JP2012241165A - Rubber composition and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition with which low fuel consumption property, wet grip performance, wear resistance, and kneading workability are improved in a well-balanced manner, and a pneumatic tire which uses the rubber composition.SOLUTION: In the rubber composition, a rubber component satisfies requirements that the Mooney viscosity is 40-49, molecular weight distribution is 3.0-3.9, and the velocity-dependent index of the Mooney viscosity is 2.3-3.0, wherein the content of a high-cis polybutadiene having a cis content of 95 mass% or more is 10-70 mass%, and the content of a conjugated diene polymer that includes a structural unit of a conjugated diene and a structural unit of vinylsilane represented by formula (I), and has at least one end thereof modified by a (meth)acrylate or a (meth)acrylic amide with an oxygen- or nitrogen-containing functional group on a terminal thereof, is 30-90 mass%, and contains 5-150 pts.mass of silica per 100 pts.mass of the rubber component. [Wherein, each of X, X, and Xis mutually independent, and one of them is a predetermined amino group or a hydroxy group, and others are each a substituted (or unsubstituted) alkyl group].

Description

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

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

As a method for improving fuel 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.

Further, polybutadiene rubber is generally used for improving the wear resistance, and the wear resistance is improved by increasing the molecular weight of the polybutadiene rubber. However, there is a problem that kneading processability is deteriorated by increasing the molecular weight of the polybutadiene rubber. Thus, there is a need for a method for improving fuel economy, wet grip performance, wear resistance, and kneading workability in a well-balanced manner.

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, wear resistance, and kneadability 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は、水素原子、炭素原子数が１〜６のヒドロカルビル基又は炭素原子数が１〜６の置換ヒドロカルビル基を表し、Ａ^１は、酸素原子又は−ＮＲ^４−基（Ｒ^４は、水素原子又は炭素原子数が１〜１０のヒドロカルビル基を表す。）を表し、Ａ^２は、窒素原子及び／又は酸素原子を有する官能基を表す。］ The present invention contains a rubber component and silica, and among 100% by mass of the rubber component, (A) Mooney viscosity (ML): 40 to 49, (B) molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn) : 3.0-3.9 and (C) Mooney viscosity rate dependency index (n value of formula (1)): satisfying the requirement of 2.3-3.0, and cis content is 95% by mass or more The content of the high cis polybutadiene is from 10 to 70% by mass, has a structural unit based on a conjugated diene and a structural unit represented by the following formula (I), and is represented by the compound represented by the following formula (II): The content of the conjugated diene polymer obtained by modifying at least one end of the polymer is 30 to 90% by mass, and the content of the silica with respect to 100 parts by mass of the rubber component is 5 to 150 parts by mass. It relates to a rubber composition.
log (ML) = log (K) + n ⁻¹ × log (RS) Formula (1)
(However, RS represents the number of rotations per minute of the rotor, K represents an arbitrary number, and ML represents Mooney viscosity.)

[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, R ³ represents a hydrogen atom, a hydrocarbyl group having 1 to 6 carbon atoms, or a substituted hydrocarbyl group having 1 to 6 carbon atoms, and A ¹ represents , An oxygen atom or a —NR ⁴ — group (R ⁴ represents a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms), and A ² represents a functional group having a nitrogen atom and / or an oxygen atom. Represent. ]

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^５及びＲ^６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^５及びＲ^６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^５及びＲ^６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 ^{2 in the} formula (II) is preferably a group or a hydroxyl group represented by the following formula (III).

[Wherein, R ⁵ and R ⁶ 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 ⁵ and R ⁶ may be bonded to form a ring structure together with the nitrogen atom, and R ⁵ and R ⁶ may be the same group bonded to 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%.

It is preferable that the ratio (Tcp / ML) of 5 mass% toluene solution viscosity (Tcp) and Mooney viscosity (ML) of the high cis polybutadiene is 2.5 to 3.5.

It is preferable that Mw of the high cis polybutadiene is 500,000 to 700,000 and Mn is 120,000 to 250,000.

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

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, a rubber composition containing a specific amount of a specific high-cis polybutadiene, a specific amount of a specific conjugated diene polymer, and a specific amount of silica is combined. Further, it is possible to provide a pneumatic tire with improved wear resistance and kneading workability in a well-balanced manner.

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

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

［式中、ｎは、１〜１０の整数を表し、Ｒ^３は、水素原子、炭素原子数が１〜６のヒドロカルビル基又は炭素原子数が１〜６の置換ヒドロカルビル基を表し、Ａ^１は、酸素原子又は−ＮＲ^４−基（Ｒ^４は、水素原子又は炭素原子数が１〜１０のヒドロカルビル基を表す。）を表し、Ａ^２は、窒素原子及び／又は酸素原子を有する官能基を表す。］ The rubber composition of the present invention comprises (A) Mooney viscosity (ML): 40 to 49, (B) molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn): 3.0 to 3.9, and (C) Mooney. Viscosity rate-dependent index (n value in formula (1)): satisfying the requirements of 2.3 to 3.0 and having a cis content of 95% by mass or more, a high cis polybutadiene, a structural unit based on conjugated diene and A rubber component having a structural unit represented by the formula (I), each containing a specific amount of a conjugated diene polymer obtained by modifying at least one end of the polymer with a compound represented by the following formula (II): A specific amount of silica.
log (ML) = log (K) + n ⁻¹ × log (RS) Formula (1)
(However, RS represents the number of rotations per minute of the rotor, K represents an arbitrary number, and ML represents Mooney viscosity.)

[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, R ³ represents a hydrogen atom, a hydrocarbyl group having 1 to 6 carbon atoms, or a substituted hydrocarbyl group having 1 to 6 carbon atoms, and A ¹ represents , An oxygen atom or a —NR ⁴ — group (R ⁴ represents a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms), and A ² represents a functional group having a nitrogen atom and / or an oxygen atom. Represent. ]

The conjugated diene polymer has a modifying group at the main chain and terminal and has strong interaction with silica, so it can disperse silica well, improving fuel economy, wet grip performance, and wear resistance. On the other hand, there are cases where the kneadability is inferior compared to rubbers having no modifying group.
In addition, the high-cis polybutadiene blends well with silica from the early stage after the start of kneading, so that good kneadability can be obtained and fuel efficiency and wear resistance can be improved, but wet grip performance is improved. The effect may not be obtained. For example, in a rubber composition containing silica, when the high-cis polybutadiene is used in combination with unmodified styrene butadiene rubber, styrene butadiene rubber modified only at the end, styrene butadiene rubber modified only in the main chain, etc. The wet grip performance improvement effect cannot be obtained sufficiently.
On the other hand, in the present invention, in the rubber composition containing silica, by using the conjugated diene polymer together with the high-cis polybutadiene, low fuel consumption, wet grip performance, wear resistance, kneadability (particularly, Kneading workability) can be synergistically improved, and excellent fuel economy, wet grip performance, wear resistance, and kneading workability can be obtained in a balanced manner.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

［式中、ｎは、１〜１０の整数を表し、Ｒ^３は、水素原子、炭素原子数が１〜６のヒドロカルビル基又は炭素原子数が１〜６の置換ヒドロカルビル基を表し、Ａ^１は、酸素原子又は−ＮＲ^４−基（Ｒ^４は、水素原子又は炭素原子数が１〜１０のヒドロカルビル基を表す。）を表し、Ａ^２は、窒素原子及び／又は酸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, R ³ represents a hydrogen atom, a hydrocarbyl group having 1 to 6 carbon atoms, or a substituted hydrocarbyl group having 1 to 6 carbon atoms, and A ¹ represents , An oxygen atom or a —NR ⁴ — group (R ⁴ represents a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms), and A ² represents a functional group having a nitrogen atom and / or an oxygen atom. Represent. ]

n represents an integer of 1 to 10. From the viewpoint of improving the fuel efficiency, wet grip performance, wear resistance, and kneading workability in a well-balanced manner, it is preferably 2 or more, and more preferably 4 or less from the viewpoint of improving economy during production. More preferably, it is 3.

