JP6348136B2 - Friction transmission belt and manufacturing method thereof - Google Patents

Description

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

  Frictional power transmission belts in which ultra high molecular weight polyethylene particles are dispersed and exposed on the pulley contact surface are known. For example, Patent Documents 1 to 3 disclose that a compressed rubber layer of a V-ribbed belt is formed from a rubber composition in which ultra high molecular weight polyethylene particles are blended.

JP 2007-070592 A JP 2007-170454 A JP 2007-170587 A

  The subject of this invention is suppressing the fall of the power transmission capability by the slip at the time of flooding of a friction transmission belt.

The present invention is a friction transmission belt having a rubber layer constituting a pulley contact surface, wherein hollow resin particles in which molecular chains of polymers constituting the particles are crosslinked are dispersed on the pulley contact surface of the rubber layer. Exposed.

The present invention relates to a method for producing a friction transmission belt having a rubber layer constituting a pulley contact surface, wherein hollow resin particles in which molecular chains of polymers constituting the particles are crosslinked and exposed are exposed on the pulley contact surface. The rubber layer is formed as described above.

  According to the present invention, the hollow resin particles cross-linked on the pulley contact surface are dispersed and exposed, so that it is possible to suppress a decrease in power transmission capability due to slipping when wet.

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. 6 is a perspective view of a V-ribbed belt according to Embodiment 3. FIG. It is sectional drawing for one V rib of the V ribbed belt which concerns on Embodiment 3. FIG. 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 a belt running test machine. It is a SEM observation photograph which shows the form of the pulley contact surface after the belt running of the V-ribbed belt of Example 2. It is a SEM observation photograph which shows the form of the pulley contact surface after the belt running of the V-ribbed belt of the comparative example 3.

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

(Embodiment 1)
1 and 2 show a V-ribbed belt B (friction 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. For example, the V-ribbed belt B according to the first embodiment has 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 includes a V-ribbed belt main body 10 configured as a triple layer of a compression rubber layer 11 on the belt inner peripheral side, an intermediate adhesive rubber layer 12 and a stretched rubber layer 13 on the belt outer peripheral side. Yes. 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 compressed rubber layer 11 is, for example, 1.0 to 3.6 mm, the thickness of the adhesive rubber layer 12 is, for example, 1.0 to 2.5 mm, and the thickness of the stretched rubber layer 13 is, for example, 0.4. ~ 0.8 mm. A configuration in which a back reinforcing cloth is provided instead of the stretched rubber layer 13 may be used.

  The compressed rubber layer 11 is provided such that a plurality of V ribs 15 hang down to the belt inner peripheral side. Each of the plurality of V ribs 15 is 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 11 constitute pulley contact surfaces as power transmission surfaces. 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 obtained by heating and adding an uncrosslinked rubber composition kneaded by mixing various compounding agents containing crosslinked hollow resin particles (hereinafter also referred to as “crosslinked hollow resin particles”) into the rubber component. It is formed of a rubber composition in which a rubber component is cross-linked by being pressed. Therefore, the rubber composition forming the compressed rubber layer 11 contains a crosslinked rubber component and various compounding agents including crosslinked hollow resin particles dispersed in the rubber component. According to the V-ribbed belt B according to Embodiment 1, the compressed rubber layer 11 constituting the pulley contact surface is formed of a rubber composition containing crosslinked hollow resin particles, and the crosslinked hollow resin particles are dispersed on the pulley contact surface. Since it is exposed, as shown in the below-mentioned Example, the fall of the power transmission capability by the slip at the time of flooding can be suppressed.

  Examples of the rubber component of the rubber composition forming the compressed rubber layer 11 include ethylene-propylene-diene terpolymer (hereinafter referred to as “EPDM”), ethylene-propylene copolymer (EPM), ethylene-butene copolymer (EDM), Examples include ethylene-α-olefin elastomers such as ethylene-octene copolymer (EOM); chloroprene rubber (CR); chlorosulfonated polyethylene rubber (CSM); hydrogenated acrylonitrile rubber (H-NBR). As the rubber component, it is preferable to use a blend of one or more of these, preferably an ethylene-α-olefin elastomer, and more preferably EPDM.

