WO2014104169A1 - Method for producing modified conjugated diene rubber - Google Patents

Abstract

Provided is a method for producing a modified conjugated diene rubber which comprises a step of reacting a compound represented by general formula (I) with an active terminal of a polymer obtained by polymerizing a monomer that contains at least a conjugated diene compound using, as a polymerization initiator, an alkali metal aromatic compound which has three or more carbon atoms directly bound to an alkali metal atom and an aromatic ring in one molecule. (I) (In the general formula (I), X is an atom or a reaction group that is capable of reacting with the active terminal of the polymer or a hydrocarbon group that includes either the atom or the reaction group, R¹ to R⁴ are each independently a chemical single bond or an alkylene group having 1 to 10 carbon atoms, and R⁵ to R¹⁰ are each independently an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 12 carbon atoms, wherein R⁵ to R¹⁰ may be bound together in a combination of R⁵ and R⁶, a combination of R⁷ and R⁸, or a combination of R⁹ and R¹⁰ to form a ring structure with a nitrogen atom.)

Description

Process for producing modified conjugated diene rubber

The present invention relates to a method for producing a modified conjugated diene rubber, and more specifically, to produce a modified conjugated diene rubber that is excellent in processability and can provide a crosslinked rubber having low heat buildup and wear resistance. On how to do. The present invention also relates to a modified conjugated diene rubber obtained by this production method, a rubber composition containing the modified conjugated diene rubber, and a crosslinked rubber product thereof.

In recent years, due to environmental problems and resource problems, automobile tires are also strongly required to have low heat build-up, and from the viewpoint of durability, excellent wear resistance is also required. A tire obtained from a rubber composition blended with silica is superior in low heat build-up compared to a tire obtained from a rubber composition blended with commonly used carbon black. can do.

In such a rubber composition, in order to increase the affinity between rubber and silica, a technique for introducing a functional group having a high affinity for silica by reacting a modifier with the polymerization active terminal of the rubber is known. It has been.

For example, Patent Document 1 discloses that a conjugated diene monomer is polymerized using an organolithium catalyst in which a polyvinyl aromatic compound and lithium are prepared at a predetermined molar ratio, and the resulting polymerization active terminal has a modifier. There is disclosed a rubber composition obtained by adding a filler such as silica to a modified conjugated diene rubber obtained by reacting. However, in the technique of Patent Document 1, although the affinity between rubber and silica is improved, there is a problem that low heat generation is not sufficient and wear resistance is inferior. The required characteristics cannot always be satisfied.

In contrast, for example, in Patent Document 2, an alkali metalated aromatic compound having 3 or more carbon atoms directly bonded to an alkali metal atom and an aromatic ring in one molecule is used as a polymerization initiator, and at least a conjugated diene compound. A method for producing a radial conjugated diene polymer is disclosed in which a monomer mixture comprising is polymerized. In this Patent Document 2, by making the conjugated diene polymer have a radial structure, when the filler such as silica is added, the affinity with the filler is improved. The wear resistance can be improved.

JP 2006-306962 A International Publication No. 2010/131646

However, according to the rubber composition obtained by adding a filler to the radial conjugated diene polymer obtained by the production method described in Patent Document 2, low heat build-up and wear resistance can be improved. However, further improvement in low heat buildup and wear resistance is desired from the viewpoint of further performance improvement. In Patent Document 2, the active end of the obtained radial conjugated diene polymer is modified with a modifier to improve low heat buildup and wear resistance. In the technology, depending on the type of modifying agent used and the modification conditions, a part of the radial conjugated diene polymer is gelled, so that there is a problem that workability may be deteriorated.

The present invention has been made in view of such a situation, and produces a modified conjugated diene rubber that is excellent in processability and can provide a rubber cross-linked product having low heat buildup and wear resistance. It aims to provide a method for

As a result of diligent research to achieve the above object, the present inventor has obtained, as a polymerization initiator, an alkali metalated aromatic compound having three or more carbon atoms directly bonded to an alkali metal atom and an aromatic ring in one molecule. Is used to polymerize a monomer containing at least a conjugated diene compound, and a predetermined modifier is reacted with the active terminal of the resulting conjugated diene rubber, thereby providing excellent processability and low heat build-up. The present inventors have found that a modified conjugated diene rubber can be obtained that can provide a rubber cross-linked product having abrasion resistance, and has completed the present invention.

That is, according to the present invention, at least a conjugated diene compound is used as a polymerization initiator by using an alkali metalated aromatic compound having 3 or more carbon atoms directly bonded to an alkali metal atom and an aromatic ring in one molecule. A compound represented by the following general formula (I) at the active end of the conjugated diene rubber having an active terminus by polymerizing a monomer comprising the first step of obtaining a conjugated diene rubber having an active terminus; And a second step of reacting with a modified conjugated diene rubber.

(In the above general formula (I), X represents an atom or a reactive group capable of reacting with the active end of the conjugated diene rubber having the active end, or an active end of the conjugated diene rubber having the active end) A hydrocarbon group containing any one of atoms and reactive groups capable of reacting, and R ¹ to R ⁴ are each independently a chemical single bond or an alkylene group having 1 to 10 carbon atoms. , R ⁵ to R ¹⁰ are each independently an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 12 carbon atoms, and R ⁵ to R ¹⁰ are combinations of R ⁵ and R ⁶ , R And may be combined with each other by a combination of ⁷ and R ⁸ or a combination of R ⁹ and R ¹⁰ to form a ring structure together with the nitrogen atom.)

In the production method of the present invention, in the first step, it is preferable to copolymerize a monomer containing an aromatic vinyl compound in addition to the conjugated diene compound.
In the production method of the present invention, the alkali metalated aromatic compound was obtained by reacting an organic alkali metal compound with an aromatic compound having 3 or more carbon atoms in one molecule directly bonded to an aromatic ring. It is preferable.
In the production method of the present invention, the aromatic compound having 3 or more carbon atoms directly bonded to the aromatic ring in one molecule is preferably an aromatic compound represented by the following general formula (II).

(In the above general formula (II), R ¹¹ to R ¹⁸ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and 3 or more of R ¹¹ to R ¹⁸ have 1 to And p is an integer of 0 to 5, and when p is 2 or more, 3 or more benzene rings are present regardless of the structure represented by the general formula (II). May be condensed with each other at any position.)
In the production method of the present invention, in the compound represented by the general formula (I), X is a halogen atom, R ¹ to R ⁴ are chemical single bonds, and R ⁵ to R ^10. Are preferably each independently an alkyl group having 1 to 5 carbon atoms.
In the production method of the present invention, the amount of the compound represented by the general formula (I) used in the second step is the alkali metal atom 1 in the alkali metalated aromatic compound used in the first step. The amount of atoms or reactive groups capable of reacting with the active terminal of the conjugated diene rubber is preferably in an amount in the range of 0.05 to 5 moles relative to moles.

The present invention also provides a modified conjugated diene rubber obtained by any one of the above production methods.
Furthermore, according to the present invention, there is provided a rubber composition comprising 10 to 200 parts by weight of silica with respect to 100 parts by weight of a rubber component containing the modified conjugated diene rubber.
The rubber composition of the present invention preferably contains a crosslinking agent.

Further, according to the present invention, there are provided a rubber cross-linked product obtained by cross-linking the rubber composition, and a tire comprising the rubber cross-linked product.

According to the present invention, a modified conjugated diene rubber capable of providing a rubber cross-linked product having excellent processability and low heat buildup and wear resistance, and a rubber composition containing the modified conjugated diene rubber And a rubber cross-linked product obtained by using the rubber composition and having low heat build-up and wear resistance.

<Method for producing modified conjugated diene rubber>
The method for producing a modified conjugated diene rubber of the present invention uses, as a polymerization initiator, an alkali metalated aromatic compound having 3 or more carbon atoms directly bonded to an alkali metal atom and an aromatic ring in one molecule, A first step of polymerizing a monomer comprising at least a conjugated diene compound to obtain a conjugated diene rubber having an active end, and a general formula (5) described later at the active end of the conjugated diene rubber having an active end. And a second step of reacting the compound represented by:

<First step>
First, the 1st process in the manufacturing method of this invention is demonstrated. In the production method of the present invention, the first step uses at least an alkali metalated aromatic compound having 3 or more carbon atoms directly bonded to an alkali metal atom and an aromatic ring in one molecule as a polymerization initiator. This is a step of polymerizing a monomer comprising a conjugated diene compound to obtain a conjugated diene rubber having an active end.

The polymerization initiator used in the first step of the production method of the present invention is an alkali metalated aromatic compound having 3 or more carbon atoms directly bonded to each of an alkali metal atom and an aromatic ring in one molecule. The alkali metal atom of the alkali metalated aromatic compound used as a polymerization initiator in the present invention is not particularly limited, but is preferably lithium, sodium, or potassium, and among these, lithium is Particularly preferred. The aromatic ring of the alkali metalated aromatic compound is not particularly limited as long as it is a conjugated ring having aromaticity, and specific examples include electrically neutral such as a benzene ring, a naphthalene ring, and an anthracene ring. An aromatic hydrocarbon ring; an aromatic hydrocarbon ring having a negative charge such as a cyclopentadienyl anion ring, an indenyl anion ring or a fluorenyl anion ring; an aromatic ring containing a heteroatom such as a furan ring or a thiophene ring; And so on. Among these, an electrically neutral aromatic hydrocarbon ring is preferable, and a benzene ring is particularly preferable. An alkali metalated aromatic compound having an electrically neutral aromatic hydrocarbon ring is preferably used from the viewpoint of its stability and polymerization activity.
In the alkali metalated aromatic compound used in the present invention, the alkali metal atom is usually present in a cation state in the alkali metalated aromatic compound, and the alkali metal atom and the aromatic ring The carbon atom directly bonded to each of the carbon atoms is usually present in an anionic state in order to bind to the alkali metal atom in such a cation state. In the alkali metalated aromatic compound used in the present invention, the alkali metal atom thus present in the cation state and the carbon atom present in the anion state form an ionic bond, thereby directly connecting each other. It is in a combined state.