R ^{3 in} formula (II) represents a hydrogen atom, a hydrocarbyl group having 1 to 6 carbon atoms, or a substituted hydrocarbyl group having 1 to 6 carbon atoms.

Examples of the hydrocarbyl group of R ³ include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, and t-butyl group.

Examples of the substituted hydrocarbyl group of R ³ include a substituted hydrocarbyl group having as a substituent at least one group selected from the group consisting of a group having a nitrogen atom, a group having an oxygen atom, and a group having a silicon atom. it can. Examples of the group having a group having a nitrogen atom as a substituent include dialkylaminoalkyl groups such as a dimethylaminoethyl group and a diethylaminoethyl group. Examples of the group having a group having an oxygen atom as a substituent include methoxymethyl An alkoxyalkyl group such as a methoxyethyl group, an ethoxymethyl group, and an ethoxyethyl group, and a group having a silicon atom group as a substituent includes a trialkylsilylalkyl group such as a trimethylsilylmethyl group; Examples thereof include a trialkylsilyloxyalkyl group such as a butyldimethylsilyloxymethyl group; a trialkoxysilylalkyl group such as a trimethoxysilylpropyl group.

The hydrocarbyl group for R ³ is preferably an alkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, still more preferably a methyl group or an ethyl group, still more preferably It is a methyl group. The substituted hydrocarbyl group for R ³ is preferably an alkoxyalkyl group, more preferably an alkoxyalkyl group having 1 to 4 carbon atoms, still more preferably a methoxymethyl group or an ethoxyethyl group. More preferably a methoxymethyl group.

R ³ is preferably a hydrogen atom, an alkyl group, or an alkoxyalkyl group, more preferably a hydrogen atom, an alkyl group, or an alkoxyalkyl group from the viewpoint of improving fuel economy, wet grip performance, wear resistance, kneading workability in a balanced manner and economy. An atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxyalkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group, or a methoxymethyl group, still more preferably a hydrogen atom, It is a methyl group.

A ^{1 in the} formula (II) represents an oxygen atom or a —NR ⁴ — group, and R ⁴ represents a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms.

As the hydrocarbyl group of R ⁴ , alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, t-butyl group; phenyl group, methylphenyl group, ethylphenyl group An aryl group such as a naphthyl group; and an aralkyl group such as a benzyl group.

The hydrocarbyl group for R ⁴ 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.

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

A ^{2 in the} formula (II) represents a functional group having a nitrogen atom and / or an oxygen atom.
Examples of the functional group having a nitrogen atom include an amino group, isocyano group, cyano group, pyridyl group, piperidyl group, piperazinyl group, morpholino group and the like.

Examples of functional groups having an oxygen atom include alkoxy groups such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, and t-butoxy; methoxymethyl, methoxyethyl And alkoxyalkyl groups such as ethoxymethyl group and ethoxyethyl group; alkoxyaryl groups such as methoxyphenyl group and ethoxyphenyl group; and alkylene oxide groups such as epoxy group and tetrahydrofuranyl group. Moreover, trialkyl silyloxy groups, such as a trimethyl silyloxy group, a triethyl silyloxy group, and t-butyldimethyl silyloxy group, can be mentioned. Moreover, a hydroxyl group can be mention | raise | lifted.

［式中、Ｒ^５及びＲ^６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^５及びＲ^６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^５及びＲ^６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 ² is preferably a group or a hydroxyl group represented by the following formula (III), more preferably a group represented by the following formula (III).

[Wherein, R ⁵ and R ⁶ 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 ⁵ and R ⁶ may be bonded to form a ring structure together with the nitrogen atom, and R ⁵ and R ⁶ may be the same group bonded to nitrogen by a double bond. ]

Examples of R ⁵ and R ^{6 in} formula (III) 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.

Examples of the hydrocarbyl group of R ⁵ and R ⁶ include 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 ⁵ and R ^{6 includes} a substituted hydrocarbyl group having at least one group selected from the group consisting of a group having a nitrogen atom, a group having an oxygen atom and a group having a silicon atom as a substituent. I can give you. Examples of the group having a group having a nitrogen atom as a substituent include dialkylaminoalkyl groups such as a dimethylaminoethyl group and a diethylaminoethyl group. Examples of the group having a group having an oxygen atom as a substituent include methoxymethyl Group, alkoxyalkyl group such as methoxyethyl group, ethoxymethyl group, ethoxyethyl group; 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 for R ⁵ and R ⁶ include trialkylsilyl groups such as trimethylsilyl group, triethylsilyl group and t-butyldimethylsilyl group; trialkoxysilyl groups such as trimethoxysilyl group.

The group to which R ⁵ and R ⁶ are bonded is a divalent divalent having 2 to 12 carbon atoms that may have at least one atom selected from the group consisting of a nitrogen atom, an oxygen atom and a silicon atom. Group. For example, trimethylene group, tetramethylene group, pentamethylene group, alkylene groups such as a hexamethylene group; oxy oxydialkylene groups such as dipropylene _{group; -CH 2 CH 2 -NH-CH} 2 - is represented by And a nitrogen-containing group such as a group represented by —CH ₂ CH ₂ —N═CH—.

The group to which R ⁵ and R ⁶ 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 ⁵ and R ^{6 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 ⁵ and R ⁶ 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 ⁵ and R ⁶ is preferably an alkoxyalkyl group, an alkylene oxide group, or an alkylene oxide alkyl group. The substituted silyl group for R ⁵ and R ⁶ 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 ⁵ and R ⁶ 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 ⁵ and R ⁶ 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 (III) 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 (III) is preferably an acyclic amino group, more preferably a dialkyl, from the viewpoint of fuel economy, 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.

Examples of the compound represented by the formula (II) include acrylamide compounds and methacrylamide compounds as compounds in which A ¹ is a secondary amino group.

As an acrylamide compound in which A ² is a group containing a nitrogen atom,
N- (2-dimethylaminoethyl) acrylamide,
N- (2-diethylaminoethyl) acrylamide,
N- (3-dimethylaminopropyl) acrylamide,
N- (3-diethylaminopropyl) acrylamide,
N- (4-dimethylaminobutyl) acrylamide,
N- (4-diethylaminobutyl) acrylamide,
N- (3-morpholinopropyl) acrylamide,
And N- (3-cyanopropyl) acrylamide.

