WO2018088483A1

WO2018088483A1 - Method for producing modified conjugated diene rubber

Info

Publication number: WO2018088483A1
Application number: PCT/JP2017/040454
Authority: WO
Inventors: 英順植田; 山岸　英哲; 岸本　典久
Original assignee: 日本ゼオン株式会社
Priority date: 2016-11-14
Filing date: 2017-11-09
Publication date: 2018-05-17
Also published as: JPWO2018088483A1; JP7020423B2

Abstract

Provided is a method for producing a modified conjugated diene rubber, the method comprising a first step for polymerizing, in an inert solvent, a monomer containing at least a conjugated diene compound by using an organic active metal compound as a polymerization initiator to obtain a conjugated diene polymer having an active end, and a second step for reacting a compound represented by general formula (1) with the active end of said conjugated diene polymer having the active end. (In general formula (1), R¹ and R³ each independently represent a monovalent hydrocarbon group, a hydrogen atom, or a hydroxy group, R² represents an arbitrary defined organic group, a hydrogen atom, or a hydroxy group, X¹ represents a protected amino group-containing organic group containing a primary amino group protected by a protecting group, m represents an integer of 1-30, n represents an integer of 0-29, and m+n is 3-30.)

Description

Process for producing modified conjugated diene rubber

The present invention relates to a method for producing a modified conjugated diene rubber, and more particularly to a method for producing a modified conjugated diene rubber capable of giving a rubber cross-linked product excellent in wet grip properties and low heat build-up. The present invention also relates to a modified conjugated diene rubber obtained by this production method, a rubber composition containing the modified conjugated diene rubber, and a crosslinked rubber product thereof.

In recent years, there has been a strong demand for low heat build-up for automobile tires due to environmental problems and resource problems, and from the viewpoint of safety, excellent wet grip properties are also demanded. 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. However, on the other hand, even if silica is blended with the rubber that is usually used, it is inferior in affinity with silica, so separation is likely to occur, and as a result, low heat build-up and wet grip properties cannot be improved. There was a problem.

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

For example, in Patent Document 1, a compound having a protected primary amino group and an alkoxysilyl group such as N, N-bis (trimethylsilyl) aminopropylmethyldimethoxysilane is reacted with the active terminal of a conjugated diene polymer. Therefore, attempts have been made to increase the affinity between the conjugated diene polymer and silica. In the technique of Patent Document 1, the resulting conjugated diene polymer has a certain degree of affinity for silica, but the dispersibility of silica when blended with silica is not always sufficient, and therefore, the wet grip The improvement effect of heat resistance and low exothermicity was also limited.

JP 2004-67982 A

The present invention has been made in view of such a situation, and provides a method for producing a modified conjugated diene rubber that can give a crosslinked rubber excellent in wet grip and low heat build-up. With the goal.

In order to achieve the above object, the present inventors have conducted extensive studies on a modifier for modifying the active terminal of a conjugated diene polymer. As a result, the modifier has a cyclic siloxane structure and is protected. Modified conjugated diene rubber obtained by using a specific silane compound with an amino group-containing organic group and reacting this with the active end of a conjugated diene polymer having an active end is good for fillers such as silica. It was found that a rubber cross-linked product excellent in wet grip properties and low heat build-up properties can be obtained, and the present invention has been completed.

That is, according to the present invention, a conjugated diene polymer having an active terminal is obtained by polymerizing a monomer comprising at least a conjugated diene compound using an organic active metal compound as a polymerization initiator in an inert solvent. And a second step of reacting a compound represented by the following general formula (1) with the active terminal of the conjugated diene polymer having the active terminal: A method is provided.

(In the general formula (1), R ¹ and R ³ are each independently a monovalent hydrocarbon group, a hydrogen atom or a hydroxyl group, and R ² is an arbitrary organic group, a hydrogen atom or a hydroxyl group, X ¹ is a protected amino group-containing organic group containing a primary amino group protected by a protecting group, m is an integer of 1 to 30, n is an integer of 0 to 29, and m + n is 3 to 30 is there.)

In the present invention, the compound represented by the general formula (1) is preferably a compound represented by the following general formula (2).

(In the general formula (2), R ¹ , R ⁴ to R ⁶ are each independently a monovalent hydrocarbon group, a hydrogen atom or a hydroxyl group, and X ¹ is a ^primary group protected by a protecting group. A protected amino group-containing organic group containing an amino group, X ² is an alkoxy group-containing organic group or an epoxy group-containing organic group, m is an integer of 1 to 29, p is an integer of 1 to 29, and q is 0 (It is an integer of ~ 28, and m + p + q is 3 to 30.)
In the compound represented by the general formula (2), the content ratio of the protected amino group-containing organic group to the alkoxy group-containing organic group and / or the epoxy group-containing organic group is expressed as “protected amino group-containing organic group / ( The molar ratio of “alkoxy group-containing organic group and / or epoxy group-containing organic group” ”is preferably 0.1 to 10.

In the present invention, the compound represented by the general formula (1) is represented by the following general formula (3), the following general formula (4), or the following general formula (5) as the protected amino group-containing organic group. It is preferable that it contains a group.

(In the general formula (3), R ⁷ to R ¹⁰ are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and e is an integer of 1 to 12) F is an integer from 1 to 12.)

(In the general formula (4), R ¹¹ to R ¹⁶ are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and g is an integer of 1 to 12) .)

(In the general formula (5), R ¹⁷ and R ¹⁸ are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and h is an integer of 1 to 12) .)

