JP2019194290A - Tire rubber composition and pneumatic tire - Google Patents

Abstract

To provide a tire rubber composition that can comprehensively improve fuel economy, wear resistance and dry grip performance, and a pneumatic tire made with the rubber composition.SOLUTION: This invention relates to a tire rubber composition that has a rubber component containing styrene-butadiene rubber, butadiene rubber and isoprene rubber, and silica of 70 pts.mass or more relative to the rubber component 100 pts.mass. The styrene-butadiene rubber is composed of a plurality of styrene-butadiene rubbers. For the plurality of styrene-butadiene rubbers, differences among them in vinyl amounts is 25 mass% or more.SELECTED DRAWING: None

Description

The present invention relates to a tire rubber composition and a pneumatic tire.

In recent years, due to increasing interest in environmental problems, not only fuel consumption reduction is required for automobiles, but also good wear resistance and the like are required for rubber compositions used in automobile tires. Yes.

Tires are required to have grip performance such as dry grip performance in order to ensure safety. In order to meet this demand, styrene butadiene rubber is widely used as a rubber component. However, when styrene butadiene rubber is used, fuel economy and wear resistance tend to decrease. Thus, grip performance, fuel efficiency, and wear resistance are contradictory, and it is difficult to improve them comprehensively.

The present invention provides a rubber composition for a tire that solves the above-mentioned problems and can improve fuel economy, wear resistance, and dry grip performance comprehensively, and a pneumatic tire produced using the rubber composition. With the goal.

The present invention comprises a rubber component comprising styrene butadiene rubber, butadiene rubber and isoprene-based rubber, and silica having a content of 70 parts by mass or more with respect to 100 parts by mass of the rubber component, and the styrene butadiene rubber comprises a plurality of styrene. The styrene-butadiene rubber is composed of butadiene rubber, and each of the plurality of styrene-butadiene rubbers relates to a rubber composition for a tire having a difference in vinyl amount of 25% by mass or more.

In 100% by mass of the rubber component, the content of the isoprene-based rubber is preferably 10% by mass or more.

In 100% by mass of the rubber component, the content of low cis butadiene rubber having a cis content of 50% by mass or less is preferably 10% by mass or more.

The rubber composition preferably contains a styrene resin.

The rubber composition preferably contains a mercapto silane coupling agent.

The nitrogen adsorption specific surface area of the silica is preferably 220 m ² / g or more.

The present invention also relates to a pneumatic tire produced using the rubber composition.

According to the present invention, a plurality of styrene butadiene rubbers containing a styrene butadiene rubber, a butadiene rubber and an isoprene-based rubber, and a predetermined amount of silica and having a vinyl difference within a predetermined range are used as the styrene butadiene rubber. Therefore, the fuel composition, wear resistance and dry grip performance can be improved comprehensively.

The rubber composition for tires of the present invention contains styrene butadiene rubber (SBR), butadiene rubber (BR) and isoprene-based rubber, and a predetermined amount of silica, and the difference in vinyl amount as SBR is within a predetermined range. A plurality of SBRs are used.

The rubber composition has the above-described effects, which are presumed to be achieved by the following effects.
When SBR is used as the main component of the rubber component, the grip performance tends to be improved, but the fuel economy and wear resistance tend to be reduced. On the other hand, in the rubber composition, BR and isoprene-based rubber are used as rubber components other than SBR, the silica amount is adjusted to a specific range, and further, the difference in vinyl amount is within a predetermined range as SBR. By using a plurality of SBR, the silica is well dispersed in the rubber composition. Thereby, it is considered that fuel efficiency, wear resistance, and dry grip performance are comprehensively improved.

The rubber composition contains SBR as a rubber component.
It does not specifically limit as SBR, For example, emulsion polymerization styrene butadiene rubber (E-SBR), solution polymerization styrene butadiene rubber (S-SBR), etc. can be used. SBR may be either non-modified SBR or modified SBR.

The modified SBR may be any SBR having a functional group that interacts with a filler such as silica. For example, at least one terminal of SBR is modified with a compound having a functional group (modifier). SBR (terminal-modified SBR having the functional group at the terminal), main-chain modified SBR having the functional group at the main chain, and main-chain terminal-modified SBR having the functional group at the main chain and the terminal (for example, in the main chain) A hydroxyl group modified (coupled) with a polyfunctional compound having the above functional group and having at least one terminal modified with the above modifier with a main chain terminal modified SBR) or a polyfunctional compound having two or more epoxy groups in the molecule. And terminal-modified SBR into which an epoxy group has been introduced.

Examples of the functional groups include amino groups, amide groups, silyl groups, alkoxysilyl groups, isocyanate groups, imino groups, imidazole groups, urea groups, ether groups, carbonyl groups, oxycarbonyl groups, mercapto groups, sulfide groups, disulfides. Group, sulfonyl group, sulfinyl group, thiocarbonyl group, ammonium group, imide group, hydrazo group, azo group, diazo group, carboxyl group, nitrile group, pyridyl group, alkoxy group, hydroxyl group, oxy group, epoxy group, etc. . These functional groups may have a substituent. Among these, an amino group (preferably an amino group in which a hydrogen atom of the amino group is substituted with an alkyl group having 1 to 6 carbon atoms), an alkoxy group (preferably an alkoxy group having 1 to 6 carbon atoms), an alkoxysilyl group ( An alkoxysilyl group having 1 to 6 carbon atoms) and an amide group are preferable.

（式中、Ｒ^１、Ｒ^２及びＲ^３は、同一又は異なって、アルキル基、アルコキシ基、シリルオキシ基、アセタール基、カルボキシル基（−ＣＯＯＨ）、メルカプト基（−ＳＨ）又はこれらの誘導体を表す。Ｒ^４及びＲ^５は、同一又は異なって、水素原子又はアルキル基を表す。Ｒ^４及びＲ^５は結合して窒素原子と共に環構造を形成してもよい。ｎは整数を表す。） As the modified SBR, SBR modified with a compound (modifier) represented by the following formula is particularly preferable.

