JP2012255074A - Rubber composition and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition which is capable of improving fuel consumption saving, wet grip performance, wear resistance and steering stability in a balanced manner, and a pneumatic tire which uses the same.SOLUTION: The rubber composition contains a rubber component, a silica (1) that has a nitrogen adsorption specific surface area of ≤100 m/g, and a silica (2) that has a nitrogen adsorption specific surface area of ≥180 m/g. In the rubber composition, the content of a conjugated diene polymer, which has a constituent unit derived from a conjugated diene and a constituent unit represented by formula (I) and at least one end of which is modified with a silicon compound that has -CO- and -C-O-C-, is ≥5 mass% per 100 mass% of the rubber component, and the total content of the silica (1) and the silica (2) per 100 pts.mass of the rubber component is 30-150 pts.mass. In the formula, X, Xand Xeach independently represent a group represented by formula (Ia) (wherein Rand Reach independently represent 1-6C hydrocarbyl, 1-6C substituted hydrocarbyl, silyl or substituted silyl, and Rand Rmay bond to each other to form a ring structure together with N), hydroxyl, hydrocarbyl or substituted hydrocarbyl, and at least one of X, Xand Xis a group represented by formula (Ia) or hydroxyl.

Description

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

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 efficiency, a method of reducing the amount of filler and suppressing the heat generation of the rubber composition is known. However, when the amount of the filler is reduced, the hardness of the rubber composition may be lowered and steering stability may be deteriorated, and the wear resistance and wet grip performance may be deteriorated. Therefore, there is a need for a method for improving fuel economy, wet grip performance, wear resistance, and steering stability in a well-balanced manner.

Patent Document 1 discloses that low fuel consumption can be improved by blending a diene rubber modified with an organosilicon compound containing an amino group and an alkoxy group. Patent Document 2 discloses anhydrous silica and hydrous silica. It is disclosed that wet grip performance can be improved by using together. However, there is still room for improvement in terms of improving fuel economy, wet grip performance, wear resistance, and steering stability in a well-balanced manner.

JP 2000-344955 A JP 2003-192842 A

An object of the present invention is to solve the above-mentioned problems and to provide a rubber composition that can improve the fuel efficiency, wet grip performance, wear resistance, and steering stability in a well-balanced manner, and a pneumatic tire using the rubber composition. .

［式中、Ｘ^１、Ｘ^２及びＸ^３は、それぞれ独立に、下式（Ｉａ）で表される基、水酸基、ヒドロカルビル基又は置換ヒドロカルビル基を表し、Ｘ^１、Ｘ^２及びＸ^３の少なくとも１つが、下式（Ｉａ）で表される基又は水酸基である。］

［式中、Ｒ^１及びＲ^２は、それぞれ独立に、炭素原子数が１〜６のヒドロカルビル基、炭素原子数が１〜６の置換ヒドロカルビル基、シリル基又は置換シリル基を表し、Ｒ^１及びＲ^２は結合して窒素原子と共に環構造を形成していてもよい。］

The present invention contains a rubber component, silica (1) having a nitrogen adsorption specific surface area of 100 m ² / g or less, and silica (2) having a nitrogen adsorption specific surface area of 180 m ² / g or more, and the rubber component Among 100% by mass, it has a structural unit based on a conjugated diene and a structural unit represented by the following formula (I), and is represented by a group represented by the following formula (II) and / or the following formula (III): The content of the conjugated diene polymer in which at least one end of the polymer is modified with a silicon compound having a group is 5% by mass or more, and the silica (1) and (2) of 100 parts by mass of the rubber component It is related with the rubber composition whose total content is 30-150 mass parts.

[Wherein, X ¹ , X ² and X ³ each independently represent a group represented by the following formula (Ia), a hydroxyl group, a hydrocarbyl group or a substituted hydrocarbyl group, and at least ^one of X ¹ , X ² and X ³ One is a group or a hydroxyl group represented by the following formula (Ia). ]

[Wherein, R ¹ and R ² independently denote a hydrocarbyl group having 1 to 6 carbon atoms, a substituted hydrocarbyl group having 1-6 carbon atoms, or a substituted silyl group, R ¹ and R ² may be bonded to form a ring structure with the nitrogen atom. ]

R ¹ and R ^{2 in} formula (Ia) are preferably hydrocarbyl groups having 1 to 6 carbon atoms.

^Two of X ¹ , X ² and X ^{3 in} the formula (I) are preferably a group or a hydroxyl group represented by the formula (Ia).

［式中、Ｒ^３、Ｒ^４及びＲ^５は、それぞれ独立に、炭素原子数が１〜４のヒドロカルビル基又は炭素原子数が１〜４のヒドロカルビルオキシ基を表し、Ｒ^３、Ｒ^４及びＲ^５の少なくとも１つがヒドロカルビルオキシ基である。］ It is preferable that the silicon compound has a group represented by the following formula (IV).

[Wherein R ³ , R ⁴ and R ⁵ each independently represent a hydrocarbyl group having 1 to 4 carbon atoms or a hydrocarbyloxy group having 1 to 4 carbon atoms, and R ³ , R ⁴ and R 5 ^At least one of ⁵ is a hydrocarbyloxy group. ]

［式中、ｍは１〜１０の整数を表し、Ｒ^６、Ｒ^７及びＲ^８は、それぞれ独立に、炭素原子数が１〜４のヒドロカルビル基又は炭素原子数が１〜４のヒドロカルビルオキシ基を表し、Ｒ^６、Ｒ^７及びＲ^８の少なくとも１つがヒドロカルビルオキシ基である。］ It is preferable that the silicon compound has a group represented by the following formula (IIa).

[Wherein, m represents an integer of 1 to 10, and R ⁶ , R ⁷ and R ⁸ are each independently a hydrocarbyl group having 1 to 4 carbon atoms or a hydrocarbyloxy group having 1 to 4 carbon atoms. And at least one of R ⁶ , R ⁷ and R ⁸ is a hydrocarbyloxy group. ]

The vinyl bond content of the conjugated diene polymer is preferably 10 mol% or more and 80 mol% or less, with the content of structural units based on the conjugated diene being 100 mol%.

The rubber composition preferably contains natural rubber and / or butadiene rubber.

It is preferable that the content of silica (1) and the content of silica (2) satisfy the following formula.
[Content of silica (1)] × 0.2 ≦ [Content of silica (2)] ≦ [Content of silica (1)] × 6.5

The rubber composition is preferably used as a tread rubber composition.

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 in which a specific conjugated diene polymer and two types of silica having a specific nitrogen adsorption specific surface area are within a specific range, low fuel consumption, wet grip performance, It is possible to provide a pneumatic tire with improved wear and handling stability in a well-balanced manner.

［式中、Ｘ^１、Ｘ^２及びＸ^３は、それぞれ独立に、下式（Ｉａ）で表される基、水酸基、ヒドロカルビル基又は置換ヒドロカルビル基を表し、Ｘ^１、Ｘ^２及びＸ^３の少なくとも１つが、下式（Ｉａ）で表される基又は水酸基である。］

［式中、Ｒ^１及びＲ^２は、それぞれ独立に、炭素原子数が１〜６のヒドロカルビル基、炭素原子数が１〜６の置換ヒドロカルビル基、シリル基又は置換シリル基を表し、Ｒ^１及びＲ^２は結合して窒素原子と共に環構造を形成していてもよい。］

The rubber composition of the present invention has a structural unit based on a conjugated diene and a structural unit represented by the following formula (I), represented by a group represented by the following formula (II) and / or represented by the following formula (III): A conjugated diene polymer in which at least one end of the polymer is modified by a silicon compound having a group to be formed, silica (1) having a nitrogen adsorption specific surface area of 100 m ² / g or less, and a nitrogen adsorption specific surface area of 180 m ² / G or more of silica (2).

[Wherein, X ¹ , X ² and X ³ each independently represent a group represented by the following formula (Ia), a hydroxyl group, a hydrocarbyl group or a substituted hydrocarbyl group, and at least ^one of X ¹ , X ² and X ³ One is a group or a hydroxyl group represented by the following formula (Ia). ]

[Wherein, R ¹ and R ² independently denote a hydrocarbyl group having 1 to 6 carbon atoms, a substituted hydrocarbyl group having 1-6 carbon atoms, or a substituted silyl group, R ¹ and R ² may be bonded to form a ring structure with the nitrogen atom. ]

Examples of the conjugated diene based on the conjugated diene include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 1,3-hexadiene, and the like. These may be one type or two or more types. From the viewpoint of availability, 1,3-butadiene and isoprene are preferable.

X ¹ , X ² and X ³ in formula (I) of the structural unit represented by formula (I) each independently represent a group represented by formula (Ia), a hydroxyl group, a hydrocarbyl group or a substituted hydrocarbyl group. , X ¹ , X ² and X ³ are a group represented by the formula (Ia) or a hydroxyl group.

R ¹ and R ^{2 in} formula (Ia) each independently represent a hydrocarbyl group having 1 to 6 carbon atoms, a substituted hydrocarbyl group having 1 to 6 carbon atoms, a silyl group, or a substituted silyl group, and R ¹ And R ² may be bonded together to form a ring structure together with the nitrogen atom.

As used herein, a hydrocarbyl group represents a hydrocarbon residue. Here, the hydrocarbon residue represents a monovalent group obtained by removing hydrogen from a hydrocarbon. A substituted hydrocarbyl group represents a group in which one or more hydrogen atoms of a hydrocarbon residue are substituted with a substituent. The hydrocarbyloxy group represents a group in which a hydrogen atom of a hydroxyl group is substituted with a hydrocarbyl group, and the substituted hydrocarbyloxy group represents a group in which one or more hydrogen atoms of the hydrocarbyloxy group are substituted with a substituent. The substituted silyl group represents a group in which one or more hydrogen atoms of the silyl group are substituted with a substituent.

Examples of the hydrocarbyl group having 1 to 6 carbon atoms of R ¹ and R ² include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n- Examples thereof include alkyl groups such as pentyl group, neopentyl group, isopentyl group and n-hexyl group; cycloalkyl groups such as cyclohexyl group; phenyl groups and the like.

The substituted hydrocarbyl group having 1 to 6 carbon atoms in R ¹ and R ² includes at least one group selected from the group consisting of a group having a nitrogen atom, a group having an oxygen atom, and a group having a silicon atom. The substituted hydrocarbyl group which has as a substituent can be mention | raise | lifted. Examples of the group having a group having a nitrogen atom as a substituent include dialkylaminoalkyl groups such as a dimethylaminoethyl group and a diethylaminoethyl group. Examples of the group having a group having an oxygen atom as a substituent include methoxymethyl Group, alkoxyalkyl group such as methoxyethyl group, ethoxymethyl group, ethoxyethyl group and the like, and groups having a silicon atom as a substituent include trialkylsilylalkyl groups such as trimethylsilylmethyl group, etc. I can give you.

Examples of the substituted silyl group for R ¹ and R ² include trialkylsilyl groups such as a trimethylsilyl group, a triethylsilyl group, and a t-butyldimethylsilyl group.

The group to which R ¹ and R ² are bonded is a divalent group having 1 to 12 carbon atoms that may have at least one atom selected from the group consisting of a nitrogen atom, an oxygen atom and a silicon atom. Group. For example, trimethylene group, tetramethylene group, pentamethylene group, alkylene groups such as a hexamethylene group; oxy oxydialkylene groups such as dipropylene _{group; -CH 2 CH 2 -NH-CH} 2 - is represented by And a nitrogen-containing group such as a group represented by —CH ₂ CH ₂ —N═CH—.

The group to which R ¹ and R ² are bonded is preferably a nitrogen-containing group, a group represented by —CH ₂ CH ₂ —NH—CH ₂ —, a group represented by —CH ₂ CH ₂ —N═CH—. Is more preferable.

The hydrocarbyl group of R ¹ and R ² is preferably an alkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, further preferably a methyl group, an ethyl group, an n-propyl group, or an n-butyl group, Group, n-butyl group is particularly preferred. The substituted hydrocarbyl group for R ¹ and R ² is preferably an alkoxyalkyl group, and more preferably an alkoxyalkyl group having 1 to 4 carbon atoms. The substituted silyl group for R ¹ and R ² is preferably a trialkylsilyl group, and more preferably a trimethylsilyl group.