As a methacrylamide compound in which A ² is a nitrogen atom-containing group,
N- (2-dimethylaminoethyl) methacrylamide,
N- (2-diethylaminoethyl) methacrylamide,
N- (3-dimethylaminopropyl) methacrylamide,
N- (3-diethylaminopropyl) methacrylamide,
N- (4-dimethylaminobutyl) methacrylamide,
N- (4-diethylaminobutyl) methacrylamide,
N- (3-morpholinopropyl) methacrylamide,
N- (3-cyanopropyl) methacrylamide and the like.

As an acrylamide compound in which A ² is an oxygen atom-containing group,
N- (3-methoxypropyl) acrylamide,
N- (3-ethoxypropyl) acrylamide,
N- (propoxymethyl) acrylamide,
N- (butoxymethyl) acrylamide,
N-glycidyl acrylamide,
Examples thereof include N-tetrahydrofurfuryl acrylamide.

As a methacrylamide compound in which A ² is an oxygen atom-containing group,
N- (3-methoxypropyl) methacrylamide,
N- (3-ethoxypropyl) methacrylamide,
N- (propoxymethyl) methacrylamide,
N- (butoxymethyl) methacrylamide,
N-glycidyl methacrylamide,
Examples thereof include N-tetrahydrofurfuryl methacrylamide.

As an acrylamide compound in which A ² is a group containing a nitrogen atom and an oxygen atom,
N- (3-di (glycidyl) aminopropyl) acrylamide,
N- (3-di (tetrahyhydrofurfuryl) aminopropyl) acrylamide and the like.

As the methacrylamide compound in which A ² is a group containing a nitrogen atom and an oxygen atom,
N- (3-di (glycidyl) aminopropyl) methacrylamide,
N- (3-di (tetrahyhydrofurfuryl) aminopropyl) methacrylamide and the like.

Examples of the compound represented by the formula (II) include acrylate compounds and methacrylate compounds as compounds in which A ¹ is an oxygen atom.

As an acrylate compound in which A ² is a nitrogen atom-containing group,
2-dimethylaminoethyl acrylate,
2-diethylaminoethyl acrylate,
3-dimethylaminopropyl acrylate,
3-diethylaminopropyl acrylate,
4-dimethylaminobutyl acrylate,
Examples include 4-diethylaminobutyl acrylate.

As a methacrylate compound in which A ² is a nitrogen atom-containing group,
2-dimethylaminoethyl methacrylate,
2-diethylaminoethyl methacrylate,
3-dimethylaminopropyl methacrylate,
3-diethylaminopropyl methacrylate,
4-dimethylaminobutyl methacrylate,
Examples include 4-diethylaminobutyl methacrylate.

As an acrylate compound in which A ² is an oxygen atom-containing group,
2-ethoxyethyl acrylate,
2-propoxyethyl acrylate,
2-butoxyethyl acrylate,
3-methoxypropyl acrylate,
3-ethoxypropyl acrylate,
Glycidyl acrylate,
And tetrahydrofurfuryl acrylate.

As a methacrylate compound in which A ² is an oxygen atom-containing group,
2-ethoxyethyl methacrylate,
2-propoxyethyl methacrylate,
2-butoxyethyl methacrylate,
3-methoxypropyl methacrylate,
3-ethoxypropyl methacrylate,
Glycidyl methacrylate,
And tetrahydrofurfuryl methacrylate.

As the acrylate compound in which A ² is a group containing a nitrogen atom and an oxygen atom,
3-di (glycidyl) aminopropyl acrylate,
Examples include 3-di (tetrahydrofurfuryl) aminopropyl acrylate.

Examples of the methacrylate compound in which A ² is a group containing a nitrogen atom and an oxygen atom include 3-di (glycidyl) aminopropyl methacrylate and 3-di (tetrahydrofurfuryl) aminopropyl methacrylate.

As a compound represented by the formula (II), from the viewpoint of improving fuel economy, wet grip performance, wear resistance, kneading workability in a balanced manner,
Preferably, it is a compound in which A ² is a group represented by the formula (III), more preferably a compound in which A ¹ is an amino group and A ² is a group represented by the formula (III). More preferably, A ¹ is a secondary amino group (—NH—), and A ² is a compound represented by the formula (III).

As the compound wherein A ¹ is a secondary amino group and A ² is a group represented by the formula (III),
Preferably,
N- (3-dialkylaminopropyl) acrylamide, N- (3-dialkylaminopropyl) methacrylamide,
More preferably,
N- (3-dimethylaminopropyl) acrylamide,
N- (3-diethylaminopropyl) acrylamide,
N- (3-dimethylaminopropyl) methacrylamide,
N- (3-diethylaminopropyl) methacrylamide.

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（ＩＶａ）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（ＩＶａ）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は、水素原子、炭素原子数が１〜６のヒドロカルビル基又は炭素原子数が１〜６の置換ヒドロカルビル基を表し、Ａ^１は、酸素原子又は−ＮＲ^４−基（Ｒ^４は、水素原子又は炭素原子数が１〜１０のヒドロカルビル基を表す。）を表し、Ａ^２は、窒素原子及び／又は酸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 (IV) 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 (IV).

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

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, R ³ represents a hydrogen atom, a hydrocarbyl group having 1 to 6 carbon atoms, or a substituted hydrocarbyl group having 1 to 6 carbon atoms, and A ¹ represents , An oxygen atom or a —NR ⁴ — group (R ⁴ represents a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms), and A ² represents a functional group having a nitrogen atom and / or an oxygen atom. Represent. ]

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

X ⁴ , X ⁵ and X ⁶ in the formula (IV) each independently represent a group represented by the formula (IVa), 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 (IVa).

R ⁸ and R ^{9 in} formula (IVa) 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 mention | raise | lift. 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, trimethylene group, tetramethylene group, pentamethylene group, alkylene groups such as a hexamethylene group; oxy oxydialkylene groups such as dipropylene _{group; -CH 2 CH 2 -NH-CH} 2 - is represented by And a nitrogen-containing group such as a group represented by —CH ₂ CH ₂ —N═CH—.

The group to which R 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 (IVa) 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 (IVa) 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 (IV) 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. Further, examples of the substituted hydrocarbyl group of X ^{4 to} X ⁶ 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 (IV) is a group represented by the formula (IVa). Preferably, two or more of X ⁴ , X ⁵ and X ⁶ are groups represented by formula (IVa), more preferably two of X ⁴ , X ⁵ and X ⁶ are represented by formula (IVa) It is a group represented.

As the vinyl compound represented by formula (IV) used in (Step A), one of X ^{4 to} X ⁶ is an acyclic amino group represented by formula (IVa), and two are hydrocarbyl groups or substituted hydrocarbyls. Examples of the group-containing compound include (dialkylamino) dialkylvinylsilane, {di (trialkylsilyl) amino} dialkylvinylsilane, (dialkylamino) dialkoxyalkylvinylsilane, and the like.

