JP2013014708A - Rubber composition and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition capable of improving fuel efficiency, wet grip performance and abrasion resistance, with satisfactory balance, and a pneumatic tire using the same.SOLUTION: There is provided a rubber composition containing a rubber component, silica, and a liquid resin having -20 to 20°C of softening point, containing, 5 mass% or more of a conjugated diene polymer having a constitutional unit based on a conjugated diene and a constitutional unit represented by formula (I), and having at least one modified end of the polymer, out of 100 mass% of the rubber component, and containing 5-150 pts.mass or more of silica per 100 pts.mass of the rubber component. In the formula (I), X, Xand Xrepresent respectively independently a group expressed by formula (Ia), hydroxy group, hydrocarbyl group or substituted hydrocarbyl group, and at least one of the X, Xand Xis the group expressed by the formula (Ia) or the hydroxy group. In the formula (Ia), Rand Rrepresent respectively independently 1-6C hydrocarbyl group, 1-6C substituted hydrocarbyl group, silyl group, or substituted silyl group, and the Rand Rmay be coupled to form a ring structure together with a nitrogen atom.

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 rubber composition for an automobile tire, a rubber composition containing a conjugated diene polymer such as polybutadiene or butadiene-styrene copolymer and a filler such as carbon black or silica is used.

As a method for improving fuel economy, for example, Patent Document 1 proposes a method using a diene rubber modified with an organosilicon compound containing an amino group and an alkoxy group. However, in recent years, further improvement in fuel efficiency has been demanded. In addition, the performance required for rubber compositions for automobile tires includes wet grip performance and wear resistance, but these performances are generally in contradiction to low fuel consumption. It was difficult to obtain a high dimension and good balance.

JP 2000-344955 A

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

［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。］

［式中、ｎは１〜１０の整数を表し、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り、Ａは窒素原子を有する官能基を表す。］ The present invention contains a rubber component, silica, and a liquid resin having a softening point of -20 to 20 ° C. Among 100% by mass of the rubber component, a structural unit based on a conjugated diene and represented by the following formula (I): The content of the conjugated diene polymer obtained by modifying at least one end of the polymer with the compound represented by the following formula (II) is 5% by mass or more, and the rubber component is 100% by mass. It is related with the rubber composition whose content of the said silica is 5-150 mass parts with respect to a part.

[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. ]

[Wherein n represents an integer of 1 to 10, and R ³ , R ⁴ and R ⁵ each independently represents 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 ³ , R ⁴ and R ⁵ is a hydrocarbyloxy group, and A represents a functional group having a 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^６及びＲ^７は、それぞれ独立に、窒素原子、酸素原子及びケイ素原子からなる原子群から選ばれる少なくとも１種の原子を有していてもよい炭素原子数が１〜６の基を表し、Ｒ^６及びＲ^７は結合して窒素原子と共に環構造を形成していてもよく、Ｒ^６及びＲ^７は窒素に二重結合で結合する同一の基であってもよい。］ A in formula (II) is preferably a group represented by the following formula (IIa).

[Wherein R ⁶ and R ⁷ each independently have 1 to 6 carbon atoms which may have at least one atom selected from the group consisting of a nitrogen atom, an oxygen atom and a silicon atom. R ⁶ and R ⁷ may be bonded to form a ring structure with the nitrogen atom, and R ⁶ and R ⁷ may be the same group bonded to the nitrogen by a double bond. ]

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 nitrogen adsorption specific surface area of a silica is 40-400 m < ² > / g.

The content of the liquid resin with respect to 100 parts by mass of the rubber component is preferably 1 to 40 parts by mass.

The liquid resin is preferably a coumarone indene resin.

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, silica, and a liquid resin having a specific softening point are blended, low fuel consumption, wet grip performance, and wear resistance are balanced. It is possible to provide a pneumatic tire that is well improved.

［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。］

［式中、ｎは１〜１０の整数を表し、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り、Ａは窒素原子を有する官能基を表す。］ 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), and at least one end of the polymer is modified by a compound represented by the following formula (II): A conjugated diene polymer, silica, and a liquid resin having a specific softening point.

[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. ]

[Wherein n represents an integer of 1 to 10, and R ³ , R ⁴ and R ⁵ each independently represents 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 ³ , R ⁴ and R ⁵ is a hydrocarbyloxy group, and A represents a functional group having a 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, an alkylene group such as a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group; an oxydialkylene group such as an oxydiethylene group and an oxydipropylene group; and —CH ₂ CH ₂ —NH—CH ₂ — 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. Moreover, it is preferable that at least one of X ¹ , X ^2, and X ³ is a hydroxyl group from the viewpoint that low fuel consumption, wet grip performance, and wear resistance can be obtained in a high-order and well-balanced manner, and X ¹ , X ² and It is more preferable that two or more of X ³ are hydroxyl groups, and it is still more preferable that ^{two of} X ¹ , X ² and X ³ are hydroxyl groups.

From the viewpoint of improving fuel economy, wet grip performance and wear resistance in a well-balanced manner, as the structural unit represented by the formula (I), ^{two of} X ¹ , X ² and X ³ are acyclic amino groups or hydroxyl groups. A structural unit is preferred. 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 preferably 0 per unit mass of the polymer from the viewpoint of improving fuel economy, wet grip performance and wear resistance in a balanced manner. 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.

［式中、ｎは１〜１０の整数を表し、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り、Ａは窒素原子を有する官能基を表す。］ The conjugated diene polymer is a polymer obtained by modifying at least one end of a polymer with a compound represented by the following formula (II).

[Wherein n represents an integer of 1 to 10, and R ³ , R ⁴ and R ⁵ each independently represents 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 ³ , R ⁴ and R ⁵ is a hydrocarbyloxy group, and A represents a functional group having a nitrogen atom. ]

R ³ , R ⁴ and R ^{5 in} formula (II) 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 At least one of R ⁵ is a hydrocarbyloxy group.

