JP2020196803A - Method for producing modified conjugated diene polymer, modified conjugated diene polymer, polymer composition, crosslinked product and tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a modified conjugated diene polymer capable of obtaining a rubber composition having an appropriately high Mooney viscosity and good processability, and capable of obtaining a crosslinked product exhibiting excellent low heat generation. A conjugated diene having an active terminal is obtained by polymerizing a monomer containing a conjugated diene compound in the presence of a metal amide compound obtained by mixing an alkali metal compound or an alkaline earth metal compound with a compound (A). A modified conjugated diene polymer is produced by a method including a step of obtaining a system polymer and a step of reacting a conjugated diene polymer having an active terminal with a compound represented by the formula (1). (A) A compound having at least one nitrogen-containing group selected from the group consisting of a protected secondary amino group and a tertiary amino group, and one secondary amino group. [Selection diagram] None

Description

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

Conjugated diene-based polymers obtained by polymerization using conjugated diene compounds have good properties such as heat resistance, abrasion resistance, mechanical strength, and moldability. Therefore, pneumatic tires, anti-vibration rubbers, etc. Widely used in various industrial products such as hoses. For example, as a rubber composition used for treads, sidewalls, etc. of pneumatic tires, in order to improve the durability and abrasion resistance of the product, a reinforcing agent such as carbon black or silica is used together with a conjugated diene polymer. It is known to be incorporated into compositions. Further, in order to enhance the affinity between the conjugated diene polymer and the reinforcing agent, a rubber composition is prepared using a modified conjugated diene polymer in which one end or both ends of the conjugated diene polymer are modified with a nitrogen-containing compound. It is manufactured (see, for example, Patent Document 1 and Patent Document 2).

Patent Document 1 describes the processability of a polymer composition by reacting a hydrocarbyloxysilane compound having a total of two or more imino groups with a conjugated diene-based polymer having an active terminal to modify the polymer terminal. It is disclosed that a crosslinked rubber can be obtained in a good manner and has excellent low heat generation. Patent Document 2 contains a modified conjugated diene polymer terminal-modified with a hydrocarbyloxysilane compound having one imino group in a specific ratio, and contains hydrous silicic acid in which BET and CTAB are each within a predetermined range. It is disclosed that low heat generation, wet performance, processability and the like are improved by using the rubber composition. Further, Patent Documents 1 and 2 describe that the starting end of a conjugated diene polymer is modified by using a lithium amide compound as a polymerization initiator.

International Publication No. 2017/221943 Japanese Unexamined Patent Publication No. 2001-131340

As one of the methods for improving fuel efficiency, there is a technique for modifying both ends of a conjugated diene polymer. However, the modified conjugated diene polymer in which both ends of the conjugated diene polymer are modified has a high Mooney viscosity, and there is a concern that the processability of the rubber composition may be lowered. Further, in recent years, due to the improvement of consumers' awareness of environmental conditions and energy saving, a material having better fuel efficiency (low heat generation) than before is desired as a rubber for pneumatic tires.

The present invention has been made in view of the above problems, and a rubber composition having an appropriately high Mooney viscosity and good processability can be obtained, and a crosslinked product exhibiting excellent low heat generation can be obtained. A main object of the present invention is to provide a method for producing a modified conjugated diene-based polymer and a modified conjugated diene-based polymer obtained by using the production method.

The present invention provides the following methods for producing a modified conjugated diene polymer, a modified conjugated diene polymer, a polymer composition, a crosslinked product, and a tire.

（式（１）中、Ｒ^１及びＲ^２は、それぞれ独立に炭素数１〜１８のヒドロカルビル基であり、Ｒ^３は、炭素数１〜２０のアルカンジイル基である。Ｒ^４及びＲ^５は、それぞれ独立に水素原子、炭素数１〜１８のヒドロカルビル基、若しくはヒドロカルビル基の炭素−炭素結合間に−ＮＲ^ａ−（ただし、Ｒ^ａはヒドロカルビル基）、−Ｎ＝及び−Ｏ−の少なくともいずれかを有する炭素数２〜１８の１価の基であるか、又は、Ｒ^４及びＲ^５が互いに合わせられこれらが結合する炭素原子と共に構成される環構造を表す。ただし、Ｒ^４及びＲ^５は同時に水素原子にならない。ｎは１〜３の整数である。ｎが１の場合、式中の複数のＲ^１は、互いに同じでも異なっていてもよく、ｎが２又は３の場合、式中の複数のＲ^２は、互いに同じでも異なっていてもよい。） [1] A monomer containing a conjugated diene compound is polymerized in the presence of a metal amide compound obtained by mixing an alkali metal compound or an alkaline earth metal compound with the following compound (A) to obtain a conjugate having an active terminal. A method for producing a modified conjugated diene polymer, which comprises a step of obtaining a diene polymer and a step of reacting the conjugated diene polymer having an active terminal with a compound represented by the following formula (1). ..
(A) A compound having at least one nitrogen-containing group selected from the group consisting of a protected secondary amino group and a tertiary amino group, and one secondary amino group.

(In the formula (1), R ¹ and R ² are independently hydrocarbyl groups having 1 to 18 carbon atoms, R ³ is an alkanediyl group having 1 to 20 carbon atoms, and R ⁴ and R ⁵ are. , Independently hydrogen atom, hydrocarbyl group having 1 to 18 carbon atoms, or -NR ^a- (where ^Ra is a hydrocarbyl group), -N = and -O- between carbon-carbon bonds of the hydrocarbyl group. It represents a ring structure in which it is a monovalent group having 2 to 18 carbon atoms, or R ⁴ and R ⁵ are combined with each other and composed of carbon atoms to which they are bonded, except that R ⁴ and R ^{5 are formed.} is not not .n is an integer of 1 to 3 simultaneously hydrogen atom when .n is 1, a plurality of R ¹ in the formula may be the same or different from each other when n is 2 or 3, wherein a plurality of R ² in may be the same or different from each other.)

（式（４）中、Ｒ^１は炭素数１〜１８のヒドロカルビル基であり、Ｂ^１は、炭素数１〜２０のヒドロカルビルオキシ基、又は、２級アミノ基、保護された２級アミノ基及び３級アミノ基よりなる群から選択される少なくとも一種の窒素含有基を末端に２個以上有する共役ジエン系重合体鎖である。Ｒ^３は、炭素数１〜２０のアルカンジイル基である。Ｒ^４及びＲ^５は、それぞれ独立に水素原子、炭素数１〜１８のヒドロカルビル基、若しくはヒドロカルビル基の炭素−炭素結合間に−ＮＲ^ａ−（ただし、Ｒ^ａはヒドロカルビル基）、−Ｎ＝及び−Ｏ−の少なくともいずれかを有する炭素数２〜１８の１価の基であるか、又は、Ｒ^４及びＲ^５が互いに合わせられこれらが結合する炭素原子と共に構成される環構造を表す。ただし、Ｒ^４及びＲ^５は同時に水素原子にならない。Ｐｏｌｙは、２級アミノ基、保護された２級アミノ基及び３級アミノ基よりなる群から選択される少なくとも一種の窒素含有基を末端に２個以上有する共役ジエン系重合体鎖である。ｎは１〜３の整数である。ｎが１の場合、式中の複数のＲ^１は、互いに同じでも異なっていてもよく、ｎが２又は３の場合、式中の複数のＢ^１は、互いに同じでも異なっていてもよい。） [2] A modified conjugated diene-based polymer represented by the following formula (4).

