Metal cord-rubber composite

Abstract

To provide a metal cord-rubber composite using a rubber composition that is excellent in workability including rubber scorching and moldability and can contribute to improvement of sustainability.SOLUTION: A metal cord-rubber composite is formed by coating a metal cord with a rubber composition. The rubber composition contains a rubber component (A) including isoprene rubber and at least one resin component (B) selected from terpene resin and rosin resin.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a metal cord-rubber composite. [Background technology]

[0002] Generally, a tire that requires strength may have a carcass layer formed of cords embedded in the ring-shaped tire body along the meridian direction inside the tire, and a belt disposed on the tire radially outside of the carcass layer. This belt is usually formed of multiple belt layers in which steel cords are covered with coating rubber (hereinafter referred to as "belt coating rubber" or "coating rubber"), and provides the tire with load-bearing properties, traction resistance, etc. The belt coating rubber is required to have high durability, especially high crack growth resistance.

[0003] On the other hand, in recent years, from the viewpoint of improving fuel efficiency of automobiles, there has been an increasing demand for belt coating rubber to have low loss properties in order to reduce the rolling resistance of tires.

[0004] In this regard, for example, when the amount of carbon black mixed in the belt coating rubber is reduced in order to improve the low loss property, the crack resistance tends to deteriorate. Therefore, there has been a demand for the development of a technology that can achieve both low loss property and crack resistance.

[0005] As an example of such a technique, Patent Document 1 discloses a rubber composition for belt coating rubber, which contains carbon black with low polarity and a solubility parameter value (SP value) of 10 (cal / cm 3 ) 1 / 2 It is disclosed that by using the above-mentioned resin, particularly a phenolic resin, network formation between carbon blacks via the resin is promoted, making it possible to exhibit high crack propagation resistance while maintaining excellent low heat buildup properties. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2022-132289 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the above-mentioned conventional rubber compositions have problems such as rubber scorching and air getting between the rubber members after molding, and there is room for improvement in terms of workability.

[0008] Meanwhile, in recent years, from the perspective of social sustainability, there has been a demand to use so-called sustainable materials, such as materials derived from biological resources (biomass resources) and materials derived from renewable resources (recycled resources), for various components used in rubber products such as tires, and there has also been a demand to improve the usage rate of sustainable materials (hereinafter sometimes referred to as the "sustainability rate") in rubber compositions for tire components.

[0009] Therefore, an object of the present invention is to provide a metal cord-rubber composite that uses a rubber composition that is excellent in workability, including rubber fading and moldability, and that can contribute to improving sustainability. [Means for solving the problem]

[0010] That is, the essential configuration of the metal cord-rubber composite of the present invention that solves the above problems is as follows.

[0011] [1] A metal cord-rubber composite comprising a metal cord coated with a rubber composition, The metal cord-rubber composite, characterized in that the rubber composition contains a rubber component (A) containing an isoprene-based rubber, and at least one resin component (B) selected from a terpene-based resin and a rosin-based resin. In such a metal cord-rubber composite of the present invention, the rubber composition used has excellent workability, including rubber fading and moldability, and can also contribute to improving sustainability.

[0012] [2] The metal cord-rubber composite according to [1], wherein the content of the resin component (B) in the rubber composition is 10 parts by mass or less per 100 parts by mass of the rubber component (A). In this case, the durability of the metal cord-rubber composite body to which the rubber composition is applied can be well maintained.

[0013] [3] The metal cord-rubber composite according to [1] or [2], wherein the surface of the metal cord has an N atom content of 2 atomic % or more and 60 atomic % or less and a Cu / Zn ratio of 1 or more and 4 or less. In this case, the adhesion between the rubber composition and the metal cord can be improved, and deterioration of the initial adhesion between the rubber composition and the metal cord can be suppressed.

[0014] [4] The metal cord-rubber composite according to any one of [1] to [3], wherein the metal cord is a metal cord made of a single metal wire having a brass plating applied to its circumferential surface, or a metal cord made of a plurality of twisted metal wires, and the composition of the brass plating is Cu: 40 to 80 mass % and Zn: 20 to 60 mass %. In this case, the cord processability and adhesion to the rubber composition can be improved.

[0015] [5] The metal cord-rubber composite according to any one of [1] to [4], wherein the metal cord is a metal cord that has been surface-treated with a buffer solution having a pH of 5.0 to 7.2 and treated with at least one triazole compound selected from 1,2,4-triazole, 1,2,3-triazole, 3-amino-1,2,4-triazole, 4-amino-1,2,4-triazole, benzotriazole, tolyltriazole, and 3-mercapto-1,2,4-triazole. In this case, the adhesion between the rubber composition and the metal cord can be improved, and deterioration of the initial adhesion between the rubber composition and the metal cord can be suppressed. Effect of the Invention

[0016] According to the present invention, it is possible to provide a metal cord-rubber composite in which the rubber composition used is excellent in workability, including rubber fading and moldability, and which can contribute to improving sustainability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The metal cord-rubber composite body of the present invention will be illustrated in detail below based on embodiments thereof.

[0018] <Definition> The compounds described herein may be derived in whole or in part from fossil sources, from biological sources such as plant sources, from recycled sources such as used tires, or from a mixture of two or more of fossil sources, biological sources, and / or renewable sources.

[0019] In this specification, the "sustainability rate" refers to the total mass ratio of components derived from biological resources (biomass resources) and components derived from renewable resources (recycled resources) in a target material.

[0020] In this specification, the biological resources (biomass resources) refer to carbon-neutral organic resources derived from living organisms, and include, for example, those stored in the form of starch or cellulose, the bodies of animals that grow by eating plants, and products obtained by processing plants or animals, and are resources other than fossil resources (petroleum, coal, natural gas, etc.). The biological resources may be edible or non-edible, but are preferably non-edible from the viewpoint of not competing with food and of effective resource utilization.

[0021] Specific examples of the biological resources include cellulosic crops (pulp, kenaf, wheat straw, rice straw, waste paper, papermaking residues, etc.), wood, charcoal, compost, food waste, vegetable oil residues, fishery residues, livestock waste, food waste, wastewater sludge, natural rubber, cotton, oils and fats (palm oil, castor oil, cottonseed oil, soybean oil, linseed oil, rapeseed oil, coconut oil, peanut oil, tall oil, corn oil, rice oil, safflower oil, sesame oil, olive ... Examples of the biological resources include crops (corn, wheat, rice, rice husks, rice bran, old rice, potatoes, buckwheat, cassava, sago palm, sugarcane, etc.), bagasse (i.e., the residue after squeezing juice from sugarcane), soybeans, soybean pulp, essential oils (pine oil, orange oil, eucalyptus oil, etc.), pulp black liquor, algae, etc. The biological resources may be processed (i.e., biological resource-derived substances). Examples of the processing methods include biological processing methods that utilize the functions of microorganisms, plants, animals, and tissue cultures thereof; chemical processing methods that utilize acids, alkalis, catalysts, thermal energy, light energy, etc.; physical processing methods such as micronization, compression, microwave processing, and electromagnetic wave processing; and the like. The biological resources may also be extracted and refined from the biological resources or biological resources that have been processed (i.e., biological resource-derived substances). For example, sugars, proteins, amino acids, fatty acids, fatty acid esters, etc., purified from the biological resources can be used. Examples of the sugars include sucrose, glucose, trehalose, fructose, lactose, galactose, xylose, allose, talose, gulose, altrose, mannose, idose, arabinose, apiose, maltose, cellulose, starch, chitin, etc., derived from biological resources. Examples of the proteins include compounds derived from biological resources and formed by linking amino acids (preferably L-amino acids), including oligopeptides such as dipeptides. Examples of the amino acids include valine, leucine, isoleucine, arginine, lysine, asparagine, glutamine, phenylalanine, etc., derived from biological resources, and among these, valine, leucine, isoleucine, arginine, and phenylalanine are preferred.The amino acid may be either an L-amino acid or a D-amino acid, but L-amino acids are preferred from the viewpoints of abundance in nature and ease of availability. The fatty acids include butyric acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, etc., which are derived from biological resources. The fatty acid esters include modified products of vegetable oils, animal oils, and fats and oils derived from biological resources. These biological resources may be contaminated with various materials and impurities.

[0022] In this specification, the term "recycled resources" refers to resources obtained by regenerating (recycling) products that have been used once, or that have been collected without being used, or that have been discarded. For example, recycled resources include resources obtained by regenerating (recycling) used rubber products such as used tires.

[0023] <Metal cord-rubber composite> A metal cord-rubber composite according to one embodiment of the present invention (hereinafter sometimes referred to as the "metal cord-rubber composite of this embodiment") is a metal cord-rubber composite formed by coating a metal cord with a rubber composition, and is characterized in that the rubber composition (hereinafter sometimes referred to as the "rubber composition of this embodiment") contains a rubber component (A) including an isoprene-based rubber, and at least one resin component (B) selected from a terpene-based resin and a rosin-based resin.