  Examples of the resin constituting the crosslinked hollow resin particles include polyolefin resin, polyamide resin, polyester resin, polyurethane resin, polytetrafluoroethylene resin, and the like. Of these, one or two or more kinds of crosslinked hollow resin particles are preferably used as the crosslinked hollow resin particles, and crosslinked polyolefin resin particles are more preferably used.

  In the case of the crosslinked hollow polyolefin resin particles, examples of the polyolefin constituting the hollow polyolefin resin particles include homopolymers such as polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene; ethylene and propylene, 1- And copolymers with α-olefins such as butene, 1-hexene, 1-octene, 4-methyl-1-pentene, and the like. Of these, one or two or more of the crosslinked hollow polyolefin resin particles are preferably used, and polyethylene homopolymer particles are more preferably used.

  In addition, the crosslinked hollow polyolefin resin particles have an average molecular weight (weight average molecular weight) from the viewpoint of enhancing the wear resistance of the compressed rubber layer 11 constituting the pulley contact surface and suppressing the decrease in power transmission capability due to slippage when wet. The number average molecular weight) is preferably a crosslinked hollow resin particle of ultrahigh molecular weight polyolefin having a molecular weight of 500,000 or more, and the average molecular weight (weight average molecular weight, number average molecular weight) is preferably 1,000,000 or more, more preferably 1.8 million. From the viewpoint of enhancing the bending fatigue resistance, it is preferably 6 million or less, more preferably 3.5 million or less, and further preferably 3 million or less.

  The average particle diameter of the crosslinked hollow resin particles is preferably 10 μm or more, more preferably from the viewpoint of enhancing the wear resistance of the compressed rubber layer 11 constituting the pulley contact surface and suppressing the decrease in power transmission capability due to slippage when wet. Is preferably not more than 200 μm, more preferably not more than 170 μm, still more preferably not more than 150 μm, from the viewpoint of enhancing the bending fatigue resistance. This average particle diameter is obtained by arithmetically averaging 50 to 100 particle diameters (maximum outer diameter) actually measured in consideration of an enlargement magnification from a scanning electron microscope observation photograph of the crosslinked hollow resin particles.

  The particle size distribution of the cross-linked hollow resin particles is preferably from 100 to 150 μm from the viewpoint of enhancing the wear resistance of the compressed rubber layer 11 constituting the pulley contact surface and suppressing the decrease in power transmission capability due to slippage when wet. Is in the range of 70 mass% or more, more preferably 80 mass% or more, still more preferably 90 mass% or more.

  The shape of the cross-linked hollow resin particles is preferably close to a sphere from the viewpoint of enhancing the wear resistance of the compressed rubber layer 11 constituting the pulley contact surface and suppressing the decrease in power transmission capability due to slippage when wet. The aspect ratio obtained by dividing the maximum outer diameter of the resin particles by the minimum outer diameter is preferably 2.00 or less, more preferably 1.50 or less, and still more preferably 1.30 or less. This aspect ratio is obtained by arithmetically averaging 50 to 100 maximum outer diameters measured by taking the magnification into consideration from an observation photograph of a cross-linked hollow resin particle with a scanning electron microscope and taking the magnification ratio into consideration. . When the cross-linked hollow resin particles are formed by aggregation of spherical particles having a particle diameter of 10 to 50 μm in the form of tufts, the spherical particles are fused and integrated by heating during production. It is preferably formed in a spherical or elliptical shape.

  The intrinsic viscosity [η] measured in the decalin at 135 ° C. of the crosslinked hollow resin particles increases the wear resistance of the compressed rubber layer 11 constituting the pulley contact surface and suppresses the decrease in power transmission capability due to slipping when wet. From the viewpoint, it is preferably 5 dl / g or more, and from the viewpoint of enhancing bending fatigue resistance, it is preferably 50 dl / g or less, more preferably 30 dl / g or less.

  The melting point of the cross-linked hollow resin particles is preferably 125 ° C. or more, more preferably from the viewpoint of enhancing the wear resistance of the compressed rubber layer 11 constituting the pulley contact surface and suppressing the decrease in power transmission capability due to slippage when wet. It is 130 ° C. or higher, and preferably 145 ° C. or lower. This melting point is determined by differential scanning calorimetry (DSC).