(Dialkylamino) dialkylvinylsilane includes (dimethylamino) dimethylvinylsilane, (ethylmethylamino) dimethylvinylsilane, (diethylamino) dimethylvinylsilane, (ethyl-n-propylamino) dimethylvinylsilane, (ethylisopropylamino) dimethylvinylsilane, ( Di (n-propyl) amino) dimethylvinylsilane, (diisopropylamino) dimethylvinylsilane, (n-butyl-n-propylamino) dimethylvinylsilane, (di (n-butyl) amino) dimethylvinylsilane,
(Dimethylamino) diethylvinylsilane, (ethylmethylamino) diethylvinylsilane, (diethylamino) diethylvinylsilane, (ethyl-n-propylamino) diethylvinylsilane, (ethylisopropylamino) diethylvinylsilane, (di (n-propyl) amino) diethyl Vinylsilane, (diisopropylamino) diethylvinylsilane, (n-butyl-n-propylamino) diethylvinylsilane, (di (n-butyl) amino) diethylvinylsilane,
(Dimethylamino) dipropylvinylsilane, (ethylmethylamino) dipropylvinylsilane, (diethylamino) dipropylvinylsilane, (ethyl-n-propylamino) dipropylvinylsilane, (ethylisopropylamino) dipropylvinylsilane, (di (n- Propyl) amino) dipropylvinylsilane, (diisopropylamino) dipropylvinylsilane, (n-butyl-n-propylamino) dipropylvinylsilane, (di (n-butyl) amino) dipropylvinylsilane,
(Dimethylamino) dibutylvinylsilane, (ethylmethylamino) dibutylvinylsilane, (diethylamino) dibutylvinylsilane, (ethyl-n-propylamino) dibutylvinylsilane, (ethylisopropylamino) dibutylvinylsilane, (di (n-propyl) amino) dibutyl Examples include vinylsilane, (diisopropylamino) dibutylvinylsilane, (n-butyl-n-propylamino) dibutylvinylsilane, (di (n-butyl) amino) dibutylvinylsilane, and the like.

As {di (trialkylsilyl) amino} dialkylvinylsilane, {di (trimethylsilyl) amino} dimethylvinylsilane, {di (t-butyldimethylsilyl) amino} dimethylvinylsilane, {di (trimethylsilyl) amino} diethylvinylsilane, {di (T-butyldimethylsilyl) amino} diethylvinylsilane and the like.

(Dialkylamino) dialkoxyalkylvinylsilane includes (dimethylamino) dimethoxymethylvinylsilane, (dimethylamino) dimethoxyethylvinylsilane, (dimethylamino) diethoxymethylvinylsilane, (dimethylamino) diethoxyethylvinylsilane, (diethylamino) dimethoxymethyl Examples thereof include vinylsilane, (diethylamino) dimethoxyethylvinylsilane, (diethylamino) diethoxymethylvinylsilane, (diethylamino) diethoxyethylvinylsilane, and the like.

Compounds in which two of X ^{4 to} X ⁶ are acyclic amino groups represented by the formula (IVa) and one is a hydrocarbyl group or a substituted hydrocarbyl group include bis (dialkylamino) alkylvinylsilane, bis {di (trialkyl Silyl) amino} alkylvinylsilane, bis (dialkylamino) alkoxyalkylvinylsilane, and the like.

Examples of bis (dialkylamino) alkylvinylsilane include bis (dimethylamino) methylvinylsilane, bis (ethylmethylamino) methylvinylsilane, bis (diethylamino) methylvinylsilane, bis (ethyl-n-propylamino) methylvinylsilane, and bis (ethylisopropyl). Amino) methylvinylsilane, bis (di (n-propyl) amino) methylvinylsilane, bis (diisopropylamino) methylvinylsilane, bis (n-butyl-n-propylamino) methylvinylsilane, bis (di (n-butyl) amino) Methyl vinyl silane,
Bis (dimethylamino) ethylvinylsilane, bis (ethylmethylamino) ethylvinylsilane, bis (diethylamino) ethylvinylsilane, bis (ethyl-n-propylamino) ethylvinylsilane, bis (ethylisopropylamino) ethylvinylsilane, bis (di (n -Propyl) amino) ethylvinylsilane, bis (diisopropylamino) ethylvinylsilane, bis (n-butyl-n-propylamino) ethylvinylsilane, bis (di (n-butyl) amino) ethylvinylsilane,
Bis (dimethylamino) propylvinylsilane, bis (ethylmethylamino) propylvinylsilane, bis (diethylamino) propylvinylsilane, bis (ethyl-n-propylamino) propylvinylsilane, bis (ethylisopropylamino) propylvinylsilane, bis (di (n -Propyl) amino) propylvinylsilane, bis (diisopropylamino) propylvinylsilane, bis (n-butyl-n-propylamino) propylvinylsilane, bis (di (n-butyl) amino) propylvinylsilane,
Bis (dimethylamino) butylvinylsilane, bis (ethylmethylamino) butylvinylsilane, bis (diethylamino) butylvinylsilane, bis (ethyl-n-propylamino) butylvinylsilane, bis (ethylisopropylamino) butylvinylsilane, bis (di (n -Propyl) amino) butylvinylsilane, bis (diisopropylamino) butylvinylsilane, bis (n-butyl-n-propylamino) butylvinylsilane, bis (di (n-butyl) amino) butylvinylsilane, and the like.

As bis {di (trialkylsilyl) amino} alkylvinylsilane, bis {di (trimethylsilyl) amino} methylvinylsilane, bis {di (t-butyldimethylsilyl) amino} methylvinylsilane, bis {di (trimethylsilyl) amino} ethyl Examples include vinyl silane and bis {di (t-butyldimethylsilyl) amino} ethyl vinyl silane.

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

In (Step A), polymerization may be performed by combining the conjugated diene and the vinyl compound represented by the formula (IV) 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. An example of the coupling agent is a compound represented by the following formula (V).
R ¹⁰ _a ML _4-a (V)
(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 (V), silicon tetrachloride, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, tin tetrachloride, methyltrichlorotin, dimethyldichlorotin, trimethylchlorotin, tetramethoxysilane, methyl Examples include trimethoxysilane, dimethoxydimethylsilane, methyltriethoxysilane, ethyltrimethoxysilane, dimethoxydiethylsilane, diethoxydimethylsilane, tetraethoxysilane, ethyltriethoxysilane, and diethoxydiethylsilane.

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

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

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

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.

The content of the conjugated diene polymer in 100% by mass of the rubber component is 30% by mass or more, preferably 40% by mass or more, and more preferably 50% by mass or more. When the content of the conjugated diene polymer is less than 30% by mass, sufficient wet grip performance cannot be obtained. The content of the conjugated diene polymer is 90% by mass or less, preferably 80% by mass or less. When the content of the conjugated diene polymer exceeds 90% by mass, sufficient wear resistance and kneading workability cannot be obtained.

In the present invention, the high cis polybutadiene (high cis polybutadiene rubber) is used as the rubber component together with the conjugated diene polymer.

The Mooney viscosity (ML (ML _{1 + 4} )) of the high cis polybutadiene is 40 to 49, preferably 40 to 47. When the Mooney viscosity is larger than the above range, the kneading processability is lowered, and when it is smaller than the above range, the wear resistance is lowered. In the present specification, the Mooney viscosity (ML) of high-cis polybutadiene is a value measured at 100 ° C. in accordance with JIS K6300-1: 2001.

The molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn) of the high cis polybutadiene is 3.0 to 3.9, preferably 3.0 to 3.6. When the molecular weight distribution is larger than the above range, the wear resistance is lowered, and when the molecular weight distribution is smaller than the above range, the kneading workability is lowered. In the present specification, the weight average molecular weight Mw and the number average molecular weight Mn of the high-cis polybutadiene are values measured by the methods described in the examples described later.

The weight average molecular weight Mw of the high cis polybutadiene is preferably 500,000 to 700,000, more preferably 550,000 to 650,000. When the molecular weight is larger than the above range, the kneading processability is lowered, and when it is smaller than the above range, the wear resistance may be lowered.

The number average molecular weight Mn of the high cis polybutadiene is preferably 120,000 to 250,000, more preferably 150,000 to 220,000. When the molecular weight is larger than the above range, the kneading processability is lowered, and when it is smaller than the above range, the wear resistance may be lowered.

The speed dependence index (the n value of the formula (1)) of Mooney viscosity of the high cis polybutadiene is 2.3 to 3.0, preferably 2.4 to 2.9, more preferably 2.4 to 2.8. When the n value is less than 2.3, the kneading property (dispersibility) of silica is deteriorated and the kneading processability is deteriorated, and when it is more than 3.0, the fuel efficiency is deteriorated.

The n value is measured in accordance with JIS K6300-1: 2001 by measuring the Mooney viscosity (ML) by changing the rotational speed (1 / min) of the rotor. It is the reciprocal of the slope of the straight line obtained by equation (1). Here, log (K) is an arbitrary number that means a straight intercept.
log (ML) = log (K) + n ⁻¹ × log (RS) Formula (1)
(However, RS represents the number of rotations per minute of the rotor, K represents an arbitrary number, and ML represents Mooney viscosity.)
In addition, the said Formula (1) can be obtained based on the theoretical formula (following Formula (2)) of the n-power rule with respect to a non-Newtonian flow.
γ = kτ ⁿ formula (2)
(Where γ: velocity gradient, τ: shear stress, k ⁻¹ = η: viscosity coefficient)

The n value is determined by the degree of branching and molecular weight distribution of polybutadiene and has no correlation with Mooney viscosity. The n value increases as the degree of branching and molecular weight distribution of polybutadiene increases, and the value n decreases as the degree of branching and molecular weight distribution of polybutadiene decreases.

In addition, since the manipulation of the range of the n value needs to optimize the molecular weight distribution, it can be performed in two steps as follows, for example. First, several types of polybutadiene having a small n value and different molecular weight are polymerized in the butadiene polymerization stage. Next, the n value is adjusted to an optimum range by blending several kinds of polybutadienes having different molecular weights to broaden the molecular weight distribution. The n value in the polymerization stage can be adjusted by the mixing molar ratio of the organoaluminum compound as a promoter and water. That is, by increasing the amount of water added to a predetermined amount of the organoaluminum compound, the mixing molar ratio decreases, and the n value tends to decrease as the mixing molar ratio decreases. The mixing molar ratio of the organoaluminum compound, which is a promoter in the polymerization stage, and water is preferably 2.0 or less, particularly preferably 1.0 to 1.5. When the mixing molar ratio exceeds 2.0, the n value becomes too large, and when it is less than 1.0, the polymerization activity may be remarkably lowered.

The ratio (Tcp / ML) of 5 mass% toluene solution viscosity (Tcp) and Mooney viscosity (ML) of the high cis polybutadiene is preferably 2.5 to 3.5, more preferably 2.5 to 3. 0. When Tcp / ML is larger than the above range, the cold flow property of the base rubber (high cis polybutadiene) becomes large, and when Tcp / ML is smaller than the above range, the wear resistance may be lowered. The viscosity of 5 mass% toluene solution (Tcp) was obtained by dissolving 2.28 g of high-cis polybutadiene in 50 ml of toluene, and then using a standard solution for calibrating viscometer (JIS Z8809) as a standard solution. 400 was used and measured at 25 ° C.

The cis content of the high cis polybutadiene is 95% by mass or more, preferably 97% by mass or more, and more preferably 98% by mass or more. When the cis content is smaller than the above range, the wear resistance is lowered. The cis content is calculated by infrared absorption spectrum analysis.

The high cis polybutadiene can be produced, for example, with a cobalt catalyst. Examples of the cobalt-based catalyst include a catalyst system comprising (a) a cobalt compound, (b) a halogen-containing organoaluminum compound, and (c) water.

As the cobalt compound, a cobalt salt or complex is preferably used. Particularly preferred are cobalt salts such as cobalt chloride, cobalt bromide, cobalt nitrate, cobalt octylate (ethylhexanoate), cobalt naphthenate, cobalt acetate and cobalt malonate, cobalt bisacetylacetonate and trisacetylacetate. Examples thereof include organic base complexes such as nates, ethyl acetoacetate cobalt, pyridine complexes and picoline complexes of cobalt salts, or ethyl alcohol complexes.

Examples of the halogen-containing organic aluminum include trialkylaluminum, dialkylaluminum chloride, dialkylaluminum bromide, alkylaluminum sesquichloride, alkylaluminum sesquibromide, and alkylaluminum dichloride.

Specific examples of the compound include trialkylaluminum such as trimethylaluminum, triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, and tridecylaluminum.

In addition, dialkylaluminum chlorides such as dimethylaluminum chloride and diethylaluminum chloride, organoaluminum halogen compounds such as sesquiethylaluminum chloride and ethylaluminum dichloride, hydrogenated organics such as diethylaluminum hydride, diisobutylaluminum hydride and sesquiethylaluminum hydride Aluminum compounds are also included. Two or more of these organoaluminum compounds can be used in combination.

The molar ratio (b) / (a) between the component (a) and the component (b) is preferably 0.1 to 5000, more preferably 1 to 2000.

The molar ratio (b) / (c) between the component (b) and the component (c) is preferably 0.7 to 5, more preferably 0.8 to 4, particularly preferably 1 to 3. is there.

In addition to butadiene monomer, isoprene, 1,3-pentadiene, 2-ethyl-1,3-butadiene, 2,3-dimethylbutadiene, 2-methylpentadiene, 4-methylpentadiene, conjugated dienes such as 2,4-hexadiene, ethylene Acyclic monoolefins such as propylene, butene-1, butene-2, isobutene, pentene-1, 4-methylpentene-1, hexene-1 and octene-1, cyclic monoolefins such as cyclopentene, cyclohexene and norbornene, and A small amount of aromatic vinyl compounds such as styrene and α-methylstyrene, non-conjugated diolefins such as dicyclopentadiene, 5-ethylidene-2-norbornene, and 1,5-hexadiene may be included.

The polymerization method is not particularly limited, and bulk polymerization (bulk polymerization) using a conjugated diene compound monomer such as 1,3-butadiene itself as a polymerization solvent, or solution polymerization can be applied. Solvents used in the solution polymerization include aromatic hydrocarbons such as toluene, benzene and xylene, aliphatic hydrocarbons such as n-hexane, butane, heptane and pentane, alicyclic hydrocarbons such as cyclopentane and cyclohexane, and the like. And olefinic hydrocarbons such as cis-2-butene and trans-2-butene, hydrocarbon solvents such as mineral spirit, solvent naphtha and kerosene, and halogenated hydrocarbon solvents such as methylene chloride. .