In the present invention, by using an alkali metalated aromatic compound having 3 or more carbon atoms in one molecule directly bonded to each of an alkali metal atom and an aromatic ring as a polymerization initiator, Since the conjugated diene polymer chain grows with living polymerizability from each of the carbon atoms directly bonded to three or more alkali metal atoms contained in the group compound as the polymerization starting point, the resulting conjugated diene The system rubber may have a radial structure.

In addition, the alkali metalated aromatic compound used as a polymerization initiator in the present invention has a structure as long as it has three or more carbon atoms directly bonded to each of an alkali metal atom and an aromatic ring in one molecule. Is not particularly limited. For example, even if three or more carbon atoms directly bonded to an alkali metal atom are directly bonded to one aromatic ring, one carbon atom directly bonded to the alkali metal atom is one. Three or more aromatic rings directly bonded as described above may be bonded via a bonding group.

As an alkali metalated aromatic compound in which three or more carbon atoms directly bonded to an alkali metal atom are directly bonded to one aromatic ring, a compound represented by the following general formula (1) is preferably used. .

In the general formula (1), R ¹⁹ to R ²⁶ each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and an alkali metalation having 1 to 10 carbon atoms in which an alkali metal atom is bonded to the α-position. It represents any atom or group selected from alkyl groups, and three or more of R ¹⁹ to R ²⁶ are alkali metalated alkyl groups having 1 to 10 carbon atoms in which an alkali metal atom is bonded to the α-position. Further, p is an integer of 0 to 5, and when p is 2 or more, regardless of the structure represented by the general formula (1), three or more benzene rings are at arbitrary positions with respect to each other. It may be condensed. For example, when “p” is 2 or more, there are a plurality of R ¹⁹ and R ^22, but a plurality of R ¹⁹ or R ²² may be the same. And it may be different.

In the general formula (1), p is 0, and three of R ²⁰ , R ²¹ , R ²³ , R ²⁴ , R ²⁵ , and R ²⁶ have 1 to 10 of the alkali metalated alkyl groups, and the remainder of R ²⁰ , R ²¹ , R ²³ , R ²⁴ , R ²⁵ , and R ²⁶ is preferably a hydrogen atom.

Alternatively, the alkali metalated aromatic compound in which three or more aromatic rings in which one or more carbon atoms directly bonded to an alkali metal atom are directly bonded via a bonding group is represented by the following general formula (2) Is preferably used.

In the general formula (2), R ²⁷ to R ³¹ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and an alkali metalation having 1 to 10 carbon atoms in which an alkali metal atom is bonded to the α-position. It represents any atom or group selected from alkyl groups, and at least one of R ²⁷ to R ³¹ is an alkali metalated alkyl group having 1 to 10 carbon atoms in which an alkali metal atom is bonded to the α-position. A represents an arbitrary linking group, and q is an integer of 3 to 100. The above “independently” means that, for example, when q is 2 or more, there are a plurality of R ²⁷ to R ^31, but there are a plurality of R ²⁷ , R ²⁸ , R ²⁹ , R ³⁰ , or R ³¹ also means that they may be the same or different.

The method for synthesizing an alkali metalated aromatic compound used as a polymerization initiator in the present invention is not particularly limited, but an organic alkali metal compound is added to an aromatic compound having three or more carbon atoms directly bonded to an aromatic ring in one molecule. Those obtained by reacting are preferably used.

Although it does not specifically limit as an organic alkali metal compound used in order to synthesize | combine the alkali metalated aromatic compound used by this invention, The alkali metal compound which has an alkyl group or an aryl group is used suitably, As the specific example, , Methyl lithium, methyl sodium, methyl potassium, ethyl lithium, ethyl sodium, ethyl potassium, n-propyl lithium, isopropyl potassium, n-butyl lithium, s-butyl lithium, t-butyl lithium, n-butyl sodium, n-butyl Examples include potassium, n-pentyl lithium, n-amyl lithium, n-octyl lithium, phenyl lithium, naphthyl lithium, phenyl sodium, and naphthyl sodium. Among these, an alkali metal compound having an alkyl group is preferable, a lithium compound having an alkyl group is more preferable, and n-butyllithium is particularly preferable.

When alkyl (or aryl) potassium or alkyl (or aryl) sodium is used to synthesize the alkali metalated aromatic compound used in the present invention, a lithium compound having an alkyl group or an aryl group and potassium having an alkoxyl group Alternatively, the target potassium or sodium compound may be obtained by mixing with a sodium compound. Examples of the potassium or sodium compound having an alkoxyl group used at this time include potassium t-butoxy and sodium t-butoxy. The amount of the potassium or sodium compound having an alkoxyl group is not particularly limited, but is usually 0.1 to 5.0 mol, preferably 0.2 to 3.0 mol based on the lithium compound having an alkyl group or an aryl group. Mol, more preferably 0.3 to 2.0 mol.

An aromatic compound having three or more carbon atoms directly bonded to an aromatic ring that can be used for the synthesis of an alkali metalated aromatic compound in one molecule is an alkali metalated aromatic represented by the general formula (1). An aromatic compound for obtaining a compound, an aromatic compound represented by the following general formula (3), and an aromatic compound for obtaining an alkali metalated aromatic compound represented by the above general formula (2) An aromatic compound represented by the following general formula (4) can be exemplified.

In the general formula (3), R ¹¹ to R ¹⁸ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and three or more of R ¹¹ to R ¹⁸ have 1 to 10 carbon atoms. It is an alkyl group. p is an integer of 0 to 5, and when p is 2 or more, three or more benzene rings are condensed at arbitrary positions with each other regardless of the structure represented by the general formula (3). It may be what you did. Note that the above “independently” means that, for example, when p is 2 or more, there are a plurality of R ¹¹ and R ^14, but a plurality of R ¹¹ or R ¹⁴ may be the same. , Meaning it may be different.

In the general formula (3), p is 0, and three of R ¹² , R ¹³ , R ¹⁵ , R ¹⁶ , R ¹⁷ , and R ¹⁸ are alkyl groups having 1 to 10 carbon atoms, R ¹² , It is preferable that the remainder among R ¹³ , R ¹⁵ , R ¹⁶ , R ¹⁷ , and R ¹⁸ is a hydrogen atom.

In the general formula (4), R ³² to R ³⁶ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and one or more of R ³² to R ³⁶ are alkyl having 1 to 10 carbon atoms. It is a group. A represents an arbitrary linking group, and q is an integer of 3 to 100. The above “independently” means that, for example, when q is 2 or more, there are a plurality of R ³² to R ^36, but there are a plurality of R ³² , R ³³ , R ³⁴ , R ³⁵ , or R ³⁶ also means that they may be the same or different.

Specific examples of the aromatic compound represented by the general formula (3) include 1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, hexamethylbenzene, 1,2,3-triethylbenzene, 1,2,4-triethylbenzene, 1,3,5-triethylbenzene, 1,2,3-tripropylbenzene, 1,2,4-tripropylbenzene, 1,3 Benzenes having three or more alkyl groups such as 1,3,5-tributylbenzene, 1,3,5-tripentylbenzene, 2,3,5-trimethylnaphthalene, And naphthalenes having three or more alkyl groups such as 4,5-trimethylnaphthalene.

Specific examples of the aromatic compound represented by the general formula (4) include o-methylstyrene oligomer, m-methylstyrene oligomer, p-methylstyrene oligomer, p-ethylstyrene oligomer, and p-propylstyrene oligomer. And a styrene polymer in which one or more hydrogens on the benzene ring are substituted with an alkyl group, such as p-butylstyrene oligomer and p-pentylstyrene oligomer.

In the present invention, as the alkali metalated aromatic compound used as the polymerization initiator, from the viewpoint that the resulting conjugated diene rubber has a radial structure, 3 carbon atoms directly bonded to the aromatic ring are contained in one molecule. It is preferably obtained by reacting an organic alkali metal compound with an aromatic compound having at least one, and from the viewpoint that the resulting conjugated diene rubber tends to have a more radial structure, the above general formula (3) It is especially preferable that it is a thing obtained by making an organic alkali metal compound react with the aromatic compound represented by these. Therefore, in the present invention, a polymerization initiator in which three or more carbon atoms directly bonded to an alkali metal atom are directly bonded to one aromatic ring, particularly a compound represented by the above general formula (1) is polymerized. It is preferable to use it as an initiator. In addition, these alkali metallized aromatic compounds may be used individually by 1 type, and may be used in combination of 2 or more type.

