JP2021165356A - Modified conjugated diene polymer, method for producing the same, rubber composition, and tire - Google Patents

Abstract

To provide a modified conjugated diene polymer which is excellent in processability when made into a vulcanizate and whose vulcanizate is excellent in abrasion resistance and low hysteresis loss performance.SOLUTION: The modified conjugated diene polymer comprises: a conjugated diene polymer chain having a branched structure; and a modifier residue derived from a modifier having a predetermined group. The modifier is a compound represented by the following formula (A) (where R1 and R2 each independently represent a C1-20 hydrocarbyl group; R3 represents a C1-20 alkanediyl group; R4 and R5 each independently represent a hydrogen atom, a C1-20 alkyl group or a C6-20 aryl group; n represents an integer of 1-3; and a plurality of R1's or R2's may be the same as or different from each other).SELECTED DRAWING: None

Description

The present invention relates to a conjugated diene polymer, a method for producing a conjugated diene polymer, a rubber composition, and a tire.

Conventionally, there has been an increasing demand for fuel efficiency of automobiles, and improvement of rubber materials used for automobile tires, particularly tire treads in contact with road surfaces, has been required.

In recent years, there has been a tendency for automobiles to be lighter due to resinification of members due to increasing demands for fuel efficiency regulations for automobiles, and there is an increasing demand for thinner tire members from the viewpoint of weight reduction.

In order to reduce the weight of a tire, it is necessary to reduce the thickness of the tread portion in contact with a road surface having a particularly high material ratio, and a rubber material having more excellent wear resistance than before is required.

Further, in order to reduce the energy loss due to the tire during traveling, the rubber material used for the tire tread is required to have a small rolling resistance, that is, a material having a low hysteresis loss property.

Examples of the rubber material that meets the above-mentioned requirements include a rubber composition containing a rubber-like polymer and a reinforcing filler such as carbon black and silica.

Further, as an improvement of the rubber-like polymer itself, for example, a modified conjugated diene polymer obtained by reacting an active terminal of a conjugated diene polymer with a modifier containing a methyleneamino group has been proposed. While improving the reactivity between the diene-based copolymer and silica to improve the low hysteresis loss performance, the wear resistance is improved (see, for example, Patent Document 1).

Patent No. 411590

Here, when a rubber composition containing silica is used, the low hysteresis loss property is improved. Further, by introducing a functional group having affinity or reactivity with silica into the molecular terminal portion of the highly motility rubber-like polymer, the dispersibility of silica in the rubber composition can be improved, and further. By bonding with silica particles, the motility of the molecular end of the rubber-like polymer can be reduced, hysteresis loss can be reduced, and wear resistance can be improved.

However, it is not enough to use a reinforcing filler such as silica, and it is necessary to improve the rubber-like polymer itself. However, in the modified branched conjugated diene-based copolymer using a modifying agent containing a methyleneamino group as described in Patent Document 1, if the Mooney viscosity is high, the workability is sufficiently deteriorated and the low hysteresis loss is sufficiently exhibited. Will disappear.

Therefore, in the present invention, although it has a residue derived from a modifier containing a methyleneamino group, it is excellent in processability when it is made into a vulcanized product, and has low wear resistance and low when it is made into a vulcanized product. An object of the present invention is to provide a modified conjugated diene-based polymer having excellent hysteresis loss performance.

As a result of diligent research and study to solve the above-mentioned problems of the prior art, the present inventors have obtained a conjugated diene-based polymer chain having a branched structure and a modifier residue derived from a predetermined modifier having a predetermined group. The present invention was completed by finding that a modified conjugated diene-based polymer having a group is excellent in processability when made into a vulcanized product, low hysteresis loss property when made into a vulcanized product, and excellent wear resistance. I came to let you.

（式中、Ｒ¹及びＲ²は、それぞれ独立して炭素数１〜２０のヒドロカルビル基を示し、Ｒ³は、炭素数１〜２０のアルカンジイル基を示し、Ｒ⁴及びＲ⁵は、それぞれ独立して水素原子、炭素数１〜２０のアルキル基、又は炭素数６〜２０のアリール基を示し、ｎは、１〜３の整数である。複数のＲ¹及びＲ²のいずれかは、それらが互いに同一でも異なっていてもよい。）
〔２〕
変性率が、５０質量％以上である、〔１〕に記載の変性共役ジエン系重合体。
〔３〕
粘度検出器付きＧＰＣ−光散乱法測定法による絶対分子量が、４０×１０⁴以上５０００×１０⁴以下であり、
前記粘度検出器付きＧＰＣ−光散乱法測定法による分岐度（Ｂｎ）が、３以上である、
〔１〕又は〔２〕に記載の変性共役ジエン系重合体。
〔４〕
下記式（１）及び／又は下記式（２）で表される、変性共役ジエン系重合体。

（式中、（Ａ／Ｂ／Ｃ）はＡとＢとＣとのブロック又はランダム共重合体鎖であることを示し、Ａは、共役ジエン系重合体鎖又はそれの水素添加物を示し、Ｂは、芳香族ビニル化合物単位、Ｃは、下記式（３）又は下記式（４）で表される化合物に由来する構造単位を示し、ｎは、１〜２０の整数であり、Ｒ¹は、炭素数１〜２０のアルキル基又は炭素数６〜２０のアリール基を示し、Ｒ²及びＲ³は、それぞれ独立して水素原子、炭素数１〜２０のアルキル基、又は炭素数６〜２０のアリール基を示し、Ｒ⁴及びＲ⁵は、それぞれ独立して炭素数１〜２０のアルキル基又は炭素数６〜２０のアリール基を示し、ｍは、１〜３の整数であり、ｌは、１〜２０の整数であり、ｏは、１から２０の整数である。複数の場合のＲ¹は、それらが互いに同一でも異なっていてもよい。）

（式中、Ｑ¹は、水素原子、並びにその一部分に分岐構造を有していてもよい、炭素数１〜２０のアルキル基及び炭素数６〜２０のアリール基からなる群より選ばれるいずれかを示し、Ｘ¹、Ｘ²、及びＸ³は、それぞれ独立して単結合、又は炭素原子、水素原子、窒素原子、硫黄原子、及び酸素原子からなる群より選ばれるいずれかを含有する有機基を示し、Ｙ¹、Ｙ²、及びＹ³は、それぞれ独立して炭素数１〜２０のアルキル基、炭素数１〜２０のアルコキシ基、及びハロゲン原子からなる群より選ばれるいずれかを示す。）
〔５〕
その総量（１００質量％）に対して、〔１〕〜〔４〕のいずれかに記載の変性共役ジエン系重合体を１０質量％以上含むゴム成分と、
前記ゴム成分１００質量部に対して、充填剤を５．０質量部以上１５０質量部以下と、
を含有する、ゴム組成物。
〔６〕
アルカリ金属化合物又はアルカリ土類金属化合物を重合開始剤として用い、共役ジエン化合物、又は共役ジエン化合物及び芳香族ビニル化合物、を重合又は共重合し、活性末端を有する共役ジエン系重合体を得る重合工程と、
前記共役ジエン系重合体の前記活性末端に、スチレン誘導体を反応させて、分岐構造を導入する分岐化工程と、
分岐化工程後の活性末端に、下記式（Ａ）で表される化合物を反応させる、変性工程と、を有する、変性共役ジエン系重合体の製造方法。

（式中、Ｒ¹及びＲ²は、それぞれ独立して炭素数１〜２０のヒドロカルビル基を示し、Ｒ³は、炭素数１〜２０のアルカンジイル基を示し、Ｒ⁴及びＲ⁵は、それぞれ独立して水素原子、炭素数１〜２０のアルキル基、又は炭素数６〜２０のアリール基を示し、ｎは、１〜３の整数である。複数のＲ¹及びＲ²のいずれかは、それらが互いに同一でも異なっていてもよい。）
〔７〕
前記スチレン誘導体は、下記式（３）及び／又は下記式（４）で表される化合物である、〔６〕に記載の変性共役ジエン系重合体の製造方法。

（式中、Ｑ¹は、水素原子、並びにその一部分に分岐構造を有していてもよい、炭素数１〜２０のアルキル基及び炭素数６〜２０のアリール基からなる群より選ばれるいずれかを示し、Ｘ¹、Ｘ²、及びＸ³は、それぞれ独立して単結合、又は炭素原子、水素原子、窒素原子、硫黄原子、及び酸素原子からなる群より選ばれるいずれかを含有する有機基を示し、Ｙ¹、Ｙ²、及びＹ³は、それぞれ独立して炭素数１〜２０のアルキル基、炭素数１〜２０のアルコキシ基、及びハロゲン原子からなる群より選ばれるいずれかを示す。）
〔８〕
前記スチレン誘導体は、前記式（３）で表される化合物を含み、
前記式（３）中、Ｑ¹は、水素原子を示す、〔７〕に記載の変性共役ジエン系重合体の製造方法。
〔９〕
前記スチレン誘導体は、前記式（３）で表される化合物を含み、
前記式（３）中、Ｑ¹は、水素原子を示し、Ｙ¹は、炭素数１〜２０のアルコキシ基又はハロゲン原子を示す、〔７〕に記載の変性共役ジエン系重合体の製造方法。
〔１０〕
前記スチレン誘導体は、前記式（４）で表される化合物を含み、
前記式（４）中、Ｙ²は、炭素数１〜２０のアルコキシ基又はハロゲン原子を示し、Ｙ³は、炭素数１〜２０のアルコキシ基又はハロゲン原子を示す、〔７〕に記載の変性共役ジエン系重合体の製造方法。
〔１１〕
前記スチレン誘導体は、前記式（３）で表される化合物を含み、
前記式（３）中、Ｑ¹は、水素原子を示し、Ｙ¹は、炭素数１〜２０のアルコキシ基を示す、〔７〕に記載の変性共役ジエン系重合体の製造方法。
〔１２〕
前記スチレン誘導体は、前記式（３）で表される化合物を含み、
前記式（３）中、Ｑ¹は、水素原子を示し、Ｘ¹は、単結合を示し、Ｙ１は、炭素数１〜２０のアルコキシ基を示す、〔７〕に記載の変性共役ジエン系重合体の製造方法。
〔１３〕
前記スチレン誘導体は、前記式（４）で表される化合物を含み、
前記式（４）中、Ｘ²は、単結合を示し、Ｙ²は、炭素数１〜２０のアルコキシ基又はハロゲン原子を示し、Ｘ³は、単結合を示し、Ｙ³は、炭素数１〜２０のアルコキシ基又はハロゲン原子を示す、〔７〕に記載の変性共役ジエン系重合体の製造方法。
〔１４〕
〔５〕に記載のゴム組成物を含有する、タイヤ。 That is, the present invention is as follows.
[1]
Monovalent group having a conjugated diene polymer chain having a branched structure, in group "-CR ¹ = N-A ^1" (wherein, R ¹ represents a hydrogen atom or a hydrocarbyl group, an A ¹ is an alkoxysilyl group A modified conjugated diene polymer having a modifier residue derived from a modifier having ().
The modifier is a modified conjugated diene polymer which is a compound represented by the following formula (A).

(In the formula, R ¹ and R ² independently represent a hydrocarbyl group having 1 to 20 carbon atoms, R ³ represents an alkanediyl group having 1 to 20 carbon atoms, and R ⁴ and R ⁵ represent an alkanediyl group having 1 to 20 carbon atoms, respectively. It independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and n is an integer of ^{1 to 3.} Any one of a plurality of R 1 and R 2 may be used. They may be the same or different from each other.)
[2]
The modified conjugated diene polymer according to [1], wherein the modification rate is 50% by mass or more.
[3]
The absolute molecular weight by the GPC-light scattering measurement method with a viscosity detector is 40 × 10 ⁴ or more and 5000 × 10 ⁴ or less.
The degree of branching (Bn) by the GPC-light scattering measurement method with a viscosity detector is 3 or more.
The modified conjugated diene polymer according to [1] or [2].
[4]
A modified conjugated diene-based polymer represented by the following formula (1) and / or the following formula (2).

(In the formula, (A / B / C) indicates a block or random copolymer chain of A, B and C, and A indicates a conjugated diene polymer chain or a hydrogenated product thereof. B is an aromatic vinyl compound unit, C is a structural unit derived from a compound represented by the following formula (3) or the following formula (4), n is an integer of 1 to 20, and R ¹ is an integer. , An alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and R ² and R ³ are independently hydrogen atoms, an alkyl group having 1 to 20 carbon atoms, or 6 to 20 carbon atoms, respectively. R ⁴ and R ⁵ each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, m is an integer of 1 to 3, and l is an integer of 1 to 3. , 1 to 20 and o is an integer from 1 to 20. In the case of a plurality of R ¹ , they may be the same as or different from each other.)

(In the formula, Q ¹ is selected from the group consisting of an alkyl group having 1 to 20 carbon atoms and an aryl group having 6 to 20 carbon atoms, which may have a branched structure in a hydrogen atom and a part thereof. , X ¹ , X ² and X ³ are independent single bonds or organic groups containing any one selected from the group consisting of carbon atom, hydrogen atom, nitrogen atom, sulfur atom and oxygen atom. , Y ¹ , Y ² and Y ³ are each independently selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom. )
[5]
A rubber component containing 10% by mass or more of the modified conjugated diene polymer according to any one of [1] to [4] with respect to the total amount (100% by mass).
With respect to 100 parts by mass of the rubber component, the filler was added in an amount of 5.0 parts by mass or more and 150 parts by mass or less.
A rubber composition containing.
[6]
A polymerization step of polymerizing or copolymerizing a conjugated diene compound, or a conjugated diene compound and an aromatic vinyl compound, using an alkali metal compound or an alkaline earth metal compound as a polymerization initiator to obtain a conjugated diene polymer having an active terminal. When,
A branching step of reacting a styrene derivative with the active terminal of the conjugated diene polymer to introduce a branched structure, and
A method for producing a modified conjugated diene-based polymer, which comprises a modification step of reacting an active terminal after the branching step with a compound represented by the following formula (A).

(In the formula, R ¹ and R ² independently represent a hydrocarbyl group having 1 to 20 carbon atoms, R ³ represents an alkanediyl group having 1 to 20 carbon atoms, and R ⁴ and R ⁵ represent an alkanediyl group having 1 to 20 carbon atoms, respectively. It independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and n is an integer of ^{1 to 3.} Any one of a plurality of R 1 and R 2 may be used. They may be the same or different from each other.)
[7]
The method for producing a modified conjugated diene polymer according to [6], wherein the styrene derivative is a compound represented by the following formula (3) and / or the following formula (4).

(In the formula, Q ¹ is selected from the group consisting of an alkyl group having 1 to 20 carbon atoms and an aryl group having 6 to 20 carbon atoms, which may have a branched structure in a hydrogen atom and a part thereof. , X ¹ , X ² and X ³ are independent single bonds or organic groups containing any one selected from the group consisting of carbon atom, hydrogen atom, nitrogen atom, sulfur atom and oxygen atom. , Y ¹ , Y ² and Y ³ are each independently selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom. )
[8]
The styrene derivative contains a compound represented by the formula (3).
In the formula (3), Q ¹ represents a hydrogen atom, process for producing a modified conjugated diene polymer according to [7].
[9]
The styrene derivative contains a compound represented by the formula (3).
The method for producing a modified conjugated diene polymer according to [7], wherein in the formula (3), Q ¹ represents a hydrogen atom and Y ¹ represents an alkoxy group or a halogen atom having 1 to 20 carbon atoms.
[10]
The styrene derivative contains a compound represented by the formula (4).
In the formula (4), Y ² represents an alkoxy group or a halogen atom having 1 to 20 carbon atoms, and Y ³ represents an alkoxy group or a halogen atom having 1 to 20 carbon atoms, according to [7]. A method for producing a conjugated diene polymer.
[11]
The styrene derivative contains a compound represented by the formula (3).
The method for producing a modified conjugated diene polymer according to [7], wherein in the formula (3), Q ¹ represents a hydrogen atom and Y ^{1 represents an alkoxy group having 1 to 20 carbon atoms.}
[12]
The styrene derivative contains a compound represented by the formula (3).
In the above formula (3), Q ¹ represents a hydrogen atom, X ¹ represents a single bond, and Y 1 represents an alkoxy group having 1 to 20 carbon atoms. The modified conjugated diene system weight according to [7]. Manufacturing method of coalescence.
[13]
The styrene derivative contains a compound represented by the formula (4).
In the above formula (4), X ² represents a single bond, Y ² represents an alkoxy group or a halogen atom having 1 to 20 carbon atoms, X ³ represents a single bond, and Y ³ has 1 carbon atom. The method for producing a modified conjugated diene-based polymer according to [7], which exhibits ~ 20 alkoxy groups or halogen atoms.
[14]
A tire containing the rubber composition according to [5].

