JP6680464B2 - Rubber composition - Google Patents

Description

  The present invention relates to a rubber composition.

  Rubber compositions containing so-called cellulose nanofibers are known. For example, Patent Document 1 discloses a vulcanized rubber composition containing a rubber component such as natural rubber and chemically modified microfibril cellulose.

Japanese Patent No. 4581116

  An object of the present invention is to provide a rubber composition that can improve the friction and wear characteristics of rubber parts.

  The rubber composition of the present invention contains a cellulose-based fine fiber and a rubber component, and the distribution range of the fiber diameter of the cellulose-based fine fiber is 50 to 500 nm.

  Since the rubber composition of the present invention contains the cellulosic fine fibers having a fiber diameter distribution range of 50 to 500 nm, it is excellent in behavior stability under wet conditions.

FIG. 1 is a perspective view schematically showing the wrapped V-belt of the embodiment. 2A to 2G are explanatory views showing a method of manufacturing a wrapped V-belt.

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

(Embodiment 1)
<Rubber composition>
The rubber composition according to the first embodiment contains a rubber component and cellulosic fine fibers, and the distribution range of the fiber diameter of the cellulosic fine fibers includes 50 to 500 nm. The rubber composition may contain various rubber compounding agents in addition to the cellulosic fine fibers.

(Rubber component)
As the rubber component of the rubber composition, for example, ethylene-α-olefin elastomer (EPDM, EPR, etc.), chloroprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), hydrogenated acrylonitrile rubber (H-NBR), natural Examples thereof include rubber (NR), styrene-butadiene rubber (SBR), butadiene rubber (BR), nitrile rubber (NBR), silicone rubber (Q) and fluororubber (FKM). Further, one or more blended rubbers among them may be used.

(Cellulose type fine fiber)
Cellulosic fine fibers are fiber materials derived from cellulose fine fibers composed of skeletal components of plant cell walls obtained by finely loosening plant fibers. Examples of the raw material plant of the cellulosic fine fibers include wood, bamboo, rice (rice straw), potato, sugar cane (bagasse), aquatic plants, seaweeds, and the like. Of these, wood is preferred. When the porous rubber composition forming the surface rubber layer 11a contains such cellulosic fine fibers, its high reinforcing effect is exhibited.

  The cellulosic fine fibers may be either the cellulose fine fibers themselves or the hydrophobized cellulose fine fibers that have been hydrophobized. Further, as the cellulose-based fine fiber, the cellulose fine fiber itself and the hydrophobized cellulose fine fiber may be used in combination. From the viewpoint of dispersibility, the cellulosic fine fibers preferably include hydrophobized cellulose fine fibers. Examples of the hydrophobized cellulose fine fibers include cellulose fine fibers in which some or all of the hydroxyl groups of cellulose are replaced with hydrophobic groups, and cellulose fine fibers that have been hydrophobized and surface-treated with a surface treatment agent.

  Examples of the hydrophobization for obtaining a cellulose fine fiber in which a part or all of the hydroxyl groups of cellulose are replaced with hydrophobic groups include, for example, esterification (acylation) (alkyl esterification, complex esterification, β-ketoesterification, etc. ), Alkylation, tosylation, epoxidation, arylation and the like. Of these, esterification is preferred. Specifically, in the esterified hydrophobic cellulose fine fiber, some or all of the hydroxyl groups of cellulose are carboxylic acids such as acetic acid, acetic anhydride, propionic acid and butyric acid, or their halides (especially chloride). Is a cellulose fine fiber acylated by. Examples of the surface treatment agent for obtaining the cellulose fine fibers that have been subjected to the hydrophobic surface treatment with the surface treatment agent include a silane coupling agent and the like.

  The cellulosic fine fibers preferably have a wide distribution of fiber diameters from the viewpoint of improving the stability of behavior under the condition of being exposed to water, and the distribution range of fiber diameters includes 50 to 500 nm. From that viewpoint, the lower limit of the distribution of the fiber diameter is preferably 50 nm or less, more preferably 20 nm or less, still more preferably 10 nm or less. From the same viewpoint, the upper limit is preferably 500 nm or more, more preferably 700 nm or more, still more preferably 1 μn or more. From the viewpoint of enhancing the reinforcing effect of the surface rubber layer 11a, the distribution range of the fiber diameter of the cellulosic fine fibers preferably includes 50 to 500 nm, more preferably 20 nm to 700 mm, and further preferably 10 nm to 1 μm. More preferable.