[0024] In general, conventional rubber compositions used in metal cord-rubber composites contain resin components such as petroleum resins to improve tack (adhesiveness). In contrast, the rubber composition used in the metal cord-rubber composite of the present embodiment contains at least one resin component (B) selected from terpene resins and rosin resins. These terpene resins and rosin resins have high molecular weight uniformity compared to petroleum resins, which has a favorable effect on compatibility in the rubber composition, thereby improving workability, including rubber scorching and moldability, of the rubber composition.

[0025] In addition, terpene-based resins and rosin-based resins are materials derived from biological resources (biomass resources). Therefore, by blending at least one resin component (B) selected from terpene-based resins and rosin-based resins into the rubber composition used in the metal cord-rubber composite, the metal cord-rubber composite to which the rubber composition is applied can contribute to improving sustainability.

[0026] Therefore, according to the metal cord-rubber composite of this embodiment, the rubber composition used has excellent workability, including rubber fading and moldability, and can contribute to improving sustainability.

[0027] Furthermore, at least one resin component (B) selected from a terpene resin and a rosin resin contained in the rubber composition of the present embodiment has high affinity with a metal cord, so that when the rubber composition is coated on the metal cord, it can be concentrated near the metal cord. This uneven distribution induces a reaction between the isoprene rubber contained as the rubber component (A) and the metal cord, which can improve the adhesion between the rubber composition and the metal cord.

[0028] (Rubber component (A)) The rubber composition of the present embodiment contains a rubber component (A), which provides rubber elasticity to the composition. The rubber component (A) has a sustainability rate of preferably 30% by mass or more, more preferably 40% by mass or more, more preferably 50% by mass or more, more preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 100% by mass.

[0029] As the rubber component (A), the rubber derived from biological resources and the rubber derived from recycled resources are preferred. Here, the proportion of the monomer components derived from biological resources in 100 mol% of the monomer components constituting the rubber derived from biological resources is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, still more preferably 90 mol% or more, particularly preferably 95 mol% or more, and may be 100 mol%. The proportion of monomer components derived from recycled resources in 100 mol% of monomer components constituting the rubber derived from recycled resources is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, still more preferably 90 mol% or more, particularly preferably 95 mol% or more, and may be 100 mol%.

[0030] The rubber component (A) is a component that contributes to crosslinking, and usually has a weight average molecular weight (Mw) of 10,000 or more, preferably 50,000 or more, more preferably 150,000 or more, and even more preferably 200,000 or more, and preferably 5,000,000 or less, more preferably 2,000,000 or less, more preferably 1,500,000 or less, and even more preferably 1,300,000 or less. In this specification, the weight average molecular weight (Mw) of the rubber component (A) can be determined, for example, by converting the weight average molecular weight (Mw) into standard polystyrene based on a measurement value obtained by gel permeation chromatography (GPC) (GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: TSKGEL SUPERMULTIPORE HZ-M manufactured by Tosoh Corporation).

[0031] In the rubber composition of the present embodiment, the rubber component (A) contains an isoprene-based rubber. The isoprene-based rubber refers to a rubber containing a unit derived from isoprene as a monomer unit, and is one of diene-based rubbers. By containing the isoprene-based rubber in the rubber component (A), it is possible to improve low loss properties and abrasion resistance.

[0032] Examples of the isoprene-based rubber include natural rubber (NR), synthetic isoprene rubber (IR), modified natural rubber (modified NR), modified natural rubber (modified NR), and modified synthetic isoprene rubber (modified IR). Examples of the natural rubber (NR) that can be used include those commonly used in the tire industry, such as RSS#3 and TSR20 (e.g., SIR20 and STR20). The origin of the natural rubber (NR) is not particularly limited, and examples of the natural rubber include those derived from Hevea brasiliensis, guayule, and Russian dandelion. Examples of the synthetic isoprene rubber (IR) are not particularly limited, and examples of the synthetic isoprene rubber that can be used include those commonly used in the tire industry, such as IR2200. Examples of the modified NR include deproteinized natural rubber (DPNR) and highly purified natural rubber (UPNR). Examples of the modified NR include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. The modified IR includes epoxidized synthetic isoprene rubber, hydrogenated synthetic isoprene rubber, grafted synthetic isoprene rubber, etc. These isoprene-based rubbers may be used alone or in combination of two or more. Among these, NR is preferred as the isoprene-based rubber.

[0033] The isoprene-based rubber preferably has a sustainability rate of 30% by mass or more, more preferably 40% by mass or more, more preferably 50% by mass or more, still more preferably 60% by mass or more, still more preferably 70% by mass or more, even more preferably 80% by mass or more, still more preferably 90% by mass or more, and particularly preferably 100% by mass. In order to set the sustainability rate of the isoprene-based rubber within the above range, it is preferable to use natural rubber (NR) or a polymer synthesized using isoprene derived from biological resources or isoprene derived from renewable resources as a monomer component. In this case, the synthesized polymer may be a homopolymer of a monomer derived from biological resources, a homopolymer of a monomer derived from renewable resources, a copolymer of a monomer derived from biological resources and a monomer derived from renewable resources, or a copolymer of a monomer derived from biological resources and / or a monomer derived from renewable resources and a monomer derived from a fossil resource (petroleum, etc.).

[0034] The content of the isoprene-based rubber is preferably 60% by mass or more, more preferably 65% ​​by mass or more, and even more preferably 70% by mass or more, in 100 parts by mass of the rubber component (A) from the viewpoints of adhesion between the metal cord and the rubber composition and rubber durability. The rubber component (A) may be composed only of the isoprene-based rubber.

[0035] In the rubber composition of the present embodiment, the rubber component (A) may contain a butadiene-based rubber. The butadiene-based rubber refers to a rubber containing a unit derived from butadiene as a monomer unit, and is one of diene-based rubbers. Examples of the butadiene-based rubber include butadiene rubber (BR) and aromatic vinyl compound-butadiene copolymer rubber (e.g., styrene-butadiene rubber (SBR)). Here, butadiene, which is a raw material for butadiene-based rubber, is preferably derived from a biological resource or a recycled resource.

[0036] The rubber component (A) preferably contains a butadiene rubber (BR), which can improve the physical properties of the rubber composition, such as the elongation at break (EB). The rubber component (A) more preferably contains natural rubber (NR) in addition to the butadiene rubber (BR). By using a combination of natural rubber and butadiene rubber as the rubber component (A), the elongation at break (EB) after thermal aging of the rubber composition can be further improved.

[0037] In the rubber composition of the present embodiment, the total amount of styrene in the rubber component (A) is preferably 5% by mass or less, more preferably 3% by mass or less, and may be 0% by mass. If the total amount of styrene in the rubber component (A) is 5% by mass or less, the physical properties of the rubber composition are maintained, and the elongation at break (EB) after thermal aging can be sufficiently improved.

[0038] Examples of the butadiene rubber (BR) include high cis content butadiene rubber, low cis content butadiene rubber, and butadiene rubber containing syndiotactic polybutadiene crystals. Commercially available products can be used as the butadiene rubber (BR), and examples of commercially available butadiene rubbers include products from UBE Elastomers Co., Ltd., ENEOS Materials Corporation, Asahi Kasei Co., Ltd., and Zeon Corporation. These butadiene rubbers may be used alone or in combination of two or more.

[0039] Examples of the aromatic vinyl compound-butadiene copolymer rubber (e.g., SBR) include emulsion-polymerized aromatic vinyl compound-butadiene copolymer rubber (e.g., emulsion-polymerized styrene-butadiene rubber (E-SBR)), solution-polymerized aromatic vinyl compound-butadiene copolymer rubber (e.g., solution-polymerized styrene-butadiene rubber (S-SBR)), and the like. In the aromatic vinyl compound-butadiene copolymer rubber, examples of the aromatic vinyl compound (aromatic vinyl monomer) include styrene, vinylnaphthalene, divinylnaphthalene, and the like. These aromatic vinyl compounds may be used alone or in combination of two or more. Among these, styrene is preferred, and styrene derived from biological resources and styrene derived from recycled resources are particularly preferred. That is, the aromatic vinyl compound-butadiene copolymer rubber is preferably SBR. The styrene may have a substituent. As the aromatic vinyl compound-butadiene copolymer rubber, commercially available products can be used, and examples of the commercially available products include products from Asahi Kasei Corporation, ENEOS Materials Corporation, Nippon Zeon Corporation, Sumitomo Chemical Co., Ltd., and the like. These aromatic vinyl compound-butadiene copolymer rubbers may be used alone or in combination of two or more.

