JP2018095701A - Rubber composition and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition that has fuel economy, wet grip performance and wear resistance improved in a balanced manner, and a pneumatic tire prepared with the rubber composition.SOLUTION: This invention relates to a tire rubber composition containing styrene-butadiene rubber A with a styrene content of 30-40 mass% and a vinyl content of 45-55 mass%, styrene-butadiene rubber B with a styrene content of 3-15 mass% and a vinyl content of 35-45 mass%, and silica.SELECTED DRAWING: None

Description

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

In recent years, due to increasing interest in environmental issues, there has been a strong demand for lower fuel consumption for automobiles, and rubber compositions used for automobile tires are also required to have excellent fuel efficiency. .

As a method for improving fuel economy, for example, a method of reducing the amount of reinforcing filler is known. However, in this method, wet grip performance and wear resistance are reduced due to a decrease in heat generation amount and reinforcing property of the rubber composition. Tended to get worse. As described above, these performances are generally in contradiction with low fuel consumption, and it has been difficult to obtain each performance in a well-balanced manner.

An object of the present invention is to solve the above-mentioned problems and to provide a rubber composition having improved fuel economy, wet grip performance and wear resistance in a balanced manner, and a pneumatic tire produced using the rubber composition. To do.

The present invention includes a rubber component having a styrene butadiene rubber content of 80% by mass or more, and 40 to 80 parts by mass of silica with respect to 100 parts by mass of the rubber component,
In 100% by mass of the styrene butadiene rubber, the content of styrene butadiene rubber A having a styrene content of 30 to 40% by mass and a vinyl content of 45 to 55% by mass is 50 to 75% by mass, the styrene content is 3 to 15% by mass, and the vinyl content is 35. It is related with the rubber composition for tires whose content of -45 mass% styrene butadiene rubber B is 20-40 mass%.

The total content of aluminum hydroxide and aluminum oxide is preferably 5 to 15 parts by mass with respect to 100 parts by mass of the rubber component.

The silica in 100% by mass, the content of nitrogen adsorption specific surface area 150 to 200 m ² / g of silica (1) is 50 to 75 mass%, the nitrogen adsorption specific surface area 90~120m ² / g of silica (2) Is preferably 20 to 40% by mass.

It is preferable that the content of the styrene butadiene rubber A and silica (1) with respect to 100 parts by mass of the rubber component satisfy the following formula.
0.8 ≦ styrene butadiene rubber A content / silica (1) content ≦ 2.0

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

According to the present invention, since it is a rubber composition containing a predetermined amount of styrene butadiene rubber A, styrene butadiene rubber B, and silica, low fuel consumption, wet grip performance, and wear resistance can be improved in a well-balanced manner.

The tire rubber composition of the present invention includes a rubber component having a styrene butadiene rubber content of 80% by mass or more, and 40 to 80 parts by mass of silica with respect to 100 parts by mass of the rubber component. In 100% by mass of rubber, the content of styrene butadiene rubber A having a styrene amount of 30 to 40% by mass and a vinyl amount of 45 to 55% by mass is 50 to 75% by mass, a styrene amount of 3 to 15% by mass and a vinyl amount of 35 to 45% by mass. % Of styrene butadiene rubber B is 20 to 40% by mass.

The reason why the rubber composition of the present invention has the above-described effect is presumed as follows.
In order to obtain excellent wet grip performance, when a styrene butadiene rubber (SBR A) having a high styrene content and a high vinyl content is used, problems such as low fuel consumption and wear resistance may occur. It became clear as a result of examination. On the other hand, the rubber composition of the present invention further blends low styrene content styrene butadiene rubber (SBR B) and silica, which balances fuel efficiency, wet grip performance and wear resistance. It can be improved well.
Furthermore, by using aluminum hydroxide and two types of silicas (1) and (2) having different specific surface areas, and adjusting the contents of SBR A and silica (1) having a high specific surface area, Fuel economy, wet grip performance and wear resistance can be improved in a better balance.

The rubber composition of the present invention contains styrene butadiene rubber (SBR) as a rubber component.
As SBR, styrene butadiene rubber A (SBR A) having a styrene content of 30 to 40% by mass and a vinyl content of 45 to 55% by mass, and a styrene butadiene rubber B having a styrene content of 3 to 15% by mass and a vinyl content of 35 to 45% by mass. (SBR B). In addition to SBR A and SBR B, SBR other than SBR A and SBR B may be used as SBR.

SBR such as SBR A and SBR B is not particularly limited, and for example, emulsion polymerization styrene butadiene rubber (E-SBR), solution polymerization styrene butadiene rubber (S-SBR), and the like can be used.

The amount of styrene in SBR A is 30% by mass or more, preferably 33% by mass or more. When the styrene content is 30% by mass or more, good wet grip performance can be obtained. The amount of styrene is 40% by mass or less, preferably 37% by mass or less. When the amount of styrene is 40% by mass or less, heat generation is reduced and good fuel efficiency is obtained.
In the present specification, the amount of styrene is calculated by H ¹ -NMR measurement.

The vinyl content of SBR A is 45% by mass or more, preferably 48% by mass or more. When the vinyl content is 45% by mass or more, good wet grip performance can be obtained. The vinyl content is 55% by mass or less, preferably 51% by mass or less. When the vinyl content is 55% by mass or less, good wear resistance can be obtained.
In the present specification, the vinyl content (1,2-bond butadiene unit content) can be measured by infrared absorption spectrum analysis.

