Tire rubber composition and tire

Abstract

The present invention addresses the problem of providing a rubber composition for tires that achieves both wear resistance and wet performance while ensuring low fuel consumption. A means for solving the problem is a rubber composition for tires, characterized by containing a rubber component and a thermoplastic resin, the rubber component containing a copolymer of cyclopentene and a norbornene-based compound represented by the following general formula (1) [where: R1 to R4 each independently represent a hydrogen atom, a hydrocarbon group having 1-20 carbon atoms, or a substituent containing a halogen atom, a silicon atom, an oxygen atom, or a nitrogen atom; R2 and R3 may be bonded to each other to form a ring; and m represents an integer of 0-2].

Description

Rubber composition for tires and tires

[0001] This invention relates to a rubber composition for tires and a tire.

[0002] In line with the growing global concern over environmental issues and the resulting global movement towards carbon dioxide emission regulations, there is a growing demand for more fuel-efficient automobiles. To meet this demand, tire performance is also required to improve fuel efficiency (i.e., reduce losses). Patent documents 1 and 2 below disclose rubber compounding for passenger car tires and heavy-duty truck and bus tires, which include a specific long-chain branched cyclopentene ring-opening rubber (LCB-CPR). These rubber compoundings are said to be effective in reducing tire rolling resistance, improving wet skid resistance, and improving wear resistance.

[0003] International Publication No. 2021 / 178233, International Publication No. 2021 / 178235

[0004] However, the inventors have found that even with the technologies described in Patent Documents 1 and 2, it is difficult to achieve both low fuel consumption and wear resistance and wet grip (WET) performance simultaneously, and there is still room for improvement.

[0005] Therefore, the present invention aims to solve the problems of the above-mentioned prior art and provide a tire rubber composition that achieves both wear resistance and wet performance while ensuring low fuel consumption. Furthermore, the present invention aims to provide a tire that achieves both wear resistance and wet performance while ensuring low fuel consumption.

[0006] The gist of the rubber composition for tires and the tire of the present invention, which solves the above problems, is as follows.

[0007] [1] comprising a rubber component and a thermoplastic resin, wherein the rubber component comprises cyclopentene and the following general formula (1): [In the formula, R １ ~R ４ Each of these independently represents a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a substituent containing a halogen atom, a silicon atom, an oxygen atom, or a nitrogen atom, and R ２and R ３ A rubber composition for tires characterized by containing a copolymer with a norbornene compound represented by [ ], where m is an integer from 0 to 2, and where the compounds may bond to each other to form a ring.

[0008] [2] The tire rubber composition according to [1], wherein the content of the copolymer of cyclopentene and norbornene compound is 20 to 90 parts by mass per 100 parts by mass of the rubber component.

[0009] [3] The tire rubber composition according to [1] or [2], wherein the copolymer of cyclopentene and norbornene compound has a weight-average molecular weight (Mw) of 200,000 to 1,000,000.

[0010] [4] The tire rubber composition according to any one of [1] to [3], wherein the copolymer of cyclopentene and norbornene compound has a content of 20 to 75% by mass of structural units derived from cyclopentene.

[0011] [5] The tire rubber composition according to any one of [1] to [4], wherein the copolymer of cyclopentene and norbornene compound has a content of 10 to 60% by mass of structural units derived from 2-norbornene.

[0012] [6] The tire rubber composition according to any one of [1] to [5], wherein the copolymer of cyclopentene and norbornene compound has a content of dicyclopentadiene-derived structural units of 10 to 60% by mass.

[0013] [7] The tire rubber composition according to any one of [1] to [6], wherein the content of the thermoplastic resin is 1 to 50 parts by mass per 100 parts by mass of the rubber component.

[0014] [8] The tire rubber composition according to any one of [1] to [7], wherein the thermoplastic resin is at least one selected from the group consisting of rosin resins, terpene resins, petroleum resins, phenolic resins, coal resins, xylene resins, aromatic resins, coumarone resins, indene resins, coumarone-indene resins, olefin resins, polyurethane resins, and acrylic resins.

[0015] [9] The thermoplastic resin is C ５ based resin, C ９ based resin, C ５ -C ９ A tire rubber composition according to any one of [1] to [8], wherein at least one is selected from the group consisting of resins and dicyclopentadiene resins.

[0016]

[10] The tire rubber composition according to any one of [1] to [9], wherein the thermoplastic resin comprises at least one selected from the group consisting of rosin resins and terpene resins.

[0017]

[11] A tire characterized by comprising any one of the tire rubber compositions described in [1] to

[10] .

[0018] According to the present invention, it is possible to provide a tire rubber composition that achieves both wear resistance and wet performance while ensuring low fuel consumption. Furthermore, according to the present invention, it is possible to provide a tire that achieves both wear resistance and wet performance while ensuring low fuel consumption.

[0019] The rubber composition for tires and the tires of the present invention will be described in detail below, based on embodiments thereof.

[0020] <Definitions> The compounds described herein may be derived in part or in whole from fossil resources, from biological resources such as plant resources, or from recycled resources such as used tires. They may also be derived from a mixture of two or more of fossil resources, biological resources, or recycled resources.

[0021] In this specification, "sustainable materials" refers to materials derived from biological resources (biomass resources) and materials derived from recycled resources.

[0022] In this specification, the "biological resource (biomass resource)" refers to a carbon-neutral organic resource derived from living organisms, and includes, for example, those stored in the form of starch, cellulose, etc., the bodies of animals that grow by eating plants, products obtained by processing plants and animals, etc., and is a resource excluding fossil resources (such as petroleum, coal, natural gas, etc.). The biological resource may be edible or inedible, but it does not compete with food, and from the perspective of effective utilization of resources, it is preferably inedible.

[0023] In this specification, the "recycled resource" refers to a resource obtained by recycling (recycling) a product that has been used once, or collected without being used, or discarded. For example, recycled resources include resources obtained by recycling used rubber products such as used tires.

[0024] <Rubber composition for tires> The rubber composition for tires of the present embodiment contains a rubber component and a thermoplastic resin. And in the rubber composition for tires of the present embodiment, the rubber component is a copolymer of cyclopentene and a norbornene-based compound represented by the following general formula (1) (also simply referred to as "a copolymer of cyclopentene and a norbornene-based compound" or "copolymer").): [In the formula, R １ ~R ４ each independently represents a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a substituent containing a halogen atom, a silicon atom, an oxygen atom or a nitrogen atom, and R ２ and R ３ may be bonded to each other to form a ring, and m is an integer of 0 to 2.], and is characterized by containing a copolymer of cyclopentene and a norbornene-based compound (also simply referred to as "a copolymer of cyclopentene and a norbornene-based compound" or "copolymer").

[0025] In the tire rubber composition of this embodiment, the copolymer of cyclopentene and norbornene-based compound is characterized by having crosslinking points and by the entanglement of polymer chains. In the tire rubber composition of this embodiment, the entanglement of polymer chains improves wear resistance. Furthermore, in the tire rubber composition of this embodiment, the entanglement of polymer chains in the copolymer of cyclopentene and norbornene-based compound reduces hysteresis loss (tanδ), thereby improving fuel efficiency. In addition, while wear resistance and wet grip (WET) performance are usually mutually exclusive parameters, thermoplastic resins can control the viscoelasticity of rubber to a low level. Therefore, by combining the copolymer of cyclopentene and norbornene-based compound with a thermoplastic resin, it is possible to achieve both wear resistance and WET performance. Accordingly, the tire rubber composition of this embodiment can achieve both wear resistance and WET performance while ensuring fuel efficiency.

[0026] (Rubber component) The tire rubber composition of this embodiment contains a rubber component, which provides the composition with rubber elasticity. The rubber component of the tire rubber composition of this embodiment contains a copolymer of cyclopentene and a norbornene compound represented by the above general formula (1), and may further contain other rubbers.

[0027] - Copolymer of cyclopentene and norbornene-based compound - The copolymer of cyclopentene and norbornene-based compound comprises structural units derived from cyclopentene and structural units derived from the norbornene-based compound represented by the above general formula (1). In one preferred embodiment, the copolymer of cyclopentene and norbornene-based compound is a ring-opened copolymer, and more particularly, a cyclopentene ring-opened copolymer. In another preferred embodiment, the copolymer of cyclopentene and norbornene-based compound is a linear polymer or a branched polymer, and more particularly, a linear polymer.

[0028] In the above general formula (1), R １ ~R ４Each of these independently represents a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a substituent containing a halogen atom, a silicon atom, an oxygen atom, or a nitrogen atom, and R ２ and R ３ These groups may bond to each other to form a ring, and m is an integer from 0 to 2. Examples of hydrocarbon groups having 1 to 20 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, neopentyl, hexyl, and octyl groups; alkenyl groups such as vinyl, allyl, 2-pentenyl, 3-pentenyl, and 4-methyl-3-pentenyl groups; aryl groups such as phenyl, tolyl, 2,6-dimethylphenyl, 2,6-diisopropylphenyl, and naphthyl groups; and aralkyl groups such as benzyl and phenethyl groups.