[0040] The butadiene-based rubber has a sustainability rate of preferably 30% by mass or more, more preferably 40% by mass or more, more preferably 50% by mass or more, still more preferably 60% by mass or more, still more preferably 70% by mass or more, even more preferably 80% by mass or more, still more preferably 90% by mass or more, and particularly preferably 100% by mass. In order to make the sustainability rate of the butadiene-based rubber fall within the above range, for example, a polymer synthesized using butadiene derived from biological resources, butadiene derived from renewable resources, aromatic vinyl compounds derived from biological resources (e.g., styrene derived from biological resources), and aromatic vinyl compounds derived from renewable resources (e.g., styrene derived from renewable resources) as monomer components may be used. In this case, the synthesized polymer may be a homopolymer of a monomer derived from biological resources, a homopolymer of a monomer derived from renewable resources, a copolymer of a monomer derived from biological resources and a monomer derived from renewable resources, or a copolymer of a monomer derived from biological resources and / or a monomer derived from renewable resources and a monomer derived from a fossil resource (petroleum, etc.). In addition, the butadiene rubber (B-BR) derived from biological resources (biomass resources) and aromatic vinyl compound-butadiene copolymer rubber derived from biological resources (e.g., styrene-butadiene rubber (B-SBR) derived from biological resources (biomass resources)) include not only rubber obtained by polymerizing butadiene, etc. according to a conventional method, but also rubber obtained by reactions or enzyme reactions caused by microorganisms, plants, animals, and tissue cultures thereof (hereinafter also referred to as "microorganisms, etc.").

[0041] In order to set the sustainability rate of the entire rubber component (A) within the above range, it is preferable to use natural rubber (NR) as the rubber component or a polymer synthesized using monomer components derived from biological resources or monomer components derived from recycled resources as monomer components.

[0042] Generally, materials for rubber compositions for tires (rubber and its monomers, fillers, resins, etc.) require large-scale manufacturing equipment for their production, and are therefore usually produced in large factories in specific regions, and a lot of energy is required for the storage and transportation of raw materials and products. In contrast, materials derived from biological resources (biomass resources) are derived from agricultural products, forests, etc. in each region, and can be produced on a small scale by fermentation of microorganisms and catalytic reactions, so by utilizing products and waste from each region, the energy required for the transportation and storage of raw materials can be reduced, and further the energy required for the transportation and storage of the produced materials to tire factories can also be reduced, which is environmentally friendly. In addition, materials derived from regenerated resources (recycled resources) can be obtained, for example, by dismantling and pyrolyzing used tires to extract materials that constitute tires, such as rubber, fillers, and steel cords. In addition, sulfur can be obtained from biological resources or processed products of biological resources by a method including a desulfurization step of desulfurizing biological resources or processed products of biological resources to remove sulfur-containing substances from the biological resources or processed products of biological resources, a recovery step of recovering sulfur from the desulfurization residue generated in the desulfurization step, and a processing step of processing the recovered sulfur into sulfur for vulcanization (for example, the method described in Japanese Patent Application No. 2022-140390), and materials for rubber compositions for tires can be obtained from various wastes and used items. In this way, by using sustainable materials (materials derived from biological resources or materials derived from recycled resources), it is possible to reduce the overall environmental load in tire manufacturing, such as reducing carbon dioxide emissions (LCCO2) over the entire life cycle, reducing energy consumption (LCE) over the entire life cycle, reducing costs (LCC) incurred over the entire life cycle, and reducing the amount of fossil resources used.

[0043] In addition, when producing the rubber composition, the ratio of the monomer components derived from biological resources, the monomer components derived from renewable resources, and the monomer components derived from fossil resources can be appropriately selected according to the supply situation of biological resources, recycled resources, and fossil resources (e.g., monomer components derived from fossil resources) and / or market demand (e.g., demand for biological resources as food), and the monomer components derived from biological resources, the monomer components derived from renewable resources, and the monomer components derived from fossil resources can be polymerized to obtain rubber derived from sustainable materials (materials derived from biological resources or materials derived from renewable resources) having performance equivalent to that of conventional synthetic rubber. When using monomer components derived from renewable resources, it may be difficult to separate them from monomer components derived from fossil resources due to the manufacturing process of the monomer. In that case, the impact on the environment can be evaluated by adopting the concept of mass balance.

[0044] The ratio of each monomer unit (e.g., unit derived from isoprene, unit derived from butadiene, unit derived from aromatic vinyl compound) in the entire rubber component (A) can be adjusted appropriately. The ratio of each monomer unit in the entire rubber component (A) can be adjusted, for example, by appropriately combining the above-mentioned isoprene-based rubber and butadiene-based rubber. In addition, the ratio of cis-bond units in the unit derived from butadiene can also be adjusted appropriately. In this specification, the term "monomer unit" refers to a structural unit of a polymer, the term "unit derived from isoprene" refers to a structural unit in a polymer constituted based on the monomer isoprene (including the isoprene unit in natural rubber), the term "unit derived from butadiene" refers to a structural unit in a polymer constituted based on the monomer butadiene, and the term "unit derived from an aromatic vinyl compound" refers to a structural unit in a polymer constituted based on the monomer aromatic vinyl compound. In this specification, the ratio of each monomer unit is measured by NMR.

[0045] The rubber component (A) may contain diene rubbers such as acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR), styrene-isoprene-butadiene copolymer rubber (SIBR), etc., in addition to the above-mentioned isoprene-based rubber, butadiene rubber (BR), and aromatic vinyl compound-butadiene copolymer rubber (e.g., SBR). These rubber components (A) may be used alone or in combination of two or more.

[0046] The rubber component (A) may be modified to introduce a functional group that interacts with a filler such as carbon black or silica. Examples of the functional group include amino, amide, isocyanate, imino, imidazole, urea, ammonium, imide, hydrazo, azo, diazo, carboxyl, nitrile, pyridyl, alkoxy, hydroxyl, oxy, epoxy, ether, carbonyl, oxycarbonyl, silyl, alkoxysilyl, mercapto, sulfide, disulfide, sulfonyl, sulfinyl, and thiocarbonyl groups, and these functional groups may have a substituent. These functional groups may be introduced into the rubber component alone or in combination of two or more. Among these, an amino group, an alkoxy group, and an alkoxysilyl group are preferred, and a substituted amino group in which a hydrogen atom of an amino group is substituted with an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and an alkoxysilyl group having 1 to 6 carbon atoms are more preferred.

[0047] The functional group can be introduced, for example, by reacting a compound (modifier) ​​having the functional group with the rubber component. The functional group is a modified functional group having an interactive property with a filler such as silica or carbon black, and examples thereof include a nitrogen-containing functional group, a silicon-containing functional group, and an oxygen-containing functional group. Examples of compounds (modifiers) having a nitrogen-containing functional group include amino group-containing compounds, and examples of compounds (modifiers) having a silicon-containing functional group include silicon halides and hydrocarbyloxysilane compounds. Examples of compounds (modifiers) having an oxygen-containing functional group include alkoxy group-containing compounds, alkylene oxide group-containing compounds, and trialkylsilyloxy group-containing compounds. More specifically, examples of the compounds include those described in International Publication No. 2016 / 194316 and International Publication No. 2019 / 117256. These modifiers may be used alone or in combination of two or more.

[0048] The rubber derived from sustainable materials (materials derived from biological resources or materials derived from renewable resources) can be produced in the same manner as conventional synthetic rubber derived from fossil resources, for example, by using monomer components derived from biological resources or monomer components derived from renewable resources, and, if necessary, monomer components derived from fossil resources. The rubber derived from sustainable materials (particularly rubber derived from biological resources) can also be obtained by reactions with microorganisms or enzyme reactions.

[0049] Regarding the method for preparing rubber derived from biological resources from the above-mentioned biological resources, for example, the method described in JP 2022-179158 A can be used. For example, by using butadiene obtained from biological resources as a monomer component, it is possible to obtain butadiene rubber (B-BR) derived from biological resources (biomass resources), and by using styrene obtained from biological resources and butadiene obtained from biological resources as monomer components, it is possible to obtain styrene-butadiene rubber (B-SBR) derived from biological resources (biomass resources). Here, methods for obtaining B-BR and B-SBR from biological resources include, in addition to artificial polymerization methods, methods of polymerization in vivo, and methods of polymerization with biological enzymes. The molecular weight, branching, microstructure, etc. of the obtained B-BR and B-SBR can be appropriately adjusted by changing the polymerization conditions according to known methods according to the target tire performance.

[0050] As the butadiene obtained from the biological resources, butadiene derived from alkyl alcohols (preferably ethanol and butanol, more preferably butanol), butadiene derived from alkenes (preferably ethylene), and butadiene derived from unsaturated carboxylic acids (preferably tiglic acid) can be suitably used. Two or more of these butadienes may be used in combination. As the styrene obtained from the biological resources, styrene obtained from a plant (preferably a plant belonging to the family Hamamelidaceae, Styraxaceae, or Apocynaceae, more preferably a plant belonging to the genera Liquidamus, Styrax, or Catharanthus, and even more preferably Sweetgum, Styrax rosa, or Catharanthus roseus) or a microorganism (preferably a microorganism belonging to the genera Penicillium or Escherichia, more preferably P. citrinum or transformed E. coli) can be suitably used. Two or more of these styrenes may be used in combination.