In the formula (4), R ¹ is a hydrocarbyl group having 1 to 18 carbon atoms, and B ¹ is a hydrocarbyloxy group having 1 to 20 carbon atoms, a secondary amino group, a protected secondary amino group and a group. It is a conjugated diene-based polymer chain having at least two or more nitrogen-containing groups selected from the group consisting of tertiary amino groups at the end. R ³ is an alcandiyl group having 1 to 20 carbon atoms. ⁴ and R ⁵ are independently hydrogen atoms, hydrocarbyl groups having 1 to 18 carbon atoms, or -NR ^a- (where ^Ra is a hydrocarbyl group), -N = and-between carbon-carbon bonds of the hydrocarbyl group. Represents a ring structure that is a monovalent group of 2 to 18 carbon atoms with at least one of O-, or is composed of carbon atoms in which R ⁴ and R ⁵ are combined and bonded together. R ⁴ and R ⁵ do not become hydrogen atoms at the same time. Poly ends with two at least one nitrogen-containing group selected from the group consisting of a secondary amino group, a protected secondary amino group and a tertiary amino group. The conjugated diene polymer chain having the above. N is an integer of 1 to 3. When n is ¹ , a plurality of R 1s in the formula may be the same or different from each other, and n is 2 or 3. for multiple B ¹ in the formula may be the same or different from each other.)

[3] A polymer composition containing the modified conjugated diene polymer obtained by the production method of the above [1], or the modified conjugated diene polymer of the above [2], silica, and a cross-linking agent.
[4] A crosslinked product obtained by cross-linking the polymer composition of the above [3].
[5] A tire in which one or both of a tread and a sidewall is formed by using the polymer composition of the above [3].

According to the present invention, a modified conjugated diene polymer having an appropriately high Mooney viscosity can be obtained. By using such a modified conjugated diene polymer, a rubber composition having excellent processability can be obtained. Further, according to the present invention, it is possible to obtain a crosslinked rubber excellent in low heat generation while making the rubber composition excellent in processability.

Hereinafter, matters related to the aspects of the present invention will be described in detail. The modified conjugated diene polymer of the present invention is produced by a method including the following polymerization step and modification step.

<Polymerization process>
This step is a step of polymerizing a monomer containing a conjugated diene compound to obtain a conjugated diene-based polymer having an active terminal. Examples of the conjugated diene compound used for polymerization include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 1,3-heptadiene, and 2, Examples thereof include −phenyl-1,3-butadiene, 3-methyl-1,3-pentadiene, 2-chloro-1,3-butadiene and the like. Among these, at least one of 1,3-butadiene, isoprene and 2,3-dimethyl-1,3-butadiene is preferably used, and more preferably 1,3-butadiene is contained.

The conjugated diene-based polymer may be a homopolymer of the conjugated diene compound, but from the viewpoint of increasing the strength of the rubber, it is preferably a copolymer of the conjugated diene compound and the aromatic vinyl compound. Examples of the aromatic vinyl compound used for polymerization include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, and vinylethylbenzene. , Divinylbenzene, trivinylbenzene, divinylnaphthalene, t-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl) dimethylaminoethyl ether, N, N-dimethylaminoethylstyrene, N, N-dimethylaminomethylstyrene, 2-Ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2-t-butylstyrene, 3-t-butylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, vinylxylene, Examples thereof include vinylnaphthalene, vinylpyridine, diphenylethylene, tertiary amino group-containing diphenylethylene (for example, 1- (4-N, N-dimethylaminophenyl) -1-phenylethylene, etc.). As the aromatic vinyl compound, it is preferable to use at least one of styrene and α-methylstyrene.

When the conjugated diene polymer is a copolymer of a conjugated diene compound and an aromatic vinyl compound, it is obtained by using 1,3-butadiene and styrene as monomers because of its high living property in anionic polymerization. It is preferably a polymer to be obtained. This copolymer preferably has a random copolymer moiety in which the distribution of the conjugated diene compound and the aromatic vinyl compound is irregular. Further, the copolymer of the conjugated diene compound and the aromatic vinyl compound may further have a block portion composed of the conjugated diene compound or the aromatic vinyl compound.

When the conjugated diene-based polymer is a copolymer of a conjugated diene compound and an aromatic vinyl compound, the ratio of the aromatic vinyl compound used (that is, the ratio of structural units derived from the aromatic vinyl compound in the polymer). ) Shall be 3 to 55 with respect to the total amount of the conjugated diene compound and the aromatic vinyl compound used for the polymerization from the viewpoint of improving the balance between the low hysteresis loss property of the obtained crosslinked polymer and the wet skid resistance. It is preferably mass%, more preferably 5-50 mass%. The ratio of structural units derived from the aromatic vinyl compound in the polymer (hereinafter, also referred to as “bonded styrene content”) is a value measured by ¹ H-NMR. As the conjugated diene compound and the aromatic vinyl compound, one type may be used alone, or two or more types may be used in combination.

In the above polymerization, a compound different from the conjugated diene compound and the aromatic vinyl compound (hereinafter, also referred to as “another monomer”) may be used as the monomer. Examples of other monomers include acrylonitrile, methyl (meth) acrylate, ethyl (meth) acrylate and the like. The ratio of the other monomers used is preferably 10% by mass or less, more preferably 5% by mass or less, based on the total amount of the monomers used for the polymerization.

As the polymerization method to be used, any of a solution polymerization method, a gas phase polymerization method and a bulk polymerization method may be used, but the solution polymerization method is particularly preferable. Further, as the polymerization type, either a batch type or a continuous type may be used. When the solution polymerization method is used, as an example of a specific polymerization method, a monomer containing a conjugated diene compound is polymerized in an organic solvent in the presence of a polymerization initiator and, if necessary, a randomizer. There is a way to do it.

The above polymerization reaction is selected from the group consisting of an alkali metal compound or an alkaline earth metal compound (hereinafter, also referred to as “metal compound”) as a polymerization initiator, and protected secondary amino groups and tertiary amino groups. A compound having at least one nitrogen-containing group and one secondary amino group (hereinafter, also referred to as “(A) compound”) is used, and these metal compounds and the (A) compound are mixed and obtained. This is done in the presence of the resulting metal amide compound. By polymerizing the monomer in the presence of a mixture of the metal compound and the compound (A), a nitrogen-containing group derived from the compound (A) can be introduced into the polymerization initiation terminal of the conjugated diene polymer.

Specific examples of the metal compound include, for example, alkyllithium such as methyllithium, ethyllithium, n-propyllithium, n-butyllithium, sec-butyllithium and t-butyllithium, 1,4-dilithiobutane, phenyllithium and stillbenlithium. , Naftyl Lithium, 1,3-bis (1-lithio-1,3-dimethylpentyl) benzene, 1,3-phenylenebis (3-methyl-1-phenylpentylidene) dilithium, naphthyl sodium, naphthyl potassium, di- Examples thereof include n-butylmagnesium, di-n-hexylmagnesium, ethoxypotassium, calcium stearate and the like. Of these, lithium compounds are preferred. The ratio of the metal compound used (the total amount when two or more kinds are used) is preferably 0.2 to 20 mmol with respect to 100 g of the monomer used for the polymerization.

The compound (A) is a compound having at least one group selected from the group consisting of a protected secondary amino group and a tertiary amino group in total and one secondary amino group. Good. In the protected secondary amino group, the protecting group is a functional group that keeps the amino group as an inactive functional group with respect to the polymerization initiator, and is preferably a silyl protecting group. Here, the silyl protecting group is a group in which each of the three hydrogen atoms of "-SiH ₃ " is substituted with a hydrocarbyl group, and specific examples thereof include, for example, a trimethylsilyl group, a triethylsilyl group, and tert-butyldimethylsilyl. Examples include a group, a triisopropylsilyl group, and a tert-butyldiphenylsilyl group. The compound (A) has a protected secondary amino group and one secondary in that the dispersibility of silica can be sufficiently increased and a modified conjugated diene-based polymer having excellent low heat generation property can be obtained. It is preferably a compound having an amino group.