The amount of styrene in SBR B is 3% by mass or more, preferably 7% by mass or more. When the styrene content is 3% by mass or more, good wet grip performance can be obtained. The amount of styrene is 15% by mass or less, preferably 11% by mass or less. When the amount of styrene is 15% by mass or less, heat generation is reduced, good fuel economy is obtained, and good wear resistance is obtained.

The vinyl content of SBR B is 35% by mass or more, preferably 39% by mass or more. When the vinyl content is 35% by mass or more, good wet grip performance can be obtained. The vinyl content is 45% by mass or less, preferably 42% by mass or less. When the vinyl content is 45% by mass or less, good wear resistance can be obtained.

SBR A may be non-modified SBR or modified SBR, but modified SBR (modified SBR A) is preferable because the effects of the present invention can be obtained more satisfactorily.
The modified SBR A 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). Modified SBR (terminal modified SBR having the above functional group at the terminal), main chain modified SBR having the above functional group at the main chain, and main chain terminal modified SBR having the above functional group at the main chain and terminal (for example, main chain) Modified with a polyfunctional compound having two or more epoxy groups in the molecule, having at least one terminal modified with the above-mentioned functional group, and at least one terminal modified with the above-mentioned modifier. Examples thereof include terminal-modified SBR introduced with a hydroxyl group or an epoxy group. By using such a modified SBR as the modified SBR A, the fuel economy, wet grip performance, and wear resistance are improved.

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, because the effects of the present invention can be obtained more suitably. C1-C6 alkoxy group) and alkoxysilyl groups (preferably C1-C6 alkoxysilyl groups) are preferred.

（式（１）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 A, SBR modified with a compound (modifier) represented by the following formula (1) is preferable.

(In the formula (1), R ¹ , R ² and R ³ are the same or different and are alkyl group, alkoxy group, silyloxy group, acetal group, carboxyl group (—COOH), mercapto group (—SH) or these R ⁴ and R ⁵ are 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 (1) (modifier), the polymerization terminal (active terminal) of the solution-polymerized styrene butadiene rubber (S-SBR) is the above formula (1). A styrene butadiene rubber modified with a compound represented by the formula (modified SBR described in JP 2010-111753 A) is preferably used.

In the above formula (1), an alkoxy group is preferable as R ¹ , R ^2, and R ^{3 in} terms of obtaining excellent fuel economy, fracture characteristics, and abrasion resistance (preferably having 1 to 8 carbon atoms). , More preferably an alkoxy group 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 compound represented by the above formula (1) include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, and 3-dimethylaminopropyltriethoxy. Examples include silane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, and 3-diethylaminopropyltriethoxysilane. Of these, 3-dimethylaminopropyltrimethoxysilane, 3-dimethylaminopropyltriethoxysilane, and 3-diethylaminopropyltrimethoxysilane are preferable because the above-described performance can be improved satisfactorily. These may be used alone or in combination of two or more.

SBR B may be non-modified SBR or modified SBR, but modified SBR (modified SBR B) is preferable because the effects of the present invention can be obtained more satisfactorily. Examples of the modified SBR B include the same modified SBR as the modified SBR described for the modified SBR A.

The modified SBR B is preferably a modified SBR modified with the following compound (group). Examples of the compound (group) include polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether, glycerin triglycidyl ether, trimethylol ethane triglycidyl ether, trimethylol propane triglycidyl ether; 2 such as diglycidylated bisphenol A Polyglycidyl ethers of aromatic compounds having one or more phenol groups; polyepoxy compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, polyepoxidized liquid polybutadiene; 4,4′-diglycidyl -Epoxy group-containing tertiary amines such as diphenylmethylamine and 4,4'-diglycidyl-dibenzylmethylamine; diglycidylaniline, N, N'-diglycidyl-4-glycidyloxyaniline, diglycyl Jill ortho 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-morpholine carbonyl chloride, 1-pyrrolidine carbonyl 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; alkoxysilanes such as methyltriethoxysilane; 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, N ′, N ′ A (thio) benzophenone compound having an amino group and / or a substituted amino group such as bis- (tetraethylamino) benzophenone; 4-N, N-dimethylaminobenzaldehyde, 4-N, N-diphenylaminobenzaldehyde, 4-N, Amino groups such as N-divinylaminobenzaldehyde And / or a benzaldehyde compound having a substituted amino group; N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, Nt-butyl-2-pyrrolidone, N-methyl-5 N-substituted pyrrolidones such as methyl-2-pyrrolidone N-substituted piperidones such as N-methyl-2-piperidone, N-vinyl-2-piperidone, N-phenyl-2-piperidone; N-methyl-ε-caprolactam; N such as N-phenyl-ε-caprolactam, N-methyl-ω-laurylactam, N-vinyl-ω-laurylactam, N-methyl-β-propiolactam, N-phenyl-β-propiolactam, etc. -Substituted lactams;

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. Among these, modified SBR modified with alkoxysilane is preferable because the effects of the present invention can be obtained better.
In addition, modification | denaturation by the said compound can be performed by a well-known method.

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

The content of SBR in 100% by mass of the rubber component (preferably, the total content of SBR A and SBR B) is 80% by mass or more. The effect of this invention is fully acquired as it is 80 mass% or more. The content may be 100% by mass, but is preferably 95% by mass or less. There exists a tendency for the effect of this invention to be acquired more favorably that it is 95 mass% or less.

The content of SBR A in 100% by mass of the rubber component is preferably 40% by mass or more, more preferably 50% by mass or more. There exists a tendency for wet grip performance to be acquired more favorably as it is 40 mass% or more. The content is preferably 80% by mass or less, more preferably 70% by mass or less. When the content is 80% by mass or less, low fuel consumption and wear resistance tend to be obtained more favorably.