A method of reacting an organic alkali metal compound with an aromatic compound having 3 or more carbon atoms directly bonded to an aromatic ring in the molecule is not particularly limited, but in an inert solvent under an inert atmosphere. A reaction method is preferably used. The inert solvent used is not particularly limited as long as it can dissolve the compound to be reacted, but a hydrocarbon solvent is preferably used. Specific examples include aliphatic hydrocarbons such as n-hexane, n-heptane, and n-octane; alicyclic hydrocarbons such as cyclohexane, cyclopentane, and methylcyclohexane. In addition, these solvents may be used individually by 1 type, and 2 or more types may be mixed and used for them. Further, the amount of the organic alkali metal compound used for the aromatic compound having 3 or more carbon atoms directly bonded to the aromatic ring in the molecule is not particularly limited, but it is directly on the aromatic ring in the aromatic compound. The amount is usually 0.1 to 100 mol, preferably 0.2 to 50 mol, more preferably 0.3 to 10 mol, particularly preferably 0.3 to 1.1 mol, per 1 mol of bonded carbon atoms. . The reaction time and reaction temperature of this reaction are not particularly limited, but the reaction time is usually in the range of 1 minute to 10 days, preferably 1 minute to 5 days, and the reaction temperature is usually in the range of −50 ° C. to 100 ° C. It is.

In addition, when an organic alkali metal compound is reacted with an aromatic compound having 3 or more carbon atoms bonded directly to an aromatic ring in one molecule, it has a coordination ability to an alkali metal atom for the purpose of accelerating the reaction. A compound may coexist. As the compound having coordination ability to an alkali metal atom, a Lewis base compound containing a hetero atom is preferably used, and among these, a Lewis base compound containing a nitrogen atom or an oxygen atom is particularly preferably used. . Specific examples of Lewis base compounds containing nitrogen or oxygen atoms include chain ether compounds such as diethyl ether, anisole, diphenyl ether, dimethoxybenzene, dimethoxyethane, diglyme and ethylene glycol dibutyl ether; intramolecular such as trimethylamine and triethylamine Tertiary amine compounds having one nitrogen atom in them; Cyclic ether compounds having one oxygen atom in the molecule such as tetrahydrofuran and tetrahydropyran; Nitrogen-containing heterocyclic compounds such as pyridine, lutidine and 1-methylimidazole; Bistetrahydro Cyclic ether compounds having two or more oxygen atoms in the molecule such as furylpropane; N, N, N ′, N′-tetramethylethylenediamine, dipiperidinoethane, 1,4-diazabicyclo [2.2.2 Tertiary amine compounds having two or more nitrogen atoms in the molecule such as octane, (−)-sparteine, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine; hexamethylphosphoamide, etc. And tertiary amide compounds having a nitrogen-heteroatom bond in the molecule.

The amount of the compound having the coordination ability to the alkali metal atom is not particularly limited, and may be determined according to the strength of the coordination ability. For example, as a compound having a coordination ability to an alkali metal atom, a chain ether compound that is a relatively weak coordination ability or a tertiary amine compound having one nitrogen atom in the molecule is used. The amount used is usually in the range of 1 to 100 mol, preferably 5 to 50 mol, more preferably 10 to 25 mol, per mol of the alkali metal atom in the organic alkali metal compound to be reacted with the aromatic compound. . In addition, when using a cyclic ether compound or nitrogen-containing heterocyclic compound having one oxygen atom in the molecule as a compound having a coordination ability to an alkali metal atom, The amount used is usually in the range of 1 to 100 moles, preferably 1 to 20 moles, more preferably 2 to 10 moles per mole of alkali metal atoms in the organic alkali metal compound to be reacted with the aromatic compound. Further, as a compound having a coordination ability to an alkali metal atom, a compound having a relatively strong coordination ability, a cyclic ether compound having two or more oxygen atoms in the molecule, or two or more nitrogen atoms in the molecule In the case of using a tertiary amine compound having a tertiary amine compound having a nitrogen-heteroatom bond in the molecule, the amount used is 1 mol of an alkali metal atom in an organic alkali metal compound to be reacted with an aromatic compound. In general, the range is 0.01 to 5 mol, preferably 0.01 to 2 mol, more preferably 0.01 to 1.5 mol. If the amount of the compound having the coordination ability to the alkali metal atom is too large, the reaction may not proceed. In addition, the compound which has the coordination ability to these alkali metal atoms may be used individually by 1 type, and may be used in combination of 2 or more type.

Radial polymer in conjugated diene rubber obtained by polymerization with particularly good production efficiency of alkali metalated aromatic compounds having 3 or more carbon atoms directly bonded to alkali metal atoms and aromatic rings in one molecule From the viewpoint of increasing the ratio, the compound having a coordination ability to an alkali metal atom is a cyclic ether compound having two or more oxygen atoms in the molecule, or a tertiary amine compound having two or more nitrogen atoms in the molecule. , And at least one compound selected from tertiary amide compounds having a nitrogen-heteroatom bond in the molecule, and the amount of the alkali metal atom 1 in the organic alkali metal compound to be reacted with the aromatic compound A range of 0.02 to 0.4 mol is particularly preferable with respect to mol.

In the case of reacting an organic alkali metal compound with an aromatic compound, when adding a compound capable of coordinating to an alkali metal atom, the order of addition is not particularly limited. However, from the viewpoint of particularly improving the production efficiency of the alkali metalated aromatic compound, after the coexistence of the aromatic compound and the organic alkali metal compound, a compound capable of coordinating to the alkali metal atom is added to the system. The order in which the organic alkali metal compound is added to the system after the coexistence of the aromatic compound and the compound having the ability to coordinate to the alkali metal atom is preferred. By adding in this order, insolubilization due to complex formation between the organic alkali metal compound and the compound capable of coordinating to the alkali metal atom is prevented, and the production efficiency of the alkali metalated aromatic compound is particularly good. Become.

In the first step of the production method of the present invention, for example, the alkali metalated aromatic compound obtained in the above manner and having 3 or more carbon atoms directly bonded to the alkali metal atom and the aromatic ring in one molecule. Is used as a polymerization initiator to polymerize a monomer comprising at least a conjugated diene compound, thereby obtaining a conjugated diene rubber having an active terminal. The conjugated diene compound is not particularly limited. For example, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-3-ethyl-1,3 -Butadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 1,3-cyclohexadiene and the like. Among these, 1,3-butadiene, isoprene or 1,3-pentadiene is preferable, and 1,3-butadiene and isoprene are particularly preferable. In addition, these conjugated diene compounds may be used individually by 1 type, and may be used in combination of 2 or more type.

In the production method of the present invention, the conjugated diene rubber having an active end is preferably obtained by copolymerizing a monomer containing an aromatic vinyl compound in addition to the conjugated diene compound. The aromatic vinyl compound is not particularly limited, and for example, styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, vinylnaphthalene, dimethylaminomethylstyrene, dimethylaminoethylstyrene, and the like. it can. Among these, styrene, α-methylstyrene, or 4-methylstyrene is preferable, and styrene is particularly preferable. Note that. These aromatic vinyl compounds may be used individually by 1 type, and may be used in combination of 2 or more type. The conjugated diene rubber having an active terminal used in the present invention preferably contains 50 to 100% by weight of a conjugated diene monomer unit, particularly preferably contains 55 to 95% by weight, and an aromatic vinyl monomer. Those containing 50 to 0% by weight of monomer units are preferred, and those containing 45 to 5% by weight are particularly preferred.

In addition, in the production method of the present invention, the conjugated diene rubber having an active end is optionally added to the conjugated diene compound and the aromatic vinyl compound in addition to the conjugated diene compound and aromatic vinyl compound as long as the object of the present invention is not impaired. It may be formed by copolymerizing a monomer containing a monomer. Examples of other monomers include α, β-unsaturated nitriles such as acrylonitrile and methacrylonitrile; unsaturated carboxylic acids or acid anhydrides such as acrylic acid, methacrylic acid, and maleic anhydride; methyl methacrylate, acrylic Unsaturated carboxylic acid esters such as ethyl acrylate and butyl acrylate; Non-conjugated dienes such as 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene, dicyclopentadiene, 5-ethylidene-2-norbornene; etc. Can be mentioned. These monomers are preferably 10% by weight or less, more preferably 5% by weight or less as monomer units in the conjugated diene rubber having an active end.

In the production method of the present invention, in the case of obtaining a copolymer using two or more kinds of monomers, the mode of copolymerization is not particularly limited, and any of random, block, and tapered shapes may be used. Although it is good, a random binding mode is preferable. By making it random, the resulting rubber cross-linked product is excellent in low heat build-up.

In the production method of the present invention, since the polymerization reaction usually proceeds with living properties, the use ratio of the alkali metalated aromatic compound and the monomer used as the polymerization initiator to the molecular weight of the target polymer. The amount of alkali metal in the alkali metalated aromatic compound relative to 1 mol of the monomer is usually 0.000001 to 0.1 mol, preferably 0.00001 to 0.05 mol, Particularly preferably, it is selected in the range of 0.0001 to 0.01 mol. If the amount of the alkali metalated aromatic compound used is too small, the molecular weight of the resulting conjugated diene rubber will be too high, making it difficult to handle, and the polymerization reaction may not proceed sufficiently. On the other hand, if the amount of the alkali metalated aromatic compound used is too large, the molecular weight of the resulting conjugated diene rubber will be too low, and the rubber material may be inferior in properties.