（式（２）及び式（３）中、Ａ^１、Ａ^２及びＡ^３は、それぞれ独立に、シリル保護基又はヒドロカルビル基である。Ｒ^５、Ｒ^６、Ｒ^７、Ｒ^８、Ｒ^９及びＲ^１０は、それぞれ独立にヒドロカルビレン基である。） The compound (A) may be either a chain compound or a cyclic compound, but is preferably a cyclic compound, and more preferably a heterocyclic amine. The compound (A) is particularly preferably at least one selected from the group consisting of the compound represented by the following formula (2) and the compound represented by the following formula (3).

(In formulas (2) and (3), A ¹ , A ² and A ³ are independently silyl protecting groups or hydrocarbyl groups, respectively. R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ is an independent hydrocarbylene group.)

Regarding A ¹ , A ² and A ³ of the above formula (2) and formula (3), examples of the hydrocarbyl group include a linear or branched alkyl group, an aryl group and an aralkyl group. The number of carbon atoms of the hydrocarbyl group is preferably 1 to 20, and more preferably 3 to 10.
A ¹ , A ² and A ³ are preferably silyl protecting groups in that the rolling resistance (low heat generation) of the obtained vulcanized rubber can be improved.
The hydrocarbylene groups of R ^{5 to} R ¹⁰ are preferably linear or branched alkanediyl groups. The number of carbon atoms of the hydrocarbylene group is preferably 1 to 10, and more preferably 1 to 3.

Specific examples of the compound (A) include compounds represented by the following formulas (a-1) to (a-9).

When the polymerization is carried out in the presence of the metal amide compound obtained by mixing the metal compound and the compound (A), the metal compound and the compound (A) are mixed in advance, and the mixture is placed in the polymerization system. It may be added and polymerized. Alternatively, the metal compound and the compound (A) may be added separately or simultaneously to the polymerization system, and both may be mixed and polymerized in the polymerization system. In any of these cases, it is included in the embodiment of "polymerizing a monomer containing a conjugated diene compound in the presence of a metal amide compound obtained by mixing an alkali metal compound or an alkaline earth metal compound with the compound (A)". ..

The amount of the compound (A) used with respect to the metal compound can be appropriately set according to the type of the metal compound used. For example, when metallic lithium is used as the metal compound, the amount of the compound (A) used is preferably in the range of 0.1 to 1.8 mol with respect to 1 mol of the entire metallic lithium used for the polymerization. .. From the viewpoint of suppressing a decrease in processability when the rubber composition is obtained, the amount of the compound (A) used is preferably less than 1 mol, preferably less than 1 mol, based on 1 mol of the total amount of metallic lithium used for polymerization. It is more preferably .98 mol or less, and further preferably 0.95 mol or less. Further, from the viewpoint of sufficiently obtaining the effect of improving the fuel efficiency performance, the amount of the compound (A) used is preferably 0.2 mol or more with respect to 1 mol of the entire metallic lithium used for the polymerization. More preferably, it is 0.3 mol or more. As the compound (A), one type can be used alone or two or more types can be used in combination.

The randomizer can be used for the purpose of adjusting the vinyl bond content, which represents the vinyl bond content in the polymer. Examples of randomizers include dimethoxybenzene, tetrahydrofuran, dimethoxyethane, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, 2,2-di (tetrahydrofuryl) propane, 2- (2-ethoxyethoxy) -2-methylpropane, triethylamine, pyridine. , N-Methylmorpholine, tetramethylethylenediamine and the like. As the randomizer, one of these can be used alone or in combination of two or more.

The organic solvent used for the polymerization may be any organic solvent inert to the reaction, and for example, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons and the like can be used. Of these, hydrocarbons having 3 to 8 carbon atoms are preferable. Specific examples of the organic solvent used for the polymerization include propane, n-butene, isobutene, n-pentane, isopentane, n-hexane, cyclohexane, propene, 1-butene, isobutene, trans-2-butene, and the like. Sis-2-butene, 1-pentyne, 2-pentyne, 1-hexene, 2-hexene, benzene, toluene, xylene, ethylbenzene, heptane, cyclopentane, methylcyclopentane, methylcyclohexane, 1-pentene, 2-pentene, Cyclohexene and the like can be mentioned. As the organic solvent, one type can be used alone or two or more types can be used in combination.

In the case of solution polymerization, the monomer concentration in the reaction solvent is preferably 5 to 50% by mass, preferably 10 to 30% by mass, from the viewpoint of maintaining a balance between productivity and ease of polymerization control. More preferred. The temperature of the polymerization reaction is preferably −20 ° C. to 150 ° C., more preferably 0 to 120 ° C. Further, it is preferable that the polymerization reaction is carried out under a pressure sufficient to keep the monomer substantially in the liquid phase. Such a pressure can be obtained by a method such as pressurizing the inside of the reactor with a gas inert to the polymerization reaction.

By such a polymerization reaction, a nitrogen-containing group derived from the compound (A) is introduced at one end, and a conjugated diene-based polymer having an active end at the other end can be obtained. The weight average molecular weight in terms of polystyrene by the obtained conjugated diene-based polymer by gel permeation chromatography (GPC) (Mw) is preferably ^{5.0 × 10 4 ~1.0 × 10 6} . When Mw is less than 5.0 × 10 ^4, the tensile strength of the crosslinked polymer, when there is a tendency that easy low heat build-up and abrasion resistance decreases, greater than 1.0 × 10 ^6, a modified polymer The processability of the rubber composition obtained by using the product tends to decrease. Mw is more preferably 8.0 × 10 ⁴ or more, further preferably 1.0 × 10 ⁵ or more. Further, Mw is more preferably 8.0 × 10 ⁵ or less, more preferably 5.0 × 10 ⁵ or less.

For the conjugated diene polymer having an active terminal, the vinyl bond content in the butadiene unit is preferably 30 to 70% by mass, more preferably 33 to 68% by mass, and 35 to 65% by mass. Is even more preferable. If the vinyl bond content is less than 30 mol%, the grip characteristics tend to be low, and if it exceeds 70% by mass, the wear resistance of the obtained vulcanized rubber tends to be low. In the present specification, the "vinyl bond content" is a value indicating the content ratio of the structural unit having a 1,2-bond to the total structural unit of butadiene in the conjugated diene polymer, and is ¹ H-NMR. It is a value measured by.

（式（１）中、Ｒ^１及びＲ^２は、それぞれ独立に炭素数１〜１８のヒドロカルビル基であり、Ｒ^３は、炭素数１〜２０のアルカンジイル基である。Ｒ^４及びＲ^５は、それぞれ独立に水素原子、炭素数１〜１８のヒドロカルビル基、若しくはヒドロカルビル基の炭素−炭素結合間に−ＮＲ^ａ−（ただし、Ｒ^ａはヒドロカルビル基）、−Ｎ＝及び−Ｏ−の少なくともいずれかを有する炭素数２〜１８の１価の基であるか、又は、Ｒ^４及びＲ^５が互いに合わせられこれらが結合する炭素原子と共に構成される環構造を表す。ただし、Ｒ^４及びＲ^５は同時に水素原子にならない。ｎは１〜３の整数である。ｎが１の場合、式中の複数のＲ^１は、互いに同じでも異なっていてもよく、ｎが２又は３の場合、式中の複数のＲ^２は、互いに同じでも異なっていてもよい。） <Degeneration process>
In this step, the active terminal of the conjugated diene polymer obtained in the above polymerization step is reacted with the compound represented by the following formula (1) (hereinafter, also referred to as “(M) compound”). This makes it possible to obtain a modified conjugated diene-based polymer in which a group (secondary amino group) that interacts with silica is introduced at the end of polymerization.