In the present invention, the amount of the compound represented by the general formula (1) is preferably 0.01 to 30 moles relative to 1 mole of the organic active metal as a polymerization initiator, More preferably, it is ˜5 mol.

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

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

According to the present invention, a modified conjugated diene rubber capable of giving a rubber cross-linked product excellent in wet grip properties and low heat build-up properties, a rubber composition containing the modified conjugated diene rubber, and the rubber composition are cross-linked. It is possible to provide a rubber cross-linked product excellent in wet grip and low heat build-up, and a tire comprising the rubber cross-linked product.

<Method for producing modified conjugated diene rubber>
The method for producing a modified conjugated diene rubber according to the present invention has an active terminal by polymerizing a monomer containing at least a conjugated diene compound using an organic active metal compound as a polymerization initiator in an inert solvent. A first step of obtaining a conjugated diene polymer, and a second step of reacting the active terminus of the conjugated diene polymer having the active terminus with a compound represented by the general formula (1) described later.

<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, a monomer comprising at least a conjugated diene compound is polymerized in an inert solvent using an organic active metal compound as a polymerization initiator, and a conjugated diene having an active terminal is obtained. This is a step of obtaining a polymer.

In the first step, the conjugated diene compound used for polymerization in order to obtain a conjugated diene polymer having an active terminal is not particularly limited, and for example, 1,3-butadiene, isoprene, 2,3-dimethyl-1 , 3-butadiene, 1,3-pentadiene, 2-methyl-3-ethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 1,3-cyclohexadiene, etc. Can be mentioned. Of these, 1,3-butadiene, isoprene and 1,3-pentadiene are preferred, and 1,3-butadiene and isoprene are particularly preferred. In addition, these conjugated diene compounds may be used individually by 1 type, and may be used in combination of 2 or more type.

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

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

The inert solvent used in the first step of the production method of the present invention is not particularly limited as long as it is usually used in solution polymerization and 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. These inert solvents may be used individually by 1 type, and may be used in combination of 2 or more type. The amount of the inert solvent used is such that the monomer concentration is, for example, 1 to 50% by weight, preferably 10 to 40% by weight.

The organic active metal compound used as a polymerization initiator is not particularly limited as long as it can polymerize a monomer containing a conjugated diene compound to give a conjugated diene polymer having an active terminal, As a specific example, a polymerization initiator mainly comprising 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, t-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-t-butoxystrontium, diethoxybarium, and diisopropoxybarium. Diethyl mercaptobarium, di-t-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.

The amount of the organic active metal compound used as the polymerization initiator may be determined according to the molecular weight of the target polymer, but is usually 1 to 50 mmol, preferably 1.5 to 20 per 1000 g of monomer. In the range of millimolar, more preferably 2-15 millimolar.

The polymerization temperature in the first step of the production method of the present invention is usually in the range of −80 to + 150 ° C., preferably 0 to 100 ° C., more preferably 30 to 90 ° C. As the polymerization mode, any of batch type and continuous type can be adopted. However, when copolymerizing a conjugated diene compound and an aromatic vinyl compound, a conjugated diene monomer unit and an aromatic vinyl monomer are used. The batch method is preferred because it is easy to control the randomness of the bond with the unit.

In the production method of the present invention, when the conjugated diene polymer having an active terminal is composed of two or more types of monomer units, there are various bonding modes such as a block shape, a taper shape, and a random shape. However, a random binding mode is preferred. By making it random, the resulting rubber cross-linked product is excellent in low heat build-up.

In the production method of the present invention, in order to adjust the vinyl bond content in the conjugated diene monomer unit in the conjugated diene polymer having an active terminal, a polar compound is added to the inert organic solvent during the polymerization. It is preferable to do. 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, tertiary amines are more preferable, and tetramethylethylenediamine is particularly preferable. 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 may be determined according to the target vinyl bond content, and is preferably 0.001 to 100 mol, more preferably 0, relative to 1 mol of the organic active metal compound used as the polymerization initiator. .01 to 10 moles. 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 deactivation of the polymerization initiator hardly occur.

As described above, according to the first step in the production method of the present invention, a conjugated diene polymer having an active terminal can be obtained by polymerizing a monomer containing a conjugated diene compound.

The vinyl bond content in the conjugated diene monomer unit in the conjugated diene polymer having an active end obtained in the first step of the production method of the present invention is preferably 1 to 90 mol%, more preferably 5 ~ 85 mol%. When the vinyl bond amount is in the above range, the resulting rubber cross-linked product has excellent low heat build-up.

The peak top molecular weight detected by gel permeation chromatography (hereinafter also referred to as GPC) of the conjugated diene polymer having an active terminal obtained in the first step of the production method of the present invention is 10 in terms of polystyrene. It is preferably from 1,000,000 to 1,000,000, more preferably from 50,000 to 850,000, and particularly preferably from 100,000 to 700,000. When a plurality of peaks of the conjugated diene polymer are observed, the peak top molecular weight of the peak having the smallest molecular weight derived from the conjugated diene polymer detected by GPC is used as the conjugated diene polymer having an active end. The peak top molecular weight of When the peak top molecular weight of the conjugated diene polymer having an active end is in the above range, the resulting rubber cross-linked product is excellent in low heat build-up.

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 polymer having an active end obtained in the first step of the production method of the present invention is: Preferably it is 1.0 to 1.5, more preferably 1.0 to 1.4, and particularly preferably 1.0 to 1.3. When this molecular weight distribution value (Mw / Mn) is in the above range, the resulting rubber cross-linked product is excellent in low heat build-up.

