Rubber composition for tires, and tire

Abstract

The present invention addresses the problem of providing a rubber composition for tires which ensure fuel-saving properties and have improved wear resistance. A solution to the above problem is a rubber composition for tires characterized in that: the composition comprises a rubber component and a filler; the rubber component comprises a copolymer of cyclopentene and a norbornene-based compound represented by general formula (1) [wherein R1 to R4 each independently represent a hydrogen atom, a C1-C20 hydrocarbon group, 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 is an integer of 0-2]; the rubber component further comprises at least one diene-based polymer which is different from the copolymer; the filler comprises silica; and the copolymer of cyclopentene and the norbornene-based compound comprises 10-60 mass% of structural units derived from the norbornene-based compound represented by general formula (1).

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' investigations revealed that even with the technologies described in Patent Documents 1 and 2, it is difficult to improve wear resistance while ensuring low fuel consumption, 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 improves wear resistance while ensuring low fuel consumption. Furthermore, the present invention aims to provide a tire that improves wear resistance 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 filler, 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 ２ and R ３The following are possible combinations of the two components to form a ring, where m is an integer from 0 to 2: a copolymer of a norbornene compound represented by [ ] and at least one diene polymer different from the copolymer, wherein the filler contains silica, and the copolymer of cyclopentene and the norbornene compound is characterized in that the content of structural units derived from the norbornene compound represented by the above general formula (1) is 10 to 60% by mass.

[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 30 to 90% 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 dicyclopentadiene-derived structural units of 10 to 60% by mass.

[0012] [6] The tire rubber composition according to any one of [1] to [5], wherein the content of the filler is 5 to 120 parts by mass per 100 parts by mass of the rubber component.

[0013] [7] The tire rubber composition according to any one of [1] to [6], wherein the proportion of silica in the filler is 10 to 100% by mass.

[0014] [8] The tire rubber composition according to any one of [1] to [7], wherein the diene polymer is at least one selected from the group consisting of isoprene polymer, styrene-butadiene copolymer, and butadiene polymer.

[0015] [9] The tire rubber composition according to any one of [1] to [8], wherein the diene polymer comprises a modified styrene-butadiene copolymer or a modified butadiene polymer.

[0016]

[10] A tire characterized by comprising a tire rubber composition described in any one of [1] to [9].

[0017] According to the present invention, it is possible to provide a rubber composition for tires that improves wear resistance while ensuring low fuel consumption. Furthermore, according to the present invention, it is possible to provide a tire that improves wear resistance while ensuring low fuel consumption.

[0018] The rubber composition for tires and the tires of the present invention will be described in detail below, based on embodiments thereof.

[0019] <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.

[0020] <Rubber Composition for Tires> The rubber composition for tires of this embodiment comprises a rubber component and a filler. In the rubber composition for tires of this embodiment, 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 ２ and R ３The copolymer comprises a copolymer of a norbornene-based compound represented by the above general formula (1) (also simply called a "cyclopentene and norbornene-based compound copolymer" or "polymer") and at least one diene polymer different from the copolymer, wherein the filler contains silica, and the copolymer of cyclopentene and norbornene-based compound is characterized in that the content of structural units derived from the norbornene-based compound represented by the above general formula (1) is 10 to 60% by mass.

[0021] In the tire rubber composition of this embodiment, the copolymer of cyclopentene and norbornene-based compound is characterized not only by having crosslinking points but also 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 abrasion resistance and other properties. In the tire rubber composition of this embodiment, the reinforcing layer formed around the filler is specifically increased due to the entanglement of polymer chains as described above, so abrasion resistance can be further improved. Furthermore, in the tire rubber composition of this embodiment, the specific increase in the reinforcing layer due to the entanglement of polymer chains of the copolymer of cyclopentene and norbornene-based compound reduces hysteresis loss, which can also improve fuel efficiency. Furthermore, in the tire rubber composition of this embodiment, the abrasion resistance of the rubber composition can be further improved by having a content ratio of structural units derived from the norbornene compound represented by the general formula (1) in the copolymer of cyclopentene and norbornene compound of 10% by mass or more. Moreover, in the tire rubber composition of this embodiment, the content ratio of structural units derived from the norbornene compound represented by the general formula (1) in the copolymer of cyclopentene and norbornene compound of 60% by mass or less lowers the glass transition temperature (Tg) of the copolymer and reduces the hysteresis loss (tanδ) of the rubber composition, thereby further improving fuel efficiency. Therefore, the tire rubber composition of this embodiment can improve abrasion resistance while ensuring fuel efficiency.

[0022] (Rubber Component) The rubber composition for a tire of the present embodiment contains a rubber component, and the rubber component imparts rubber elasticity to the composition. The rubber component of the rubber composition for a tire of the present embodiment includes a copolymer of cyclopentene and a norbornene-based compound represented by the above general formula (1), and at least one diene-based polymer different from the copolymer, and may further contain other rubbers.

[0023] - Copolymer of Cyclopentene and Norbornene-Based Compound - The copolymer of cyclopentene and norbornene-based compound includes a structural unit derived from cyclopentene and a structural unit derived from the norbornene-based compound represented by the above general formula (1). In addition, the copolymer of cyclopentene and norbornene-based compound is, in one preferred embodiment, a ring-opening copolymer, and particularly, a cyclopentene ring-opening copolymer. Also, the copolymer of cyclopentene and norbornene-based compound is, in one preferred embodiment, a linear polymer or a branched polymer, and particularly, a linear polymer.

[0024] In the above general formula (1), R １ to 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. Here, examples of the hydrocarbon group having 1 to 20 carbon atoms include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, neopentyl group, hexyl group, octyl group; alkenyl groups such as vinyl group, allyl group, 2-pentenyl group, 3-pentenyl group, 4-methyl-3-pentenyl group; aryl groups such as phenyl group, tolyl group, 2,6-dimethylphenyl group, 2,6-diisopropylphenyl group, naphthyl group; aralkyl groups such as benzyl group, phenethyl group; and the like.