Wherein R ¹ , R ² and R ³ are the same or different and represent an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group (—COOH), a mercapto group (—SH) or a derivative thereof. R ⁴ and R ⁵ may be the same or different and each represents a hydrogen atom or an alkyl group, R ⁴ and R ⁵ may be bonded to form a ring structure with a nitrogen atom, and n represents an integer.)

As the modified SBR modified with the compound represented by the above formula (modifier), the polymerization terminal (active terminal) of the styrene butadiene rubber (S-SBR) of solution polymerization is the compound represented by the above formula. Modified SBR (modified SBR described in JP 2010-111753 A) is preferably used.

R ¹ , R ² and R ³ are preferably alkoxy groups (preferably having 1 to 8 carbon atoms, more preferably having 1 to 4 carbon atoms). R ⁴ and R ⁵ are 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 still more preferably 3. In the case of forming a ring structure with a nitrogen atom bonded to R ⁴ and R ^5, it is preferably a 4- to 8-membered ring. The alkoxy group also includes a cycloalkoxy group (such as cyclohexyloxy group) and an aryloxy group (such as phenoxy group and benzyloxy group).

Specific examples of the modifier include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltri Examples include methoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, and 3-diethylaminopropyltriethoxysilane. Of these, 3-dimethylaminopropyltrimethoxysilane, 3-dimethylaminopropyltriethoxysilane, and 3-diethylaminopropyltrimethoxysilane are preferable. These may be used alone or in combination of two or more.

As the modified SBR, modified SBR modified with the following compound (modifier) can also be suitably used. Examples of the modifier include polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether, glycerin triglycidyl ether, trimethylol ethane triglycidyl ether, trimethylol propane triglycidyl ether; Polyglycidyl ethers of aromatic compounds having the following phenol groups; polyepoxy compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, polyepoxidized liquid polybutadiene; 4,4′-diglycidyl-diphenyl Epoxy group-containing tertiary amines such as methylamine and 4,4′-diglycidyl-dibenzylmethylamine; diglycidylaniline, N, N′-diglycidyl-4-glycidyloxyaniline, diglycidyl Luso toluidine, tetraglycidyl meta-xylene diamine, tetraglycidyl diaminodiphenylmethane, tetraglycidyl -p- phenylenediamine, diglycidyl aminomethyl cyclohexane, diglycidyl amino compounds such as tetraglycidyl-1,3-bisaminomethylcyclohexane;

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

(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- (methyldioxy) Sulfide group-containing silane compounds such as propoxysilyl) propyl] sulfide, (trimethylsilyl) [3- (methyldibutoxysilyl) propyl] sulfide;

N-substituted aziridine compounds such as ethyleneimine and propyleneimine; methyltriethoxysilane, N, N-bis (trimethylsilyl) -3-aminopropyltrimethoxysilane, N, N-bis (trimethylsilyl) -3-aminopropyltriethoxy Alkoxysilanes such as silane, N, N-bis (trimethylsilyl) aminoethyltrimethoxysilane, N, N-bis (trimethylsilyl) aminoethyltriethoxysilane; 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, N, N (Thio) benzophenone compounds having an amino group and / or a substituted amino group such as N ′, N′-bis- (tetraethylamino) benzophenone; 4-N, N-dimethylaminobenzaldehyde, 4-N, N-diphenylaminobenzaldehyde , A benzaldehyde compound having an amino group and / or a substituted amino group such as 4-N, N-divinylaminobenzaldehyde; N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, N -T-butyl-2-pyrrolidone, N-substituted pyrrolidone such as N-methyl-5-methyl-2-pyrrolidone N-methyl-2-piperidone, N-vinyl-2-piperidone, N-phenyl-2-piperidone, etc. N-substituted piperidones; N-methyl-ε-caprolactam, N-phenyl-ε-capro N-substituted lactams such as cutam, N-methyl-ω-laurylactam, N-vinyl-ω-laurylactam, N-methyl-β-propiolactam, N-phenyl-β-propiolactam other,

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 (diphenyl) Amino) -2-propanone, 1,7-bis (methylethylamino) -4-heptanone, etc. can be mentioned. Of these, modified SBR modified with alkoxysilane is preferable.
In addition, modification | denaturation by the said compound (modifier) can be implemented by a well-known method.

In the rubber composition, SBR is composed of a plurality of SBRs.
In the plurality of SBRs, the difference in the amount of each vinyl may be 25% by mass or more, preferably 28% by mass or more, and preferably 50% by mass or less, more preferably 36% by mass or less. . Within the above range, the effects of the present invention tend to be obtained more favorably.

At least one of the plurality of SBRs has a vinyl amount of preferably 15% by mass or more, more preferably 24% by mass or more, and preferably 70% by mass or less, more preferably 60% by mass or less. Within the above range, the effects of the present invention tend to be obtained more favorably.
The vinyl amount (1,2-bonded butadiene unit amount) can be measured by the method described in the examples below.

At least one of the plurality of SBRs has a styrene amount of preferably 20% by mass or more, more preferably 25% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less. Within the above range, the effects of the present invention tend to be obtained more favorably.
The amount of styrene can be measured by the method described in the examples below.

At least one of the plurality of SBRs has a weight average molecular weight (Mw) of preferably 150,000 or more, more preferably 450,000 or more, and preferably 1.2 million or less, more preferably 900,000 or less. Within the above range, the effects of the present invention tend to be obtained more favorably.
Mw and Mn are measured values by gel permeation chromatography (GPC) (GPC-8000 series, manufactured by Tosoh Corp., detector: differential refractometer, column: TSKGEL SUPERMULTIPORE HZ-M, manufactured by Tosoh Corp.). Can be determined by standard polystyrene conversion.

As SBR, SBR manufactured and sold by Sumitomo Chemical Co., Ltd., JSR Co., Ltd., Asahi Kasei Co., Ltd., Nippon Zeon Co., Ltd., etc. can be used, for example.

