WO2018088484A1

WO2018088484A1 - Method for producing modified conjugated diene rubber

Info

Publication number: WO2018088484A1
Application number: PCT/JP2017/040455
Authority: WO
Inventors: 岳史杉村; 慎吾桑原; 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: JP7225802B2; JPWO2018088484A1

Abstract

Provided is a method for producing a modified conjugated diene rubber, which comprises: a first step wherein a monomer containing at least a conjugated diene compound is polymerized in an inert solvent, while using an organic active metal compound as a polymerization initiator, so that a conjugated diene polymer having an active terminal is obtained; and a second step wherein the active terminal of the conjugated diene polymer having an active terminal is reacted with a compound represented by general formula (1). This method for producing a modified conjugated diene rubber is configured such that 0.15 mol or more of the compound represented by general formula (1) is used per 1 mol of metal atoms in the organic active metal compound. (In general formula (1), each of R¹-R⁴ and R⁶-R⁹ independently represents a monovalent hydrocarbon group, a hydrogen atom or a hydroxyl group; R⁵ represents an arbitrary organic group, a hydrogen atom or a hydroxyl group; X¹ represents a protected amino group-containing organic group that contains a primary amino group protected by a protecting group; m represents an integer of 1-500; n represents an integer of 0-499; and (m + n) is 2-500.)

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 is represented by -Si-O-. A specific amount of a specific silane compound having a siloxane structure in the main chain structure and a primary amino group protected by a protective group is used as an active end of a conjugated diene polymer having an active end. It has been found that the modified conjugated diene rubber obtained by reacting can disperse a filler such as silica satisfactorily, thereby providing a rubber cross-linked product excellent in wet grip and low heat build-up, 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 terminus of the conjugated diene polymer having the active terminus, the general formula (1) A method for producing a modified conjugated diene rubber is provided in which the amount of the compound represented by the formula (1) is 0.15 mol or more relative to 1 mol of the metal atom in the organic active metal compound.

(In the general formula (1), R ¹ to R ⁴ and R ⁶ to R ⁹ are each independently a monovalent hydrocarbon group, a hydrogen atom or a hydroxyl group, and R ⁵ is any organic group, hydrogen An 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 500, n is an integer of 0 to 499, m + n is 2 to 500.)

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 to R ⁴ and R ⁷ to R ¹² are each independently a monovalent hydrocarbon group, a hydrogen atom or a hydroxyl group, and X ¹ is protected by a protecting group. A protected amino group-containing organic group containing a primary 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 499, p is an integer of 1 to 499, q is an integer of 0 to 498, and m + p + q is 2 to 500.)

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

(In the general formula (3), R ¹³ 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 e is an integer of 1 to 12) F is an integer from 1 to 12.)

(In the general formula (4), R ¹⁷ to R ²² 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 present invention, an organic alkali metal amide compound is preferably used as the polymerization initiator, and the organic alkali metal amide compound is more preferably a compound represented by the following general formula (5).

(In the above general formula (5), M ¹ represents an alkali metal atom, and R ²³ and R ²⁴ are each independently an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an amino group protecting group, or Represents a group capable of hydrolyzing to form a hydroxyl group, and R ²³ and R ²⁴ may be bonded to each other to form a ring structure together with the nitrogen atom to which they are bonded; In addition to the nitrogen atom to which is bonded, a ring structure may be formed together with a heteroatom other than the nitrogen atom to which these are bonded.

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 an active terminus with a compound represented by the general formula (1) described later,
The amount of the compound represented by the general formula (1) is 0.15 mol or more per 1 mol of the metal atom in the organic active metal compound.

<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 obtained by copolymerizing 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. These polymerization initiators may be used individually by 1 type, and may be used in combination of 2 or more type.

Organic alkali metal compounds are used as organic alkali metal amide compounds by reacting with secondary amine compounds such as dibutylamine, dihexylamine, dibenzylamine, pyrrolidine, piperidine, hexamethyleneimine, and heptamethyleneimine in advance. May be. By using an organic alkali metal amide compound as a polymerization initiator, the resulting rubber cross-linked product can be made more excellent in low heat buildup and wet grip properties.

Examples of the organic alkali metal amide compound include those obtained by reacting an organic alkali metal compound with a secondary amine compound, and among them, a compound represented by the following general formula (5) is preferably used. it can.

The alkyl group is not particularly limited, but an alkyl group having 1 to 20 carbon atoms is preferable, and an alkyl group having 1 to 10 carbon atoms is more preferable. Examples of such alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, and n-hexyl. Group, n-heptyl group, n-octyl group, n-decyl group and the like.