According to the modified conjugated diene polymer according to the present invention, it has excellent processability when it is made into a vulcanized product, and has excellent wear resistance and low hysteresis loss performance when it is made into a vulcanized product.

Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail, but the present invention is not limited thereto, and various modifications are made without departing from the gist thereof. Is possible.

式中、Ｒ¹及びＲ²は、それぞれ独立して炭素数１〜２０のヒドロカルビル基を示し、Ｒ³は、炭素数１〜２０のアルカンジイル基を示し、Ｒ⁴及びＲ⁵は、それぞれ独立して水素原子、炭素数１〜２０のアルキル基、又は炭素数６〜２０のアリール基を示し、ｎは、１〜３の整数である。複数のＲ¹及びＲ²のいずれかは、それらが互いに同一でも異なっていてもよい。 The modified conjugated diene-based polymer of the present embodiment has a conjugated diene-based polymer chain having a branched structure and a group "-CR ¹ = ^{NA 1} " (in the formula, R ¹ represents a hydrogen atom or a hydrocarbon group. A ¹ has a modifier residue derived from a modifier having a monovalent group having an alkoxysilyl group). The denaturing agent is a compound represented by the following formula (A).

In the formula, R ¹ and R ² independently represent a hydrocarbyl group having 1 to 20 carbon atoms, R ³ represents an alkanediyl group having 1 to 20 carbon atoms, and R ⁴ and R ⁵ are independent of each other. It represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and n is an integer of 1 to 3 carbon atoms. The plurality of R ¹ and R ² may be the same or different from each other.

式中、（Ａ／Ｂ／Ｃ）はＡとＢとＣとのランダム共重合体鎖であることを示し、Ａは、共役ジエン系重合体鎖又はそれの水素添加物を示し、Ｂは、芳香族ビニル化合物単位、Ｃは、下記式（３）又は下記式（４）で表される化合物に由来する構造単位を示し、ｎは、１〜２０の整数であり、Ｒ¹は、炭素数１〜２０のアルキル基又は炭素数６〜２０のアリール基を示し、Ｒ²及びＲ³は、それぞれ独立して水素原子、炭素数１〜２０のアルキル基、又は炭素数６〜２０のアリール基を示し、Ｒ⁴及びＲ⁵は、それぞれ独立して炭素数１〜２０のアルキル基又は炭素数６〜２０のアリール基を示し、ｍは、１〜３の整数であり、ｌは、１〜２０の整数であり、ｏは、１から２０の整数である。複数の場合のＲ¹は、それらが互いに同一でも異なっていてもよい。 The modified conjugated diene polymer is preferably a modified conjugated diene polymer represented by the following formula (1) and / or the following formula (2) from the viewpoint of surely exerting the action and effect of the present invention.

In the formula, (A / B / C) indicates a random copolymer chain of A, B and C, A indicates a conjugated diene polymer chain or a hydrogenated product thereof, and B indicates a hydrogenated product thereof. The aromatic vinyl compound unit, C, represents a structural unit derived from the compound represented by the following formula (3) or the following formula (4), n is an integer of 1 to 20, and R ¹ is the number of carbon atoms. It represents an alkyl group of 1 to 20 or an aryl group having 6 to 20 carbon atoms, and R ² and R ³ are independently hydrogen atoms, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, respectively. R ⁴ and R ⁵ independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, m is an integer of 1 to 3, and l is 1 to 1. It is an integer of 20, and o is an integer of 1 to 20. ^{R 1 in} the case of a plurality of cases may be the same as or different from each other.

式中、Ｑ¹は、水素原子、並びにその一部分に分岐構造を有していてもよい、炭素数１〜２０のアルキル基及び炭素数６〜２０のアリール基からなる群より選ばれるいずれかを示し、Ｘ¹、Ｘ²、及びＸ³は、それぞれ独立して単結合、又は炭素原子、水素原子、窒素原子、硫黄原子、及び酸素原子からなる群より選ばれるいずれかを含有する有機基を示し、Ｙ¹、Ｙ²、及びＹ³は、それぞれ独立して炭素数１〜２０のアルキル基、炭素数１〜２０のアルコキシ基、及びハロゲン原子からなる群より選ばれるいずれかを示す。 In the modified conjugated diene polymer represented by the formulas (1) and / or the formula (2), (A / B / C) represents a block or random copolymer. The ratio of A, B, and C in the copolymer may be arbitrarily set, and the sequence may be random and is not particularly limited.

In the formula, Q ¹ is selected from the group consisting of an alkyl group having 1 to 20 carbon atoms and an aryl group having 6 to 20 carbon atoms, which may have a branched structure in a hydrogen atom and a part thereof. As shown, X ¹ , X ² , and X ³ each independently contain an organic group selected from the group consisting of a single bond or a carbon atom, a hydrogen atom, a nitrogen atom, a sulfur atom, and an oxygen atom. Shown, Y ¹ , Y ² , and Y ³ each independently represent one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom.

The modified conjugated diene polymer preferably contains a modified conjugated diene polymer represented by the formula (1). In that case, it is more preferable that C in the formula (1) represents the structural unit represented by the formula (3).

Conjugated diene compound (hereinafter, also referred to as "conjugated diene monomer") used for the conjugated diene polymer chain represented by A in the formulas (1) and (2) (hereinafter, also simply referred to as "conjugated diene polymer"). For example, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 1,3-heptadiene, 2-phenyl-1. , 3-butadiene, 3-methyl-1,3-pentadiene, and 2-chloro-1,3-butadiene. Among these, 1,3-butadiene, isoprene, and 2,3-dimethyl-1,3-butadiene are preferable.

Examples of the aromatic vinyl compound represented by B in the formulas (1) and (2) (hereinafter, also referred to as “aromatic vinyl monomer”) include styrene, 2-methylstyrene, 3-methylstyrene, and 4-methyl. Styrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, vinylethylbenzene, divinylbenzene, trivinylbenzene, divinyl Naphthalene, t-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl) dimethylaminoethyl ether, N, N-dimethylaminoethylstyrene, N, N-dimethylaminomethylstyrene, 2-ethylstyrene, 3-ethylstyrene , 4-Ethylstyrene, 2-t-butylstyrene, 3-t-butylstyrene, 4-t-butylstyrene, vinylxylene, vinylnaphthalene, vinylpyridine, diphenylethylene, and tertiary amino group-containing diphenylethylene (eg, 1- (4-N, N-dimethylaminophenyl) -1-phenylethylene, etc.) can be mentioned. Of these, styrene and α-methylstyrene are preferable.

When the conjugated diene polymer represented by A is a copolymer of a conjugated diene compound and an aromatic vinyl compound, the conjugated diene polymer has a high living property in anionic polymerization, and the conjugated diene polymer is 1,3-butadiene. It is preferably a copolymer containing styrene and styrene in the monomer composition. The copolymer preferably has a random copolymer moiety in which the distribution of the conjugated diene compound and the aromatic vinyl compound is irregular.

The modified conjugated diene polymer of the present embodiment has a weight of a conjugated diene monomer and a compound represented by the formula (3) or the formula (4) (hereinafter, also referred to as a "branching agent" or a "styrene derivative"). It may be a coalescence, or it may be a copolymer with a conjugated diene monomer, a branching agent and an aromatic vinyl compound. Further, as will be described later, hydrogenation may be performed by hydrogenating the conjugated diene portion of the conjugated diene-based polymer.

For example, when the conjugated diene monomer is butadiene or isoprene and this is polymerized with a branching agent containing an aromatic vinyl moiety, the polymerized chain is so-called polybutadiene or polyisoprene, and the branched portion contains a structure derived from aromatic vinyl. It becomes a polymer. By having such a structure, it is possible to improve the linearity of each polymer chain and the crosslink density after vulcanization, which has the effect of improving the abrasion resistance of the polymer. Therefore, it is suitable for applications such as tires, resin modification, automobile interior / exterior parts, anti-vibration rubber, and footwear.

When the conjugated diene-based polymer is used for a tread of a tire, a copolymer of a conjugated diene monomer, an aromatic vinyl monomer, and a branching agent is suitable, and the amount of the bonded conjugated diene in the copolymer for this application is 40 mass. It is preferably% or more and 100% by mass or less, and more preferably 55% by mass or more and 80% by mass or less.

The amount of bound aromatic vinyl in the modified conjugated diene polymer of the present embodiment is not particularly limited, but is preferably 0% by mass or more and 60% by mass or less, and 20% by mass or more and 45% by mass or less. Is more preferable.

When the amount of bonded conjugated diene and the amount of bonded aromatic vinyl are in the above ranges, they tend to be more excellent in processability, low hysteresis loss property and wet skid resistance balance, abrasion resistance, and fracture property when made into a vulcanized product. It is in. Here, the amount of bound aromatic vinyl can be measured by the ultraviolet absorption of the phenyl group, and the amount of bound conjugated diene can also be obtained from this. Specifically, the measurement can be performed according to the method described in Examples described later.

In the modified conjugated diene polymer of the present embodiment, the amount of vinyl bond in the conjugated diene bonding unit is not particularly limited, but is preferably 10 mol% or more and 75 mol% or less, and 20 mol% or more and 65 mol% or less. Is more preferable.

When the vinyl bond amount is in the above range, the vulcanized product tends to be more excellent in workability, low hysteresis loss property, and wear resistance. Here, when the modified diene polymer is a copolymer of butadiene and styrene, it is contained in the butadiene bond unit by the Hampton method (RR Hampton, Analytical Chemistry, 21,923 (1949)). The vinyl bond amount (1,2-bond amount) can be determined. Specifically, the measurement is performed by the method described in Examples described later.

Regarding the microstructure of the conjugated diene polymer of the present embodiment, the amount of each bond in the conjugated diene polymer is in the above range, and the glass transition temperature of the conjugated diene polymer is -80 ° C or higher to -15. When the temperature is in the range of ° C. or lower, a vulcanized product having excellent low hysteresis loss tends to be obtained. Regarding the glass transition temperature, according to ISO 22768: 2006, the DSC curve is recorded while raising the temperature in a predetermined temperature range, and the peak top (Inflection point) of the DSC differential curve is defined as the glass transition temperature. Specifically, the measurement is performed by the method described in Examples described later.

When the modified conjugated diene polymer of the present embodiment is a conjugated diene-aromatic vinyl copolymer, the number of blocks in which 30 or more aromatic vinyl units are linked may be small or absent. preferable. More specifically, when the modified conjugated diene polymer of the present embodiment is a butadiene-styrene copolymer, the method of Kolthoff (IM KOLTHOFF, et al., J. Polym. Sci. 1,429 ( In a known method of decomposing a polymer by the method described in 1946) and analyzing the amount of polystyrene insoluble in methanol, blocks in which 30 or more aromatic vinyl units are linked are the total amount of the modified conjugated diene polymer. On the other hand, it is preferably 5.0% by mass or less, more preferably 3.0% by mass or less.

When the modified conjugated diene polymer of the present embodiment is a conjugated diene-aromatic vinyl copolymer, it is preferable that the aromatic vinyl unit is present alone in a large proportion from the viewpoint of improving the low hysteresis loss performance.

Specifically, when the modified conjugated diene polymer of the present embodiment is a butadiene-styrene copolymer, the method by ozone decomposition known as the method of Tanaka et al. (Polymer, 22, 1721 (1981)) is used. When the modified conjugated diene polymer was decomposed and the styrene chain distribution was analyzed by GPC, the amount of isolated styrene was 40% by mass or more and the number of styrene chains was 8 or more with respect to the total amount of bonded styrene. The styrene structure is preferably 5.0% by mass or less. In this case, the obtained vulcanized rubber tends to have excellent performance with a particularly low hysteresis loss.

(Absolute molecular weight)
The absolute molecular weight is measured by a GPC-light scattering method with a viscosity detector. In general, a polymer having a branched structure tends to have a smaller molecular size when compared with a linear polymer having the same molecular weight. Therefore, the molecular weight of the polymer having a branched structure is determined by gel permeation chromatography (hereinafter, also referred to as “GPC”) measurement, which is a relative comparison method with a standard polystyrene sample, by sieving the polymer by the molecular size. Tends to be underestimated. Since the molecular size is directly observed by the light scattering method and the molecular weight (absolute molecular weight) is measured, it is not affected by the structure of the polymer or the interaction with the column packing material, and the branched structure of the conjugated diene polymer, etc. There is a tendency that the molecular weight can be measured accurately without being affected by the polymer structure of.

(Bifurcation degree (Bn))
From the viewpoint of processability, wear resistance, and fracture strength, the conjugated diene polymer of the present embodiment has a degree of branching (Bn) by a GPC-light scattering measurement method with a viscosity detector (hereinafter, simply referred to as a degree of branching (Bn)). Also referred to as) is preferably 3 or more.

The degree of branching (Bn) of 3 or more means that the modified conjugated diene polymer of the present embodiment has 5 or more side chain polymer chains with respect to the substantially longest polymer main chain. Means that.

The degree of branching (Bn) of the modified conjugated diene polymer is g'= 6Bn / {(Bn + 1) (Bn + 2) using a shrinkage factor (g') measured by the GPC-light scattering method with a viscosity detector. } Is defined.

In general, a polymer having a branch tends to have a smaller molecular size when compared with a linear polymer having the same absolute molecular weight.

The contraction factor (g') is an index of the ratio of the size occupied by the molecule to the linear polymer having the same absolute molecular weight. That is, as the degree of branching of the polymer increases, the shrinkage factor (g') tends to decrease.

In the present embodiment, the intrinsic viscosity is used as an index of the size of the molecule for this contractile factor, and the linear polymer follows the relational expression of ^{the intrinsic viscosity [η] = -3.883M 0.771.} In the above formula, M is an absolute molecular weight.

However, the contractile factor expresses the rate of decrease in the size of the molecule, and does not accurately represent the branched structure of the polymer.

Therefore, the degree of branching (Bn) of the conjugated diene polymer is calculated using the value of the shrinkage factor (g') at each absolute molecular weight of the modified conjugated diene polymer. The calculated "branch degree (Bn)" accurately represents the number of polymers directly or indirectly bonded to each other with respect to the longest main chain structure.

The calculated degree of bifurcation (Bn) serves as an index for expressing the bifurcation structure of the modified conjugated diene polymer. For example, in the case of a general 4-branched star-shaped polymer (4 polymer chains connected to the center), two polymer chain arms are bonded to the longest highly branched main chain structure. , The degree of branching (Bn) is evaluated as 2.

In the case of a general 8-branched star-shaped polymer, 6 arms of the polymer chain are bonded to the longest highly branched main chain structure, and the degree of branching (Bn) is evaluated as 6.

The modified conjugated diene polymer of the present embodiment has a branching degree (Bn) of 3 or more, but in such a case, the modified conjugated diene having a branch similar to that of a star-shaped polymer structure having 5 branches as a star-shaped polymer structure. It means that it is a system polymer.

Here, the "branch" is formed by directly or indirectly bonding one polymer with another polymer. Further, the "branch degree (Bn)" is the number of polymers directly or indirectly bonded to each other with respect to the longest main chain structure.

When the degree of branching (Bn) is 3 or more, the modified conjugated diene polymer of the present embodiment is extremely excellent in processability when it is made into a vulcanized product, and has abrasion resistance and abrasion resistance when it is made into a vulcanized product. Excellent breaking strength.

Generally, when the absolute molecular weight increases, the workability tends to deteriorate, and when the absolute molecular weight is increased in a linear polymer structure, the viscosity of the vulcanized product increases significantly, and the workability is significantly improved. Getting worse.

Therefore, even if a large number of functional groups are introduced into the polymer to improve the affinity and / or reactivity with silica blended as a filler, the silica is sufficiently dispersed in the polymer in the kneading step. I can't. As a result, the function of the introduced functional group is not exhibited, and the effect of improving the low hysteresis loss property by introducing the functional group, which should be originally expected, is not exhibited.

