Rubber composition and tire

Abstract

To provide a rubber composition and a tire which improve total performance of wear resistance, rubber strength, wet grip performance, high-speed wet grip performance and low fuel consumption.SOLUTION: A rubber composition contains a modified polymer extended rubber obtained by extending a rubber composition A with at least one kind of modified polymer selected from the group consisting of a modified resin including a functional group having affinity with silica, and a modified thermoplastic elastomer including a functional group having affinity with silica.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a rubber composition and a tire. [Background technology]

[0002] In tires, technology has been proposed to incorporate large amounts of silica to improve wear resistance and wet performance, but there is room for improvement, as there are problems with processability and insufficient silica dispersion resulting in problems with rubber strength. Summary of the Invention [Problem to be solved by the invention]

[0003] For this reason, for example, when a large amount of plasticizers such as oils and resins are compounded in order to improve processability and silica dispersibility, the Tg and tan δ of the entire rubber composition increase, resulting in a deterioration in fuel economy. In addition, as the plasticizer is compounded, a new problem arises in that the rubber component deteriorates due to precipitation from the rubber component. An object of the present invention is to solve the above problems and to provide a rubber composition and a tire which improve the overall performance of wear resistance, rubber strength, wet grip performance, high-speed wet grip performance and fuel economy. [Means for solving the problem]

[0004] The present invention relates to a rubber composition comprising a modified polymer-extended rubber in which a rubber component A is extended with at least one modified polymer selected from the group consisting of a modified resin having a functional group that has affinity for silica, and a modified thermoplastic elastomer having a functional group that has affinity for silica.

[0005] The rubber component A preferably has a number average molecular weight of 150,000 or more.

[0006] The functional group is preferably at least one selected from the group consisting of a group represented by SiOR (R is a hydrogen atom or a hydrocarbon group), an alkoxysilyl group, an amino group, a hydroxyl group, an epoxy group, and a carboxyl group, which may have a substituent.

[0007] The rubber component A preferably has a glass transition temperature of -10°C or lower.

[0008] The resin constituting the skeleton of the modified resin is preferably at least one selected from the group consisting of C5 resins, C5-C9 resins, C9 resins, terpene resins, terpene-aromatic compound resins, rosin resins, dicyclopentadiene resins, and alkylphenol resins.

[0009] The thermoplastic elastomer constituting the skeleton of the modified thermoplastic elastomer preferably has a block made of an aromatic vinyl monomer.

[0010] The rubber component A preferably contains a modified rubber having a functional group having affinity for silica.

[0011] The rubber component A preferably contains at least one rubber selected from the group consisting of styrene-butadiene rubber and butadiene rubber.

[0012] The modified polymer-extended rubber is preferably produced by preparing the rubber component A by polymerization in an organic solvent, and adding a solution of the modified resin and / or the modified thermoplastic elastomer to the solution obtained after polymerization.

[0013] The content of the liquid plasticizer per 100 parts by mass of the total rubber component is preferably 20 parts by mass or less.

[0014] The content of the liquid plasticizer per 100 parts by mass of the total rubber component is preferably 10 parts by mass or less.

[0015] The content of silica per 100 parts by mass of the total rubber component is preferably 30 parts by mass or more.

[0016] The content of silica per 100 parts by mass of the total rubber component is preferably 80 parts by mass or more.

[0017] The present invention relates to a tire having a tread rubber layer, the tread rubber layer having at least a surface-side tread rubber layer arranged on a surface side of the tire, and an inner tread rubber layer arranged radially inward of the surface-side tread rubber layer, the surface-side tread rubber layer being made of the above-mentioned rubber composition, and the inner tread rubber layer being made of a rubber composition different from the above-mentioned rubber composition.

[0018] It is preferable that the rubber composition constituting the surface side tread rubber layer and the rubber composition constituting the inner tread rubber layer each contain 20 parts by mass or less of liquid plasticizer relative to 100 parts by mass of the total rubber component. Effect of the Invention

[0019] According to the present invention, the rubber composition contains a modified polymer-extended rubber in which rubber component A is extended with at least one modified polymer selected from the group consisting of modified resins having functional groups that have affinity with silica and modified thermoplastic elastomers having functional groups that have affinity with silica, and therefore the overall performance of the rubber composition can be improved in terms of abrasion resistance, rubber strength, wet grip performance, high-speed wet grip performance and fuel economy. [Brief description of the drawings]

[0020] [Figure 1] 1 is a cross-sectional view showing a portion of a passenger vehicle tire according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The present invention provides a rubber composition comprising a modified polymer-extended rubber obtained by extending a rubber component A with at least one modified polymer selected from the group consisting of a modified resin having a functional group with affinity for silica and a modified thermoplastic elastomer having a functional group with affinity for silica. The use of the modified polymer-extended rubber improves the overall performance of abrasion resistance, rubber strength, wet grip performance, high-speed wet grip performance, and fuel economy.

[0022] The mechanism by which the above-mentioned effects are obtained is not clear, but is presumed to be as follows. Adding plasticizers such as oil to improve the processability of rubber may lead to a decrease in abrasion resistance and wet grip performance. In order to prevent this, when rubber is mixed with modified resins or modified thermoplastic elastomers having functional groups with affinity for silica in a normal kneading process, the modified resins / modified thermoplastic elastomers are difficult to disperse in the rubber due to the influence of the functional groups (=hydrophilic functional groups) that act on silica. In contrast, when rubber that has been extended in advance by modified resins / modified thermoplastic elastomers is used, such a situation is unlikely to occur, and as a result, it is considered that the action of the modifying groups improves the dispersion of silica in the kneading process. Therefore, it is presumed that the use of the modified polymer-extended rubber improves the overall performance of abrasion resistance, rubber strength, wet grip performance, high-speed wet grip performance, and fuel efficiency.

[0023] [Modified polymer-extended rubber] The modified polymer-extended rubber is obtained by extending rubber component A with at least one modified polymer selected from the group consisting of modified resins having a functional group with affinity for silica and modified thermoplastic elastomers having a functional group with affinity for silica. The term "affinity for silica" is defined as a general term for the property of generating a covalent bond between the functional group and the surface of the silica, or an intermolecular force weaker than a covalent bond (electromagnetic forces acting between molecules, such as ion-dipole interaction, dipole-dipole interaction, hydrogen bond, van der Waals force, ionic bond, etc.).

[0024] (Modified polymer that constitutes modified polymer-extended rubber) In at least one modified polymer selected from the group consisting of modified resins having a functional group with affinity to silica and modified thermoplastic elastomers having a functional group with affinity to silica, the resin constituting the skeleton of the modified resin having a functional group with affinity to silica is not particularly limited, and known resins can be used.As the resin, for example, thermoplastic resins such as C5 resins, C5-C9 resins, C9 resins, terpene resins, terpene-aromatic compound resins, rosin resins, dicyclopentadiene resins, and alkylphenol resins can be suitably used.

[0025] Examples of C5 resins include C5 synthetic petroleum resins, such as aliphatic petroleum resins obtained by polymerizing a C5 fraction obtained by thermal cracking of naphtha in the petrochemical industry using a Friedel-Crafts catalyst such as AlCl3 or BF3. C5 fractions usually include olefinic hydrocarbons such as 1-pentene, 2-pentene, 2-methyl-1-butene, 2-methyl-2-butene, and 3-methyl-1-butene; diolefinic hydrocarbons such as 2-methyl-1,3-butadiene, 1,2-pentadiene, 1,3-pentadiene, and 3-methyl-1,2-butadiene; and the like. Commercially available C5 resins can be used, such as T-REZ RA100 (manufactured by Tonen Chemical Industry Co.), Escorez 1000 series (manufactured by ExxonMobil Chemical Corporation), and Quinton 100 series A100, B170, M100, and R100 (manufactured by Zeon Corporation).

[0026] Examples of C5-C9 resins include C5-C9 synthetic petroleum resins, such as solid polymers obtained by polymerizing petroleum-derived C5 fractions and C9 fractions using Friedel-Crafts catalysts such as AlCl3 and BF3. Specific examples include copolymers mainly composed of styrene, vinyltoluene, α-methylstyrene, indene, etc. Commercially available C5-C9 resins include T-REZ RD104 (manufactured by Tonen Chemical Industry Co., Ltd.), ECR213 (manufactured by ExxonMobil Chemical Co., Ltd.), and Quinton G100B (manufactured by Zeon Corporation).

[0027] C9 resins are by-produced C9 fractions produced by thermal decomposition of naphtha in the petrochemical industry together with basic petrochemical raw materials such as ethylene and propylene, and include resins polymerized from aromatics having a carbon number of 9, with vinyltoluene, alkylstyrene, and indene as the main monomer. Specific examples of C9 fractions include vinyltoluene, α-methylstyrene, β-methylstyrene, γ-methylstyrene, o-methylstyrene, p-methylstyrene, and indene. C9 resins include C8 fractions such as styrene, C9 fractions, and C8 fractions such as styrene, C9 fractions, and C9 fractions. 10 The fractions methylindene, 1,3-dimethylstyrene, and even naphthalene, vinylnaphthalene, vinylanthracene, p-tert-butylstyrene are used as raw materials, and these C8-C 10 The fractions and the like can be copolymerized as a mixture with, for example, a Friedel-Crafts catalyst to obtain the C9 resin. Commercially available C9 resins can be used, and examples of C9 petroleum resins include Nippon Oil Neopolymer L-90, Nippon Oil Neopolymer 120, Nippon Oil Neopolymer 130, and Nippon Oil Neopolymer 140 (manufactured by JX Nippon Oil & Energy Corporation).

[0028] Terpene resins include turpentine oil obtained at the same time as rosin is obtained from pine trees, or solid resins obtained by blending polymerizable components separated from this and polymerizing them using a Friedel-Crafts catalyst. Specific examples include β-pinene resin and α-pinene resin. Commercially available terpene resins include the YS Resin series (manufactured by Yasuhara Chemical Co., Ltd.) and the Picolite series A115, S115, etc. (manufactured by Hercules Co., Ltd.).