[0029] Examples of norbornene compounds represented by the above general formula (1) include 2-norbornene, 5-methyl-2-norbornene, 5-ethyl-2-norbornene, 5-butyl-2-norbornene, 5-hexyl-2-norbornene, 5-decyl-2-norbornene, 5-cyclohexyl-2-norbornene, 5-cyclopentyl-2-norbornene, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene, 5-propenyl-2-norbornene, 5-cyclohexenyl-2-norbornene, 5-cyclopentenyl-2-norbornene, 5-phenyl-2-norbornene, and tetracyclo[9.2.1.0 ２，１０ . 0 ３，８ ] Tetradeca-3,5,7,12-tetraene (also called "1,4-methano-1,4,4a,9a-tetrahydro-9H-fluorene"), tetracyclo[10.2.1.0 ２，１１ . 0 ４，９ ] Pentadeca-4,6,8,13-tetraene (also called "1,4-methano-1,4,4a,9,9a,10-hexahydroanthracene"), dicyclopentadiene, methyldicyclopentadiene, dihydrodicyclopentadiene ("tricyclo[5.2.1.0 ２，６Bicyclo[2.2.1]hept-2-enes, which are unsubstituted or have hydrocarbon substituents, such as dec-8-ene; tetracyclo[6.2.1.1] ３，６ . 0 ２，７ ] Dodeca-4-ene, 9-methyltetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Dodeca-4-ene, 9-ethyltetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Dodeca-4-ene, 9-cyclohexyltetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Dodeca-4-ene, 9-cyclopentyltetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Dodeca-4-ene, 9-methylenetetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Dodeca-4-ene, 9-ethylidenetetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Dodeca-4-ene, 9-vinyltetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Dodeca-4-ene, 9-propenyltetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Dodeca-4-ene, 9-cyclohexenyltetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Dodeca-4-ene, 9-cyclopentenyltetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Dodeca-4-ene, 9-phenyltetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Tetracyclo[6.2.1.1] unsubstituted or hydrocarbon substituents such as dodeca-4ene ３，６ . 0 ２，７ ] Dodeca-4-enes; Bicyclo[2.2.1]hept-2-enes having an alkoxycarbonyl group, such as methyl 5-norbornene-2-carboxylate, ethyl 5-norbornene-2-carboxylate, methyl 2-methyl-5-norbornene-2-carboxylate, and ethyl 2-methyl-5-norbornene-2-carboxylate; Tetracyclo[6.2.1.1 ３，６ . 0２，７ ] Dodeca-9-ene-4-carboxylate methyl, 4-methyltetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Tetracyclo[6.2.1.1] containing an alkoxycarbonyl group such as methyl dodeca-9-ene-4-carboxylate ３，６ . 0 ２，７ ] Dodeca-4-enes; Bicyclo[2.2.1]hept-2-enes having a hydroxycarbonyl group or acid anhydride group, such as 5-norbornene-2-carboxylic acid, 5-norbornene-2,3-dicarboxylic acid, and 5-norbornene-2,3-dicarboxylic acid anhydride; Tetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Dodeca-9-ene-4-carboxylic acid, tetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Dodeca-9-ene-4,5-dicarboxylic acid, tetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Tetracyclo[6.2.1.1] having a hydroxycarbonyl group or acid anhydride group such as dodeca-9-ene-4,5-dicarboxylic acid anhydride ３，６ . 0 ２，７ ] Dodeca-4-enes; Bicyclo[2.2.1]hepto-2-enes having a hydroxyl group, such as 5-hydroxy-2-norbornene, 5-hydroxymethyl-2-norbornene, 5,6-di(hydroxymethyl)-2-norbornene, 5,5-di(hydroxymethyl)-2-norbornene, 5-(2-hydroxyethoxycarbonyl)-2-norbornene, 5-methyl-5-(2-hydroxyethoxycarbonyl)-2-norbornene; Tetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Dodeca-9-ene-4-methanol, tetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Tetracyclo[6.2.1.1] such as dodeca-9-en-4-ol having a hydroxyl group ３，６ . 0 ２，７ ] Dodeca-4-enes; Bicyclo[2.2.1]hept-2-enes having a hydrocarbonyl group such as 5-norbornene-2-carbaldehyde; Tetracyclo[6.2.1.1 ３，６. 0 ２，７ ] Tetracyclo[6.2.1.1] such as dodeca-9-ene-4-carbaldehyde having a hydrocarbonyl group ３，６ . 0 ２，７ ] Dodeca-4-enes; Bicyclo[2.2.1]hept-2-enes having an alkoxycarbonyl group and a hydroxycarbonyl group, such as 3-methoxycarbonyl-5-norbornene-2-carboxylic acid; Bicyclo[2.2.1]hept-2-enes having a carbonyloxy group, such as 5-norbornene-2-yl acetate, 2-methyl-5-norbornene-2-yl acetate, 5-norbornene-2-yl acrylate, 5-norbornene-2-yl methacrylate; 9-tetracyclo[6.2.1.1] acetate ３，６ . 0 ２，７ ] Dodeca-4-enyl, 9-tetracycloacrylate [6.2.1.1 ３，６ . 0 ２，７ ] Dodeca-4-enyl, 9-tetracyclomethacrylate [6.2.1.1 ３，６ . 0 ２，７ ] Tetracyclo[6.2.1.1] having a carbonyloxy group such as dodeca-4-enyl ３，６ . 0 ２，７ ] Dodeca-4-enes; Bicyclo[2.2.1]hept-2-enes having a nitrogen atom-containing functional group such as 5-norbornene-2-carbonitrile, 5-norbornene-2-carboxamide, 5-norbornene-2,3-dicarboxylic acidimide; Tetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Dodeca-9-ene-4-carbonitrile, tetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Dodeca-9-ene-4-carboxamide, tetracyclo[6.2.1.1 ３，６ . 0 ２，７ ] Tetracyclo[6.2.1.1] having a functional group containing a nitrogen atom, such as dodeca-9-ene-4,5-dicarboxylic acidimide ３，６ . 0 ２，７ ] Dodeca-4-enes; Bicyclo[2.2.1]hept-2-enes having halogen atoms such as 5-chloro-2-norbornene; 9-chlorotetracyclo[6.2.1.1 ３，６ . 0 ２，７tetracyclo[6.2.1.1]dodec-4-ene and the like having a halogen atom ３，６ .0 ２，７ dodec-4-enes; bicyclo[2.2.1]hept-2-enes having a functional group containing a silicon atom such as 5-trimethoxysilyl-2-norbornene, 5-triethoxysilyl-2-norbornene; 4-trimethoxysilyltetracyclo[6.2.1.1 ３，６ .0 ２，７ dodec-9-ene, 4-triethoxysilyltetracyclo[6.2.1.1 ３，６ .0 ２，７ dodec-9-ene and the like having a functional group containing a silicon atom such as tetracyclo[6.2.1.1 ３，６ .0 ２，７ dodec-4-enes; and the like. The norbornene-based compound may be used alone or in combination of two or more kinds.

[0030] As the norbornene-based compound represented by the above general formula (1), in the above general formula (1), those in which m is 0 or 1 are preferable, and those in which m is 0 are more preferable. Further, in the above general formula (1), R １ ~R ４ may be the same or different.

[0031] Among the norbornene-based compounds represented by the above general formula (1), from the viewpoints of low fuel consumption and abrasion resistance of the rubber composition, R １ ~R ４ in the above general formula (1) are preferably a hydrogen atom, a linear hydrocarbon group having 1 to 20 carbon atoms, or a substituent containing a halogen atom, a silicon atom, an oxygen atom or a nitrogen atom. In this case, R １ ~R ４ do not bond to each other and may be a group that does not form a ring, and is not particularly limited, and may be the same or different. R １ ~R ４ are preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Also in this case, those in which m is 0 or 1 are preferable, and those in which m is {0} are more preferable. R １ ~R ４However, as norbornene compounds which are substituents containing a hydrogen atom, a chain hydrocarbon group having 1 to 20 carbon atoms, or a halogen atom, a silicon atom, an oxygen atom, or a nitrogen atom, bicyclo[2.2.1]hept-2-ene compounds that are unsubstituted or have hydrocarbon substituents are preferred, and among these, 2-norbornene is particularly preferred.

[0032] Furthermore, as a norbornene compound represented by the above general formula (1), R ２ and R ３ Compounds in which R and R are bonded to each other to form a ring are also preferred. Here, R ２ and R ３ Specific examples of ring structures formed by the bonding of these rings include cyclopentane rings, cyclopentene rings, cyclohexane rings, cyclohexene rings, and benzene rings, which may form polycyclic structures and may also have substituents. Among these, cyclopentane rings, cyclopentene rings, and benzene rings are preferred, and compounds having a cyclopentene ring alone, or compounds having a polycyclic structure of a cyclopentane ring and a benzene ring are particularly preferred. ２ , R ３ Other than R １ , R ４ R may be the same or different, and is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. In this case, it is also preferable that m is 0. ２ and R ３ As norbornene compounds in which these are bonded to each other to form a ring, bicyclo[2.2.1]hept-2-enes are preferred, either unsubstituted or having hydrocarbon substituents, and among these, dicyclopentadiene is particularly preferred.

