CN107532681A - Transmission belt - Google Patents

Abstract

The present invention provides transmission belt that is a kind of while meeting required multiple characteristics.Transmission belt (B) is so as to the transmission belt of passing power on belt wheel.The transmission belt has the layer by being formed containing cellulose family superfine fibre and average diameter for the rubber composition of more than 1 μm of chopped fiber (16).

Description

Transmission belt

technical field

The present invention relates to transmission belts.

Background technique

Short fibers are blended into 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-belt is made of a rubber composition containing carbon black and short fibers.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2014-167347

Transmission belts are required to have various characteristics such as wear resistance, coefficient of friction, and suppression of adhesive wear. When carbon black and short fibers are added to the rubber composition constituting the belt for reinforcement, if certain properties are satisfied by adjusting the compounding amount, other properties tend to be deteriorated.

Contents of the invention

Therefore, an object of the present invention is to provide a power transmission belt capable of simultaneously satisfying various required properties.

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

According to the present invention, since it has a layer composed of a rubber composition containing cellulose-based microfibers and other short fibers, it is possible to make a power transmission belt satisfy various required properties at the same time.

Description of drawings

FIG. 1 is a perspective view schematically showing a V-ribbed belt as an example of Embodiments 1 and 2. FIG.

2 is a cross-sectional view of a main part of a V-ribbed belt according to Embodiments 1 and 2. FIG.

FIG. 3 is a first explanatory diagram showing a method of manufacturing the V-ribbed belt according to Embodiments 1 and 2. FIG.

FIG. 4 is a second explanatory diagram showing a method of manufacturing the V-ribbed belt according to Embodiments 1 and 2. FIG.

FIG. 5 is a third explanatory diagram showing a method of manufacturing the V-ribbed belt according to Embodiments 1 and 2. FIG.

FIG. 6 is a fourth explanatory diagram showing a method of manufacturing the V-ribbed belt according to Embodiments 1 and 2. FIG.

FIG. 7 is a fifth explanatory diagram showing a method of manufacturing the V-ribbed belt according to Embodiments 1 and 2. FIG.

FIG. 8 is a sixth explanatory diagram showing a method of manufacturing the V-ribbed belt according to Embodiments 1 and 2. FIG.

Fig. 9 is a diagram showing a pulley design of a running test machine for measuring crack life.

Fig. 10 is a drawing showing a pulley design of a high tension belt running tester.

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

Fig. 12 is a diagram showing a pulley design of an automotive accessory drive belt transmission using the V-ribbed belt according to the embodiment.

FIG. 13 is a perspective view schematically showing a flat belt as an example of Embodiment 3. FIG.

Fig. 14 is a first explanatory diagram showing a method of manufacturing the flat belt according to the third embodiment.

FIG. 15 is a second explanatory diagram showing a method of manufacturing the flat belt according to Embodiment 3. FIG.

FIG. 16 is a third explanatory diagram showing a method of manufacturing the flat belt according to Embodiment 3. FIG.

Fig. 17 is a diagram showing the structure of a friction coefficient measuring device.

Fig. 18 is a diagram showing a pulley design of a belt running tester used for evaluating wear resistance.

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

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

Fig. 21 is a diagram showing a pulley design of a belt running tester for evaluating wear resistance.

FIG. 22 is a perspective view schematically showing a toothed belt example of Embodiment 4. FIG.

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

FIG. 24 is a first explanatory diagram of a method of manufacturing the toothed belt according to Embodiment 4. FIG.

FIG. 25 is a second explanatory diagram of a method of manufacturing the toothed belt according to Embodiment 4. FIG.

FIG. 26 is a third explanatory diagram of a method of manufacturing the toothed belt according to Embodiment 4. FIG.

FIG. 27 is a first explanatory diagram of a method of manufacturing the toothed belt according to Embodiment 5. FIG.

Fig. 28 is a second explanatory diagram of a method of manufacturing the toothed belt according to the fifth embodiment.

Fig. 29 is a third explanatory diagram of a method of manufacturing the toothed belt according to the fifth embodiment.

Fig. 30 is a cross-sectional view showing the interface structure between the tooth portion side reinforcing fabric and the toothed belt main body in Embodiment 7.

Fig. 31 is a cross-sectional view showing the interface structure between the tooth portion side reinforcing fabric and the toothed belt main body in Embodiment 8.

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

Symbol Description

10 V-belt body

11 Compression rubber layer

12 Adhesive rubber layer

13 Back rubber layer

16 short fibers

120 flat belt body

121 Inner rubber layer

122 adhesive rubber layer

123 Outer rubber layer

126 staple fiber

310 toothed belt body

311a base

311b teeth

312 core wire

313 Tooth side reinforcement cloth

314 RFL adhesive layer

315 rubber paste adhesive layer

detailed description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]

(ribbed belt B)

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

The V-ribbed belt B according to Embodiment 1 includes a V-ribbed belt main body 10 made of rubber. An adhesive rubber layer 12 in the middle and a back rubber layer 13 on the outer peripheral side of the belt. A core wire 14 is embedded in a middle portion in the thickness direction of the adhesive rubber layer 12 of the V-ribbed belt main body 10 so as to form a helix having a pitch in the belt width direction. In addition, instead of the back rubber layer 13 , a back reinforcement cloth may be provided, and the V-belt main body 10 may be configured 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 protrusion extending in the belt length direction and has a substantially inverted triangular cross-section, and are arranged in a row along the belt length direction. For each V-shaped rib 16, for example, the rib height is 2.0 to 3.0 mm, and the width between base ends is 1.0 to 3.6 mm. The number of 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 with a horizontally rectangular cross section, and its thickness is, for example, 1.0 to 2.5 mm. The back rubber layer 13 is also formed in a strip shape with a horizontally rectangular cross section, and has a thickness of, for example, 0.4 to 0.8 mm. From the viewpoint of suppressing the generation of sound during back driving, it is preferable to provide a weave pattern on the surface of the back rubber layer 13 .

The compression rubber layer 11, the adhesive rubber layer 12, and the back rubber layer 13 are formed from a rubber composition obtained by heating and kneading an uncrosslinked rubber composition in which various rubber compounding ingredients are mixed and kneaded. It is made by pressing and cross-linking with a cross-linking agent. The rubber compositions forming the compression rubber layer 11, the adhesive rubber layer 12, and the back rubber layer 13 may be the same or different.

As 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, for example, ethylene-propylene copolymer (EPR), ethylene-propylene-diene terpolymer (EPDM), ethylene-octene copolymer, ethylene-butene copolymer and other ethylene-α-olefin elastomers, neoprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), hydrogenated acrylonitrile rubber (H- HBR) etc. The rubber component is preferably one of them or a mixture of two or more rubbers. Preferably, the rubber components of the rubber compositions used to form the compression rubber layer 11, the adhesive rubber layer 12, and the back rubber layer 13 are the same.

At least one of the rubber compositions forming the compression rubber layer 11, the adhesive rubber layer 12, and the back rubber layer 13 contains cellulose-based ultrafine fibers whose fiber diameter distribution range includes 50 to 500 nm. It is preferable that all rubber compositions for forming the compression rubber layer 11, the adhesive rubber layer 12, and the back rubber layer 13 contain cellulose-based microfibers, but it is more preferable to form at least the compression rubber layer constituting the pulley contact portion. The rubber composition of No. 11 contains cellulose-based microfibers.

Cellulosic ultrafine fibers are fiber materials derived from cellulose ultrafine fibers composed of a skeleton component of plant cell walls obtained by finely dismantling plant fibers. Examples of raw material plants for cellulose-based ultrafine fibers include wood, bamboo, rice (straw), potatoes, sugar cane (bagasse), aquatic plants, 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 high reinforcing effect was found.

The cellulose ultrafine fiber may be cellulose ultrafine fiber itself, or may be hydrophobized cellulose ultrafine fiber after hydrophobization treatment. In addition, as the cellulose-based ultrafine fibers, cellulose ultrafine fibers and hydrophobized cellulose ultrafine fibers may be used together. From the standpoint of dispersibility, the cellulose-based ultrafine fibers preferably include hydrophobized cellulose ultrafine fibers. Examples of the hydrophobized cellulose ultrafine fibers include cellulose ultrafine fibers in which a part or all of the hydroxyl groups of cellulose are substituted with hydrophobic groups, and cellulose ultrafine fibers subjected to a hydrophobizing surface treatment using a surface treatment agent.

As hydrophobization for obtaining cellulose microfibers in which a part or all of the hydroxyl groups of cellulose are replaced with hydrophobic groups, for example, esterification (acylation) (alkyl esterification, complex esterification, β- Keto esterification, etc.), alkylation, tosylation, epoxidation, arylation, etc. Among them, esterification is preferable. Specifically, esterified hydrophobized cellulose superfine fibers can be obtained by passing part or all of the hydroxyl groups of cellulose through carboxylic acids such as acetic acid, anhydrous acetic acid, propionic acid, butyric acid, or their halides (especially chlorides). Acylated cellulose microfiber. As a surface treatment agent for obtaining the cellulose ultrafine fiber which surface-treated to hydrophobize using a surface treatment agent, a silane coupling agent etc. are mentioned, for example.

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

The average fiber diameter of the cellulose-based ultrafine fibers is preferably not less than 3 nm and not more than 200 nm, more preferably not less than 3 nm and not more than 100 nm.

After freezing and pulverizing a sample of the rubber composition with a main body, observe its cross-section using a transmission electron microscope (TEM), and randomly select 50 cellulose-based ultrafine fibers to measure the fiber diameter, and obtain the cellulose-based fiber diameter based on the measurement results. Fiber diameter distribution of microfibers. In addition, the average of the fiber diameters of the 50 arbitrarily selected cellulose-based ultrafine fibers was determined as the average fiber diameter of the cellulose-based ultrafine fibers.

Cellulosic microfibers may be high-aspect-ratio cellulose microfibers produced by a mechanical defibration method, or may be cellulose microfibers produced by a chemical defibration method. Among them, it is preferable to manufacture by a chemical defibrating method. In addition, as the cellulose-based ultrafine fibers, cellulose-based ultrafine fibers produced by a mechanical defibrating method and a chemical defibrating method may be used together. Examples of the defibrating apparatus used in the mechanical defibrating method include kneaders such as twin-screw kneaders, high-pressure homogenizers, grinders, sand mills, and the like. As the treatment used in the chemical defibrating method, for example, acid hydrolysis treatment and the like can be cited.

For the content of the cellulose-based microfibers in the rubber composition that constitutes the compression rubber layer 11, the adhesive rubber layer 12 and/or the back rubber layer 13, from the aspects that can satisfy the various characteristics of the transmission belt respectively, relative to 100 mass Parts of the rubber component are preferably 1 part by mass or more, more preferably 5 parts by mass or more, further preferably 10 parts by mass or more, and preferably 30 parts by mass or less, more preferably 25 parts by mass or less, further preferably 20 parts by mass or less.

In addition, examples of rubber compounding agents include reinforcing materials, oils, processing aids, vulcanization acceleration aids, crosslinking agents, auxiliary crosslinking agents, vulcanization accelerators, and the like.

As a reinforcing material, among short fibers used other than cellulose microfibers, for example, 6-nylon fibers, 6,6-nylon fibers, 4,6-nylon fibers, polyester fibers (PET), polyester fibers, etc. Ethylene naphthalate (PEN) fibers, para-aramid fibers, meta-aramid fibers, polyester fibers, etc. may contain only one type or may contain multiple types. For example, short fibers can be produced by cutting long fibers that have been subjected to a bonding treatment of immersion in an RFL aqueous solution or the like and then heated to a predetermined length.

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 preferably 100 μm or less, more preferably 70 μm or less, and still more preferably 50 μm or less.

In addition, the blending amount of 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, based on 100 parts by mass of the rubber component of the rubber composition.

As a reinforcing material, in carbon black, for example, 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 carbon black, acetylene carbon black, etc.

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

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

Examples of the vulcanization accelerator include metal oxides such as zinc oxide (zinc white) and magnesium oxide, metal carbonates, fatty acids and derivatives thereof. The vulcanization accelerators are preferably one or more of them. The content of the vulcanization accelerator may be, for example, 5 to 15 parts by mass relative to 100 parts by mass of the rubber component of the rubber composition.

Examples of the crosslinking agent include sulfur and organic peroxides. As a crosslinking agent, sulfur may be added, an organic peroxide may be added, or both may be used in combination. The compounding amount of the crosslinking agent may be, for example, 0.5 to 4.0 parts by mass for 100 parts by mass of the rubber component of the rubber composition in the case of sulfur, or 0.5 to 4.0 parts by mass for 100 parts by mass of organic peroxides. The rubber component of the rubber composition can be, for example, 0.5 to 8.0 parts by mass.

Examples of organic peroxides include dialkyl peroxides such as dicumyl peroxide, peroxyesters such as tert-butyl peroxyacetate, and ketone peroxides such as dicyclohexanone peroxide. Wait. One type of organic peroxide may be blended, or a plurality of types may be blended.

Examples of the auxiliary crosslinking agent include maleimides, TAIC, 1,2-polybutadiene, oximes, guanidine, and trimethylolpropane trimethacrylate. Auxiliary crosslinking agents are preferably one or more than two of them. The content of the auxiliary crosslinking agent may be, for example, 0.5 to 15 parts by mass relative to 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 obtained by heating and kneading an uncrosslinked rubber composition in which various rubber compounding ingredients are mixed with the rubber component. It is made by pressing and cross-linking with a cross-linking agent. Examples of the rubber component used in the rubber composition constituting the adhesive rubber layer 12 and the back rubber layer 13 include the same rubber components as those in the compression rubber layer 11 , and may be the same rubber components. Examples of the rubber compounding agent include reinforcing materials, oils, processing aids, vulcanization accelerators, crosslinking agents, auxiliary crosslinking agents, vulcanization accelerators, etc., similarly to the compression rubber layer 11 . In addition, the rubber composition for constituting the adhesive rubber layer 12 and the back rubber layer 13 may contain cellulose-based microfibers and short fibers similarly to the compression rubber layer 11 .

The core is composed of polyethylene terephthalate (PET) fiber, polyethylene naphthalate (PEN) fiber, para-aramid fiber, vinylon fiber, etc. twisted yarn, braided rope, etc. Line 14. The core wire 14 is subjected to an adhesion treatment of immersion in an RFL aqueous solution and heating and/or an adhesion treatment of immersion in a rubber paste and drying in order to achieve adhesion to the V-belt main body 10 before molding. In addition, the core wire 14 may be dipped in an adhesive solution composed of a solution such as epoxy resin, polyisocyanate resin, etc., and then heated if necessary, before the bonding treatment with the RFL aqueous solution and/or rubber paste. deal with. The diameter of the core wire 14 may be, for example, 0.5-2.5 mm, and the dimension between the centers of adjacent core wires 14 in the cross section may be, for example, 0.05-0.20 mm.

(Manufacturing method of V-belt B)

Based on FIGS. 3-8, the manufacturing method of the V-ribbed belt B which concerns on Embodiment 1 is demonstrated.

3 and 4 show a belt molding die 30 for manufacturing the V-ribbed belt B according to the first embodiment.

The belt molding die 30 includes a cylindrical inner die 31 and an outer die 32 that are concentrically arranged.

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 mold 32 constitutes a molding surface, and V-shaped rib forming grooves 33 having the same shape as the V-shaped rib 16 are provided at a constant pitch in the axial direction on the inner peripheral surface of the outer mold 32 . The outer mold 32 is provided with a temperature adjustment mechanism that circulates a heat medium such as water vapor and a cold medium such as water to adjust the temperature. In addition, a pressurizing member for pressurizing and expanding the inner mold 31 from the inside is provided.

The method of 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 compression rubber layer, adhesive rubber layer and back rubber layer-

The non-crosslinked rubber sheets 11', 12', 13' used for the compression rubber layer, the adhesive rubber layer, and the back rubber layer were prepared to contain cellulose-based microfibers in the following manner.

First, cellulose-based microfibers are put into the masticated rubber component, kneaded, and dispersed.

Among them, as a method for dispersing cellulose-based ultrafine fibers as a rubber component, for example, the following method can be cited: a dispersion (gel) obtained by dispersing cellulose-based ultrafine fibers in water is put into a plasticizer by an open mixer. In the rubber component, the moisture is vaporized while kneading them; the cellulose microfiber obtained by mixing the dispersion (gel) obtained by dispersing the cellulose ultrafine fiber in water with the rubber latex and vaporizing the water /The masterbatch of rubber is put into the rubber component of mastication; the dispersion obtained by dispersing the cellulose-based ultrafine fiber in the solvent and the solution in which the rubber component is dissolved in the solvent are mixed and the solvent is vaporized to obtain the cellulose-based ultra-fine fiber A fine fiber/rubber masterbatch is added to the masticated rubber component; a pulverized product obtained by freeze-drying a dispersion (gel) obtained by dispersing cellulose-based ultrafine fibers in water is added to the masticated rubber component; and Add hydrophobized cellulose microfibers to the masticated rubber component.

Then, various rubber compounding ingredients were put in while kneading the rubber component and the cellulose-based microfibers, and kneading was continued to prepare an uncrosslinked rubber composition.

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

In addition, various rubber compounding agents can be added to the rubber component, kneaded using a kneader such as a kneader or a Banbury mixer, and the resulting uncrosslinked rubber composition can be formed into a sheet by calendering or the like, In this way, a material that does not contain cellulose-based microfibers is produced.

-core wire 14'-

Bonding treatment is performed on the core wire 14'. Specifically, the core wire 13' is subjected to RFL bonding treatment in which the core wire 13' is dipped in an RFL aqueous solution and heated. In addition, it is preferable to perform the base bonding treatment of immersing in the base bonding treatment liquid and heating before performing the RFL bonding treatment. In addition, before performing the RFL bonding treatment, a rubber paste bonding process of dipping in a rubber paste and drying may be performed.

<Molding process>

As shown in FIG. 5, a rubber sleeve 35 is covered on a cylinder 34 with a smooth surface, and an uncrosslinked rubber sheet 13' for the back rubber layer and an uncrosslinked rubber sheet for the adhesive rubber layer are sequentially stacked and wound on its outer periphery. A cross-linked rubber sheet 12' on which the core wire 14' is spirally wound with respect to the cylindrical inner mold 31, and then an uncross-linked rubber sheet 12' for bonding the rubber layer is sequentially wound thereon And an uncrosslinked rubber sheet 11' for compressing the rubber layer. At this time, the laminated molded body B' is formed on the rubber sleeve 35. As shown in FIG.

<Crosslinking process>

Remove the rubber sleeve 35 provided with the laminated molded body B' from the cylinder 34, as shown in FIG. , the inner mold 31 is positioned in the rubber sleeve 35 provided on the outer mold 32 for sealing.

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 it. At this time, the inner mold 31 expands, and the uncrosslinked rubber sheets 11', 12', 13' of the laminated molded body B' are compressed into the molding surface of the outer mold 32, and their crosslinking is carried out, and the core wire 14' composite integration, and finally as shown in Figure 8, a cylindrical belt plate S is formed. In addition, the forming temperature of the strip S may be, for example, 100-180° C., the forming pressure may be, for example, 0.5-2.0 MPa, and the forming time may be, for example, 10-60 minutes.

<Final Processing Process>

The inside of the inner mold 31 is decompressed, the airtightness is released, the strip S formed by the rubber sleeve 35 between the inner mold 31 and the outer mold 32 is taken out, the strip S is cut into a wheel shape according to the specified width, and the inside and outside Flip over to make V-belt B.