R ¹ and R ² are preferably an alkyl group, an alkoxyalkyl group, a substituted silyl group, or a nitrogen-containing group to which R ¹ and R ² are bonded, more preferably an alkyl group, still more preferably carbon. It is an alkyl group having 1 to 4 atoms, and more preferably a methyl group, an ethyl group, an n-propyl group, or an n-butyl group.

Examples of the group represented by the formula (Ia) include an acyclic amino group and a cyclic amino group.
Examples of the acyclic amino group include dimethylamino group, diethylamino group, di (n-propyl) amino group, di (isopropyl) amino group, di (n-butyl) amino group, di (sec-butyl) amino group, di ( dialkylamino groups such as tert-butyl) amino group, di (neopentyl) amino group, ethylmethylamino group; di (methoxymethyl) amino group, di (methoxyethyl) amino group, di (ethoxymethyl) amino group, di ( And di (alkoxyalkyl) amino groups such as ethoxyethyl) amino group; and di (trialkylsilyl) amino groups such as di (trimethylsilyl) amino group and di (t-butyldimethylsilyl) amino group.

Examples of the cyclic amino group include 1-pyrrolidinyl group, 1-piperidino group, 1-hexamethyleneimino group, 1-heptamethyleneimino group, 1-octamethyleneimino group, 1-decamethyleneimino group, 1-dodecamethyleneimino. 1-polymethyleneimino groups such as groups can be mentioned. Examples of the cyclic amino group include 1-imidazolyl group, 4,5-dihydro-1-imidazolyl group, 1-imidazolidinyl group, 1-piperazinyl group, morpholino group and the like.

The group represented by the formula (Ia) is preferably an acyclic amino group, more preferably a dialkylamino group, and still more preferably 1 to 1 carbon atoms from the viewpoint of economy and availability. A dialkylamino group substituted with 4 alkyl groups, and more preferably a dimethylamino group, a diethylamino group, a di (n-propyl) amino group, and a di (n-butyl) amino group.

Examples of the hydrocarbyl group of X ^{1 to} X ^{3 in} the formula (I) include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, and tert-butyl group. be able to. Examples of the substituted hydrocarbyl group include alkoxyalkyl groups such as a methoxymethyl group, an ethoxymethyl group, a methoxyethyl group, and an ethoxyethyl group.

The hydrocarbyl group of X ^{1 to} X ³ is preferably an alkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, and still more preferably a methyl group or an ethyl group. Furthermore, the substituted hydrocarbyl group X ¹ to X ^3, preferably an alkoxyalkyl group, more preferably an alkoxyalkyl group having 1 to 4 carbon atoms.

The hydrocarbyl group and substituted hydrocarbyl group of X ^{1 to} X ³ are preferably an alkyl group or an alkoxyalkyl group, and more preferably an alkyl group having 1 to 4 carbon atoms or an alkyl group having 1 to 4 carbon atoms. It is an alkoxyalkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, and still more preferably a methyl group or an ethyl group.

At least one of X ¹ , X ² and X ^{3 in} the formula (I) is a group or a hydroxyl group represented by the formula (Ia). Preferably, two or more of X ¹ , X ² and X ³ are a group or a hydroxyl group represented by the formula (Ia), more preferably ^{two of} X ¹ , X ² and X ³ are represented by the formula (Ia ) Or a hydroxyl group. Further, fuel economy, wet grip performance, wear resistance and steering stability in terms of good balance is obtained at a high level, preferably at least one of hydroxyl group of X ^1, X ² and X ^3, X ¹ , X ² and X ³ are more preferably a hydroxyl group, and ^{two of} X ¹ , X ² and X ³ are more preferably a hydroxyl group.

From the viewpoint of improving fuel economy, wet grip performance, wear resistance, and steering stability in a well-balanced manner, ^two structural units represented by formula (I) are X ¹ , X ^2, and X ³ are acyclic amino groups. Or the structural unit which is a hydroxyl group is preferable. As the structural unit in which ^{two of} X ¹ , X ² and X ³ are acyclic amino groups, bis (dialkylamino) alkylvinylsilane units are preferred, bis (dimethylamino) methylvinylsilane units, bis (diethylamino) methylvinylsilane units, Bis (di (n-propyl) amino) methylvinylsilane units and bis (di (n-butyl) amino) methylvinylsilane units are more preferred. As the structural unit in which two of X ¹ , X ² and X ³ are hydroxyl groups, a dihydroxyalkylvinylsilane unit is preferable, and a dihydroxymethylvinylsilane unit is more preferable.

The content of the structural unit represented by the formula (I) in the conjugated diene polymer is from the viewpoint of improving the fuel economy, wet grip performance, wear resistance and handling stability in a well-balanced manner. Preferably, it is 0.001 mmol / g polymer or more and 0.1 mmol / g polymer or less. More preferably, it is 0.002 mmol / g polymer or more and 0.07 mmol / g polymer or less. More preferably, it is 0.003 mmol / g polymer or more and 0.05 mmol / g polymer or less.

The conjugated diene polymer is a polymer obtained by modifying at least one end of a polymer with a silicon compound having a group represented by the following formula (II) and / or a group represented by the following formula (III). .

Examples of the group having a group represented by the formula (II) include an amide group, a carboxylic ester group, a methacryloyl group, and an acryloyl group. Examples of the group having a group represented by the formula (III) include oxydialkylene groups such as oxydimethylene group and oxydiethylene group; alkylene oxide groups such as epoxy group and tetrahydrofuranyl group.
In the present specification, the alkylene oxide group represents a monovalent group obtained by removing a hydrogen atom from a ring of a cyclic ether compound.

［式中、Ｒ^３、Ｒ^４及びＲ^５は、それぞれ独立に、炭素原子数が１〜４のヒドロカルビル基又は炭素原子数が１〜４のヒドロカルビルオキシ基を表し、Ｒ^３、Ｒ^４及びＲ^５の少なくとも１つがヒドロカルビルオキシ基である。］ The silicon compound preferably has a group represented by the following formula (IV).

[Wherein R ³ , R ⁴ and R ⁵ each independently represent a hydrocarbyl group having 1 to 4 carbon atoms or a hydrocarbyloxy group having 1 to 4 carbon atoms, and R ³ , R ⁴ and R 5 ^At least one of ⁵ is a hydrocarbyloxy group. ]

In formula (IV), examples of the hydrocarbyl group of R ³ , R ⁴ and R ⁵ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, and a tert-butyl group. An alkyl group etc. can be mention | raise | lifted. ^As the hydrocarbyl group of R 3, ^{R 4} and ^{R 5,} a methoxy group, an ethoxy group, n- propoxy group, isopropoxy group, n- butoxy group, sec- butoxy group, an alkoxy group such as t- butoxy Can give.

The hydrocarbyl group of R ³ , R ⁴ and R ⁵ is preferably an alkyl group, more preferably an alkyl group having 1 to 3 carbon atoms, still more preferably a methyl group or an ethyl group. . Further, the hydrocarbyloxy group of R ³ , R ⁴ and R ⁵ is preferably an alkoxy group, more preferably an alkoxy group having 1 to 3 carbon atoms, and still more preferably a methoxy group or ethoxy group. It is a group.

As R ³ , R ⁴ and R ⁵ , from the viewpoint of enhancing fuel economy, preferably at least two of R ³ , R ⁴ and R ⁵ are hydrocarbyloxy groups, and more preferably R ³ , R ⁴ and Three of R ⁵ are hydrocarbyloxy groups.

［式中、ｍは１〜１０の整数を表し、Ｒ^６、Ｒ^７及びＲ^８は、それぞれ独立に、炭素原子数が１〜４のヒドロカルビル基又は炭素原子数が１〜４のヒドロカルビルオキシ基を表し、Ｒ^６、Ｒ^７及びＲ^８の少なくとも１つがヒドロカルビルオキシ基である。］ Examples of the silicon compound having a group represented by the formula (II) and a group represented by the formula (IV) include a silicon compound having a group represented by the following formula (IIa).

[Wherein, m represents an integer of 1 to 10, and R ⁶ , R ⁷ and R ⁸ are each independently a hydrocarbyl group having 1 to 4 carbon atoms or a hydrocarbyloxy group having 1 to 4 carbon atoms. And at least one of R ⁶ , R ⁷ and R ⁸ is a hydrocarbyloxy group. ]

m represents an integer of 1 to 10. From the viewpoint of improving fuel economy, it is preferably 2 or more, and from the viewpoint of improving economy during production, it is preferably 4 or less. Particularly preferred is 3.

For R ⁶ , R ⁷ and R ⁸ , the exemplified groups and preferred groups are the same as the exemplified groups and preferred groups described above for R ³ , R ⁴ and R ⁵ in formula (IV).

［式中、ｎは１〜１０の整数を表し、Ｒ^１１、Ｒ^１２及びＲ^１３は、それぞれ独立に、炭素原子数が１〜４のヒドロカルビル基又は炭素原子数が１〜４のヒドロカルビルオキシ基を表し、Ｒ^１１、Ｒ^１２及びＲ^１３の少なくとも１つがヒドロカルビルオキシ基であり、Ｒ^１４及びＲ^１５は、それぞれ独立に、炭素原子数が１〜１０のヒドロカルビル基、炭素原子数が１〜１０の置換ヒドロカルビル基、炭素原子数が１〜１０のヒドロカルビルオキシ基又は炭素原子数が１〜１０の置換ヒドロカルビルオキシ基を表し、Ｒ^１４及びＲ^１５は結合していてもよい。］ Examples of the silicon compound having a group represented by the formula (IIa) include compounds represented by the following formula (IIb) or the following formula (IIc).

[Wherein, n represents an integer of 1 to 10, and R ¹¹ , R ¹² and R ¹³ are each independently a hydrocarbyl group having 1 to 4 carbon atoms or a hydrocarbyloxy group having 1 to 4 carbon atoms. Wherein at least one of R ¹¹ , R ¹² and R ¹³ is a hydrocarbyloxy group, R ¹⁴ and R ¹⁵ are each independently a hydrocarbyl group having 1 to 10 carbon atoms and a carbon number of 1 to 10 A substituted hydrocarbyl group, a hydrocarbyloxy group having 1 to 10 carbon atoms, or a substituted hydrocarbyloxy group having 1 to 10 carbon atoms, and R ¹⁴ and R ¹⁵ may be bonded. ]

［式中、ｐ、ｑ及びｒは、それぞれ独立に、１〜１０の整数を表し、Ｒ^２１〜Ｒ^２９は、それぞれ独立に、炭素原子数が１〜４のヒドロカルビル基又は炭素原子数が１〜４のヒドロカルビルオキシ基を表し、Ｒ^２１、Ｒ^２２及びＲ^２３の少なくとも１つがヒドロカルビルオキシ基であり、Ｒ^２４、Ｒ^２５及びＲ^２６の少なくとも１つがヒドロカルビルオキシ基であり、Ｒ^２７、Ｒ^２８及びＲ^２９の少なくとも１つがヒドロカルビルオキシ基である。］

[Wherein, p, q and r each independently represent an integer of 1 to 10, and R ^{21 to} R ²⁹ each independently represents a hydrocarbyl group having 1 to 4 carbon atoms or 1 carbon atom. represents to 4 hydrocarbyloxy ^group, at least one of hydrocarbyloxy groups of R ^{21, R 22} and ^{R 23,} at least one of hydrocarbyloxy groups R ^{24, R 25} and ^{R 26,} R ^{27, R 28} And at least one of R ²⁹ is a hydrocarbyloxy group. ]

N in the formula (IIb) represents an integer of 1 to 10. From the viewpoint of improving the fuel efficiency, wet grip performance, wear resistance, and steering stability in a well-balanced manner, it is preferably 2 or more, and preferably 4 or less from the viewpoint of improving economy during production. Particularly preferred is 3.