  The content of the cross-linked hollow resin particles in the rubber composition forming the compressed rubber layer 11 increases the wear resistance of the compressed rubber layer 11 constituting the pulley contact surface and suppresses a decrease in power transmission capability due to slipping when wet. From the viewpoint, it is preferably 20 parts by mass or more, more preferably 50 parts by mass or more, and still more preferably 70 parts by mass or more, with respect to 100 parts by mass of the rubber component, and from the viewpoint of improving the bending fatigue resistance, 100 parts by mass or less, more preferably 90 parts by mass or less.

  The cross-linked hollow resin particle has a polymer molecular chain that is cross-linked and has a hollow portion. Such crosslinked hollow resin particles can be prepared by irradiating the uncrosslinked solid resin particles with radiation to perform a crosslinking treatment. The hollow portion is formed during this process. When uncrosslinked solid resin particles are irradiated with radiation, the molecular chains of the polymer are broken and cross-linked, and as a result, the molecular chains are bonded at the cross-linking points, and at that time, gas is generated to form a hollow portion. It is considered a thing. Examples of radiation include α-rays, β-rays, γ-rays, electron beams, ions, and the like, and electron beams or γ-rays are preferably used. The irradiation dose of radiation is preferably 50 kGy or more, more preferably 100 kGy or more, and preferably 700 kGy or less, more preferably 500 kGy or less.

  The rubber composition for forming the compressed rubber layer 11 is one or two of crosslinked solid resin particles, uncrosslinked hollow resin particles, and uncrosslinked solid resin particles in addition to the crosslinked hollow resin particles. You may contain the above.

  Examples of the compounding agent include reinforcing materials such as carbon black, fillers, processing aids, vulcanization aids, crosslinking 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. It is preferable to use one or more of these reinforcing materials. The content of the reinforcing material is preferably 30 to 60 parts by mass with respect to 100 parts by mass of the rubber component.

  Examples of the filler include calcium carbonate and layered silicate. It is preferable to use one or both of the fillers. The content of the filler is preferably 10 to 60 parts by mass with respect to 100 parts by mass of the rubber component.

  Examples of the layered silicate of the filler include smectite group, vermulite group, and kaolin group. Examples of the smectite group include montmorillonite, beidellite, saponite, and hectorite. Examples of the vermulite family include 3 octahedral vermulites, 2 octahedral vermulites, and the like. Examples of the kaolin family include kaolinite, dickite, halloysite, lizardite, amesite, and chrysotile. It is preferable to use 1 type, or 2 or more types of these for layered silicate. The content of the layered silicate in the rubber composition forming the compressed rubber layer 11 is preferably 10 to 50 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. The content of the processing aid in the rubber composition forming the compressed rubber layer 11 is preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the rubber component.

  Examples of the vulcanization 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. The content of the vulcanization aid is, for example, 1 to 10 parts by mass with respect to 100 parts by mass of the rubber component.

  Examples of the crosslinking agent include organic peroxides and sulfur. The crosslinking agent may be an organic peroxide used alone, sulfur may be used alone, or both of them may be used in combination. In the case of an organic peroxide, the amount of the crosslinking agent is, for example, 0.5 to 8 parts by mass with respect to 100 parts by mass of the rubber component. 5-4 parts by mass.

  Examples of the co-crosslinking agent include trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, triallyl isocyanurate, liquid polybutadiene, N, N′-m-phenylenebismaleimide and the like. It is preferable to use one or more of these co-crosslinking agents. The content of the co-crosslinking agent in the rubber composition forming the compressed rubber layer 11 is preferably 0.5 to 7 parts by mass with respect to 100 parts by mass of the rubber component.

  The rubber composition forming the compressed rubber layer 11 preferably does not contain short fibers. However, short fibers may be contained as long as the effect of improving wear resistance is not impaired.

  The adhesive rubber layer 12 is configured in a strip shape having a horizontally long cross section. The stretch rubber layer 13 is also formed in a strip shape having a horizontally long cross section. The surface of the stretch rubber layer 13 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.

  Each of the adhesive rubber layer 12 and the stretched rubber layer 13 is formed of a rubber composition that is crosslinked by heating and pressing an uncrosslinked rubber composition in which various compounding agents are blended in a rubber component. Therefore, each of the adhesive rubber layer 12 and the stretched rubber layer 13 contains a crosslinked rubber component and various compounding agents. The stretch rubber layer 13 is preferably formed of a rubber composition that is slightly harder than the adhesive rubber layer 12 from the viewpoint of suppressing the occurrence of sticking by contact with the flat pulley.

