JP6924003B2 - Modified conjugated diene copolymer and its production method - Google Patents

Description

The present invention relates to a modified conjugated diene polymer, a method for producing a modified conjugated diene polymer, and a tire containing the modified conjugated diene polymer.

In recent years, consideration for the environment such as reduction of carbon dioxide emissions has become a social demand. Specifically, there is an increasing demand for fuel efficiency of automobiles. Under these circumstances, there has been a demand for the development of a material having low rolling resistance (low hysteresis loss) as a material for automobile tires, particularly tire red that comes into contact with the ground. On the other hand, from the viewpoint of safety, it is required to develop a material having excellent wet skid resistance and practically sufficient wear resistance and tensile properties. Various modified conjugated diene polymers have been proposed to achieve this. For example, as a rubber for automobile tires, a modified conjugated diene polymer in which the terminal of the conjugated diene polymer is modified with a compound having an amino group and an alkoxysilyl group has been proposed (see Patent Documents 1 to 4). ..

Conventionally, carbon black, silica and the like have been used as the reinforcing filler for tire red. The use of silica has the advantages of being able to improve low hysteresis loss and wet skid resistance. However, while the surface of carbon black is hydrophobic, the surface of silica is hydrophilic, so the affinity between silica and conjugated diene rubber is low, and the dispersibility is poor compared to carbon black. Therefore, it is necessary to separately contain a silane coupling agent or the like in order to improve the dispersibility or to impart a bond between the silica-conjugated diene rubber.

Furthermore, in recent years, the dispersibility of silica in the rubber-like polymer has been improved by introducing a functional group having affinity and reactivity with silica into the active terminal of the rubber-like polymer. Attempts have been made to reduce the hysteresis loss by sealing the modified polymerization end with a bond with silica particles.

For example, Patent Document 1 describes a modified diene-based rubber obtained by reacting the terminal of a conjugated diene-based polymer with alkoxysilanes containing an amino group as a rubber for an automobile tire, and a composition of these and silica. Proposals have been made. Further, Patent Document 2 proposes a modified diene rubber obtained by coupling a polymer active terminal with a polyfunctional silane compound.

On the other hand, by introducing an amino group having an affinity for carbon black at the polymerization initiation terminal of the rubber-like polymer, the polymerization initiation terminal having high mobility can be captured on the carbon black and the hysteresis loss can be reduced. Are known.

By introducing an amino group having an affinity for carbon black at the start end of the rubber-like polymer and introducing alkoxysilanes containing an amino group at the end end, the end of the rubber-like polymer becomes silica and carbon black. Patent Document 3 reports a technique for further reducing hysteresis loss in a modified rubber-like polymer composition captured by both of them and produced by using the modified rubber-like polymer.

Furthermore, when used in automobile tire applications, it has an excellent balance between low hysteresis loss and wet skid resistance, has sufficient wear resistance and tensile properties for practical use, and has excellent workability. As a diene-based polymer and a method for producing the same, a polymerization initiator containing a compound having a specific structure and having at least one nitrogen atom in the molecule and an organic lithium compound is used, and a conjugated diene compound or a conjugated diene compound and an aroma are used. Modification having a polymerization step of obtaining a conjugated diene polymer having an active terminal by polymerizing or copolymerizing a group vinyl compound and a modification step of reacting the conjugated diene polymer with a compound having a specific structure. A method for producing a conjugated diene polymer is reported in Patent Document 4.

Japanese Unexamined Patent Publication No. 2003-171418 International Release No. 07/114203 Japanese Unexamined Patent Publication No. 2001-131230 International Publication No. 2013/035589 Pamphlet

However, although the modified diene rubber disclosed in Patent Documents 1 and 2 has an effect of reducing hysteresis loss in the composition containing silica, there is still room for improvement, and further improvement is required. There is. The modified diene rubber of Patent Document 3 has a further effect of reducing hysteresis loss by introducing functional groups at both ends, but the modified group at the end of the molecular chain of the modified diene rubber during kneading. The reaction between and the inorganic filler such as silica progresses and the viscosity increases, making kneading difficult, and when processing the sheet after kneading, rough skin and breakage of the sheet are likely to occur. It has the problem that it tends to worsen.

Further, the modified conjugated diene polymer of Patent Document 4 still has room for improvement in order to stably obtain a modified conjugated diene polymer having an excellent balance between low hysteresis loss property and wet skid resistance. be.
The present invention has been made in view of the above problems, and when used in an automobile tire application, the present invention has an excellent balance between low hysteresis loss property and wet skid resistance, and has sufficient wear resistance and tensile properties for practical use. It is an object of the present invention to provide a modified conjugated diene-based polymer having an excellent workability.

As a result of diligent studies, the present inventors have found that the conjugated diene polymer in which the ratio of the polymer chains having a specific structure at the end of the polymer chains constituting the conjugated diene polymer is 70% to 98% is an automobile. It has been found that when used in tire applications, it has an excellent balance between low hysteresis loss and wet skid resistance and workability, and has sufficient wear resistance and tensile properties for practical use.
Further, the present inventors add a compound having a specific structure having such a nitrogen atom so that the ratio of the organic lithium as a polymerization initiator to the compound having a specific structure having a nitrogen atom is within a specific range. Therefore, by a production method including a polymerization step of polymerizing a conjugated diene monomer, the terminal of the main polymerized chain has an amino group having a specific structure, and when used in an automobile tire application, wear resistance and tensile properties are exhibited. We have found that a conjugated diene polymer having excellent balance between low hysteresis loss property and wet skid resistance and workability, and having sufficient wear resistance and tensile properties for practical use can be obtained, and completed the present invention. rice field.
That is, the present invention is as follows.

［式（１）中、Ｒ¹及びＲ²は、同一であっても異なっていてもよく、炭素数１〜１２のア
ルキル基、炭素数３〜１４のシクロアルキル基、及び、炭素数６〜２０のアラルキル基か
らなる群より選択されるいずれかである。Ｒ¹及びＲ²は、結合して、隣接した窒素原子と
ともに環状構造を形成していてもよく、その場合のＲ¹及びＲ²は、合計の炭素数が４〜１
２の炭化水素基であって、不飽和結合を有していても、分岐構造を有していてもよい。］

［式（２）中、Ｒ¹及びＲ²は、前記式（１）におけるＲ¹及びＲ²と同様であり、Ｒ³は炭
素数１〜２０のアルキレン基、又は、式（３）〜（５）のいずれかである。ただし、前記
Ｒ³が炭素数１〜２０のアルキレン基の場合は、Ｘは、Ｃｌ、Ｂｒ、Ｉのいずれかであり
、前記Ｒ³が下記式（３）〜（５）のいずれかの場合は、Ｘは水素原子である。］

［２］
前記重合工程において、重合開始の溶液温度を２０〜３５℃の範囲とし、反応ピーク温
度を７５〜８０℃の範囲とし、
分子末端に式（１）又は（２）で表される化合物由来の構造を有する重合鎖の比率が８０
〜９８質量％である、［１］に記載の共役ジエン系重合体の製造方法。
［３］
前記重合工程により得られる、分子末端に式（１）又は（２）で表される化合物由来の
構造を有する重合鎖に、下記式（６）で表されるカップリング剤を反応させるカップリン
グ工程をさらに有し、
前記カップリング剤のカップリング率が７０〜９５質量％である、［１］又は［２］に
記載の共役ジエン系重合体の製造方法。

［式（６）中、Ｒ ⁴ 〜Ｒ ⁷ は、各々独立して、炭素数１〜２０のアルキル基、又は、炭素数６〜２０のアリール基を表し、Ｒ ⁸ は炭素数３〜１０のアルキレン基を表し、Ｒ ⁹ は炭素数１〜２０のアルキレン基を表し、ｍは１又は２の整数であり、ｎは２又は３の整数である。］
［４］
前記カップリング率が７５％〜９５％である、［３］に記載の共役ジエン系重合体の製
造方法。 [1]
After supplying the conjugated diene monomer and the compound represented by the following formula (1) or (2) into the reactor, an organic lithium compound is added as a polymerization initiator to polymerize the conjugated diene monomer. Has a polymerization step to
The ratio of the polymerized chains having the structure derived from the compound represented by the formula (1) or (2) at the molecular end obtained by the polymerization step is 70 to 98% by mass.
A method for producing a conjugated diene-based polymer, wherein in the polymerization step, the solution temperature at the start of polymerization is in the range of 10 to 40 ° C., and the reaction peak temperature is in the range of 75 to 85 ° C.

[In the formula (1), R ¹ and R ² may be the same or different, and have an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 14 carbon atoms, and 6 to 6 carbon atoms. It is one selected from the group consisting of 20 aralkyl groups. R ¹ and R ² may be bonded to form a cyclic structure together with adjacent nitrogen atoms, in which case R ¹ and R ² have a total carbon number of 4 to 1.
The hydrocarbon group of 2 may have an unsaturated bond or a branched structure. ]

[In the formula (2), R ¹ and R ² are the same as R ¹ and R ² in Formula (1), R ³ is an alkylene group having 1 to 20 carbon atoms, or the formula (3) - ( It is one of 5). However, when the R ³ is an alkylene group having 1 to 20 carbon atoms, X is any of Cl, Br, and I, and the R ³ is any of the following formulas (3) to (5). X is a hydrogen atom. ]

[2]
In the polymerization step, the solution temperature at the start of polymerization was set in the range of 20 to 35 ° C, and the reaction peak temperature was set in the range of 75 to 80 ° C.
The ratio of polymerized chains having a structure derived from the compound represented by the formula (1) or (2) at the end of the molecule is 80.
The method for producing a conjugated diene-based polymer according to [1], which is ~ 98% by mass.
[3]
A coupling step of reacting a polymer chain having a structure derived from a compound represented by the formula (1) or (2) at the molecular terminal obtained by the polymerization step with a coupling agent represented by the following formula (6). Have more
The method for producing a conjugated diene polymer according to [1] or [2], wherein the coupling agent has a coupling ratio of 70 to 95% by mass.

[In the formula (6), R ^{4 to} R ⁷ each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and R ⁸ has 3 to 10 carbon atoms. Represents an alkylene group, R ⁹ represents an alkylene group having 1 to 20 carbon atoms, m is an integer of 1 or 2, and n is an integer of 2 or 3. ]
[4]
The method for producing a conjugated diene polymer according to [3], wherein the coupling ratio is 75% to 95%.

The conjugated diene-based polymer of the present invention has an excellent balance between low hysteresis loss property and wet skid resistance, excellent workability, and further has sufficient wear resistance and tensile properties for practical use, and is used for automobiles. It can be used for tire applications.

Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described, but the present invention is not limited to the embodiments shown below, and various modifications are made within the scope of the gist thereof. Can be implemented.

[Conjugated diene polymer]
The conjugated diene-based polymer of the present embodiment has a polymer chain having a structure derived from a compound represented by the following formula (1) or (2) at the molecular terminal in an amount of 70 to 98% by mass. In the present specification, the "polymerized chain" in the present embodiment is a compound obtained by polymerizing a monomeric monomer, and means a single molecule compound. The conjugated diene-based polymer of the present embodiment means a polymer in which such a single molecule compound is a substance composed of two or three or more.

In the above formula (1), R ¹ and R ² may be the same or different, and may be an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 14 carbon atoms, and 6 to 6 carbon atoms. It is one selected from the group consisting of 20 aralkyl groups. R ¹ and R ² may be bonded to form a cyclic structure together with adjacent nitrogen atoms, in which case R ¹ and R ² are hydrocarbon groups having a total carbon number of 4 to 12. It may have an unsaturated bond or a branched structure.

In the above formula (2), R ¹ and R ² are the same as R ¹ and R ² in the formula (1), R ³ is an alkylene group having 1 to 20 carbon atoms, or the formula (3) - ( It is one of 5). However, when the R ³ is an alkylene group having 1 to 20 carbon atoms, X is any of Cl, Br, and I, and the R ³ is any of the following formulas (3) to (5). X is a hydrogen atom.

The ratio of the polymerized chains having the structure derived from the compound represented by the formula (1) or the formula (2) at the molecular terminal is preferably 75% by mass or more, and more preferably 85% by mass or more. preferable. Further, the ratio of the polymerized chains having the structure derived from the compound represented by the formula (1) or the formula (2) at the molecular end is preferably 96% by mass or less.
The ratio of the polymer chains having the structure derived from the compound represented by the formula (1) or (2) at the molecular end is 70 to 98% by mass, which is a polymerization condition in the method for producing a modified conjugated diene polymer described later. Can be achieved by controlling. Further, the ratio of the polymerized chains having the structure derived from the compound represented by the formula (1) or the formula (2) at the molecular terminal can be measured by the method described in Examples described later.