[0033] The copolymer of cyclopentene and norbornene compound preferably contains 20 to 75% by mass of cyclopentene-derived structural units, more preferably 25 to 70% by mass, even more preferably 30 to 65% by mass, and particularly preferably 35 to 60% by mass, relative to the total repeating structural units of the copolymer. By setting the content of cyclopentene-derived structural units in the copolymer to a range of 20 to 75% by mass, the fuel efficiency and wear resistance of the rubber composition containing the copolymer can be further improved, and by applying the rubber composition to a tire, the fuel efficiency and wear resistance of the tire can be further improved.

[0034] The copolymer of cyclopentene and norbornene compound has a content of structural units derived from the norbornene compound represented by the general formula (1) that is preferably 10 to 80% by mass, more preferably 20 to 70% by mass, even more preferably 25 to 65% by mass, and particularly preferably 40 to 65% by mass, relative to the total repeating structural units of the copolymer. By setting the content of structural units derived from the norbornene compound represented by the general formula (1) in the copolymer to a range of 10 to 80% by mass, the fuel efficiency and wear resistance of the rubber composition containing the copolymer can be further improved, and by applying the rubber composition to a tire, the fuel efficiency and wear resistance of the tire can be further improved.

[0035] In the copolymer of cyclopentene and norbornene-based compound, the norbornene-based compound represented by the general formula (1) is preferably 2-norbornene and / or dicyclopentadiene. Since 2-norbornene and dicyclopentadiene are readily available, copolymers of cyclopentene and 2-norbornene and / or dicyclopentadiene are readily available. Therefore, tire rubber compositions containing copolymers of cyclopentene and 2-norbornene and / or dicyclopentadiene are advantageous in terms of cost.

[0036] When 2-norbornene is used as the norbornene-based compound represented by the above general formula (1), the copolymer of cyclopentene and the norbornene-based compound preferably contains 10 to 60% by mass of structural units derived from 2-norbornene, and more preferably 20 to 60% by mass, relative to the total repeating structural units of the copolymer. By setting the content of structural units derived from 2-norbornene in the copolymer to a range of 10 to 60% by mass, the fuel efficiency and wear resistance of the rubber composition containing the copolymer can be further improved, and by applying the rubber composition to a tire, the fuel efficiency and wear resistance of the tire can be further improved.

[0037] When dicyclopentadiene is used as the norbornene-based compound represented by the above general formula (1), the copolymer of cyclopentene and the norbornene-based compound preferably has a content of dicyclopentadiene-derived structural units of 10 to 60% by mass, and more preferably 20 to 50% by mass, relative to the total repeating structural units of the copolymer. By setting the content of dicyclopentadiene-derived structural units in the copolymer to a range of 10 to 60% by mass, the fuel efficiency and wear resistance of the rubber composition containing the copolymer can be further improved, and by applying the rubber composition to a tire, the fuel efficiency and wear resistance of the tire can be further improved.

[0038] In one preferred embodiment, the copolymer of cyclopentene and norbornene-based compound may be a terpolymer of cyclopentene (CP), 2-norbornene (NB), and dicyclopentadiene (DCPD). Since the terpolymer of cyclopentene, 2-norbornene, and dicyclopentadiene has a significant effect in improving fuel efficiency, the rubber composition containing this terpolymer exhibits further improved fuel efficiency.

[0039] The copolymer of cyclopentene and norbornene compound may be copolymerized with other monomers that can copolymerize with cyclopentene and the norbornene compound represented by the general formula (1) above. Examples of such other monomers include cyclic monoolefins such as cyclopropene, cyclobutene, methylcyclopentene, cyclohexene, methylcyclohexene, cycloheptene, and cyclooctene; cyclic diolefins such as cyclohexadiene, methylcyclohexadiene, cyclooctadiene, and methylcyclooctadiene; and polycyclic cycloolefins having aromatic rings such as phenylcyclooctene, 5-phenyl-1,5-cyclooctadiene, and phenylcyclopentene. The content of structural units derived from other monomers in the copolymer of cyclopentene and norbornene compound is preferably 40% by mass or less, more preferably 30% by mass or less, relative to the total repeating structural units of the copolymer, and it is particularly preferable that structural units derived from other monomers are substantially absent.

[0040] The copolymer of cyclopentene and norbornene compound preferably has a weight-average molecular weight (Mw) of 200,000 to 1,000,000, more preferably 200,000 to 800,000, even more preferably 200,000 to 700,000, and particularly preferably 200,000 to 600,000. Copolymers with a weight-average molecular weight (Mw) in the range of 200,000 to 1,000,000 are easy to manufacture and have good processability (workability). Furthermore, by setting the weight-average molecular weight (Mw) of the copolymer to the range of 200,000 to 1,000,000, the fuel efficiency and wear resistance of the rubber composition containing the copolymer can be further improved, and by applying the rubber composition to a tire, the fuel efficiency and wear resistance of the tire can be further improved. Furthermore, the copolymer of cyclopentene and norbornene compound preferably has a ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn) (Mw / Mn, also called "molecular weight distribution") of 1.0 to 5.0, more preferably 1.5 to 2.9, even more preferably 1.5 to 2.5, and particularly preferably 1.5 to 2.3. Here, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the copolymer are polystyrene-converted values ​​measured by gel permeation chromatography (GPC).

[0041] The copolymer of cyclopentene and norbornene-based compound preferably has a cis / trans ratio of 0 / 100 to 60 / 40, more preferably 5 / 95 to 55 / 45, even more preferably 10 / 90 to 50 / 50, and particularly preferably 15 / 85 to 39 / 61. The cis / trans ratio is the ratio of cis to trans structures of double bonds present in the repeating units constituting the copolymer of cyclopentene and norbornene-based compound. By setting the cis / trans ratio of the copolymer within the above range, the fuel efficiency and wear resistance of the rubber composition containing the copolymer can be further improved, and by applying the rubber composition to a tire, the fuel efficiency and wear resistance of the tire can be further improved.

[0042] The copolymer of cyclopentene and norbornene compound has a glass transition temperature (Tg) preferably -80°C to 10°C, more preferably -75°C to 0°C, and even more preferably -70°C to -10°C. By setting the glass transition temperature (Tg) of the copolymer within the above range, the fuel efficiency and wear resistance of the rubber composition containing the copolymer can be further improved, and by applying the rubber composition to a tire, the fuel efficiency and wear resistance of the tire can be further improved. The glass transition temperature of the copolymer can be controlled, for example, by adjusting the type and amount of norbornene compound used. Here, the glass transition temperature (Tg) of the copolymer is a value measured using a differential scanning calorimeter (DSC) with a temperature increase of 10°C / min.

[0043] The copolymer of cyclopentene and norbornene compound may have a modifying group at the end of the polymer chain. Having such a terminal modifying group can further increase the affinity to the filler, improve the dispersibility of the filler in the rubber composition, and as a result, further improve the fuel efficiency and wear resistance of the rubber composition. The modifying group to be introduced at the end of the polymer chain of the copolymer is not particularly limited, but a modifying group containing an atom selected from the group consisting of atoms of Group 15 of the periodic table, atoms of Group 16 of the periodic table, and silicon atoms is preferred. As a modifying group for forming the terminal modifying group, a modifying group containing an atom selected from the group consisting of nitrogen atoms, oxygen atoms, phosphorus atoms, sulfur atoms, and silicon atoms is more preferred from the viewpoint of increasing the affinity to the filler, and among these, a modifying group containing an atom selected from the group consisting of nitrogen atoms, oxygen atoms, and silicon atoms is even more preferred.

[0044] Modified groups containing a nitrogen atom include amino groups, pyridyl groups, imino groups, amide groups, nitro groups, urethane bonding groups, or hydrocarbon groups containing any of these groups. Modified groups containing an oxygen atom include hydroxyl groups, carboxylic acid groups, ether groups, ester groups, carbonyl groups, aldehyde groups, epoxy groups, or hydrocarbon groups containing any of these groups. Modified groups containing a silicon atom include alkylsilyl groups, oxysilyl groups, or hydrocarbon groups containing any of these groups. Modified groups containing a phosphorus atom include phosphoric acid groups, phosphino groups, or hydrocarbon groups containing any of these groups. Modified groups containing a sulfur atom include sulfonyl groups, thiol groups, thioether groups, or hydrocarbon groups containing any of these groups. Furthermore, the modified group may contain multiple of the above-mentioned groups. Among these, from the viewpoint of further improving the fuel efficiency and wear resistance of the rubber composition, amino groups, pyridyl groups, imino groups, amide groups, hydroxyl groups, carboxylic acid groups, aldehyde groups, epoxy groups, oxysilyl groups, or hydrocarbon groups containing any of these groups are preferred, and from the viewpoint of affinity to fillers (especially silica, etc.), oxysilyl groups are particularly preferred. Here, an oxysilyl group refers to a group having a silicon-oxygen bond.