[0025] 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 ２，６ Bicyclo[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 . 0 ２，７ ] 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, which have 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 [6.2.1.1３，６ 0 ２，７ tetracyclo[6.2.1.1 ３，６ 0 ２，７ dodeca-4-enes; bicyclo[2.2.1]hept-2-enes having a functional group containing a nitrogen atom such as 5-norbornene-2-carbonitrile, 5-norbornene-2-carboxamide, 5-norbornene-2,3-dicarboxylic acid imide; 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 dodeca-9-ene-4,5-dicarboxylic acid imide and the like having a functional group containing a nitrogen atom; tetracyclo[6.2.1.1 ３，６ 0 ２，７ dodeca-4-enes; bicyclo[2.2.1]hept-2-enes having a halogen atom such as 5-chloro-2-norbornene; 9-chlorotetracyclo[6.2.1.1 ３，６ 0 ２，７ dodeca-4-ene and the like having a halogen atom; tetracyclo[6.2.1.1 ３，６ 0 ２，７ dodeca-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 dodeca-9-ene, 4-triethoxysilyltetracyclo[6.2.1.1 ３，６ 0 ２，７ dodeca-9-ene and the like having a functional group containing a silicon atom; tetracyclo[6.2.1.1 ３，６ 0 ２，７ dodeca-4-enes; etc. are exemplified. The norbornene-based compound may be used alone or in combination of two or more.

[0026] As the norbornene compound represented by the above general formula (1), in the above general formula (1), those in which m is 0 or 1 are preferred, and those in which m is 0 are more preferred. Further, in the above general formula (1), R １ ~R ４ may be the same or different.

[0027] Among the norbornene 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 any group that does not form a ring, and is not particularly limited, and may be the same or different. As R １ ~R ４ , a hydrogen atom or an alkyl group having 1 to 3 carbon atoms is preferred. Also in this case, those in which m is 0 or 1 are preferred, and those in which m is 0 are more preferred. As the norbornene compound in which R １ ~R ４ in the above general formula (1) are 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, bicyclo[2.2.1]hept-2-enes having an unsubstituted or hydrocarbon substituent are preferred, and among them, 2-norbornene is particularly preferred.

[0028] Further, as the norbornene compound represented by the above general formula (1), a compound in which R ２ and R ３ are bonded to each other to form a ring is also preferred. Here, R ２ and R ３Specific 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.

[0029] The copolymer of cyclopentene and norbornene compound preferably contains 30 to 90% by mass of cyclopentene-derived structural units, more preferably 40 to 85% by mass, and even more preferably 50 to 80% 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 30 to 90% 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.

[0030] The copolymer of cyclopentene and norbornene compound has a content of structural units derived from the norbornene compound represented by the general formula (1) of 10 to 60% by mass, preferably 15 to 55% by mass, and more preferably 20 to 50% by mass, relative to the total repeating structural units of the copolymer. A content of 10% by mass or more of structural units derived from the norbornene compound represented by the general formula (1) in the copolymer improves the abrasion resistance of the rubber composition. Furthermore, a content of 60% by mass or less of structural units derived from the norbornene compound represented by the general formula (1) in the copolymer lowers the glass transition temperature (Tg) of the copolymer, reducing the hysteresis loss (tanδ) of the rubber composition containing the copolymer, thereby improving the fuel efficiency of the rubber composition.

[0031] 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.

[0032] 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.

[0033] When dicyclopentadiene is used as the norbornene compound represented by the above general formula (1), the copolymer of cyclopentene and the norbornene compound has a content ratio of dicyclopentadiene-derived structural units relative to the total repeating structural units of the copolymer, which in one embodiment is preferably 10 to 60% by mass, 15 to 55% by mass, and more preferably 20 to 50% by mass. By setting the content ratio of dicyclopentadiene-derived structural units in the copolymer to the 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.

[0034] 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.

[0035] 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.

[0036] 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).

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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).

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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".

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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)

[0053] 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).

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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).

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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 further improved.

[0063] -Diene Polymer- The rubber component includes at least one diene polymer different from the copolymer of cyclopentene and norbornene compound. By including the above-mentioned copolymer of cyclopentene and norbornene compound and at least one diene polymer different from said copolymer in the rubber component, it is possible to improve wear resistance while ensuring low fuel consumption. In this specification, the above-mentioned copolymer of cyclopentene and norbornene compound represented by the above general formula (1) is excluded from the term "diene polymer". That is, the rubber component of the tire rubber composition of this embodiment includes the above-mentioned copolymer of cyclopentene and norbornene compound and a diene polymer other than said copolymer.

[0064] The aforementioned diene polymer is a polymer that contains units derived from a diene compound as monomer units, and may be a homopolymer or a copolymer. Specifically, examples of diene compounds include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, and among these, 1,3-butadiene and isoprene are preferred.

[0065] Examples of the diene polymer include isoprene polymer, styrene-isoprene copolymer, styrene-butadiene copolymer, butadiene polymer, and chloroprene polymer. Here, examples of isoprene polymer include natural rubber (NR) and synthetic isoprene rubber (IR). Also, styrene-isoprene copolymer is also called styrene-isoprene rubber (SIR), styrene-butadiene copolymer is also called styrene-butadiene rubber (SBR), butadiene polymer is also called butadiene rubber (BR), and chloroprene polymer is also called chloroprene rubber (CR). Preferably, the diene polymer is at least one selected from the group consisting of isoprene polymer, styrene-butadiene copolymer, and butadiene polymer. A tire rubber composition containing the copolymer of cyclopentene and norbornene compound described above, and at least one selected from isoprene polymer, styrene-butadiene copolymer, and butadiene polymer, can further improve wear resistance while ensuring low fuel consumption.

