CN107532681B

CN107532681B - Transmission belt

Info

Publication number: CN107532681B
Application number: CN201680023463.7A
Authority: CN
Inventors: 小林正吾; 中山铁平; 土屋大树; 奥野茂树; 橘博之
Original assignee: Bando Chemical Industries Ltd
Current assignee: Bando Chemical Industries Ltd
Priority date: 2015-04-24
Filing date: 2016-04-21
Publication date: 2020-11-06
Anticipated expiration: 2036-04-21
Also published as: WO2016170795A1; CN107532681A

Abstract

The present invention provides a transmission belt that satisfies a plurality of required characteristics at the same time. The belt (B) is a belt wound around a pulley to transmit power. The transmission belt has a layer composed of a rubber composition containing cellulose-based ultrafine fibers and short fibers (16) having an average diameter of 1 [ mu ] m or more.

Description

Transmission belt

Technical Field

The present invention relates to a transmission belt.

Background

Short fibers are blended in the rubber composition constituting the rubber layer of the transmission belt. For example, patent document 1 discloses that at least the compression layer of the v-ribbed belt is made of a rubber composition containing carbon black and short fibers.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2014-167347

The transmission belt is required to have various properties such as wear resistance, friction coefficient, and inhibition of adhesive wear. When carbon black and short fibers are blended in a rubber composition constituting a belt for reinforcement, if some properties are satisfied by adjusting the blending amount, other properties tend to be deteriorated.

Disclosure of Invention

Accordingly, an object of the present invention is to provide a transmission belt capable of satisfying a plurality of required characteristics at the same time.

The present invention is a transmission belt wound around a pulley to transmit power, comprising a layer made of a rubber composition containing cellulose-based microfine fibers and short fibers having an average diameter of 1 μm or more.

According to the present invention, since the layer is made of the rubber composition containing the cellulose-based microfiber and other short fibers, the transmission belt can satisfy a variety of required characteristics at the same time.

Drawings

Fig. 1 is a perspective view schematically showing an example of the v-ribbed belt according to embodiments 1 and 2.

Fig. 2 is a cross-sectional view of a main portion of the v-ribbed belts according to embodiments 1 and 2.

Fig. 3 is a first explanatory view showing a method of manufacturing the v-ribbed belt according to embodiments 1 and 2.

Fig. 4 is a second explanatory view showing a method of manufacturing the v-ribbed belt according to embodiments 1 and 2.

Fig. 5 is a third explanatory view showing a method of manufacturing the v-ribbed belt according to embodiments 1 and 2.

Fig. 6 is a fourth explanatory view showing a method of manufacturing the v-ribbed belt according to embodiments 1 and 2.

Fig. 7 is a fifth explanatory view showing a method of manufacturing the v-ribbed belt according to embodiments 1 and 2.

Fig. 8 is a sixth explanatory view showing a method of manufacturing the v-ribbed belt according to embodiments 1 and 2.

Fig. 9 is a design diagram of a pulley of an operation testing machine for measuring the crack life.

FIG. 10 is a design view of a pulley of a high tension belt running test machine.

Fig. 11 is a diagram illustrating a friction coefficient measuring method.

Fig. 12 is a pulley layout diagram showing an automobile auxiliary machinery drive belt transmission device using the v-ribbed belt of the embodiment.

Fig. 13 is a perspective view schematically showing a flat belt according to an example of embodiment 3.

Fig. 14 is a first explanatory view showing a method of manufacturing a flat belt according to embodiment 3.

Fig. 15 is a second explanatory view showing a method of manufacturing a flat belt according to embodiment 3.

Fig. 16 is a third explanatory view showing a method of manufacturing a flat belt according to embodiment 3.

FIG. 17 is a diagram showing the structure of a friction coefficient measuring apparatus.

Fig. 18 is a pulley design diagram showing a belt running test machine for evaluating wear resistance.

Fig. 19 is a pulley design diagram showing a belt running test machine for evaluating bending fatigue resistance.

Fig. 20 is a pulley design diagram showing a belt running test machine for evaluating friction and wear characteristics.

Fig. 21 is a pulley design diagram showing a belt running test machine for evaluating wear resistance.

Fig. 22 is a perspective view schematically showing a toothed belt according to an example of embodiment 4.

Fig. 23 is a partial sectional view of a belt molding die for manufacturing the toothed belt of embodiment 4.

Fig. 24 is a first explanatory view of a method of manufacturing the toothed belt according to embodiment 4.

Fig. 25 is a second explanatory view of the method for manufacturing the toothed belt according to embodiment 4.

Fig. 26 is a third explanatory view of the method for manufacturing the toothed belt according to embodiment 4.

Fig. 27 is a first explanatory view of a method of manufacturing the toothed belt according to embodiment 5.

Fig. 28 is a second explanatory view of the method for manufacturing the toothed belt according to embodiment 5.

Fig. 29 is a third explanatory view of the method for manufacturing the toothed belt according to embodiment 5.

Fig. 30 is a cross-sectional view showing an interface structure between the tooth-side reinforcing cloth and the toothed belt body in embodiment 7.

Fig. 31 is a cross-sectional view showing an interface structure between a tooth-side reinforcing cloth and a toothed belt body in embodiment 8.

Fig. 32 is a pulley design diagram showing a belt running test machine for evaluating tooth chipping resistance and wear resistance of a toothed belt.

Description of the symbols

10V-ribbed belt body

11 compression rubber layer

12 adhesive rubber layer

13 backing rubber layer

16 short fiber

120 flat belt body

121 inner rubber layer

122 adhesive rubber layer

123 outer rubber layer

126 short fiber

310 tooth belt main body

311a base

311b tooth part

312 core wire

313 tooth side reinforcing cloth

314 RFL adhesion layer

315 rubber paste adhesive layer

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings.

[ embodiment 1]

(V-ribbed belt B)

Fig. 1 and 2 show a v-ribbed belt B according to embodiment 1. The v-ribbed belt B according to embodiment 1 is an endless power transmission member used for an accessory drive belt transmission device or the like provided in an engine room of an automobile, for example. The V-ribbed belt B according to embodiment 1 has, for example, a belt length of 700 to 3000mm, a belt width of 10 to 36mm, and a belt thickness of 4.0 to 5.0 mm.

The v-ribbed belt B according to embodiment 1 includes a rubber-made v-ribbed belt body 10, and the v-ribbed belt body 10 has a three-layer structure including: a compression rubber layer 11 constituting a pulley contact portion on the inner peripheral side of the belt, an intermediate adhesive rubber layer 12, and a back rubber layer 13 on the outer peripheral side of the belt. The core wire 14 is embedded in the thickness direction intermediate portion 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. Further, instead of the back rubber layer 13, a back reinforcement cloth may be provided, and the v-ribbed belt body 10 may be formed as a double layer of the compression rubber layer 11 and the adhesive rubber layer 12.

The compression rubber layer 11 is provided with a plurality of V-shaped ribs 16 hanging down along the inner peripheral side of the belt. The plurality of V-shaped ribs 16 are each formed as a projecting strip having a substantially inverted triangular cross section extending in the belt length direction, and are arranged in line in the belt width direction. Each V-shaped rib 16 has, for example, a rib height of 2.0 to 3.0mm and a width between the base ends of 1.0 to 3.6 mm. The number of the V-shaped ribs 16 is, for example, 3 to 6 (6 in FIG. 1). The adhesive rubber layer 12 is formed in a strip shape having a cross-sectional rectangular shape, and has a thickness of, for example, 1.0 to 2.5 mm. The back rubber layer 13 is also formed in a strip shape having a cross-sectional rectangular shape, and has a thickness of, for example, 0.4 to 0.8 mm. In order to suppress the generation of sound during the back driving, a woven fabric pattern is preferably provided on the surface of the back rubber layer 13.

The compression rubber layer 11, the adhesive rubber layer 12, and the backing rubber layer 13 are formed of a rubber composition prepared by mixing and kneading various rubber compounding agents in rubber components, heating and pressurizing the uncrosslinked rubber composition, and crosslinking the rubber composition with a crosslinking agent. The rubber compositions forming the compression rubber layer 11, the adhesive rubber layer 12, and the backing rubber layer 13 may be the same or different.

Examples of the rubber component of the rubber composition for forming the compression rubber layer 11, the adhesive rubber layer 12, and the back rubber layer 13 include ethylene- α -olefin elastomers such as ethylene-propylene copolymer (EPR), ethylene-propylene-diene terpolymer (EPDM), ethylene-octene copolymer, and ethylene-butene copolymer, Chloroprene Rubber (CR), chlorosulfonated polyethylene rubber (CSM), and hydrogenated acrylonitrile rubber (H-HBR). The rubber component is preferably one or a mixed rubber of two or more of them. The rubber composition used for forming the compression rubber layer 11, the adhesion rubber layer 12, and the backing rubber layer 13 is preferably the same in rubber component.

At least one of the rubber compositions forming the compression rubber layer 11, the adhesive rubber layer 12 and the backing rubber layer 13 contains cellulose-based ultrafine fibers having a fiber diameter distribution range of 50 to 500 nm. All of the rubber compositions used for forming the compression rubber layer 11, the adhesion rubber layer 12, and the backing rubber layer 13 preferably contain cellulose-based microfibers, but more preferably, at least the rubber composition used for forming the compression rubber layer 11 constituting the pulley contact portion contains cellulose-based microfibers.

Cellulose-based microfibers are fiber materials derived from cellulose microfibers that are composed of skeletal components of plant cell walls obtained by finely disassembling plant fibers. Examples of the raw material plant of cellulose-based microfiber include wood, bamboo, rice (straw), potato, sugarcane (bagasse), waterweed, and seaweed. Among them, wood is preferable. By making the porous rubber composition forming the surface rubber layer 11a contain such cellulose-based ultrafine fibers, a higher reinforcing effect is found.

The cellulose-based ultrafine fiber may be the cellulose ultrafine fiber itself, or may be a hydrophobized cellulose ultrafine fiber after a hydrophobization treatment. As the cellulose-based microfiber, a cellulose microfiber and a hydrophobized cellulose microfiber may be used in combination. From the viewpoint of dispersibility, the cellulose-based ultrafine fibers preferably include hydrophobized cellulose ultrafine fibers. Examples of the hydrophobized cellulose microfine fibers include cellulose microfine fibers obtained by replacing a part or all of the hydroxyl groups of cellulose with hydrophobic groups, and cellulose microfine fibers subjected to a hydrophobization surface treatment using a surface treatment agent.

Examples of hydrophobization for obtaining a cellulose microfine fiber in which a part or all of the hydroxyl groups of cellulose are replaced with hydrophobic groups include esterification (acylation) (alkyl esterification, complex esterification, β -keto acid esterification, etc.), alkylation, tosylation, epoxidation, arylation, and the like. Among them, esterification is preferable. Specifically, the esterified hydrophobized cellulose microfiber may be a cellulose microfiber obtained by acylating a part or all of the hydroxyl groups of cellulose with a carboxylic acid such as acetic acid, anhydrous acetic acid, propionic acid, or butyric acid, or a halide (particularly, a chloride) thereof. Examples of the surface treatment agent for obtaining the cellulose ultrafine fibers subjected to the hydrophobic surface treatment with the surface treatment agent include a silane coupling agent.

The lower limit of the distribution of the fiber diameter of the cellulose-based microfine fiber is preferably 10nm or less, more preferably 3nm or less, from the viewpoint of realizing the tape characteristics. The upper limit is preferably 500nm or more, more preferably 700nm or more, and still more preferably 1 μm or more. The cellulose-based ultrafine fibers preferably have a fiber diameter distribution range of 20 to 500nm, more preferably 20 to 700nm, and still more preferably 20nm to 1 μm.

The average fiber diameter of the cellulose-based microfiber is preferably 3nm or more and 200nm or less, and more preferably 3nm or more and 100nm or less.

After a sample of the rubber composition constituting the tape body was frozen and pulverized, the cross section thereof was observed with a Transmission Electron Microscope (TEM), and the fiber diameter was measured by selecting 50 cellulose microfibers as desired, and the fiber diameter distribution of the cellulose microfibers was determined based on the measurement results. The average of the fiber diameters of the arbitrarily selected 50 cellulose microfibers was determined as the average fiber diameter of the cellulose microfibers.

The cellulose-based microfiber may be a cellulose-based microfiber with a high aspect ratio produced by a mechanical defibration method, or may be a cellulose-based microfiber produced by a chemical defibration method. Among them, the production by a chemical defibration method is preferable. As the cellulose-based microfiber, cellulose-based microfibers produced by a mechanical defibration method and a chemical defibration method may be used in combination. Examples of the defibrating apparatus used in the mechanical defibrating method include a kneader such as a twin-screw kneader, a high-pressure homogenizer, a mill, and a sand mill. Examples of the treatment for the chemical defibration method include acid hydrolysis treatment.

The content of the cellulose-based ultrafine fibers in the rubber composition constituting the compression rubber layer 11, the adhesive rubber layer 12 and/or the backing rubber layer 13 is preferably 1 part by mass or more, more preferably 5 parts by mass or more, further preferably 10 parts by mass or more, and further preferably 30 parts by mass or less, more preferably 25 parts by mass or less, further preferably 20 parts by mass or less, per 100 parts by mass of the rubber component, from the viewpoint of satisfying various characteristics of the transmission belt.

Examples of the rubber compounding agent include a reinforcing material, oil, a processing aid, a vulcanization accelerator aid, a crosslinking agent, an auxiliary crosslinking agent, and a vulcanization accelerator.

Examples of the short fibers used as the reinforcing material other than the cellulose microfiber include 6-nylon fiber, 6-nylon fiber, 4, 6-nylon fiber, polyester fiber (PET), polyethylene naphthalate (PEN) fiber, para-aramid fiber, meta-aramid fiber, and polyester fiber, and only one kind or a plurality of kinds may be contained. For example, a long fiber subjected to an adhesion treatment such as dipping in an RFL aqueous solution and heating may be cut into a predetermined length to produce a short fiber.

The diameter of the short fibers is preferably 1 μm or more, more preferably 5 μm or more, further preferably 10 μm or more, and further preferably 100 μm or less, more preferably 70 μm or less, further preferably 50 μm or less.

The amount of the short fibers is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and preferably 50 parts by mass or less, more preferably 40 parts by mass or less, per 100 parts by mass of the rubber component of the rubber composition.

Examples of the carbon black include furnace black such as channel black, SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF and N-234, thermal black such as FT and MT, and acetylene black.

In the case of using cellulose-based microfine fibers, carbon black is not necessarily added, but carbon black may be added for antistatic purposes and the like. When carbon black is added, the amount of carbon black blended is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and further preferably 100 parts by mass or less, more preferably 50 parts by mass or less, per 100 parts by mass of the rubber component of the rubber composition.

Examples of the oil include mineral oils such as petroleum softeners and paraffin oils, and vegetable oils such as castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, peanut oil, paraffin, rosin oil, and pine oil. The oil is preferably one kind or two or more kinds thereof. The oil content may be, for example, 5 to 15 parts by mass per 100 parts by mass of the rubber component of the rubber composition.

Examples of the vulcanization-accelerating assistant include metal oxides such as zinc oxide (zinc white) and magnesium oxide, metal carbonates, fatty acids, and derivatives thereof. The vulcanization-accelerating assistant is preferably one or two or more thereof. The content of the vulcanization-accelerating assistant may be, for example, 5 to 15 parts by mass per 100 parts by mass of the rubber component of the rubber composition.

Examples of the crosslinking agent include sulfur and an organic peroxide. The crosslinking agent may contain sulfur, an organic peroxide, or both. The amount of the crosslinking agent to be blended may be, for example, 0.5 to 4.0 parts by mass per 100 parts by mass of the rubber component of the rubber composition in the case of sulfur, and 0.5 to 8.0 parts by mass per 100 parts by mass of the rubber component of the rubber composition in the case of an organic peroxide.

Examples of the organic peroxide include dialkyl peroxides such as dicumyl peroxide, peroxyesters such as t-butyl peroxyacetate, and ketone peroxides such as dicyclohexylketone peroxide. One or more organic peroxides may be used.

Examples of the co-crosslinking agent include maleimides, TAIC, 1, 2-polybutadiene, oximes, guanidine, trimethylolpropane trimethacrylate, and the like. The auxiliary crosslinking agent is preferably one or two or more thereof. The content of the co-crosslinking agent may be, for example, 0.5 to 15 parts by mass per 100 parts by mass of the rubber component.

The adhesive rubber layer 12 and the back rubber layer 13 are formed of a solid rubber composition prepared by mixing and kneading various rubber compounding agents in rubber components, heating and pressurizing the resulting uncrosslinked rubber composition, and crosslinking the rubber composition with a crosslinking agent. The rubber component of the rubber composition constituting the adhesive rubber layer 12 and the backing rubber layer 13 may be the same as or similar to that of the compression rubber layer 11. As the rubber compounding agent, a reinforcing material, oil, a processing aid, a vulcanization accelerating aid, a crosslinking agent, an auxiliary crosslinking agent, a vulcanization accelerator, and the like can be cited as in the case of the compression rubber layer 11. The rubber composition for forming the adhesive rubber layer 12 and the backing rubber layer 13 may contain cellulose-based microfine fibers and short fibers, as in the case of the compression rubber layer 11.

The core 14 is formed of a strand such as a twisted yarn or a braided rope of polyethylene terephthalate (PET) fiber, polyethylene naphthalate (PEN) fiber, para-aramid fiber, vinylon fiber, or the like. In order to achieve adhesion to the ribbed belt body 10, the core wire 14 is subjected to adhesion treatment by dipping in an RFL aqueous solution and heating before molding and/or adhesion treatment by dipping in a rubber paste and drying. Before the adhesive treatment with the RFL aqueous solution and/or the rubber paste, the core wire 14 may be subjected to an adhesive treatment of dipping in an adhesive solution made of a solution such as an epoxy resin or a polyisocyanate resin and heating, if necessary. The diameter of the core wire 14 may be, for example, 0.5 to 2.5mm, and the dimension between the centers of the core wires 14 adjacent to each other in the cross section may be, for example, 0.05 to 0.20 mm.

(method of manufacturing V-ribbed belt B)

A method for manufacturing the v-ribbed belt B according to embodiment 1 will be described with reference to fig. 3 to 8.

Fig. 3 and 4 show a belt molding die 30 for manufacturing the v-ribbed belt B according to embodiment 1.

The belt molding die 30 includes an inner die 31 and an outer die 32, which are concentrically arranged and each have a cylindrical shape.

The inner mold 31 is formed of a flexible material such as rubber. The outer mold 32 is formed of a rigid material such as metal. The inner peripheral surface of the outer die 32 is formed as a molding surface, and V-rib forming grooves 33 having the same shape as the V-ribs 16 are provided at a constant pitch in the axial direction on the inner peripheral surface of the outer die 32. The outer mold 32 is provided with a temperature adjusting mechanism for adjusting the temperature by circulating a heat medium such as steam or a cooling medium such as water. In addition, a pressurizing member for pressurizing and expanding the inner mold 31 from the inside is provided.

The method for manufacturing the v-ribbed belt B according to embodiment 1 includes a material preparation step, a molding step, a crosslinking step, and a final processing step.

< Material preparation Process >

Uncrosslinked rubber sheets 11 ', 12 ', 13 ' for the compression rubber layer, the adhesion rubber layer and the backing rubber layer

The uncrosslinked rubber sheets 11 ', 12 ', and 13 ' for the compression rubber layer, the adhesive rubber layer, and the backing rubber layer were subjected to a manufacturing process containing cellulose-based ultrafine fibers in the following manner.

First, a cellulose-based microfiber is added to a masticated rubber component and kneaded to disperse the cellulose-based microfiber.

Among them, examples of the method for dispersing the cellulose-based microfine fibers as the rubber component include the following methods: a dispersion (gel) in which a cellulose-based ultrafine fiber is dispersed in water is put into a rubber component plasticated by an open mill, and water is vaporized while kneading the components; a cellulose-based microfiber/rubber master batch obtained by mixing a dispersion (gel) in which cellulose-based microfiber is dispersed in water with a rubber latex and vaporizing water is put into a masticated rubber component; a step of adding a cellulose-based microfiber/rubber master batch obtained by mixing a dispersion in which cellulose-based microfiber is dispersed in a solvent with a solution in which a rubber component is dissolved in a solvent and vaporizing the solvent to the masticated rubber component; a step of adding a pulverized product obtained by freeze-drying a dispersion (gel) in which a cellulose-based ultrafine fiber is dispersed in water to a masticated rubber component; and adding the hydrophobized cellulose-based ultrafine fiber to a masticated rubber component.