Examples of the hydrocarbyl group of R ³ , R ⁴ and R ⁵ include methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, sec-butyl groups, alkyl groups such as tert-butyl groups, and the like. Can do. ^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 , preferably, at least two of R ³ , R ⁴ and R ⁵ are hydrocarbyloxy groups from the viewpoint of improving fuel economy, wet grip performance and wear resistance in a balanced manner. More preferably, ^three of R ³ , R ⁴ and R ⁵ are hydrocarbyloxy groups.

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

A in the formula (II) is a functional group having a nitrogen atom, and examples thereof include an amino group, an isocyano group, a cyano group, a pyridyl group, a piperidyl group, a pyrazinyl group, and a morpholino group.

［式中、Ｒ^６及びＲ^７は、それぞれ独立に、窒素原子、酸素原子及びケイ素原子からなる原子群から選ばれる少なくとも１種の原子を有していてもよい炭素原子数が１〜６の基を表し、Ｒ^６及びＲ^７は結合して窒素原子と共に環構造を形成していてもよく、Ｒ^６及びＲ^７は窒素に二重結合で結合する同一の基であってもよい。］ A is preferably a group represented by the following formula (IIa).

[Wherein R ⁶ and R ⁷ each independently have 1 to 6 carbon atoms which may have at least one atom selected from the group consisting of a nitrogen atom, an oxygen atom and a silicon atom. R ⁶ and R ⁷ may be bonded to form a ring structure with the nitrogen atom, and R ⁶ and R ⁷ may be the same group bonded to the nitrogen by a double bond. ]

Examples of R ⁶ and R ^{7 in} formula (IIa) include a hydrocarbyl group having 1 to 6 carbon atoms, a substituted hydrocarbyl group having 1 to 6 carbon atoms, and a substituted silyl group.

As hydrocarbyl groups of R ⁶ and R ⁷ , methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, neopentyl group, isopentyl group And alkyl groups such as n-hexyl group; cycloalkyl groups such as cyclohexyl group; phenyl groups and the like.

The substituted hydrocarbyl group of R ⁶ and R ^{7 is} 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. 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; alkylene oxide group such as epoxy group, tetrahydrofuranyl group; alkylene oxide alkyl group such as glycidyl group, tetrahydrofurfuryl group, etc. Examples of the group having a group having a silicon atom as a substituent include a trialkylsilylalkyl group such as a trimethylsilylmethyl 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. 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.

Examples of the substituted silyl group of R ⁶ and R ⁷ include a trialkylsilyl group such as a trimethylsilyl group, a triethylsilyl group, and a t-butyldimethylsilyl group; a trialkoxysilyl group such as a trimethoxysilyl group.

The group to which R ⁶ and R ⁷ 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, an alkylene group such as a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group; an oxydialkylene group such as an oxydiethylene group and an oxydipropylene group; and —CH ₂ CH ₂ —NH—CH ₂ — And a nitrogen-containing group such as a group represented by —CH ₂ CH ₂ —N═CH—.

The group to which R ⁶ and R ⁷ 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 same group bonded to the nitrogen of R ⁶ and R ^{7 with} a double bond is the number of carbon atoms optionally having at least one atom selected from the group consisting of a nitrogen atom, an oxygen atom and a silicon atom 2 to 12 divalent groups. Examples thereof include an ethylidene group, 1-methylpropylidene group, 1,3-dimethylbutylidene group, 1-methylethylidene group, 4-N, N-dimethylaminobenzylidene group.

The hydrocarbyl group of R ⁶ and R ⁷ is preferably an alkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, and still more preferably a methyl group, an ethyl group, or an n-propyl group. , An n-butyl group, and more preferably a methyl group or an ethyl group. The substituted hydrocarbyl group for R ⁶ and R ⁷ is preferably an alkoxyalkyl group, an alkylene oxide group, or an alkylene oxide alkyl group. The substituted silyl group for R ⁶ and R ⁷ is preferably a trialkylsilyl group or a trialkoxysilyl group, more preferably a trialkylsilyl group, still more preferably a trimethylsilyl group or a triethylsilyl group. .

R ⁶ and R ⁷ are preferably a nitrogen-containing group, an alkyl group, an alkoxyalkyl group, an alkylene oxide group, an alkylene oxide alkyl group or a substituted silyl group to which R ⁶ and R ⁷ are bonded, and more preferably an alkyl group. A group, an alkylene oxide group, an alkylene oxide alkyl group, and a trialkylsilyl group.

Examples of the group represented by the formula (IIa) 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. In addition, di (alkylene oxide) amino groups such as di (epoxy) amino groups and di (tetrahydrofuranyl) amino groups; di (alkylene oxide alkyl) amino groups such as di (glycidyl) amino groups and di (tetrahydrofurfuryl) amino groups You can raise a group. Furthermore, an ethylideneamino group, 1-methylpropylideneamino group, 1,3-dimethylbutylideneamino group, 1-methylethylideneamino group, 4-N, N-dimethylaminobenzylideneamino group, and the like can also be mentioned.
In this specification, the di (alkylene oxide) amino group represents an amino group in which two hydrogen atoms bonded to a nitrogen atom are substituted with two alkylene oxide groups, and the di (alkylene oxide alkyl) amino group Represents an amino group in which two hydrogen atoms bonded to a nitrogen atom are substituted with two alkylene oxide alkyl groups.

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 (IIa) is preferably an acyclic amino group, more preferably a dialkyl, from the viewpoint of low fuel consumption, wet grip performance, wear resistance, long-term stability and availability of the compound. An amino group, a di (alkylene oxide) amino group, a di (alkylene oxide alkyl) amino group, and a di (trialkylsilyl) amino group.

As the compound represented by the formula (II), the formula (IIa) is a dialkylamino group, a di (alkoxyalkyl) amino group, a di (alkyleneoxide) amino group, a di (alkyleneoxidealkyl) amino group, a trialkylsilyl group. Examples thereof include compounds that are non-cyclic amino groups such as a group.

