WO2015046392A1

WO2015046392A1 - Production method for conjugated diene-based rubber

Info

Publication number: WO2015046392A1
Application number: PCT/JP2014/075550
Authority: WO
Inventors: 飯塚　崇; 英順植田
Original assignee: 日本ゼオン株式会社
Priority date: 2013-09-30
Filing date: 2014-09-26
Publication date: 2015-04-02
Also published as: JP6332279B2; JPWO2015046392A1

Abstract

[Problem] To provide a production method for a conjugated diene-based rubber with which crosslinked rubber products exhibiting excellent low heat build-up properties and excellent wet grip properties can be achieved. [Solution] Provided is a production method for a conjugated diene-based rubber, said production method being provided with: a first step in which a polymerization initiator is used to polymerize a compound represented by general formula (1) to obtain a polymer block of the compound represented by general formula (1), said polymer block being provided with active terminals (in general formula (1), R¹ represents hydrogen or a C1-20 hydrocarbon group, and at least one from among X¹ and X² represents an amino-group-protecting group); and a second step in which a monomer including at least a conjugated diene compound is polymerized from the active terminals of the polymer block.

Description

Method for producing conjugated diene rubber

The present invention relates to a method for producing a conjugated diene rubber, and more particularly, to a method for producing a conjugated diene rubber capable of providing a crosslinked rubber having excellent low heat buildup and wet grip properties.

In recent years, due to environmental problems and resource problems, automobile tires are strongly required to have low fuel consumption, and from the viewpoint of safety, excellent wet grip properties are 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.

For example, in Patent Document 1, silica and a silane coupling agent are blended into a conjugated diene polymer obtained by copolymerizing a vinyl compound having a predetermined heteroatom-containing functional group together with a conjugated diene and an aromatic vinyl compound. A tire rubber composition is disclosed. However, in Patent Document 1, although the vinyl compound having a heteroatom-containing functional group is copolymerized to improve the affinity of the conjugated diene polymer for silica, The effect of improving the affinity for silica by introducing a vinyl compound having a heteroatom-containing functional group was limited. Therefore, in the technique of Patent Document 1, the performance expected to be improved by improving the affinity for silica, specifically, low exothermic property and wet grip property, is not always sufficient.

JP 2011-132411 A

The present invention has been made in view of such a situation, and provides a method for producing a conjugated diene rubber capable of providing a rubber cross-linked product excellent in low heat buildup and wet grip properties. Objective.

As a result of earnest research to achieve the above object, the present inventors have an active terminal by polymerizing an aromatic vinyl compound having an amino group protected with a protective group, using a polymerization initiator, A polymer block of an aromatic vinyl compound having an amino group protected by a protecting group is obtained, and a monomer containing at least a conjugated diene compound is polymerized from the active end of the polymer block, thereby reducing heat generation. The present inventors have found that a conjugated diene rubber can be obtained that can give a rubber cross-linked product having excellent properties and wet grip properties.

That is, according to the present invention, using a polymerization initiator, a compound represented by the following general formula (1) is polymerized to obtain a polymer block of the compound represented by the general formula (1) having an active end. There is provided a method for producing a conjugated diene rubber comprising: a first step to be obtained; and a second step in which a monomer comprising at least a conjugated diene compound is polymerized from an active end of the polymer block.

(In the general formula (1), R ¹ is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and at least one of X ¹ and X ² is a protecting group for an amino group.)

Moreover, according to this invention, the conjugated diene type rubber | gum obtained by said manufacturing method is provided.
Alternatively, according to the present invention, using a polymerization initiator, the compound represented by the general formula (1) is polymerized to obtain a polymer block of the compound represented by the general formula (1) having an active terminal. A first step of obtaining, a second step of polymerizing a monomer comprising at least a conjugated diene compound from an active end of the polymer block, and a polymer chain of the conjugated diene rubber obtained in the second step. There is provided a method for producing a modified conjugated diene rubber comprising a third step of reacting an active end with a silane compound having a functional group capable of reacting with the active end.
In the production method of the present invention, the amino-protecting group is preferably a group represented by the following general formula (2).

(In the above general formula (2), R ² to R ⁴ are each independently a group selected from a hydrogen atom and an optionally substituted hydrocarbon group having 1 to 18 carbon atoms. )
In the production method of the present invention, the compound represented by the general formula (1) is p- [N, N-bis (trimethylsilyl) amino] styrene or p- [N, N-bis (trimethylsilyl) amino]. -Α-methylstyrene is preferred.
In the production method of the present invention, it is preferable to use a monomer containing 0 to 50% by weight of an aromatic vinyl compound as the monomer.

Furthermore, according to the present invention, there is provided a modified conjugated diene rubber obtained by the method for producing a modified conjugated diene rubber.

Further, 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 the rubber component containing the conjugated diene rubber or the modified conjugated diene rubber. .
The rubber composition of the present invention preferably contains a crosslinking agent.

Furthermore, according to the present invention, there are provided a crosslinked rubber obtained by crosslinking the rubber composition, and a tire comprising the crosslinked rubber.

According to the present invention, a conjugated diene rubber and a modified conjugated diene rubber, a rubber composition containing the conjugated diene rubber and a modified conjugated diene rubber capable of providing a rubber cross-linked product excellent in low heat buildup and wet grip properties. There can be provided a rubber cross-linked product having a low heat build-up and a wet grip property obtained by cross-linking the rubber composition, and a tire comprising the rubber cross-linked product.

<Method for producing conjugated diene rubber>
The method for producing a conjugated diene rubber according to the present invention comprises using a polymerization initiator to polymerize a compound represented by the general formula (1) described later to obtain a compound represented by the general formula (1) having an active terminal. And a second step of polymerizing a monomer comprising at least a conjugated diene compound from an active end of the polymer block.

<First step>
First, the 1st process in the manufacturing method of this invention is demonstrated. In the first step of the production method of the present invention, the compound represented by the following general formula (1) is polymerized using a polymerization initiator to form a compound represented by the general formula (1) having an active terminal. This is a step of obtaining a polymer block. In addition, the polymer block of the compound represented by the general formula (1) formed in the first step is higher than the filler such as silica in the conjugated diene rubber obtained by the production method of the present invention. It acts as a segment showing affinity, and according to the present invention, the affinity for fillers such as silica can be improved.

In the general formula (1), R ¹ is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom.

In the general formula (1), at least one of X ¹ and X ² is an amino-protecting group. In addition, as such a protective group for an amino group, an amino group that can be deprotected with an acid, a base, or the like, and has at least one hydrogen atom bonded directly to a nitrogen atom by deprotection. There is no particular limitation as long as it is a group to be given. In addition, the groups represented by X ¹ and X ² may be bonded to each other to form a ring. The amino-protecting group contains a silicon atom as an atom directly bonded to the nitrogen atom represented by the general formula (1), and may contain other heteroatoms. It is preferable that it is a group represented by the following general formula (2).

In the general formula (2), R ² to R ⁴ are each independently a group selected from a hydrogen atom and a hydrocarbon group having 1 to 18 carbon atoms which may have a substituent, Is a group selected from an alkyl group having 1 to 18 carbon atoms and an aryl group having 6 to 18 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms which may have a substituent.

Examples of such protecting groups include trimethylsilyl group, triethylsilyl group, tripropylsilyl group, triisopropylsilyl group, tributylsilyl group, ethyldimethylsilyl group, dimethylpropylsilyl group, dimethylisopropylsilyl group, butyldimethylsilyl group. A trialkylsilyl group such as tert-butyldimethylsilyl group, dimethylhexylsilyl group, dimethyloctylsilyl group, decyldimethylsilyl group, dodecyldimethylsilyl group, heptadecyldimethylsilyl group, diethylisopropylsilyl group; Monoalkenyldialkylsilyl groups such as 2- (3-cyclohexen-1-yl) ethyldimethylsilyl group; dimethylphenylsilyl group, benzyldimethylsilyl group, dimethyl-3-phenyl Dialkylmonoarylsilyl groups such as propylsilyl group; monoalkyldiarylsilyl groups such as methyldiphenylsilyl group and tert-butyldiphenylsilyl group; triarylsilyl groups such as triphenylsilyl group; dialkylsilyl such as di-tert-butylsilyl group A group; a diarylsilyl group such as a diphenylsilyl group; Among these, a trimethylsilyl group is preferable from the viewpoint of easy deprotection. In the general formula (1), examples of the groups represented by X ¹ and X ² that are bonded to each other to form a ring include 1,4-disila-1, And divalent silicon-containing hydrocarbylene groups such as 4,4-tetramethyl-butylene group, 1,4-phenylenebis (dimethylsilyl) group, 1-sila-1,1-dimethyl-ethylene group, and the like.

Moreover, in the compound represented by the general formula (1), at least one of X ¹ and X ² may be any amino-protecting group described above, and therefore one of X ¹ and X ² For, a group other than an amino-protecting group may be used. Such a group other than an amino-protecting group is not particularly limited as long as it is a group that is not deprotected by an acid, a base, or the like, but is preferably a group other than a hydrogen atom, and a hetero group other than silicon. An organic group having 1 to 30 carbon atoms which may contain an atom is more preferable, and a hydrocarbon group having 1 to 20 carbon atoms is more preferable. Specific examples of the group other than the amino-protecting group include a methyl group and an ethyl group. As the compound represented by the general formula (1), one of X ¹ and X ² is a compound in which one is a protecting group for an amino group and the other is a group other than a protecting group for an amino group, X ¹ and X ² may both be compounds that are amino-protecting groups, but the resulting conjugated diene rubber can be made more highly compatible with fillers such as silica. From the viewpoint, a compound in which both of X ¹ and X ² are amino-protecting groups is preferred. In this case, X ¹ and X ² may be the same group or different groups.