  The average fiber diameter of the cellulosic fine fibers is preferably 10 nm or more, more preferably 30 nm or more, and preferably 1400 nm or less, more preferably from the viewpoint of improving the stability of the behavior under wet conditions. It is 1000 nm or less, more preferably 800 nm or less.

  The fiber diameter distribution of the cellulosic fine fibers was obtained by freeze-grinding a rubber composition sample, observing the cross section with a transmission electron microscope (TEM), and optionally selecting 50 cellulosic fine fibers. The fiber diameter is measured, and it is determined based on the measurement result. The average fiber diameter of the cellulosic fine fibers is determined as the number average of the fiber diameters of the 50 cellulosic fine fibers selected arbitrarily.

  The cellulose-based fine fiber may be either a high aspect ratio produced by a mechanical defibration means or a needle-shaped crystal produced by a chemical defibration means. Further, as the cellulose-based fine fibers, those produced by mechanical defibration means and those produced by chemical defibration means may be used in combination. Examples of the defibrating device used for the mechanical defibrating means include a kneader such as a twin-screw kneader, a high-pressure homogenizer, a grinder, and a bead mill. Examples of the treatment used for the chemical defibration means include acid hydrolysis treatment and the like.

  The content of the cellulosic fine fibers in the rubber composition is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, still more preferably 5 parts by mass or more, based on 100 parts by mass of the rubber component. , Preferably 30 parts by mass or less, more preferably 20 parts by mass or less, still more preferably 10 parts by mass or less.

(Rubber compounding agent other than cellulosic fine fibers)
Examples of the rubber compounding agent used in addition to the cellulosic fine fibers include a reinforcing material, oil, and a crosslinking agent.

  As the reinforcing material, in the case of carbon black, for example, channel black; furnace black such as SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, N-234; FT, MT, etc. Thermal black; acetylene black and the like.

  The blending amount of carbon black is preferably 15 parts by mass or more, more preferably 30 parts by mass or more, and preferably 100 parts by mass or less, more preferably 80 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition. It is below the mass part.

  The carbon black may have at least one of a hydroxyl group, a carbonyl group and a carboxyl group.

  Examples of the reinforcing agent also include silica. As the silica, those obtained by various manufacturing methods such as a sol-gel method, a wet method and a dry method may be used. In particular, wet silica is preferable from the viewpoint of reinforcing property and low heat buildup.

  The compounding amount of silica 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 30 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition. Below the section.

  When silica is used, a silane coupling agent may be added. Examples of the silane coupling agent include sulfide-based compounds such as bis- (3- (triethoxysilyl) propyl) polysulfide (S number of polysulfide moiety: 2 to 8), mercapto-based compounds such as 3-mercaptopropyltrimethoxysilane, 3- Examples thereof include silane coupling agents which are usually used for rubber such as amino type such as aminopropyltrimethoxysilane and vinyl type such as vinyltriethoxysilane. The silane coupling agent may be used alone or in combination of two or more. The addition amount of the silane coupling agent is preferably 0.5 parts by mass to 15 parts by mass with respect to 100 parts by mass of the rubber component. When kneading using a supercritical fluid, which will be described later, by adding a silane coupling agent, the effect of further enhancing the interaction between the polymer and the filler can be obtained.

  Examples of the oil include petroleum softeners, mineral oil oils such as paraffin wax, castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, falling raw oil, wood wax, rosin, pine. Examples include vegetable oils such as oil. The oil is preferably one or more of these. The content of oil is, for example, 5 to 15 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.

  Crosslinking agents include organic peroxides and sulfur. As the cross-linking agent, an organic peroxide may be blended, sulfur may be blended, and both of them may be used in combination. The compounding amount of the crosslinking agent is, 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 organic peroxide, and is 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. For example, 1 to 5 parts by mass.

(Production of rubber composition)
In producing the rubber composition, first, cellulose-based fine fibers are added to the masticated rubber component and kneaded to be dispersed.