<Second step>
Next, the second step in the production method of the present invention will be described. In the second step of the production method of the present invention, the compound represented by the following general formula (1) is reacted with the active end of the conjugated diene polymer having the active end obtained in the first step. In this step, a modified conjugated diene rubber is obtained.

In the production method of the present invention, the conjugated diene is reacted by reacting the compound represented by the general formula (1) with the active terminus of the conjugated diene polymer having an active terminus obtained in the first step. System rubber can be modified to improve the affinity for silica and other fillers, and when silica and other fillers are blended, the dispersibility of silica and other fillers can be increased. And a rubber cross-linked product having wet grip properties.

In the general formula (1), m is an integer of 1 to 30, preferably an integer of 1 to 20, more preferably an integer of 1 to 10. n is an integer of 0 to 29, preferably an integer of 0 to 20, and more preferably an integer of 0 to 10. M + n is 3 to 30, preferably 3 to 20, and more preferably 3 to 10.

In the general formula (1), X ¹ is a protected amino group-containing organic group containing a primary amino group protected by a protecting group (hereinafter, also simply referred to as “protected amino group-containing organic group”). The protected amino group-containing organic group is not particularly limited as long as it has a structure in which a protective group is introduced into the amino group, and the two hydrogen atoms of the primary amino group (ie, —NH ₂ ) It is preferably a group containing a protected amino group having a structure substituted with a group acting as a protecting group. Such a protecting group is not particularly limited, but is preferably one capable of introducing an inactive structure with respect to the active end of the conjugated diene polymer having an active end obtained in the first step. Examples of such a protecting group include a hydrocarbyl group or a silyl group, and a silyl group is preferable. Moreover, as a protecting group, in addition to being capable of introducing an inactive structure to the active end of the conjugated diene polymer having an active end obtained in the first step, an acid or a base is used. More preferably, it can be deprotected by a method or a hydrolysis reaction. When the protecting group is deprotectable, the protected amino group-containing organic group contains a primary amino group or a secondary amino group by deprotecting the protecting group. Thus, it is considered that the affinity with fillers such as silica can be further increased.

Suitable examples of such a protected amino group-containing organic group include groups represented by the following general formula (3), the following general formula (4), or the following general formula (5). In the general formula (1), when m is 2 or more, a plurality of X ¹ are present, but the plurality of protected amino group-containing organic groups may be the same as or different from each other.

(In the general formula (3), R ⁷ to R ¹⁰ are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms. E is an integer of 1 to 12, preferably an integer of 1 to 6, more preferably an integer of 1 to 4. f is an integer of 1 to 12, and preferably an integer of 1 to 6 More preferably, it is an integer of 1 to 4.)

(In the general formula (4), R ¹¹ to R ¹⁶ are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms. (G is an integer of 1 to 12, preferably an integer of 1 to 6, more preferably an integer of 1 to 4.)

(In the general formula (5), R ¹⁷ and R ¹⁸ are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms. H is an integer of 1 to 12, preferably an integer of 1 to 6, more preferably an integer of 1 to 4.)

In the group represented by the general formula (3), a group represented by —SiR ⁷ R ⁸ — (CH ₂ ) _f —SiR ⁹ R ¹⁰ — acts as a protecting group. Similarly, in the group represented by the general formula (4), a group represented by —SiR ¹¹ R ¹² R ¹³ and a group represented by —SiR ¹⁴ R ¹⁵ R ¹⁶ act as a protecting group. In the group represented by the general formula (5), the group represented by R ¹⁷ and the group represented by R ¹⁸ act as protective groups.

As the protected amino group-containing organic group, those having a silyl group as the protecting group are preferable from the viewpoint that they function well as a protecting group and can also perform a deprotection reaction well, and are represented by the above formula (3). The group and the group represented by the above formula (4) are preferable.

Specific examples of the protected amino group constituting the protected amino group-containing organic group include bis (trimethylsilyl) amino group, bis (triethylsilyl) amino group, bis (triisopropylsilyl) amino group, and bis (triphenylsilyl) amino group. Bis (dimethylphenylsilyl) amino group, bis (t-butyldimethylsilyl) amino group, bis (t-butyldiphenylsilyl) amino group, 2,2,5,5-tetramethyl-1,2,5-azadisilolidine Group, bis (di-t-butylmethylsilyl) amino group, bis (di-t-butylisobutylsilyl) amino group and the like.

In the general formula (1), R ¹ and R ³ are each independently a monovalent hydrocarbon group, a hydrogen atom or a hydroxyl group, preferably a monovalent hydrocarbon group. The monovalent hydrocarbon group is preferably an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, and further preferably a methyl group. It is. R ² is an arbitrary organic group, a hydrogen atom or a hydroxyl group, and examples of the arbitrary organic group include an alkoxy group-containing organic group, an epoxy group-containing organic group, and a monovalent hydrocarbon group. Incidentally, in the general formula (1), when n is 2 or more, but so that the R ² there are a plurality, the plurality of R ² may be different and the same as each other.

Further, as the compound represented by the general formula (1), the modification effect of the conjugated diene rubber, specifically, the affinity for the filler such as silica is improved, and the filler such as silica is blended. At the time, the effect of enhancing the dispersibility of fillers such as silica is high, and thereby, the resulting rubber cross-linked product can be made more excellent in low exothermic property and wet grip property, from the following general formula The compound represented by (2) is preferred.