In conducting the polymerization reaction, a compound having the ability to coordinate to the alkali metal atom as described above is added to the polymerization reaction system for the purpose of controlling the polymerization rate and the microstructure of the resulting conjugated diene rubber. May be. The amount of the compound having a coordination ability to the alkali metal atom is usually 5 mol or less, preferably 4 mol, per 1 mol of the alkali metal atom in the alkali metalated aromatic compound used as the polymerization initiator. Hereinafter, it is particularly preferably 2 mol or less. If the amount of the compound having coordination ability to these alkali metal atoms is too large, the polymerization reaction may be inhibited. In addition, when preparing the alkali metalated aromatic compound used as a polymerization initiator, when using the compound which has the coordination ability to an alkali metal atom, the solution containing the compound can also be used as it is.

In particular, from the viewpoint that the obtained rubber cross-linked product can be excellent in low heat build-up, a cyclic ether compound having two or more oxygen atoms in the molecule, and a tertiary class having two or more nitrogen atoms in the molecule. An alkali metal compound using at least one compound selected from an amine compound and a tertiary amide compound having a nitrogen-heteroatom bond in the molecule as a polymerization initiator (the alkali metal compound here is an alkali metalation compound) Not limited to aromatic compounds, present in the reaction system and includes all alkali metal compounds that act as polymerization initiators)) in the range of 0.02 to 3.0 moles per mole of alkali metal atoms It is preferable to make it. By doing in this way, the conjugated diene rubber | gum which has moderate vinyl bond content is obtained, As a result, the rubber crosslinked material obtained using this can be made excellent in low heat generation.

In the production method of the present invention, a solution polymerization method is preferably used as the polymerization mode of the monomer containing the conjugated diene compound.

The solvent used in the solution polymerization method is not particularly limited as long as it is inactive in the polymerization reaction and can dissolve the monomer and the polymerization catalyst. Specific examples of the solvent that can be used include aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; aliphatic hydrocarbons such as n-hexane, n-heptane, and n-octane; cyclohexane, cyclopentane, and methylcyclohexane. And the like; and ethers such as tetrahydrofuran, diethyl ether and cyclopentyl methyl ether; Among these, it is preferable to use an aliphatic hydrocarbon or alicyclic hydrocarbon as a solvent because the polymerization activity becomes high. In addition, these solvents may be used individually by 1 type, and 2 or more types may be mixed and used for them.

The concentration of the monomer in the polymerization solution in the solution polymerization method is not particularly limited, but is usually selected in the range of 1 to 50% by weight, preferably 2 to 45% by weight, more preferably 5 to 40% by weight. If the concentration of the monomer in the solution is too low, the productivity of the conjugated diene rubber may be deteriorated. If the concentration is too high, the viscosity of the solution may become too high and handling thereof may be difficult. is there. The polymerization temperature is not particularly limited, but is usually in the range of −30 ° C. to + 200 ° C., preferably 0 ° C. to + 180 ° C. The polymerization time is not particularly limited, and is usually in the range of 1 minute to 100 hours. As the polymerization mode, any of batch mode and continuous mode can be adopted. However, when copolymerizing a conjugated diene compound and an aromatic vinyl compound, a conjugated diene monomer unit and an aromatic vinyl monomer unit are used. The batch method is preferable in that the randomness of the bond can be easily controlled.

As described above, a conjugated diene rubber can be obtained by polymerizing a monomer containing a conjugated diene compound. In the production method of the present invention, the polymerization reaction usually proceeds with a living property, so that a polymer having an active end exists in the polymerization reaction system. Therefore, in the first step, the conjugated diene rubber obtained by the polymerization reaction has an active end. In contrast, in the production method of the present invention, in the second step described later, the compound represented by the general formula (5) described below is reacted with the active end of the conjugated diene rubber obtained by the polymerization reaction. Thus, a modified conjugated diene rubber is obtained. In particular, since the conjugated diene rubber having an active end obtained in the first step in the production method of the present invention has a radial structure, a linear chain in which only one side of the polymer chain is an active end. Compared with the conjugated diene rubber, the number of active ends in one molecule is large and can be efficiently modified, and as a result, the affinity with silica is further improved. Moreover, since it has a radial structure due to the polymerization initiator to be used, a multi-branched structure can be obtained without using a coupling agent.
Hereinafter, the 2nd process in the manufacturing method of the present invention is explained.

<Second step>
In the second step of the production method of the present invention, the modified conjugated diene is produced by reacting the compound represented by the following general formula (5) with the active terminal of the conjugated diene rubber obtained in the first step. This is a process for obtaining a rubber.

In the general formula (5), X reacts with an atom or a reactive group capable of reacting with the active end of the conjugated diene rubber having the active end, or with an active end of the conjugated diene rubber having the active end. Each of R ¹ to R ⁴ is independently a chemical single bond or an alkylene group having 1 to 10 carbon atoms, R ⁵ to R ¹⁰ are each independently an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 12 carbon atoms, R ⁵ to R ¹⁰ are a combination of R ⁵ and R ⁶ , R ⁷ And R ⁸ or a combination of R ⁹ and R ¹⁰ may be bonded to each other to form a ring structure together with the nitrogen atom.

In the production method of the present invention, the conjugated diene rubber is modified by reacting the active terminal of the conjugated diene rubber with the compound represented by the general formula (5), so that it has an affinity for a filler such as silica. The modified conjugated diene rubber obtained can be excellent in processability and can give a rubber cross-linked product having low heat buildup and wear resistance.

In the above general formula (5), the atom or reactive group capable of reacting with the active terminus of the conjugated diene rubber is not particularly limited as long as it can react with the active terminus. From the viewpoint of reactivity, a halogen atom, vinyl group, alkoxyl group, amino group or epoxy group is preferred, an epoxy group or halogen atom is more preferred, a halogen atom is further preferred, and a chlorine atom is particularly preferred.

In the general formula (5), the hydrocarbon group containing any one of the atoms or the reactive groups is not particularly limited, but is preferably a hydrocarbon group having 1 to 10 carbon atoms. This carbon number does not include the number of carbons constituting the reactive group.

In the general formula (5), R ¹ to R ⁴ are each independently a chemical single bond or an alkylene group having 1 to 10 carbon atoms, preferably a chemical single bond or carbon number. It is particularly preferably a 1 to 5 alkylene group and a chemical single bond.

In the general formula (5), R ⁵ to R ¹⁰ are each independently an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 12 carbon atoms, and an alkyl group having 1 to 10 carbon atoms. Group, more preferably an alkyl group having 1 to 5 carbon atoms, and particularly preferably a methyl group.

In particular, in the production method of the present invention, from the viewpoint that the addition effect is particularly high, in the general formula (5), X is a halogen atom, and R ¹ to R ⁴ are all chemical single bonds. A compound in which R ⁵ to R ¹⁰ are each independently an alkyl group having 1 to 5 carbon atoms, X is a chlorine atom, and R ¹ to R ⁴ are all chemical single bonds; Particularly preferred are compounds in which R ⁵ to R ¹⁰ are all methyl groups.

Although the usage-amount of the compound represented by the said General formula (5) is not specifically limited, The active terminal of the conjugated diene rubber | gum per 1 mol of alkali metal atoms in the alkali metalated aromatic compound used as a polymerization initiator is used. The amount of atoms or reactive groups capable of reacting with is preferably 0.05 to 5 mol, more preferably 0.1 to 3 mol, more preferably 0.5 An amount of ˜1.5 mol is particularly preferred. By making the usage-amount of the compound represented by the said General formula (5) into the said range, the addition effect can be made more remarkable. In addition, the compound represented by these said General formula (5) may be used individually by 1 type, and may be used in combination of 2 or more type.

In the second step of the production method of the present invention, the method of reacting the compound represented by the general formula (5) with the active terminal of the conjugated diene rubber obtained in the first step is not particularly limited. However, there is a method of mixing the conjugated diene rubber having an active terminal obtained in the first step and the compound represented by the general formula (5) in a solvent capable of dissolving them. It is done. As the solvent used in this case, those exemplified as the solvent used for the polymerization of the conjugated diene rubber described above can be used. In this case, the conjugated diene rubber having an active end obtained in the first step described above is kept in the polymerization solution used for the polymerization, and is represented by the above general formula (5). The method of adding the compound is simple and preferable. The reaction temperature in the second step is not particularly limited, but is usually 0 to 120 ° C., and the reaction time is not particularly limited, but is usually 1 minute to 1 hour.

When the compound represented by the general formula (5) is reacted with the conjugated diene rubber having an active end, and an unreacted active end remains, alcohol such as methanol, ethanol, isopropanol, water, etc. It is preferable to add a polymerization terminator to the polymerization solution to deactivate the unreacted active terminal.

An anti-aging agent such as a phenol-based stabilizer, a phosphorus-based stabilizer, or a sulfur-based stabilizer may be added to the modified conjugated diene rubber solution obtained as described above, if desired. What is necessary is just to determine suitably the addition amount of an anti-aging agent according to the kind etc. Furthermore, if desired, an extension oil may be blended to form an oil-extended rubber. Examples of extender oils include paraffinic, aromatic and naphthenic petroleum softeners, plant softeners, and fatty acids. When using a petroleum softener, it is preferable that the content of polycyclic aromatics extracted by the method of IP346 (the inspection method of THE INSTITUTE PETROLEUM in the UK) is less than 3%. When the extender oil is used, the amount used is usually 5 to 100 parts by weight with respect to 100 parts by weight of the modified conjugated diene rubber. In addition, the modified conjugated diene rubber after the modification reaction can be obtained by removing the rubber from the solution by, for example, reprecipitation, solvent removal under heating, solvent removal under reduced pressure, or solvent removal by steam (steam stripping). It can be separated and obtained from the reaction mixture by a normal operation during separation.