[0066] The aforementioned diene polymer preferably includes a modified styrene-butadiene copolymer (hereinafter sometimes abbreviated as "modified SBR") or a modified butadiene polymer (hereinafter sometimes abbreviated as "modified BR"). Modified SBR and modified BR have high affinity for fillers and can improve the dispersibility of the fillers, thereby further improving the fuel efficiency and wear resistance of the rubber composition. Therefore, a tire rubber composition containing the above-mentioned copolymer of cyclopentene and norbornene-based compound and modified SBR or modified BR can further improve fuel efficiency and wear resistance. In addition, modified SBR has a high glass transition temperature (Tg) and also has the effect of suppressing uneven wear of the rubber composition. On the other hand, modified BR has a low glass transition temperature (Tg), and when combined with the above-mentioned copolymer of cyclopentene and norbornene-based compound, it can further improve the fuel efficiency and wear resistance of the rubber composition.

[0067] Examples of the modified functional groups in the modified SBR and modified BR include functional groups containing nitrogen, silicon, tin, and oxygen, with nitrogen-containing functional groups being preferred among them. When the modified SBR and modified BR have nitrogen-containing functional groups, their affinity with the filler is further increased, and the dispersibility of the filler can be further improved, thereby further improving the fuel efficiency and wear resistance of the rubber composition.

[0068] The functional group containing the nitrogen atom is preferably selected from the following: a monovalent hydrocarbon group having 1 to 30 carbon atoms, including a linear, branched, alicyclic, or aromatic ring, having a functional group selected from the group consisting of a primary amino group, a primary amino group protected by a hydrolyzable protecting group, an onium salt residue of a primary amine, an isocyanate group, a thioisocyanate group, an imine group, an imine residue, an amide group, a secondary amino group protected by a hydrolyzable protecting group, a cyclic secondary amino group, an onium salt residue of a cyclic secondary amine, an acyclic secondary amino group, an isocyanuric acid triester residue, a cyclic tertiary amino group, an acyclic tertiary amino group, a nitrile group, a pyridine residue, an onium salt residue of a cyclic tertiary amine, and an onium salt residue of an acyclic tertiary amine, and which may contain at least one heteroatom selected from an oxygen atom, a sulfur atom, and a phosphorus atom.

[0069] The modified SBR and modified BR can be obtained by using 1,3-butadiene or 1,3-butadiene and styrene as monomers and modifying the molecular ends and / or main chain of a polymer of 1,3-butadiene or a copolymer of 1,3-butadiene and styrene with a modifying agent, or by using 1,3-butadiene or 1,3-butadiene and styrene as monomers and polymerizing or copolymerizing these monomers using a polymerization initiator having a modifying functional group.

[0070] As the modifying agent, a hydrocarbyloxysilane compound is preferred, and as the hydrocarbyloxysilane compound, a compound represented by the following general formula (i) is preferred. １１ ａ-Si-(OR １２ ) ４－ａ ... (i)

[0071] In general formula (i), R １１ and R １２ Each independently represents a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, where a is an integer from 0 to 2, OR １２ If there are multiple ORs, each OR １２ These elements may be identical or different from each other, and the molecule does not contain an active proton.

[0072] As the hydrocarbyloxysilane compound, an aminoalkoxysilane compound represented by the following general formula (ii) is also preferred.

[0073] In general formula (ii), n1 + n2 + n3 + n4 = 4 (where n2 is an integer from 1 to 4, and n1, n3, and n4 are integers from 0 to 3). A １ This is at least one functional group selected from saturated cyclic tertiary amine compound residues, unsaturated cyclic tertiary amine compound residues, ketimine residues, nitrile groups, (thio)isocyanate groups, isocyanuric acid trihydrocarbyl ester groups, pyridine groups, (thio)ketone groups, amide groups, and first or second amino groups having hydrolyzable groups. When n4 is 2 or more, A １ They may be the same or different, A １ R may be a divalent group that bonds with Si to form a cyclic structure. ２１ R is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and may be the same or different when n1 is 2 or more. ２２ is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and may contain a nitrogen atom and / or a silicon atom. When n2 is 2 or more, R ２２ These elements may be identical or different from each other, or they may come together to form a ring. ２３R is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, or a halogen atom, and may be the same or different if n3 is 2 or more. ２４ This is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and may be the same or different when n4 is 2 or more. The hydrolyzable group in the first or second amino group having a hydrolyzable group is preferably a trimethylsilyl group or a tert-butyldimethylsilyl group, and the trimethylsilyl group is particularly preferred.

[0074] The aminoalkoxysilane compound represented by the above general formula (ii) is preferably an aminoalkoxysilane compound represented by the following general formula (iii).

[0075] In general formula (iii), p1 + p2 + p3 = 2 (where p2 is an integer between 1 and 2, and p1 and p3 are integers between 0 and 1). A ２ R is NRa (where Ra is a monovalent hydrocarbon group, a hydrolyzable group, or a nitrogen-containing organic group). ２５ R is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms. ２６ This is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, or a nitrogen-containing organic group, all of which may contain a nitrogen atom and / or a silicon atom. When p2 is 2, R ２６ These elements may be identical or different from each other, or they may come together to form a ring. ２７ R is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, or a halogen atom. ２８ This is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms. As the hydrolyzable group, a trimethylsilyl group or a tert-butyldimethylsilyl group is preferred, and a trimethylsilyl group is particularly preferred.

[0076] The aminoalkoxysilane compound represented by the above general formula (ii) is also preferably an aminoalkoxysilane compound represented by the following general formula (iv) or the following general formula (v).

[0077] In the general formula (iv), q1 + q2 = 3 (where q1 is an integer from 0 to 2, and q2 is an integer from 1 to 3). ３１ R is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms. ３２ and R ３３ Each of these is independently a hydrolyzable group, a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms. ３４ This is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and may be the same or different when q1 is 2. ３５ q2 is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and may be the same or different if q2 is 2 or more. A specific example of an aminoalkoxysilane compound represented by general formula (iv) is N,N-bis(trimethylsilyl)-3-[diethoxy(methyl)silyl]propylamine (also called "N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane").