The content of SBR B in 100% by mass of the rubber component is preferably 10% by mass or more, more preferably 20% by mass or more. When it is 10% by mass or more, low fuel consumption and wear resistance tend to be obtained better. The content is preferably 50% by mass or less, more preferably 40% by mass or less. There exists a tendency for wet grip performance to be more favorably obtained as it is 50 mass% or less.

The content of SBR A in 100% by mass of SBR is 50% by mass or more, preferably 60% by mass or more. Good wet grip performance is obtained as it is 50 mass% or more. The content is 75% by mass or less, preferably 70% by mass or less. When it is 75% by mass or less, good fuel economy and wear resistance can be obtained.

The content of SBR B in 100% by mass of SBR is 20% by mass or more, preferably 25% by mass or more. When it is 20% by mass or more, good fuel efficiency and wear resistance can be obtained. The content is 40% by mass or less. Good wet grip performance is obtained as it is 40 mass% or less.

The total content of SBR A and SBR B in 100% by mass of SBR is preferably 80% by mass or more, more preferably 90% by mass or more, and may be 100% by mass. There exists a tendency for the effect of this invention to be acquired more favorably that it is 80 mass% or more.

In addition to SBR such as SBR A and SBR B, rubber components that can be used in the present invention include isoprene-based rubber, butadiene rubber (BR), acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR), styrene- Examples thereof include diene rubbers such as isoprene-butadiene copolymer rubber (SIBR). These diene rubbers may be used alone or in combination of two or more. Of these, isoprene-based rubber and BR are preferable, and BR is more preferable because the wear resistance and fuel efficiency can be further improved.

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 isoprene-based rubber in 100% by mass of the rubber component is preferably 20% by mass or less. If it is within the above numerical range, the effect of the present invention tends to be obtained better.

The BR is not particularly limited. For example, BR1220 manufactured by ZEON Corporation, BR130B manufactured by Ube Industries, Ltd. BR containing tactic polybutadiene crystals can be used. These may be used alone or in combination of two or more. In particular, the cis content of BR is preferably 95% by mass or more from the reason that the wear resistance is improved.
The BR may be non-modified BR or modified BR. Examples of the modified BR include modified BR in which a functional group similar to modified SBR A and modified SBR B is introduced.

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

The content of BR in 100% by mass of the rubber component is preferably 3% by mass or more, more preferably 5% by mass or more. When it is 3% by mass or more, wear resistance tends to be obtained more favorably. The BR content is preferably 20% by mass or less. When the content is 20% by mass or less, the content of SBR A and SBR B is secured without lowering, and the effects of the present invention tend to be obtained more favorably.

The rubber composition of the present invention contains silica.
The silica, the nitrogen adsorption specific surface area 150 to 200 m ² / g of silica (1), preferably contains a nitrogen adsorption specific surface area 90~120m ² / g of silica (2). Further, as silica, silica other than silica (1) and (2) may be used in addition to silica (1) and (2).

Examples of silicas such as silica (1) and (2) include dry process silica (anhydrous silica), wet process silica (hydrous silica), and wet process silica is preferred because of its large number of silanol groups.

The nitrogen adsorption specific surface area (N ₂ SA) of silica (1) is preferably 150 m ² / g or more, more preferably 170 m ² / g or more. When it is 150 m ₂ / g or more, better wear resistance is obtained. The N ₂ SA is preferably 200 m ² / g or less, more preferably 180 m ² / g or less. When it is 200 m ² / g or less, better fuel efficiency can be obtained.
The nitrogen adsorption specific surface area of silica is a value measured by the BET method according to ASTM D3037-81.

The nitrogen adsorption specific surface area (N ₂ SA) of silica (2) is preferably 90 m ² / g or more, more preferably 110 m ² / g or more. When it is 90 m ² / g or more, better wear resistance is obtained. The N ₂ SA is preferably 120 m ² / g or less. The effect acquired by mixing with a silica (1) becomes it larger that it is 120 m < ² > / g or less.

Examples of silicas such as silica (1) and (2) include products such as Degussa, Rhodia, Tosoh Silica, Solvay Japan, and Tokuyama.

The content of silica (preferably the total content of silica (1) and (2)) is 40 parts by mass or more, preferably 60 parts by mass or more with respect to 100 parts by mass of the rubber component. The effect of this invention is fully acquired as it is 40 mass parts or more. Moreover, the said content is 80 mass parts or less. When it is 80 parts by mass or less, it becomes easy for silica to be uniformly dispersed in the rubber composition, and good fuel economy and wear resistance can be obtained.

The content of silica (1) is preferably 20 parts by mass or more, more preferably 30 parts by mass or more with respect to 100 parts by mass of the rubber component. There exists a tendency for low-fuel-consumption property to be acquired more favorably as it is 20 mass parts or more. The content is preferably 70 parts by mass or less, more preferably 60 parts by mass or less. There exists a tendency for low-fuel-consumption property to be acquired more favorably as it is 70 mass parts or less.

The content of silica (2) is preferably 5 parts by mass or more, more preferably 10 parts by mass or more with respect to 100 parts by mass of the rubber component. When the amount is 5 parts by mass or more, the wear resistance tends to be more favorably obtained. Further, the content is preferably 40 parts by mass or less, more preferably 30 parts by mass or less. There exists a tendency for workability to be obtained more favorable in it being 40 mass parts or less.