According to the production method of the present invention, when the conjugated diene compound is polymerized in the first step, 3 or more carbon atoms bonded directly to an alkali metal atom and an aromatic ring as a polymerization initiator in one molecule. The conjugated diene polymer chain is living-polymerizable with each of the carbon atoms directly bonded to three or more alkali metal atoms contained in the alkali metalated aromatic compound as the polymerization starting point. Therefore, the resulting conjugated diene rubber can have a radial structure. In the present invention, in the second step, the compound represented by the general formula (5) is reacted with the active terminal of the conjugated diene rubber having such a radial structure, thereby forming the radial structure. And a modified conjugated diene rubber having a terminal modified with the compound represented by the general formula (5).

The modified conjugated diene rubber of the present invention thus obtained has a radial structure, and thus has an improved affinity with a filler and the like, and further modifies its active terminal. By using the compound represented by the general formula (5) as the modifier, it is possible to effectively prevent the occurrence of gelation (three-dimensional crosslinking) of the conjugated diene rubber during the modification reaction, As a result, workability can be improved. In addition, the modified conjugated diene rubber of the present invention is modified with the compound represented by the above general formula (5) because the active end thereof is modified with the compound represented by the above general formula (5). Can drastically improve the affinity with fillers, etc., which can further improve the low heat buildup and wear resistance when blended with silica and other fillers to make rubber cross-linked products. It is what.

The ratio of the radial conjugated diene rubber (that is, the conjugated diene rubber having three or more branches) in the modified conjugated diene rubber obtained by the production method of the present invention is not particularly limited, but is usually 10 to 100 weights. %, Preferably 20 to 100% by weight. By containing the radial conjugated diene rubber at such a ratio, the processability of the modified conjugated diene rubber can be further improved, and the affinity with a filler such as silica can be further increased. .

The weight average molecular weight of the modified conjugated diene rubber obtained by the production method of the present invention is not particularly limited, but is usually 1,000 to 3,000,000 as a value measured by gel permeation chromatography in terms of polystyrene. The range is preferably 10,000 to 2,000,000, more preferably 100,000 to 1,500,000. By setting the weight average molecular weight of the modified conjugated diene rubber within the above range, it is easy to add silica to the modified conjugated diene rubber, and the rubber composition has excellent processability.

Further, the molecular weight distribution represented by the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the modified conjugated diene rubber obtained by the production method of the present invention is not particularly limited. Is 1.1 to 5.0, particularly preferably 1.2 to 3.0. By setting the molecular weight distribution of the modified conjugated diene rubber within the above range, the resulting rubber cross-linked product is excellent in low heat build-up.

Also, the Mooney viscosity (ML _{1 + 4,} 100 ° C.) of the modified conjugated diene rubber obtained by the production method of the present invention is not particularly limited, but is usually in the range of 20 to 150, preferably 30 to 120. By setting the Mooney viscosity of the modified conjugated diene rubber to the above range, the processability of the rubber composition becomes excellent. When the modified conjugated diene rubber is an oil-extended rubber, the Mooney viscosity of the oil-extended rubber is preferably in the above range.

The vinyl bond content in the conjugated diene unit portion of the modified conjugated diene rubber obtained by the production method of the present invention is usually 1 to 80 mol%, preferably 5 to 75 mol%. By setting the vinyl bond amount within the above range, the obtained rubber cross-linked product has excellent low heat build-up.

<Rubber composition>
The rubber composition of the present invention is a composition comprising 10 to 200 parts by weight of silica with respect to 100 parts by weight of a rubber component containing the modified conjugated diene rubber obtained by the production method of the present invention described above.

Examples of the silica used in the present invention include dry method white carbon, wet method white carbon, colloidal silica, and precipitated silica. Among these, wet method white carbon mainly containing hydrous silicic acid is preferable. Alternatively, a carbon-silica dual phase filler in which silica is supported on the carbon black surface may be used. These silicas can be used alone or in combination of two or more. Is (measured by the BET method according to ASTM D3037-81) nitrogen adsorption specific surface area of silica used is preferably 50 ~ 300m ² / g, more preferably 80 ~ 220m ² / g, particularly preferably 100 ~ 170m ² / g. The pH of silica is preferably 5-10.

The compounding amount of silica in the rubber composition of the present invention is 10 to 200 parts by weight, preferably 30 to 150 parts by weight, more preferably 50 to 100 parts by weight with respect to 100 parts by weight of the rubber component in the rubber composition. Part. By setting the blending amount of silica in the above range, the processability of the rubber composition becomes excellent, and the obtained rubber cross-linked product has excellent wear resistance and low heat build-up.

The rubber composition of the present invention may further contain a silane coupling agent from the viewpoint of further improving the low heat build-up. Examples of the silane coupling agent include vinyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, 3-octathio- 1-propyl-triethoxysilane, bis (3- (triethoxysilyl) propyl) disulfide, bis (3- (triethoxysilyl) propyl) tetrasulfide, γ-trimethoxysilylpropyldimethylthiocarbamyl tetrasulfide, and γ -Trimethoxysilylpropylbenzothiazyl tetrasulfide and the like. These silane coupling agents can be used alone or in combination of two or more. The amount of the silane coupling agent is preferably 0.1 to 30 parts by weight, more preferably 1 to 15 parts by weight with respect to 100 parts by weight of silica.

Further, the rubber composition of the present invention may further contain carbon black such as furnace black, acetylene black, thermal black, channel black, and graphite. Among these, furnace black is preferable. These carbon blacks can be used alone or in combination of two or more. The compounding amount of carbon black is usually 120 parts by weight or less with respect to 100 parts by weight of the rubber component in the rubber composition.

The method of adding silica to the rubber component containing the modified conjugated diene rubber of the present invention is not particularly limited, and a method of adding and kneading a solid rubber component (dry kneading method) or a modified conjugated diene A method (wet kneading method) that is added to a solution containing a rubber and solidified and dried can be applied.

The rubber composition of the present invention preferably further contains a cross-linking agent. Examples of the crosslinking agent include sulfur-containing compounds such as sulfur and sulfur halides, organic peroxides, quinone dioximes, organic polyvalent amine compounds, and alkylphenol resins having a methylol group. Among these, sulfur is preferably used. The amount of the crosslinking agent is preferably 0.1 to 15 parts by weight, more preferably 0.5 to 5 parts by weight, and particularly preferably 1 to 4 parts by weight with respect to 100 parts by weight of the rubber component in the rubber composition. It is.

Further, in addition to the above components, the rubber composition of the present invention includes a crosslinking accelerator, a crosslinking activator, an anti-aging agent, a filler (excluding silica and carbon black), an activator, and a process oil in accordance with conventional methods. , Plasticizers, lubricants, tackifiers and the like can be blended in the required amounts.

When sulfur or a sulfur-containing compound is used as the crosslinking agent, it is preferable to use a crosslinking accelerator and a crosslinking activator in combination. Examples of the crosslinking accelerator include sulfenamide-based crosslinking accelerators; guanidine-based crosslinking accelerators; thiourea-based crosslinking accelerators; thiazole-based crosslinking accelerators; thiuram-based crosslinking accelerators; dithiocarbamic acid-based crosslinking accelerators; A crosslinking accelerator; and the like. Among these, those containing a sulfenamide-based crosslinking accelerator are preferable. These crosslinking accelerators are used alone or in combination of two or more. The amount of the crosslinking accelerator is preferably 0.1 to 15 parts by weight, more preferably 0.5 to 5 parts by weight, and particularly preferably 1 to 4 parts by weight with respect to 100 parts by weight of the rubber component in the rubber composition. Part.

Examples of the crosslinking activator include higher fatty acids such as stearic acid; zinc oxide. These crosslinking activators are used alone or in combination of two or more. The amount of the crosslinking activator is preferably 0.05 to 20 parts by weight, particularly preferably 0.5 to 15 parts by weight based on 100 parts by weight of the rubber component in the rubber composition.

Further, the rubber composition of the present invention may be blended with other rubber other than the modified conjugated diene rubber obtained by the production method of the present invention described above. Examples of other rubbers include natural rubber, polyisoprene rubber, emulsion-polymerized styrene-butadiene copolymer rubber, solution-polymerized styrene-butadiene copolymer rubber, polybutadiene rubber (polybutadiene containing crystal fibers made of 1,2-polybutadiene polymer). Styrene-isoprene copolymer rubber, butadiene-isoprene copolymer rubber, styrene-isoprene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, acrylonitrile-styrene-butadiene copolymer rubber, and the like. . Of these, natural rubber, polyisoprene rubber, polybutadiene rubber, and solution-polymerized styrene-butadiene copolymer rubber are preferable. These rubbers can be used alone or in combination of two or more.

In the rubber composition of the present invention, the modified conjugated diene rubber obtained by the production method of the present invention preferably occupies 10 to 100% by weight, preferably 40 to 100% by weight of the rubber component in the rubber composition. Is particularly preferred. By including the modified conjugated diene rubber obtained by the production method of the present invention in the rubber component at such a ratio, a rubber cross-linked product excellent in low heat buildup and abrasion resistance can be obtained.