[0078]

[0079] In the general formula (v), r1 + r2 = 3 (where r1 is an integer from 1 to 3, and r2 is an integer from 0 to 2). ３６ R is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms. ３７R is a dimethylaminomethyl group, a dimethylaminoethyl group, a diethylaminomethyl group, a diethylaminoethyl group, a methylsilyl(methyl)aminomethyl group, a methylsilyl(methyl)aminoethyl group, a methylsilyl(ethyl)aminomethyl group, a methylsilyl(ethyl)aminoethyl group, a dimethylsilylaminomethyl group, a dimethylsilylaminoethyl group, a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and may be the same or different when r1 is 2 or more. ３８ is a hydrocarbyloxy group having 1 to 20 carbon atoms, a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and when r2 is 2, it may be the same or different. A specific example of an aminoalkoxysilane compound represented by general formula (v) is N-(1,3-dimethylbutylidene)-3-triethoxysilyl-1-propaneamine.

[0080] The aminoalkoxysilane compound represented by the above general formula (ii) is also preferably an aminoalkoxysilane compound represented by the following general formula (vi) or the following general formula (vii).

[0081] In general formula (vi), R ４０ R is a trimethylsilyl group, a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms. ４１ R is a hydrocarbyloxy group having 1 to 20 carbon atoms, a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms. ４２ This is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms. Here, TMS represents a trimethylsilyl group (the same applies hereinafter).

[0082]

[0083] In general formula (vii), R ４３ and R ４４Each of these is independently a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms. ４５ R is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and each R ４５ They may be the same or different.

[0084] The aminoalkoxysilane compound represented by the above general formula (ii) is also preferably an aminoalkoxysilane compound represented by the following general formula (viiii) or the following general formula (ix).

[0085] In the general formula (viiii), s1 + s2 is 3 (where s1 is an integer from 0 to 2, and s2 is an integer from 1 to 3). ４６ R is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms. ４７ and R ４８ Each of these is independently a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms. ４７ or R ４８ They may be the same or different.

[0086]

[0087] In the general formula (ix), X is a halogen atom. ４９ R is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms. ５０ and R ５１ Each of these is independently a hydrolyzable group, a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, or R ５０ and R ５１ They are bonded together to form a divalent organic group. ５２ and R ５３Each of these is independently a halogen atom, a hydrocarbyl oxy group, a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms. ５０ and R ５１ As for the hydrolyzable group, a hydrolyzable group is preferred, and among the hydrolyzable groups, a trimethylsilyl group and a tert-butyldimethylsilyl group are preferred, with a trimethylsilyl group being particularly preferred.

[0088] The aminoalkoxysilane compound represented by the above general formula (ii) is also preferably an aminoalkoxysilane compound represented by the following general formula (x), the following general formula (xi), the following general formula (xii), or the following general formula (xiiii).

[0089] In general formulas (x) to (xiiii), u and v are integers from 0 to 2 and satisfying u + v = 2, respectively. ５４ ~ ９２ These may be the same or different, and are monovalent or divalent aliphatic or alicyclic hydrocarbon groups having 1 to 20 carbon atoms, or monovalent or divalent aromatic hydrocarbon groups having 6 to 18 carbon atoms. In general formula (xiiii), t1 and t2 are integers from 0 to 5.

[0090] Among the compounds satisfying general formula (x), general formula (xi), and general formula (xii), N1,N1,N7,N7-tetramethyl-4-((trimethoxysilyl)methyl)heptan-1,7-diamine, 2-((hexyl-dimethoxysilyl)methyl)-N1,N1,N3,N3-2-pentamethylpropane-1,3-diamine, N1-(3-(dimethylamino)propyl)-N3,N3-dimethyl-N1-(3-(trimethoxysilyl)propyl)propane-1,3-diamine, and 4-(3-(dimethylamino)propyl)-N1,N1,N7,N7-tetramethyl-4-((trimethoxysilyl)methyl)heptan-1,7-diamine are particularly preferred. Furthermore, among the compounds satisfying general formula (xiiii), N,N-dimethyl-2-(3-(dimethoxymethylsilyl)propoxy)ethanamine, N,N-bis(trimethylsilyl)-2-(3-(trimethoxysilyl)propoxy)ethanamine, N,N-dimethyl-2-(3-(trimethoxysilyl)propoxy)ethanamine, and N,N-dimethyl-3-(3-(trimethoxysilyl)propoxy)propane-1-amine are particularly preferred.

[0091] As the hydrocarbyloxysilane compound, compounds represented by the following general formula (xiv) are also preferred.

[0092] In the above general formula (xiv), A ３This is a monovalent group having at least one functional group selected from (thio)epoxy, (thio)isocyanate, (thio)ketone, (thio)aldehyde, imine, amide, isocyanuric acid trihydrocarbyl ester, (thio)carboxylic acid ester, metal salt of (thio)carboxylic acid, carboxylic acid anhydride, carboxylic acid halide, and dihydrocarbyl carbonate ester. Here, "(thio)epoxy" refers to epoxy and thioepoxy, "(thio)incyanate" refers to incyanate and thioincyanate, "(thio)ketone" refers to ketone and thioketone, "(thio)aldehyde" refers to aldehyde and thioaldehyde, "(thio)carboxylic acid ester" refers to carboxylic acid ester and thiocarboxylic acid ester, and "(thio)carboxylic acid metal salt" refers to metal salt of carboxylic acid and metal salt of thiocarboxylic acid. １０１ R is a single bond or a divalent inert hydrocarbon group, and the divalent inert hydrocarbon group preferably has 1 to 20 carbon atoms. １０２ and R １０３ Each independently represents a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, where n is an integer from 0 to 2, and R １０２ If there are multiple R １０２ They may be the same or different, OR １０３ If there are multiple ORs, １０３ These may be the same or different. Furthermore, the molecule of the hydrocarbyloxysilane compound represented by general formula (xiv) does not contain an active proton or an onium salt.