In the formula (IIb), examples of the hydrocarbyl group of R ¹¹ , R ¹² and R ¹³ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, and a tert-butyl group. An alkyl group etc. can be mention | raise | lifted. Moreover, as hydrocarbyloxy group of R < ¹¹ >, R < ¹² > and R < ¹³ >, alkoxy groups such as methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, sec-butoxy group and t-butoxy group Can give.

The hydrocarbyl group of R ¹¹ , R ¹² and R ¹³ is preferably an alkyl group, more preferably an alkyl group having 1 to 3 carbon atoms, still more preferably a methyl group or an ethyl group. . Further, the hydrocarbyloxy group of R ¹¹ , R ¹² and R ¹³ is preferably an alkoxy group, more preferably an alkoxy group having 1 to 3 carbon atoms, and still more preferably a methoxy group or ethoxy group. It is a group.

The R ^{11, R 12} and ^{R 13,} fuel economy, wet grip performance, from the viewpoint of enhancing a balanced wear resistance and steering stability, ^preferably at least two hydrocarbyloxy of R ^{11, R 12} and ^{R 13} More preferably three of R ¹¹ , R ¹² and R ¹³ are hydrocarbyloxy groups.

Examples of the hydrocarbyl group of R ¹⁴ and R ¹⁵ include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, and tert-butyl group.

The substituted hydrocarbyl group of R ¹⁴ and R ^{15 is} a substituted hydrocarbyl group having at least one group selected from the group consisting of a group having a nitrogen atom, a group having an oxygen atom and a group having a silicon atom as a substituent. I can give you. Examples of the group having a group having a nitrogen atom as a substituent include dialkylaminoalkyl groups such as a dimethylaminoethyl group and a diethylaminoethyl group. Examples of the group having a group having an oxygen atom as a substituent include methoxymethyl Group, alkoxyalkyl group such as methoxyethyl group, ethoxymethyl group, ethoxyethyl group and the like. Examples of the group having a silicon atom group as a substituent include trialkylsilyl groups such as trimethylsilylmethyl group and triethylsilylmethyl group. Examples thereof include a silylalkyl group.

Examples of the hydrocarbyloxy group of R ¹⁴ and R ¹⁵ include alkoxy groups such as a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, and a t-butoxy group. . Examples of the substituted hydrocarbyloxy group for R ¹⁴ and R ¹⁵ include alkoxyalkoxy groups such as a methoxymethoxy group, a methoxyethoxy group, an ethoxymethoxy group, and an ethoxyethoxy group.

The group to which R ¹⁴ and R ¹⁵ are bonded is a divalent divalent having 2 to 12 carbon atoms that may have at least one atom selected from the group consisting of a nitrogen atom, an oxygen atom and a silicon atom. Group. For example, trimethylene group, tetramethylene group, pentamethylene group, alkylene groups such as a hexamethylene group; oxy oxydialkylene groups such as dipropylene _{group; -CH 2 CH 2 -NH-CH} 2 - is represented by And a nitrogen-containing group such as a group represented by —CH ₂ CH ₂ —N═CH—.

R ¹⁴ is preferably an alkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, and still more preferably a methyl group and an ethyl group.

R ¹⁵ is preferably an alkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, and still more preferably a methyl group and an ethyl group.

P, q, and r in formula (IIc) each independently represents an integer of 1 to 10. From the viewpoint of improving the fuel efficiency, wet grip performance, wear resistance, and steering stability in a well-balanced manner, it is preferably 2 or more, and preferably 4 or less from the viewpoint of improving economy during production. Particularly preferred is 3.

In formula (IIc), examples of the hydrocarbyl group of R ^{21 to} R ²⁹ include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, and a tert-butyl group. Can give. Examples of the hydrocarbyloxy group represented by R ^{21 to} R ²⁹ include alkoxy groups such as a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, and a t-butoxy group. Can do.

The hydrocarbyl group of R ^{21 to} R ²⁹ is preferably an alkyl group, more preferably an alkyl group having 1 to 3 carbon atoms, and still more preferably a methyl group or an ethyl group. Further, the hydrocarbyloxy group of R ^{21 to} R ²⁹ is preferably an alkoxy group, more preferably an alkoxy group having 1 to 3 carbon atoms, and still more preferably a methoxy group or an ethoxy group. .

R ²¹ , R ²² and R ²³ are preferably at least two of R ²¹ , R ²² and R ²³ are hydrocarbyloxy from the viewpoint of improving fuel economy, wet grip performance, wear resistance and steering stability in a balanced manner. More preferably three of R ²¹ , R ²² and R ²³ are hydrocarbyloxy groups. The R ^{24, R 25} and ^{R 26,} fuel economy, wet grip performance, from the viewpoint of enhancing a balanced wear resistance and steering stability, ^preferably at least two hydrocarbyloxy of R ^{24, R 25} and ^{R 26} More preferably, three of R ²⁴ , R ²⁵ and R ²⁶ are hydrocarbyloxy groups. R ²⁷ , R ²⁸ and R ²⁹ are preferably at least two of R ²⁷ , R ²⁸ and R ²⁹ from the viewpoint of improving fuel economy, wet grip performance, wear resistance and steering stability in a well-balanced manner. A hydrocarbyloxy group, more preferably three of R ²⁷ , R ²⁸ and R ²⁹ are hydrocarbyloxy groups.

As the compound represented by the formula (IIb),
N-methyl-N- (trimethoxysilylmethyl) -acetamide,
N-methyl-N- (triethoxysilylmethyl) -acetamide,
N-methyl-N- (2-trimethoxysilylethyl) -acetamide,
N-methyl-N- (2-triethoxysilylethyl) -acetamide,
N-methyl-N- (3-trimethoxysilylpropyl) -acetamide,
N-alkyl-N-trialkoxysilylalkyl-acetamides such as N-methyl-N- (3-triethoxysilylpropyl) -acetamide;
N-methyl-N- (trimethoxysilylmethyl) -propionamide,
N-methyl-N- (triethoxysilylmethyl) -propionamide,
N-methyl-N- (2-trimethoxysilylethyl) -propionamide,
N-methyl-N- (2-triethoxysilylethyl) -propionamide,
N-methyl-N- (3-trimethoxysilylpropyl) -propionamide,
N-alkyl-N-trialkoxysilylalkyl-propionamide, such as N-methyl-N- (3-triethoxysilylpropyl) -propionamide,
N-alkyl-N-trialkoxysilylalkyl-substituted carboxylic acid amides can be mentioned.

As the compound represented by the formula (IIb), preferably
N-alkyl-N-trialkoxysilylalkyl-substituted carboxylic acid amide,
More preferably,
N-alkyl-N-trialkoxysilylalkyl-propionamide,
More preferably,
N-methyl-N- (3-trimethoxysilylpropyl) -propionamide,
N-methyl-N- (3-triethoxysilylpropyl) -propionamide.

As the compound represented by the formula (IIc),
1,3,5-tris (3-trimethoxysilylmethyl) isocyanurate,
1,3,5-tris (3-triethoxysilylmethyl) isocyanurate,
1,3,5-tris (3-trimethoxysilylethyl) isocyanurate,
1,3,5-tris (3-triethoxysilylethyl) isocyanurate,
1,3,5-tris (3-trimethoxysilylpropyl) isocyanurate,
Mention may be made of 1,3,5-tris (trialkoxyalkyl) isocyanurate such as 1,3,5-tris (3-triethoxysilylpropyl) isocyanurate.

As the compound represented by the formula (IIc), preferably
1,3,5-tris (3-trimethoxysilylpropyl) isocyanurate,
1,3,5-tris (3-triethoxysilylpropyl) isocyanurate.

［式中、ｓは１〜１０の整数を表し、Ｒ^３１、Ｒ^３２及びＲ^３３は、それぞれ独立に、炭素原子数が１〜４のヒドロカルビル基又は炭素原子数が１〜４のヒドロカルビルオキシ基を表し、Ｒ^３１、Ｒ^３２及びＲ^３３の少なくとも１つがヒドロカルビルオキシ基であり、Ｒ^３４は、炭素原子数が１〜１０のヒドロカルビル基又は炭素原子数が１〜１０の置換ヒドロカルビル基を表す。］ Examples of the silicon compound having a group represented by the formula (III) and a group represented by the formula (IV) include a silicon compound represented by the following formula (IIIa).

[Wherein, s represents an integer of 1 to 10, and R ³¹ , R ³² and R ³³ are each independently a hydrocarbyl group having 1 to 4 carbon atoms or a hydrocarbyloxy group having 1 to 4 carbon atoms. Wherein at least one of R ³¹ , R ³² and R ³³ is a hydrocarbyloxy group, and R ³⁴ represents a hydrocarbyl group having 1 to 10 carbon atoms or a substituted hydrocarbyl group having 1 to 10 carbon atoms. ]

S in formula (IIIa) represents an integer of 1 to 10. From the viewpoint of improving the fuel efficiency, wet grip performance, wear resistance, and steering stability in a well-balanced manner, it is preferably 2 or more, and preferably 4 or less from the viewpoint of improving economy during production. Particularly preferred is 3.

In the formula (IIIa), examples of the hydrocarbyl group of R ³¹ , R ³² and R ³³ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group and a tert-butyl group. An alkyl group etc. can be mention | raise | lifted. The hydrocarbyloxy group of R ³¹ , R ³² and R ^{33 is} an alkoxy group such as a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group or a t-butoxy group. Can give.

The hydrocarbyl group of R ³¹ , R ³² and R ³³ is preferably an alkyl group, more preferably an alkyl group having 1 to 3 carbon atoms, still more preferably a methyl group or an ethyl group. . Further, the hydrocarbyloxy group of R ³¹ , R ³² and R ³³ is preferably an alkoxy group, more preferably an alkoxy group having 1 to 3 carbon atoms, and still more preferably a methoxy group or ethoxy group. It is a group.

R ³¹ , R ³² and R ³³ are preferably at least two of R ³¹ , R ³² and R ³³ are hydrocarbyloxy from the viewpoint of improving fuel economy, wet grip performance, wear resistance and steering stability in a balanced manner. More preferably three of R ³¹ , R ³² and R ³³ are hydrocarbyloxy groups.

Examples of the hydrocarbyl group of R ³⁴ include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, and tert-butyl group.

Examples of the substituted hydrocarbyl group of R ³⁴ include a substituted hydrocarbyl group having as a substituent at least one group selected from the group consisting of a group having a nitrogen atom, a group having an oxygen atom, and a group having a silicon atom. it can. Examples of the group having a group having a nitrogen atom as a substituent include dialkylaminoalkyl groups such as a dimethylaminoethyl group and a diethylaminoethyl group. Examples of the group having a group having an oxygen atom as a substituent include methoxymethyl Group, alkoxyalkyl group such as methoxyethyl group, ethoxymethyl group and ethoxyethyl group; alkylene oxide alkyl group such as glycidyl group and tetrahydrofurfuryl group, and the like having a group having a silicon atom as a substituent. Includes a trialkylsilylalkyl group such as a trimethylsilylmethyl group.
In the present specification, the alkylene oxide alkyl group represents a group in which one or more hydrogen atoms of the alkyl group are substituted with an alkylene oxide group.

R ³⁴ is preferably an alkylene oxide alkyl group, more preferably a glycidyl group or a tetrahydrofurfuryl group.

As the compound represented by the formula (IIIa),
As a compound in which R ³⁴ is an alkyl group,
3- (methoxy) propyltrimethoxysilane,
3- (ethoxy) propyltrimethoxysilane,
3- (n-propoxy) propyltrimethoxysilane,
3- (isopropoxy) propyltrimethoxysilane,
3- (n-butoxy) propyltrimethoxysilane,
3- (sec-butoxy) propyltrimethoxysilane,
Mention may be made of 3- (alkoxy) propyltrialkoxysilanes such as 3- (t-butoxy) propyltrimethoxysilane.

As a compound in which R ³⁴ is an alkylene oxide alkyl group,
2-glycidoxyethyltrimethoxysilane,
3-glycidoxypropyltrimethoxysilane,
2-glycidoxyethyl triethoxysilane,
Glycidoxyalkyltrialkoxysilanes such as 3-glycidoxypropyltriethoxysilane;
2-tetrahydrofurfuryloxyethyltrimethoxysilane,
3-tetrahydrofurfuryloxypropyltrimethoxysilane,
2-tetrahydrofurfuryloxyethyl triethoxysilane,
Mention may be made of tetrahydrofurfuryloxyalkyltrialkoxysilanes such as 3-tetrahydrofurfuryloxypropyltriethoxysilane.