In order to obtain the rubber composition of the present invention, each component may be kneaded according to a conventional method. For example, a component excluding a thermally unstable component such as a crosslinking agent or a crosslinking accelerator and a modified conjugated diene rubber are used. After kneading, a heat-unstable component such as a crosslinking agent or a crosslinking accelerator can be mixed with the kneaded product to obtain a desired composition. The kneading temperature of the component excluding the thermally unstable component and the modified conjugated diene rubber is preferably 80 to 200 ° C., more preferably 120 to 180 ° C., and the kneading time is preferably 30 seconds to 30 minutes. It is. The kneaded product and the thermally unstable component are usually mixed after cooling to 100 ° C. or lower, preferably 80 ° C. or lower.

<Rubber cross-linked product>
The rubber cross-linked product of the present invention is obtained by cross-linking the rubber composition of the present invention described above.
The rubber cross-linked product of the present invention uses the rubber composition of the present invention, for example, is molded by a molding machine corresponding to a desired shape, for example, an extruder, an injection molding machine, a compressor, a roll, and heated. Can be produced by carrying out a crosslinking reaction and fixing the shape as a crosslinked product. In this case, crosslinking may be performed after molding in advance, or crosslinking may be performed simultaneously with molding. The molding temperature is usually 10 to 200 ° C, preferably 25 to 120 ° C. The crosslinking temperature is usually 100 to 200 ° C., preferably 130 to 190 ° C., and the crosslinking time is usually 1 minute to 24 hours, preferably 2 minutes to 12 hours, particularly preferably 3 minutes to 6 hours. .

In addition, depending on the shape and size of the rubber cross-linked product, even if the surface is cross-linked, it may not be sufficiently cross-linked to the inside. Therefore, secondary cross-linking may be performed by heating.

As a heating method, a general method used for crosslinking of rubber such as press heating, steam heating, oven heating, hot air heating, etc. may be appropriately selected.

The rubber cross-linked product of the present invention thus obtained is obtained by using the modified conjugated diene rubber obtained by the above-described production method of the present invention, and therefore is excellent in low heat buildup and wear resistance. is there. In particular, the modified conjugated diene rubber obtained by the production method of the present invention is obtained by using the compound represented by the above general formula (5) as a modifier, and therefore, the gelation by the addition of the modifier is not necessary. Therefore, when silica as a filler is added to the modified conjugated diene rubber, the dispersibility of the silica is not lowered due to the influence of the gel content. The rubber cross-linked product of the present invention obtained by using the modified conjugated diene rubber obtained by the production method of the present invention has a good dispersion of silica as a filler, resulting in low heat buildup and wear resistance. It is particularly excellent in properties.

The rubber cross-linked product of the present invention makes use of such characteristics, for example, in tires, materials for each part of the tire such as cap tread, base tread, carcass, sidewall, bead part; hose, belt, mat, anti-proof It can be used in various applications such as vibration rubber and other various industrial article materials; resin impact resistance improvers; resin film buffers; shoe soles; rubber shoes; golf balls; In particular, since the rubber cross-linked product of the present invention is excellent in low heat buildup and wear resistance, it can be suitably used as a tire material, particularly a low fuel consumption tire material.

Hereinafter, the present invention will be described based on more detailed examples, but the present invention is not limited to these examples. In the following, “%” is based on weight unless otherwise specified. Moreover, the test and evaluation followed the following.

[Molecular weight of rubber]
The molecular weight of the rubber was determined as a molecular weight in terms of polystyrene by gel permeation chromatography. Specific measurement conditions were as follows.
Measuring instrument: High-performance liquid chromatograph (trade name “HLC-8220” manufactured by Tosoh Corporation)
Column: A product manufactured by Tosoh Corporation and having two trade names “GMH-HR-H” connected in series was used.
Detector: differential refractometer (trade name “RI-8220” manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Column temperature: 40 ° C

[Branch degree of rubber]
The degree of branching of the rubber was measured with a multi-angle light scattering photometer. Specific measurement conditions were as follows.
Pump: Waters, trade name “MODEL515”
Column: A product manufactured by Tosoh Corporation and having three trade names “GMH-HR-M” connected in series was used.
Detector: Differential refractometer (manufactured by Waters, trade name “RI-2414”)
Detector: Multi-angle light scattering photometer (manufactured by Wyatt Technology, trade name “DAWN EOS”)
Eluent: Tetrahydrofuran Column temperature: 23 ° C

[Rubber microstructure, rubber modification]
^It was measured by ¹ H-NMR.
Measuring instrument: Product name “JNM-ECA-400WB” manufactured by JEOL
Measuring solvent: deuterated chloroform

[Lithiation rate of polymerization initiator]
Measured by GC-MS.
GC: Product name “Agilent GC 6890NGC” manufactured by Agilent Technologies
MS: Product name “Agilent MS 5973MSD” manufactured by Agilent Technologies
Column: Product name “DB1701” manufactured by Agilent Technologies

[Gel weight fraction]
A rubber (weight: Wa [g]) was cut into a # 100 mesh basket by cutting to about 1 mm square, immersed in toluene at room temperature (25 ° C.) for 24 hours, and then pulled up. Next, the rubber remaining in the # 100 mesh basket was vacuum-dried, and the weight after drying (Wb [g]) was weighed. And the gel weight fraction was calculated | required from these weighed values by toluene insoluble content = (Wb / Wa) x100 (%). In addition, it can be judged that it is excellent in workability, so that a gel weight fraction is low.

[Low heat generation]
For a sheet-like test piece having a length of 50 mm, a width of 12.7 mm, and a thickness of 2 mm, a viscoelasticity measuring device (manufactured by Rheometrics, product name “ARES”) is used, and the dynamic strain is 2.5% and the frequency is 10 Hz. Under the conditions, tan δ at 60 ° C. was measured. About this characteristic, it showed with the index | exponent which sets the measured value of the comparative example 1 to 100. The smaller this index, the better the low heat buildup.

(Abrasion resistance)
A disk-shaped test piece having an outer diameter of 50 mm, an inner diameter of 15 mm, and a thickness of 10 mm was measured with a load of 1 kgf and a slip ratio of 15% using an FPS abrasion tester manufactured by Ueshima Seisakusho. About this characteristic, it showed with the index | exponent which sets the measured value of the comparative example 1 to 100. The larger this index, the better the wear resistance.

[Production Example 1: Production of polymerization initiator 1 (lithiation of 1,3,5-trimethylbenzene)]
Under a nitrogen atmosphere, 16 parts of cyclohexane, 0.841 parts of 1,3,5-trimethylbenzene, and 0.813 parts of tetramethylethylenediamine were added to a glass reaction vessel. Next, 1.345 parts of n-butyllithium (0.3 mol of tetramethylethylenediamine per 1 mol of n-butyllithium) was added with stirring, and the reaction was conducted with stirring at a reaction temperature of 60 ° C. for 2 days. 18.999 parts of a solution of polymerization initiator 1 (lithiated 1,3,5-trimethylbenzene) were obtained. Next, for the purpose of measuring the lithiation rate of the lithiated 1,3,5-trimethylbenzene obtained by the reaction, add a few drops of the obtained reaction solution to a glass container to which an excess amount of trimethylsilyl chloride was added. , Reacted for 30 minutes. The catalyst residue was extracted and washed with tap water, and then the solvent was distilled off to obtain a yellow oily liquid.

The yellow oily liquid was subjected to gas chromatograph mass spectrometry (GC-MS). The results were as follows.
EI-MS, m / z = 120 (M +) (3%), m / z = 192 (M +) (3%), m / z = 264 (M +) (24%), m / z = 336 (M + ) (70%). Mw = 120 (3%), Mw = 192 (3%), Mw = 264 (24%), Mw = 336 (70%).

Next, ¹ H-NMR measurement was performed on this yellow oily liquid. The results were as follows.
¹ H-NMR (CDCl ₃ ) 6.83 (s, 3H, Ph—H), 6.73 (s, 1H, Ph—H), 6.64 (s, 2H, Ph—H), 6.55 (S, 2H, Ph-H), 6.47 (s, 1H, Ph-H), 6.39 (s, 3H, Ph-H), 2.30 (s, 9H, Ph-CH ₃ ), 2.28 (s, 6H, Ph—CH ₃ ), 2.02 (s, 2H, Ph—CH ₂ —SiMe ₃ ), 2.26 (s, 3H, Ph—CH ₃ ), 2.00 (s , 4H, Ph—CH ₂ —SiMe ₃ ), 1.98 (s, 6H, Ph—CH ₂ —SiMe ₃ ).

Further, each signal in ¹ H-NMR was assigned by ¹ H-detected multi-bond heteronuclear multiple quantum coherence spectrum-NMR (HMBC-NMR) measurement. The results were as follows.
Unsubstituted product (1,3,5-trimethylbenzene) ¹ H-NMR (CDCl ₃ ): 6.83 (s, 3H, Ph—H), 2.30 (s, 9H, Ph—CH ₃ ), 1 Substituted substance (1-trimethylsilylmethyl-3,5-dimethylbenzene) ¹ H-NMR (CDCl ₃ ): 6.73 (s, 1H, Ph—H), 6.64 (s, 2H, Ph—H), 2.28 (s, 6H, Ph—CH ₃ ), 2.02 (s, 2H, Ph—CH ₂ —SiMe ₃ ), disubstituted (1,3-bis (trimethylsilylmethyl) -5-methylbenzene) ¹ H-NMR (CDCl ₃ ): 6.55 (s, 2H, Ph—H), 6.47 (s, 1H, Ph—H), 2.26 (s, 3H, Ph—CH ₃ ), 2 _{.00 (s, 4H, Ph-} CH 2 -SiMe 3), 3 -substituted bodies (1,3,5-tris Trimethylsilylmethyl) _{^{benzene) 1 H-NMR (CDCl 3}} ): 6.39 (s, 3H, Ph-H), 1.98 (s, 6H, Ph-CH 2 -SiMe 3).