-Example-

[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. Table 1 also shows the details of each.

<Example 1-1>

CR latex (trade name: Chloroprene 842A manufactured by Showa Denko Co., Ltd.) is mixed with an aqueous dispersion of cellulose microfibers (manufactured by Daio Paper Co., Ltd.) produced by mechanical defibration, and the water is vaporized to produce cellulose microfibers/ CR masterbatch.

Then, CR (manufactured by Showa Denko Co., Ltd., trade name: Chloroprene GS) was masticated, and a masterbatch was put therein and kneaded. Regarding the input amount of the masterbatch, when the total amount of CR is 100 parts by mass, the content of the cellulose-based ultrafine fibers is 20 parts by mass.

Then, CR and cellulose microfibers were kneaded, and 20 parts by mass of carbon black HAF (trade name: SEAST3 manufactured by Tokai Carbon Co., Ltd.) , 5 parts by mass of aromatic polyamide staple fiber (Technora (registered trademark) produced by Teijin Corporation), 5 parts by mass of oil (trade name: SUNPAR2280 produced by Japan's SUN Petroleum Co., Ltd.), 5 parts by mass of oxidation accelerator as a vulcanization accelerator Zinc (manufactured by Kai Chemical Industry Co., Ltd.) and 4 parts by mass of magnesium oxide (trade name: Kyowamag 150 produced by Kyowa Chemical Industry Co., Ltd.) were continuously kneaded to prepare an uncrosslinked rubber composition.

This uncrosslinked rubber composition was molded into a sheet shape, and as an uncrosslinked rubber sheet constituting the belt main body (compressive rubber layer, adhesive rubber layer, and tensile rubber layer), the cut edge of Example 1-1 was produced. V-belt.

In addition, as the core thread, a polyester fiber twisted thread subjected to bonding treatment was used.

<Example 1-2>

CR and 10 parts by mass of cellulose microfibers produced by a chemical defibrillation method (TEMPO oxidation treatment), 20 parts by mass of carbon black HAF as a reinforcing material, 5 parts by mass of CR relative to 100 parts by mass of the CR Oil, 5 parts by mass of zinc oxide as a vulcanization accelerator, and 4 parts by mass of magnesium oxide were kneaded and pressurized to prepare an uncrosslinked rubber composition.

The edge-cut V-belt of Example 1-2 having the same structure as that of Example 1-1 was produced except that this uncrosslinked rubber composition was used as the uncrosslinked rubber sheet constituting the belt main body.

<Example 1-3>

As the uncrosslinked rubber sheet for forming the belt main body, except that carbon black is not compounded and the content of cellulose-based microfibers chemically defibrated is set to 20 parts by mass relative to 100 parts by mass of the rubber component, The belt of Example 1-3 having the same structure as that of Example 1-2 was produced.

<Example 1-4>

As an uncrosslinked rubber sheet for constituting the belt main body, in addition to setting 10 parts by mass of aramid short fibers with respect to 100 parts by mass of the rubber component and also blending 10 parts by mass of nylon short fibers (produced by TORAY Co., Ltd. The belt of Example 1-4 having the same structure as that of Example 1-2 was produced except that short fibers of 3 mm in length were cut from the tire cord made of nylon 66.

<Example 1-5>

Example 1-2 with the same structure as Example 1-2 was produced except that 20 parts by mass of nylon short fibers were blended instead of 20 parts by mass of aramid short fibers as the non-crosslinked rubber sheet for constituting the belt main body. 5 straps.

<Comparative example 1-1>

A belt of Comparative Example 1-1 having the same structure as that of Example 1-1 was produced except that cellulose-based microfibers were not blended as the non-crosslinked rubber sheet constituting the main body of the belt.

<Comparative example 1-2>

As the uncrosslinked rubber sheet for constituting the belt main body, except that the blending amount of carbon black HAF was set to 70 parts by mass relative to 100 parts by mass of the rubber component, Comparative Example 1-1 having the same structure as Comparative Example 1-1 was produced. 2 straps.

<Comparative example 1-3>

As the non-crosslinked rubber sheet for constituting the belt main body, except that 20 parts by mass of nylon short fibers were blended instead of 20 parts by mass of aramid short fibers, Comparative Example 1-1 having the same structure as Comparative Example 1-1 was produced. 3 straps.

<Comparative example 1-4>

As an uncrosslinked rubber sheet for constituting the belt main body, except that the blending amount of carbon black HAF is set to 70 parts by mass with respect to 100 parts by mass of the rubber component and 20 parts by mass of aramid short fibers are blended instead of 20 parts by mass A belt of Comparative Example 1-4 having the same structure as that of Comparative Example 1-2 was produced except for the nylon staple fiber of 20 parts.

<Comparative example 1-5>

As the uncrosslinked rubber sheet for constituting the main body of the belt, in addition to 20 parts by mass of cellulose fibers (with a fiber diameter of about 10 to 100 μm) relative to 100 parts by mass of the rubber component (Daio Paper Co., Ltd. Kraft pulp production), the belt of Comparative Example 1-5 having the same structure as Comparative Example 1-1 was produced.

<Comparative example 1-6>

As an uncrosslinked rubber sheet for constituting the belt main body, except that carbon black HAF was not blended and 20 parts by mass of cellulose fibers other than microfibers were blended with respect to 100 parts by mass of the rubber component, the same as Comparative Example 1- 5 Belts of Comparative Examples 1-6 having the same structure.

<Comparative Examples 1-7>

A belt of Comparative Example 1-7 having the same structure as that of Example 1-2 was produced except that short aramid fibers were not blended as the non-crosslinked rubber sheet constituting the main body of the belt.

<Comparative Examples 1-8>

A belt of Comparative Example 1-8 having the same structure as that of Example 1-2 was produced except that carbon black HAF and short aramid fibers were not blended as the non-crosslinked rubber sheet constituting the main body of the belt.

[Table 1]

*In a short period of time (about 30 minutes), it often breaks and cannot be measured

(Test Evaluation Method)

Table 1 shows various evaluation results.

<Average fiber diameter, fiber diameter distribution>

After the samples of the inner rubber layers of the respective belts of Examples 1-1 to 1-5 were frozen and pulverized, their cross-sections were observed with a transmission electron microscope (TEM), and 50 cellulose ultrafine fibers were arbitrarily selected to measure the fiber diameter, The average value was obtained as the average fiber diameter. In addition, the maximum and minimum values of the fiber diameters among the 50 cellulose ultrafine fibers were obtained.

<Crack Resistance Evaluation Tape Running Test>

The crack life of the belt is an index showing the crack resistance of the rubber, and the longer the life, the better it is.

FIG. 9 shows a running tester 40 for measuring crack life. A belt running tester 40 for evaluating crack resistance has a pulley diameter A driving pulley 41 with a diameter of 40 mm and a driven pulley 42 with a pulley diameter of 40 mm arranged on the right side thereof. The driven pulley 42 is movable left and right so that it can receive an axial load (self-weight DW) and apply tension to the trimmed V-belt B. As shown in FIG.

The respective 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 running test machine 40, and the driven pulley 42 was directed to An axial load of 600 N was applied to the right side, tension was applied to the belt, and the drive pulley 41 was rotated at 3000 rpm at an ambient temperature of 100° C., thereby running the belt. Then, the belt was stopped at regular intervals, and whether or not cracks occurred on the edge-cut V-shaped belt B was visually checked, and the belt running time until the cracks were confirmed was defined as the anti-crack life. In addition, when the occurrence of cracks was not confirmed over 200 hours, the test was terminated at that point.

<High Tension Belt Running Test>

High-tension durability evaluation under self-weight conditions is effective as an accelerated evaluation of belt performance and life. Assuming that the change in belt length due to the permanent stretch of the core wire is constant, the greater the permanent deformation and wear of the rubber member, the greater the change in the interaxial distance before and after operation. Therefore, the smaller the change in the interaxial distance before and after the operation, the better. The mass change of the belt before and after running is an index showing the wear resistance of the rubber member, and the smaller the better.

FIG. 10 shows a high tension belt running tester 50 .

Two-axis designed high tension belt running tester 50 with pulley diameter A driving V-pulley 51 with a diameter of 100 mm and a driven V-pulley 52 with a pulley diameter of 60 mm arranged on the right side thereof. The driven V-pulley 52 is provided so as to be movable left and right so as to receive an axial load (self-weight DW) and apply tension to the belt.

The mass of each belt B in Examples 1-1 to 1-6 and Comparative Examples 1-1 to 1-4 before operation was measured as the initial mass.

Then, the belt was mounted on a high tension belt running tester 50, and the following interaxial load was applied to the driven pulley. That is, in the examples (Examples 1-1 to 1-3, Comparative Examples 1-1 and 1-2) where aramid staple fibers were blended alone, 1000N was applied, and when aramid staple fibers and nylon staple fibers were blended, Both examples (Example 1-4, Comparative Example 1-5, and 1-6) applied 800N, and in the example of blending nylon staple fiber alone (Example 1-5, Comparative Example 1-3, and 1-4) 500N was applied in , and 500N was applied in the examples (Comparative Examples 1-7 and 1-8) in which short fibers were not blended.

First, the ambient temperature was set at 100° C., and the driving pulley was operated at 5000 rpm for 10 minutes as a no-load state, and the interaxial distance was measured as an initial interaxial interdistance.

Then, the driving V-pulley 51 was rotated at 5000 rpm while the following load was applied to the driven V-pulley 52 . That is, 40 Nm was applied in the examples (Examples 1-1 to 1-3, Comparative Examples 1-1 and 1-2) in which aramid staple fibers were blended alone, and in the blending of aramid staple fibers and nylon staple fibers In both examples (Example 1-4, Comparative Examples 1-5 and 1-6), 30 Nm was applied. 20 Nm was applied in the case where nylon staple fiber was blended alone (Example 1-5, Comparative Examples 1-3 and 1-4), and 20 Nm was applied in the case where no short fiber was blended (Comparative Examples 1-7 and 1-8) .

After running for 200 hours, measure the interaxial distance when the machine continues to operate without load for 10 minutes, and take it as the interaxial distance after operation.

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

Interaxial change (%)

= (axis spacing after operation - axis spacing before operation) / axis spacing before operation × 100

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

Belt weight change (%)

= (belt weight before operation - belt weight after operation) / belt weight before operation × 100

Among them, in Comparative Examples 1-7 and 1-8, the belt was 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.

<Friction Coefficient>

Fig. 11 shows the friction coefficient measuring device.

The friction coefficient measuring device 40 is composed of a test pulley 82 and a load cell 83 provided on one side thereof. The test pulley 82 is composed of a rib pulley with a pulley diameter of 75 mm. The test pulley 82 is made of ferrous material S45C. The test piece 81 of the trimmed V-belt extends horizontally from the load cell 83 and is wound on the test pulley 82 , that is, it is installed so that the winding angle with respect to the test pulley 82 is 90°.

Each of the non-running edge-cut V-belts of Examples 1-1 to 1-6 and Comparative Examples 1-1 to 1-4 was cut to make a test piece 81 of the edge-cut V-belt, and one end thereof was fixed to a load cell. 83, then wound on the test pulley 82, and a weight 84 is suspended at the other end. Then, at an ambient temperature of 25° C., the test pulley 82 was rotated at a speed of 43 rpm in a direction in which the weight 84 was lowered, and the test pulley 82 of the test piece 81 was detected by the load cell 83 at 60 seconds after the start of the rotation. The tension Tt borne by the horizontal portion between the load cell 83 and the load cell 83. In addition, the tension Ts applied to the vertical part of the test pulley 82 and the weight 84 of the test piece 81 was the weight of the weight 84 of 17.15N. Then, based on Euler's formula, the friction coefficient μ when the surface of the compression rubber layer was dry was obtained by the following formula (1). Also, θ=π/2.

In addition, the same test was performed on the edge-cut V-belt after the high-tension belt running test, and the coefficient of friction when the surface of the inner rubber layer was dry was obtained. Then, the ratio of the coefficient of friction (coefficient of friction (after operation)/coefficient of friction (non-operation)) between the coefficient of friction when drying without operation and the coefficient of friction when drying after operation was obtained. The ratio of the friction coefficient before and after the operation is an index of the change in the friction coefficient, and the closer the ratio is to 1, the more stable the power transmission performance is, which is preferable.

[Formula 1]

<Adhesive wear>

After the high-tension belt running test, the belt was removed from the high-tension belt running tester 50, and it was visually checked whether or not adhesive wear of the rubber occurred at the contact portion with the pulley and the surface of the pulley.

The presence or absence of adhesive wear after the high-tension running test is an index showing the adhesive wear resistance of the rubber. Adhesive wear is a cause of abnormal sound, vibration, and fixation to the pulley of the belt, and it is preferable that adhesive wear does not occur.

<Strength Retention>

After the high-tension belt running test, carry out the belt tensile test, divide the breaking strength of the belt by the number of core wires embedded in the broken part, and measure the strength of one core wire after running.

In addition, the strength of one core wire before operation of the belt of the same batch was measured in the same manner, and the strength retention rate of the belt was obtained as follows. Table 1 shows the results.

Belt strength retention rate (%)

=Strength of one core wire after operation/Strength of one core wire before operation×100

The strength retention rate of the belt after the high-tension running test is an index showing the magnitude of damage to the tensile member (core wire) in the test. In the case of a V-belt, the local deformation of the core wire becomes larger due to bending caused by permanent deformation of the bottom rubber, and the winding diameter relative to the pulley becomes smaller due to wear of the rubber, so the core wire increases. deformed and damaged. In addition, if the coefficient of friction of the rubber becomes large and the separation from the pulley is poor when the belt is separated from the pulley, it will cause reverse bending stimulation and promote core wire fatigue. This is a composite effect, and therefore, it can be judged that the higher the strength retention rate of the belt is, the higher the performance of the rubber covering the core wire is.

(test evaluation results)

Table 1 shows the experimental results.

It can be seen from Table 1 that the distribution of the fiber diameters of the cellulose ultrafine fibers of Examples 1-1 to 1-5 is relatively wide.

In Examples 1-1 to 1-5 in which cellulose-based ultrafine fibers and other short fibers were used together, the belt crack life was 200 hours or more. In addition, after the high-tension running test, the change of the interaxial distance is 1-2%, the change of the belt weight is 2-3%, no adhesive wear occurs, and the strength retention rate of the belt is 88-90%. In addition, the ratio of the coefficient of friction before and after the high-tension running test was 0.95. In each example, the type of cellulose-based ultrafine fiber (mechanical defibration and chemical defibration) and the type of short fiber (aramid short fiber and nylon short fiber) were different, but good results were obtained in all of them. In the case of Example 1-3, carbon black was not added, and compared with other examples (1-2, 1-4, 1-5) using the same type of cellulose-based ultrafine fibers, cellulose was increased. The compounding amount of superfine fiber. That is, carbon black can be completely replaced by cellulose-based ultrafine fibers. In this case, as in the results of other examples, it is possible to provide a rubber composition that does not use carbon black.

In contrast, Comparative Examples 1-1 to 1-4 were reinforced with aramid short fibers or nylon short fibers, but the belts were made of rubber that did not incorporate cellulose-based ultrafine fibers.

In Comparative Examples 1-1 and 1-3 in which the compounding amount of carbon black was 20 parts by mass, the belt crack resistance life was more than 200 hours, same as the examples, no adhesive wear, and the coefficient of friction ratio was 0.9, compared with the examples similar. However, the mass change of the belt before and after the high-tension running test was 20%, and the wear resistance of the rubber was extremely poor. As a result, the variation in the interaxial distance was also large, 20%. Furthermore, the strength retention rate after operation was extremely low at 31 or 33%. The reason for this is that an excessively high coefficient of friction leads to poor separation from the pulley and bending deformation of the rubber, thus promoting fatigue of the core wire.

On the contrary, in the case of Comparative Examples 1-2 and 1-4 in which the blending amount of carbon black was 70 parts by mass, the wear resistance of the rubber (change in belt mass) could be improved by 3%, but the belt crack resistance Lifespan deterioration is 10 or 20. In addition, the interaxial distance of the belt varies greatly by 10%. This is because the permanent deformation of the rubber is large due to the high self-heating of the rubber during operation. Furthermore, adhesive wear occurs and the coefficient of friction changes. The belt strength retention rate after operation was also low at 42 or 48%. The reasons for this are that separation from the pulley deteriorates due to an increase in the coefficient of friction and self-heating of the rubber promotes fatigue of the core wire.

Next, Comparative Examples 1-5 and 1-6 are examples in which kraft pulp was used as relatively large-sized cellulose instead of cellulose-based microfibers. The difference between Comparative Examples 1-5 and Comparative Examples 1-6 lies in the presence or absence of compounding of carbon black. The crack life and wear resistance of both examples deteriorated. In addition, the belt strength retention rate is also low, which promotes the fatigue of the core wire. The reason is the same as in Comparative Examples 1-1 and 1-3.

Comparative Examples 1-7 and 1-8 are examples in which cellulose-based microfibers are blended without reinforcement by short fibers. The difference between Comparative Examples 1-7 and Comparative Examples 1-8 lies in the presence or absence of compounding of carbon black. In both examples, the belt crack life was good at 200 hours or more. However, in the high tension running test under high tension and high load conditions, the belt was broken in a short time, and the results of each item could not be measured. The reason for this is that the modulus of elasticity of the bottom rubber is insufficient, and the rubber bends and deforms.

As mentioned above, in Comparative Examples 1-1 to 1-8, the reinforcement method using carbon black and staple fibers (nylon staple fibers, aramid staple fibers) and the reinforcement method based on cellulose fibers other than ultrafine fibers (including the two cases of adding carbon black or not) and the reinforcement method using cellulose-based ultrafine fibers instead of other short fibers (including the two cases of adding carbon black or not) cannot satisfy all the desired properties at the same time. In particular, the performance cannot be satisfied in such a high-temperature environment (100° C.) as the test conditions of this example, and it is necessary to limit the use conditions to low temperatures.

In contrast, by substituting part or all of carbon black with cellulose-based microfibers, it functions together with a reinforcement method based on short fibers, and all desired performances can be satisfied at the same time. However, this needs to be achieved under the high temperature conditions of this embodiment.

The specific mechanism remains to be elucidated, but it is considered that the reinforcement based on cellulose-based ultrafine fibers is different from the reinforcement based on carbon black in the way of reinforcement. That is, the rubber layer (bonded rubber) adsorbed by carbon black suppresses the mobility of the rubber, thereby exhibiting carbon black reinforcement. In addition, considering that chemical crosslinking does not occur in the rubber layer, heat generation becomes large during repeated deformation, and adhesive wear occurs. In contrast, the details of the reinforcement based on cellulose-based microfibers are unclear, so the results this time are hard to predict. However, based on the results, the mobility of the rubber molecules near the cellulose-based ultrafine fibers may not be suppressed like that of the rubber molecules near carbon black, or they may be crosslinked to ensure properties as a rubbery elastic body. The reinforcement effect based on cellulose-based ultrafine fibers may also be brought about by the three-dimensional network structure of the ultrafine fibers. However, there is no particular relationship between the effect and the mechanism of the simultaneous use of cellulose-based microfibers and short fibers.

In addition, Example 1-1 in which 20 parts by mass of cellulose-based ultrafine fibers based on a mechanical defibrating method was blended with respect to 100 parts by mass of the rubber component was mixed with 10 parts by mass of cellulose-based ultrafine fibers based on a chemical defibrating method. The evaluation contents of Examples 1-2 of fine fibers are basically the same. Therefore, obtaining cellulose-based microfibers based on the chemical defibrillation method can achieve the same effect with a small amount of compounding.