[0051] Recently, biomass combinat mainly using bioethanol, bioethylene, etc. are planned, but bioethanol and bioethylene are mainly produced using sugars and / or cellulose as biological resources, and other biological resources such as proteins, lipids, and amino acids cannot be effectively utilized. Furthermore, sugars compete with food, and excessive use of cellulose leads to deforestation. Therefore, it is preferable to use multiple types of monomer components derived from biological resources as the monomer components derived from the biological resources, or to use monomer components derived from biological resources, monomer components derived from renewable resources, and monomer components derived from fossil resources in combination, and further to appropriately adjust the ratio of these monomer components. This makes it possible to effectively utilize a wide range of biological resources and renewable resources such as sugars, proteins, and lipids without relying on one type of biological resource, and to stably supply rubber derived from sustainable materials, and further to consider the environment depending on the situation at the time of production. In addition, when using multiple types of monomer components derived from biological resources, it is preferable to use monomer components derived from different biological resources, i.e., monomer components obtained from different biological resources. Specifically, it is preferable to use a mixture of butadiene derived from multiple types of biological resources with different origins as the butadiene derived from biological resources, and / or to use a mixture of styrene derived from multiple types of biological resources with different origins as the styrene derived from biological resources. This allows multiple types of biological resources to be effectively utilized.

[0052] (Resin component (B)) The rubber composition of the present embodiment contains at least one resin component (B) selected from a terpene resin and a rosin resin. As described above, by blending at least one resin component (B) selected from a terpene resin and a rosin resin, the workability of the rubber composition, including rubber fading and moldability, can be improved. In addition, since the terpene resin and the rosin resin are naturally derived sustainable resins, blending the terpene resin and / or the rosin resin in the rubber composition contributes to improving sustainability and further reduces the environmental load.

[0053] The resin component (B) may be hydrogenated, i.e., may be a hydrogenated resin (hydrogenated resin). In addition, the resin may be modified to introduce a functional group that interacts with a filler such as carbon black or silica. Examples of the functional group include amino groups, amide groups, isocyanate groups, imino groups, imidazole groups, urea groups, ammonium groups, imide groups, hydrazo groups, azo groups, diazo groups, carboxyl groups, nitrile groups, pyridyl groups, alkoxy groups, hydroxyl groups, oxy groups, epoxy groups, ether groups, carbonyl groups, oxycarbonyl groups, silyl groups, alkoxysilyl groups, mercapto groups, sulfide groups, disulfide groups, sulfonyl groups, sulfinyl groups, and thiocarbonyl groups.

[0054] The terpene resin is a solid resin obtained by blending turpentine obtained at the same time when rosin is obtained from pine trees, or a polymerization component separated therefrom, and polymerizing it using a Friedel-Crafts catalyst, and examples of the terpene resin include β-pinene resin and α-pinene resin. The terpene resin also includes terpene-aromatic compound resin, and representative examples of the terpene-aromatic compound resin include terpene-phenol resin and styrene-terpene resin. The terpene-phenol resin can be obtained by reacting terpenes with various phenols using a Friedel-Crafts catalyst, or by further condensing with formalin. The styrene-terpene resin can be obtained by reacting styrene with terpenes using a Friedel-Crafts catalyst. The terpenes as the raw material are not particularly limited, and are preferably monoterpene hydrocarbons such as α-pinene and limonene, more preferably those containing α-pinene, and particularly preferably α-pinene.

[0055] The rosin-based resin includes natural resin rosin such as gum rosin, tall oil rosin, and wood rosin contained in raw pine tar and tall oil, and modified rosin, rosin derivatives, and modified rosin derivatives such as polymerized rosin, partially hydrogenated rosin, glycerin ester rosin, partially hydrogenated rosin, and fully hydrogenated rosin, pentaerythritol ester rosin, partially hydrogenated rosin, and polymerized rosin. The rosin resin may be a commercially available product, such as Neotoll 105 (manufactured by Harima Chemical Co., Ltd.), SN Tack 754 (manufactured by San Nopco Co., Ltd.), Lime Resin No. 1, Pencel A, and Pencel AD (manufactured by Arakawa Chemical Co., Ltd.), Polypale and Pentalin C (manufactured by Eastman Chemical Co., Ltd.), and High Rosin (registered trademark) S (manufactured by Taisha Matsuseiyu Co., Ltd.).

[0056] The softening point of the resin component (B) is preferably 30° C. or higher, more preferably 60° C. or higher, more preferably 80° C. or higher, more preferably higher than 110° C., more preferably 116° C. or higher, more preferably 120° C. or higher, more preferably 123° C. or higher, and even more preferably 127° C. or higher. From the viewpoint of processability, the softening point of the resin component (B) is preferably 160° C. or lower, more preferably 150° C. or lower, more preferably 145° C. or lower, more preferably 141° C. or lower, and even more preferably 136° C. or lower. In this specification, the softening point of the resin is the temperature at which the ball drops when the softening point defined in JIS K 6220-1:2015 (ISO 28641:2010) is measured using a ring and ball softening point tester.

[0057] The content of the resin component (B) is preferably 0.5 parts by mass or more relative to 100 parts by mass of the rubber component (A). In this case, the workability of the rubber composition can be sufficiently improved, and the content of the resin component (B) can further contribute to improving sustainability. In addition, the content of the resin component (B) is preferably 10 parts by mass or less relative to 100 parts by mass of the rubber component (A). In this case, the durability of the metal cord-rubber composite to which the rubber composition is applied can be well maintained. From the same viewpoint, the content of the resin component (B) relative to 100 parts by mass of the rubber component (A) is more preferably 1.5 parts by mass or more, and more preferably 7 parts by mass or less.

[0058] (Other resins) The rubber composition of the present embodiment may contain other resins other than the above-mentioned resin component (B). Examples of the other resins include C5 resins, C5-C9 resins, C9 resins, cyclopentadiene resins, aromatic resins, coumarone resins, indene resins, coumarone-indene resins, olefin resins, polyurethane resins, acrylic resins, etc. These other resins may be used alone or in combination of two or more.

[0059] The other resin may be hydrogenated, i.e., may be a hydrogenated resin (hydrogenated resin). In addition, the resin may be modified to introduce a functional group that interacts with a filler such as carbon black or silica. Examples of the functional group include an amino group, an amide group, an isocyanate group, an imino group, an imidazole group, a urea group, an ammonium group, an imide group, a hydrazo group, an azo group, a diazo group, a carboxyl group, a nitrile group, a pyridyl group, an alkoxy group, a hydroxyl group, an oxy group, an epoxy group, an ether group, a carbonyl group, an oxycarbonyl group, a silyl group, an alkoxysilyl group, a mercapto group, a sulfide group, a disulfide group, a sulfonyl group, a sulfinyl group, and a thiocarbonyl group.

[0060] The C5 resins include aliphatic petroleum resins obtained by (co)polymerizing C5 fractions obtained by thermal cracking of naphtha in the petrochemical industry. C5 fractions usually include olefinic hydrocarbons such as 1-pentene, 2-pentene, 2-methyl-1-butene, 2-methyl-2-butene, and 3-methyl-1-butene, and diolefinic hydrocarbons such as 2-methyl-1,3-butadiene, 1,2-pentadiene, 1,3-pentadiene, and 3-methyl-1,2-butadiene.

[0061] The C5-C9 resin refers to a C5-C9 synthetic petroleum resin. Examples of the C5-C9 resin include petroleum-derived C5-C 11 Examples of the solid polymers include those obtained by polymerizing the fraction using a Friedel-Crafts catalyst such as AlCl3 or BF3, and more specifically, copolymers mainly composed of styrene, vinyltoluene, α-methylstyrene, indene, etc. As the C5-C9 resin, a resin with a small amount of C9 or more components is preferred from the viewpoint of compatibility with the rubber component. Here, "a small amount of C9 or more components" means that the amount of C9 or more components in the total amount of the resin is less than 50 mass%, preferably 40 mass% or less.

[0062] The C9 resin refers to a C9 synthetic petroleum resin, for example, a solid polymer obtained by polymerizing a C9 fraction using a Friedel-Crafts catalyst such as AlCl3 or BF3. Examples of the C9 resin include copolymers mainly composed of indene, α-methylstyrene, vinyltoluene, etc.

[0063] The cyclopentadiene resin refers to a resin containing a unit derived from a cyclopentadiene monomer as a monomer unit. Examples of the cyclopentadiene resin include a homopolymer of a cyclopentadiene monomer, a copolymer of two or more cyclopentadiene monomers, and a copolymer of a cyclopentadiene monomer and another monomer. Here, examples of the cyclopentadiene monomer include cyclopentadiene, dicyclopentadiene, and tricyclopentadiene, and among these, dicyclopentadiene is preferred, that is, the cyclopentadiene resin is preferably a dicyclopentadiene resin. The dicyclopentadiene resin refers to a resin obtained by polymerizing dicyclopentadiene using a Friedel-Crafts catalyst such as AlCl3 or BF3. Examples of dicyclopentadiene resins include homopolymers of dicyclopentadiene, copolymers of dicyclopentadiene and aromatic monomers, and copolymers of dicyclopentadiene and C9 fractions (vinyl toluene, indene, etc.).

[0064] The aromatic resin refers to a resin containing a unit derived from an aromatic monomer as a monomer unit. Examples of the aromatic resin include a homopolymer of an aromatic monomer, a copolymer of two or more aromatic monomers, and a copolymer of an aromatic monomer and another monomer. Examples of the aromatic monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, and p-phenylstyrene; phenolic monomers such as phenol, alkylphenol, and alkoxyphenol; and naphthol monomers such as naphthol, alkylnaphthol, and alkoxynaphthol.