(In the formula (1), R ¹ and R ² are independently hydrocarbyl groups having 1 to 18 carbon atoms, R ³ is an alkanediyl group having 1 to 20 carbon atoms, and R ⁴ and R ⁵ are. , Independently hydrogen atom, hydrocarbyl group having 1 to 18 carbon atoms, or -NR ^a- (where ^Ra is a hydrocarbyl group), -N = and -O- between carbon-carbon bonds of the hydrocarbyl group. It represents a ring structure in which it is a monovalent group having 2 to 18 carbon atoms, or R ⁴ and R ⁵ are combined with each other and composed of carbon atoms to which they are bonded, except that R ⁴ and R ^{5 are formed.} is not not .n is an integer of 1 to 3 simultaneously hydrogen atom when .n is 1, a plurality of R ¹ in the formula may be the same or different from each other when n is 2 or 3, wherein a plurality of R ² in may be the same or different from each other.)

In the above formula (1), examples of the hydrocarbyl group of R ¹ and R ² include an alkyl group having 1 to 18 carbon atoms, an allyl group, a cycloalkyl group having 3 to 18 carbon atoms, and an aryl group having 6 to 18 carbon atoms. Be done. Examples of the hydrocarbylene group of R ³ include an alkanediyl group having 1 to 20 carbon atoms, a cycloalkylene group having 3 to 20 carbon atoms, and an arylene group having 6 to 20 carbon atoms. R ³ is preferably a linear or branched alkanediyl group having 1 to 20 carbon atoms, and more preferably a linear alkanediyl group having 2 to 15 carbon atoms.

The hydrocarbyl groups of R ⁴ and R ⁵ include, for example, a linear or branched alkyl group having 1 to 18 carbon atoms, an allyl group, a cycloalkyl group having 3 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, and carbon. Alkyl groups of numbers 6-18 can be mentioned.
When at least one of R ⁴ and R ⁵ is a monovalent group having 2 to 18 carbon atoms having at least one of -NR ^a- , -N = and -O- between carbon-carbon bonds of the hydrocarbyl group. As a specific example thereof, a group having −NR ^a −, −N = or −O− between carbon-carbon bonds of an alkyl group having 2 to 18 carbon atoms; pyridine, pyrimidine, pyrazine, quinoline, oxane, furan, Examples thereof include a group obtained by removing one hydrogen atom from the ring portion of a saturated or unsaturated monocyclic or condensed ring such as pyran. ^Ra is preferably an alkyl group having 1 to 5 carbon atoms.
As a specific example of a ring structure in which R ⁴ and R ⁵ are combined with each other and composed of carbon atoms to which they are bonded, a ring portion has at least one of a cycloalkylidene group having 3 to 18 carbon atoms, a nitrogen atom and an oxygen atom. Examples include heterocyclic groups.
n is preferably 2 or 3 and more preferably 3 in that the effect of improving silica dispersibility can be further enhanced.

As specific examples of the compound (M), for example, the compounds represented by the following formulas (m-1) to (m-8), and the alkyl group and the alkanediyl group in the following compounds each have 1 carbon number. Examples thereof include compounds in which an alkyl group of ~ 6 is replaced with an alkanediyl group having 1 to 6 carbon atoms. As the compound (M), one type may be used alone, or two or more types may be used in combination.

The reaction between the conjugated diene polymer having an active terminal and the compound (M) can be, for example, a solution reaction. The ratio of the compound (M) used (the total amount when two or more compounds are used) is 0 with respect to 1 mol of the metal atom involved in the polymerization of the polymerization initiator from the viewpoint of sufficiently advancing the modification reaction. It is preferably 0.01 mol or more, and more preferably 0.05 mol or more. Further, the ratio of the compound (M) used is preferably less than 2.0 mol with respect to 1 mol of the metal atom involved in the polymerization of the polymerization initiator in order to avoid excessive addition of the compound (M). , More preferably less than 1.5 mol.

The temperature of the denaturation reaction is usually the same as that of the polymerization reaction, and is preferably −20 ° C. to 150 ° C., more preferably 0 to 120 ° C. When the reaction temperature is low, the viscosity of the modified polymer tends to increase, and when the reaction temperature is high, the polymerization active end is likely to be deactivated. The reaction time is preferably 1 minute to 5 hours, more preferably 2 minutes to 1 hour.

In the reaction of the conjugated diene polymer having an active terminal with the (M) compound, a denaturing agent different from the (M) compound (hereinafter, also referred to as “other denaturing agent”) or a cup together with the (M) compound. A ring agent may be used. The other modifier or coupling agent is not particularly limited as long as it is a compound capable of reacting with the active terminal of the conjugated diene polymer obtained by the above polymerization, and as a modifier or coupling agent of the conjugated diene polymer. Known compounds can be used. When other denaturing agents or coupling agents are used, the ratio of their use is 10 mol% or less based on the total amount of the denaturing agent and the coupling agent used in the denaturing reaction of the conjugated diene polymer having an active terminal. It is preferably 5 mol% or less, and more preferably 5 mol% or less.

The modified conjugated diene polymer contained in the reaction solution can be isolated by a known desolvation method such as steam stripping and a drying operation such as heat treatment. The modified conjugated diene polymer thus obtained has a structure in which the conjugated diene polymer chain is bonded to the reaction site (carbon-nitrogen double bond (C = N group), alkoxysilyl group) of the (M) compound. Have. It is considered that the C = N group has higher reactivity than the alkoxysilyl group and preferentially reacts with the active terminal of the conjugated diene polymer.

（式（４）中、Ｒ^１は炭素数１〜１８のヒドロカルビル基であり、Ｂ^１は、炭素数１〜２０のヒドロカルビルオキシ基、又は、２級アミノ基、保護された２級アミノ基及び３級アミノ基よりなる群から選択される少なくとも一種の窒素含有基を末端に２個以上有する共役ジエン系重合体鎖である。Ｒ^３は、炭素数１〜２０のアルカンジイル基である。Ｒ^４及びＲ^５は、それぞれ独立に水素原子、炭素数１〜１８のヒドロカルビル基、若しくはヒドロカルビル基の炭素−炭素結合間に−ＮＲ^ａ−（ただし、Ｒ^ａはヒドロカルビル基）、−Ｎ＝及び−Ｏ−の少なくともいずれかを有する炭素数２〜１８の１価の基であるか、又は、Ｒ^４及びＲ^５が互いに合わせられこれらが結合する炭素原子と共に構成される環構造を表す。ただし、Ｒ^４及びＲ^５は同時に水素原子にならない。Ｐｏｌｙは、２級アミノ基、保護された２級アミノ基及び３級アミノ基よりなる群から選択される少なくとも一種の窒素含有基を末端に２個以上有する共役ジエン系重合体鎖である。ｎは１〜３の整数である。ｎが１の場合、式中の複数のＲ^１は、互いに同じでも異なっていてもよく、ｎが２又は３の場合、式中の複数のＢ^１は、互いに同じでも異なっていてもよい。） The modified conjugated diene-based polymer obtained by the above polymerization step and modification step is represented by the following formula (4).