[Test Evaluation 2]

Belts of Examples 2-1 to 2-5 and Comparative Examples 2-1 to 2-8 were produced using rubber compositions containing hydrogenated NBR (H-HBR) as a rubber component. Table 2 shows the details of each.

<Example 2-1>

Mix H-HBR latex (trade name: ZLX-B produced by ZEON Corporation of Japan) with an aqueous dispersion of cellulose microfibers produced by mechanical defibrillation, and vaporize the water to produce cellulose microfibers/H-HBR masterbatch.

Then, H-HBR (trade name: Zetpol 2020 produced by ZEON Corporation, Japan) was masticated, and a masterbatch was put into it for kneading. Regarding the input amount of the masterbatch, when the total amount of H-HBR is 100 parts by mass, the content of cellulose microfibers is 20 parts by mass.

Then, H-HBR was kneaded with cellulose microfibers, and 20 parts by mass of carbon black HAF as a reinforcing material and 20 parts by mass of aromatic polyamide were respectively put into it with respect to 100 parts by mass of H-HBR. Amide short fiber, 10 parts by mass of oil, 5 parts by mass of organic peroxide (trade name produced by NOF Corporation: PEROXYMON F40) and 1 part by mass of auxiliary crosslinking agent (trade name produced by Seiko Chemical Co., Ltd.) : Hi-Cross M), kneading was continued to produce an uncrosslinked rubber composition.

This uncrosslinked rubber composition was molded into a sheet shape, and as an uncrosslinked rubber sheet constituting the belt main body (compressive rubber layer, adhesive rubber layer, and tensile rubber layer), the cut edge of Example 2-1 was produced. V-belt.

In addition, as the core thread, a twisted thread made of polyester fiber subjected to bonding treatment was used.

<Example 2-2>

10 parts by mass of CR and 10 parts by mass of cellulose microfibers produced by a chemical defibrillation 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 an auxiliary crosslinking agent were kneaded to prepare a non-crosslinked rubber composition.

The edge-cut V-belt of Example 2-2 having the same structure as that of Example 2-1 was produced except that this uncrosslinked rubber composition was used as the uncrosslinked rubber sheet constituting the belt main body.

<Example 2-3>

As the non-crosslinked rubber sheet for constituting the belt main body, except that carbon black is not compounded and the content of cellulose-based microfibers chemically decomposed by fiber is set to 20 parts by mass relative to 100 parts by mass of the rubber component, made with

The belt of embodiment 2-3 of embodiment 2-2 same structure.

<Example 2-4>

As the non-crosslinked rubber sheet for constituting the belt main body, except that 10 parts by mass of aramid staple fiber is provided with respect to 100 parts by mass of the rubber component, and 10 parts by mass of nylon staple fiber is also blended, production and example 2-2 The belt of embodiment 2-4 of the same structure.

<Example 2-5>

Example 2-2 with the same structure as Example 2-2 was produced except that 20 parts by mass of nylon short fibers were blended instead of 20 parts by mass of aramid short fibers as the uncrosslinked rubber sheet for constituting the belt main body. 5 straps.

<Comparative example 2-1>

As the non-crosslinked rubber sheet for constituting the belt main body, except that the blending amount of carbon black HAF was set to 30 parts by mass with respect to 100 parts by mass of the rubber component and cellulose-based ultrafine fibers were not blended, the same method as in Example 2 was produced. -1 The belt of Comparative Example 2-1 having the same structure.

<Comparative example 2-2>

As the non-crosslinked rubber sheet for constituting the belt main body, except that the blending amount of carbon black HAF was set to 90 parts by mass with respect to 100 parts by mass of the rubber component, Comparative Example 2-1 having the same structure as Comparative Example 2-1 was produced. 2 straps.

<Comparative example 2-3>

As an uncrosslinked rubber sheet for constituting the belt main body, except that 20 parts by mass of nylon short fibers were blended instead of 20 parts by mass of aramid short fibers, Comparative Example 2-1 having the same structure as Comparative Example 2-1 was produced. 3 straps.

<Comparative example 2-4>

As an uncrosslinked rubber sheet for constituting the belt main body, except that the compounding amount of carbon black HAF was set to 90 parts by mass with respect to 100 parts by mass of the rubber component and 20 parts by mass were compounded instead of 20 parts by mass of aramid short fibers A belt of Comparative Example 2-4 having the same structure as that of Comparative Example 2-1 was produced except for the nylon staple fiber of 10 parts.

<Comparative example 2-5>

As an uncrosslinked rubber sheet for constituting the belt main body, except that the compounding amount of carbon black HAF is set to 20 parts by mass relative to 100 parts by mass of the rubber component and 20 parts by mass of HAF is also compounded relative to 100 parts by mass of the rubber component Except for cellulose fibers other than microfibers, a belt of Comparative Example 2-5 having the same structure as that of Comparative Example 2-1 was produced.

<Comparative example 2-6>

As an uncrosslinked rubber sheet for constituting the belt main body, except that carbon black HAF is not blended and 20 parts by mass of cellulose fibers other than microfibers are blended with respect to 100 parts by mass of the rubber component, the same as Comparative Example 2- 1 Belts of Comparative Examples 2-5 having the same structure.

<Comparative example 2-7>

A belt of Comparative Example 2-7 having the same structure as that of Example 2-2 was produced except that short aramid fibers were not blended as the non-crosslinked rubber sheet constituting the main body of the belt.

<Comparative example 2-8>

A belt of Comparative Example 2-8 having the same structure as that of Example 2-2 was produced except that carbon black HAF and aramid short fibers were not blended as the non-crosslinked rubber sheet constituting the main body of the belt.

[Table 2]

*Within a short period of time (around 30 minutes) the band breaks and cannot be measured

(Test Evaluation Method)

In the same manner as in Test Evaluation 1, the average value, minimum value, and maximum value of the fiber diameters of the cellulose ultrafine fibers of the tapes of Examples 2-1 to 2-5 were determined. In addition, similarly to Test Evaluation 1, the belt cracking life of each belt in Examples 2-1 to 2-5 and Comparative Examples 2-1 to 2-8 was obtained, and a high-tension running test was performed to evaluate changes in the interaxial distance. , quality change, wear coefficient ratio, adhesive wear after test, strength retention rate.

However, the ambient temperature for measuring the belt crack life and the high-tension running test was set to 120°C. In addition, the belt crack life was measured up to 300 hours, and when no cracks were confirmed even after 300 hours, the test was terminated.

(test evaluation results)

Table 2 shows the experimental results.

From Table 2, it can be seen that even when the rubber component is set to H-HBR, the same results as in Test Evaluation 1 can be obtained. In particular, compared with Test Evaluation 1, good evaluation results were obtained even when the ambient temperature of the crack resistance evaluation belt running test and the high tension belt running test was higher (120° C.). The reason for this is that, as one possibility, the reinforcing effect of cellulose-based microfibers is less dependent on temperature than the reinforcing effect of carbon black.

[Test Evaluation 3]

Belts for test evaluation of Examples 3-1 to 3-5 and Comparative Examples 3-1 to 3-8 were produced using rubber compositions containing EPDM as a rubber component. Table 3 shows the details of each.

<Example 3-1>

A dispersion of cellulose microfibers produced by mechanical defibrillation in toluene is mixed with a solution of EPDM (trade name: EP33 produced by JSR Corporation) dissolved in toluene, and the toluene is vaporized to produce cellulose microfibers. Fiber/EPDM masterbatch.

Then, EPDM was masticated, and a masterbatch was put thereinto and kneaded. Regarding the input amount of the masterbatch, when the total amount of EPDM is 100 parts by mass, the content of cellulose microfibers is 20 parts by mass.

Then, EPDM and cellulose microfibers were kneaded, and 20 parts by mass of carbon black as a reinforcing material, 20 parts by mass of aramid short fibers, 10 The mass parts of oil, 5 mass parts of organic peroxide as a crosslinking agent, and 1 mass part of an auxiliary crosslinking agent were continuously kneaded to prepare an uncrosslinked rubber composition.

This uncrosslinked rubber composition was molded into a sheet shape, and as an uncrosslinked rubber sheet for constituting the belt main body (compressive rubber layer, adhesive rubber layer, and tensile rubber layer), the cut edge of Example 3-1 was produced. V-belt.

In addition, as the core thread, a twisted thread made of polyester fiber subjected to bonding treatment was used.

<Example 3-2>

With respect to 100 parts by mass of EPDM, 10 parts by mass of cellulose ultrafine fibers produced by a chemical defibrillation 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 An uncrosslinked rubber composition was prepared by using an organic peroxide as a crosslinking agent and 1 part by mass of an auxiliary crosslinking agent.

The edge-cut V-belt of Example 3-2 having the same structure as that of Example 3-1 was produced except that this uncrosslinked rubber composition was used as the uncrosslinked rubber sheet constituting the belt main body.

<Example 3-3>

As the non-crosslinked rubber sheet for constituting the belt main body, except that carbon black is not compounded and the content of cellulosic microfibers that undergo chemical fiber decomposition is set to 20 parts by mass relative to 100 parts by mass of the rubber component, The tape of Example 3-3 having the same structure as that of Example 3-2 was produced.

<Example 3-4>

As the non-crosslinked rubber sheet for constituting the belt main body, except that 10 parts by mass of aramid staple fiber is provided with respect to 100 parts by mass of the rubber component, and 10 parts by mass of nylon staple fiber is also blended, production and example 3-2 The belt of embodiment 3-4 of the same structure.

<Example 3-5>

Example 3-2 with the same structure as Example 3-2 was produced except that 20 parts by mass of nylon short fibers were blended instead of 20 parts by mass of aramid short fibers as the non-crosslinked rubber sheet for constituting the belt main body. 5 straps.

<Comparative example 3-1>

As the uncrosslinked rubber sheet for constituting the belt main body, except that the blending amount of carbon black HAF was set to 30 parts by mass with respect to 100 parts by mass of the rubber component, and cellulose-based ultrafine fibers were not blended, the same method as in Example 3 was produced. -1 The belt of Comparative Example 3-1 having the same structure.

<Comparative example 3-2>

Comparative Example 3-1 having the same structure as Comparative Example 3-1, except that the compounding amount of carbon black HAF was set to 90 parts by mass with respect to 100 parts by mass of the rubber component as the uncrosslinked rubber sheet for constituting the belt body. 2 straps.

<Comparative example 3-3>

Comparative Example 3-1 having the same structure as Comparative Example 3-1 was prepared except that 20 parts by mass of nylon short fibers were blended instead of 20 parts by mass of aramid short fibers as the non-crosslinked rubber sheet for constituting the belt main body. 3 straps.

<Comparative example 3-4>

As an uncrosslinked rubber sheet for constituting the belt main body, except that the blending amount of carbon black HAF is set to 90 parts by mass with respect to 100 parts by mass of the rubber component and 20 parts by mass of aramid short fibers are blended instead of 20 parts by mass A belt of Comparative Example 3-4 having the same structure as that of Comparative Example 3-1 was produced except for the nylon staple fiber of 20 parts.

<Comparative example 3-5>

As the uncrosslinked rubber sheet for constituting the belt main body, except that the blending 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 carbon black HAF was also blended with respect to 100 parts by mass of the rubber component Except for cellulose fibers other than microfibers, a belt of Comparative Example 3-5 having the same structure as that of Comparative Example 3-1 was produced.

<Comparative example 3-6>

As the non-crosslinked rubber sheet for constituting the belt main body, except that carbon black HAF was not blended and 20 parts by mass of cellulose fibers other than ultrafine fibers were blended with respect to 100 parts by mass of the rubber component, the same method as in Comparative Example 3 was produced. -1 The belt of Comparative Example 3-5 having the same structure.

<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 short aramid fibers were not blended as the non-crosslinked rubber sheet constituting the main body of the belt.

<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 aramid short fibers were not blended as the non-crosslinked rubber sheet constituting the main body of the belt.

[table 3]

*Within a short period of time (around 30 minutes) the band breaks and cannot be measured

(Test Evaluation Method)

In the same manner as in Test Evaluation 1, the average value, minimum value, and maximum value of the fiber diameters of the cellulose ultrafine fibers of the tapes of Examples 3-1 to 3-5 were determined. In addition, similarly to Test Evaluation 1, the belt cracking life of each belt in Examples 3-1 to 3-5 and Comparative Examples 3-1 to 3-8 was obtained, and a high-tension running test was performed to evaluate changes in the interaxial distance. , quality change, wear coefficient ratio, adhesive wear after test, strength retention rate.

However, the ambient temperature for measuring the belt crack life and the high-tension running test was set to 120°C. In addition, the belt crack life was measured up to 300 hours, and when no cracks were confirmed even after 300 hours, the test was terminated.

(test evaluation results)

Table 3 shows the experimental results.

As can be seen from Table 3, even when the rubber component is set to EPDM, the same results as those in Test Evaluation 1 and 2 can be obtained. In particular, compared with Test Evaluation 1, good evaluation results were obtained even when the ambient temperature of the crack resistance evaluation belt running test and the high tension belt running test was higher (120° C.).

[Embodiment 2]

(ribbed belt B)

1 and 2 are diagrams showing a V-ribbed belt B according to the second embodiment.

The V-ribbed belt B according to Embodiment 2 may be, for example, an endless power transmission member used in an auxiliary drive belt transmission or the like installed 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 3000 mm, a belt width of 10 to 36 mm, and a belt thickness of 4.0 to 5.0 mm.

The V-ribbed belt B according to Embodiment 2 includes a V-ribbed belt main body 10 made of rubber. An adhesive rubber layer 12 in the middle and a back rubber layer 13 on the outer peripheral side of the belt. A core wire 14 is embedded in a middle portion in the thickness direction of the adhesive rubber layer 12 of the V-ribbed belt main body 10 so as to form a helix having a pitch in the belt width direction. In addition, instead of the back rubber layer 13, a back reinforcement cloth may be provided, and the V-ribbed belt body 10 is constituted by two layers 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 protrusion extending in the belt length direction and has a substantially inverted triangular cross-section, and are arranged in a row along the belt length direction. For each V-shaped rib 16, for example, the rib height is 2.0 to 3.0 mm, and the width between base ends is 1.0 to 3.6 mm. The number of 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 with a horizontally rectangular cross section, and its thickness is, for example, 1.0 to 2.5 mm. The back rubber layer 13 is also formed in a strip shape with a horizontally rectangular cross section, and has a thickness of, for example, 0.4 to 0.8 mm. From the viewpoint of suppressing the generation of sound during back driving, it is preferable to provide a weave pattern on the surface of the back rubber layer 13 .

The compression rubber layer 11, the adhesive rubber layer 12, and the back rubber layer 13 are formed from a rubber composition obtained by heating and pressurizing an uncrosslinked rubber composition in which various rubber compounding ingredients are mixed and kneaded. It is made by cross-linking with a cross-linking agent. The rubber compositions used to form the compression rubber layer 11, the adhesive rubber layer 12, and the back rubber layer 13 may be the same or different.

As 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, for example, ethylene-propylene copolymer (EPR), ethylene-propylene-diene terpolymer (EPDM), ethylene-octene copolymer, ethylene-butene copolymer and other ethylene-α-olefin elastomers, neoprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), hydrogenated acrylonitrile rubber (H- HBR) etc. The rubber component is preferably one of them or a mixture of two or more rubbers. Preferably, the rubber components of the rubber compositions used to form the compression rubber layer 11, the adhesive rubber layer 12, and the back rubber layer 13 are the same.

At least one of the rubber compositions for forming the compression rubber layer 11, the adhesive rubber layer 12, and the back rubber layer 13 contains cellulose-based ultrafine fibers whose fiber diameter distribution range includes 50 to 500 nm. It is preferable that all rubber compositions used for forming the compression rubber layer 11, the adhesive rubber layer 12, and the back rubber layer 13 contain cellulose-based microfibers, but it is more preferable to form at least the compression rubber layer 11 constituting the pulley contact portion. The rubber composition contains cellulosic microfibers.

According to the V-ribbed belt B according to Embodiment 2, as described above, at least one of the rubber compositions constituting the compression rubber layer 11, the adhesive rubber layer 12, and the back rubber layer 13 of the V-ribbed belt main body 10 contains Since the distribution range of the fiber diameter includes cellulose-based ultrafine fibers of 50 to 500 nm, excellent bending fatigue resistance can be obtained. In addition, especially in the case where the rubber composition forming the compression rubber layer 11 constituting the contact portion contains cellulose-based microfibers, high abrasion resistance can be obtained and a stable coefficient of friction can be obtained.

Cellulosic ultrafine fibers are fiber materials derived from cellulose ultrafine fibers composed of a skeleton component of plant cell walls obtained by finely dismantling plant fibers. Examples of raw material plants for cellulose-based ultrafine fibers include wood, bamboo, rice (straw), potatoes, sugar cane (bagasse), aquatic plants, and seaweed. Among them, wood is preferable.

The cellulose ultrafine fiber may be cellulose ultrafine fiber itself, or may be hydrophobized cellulose ultrafine fiber after hydrophobization treatment. In addition, as the cellulose-based ultrafine fibers, cellulose ultrafine fibers and hydrophobized cellulose ultrafine fibers may be used together. From the standpoint of dispersibility, the cellulose-based ultrafine fibers preferably include hydrophobized cellulose ultrafine fibers. Examples of the hydrophobized cellulose ultrafine fibers include cellulose ultrafine fibers in which a part or all of the hydroxyl groups of cellulose are substituted with hydrophobic groups, and cellulose ultrafine fibers subjected to a hydrophobizing surface treatment using a surface treatment agent.

As hydrophobization for obtaining cellulose microfibers in which a part or all of the hydroxyl groups of cellulose are replaced with hydrophobic groups, for example, esterification (acylation) (alkyl esterification, complex esterification, β- Keto esterification, etc.), alkylation, tosylation, epoxidation, arylation, etc. Among them, esterification is preferable. Specifically, esterified hydrophobized cellulose superfine fibers can be obtained by passing part or all of the hydroxyl groups of cellulose through carboxylic acids such as acetic acid, anhydrous acetic acid, propionic acid, butyric acid, or their halides (especially chlorides). Acylated cellulose microfiber. As a surface treatment agent for obtaining the cellulose ultrafine fiber which surface-treated to hydrophobize using a surface treatment agent, a silane coupling agent etc. are mentioned, for example.

From the viewpoint of improving the bending fatigue resistance, the cellulose-based ultrafine fibers preferably have a wide distribution of fiber diameters, and the distribution range of fiber diameters includes 50 to 500 nm. From the viewpoint of the above, the lower limit of the fiber diameter distribution is preferably 20 nm or less, more preferably 10 nm or less. From the same viewpoint, the upper limit is preferably 700 nm or more, more preferably 1 μm or more. The distribution range of the fiber diameter of the cellulose-based ultrafine fibers is preferably 20 nm to 700 mm, more preferably 10 nm to 1 μm.

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

After the sample of the rubber composition was frozen and pulverized, its cross-section was observed with a transmission electron microscope (TEM), and 50 cellulose-based ultrafine fibers were randomly selected to measure the fiber diameter. Based on the measurement results, the cellulose-based ultrafine fiber Fiber diameter distribution. In addition, the average of the fiber diameters of the 50 arbitrarily selected cellulose-based ultrafine fibers was determined as the average fiber diameter of the cellulose-based ultrafine fibers.