(In the general formula (2), R ¹ , R ⁴ to R ⁶ are each independently a monovalent hydrocarbon group, a hydrogen atom or a hydroxyl group, and X ¹ is a ^primary group protected by a protecting group. A protected amino group-containing organic group containing an amino group, X ² is an alkoxy group-containing organic group or an epoxy group-containing organic group, m is an integer of 1 to 29, p is an integer of 1 to 29, and q is 0 (It is an integer of ~ 28, and m + p + q is 3 to 30.)

In the general formula (2), m is an integer of 1 to 29, preferably an integer of 1 to 20, and more preferably an integer of 1 to 10. p is an integer of 1 to 29, preferably an integer of 1 to 20, more preferably an integer of 1 to 10, and q is an integer of 0 to 28, preferably an integer of 0 to 20, more preferably It is an integer of 0 to 10, particularly preferably 0. Further, m + p + q is 3 to 30, preferably 3 to 20, and more preferably 3 to 10.

In the above general formula (2), X ¹ is the same as the above general formula (1), and the preferred embodiment is also the same as the above general formula (1).

Further, in the above general formula (2), X ² is an alkoxy group-containing organic group or an epoxy group-containing organic group is preferably an alkoxy group-containing organic group. Incidentally, in the general formula (2), when p is 2 or more, but so that the X ² there are a plurality, the plurality of X ² may be different and the same as each other.

The alkoxy group-containing organic group may be any group that contains an alkoxy group, and is not particularly limited. Examples of the alkoxy group include alkoxy groups such as a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, and a butoxy group, Examples include alkoxysilyl groups, but it is possible to improve the coupling ratio of two or more branches in the resulting modified conjugated diene rubber, thereby further improving wet grip and low heat build-up. From the standpoint, those containing an alkoxysilyl group are preferred. In addition, it is thought that an alkoxy group-containing organic group usually acts as a binding site that binds to a conjugated diene polymer having an active end.

The alkoxysilyl group-containing organic group is not particularly limited as long as it is a group containing an alkoxysilyl group, and the alkoxysilyl group contains any of a monoalkoxysilyl group, a dialkoxysilyl group, or a trialkoxysilyl group. For example, a group represented by the following general formula (6) may be mentioned.

In the general formula (6), R ¹⁹ each independently represents an alkyl group having 1 to 20 carbon atoms, preferably an alkyl group having 1 to 10 carbon atoms, and R ²⁰ represents a hydrogen atom or a carbon number. An alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an allyloxy group having 6 to 20 carbon atoms, or a halogen atom. j is an integer of 1 to 20, preferably an integer of 2 to 15, more preferably an integer of 3 to 10, and k is an integer of 1 to 3. Incidentally, when k is 2 or 3, R ¹⁹ is a presence of a plurality, the plurality of R ¹⁹ may be different be the same as each other. Similarly, when k is 1, R ²⁰ is a presence of a plurality, the plurality of R ²⁰ may be different be the same as each other.

Specific examples of the alkoxysilyl group contained in the alkoxysilyl group-containing organic group include a trialkoxysilyl group such as a trimethoxysilyl group and a triethoxysilyl group; a dimethoxymethylsilyl group, a diethoxymethylsilyl group, a dimethoxyethylsilyl group, Dialkoxyalkylsilyl groups such as diethoxyethylsilyl group; monoalkoxydialkyl groups such as methoxydimethylsilyl group, ethoxydimethylsilyl group, methoxydiethylsilyl group, ethoxydiethylsilyl group; and the like. Among these, when used as a polymer modifier, for example, when used as a polymer modifier, it is possible to increase the affinity between the polymer and a filler such as silica. The trialkoxysilyl group is preferable and the trimethoxysilyl group is more preferable from the viewpoint that the effect of improving the resistance is high.

The epoxy group-containing organic group is not particularly limited as long as it is an organic group containing an epoxy group, but is not limited to 2-glycidoxyethyl group, 3-glycidoxypropyl group, 4-glycidoxybutyl group. A glycidoxyalkyl group such as 2- (3,4-epoxycyclohexyl) ethyl group, 3- (3,4-epoxycyclohexyl) propyl group, 2- (3,4-epoxynorbornyl) ethyl group, 2 -Epoxycycloalkylalkyl groups such as (3,4-epoxy-3-methylcyclohexyl) -2-methylethyl group; oxiranylalkyl groups such as 4-oxiranylbutyl group and 8-oxiranyloctyl group; Etc. Among these, a glycidoxyalkyl group is preferable, and a 3-glycidoxypropyl group is particularly preferable.

R ¹ and R ⁴ to R ⁶ are each independently a monovalent hydrocarbon group, a hydrogen atom or a hydroxyl group, preferably a monovalent hydrocarbon group. The monovalent hydrocarbon group is preferably an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, and further preferably a methyl group. It is.

In the compound represented by the general formula (2), the content ratio of the protected amino group-containing organic group and the alkoxy group-containing organic group and / or the epoxy group-containing organic group is not particularly limited. The molar ratio of “group-containing organic group / (alkoxy group-containing organic group and / or epoxy group-containing organic group)” is preferably 0.1 to 10.0, more preferably 0.2 to 5.0, Preferably it is 0.25 to 4.0, and particularly preferably 0.5 to 1.5. By setting the content ratio of the protected amino group-containing organic group, the alkoxy group-containing organic group and / or the epoxy group-containing organic group to the above range, the wet grip property and low heat build-up property of the resulting rubber cross-linked product are more appropriately improved. Can be increased.