In the general formula (1), the introduction position of the group represented by —NX ¹ X ² is any of the para position, the meta position, and the ortho position of the group represented by —CR ¹ ═CH _2. The para position is preferable from the viewpoint that the affinity of the resulting conjugated diene rubber with respect to a filler such as silica can be further increased.

Specific examples of the compound represented by the general formula (1) used for constituting the polymer block include p- [N, N-bis (trimethylsilyl) amino] styrene, p- [N, N-bis ( Examples include, but are not limited to, trimethylsilyl) amino] -α-methylstyrene. In addition, the compound represented by these general formula (1) may be used individually by 1 type, and may be used in combination of 2 or more type.

As a polymerization initiator used when polymerizing the compound represented by the above general formula (1), by polymerizing the compound represented by the above general formula (1), the general formula (1) having an active terminal is used. It will not specifically limit if the polymer block of the compound represented can be given. As a specific example thereof, a polymerization initiator mainly containing an organic alkali metal compound, an organic alkaline earth metal compound, a lanthanum series metal compound, or the like is preferably used. Examples of the organic alkali metal compound include organic monolithium compounds such as n-butyllithium, sec-butyllithium, tert-butyllithium, hexyllithium, phenyllithium, and stilbenelithium; dilithiomethane, 1,4-dilithiobutane, 1,4 -Organic polyvalent lithium compounds such as dilithio-2-ethylcyclohexane, 1,3,5-trilithiobenzene, 1,3,5-tris (lithiomethyl) benzene; organic sodium compounds such as sodium naphthalene; organic such as potassium naphthalene Potassium compounds; and the like. Examples of the organic alkaline earth metal compound include di-n-butylmagnesium, di-n-hexylmagnesium, diethoxycalcium, calcium distearate, di-tert-butoxystrontium, diethoxybarium, and diisopropoxybarium. Diethyl mercaptobarium, di-tert-butoxybarium, diphenoxybarium, diethylaminobarium, barium distearate, diketylbarium and the like. As a polymerization initiator having a lanthanum series metal compound as a main catalyst, for example, a lanthanum series metal comprising a lanthanum series metal such as lanthanum, cerium, praseodymium, neodymium, samarium, gadolinium, a carboxylic acid, and a phosphorus-containing organic acid. And a polymerization initiator composed of this salt and a cocatalyst such as an alkylaluminum compound, an organoaluminum hydride compound, and an organoaluminum halide compound. Among these polymerization initiators, an organic monolithium compound and an organic polyvalent lithium compound are preferable, an organic monolithium compound is more preferable, and n-butyllithium is particularly preferable. The organic alkali metal compound is used as an organic alkali metal amide compound by previously reacting with a secondary amine such as dibutylamine, dihexylamine, dibenzylamine, pyrrolidine, hexamethyleneimine, and heptamethyleneimine. Also good. These polymerization initiators may be used individually by 1 type, and may be used in combination of 2 or more type.

In the 1st process of the manufacturing method of this invention, since the polymerization reaction of the compound represented by the said General formula (1) advances with a living property, it represents with a polymerization initiator and the said General formula (1). The use ratio with the compound may be determined according to the molecular weight of the target polymer block, but the use amount of the polymerization initiator with respect to 1 mol of the compound represented by the general formula (1) is preferably 0. It is selected in the range of 0.01 to 0.5 mol, more preferably 0.02 to 0.5 mol, particularly preferably 0.05 to 0.5 mol. If the amount of the polymerization initiator used is too small, the molecular weight of the resulting polymer block of the compound represented by the general formula (1) becomes too high, the viscosity of the conjugated diene rubber becomes high, and the processability is poor. There is a risk. On the other hand, when the amount of the polymerization initiator used is too large, the molecular weight of the resulting polymer block of the compound represented by the general formula (1) becomes too low, and the affinity for the filler of the conjugated diene rubber is low. There is a possibility that the improvement effect is difficult to obtain.

In the production method of the present invention, the polymerization mode of the compound represented by the general formula (1) is preferably a solution polymerization method.

The solvent used in the solution polymerization method is usually used in solution polymerization and is not particularly limited as long as it does not inhibit the polymerization reaction. Specific examples of the inert solvent include chain aliphatic hydrocarbons such as butane, pentane, hexane, heptane, 2-butene; alicyclic hydrocarbons such as cyclopentane, cyclohexane, cyclohexene; benzene, toluene, xylene, etc. Aromatic hydrocarbons; and the like. 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 compound represented by the general formula (1) in the polymerization solution in the solution polymerization method is not particularly limited, but is usually 0.1 to 50% by weight, preferably 0.5 to 45% by weight, more preferably It is selected in the range of 1 to 40% by weight. If the concentration of the compound represented by the general formula (1) 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 becomes too high. It may be difficult to handle. 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 mode such as batch mode or continuous mode can be adopted.

In the polymerization reaction, a polar compound may be added to the polymerization reaction system for the purpose of promoting the polymerization reaction. Examples of the polar compound include ether compounds such as dibutyl ether, tetrahydrofuran and 2,2-di (tetrahydrofuryl) propane; tertiary amines such as tetramethylethylenediamine; alkali metal alkoxides; phosphine compounds; Among these, ether compounds and tertiary amines are preferable, and 2,2-di (tetrahydrofuryl) propane and tetramethylethylenediamine are particularly preferable because they can form a chelate structure with the metal contained in the polymerization initiator. Is particularly preferred. These polar compounds may be used individually by 1 type, and may be used in combination of 2 or more type. The amount of the polar compound used is not particularly limited, but is preferably 0.001 to 100 mol, more preferably 0.01 to 10 mol, relative to 1 mol of the polymerization initiator. By making the usage-amount of the compound which has the coordination ability to an active metal atom into the said range, the addition effect can be made more suitable.

In the first step of the production method of the present invention, the weight average molecular weight (Mw) of the polymer block of the compound represented by the general formula (1) obtained is preferably 400 to 60 as a value in terms of polystyrene. , 000, more preferably 450 to 30,000, still more preferably 500 to 10,000. When the weight average molecular weight (Mw) is too small, the effect of improving the affinity of the conjugated diene rubber with respect to a filler such as silica is obtained by introducing the polymer block of the compound represented by the general formula (1). On the other hand, if the weight average molecular weight (Mw) is too large, the viscosity of the conjugated diene rubber may increase and the processability may deteriorate.

According to the first step in the production method of the present invention as described above, the compound represented by the general formula (1) having an active end is polymerized by polymerizing the compound represented by the general formula (1). Combined blocks can be obtained. In the present invention, the polymer block of the compound represented by the general formula (1) having an active terminal is preferably composed only of the compound represented by the general formula (1). The block in which other compounds are copolymerized is not excluded as long as it is not impaired.

<Second step>
Next, the second step in the production method of the present invention will be described.
In the production method of the present invention, the second step includes at least a conjugated diene compound from the active end of the polymer block of the compound represented by the general formula (1) having the active end obtained in the first step. It is a step of polymerizing the monomer comprising. That is, in the second step of the production method of the present invention, the active end of the polymer block of the compound represented by the general formula (1) having the active end obtained in the first step is used as the polymerization start end. This is a step of polymerizing a monomer containing at least a conjugated diene compound to obtain a polymer chain containing a monomer unit derived from a conjugated diene compound constituting a conjugated diene rubber.

The conjugated diene compound used for the polymerization is not particularly limited. For example, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-3-ethyl- Examples thereof include 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.

Further, the conjugated diene rubber produced by the production method of the present invention is preferably obtained by copolymerizing 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-tert-butylstyrene, 5-tert-butyl-2-methylstyrene, vinylnaphthalene, dimethylaminomethylstyrene, dimethylaminoethylstyrene, the above general formula ( Examples thereof include compounds represented by 1). 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. Conjugated diene compound in a polymer chain containing a conjugated diene compound (that is, a portion excluding the polymer block of the compound represented by the general formula (1)) of the conjugated diene rubber produced by the production method of the present invention The ratio of monomer units derived from (conjugated diene monomer units) and monomer units derived from aromatic vinyl compounds (aromatic vinyl monomer units) is preferably conjugated diene monomer units. It is 50 to 100% by weight, more preferably 55 to 95% by weight, and the aromatic vinyl monomer unit is preferably 0 to 50% by weight, more preferably 5 to 45% by weight.

In addition, in the second step of the production method of the present invention, as long as the object of the present invention is not impaired, if desired, in addition to the conjugated diene compound and the aromatic vinyl compound, other compounds copolymerizable with these are added. It may be copolymerized. Other copolymerizable compounds include, for example, 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 , 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 And the like. These other copolymerizable compounds are polymer chains containing a conjugated diene compound of the conjugated diene rubber produced by the production method of the present invention (that is, a polymer block of a compound represented by the above general formula (1)) In the portion excluding), the monomer unit is preferably 10% by weight or less, and more preferably 5% by weight or less.

In the second step of the production method of the present invention, the mode of copolymerization in the case of obtaining a copolymer using two or more types of monomers is not particularly limited, and any of random shape, block shape, taper shape, etc. However, it is preferably a random binding mode. By making it random, the resulting rubber cross-linked product is excellent in low heat build-up.

