressure steam. Hold for a predetermined time. At this time, the cross-linking of the uncrosslinked rubber sheets 11 ′ and 12 ′ proceeds and integrates, and is combined with the cloth material 13 ′ and the twisted yarn 14 ′. As shown in FIG. 5, finally, a cylindrical belt slab is obtained. S is molded.

<Grinding process>
Subsequently, the steam is discharged from the inside of the vulcanizing can to release the sealing, the belt slab S molded on the cylindrical mold 31 is removed, and the belt slab S is connected to a pair of slab spanning shafts as shown in FIG. 33, and a belt slab S is brought into contact with the outer peripheral surface of the belt slab S while rotating a grinding wheel 34 in which a circumferentially extending V-rib groove is continuously provided in the axial direction of the outer peripheral surface. By rotating S between the pair of slab spanning shafts 33, the outer peripheral surface thereof is ground over the entire circumference. At this time, as shown in FIG. 7, V-ribs 15 are formed on the outer peripheral surface of the belt slab S. The belt slab S may be divided by grinding in the length direction as necessary.

<Width cutting process>
Then, the belt slab S on which the V ribs 15 are formed by grinding is cut into a predetermined width and turned upside down to obtain the V ribbed belt B.

(Other embodiments)
In the above-described embodiment, the single-layered compression rubber layer 11 constituting the pulley contact portion on the inner peripheral side of the belt is provided. However, the present invention is not particularly limited to this, and as shown in FIG. The layer 11 may be configured to include a surface rubber layer 11a constituting a pulley contact portion on the belt inner peripheral side and an internal rubber layer 11b inside the surface rubber layer 11a.

  In the above embodiment, the V-ribbed belt B is used as an example. However, the transmission belt is not particularly limited as long as it is a transmission belt having the adhesive rubber layer 12 in which the core wire 14 is embedded. For example, as shown in FIG. A low edge type V-belt B or a flat belt B as shown in FIG. 9B may be used.

(V-ribbed belt)
V-ribbed belts of the following Examples 1 to 4 and Comparative Examples 1 to 4 were produced by the same method as in the above embodiment. The blending of the uncrosslinked rubber sheet for each compressed rubber layer is also shown in Table 1.

<Example 1>
As an uncrosslinked rubber sheet for a compressed rubber layer, EPDM (trade name: EP22, manufactured by JSR Corporation, ethylene content: 54 mass%, ethylidene nobornene (diene component) content: 4.5 mass%, Mooney viscosity: 27 ML _{1 + 4} (125 ° C. )) As a rubber component, with respect to 100 parts by mass of the rubber component, 65 parts by mass of carbon black as a reinforcing material (trade name: Diamond Black H) manufactured by Mitsubishi Chemical Co., Ltd., process oil as a softener (trade name manufactured by Nippon Sun Oil Co., Ltd.) : Samper 2280) 10 parts by mass, zinc oxide (3 types of zinc oxide manufactured by Hakusui Chemical Co., Ltd.) as a vulcanization accelerator, 1 part by mass of processing aid stearic acid (Stearic acid S50 manufactured by Shin Nippon Rika Co., Ltd.), 2 parts by mass of a benzimidazole anti-aging agent (trade name: NOCRACK MB, manufactured by Ouchi Shinsei Chemical Co., Ltd.), 2 parts by mass of a co-crosslinking agent (trade name: High Cross M, manufactured by Seiko Chemical Co., Ltd.) , Organic peroxide of cross-linking agent (trade name: Peroximon F40, purity 40% by mass, manufactured by NOF Corporation) 4.3 parts by mass (1.72 parts by mass of organic peroxide), sulfur of cross-linking agent (Nihon Kiboshi Kogyo Co., Ltd.) Product name: Seimi OT) 2 parts by mass, thiuram vulcanization accelerator having a thiocarbonyl group (Ouchi Shinsei Chemical Co., Ltd. product name: Noxeller TET) 1 part by mass, nylon short fiber (Asahi Kasei Nylon 6, 6 type T-5, fiber length: 1.0 mm, fiber diameter: 26 μm), kneaded with a Banbury mixer, and rolled with a calendar roll was used. In the uncrosslinked rubber sheet for the compressed rubber layer, the organic peroxide content is 0.81% by mass, the sulfur content is 0.94% by mass, and the thiuram vulcanization accelerator content is 0.00. 47% by mass, sulfur content / organic peroxide content 1.16, thiuram vulcanization accelerator content / organic peroxide content 0.58, and thiuram type The content of the vulcanization accelerator / the content of sulfur is 0.5.