In the formula (4), R ¹ is a hydrocarbyl group having 1 to 18 carbon atoms, and B ¹ is a hydrocarbyloxy group having 1 to 20 carbon atoms, a secondary amino group, a protected secondary amino group and a group. It is a conjugated diene-based polymer chain having at least two or more nitrogen-containing groups selected from the group consisting of tertiary amino groups at the end. R ³ is an alcandiyl group having 1 to 20 carbon atoms. ⁴ and R ⁵ are independently hydrogen atoms, hydrocarbyl groups having 1 to 18 carbon atoms, or -NR ^a- (where ^Ra is a hydrocarbyl group), -N = and-between carbon-carbon bonds of the hydrocarbyl group. Represents a ring structure that is a monovalent group of 2 to 18 carbon atoms with at least one of O-, or is composed of carbon atoms in which R ⁴ and R ⁵ are combined and bonded together. R ⁴ and R ⁵ do not become hydrogen atoms at the same time. Poly ends with two at least one nitrogen-containing group selected from the group consisting of a secondary amino group, a protected secondary amino group and a tertiary amino group. The conjugated diene polymer chain having the above. N is an integer of 1 to 3. When n is ¹ , a plurality of R 1s in the formula may be the same or different from each other, and n is 2 or 3. for multiple B ¹ in the formula may be the same or different from each other.)

In the above formula (4), the description of the above formula (1) is applied to R ¹ , R ³ , R ⁴ and R ⁵ . For B ¹ , the hydrocarbyloxy group is preferably an ethoxy group or a methoxy group. The conjugated diene polymer chain of B ¹ and Poly in the above formula (4) contain a conjugated diene polymer obtained by the polymerization reaction in the above polymerization step, that is, nitrogen derived from the compound (A) at one end. It is a structure corresponding to a conjugated diene polymer having a group introduced and an active terminal at the other end.

<Polymer composition>
The polymer composition of the present invention comprises a modified conjugated diene polymer modified with the (A) compound and the (M) compound (hereinafter, also referred to as “specific modified conjugated diene polymer”), silica and crosslinked. Contains the agent. The content of the specific modified conjugated diene-based polymer in the polymer composition is preferably 10% by mass or more, more preferably 20% by mass or more, based on the total amount of the polymer composition. It is more preferably 25% by mass or more. Further, the content of the specific modified conjugated diene-based polymer in the polymer composition is preferably 50% by mass or less, more preferably 40% by mass or less, based on the total amount of the polymer composition. preferable.

Examples of silica include wet silica (hydrous silicic acid), dry silica (silicic anhydride), colloidal silica, precipitated silica, calcium silicate, aluminum silicate and the like. Of these, wet silica is particularly preferable from the viewpoint of improving the fracture characteristics and the effect of achieving both wet grip resistance and low rolling resistance. Further, it is also preferable to use high dispersion type silica from the viewpoint that the dispersibility in the polymer composition can be improved and the physical properties and processability can be improved. As for silica, one type can be used alone or two or more types can be used in combination.

In addition to silica, various reinforcing fillers such as carbon black, clay, and calcium carbonate may be blended in the polymer composition as a filler. Preferably, silica alone or a combination of carbon black and silica is used. The total amount of silica and carbon black in the polymer composition is preferably 20 to 130 parts by mass, more preferably 25 to 110 parts by mass with respect to 100 parts by mass of the total amount of the polymer components contained in the polymer composition. It is a department.

Examples of the cross-linking agent include sulfur, sulfur halides, organic peroxides, quinonedioximes, organic polyvalent amine compounds, alkylphenol resins having a methylol group, and the like, and sulfur is usually used. The blending amount of sulfur is preferably 0.1 to 5 parts by mass, and more preferably 0.5 to 3 parts by mass with respect to 100 parts by mass of the total amount of the polymer components contained in the polymer composition.

In the polymer composition, as a rubber component, in addition to the specific modified conjugated diene-based polymer, a rubber component different from the specific modified conjugated diene-based polymer (hereinafter, referred to as "other rubber component") is blended. You may. The type of other rubber components is not particularly limited, but is butadiene rubber (BR, for example, cis-1,4 bond 90% or more high cis BR, syndiotactic-1,2-polybutadiene (SPB) -containing BR, etc.), styrene butadiene. Examples thereof include rubber (SBR), natural rubber (NR), isoprene rubber (IR), styrene isoprene copolymer rubber, and butadiene isoprene copolymer rubber. Other rubber components are more preferably BR and SBR. The content of the other rubber component in the polymer composition is preferably 60% by mass or less, preferably 50% by mass or less, based on the total amount of the specific modified conjugated diene-based polymer and the other rubber component. Is more preferable.

The polymer composition may contain a process oil generally used for oil spreading the elastomer as an oil for oil spreading. The process oil is blended into the polymer composition, for example, by adding the oil directly during the rubber blending. Preferred process oils include various oils known in the art, such as aromatic oils, paraffin oils, naphthenic oils, vegetable oils, and oils with a low content of polycyclic aromatic compounds (low). PCA oil), for example, mild extraction solvate (MES), treated distillate aromatic extract (TDAE), special aromatic extraction from residual oil. Examples include substances (SRAE: special residual aromatic extract) and heavy naphthenic oils. Examples of commercially available MES, TDAE and SRAE are Shell's Catenex SNR (heavy paraffin obtained by dewaxing distillate oil with a solvent) as MES, H & R Wasag AG's Vivatec 500 as TDAE, and Japan Energy Corp as SRAE. NC140 made by. The blending amount of the process oil is preferably 10 to 100 parts by mass with respect to 100 parts by mass of the total amount of the polymer components contained in the polymer composition.

In addition to the above-mentioned components, the polymer composition includes, for example, an antiaging agent, zinc oxide, stearic acid, a softening agent, sulfur, a vulcanization accelerator, a silane coupling agent, a compatibilizer, a vulcanization aid, and processing. Various additives generally used in rubber compositions for tires, such as auxiliaries and anti-scorch agents, can be blended. These blending amounts can be appropriately selected according to various components as long as the effects of the present invention are not impaired.

In the above polymer composition, in addition to the rubber component, silica and the cross-linking agent, a kneader such as an open kneader (for example, a roll) or a closed kneader (for example, a Banbury mixer) is used to add components to be blended as needed. It can be applied to various rubber products as a crosslinked product by being kneaded using and crosslinked (vulcanized) after molding. Specifically, the crosslinked body is used for tires such as tire treads, under treads, carcasses, sidewalls, bead portions, etc .; sealing materials for packings, gaskets, weather strips, O-rings, etc .; automobiles, ships, aircraft, etc. Interior / exterior skin materials for various vehicles such as railways; Building materials; Anti-vibration rubbers for industrial machinery and equipment; Various hoses and hose covers such as diaphragms, rolls, radiator hoses, and air hoses; Power transmission belts Belts such as; linings; dust boots; materials for medical equipment; fenders; insulating materials for electric wires; other industrial products.

According to the method for producing a modified conjugated diene polymer of the present invention, a modified conjugated diene polymer having high Mooney viscosity, good shape stability, and excellent processability when made into a rubber composition can be obtained. It can be obtained while maintaining good physical properties required for tire applications such as low heat generation and wet grip resistance. Therefore, the rubber composition containing the modified conjugated diene polymer obtained by the production method is particularly suitable as a material for one or both of the tread and sidewall of the tire.

Tires can be manufactured according to conventional methods. For example, the polymer composition is mixed with a kneader, and the sheet is arranged in a predetermined position (for example, outside the carcass in the case of a sidewall) according to a conventional method and vulcanized to form a tread. Formed as rubber or sidewall rubber, pneumatic tires are obtained.

Hereinafter, the present invention will be specifically described based on Examples, but the present invention is not limited to these Examples. In addition, "part" and "%" in Examples and Comparative Examples are based on mass unless otherwise specified. The measurement method of various physical property values is shown below.