[0045] Examples of the oxysilyl group include alkoxysilyl groups, aryloxysilyl groups, acyloxy groups, alkylsiloxysilyl groups, and arylsiloxysilyl groups. Furthermore, hydroxysilyl groups obtained by hydrolyzing alkoxysilyl groups, aryloxysilyl groups, or acyloxy groups can also be mentioned. Among these, alkoxysilyl groups are preferred from the viewpoint of affinity for silica. The alkoxysilyl group is a group formed by one or more alkoxy groups bonded to a silicon atom. Specific examples include trimethoxysilyl groups, dimethoxymethylsilyl groups, methoxydimethylsilyl groups, methoxydichlorosilyl groups, triethoxysilyl groups, diethoxymethylsilyl groups, ethoxydimethylsilyl groups, dimethoxyethoxysilyl groups, methoxydiethoxysilyl groups, and tripropoxysilyl groups.

[0046] The proportion of modified groups introduced at the polymer chain ends of the copolymer of cyclopentene and norbornene-based compound is not particularly limited, but it is preferably 10% or more, more preferably 20% or more, even more preferably 30% or more, and particularly preferably 40% or more, as a percentage of the number of copolymer chain ends with modified groups / total number of copolymer chain ends. A higher proportion of terminal modified groups is preferable because it increases the affinity to the filler. The method for measuring the proportion of modified groups introduced at the polymer chain ends is not particularly limited, but an example is when an oxysilyl group is introduced as the terminal modified group. １ It can be determined from the peak area ratio corresponding to the oxysilyl group, which is obtained by 1H-NMR spectroscopy, and the number-average molecular weight (Mn) obtained from gel permeation chromatography (GPC).

[0047] The copolymer of cyclopentene and norbornene-based compound has a Mooney viscosity (ML). １＋４ The Mooney viscosity (ML) of the copolymer is preferably 20 to 150, more preferably 22 to 120, and particularly preferably 25 to 90. １＋４ The values ​​(100°C) were measured according to JIS K6300.

[0048] The method for producing the copolymer of cyclopentene and norbornene-based compound is not particularly limited, but one example is a method of copolymerizing cyclopentene and a norbornene-based compound represented by the above general formula (1) in the presence of a ring-opening polymerization catalyst.

[0049] The ring-opening polymerization catalyst is not particularly limited as long as it can perform ring-opening copolymerization between cyclopentene and a norbornene-based compound represented by the general formula (1) above, but ruthenium carbene complexes and Group 6 transition metal compounds of the periodic table containing halogen atoms (hereinafter also referred to as "Group 6 transition metal compounds of the periodic table") are preferred. These ring-opening polymerization catalysts may be used individually or in combination of two or more.

[0050] The ruthenium carbene complexes include bis(tricyclohexylphosphine)benzylidene ruthenium dichloride, bis(triphenylphosphine)-3,3-diphenylpropenylidene ruthenium dichloride, bis(tricyclohexylphosphine)t-butylvinylidene ruthenium dichloride, dichloro-(3-phenyl-1H-indene-1-ylidene)bis(tricyclohexylphosphine)ruthenium, bis(1,3-diisopropylimidazoline-2-ylidene)benzylidene ruthenium dichloride, and bis(1,3-dicyclohexylimidazoline-2-ylidene). Examples include (dazoline-2-ylidene)benzylidene ruthenium dichloride, (1,3-dimethylimidazoline-2-ylidene)(tricyclohexylphosphine)benzylidene ruthenium dichloride, (1,3-dimethylimidazolidin-2-ylidene)(tricyclohexylphosphine)benzylidene ruthenium dichloride, bis(tricyclohexylphosphine)ethoxymethylidene ruthenium dichloride, and (1,3-dimethylimidazolidin-2-ylidene)(tricyclohexylphosphine)ethoxymethylidene ruthenium dichloride.

[0051] The aforementioned Group 6 transition metal compounds are compounds having a Group 6 transition metal atom of the periodic table (long-period periodic table, the same applies hereinafter), specifically, compounds having a chromium atom, a molybdenum atom, or a tungsten atom. Compounds having a molybdenum atom or a tungsten atom are preferred, and compounds having a tungsten atom are more preferred from the viewpoint of high solubility in cyclopentene. Specific examples of the aforementioned Group 6 transition metal compounds include molybdenum compounds such as molybdenum pentachloride, molybdenum oxotetrachloride, and molybdenum (phenylimide) tetrachloride; tungsten compounds such as tungsten hexachloride, tungsten oxotetrachloride, tungsten (phenylimide) tetrachloride, monocatecollate tungsten tetrachloride, bis(3,5-diter-butyl)catecollate tungsten dichloride, and bis(2-chloroetherate) tetrachloride; and the like.

[0052] The amount of the ring-opening polymerization catalyst used is typically in the range of 1:500 to 1:2,000,000, preferably 1:700 to 1:1,500,000, and more preferably 1:1,000 to 1:1,000,000, in molar ratio of (ring-opening polymerization catalyst: monomer used for copolymerization). When using a Group 6 transition metal compound, the amount of the Group 6 transition metal compound used is preferably in the range of 1:100 to 1:200,000, more preferably 1:200 to 1:150,000, and even more preferably 1:500 to 1:100,000, in molar ratio of "Group 6 transition metal atom in the ring-opening polymerization catalyst: monomer used for ring-opening polymerization".

[0053] When using the Group 6 transition metal compound of the periodic table as the ring-opening polymerization catalyst, it is preferable to use it in combination with the organoaluminum compound represented by the following general formula (2). The organoaluminum compound acts as a ring-opening polymerization catalyst together with the Group 6 transition metal compound of the periodic table described above. (R ５ ) ３－ｘ Al(OR) ６ ) ｘ ... (2) In the above general formula (2), R ５ and R ６ Each of these is an independent hydrocarbon group having 1 to 20 carbon atoms, preferably a hydrocarbon group having 1 to 10 carbon atoms. Also, x is 0 < x < 3.

[0054] In the above general formula (2), R ５ and R ６ Examples include alkyl groups such as methyl, ethyl, isopropyl, n-propyl, isobutyl, n-butyl, t-butyl, n-hexyl, cyclohexyl, n-octyl, and n-decyl groups; and aryl groups such as phenyl, 4-methylphenyl, 2,6-dimethylphenyl, 2,6-diisopropylphenyl, and naphthyl groups.

[0055] Furthermore, in the general formula (2) above, x is 0 < x < 3. That is, in the general formula (2), R ５ and OR ６The composition ratios of these elements can take any value within the ranges of 0 < 3 - x < 3 and 0 < x < 3, respectively, but from the viewpoint of achieving high polymerization activity, it is preferable that x is 0.5 < x < 1.5.

[0056] The organoaluminum compound represented by the above general formula (2) can be synthesized, for example, by the reaction of trialkylaluminum with an alcohol, as shown in the following general formula (3). (R ５ ) ３ Al + xR ６ OH → (R ５ ) ３－ｘ Al(OR) ６ ) ｘ + (R ６ ) ｘ H... (3)

[0057] Furthermore, x in the above general formula (2) can be arbitrarily controlled by defining the reaction ratio of the corresponding trialkylaluminum and alcohol, as shown in the above general formula (3).

[0058] The amount of the organoaluminum compound used varies depending on the type of organoaluminum compound used, but is preferably 0.1 to 100 moles, more preferably 0.2 to 50 moles, and even more preferably 0.5 to 20 moles, relative to the Group 6 transition metal atoms constituting the Group 6 transition metal compound. If the amount of organoaluminum compound used is too small, the polymerization activity may be insufficient, and if it is too large, side reactions tend to occur more easily during ring-opening polymerization.

[0059] The polymerization reaction may be carried out in solvent-free conditions or in solution. When copolymerizing in solution, the solvent used is not particularly limited as long as it is inert in the polymerization reaction and capable of dissolving cyclopentene, norbornene compounds represented by the general formula (1) above, polymerization catalysts, etc. used in copolymerization, but it is preferable to use a hydrocarbon solvent or a halogen solvent. Examples of hydrocarbon solvents include aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; aliphatic hydrocarbons such as hexane, n-heptane, and n-octane; and alicyclic hydrocarbons such as cyclohexane, cyclopentane, and methylcyclohexane. Examples of halogen solvents include haloalkanes such as dichloromethane and chloroform; and aromatic halogens such as chlorobenzene and dichlorobenzene. These solvents may be used individually or in mixtures of two or more.