The conjugated diene-based polymer of the present embodiment has a viewpoint of reactivity between the conjugated diene-based polymer and an inorganic filler such as silica, and low hysteresis loss when the conjugated diene-based copolymer is used as a sulfide product. From the viewpoint of the balance between wet skid resistance and wet skid resistance, a polymer chain having a compound-derived structure represented by the formula (1) or (2) at the molecular end and the other end represented by the following formula (6). It is preferable to have a structure derived from a coupling agent.

上記式（６）中、Ｒ⁴〜Ｒ⁷は、各々独立して、炭素数１〜２０のアルキル基、又は、炭素数６〜２０のアリール基を表し、Ｒ⁸は炭素数３〜１０のアルキレン基を表し、Ｒ⁹は炭素数１〜２０のアルキレン基を表し、ｍは１又は２の整数であり、ｎは２又は３の整数である。

In the above formula (6), R ^{4 to} R ⁷ independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and R ⁸ has 3 to 10 carbon atoms. Represents an alkylene group, R ⁹ represents an alkylene group having 1 to 20 carbon atoms, m is an integer of 1 or 2, and n is an integer of 2 or 3.

At this time, the coupling rate of the coupling agent is 70 to 95% by mass. The lower limit of the coupling rate is preferably 75% by mass or more, and more preferably 80% by mass or more. The upper limit of the coupling rate is preferably 93% by mass or less, more preferably 90% by mass or less, from the viewpoint of productivity and workability.
The coupling ratio of 70 to 95% by mass can be achieved by controlling the polymerization conditions in the method for producing a modified conjugated diene polymer described later. In addition, the coupling rate can be measured by the method described in Examples described later.

[Method for producing conjugated diene polymer]
In the method for producing a conjugated diene polymer of the present embodiment, an organic lithium compound is added as a polymerization initiator in the presence of a conjugated diene monomer and a compound represented by the following formula (1) or (2). , A conjugated diene-based polymer having a polymerization step of polymerizing the conjugated diene monomer and having a ratio of polymer chains having a nitrogen atom at the molecular terminal obtained by the polymerization step of 70 to 98% by mass. It is a manufacturing method.
The conjugated diene monomer is preferably used in combination with the conjugated diene monomer and the aromatic vinyl monomer.
Specifically, the method for producing a conjugated diene polymer of the present embodiment includes a conjugated diene monomer, a conjugated diene monomer and an aromatic vinyl monomer, and at least one nitrogen in the molecule. In the presence of the compound represented by the formula (1) or (2) having an atom, an organic lithium compound is added as a polymerization initiator to polymerize the conjugated diene monomer, or the conjugated diene monomer is polymerized. It has a polymerization step of copolymerizing with the aromatic vinyl monomer to bring the ratio of the conjugated diene polymer having a nitrogen atom and an active terminal in the molecule to 70 to 98% by mass.

In the above formula (1), R ¹ and R ² may be the same or different, and may be an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 14 carbon atoms, and 6 to 6 carbon atoms. It is one selected from the group consisting of 20 aralkyl groups. R ¹ and R ² may be bonded to form a cyclic structure together with adjacent nitrogen atoms, in which case R ¹ and R ² are hydrocarbon groups having a total carbon number of 4 to 12. It may have an unsaturated bond or a branched structure.

In the formula (2), R ¹ and R ² are the same as R ¹ and R ² in Formula (1), R ³ is an alkylene group having 1 to 20 carbon atoms, or the formula (3) - (5 ). However, when the R ³ is an alkylene group having 1 to 20 carbon atoms, X is any of Cl, Br, and I, and the R ³ is any of the following formulas (3) to (5). X is a hydrogen atom.

The conjugated diene polymer constituting the modified conjugated diene polymer obtained by the method for producing a modified conjugated diene polymer of the present embodiment is a polymer of a single conjugated diene compound or a weight of a different type of conjugated diene compound. A coalescence, that is, a copolymer or a copolymer of a conjugated diene compound and an aromatic vinyl compound.

In the polymerization step, a polymerization initiator containing a compound having at least one nitrogen atom in the molecule and an organic lithium compound represented by the formula (1) or (2) is used, and the conjugated diene compound or the conjugated diene compound is used. Polymerize or copolymerize with an aromatic vinyl compound to obtain a conjugated diene-based polymer having an active terminal.

In this embodiment, a predetermined polymerization initiator containing a compound having at least one nitrogen atom in the molecule and an organolithium compound is used.
The polymerization initiator is at least one in the molecule represented by the formula (7) or (8) described later, which is obtained by reacting a compound having at least one nitrogen atom in the molecule with an organolithium compound. It contains an organolithium compound having a nitrogen atom, and may contain an organolithium compound having no nitrogen. The organolithium compound represented by the formula (7) or (8) and having at least one nitrogen atom in the molecule may be prepared in advance in a predetermined reactor, or may be polymerized or copolymerized as described later. The organic lithium may be reacted with a compound having at least one nitrogen atom in the molecule at the same time as or before the polymerization or copolymerization.
In order to make the ratio of the polymer chain having the structure derived from the compound represented by the formula (1) or (2) at the molecular terminal in the conjugated diene polymer to 70% to 98% by mass, the organolithium compound and the molecule are intramolecular. The ratio of the compound having at least one nitrogen atom to the organolithium compound is preferably added so that the compound having at least one nitrogen atom in the molecule is equimolar.
The organolithium compound is usually used as a solution dissolved in a solvent, and some of the organolithium compounds actually added are inactive due to the influence of impurities in the solvent and impurities in the monomer as a raw material. Therefore, the compound represented by the formula (1) or (2) is 0.85 per mole of the organolithium compound actually added so that the compound having a nitrogen atom with respect to the active organolithium is equimolar. It is preferable to add ~ 1.0 mol.

(Compound represented by formula (1) or formula (2))
In this embodiment, compounds represented by the formulas (1) and (2), which are compounds having at least one nitrogen atom in the molecule, are used.

In formula (1), R ¹ and R ² may be the same or different, and have an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 14 carbon atoms, and 6 to 20 carbon atoms. It is one selected from the group consisting of aralkyl groups.
The R ¹ and R ² groups are not limited to the following, and include, for example, methyl, ethyl, propyl, butyl, octyl, cyclopropyl, cyclohexyl, 3-phenyl-1-propyl, isobutyl, decyl, and heptyl. , Phenyl and the like.

The compound represented by the formula (1) is not limited to the following, and is, for example, dimethylamine, diethylamine, dibutylamine, dipropylamine, diheptylamine, dihexylamine, dioctylamine, and di (2-). Ethylhexyl) amine, didecylamine, ethylpropylamine, ethylbutylamine, ethylbenzylamine, methylphenethylamine and the like can be mentioned, and if the condition of the above formula (1) is satisfied, these similar substances are included.
The compound represented by the formula (1) is preferably dibutylamine or dihexylamine from the viewpoint of reducing the hysteresis loss of the conjugated diene polymer composition described later and reducing the unpleasant odor of the modified conjugated diene polymer described later. , Dibutylamine is more preferred.

Further, in the formula (1), R ¹ and R ² may be bonded to form a cyclic structure together with adjacent nitrogen atoms, and in that case, R ¹ and R ² have a total of 4 to 4 carbon atoms. It is a hydrocarbon group of 12, and may have an unsaturated bond or a branched structure.
When R ¹ and R ² are bound, examples of the compound represented by the above formula (1) include piperidine, hexamethyleneimine, azacyclooctane, 1,3,3-rimethyl-6-. Examples thereof include azabicyclo [3.2.1] octane, 1,2,3,6-tetrahydropyridine, 3,5-dimethylpiperidine and the like, and are not limited thereto, and are similar to these if the above conditions are satisfied. Including things.
The compound represented by the formula (1) includes piperidine, hexamethyleneimine, and the like from the viewpoint of reducing the hysteresis loss of the modified conjugated diene polymer composition described later and reducing the unpleasant odor of the modified conjugated diene polymer described later. Azacyclooctane, 1,3,3-Ulymethyl-6-azabicyclo [3.2.1] octane, 3,5-dimethylpiperidine are preferred, and piperidine, hexamethyleneimine, 3,5-dimethylpiperidine are more preferred.

In the formula (2), R ¹ and R ² defined the same as R ¹ and R ² in Formula (1). R ³ is an alkylene group having 1 to 20 carbon atoms or any of the following formulas (3) to (5). However, when the R ³ is an alkylene group having 1 to 20 carbon atoms, X is any of Cl, Br, and I, and the R ³ is any of the following formulas (3) to (5). X is a hydrogen atom.
The compound represented by the formula (2) preferably has 2 to 16 carbon atoms of ^{R 3} from the viewpoint of reactivity and interaction with inorganic fillers such as carbon black and silica, and 3 to 10 carbon atoms. Is more preferable.

When R ³ is an alkylene group having 1 to 20 carbon atoms, the compound represented by the formula (2) is not limited to the following, but is, for example, 3-chloro-dimethylpropan-1-amine, 3 -Chloro-diethylpropane-1-amine, 3-chloro-dibutylpropane-1-amine, 3-chloro-dibropyrpropane-1-amine, 3-chloro-diheptylpropan-1-amine, 3-chloro- Dihexylpropan-1-amine, 3-chloropropyl-ethylhexane-1-amine, 3-chloro-didesylpropane-1-amine, 3-chloro-ethylpropane-1-amine, 3-chloro-ethylbutane-1- Amine, 3-chloro-ethylpropane-1-amine, benzyl-3-chloro-ethylpropane-1-amine, 3-chloro-ethylphenethylpropane-1-amine, 3-chloro-methylphenethylpropane-1-amine, 1- (3-chloropropyl) piperidine, 1- (3-chloropropyl) hexamethyleneimine, 1- (3-chloropropyl) azacyclooctane, 6- (3-chloropropyl) -1,3,3-卜Limethyl-6-azabicyclo [3.2.1] octane, 1- (3-chloropropyl) -1,2,3,6-tetrahydropyridine, 1- (3-bromopropyl) hexamethyleneimine, 1- (3) -Iodopropyl) hexamethyleneimine, 1- (3-chlorobutyl) hexamethyleneimine, 1- (3-chloropentyl) hexamethyleneimine, 1- (3-chlorohexyl) hexamethyleneimine, 1- (3-chlorodecyl) Hexamethyleneimine and the like can be mentioned, and if the above conditions are satisfied, these similar substances are included. From the viewpoint of reactivity and interaction with inorganic fillers such as carbon black and silica, 3-chloro-dibutylpropane-1-amine and 1- (3-chloropropyl) hexamethyleneimine are preferable, and more preferably 1. -(3-Chloropropyl) piperidine, 1- (3-chloropropyl) hexamethyleneimine.

When R ³ is any of the formulas (3) to (5), the compound represented by the formula (2) is not limited to the following, but is, for example, N, N-dimethyl-2-. Butenyl-1-amine, N, N-diethyl-2-butenyl-1-amine, N, N-dibutyl-2-butenyl-1-amine, N, N-dipropyl-2-butenyl-1-amine, N, N-diheptyl-2-butenyl-1-amine, N, N-dihexyl-2-butenyl-1-amine, N, N-dioctyl-2-butenyl-1-amine, N, N- (di-2) -Ethylhexyl) -2-butenyl-1-amine, N, N-didecyl-2-butenyl-1-amine, N, N-ethylpropyl-2-butenyl-1-amine, N, N-ethylphtyl-2-butenyl -1-Amine, N, N-ethylbenzyl-2-butenyl-1-amine, N, N-methylphenethyl-2-butenyl-1-amine, N, N-dimethyl-2-methyl-2-butenyl-1 -Amine, N, N-diethyl-2-methyl-2-butenyl-1-amine, N, N-dibutyl-2-methyl-2-butenyl-1-amine, N, N-dipropyl-2-methyl-2 -Butenyl-1-amine, N, N-diheptyl-2-methyl-2-butenyl-1-amine, N, N-dihexyl-2-methyl-2-butenyl-1-amine, N, N-dimethyl -3-Methyl-2-butenyl-1-amine, N, N-diethyl-3-methyl-2-butenyl-1-amine, N, N-dibutyl-3-methyl-2-butenyl-1-amine, N , N-dipropyl-3-methyl-2-butenyl-1-amine, N, N-diheptyl-3-methyl-2-butenyl-1-amine, N, N-dihexyl-3-methyl-2-butenyl -1-amine, 1- (2-butenyl) piperidine, 1- (2-butenyl) hexamethyleneimine, 1- (2-butenyl) azacyclooctane, 6- (2-butenyl) -1,3,3- Limethyl-6-azabicyclo [3.2.1] octane, 1- (2-butenyl) -1,2,3,6-tetrahydropyridine, (2-methyl-2-butenyl) hexamethyleneimine, (3-) Methyl-2-butenyl) hexamethyleneimine and the like can be mentioned, and if the above conditions are satisfied, these are included. From the viewpoint of reducing the hysteresis loss of the modified conjugated diene polymer composition described later, N, N-dibutyl-2-butenyl-1-amine and 1- (2-butenyl) hexamethyleneimine are preferable, and 1- is more preferable. (2-Butenyl) piperidine, 1- (2-butenyl) hexamethyleneimine.