[0029] A representative example of the terpene-aromatic compound resin is terpene-phenol resin. The terpene-phenol resin can be obtained by reacting terpenes with various phenols using a Friedel-Crafts catalyst, or by further condensing with formalin. There is no particular limitation on the terpene as the raw material, and monoterpene hydrocarbons such as α-pinene and limonene are preferred, and those containing α-pinene are more preferred. Commercially available terpene-aromatic compound resins can be used, and examples of such resins include YS Polystar U series, YS Polystar T series, YS Polystar S series, YS Polystar G series, YS Polystar N series, YS Polystar K series, and YS Polystar TH series (manufactured by Yasuhara Chemical Co., Ltd.), Tamanol 803L, and Tamanol 901 (manufactured by Arakawa Chemical Industries Co., Ltd.).

[0030] Rosin resins are the residues remaining after collecting balsams such as pine resin (pine tar), which is the sap of plants of the Pinaceae family, and distilling turpentine essential oil. Examples of rosin resins include natural resins mainly composed of rosin acid (abietic acid, palustric acid, isopimaric acid, etc.), and modified resins and hydrogenated resins obtained by modifying, hydrogenating, etc., of these. Specific examples include natural resin rosin, polymerized rosin and partially hydrogenated rosin thereof; glycerin ester rosin, partially hydrogenated rosin, fully hydrogenated rosin and polymerized rosin thereof; pentaerythritol ester rosin, partially hydrogenated rosin and polymerized rosin thereof; and the like. Examples of natural resin rosins include gum rosin, tall oil rosin, wood rosin, etc., contained in raw rosin and tall oil. Rosin-based resins can be commercially available products, such as Polypale and Pentalin C (manufactured by Eastman Chemical Co.), Lime Resin No. 1, Pencel A and Pencel AD (manufactured by Arakawa Chemical Industries Co., Ltd.), Neotoll 105 (manufactured by Harima Chemical Co., Ltd.), SN Tack 754 (manufactured by San Nopco Co., Ltd.), and Hi-Rosin S (manufactured by Taisha Matsu Oil Co., Ltd.).

[0031] Examples of dicyclopentadiene resins include resins obtained by polymerizing dicyclopentadiene using Friedel-Crafts catalysts such as AlCl3 and BF3. Commercially available dicyclopentadiene resins include Marcaretz M-890A (manufactured by Maruzen Petrochemical Co., Ltd.), Quinton 1920, and Quinton 1105 (manufactured by Zeon Corporation).

[0032] Examples of the alkylphenol resin include those obtained by condensation reaction of alkylphenol and formaldehyde under a catalyst. Commercially available alkylphenol resins include Tackirol 201 (alkylphenol formaldehyde resin, manufactured by Taoka Chemical Industry Co., Ltd.), Tackirol 250-I (brominated alkylphenol formaldehyde resin, manufactured by Taoka Chemical Industry Co., Ltd.), Tackirol 250-III (brominated alkylphenol formaldehyde resin, manufactured by Taoka Chemical Industry Co., Ltd.), Hitanol 1502P (alkylphenol formaldehyde resin, manufactured by Hitachi Chemical Co., Ltd.), R7521P, SP1068, R7510PJ, R7572P and R7578P (manufactured by SI GROUP INC.).

[0033] Examples of the resin having a softening point of 160° C. or less include coumarone-indene resin, α-methylstyrene resin, terpene resin, and alkylphenol resin.

[0034] The softening point of the resin (the resin constituting the skeleton of the modified resin) is preferably 20° C. or higher, more preferably 25° C. or higher, even more preferably 40° C. or higher, and particularly preferably 70° C. or higher. The softening point is 160° C. or lower, more preferably 150° C. or lower, and even more preferably 130° C. or lower. In this specification, the softening point is the temperature at which the ball drops when the softening point specified in JIS K 6220-1:2001 is measured using a ring and ball softening point tester.

[0035] In at least one modified polymer selected from the group consisting of modified resins having a functional group that has affinity for silica and modified thermoplastic elastomers having a functional group that has affinity for silica, the thermoplastic elastomer that constitutes the skeleton of the modified thermoplastic elastomer having a functional group that has affinity for silica is not particularly limited, and any known thermoplastic elastomer can be used.

[0036] Examples of the thermoplastic elastomer include olefin-based thermoplastic elastomers, styrene-based thermoplastic elastomers, vinyl chloride-based thermoplastic elastomers, urethane-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, polyester-based thermoplastic elastomers, and fluorine-based thermoplastic elastomers. These may be used alone or in combination of two or more. Among them, styrene-based thermoplastic elastomers are preferred from the viewpoint of overall performance such as abrasion resistance, rubber strength, wet grip performance, high-speed wet grip performance, and low fuel consumption.

[0037] The thermoplastic elastomer constituting the skeleton of the modified thermoplastic elastomer preferably has a block made of an aromatic vinyl monomer from the viewpoint of overall performance such as abrasion resistance, rubber strength, wet grip performance, high-speed wet grip performance, and fuel economy. Examples of aromatic vinyl monomers include styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, and divinylnaphthalene. These may be used alone or in combination of two or more. Among them, styrene is preferred.

[0038] The styrene-based thermoplastic elastomer may have at least one hard segment containing a styrene-based unit and at least one soft segment. The hard segment may be a thermoplastic polymer block, and the soft segment may be an elastomeric polymer block. The hard and soft segments may be arranged in a linear, star, or branched configuration.

[0039] In the styrene-based thermoplastic elastomer, the styrene-based hard segment preferably has a glass transition temperature (Tg) of not less than 80° C. For example, the styrene-based hard segment is preferably polystyrene.

[0040] The styrenic hard segment may be a homopolymer of a styrene monomer, a block or random copolymer of several styrene monomers; a copolymer of one or more styrene monomers and one or more non-styrene monomers (such as 1,3-dienes); or the like.

[0041] The styrene monomer in this specification may be either styrene or a substituted styrene. Examples of substituted styrene include methylstyrene (o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, α,2-dimethylstyrene, α,4-dimethylstyrene, diphenylethylene, etc.), para-(tert-butyl)styrene, chlorostyrene (o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene, 2,4,6-trichlorostyrene, etc.), bromostyrene (o-bromostyrene, m-bromostyrene, p-bromostyrene, 2,4-dibromostyrene, 2,6-dibromostyrene, 2,4,6-tribromostyrene, etc.), fluorostyrene (o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, 2,4-difluorostyrene, 2,6-difluorostyrene, 2,4,6-trifluorostyrene, etc.), and para-hydroxystyrene.

[0042] In the styrene-based thermoplastic elastomer, the content of the conjugated diene unit (also referred to as the conjugated diene monomer unit) in 100% by mass of the styrene-based thermoplastic elastomer is preferably 20% by mass or more, more preferably 25% by mass or more, and even more preferably 30% by mass or more. The upper limit of the content is preferably 98% by mass or less, more preferably 95% by mass or less, and even more preferably 93% by mass or less. The conjugated diene unit contains at least one diene-based soft segment which may be totally or partially hydrogenated.

[0043] The diene-based segments include homopolymers of conjugated dienes, block or random copolymers of several conjugated dienes; copolymers of one or more conjugated dienes with one or more other non-diene monomers, such as styrene monomers; and the like.

[0044] The content of the conjugated diene units constituting the diene soft segment is preferably 50 mass% or more, more preferably 60 mass% or more, even more preferably 70 mass% or more, and particularly preferably 80 mass% or more, based on 100 mass of the diene soft segment.

[0045] The conjugated diene unit may be a 1,3-butadiene unit, an isoprene unit, etc. Thus, the diene-based segment may be a polybutadiene, a polyisoprene, a copolymer of 1,3-butadiene and isoprene, etc. The copolymer of 1,3-butadiene and isoprene may be either a block or random copolymer.

[0046] The styrene-based thermoplastic elastomer may be, for example, a diblock consisting of a single diene-based soft segment and a single styrene-based hard segment. Examples of the diblock consisting of a single diene-based soft segment and a single styrene-based hard segment include a styrene / butadiene (SB) block copolymer, a styrene / isoprene (SI) block copolymer, a styrene / butadiene / isoprene (SBI) block copolymer, and a mixture of these copolymers. The block of the diene-based soft segment may be either a random copolymer or a block copolymer.

[0047] A suitable example of the styrene-based thermoplastic elastomer is a styrene-based thermoplastic elastomer having two or more styrene-based hard segments. When the styrene-based thermoplastic elastomer has two or more styrene-based hard segments, for example, the styrene-based thermoplastic elastomer has at least two chain ends each having a styrene-based hard segment, and the styrene-based hard segment is bonded via one or more diene-based soft segments. Among them, the styrene-based thermoplastic elastomer is preferably a triblock having two or more styrene-based hard segments. In this case, the triblock is composed of two styrene-based hard segments and one diene-based soft segment.

[0048] Examples of the triblock consisting of two styrene-based hard segments and one diene-based soft segment include styrene / butadiene / styrene (SBS) block copolymer, styrene / isoprene / styrene (SIS) block copolymer, styrene / butadiene / isoprene / styrene (SBIS) block copolymer, and mixtures of these copolymers. The diene-based soft segment block may be either a random copolymer or a block copolymer. Among them, SIS block copolymer, SBIS block copolymer, and mixtures of these copolymers are preferred, and SIS block copolymer is more preferred.

[0049] The styrene-based thermoplastic elastomer may be one in which the conjugated diene units of the diene-based soft segment are partially hydrogenated, or one in which all of the conjugated diene units are hydrogenated. Also, the styrene-based thermoplastic elastomer in which some of the double bonds of the conjugated diene units of the diene-based soft segment are reduced to single bonds by a method other than hydrogenation can be used equally well. Methods for reducing the double bonds of the conjugated diene units to single bonds include reduction with aluminum hydride and diimine.