In the second step of the production method of the present invention, since the polymerization reaction of the monomer comprising the conjugated diene compound proceeds with living properties, the above-mentioned general having the active terminal obtained in the first step described above. The use ratio of the polymer block of the compound represented by the formula (1) and the monomer comprising the conjugated diene compound may be determined according to the molecular weight of the target conjugated diene rubber, but the conjugated diene The amount of the polymer block of the compound represented by the above general formula (1) having an active terminal with respect to 1 mol of the monomer containing the compound (usually substantially the same as the amount of the polymerization initiator used in the first step) Is preferably selected in the range of 0.05 to 0.8 mmol, more preferably 0.07 to 0.7 mmol, and particularly preferably 0.1 to 0.6 mmol. When the amount of the polymer block of the compound represented by the above general formula (1) having an active terminal with respect to the amount of the monomer used is too small, the molecular weight of the resulting conjugated diene rubber becomes too high to handle. It may be difficult or the polymerization reaction may not proceed sufficiently. On the other hand, if the amount is too large, the molecular weight of the resulting conjugated diene rubber may be too low, and the properties as a rubber material may be deteriorated.

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.

As the solvent used in the solution polymerization method, the same solvent as in the first step described above can be used. From the viewpoint of controlling the polymerization, the solvent containing the conjugated diene compound is dissolved in the solution. It is preferable to add a polymer block of the compound represented by the general formula (1) having an active terminal obtained in the first step.

In conducting the polymerization reaction, the above-mentioned polar compound is added to the polymerization reaction system in order to adjust the polymerization rate and the microstructure of the resulting conjugated diene rubber, specifically the vinyl bond content. Also good. However, at the time of preparing the polymer block of the compound represented by the general formula (1) having an active end, a polar compound in an amount sufficient to adjust the vinyl bond content of the conjugated diene rubber is added to the inert solvent. When added, it is not necessary to newly add a polar compound. The amount of the polar compound used may be determined according to the target vinyl bond content, and is preferably based on 1 mol of the active terminal of the polymer block of the compound represented by the general formula (1) having an active terminal. Is 0.001 to 100 mol, more preferably 0.01 to 10 mol. When the amount of the polar compound used is within this range, it is easy to adjust the vinyl bond content in the conjugated diene monomer unit, and problems due to the deactivation of the active terminal are unlikely to occur.

The concentration of the monomer comprising the conjugated diene compound in the polymerization solution in the polymerization reaction is not particularly limited, but is usually 1 to 50% by weight, preferably 2 to 45% by weight, more preferably 5 to 40% by weight. Selected by range. If the concentration of the monomer comprising the conjugated diene compound 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 becomes too high. Handling may be difficult. 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 random copolymerization of a conjugated diene compound and an aromatic vinyl compound, a conjugated diene monomer unit and an aromatic vinyl monomer are used. The batch method is preferable because the randomness of the bond with the unit is easy to control.

According to the second step of the production method of the present invention, using the polymer block of the compound represented by the general formula (1) having an active terminal obtained in the first step as described above, A conjugated diene rubber can be obtained by polymerizing a monomer comprising a conjugated diene compound.

The weight average molecular weight (Mw) of the conjugated diene rubber obtained in the second step described above is preferably from 100,000 to 1,000,000 as a polystyrene equivalent value measured by gel permeation chromatography, 000 to 700,000 is more preferable, and 150,000 to 500,000 is particularly preferable. When the weight average molecular weight (Mw) of the conjugated diene rubber is within the above range, the resulting rubber cross-linked product has a good balance between strength and low heat build-up.

Further, in the second step of the production method of the present invention, the polymerization reaction of the monomer comprising at least the conjugated diene compound proceeds with a living property, and thus a conjugated diene rubber polymer obtained thereby. The chain will also have an active end. Therefore, in the method for producing a conjugated diene rubber of the present invention, the active terminal of the polymer chain of such a conjugated diene rubber is conventionally used except for silane compounds such as tin tetrachloride, which will be described later. Adding a deactivation step by adding a terminal modifier other than a silane compound described later such as N-methyl-ε-caprolactam or a polymerization terminator such as methanol into the polymerization system. Is preferred.

<Third step>
Alternatively, for the polymer chain of the conjugated diene rubber having an active end obtained in the second step, without providing a step of inactivating the active end of the polymer chain of the conjugated diene rubber, or the conjugated diene Inactivate only part of the active end of the polymer chain of the base rubber, and react with the active end contained in the polymer chain of the conjugated diene rubber with a silane compound having a functional group capable of reacting with the active end A modified conjugated diene rubber may be obtained. That is, in the present invention, a silane compound (hereinafter simply referred to as “silane compound”) having a functional group capable of reacting with the active terminal at the active terminal of the polymer chain of the conjugated diene rubber obtained in the second step described above. In this case, a polymer composed of repeating units represented by the following general formula (3) may be provided. A modified conjugated diene rubber having a block and having a group containing a silicon atom at the other end can be obtained.

(In the general formula (3), R ¹ , X ¹ and X ² are the same as those in the general formula (1).)

The functional group capable of reacting with the active terminal of the polymer chain of the conjugated diene rubber is not particularly limited as long as it can react with the active terminal, but from the viewpoint of reactivity with the active terminal, a halogen atom, A functional group selected from the group consisting of 2-pyrrolidonyl group, vinyl group, alkoxy group, amino group and epoxy group is preferred, and a functional group selected from the group consisting of 2-pyrrolidonyl group, epoxy group and alkoxy group More preferably, an epoxy group is particularly preferable.

Examples of the silane compound used in the present invention include polyorganosiloxane and hydrocarbyloxysilane compounds. The polyorganosiloxane is not particularly limited as long as it has a functional group capable of reacting with the active terminal of the polymer chain of the conjugated diene rubber, and a specific example thereof is represented by the following general formula (4). Examples thereof include polyorganosiloxane. The hydrocarbyloxysilane compound is not particularly limited as long as it has a functional group capable of reacting with the active terminal of the polymer chain of the conjugated diene rubber. Specific examples thereof include the following general formula (5). Hydrocarbyloxysilane compounds represented; tetraalkoxysilane compounds such as tetramethoxysilane and tetraethoxysilane; hexaalkoxysilane compounds such as bis (trimethoxysilyl) ethane and bis (trimethoxysilyl) hexane; methyltriethoxysilane and the like Alkylalkoxysilane compounds; vinylalkoxysilane compounds such as vinyltrimethoxysilane; arylalkoxysilane compounds such as phenyltrimethoxysilane; halogenoalkoxysilane compounds such as triethoxychlorosilane; 3-glycidoxyethyl Epoxy group-containing alkoxysilane compounds such as trimethoxysilane, 3-glycidoxybutylpropyltrimethoxysilane, and bis (3-glycidoxypropyl) dimethoxysilane; sulfur such as bis (3- (triethoxysilyl) propyl) disulfide -Containing alkoxysilane compounds; amino group-containing alkoxysilane compounds such as bis (3-trimethoxysilylpropyl) methylamine; isocyanate group-containing alkoxysilane compounds such as tris (3-trimethoxysilylpropyl) isocyanurate; it can. In addition, examples of the silane compound used in the present invention include tetrahalogenated silane compounds such as tetrachlorosilane. Among these, a polyorganosiloxane represented by the following general formula (4) and a hydrocarbyloxysilane compound represented by the following general formula (5) are preferable. In particular, by using a polyorganosiloxane represented by the following general formula (4), the resulting rubber cross-linked product can be made more excellent in low heat buildup and wet grip properties.

(In the general formula (4), R ⁵ to R ¹² are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms. Y ¹ and Y ⁴ are each independently, the conjugated diene rubber of the polymer chain active terminal functional groups capable of reacting with the alkyl group having 1 to 6 carbon atoms or .Y ² is an aryl group having 6 to 12 carbon atoms, a conjugated diene A functional group capable of reacting with the active end of the polymer chain of the rubber, and a plurality of Y ² may be the same or different from each other, and Y ³ contains 2 to 20 alkylene glycol repeating units. And when there are a plurality of Y ³ , they may be the same or different from each other, p is an integer of 3 to 200, q is an integer of 0 to 200, and r is 0 to 200. (It is an integer.)

In (the general formula ^{(5), R 13} is an alkylene group having 1 to 12 carbon ^{atoms, when R 13} is plural, they mutually identical a good ^{.R 14} be different even ~ R ²² is independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, s is an integer of 1 to 10, and t is an integer of 0 to 2.)

In the polyorganosiloxane represented by the general formula (4), examples of the alkyl group having 1 to 6 carbon atoms constituting R ⁵ to R ¹² , Y ¹ , and Y ⁴ include, for example, methyl group, ethyl group, n -Propyl group, isopropyl group, butyl group, pentyl group, hexyl group, cyclohexyl group and the like. Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group and a methylphenyl group. Among these, a methyl group and an ethyl group are preferable from the viewpoint of ease of production of the polyorganosiloxane itself.

In the polyorganosiloxane represented by the general formula (4), the functional group capable of reacting with the active terminal of the polymer chain of the conjugated diene rubber constituting Y ¹ , Y ² and Y ⁴ has 1 carbon atom. A group having 4 to 12 carbon atoms containing an alkoxy group having 5 to 5 carbon atoms, a hydrocarbon group containing 2-pyrrolidonyl group and an epoxy group is preferred, and a group having 4 to 12 carbon atoms containing an epoxy group is more preferred.

Examples of the alkoxy group having 1 to 5 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, and a butoxy group. Among these, a methoxy group and an ethoxy group are preferable from the viewpoint of reactivity with the active terminal of the polymer chain of the conjugated diene rubber.

Examples of the hydrocarbon group containing a 2-pyrrolidonyl group include those represented by the following general formula (6).

(In the general formula (6), u is an integer of 2 to 10, and is preferably 2.)