Moreover, as a compound represented by the said General formula (1), you may use what mixed multiple compounds which have a mutually different structure. That is, for example, a mixture of a compound with m = 2 and m + n = 4 and a compound with m = 2 and m + n = 5 may be used, or m = 2 and m + n = 4. A mixture of two or more compounds having different X ¹ may be used. Furthermore, m = 2, m + n = 4, and two or more compounds having different X ¹ and m = 2, m + n = 5, two or more compounds having different X ¹ are mixed. Also good.

Moreover, in the manufacturing method of this invention, the usage-amount of the compound represented by the said General formula (1) in a 2nd process is the organic active metal compound as a polymerization initiator used in the 1st process mentioned above. The ratio is preferably 0.01 to 30 moles, more preferably 0.05 to 5 moles, and further preferably 0.1 to 3 moles per mole of metal atoms. preferable. By making the usage-amount of the compound represented by the said General formula (1) into the said range, in the modified conjugated diene rubber obtained by a 2nd process, the said General formula (1) taken in by the modified conjugated diene rubber The ratio of the compound represented by (II) can be made appropriate, whereby the wet grip property and the low heat build-up can be improved more appropriately when a rubber cross-linked product is obtained.

In the present invention, as a modifier used when producing a modified conjugated diene rubber, a cyclic main chain structure composed of repeating units represented by —Si—O— as shown in the general formula (1) is used. The compound which has is used. According to the present invention, by using such a compound having a cyclic main chain structure composed of repeating units represented by —Si—O—, the effect of introducing a modified structure introduced by a modifier, ie, the above-described effect The effect of the protected amino group-containing organic group can be made sufficient. And thereby, the effect of improving the affinity for fillers such as silica can be made more satisfactory, and as a result, the obtained rubber cross-linked product is excellent in wet grip and low heat build-up. Is something that can be done.

In the second step of the production method of the present invention, as a method of reacting the compound represented by the general formula (1) with the active end of the conjugated diene polymer having the active end obtained in the first step described above. Is not particularly limited, but the conjugated diene polymer having an active end obtained in the first step described above and the compound represented by the general formula (1) in a solvent capable of dissolving them, The method of mixing etc. is mentioned. As the solvent used at this time, those exemplified as the solvent used for the polymerization of the conjugated diene polymer described above can be used. In this case, the conjugated diene polymer having an active end obtained in the first step described above is kept in the polymerization solution used for the polymerization, and is represented by the general formula (1). The method of adding the compound is simple and preferred. In this case, the compound represented by the general formula (1) is preferably dissolved in the inert solvent used for the polymerization and added to the polymerization system, and the solution concentration is 1 to 50. It is preferable to set it as the range of weight%. The reaction temperature in the second step is not particularly limited, but is usually 0 to 120 ° C., and the reaction time is not particularly limited, but is usually 1 minute to 1 hour.

The timing of adding the compound represented by the general formula (1) to the solution containing the conjugated diene polymer having an active terminal is not particularly limited, but the polymerization reaction is not completed and the conjugate having an active terminal is present. The state in which the solution containing the diene polymer also contains a monomer, more specifically, the solution containing the conjugated diene polymer having an active terminal is 100 ppm or more, more preferably 300 to 50. It is desirable to add the compound represented by the general formula (1) to this solution in a state containing 1,000 ppm of monomer. By adding the compound represented by the general formula (1) in this way, side reactions between the conjugated diene polymer having an active terminal and impurities contained in the polymerization system are suppressed, and the reaction is performed. It becomes possible to control well.

Before reacting the compound represented by the general formula (1) with the conjugated diene polymer having an active end, the active end of the conjugated diene polymer is not limited so long as the effect of the present invention is not inhibited. The part may be inactivated by adding a coupling agent, a modifier and the like conventionally used in the polymerization system.

When the compound represented by the general formula (1) is reacted with a conjugated diene polymer having an active end, and an unreacted active end remains, an alcohol such as methanol, ethanol, isopropanol, or water It is preferable to deactivate the unreacted active terminal by adding a polymerization terminator or the like to the polymerization solution.

An anti-aging agent such as a phenol-based stabilizer, a phosphorus-based stabilizer, or a sulfur-based stabilizer may be added to the modified conjugated diene rubber solution obtained as described above, if desired. What is necessary is just to determine suitably the addition amount of an anti-aging agent according to the kind etc. Furthermore, if desired, an extension oil may be blended to form an oil-extended rubber. Examples of 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 modified conjugated diene rubber.

The modified conjugated diene rubber after the modification reaction thus obtained is separated from the reaction mixture by removing the solvent by steam stripping to obtain a solid modified conjugated diene rubber. be able to. In this case, the protected amino group-containing organic compound derived from the compound represented by the above general formula (1) introduced into the modified conjugated diene rubber after the modification reaction as described above by steam stripping. It is considered that a primary amino group or a secondary amino group is generated by deprotecting the protecting group in the group by hydrolysis.

The modified conjugated diene rubber obtained by the production method of the present invention contains the compound represented by the general formula (1) or a structure forming a coupling structure having two or more branches via a coupling agent. The modified conjugated diene rubber preferably has a content ratio (coupling ratio) of the structure forming a coupling structure having two or more branches of the compound represented by the general formula (1). Is 5% by weight or more, more preferably 8% by weight or more, and still more preferably 10% by weight or more. When the content ratio of the structure forming a coupling structure having two or more branches is in the above-mentioned range, the effect of improving wet grip properties and low heat build-up becomes more remarkable, which is preferable.