[0050] When a part or all of the conjugated diene units of the diene soft segment in the styrene-based thermoplastic elastomer are hydrogenated, examples of the hydrogenated diblock composed of the single diene soft segment and the single styrene hard segment include styrene / ethylene / butylene (SEB) block copolymer, styrene / ethylene / propylene (SEP) block copolymer, styrene / ethylene / ethylene / propylene (SEEP) block copolymer, and mixtures of these copolymers. The block of the diene soft segment (hydrogenated) may be either a random copolymer or a block copolymer.

[0051] When a part or all of the conjugated diene units of the diene soft segment in the styrene-based thermoplastic elastomer are hydrogenated, examples of the hydrogenated triblock consisting of two styrene hard segments and one diene soft segment include styrene / ethylene / butylene / styrene (SEBS) block copolymer, styrene / ethylene / propylene / styrene (SEPS) block copolymer, styrene / ethylene / ethylene / propylene / styrene (SEEPS) block copolymer, and mixtures of these copolymers. The block of the diene soft segment (hydrogenated) may be either a random copolymer or a block copolymer.

[0052] The number average molecular weight (Mn) of the styrene-based thermoplastic elastomer is preferably 50,000 or more, more preferably 60,000 or more, even more preferably 80,000 or more, and particularly preferably 100,000 or more. The upper limit is preferably 500,000 or less, more preferably 450,000 or less, even more preferably 300,000 or less, and particularly preferably 250,000 or less. Within the above range, the effect tends to be better obtained. In this specification, the Mn of various polymers can be determined in terms of standard polystyrene based on the measured value obtained by gel permeation chromatography (GPC) (GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: TSKGEL SUPERMULTIPORE HZ-M manufactured by Tosoh Corporation).

[0053] In the modified resin and modified thermoplastic elastomer having a functional group having an affinity with silica, the functional group having an affinity with silica may be any group having an affinity with silica. A suitable example of the functional group having an affinity with silica is a functional group containing at least one element selected from the group consisting of oxygen, silicon, sulfur, and nitrogen.

[0054] Specific examples of functional groups having affinity with silica include a group represented by SiOR (R is a hydrogen atom or a hydrocarbon group), an amino group, an amide group, a silyl group, an alkoxysilyl group, an isocyanate group, an imino group, an imidazole group, a urea group, an ether group, a carbonyl group, an oxycarbonyl group, a mercapto group, a sulfide group, a disulfide group, a sulfonyl group, a sulfinyl group, a thiocarbonyl group, an ammonium group, an imide group, a hydrazo group, an azo group, a diazo group, a carboxyl group, a nitrile group, a pyridyl group, an alkoxy group, a hydroxyl group, an oxy group, and an epoxy group. The functional group may have a substituent. The functional group may be one type or two or more types.

[0055] Of these, from the viewpoint of overall performance such as abrasion resistance, rubber strength, wet grip performance, high-speed wet grip performance, and fuel economy, groups represented by SiOR (R is a hydrogen atom or a hydrocarbon group), which may have a substituent, alkoxysilyl groups, amino groups, hydroxyl groups, epoxy groups, and carboxyl groups are preferred.

[0056] The group represented by SiOR includes SiOH and SiOR (R is a hydrocarbon group). The hydrocarbon group of R preferably has 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 to 4 carbon atoms. The hydrocarbon group may be linear, branched, or cyclic. Examples of the hydrocarbon group of R include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, pentyl, and hexyl groups.

[0057] The alkoxysilyl group is -Si(OR 1 ) k (R 2 ) 3-k A group represented by R 1 ~R 2 represents hydrogen or a hydrocarbon group and may be the same or different. k represents an integer of 1, 2 or 3. 1 ~R 2 The number of carbon atoms in the hydrocarbon group is preferably 1 to 12, more preferably 1 to 8, and still more preferably 1 to 4. Specific examples of the unsubstituted or substituted alkoxysilyl group include monoalkoxysilyl groups (monomethoxysilyl group, monoethoxysilyl group, monopropoxysilyl group, monobutoxysilyl group, etc.), dialkoxysilyl groups (dimethoxysilyl group, diethoxysilyl group, dipropoxysilyl group, dibutoxysilyl group, etc.), trialkoxysilyl groups (trimethoxysilyl group, triethoxysilyl group, tripropoxysilyl group, tributoxysilyl group, etc.), methyldimethoxysilyl group, methyldiethoxysilyl group, dimethylethoxysilyl group, aminoalkoxysilyl group, etc.

[0058] The amino group includes primary amino groups (-NH2), secondary amino groups (-NHR11 ), tertiary amino group (-NR 12 R 13 ), where R 11 ~R 13 R is any organic group, which may be linked to form a ring. As described above, the amino group may have a substituent. 11 ~R 13 The number of carbon atoms is preferably 1 to 12, more preferably 1 to 6, and further preferably 1 to 4. Specific examples of the unsubstituted or substituted amino group include mono-C groups such as a primary amino group (-NH2), an amino group, and an alkylamino group (a methylamino group, an ethylamino group, a propylamino group, an isopropylamino group, and a butylamino group). 1-4 alkylamino group), dialkylamino group (dimethylamino group, diethylamino group, dipropylamino group, diisopropylamino group, dibutylamino group, methylethylamino group, etc.) 1-4 alkylamino group), alkoxycarbonylamino group (e.g., methoxycarbonylamino group, isoproxycarbonylamino group, tert-butoxycarbonylamino group, etc. 1-6 alkoxycarbonylamino groups, and the like.

[0059] As the functional group, any compound capable of introducing the functional group can be used, and examples thereof include compounds represented by the following formula:

[0060] [ka] (In the formula, R 1 , R 2 and R 3 R may be the same or different and represents an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group (-COOH), a mercapto group (-SH), or a derivative thereof. 4 and R 5 R may be the same or different and represents a hydrogen atom or an alkyl group. 4 and R 5 may be bonded to form a ring structure together with the nitrogen atom, and n represents an integer.

[0061] R 1 , R 2 and R 3 R is preferably an alkoxy group (preferably an alkoxy group having 1 to 8 carbon atoms, more preferably an alkoxy group having 1 to 4 carbon atoms). 4 and R 5 is preferably an alkyl group (preferably an alkyl group having 1 to 3 carbon atoms). n is preferably 1 to 5, more preferably 2 to 4, and further preferably 3. In addition, R 4 and R 5 When the nitrogen atom and the nitrogen atom are bonded to each other to form a ring structure, the ring is preferably a 4- to 8-membered ring. The alkoxy group also includes a cycloalkoxy group (such as a cyclohexyloxy group) and an aryloxy group (such as a phenoxy group and a benzyloxy group).

[0062] Specific examples of the compound represented by the formula include 2-dimethylaminoethyl trimethoxysilane, 3-dimethylaminopropyl trimethoxysilane, 2-dimethylaminoethyl triethoxysilane, 3-dimethylaminopropyl triethoxysilane, 2-diethylaminoethyl trimethoxysilane, 3-diethylaminopropyl trimethoxysilane, 2-diethylaminoethyl triethoxysilane, 3-diethylaminopropyl triethoxysilane, etc. Among them, 3-dimethylaminopropyl trimethoxysilane, 3-dimethylaminopropyl triethoxysilane, and 3-diethylaminopropyl trimethoxysilane are preferred. These may be used alone or in combination of two or more.

[0063] Other compounds to which the functional group can be introduced include the following compounds. Ethylenically unsaturated silane compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, dimethoxymethylvinylsilane, diethoxymethylvinylsilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-acryloxypropyltrimethoxysilane;

[0064] Polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolethane triglycidyl ether, and trimethylolpropane triglycidyl ether; polyglycidyl ethers of aromatic compounds having two or more phenol groups such as diglycidylated bisphenol A; polyepoxy compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, and polyepoxidized liquid polybutadiene; 4,4'-diglycidyl -diphenylmethylamine, 4,4'-diglycidyl-dibenzylmethylamine, and other epoxy group-containing tertiary amines; diglycidylamino compounds such as diglycidylaniline, N,N'-diglycidyl-4-glycidyloxyaniline, diglycidylorthotoluidine, tetraglycidylmetaxylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, and tetraglycidyl-1,3-bisaminomethylcyclohexane;

[0065] Amino group-containing acid chlorides such as bis-(1-methylpropyl)carbamic acid chloride, 4-morpholinecarbonyl chloride, 1-pyrrolidinecarbonyl chloride, N,N-dimethylcarbamic acid chloride, and N,N-diethylcarbamic acid chloride; epoxy group-containing silane compounds such as 1,3-bis-(glycidyloxypropyl)-tetramethyldisiloxane and (3-glycidyloxypropyl)-pentamethyldisiloxane;

[0066] Sulfide group-containing silane compounds such as (trimethylsilyl)[3-(trimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(triethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tripropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tributoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldiethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldipropoxysilyl)propyl]sulfide, and (trimethylsilyl)[3-(methyldibutoxysilyl)propyl]sulfide;

[0067] N-substituted aziridine compounds such as ethyleneimine and propyleneimine; alkoxysilanes such as methyltriethoxysilane; (thio)benzophenone compounds having amino groups and / or substituted amino groups such as 4-N,N-dimethylaminobenzophenone, 4-N,N-di-t-butylaminobenzophenone, 4-N,N-diphenylaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(diphenylamino)benzophenone, and N,N,N',N'-bis-(tetraethylamino)benzophenone; 4-N,N-dimethylaminobenzaldehyde, 4-N,N-diphenylaminobenzaldehyde, 4- benzaldehyde compounds having an amino group and / or a substituted amino group, such as N,N-divinylaminobenzaldehyde; N-substituted pyrrolidones, such as N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, Nt-butyl-2-pyrrolidone, and N-methyl-5-methyl-2-pyrrolidone; N-substituted piperidones, such as N-methyl-2-piperidone, N-vinyl-2-piperidone, and N-phenyl-2-piperidone; N-substituted lactams, such as N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, N-methyl-ω-laurylolactam, N-vinyl-ω-laurylolactam, N-methyl-β-propiolactam, and N-phenyl-β-propiolactam;