In 100% by mass of silica, the content of silica (1) is preferably 50% by mass or more, more preferably 60% by mass or more. When the content is 50% by mass or more, better fuel efficiency can be obtained. The content is preferably 75% by mass or less, more preferably 70% by mass or less. When the content is 75% by mass or less, better fuel efficiency can be obtained.

In 100% by mass of silica, the content of silica (2) is preferably 20% by mass or more, more preferably 25% by mass or more. When it is 20% by mass or more, better wear resistance can be obtained. The content is preferably 40% by mass or less. When it is 40% by mass or less, better workability can be obtained.

In 100% by mass of silica, the total content of silica (1) and (2) is preferably 80% by mass or more, more preferably 90% by mass or more, and may be 100% by mass. There exists a tendency for the effect of this invention to be acquired more favorably that it is 80 mass% or more.

In the rubber composition of the present invention, the content of SBR A and silica (1) with respect to 100 parts by mass of the rubber component preferably satisfies the following formula. Thereby, low fuel consumption, wet grip performance, and wear resistance can be improved in a more balanced manner. The lower limit is more preferably 0.9. On the other hand, the upper limit is more preferably 1.9, and still more preferably 1.6.
0.8 ≦ styrene butadiene rubber A content / silica (1) content ≦ 2.0

The rubber composition of the present invention preferably contains aluminum hydroxide and / or aluminum oxide. It does not specifically limit as aluminum hydroxide or aluminum oxide, A thing common in a tire industry can be used.
Aluminum hydroxide may be partly or wholly converted to aluminum oxide during kneading or the like, but the aluminum oxide contained in the rubber composition of the present invention may be one obtained by converting aluminum hydroxide. Further, it may be blended separately from aluminum hydroxide.

The nitrogen adsorption specific surface area (BET specific surface area, N ₂ SA) of aluminum hydroxide and / or aluminum oxide is preferably 6.0 m ² / g or more, more preferably 10 m ² / g or more, from the viewpoint of wet grip performance. Further, the nitrogen adsorption specific surface area, the dispersibility of the aluminum hydroxide or aluminum oxide, re aggregation preventing, from the viewpoint of abrasion resistance, is preferably from ^{60 m} 2 / g, more preferably not more than ^40m 2 / g, ^20m 2 / More preferably, it is g or less.
In addition, the nitrogen adsorption specific surface area of aluminum hydroxide and aluminum oxide is a value measured by the BET method according to ASTM D3037-81.

The average particle diameter (D50) of aluminum hydroxide and / or aluminum oxide is preferably 0.1 μm or more, and preferably 0.3 μm or more from the viewpoints of dispersibility of aluminum hydroxide and aluminum oxide, prevention of reaggregation, and wear resistance. More preferred. The average particle diameter is preferably 3 μm or less, more preferably 1 μm or less from the viewpoint of wear resistance.
In addition, the average particle diameter (D50) of aluminum hydroxide and aluminum oxide is a particle diameter with an integrated mass value of 50% of a particle diameter distribution curve obtained by a particle diameter distribution measuring apparatus.

As aluminum hydroxide, products, such as Sumitomo Chemical Co., Ltd., Showa Denko Co., Ltd., Nabaltec, etc., can be used, for example. Examples of aluminum oxide that can be used include products such as Sumitomo Chemical Co., Ltd., Showa Denko Co., Ltd., Nippon Light Metal Co., Ltd., and Nippon Steel & Sumikin Materials Co., Ltd.

The total content of aluminum hydroxide and aluminum oxide is preferably 5 to 15 parts by mass with respect to 100 parts by mass of the rubber component. Within the above numerical range, the effects of the present invention can be obtained more sufficiently.

The rubber composition of the present invention preferably contains a silane coupling agent together with silica.
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 -Sulphides such as triethoxysilylpropyl methacrylate monosulfide, 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, Momentive NXT, NXT-Z, etc. mercapto, vinyltriethoxysilane, vinyl Vinyl type such as trimethoxysilane, amino type such as 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycid Glycidoxy such as cyclopropyltrimethoxysilane, nitro such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane, chloro such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane Etc. 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 preferable because the effects of the present invention can be obtained better.

（式（２）中、ｐは１〜３の整数、ｑは１〜５の整数、ｋは５〜１２の整数である。） As the silane coupling agent, it is preferable to use a silane coupling agent represented by the formula (2). Thereby, there exists a tendency for the outstanding low fuel consumption and wet grip performance to be acquired.

(In Formula (2), p is an integer of 1-3, q is an integer of 1-5, k is an integer of 5-12.)

In the formula (2), p is an integer of 1 to 3, but 2 is preferable. When p is 3 or less, the coupling reaction tends to be fast.
Although q is an integer of 1-5, 2-4 are preferable and 3 is more preferable. When q is 1 to 5, the synthesis tends to be easy.
k is an integer of 5 to 12, preferably 5 to 10, more preferably 6 to 8, and still more preferably 7.

Examples of the silane coupling agent represented by the formula (2) include 3-octanoylthio-1-propyltriethoxysilane.

Examples of the silane coupling agent that can be used include Degussa, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Amax Co., Ltd., and Toray Dow Corning Co., Ltd.

3 mass parts or more are preferable with respect to 100 mass parts of silica, and, as for content of a silane coupling agent, 5 mass parts or more are more preferable. There exists a tendency for the effect by having mix | blended the silane coupling agent as it is 3 mass parts or more to be acquired. The content is preferably 20 parts by mass or less, and more preferably 15 parts by mass or less. When the amount is 20 parts by mass or less, an effect commensurate with the blending amount is obtained, and good workability during kneading tends to be obtained.