On the other hand, the modified conjugated diene polymer of the present embodiment is specified to have a branching degree (Bn) of 3 or more, so that the viscosity of the modified conjugated diene polymer increases significantly when it is made into a vulcanized product as the absolute molecular weight increases. Since it is suppressed, for example, it becomes sufficiently mixed with silica or the like in the kneading step, and silica can be dispersed around the conjugated diene polymer. As a result, for example, in a modified conjugated diene-based polymer, it is possible to improve wear resistance and fracture strength by setting a large molecular weight, and silica is dispersed around the polymer by sufficient kneading to form a functional group. It becomes possible to have a practically sufficient low hysteresis loss property by being able to act and / or react with the polymer.

The degree of branching (Bn) of the modified conjugated diene polymer of the present embodiment is 3 or more, preferably 4 or more, and more preferably 6 or more.
Modified conjugated diene-based polymers having a degree of branching (Bn) in this range tend to be excellent in processability when made into a vulcanized product.

The upper limit of the degree of branching (Bn) is not particularly limited and may be at least the detection limit, but is preferably 48 or less, more preferably 40 or less, and further preferably 32 or less. Even more preferably, it is 24 or less.
The modified conjugated diene polymer of the present embodiment tends to have excellent wear resistance when it is made into a vulcanized product because the degree of branching (Bn) is 48 or less.

From the viewpoint of processability, abrasion resistance, and low hysteresis loss, the conjugated diene polymer of the present embodiment has an absolute molecular weight (hereinafter, also simply referred to as "absolute molecular weight") by a GPC-light scattering measurement method with a viscosity detector. ) Is preferably 40 × 10 ⁴ or more and 500 × 10 ⁴ or less, more preferably 100 × 10 ⁴ or more and 300 × 10 ⁴ or less, and 150 × 10 ⁴ or more and 200 × 10 ⁴ or less. Is even more preferable.

The degree of branching and the absolute molecular weight of the modified conjugated diene polymer can be measured by the methods described in Examples described later.

The degree of branching and the absolute molecular weight of the modified conjugated diene polymer may be controlled by the amount of the branching agent added, or may be 3 or more depending on the combination of the amount of the branching agent added and the amount of the terminal coupling agent added. You may control it. Specifically, the degree of branching is controlled by the number of functional groups of the branching agent, the amount of the branching agent added, the timing of addition of the branching agent, the functional number of the coupling agent or the nitrogen atom-containing modifier, and the coupling. It can be controlled by the amount of the agent or the modifier containing a nitrogen atom added. More specifically, it will be described in the method for producing a modified conjugated diene polymer described later.

The modified conjugated diene polymer of the present embodiment has a number average molecular weight and a weight average molecular weight obtained as polystyrene-equivalent molecular weight by gel permeation chromatography (hereinafter, also referred to as “GPC”) measurement, which is a relative comparison method with a standard polystyrene sample. (Hereinafter, it is also simply referred to as "number average molecular weight" and "weight average molecular weight"). The number average molecular weight is preferably 5 × 10 ⁴ or more and 100 × 10 ⁴ or less, more preferably 10 × 10 ⁴ or more and 60 × 10 ⁴ or less, and 20 × 10 ⁴ or more and 50 × 10 ⁴ or less. Is even more preferable. The weight average molecular weight is preferably 10 × 10 ⁴ or more and 200 × 10 ⁴ or less, more preferably 20 × 10 ⁴ or more and 125 × 10 ⁴ or less, and 30 × 10 ⁴ or more and 75 × 10 ⁴ or less. Is even more preferable.

The number average molecular weight and the weight average molecular weight of the modified conjugated diene polymer can be measured by the methods described in Examples described later. The number average molecular weight and weight average molecular weight of the modified conjugated diene polymer should be controlled within the above ranges by, for example, controlling conditions such as temperature conditions in the polymerization step or adjusting the degree of branching in the branching step. Can be done. More specifically, it will be described in the method for producing a modified conjugated diene polymer described later.

The modified conjugated diene polymer of the present embodiment is determined to have Mooney viscosity and Mooney relaxation rate (hereinafter, also simply referred to as "Moony viscosity" and "Moony relaxation rate") by measurement using a Mooney viscometer. The Mooney viscosity is preferably 10 or more and 150 or less, more preferably 30 or more and 120 or less, and further preferably 50 or more and 100 or less. The Moony relaxation rate is preferably 0.10 or more and 1.00 or less, more preferably 0.25 or more and 0.80 or less, and further preferably 0.30 or more and 0.70 or less.

The Mooney viscosity and Mooney relaxation rate of the modified conjugated diene polymer can be measured by the methods described in Examples described later. The Mooney viscosity and Mooney relaxation rate of the modified conjugated diene polymer can be controlled within the above ranges by, for example, controlling conditions such as temperature conditions in the polymerization step or adjusting the degree of branching in the branching step. can. More specifically, it will be described in the method for producing a modified conjugated diene polymer described later.

In the present specification, the "modification rate" represents the mass ratio of the conjugated diene polymer having a nitrogen atom-containing functional group to the total amount of the conjugated diene polymer.

For example, when a nitrogen atom-containing modifier is reacted at the terminal end, the mass ratio of the conjugated diene polymer having a nitrogen atom-containing functional group by the nitrogen atom-containing modifier to the total amount of the conjugated diene polymer is modified. Expressed as a rate.

On the other hand, even when the polymer is branched by a branching agent containing a nitrogen atom, the produced conjugated diene-based polymer has a nitrogen atom-containing functional group, so that the branched polymer also has a modification rate. It will be counted at the time of calculation.

That is, in the present specification, the modified polymer by the modifying agent having a nitrogen atom-containing functional group and / or the branched polymer by the branching agent having a nitrogen atom-containing functional group, and the total mass ratio of these is determined. "Degeneration rate".

The conjugated diene-based polymer of the present embodiment has at least one end modified with a nitrogen atom-containing group, so that the composition can be processed into a composition containing a filler or the like, and the composition is a vulcanized product. There is a tendency for low hysteresis loss to improve while maintaining the wear resistance and fracture strength at the time.

The conjugated diene polymer of the present embodiment has a modification rate measured by the column adsorption GPC method with respect to the total amount of the conjugated diene polymer from the viewpoint of processability, abrasion resistance, and low hysteresis loss (hereinafter referred to as “)”. , Simply referred to as “modification rate”) is preferably 50% by mass or more.

The modification rate is preferably 55% by mass or more, more preferably 60% by mass or more, still more preferably 65% by mass or more, still more preferably 70% by mass or more. The upper limit of the modification rate is not particularly limited, but is, for example, 98% by mass.

The modification rate can be measured by chromatography capable of separating the functional group-containing modified component and the non-modified component.

As a method using this chromatography, a column for gel permeation chromatography using a polar substance such as silica that adsorbs a specific functional group as a filler is used, and the internal standard of the non-adsorbed component is quantified by comparison. A method (column adsorption GPC method) can be mentioned.

More specifically, the modification rate is the adsorption of a sample solution containing a sample and a low molecular weight internal standard polystyrene to a silica column from the difference between a chromatogram measured by a polystyrene gel column and a chromatogram measured by a silica column. Obtained by measuring the amount.
More specifically, the denaturation rate can be measured by the method described in Examples.

In the conjugated diene polymer of the present embodiment, the modification rate can be controlled by adjusting the addition amount of the modifier and the reaction method, whereby the modification rate can be controlled to 50% by mass or more.

For example, a method of polymerizing using an organic lithium compound having at least one nitrogen atom in the molecule described later as a polymerization initiator, a method of copolymerizing a monomer having at least one nitrogen atom in the molecule, which will be described later. The above modification rate can be obtained by combining methods using a modifier having a structural formula and controlling the polymerization conditions.

The conjugated diene polymer of the present embodiment is a conjugated diene polymer having a star-shaped polymer structure having three or more branches from the viewpoint of the balance between processability and abrasion resistance, and has at least one star-shaped structure. The branched chain of the above has a portion derived from a vinyl-based monomer containing an alkoxysilyl group or a halosilyl group, and a portion derived from the vinyl-based monomer containing the alkoxysilyl group or the halosilyl group has a further branched structure. It is preferable that it is a conjugated diene-based polymer having.

The branched structure has two or more branch points at a branch point derived from a vinyl-based monomer containing an alkoxysilyl group or a halosilyl group, preferably three or more branch points, and preferably four or more branch points. More preferred.

Further, the branch point forming the branched structure preferably has at least two or more polymer chains, more preferably has three or more polymer chains that are not the main chain, and more preferably the main chain. It has four or more polymer chains that are not chains.

In particular, in a branched structure composed of a vinyl monomer containing an alkoxysilyl group or a halosilyl group, when ^{signal detection is performed by 29} Si-NMR, the range is in the range of -45 ppm to -65 ppm, and more specifically, -50 ppm to -60 ppm. A peak derived from the branched structure is detected in the range of.

式中、Ｒ¹及びＲ²は、それぞれ独立して炭素数１〜２０のヒドロカルビル基を示し、Ｒ³は、炭素数１〜２０のアルカンジイル基を示し、Ｒ⁴及びＲ⁵は、それぞれ独立して水素原子、炭素数１〜２０のアルキル基、又は炭素数６〜２０のアリール基を示し、ｎは、１〜３の整数である。複数のＲ¹及びＲ²のいずれかは、それらが互いに同一でも異なっていてもよい。 [Method for producing modified conjugated diene polymer]
In the method for producing a modified conjugated diene polymer of the present embodiment, an alkali metal compound or an alkaline earth metal compound is used as a polymerization initiator, and the conjugated diene compound, or the conjugated diene compound and the aromatic vinyl compound are polymerized or copolymerized. A polymerization step of obtaining a conjugated diene polymer having an active terminal, a branching step of reacting a styrene derivative with the active terminal of the obtained conjugated diene polymer to introduce a branched structure, and a branching step. The subsequent active terminal has a modification step of reacting the compound represented by the following formula (A).

In the formula, R ¹ and R ² independently represent a hydrocarbyl group having 1 to 20 carbon atoms, R ³ represents an alkanediyl group having 1 to 20 carbon atoms, and R ⁴ and R ⁵ are independent of each other. It represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and n is an integer of 1 to 3 carbon atoms. The plurality of R ¹ and R ² may be the same or different from each other.

The conjugated diene-based polymer constituting the modified conjugated diene-based polymer is a homopolymer of a single conjugated diene compound, a copolymer of different types of conjugated diene compounds, and a common weight of the conjugated diene compound and an aromatic vinyl compound. It may be any of coalescence.
According to the present embodiment, by introducing a branch point into the main chain, a modified conjugated diene polymer having a higher degree of branching than when a branched structure is introduced into the conjugated diene polymer using only a modifier can be obtained. It is possible to provide a polymer design method having a high degree of freedom in polymer design, which can be produced and the lengths of the main chain and side chains can be adjusted, thereby producing a modified conjugated diene polymer exhibiting excellent processability and abrasion resistance. Can be provided.

(Polymerization process)
In the polymerization step in the method for producing a modified conjugated diene polymer of the present embodiment, an alkali metal compound or an alkaline earth metal compound is used as a polymerization initiator, and the conjugated diene compound or the conjugated diene compound and an aromatic vinyl compound are polymerized. Alternatively, by copolymerizing, a conjugated diene-based polymer having an active terminal is obtained.
In the polymerization step, it is preferable to carry out polymerization by a growth reaction by a living anionic polymerization reaction, whereby a conjugated diene-based polymer having an active terminal can be obtained.

<Polymerization initiator>
As the polymerization initiator, it is preferable to use an organic lithium-based compound, and it is more preferable to use an organic monolithium compound.
The organic monolithium compound is not particularly limited, and examples thereof include a small molecule compound and an organic monolithium compound which is a solubilized oligomer.
Further, as the organic monolithium compound, for example, a compound having a carbon-lithium bond, a compound having a nitrogen-lithium bond, and a compound having a tin-lithium bond shall be used in the bonding mode of the organic group and the lithium thereof. Can be done.

The amount of the organic monolithium compound used as the polymerization initiator is preferably determined by the molecular weight of the target conjugated diene polymer.
The amount of a monomer such as a conjugated diene compound used relative to the amount of the polymerization initiator used is related to the degree of polymerization of the target conjugated diene polymer. That is, it tends to be related to the number average molecular weight and / or the weight average molecular weight.
Therefore, in order to increase the molecular weight of the conjugated diene-based polymer, it is preferable to adjust in the direction of decreasing the polymerization initiator, and in order to decrease the molecular weight, it is preferable to adjust in the direction of increasing the amount of the polymerization initiator.

The substituted amino group is an amino group having a structure that does not have active hydrogen or protects active hydrogen.
The alkyllithium compound having an amino group having no active hydrogen is not particularly limited, and is, for example, 3-dimethylaminopropyl lithium, 3-diethylaminopropyl lithium, 4- (methylpropylamino) butyl lithium, and 4-hexamethylene. Examples include iminobutyllithium.
The alkyllithium compound having an amino group having a structure in which active hydrogen is protected is not particularly limited, and examples thereof include 3-bistrimethylsilylaminopropyllithium and 4-trimethylsilylmethylaminobutyllithium.

The dialkylaminolithium is not particularly limited, and is, for example, lithium dimethylamide, lithium diethylamide, lithium dipropylamide, lithium dibutylamide, lithium di-n-hexylamide, lithium diheptylamide, lithium diisopropylamide, lithium dioctylamide, lithium-. Di-2-ethylhexylamide, lithium didecylamide, lithium ethylpropylamide, lithium ethylbutylamide, lithium ethylbenzylamide, lithium methylphenethylamide, lithium hexamethyleneimide, lithium pyrrolidide, lithium piperidide, lithium heptamethylene Imid, lithium morpholide, 1-lithioazacyclooctane, 6-lithio-1,3,3-trimethyl-6-azabicyclo [3.2.1] octane, and 1-lithio-1,2,3,6 -Tetrahydropyridine can be mentioned.

These organic monolithium compounds having a substituted amino group were solubilized in normal hexane and cyclohexane by reacting a small amount of polymerizable monomers such as 1,3-butadiene, isoprene, and styrene. It can also be used as an organic monolithium compound of an oligomer.

The organic monolithium compound is preferably an alkyllithium compound from the viewpoint of easy industrial availability and easy control of the polymerization reaction. In this case, a conjugated diene-based polymer having an alkyl group at the polymerization initiation terminal can be obtained.
The alkyllithium compound is not particularly limited, and examples thereof include n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, benzyllithium, phenyllithium, and stillbenlithium.
As the alkyllithium compound, n-butyllithium and sec-butyllithium are preferable from the viewpoint of easy industrial availability and easy control of the polymerization reaction.

These organic monolithium compounds may be used alone or in combination of two or more. In addition, it may be used in combination with other organometallic compounds. Examples of other organometallic compounds include alkaline earth metal compounds, other alkali metal compounds, and other organometallic compounds.
The alkaline earth metal compound is not particularly limited, and examples thereof include an organic magnesium compound, an organic calcium compound, and an organic strontium compound. Also included are compounds of alkaline earth metals alcoxide, sulfonate, carbonate, and amide.
Examples of the organic magnesium compound include dibutyl magnesium and ethyl butyl magnesium.
Examples of other organometallic compounds include organoaluminum compounds.

In the polymerization step, the polymerization reaction mode is not particularly limited, and examples thereof include a batch type (also referred to as “batch type”) and a continuous type polymerization reaction mode.
In the continuous equation, one or two or more connected reactors can be used. As the continuous reactor, for example, a tank type or tube type reactor with a stirrer is used. In the continuous equation, preferably, the monomer, the inert solvent, and the polymerization initiator are continuously fed to the reactor to obtain a polymer solution containing the polymer in the reactor, which is continuously weighted. The coalesced solution is drained.
As the batch reactor, for example, a tank type reactor with a stirrer is used. In the batch formula, preferably, the monomer, inert solvent, and polymerization initiator are fed, and if necessary, the monomer is added continuously or intermittently during the polymerization, and the polymer is added in the reactor. A polymer solution containing the mixture is obtained, and the polymer solution is discharged after the completion of the polymerization.
In the method for producing a modified conjugated diene polymer of the present embodiment, in order to obtain a conjugated diene polymer having an active terminal at a high ratio in the polymerization step, the polymer is continuously discharged, and the next step is performed in a short time. A continuous type that can be subjected to the reaction of the above is preferable. In the continuous system, the number of reactors is not particularly limited, and one or two or more connected reactors can be used. The reactor is preferably one in which the monomer and the polymerization initiator are sufficiently brought into contact with each other in the solution, and a tank type or tube type with a stirrer is used. The number of reactors can be appropriately selected, but one reactor is preferable from the viewpoint of saving space in the manufacturing equipment, and two or more are preferable from the viewpoint of improving productivity. When two or more reactors are used, it is more preferable to add the branching agent to the second and subsequent reactors.