Then, various rubber compounding agents were added while the rubber component and the cellulose-based microfiber were kneaded, and the kneading was continued to prepare an uncrosslinked rubber composition.

Then, the uncrosslinked rubber composition is molded into a sheet shape by calendering or the like.

Further, a material containing no cellulose-based ultrafine fibers can be produced by mixing various rubber compounding agents into the rubber component, kneading the mixture with a kneading machine such as a kneader or a banbury mixer, and molding the resulting uncrosslinked rubber composition into a sheet form by calendering or the like.

-core wire 14-

The core wire 14' is subjected to an adhesion treatment. Specifically, the core wire 13' is subjected to RFL adhesion treatment in which it is immersed in an RFL aqueous solution and heated. Further, it is preferable to perform a base adhesion treatment by dipping in a base adhesion treatment liquid and heating before the RFL adhesion treatment. Further, a rubber paste adhesion treatment of dipping in a rubber paste and drying may be performed before the RFL adhesion treatment.

< Molding Process >

As shown in fig. 5, a rubber sleeve 35 is covered on a cylinder 34 having a smooth surface, and an uncrosslinked rubber sheet 13 ' for a back rubber layer and an uncrosslinked rubber sheet 12 ' for an adhesion rubber layer are sequentially laminated and wound on the outer periphery thereof, and a core wire 14 ' is spirally wound thereon with respect to a cylindrical inner mold 31, and then an uncrosslinked rubber sheet 12 ' for an adhesion rubber layer and an uncrosslinked rubber sheet 11 ' for a compression rubber layer are sequentially wound thereon. At this time, the laminated molded body B' is formed on the rubber sleeve 35.

< crosslinking step >

The rubber sleeve 35 provided with the laminated molded body B' is detached from the cylinder 34, and after being set in a state of being fitted inside the outer mold 32 on the inner peripheral surface side as shown in fig. 6, the inner mold 31 is positioned inside the rubber sleeve 35 provided with the outer mold 32 and sealed as shown in fig. 7.

Then, the outer mold 32 is heated, and high-pressure air or the like is injected into the sealed interior of the inner mold 31 to pressurize. At this time, the inner mold 31 is expanded to compress the uncrosslinked rubber pieces 11 ', 12 ', 13 ' of the laminated molded body B ' into the molding surface of the outer mold 32, and the core wires 14 ' are compositely integrated while crosslinking them, and finally, as shown in fig. 8, a cylindrical band plate S is molded. The molding temperature of the strip S may be, for example, 100 to 180 ℃, the molding pressure may be, for example, 0.5 to 2.0MPa, and the molding time may be, for example, 10 to 60 minutes.

< Final working procedure >

The inner mold 31 is depressurized to release the sealing, the band plate S formed between the inner mold 31 and the outer mold 32 by the rubber sleeve 35 is taken out, the band plate S is cut into a wheel shape with a predetermined width, and the inside and the outside are turned over, thereby manufacturing the v-ribbed belt B.

Examples-

[ test evaluation 1]

The edge-cut V-belts of examples 1-1 to 1-5 and comparative examples 1-1 to 1-8 were produced using a rubber composition containing chloroprene rubber (also referred to as CR rubber) as a rubber component. The details of each are also shown in table 1.

< example 1-1 >)

A master batch of cellulose microfiber/CR was prepared by mixing CR latex (trade name: Chloroprene842A, manufactured by Showa Denko K.K.) with an aqueous dispersion of cellulose microfiber (manufactured by Dawang paper Co., Ltd.) produced by a mechanical defibration method, and vaporizing water.

Then, CR (trade name: ChloropreneGS, manufactured by Showa Denko K.K.) was masticated, and a master batch was put therein and kneaded. The amount of the added master batch was 20 parts by mass based on the total amount of CR as 100 parts by mass.

Then, CR and cellulose-based microfiber were kneaded, 20 parts by mass of carbon black HAF (product name of Toshiba carbon Co., Ltd.: SEAST3), 5 parts by mass of aromatic polyamide short fiber (Technira (registered trademark)), 5 parts by mass of oil (product name of SUN Petroleum Co., Japan: SUNPAR2280), 5 parts by mass of zinc oxide (product name of chemical industry Co., Ltd.), and 4 parts by mass of magnesium oxide (product name of Kyowamag150, Co., Ltd.) were added to 100 parts by mass of CR, and the kneading was continued to prepare an uncrosslinked rubber composition.

The uncrosslinked rubber composition was molded into a sheet shape, and a cut-edge V-shaped belt of example 1-1 was produced as an uncrosslinked rubber sheet for constituting a belt body (compression rubber layer, adhesive rubber layer, and tension rubber layer).

In addition, a twisted yarn of polyester fiber subjected to an adhesion treatment was used as the core yarn.

< example 1-2 >

An uncrosslinked rubber composition was prepared by kneading and pressurizing CR with 10 parts by mass of cellulose microfibers produced by a chemical defibration method (TEMPO oxidation treatment), 20 parts by mass of carbon black HAF as a reinforcing material, 5 parts by mass of oil, 5 parts by mass of zinc oxide as a vulcanization-accelerating aid, and 4 parts by mass of magnesium oxide, relative to 100 parts by mass of CR.

A trimmed V-belt of example 1-2 having the same structure as in example 1-1 was produced as an uncrosslinked rubber sheet for constituting a belt main body, except that the uncrosslinked rubber composition was used.

< example 1-3 >

As the uncrosslinked rubber sheet used for forming the belt main body, a belt of example 1-3 was produced which had the same structure as that of example 1-2, except that carbon black was not blended and the content of the cellulose-based microfiber which was chemically defibrated was set to 20 parts by mass with respect to 100 parts by mass of the rubber component.

< example 1-4 >

As the uncrosslinked rubber sheet constituting the belt main body, belts of examples 1 to 4 having the same configuration as in example 1 to 2 were produced, except that 10 parts by mass of the aramid short fiber was added to 100 parts by mass of the rubber component and 10 parts by mass of the nylon short fiber (short fiber having a length of 3mm cut from a tire cord made of nylon 66 manufactured by TORAY) was further added.

< example 1-5 >

Tapes of examples 1 to 5 having the same constructions as in examples 1 to 2 were produced, except that 20 parts by mass of nylon short fibers were blended instead of 20 parts by mass of the aramid short fibers as the uncrosslinked rubber sheets constituting the tape main body.

< comparative example 1-1 >)

The belt of comparative example 1-1 having the same structure as that of example 1-1 was produced, except that the cellulose-based microfiber was not blended as the uncrosslinked rubber sheet constituting the belt main body.

< comparative example 1-2 >

A belt of comparative example 1-2 was produced in the same configuration as in comparative example 1-1, except that the amount of carbon black HAF blended was set to 70 parts by mass per 100 parts by mass of the rubber component as an uncrosslinked rubber sheet constituting the belt body.

< comparative examples 1 to 3 >

The belts of comparative examples 1 to 3 having the same structures as those of comparative example 1 to 1 were produced, except that 20 parts by mass of nylon short fibers were blended instead of 20 parts by mass of the aromatic polyamide short fibers as the uncrosslinked rubber sheets constituting the belt main body.

< comparative examples 1 to 4 >

As the uncrosslinked rubber sheet constituting the belt main body, belts of comparative examples 1 to 4 having the same structure as that of comparative examples 1 to 2 were produced, except that the compounding amount of carbon black HAF was set to 70 parts by mass with respect to 100 parts by mass of the rubber component and 20 parts by mass of nylon short fiber was compounded instead of 20 parts by mass of the aromatic polyamide short fiber.

< comparative example 1-5 >

The belt of comparative examples 1 to 5 having the same structure as that of comparative example 1 to 1 was produced, except that 20 parts by mass of a cellulose fiber (kraft pulp manufactured by Dawang paper company) other than a non-microfine fiber (fiber diameter about 10 to 100 μm) was blended per 100 parts by mass of the rubber component as an uncrosslinked rubber sheet constituting the belt main body.

< comparative examples 1 to 6 >

As the uncrosslinked rubber sheet constituting the belt main body, belts of comparative examples 1 to 6 having the same configuration as that of comparative examples 1 to 5 were produced except that carbon black HAF was not blended and 20 parts by mass of non-microfine fiber was blended with respect to 100 parts by mass of the rubber component.

< comparative examples 1 to 7 >

Belts of comparative examples 1 to 7 having the same structure as in example 1 to 2 were produced, except that the aromatic polyamide short fibers were not blended as the uncrosslinked rubber sheets constituting the belt main body.

< comparative examples 1 to 8 >

Belts of comparative examples 1 to 8 having the same structures as in examples 1 to 2 were produced, except that carbon black HAF and an aromatic polyamide short fiber were not blended as an uncrosslinked rubber sheet constituting a belt main body.

[ Table 1]

Band breakage in a short time (around 30 minutes) and no measure

(test evaluation method)

The results of the various evaluations are shown in table 1.

< average fiber diameter, fiber diameter distribution >

After freezing and pulverizing the samples of the inner rubber layers with tapes of examples 1-1 to 1-5, the cross sections thereof were observed with a Transmission Electron Microscope (TEM), and the fiber diameters were measured by selecting 50 cellulose microfibers as desired, and the average of the fiber diameters was determined. In addition, the maximum value and the minimum value of the fiber diameter among 50 cellulose microfibers were obtained.

< crack resistance evaluation Belt run test >

The crack life of the belt is an index indicating the crack resistance of the rubber, and is more excellent as the life is longer.

Fig. 9 shows an operation tester 40 for measuring the crack life. A belt running tester 40 for evaluating crack resistance is provided with a pulley diameter

A drive pulley 41 of 40mm and a driven pulley 42 of 40mm diameter provided on the right side thereof. The driven pulley 42 is provided to be movable left and right so as to be able to receive an axial load (self weight DW) and apply tension to the V-belt B.

The belts of examples 1-1 to 1-5 and comparative examples 1-1 to 1-8 were wound between the drive pulley 41 and the driven pulley 42 of the operation tester 40, and the driven pulley 42 was subjected to an axial load of 600N to the right side to apply tension to the belts, and the drive pulley 41 was rotated at 3000rpm at an ambient temperature of 100 ℃. Then, the running belt was stopped periodically, and whether or not a crack was generated in the cut V-belt B was visually checked, and the running time of the belt until the generation of the crack was checked was regarded as the crack resistance life. In addition, when the occurrence of cracks was not confirmed even after more than 200 hours, the test was ended at that time.

< high tension Belt running test >

The high tension durability evaluation under the self-weight condition is effective as an accelerated evaluation of the performance and life of the belt. If the belt length change based on the permanent tension of the core wire is considered to be constant, the greater the permanent deformation and wear of the rubber member, the greater the change in the inter-axial distance before and after the operation. Thus, the smaller the change in the inter-axial distance between before and after the operation, the better. The change in the mass of the belt before and after operation is an index indicating the abrasion resistance of the rubber member, and the smaller the change, the better the change.

Fig. 10 shows a high tension belt running test machine 50.

The two-axis high tension belt running test machine 50 has a pulley diameter

A driving V-pulley 51 of 100mm and a driven V-pulley 52 of 60mm diameter provided on the right side thereof. The driven V-pulley 52 is provided to be movable left and right so as to be able to bear an axial load (self weight DW) and apply tension to the belt.

The mass of each of the belts B of examples 1-1 to 1-6 and comparative examples 1-1 to 1-4 before running was measured as an initial mass.

Then, the belt was mounted on a high tension belt running tester 50, and the following load between shafts was applied to the driven pulley. That is, 1000N was applied to the case where the aramid short fiber was blended alone (examples 1-1 to 1-3, comparative examples 1-1 and 1-2), 800N was applied to the case where both the aramid short fiber and the nylon short fiber were blended (examples 1-4, comparative examples 1-5 and 1-6), 500N was applied to the case where the nylon short fiber was blended alone (examples 1-5, comparative examples 1-3 and 1-4), and 500N was applied to the case where the short fiber was not blended (comparative examples 1-7 and 1-8).

First, the ambient temperature was set to 100 ℃, and the driving pulley was operated at 5000rpm for 10 minutes as a no-load state, and then the shaft pitch was measured as an initial shaft pitch.

Then, the driving V pulley 51 was rotated at 5000rpm in a state where the following load was applied to the driven V pulley 52. That is, 40Nm was applied to the examples (examples 1-1 to 1-3, comparative examples 1-1 and 1-2) in which the aramid short fibers were blended alone, and 30Nm was applied to the examples (examples 1-4, comparative examples 1-5 and 1-6) in which both the aramid short fibers and the nylon short fibers were blended. 20Nm was applied to examples (examples 1 to 5, comparative examples 1 to 3 and 1 to 4) in which nylon staple fibers were blended alone, and 20Nm was applied to examples (comparative examples 1 to 7 and 1 to 8) in which staple fibers were not blended.

After 200 hours of operation, the interaxial distance was measured as the interaxial distance after operation when no load was applied for 10 minutes.

The change (%) in the interaxial distance after the operation was calculated in the following manner.

Interaxial distance variation (%)

(post-operation axial distance-pre-operation axial distance)/pre-operation axial distance x 100

The belt weight after the operation was measured and used as the belt weight after the operation. The weight change of the belt was calculated in the following manner.

With weight change (%)

(belt weight before operation-belt weight after operation)/belt weight before operation x 100

Of these, comparative examples 1 to 7 and 1 to 8 were broken in a short time (about 30 minutes) after the start of the operation, and the measurement related to the high-tension operation test could not be performed.

< coefficient of friction >

Fig. 11 shows a friction coefficient measuring device.

The friction coefficient measuring device 40 is constituted by a test pulley 82 and a load cell 83 provided on one side thereof, and the test pulley 82 is constituted by a rib pulley having a pulley diameter of 75 mm. The test pulley 82 is made of a ferrous material S45C. The test piece 81 of the trimmed V-belt extends horizontally from the load cell 83 and is wound around the test pulley 82, i.e., is disposed at a winding angle of 90 ° with respect to the test pulley 82.

Each of the non-operated V-belts of examples 1-1 to 1-6 and comparative examples 1-1 to 1-4 was cut to prepare a test piece 81 of a V-belt, one end of which was fixed to a load cell 83 and then wound around a test pulley 82, and a weight 84 was suspended and attached to the other end. Then, the test pulley 82 was rotated at a rotation speed of 43rpm in a direction to lower the weight 84 at an ambient temperature of 25 ℃, and the tension Tt received by the horizontal portion between the test pulley 82 and the load cell 83 of the test piece 81 was detected by the load cell 83 at 60 seconds after the start of the rotation. The tensile force Ts applied to the vertical portion of the weight 84 and the test pulley 82 of the test piece 81 is the weight 17.15N of the weight 84. Then, based on the formula of Euler, the friction coefficient μ when the surface of the compressed rubber layer is dried is obtained by the following formula (1). In addition, θ is π/2.

The same test was carried out on the trimmed V-belts after the high tension belt running test to determine the friction coefficient when the surface of the inner rubber layer was dried. Then, the ratio of the friction coefficient at the time of drying without operation to the friction coefficient at the time of drying after operation (friction coefficient (after operation)/friction coefficient (not in operation)) was determined. The ratio of the friction coefficients before and after the operation is an index of change in the friction coefficient, and the closer the ratio is to 1, the more stable the power transmission is, which is preferable.

[ equation 1]

< adhesive wearability >

After the high tension belt running test, the belt was detached from the high tension belt running test machine 50, and it was visually confirmed whether or not rubber adhesion abrasion occurred at the contact portion with the pulley and the pulley surface.

The presence or absence of adhesive wear after the high tension running test is an index showing the adhesive wear resistance of the rubber. The occurrence of the adhesive wear is a cause of abnormal noise and vibration of the belt, fixation to the pulley, and the like, and it is preferable that no adhesive wear occurs.

< Strength holding ratio >

After the high tension belt running test, a tensile test of the belt was performed, and the breaking strength of the belt was divided by the number of embedded core wires at the breaking portion, to measure the strength after running of one core wire.

In addition, the strength of one core wire before the operation of the same lot of the belt was measured in the same manner, and the strength retention ratio of the belt was determined in the following manner. The results are shown in Table 1.

Strength retention (%) of tape

Strength of one core wire after operation/strength of one core wire before operation x 100

The strength retention of the tape after the high tension running test is an index indicating the magnitude of damage to the tensile member (core wire) in the test. In the case of the V-belt, the local deformation of the core wire becomes large due to the bending caused by the permanent deformation of the bottom rubber, and the winding diameter with respect to the pulley becomes small due to the abrasion of the rubber, so that the deformation of the core wire becomes large and the damage occurs. Further, if the friction coefficient of the rubber becomes large and the separation from the pulley is poor when the belt is separated from the pulley, a stimulus of reverse bending is caused to promote fatigue of the core wire. This is a combined action, and therefore, it can be judged that the higher the strength retention of the tape, the higher the performance of the rubber covering the core wire.

(test evaluation results)

The results of the experiment are shown in table 1.

As is apparent from Table 1, the cellulose ultrafine fibers of examples 1-1 to 1-5 had a wide distribution of fiber diameters.

In examples 1-1 to 1-5 in which cellulose-based ultrafine fibers and other short fibers were used together, the belt crack resistance life was 200 hours or more. In addition, after the high tension running test, the change of the shaft distance is 1-2%, the change of the belt weight is 2-3%, the adhesive abrasion does not occur, and the strength retention rate of the belt is 88-90%. The friction coefficient ratio before and after the high tension running test was 0.95. In each example, the types of cellulose-based ultrafine fibers (mechanical defibration and chemical defibration) and the types of short fibers (aromatic polyamide short fibers and nylon short fibers) were different, but good results were obtained. In examples 1 to 3, the amount of the cellulose-based microfiber was increased without adding carbon black as compared with other examples (1 to 2, 1 to 4, and 1 to 5) using the same kind of cellulose-based microfiber. That is, carbon black may be completely replaced with cellulose-based microfiber. In this case, as with the results of the other examples, a rubber composition not using carbon black can be provided.

On the other hand, comparative examples 1-1 to 1-4 were reinforced with aramid short fibers or nylon short fibers, but the belt was made of rubber not blended with cellulose-based microfiber.

In comparative examples 1-1 and 1-3 in which the amount of carbon black was 20 parts by mass, the belt crack life was 200 hours or more, the belt crack resistance was not sticky and was not worn, the friction coefficient ratio was 0.9, and the belt crack resistance was close to that of the examples. However, the change in the mass of the belt before and after the high-tension running test was 20%, and the abrasion resistance of the rubber was extremely poor. As a result, the change in the inter-axial distance was also large, 20%. The retention of strength after operation was as low as 31 or 33%. This is because too high a friction coefficient causes poor separation from the pulley and bending deformation of the rubber, which promotes fatigue of the core wire.

On the contrary, in comparative examples 1-2 and 1-4 in which the amount of carbon black added was 70 parts by mass, the abrasion resistance (belt mass change) of the rubber could be improved to 3%, but the belt crack life deteriorated to 10 or 20. The reason why the change in the distance between the shafts of the belt is large, 10%, is that the rubber itself generates heat during operation, and the permanent deformation of the rubber is large. Also, adhesive wear occurs, and the friction coefficient changes. The retention of the belt strength after running was also low, 42 or 48%. This is because the increase in the friction coefficient leads to a deterioration in separability from the pulley and self-heating of the rubber promotes fatigue of the core wire.

In the following, comparative examples 1 to 5 and 1 to 6 are examples in which kraft pulp was used as the cellulose having a larger size in place of the cellulose-based microfiber. Comparative examples 1 to 5 are different from comparative examples 1 to 6 in the presence or absence of carbon black. The crack life and wear resistance of both examples deteriorate. In addition, the tape strength retention rate is also low, and the fatigue of the core wire is promoted. The reason for this is the same as in comparative examples 1-1 and 1-3.

Comparative examples 1 to 7 and 1 to 8 are examples in which cellulose-based microfine fibers were blended without reinforcing with short fibers. Comparative examples 1 to 7 are different from comparative examples 1 to 8 in the presence or absence of carbon black. The belt crack life of both of these examples was good, 200 hours or more, but the belt was broken in a short time in a high tension running test under high tension and high load bearing conditions, and the results of each purpose could not be measured. The reason for this is that the elastic modulus of the bottom rubber is insufficient, and the rubber is deformed by bending.