As the compound in which the formula (IIa) is a dialkylamino group,
[3- (dimethylamino) propyl] trimethoxysilane,
[3- (diethylamino) propyl] trimethoxysilane,
[3- (ethylmethylamino) propyl] trimethoxysilane,
[3- (dimethylamino) propyl] triethoxysilane,
[3- (diethylamino) propyl] triethoxysilane,
[3- (dialkylamino) propyl] trialkoxysilanes such as [3- (ethylmethylamino) propyl] triethoxysilane;

[3- (dimethylamino) propyl] methyldimethoxysilane,
[3- (diethylamino) propyl] methyldimethoxysilane,
[3- (ethylmethylamino) propyl] methyldimethoxysilane,
[3- (dimethylamino) propyl] ethyldimethoxysilane,
[3- (diethylamino) propyl] ethyldimethoxysilane,
[3- (ethylmethylamino) propyl] ethyldimethoxysilane,
[3- (dimethylamino) propyl] methyldiethoxysilane,
[3- (diethylamino) propyl] methyldiethoxysilane,
[3- (ethylmethylamino) propyl] methyldiethoxysilane,
[3- (dimethylamino) propyl] ethyldiethoxysilane,
[3- (diethylamino) propyl] ethyldiethoxysilane,
[3- (dialkylamino) propyl] alkyl dialkoxysilanes such as [3- (ethylmethylamino) propyl] ethyldiethoxysilane;

[3- (dimethylamino) propyl] dimethylmethoxysilane,
[3- (diethylamino) propyl] dimethylmethoxysilane,
[3- (dimethylamino) propyl] diethylmethoxysilane,
[3- (diethylamino) propyl] diethylmethoxysilane,
[3- (dimethylamino) propyl] dimethylethoxysilane,
[3- (diethylamino) propyl] dimethylethoxysilane,
[3- (dimethylamino) propyl] diethylethoxysilane,
[3- (Dialkylamino) propyl] dialkylalkoxysilanes such as [3- (diethylamino) propyl] diethylethoxysilane can be mentioned.

As the compound in which the formula (IIa) is a di (alkoxyalkyl) amino group,
{3- [di (methoxymethyl) amino] propyl} trimethoxysilane,
{3- [di (ethoxymethyl) amino] propyl} trimethoxysilane,
{3- [di (methoxyethyl) amino] propyl} trimethoxysilane,
{3- [di (ethoxyethyl) amino] propyl} trimethoxysilane,
{3- [di (methoxymethyl) amino] propyl} triethoxysilane,
{3- [di (ethoxymethyl) amino] propyl} triethoxysilane,
{3- [di (methoxyethyl) amino] propyl} triethoxysilane,
{3- [di (alkoxyalkyl) amino] propyl} trialkoxysilanes such as {3- [di (ethoxyethyl) amino] propyl} triethoxysilane;

{3- [di (methoxymethyl) amino] propyl} methyldimethoxysilane,
{3- [di (ethoxymethyl) amino] propyl} methyldimethoxysilane,
{3- [di (methoxyethyl) amino] propyl} methyldimethoxysilane,
{3- [di (ethoxyethyl) amino] propyl} methyldimethoxysilane,
{3- [di (methoxymethyl) amino] propyl} ethyldimethoxysilane,
{3- [di (ethoxymethyl) amino] propyl} ethyldimethoxysilane,
{3- [di (methoxyethyl) amino] propyl} ethyldimethoxysilane,
{3- [di (ethoxyethyl) amino] propyl} ethyldimethoxysilane,
{3- [di (methoxymethyl) amino] propyl} methyldiethoxysilane,
{3- [di (ethoxymethyl) amino] propyl} methyldiethoxysilane,
{3- [di (methoxyethyl) amino] propyl} methyldiethoxysilane,
{3- [di (ethoxyethyl) amino] propyl} methyldiethoxysilane,
{3- [di (methoxymethyl) amino] propyl} ethyldiethoxysilane,
{3- [di (ethoxymethyl) amino] propyl} ethyldiethoxysilane,
{3- [di (methoxyethyl) amino] propyl} ethyldiethoxysilane,
{3- [di (alkoxyalkyl) amino] propyl} alkyldialkoxysilanes such as {3- [di (ethoxyethyl) amino] propyl} ethyldiethoxysilane;

{3- [di (methoxymethyl) amino] propyl} dimethylmethoxysilane,
{3- [di (ethoxymethyl) amino] propyl} dimethylmethoxysilane,
{3- [di (methoxyethyl) amino] propyl} dimethylmethoxysilane,
{3- [di (ethoxyethyl) amino] propyl} dimethylmethoxysilane,
{3- [di (methoxymethyl) amino] propyl} diethylmethoxysilane,
{3- [di (ethoxymethyl) amino] propyl} diethylmethoxysilane,
{3- [di (methoxyethyl) amino] propyl} diethylmethoxysilane,
{3- [di (ethoxyethyl) amino] propyl} diethylmethoxysilane,
{3- [di (methoxymethyl) amino] propyl} dimethylethoxysilane,
{3- [di (ethoxymethyl) amino] propyl} dimethylethoxysilane,
{3- [di (methoxyethyl) amino] propyl} dimethylethoxysilane,
{3- [di (ethoxyethyl) amino] propyl} dimethylethoxysilane,
{3- [di (methoxymethyl) amino] propyl} diethylethoxysilane,
{3- [di (ethoxymethyl) amino] propyl} diethylethoxysilane,
{3- [di (methoxyethyl) amino] propyl} diethylethoxysilane,
Mention may be made of {3- [di (alkoxyalkyl) amino] propyl} dialkylalkoxysilanes such as {3- [di (ethoxyethyl) amino] propyl} diethylethoxysilane.