Among these, toluene, cyclohexane, or a mixture of cis-2-butene and trans-2-butene is preferably used.

The polymerization temperature is preferably in the range of -30 to 150 ° C, particularly preferably in the range of 30 to 100 ° C. The polymerization time is preferably in the range of 1 minute to 12 hours, particularly preferably 5 minutes to 5 hours.

After performing the polymerization for a predetermined time, the inside of the polymerization tank is released as necessary, and post-treatment such as washing and drying steps is performed to obtain the high-cis polybutadiene. In addition, as a commercial item of the said high cis polybutadiene, BR710 by Ube Industries, Ltd. is mentioned.

Content of the said high cis polybutadiene in 100 mass% of rubber components is 10 mass% or more, Preferably it is 20 mass% or more. If it is less than 10% by mass, sufficient fuel economy, wear resistance and kneading processability cannot be obtained. The content of the high cis polybutadiene is 70% by mass or less, preferably 60% by mass or less, more preferably 50% by mass or less. When it exceeds 70 mass%, sufficient wet grip performance cannot be obtained.

The total content of the conjugated diene polymer and the high-cis polybutadiene in 100% by mass of the rubber component is preferably 80% by mass or more, more preferably 90% by mass or more, and may be 100% by mass. If it is less than 80% by mass, the fuel economy, wet grip performance, wear resistance, and kneadability may not be obtained in a well-balanced manner.

Examples of other rubber components include conventional styrene-butadiene copolymer rubber, polybutadiene rubber (BR) other than the above high-cis polybutadiene, 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.

The rubber composition of the present invention contains silica. By blending silica together with the conjugated diene polymer and the high cis polybutadiene, the silica can be dispersed well, and the fuel economy, wet grip performance, wear resistance, and kneadability can be improved in a well-balanced manner. The silica is not particularly limited, and examples thereof include dry method silica (anhydrous silica), wet method silica (hydrous silica) and the like, and wet method silica is preferable because of its large number of silanol groups. Silica may be used alone or in combination of two or more.

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, and further preferably 150 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 200 m ² / g or less. When it exceeds 400 m ² / g, silica is difficult to disperse, and fuel economy and kneading workability tend to deteriorate.
The nitrogen adsorption specific surface area of silica is a value measured by the BET method according to ASTM D3037-81.

The content of silica is 5 parts by mass or more, preferably 10 parts by mass or more, more preferably 45 parts by mass or more 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. When it exceeds 150 parts by mass, kneadability tends to deteriorate.

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, abrasion resistance, and kneading | mixing workability can be improved with a high dimension and sufficient balance.

A silane coupling agent may be used in combination with the silica. As the silane coupling agent, any silane coupling agent conventionally used in combination with silica can be used in the rubber industry. For example, sulfide systems such as bis (3-triethoxysilylpropyl) tetrasulfide, 3 -Mercapto type such as mercaptopropyltrimethoxysilane, vinyl type such as vinyltriethoxysilane, amino type such as 3-aminopropyltriethoxysilane, glycidoxy type of γ-glycidoxypropyltriethoxysilane, 3-nitropropyltri Examples thereof include nitro compounds such as methoxysilane, and chloro compounds such as 3-chloropropyltrimethoxysilane. Among these, sulfide type is preferable, and bis (3-triethoxysilylpropyl) tetrasulfide is more preferable.

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 tends to be high and the kneading processability tends to deteriorate. 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.

In the present invention, known additives can be used in addition to the above components, such as sulfur vulcanizing agents; thiazole vulcanization accelerators, thiuram vulcanization accelerators, sulfenamide vulcanization accelerators, Vulcanization accelerators such as guanidine vulcanization accelerators; vulcanization activators such as stearic acid and zinc oxide; organic peroxides; carbon black, calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, etc. Examples include fillers; processing aids such as extender oils and lubricants; and 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.

Nitrogen adsorption specific surface area _(N 2 SA) of carbon black is usually 5 to 200 m ² / g, the lower limit is preferably ^{50 m} 2 / g, the upper limit is 150 meters ² / g. Carbon black has a dibutyl phthalate (DBP) absorption amount of usually 5 to 300 ml / 100 g, preferably a lower limit of 80 ml / 100 g and an upper limit of 180 ml / 100 g. 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 commercial product, Tokai Carbon Co., Ltd. trade name Seast 6, Seast 7HM, Seast KH, Degussa trade name CK3, Special Black 4A, etc. can be used.

When carbon black is blended in the rubber composition of the present invention, the content of carbon black is preferably 2 parts by mass or more with respect to 100 parts by mass of the rubber component. If the amount is less than 2 parts by mass, the effect of blending carbon black may not be sufficiently obtained. Further, the carbon black content is preferably 20 parts by mass or less, more preferably 10 parts by mass or less. If it exceeds 20 parts by mass, the fuel efficiency tends to deteriorate.

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 balance between low fuel consumption, wet grip performance, wear resistance, and kneading processability, and can provide a remarkable improvement effect of these performances.

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

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

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

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

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

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

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

4). 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 Comparative Example 1 being 100. Larger values indicate lower rolling resistance and better fuel efficiency.

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

7). Abrasion resistance (LAT abrasion test)
Using a LAT tester (Laboratory Abbreviation 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 volume loss amount of Comparative Example 1 was set to 100, and the results of each formulation were displayed as an index. The larger the value, the better the wear resistance.

8). Kneading processability Using a 1.7 L Banbury mixer manufactured by Kobe Steel, Ltd., materials other than sulfur and vulcanization accelerators at a predetermined filling rate of 5 at 150 ° C. (starting temperature: 50 ° C.). When kneading for a minute, the time until the torque rises was measured. The larger the index, the better the kneadability.