As described above, in comparative examples 1-1 to 1-8, the reinforcing method using carbon black and short fibers (nylon short fibers and aramid short fibers) together, the reinforcing method using cellulose fibers other than microfibers (including both cases of whether or not carbon black is blended), and the reinforcing method using cellulose microfibers without using other short fibers (including both cases of whether or not carbon black is blended) cannot satisfy all the desired performances at the same time. In particular, the performance was not satisfied under such a high temperature environment (100 ℃ C.) as the test conditions in the present example, and the use conditions were limited to low temperatures.

In contrast, by replacing a part or all of the carbon black with cellulose-based microfiber and working together with a short fiber-based reinforcement system, all of the desired properties can be satisfied at the same time. However, this needs to be achieved under such high temperature conditions of the present embodiment.

The specific mechanism remains to be understood, but it is considered that reinforcement based on cellulose-based microfibers differs from reinforcement based on carbon black in the manner of reinforcement. That is, the rubber layer (bound rubber) adsorbed by the carbon black suppresses the mobility of the rubber, thereby exhibiting carbon black reinforcement. Further, it is considered that chemical crosslinking does not occur in the rubber layer, and heat generation property becomes large when repeated deformation occurs, and adhesive wear occurs. In contrast, the details of reinforcing with cellulose-based ultrafine fibers are not clear, and therefore, this result is a fact that it is difficult to predict. However, as a result of the examination, the mobility of rubber molecules in the vicinity of the cellulose-based microfiber may not be suppressed as in the case of rubber molecules in the vicinity of carbon black, or the cellulose-based microfiber may be crosslinked to secure properties as a rubber-like elastic material. The reinforcing effect based on the cellulose-based ultrafine fibers may also be brought about by the three-dimensional network structure of the ultrafine fibers with each other. However, the effect and mechanism of using both cellulose-based microfiber and short fiber are not particularly relevant.

The evaluation contents of example 1-1 in which 20 parts by mass of the cellulose-based microfiber prepared by the mechanical defibration method was blended with 100 parts by mass of the rubber component were substantially the same as the evaluation contents of example 1-2 in which 10 parts by mass of the cellulose-based microfiber prepared by the chemical defibration method was similarly blended. Therefore, cellulose-based microfiber obtained by the chemical defibration method can achieve the same effect with a small amount of the cellulose-based microfiber.

[ test evaluation 2]

The belts of examples 2-1 to 2-5 and comparative examples 2-1 to 2-8 were produced using a rubber composition containing hydrogenated NBR (H-HBR) as a rubber component. The details of each are shown in table 2.

< example 2-1 >)

An H-HBR latex (product name: ZLX-B manufactured by ZEON Co., Japan) was mixed with an aqueous dispersion of cellulose microfiber produced by a mechanical defibration method, and water was vaporized to prepare a cellulose microfiber/H-HBR master batch.

Then, H-HBR (product name: Zetpol2020, ZEON Co., Japan) was masticated, and a master batch was put therein and kneaded. The amount of the masterbatch added was 20 parts by mass of the cellulose ultrafine fiber, when the total amount of H-HBR was 100 parts by mass.

Then, the H-HBR and the cellulose microfiber were kneaded, and 20 parts by mass of carbon black HAF as a reinforcing material, 20 parts by mass of an aromatic polyamide staple fiber, 10 parts by mass of an oil, 5 parts by mass of an organic peroxide (product name: PEROXYMON F40 manufactured by Nichikoku Co., Ltd.) as a crosslinking agent, and 1 part by mass of a co-crosslinking agent (product name: Hi-Cross M manufactured by Seiko chemical Co., Ltd.) were added to each of the above materials, and the above materials were kneaded to produce an uncrosslinked rubber composition.

The uncrosslinked rubber composition was molded into a sheet shape, and a cut-edge V-shaped belt of example 2-1 was produced as an uncrosslinked rubber sheet for constituting a belt body (compression rubber layer, adhesive rubber layer, and tension rubber layer).

In addition, as the core wire, a twisted yarn of polyester fiber subjected to an adhesion treatment was used.

< example 2-2 >

CR, 10 parts by mass of cellulose ultrafine fibers produced by a chemical defibration method (TEMPO oxidation treatment), 20 parts by mass of carbon black HAF as a reinforcing material, 10 parts by mass of oil, 5 parts by mass of an organic peroxide as a crosslinking agent, and 1 part by mass of a co-crosslinking agent were charged and kneaded, respectively, based on 100 parts by mass of the CR, to prepare an uncrosslinked rubber composition.

A trimmed V-belt of example 2-2 having the same structure as in example 2-1 was produced as an uncrosslinked rubber sheet for constituting a belt main body, except that the uncrosslinked rubber composition was used.

< example 2-3 >

A belt of example 2-3 having the same structure as that of example 2-2 was produced as the uncrosslinked rubber sheet constituting the belt main body, except that carbon black was not blended and the content of cellulose-based ultrafine fibers that were chemically defibrated was set to 20 parts by mass with respect to 100 parts by mass of the rubber component.

< example 2-4 >

A belt of example 2-4 having the same structure as that of example 2-2 was produced as an uncrosslinked rubber sheet constituting the belt main body, except that 10 parts by mass of the aramid short fiber was added to 100 parts by mass of the rubber component and 10 parts by mass of the nylon short fiber was further added.

< example 2-5 >

A belt of example 2-5 having the same structure as in example 2-2 was produced, except that 20 parts by mass of nylon short fibers were blended instead of 20 parts by mass of the aromatic polyamide short fibers as the uncrosslinked rubber sheets constituting the belt main body.

< comparative example 2-1 >

A belt of comparative example 2-1 having the same structure as that of example 2-1 was produced as an uncrosslinked rubber sheet constituting a belt main body, except that the amount of carbon black HAF was set to 30 parts by mass with respect to 100 parts by mass of the rubber component and that cellulose-based microfiber was not blended.

< comparative example 2-2 >

A belt of comparative example 2-2 was produced in the same configuration as comparative example 2-1, except that the amount of carbon black HAF added was 90 parts by mass per 100 parts by mass of the rubber component, as an uncrosslinked rubber sheet constituting the belt body.

< comparative example 2-3 >

A belt of comparative example 2-3 was produced in the same configuration as in comparative example 2-1, except that 20 parts by mass of nylon short fiber was blended instead of 20 parts by mass of aramid short fiber as an uncrosslinked rubber sheet constituting the belt main body.

< comparative example 2-4 >

A belt of comparative example 2-4 having the same structure as comparative example 2-1 was produced, except that the amount of carbon black HAF added was 90 parts by mass with respect to 100 parts by mass of the rubber component and 20 parts by mass of nylon short fiber was added instead of 20 parts by mass of the aromatic polyamide short fiber.

< comparative example 2-5 >

As the uncrosslinked rubber sheet constituting the belt main body, a belt of comparative example 2 to 5 having the same structure as that of comparative example 2 to 1 was produced, except that the amount of carbon black HAF added was set to 20 parts by mass with respect to 100 parts by mass of the rubber component and 20 parts by mass of the cellulose fiber other than the ultrafine fiber was added with respect to 100 parts by mass of the rubber component.

< comparative example 2-6 >

A belt of comparative example 2-5 was produced in the same manner as in comparative example 2-1, except that the non-crosslinked rubber sheet constituting the belt body was made of cellulose fibers other than the non-microfine fibers in an amount of 20 parts by mass based on 100 parts by mass of the rubber component, instead of carbon black HAF.

< comparative example 2-7 >

Belts of comparative examples 2 to 7 having the same structure as in example 2 to 2 were produced, except that the aromatic polyamide short fibers were not blended as the uncrosslinked rubber sheets constituting the belt main body.

< comparative example 2-8 >

Belts of comparative examples 2 to 8 having the same structure as in example 2 to 2 were produced, except that carbon black HAF and aramid short fibers were not blended as the uncrosslinked rubber sheet constituting the belt main body.

[ Table 2]

Band breakage in a short time (around 30 minutes) and no measure

(test evaluation method)

The average value, the minimum value and the maximum value of the fiber diameters of the cellulose ultrafine fibers of the tapes of examples 2-1 to 2-5 were determined in the same manner as in test evaluation 1. Further, the belt crack resistance life of each of the belts of examples 2-1 to 2-5 and comparative examples 2-1 to 2-8 was determined in the same manner as in test evaluation 1, and a high tension running test was performed to evaluate the change in the shaft pitch, the change in mass, the wear coefficient ratio, the presence or absence of adhesive wear after the test, and the strength retention rate.

However, the ambient temperature for measuring the belt crack life and the high tension running test was set to 120 ℃. Further, the belt crack life was measured up to 300 hours, and when no crack was observed even after exceeding 300 hours, the test was ended.

(test evaluation results)

The results of the experiment are shown in table 2.

As can be seen from Table 2, the same results as in test evaluation 1 were obtained even when the rubber component was set to H-HBR. In particular, even when the environmental temperature in the crack resistance evaluation belt running test and the high tension belt running test was higher (120 ℃) than in test evaluation 1, a good evaluation result was obtained. This is because, as one possibility, the reinforcing effect of the cellulose-based ultrafine fibers is less temperature-dependent than the reinforcing effect of the carbon black.

[ test evaluation 3]

The belts for test evaluation of examples 3-1 to 3-5 and comparative examples 3-1 to 3-8 were produced using a rubber composition containing EPDM as a rubber component. The details of each are shown in table 3.

< example 3-1 >)

A dispersion in which a cellulose microfiber produced by a mechanical defibration method was dispersed in toluene was mixed with a solution in which EPDM (product name of JSR company: EP33) was dissolved in toluene, and toluene was vaporized to prepare a cellulose microfiber/EPDM master batch.

Then, the EPDM was masticated, and the master batch was put therein and kneaded. The amount of the masterbatch added was 20 parts by mass of the cellulose ultrafine fiber, based on 100 parts by mass of the total amount of EPDM.

Then, EPDM and cellulose microfiber were kneaded, and 20 parts by mass of carbon black as a reinforcing material, 20 parts by mass of aramid short fiber, 10 parts by mass of oil, 5 parts by mass of organic peroxide as a crosslinking agent, and 1 part by mass of a co-crosslinking agent were added to 100 parts by mass of EPDM, respectively, and the kneaded mixture was continued to prepare an uncrosslinked rubber composition.

The uncrosslinked rubber composition was molded into a sheet shape, and a cut-edge V-shaped belt of example 3-1 was produced as an uncrosslinked rubber sheet for constituting a belt body (compression rubber layer, adhesive rubber layer, and tension rubber layer).

< example 3-2 >

An uncrosslinked rubber composition was prepared by kneading 10 parts by mass of a cellulose ultrafine fiber produced by a chemical defibration method (TEMPO oxidation treatment), 20 parts by mass of carbon black as a reinforcing material, 10 parts by mass of oil, 5 parts by mass of an organic peroxide as a crosslinking agent, and 1 part by mass of a co-crosslinking agent with 100 parts by mass of EPDM.

A trimmed V-belt of example 3-2 having the same structure as in example 3-1 was produced as an uncrosslinked rubber sheet for constituting a belt main body, except that the uncrosslinked rubber composition was used.

< example 3-3 >

A belt of example 3-3 having the same structure as that of example 3-2 was produced as the uncrosslinked rubber sheet constituting the belt main body, except that carbon black was not blended and the content of the cellulose-based microfiber subjected to fiber decomposition by a chemical method was set to 20 parts by mass with respect to 100 parts by mass of the rubber component.

< example 3-4 >

A belt of example 3-4 having the same structure as that of example 3-2 was produced as the uncrosslinked rubber sheet constituting the belt main body, except that 10 parts by mass of the aramid short fiber was added to 100 parts by mass of the rubber component and 10 parts by mass of the nylon short fiber was further added.

< example 3-5 >

A belt of example 3-5 having the same structure as in example 3-2 was produced, except that 20 parts by mass of nylon short fibers were blended instead of 20 parts by mass of the aromatic polyamide short fibers as the uncrosslinked rubber sheets constituting the belt main body.

< comparative example 3-1 >

A belt of comparative example 3-1 was produced in the same configuration as in example 3-1, except that the amount of carbon black HAF blended was 30 parts by mass per 100 parts by mass of the rubber component and that no cellulose-based microfiber was blended as an uncrosslinked rubber sheet constituting the belt body.

< comparative example 3-2 >

A belt of comparative example 3-2 was produced in the same manner as in comparative example 3-1, except that the amount of carbon black HAF blended was 90 parts by mass per 100 parts by mass of the rubber component, as an uncrosslinked rubber sheet constituting the belt body.

< comparative example 3-3 >

A belt of comparative example 3-3 was produced in the same manner as in comparative example 3-1, except that 20 parts by mass of nylon short fibers were blended instead of 20 parts by mass of the aramid short fibers as the uncrosslinked rubber sheets constituting the belt main body.

< comparative example 3-4 >

A belt of comparative example 3-4 having the same structure as comparative example 3-1 was produced, except that the amount of carbon black HAF added was 90 parts by mass per 100 parts by mass of the rubber component and 20 parts by mass of nylon short fiber was added instead of 20 parts by mass of the aromatic polyamide short fiber.

< comparative example 3-5 >

As the uncrosslinked rubber sheet constituting the belt main body, a belt of comparative example 3-5 having the same structure as comparative example 3-1 was produced, except that the amount of carbon black HAF was set to 20 parts by mass with respect to 100 parts by mass of the rubber component and 20 parts by mass of the non-microfine cellulose fiber was further blended with respect to 100 parts by mass of the rubber component.

< comparative example 3-6 >

A belt of comparative example 3-5 was produced in the same manner as in comparative example 3-1, except that carbon black HAF was not blended as an uncrosslinked rubber sheet constituting the belt main body, and that 20 parts by mass of non-microfine fibers was blended per 100 parts by mass of the rubber component.

< comparative example 3-7 >

A belt of comparative example 3-7 having the same structure as that of example 3-2 was produced, except that the non-crosslinked rubber sheet constituting the belt body was not blended with the aramid short fiber.

< comparative example 3-8 >

A belt of comparative example 3-8 having the same structure as that of example 3-2 was produced, except that carbon black HAF and an aromatic polyamide short fiber were not blended as an uncrosslinked rubber sheet constituting a belt main body.

[ Table 3]

Band breakage in a short time (around 30 minutes) and no measure

(test evaluation method)

The average value, the minimum value and the maximum value of the fiber diameters of the cellulose ultrafine fibers of the tapes of examples 3-1 to 3-5 were determined in the same manner as in test evaluation 1. Further, in the same manner as in test evaluation 1, the belt crack resistance life of each of the belts of examples 3-1 to 3-5 and comparative examples 3-1 to 3-8 was determined, and a high tension running test was performed to evaluate the change in the shaft pitch, the change in mass, the wear coefficient ratio, the presence or absence of adhesive wear after the test, and the strength retention rate.

(test evaluation results)

The results of the experiment are shown in table 3.

As can be seen from table 3, the same results as in test evaluations 1 and 2 were obtained even when the rubber component was EPDM. In particular, even when the environmental temperature in the crack resistance evaluation belt running test and the high tension belt running test was higher (120 ℃) than in test evaluation 1, a good evaluation result was obtained.

[ embodiment 2]

(V-ribbed belt B)

Fig. 1 and 2 are diagrams illustrating a v-ribbed belt B according to embodiment 2.

The v-ribbed belt B according to embodiment 2 may be, for example, an endless power transmission member for an accessory drive belt transmission device or the like provided in an engine room of an automobile. The V-ribbed belt B according to embodiment 2 has, for example, a belt length of 700 to 3000mm, a belt width of 10 to 36mm, and a belt thickness of 4.0 to 5.0 mm.

The v-ribbed belt B according to embodiment 2 includes a rubber-made v-ribbed belt body 10, and the v-ribbed belt body 10 has a three-layer structure including: a compression rubber layer 11 constituting a pulley contact portion on the inner peripheral side of the belt, an intermediate adhesive rubber layer 12, and a back rubber layer 13 on the outer peripheral side of the belt. The core wire 14 is embedded in the thickness direction intermediate portion 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. Further, a back reinforcement cloth may be provided instead of the back rubber layer 13, and the v-ribbed belt body 10 may be configured to have a double layer of the compression rubber layer 11 and the adhesive rubber layer 12.

The compression rubber layer 11, the adhesive rubber layer 12, and the backing rubber layer 13 are formed of a rubber composition prepared by mixing and kneading an uncrosslinked rubber composition containing rubber components with various rubber compounding agents under heating and pressure and crosslinking the rubber composition with a crosslinking agent. The rubber compositions used for forming the compression rubber layer 11, the adhesive rubber layer 12, and the backing rubber layer 13 may be the same or different.

At least one of the rubber compositions for forming the compression rubber layer 11, the adhesion rubber layer 12 and the backing rubber layer 13 contains cellulose-based ultrafine fibers having a fiber diameter distribution range of 50 to 500 nm. All of the rubber compositions used for forming the compression rubber layer 11, the adhesion rubber layer 12, and the backing rubber layer 13 preferably contain cellulose-based microfibers, but more preferably at least the rubber composition used for forming the compression rubber layer 11 constituting the pulley contact portion contains cellulose-based microfibers.

According to the v-ribbed belt B of embodiment 2, as described above, since at least one of the rubber compositions used for the compression rubber layer 11, the adhesive rubber layer 12, and the back rubber layer 13 constituting the v-ribbed belt body 10 contains the cellulose-based ultrafine fibers having the fiber diameter distribution range of 50 to 500nm, excellent bending fatigue resistance can be obtained. In particular, when the rubber composition forming the compression rubber layer 11 constituting the contact portion contains cellulose-based ultrafine fibers, high abrasion resistance and a stable friction coefficient can be obtained.

Cellulose-based microfibers are fiber materials derived from cellulose microfibers that are composed of skeletal components of plant cell walls obtained by finely disassembling plant fibers. Examples of the raw material plant of cellulose-based microfiber include wood, bamboo, rice (straw), potato, sugarcane (bagasse), waterweed, and seaweed. Among them, wood is preferable.

In the cellulose-based microfiber, it is preferable that the distribution of fiber diameters is wide and the distribution range of fiber diameters is 50 to 500nm in view of improving the bending fatigue resistance. From the above viewpoint, the lower limit of the distribution of the fiber diameter is preferably 20nm or less, and more preferably 10nm or less. From the same viewpoint, the upper limit is preferably 700nm or more, more preferably 1 μm or more. The distribution range of the fiber diameter of the cellulose-based microfiber preferably includes 20nm to 700nm, and more preferably 10nm to 1 μm.

The average fiber diameter of the cellulose-based microfine fibers contained in the rubber composition is preferably 10nm or more, more preferably 20nm or more, and further preferably 700nm or less, more preferably 100nm or less.

After a sample of the rubber composition was frozen and pulverized, the cross section was observed with a Transmission Electron Microscope (TEM), and the fiber diameter was measured by selecting 50 cellulose ultrafine fibers arbitrarily, and the fiber diameter distribution of the cellulose ultrafine fibers was determined based on the measurement result. The average of the fiber diameters of the arbitrarily selected 50 cellulose microfibers was determined as the average fiber diameter of the cellulose microfibers.

The cellulose-based ultrafine fiber may be a cellulose-based ultrafine fiber having a high aspect ratio produced by a mechanical defibration method, or may be a needle-like crystal produced by a chemical defibration method. Among them, the production is preferably carried out by a mechanical defibration method. As the cellulose-based microfiber, cellulose-based microfiber produced by a mechanical defibration method and cellulose-based microfiber produced by a chemical defibration method may be used in combination. Examples of the defibrating apparatus used in the mechanical defibrating method include a kneader such as a twin-screw kneader, a high-pressure homogenizer, a mill, and a sand mill. Examples of the treatment for the chemical defibration method include acid hydrolysis treatment.

The content of the cellulose-based microfine fiber in the rubber composition is preferably 1 part by mass or more, more preferably 3 parts by mass or more, further preferably 5 parts by mass or more, and further preferably 30 parts by mass or less, more preferably 20 parts by mass or less, further preferably 10 parts by mass or less, per 100 parts by mass of the rubber component, from the viewpoint of improving the bending fatigue resistance.

Examples of the rubber compounding agent include a reinforcing material, a processing oil, a processing aid, a vulcanization accelerator, a crosslinking agent, a vulcanization accelerator, and an antioxidant.