As the compound in which the formula (IIa) is a di (alkylene oxide) amino group,
{3- [di (epoxy) amino] propyl} trimethoxysilane,
{3- [di (epoxy) amino] propyl} triethoxysilane,
{3- [di (epoxy) amino] propyl} methyldimethoxysilane,
{3- [di (epoxy) amino] propyl} ethyldimethoxysilane,
{3- [di (epoxy) amino] propyl} methyldiethoxysilane,
{3- [di (epoxy) amino] propyl} ethyldiethoxysilane,
{3- [di (epoxy) amino] propyl} dimethylmethoxysilane,
{3- [di (epoxy) amino] propyl} diethylmethoxysilane,
{3- [di (epoxy) amino] propyl} dimethylethoxysilane,
Compounds in which the formula (IIa) is a di (epoxy) amino group such as {3- [di (epoxy) amino] propyl} diethylethoxysilane;

{3- [di (tetrahydrofuranyl) amino] propyl} trimethoxysilane,
{3- [di (tetrahydrofuranyl) amino] propyl} triethoxysilane,
{3- [di (tetrahydrofuranyl) amino] propyl} methyldimethoxysilane,
{3- [di (tetrahydrofuranyl) amino] propyl} ethyldimethoxysilane,
{3- [di (tetrahydrofuranyl) amino] propyl} methyldiethoxysilane,
{3- [di (tetrahydrofuranyl) amino] propyl} ethyldiethoxysilane,
{3- [di (tetrahydrofuranyl) amino] propyl} dimethylmethoxysilane,
{3- [di (tetrahydrofuranyl) amino] propyl} diethylmethoxysilane,
{3- [di (tetrahydrofuranyl) amino] propyl} dimethylethoxysilane,
Mention may be made of compounds in which the formula (IIa) is a di (tetrahydrofuranyl) amino group such as {3- [di (tetrahydrofuranyl) amino] propyl} diethylethoxysilane.

As the compound in which the formula (IIa) is a di (alkylene oxide alkyl) amino group,
{3- [di (glycidyl) amino] propyl} trimethoxysilane,
{3- [di (glycidyl) amino] propyl} triethoxysilane,
{3- [di (glycidyl) amino] propyl} methyldimethoxysilane,
{3- [di (glycidyl) amino] propyl} ethyldimethoxysilane,
{3- [di (glycidyl) amino] propyl} methyldiethoxysilane,
{3- [di (glycidyl) amino] propyl} ethyldiethoxysilane,
{3- [di (glycidyl) amino] propyl} dimethylmethoxysilane,
{3- [di (glycidyl) amino] propyl} diethylmethoxysilane,
{3- [di (glycidyl) amino] propyl} dimethylethoxysilane,
Compounds in which the formula (IIa) is a di (glycidyl) amino group such as {3- [di (glycidyl) amino] propyl} diethylethoxysilane;

{3- [di (tetrahydrofurfuryl) amino] propyl} trimethoxysilane,
{3- [di (tetrahydrofurfuryl) amino] propyl} triethoxysilane,
{3- [di (tetrahydrofurfuryl) amino] propyl} methyldimethoxysilane,
{3- [di (tetrahydrofurfuryl) amino] propyl} ethyldimethoxysilane,
{3- [di (tetrahydrofurfuryl) amino] propyl} methyldiethoxysilane,
{3- [di (tetrahydrofurfuryl) amino] propyl} ethyldiethoxysilane,
{3- [di (tetrahydrofurfuryl) amino] propyl} dimethylmethoxysilane,
{3- [di (tetrahydrofurfuryl) amino] propyl} diethylmethoxysilane,
{3- [di (tetrahydrofurfuryl) amino] propyl} dimethylethoxysilane,
Examples include compounds in which the formula (IIa) is a di (tetrahydrofurfuryl) amino group, such as {3- [di (tetrahydrofurfuryl) amino] propyl} diethylethoxysilane.

As a compound in which the formula (IIa) is a trialkylsilyl group,
{3- [di (trimethylsilyl) amino] propyl} trimethoxysilane,
{3- [di (t-butyldimethylsilyl) amino] propyl} trimethoxysilane,
{3- [di (trimethylsilyl) amino] propyl} triethoxysilane,
{3- [di (trialkylsilyl) amino] propyl} trialkoxysilanes such as {3- [di (t-butyldimethylsilyl) amino] propyl} triethoxysilane;

{3- [di (trimethylsilyl) amino] propyl} methyldimethoxysilane,
{3- [di (t-butyldimethylsilyl) amino] propyl} methyldimethoxysilane,
{3- [di (trimethylsilyl) amino] propyl} methyldiethoxysilane,
{3- [di (trialkylsilyl) amino] propyl} alkyldialkoxysilanes such as {3- [di (t-butyldimethylsilyl) amino] propyl} methyldiethoxysilane;

{3- [di (trimethylsilyl) amino] propyl} dimethylmethoxysilane,
{3- [di (t-butyldimethylsilyl) amino] propyl} dimethylmethoxysilane,
{3- [di (trimethylsilyl) amino] propyl} dimethylethoxysilane,
Mention may be made of {3- [di (trialkylsilyl) amino] propyl} dialkylalkoxysilanes such as {3- [di (t-butyldimethylsilyl) amino] propyl} dimethylethoxysilane.

Of these, [3- (dialkylamino) propyl] trialkoxysilane is preferred,
[3- (dimethylamino) propyl] trimethoxysilane,
[3- (diethylamino) propyl] trimethoxysilane,
[3- (dimethylamino) propyl] triethoxysilane,
[3- (Diethylamino) propyl] triethoxysilane is more preferred.

Moreover, as a compound represented by Formula (II), Formula (IIa) is 1-piperidino group, 1-hexamethyleneimino group, 1-imidazolyl group, 4,5-dihydro-1-imidazolyl group, 1- Examples thereof include compounds that are cyclic amino groups such as piperazinyl group and morpholino group.

As a compound in which the formula (IIa) is a 1-piperidino group,
3- (1-piperidino) propyltrimethoxysilane,
3- (1-piperidino) propyltriethoxysilane,
3- (1-piperidino) propylmethyldimethoxysilane,
3- (1-piperidino) propylethyldimethoxysilane,
3- (1-piperidino) propylmethyldiethoxysilane,
3- (1-piperidino) propylethyldiethoxysilane and the like can be mentioned.

As a compound in which the formula (IIa) is a 1-hexamethyleneimino group,
3- (1-hexamethyleneimino) propyltrimethoxysilane,
3- (1-hexamethyleneimino) propyltriethoxysilane,
3- (1-hexamethyleneimino) propylmethyldimethoxysilane,
3- (1-hexamethyleneimino) propylethyldimethoxysilane,
3- (1-hexamethyleneimino) propylmethyldiethoxysilane,
3- (1-hexamethyleneimino) propylethyldiethoxysilane and the like can be mentioned.