[0060] When copolymerizing cyclopentene with a norbornene-based compound represented by the general formula (1) above, an olefin compound or diolefin compound may be added to the polymerization reaction system as a molecular weight adjuster to adjust the molecular weight of the resulting copolymer, if necessary. The olefin compound is not particularly limited as long as it is an organic compound having an ethylenically unsaturated bond, and examples include α-olefins such as 1-butene, 1-pentene, 1-hexene, and 1-octene; styrenes such as styrene and vinyltoluene; halogen-containing vinyl compounds such as allyl chloride; alkenyl alcohols such as allyl alcohol and 5-hexenol; silicon-containing vinyl compounds such as allyltrimethoxysilane, allyltriethoxysilane, allyltrichlorosilane, and styryltrimethoxysilane; and disubstituted olefins such as 2-butene and 3-hexene. Furthermore, examples of the diolefin compounds include non-conjugated diolefins such as 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,6-heptadiene, 2-methyl-1,4-pentadiene, and 2,5-dimethyl-1,5-hexadiene. The amount of olefin compounds and diolefin compounds used as molecular weight adjusters can be appropriately selected according to the molecular weight of the copolymer to be produced, but the molar ratio with respect to the monomer used in copolymerization is usually in the range of 1 / 100 to 1 / 100,000, preferably 1 / 200 to 1 / 50,000, and more preferably 1 / 500 to 1 / 10,000.

[0061] Furthermore, when the copolymer of cyclopentene and norbornene-based compounds has a modifying group at the polymer chain end, it is preferable to use a modifying group-containing olefinic unsaturated hydrocarbon compound as a molecular weight adjuster instead of the olefin or diolefin compounds mentioned above. By using a modifying group-containing olefinic unsaturated hydrocarbon compound, the modifying group can be suitably introduced at the polymer chain end of the copolymer obtained by copolymerization. The modifying group-containing olefinic unsaturated hydrocarbon compound is not particularly limited and can be any compound that has a modifying group and one olefinic carbon-carbon double bond that is metathesis reactive. For example, if it is desired to introduce an oxysilyl group at the polymer chain end of the copolymer, an oxysilyl group-containing olefinic unsaturated hydrocarbon can be present in the polymerization reaction system.

[0062] Examples of the oxysilyl group-containing olefinic unsaturated hydrocarbons include alkoxysilane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allylmethoxydimethylsilane, allyltriethoxysilane, allylethoxydimethylsilane, styryltrimethoxysilane, styryltriethoxysilane, styrylethyltriethoxysilane, allyltriethoxysilylmethyl ether, and allyltriethoxysilylmethylethylamine, which introduce a modifying group to only one end (one end) of the polymer chain of the copolymer; vinyltriphenoxysilane, allyltriphenoxysilane, and ali. Examples include aryloxysilane compounds such as ruphenoxydimethylsilane; asiloxilane compounds such as vinyltriacetoxysilane, allyltriacetoxysilane, allyldiacetoxymethylsilane, and allylacetoxydimethylsilane; alkylsiloxysilane compounds such as allyltris(trimethylsiloxy)silane; arylsiloxysilane compounds such as allyltris(triphenylsiloxy)silane; and polysiloxane compounds such as 1-allylheptamethyltrisiloxane, 1-allylnonamethyltetrasiloxane, 1-allylnonamethylcyclopentasiloxane, and 1-allylundecamethylcyclohexasiloxane. Furthermore, to introduce modifying groups to both ends (both terminals) of the polymer chain of the copolymer, alkoxysilane compounds such as bis(trimethoxysilyl)ethylene, bis(triethoxysilyl)ethylene, 2-butene-1,4-di(trimethoxysilane), 2-butene-1,4-di(triethoxysilane), and 1,4-di(trimethoxysilylmethoxy)-2-butene; aryloxysilane compounds such as 2-butene-1,4-di(triphenoxysilane); and 2-butene Examples include asyloxysilane compounds such as -1,4-di(triacetoxysilane); alkylsiloxysilane compounds such as 2-butene-1,4-di[tris(trimethylsiloxy)silane]; arylsiloxysilane compounds such as 2-butene-1,4-di[tris(triphenylsiloxy)silane]; and polysiloxane compounds such as 2-butene-1,4-di(heptamethyltrisiloxane) and 2-butene-1,4-di(undecamethylcyclohexasiloxane).

[0063] The aforementioned olefinic unsaturated hydrocarbon compound containing the modifying group acts not only to introduce the modifying group to the polymer chain ends of the copolymer, but also as a molecular weight adjuster. Therefore, the amount of the olefinic unsaturated hydrocarbon compound containing the modifying group used can be appropriately selected according to the molecular weight of the copolymer to be produced, but is typically in the range of 1 / 100 to 1 / 100,000, preferably 1 / 200 to 1 / 50,000, and more preferably 1 / 500 to 1 / 10,000, in molar ratio relative to the monomer used in copolymerization.

[0064] The polymerization reaction temperature is not particularly limited, but is preferably -100°C or higher, more preferably -50°C or higher, even more preferably 0°C or higher, and especially preferably 20°C or higher. The upper limit of the polymerization reaction temperature is not particularly limited, but is preferably less than 120°C, more preferably less than 100°C, even more preferably less than 90°C, and especially preferably less than 80°C. The polymerization reaction time is not particularly limited, but is preferably 1 minute to 72 hours, more preferably 10 minutes to 20 hours.

[0065] The copolymer obtained by the polymerization reaction may optionally contain antioxidants such as phenolic stabilizers, phosphorus-based stabilizers, or sulfur-based stabilizers. The amount of antioxidant added should be determined appropriately depending on its type and other factors. Furthermore, the copolymer may optionally contain a spreading oil. When the copolymer is obtained as a polymerization solution, known recovery methods can be used to recover the copolymer from the polymerization solution. For example, a method can be employed in which the solvent is separated by steam stripping, the solid is filtered off, and then the solid is dried to obtain a solid copolymer.

[0066] The content of the copolymer of cyclopentene and norbornene compound is preferably 20 to 90 parts by mass, and more preferably 30 to 85 parts by mass, per 100 parts by mass of the rubber component. When the content of the copolymer of cyclopentene and norbornene compound is in the range of 20 to 90 parts by mass per 100 parts by mass of the rubber component, the balance between the low fuel consumption and wear resistance of the rubber composition is further improved, and by applying this rubber composition to a tire, the balance between the low fuel consumption and wear resistance of the tire can be improved.

[0067] -Diene-based rubber- The rubber component may further contain other diene-based rubbers. By including the copolymer of cyclopentene and norbornene-based compound and a diene-based rubber different from the copolymer in the rubber component, wear resistance can be further improved while ensuring low fuel consumption. Examples of the diene-based rubber include natural rubber (NR), synthetic isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), and chloroprene rubber (CR). Among these, styrene-butadiene rubber (SBR) is preferred. The content of these other diene-based rubbers is preferably 80 parts by mass or less, more preferably 70 parts by mass or less, even more preferably 50 parts by mass or less, and preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, per 100 parts by mass of the rubber component.

[0068] -Other Rubbers- The rubber component may further contain other rubbers. Examples of such other rubbers include fluororubber, silicone rubber, and urethane rubber. The content of these other rubbers is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, per 100 parts by mass of the rubber component.

[0069] (Thermoplastic Resin) The tire rubber composition of this embodiment includes a thermoplastic resin. Since the thermoplastic resin can control the viscoelasticity of the rubber to a low level, the inclusion of the thermoplastic resin improves the wet grip (WET) performance of the tire.

[0070] Preferred thermoplastic resins include rosin resins, terpene resins, petroleum resins, phenolic resins, coal resins, xylene resins, aromatic resins, coumarone resins, indene resins, coumarone-indene resins, olefin resins, polyurethane resins, and acrylic resins. These thermoplastic resins may be used individually or in combination of two or more. A tire rubber composition containing at least one thermoplastic resin selected from the group consisting of rosin resins, terpene resins, petroleum resins, phenolic resins, coal resins, xylene resins, aromatic resins, coumarone resins, indene resins, coumarone-indene resins, olefin resins, polyurethane resins, and acrylic resins allows for low control of the rubber's viscoelasticity and further improves wet performance.

[0071] The thermoplastic resin may be hydrogenated, that is, it may be a hydrogenated resin. Furthermore, the thermoplastic resin may have functional groups that interact with fillers such as carbon black and silica introduced into it through modification. Examples of such functional groups 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.

[0072] From the viewpoint of reducing environmental impact, rosin-based resins and terpene-based resins are preferred as the thermoplastic resins. Since rosin-based resins and terpene-based resins are sustainable resins derived from biological resources (biomass resources), incorporating rosin-based resins and / or terpene-based resins into a rubber composition can reduce environmental impact. Therefore, a tire rubber composition containing at least one selected from the group consisting of rosin-based resins and terpene-based resins as the thermoplastic resin can increase the use rate of sustainable materials in tires when applied to tires.

[0073] Examples of rosin-based resins include natural resin rosins such as gum rosin contained in raw pine resin and tall oil, tall oil rosin, and wood rosin. Examples of modified rosins, rosin derivatives, and modified rosin derivatives include polymerized rosin and its partially hydrogenated rosin; glycerol ester rosin and its partially hydrogenated or fully hydrogenated rosin; pentaerythritol ester rosin and its partially hydrogenated or polymerized rosin; and so on.