(Organolithium compound)
The organolithium compound in the method for producing a conjugated diene polymer of the present embodiment is not limited to the following, but for example, n-butyllithium, sec-butyllithium, t-butyllithium, n-propyllithium, and the like. Examples thereof include i-propyllithium.

The organolithium compound of the compound represented by the formula (1) or (2) is produced by a reaction when the organolithium compound is added as a polymerization initiator in the presence of the compound represented by the formula (1) or (2). do. The organolithium compound of the compound represented by the formula (1) or (2) reacts with the monomer to initiate polymerization. The organolithium compound of the compound represented by the formula (1) or (2) is not particularly limited as long as it can be anionically polymerized, and the compounds represented by the following formulas (7) and (8) are used. be able to.

In the above formula (7), R ¹ and R ² may be the same or different, and have an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 14 carbon atoms, and 6 to 20 carbon atoms. It is one selected from the group consisting of the aralkyl groups of.
R ¹ and R ² include, but are not limited to, for example, methyl, ethyl, propyl, butyl, octyl, cyclopropyl, cyclohexyl, 3-phenyl-1-flopyl, isobutyl, decyl, heftyl, phenyl. Etc. are included.
The compound represented by the formula (7) is not limited to the following, and is, for example, dimethylaminolithium, diethylaminolithium, dibutylaminolithium, diflopylaminolithium, diheftylaminolithium, and dihexylamino. Examples thereof include lithium, dioctylaminolithium, di-2-ethylhexylaminolithium, didecylaminolithium, ethylpropylaminolithium, ethylbutylaminolithium, ethylbenzylaminolithium, and methylphenethylaminolithium. Including similar products. Dibutylaminolithium and dihexylaminolithium are preferable from the viewpoint of solubility in a solvent and reduction of hysteresis loss of the modified conjugated diene polymer composition described later. More preferably, it is dibutylamine.
In the above formula (7), R ¹ and R ² may be bonded to form a cyclic structure together with adjacent nitrogen atoms, in which case R ¹ and R ² have a total of 4 to 12 carbon atoms. The hydrocarbon group of the above may have an unsaturated bond or a branched structure. When R ¹ and R ² are bonded, the compound represented by the above formula (7) is not limited to the following, but is, for example, piperidinolithium, hexamethyleneiminolithium, lithium aza. Cyclooctane, lithium-1,3,3-卜 lymethyl-6-azabicyclo [3.2.1] octane, 1,2,3,6-tetrahydropyridinolithium, 3,5-dimethylpiperidinolithium, etc. These are included if the above conditions are met. From the viewpoint of solubility of the polymerization initiator in the solvent and reduction of the unpleasant odor of the modified conjugated diene polymer described later, piperidinolithium, hexamethyleneiminolithium, lithium azacyclooctane, lithium-1,3,3- Limethyl-6-azabicyclo [3.2.1] octane, 3,5-dimethylpiperidinolithium is preferred, and piperidinolithium, hexamethyleneiminolithium, and 3,5-dimethylpiperidinolithium are more preferred.

In the above formula (8), R ¹ and R ² may be the same or different, and have an alkyl group having 2 to 12 carbon atoms, a cycloalkyl group having 8 to 14 carbon atoms, and 6 to 20 carbon atoms. It is one selected from the group consisting of the aralkyl groups of. R ³ is represented by an alkylene group having 1 to 20 carbon atoms or any of the following formulas (3) to (5).

When R ³ is an alkylene group having 1 to 20 carbon atoms, the carbon number of R ³ is preferably 2 to 16 from the viewpoint of reactivity and interaction with inorganic fillers such as carbon black and silica, which is more preferable. Is 3 to 10.
When R ³ is an alkylene group having 1 to 20 carbon atoms, the compound represented by the above formula (8) is not limited to the following, but is, for example, (3- (dimethylamino) -propyl). Lithium, (3- (diethylamino) -propyl) lithium, (3- (dipropylamino) -propyl) lithium, (3- (dibutylamino) -propyl) lithium, (3- (dipentylamino) -propyl) lithium, (3- (Dihexylamino) -propyl) lithium, (3- (dioctylamino) -propyl) lithium, (3- (ethylhexylamino) -propyl) lithium, (3- (didecylamino) -propyl) lithium, (3- (3- (didecylamino) -propyl) lithium, (Ethylpropylamino) -propyl) lithium, (3- (ethylbutylamino) -propyl) lithium, (3- (ethylbenzylamino) -propyl) lithium, (3- (methylphenethylamino) -propyl) lithium, ( Examples thereof include 4- (dibutylamino) -butyl) lithium, (5- (dibutylamino) -pentyl) lithium, (6- (dibutylamino) -hexyl) lithium, and (10- (dibutylamino) -decyl) lithium. If the above conditions are met, these similar substances are included. Among the compounds represented by the above formula (8), (3- (dibutylamino) -propyl) lithium is more preferable from the viewpoint of reactivity and interaction with inorganic fillers such as carbon and silica.

When R ³ is any of the formulas (3) to (5), the compound represented by the formula (8) is not limited to the following, but for example, (4-( Dimethylamino) -2-butenyl) lithium, (4- (diethylamino) -2-butenyl) lithium, (4- (dibutylamino) -2-butenyl) lithium, (4- (dipropylamino) -2-butenyl) Lithium, (4- (diheptylamino) -2-butenyl) lithium, (4- (dihexylamino) -2-butenyl) lithium, (4- (dioctylamino) -2-butenyl) lithium, (4- (dihexylamino) -2-butenyl) lithium. -2-Ethylhexylamino) -2-butenyl) lithium, (4- (didecylamino) -2-butenyl) lithium, (4- (ethylpropylamino) -2-butenyl) lithium, (4- (ethylbutylamino)- 2-Butenyl) lithium, (4- (ethylbenzylamino) -2-butenyl) lithium, (4- (methylphenethylamino) -2-butenyl) lithium, (4- (dimethylamino) -2-methyl-2- Butenyl) lithium, (4- (diethylamino) -2-methyl-2-butenyl) lithium, (4- (dibutylamino) -2-methyl-2-butenyl) lithium, (4- (dipropylamino) -2- Methyl-2-butenyl) lithium, (4- (diheptylamino) -2-methyl-2-butenyl) lithium, (4- (dihexylamino) -2-methyl-2-butenyl) lithium, (4- (dimethyl) Amino) -3-methyl-2-butenyl) lithium, (4- (diethylamino) -3-methyl-2-butenyl) lithium, (4- (dibutylamino) -3-methyl-2-butenyl) lithium, (4) -(Dipropylamino) -3-methyl-2-butenyl) lithium, (4- (diheptylamino) -3-methyl-2-butenyl) lithium, (4- (dihexylamino) -3-methyl-2- Butenyl) lithium, including similar substances, if the above conditions are met.
From the viewpoint of reactivity as a polymerization initiator, (4- (dimethylamino) -2-butenyl) lithium, (4- (diethylamino) -2-butenyl) lithium, (4- (dibutylamino) -2-butenyl) Lithium is preferred, more preferably (4- (dibutylamino) -2-butenyl) lithium.

In the above formula (8), R ¹ and R ² may be bonded to form a cyclic structure together with adjacent nitrogen atoms, in which case ^{the total of R 1} and R ² is a hydrocarbon having 4 to 12 carbon atoms. It may be a hydrogen group and may have an unsaturated bond or a branched structure.
When R ¹ and R ² are bonded, the compound represented by the formula (8) is not limited to the following, but for example, (3- (piperidinyl) propyl) lithium, (3- ( Hexamethine reniminyl) propyl) lithium, (3- (heptamethyleneiminyl) propyl) lithium, (3- (octamethyleneiminyl) propyl) lithium, (3- (1,3,3-卜 lymethyl-) 6-Azabicyclo [3.2.1] octanyl) propyl) lithium, (3- (1,2,3,6-tetrahydropyridinyl) propyl) lithium, (2- (hexamethine leminyl) ethyl) lithium , (4- (Hexamethine Reniminyl) Butyl) Lithine, (5- (Hexamethine Reniminyl) Pentyl) Lithine, (6- (Hexamethine Reniminyl) Hexyl) Lithine, (10- (Hexamethine Iminyl) Iminyl) decyl) lithium, (4- (piperidinyl) -2-butenyl) lithium, (4- (hexamethineline iminyl) -2-butenyl) lithium, (4- (heptamethyleneiminyl) -2-butenyl) ) Lithine, (4- (octamethyleneiminyl) -2-butenyl) lithium, (4- (1,3,3-卜 lymethyl-6-azabicyclo [3.2.1] octanyl) -2-butenyl) lithium , (4- (1,2,3,6-tetrahydropyridinyl) -2-butenyl) lithium, (4- (hexamethine reniminyl) -2-methyl-2-butenyl) lithium, (4- ( Hexamethine reniminyl) -3-methyl-2-butenyl) lithium, and if the above conditions are met, these are included.

From the viewpoint of reactivity and interaction with inorganic fillers such as carbon black and silica, (3- (piperidinyl) propyl) lithium, (3- (hexamethynelenimyl) propyl) lithium, (3- (1) , 2,3,6-tetrahydropyridinyl) propyl) lithium, (4- (piperidinyl) -2-butenyl) lithium, (4- (hexamethyneleniminyl) -2-butenyl) lithium are preferred, (3) -(Piperidinyl) propyl) lithium, (4- (piperidinyl) -2-butenyl) lithium, (3- (hexamethynelenimyl) propyl) lithium, (4- (hexametinleniminyl) -2-butenyl) Lithium is more preferred.

The organolithium compound represented by the formula (7) or (8) having at least one nitrogen atom in the molecule may be prepared in advance before the above-mentioned polymerization step, and the preparation method is conventionally known. Method can be applied.

^{When R 3} is an alkylene group having 1 to 20 carbon atoms, the organolithium compound represented by the following formula (8) is obtained by, for example, hydrocarbonizing the amine represented by the following formula (1) and the organolithium compound. It is obtained by reacting in a solvent to prepare a lithium amide compound, reacting it with an alkyl dihalide represented by the following formula (9), and further reacting it with an organic lithium compound.

In the above formula (9), X ¹ and X ² are halogen atoms of any one of I, Br, and Cl, and are different from each other.
Since X ¹ and X ² are different halogen atoms, it is possible to make a difference in reactivity, and by utilizing the difference in reactivity, the halogen having higher reactivity and the lithium amide compound are first selected. The reaction is carried out, and then the remaining halogen is reacted with the organolithium compound to obtain a compound as shown in the above formula (8). R ^3a is an alkylene group having 1 to 20 carbon atoms, preferably an alkylene group having 2 to 16 carbon atoms, and more preferably an alkylene group having 3 to 10 carbon atoms.

The compound represented by the formula (9) is not limited to the following, but for example, 1-bromo-3-chloropropane, 1-bromo-4-chlorobutane, 1-bromo-5-chloropentane, and the like. 1-Bromo-6-chlorohexane, 1-bromo-10-chlorodecane, 1-bromo-3-iodopropane, 1-bromo-4-iodobutane, 1-bromo-5-iodopentane, 1-bromo-6-iodo Hexane, 1-bromo-10-iododecane, 1-chloro-3-iodopropane, 1-chloro-4-iodobutane, 1-chloro-5-iodopentane, 1-chloro-6-iodohexane, 1-chloro-10 -Iodine can be mentioned. Among the compounds represented by the above formula (9), 1-bromo-3-chloropropane, 1-bromo-4-chlorobutane, 1-bromo-5-chloropentane, 1-bromo from the viewpoint of reactivity and safety. -6-chlorohexane and 1-bromo-10-chlorodecane are preferable, and 1-bromo-3-chloropropane, 1-bromo-4-chlorobutane and 1-bromo-6-chlorohexane are more preferable. The reaction temperature when preparing a lithium amide compound using the above formula (1), an organic lithium compound and a hydrocarbon solvent is preferably 0 to 80 ° C, and preferably 10 to 70 ° C from the viewpoint of productivity. The reaction temperature when reacting the lithium amide compound with the compound represented by the formula (9) is preferably −78 to 70 ° C., more preferably −50 to 50 ° C. The reaction temperature when the organic lithium compound is reacted with the obtained compound is preferably −78 to 70 ° C., more preferably −50 to 50 ° C.

An organolithium compound having at least one nitrogen atom in the molecule represented by the formula (8) has the formula (8) when R ³ is represented by any of the formulas (3) to (5). The organolithium compound can be synthesized by the following steps (I) to (IV).

(I) A lithium amide compound is synthesized by reacting a compound represented by the formula (1) with an organic lithium compound in a hydrocarbon solvent.
(II) The obtained lithium amide compound is reacted with butadiene or isoprene in a hydrocarbon solvent.
(III) Alcohol is added to inactivate lithium, and the obtained product is distilled under reduced pressure.
(IV) The product obtained by distillation is reacted with an organolithium compound in a hydrocarbon solvent.