The polymerization step of the conjugated diene polymer is preferably carried out in an inert solvent.
Examples of the inert solvent include hydrocarbon-based solvents such as saturated hydrocarbons and aromatic hydrocarbons. Specific hydrocarbon solvents are not particularly limited, but are, for example, aliphatic hydrocarbons such as butane, pentane, hexane and heptane; and alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane and methylcyclohexane; Examples thereof include aromatic hydrocarbons such as benzene, toluene and xylene, and hydrocarbons composed of mixtures thereof.
By treating impurities such as allenes and acetylenes with an organometallic compound before subjecting them to a polymerization reaction, a conjugated diene-based polymer having a high concentration of active terminals tends to be obtained, and modification with a high modification rate. It is preferable because a conjugated diene-based polymer tends to be obtained.

In the polymerization step, a polar compound may be added. As a result, the aromatic vinyl compound can be copolymerized with the conjugated diene compound at random, and the polar compound tends to function as a vinylizing agent for controlling the microstructure of the conjugated diene portion. It also tends to be effective in promoting the polymerization reaction.

The polar compound is not particularly limited, but for example, tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, 2,2-bis (2-oxolanyl) propane and the like. Ethers; tertiary amine compounds such as tetramethylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine, quinuclidine; potassium-tert-amylate, potassium-tert-butyrate, sodium-tert-butyrate, sodium amylate Alkoxide compounds such as, etc .; phosphine compounds such as triphenylphosphine and the like can be used.
These polar compounds may be used alone or in combination of two or more.

The amount of the polar compound used is not particularly limited and can be selected depending on the intended purpose and the like, but it is preferably 0.01 mol or more and 100 mol or less with respect to 1 mol of the polymerization initiator.
Such a polar compound (vinyl agent) can be used in an appropriate amount as an agent for adjusting the microstructure of the conjugated diene portion of the conjugated diene polymer, depending on the desired amount of vinyl bond.
Many polar compounds have a randomizing effect that is effective in the copolymerization of conjugated diene compounds and aromatic vinyl compounds at the same time, and tend to be used as an agent for adjusting the distribution of aromatic vinyl compounds and adjusting the amount of styrene block. It is in.
As a method for randomizing the conjugated diene compound and the aromatic vinyl compound, for example, as described in JP-A-59-140211, the total amount of styrene and a part of 1,3-butadiene are copolymerized. A method of initiating the polymerization reaction and intermittently adding the remaining 1,3-butadiene during the copolymerization reaction may be used.

The polymerization temperature in the polymerization step is preferably a temperature at which living anionic polymerization proceeds, and more preferably 0 ° C. or higher and 120 ° C. or lower from the viewpoint of productivity.
Within such a range, the amount of reaction of the denaturant to the active terminal after the completion of polymerization tends to be sufficiently secured. Even more preferably, it is 50 ° C. or higher and 100 ° C. or lower.

(Branching process)
The branching step of the present embodiment is a step of reacting a styrene derivative with the active terminal of the conjugated diene polymer to introduce a branched structure. The styrene derivative, which is a branching agent used there, has a main skeleton in which only one active terminal remains at the branching site after the branching reaction from the viewpoint of polymerization continuity and prevention of gelation. It is preferable that the styrene derivative has a reactivity that sufficiently reacts with the polymerization active terminal during the partial branching reaction.
That is, when the styrene derivative is polymerized as styrene, the styrene derivative is incorporated into the main chain while maintaining the polymerization activity, and another monomer is polymerized at the terminal where the activity is maintained, so that the polymer chain is further extended. Further, the active end of another polymer chain reacts with the functional group of the incorporated styrene derivative to form a bond, whereby a branched structure is formed. By repeating this reaction, the number of branches of the polymer chain increases, the polymer structure becomes more complicated, and the molecular weight becomes larger.

From the viewpoint of polymerization continuity and controllability of the polymer structure, it is also necessary that the functional group desorbed after reacting with the active end of another polymer chain has a small effect of inhibiting polymerization. Here, "there is little polymerization inhibitory effect" means that there are few side reactions of anionic polymerization, such as chain transfer reaction, inactivation during polymerization, and decrease in activity due to an increase in the degree of association of the polymer.
The functional group of the styrene derivative needs to be one that does not excessively improve the polymerization activity, and further needs to be one that does not inactivate the polymerization activity. When polymerizing a polymer by living anionic polymerization, it is important that it does not have a hydrogen atom as a functional group that does not inactivate the active end, and that it is a hard base as defined by Pearson's HASB law. Specific examples thereof include an alkoxy group and a halogen group. From these, the structure of the styrene derivative as the branching agent used in the production method of the present embodiment can be selected from the viewpoint of reactivity with the active terminal and that the desorbed functional group does not inhibit the polymerization. can.
More specifically, using a styrene derivative represented by the following formula (3) having a styrene skeleton as the main skeleton or the formula (4) having a diphenylethylene skeleton as the main skeleton suppresses the chain transfer reaction and activates the terminal. It is preferable from the viewpoint of suppressing deactivation and preventing gelation.

式中、Ｑ¹は、水素原子、並びにその一部分に分岐構造を有していてもよい、炭素数１〜２０のアルキル基及び炭素数６〜２０のアリール基からなる群より選ばれるいずれかを示し、Ｘ¹、Ｘ²、及びＸ³は、それぞれ独立して単結合、又は炭素原子、水素原子、窒素原子、硫黄原子、及び酸素原子からなる群より選ばれるいずれかを含有する有機基を示し、Ｙ¹、Ｙ²、及びＹ³は、それぞれ独立して炭素数１〜２０のアルキル基、炭素数１〜２０のアルコキシ基、及びハロゲン原子からなる群より選ばれるいずれかを示す。

In the formula, Q ¹ is selected from the group consisting of an alkyl group having 1 to 20 carbon atoms and an aryl group having 6 to 20 carbon atoms, which may have a branched structure in a hydrogen atom and a part thereof. As shown, X ¹ , X ² , and X ³ each independently contain an organic group selected from the group consisting of a single bond or a carbon atom, a hydrogen atom, a nitrogen atom, a sulfur atom, and an oxygen atom. Shown, Y ¹ , Y ² , and Y ³ each independently represent one selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom.

The styrene derivative which is a branching agent used in the branching step preferably contains a compound represented by the formula (3) from the viewpoint of improving the degree of branching of polymerization. Further, in the formula (3), it is more preferable that ^{Q 1 represents a hydrogen atom.}

Further, in the present embodiment, the styrene derivative which is a branching agent used in the branching step contains a compound represented by the formula (3) from the viewpoint of continuity of polymerization and improvement of the degree of branching, and is of the formula. In (3), ^{it is more preferable that Q 1} represents a hydrogen atom and Y ¹ represents an alkoxy group or a halogen atom having 1 to 20 carbon atoms.

Further, in the present embodiment, the styrene derivative which is a branching agent used in the branching step contains a compound represented by the formula (4) from the viewpoint of continuity of polymerization and improvement of the degree of branching, and is of the formula. In (4), ^{it is more preferable that Y 2} represents an alkoxy group or a halogen atom having 1 to 20 carbon atoms, and Y ³ represents an alkoxy group or a halogen atom having 1 to 20 carbon atoms.

Further, in the present embodiment, the styrene derivative which is a branching agent used in the branching step is a compound represented by the formula (3) from the viewpoint of continuity of polymerization, improvement of branching degree and improvement of modification rate. In the formula (3), Q ¹ represents a hydrogen atom, and Y ¹ more preferably represents an alkoxy group having 1 to 20 carbon atoms.

Further, in the present embodiment, the styrene derivative which is a branching agent used in the branching step is represented by the formula (3) from the viewpoint of continuity of polymerization, improvement of branching degree, and further improvement of modification rate. In the formula (3), Q ¹ represents a hydrogen atom, X ¹ represents a single bond, and Y 1 represents an alkoxy group having 1 to 20 carbon atoms.

Further, in the present embodiment, the styrene derivative which is a branching agent used in the branching step is represented by the formula (4) from the viewpoint of continuity of polymerization, improvement of branching degree, and further improvement of modification rate. In formula (4), X ² represents a single bond, Y ² represents an alkoxy group or a halogen atom having 1 to 20 carbon atoms, X ³ represents a single bond, and Y ³ Is more preferably exhibited as an alkoxy group or a halogen atom having 1 to 20 carbon atoms.

The styrene derivative represented by the formula (3) is not particularly limited, but is, for example, trimethoxy (4-vinylphenyl) silane, triethoxy (4-vinylphenyl) silane, tripropoxy (4-vinylphenyl) silane, tributoxy ( 4-Vinylphenyl) silane, triisopropoxy (4-vinylphenyl) silane, trimethoxy (3-vinylphenyl) silane, triethoxy (3-vinylphenyl) silane, tripropoxy (3-vinylphenyl) silane, tributoxy (3-) Vinylphenyl) silane, triisopropoxy (3-vinylphenyl) silane, trimethoxy (2-vinylphenyl) silane, triethoxy (2-vinylphenyl) silane, tripropoxy (2-vinylphenyl) silane, tributoxy (2-vinylphenyl) ) Silane, triisopropoxy (2-vinylphenyl) silane, dimethoxymethyl (4-vinylphenyl) silane, diethoxymethyl (4-vinylphenyl) silane, dipropoxymethyl (4-vinylphenyl) silane, dibutoxymethyl ( 4-Vinylphenyl) silane, diisopropoxymethyl (4-vinylphenyl) silane, dimethoxymethyl (3-vinylphenyl) silane, diethoxymethyl (3-vinylphenyl) silane, dipropoxymethyl (3-vinylphenyl) silane , Dibutoxymethyl (3-vinylphenyl) silane, diisopropoxymethyl (3-vinylphenyl) silane, dimethoxymethyl (2-vinylphenyl) silane, diethoxymethyl (2-vinylphenyl) silane, dipropoxymethyl (2) -Vinylphenyl) silane, dibutoxymethyl (2-vinylphenyl) silane, diisopropoxymethyl (2-vinylphenyl) silane, dimethylmethoxy (4-vinylphenyl) silane, dimethylethoxy (4-vinylphenyl) silane, dimethyl Propoxy (4-vinylphenyl) silane, dimethylbutoxy (4-vinylphenyl) silane, dimethylisopropoxy (4-vinylphenyl) silane, dimethylmethoxy (3-vinylphenyl) silane, dimethylethoxy (3-vinylphenyl) silane, Dimethylpropoxy (3-vinylphenyl) silane, dimethylbutoxy (3-vinylphenyl) silane, dimethylisopropoxy (3-vinylphenyl) silane, dimethylmethoxy (2-vinylphenyl) silane, dimethylethoxy (2-vinylphenyl) Si Orchid, dimethylpropoxy (2-vinylphenyl) silane, dimethylbutoxy (2-vinylphenyl) silane, dimethylisopropoxy (2-vinylphenyl) silane, trimethoxy (4-isopropenylphenyl) silane, triethoxy (4-isopropenylphenyl) ) Silane, tripropoxy (4-isopropenylphenyl) silane, tributoxy (4-isopropenylphenyl) silane, triisopropoxy (4-isopropenylphenyl) silane, trimethoxy (3-isopropenylphenyl) silane, triethoxy (3-isopropenylphenyl) silane Isopropenylphenyl) silane, tripropoxy (3-isopropenylphenyl) silane, tributoxy (3-isopropenylphenyl) silane, triisopropoxy (3-isopropenylphenyl) silane, trimethoxy (2-isopropenylphenyl) silane, triethoxy (2-Isopropenylphenyl) silane, tripropoxy (2-isopropenylphenyl) silane, tributoxy (2-isopropenylphenyl) silane, triisopropoxy (2-isopropenylphenyl) silane, dimethoxymethyl (4-isopropenylphenyl) ) Silane, diethoxymethyl (4-isopropenylphenyl) silane, dipropoxymethyl (4-isopropenylphenyl) silane, dibutoxymethyl (4-isopropenylphenyl) silane, diisopropoxymethyl (4-isopropenylphenyl) Silane, dimethoxymethyl (3-isopropenylphenyl) silane, diethoxymethyl (3-isopropenylphenyl) silane, dipropoxymethyl (3-isopropenylphenyl) silane, dibutoxymethyl (3-isopropenylphenyl) silane, di Isopropoxymethyl (3-isopropenylphenyl) silane, dimethoxymethyl (2-isopropenylphenyl) silane, diethoxymethyl (2-isopropenylphenyl) silane, dipropoxymethyl (2-isopropenylphenyl) silane, dibutoxymethyl (2-Isopropenylphenyl) silane, diisopropoxymethyl (2-isopropenylphenyl) silane, dimethylmethoxy (4-isopropenylphenyl) silane, dimethylethoxy (4-isopropenylphenyl) silane, dimethylpropoxy (4-isopro) Penylphenyl) silane, dimethylbutoxy (4-isopropenylphenyl) silane, dimethylisopropoxy (4-Isopropenylphenyl) silane, dimethylmethoxy (3-isopropenylphenyl) silane, dimethylethoxy (3-isopropenylphenyl) silane, dimethylpropoxy (3-isopropenylphenyl) silane, dimethylbutoxy (3-isopropenylphenyl) ) Silane, dimethylisopropoxy (3-isopropenylphenyl) silane, dimethylmethoxy (2-isopropenylphenyl) silane, dimethylethoxy (2-isopropenylphenyl) silane, dimethylpropoxy (2-isopropenylphenyl) silane, dimethylbutoxy (2-Isopropenylphenyl) silane, dimethylisopropoxy (2-isopropenylphenyl) silane, trichloro (4-vinylphenyl) silane, trichloro (3-vinylphenyl) silane, trichloro (2-vinylphenyl) silane, tribromo ( 4-Vinylphenyl) silane, tribromo (3-vinylphenyl) silane, tribromo (2-vinylphenyl) silane, dichloromethyl (4-vinylphenyl) silane, dichloromethyl (3-vinylphenyl) silane, dichloromethyl (2-) Vinylphenyl) silane, dibromomethyl (4-vinylphenyl) silane, dibromomethyl (3-vinylphenyl) silane, dibromomethyl (2-vinylphenyl) silane, dimethylchloro (4-vinylphenyl) silane, dimethylchloro (3-) Vinylphenyl) silane, dimethylchloro (2-vinylphenyl) silane, dimethylbromo (4-vinylphenyl) silane, dimethylbromo (3-vinylphenyl) silane, dimethylbromo (2-vinylphenyl) silane, trimethoxy (4-vinyl) Examples thereof include benzyl) silane, triethoxy (4-vinylbenzyl) silane, and tripropoxy (4-vinylbenzyl) silane.
Among these, trimethoxy (4-vinylphenyl) silane, triethoxy (4-vinylphenyl) silane, tripropoxy (4-vinylphenyl) silane, tributoxy (4-vinylphenyl) silane triisopropoxy (4-vinylphenyl) Silane, Trimethoxy (3-vinylphenyl) silane, Triethoxy (3-vinylphenyl) silane, Tripropoxy (3-vinylphenyl) silane, Tributoxy (3-vinylphenyl) silane, Triisopropoxy (3-vinylphenyl) silane, And trichloro (4-vinylphenyl) silane are preferred, trimethoxy (4-vinylphenyl) silane, triethoxy (4-vinylphenyl) silane, tripropoxy (4-vinylphenyl) silane, tributoxy (4-vinylphenyl) silane triiso Propoxy (4-vinylphenyl) silane, trimethoxy (4-vinylbenzyl) silane, and triethoxy (4-vinylbenzyl) silane are more preferred, with trimethoxy (4-vinylphenyl) silane and triethoxy (4-vinylphenyl) silane. More preferred.