Examples of the group having 4 to 12 carbon atoms containing an epoxy group include those represented by the following general formula (7).
-Z ¹ -Z ² -E (7)
(In the above general formula (7), Z ¹ is an alkylene group or alkylarylene group having 1 to 10 carbon atoms, Z ² is a methylene group, a sulfur atom, or an oxygen atom, and E is a carbon having an epoxy group. a substituted hydrocarbon group having 2-10. among these, preferable Z ² is an oxygen atom, Z ² is an oxygen atom, and is more preferable E is a glycidyl group, Z ¹ Is particularly preferably an alkylene group having 3 carbon atoms, Z ² is an oxygen atom, and E is a glycidyl group.

In the polyorganosiloxane represented by the general formula (4), R ⁵ to R ¹² are preferably an alkyl group having 1 to 6 carbon atoms, and Y ¹ and Y ⁴ are Of these, an alkyl group having 1 to 6 carbon atoms is preferable, and Y ² is preferably a group having 4 to 12 carbon atoms containing an epoxy group.

In the polyorganosiloxane represented by the general formula (4), examples of the group containing a repeating unit of Y ³ , that is, an alkylene glycol of 2 to 20, include those represented by the following general formula (8). .

(In the above general formula (8), v is an integer of 2 to 20, P is an alkylene group or alkylarylene group having 2 to 10 carbon atoms, R ²³ is a hydrogen atom or a methyl group, and there are a plurality of them. R ²³ may be the same or different from each other, Q is an alkoxy group having 1 to 10 carbon atoms or an aryloxy group, among which v is an integer of 2 to 8 and P is a carbon number 3 is an alkylene group, R ²³ is a hydrogen atom, and Q is a methoxy group.)

In the polyorganosiloxane represented by the general formula (4), p is an integer of 3 to 200, preferably 3 to 150, more preferably 3 to 120. When the number p is in the above range, the low exothermic property of the obtained rubber cross-linked product can be further improved.

In the polyorganosiloxane represented by the general formula (4), q is an integer of 0 to 200, preferably 0 to 150, more preferably 0 to 120. r is an integer of 0 to 200, preferably 0 to 150, more preferably 0 to 120. The total number of p, q, and r is preferably 3 to 400, more preferably 3 to 300, and particularly preferably 3 to 250. If the total number of p, q, and r is too large, the viscosity of the polymerization solution during the reaction becomes too high, and it may be difficult to produce a modified conjugated diene rubber.

In the polyorganosiloxane represented by the general formula (4), when the epoxy group in the polyorganosiloxane reacts with the active terminal of the polymer chain of the unmodified conjugated diene rubber, at least the polyorganosiloxane in the polyorganosiloxane. It is considered that when a part of the epoxy group is ring-opened, a bond is formed between the carbon atom of the part where the epoxy group is opened and the atom having the active terminal of the polymer chain of the conjugated diene rubber. Further, when the alkoxy group in the polyorganosiloxane reacts with the active terminal of the polymer chain of the conjugated diene rubber, the polyorganosiloxane contains by elimination of at least a part of the alkoxy group in the polyorganosiloxane. It is considered that a bond is formed between the silicon atom and an atom having an active terminal of the polymer chain of the conjugated diene rubber. Further, when the 2-pyrrolidonyl group in the polyorganosiloxane reacts with the active end of the conjugated diene rubber, the carbon-oxygen bond of the carbonyl group constituting at least a part of the 2-pyrrolidonyl group in the polyorganosiloxane is cleaved. Thus, it is considered that a bond is formed between the carbon atom and an atom having an active terminal of the polymer chain of the conjugated diene rubber.

In the hydrocarbyloxysilane compound represented by the general formula (5), the alkyl group having 1 to 6 carbon atoms and the aryl group having 6 to 12 carbon atoms are those described for the polyorganosiloxane of the general formula (4). It is the same.

In the hydrocarbyloxysilane compound represented by the general formula (5), examples of the alkylene group having 1 to 12 carbon atoms include a methylene group, an ethylene group, and a propylene group. Among these, a propylene group is preferable.

Specific examples of the hydrocarbyloxysilane compound represented by the general formula (5) include N, N-bis (trimethylsilyl) -3-aminopropyltrimethoxysilane and N, N-bis (trimethylsilyl) -3-aminopropyl. Examples include triethoxysilane, N, N-bis (trimethylsilyl) aminoethyltrimethoxysilane, and N, N-bis (trimethylsilyl) aminoethyltriethoxysilane.

The amount of the silane compound used is not particularly limited, but the amount of the group having reactivity with respect to the active terminal with respect to 1 mol of the active terminal of the conjugated diene rubber having the active terminal obtained in the second step described above is 0.00. The amount is preferably in the range of 05 to 5 mol, more preferably 0.1 to 3 mol, and particularly preferably 0.3 to 1.5 mol. By making the usage-amount of a silane compound into the said range, the addition effect can be made more remarkable. In addition, a silane compound may be used individually by 1 type, and may be used in combination of 2 or more type.

The method for reacting the silane compound with the active terminal of the polymer chain of the conjugated diene rubber obtained in the second step described above is not particularly limited, but a conjugated diene rubber having an active terminal and a silane compound are used. And a method of mixing them in a solvent capable of dissolving them. As the solvent used in this case, those exemplified as the solvent used in the first step and the second step described above can be used. In this case, the method of adding the silane compound to the conjugated diene rubber having an active end obtained in the second step as described above is kept in the state of the polymerization solution used for the polymerization. Yes, it is preferable. In this case, the silane compound is preferably dissolved in the inert solvent used for the polymerization and added to the polymerization system, and the solution concentration is preferably in the range of 1 to 50% by weight. . The reaction temperature in the modification reaction 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.

The timing of adding the silane compound to the solution containing the conjugated diene rubber having an active terminal obtained in the second step is not particularly limited, but the polymerization reaction is not completed and the conjugated diene having an active terminal is not completed. The state in which the solution containing the rubber system also contains the monomer, more specifically, the solution containing the conjugated diene rubber having an active terminal is 100 ppm or more, more preferably 300 to 50,000 ppm. It is desirable to add a silane compound to this solution in a state containing monomers. By adding the silane compound in this way, side reactions between the conjugated diene rubber having an active terminal and impurities contained in the polymerization system can be suppressed, and the reaction can be controlled well.

In addition, before and after the third step (before and after the silane compound is reacted with the conjugated diene rubber obtained in the second step described above), preferably before the third step, in a range that does not impair the effects of the present invention, A step of coupling a part of the polymer chain of the conjugated diene rubber having an active end by adding a coupling agent such as tin tetrachloride which has been conventionally used in the polymerization system may be added. In addition, before and after the third step (before and after the silane compound is reacted with the conjugated diene rubber obtained in the second step described above), it has been conventionally used as long as the effect of the present invention is not impaired. A step of adding a terminal modifier other than a silane compound such as N-methyl-ε-caprolactam into the polymerization system and modifying a part of the polymer chain of the conjugated diene rubber having an active terminal with a compound other than the silane compound is added. May be. In addition, after the third step (after the silane compound is reacted with the conjugated diene rubber obtained in the second step described above), the polymer chain of the conjugated diene rubber having an active end is in the polymerization system. When remaining, it is preferable to deactivate the active terminal of the conjugated diene rubber having an active terminal by adding a conventionally used polymerization terminator such as methanol into the polymerization system.

Further, in the production method of the present invention, after obtaining the conjugated diene rubber in the second step described above, or when further reacting with the silane compound in the third step, the modified conjugated diene rubber in the third step. In the polymer block of the compound represented by the general formula (1) introduced in the first step described above, an amino group protecting group represented by X ¹ and X ² in the general formula (1) is obtained. A deprotection reaction for deprotection may be performed. As the deprotection reaction, a method using a general acid such as hydrochloric acid or a base such as tetrabutylammonium fluoride can be used without limitation. In particular, by carrying out such a deprotection reaction, an amino group in which at least one hydrogen atom is bonded directly to a nitrogen atom is introduced into the polymer block of the compound represented by the general formula (1). Thereby, the affinity with a filler such as silica can be further increased. The reaction temperature in the deprotection reaction is not particularly limited, but is usually 0 to 120 ° C., and the reaction time is not particularly limited, but is usually 5 minutes to 10 hours. Further, in the present invention, the deprotection reaction for deprotecting the protecting group of the amino group is carried out, for example, by kneading with various compounding agents such as silica to produce a rubber composition. It is good also as an aspect which advances.

If desired, an anti-aging agent such as a phenol stabilizer, a phosphorus stabilizer, or a sulfur stabilizer may be added to the solution of the conjugated diene rubber and modified conjugated diene rubber obtained as described above. . 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 so that the conjugated diene rubber or the modified conjugated diene rubber may be used as the oil extended rubber. Examples of the extender oil 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 conjugated diene rubber or the modified conjugated diene rubber.

The conjugated diene rubber and modified conjugated diene rubber thus obtained are separated from the reaction mixture by removing the solvent by steam stripping or the like, so that a solid conjugated diene rubber is obtained. A modified conjugated diene rubber can be obtained.

The weight average molecular weight (Mw) of the conjugated diene rubber and modified conjugated diene rubber obtained by the production method of the present invention is not particularly limited, but is usually 100, as a value measured by gel permeation chromatography in terms of polystyrene. The range is from 000 to 3,000,000, preferably from 120,000 to 2,000,000, more preferably from 150,000 to 1,500,000. By setting the weight average molecular weight of the conjugated diene rubber and modified conjugated diene rubber within the above range, it becomes easy to add a filler such as silica to the conjugated diene rubber and modified conjugated diene rubber, and the rubber composition is processed. Excellent in properties.