As a compound in which the formula (IIa) is a 1-imidazolyl group,
N- (3-trimethoxysilylpropyl) imidazole,
Examples thereof include N- (3-triethoxysilylpropyl) imidazole.

As a compound in which the formula (IIa) is a 4,5-dihydro-1-imidazolyl group,
N- (3-trimethoxysilylpropyl) -4,5-dihydroimidazole,
Examples thereof include N- (3-triethoxysilylpropyl) -4,5-dihydroimidazole.

As a compound in which the formula (IIa) is a 1-piperazinyl group,
3- (1-piperazinyl) propyltrimethoxysilane,
3- (1-piperazinyl) propyltriethoxysilane,
3- (1-piperazinyl) propylmethyldimethoxysilane,
3- (1-piperazinyl) propylethyldimethoxysilane,
3- (1-piperazinyl) propylmethyldiethoxysilane,
3- (1-piperazinyl) propylethyldiethoxysilane and the like can be mentioned.

As a compound in which the formula (IIa) is a morpholino group,
3-morpholinopropyltrimethoxysilane,
3-morpholinopropyltriethoxysilane,
3-morpholinopropylmethyldimethoxysilane,
3-morpholinopropylethyldimethoxysilane,
3-morpholinopropylmethyldiethoxysilane,
Examples thereof include 3-morpholinopropylethyldiethoxysilane.

In these, the compound whose formula (IIa) is 1-imidazolyl group, the compound whose formula (IIa) is 4,5-dihydro-1-imidazolyl group are preferable,
N- (3-trimethoxysilylpropyl) imidazole,
N- (3-triethoxysilylpropyl) imidazole,
N- (3-trimethoxysilylpropyl) -4,5-dihydroimidazole,
N- (3-triethoxysilylpropyl) -4,5-dihydroimidazole is more preferred.

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（ＩＩＩａ）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（ＩＩＩａ）で表される基である。］

［式中、Ｒ^８及びＲ^９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^８及びＲ^９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）で表される化合物とを反応させる工程。

［式中、ｎは１〜１０の整数を表し、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り、Ａは窒素原子を有する官能基を表す。］ 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): In a hydrocarbon solvent, a monomer containing a conjugated diene and a vinyl compound represented by the following formula (III) is polymerized with an alkali metal catalyst, 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 a vinyl compound represented by the formula (III).

[Wherein, X ⁴ , X ⁵ and X ⁶ each independently represent a group represented by the following formula (IIIa), 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 (IIIa). ]

Wherein, R ⁸ and R ⁹ each independently represent a hydrocarbyl group having 1 to 6 carbon atoms, a substituted hydrocarbyl group having 1-6 carbon atoms, a silyl group, or a substituted silyl group, R ⁸ and R ⁹ 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 the compound represented by the following formula (II).

[Wherein n represents an integer of 1 to 10, and R ³ , R ⁴ and R ⁵ each independently represents 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 ³ , R ⁴ and R ⁵ is a hydrocarbyloxy group, and A represents a functional group having a nitrogen atom. ]

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 formula (III) is polymerized, and a conjugated diene polymer having an alkali metal derived from the above-mentioned alkali metal catalyst at the end of the polymer chain. 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 (III) each independently represent a group represented by the formula (IIIa), 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 (IIIa).

R ⁸ and R ^{9 in} formula (IIIa) 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 ⁸ And R ⁹ may combine to form a ring structure together with the nitrogen atom.

Examples of the hydrocarbyl group having 1 to 6 carbon atoms of R ⁸ and R ⁹ 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 ⁸ and R ⁹ 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 for R ⁸ and R ⁹ include a trialkylsilyl group such as a trimethylsilyl group, a triethylsilyl group, and a t-butyldimethylsilyl group.

The group to which R ⁸ and R ⁹ 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, an alkylene group such as a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group; an oxydialkylene group such as an oxydiethylene group and an oxydipropylene group; and —CH ₂ CH ₂ —NH—CH ₂ — And a nitrogen-containing group such as a group represented by —CH ₂ CH ₂ —N═CH—.

The group to which R ⁸ and R ⁹ 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 ⁸ and R ⁹ 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 of R ⁸ and R ⁹ is preferably an alkoxyalkyl group, more preferably an alkoxyalkyl group having 1 to 4 carbon atoms. The substituted silyl group for R ⁸ and R ⁹ is preferably a trialkylsilyl group, and more preferably a trimethylsilyl group.

R ⁸ and R ⁹ are preferably an alkyl group, an alkoxyalkyl group, a substituted silyl group, or a nitrogen-containing group to which R ⁸ and R ⁹ 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 (IIIa) 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 (IIIa) 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 (III) 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 (III) is a group represented by the formula (IIIa). Preferably, two or more of X ⁴ , X ⁵ and X ⁶ are groups represented by formula (IIIa), more preferably two of X ⁴ , X ⁵ and X ⁶ are represented by formula (IIIa) It is a group represented.

As the vinyl compound represented by the formula (III) used in (Step A), one of X ^{4 to} X ⁶ is an acyclic amino group represented by the formula (IIIa), 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, (ethyliso (Propylamino) diethylvinylsilane, (di (n-propyl) amino) diethylvinylsilane, (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) dipropy Vinylsilane, (dimethylamino) dibutylvinylsilane, (ethylmethylamino) dibutylvinylsilane, (diethylamino) dibutylvinylsilane, (ethyl-n-propylamino) dibutylvinylsilane, (ethylisopropylamino) dibutylvinylsilane, (di (n-propyl) amino ) Dibutylvinylsilane, (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 (IIIa) 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) Methylvinylsilane, bis (dimethylamino) ethylvinylsilane, bis (ethylmethylamino) ethylvinylsilane, bis (diethylamino) ethylvinylsilane, bis (ethyl-n-propylamino) ethyl Vinylsilane, 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) ) Propyl vinyl silane, bis (di (n-propyl) amino) propyl vinyl silane, bis (diisopropylamino) propyl vinyl silane, bis (n-butyl-n-propylamino) Pyrvinylsilane, bis (di (n-butyl) amino) propylvinylsilane, bis (dimethylamino) butylvinylsilane, bis (ethylmethylamino) butylvinylsilane, bis (diethylamino) butylvinylsilane, bis (ethyl-n-propylamino) butyl Vinylsilane, bis (ethylisopropylamino) butylvinylsilane, bis (di (n-propyl) amino) butylvinylsilane, bis (diisopropylamino) butylvinylsilane, bis (n-butyl-n-propylamino) butylvinylsilane, bis (di ( and n-butyl) amino) butylvinylsilane.