The reaction temperature in the step (I) for preparing the lithium amide compound using the compound represented by the formula (1), the organic lithium compound, and the hydrocarbon solvent is preferably 0 to 80 ° C., and is 10 to 10 from the viewpoint of productivity. 70 ° C. is preferable.

As the alcohol, known materials can be used, but those having a low molecular weight are preferable, for example, methanol, ethanol, isopropanol and the like are preferable, and ethanol is more preferable.
The reaction temperature in step (IV) is preferably 0 to 80 ° C, more preferably 10 to 70 ° C.
When preparing the organolithium compound represented by the formula (7) or (8), a polar compound may be added into the system. As a result, the effect of promoting the production of the lithium compound represented by the formula (7) or (8) and the solubilization effect in the hydrocarbon solvent can be obtained.

Examples of the polar compound include tertiary monoamines, tertiary diamines, chain-like or cyclic ethers, and the like.
The tertiary monoamine is not limited to the following, but is not limited to, for example, lymethylamine, lyethylamine, methyldiethylamine, 1,1-dimethoxy lymethylamine, 1,1-diethoxy lymethylamine, 1,1-diethoxy 卜. Examples thereof include compounds such as triethylamine, N, N-dimethylformamide diisopropyl acetal and N, N-dimethylformamide dicyclohexyl acetal.
The tertiary diamine is not limited to the following, but is, for example, N, N, N', N'-tetramethyldiaminomethane, N, N, N', N'-tetramethylethylenediamine, N, N, N', N'-tetramethylpropanediamine, N, N, N', N'-tetramethyldiaminobutane, N, N, N', N'-tetramethyldiaminopentane, N, N, N', Examples thereof include compounds such as N'-tetramethylhexanediamine, dipiperidinopentane, and dipiperidinoethane.

Examples of the chain ether include, but are not limited to, dimethyl ether, diethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and tetraethylene dimethyl ether.
The cyclic ether is not limited to the following, and includes, for example, tetrahydrofuran, bis (2-oxolanyl) ethane, 2,2-bis (2-oxolanyl) propane, and 1,1-bis (2-oxolanyl). Ethane, 2,2-bis (2-oxolanyl) butane, 2,2-bis (5-methyl-2-oxolanyl) propane, 2,2-bis (3,4,5-rimethyl-2-oxolanyl) propane And other compounds can be mentioned.

Among the polar compounds, from the viewpoint of promoting the production of the organolithium compound represented by the formula (7) or (8) and the solubilizing effect on hydrocarbons, tertiary monoamines such as tetramethylamine and tetraethylamine, 3 N, N, N', N'-tetramethylethylenediamine, which are grade diamines, and tetrahydrofuran, 2,2-bis (2-oxolanyl) propane, which are cyclic ethers, are preferable.
The polar compound may be used alone or in combination of two or more.

When a polar compound is added when preparing the organolithium compound represented by the formula (7) or (8), the amount is within the range of 30 to 50,000 ppm with respect to the solvent used at the time of preparation. It is preferable to add it, and it is more preferable to add it in the range of 200 to 20,000 ppm.
In order to fully exhibit the effects of reaction promotion and solubilization in a solvent, it is preferable to add 30 ppm or more, to secure the degree of freedom of microstructure adjustment in the subsequent polymerization step, and to recover the solvent after polymerization. Considering the separation from the polymerization solvent in the purification step, it is preferable to add at 50,000 ppm or less.

(Polymerization or copolymerization)
In the polymerization step of the present embodiment, the organic lithium compound represented by the formula (7) or (8) is prepared in advance in a predetermined reactor, and the conjugated diene compound is polymerized, or the conjugated diene compound and the aromatic. It may be supplied to a reactor for polymerization with a vinyl compound to carry out a polymerization reaction, or an organic represented by the formula (7) or (8) in a reactor for carrying out polymerization or polymerization described later. A lithium compound may be prepared, and then predetermined monomers, that is, a conjugated diene monomer or an aromatic vinyl monomer may be supplied to the reactor to carry out a polymerization or copolymerization reaction, or the polymerization described later may be carried out. Alternatively, the preparation of the polymerization initiator and the polymerization or copolymerization of the monomers may be carried out at the same time in the reactor for carrying out the polymerization.
When the organolithium compound represented by the above formula (7) or (8) is used, the polymerization initiator may be not only one kind but also a mixture of two or more kinds.

(Conjugated diene monomer, aromatic vinyl monomer)
The conjugated diene compound in the present embodiment is not particularly limited as long as it is a polymerizable monomer, and is, for example, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-. Examples thereof include pentadiene, 3-methyl-1,3-pentadiene, 1,3-heptadiene and 1,3-hexadiene.
Among these, 1,3-butadiene and isoprene are preferable from the viewpoint of easy industrial availability. These may be not only one kind but also two or more kinds in combination. When allenes, acetylenes, etc. are contained as impurities in the conjugated diene compound used in the polymerization step, the reaction with the organolithium compound represented by the formula (7) or (8) or the coupling agent It may inhibit the reaction. Therefore, the total content concentration (mass) of these impurities is preferably 200 ppm or less, more preferably 100 ppm or less, and further preferably 50 ppm or less. Examples of allenes include propadiene, 1,2-butadiene and the like. Examples of acetylenes include ethylacetylene and vinylacetylene.

The aromatic vinyl compound in the present embodiment may be a monomer copolymerizable with the conjugated diene compound and is not particularly limited, and is not particularly limited, for example, styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinyl. Examples thereof include xylene, vinylnaphthalene and diphenylethylene. Among these, styrene is preferable from the viewpoint of easy industrial availability. These may be not only one kind but also two or more kinds in combination.

In the polymerization step of the present embodiment, a polyfunctional aromatic vinyl compound may be used at the same time as the conjugated diene compound and the aromatic vinyl compound, or during the polymerization. As a result, it is possible to control the branching of the molecular chain and prevent cold flow. Examples of the polyfunctional aromatic vinyl compound include divinylbenzene and the like.

The polymerization reaction in this embodiment is preferably carried out in a solvent. The solvent is not limited to the following, and examples thereof include hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons. Specifically, aliphatic hydrocarbons such as butane, pentane, hexane and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane and methylcyclohexane; aromatic hydrocarbons such as benzene, toluene and xylene. And hydrocarbons composed of a mixture thereof and the like.

The above-mentioned conjugated diene monomer, aromatic vinyl monomer, and solvent are used alone, or a mixed solution thereof is subjected to a polymerization reaction in advance, and impurities such as allenes and acetylenes are organically prepared. It is also possible to react the metal compound and treat it. This is preferable because the inhibition of polymerization by the impurities can be prevented, the amount of the active terminal of the polymer becomes high, a sharper molecular weight distribution can be achieved, and a high denaturation rate tends to be achieved.

In the polymerization reaction in this embodiment, a polar compound may be added. The polar compound can randomly copolymerize the aromatic vinyl monomer with the conjugated diene monomer, and can also be used as a vinylizing agent for controlling the microstructure of the conjugated diene portion. It is also effective in improving the polymerization rate. The polar compound is not particularly limited, and 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) flopan and the like. Ethers; tertiary amine compounds such as tetramethylethylenediamine, dipiperidinoethane, lymethylamine, lyethylamine, pyridine, quinuclidine; potassium-t-amylyl, potassium-t-butyrrer, sodium-t- Examples thereof include alkali metal alkoxide compounds such as butylar and sodium amylyl; and phosphine compounds such as diphenylphosphine.
These polar compounds may be used alone or in combination of two or more. It is preferable to use two or more kinds of tetrahydrofuran and other polar compounds because a sharper molecular weight distribution can be achieved.

The amount of the polar compound used is not particularly limited and can be selected according to the purpose and the like. Usually, it is preferably 0.01 to 100 mol with respect to 1 mol of the polymerization initiator.
The polar compound (vinyl agent) can be used in an appropriate amount as a regulator of the microstructure of the polymer-conjugated diene moiety, depending on the desired amount of vinyl bond. Many polar compounds have a randomizing effect that is effective in the copolymerization of the conjugated diene monomer and the aromatic vinyl monomer at the same time, and adjust the distribution of the aromatic vinyl monomer and the amount of the styrene block. Can be used as. As a method for randomizing the conjugated diene monomer and the aromatic vinyl monomer, for example, as described in Japanese Patent Application Laid-Open No. 59-140211, 1,3-butadiene is used during the copolymerization. A method of adding a part intermittently may be used.

As described above, in order to make the ratio of polymer chains having a structure derived from the compound represented by the formula (1) or (2) at the molecular terminal in the conjugated diene polymer at the end of the molecule 70% to 98% by mass, it is organic. It is preferable to add the ratio of the lithium compound to the compound having at least one nitrogen atom in the molecule so that the compound having at least one nitrogen atom in the molecule is equimolar to the organolithium compound. In addition to adjusting the above ratio, the ratio of polymerized chains having a structure derived from the compound represented by the formula (1) or (2) at the molecular terminal in the conjugated diene polymer is 70% to 98% by mass. In addition, it is preferable to adjust the solution temperature at the start of polymerization and the reaction peak temperature.
The solution temperature at which the polymerization starts (hereinafter, also referred to as the polymerization start temperature) is preferably 10 ° C. or higher. Further, in order to obtain a conjugated diene-based polymer in which the ratio of polymer chains having a structure derived from the compound represented by the formula (1) or (2) at the molecular terminal is 70% to 98%, the temperature is 40 ° C. or lower. It is preferable to have.
The solution temperature at the start of the polymerization is more preferably 15 ° C. or higher, and even more preferably 20 ° C. or higher. Further, the solution temperature at the start of the polymerization is more preferably 35 ° C. or lower.

When the organolithium compound represented by the formula (7) or (8) is reacted as a polymerization initiator, the reaction peak temperature is 70 ° C. or higher from the viewpoint of the conversion rate of the monomer and the reaction time. Further, in order to react the coupling agent to make the coupling rate 70% to 95%, the reaction peak temperature is 90 ° C. or lower. The reaction peak temperature is preferably 73 ° C. or higher, more preferably 75 ° C. or higher. The reaction peak temperature is preferably 85 ° C. or lower, more preferably 80 ° C. or lower.

By setting the polymerization start temperature to 10 to 40 ° C. and the reaction peak temperature to the range of 75 to 85 ° C., the ratio of polymer chains having a structure derived from the compound represented by the formula (1) or (2) at the molecular terminal. A conjugated diene-based polymer having a temperature of 70% to 98% by mass can be obtained.
By setting the polymerization start temperature to 20 to 35 ° C. and the reaction peak temperature to the range of 75 to 80 ° C., the ratio of polymer chains having a structure derived from the compound represented by the formula (1) or (2) at the molecular terminal. A conjugated diene-based polymer having a temperature of 80% to 98% by mass can be obtained.

The conjugated diene polymer of the present embodiment grows by an anionic polymerization reaction using an organolithium compound having at least one nitrogen atom in the molecule represented by the above formula (7) or (8) as a polymerization initiator. Can be obtained. Since the conjugated diene polymer of the present embodiment can obtain a modified conjugated diene polymer having a high modification rate, it is preferably a polymer having an active terminal obtained by a growth reaction by living anionic polymerization.

The amount of the bound conjugated diene in the conjugated diene-based polymer obtained by the polymerization step is not particularly limited, but is preferably 50 to 100% by mass, more preferably 60 to 86% by mass.
The amount of the bonded aromatic vinyl in the conjugated diene polymer obtained by the polymerization step is not particularly limited, but is preferably 0 to 50% by mass, more preferably 14 to 40% by mass.

When the amount of the bonded conjugated diene and the amount of the bonded aromatic vinyl are in the above ranges, a vulcanized product having a more excellent balance between low hysteresis loss property and wet skid resistance and satisfying wear resistance and tensile properties can be obtained. 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, it can be measured by a method according to an example described later.

The amount of vinyl bond in the conjugated diene bonding unit is not particularly limited, but is preferably 10 to 75 mol%, more preferably 25 to 65 mol%. When the vinyl bond amount is in the above range, a vulcanized product having a better balance between low hysteresis loss property and wet skid resistance and satisfying wear resistance and tensile properties can be obtained. Here, when the modified conjugated diene polymer is a copolymer of butadiene and styrene, vinyl in the butadiene bonding unit is used by Hampton's method (RR Hampton, Analytical Chemistry, 21,923 (1949)). The amount of binding (1,2-bonding amount) can be obtained.

The conjugated diene-based polymer of the present embodiment may be a random copolymer or a block copolymer.
Examples of the random copolymer include a butadiene-isoprene random copolymer, a butadiene-styrene random copolymer, an isoprene-styrene random copolymer, and a butadiene-isoprene-styrene random copolymer. The composition distribution of each monomer in the copolymer chain is not particularly limited, for example, a completely random copolymer having a composition close to a statistically random composition, or a tapered (gradient) random copolymer having a tapered composition. Examples include polymers. The bonding mode of the conjugated diene, that is, the composition such as 1,4-bonding and 1,2-bonding, may be uniform or may be distributed.