Cellulosic microfibers may be high-aspect-ratio cellulose microfibers produced by mechanical defibration, or needle-like crystals produced by chemical defibration. Among them, it is preferable to manufacture by a mechanical defibrating method. In addition, as the cellulose-based ultrafine fibers, cellulose-based ultrafine fibers produced by a mechanical defibrating method and cellulose-based ultrafine fibers produced by a chemical defibrating method may be used together. Examples of the defibrating apparatus used in the mechanical defibrating method include kneaders such as twin-screw kneaders, high-pressure homogenizers, grinders, sand mills, and the like. As the treatment used in the chemical defibrating method, for example, acid hydrolysis treatment and the like can be cited.

The content of the cellulose microfibers in the rubber composition is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and still more preferably 5 parts by mass relative to 100 parts by mass of the rubber component, from the viewpoint of improving the bending fatigue resistance. In addition, it is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, further preferably 10 parts by mass or less.

Examples of rubber compounding agents include reinforcing materials, processing oils, processing aids, vulcanization acceleration aids, crosslinking agents, vulcanization accelerators, anti-aging agents, and the like.

As a reinforcing material, in carbon black, for example, 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 carbon black, acetylene carbon black, etc. Silica can also be mentioned as a reinforcing material. The reinforcing material is preferably one or more than two of them. The content of the reinforcing material is preferably 50 to 90 parts by mass relative to 100 parts by mass of the rubber component of the rubber composition.

Examples of the oil include petroleum softeners, mineral oils such as paraffin oil, castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, peanut oil, tree wax, rosin oil , pine oil and other vegetable oils. The oil is preferably one or more of them. The content of the oil 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 processing aids include stearic acid, polyethylene wax, metal salts of fatty acids, and the like. Processing aids are preferably one or more of them. 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 accelerator include metal oxides such as zinc oxide (zinc white) and magnesium oxide, metal carbonates, fatty acids and derivatives thereof. The vulcanization accelerator is preferably one or more of them. The content of the vulcanization accelerator may be, for example, 3 to 7 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

As an antiaging agent, a benzimidazole type antiaging agent, an amine type antiaging agent, a diamine type antiaging agent, a phenol type antiaging agent etc. are mentioned, for example. The anti-aging agent is preferably one or two or more of them. The content of the antiaging agent may be, for example, 0.1 to 5 parts by mass with respect to 100 parts by mass of the rubber component.

Examples of auxiliary crosslinking agents include maleimides, TAIC, 1,2-polybutadiene, oximes, guanidine and trimethylolpropane trimethacrylate, liquid rubber, and the like. Auxiliary crosslinking agents are preferably one or more than two of them. The content of the auxiliary crosslinking agent may be, for example, 0.5 to 30 parts by mass relative to 100 parts by mass of the rubber component.

Examples of the crosslinking agent include sulfur and organic peroxides. As a crosslinking agent, sulfur may be added, an organic peroxide may be added, or both may be used in combination. The amount of the crosslinking agent may be, for example, 1 to 5 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition in the case of sulfur, or 1 to 5 parts by mass in the case of organic peroxides with respect to the rubber composition 100 parts by mass of the rubber component may be, for example, 1 to 5 parts by mass.

As the vulcanization accelerator, for example, thiurams (such as TETD, TT, TRA, etc.), thiazoles (such as MBT, MBTS, etc.), sulfenamides (such as CZ, etc.), dithiocarbamates (such as BZ-P, etc.) and so on. The vulcanization accelerator is preferably one or more of them. The content of the vulcanization accelerator may be, for example, 1 to 3 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

In the rubber composition constituting the compression rubber layer 11, the adhesive rubber layer 12, and the back rubber layer 13, short fibers 16 having a fiber diameter of 10 μm or more may be contained. In particular, it is preferable to contain the short fibers 16 in the rubber composition forming the compression rubber layer 11 constituting the pulley contact portion. In this case, the compressed rubber layer 11 preferably contains the short fibers 16 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 compressed rubber layer 11 preferably protrudes from the surface. In addition, the short fibers 16 may have a structure in which the short fibers are implanted on the surface of the V-shaped rib 15 of the compression rubber layer 11 instead of being blended with the rubber composition.

Examples of the staple fibers 16 include nylon staple fibers, vinylon staple fibers, aramid staple fibers, polyester staple fibers, and cotton staple fibers. For example, the short fibers 16 can be produced by cutting long fibers that have been subjected to a bonding treatment of immersion in an RFL aqueous solution or the like and then heated to a predetermined length. The length of the short fibers 16 may be, for example, 0.2 to 5.0 mm, and the fiber diameter may be, for example, 10 to 50 μm.

The content of short fibers 16 is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and preferably 30 parts by mass or less, more preferably 20 parts by mass or less, based on 100 parts by mass of the rubber component. The content of short fibers 16 is preferably larger than the content of cellulose-based ultrafine fibers. The ratio of the content of short fibers 16 to the content of cellulose ultrafine fibers (the content of short fibers 16 relative to the content of cellulose ultrafine fibers) is preferably 1 or more, more preferably 2 or more, and preferably 15 or less, more preferably 5 or less. The total content of cellulosic microfibers and short fibers 16 is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and preferably 25 parts by mass or less, more preferably 15 parts by mass relative to 100 parts by mass of the rubber component. the following.

The core wire 14 is constituted by a twisted yarn formed of polyamide fiber, polyester fiber, aramid fiber, polyamide fiber, or the like. The diameter of the core wire 14 may be, for example, 0.5-2.5 mm, and the dimension between the centers of adjacent core wires 14 in the cross section may be, for example, 0.05-0.20 mm. The core wire 14 is subjected to an adhesive treatment to be adhesive to the V-ribbed belt main body 10 .

Next, FIG. 12 shows a pulley design of an auxiliary drive belt transmission 20 for an automobile using the V-ribbed belt B according to the second embodiment. This auxiliary machine drive belt transmission 20 is a serpentine drive type device that transmits power by winding a V-ribbed belt B around six pulleys including four rib pulleys and two flat pulleys.

In this auxiliary machine drive belt transmission 20 , a power steering pulley 21 as a rib pulley is provided at the uppermost position, and an AC generator pulley 22 as a rib pulley is provided below the power steering pulley 21 . Further, a tension pulley 23 as a flat pulley is provided on the lower left of the power steering pulley 21 , and a water pump pulley 24 as a flat pulley is provided below the tension pulley 23 . Further, a crank pulley 25 as a rib pulley is provided on the lower left of the tension pulley 23 , and an air conditioner pulley 26 as a rib pulley is provided on the lower right of the crank pulley 25 . These pulleys can be made of, for example, metal stamped parts, castings, or resin molded products such as nylon resin and phenol resin. In addition, the diameter of the pulley It can be 50-150mm.

In addition, in this auxiliary machine drive belt transmission 20, the V-ribbed belt B is wound around the power steering pulley 21 so that the side of the V-shaped rib 16 is in contact, and then wound around the V-shaped rib 16 so that the back side thereof is in contact with the V-rib. After the pulley 23 is tightened, it is wound on the crankshaft pulley 25 and the air conditioner pulley 26 successively in a manner of contacting the side of the V-shaped rib 16, and then wound on the water pump pulley 24 in a manner of contacting the back side of the belt, and then , winds on the AC generator pulley 22 in such a way that the V-shaped rib 16 side contacts, and finally returns to the power steering pulley 21 . The length of the V-ribbed belt B stretched between the pulleys, that is, the span length of the belt, may be, for example, 50 to 300 mm. The axial center difference that can occur between the pulleys can be 0 to 2°.

(Manufacturing method of V-belt B)

The method of manufacturing the V-ribbed belt B according to the second embodiment is the same as that of the V-ribbed belt according to the first embodiment.

-Example-

[ribbed belt]

The V-ribbed belts of the following Examples 4-1 to 4-9 and Comparative Example 4 were produced. Details are shown in Table 4.

<Example 4-1>

Prepare a dispersion of powdered cellulose (manufactured by Nippon Paper Co., Ltd.: KCFLOCK W-50GK) dispersed in toluene, and use a high-pressure homogenizer to collide the dispersion with each other to separate the powdered cellulose. Cellulose ultrafine fibers were formed to obtain a dispersion in which cellulose ultrafine fibers were dispersed in toluene. Thus, cellulose microfibers were produced by a mechanical defibration method, and no hydrophobizing treatment was performed.

Then, this dispersion in which cellulose microfibers were dispersed in toluene was mixed with a solution in which ethylene-propylene-diene rubber (trade name: EP33 manufactured by JSR Corporation, hereinafter referred to as "EPDM") was dissolved in toluene, and the toluene was vaporized. , to make masterbatch of cellulose microfiber/EPDM.

Then, EPDM was masticated, and a masterbatch was put thereinto and kneaded. Regarding the input amount of the masterbatch, when the total amount of EPDM is 100 parts by mass, the content of cellulose microfibers is 1 part by mass.

Then, EPDM and cellulose microfibers were kneaded, and 60 parts by mass of HAF carbon black (trade name produced by Mitsubishi Chemical Corporation: Diablack H), 15 parts by mass of EPDM relative to 100 parts by mass of EPDM, and 15 parts by mass were added thereto. Oil (trade name: SUNPAR2280 manufactured by Sun Petroleum Co., Ltd.), 1 part by mass of stearic acid (trade name manufactured by Shin Nippon Chemical Co., Ltd.: stearic acid 50S) as a processing aid, 5 parts by mass of oxidation-promoting agent as a vulcanization accelerator Zinc (trade name produced by Kai Chemical Co., Ltd.: three kinds of zinc oxide), 2.5 parts by mass of benzimidazole anti-aging agent (trade name produced by Ouchi Shining Chemical Industry Co., Ltd.: NocracMB), 2.3 parts by mass of sulfur as a crosslinking agent (trade name produced by Hosoi Chemical Co., Ltd.: oil sulfur) and 2 mass parts of thiuram vulcanization accelerators (trade name produced by Ouchi Shining Chemical Industry Co., Ltd.: Nocseller TET-G), continue to knead, thereby making uncrosslinked rubber composition.

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

For the V-ribbed belt of Example 4-1, the belt length is 1400mm, the belt width is 2.2mm, the belt thickness is 4.5mm, and the number of V-shaped ribs is 3. In addition, the adhesive rubber layer and the back rubber layer are formed of a rubber composition that does not contain cellulose microfibers and short fibers, and the core thread is formed of a twisted polyester fiber that has been 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 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 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 belt of Example 4-5 was produced in the same manner as in Example 4-1 except that the content of the cellulose ultrafine fibers was 15 parts by mass with respect to 100 parts by mass of the rubber component.

<Example 4-6>

The V-ribbed belt of Example 4-6 was produced in the same manner as in Example 4-1 except that the content of the cellulose microfiber was 25 parts by mass with respect to 100 parts by mass of the rubber component.

<Example 4-7>

Except that the uncrosslinked rubber composition used for the compression rubber layer contains 14 parts by mass of nylon short fibers (trade name produced by Teijin Corporation: CFN3000 fiber diameter: 26 μm fiber length: 3 mm) relative to 100 parts by mass of the rubber component, The V-ribbed belt of Example 4-7 was produced in the same manner as in Example 4-1. The ratio of the content of short fibers to the content of cellulose-based ultrafine fibers ("B/A" in Table 4) was 14. The total content of cellulosic ultrafine fibers and short fibers ("A+B" in Table 4) was 15 parts by mass relative to 100 parts by mass of the rubber component.

<Example 4-8>

The multi-rib of Example 4-8 was produced in the same manner as in Example 4-2, except that the non-crosslinked rubber composition used for the compression rubber layer contained 12 parts by mass of nylon short fibers relative to 100 parts by mass of the rubber component. bring. The ratio (B/A) of the short fiber content to the cellulose ultrafine fiber content was 4. The total content (A+B) of cellulose-based ultrafine fibers and short fibers was 15 parts by mass relative to 100 parts by mass of the rubber component.

<Example 4-9>

The multi-rib of Example 4-9 was produced in the same manner as in Example 4-3, except that 10 parts by mass of nylon staple fiber was contained in the uncrosslinked rubber composition for the compression rubber layer relative to 100 parts by mass of the rubber component. bring. The ratio of the content of short fibers to the content of cellulose-based ultrafine fibers (the content of short fibers relative to the content of cellulose-based ultrafine fibers) was 3. The total content of cellulose-based microfibers and short fibers was 15 parts by mass relative to 100 parts by mass of the rubber component.

<Comparative example 4>

Produced in the same manner as in Example 4-1, except that the non-crosslinked rubber composition used for the compression rubber layer did not contain cellulose microfibers and contained 15 parts by mass of nylon short fibers relative to 100 parts by mass of the rubber component. The V-ribbed belt of Comparative Example 4.

[Table 4]

(Test Evaluation Method)

<Average fiber diameter, fiber diameter distribution>

After the sample of the rubber composition of the compression rubber layer of each V-ribbed belt collected in Examples 4-1 to 4-5 was frozen and pulverized, the cross-section was observed with a scanning electron microscope (SEM), and 50 fibers were arbitrarily selected The fiber diameters were measured, and the average was obtained as the average fiber diameter. In addition, the maximum and minimum values of the fiber diameters among the 50 cellulose ultrafine fibers were obtained.

<Friction Coefficient Measurement Test>

FIG. 17 shows a friction coefficient measuring device 140 .

The friction coefficient measuring device 140 is composed of a test pulley 141 and a load cell 142 provided on one side thereof. The test pulley 141 is composed of a rib pulley with a pulley diameter of 75 mm. The test pulley 141 is made of iron-based material S45C. The test piece 143 of the V-ribbed belt extends horizontally from the load cell 142 and is wound around the test pulley 141 , that is, it is installed so that the winding angle with respect to the test pulley 141 is 90°.

Each V-ribbed belt of Examples 4-1 to 4-9 and Comparative Example 4 was cut to make a strip-shaped test piece 143, one end of which was fixed on the load cell 142, the test pulley 141 was wound, and the other end was hung Weight 144 is installed. Then, at an ambient temperature of 25° C., the test pulley 141 is rotated at a rotation speed of 43 rpm in a direction in which the weight 144 is lowered, and the test pulley 141 of the test piece 143 is detected by the load cell 142 at 60 seconds after the start of the rotation. The tension Tt borne by the horizontal portion between the load cell 142 and the load cell 142 . In addition, the tension Ts applied to the vertical portion between the test pulley 141 and the weight 144 of the test piece 143 was 17.15N which is the weight of the weight 144 . Then, based on Euler's formula, the friction coefficient μ when the surface of the compression rubber layer is dry is obtained by the following formula (2). Also, θ=π/2.

[Formula 2]

In addition, water was set on the test pulley 141, and the same test was carried out when the water was dry, and then the difference in which the coefficient of friction when dry was subtracted from the friction coefficient when water was dry was obtained.

<Abrasion Resistance Evaluation Tape Running Test>

Figure 18 shows the pulley design of a belt running tester 150 used to evaluate wear resistance. The belt running tester 150 for evaluating wear resistance has a pulley diameter A driving rib pulley 151 with a diameter of 60 mm and a driven rib pulley 152 with a pulley diameter of 60 mm arranged on its right side. The driven rib pulley 152 is movable left and right so that it can receive an axial load (self-weight DW) and apply tension to the V-ribbed belt B.

For each V-ribbed belt of Example 4-1 to Example 4-9 and Comparative Example 4, after measuring the quality of the belt, it was wound around the driving rib pulley 151 and the belt running tester 150 for evaluating wear resistance. Between the driven rib pulleys 152, the driven rib pulley 152 bears an axial load of 490N to the right, applies tension to the V-ribbed belt B, and applies a rotational load of 5.9kW (8PS). The rib wheel 151 rotates at 3500 rpm to run the belt. Then, 24 hours after the start of the operation, the belt operation was stopped, the belt mass of the V-ribbed belt was measured, and the percentage of mass reduction was obtained.

<Evaluation of bending fatigue resistance with running test>

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

The belt running tester 160 for evaluating bending fatigue resistance has a pulley diameter Be the driving rib pulley 161 of 60mm, the belt pulley diameter that is arranged on its top The first driven rib pulley 162a is 60mm, and the pulley diameter is set on the right side of the intermediate portion between the driving rib pulley 161 and the first driven rib pulley 162a The second driven rib pulley 162b of 60mm, and the pulley diameter arranged on the right side of the middle part between the drive rib pulley 161 and the first driven rib pulley 162a at intervals up and down A pair of guide wheels 163 with a diameter of 50mm respectively. The first driven rib pulley 162a is vertically movable so as to receive an axial load (self-weight DW) and apply tension to the V-ribbed belt B. In addition, in this belt running test machine 160 for evaluating bending fatigue resistance, the V-ribbed belt B is bent toward the back side, and the deformation of the front end of the V-shaped rib is increased to accelerate bending fatigue.

For each V-ribbed belt of Example 4-1 to Example 4-9 and Comparative Example 4, the compression rubber layer is in contact with the driving rib wheel 161, the first and second driven rib wheels 162a, 162b, and the back rubber layer is in contact with the rib wheel. The guide pulleys 163 are respectively wound on the belt running test machine 160 for evaluating the bending fatigue resistance. In addition, the first driven rib pulley 162a receives an axial load of 588N upward to apply tension to the V-ribbed belt B. , at an ambient temperature of 70° C., the driving rib pulley 161 was rotated at a rotational speed of 5100 rpm to run the belt. Then, the belt was periodically stopped, and the compression rubber layer was visually checked for cracks, and the belt running time until cracks were confirmed was defined as the crack occurrence life.

(test evaluation results)

Table 2 shows the experimental results. In addition, unless otherwise specified below, the content of cellulose ultrafine fibers means parts by mass relative to 100 parts by mass of the rubber component.

<Average fiber diameter, fiber diameter distribution>

The fiber diameter distribution of the cellulose ultrafine fibers contained in the rubber composition forming the compression rubber layer of each V-ribbed belt of Example 4-1 to Example 4-9 was wide.

<Friction Coefficient>

The friction coefficient of Comparative Example 4 was 0.6, whereas the friction coefficients of Examples 4-1 to 4-9 were in the range of 0.6 to 1.1, which was the same as Comparative Example 4 or slightly larger than that of Comparative Example 4. However, in all of Examples 4-1 to 4-9, the amount of change (amount of increase) between the friction coefficient when dry and the friction coefficient when water dried was smaller than 0.9 in Comparative Example 4. In particular, Examples 4-3 to 4-6 in which the content of cellulose microfibers is 5 parts by mass or more and Examples 4-7 to 4 containing both cellulose microfibers and nylon staple fibers In -9, the amount of increase is -0.05 to 0.05, which is close to 0. From this, it can be seen that the increase in the friction coefficient when the water dries after splashing can be suppressed. Even in the case of Example 4-1 in which the content of cellulose ultrafine fibers was the lowest (1 part by mass), the change in the coefficient of friction was 0.5, which was a value close to half of that of Comparative Example 4.

From this, it was found that by including cellulose microfibers in the rubber composition forming the compression rubber layer, the change in the coefficient of friction after splashing water can be suppressed. This effect can be exerted even when nylon staple fibers are not included but only cellulose microfibers are contained, or both nylon staple fibers and cellulose microfibers are contained.

<Wear resistance>

The amount of mass loss in Comparative Example 4, that is, the wear rate was 3.2%. In contrast, Example 4-1, in which the content of cellulose ultrafine fibers was 1 part by mass, could be improved to 2.8%. The content of cellulose microfibers increased, and the abrasion resistance improved (in Example 4-2 to Example 4-6, 2.7, 2.1, 1.9, 1.8, and 1.7 in this order). However, when the content of cellulose ultrafine fibers exceeds 10 parts by mass, even if the content is increased further, the improvement effect is small (Example 4-4 to Example 4-6).