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 conjugated diene rubber and modified conjugated diene rubber obtained by the production method of the present invention is also particularly Although not limited, it is preferably 1.0 to 5.0, particularly preferably 1.0 to 3.0. By setting the molecular weight distribution of the conjugated diene rubber and the modified conjugated diene rubber within the above range, the resulting rubber cross-linked product becomes more excellent in low heat buildup.

The Mooney viscosity (ML _{1 + 4,} 100 ° C.) of the conjugated diene rubber and 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 200, preferably 30 to 150. It is. By setting the Mooney viscosity of the conjugated diene rubber and the modified conjugated diene rubber within the above range, the processability is excellent. When the conjugated diene rubber or the modified conjugated diene rubber is an oil extended rubber, the Mooney viscosity of the oil extended rubber is preferably set in the above range.

The vinyl bond content in the conjugated diene unit portion of the conjugated diene rubber and modified conjugated diene rubber obtained by the production method of the present invention is usually 1 to 80% by weight, preferably 5 to 75% by weight. . 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 conjugated diene rubber or a modified conjugated diene rubber obtained by the production method of the present invention described above (hereinafter, these are collectively referred to as “(modified) conjugated diene rubber”). A composition comprising 10 to 200 parts by weight of silica with respect to 100 parts by weight of a rubber component containing.

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 within the above range, the rubber composition has excellent processability, and the resulting rubber cross-linked product has excellent wet grip properties and low exothermic properties.

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 the solid rubber component (dry kneading method) or ( Modification) A method of adding to a solution containing a conjugated diene rubber and coagulating and drying (wet kneading method) 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, quinonedioximes, 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 rubbers 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 polymerization styrene-butadiene copolymer rubber, solution polymerization styrene-butadiene copolymer rubber, and polybutadiene rubber (high cis-BR and low cis BR). It may also be a polybutadiene rubber containing crystal fibers made of 1,2-polybutadiene polymer), styrene-isoprene copolymer rubber, butadiene-isoprene copolymer rubber, styrene-isoprene-butadiene copolymer rubber, acrylonitrile-butadiene. Of copolymer rubbers, acrylonitrile-styrene-butadiene copolymer rubbers, etc., those other than the above-mentioned (modified) conjugated diene rubbers. 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 accounts for 10 to 100% by weight, and 50 to 100% by weight of the rubber component in the rubber composition. It is particularly preferred to occupy. 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 crosslinked rubber product excellent in low heat buildup and wet grip properties 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 And then kneaded with a thermally unstable component such as a crosslinking agent or a crosslinking accelerator to obtain the desired composition. The kneading temperature of the component excluding the heat labile 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. 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 thus is excellent in low heat buildup and wet grip properties. It is a thing. In particular, the (modified) conjugated diene rubber obtained by the production method of the present invention comprises a polymer block of the compound represented by the general formula (1) on the polymerization initiation terminal side of the polymer chain. It has a high affinity for fillers such as silica. The modified conjugated diene rubber modified with a silane compound has a polymer block of the compound represented by the general formula (1) on the polymerization initiation terminal side of the polymer chain, and at the polymerization termination side terminal. Since it is provided with a modifying group by a modification reaction using a silane compound, the affinity for a filler such as silica is further enhanced. In particular, in the production method of the present invention, the compound represented by the general formula (1) is preferably polymerized alone, and the compound represented by the general formula (1) is introduced in the form of a polymer block. Thus, the affinity for a filler such as silica can be more effectively increased. Therefore, 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 an affinity between the (modified) conjugated diene rubber and silica as a filler. Therefore, it is excellent in low exothermic property and wet grip property.

The rubber cross-linked product of the present invention makes use of such characteristics, and for example, in tires, materials for tire parts such as cap treads, base treads, carcass, sidewalls and bead parts; hoses, belts, mats, 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 wet grip properties, it can be suitably used as a tire material, particularly a low fuel consumption tire material, and is optimal for tread applications.

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, “part” 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 (GPC). 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

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

[Deprotection rate]
The deprotection rate of the conjugated diene rubber and the modified conjugated diene rubber was measured by ¹ H-NMR using a deuterated chloroform solution of the conjugated diene rubber and the modified conjugated diene rubber before and after the deprotection reaction. Specifically, the deprotection rate was determined from the change in intensity ratio between the peak derived from the methyl group bonded to silicon in the vicinity of 0.2 ppm and the peak derived from the vinyl structure at 4.5 to 6.0 ppm.

[Low heat generation]
A test piece having a length of 50 mm, a width of 12.7 mm, and a thickness of 2 mm was measured using a viscoelasticity measuring device (manufactured by Rheometrics, product name “ARES”) under the conditions of a dynamic strain of 2.5% and a frequency of 10 Hz. Tan δ at 0 ° 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 lower this index, the better the low heat buildup.

[Wet grip]
A test piece having a length of 50 mm, a width of 12.7 mm, and a thickness of 2 mm was measured using a viscoelasticity measuring device (manufactured by Rheometrics, product name “ARES”) at a dynamic strain of 0.5% and 10 Hz at 0 ° C. The tan δ was measured. About this characteristic, it showed with the index | exponent which sets the measured value of the comparative example 1 or the comparative example 6 to 100. The higher this index, the better the wet grip.

[Production Example 1: Synthesis of p- [N, N-bis (trimethylsilyl) amino] styrene]
p- [N, N-bis (trimethylsilyl) amino] styrene (a compound represented by the following formula (9)) was prepared according to the method described in “Macromol. Chem. Phys. 2000, 201, 2699-2704”. Synthesized. The structure of the obtained p- [N, N-bis (trimethylsilyl) amino] styrene was confirmed by ¹ H-NMR.

[Production Example 2: Synthesis of p- (dimethylamino) styrene]
p- (Dimethylamino) styrene (compound represented by the following formula (10)) was synthesized according to the method described in “Polymer J. 1988, 20, 791-799”. The structure of the obtained p- (dimethylamino) styrene was confirmed by ¹ H-NMR.

[Example 1]
[Preparation of Conjugated Diene Rubber 1]
To a 100 ml ampoule bottle purged with nitrogen, 23.4 g of cyclohexane and 1.44 mmol of tetramethylethylenediamine were added, and p- [N, N-bis (trimethylsilyl) amino] styrene 0 obtained in Production Example 1 was added. .6 g was added. Next, 1.0 mmol of n-butyllithium was added under stirring and reacted at room temperature for 120 minutes, whereby polymer block 1A of p- [N, N-bis (trimethylsilyl) amino] styrene (p- [N, N-bis (trimethylsilyl) amino] styrene polymer block was obtained at the end of the polymer having hydrocarbyl lithium introduced as the active end. About obtained polymer block 1A, after taking out a very small part, methanol was added to it and the thing which deactivated the active terminal was made into the sample, and the weight average molecular weight (Mw) was measured. The results are shown in Table 1.

Next, 760 g of cyclohexane, 94.8 g of 1,3-butadiene, and 25.2 g of styrene were charged in an autoclave, and then p- [N, N-bis (trimethylsilyl) amino] obtained above was charged. The whole amount of styrene polymer block 1A was added, and 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%, 0.044 mmol of tin tetrachloride was added in the form of a 20% strength cyclohexane solution, and 10 minutes. Reacted. Thereafter, as a polymerization terminator, an amount of methanol corresponding to twice the mole of n-butyllithium used was added to obtain a solution containing the conjugated diene rubber 1.

Subsequently, Irganox 1520L (manufactured by Ciba Specialty Chemicals) as an anti-aging agent was added to 100 parts of the resulting conjugated diene rubber 1 in an autoclave containing a solution containing the conjugated diene rubber 1 obtained. On the other hand, after adding 0.2 part, the solvent was removed by steam stripping, and the solid conjugated diene rubber 1 was obtained by vacuum drying at 60 ° C. for 24 hours.

The obtained conjugated diene rubber 1 was measured for weight average molecular weight (Mw), styrene unit content, vinyl bond content, and p- [N, N-bis (trimethylsilyl) amino] styrene unit content. did. The results are shown in Table 1.

[Preparation of rubber composition and rubber cross-linked product]
In a Brabender type mixer with a capacity of 250 ml, 100 parts of the conjugated diene rubber 1 obtained above is masticated for 30 seconds, and then 50 parts of silica (trade name “Zeosil 1165MP”, manufactured by Rhodia), process oil (new) 5. 25 parts by Nippon Oil Co., Ltd., trade name “Aromax T-DAE”), and silane coupling agent: bis (3- (triethoxysilyl) propyl) tetrasulfide (trade name “Si69”, manufactured by Degussa) After adding 4 parts and kneading for 1.5 minutes starting at 110 ° C., 30 parts of silica (trade name “Zeosil 1165MP” manufactured by Rhodia), 3.0 parts of zinc oxide, 2.0 parts of stearic acid and aging Inhibitor: N-phenyl-N ′-(1,3-dimethylbutyl) -p-phenylenediamine (manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “ It was added crack 6C ") 2.0 parts, and kneaded further 2.5 minutes and drained a kneaded material from the mixer. The temperature of the kneaded product at the end of kneading was 150 ° C. Next, the obtained kneaded product was cooled to room temperature and then kneaded again in a Brabender type mixer at 110 ° C. for 2 minutes, and then the kneaded product was discharged from the mixer. Next, with an open roll at 50 ° C., the obtained kneaded product, 1.7 parts of sulfur and a crosslinking accelerator (N-cyclohexyl-2-benzothiazolylsulfenamide (trade name “Noxeller CZ-G”, Ouchi) After kneading 1.8 parts of Shinsei Chemical Industry Co., Ltd. and 1.1 parts of diphenylguanidine (trade name “Noxeller D”, manufactured by Ouchi Shinsei Chemical Co., Ltd.), a sheet-like rubber composition was taken out. Then, the obtained rubber composition was press-crosslinked at 160 ° C. for 25 minutes to produce a rubber cross-linked product (test piece), and low exothermic properties and wet grip properties were evaluated using this test piece. . The results are shown in Table 1.