  Examples of the rubber component of the rubber composition forming the adhesive rubber layer 12 and the stretch rubber layer 13 include ethylene-α-olefin elastomer, chloroprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), hydrogenated acrylonitrile rubber ( H-NBR) and the like, and the same rubber component as that of the compressed rubber layer 11 is preferable.

  Examples of the compounding agent include a reinforcing material such as carbon black, a filler, a processing aid, a vulcanization aid, a crosslinking agent, a co-crosslinking agent, and the like, as in the case of the compressed rubber layer 11.

  The compressed rubber layer 11, the adhesive rubber layer 12, and the stretched rubber layer 13 may be formed of a rubber composition having the same composition or a rubber composition having a different composition.

  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 in the rubber component and kneaded by a kneader such as a kneader or a Banbury mixer, and the resulting uncrosslinked rubber composition is formed into a sheet by calendar molding or the like. To form an uncrosslinked rubber sheet 11 ′ for the compressed rubber layer. Crosslinked hollow resin particles are blended in the uncrosslinked rubber sheet 11 'for the compressed rubber layer. The crosslinked hollow resin particles are prepared in advance by irradiating the uncrosslinked solid resin particles with radiation before blending into the uncrosslinked rubber sheet 11 '. The crosslinked hollow resin particles before blending may have a form in which spherical particles having a particle diameter of 10 to 50 μm are aggregated in a tuft shape.

  Similarly, uncrosslinked rubber sheets 12 'and 13' for the adhesive rubber layer and the stretch 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 13 ′ for an extended rubber layer and an uncrosslinked rubber sheet for an 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 11 'for compression rubber layers is wound in order, and uncrosslinked slab S' is formed. At this time, the uncrosslinked rubber sheets 11 ′, 12 ′, and 13 ′ are wound so that the row direction 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. When the cross-linked hollow resin particles are in the form before compounding, spherical particles having a particle diameter of 10 to 50 μm are aggregated in tufts, the spherical particles are fused and integrated by heating to form a spherical shape. It is preferable to form an ellipsoid. 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 °.

(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 compressed rubber layer 11 includes a surface rubber layer 11a and a core rubber layer 11b. The surface rubber layer 11a is provided in a layer shape along the entire surface of the V-rib 15, and the surfaces of the plurality of V-ribs 15 in the surface rubber layer 11a constitute a pulley contact surface as a power transmission surface. The thickness of the surface rubber layer 11a is, for example, 50 to 500 μm. The core rubber layer 11b is provided inside the surface rubber layer 11a and constitutes a portion other than the surface rubber layer 11a in the compressed rubber layer 11.

  The surface rubber layer 11a is formed of a rubber composition containing a crosslinked rubber component and various compounding agents including crosslinked hollow resin particles dispersed in the rubber component, like the compressed rubber layer 11 in the first embodiment. Yes.

  The core rubber layer 11b is formed of a rubber composition containing a crosslinked rubber component and various compounding agents. The rubber composition forming the core rubber layer 11b may contain cross-linked hollow resin particles, and the content thereof relative to 100 parts by mass of the rubber component is that of the cross-linked hollow resin particles in the rubber composition forming the surface rubber portion 11a. The content is preferably less than the content relative to 100 parts by mass of the rubber component. However, from the viewpoint of enhancing the bending fatigue resistance, the rubber composition forming the core rubber layer 11b preferably does not substantially contain the crosslinked hollow resin particles, and specifically, with respect to 100 parts by mass of the rubber component. Their content is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, still more preferably 2 parts by mass or less, and most preferably 0 parts by mass. The rubber composition forming the core rubber layer 11b may be the same as the rubber composition forming the adhesive rubber layer 12 or the stretch rubber layer 13.

  According to the V-ribbed belt B according to the second embodiment configured as described above, the surface rubber 11a constituting the pulley contact surface is formed of a rubber composition containing crosslinked hollow resin particles, and the crosslinked hollow resin particles are formed on the pulley contact surface. Since they are exposed in a dispersed manner, as shown in the examples described later, it is possible to suppress a decrease in power transmission capability due to slipping when the water is wet.