The rubber composition of the present invention preferably contains carbon black.
Although it does not specifically limit as carbon black, N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762 etc. are mentioned. These may be used alone or in combination of two or more.

Nitrogen adsorption specific surface area _(N 2 SA) of carbon black is preferably at least ^{5 m} 2 / g, more preferably not less than ^{50m 2 / g, 100m 2 /} g or more is particularly preferable. When it is 5 m ² / g or more, the reinforcing property is improved and sufficient wear resistance tends to be obtained. Further, the _N 2 SA is preferably 200 meters ² / g or less, more preferably 150 meters ² / g, more preferably not more than 130m ² / g. When it is 200 m ² / g or less, good dispersion of carbon black tends to be obtained, and good wear resistance and low fuel consumption tend to be obtained.
In addition, the nitrogen adsorption specific surface area of carbon black is calculated | required by JISK6217-2: 2001.

Carbon black has a dibutyl phthalate oil absorption (DBP) of preferably 5 ml / 100 g or more, more preferably 50 ml / 100 g or more, and still more preferably 100 ml / 100 g or more. When it is 5 ml / 100 g or more, the reinforcing property is improved and sufficient wear resistance tends to be obtained. The DBP is preferably 300 ml / 100 g or less, more preferably 200 ml / 100 g or less, still more preferably 130 ml / 100 g or less. There exists a tendency for favorable abrasion resistance to be acquired as it is 300 ml / 100g or less.
In addition, DBP of carbon black is calculated | required by the measuring method of JISK6217-4: 2001.

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., Shin-Nikka Carbon Co., Ltd., Columbia Carbon Co., etc. Can be used.

The content of carbon black is preferably 1 part by mass or more, more preferably 3 parts by mass or more with respect to 100 parts by mass of the rubber component. When the amount is 1 part by mass or more, sufficient reinforcement can be obtained, and good wear resistance tends to be obtained. The content is preferably 30 parts by mass or less, more preferably 15 parts by mass or less. There exists a tendency for favorable rolling resistance to be acquired as it is 30 mass parts or less.

The total content of silica, aluminum hydroxide, aluminum oxide and carbon black is preferably 20 to 150 parts by mass, more preferably 100 parts by mass with respect to 100 parts by mass of the rubber component, because the effects of the present invention can be obtained better. Is 40 to 120 parts by mass, more preferably 60 to 100 parts by mass.

The rubber composition of the present invention preferably contains 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 naphthenic process oil, or the like can be used. Vegetable oils include castor oil, cottonseed oil, sesame oil, rapeseed oil, soybean oil, palm oil, palm oil, peanut hot water, 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, naphthenic process oils are preferable because the effects of the present invention can be obtained better.

Examples of the oil include Idemitsu Kosan Co., Ltd., Sankyo Oil Chemical Co., Ltd., Japan Energy Co., Ltd., Orisoi Co., Ltd., H & R Co., Toyokuni Oil Co., Ltd., Showa Shell Sekiyu Co., Ltd., Fuji Kosan Co., Ltd. Etc. can be used.

The oil content is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and still more preferably 10 parts by mass or more with respect to 100 parts by mass of the rubber component. Further, the content is preferably 50 parts by mass or less, more preferably 30 parts by mass or less. If it is within the above numerical range, the effect of the present invention tends to be obtained better.
The oil content includes the amount of oil contained in rubber (oil-extended rubber).

The rubber composition of the present invention preferably contains a resin.
The resin is not particularly limited as long as it is generally used in the tire industry. For example, coumarone indene resin, α-methylstyrene resin, terpene resin, pt-butylphenol acetylene resin, acrylic Based resins and the like. These may be used alone or in combination of two or more. Of these, α-methylstyrene-based resins are preferred because the effects of the present invention can be obtained more favorably.

Coumarone indene resin is a resin containing coumarone and indene as a monomer component constituting the resin skeleton (main chain), and monomer components contained in the skeleton other than coumarone and indene include styrene, α-methylstyrene, Examples thereof include methylindene and vinyltoluene.

Examples of the α-methylstyrene-based resin include α-methylstyrene homopolymer, a copolymer of α-methylstyrene and styrene, and the like.

Examples of the terpene resin include polyterpene, terpene phenol, and aromatic modified terpene resin.
Polyterpenes are resins obtained by polymerizing terpene compounds and their hydrogenated products. The terpene compound is a hydrocarbon represented by a composition of (C ₅ H ₈ ) _n and an oxygen-containing derivative thereof. Monoterpene (C ₁₀ H ₁₆ ), sesquiterpene (C ₁₅ H ₂₄ ), diterpene (C ₂₀ H ₃₂₎ Terpenes having a basic skeleton classified into, for example, α-pinene, β-pinene, dipentene, limonene, myrcene, alloocimene, ocimene, α-ferrandrene, α-terpinene, γ-terpinene, terpinolene 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, γ-terpineol and the like.