As a compound in which R ³⁴ is an alkoxyalkyl group,
3- (methoxymethoxy) propyltrimethoxysilane,
3- (methoxyethoxy) propyltrimethoxysilane,
3- (ethoxymethoxy) propyltrimethoxysilane,
3- (ethoxyethoxy) propyltrimethoxysilane,
3- (methoxymethoxy) propyltriethoxysilane,
3- (methoxyethoxy) propyltriethoxysilane,
3- (ethoxymethoxy) propyltriethoxysilane,
Mention may be made of 3- (alkoxyalkoxy) propyltrialkoxysilanes such as 3- (ethoxyethoxy) propyltriethoxysilane.

The compound represented by the formula (IIIa) is preferably a compound in which R ³⁴ is an alkylene oxide alkyl group, more preferably
3-glycidoxypropyltrimethoxysilane,
3-glycidoxypropyltriethoxysilane,
3-tetrahydrofurfuryloxypropyltrimethoxysilane,
3-tetrahydrofurfuryloxypropyltriethoxysilane.

Examples of the silicon compound having a group represented by the formula (II), a group represented by the formula (III), and a group represented by the formula (IV) include 3-acryloxyalkyltrialkoxysilane and 3-methacryloxyalkyltrialkoxysilane. Can give.

Examples of the 3-acryloxyalkyltrialkoxysilane include 3-acryloxypropyltrialkoxysilane such as 3-acryloxypropyltrimethoxysilane and 3-acryloxypropyltriethoxysilane.
Examples of the 3-methacryloxyalkyltrialkoxysilane include 3-methacryloxypropyltrialkoxysilane such as 3-methacryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane.

Examples of the silicon compound having a group represented by the formula (II), a group represented by the formula (III), and a group represented by the formula (IV) include trialkoxysilylalkyl succinic anhydride and trialkoxysilylalkyl maleic anhydride. Can give.

Examples of trialkoxysilylalkyl succinic anhydrides include 3-trialkoxysilylpropyl succinic anhydrides such as 3-trimethoxysilylpropyl succinic anhydride and 3-triethoxysilylpropyl succinic anhydride.
Examples of the trialkoxysilylalkyl maleic anhydride include 3-trialkoxysilylpropyl maleic anhydride such as 3-trimethoxysilylpropyl maleic anhydride and 3-triethoxysilylpropyl maleic anhydride.

The conjugated diene polymer may have a constituent unit based on another monomer in addition to the constituent unit based on the conjugated diene (conjugated diene unit). Examples of the other monomer include aromatic vinyl, vinyl nitrile, and unsaturated carboxylic acid ester. Examples of the aromatic vinyl include styrene, α-methylstyrene, vinyl toluene, vinyl naphthalene, divinyl benzene, trivinyl benzene, and divinyl naphthalene. Examples of the vinyl nitrile include acrylonitrile, and examples of the unsaturated carboxylic acid ester include methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate. Among these, aromatic vinyl is preferable, and styrene is more preferable.

The conjugated diene polymer preferably has a structural unit based on aromatic vinyl (aromatic vinyl unit) from the viewpoint of wear resistance. The content of the aromatic vinyl unit is preferably a conjugated diene unit. And the total amount of aromatic vinyl units is 100% by mass, preferably 10% by mass or more (conjugated diene unit content is 90% by mass or less), more preferably 15% by mass or more (conjugate diene unit content) Is 85% by mass or less). Further, from the viewpoint of low fuel consumption, the content of the aromatic vinyl unit is preferably 50% by mass or less (the content of the conjugated diene unit is 50% by mass or more), more preferably 45% by mass or less (conjugated diene). The unit content is 55% by mass or more).

The vinyl bond content of the conjugated diene polymer is preferably 80 mol% or less, more preferably 70 mol% or less from the viewpoint of fuel efficiency, with the content of the conjugated diene unit being 100 mol%. Moreover, from a viewpoint of wet grip performance, Preferably it is 10 mol% or more, More preferably, it is 15 mol% or more, More preferably, it is 20 mol% or more, Most preferably, it is 40 mol% or more. The vinyl bond amount is determined from the absorption intensity in the vicinity of 910 cm ^−1, which is the absorption peak of the vinyl group, by infrared spectroscopy.

The molecular weight distribution of the conjugated diene polymer is preferably 1 to 5, more preferably 1 to 2, from the viewpoint of low fuel consumption. The molecular weight distribution is obtained by measuring the number average molecular weight (Mn) and the weight average molecular weight (Mw) by gel permeation chromatography (GPC) method and dividing Mw by Mn.

［式中、Ｘ^４、Ｘ^５及びＸ^６は、それぞれ独立に、下式（Ｖａ）で表される基、ヒドロカルビル基又は置換ヒドロカルビル基を表し、Ｘ^４、Ｘ^５及びＸ^６の少なくとも１つが、下式（Ｖａ）で表される基である。］

［式中、Ｒ^９及びＲ^１０は、それぞれ独立に、炭素原子数が１〜６のヒドロカルビル基、炭素原子数が１〜６の置換ヒドロカルビル基、シリル基又は置換シリル基を表し、Ｒ^９及びＲ^１０は結合して窒素原子と共に環構造を形成していてもよい。］
（工程Ｂ）：工程Ａで得られた重合体と下式（ＩＩ）で表される基及び／又は下式（ＩＩＩ）で表される基を有するケイ素化合物とを反応させる工程。

As a suitable production method of the conjugated diene polymer, there can be mentioned a production method having the following steps A and B.
(Step A): A monomer containing a conjugated diene and a vinyl compound represented by the following formula (V) is polymerized with an alkali metal catalyst in a hydrocarbon solvent, and a monomer unit based on the conjugated diene and A step of obtaining a polymer having an alkali metal derived from the catalyst at at least one end of a polymer chain having a monomer unit based on the vinyl compound represented by the formula (V).

[Wherein, X ⁴ , X ⁵ and X ⁶ each independently represent a group represented by the following formula (Va), a hydrocarbyl group or a substituted hydrocarbyl group, wherein at least one of X ⁴ , X ⁵ and X ⁶ is And a group represented by the following formula (Va). ]

Wherein, ^{R 9} and ^{R 10} are independently a hydrocarbyl group having 1 to 6 carbon atoms, a substituted hydrocarbyl group having 1-6 carbon atoms, or a substituted silyl group, ^{R 9} and R ¹⁰ may be bonded to form a ring structure with the nitrogen atom. ]
(Step B): A step of reacting the polymer obtained in Step A with a silicon compound having a group represented by the following formula (II) and / or a group represented by the following formula (III).

Examples of the alkali metal catalyst used in (Step A) include alkali metals, organic alkali metal compounds, complexes of alkali metals and polar compounds, oligomers having alkali metals, and the like. Examples of the alkali metal include lithium, sodium, potassium, rubidium, cesium and the like. Examples of the organic alkali metal compound include ethyl lithium, n-propyl lithium, iso-propyl lithium, n-butyl lithium, sec-butyl lithium, t-octyl lithium, n-decyl lithium, phenyl lithium, 2-naphthyl lithium, 2 -Butylphenyllithium, 4-phenylbutyllithium, cyclohexyllithium, 4-cyclopentyllithium, dimethylaminopropyllithium, diethylaminopropyllithium, t-butyldimethylsiloxypropyllithium, N-morpholinopropyllithium, lithium hexamethyleneimide, lithium pyrrole Zido, lithium piperidide, lithium heptamethylene imide, lithium dodecamethylene imide, 1,4-dilithio-2-butene, sodium naphthalenide, sodium Bifenirido, such as potassium napthalenide can be mentioned. Examples of the complex of alkali metal and polar compound include potassium-tetrahydrofuran complex and potassium-diethoxyethane complex. Examples of the oligomer having alkali metal include sodium salt of α-methylstyrene tetramer. Can do. Among these, an organic lithium compound or an organic sodium compound is preferable, and an organic lithium compound or an organic sodium compound having 2 to 20 carbon atoms is more preferable.

The hydrocarbon solvent used in (Step A) is a solvent that does not deactivate the organic alkali metal compound catalyst, and examples thereof include aliphatic hydrocarbons, aromatic hydrocarbons, and alicyclic hydrocarbons. Examples of the aliphatic hydrocarbon include propane, n-butane, iso-butane, n-pentane, iso-pentane, n-hexane, propene, 1-butene, iso-butene, trans-2-butene, cis-2- Examples include butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene and the like. In addition, examples of the aromatic hydrocarbon include benzene, toluene, xylene, and ethylbenzene. Examples of the alicyclic hydrocarbon include cyclopentane and cyclohexane. These may be used alone or in combination of two or more. In these, a C2-C12 hydrocarbon is preferable.

In (Step A), a monomer containing a conjugated diene and a vinyl compound represented by the formula (V) is polymerized, and a conjugated diene polymer having an alkali metal derived from the above-mentioned alkali metal catalyst at the polymer chain end. Manufacturing. Examples of the conjugated diene include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, and 1,3-hexadiene. Used in combination of more than one species. Among these, 1,3-butadiene and isoprene are preferable from the viewpoint of availability.

X ⁴ , X ⁵ and X ⁶ in the formula (V) each independently represent a group represented by the formula (Va), a hydrocarbyl group or a substituted hydrocarbyl group, and at least one of X ⁴ , X ⁵ and X ⁶ Is a group represented by the formula (Va).

R ⁹ and R ^{10 in} formula (Va) each independently represent a hydrocarbyl group having 1 to 6 carbon atoms, a substituted hydrocarbyl group having 1 to 6 carbon atoms, a silyl group, or a substituted silyl group, and R ⁹ And R ¹⁰ may combine with each other to form a ring structure together with the nitrogen atom.

Examples of the hydrocarbyl group having 1 to 6 carbon atoms of R ⁹ and R ¹⁰ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n- Examples thereof include alkyl groups such as pentyl group, neopentyl group, isopentyl group and n-hexyl group; cycloalkyl groups such as cyclohexyl group; phenyl groups and the like.

The substituted hydrocarbyl group having 1 to 6 carbon atoms in R ⁹ and R ¹⁰ is at least one group selected from the group consisting of a group having a nitrogen atom, a group having an oxygen atom, and a group having a silicon atom. The substituted hydrocarbyl group which has as a substituent can be mention | raise | lifted. Examples of the group having a group having a nitrogen atom as a substituent include dialkylaminoalkyl groups such as a dimethylaminoethyl group and a diethylaminoethyl group. Examples of the group having a group having an oxygen atom as a substituent include methoxymethyl Group, alkoxyalkyl group such as methoxyethyl group, ethoxymethyl group, ethoxyethyl group and the like, and groups having a silicon atom as a substituent include trialkylsilylalkyl groups such as trimethylsilylmethyl group, etc. I can give you.

Examples of the substituted silyl group of R ⁹ and R ¹⁰ include trialkylsilyl groups such as trimethylsilyl group, triethylsilyl group, and t-butyldimethylsilyl group.

The group to which R ⁹ and R ¹⁰ are bonded is a divalent group having 1 to 12 carbon atoms that may have at least one atom selected from the group consisting of a nitrogen atom, an oxygen atom and a silicon atom. Group. For example, trimethylene group, tetramethylene group, pentamethylene group, alkylene groups such as a hexamethylene group; oxy oxydialkylene groups such as dipropylene _{group; -CH 2 CH 2 -NH-CH} 2 - is represented by And a nitrogen-containing group such as a group represented by —CH ₂ CH ₂ —N═CH—.

The group to which R ⁹ and R ¹⁰ are bonded is preferably a nitrogen-containing group, a group represented by —CH ₂ CH ₂ —NH—CH ₂ —, a group represented by —CH ₂ CH ₂ —N═CH—. Is more preferable.