As an uncrosslinked rubber sheet for the adhesive rubber layer, EPDM (trade name: EP33, manufactured by JSR Co., Ltd., ethylene content: 52 mass%, ethylidene nobornene (diene component) content: 8.1 mass%, Mooney viscosity: 28 ML _{1 + 4} (125 ° C. )) As a rubber component, with respect to 100 parts by mass of the rubber component, 40 parts by mass of reinforcing material carbon black (trade name: SEAST SO) manufactured by Tokai Carbon Co., Ltd., silica of reinforcing material (trade name manufactured by Evonik Co., Ltd .: Ultrasil VN3) ) 40 parts by weight, softener process oil (trade name: Sunper 2280, manufactured by Nippon Sun Oil Co., Ltd.), 15 parts by weight, vulcanization acceleration aid zinc oxide (3 types of zinc oxide, manufactured by Hakusui Chemical Co., Ltd.), processing aid 1 part by weight of stearic acid (Shinic acid S50, manufactured by Shin Nippon Rika Co., Ltd.), benzimidazole anti-aging agent (trade name: Nokrat, manufactured by Ouchi Shinsei Chemical Co., Ltd.) MB) 2 parts by mass, co-crosslinking agent (trade name: High Cloth M, manufactured by Seiko Chemical Co., Ltd.), 2 parts by mass, sulfur of the crosslinking agent (product name: Seimi OT, manufactured by Nihon Kiboshi Kogyo Co., Ltd.), and thiocarbonyl group 1 part by mass of a thiuram vulcanization accelerator (trade name: Noxeller TET, manufactured by Ouchi Shinsei Chemical Co., Ltd.) having kneading, kneading with a Banbury mixer, and rolling with a calender roll were used. The uncrosslinked rubber sheet for the adhesive rubber layer has a lower ethylene content of EPDM as the rubber component and higher ethylidene nobornene (diene component) content and Mooney viscosity than the uncrosslinked rubber sheet for the compressed rubber layer. Also, unlike the uncrosslinked rubber sheet for the compressed rubber layer, only sulfur as a crosslinking agent is blended and no organic peroxide is blended. On the other hand, the same thiocarbonyl as the uncrosslinked rubber sheet for the adhesive rubber layer A thiuram vulcanization accelerator having a group is blended.

  As a fabric material for the back reinforcing fabric, a woven fabric made of cotton / polyester blended fiber was used. As the twisted yarn for the core wire, a polyester fiber twisted yarn subjected to adhesion treatment was used.

  The V-ribbed belt of Example 1 had a belt length of 1115 mm, a belt width of 10.68 mm (3 ribs), a belt thickness of 4.3 mm, and a V-rib height of 2.0 mm.

<Example 2>
For the uncrosslinked rubber sheet for the compression rubber layer, a dithiocarbamate vulcanization accelerator having a thiocarbonyl group (trade name: Noxeller EZ, manufactured by Ouchi Shinsei Chemical Co., Ltd.) was blended in place of the thiuram vulcanization accelerator. A V-ribbed belt having the same configuration as that of Example 1 was used as Example 2 except for the above.

  In the uncrosslinked rubber sheet for the compressed rubber layer, the organic peroxide content is 0.81% by mass, the sulfur content is 0.94% by mass, and the thiuram vulcanization accelerator content is 0.00. 47% by mass, sulfur content / organic peroxide content 1.16, thiuram vulcanization accelerator content / organic peroxide content 0.58, and thiuram type The content of the vulcanization accelerator / the content of sulfur is 0.5.