[0093] In the general formula (xiv), A ３ Among the functional groups in (thio)carboxylic acid, imines include ketimines, aldimines, and amidines, while (thio)carboxylic acid esters include unsaturated carboxylic acid esters such as acrylates and methacrylates. Furthermore, examples of metals in the metal salts of (thio)carboxylic acids include alkali metals, alkaline earth metals, Al, Sn, and Zn. １０１Among the divalent inert hydrocarbon groups, alkylene groups having 1 to 20 carbon atoms are preferred. The alkylene group may be linear, branched, or cyclic, but linear is particularly preferred. Examples of linear alkylene groups include methylene, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, octamethylene, decamethylene, dodecamethylene, and the like. １０２ and R １０３ Examples of alkyl groups include C1-C20 alkyl groups, C2-C18 alkenyl groups, C6-C18 aryl groups, and C7-C18 aralkyl groups. Here, the alkyl and alkenyl groups may be linear, branched, or cyclic, and examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, decyl, dodecyl, cyclopentyl, cyclohexyl, vinyl, propenyl, allyl, hexenyl, octenyl, cyclopentenyl, and cyclohexenyl groups. Furthermore, the aryl group may have substituents such as lower alkyl groups on the aromatic ring, and examples include phenyl, tolyl, xylyl, and naphthyl groups. Furthermore, the aralkyl group may have substituents such as lower alkyl groups on the aromatic ring, examples of which include benzyl groups, phenethyl groups, and naphthylmethyl groups. n is an integer from 0 to 2, but 0 is preferred, and it is necessary that the molecule does not contain active protons or onium salts.

[0094] Examples of hydrocarbyloxysilane compounds represented by the above general formula (xiv) include (thio)epoxy group-containing hydrocarbyloxysilane compounds such as 2-glycidoxyethyltrimethoxysilane, 2-glycidoxyethyltriethoxysilane, (2-glycidoxyethyl)methyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane (hereinafter also referred to as "GPMOS"), 3-glycidoxypropyltriethoxysilane, (3-glycidoxypropyl)methyldimethoxysilane, and 2-(3,4-epoxy). Preferred examples include cyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl(methyl)dimethoxysilane, 2-(3,4-epoxycyclohexyl)trimethoxysilane, and compounds thereof in which the epoxy group is replaced with a thioepoxy group. Among these, 3-glycidoxypropyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)trimethoxysilane are particularly preferred. Furthermore, as imine group-containing hydrocarbyl oxycyanide compounds, there are N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine, N-(1-methylethylidene)-3-(triethoxysilyl)-1-propanamine, N-ethylidene-3-(triethoxysilyl)-1-propanamine, N-(1-methylpropyridene)-3-(triethoxysilyl)-1-propanamine, N-(4-N,N-dimethylaminobenzylidene)-3-(triethoxysilyl)-1-propanamine, and N-(cyclohexyl Preferred examples include N-(1-methylpropylidene)-3-(triethoxysilyl)-1-propanamine and trimethoxysilyl compounds, methyldiethoxysilyl compounds, ethyldiethoxysilyl compounds, methyldimethoxysilyl compounds, and ethyldimethoxysilyl compounds corresponding to these triethoxysilyl compounds. Among these, N-(1-methylpropylidene)-3-(triethoxysilyl)-1-propanamine and N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine are particularly preferred.

[0095] As the modifying agent, a coupling agent represented by the following general formula (xv) is also preferred.

[0096] In the above general formula (xv), R １１１ , R １１２ and R １１３ Each of these independently represents a single bond or an alkylene group having 1 to 20 carbon atoms. １１４ , R １１５ , R １１６ , R １１７ and R １１９ Each of these independently represents an alkyl group having 1 to 20 carbon atoms. １１８ and R １２１ Each of these independently represents an alkylene group having 1 to 20 carbon atoms. １２０ R represents an alkyl or trialkylsilyl group having 1 to 20 carbon atoms. m represents an integer from 1 to 3, and p represents 1 or 2. １１１ ~R １２１ If there are multiple instances of m and p, they are independent of each other, and i, j, and k each independently represent integers from 0 to 6, where (i + j + k) is an integer from 3 to 10. ４ This represents an organic group having 1 to 20 carbon atoms, a hydrocarbon group, or at least one atom selected from the group consisting of oxygen, nitrogen, silicon, sulfur, and phosphorus atoms, and without active hydrogen. Here, in the above general formula (xv), A ４ The hydrocarbon groups represented include saturated, unsaturated, aliphatic, and aromatic hydrocarbon groups. Examples of organic groups that do not have active hydrogen include hydroxyl groups (-OH), secondary amino groups (>NH), and primary amino groups (-NH). ２ Examples include functional groups having active hydrogen, such as sulfhydryl groups (-SH), and organic groups that do not have active hydrogen.

[0097] The coupling agent represented by the general formula (xv) is preferably at least one selected from the group consisting of tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, and tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane.

[0098] As the modifying agent, a coupling agent represented by the following general formula (xvi) is also preferred. (R １２６ ) ｂ ZX ｃ ... (xvi)

[0099] In the above general formula (xvi), Z is tin or silicon, and X is chlorine or bromine. １２６ R is selected from the group consisting of alkyl groups having 1 to 20 carbon atoms, cycloalkyl groups having 3 to 20 carbon atoms, aryl groups having 6 to 20 carbon atoms, and aralkyl groups having 7 to 20 carbon atoms. Here, R １２６ Specifically, examples include methyl group, ethyl group, n-butyl group, neophyll group, cyclohexyl group, n-octyl group, and 2-ethylhexyl group. b is 0 to 3 and c is 1 to 4, where b + c = 4.