[Example 2]
[Preparation of Conjugated Diene Rubber 2]
P- [N, N-bis (trimethylsilyl) amino] styrene obtained in Production Example 1 was prepared in the same manner as in Example 1 except that the amount used was changed from 0.6 g to 1.2 g. [N, N-bis (trimethylsilyl) amino] styrene polymer block 2A (p- [N, N-bis (trimethylsilyl) amino] styrene polymer block is a polymer block in which hydrocarbyl lithium has been introduced as an active end. Combined) was obtained. About obtained polymer block 2A, after taking out a very small part, the thing which added methanol to it and deactivated the active terminal was made into the sample, and the weight average molecular weight (Mw) was measured. The results are shown in Table 1.

The solid conjugated diene rubber 2 was obtained in the same manner as in Example 1 except that the polymer block 2A obtained in this way was used. The average molecular weight (Mw), styrene unit content, vinyl bond content, and p- [N, N-bis (trimethylsilyl) amino] styrene unit content were measured. The results are shown in Table 1.

[Preparation of rubber composition and rubber cross-linked product]
In addition, a rubber composition and a crosslinked rubber product (test piece) were obtained in the same manner as in Example 1 except that the conjugated diene rubber 2 obtained above was used. The wet grip property was evaluated. The results are shown in Table 1.

Example 3
[Preparation of Conjugated Diene Rubber 3]
P- [N, N-bis (trimethylsilyl) amino] styrene obtained in Production Example 1 was prepared in the same manner as in Example 1 except that the amount used was changed from 0.6 g to 6.3 g. [N, N-bis (trimethylsilyl) amino] styrene polymer block 3A (p- [N, N-bis (trimethylsilyl) amino] styrene polymer block is a polymer block in which hydrocarbyl lithium is introduced as an active end. Combined) was obtained. About obtained polymer block 3A, after taking out a very small part, methanol was added to it and the thing which deactivated the active terminal was made into the sample, and the weight average molecular weight (Mw) was measured. The results are shown in Table 1.

Then, a solid conjugated diene rubber 3 was obtained in the same manner as in Example 1 except that the polymer block 3A thus obtained was used. The average molecular weight (Mw), styrene unit content, vinyl bond content, and p- [N, N-bis (trimethylsilyl) amino] styrene unit content were measured. The results are shown in Table 1.

[Preparation of rubber composition and rubber cross-linked product]
In addition, a rubber composition and a crosslinked rubber product (test piece) were obtained in the same manner as in Example 1 except that the conjugated diene rubber 3 obtained above was used. The wet grip property was evaluated. The results are shown in Table 1.

[Comparative Example 1]
[Preparation of Conjugated Diene Rubber 4]
In a nitrogen atmosphere, 760 g of cyclohexane, 94.8 g of 1,3-butadiene, 25.2 g of styrene, and 1.5 g of p- [N, N-bis (trimethylsilyl) amino] styrene obtained in Production Example 1 were placed in an autoclave. Then, 0.8 mmol of n-butyllithium was added, and 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%, 0.044 mmol of tin tetrachloride was added in the form of a 20% strength cyclohexane solution, and 10 minutes. Reacted. Thereafter, as a polymerization terminator, an amount of methanol corresponding to 2 moles of n-butyllithium used was added to obtain a solution containing the conjugated diene rubber 4.

Subsequently, Irganox 1520L (manufactured by Ciba Specialty Chemicals) was added as an anti-aging agent to the autoclave containing the solution containing the conjugated diene rubber 4 thus obtained in an amount of 0 with respect to 100 parts of the conjugated diene rubber 4. After adding 2 parts, the solvent was removed by steam stripping, followed by vacuum drying at 60 ° C. for 24 hours to obtain a solid conjugated diene rubber 4.

The obtained conjugated diene rubber 4 was measured for weight average molecular weight (Mw), styrene unit content, vinyl bond content, and p- [N, N-bis (trimethylsilyl) amino] styrene unit content. did. The results are shown in Table 1.

[Preparation of rubber composition and rubber cross-linked product]
Further, a rubber composition and a crosslinked rubber product (test piece) were obtained in the same manner as in Example 1 except that the conjugated diene rubber 4 obtained above was used. The wet grip property was evaluated. The results are shown in Table 1.

[Comparative Example 2]
[Preparation of Conjugated Diene Rubber 5]
In the same manner as in Comparative Example 1, except that the amount of p- [N, N-bis (trimethylsilyl) amino] styrene obtained in Production Example 1 was changed from 1.5 g to 3.7 g, The conjugated diene rubber 5 was obtained. The obtained conjugated diene rubber 5 was measured for weight average molecular weight (Mw), styrene unit content, vinyl bond content, and p- [N, N-bis (trimethylsilyl) amino] styrene unit content. did. The results are shown in Table 1.

[Preparation of rubber composition and rubber cross-linked product]
Further, a rubber composition and a crosslinked rubber product (test piece) were obtained in the same manner as in Example 1 except that the conjugated diene rubber 5 obtained above was used. The wet grip property was evaluated. The results are shown in Table 1.

[Comparative Example 3]
[Preparation of Conjugated Diene Rubber 6]
Instead of 0.6 g of p- [N, N-bis (trimethylsilyl) amino] styrene obtained in Production Example 1, 1.2 g of p- (dimethylamino) styrene obtained in Production Example 2 was used. Except for the above, in the same manner as in Example 1, polymer block 1B of p- (dimethylamino) styrene (polymer having hydrocarbyl lithium introduced as an active end at the end of p- (dimethylamino) styrene polymer block ) About the obtained polymer block 1B, after taking out a very small part, the thing which added methanol to it and deactivated the active terminal was made into the sample, and the weight average molecular weight (Mw) was measured. The results are shown in Table 1.

Then, a solid conjugated diene rubber 6 was obtained in the same manner as in Example 1 except that the polymer block 1B obtained in this way was used. Average molecular weight (Mw), styrene unit content, vinyl bond content, and p- (dimethylamino) styrene unit content were measured. The results are shown in Table 1.

[Preparation of rubber composition and rubber cross-linked product]
A rubber composition and a crosslinked rubber product (test piece) were obtained in the same manner as in Example 1 except that the conjugated diene rubber 6 obtained above was used. The wet grip property was evaluated. The results are shown in Table 1.

[Comparative Example 4]
[Preparation of Conjugated Diene Rubber 7]
Instead of 1.5 g of p- [N, N-bis (trimethylsilyl) amino] styrene obtained in Production Example 1, 1.5 g of p- (dimethylamino) styrene obtained in Production Example 2 was used. Otherwise, a solid conjugated diene rubber 7 was obtained in the same manner as in Comparative Example 1. Then, the obtained conjugated diene rubber 7 was measured for weight average molecular weight (Mw), styrene unit content, vinyl bond content, and p- (dimethylamino) styrene unit content. The results are shown in Table 1.

[Preparation of rubber composition and rubber cross-linked product]
In addition, a rubber composition and a crosslinked rubber product (test piece) were obtained in the same manner as in Example 1 except that the conjugated diene rubber 7 obtained above was used. The wet grip property was evaluated. The results are shown in Table 1.

[Comparative Example 5]
[Preparation of Conjugated Diene Rubber 8]
A solid conjugated diene rubber 8 was obtained in the same manner as in Comparative Example 1 except that p- [N, N-bis (trimethylsilyl) amino] styrene obtained in Production Example 1 was not used. And about the obtained conjugated diene rubber 8, the weight average molecular weight (Mw), styrene unit content, and vinyl bond content were measured. The results are shown in Table 1.

[Preparation of rubber composition and rubber cross-linked product]
Further, a rubber composition and a crosslinked rubber product (test piece) were obtained in the same manner as in Example 1 except that the conjugated diene rubber 8 obtained above was used. The wet grip property was evaluated. The results are shown in Table 1.

In Table 1, in Examples 1 to 3 and Comparative Examples 1 to 5, the evaluation results of low heat build-up and wet grip properties are shown with the result of Comparative Example 1 being 100. In Table 1, “amino group-containing monomer” means p- [N, N-bis (trimethylsilyl) amino] styrene or p- (dimethylamino) styrene. The “body unit” means a p- [N, N-bis (trimethylsilyl) amino] styrene unit or a p- (dimethylamino) styrene unit.

From Table 1, the rubber cross-linked product obtained using the conjugated diene rubber produced by the production method of the present invention was excellent in low exothermic property and wet grip property (Examples 1 to 3).
On the other hand, the rubber cross-linked product obtained by using the conjugated diene rubber obtained by polymerizing the compound represented by the general formula (1) in a random manner without passing through the first step in the present invention has low exothermic property and It was inferior to both wet grip properties (Comparative Examples 1 and 2).
Further, a conjugated diene rubber produced using an amino group-containing compound different from the compound represented by the general formula (1) or a conjugated diene rubber produced without using an amino group-containing compound The rubber cross-linked product obtained by use was also inferior in both low heat generation properties and wet grip properties (Comparative Examples 3 to 5).