<Example 3>
A V-ribbed belt having the same configuration as in Example 1 was used in Example 3 except that the uncrosslinked rubber sheet for the compression rubber layer was 1 part by mass with respect to 100 parts by mass of the rubber component.

  In this uncrosslinked rubber sheet for the compressed rubber layer, the content of the organic peroxide is 0.81% by mass, the content of sulfur is 0.47% by mass, and the content of the thiuram vulcanization accelerator is 0.00. 47 mass%, sulfur content / organic peroxide content is 0.58, thiuram vulcanization accelerator content / organic peroxide content is 0.58, and thiuram type The content of vulcanization accelerator / the content of sulfur is 1.

<Example 4>
A V-ribbed belt having the same configuration as that of Example 1 was used as Example 4 except that sulfur was not added to the uncrosslinked rubber sheet for the compressed rubber layer.

  In the uncrosslinked rubber sheet for the compressed rubber layer, the content of the organic peroxide is 0.82% by mass, the content of the thiuram vulcanization accelerator is 0.48% by mass, The content of the sulfur accelerator / the content of the organic peroxide is 0.59.

<Comparative Example 1>
A V-ribbed belt having the same configuration as that of Example 1 was used as Comparative Example 1 except that sulfur and a thiuram vulcanization accelerator were not blended in the uncrosslinked rubber sheet for the compression rubber layer.

<Comparative example 2>
A V-ribbed belt having the same configuration as that of Example 1 was used as Comparative Example 2 except that no organic peroxide was added to the uncrosslinked rubber sheet for the compressed rubber layer.

<Comparative Example 3>
About the uncrosslinked rubber sheet for the compression rubber layer, in place of the thiuram vulcanization accelerator, a guanidine vulcanization accelerator having no thiocarbonyl group (trade name: Noxeller DT manufactured by Ouchi Shinsei Chemical Co., Ltd.) was blended. A V-ribbed belt having the same configuration as that of Example 1 was used as Comparative Example 3 except for the above.

<Comparative example 4>
About uncrosslinked rubber sheet for compression rubber layer, instead of thiuram vulcanization accelerator, sulfenamide vulcanization accelerator having no thiocarbonyl group (trade name: Noxeller CZ-G manufactured by Ouchi Shinsei Chemical Co., Ltd.) A V-ribbed belt having the same structure as Example 1 was used as Comparative Example 4, except that

(Test evaluation method)
<Elongation at cutting>
Based on JISK6251, a crosslinked rubber composition sheet obtained by press-molding the uncrosslinked rubber sheet for the compressed rubber layer used in each of Examples 1 to 4 and Comparative Examples 1 to 4 under the conditions of 170 ° C. and 20 minutes. The elongation at break in the reverse direction corresponding to the belt length direction was measured. A dumbbell-shaped No. 3 test piece was used for the measurement.

<Loss factor>
Based on JISK6394, a crosslinked rubber composition sheet obtained by press molding the uncrosslinked rubber sheet for the compressed rubber layer used in each of Examples 1 to 4 and Comparative Examples 1 to 4 under the conditions of 170 ° C. and 20 minutes. The loss factor (tan δ) in the reverse direction corresponding to the belt length direction was measured at a test temperature of 100 ° C., a test frequency of 10 Hz, an average strain of 1.5%, and a strain amplitude of 1.0%.

<Heat resistance and flex resistance>
FIG. 10 shows a pulley layout of a belt running test machine 40 for evaluating heat resistance and bending resistance.

  This belt running test machine 40 includes four driven rib pulleys 41 each having a pulley diameter of 50 mm and four driven flat pulleys each having a pulley diameter of 50 mm and arranged in a square shape on the top and bottom and left and right sides. 42 and a drive rib pulley 43 having a pulley diameter of 60 mm. The upper two driven flat pulleys 42 are provided at the intermediate positions in the vertical direction of the upper and lower driven rib pulleys 41 in a region surrounded by four rectangular driven rib pulleys 41 arranged in a rectangular shape. The pulley 42 is provided below the lower driven rib pulley 41. The drive rib pulley 43 is provided below the lower driven flat pulley 42 at the intermediate position in the left-right direction of the driven rib pulley 41 and the driven flat pulley 42. No rotational load is applied to the driven rib pulley 41 and the driven flat pulley 42. The drive rib pulley 43 is configured to be movable in the vertical direction so that belt tension can be applied to the V-ribbed belt B. The V-ribbed belt B is wound around the belt running test machine 40 having the above configuration so that the V-rib side is in contact with the driven rib pulley 41 and the drive rib pulley 43 and the back side is in contact with the driven flat pulley 42.