[0068] N,N-Bis-(2,3-epoxypropoxy)-aniline, 4,4-methylene-bis-(N,N-glycidylaniline), tris-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6-triones, N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethylethyleneurea, 1,3-divinylethyleneurea, 1,3-diethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 4-N,N-dimethylaminoacetophene, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-propanone, 1,7-bis(methylethylamino)-4-heptanone;

[0069] Ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,2-cyclohexanediamine, N-methylethylenediamine, N-methylpropanediamine, N,N-dimethylethylenediamine, N,N-dimethylpropanediamine, N-acetylethylenediamine, isophoronediamine;

[0070] 4-N,N-dimethylaminoethylstyrene, 3-N,N-dimethylaminoethylstyrene, 4-N,N-diethylaminoethylstyrene, 3-N,N-diethylaminoethylstyrene, 4-N,N-di-n-propylaminoethylstyrene, 3-N,N-di-n-propylaminoethylstyrene, 4-N,N-di-n-butylaminoethylstyrene, 3-N,N-di-n-butylaminoethylstyrene, 4-N,N-diallylaminoethylstyrene, 3-N,N-diallylaminoethylstyrene, 4-N,N-bis(trimethylsilyl)aminoethylstyrene, 3-N,N-bis(trimethylsilyl)aminoethylstyrene, 4-N,N-bis(tert-butyldimethylsilyl)aminoethylstyrene, 3-N,N-bis(tert-butyldimethylsilyl)aminoethylstyrene, 4-aziridinylethylstyrene, 3-aziridinylethylstyrene, 4-pyrrolidinylethylstyrene, 3-pyrrolidinylethylstyrene, 4-piperidinylethylstyrene, 3-piperidinylethylstyrene, 4-hexamethyleneiminoethylstyrene, 3-hexamethyleneiminoethylstyrene;

[0071] The modified resin and modified thermoplastic elastomer having the functional group having affinity with silica can be produced by a known method. For example, the method of imparting the functional group having affinity with silica to the resin or thermoplastic elastomer constituting the skeleton includes, but is not limited to, a method of copolymerizing a monomer having the functional group during polymerization of the resin or thermoplastic elastomer to introduce the functional group into the terminal and / or main chain, a method of adding a compound having the functional group to a resin or thermoplastic elastomer after polymerization or a resin or thermoplastic elastomer that is commercially available to introduce the functional group, and the like.

[0072] Specifically, the following methods can be mentioned, but the method is not limited to these. (1) The compound having the functional group has an unsaturated bond and is added ionically and / or radically to the resin or thermoplastic elastomer. (2) A radical generator such as a peroxide compound is allowed to react with the compound having the functional group to add it to the resin or thermoplastic elastomer. (3) The resin or thermoplastic elastomer has a functional group such as a carboxyl group or a hydroxyl group, and is further reacted with a compound having the functional group to introduce the desired functional group into the resin or thermoplastic elastomer. (4) When polymerizing the resin and thermoplastic elastomer, a monomer having the functional group is copolymerized.

[0073] (Rubber component A that constitutes modified polymer-extended rubber) The rubber component A constituting the modified polymer-extended rubber preferably has a number average molecular weight of 50,000 or more, more preferably 100,000 or more, even more preferably 150,000 or more, and particularly preferably 200,000 or more. The upper limit is preferably 3,000,000 or less, more preferably 2,000,000 or less. Within the above range, the effect tends to be better obtained.

[0074] The rubber component A constituting the modified polymer-extended rubber preferably has a glass transition temperature (Tg) of −10° C. or lower, more preferably −20° C. or lower, even more preferably −40° C. or lower, particularly preferably −45° C. or lower, and may also be −50° C. or lower or −55° C. or lower. There is no particular lower limit, but it is preferably −130° C. or higher, more preferably −120° C. or higher.

[0075] The rubber component A constituting the modified polymer extended rubber may be either unmodified rubber or modified rubber, but modified rubber is preferred from the viewpoint of overall performance such as abrasion resistance, rubber strength, wet grip performance, high-speed wet grip performance and fuel economy.

[0076] The mechanism by which the above-mentioned effects are obtained is not clear, but is presumed to be as follows. The rubber component A that constitutes the modified polymer-extended rubber and the modified polymer have functional groups, which strongly interact with the silica, improving fuel efficiency, abrasion resistance, and rubber strength. It is therefore presumed that this will result in improved overall performance in terms of abrasion resistance, rubber strength, wet grip performance, high-speed wet grip performance, and fuel efficiency. Furthermore, since the modified rubber and the modified polymer each have a functional group and are uniformly mixed in advance, they are bound by a strong interaction, which prevents the modified polymer from bleeding, making it possible to provide a rubber in which changes over time are significantly suppressed.

[0077] The modified rubber may be a rubber having a functional group that interacts with a filler such as silica. For example, it may be a terminal modified rubber (terminal modified rubber having a functional group at the terminal) in which at least one terminal of the rubber is modified with a compound (modifier) ​​having a functional group, a main chain modified rubber having a functional group in the main chain, a main chain terminal modified rubber having functional groups in the main chain and at least one terminal (for example, a main chain terminal modified rubber having a functional group in the main chain and at least one terminal modified with a modifier), or a terminal modified rubber modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule and having a hydroxyl group or an epoxy group introduced therein.

[0078] The functional group in the modified rubber may be, for example, the functional group having affinity with silica. Among them, from the viewpoint of overall performance such as abrasion resistance, rubber strength, wet grip performance, high-speed wet grip performance and fuel economy, the group represented by SiOR (R is hydrogen atom or hydrocarbon group), alkoxysilyl group, amino group, hydroxyl group, epoxy group, and carboxyl group, which may have the above-mentioned substituent, are preferred. In addition, the compound capable of introducing the functional group may be, for example, the above-mentioned compound.

[0079] As the rubber component A constituting the modified polymer extended rubber, for example, a diene rubber can be used. Examples of the diene rubber include isoprene rubber, butadiene rubber (BR), styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), ethylene propylene diene rubber (EPDM), chloroprene rubber (CR), and acrylonitrile butadiene rubber (NBR). Examples of the diene rubber include butyl rubber and fluororubber. Among them, from the viewpoint of the overall performance of abrasion resistance, rubber strength, wet grip performance, high-speed wet grip performance, and low fuel consumption, SBR, BR, and isoprene rubber are preferred, and SBR and BR are more preferred. As mentioned above, the diene rubber may be a non-modified diene rubber or a modified diene rubber. It may also be a hydrogenated product.

[0080] The SBR is not particularly limited, and for example, emulsion polymerized styrene butadiene rubber (E-SBR), solution polymerized styrene butadiene rubber (S-SBR), etc. can be used. These may be used alone or in combination of two or more kinds.

[0081] The styrene content of SBR is preferably 3% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more. The styrene content is preferably 60% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, and particularly preferably 25% by mass or less. Within the above range, the effect tends to be better obtained. In this specification, the styrene content of SBR is 1 It is calculated by H-NMR measurement.

[0082] The vinyl content of the SBR is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 12% by mass or more. The vinyl content is preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less. When it is within the above range, the effect tends to be better. The vinyl content (amount of 1,2-bonded butadiene units) can be measured by infrared absorption spectroscopy.

[0083] As the SBR, for example, SBR manufactured and sold by Sumitomo Chemical Co., Ltd., JSR Corporation, Asahi Kasei Corporation, Nippon Zeon Co., Ltd., and the like can be used.

[0084] The SBR may be unmodified or modified. The modified SBR may be modified SBR into which the same functional group as that of the modified diene rubber is introduced. The SBR may also be hydrogenated.

[0085] The BR is not particularly limited, and for example, high cis BR with a high cis content, BR containing syndiotactic polybutadiene crystals, BR synthesized using a rare earth catalyst (rare earth BR), etc. can be used. These may be used alone or in combination of two or more. Among them, high cis BR with a cis content of 90% by mass or more is preferred because it improves wear resistance.

[0086] The BR may be unmodified or modified. The modified BR may be a modified BR having the same functional group as the modified diene rubber. The BR may be a hydrogenated product.

[0087] As the BR, for example, products from Ube Industries, Ltd., JSR Corporation, Asahi Kasei Corporation, Zeon Corporation, etc. can be used.

[0088] Examples of isoprene-based rubber include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR. Examples of NR include SIR20, RSS♯3, TSR20, and other rubber industry-standard rubbers. Examples of IR include IR2200 and other rubber industry-standard rubbers. Examples of modified NR include deproteinized natural rubber (DPNR), high-purity natural rubber (UPNR), and other rubbers. Examples of modified NR include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Examples of modified IR include epoxidized isoprene rubber, hydrogenated isoprene rubber, and grafted isoprene rubber. These may be used alone or in combination of two or more.

[0089] The modified polymer-extended rubber can be produced by thoroughly mixing the rubber component A with the modified resin having a functional group with affinity for silica and the modified thermoplastic elastomer. For example, the modified polymer-extended rubber can be obtained by mixing the rubber component A in a solution state in an organic solvent with the modified resin and / or modified thermoplastic elastomer adjusted to a liquid state, and, if necessary, recovering the modified polymer-extended rubber by a known method.

[0090] As the organic solvent, any solvent compatible with the monomer of the rubber component A, the rubber component A, the modified resin and / or the modified thermoplastic elastomer can be used. Suitable organic solvents are aliphatic and alicyclic, and specific examples thereof include n-pentane, isopentane, isoamylene (2-methyl-2-butene, 2-methyl-1-butene and 3-methyl-1-butene), 2,2-dimethylbutane, 2,2-dimethylpropane (neopentane), n-heptane, n-octane, isooctane, cyclopentane, cyclohexane, n-hexane, methylcyclopentane and methylcyclohexane, and mixtures of these compounds. Other organic solvents include aromatic hydrocarbons (benzene, toluene, etc.).