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

Further, the molecular weight distribution represented by the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the modified conjugated diene rubber obtained by the production method of the present invention is not particularly limited. Is 1.0 to 5.0, particularly preferably 1.0 to 3.0. By setting the molecular weight distribution of the modified conjugated diene rubber within the above range, the resulting rubber cross-linked product becomes more excellent due to low heat build-up.

The Mooney viscosity (ML _{1 + 4,} 100 ° C.) of the modified conjugated diene rubber obtained by the production method of the present invention is also not particularly limited, but is usually in the range of 20 to 200, preferably 30 to 150. By setting the Mooney viscosity of the modified conjugated diene rubber to the above range, the processability of the rubber composition becomes excellent. When the modified conjugated diene rubber is an oil-extended rubber, the Mooney viscosity of the oil-extended rubber is preferably in the above range.

The modified conjugated diene rubber thus obtained can be suitably used for various applications after adding compounding agents such as a filler and a crosslinking agent. In particular, when silica is blended as a filler, a rubber composition suitably used for obtaining a crosslinked rubber product having excellent wet grip properties and low heat build-up properties is provided.

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

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

The compounding amount of silica in the rubber composition of the present invention is 10 to 200 parts by weight, preferably 30 to 150 parts by weight, more preferably 50 to 100 parts by weight with respect to 100 parts by weight of the rubber component in the rubber composition. Part. By setting the blending amount of silica in the above range, the processability of the rubber composition becomes excellent, and the 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) prol) tetrasulfide, γ-trimethoxysilylpropyldimethylthiocarbamyl tetrasulfide, and γ -Trimethoxysilylpropylbenzothiazyl tetrasulfide and the like. These silane coupling agents can be used alone or in combination of two or more. The amount of the silane coupling agent is preferably 0.1 to 30 parts by weight, more preferably 1 to 15 parts by weight with respect to 100 parts by weight of silica.

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

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

The rubber composition of the present invention preferably further contains a cross-linking agent. Examples of the crosslinking agent include sulfur-containing compounds such as sulfur and sulfur halides, organic peroxides, 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 rubber other than the modified conjugated diene rubber obtained by the production method of the present invention described above. Examples of other rubbers include natural rubber, polyisoprene rubber, emulsion polymerization styrene-butadiene copolymer rubber, solution polymerization styrene-butadiene copolymer rubber, and polybutadiene rubber (high cis-BR and low cis BR). Further, it may 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- Of butadiene copolymer rubber, acrylonitrile-styrene-butadiene copolymer rubber, etc., those other than the above-mentioned modified conjugated diene rubber. Of these, natural rubber, polyisoprene rubber, polybutadiene rubber, and solution-polymerized styrene-butadiene copolymer rubber are preferable. These rubbers can be used alone or in combination of two or more.

In the rubber composition of the present invention, the modified conjugated diene rubber obtained by the production method of the present invention preferably occupies 10 to 100% by weight of the rubber component in the rubber composition, and occupies 50 to 100% by weight. Is particularly preferred. By including the modified conjugated diene rubber obtained by the production method of the present invention in the rubber component at such a ratio, it is possible to obtain a crosslinked rubber product having low heat build-up and excellent wet grip properties.

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

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

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

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

The rubber cross-linked product of the present invention thus obtained is obtained by using the modified conjugated diene rubber obtained by the above-described production method of the present invention, and therefore has excellent wet grip properties and low heat build-up properties. It is. In particular, the modified conjugated diene rubber obtained by the production method of the present invention is obtained by using the compound represented by the above general formula (1) as a modifier. In addition, it has a high affinity for fillers such as silica, and it can disperse fillers such as silica well. 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 excellent wet grip properties and low heat build-up properties.

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 wet grip properties and low heat build-up 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 and coupling rate of modified conjugated diene rubber]
The molecular weight of the rubber was determined as a molecular weight in terms of polystyrene by gel permeation chromatography. Specific measurement conditions were as follows.
Measuring instrument: High-performance liquid chromatograph (trade name “HLC-8220” manufactured by Tosoh Corporation)
Column: manufactured by Tosoh Corporation, two product names “GMH-HR-H” were connected in series.
Detector: differential refractometer (trade name “RI-8220” manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Column temperature: 40 ° C
For the coupling rate, the area ratio of the peak portion having a peak top molecular weight of 1.9 times or more of the peak top molecular weight indicated by the peak derived from the polymer having the smallest molecular weight relative to the total elution area is obtained from the obtained chart. The coupling rate of the branched conjugated diene rubber was 2 or more branches (content ratio of 2 or more branched structures).

[Low heat generation]
For a test piece having a length of 50 mm, a width of 12.7 mm, and a thickness of 2 mm, a viscoelasticity measuring device (manufactured by Rheometrics, product name “ARES”) is used, and the dynamic strain is 2.5% and 10 Hz. Tan δ at 0 ° C. was measured. The value of tan δ is indicated by an index with the measured value of Comparative Example 1 being 100. The larger this index, the better the low heat buildup.

[Wet grip]
For a test piece having a length of 50 mm, a width of 12.7 mm, and a thickness of 2 mm, a viscoelasticity measuring device (manufactured by Rheometrics, product name “ARES”) was used, and the dynamic strain was 0.5% and 10 Hz. Tan δ at 0 ° C. was measured. The value of tan δ is indicated by an index with the measured value of Comparative Example 1 being 100. The larger this index, the better the wet grip.

[Example 1]
[Production of denaturant 1]
The reactor was charged with 31.8 g of methylhydrogencyclosiloxane represented by the following formula (7) and heated to 40 ° C. with stirring under a nitrogen stream.