  For each of the V-ribbed belts B of Examples 1 to 4 and Comparative Examples 1 to 4, the belt running tester 40 is set, and a downward load is applied to the drive rib pulley 43 so that a belt tension of 800 N is applied. Then, the drive rib pulley 43 was rotated at a rotational speed of 3300 rpm to run the belt. At this time, the temperature of the atmosphere is increased to 100 ° C., the state is maintained for 50 hours, the temperature is increased to 105 ° C., and the state is maintained for 50 hours. The operation of holding for 50 hours was repeated until the atmospheric temperature reached 130 ° C., and temperature control for holding 130 ° C. was performed after 300 hours when the atmospheric temperature reached 130 ° C.

  The belt running is periodically stopped, the V-ribbed belt B is visually inspected, and the belt running time until a crack is generated in the compressed rubber layer is recorded as the heat-resistant / flexible running life. The relative value was calculated with the flexural running life as 100.

<Abrasion resistance and adhesion resistance>
FIG. 11 shows a pulley layout of the belt running test machine 50 for wear resistance evaluation.

  The belt running test machine 50 includes a drive rib pulley 51 and a driven rib pulley 52 each having a pulley diameter of 60 mm provided on the left and right sides. A rotational load corresponding to 3.8 kW is applied to the driven rib pulley 52. The V-ribbed belt B is wound around the belt running test machine 50 having the above configuration so that the V-rib side is in contact with the drive rib pulley 51 and the back side is in contact with the driven rib pulley 52.

  About each V-ribbed belt B of Examples 1 to 4 and Comparative Examples 1 to 4, after measuring the mass, it is set on the belt running test machine 50, and also on the driven rib pulley 52 so that the belt tension is loaded. A dead weight of 1177N was loaded on the side, and the drive rib pulley 51 was rotated at a rotational speed of 3500 rpm and the belt was run for 24 hours, and then the mass was measured again.

  The wear rate was calculated by dividing the weight loss before and after running the belt by the mass before running the belt. The wear rate of Comparative Example 1 was taken as 100, and the relative value was calculated as wear resistance. Further, the presence or absence of adhesion on the surface of the compressed rubber layer after running the belt was visually confirmed.

(Test evaluation results)
Tables 2-4 show the test results.

  According to the above results, in Examples 1 to 4 in which a compression rubber layer was formed from a rubber composition that was blended with EPDM and a vulcanization accelerator having a thiocarbonyl group and crosslinked with an organic peroxide, The rubber composition forming the compressed rubber layer has an excellent balance of elongation at break and loss factor, and therefore has excellent heat resistance and bending resistance while maintaining high wear resistance and adhesion resistance in the V-ribbed belt. I understand.

  On the other hand, in Comparative Example 1 in which a vulcanization accelerator having a thiocarbonyl group was not blended, the rubber composition forming the compressed rubber layer had a small elongation at break and a loss factor. It can be seen that the heat resistance and bending resistance are inferior compared with each other. This is presumably because the rubber composition forming the compressed rubber layer has a small elongation at the time of cutting, so that cracks are likely to occur there.

  In Comparative Example 2 crosslinked with sulfur, the rubber composition forming the compressed rubber layer has a large elongation at break and a loss factor, and the V-ribbed belt may be inferior in heat resistance and flex resistance as compared with Examples 1 to 4. I understand. This is presumably because the rubber composition forming the compressed rubber layer has a large loss factor, and cracks are likely to occur there.