Examples of polyterpenes include terpene resins such as α-pinene resins, β-pinene resins, limonene resins, dipentene resins, β-pinene / limonene resins, etc., which are made from the above-mentioned terpene compounds, as well as hydrogenated terpene resins. Additive terpene resins are also included.
Examples of the terpene phenol include a resin obtained by copolymerizing the terpene compound and the phenol compound, and a resin obtained by hydrogenating the resin. Specifically, the terpene compound, the phenol compound, and formalin are condensed. Resin. Examples of phenolic compounds include phenol, bisphenol A, cresol, and xylenol.
Examples of the aromatic modified terpene resin include a resin obtained by modifying a terpene resin with an aromatic compound, and a resin obtained by hydrogenating the resin. The aromatic compound is not particularly limited as long as it has an aromatic ring. For example, phenol compounds such as phenol, alkylphenol, alkoxyphenol, unsaturated hydrocarbon group-containing phenol; naphthol, alkylnaphthol, alkoxynaphthol, Examples thereof include naphthol compounds such as unsaturated hydrocarbon group-containing naphthol; styrene derivatives such as styrene, alkylstyrene, alkoxystyrene, and unsaturated hydrocarbon group-containing styrene; coumarone and indene.

Examples of the pt-butylphenol acetylene resin include a resin obtained by a condensation reaction of pt-butylphenol and acetylene.

The acrylic resin is not particularly limited, but a solventless acrylic resin can be suitably used in that it can be made into a resin with few impurities and a sharp molecular weight distribution, and the effects of the present invention can be obtained better.

Solvent-free acrylic resin is a high-temperature continuous polymerization method (high-temperature continuous mass polymerization method) (U.S. Pat. No. 4,414,370) without using polymerization initiators, chain transfer agents, organic solvents and the like as auxiliary materials as much as possible. Description, Japanese Patent Application Laid-Open No. 59-6207, Japanese Patent Publication No. 5-58005, Japanese Patent Application Laid-Open No. 1-313522, US Pat. No. 5,010,166, Toa Gosei Research Annual Report TREND 2000 No. 3 p42- (Meth) acrylic resin (polymer) synthesized by the method described in 45 et al. In the present invention, (meth) acryl means methacryl and acryl.

It is preferable that the acrylic resin does not substantially contain a polymerization initiator, a chain transfer agent, an organic solvent, or the like, which are auxiliary materials. Moreover, the said acrylic resin has a comparatively narrow composition distribution and molecular weight distribution obtained by continuous polymerization at the point of the effect of this invention.

As described above, the acrylic resin is preferably one that does not substantially contain a polymerization initiator, a chain transfer agent, an organic solvent, or the like that is a secondary raw material, that is, has a high purity. The purity of the acrylic resin (ratio of the resin contained in the resin) is preferably 95% by mass or more, more preferably 97% by mass or more.

Examples of the monomer component constituting the acrylic resin include (meth) acrylic acid, (meth) acrylic acid esters (alkyl esters, aryl esters, aralkyl esters, etc.), (meth) acrylamides, and (meth) acrylamide derivatives. And (meth) acrylic acid derivatives.

Moreover, as monomer components constituting the acrylic resin, together with (meth) acrylic acid and (meth) acrylic acid derivatives, styrene, α-methylstyrene, vinyl toluene, vinyl naphthalene, divinyl benzene, trivinyl benzene, divinyl naphthalene, etc. Aromatic vinyl may be used.

The acrylic resin may be a resin composed only of a (meth) acrylic component, or may be a resin including components other than the (meth) acrylic component.
The acrylic resin may have a hydroxyl group, a carboxyl group, a silanol group, or the like.

The softening point of the resin is preferably 30 ° C or higher, more preferably 60 ° C or higher, and still more preferably 80 ° C or higher. There exists a tendency for desired wet grip performance to be acquired as it is 30 ° C or more. The softening point is preferably 160 ° C. or lower, more preferably 130 ° C. or lower, and still more preferably 100 ° C. or lower. When the temperature is 160 ° C. or lower, the dispersibility of the resin becomes good, and the wet grip performance and the low fuel consumption tend to be improved.
In the present invention, the softening point of the resin is a temperature at which the sphere descends when the softening point defined in JIS K 6220-1: 2001 is measured with a ring and ball softening point measuring apparatus.

Examples of the resin include Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yashara Chemical Co., Ltd., Tosoh Co., Ltd., Rutgers Chemicals Co., Ltd., BASF Co., Arizona Chemical Co., Ltd. Products such as Nippon Shokubai, JX Energy Co., Ltd., Arakawa Chemical Co., Ltd., Taoka Chemical Co., Ltd. can be used.

The content of the resin is preferably 1 part by mass or more, more preferably 3 parts by mass or more with respect to 100 parts by mass of the rubber component. The content is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and still more preferably 15 parts by mass or less. Within the above numerical range, the effects of the present invention tend to be obtained satisfactorily.

The rubber composition of the present invention preferably contains 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 waxes are preferred and paraffin waxes are more preferred because the effects of the present invention can be obtained better.

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

The content of the wax is preferably 1 part by mass or more, more preferably 2 parts by mass or more with respect to 100 parts by mass of the rubber component. Moreover, the content is preferably 20 parts by mass or less, more preferably 10 parts by mass or less. Within the above numerical range, the effects of the present invention tend to be obtained satisfactorily.

The rubber composition of the present invention preferably contains an antiaging 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, and the like polyphenolic antioxidants. These may be used alone or in combination of two or more. Of these, p-phenylenediamine-based antioxidants and quinoline-based antioxidants are preferable, and N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine, 2,2,4-trimethyl-1 More preferred is a polymer of 1,2-dihydroquinoline.

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.

The content of the anti-aging agent is preferably 1 part by mass or more, more preferably 3 parts by mass or more with respect to 100 parts by mass of the rubber component. Further, the content is preferably 10 parts by mass or less, more preferably 7 parts by mass or less. Within the above numerical range, the effects of the present invention tend to be obtained satisfactorily.

The rubber composition of the present invention preferably contains 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.