In addition, the amount of mass loss in Comparative Example 4 containing 15 parts by mass of nylon staple fibers was 3.2%, and in Example 4-1 in which the content of cellulose microfibers was 1 part by mass was 2.8%. In Examples 4-7 in which the content of nylon short fibers was 14 parts by mass and the content of cellulose ultrafine fibers was 1 part by mass, it was 2.3%. That is, from this, it can be seen that abrasion resistance can be further improved by including both nylon short fibers and cellulose microfibers. From Examples 4-7 to 4-9, it can be seen that although the total content of cellulose ultrafine fibers and nylon short fibers is the same, increasing the content ratio of cellulose ultrafine fibers can more effectively improve the abrasion resistance.

<Bending Fatigue Resistance>

In Comparative Example 4, in which the content of nylon short fibers was 15 parts by mass, the crack generation life was 520 hours, whereas in Example 4-1, in which the content of cellulose ultrafine fibers was 1 mass part, the crack generation life was 520 hours. It was 1205 hours, an improvement of more than two times. By increasing the content of cellulose microfibers to 3 parts by mass, the life of crack generation can be further improved (Example 4-2), but, when continuing to increase, the life of crack generation becomes shorter instead (Example 4-3～Example 4-3). 4-6). However, even in Examples 4-6 in which the content of cellulose ultrafine fibers was 25 parts by mass, the crack occurrence life was 900 hours, which was significantly improved compared with Comparative Example 4.

From this, it can be seen that when cellulose microfibers and nylon staple fibers are used together, the bending fatigue resistance can be improved better than in Comparative Example 4. In addition, by increasing the ratio of the content of cellulose ultrafine fibers, the bending fatigue resistance can be improved (Example 4-7 to Example 4-9).

As described above, by including cellulose microfibers in the rubber composition forming the compression rubber layer, the stability of the coefficient of friction (suppression of changes caused by splashing water), abrasion resistance, bending fatigue resistance, etc. can be improved. V-ribbed belt.

[Embodiment 3]

(flat belt C)

FIG. 13 schematically shows a flat belt C according to the third embodiment. The flat belt C according to Embodiment 3 is, for example, a power transmission member requiring a long life and used under high load conditions such as drive transmission of blowers, compressors, generators, etc., and driving of auxiliary equipment of automobiles. For the flat belt C, for example, the belt length is 600-3000 mm, the belt width is 10-20 mm, and the belt thickness is 2-3.5 mm.

The flat belt C according to Embodiment 3 includes an inner rubber layer 121 on the inner peripheral side of the belt, an adhesive rubber layer 122 on the outer peripheral side of the belt, and an outer rubber layer 123 on the further outer peripheral side of the belt, which are laminated and integrated. Flat belt body 120 . In the adhesive rubber layer 122 , a core wire 124 is embedded so as to form a helix 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 with a horizontally rectangular cross section, and are formed of a rubber composition obtained by mixing various compounding agents with the rubber component and kneading them. The uncrosslinked rubber composition is heated and pressurized and crosslinked with a crosslinking agent. The thickness of the inner rubber layer 121 is preferably 0.3 mm or more, more preferably 0.5 mm or more, and preferably 3.0 mm or less, more preferably 2.5 mm or less. The thickness of the adhesive rubber layer 122 may be, for example, 0.6-1.5 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 whose fiber diameter distribution range includes 50 to 500 nm. It is preferable that all the rubber compositions forming the inner rubber layer 121, the adhesive rubber layer 122, and the outer rubber layer 123 contain cellulose-based ultrafine fibers, but it is more preferable that at least the rubber composition forming the inner rubber layer 121 contains cellulose-based ultrafine fibers. fiber.

The rubber composition forming inner rubber layer 121 , adhesive rubber layer 122 , and outer rubber layer 123 has the same structure as the rubber composition forming compression rubber layer 111 , adhesive rubber layer 112 , and rear rubber layer 113 in Embodiment 2. Cellulosic microfibers also have the same structure as Embodiment 2.

Short fibers 126 may be contained in the rubber composition forming the inner rubber layer 121 , the adhesive rubber layer 122 , and the outer rubber layer 123 . In particular, the short fibers 126 are preferably contained in the rubber composition forming the inner rubber layer 121 . 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 that of the second embodiment.

In addition, the core wire 124 has the same structure as Embodiment 2.

According to the flat belt C according to Embodiment 3, 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 main body 120 contains a fiber diameter Since the distribution range includes cellulose-based ultrafine fibers of 50 to 500 nm, excellent bending fatigue resistance can be obtained. In addition, especially when the rubber composition forming the inner rubber layer 121 constituting the contact portion contains cellulose-based microfibers, high abrasion resistance can be obtained and a stable friction coefficient can be obtained.

(Manufacturing method of flat belt C)

The manufacturing method of the flat belt C which concerns on Embodiment 3 is demonstrated based on FIG.14, FIG.15, and FIG.16.

The manufacturing method of the flat belt C according to Embodiment 3 includes a material preparation step, a molding step, a crosslinking step, and a final processing 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 fabricated in the same manner as in Embodiment 2, containing cellulose-based microfibers. In addition, by mixing various rubber compounding ingredients into the rubber component, kneading using a kneader such as a kneader or a Banbury mixer, and molding the obtained uncrosslinked rubber composition into a sheet form by calender molding or the like, Create sheets that do not contain cellulose-based microfibers.

In addition, as in Embodiment 2, the bonding process is performed on the core wire 124'.

<Molding process>

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

Then, as shown in FIG. 14(b), after the core wire 124' is wound helically on the non-crosslinked rubber sheet 122' for bonding the rubber layer, the rubber sheet for bonding the rubber layer is wound thereon. Uncrosslinked rubber sheet 122'.

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. As a result, the laminated molded body C' is formed on the cylindrical mold 145. As shown in FIG.

<Crosslinking process>

Next, as shown in FIG. 15 , after the laminated molded body C' on the cylindrical mold 145 is covered with a rubber sleeve 146, it is placed in a vulcanization tank and sealed, and the cylindrical mold 145 is heated by high-heat steam or the like. , and high pressure is applied to push the rubber sleeve 146 in the radial direction of the cylindrical mold 145 side. At this time, the uncrosslinked rubber composition of the laminated molded body C' flows, and the crosslinking reaction of the rubber component occurs, and the core wire 124' undergoes an adhesion reaction, thereby, as shown in FIG. A cylindrical strip S is formed on 145 .

<Grinding and final processing>

In the grinding and finishing process, the cylindrical mold 145 is taken out from the vulcanization tank, and after the cylindrical strip S formed on the cylindrical mold 145 is released from the mold, its outer peripheral surface and/or inner peripheral surface are ground, make the thickness uniform.

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

-Example-

[flat belt]

The following flat belts of Example 5-1 to Example 5-6 and Comparative Example 5-1 to Comparative Example 5-2 were produced. Table 5 shows the details of each.

<Example 5-1>

Similar to Example 4-1, a masterbatch of cellulose microfiber/EPDM was prepared.

Then, EPDM is masticated, and a masterbatch is put thereinto for kneading. With regard to the input amount of the masterbatch, when the total amount of EPDM is 100 parts by mass, the content of cellulose microfibers is 1 part by mass.

Then, EPDM and cellulose microfibers were kneaded, and 40 parts by mass of HAF carbon black (trade name: Diablack H produced by Mitsubishi Chemical Corporation) and 5 parts by mass of processing oil were dropped into it with respect to 100 parts by mass of EPDM. (SUN Petroleum Corporation product name: SUNPAR2280), 0.5 parts by mass of stearic acid as a processing aid (New Nippon Chemical Co., Ltd. product name: stearic acid 50S), 5 parts by mass of zinc oxide as a vulcanization accelerator (trade name produced by Jie Chemical Company: three kinds of zinc oxide), 2 parts by mass of benzimidazole anti-aging agent (trade name produced by Ouchi Shining Chemical Industry Co., Ltd.: NocracMB) and 6 parts by mass of organic polymer as crosslinking agent Oxides (trade name manufactured by NOF Corporation: PEROXYMONF-40, purity: 40% by mass) were kneaded continuously to prepare an uncrosslinked rubber composition.

Using this uncrosslinked rubber composition, a flat belt of Example 5-1 having the same structure as Embodiment 3 in which the inner rubber layer was formed such that the grain direction was the belt width direction was produced.

For the V-ribbed belt of Example 5-1, the belt length is 1118 mm, the belt width is 10 mm, and the belt thickness is 2.8 mm. In addition, the adhesive rubber layer and the outer rubber layer are formed of a rubber composition that does not contain cellulose microfibers and short fibers, and the core thread is formed of a twisted polyester fiber that has been 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 cellulose microfibers was 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 microfibers was 5 parts by mass relative to 100 parts by mass of the rubber component.

<Example 5-4>

A flat belt of Example 5-4 was 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>

A flat belt of Example 5-5 was produced in the same manner as in Example 5-1 except that the content of cellulose microfibers was 15 parts by mass relative to 100 parts by mass of the rubber component.

<Example 5-6>

A flat belt of Example 5-6 was produced in the same manner as in Example 5-1 except that the content of cellulose microfibers was 25 parts by mass relative 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 microfibers.

<Comparative example 5-2>

Comparative Example 5-2 was produced in the same manner as in Example 5-1, except that cellulose microfibers were not contained in the rubber composition forming the inner rubber layer and 5 parts by mass of nylon short fibers were included with respect to 100 parts by mass of the rubber component. flat belt.

[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, fiber The maximum and minimum diameters.

<Evaluation of friction and wear characteristics with running test>

FIG. 20 shows a pulley design of a belt running tester 170 for evaluating friction and wear characteristics.

The belt running tester 170 for evaluating friction and wear characteristics has a pulley diameter The driving flat pulley 171 that is 120mm, the first driven flat pulley 172 that is arranged on the pulley diameter above it is 120mm, the pulley diameter that is arranged on the right side of the middle position of their up and down direction Be the second driven flat wheel 173 of 50mm. The second driven flat pulley 173 is movable left and right so as to be able to bear an axial load (self-weight DW) and apply tension to the flat belt C.

Each flat belt C of Example 5-1 to Example 5-6 and Comparative Example 5-1 to Comparative Example 5-2 was wound around the drive flat wheel 171 of a belt running tester 170 for evaluating friction and wear characteristics. , Between the first and second driven flat wheels 72 and 73, the second driven flat wheel 173 bears an axial load of 98N to the right and applies tension to the flat belt C, and, on the first driven flat wheel 172 A rotational load of 8.8 kW was applied to the belt, and the driving flat pulley 171 was rotated at a rotational speed of 4800 rpm at an ambient temperature of 120° C. to run the belt. Then, 24 hours after the start of operation, the belt was stopped, and the friction coefficient of the inner rubber layer surface after the belt operation was obtained by the same method as Test Evaluation 1 using the friction coefficient measuring device 140 shown in FIG. 17 . In addition, as the test pulley 141, a pulley diameter of 65mm flat wheels.

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

Then, visually observe the running surfaces of the driving flat pulley 171, the first and second driven flat pulleys 72, 73 after the belt has been running for 24 hours, and evaluate the surface state sensory. , to determine the numerical value of the adhesive wear occurrence index.

In the case of scum-like substances with sticky erasable rubber attached: 100

In the presence of powdery deposits: 50,

In the case of no attachment: 0

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

<Abrasion Resistance Evaluation Tape Running Test>

Figure 21 shows the pulley design of the belt running tester 180 used to evaluate wear resistance.

The belt running tester 180 for evaluating wear resistance has a pulley diameter A driving flat wheel 181 with a diameter of 100 mm and a driven flat wheel 182 with a pulley diameter of 100 mm arranged on its left side. The driving flat pulley 181 is movable left and right so as to be able to bear an axial load (self-weight DW) and apply tension to the flat belt C.

For each of the flat belts C of Example 5-1 to Example 5-6 and Comparative Example 5-1 to Comparative Example 5-2, after measuring the mass of the belt, it was wound on a belt for evaluation of wear resistance. Between the driving flat wheel 181 and the driven flat wheel 182 of the running test machine 180, the driving flat wheel 181 bears an axial load of 300N to the right, applies tension to the flat belt C, and bears 12N on the driven flat wheel 182. With a rotation torque of m, the drive flat pulley 181 is rotated at 2,000 rpm at an ambient temperature of 100° C. to run the belt. Then, 24 hours after the start of the operation, the belt was stopped, the belt mass of the flat belt C was measured, and the mass loss was obtained to calculate the percentage of the mass loss of Comparative Example 5-1.

(test evaluation results)

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

<Average fiber diameter, fiber diameter distribution>

From this, it can be seen that the distribution of the fiber diameters of the cellulose ultrafine fibers contained in the rubber composition forming the inner rubber layer of each of the flat belts in Examples 5-1 to 5-6 is wide.

<Friction and wear characteristics>

-Friction Coefficient-

The friction coefficient of the belt of Comparative Example 5-1 after running for 24 hours was 0.85, while that of Example 5-1 and Example 5-2 was 0.85 similarly, and the cellulose microfibers of the rubber component were 100 parts by mass The content of is about 1 to 3 parts by mass, and does not change the coefficient of friction. If the content of cellulose ultrafine fibers is further increased (Example 5-3 to Example 5-6), the coefficient of friction will be reduced, and it is 0.6 at 25 parts by mass (Example 5-6).

In addition, in the case of Comparative Example 5-2 in which 5 parts by mass of nylon staple fibers were blended, the coefficient of friction was 0.75, which was the same as in Example 5-4 in which the content of cellulose ultrafine fibers was 10 parts by mass.

Comparing the coefficient of friction after 500 hours of belt operation with the friction coefficient after 24 hours of belt operation, in Comparative Example 5-1 and Comparative Example 5-2, they decreased by 0.35 and 0.25 in order, whereas in Example 5 -1 to Examples 5-6, the maximum decrease was 0.15 (Examples 5-1 and 2-2). It can be seen that if the content of cellulose microfibers increases, the amount of reduction is smaller, and if it contains more than 10 parts by mass (Example 5-4 to Example 5-6), the belt after 24 hours after operation and the belt The coefficient of friction after running for 500 hours was the same value.

From this, it can be seen that forming the inner rubber layer with a rubber composition containing cellulose microfibers can provide a flat belt with a small temporal change in the coefficient of friction.

-Adhesive wear occurrence index-

The adhesive wear occurrence index of Comparative Example 5-1 and Comparative Example 5-2 was the evaluation value of 100 and 90. In contrast, in the case of using a rubber composition containing cellulose ultrafine fibers, even with the smallest content (1 parts by mass) of Example 5-1, the adhesive wear occurrence index was also 45, which shows that it has been significantly improved. Can further improve the occurrence index of adhesive wear by increasing the content, in the embodiment 5-6 containing 25 parts by mass of cellulose microfibers, the evaluation value is 10 (the attachments on the belt surface are less, and the adhesiveness is lower There are more powdery substances).

In the case of Comparative Example 5-2 containing nylon staple fibers, compared with Comparative Example 5-1, it was improved but not remarkable.

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

<Wear resistance>

The evaluation value of the wear resistance of Comparative Example 5-1 and Comparative Example 5-2 was 100, in contrast, the content of cellulose ultrafine fiber is 1 mass part of Example 5-1 improved to 65, can be further improved by Increase the content to further improve the evaluation value. Among them, when the content of cellulose ultrafine fibers is in the range of 3 to 25 parts by mass (Example 5-2 to Example 5-6), the evaluation value is 50 or 45, and there is an increase in the content of cellulose ultrafine fibers. However, the wear resistance improvement tends to be saturated.

[Embodiment 4]

(toothed belt B)

FIG. 22 shows a toothed belt B according to the fourth embodiment.

The toothed belt B according to Embodiment 4 includes an endless toothed belt main body 310 formed of a rubber composition. The toothed belt main body 310 has a flat belt-shaped base portion 311 a and a plurality of teeth portions 311 b integrally provided at intervals along the belt length direction at a fixed pitch on one side, that is, an inner peripheral surface thereof. On the toothed belt main body 310 , a tooth side reinforcing cloth 312 is attached so as to cover the tooth side surface. In addition, a core wire 313 is buried on the inner peripheral side of the base portion 311 a of the toothed belt main body 310 so as to form a helix having a pitch in the belt width direction. The toothed belt B according to Embodiment 4 is suitably used as a power transmission member of, for example, a belt transmission of a machine tool or the like, particularly a belt transmission of a machine tool whose operation time is about 3 to 120 hours per year. The toothed belt B according to Embodiment 4 has, for example, a belt length of 500 to 3000 mm, a belt width of 10 to 200 mm, and a belt thickness of 3 to 20 mm. In addition, for the tooth part 311b, for example, the width is 0.63-16.46 mm, the height is 0.37-9.6 mm, and the tooth pitch is 1.0-31.75 mm.

The teeth portion 311b of the toothed belt main body 310 may be trapezoidal teeth with trapezoidal sides, semicircular round teeth, or other shapes. The tooth portion 311b may be formed to extend in the belt width direction, or may be a helical tooth formed to extend in a direction oblique to the belt width direction.

The toothed belt main body 310 is formed of a rubber composition obtained by adding cellulose-based microfibers with a fiber diameter distribution range of 50 to 500 nm to the rubber component and kneading various rubber compounds. The uncrosslinked rubber composition is heated and pressurized and crosslinked with a crosslinking agent. As described above, since the rubber composition forming the toothed belt main body 310 contains cellulose-based ultrafine fibers whose fiber diameters range from 50 to 500 nm, the durability of the toothed belt B can be improved. Here, "ultrafine fibers" in the present application refer to fibers having a fiber diameter of 1.0 μm or less.

As the rubber component of the rubber composition forming the toothed belt main body 310, for example, hydrogenated acrylonitrile rubber (H-HBR), hydrogenated acrylonitrile rubber (H-HBR) reinforced with an unsaturated carboxylic acid metal salt, ethylene- Ethylene-α-olefin elastomers such as propylene copolymer (EPR), ethylene-propylene-diene terpolymer (EPDM), ethylene-octene copolymer, ethylene-butene copolymer, neoprene rubber (CR) and Chlorosulfonated polyethylene rubber (CSM), etc. The rubber component of the rubber composition constituting the toothed belt main body 310 is preferably one or a mixture of two or more rubbers.

In the H-HBR reinforced with an unsaturated carboxylic acid metal salt, 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.

Cellulosic ultrafine fibers are fiber materials based on cellulose ultrafine fibers composed of a skeleton component of plant cell walls obtained by finely dismantling plant fibers. Examples of raw material plants for cellulose-based ultrafine fibers include wood, bamboo, rice (straw), potatoes, sugar cane (bagasse), aquatic plants, and seaweed. Among them, wood is preferable.

The cellulose-based microfibers may be cellulose microfibers themselves, or hydrophobized cellulose microfibers that have been hydrophobized. In addition, as cellulose-based ultrafine fibers, cellulose ultrafine fibers themselves and hydrophobized cellulose ultrafine fibers may be used together. From the standpoint of dispersibility, the cellulose-based ultrafine fibers preferably include hydrophobized cellulose ultrafine fibers. Examples of the hydrophobized cellulose ultrafine fibers include cellulose ultrafine fibers in which a part or all of the hydroxyl groups of cellulose are substituted with hydrophobic groups, and cellulose ultrafine fibers subjected to a hydrophobizing surface treatment using a surface treatment agent.