Examples of the carbon black include furnace black such as channel black, SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF and N-234, thermal black such as FT and MT, and acetylene black. Silicon dioxide can also be mentioned as a reinforcing material. The reinforcing material is preferably one or two or more thereof. The content of the reinforcing material is preferably 50 to 90 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of the oil include mineral oils such as petroleum softeners and paraffin oils, and vegetable oils such as castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, peanut oil, paraffin, rosin oil, and pine oil. The oil is preferably one kind or two or more kinds thereof. The oil content may be, for example, 10 to 30 parts by mass per 100 parts by mass of the rubber component of the rubber composition.

Examples of the processing aid include stearic acid, polyethylene wax, and metal salts of fatty acids. The processing aid is preferably one or two or more thereof. The content of the processing aid may be, for example, 0.5 to 2 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of the vulcanization-accelerating assistant include metal oxides such as zinc oxide (zinc white) and magnesium oxide, metal carbonates, fatty acids, and derivatives thereof. The vulcanization-accelerating assistant is preferably one or two or more thereof. The content of the vulcanization-accelerating assistant may be, for example, 3 to 7 parts by mass per 100 parts by mass of the rubber component of the rubber composition.

Examples of the antioxidant include benzimidazole-based antioxidants, aminoketone-based antioxidants, diamine-based antioxidants, phenol-based antioxidants, and the like. The aging inhibitor is preferably one or more of these. The content of the antioxidant may be, for example, 0.1 to 5 parts by mass per 100 parts by mass of the rubber component.

Examples of the co-crosslinking agent include maleimides, TAIC, 1, 2-polybutadiene, oximes, guanidines, trimethylolpropane trimethacrylates, and liquid rubbers. The auxiliary crosslinking agent is preferably one or two or more thereof. The content of the co-crosslinking agent may be, for example, 0.5 to 30 parts by mass per 100 parts by mass of the rubber component.

Examples of the crosslinking agent include sulfur and an organic peroxide. The crosslinking agent may contain sulfur, an organic peroxide, or both. The amount of the crosslinking agent to be blended may be, for example, 1 to 5 parts by mass per 100 parts by mass of the rubber component in the case of sulfur, or 1 to 5 parts by mass per 100 parts by mass of the rubber component in the case of organic peroxide.

Examples of the vulcanization accelerator include thiurams (e.g., TETD, TT, TRA, etc.), thiazoles (e.g., MBT, MBTs, etc.), sulfenamides (e.g., CZ, etc.), dithiocarbamates (e.g., BZ-P, etc.), and the like. The vulcanization accelerator is preferably one or two or more of them. The content of the vulcanization accelerator may be, for example, 1 to 3 parts by mass per 100 parts by mass of the rubber component of the rubber composition.

The rubber composition constituting the compression rubber layer 11, the adhesive rubber layer 12, and the backing rubber layer 13 may contain short fibers 16 having a fiber diameter of 10 μm or more. In particular, it is preferable that the rubber composition forming the compression rubber layer 11 constituting the pulley contact portion contains short fibers 16. In this case, the short fibers 16 are preferably contained in the compression rubber layer 11 so as to be oriented in the belt width direction, and a part of the short fibers 16 exposed on the surface of the V-shaped rib 15 of the compression rubber layer 11 preferably protrudes from the surface. In addition, the short fibers 16 may be grafted to the surface of the V-shaped ribs 15 of the compression rubber layer 11, instead of being blended with the rubber composition.

Examples of the short fibers 16 include nylon short fibers, vinylon short fibers, aramid short fibers, polyester short fibers, and cotton short fibers. For example, the short fibers 16 may be produced by cutting long fibers subjected to an adhesion treatment such as dipping in an RFL aqueous solution and heating to a predetermined length. The short fibers 16 may have a length of 0.2 to 5.0mm and a fiber diameter of 10 to 50 μm, for example.

The content of the short fibers 16 is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and further preferably 30 parts by mass or less, more preferably 20 parts by mass or less, per 100 parts by mass of the rubber component. The content of the short fibers 16 is preferably larger than that of the cellulose-based microfiber. The ratio of the content of the short fibers 16 to the content of the cellulose-based microfiber (the content of the short fibers 16 to the content of the cellulose-based microfiber) is preferably 1 or more, more preferably 2 or more, and further preferably 15 or less, and more preferably 5 or less. The total content of the cellulose-based microfine fibers and the short fibers 16 is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and further preferably 25 parts by mass or less, more preferably 15 parts by mass or less, per 100 parts by mass of the rubber component.

The core wire 14 is formed of a twisted yarn made of polyamide fiber, polyester fiber, aromatic polyamide fiber, or the like. The diameter of the core wire 14 may be, for example, 0.5 to 2.5mm, and the dimension between the centers of the core wires 14 adjacent to each other in the cross section may be, for example, 0.05 to 0.20 mm. The core wire 14 is subjected to an adhesion treatment having adhesion to the v-ribbed belt body 10.

Next, fig. 12 shows a pulley design of an auxiliary drive belt transmission 20 of an automobile using the v-ribbed belt B according to embodiment 2. The auxiliary drive belt transmission device 20 is a serpentine drive device that transmits power by winding a ribbed belt B around 6 pulleys of 4 ribbed wheels and 2 flat wheels.

In the auxiliary drive belt transmission device 20, a power steering pulley 21 as a ribbed wheel is provided at the uppermost position, and an AC generator pulley 22 as a ribbed wheel is provided below the power steering pulley 21. A tension pulley 23 as a flat wheel is provided on the lower left of the power steering pulley 21, and a water pump pulley 24 as a flat wheel is provided below the tension pulley 23. A crank pulley 25 as a ribbed wheel is provided on the lower left of the tightening pulley 23, and an air conditioning pulley 26 as a ribbed wheel is provided on the lower right of the crank pulley 25. These pulleys may be made of, for example, a metal press-formed part, a casting, or a resin molded product such as nylon resin or phenol resin, and have a pulley diameter

Can be 50-150 mm.

In the accessory drive belt transmission device 20, the v-ribbed belt B is provided with: the power steering pulley 21 is wound in contact with the V-rib 16 side, then wound in contact with the tension pulley 23 on the belt back side, then wound in contact with the V-rib 16 side in this order on the crankshaft pulley 25 and the air conditioning pulley 26, then wound in contact with the water pump pulley 24 on the belt back side, then wound in contact with the AC generator pulley 22 on the V-rib 16 side, and finally returned to the power steering pulley 21. The length of the V-ribbed belt B stretched between the pulleys, i.e., the belt span length, may be, for example, 50 to 300 mm. The axial difference that can occur between the pulleys may be 0 to 2 °.

(method of manufacturing V-ribbed belt B)

The method for manufacturing the v-ribbed belt B according to embodiment 2 is the same as that according to embodiment 1.

Examples-

[ poly V-belt ]

The V-ribbed belts of examples 4-1 to 4-9 and comparative example 4 were produced. Details are shown in table 4.

< example 4-1 >)

A dispersion in which powdery cellulose (product name of Japan paper-making company: KCFLOCK W-50GK) made of wood was dispersed in toluene was prepared, and the powdery cellulose was separated into cellulose microfibers by colliding the dispersions with each other using a high-pressure homogenizer to obtain a dispersion in which the cellulose microfibers were dispersed in toluene. Thus, the cellulose microfiber was produced by a mechanical defibration method and was not subjected to a hydrophobization treatment.

Then, the dispersion obtained by dispersing the cellulose microfiber in toluene was mixed with a solution obtained by dissolving ethylene propylene diene monomer (product name of JSR company, EP33, hereinafter referred to as "EPDM") in toluene, and toluene was vaporized to prepare a cellulose microfiber/EPDM master batch.

Then, the EPDM was masticated, and the master batch was put therein and kneaded. The amount of the masterbatch added was 1 part by mass of the cellulose ultrafine fiber, based on 100 parts by mass of the total amount of EPDM.

Then, EPDM and cellulose microfiber were kneaded, and 60 parts by mass of HAF carbon black (product name of Mitsubishi chemical company: DiabalackH), 15 parts by mass of processing oil (product name of SUN Petroleum company: SUNPAR2280), 1 part by mass of stearic acid (product name of New Nippon chemical company: stearic acid 50S) as a processing aid, 5 parts by mass of zinc oxide (product name of Nippon chemical company: three types of zinc oxide) as a vulcanization acceleration aid, 2.5 parts by mass of a antiaging agent for benzene (product name of New England chemical company: Nocrac MB), 2.3 parts by mass of sulfur (product name of thin well chemical company: oil sulfur) as a crosslinking agent, and 2 parts by mass of a vulcanization accelerator for thiuram (product name of New England chemical company: Nocseller TET-G) were introduced into each of 100 parts by mass of EPDM, the kneading was continued to prepare an uncrosslinked rubber composition.

Using this uncrosslinked rubber composition, a V-ribbed belt of example 4-1 having the same structure as that of embodiment 2 in which the compression rubber layer was formed in the belt width direction in the grain direction was produced.

For the V-ribbed belt of example 4-1, the belt length was 1400mm, the belt width was 2.2mm, the belt thickness was 4.5mm, and the number of V-ribs was 3. The adhesive rubber layer and the back rubber layer are formed of a rubber composition containing no cellulose ultrafine fiber and short fiber, and the core wire is formed of a twisted yarn of a polyester fiber subjected to an adhesive treatment.

< example 4-2 >

The V-ribbed belt of example 4-2 was produced in the same manner as in example 4-1, except that the content of the cellulose ultrafine fibers was set to 3 parts by mass with respect to 100 parts by mass of the rubber component.

< example 4-3 >

The V-ribbed belt of example 4-3 was produced in the same manner as in example 4-1, except that the content of the cellulose ultrafine fibers was set to 5 parts by mass with respect to 100 parts by mass of the rubber component.

< example 4-4 >

The V-ribbed belt of example 4-4 was produced in the same manner as in example 4-1, except that the content of the cellulose ultrafine fibers was 10 parts by mass with respect to 100 parts by mass of the rubber component.

< example 4-5 >

The V-ribbed belts of examples 4 to 5 were produced in the same manner as in example 4-1, except that the content of the cellulose ultrafine fibers was set to 15 parts by mass with respect to 100 parts by mass of the rubber component.

< example 4-6 >

The v-ribbed belts of examples 4 to 6 were produced in the same manner as in example 4-1, except that the content of the cellulose ultrafine fibers was set to 25 parts by mass with respect to 100 parts by mass of the rubber component.

< example 4-7 >

A V-ribbed belt of example 4-7 was produced in the same manner as in example 4-1, except that the uncrosslinked rubber composition used for the compression rubber layer contained 14 parts by mass of nylon short fibers (product name of Imperial corporation: CFN3000 fiber diameter: 26 μm fiber length: 3mm) per 100 parts by mass of the rubber component. The ratio of the content of short fibers to the content of cellulose-based microfiber ("B/A" in Table 4) was 14. The total content of the cellulose-based ultrafine fibers and short fibers ("a + B" in table 4) was 15 parts by mass with respect to 100 parts by mass of the rubber component.

< example 4-8 >

The v-ribbed belts of examples 4 to 8 were produced in the same manner as in example 4-2, except that 12 parts by mass of nylon short fibers per 100 parts by mass of the rubber component was contained in the uncrosslinked rubber composition used in the compression rubber layer. The ratio (B/A) of the content of the short fibers to the content of the cellulose-based microfiber was 4. The total content (a + B) of the cellulose-based ultrafine fibers and short fibers was 15 parts by mass with respect to 100 parts by mass of the rubber component.

< example 4-9 >

The v-ribbed belts of examples 4 to 9 were produced in the same manner as in example 4 to 3, except that 10 parts by mass of nylon short fibers per 100 parts by mass of the rubber component was contained in the uncrosslinked rubber composition used in the compression rubber layer. The ratio of the content of the short fibers to the content of the cellulose-based microfiber (the content of the short fibers relative to the content of the cellulose-based microfiber) was 3. The total content of the cellulose-based ultrafine fibers and short fibers was 15 parts by mass with respect to 100 parts by mass of the rubber component.

< comparative example 4 >

A v-ribbed belt of comparative example 4 was produced in the same manner as in example 4-1, except that the uncrosslinked rubber composition for the compression rubber layer did not contain the cellulose ultrafine fibers and 15 parts by mass of the nylon short fibers were contained with respect to 100 parts by mass of the rubber component.

[ Table 4]

(test evaluation method)

< average fiber diameter, fiber diameter distribution >

The collected samples of the rubber compositions constituting the compression rubber layer of the V-ribbed belts of examples 4-1 to 4-5 were frozen and crushed, and then the cross section thereof was observed by using a Scanning Electron Microscope (SEM), and the fiber diameters were measured by selecting 50 fibers arbitrarily, and the average thereof was determined as the average fiber diameter. In addition, the maximum value and the minimum value of the fiber diameter among 50 cellulose microfibers were obtained.

< Friction coefficient measurement test >

Fig. 17 shows a friction coefficient measuring device 140.

The friction coefficient measuring device 140 is constituted by a test pulley 141 and a load cell 142 provided on one side thereof, and the test pulley 141 is constituted by a rib pulley having a pulley diameter of 75 mm. The test pulley 141 is made of an iron-based material S45C. The v-ribbed test piece 143 extends horizontally from the load cell 142 and is wound around the test pulley 141, i.e., is disposed at a winding angle of 90 ° with respect to the test pulley 141.

The V-ribbed belts of examples 4-1 to 4-9 and comparative example 4 were cut to prepare a belt-shaped test piece 143, one end of which was fixed to the load cell 142, and the test pulley 141 was wound around the test piece 143 while the weight 144 was suspended and attached to the other end of the test piece. Then, the test pulley 141 was rotated at 43rpm in a direction to lower the weight 144 at an ambient temperature of 25 ℃, and the tension Tt received by the horizontal portion between the test pulley 141 and the load cell 142 of the test piece 143 was detected by the load cell 142 at 60 seconds after the start of the rotation. The tensile force Ts applied to the vertical portion of the weight 144 and the test pulley 141 of the test piece 143 was 17.15N, which is the weight of the weight 144. Then, based on the formula of Euler, the friction coefficient μ when the surface of the compressed rubber layer is dried is obtained by the following formula (2). In addition, θ is π/2.

[ formula 2]

Further, water is provided to the test pulley 141, a similar test is performed when the water is dry, and then a difference is obtained by subtracting the dry friction coefficient from the dry friction coefficient.

< belt running test for evaluating wear resistance >

Fig. 18 shows a pulley design of a belt running tester 150 for evaluating wear resistance. The belt running test machine 150 for evaluating wear resistance has a pulley diameter

A driving rib wheel 151 of 60mm and a driven rib wheel 152 of a pulley diameter of 60mm provided on the right side thereof. The driven rib pulley 152 is provided to be movable left and right so as to be able to receive an axial load (self weight DW) and apply tension to the v-ribbed belt B.

After measuring the belt mass, each of the v-ribbed belts of examples 4-1 to 4-9 and comparative example 4 was wound around a belt running tester 150 for evaluating wear resistance between the driving rib wheel 151 and the driven rib wheel 152, and the driven rib wheel 152 was subjected to an axial load of 490N to the right side to apply a tension to the v-ribbed belt B and a rotational load of 5.9kW (8PS) to rotate the driving rib wheel 151 at 3500rpm in a normal temperature environment to run the belt. Then, the running belt operation was stopped 24 hours after the start of the operation, the belt mass of the v-ribbed belt was measured, and the percentage of the mass reduction amount was determined.

< bending fatigue resistance evaluation Belt run test >

Fig. 19 shows a pulley design of a belt running tester 160 for evaluating bending fatigue resistance.

A belt running test machine 160 for evaluating bending fatigue resistance is provided with a pulley diameter

Drive rib wheel 161 of 60mm, pulley diameter disposed above it

A first driven rib wheel 162a of 60mm, disposed at the drivePulley diameter on right side of intermediate portion between movable rib pulley 161 and first driven rib pulley 162a

A second driven rib wheel 162b of 60mm and a pulley diameter provided at a distance from the right side of the intermediate portion between the driving rib wheel 161 and the first driven rib wheel 162a

A pair of guide wheels 163 of 50mm each. The first driven rib wheel 162a is provided to be movable up and down so as to be able to receive an axial load (self weight DW) and apply tension to the v-ribbed belt B. In the belt running test machine 160 for evaluating the bending fatigue resistance, the V-ribbed belt B is bent toward the back surface side, and the deformation of the V-rib tip is increased, thereby accelerating the bending fatigue.

Each of the v-ribbed belts of examples 4-1 to 4-9 and comparative example 4 was wound around a belt running tester 160 for evaluating bending fatigue resistance so that the compression rubber layer was in contact with the driving rib wheel 161, the first and second driven rib wheels 162a and 162B, and the back rubber layer was in contact with the guide wheel 163, and the first driven rib wheel 162a received an axial load of 588N upward, and the driving rib wheel 161 was rotated at 5100rpm at an ambient temperature of 70 ℃. Then, the running belt was periodically stopped, and whether or not the compression rubber layer was cracked was visually checked, and the running time of the belt until the occurrence of cracks was checked was regarded as the crack occurrence life.

(test evaluation results)

The results of the experiment are shown in table 2. In addition, the content of the cellulose ultrafine fibers means a mass part with respect to 100 mass parts of the rubber component, unless otherwise specified below.

< average fiber diameter, fiber diameter distribution >

The fiber diameters of the cellulose ultrafine fibers contained in the rubber compositions forming the compression rubber layers of the V-ribbed belts of examples 4-1 to 4-9 were distributed widely.

< coefficient of friction >

The friction coefficient of comparative example 4 was 0.6, while the friction coefficients of examples 4-1 to 4-9 were in the range of 0.6 to 1.1, and were the same as or slightly larger than comparative example 4. However, in all of examples 4-1 to 4-9, the amount of change (increase) between the friction coefficient in the dry state and the friction coefficient in the dry state was less than 0.9 in comparative example 4. In particular, in examples 4-3 to 4-6 in which the content of the cellulose microfiber was 5 parts by mass or more and examples 4-7 to 4-9 in which both the cellulose microfiber and the nylon staple fiber were included, the increase was-0.05 to 0.05 and was close to 0, and it was found that the increase in the friction coefficient when water was dried after water splashing could be suppressed. Even in the case of example 4-1 in which the content of the cellulose ultrafine fibers was the smallest (1 part by mass), the change in the friction coefficient was 0.5, which was a value close to half as compared with comparative example 4.

From this, it is found that by incorporating cellulose microfibers into the rubber composition forming the compression rubber layer, the change in the coefficient of friction after water splash can be suppressed. This effect can be exhibited even when only the cellulose microfiber is contained without the nylon staple fiber or when both the nylon staple fiber and the cellulose microfiber are contained.

< abrasion resistance >

The wear rate, which is the amount of mass reduction in comparative example 4, was 3.2%, whereas the wear resistance was improved to 2.8% in example 4-1 in which the content of the cellulose ultrafine fibers was 1 part by mass, and it was found that the wear resistance was improved as the content of the cellulose ultrafine fibers was increased (in examples 4-2 to 4-6, 2.7, 2.1, 1.9, 1.8, and 1.7 in this order). However, when the content of the cellulose microfiber exceeds 10 parts by mass, the improvement effect is small even if the content is further increased (examples 4-4 to 4-6).

In addition, the mass loss of comparative example 4 containing 15 parts by mass of nylon short fibers was 3.2%, and the mass loss of example 4-1 containing 1 part by mass of cellulose microfine fibers was 2.8%, compared with examples 4-7 containing 14 parts by mass of nylon short fibers and 1 part by mass of cellulose microfine fibers, which were 2.3%. That is, it is found that by containing both nylon short fibers and cellulose microfiber, the abrasion resistance can be further improved. It is understood from examples 4-7 to 4-9 that although the total content of the cellulose microfiber and the nylon staple fiber is the same, the abrasion resistance can be more effectively improved by increasing the content ratio of the cellulose microfiber.

< flexural fatigue resistance >

While the crack initiation life was 520 hours in comparative example 4 in which the content of nylon staple fibers was 15 parts by mass, the crack initiation life was 1205 hours and improved by two or more times in example 4-1 in which the content of cellulose microfiber was 1 part by mass. The crack-formation life was further improved by increasing the content of the cellulose microfiber to 3 parts by mass (example 4-2), but the crack-formation life was rather shortened by increasing the content (examples 4-3 to 4-6). However, even in examples 4 to 6 in which the content of the cellulose microfiber was 25 parts by mass, the crack initiation life was 900 hours, and the crack initiation life was significantly improved as compared with comparative example 4.