The hydrocarbyl group of R ⁹ and R ¹⁰ is preferably an alkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group, an ethyl group, an n-propyl group, or an n-butyl group, Group, n-butyl group is particularly preferred. The substituted hydrocarbyl group for R ⁹ and R ¹⁰ is preferably an alkoxyalkyl group, more preferably an alkoxyalkyl group having 1 to 4 carbon atoms. The substituted silyl group for R ⁹ and R ¹⁰ is preferably a trialkylsilyl group, more preferably a trimethylsilyl group.

R ⁹ and R ¹⁰ are preferably an alkyl group, an alkoxyalkyl group, a substituted silyl group, or a nitrogen-containing group to which R ⁹ and R ¹⁰ are bonded, more preferably an alkyl group, still more preferably carbon. It is an alkyl group having 1 to 4 atoms, and more preferably a methyl group, an ethyl group, an n-propyl group, or an n-butyl group.

Examples of the group represented by the formula (Va) include an acyclic amino group and a cyclic amino group.
Examples of the acyclic amino group include dimethylamino group, diethylamino group, di (n-propyl) amino group, di (isopropyl) amino group, di (n-butyl) amino group, di (sec-butyl) amino group, di ( dialkylamino groups such as tert-butyl) amino group, di (neopentyl) amino group, ethylmethylamino group; di (methoxymethyl) amino group, di (methoxyethyl) amino group, di (ethoxymethyl) amino group, di ( And di (alkoxyalkyl) amino groups such as ethoxyethyl) amino group; and di (trialkylsilyl) amino groups such as di (trimethylsilyl) amino group and di (t-butyldimethylsilyl) amino group.

Examples of the cyclic amino group include 1-pyrrolidinyl group, 1-piperidino group, 1-hexamethyleneimino group, 1-heptamethyleneimino group, 1-octamethyleneimino group, 1-decamethyleneimino group, 1-dodecamethyleneimino. 1-polymethyleneimino groups such as groups can be mentioned. Examples of the cyclic amino group include 1-imidazolyl group, 4,5-dihydro-1-imidazolyl group, 1-imidazolidinyl group, 1-piperazinyl group, morpholino group and the like.

The group represented by the formula (Va) is preferably an acyclic amino group, more preferably a dialkylamino group, and still more preferably 1 to 1 carbon atoms from the viewpoint of economy and availability. A dialkylamino group substituted with 4 alkyl groups, and more preferably a dimethylamino group, a diethylamino group, a di (n-propyl) amino group, and a di (n-butyl) amino group.

Examples of the hydrocarbyl group of X ^{4 to} X ^{6 in} the formula (V) include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, and tert-butyl group. be able to. Examples of the substituted hydrocarbyl group include alkoxyalkyl groups such as a methoxymethyl group, an ethoxymethyl group, a methoxyethyl group, and an ethoxyethyl group.

The hydrocarbyl group of X ^{4 to} X ⁶ is preferably an alkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, and still more preferably a methyl group or an ethyl group. Furthermore, the substituted hydrocarbyl group X ⁴ to X ^6, preferably an alkoxyalkyl group, more preferably an alkoxyalkyl group having 1 to 4 carbon atoms.

The hydrocarbyl group and substituted hydrocarbyl group of X ^{4 to} X ⁶ are preferably an alkyl group or an alkoxyalkyl group, and more preferably an alkyl group having 1 to 4 carbon atoms or an alkyl group having 1 to 4 carbon atoms. It is an alkoxyalkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, and still more preferably a methyl group or an ethyl group.

At least one of X ⁴ , X ⁵ and X ^{6 in} the formula (V) is a group represented by the formula (Va). Preferably, two or more of X ⁴ , X ⁵ and X ⁶ are groups represented by the formula (Va), more preferably two of X ⁴ , X ⁵ and X ⁶ are represented by the formula (Va). It is a group represented.

As the vinyl compound represented by the formula (V) used in (Step A), one of X ^{4 to} X ⁶ is an acyclic amino group represented by the formula (Va), and two are hydrocarbyl groups or substituted hydrocarbyls. Examples of the group-containing compound include (dialkylamino) dialkylvinylsilane, {di (trialkylsilyl) amino} dialkylvinylsilane, (dialkylamino) dialkoxyalkylvinylsilane, and the like.
(Dialkylamino) dialkylvinylsilane includes (dimethylamino) dimethylvinylsilane, (ethylmethylamino) dimethylvinylsilane, (diethylamino) dimethylvinylsilane, (ethyl-n-propylamino) dimethylvinylsilane, (ethylisopropylamino) dimethylvinylsilane, ( Di (n-propyl) amino) dimethylvinylsilane, (diisopropylamino) dimethylvinylsilane, (n-butyl-n-propylamino) dimethylvinylsilane, (di (n-butyl) amino) dimethylvinylsilane,
(Dimethylamino) diethylvinylsilane, (ethylmethylamino) diethylvinylsilane, (diethylamino) diethylvinylsilane, (ethyl-n-propylamino) diethylvinylsilane, (ethylisopropylamino) diethylvinylsilane, (di (n-propyl) amino) diethyl Vinylsilane, (diisopropylamino) diethylvinylsilane, (n-butyl-n-propylamino) diethylvinylsilane, (di (n-butyl) amino) diethylvinylsilane,
(Dimethylamino) dipropylvinylsilane, (ethylmethylamino) dipropylvinylsilane, (diethylamino) dipropylvinylsilane, (ethyl-n-propylamino) dipropylvinylsilane, (ethylisopropylamino) dipropylvinylsilane, (di (n- Propyl) amino) dipropylvinylsilane, (diisopropylamino) dipropylvinylsilane, (n-butyl-n-propylamino) dipropylvinylsilane, (di (n-butyl) amino) dipropylvinylsilane,
(Dimethylamino) dibutylvinylsilane, (ethylmethylamino) dibutylvinylsilane, (diethylamino) dibutylvinylsilane, (ethyl-n-propylamino) dibutylvinylsilane, (ethylisopropylamino) dibutylvinylsilane, (di (n-propyl) amino) dibutyl Examples include vinylsilane, (diisopropylamino) dibutylvinylsilane, (n-butyl-n-propylamino) dibutylvinylsilane, (di (n-butyl) amino) dibutylvinylsilane, and the like.
As {di (trialkylsilyl) amino} dialkylvinylsilane, {di (trimethylsilyl) amino} dimethylvinylsilane, {di (t-butyldimethylsilyl) amino} dimethylvinylsilane, {di (trimethylsilyl) amino} diethylvinylsilane, {di (T-butyldimethylsilyl) amino} diethylvinylsilane and the like.
(Dialkylamino) dialkoxyalkylvinylsilane includes (dimethylamino) dimethoxymethylvinylsilane, (dimethylamino) dimethoxyethylvinylsilane, (dimethylamino) diethoxymethylvinylsilane, (dimethylamino) diethoxyethylvinylsilane, (diethylamino) dimethoxymethyl Examples thereof include vinylsilane, (diethylamino) dimethoxyethylvinylsilane, (diethylamino) diethoxymethylvinylsilane, (diethylamino) diethoxyethylvinylsilane, and the like.

Compounds in which two of X ^{4 to} X ⁶ are acyclic amino groups represented by the formula (Va) and one is a hydrocarbyl group or a substituted hydrocarbyl group include bis (dialkylamino) alkylvinylsilane, bis {di (trialkyl Silyl) amino} alkylvinylsilane, bis (dialkylamino) alkoxyalkylvinylsilane, and the like.
Examples of bis (dialkylamino) alkylvinylsilane include bis (dimethylamino) methylvinylsilane, bis (ethylmethylamino) methylvinylsilane, bis (diethylamino) methylvinylsilane, bis (ethyl-n-propylamino) methylvinylsilane, and bis (ethylisopropyl). Amino) methylvinylsilane, bis (di (n-propyl) amino) methylvinylsilane, bis (diisopropylamino) methylvinylsilane, bis (n-butyl-n-propylamino) methylvinylsilane, bis (di (n-butyl) amino) Methyl vinyl silane,
Bis (dimethylamino) ethylvinylsilane, bis (ethylmethylamino) ethylvinylsilane, bis (diethylamino) ethylvinylsilane, bis (ethyl-n-propylamino) ethylvinylsilane, bis (ethylisopropylamino) ethylvinylsilane, bis (di (n -Propyl) amino) ethylvinylsilane, bis (diisopropylamino) ethylvinylsilane, bis (n-butyl-n-propylamino) ethylvinylsilane, bis (di (n-butyl) amino) ethylvinylsilane,
Bis (dimethylamino) propylvinylsilane, bis (ethylmethylamino) propylvinylsilane, bis (diethylamino) propylvinylsilane, bis (ethyl-n-propylamino) propylvinylsilane, bis (ethylisopropylamino) propylvinylsilane, bis (di (n -Propyl) amino) propylvinylsilane, bis (diisopropylamino) propylvinylsilane, bis (n-butyl-n-propylamino) propylvinylsilane, bis (di (n-butyl) amino) propylvinylsilane,
Bis (dimethylamino) butylvinylsilane, bis (ethylmethylamino) butylvinylsilane, bis (diethylamino) butylvinylsilane, bis (ethyl-n-propylamino) butylvinylsilane, bis (ethylisopropylamino) butylvinylsilane, bis (di (n -Propyl) amino) butylvinylsilane, bis (diisopropylamino) butylvinylsilane, bis (n-butyl-n-propylamino) butylvinylsilane, bis (di (n-butyl) amino) butylvinylsilane, and the like.
As bis {di (trialkylsilyl) amino} alkylvinylsilane, bis {di (trimethylsilyl) amino} methylvinylsilane, bis {di (t-butyldimethylsilyl) amino} methylvinylsilane, bis {di (trimethylsilyl) amino} ethyl Examples include vinyl silane and bis {di (t-butyldimethylsilyl) amino} ethyl vinyl silane.
Examples of bis (dialkylamino) alkoxyalkylvinylsilane include bis (dimethylamino) methoxymethylvinylsilane, bis (dimethylamino) methoxyethylvinylsilane, bis (dimethylamino) ethoxymethylvinylsilane, bis (dimethylamino) ethoxyethylvinylsilane,
Examples thereof include bis (diethylamino) methoxymethylvinylsilane, bis (diethylamino) methoxyethylvinylsilane, bis (diethylamino) ethoxymethylvinylsilane, and bis (diethylamino) ethoxyethylvinylsilane.

Examples of the compound in which three of X ^{4 to} X ⁶ are acyclic amino groups represented by the formula (Va) include tri (dialkylamino) vinylsilane.
For example, tri (dimethylamino) vinylsilane, tri (ethylmethylamino) vinylsilane, tri (diethylamino) vinylsilane, tri (ethylpropylamino) vinylsilane, tri (dipropylamino) vinylsilane, tri (butylpropylamino) vinylsilane Can do.

Compounds in which two of X ^{4 to} X ⁶ are cyclic amino groups represented by the formula (Va) and one is a hydrocarbyl group or a substituted hydrocarbyl group include bis (morpholino) methylvinylsilane, bis (piperidino) methylvinylsilane, bis (4,5-dihydroimidazolyl) methylvinylsilane, bis (hexamethyleneimino) methylvinylsilane and the like can be mentioned.

As the vinyl compound represented by the formula (V) in which two of X ⁴ , X ⁵ and X ⁶ are groups represented by the formula (Va), preferably two of X ⁴ , X ⁵ and X ⁶ are acyclic. A vinyl compound that is an amino group, and is preferably bis (dialkylamino) alkylvinylsilane, more preferably bis (dimethylamino), from the viewpoints of low fuel consumption, wet grip performance, wear resistance, and handling stability. ) Methyl vinyl silane, bis (diethylamino) methyl vinyl silane, bis (di (n-propyl) amino) methyl vinyl silane, bis (di (n-butyl) amino) methyl vinyl silane. Among these, bis (diethylamino) methylvinylsilane and bis (di (n-butyl) amino) methylvinylsilane are preferable from the viewpoint of availability of the compound.