[0100] The coupling agent represented by the above general formula (xvi) is tin tetrachloride, (R １２６ ) SnCl ３ , (R １２６ ) ２ SnCl ２ , (R １２６ ) ３ SnCl and silicon tetrachloride are preferred, and among these, tin tetrachloride is particularly preferred.

[0101] Lithium amide compounds are preferred as polymerization initiators having the aforementioned modified functional group. Examples of lithium amide compounds include lithium hexamethyleneimide, lithium pyrrolidide, lithium piperidide, lithium heptamethyleneimide, lithium dodecamethyleneimide, lithium dimethylamide, lithium diethylamide, lithium dibutylamide, lithium dipropylamide, lithium diheptylamide, lithium dihexylamide, lithium dioctylamide, lithium di-2-ethylhexylamide, lithium didecylamide, lithium-N-methylpiperazide, lithium ethylpropylamide, lithium ethylbutylamide, lithium ethylbenzylamide, and lithium methylphenethylamide.

[0102] Furthermore, as the lithium amide compound, the formula is Li-AM [wherein AM is the following formula (xvii): (In the formula, R １３１ and R １３２ Each of these is independently an alkyl group, cycloalkyl group, or aralkyl group having 1 to 12 carbon atoms. ) A substituted amino group represented by the following formula (xviiii): (In the formula, R １３３ This represents an alkylene group, a substituted alkylene group, an oxyalkylene group, or an N-alkylaminoalkylene group having 3 to 16 methylene groups. By using a lithium amide compound represented by [], modified SBR and modified BR can be obtained into which at least one nitrogen-containing functional group selected from the group consisting of a substituted amino group represented by formula (xvii) and a cyclic amino group represented by formula (xviiii) is introduced.

[0103] In the above equation (xvii), R １３１ and R １３２ R is an alkyl group, cycloalkyl group, or aralkyl group having 1 to 12 carbon atoms, and specifically, methyl group, ethyl group, butyl group, octyl group, cyclohexyl group, 3-phenyl-1-propyl group, and isobutyl group are preferred examples. １３１ and R １３２ These can be the same or different.

[0104] In the above equation (xviiii), R １３３ This is an alkylene group, a substituted alkylene group, an oxyalkylene group, or an N-alkylaminoalkylene group having 3 to 16 methylene groups. Here, the substituted alkylene group includes monosubstituted to octasubstituted alkylene groups, and the substituents include linear or branched alkyl groups, cycloalkyl groups, bicycloalkyl groups, aryl groups, and aralkyl groups having 1 to 12 carbon atoms. Also, R １３３ Specifically, trimethylene groups, tetramethylene groups, hexamethylene groups, oxydiethylene groups, N-alkylazadiethylene groups, dodecamethylene groups, and hexadecamethylene groups are preferred.

[0105] The lithium amide compound may be pre-prepared from a secondary amine and a lithium compound and used in the polymerization reaction, or it may be generated in the polymerization system. Examples of the secondary amine include dimethylamine, diethylamine, dibutylamine, dioctylamine, dicyclohexylamine, diisobutylamine, as well as azacycloheptane (also called "hexamethyleneimine (HMI)"), 2-(2-ethylhexyl)pyrrolidine, 3-(2-propyl)pyrrolidine, 3,5-bis(2-ethylhexyl)piperidine, 4-phenylpiperidine, 7-decyl-1-azacyclotridecane, 3,3-dimethyl-1-azacyclotetradecane, 4-dodecyl-1-azacyclooctane, 4-(2-phenylbutyl)-1-azacyclooctane, 3-ethyl-5-cyclohexyl-1-azacycloheptane, 4-hexyl-1-azacycloheptane, 9 Examples of cyclic amines include isoamyl-1-azacycloheptadecane, 2-methyl-1-azacycloheptadecene-9-ene, 3-isobutyl-1-azacyclododecane, 2-methyl-7-tert-butyl-1-azacyclododecane, 5-nonyl-1-azacyclododecane, 8-(4'-methylphenyl)-5-pentyl-3-azabicyclo[5.4.0]undecane, 1-butyl-6-azabicyclo[3.2.1]octane, 8-ethyl-3-azabicyclo[3.2.1]octane, 1-propyl-3-azabicyclo[3.2.2]nonane, 3-(tert-butyl)-7-azabicyclo[4.3.0]nonane, and 1,5,5-trimethyl-3-azabicyclo[4.4.0]decane. Furthermore, as the lithium compound, you can use ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, tert-octyllithium, n-decyllithium, phenyllithium, 2-naphthyllithium, 2-butylphenyllithium, 4-phenylbutyllithium, cyclohexyllithium, cyclopentyllithium, or hydrocarbyl lithium such as the reaction product of diisopropenylbenzene and butyllithium.

[0106] In the production of the modified SBR and modified BR, anionic polymerization using the above-mentioned polymerization initiator having a modified functional group or the lithium compound (i.e., a polymerization initiator without a modified functional group) may be used, but the polymerization reaction mechanism is not limited to this, and coordination polymerization may be used, for example. When producing modified SBR and modified BR by coordination polymerization, it is preferable to use a rare earth metal compound as the polymerization initiator, and it is even more preferable to use a combination of the following components (a), (b), and (c).

[0107] The component (a) used in the coordination polymerization is selected from rare earth metal compounds and complex compounds of rare earth metal compounds and Lewis bases. Examples of rare earth metal compounds include carboxylates, alkoxides, β-diketone complexes, phosphates, and phosphates of rare earth elements, and examples of Lewis bases include acetylacetone, tetrahydrofuran, pyridine, N,N-dimethylformamide, thiophene, diphenyl ether, triethylamine, organophosphorus compounds, and monovalent or divalent alcohols. Preferred rare earth elements in the rare earth metal compounds are lanthanum, neodymium, praseodymium, samarium, and gadolinium, with neodymium being particularly preferred among these. Specifically, examples of component (a) include neodymium versatate, neodymium tri-2-ethylhexanoate, complex compounds of the same with acetylacetone, neodymium trineodecanoate, complex compounds of the same with acetylacetone, and neodymium tri-n-butoxide.