The SBR content (total content of a plurality of SBRs) in 100% by mass of the rubber component is preferably 60% by mass or more, more preferably 70% by mass or more, and preferably 90% by mass or less, more preferably Is 80 mass% or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

The rubber composition contains BR as a rubber component.
The BR is not particularly limited, and BR having a high cis content, BR having a low cis content, BR containing a syndiotactic polybutadiene crystal, and the like can be used. The BR may be either a non-modified BR or a modified BR. Examples of the modified BR include a modified BR in which the above-described functional group is introduced. These may be used alone or in combination of two or more. Of these, low-cis butadiene rubber (Loss BR) having a cis content of 50% by mass or less is preferred. The cis content of Rhosis BR is preferably 40% by mass or less, and preferably 5% by mass or more.
The cis content can be measured by infrared absorption spectrum analysis.

As BR, for example, products such as Ube Industries, JSR, Asahi Kasei, Nippon Zeon, and the like can be used.

In the case of containing Rhosis BR, the content of Rhosis BR in 100% by mass of the rubber component is preferably 10% by mass or more, more preferably 15% by mass or more, and preferably 40% by mass or less, more preferably 35% by mass or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

The content of BR in 100% by mass of the rubber component (the total content of Rhosis BR and other BR) is preferably 10% by mass or more, preferably 15% by mass or more, and preferably 40% by mass or less. More preferably, it is 35 mass% or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

The rubber composition contains isoprene-based rubber as a rubber component.
Examples of the isoprene-based rubber include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR. As the NR, for example, those commonly used in the tire industry such as SIR20, RSS # 3, TSR20 and the like can be used. As IR, it is not specifically limited, For example, IR2200 etc. can use what is common in tire industry. As modified NR, deproteinized natural rubber (DPNR), high-purity natural rubber (UPNR), etc., modified NR, epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), grafted natural rubber, etc. Examples of the 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.

The content of the isoprene-based rubber in 100% by mass of the rubber component is preferably 10% by mass or more, more preferably 15% by mass or more, and preferably 40% by mass or less, more preferably 30% by mass or less. . Within the above range, the effects of the present invention tend to be obtained more favorably.

Examples of rubber components other than SBR, BR, and isoprene-based rubber include diene systems such as acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR), and styrene-isoprene-butadiene copolymer rubber (SIBR). Rubber. These diene rubbers may be used alone or in combination of two or more.

The rubber composition contains silica.
Examples of the silica include dry process silica (anhydrous silicic acid), wet process silica (hydrous silicic acid) and the like, but wet process silica is preferred because of the large number of silanol groups. These may be used alone or in combination of two or more.

Nitrogen adsorption specific surface area _(N 2 SA) of silica is preferably 110m ² / g or more, more preferably 150 meters ² / g or more, more preferably 200 meters ² / g or more, particularly preferably 220 m ² / g or more, Moreover, Preferably it is 300 m < ² > / g or less, More preferably, it is 260 m < ² > / g or less. Within the above range, the effects of the present invention tend to be obtained more favorably.
The nitrogen adsorption specific surface area of silica is a value measured by the BET method according to ASTM D3037-81.

Examples of silica that can be used include products such as Degussa, Rhodia, Tosoh Silica, Solvay Japan, and Tokuyama.

The content of silica with respect to 100 parts by mass of the rubber component may be 70 parts by mass or more, preferably 80 parts by mass or more, and preferably 120 parts by mass or less, more preferably 105 parts by mass or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

The rubber composition preferably contains a silane coupling agent together with silica. Thereby, there exists a tendency for the effect of this invention to be acquired more favorably.
The silane coupling agent is not particularly limited. For example, 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-trimethoxysilyl ester) 3) disulfide, bis (4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3 -Sulfide systems such as triethoxysilylpropyl methacrylate monosulfide, mercapto systems such as 3-mercaptopropyltrimethoxysilane and 2-mercaptoethyltriethoxysilane, vinyl systems such as vinyltriethoxysilane and vinyltrimethoxysilane, 3-amino Amino-based compounds such as propyltriethoxysilane and 3-aminopropyltrimethoxysilane; glycidoxy-based compounds such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; Toro propyltrimethoxysilane, 3-nitro-triethoxysilane and nitro-based, 3-chloropropyl trimethoxy silane, chloro system such as 3-chloropropyl triethoxysilane and the like. These may be used alone or in combination of two or more. Among these, a sulfide type and a mercapto type are preferable, and a mercapto type is more preferable because the effects of the present invention can be obtained better.

As the mercapto-based silane coupling agent, a compound having a structure in which a mercapto group is protected by a protecting group (for example, a compound represented by the following formula (S1)) can be used in addition to a compound having a mercapto group. .

（式中、Ｒ^１００１は−Ｃｌ、−Ｂｒ、−ＯＲ^１００６、−Ｏ（Ｏ＝）ＣＲ^１００６、−ＯＮ＝ＣＲ^１００６Ｒ^１００７、−ＯＮ＝ＣＲ^１００６Ｒ^１００７、−ＮＲ^１００６Ｒ^１００７及び−（ＯＳｉＲ^１００６Ｒ^１００７）_ｈ（ＯＳｉＲ^１００６Ｒ^１００７Ｒ^１００８）から選択される一価の基（Ｒ^１００６、Ｒ^１００７及びＲ^１００８は同一でも異なっていても良く、各々水素原子又は炭素数１〜１８の一価の炭化水素基であり、ｈは平均値が１〜４である。）であり、Ｒ^１００２はＲ^１００１、水素原子又は炭素数１〜１８の一価の炭化水素基、Ｒ^１００３は−［Ｏ（Ｒ^１００９Ｏ）_ｊ］−基（Ｒ^１００９は炭素数１〜１８のアルキレン基、ｊは１〜４の整数である。）、Ｒ^１００４は炭素数１〜１８の二価の炭化水素基、Ｒ^１００５は炭素数１〜１８の一価の炭化水素基を示し、ｘ、ｙ及びｚは、ｘ＋ｙ＋２ｚ＝３、０≦ｘ≦３、０≦ｙ≦２、０≦ｚ≦１の関係を満たす数である。）