[0091] The modified resin and / or modified thermoplastic elastomer adjusted to the liquid state may be, for example, one that is in a solid state at room temperature and is subjected to a process to transition to a liquid state. Specifically, the modified resin and / or modified thermoplastic elastomer adjusted to a liquid state may be heated to a temperature exceeding its softening point by a known technique.

[0092] In particular, the modified polymer-extended rubber is preferably produced by preparing the rubber component A by polymerization in an organic solvent, and adding a solution of the modified resin and / or the modified thermoplastic elastomer to the solution after polymerization. In this case, the modified polymer-extended rubber in which the rubber component A and the modified polymer are sufficiently mixed is preferably obtained. The methods of polymerization in an organic solvent, preparation of the solution of the modified resin and / or the modified thermoplastic elastomer, and addition of the solution of the modified resin and / or the modified thermoplastic elastomer are not particularly limited, and known methods may be used as appropriate.

[0093] In the modified polymer-extended rubber, the total amount of the modified resin and modified thermoplastic elastomer per 100 parts by mass of the rubber component A is preferably 5 parts by mass or more, more preferably 30 parts by mass or more, and even more preferably 40 parts by mass or more. The upper limit of the total amount is preferably 100 parts by mass or less, more preferably 70 parts by mass or less, and even more preferably 60 parts by mass or less. Within the above range, the effect tends to be better obtained.

[0094] (All rubber components constituting the rubber composition) The total rubber components contained in the rubber composition are composed of rubber component A constituting the modified polymer-extended rubber, and rubber component B, which is included as necessary other than rubber component A. For example, in the case of a rubber composition consisting of modified SBR and a modified polymer-extended rubber, unmodified BR, and a filler, the total rubber components contained in the rubber composition are modified SBR (corresponding to rubber component A) and unmodified BR (corresponding to rubber component B). Here, rubber component B can be any rubber known in the rubber field, and examples thereof include unmodified rubber and modified rubber similar to the above-mentioned rubber component A constituting the modified polymer-extended rubber.

[0095] In this specification, the modified thermoplastic elastomer and the thermoplastic elastomer are not included in the total rubber components constituting the rubber composition.

[0096] The content of SBR (the total amount of SBR constituting the modified polymer-extended rubber and other SBRs contained other than the SBR) in 100% by mass of all rubber components contained in the rubber composition (100% by mass of the total amount of the rubber components A and B) is preferably 20% by mass or more, more preferably 25% by mass or more. There is no particular lower limit, but it may be 5% by mass or more or 10% by mass or more. Within the above range, the effect tends to be better obtained.

[0097] In 100% by mass of all rubber components contained in the rubber composition, the content of BR (the total amount of BR constituting the modified polymer-extended rubber and other BRs contained other than the BR) is preferably 20% by mass or more, more preferably 25% by mass or more. The lower limit is not particularly limited, but may be 5% by mass or more or 10% by mass or more. Within the above range, the effect tends to be better obtained.

[0098] In 100% by mass of all rubber components contained in the rubber composition, the content of isoprene-based rubber (the total amount of isoprene-based rubber constituting the modified polymer-extended rubber and other isoprene-based rubbers contained other than the isoprene-based rubber) is preferably 60% by mass or less, more preferably 50% by mass or less. There is no particular lower limit, but it may be 3% by mass or more, or 5% by mass or more. Within the above range, the effect tends to be better obtained.

[0099] The content of the rubber component A in the modified polymer-extended rubber is preferably 20% by mass or more, more preferably 40% by mass or more, based on 100% by mass of all rubber components in the rubber composition. When the content is within the above range, the effect tends to be better.

[0100] (Modified polymer constituting rubber composition) The rubber composition contains the modified polymer (the modified resin, the modified thermoplastic elastomer), and the modified polymer constituting the rubber composition means all of the modified polymers contained in the composition. For example, in the case of a rubber composition comprising a modified polymer-extended rubber made of modified SBR and the modified resin, the modified resin, and a filler, the modified polymer contained in the rubber composition is the modified resin constituting the modified polymer-extended rubber and the modified resin added separately.

[0101] In the rubber composition, the total amount of the modified resin and modified thermoplastic elastomer is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, even more preferably 30 parts by mass or more, and particularly preferably 40 parts by mass or more, based on 100 parts by mass of the total rubber components contained in the rubber composition (100 parts by mass of the total amount of the rubber components A and B). The upper limit is preferably 120 parts by mass or less, more preferably 100 parts by mass or less, even more preferably 90 parts by mass or less, and particularly preferably 80 parts by mass or less. Within the above range, the effect tends to be better obtained. The content of the modified resin and the content of the modified thermoplastic elastomer based on 100 parts by mass of the total rubber components are also preferably in the same range.

[0102] The total content of the modified resin and modified thermoplastic elastomer contained in the modified polymer-extended rubber is preferably 20% by mass or more, more preferably 25% by mass or more, and even more preferably 50% by mass or more, based on 100% by mass of the total amount of the modified resin and modified thermoplastic elastomer contained in the rubber composition. When it is within the above range, the effect tends to be better.

[0103] (Filler) The rubber composition preferably contains a filler. As the filler, inorganic fillers such as silica, carbon black, calcium carbonate, talc, alumina, clay, aluminum hydroxide, aluminum oxide, and mica; poorly dispersible fillers; and other fillers known in the rubber field can be used. Among them, silica and carbon black are preferred, and silica is more preferred.

[0104] In the rubber composition, the total amount of the filler is preferably 50 parts by mass or more, more preferably 85 parts by mass or more, even more preferably 105 parts by mass or more, and particularly preferably 125 parts by mass or more, based on 100 parts by mass of all rubber components contained in the rubber composition. The upper limit is preferably 200 parts by mass or less, more preferably 175 parts by mass or less, even more preferably 155 parts by mass or less, and particularly preferably 135 parts by mass or less. Within the above range, the effect tends to be better obtained.

[0105] Examples of silica that can be used include dry process silica (anhydrous silica) and wet process silica (hydrated silica). Among them, wet process silica is preferred because it has a large number of silanol groups. Examples of silica that can be used include products from Degussa, Rhodia, Tosoh Silica, Solvay Japan, and Tokuyama.

[0106] The nitrogen adsorption specific surface area (N2SA) of the silica is preferably 70 m 2 / g or more, more preferably 140m 2 / g or more, more preferably 160m 2 / g or more, particularly preferably 180m 2 The upper limit of the N2SA of silica is not particularly limited, but is preferably 300 m 2 / g or less, more preferably 275m 2 / g or less, more preferably 250m 2 Within the above range, there is a tendency for the effect to be better obtained. In this specification, the N2SA of silica is a value measured by the BET method in accordance with ASTM D3037-93.

[0107] In the rubber composition, the content of silica is preferably 30 parts by mass or more, more preferably 80 parts by mass or more, even more preferably 100 parts by mass or more, and particularly preferably 120 parts by mass or more, based on 100 parts by mass of the total rubber components contained in the rubber composition. The upper limit is preferably 200 parts by mass or less, more preferably 170 parts by mass or less, even more preferably 150 parts by mass or less, and particularly preferably 130 parts by mass or less. Within the above range, the effect tends to be better obtained.

[0108] When silica is contained, a silane coupling agent may be blended together with the silica. Usable silane coupling agents include any silane coupling agents that have been conventionally used in combination with silica in the rubber industry, and are not particularly limited. Examples of such silane coupling agents include bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylethyl)trisulfide, bis(4-trimethoxysilylbutyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)disulfide, bis(4-triethoxysilylbutyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, bis(2-trimethoxysilylethyl)disulfide, bis(4-trimethoxy ...4-trimethoxysilylbutyl)disulfide, bis Examples of the silylsilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide and other sulfide-based silylsilylsilanes; mercapto-based silylsilanes such as 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, and Momentive's NXT and NXT-Z; vinyl-based silylsilanes such as vinyltriethoxysilane and vinyltrimethoxysilane; amino-based silylsilanes such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane; glycidoxy-based silylsilanes such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro-based silylsilanes such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chloro-based silylsilanes such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. Commercially available products include those from Degussa, Momentive, Shin-Etsu Silicone, Tokyo Chemical Industry, Azumax, and Dow Corning Toray. These may be used alone or in combination of two or more. Of these, sulfide-based and mercapto-based products are preferred.

[0109] In the rubber composition, the content of the silane coupling agent is preferably 3 parts by mass or more, more preferably 6 parts by mass or more, based on 100 parts by mass of silica. The content is preferably 20 parts by mass or less, more preferably 15 parts by mass or less. When the content is within the above range, the effect tends to be better.

[0110] Examples of carbon black that can be used include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. These may be used alone or in combination of two or more. Commercially available products include those from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Co., Ltd., Lion Co., Ltd., Shin-Nichika Carbon Co., Ltd., Columbia Carbon Co., Ltd., and the like.

[0111] The nitrogen adsorption specific surface area (N2SA) of carbon black is 50m 2 / g or more is preferable, and 80m 2 / g or more is more preferable, and 100m 2 / g or more is more preferable. 2 / g or less is preferable, and 150m 2 / g or less is more preferable, and 130m 2 Within the above range, there is a tendency that the effect is better obtained. In this specification, the nitrogen adsorption specific surface area of ​​carbon black is determined in accordance with JIS K6217-2:2001.

[0112] In the rubber composition, the content of carbon black is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, based on 100 parts by mass of the total rubber components contained in the rubber composition. The upper limit 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. Within the above range, the effect tends to be better obtained.