  Here, as a method for dispersing the cellulose-based fine fibers in the rubber component, for example, a dispersion (gel) in which the cellulose-based fine fibers are dispersed in water, is added to the rubber component masticated by an open roll, A method of evaporating water while kneading them, a cellulose-based fine fiber / rubber master obtained by evaporating water by mixing a dispersion (gel) in which cellulosic fine fibers are dispersed in water and rubber latex A method of adding the batch to the rubber component being masticated, obtained by mixing a dispersion of cellulose-based fine fibers dispersed in a solvent and a solution of the rubber component dissolved in the solvent to vaporize the solvent. A method in which a masterbatch of cellulosic fine fibers / rubber is added to the masticated rubber component, and a dispersion (gel) in which cellulosic fine fibers are dispersed in water is freeze-dried and crushed. Things and how to put into a rubber component is masticated, methods and the like to introduce cellulosic microfibers made hydrophobic in rubber component is masticated.

  Next, while kneading the rubber component and the cellulosic fine fibers, the above-mentioned various rubber compounding agents are added and the kneading is continued. For this purpose, a kneader such as a kneader or a Banbury mixer can be used.

  The uncrosslinked rubber composition obtained in the kneading step is molded and crosslinked in the usual molding / crosslinking step to obtain a crosslinked rubber composition.

  In the molding / crosslinking step, for example, a press, a vulcanizer, a continuous vulcanizer or the like may be used, or a special crosslinking group that is crosslinked by high frequency crosslinking, radiation crosslinking or electron beam crosslinking may be used.

  Molding / crosslinking conditions such as temperature, pressure, and time are appropriately set based on the composition of the filler-containing uncrosslinked rubber, the required quality of the rubber molded product, and the like. By the molding and crosslinking step, the molecules of the polymer contained in the uncrosslinked rubber composition are crosslinked by the crosslinking agent to form a network structure. Thereby, a crosslinked rubber composition is obtained.

  The specific steps may be performed according to the type of rubber molded product to be manufactured, but for example, in the case of manufacturing a wrapped V belt as shown in FIG. 1, the following steps may be performed.

  The wrapped V-belt B illustrated in FIG. 1 is used, for example, in an agricultural machine or an industrial machine, and its dimensions are, for example, a belt peripheral length of 700 to 5000 mm, a belt width of 16 to 17 mm, and a belt thickness of 8. -10 mm.

  The wrapped V-belt B has a cross-sectional shape formed in a triple layer including a bottom rubber layer 11 on the belt inner peripheral side (pulley contact side), an intermediate adhesive rubber layer 12, and an expanded rubber layer 13 on the outer peripheral side of the belt. A trapezoidal belt body 10 is provided. A core wire 14 is embedded in the adhesive rubber layer 12 so as to form a spiral having a pitch in the belt width direction. The belt body 10 is entirely covered with the reinforcing cloth 15.

  The compression rubber layer 11, the adhesive rubber layer 12, and the extension rubber layer 13 are composed of a crosslinked rubber composition. Then, at least one of the compressed rubber layer 11, the adhesive rubber layer 12, and the stretched rubber layer 13 is an uncrosslinked rubber composition obtained by kneading a rubber component with cellulose-based fine fibers and various rubber compounding agents. The article is formed of a rubber composition that is heated and pressed to crosslink with a crosslinking agent.

  The core wire 14 is made of a wire material such as a twisted yarn or a braid of polyethylene terephthalate (PET) fiber, polyethylene naphthalate (PEN) fiber, para-aramid fiber, vinylon fiber or the like. In order to impart adhesiveness to the V-ribbed belt main body 10, the core wire 14 is subjected to an adhesive treatment in which it is immersed in an RFL aqueous solution before heating and / or an adhesive treatment in which it is immersed in a rubber paste and then dried. Before the treatment, if necessary, an adhesion treatment of immersing in an adhesive solution composed of a solution of an epoxy resin, a polyisocyanate resin or the like and then heating may be performed. The outer diameter of the core wire 14 is, for example, 0.1 to 2 mm.

  The reinforcing cloth 15 is made of, for example, a woven cloth, a knitted cloth, a non-woven cloth, or the like formed from threads such as cotton, polyamide fiber, polyester fiber, and aramid fiber. The reinforcing cloth 15 has an adhesive treatment in which it is immersed in an RFL aqueous solution and heated before molding in order to impart adhesiveness to the belt body 10, and / or a rubber paste is coated on the surface of the belt body 10 side. Adhesive treatment for drying is applied.

  Next, a method for manufacturing the wrapped V-belt B according to the first embodiment will be described with reference to FIGS.