（式中、ｖは０以上の整数、ｗは１以上の整数である。Ｒ^１１は水素、ハロゲン、分岐若しくは非分岐の炭素数１〜３０のアルキル基、分岐若しくは非分岐の炭素数２〜３０のアルケニル基、分岐若しくは非分岐の炭素数２〜３０のアルキニル基、又は該アルキル基の末端の水素が水酸基若しくはカルボキシル基で置換されたものを示す。Ｒ^１２は分岐若しくは非分岐の炭素数１〜３０のアルキレン基、分岐若しくは非分岐の炭素数２〜３０のアルケニレン基、又は分岐若しくは非分岐の炭素数２〜３０のアルキニレン基を示す。Ｒ^１１とＲ^１２とで環構造を形成してもよい。） As a particularly suitable mercapto-based silane coupling agent, a silane coupling agent represented by the following formula (S1), a binding unit A represented by the following formula (I), and a coupling unit B represented by the following formula (II) Examples include silane coupling agents.

(In the formula, R ¹⁰⁰¹ represents —Cl, —Br, —OR ¹⁰⁰⁶ , —O (O═) CR ¹⁰⁰⁶ , —ON = CR ¹⁰⁰⁶ R ¹⁰⁰⁷ , —ON = CR ¹⁰⁰⁶ R ¹⁰⁰⁷ , —NR ¹⁰⁰⁶ R ¹⁰⁰⁷ and — ( The monovalent groups (R ¹⁰⁰⁶ , R ^1007, and R ¹⁰⁰⁸ ) selected from OSiR ¹⁰⁰⁶ R ¹⁰⁰⁷ ) _h (OSiR ¹⁰⁰⁶ R ¹⁰⁰⁷ R ¹⁰⁰⁸ ) may be the same or different and each have a hydrogen atom or a carbon number of 1 to 18 R is a monovalent hydrocarbon group, h has an average value of 1 to 4, and R ¹⁰⁰² is R ¹⁰⁰¹ , a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms, and R ¹⁰⁰³ is − _{^{[O (R 1009 O) j}} ] - group ^{(. R 1009} represents an alkylene group having 1 to 18 carbon atoms, j is an integer from 1 to ^{4), R 1004} is from 1 to 18 carbon atoms Valent hydrocarbon ^{group, R 1005} represents a monovalent hydrocarbon group having 1 to 18 carbon atoms, x, y and z, x + y + 2z = 3,0 ≦ x ≦ 3,0 ≦ y ≦ 2,0 ≦ z It is a number that satisfies the relationship of ≦ 1.)

(In the formula, v is an integer of 0 or more, and w is an integer of 1 or more. R ¹¹ is hydrogen, halogen, a branched or unbranched alkyl group having 1 to 30 carbon atoms, a branched or unbranched carbon number of 2 to 2. 30 alkenyl groups, branched or unbranched alkynyl groups having 2 to 30 carbon atoms, or those in which the hydrogen at the terminal of the alkyl group is substituted with a hydroxyl group or a carboxyl group, R ¹² is branched or unbranched carbon number 1 to 30 represents an alkylene group, a branched or unbranched alkenylene group having 2 to 30 carbon atoms, or a branched or unbranched alkynylene group having 2 to 30 carbon atoms, wherein R ¹¹ and R ¹² form a ring structure. May be.)

In the formula (S1), R ¹⁰⁰⁵ , R ¹⁰⁰⁶ , R ¹⁰⁰⁷ and R ¹⁰⁰⁸ are each independently a linear, cyclic or branched alkyl group having 1 to 18 carbon atoms, an alkenyl group, an aryl group and an aralkyl group. A group selected from the group consisting of When R ¹⁰⁰² is a monovalent hydrocarbon group having 1 to 18 carbon atoms, it is selected from the group consisting of linear, cyclic or branched alkyl groups, alkenyl groups, aryl groups, and aralkyl groups. It is preferably a group. R ¹⁰⁰⁹ is preferably a linear, cyclic or branched alkylene group, and particularly preferably a linear one. R ¹⁰⁰⁴ is, for example, an alkylene group having 1 to 18 carbon atoms, an alkenylene group having 2 to 18 carbon atoms, a cycloalkylene group having 5 to 18 carbon atoms, a cycloalkylalkylene group having 6 to 18 carbon atoms, or an arylene having 6 to 18 carbon atoms. And aralkylene groups having 7 to 18 carbon atoms. The alkylene group and alkenylene group may be either linear or branched, and the cycloalkylene group, cycloalkylalkylene group, arylene group, and aralkylene group have a functional group such as a lower alkyl group on the ring. You may do it. As R ¹⁰⁰⁴ , an alkylene group having 1 to 6 carbon atoms is preferable, and a linear alkylene group such as a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, or a hexamethylene group is particularly preferable.

Specific examples of R ¹⁰⁰² , R ¹⁰⁰⁵ , R ¹⁰⁰⁶ , R ¹⁰⁰⁷ and R ¹⁰⁰⁸ in formula (S1) include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl. Group, tert-butyl group, pentyl group, hexyl group, octyl group, decyl group, dodecyl group, cyclopentyl group, cyclohexyl group, vinyl group, propenyl group, allyl group, hexenyl group, octenyl group, cyclopentenyl group, cyclo Hexenyl group, phenyl group, tolyl group, xylyl group, naphthyl group, benzyl group, phenethyl group, naphthylmethyl group and the like can be mentioned.
Examples of R ¹⁰⁰⁹ in the formula (S1) include a methylene group, an ethylene group, an n-propylene group, an n-butylene group, a hexylene group and the like as a linear alkylene group. An isopropylene group, an isobutylene group, a 2-methylpropylene group, etc. are mentioned.