Examples of the block copolymer include a 2-type block copolymer composed of 2 blocks, a 3-type block copolymer composed of 3 blocks, and a 4-type block copolymer composed of 4 blocks. For example, a block made of an aromatic vinyl compound such as styrene is represented by S, and a block made of a conjugated diene compound such as butadiene or isoprene and / or a block made of a copolymer of an aromatic vinyl compound and a conjugated diene compound is represented by B. , SB2 type block copolymer, SBS3 type block copolymer, SBSB4 type block copolymer and the like.
In the above equation, the boundaries of each block do not necessarily have to be clearly distinguished. For example, when the block B is a copolymer of an aromatic vinyl compound and a conjugated diene compound, the aromatic vinyl compounds in the block B may be uniformly distributed or may be distributed in a tapered shape. Further, in the block B, a plurality of portions in which the aromatic vinyl compound is uniformly distributed and / or a plurality of portions in which the aromatic vinyl compound is distributed in a tapered shape may coexist. Further, a plurality of segmen having different aromatic vinyl compound contents may coexist in the block B. When a plurality of blocks S and B are present in the copolymer, the structures such as their molecular weights and compositions may be the same or different.

Low hysteresis loss property when the microstructure (the amount of each bond in the conjugated diene-based copolymer) is in the above range and the glass transition temperature of the copolymer is in the range of -65 ° C to -15 ° C. A more excellent vulcanized product can be obtained by balancing the wet skid resistance with the wet skid resistance. Regarding the glass transition temperature, according to ISO22768: 2006, the DSC curve is recorded while raising the temperature in a predetermined temperature range, and the peak point of the DSC differential curve is defined as the glass transition temperature.

When the conjugated diene-based 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. Specifically, when the copolymer is a butadiene-styrene copolymer, it is weighted by the method of Kolthoff (the method described in IM KOLTHOFF, etal., J. Polym. SCl. 1,429 (1946)). In a known method of decomposing the coalescence and analyzing the amount of polystyrene insoluble in methanol, blocks in which 30 or more aromatic vinyl units are linked are preferably 5% by mass or less, more preferably 5% by mass or less, based on the total amount of the polymer. It is 3% by mass or less.

From the viewpoint of the reactivity between the functional group of the coupling agent and the inorganic filler such as silica, and the balance between the low hysteresis loss property and the wet skid resistance when made into a vulcanized product, the conjugated diene system of the present embodiment. It is preferable to react the active terminal of the polymer with a compound represented by the following formula (6) to obtain a conjugated diene-based polymer.

In the above formula (6), R ^{4 to} R ⁷ independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and R ⁸ has 3 to 10 carbon atoms. Represents an alkylene group, R ⁹ represents an alkylene group having 1 to 20 carbon atoms, m is an integer of 1 or 2, and n is an integer of 2 or 3.
In the compound represented by the formula (6) (hereinafter, also referred to as a coupling agent represented by the formula (6)), m is preferably 2 and n is preferably 3. As a result, the reactivity between the functional group of the modifier and the inorganic filler such as silica is increased, the balance of fuel saving performance and wet grip performance when made into a vulcanized product is improved, and workability is also improved. Can be planned.

The coupling agent represented by the formula (6) is not limited to the following, but is not limited to, for example, 2,2-dimethoxy-1- (3-rimethoxysilylpropyl) -1-aza-2. -Silacyclopentane, 2,2-diethoxy-1- (3-riethoxysilylpropyl) -1-aza-2-silacyclopentane, 2,2-dimethoxy-1- (4-rimethoxysilylbutyl) -1-aza-2-silacyclohexane, 2,2-dimethoxy-1- (5-rimethoxysilylpentyl) -1-aza-2-silacyclopentane, 2,2-dimethoxy-1- (3-dimethoxy) Methylsilylpropyl) -1-aza-2-silacyclopentane, 2,2-diethoxy-1- (3-diethoxyethylsilylpropyl) -1-aza-2-silacyclopentane, 2-methoxy-2-methyl -1- (3-Urimethoxysilylpropyl) -1-aza-2-silacyclopentane, 2-ethoxy-2-ethyl-1- (3-Uriethoxysilylpropyl) -1-aza-2-sila Cyclopentane, 2-methoxy-2-methyl-1- (3-dimethoxymethylsilylpropyl) -1-aza-2-silacyclopentane, 2-ethoxy-2-ethyl-1- (3-diethoxyethylsilylpropyl) ) -1-Aza-2-silacyclopentane and the like.
From the viewpoint of reactivity and interaction between the functional group of the coupling agent and the inorganic filler such as silica, and from the viewpoint of processability, it is preferable that m is 2 and n is 3 in the formula (6). Specifically, 2,2-dimethoxy-1- (3-rimethoxysilylpropyl) -1-aza-2-silacyclopentane, 2,2-diethoxy-1- (3-riethoxysilylpropyl) -1-aza-2-silacyclopentane is preferred.

From the viewpoint of reactivity and interaction between the functional group of the coupling agent and the inorganic filler such as silica, and from the viewpoint of processability, the coupling ratio of the coupling agent represented by the formula (6) is 70 to 70 to. It is 95% by mass. The lower limit of the coupling rate is preferably 75% by mass or more, and more preferably 80% by mass or more. The upper limit of the coupling rate is preferably 93% by mass or less, and more preferably 90% by mass or less. The coupling rate can be controlled within the above range by controlling the reaction peak temperature before adding the coupling agent represented by the formula (6) in the polymerization step.

When the conjugated diene polymer of the present embodiment is a polymer having an active terminal, the reaction temperature, reaction time, etc. when reacting the coupling agent with the active terminal are not particularly limited, but are 0. It is preferable to react at ~ 120 ° C. for 30 seconds or longer.

From the viewpoint of obtaining a sufficient coupling ratio in the coupling between the coupling agent represented by the formula (6) and the conjugated diene polymer of the present embodiment, the silyl group in the compound represented by the formula (6) is used. The total number of moles of the bonded alkoxy groups is preferably 0.6 times or more the number of moles of lithium constituting the above-mentioned polymerization initiator, and the polymer ends are coupled to each other to improve workability and are branched. In addition to obtaining a polymer component, it is preferable that the amount is 3 times or less from the viewpoint of the cost of the modifier.
The total number of moles is more preferably in the range of 0.8 to 2.5 times the number of moles of lithium constituting the above-mentioned polymerization initiator, and more preferably in the range of 0.8 to 2 times. More preferred.

In the method for producing a conjugated diene polymer of the present embodiment, an organic lithium compound is added as a polymerization initiator in the presence of the conjugated diene monomer and the compound represented by the following formula (1) or (2). After the polymerization step of polymerizing the conjugated diene monomer, and further the reaction step with the coupling agent described above (hereinafter, also referred to as a modification step), the conjugated diene polymer is contained in a solution. If necessary, a deactivating agent, a neutralizing agent, or the like may be added. The inactivating agent is not particularly limited, and examples thereof include alcohols such as water, methanol, ethanol, and isopropanol. The neutralizing agent is not particularly limited, and examples thereof include carboxylic acids such as stearic acid, oleic acid, and versatic acid; aqueous solutions of inorganic acids, carbon dioxide gas, and the like.

As a method for obtaining the conjugated diene-based polymer of the present embodiment from the polymer solution, a known method can be used. For example, after separating the solvent by steam ripping or the like, the modified conjugated diene polymer is leaked, and further dehydrated and dried to obtain the modified conjugated diene polymer, which is concentrated in a flushing tank. Further, a method of devolatile with a solvent extruder or the like, a method of directly devolatile with a drum dryer or the like, and the like can be mentioned.

In the coupling step, if the active end of the conjugated diene-based copolymer obtained in the polymerization step reacts with the coupling agent represented by the above formula (6) to obtain a conjugated diene-based polymer. It is good, but its action is presumed as follows.

For example, when an azasilane compound having a cyclic structure such as 2,2-dimethoxy-1- (3-rimethoxysilylpropyl) -1-aza-2-silacyclopentane is used as the coupling agent, a conjugated diene system is used. When the active terminal of the polymer reacts with the alkoxysilyl group of the coupling agent or the Si—N bond portion, a bond between the conjugated diene polymer terminal and Si is formed (see the following formula (10)). For example, when 4 mol of the conjugated diene polymer active terminal reacts with 1 mol of the coupling agent, a modified conjugated diene system in which four molecular chains are coupled as shown in the following formula (10). A polymer is obtained.
Further, a secondary amino group is formed by a reaction with alcohol, water or the like. By using the modified conjugated diene polymer having a secondary amino group and an alkoxysilyl group, the balance between low hysteresis loss property and wet skid resistance when used as a vulcanized product is excellent, and it is practically sufficient. It is considered that wear resistance and tensile properties can be imparted, and excellent processability can also be exhibited.
The mechanism of action of the coupling step is not limited to the above-mentioned example.

The conjugated diene-based polymer obtained in the above-mentioned coupling step has a nitrogen atom-containing functional group at the starting end, but when the conjugated diene-based polymer is used as a vulcanized product, fuel saving performance is obtained. Excellent balance of wet skid resistance, and excellent wear resistance and workability.
When the conjugated diene polymer obtained by the above-mentioned coupling step has one secondary amino group and at least one alkoxysilyl group, the modified conjugated diene polymer is used. As a result, it is possible to provide an excellent balance between low hysteresis loss and wet skid resistance when made into a vulcanized product, impart sufficient wear resistance and tensile properties for practical use, and also exhibit excellent workability. can.
Further, when the conjugated diene-based polymer obtained in the above-mentioned coupling step has a structure of 1 to 6 branches, the modified conjugated diene-based polymer and the polymer composition are excellent in processability. From this point of view, the conjugated diene-based polymer obtained in the coupling step is more preferably having a 1- to 4-branched structure.

The coupling rate of the conjugated diene polymer obtained by the method for producing a conjugated diene polymer of the present embodiment is determined by the amount of adsorption to the column measured by gel permeation chromatography (GPC) using a silica particle-filled column. That is, the proportion of the polymer having a functional group component. The timing for measuring the coupling rate is after deactivating the active end after the coupling step.
As a method for quantifying a polymer having a functional group component, a method of measuring by chromatography capable of separating a modified component containing a functional group and a non-denatured component can be applied. Examples of the method using this chromatography include a method of using a GPC column containing a polar substance such as silica that adsorbs a functional group component as a filler and quantifying the non-adsorbed component by using an internal standard for comparison.

The molecular weight of the modified conjugated diene polymer of the present embodiment (weight average molecular weight: polystyrene conversion) is from 30,000 from the viewpoint of workability and performance such as tensile properties of the modified conjugated diene polymer composition described later. 2 million is preferable. More preferably, it is 50,000 to 1.5 million.
The molecular weight distribution (weight average molecular weight / number average molecular weight) is preferably 1.0 to 3.0, more preferably 1 from the viewpoint of processability and reduction of hysteresis loss of the modified conjugated diene polymer composition described later. .1 to 2.0.
The weight average molecular weight is determined by, for example, measuring a chromatogram using a GPC in which three columns using polystyrene gel as a filler are connected and using a calibration curve using standard polystyrene to calculate the molecular weight. Can be done.
Specifically, tetrahydrofuran (THF) is used as the eluent, and as a column, a guard column: Tosoh TSKgradecolumnHHR-H, a column: Tosoh TSKgelG6000HHR, TSKgelG5000HHR, TSKgelG4000HHR, an oven temperature of 40 ° C., and a THF flow rate of 1 Measurement can be performed using Tosoh's HIC8020 (detector: RI) under the condition of 0.0 ml / min.
For the sample, dissolve 10 mg in the case of a polymer having a narrow molecular weight distribution (1 or more and less than 1.8) and 20 mg in the case of a broad polymer (1.8 or more) in 20 ml of THF, and inject 20 μl. It is preferable to measure it.

Additives such as a rubber stabilizer and a spreading oil may be added to the conjugated diene polymer of the present embodiment.
For the modified 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 particularly limited, and known ones can be used. For example, 2,6-di-tert-butyl-4-hydroxyphenol (BHT) and n-octadecyl-3- (4) are used. Antioxidants such as'-hydroxy-3'5'-di-tert-butylphenol) propine, 2-methyl-4,6-bis [(octylthio) methyl] phenol are preferred.

Further, in order to further improve the processability of the modified conjugated diene polymer of the present embodiment, extender oil can be added to the modified conjugated diene copolymer as needed. The method of adding the spreading oil to the modified conjugated diene-based polymer is not particularly limited, but a method of adding the spreading oil to the polymer solution, mixing the mixture, and desolving the oil-extended copolymer solution is preferable. .. The extension oil is not limited to the following, and examples thereof include aroma oil, naphthenic oil, and paraffin oil. 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 glyph characteristics.