  First, a rubber sheet 11 ′ for a compressed rubber layer, a rubber sheet 12 ′ for an adhesive rubber layer, a rubber sheet 13 ′ for an extended rubber layer, a twisted yarn 14 ′ for a core wire and a cloth 15 ′ for a reinforcing cloth are provided. prepare. At this time, among the rubber sheet 11 ′ for the compressed rubber layer, the rubber sheet 12 ′ for the adhesive rubber layer, and the rubber sheet 13 ′ for the expanded rubber layer, the regenerated rubber according to the first embodiment is included in the first embodiment. The uncrosslinked rubber composition obtained by kneading the recycled rubber and the rubber compounding agent according to (1) is obtained by processing it into a sheet using a calendar roll or the like. Further, the twisting yarn 14 'for the core wire and the cloth 15' for the reinforcing cloth are subjected to an adhesive treatment.

  Next, as shown in FIG. 2A, the rubber sheet 11 'for the compressed rubber layer is wound around the mantle 21 a plurality of times, and the rubber sheet 12' for the adhesive rubber layer is wound thereon. As shown in FIG. 2B, the twisted yarn 14 ′ is spirally wound around it. Further, as shown in FIG. 2 (c), a rubber sheet 12 'for the adhesive rubber layer and a rubber sheet 13' for the stretched rubber layer are wound in this order to produce a cylindrical laminated structure 10 '.

  Next, as shown in FIG. 2D, the cylindrical laminated structure 10 ′ is sliced into a predetermined width on the mantle 21, and then they are removed from the mantle 21.

  Then, the annular laminated structure 10 ′ is wound around a pair of pulleys with the rubber sheet 11 ′ side for the compressed rubber layer outside and is rotated, as shown in FIG. 2 (e). Both sides of the laminated portion of the rubber sheet 11 'for use are cut obliquely into a V shape to adjust the volume.

  Subsequently, as shown in FIG. 2F, the outer periphery of the annular laminated structure 10 'is covered with the cloth 15'.

  Then, as shown in FIG. 2 (g), the lapped annular laminated structure 10 ′ is fitted into the groove 23 of the cylindrical mold 22, which is put in a vulcanizing can and heated and pressurized. At this time, the rubber component of the annular laminated structure 10 'is cross-linked to form the belt body 10, and the twisted yarn 14' is bonded and integrated with the belt body 10 to form the core wire 14, and the cloth 15 'is formed. The laminated V belt B according to the first embodiment is manufactured by bonding and integrating with 10 to form a reinforcing cloth 15.

  The rubber composition of the present invention can be used in various parts and products such as V-ribbed belts, toothed belts, transmission belts such as flat belts, conveyor belts, tires, etc., in addition to V-belts.

  The rubber compositions of the examples will be described below. Each example is also described in Table 1.

<Example 1>
First, a dispersion liquid in which powdered cellulose (trade name: KC Flock W-GK manufactured by Nippon Paper Industries Co., Ltd.) is dispersed in toluene is prepared, and the dispersion liquids are collided with each other using a high-pressure homogenizer to form powdered cellulose into cellulose fine fibers. Disintegration was performed to obtain a dispersion liquid in which cellulose fine fibers were dispersed in toluene. Therefore, the cellulose fine fibers are produced by mechanical defibration means and are not subjected to a hydrophobizing treatment.

  Then, a dispersion in which cellulose fine fibers are dispersed in the toluene and H-NBR (product name: Zetpol 2020 manufactured by Nippon Zeon Co., Ltd.) are dissolved in toluene, and a plasticizer (product name: W-260 manufactured by DIC) is added. The resulting solution was mixed and the toluene and the plasticizer were vaporized to prepare a masterbatch of cellulose fine fibers / H-NBR. The content of each component in the masterbatch was 25% by mass of cellulosic fine fibers, 25% by mass of plasticizer, and 50% by mass of H-NBR.

  Subsequently, EPDM was masticated, and a masterbatch was added thereto and kneaded. The amount of the masterbatch added was such that the content of the cellulosic fine fibers was 5 parts by mass with respect to 100 parts by mass of the total EPDM.

  Then, while kneading the EPDM and the cellulosic fine fiber, 30 parts by mass of carbon black FEF (manufactured by Tokai Carbon Co., Ltd., trade name: Seast SO) as a reinforcing material was added to 100 parts by mass of EPDM. 8 parts by mass of Petroleum Co., Ltd., trade name: Sunper 2280, 5 parts by mass of a cross-linking agent (manufactured by NOF CORPORATION, trade name: Peroximon F-40), and kneading continue to produce an uncrosslinked rubber composition. The thing was made.