The styrene derivative represented by the formula (4) is not particularly limited, but for example, 1-bis (4-trimethoxysilylphenyl) ethylene, 1,1-bis (4-triethoxysilylphenyl) ethylene, 1, 1-bis (4-tripropoxycysilylphenyl) ethylene, 1,1-bis (4-tripentoxysilylphenyl) ethylene, 1,1-bis (4-triisopropoxysilylphenyl) ethylene, 1,1- Bis (3-trimethoxysilylphenyl) ethylene, 1,1-bis (3-triethoxysilylphenyl) ethylene, 1,1-bis (3-tripropoxycysilylphenyl) ethylene, 1,1-bis (3-) Trypentoxysilylphenyl) ethylene, 1,1-bis (3-triisopropoxysilylphenyl) ethylene, 1,1-bis (2-trimethoxysilylphenyl) ethylene, 1,1-bis (2-triethoxysilylphenyl) ethylene, 1,1-bis (2-triethoxysilylphenyl) ethylene Phenyl) ethylene, 1,1-bis (3-tripropoxycysilylphenyl) ethylene, 1,1-bis (2-tripentoxysilylphenyl) ethylene, 1,1-bis (2-triisopropoxysilylphenyl) Ethylene, 1,1-bis (4- (dimethylmethoxysilyl) phenyl) ethylene, 1,1-bis (4- (diethylmethoxysilyl) phenyl) ethylene, 1,1-bis (4- (dipropylmethoxysilyl)) Phenyl) ethylene, 1,1-bis (4- (dimethylethoxysilyl) phenyl) ethylene, 1,1-bis (4- (diethylethoxysilyl) phenyl) ethylene, 1,1-bis (4- (dipropylethoxy) ethoxy) Cyril) phenyl) ethylene, 1,1-bis (4-trimethoxysilylbenzyl) ethylene, 1,1-bis (4-triethoxysilylbenzyl) ethylene, 1,1-bis (4-tripropoxycysilylbenzyl) Examples include ethylene and 1,1-bis (4-tripentoxysilylbenzyl) ethylene.
Among these, 1,1-bis (4-trimethoxysilylphenyl) ethylene, 1,1-bis (4-triethoxysilylphenyl) ethylene, 1,1-bis (4-tripropoxycysilylphenyl) ethylene , 1,1-bis (4-tripentoxysilylphenyl) ethylene, and 1,1-bis (4-triisopropoxysilylphenyl) ethylene are preferred, and 1,1-bis (4-trimethoxysilylphenyl) ethylene. Is more preferable.
By using the styrene derivatives represented by the formulas (3) and (4), the number of branches is improved, and the effects of improving wear resistance and workability can be obtained.

In the method for producing a modified conjugated diene polymer of the present embodiment, the timing of adding the branching agent is particularly long as the polymerization step in which the conjugated diene polymer having an active terminal is present in the reaction system is ongoing. It is not limited and can be selected according to the purpose and the like, but from the viewpoint of improving the absolute molecular weight of the conjugated diene polymer and improving the coupling rate, the raw material conversion rate is 20% or more after the addition of the polymerization initiator. The timing is preferably 40% or more, more preferably 50% or more, even more preferably 65% or more, and even more preferably 75% or more.

Further, during or after the branching step, a monomer which is a desired raw material may be further added to continue the polymerization step after the branching, or these may be repeated.

The monomer to be added is not particularly limited, but is preferably a conjugated diene compound and / or an aromatic vinyl compound, and particularly when the monomer is added during the branching step, at the branching point of the conjugated diene-based polymer. From the viewpoint of improving the modification rate by alleviating the steric damage, the total amount of conjugated diene-based monomers used in the polymerization step, for example, 5% or more, more preferably 10% or more, more preferably 15% or more of the total amount of butadiene. % Or more, more preferably 20% or more, and even more preferably 25% or more and 30% or less. In such a case, in particular, using a continuous polymerization process, adding the monomer in the total amount of conjugated diene-based monomers used in the polymerization step, for example, 5% or more of the total amount of butadiene during the branching step improves the modification rate. Preferred from the point of view.

When the amount of the monomer to be added is within the above range, the molecular weight between the branching point by the branching agent and the branching point by the modifying agent becomes long, and it tends to be easy to obtain a highly linear molecular structure. By adopting a highly linear molecular structure, the entanglement of the molecular chains of the conjugated diene polymer increases when it is made into a vulcanized product, and a rubber composition having excellent wear resistance, steering stability and fracture strength can be obtained. It tends to be easy to obtain.

Since the length of the main chain and the side chain can be adjusted by the timing of adding the branching agent and the amount of the monomer to be added, the degree of freedom in polymer design is high.

The branched structure of the conjugated diene polymer into which the branched structure is introduced, which is obtained in the branching step in the method for producing the modified conjugated diene polymer of the present embodiment, is preferably 3 branches or more and 24 branches or less, more preferably. It is preferably 4 branches or more and 20 branches or less, and more preferably 5 branches or more and 18 branches or less.

By setting the number of branches to 24 or less, it tends to be easy to react with a modifying agent having a functional group to form a modified conjugated diene polymer in the modification step described later, or to further extend the polymer chain by a coupling reaction. There is a tendency that the obtained polymer has excellent processability when the number of branches is 3 or more.

An appropriate amount of the branching agent can be used as a branching point of the branched structure of the conjugated diene portion of the conjugated diene-based polymer, depending on the desired number of branching points.

The amount of the branching agent added is not particularly limited, and the amount added can be selected according to the purpose and the like, but the end-termination reaction rate of the conjugated diene polymer is improved, the coupling rate is improved, and after branching. From the viewpoint of polymerization continuity, the molar ratio of the branching agent to the amount of the active polymerization initiator is preferably 1/2 or less, preferably 1/100 or more, and 1/3 or less. It is more preferably 1/50 or more, further preferably 1/4 or less and 1/30 or more, and even more preferably 1/6 or less and 1/25 or more. , One-eighth or less, and more preferably one-twelfth or more.

The amount of the branching agent added in the branching step of forming the branched structure is not particularly limited and can be selected according to the purpose and the like, but is 0 mol or more per 1 mol of the polymerization initiator. It is preferably 5 mol or less, more preferably 0.001 mol or more and 0.4 mol or less, and further preferably 0.005 mol or more and 0.25 mol or less.

Further, during and / or after the branching step, the monomer may be further added to continue the polymerization step after the branching, and after the addition of the monomer, a branching agent is further added and the monomer is added. It may be repeated.

By adding the monomer, the effect of improving the continuity of polymerization and improving the coupling rate and the modification rate can be obtained by alleviating the steric hindrance around the branch point. This makes it possible to form a branch at a desired position while increasing the molecular weight of the polymer.

The monomer to be added may be an aromatic vinyl such as styrene or a conjugated diene compound such as butadiene, or a mixture thereof, which may be the same as or different from the type and ratio of the monomer to be polymerized first, but for the continuity of polymerization. From the viewpoint, a conjugated diene compound is preferable. From the viewpoint of improving the heat resistance of the polymer, it is preferable to add an aromatic vinyl compound.

Further, as described above, the monomer may be further added during and / or after the branching step to continue the polymerization step after the branching, and the branching agent is further added after the addition of the monomer. , Monomer may be added and repeated.

By adding the monomer, the effect of improving the continuity of polymerization and the modification rate and the modification rate can be obtained by alleviating the steric hindrance around the branch point. This makes it possible to form a branch at a desired position while increasing the molecular weight of the polymer.

The monomer to be added may be an aromatic vinyl such as styrene, a conjugated diene compound such as butadiene, or a mixture thereof, and may be the same as or different from the type and ratio of the monomer to be polymerized first, but from the viewpoint of continuity of polymerization. Is preferably a conjugated diene compound. From the viewpoint of improving the heat resistance of the polymer, it is preferable to add an aromatic vinyl compound.

In the case of producing a modified conjugated diene polymer, in order for the absolute molecular weight range to reach 100,000 or more and 1,000,000 or less, the amount of the branching agent added must be one-third or less in terms of molar ratio with respect to the polymerization initiator. By controlling in the range of 1/50 or more, it is preferable to make the number of functional groups of the modifier bifunctional or higher while preventing the polymerization initiator from being completely consumed before the modification step while forming branches. In order to reach the range of weight average molecular weight of 200,000 or more and 900,000 or less, the amount of the branching agent added is controlled in the range of 1/3 or less and 1/50 or more in terms of molar ratio with respect to the polymerization initiator. It can be achieved by doing.

(Degeneration process)
In the method for producing a modified conjugated diene polymer of the present embodiment, a primary or secondary amine is formed on the active terminal of the conjugated diene polymer obtained through the above-mentioned polymerization step and branching step. Reacting a denaturing amine with a denaturing agent in the molecule is called a denaturing step. Other denaturing agents or coupling agents may be used in addition to the above-mentioned denaturing agents. The other modifier or coupling agent is not particularly limited as long as it is a compound capable of reacting with the active terminal of the conjugated diene polymer obtained by the above-mentioned polymerization step and branching step, and the modifier of the conjugated diene polymer. Alternatively, a known compound can be used as the coupling agent.

When other denaturing agents or coupling agents are used, the ratio of their use is preferably 10 mol% or less, and more preferably 5 mol% or less.
By the modification step, a modified conjugated diene-based polymer having a large number of branched polymer chains and modified with a group that interacts with silica can be obtained.

As a modifier having a protected amine capable of forming a primary or secondary amine, a compound having an unsaturated bond and a protected amine in the molecule is not limited to the following, but for example, 4, 4'-vinylidenebis [N, N-bis (trimethylsilyl) aniline], 4,4'-vinylidenebis [N, N-bis (triethylsilyl) aniline], 4,4'-vinylidenebis [N, N-bis] (T-butyldimethylsilyl) aniline], 4,4'-vinylidenebis [N-methyl-N- (trimethylsilyl) aniline], 4,4'-vinylidenebis [N-ethyl-N- (trimethylsilyl) aniline], 4,4'-vinylidenebis [N-methyl-N- (triethylsilyl) aniline], 4,4'-vinylidenebis [N-ethyl-N- (triethylsilyl) aniline], 4,4'-vinylidenebis [ N-methyl-N- (t-butyldimethylsilyl) aniline], 4,4'-vinylidenebis [N-ethyl-N- (t-butyldimethylsilyl) aniline], 1- [4-N, N-bis (Trimethylsilyl) aminophenyl] -1- [4-N-methyl-N- (trimethylsilyl) aminophenyl] ethylene, and 1- [4-N, N-bis (trimethylsilyl) aminophenyl] -1- [4-N , N-Dimethylaminophenyl] ethylene and the like.

In the present embodiment, a condensation reaction step of causing a condensation reaction in the presence of a condensation accelerator may be further performed after the modification step or before the modification step.

In the conjugated diene-based polymer of the present embodiment, the conjugated diene portion in the conjugated diene polymer chain may be hydrogenated. The method for hydrogenating the conjugated diene portion of the conjugated diene-based polymer is not particularly limited, and a known method can be used.

As a suitable hydrogenation method, a method of hydrogenating by blowing gaseous hydrogen into the polymer solution in the presence of a catalyst can be mentioned. The catalyst is not particularly limited, but for example, a heterogeneous catalyst such as a catalyst in which a noble metal is supported on a porous inorganic substance; a catalyst in which salts such as nickel and cobalt are solubilized and reacted with organic aluminum and the like, titanosen and the like. Examples thereof include homogeneous catalysts such as catalysts using the above-mentioned metallocene. Among these, the titanocene catalyst is preferable from the viewpoint that mild hydrogenation conditions can be selected. Further, hydrogenation of the aromatic group can be carried out by using a supported catalyst of a noble metal.

The hydrogenation catalyst is not particularly limited, but for example, (1) a supported heterogeneous hydrogenation catalyst in which a metal such as Ni, Pt, Pd, Ru is supported on carbon, silica, alumina, silica soil or the like. 2) So-called Cheegler-type hydrogenation catalysts that use organic acid salts such as Ni, Co, Fe, Cr or transition metal salts such as acetylacetone salts and reducing agents such as organic aluminum, (3) Ti, Ru, Rh, Zr. Examples thereof include so-called organometallic complexes such as organometallic compounds such as. Further, the hydrogenation catalyst is not particularly limited, but for example, Japanese Patent Publication No. 42-8704, Japanese Patent Publication No. 43-6636, Japanese Patent Publication No. 63-4841, Japanese Patent Publication No. 1-377970, Special Fair 1- Also mentioned are known hydrogenation catalysts described in Japanese Patent Application Laid-Open No. 53851, Japanese Patent Application Laid-Open No. 2-9041 and Japanese Patent Application Laid-Open No. 8-109219. Preferred hydrogenation catalysts include reaction mixtures of titanocene compounds and reducing organometallic compounds.

In the method for producing a conjugated diene-based polymer of the present embodiment, a deactivating agent, a neutralizing agent, or the like may be added to the polymer solution after the modification step, if necessary.

The inactivating agent is not particularly limited, and examples thereof include water; alcohols such as methanol, ethanol, and isopropanol.

The neutralizing agent is not particularly limited, but is, for example, a carboxylic acid such as stearic acid, oleic acid, or versatic acid (a mixture of carboxylic acids having 9 to 11 carbon atoms and mainly 10 branches); inorganic; Examples include an aqueous acid solution and carbon dioxide.

In the method for producing a conjugated diene polymer of the present embodiment, it is preferable to add a stabilizer for rubber from the viewpoint of preventing gel formation after polymerization and improving the stability during processing.

The stabilizer for rubber is not limited to the following, and known ones can be used. For example, 2,6-di-tert-butyl-4-hydroxytoluene (hereinafter, also referred to as “BHT”). , N-Octadecyl-3- (4'-hydroxy-3', 5'-di-tert-butylphenol) propinate, 2-methyl-4,6-bis [(octylthio) methyl] phenol and other antioxidants are preferred. ..

If necessary, a softening agent for rubber can be added in order to further improve the productivity of the conjugated diene-based polymer of the present embodiment and the processability when the composition is blended with a filler or the like.

The softening agent for rubber is not particularly limited, and examples thereof include extension oil, liquid rubber, and resin.

The method of adding the softening agent for rubber to the conjugated diene-based polymer is not particularly limited, but the softening agent for rubber is added to the conjugated diene-based polymer solution and mixed with the polymer solution containing the softening agent for rubber. A method of desolving the rubber is preferable.

Preferred spreading oils include, for example, aroma oil, naphthenic oil, paraffin oil and the like. Among these, an aroma substitute oil having a polycyclic aromatic (PCA) component of 3% by mass or less according to the IP346 method is preferable from the viewpoint of environmental safety, prevention of oil bleeding, and wet grip characteristics. Examples of the aroma substitute oil include TDAE (Treatd Distillate Aromatic Extracts) shown in Kautschuk Gummi Kunststoffe 52 (12) 799 (1999), MES (Mild Extraction Plastic), and RA.

The preferred liquid rubber is not particularly limited, but is, for example, liquid polybutadiene, liquid, or styrene. Butazin rubber and the like can be mentioned.

As an effect when liquid rubber is added, in addition to improving the processability when the composition is a mixture of a conjugated diene polymer and a filler, the vulcanization transition temperature of the composition can be shifted to the low temperature side. Therefore, there is a tendency to improve the wear resistance, low hysteresis loss property, and low temperature characteristics of the vulcanized product.

Preferred resins are not particularly limited, but are, for example, aromatic petroleum resins, kumaron-inden resins, terpene resins, rosin derivatives (including tung oil resin), tall oils, tall oil derivatives, rosin ester resins, natural and Synthetic terpene resin, aliphatic hydrocarbon resin, aromatic hydrocarbon resin, mixed aliphatic? Aromatic hydrocarbon resin, coumarin? Indene resin, phenol resin, p? tert? Butylphenol? Acetylene resin, phenol? Formaldehyde resin, xylene? Formaldehyde resin, monoolefin oligomer, diolefin oligomer, aromatic hydrocarbon resin, aromatic petroleum resin, hydrogenated aromatic hydrocarbon resin, cyclic aliphatic hydrocarbon resin, hydrogenated hydrocarbon resin, hydrocarbon resin , Hydrocarboned tung oil resin, hydrocarbon oil resin, ester of hydrocarbon oil resin and monofunctional or polyfunctional alcohol and the like. These resins may be used alone or in combination of two or more. When hydrogenating, all unsaturated groups may be hydrogenated or some may be left.

As an effect when the resin is added, in addition to improving the processability when the composition is a mixture of a conjugated diene polymer and a filler, etc., there is a tendency to improve the fracture strength when the vulcanized product is used. In addition, the crow transition temperature of the composition can be shifted to the high temperature side, which tends to improve the wet skid resistance.

The amount of the spreading oil, liquid rubber, resin, or the like added as the softening agent for rubber is not particularly limited, but is preferably 1 part by mass or more and 60 parts by mass with respect to 100 parts by mass of the modified conjugated diene polymer of the present embodiment. Hereinafter, it is more preferably 5 parts by mass or more and 50 parts by mass or less, and further preferably 10 parts by mass or more and 37.5 parts by mass or less.