[0113] (Plasticizer) The rubber composition may contain other plasticizers in addition to the modified polymer (the modified resin, the modified thermoplastic elastomer) constituting the modified polymer-extended rubber. Here, the plasticizer is a material that imparts plasticity to the rubber component, and examples thereof include liquid plasticizers (plasticizers in a liquid state at room temperature (25°C)) and resins (resins in a solid state at room temperature (25°C)). The rubber composition contains the modified polymer (the modified resin, the modified thermoplastic elastomer), and the plasticizers constituting the rubber composition refer to all plasticizers contained in the composition. For example, in the case of a rubber composition consisting of a modified polymer-extended rubber made of modified SBR and the modified resin, oil, the thermoplastic elastomer, and a filler, the plasticizers contained in the rubber composition are the modified resin, oil, and thermoplastic elastomer constituting the modified polymer-extended rubber.

[0114] In the rubber composition, the total amount of the plasticizer is preferably 20 parts by mass or more, more preferably 35 parts by mass or more, even more preferably 45 parts by mass or more, and particularly preferably 55 parts by mass or more, based on 100 parts by mass of all rubber components contained in the rubber composition. The upper limit is preferably 120 parts by mass or less, more preferably 100 parts by mass or less, even more preferably 90 parts by mass or less, and particularly preferably 85 parts by mass or less. Within the above range, the effect tends to be better obtained.

[0115] In the rubber composition, the content of the liquid plasticizer is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, further preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less, and may be 0 parts by mass, based on 100 parts by mass of the total rubber components contained in the rubber composition. When the content is within the above range, the effect tends to be better. The content of the liquid plasticizer also includes the amount of oil contained in the oil-extended rubber.

[0116] Examples of the plasticizer include the modified polymers (the modified resins and the modified thermoplastic elastomers), and other plasticizers include oils and the like. Examples of the oil include process oil, vegetable oil, or a mixture thereof. Examples of the process oil include paraffin-based process oil, aromatic process oil, naphthenic process oil, etc. Examples of the vegetable oil include castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, peanut oil, rosin, pine oil, pine tar, tall oil, corn oil, rice oil, safflower oil, sesame oil, olive oil, sunflower oil, palm kernel oil, camellia oil, jojoba oil, macadamia nut oil, and tung oil. Among them, process oil (paraffin-based process oil, aromatic process oil, naphthenic process oil, etc.) and vegetable oil are preferred.

[0117] In the rubber composition, the content of the oil is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, further preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less, and may be 0 parts by mass, based on 100 parts by mass of the total rubber components contained in the rubber composition. When the content is within the above range, the effect tends to be better obtained. The content of the oil also includes the oil contained in the oil-extended rubber.

[0118] Examples of liquid plasticizers and solid plasticizers that can be used include products from Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Arizona Chemical Company, Nitto Chemical Co., Ltd., Nippon Shokubai Co., Ltd., JXTG Nippon Oil & Energy Corporation, Arakawa Chemical Industries, Ltd., and Taoka Chemical Co., Ltd.

[0119] (Other components constituting the rubber composition) From the viewpoints of crack resistance, ozone resistance, and the like, the rubber composition preferably contains an antioxidant.

[0120] The antiaging agent is not particularly limited, and examples thereof include naphthylamine-based antiaging agents such as phenyl-α-naphthylamine; diphenylamine-based antiaging agents such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N,N'-di-2-naphthyl-p-phenylenediamine, Examples of the antioxidant include p-phenylenediamine antioxidants such as amines; quinoline antioxidants such as polymerized 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol antioxidants such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol; and bis, tris, and polyphenol antioxidants such as tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane. Among these, p-phenylenediamine antioxidants and quinoline antioxidants are preferred, and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and polymerized 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. Commercially available products include those from Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Co., Ltd., and Flexis Co., Ltd.

[0121] In the rubber composition, the content of the antioxidant is preferably 0.2 parts by mass or more, more preferably 0.5 parts by mass or more, based on 100 parts by mass of the total rubber components contained in the rubber composition. By making the content equal to or more than the lower limit, sufficient ozone resistance tends to be obtained. The content is preferably 7.0 parts by mass or less, more preferably 4.0 parts by mass or less. By making the content equal to or less than the upper limit, good appearance tends to be obtained.

[0122] The rubber composition may contain stearic acid. The content of stearic acid in the rubber composition is preferably 0.5 to 10 parts by mass or more, and more preferably 0.5 to 5 parts by mass, based on 100 parts by mass of the total rubber components contained in the rubber composition.

[0123] As the stearic acid, any conventionally known product can be used, for example, products available from NOF Corp., Kao Corp., Fujifilm Wako Pure Chemical Industries, Ltd., Chiba Fatty Acid Co., Ltd., and the like.

[0124] The rubber composition may contain zinc oxide. The content of zinc oxide in the rubber composition is preferably 0.5 to 10 parts by mass, and more preferably 1 to 5 parts by mass, based on 100 parts by mass of the total rubber components contained in the rubber composition.

[0125] As the zinc oxide, any known zinc oxide can be used, for example, products available from Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Seido Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc.

[0126] The rubber composition may contain wax. The content of the wax in the rubber composition is preferably 0.5 to 10 parts by mass, and more preferably 1 to 5 parts by mass, based on 100 parts by mass of the total rubber components contained in the rubber composition.

[0127] The wax is not particularly limited, and examples thereof include petroleum waxes, natural waxes, etc. Also, synthetic waxes obtained by refining or chemically treating multiple waxes can be used. These waxes may be used alone or in combination of two or more kinds.

[0128] Examples of petroleum waxes include paraffin wax and microcrystalline wax. Examples of natural waxes are not particularly limited as long as they are derived from resources other than petroleum, and include, for example, vegetable waxes such as candelilla wax, carnauba wax, Japan wax, rice wax, and jojoba wax; animal waxes such as beeswax, lanolin, and spermaceti; mineral waxes such as ozokerite, ceresin, and petrolactam; and refined products thereof. Examples of commercially available products include products from Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., and Seiko Chemical Co., Ltd.

[0129] The rubber composition may contain sulfur in order to form an appropriate amount of crosslinked chains in the polymer chains and to provide a good balance of the above-mentioned performances.

[0130] In the rubber composition, the sulfur content is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 0.7 parts by mass or more, based on 100 parts by mass of the total rubber components contained in the rubber composition. The content is preferably 6.0 parts by mass or less, more preferably 4.0 parts by mass or less, and even more preferably 3.0 parts by mass or less.

[0131] Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, soluble sulfur, etc., which are commonly used in the rubber industry. Commercially available products include those from Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemical Industry Co., Ltd., Flexis Corporation, Nippon Kanzuri Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc. These may be used alone or in combination of two or more kinds.

[0132] The rubber composition may contain a vulcanization accelerator. The content of the vulcanization accelerator in the rubber composition is usually 0.3 to 10 parts by mass, and preferably 0.5 to 7 parts by mass, based on 100 parts by mass of the total rubber components contained in the rubber composition.

[0133] The type of vulcanization accelerator is not particularly limited, and commonly used ones can be used. Examples of the vulcanization accelerator include thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, and N-cyclohexyl-2-benzothiazyl sulfenamide; thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), and tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazole sulfenamide, Nt-butyl-2-benzothiazolyl sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, and N,N'-diisopropyl-2-benzothiazole sulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, di-orthotolyl guanidine, and orthotolyl biguanidine. These may be used alone or in combination of two or more. Among them, from the viewpoint of the balance of performance, sulfenamide vulcanization accelerators and guanidine vulcanization accelerators are preferred.

[0134] In addition to the above-mentioned components, the rubber composition may contain additives such as a release agent and a pigment, which are generally used in accordance with the field of application.

[0135] The rubber composition can be produced by a known method. For example, the rubber composition can be produced by kneading each component using a rubber kneading device such as an open roll or a Banbury mixer, and crosslinking as necessary. As for the kneading conditions, the kneading temperature is usually 50 to 200°C, preferably 80 to 190°C, and the kneading time is usually 30 seconds to 30 minutes, preferably 1 minute to 30 minutes.

[0136] The tire components for which the rubber composition is used are not particularly limited, but the rubber composition can be suitably used for the tread (cap tread).

[0137] The rubber composition can be suitably used for tires. Examples of tires include pneumatic tires and non-pneumatic tires, and among these, pneumatic tires are preferred. In particular, the rubber composition can be suitably used as summer tires (summer tires), winter tires (studless tires, snow tires, studded tires, etc.), all-season tires, etc. Tires can be used as passenger car tires, large passenger car tires, large SUV tires, heavy load tires such as trucks and buses, light truck tires, two-wheeled automobile tires, racing tires (high performance tires), etc. Among these, the rubber composition can be suitably used for passenger car tires and light truck tires.

[0138] A tire is manufactured by a conventional method using the rubber composition. For example, a rubber composition containing various materials such as modified polymer-extended rubber is extruded in an unvulcanized state to match the shape of a tire component, and molded together with other tire components in a conventional manner on a tire building machine to form an unvulcanized tire, which is then heated and pressurized in a vulcanizer to manufacture a tire.

[0139] A suitable example of the tire is a tire having a tread rubber layer, the tread rubber layer having at least a surface-side tread rubber layer arranged on the surface side of the tire and an inner tread rubber layer arranged radially inward of the surface-side tread rubber layer, the surface-side tread rubber layer being made of the above-mentioned rubber composition, and the inner tread rubber layer being made of a rubber composition different from the rubber composition.

[0140] Hereinafter, an example of a preferred embodiment of the tire will be described with reference to the drawings. Fig. 1 is a cross-sectional view showing a part of a passenger vehicle tire according to one embodiment of the present invention. Note that Fig. 1 illustrates a passenger vehicle tire, but the tire can also be applied to the other tires mentioned above.

[0141] In Fig. 1, the up-down direction is the tire radial direction, the left-right direction is the tire axial direction, and the direction perpendicular to the paper surface is the tire circumferential direction. A passenger vehicle tire 1 includes a tread portion 7, a pair of sidewall portions 8 extending radially inward from both ends of the tread portion 7, bead portions 3 located at the inner ends of each sidewall portion 8, and a chafer 2 located on an upper portion of the rim. A carcass 10 is bridged between the bead portions 3 on both sides, and a breaker portion 9 is disposed on the outer side of the carcass 10 in the tire radial direction.