As hydrophobization for obtaining cellulose microfibers in which a part or all of the hydroxyl groups of cellulose are replaced with hydrophobic groups, for example, esterification (acylation) (alkyl esterification, complex esterification, β- Keto esterification, etc.), alkylation, tosylation, epoxidation, arylation, etc. Among them, esterification is preferable. Specifically, esterified hydrophobized cellulose superfine fibers can be obtained by passing part or all of the hydroxyl groups of cellulose through carboxylic acids such as acetic acid, anhydrous acetic acid, propionic acid, butyric acid, or their halides (especially chlorides). Acylated cellulose microfiber. As a surface treatment agent for obtaining the cellulose ultrafine fiber which surface-treated to hydrophobize using a surface treatment agent, a silane coupling agent etc. are mentioned, for example.

From the viewpoint of improving the durability of the toothed belt B, the cellulose-based ultrafine fibers preferably have a wide distribution of fiber diameters, and the distribution range of fiber diameters includes 50 to 500 nm. The lower limit of the distribution of the fiber diameters is preferably 20 nm or less, more preferably 10 nm or less, from the above point of view. From the same viewpoint, the upper limit is preferably 700 nm or more, and more preferably 1 μm or more. The distribution range of the fiber diameter of the cellulose-based ultrafine fibers is preferably 20 nm to 700 mm, more preferably 10 nm to 1 μm.

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

After the sample of the rubber composition constituting the toothed belt main body 310 was frozen and pulverized, its cross section was observed with a transmission electron microscope (TEM), and 50 cellulose-based ultrafine fibers were arbitrarily selected to measure the fiber diameter, and based on the measurement results, the The fiber diameter distribution of cellulosic microfibers. In addition, the average of the fiber diameters of the 50 arbitrarily selected cellulose-based ultrafine fibers was determined as the average fiber diameter of the cellulose-based ultrafine fibers.

Cellulosic microfibers may be high-aspect-ratio cellulose microfibers produced by mechanical defibration, or needle-like crystals produced by chemical defibration. Among them, it is preferable to manufacture by a mechanical defibrating method. In addition, as the cellulose-based ultrafine fibers, cellulose-based ultrafine fibers produced by a mechanical defibrating method and cellulose-based ultrafine fibers produced by a chemical defibrating method may be used together. Examples of the defibrating apparatus used in the mechanical defibrating method include kneaders such as twin-screw kneaders, high-pressure homogenizers, grinders, sand mills, and the like. As the treatment used in the chemical defibrating method, for example, acid hydrolysis treatment and the like can be cited.

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

Examples of the rubber compounding agent include reinforcing materials, processing aids, vulcanization accelerators, plasticizers, crosslinking auxiliary agents, crosslinking agents, vulcanization accelerators, antiaging agents, and the like.

As a reinforcing material, among carbon blacks, for example, furnace blacks such as channel black, SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, N-234, etc., FT, MT and other thermal carbon black, acetylene carbon black, etc. Silica can also be mentioned as a reinforcing material. The reinforcing material is preferably one or more than two of them. 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 processing aids include stearic acid, polyethylene wax, metal salts of fatty acids, and the like. Processing aids are preferably one or more of them. 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 accelerator include metal oxides such as zinc oxide (zinc white) and magnesium oxide, metal carbonates, fatty acids and derivatives thereof. The vulcanization accelerator is preferably one or more of them. The content of the vulcanization accelerator may be, for example, 3 to 7 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

Examples of plasticizers include dialkyl phthalates such as dibutyl phthalate (DBP) and dioctyl phthalate (DOP), and dioctyl adipate (DOA). Dialkyl esters, dialkyl sebacate such as dioctyl sebacate (DOS), and the like. Plasticizers are preferably one or more of them. The content of the plasticizer may be, for example, 0.1 to 40 parts by mass relative to 100 parts by mass of the rubber component.

Examples of the auxiliary crosslinking agent include liquid rubber such as liquid NBR, and the like. The assistant crosslinking agent is preferably one kind or two or more kinds. The content of the auxiliary crosslinking agent may be, for example, 3 to 7 parts by mass relative to 100 parts by mass of the rubber component.

Examples of the crosslinking agent include sulfur and organic peroxides. As a crosslinking agent, sulfur may be added, an organic peroxide may be added, or both may be used in combination. The amount of the crosslinking agent may be, for example, 1 to 5 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition in the case of sulfur, or 1 to 5 parts by mass in the case of organic peroxides with respect to the rubber composition 100 parts by mass of the rubber component may be, for example, 1 to 5 parts by mass.

As the vulcanization accelerator, for example, thiurams (such as TETD, TT, TRA, etc.), thiazoles (such as MBT, MBTS, etc.), sulfenamides (such as CZ, etc.), dithiocarbamates (such as BZ-P, etc.) and so on. The vulcanization accelerator is preferably one or more of them. The content of the vulcanization accelerator may be, for example, 2 to 5 parts by mass relative to 100 parts by mass of the rubber component of the rubber composition.

As an antiaging agent, an amine type antiaging agent, a diamine type antiaging agent, a phenol type antiaging agent etc. are mentioned, for example. The anti-aging agent is preferably one or two or more of them. The content of the antiaging agent may be, for example, 0.1 to 5 parts by mass with respect to 100 parts by mass of the rubber component.

In addition, short fibers having a fiber diameter of 10 μm or more may be contained in the rubber composition forming the toothed belt main body 310 .

The tooth portion side reinforcing cloth 312 can be made of, for example, a fabric such as woven, knitted, or nonwoven fabric made of cotton, polyamide fiber, polyester fiber, aramid fiber, or the like. The tooth side reinforcement cloth 312 preferably has stretchability. The thickness of the tooth portion side reinforcing cloth 312 is, for example, 0.3 to 2.0 mm. A bonding process for bonding to the toothed belt main body 310 is performed on the tooth portion side reinforcing cloth 312 .

The core wire 313 is constituted by a twisted yarn formed of glass fiber, aramid fiber, polyamide fiber, polyester fiber, or the like. The diameter of the core wire 313 may be, for example, 0.5-2.5 mm, and the dimension between the centers of core wires adjacent to each other in the cross section may be, for example, 0.05-0.20 mm. The core wire 313 is subjected to an adhesive treatment for providing adhesiveness to the toothed belt main body 310 .

According to the toothed belt B according to Embodiment 4 having the above structure, the rubber composition for forming the toothed belt main body 310 including the base portion 311a and the tooth portion 311b contains a cellulose-based superfiber whose fiber diameter distribution range includes 50 to 500 nm. Therefore, an excellent reinforcing effect can be obtained, and in particular, chipping of the tooth portion 311b can be suppressed, and excellent oil resistance can be obtained, and as a result, high durability can be obtained.

(Manufacturing method of toothed belt B)

A method of manufacturing the toothed belt B according to Embodiment 4 will be described based on FIGS. 23 to 26 .

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

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

The manufacturing method of the toothed belt according to Embodiment 4 includes a material preparation step, a molding step, a crosslinking step, and a final processing step.

<Material preparation process>

- Uncrosslinked rubber sheet 311' for base and teeth -

First, cellulose-based microfibers are put into the masticated rubber component, kneaded, and dispersed.

Among them, the method of dispersing the cellulose microfibers as the rubber component, for example, includes the following method: putting the dispersion (gel) obtained by dispersing the cellulose microfibers in water into the dispersing method by masticating with an open mill. In the rubber component, the moisture is vaporized while kneading them; the cellulose microfiber obtained by mixing the dispersion (gel) obtained by dispersing the cellulose ultrafine fiber in water with the rubber latex and vaporizing the water / The masterbatch of rubber is put into the rubber component of mastication; the cellulose-based ultra-fine fiber obtained by mixing the dispersion liquid in which the cellulose-based ultra-fine fiber is dispersed in the solvent and the solution in which the rubber component is dissolved in the solvent is vaporized. The fine fiber/rubber masterbatch is put into the masticated rubber component; the dispersion (gel) in which cellulose-based ultrafine fibers are dispersed in water is freeze-dried and pulverized, and then put into the masticated rubber component; and the hydrophobic The cellulose-based microfibers are put into the masticated rubber component.

Then, while kneading the rubber component and cellulose microfibers, various rubber compounding ingredients were added and kneading was continued.

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

-Reinforcement cloth on tooth side 312'-

Adhesion processing is performed on the tooth portion side reinforcing cloth 312'. Specifically, an RFL bonding process of dipping in an RFL aqueous solution and heating is performed on the tooth portion side reinforcing cloth 312'. In addition, before the RFL bonding treatment, base bonding treatment of immersing in a base bonding treatment liquid and heating is performed as needed. In addition, after the RFL bonding treatment, an impregnated rubber paste bonding process of dipping and drying the rubber paste and/or a coated rubber paste bonding process of applying a rubber paste to the surface of the toothed belt main body 310 side and drying it are performed after the RFL bonding process. deal with.

Then, both ends of the adhesive-treated tooth portion side reinforcing cloth 312' are joined to form a cylindrical shape.

-core wire 313'-

Bonding treatment is performed on the core wire 313'. Specifically, the core wire 313' is subjected to RFL bonding treatment in which the core wire 313' is dipped in a resorcinol-formalin-latex aqueous solution (hereinafter referred to as "RFL aqueous solution") and heated. In addition, before the RFL bonding treatment, a base bonding treatment of dipping in a base bonding treatment liquid and heating and/or a rubber paste bonding treatment of dipping in a rubber paste and drying after the RFL bonding treatment are performed as needed.

<Molding process>

As shown in FIG. 24 , the outer circumference of the belt molding die 320 is covered with a cylindrical tooth portion side reinforcing cloth 312 ′, the core wire 313 ′ is wound spirally thereon, and the uncrosslinked rubber sheet 311 is wound thereon. '. At this time, the laminated molded body B' is formed on the belt molding die 320. In addition, the uncrosslinked rubber sheet 311' may be used such that the grain direction corresponds to the belt length direction, or may be used such that the grain direction corresponds to the belt width direction.

<Crosslinking process>

As shown in FIG. 25 , after the release paper 322 is wound around the outer periphery of the laminated molded body B', a rubber sleeve 323 is covered on it, and it is arranged in a vulcanization tank to be sealed, and the autoclave is filled with high-temperature, High-pressure steam to maintain the prescribed molding time. At this time, the uncrosslinked rubber sheet of the laminated molded body B′ presses the tooth portion side reinforcing cloth 312 to flow, flows into the tooth portion forming groove 321 of the belt molding die 320, and is crosslinked and bonded to the tooth portion side reinforcing cloth 312. ' and the core wire 313' are compounded and integrated, and finally, as shown in Figure 26, a cylindrical strip S is formed. In addition, the forming temperature of the strip S may be, for example, 100-180° C., the forming pressure may be, for example, 0.5-2.0 MPa, and the forming time may be, for example, 10-60 minutes.

<Final Processing Process>

The inside of the vulcanization tank is decompressed, the airtightness is released, the strip plate S formed between the strip molding die 320 and the rubber sleeve 323 is taken out, released from the mold, the back side is ground to adjust the thickness, and then cut to a predetermined width. Formed into a wheel shape to manufacture a toothed belt B.

[Embodiment 5]

(toothed belt B)

The appearance structure of the toothed belt B according to the fifth embodiment is the same as that of the fourth embodiment, so it will be described below based on FIG. 22 .

In the toothed belt B according to Embodiment 5, the rubber composition forming the base portion 311 a of the toothed belt main body 310 contains cellulose-based ultrafine fibers whose fiber diameter distribution range includes 50 to 500 nm. On the other hand, the rubber composition forming the tooth portion 311b does not contain cellulose-based ultrafine fibers. In addition, the rubber composition forming the tooth portion 311b may contain cellulose-based ultrafine fibers whose fiber diameter distribution range does not include 50 to 500 nm.

Other structures are the same as those in Embodiment 4.

According to the toothed belt B according to Embodiment 5 having the above-mentioned structure, the rubber composition forming the base portion 311a contains cellulose-based ultrafine fibers whose fiber diameters range from 50 to 500 nm, so that an excellent reinforcing effect can be obtained. In addition, excellent oil resistance can be obtained, and as a result, high durability can be obtained.

(Manufacturing method of 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, a cellulose-based ultrafine fiber having a fiber diameter distribution range of 50 to 500 nm is produced for the base. The uncrosslinked rubber sheet 311a'. In addition, various rubber compounding agents are added to the rubber component, and cellulose-based microfibers obtained by kneading with a kneader such as a kneader or a Banbury mixer are used. The distribution range of the fiber diameter does not include 50 to 500 nm The non-crosslinked rubber composition for the tooth part formed into the shape of the tooth part forming groove 321 of the belt molding die 320 is made of the non-crosslinked rubber 311b' for the tooth part.

Then, in the molding process, as shown in FIG. 27 , after covering the outer periphery of the belt molding die 320 with a cylindrical tooth portion side reinforcing cloth 312 ′ and setting it along the tooth portion forming groove 321 , as shown in FIG. Each tooth portion forming groove 321 is fitted with an uncrosslinked rubber 311b' for the tooth portion, as shown in FIG. The rubber sheet 311a' is cross-linked to form a laminated molded body B'. In the cross-linking step, the non-cross-linked rubber 311b' for the teeth and the non-cross-linked rubber sheet 311a' for the base of the laminated molded body B' are cross-linked, and they are combined with the tooth side reinforcement cloth. 312 ′ and the core wire 313 ′ are composited and integrated, and finally, a cylindrical strip S similar to that in FIG. 26 of Embodiment 4 is molded.

Other methods are the same as in Embodiment 4.

[Embodiment 6]

(toothed belt B)

The appearance structure of the toothed belt B according to the sixth embodiment is the same as that of the fourth embodiment, so it will be described below based on FIG. 22 .

In the toothed belt B according to Embodiment 6, the rubber composition forming the tooth portion 311b of the toothed belt main body 310 contains cellulose-based ultrafine fibers whose fiber diameter distribution range includes 50 to 500 nm. On the other hand, the rubber composition forming the base portion 311a does not contain cellulose-based ultrafine fibers. In addition, the rubber composition forming the base portion 311a may contain cellulose-based ultrafine fibers whose fiber diameter distribution range does not include 50 to 500 nm.

Other structures are the same as those in Embodiment 4.

According to the toothed belt B according to Embodiment 6 having the above-mentioned structure, the rubber composition forming the tooth portion 311b contains cellulose-based ultrafine fibers whose fiber diameters are distributed in a range of 50 to 500 nm, so that an excellent reinforcing effect can be obtained. , in particular, chipping of the tooth portion 311b can be suppressed, and excellent oil resistance can be obtained, and as a result, high durability can be obtained.

(Manufacturing method of 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, cellulose-based ultrafine fibers having a fiber diameter distribution range of 50 to 500 nm are used for the teeth. The uncrosslinked rubber composition is kneaded, and it is made into the uncrosslinked rubber 311b' for teeth formed into the shape of the teeth forming groove 321 of the belt molding die 320 . In addition, various rubber compounding ingredients are added to the rubber component, and the uncrosslinked rubber composition not containing cellulose-based ultrafine fibers obtained by kneading with a kneader such as a kneader or a Banbury mixer is calender-molded etc. into a sheet shape to produce an uncrosslinked rubber sheet 311a' for the base.

Then, in the molding process, as in FIG. 27 of Embodiment 5, after covering the outer periphery of the belt molding die 320 with the cylindrical tooth portion side reinforcing cloth 312 ′ and setting it along the tooth portion forming groove 321 , the same as in FIG. 28 . , insert the non-crosslinked rubber 311b' for the teeth into each tooth forming groove 321, and wind the core wire 313' helically thereon as in FIG. 29, and then wind the base for the base thereon. The uncrosslinked rubber sheet 311a', thereby forming a laminated molded body B'. In the cross-linking step, the non-cross-linked rubber 311b' for the teeth and the non-cross-linked rubber sheet 311a' for the base of the laminated molded body B' are cross-linked, and they are combined with the tooth side reinforcement cloth. 312 ′ and the core wire 313 ′ are composited and integrated, and finally, a cylindrical strip S similar to that in FIG. 26 of Embodiment 4 is molded.

Other methods are the same as in Embodiment 4.

[Embodiment 7]

(toothed belt B)

The outer appearance structure of the toothed belt B according to the seventh embodiment is the same as that of the fourth embodiment, so it will be described below based on FIG. 22 .

In the toothed belt B according to the seventh embodiment, the tooth portion side reinforcing cloth 312 is subjected to the RFL bonding treatment of immersing in the RFL aqueous solution and heating. Thereby, as shown in FIG. 30 , the tooth portion side reinforcing cloth 312 is bonded to the toothed belt main body 310 via the RFL bonding layer 314 formed by the RFL bonding process. In addition, prior to the RFL bonding treatment, a base bonding treatment is performed by dipping in a base bonding treatment liquid made of a base bonding treatment agent such as epoxy resin or isocyanate resin (blocked isocyanate) and heated. It is composed of a solution dissolved in a solvent such as toluene or a dispersion liquid dispersed in water, and a base adhesive layer is preferably provided under the RFL adhesive layer 314 . In addition, after the RFL bonding treatment, the impregnated rubber paste bonding process of dipping and drying the rubber paste and the coating rubber paste bonding process of applying the rubber paste to the surface of the toothed belt main body 310 side and drying it may be performed. For one or two types of rubber paste bonding treatment, a rubber paste bonding layer is provided on the RFL bonding layer 314 .

The RFL adhesive layer 314 is formed of a solid component contained in an RFL aqueous solution, and contains a resorcinol-formalin resin (RF resin) and a rubber component derived from rubber latex. In addition, the RFL adhesive layer 314 contains cellulose-based ultrafine fibers whose fiber diameter distribution range includes 50 to 500 nm. The cellulose-based ultrafine fibers contained in the RFL adhesive layer 314 have the same structure as the cellulose-based microfibers contained in the toothed belt main body 310 according to the fourth embodiment. As described above, the RFL adhesive layer 314 contains cellulose-based microfibers whose fiber diameter distribution range includes 50 to 500 nm, so that high adhesive force of the tooth side reinforcing cloth 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, that is, they are randomly oriented.

The content of the cellulose-based microfibers in the RFL adhesive layer 314 is preferably 0.5% by mass or more, more preferably 1.0% by mass, from the viewpoint that the tooth side reinforcing cloth 312 has high adhesiveness to the toothed belt main body 310 Above, more preferably 2.0% by mass or more, and preferably 12% by mass or less, more preferably 10% by mass or less, even more preferably 8% by mass or less.

The content of cellulose-based microfibers in the RFL adhesive layer 314 relative 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 preferably 30 parts by mass or less, more preferably 20 parts by mass or less, further preferably 10 parts by mass or less.

In addition, it is preferable not to include short fibers having a fiber diameter of 10 μm or more in the RFL adhesive layer 314, but the short fibers may be included within a range that does not affect the adhesiveness of the tooth side reinforcement cloth 312 to the toothed belt main body 310. .

In addition, the rubber composition forming the base portion 311a of the toothed belt main body 310 may contain cellulose-based microfibers similarly to Embodiments 4 and 5, or may not contain cellulose-based microfibers. The rubber composition forming the tooth portion 311b of the toothed belt main body 310 may contain cellulose-based microfibers similarly to Embodiments 4 and 6, or may not contain cellulose-based microfibers.

Other structures are the same as those in Embodiment 4.