When a softening agent for rubber is added within the above range, the workability of a composition containing a conjugated diene polymer and a filler and the like is improved, and the fracture strength and wear resistance of a vulcanized product are improved. Tends to be good.

(Solvent removal step)
In the method for producing a conjugated diene-based polymer of the present embodiment, a known method can be used as a method for obtaining the obtained conjugated diene-based polymer from the polymer solution. The method is not particularly limited, but for example, after separating the solvent by steam stripping or the like, the polymer is filtered off, and further dehydrated and dried to obtain the polymer, concentrated in a flushing tank, and then concentrated. Further, a method of devolatile with a vent extruder or the like and a method of directly devolatile with a drum dryer or the like can be mentioned.

(Rubber composition)
The rubber composition of the present embodiment contains a rubber component and a filler of 5.0 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the rubber component.
Further, the rubber component contains 10% by mass or more of the above-mentioned conjugated diene polymer with respect to the total amount (100% by mass) of the rubber component from the viewpoint of low hysteresis loss performance, workability, and improvement of wear resistance. ..

The filler preferably contains a silica-based inorganic filler. Since the rubber composition of the present embodiment contains a silica-based inorganic filler, it tends to be more excellent in processability when it is made into a vulcanized product, and has low wear resistance, breaking strength, and low when it is made into a vulcanized product. It tends to be superior due to the balance between hysteresis loss and wet skid resistance.

Even when the rubber composition of the present embodiment is used for automobile parts such as tires and anti-vibration rubbers and vulcanized rubber applications such as shoes, it is preferable to contain a silica-based inorganic filler.

In the rubber composition of the present embodiment, a rubber-like polymer other than the above-mentioned conjugated diene-based polymer (hereinafter, simply referred to as “rubber-like polymer”) can be used in combination with the above-mentioned conjugated diene-based polymer.

Such a rubber-like polymer is not particularly limited, and is, for example, a conjugated diene-based polymer or a hydrogenated product thereof, a random copolymer of a conjugated diene-based compound and a vinyl aromatic compound or a hydrogenated product thereof, and a conjugate. Examples thereof include a block copolymer of a diene compound and a vinyl aromatic compound or a hydrogenated product thereof, a non-diene polymer, and a natural rubber.

The specific rubber-like polymer is not particularly limited, but for example, butadiene rubber or a hydrogenated product thereof, isoprene rubber or a hydrogenated product thereof, styrene-butadiene rubber or a hydrogenated product thereof, a styrene-butadiene block copolymer. Alternatively, examples thereof include a styrene-based elastomer such as a hydrogenated product thereof, a styrene-isoprene block copolymer or a hydrogenated product thereof, an acrylonitrile-butadiene rubber or a hydrogenated product thereof.

The non-diene polymer is not particularly limited, and for example, an olefin-based elastomer such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, ethylene-butene rubber, ethylene-hexene rubber, and ethylene-octene rubber, and butyl rubber. , Bromineed butyl rubber, acrylic rubber, fluororubber, silicone rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, α, β-unsaturated nitrile-acrylic acid ester-conjugated diene copolymer rubber, urethane rubber, and polysulfide rubber. ..

The natural rubber is not particularly limited, and examples thereof include smoked sheets RSS3 to 5, SMR, and epoxidized natural rubber.

The various rubber-like polymers described above may be modified rubbers to which functional groups having polarities such as hydroxyl groups and amino groups are added. When used for tires, butadiene rubber, isoprene rubber, styrene-butadiene rubber, natural rubber, and butyl rubber are preferably used.

The weight average molecular weight of the rubber-like polymer is preferably 2000 or more and 20000,000 or less, and more preferably 5000 or more and 1500,000 or less, from the viewpoint of the balance between performance and processing characteristics. Further, a rubber-like polymer having a low molecular weight, so-called liquid rubber, can also be used. These rubber-like polymers may be used alone or in combination of two or more.

When the rubber composition of the present embodiment is a rubber composition containing the above-mentioned conjugated diene polymer and the rubber-like polymer, the content ratio (mass ratio) of the above-mentioned conjugated diene polymer to the rubber-like polymer. (The above-mentioned conjugated diene polymer / rubber-like polymer) is preferably 10/90 or more and 100/0 or less, more preferably 20/80 or more and 90/10 or less, and 50/50 or more and 80/20 or less. More preferred.

Therefore, the rubber component preferably contains the above-mentioned conjugated diene polymer in an amount of 10 parts by mass or more and 100 parts by mass or less, and more preferably 20 parts by mass or more and 90 parts by mass or more, based on the total amount (100 parts by mass) of the rubber component. It contains less than or equal to 50 parts by mass, more preferably 50 parts by mass or more and 80 parts by mass or less.

When the content ratio of (the above-mentioned conjugated diene polymer / rubber-like polymer) is within the above range, the vulcanized product has excellent wear resistance and fracture strength, and has low hysteresis loss and wet skid resistance. The balance of is also satisfied.

The filler contained in the rubber composition of the present embodiment is not particularly limited, and examples thereof include silica-based inorganic fillers, carbon black, metal oxides, and metal hydroxides. Among these, silica-based inorganic fillers are preferable.
The filler may be used alone or in combination of two or more.

The content of the filler in the rubber composition of the present embodiment is 5.0 parts by mass or more and 150 parts by mass with respect to 100 parts by mass of the rubber component containing the above-mentioned conjugated diene polymer, and is 20 parts by mass or more. It is preferably 100 parts by mass or less, and more preferably 30 parts by mass or more and 90 parts by mass or less.

In the rubber composition of the present embodiment, the content of the filler is 5.0 parts by mass or more with respect to 100 parts by mass of the rubber component from the viewpoint of exhibiting the effect of adding the filler, and the filler is sufficiently used. From the viewpoint of dispersing and making the workability and mechanical strength of the composition practically sufficient, the amount is 150 parts by mass or less with respect to 100 parts by mass of the rubber component.

The silica-based inorganic filler is not particularly limited, but may be a known, solid particles preferably comprise SiO ₂ or Si ₃ Al as a constituent unit, the main structural units of SiO ₂ or Si ₃ Al Solid particles contained as a component are more preferable. Here, the main component means a component contained in the silica-based inorganic filler in an amount of 50% by mass or more, preferably 70% by mass or more, and more preferably 80% by mass or more.

Specific examples of the silica-based inorganic filler include, but are not limited to, inorganic fibrous substances such as silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, and glass fiber. Further, a silica-based inorganic filler having a hydrophobic surface, a mixture of a silica-based inorganic filler and a non-silica-based inorganic filler can also be mentioned. Among these, silica and glass fiber are preferable, and silica is more preferable, from the viewpoint of strength, abrasion resistance and the like. Examples of silica include dry silica, wet silica, and synthetic silicate silica. Among these silicas, wet silica is preferable from the viewpoint of improving the breaking strength and the balance of wet skid resistance.

From the viewpoint of obtaining practically good wear resistance and breaking strength of the rubber composition, the nitrogen adsorption specific surface area required by the BET adsorption method of the silica-based inorganic filler shall be 100 m ² / g or more and 300 m ² / g or less. Is preferable, and ^{it is more preferably 170 m 2} / g or more and 250 m ² / g or less. If necessary, a silica-based inorganic filler having a relatively small specific surface area (for example, a specific surface area of 200 m ² / g or less) and a silica-based filler having a relatively large specific surface area (for example, 200 m ² / g or more) are used. Inorganic filler) and can be used in combination. In the present embodiment, particularly when a silica-based inorganic filler having a relatively large specific surface area (for example, 200 m ² / g or more) is used, the composition containing the above-mentioned conjugated diene-based polymer has a dispersibility of silica. It is effective in improving, in particular, improving wear resistance, and tends to be able to highly balance good fracture strength and low hysteresis loss.

The content of the silica-based inorganic filler in the rubber composition is preferably 5.0 parts by mass or more and 150 parts by mass, and 20 parts by mass or more and 100 parts by mass with respect to 100 parts by mass of the rubber component containing the conjugated diene polymer. The following is more preferable. In the rubber composition of the present embodiment, the content of the silica-based inorganic filler is 5.0 parts by mass or more with respect to 100 parts by mass of the rubber component from the viewpoint of exhibiting the effect of adding the inorganic filler, and is inorganic. From the viewpoint of sufficiently dispersing the filler and making the workability and mechanical strength of the composition practically sufficient, the content is 150 parts by mass or less with respect to 100 parts by mass of the rubber component.

The carbon black is not particularly limited, and examples thereof include carbon blacks of each class such as SRF, FEF, HAF, ISAF, and SAF. Among these, carbon black having a nitrogen adsorption specific surface area of 50 m ² / g or more and a dibutyl phthalate (DBP) oil absorption of 80 mL / 100 g or less is preferable.

In the rubber composition of the present embodiment, the content of carbon black is preferably 0.5 parts by mass or more and 100 parts by mass or less, preferably 3.0 parts by mass, with respect to 100 parts by mass of the rubber component containing the conjugated diene polymer. More than 100 parts by mass is more preferable, and 5.0 parts by mass or more and 50 parts by mass or less is further preferable. In the rubber composition of the present embodiment, the content of carbon black is 0.5 with respect to 100 parts by mass of the rubber component from the viewpoint of exhibiting the performance required for applications such as tires such as dry grip performance and conductivity. It is preferably 100 parts by mass or more, and preferably 100 parts by mass or less with respect to 100 parts by mass of the rubber component from the viewpoint of dispersibility.

The metal oxide refers to solid particles having the chemical formula MxOy (M represents a metal atom, and x and y each independently represent an integer of 1 to 6) as a main component of the constituent unit. ..

The metal oxide is not particularly limited, and examples thereof include alumina, titanium oxide, magnesium oxide, and zinc oxide.

The metal hydroxide is not particularly limited, and examples thereof include aluminum hydroxide, magnesium hydroxide, and zirconium hydride.

The rubber composition of the present embodiment may contain a silane modifier. The silane modifier has a function of closely interacting with the rubber component and the inorganic filler, and has an affinity or binding group for each of the rubber component and the silica-based inorganic filler. A compound having a sulfur-bonded moiety and an alkoxysilyl group or silanol group moiety in one molecule is preferable. Such compounds are not particularly limited, but are, for example, bis- [3- (triethoxysilyl) -propyl] -tetrasulfide, bis- [3- (triethoxysilyl) -propyl] -disulfide, bis- [. 2- (Triethoxysilyl) -ethyl] -tetrasulfide can be mentioned.

In the rubber composition of the present embodiment, the content of the silane modifier is preferably 0.1 part by mass or more and 30 parts by mass or less, and 0.5 parts by mass or more and 20 parts by mass with respect to 100 parts by mass of the above-mentioned inorganic filler. More preferably, it is 1.0 part by mass or more and 15 parts by mass or less. When the content of the silane modifier is in the above range, the effect of the addition by the silane modifier tends to be more remarkable.

The rubber composition of the present embodiment may contain a softening agent for rubber from the viewpoint of improving the processability thereof.

The amount of the softening agent for rubber added is 100 parts by mass of the rubber component containing the above-mentioned conjugated diene-based polymer, which is previously contained in the above-mentioned conjugated diene-based polymer or other rubber-like polymer for rubber. It is represented by the amount containing the softening agent and the total amount of the softening agent for rubber added when the rubber composition is prepared.

As the softener for rubber, mineral oil or a liquid or low molecular weight synthetic softener is suitable.

Mineral oil-based rubber softeners called process oils or extender oils used to soften, increase volume, and improve processability of rubbers are mixtures of aromatic rings, naphthenic rings, and paraffin chains. , The paraffin chain having 50% or more of carbon atoms in the total carbon is called paraffin-based, and the paraffin ring having 30% or more and 45% or less of all carbon atoms is naphthen-based, and the total number of aromatic carbon atoms is all. Those that account for more than 30% of carbon are called aromatic systems. When the conjugated diene-based polymer of the present embodiment is a copolymer of a conjugated diene compound and a vinyl aromatic compound, a softening agent for rubber to be used having an appropriate aromatic content is familiar with the copolymer. Is preferable because it tends to be good.

In the rubber composition of the present embodiment, the content of the softening agent for rubber is preferably 0 parts by mass or more and 100 parts by mass or less, and more preferably 10 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the rubber component. More preferably, it is 30 parts by mass or more and 90 parts by mass or less. When the content of the softening agent for rubber is 100 parts by mass or less with respect to 100 parts by mass of the rubber component, bleed-out is suppressed and stickiness on the surface of the rubber composition tends to be suppressed.

The method for mixing the conjugated diene polymer with other rubber-like polymers, silica-based inorganic filler, carbon black or other filler, silane modifier, rubber softener and other additives is not particularly limited. For example, a melt-kneading method using a general mixer such as an open roll, a rubbery mixer, a kneader, a single-screw screw extruder, a twin-screw screw extruder, or a multi-screw screw extruder. There is a method of heating and removing the rubber. Of these, a melt-kneading method using a roll, a Banbury mixer, a kneader, or an extruder is preferable from the viewpoint of productivity and good kneading. Further, any of a method of kneading the rubber component and other fillers, silane modifiers, and additives at once, and a method of mixing them in a plurality of times can be applied.

The rubber composition of the present embodiment may be a vulcanized composition that has been vulcanized with a vulcanizing agent. The sulfide is not particularly limited, and examples thereof include radical generators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur compounds. Sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, high molecular weight polysulfur compounds and the like. In the rubber composition of the present embodiment, the content of the vulcanizing agent is preferably 0.01 parts by mass or more and 20 parts by mass or less, and 0.1 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the rubber component. More preferred. As the vulcanization method, a conventionally known method can be applied, and the vulcanization temperature is preferably 120 ° C. or higher and 200 ° C. or lower, more preferably 140 ° C. or higher and 180 ° C. or lower.

At the time of vulcanization, a vulcanization accelerator may be used if necessary. Conventionally known materials can be used as the vulcanization accelerator, and the vulcanization accelerator is not particularly limited. For example, sulfenamide type, guanidine type, thiuram type, aldehyde-amine type, aldehyde-ammonia type, thiazole type, thiourea Examples include system and dithiocarbamate type vulcanization accelerators. The vulcanization aid is not particularly limited, and examples thereof include zinc oxide and stearic acid. The content of the vulcanization accelerator is preferably 0.01 parts by mass or more and 20 parts by mass or less, and more preferably 0.1 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the rubber component.

The rubber composition of the present embodiment contains other softeners and fillers other than those described above, heat-resistant stabilizers, antistatic agents, weather-resistant stabilizers, anti-aging agents, and colorings, as long as the object of the present invention is not impaired. Various additives such as agents and lubricants may be used. As the other softener, a known softener can be used. Specific examples of other fillers include, but are not limited to, calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate. Known materials can be used as the heat-resistant stabilizer, antistatic agent, weather-resistant stabilizer, anti-aging agent, colorant, and lubricant.

The rubber composition of this embodiment is suitably used as a rubber composition for tires. That is, the tire of the present embodiment contains the rubber composition of the present embodiment.

The rubber composition for tires is not particularly limited, but for example, various tires such as fuel-saving tires, all-season tires, high-performance tires, and studless tires: for tire parts such as treads, carcasses, sidewalls, and bead parts. It is available. In particular, the rubber composition for tires is excellent in wear resistance and low hysteresis loss when made into a vulcanized product, and is therefore suitably used for treads of fuel-efficient tires and high-performance tires.

Hereinafter, the present embodiment will be described in more detail with reference to specific examples and comparative examples, but the present embodiment is not limited to the following examples and comparative examples. Various physical properties in Examples and Comparative Examples were measured by the methods shown below.

(Physical properties 1) Molecular weight measurement condition 1: A GPC measuring device (trade name "HLC-8320GPC" manufactured by Toso Co., Ltd.) in which three columns using a (modified) conjugated diene polymer as a sample and a polystyrene gel as a filler are connected. ) Is used to measure the chromatogram using an RI detector (trade name "HLC8020" manufactured by Toso), and the weight average molecular weight (Mw) is calculated based on the calibration curve obtained using standard polystyrene. The number average molecular weight (Mn) and the molecular weight distribution (Mw / Mn) were determined.
The eluent used was THF (tetrahydrofuran) containing 5 mmol / L triethylamine. As the column, three Tosoh product names "TSKgel SuperMultipore HZ-H" were connected, and a Tosoh product name "TSKguardcolum SuperMP (HZ) -H" was connected and used as a guard column in front of the column.
10 mg of the sample for measurement was dissolved in 10 mL of THF to prepare a measurement solution, and 10 μL of the measurement solution was injected into a GPC measuring device and measured under the conditions of an oven temperature of 40 ° C. and a THF flow rate of 0.70 mL / min.