[0142] The carcass 10 is formed from one or more carcass plies in which carcass cords are arranged. The carcass ply passes from the tread portion 7 through the sidewall portion 8, and is folded back from the inside to the outside in the tire axial direction around the bead core 4 and the bead apex 5 extending from the upper end of the bead core 4 toward the sidewall, and is secured thereto. The breaker portion 9 is made up of two or more breaker plies in which breaker cords are arranged, and the breaker cords are arranged in different directions so that they cross between the breaker plies. A band 6 is arranged on the upper side of the breaker portion 9 to protect the breaker portion 9.

[0143] The tread portion 7 is composed of a surface side tread rubber layer 7c arranged on the side that comes into contact with the road surface, and an inner tread rubber layer 7b arranged on the radially inner side of the surface side tread rubber layer 7c. Note that, although Fig. 1 shows an example of a two-layer structure tread composed of the surface side tread rubber layer 7c and the inner tread rubber layer 7b, the present invention can be applied to any multi-layer structure tread, and can be applied to a two-layer structure tread, a three-layer structure tread, or a tread with a structure of four or more layers.

[0144] Regarding the multi-layer tread structure in the preferred embodiment of the tire, a preferred form may be, for example, in the case of a two-layer tread, a form in which the surface side tread rubber layer constitutes the outermost layer (first layer) of the two-layer tread, and the inner tread rubber layer constitutes the second layer arranged adjacent to the inner side of the outermost layer in the tire radial direction. In the case of a three-layer structure tread, examples of the configuration include a configuration in which a surface side tread rubber layer constitutes the outermost layer (first layer) of the three-layer structure tread, a rubber layer different from the surface side tread rubber layer and the inner tread rubber layer constitutes a second layer arranged adjacent to the outermost layer on the radially inner side of the tire, and the inner tread rubber layer constitutes a third layer (innermost layer of the tread rubber layer) arranged adjacent to the radially inner side of the second layer, and a configuration in which a rubber layer different from the surface side tread rubber layer and the inner tread rubber layer constitutes the outermost layer (first layer) of the three-layer structure tread, the surface side tread rubber layer constitutes the second layer arranged adjacent to the radially inner side of the outermost layer, and the inner tread rubber layer constitutes the third layer (innermost layer of the tread rubber layer) arranged adjacent to the radially inner side of the second layer.

[0145] In the tire 1 having the two-layer structure tread of FIG. 1, the rubber composition for the surface side tread rubber layer constituting the surface side tread rubber layer 7c is composed of a rubber composition containing the above-mentioned modified polymer extended rubber, and the rubber composition for the inner tread rubber layer constituting the inner tread rubber layer 7b is composed of a rubber composition different from the rubber composition for the surface side tread rubber layer.

[0146] Examples of the rubber components, fillers, plasticizers (such as the modified resins and thermoplastic elastomers) and other components (such as antioxidants) that can be used in the rubber composition for the inner tread rubber layer include those similar to those in the rubber composition described above.

[0147] In the rubber composition for the inner tread rubber layer, the content of the isoprene-based rubber in 100% by mass of the total rubber components contained in the rubber composition for the inner tread rubber layer is preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more. When the content is within the above range, the effect tends to be better obtained.

[0148] In the rubber composition for the inner tread rubber layer, the nitrogen adsorption specific surface area (N2SA) of the carbon black is preferably 50 m 2 / g or more, more preferably 60m 2 / g or more. The N2SA is preferably 200m 2 / g or less, more preferably 180m 2 / g or less, more preferably 150m 2 Within the above range, there is a tendency for the effect to be better obtained.

[0149] In the rubber composition for the inner tread rubber layer, the content of carbon black is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, based on 100 parts by mass of the total rubber components contained in the rubber composition for the inner tread rubber layer. The content is preferably 150 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 80 parts by mass or less. When the content is within the above range, the effect tends to be better obtained.

[0150] In the rubber composition for the inner tread rubber layer, the content of the plasticizer and the content of other components (such as the content of the antioxidant) can be appropriately set, and for example, the same ranges as those of the above-mentioned rubber composition can be applied.

[0151] In particular, the content of the liquid plasticizer in both the rubber composition for the surface side tread rubber constituting the surface side tread rubber layer and the rubber composition for the inner tread rubber layer constituting the inner tread rubber layer is preferably 50 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, and may be 0 parts by mass, relative to 100 parts by mass of the total rubber components contained in the rubber composition. The lower limit is not particularly limited, but may be 1 part by mass or more, or 3 parts by mass or more. Within the above range, the effect tends to be better obtained. The content of the liquid plasticizer also includes the amount of oil contained in the oil-extended rubber. EXAMPLES

[0152] The present invention will be specifically described based on examples, but the present invention is not limited to these examples.

[0153] The various chemicals used in the production examples are described below. SBR1 to SBR3, BR1: Manufacturing Examples 1-1 and 1-2 below Hydrogenated SBR: Production Example 1-3 below DCPD (non-hydrogenated): Oppera PR 383 manufactured by ExxonMobil (DCPD resin, softening point 103℃) Hydrogenated DCPD: ExxonMobil's Oppera PR 100 (hydrogenated DCPD resin, softening point 140°C) C5-C9 resin: Eneos PD104 (softening point 103°C) C9 resin: SYLVARES SA85 (α-methylstyrene resin [copolymer of α-methylstyrene and styrene], softening point 85°C) manufactured by Arizona Chemical Co. Allyltriethoxysilane 3-Aminopropyltriethoxysilane N-Acetylethylenediamine 4-Pyrrolidinylethylstyrene Modified Resins 1 to 5: Production Examples 2-1 to 2-5 below Modified TPE: Production Example 2-6 below

[0154] (Production Example 1-1: Production of SBR1 (modified SBR)) 547g of 1,3-butadiene, 173g of styrene, 6.1ml of tetrahydrofuran, and 5.0ml of ethylene glycol diethyl ether were added to a polymerization reactor in a dry methylcyclohexane solvent, and 13.1mmol of n-butyllithium was added as an n-hexane solution to carry out polymerization. 11.1mmol of 3-diethylaminopropyltriethoxysilane was added to obtain SBR1 shown in Table 1, which has an aminoalkoxyl modified group at the end.

[0155] (Production Example 1-2: Production of SBR2-3 (modified SBR) and BR1 (modified BR)) SBR2 to 3 (modified SBR) and BR1 (modified BR) shown in Table 1 were obtained by the same method as in the production of SBR1 (modified SBR).

[0156] (Production Example 1-3: Production of Hydrogenated SBR) Hydrogenated SBR was obtained in the same manner as SBR1, except that the polymer obtained in the production of SBR1 (modified SBR) was hydrogenated. That is, after the polymerization conversion reaction in SBR1, ethanol was added to stop the polymerization reaction, and then hydrogen gas was supplied at a pressure of 0.4 MPa-Gauge while stirring for 20 minutes to react with unreacted lithium at the polymer end to obtain lithium hydride. Hydrogen gas was supplied at a pressure of 0.7 MPa-Gauge and a reaction temperature of 90°C, and hydrogenation was performed using a catalyst mainly composed of titanocene dichloride. When the absorption of hydrogen reached an integrated amount that corresponds to the desired hydrogenation rate, the reaction temperature was set to room temperature, the hydrogen pressure was returned to normal pressure, and the reaction solution was removed from the reaction vessel, stirred and poured into water, and the solvent was removed by steam stripping, to obtain hydrogenated SBR (modified hydrogenated SBR) shown in Table 1.

[0157] [Table 1]

[0158] (Production Example 2-1: Production of Modified Resin 1) Modified resin 1 shown in Table 2 was obtained by adding allyltriethoxysilane to DCPD (non-hydrogenated).

[0159] (Production Example 2-2: Production of Modified Resin 2) Modified resin 2 shown in Table 2 was obtained by reacting hydrogenated DCPD with aminopropyltriethoxysilane.

[0160] (Production Example 2-3: Production of Modified Resin 3) Modified resin 3 shown in Table 2 was obtained by reacting a C5-C9 resin with aminopropyltriethoxysilane.

[0161] (Production Example 2-4: Production of Modified Resin 4) Modified resin 4 shown in Table 2 was obtained by reacting a C5-C9 resin with acetylethylenediamine.

[0162] (Production Example 2-5: Production of Modified Resin 5) The modified resin 5 shown in Table 2 was obtained by reacting the C9 resin with pyrrolidinylethylstyrene.

[0163] (Production Example 2-6: Production of modified TPE) The autoclave with a stirrer and a jacket was washed, dried, and substituted with nitrogen, and a cyclohexane solution (concentration 20% by mass) containing 10 parts by mass of styrene purified in advance was added. Then, n-butyl lithium and tetramethylethylenediamine were added, and polymerization was carried out at 70 ° C. for 1 hour, and then a cyclohexane solution (concentration 20% by mass) containing 80 parts by mass of butadiene purified in advance was added and polymerization was carried out at 70 ° C. for 1 hour, and then a cyclohexane solution (concentration 20% by mass) containing 10 parts by mass of styrene was added and polymerization was carried out at 70 ° C. for 1 hour. Then, aminopropyltriethoxysilane was reacted as a modifier in an equimolar amount with respect to the n-butyl lithium used in the polymerization. Then, alcohol was added to stop the reaction, and 1 g of 2,6-tert-butyl-p-cresol was added to the reaction solution, and the modified styrene / butadiene block copolymer (modified TPE (modified thermoplastic elastomer)) shown in Table 2 was obtained by reprecipitation purification.

[0164] [Table 2]

[0165] (Production Example 3-1: Production of Modified Polymer Extended Rubber 1) To the SBR1 solution obtained in Production Example 1-1, a methylcyclohexane solution of modified resin 1 (360 g) prepared separately in Production Example 2-1 was added, mixed well, and the solvent was removed to obtain modified polymer extended rubber 1 (MB1 (SBR1 / modified resin 1 = 100 / 50)).