As a result, it was found that the bending fatigue resistance can be improved more than that of comparative example 4 when the cellulose ultrafine fibers and the nylon short fibers are used together. Further, the bending fatigue resistance can be improved by increasing the content ratio of the cellulose ultrafine fibers (examples 4-7 to 4-9).

As described above, by incorporating cellulose ultrafine fibers in the rubber composition forming the compression rubber layer, a v-ribbed belt with improved stability of the friction coefficient (suppression of change due to splash), wear resistance, bending fatigue resistance, and the like can be produced.

[ embodiment 3]

(Flat belt C)

Fig. 13 schematically shows a flat belt C according to embodiment 3. The flat belt C according to embodiment 3 is a power transmission member that requires a long life and is used under high load conditions such as driving applications of a blower, a compressor, a generator, and the like, driving applications of an auxiliary machine of an automobile, and the like. For the flat belt C, for example, the belt length is 600 to 3000mm, the belt width is 10 to 20mm, and the belt thickness is 2 to 3.5 mm.

The flat belt C according to embodiment 3 includes an inner rubber layer 121 on the inner circumferential side of the belt, an adhesive rubber layer 122 on the outer circumferential side of the belt, and an outer rubber layer 123 on the further outer circumferential side of the belt, and is integrally provided in a laminated manner to form a flat belt body 120. In the adhesive rubber layer 122, a core wire 124 is embedded so as to form a spiral having a pitch in the belt width direction at an intermediate portion in the belt thickness direction.

The inner rubber layer 121, the adhesive rubber layer 122, and the outer rubber layer 123 are each formed in a strip shape having a cross-sectional rectangular shape, and are formed of a rubber composition obtained by mixing and kneading an uncrosslinked rubber composition containing rubber components with various compounding agents under heat and pressure and crosslinking the rubber composition with a crosslinking agent. The thickness of the inner rubber layer 121 is preferably 0.3mm or more, more preferably 0.5mm or more, and further preferably 3.0mm or less, more preferably 2.5mm or less. The thickness of the adhesive rubber layer 122 may be, for example, 0.6 to 1.5 mm. The thickness of the outer rubber layer 123 may be, for example, 0.6 to 1.5 mm.

At least one of the rubber compositions forming the inner rubber layer 121, the adhesive rubber layer 122 and the outer rubber layer 123 contains cellulose-based ultrafine fibers having a fiber diameter distribution range of 50 to 500 nm. All of the rubber compositions forming the inner rubber layer 121, the adhesive rubber layer 122, and the outer rubber layer 123 preferably contain cellulose-based microfibers, but more preferably, at least the rubber composition forming the inner rubber layer 121 contains cellulose-based microfibers.

The rubber composition forming the inner rubber layer 121, the adhesive rubber layer 122, and the outer rubber layer 123 has the same structure as the rubber composition forming the compression rubber layer 111, the adhesive rubber layer 112, and the backing rubber layer 113 of embodiment 2. The cellulose-based microfiber also has the same structure as in embodiment 2.

The rubber composition forming the inner rubber layer 121, the adhesive rubber layer 122, and the outer rubber layer 123 may contain short fibers 126. In particular, it is preferable that the rubber composition forming the inner rubber layer 121 contains short fibers 126. In this case, the short fibers 126 are preferably contained in the inner rubber layer 121 so as to be oriented in the belt width direction. The short fibers 126 have the same structure as embodiment 2.

The core wire 124 has the same structure as that of embodiment 2.

According to the flat belt C of embodiment 3, since at least one of the rubber compositions forming the inner rubber layer 121, the adhesive rubber layer 122, and the outer rubber layer 123 constituting the flat belt body 120 contains cellulose-based ultrafine fibers having a fiber diameter distribution range of 50 to 500nm, excellent bending fatigue resistance can be obtained. In particular, when the rubber composition forming the inner rubber layer 121 constituting the contact portion contains cellulose-based ultrafine fibers, high abrasion resistance and a stable friction coefficient can be obtained.

(method for producing Flat Belt C)

A method for manufacturing the flat belt C according to embodiment 3 will be described with reference to fig. 14, 15, and 16.

The method for manufacturing the flat belt C according to embodiment 3 includes a material preparation step, a molding step, a crosslinking step, and a finishing step.

< Material preparation Process >

Uncrosslinked rubber sheets 121 ', 122 ', 123 ' for the inner rubber layer, the adhesive rubber layer, and the outer rubber layer were produced in the same manner as in embodiment 2, and contained cellulose-based microfibers. Further, a sheet containing no cellulose-based ultrafine fibers is produced by blending various rubber compounding agents into the rubber component, kneading the blend with a kneading machine such as a kneader or a banbury mixer, and molding the resulting uncrosslinked rubber composition into a sheet by calendering or the like.

Further, as in embodiment 2, the core wire 124' is subjected to an adhesion treatment.

< Molding Process >

As shown in fig. 14(a), after an uncrosslinked rubber sheet 121 'for the inner rubber layer is wound around the outer periphery of the cylindrical mold 145, an uncrosslinked rubber sheet 122' for the adhesive rubber layer is wound thereon.

Then, as shown in fig. 14(b), after winding a core wire 124 ' in a spiral shape on an uncrosslinked rubber sheet 122 ' for an adhesive rubber layer, the uncrosslinked rubber sheet 122 ' for the adhesive rubber layer is wound thereon.

Then, as shown in fig. 14(c), an uncrosslinked rubber sheet 123 'for the outer rubber layer is wound on the uncrosslinked rubber sheet 122' for the adhesive rubber layer. Thereby, a laminated molded body C' is formed on the cylindrical mold 145.

< crosslinking step >

Then, as shown in fig. 15, after covering the rubber sleeve 146 on the laminated molded body C' on the cylindrical mold 145, the laminated molded body is placed in a vulcanizing tank and sealed, and the cylindrical mold 145 is heated by high-temperature steam or the like and high-pressure is applied, thereby pressing the rubber sleeve 146 in the radial direction of the cylindrical mold 145 side. At this time, the uncrosslinked rubber composition of the laminate molding C 'flows, a crosslinking reaction of the rubber component occurs, and the core wires 124' undergo an adhesion reaction, whereby a cylindrical band plate S is formed on the cylindrical mold 145 as shown in fig. 16.

< grinding, Final working procedure >

In the polishing and finishing step, the cylindrical mold 145 is taken out of the vulcanizing tank, and after the cylindrical belt plate S formed on the cylindrical mold 145 is released, the outer circumferential surface and/or the inner circumferential surface thereof is polished to make the thickness uniform.

Finally, the belt plate S is cut to a predetermined width to produce a flat belt C.

Examples-

[ Flat belt ]

Flat belts of examples 5-1 to 5-6 and comparative examples 5-1 to 5-2 were prepared. Table 5 shows the details of each.

< example 5-1 >)

A master batch of cellulose microfiber/EPDM was prepared in the same manner as in example 4-1.

Then, the EPDM was masticated, and the master batch was put therein to be kneaded. The amount of the masterbatch added was 1 part by mass of the cellulose ultrafine fiber, based on 100 parts by mass of the total amount of EPDM.

Then, EPDM and cellulose microfiber were kneaded, 40 parts by mass of HAF carbon black (product name of Mitsubishi chemical company: DiabalackH), 5 parts by mass of processing oil (product name of SUN oil company: SUNPAR2280), 0.5 parts by mass of stearic acid (product name of New Nippon chemical company: stearic acid 50S) as a processing aid, 5 parts by mass of zinc oxide (product name of Nippon chemical company: three zinc oxide imidazoles) as a vulcanization acceleration aid, 2 parts by mass of a antiaging agent (product name of Dainippon chemical industry company: NocracMB) and 6 parts by mass of an organic peroxide (product name of Nippon oil company: PEROXYMONF-40 purity 40 mass%) as a crosslinking agent were added to 100 parts by mass of EPDM, and the mixture was continuously kneaded to prepare an uncrosslinked rubber composition.

Using this uncrosslinked rubber composition, a flat belt of example 5-1 was produced which had the same structure as that of embodiment 3 in which the inner rubber layer was formed so that the grain direction was the belt width direction.

For the V-ribbed belt of example 5-1, the belt length was 1118mm, the belt width was 10mm, and the belt thickness was 2.8 mm. The adhesive rubber layer and the outer rubber layer are formed of a rubber composition containing no cellulose ultrafine fiber and short fiber, and the core wire is formed of a twisted yarn of polyester fiber subjected to an adhesive treatment.

< example 5-2 >

A flat belt of example 5-2 was produced in the same manner as in example 5-1, except that the content of the cellulose ultrafine fibers was set to 3 parts by mass with respect to 100 parts by mass of the rubber component.

< example 5-3 >

A flat belt of example 5-3 was produced in the same manner as in example 5-1, except that the content of the cellulose ultrafine fibers was set to 5 parts by mass with respect to 100 parts by mass of the rubber component.

< example 5-4 >

The flat belts of examples 5 to 4 were produced in the same manner as in example 5-1, except that the content of the cellulose ultrafine fibers was 10 parts by mass with respect to 100 parts by mass of the rubber component.

< example 5-5 >

The flat belts of examples 5 to 5 were produced in the same manner as in example 5-1, except that the content of the cellulose ultrafine fibers was set to 15 parts by mass with respect to 100 parts by mass of the rubber component.

< example 5-6 >

The flat belts of examples 5 to 6 were produced in the same manner as in example 5-1, except that the content of the cellulose ultrafine fibers was set to 25 parts by mass with respect to 100 parts by mass of the rubber component.

< comparative example 5-1 >

A flat belt of comparative example 5-1 was produced in the same manner as in example 5-1, except that the rubber composition forming the inner rubber layer did not contain cellulose ultrafine fibers.

< comparative example 5-2 >

A flat belt of comparative example 5-2 was produced in the same manner as in example 5-1, except that the rubber composition forming the inner rubber layer contained no cellulose ultrafine fibers and 5 parts by mass of nylon short fibers per 100 parts by mass of the rubber component.

[ Table 5]

(test evaluation method)

< average fiber diameter, fiber diameter distribution >

Samples of the rubber compositions constituting the inner rubber layers of the flat belts of examples 5-1 to 5-6 were collected, and the average fiber diameter of the cellulose ultrafine fibers and the maximum and minimum values of the fiber diameters were determined by the same method as in test evaluation 1.

< test for evaluating Belt running for Friction and wear characteristics >

Fig. 20 shows a pulley design of a belt running test machine 170 for evaluating friction and wear characteristics.

A belt running test machine 170 for evaluating friction and wear characteristics is provided with a pulley diameter

A driving flat wheel 171 of 120mm, arranged thereonA first driven flat pulley 172 having a square pulley diameter of 120mm, and a pulley diameter provided on the right side of the middle position in the vertical direction

A second driven flat wheel 173 of 50 mm. The second driven flat pulley 173 is provided to be movable in the left-right direction so as to be able to receive an axial load (self weight DW) and apply tension to the flat belt C.

The flat belts C of examples 5-1 to 5-6 and comparative examples 5-1 to 5-2 were wound around a drive flat wheel 171 and first and second driven flat wheels 72 and 73 of a belt running test machine 170 for evaluating friction and wear characteristics, and the second driven flat wheel 173 was subjected to an axial load of 98N toward the right side to apply a tension to the flat belts C, and a rotational load of 8.8kW was applied to the first driven flat wheel 172 to rotate the drive flat wheel 171 at a rotational speed of 4800rpm at an ambient temperature of 120 ℃ to run the belts. Then, the belt was stopped 24 hours after the start of the operation, and the friction coefficient of the surface of the inner rubber layer after the belt operation was obtained by the same method as in test evaluation 1 using the friction coefficient measuring device 140 shown in fig. 17. In addition, as the test pulley 141, a pulley diameter is used

Is a 65mm flat wheel.

The belt running time was set to 500 hours, the same test was performed, and the amount of change in the friction coefficient was calculated as compared with the case where the belt running time was set to 24 hours.

Then, the running surfaces of the driving flat wheel 171 and the first and second driven flat wheels 72 and 73 after the belt was run for 24 hours were visually observed, and the surface state was evaluated from a sensory point of view, and the adhesive wear occurrence index was numerically determined in the following manner based on the adhesion amount and texture of the rubber.

In the case of a residue-like substance to which an adhesive erasable rubber is attached: 100

In the presence of powdery accretions: 50,

in the case of no adhering matter: 0

Among them, the rubber which is difficult to aggregate is powdery and tends to fall off from the belt surface. Even if the abrasion resistance is good, if the state of the abrasion powder is poor and the abrasion powder is foreign matter, the product value is low.

< belt running test for evaluating wear resistance >

Fig. 21 shows a pulley design of a belt running test machine 180 for evaluating wear resistance.

The belt running test machine 180 for evaluating wear resistance includes a pulley diameter

A driving flat wheel 181 of 100mm and a driven flat wheel 182 of 100mm diameter provided on the left side thereof with a pulley. The drive pulley 181 is provided to be movable in the left-right direction so as to be able to receive an axial load (self weight DW) and apply tension to the flat belt C.

Each flat belt C of examples 5-1 to 5-6 and comparative examples 5-1 to 5-2 was wound between the driving flat wheel 181 and the driven flat wheel 182 of the belt running tester 180 for evaluating abrasion resistance after measuring the belt mass, and the driving flat wheel 181 received an axial load of 300N to the right side, and applied a tension to the flat belt C, and received a rotational torque of 12N · m on the driven flat wheel 182, and the driving flat wheel 181 was rotated at a rotational speed of 2000rpm at an ambient temperature of 100 ℃ to run the belt. Then, the belt was stopped 24 hours after the start of the operation, the belt mass of the flat belt C was measured, the mass loss was determined, and the percentage of mass loss of comparative example 5-1 was calculated.

(test evaluation results)

Table 5 shows the experimental results. In addition, the content of the cellulose ultrafine fibers means a mass part with respect to 100 mass parts of the rubber component, unless otherwise specified below.

< average fiber diameter, fiber diameter distribution >

From this, it is clear that the fiber diameters of the cellulose ultrafine fibers contained in the rubber compositions forming the inner rubber layers of the flat belts of examples 5-1 to 5-6 are distributed widely.

< friction and wear characteristics >

Coefficient of friction

The belt of comparative example 5-1 had a friction coefficient of 0.85 after 24 hours of operation, while examples 5-1 and 5-2 were 0.85 in the same manner, and the friction coefficient was not changed since the content of the cellulose microfiber relative to 100 parts by mass of the rubber component was about 1 to 3 parts by mass. When the content of the cellulose microfine fibers was further increased (examples 5-3 to 5-6), the friction coefficient was lowered, and it was 0.6 at 25 parts by mass (examples 5-6).

In comparative example 5-2 in which 5 parts by mass of nylon staple fiber was blended, the friction coefficient was 0.75, which is the same as that in example 5-4 in which the content of cellulose microfiber was 10 parts by mass.

The friction coefficient after 500 hours of belt operation was decreased by 0.35 and 0.25 in the order of comparative example 5-1 and comparative example 5-2, compared with the friction coefficient after 24 hours of belt operation, whereas the maximum decrease was 0.15 in examples 5-1 to 5-6 (examples 5-1 and 2-2). From this, it is seen that the decrease amount is smaller if the content of the cellulose microfiber is larger, and that the friction coefficients after 24 hours and 500 hours of belt operation are the same if the content is 10 parts by mass or more (examples 5-4 to 5-6).

From this, it was found that a flat belt having a small change in friction coefficient with time could be obtained by forming the inner rubber layer with a rubber composition containing cellulose ultrafine fibers.

Index of adhesive wear occurrence

In contrast to the evaluation values of 100 and 90 for the adhesive wear occurrence indexes of comparative example 5-1 and comparative example 5-2, in the case of using the rubber composition containing the cellulose microfiber, the adhesive wear occurrence index was 45 even in example 5-1 having the smallest content (1 part by mass), which was found to be significantly improved. The adhesive wear occurrence index can be further improved by increasing the content, and in examples 5 to 6 containing 25 parts by mass of the cellulose microfiber, the evaluation value was 10 (less adhering matter to the belt surface and more powdery matter with lower adhesiveness).

In the case of comparative example 5-2 containing nylon short fibers, there was an improvement, but not a significant effect, compared to comparative example 5-1.

From this, it is found that the index of occurrence of adhesive wear of the flat belt can be improved by forming the inner rubber layer with a rubber composition containing cellulose ultrafine fibers.

< abrasion resistance >

The abrasion resistance evaluation values of comparative example 5-1 and comparative example 5-2 were 100, whereas example 5-1, in which the content of the cellulose microfiber was 1 part by mass, was improved to 65, and the evaluation value could be further improved by further increasing the content. Among them, when the content of the cellulose microfiber is in the range of 3 to 25 parts by mass (examples 5-2 to 5-6), the evaluation value is 50 or 45, and the content of the cellulose microfiber tends to be increased, but the improvement in abrasion resistance tends to be saturated.

[ embodiment 4]

(toothed belt B)

Fig. 22 shows a toothed belt B according to embodiment 4.

The toothed belt B according to embodiment 4 includes an endless toothed belt body 310 formed of a rubber composition. The toothed belt body 310 has a flat belt-like base portion 311a and a plurality of teeth portions 311b integrally provided at a fixed pitch at intervals in the belt length direction on one side, i.e., the surface on the inner peripheral side. A tooth-side reinforcing cloth 312 is attached to the toothed belt main body 310 so as to cover the tooth-side surface. Further, a core wire 313 is embedded on the inner peripheral side of the base portion 311a of the toothed belt main body 310 so as to form a spiral having a pitch in the belt width direction. The toothed belt B according to embodiment 4 is suitable for use as a power transmission member of a belt transmission device for a machine tool or the like, particularly a belt transmission device for a machine tool having an operating time of about 3 to 120 hours per year, for example. The toothed belt B according to embodiment 4 has, for example, a belt length of 500 to 3000mm, a belt width of 10 to 200mm, and a belt thickness of 3 to 20 mm. The tooth portion 311b has a width of 0.63 to 16.46mm, a height of 0.37 to 9.6mm, and a pitch of 1.0 to 31.75mm, for example.

The tooth portion 311b of the toothed belt main body 310 may be a trapezoidal tooth having a trapezoidal side shape, a semicircular round tooth, or another shape. The tooth portion 311b may be formed as a helical tooth extending in the belt width direction or in a direction inclined with respect to the belt width direction.

The toothed belt body 310 is formed from a rubber composition obtained by adding a cellulose-based microfiber having a fiber diameter distribution range of 50 to 500nm to a rubber component, kneading the mixture with various rubber compounding agents, heating and pressurizing the resulting uncrosslinked rubber composition, and crosslinking the rubber composition with a crosslinking agent. As described above, the rubber composition forming the toothed belt body 310 contains the cellulose-based microfiber having a fiber diameter distribution range of 50 to 500nm, and thus, the durability of the toothed belt B can be improved. The term "ultrafine fibers" as used herein means fibers having a fiber diameter of 1.0 μm or less.

Examples of the rubber component of the rubber composition forming the toothed belt main body 310 include hydrogenated acrylonitrile rubber (H-HBR), hydrogenated acrylonitrile rubber (H-HBR) reinforced with a metal salt of unsaturated carboxylic acid, ethylene-propylene copolymer (EPR), ethylene-propylene-diene terpolymer (EPDM), ethylene-octene copolymer, ethylene-butene copolymer, and other ethylene- α -olefin elastomers, Chloroprene Rubber (CR), and chlorosulfonated polyethylene rubber (CSM). One or a mixture of two or more of the rubber components of the rubber composition constituting the toothed belt main body 310 is preferable.

In the H-HBR strengthened by the metal salt of an unsaturated carboxylic acid, examples of the unsaturated carboxylic acid include methacrylic acid, acrylic acid, and the like, and examples of the metal include zinc, calcium, magnesium, aluminum, and the like.

Cellulose-based microfibers are fiber materials based on cellulose microfibers that are composed of skeletal components of plant cell walls obtained by finely disassembling plant fibers. Examples of the raw material plant of cellulose-based microfiber include wood, bamboo, rice (straw), potato, sugarcane (bagasse), waterweed, and seaweed. Among them, wood is preferable.

The cellulose-based ultrafine fiber may be the cellulose ultrafine fiber itself, or may be a hydrophobized cellulose ultrafine fiber subjected to a hydrophobization treatment. In addition, as the cellulose-based microfiber, the cellulose microfiber itself and the hydrophobized cellulose microfiber may be used together. From the viewpoint of dispersibility, the cellulose-based ultrafine fibers preferably include hydrophobized cellulose ultrafine fibers. Examples of the hydrophobized cellulose microfine fibers include cellulose microfine fibers obtained by replacing a part or all of the hydroxyl groups of cellulose with hydrophobic groups, and cellulose microfine fibers subjected to a hydrophobization surface treatment using a surface treatment agent.