[Evaluation of polymer characteristics]
-Vinyl content (%): Measured by ¹ H-NMR at 400 MHz.
-Binding styrene content (%): Measured by ¹ H-NMR measurement at 400 MHz.
-Weight average molecular weight of polymer before denaturation reaction (peak molecular weight before denaturation reaction): After the denaturation reaction with a denaturant, gel permeation chromatography (GPC) (Viscotek TDA302 (trade name (Viscotek)) under the following measurement conditions. The GPC curve obtained using (manufactured by))) was determined in terms of polystyrene from the retention time corresponding to the peak of the peak having the smallest molecular weight.
(GPC measurement conditions)
Column: 2 product names "TSK gel HHR-H" (manufactured by Tosoh Corporation) Column temperature: 40 ° C
Mobile phase: tetrahydrofuran Flow rate: 1.0 ml / min Sample concentration: 10 mg / 20 ml
-Mooney viscosity (ML _{1 + 4} , 100 ° C.): Obtained according to JIS K6300 under the conditions of preheating 1 minute, rotor operating time 4 minutes, and temperature 100 ° C. using an L rotor.

[Characteristic evaluation of polymer composition (blended rubber)]
-Mixed Mooney Viscosity: The compounded rubber before vulcanization was used as a measurement sample, and the measurement was performed using an L rotor in accordance with JIS K6300 under the conditions of preheating 1 minute, rotor operating time 4 minutes, and temperature 100 ° C. It is displayed as an index, and the larger the value, the better the workability.
[Characteristic evaluation of vulcanized rubber]
0 ° C. tan δ: Using a vulcanized rubber as a measurement sample, measurement was performed using a dynamic spectrometer (manufactured by Leometrics, USA) under the conditions of tensile strain of 0.1%, angular velocity of 100 radians per second, and 0 ° C. .. The measurement results are displayed as an index, and the larger the value, the greater the wet skid resistance and the better.
70 ° C tan δ: Using a vulcanized rubber as a measurement sample, measurement was performed using a dynamic spectrometer (manufactured by Leometrics, USA) under the conditions of tensile dynamic strain of 0.7%, angular velocity of 100 radians per second, and 70 ° C. .. The measurement results are displayed as an index, and the larger the value, the smaller the rolling resistance and the better the low heat generation.

<Synthesis and evaluation of modified conjugated diene polymer>
[Example 1 Synthesis of modified conjugated diene polymer A and its physical properties]
An autoclave reactor having an internal volume of 5 liters substituted with nitrogen was charged with 2,500 g of cyclohexane, 50 g of tetrahydrofuran, 125 g of styrene and 365 g of 1,3-butadiene. After adjusting the temperature of the contents of the reactor to 10 ° C., 5.20 mmol of n-butyllithium and 4.20 mmol of N-trimethylsilylpiperazine were added as a polymerization initiator to initiate polymerization. The polymerization was carried out under adiabatic conditions and the maximum temperature reached 85 ° C. When the polymerization conversion rate reaches 99% (20 minutes after the start of polymerization), 10 g of 1,3-butadiene is added over 2 minutes, and then it is represented by the following formula (N-Si-1). Compound 2.60 mmol was added and the reaction was carried out for 15 minutes.
3.96 g of 2,6-di-tert-butyl-p-cresol was added to the obtained polymer solution containing the modified conjugated diene polymer. Then, the solvent was removed by steam stripping, and the mixture was dried with a heat roll adjusted to 110 ° C. to obtain a modified conjugated diene polymer A. Table 2 below shows various physical property values of the obtained modified conjugated diene polymer A.

[Synthesis of Modified Conjugated Diene Polymers B to E, P, Q and Physical Properties thereof in Examples 2 to 5 and Comparative Examples 1 and 2]
The polymerization was carried out in the same manner as the modified conjugated diene polymer A except that the types and amounts of the polymerization initiators and modifiers used were as shown in Table 1 below, and the same as that of the modified conjugated diene polymer A. The modified conjugated diene-based polymers B to E, P, and Q were obtained by removing the solvent from the solution and isolating the polymer. Table 2 below shows various physical property values of the obtained modified conjugated diene-based polymers B to E, P, and Q.

In Tables 1 and 2, the abbreviations of the compounds are as follows.
(Polymer initiator)
* 1 INI-1: N-trimethylsilyl piperazine * 2 INI-2: N- (hexyl) piperazine * 3 INI-3: 1,3-ditrimethylsilyl-1,3,5-triazinan * 4 INI-4: piperidine ( Denaturer)
* 5 to * 8 N-Si-1 to N-Si-4: Compounds represented by the following formulas (N-Si-1) to (N-Si-4).

[Manufacturing of compounded rubber and vulcanized rubber]
Using the modified conjugated diene polymer produced above, each component was compounded according to the compounding formulation shown in Table 3 below, and the compounded rubber was produced by kneading the components. Kneading was performed by the following method. Using a plast mill (contents: 250 ml) with a temperature control device, the first stage of kneading is a modified conjugated diene polymer, polybutadiene rubber, stretched oil, under the conditions of a filling rate of 72% and a rotation speed of 60 rpm. Silica, carbon black, silane coupling agent, stearic acid, anti-aging agent and zinc oxide were mixed and kneaded. Next, as the second-stage kneading, the formulation obtained above was cooled to room temperature, and then sulfur and a vulcanization accelerator were added and kneaded. This was molded and vulcanized at 160 ° C. for a predetermined time with a vulcanization press to obtain a crosslinked rubber (vulcanized rubber).
Workability, wet skid resistance and rolling resistance (low heat generation) are evaluated by performing compounded Mooney viscosity measurement, 0 ° C. tan δ measurement and 70 ° C. tan δ measurement using the obtained compounded rubber and vulcanized rubber. did. The evaluation results are shown in Table 4 below. The measurement results of the blended Mooney viscosity, 0 ° C. tan δ and 70 ° C. tan δ are shown by indexes with Comparative Example 1 as 100, respectively.

In Table 3, the product names used for each component are as follows.
* 1: BR01 manufactured by JSR, * 2: JOMO Process NC-140 manufactured by Japan Energy, * 3: ZEOSIL 1165MP manufactured by Rhodia, * 4: Dia Black N339 manufactured by Mitsubishi Chemical Corporation, * 5: Si75 manufactured by Evonik, * 6: Ozonon 6C manufactured by Seiko Kagaku Co., Ltd., * 7: Noxeller D manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd., * 8: Noxeller CZ manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.

The compounded Mooney viscosity of each of the modified conjugated diene-based polymers of Examples 1 to 5 was higher than that of the modified conjugated diene-based polymer of Comparative Example 1 in which piperidine was used instead of the compound (A), and the compound (A) was used. It was lower than that of the modified conjugated diene-based polymer of Comparative Example 2 in which piperidine was used instead of, and compound (N—Si-4) was used instead of compound (M).
Further, all of the modified conjugated diene-based polymers of Examples 1 to 5 were excellent in low heat generation and wet grip resistance as compared with the modified conjugated diene-based polymers of Comparative Examples 1 and 2.
From these results, according to the modified conjugated diene polymer obtained by modifying both ends of the conjugated diene polymer with the compound (A) and the compound (M), the modified conjugated diene polymer Mooney It was confirmed that the viscosity can be appropriately increased, whereby the processability of the compounded rubber can be made excellent, and the vulcanized rubber having excellent low heat generation and wet grip resistance can be produced.