In (Step A), polymerization may be performed by combining the conjugated diene and the vinyl compound represented by the formula (V) with another monomer. Examples of other monomers include aromatic vinyl, vinyl nitrile, and unsaturated carboxylic acid ester. Examples of the aromatic vinyl include styrene, α-methylstyrene, vinyl toluene, vinyl naphthalene, divinyl benzene, trivinyl benzene, and divinyl naphthalene. Examples of the vinyl nitrile include acrylonitrile, and examples of the unsaturated carboxylic acid ester include methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate. Among these, aromatic vinyl is preferable, and styrene is more preferable.

Polymerization in (Step A) is an agent that adjusts the vinyl bond amount of the conjugated diene unit, and an agent that adjusts the distribution of constituent units based on monomers other than the conjugated diene unit and the conjugated diene in the conjugated diene polymer chain. (Hereinafter collectively referred to as “regulator”) or the like. Examples of such agents include ether compounds, tertiary amines, and phosphine compounds. Examples of the ether compound include cyclic ethers such as tetrahydrofuran, tetrahydropyran, and 1,4-dioxane; aliphatic monoethers such as diethyl ether and dibutyl ether; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, and diethylene glycol diethyl ether. And aliphatic diethers such as diethylene glycol dibutyl ether; aromatic ethers such as diphenyl ether and anisole. Examples of the tertiary amine include triethylamine, tripropylamine, tributylamine, N, N, N ′, N′-tetramethylethylenediamine, N, N-diethylaniline, pyridine, quinoline and the like. Examples of the phosphine compound include trimethylphosphine, triethylphosphine, triphenylphosphine, and the like. These may be used alone or in combination of two or more.

The polymerization temperature in (Step A) is usually 25 to 100 ° C, preferably 35 to 90 ° C. More preferably, it is 50-80 degreeC. The polymerization time is usually 10 minutes to 5 hours.

In (Step B), the amount of the silicon compound having the group represented by the formula (II) and / or the group represented by the formula (III) to be brought into contact with the polymer prepared in the step A is In terms of moles of silicon atoms, particularly silicon atoms having a group represented by formula (IV), it is usually 0.1 to 3 moles per mole of alkali metal derived from an alkali metal catalyst, preferably 0. 0.5 to 2 mol, and more preferably 0.6 to 1.5 mol.

In (Step B), the temperature at which the polymer prepared in Step A is brought into contact with the silicon compound having a group represented by the formula (II) and / or a group represented by the formula (III) is usually 25 to 25%. 100 ° C, preferably 35 to 90 ° C. More preferably, it is 50-80 degreeC. The contact time is usually 60 seconds to 5 hours, preferably 5 minutes to 1 hour, more preferably 15 minutes to 1 hour.

In the production method of the present invention, if necessary, a coupling agent may be added to the hydrocarbon solution of the conjugated diene polymer from the start of the polymerization of the monomer by the alkali metal catalyst to the termination of the polymerization. An example of the coupling agent is a compound represented by the following formula (VI).
R ⁴¹ _a ML _4-a (VI)
(In the formula, R ⁴¹ represents an alkyl group, an alkenyl group, a cycloalkenyl group or an aromatic residue, M represents a silicon atom or a tin atom, L represents a halogen atom or a hydrocarbyloxy group, and a represents 0-2. Represents an integer.)
Here, the aromatic residue represents a monovalent group obtained by removing hydrogen bonded to an aromatic ring from an aromatic hydrocarbon.

As the coupling agent represented by the formula (VI), silicon tetrachloride, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, tin tetrachloride, methyltrichlorotin, dimethyldichlorotin, trimethylchlorotin, tetramethoxysilane, methyl Examples include trimethoxysilane, dimethoxydimethylsilane, methyltriethoxysilane, ethyltrimethoxysilane, dimethoxydiethylsilane, diethoxydimethylsilane, tetraethoxysilane, ethyltriethoxysilane, and diethoxydiethylsilane.

The addition amount of the coupling agent is preferably 0.03 mol or more, more preferably 0.05 mol or more, from the viewpoint of processability of the conjugated diene polymer per 1 mol of alkali metal derived from the alkali metal catalyst. is there. Moreover, from a viewpoint of low fuel consumption, Preferably it is 0.4 mol or less, More preferably, it is 0.3 mol or less.

Conjugated diene polymers can be collected by known recovery methods, for example, (1) a method of adding a coagulant to a hydrocarbon solution of a conjugated diene polymer, and (2) adding steam to a hydrocarbon solution of a conjugated diene polymer. By this method, the conjugated diene polymer can be recovered from the hydrocarbon solution. The recovered conjugated diene polymer may be dried by a known dryer such as a band dryer or an extrusion dryer.

Moreover, in the manufacturing method of the said conjugated diene polymer, it is preferable to perform the process which substitutes the group represented by the formula (Ia) of a polymer by a hydroxyl group by hydrolysis etc. The treatment may be performed in the state of the polymer alone or in the state of the composition as described below. Examples of the hydrolysis method include known methods such as a method by steam stripping. The above-described processing, the X ¹ to X ³ in the formula (I) may be a hydroxyl group, fuel economy, wet grip performance, wear resistance and steering stability can be further improved with good balance.

The conjugated diene polymer can be used in the rubber composition of the present invention as a rubber component, and is preferably used in combination with other rubber components and additives.

Examples of other rubber components include conventional styrene-butadiene copolymer rubber, polybutadiene rubber (BR), butadiene-isoprene copolymer rubber, and butyl rubber. Moreover, natural rubber (NR), an ethylene-propylene copolymer, an ethylene-octene copolymer, and the like can be given. Two or more of these rubber components may be used in combination. Among them, it is preferable to use NR and / or BR, and it is more preferable to use both components of NR and BR in terms of improving fuel economy, wet grip performance, wear resistance and steering stability in a well-balanced manner. preferable.

The content of the conjugated diene polymer in 100% by mass of the rubber component is 5% by mass or more, preferably 10% by mass or more, more preferably 30% by mass or more, and further preferably 50% by mass or more. When the content of the conjugated diene polymer is less than 5% by mass, there is a tendency that an improvement effect of low fuel consumption is difficult to obtain. The content of the conjugated diene polymer is preferably 90% by mass or less, more preferably 80% by mass or less, and still more preferably 70% by mass or less. When the content of the conjugated diene polymer exceeds 90% by mass, the wear resistance is lowered and the cost tends to be high.

The NR is not particularly limited. For example, SIR20, RSS # 3, TSR20, deproteinized natural rubber (DPNR), high-purity natural rubber (HPNR), etc., which are common in the tire industry can be used.

The content of NR in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more. If it is less than 5% by mass, the wear resistance tends to decrease. The NR content is preferably 70% by mass or less, more preferably 60% by mass or less. If it exceeds 70% by mass, the wet grip performance tends to decrease.

It is not particularly limited as BR, for example, BR1220 manufactured by Nippon Zeon Co., Ltd., BR130B manufactured by Ube Industries, Ltd., BR150B having high cis content such as BR150B, VCR412 manufactured by Ube Industries, Ltd., VCR617, etc. Commonly used in the tire industry, such as BR containing syndiotactic polybutadiene crystals, can be used.

The content of BR in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more. If it is less than 5% by mass, the wear resistance tends to decrease. The BR content is preferably 60% by mass or less, more preferably 50% by mass or less. If it exceeds 60% by mass, the wet grip performance tends to decrease.

The total content of NR and BR in 100% by mass of the rubber component is preferably 10% by mass or more, more preferably 20% by mass or more, and further preferably 30% by mass or more. If it is less than 10% by mass, the wear resistance tends to decrease. The total content is preferably 70% by mass or less, more preferably 50% by mass or less. If it exceeds 70% by mass, the wet grip performance tends to decrease.

The rubber composition of the present invention contains silica (1) having a nitrogen adsorption specific surface area of 100 m ² / g or less and silica (2) having a nitrogen adsorption specific surface area of 180 m ² / g or more. By blending silica (1) and (2) together with the conjugated diene polymer, silica (1) and (2) are well dispersed, resulting in low fuel consumption, wet grip performance, wear resistance and handling stability. Can be improved in a well-balanced and high-dimensional manner.

The nitrogen adsorption specific surface area (N ₂ SA) of silica (1) is 100 m ² / g or less, preferably 80 m ² / g or less, more preferably 60 m ² / g or less. When it exceeds 100 m < ² > / g, there exists a possibility that the effect by combined use of a silica (1) and (2) may not fully be acquired. Further, N ₂ SA of silica (1) is preferably 20 m ² / g or more, more preferably 30 m ² / g or more. If it is less than 20 m < ² > / g, there exists a possibility that fracture strength may fall or it may become impossible to fully improve abrasion resistance and steering stability.
The nitrogen adsorption specific surface area of silica is a value measured by the BET method according to ASTM D3037-81.

Silica (1) is not particularly limited as long as the nitrogen adsorption specific surface area is 100 m ² / g or less, and examples thereof include Ultrazil 360 manufactured by Degussa, Z40 manufactured by Rhodia, and RP80 manufactured by Rhodia. Can be used. These may be used alone or in combination of two or more.

The content of silica (1) 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. If it is less than 5 parts by mass, the fuel economy may not be sufficiently improved. The content of silica (1) is preferably 80 parts by mass or less, more preferably 60 parts by mass or less. If it exceeds 80 parts by mass, the fuel efficiency is good, but the breaking strength tends to decrease.

N ₂ SA of silica (2) is 180 m ² / g or more, preferably 190 m ² / g or more, more preferably 200 m ² / g or more. If N ₂ SA of silica (2) is less than 180 m ² / g, the effect of the combined use of silica (1) and (2) may not be sufficiently obtained. Also, _N 2 SA of the silica (2) is preferably 300 meters ² / g, more preferably at most 240 m ² / g. If N ₂ SA of silica (2) exceeds 300 m ² / g, processability may be deteriorated or fuel economy may not be sufficiently improved.

The silica (2) is not particularly limited as long as the silica has a nitrogen adsorption specific surface area of 180 m ² / g or more, and for example, Zeosyl 1205MP manufactured by Rhodia can be used. These may be used alone or in combination of two or more.

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. If the amount is less than 5 parts by mass, sufficient steering stability may not be obtained. Further, the content of silica (2) is preferably 90 parts by mass or less, more preferably 70 parts by mass or less. If it exceeds 90 parts by mass, the steering stability is good, but the workability tends to deteriorate.

The total content of silica (1) and (2) is 30 parts by mass or more, preferably 40 parts by mass or more, more preferably 50 parts by mass or more with respect to 100 parts by mass of the rubber component. If it is less than 30 mass parts, there exists a possibility that the sufficient reinforcement effect by the mixing | blending of silica (1) and (2) may not be acquired. Moreover, this total content is 150 mass parts or less, Preferably it is 120 mass parts or less, More preferably, it is 100 mass parts or less. If it exceeds 150 parts by mass, it will be difficult to uniformly disperse silica (1) and (2), and processability and fuel economy will tend to deteriorate.

The total content of silica (1) and (2) in a total of 100% by mass of silica (1) and (2) and carbon black is preferably 60% by mass or more, more preferably 85% by mass or more, Preferably it is 98 mass% or less, More preferably, it is 95 mass% or less. If it is in the said range, low-fuel-consumption property, wet-grip performance, abrasion resistance, and steering stability can be improved with a high degree of balance.

The content of silica (1) and the content of silica (2) preferably satisfy the following formula. Thereby, silica (1) and (2) can be disperse | distributed more favorably.
[Content of silica (1)] × 0.2 ≦ [Content of silica (2)] ≦ [Content of silica (1)] × 6.5

The content of silica (2) is preferably 0.2 times or more, more preferably 0.3 times or more, still more preferably 0.4 times or more with respect to the content of silica (1). If it is less than 0.2 times, the steering stability may be lowered. Further, the content of silica (2) is preferably 6.5 times or less, more preferably 5 times or less, and still more preferably 4 times or less with respect to the content of silica (1). If it exceeds 6.5 times, the fuel efficiency may be deteriorated.

The rubber composition of the present invention preferably contains a silane coupling agent together with silica (1) and (2). As the silane coupling agent, bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) disulfide, 3-trimethoxysilylpropylbenzothiazolyltetra, from the viewpoint of improving reinforcing properties, etc. Preference is given to using sulfides.