Examples of the aroma substitute oil include TDAE (TreatedDistimateAromaticExtracts) MES (MildExtractionSolvate) shown in kaustschukGummlKunststoffe52 (12) 799 (1999), and RAE (ResidualAroma) and the like.
The amount of the spreading oil added is not particularly limited, but is usually 10 to 60 parts by mass, preferably 20 to 37.5 parts by mass, based on 100 parts by mass of the modified conjugated diene polymer.

[Conjugated diene polymer composition]
The conjugated diene-based polymer of the present embodiment can be used by blending with a rubber component, and further, a silica-based inorganic filler or the like can be blended to prepare a conjugated diene-based polymer composition. The conjugated diene polymer composition is not particularly limited as long as it contains the conjugated diene polymer of the present embodiment. For example, a rubber component containing 20 parts by mass or more of the modified conjugated diene polymer of the present embodiment. Examples thereof include a composition containing 100 parts by mass and 0.5 to 300 parts by mass of a silica-based inorganic filler.

(Rubber component)
As the rubber component, a rubber-like polymer other than the conjugated diene polymer of the present embodiment can be used in combination with the conjugated diene polymer of the present embodiment.
The rubber-like polymer other than the conjugated diene polymer of the present embodiment is not particularly limited, and is, for example, a conjugated diene polymer or a hydrogenated product thereof, or a random common weight of the conjugated diene compound and a vinyl aromatic compound. Examples thereof include a coalescence or a hydrogenated product thereof, a block copolymer of a conjugated diene compound and a vinyl aromatic compound or a hydrogenated product thereof, a non-diene polymer, a natural rubber and the like.
Specifically, 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 or a hydrogenated product thereof, and a styrene-isoprene block copolymer weight. Examples thereof include styrene-based elastomers such as coalescing or hydrogenated products thereof, acrylonitrile-butadiene rubber or hydrogenated products thereof.

Examples of the non-diene polymer include olefin elastomers such as ethylene-fluoropyrene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, ethylene-butene rubber, ethylene-hexene rubber, and ethylene-octene rubber, butyl rubber, brominated butyl rubber, and acrylic. Examples thereof include 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 various rubber-like polymers described above may be modified rubbers to which a functional group having polarity such as a hydroxyl group or an amino group is added. The weight average molecular weight is preferably 2,000 to 2,000,000, more preferably 5,000 to 1,500,000 from the viewpoint of the balance between performance and processing characteristics. Further, so-called liquid rubber having a low molecular weight can also be used. The rubber-like polymer may be used alone or in combination of two or more.

When the modified conjugated diene polymer of the present embodiment and the rubber-like polymer described above are contained in the rubber component, the blending ratio (mass ratio) of these is the modified conjugated diene polymer / rubber-like weight. As a coalescence, 20/80 to 100/0 is preferable, 30/70 to 90/10 is more preferable, and 50/50 to 80/20 is even more preferable. When the blending ratio of the modified conjugated diene polymer / rubber-like polymer is within the above range, the balance between low hysteresis loss property and wet skid resistance is further excellent, and the vulcanized product further satisfies the wear resistance and tensile properties. Can be obtained.

(Silica-based inorganic filler)
By dispersing the silica-based inorganic filler in the conjugated diene-based polymer of the present embodiment, when it is made into a vulcanized product, it has an excellent balance between low hysteresis loss property and wet skid resistance, which is sufficient for practical use. It has wear resistance and tensile properties, and can impart excellent workability. 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 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.

Examples of the silica-based inorganic filler include, but are not limited to, silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, glass fiber and other inorganic fibrous substances. .. Further, a silica-based inorganic filler having a hydrophobic surface or a mixture of a silica-based inorganic filler and a non-silica-based inorganic filler can also be used.
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, wet silica is preferable from the viewpoint of improving the fracture characteristics and the balance of wet skid resistance, and from the viewpoint of obtaining practically good wear resistance and fracture characteristics in the modified conjugated diene polymer composition. a nitrogen adsorption specific surface area determined by the BET adsorption method of the silica-based inorganic filler is preferably 100 to 300 m ² / g, more preferably 170~250m ² / g.

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 inorganic filler having a relatively large specific surface area (for example, 200 m ² / g or more) are filled. It can be used in combination with an agent. As a result, good wear resistance and fracture characteristics and low hysteresis loss can be highly balanced.

As described above, the content of the silica-based inorganic filler in the modified conjugated diene-based polymer composition is 0.5 to 300 mass by mass with respect to 100 parts by mass of the rubber component containing the modified conjugated diene-based polymer of the present embodiment. 5 to 200 parts by mass is preferable, and 20 to 100 parts by mass is more preferable.
The content of the silica-based inorganic filler is 0.5 parts by mass or more from the viewpoint of exhibiting the effect of adding the inorganic filler, while the inorganic filler is sufficiently dispersed to improve the processability and tensile properties of the composition. From the viewpoint of practically sufficient, the amount is 300 parts by mass or less.

(Carbon black)
Carbon black may be contained in the conjugated diene-based polymer composition. The carbon black is not particularly limited, and for example, carbon black of each class such as SRF, FEF, HAF, ISAF, and SAF can be used. 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 is preferable.
The content of carbon black is preferably 0.5 to 100 parts by mass, more preferably 3 to 100 parts by mass, and 5 to 50 parts by mass with respect to 100 parts by mass of the rubber component containing the conjugated diene polymer of the present embodiment. Is even more preferable. The blending amount of carbon black is preferably 0.5 parts by mass or more from the viewpoint of exhibiting the performance required for applications such as tires such as dry grip performance and conductivity, and 100 parts by mass or less from the viewpoint of dispersibility. Is preferable.

(Metal oxides / metal hydroxides)
The conjugated diene-based polymer composition may contain a metal oxide or a metal hydroxide in addition to the above-mentioned silica-based inorganic filler or carbon black. The metal oxide refers to a solid particle whose main component is the chemical formula M _x O _y (M represents a metal atom, and x and y each represent an integer of 1 to 6) as a constituent unit, and is particularly limited. However, for example, alumina, titanium oxide, magnesium oxide, zinc oxide and the like can be used. Further, a mixture of a metal oxide and an inorganic filler other than the metal oxide can also be used.
The metal hydroxide is not particularly limited, and examples thereof include aluminum hydroxide, magnesium hydroxide, and zirconium hydride.

(Silane coupling agent)
The conjugated diene-based polymer composition may contain a silane coupling agent. The silane coupling agent has a function of closely interacting with the rubber component and the silica-based inorganic filler, and has an affinity or binding group for each of the rubber component and the silica-based inorganic filler. Generally, a compound having a sulfur-bonded moiety, an alkoxysilyl group, and a silanol group moiety in one molecule is used. Specifically, bis- [3- (riethoxysilyl) -propyl] -tetrasulfide, bis- [3- (riethoxysilyl) -propyl] -disulfide, bis- [2- (riethoxysilyl) -propyl ) -Ethyl] -Tetrasulfide and the like.
The content of the silane coupling agent is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, and 1 to 15 parts by mass with respect to 100 parts by mass of the above-mentioned silica-based inorganic filler. More preferred. When the blending amount of the silane coupling agent is within the above range, the above-mentioned addition effect of the silane coupling agent can be made more remarkable.

(Rubber softener)
The conjugated diene-based polymer composition may contain a softening agent for rubber in order to improve processability. As the softener for rubber, mineral oil or a liquid or low molecular weight synthetic softener is suitable.
The softening agent for mineral oil-based rubber contains an oil called process oil or extender oil used for softening, increasing the volume, and improving workability of rubber, and among these, aromatic ring, naphthen ring, and so on. A mixture of paraffin chains and paraffin chains in which the number of carbon atoms in the paraffin chain accounts for 50% or more of the total carbon is called paraffin type. Those exceeding 30% are called aroma type.
As the softening agent for rubber used in the conjugated diene-based polymer composition, from the viewpoint of environmental safety, prevention of oil bleeding, and wet grip characteristics, the polycyclic aromatic (PCA) component by the IP346 method is 3% by mass. Aroma substitute oil of% or less is preferable.
The content of the softening agent for rubber is preferably 0 to 100 parts by mass, more preferably 10 to 90 parts by mass, and 30 to 90 parts by mass with respect to 100 parts by mass of the rubber component containing the modified conjugated diene polymer. More preferred. If the content of the softener for rubber exceeds 100 parts by mass with respect to 100 parts by mass of the rubber component, bleed-out is likely to occur and the surface of the composition may become sticky.

(Other additives)
The conjugated diene-based polymer composition contains other softeners and fillers other than those described above, as well as various additives such as heat-resistant stabilizers, antistatic agents, weather-resistant stabilizers, anti-aging agents, colorants, and lubricants. You may use it. As the other softener, a known softener can be used. Specific examples of other fillers include calcium carbonate, magnesium carbonate, aluminum sulfate, barium sulfate and the like. Known materials can be used as the heat-resistant stabilizer, antistatic agent, weather-resistant stabilizer, anti-aging agent, colorant, and lubricant.

The method for producing the conjugated diene-based polymer composition is not particularly limited. For example, the above-mentioned rubber component, silica-based inorganic filler, and other various materials described above, for example, open roll, vanbury mixer, kneader, single-screw screw extruder, twin-screw screw extruder, multi-screw screw. Examples thereof include a method of melt-kneading using a general mixer such as an extruder, and a method of dissolving and mixing each component and then heating and removing the solvent.
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, either a method of kneading the conjugated diene polymer and various materials at once or a method of mixing them in a plurality of times can be applied.

The conjugated diene-based polymer composition is preferably used as a vulcanized product.
The vulcanized product is a conjugated diene polymer, a silica-based inorganic filler, an inorganic filler such as carbon black if necessary, a rubber-like polymer other than the modified conjugated diene polymer, a silane coupling agent, and rubber. It can be obtained by mixing with a softening agent, a vulcanizing agent, a vulcanization accelerator / auxiliary agent, etc., and heating and vulcanizing.

As the sulfide agent, for example, radical generators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur and sulfur compounds can be used. Sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, high molecular weight polysulfur compounds and the like.
The content of the vulcanizing agent is usually 0.01 to 20 parts by mass, preferably 0.1 to 15 parts by mass, based on 100 parts by mass of the rubber component containing the conjugated diene polymer of the present embodiment. As the vulcanization method, a conventionally known method can be applied, and the vulcanization temperature is usually 120 to 200 ° C., preferably 140 to 180 ° C.

As the vulcanization accelerator, conventionally known materials can be used, for example, sulfenamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, thiourea-based, dithiocarbamate-based. And other vulcanization accelerators.
The content of the vulcanization accelerator is usually 0.01 to 20 parts by mass, preferably 0.1 to 15 parts by mass, based on 100 parts by mass of the rubber component containing the conjugated diene polymer of the present embodiment. ..
Further, as the vulcanization aid, zinc oxide, stearic acid and the like can be used.

The conjugated diene-based polymer composition can be crosslinked by adding a vulcanizing agent, various compounding agents, etc., and can be used as a rubber composition for producing a desired rubber product. The rubber composition obtained by cross-linking the conjugated diene polymer composition can be used for tires, anti-vibration rubbers, and various industrial products.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples. The sample was analyzed by the method shown below.

(1) Amount of bound styrene A 100 mg sample of the modified conjugated diene polymer obtained in Examples and Comparative Examples described later was made up to 100 ml with chloroform and dissolved to prepare a measurement sample.
Made by JASCO: Using V-550, the bound styrene content (wt%) was measured by absorption of UV of 254 nm by the phenyl group of styrene.

(2) Microstructure of butadiene part (1,2-vinyl bond amount)
50 mg of the modified conjugated diene polymer sample obtained in Examples and Comparative Examples described later was dissolved in 50 ml of carbon disulfide, and the infrared spectrum was measured in the range of ^{600 to 1000 cm -1 using a solution cell.} From the predetermined absorbance, the microstructure (1,2-vinyl bond amount (mol%)) of the butadiene moiety was determined according to the calculation formula of Hampton's method.

(3) Mooney Viscosity of Modified Conjugated Diene Polymer The Mooney viscosity of the modified conjugated diene polymer obtained in Examples and Comparative Examples described later was measured as follows.
The Mooney viscosity was measured using a Mooney viscometer (manufactured by Ueshima Seisakusho Co., Ltd., "VR1132") in accordance with JIS K6300 (ISO289-1). The measurement temperature was 100 ° C. First, after preheating the sample for 1 minute, the rotor was rotated at 2 rpm, and the torque after 4 minutes was measured to obtain Mooney viscosity (ML1 + 4).