（式（１）中、Ｒ^１及びＲ^２は、それぞれ独立に炭素数１〜１８のヒドロカルビル基であり、Ｒ^３は、炭素数１〜２０のヒドロカルビレン基である。Ｒ^４及びＲ^５は、それぞれ独立に水素原子、炭素数１〜１８のヒドロカルビル基、若しくはヒドロカルビル基の炭素−炭素結合間に−ＮＲ^ａ−（ただし、Ｒ^ａはヒドロカルビル基）、−Ｎ＝及び−Ｏ−の少なくともいずれかを有する炭素数２〜１８の１価の基であるか、又は、Ｒ^４及びＲ^５が互いに合わせられこれらが結合する炭素原子と共に構成される環構造を表す。ただし、Ｒ^４及びＲ^５は同時に水素原子にならない。ｎは１〜３の整数である。ｎが１の場合、式中の複数のＲ^１は、互いに同じでも異なっていてもよく、ｎが２又は３の場合、式中の複数のＲ^２は、互いに同じでも異なっていてもよい。） [1] A monomer containing a conjugated diene compound is polymerized in the presence of a metal amide compound obtained by mixing an alkali metal compound or an alkaline earth metal compound with the following compound (A) to obtain a conjugate having an active terminal. A method for producing a modified conjugated diene polymer, which comprises a step of obtaining a diene polymer and a step of reacting the conjugated diene polymer having an active terminal with a compound represented by the following formula (1). ..
(A) A compound having at least one nitrogen-containing group selected from the group consisting of a protected secondary amino group and a tertiary amino group, and one secondary amino group.

(In the formula (1), ^{R 1} and ^{R 2} are each independently a hydrocarbyl group having 1 to 18 carbon atoms, ^{R 3} is .R ⁴ and ^{R 5} is a hydrocarbylene group having 1 to 20 carbon atoms Are each independently a hydrogen atom, a hydrocarbyl group having 1 to 18 carbon atoms, or -NR ^a- (where ^Ra is a hydrocarbyl group), -N = and -O- between carbon-carbon bonds of the hydrocarbyl group. It represents a ring structure that is a monovalent group having any of 2 to 18 carbon atoms, or that R ⁴ and R ⁵ are combined with each other and are composed of carbon atoms to which they are bonded, except that R ⁴ and R are R. ⁵ does not become a hydrogen atom at the same time. N is an integer of 1 to 3. When n is ¹ , a plurality of R 1s in the equation may be the same or different from each other, and when n is 2 or 3, they may be the same or different. a plurality of R ² in the formula may be the same or different from each other.)

（式（４）中、Ｒ^１は炭素数１〜１８のヒドロカルビル基であり、Ｂ^１は、炭素数１〜２０のヒドロカルビルオキシ基、又は、２級アミノ基、保護された２級アミノ基及び３級アミノ基よりなる群から選択される少なくとも一種の窒素含有基を末端に２個以上有する共役ジエン系重合体鎖である。Ｒ^３は、炭素数１〜２０のヒドロカルビレン基である。Ｒ^４及びＲ^５は、それぞれ独立に水素原子、炭素数１〜１８のヒドロカルビル基、若しくはヒドロカルビル基の炭素−炭素結合間に−ＮＲ^ａ−（ただし、Ｒ^ａはヒドロカルビル基）、−Ｎ＝及び−Ｏ−の少なくともいずれかを有する炭素数２〜１８の１価の基であるか、又は、Ｒ^４及びＲ^５が互いに合わせられこれらが結合する炭素原子と共に構成される環構造を表す。ただし、Ｒ^４及びＲ^５は同時に水素原子にならない。Ｐｏｌｙは、２級アミノ基、保護された２級アミノ基及び３級アミノ基よりなる群から選択される少なくとも一種の窒素含有基を末端に２個以上有する共役ジエン系重合体鎖である。ｎは１〜３の整数である。ｎが１の場合、式中の複数のＲ^１は、互いに同じでも異なっていてもよく、ｎが２又は３の場合、式中の複数のＢ^１は、互いに同じでも異なっていてもよい。） [2] A modified conjugated diene-based polymer represented by the following formula (4).

In the formula (4), R ¹ is a hydrocarbyl group having 1 to 18 carbon atoms, and B ¹ is a hydrocarbyloxy group having 1 to 20 carbon atoms, a secondary amino group, a protected secondary amino group and a group. It is a conjugated diene-based polymer chain having at least two or more nitrogen-containing groups selected from the group consisting of tertiary amino groups at the ends. R ³ is a hydrocarbylene group having 1 to 20 carbon atoms. R ⁴ and R ⁵ are independently hydrogen atoms, hydrocarbyl groups having 1 to 18 carbon atoms, or -NR ^a- (where ^Ra is a hydrocarbyl group), -N = and between carbon-carbon bonds of the hydrocarbyl group. or a monovalent group having 2 to 18 carbon atoms and having at least one of -O-, or represents a cyclic structure constituted with the carbon atom to which R ⁴ and R ⁵ are combined they are bound to each other. However , R ⁴ and R ⁵ do not become hydrogen atoms at the same time. Poly ends with at least one nitrogen-containing group selected from the group consisting of a secondary amino group, a protected secondary amino group and a tertiary amino group. It is a conjugated diene polymer chain having one or more groups. N is an integer of ¹ to 3. When n is ¹ , a plurality of R 1s in the formula may be the same or different from each other, and n is 2 or. for 3, a plurality of B ¹ in the formula may be the same or different from each other.)

（式（２）及び式（３）中、Ａ^１、Ａ^２及びＡ^３は、それぞれ独立に、シリル保護基又はヒドロカルビル基である。Ｒ ^６、Ｒ^７、Ｒ^８、Ｒ^９及びＲ^１０は、それぞれ独立にヒドロカルビレン基である。） The compound (A) may be either a chain compound or a cyclic compound, but is preferably a cyclic compound, and more preferably a heterocyclic amine. The compound (A) is particularly preferably at least one selected from the group consisting of the compound represented by the following formula (2) and the compound represented by the following formula (3).

(In formulas (2) and (3), A ¹ , A ² and A ³ are independently silyl protecting groups or hydrocarbyl groups. R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are , Each independently has a hydrocarbylene group.)

Regarding A ¹ , A ² and A ³ of the above formula (2) and formula (3), examples of the hydrocarbyl group include a linear or branched alkyl group, an aryl group and an aralkyl group. The number of carbon atoms of the hydrocarbyl group is preferably 1 to 20, and more preferably 3 to 10.
A ¹ , A ² and A ³ are preferably silyl protecting groups in that the rolling resistance (low heat generation) of the obtained vulcanized rubber can be improved.
The hydrocarbylene groups of R ^{6 to} R ¹⁰ are preferably linear or branched alkanediyl groups. The number of carbon atoms of the hydrocarbylene group is preferably 1 to 10, and more preferably 1 to 3.

（式（１）中、Ｒ^１及びＲ^２は、それぞれ独立に炭素数１〜１８のヒドロカルビル基であり、Ｒ^３は、炭素数１〜２０のヒドロカルビレン基である。Ｒ^４及びＲ^５は、それぞれ独立に水素原子、炭素数１〜１８のヒドロカルビル基、若しくはヒドロカルビル基の炭素−炭素結合間に−ＮＲ^ａ−（ただし、Ｒ^ａはヒドロカルビル基）、−Ｎ＝及び−Ｏ−の少なくともいずれかを有する炭素数２〜１８の１価の基であるか、又は、Ｒ^４及びＲ^５が互いに合わせられこれらが結合する炭素原子と共に構成される環構造を表す。ただし、Ｒ^４及びＲ^５は同時に水素原子にならない。ｎは１〜３の整数である。ｎが１の場合、式中の複数のＲ^１は、互いに同じでも異なっていてもよく、ｎが２又は３の場合、式中の複数のＲ^２は、互いに同じでも異なっていてもよい。） <Degeneration process>
In this step, the active terminal of the conjugated diene polymer obtained in the above polymerization step is reacted with the compound represented by the following formula (1) (hereinafter, also referred to as “(M) compound”). This makes it possible to obtain a modified conjugated diene-based polymer in which a group (secondary amino group) that interacts with silica is introduced at the end of polymerization.