(Physical characteristics 2) Modification rate The modification rate of the modified conjugated diene polymer was measured by the column adsorption GPC method as follows. The measurement was carried out by applying the property of adsorbing the modified basic polymer component to a GPC column using a modified conjugated diene polymer as a sample and using a silica gel as a filler.
The amount of adsorption of the sample and the sample solution containing the low molecular weight internal standard polystyrene to the silica-based column was measured from the difference between the chromatogram measured on the polystyrene-based column and the chromatogram measured on the silica-based column, and the modification rate was determined. I asked.
Specifically, it is as shown below. Further, it was measured under the measurement condition 1 of the above (physical property 4), and the sample whose molecular weight distribution value was 1.6 or more was measured under the following measurement condition 2.
Preparation of sample solution: 10 mg of sample and 5 mg of standard polystyrene were dissolved in 20 mL of THF to prepare a sample solution.
Measurement condition 2: GPC measurement condition using polystyrene column:
Using the trade name "HLC-8320GPC" manufactured by Tosoh Corporation, using 5 mmol / L THF containing triethylamine as an eluent, 10 μL of the sample solution was injected into the apparatus, the column oven temperature was 40 ° C., and the THF flow rate was 0.70 mL /. Chromatograms were obtained using an RI detector under the condition of minutes. As the column, three Tosoh product names "TSKgel SuperMultipore HZ-H" were connected, and a Tosoh product name "TSKguardcolum SuperMP (HZ) -H" was connected and used as a guard column in front of the column.
Calculation method of modification rate: The peak area of the sample is P1, the peak area of standard polystyrene is P2, and the peak area of the chromatogram using the silica column is 100, assuming that the total peak area of the chromatogram using the polystyrene column is 100. The modification rate (%) was calculated from the following formula, assuming that the whole was 100, the peak area of the sample was P3, and the peak area of the standard polystyrene was P4.
Degeneration rate (%) = [1- (P2 × P3) / (P1 × P4)] × 100
(However, P1 + P2 = P3 + P4 = 100)

(Physical characteristics 3) Degree of branching (Bn)
The degree of branching (Bn) of the (modified) conjugated diene polymer was measured as follows by the GPC-light scattering method with a viscosity detector. Using a (modified) conjugated diene polymer as a sample, a gel permeation chromatography (GPC) measuring device (trade name "GPCmax VE-2001" manufactured by Malvern) in which three columns using a polystyrene gel as a filler are connected is used. Using, the light scattering detector, the RI detector, and the viscosity detector (trade name "TDA305" manufactured by Polymer Co., Ltd.) are measured using three connected detectors in this order, and the measurement is performed based on the standard polystyrene. The absolute molecular weight was determined from the results of the light scattering detector and RI detector, and the intrinsic viscosity was determined from the results of the RI detector and viscosity detector.
The linear polymer was used according to the intrinsic viscosity [η] = -3.883M0.771, and the shrinkage factor (g') as the ratio of the intrinsic viscosity corresponding to each molecular weight was calculated. In the formula, M represents the absolute molecular weight.
Then, using the obtained contraction factor (g'), the degree of bifurcation (Bn) defined as g'= 6Bn / [(Bn + 1) (Bn + 2)] was calculated.
As the eluent, tetrahydrofuran containing 5 mmol / L triethylamine (hereinafter, also referred to as “THF”) was used.
The column was used by connecting the trade names "TSKgel G4000HXL", "TSKgel G5000HXL", and "TSKgel G6000HXL" manufactured by Tosoh Corporation.
20 mg of the sample for measurement was dissolved in 10 mL of THF to prepare a measurement solution, and 100 μL of the measurement solution was injected into a GPC measuring device, and the measurement was carried out under the conditions of an oven temperature of 40 ° C. and a THF flow rate of 1 mL / min.

(Physical characteristics 4) Molecular weight (absolute molecular weight) measured by GPC-light scattering method
Using a (modified) conjugated diene polymer as a sample, a chromatogram was measured using a GPC-light scattering measuring device in which three columns using a polystyrene gel as a filler were connected, and the solution viscosity and light scattering method were used. Based on this, the weight average molecular weight (Mw-i) was determined (also referred to as "absolute molecular weight").
The eluent used was a mixed solution of tetrahydrofuran and triethylamine (THF in TEA: 5 mL of triethylamine was mixed with 1 L of tetrahydrofuran to prepare the eluate).
The column was used by connecting a guard column: a product name "TSKguardvolume HHR-H" manufactured by Tosoh Corporation and a column: a product name "TSKgel G6000HHR", "TSKgel G5000HHR" and "TSKgel G4000HHR" manufactured by Tosoh Corporation.
A GPC-light scattering measuring device (trade name "Viscotek TDAmax" manufactured by Malvern) was used under the conditions of an oven temperature of 40 ° C. and a THF flow rate of 1.0 mL / min. 10 mg of the sample for measurement was dissolved in 20 mL of THF to prepare a measurement solution, and 200 μL of the measurement solution was injected into a GPC measuring device for measurement.

(Physical Properties 5) Amount of Bonded Styrene Using a modified conjugated diene polymer containing no rubber softener as a sample, 100 mg of the sample was made up to 100 mL with chloroform and dissolved to prepare a measurement sample. The amount of bonded styrene (mass%) with respect to 100% by mass of the coupling-conjugated diene polymer as a sample was measured by the amount of ultraviolet absorption wavelength (around 254 nm) absorbed by the phenyl group of styrene (Measuring device: Shimadzu Seisakusho). Spectral photometer "UV-2450" manufactured by the company.

(Physical characteristics 6) Microstructure of butadiene part (1,2-vinyl bond amount)
Using a modified conjugated diene polymer containing no softening agent for rubber as a sample, 50 mg of the sample was dissolved in 10 mL of carbon disulfide to prepare a measurement sample. Using a solution cell, the infrared spectrum was measured in the range of 600 to 1000 cm-1, and the absorbance at a predetermined wave number was used by Hampton's method (method described in RR Hampton, Analytical Chemistry 21,923 (1949)). The microstructure of the butadiene portion, that is, the amount of 1,2-vinyl bond (mol%) was determined according to the calculation formula of (Measuring device: Fourier transform infrared spectrophotometer "FT-IR230" manufactured by JASCO Corporation).

(Physical characteristics 7) Polymer Mooney viscosity (Modified) Using a conjugated diene polymer as a sample, using a Mooney viscometer (trade name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.), conforming to JIS K6300, and using an L-shaped rotor. Mooney viscosity was measured.
The measurement temperature was 110 ° C. when an unmodified conjugated diene polymer was used as a sample, and 100 ° C. when a modified conjugated diene polymer was used as a sample.
First, the sample was preheated at the test temperature for 1 minute, the rotor was rotated at 2 rpm, and the torque after 4 minutes was measured to obtain Mooney viscosity (ML (1 + 4)).

(Physical properties 8) Mooney relaxation rate (Modified) Mooney using a conjugated diene polymer as a sample, using a Mooney viscometer (trade name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.), conforming to ISO 289, and using an L-shaped rotor. After measuring the viscosity, the rotation of the rotor was stopped immediately, the torque every 0.1 seconds for 1.6 seconds to 5 seconds after the stop was recorded in Mooney units, and the torque and time (seconds) were plotted in both logarithmic values. The slope of the straight line was calculated, and the absolute value was taken as the Mooney relaxation rate (MSR).

(Example 1) Modified conjugated diene polymer (Sample 1)
An internal volume of 10 L, an internal height (L) to diameter (D) ratio (L / D) of 4.0, an inlet at the bottom and an outlet at the top, and a tank reactor with a stirrer. Two tank-type pressure vessels having a stirrer and a jacket for temperature control were connected as a polymerization reactor.
Preliminarily water-removed 1,3-butadiene was mixed at 27.8 g / min, styrene at 4.94 g / min, and n-hexane at 108.2 g / min. In a static mixer provided in the middle of the pipe for supplying this mixed solution to the inlet of the reactor, n-butyllithium for the residual impurity inactivation treatment was added at 0.062 mmol / min, mixed, and then added to the bottom of the reactor. Supplied continuously. Further, 2,2-bis (2-oxolanyl) propane as a polar substance is vigorously mixed with a stirrer at a rate of 0.067 mmol / min and n-butyllithium as a polymerization initiator at a rate of 0.151 mmol / min1. It was supplied to the bottom of the base reactor and the temperature inside the reactor was maintained at 75 ° C.

The polymer solution was continuously withdrawn from the top of the first reactor, continuously supplied to the bottom of the second reactor, continued the reaction at 80 ° C., and further supplied to the static mixer from the top of the second reactor. When the polymerization was sufficiently stable, while copolymerizing 1,3-butadiene and styrene, from the bottom of the second reactive group, trimethoxy (4-vinylphenyl) silane as a branching agent (in the table, "BS". -1 ”) was added at a rate of 0.0172 mmol / min, and a polymerization reaction and a branching reaction were carried out to obtain a conjugated diene-based polymer having a branched structure. Further, after the polymerization reaction and the branching reaction are stabilized (before modification), a small amount of the conjugated diene polymer solution is withdrawn, an antioxidant (BHT) is added so as to be 0.2 g per 100 g of the polymer, and then the solvent is removed. Then, various physical properties were measured. The measurement results are shown in Table 1.
Next, 1-phenyl-N- (3- (triethoxysilyl) propyl) methaneimine (abbreviated as "a" in the table) was added to the polymer solution flowing out from the outlet of the reactor as a denaturing agent. The mixture was continuously added at a rate of 086 mmol / min, mixed using a static mixer, and subjected to a denaturation reaction. At this time, the time until the denaturant was added to the polymer solution flowing out from the outlet of the reactor was 4.8 minutes, and the temperature was 78 ° C., and the temperature in the polymerization step and the temperature until the denaturant was added. The difference from was 2 ° C. A small amount of the conjugated diene polymer solution after the denaturation reaction was withdrawn, an antioxidant (BHT) was added so as to be 0.2 g per 100 g of the polymer, and then the solvent was removed.

Next, an antioxidant (BHT) is continuously added to the modified polymer solution at 0.033 g / min (n-hexane solution) so as to be 0.2 g per 100 g of the polymer, and the modified reaction is carried out. finished. At the same time as the antioxidant, SRAE oil (trade name "JOMO Process NC140" manufactured by JX Nippon Oil Energy Co., Ltd.) was continuously added to 100 g of the polymer as a softening agent for rubber so as to be 25.0 g. Mixed with a static mixer. The solvent is removed by steam stripping, and a part of the main chain has a 4-branched structure derived from a branching agent (hereinafter, also referred to as “branching agent structure”) which is a compound represented by the following formula (3). Then, a modified conjugated diene polymer (Sample 1) having a bifurcated star-shaped polymer structure derived from the modifier was obtained. Various physical properties of the obtained sample were measured. The measurement results are shown in Table 1.

For the polymer before the addition of the branching agent, the polymer before the modification after the addition of the branching agent, and the polymer in each step after the modification, the molecular weight measured by GPC and the degree of branching measured by GPC with a viscometer were compared. The structure of the modified conjugated diene polymer was identified. Hereinafter, the structure of each sample was identified in the same manner.

（式中、Ｑ¹は、水素原子、並びにその一部分に分岐構造を有していてもよい、炭素数１〜２０のアルキル基及び炭素数６〜２０のアリール基からなる群より選ばれるいずれかを示し、Ｘ¹は、単結合、又は炭素原子、水素原子、窒素原子、硫黄原子、及び酸素原子からなる群より選ばれるいずれかを含有する有機基を示し、Ｙ¹は、炭素数１〜２０のアルキル基、炭素数１〜２０のアルコキシ基、及びハロゲン原子からなる群より選ばれるいずれかを示す。）

(In the formula, Q ¹ is selected from the group consisting of an alkyl group having 1 to 20 carbon atoms and an aryl group having 6 to 20 carbon atoms, which may have a branched structure in a hydrogen atom and a part thereof. X ¹ represents a single bond or an organic group containing any one selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom, a sulfur atom, and an oxygen atom, and Y ¹ represents 1 to 1 carbon atoms. Indicates one selected from the group consisting of 20 alkyl groups, 1 to 20 carbon atoms alkoxy groups, and halogen atoms.)

(Examples 2 to 7) Modified conjugated diene polymer (Samples 2 to 7)
In the same manner as in Example 1, a 4-branched structure derived from the branching agent structure was applied to a part of the main chains except that the production conditions of Example 1 were changed to the production conditions of Examples 2 to 7 shown in Table 1. A modified conjugated diene polymer (Samples 2 to 7) having a denaturing agent-derived bifurcated star-shaped polymer structure was obtained. Various physical properties of the obtained sample were measured. The measurement results are shown in Table 1. Here, Samples 2 to 5 and 7 are modified conjugated diene-based polymers having a 4-branched structure derived from a branching agent structure in a part of the main chain and a bi-branched star-shaped polymer structure derived from a modifier. Sample 6 was a modified conjugated diene polymer having a 4-branched structure derived from a branching agent structure in a part of the main chain and a 4-branched star-shaped polymer structure derived from a modifier. “B”, “c”, and “d” shown as denaturants in Table 1 indicate the following compounds, respectively.
"B": 1- [3- (triethoxysilyl) -propyl] -4-methylpiperazine "c": 2,2-dimethyl-N- (3- (triethoxysilyl) propyl) propan-1-imine " d ": N-ethylidene-3- (trimethoxyryl) -1-propaneamine

(Comparative Example 1) Conjugated Diene Polymer (Sample 8)
An internal volume of 10 L, an internal height (L) to diameter (D) ratio (L / D) of 4.0, an inlet at the bottom and an outlet at the top, and a tank reactor with a stirrer. Two tank-type pressure vessels having a stirrer and a jacket for temperature control were connected as a polymerization reactor.
Preliminarily removed water was mixed under the conditions of 16.3 g / min for 1,3-butadiene, 10.1 g / min for styrene, and 106 g / min for n-hexane. In a static mixer provided in the middle of the pipe for supplying this mixed solution to the inlet of the reactor, n-butyllithium for the residual impurity inactivation treatment was added at 0.054 mmol / min, mixed, and then added to the bottom of the reactor. Supplied continuously. Further, 2,2-bis (2-oxolanyl) propane as a polar substance is vigorously mixed with a stirrer at a rate of 0.059 mmol / min and n-butyllithium as a polymerization initiator at a rate of 0.108 mmol / min1. It was supplied to the bottom of the base reactor and the temperature inside the reactor was maintained at 75 ° C.

The polymer solution was continuously withdrawn from the top of the first reactor, continuously supplied to the bottom of the second reactor, continued the reaction at 80 ° C., and further supplied to the static mixer from the top of the second reactor. When the polymerization was sufficiently stable, a small amount of the conjugated diene polymer solution was withdrawn, an antioxidant (BHT) was added so as to be 0.2 g per 100 g of the polymer, and then the solvent was removed.

After extracting a small amount, the amount of SRAE oil (trade name "JOMO Process NC140" manufactured by JX Nippon Oil Energy Co., Ltd.) is 25.0 g per 100 g of the polymer as a softener for rubber at the same time as the antioxidant. And mixed with a static mixer to obtain a conjugated diene polymer (Sample 8). Various physical properties of the obtained sample were measured. The measurement results are shown in Table 1.

(Comparative Example 2) Modified conjugated diene polymer (Sample 9)
An internal volume of 10 L, an internal height (L) to diameter (D) ratio (L / D) of 4.0, an inlet at the bottom and an outlet at the top, and a tank reactor with a stirrer. Two tank-type pressure vessels having a stirrer and a jacket for temperature control were connected as a polymerization reactor.
Preliminarily water-removed 1,3-butadiene was mixed at 27.8 g / min, styrene at 5.45 g / min, and n-hexane at 108 g / min. In a static mixer provided in the middle of the pipe for supplying this mixed solution to the inlet of the reactor, n-butyllithium for the residual impurity inactivation treatment was added at 0.062 mmol / min, mixed, and then added to the bottom of the reactor. Supplied continuously. Further, 2,2-bis (2-oxolanyl) propane as a polar substance is vigorously mixed with a stirrer at a rate of 0.079 mmol / min and n-butyllithium as a polymerization initiator at a rate of 0.187 mmol / min1. It was supplied to the bottom of the base reactor and the temperature inside the reactor was maintained at 75 ° C.