[0074] The aforementioned terpene resins are solid resins obtained by polymerizing turpentine oil, which is obtained simultaneously when rosin is obtained from pine trees, or polymer components separated therefrom, using a Friedel-Crafts type catalyst. Examples include β-pinene resin and α-pinene resin. Terpene resins also include terpene-aromatic compound resins, and typical examples of such terpene-aromatic compound resins include terpene-phenol resin and styrene-terpene resin. Terpene-phenol resins can be obtained by reacting terpenes with various phenols using a Friedel-Crafts type catalyst, or by further condensation with formalin. Styrene-terpene resins can be obtained by reacting styrene with terpenes using a Friedel-Crafts type catalyst. There are no particular restrictions on the terpenes used as raw materials, but monoterpene hydrocarbons such as α-pinene and limonene are preferred, those containing α-pinene are more preferred, and α-pinene is particularly preferred.

[0075] The aforementioned petroleum-based resin is C ５ based resin, C ９ based resin, C ５ -C ９ A resin system, or a dicyclopentadiene (DCPD) resin system, is preferred. ５ based resin, C ９ based resin, C ５ -C ９ The C-type resin, dicyclopentadiene-based (DCPD) resin, can improve wear resistance and fuel efficiency in a balanced manner. Therefore, as the thermoplastic resin, ５ based resin, C ９ based resin, C ５ -C ９A tire rubber composition comprising at least one selected from the group consisting of resins and dicyclopentadiene (DCPD) resins exhibits a good balance of improved wear resistance and fuel efficiency.

[0076] Said C ５ C resins are C ５ This refers to synthetic petroleum resins, and C ５ As for resins, C obtained by the thermal decomposition of naphtha in the petrochemical industry. ５ Examples include aliphatic petroleum resins obtained by (co)polymerizing the fractions. ５ The fraction typically includes olefinic hydrocarbons such as 1-pentene, 2-pentene, 2-methyl-1-butene, 2-methyl-2-butene, and 3-methyl-1-butene, as well as diolefinic hydrocarbons such as 2-methyl-1,3-butadiene, 1,2-pentadiene, 1,3-pentadiene, and 3-methyl-1,2-butadiene.

[0077] Said C ９ C resins are C ９ This refers to synthetic petroleum resins, such as AlCl ３ Ya BF ３ Using Friedelcrafts type catalysts such as C ９ This refers to a solid polymer obtained by polymerizing a fraction. ９ Examples of resin compounds include copolymers mainly composed of indene, α-methylstyrene, vinyltoluene, etc.

[0078] Said C ５ -C ９ C resins are C ５ -C ９ This refers to synthetic petroleum resins, C ５ -C ９ Examples of resins include petroleum-derived C ５ -C １１ The fraction is AlCl ３ BF ３ Examples include solid polymers obtained by polymerization using Friedel-Crafts catalysts such as [list of catalysts], and more specifically, copolymers mainly composed of styrene, vinyltoluene, α-methylstyrene, indene, etc. ５ -C ９ As for resin systems, C ９Resins containing fewer of the above components are preferred from the viewpoint of compatibility with rubber components. Here, "C ９ "The above components are low" means that the total amount of C in the resin is low. ９ This means that the above components are present in an amount of less than 50% by mass, preferably 40% by mass or less.

[0079] The aforementioned dicyclopentadiene (DCPD) resin is a petroleum resin manufactured using dicyclopentadiene (DCPD), obtained by dimerizing cyclopentadiene, as the main raw material. The dicyclopentadiene resin is, for example, AlCl ３ Ya BF ３ It is obtained by polymerizing dicyclopentadiene using Friedel-Crafts type catalysts such as the above.

[0080] The phenolic resin can be obtained, for example, by the reaction of phenols and aldehydes. Examples of phenols used as raw materials include phenol and cresol, and examples of aldehydes include formaldehyde. The phenolic resin may be a resol-type phenolic resin or a novolac-type phenolic resin. The phenolic resin may also be oil-modified, and examples of such oils include rosin oil, tall oil, cashew oil, oleic acid, linoleic acid, and linolenic acid. Examples of the phenolic resin include alkylphenol formaldehyde resins and their rosin-modified derivatives, alkylphenol acetylene resins, modified alkylphenol resins, and terpene phenol resins.

[0081] The aforementioned coal-based resin refers to a solid polymer obtained by polymerizing fractions derived from coal (particularly coal cracking oil). Compounds contained in the coal cracking oil fraction include styrene, vinyltoluene, coumarone, and indene.

[0082] The aforementioned xylene-based resin refers to a resin that contains units derived from xylene as monomer units. Examples of such xylene-based resins include xyleneformaldehyde resin.

[0083] The aforementioned aromatic resin refers to a resin that contains units derived from aromatic monomers as monomer units. Examples of such aromatic resins include homopolymers of aromatic monomers, copolymers of two or more aromatic monomers, and copolymers of aromatic monomers with other monomers. Examples of aromatic monomers include styrene monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, and p-phenylstyrene; phenol monomers such as phenol, alkylphenol, and alkoxyphenol; and naphthol monomers such as naphthol, alkylnaphthol, and alkoxynaphthol.

[0084] The aforementioned coumarone resin is a resin that contains coumarone as a monomer component constituting the resin's skeleton (main chain). Other monomer components that may be included in the skeleton besides coumarone include styrene, α-methylstyrene, phenol, methylcoumarone, vinyltoluene, and the like.

[0085] The indene resin mentioned above is a resin that contains indene as a monomer component that constitutes the resin's backbone (main chain). Other monomer components that may be included in the backbone besides indene include styrene, α-methylstyrene, phenol, methylindene, vinyltoluene, and the like.

[0086] The aforementioned coumarone-indene resin is a resin containing coumarone and indene as monomer components that constitute the resin's backbone (main chain). Other monomer components that may be included in the backbone besides coumarone and indene include styrene, α-methylstyrene, phenol, methylcoumarone, vinyltoluene, and the like.

[0087] The aforementioned olefin resin has a main chain of olefin polymers such as ethylene, propylene, and 1-butene. Examples of the polyolefin resin include polyethylene, polypropylene, polybutene, cycloolefin resins, and copolymers of these resins. Among these, polyethylene, polypropylene, and ethylene-propylene copolymers are preferred, and polypropylene and ethylene-propylene copolymers are more preferred.

[0088] The polyurethane resin mentioned above refers to a resin having urethane bonds. This polyurethane resin can be synthesized, for example, from a polyol component and a polyisocyanate component. Examples of polyol components include polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide or propylene oxide to glycerin, polytetramethylene glycol, glycerin, ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, octanediol, polybutadiene polyol, polyisoprene polyol, and polyester polyol. Furthermore, examples of polyisocyanate components include isophorone diisocyanate (IPDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), crude diphenylmethane diisocyanate (crude MDI), hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, hexamethylene diisocyanate (HDI), and nurate-modified hexamethylene diisocyanate.

[0089] The acrylic resin is a resin obtained by polymerization of acrylic monomers such as acrylic acid, methacrylic acid, or derivatives thereof (acrylic acid esters, methacrylic acid esters, etc.). The main chain of the acrylic resin may be an all-acrylic type main chain obtained by polymerization of acrylic monomers such as acrylic acid, methacrylic acid, or derivatives thereof, or it may be a styrene-acrylic type main chain obtained by copolymerization of an acrylic monomer with a styrene monomer such as styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, etc. In one embodiment, the main chain of the acrylic resin is an all-acrylic type main chain.

[0090] The thermoplastic 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. Furthermore, from the viewpoint of processability, the thermoplastic 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. In this specification, the softening point of the thermoplastic resin is the temperature at which the sphere descends when the softening point specified in JIS K 6220-1:2015 (ISO 28641:2010) is measured using a ring-type softening point measuring device.

[0091] As the thermoplastic resin, commercially available products can be used. Examples of commercially available thermoplastic resins include those from ENEOS Corporation, Arakawa Chemical Industries, Ltd., ExxonMobil, Kraton Polymers, Yasuhara Chemical Co., Ltd., Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Corporation, Tosoh Corporation, Rutgers Chemicals, BASF, Kraton Polymers, Nippon Paint Chemicals Co., Ltd., Nippon Shokubai Co., Ltd., Taoka Chemical Industries, Ltd., and others.

[0092] The content of the thermoplastic resin is preferably in the range of 1 to 50 parts by mass per 100 parts by mass of the rubber component. If the content of the thermoplastic resin is 1 part by mass or more per 100 parts by mass of the rubber component, the viscoelasticity of the rubber composition can be controlled to a low level, and the wet performance is further improved. Also, if the content of the thermoplastic resin is 50 parts by mass or less per 100 parts by mass of the rubber component, the thermoplastic resin is less likely to precipitate from the rubber composition, and the effect of the thermoplastic resin can be fully expressed. Therefore, a tire rubber composition in which the thermoplastic resin content is 1 to 50 parts by mass per 100 parts by mass of the rubber component has further improved wet performance. Furthermore, from the viewpoint of abrasion resistance, the content of the thermoplastic resin is more preferably in the range of 5 to 40 parts by mass per 100 parts by mass of the rubber component, and even more preferably in the range of 10 to 30 parts by mass.