[0065] The other resin preferably has a softening point of 30° C. or higher, more preferably 60° C. or higher, more preferably 80° C. or higher, more preferably higher than 110° C., more preferably 116° C. or higher, more preferably 120° C. or higher, more preferably 123° C. or higher, and even more preferably 127° C. or higher. From the viewpoint of processability, the resin preferably has a softening point of 160° C. or lower, more preferably 150° C. or lower, more preferably 145° C. or lower, more preferably 141° C. or lower, and even more preferably 136° C. or lower.

[0066] As the other resins, commercially available products can be used, and examples of commercially available resins that can be used include products from ENEOS Corporation, Arakawa Chemical Industries, Ltd., ExxonMobil Corporation, Clayton, Yasuhara Chemical Co., Ltd., Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Clayton Polymers, Nippon Paint Chemical Co., Ltd., Nippon Shokubai Co., Ltd., Taoka Chemical Co., Ltd., and the like.

[0067] The content of the other resin is not particularly limited, and can be appropriately adjusted depending on, for example, the tire category to which the rubber composition is applied, the target performance, etc. For example, the content of the other resin is preferably in the range of 5 to 100 parts by mass, and more preferably in the range of 10 to 60 parts by mass, relative to 100 parts by mass of the rubber component (A).

[0068] (silica) The rubber composition of the present embodiment may contain silica. Examples of the silica include wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate, etc., and among these, wet silica is preferred because it has a large number of silanol groups. These silicas may be used alone or in combination of two or more. As the silica, a commercially available product may be used, and examples of the commercially available silica include products from Tosoh Silica Corporation, Evonik, Solvay, Solvay Japan, Tokuyama Corporation, etc.

[0069] As the silica, silica derived from silicic acid plants is preferred from the viewpoint of reducing environmental load. The silicic acid plants are present, for example, in mosses, ferns, horsetails, Cucurbitaceae, Urticaceae, and Gramineae plants. Among these plants, Gramineae plants are preferred. In addition, the Gramineae plants include rice, bamboo grass, sugarcane, and the like, among which rice is preferred. Since rice is widely cultivated for food, it can be procured locally in a wide area, and since rice husks are generated in large quantities as industrial waste, it is easy to secure the amount. Therefore, from the viewpoint of easy availability, silica derived from rice husks (hereinafter also referred to as "rice husk silica") is particularly preferred as silica. By using the rice husk silica, rice husks that become industrial waste can be effectively utilized, and since the raw material can be procured locally near the tire manufacturing plant, the energy and cost of transportation and storage can be reduced, which is environmentally preferable from various viewpoints. The rice husk silica may be a powder of rice husk charcoal obtained by carbonizing rice husks by heating, or may be precipitated silica produced by a wet method using an alkali silicate aqueous solution, which is prepared by extracting rice husk ash generated when rice husks are burned as fuel in a biomass boiler with an alkali and extracting the rice husk ash with an alkali silicate aqueous solution. The method for producing the rice husk charcoal is not particularly limited, and various known methods can be used. For example, rice husks can be pyrolyzed by steaming them in a kiln to obtain rice husk charcoal. The rice husk charcoal thus obtained is pulverized using a known pulverizer (for example, a ball mill), and then sorted and classified into a predetermined particle size range to obtain rice husk charcoal powder. The rice husk-derived precipitated silica can be produced by the method described in JP 2019-38728 A. Further examples of the silica include silica produced by recycling silicon components from scraps of silicon wafers, which are raw materials for semiconductors, glass bottles, etc.

[0070] The silica has a nitrogen adsorption specific surface area (N2SA) of 50 m 2 / g or more, and 2 / g or more is more preferable, and 150m 2 / g or more is more preferable, and 2 / g or less, and2 / g or less is more preferable, 2 / g or less is more preferable, 2 It is even more preferable that the molecular weight is not more than 1 / g. In this specification, the nitrogen adsorption specific surface area (N2SA) of silica is a value measured by the BET method in accordance with ASTM D3037-93.

[0071] The content of the silica is, for example, preferably 1 part by mass or more, more preferably 3 parts by mass or more, and is preferably 40 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, based on 100 parts by mass of the rubber component (A).

[0072] (Silane coupling agent) When the rubber composition of the present embodiment contains silica, in order to improve the effect of the silica, the rubber composition preferably contains a silane coupling agent. Examples of the silane coupling agent include bis(3-triethoxysilylpropyl)tetrasulfide, bis(3-triethoxysilylpropyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyltetrasulfide, 3-triethoxysilylpropyl-N, Examples of the silane coupling agent include N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropyl benzothiazolyl tetrasulfide, 3-triethoxysilylpropyl benzothiazolyl tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis(3-diethoxymethylsilylpropyl)tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, dimethoxymethylsilylpropyl benzothiazolyl tetrasulfide, etc. As the silane coupling agent, a commercially available product can be used, and examples of the commercially available silane coupling agent include products from Evonik, Momentive, Shin-Etsu Silicone Co., Ltd., Dow Corning Toray Co., Ltd., Tokyo Chemical Industry Co., Ltd., and Azumax Co., Ltd. These silane coupling agents may be used alone or in combination of two or more.

[0073] The content of the silane coupling agent is, for example, preferably 1 part by mass or more, more preferably 6 parts by mass or more, and even more preferably 8 parts by mass or more, relative to 100 parts by mass of the silica, and is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, even more preferably 12 parts by mass or less, and even more preferably 10 parts by mass or less.

[0074] Bioethanol can also be used as a raw material for the silane coupling agent. Bioethanol is produced mainly using sugars and / or cellulose as biological resources, and other biological resources such as proteins, lipids, and amino acids cannot be effectively utilized. Furthermore, sugars compete with food, and excessive use of cellulose leads to deforestation. Therefore, it is preferable to use multiple types of monomer components derived from biological resources as the monomer components derived from the biological resources, or to use a monomer component derived from a biological resource, a monomer component derived from a renewable resource, and a monomer component derived from a fossil resource in combination, depending on the supply status of various biological resources, the supply status of renewable resources, the supply status of fossil resources, and market demands (for example, the demand for biomass resources as food). This makes it possible to effectively utilize a wide range of biological resources and renewable resources such as sugars, proteins, and lipids without relying on one type of biological resource, and also to consider the environment depending on the situation during production.

[0075] (Carbon Black) The rubber composition of the present embodiment preferably contains carbon black. As the carbon black, carbon black derived from plants and carbon black obtained by recycling (i.e., recycled carbon black) are particularly preferable. Examples of carbon black derived from plants include those derived from castor oil and rosin oil. Examples of recycled carbon black include carbon black obtained by decomposition (particularly thermal decomposition) of crosslinked rubber products such as used tires, and carbon black obtained from waste oil.

[0076] The grade of the carbon black is not particularly limited, and examples thereof include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. Commercially available carbon blacks can be used, and examples of the commercially available carbon blacks include products from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Nippon Steel Carbon Co., Ltd., and Birla Carbon Co., Ltd. These carbon blacks may be used alone or in combination of two or more.

[0077] The nitrogen adsorption specific surface area (N2SA) of the carbon black is not particularly limited and can be appropriately adjusted depending on, for example, the tire category to which it is applied, the target performance, etc. For example, the nitrogen adsorption specific surface area (N2SA) of carbon black is 20 m 2 / g or more is preferable, and 50m 2 / g or more is more preferable, and 70m 2 / g or more is more preferable, and 90m 2 / g or more is more preferable, and 200m 2 / g or less is preferable, and 150m 2 / g or less is more preferable, and 130m 2 / g or less is more preferable. In this specification, the nitrogen adsorption specific surface area (N2SA) of carbon black is determined in accordance with JIS K 6217-2:2017 (ISO 4652:2012).

[0078] The carbon black content is not particularly limited and can be appropriately adjusted depending on, for example, the target performance. For example, the carbon black content is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and even more preferably 40 parts by mass or more, based on 100 parts by mass of the rubber component (A). The carbon black content is preferably 70 parts by mass or less, and more preferably 65 parts by mass or less, based on 100 parts by mass of the rubber component (A).

[0079] (liquid softener) The rubber composition of the present embodiment may contain a liquid softener. Here, the "liquid softener" is a compounding agent that is liquid at 25°C (room temperature) and has the effect of softening the rubber composition. The liquid softener is not particularly limited, and examples thereof include oil and liquid polymer, among which oil is preferable. These liquid softeners may be used alone or in combination of two or more.