Based on the above assignments by ¹ H-NMR and HMBC-NMR measurements, molecular ion peaks obtained by GC-MS were assigned as follows. EI-MS, m / z = 120 (M +) is unsubstituted (1,3,5-trimethylbenzene), m / z = 192 (M +) is monosubstituted (1-trimethylsilylmethyl-3,5-dimethyl) Benzene), m / z = 264 (M +) is disubstituted (1,3-bis (trimethylsilylmethyl) -5-methylbenzene), m / z = 336 (M +) is trisubstituted (1,3,5) -Tris (trimethylsilylmethyl) benzene). From the above, the ratio (molar ratio) of unsubstituted product: 1 substituted product: 2 substituted product: 3 substituted product was determined to be 3: 3: 24: 70, and the methyl group lithio of 1,3,5-trimethylbenzene was obtained. The conversion rate is 87%, and the average number of lithium atoms introduced into one molecule of 1,3,5-trimethylbenzene is 2.49.

[Example 1]
[Production of Modified Styrene Butadiene Rubber 1]
In a nitrogen atmosphere, an autoclave was charged with 800 parts of cyclohexane, 94.8 parts of 1,3-butadiene, 25.2 parts of styrene, and 0.185 parts of tetramethylethylenediamine, and then the polymerization initiator obtained in Production Example 1 0.812 parts of a solution of 1 (lithiated 1,3,5-trimethylbenzene) (the amount of tetramethylethylenediamine present in the reaction system is sufficient for lithiation of 1,3,5-trimethylbenzene). Polymerization was started at 60 ° C., with 2.0 moles per mole of n-butyllithium used. The polymerization reaction was continued for 60 minutes, and after confirming that the polymerization conversion was in the range of 95% to 100%, tris (dimethylamino) chlorosilane (in the general formula (5), X = Cl, R ¹ to R ⁴ = chemical single bond, R ⁵ to R ¹⁰ = CH ₃ ) 0.157 parts (amount that is 1.0 mol with respect to 1 mol of Li contained in the polymerization initiator 1) ) And reacted for 30 minutes, and then 0.064 part of methanol was added as a polymerization terminator to obtain a solution containing a polymer.

Then, 100 parts of the obtained polymer, 2,4-bis [(octylthio) methyl] -o-cresol (trade name “Irganox 1520”, manufactured by Ciba Specialty Chemicals) 0.15 as an anti-aging agent After adding a part to the solution containing a polymer, the solvent was removed by steam stripping, followed by vacuum drying at 60 ° C. for 24 hours to obtain a solid modified styrene butadiene rubber 1.

The obtained modified styrene butadiene rubber 1 is an elution component (peak area ratio 15.2%) having an Mn of 164,000, an Mw of 207,000, and a molecular weight distribution (Mw / Mn) of 1.27 in GPC measurement. Elution component (peak area ratio 14.6%) with Mn of 381,000, Mw of 386,000, molecular weight distribution (Mw / Mn), and Mn of 741,000, Mw of 784,000, molecular weight Distribution (Mw / Mn) consists of an elution component (peak area ratio 70.2%) of 1.06. As a whole, Mn is 443,000, Mw is 638,000, and molecular weight distribution (Mw / Mn) is 1.44. Moreover, it was confirmed by the multi-angle light scattering measurement that the degree of branching of the peak on the polymer side is high. The modified styrene butadiene rubber 1 had a styrene unit content of 21.8% and a vinyl bond content in the butadiene unit of 60.1 mol%. Further, when ¹ H-NMR of this modified styrene butadiene rubber 1 was measured, it was confirmed that a tris (dimethylamino) silyl group was introduced. The gel weight fraction of this modified styrene butadiene rubber 1 was measured according to the method described above. The results are shown in Table 1.

(Preparation of rubber composition)
Next, 100 parts of the modified styrene butadiene rubber 1 obtained above was masticated for 30 seconds in a Brabender type mixer having a capacity of 250 ml, and then 50 parts of silica (trade name “Zeosil 1115MP”, manufactured by Rhodia), 20 parts of oil (trade name “Aromax T-DAE” manufactured by Nippon Oil Corporation) and silane coupling agent: bis (3- (triethoxysilyl) propyl) tetrasulfide (trade name “Si69” manufactured by Degussa) ) After adding 6.0 parts and kneading at 110 ° C. for 1.5 minutes, 25 parts of silica (trade name “Zeosil 1115MP” manufactured by Rhodia), 3 parts of zinc oxide, 2 parts of stearic acid and anti-aging N-Phenyl-N '-(1,3-dimethylbutyl) -p-phenylenedian (Ouchi Shinsei Chemical Industry Co., Ltd.) , Was added trade name "Nocrac 6C") 2 parts, and further kneaded for 2.5 minutes to discharge the kneaded product from the mixer. The temperature of the kneaded product at the end of kneading was 150 ° C. The kneaded product was cooled to room temperature and then kneaded again in a Brabender type mixer at 110 ° C. for 3 minutes, and then the kneaded product was discharged from the mixer. Next, with an open roll at 50 ° C., the obtained kneaded product, 1.54 parts of sulfur, N-cyclohexyl-2-benzothiazolylsulfenamide (trade name, manufactured by Ouchi Shinsei Chemical Co., Ltd.) as a crosslinking accelerator "Noxeller CZ-G") 1.32 parts and diphenylguanidine (trade name "Noxeller D", manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.), also used as a crosslinking accelerator, are kneaded and then sheet-like rubber The composition was removed. Then, the obtained rubber composition is press-crosslinked at 160 ° C. for 20 minutes to obtain a crosslinked rubber, and the obtained crosslinked rubber (test piece) is evaluated for wear resistance and low heat build-up. I did it. The results are shown in Table 1. In Table 1, the evaluation results of wear resistance and low heat build-up were shown as ratios when the results of Comparative Example 1 described later were set to 100, respectively.

[Example 2]
[Production of modified styrene butadiene rubber 2]
The blending amount of tris (dimethylamino) chlorosilane as a modifier is changed from 0.157 parts to 0.079 parts (amount to be 0.5 moles relative to 1 mole of Li contained in the polymerization initiator 1). A modified styrene butadiene rubber 2 was produced in the same manner as in Example 1 except that. The obtained modified styrene butadiene rubber 2 is an elution component (peak area ratio 15.1%) having an Mn of 161,000, an Mw of 202,000, and a molecular weight distribution (Mw / Mn) of 1.25 in GPC measurement. Elution component (peak area ratio 16.4%) with Mn of 373,000, Mw of 378,000, molecular weight distribution (Mw / Mn), and Mn of 723,000, Mw of 763,000, molecular weight Distribution (Mw / Mn) is composed of 1.06 elution component (peak area ratio 68.5%), Mn is 430,000, Mw is 615,000 as a whole, and molecular weight distribution (Mw / Mn) is It was 1.43. Moreover, it was confirmed by the multi-angle light scattering measurement that the degree of branching of the peak on the polymer side is high. The modified styrene butadiene rubber 2 had a styrene unit content of 21.7% and a vinyl bond content in the butadiene unit of 59.9 mol%. Further, when ¹ H-NMR was measured for the modified styrene butadiene rubber 2, it was confirmed that a tris (dimethylamino) silyl group was introduced. The gel weight fraction of this modified styrene butadiene rubber 2 was measured according to the method described above. The results are shown in Table 1.

Next, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the modified styrene butadiene rubber 2 obtained above was used in place of the modified styrene butadiene rubber 1. Example 1 Evaluation was performed in the same manner as above. The results are shown in Table 1.

[Comparative Example 1]
[Production of modified styrene butadiene rubber 3]
As a modifier, instead of 0.157 part of tris (dimethylamino) chlorosilane, 0.487 part of tetramethoxysilane (amount to be 4.0 moles relative to 1 mole of Li contained in the polymerization initiator 1). A modified styrene butadiene rubber 3 was produced in the same manner as in Example 1 except that it was used. The obtained modified styrene butadiene rubber 3 as a whole had a Mn of 545,000, Mw of 1,004,000, and a molecular weight distribution (Mw / Mn) of 1.84 in GPC measurement. The modified styrene butadiene rubber 3 had a styrene unit content of 21.7% and a vinyl bond content in the butadiene unit of 59.8 mol%. And about this modified styrene butadiene rubber 3, according to the above-mentioned method, the gel weight fraction was measured. The results are shown in Table 1.

Next, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the modified styrene butadiene rubber 3 obtained above was used in place of the modified styrene butadiene rubber 1. Example 1 Evaluation was performed in the same manner as above. The results are shown in Table 1.

[Comparative Example 2]
[Production of Modified Styrene Butadiene Rubber 4]
As a modifier, instead of 0.157 part of tris (dimethylamino) chlorosilane, 0.087 part of trimethylchlorosilane (amount to be 1.0 mole with respect to 1 mole of Li contained in the polymerization initiator 1) is used. A modified styrene butadiene rubber 4 was produced in the same manner as in Example 1 except that it was. The obtained modified styrene butadiene rubber 4 as a whole had Mn of 440,000, Mw of 629,000, and molecular weight distribution (Mw / Mn) of 1.43 in GPC measurement. The modified styrene butadiene rubber 4 had a styrene unit content of 22.3% and a vinyl bond content in the butadiene unit of 60.0 mol%. And about this modified styrene butadiene rubber 4, according to the above-mentioned method, the gel weight fraction was measured. The results are shown in Table 1.