Production Example 1 (Synthesis of Polymer 1)
It washed 20 liter stainless steel polymerization reactor, and dried, flushed with dry nitrogen, hexane (specific gravity 0.68g ^/ cm 3) 10.2kg, 1,3- butadiene 547 g, styrene 173 g, tetrahydrofuran 6. 1 ml and ethylene glycol diethyl ether 5.0 ml were charged into the polymerization reactor. Next, 10.5 mmol of bis (diethylamino) methylvinylsilane and 14.9 mmol of n-butyllithium were added as a cyclohexane solution and an n-hexane solution, respectively, to initiate polymerization.
The stirring rate was 130 rpm, the temperature in the polymerization reactor was 65 ° C., and 1,3-butadiene and styrene were copolymerized for 3 hours while continuously supplying the monomer into the polymerization reactor. The supply amount of 1,3-butadiene in the total polymerization was 821 g, and the supply amount of styrene was 259 g.
Next, the obtained polymer solution was stirred at a stirring speed of 130 rpm, 10.5 mmol of N- (3-dimethylaminopropyl) acrylamide was added, and the mixture was 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)
It washed 20 liter stainless steel polymerization reactor, and dried, flushed with dry nitrogen, hexane (specific gravity 0.68g ^/ cm 3) 10.2kg, 1,3- butadiene 547 g, styrene 173 g, tetrahydrofuran 6. 1 ml and ethylene glycol diethyl ether 5.0 ml were charged into the polymerization reactor. Next, 12.9 mmol of n-butyllithium was added as an n-hexane solution, and 1,3-butadiene and styrene were copolymerized for 0.83 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 reactor.
After the polymerization for 0.83 hours, 10.5 mmol of bis (diethylamino) methylvinylsilane was added as a cyclohexane solution, and the mixture was charged into the polymerization reactor under the conditions of a stirring speed of 130 rpm and a polymerization reactor temperature of 65 ° C.
Next, the monomer was continuously fed into the polymerization reactor, and 1,3-butadiene and styrene were copolymerized for 1.67 hours. During the polymerization, the stirring speed was 130 rpm, and the temperature in the polymerization reactor was 65 ° C. The supply amount of 1,3-butadiene in the total polymerization was 821 g, and the supply amount of styrene was 259 g.
Next, the obtained polymer solution was stirred at a stirring speed of 130 rpm, 10.5 mmol of N- (3-dimethylaminopropyl) acrylamide was added, and the mixture was 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. 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)
It washed 20 liter stainless steel polymerization reactor, and dried, flushed with dry nitrogen, hexane (specific gravity 0.68g ^/ cm 3) 10.2kg, 1,3- butadiene 547 g, styrene 173 g, tetrahydrofuran 6. 1 ml and ethylene glycol diethyl ether 5.0 ml were charged into the polymerization reactor. Next, 10.5 mmol of bis (diethylamino) methylvinylsilane and 13.4 mmol of n-butyllithium were added as a cyclohexane solution and an n-hexane solution, respectively, and 1,3-butadiene and styrene were copolymerized for 1 hour. During the polymerization, the stirring speed was 130 rpm, the temperature in the polymerization reactor was 65 ° C., and the monomer was continuously fed into the polymerization reactor.
After the 0.5 hour polymerization, 10.5 mmol of bis (diethylamino) methylvinylsilane was added as a cyclohexane solution, and the mixture was charged into the polymerization reactor under the conditions of a stirring speed of 130 rpm and a polymerization reactor temperature of 65 ° C.
Next, the monomer was continuously supplied into the polymerization reactor, and 1,3-butadiene and styrene were copolymerized for 0.5 hour. During the polymerization, the stirring speed was 130 rpm, and the temperature in the polymerization reactor was 65 ° C.
After the 0.5 hour polymerization, 10.5 mmol of bis (diethylamino) methylvinylsilane was added as a cyclohexane solution, and the mixture was charged into the polymerization reactor under the conditions of a stirring speed of 130 rpm and a polymerization reactor temperature of 65 ° C.
Next, the monomer was continuously fed into the polymerization reactor, and 1,3-butadiene and styrene were copolymerized for 1.5 hours. During the polymerization, the stirring speed was 130 rpm, and the temperature in the polymerization reactor was 65 ° C. The supply amount of 1,3-butadiene in the total polymerization was 821 g, and the supply amount of styrene was 259 g.
Next, the obtained polymer solution was stirred at a stirring speed of 130 rpm, 10.5 mmol of N- (3-dimethylaminopropyl) acrylamide was added, and the mixture was 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. 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 0.017 mmol / g polymer per polymer unit mass. there were.

Production Example 4 (Synthesis of Polymer 4)
It washed 20 liter stainless steel polymerization reactor, and dried, flushed with dry nitrogen, hexane (specific gravity 0.68g ^/ cm 3) 10.2kg, 1,3- butadiene 547 g, styrene 173 g, tetrahydrofuran 6. 1 ml and ethylene glycol diethyl ether 5.0 ml were charged into the polymerization reactor. Next, 10.5 mmol of bis {di (n-butyl) amino} methylvinylsilane and 13.4 mmol of n-butyllithium were added as a cyclohexane solution and an n-hexane solution, respectively, to initiate polymerization.
The stirring rate was 130 rpm, the temperature in the polymerization reactor was 65 ° C., and 1,3-butadiene and styrene were copolymerized for 3 hours while continuously supplying the monomer into the polymerization reactor. The supply amount of 1,3-butadiene in the total polymerization was 821 g, and the supply amount of styrene was 259 g.
Next, the obtained polymer solution was stirred at a stirring speed of 130 rpm, 10.5 mmol of N- (3-dimethylaminopropyl) acrylamide was added, and the mixture was 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, 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 5 (Synthesis of Polymer 5)
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 reactor. 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 reactor. 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. 5 was recovered. The evaluation results of the polymer 5 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 6 (Synthesis of Polymer 6)
It washed 20 liter stainless steel polymerization reactor, and dried, flushed with dry nitrogen, hexane (specific gravity 0.68g ^/ cm 3) 10.2kg, 1,3- butadiene 547 g, styrene 173 g, tetrahydrofuran 6. 1 ml and ethylene glycol diethyl ether 5.0 ml were charged into the polymerization reactor. Next, 10.5 mmol of bis (diethylamino) methylvinylsilane and 14.9 mmol of n-butyllithium were added as a cyclohexane solution and an n-hexane solution, respectively, to initiate polymerization.
The stirring rate was 130 rpm, the temperature in the polymerization reactor was 65 ° C., and 1,3-butadiene and styrene were copolymerized for 3 hours while continuously supplying the monomer into the polymerization reactor. The supply amount of 1,3-butadiene in the total polymerization was 821 g, and the supply amount of styrene was 259 g.
Next, 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. 6 was recovered. 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.

Production Example 7 (Synthesis of Polymer 7)
It washed 20 liter stainless steel polymerization reactor, and dried, flushed with dry nitrogen, hexane (specific gravity 0.68g ^/ cm 3) 10.2kg, 1,3- butadiene 547 g, styrene 173 g, tetrahydrofuran 6. 1 ml and ethylene glycol diethyl ether 5.0 ml were charged into the polymerization reactor. Next, 14.9 mmol of n-butyllithium was added as an n-hexane solution to initiate polymerization.
The stirring rate was 130 rpm, the temperature in the polymerization reactor was 65 ° C., and 1,3-butadiene and styrene were copolymerized for 3 hours while continuously supplying the monomer into the polymerization reactor. The supply amount of 1,3-butadiene in the total polymerization was 821 g, and the supply amount of styrene was 259 g.
Next, the obtained polymer solution was stirred at a stirring speed of 130 rpm, 10.5 mmol of N- (3-dimethylaminopropyl) acrylamide was added, and the mixture was 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. 7 was recovered. The evaluation results of the polymer 7 are shown in Table 1. In addition, since the polymer 7 did not use the compound represented by Formula (IV) at the time of a synthesis | combination, the polymer 7 did not contain the structural unit represented by Formula (I).

Production Example 8 (Synthesis of Polymer 8)
It washed 20 liter stainless steel polymerization reactor, and dried, flushed with dry nitrogen, hexane (specific gravity 0.68g ^/ cm 3) 10.2kg, 1,3- butadiene 547 g, styrene 173 g, tetrahydrofuran 6. 1 ml and ethylene glycol diethyl ether 5.0 ml were charged into the polymerization reactor. Next, 14.9 mmol of n-butyllithium was added as an n-hexane solution) to initiate polymerization.
The stirring rate was 130 rpm, the temperature in the polymerization reactor was 65 ° C., and 1,3-butadiene and styrene were copolymerized for 3 hours while continuously supplying the monomer into the polymerization reactor. The supply amount of 1,3-butadiene in the total polymerization was 821 g, and the supply amount of styrene was 259 g.
Next, 20 ml of hexane solution containing 0.54 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. 8 was recovered. The evaluation results of the polymer 8 are shown in Table 1. In addition, since the polymer 8 did not use the compound represented by Formula (IV) at the time of a synthesis | combination, it did not contain the structural unit represented by Formula (I).