Specific examples of the silane coupling agent represented by the formula (S1) include 3-hexanoylthiopropyltriethoxysilane, 3-octanoylthiopropyltriethoxysilane, 3-decanoylthiopropyltriethoxysilane, 3- Lauroylthiopropyltriethoxysilane, 2-hexanoylthioethyltriethoxysilane, 2-octanoylthioethyltriethoxysilane, 2-decanoylthioethyltriethoxysilane, 2-lauroylthioethyltriethoxysilane, 3-hexanoyl Ruthiopropyltrimethoxysilane, 3-octanoylthiopropyltrimethoxysilane, 3-decanoylthiopropyltrimethoxysilane, 3-lauroylthiopropyltrimethoxysilane, 2-hexanoylthioethyltrimethoxysilane, 2-o Motor noise Lucio ethyltrimethoxysilane, 2- deca Neu thio ethyltrimethoxysilane, and 2-lauroyl thio ethyl trimethoxysilane. These may be used alone or in combination of two or more. Of these, 3-octanoylthiopropyltriethoxysilane is particularly preferable.

In the silane coupling agent containing the bonding unit A represented by the formula (I) and the coupling unit B represented by the formula (II), the content of the bonding unit A is preferably 30 mol% or more, more preferably 50 mol. % Or more, preferably 99 mol% or less, more preferably 90 mol% or less. Further, the content of the binding unit B is preferably 1 mol% or more, more preferably 5 mol% or more, still more preferably 10 mol% or more, preferably 70 mol% or less, more preferably 65 mol% or less, More preferably, it is 55 mol% or less. Further, the total content of the binding units A and B is preferably 95 mol% or more, more preferably 98 mol% or more, and particularly preferably 100 mol%.
The content of the bond units A and B is an amount including the case where the bond units A and B are located at the terminal of the silane coupling agent. The form in the case where the bonding units A and B are located at the end of the silane coupling agent is not particularly limited as long as the units corresponding to the formulas (I) and (II) indicating the bonding units A and B are formed. .

Regarding R ¹¹ in formulas (I) and (II), examples of the halogen include chlorine, bromine, and fluorine. Examples of the branched or unbranched alkyl group having 1 to 30 carbon atoms include a methyl group and an ethyl group. Examples of the branched or unbranched alkenyl group having 2 to 30 carbon atoms include vinyl group and 1-propenyl group. Examples of the branched or unbranched alkynyl group having 2 to 30 carbon atoms include ethynyl group and propynyl group.

Regarding R ¹² in the formulas (I) and (II), examples of the branched or unbranched alkylene group having 1 to 30 carbon atoms include an ethylene group and a propylene group. Examples of the branched or unbranched C2-C30 alkenylene group include vinylene group and 1-propenylene group. Examples of the branched or unbranched alkynylene group having 2 to 30 carbon atoms include an ethynylene group and a propynylene group.

In the silane coupling agent containing the binding unit A represented by the formula (I) and the coupling unit B represented by the formula (II), the number of repeating units (v) of the connecting unit A and the number of repeating units (w) of the connecting unit B The total number of repetitions (v + w) is preferably in the range of 3 to 300.

When the silane coupling agent is contained, the content of the silane coupling agent is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, and preferably 20 parts by mass with respect to 100 parts by mass of silica. Hereinafter, it is more preferably 15 parts by mass or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

The rubber composition preferably contains a styrene resin. Thereby, there exists a tendency for the effect of this invention to be acquired more favorably.
The styrene resin is a polymer containing a styrene monomer as a constituent monomer, and examples thereof include a polymer obtained by polymerizing a styrene monomer as a main component (50% by mass or more). Specifically, styrene monomers (styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, etc.) each independently polymerized, a copolymer obtained by copolymerizing two or more styrene monomers, and a styrene monomer And copolymers with other monomers that can be copolymerized therewith.

Other monomers include acrylonitriles such as acrylonitrile and methacrylonitrile, unsaturated carboxylic acids such as acrylics and methacrylic acid, unsaturated carboxylic acid esters such as methyl acrylate and methyl methacrylate, terpenes, chloroprene, Examples thereof include conjugated dienes such as butadiene isoprene, olefins such as 1-butene and 1-pentene; α, β-unsaturated carboxylic acids such as maleic anhydride or acid anhydrides thereof, and the like. These may be used individually by 1 type and may use 2 or more types together.

The styrene resin is an α-methylstyrene resin (α-methylstyrene homopolymer, copolymer of α-methylstyrene and styrene, etc.) because the effect of the present invention tends to be obtained better. Is preferable, and a copolymer of α-methylstyrene and styrene is more preferable.

The softening point of the styrenic resin is preferably 30 ° C. or higher, more preferably 60 ° C. or higher, and preferably 120 ° C. or lower, more preferably 85 ° C. or lower. Within the above range, the effects of the present invention tend to be obtained more favorably.
In the present invention, the softening point of the resin is the temperature at which the sphere descends when the softening point specified in JIS K 6220-1: 2001 is measured with a ring and ball softening point measuring device.

The number average molecular weight (Mn) of the styrene resin is preferably 500 or more, more preferably 700 or more, and preferably 3000 or less, more preferably 2000 or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

When the styrene resin is contained, the content of the styrene resin is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and further preferably 10 parts by mass or more, with respect to 100 parts by mass of the rubber component. Moreover, Preferably it is 70 mass parts or less, More preferably, it is 50 mass parts or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

The rubber composition may contain other resins in addition to the styrene resin. Other resins are not particularly limited as long as they are widely used in the tire industry. Rosin resins, coumarone indene resins, terpene resins, pt-butylphenol acetylene resins, acrylic resins, C5 resins, C9 resin etc. are mentioned. These may be used alone or in combination of two or more.