  In order to manufacture the V-ribbed belt B according to the second embodiment, uncrosslinked rubber sheets 11a 'and 11b' for the surface rubber layer and the core rubber layer of the compressed rubber layer 11 are produced. Crosslinked hollow resin particles are blended in the uncrosslinked rubber sheet 11a 'for the surface rubber layer. Next, as shown in FIG. 12, the uncrosslinked rubber sheet 13 ′ for the stretched 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 11b ′ for the core rubber layer in the compressed rubber layer 11, and the uncrosslinked rubber sheet 11a ′ 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.

(Embodiment 3)
14 and 15 show a V-ribbed belt B according to the third 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 third embodiment, the compressed rubber layer 11 has a surface rubber layer 11a and a core rubber layer 11b. The surface rubber layer 11a is formed 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 11a is, for example, 50 to 500 μm. The core rubber layer 11b is made of solid rubber, is provided inside the surface rubber layer 11a, and constitutes a portion of the compressed rubber layer 11 other than the surface rubber layer 11a.

  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 11a is formed of a rubber composition containing a crosslinked rubber component and various compounding agents including crosslinked hollow resin particles dispersed in the rubber component, like the compressed rubber layer 11 in the first embodiment. Yes. In addition, since the surface rubber layer 11a is 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.

  Since the surface rubber layer 11a 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.

  The core rubber layer 11b is formed of a rubber composition containing a crosslinked rubber component and various compounding agents. The rubber composition for forming the core rubber layer 11b may be the same as the rubber composition for forming the surface rubber layer 11a excluding the hollow portion and the concave hole 16.

  The rubber composition forming the core rubber layer 11b may contain cross-linked hollow resin particles, and the content thereof relative to 100 parts by mass of the rubber component is that of the cross-linked hollow resin particles in the rubber composition forming the surface rubber portion 11a. The content is preferably less than the content relative to 100 parts by mass of the rubber component. However, from the viewpoint of enhancing the bending fatigue resistance, the rubber composition forming the core rubber layer 11b preferably does not substantially contain the crosslinked hollow resin particles, and specifically, with respect to 100 parts by mass of the rubber component. Their content is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, still more preferably 2 parts by mass or less, and most preferably 0 parts by mass. The rubber composition forming the core rubber layer 11b may be the same as the rubber composition forming the adhesive rubber layer 12 or the stretch rubber layer 13.

  According to the V-ribbed belt B according to Embodiment 3 having the above configuration, the surface rubber 11a constituting the pulley contact surface is formed of a rubber composition containing crosslinked hollow resin particles, and the crosslinked hollow resin particles are formed on the pulley contact surface. Since they are exposed in a dispersed manner, as shown in the examples described later, it is possible to suppress a decrease in power transmission capability due to slipping when the water is wet.

  To manufacture the V-ribbed belt B according to the third embodiment, uncrosslinked rubber sheets 11a 'and 11b' for the surface rubber layer and the core rubber layer of the compressed rubber layer 11 are produced. In addition to the crosslinked hollow resin particles, hollow particles and / or a foaming agent are blended in the uncrosslinked rubber sheet 11a 'for the surface rubber layer. Next, by a method similar to that of the second embodiment (see FIGS. 12 and 13), an uncrosslinked rubber sheet 13 ′ for an extended rubber layer, and an adhesive rubber are formed on a rubber sleeve 25 covered on a cylindrical drum 24 having a smooth surface. 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 11b ′ for the core rubber layer in the compressed rubber layer 11, and the uncrosslinked rubber sheet 11a ′ for the surface rubber layer are wound in order to form an uncrosslinked slab S ′. Then, a cylindrical belt slab S 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 to third embodiments, the rubber composition forming the rubber layer constituting the pulley contact surface is configured to include the crosslinked hollow resin particles. However, the invention is not particularly limited thereto. The rubber composition forming the rubber layer does not contain cross-linked hollow resin particles, but the cross-linked hollow resin particles may be dispersed and attached to the surface of the rubber composition. Such a configuration is obtained by dispersing and adhering the crosslinked hollow resin particles on the molding surface of the mold for molding the rubber layer constituting the pulley contact surface and / or the surface of the uncrosslinked rubber composition in contact therewith. be able to.