[0080] The oil is a general term for the extender oil contained in the rubber component and the liquid oil added as a compounding agent of the rubber composition, and examples thereof include vegetable oil, process oil, oil obtained by recycling vegetable oil or process oil, or a mixture thereof. From the viewpoint of reducing the environmental load, the oil is preferably vegetable oil or oil obtained by recycling. Examples of the vegetable oil include palm oil, castor oil, cottonseed oil, soybean oil, linseed oil, rapeseed oil, coconut oil, peanut oil, pine oil, pine tar, tall oil, corn oil, rice oil, safflower oil, sesame oil, olive oil, sunflower oil, palm kernel oil, camellia oil, jojoba oil, macadamia nut oil, tung oil, coconut oil, etc. Examples of the process oil include paraffin-based process oil, aromatic process oil, naphthene-based process oil, etc. The oil may be a commercially available product, and examples of the commercially available oil include products from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, Orisoi Co., Ltd., H&R Corporation, Toyokuni Oil Mills Co., Ltd., and Nisshin Oillio Group Co., Ltd. These oils may be used alone or in combination of two or more.

[0081] The liquid polymer is preferably a liquid diene polymer. Examples of the liquid diene polymer include liquid styrene-butadiene copolymer (liquid SBR), liquid polybutadiene (liquid BR), liquid polyisoprene (liquid IR), liquid styrene-isoprene copolymer (liquid SIR), liquid styrene-butadiene-styrene block copolymer (liquid SBS block polymer), liquid styrene-isoprene-styrene block copolymer (liquid SIS block polymer), liquid polyfarnesene, and liquid farnesene-butadiene copolymer. These liquid polymers may be hydrogenated, or the terminals or main chains may be modified with functional groups (polar groups). These liquid polymers may be used alone or in combination of two or more.

[0082] The content of the liquid softener is not particularly limited, and can be appropriately adjusted depending on, for example, the tire category to which the softener is applied, the target performance, etc. For example, the content of the liquid softener is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and is preferably 100 parts by mass or less, more preferably 70 parts by mass or less, even more preferably 50 parts by mass or less, and even more preferably 30 parts by mass or less, relative to 100 parts by mass of the rubber component (A).

[0083] (Anti-aging agent) The rubber composition of the present embodiment may contain an antioxidant, such as N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine, 2,2,4-trimethyl-1,2-dihydroquinoline polymer (TMDQ), 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline (AW), and 6-anilino-2,2,4-trimethyl-1,2-dihydroquinoline. As the antiaging agent, commercially available products can be used, and examples of the commercially available antiaging agent include products from Ouchi Shinko Chemical Industry Co., Ltd., Sumitomo Chemical Co., Ltd., Seiko Chemical Co., Ltd., Flexis Co., Ltd., etc. These antiaging agents may be used alone or in combination of two or more.

[0084] The content of the antiaging agent is not particularly limited, and can be appropriately adjusted depending on, for example, the tire category to which the antiaging agent is applied, the target performance, etc. For example, the content of the antiaging agent is preferably 1 part by mass or more, more preferably 1.5 parts by mass or more, and even more preferably 2 parts by mass or more, and is preferably 12 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 8 parts by mass or less, relative to 100 parts by mass of the rubber component (A).

[0085] (Stearic acid) The rubber composition of the present embodiment may contain stearic acid. Commercially available stearic acid may be used, and examples of the commercially available stearic acid include products from NOF Corp., Kao Corp., Fujifilm Wako Pure Chemical Corp., Chiba Fatty Acid Corp., etc. These commercially available stearic acid products may be used alone or in combination of two or more.

[0086] The content of the stearic acid is not particularly limited, and can be appropriately adjusted depending on, for example, the tire category to which the rubber composition is applied, the target performance, etc. For example, the content of the stearic acid is preferably 0.5 parts by mass or more and preferably 10 parts by mass or less, and more preferably 6 parts by mass or less, based on 100 parts by mass of the rubber component (A).

[0087] (Zinc Oxide) The rubber composition of the present embodiment may contain zinc oxide (zinc white). The zinc oxide is preferably zinc oxide obtained by recycling. Commercially available zinc oxide may be used, and examples of the commercially available zinc oxide include products from Hakusui Tech Co., Ltd., Seido Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., and the like. These commercially available zinc oxide products may be used alone or in combination of two or more. The zinc used for the zinc oxide may be not only zinc bullion, but also zinc obtained from recycled zinc or zinc dross.

[0088] The content of the zinc oxide is not particularly limited, and can be appropriately adjusted depending on, for example, the tire category to which the rubber composition is applied, the target performance, etc. For example, the content of the zinc oxide is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and is preferably 10 parts by mass or less, more preferably 6 parts by mass or less, per 100 parts by mass of the rubber component (A).

[0089] (sulfur) The rubber composition of the present embodiment preferably contains sulfur. The sulfur may be derived from fossil resources, recycled resources, or materials derived from biological resources. From the viewpoint of reducing the environmental load, it is particularly preferable to use sulfur obtained from waste derived from biological resources. Examples of a method for obtaining sulfur from waste derived from biological resources include the method described in the above-mentioned Japanese Patent Application No. 2022-140390. In addition, the sulfur may be powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, soluble sulfur, etc., which are generally used as crosslinking agents in the rubber industry. As the sulfur, commercially available products can be used, and examples of commercially available sulfur products include products from Tsurumi Chemical Industry Co., Ltd., Hosoi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemical Industry Co., Ltd., Flexis Co., Ltd., etc. These sulfurs may be used alone or in combination of two or more types.

[0090] The sulfur content is not particularly limited, and can be appropriately adjusted depending on, for example, the tire category to which the rubber composition is applied, the target performance, etc. For example, the sulfur content is preferably 0.3 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 0.8 parts by mass or more, and is preferably 8 parts by mass or less, and more preferably 5 parts by mass or less, relative to 100 parts by mass of the rubber component (A).

[0091] (Vulcanization accelerator) The rubber composition of the present embodiment preferably contains a vulcanization accelerator. The vulcanization accelerator may be derived from fossil resources, recycled resources, or biological resources, but is preferably derived from biological resources from the viewpoint of reducing environmental load. The vulcanization accelerator derived from biological resources can be obtained by the method disclosed in, for example, JP-A-2005-139239. Examples of the vulcanization accelerator include sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N,N-dicyclohexyl-2-benzothiazolylsulfenamide, N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-oxyethylene-2-benzothiazolesulfenamide, and N,N'-diisopropyl-2-benzothiazolesulfenamide; 1,3-diphenylguanidine (DPG), 1,3-diphenylguanidine (DPG), and 1,3-diphenylguanidine (DPG). Examples of the vulcanization accelerator include guanidine-based vulcanization accelerators such as o-tolylguanidine and o-tolylbiguanidine; thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole (M) and di-2-benzothiazolyl disulfide (MBTS, DM); and thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrastearylthiuram disulfide, tetrabenzylthiuram disulfide (TBzTD), and tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N). Commercially available products can be used as the vulcanization accelerator, and examples of the commercially available vulcanization accelerators include products from Ouchi Shinko Chemical Industry Co., Ltd. and Sumitomo Chemical Co., Ltd. These vulcanization accelerators may be used alone or in combination of two or more.

[0092] The content of the vulcanization accelerator is not particularly limited, and can be appropriately adjusted depending on, for example, the tire category to which the rubber is applied, the target performance, etc. For example, the content of the vulcanization accelerator is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, and is preferably 8 parts by mass or less, more preferably 6 parts by mass or less, and even more preferably 5.5 parts by mass or less, relative to 100 parts by mass of the rubber component (A).

[0093] (others) In addition to the above-mentioned components, the rubber composition of the present embodiment may further contain various additives commonly used in the tire industry, such as fillers such as calcium carbonate, talc, alumina, clay, aluminum hydroxide, and mica; organic peroxides; etc. The content of these additives is not particularly limited and can be appropriately adjusted depending on, for example, the tire category to which the rubber composition is applied, the target performance, etc., and is preferably in the range of 0.1 to 200 parts by mass per 100 parts by mass of the rubber component (A).

[0094] (Method of manufacturing rubber composition) The method for producing the rubber composition of the present embodiment is not particularly limited, but for example, the rubber composition can be produced by blending at least one resin component (B) selected from a terpene-based resin and a rosin-based resin, and various other components appropriately selected as necessary, with the rubber component (A) containing the isoprene-based rubber, and kneading, heating, extruding, etc. The obtained rubber composition can be vulcanized to produce a vulcanized rubber.

[0095] The conditions for the kneading are not particularly limited, and various conditions such as the input volume of the kneading device, the rotation speed of the rotor, the ram pressure, the kneading temperature, the kneading time, the type of the kneading device, etc. can be appropriately selected depending on the purpose. Examples of the kneading device include a Banbury mixer, an intermix, a kneader, a roll, etc. that are usually used for kneading rubber compositions.

[0096] The conditions of the heat-in are not particularly limited, and various conditions such as the heat-in temperature, heat-in time, heat-in equipment, etc. can be appropriately selected depending on the purpose. Examples of the heat-in equipment include a heat-in roller machine usually used for heat-in of a rubber composition.

[0097] The extrusion conditions are not particularly limited, and various conditions such as extrusion time, extrusion speed, extrusion device, and extrusion temperature can be appropriately selected depending on the purpose. Examples of the extrusion device include an extruder that is usually used for extruding a rubber composition. The extrusion temperature can be appropriately determined.