<Example 2>
A cellulosic fine fiber / EPDM masterbatch was prepared in the same manner as in Example 1. Subsequently, EPDM was masticated, and a masterbatch was added thereto and kneaded. The amount of the masterbatch added was such that the content of the cellulosic fine fibers was 5 parts by mass with respect to 100 parts by mass of the total EPDM.

  Then, while kneading the EPDM and the cellulosic fine fibers, 30 parts by mass of carbon black FEF as a reinforcing material and 10 parts by mass of silica (manufactured by Degussa, trade name: Ultrasil VN3) per 100 parts by mass of EPDM are kneaded. Parts, 8 parts by mass of oil, and 5 parts by mass of a cross-linking agent were added, and kneading was continued to prepare an uncross-linked rubber composition. That is, 10 parts by mass of silica was further added to the composition of Example 1.

<Example 3>
A cellulosic fine fiber / EPDM masterbatch was prepared in the same manner as in Example 1. Subsequently, EPDM was masticated, and a masterbatch was added thereto and kneaded. The amount of the masterbatch added was such that the content of the cellulosic fine fibers was 5 parts by mass with respect to 100 parts by mass of the total EPDM.

  Then, while kneading EPDM and cellulosic fine fibers, 8 parts by mass of oil and 5 parts by mass of a cross-linking agent are added to 100 parts by mass of EPDM, respectively, and kneading is continued to give an uncrosslinked rubber composition. It was made. Compared with Example 1, the composition does not contain carbon black.

<Example 4>
A cellulosic fine fiber / EPDM masterbatch was prepared in the same manner as in Example 1. Subsequently, EPDM was masticated, and a masterbatch was added thereto and kneaded. The amount of the masterbatch added was such that the content of the cellulosic fine fibers was 10 parts by mass with respect to 100 parts by mass of the total EPDM.

  Then, while kneading EPDM and cellulosic fine fibers, 8 parts by mass of oil and 5 parts by mass of a cross-linking agent are added to 100 parts by mass of EPDM, respectively, and kneading is continued to give an uncrosslinked rubber composition. It was made. Compared with Example 1, the compounding amount of the cellulosic fine fibers was 5 parts by mass and the carbon black was not contained.

<Comparative Example 1>
An uncrosslinked rubber composition was prepared by masticating EPDM, adding 8 parts by mass of oil and 5 parts by mass of a crosslinking agent to 100 parts by mass of EPDM, and continuing kneading. Compared with Example 1, the composition does not contain cellulosic fine fibers and carbon black.

<Comparative example 2>
When the EPDM is masticated, 30 parts by mass of carbon black FEF as a reinforcing material, 8 parts by mass of oil, and 5 parts by mass of a crosslinking agent are added to 100 parts by mass of EPDM, and kneading is continued to continue uncrosslinking. A rubber composition was prepared. Compared with Example 1, the composition does not contain cellulosic fine fibers.

(Test evaluation method)
<Average fiber diameter / fiber diameter distribution>
Samples collected from the rubber compositions crosslinked by press molding of Examples 1 to 4 were freeze-pulverized, and their cross sections were observed with a scanning electron microscope (SEM), and 50 fibers were arbitrarily selected. And the fiber diameter was measured, and the number average thereof was calculated to obtain the average fiber diameter. Further, the maximum value and the minimum value of the fiber diameter of 50 cellulose fine fibers were obtained.

<Abrasion resistance / friction coefficient evaluation test>
For each of Examples 1 to 4 and Comparative Examples 1 and 2, test pieces of a rubber composition crosslinked by press molding were produced. The dimensions of the test piece are 5 mm square and 10 mm long.

  First, the initial mass of the test piece was measured. Then, using a pin-on-disc type friction and wear tester, the 5 mm square surface of the test piece was used as a sliding surface and brought into contact with the surface of a disc-shaped mating member made of gray cast iron (FC200). A pressure of 0.8 MPa was applied to the test piece from above, the mating material was rotated so that the sliding speed was 0.25 m / sec, and the mass of the test piece after 4 hours was measured. The change from the initial mass was defined as the wear mass. Table 1 shows ten times the wear mass in mg as an index of the wear property.

  In addition, this measurement was performed in a dry state. The temperature of the mating material was set to 60 ° C.