  In the first to third embodiments, the V-ribbed belt B is shown. However, the present invention is not particularly limited to this, and if it is a friction transmission belt, for example, a pulley contact surface on the belt inner peripheral side as shown in FIG. 16A is used. It may be a low edge type V-belt B having a compression rubber layer 11 to be formed, or a flat belt B having an inner rubber layer 17 constituting a pulley contact surface on the belt inner peripheral side as shown in FIG. 16B. May be.

(V-ribbed belt)
V-ribbed belts of Examples 1 to 3 and Comparative Examples 1 to 3 below were produced. Each configuration is also shown in Table 1.

<Example 1>
EPDM as a rubber component is put into a chamber of a closed Banbury mixer and masticated. Then, 100 parts by mass of this rubber component, 2 parts by mass of ISAF carbon black, and a crosslinked hollow polyethylene resin particle of ultrahigh molecular weight polyethylene (1) 80 parts by mass, silica 40 parts by mass, layered silicate (bentonite) 40 parts by mass, calcium carbonate 5 parts by mass, hollow particles 2.7 parts by mass, stearic acid 0.5 parts by mass, zinc oxide 5 parts by mass, Charge and knead 8 parts by mass (3.2 parts by mass) of an organic peroxide crosslinking agent having a purity of 40% by mass and 2 parts by mass of a co-crosslinking agent, and use the resulting uncrosslinked rubber composition to compress rubber. A V-ribbed belt having the same structure as that of the third embodiment in which the surface rubber layer was formed was produced.

  Here, as cross-linked hollow polyethylene resin particles of ultra-high molecular weight polyethylene, a trade name: Hi-Zex Million 240S (average molecular weight: 2 million, average particle diameter: 120 μm) manufactured by Mitsui Chemicals Co., Ltd. was irradiated with an electron beam at an irradiation dose of 200 kGy. What formed the hollow part by performing the crosslinking process was used.

  The core rubber layer of the compression rubber layer, the adhesive rubber layer, and the back rubber layer were formed of other rubber compositions containing EPDM as a rubber component. The core wire was composed of a twisted yarn made of polyethylene terephthalate fiber. Further, the surface rubber layer of the compressed rubber layer was subjected to surface polishing. The belt length was 900 mm, the belt width was 21.36 mm, the belt thickness was 4.3 mm, and the number of ribs was six.

<Example 2>
As cross-linked hollow polyethylene resin particles of ultra-high molecular weight polyethylene, trade name: Sunfine UH-850 (average molecular weight: 2,200,000, average particle size: 150 μm) manufactured by Asahi Kasei Chemicals Co., Ltd. is irradiated with an electron beam at an irradiation dose of 200 kGy. A V-ribbed belt having the same configuration as that of Example 1 was produced except that the crosslinked hollow polyethylene resin particles (2) having a hollow portion formed by the treatment were used.

<Example 3>
A V-ribbed belt having the same configuration as that of Example 1 except that HAF carbon black is used instead of ISAF carbon black and no hollow particles are used, and the same configuration as that of Embodiment 2 above, is prepared. It was.

<Comparative Example 1>
In place of the ultra-high molecular weight polyethylene crosslinked hollow polyethylene resin particles (1), trade name: Mitsuko Chemical Co., Ltd., which is not subjected to crosslinking treatment by electron beam irradiation: Hi-Zex Million 240S, that is, uncrosslinked solid polyethylene resin particles 50 parts by mass with respect to 100 parts by mass of the rubber component, 2.6 parts by mass of the hollow particles with respect to 100 parts by mass of the rubber component, and 7.3 parts by mass of the foaming agent with respect to 100 parts by mass of the rubber component. Except for this, a V-ribbed belt having the same configuration as that of Example 1 was produced and used as Comparative Example 1.

<Comparative example 2>
A V-ribbed belt having the same configuration as Comparative Example 1 was prepared except that 70 parts by mass of uncrosslinked solid polyethylene resin particles were used with respect to 100 parts by mass of the rubber component and no foaming agent was used. It was.

<Comparative Example 3>
The same configuration as Comparative Example 2 except that 100 parts by mass of uncrosslinked solid polyethylene resin particles was used with respect to 100 parts by mass of rubber component and 3.1 parts by mass of hollow particles with respect to 100 parts by mass of rubber component. A V-ribbed belt was produced and used as Comparative Example 3.