[0098] The vulcanization apparatus, method, conditions, etc. are not particularly limited and can be appropriately selected according to the purpose. As the vulcanization apparatus, a molding vulcanizer using a mold used for vulcanizing a rubber composition can be mentioned. As the vulcanization condition, the temperature is, for example, about 100 to 190°C.

[0099] (Metal Cord) The metal cord in the metal cord-rubber composite of this embodiment may be, for example, a single metal wire (metal steel wire) or a plurality of metal wires twisted together. The metal wire is not particularly limited, but examples thereof include wire materials such as iron, steel (stainless steel), lead, aluminum, copper, brass, bronze, Monel metal alloy, nickel, and zinc.

[0100] In the metal cord-rubber composite of this embodiment, it is also preferable that the metal cord is a monofilament (a single metal wire) that is drawn in parallel without being twisted with each other.

[0101] The filament (metal wire) constituting the metal cord has a diameter of X (mm) and a tensile strength of Y (MPa) that satisfies the following formula: 4000-2000X≦Y≦4500-2000X It is preferable that the above formula is satisfied. By using a filament that satisfies the above formula, the strength of the metal cord-rubber composite can be further improved, the plunger level can be improved, and the cut resistance of the tire can be supplemented. Here, the tensile strength of the filament is determined in accordance with the provisions of ISO 17832:2009.

[0102] In the filaments constituting the metal cord, the hardness of the surface layer of the filament is preferably 90 to 110% of the hardness of the inner layer, and particularly preferably 100%, from the viewpoint of fatigue resistance. The hardness can be measured, for example, by Vickers hardness. The surface layer of the filament means a layer from the outermost surface to a depth of 0.01 mm, and the area inside is the inner layer of the filament. The hardness can be measured in a region 0.005 mm deep from the outermost surface for the surface layer, and 0.04 mm deep for the inner layer.

[0103] The method for producing the filaments constituting the metal cord is not particularly limited. The filaments may be obtained, for example, by refining iron ore and drawing the wire, by refining scrap iron and drawing the wire, or by recycling steel extracted from tires.

[0104] The metal wire preferably has a plating layer applied to its surface (circumferential surface) by a conventional method. The plating layer is not particularly limited, but examples thereof include a zinc plating layer, a copper plating layer, and a brass plating layer. Among these, a brass plating layer is preferred from the viewpoint of adhesion to the rubber composition and the formation of a suitable rubber-metal adhesive layer. That is, the metal wire is preferably a metal wire having a brass plating applied to its peripheral surface. The thickness of the brass plating layer is not particularly limited, but is generally, for example, 100 to 300 nm.

[0105] When the metal cord is a single metal wire having a brass plating applied to its circumferential surface, or a metal cord formed by twisting a plurality of metal wires, the composition of the brass plating (bulk brass plating constituting the brass plating layer) is preferably 40-80 mass% Cu (copper) and 20-60 mass% Zn (zinc). In this case, the cord processability and adhesion to the rubber composition can be improved. From the same viewpoint, the composition of the brass plating is more preferably 55-70 mass% Cu and 30-45 mass% Zn.

[0106] The surface of the metal cord preferably contains N atoms of 2 atomic % or more and 60 atomic % or less (more specifically, 2.0 atomic % or more and 60.0 atomic % or less) and has a Cu / Zn ratio of 1 or more and 4 or less (more specifically, 1.0 or more and 4.0 or less). By making the N atoms on the surface of the metal cord 2 atomic % or more, the adhesion between the rubber composition and the metal cord can be improved in combination with the action of the resin component (B), and by making it 60 atomic % or less, the initial adhesion between the rubber composition and the metal cord can be suppressed from deteriorating in combination with the action of the resin component (B). In addition, by making the Cu / Zn ratio on the surface of the metal cord 1 or more, the adhesion between the rubber composition and the metal cord can be improved in combination with the action of the resin component (B), and by making it 4 or less, the initial adhesion between the rubber composition and the metal cord can be suppressed from deteriorating in combination with the action of the resin component (B). From the same viewpoint, the N atoms on the surface of the metal cord are more preferably contained in a range of 2.1 atomic % or more and 55.0 atomic % or less. From the same viewpoint, the Cu / Zn ratio on the surface of the metal cord is more preferably 1.1 or more and 3.5 or less.

[0107] The N (nitrogen) atoms on the surface of the metal cord can be adjusted to 2 atomic % or more and 60 atomic % or less by suitably combining, for example, a treatment with a triazole compound (rust inhibitor), specifically, a surface treatment such as contacting with an aqueous solution of a triazole compound (aqueous triazole solution). The Cu / Zn ratio on the surface of the metal cord can be adjusted to 1 or more and 4 or less by combining, for example, a surface treatment with an acidic buffer solution and a treatment with a triazole compound, and adjusting the pH of the acidic buffer solution or the concentration of the aqueous solution of the triazole compound. In this regard, the lower the pH of the acidic buffer solution, the higher the Cu / Zn ratio on the surface of the metal cord can be.

[0108] The pH of the acidic buffer solution is preferably 5.0 to 7.2. If the pH is less than 5.0, it is difficult or impossible to achieve a Cu / Zn ratio of 4 or less, and if the pH is more than 7.2, it is difficult or impossible to achieve a Cu / Zn ratio of 1 or more. Examples of the acidic buffer solution include acetate buffer solution, phosphate buffer solution, and citrate buffer solution, and among these, acetate buffer solution is preferred. The surface treatment time with the acidic buffer solution can be, for example, 0.5 to 20 seconds when an acetate buffer solution having a pH of 5.0 to 7.2 is used. The triazole compound may be, for example, at least one triazole compound selected from 1,2,4-triazole, 1,2,3-triazole, 3-amino-1,2,4-triazole, 4-amino-1,2,4-triazole, benzotriazole, tolyltriazole, and 3-mercapto-1,2,4-triazole. Among these, it is more preferable to use at least one triazole compound selected from 1,2,4-triazole, 1,2,3-triazole, 3-amino-1,2,4-triazole, and 4-amino-1,2,4-triazole. The concentration of the triazole aqueous solution is preferably 0.01 to 20 g / L. The treatment time with the triazole compound varies depending on the concentration, but can be, for example, 0.1 to 30 seconds.

[0109] More preferably, the metal cord is a metal cord that has been surface-treated with a buffer solution having a pH of 5.0 to 7.2 and treated with at least one triazole compound selected from 1,2,4-triazole, 1,2,3-triazole, 3-amino-1,2,4-triazole, 4-amino-1,2,4-triazole, benzotriazole, tolyltriazole, and 3-mercapto-1,2,4-triazole. In this case, the adhesion between the rubber composition and the metal cord can be improved, and deterioration of the initial adhesion between the rubber composition and the metal cord can be suppressed.

[0110] In this specification, the term "surface" refers to a surface region of a metal wire such as a steel wire, which is located to a depth of 5 (nm) on the radially inner side. The measurement of N atoms on the surface of the metal cord and the measurement of the Cu / Zn ratio are performed by measuring the surface of the metal cord after the metal cord is obtained and, if necessary, after cleaning and drying, and before it is coated with a rubber composition. In addition, in this specification, the measurement of N atoms on the surface of the metal cord refers to measurement of N atoms on the surface of the metal cord measured by X-ray photoelectron spectroscopy (XPS), and the measurement of the Cu / Zn ratio on the surface of the metal cord refers to measurement of the Cu / Zn ratio on the surface of the metal cord by the photoelectron spectroscopy.

[0111] Next, the above-mentioned metal wire will be described in more detail by taking a steel wire as an example. The steel wire is a linear metal mainly composed of steel, i.e., iron (the mass of iron with respect to the total mass of the metal steel wire exceeds 50 mass%). The metal may contain metals other than the above-mentioned iron. From the viewpoint of workability and durability, the wire diameter of the steel wire is preferably 0.1 mm to 5.5 mm, more preferably 0.15 mm to 5.26 mm. Here, the wire diameter of the steel wire refers to the longest length between two points on the circumference of the cross section perpendicular to the axis of the steel wire. The cross section perpendicular to the axis of the steel wire is not particularly limited and may be elliptical, rectangular, triangular, polygonal, etc., but is generally circular. When the steel wires are twisted together to form a steel cord, which is a metal reinforcing cord, for use in a tire carcass or belt, the cross section of the steel wire is preferably circular and the wire diameter is preferably 0.1 mm to 0.5 mm. When the steel cord is used in a tire bead core, the cross section is preferably circular and the wire diameter is preferably 1 mm to 1.5 mm.

[0112] As the metal cord used in this embodiment, for example, a plurality of metal wires such as the steel wires having the circumferential surface plated with brass can be twisted together to obtain a metal cord made of steel cords by a conventional method. The twisting can be, for example, a 1×N structure, a 1+N structure, an M+N structure, or the like. In addition, as the metal cord, a multi-twisted metal cord can be used in which a plurality of the twisted steel cords are further twisted together to form Q core strands and P sheath strands. These metal cords made of metal wires such as steel wires are suitable for reinforcing rubber articles, and are preferably used as at least one type selected from belt cords, carcass cords, and bead cords for tires.