(4) Peak molecular weight The peak molecular weight is determined by using a polystyrene-based gel column (column: PLgelMiniMix-C x 3, column oven temperature 35 ° C., JASCO Corporation 856-CO, THF) using the copolymer before the addition of the nitrogen-containing cyclic compound as a sample. A chromatograph of GPC (Waters 2695) with a flow rate of 0.35 ml, a sample concentration of 0.1% by weight, an injection volume of 50 μl, and an RI detector: Waters 2414) was measured. In addition, a calibration curve prepared using commercially available standard monodisperse polystyrene having a known molecular weight was used, and the weight average molecular weight and the number average molecular weight were obtained from the obtained GPC chromatograms to obtain molecular weight distribution values.

(5) Ratio of conjugated diene polymer having nitrogen atom By applying the property that the conjugated diene polymer having nitrogen atom is adsorbed on the GPC column using silica gel as a filler, the sample and standard polystyrene (polystyrene) having a molecular weight of 5000 are applied. Using a sample solution containing (does not adsorb to the column), a polystyrene gel column (column: PLgelMiniMix-C x 3, column oven temperature 35 ° C.: Nippon Kogaku 856-CO, THF flow rate 0.35 mI, RI detector: Waters 2414) GPC (Waters 2695) and silica gel column (column: Zorbox PSM1000-S 1 piece, PSM300-S 1 piece and PSM60-S 1 piece, total 3 pieces, column oven temperature 35 ° C.: manufactured by Nippon Kogaku Both chromatograms of GPC (WATERS 2695) of 856-CO, THF flow rate 0.7 ml / min, RI detector: Waters 2414) were measured using the RI detector, and the difference between them was transferred to the silica column. The adsorption amount of the conjugated diene polymer having a nitrogen atom is measured, and the ratio of the polymer chains having the structure represented by the formula (1) or (2) at the molecular end in the conjugated diene polymer ( Hereinafter, it is also referred to as "ratio of polymer chains having a nitrogen atom"). The sample was measured by dissolving 10 mg in 20 ml of THF together with 5 mg of standard polystyrene and injecting 100 μl. As a specific procedure, it was calculated by the following formula from the area (%) measured by the polystyrene-based gel column and the silica-based gel column.

The definitions of a, b, c, and d in the above formula are as follows.
a: Area (%) of the total polymer measured with a polystyrene gel (PLgel)
b: Area (%) of low molecular weight internal standard polystyrene (PS) measured with polystyrene gel.
c: Area (%) of the total polymer measured on a silica-based column (Zorbox).
d: Area (%) of low molecular weight internal standard polystyrene (PS) measured on a silica-based column (Zorbox).

(6) Coupling rate The coupling rate is determined by using a conjugated diene polymer before the addition of the coupling agent as a sample, and using a polystyrene gel column (column: PLgelMiniMix-C x 3, column oven temperature 35 ° C.: JASCO Corporation 856-). A chromatograph of GPC (Waters 2695) of CO, THF flow rate 0.35 ml, sample concentration 0.1% by weight, injection volume 50 μl, RI detector: Waters 2414) was measured. Calculated from the ratio of the uncoupled (low molecular weight peak) peak area to the coupled (high molecular weight peak) peak area

[Example 1]
Using an autoclave with an internal volume of 100 L and a stirrer and a jacket and capable of temperature control as a reactor, 5,920 g of 1,3-butadiene, 2,080 g of styrene, and cyclohexane from which impurities have been removed in advance were used. 52,000 g, 7.18 g of piperidine (Pp), 8 g of tetrahydrofuran (THF) and 6 g of 2,2-bis (2-oxolanyl) propane (BOP) as polar substances were placed in the reactor, and the temperature inside the reactor was increased. Was maintained at 24 ° C.
As a polymerization initiator, 6 g of n-butyllithium was supplied to the reactor.
After the start of the polymerization reaction, the temperature inside the reactor began to rise due to the heat generated by the polymerization, and the final temperature inside the reactor reached 79 ° C. A small amount of this polymer solution was collected, the solvent was removed by steam ripping, and the mixture was dried by a dryer to obtain a conjugated diene polymer (Sample A).
As a result of analyzing Sample A, the amount of bound styrene was 26% by mass and the amount of bound butadiene was 74% by mass. The vinyl bond amount (1,2-bond amount) of the microstructure of the butadiene portion calculated from the measurement result using the infrared spectrophotometer according to the Hampton method was 59%. The proportion of polymerized chains having a nitrogen atom was 93%. The analysis results of Sample A are shown in Table 1.

[Example 2]
Using an autoclave with an internal volume of 100 L and a stirrer and a jacket and capable of temperature control as a reactor, 5,920 g of 1,3-butadiene, 2,080 g of styrene, and cyclohexane from which impurities have been removed in advance were used. 52,000 g, 7.18 g of piperidine (Pp), 8 g of tetrahydrofuran (THF) and 6 g of 2,2-bis (2-oxolanyl) propane (BOP) as polar substances were placed in the reactor, and the temperature inside the reactor was increased. Was maintained at 20 ° C.
As a polymerization initiator, 6 g of n-butyllithium was supplied to the reactor.
After the start of the polymerization reaction, the temperature inside the reactor began to rise due to the heat generated by the polymerization, and the final temperature inside the reactor reached 73 ° C. A small amount of the polymer solution was collected 2 minutes after the reaction temperature peak was reached (conjugated diene polymer after drying treatment (Sample B-1)), and 3 minutes after the reaction temperature peak was reached after a small amount was collected, the reactor was used. 4.9 g of 2,2-dimethoxy-1- (3-Urimethoxysilylpropyl) -1-aza-2-silacyclopentane (X-1) was added to the mixture, and a coupling reaction was carried out for 5 minutes. In this polymer solution, 30 g of n-octadecyl-3- (3,5-di-t-butyl-4-hydrooxyphenyl) -propionate as an antioxidant and 4,6-bis (octylthiomethyl)- After adding 12 g of o-cresol, the solvent was removed by steam steam ripping and dried with a dryer to obtain a modified conjugated diene polymer (Sample B-2).
As a result of analyzing Sample B-1, the amount of bound styrene was 26% by mass and the amount of bound butadiene was 74% by mass. The vinyl bond amount (1,2-bonding amount) of the microstructure of the butadiene portion calculated from the measurement result using the infrared spectrophotometer according to the Hampton method was 56%. The proportion of polymerized chains having a nitrogen atom was 96%. As a result of measuring the coupling rate in sample B-2, the coupling rate was 84%.

[Example 3]
Using an autoclave with an internal volume of 100 L and a stirrer and a jacket and capable of temperature control as a reactor, 5,920 g of 1,3-butadiene, 2,080 g of styrene, and cyclohexane from which impurities have been removed in advance were used. 52,000 g, 7.18 g of piperidine (Pp), 8 g of tetrahydrofuran (THF) and 6 g of 2,2-bis (2-oxolanyl) propane (BOP) as polar substances were put into the reactor, and the temperature inside the reactor was adjusted. It was maintained at the polymerization initiation temperature shown in Table 1.
The conjugated diene polymer after the drying treatment (Sample C-1) and the conjugated diene polymer after the coupling (Sample C) were obtained in the same manner as in Example 2 except that the polymerization start temperature was changed as shown in Table 1. -2) was prepared. Table 1 shows the reaction temperature peak, the ratio of polymer chains having nitrogen atoms obtained from sample C-1, and the coupling ratio of the conjugated diene-based polymer after coupling obtained from sample C-2.

[Example 4]
Using an autoclave with an internal volume of 100 L and a stirrer and a jacket and capable of temperature control as a reactor, 5,920 g of 1,3-butadiene, 2,080 g of styrene, and cyclohexane from which impurities have been removed in advance were used. 52,000 g, 7.18 g of piperidine (Pp), 8 g of tetrahydrofuran (THF) and 6 g of 2,2-bis (2-oxolanyl) propane (BOP) as polar substances were put into the reactor, and the temperature inside the reactor was adjusted. It was maintained at the polymerization initiation temperature shown in Table 1.
2,2-Dimethoxy-1- (3-Methoxysilylpropyl) -1-aza-2-silacyclopentane (X-1), 2-methoxy-2-methyl-1- (3-Methoxysilylpropyl) The conjugated diene polymer (Sample D-) after the drying treatment was carried out in the same manner as in Example 2 except that the amount of silylpropyl) -1-aza-2-silacyclopentane (X-2) was changed and the amount of addition was changed. A conjugated diene polymer (Sample D-2) after 1) and coupling was prepared. Table 1 shows the reaction temperature peak, the ratio of polymer chains having nitrogen atoms obtained from Sample D-1, and the coupling rate of the conjugated diene-based polymer after coupling obtained from Sample D-2.

[Example 5]
Using an autoclave with an internal volume of 100 L and a stirrer and a jacket and capable of temperature control as a reactor, 5,920 g of 1,3-butadiene, 2,080 g of styrene, and cyclohexane from which impurities have been removed in advance were used. 52,000 g, 6.12 g of piperidine (Pp), 8 g of tetrahydrofuran (THF) and 5.12 g of 2,2-bis (2-oxolanyl) propane (BOP) as polar substances were placed in the reactor and placed in the reactor. The temperature was maintained at the polymerization initiation temperature shown in Table 1.
As a polymerization initiator, 5.12 g of n-butyllithium was supplied to the reactor.
After the start of the polymerization reaction, the temperature inside the reactor began to rise due to the heat generated by the polymerization. Polymerization was carried out while cooling by flowing water through the jacket so that the temperature in the final reactor was 75 to 80 ° C.
Polymerization was carried out in the same manner as in Example 2 except that the above cooling was performed, and the conjugated diene polymer after drying treatment (sample E-1) and the conjugated diene polymer after coupling (sample E-2). )created. Table 1 shows the reaction temperature peak, the ratio of the polymerized chains having nitrogen atoms obtained from Sample E-1, and the coupling ratio of the conjugated diene-based polymer after coupling obtained from Sample E-2.

[Example 6]
The same as in Example 5 except that the temperature inside the reactor was maintained at 38 ° C. and the polymerization was carried out while cooling by flowing water through the jacket so that the final temperature inside the reactor was 80 to 85 ° C. , A conjugated diene polymer after drying treatment (Sample F-1) and a conjugated diene polymer after coupling (Sample F-2) were prepared. Table 1 shows the reaction temperature peak, the ratio of polymer chains having nitrogen atoms determined from sample F-1, and the coupling ratio of the conjugated diene polymer after coupling determined from sample F-2.

[Example 7]
Using a temperature-controllable autoclave equipped with a stirrer and a jacket as a reactor with an internal volume of 100 L, 5,920 g of 1,3-butadiene, 2,080 g of styrene, and cyclohexane from which impurities have been removed in advance were used. 52,000 g, 8.32 g of hexamethyleneimine (HMI), 8 g of tetrahydrofuran (THF) and 6 g of 2,2-bis (2-oxolanyl) propane (BOP) as polar substances were placed in the reactor and placed in the reactor. The temperature was maintained at the polymerization initiation temperature shown in Table 1.
The conjugated diene polymer (Sample G-1) after the drying treatment and the conjugated diene polymer (Sample G-2) after the coupling were prepared in the same manner as in Example 3 except that the piperidine was changed to hexamethyleneimine. Made. Table 1 shows the reaction temperature peak, the ratio of the polymerized chains having a nitrogen atom obtained from the sample G-1, and the coupling rate of the conjugated diene-based polymer after the coupling obtained from the sample G-2.

[Example 8]
Using a temperature-controllable autoclave equipped with a stirrer and a jacket as a reactor with an internal volume of 100 L, 5,920 g of 1,3-butadiene, 2,080 g of styrene, and cyclohexane from which impurities have been removed in advance were used. 52,000 g, 9.23 g of 3,5-dimethylpiperidine (DMP), 8 g of tetrahydrofuran (THF) and 6 g of 2,2-bis (2-oxolanyl) propane (BOP) as polar substances were placed in the reactor. The temperature inside the reactor was maintained at the polymerization start temperature shown in Table 1.
The conjugated diene polymer after drying treatment (sample H-1) and the conjugated diene polymer after coupling (sample (H)) in the same manner as in Example 3 except that piperidine was changed to 3,5-dimethylpiperidine. -2) was prepared. The reaction temperature peak, the ratio of polymer chains having nitrogen atoms obtained from sample H-1, and the coupling ratio of the conjugated diene polymer after coupling determined from sample H-2 are shown in Table 1. It was shown to.

[Comparative Examples 1 to 3]
Polymerization was carried out in the same manner as in Example 2 except that the polymerization start temperature was changed as shown in Table 1.
Table 1 shows the reaction temperature peak, the ratio of the polymerized chains having a nitrogen atom, and the coupling ratio, respectively.

[Examples 9 to 15, Comparative Examples 4 to 6]
The samples (Samples B to K) shown in Table 1 were used as raw material rubbers, and modified conjugated diene-based polymer compositions containing the respective raw material rubbers were obtained according to the formulation shown below.