Next, 1.3 g of a toluene solution of platinum-1,3-divinyl-1,3-dimethyldisiloxane complex (Pt concentration 0.17 wt%) was added, and 1-allyl-2,2 ′, 5,5′- 52.8 g of tetramethyl- (1-aza-2,5-disilacyclopentane) was added dropwise so as to keep the reaction temperature at 40 to 75 ° C. After completion of the dropping, stirring was continued at 70 to 75 ° C. for 1 hour, and then 0.5 g of the reaction solution was sampled, and an alkali decomposition gas generation method (remaining Si—H group was decomposed with KOH ethanol / water solution to generate hydrogen generated). The reaction rate was confirmed to be about 50% by calculating the reaction rate from the gas volume). Next, 74.8 g of 5-hexenyltrimethoxysilane was added dropwise so as to keep the reaction temperature at 70 to 80 ° C. After completion of dropping, 0.4 g of a toluene solution of platinum-1,3-divinyl-1,3-dimethyldisiloxane complex (Pt concentration 0.17 wt%) was added, and stirring was continued at 80 ° C. for 1 hour. 0.5 g of the reaction solution was sampled and it was confirmed that the reaction was completed by an alkali decomposition gas generation method. The reaction solution was heated to 155 ° C. under reduced pressure to distill off the low boiling point for 3 hours, and 134.3 g of the modifier 1 represented by the following formula (8) was obtained. The structure represented by the following formula (8) was also confirmed by ¹ H-NMR. The viscosity of the obtained modifier 1 was 230 mm ² / s as measured according to JIS-Z-8803 at 25 ° C. using an Ubbelohde viscosity tube.

[Production of Modified Conjugated Diene Rubber 1]
In a nitrogen atmosphere, charge 800 parts of cyclohexane, 94.8 parts of 1,3-butadiene, 25.2 parts of styrene, and 0.187 parts of tetramethylethylenediamine, and then add 0.045 part of n-butyllithium to the autoclave. Then, polymerization was started at 60 ° C. The polymerization reaction was continued for 60 minutes, and after confirming that the polymerization conversion rate was in the range of 95% to 100%, the modifier 1 obtained above (compound represented by the above formula (8)) 1.35 parts (1.50 moles relative to the amount of n-butyl lithium used) were added and reacted for 30 minutes, and then 0.064 parts of methanol was added as a polymerization terminator to give a conjugated diene series. A solution containing the polymer was obtained. Then, 100 parts of the obtained polymer component was treated with 2,4-bis [(octylthio) methyl] -o-cresol (trade name “Irganox 1520” manufactured by Ciba Specialty Chemicals) as an anti-aging agent. After adding 15 parts to the solution, 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 1. The resulting modified conjugated diene rubber 1 had a weight average molecular weight (Mw) of 478,000, and a coupling ratio of two or more branches was 38.3% by weight.

[Production 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 1 obtained above was masticated for 30 seconds, then 50 parts of silica (trade name “Zeosil 1165MP”, manufactured by Rhodia), and process oil ( 20 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 0.0 part was added and kneaded for 1.5 minutes starting at 110 ° C., then 25 parts of silica (trade name “Zeosil 1165MP”, manufactured by Rhodia), 3 parts of zinc oxide, 2 parts of stearic acid, and an antioxidant: N-phenyl-N ′-(1,3-dimethylbutyl) -p-phenylenediamine (manufactured by Ouchi Shinsei Co., Ltd., trade name “NOCRACK 6” ") 2 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. And after cooling the obtained kneaded material to room temperature, it knead | mixed again for 2 minutes in 110 degreeC start temperature in a Brabender type mixer, Then, the kneaded material was discharged | emitted from the mixer. Next, with an open roll at 50 ° C., the obtained kneaded product was mixed with 1.40 parts of sulfur, a crosslinking accelerator: N-tert-butyl-2-benzothiazolylsulfenamide (trade name “Noxeller NS-P”, After adding 1.2 parts of Ouchi Shinsei Chemical Co., Ltd.) and 1.2 parts of diphenylguanidine (trade name “Noxeller D”, Ouchi Shinsei Chemical Co., Ltd.) and kneading them, a sheet-like rubber composition The thing was taken out.
Next, the obtained rubber composition was press-crosslinked at 160 ° C. for 20 minutes to produce a rubber cross-linked test piece. The test piece was evaluated for low heat build-up and wet grip. The results are shown in Table 1.

[Example 2]
[Production of denaturant 2]
Instead of 1-allyl-2,2 ′, 5,5′-tetramethyl- (1-aza-2,5-disilacyclopentane), N-allyl-N, N-bis (trimethylsilyl) amine 53. Except having used 3g, it carried out similarly to Example 1, and obtained the modifier 2 represented by following formula (9). The structure represented by the following formula (9) was also confirmed by ¹ H-NMR. The viscosity of the obtained modifier 2 was measured at 25 ° C. according to JIS-Z-8803 using an Ubbelohde viscometer, and found to be 300 mm ² / s.

[Production of Modified Conjugated Diene Rubber 2]
In place of 1.35 parts of the modifier 1 1.35 parts of the modifier 2 obtained above (compound represented by the above formula (9)) (1. A solid modified conjugated diene rubber 2 was obtained in the same manner as in Example 1 except that 50 mol) was used. The resulting modified conjugated diene rubber 2 had a weight average molecular weight (Mw) of 528,000 and a coupling ratio of 2 or more branches was 42.9% by weight.