  Further, similarly to the above, the 5 mm square surface of the test piece was used as a sliding surface and brought into contact with the surface of the mating material made of gray cast iron, and a pressure of 0.8 MPa was applied to the test piece from above to measure the sliding speed. The friction coefficient was measured by rotating the mating member at a rate of 0.25 m / sec and measuring the force.

  Such a coefficient of friction was measured when dry, wet and dry. The dry state is a state in which the test piece and the mating material are sufficiently dried. The wet state is a state in which water is dropped on the surface of the disk-shaped mating material and water is present between the test piece and the mating material. Further, after stopping the dropping of water from the wet state, a peak is generated in the friction coefficient during the drying process. Drying means the time when such a peak occurs.

(Test evaluation result)
Table 1 shows the test results.

  Table 1 shows that the cellulose fine fibers of Examples 1 to 4 have a wide distribution of fiber diameters. Further, Examples 1 and 2 in which the cellulose-based fine fibers and carbon black are used in combination have a smaller average fiber diameter than Examples 3 and 4 in which the cellulose-based fine fibers are used but the carbon black is not used. Example 2 using silica has smaller average, maximum, and minimum fiber diameters than Example 1 using no silica.

  Further, in Examples 1 and 2, aggregates having a diameter of 5 μm or more of cellulosic fine fibers are not seen, whereas in Examples 3 and 4, the presence thereof is confirmed. That is, in Examples 1 and 2, the dispersibility of the cellulosic fine fibers is superior to that in Examples 3 and 4.

  As for the amount of wear, it is 798 in Comparative Example 1 which does not contain the cellulose-based fine fibers and carbon black. On the other hand, it is 174 in Comparative Example 2 containing only carbon black, and 198 and 163 in Examples 3 and 4 using only cellulosic fine fibers. Therefore, the cellulose-based fine fibers can realize the same abrasion resistance as that of carbon black. The abrasion resistance of the rubber composition is further improved in Example 1 in which cellulosic fine fibers and carbon black are used together as a reinforcing material, and in Example 2 in which silica is used, it is 94.

  Regarding the coefficient of friction, in the case of Examples 1 and 2, the variation of the values during drying, wet and dry is 0.1. On the other hand, in the case of Comparative Examples 1 and 2 in which the cellulosic fine fibers are not used, the coefficient of friction is greatly decreased when wet and the coefficient is greatly increased when dry, and the fluctuations are large (in order of 1.2 and 1). . 1). In Examples 3 and 4 in which the cellulosic fine fibers are used, the width of fluctuation is 0.2, and although it is large as compared with Examples 1 and 2, it is significantly improved as compared with Comparative Examples 1 and 2. ing.

  As described above, by blending the cellulose-based fine fiber and carbon black together, a rubber composition having a small variation in the friction coefficient can be obtained under the condition of being wet and dried. Therefore, the rubber component made of such a rubber composition has stable behavior under the condition of being exposed to water.

  As described above, the use of cellulosic fine fibers as the reinforcing material of the rubber composition and the combined use of carbon black make it possible to obtain a rubber component having high abrasion resistance and stable behavior under wet conditions.

  The present invention is useful in the field of rubber compositions.

10 Belt Main Body 11 Bottom Rubber Layer 12 Adhesive Rubber Layer 13 Stretching Rubber Layer 14 Core Wire 15 Reinforcement Cloth 10 'Laminated Structure 11' Rubber Sheet 12 'Rubber Sheet 13' Rubber Sheet 14 'Thread 15' Cloth 21 Mantle 22 Cylindrical Mold 23 groove

Claims (6)

In a rubber composition containing a rubber component and a cellulosic fine fiber,
Distribution range of the fiber diameter of the cellulose fine fibers, a rubber composition which comprises a range of 50 to 500 nm. The rubber composition according to claim 1,
A rubber composition comprising carbon black as a filler. The rubber composition according to claim 2,
The rubber composition, wherein the carbon black has at least one of a hydroxyl group, a carbonyl group and a carboxyl group. The rubber composition according to any one of claims 1 to 3,
A rubber composition comprising silica as a filler. The rubber composition according to any one of claims 1 to 4,
The rubber composition, wherein the rubber component is an ethylene-α-olefin-based elastomer.   The rubber composition according to any one of claims 1 to 5,
  The rubber composition, wherein the distribution range of the fiber diameter of the cellulosic fine fibers includes a range of 50 to 1000 nm.

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