  In Comparative Examples 3 and 4 in which a vulcanization accelerator other than a vulcanization accelerator having a thiocarbonyl group was blended, the loss coefficient of the rubber composition forming the compression rubber layer was lower than that in Comparative Example 2, and in the V-ribbed belt, Compared to Comparative Example 2, it can be seen that the heat resistance and bending resistance are improved. However, since the abrasion resistance and the adhesion resistance are inferior, the practicality as a V-ribbed belt is poor.

  INDUSTRIAL APPLICATION This invention is useful about a friction transmission belt, its manufacturing method, and a belt transmission apparatus.

B V-ribbed belt (V belt, flat belt)
11 Compressed rubber layer 11a Surface rubber layer

Claims (15)

A friction transmission belt having a rubber layer constituting a pulley contact portion on the inner circumference side of the belt,
The rubber layer includes a rubber component mainly composed of an ethylene-α-olefin elastomer, a vulcanization accelerator having a thiocarbonyl group, and a friction transmission formed by a rubber composition crosslinked with an organic peroxide. belt. In the friction transmission belt according to claim 1,
The friction transmission belt, wherein the vulcanization accelerator having a thiocarbonyl group includes a thiuram vulcanization accelerator or a dithiocarbamate vulcanization accelerator. In the friction transmission belt according to claim 1 or 2,
A friction transmission belt in which the content of the vulcanization accelerator having a thiocarbonyl group in the uncrosslinked rubber composition before formation of the rubber layer is 0.1 to 2.2% by mass. In the friction transmission belt according to any one of claims 1 to 3,
A friction transmission belt in which the content of the organic peroxide in the uncrosslinked rubber composition before formation of the rubber layer is 0.2 to 6.5 mass%. The friction transmission belt according to any one of claims 1 to 4,
Ratio of content of vulcanization accelerator having thiocarbonyl group to content of organic peroxide in uncrosslinked rubber composition before formation of rubber layer (content of vulcanization accelerator having thiocarbonyl group) / Content of organic peroxide) is 0.1 to 1.0. In the friction transmission belt according to claim 5,
A friction transmission belt in which the content of the vulcanization accelerator having the thiocarbonyl group in the uncrosslinked rubber composition before formation of the rubber layer is less than the content of the organic peroxide. The friction transmission belt according to any one of claims 1 to 6,
A friction transmission belt in which the rubber composition forming the rubber layer is also cross-linked by sulfur. The friction transmission belt according to claim 7,
A friction transmission belt in which the content of sulfur in the uncrosslinked rubber composition before formation of the rubber layer is 0.1 to 1.7% by mass. In the friction transmission belt according to claim 7 or 8,
Ratio of content of vulcanization accelerator having thiocarbonyl group to content of sulfur in uncrosslinked rubber composition before formation of rubber layer (content of vulcanization accelerator having thiocarbonyl group / sulfur A friction transmission belt having a content of 0.1 to 6.0. The friction transmission belt according to claim 9,
A friction transmission belt in which the content of the vulcanization accelerator having a thiocarbonyl group in the uncrosslinked rubber composition before formation of the compressed rubber layer 11 is the same as or less than the content of sulfur. The friction transmission belt according to any one of claims 7 to 10,
The ratio of the sulfur content to the organic peroxide content (sulfur content / organic peroxide content) in the uncrosslinked rubber composition before formation of the rubber layer is 0.1-2. A friction transmission belt that is zero. The friction transmission belt according to claim 11,
A friction transmission belt in which the content of sulfur in the uncrosslinked rubber composition before formation of the rubber layer is larger than the content of the organic peroxide.   A belt transmission device in which the friction transmission belt according to any one of claims 1 to 12 is wound around a plurality of pulleys.   The method for producing a friction transmission belt according to any one of claims 1 to 12, wherein a rubber component mainly composed of an ethylene-α-olefin elastomer is blended with a vulcanization accelerator having a thiocarbonyl group, and a crosslinking agent. A method for producing a friction transmission belt in which an organic peroxide is blended to produce an uncrosslinked rubber for the rubber layer. In the manufacturing method of the friction transmission belt described in Claim 14,
A method for producing a friction transmission belt, wherein sulfur is further added to the rubber component as a crosslinking agent.