The polymer solution was continuously withdrawn from the top of the first reactor, continuously supplied to the bottom of the second reactor, continued the reaction at 80 ° C., and further supplied to the static mixer from the top of the second reactor. When the polymerization was sufficiently stable, a small amount of the conjugated diene polymer solution before the addition of the modifier was withdrawn, an antioxidant (BHT) was added so as to be 0.2 g per 100 g of the polymer, and then the solvent was removed to remove various types. The physical properties were measured. The measurement results are shown in Table 1.

Next, 1-phenyl-N- (3- (triethoxysilyl) propyl) methaneimine (abbreviated as "a" in the table) was added to the polymer solution flowing out from the outlet of the reactor as a denaturing agent. The mixture was continuously added at a rate of 086 mmol / min, mixed using a static mixer, and subjected to a denaturation reaction. At this time, the time until the denaturant was added to the polymer solution flowing out from the outlet of the reactor was 4.8 minutes, and the temperature was 78 ° C., and the temperature in the polymerization step and the temperature until the denaturant was added. The difference from was 2 ° C. A small amount of the conjugated diene polymer solution after the denaturation reaction was withdrawn, an antioxidant (BHT) was added so as to be 0.2 g per 100 g of the polymer, and then the solvent was removed.

Next, an antioxidant (BHT) is continuously added to the modified polymer solution at 0.033 g / min (n-hexane solution) so as to be 0.2 g per 100 g of the polymer, and the modified reaction is carried out. finished. At the same time as the antioxidant, SRAE oil (JOMO Process NC140 manufactured by JX Nippon Oil Energy Co., Ltd.) was continuously added to 100 g of the polymer as a softening agent for rubber so as to be 25.0 g, and mixed with a static mixer. , A modified conjugated diene polymer (Sample 9) was obtained. Various physical properties of the obtained sample were measured. The measurement results are shown in Table 1.

(Comparative Example 3) Modified conjugated diene polymer (Sample 10)
An internal volume of 10 L, an internal height (L) to diameter (D) ratio (L / D) of 4.0, an inlet at the bottom and an outlet at the top, and a tank reactor with a stirrer. Two tank-type pressure vessels having a stirrer and a jacket for temperature control were connected as a polymerization reactor.
Preliminarily water-removed 1,3-butadiene was mixed at 25.7 g / min, styrene at 5.04 g / min, and n-hexane at 116 g / min. In a static mixer provided in the middle of the pipe for supplying this mixed solution to the inlet of the reactor, n-butyllithium for the residual impurity inactivation treatment was added at 0.062 mmol / min, mixed, and then added to the bottom of the reactor. Supplied continuously. Further, 2,2-bis (2-oxolanyl) propane as a polar substance is vigorously mixed with a stirrer at a rate of 0.079 mmol / min and n-butyllithium as a polymerization initiator at a rate of 0.187 mmol / min1. It was supplied to the bottom of the base reactor and the temperature inside the reactor was maintained at 75 ° C.

The polymer solution was continuously withdrawn from the top of the first reactor, continuously supplied to the bottom of the second reactor, continued the reaction at 80 ° C., and further supplied to the static mixer from the top of the second reactor. When the polymerization was sufficiently stable, a small amount of the conjugated diene polymer solution before the addition of the modifier was withdrawn, an antioxidant (BHT) was added so as to be 0.2 g per 100 g of the polymer, and then the solvent was removed to remove various types. The physical properties were measured. The measurement results are shown in Table 1.

Next, 1- [3- (triethoxysilyl) -propyl] -4-methylpiperazine (abbreviated as "b" in the table) was added to the polymer solution flowing out from the outlet of the reactor as a denaturing agent. The mixture was continuously added at a rate of .086 mmol / min, mixed using a static mixer, and subjected to a denaturation reaction. At this time, the time until the denaturant was added to the polymer solution flowing out from the outlet of the reactor was 4.8 minutes, and the temperature was 78 ° C., and the temperature in the polymerization step and the temperature until the denaturant was added. The difference from was 2 ° C. A small amount of the conjugated diene polymer solution after the denaturation reaction was withdrawn, an antioxidant (BHT) was added so as to be 0.2 g per 100 g of the polymer, and then the solvent was removed.

Next, an antioxidant (BHT) is continuously added to the modified polymer solution at 0.033 g / min (n-hexane solution) so as to be 0.2 g per 100 g of the polymer, and the modified reaction is carried out. finished. At the same time as the antioxidant, SRAE oil (JOMO Process NC140 manufactured by JX Nippon Oil Energy Co., Ltd.) was continuously added to 100 g of the polymer as a softening agent for rubber so as to be 25.0 g, and mixed with a static mixer. , A modified conjugated diene polymer (Document 11) was obtained. Various physical properties of the obtained sample were measured. The measurement results are shown in Table 1.

(Examples 8 to 14 and Comparative Examples 4 to 6)
Using samples 1 to 10 shown in Table 1 as raw rubbers, rubber compositions containing the respective raw rubbers were obtained according to the formulations shown below.

(Rubber component)
(Modified) conjugated diene polymer (Samples 1-10)
: 70 parts by mass (mass part without softener for rubber)
・ High cis polybutadiene (trade name "UBEPOL BR150" manufactured by Ube Industries, Ltd.)
: 30 parts by mass

(Mixing conditions)
The amount of each compounding agent added is indicated by the number of parts by mass with respect to 100 parts by mass of the rubber component containing no softening agent for rubber.
・ Silica 1 (Product name "Ultrasil 7000GR" manufactured by Evonik Degussa)
Nitrogen adsorption specific surface area 170 m2 / g): 50.0 parts by mass, silica 2 (trade name "Zeosil Premium 200MP" manufactured by Rhodia)
Nitrogen adsorption specific surface area 220 m2 / g): 25.0 parts by mass, carbon black (trade name "Seast KH (N339)" manufactured by Tokai Carbon Co., Ltd.)
: 5.0 parts by mass, silane modifier (trade name "Si75" manufactured by Evonik Degussa, bis (triethoxysilylpropyl) disulfide): 6.0 parts by mass, SRAE oil (product manufactured by JX Nippon Oil Energy Co., Ltd.) Name "Process NC140")
: 32.0 parts by mass (including the amount previously added as a softening agent for rubber contained in samples 1 to 40)
-Zinc oxide: 2.5 parts by mass-Stearic acid: 2.0 parts by mass-Anti-aging agent (N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine): 1.5 parts by mass -Sulfur: 2.2 parts by mass ²⁶
-Vulcanization accelerator 1 (N-cyclohexyl-2-benzothiazil sulfinamide)
1.7 parts by mass, vulcanization accelerator 2 (diphenylguanidine): 2.0 parts by mass, total: 229.9 parts by mass

(Kneading method)
The above materials were kneaded by the following method to obtain a rubber composition. Using a closed kneader (content capacity 0.3L) equipped with a temperature control device, as the first stage kneading, raw material rubber (samples 1 to 10) under the conditions of a filling rate of 65% and a rotor rotation speed of 30 to 50 rpm. , Filler (silica 1, silica 2, carbon black), silane modifier, SRAE oil, zinc oxide and stearic acid were kneaded. At this time, the temperature of the closed mixer was controlled, and each rubber composition (blending) was obtained at an discharge temperature of 155 to 160 ° C.
Next, as the second stage kneading, the formulation obtained above was cooled to room temperature, an antiaging agent was added, and the mixture was kneaded again in order to improve the dispersion of silica. In this case as well, the discharge temperature of the compound was adjusted to 155 to 160 ° C. by controlling the temperature of the mixer. After cooling, as the third stage kneading, sulfur and vulcanization accelerators 1 and 2 were added and kneaded by an open roll set at 70 ° C. Then, it was molded and vulcanized in a vulcanization press at 160 ° C. for 20 minutes. The rubber composition before vulcanization was evaluated for the following (evaluation 1), and the rubber composition after vulcanization was evaluated for the following (evaluation 2) to (evaluation 4). Specifically, it was evaluated by the following method. The results are shown in Table 2.

(Evaluation 1) Emission cohesiveness Immediately after discharging from the pressurized kneader, the unvulcanized modified conjugated diene polymer or conjugated diene polymer produced by the methods shown in Examples and Comparative Examples (first stage of kneading). The cohesiveness (shape) of the kneaded material (immediately after the kneading by the pressurized kneader was completed and discharged) was visually observed, and the discharge cohesiveness was evaluated with a maximum of 4 points per paneler based on the following criteria. This cohesiveness is an index of the processability of the vulcanized product.
V: The edge portion of the sheet is smooth by 50% or less, and the workability is very poor.
IV: The edge of the sheet is smoother than 50% and 60% or less, and is inferior in workability.
III: The edge of the sheet is smoother than 60% and 80% or less, and there is no problem in workability.
II: The edge of the sheet is smoother than 80% and 90% or less, and has excellent workability.
I: The edge of the sheet is 90% ultra-smooth, and the workability is very excellent.

(Evaluation 2) Abrasion resistance Using an Akron wear tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.), the amount of wear at a load of 44.4 N and 1000 rotations was measured in accordance with JIS K6264-2, and the result of Comparative Example 4 Was indexed as 100. The larger the index, the better the wear resistance.

(Evaluation 3) Viscoelasticity parameters The viscoelasticity parameters were measured in the torsion mode using a viscoelasticity tester "ARES" manufactured by Leometrics Scientific. Each measured value was indexed with the result for the rubber composition of Comparative Example 4 as 100.
Tan δ measured at 0 ° C. at a frequency of 10 Hz and a strain of 1% was used as an index of wet grip. The larger the index, the better the wet grip.
Further, tan δ measured at a frequency of 10 Hz and a strain of 3% at 50 ° C. was used as an index of low hysteresis loss property. The smaller the index, the better the low hysteresis loss.

(Evaluation 4) Tensile strength and tensile elongation The tensile strength and tensile elongation were measured according to the tensile test method of JIS K6251, and the result of Comparative Example 41 was set as 100 and indexed. The larger the index, the better the tensile strength and tensile elongation (fracture strength).

The conjugated diene-based polymer according to the present invention has industrial applicability in fields such as tire treads, automobile interior and exterior parts, anti-vibration rubbers, belts, footwear, foam bodies, and various industrial supplies.

Claims (14)

Monovalent group having a conjugated diene polymer chain having a branched structure, in group "-CR ¹ = N-A ^1" (wherein, R ¹ represents a hydrogen atom or a hydrocarbyl group, an A ¹ is an alkoxysilyl group A modified conjugated diene polymer having a modifier residue derived from a modifier having ().
The modifier is a modified conjugated diene polymer which is a compound represented by the following formula (A).

(In the formula, R ¹ and R ² independently represent a hydrocarbyl group having 1 to 20 carbon atoms, R ³ represents an alkanediyl group having 1 to 20 carbon atoms, and R ⁴ and R ⁵ represent an alkanediyl group having 1 to 20 carbon atoms, respectively. It independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and n is an integer of ^{1 to 3.} Any one of a plurality of R 1 and R 2 may be used. They may be the same or different from each other.) The modified conjugated diene polymer according to claim 1, wherein the modification rate is 50% by mass or more. The absolute molecular weight by the GPC-light scattering measurement method with a viscosity detector is 40 × 10 ⁴ or more and 5000 × 10 ⁴ or less.
The degree of branching (Bn) by the GPC-light scattering measurement method with a viscosity detector is 3 or more.
The modified conjugated diene polymer according to claim 1 or 2. A modified conjugated diene-based polymer represented by the following formula (1) and / or the following formula (2).

(In the formula, (A / B / C) indicates a block or random copolymer chain of A, B and C, and A indicates a conjugated diene polymer chain or a hydrogenated product thereof. B is an aromatic vinyl compound unit, C is a structural unit derived from a compound represented by the following formula (3) or the following formula (4), n is an integer of 1 to 20, and R ¹ is an integer. , An alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and R ² and R ³ are independently hydrogen atoms, an alkyl group having 1 to 20 carbon atoms, or 6 to 20 carbon atoms, respectively. R ⁴ and R ⁵ each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, m is an integer of 1 to 3, and l is an integer of 1 to 3. , 1 to 20 and o is an integer from 1 to 20. In the case of a plurality of R ¹ , they may be the same as or different from each other.)

(In the formula, Q ¹ is selected from the group consisting of an alkyl group having 1 to 20 carbon atoms and an aryl group having 6 to 20 carbon atoms, which may have a branched structure in a hydrogen atom and a part thereof. , X ¹ , X ² and X ³ are independent single bonds or organic groups containing any one selected from the group consisting of carbon atom, hydrogen atom, nitrogen atom, sulfur atom and oxygen atom. , Y ¹ , Y ² and Y ³ are each independently selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom. ) A rubber component containing 10% by mass or more of the modified conjugated diene polymer according to any one of claims 1 to 4 with respect to the total amount (100% by mass).
With respect to 100 parts by mass of the rubber component, the filler was added in an amount of 5.0 parts by mass or more and 150 parts by mass or less.
A rubber composition containing. A polymerization step of polymerizing or copolymerizing a conjugated diene compound, or a conjugated diene compound and an aromatic vinyl compound, using an alkali metal compound or an alkaline earth metal compound as a polymerization initiator to obtain a conjugated diene polymer having an active terminal. When,
A branching step of reacting a styrene derivative with the active terminal of the conjugated diene polymer to introduce a branched structure, and
A method for producing a modified conjugated diene-based polymer, which comprises a modification step of reacting an active terminal after the branching step with a compound represented by the following formula (A).

(In the formula, R ¹ and R ² independently represent a hydrocarbyl group having 1 to 20 carbon atoms, R ³ represents an alkanediyl group having 1 to 20 carbon atoms, and R ⁴ and R ⁵ represent an alkanediyl group having 1 to 20 carbon atoms, respectively. It independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and n is an integer of ^{1 to 3.} Any one of a plurality of R 1 and R 2 may be used. They may be the same or different from each other.) The method for producing a modified conjugated diene polymer according to claim 6, wherein the styrene derivative is a compound represented by the following formula (3) and / or the following formula (4).

(In the formula, Q ¹ is selected from the group consisting of an alkyl group having 1 to 20 carbon atoms and an aryl group having 6 to 20 carbon atoms, which may have a branched structure in a hydrogen atom and a part thereof. , X ¹ , X ² and X ³ are independent single bonds or organic groups containing any one selected from the group consisting of carbon atom, hydrogen atom, nitrogen atom, sulfur atom and oxygen atom. , Y ¹ , Y ² and Y ³ are each independently selected from the group consisting of an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and a halogen atom. ) The styrene derivative contains a compound represented by the formula (3).
The method for producing a modified conjugated diene polymer according to claim 7, wherein ^{Q 1} represents a hydrogen atom in the formula (3). The styrene derivative contains a compound represented by the formula (3).
The method for producing a modified conjugated diene polymer according to claim 7, wherein in the formula (3), Q ¹ represents a hydrogen atom and Y ¹ represents an alkoxy group or a halogen atom having 1 to 20 carbon atoms. The styrene derivative contains a compound represented by the formula (4).
The modification according to claim 7, wherein in the formula (4), Y ² represents an alkoxy group or a halogen atom having 1 to 20 carbon atoms, and Y ³ represents an alkoxy group or a halogen atom having 1 to 20 carbon atoms. A method for producing a conjugated diene polymer. The styrene derivative contains a compound represented by the formula (3).
The method for producing a modified conjugated diene polymer according to claim 7, wherein in the formula (3), Q ¹ represents a hydrogen atom and Y ^{1 represents an alkoxy group having 1 to 20 carbon atoms.} The styrene derivative contains a compound represented by the formula (3).
The modified conjugated diene system weight according to claim 7, wherein in the formula (3), Q ¹ represents a hydrogen atom, X ¹ represents a single bond, and Y 1 represents an alkoxy group having 1 to 20 carbon atoms. Manufacturing method of coalescence. The styrene derivative contains a compound represented by the formula (4).
In the above formula (4), X ² represents a single bond, Y ² represents an alkoxy group or a halogen atom having 1 to 20 carbon atoms, X ³ represents a single bond, and Y ³ has 1 carbon atom. The method for producing a modified conjugated diene-based polymer according to claim 7, which shows 20 to 20 alkoxy groups or halogen atoms. A tire containing the rubber composition according to claim 5.