In the cellulose-based microfiber, it is preferable that the fiber diameter distribution is wide and the fiber diameter distribution range is 50 to 500nm in order to improve the durability of the toothed belt B. The lower limit of the distribution of the fiber diameter is preferably 20nm or less, more preferably 10nm or less, from the above-mentioned viewpoint. From the same viewpoint, the upper limit is preferably 700nm or more, and more preferably 1 μm or more. The distribution range of the fiber diameter of the cellulose-based microfiber preferably includes 20nm to 700nm, and more preferably 10nm to 1 μm.

The average fiber diameter of the cellulose-based microfine fibers contained in the rubber composition constituting the toothed belt body 310 is preferably 10nm or more, more preferably 20nm or more, and further preferably 700nm or less, more preferably 100nm or less.

A sample of the rubber composition constituting the toothed belt main body 310 was frozen and pulverized, and then the cross section thereof was observed with a Transmission Electron Microscope (TEM), and the fiber diameter was measured by selecting 50 cellulose-based ultrafine fibers arbitrarily, and the fiber diameter distribution of the cellulose-based ultrafine fibers was obtained based on the measurement result. The average of the fiber diameters of the arbitrarily selected 50 cellulose microfibers was determined as the average fiber diameter of the cellulose microfibers.

The cellulose-based ultrafine fiber may be a cellulose-based ultrafine fiber having a high aspect ratio produced by a mechanical defibration method, or may be a needle-like crystal produced by a chemical defibration method. Among them, the production is preferably carried out by a mechanical defibration method. As the cellulose-based microfiber, a cellulose-based microfiber produced by a mechanical defibration method and a cellulose-based microfiber produced by a chemical defibration method may be used in combination. Examples of the defibrating apparatus used in the mechanical defibrating method include a kneader such as a twin-screw kneader, a high-pressure homogenizer, a mill, and a sand mill. Examples of the treatment for the chemical defibration method include acid hydrolysis treatment.

The content of the cellulose-based ultrafine fibers in the rubber composition forming the toothed belt body 310 is preferably 1 part by mass or more, more preferably 3 parts by mass or more, further preferably 5 parts by mass or more, and further preferably 30 parts by mass or less, more preferably 20 parts by mass or less, further preferably 10 parts by mass or less, relative to 100 parts by mass of the rubber component, from the viewpoint of improving the durability of the toothed belt B.

Examples of the rubber compounding agent include a reinforcing material, a processing aid, a vulcanization accelerator aid, a plasticizer, an auxiliary crosslinking agent, a vulcanization accelerator, an antioxidant, and the like.

Examples of the carbon black as the reinforcing material include channel black, SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, N-234 and other furnace blacks, FT, MT and other thermal blacks, acetylene black and the like. Silicon dioxide can also be mentioned as a reinforcing material. The reinforcing material is preferably one or two or more thereof. The content of the reinforcing material may be, for example, 20 to 60 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of the plasticizer include dialkyl phthalates such as dibutyl phthalate (DBP) and dioctyl phthalate (DOP), dialkyl adipates such as dioctyl adipate (DOA), and dialkyl sebacates such as dioctyl sebacate (DOS). The plasticizer is preferably one or two or more of them. The content of the plasticizer may be, for example, 0.1 to 40 parts by mass with respect to 100 parts by mass of the rubber component.

Examples of the auxiliary crosslinking agent include liquid rubbers such as liquid NBR. The auxiliary crosslinking agent is preferably one or two or more. The content of the co-crosslinking agent may be, for example, 3 to 7 parts by mass per 100 parts by mass of the rubber component.

Examples of the vulcanization accelerator include thiurams (e.g., TETD, TT, TRA, etc.), thiazoles (e.g., MBT, MBTs, etc.), sulfenamides (e.g., CZ, etc.), dithiocarbamates (e.g., BZ-P, etc.), and the like. The vulcanization accelerator is preferably one or two or more of them. The content of the vulcanization accelerator may be, for example, 2 to 5 parts by mass per 100 parts by mass of the rubber component of the rubber composition.

Examples of the antioxidant include amine-based antioxidants, diamine-based antioxidants, phenol-based antioxidants, and the like. The aging inhibitor is preferably one or more of these. The content of the antioxidant may be, for example, 0.1 to 5 parts by mass per 100 parts by mass of the rubber component.

The rubber composition forming the toothed belt main body 310 may contain short fibers having a fiber diameter of 10 μm or more.

The tooth portion side reinforcing fabric 312 may be formed of a fabric such as a woven fabric, a knitted fabric, or a nonwoven fabric made of cotton, polyamide fiber, polyester fiber, or aramid fiber. The tooth portion side reinforcing cloth 312 preferably has extensibility. The thickness of the tooth-side reinforcing cloth 312 is, for example, 0.3 to 2.0 mm. The tooth-side reinforcing cloth 312 is subjected to an adhesion process for adhesion to the toothed belt main body 310.

The core wire 313 is formed by twisted threads made of glass fibers, aromatic polyamide fibers, polyester fibers, or the like. The diameter of the core wire 313 may be, for example, 0.5 to 2.5mm, and the dimension between the centers of the core wires adjacent to each other in the cross section may be, for example, 0.05 to 0.20 mm. The core wire 313 is subjected to an adhesion treatment for imparting adhesion to the toothed belt main body 310.

According to the toothed belt B of embodiment 4 configured as described above, since the rubber composition for forming the toothed belt main body 310 including the base portion 311a and the tooth portions 311B contains the cellulose-based ultrafine fibers having the fiber diameter distribution range of 50 to 500nm, an excellent reinforcing effect can be obtained, and particularly, the tooth portions 311B can be prevented from being broken, and excellent oil resistance can be obtained, and as a result, high durability can be obtained.

(method of manufacturing toothed Belt B)

A method for manufacturing the toothed belt B according to embodiment 4 will be described with reference to fig. 23 to 26.

Fig. 23 shows a belt molding die 320 for manufacturing the toothed belt B according to embodiment 4.

The belt molding die 320 has a cylindrical shape, and teeth forming grooves 321 extending in the axial direction are formed on the outer circumferential surface thereof at regular intervals in the circumferential direction.

The method of manufacturing a toothed belt according to embodiment 4 includes a material preparation step, a molding step, a crosslinking step, and a finishing step.

< Material preparation Process >

An uncrosslinked rubber sheet 311' for the base and the teeth

Among them, examples of the method for dispersing the cellulose-based microfine fibers as the rubber component include the following methods: a dispersion (gel) in which a cellulose-based ultrafine fiber is dispersed in water is put into a rubber component masticated by an open mill, and water is vaporized while kneading the components; a cellulose-based microfiber/rubber master batch obtained by mixing a dispersion (gel) in which cellulose-based microfiber is dispersed in water with a rubber latex and vaporizing water is put into a masticated rubber component; a step of adding a cellulose-based microfiber/rubber master batch obtained by mixing a dispersion liquid in which cellulose-based microfiber is dispersed in a solvent with a solution in which a rubber component is dissolved in a solvent and vaporizing the solvent to the masticated rubber component; freeze-drying and pulverizing a dispersion (gel) in which cellulose-based ultrafine fibers are dispersed in water, and then adding the resultant to a masticated rubber component; and adding the hydrophobized cellulose-based ultrafine fiber to the masticated rubber component.

Then, the rubber component and the cellulose-based microfiber were kneaded together, and various rubber compounding agents were added thereto, followed by further kneading.

Then, the obtained uncrosslinked rubber composition is molded into a sheet shape by calendar molding or the like, to prepare an uncrosslinked rubber sheet 311' for the base portion and the tooth portion.

Tooth-side reinforcing cloth 312' -)

The tooth-side reinforcing fabric 312' is subjected to bonding treatment. Specifically, the tooth-side reinforcing fabric 312' is subjected to RFL adhesion treatment in which it is immersed in an RFL aqueous solution and heated. Further, if necessary, a base adhesion treatment is performed by dipping in a base adhesion treatment liquid and heating before the RFL adhesion treatment. Further, after the RFL adhesion treatment, an impregnated rubber paste adhesion treatment of impregnating the rubber paste and drying and/or a coated rubber paste adhesion treatment of coating the rubber paste on the surface of the toothed belt main body 310 side and drying are performed as necessary.

Then, both ends of the tooth-side reinforcing fabric 312' subjected to the bonding process are joined to form a cylindrical shape.

-core wire 313-

The core wire 313' is subjected to an adhesion treatment. Specifically, the core wire 313' is subjected to RFL adhesion treatment of dipping in a resorcinol-formalin-latex aqueous solution (hereinafter, referred to as an "RFL aqueous solution") and heating. Further, as necessary, a base adhesion treatment of dipping in a base adhesion treatment liquid and heating is performed before the RFL adhesion treatment and/or a rubber paste adhesion treatment of dipping in a rubber paste and drying is performed after the RFL adhesion treatment.

< Molding Process >

As shown in fig. 24, the outer periphery of the belt molding die 320 is covered with a cylindrical tooth-side reinforcing fabric 312 ', on which the core wire 313 ' is wound in a spiral shape, and then an uncrosslinked rubber sheet 311 ' is wound. At this time, a laminated molded body B' is formed on the tape molding die 320. The uncrosslinked rubber sheet 311' may be used so that the grain direction corresponds to the belt length direction, or may be used so that the grain direction corresponds to the belt width direction.

< crosslinking step >

As shown in fig. 25, after a release paper 322 is wound around the outer periphery of the laminated molded body B', a rubber sleeve 323 is covered on the top surface thereof, and the laminated molded body is placed in a vulcanizing tank and sealed, and high-temperature and high-pressure steam is filled into the vulcanizing tank and kept for a predetermined molding time. At this time, the uncrosslinked rubber sheet of the laminated molded body B ' presses the tooth-side reinforcing cloth 312 and flows into the tooth-forming grooves 321 of the belt molding die 320, and is crosslinked and integrated with the tooth-side reinforcing cloth 312 ' and the core wires 313 ', and finally, as shown in fig. 26, the cylindrical belt plate S is molded. The molding temperature of the strip S may be, for example, 100 to 180 ℃, the molding pressure may be, for example, 0.5 to 2.0MPa, and the molding time may be, for example, 10 to 60 minutes.

< Final working procedure >

The inside of the vulcanizing tank is depressurized, the sealing is released, the belt plate S molded between the belt molding die 320 and the rubber sleeve 323 is taken out, the belt plate S is separated from the die, the back surface side thereof is polished to adjust the thickness, and the belt plate S is cut into a wheel shape with a predetermined width to manufacture the toothed belt B.

[ embodiment 5]

(toothed belt B)

The appearance structure of the toothed belt B according to embodiment 5 is the same as that of embodiment 4, and therefore, the following description is made with reference to fig. 22.

In the toothed belt B according to embodiment 5, the rubber composition forming the base portion 311a of the toothed belt body 310 contains cellulose-based ultrafine fibers having a fiber diameter distribution range of 50 to 500 nm. On the other hand, the rubber composition forming the tooth portion 311b does not contain cellulose-based microfiber. The rubber composition forming the tooth 311b may contain cellulose-based ultrafine fibers having a fiber diameter distribution range not including 50 to 500 nm.

The other structure is the same as embodiment 4.

According to the toothed belt B of embodiment 5 having the above configuration, since the rubber composition forming the base portion 311a contains the cellulose-based ultrafine fibers having the fiber diameter distribution range of 50 to 500nm, it is possible to obtain the excellent reinforcing effect and to obtain the excellent oil resistance, and as a result, it is possible to obtain the high durability.

(method of manufacturing toothed Belt B)

In the method for manufacturing the toothed belt B according to embodiment 5, in the material preparation step, as in embodiment 4, the uncrosslinked rubber sheet 311 a' for the base portion, which contains the cellulose-based microfiber having a fiber diameter distribution range of 50 to 500nm, is manufactured. Further, the uncrosslinked rubber 311 b' for the tooth portion formed in the shape of the tooth portion forming groove 321 of the belt forming die 320 is prepared by mixing various rubber compounding agents into the rubber component and using an uncrosslinked rubber composition containing cellulose-based ultrafine fibers having a fiber diameter distribution range of 50 to 500nm obtained by kneading with a kneading machine such as a kneader or a banbury mixer.

Then, in the molding process, as shown in fig. 27, after a cylindrical tooth-side reinforcing cloth 312 ' is laid over the outer periphery of the belt molding die 320 and along the tooth forming grooves 321, as shown in fig. 28, an uncrosslinked rubber 311B ' for the tooth portions is embedded in each tooth forming groove 321, as shown in fig. 29, and a core wire 313 ' is wound in a spiral shape on the upper surface thereof, and then an uncrosslinked rubber sheet 311a ' for the base portion is wound on the upper surface thereof, thereby forming a laminated molded body B '. In the crosslinking step, the non-crosslinked rubber 311B ' for the tooth portion and the non-crosslinked rubber piece 311a ' for the base portion of the laminated molded body B ' are crosslinked, and they are compositely integrated with the tooth-side reinforcing fabric 312 ' and the core wire 313 ', and finally, the cylindrical band plate S similar to fig. 26 of embodiment 4 is molded.

The other methods are the same as embodiment 4.

[ embodiment 6]

(toothed belt B)

The appearance structure of the toothed belt B according to embodiment 6 is the same as that of embodiment 4, and therefore, the following description is made with reference to fig. 22.

In the toothed belt B according to embodiment 6, the rubber composition forming the tooth portions 311B of the toothed belt main body 310 contains cellulose-based ultrafine fibers having a fiber diameter distribution range of 50 to 500 nm. On the other hand, the rubber composition forming the base portion 311a does not contain cellulose-based ultrafine fibers. The rubber composition forming the base 311a may contain cellulose-based ultrafine fibers having a fiber diameter distribution range not including 50 to 500 nm.

The other structure is the same as embodiment 4.

According to the toothed belt B of embodiment 6 having the above configuration, since the rubber composition forming the tooth portions 311B contains the cellulose-based ultrafine fibers having the fiber diameter distribution range of 50 to 500nm, it is possible to obtain an excellent reinforcing effect thereof, and in particular, it is possible to suppress the chipping of the tooth portions 311B, and it is possible to obtain excellent oil resistance, and as a result, it is possible to obtain high durability.

(method of manufacturing toothed Belt B)

In the method of manufacturing the toothed belt B according to embodiment 6, in the material preparation step, as in embodiment 4, the uncrosslinked rubber composition for the teeth, which contains the cellulose-based microfiber having a fiber diameter distribution range of 50 to 500nm, is kneaded and made into the uncrosslinked rubber 311B' for the teeth, which is formed in the shape of the tooth forming grooves 321 of the belt forming die 320. Further, various rubber compounding agents are compounded into the rubber component, and the uncrosslinked rubber composition containing no cellulose-based ultrafine fibers obtained by kneading with a kneader such as a kneader or a banbury mixer is molded into a sheet by calendar molding or the like to prepare an uncrosslinked rubber sheet 311 a' for the base.

Then, in the molding step, similarly to fig. 27 of embodiment 5, after the cylindrical tooth-side reinforcing cloth 312 ' is laid over the outer periphery of the belt molding die 320 and is provided along the tooth-forming grooves 321, similarly to fig. 28, the non-crosslinked rubber 311B ' for the tooth portion is fitted into each tooth-forming groove 321, and the core wire 313 ' is wound spirally on the upper surface thereof, and then the non-crosslinked rubber piece 311a ' for the base portion is wound on the upper surface thereof, thereby forming a laminated molded body B '. In the crosslinking step, the non-crosslinked rubber 311B ' for the tooth portion and the non-crosslinked rubber piece 311a ' for the base portion of the laminated molded body B ' are crosslinked, and they are compositely integrated with the tooth-side reinforcing fabric 312 ' and the core wire 313 ', and finally, the cylindrical band plate S similar to fig. 26 of embodiment 4 is molded.

The other methods are the same as embodiment 4.

[ embodiment 7]

(toothed belt B)

The appearance structure of the toothed belt B according to embodiment 7 is the same as that of embodiment 4, and therefore, the following description is made with reference to fig. 22.

In the toothed belt B according to embodiment 7, the tooth-side reinforcing fabric 312 is subjected to RFL adhesion treatment in which it is immersed in an RFL aqueous solution and heated. Thereby, as shown in fig. 30, the tooth-side reinforcing cloth 312 is adhered to the toothed belt main body 310 via an RFL adhesive layer 314 formed by RFL adhesion treatment. Before the RFL adhesion treatment, the RFL is subjected to a primer adhesion treatment by dipping the RFL in a primer adhesion treatment liquid composed of a solution obtained by dissolving a primer adhesion treatment agent such as an epoxy resin or an isocyanate resin (block isocyanate) in a solvent such as toluene or a dispersion liquid dispersed in water and heating the RFL, and the primer adhesion layer is preferably provided under the RFL adhesion layer 314. After the RFL adhesion treatment, either or both of an impregnated rubber paste adhesion treatment in which the rubber paste is impregnated and dried and a rubber paste application adhesion treatment in which the rubber paste is applied and dried to the surface of the toothed belt main body 310 side may be performed, and the rubber paste adhesion layer may be provided on the RFL adhesion layer 314.

The RFL adhesive layer 314 is formed of solid components contained in an RFL aqueous solution, and contains resorcinol-formalin resin (RF resin) and rubber components derived from rubber latex. The RFL adhesive layer 314 contains cellulose-based ultrafine fibers having a fiber diameter distribution range of 50 to 500 nm. The cellulose-based microfiber included in the RFL adhesive layer 314 has the same structure as the cellulose-based microfiber included in the toothed belt main body 310 according to embodiment 4. As described above, since the RFL adhesive layer 314 contains the cellulose-based ultrafine fibers having the fiber diameters distributed in a range of 50 to 500nm, a high adhesive force of the tooth-side reinforcing fabric 312 to the toothed belt main body 310 can be obtained.

In the RFL adhesive layer 314, the cellulose-based ultrafine fibers are not oriented in a specific direction, i.e., are randomly oriented.

The content of the cellulose-based ultrafine fibers in the RFL adhesive layer 314 is preferably 0.5 mass% or more, more preferably 1.0 mass% or more, further preferably 2.0 mass% or more, and further preferably 12 mass% or less, more preferably 10 mass% or less, further preferably 8 mass% or less, from the viewpoint of high adhesion of the tooth-side reinforcing fabric 312 to the toothed belt main body 310.

The content of the cellulose-based ultrafine fiber in the RFL adhesive layer 314 with respect to 100 parts by mass of the rubber component is preferably 1 part by mass or more, more preferably 3 parts by mass or more, further preferably 5 parts by mass or more, and further preferably 30 parts by mass or less, more preferably 20 parts by mass or less, further preferably 10 parts by mass or less, from the viewpoint of high adhesiveness of the tooth-side reinforcing cloth 312 to the toothed belt body 310.

It is preferable that the RFL adhesive layer 314 does not contain short fibers having a fiber diameter of 10 μm or more, but the short fibers may be contained within a range that does not affect the adhesiveness of the tooth-side reinforcing cloth 312 to the toothed belt main body 310.

In the rubber composition forming the base portion 311a of the toothed belt main body 310, the cellulose-based microfiber may be contained or may not be contained, as in embodiments 4 and 5. The rubber composition forming the tooth portion 311b of the toothed belt main body 310 may or may not contain cellulose-based microfiber as in embodiments 4 and 6.

The other structure is the same as embodiment 4.

According to the toothed belt B of embodiment 7 configured as described above, the RFL adhesive layer 314 provided between the tooth-side reinforcing cloth 312 and the toothed belt main body 310 contains the cellulose-based ultrafine fibers having the fiber diameter distribution range of 50 to 500nm, and therefore, a high adhesive force of the tooth-side reinforcing cloth 312 to the toothed belt main body 310 can be obtained, and an excellent reinforcing effect can be obtained, and particularly, chipping of the tooth portion 311B can be suppressed, and as a result, high durability can be obtained.