Example 4
[Preparation of Modified Conjugated Diene Rubber 9]
To a 100 ml ampoule bottle purged with nitrogen, 23.4 g of cyclohexane and 1.44 mmol of tetramethylethylenediamine were added, and p- [N, N-bis (trimethylsilyl) amino] styrene 1 obtained in Production Example 1 was added. .2 g was added. Next, 1.0 mmol of n-butyllithium was added with stirring and reacted at room temperature for 120 minutes, whereby polymer block 4A of p- [N, N-bis (trimethylsilyl) amino] styrene (p- [N, N-bis (trimethylsilyl) amino] styrene polymer block was obtained at the end of the polymer having hydrocarbyl lithium introduced as the active end. About obtained polymer block 4A, after taking out a very small part, methanol was added to it and the thing which deactivated the active terminal was made into the sample, and the weight average molecular weight (Mw) was measured. The results are shown in Table 2.

Next, 760 g of cyclohexane, 94.8 g of 1,3-butadiene, and 25.2 g of styrene were charged in an autoclave, and then p- [N, N-bis (trimethylsilyl) amino] obtained above was charged. The whole amount of the styrene polymer block 4A was added, and 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%, 0.044 mmol of tin tetrachloride was added in the form of a 20% strength cyclohexane solution, and 10 minutes. Reacted. Next, the polyorganosiloxane represented by the following formula (11) is converted into a 20% concentration xylene solution so that the epoxy group is in an amount corresponding to 0.5 mol of n-butyllithium used. And allowed to react for 30 minutes. Thereafter, as a polymerization terminator, an amount of methanol corresponding to twice the mole of n-butyllithium used was added to obtain a solution containing the modified conjugated diene rubber 9.

Subsequently, tetrabutylammonium fluoride / tetrahydrofuran solution (manufactured by Stream Chemicals) was added to the autoclave containing the resulting solution containing the modified conjugated diene rubber 9 as tetrabutylammonium fluoride in an amount of 25.0 mmol. By performing a deprotection reaction at 60 ° C. for 100 minutes, a solution containing the deprotected modified conjugated diene rubber 9 was obtained. To this solution, 0.2 part of Irganox 1520L (manufactured by Ciba Specialty Chemicals) as an anti-aging agent is added to 100 parts of the modified conjugated diene rubber 9, and the solvent is removed by steam stripping. The solid modified conjugated diene rubber 9 was obtained by vacuum drying at 60 ° C. for 24 hours.

The modified conjugated diene rubber 9 thus obtained has a weight average molecular weight (Mw), a styrene unit content, a vinyl bond content, and a p- [N, N-bis (trimethylsilyl) amino] styrene unit and its origin. The content of the unit to be measured was measured. The results are shown in Table 2. Further, the deprotection rate of the resulting modified conjugated diene rubber 9 was 96%.

[Preparation of rubber composition and rubber cross-linked product]
In a Brabender type mixer with a capacity of 250 ml, 100 parts of the modified conjugated diene rubber 9 obtained above was masticated for 30 seconds, and then 50 parts of silica (trade name “Zeosil 1165MP”, manufactured by Rhodia), process oil ( 25 parts by Nippon Oil Corporation, trade name “Aromax T-DAE”), and silane coupling agent: bis (3- (triethoxysilyl) propyl) tetrasulfide (trade name “Si69”, manufactured by Degussa) 6 .4 parts was added and kneaded for 1.5 minutes starting at 110 ° C., then 30 parts of silica (trade name “Zeosil 1165MP” manufactured by Rhodia), 3.0 parts of zinc oxide, 2.0 parts of stearic acid and Anti-aging agent: N-phenyl-N '-(1,3-dimethylbutyl) -p-phenylenediamine (manufactured by Ouchi Shinsei Chemical Co., Ltd., product) "NOCRAC 6C") 2.0 parts were added and kneaded further 2.5 minutes and drained a kneaded material from the mixer. The temperature of the kneaded product at the end of kneading was 150 ° C. Next, the obtained kneaded product was cooled to room temperature and then kneaded again in a Brabender type mixer at 110 ° C. for 2 minutes, and then the kneaded product was discharged from the mixer. Next, with an open roll at 50 ° C., the obtained kneaded product, 1.7 parts of sulfur and a crosslinking accelerator (N-cyclohexyl-2-benzothiazolylsulfenamide (trade name “Noxeller CZ-G”, Ouchi) After kneading 1.8 parts of Shinsei Chemical Industry Co., Ltd. and 1.1 parts of diphenylguanidine (trade name “Noxeller D”, manufactured by Ouchi Shinsei Chemical Co., Ltd.), a sheet-like rubber composition was taken out. Then, the obtained rubber composition was press-crosslinked at 160 ° C. for 25 minutes to produce a rubber cross-linked product (test piece), and low exothermic properties and wet grip properties were evaluated using this test piece. . The results are shown in Table 2.

Example 5
[Preparation of Modified Conjugated Diene Rubber 10]
P- [N, N-bis (trimethylsilyl) amino] styrene obtained in Production Example 1 was prepared in the same manner as in Example 4 except that the amount used was changed from 1.2 g to 2.6 g. [N, N-bis (trimethylsilyl) amino] styrene polymer block 5A (p- [N, N-bis (trimethylsilyl) amino] styrene polymer block is a polymer block in which hydrocarbyl lithium has been introduced as an active end. Combined) was obtained. About obtained polymer block 5A, after taking out a very small part, methanol was added to it and the thing which deactivated the active terminal was made into the sample, and the weight average molecular weight (Mw) was measured. The results are shown in Table 2.

And while using the polymer block 5A obtained in this way, the addition amount as the amount of tetrabutylammonium fluoride in the tetrabutylammonium fluoride / tetrahydrofuran solution was changed from 25.0 mmol to 50.0 mmol. In the same manner as in Example 4, a modified conjugated diene rubber 10 was obtained, and the resulting modified conjugated diene rubber 10 was obtained with respect to weight average molecular weight (Mw), styrene unit content, vinyl bond content, and p. The content of-[N, N-bis (trimethylsilyl) amino] styrene units and units derived therefrom was measured. The results are shown in Table 2. Moreover, the deprotection rate of the obtained modified conjugated diene rubber 10 was 93%.

[Preparation of rubber composition and rubber cross-linked product]
Further, a rubber composition and a crosslinked rubber product (test piece) were obtained in the same manner as in Example 4 except that the modified conjugated diene rubber 10 obtained above was used. Similarly, low exothermic property was obtained. And the wet grip property was evaluated. The results are shown in Table 2.

Example 6
[Preparation of Modified Conjugated Diene Rubber 11]
An autoclave was charged with 760 g of cyclohexane, 94.8 g of 1,3-butadiene, and 25.2 g of styrene in a nitrogen atmosphere, and then p- [N, N-bis (trimethylsilyl) obtained in the same manner as in Example 5. Amino] styrene polymer block 5A was added in the same amount as in Example 5, and 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%, 0.044 mmol of tin tetrachloride was added in the form of a 20% strength cyclohexane solution, and 10 minutes. Reacted. Next, the polyorganosiloxane represented by the above formula (11) is brought into a 20% concentration xylene solution state so that the epoxy group is in an amount corresponding to 0.5 mol of n-butyllithium used. And allowed to react for 30 minutes. Thereafter, as a polymerization terminator, a solution containing the modified conjugated diene rubber 11 was obtained by adding an amount of methanol corresponding to twice the mole of n-butyllithium used.

Next, Irganox 1520L (manufactured by Ciba Specialty Chemicals) was added as an anti-aging agent to the resulting solution containing the modified conjugated diene rubber 11 in an amount of 0.000 with respect to 100 parts of the resulting modified conjugated diene rubber 11. After the addition of 2 parts, the solvent was removed by steam stripping and vacuum-dried at 60 ° C. for 24 hours to obtain a solid modified conjugated diene rubber 11.

The resulting modified conjugated diene rubber 11 has a weight average molecular weight (Mw), a styrene unit content, a vinyl bond content, and a p- [N, N-bis (trimethylsilyl) amino] styrene unit and its origin. The content of the unit to be measured was measured. The results are shown in Table 2.

[Preparation of rubber composition and rubber cross-linked product]
Further, a rubber composition and a crosslinked rubber product (test piece) were obtained in the same manner as in Example 4 except that the modified conjugated diene rubber 11 obtained above was used. And the wet grip property was evaluated. The results are shown in Table 2.

Example 7
[Preparation of Modified Conjugated Diene Rubber 12]
A solid solution was obtained in the same manner as in Example 4 except that 0.4 mmol of N, N-bis (trimethylsilyl) -3-aminopropyltriethoxysilane was used instead of the polyorganosiloxane represented by the above formula (11). A modified conjugated diene rubber 12 having a shape was obtained, and the resulting modified conjugated diene rubber 12 was obtained. The weight average molecular weight (Mw), styrene unit content, vinyl bond content, and p- [N, N-bis ( The contents of trimethylsilyl) amino] styrene units and units derived therefrom were measured. The results are shown in Table 2.

[Preparation of rubber composition and rubber cross-linked product]
Further, a rubber composition and a crosslinked rubber product (test piece) were obtained in the same manner as in Example 4 except that the modified conjugated diene rubber 12 obtained above was used. And the wet grip property was evaluated. The results are shown in Table 2.

[Comparative Example 6]
[Preparation of Modified Conjugated Diene Rubber 13]
In a nitrogen atmosphere, 760 g of cyclohexane, 94.8 g of 1,3-butadiene, 25.2 g of styrene, and 1.7 g of p- [N, N-bis (trimethylsilyl) amino] styrene obtained in Production Example 1 were placed in an autoclave. Then, 0.8 mmol of n-butyllithium was added, and 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%, 0.044 mmol of tin tetrachloride was added in the form of a 20% strength cyclohexane solution, and 10 minutes. Reacted. Next, the polyorganosiloxane represented by the above formula (11) is brought into a 20% concentration xylene solution state so that the epoxy group is in an amount corresponding to 0.5 mol of n-butyllithium used. And allowed to react for 30 minutes. Thereafter, as a polymerization terminator, an amount of methanol corresponding to twice the mole of n-butyllithium used was added to obtain a solution containing the modified conjugated diene rubber 13.