[0093] (Filler) The tire rubber composition of this embodiment preferably contains a filler. Including a filler improves the reinforcing properties of the rubber composition. Furthermore, as described above, in the tire rubber composition of this embodiment, the copolymer of cyclopentene and norbornene-based compound is characterized by having crosslinking points and by the entanglement of polymer chains. Generally, when a filler is blended with a rubber component, a reinforcing layer consisting of the filler and the rubber component is formed around the filler, and this reinforcing layer contributes to improving the reinforcing properties of the rubber composition, thereby improving wear resistance and other properties. When the tire rubber composition of this embodiment contains a filler, the reinforcing layer formed around the filler increases specifically due to the entanglement of polymer chains as described above, thus further improving wear resistance. Furthermore, when the tire rubber composition of this embodiment contains a filler, the reinforcing layer increases specifically due to the entanglement of polymer chains of the copolymer of cyclopentene and norbornene-based compound, which further reduces hysteresis loss and can further improve fuel efficiency.

[0094] The content of the filler is preferably in the range of 5 to 120 parts by mass per 100 parts by mass of the rubber component. If the filler content is 5 parts by mass or more per 100 parts by mass of the rubber component, the wear resistance of the rubber composition is further improved, and if it is 120 parts by mass or less, the fuel efficiency of the rubber composition is further improved. Therefore, a tire rubber composition in which the filler content is 5 to 120 parts by mass per 100 parts by mass of the rubber component has further improved fuel efficiency and wear resistance. Furthermore, from the viewpoint of wear resistance, the filler content is more preferably 10 parts by mass or more, even more preferably 20 parts by mass or more, and even more preferably 40 parts by mass or more, and from the viewpoint of fuel efficiency, it is more preferably 110 parts by mass or less, and even more preferably 100 parts by mass or less.

[0095] -Carbon Black- The filler preferably contains carbon black. The carbon black has a significant effect in reinforcing the rubber composition and improving its abrasion resistance. The carbon black is not particularly limited, and examples include GPF, FEF, HAF, ISAF, and SAF grade carbon black. These carbon blacks may be used individually or in combination of two or more. The carbon black content is preferably in the range of 5 to 120 parts by mass per 100 parts by mass of the rubber component. If the carbon black content is 5 parts by mass or more per 100 parts by mass of the rubber component, the abrasion resistance of the rubber composition is further improved, and if it is 120 parts by mass or less, the fuel efficiency of the rubber composition is further improved. From the viewpoint of abrasion resistance, the carbon black content is more preferably 10 parts by mass or more, even more preferably 20 parts by mass or more, and even more preferably 40 parts by mass or more per 100 parts by mass of the rubber component. From the viewpoint of fuel efficiency, it is more preferably 110 parts by mass or less, and even more preferably 100 parts by mass or less.

[0096] -Silica- The filler may also preferably contain silica. Including silica in the filler improves the fuel efficiency of the rubber composition. Examples of silica include wet silica (hydrated silica), dry silica (anhydrous silica), calcium silicate, aluminum silicate, etc., and among these, wet silica is preferred because it has a large amount of silanol groups. These silicas may be used individually or in combination of two or more. From the viewpoint of improving the wear resistance of the rubber composition and the tire to which it is applied, the silica content in the rubber composition is preferably 1 part by mass or more, and more preferably 3 parts by mass or more, per 100 parts by mass of rubber components. Furthermore, from the viewpoint of the fuel efficiency of the rubber composition, the silica content in the rubber composition is preferably 30 parts by mass or less, and more preferably 15 parts by mass or less, per 100 parts by mass of rubber components.

[0097] -Other Fillers- In addition to the carbon black and silica mentioned above, the filler may also contain other fillers. Examples of such other fillers include clay, talc, calcium carbonate, and aluminum hydroxide. The proportion of fillers other than carbon black and silica in the filler is preferably 30% by mass or less, and more preferably 15% by mass or less.

[0098] (Other) In addition to the rubber components, thermoplastic resins, and fillers described above, the rubber composition for tires of this embodiment may optionally contain various components commonly used in the rubber industry, such as silane coupling agents, antioxidants, hardened fatty acids, zinc oxide (zinc oxide), vulcanization accelerators, vulcanizing agents, etc., selected as appropriate within a range that does not impair the purpose of the present invention. Commercially available products can be suitably used as these compounding agents.

[0099] Examples of the silane coupling agents 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, and 3-triethoxysilylpropyl-N Examples include N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis(3-diethoxymethylsilylpropyl) tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, and dimethoxymethylsilylpropylbenzothiazolyl tetrasulfide. The content of the silane coupling agent is preferably in the range of 2 to 20 parts by mass, and more preferably in the range of 5 to 15 parts by mass, per 100 parts by mass of silica.

[0100] Examples of the aforementioned antioxidants include N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6C) and 2,2,4-trimethyl-1,2-dihydroquinoline polymer (TMDQ). These antioxidants may be used individually or in combination of two or more. There are no particular restrictions on the content of the antioxidant, but it is preferably in the range of 0.1 to 5 parts by mass, and more preferably 1 to 4 parts by mass, per 100 parts by mass of the rubber component.

[0101] Examples of the hardened fatty acid include stearic acid. The content of the hardened fatty acid is not particularly limited, but is preferably in the range of 0.1 to 5 parts by mass, and more preferably 1 to 4 parts by mass, per 100 parts by mass of the rubber component.

[0102] The content of the zinc oxide (zinc oxide) is not particularly limited, but is preferably in the range of 0.1 to 10 parts by mass, and more preferably 1 to 8 parts by mass, per 100 parts by mass of the rubber component.

[0103] Examples of the vulcanization accelerator include sulfenamide-based vulcanization accelerators, guanidine-based vulcanization accelerators, thiazole-based vulcanization accelerators, thiram-based vulcanization accelerators, and dithiocarbamate-based vulcanization accelerators. These vulcanization accelerators may be used individually or in combination of two or more. There are no particular restrictions on the content of the vulcanization accelerator, but it is preferably in the range of 0.1 to 5 parts by mass, and more preferably in the range of 0.2 to 4 parts by mass, per 100 parts by mass of the rubber component.

[0104] Examples of the vulcanizing agent include sulfur. The content of the vulcanizing agent is preferably in the range of 0.1 to 6 parts by mass, and more preferably in the range of 0.5 to 3 parts by mass, as sulfur, per 100 parts by mass of the rubber component.

[0105] (Method for manufacturing rubber composition for tires) The method for manufacturing the rubber composition for tires is not particularly limited, but for example, it can be manufactured by mixing the rubber components, thermoplastic resin and filler described above with various components as needed, and then kneading, heating, extruding, etc. The obtained rubber composition can be vulcanized by vulcanization.

[0106] There are no particular restrictions on the mixing conditions, and various conditions such as the input volume of the mixing device, the rotation speed of the rotor, the ram pressure, as well as the mixing temperature, mixing time, and the type of mixing device can be appropriately selected according to the purpose. Examples of mixing devices include Banbury mixers, intermixes, kneaders, and rolls, which are commonly used for mixing rubber compositions.

[0107] There are no particular restrictions on the heat treatment conditions, and various conditions such as heat treatment temperature, heat treatment time, and heat treatment equipment can be appropriately selected according to the purpose. Examples of such heat treatment equipment include heat treatment roll machines commonly used for heat treatment of rubber compositions.

[0108] There are no particular restrictions on the extrusion conditions, and various conditions such as extrusion time, extrusion speed, extrusion equipment, and extrusion temperature can be appropriately selected according to the purpose. Examples of extrusion equipment include extruders typically used for extruding rubber compositions. The extrusion temperature can be determined as appropriate.

[0109] There are no particular restrictions on the apparatus, method, and conditions for performing the vulcanization, and they can be appropriately selected according to the purpose. Examples of vulcanization apparatus include molding vulcanizers that use molds for vulcanizing rubber compositions. As for the vulcanization conditions, the temperature is, for example, around 100 to 190°C.

[0110] <Tire> The tire of this embodiment is characterized by containing the above-described tire rubber composition. Because the tire of this embodiment contains the above-described tire rubber composition, it is possible to achieve both wear resistance and wet performance while ensuring low fuel consumption. The part of the tire to which the rubber composition is applied is the tread rubber.

[0111] The tire of this embodiment may be obtained by molding an unvulcanized rubber composition and then vulcanizing it, depending on the type of tire to be applied, or by molding a semi-vulcanized rubber that has undergone a pre-vulcanization process, and then further vulcanizing it. The tire of this embodiment is preferably a pneumatic tire, and as the gas to fill the pneumatic tire, in addition to ordinary air or air with adjusted oxygen partial pressure, an inert gas such as nitrogen, argon, or helium can be used.