Production Example 9 (Synthesis of Polymer 9)
It washed 20 liter stainless steel polymerization reactor, and dried, flushed with dry nitrogen, hexane (specific gravity 0.68g ^/ cm 3) 10.2kg, 1,3- butadiene 547 g, styrene 173 g, tetrahydrofuran 6. 1 ml and ethylene glycol diethyl ether 5.0 ml were charged into the polymerization reactor. Next, 10.5 mmol of bis (diethylamino) methylvinylsilane and 14.9 mmol of n-butyllithium were added as a cyclohexane solution and an n-hexane solution, respectively, to initiate polymerization.
The stirring rate was 130 rpm, the temperature in the polymerization reactor was 65 ° C., and 1,3-butadiene and styrene were copolymerized for 3 hours while continuously supplying the monomer into the polymerization reactor. The supply amount of 1,3-butadiene in the total polymerization was 821 g, and the supply amount of styrene was 259 g.
Next, the obtained polymer solution was stirred at a stirring speed of 130 rpm, 10.5 mmol of N- (3-dimethylaminopropyl) acrylamide was added, and the mixture was 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 9. The evaluation results of the polymer 9 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.
BR1: Ubepol BR150B manufactured by Ube Industries, Ltd.
BR2: Ubepol BR150L manufactured by Ube Industries, Ltd.
BR3: Ubepol BR230 manufactured by Ube Industries, Ltd.
BR4: Ubepol BR710 manufactured by Ube Industries, Ltd. (high-cis polybutadiene rubber produced by the method described in Japanese Patent No. 4124273)
Polymers 1-9: Polymers 1-9 obtained by Production Examples 1-9 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 N220 manufactured by Mitsubishi Chemical Corporation (N ₂ SA: 114 m ² / g, DBP absorption: 114 ml / 100 g)
Oil: X-140 manufactured by Japan Energy 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.

Table 2 summarizes the results of analysis of BR1 to BR4 by the measurement method described above. Note that BR4 corresponds to the high-cis polybutadiene.

(Examples and Comparative Examples)
In accordance with the contents shown in Tables 3 and 4, 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 Co., Ltd. (Start Temperature: 50 ° C.) to obtain a kneaded product. 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. Each test result is shown in Tables 3 and 4.

As shown in Tables 3 and 4, a specific high-cis polybutadiene (BR4), a specific amount of a rubber component containing specific amounts of conjugated diene polymers (polymers 1 to 4 and 9), and a specific amount of silica are blended. In the example, compared with the comparative example, the fuel economy, wet grip performance, wear resistance, and kneadability could be improved in a balanced manner.

From the results of Comparative Examples 1, 5, 9, and Example 1, by using a specific high-cis polybutadiene and a specific conjugated diene polymer in combination, low fuel consumption, wet grip performance, wear resistance, kneading processability It was found that (especially kneadability) can be improved synergistically.

On the other hand, even when a specific high-cis polybutadiene and a styrene butadiene rubber (polymer 6) in which only the main chain is modified are used in combination, the wet grip performance and the wear resistance are compared with those of Comparative Examples 1, 3, 5, and 7. It was found that kneadability cannot be improved synergistically. And the comparative example 7 which used specific high cis polybutadiene and the polymer 6 together used was inferior in performance compared with the Example. Similarly, from the comparison of Comparative Examples 1, 4, 5, and 8, even when a specific high-cis polybutadiene and a styrene butadiene rubber (polymer 7) modified only at the terminal are used in combination, wet grip performance and abrasion resistance are used. It was found that kneadability cannot be improved synergistically. And the comparative example 8 which used specific high cis polybutadiene and the polymer 7 together used was inferior in performance compared with the Example.

Moreover, the comparative examples 9-11 which used BR other than specific high cis polybutadiene together with the specific conjugated diene polymer were significantly inferior to the examples.

Further, compared with Comparative Example 1 and Comparative Example 5, Comparative Example 2 and Comparative Example 6, Comparative Example 3 and Comparative Example 7, Comparative Example 4 and Comparative Example 8, a specific high-cis polybutadiene was replaced with BR1 in an unmodified manner. It was found that even when used in combination with styrene butadiene rubber, styrene butadiene rubber modified only at the terminal, or styrene butadiene rubber modified only in the main chain, the effect of improving wet grip performance cannot be obtained.

Claims (10)

Containing a rubber component and silica,
Among 100% by mass of the rubber component, (A) Mooney viscosity (ML): 40 to 49, (B) molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn): 3.0 to 3.9 and (C) Rate-dependent index of Mooney viscosity (n value of formula (1)): satisfying the requirement of 2.3 to 3.0, and the content of high cis polybutadiene having a cis content of 95% by mass or more is 10 to 70% by mass %
A conjugated diene polymer having a structural unit based on a conjugated diene and a structural unit represented by the following formula (I), wherein at least one end of the polymer is modified with a compound represented by the following formula (II): The content is 30 to 90% by mass,
Content of the said silica with respect to 100 mass parts of said rubber components is 5-150 mass parts, The rubber composition characterized by the above-mentioned.
log (ML) = log (K) + n ⁻¹ × log (RS) Formula (1)
(However, RS represents the number of rotations per minute of the rotor, K represents an arbitrary number, and ML represents Mooney viscosity.)

[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, R ³ represents a hydrogen atom, a hydrocarbyl group having 1 to 6 carbon atoms, or a substituted hydrocarbyl group having 1 to 6 carbon atoms, and A ¹ represents , An oxygen atom or a —NR ⁴ — group (R ⁴ represents a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms), and A ² represents a functional group having a nitrogen atom and / or an oxygen atom. Represent. ] The rubber composition according to claim ^1, wherein R ¹ and R ^{2 in} the formula (Ia) are hydrocarbyl groups having 1 to 6 carbon atoms. The rubber composition according to claim 1 or 2, wherein ^two of X ¹ , X ² and X ^{3 in} the formula (I) are a group or a hydroxyl group represented by the formula (Ia). The rubber composition according to claim 1, wherein A ^{2 in the} formula (II) is a group or a hydroxyl group represented by the following formula (III).

[Wherein, R ⁵ and R ⁶ 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 ⁵ and R ⁶ may be bonded to form a ring structure together with the nitrogen atom, and R ⁵ and R ⁶ may be the same group bonded to 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. The ratio (Tcp / ML) of 5 mass% toluene solution viscosity (Tcp) and Mooney viscosity (ML) of the high-cis polybutadiene is 2.5 to 3.5. The rubber composition as described in 2. The rubber composition according to claim 1, wherein the high-cis polybutadiene has an Mw of 500,000 to 700,000 and an Mn of 120,000 to 250,000. 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 8, wherein the rubber composition is used as a rubber composition for a tread. The pneumatic tire produced using the rubber composition in any one of Claims 1-9.