(Test evaluation method)
FIG. 17 shows a pulley layout of the belt running test machine 40.

  This belt running test machine 40 is provided with a drive pulley 41 that is a zinc-plated rib pulley having a pulley diameter of 140 mm at the lowest position, and a first driven pulley 42 (air conditioner) that is a rib pulley having a pulley diameter of 100 mm diagonally upward to the right. Pulley), and a second driven pulley 43 (alternator pulley), which is a rib pulley having a pulley diameter of 60 mm, is provided obliquely to the left of the drive pulley 41 and the first driven pulley 42. Further, the first driven pulley 42 An idler pulley 44, which is a flat pulley having a pulley diameter of 95 mm, is provided on the left side. In this belt running test machine 40, the V rib side of the V-ribbed belt B is in contact with the drive pulley 41, which is a rib pulley, and the first and second driven pulleys 42, 43, and the back side is in contact with an idler pulley 44, which is a flat pulley. Then, it is configured to be wound around.

  About each of Examples 1-3 and Comparative Examples 1-3, it winds around each pulley of the belt running test machine 50, positions the idler pulley 44 so that the belt tension of 400 N is loaded, and the first and second A load (first driven pulley 42: 1.5 MPa, second driven pulley 43: 20A) is applied to the driven pulleys 42 and 43, and the driving pulley 41 is rotated at a rotational speed of 750 ± 120 rpm under an ambient temperature of 25 ° C. The belt was run. And 10 ml of water was dripped at the belt winding start part of the drive pulley 41, and the presence or absence of the stop of belt running by slip was confirmed.

(Test results)
Table 1 shows the test results. According to this, in Examples 1 to 3, where the crosslinked hollow polyethylene particles were dispersed and exposed on the pulley contact surface, the belt running did not stop, but the uncrosslinked solid polyethylene particles were dispersed and exposed on the pulley contact surface. In Comparative Examples 1 to 3, belt running stopped. From this, it can be seen that Examples 1 to 3, in which the crosslinked hollow polyethylene particles are dispersed and exposed on the pulley contact surface, have a high effect of suppressing a decrease in power transmission capability due to slipping when wet.

  FIG. 18A is an SEM observation photograph of the pulley contact surface after running the belt of Example 2. 18B is a SEM observation photograph of the pulley contact surface after running the belt of Comparative Example 3. FIG. According to these photographs, in Example 2 in FIG. 18A, hollow portions are observed in the resin particles exposed on the pulley contact surface, whereas in Comparative Example 3 in FIG. 18B, the resin particles exposed on the pulley contact surface are A hollow part is not recognized. From these things, in Examples 1-3, it is thought that the drainage effect by the hollow part of the resin particle exposed to the pulley contact surface and the driving effect by the edge of the hollow part engaging the pulley are obtained. .

  The present invention is useful in the technical field of friction transmission belts and manufacturing methods thereof.

B V-ribbed belt, V-belt, flat belt (friction drive belt)
11 Compression rubber layer 11a Surface rubber layer 17 Inner rubber layer

Claims (6)

A friction transmission belt having a rubber layer constituting a pulley contact surface,
A friction transmission belt in which hollow resin particles in which molecular chains of polymers constituting the particles are cross-linked are dispersed and exposed on the pulley contact surface of the rubber layer. In the friction transmission belt according to claim 1,
A friction transmission belt in which the rubber layer is formed of a rubber composition containing a crosslinked rubber component and the hollow resin particles. In the friction transmission belt according to claim 2,
The friction transmission belt whose content of the said hollow resin particle in the said rubber composition is 20-100 mass parts with respect to 100 mass parts of said rubber components. In the friction transmission belt according to any one of claims 1 to 3,
A friction transmission belt in which the hollow resin particles are polyolefin resin particles. A method of manufacturing a friction transmission belt having a rubber layer constituting a pulley contact surface,
A method for producing a friction transmission belt, wherein the rubber layer is formed on the pulley contact surface so that hollow resin particles in which molecular chains of the polymers constituting the particles are cross-linked are dispersed and exposed. In the manufacturing method of the friction transmission belt according to claim 5,
A method for producing a friction transmission belt, wherein the hollow resin particles are prepared by irradiating uncrosslinked solid resin particles with radiation.