[0112] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way to the following examples.

[0113] <Method for synthesizing copolymer 1> Under a nitrogen atmosphere, 65 parts by mass of cyclopentene, 35 parts by mass of 2-norbornene, 300 parts by mass of cyclohexane, and 0.066 parts by mass of 1-hexene were added to a glass reaction vessel equipped with a stirrer. Next, 0.024 parts by mass of the ring-opening polymerization catalyst dichloro-(3-phenyl-1H-indene-1-ylidene)bis(tricyclohexylphosphine)ruthenium(II) dissolved in 1 part by mass of toluene was added, and the polymerization reaction was carried out at 20°C for 2 hours. After the polymerization reaction, the polymerization was stopped by adding an excess of vinyl ethyl ether. The polymerization solution was poured into a large excess of methanol containing 2,6-di-t-butyl-p-cresol (BHT), the precipitated polymer was recovered, washed with methanol, and then vacuum-dried at 50°C for 24 hours to obtain copolymer 167 parts by mass.

[0114] <Method for synthesizing copolymer 2> Under a nitrogen atmosphere, 77 parts by mass of cyclopentene, 23 parts by mass of dicyclopentadiene, 300 parts by mass of cyclohexane, and 0.069 parts by mass of 1-hexene were added to a glass reaction vessel equipped with a stirrer. Next, 0.024 parts by mass of the ring-opening polymerization catalyst dichloro-(3-phenyl-1H-indene-1-ylidene)bis(tricyclohexylphosphine)ruthenium(II) dissolved in 1 part by mass of toluene was added, and the polymerization reaction was carried out at 40°C for 2 hours. After the polymerization reaction, the polymerization was stopped by adding an excess of vinyl ethyl ether. The polymerization solution was poured into a large excess of methanol containing 2,6-di-t-butyl-p-cresol (BHT), the precipitated polymer was recovered, washed with methanol, and then vacuum-dried at 50°C for 24 hours to obtain 60 parts by mass of copolymer 2.

[0115] <Analysis of Copolymers> The molecular weight of each synthesized copolymer and the proportion of structural units derived from each monomer were measured using the method described below. The results are shown in Table 1.

[0116] (1) Weight-average molecular weight (Mw) The weight-average molecular weight (Mw) was measured using a gel permeation chromatography (GPC) system "HLC-8220" (Tosoh Corporation), with two H-type columns "HZ-M" (Tosoh Corporation) connected in series, using tetrahydrofuran as the solvent, at a column temperature of 40°C. A differential refractometer "RI-8320" (Tosoh Corporation) was used as the detector. The weight-average molecular weight (Mw) of the copolymer was measured as a polystyrene equivalent value.

[0117] (2) The proportion of structural units derived from each monomer that constitutes the copolymer, １ This was determined from 1H-NMR spectroscopy measurements.

[0118]

[0119] <Preparation of Rubber Compositions> Each component was mixed and kneaded according to the formulations shown in Table 2 to prepare the rubber compositions for the Examples and Comparative Examples.

[0120] In addition to the components shown in Table 2, each rubber composition was further formulated with the following additives per 100 parts by mass of rubber components: 1 part by mass of hardened fatty acid, 2.5 parts by mass of zinc oxide, 3.5 parts by mass of antioxidants (total amount of two types), 15 parts by mass of resin, 1.4 parts by mass of sulfenamide-based vulcanization accelerator, and 2 parts by mass of sulfur.

[0121] <Evaluation of Rubber Composition> The obtained rubber composition was evaluated for abrasion resistance using the following method, and further evaluated for wet performance and fuel efficiency. The results are shown in Table 2.

[0122] (3) Abrasion resistance In accordance with JIS K 6264-2:2005, the amount of abrasion was measured at room temperature with sandpaper attached to the polishing wheel and a slip ratio of 12% using a Lambourn abrasion tester manufactured by Ueshima Seisakusho. The evaluation results were indexed with the reciprocal of the amount of abrasion of Comparative Example 1 set to 100. A larger index value indicates less abrasion and superior abrasion resistance.

[0123] (4) For the wet performance vulcanized rubber, the loss tangent (tanδ) value was measured from -100°C to 70°C using a dynamic viscoelasticity testing machine (manufactured by TA Instruments) at a frequency of 15 Hz, dynamic strain of 0.1%, and a heating rate of 4°C / min, and a tanδ curve was obtained. The tanδ value at 0°C in the obtained tanδ curve was indexed with the value of Comparative Example 1 set to 100. The evaluation results indicate that a larger index value indicates better wet performance.

[0124] (5) Low Fuel Consumption The loss tangent (tanδ) of test specimens made from the obtained rubber composition was measured using a viscoelasticity measuring device (TA Instruments) under the conditions of a temperature of 50°C, a strain of 10%, and a frequency of 15 Hz. In addition, the modulus (M50) [MPa] of test specimens made from the obtained rubber composition at 50% strain was measured at room temperature. The evaluation results were indexed with the tanδ / M50 of Comparative Example 1 set to 100. A smaller index value indicates better fuel efficiency.

[0125]

[0126] *1 NR: Natural rubber *2 SBR: Modified styrene-butadiene rubber *3 Copolymer 1: Copolymer 1 of cyclopentene synthesized by the above method and norbornene compound (2-norbornene) *4 Copolymer 2: Copolymer 2 of cyclopentene synthesized by the above method and norbornene compound (dicyclopentadiene) *5 Silica: Specific gravity 1.950 g / cm³ ３ Silica *6 Carbon black: N234 grade carbon black *7 Aromatic hydrocarbon resin: Aromatic resin, manufactured by ENEOS Corporation, product name "Nisseki Neopolymer 140" *8 C ５ -C ９ Resin: Petroleum resin, manufactured by ENEOS Co., Ltd., product name “T-REZ RD104” *9 Hydrogenated C ５ Resin: Petroleum resin, manufactured by Synthomer Adhesive Technologies LLC, product name “Impera E1780” *10 C ９*11 Indene derivative resin *12 Hydrogenated DCPD resin: Petroleum-based resin (hydrogenated dicyclopentadiene resin), manufactured by ENEOS Material, product name "HA125" *13 Terpene-phenol resin: Terpene resin, manufactured by Yasuhara Chemical Co., Ltd., product name "YS Polystar S 145"

[0127] The results shown in Table 2 indicate that the rubber composition of the example, which includes a copolymer of cyclopentene and norbornene-based compound and a thermoplastic resin, provides improved abrasion resistance while ensuring good fuel efficiency. Furthermore, the rubber composition of the example demonstrates a balance between abrasion resistance and wet performance.

Claims

1. A rubber composition comprising a rubber component and a thermoplastic resin, wherein the rubber component comprises a copolymer of cyclopentene and a norbornene-based compound represented by the following general formula (1): [In the formula, R １ ~R ４ each independently represents a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a substituent containing a halogen atom, a silicon atom, an oxygen atom or a nitrogen atom, and R ２ and R ３ may be bonded to each other to form a ring, and m is an integer of 0 to 2.], a rubber composition for tires.

2. The tire rubber composition according to claim 1, wherein the content of the copolymer of cyclopentene and norbornene compound is 20 to 90 parts by mass per 100 parts by mass of the rubber component.

3. The tire rubber composition according to claim 1, wherein the copolymer of cyclopentene and norbornene compound has a weight-average molecular weight (Mw) of 200,000 to 1,000,000.

4. The tire rubber composition according to claim 1, wherein the copolymer of cyclopentene and norbornene compound has a content of cyclopentene-derived structural units of 20 to 75% by mass.

5. The tire rubber composition according to claim 1, wherein the copolymer of cyclopentene and norbornene-based compound has a content of 10 to 60% by mass of structural units derived from 2-norbornene.

6. The tire rubber composition according to claim 1, wherein the copolymer of cyclopentene and norbornene compound has a content of dicyclopentadiene-derived structural units of 10 to 60% by mass.

7. The tire rubber composition according to claim 1, wherein the content of the thermoplastic resin is 1 to 50 parts by mass per 100 parts by mass of the rubber component.

8. The tire rubber composition according to claim 1, wherein the thermoplastic resin is at least one selected from the group consisting of rosin resins, terpene resins, petroleum resins, phenolic resins, coal resins, xylene resins, aromatic resins, coumarone resins, indene resins, coumarone-indene resins, olefin resins, polyurethane resins, and acrylic resins.

9. The thermoplastic resin is C ５ based resin, C ９ based resin, C ５ -C ９ The tire rubber composition according to claim 1, which is at least one selected from the group consisting of resin-based resins and dicyclopentadiene-based resins.

10. The tire rubber composition according to claim 1, wherein the thermoplastic resin comprises at least one selected from the group consisting of rosin-based resins and terpene-based resins.

11. A tire characterized by comprising the tire rubber composition described in any one of claims 1 to 10.

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