The content of stearic acid is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more with respect to 100 parts by mass of the rubber component. Further, the content is preferably 10 parts by mass or less, more preferably 5 parts by mass or less. Within the above numerical range, the effects of the present invention tend to be obtained satisfactorily.

The rubber composition of the present invention preferably contains 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 Co., Ltd. Can be used.

The content of zinc oxide is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more with respect to 100 parts by mass of the rubber component. Further, the content is preferably 10 parts by mass or less, more preferably 5 parts by mass or less. If it is within the above numerical range, the effect of the present invention tends to be obtained better.

The rubber composition of the present invention preferably contains sulfur.
Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, and soluble sulfur that are 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.

The sulfur content is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more with respect to 100 parts by mass of the rubber component. The content is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and still more preferably 3 parts by mass or less. Within the above numerical range, the effects of the present invention tend to be obtained satisfactorily.

The rubber composition of the present invention preferably contains 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-benzothiazolesulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, N, N′-diisopropyl-2-benzothiazolesulfenamide, etc. The sulfenami And guanidine vulcanization accelerators such as diphenyl guanidine, diortolyl guanidine, and orthotolyl biguanidine. 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.

The content of the vulcanization accelerator is preferably 1 part by mass or more, more preferably 3 parts by mass or more with respect to 100 parts by mass of the rubber component. Further, the content is preferably 10 parts by mass or less, more preferably 7 parts by mass or less. Within the above numerical range, the effects of the present invention tend to be obtained satisfactorily.

In the rubber composition of the present invention, inorganic fillers and organic fillers other than silica, aluminum hydroxide, aluminum oxide and carbon black; softeners other than oil; vulcanizing agents other than sulfur (for example, organic crosslinking agents); Etc. may be included.

Examples of the inorganic filler include talc, magnesium hydroxide, magnesium oxide, magnesium sulfate, titanium white, titanium black, calcium oxide, calcium hydroxide, magnesium aluminum oxide, clay, pyrophyllite, bentonite, aluminum silicate, and silicic acid. Examples include magnesium, calcium silicate, aluminum calcium silicate, magnesium silicate, silicon carbide, zirconium, zirconium oxide and the like. Examples of the organic filler include cellulose nanofibers. These may be used alone or in combination of two or more.
The said inorganic filler and organic filler are mix | blended at 50 mass parts or less with respect to 100 mass parts of rubber components, for example.

Examples of the softening agent include liquid diene polymers.
The liquid diene polymer is a diene polymer in a liquid state at normal temperature (25 ° C.). The liquid diene polymer preferably has a polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of 1.0 × 10 ^{3 to} 2.0 × 10 ^5. It is more preferable that it is * 10 < ³ > -1.5 * 10 < ⁴ >.
Examples of the liquid diene polymer include a liquid styrene butadiene copolymer (liquid SBR), a liquid butadiene polymer (liquid BR), a liquid isoprene polymer (liquid IR), and a liquid styrene isoprene copolymer (liquid SIR). It is done. These may be used alone or in combination of two or more.
For example, the liquid diene polymer is blended at 50 parts by mass or less with respect to 100 parts by mass of the rubber component.

The organic crosslinking agent is not particularly limited, and examples thereof include maleimide compounds, alkylphenol / sulfur chloride condensates, organic peroxides, and amine organic sulfides. These may be used alone or in combination of two or more, and may be used in combination with sulfur.
An organic crosslinking agent is mix | blended at 10 mass parts or less with respect to 100 mass parts of rubber components, for example.

The rubber composition of the present invention is produced by a general method. That is, it can be produced by a method of kneading the above components with a Banbury mixer, a kneader, an open roll or the like and then vulcanizing.

As kneading conditions, when additives other than the vulcanizing agent and the vulcanization accelerator are blended, the kneading temperature is usually 50 to 200 ° C., preferably 80 to 190 ° C., and the kneading time is usually 30 seconds. -30 minutes, preferably 1-30 minutes.
When blending a vulcanizing agent and a vulcanization accelerator, the kneading temperature is usually 100 ° C. or lower, preferably room temperature to 80 ° C. Further, a composition containing a vulcanizing agent and a vulcanization accelerator is usually subjected to a vulcanization treatment such as press vulcanization. The vulcanization temperature is usually 120 to 200 ° C, preferably 140 to 180 ° C.

The rubber composition of the present invention is suitably used for treads (cap treads), but members other than treads, for example, sidewalls, base treads, under treads, clinch apex, bead apex, breaker cushion rubber, carcass cord You may use for the rubber | gum for coating | cover, an insulation, a chafer, an inner liner, etc., and the side reinforcement layer of a run flat tire.

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

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 (adjusted in the following Production Example 1, styrene content: 35% by mass, vinyl content: 50% by mass)
SBR2: Modified SBR (adjusted in Production Example 2 below, styrene content: 10% by mass, vinyl content: 40% by mass)
BR: BR150B manufactured by Ube Industries, Ltd. (cis content: 97% by mass)
Carbon Black: Show Black N220 (N ₂ SA: 111 m ² / g, DBP absorption: 115 ml / 100 g) manufactured by Cabot Japan
Silica 1: VN3 manufactured by Evonik (N ₂ SA: 175 m ² / g)
Silica 2: 115GR manufactured by Solvay Japan Co., Ltd. (N ₂ SA: 115 m ² / g)
Aluminum hydroxide: Aluminum hydroxide (D50: 0.4 μm, N ₂ SA: 15 m ² / g, oil absorption: 48 ml / 100 g)
Silane coupling agent: 3-octanoylthio-1-propyltriethoxysilane oil: naphthenic process oil resin: Sylvatrax 4401 (copolymer of α-methylstyrene and styrene, softening point: 85 ° C., Tg: Arizona Chemical Co., Ltd. 43 ° C)
Wax: Paraffin wax Stearic acid: Stearic acid “Kashiwa” manufactured by NOF Corporation
Zinc oxide: Zinc Hua No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Sulfur: Powder sulfur anti-aging agent manufactured by Tsurumi Chemical Co., Ltd. 1: N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylene Diamine aging inhibitor 2: poly (2,2,4-trimethyl-1,2-dihydroquinoline)
Vulcanization accelerator 1: N-tert-butyl-2-benzothiazolylsulfenamide Vulcanization accelerator 2: Diphenylguanidine