(method of manufacturing toothed Belt B)

In the method of manufacturing the toothed belt B according to embodiment 7, in the material preparation step, when the tooth portion side reinforcing cloth 312 'is manufactured, the tooth portion side reinforcing cloth 312' is subjected to the adhesion treatment. Specifically, the tooth-side reinforcing fabric 312' is subjected to RFL adhesion treatment in which it is immersed in an RFL aqueous solution and heated. Further, it is preferable to perform a base adhesion treatment by dipping in a base adhesion treatment liquid and heating before the RFL adhesion treatment. Further, after the RFL adhesion treatment, one or both of an impregnated rubber paste adhesion treatment in which the rubber paste is impregnated and dried and a coated rubber paste adhesion treatment in which the rubber paste is coated and dried on the surface of the toothed belt main body 310 side may be performed.

Substrate bonding treatment

The base adhesion treatment liquid is, for example, a solution obtained by dissolving a base adhesion treatment agent such as an epoxy resin or an isocyanate resin (blocked isocyanate) in a solvent such as toluene or a dispersion liquid obtained by dispersing the base adhesion treatment agent in water. The liquid temperature of the substrate bonding treatment liquid may be, for example, 20 to 30 ℃. The solid content concentration of the base adhesion treatment liquid is preferably 20% by mass or less.

The immersion time in the substrate adhesion treatment liquid may be, for example, 1 to 3 seconds. The heating temperature (furnace temperature) after the immersion in the substrate bonding treatment liquid is, for example, 200 to 250 ℃. The heating time (residence time in the furnace) may be, for example, 1 to 3 minutes. The number of times of the substrate bonding treatment may be one or two or more. The base adhesion treatment agent is applied to the tooth-side reinforcing cloth 312 ', but the amount of application (amount of application) may be, for example, 0.5 to 8% by mass based on the mass of the fiber material forming the tooth-side reinforcing cloth 312'.

RFL adhesion treatment

The RFL aqueous solution is an aqueous solution obtained by mixing a rubber latex and a dispersion (gel) of cellulose-based ultrafine fibers dispersed in water with an initial condensation product of resorcinol and formaldehyde. The liquid temperature of the RFL aqueous solution may be, for example, 20 to 30 ℃.

The molar ratio of resorcinol (R) to formalin (F) may be, for example, R/F1/1 to 1/2. Examples of the rubber latex include vinylpyridine-styrene-butadiene rubber latex (Vp-St-SBR), chloroprene rubber latex (CR), and chlorosulfonated polyethylene rubber latex (CSM). The solid content mass ratio of the initial condensation product (RF) of resorcinol and formaldehyde to the rubber latex (L) may be, for example, 1/5 to 1/20 in terms of RF/L.

The solid content concentration of the RFL aqueous solution is preferably 6.0 mass% or more, more preferably 9.0 mass% or more, and further preferably 20 mass% or less, more preferably 15 mass% or less.

The dipping time in the RFL aqueous solution may be, for example, 1 to 3 seconds. The heating temperature (furnace temperature) after the RFL solution immersion may be, for example, 100 to 180 ℃. The heating time (residence time in the furnace) may be, for example, 1 to 5 minutes. The number of RFL adhesion treatments may be one or more than two. The RFL adhesive layer 314 is attached to the tooth-side reinforcing cloth 312 ', but the amount of attachment (amount of application) may be, for example, 2 to 5 mass% based on the mass of the fiber material forming the tooth-side reinforcing cloth 312'.

The other methods are the same as embodiment 4.

[ embodiment 8]

The appearance structure of the toothed belt B according to embodiment 8 is the same as that of embodiment 4, and therefore the following description is made with reference to fig. 22.

In the toothed belt B according to embodiment 8, the tooth-side reinforcing fabric 312 is subjected to one or two of RFL adhesion treatment in which it is immersed in an RFL aqueous solution and heated, rubber paste impregnation adhesion treatment in which it is immersed in a rubber paste and dried, and rubber paste application adhesion treatment in which a rubber paste is applied and dried to the surface of the toothed belt main body 310 side. Thereby, as shown in fig. 31, the tooth-side reinforcing cloth 312 is bonded to the toothed belt main body 310 via an RFL bonding layer 314 formed by an RFL bonding treatment and a rubber paste bonding layer 315 formed by a rubber paste bonding treatment. It is also preferable that the RFL adhesion treatment is performed by dipping in an adhesive treatment liquid composed of a solution obtained by dissolving an adhesive treatment agent such as an epoxy resin or an isocyanate resin (blocked isocyanate) in a solvent such as toluene or a decomposition liquid dispersed in water and heating the same before the RFL adhesion treatment, and the adhesive layer is provided under the RFL adhesion layer 314.

The RFL adhesive layer 314 may contain cellulose-based ultrafine fibers having a fiber diameter distribution range of 50 to 500nm, or may not contain cellulose-based ultrafine fibers, as in embodiment 4.

The rubber paste adhesive layer 315 is formed of a rubber composition containing a solid component contained in a rubber paste, and the rubber composition for forming the rubber paste adhesive layer 315 is prepared by adding a cellulose-based ultrafine fiber having a fiber diameter distribution range of 50 to 500nm to a rubber component, kneading the mixture with various rubber compounding agents, heating and pressurizing the mixture, and crosslinking the mixture with a crosslinking agent. As described above, since the rubber paste adhesive layer 315 contains the cellulose-based microfiber having a fiber diameter distribution range of 50 to 500nm, high adhesion force of the tooth portion side reinforcing fabric 312 to the toothed belt main body 310 can be obtained.

Examples of the rubber component of the rubber composition forming the rubber paste adhesive layer 315 include hydrogenated acrylonitrile rubber (H-HBR), hydrogenated acrylonitrile rubber reinforced with a metal salt of an unsaturated carboxylic acid (H-HBR), ethylene-propylene copolymer (EPR), ethylene-propylene-diene terpolymer (EPDM), ethylene-octene copolymer, ethylene-butene copolymer, and other ethylene- α -olefin elastomers, Chloroprene Rubber (CR), and chlorosulfonated polyethylene rubber (CSM). The rubber component of the rubber composition forming the toothed belt main body 310 is preferably one or a mixed rubber of two or more kinds. The rubber composition of the rubber paste adhesive layer 315 may be the same as or different from the rubber composition of the toothed belt main body 310.

The cellulose-based microfiber included in the rubber composition forming the rubber paste adhesive layer 315 has the same structure as the cellulose-based microfiber included in the toothed belt main body 310 according to embodiment 4. In the rubber paste adhesive layer 315, the cellulose-based ultrafine fibers are not oriented in a specific direction, and are randomly oriented.

The content of the cellulose-based ultrafine fibers in the rubber paste adhesive layer 315 is preferably 1 part by mass or more, more preferably 3 parts by mass or more, further preferably 5 parts by mass or more, and further preferably 30 parts by mass or less, more preferably 20 parts by mass or less, further preferably 10 parts by mass or less, per 100 parts by mass of the rubber component, from the viewpoint of high adhesiveness of the tooth-side reinforcing fabric 312 to the toothed belt body 310.

Examples of the rubber compounding agent include a reinforcing agent, a friction coefficient reducing agent, a crosslinking agent, and an antioxidant.

Examples of the carbon black as the reinforcing material include channel black, SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, N-234 and other furnace blacks, FT, MT and other thermal blacks, acetylene black and the like. Silicon dioxide can also be mentioned as a reinforcing material. The reinforcing material is preferably one or two or more thereof. The content of the reinforcing material is preferably less than the content of the reinforcing material of the rubber composition for forming the toothed belt body 310, and may be, for example, 10 to 30 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of the friction coefficient reducing material include ultrahigh molecular weight polyethylene resin powder, fluororesin powder, molybdenum, and the like. The friction coefficient reducing material is preferably one or two or more thereof. The content of the friction coefficient reducing material may be, for example, 5 to 15 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of the crosslinking agent include sulfur and an organic peroxide. The crosslinking agent may contain sulfur, an organic peroxide, or both. The amount of the crosslinking agent to be blended may be, for example, 0.3 to 5 parts by mass per 100 parts by mass of the rubber component in the case of sulfur, and 0.3 to 5 parts by mass per 100 parts by mass of the rubber component in the case of organic peroxide.

Examples of the antioxidant include amine-based antioxidants, diamine-based antioxidants, phenol-based antioxidants, and the like. The aging inhibitor is preferably one or more of these. The content of the antioxidant may be, for example, 1 to 3 parts by mass per 100 parts by mass of the rubber component.

In addition, in the rubber composition forming the rubber paste adhesive layer 315, short fibers having a fiber diameter of 10 μm or more are preferably not included, but may be included within a range that does not affect the adhesiveness of the tooth-side reinforcing cloth 312 to the toothed belt main body 310.

According to the toothed belt B of embodiment 8 configured as described above, since the rubber paste adhesive layer 315 provided between the tooth-side reinforcing cloth 312 and the toothed belt main body 310 contains the cellulose-based ultrafine fibers having the fiber diameter distribution range of 50 to 500nm, a high adhesive force of the tooth-side reinforcing cloth 312 to the toothed belt main body 310 can be obtained, and therefore, an excellent reinforcing effect can be obtained, and in particular, the tooth portion 311B can be prevented from being broken, and excellent oil resistance can be obtained. Further, since the rubber paste adhesive layer 315 contains cellulose-based ultrafine fibers having a fiber diameter distribution range of 50 to 500nm, the tooth-side surface can be made to have high abrasion resistance. As a result, high durability can be obtained.

(method of manufacturing toothed Belt B)

In the method of manufacturing the toothed belt B according to embodiment 8, in the material preparation step, when the tooth portion side reinforcing cloth 312 'is manufactured, the tooth portion side reinforcing cloth 312' is subjected to the adhesion treatment. Specifically, the tooth-side reinforcing fabric 312' is subjected to RFL adhesion treatment in which it is immersed in an RFL aqueous solution and heated, and is further subjected to rubber paste adhesion treatment in which it is immersed in rubber paste and dried, or rubber paste adhesion treatment in which it is applied to the surface of the toothed belt main body 310 side and dried. Further, it is preferable to perform a base adhesion treatment by dipping in a base adhesion treatment liquid and heating before the RFL adhesion treatment.

The substrate bonding process is the same as embodiment 7.

RFL adhesion treatment

The RFL aqueous solution is an aqueous solution obtained by mixing a rubber latex with an initial condensate of resorcinol and formaldehyde. In the case where the RFL adhesive layer 314 contains the cellulose-based microfiber, a dispersion (gel) in which the cellulose-based microfiber is dispersed in water may be contained in the RFL aqueous solution in the same manner as in embodiment 7. The liquid temperature of the RFL aqueous solution may be, for example, 20 to 30 ℃. The solid content concentration of the RFL aqueous solution is preferably 30% by mass or less.

The molar ratio of resorcinol (R) to formalin (F) is, for example, 1/1-1/2 (R/F). Examples of the rubber latex include vinylpyridine-styrene-butadiene rubber latex (Vp-St-SBR), chloroprene rubber latex (CR), and chlorosulfonated polyethylene rubber latex (CSM). The mass ratio of the solid content of the initial condensate (RF) of resorcinol and formaldehyde to the solid content of the rubber latex (L) is, for example, 1/5 to 1/20 in terms of RF/L.

Treatment of rubber paste adhesion

The rubber paste is a solution in which an uncrosslinked rubber composition containing cellulose-based ultrafine fibers for forming the rubber paste adhesive layer 315 before crosslinking is dissolved in a solvent such as toluene. A rubber paste was prepared in the following manner.

Among them, examples of the method for dispersing the cellulose-based microfine fibers in the rubber component include the following methods: a dispersion (gel) in which a cellulose-based ultrafine fiber is dispersed in water is put into a rubber component masticated by an open mill, and water is vaporized while kneading the components; a cellulose-based microfiber/rubber master batch obtained by mixing a dispersion (gel) in which cellulose-based microfiber is dispersed in water with a rubber latex and vaporizing water is put into a masticated rubber component; a step of adding a cellulose microfiber/rubber master batch obtained by mixing a dispersion obtained by dispersing hydrophobized cellulose microfiber in a solvent with a solution obtained by dissolving a rubber component in a solvent and vaporizing the solvent to a masticated rubber component; freeze-drying and pulverizing a dispersion (gel) in which cellulose-based ultrafine fibers are dispersed in water, and then adding the resultant to a masticated rubber component; and adding the hydrophobized cellulose-based ultrafine fiber to the masticated rubber component.

Then, the rubber component and the cellulose-based microfiber were kneaded together, and various rubber compounding agents were added thereto, and the resulting mixture was further kneaded to prepare an uncrosslinked rubber composition.

Then, the uncrosslinked rubber composition was put into a solvent and stirred until a uniform solution was formed, thereby preparing a rubber paste. The liquid temperature of the rubber paste may be, for example, 20 to 30 ℃.

The solid content concentration of the rubber paste is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 30% by mass or less, more preferably 20% by mass or less in the bonding treatment for impregnating the rubber paste. In the adhesion treatment for coating the rubber paste, it is preferably 10% by mass or more, more preferably 20% by mass or more, and further preferably 50% by mass or less, more preferably 40% by mass or less.

In the case of the rubber paste impregnation bonding treatment, the impregnation time in the rubber paste may be, for example, 1 to 3 seconds. The drying temperature (oven temperature) after the dipping in the rubber paste may be, for example, 50 to 100 ℃. The drying time (residence time in the furnace) may be, for example, 1 to 3 minutes. The number of times of the adhesion treatment with the rubber paste may be one or two or more. The rubber paste adhesive layer 315 is adhered to the tooth-side reinforcing cloth 312 ', but the amount of adhesion (amount of application) may be, for example, 2 to 5 mass% based on the mass of the fiber material forming the tooth-side reinforcing cloth 312'.

In the case of the rubber paste coating adhesion treatment, the drying temperature (oven temperature) after coating may be, for example, 50 to 100 ℃. The drying time (residence time in the furnace) may be, for example, 1 to 3 minutes. The number of the adhesion treatment with the rubber paste may be one or two or more. The rubber paste adhesive layer 315 is adhered to the tooth portion side reinforcing cloth 312 ', but the amount of adhesion (amount of application) is based on the mass of the fiber material forming the tooth portion side reinforcing cloth 312'. For example, the amount of the surfactant may be 2 to 5% by mass.

The other methods are the same as embodiment 4.

Examples-

(uncrosslinked rubber composition)

Rubbers 1 to 7 of the following non-crosslinked rubber compositions for forming the tooth belt main body and rubbers 8 to 14 of the non-crosslinked rubber compositions for the rubber paste adhesive layer of the tooth side reinforcing cloth were prepared. Tables 6 and 7 show various combinations.

< rubber 1 >

First, a dispersion in which powdered cellulose (product name of Japan paper making Co., Ltd.: KCflock W-GK) was dispersed in toluene was prepared, and the powdered cellulose was defibrated into cellulose microfibers by colliding the dispersions with each other using a high-pressure homogenizer to obtain a dispersion in which cellulose microfibers were dispersed in toluene. Thus, the cellulose microfiber was produced by a mechanical defibration method and was not subjected to a hydrophobization treatment.

Then, this dispersion in which the cellulose microfiber was dispersed in toluene was mixed with a solution in which H-HBR (product name of ZEON corporation, Japan: Zetpol2020) was dissolved in toluene and a plasticizer (product name of DIC corporation: W-260) was added to vaporize the toluene and the plasticizer, to prepare a cellulose microfiber/H-HBR master batch. In addition, the content of each component in the master batch was 25 mass% of cellulose-based ultrafine fibers, 25 mass% of a plasticizer, and 50 mass% of H-HBR.

Then, the H-HBR was masticated, and the master batch was put therein and kneaded. The mixing mass ratio of the H-HBR to the master batch was 98:4, and the content of the cellulose ultrafine fibers was 1 part by mass in the case where the total amount of H-HBR was 100 parts by mass.

Then, the H-HBR, the cellulose microfiber and the plasticizer were kneaded, and 40 parts by mass of FEF carbon black (SeASSO, trade name of Toshiba carbon Co.) as a reinforcing material, 1 part by mass of stearic acid (Centario sinensis, manufactured by Nippon oil Co., Ltd.) as a processing aid, 5 parts by mass of zinc oxide (two kinds of zinc oxide, manufactured by Nippon chemical industries Co., Ltd.), 24 parts by mass of a plasticizer, 5 parts by mass of liquid NBR (Nipol 1312, manufactured by Nippon ZEON Co., Ltd.) as a co-crosslinking agent, 0.5 parts by mass of sulfur (oil Sulfur, manufactured by Nippon Dry distillation industries Co., Ltd.), 2 parts by mass of a Kalan vulcanization accelerator (Nocseller TET-G, manufactured by Nippon chemical industries Co., Ltd.) and 2 parts by mass of an amine-ketone anti-aging agent (Nocseller TET-G, manufactured by Nippon chemical industries, trade name: nocrac224), and further kneading was performed to prepare an uncrosslinked rubber composition. This uncrosslinked rubber composition was used as rubber 1. Further, as for the content of the plasticizer in the rubber 1, the total amount contained in the master batch and added later was 25 parts by mass with respect to 100 parts by mass of HNBR.

< rubber 2 >

An uncrosslinked rubber composition prepared in the same manner as in rubber 1 was used as rubber 2, except that the content of the cellulose microfiber was set to 3 parts by mass with respect to 100 parts by mass of H-HBR.

< rubber 3 >

An uncrosslinked rubber composition prepared in the same manner as in rubber 1 was used as rubber 3, except that the content of the cellulose microfiber was 5 parts by mass with respect to 100 parts by mass of H-HBR.

< rubber 4 >

An uncrosslinked rubber composition prepared in the same manner as in rubber 1 was used as rubber 4, except that the content of the cellulose microfiber was set to 10 parts by mass with respect to 100 parts by mass of H-HBR.

< rubber 5 >

An uncrosslinked rubber composition prepared in the same manner as in rubber 1 was used as rubber 5, except that the content of the cellulose microfiber was set to 15 parts by mass with respect to 100 parts by mass of H-HBR.

< rubber 6 >

An uncrosslinked rubber composition prepared in the same manner as in rubber 1 was used as rubber 6, except that the content of the cellulose microfiber was set to 25 parts by mass with respect to 100 parts by mass of H-HBR.

< rubber 7 >

The H-HBR was masticated, and 40 parts by mass of FEF carbon black as a reinforcing material, 1 part by mass of stearic acid as a processing aid, 5 parts by mass of zinc oxide as a vulcanization-accelerating aid, 10 parts by mass of a plasticizer, 5 parts by mass of liquid NBR as a co-crosslinking agent, 0.5 parts by mass of sulfur as a crosslinking agent, 2 parts by mass of a thiuram-type vulcanization accelerator, and 2 parts by mass of an amine-based antioxidant were put into each of the H-HBR, relative to 100 parts by mass of the H-HBR, and kneaded to prepare an uncrosslinked rubber composition. This uncrosslinked rubber composition was used as rubber 7. Thus, the rubber 7 does not contain cellulose microfiber.

[ Table 6]

< rubber 8 >

Zinc methacrylate-reinforced H-HBR (product name of japan ZEON company: zeofort ZSC 2295) and H-HBR (product name of japan ZEON company: Zetpole 2020) were masticated in such a manner that the mixing mass ratio of the latter was 50:50, and 20 parts by mass of FEF carbon black (product name of east sea carbon company: SEAST SO) as a reinforcing material, 10 parts by mass of ultra high molecular weight polyethylene powder (product name of mitsui chemical company: mipelon xm-220) as a friction coefficient reducing material, 0.5 parts by mass of sulfur (product name of japan retort industry company: oilSulfur) as a crosslinking agent, 2 parts by mass of thiuram vulcanization accelerator (product name of intramural chemical company: nocseler TET-G) and 2 parts by mass of an amine anti-aging agent (product of intramural chemical company: nocrasac 224) were charged therein, respectively, kneading was carried out to prepare an uncrosslinked rubber composition. This uncrosslinked rubber composition was used as rubber 8. Thus, the rubber 8 does not contain cellulose microfiber.

< rubber 9 >

The zinc methacrylate-reinforced H-HBR and H-HBR are plasticated, and the master batch is added thereto and kneaded. The mixing mass ratio of the zinc methacrylate-reinforced H-HBR, the H-HBR and the master batch is 50:48:4, and the content of the cellulose ultrafine fiber is 1 part by mass when the total amount of the H-HBR is 100 parts by mass.