The cycloalkyl group is not particularly limited, but is preferably a cycloalkyl group having 3 to 20 carbon atoms, and more preferably a cycloalkyl group having 3 to 12 carbon atoms. Examples of such cycloalkyl groups include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and a cyclododecyl group.

The aryl group is not particularly limited, but an aryl group having 6 to 12 carbon atoms is preferable, and an aryl group having 6 to 10 carbon atoms is more preferable. Examples of such an aryl group include a phenyl group, a 1-naphthyl group, and a 2-naphthyl group.

The aralkyl group is not particularly limited, but an aralkyl group having 7 to 13 carbon atoms is preferable, and an aralkyl group having 7 to 9 carbon atoms is more preferable. Examples of such aralkyl groups include benzyl group and phenethyl group.

The amino-protecting group is not particularly limited, and more specifically, an amino-protecting group, more specifically, a primary amino group (ie, —NH ₂ ) or a secondary amino group (ie,> NH). Any group that acts as a protecting group may be used, and examples thereof include an alkylsilyl group. Examples of such alkylsilyl groups include trimethylsilyl group, triethylsilyl group, triphenylsilyl group, methyldiphenylsilyl group, ethylmethylphenylsilyl group, tert-butyldimethylsilyl group, and the like.

The group capable of generating a hydroxyl group by hydrolysis is not particularly limited, and may be any group that generates a hydroxyl group by hydrolysis in the presence of an acid, for example, an alkoxyalkyl group, an epoxy group, and the like. And a group containing
Examples of the alkoxyalkyl group include a methoxymethyl group, an ethoxymethyl group, an ethoxyethyl group, a propoxymethyl group, a butoxymethyl group, a butoxyethyl group, and a propoxyethyl group.
Examples of the group containing an epoxy group include a group represented by the following general formula (6).
-Z ¹ -Z ² -E ¹ (6)
In the general formula (6), Z ¹ is an alkylene group having 1 to 10 carbon atoms or an alkylarylene group, Z ² is a methylene group, a sulfur atom or an oxygen atom, and E ¹ is a glycidyl group.

R ²³ and R ²⁴ may be bonded to each other to form a ring structure together with the nitrogen atom to which they are bonded, and in this case, formed by R ²³ and R ²⁴ and the nitrogen atom to which they are bonded. Specific examples of the structure to be formed include an azetidine ring (R ²³ and R ²⁴ are propylene groups), a pyrrolidine ring (R ²³ and R ²⁴ are butylene groups), a piperidine ring (R ²³ and R ²⁴ are pentylene groups). And hexamethyleneimine ring (R ²³ and R ²⁴ are hexylene groups) and the like.
When R ²³ and R ²⁴ are bonded to each other to form a ring structure together with the nitrogen atom to which they are bonded, the ring structure is preferably a 4- to 8-membered ring structure.

In the general formula (5), M ¹ is an alkali metal atom. Examples of such an alkali metal atom include a lithium atom, a sodium atom, and a potassium atom. Among these, a viewpoint of polymerization activity. More preferred is a lithium atom.

In the first step of the production method of the present invention, when the compound represented by the general formula (5) is used as the polymerization initiator, the amine structure forming the organic alkali metal amide compound is the polymerization start of the polymer chain. It will remain attached to the end. Therefore, when the compound represented by the general formula (5) is used as a polymerization initiator, it is represented by the following general formula (7) at one end of the polymer chain forming the resulting conjugated diene rubber. A structure is introduced.

(In the general formula (7), each of R ²⁵ and R ²⁶ independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an amino group protecting group, or a hydrolyzed hydroxyl group. R ²⁵ and R ²⁶ may be bonded to each other to form a ring structure together with the nitrogen atom to which they are bonded, and in the case of forming the ring structure, In addition, a ring structure may be formed together with a hetero atom other than the nitrogen atom to which they are bonded.)

Examples of the alkyl group, cycloalkyl group, aryl group, aralkyl group, amino-protecting group, or group capable of hydrolyzing to generate a hydroxyl group that can be R ²⁵ and R ²⁶ include R ²³ and R in the above general formula (5). ^{In the} case where R ²⁵ and R ²⁶ are bonded to each other to form a ring structure together with the nitrogen atom to which they are bonded, R ²³ in the above general formula (5), it can be similar to R ^24.
In addition, the hydrogen atom which can become R ²⁵ and R ²⁶ is introduced when the protecting group of the amino group is removed.

In the first step of the production method of the present invention, when an organic alkali metal amide compound is used as a polymerization initiator, the resulting conjugated diene rubber has an amine structure at one end and the other end. And a specific modified structure derived from the compound represented by the general formula (1). As a result, due to the effect of such an amine structure, the resulting rubber cross-linked product using the conjugated diene rubber is more excellent in low heat generation and wet grip properties.