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.

Bis (dialkylamino) alkoxyalkylvinylsilanes include bis (dimethylamino) methoxymethylvinylsilane, bis (dimethylamino) methoxyethylvinylsilane, bis (dimethylamino) ethoxymethylvinylsilane, bis (dimethylamino) ethoxyethylvinylsilane, and bis (diethylamino). ) Methoxymethylvinylsilane, bis (diethylamino) methoxyethylvinylsilane, bis (diethylamino) ethoxymethylvinylsilane, bis (diethylamino) ethoxyethylvinylsilane, and the like.

Examples of the compound in which three of X ^{4 to} X ⁶ are acyclic amino groups represented by the formula (IIIa) 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 (IIIa) 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 (III) in which two of X ⁴ , X ⁵ and X ⁶ are groups represented by the formula (IIIa), preferably two of X ⁴ , X ⁵ and X ⁶ are acyclic A vinyl compound which is an amino group, and from the viewpoint of low fuel consumption, wet grip performance and wear resistance, more preferably bis (dialkylamino) alkylvinylsilane, and still more preferably bis (dimethylamino) methylvinylsilane, Bis (diethylamino) methylvinylsilane, bis (di (n-propyl) amino) methylvinylsilane, and bis (di (n-butyl) amino) methylvinylsilane. 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 carried out by combining the conjugated diene and the vinyl compound represented by the formula (III) 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 compound represented by the formula (II) to be brought into contact with the polymer prepared in Step A is usually 0.1 to 3 mol per 1 mol of the alkali metal derived from the organic alkali metal catalyst. Preferably, it is 0.5-2 mol, More preferably, it is 0.7-1.5 mol.

In (Step B), the temperature at which the polymer prepared in Step A is brought into contact with the compound represented by formula (II) is usually 25 to 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 method for producing the conjugated diene polymer, a coupling agent may be added to the hydrocarbon solution of the conjugated diene polymer in the polymerization termination from the start of polymerization of the monomer using an alkali metal catalyst, if necessary. Good. Examples of the coupling agent include compounds represented by the following formula (IV).
R ¹⁰ _a ML _4-a (IV)
(Wherein R ¹⁰ 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 (IV), 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 can be further improved in a balanced wet grip performance and abrasion resistance.

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. Especially, it is preferable to use NR and / or BR, and it is more preferable to use both components of NR and BR from the point that low-fuel-consumption property, wet grip performance, and abrasion resistance can be improved with good balance.

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 is characterized by compounding silica as a reinforcing agent. The content of silica is 5 parts by mass or more, preferably 10 parts by mass or more, more preferably 40 parts by mass or more, and still more preferably 50 parts by mass with respect to 100 parts by mass of the rubber component. When the amount is less than 5 parts by mass, the effect of blending silica cannot be sufficiently obtained, and the wear resistance tends to decrease. Moreover, content of a silica 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, the workability tends to deteriorate. Silica may be used alone or in combination of two or more.

The content of silica in a total of 100% by mass of silica and carbon black is preferably 60% by mass or more, more preferably 85% by mass or more, preferably 98% by mass or less, more preferably 95% by mass or less. . If it is in the said range, low-fuel-consumption property, wet-grip performance, and abrasion resistance can be improved with a high dimension in a well-balanced manner.

The nitrogen adsorption specific surface area (N ₂ SA) of silica is preferably 40 m ² / g or more, more preferably 60 m ² / g or more. If it is less than 40 m < ² > / g, a reinforcement effect is small and there exists a tendency for abrasion resistance and fracture strength to fall. The nitrogen adsorption specific surface area (N ₂ SA) of silica is preferably 400 m ² / g or less, more preferably 360 m ² / g or less, and still more preferably 300 m ² / g or less. When it exceeds 400 m < ² > / g, it will become difficult to disperse | distribute a silica and there exists a tendency for low-fuel-consumption property and workability to deteriorate.
The nitrogen adsorption specific surface area of silica is a value measured by the BET method according to ASTM D3037-81.

It is preferable to mix | blend a silane coupling agent with the rubber composition of this invention with a silica. As the silane coupling agent, it is preferable to use bis (3-triethoxysilylpropyl) tetrasulfide or 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide from the viewpoint of reinforcing effect.

The content of the silane coupling agent is preferably 1 part by mass or more, more preferably 2 parts by mass or more with respect to 100 parts by mass of silica. If it is less than 1 part by mass, the viscosity of the unvulcanized rubber composition is high, and the processability tends to deteriorate. Further, the content of the silane coupling agent is preferably 20 parts by mass or less, more preferably 15 parts by mass or less. When it exceeds 20 parts by mass, there is a tendency that an effect commensurate with the increase in cost cannot be obtained.

The rubber composition of the present invention contains a liquid resin having a specific softening point. By using the liquid resin in combination with the conjugated diene polymer and silica, it is possible to synergistically improve fuel efficiency, wet grip performance, and wear resistance.

The liquid resin is usually a thermoplastic resin having a weight average molecular weight of several hundred to several thousand, and is a resin that can be given tackiness by blending with natural rubber or synthetic rubber. As the liquid resin, various natural resins and synthetic resins that are liquid can be used. For example, natural resins include coumarone indene resin, coumarone resin, indene resin, naphthene resin, phenol resin, terpene resin, terpene-phenol resin, rosin, rosin ester, hydrogenated rosin derivative, hydrogenated terpene resin and mixtures thereof. Etc. Synthetic resins include alkylphenol-formaldehyde resins, α-methylstyrene resins, C5 petroleum resins, C9 petroleum resins, aliphatic petroleum resins, xylene-formaldehyde resins, phenol-modified C9 petroleum resins, and carboxylic acid-modified C9 resins. Examples include petroleum resins and dicyclopentadiene-modified C9 petroleum resins. Among these, coumarone indene resin is preferable from the viewpoint of a balance between low fuel consumption, wet grip performance, and wear resistance. As the coumarone indene resin, a copolymer of coumarone, indene and styrene can be preferably used.