Subsequently, Irganox 1520L (manufactured by Ciba Specialty Chemicals) as an anti-aging agent was added to 100 parts of the modified conjugated diene rubber 13 in the autoclave containing the solution containing the modified conjugated diene rubber 13 obtained. After adding 0.2 parts, the solvent was removed by steam stripping, followed by vacuum drying at 60 ° C. for 24 hours to obtain a solid modified conjugated diene rubber 13.

The resulting modified conjugated diene rubber 13 has a weight average molecular weight (Mw), a styrene unit content, a vinyl bond content, and a p- [N, N-bis (trimethylsilyl) amino] styrene unit and its origin. The content of the unit to be measured was measured. The results are shown in Table 2.

[Preparation of rubber composition and rubber cross-linked product]
Further, a rubber composition and a crosslinked rubber product (test piece) were obtained in the same manner as in Example 4 except that the modified conjugated diene rubber 13 obtained above was used. Similarly, low exothermic property was obtained. And the wet grip property was evaluated. The results are shown in Table 2.

[Comparative Example 7]
[Preparation of Modified Conjugated Diene Rubber 14]
A solid solution was prepared in the same manner as in Comparative Example 6 except that 0.4 mmol of N, N-bis (trimethylsilyl) -3-aminopropyltriethoxysilane was used instead of the polyorganosiloxane represented by the above formula (11). A modified conjugated diene rubber 14 having a shape was obtained. The resulting modified conjugated diene rubber 14 has a weight average molecular weight (Mw), a styrene unit content, a vinyl bond content, and a p- [N, N-bis (trimethylsilyl) amino] styrene unit content. It was measured. The results are shown in Table 2.

[Preparation of rubber composition and rubber cross-linked product]
Further, a rubber composition and a crosslinked rubber product (test piece) were obtained in the same manner as in Example 4 except that the modified conjugated diene rubber 14 obtained above was used. Similarly, low exothermic property was obtained. And the wet grip property was evaluated. The results are shown in Table 2.

[Comparative Example 8]
[Preparation of Modified Conjugated Diene Rubber 15]
Instead of 1.2 g of p- [N, N-bis (trimethylsilyl) amino] styrene obtained in Production Example 1, 1.2 g of p- (dimethylamino) styrene obtained in Production Example 2 was used. Except for the above, in the same manner as in Example 4, polymer block 2B of p- (dimethylamino) styrene (polymer in which hydrocarbyl lithium was introduced as an active terminal at the terminal of the p- (dimethylamino) styrene polymer block ) About the obtained polymer block 2B, after taking out a very small part, methanol was added to it and the thing which deactivated the active terminal was made into the sample, and the weight average molecular weight (Mw) was measured. The results are shown in Table 2.

Then, a solid modified conjugated diene rubber 15 was obtained in the same manner as in Example 4 except that the polymer block 2B thus obtained was used, and the resulting modified conjugated diene rubber 15 was obtained. , Weight average molecular weight (Mw), styrene unit content, vinyl bond content, and p- (dimethylamino) styrene unit content were measured. The results are shown in Table 2.

[Preparation of rubber composition and rubber cross-linked product]
Further, a rubber composition and a crosslinked rubber product (test piece) were obtained in the same manner as in Example 4 except that the modified conjugated diene rubber 15 obtained above was used. And the wet grip property was evaluated. The results are shown in Table 2.

[Comparative Example 9]
[Preparation of Modified Conjugated Diene Rubber 16]
Instead of 1.7 g of p- [N, N-bis (trimethylsilyl) amino] styrene obtained in Production Example 1, 1.7 g of p- (dimethylamino) styrene obtained in Production Example 2 was used. Except for the above, a solid modified conjugated diene rubber 16 was obtained in the same manner as in Comparative Example 6, and the resulting modified conjugated diene rubber 16 was weight average molecular weight (Mw), styrene unit content, vinyl bond contained. The amount and content of p- (dimethylamino) styrene units were measured. The results are shown in Table 2.

[Preparation of rubber composition and rubber cross-linked product]
A rubber composition and a crosslinked rubber product (test piece) were obtained in the same manner as in Example 4 except that the modified conjugated diene rubber 16 obtained above was used. And the wet grip property was evaluated. The results are shown in Table 2.

[Comparative Example 10]
[Preparation of Modified Conjugated Diene Rubber 17]
A solid modified conjugated diene rubber 17 was obtained in the same manner as in Comparative Example 6 except that p- [N, N-bis (trimethylsilyl) amino] styrene obtained in Production Example 1 was not used. . The resulting modified conjugated diene rubber 17 was measured for weight average molecular weight (Mw), styrene unit content, and vinyl bond content. The results are shown in Table 2.

[Preparation of rubber composition and rubber cross-linked product]
Further, a rubber composition and a crosslinked rubber product (test piece) were obtained in the same manner as in Example 4 except that the modified conjugated diene rubber 17 obtained above was used. And the wet grip property was evaluated. The results are shown in Table 2.

In Table 2, in Examples 4 to 7 and Comparative Examples 6 to 10, the evaluation results of low heat build-up and wet grip properties are shown with the result of Comparative Example 6 being 100. In Table 2, “amino group-containing monomer” means p- [N, N-bis (trimethylsilyl) amino] styrene or p- (dimethylamino) styrene. The term “body unit” means a p- [N, N-bis (trimethylsilyl) amino] styrene unit and a unit derived therefrom (p- [N, N-bis (trimethylsilyl) amino] styrene unit protecting group (trimethylsilyl group) Or a p- (dimethylamino) styrene unit.

From Table 2, the rubber cross-linked product obtained using the modified conjugated diene rubber produced by the production method of the present invention was excellent in low exothermic property and wet grip property (Examples 4 to 7).
On the other hand, the rubber cross-linked product obtained by using the modified conjugated diene rubber obtained by polymerizing the compound represented by the general formula (1) in a random manner without passing through the first step in the present invention has a low exothermic property. It was inferior to both wet grip properties (Comparative Examples 6 and 7).
Furthermore, a modified conjugated diene rubber produced using an amino group-containing compound different from the compound represented by the general formula (1), or a modified conjugated diene system produced without using an amino group-containing compound The crosslinked rubber obtained using rubber was also inferior in both low heat build-up and wet grip properties (Comparative Examples 8 to 10).

Examples 5 and 6 are examples in which the same operation was performed except that deprotection was performed using a tetrabutylammonium fluoride / tetrahydrofuran solution. 5 and Example 6 are equivalent in the results of low exothermic property and wet grip property. Therefore, the deprotection in the polymer block composed of the compound represented by the general formula (1) prepared a rubber composition. This is also considered to occur during the kneading by the Brabender type mixer, and this is also considered to be the same in Examples 1 to 3 described above. In addition, it is thought that this reason is because the stearic acid mix | blended as a compounding agent is acting during the kneading | mixing by a Brabender type mixer, for example.

Claims

A first step of polymerizing a compound represented by the following general formula (1) using a polymerization initiator to obtain a polymer block of the compound represented by the general formula (1) having an active end;
And a second step of polymerizing a monomer comprising at least a conjugated diene compound from an active end of the polymer block.

(In the general formula (1), R 1 is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and at least one of X 1 and X 2 is a protecting group for an amino group.)
The method for producing a conjugated diene rubber according to claim 1, wherein the amino-protecting group is a group represented by the following general formula (2).

(In the above general formula (2), R 2 to R 4 are each independently a group selected from a hydrogen atom and an optionally substituted hydrocarbon group having 1 to 18 carbon atoms. )
The compound represented by the general formula (1) is p- [N, N-bis (trimethylsilyl) amino] styrene or p- [N, N-bis (trimethylsilyl) amino] -α-methylstyrene. A method for producing a conjugated diene rubber according to claim 1 or 2.
The method for producing a conjugated diene rubber according to any one of claims 1 to 3, wherein a monomer containing 0 to 50% by weight of an aromatic vinyl compound is used as the monomer.
A conjugated diene rubber obtained by the production method according to any one of claims 1 to 4.
A first step of polymerizing a compound represented by the following general formula (1) using a polymerization initiator to obtain a polymer block of the compound represented by the general formula (1) having an active end;
A second step of polymerizing a monomer comprising at least a conjugated diene compound from an active end of the polymer block;
A third step of reacting the active end of the polymer chain of the conjugated diene rubber obtained in the second step with a silane compound having a functional group capable of reacting with the active end, and manufacturing a modified conjugated diene rubber Method.

(In the general formula (1), R 1 is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and at least one of X 1 and X 2 is a protecting group for an amino group.)
The method for producing a modified conjugated diene rubber according to claim 6, wherein the amino-protecting group is a group represented by the following general formula (2).

(In the above general formula (2), R 2 to R 4 are each independently a group selected from a hydrogen atom and an optionally substituted hydrocarbon group having 1 to 18 carbon atoms. )
The compound represented by the general formula (1) is p- [N, N-bis (trimethylsilyl) amino] styrene or p- [N, N-bis (trimethylsilyl) amino] -α-methylstyrene. A method for producing a modified conjugated diene rubber according to claim 6 or 7.
A modified conjugated diene rubber obtained by the production method according to any one of claims 6 to 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 conjugated diene rubber according to claim 5 or the modified conjugated diene rubber according to claim 9.
The rubber composition according to claim 10, further comprising a crosslinking agent.
A crosslinked rubber product obtained by crosslinking the rubber composition according to claim 11.
A tire comprising the rubber cross-linked product according to claim 12.