[0108] The component (b) used in the coordination polymerization is selected from organoaluminum compounds. Specifically, examples of such organoaluminum compounds include trihydrocarbyl aluminum compounds, hydrocarbyl aluminum hydrides, and hydrocarbyl aluminoxane compounds having hydrocarbon groups with 1 to 30 carbon atoms. Specifically, examples of such organoaluminum compounds include trialkylaluminum, dialkylaluminum hydride, alkylaluminum dihydride, and alkylaluminoxane. It is preferable to use aluminoxane and other organoaluminum compounds in combination as component (b).

[0109] The component (c) used in the coordination polymerization is selected from compounds having hydrolyzable halogens or complex compounds of these with Lewis bases; organic halides having tertiary alkyl halides, benzyl halides, or allyl halides; ionic compounds consisting of non-coordinating anions and countercations, etc. Specific examples of such component (c) include alkylaluminum dichlorides, dialkylaluminum chlorides, silicon tetrachloride, tin tetrachloride, complexes of zinc chloride with Lewis bases such as alcohols, complexes of magnesium chloride with Lewis bases such as alcohols, benzyl chloride, t-butyl chloride, benzyl bromide, t-butyl bromide, triphenylcarbonium tetrakis(pentafluorophenyl) borate, etc.

[0110] Furthermore, the modified SBR and modified BR may be reacted with a modifying agent such as a hydrocarbyloxysilane compound, and then with a condensation accelerator containing a metal element, or at least one selected from the group consisting of inorganic acids and metal halides. By reacting with the condensation accelerator containing a metal element, or at least one selected from the group consisting of inorganic acids and metal halides, modified SBR and modified BR with high Mooney viscosity and excellent dimensional stability can be produced.

[0111] As the condensation accelerator containing the aforementioned metal element, it is preferable to use a metal compound containing at least one metal from groups 2 to 15 of the periodic table. Specific examples of metal elements include titanium, zirconium, aluminum, bismuth, and tin. Furthermore, as the condensation accelerator containing the aforementioned metal element, alkoxides, carboxylates, or acetylacetonate complex salts of the above-mentioned metals are preferred. Specifically, preferred condensation accelerators include tetrakis(2-ethyl-1,3-hexanediolato)titanium, tetrakis(2-ethylhexyloxy)titanium (hereinafter also referred to as "tetra-2-ethylhexyl titanate" or "EHOTi"), tetra(octanediolate)titanium, tris(2-ethylhexanoate)bismuth, tetra-n-propoxyzirconium, tetra-n-butoxyzirconium, bis(2-ethylhexanoate)zirconium oxide, bis(oleate)zirconium oxide, tri-i-propoxyaluminum, trisec-butoxyaluminum, tris(2-ethylhexanoate)aluminum, tris(stearate)aluminum, zirconium tetrakis(acetylacetonate), aluminum tris(acetylacetonate), bis(2-ethylhexanoate)tin, di-n-octyltin bis(2-ethylhexylmalate), and the like.

[0112] On the other hand, examples of the inorganic acid include hydrochloric acid, sulfuric acid, and phosphoric acid. Furthermore, as the metal halide, a metal halide containing at least one metal from groups 2 to 15 of the periodic table can be suitably used, and it is even more preferable to use a halide containing at least one metal atom selected from the group consisting of silicon, tin, aluminum, zinc, titanium, and zirconium. Specifically, preferred metal halides include trimethylsilyl chloride, dimethyldichlorosilane, methyltrichlorosilane, silicon tetrachloride, methyldichlorosilane, tin tetrachloride, diethylaluminum chloride, ethylaluminum sesquichloride, ethylaluminum dichloride, zinc chloride, titanium tetrachloride, titanocene dichloride, zirconium tetrachloride, and zirconocene dichloride. It is preferable to carry out the reaction with the inorganic acid and metal halide in the presence of water. The water may be used in the form of elemental water, a solution of alcohol or other solvent, or dispersed micelles in a hydrocarbon solvent.

[0113] Furthermore, the modified SBR and modified BR may be stabilized by reacting them with a modifying agent such as a hydrocarbyloxysilane compound, and then reacting them with a carboxylic acid partial ester of a polyhydric alcohol. Here, the carboxylic acid partial ester of a polyhydric alcohol means a partial ester of a polyhydric alcohol and a carboxylic acid, and having one or more hydroxyl groups. Specifically, esters of sugars or modified sugars having four or more carbon atoms and fatty acids are preferably used. More preferably, these esters include (1) fatty acid partial esters of polyhydric alcohols, particularly partial esters of saturated or unsaturated higher fatty acids having 10 to 20 carbon atoms and polyhydric alcohols (monoesters, diesters, or triesters), and (2) ester compounds in which one to three partial esters of polyhydric carboxylic acids and higher alcohols are bonded to a polyhydric alcohol. The polyhydric alcohol used as a raw material for the partial ester is preferably a sugar having five or six carbon atoms and at least three hydroxyl groups (which may or may not be hydrogenated), glycols, or polyhydroxy compounds. Furthermore, the raw material fatty acid is preferably a saturated or unsaturated fatty acid having 10 to 20 carbon atoms, for example, stearic acid, lauric acid, and palmitic acid are used. Among the fatty acid partial esters of the polyhydric alcohol, sorbitan fatty acid esters are preferred, specifically sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, and the like.