[Production of rubber composition and rubber cross-linked product]
Then, in place of 100 parts of the modified conjugated diene rubber 1 and using 100 parts of the modified conjugated diene rubber 2 obtained above, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1. Obtained and evaluated in the same manner. The results are shown in Table 1.

[Comparative Example 1]
[Production of Modified Conjugated Diene Rubber 3]
Modification Example 1 Except for using 1.384 parts of Modification Agent 3 (0.384 parts per mole of n-butyllithium) as shown in the following formula (10) In the same manner as in Example 1, a solid modified conjugated diene rubber 3 was obtained. The resulting modified conjugated diene rubber 3 had a weight average molecular weight (Mw) of 316,000, and a coupling ratio of two or more branches was 1.6% by weight.

[Production of rubber composition and rubber cross-linked product]
Then, in place of 100 parts of the modified conjugated diene rubber 1 and using 100 parts of the modified conjugated diene rubber 3 obtained above, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1. Obtained and evaluated in the same manner. The results are shown in Table 1.

[Comparative Example 2]
[Production of Modified Conjugated Diene Rubber 4]
Modification Agent 1 Implemented except that 0.335 part of Modification Agent 4 represented by the following formula (11) was used instead of 1.35 parts (1.50 times the mole of n-butyllithium). In the same manner as in Example 1, a solid modified conjugated diene rubber 4 was obtained. The resulting modified conjugated diene rubber 4 had a weight average molecular weight (Mw) of 456,000, and a coupling ratio of two or more branches was 37.8% by weight.

[Production of rubber composition and rubber cross-linked product]
Then, in place of 100 parts of the modified conjugated diene rubber 1 and using 100 parts of the modified conjugated diene rubber 4 obtained above, the rubber composition and the rubber cross-linked product were obtained in the same manner as in Example 1. Obtained and evaluated in the same manner. The results are shown in Table 1.

From Table 1, when synthesizing the modified conjugated diene rubber, when the compound represented by the general formula (1) is used as a modifier, the modified conjugated diene rubber is obtained. The rubber cross-linked products were all excellent in wet grip properties and low heat build-up (Examples 1 and 2).
On the other hand, when a modified conjugated diene rubber is synthesized, even when a compound having a cyclic main chain structure composed of a repeating unit represented by —Si—O— is used as a modifier, a protected amino group-containing organic group In the case of using a material that does not have, the resulting rubber cross-linked product was inferior in wet grip and low heat build-up (Comparative Example 1).
In addition, when synthesizing a modified conjugated diene rubber, it has a protective amino group-containing organic group as a modifier, but does not have a cyclic main chain structure composed of a repeating unit represented by -Si-O- Even when the rubber was used, the resulting rubber cross-linked product was inferior in wet grip and low heat build-up (Comparative Example 2).

Claims

A first step of polymerizing a monomer comprising at least a conjugated diene compound using an organic active metal compound as a polymerization initiator in an inert solvent to obtain a conjugated diene polymer having an active end;
A second step of reacting a compound represented by the following general formula (1) with the active end of the conjugated diene polymer having the active end, and a method for producing a modified conjugated diene rubber.

(In the general formula (1), R 1 and R 3 are each independently a monovalent hydrocarbon group, a hydrogen atom or a hydroxyl group, and R 2 is an arbitrary organic group, a hydrogen atom or a hydroxyl group, X 1 is a protected amino group-containing organic group containing a primary amino group protected by a protecting group, m is an integer of 1 to 30, n is an integer of 0 to 29, and m + n is 3 to 30 is there.)
The method for producing a modified conjugated diene rubber according to claim 1, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (2).

(In the general formula (2), R 1 , R 4 to R 6 are each independently a monovalent hydrocarbon group, a hydrogen atom or a hydroxyl group, and X 1 is a primary group protected by a protecting group. A protected amino group-containing organic group containing an amino group, X 2 is an alkoxy group-containing organic group or an epoxy group-containing organic group, m is an integer of 1 to 29, p is an integer of 1 to 29, and q is 0 (It is an integer of ~ 28, and m + p + q is 3 to 30.)
In the compound represented by the general formula (2), the content ratio of the protected amino group-containing organic group to the alkoxy group-containing organic group and / or the epoxy group-containing organic group is expressed as “protected amino group-containing organic group / ( 3. The process for producing a modified conjugated diene rubber according to claim 2, wherein the molar ratio of the “alkoxy group-containing organic group and / or epoxy group-containing organic group” is 0.1 to 10.
The compound represented by the general formula (1) contains a group represented by the following general formula (3), the following general formula (4), or the following general formula (5) as the protected amino group-containing organic group. The method for producing a modified conjugated diene rubber according to any one of claims 1 to 3.

(In the general formula (3), R 7 to R 10 are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and e is an integer of 1 to 12) F is an integer from 1 to 12.)

(In the general formula (4), R 11 to R 16 are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and g is an integer of 1 to 12) .)

(In the general formula (5), R 17 and R 18 are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and h is an integer of 1 to 12) .)
The amount of the compound represented by the general formula (1) used is 0.01 to 30 mol with respect to 1 mol of the organic active metal as a polymerization initiator. A method for producing a modified conjugated diene rubber.
A modified conjugated diene rubber obtained by the production method according to any one of claims 1 to 5.
A rubber composition comprising 10 to 200 parts by weight of silica with respect to 100 parts by weight of a rubber component containing the modified conjugated diene rubber according to claim 6.
The rubber composition according to claim 7, further comprising a crosslinking agent.
A crosslinked rubber product obtained by crosslinking the rubber composition according to claim 8.
A tire comprising the rubber cross-linked product according to claim 9.