Examples of commercially available styrenic resins and other resins include Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yashara Chemical Co., Ltd., Tosoh Corp., Rutgers Chemicals, BASF, Arizona Chemical, Japan Products such as Nikko Kagaku Co., Ltd., Nippon Shokubai Co., Ltd., JX Energy Co., Ltd., Arakawa Chemical Industry Co., Ltd., Taoka Chemical Industry Co., Ltd. can be used.

The rubber composition preferably contains carbon black. Thereby, there exists a tendency for the effect of this invention to be acquired more favorably.
The carbon black is not particularly limited, and examples thereof 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.

Cetyl trimethyl ammonium bromide (CTAB) specific surface area of the carbon black, preferably 110m ² / g or more, more preferably 160 m ² / g or more, more preferably 170m ² / g or more, particularly preferably be 180 m ² / g or more Moreover, Preferably it is 250 m < ² > / g or less, More preferably, it is 200 m < ² > / g or less. Within the above range, the effects of the present invention tend to be obtained more favorably.
The CTAB specific surface area of carbon black is a value measured according to JIS K6217-3: 2001.

Nitrogen adsorption specific surface area _(N 2 SA) of carbon black is preferably 110m ² / g or more, more preferably 140 m ² / g or more, more preferably 177m ² / g or more, preferably 250 meters ² / g Hereinafter, it is more preferably 200 m ² / g or less. Within the above range, the effects of the present invention tend to be obtained more favorably.
The N ₂ SA of carbon black is a value measured according to JIS K6217-2: 2001.

The iodine adsorption amount (IA) of carbon black is preferably 110 mg / g or more, more preferably 170 mg / g or more, still more preferably 188 mg / g or more, and preferably 250 mg / g or less, more preferably 200 mg / g. g or less. Within the above range, the effects of the present invention tend to be obtained more favorably.
In addition, IA of carbon black is a value measured in accordance with JIS K6217-1: 2008.

Examples of carbon black include products such as Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Co., Ltd., Lion Co., Ltd., NS Can be used.

When carbon black is contained, the content of carbon black is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and preferably 20 parts by mass or less, with respect to 100 parts by mass of the rubber component. Preferably it is 15 mass parts or less. Within the above range, the effect of the present invention can be more suitably obtained.

The rubber composition may contain oil.
Examples of the oil include process oil, vegetable oil and fat, or a mixture thereof. As the process oil, for example, a paraffin process oil, an aroma process oil, a naphthene process oil, or the like can be used. As vegetable oils and fats, castor oil, cottonseed oil, sesame oil, rapeseed oil, soybean oil, palm oil, palm oil, peanut oil, rosin, pine oil, pineapple, tall oil, corn oil, rice bran oil, beet flower oil, sesame oil, Examples include olive oil, sunflower oil, palm kernel oil, camellia oil, jojoba oil, macadamia nut oil, and tung oil. These may be used alone or in combination of two or more. Among these, process oil is preferable and aroma-based process oil is more preferable because the effects of the present invention can be obtained satisfactorily.

When oil is contained, the oil content is preferably 1 part by mass or more, more preferably 10 parts by mass or more, and preferably 50 parts by mass or less, more preferably 100 parts by mass of the rubber component. It is 40 mass parts or less, More preferably, it is 35 mass parts or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

The rubber composition may contain a wax.
The wax is not particularly limited, and examples thereof include petroleum waxes such as paraffin wax and microcrystalline wax; natural waxes such as plant waxes and animal waxes; synthetic waxes such as polymers such as ethylene and propylene. These may be used alone or in combination of two or more. Of these, petroleum wax is preferable, and paraffin wax is more preferable.

As the wax, for example, products such as Ouchi Shinsei Chemical Co., Ltd., Nippon Seiwa Co., Ltd., Seiko Chemical Co., Ltd. can be used.

When the wax is contained, the content of the wax is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 20 parts by mass or less, more preferably 100 parts by mass of the rubber component. It is 10 parts by mass or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

The rubber composition may contain an anti-aging agent.
Examples of the antiaging agent include naphthylamine type antiaging agents such as phenyl-α-naphthylamine; diphenylamine type 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, etc. P-phenylenediamine-based antioxidants; quinoline-based antioxidants such as 2,2,4-trimethyl-1,2-dihydroquinoline polymer; 2,6-di-t-butyl-4-methylphenol; Monophenolic antioxidants such as styrenated phenol; tetrakis- [methylene-3- (3 ', 5'-di-t-butyl- '- hydroxyphenyl) propionate] bis methane, tris, polyphenolic antioxidants, and the like. These may be used alone or in combination of two or more. Of these, p-phenylenediamine-based antioxidants and quinoline-based antioxidants are preferable.

As the anti-aging agent, for example, products such as Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinsei Chemical Co., Ltd., and Flexis Co. can be used.

When the anti-aging agent is contained, the content of the anti-aging agent is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and preferably 10 parts by mass or less with respect to 100 parts by mass of the rubber component. More preferably, it is 8 parts by mass or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

The rubber composition may contain stearic acid.
A conventionally well-known thing can be used as a stearic acid, For example, products, such as NOF Corporation, NOF company, Kao Corporation, Wako Pure Chemical Industries, Ltd., and Chiba fatty acid company, can be used.

When stearic acid is contained, the content of stearic acid is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and preferably 10 parts by mass or less, with respect to 100 parts by mass of the rubber component. Preferably it is 5 mass parts or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

The rubber composition may contain zinc oxide.
Conventionally known zinc oxide can be used, for example, Mitsui Kinzoku Mining Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Shodo Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd. Can be used.

When zinc oxide is contained, the content of zinc oxide is preferably 1 part by mass or more, more preferably 2.5 parts by mass or more, and preferably 10 parts by mass or less with respect to 100 parts by mass of the rubber component. More preferably, it is 5 parts by mass or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

The rubber composition may contain sulfur.
Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, soluble sulfur and the like generally used in the rubber industry. These may be used alone or in combination of two or more.

As the sulfur, for example, products such as Tsurumi Chemical Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Kasei Kogyo Co., Ltd., Flexis Co., Nihon Kiboshi Kogyo Co., Ltd., Hosoi Chemical Co., Ltd. can be used.