Then, zinc methacrylate-reinforced H-HBR, cellulose microfiber, and a plasticizer were kneaded, and 20 parts by mass of FEF black as a reinforcing material, 10 parts by mass of ultra-high molecular weight polyethylene powder, 0.5 part by mass of sulfur as a crosslinking agent, 2 parts by mass of a thiuram vulcanization accelerator, and 2 parts by mass of an amine ketone antioxidant were added to 100 parts by mass of the rubber component of zinc methacrylate-reinforced H-HBR and H-HBR, respectively, and the kneaded product was kneaded to prepare an uncrosslinked rubber composition. This uncrosslinked rubber composition was used as rubber 9.

< rubber 10 >

An uncrosslinked rubber composition was prepared as rubber 10 in the same manner as rubber 9, except that the content of the cellulose ultrafine fibers was set to 3 parts by mass with respect to 100 parts by mass of the rubber component.

< rubber 11 >

An uncrosslinked rubber composition was prepared as rubber 11 in the same manner as rubber 9, except that the content of the cellulose ultrafine fibers was set to 5 parts by mass with respect to 100 parts by mass of the rubber component.

< rubber 12 >

An uncrosslinked rubber composition was prepared as rubber 12 in the same manner as rubber 9, except that the content of the cellulose ultrafine fibers was 10 parts by mass per 100 parts by mass of the rubber component.

< rubber 13 >

An uncrosslinked rubber composition was prepared as rubber 13 in the same manner as rubber 9, except that the content of the cellulose ultrafine fibers was set to 15 parts by mass with respect to 100 parts by mass of the rubber component.

< rubber 14 >

An uncrosslinked rubber composition was prepared as rubber 14 in the same manner as rubber 9, except that the content of the cellulose ultrafine fibers was set to 25 parts by mass with respect to 100 parts by mass of the rubber component.

[ Table 7]

(toothed Belt for Experimental evaluation)

Toothed belts for experimental evaluation (pitch of teeth 8mm, width of belt 10mm) of examples 6-1 to 6-13 and comparative example 6 below were produced. The respective structures are shown in table 8.

< example 6-1 >)

In the toothed belt of example 6-1, as the uncrosslinked rubber composition forming the main body of the toothed belt, rubber 1 containing cellulose ultrafine fibers was used.

As the tooth-side reinforcing fabric, a woven fabric was used in which a covering yarn, which was made of a polyurethane yarn wound with an aramid fiber (product name of tei corporation: Technora) and provided with stretchability, was used as a weft and a nylon twisted yarn was used as a warp. The woven fabric of the tooth-side reinforcing fabric is subjected to a primer adhesion treatment in which the woven fabric is immersed in an epoxy resin solution and then heated, and an RFL adhesion treatment in which the woven fabric is immersed in an RFL aqueous solution and then heated. Further, the rubber paste impregnation bonding treatment of impregnating the woven fabric of the tooth-side reinforcing fabric subjected to the RFL bonding treatment with the rubber paste and drying was repeated twice. As the rubber paste, a rubber paste having a solid content concentration of 10 mass% was used in which rubber 8 containing no cellulose microfiber was dissolved in a toluene solvent. The liquid temperature of the rubber paste was 25 ℃. The dipping time of the rubber paste was 5 seconds. The drying temperature after the rubber paste impregnation was 100 ℃ and the drying time was 40 seconds.

As the core wire, a glass fiber core wire is used.

< example 6-2 >

The toothed belt of example 6-2 was produced in the same manner as in example 6-1, except that the rubber 2 containing the cellulose ultrafine fibers was used as the uncrosslinked rubber composition for forming the toothed belt main body.

< example 6-3 >

The toothed belt of example 6-3 was produced in the same manner as in example 6-1, except that the rubber 3 containing the cellulose ultrafine fibers was used as the uncrosslinked rubber composition for forming the toothed belt main body.

< example 6-4 >

The toothed belt of example 6-4 was produced in the same manner as in example 6-1, except that the rubber 4 containing the cellulose ultrafine fibers was used as the uncrosslinked rubber composition for forming the toothed belt main body.

< example 6-5 >

The toothed belts of examples 6 to 5 were produced in the same manner as in examples 6 to 4, except that the rubber paste containing the cellulose microfiber rubber 9 was used in the rubber paste impregnation and adhesion treatment of the tooth-side reinforcing fabric.

< example 6-6 >

The toothed belts of examples 6 to 6 were produced in the same manner as in examples 6 to 4, except that the rubber paste containing the cellulose microfiber rubber 10 was used in the rubber paste impregnation and adhesion treatment of the tooth-side reinforcing fabric.

< example 6-7 >

The toothed belts of examples 6 to 7 were produced in the same manner as in examples 6 to 4, except that the rubber paste containing the cellulose microfiber rubber 11 was used in the rubber paste impregnation and adhesion treatment of the tooth-side reinforcing fabric.

< example 6-8 >

Toothed belts of examples 6 to 8 were produced in the same manner as in examples 6 to 4, except that a rubber paste containing a rubber 12 of cellulose microfiber was used for the rubber paste impregnation bonding treatment of the tooth-side reinforcing fabric.

< example 6-9 >

Toothed belts of examples 6 to 9 were produced in the same manner as in examples 6 to 4, except that a rubber paste containing a rubber 13 of cellulose microfiber was used in the rubber paste impregnation bonding treatment of the tooth-side reinforcing fabric.

< example 6-10 >

Toothed belts of examples 6 to 10 were produced in the same manner as in examples 6 to 4, except that a rubber paste containing a rubber 14 of cellulose microfiber was used in the rubber paste impregnation bonding treatment of the tooth-side reinforcing fabric.

< example 6-11 >

The toothed belts of examples 6 to 11 were produced in the same manner as in example 6-1, except that the rubber 5 containing the cellulose ultrafine fibers was used as the uncrosslinked rubber composition for forming the toothed belt main body.

< example 6-12 >

The toothed belts of examples 6 to 12 were produced in the same manner as in example 6-1, except that the rubber 6 containing the cellulose ultrafine fibers was used as the uncrosslinked rubber composition for forming the toothed belt main body.

< example 6-13 >

A toothed belt of example 6-13 was produced in the same manner as in example 6-1, except that the rubber 7 containing the cellulose ultrafine fibers was used as the uncrosslinked rubber composition forming the main body of the toothed belt, and that the rubber 12 containing the cellulose ultrafine fibers was used in the rubber paste impregnation bonding treatment of the tooth-side reinforcing fabric.

< comparative example 6 >

A toothed belt of comparative example 6 was produced in the same manner as in example 6-1, except that the rubber 7 containing no cellulose ultrafine fibers was used as the uncrosslinked rubber composition forming the toothed belt body, and the rubber 8 containing no cellulose ultrafine fibers was used in the rubber paste-impregnated bonding treatment of the tooth-side reinforcing fabric.

[ Table 8]

(test evaluation method)

< average fiber diameter and fiber diameter distribution of cellulose ultrafine fibers >

Samples of rubber compositions of crosslinked rubbers 1 to 6 and rubbers 9 to 14 were collected from the main body of the toothed belt and the rubber paste adhesive layer of the toothed belts of examples 6-1 to 6-13, and the samples of these rubber compositions were freeze-pulverized, and then the cross sections thereof were observed by a Scanning Electron Microscope (SEM), and the fiber diameters were measured by selecting 50 fibers arbitrarily, and the average of the fiber diameters was determined. In addition, the maximum value and the minimum value of the fiber diameter among 50 cellulose microfibers were obtained.

< Belt running test >

Fig. 32 shows a pulley design of the belt running test machine 330.

The belt running test machine 330 includes a driving pulley 331, a driven pulley 332, and a guide pulley 333. The drive pulley 331 is provided with 21 tooth engagement grooves at the pulley periphery. The driven pulley 332 is provided with 42 tooth engagement slots at the pulley periphery. The guide roller 333 forms a pulley peripheral edge into a flat surface by pressing the belt back surface. The driving pulley 331, the driven pulley 332, and the guide pulley 333 are all made of carbon steel (S45C).

The tooth chipping resistance and wear resistance of the toothed belts B of examples 6-1 to 6-13 and comparative example 6 were evaluated by the following methods using the belt running test machine 330.

Evaluation of tooth fracture resistance-

First, the mass of the toothed belt B is measured. Then, the toothed belt B is wound around the belt running tester 330, and the driven pulley 332 receives a load rearward, thereby applying a tension of 216N to the toothed belt B. Then, the driving pulley 331 was rotated at 3000rpm so that the tension applied to the toothed belt B was 550N, and the belt was operated, and the operating time until the teeth were broken was defined as the tooth durability life. The tape running tests of examples 6-1 to 6-13 and comparative example 6 were performed at room temperature, and the tape running tests of examples 6-1 to 6-4, 6-11, 6-12 and comparative example 6 were performed at 80 ℃.

Evaluation of abrasion resistance

The toothed belt B was subjected to a belt run for 300 hours under the same conditions as the above-described wear resistance measurement. After the belt was operated, the mass of the toothed belt B was measured again, and the mass difference before and after the operation was calculated as the wear mass.

< oil resistance test >

The toothed belts of examples 6-1 to 6-13 and comparative example 6 were measured for their mass and then immersed in fresh engine oil at 140 ℃ for 168 hours. Then, the adhered oil was sufficiently removed by an air gun, and the mass was measured again. The mass change rate (in%) before and after impregnation was calculated.

(test evaluation results)

The results of the experiment are shown in tables 9 and 10. In addition, the content of the cellulose ultrafine fibers means a mass part with respect to 100 mass parts of the rubber component, unless otherwise specified below.

[ Table 9]

[ Table 10]

As is clear from Table 10, the distribution of the fiber diameters of the cellulose ultrafine fibers contained in the rubber compositions of the crosslinked rubbers 1 to 6 and the rubbers 9 to 14 is wide.

< Belt running test >

Tooth defect resistance (room temperature) -

In comparative example 6 in which neither the toothed belt body nor the rubber paste adhesive layer contained the cellulose microfiber, the tooth durability life at room temperature was 384 hours.

On the other hand, in examples 6-1 to 6-4 and examples 6-11 to 6-12, in which the cellulose ultrafine fibers were contained only in the toothed belt main body in amounts of 0 part by mass, 1 part by mass, 3 parts by mass, 5 parts by mass, 10 parts by mass, 15 parts by mass, and 25 parts by mass, respectively, the tooth durability lives at room temperature were 528 hours, 696 hours, 792 hours, 864 hours, 936 hours, and 1056 hours, respectively. That is, it is understood that the durability life of the tooth portion is increased as the content of the cellulose microfiber is increased within the range of the present embodiment.

Further, it was found that in examples 6-4 to 6-10 in which the content of the cellulose microfine fibers in the toothed belt main body was the same as 10 parts by mass, the tooth durability life was substantially increased as the content of the cellulose microfine fibers in the rubber paste adhesive layer was increased. Specifically, the contents of the cellulose ultrafine fibers in the rubber paste adhesive layers of examples 6-4 to 6-10 were 0 parts by mass, 1 part by mass, 3 parts by mass, 5 parts by mass, 10 parts by mass, 15 parts by mass, and 25 parts by mass, respectively, and the tooth durability lives at room temperature were 864 hours, 912 hours, 960 hours, 1032 hours, 1080 hours, 1128 hours, and 1128 hours, respectively. Further, in examples 6 to 9 and 6 to 10, since the durability lives of the teeth were the same, it is considered that the effect of improving the durability of the teeth could be saturated when the content of the cellulose microfiber was 15 parts by mass or more.

In examples 6 to 13 in which 10 parts by mass of the cellulose microfiber was contained only in the rubber paste adhesive layer, the tooth durability life was 456 hours, and slightly longer than 384 hours in comparative example 6. However, in the case of examples 6 to 8 in which the content of the cellulose microfine fibers in the toothed belt main body was 10 parts by mass, the content of the cellulose microfine fibers in the rubber paste adhesive layer was the same as in examples 6 to 13, but the tooth durability life was 1080 hours, which was significantly superior to that of examples 6 to 13.

From this, it is found that the durability life of the tooth portion can be improved in the case where the cellulose microfiber is contained in either the toothed belt main body or the rubber paste adhesive layer, but the effect is remarkable in the case where the cellulose microfiber is contained in the toothed belt main body.

Tooth defect resistance (80 ℃) -

In comparative example 6 in which neither the toothed belt body nor the rubber paste adhesive layer contained the cellulose microfiber, the tooth durability life at 80 ℃ was 240 hours.

On the other hand, in examples 6-1 to 6-4 and examples 6-11 to 6-12, in which the cellulose microfiber was contained only in the toothed belt main body in an amount of 0 part by mass, 1 part by mass, 3 parts by mass, 5 parts by mass, 10 parts by mass, 15 parts by mass, and 25 parts by mass, respectively, the tooth durability lives at 80 ℃ were 432 hours, 624 hours, 744 hours, 792 hours, 888 hours, and 9126 hours, respectively. That is, it is understood that, in the range of the present example, as the content of the cellulose microfiber increases, the tooth durability life at high temperature becomes longer.

In addition, the durability life of the teeth at high temperature (80 ℃) is shorter than that at room temperature. However, the degree of deterioration can be reduced by containing the cellulose microfiber. That is, in comparative example 6, the durability life of the teeth at room temperature was 384 hours, and the durability life of the teeth at 80 ℃ was 240 hours, which was about 38% deterioration. On the other hand, in example 6-1 in which 1 part by mass of the cellulose microfiber was contained in the toothed belt main body, the tooth endurance life at room temperature was 528 hours, and the tooth endurance life at 80 ℃ was 432 hours, which was about 18% deterioration. In examples 6-2, 6-3, 6-4, 6-11, and 6-12, the degree of deterioration was about 10%, 6%, 8%, 5%, and 14% in this order, and it was found that the degree of deterioration was much reduced as compared with the case where the cellulose microfiber was not contained.

As described above, the reason why the durability life of the tooth portion at high temperature can be reduced by containing the cellulose microfiber is that the linear expansion coefficient can be reduced. That is, the linear expansion coefficient of the toothed belt can be reduced by containing the cellulose ultrafine fibers. If the linear expansion coefficient is reduced, the expansion of the tooth portion at high temperature is suppressed. As a result, the meshing accuracy between the teeth and the pulley can be maintained at high temperatures, and an increase in the load on the teeth due to a temperature increase can be suppressed.

Abrasion resistance-

In comparative example 6 in which neither the toothed belt body nor the rubber paste adhesive layer contained the cellulose ultrafine fibers, the abrasion mass was 4.1 g. In examples 6-1 to 6-4 and 6-11 to 6-12 in which the fibrous ultrafine fibers were contained only in the toothed belt main body, the wear mass was 3.9g to 4.3 g. From this, it is found that the wear resistance cannot be significantly improved by only including the cellulose microfiber in the toothed belt main body.

On the other hand, in examples 6-4 to 6-10 in which the content of the cellulose microfine fibers in the toothed belt main body was 10 parts by mass, the content of the cellulose microfine fibers in the rubber paste adhesive layer was 0 part by mass, 1 part by mass, 3 parts by mass, 5 parts by mass, 10 parts by mass, 15 parts by mass, and 25 parts by mass, respectively, and the abrasion mass was 4.2g, 3.3g, 2.5g, 2.1g, 1.8g, 1.4g, and 1.3g in this order. That is, as the content of the cellulose microfiber of the rubber paste adhesive layer increases, the abrasion quality decreases. Among them, if the wear mass is 3.5g or less, it is considered that the improvement is excellent over the conventional state.

In examples 6 to 13 in which the toothed belt body contained no cellulose ultrafine fibers, the rubber paste adhesive layer contained 10 parts by mass of cellulose ultrafine fibers, and the abrasion mass was 2.0g, it was found that the abrasion resistance was significantly improved.

From this, it is found that the effect of improving the wear resistance can be obtained by including the cellulose ultrafine fibers in the rubber paste adhesive layer of the tooth portion side reinforcing fabric.

< oil resistance test >

In comparative example 6 in which neither the toothed belt main body nor the rubber paste adhesive layer contained the cellulose ultrafine fibers, the amount of mass change before and after oil swelling, which is an evaluation index of oil resistance, was 4.4%.

On the other hand, in examples 6-1 to 6-4 and examples 6-11 to 6-12, in which the cellulose microfiber was contained only in the toothed belt main body in an amount of 0 part by mass, 1 part by mass, 3 parts by mass, 5 parts by mass, 10 parts by mass, 15 parts by mass, and 25 parts by mass, respectively, the amounts of change in mass were 3.9%, 3.7%, 3.1%, 2.8%, 1.9%, and 1.5%, respectively. That is, it is understood that the amount of change in mass becomes smaller and the oil resistance is improved as the content of the cellulose microfiber is increased within the range of the present example.

In examples 6-4 to 6-10 in which the content of the cellulose microfine fibers in the toothed belt main body was 10 parts by mass, the content of the cellulose microfine fibers in the rubber paste adhesive layer was 0 part by mass, 1 part by mass, 3 parts by mass, 5 parts by mass, 10 parts by mass, 15 parts by mass, and 25 parts by mass, and the amount of change in mass was 2.8%, 2.7%, 2.6%, 2.3%, 2.2%, and 2.1%, respectively. That is, it is found that as the content of the cellulose microfiber in the rubber paste adhesive layer increases, the mass change rate decreases and the oil resistance improves.

In examples 6 to 13 in which 10 parts by mass of the cellulose ultrafine fibers were contained only in the rubber paste adhesive layer, the mass change rate was 4.3%, and was slightly suppressed from 4.4% in comparative example 6. In examples 6 to 8 in which the content of the cellulose microfine fibers in the toothed belt body was 10 parts by mass, the content of the cellulose microfine fibers in the rubber paste adhesive layer was the same as in examples 6 to 13, but the mass change rate was 2.3%.

It is understood from this that the oil resistance can be improved by including the cellulose ultrafine fibers in the toothed belt main body, and the oil resistance can be improved even when the cellulose ultrafine fibers are included only in the rubber paste adhesive layer of the tooth portion side reinforcing cloth, although the effect is small. Further, it was found that the oil resistance can be significantly improved when both the toothed belt main body and the rubber paste adhesive layer contain cellulose ultrafine fibers.

Industrial applicability

The present invention is useful for a belt for power transmission.

Claims

1. A transmission belt that is wound around a pulley having a tooth engaging groove and transmits power, characterized in that,

the transmission belt is a toothed belt, and is provided with a toothed belt main body and a tooth side reinforcing cloth,

the toothed belt main body has a flat belt-like base portion and a plurality of teeth portions integrally provided at one side surface of the base portion at intervals in a belt length direction,

the tooth-side reinforcing cloth is attached to the toothed belt main body so as to cover a side surface of the tooth portion with an adhesive layer containing a rubber component,

the tooth part meshing groove is meshed with the tooth part,

the base, the tooth, and the adhesive layer are formed of a rubber composition containing cellulose-based ultrafine fibers and short fibers having an average diameter of 1 [ mu ] m or more, and the distribution range of the fiber diameters of the cellulose-based ultrafine fibers is 83 to 390 nm.

2. The belt of claim 1,

carbon black is not blended in the rubber composition.

3. The belt of claim 1,

the cellulose-based microfiber is manufactured by a mechanical defibration method.

4. The belt of claim 1,

the cellulose-based microfiber is produced by a chemical defibration method.

5. The belt of claim 1,

the content of the cellulose-based ultrafine fiber is 1 to 25 parts by mass per 100 parts by mass of the rubber component of the rubber composition.

6. The belt of claim 1,

the rubber composition contains short fibers having a fiber diameter of 10 [ mu ] m or more.

7. The belt of claim 6,

the content of the short fiber with respect to 100 parts by mass of the rubber component of the rubber composition is greater than the content of the cellulose-based microfine fiber with respect to 100 parts by mass of the rubber component of the rubber composition.

8. The belt of claim 1,

the content of the cellulose-based ultrafine fiber in the rubber composition is 1 to 30 parts by mass per 100 parts by mass of the rubber component.

9. The belt of claim 1,

the rubber component of the rubber composition forming the toothed belt body contains a hydrogenated acrylonitrile rubber.

10. The belt of claim 1,

the rubber component contained in the adhesive layer contains a hydrogenated acrylonitrile rubber and a hydrogenated acrylonitrile rubber reinforced with a metal salt of unsaturated carboxylic acid.

11. A transmission belt that is wound around a pulley having a tooth engaging groove and transmits power, characterized in that,

the tooth part meshing groove is meshed with the tooth part,

the base, the tooth, and the adhesive layer are formed of a rubber composition containing cellulose-based ultrafine fibers and short fibers having an average diameter of 1 μm or more, and the distribution range of the fiber diameters of the cellulose-based ultrafine fibers is 20 to 500 nm.