The softening point of the liquid resin is −20 ° C. or higher, preferably −5 ° C. or higher, more preferably 0 ° C. or higher. When the temperature is lower than -20 ° C, the viscosity of the liquid resin becomes too low, and the kneadability with the rubber component tends to deteriorate. The softening point of the liquid resin is 20 ° C. or lower, preferably 18 ° C. or lower, more preferably 17 ° C. or lower. When the temperature exceeds 20 ° C., the exothermic property of the liquid resin increases, and there is a tendency that low fuel consumption cannot be sufficiently improved.
In this specification, the softening point is a temperature at which a sphere descends when a softening point defined in JIS K6220: 2001 is measured by a ring and ball softening point measuring apparatus.

The content of the liquid resin is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and further preferably 2.5 parts by mass or more with respect to 100 parts by mass of the rubber component. If it is less than 1 part by mass, the effect of blending the liquid resin may not be sufficiently obtained. The content of the liquid resin is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and still more preferably 20 parts by mass or less. If it exceeds 40 parts by mass, the workability tends to deteriorate.

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. The content of carbon black is preferably 1 part by mass or more, more preferably 3 parts per 100 parts by mass of the rubber component from the viewpoint that fuel economy, wet grip performance and wear resistance can be improved in a high-dimensional and well-balanced manner. It is at least part by mass, preferably at most 30 parts by mass, more preferably at most 10 parts by mass.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is preferably 5 m ² / g or more, more preferably 50 m ² / g or more, preferably 200 m ² / g or less, more preferably 150 m ² / g or less. is there. 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 and wear resistance, and can achieve 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. In the following evaluation, Examples 1 to 5 and Comparative Examples 2 to 7 used Comparative Example 1 as a reference comparative example, and Example 6 used Comparative Example 8 as a reference comparative example.

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). tan δ
A strip-shaped test piece having a width of 1 mm or 2 mm and a length of 40 mm was punched out of the sheet-like vulcanized rubber composition and subjected to the test. Using a spectrometer manufactured by Ueshima Seisakusho, tan δ was measured at a dynamic strain amplitude of 1%, a frequency of 10 Hz, and a temperature of 50 ° C. The reciprocal value of tan δ was expressed as an index with the reference comparative example being 100. Larger values indicate lower rolling resistance and better fuel efficiency.

5. Rolling resistance Using a rolling resistance tester, measure the rolling resistance when the test tire was run at a rim (15 × 6JJ), internal pressure (230 kPa), load (3.43 kN), speed (80 km / h). Indicated as an index when the reference comparative example is 100. Larger values indicate lower rolling resistance and better fuel efficiency.

6). 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. Then, the wet grip performance index of the reference comparative example was set to 100, and the wet skid performance (wet grip performance) of each formulation was displayed as an index according to the following calculation formula. Larger values indicate better wet grip performance.
(Wet grip performance index) = (braking distance of reference comparative example) / (braking distance of each formulation) × 100

7. Using a wear resistance LAT tester (Laboratory Ablation and Skid Tester), the volume loss of each vulcanized rubber composition was measured under the conditions of a load of 50 N, a speed of 20 km / h, and a slip angle of 5 °. The numerical values (wear resistance index) in Tables 2 and 3 are relative values when the volume loss amount of the reference comparative example is 100. The larger the value, the better the wear resistance.

Production Example 1 (Synthesis of Polymer 1)
5. The inside of a stainless steel polymerization reactor having an internal volume of 20 liters was washed, dried, and replaced with dry nitrogen, hexane (specific gravity 0.68 g / cm ³ ) 10.2 kg, 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 reaction vessel. Next, 11.1 mmol of bis (diethylamino) methylvinylsilane and 13.1 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 reaction vessel. 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 11.1 mmol of 3-diethylaminopropyltriethoxysilane was added and stirred for 15 minutes. 20 ml of hexane solution containing 0.54 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 0.006 mmol / g polymer per polymer unit mass. there were.

Production Example 2 (Synthesis of Polymer 2)
The inside of the stainless steel polymerization reactor having an internal volume of 5 liters was washed, dried, and replaced with dry nitrogen, 2.55 kg of hexane (specific gravity 0.68 g / cm ³ ), 137 g of 1,3-butadiene, 43 g of styrene, tetrahydrofuran 1. 5 ml and 1.2 ml of ethylene glycol diethyl ether were charged into the polymerization reaction vessel. Next, 3.6 mmol of n-butyllithium was added as an n-hexane solution, and 1,3-butadiene and styrene were copolymerized for 2.5 hours. 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 reaction vessel. The supply amount of 1,3-butadiene was 205 g, and the supply amount of styrene was 65 g.
After the polymerization for 2.5 hours, 2.8 mmol of bis (diethylamino) methylvinylsilane as a cyclohexane solution was added into the polymerization reactor under a stirring speed of 130 rpm and a polymerization reactor internal temperature of 65 ° C. and stirred for 30 minutes. .
Next, 20 ml of a hexane solution containing 0.14 ml of methanol was put into the polymerization reactor, and the polymer solution was 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 0.006 mmol / g polymer per polymer unit mass. there were.

Production Example 3 (Synthesis of Polymer 3)
5. The inside of a stainless steel polymerization reactor having an internal volume of 20 liters was washed, dried, and replaced with dry nitrogen, hexane (specific gravity 0.68 g / cm ³ ) 10.2 kg, 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 reaction vessel. Next, 11.1 mmol of bis (diethylamino) methylvinylsilane and 13.1 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 reaction vessel. 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 0.54 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. 3 was recovered. 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 0.006 mmol / g polymer per polymer unit mass. there were.