When sulfur is contained, the content of sulfur is preferably 0.5 parts by mass or more, more preferably 2 parts by mass or more, and preferably 10 parts by mass or less, based on 100 parts by mass of the rubber component. Preferably it is 5 mass parts or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

The rubber composition may contain a vulcanization accelerator.
Examples of the vulcanization accelerator include thiazole vulcanization accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide, N-cyclohexyl-2-benzothiazylsulfenamide; tetramethylthiuram disulfide (TMTD ), Tetrabenzylthiuram disulfide (TBzTD), tetrakis (2-ethylhexyl) thiuram disulfide (TOT-N), and other thiuram vulcanization accelerators; N-cyclohexyl-2-benzothiazolesulfenamide, Nt-butyl- 2-benzothiazolylsulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, N, N′-diisopropyl-2-benzothiazole sulfenamide, etc. Sulfena De-based vulcanization accelerator; diphenylguanidine, may be mentioned di-ortho-tolyl guanidine, guanidine-based vulcanization accelerators such as ortho tri ruby guanidine. These may be used alone or in combination of two or more. Of these, sulfenamide-based vulcanization accelerators and guanidine-based vulcanization accelerators are preferred because the effects of the present invention can be obtained more suitably.

When the vulcanization accelerator is contained, the content of the vulcanization accelerator is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and preferably 10 parts by mass with respect to 100 parts by mass of the rubber component. Part or less, more preferably 8 parts by weight or less. Within the above range, the effects of the present invention tend to be obtained more favorably.

In addition to the above components, the rubber composition includes additives generally used in the tire industry, such as organic peroxides; fillers such as calcium carbonate, talc, alumina, clay, aluminum hydroxide, and mica. Etc. may be further blended. The content of these additives is preferably 0.1 to 200 parts by mass with respect to 100 parts by mass of the rubber component.

The rubber composition can be produced, for example, by a method of kneading the above components using a rubber kneading apparatus such as an open roll or a Banbury mixer, and then vulcanizing.

As kneading conditions, in the base kneading step in which additives other than the vulcanizing agent and the vulcanization accelerator are kneaded, the kneading temperature is usually 100 to 180 ° C, preferably 120 to 170 ° C. In the final kneading step of kneading the vulcanizing agent and vulcanization accelerator, the kneading temperature is usually 120 ° C. or lower, preferably 85 to 110 ° C. Further, a composition obtained by kneading a vulcanizing agent and a vulcanization accelerator is usually subjected to vulcanization treatment such as press vulcanization. The vulcanization temperature is usually 140 to 190 ° C, preferably 150 to 185 ° C. The vulcanization time is usually 5 to 15 minutes.

The rubber composition is suitably used for treads (cap treads), but for members other than treads, for example, sidewalls, base treads, under treads, clinch apex, bead apex, breaker cushion rubber, carcass cord coating It may be used for rubber, insulation, chafers, inner liners, etc., or side reinforcement layers for run-flat tires.

The pneumatic tire of the present invention is produced by a usual method using the rubber composition.
That is, the rubber composition is extruded in accordance with the shape of each tire member of the tread at an unvulcanized stage, and molded together with other tire members by a normal method on a tire molding machine. Form a vulcanized tire. The unvulcanized tire is heated and pressurized in a vulcanizer to obtain a tire.

The pneumatic tire can be used for passenger car tires, truck / bus tires, motorcycle tires, high performance tires, and the like, and is particularly suitable for passenger car tires.

The present invention will be specifically described based on examples, but the present invention is not limited to these examples.
The various chemicals used in the examples are described below.
SBR1: modified SBR synthesized in the following Production Example 1 (styrene content: 25% by mass, vinyl content: 60% by mass, Mw: 150,000)
SBR2: Modified SBR synthesized in the following Production Example 2 (styrene content: 40% by mass, vinyl content: 30% by mass, Mw: 900,000)
SBR3: Buna VSL 5228-2 manufactured by LANXESS (styrene content: 28 mass%, vinyl content: 52 mass%, containing 37.5 mass parts of oil with respect to 100 mass parts of rubber solid content)
SBR4: Buna VSL 2438-2 HM manufactured by LANXESS (styrene content: 38 mass%, vinyl content: 24 mass%, containing 37.5 mass parts of oil with respect to 100 mass parts of rubber solid content)
BR: N103 manufactured by Asahi Kasei Chemicals Corporation (cis content: 38% by mass)
NR: TSR20
Carbon black 1: prototype (CTAB: 180 m ² / g, N ₂ SA: 177 m ² / g, IA: 188 mg / g)
Carbon black 2: N220 manufactured by Mitsubishi Chemical Corporation (CTAB: 111 m ² / g, N ₂ SA: 111 m ² / g)
Silica 1: Ultrasil 9000GR manufactured by Evonik Degussa (N ₂ SA: 240 m ² / g)
Silica 2: Ultrasil VN3 (N ₂ SA: 167 m ² / g) manufactured by Evonik Degussa
Silane coupling agent 1: NXT (3-octanoylthiopropyltriethoxysilane) manufactured by Momentive
Silane coupling agent 2: Si266 (bis (3-triethoxysilylpropyl) disulfide) manufactured by Evonik Degussa
Silane coupling agent 3: NXT-Z45 manufactured by Momentive (copolymer of bond unit A and bond unit B (bond unit A: 55 mol%, bond unit B: 45 mol%))
Oil: VIVETEC500 (TDAE oil) manufactured by H & R
Styrene resin: Sylvatrax 4401 (α-methylstyrene resin (copolymer of α-methylstyrene and styrene), Mn: 700, softening point: 85 ° C.) manufactured by Arizona Chemical Co., Ltd.
Wax: Ozoace 0355 manufactured by Nippon Seiwa Co., Ltd.
Anti-aging agent 1: NOCRACK 6C (N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Anti-aging agent 2: Antigen FR manufactured by Sumitomo Chemical Co., Ltd. (A product obtained by purifying a reaction product of amine and ketone with no amine residue, quinoline-based anti-aging agent)
Stearic acid: Stearic acid “椿” manufactured by NOF Corporation
Zinc oxide: Zinc Hua No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Sulfur: Powdered sulfur vulcanization accelerator manufactured by Tsurumi Chemical Co., Ltd. 1: Noxeller CZ (N-cyclohexyl-2) manufactured by Ouchi Shinsei Chemical Co., Ltd. -Benzothiazolylsulfenamide)
Vulcanization accelerator 2: Noxeller D (1,3-diphenylguanidine) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