The method of adding the organic alkali metal amide compound as a polymerization initiator to the polymerization system is not particularly limited, and a secondary amine compound is reacted with the organic alkali metal compound in advance to obtain an organic alkali metal amide compound. A method of mixing this with a monomer containing a conjugated diene compound and allowing the polymerization reaction to proceed can be employed. Alternatively, an organic alkali metal amide compound is generated in the polymerization system by adding the organic alkali metal compound and the secondary amine compound separately to the polymerization system and mixing them with a monomer containing a conjugated diene compound. Thus, a method of advancing the polymerization reaction may be employed. The reaction conditions such as the reaction temperature are not particularly limited, and may be according to the intended polymerization reaction conditions, for example.

The amount of secondary amine compound used may be determined according to the amount of the desired polymerization initiator added, but is usually 0.01 to 1.5 mmol, preferably 0.1, per 1 mmol of the organic alkali metal compound. It is in the range of ~ 1.4 mmol, more preferably 0.5 to 1.3 mmol.

The amount of the polymerization initiator used may be determined according to the molecular weight of the target conjugated diene polymer chain, but is usually 1 to 50 mmol, preferably 1.5 to 20 mmol, per 1000 g of monomer. The range of 2 to 15 mmol is preferred.

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 500, preferably an integer of 1 to 250, more preferably an integer of 1 to 100. n is an integer of 0 to 499, preferably an integer of 0 to 249, more preferably an integer of 0 to 99. Further, m + n is 2 to 500, preferably 2 to 250, more preferably 2 to 100.

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”). Examples of the protected amino group-containing organic group containing a primary amino group protected by a protecting group include groups in which two hydrogen atoms of a primary amino group (that is, —NH ₂ ) act as protecting groups for amino groups. An organic group containing a protected amino group having a structure substituted with, and the protective group can be deprotected by a method using an acid or a base, or by a hydrolysis reaction. Any group providing a secondary amino group may be used, and is not particularly limited. Examples thereof include a silyl group. Such a protected amino group-containing organic group contains a primary amino group as a result of deprotection of the protective group, thereby mainly improving the affinity with a filler such as silica. It is thought that it acts on.

As such a protected amino group-containing organic group, for example, a group represented by the following general formula (3) or the following general formula (4) is preferably exemplified. 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 ¹³ 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. 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 ¹⁷ to R ²² each independently represents 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 group represented by the general formula (3), the group represented by —SiR ¹³ R ¹⁴ — (CH ₂ ) _f —SiR ¹⁵ R ¹⁶ — represents a method using an acid or a base, hydrolysis It acts as a protecting group that can be deprotected by the reaction. Similarly, in the group represented by the general formula (4), the group represented by —SiR ¹⁷ R ¹⁸ R ¹⁹ and the group represented by —SiR ²⁰ R ²¹ R ²² use an acid or a base. It acts as a protecting group that can be deprotected by a method or hydrolysis reaction.

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). A group represented by the above formula (4) is preferred, and a group represented by the above formula (4) is more preferred.

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, bis (di-t-butylmethylsilyl) amino group, bis (di-t -Butylisobutylsilyl) amino group, 2,2,5,5-tetramethyl-1,2,5-azadisilolidine group and the like.

In the general formula (1), R ¹ to R ⁴ and R ⁶ to R ⁹ 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 ⁵ 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 ⁵ there are a plurality, the plurality of R ⁵ may be different be 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), m is an integer of 1 to 499, preferably an integer of 1 to 249, more preferably an integer of 1 to 99. p is an integer of 1 to 499, preferably an integer of 1 to 249, more preferably an integer of 1 to 99, and q is an integer of 0 to 498, preferably an integer of 0 to 248, more preferably It is an integer of 0 to 98, more preferably q is 0. M + p + q is 2 to 500, preferably 2 to 250, more preferably 2 to 100.

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, Alkoxysilyl groups, etc. are mentioned, but the modification effect of conjugated diene rubber, specifically, the affinity for silica and other fillers is improved, and when silica and other fillers are blended, the filling of silica and the like A compound containing an alkoxysilyl group is preferred from the viewpoint that the effect of enhancing the dispersibility of the agent is high, and that the resulting rubber cross-linked product can be made more excellent in low heat build-up and wet grip properties.

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 (8) may be mentioned.