(Production Example 1)
In a nitrogen atmosphere, 3- (N, N-dimethylamino) propyltrimethoxysilane (3-dimethylaminopropyltrimethoxysilane) (manufactured by Amax Co.) was placed in a 100 ml volumetric flask, and anhydrous hexane (Kanto Chemical Co., Ltd.) was added. )) Was added to prepare a terminal modifier.
N-Hexane, styrene (manufactured by Kanto Chemical Co., Inc.), butadiene, and tetramethylethylenediamine were added to a pressure-resistant container sufficiently purged with nitrogen, and the temperature was raised to 40 ° C. Next, after adding butyl lithium (manufactured by Kanto Chemical Co., Inc.), the temperature was raised to 50 ° C. and stirred. Next, a silicon tetrachloride / hexane solution was added and stirred. Next, the terminal modifier was added and stirred. After adding methanol (manufactured by Kanto Chemical Co., Ltd.) in which 2,6-tert-butyl-p-cresol (manufactured by Ouchi Shinsei Chemical Co., Ltd.) is dissolved in the reaction solution, the reaction solution is a stainless steel container containing methanol The aggregates were collected in The obtained aggregate was dried under reduced pressure for 24 hours to obtain modified SBR (SBR1). The obtained SBR1 had a styrene content of 35% by mass, a vinyl content of 50% by mass, and a weight average molecular weight Mw of 700,000.

(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%, butadiene was added, and after further polymerizing for 5 minutes, methyltriethoxysilane 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. Next, the solvent was removed by steam stripping, and drying was performed with a hot roll adjusted to 110 ° C. to obtain a modified styrene butadiene rubber (SBR2). The obtained SBR2 had a styrene content of 10% by mass, a vinyl content of 40% by mass, and a weight average molecular weight Mw of 200,000.

<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 170 ° C. for 10 minutes, and a test tire ( Size: 195 / 65R15). The evaluation shown in Table 1 was performed using the obtained test tire, and the results are shown in Table 1.

(Low fuel consumption)
Using a rolling resistance tester, the rolling resistance when a test tire is run at a rim (15 × 6JJ), internal pressure (230 kPa), load (3.43 kN), speed (80 km / h) is measured and compared. Example 1 is shown as an index when the index is 100 (low fuel consumption index). A larger index indicates better fuel efficiency.

(Wet grip performance)
Each test tire was mounted on all wheels of a vehicle (domestic FF2000cc), the braking distance from the initial speed of 100 km / h was obtained on the wet asphalt road surface, and displayed as an index when Comparative Example 1 was set to 100 (wet Grip performance index). The larger the index, the shorter the braking distance and the better the wet grip performance.

(Abrasion resistance)
Each test tire was mounted on a domestic FF vehicle, the groove depth of the tire tread portion after a mileage of 8000 km was measured, and the mileage when the tire groove depth decreased by 1 mm was calculated. Expressed as an index of time (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.

From Table 1, it is clear that Examples 1 to 10, which are rubber compositions each containing a predetermined amount of SBR A, SBR B, and silica, can improve fuel economy, wet grip performance and wear resistance in a well-balanced manner. became.

In particular, according to Example 1 and Comparative Examples 1 to 3, by combining a predetermined amount of SBR A and SBR B with a predetermined amount of silica (1) and (2), low fuel consumption, wet grip performance and wear resistance are achieved. It became clear that the performance balance of sex was remarkably improved.

Claims (5)

A rubber component having a styrene-butadiene rubber content of 80% by mass or more, and 40 to 80 parts by mass of silica with respect to 100 parts by mass of the rubber component;
In 100% by mass of the styrene butadiene rubber, the content of styrene butadiene rubber A having a styrene content of 30 to 40% by mass and a vinyl content of 45 to 55% by mass is 50 to 75% by mass, the styrene content is 3 to 15% by mass, and the vinyl content is 35. A rubber composition for tires, wherein the content of styrene butadiene rubber B of ˜45 mass% is 20-40 mass%. The tire rubber composition according to claim 1, wherein the total content of aluminum hydroxide and aluminum oxide is 5 to 15 parts by mass with respect to 100 parts by mass of the rubber component. The silica in 100% by mass, the content of nitrogen adsorption specific surface area 150 to 200 m ² / g of silica (1) is 50 to 75 mass%, the nitrogen adsorption specific surface area 90~120m ² / g of silica (2) The rubber composition for tires according to claim 1 or 2, wherein is 20 to 40% by mass. The tire rubber composition according to claim 3, wherein the content of the styrene butadiene rubber A and silica (1) with respect to 100 parts by mass of the rubber component satisfies the following formula.
0.8 ≦ styrene butadiene rubber A content / silica (1) content ≦ 2.0 The pneumatic tire produced using the rubber composition in any one of Claims 1-4.