The content of the silane coupling agent is preferably 4 parts by mass or more, more preferably 8 parts by mass or more with respect to 100 parts by mass of the total content of silica. If it is less than 4 parts by mass, the fracture strength tends to be greatly reduced. Moreover, the content of the silane coupling agent is preferably 15 parts by mass or less, more preferably 10 parts by mass or less. When it exceeds 15 parts by mass, there is a tendency that an effect commensurate with the increase in cost cannot be obtained.

Known additives can be used, such as sulfur vulcanizing agents; thiazole vulcanization accelerators, thiuram vulcanization accelerators, sulfenamide vulcanization accelerators, guanidine vulcanization accelerators. Vulcanization accelerators such as stearic acid and zinc oxide; organic peroxides; fillers such as carbon black, calcium carbonate, talc, alumina, clay, aluminum hydroxide and mica; Examples include processing aids such as lubricants; anti-aging agents.

Examples of the carbon black include furnace black (furness carbon black) such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF and ECF; acetylene black (acetylene carbon black); FT and Examples thereof include thermal black (thermal carbon black) such as MT; channel black (channel carbon black) such as EPC, MPC and CC; graphite and the like. These can be used alone or in combination of two or more. From the viewpoint that fuel economy, wet grip performance, wear resistance and handling stability can be improved in a high level and in a well-balanced manner, the carbon black content is preferably 1 part by mass or more with respect to 100 parts by mass of the rubber component. More preferably, it is 3 parts by mass or more, preferably 30 parts by mass or less, more preferably 10 parts by mass or less.

Nitrogen adsorption specific surface area _(N 2 SA) of carbon black is preferably ^{5 m} 2 / g or more, more preferably ^{30 m} 2 / g or more, more preferably ^{50 m} 2 / g or more, particularly preferably be ^70m 2 / g or more , Preferably 250 m ² / g or less, more preferably 200 m ² / g or less, still more preferably 150 m ² / g or less. Moreover, the dibutyl phthalate (DBP) absorption amount of carbon black is preferably 5 ml / 100 g or more, more preferably 80 ml / 100 g or more, preferably 300 ml / 100 g or less, more preferably 180 ml / 100 g or less. If the N ₂ SA or DBP absorption amount of the carbon black is less than the lower limit of the above range, the reinforcing effect tends to be small and the wear resistance tends to decrease. If the upper limit of the above range is exceeded, dispersibility is poor and hysteresis loss increases. There is a tendency for fuel efficiency to decrease. The nitrogen adsorption specific surface area is measured according to ASTM D4820-93, and the DBP absorption is measured according to ASTM D2414-93. As a commercially available product, Tokai Carbon Co., Ltd. trade name SHIEST 6, SEAST 7HM, SEAST KH, Evonik Degussa trade name CK3, Special Black 4A, etc. can be used.

Examples of the extending oil include aromatic mineral oil (viscosity specific gravity constant (VGC value) 0.900 to 1.049), naphthenic mineral oil (VGC value 0.850 to 0.899), paraffinic mineral oil (VGC value 0.790 to 0.849), and the like. The polycyclic aromatic content of the extender oil is preferably less than 3% by mass, more preferably less than 1% by mass. The polycyclic aromatic content is measured according to the British Petroleum Institute 346/92 method. Moreover, the aromatic compound content (CA) of the extending oil is preferably 20% by mass or more. These extending oils may be used in combination of two or more.

Examples of the vulcanization accelerator include thiazole vulcanization accelerators such as 2-mercaptobenzothiazole, dibenzothiazyl disulfide, and N-cyclohexyl-2-benzothiazylsulfenamide; tetramethylthiuram monosulfide, tetramethylthiuram Thiuram vulcanization accelerators such as disulfide; N-cyclohexyl-2-benzothiazole sulfenamide, Nt-butyl-2-benzothiazole sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, N -Sulfenamide vulcanization accelerators such as oxyethylene-2-benzothiazole sulfenamide, N, N'-diisopropyl-2-benzothiazole sulfenamide; diphenylguanidine, diortolylguanidine, orthotolylbiguanidine, etc. No Can be mentioned blurring based vulcanization accelerator, its amount is preferably from 0.1 to 5 parts by mass with respect to 100 parts by mass of the rubber component, more preferably from 0.2 to 3 parts by weight.

As a method for producing a rubber composition by blending the conjugated diene polymer with other rubber components or additives, a known method, for example, using a known mixer such as a roll or a banbury for each component. A kneading method can be used.

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. A composition containing a vulcanizing agent and a vulcanization accelerator is usually used after 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 excellent in the balance of low fuel consumption, wet grip performance, wear resistance, and steering stability, and can provide a remarkable improvement effect of these performances.

The rubber composition of the present invention can be suitably used for each member of a tire, and can be particularly suitably used for a tread.

The pneumatic tire of the present invention is produced by a usual method using the rubber composition. That is, a rubber composition containing various additives as necessary is extruded in accordance with the shape of the tread of the tire at an unvulcanized stage, molded by a normal method on a tire molding machine, etc. The tire members are bonded together to form an unvulcanized tire. This unvulcanized tire can be heated and pressurized in a vulcanizer to produce the pneumatic tire of the present invention.

The pneumatic tire of the present invention can be suitably used as a tire for passenger cars and a tire for trucks and buses (heavy load tire).

Hereinafter, the present invention will be described by way of examples.
The physical properties were evaluated by the following method.

1. Vinyl bond amount (unit: mol%)
The amount of vinyl bonds in the polymer was determined from the absorption intensity near 910 cm ^−1, which is the absorption peak of the vinyl group, by infrared spectroscopy.

2. Styrene unit content (unit: mass%)
According to JIS K6383 (1995), the content of styrene units in the polymer was determined from the refractive index.

3. Molecular weight distribution (Mw / Mn)
The weight average molecular weight (Mw) and number average molecular weight (Mn) were measured by gel permeation chromatography (GPC) method under the following conditions (1) to (8). And the molecular weight distribution (Mw / Mn) of the polymer was calculated | required from measured Mw and Mn.
(1) Apparatus: HLC-8020 manufactured by Tosoh Corporation
(2) Separation column: Tosoh GMH-XL (two in series)
(3) Measurement temperature: 40 ° C
(4) Carrier: Tetrahydrofuran (5) Flow rate: 0.6 mL / min (6) Injection volume: 5 μL
(7) Detector: Differential refraction (8) Molecular weight standard: Standard polystyrene

4). Using a rolling resistance rolling resistance tester, rolling resistance was measured when the test tire was run at a rim (15 × 6 JJ), internal pressure (230 kPa), load (3.43 kN), and speed (80 km / h). . And the rolling resistance index | exponent of the comparative example 1 was set to 100, and the rolling resistance of each mixing | blending was displayed as an index | exponent with the formula shown below. Larger values indicate lower rolling resistance and better fuel efficiency.
(Rolling resistance index) = (Rolling resistance of Comparative Example 1) / (Rolling resistance of each formulation) × 100

5. Wet grip performance Test tires manufactured were mounted on all wheels of a vehicle (domestic FF2000cc), and the braking distance from an initial speed of 100 km / h was measured on a wet asphalt road surface. And the wet grip performance index | exponent of the comparative example 1 was set to 100, and the wet skid performance (wet grip performance) of each mixing | blending was displayed as an index | exponent with the calculation formula shown below. Larger values indicate better wet grip performance.
(Wet grip performance index) = (Brake distance of Comparative Example 1) / (Brake distance of each formulation) × 100

6). Wear-proof manufactured test tires were mounted on all the wheels of a vehicle (domestic FF2000cc) and traveled on an actual vehicle, and changes in the groove depth of the tread pattern before and after traveling 30000 km were measured. Then, assuming that the abrasion resistance index of Comparative Example 1 was 100, the change in the groove depth of each formulation was displayed as an index according to the following calculation formula. It shows that it is excellent in abrasion resistance, so that a numerical value is large.
(Abrasion resistance index) = (Change in groove depth of Comparative Example 1) / (Change in groove depth of each formulation) × 100

7). Steering Stability Manufactured test tires were mounted on all wheels of a vehicle (domestic FF2000cc) and run on a real vehicle, and steering stability was evaluated by sensory evaluation of the driver. In the evaluation, the comparative example 1 was set to 6 points, and a relative evaluation was performed with a maximum of 10 points. It shows that it is excellent in steering stability, so that the rating of steering stability is large.

Production Example 1 (Synthesis of Polymer 1)
It washed 20 liter stainless steel polymerization reactor, and dried, flushed with dry nitrogen, hexane (specific gravity 0.68g ^/ cm 3) 10.2kg, 1,3- butadiene 547 g, styrene 173 g, tetrahydrofuran 6. 1 ml and ethylene glycol diethyl ether 5.0 ml were charged into the polymerization reactor. Next, 16.0 mmol of bis (diethylamino) methylvinylsilane and 18.5 mmol of n-butyllithium were added as a cyclohexane solution and an n-hexane solution, respectively, to initiate polymerization.
The stirring rate was 130 rpm, the temperature in the polymerization reactor was 65 ° C., and 1,3-butadiene and styrene were copolymerized for 3 hours while continuously supplying the monomer into the polymerization reactor. The supply amount of 1,3-butadiene in the total polymerization was 821 g, and the supply amount of styrene was 259 g.
Next, the obtained polymer solution was stirred at a stirring speed of 130 rpm, and 4.0 mmol of 1,3,5-tris (3-trimethoxysilylpropyl) isocyanurate was added and stirred for 15 minutes. 20 ml of hexane solution containing 0.80 ml of methanol was added to the polymer solution, and the polymer solution was further stirred for 5 minutes.

2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumilyzer GM) was added to the polymer solution. 8 g, 0.9 g of pentaerythrityl tetrakis (3-laurylthiopropionate) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumilizer TP-D) was added, and then the polymer was removed from the polymer solution by steam stripping. 1 was recovered. The evaluation results of the polymer 1 are shown in Table 1. In addition, the content of the structural unit represented by the formula (I) in the polymer calculated from the input amount and the supply amount of the raw material into the polymerization reactor is 0.009 mmol / g polymer per polymer unit mass. there were.

Production Example 2 (Synthesis of Polymer 2)
It washed 20 liter stainless steel polymerization reactor, and dried, flushed with dry nitrogen, hexane (specific gravity 0.68g ^/ cm 3) 10.2kg, 1,3- butadiene 547 g, styrene 173 g, tetrahydrofuran 6. 1 ml and ethylene glycol diethyl ether 5.0 ml were charged into the polymerization reactor. Next, 17.3 mmol of n-butyllithium was added as an n-hexane solution, and 1,3-butadiene and styrene were copolymerized for 1 hour. During the polymerization, the stirring speed was 130 rpm, the temperature in the polymerization reactor was 65 ° C., and the monomer was continuously fed into the polymerization reactor.
After the 1-hour polymerization, 14.4 mmol of bis (diethylamino) methylvinylsilane was added as a cyclohexane solution, and the mixture was charged into the polymerization reactor under the conditions of a stirring speed of 130 rpm and a polymerization reactor temperature of 65 ° C.
Next, the monomer was continuously supplied into the polymerization reactor, and 1,3-butadiene and styrene were copolymerized for 0.5 hour. During the polymerization, the stirring speed was 130 rpm, and the temperature in the polymerization reactor was 65 ° C.
After the 0.5 hour polymerization, 14.4 mmol of bis (diethylamino) methylvinylsilane was added as a cyclohexane solution, and the mixture was charged into the polymerization reactor under the conditions of a stirring speed of 130 rpm and a polymerization reactor internal temperature of 65 ° C.
Next, the monomer was continuously supplied into the polymerization reactor, and 1,3-butadiene and styrene were copolymerized for 0.5 hour. During the polymerization, the stirring speed was 130 rpm, and the temperature in the polymerization reactor was 65 ° C.
After the 0.5 hour polymerization, 14.4 mmol of bis (diethylamino) methylvinylsilane was added as a cyclohexane solution, and the mixture was charged into the polymerization reactor under the conditions of a stirring speed of 130 rpm and a polymerization reactor internal temperature of 65 ° C.
Next, the monomer was continuously supplied into the polymerization reactor, and 1,3-butadiene and styrene were copolymerized for 0.5 hour. During the polymerization, the stirring speed was 130 rpm, and the temperature in the polymerization reactor was 65 ° C. The supply amount of 1,3-butadiene in the total polymerization was 821 g, and the supply amount of styrene was 259 g.
Next, the obtained polymer solution was stirred at a stirring speed of 130 rpm, 3.6 mmol of 1,3,5-tris (3-trimethoxysilylpropyl) isocyanurate was added and stirred for 15 minutes. 20 ml of hexane solution containing 0.80 ml of methanol was added to the polymer solution, and the polymer solution was further stirred for 5 minutes.