(In the formula (1), ^{R 1} and ^{R 2} are each independently a hydrocarbyl group having 1 to 18 carbon atoms, ^{R 3} is .R ⁴ and ^{R 5} is a hydrocarbylene group having 1 to 20 carbon atoms Are each independently a hydrogen atom, a hydrocarbyl group having 1 to 18 carbon atoms, or -NR ^a- (where ^Ra is a hydrocarbyl group), -N = and -O- between carbon-carbon bonds of the hydrocarbyl group. It represents a ring structure that is a monovalent group having any of 2 to 18 carbon atoms, or that R ⁴ and R ⁵ are combined with each other and are composed of carbon atoms to which they are bonded, except that R ⁴ and R ⁵ are formed. ⁵ does not become a hydrogen atom at the same time. N is an integer of 1 to 3. When n is ¹ , a plurality of R 1s in the equation may be the same or different from each other, and when n is 2 or 3, they may be the same or different. a plurality of R ² in the formula may be the same or different from each other.)

（式（４）中、Ｒ^１は炭素数１〜１８のヒドロカルビル基であり、Ｂ^１は、炭素数１〜２０のヒドロカルビルオキシ基、又は、２級アミノ基、保護された２級アミノ基及び３級アミノ基よりなる群から選択される少なくとも一種の窒素含有基を末端に２個以上有する共役ジエン系重合体鎖である。Ｒ^３は、炭素数１〜２０のヒドロカルビレン基である。Ｒ^４及びＲ^５は、それぞれ独立に水素原子、炭素数１〜１８のヒドロカルビル基、若しくはヒドロカルビル基の炭素−炭素結合間に−ＮＲ^ａ−（ただし、Ｒ^ａはヒドロカルビル基）、−Ｎ＝及び−Ｏ−の少なくともいずれかを有する炭素数２〜１８の１価の基であるか、又は、Ｒ^４及びＲ^５が互いに合わせられこれらが結合する炭素原子と共に構成される環構造を表す。ただし、Ｒ^４及びＲ^５は同時に水素原子にならない。Ｐｏｌｙは、２級アミノ基、保護された２級アミノ基及び３級アミノ基よりなる群から選択される少なくとも一種の窒素含有基を末端に２個以上有する共役ジエン系重合体鎖である。ｎは１〜３の整数である。ｎが１の場合、式中の複数のＲ^１は、互いに同じでも異なっていてもよく、ｎが２又は３の場合、式中の複数のＢ^１は、互いに同じでも異なっていてもよい。） The modified conjugated diene-based polymer obtained by the above polymerization step and modification step is represented by the following formula (4).

In the formula (4), R ¹ is a hydrocarbyl group having 1 to 18 carbon atoms, and B ¹ is a hydrocarbyloxy group having 1 to 20 carbon atoms, a secondary amino group, a protected secondary amino group and a group. It is a conjugated diene-based polymer chain having at least two or more nitrogen-containing groups selected from the group consisting of tertiary amino groups at the ends. R ³ is a hydrocarbylene group having 1 to 20 carbon atoms. R ⁴ and R ⁵ are independently hydrogen atoms, hydrocarbyl groups having 1 to 18 carbon atoms, or -NR ^a- (where ^Ra is a hydrocarbyl group), -N = and between carbon-carbon bonds of the hydrocarbyl group. or a monovalent group having 2 to 18 carbon atoms and having at least one of -O-, or represents a cyclic structure constituted with the carbon atom to which R ⁴ and R ⁵ are combined they are bound to each other. However , R ⁴ and R ⁵ do not become hydrogen atoms at the same time. Poly ends with at least one nitrogen-containing group selected from the group consisting of a secondary amino group, a protected secondary amino group and a tertiary amino group. It is a conjugated diene polymer chain having one or more groups. N is an integer of ¹ to 3. When n is ¹ , a plurality of R 1s in the formula may be the same or different from each other, and n is 2 or. for 3, a plurality of B ¹ in the formula may be the same or different from each other.)

Claims (7)

A conjugated diene-based weight having an active terminal by polymerizing a monomer containing a conjugated diene compound in the presence of a metal amide compound obtained by mixing an alkali metal compound or an alkaline earth metal compound with the compound (A) below. The process of obtaining coalescence and
A step of reacting the conjugated diene polymer having an active terminal with a compound represented by the following formula (1).
A method for producing a modified conjugated diene polymer, which comprises.
(A) A compound having at least one nitrogen-containing group selected from the group consisting of a protected secondary amino group and a tertiary amino group, and one secondary amino group.

(In the formula (1), R ¹ and R ² are independently hydrocarbyl groups having 1 to 18 carbon atoms, R ³ is an alkanediyl group having 1 to 20 carbon atoms, and R ⁴ and R ⁵ are. , Independently hydrogen atom, hydrocarbyl group having 1 to 18 carbon atoms, or -NR ^a- (where ^Ra is a hydrocarbyl group), -N = and -O- between carbon-carbon bonds of the hydrocarbyl group. It represents a ring structure in which it is a monovalent group having 2 to 18 carbon atoms, or R ⁴ and R ⁵ are combined with each other and composed of carbon atoms to which they are bonded, except that R ⁴ and R ^{5 are formed.} is not not .n is an integer of 1 to 3 simultaneously hydrogen atom when .n is 1, a plurality of R ¹ in the formula may be the same or different from each other when n is 2 or 3, wherein a plurality of R ² in may be the same or different from each other.) The modified conjugated diene system according to claim 1, wherein the compound (A) is at least one selected from the group consisting of a compound represented by the following formula (2) and a compound represented by the following formula (3). Method for producing a polymer.

(In formulas (2) and (3), A ¹ , A ² and A ³ are independently silyl protecting groups or hydrocarbyl groups, respectively. R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ is an independent hydrocarbylene group.) The method for producing a conjugated diene polymer according to claim 1 or 2, wherein the monomer further contains an aromatic vinyl compound. A modified conjugated diene polymer represented by the following formula (4).

In the formula (4), R ¹ is a hydrocarbyl group having 1 to 18 carbon atoms, and B ¹ is a hydrocarbyloxy group having 1 to 20 carbon atoms, a secondary amino group, a protected secondary amino group and a group. It is a conjugated diene-based polymer chain having at least two or more nitrogen-containing groups selected from the group consisting of tertiary amino groups at the end. R ³ is an alcandiyl group having 1 to 20 carbon atoms. ⁴ and R ⁵ are independently hydrogen atoms, hydrocarbyl groups having 1 to 18 carbon atoms, or -NR ^a- (where ^Ra is a hydrocarbyl group), -N = and-between carbon-carbon bonds of the hydrocarbyl group. Represents a ring structure that is a monovalent group of 2 to 18 carbon atoms with at least one of O-, or is composed of carbon atoms in which R ⁴ and R ⁵ are combined and bonded together. R ⁴ and R ⁵ do not become hydrogen atoms at the same time. Poly ends with two at least one nitrogen-containing group selected from the group consisting of a secondary amino group, a protected secondary amino group and a tertiary amino group. The conjugated diene polymer chain having the above. N is an integer of 1 to 3. When n is ¹ , a plurality of R 1s in the formula may be the same or different from each other, and n is 2 or 3. for multiple B ¹ in the formula may be the same or different from each other.) A polymer composition containing the modified conjugated diene polymer obtained by the production method according to any one of claims 1 to 3 or the modified conjugated diene polymer according to claim 4, silica, and a cross-linking agent. Stuff. A crosslinked product obtained by cross-linking the polymer composition according to claim 5. A tire in which one or both of a tread and a sidewall is formed by using the polymer composition according to claim 5.