According to the toothed belt B according to Embodiment 7 having the above structure, the RFL adhesive layer 314 provided between the tooth portion side reinforcement cloth 312 and the toothed belt main body 310 contains cellulose whose fiber diameter distribution range includes 50 to 500 nm. Therefore, it is possible to obtain a high adhesive force of the tooth portion side reinforcing cloth 312 to the toothed belt main body 310, and to obtain its excellent reinforcing effect. In particular, it is possible to suppress the defect of the tooth portion 311b. , can obtain higher durability.

(Manufacturing method of 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 produced, the tooth portion side reinforcing cloth 312' is bonded. Specifically, an RFL bonding process of dipping in an RFL aqueous solution and heating is performed on the tooth portion side reinforcing cloth 312'. In addition, before the RFL bonding treatment, it is preferable to perform the base bonding treatment of immersing in the base bonding treatment liquid and heating. In addition, after the RFL bonding treatment, one of an impregnated rubber paste bonding process of dipping and drying a rubber paste and a coating rubber paste bonding process of applying a rubber paste to the surface of the toothed belt main body 310 side and drying it may be performed after the RFL bonding process. One or two kinds of rubber paste bonding treatment.

"Substrate Adhesive Treatment"

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

The immersion time in the substrate bonding treatment liquid may be, for example, 1 to 3 seconds. The heating temperature (furnace temperature) after dipping in the base bonding treatment liquid is, for example, 200 to 250°C. The heating time (residence time in the furnace) may be, for example, 1 to 3 minutes. The number of substrate bonding treatments may be one time, or two or more times. The base adhesive treatment agent is adhered to the tooth side reinforcing cloth 312', however, the amount of adhesion (coating amount) is based on the mass of the fiber material forming the tooth side reinforcing cloth 312', for example, it may be 0.5 to 8 mass %.

《RFL Bonding Treatment》

The RFL aqueous solution is an aqueous solution in which rubber latex and a dispersion (gel) in which cellulose microfibers are dispersed in water is mixed with an initial condensate of resorcinol and formaldehyde. The liquid temperature of the RFL aqueous solution may be, for example, 20 to 30°C.

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

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

The immersion time in the RFL aqueous solution may be, for example, 1 to 3 seconds. The heating temperature (furnace temperature) after immersion in RFL aqueous solution can be 100-180, for example. The heating time (residence time in the furnace) may be, for example, 1 to 5 minutes. The number of times of RFL bonding treatment may be one time, or may be two or more times. The RFL adhesive layer 314 is attached to the tooth side reinforcing cloth 312', however, the amount of the adhesion (coating amount) is based on the mass of the fiber material forming the tooth side reinforcing cloth 312', and may be, for example, 2 to 5% by mass. .

Other methods are the same as in Embodiment 4.

[Embodiment 8]

The external appearance structure of the toothed belt B according to the eighth embodiment is the same as that of the fourth embodiment, so it will be described below with reference to FIG. 22 .

In the toothed belt B according to the eighth embodiment, the tooth portion side reinforcing cloth 312 is subjected to RFL bonding treatment of dipping in an RFL aqueous solution and heating, dipping in rubber paste and drying, and applying rubber paste bonding treatment to the tooth profile. One or both of rubber paste bonding treatments in which rubber paste is applied to the surface of the belt main body 310 side and dried. Thus, as shown in FIG. 31 , the tooth portion side reinforcing cloth 312 is bonded to the toothed belt main body 310 via the RFL adhesive layer 314 formed by the RFL adhesive process and the rubber paste adhesive layer 315 formed by the rubber paste adhesive process. combine. In addition, it is preferable to perform base bonding treatment by immersing in a base bonding treatment liquid and heating before the RFL bonding treatment, and to provide a base bonding layer under the RFL bonding layer 314, wherein the base bonding treatment liquid is made of epoxy resin. It consists of a solution in which a substrate adhesive treatment agent such as resin and isocyanate resin (blocked isocyanate) is dissolved in a solvent such as toluene, or a decomposed liquid dispersed in water.

Like Embodiment 4, the RFL adhesive layer 314 may contain cellulose-based ultrafine fibers whose fiber diameter distribution range includes 50 to 500 nm, or may not contain cellulose-based ultrafine fibers.

The rubber paste adhesive layer 315 is formed by the rubber composition of the solid content contained in the rubber paste, and the rubber composition used to form the rubber paste adhesive layer 315 includes a fiber diameter distribution range of 50 to 500 nm in the rubber component. The uncrosslinked rubber composition is made of cellulose-based ultrafine fibers mixed with various rubber compounding ingredients, heated and pressurized, and crosslinked with a crosslinking agent. As described above, the rubber paste adhesive layer 315 contains cellulose-based ultrafine fibers whose fiber diameters range from 50 to 500 nm, so that high adhesive force of the tooth side reinforcing cloth 312 to the toothed belt main body 310 can be obtained.

As the rubber component of the rubber composition forming the rubber paste adhesive layer 315, for example, hydrogenated acrylonitrile rubber (H-HBR), unsaturated carboxylic acid metal salt reinforced hydrogenated acrylonitrile rubber (H-HBR), ethylene- Ethylene-α-olefin elastomers such as propylene copolymer (EPR), ethylene-propylene-diene terpolymer (EPDM), ethylene-octene copolymer, ethylene-butene copolymer, neoprene rubber (CR) and Chlorosulfonated polyethylene rubber (CSM), etc. The rubber component of the rubber composition forming the toothed belt main body 310 is preferably one or a mixture of two or more rubbers. The rubber component of the rubber composition forming the rubber paste adhesive layer 315 may be the same as or different from the rubber component of the rubber composition forming the toothed belt main body 310 .

The cellulose-based microfibers contained in the rubber composition forming the rubber paste adhesive layer 315 have the same structure as the cellulose-based microfibers contained in the toothed belt main body 310 according to the fourth embodiment. In the rubber paste adhesive layer 315, the cellulose-based ultrafine fibers are not oriented in a specific direction, but are randomly oriented.

Regarding the content of the cellulose-based microfibers in the rubber paste adhesive layer 315, from the viewpoint that the tooth side reinforcing cloth 312 has high adhesiveness to the toothed belt main body 310, with respect to 100 parts by mass of the rubber component, Preferably 1 part by mass or more, more preferably 3 parts by mass or more, still more preferably 5 parts by mass or more, and preferably 30 parts by mass or less, more preferably 20 parts by mass or less, further preferably 10 parts by mass or less.

Examples of the rubber compounding agent include reinforcing materials, friction coefficient reducing materials, cross-linking agents, anti-aging agents and the like.

As a reinforcing material, among carbon blacks, for example, furnace blacks such as channel black, SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, N-234, etc., FT, MT and other thermal carbon black, acetylene carbon black, etc. Silica can also be mentioned as a reinforcing material. The reinforcing material is preferably one or more than two of them. The content of the reinforcing material is preferably less than that of the rubber composition forming the toothed belt main body 310 , and may be, for example, 10 to 30 parts by mass relative 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 coefficient of friction reducing material is preferably one or more than two of them. The content of the coefficient of friction reducing material may be, for example, 5 to 15 parts by mass relative to 100 parts by mass of the rubber component of the rubber composition.

Examples of the crosslinking agent include sulfur and organic peroxides. As a crosslinking agent, sulfur may be added, an organic peroxide may be added, or both may be used in combination. The amount of the crosslinking agent may be, for example, 0.3 to 5 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition in the case of sulfur, or 0.3 to 5 parts by mass with respect to 100 parts by mass of the rubber component in the case of organic peroxides, with respect to the rubber composition 100 parts by mass of the rubber component may be, for example, 0.3 to 5 parts by mass.

As the vulcanization accelerator, for example, thiurams (such as TETD, TT, TRA, etc.), thiazoles (such as MBT, MBTS, etc.), sulfenamides (such as CZ, etc.), dithiocarbamates (such as BZ-P, etc.) and so on. The vulcanization accelerator is preferably one or more of them. The content of the vulcanization accelerator may be, for example, 1 to 3 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

As an antiaging agent, an amine type antiaging agent, a diamine type antiaging agent, a phenol type antiaging agent etc. are mentioned, for example. The anti-aging agent is preferably one or two or more of them. The content of the antiaging agent may be, for example, 1 to 3 parts by mass with respect to 100 parts by mass of the rubber component.

In addition, in the rubber composition forming the rubber paste adhesive layer 315, it is preferable not to contain short fibers having a fiber diameter of 10 μm or more. The aforementioned short fibers may be included in the range.

In addition, the rubber composition forming the base portion 311a of the toothed belt main body 310 may contain cellulose-based microfibers similarly to Embodiments 4 and 5, or may not contain cellulose-based microfibers. The rubber composition forming the tooth portion 311b of the toothed belt main body 310 may contain cellulose-based microfibers similarly to Embodiments 4 and 6, or may not contain cellulose-based microfibers.

According to the toothed belt B according to Embodiment 8 having the above structure, the rubber paste adhesive layer 315 provided between the tooth portion side reinforcement cloth 312 and the toothed belt main body 310 contains fibers whose fiber diameter distribution range includes 50 to 500 nm. Therefore, it is possible to obtain a high adhesive force of the tooth portion side reinforcing cloth 312 to the toothed belt main body 310, and therefore, an excellent reinforcing effect thereof can be obtained, and in particular, the defect of the tooth portion 311b can be suppressed. , can obtain excellent oil resistance. In addition, since the rubber paste adhesive layer 315 contains cellulose-based ultrafine fibers whose fiber diameters range from 50 to 500 nm, it is possible to impart high wear resistance to the tooth portion side surface. As a result, high durability can be obtained.

(Manufacturing method of toothed belt B)

In the method of manufacturing the toothed belt B according to the eighth embodiment, in the material preparation step, when the tooth portion side reinforcing cloth 312' is produced, the tooth portion side reinforcing cloth 312' is bonded. Specifically, RFL bonding treatment of dipping in an RFL aqueous solution and heating is performed on the tooth portion side reinforcing cloth 312 ′, further, impregnated rubber paste bonding treatment of dipping in rubber paste and drying, and bonding on the toothed belt main body 310 side are performed. One or two kinds of rubber paste bonding treatments in which the surface is coated with rubber paste and dried. In addition, it is preferable to carry out the base bonding treatment of immersing in the base bonding treatment liquid and heating before the RFL bonding treatment.

The substrate bonding process is the same as that of the seventh embodiment.

《RFL Bonding Treatment》

The RFL aqueous solution is an aqueous solution in which rubber latex is mixed with an initial condensate of resorcinol and formaldehyde. In addition, when the RFL adhesive layer 314 contains cellulose-based ultrafine fibers, a dispersion (gel) in which cellulose-based ultrafine fibers are dispersed in water may be contained in the RFL aqueous solution as in Embodiment 7. The liquid temperature of the RFL aqueous solution may be, for example, 20 to 30°C. 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, R/F=1/1 to 1/2. Examples of the rubber latex include vinylpyridine-styrene-butadiene rubber latex (Vp-St-SBR), neoprene rubber latex (CR), chlorosulfonated polyethylene rubber latex (CSM), and the like. The solid content mass ratio of the primary condensate (RF) of resorcinol and formaldehyde to the rubber latex (L) is, for example, RF/L=1/5 to 1/20.

The immersion time in the RFL aqueous solution may be, for example, 1 to 3 seconds. The heating temperature (furnace temperature) after immersion in RFL aqueous solution may be 100-180 degreeC, for example. The heating time (residence time in the furnace) may be, for example, 1 to 5 minutes. The number of times of RFL bonding treatment may be one time, or may be two or more times. The RFL adhesive layer 314 is attached to the tooth side reinforcing cloth 312', however, the amount of the adhesion (coating amount) is based on the mass of the fiber material forming the tooth side reinforcing cloth 312', and may be, for example, 2 to 5% by mass. .

"Rubber Paste Adhesive Treatment"

The rubber paste is a solution obtained by dissolving the uncrosslinked rubber composition before crosslinking of the rubber composition containing cellulose microfibers used to form the rubber paste adhesive layer 315 in a solvent such as toluene. The rubber paste was produced in the following manner.

First, cellulose-based microfibers are put into the masticated rubber component, kneaded, and dispersed.

Among them, as a dispersion method for dispersing cellulose-based ultrafine fibers in the rubber component, for example, the following method can be cited: the dispersion (gel) obtained by dispersing cellulose-based ultrafine fibers in water is put into In the rubber component, the moisture is vaporized while kneading them; the cellulose microfiber obtained by mixing the dispersion (gel) obtained by dispersing the cellulose ultrafine fiber in water with the rubber latex and vaporizing the water / The masterbatch of rubber is put into the rubber component of mastication; the dispersion obtained by dispersing the hydrophobized cellulose ultrafine fiber in the solvent is mixed with the solution in which the rubber component is dissolved in the solvent, and the fiber obtained by vaporizing the solvent The masterbatch of vegan ultrafine fiber/rubber is put into the rubber component of mastication; the dispersion (gel) that disperses the cellulose ultrafine fiber in water is freeze-dried and pulverized, and then put into the rubber component of mastication; And put the hydrophobized cellulose microfiber into the masticated rubber component.

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

Then, this uncrosslinked rubber composition was poured into a solvent, and stirred until a uniform solution was formed to prepare a rubber paste. The liquid temperature of the rubber paste may be, for example, 20 to 30°C.

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

In the case of bonding treatment by dipping rubber paste, the immersion time in the rubber paste may be, for example, 1 to 3 seconds. The drying temperature (oven temperature) after dipping in the rubber paste may be, for example, 50 to 100°C. The drying time (residence time in the oven) may be, for example, 1 to 3 minutes. The frequency of bonding treatment with the impregnated rubber paste can be one time or more than two times. The rubber paste adhesive layer 315 is attached to the tooth side reinforcing cloth 312', but the amount of adhesion (coating amount) is based on the quality of the fiber material forming the tooth side reinforcing cloth 312', for example, it can be 2 to 5 quality%.

In the case of coating rubber paste bonding treatment, the drying temperature (oven temperature) after coating may be, for example, 50 to 100°C. The drying time (residence time in the oven) may be, for example, 1 to 3 minutes. The number of times of applying rubber paste bonding treatment may be one time or more than two times. The rubber paste adhesive layer 315 is adhered to the tooth side reinforcing cloth 312', however, the amount of the adhesive (coating amount) is based on the mass of the fiber material forming the tooth side reinforcing cloth 312'. For example, it may be 2 to 5% by mass.

Other methods are the same as in Embodiment 4.

-Example-

(uncrosslinked rubber composition)

The following rubbers 1 to 7 of the uncrosslinked rubber composition used for forming the main body of the toothed belt and rubbers 8 to 14 of the uncrosslinked rubber composition used for the rubber paste adhesive layer of the tooth side reinforcement cloth were produced. Table 6 and Table 7 show various combinations.

<Rubber 1>

First, prepare a dispersion liquid in which powdered cellulose (manufactured by Nippon Paper Co., Ltd.: KCflock W-GK) is dispersed in toluene, and use a high-pressure homogenizer to collide the dispersion with each other to defibrilate the powdered cellulose into fibers. cellulose microfibers to obtain a dispersion of cellulose microfibers dispersed in toluene. Thus, cellulose microfibers were produced by a mechanical defibration method, and no hydrophobizing treatment was performed.

Then, the dispersion of cellulose microfibers dispersed in toluene was dissolved in toluene with H-HBR (trade name produced by ZEON Corporation of Japan: Zetpol 2020) and added with a plasticizer (trade name produced by DIC Corporation: W-260) is mixed with a solution to vaporize toluene and plasticizer to produce a masterbatch of cellulose microfiber/H-HBR. In addition, the content of each component in the masterbatch was 25% by mass of cellulose-based ultrafine fibers, 25% by mass of the plasticizer, and 50% by mass of H-HBR.

Then, H-HBR was masticated, and a masterbatch was put thereinto and kneaded. The mixing mass ratio of H-HBR and masterbatch is 98:4, when the total amount of H-HBR is 100 parts by mass, the content of cellulose microfiber is 1 part by mass.

Then, H-HBR, cellulose microfibers and plasticizer were kneaded, and FEF carbon black (Tokai Carbon Co., Ltd. Production trade name: SEAST SO), 1 mass part of stearic acid (NOF Corporation production trade name: Stearic Acid Stearic Acid), 5 mass parts of zinc oxide (Kai Kagaku Kogyo) as vulcanization acceleration aid as processing aid The trade name produced by the company: two kinds of zinc oxide), 24 parts by mass of plasticizer, 5 parts by mass of liquid NBR (trade name produced by Japan ZEON company: Nipol 1312), 0.5 parts by mass of NBR as a crosslinking agent Sulfur (trade name: oilSulfur produced by Japan Dry Distillation Industry Co., Ltd.), 2 mass parts of thiuram vulcanization accelerator (trade name: Nocseller TET-G produced by Ouchi Shining Chemical Co., Ltd.) and 2 mass parts of amine ketones Aging agent (trade name: Nocrac224 produced by Ouchi Xinxing Co., Ltd.) was continued to knead to make an uncrosslinked rubber composition. This uncrosslinked rubber composition was referred to as Rubber 1. In addition, regarding the content of the plasticizer in Rubber 1, the total amount contained in the masterbatch and added later was 25 parts by mass with respect to 100 parts by mass of HNBR.

<Rubber 2>

A non-crosslinked rubber composition produced in the same manner as Rubber 1 was used as Rubber 2 except that the content of cellulose ultrafine fibers was 3 parts by mass relative to 100 parts by mass of H-HBR.

<Rubber 3>

A non-crosslinked rubber composition produced in the same manner as Rubber 1 was used as Rubber 3 except that the content of cellulose microfibers was 5 parts by mass relative to 100 parts by mass of H-HBR.

<Rubber 4>

A non-crosslinked rubber composition produced in the same manner as Rubber 1 was used as Rubber 4 except that the content of cellulose ultrafine fibers was 10 parts by mass relative to 100 parts by mass of H-HBR.

<Rubber 5>

A non-crosslinked rubber composition produced in the same manner as Rubber 1 was used as Rubber 5 except that the content of cellulose ultrafine fibers was 15 parts by mass relative to 100 parts by mass of H-HBR.

<Rubber 6>

A non-crosslinked rubber composition prepared in the same manner as Rubber 1 was used as Rubber 6 except that the content of cellulose ultrafine fibers was 25 parts by mass relative to 100 parts by mass of H-HBR.

<Rubber 7>

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 accelerator, 10 parts by mass of plasticizer, 5 parts by mass of liquid NBR as an auxiliary crosslinking agent, 0.5 parts by mass of sulfur as a crosslinking agent, 2 parts by mass of thiurams A vulcanization accelerator and 2 parts by mass of an amine-based antiaging agent were kneaded to prepare an uncrosslinked rubber composition. This uncrosslinked rubber composition was referred to as Rubber 7. Thus, the rubber 7 does not contain cellulose microfibers.