[0114] The content of the diene polymer is preferably 10 to 80 parts by mass, and more preferably 15 to 70 parts by mass, per 100 parts by mass of the rubber component. When the content of the diene polymer is 10 to 80 parts by mass or more per 100 parts by mass of the rubber component, the balance between the low fuel consumption and abrasion resistance of the rubber composition is further improved.

[0115] -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.

[0116] (Filler) The tire rubber composition of this embodiment includes a filler. The inclusion of the filler improves the reinforcing properties of the rubber composition.

[0117] 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.

[0118] -Silica- The filler contains silica. The inclusion of silica in the filler improves the fuel efficiency of the rubber composition.

[0119] Examples of the silica include wet silica (hydrated silica), dry silica (anhydrous silica), calcium silicate, and aluminum silicate. Among these, wet silica is preferred because it has a high concentration of silanol groups. These silicas may be used individually or in combination of two or more. Commercially available silica can be used, and examples of such commercially available silica include products from Tosoh Silica Co., Ltd., Evonik, Solvay, Solvay Japan Ltd., and Tokuyama Corporation.

[0120] The proportion of silica in the filler is preferably 10 to 100% by mass. When the proportion of silica in the filler is 10% by mass or more, a good balance can be achieved between the wear resistance and fuel efficiency of the rubber composition. Therefore, a tire rubber composition in which the proportion of silica in the filler is 10 to 100% by mass has a good balance between wear resistance and fuel efficiency, and can further improve wear resistance while maintaining fuel efficiency. From the viewpoint of wear resistance and fuel efficiency of the rubber composition, the proportion of silica in the filler is more preferably 20% by mass or more, and even more preferably 30% by mass or more.

[0121] -Other Fillers- In addition to the silica described above, the filler may also contain other fillers. Examples of such other fillers include carbon black, clay, talc, calcium carbonate, and aluminum hydroxide. Among these, carbon black is preferred as the other filler. The proportion of carbon black in the filler is preferably in the range of 5 to 60% by mass. Furthermore, the proportion of fillers other than silica in the filler is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or more.

[0122] (Other) In addition to the rubber components and fillers described above, the tire rubber composition 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), tackifiers, 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] Examples of the tackifier include rosin resins, terpene resins, petroleum resins, phenolic resins, coal resins, xylene resins, etc., and among these, petroleum resins are preferred. As for the petroleum resin, C ５ based resin, C ５ -C ９ based resin, C ９ Examples include resins and dicyclopentadiene resins. The content of the tackifier is not particularly limited, but is preferably in the range of 0.1 to 5 parts by mass, and more preferably 0.5 to 3 parts by mass, per 100 parts by mass of the rubber component.

[0128] 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.

[0129] 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.

[0130] (Method for manufacturing tire rubber composition) The method for manufacturing the tire rubber composition is not particularly limited, but for example, it can be manufactured by mixing the rubber components and fillers described above with various components as needed, and then kneading, heating, extruding, etc. The obtained rubber composition can be vulcanized by vulcanization.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] <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 improve wear resistance while ensuring low fuel consumption. The part of the tire to which the rubber composition is applied is the tread rubber.

[0136] 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.

[0137] 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.

[0138] <Method for synthesizing copolymer 1> Under a nitrogen atmosphere, 88 parts by mass of cyclopentene, 12 parts by mass of dicyclopentadiene, 300 parts by mass of cyclohexane, and 0.032 parts by mass of 1-hexene were added to a glass reaction vessel equipped with a stirrer. Next, 0.025 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 copolymer 154 parts by mass.

[0139] <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.

[0140] <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.

[0141] (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.

[0142] (2) The proportion of structural units derived from each monomer that constitutes the copolymer, １ This was determined from 1H-NMR spectroscopy measurements.

[0143]

[0144] <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.

[0145] 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, 2.5 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.

[0146] <Evaluation of Rubber Composition> The obtained rubber composition was evaluated for abrasion resistance and fuel efficiency using the following method. The results are shown in Table 2.

[0147] (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.

[0148] (4) 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.

[0149]

[0150] *1 NR: Natural rubber *2 Modified SBR: Modified styrene-butadiene copolymer *3 Copolymer 1: Copolymer 1 of cyclopentene synthesized by the above method and norbornene compound (dicyclopentadiene) *4 Copolymer 2: Copolymer 2 of cyclopentene synthesized by the above method and norbornene compound (dicyclopentadiene) *5 Carbon black: N234 grade carbon black *6 Silica: Specific gravity 1.950 g / cm³ ３ silica

[0151] The results shown in Table 2 indicate that the rubber composition of the example, which includes a copolymer of cyclopentene and a norbornene compound having a structural unit content of 10 to 60% by mass of norbornene-derived structural units, a diene polymer different from the copolymer, and silica, provides improved abrasion resistance while ensuring good fuel efficiency.

Claims

1. A rubber component and a filler, wherein the rubber component is 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 ２ and R ３ The following are possible combinations of the two components to form a ring, where m is an integer from 0 to 2: a copolymer of a norbornene compound represented by [ ] and at least one diene polymer different from the copolymer, wherein the filler contains silica, and the copolymer of cyclopentene and the norbornene compound is characterized in that the content of structural units derived from the norbornene compound represented by the above general formula (1) is 10 to 60% by mass.

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-based compound has a content of 30 to 90% by mass of structural units derived from cyclopentene.

5. 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.

6. The tire rubber composition according to claim 1, wherein the content of the filler is 5 to 120 parts by mass per 100 parts by mass of the rubber component.

7. The tire rubber composition according to claim 1, wherein the proportion of silica in the filler is 10 to 100% by mass.

8. The tire rubber composition according to claim 1, wherein the diene polymer is at least one selected from the group consisting of isoprene polymer, styrene-butadiene copolymer, and butadiene polymer.

9. The tire rubber composition according to claim 1, wherein the diene polymer comprises a modified styrene-butadiene copolymer or a modified butadiene polymer.

10. A tire characterized by comprising the tire rubber composition described in any one of claims 1 to 9.

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