Production Example 4 (Synthesis of Polymer 4)
5. The inside of a stainless steel polymerization reactor having an internal volume of 20 liters was washed, dried, and replaced with dry nitrogen, hexane (specific gravity 0.68 g / cm ³ ) 10.2 kg, 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 reaction vessel. Next, 13.1 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 reaction vessel. 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 11.1 mmol of 3-diethylaminopropyltriethoxysilane was added and stirred for 15 minutes. 20 ml of hexane solution containing 0.54 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, since the polymer 4 did not use the compound represented by Formula (III) at the time of a synthesis | combination, it did not contain the structural unit represented by Formula (I).

Production Example 5 (Synthesis of Polymer 5)
5. The inside of a stainless steel polymerization reactor having an internal volume of 20 liters was washed, dried, and replaced with dry nitrogen, hexane (specific gravity 0.68 g / cm ³ ) 10.2 kg, 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 reaction vessel. Next, 13.1 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 reaction vessel. 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 0.54 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 (III) at the time of a synthesis | combination, it did not contain the structural unit represented by Formula (I).

Production Example 6 (Synthesis of Polymer 6)
5. The inside of a stainless steel polymerization reactor having an internal volume of 20 liters was washed, dried, and replaced with dry nitrogen, hexane (specific gravity 0.68 g / cm ³ ) 10.2 kg, 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 reaction vessel. Next, 11.1 mmol of bis (diethylamino) methylvinylsilane and 13.1 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 reaction vessel. 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 11.1 mmol of 3-diethylaminopropyltriethoxysilane was added and stirred for 15 minutes. 20 ml of hexane solution containing 0.54 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 6. The evaluation results of the polymer 6 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 0.006 mmol / g polymer per polymer unit mass. there were.

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 1-6: Production Examples 1-6 above
Silica: Ultrasil VN3-G (N ₂ SA: 175 m ² / g) manufactured by Degussa
Silane coupling agent: Si69 (bis (3-triethoxysilylpropyl) tetrasulfide) 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)
Liquid resin 1: NOVARES C10 manufactured by Rutgers Chemicals (liquid coumarone indene resin, softening point: 5 to 15 ° C., viscosity: 10 Pa · s)
Liquid resin 2: Knit resin coumarone L-20 (manufactured by Nikkiso Chemical Co., Ltd.) (copolymer of coumarone, indene and styrene (liquid), softening point: less than 20 ° C., viscosity: 20 Pa · s)
Liquid resin 3: Maruka Clear H manufactured by Maruzen Petrochemical Co., Ltd. (polyisopentane (liquid), softening point: less than 20 ° C., viscosity: 10 Pa · s)
Solid resin: Pencel D160 manufactured by Arakawa Chemical Industries, Ltd. (solid rosin ester resin, softening point: 150 ° C. or higher)
Oil: X-140 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 flower No. 1 manufactured by Mitsui Kinzoku Mining Co., Ltd. Wax: Sunnock N manufactured by Ouchi Shinsei Chemical 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)
In accordance with the contents shown in Tables 2 and 3, materials other than sulfur and a vulcanization accelerator were kneaded for 5 minutes at 150 ° C. using a 1.7 L Banbury mixer manufactured by Kobe Steel, Ltd., and mixed. A kneaded paste was obtained. Next, sulfur and a vulcanization accelerator were added to the obtained kneaded product, and kneaded for 5 minutes under the condition of 80 ° C. using an open roll to obtain an unvulcanized rubber composition. The obtained unvulcanized rubber composition was press vulcanized with a 0.5 mm thick mold at 170 ° C. for 20 minutes to obtain a vulcanized rubber composition.
Further, the obtained unvulcanized rubber composition was 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 170 ° C. for 12 minutes, A test tire (size: 195 / 65R15) was produced.

The obtained vulcanized rubber composition and test tire were used for evaluation by the above test method. The test results are shown in Tables 2 and 3.

As shown in Tables 2 and 3, a polymer having a structural unit based on a conjugated diene and a structural unit represented by the above formula (I), and having a terminal modified with the compound represented by the above formula (II) Examples in which (polymers 1 and 6), silica, and a liquid resin having a specific softening point (liquid resins 1 to 3) are used in combination have low fuel consumption, wet grip performance and resistance to resistance. Abrasion was improved in a well-balanced manner.

Claims (11)

Containing a rubber component, silica, and a liquid resin having a softening point of -20 to 20 ° C,
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 at least one end of the polymer is modified by the compound represented by the following formula (II) The conjugated diene polymer content is 5% by mass or more,
The rubber composition, wherein a content of the silica is 5 to 150 parts by mass with respect to 100 parts by mass of the rubber component.

[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. ]

[Wherein n represents an integer of 1 to 10, and R ³ , R ⁴ and R ⁵ each independently represents 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 ³ , R ⁴ and R ⁵ is a hydrocarbyloxy group, and A represents a functional group having a 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 any one of claims 1 to 3, wherein A in the formula (II) is a group represented by the following formula (IIa).

[Wherein R ⁶ and R ⁷ each independently have 1 to 6 carbon atoms which may have at least one atom selected from the group consisting of a nitrogen atom, an oxygen atom and a silicon atom. R ⁶ and R ⁷ may be bonded to form a ring structure with the nitrogen atom, and R ⁶ and R ⁷ may be the same group bonded to the nitrogen by a double bond. ] The vinyl bond amount of the conjugated diene polymer is 10 mol% or more and 80 mol% or less, where the content of the constituent unit based on the conjugated diene is 100 mol%. The rubber composition as described. Natural rubber and / or butadiene rubber are contained, The rubber composition in any one of Claims 1-5 characterized by the above-mentioned. The rubber composition according to claim 1, wherein the silica has a nitrogen adsorption specific surface area of 40 to 400 m ² / g. The rubber composition according to any one of claims 1 to 7, wherein the content of the liquid resin is 1 to 40 parts by mass with respect to 100 parts by mass of the rubber component. The rubber composition according to any one of claims 1 to 8, wherein the liquid resin is a coumarone indene resin. The rubber composition according to any one of claims 1 to 9, 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 1-10.