Coupling conjugated diene polymer (Samples B-2 to K-2): 100.0 parts by mass Silica (Ebonic Degusa, Ultrasil 7000GR): 75.0 parts by mass Carbon Black (Tokai Carbon, Inc., Seast KH (N339)): 5.0 parts by mass silane coupling agent (Ebonic Degusa, Si75): 6.0 parts by mass S-RAE oil (Japan Energy, JOMO process NC140): 30.0 Mass wax (manufactured by Ouchi Shinko Kagaku Co., Ltd., Sannock N): 1.5 mass Zinc flower: 2.5 mass Steeric acid: 2.0 mass Anti-aging agent (N-isoflopyl-N'-phenyl-p) -Phenylenediamine): 2.0 parts by mass Sulfur: 1.8 parts by mass Refrigeration accelerator (N-cyclohexyl-2-benzothiadyl sulfine amide): 1.7 parts by mass Refrigeration accelerator (diphenylguanidine): 2 .0 parts by mass Total: 229.5 parts by mass

The above materials were kneaded by the following method to obtain a modified conjugated diene polymer composition.
Using a closed kneader equipped with a temperature control device (content capacity 0.3 L), as the first stage kneading, the raw material rubber (Sample B-2 ~ K-2), filler (silica, carbon black), silane coupling agent, process oil (S-RAE oil, wax), zinc oxide, and stearic acid were kneaded. At this time, the temperature of the closed mixer was controlled, and the discharge temperature (combination) was 155 to 160 ° C. to obtain a modified conjugated diene polymer composition.
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. Also in this case, the discharge temperature (blending) was adjusted to 155 to 160 ° C. by controlling the temperature of the mixer.
After cooling, as the third stage kneading, sulfur and a vulcanization accelerator were added and kneaded in an oven roll set at 70 ° C. Then, it was molded and vulcanized in a vulcanization press at 160 ° C. for 20 minutes.
After vulcanization, the physical characteristics of the modified conjugated diene polymer composition were measured. The results of physical property measurement are shown in Table 2.
The physical characteristics of the modified conjugated diene polymer composition, which is a vulcanized product, after vulcanization as described above were measured by the following method.

(1) Composition Mooney Viscosity Using a Mooney viscometer, measure the viscosity after preheating at 130 ° C. for 1 minute and then rotating the rotor at 2 rpm for 4 minutes according to JIS K6300-1. Then, the result of Comparative Example 4 was set as 100 and indexed. The smaller the value, the better the workability.

(2) Tensile characteristics 300% modulus, elongation, measured according to the tensile test method of JISK6251, and the result of Comparative Example 4 was indexed as 100.

(3) Viscoelasticity parameters The viscoelasticity parameters were measured in the torsion mode using a viscoelasticity tester (ARES) manufactured by Leometrics Scientific Co., Ltd.
Each measured value was indexed with 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 skid performance.
The larger the value, the better the wet skid performance.
Further, tan δ measured at a frequency of 10 Hz and a strain of 3% at 50 ° C. was used as an index of fuel saving characteristics. The smaller the value of tan δ, the lower the hysteresis loss, and the better the fuel saving performance.

(4) Abrasion resistance Using an Akron abrasion tester (manufactured by Yasuda Seiki Seisakusho), the amount of abrasion at a load of 44.1N and 1000 rotations was measured according to JISK6264-2, and Comparative Example 4 was indexed as 100. .. The larger the index, the better the wear resistance.

As shown in Table 2, the conjugated diene-based polymer compositions of Examples 9 to 15 have a lower tan δ at 50 ° C. and less hysteresis loss as compared with the conjugated diene-based polymer compositions of Comparative Examples 4 to 6. It was confirmed that the low rolling resistance of the tire was realized, the tan δ at 0 ° C was high, and the wet skid resistance was excellent.
Furthermore, it was confirmed that it had practically sufficient workability (mixture Mooney viscosity), wear resistance, 300% modulus, and elongation.

[Example 16]
An autoclave having an internal volume of 100 L and equipped with a stirrer and a jacket and capable of temperature control was used as a reactor, and impurities were removed in advance. Initially charged 1,3-butadiene was 5,200 g, and styrene was 1,200 g. 52,000 g of cyclohexane, 7.9 g of piperidine (Pp), 16 g of tetrahydrofuran (THF) and 0.14 g of 2,2-bis (2-oxolanyl) propane (BOP) as polar substances were placed in the reactor. The temperature inside the reactor was maintained at 28 ° C.
As a polymerization initiator, 5 g of n-butyllithium was supplied to the reactor.
After the start of the polymerization reaction, the temperature inside the reactor began to rise due to the heat generated by the polymerization, and the temperature peak inside the reactor reached 70 ° C. One minute after reaching this reaction temperature peak, 1,600 g of 1,3-butadiene was added into the reactor. Finally, the reaction temperature reached 75 ° C. A small amount of the polymer solution was collected 2 minutes after the final reaction temperature peak (conjugated diene polymer after drying treatment (sample L-1)), and 3 minutes after the reaction temperature peak was reached after the small amount was collected, the reactor was used. 5.4 g of 2,2-dimethoxy-1- (3-Urimethoxysilylpropyl) -1-aza-2-silacyclopentane (X-1) was added to the mixture, and a coupling reaction was carried out for 10 minutes. In this polymer solution, 30 g of n-octadecyl-3- (3,5-di-t-butyl-4-hydrooxyphenyl) -propionate as an antioxidant and 4,6-bis (octylthiomethyl)- After adding 12 g of o-cresol, the solvent was removed by steam steam ripping, and the mixture was dried by a dryer to obtain a conjugated diene polymer (Sample L-2) after coupling.
As a result of analyzing Sample L-1, the amount of bound styrene was 14.2% by mass and the amount of bound butadiene was 86% by mass. The vinyl bond amount (1,2-bond amount) of the microstructure of the butadiene portion calculated from the measurement result using the infrared spectrophotometer according to the Hampton method was 29.7%. The proportion of polymerized chains having a nitrogen atom was 91%. As a result of measuring the coupling rate with the sample L-2, the coupling rate was 78%.

[Comparative Example 7]
Polymerization was carried out in the same manner as in Example 16 except that the polymerization start temperature was changed to the temperature shown in Table 3.
Table 3 shows the reaction temperature peak, the ratio of polymerized chains having nitrogen atoms, and the coupling rate.

[Example 17, Comparative Example 8]
Using the samples (Samples L-2 and M-2) shown in Table 3 as raw material rubbers, a conjugated diene polymer composition containing each raw material rubber was obtained according to the formulation shown below.

Coupling conjugated diene polymer (Samples L-2, M-2): 100.0 parts by mass Silica (Ebonic Degusa, Ultrasil 7000GR): 75.0 parts by mass Carbon Black (Tokai Carbon) , Seast KH (N339)): 5.0 parts by mass silane coupling agent (Ebonic Degusa, Si75): 6.0 parts by mass S-RAE oil (Japan Energy, JOMO process NC140): 30 .0 parts by mass wax (manufactured by Ouchi Shinko Kagaku Co., Ltd., Sannock N): 1.5 parts by mass Zinc flower: 2.5 parts by mass Stealic acid: 2.0 parts by mass Anti-aging agent (N-isoflopyl-N'-phenyl) -P-Phenylenideamine): 2.0 parts by mass Sulfur: 1.8 parts by mass Refrigeration accelerator (N-cyclohexyl-2-benzothiazil sulfinamide): 1.7 parts by mass Refining accelerator (diphenylguanidine) : 2.0 parts by mass Total: 229.5 parts by mass

The above materials were kneaded by the following method to obtain a conjugated diene polymer composition.
Using a closed kneader (content capacity 0.3L) equipped with a temperature control device, as the first stage kneading, the raw material rubber (sample L-2, sample L-2, under the conditions of a filling rate of 65% and a rotor rotation speed of 50/57 rpm). M-2), filler (silica, carbon black), organic silane coupling agent, process oil (S-RAE oil, wax), zinc oxide, and stearic acid were kneaded. At this time, the temperature of the closed mixer was controlled, and the discharge temperature (combination) was 155 to 160 ° C. to obtain a conjugated diene polymer composition.
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. Also in this case, the discharge temperature (blending) was adjusted to 155 to 160 ° C. by controlling the temperature of the mixer.
After cooling, as the third stage kneading, sulfur and a vulcanization accelerator were added and kneaded in an oven roll set at 70 ° C. Then, it was molded and vulcanized in a vulcanization press at 160 ° C. for 20 minutes.
After vulcanization, the physical characteristics of the modified conjugated diene polymer composition were measured. The results of physical property measurement are shown in Table 4.
The physical properties of the conjugated diene polymer composition, which is a vulcanized product, after vulcanization as described above were measured by the following method.

(1) Composition Mooney Viscosity Using a Mooney viscometer, measure the viscosity after preheating at 130 ° C. for 1 minute and then rotating the rotor at 2 rpm for 4 minutes according to JIS K6300-1. Then, the result of Comparative Example 7 was set as 100 and indexed. The smaller the value, the better the workability.

(2) Tensile characteristics 300% modulus, elongation, measured according to the tensile test method of JISK6251, and the result of Comparative Example 7 was indexed as 100.

(3) Viscoelasticity parameters The viscoelasticity parameters were measured in the torsion mode using a viscoelasticity tester (ARES) manufactured by Leometrics Scientific Co., Ltd.
Each measured value was indexed with Comparative Example 7 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 skid performance.
The larger the value, the better the wet skid performance.
Further, tan δ measured at a frequency of 10 Hz and a strain of 3% at 50 ° C. was used as an index of fuel saving characteristics. The smaller the value, the better the fuel efficiency.

(4) Abrasion resistance Using an Akron abrasion tester (manufactured by Yasuda Seiki Seisakusho), the amount of abrasion at a load of 44.1N and 1000 rotations was measured according to JISK6264-2, and the amount of abrasion was indexed with Comparative Example 7 as 100. .. The larger the index, the better the wear resistance.

As shown in Table 4, the conjugated diene polymer composition of Example 17 has a lower tan δ at 50 ° C., less hysteresis loss, and lower rolling resistance of the tire, as compared with the composition of Comparative Example 7. At the same time, it was confirmed that the tan δ at 0 ° C. was high and the wet skid resistance was excellent.
Furthermore, it was confirmed that it had practically sufficient workability (mixture Mooney viscosity), wear resistance, 300% modulus, and elongation.

The method for producing a conjugated diene-based polymer and a conjugated diene-based polymer of the present invention is industrially used as a technique for producing a rubber-like polymer constituting a rubber composition suitable for tire rubber, anti-vibration rubber, footwear, and the like. May be available.

Claims (4)

After supplying the conjugated diene monomer and the compound represented by the following formula (1) or (2) into the reactor, an organic lithium compound is added as a polymerization initiator to polymerize the conjugated diene monomer. Has a polymerization step to
The ratio of the polymerized chains having the structure derived from the compound represented by the formula (1) or (2) at the molecular end obtained by the polymerization step is 70 to 98% by mass.
A method for producing a conjugated diene-based polymer, wherein in the polymerization step, the solution temperature at the start of polymerization is in the range of 10 to 40 ° C., and the reaction peak temperature is in the range of 75 to 85 ° C.

[In the formula (1), R ¹ and R ² may be the same or different, and have an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 14 carbon atoms, and 6 to 6 carbon atoms. It is one selected from the group consisting of 20 aralkyl groups. R ¹ and R ² may be bonded to form a cyclic structure together with adjacent nitrogen atoms, in which case R ¹ and R ² have a total carbon number of 4 to 1.
The hydrocarbon group of 2 may have an unsaturated bond or a branched structure. ]

[In the formula (2), R ¹ and R ² are the same as R ¹ and R ² in Formula (1), R ³ is an alkylene group having 1 to 20 carbon atoms, or the formula (3) - ( It is one of 5). However, when the R ³ is an alkylene group having 1 to 20 carbon atoms, X is any of Cl, Br, and I, and the R ³ is any of the following formulas (3) to (5). X is a hydrogen atom. ]

In the polymerization step, the solution temperature at the start of polymerization was set in the range of 20 to 35 ° C, and the reaction peak temperature was set in the range of 75 to 80 ° C.
The ratio of polymerized chains having a structure derived from the compound represented by the formula (1) or (2) at the end of the molecule is 8
The method for producing a conjugated diene-based polymer according to claim 1, which is 0 to 98% by mass. A coupling step of reacting a polymer chain having a structure derived from a compound represented by the formula (1) or (2) at the molecular terminal obtained by the polymerization step with a coupling agent represented by the following formula (6). Have more
The method for producing a conjugated diene polymer according to claim 1 or 2, wherein the coupling agent has a coupling ratio of 70 to 95% by mass.

[In the formula (6), R ^{4 to} R ⁷ each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and R ⁸ has 3 to 10 carbon atoms. Represents an alkylene group, R ⁹ represents an alkylene group having 1 to 20 carbon atoms, m is an integer of 1 or 2, and n is an integer of 2 or 3. ] The method for producing a conjugated diene polymer according to claim 3, wherein the coupling ratio is 75% to 95%.