(Production Example 1)
A nitrogen-substituted autoclave reactor was charged with cyclohexane, tetrahydrofuran, styrene, and 1,3-butadiene. After adjusting the temperature of the reactor contents to 20 ° C., n-butyllithium was added to initiate polymerization. Polymerization was performed under adiabatic conditions, and the maximum temperature reached 85 ° C. When the polymerization conversion rate reached 99%, 1,3-butadiene was added, and after further polymerizing for 5 minutes, 3-diethylaminopropyltrimethoxysilane was added as a modifier to carry out the reaction. After completion of the polymerization reaction, 2,6-di-tert-butyl-p-cresol was added. Subsequently, the solvent was removed by steam stripping, and drying was performed with a hot roll adjusted to 110 ° C. to obtain SBR1.

(Production Example 2)
A nitrogen-substituted autoclave reactor was charged with cyclohexane, tetrahydrofuran, styrene, and 1,3-butadiene. After adjusting the temperature of the reactor contents to 20 ° C., n-butyllithium was added to initiate polymerization. Polymerization was performed under adiabatic conditions, and the maximum temperature reached 85 ° C. When the polymerization conversion rate reached 99%, 1,3-butadiene was added, and after further polymerizing for 5 minutes, N, N-bis (trimethylsilyl) -3-aminopropyltriethoxysilane was added as a modifier. Reaction was performed. After completion of the polymerization reaction, 2,6-di-tert-butyl-p-cresol was added. Subsequently, the solvent was removed by steam stripping, and drying was performed with a hot roll adjusted to 110 ° C. to obtain SBR2.

(Analysis of SBR)
The structural identification of SBR (measurement of styrene content and vinyl content) was performed using a JNM-ECA series apparatus manufactured by JEOL Ltd. The measurement was performed after drying under reduced pressure, by dissolving 0.1 g of the polymer in 15 ml of toluene, slowly pouring it into 30 ml of methanol and reprecipitating it.

(Examples and Comparative Examples)
In accordance with the formulation shown in Table 1, materials other than sulfur and a vulcanization accelerator were kneaded for 5 minutes at 150 ° C. using a 1.7 L Banbury mixer manufactured by Kobe Steel, Ltd. Obtained. Next, sulfur and a vulcanization accelerator were added to the obtained kneaded product, and kneaded for 5 minutes under the condition of 80 ° C. using an open roll to obtain an unvulcanized rubber composition. The obtained unvulcanized rubber composition is formed into a tread shape and bonded together with other tire members to form an unvulcanized tire, press vulcanized at 150 ° C. for 12 minutes, and a test tire ( Size: 195 / 65R15). The following evaluation was performed using the obtained test tire, and the results are shown in Table 1.
In Table 1, the rubber content in the oil-extended rubber is described in the rubber column, and the oil content in the oil-extended rubber is added to the oil column.

(Low fuel consumption)
Using a rolling resistance tester, the rolling resistance when each test tire was run at a rim (15 × 6JJ), internal pressure (230 kPa), load (3.43 kN), speed (80 km / h) was measured, The index is shown as an index when the comparative example 2 is set to 100 (low fuel consumption index). A larger index indicates better fuel efficiency. In this embodiment, the target is set to 145 or more.

(Abrasion resistance)
Install each test tire on all wheels of a vehicle (domestic FF2000cc), measure the groove depth of the tire tread after a running distance of 8000km, calculate the running distance when the tire groove depth decreases by 1mm, and compare The results are shown as an index when Example 2 is set to 100 (wear resistance index). The larger the index, the longer the travel distance when the tire groove depth is reduced by 1 mm, and the better the wear resistance. In this embodiment, the target is 60 or more.

(Dry grip performance)
Each test tire was mounted on all wheels of a vehicle (domestic FF2000cc), and the vehicle traveled 10 laps on a dry asphalt road test course. The test place was Okayama test course of Sumitomo Rubber Industries, Ltd., and the temperature was 20-25 ° C. And the test driver evaluated the stability of the control at the time of steering in that case, and displayed it by the index when the comparative example 2 was set to 100 (dry grip performance index). The larger the index, the better the grip performance on the dry road surface. In this embodiment, the target is 70 or more.

Claims (7)

Rubber components including styrene butadiene rubber, butadiene rubber and isoprene-based rubber;
The content of silica with respect to 100 parts by mass of the rubber component is 70 parts by mass or more,
The styrene butadiene rubber is composed of a plurality of styrene butadiene rubbers,
The plurality of styrene butadiene rubbers are tire rubber compositions in which the difference in vinyl amount between each is 25% by mass or more. The rubber composition for a tire according to claim 1, wherein a content of the isoprene-based rubber is 10% by mass or more in 100% by mass of the rubber component. The rubber composition for tires according to claim 1 or 2, wherein the content of low cis butadiene rubber having a cis content of 50% by mass or less is 10% by mass or more in 100% by mass of the rubber component. The rubber composition for tires according to any one of claims 1 to 3 containing a styrene resin. The tire rubber composition according to any one of claims 1 to 4, comprising a mercapto-based silane coupling agent. The tire rubber composition according to claim 1, wherein the silica has a nitrogen adsorption specific surface area of 220 m ² / g or more. The pneumatic tire produced using the rubber composition in any one of Claims 1-6.