[0113] (Manufacturing of metal cord-rubber composites) The metal cord-rubber composite of this embodiment can be obtained by coating a metal cord with the above-mentioned rubber composition. The method of coating the metal cord with the rubber composition is not particularly limited. For example, a metal cord, particularly a metal cord that has been subjected to various surface treatments, can be washed by a conventional method as necessary, and then bonded to the rubber composition of this embodiment, to produce a metal cord-rubber composite. The adhesion between the metal cord and the rubber composition of this embodiment can be performed, for example, by crosslinking and bonding the metal cord and the rubber composition under pressure and heat.

[0114] Specifically, for example, a predetermined number of metal cords are arranged in parallel at a predetermined interval, and the metal cords are coated from above and below with uncrosslinked rubber sheets of about 0.5 mm thickness made of the rubber composition of this embodiment to obtain a precursor (metal cord-uncrosslinked rubber composite). Next, the obtained precursor is crosslinked to obtain a metal cord-rubber composite. In the above crosslinking, for example, a vulcanizing agent can be used as a crosslinking agent. In addition, as crosslinking conditions, the crosslinking pressure is preferably 2 MPa to 15 MPa, more preferably 2 MPa to 5 MPa. In addition, the crosslinking temperature is preferably 120 to 200°C, more preferably 130 to 170°C. Furthermore, the crosslinking time is not particularly limited, but is preferably 3 minutes to 60 hours.

[0115] (Uses of metal cord-rubber composites) The metal cord-rubber composite of the present embodiment is preferably used as a reinforcing material for rubber articles that require particular strength, such as various automobile tires, crawlers, hoses, etc. In particular, it is preferably used as a reinforcing member for belts, carcass plies, wire chafers, etc. of various automobile radial tires.

[0116] When a tire is manufactured using the metal cord-rubber composite of this embodiment, the tire can be manufactured by a normal method using the above-mentioned metal cord-rubber composite. In general, a rubber composition containing various components is processed into each member in the uncrosslinked stage, and is attached and molded in a tire molding machine by a normal method to mold a raw tire. This raw tire is heated and pressurized in a crosslinking machine to manufacture a tire. For example, the rubber composition of this embodiment is kneaded, and then the metal cord is rubber-coated with the obtained rubber composition, and an uncrosslinked belt layer, an uncrosslinked carcass, and other uncrosslinked members are laminated, and the uncrosslinked laminate is crosslinked to obtain a tire. The gas to be filled into the tire may be normal air, air with an adjusted oxygen partial pressure, or an inert gas such as nitrogen, argon, helium, etc. The tire of this embodiment is preferably a pneumatic tire, and the gas to be filled into the pneumatic tire may be normal air or air with an adjusted oxygen partial pressure, or an inert gas such as nitrogen, argon, helium, etc.

[0117] A tire manufactured using the metal cord-rubber composite of this embodiment (i.e., a tire equipped with the metal cord-rubber composite of this embodiment) may include a belt reinforcing layer on the tire radially outer side of the belt. The belt reinforcing layer may be, for example, a member formed by covering reinforcing cords (organic fiber cords) arranged substantially parallel to the tire circumferential direction (for example, at an angle of 0 to 5° with respect to the tire circumferential direction) with a reinforcing layer rubber (elastomer). The belt reinforcing layer may be formed by continuously winding a narrow strip prepared by covering an organic fiber cord with an elastomer in a spiral shape in the tire circumferential direction.

[0118] The organic fiber cord applied to the belt reinforcing layer may be, for example, an organic fiber cord having a breaking strength of 6.5 cN / dtex or more, a breaking elongation of 10% or more, and an elastic modulus at 7% elongation of 6.0 mN / (dtex·%) or more.

[0119] An organic fiber cord having a breaking strength of 6.5 cN / dtex or more, a breaking elongation of 10% or more, and an elastic modulus at 7% elongation of 6.0 mN / (dtex·%) or more has high strength at break, large elongation at break, and a high elastic modulus at 7% elongation. Therefore, when an organic fiber cord with such physical properties is used in a belt reinforcing layer, it is possible to improve the steering stability of the tire while ensuring the plunger durability of the tire.

[0120] The material of the organic fiber cord is not particularly limited, and examples thereof include polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyethylene furan dicarboxylate (PEF); nylons such as 6-nylon, 6,6-nylon, 4,6-nylon, and 4,10-nylon; and celluloses such as rayon and lyocell. Among these, polyethylene terephthalate is preferred, that is, the organic fiber cord as the reinforcing material of the belt reinforcing layer is preferably a cord made of polyethylene terephthalate (hereinafter, sometimes simply referred to as "polyethylene terephthalate cord"). The polyethylene terephthalate cord has higher rigidity than commonly used nylon cords and is excellent in improving the plunger durability and steering stability of the tire. In addition, the raw material of the organic fiber cord is not particularly limited, and may be derived from synthetic products, biological products, mechanical recycling derived from crushing, melting, and re-spinning PET products such as PET bottles, or chemical recycling derived from depolymerizing and repolymerizing PET products such as PET bottles. EXAMPLES

[0121] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples and can be modified as appropriate without departing from the gist of the present invention.

[0122] Three types of unvulcanized rubber compositions having the formulations shown in Table 1 were prepared.

[0123] (Sustainable material ratio) The sustainable material ratio (%) of each unvulcanized rubber composition was calculated using the following formula. The results are shown in Table 1. Sustainable material ratio = Total sustainable materials (B in the table) / Total of all materials (A in the table) x 100

[0124] (Rubber-rubber tackiness) Each unvulcanized rubber composition was passed through a roll and wound around it for 2 minutes, after which a rubber piece was made into a sheet shape. After 5 days, the rubber sheet was pressed and the adhesive strength between the rubber pieces was measured using a Picmatak Tester (manufactured by Toyo Seiki Co., Ltd.). The higher the adhesive strength, the more likely it is that problems such as air getting between the rubber parts after molding can be suppressed, and the better the workability is. Each example was then indexed with the measured value of Reference Example 1 set at 100, and evaluated according to the following criteria. The results are shown in Table 1. Less than 100: Deterioration 100~105: Equivalent 106 or more: Good

[0125] (Scorch resistance) For each unvulcanized rubber composition, the time (scorch time) until the torque increased by 2.0 points from the torque Min was measured using an RPA (manufactured by Alpha Technology Co., Ltd.) at 130°C, 1 Hz, and 100% strain. The longer the time, the more the rubber scorch can be suppressed and the better the workability. Each example was indexed with the measured value of Reference Example 1 set at 100, and evaluated according to the following criteria. The results are shown in Table 1. Less than 100: Deterioration 100~105: Equivalent 106 or more: Good

[0126] [Table 1]

[0127] *1 Butadiene rubber: ENEOS Materials Corporation, product name "BR01" *2 Carbon black: FEF grade *3 Resin 1: SUMITOMO BAKELITE EUROPE, product name "DUREZ 19900" (petroleum-derived resin) *4 Resin 2: Kraton Corporation, product name "SYLVATRAXX2097" (rosin-based resin) *5 Other chemicals: Sulfur, vulcanization accelerator, antioxidant, wax, oil, stearic acid, zinc oxide. The comparative examples and examples all contain the same types of chemicals in the same ratios.

[0128] From Table 1, it can be seen that the rubber compositions of the examples are excellent in rubber-rubber tackiness and scorch resistance, that is, excellent in workability including rubber fading and moldability, etc. Furthermore, from Table 1, it can be seen that metal cord-rubber composites using such rubber compositions can contribute to improving sustainability. [Industrial Applicability]

[0129] According to the present invention, it is possible to provide a metal cord-rubber composite in which the rubber composition used is excellent in workability, including rubber fading and moldability, and which can contribute to improving sustainability.

Claims

1. A metal cord-rubber composite obtained by coating a metal cord with a rubber composition, The metal cord-rubber composite, characterized in that the rubber composition contains a rubber component (A) containing an isoprene-based rubber, and at least one resin component (B) selected from a terpene-based resin and a rosin-based resin.

2. 2. The metal cord-rubber composite according to claim 1, wherein the content of the resin component (B) in the rubber composition is 10 parts by mass or less per 100 parts by mass of the rubber component (A).

3. 3. The metal cord-rubber composite according to claim 1, wherein the surface of the metal cord contains N atoms in an amount of 2 atomic % or more and 60 atomic % or less, and has a Cu / Zn ratio of 1 or more and 4 or less.

4. The metal cord is a metal cord made of a single metal wire having a circumferential surface plated with brass, or a metal cord made of a plurality of twisted metal wires, and the composition of the brass plating is Cu: 40 to 80 mass % and Zn: 20 to 60 mass %. The metal cord-rubber composite according to claim 1 or 2.

5. The metal cord-rubber composite according to claim 1 or 2, wherein the metal cord is a metal cord that has been subjected to a surface treatment with a buffer solution having a pH of 5.0 to 7.2 and a treatment with at least one triazole compound selected from 1,2,4-triazole, 1,2,3-triazole, 3-amino-1,2,4-triazole, 4-amino-1,2,4-triazole, benzotriazole, tolyltriazole, and 3-mercapto-1,2,4-triazole.

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