[0166] (Production Example 3-2: Production of Modified Polymer Extended Rubbers 2 to 9) According to Table 3, modified polymer extended rubbers 2 to 9 (MB2 to MB9) were obtained in the same manner as in Production Example 3-1.

[0167] [Table 3]

[0168] The various chemicals used in the examples and comparative examples will be described below. (Captread) MB1 to MB7: Preparation Examples 3-1 and 3-2 BR2: BR150B manufactured by Ube Industries (cis content 97% by mass, Tg-110°C) NR:TSR20(Tg-62℃) SBR1: Preparation Example 1-1 Silica 1: Ultrasil VN3 (N2SA175m) manufactured by Evonik Degussa 2 / g) Silica 2: Rhodia Zeosil Premium 200MP (N2SA220m 2 / g) Silica 3: Solvay Premium SW (N2SA275m 2 / g) Silane coupling agent 1: Evonik Degussa Si266 (bis(3-triethoxysilylpropyl) disulfide) Silane coupling agent 2: Evonik Degussa Si69 (bis(3-triethoxysilylpropyl)tetrasulfide) Silane coupling agent 3: Momentive NXT silane (3-octanoylthiopropyltriethoxysilane) Carbon black: Diablack A (N110, N2SA142m) manufactured by Mitsubishi Chemical Corporation 2 / g, DBP116ml / 100g) Hydrogenated DCPD: ExxonMobil Escorez5320 (hydrogenated DCPD resin) DCPD (non-hydrogenated): ExxonMobil DCPD resin Oil: H&R VIVATEC500 (TDAE oil) Stearic acid: NOF Corp. stearic acid camellia beads Zinc oxide: Zinc oxide type 2 manufactured by Mitsui Mining & Smelting Co., Ltd. Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Industry Co., Ltd. Vulcanization accelerator 1: Noccelaer D (N,N'-diphenylguanidine (DPG)) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator 2: Noccela CZ (N-cyclohexyl-2-benzothiazolyl sulfenamide) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Anti-aging agent: Nocrac 6C (N-(1,3-dimethylbutyl)-N-phenyl-p-phenylenediamine) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0169] (Base tread) NR:TSR20 BR: BR150B (cis content 97% by mass) manufactured by Ube Industries, Ltd. Carbon black: Cabot Japan Co., Ltd. Show Black N330 (N2SA75m 2 / g) Oil: Diana Process AH-24 manufactured by Idemitsu Kosan Co., Ltd. Anti-aging agent: Nocrac 6C (N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine) (6PPD) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Stearic acid: NOF Corp. stearic acid camellia beads Zinc oxide: Zinc oxide type 2 manufactured by Mitsui Mining & Smelting Co., Ltd. Sulfur: Seimi sulfur manufactured by Nippon Kanretsu Kogyo Co., Ltd. (oil content: 10%) Vulcanization accelerator TBBS: Noccela NS manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0170] <Examples and Comparative Examples> (Tire manufacturing) According to the composition shown in Table 4, the materials listed in Table 4, except for sulfur, vulcanization accelerator, and antioxidant, were kneaded for 5 minutes at 150°C using a 1.7L Banbury mixer manufactured by Kobe Steel, Ltd. to obtain a kneaded product. Next, sulfur, vulcanization accelerator, and antioxidant were added to the kneaded product obtained, and the mixture was kneaded for 5 minutes at 80°C using an open roll to obtain an unvulcanized rubber composition. The obtained unvulcanized rubber composition was molded into the shape of a cap tread, and was laminated together with a base tread and other tire components having the composition shown in Table 5 on a tire building machine to form an unvulcanized tire. The tire was then vulcanized at 170°C for 10 minutes to produce a test tire (size: 195 / 65R15, passenger car tire).

[0171] The obtained test tires were evaluated as follows, and the results are shown in Table 4. The reference comparative example in Table 4 was Comparative Example 1.

[0172] <Evaluation> (Wear resistance) Each test tire was fitted to a domestically produced FF 2000cc vehicle, and the tire tread depth was measured after a distance of 5000km travelled at a speed of 100-150km / h. The distance travelled when the tire groove depth was reduced by 1mm was calculated and indexed using the following formula. The higher the index, the better the wear resistance. Abrasion resistance index = (mileage when tread depth is reduced by 1 mm) / (mileage when tread depth of standard comparative tire is reduced by 1 mm) x 100

[0173] (Rubber strength) After the above-mentioned wear resistance test, the tires were checked for the presence or absence of chipping or tread breaks. The condition of the reference comparative example was set as 100 and indexed. The higher the index, the better the rubber strength.

[0174] (Wet grip performance) The test tires were mounted on a domestically produced 2000cc FF vehicle, and the vehicle was driven on a wet 25°C road surface at the Asahikawa test course in Hokkaido. The vehicle was then locked at 100km / h, and the stopping distance was measured. The comparative reference tire was set at 100 and the results were expressed as an index using the following formula. The higher the index, the better the wet grip performance (wet braking performance). (Wet grip performance index) = (stopping distance of standard comparative example) / (stopping distance of each compound) x 100

[0175] (High speed wet grip performance) The test tire was mounted on a domestic 2000cc FF vehicle, and the vehicle was driven on a wet 25°C road surface at the Asahikawa test course in Hokkaido. The vehicle was then locked at 150km / h, and the stopping distance was measured. The standard comparative example was set to 100, and the results were expressed as an index using the following formula. The higher the index, the better the high-speed wet grip performance (wet braking performance at high speed). (High-speed wet grip performance index) = (stopping distance of standard comparison example) / (stopping distance of each compound) x 100

[0176] (low fuel consumption) The test tires were mounted on a domestically manufactured 2000cc FF vehicle, and the vehicle was driven on a dry road surface at 25°C at the Okayama test course. The accelerator was released at a speed of 60km / h, and the distance traveled until the vehicle stopped was measured. The standard comparative example was set to 100, and the results were expressed as an index using the following formula. The higher the index, the better the fuel economy. (Fuel economy index) = (Distance traveled for each formulation) / (Distance traveled for the standard comparative example) x 100

[0177] [Table 4]

[0178] [Table 5]

[0179] As can be seen from Table 4, the tires of the examples in which a rubber composition containing a modified polymer-extended rubber in which rubber component A is extended with at least one modified polymer selected from the group consisting of modified resins having functional groups that have affinity with silica, and modified thermoplastic elastomers having functional groups that have affinity with silica, were used had excellent overall performance (expressed as the sum of five indexes of abrasion resistance, rubber strength, wet grip performance, high-speed wet grip performance, and fuel economy) in terms of abrasion resistance, rubber strength, wet grip performance, high-speed wet grip performance, and fuel economy. [Explanation of symbols]

[0180] 1 Passenger car tires 2 Chafer 3 Bead section 4 Bead Core 5 Bead Apex 6 Bands 7 Tread 7b Inner tread rubber layer 7c Surface tread rubber layer 8 Sidewall 9 Breaker Section 10. Carcass

Claims

1. A rubber composition comprising a modified polymer-extended rubber in which a rubber component A having a glass transition temperature of -40°C or lower is extended with at least one modified polymer selected from the group consisting of a modified resin having a functional group that has affinity for silica, and a modified thermoplastic elastomer having a functional group that has affinity for silica.

2. 2. The rubber composition according to claim 1, wherein the rubber component A has a number average molecular weight of 150,000 or more.

3. 3. The rubber composition according to claim 1, wherein the functional group is at least one selected from the group consisting of a group represented by SiOR (R is a hydrogen atom or a hydrocarbon group), an alkoxysilyl group, an amino group, a hydroxyl group, an epoxy group, and a carboxyl group, each of which may have a substituent.

4. The resin constituting the skeleton of the modified resin is C ５ based resin, C ５ -C ９ based resin, C ９ The rubber composition according to any one of claims 1 to 3, wherein the resin is at least one selected from the group consisting of a terpene-based resin, a terpene-aromatic compound-based resin, a rosin-based resin, a dicyclopentadiene resin, and an alkylphenol-based resin.

5. 5. The rubber composition according to claim 1, wherein the thermoplastic elastomer constituting the skeleton of the modified thermoplastic elastomer has a block made of an aromatic vinyl monomer.

6. 6. The rubber composition according to claim 1, wherein the rubber component A contains a modified rubber having a functional group having affinity for silica.

7. The rubber composition according to any one of claims 1 to 6, wherein the rubber component A includes at least one rubber selected from the group consisting of a styrene-butadiene rubber and a butadiene rubber.

8. The modified polymer-extended rubber is produced by polymerizing the rubber component A in an organic solvent, and adding a solution of the modified resin and / or the modified thermoplastic elastomer to the resulting solution. The rubber composition according to any one of claims 1 to 7.

9. 9. The rubber composition according to claim 1, wherein the content of the liquid plasticizer is 20 parts by mass or less based on 100 parts by mass of the total rubber component.

10. The rubber composition according to any one of claims 1 to 8, wherein the content of the liquid plasticizer per 100 parts by mass of the total rubber component is 10 parts by mass or less.

11. The rubber composition according to any one of claims 1 to 10, wherein the content of silica per 100 parts by mass of the total rubber component is 30 parts by mass or more.

12. The rubber composition according to any one of claims 1 to 10, wherein the content of silica per 100 parts by mass of the total rubber component is 80 parts by mass or more.

13. A tire having a tread rubber layer, The tread rubber layer has at least a surface side tread rubber layer disposed on a surface side of the tire, and an inner tread rubber layer disposed on the inner side in the tire radial direction of the surface side tread rubber layer, The surface side tread rubber layer is made of the rubber composition according to any one of claims 1 to 12, The tire wherein the inner tread rubber layer is made of a rubber composition different from the rubber composition mentioned above.

14. The tire according to claim 13, wherein the rubber composition constituting the surface side tread rubber layer and the rubber composition constituting the inner tread rubber layer each contain a liquid plasticizer in an amount of 20 parts by mass or less per 100 parts by mass of the total rubber component.

Images