Next, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the modified styrene butadiene rubber 4 obtained above was used instead of the modified styrene butadiene rubber 1. Example 1 Evaluation was performed in the same manner as above. The results are shown in Table 1.

[Comparative Example 3]
[Production of Modified Styrene Butadiene Rubber 5]
As a modifier, instead of 0.157 part of tris (dimethylamino) chlorosilane, 1.756 parts of both-terminal amino-modified polyorganosiloxane (manufactured by Shin-Etsu Silicone Co., Ltd., trade name “KF-8012”) (in polymerization initiator 1) A modified styrene butadiene rubber 5 was produced in the same manner as in Example 1 except that 0.5 mol) was used with respect to 1 mol of Li contained. The obtained modified styrene butadiene rubber 5 as a whole had a Mn of 437,000, Mw of 646,000, and molecular weight distribution (Mw / Mn) of 1.48 in GPC measurement. The modified styrene-butadiene rubber 5 had a styrene unit content of 22.3% and a vinyl bond content in the butadiene unit of 60.0 mol%. And about this modified styrene butadiene rubber 5, according to the above-mentioned method, the gel weight fraction was measured. The results are shown in Table 1.

Next, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the modified styrene butadiene rubber 5 obtained above was used instead of the modified styrene butadiene rubber 1. Example 1 Evaluation was performed in the same manner as above. The results are shown in Table 1.

[Comparative Example 4]
[Production of modified styrene butadiene rubber 6]
As a modifier, instead of 0.157 part of tris (dimethylamino) chlorosilane, 0.086 part of a side chain glycidoxy-modified polyorganosiloxane represented by the following formula (6) (1 mol of Li contained in the polymerization initiator 1) The modified styrene butadiene rubber 6 was produced in the same manner as in Example 1 except that 0.1 mol) was used in the form of a 22% concentration xylene solution. The obtained modified styrene butadiene rubber 6 had an overall Mn of 438,000, Mw of 626,000, and molecular weight distribution (Mw / Mn) of 1.43 in GPC measurement. The modified styrene butadiene rubber 6 had a styrene unit content of 21.5% and a vinyl bond content in the butadiene unit of 59.6 mol%. And about this modified styrene butadiene rubber 6, according to the above-mentioned method, the gel weight fraction was measured. The results are shown in Table 1.

Next, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the modified styrene butadiene rubber 6 obtained above was used in place of the modified styrene butadiene rubber 1. Example 1 Evaluation was performed in the same manner as above. The results are shown in Table 1.

[Comparative Example 5]
[Production of Modified Styrene Butadiene Rubber 7]
In a nitrogen atmosphere, an autoclave was charged with 800 parts of cyclohexane, 94.8 parts of 1,3-butadiene, 25.2 parts of styrene, and 0.232 parts of tetramethylethylenediamine, and 0.051 part of n-butyllithium was added. The polymerization was started at 60 ° C. The polymerization reaction was continued for 60 minutes, and after confirming that the polymerization conversion was in the range of 95% to 100%, 0.157 part of tris (dimethylamino) chlorosilane as a modifier was added and reacted for 30 minutes. Then, 0.064 parts of methanol was added as a polymerization terminator to obtain a solution containing a polymer.

Then, 100 parts of the obtained polymer, 2,4-bis [(octylthio) methyl] -o-cresol (trade name “Irganox 1520”, manufactured by Ciba Specialty Chemicals) 0.15 as an anti-aging agent After adding a part to the solution containing a polymer, the solvent was removed by steam stripping, followed by vacuum drying at 60 ° C. for 24 hours to obtain a solid modified styrene butadiene rubber 7.

The obtained modified styrene butadiene rubber 7 had a Mn of 295,000, a Mw of 312,000, and a molecular weight distribution (Mw / Mn) of 1.06 in GPC measurement. The modified styrene butadiene rubber 7 had a styrene unit content of 21.1% and a vinyl bond content in the butadiene unit of 59.8 mol%. Furthermore, when ¹ H-NMR was measured for the modified styrene butadiene rubber 7, it was confirmed that a tris (dimethylamino) silyl group was introduced. For this modified styrene butadiene rubber 7, the gel weight fraction was measured according to the method described above. The results are shown in Table 1.

Next, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the modified styrene butadiene rubber 7 obtained above was used in place of the modified styrene butadiene rubber 1. Example 1 Evaluation was performed in the same manner as above. The results are shown in Table 1.

From Table 1, an alkali metalated aromatic compound having 3 or more carbon atoms directly bonded to an alkali metal atom and an aromatic ring as a polymerization initiator is used, and the above general formula ( When the compound represented by 5) is used, the gel content of the modified conjugated diene rubber is not substantially contained, and the rubber cross-linked product obtained by using this has low heat build-up and resistance. It was excellent in abrasion (Examples 1 and 2).

On the other hand, when tetramethoxysilane is used as a modifier, the resulting modified conjugated diene rubber contains a large amount of gel, is inferior in workability, and further, when a rubber cross-linked product is used. The results were inferior in low heat build-up and wear resistance (Comparative Example 1).
In addition, when trimethylchlorosilane or both-terminal amino-modified polyorganosiloxane was used as a modifier, the resulting modified conjugated diene rubber had a low gel content, but was a crosslinked rubber product. In this case, the results were inferior in low heat generation and wear resistance (Comparative Examples 2 and 3).
Furthermore, when a side-chain glycidoxy-modified polyorganosiloxane is used as a modifier, the resulting modified conjugated diene rubber contains a large amount of gel, is inferior in processability, and is a crosslinked rubber product. In such a case, the result was inferior to the low exothermic property (Comparative Example 4).
In addition, when n-butyllithium is used as a polymerization initiator, the resulting modified conjugated diene rubber does not substantially contain a gel component. The results were inferior in heat generation and wear resistance, and in particular, inferior in low heat generation (Comparative Example 5).

Claims (11)

1. As a polymerization initiator, an alkali metallized aromatic compound having 3 or more carbon atoms directly bonded to an alkali metal atom and an aromatic ring in one molecule is used to polymerize a monomer comprising at least a conjugated diene compound. And a first step of obtaining a conjugated diene rubber having an active end,
   And a second step of reacting a compound represented by the following general formula (I) with an active terminal of the conjugated diene rubber having the active terminal.
   

   

   (In the above general formula (I), X represents an atom or a reactive group capable of reacting with the active end of the conjugated diene rubber having the active end, or an active end of the conjugated diene rubber having the active end) A hydrocarbon group containing any one of atoms and reactive groups capable of reacting, and R ¹ to R ⁴ are each independently a chemical single bond or an alkylene group having 1 to 10 carbon atoms. , R ⁵ to R ¹⁰ are each independently an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 12 carbon atoms, and R ⁵ to R ¹⁰ are combinations of R ⁵ and R ⁶ , R And may be combined with each other by a combination of ⁷ and R ⁸ or a combination of R ⁹ and R ¹⁰ to form a ring structure together with the nitrogen atom.)
2. The method for producing a modified conjugated diene rubber according to claim 1, wherein, in the first step, a monomer comprising an aromatic vinyl compound in addition to the conjugated diene compound is copolymerized.
3. The alkali metalated aromatic compound is obtained by reacting an organic alkali metal compound with an aromatic compound having 3 or more carbon atoms directly bonded to an aromatic ring in one molecule. A process for producing the modified conjugated diene rubber described in 1.
4. The modified conjugated diene rubber according to claim 3, wherein the aromatic compound having 3 or more carbon atoms directly bonded to the aromatic ring in the molecule is an aromatic compound represented by the following general formula (II). Production method.
   

   

   (In the above general formula (II), R ¹¹ to R ¹⁸ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and 3 or more of R ¹¹ to R ¹⁸ have 1 to And p is an integer of 0 to 5, and when p is 2 or more, 3 or more benzene rings are present regardless of the structure represented by the general formula (II). May be condensed with each other at an arbitrary position.)
5. In the compound represented by the general formula (I), X is a halogen atom, R ¹ to R ⁴ are chemical single bonds, and R ⁵ to R ¹⁰ are each independently a carbon atom. The method for producing a modified conjugated diene rubber according to any one of claims 1 to 4, which is an alkyl group of 1 to 5.
6. In the second step, the amount of the compound represented by the general formula (I) is used with respect to 1 mol of the alkali metal atom in the alkali metalated aromatic compound used in the first step. The method for producing a modified conjugated diene rubber according to any one of claims 1 to 5, wherein the amount of atoms or reactive groups capable of reacting with the active terminal of the rubber is in an amount ranging from 0.05 to 5 mol. .
7. A modified conjugated diene rubber obtained by the production method according to any one of claims 1 to 6.
8. A rubber composition comprising 10 to 200 parts by weight of silica with respect to 100 parts by weight of a rubber component containing the modified conjugated diene rubber according to claim 7.
9. The rubber composition according to claim 8, further comprising a crosslinking agent.
10. A crosslinked rubber product obtained by crosslinking the rubber composition according to claim 9.
11. A tire comprising the rubber cross-linked product according to claim 10.