[Table 6]

<Rubber 8>

Strengthen H-HBR (trade name: Zeoforte ZSC 2295 produced by ZEON Corporation of Japan) and H-HBR (trade name: Zetpole 2020 produced by ZEON Corporation of Japan) with zinc methacrylate in such a way that the mixing mass ratio of the former and the latter is 50:50 Mastication, and 20 parts by mass of FEF carbon black (trade name produced by Tokai Carbon Co., Ltd.: SEAST SO) as a reinforcing material relative to 100 parts by mass of the rubber component, and 10 parts by mass of FEF carbon black as a friction coefficient reducing material were respectively dropped into 100 parts by mass of the rubber component. Ultra-high molecular weight polyethylene powder (trade name: mipelonXM-220 produced by Mitsui Chemicals Co., Ltd.), 0.5 parts by mass of sulfur (trade name produced by Japan Dry Distillation Industry Co., Ltd.: oilSulfur) as a crosslinking agent, 2 parts by mass of thiuram vulcanization Accelerator (trade name: Nocseller TET-G produced by Ouchi Shinko Chemical Co., Ltd.) and 2 parts by mass of amine-ketone antiaging agent (trade name: Nocrac224 produced by Ouchi Shinko Co., Ltd.), kneaded to make uncrosslinked rubber combination. This uncrosslinked rubber composition was designated as rubber 8. Thus, the rubber 8 does not contain cellulose microfibers.

<Rubber 9>

Zinc methacrylate-reinforced H-HBR and H-HBR were masticated, and a masterbatch was put thereinto and kneaded. The mixing mass ratio of zinc methacrylate reinforced H-HBR, H-HBR and masterbatch is 50:48:4, when the total amount of H-HBR is 100 parts by mass, the content of cellulose microfiber is 1 mass share.

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

<Rubber 10>

A non-crosslinked rubber composition was prepared as Rubber 10 in the same manner as Rubber 9 except that the content of cellulose microfibers was 3 parts by mass relative to 100 parts by mass of the rubber component.

<Rubber 11>

A non-crosslinked rubber composition was produced as Rubber 11 in the same manner as Rubber 9 except that the content of cellulose microfibers was 5 parts by mass relative to 100 parts by mass of the rubber component.

<Rubber 12>

A non-crosslinked rubber composition was prepared as Rubber 12 in the same manner as Rubber 9 except that the content of cellulose microfibers was 10 parts by mass relative to 100 parts by mass of the rubber component.

<Rubber 13>

A non-crosslinked rubber composition was prepared as Rubber 13 in the same manner as Rubber 9 except that the content of cellulose microfibers was 15 parts by mass relative to 100 parts by mass of the rubber component.

<Rubber 14>

A non-crosslinked rubber composition was prepared as Rubber 14 in the same manner as Rubber 9 except that the content of cellulose microfibers was 25 parts by mass relative to 100 parts by mass of the rubber component.

[Table 7]

(toothed belt for experimental evaluation)

Toothed belts for experimental evaluation of the following Examples 6-1 to 6-13 and Comparative Example 6 (the tooth pitch of the tooth portion is 8 mm, and the belt width is 10 mm) were produced. Table 8 shows the respective structures.

<Example 6-1>

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

As the tooth portion side reinforcing fabric, a woven fabric was used in which aramid fiber (trade name: Technora manufactured by Teijin Corporation) was wound around a polyurethane thread to impart stretchability to the covered yarn as the weft, and nylon twisted yarn as the warp. As the base bonding treatment, the woven fabric of the reinforcing fabric on the tooth side was subjected to a base bonding treatment of dipping in an epoxy resin solution and then heating, and a RFL bonding treatment of dipping in an RFL aqueous solution and then heating. In addition, the woven fabric of the tooth portion side reinforcing fabric subjected to the RFL bonding treatment was repeatedly subjected to the rubber paste impregnated bonding process of immersing in the rubber paste and drying it twice. As the rubber paste, a rubber paste having a solid content concentration of 10% by mass was used in which the rubber 8 not containing cellulose microfibers was dissolved in a toluene solvent. The liquid temperature of the rubber paste is 25°C. The dipping time of the rubber paste was 5 seconds. The drying temperature after dipping the rubber paste was 100° C., and the drying time was 40 seconds.

As the core wire, a glass fiber core wire was 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 cellulose ultrafine fibers was used as the uncrosslinked rubber composition forming the main body of the toothed belt.

<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 cellulose ultrafine fibers was used as the uncrosslinked rubber composition forming the main body of the toothed belt.

<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 cellulose microfibers was used as the uncrosslinked rubber composition forming the main body of the toothed belt.

<Example 6-5>

The toothed belt of Example 6-5 was produced in the same manner as in Example 6-4, except that the rubber paste of rubber 9 containing cellulose microfibers was used for the adhesive treatment of the tooth portion side reinforcement cloth impregnated with the rubber paste.

<Example 6-6>

The toothed belt of Example 6-6 was produced in the same manner as in Example 6-4, except that the rubber paste of rubber 10 containing cellulose microfibers was used for the adhesive treatment of the tooth portion side reinforcement cloth impregnated with the rubber paste.

<Example 6-7>

The toothed belt of Example 6-7 was produced in the same manner as in Example 6-4, except that the rubber paste of rubber 11 containing cellulose microfibers was used for the adhesive treatment of the tooth portion side reinforcing cloth impregnated with the rubber paste.

<Example 6-8>

The toothed belt of Example 6-8 was produced in the same manner as in Example 6-4, except that the rubber paste of rubber 12 containing cellulose microfibers was used for the bonding treatment of the tooth portion side reinforcement cloth impregnated with rubber paste.

<Example 6-9>

The toothed belt of Example 6-9 was produced in the same manner as in Example 6-4, except that the rubber paste of rubber 13 containing cellulose microfibers was used for the adhesive treatment of the tooth portion side reinforcement cloth impregnated with the rubber paste.

<Example 6-10>

The toothed belt of Example 6-10 was produced in the same manner as in Example 6-4, except that the rubber paste of rubber 14 containing cellulose microfibers was used for the adhesive treatment of the tooth portion side reinforcement cloth impregnated with the rubber paste.

<Example 6-11>

The toothed belt of Example 6-11 was produced in the same manner as in Example 6-1 except that the rubber 5 containing cellulose ultrafine fibers was used as the uncrosslinked rubber composition forming the main body of the toothed belt.

<Example 6-12>

The toothed belt of Example 6-12 was produced in the same manner as in Example 6-1 except that the rubber 6 containing cellulose ultrafine fibers was used as the uncrosslinked rubber composition forming the main body of the toothed belt.

<Example 6-13>

As the uncrosslinked rubber composition forming the main body of the toothed belt, except that rubber 7 not containing cellulose microfibers is used and rubber containing cellulose microfibers is used in the impregnated rubber paste bonding treatment of the tooth side reinforcement cloth Except for the rubber paste of 12, the toothed belt of Example 6-13 was produced in the same manner as in Example 6-1.

<Comparative example 6>

As the uncrosslinked rubber composition forming the main body of the toothed belt, except for using rubber 7 not containing cellulose microfibers and using rubber 7 not containing cellulose microfibers in the impregnated rubber paste bonding treatment of the tooth side reinforcement cloth Except for the rubber paste of rubber 8, the toothed belt of Comparative Example 6 was produced in the same manner as in Example 6-1.

[Table 8]

(Test Evaluation Method)

<Average fiber diameter and fiber diameter distribution of cellulose microfibers>

Samples of the rubber compositions of crosslinked rubbers 1 to 6 and rubbers 9 to 14 were collected from the toothed belt main body and the rubber paste adhesive layer of the toothed belts of Examples 6-1 to 6-13, and these rubbers were After the sample of the composition was frozen and pulverized, its cross-section was observed with a scanning electron microscope (SEM), and 50 fibers were randomly selected to measure the fiber diameter, and the average was obtained as the average fiber diameter. In addition, the maximum and minimum values of the fiber diameters among the 50 cellulose ultrafine fibers were obtained.

<with running test>

FIG. 32 shows a pulley design for a belt running tester 330 .

This belt running test machine 330 has a driving pulley 331 , a driven pulley 332 , and a guide pulley 333 . The driving pulley 331 is provided with 21 teeth engagement grooves on the periphery of the pulley. The driven pulley 332 is provided with 42 teeth engaging grooves on the periphery of the pulley. The guide pulley 333 forms a flat surface around the pulley by pressing the back surface of the belt. The driving pulley 331, the driven pulley 332, and the guide pulley 333 are all made of carbon steel (S45C).

Using the belt running tester 330 for each of the toothed belts B of Examples 6-1 to 6-13 and Comparative Example 6, tooth chipping resistance and wear resistance were evaluated in the following manner.

-Tooth chipping resistance evaluation-

First, measure the mass of the toothed belt B. Then, the toothed belt B was wound on the belt running tester 330, the driven pulley 332 received a load backward, and a tension of 216N was applied to the toothed belt B. Then, the drive pulley 331 was rotated at 3000 rpm so that the tension on the toothed belt B was 550 N, the belt was run, and the operating time until the teeth were broken was defined as the tooth durability life. The belt running test of Example 6-1 to Example 6-13 and Comparative Example 6 was carried out at room temperature, and Example 6-1 to Example 6-4 and Example 6-11 were carried out at 80°C. , Embodiment 6-12 and the belt running test of comparative example 6.

-Evaluation of abrasion resistance-

The toothed belt B was subjected to belt running for 300 hours under the same conditions as in the above wear resistance measurement. After the belt runs, measure the quality of the toothed belt B again, and calculate the quality difference before and after running as the wear quality.

<Oil resistance test>

After measuring the mass of each toothed belt of Example 6-1 to Example 6-13 and Comparative Example 6, it was immersed in new engine oil at 140° C. for 168 hours. Then, the adhering oil was sufficiently removed with an air gun, and the mass was measured again. Calculate the mass change rate (expressed in %) before and after immersion.

(test evaluation results)

Table 9 and Table 10 show the experimental results. In addition, unless otherwise specified below, the content of cellulose ultrafine fibers means parts by mass relative to 100 parts by mass of the rubber component.

[Table 9]

[Table 10]

<Average fiber diameter and fiber diameter distribution of cellulose microfibers>

As can be seen from Table 10, the distribution of the fiber diameters of the cellulose microfibers contained in the rubber compositions of the crosslinked rubbers 1 to 6 and rubbers 9 to 14 is wide.

<with running test>

-Tooth chipping resistance (room temperature)-

In Comparative Example 6 in which neither the toothed belt main body nor the rubber paste adhesive layer contained cellulose microfibers, the durability life of the teeth at room temperature was 384 hours.

In contrast, only the toothed belt main body contains cellulose microfibers, and the contents are 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. In Example 6-1 to Example 6-4 and Example 6-11 to Example 6-12, the tooth durability life at room temperature was 528 hours, 696 hours, 792 hours, 864 hours, 936 hours, and 1056 hours. That is, it can be seen from this that within the scope of the present example, as the content of cellulose microfibers increases, the durability life of the teeth becomes longer.

In addition, it can be seen that in Examples 6-4 to 6-10 in which the content of cellulose ultrafine fibers in the main body of the toothed belt is the same as 10 parts by mass, as the content of cellulose ultrafine fibers in the rubber paste adhesive layer The increase in the fiber content basically increases the durability of the teeth. Specifically, the contents of cellulose ultrafine fibers in the rubber paste adhesive layers of Examples 6-4 to 6-10 are 0 parts by mass, 1 part by mass, 3 parts by mass, 5 parts by mass, and 10 parts by mass. parts, 15 parts by mass, and 25 parts by mass. Correspondingly, the tooth durability at room temperature is 864 hours, 912 hours, 960 hours, 1032 hours, 1080 hours, 1128 hours, and 1128 hours. In addition, in Examples 6-9 and Examples 6-10, the durability life of the teeth is the same, therefore, it can be considered that when the content of cellulose ultrafine fibers is 15 parts by mass or more, the effect of improving the durability of the teeth may reach saturation.

In addition, only in Examples 6-13 in which 10 parts by mass of cellulose microfibers were contained in the rubber paste adhesive layer, the durability life of the teeth was 456 hours, which was slightly longer than that of Comparative Example 6, which was 384 hours. However, in the case of Example 6-8 in which the content of cellulose microfibers in the toothed belt main body was 10 parts by mass, although the content of cellulose microfibers in the rubber paste adhesive layer was the same as that of Examples 6-13, , but the durability life of the teeth is 1080 hours, which is significantly better than that of Examples 6-13.

From this, it can be seen that when any one of the toothed belt main body and the rubber paste adhesive layer contains cellulose microfibers, the durable life of the teeth can be improved, but the effect is greater when the toothed belt main body is contained. significantly.

-Tooth chipping resistance (80°C)-

In Comparative Example 6 in which neither the toothed belt main body nor the rubber paste adhesive layer contained cellulose microfibers, the durability life of the teeth at 80° C. was 240 hours.

In this regard, only cellulose ultrafine fibers are contained in the toothed belt main body, and the content thereof is respectively 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. In Example 6-1 to Example 6-4 and Example 6-11 to Example 6-12, the durability life of the teeth at 80°C was 432 hours, 624 hours, 744 hours, 792 hours, 888 hours and 9126 hours. Hour. That is, it can be seen from this that within the scope of the present example, as the content of cellulose microfibers increases, the durability life of the teeth at high temperatures becomes longer.

In addition, the durability life of the tooth portion at high temperature (80° C.) was shorter than that of the tooth portion at room temperature. However, the degree of deterioration can be reduced by containing cellulose microfibers. That is, in Comparative Example 6, the durability life of the teeth at room temperature was 384 hours, and correspondingly, the durability life of the teeth at 80° C. was 240 hours, and the deterioration was about 38%. In contrast, in Example 6-1 in which 1 part by mass of cellulose microfibers were contained in the toothed belt main body, the durability life of the teeth at room temperature was 528 hours, and correspondingly, the durability life of the teeth at 80°C was 432 hours, about 18% deterioration. In embodiment 6-2, embodiment 6-3, embodiment 6-4, embodiment 6-11 and embodiment 6-12, its deterioration degree is successively 10%, 6%, 8%, 5% and 14% %, it can be seen that compared with the case of not containing cellulose microfibers, the degree of deterioration is greatly reduced.

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

-Abrasion resistance-

In Comparative Example 6 in which neither the toothed belt main body nor the rubber paste adhesive layer contained cellulose microfibers, the abrasion mass was 4.1 g. In addition, only in Examples 6-1 to 6-4 and Examples 6-11 to 6-12 in which cellulose ultrafine fibers were contained in the toothed belt main body, the abrasion mass was 3.9 g to 4.3 g. From this, it can be seen that only the inclusion of cellulose microfibers in the toothed belt main body does not significantly improve the wear resistance.

On the other hand, in Examples 6-4 to 6-10 in which the content of the cellulose microfibers in the toothed belt main body was the same as 10 parts by mass, the contents of the cellulose microfibers in the rubber paste adhesive layer were respectively 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. g, 1.4g and 1.3g. That is, as the content of cellulose microfibers of the rubber paste adhesive layer increases, the wear quality decreases. Among them, if the wear mass is 3.5 g or less, it is considered to be excellently improved from the conventional situation.

In addition, in Examples 6-13 in which the main body of the toothed belt does not contain cellulose microfibers, the rubber paste adhesive layer contains 10 parts by mass of cellulose microfibers, and the wear mass is 2.0 g, which shows that the wear quality has been significantly improved. abrasion resistance.

From this, it can be seen that the effect of improving the wear resistance can be achieved by including cellulose microfibers in the rubber paste adhesive layer of the tooth portion side reinforcement cloth.

<Oil resistance test>

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

In this regard, only cellulose microfibers are contained in the toothed belt main body, and the content thereof is 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. In Example 6-1 to Example 6-4 and Example 6-11 to Example 6-12, the amount of mass change was 3.9%, 3.7%, 3.1%, 2.8%, 1.9%, and 1.5%. That is, it can be seen from this that within the scope of this example, as the content of cellulose ultrafine fibers increases, the amount of mass change becomes smaller and the oil resistance improves.

In addition, in Examples 6-4 to 6-10 in which the content of cellulose microfibers in the toothed belt body is the same as 10 parts by mass, the content of cellulose microfibers in the rubber paste adhesive layer is 0, respectively. 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, corresponding to them, the mass changes are 2.8%, 2.8%, 2.7%, 2.6%, 2.3% , 2.2% and 2.1%. That is, it can be seen from this that as the content of cellulose microfibers in the rubber paste adhesive layer increases, the rate of mass change becomes smaller and the oil resistance improves.

In addition, only in Examples 6-13 in which 10 parts by mass of cellulose microfibers were contained in the rubber paste adhesive layer, the rate of mass change was 4.3%, which was slightly suppressed from 4.4% in Comparative Example 6. In the case of Example 6-8 in which the content of the cellulose microfiber in the toothed belt main body was 10 parts by mass, the content of the cellulose microfiber in the rubber paste adhesive layer was the same as in Example 6-13, however, The mass change rate was 2.3%.

From this, it can be seen that the oil resistance can be improved by including cellulose microfibers in the main body of the toothed belt. However, only the cellulose microfibers in the rubber paste adhesive layer of the tooth side reinforcement cloth have no effect. Smaller, but also improves oil resistance. In addition, it can be seen that when both the toothed belt main body and the rubber paste adhesive layer contain cellulose microfibers, the oil resistance can be significantly improved.

Industrial Applicability

The invention is useful for belts used in transmissions.

Claims (13)

1. A transmission belt that is wound on pulleys to transmit power, characterized in that, The transmission belt has a layer made of a rubber composition containing cellulose-based ultrafine fibers and short fibers having an average diameter of 1 μm or more. 2. The transmission belt according to claim 1, characterized in that, The distribution range of the fiber diameter of the cellulose ultrafine fiber includes 20-500 nm. 3. Drive belt according to claim 1 or 2, characterized in that, Carbon black was not blended in the rubber composition. 4. A drive belt according to any one of claims 1 to 3, characterized in that The cellulose-based microfibers are produced by a mechanical defibration method. 5. A drive belt according to any one of claims 1 to 3, characterized in that The cellulose-based microfibers are produced by a chemical defibrating method. 6. A drive belt according to any one of claims 1 to 5, characterized in that The distribution range of the fiber diameter of the cellulose ultrafine fiber includes 50-500 nm. 7. A drive belt according to any one of claims 1 to 6, characterized in that The content of the cellulose-based ultrafine fibers is 1 to 25 parts by mass relative to 100 parts by mass of the rubber component of the rubber composition. 8. A drive belt according to any one of claims 1 to 7, characterized in that The rubber composition contains short fibers having a fiber diameter of 10 μm or more. 9. The power transmission belt of claim 8, wherein: The content of the short fibers relative to 100 parts by mass of the rubber component of the rubber composition is greater than the content of the cellulose-based ultrafine fibers relative to 100 parts by mass of the rubber component of the rubber composition. 10. The power transmission belt according to any one of claims 1 to 9, characterized in that, The transmission belt is a toothed belt, and includes a toothed belt main body and a tooth side reinforcement cloth, The toothed belt main body has a flat belt-shaped base and a plurality of teeth integrally arranged at intervals along the belt length direction on one side of the base, The tooth side reinforcement cloth is attached to the toothed belt main body so as to cover the tooth side surface through an adhesive layer containing a rubber component, At least one of the base portion, the tooth portion, and the adhesive layer is formed of the rubber composition containing cellulose-based ultrafine fibers and short fibers having an average diameter of 1 μm or more. 11. The power transmission belt of claim 10, wherein: The content of the cellulose-based ultrafine fibers in the rubber composition is 1 to 30 parts by mass relative to 100 parts by mass of the rubber component. 12. A drive belt according to claim 10 or 11, characterized in that, The rubber component of the rubber composition forming the main body of the toothed belt contains hydrogenated acrylonitrile rubber. 13. A drive belt as claimed in any one of claims 10 to 12, characterized in that The rubber component included in the adhesive layer includes hydrogenated acrylonitrile rubber and hydrogenated acrylonitrile rubber reinforced with a metal salt of an unsaturated carboxylic acid.