2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumilyzer GM) was added to the polymer solution. 8 g, 0.9 g of pentaerythrityl tetrakis (3-laurylthiopropionate) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumilizer TP-D) was added, and then the polymer was removed from the polymer solution by steam stripping. 2 was recovered. The evaluation results of Polymer 2 are shown in Table 1. In addition, the content of the structural unit represented by the formula (I) in the polymer calculated from the input amount and the supply amount of the raw material into the polymerization reactor is 0.024 mmol / g polymer per polymer unit mass. there were.

Production Example 3 (Synthesis of Polymer 3)
It washed 20 liter stainless steel polymerization reactor, and dried, flushed with dry nitrogen, hexane (specific gravity 0.68g ^/ cm 3) 10.2kg, 1,3- butadiene 547 g, styrene 173 g, tetrahydrofuran 6. 1 ml and ethylene glycol diethyl ether 5.0 ml were charged into the polymerization reactor. Next, 16.0 mmol of bis (diethylamino) methylvinylsilane and 18.5 mmol of n-butyllithium were added as a cyclohexane solution and an n-hexane solution, respectively, to initiate polymerization.
The stirring rate was 130 rpm, the temperature in the polymerization reactor was 65 ° C., and 1,3-butadiene and styrene were copolymerized for 3 hours while continuously supplying the monomer into the polymerization reactor. The supply amount of 1,3-butadiene in the total polymerization was 821 g, and the supply amount of styrene was 259 g.
Next, the obtained polymer solution was stirred at a stirring speed of 130 rpm, and 4.0 mmol of 1,3,5-tris (3-trimethoxysilylpropyl) isocyanurate was added and stirred for 15 minutes. 20 ml of hexane solution containing 0.80 ml of methanol was added to the polymer solution, and the polymer solution was further stirred for 5 minutes.

2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumilyzer GM) was added to the polymer solution. 8 g, 0.9 g of pentaerythrityltetrakis (3-laurylthiopropionate) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumilizer TP-D) was added, and then the polymer solution was stirred at room temperature for 24 hours. Evaporated and further dried under reduced pressure at 55 ° C. for 12 hours to obtain a polymer 3. The evaluation results of the polymer 3 are shown in Table 1. In addition, the content of the structural unit represented by the formula (I) in the polymer calculated from the input amount and the supply amount of the raw material into the polymerization reactor is 0.009 mmol / g polymer per polymer unit mass. there were.

Production Example 4 (Synthesis of Polymer 4)
It washed 20 liter stainless steel polymerization reactor, and dried, flushed with dry nitrogen, hexane (specific gravity 0.68g ^/ cm 3) 10.2kg, 1,3- butadiene 547 g, styrene 173 g, tetrahydrofuran 6. 1 ml and ethylene glycol diethyl ether 5.0 ml were charged into the polymerization reactor. Next, 16.0 mmol of bis (diethylamino) methylvinylsilane and 18.5 mmol of n-butyllithium were added as a cyclohexane solution and an n-hexane solution, respectively, to initiate polymerization.
The stirring rate was 130 rpm, the temperature in the polymerization reactor was 65 ° C., and 1,3-butadiene and styrene were copolymerized for 3 hours while continuously supplying the monomer into the polymerization reactor. The supply amount of 1,3-butadiene in the total polymerization was 821 g, and the supply amount of styrene was 259 g.
Next, the obtained polymer solution was stirred at a stirring speed of 130 rpm, and 4.0 mmol of 3- (methoxy) propyltrimethoxysilane was added and stirred for 15 minutes. 20 ml of hexane solution containing 0.80 ml of methanol was added to the polymer solution, and the polymer solution was further stirred for 5 minutes.

2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumilyzer GM) was added to the polymer solution. 8 g, 0.9 g of pentaerythrityl tetrakis (3-laurylthiopropionate) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumilizer TP-D) was added, and then the polymer was removed from the polymer solution by steam stripping. 4 was recovered. The evaluation results of the polymer 4 are shown in Table 1. In addition, the content of the structural unit represented by the formula (I) in the polymer calculated from the input amount and the supply amount of the raw material into the polymerization reactor is 0.009 mmol / g polymer per polymer unit mass. there were.

Production Example 5 (Synthesis of Polymer 5)
It washed 20 liter stainless steel polymerization reactor, and dried, flushed with dry nitrogen, hexane (specific gravity 0.68g ^/ cm 3) 10.2kg, 1,3- butadiene 547 g, styrene 173 g, tetrahydrofuran 6. 1 ml and ethylene glycol diethyl ether 5.0 ml were charged into the polymerization reactor. Next, 18.5 mmol of n-butyllithium was added as an n-hexane solution to initiate polymerization.
The stirring rate was 130 rpm, the temperature in the polymerization reactor was 65 ° C., and 1,3-butadiene and styrene were copolymerized for 3 hours while continuously supplying the monomer into the polymerization reactor. The supply amount of 1,3-butadiene in the total polymerization was 821 g, and the supply amount of styrene was 259 g.
Next, 20 ml of hexane solution containing 0.80 ml of methanol was added to the polymer solution, and the polymer solution was further stirred for 5 minutes.

2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumilyzer GM) was added to the polymer solution. 8 g, 0.9 g of pentaerythrityl tetrakis (3-laurylthiopropionate) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumilizer TP-D) was added, and then the polymer was removed from the polymer solution by steam stripping. 5 was recovered. The evaluation results of the polymer 5 are shown in Table 1. In addition, since the polymer 5 did not use the compound represented by Formula (V) at the time of a synthesis | combination, it did not contain the structural unit represented by Formula (I).

Below, various chemical | medical agents used by the Example and the comparative example are demonstrated.
Natural rubber: RSS # 3
Butadiene rubber: Ubepol BR150B manufactured by Ube Industries, Ltd.
Polymers 1 to 5: Production examples 1 to 5
Silica 1: Ultrasil 360 manufactured by Degussa (N ₂ SA: 50 m ² / g)
Silica 2: Zeosyl 1205MP (N ₂ SA: 200 m ² / g) manufactured by Rhodia
Silane coupling agent: Si75 manufactured by Degussa
Carbon black: Dia Black N339 manufactured by Mitsubishi Chemical Corporation (N ₂ SA: 96 m ² / g, DBP absorption: 124 ml / 100 g)
Oil: Diana Process Oil AH-25 manufactured by Idemitsu Kosan Co., Ltd.
Anti-aging agent: Antigen 3C manufactured by Sumitomo Chemical Co., Ltd.
Stearic acid: Beads manufactured by NOF Corporation Zinc stearate zinc oxide: Zinc oxide wax manufactured by Mitsui Kinzoku Mining Co., Ltd .: Sunnock N manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Sulfur: Powder sulfur vulcanization accelerator manufactured by Tsurumi Chemical Industry Co., Ltd. 1: Soxinol CZ manufactured by Sumitomo Chemical Co., Ltd.
Vulcanization accelerator 2: Soxinol D manufactured by Sumitomo Chemical Co., Ltd.

(Examples and Comparative Examples)
According to the composition shown in Table 2, materials other than sulfur and a vulcanization accelerator were kneaded for 3 minutes at 150 ° C. using a 1.7 L Banbury mixer manufactured by Kobe Steel Co., Ltd. Obtained. Next, sulfur and a vulcanization accelerator were added to the obtained kneaded product, and kneaded for 3 minutes at 80 ° C. using an open roll to obtain an unvulcanized rubber composition. The obtained unvulcanized rubber composition is molded into a tread shape and bonded together with other tire members on a tire molding machine to form an unvulcanized tire, and then vulcanized at 160 ° C. for 20 minutes for testing. A tire (size: 195 / 65R15) was produced.

The obtained test tire was used for evaluation by the above test method. Each test result is shown in Table 2.

As shown in Table 2, it has a structural unit based on a conjugated diene and a structural unit represented by the above formula (I), and is represented by the group represented by the above formula (II) and / or the above formula (III). Implementation in which a polymer (polymers 1 to 4) whose ends are modified by a silicon compound having a group to be used and two types of silica (silica 1, 2) having a nitrogen adsorption specific surface area within a specific range Compared with the comparative example, the fuel efficiency, wet grip performance, wear resistance, and steering stability were synergistically improved in the examples, and these performances were obtained in a high level and in a well-balanced manner.

Claims (10)

Rubber component,
Silica (1) having a nitrogen adsorption specific surface area of 100 m ² / g or less;
Containing silica (2) having a nitrogen adsorption specific surface area of 180 m ² / g or more,
Of the 100% by mass of the rubber component, it has a structural unit based on a conjugated diene and a structural unit represented by the following formula (I), and a group represented by the following formula (II) and / or the following formula (III) The content of the conjugated diene polymer obtained by modifying at least one end of the polymer with a silicon compound having a group represented by:
The rubber composition, wherein the total content of the silica (1) and (2) with respect to 100 parts by mass of the rubber component is 30 to 150 parts by mass.

[Wherein, X ¹ , X ² and X ³ each independently represent a group represented by the following formula (Ia), a hydroxyl group, a hydrocarbyl group or a substituted hydrocarbyl group, and at least ^one of X ¹ , X ² and X ³ One is a group or a hydroxyl group represented by the following formula (Ia). ]

[Wherein, R ¹ and R ² independently denote a hydrocarbyl group having 1 to 6 carbon atoms, a substituted hydrocarbyl group having 1-6 carbon atoms, or a substituted silyl group, R ¹ and R ² may be bonded to form a ring structure with the nitrogen atom. ]

The rubber composition according to claim ^1, wherein R ¹ and R ^{2 in} the formula (Ia) are hydrocarbyl groups having 1 to 6 carbon atoms. The rubber composition according to claim 1 or 2, wherein ^two of X ¹ , X ² and X ^{3 in} the formula (I) are a group or a hydroxyl group represented by the formula (Ia). The rubber composition according to claim 1, wherein the silicon compound has a group represented by the following formula (IV).

[Wherein R ³ , R ⁴ and R ⁵ each independently represent a hydrocarbyl group having 1 to 4 carbon atoms or a hydrocarbyloxy group having 1 to 4 carbon atoms, and R ³ , R ⁴ and R 5 ^At least one of ⁵ is a hydrocarbyloxy group. ] The rubber composition according to claim 1, wherein the silicon compound has a group represented by the following formula (IIa).

[Wherein, m represents an integer of 1 to 10, and R ⁶ , R ⁷ and R ⁸ are each independently a hydrocarbyl group having 1 to 4 carbon atoms or a hydrocarbyloxy group having 1 to 4 carbon atoms. And at least one of R ⁶ , R ⁷ and R ⁸ is a hydrocarbyloxy group. ] The vinyl bond amount of the conjugated diene polymer is 10 mol% or more and 80 mol% or less, where the content of the structural unit based on the conjugated diene is 100 mol%. The rubber composition as described. The rubber composition according to claim 1, comprising natural rubber and / or butadiene rubber. The rubber composition according to claim 1, wherein the content of silica (1) and the content of silica (2) satisfy the following formula.
[Content of silica (1)] × 0.2 ≦ [Content of silica (2)] ≦ [Content of silica (1)] × 6.5 The rubber composition according to any one of claims 1 to 8, wherein the rubber composition is used as a rubber composition for a tread. The pneumatic tire produced using the rubber composition in any one of Claims 1-9.