In the general formula (8), each R ²⁷ independently represents an alkyl group having 1 to 20 carbon atoms, preferably an alkyl group having 1 to 10 carbon atoms, and R ²⁸ 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 1 to 10, and k is an integer of 1 to 3. Incidentally, when k is 2 or 3, R ²⁷ is a presence of a plurality, the plurality of R ²⁷ may be different be the same as each other. Similarly, when k is 1, R ²⁸ is a presence of a plurality, the plurality of R ²⁸ 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; monoalkoxydialkylsilyl groups such as methoxydimethylsilyl group, ethoxydimethylsilyl group, methoxydiethylsilyl group, ethoxydiethylsilyl group; and the like. Among these, the modification effect of the conjugated diene rubber, specifically, the affinity for the filler such as silica is improved, and the dispersibility of the filler such as silica when the filler such as silica is blended. From the viewpoint that the resulting rubber cross-linked product can be made more excellent in low heat build-up and wet grip properties, a trialkoxysilyl group is preferred, and a trimethoxysilyl group is more preferred. .

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 to R ⁴ and R ⁷ to R ¹² 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 1/30 to 30/1, more preferably 1/20 to 20/1, It is preferably 1/10 to 10/1. 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 = 7 and m + n = 14 and a compound with m = 8 and m + n = 16 may be used, or m = 7 and m + n = 14. A mixture of two or more compounds having different X ¹ may be used. Furthermore, m = 7, m + n = 14, and two or more compounds having different X ¹ and m = 8, m + n = 16, and 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 metal in the organic active metal compound used as a polymerization initiator in the 1st process mentioned above. It is 0.15 mol or more, preferably 0.15 to 20 mol, more preferably 0.15 to 15 mol, more preferably 0.15 to 10 mol, per mol of atom. More preferably, the ratio is as follows. If the amount of the compound represented by the general formula (1) is too small, the modification effect by the compound represented by the general formula (1) becomes insufficient, and the wet grip property when the rubber cross-linked product is obtained. The improvement effect of low exothermic property is insufficient. On the other hand, if it is too much, side reactions and impurities due to the compound represented by the general formula (1) are generated, and as a result, the wet grip property and the low heat build-up property in the case of a rubber cross-linked product may be deteriorated. .

In the present invention, as a modifier used when producing a modified conjugated diene rubber, as shown in the general formula (1), it has a main chain structure composed of a siloxane structure represented by —Si—O—. In addition, a specific amount of a compound in which a protected amino group-containing organic group is introduced into such a main chain structure is used. Therefore, a main chain structure composed of a siloxane structure represented by —Si—O— is used. Compared with the case where it does not have, the function by the protected amino group-containing organic group including the primary amino group protected by the protecting group described above can be sufficiently exhibited. 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. At this time, as described above, the compound is protected by a protective group derived from the compound represented by the general formula (1) introduced into the modified conjugated diene rubber after the modification reaction by steam stripping. It is considered that the primary amino group is formed by the deprotection of the protective group in the protected amino group-containing organic group containing the primary amino group by hydrolysis.

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 reacting a specific amount of the compound represented by the general formula (1) as a modifier. As described above, the affinity for the filler such as silica is high, and the filler such as silica can be favorably dispersed. 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 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-8320” 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-8320” manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Column temperature: 40 ° C

[Microstructure of Modified Conjugated Diene Rubber]
^It was measured by ¹ H-NMR.
Measuring instrument: (JEOL, product name “JNM-ECA-400WB”
Measuring solvent: deuterated chloroform

[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 38.0 g of methyl hydrogen polysiloxane represented by the following formula (9), and heated to 40 ° C. with stirring under a nitrogen stream.

Next, 0.9 g of a toluene solution of platinum-1,3-divinyl-1,3-dimethyldisiloxane complex (Pt concentration 0.17 wt%) was added, and N-allyl-N, N-bis (trimethylsilyl) amine 79 was added. 0.7 g was added dropwise so as to keep the reaction temperature at 40 to 80 ° C. After completion of the dropping, stirring was continued at 80 ° C. for 1.5 hours, and then 0.5 g of the reaction solution was collected, and an alkali decomposition gas generation method (remaining Si—H group was decomposed with KOH ethanol / water solution to generate hydrogen The reaction rate was confirmed to be about 70% by calculating the reaction rate from the gas volume). Next, 45.0 g of 5-hexenyltrimethoxysilane was added dropwise so as to keep the reaction temperature at 80 to 90 ° C. After completion of the dropping, 0.9 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 90-100 ° C. for 12 hours. 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 150 ° C. under reduced pressure to distill off the low-boiling components for 3.5 hours, and 138.6 g of the modifier 1 represented by the following formula (10) was obtained. The structure represented by the following formula (10) was also confirmed by ¹ H-NMR. With respect to the obtained modifier 1, the viscosity was measured according to JIS-Z-8803 at 25 ° C. using an Ubbelohde viscosity tube, and it was 1040 mm ² / s.

[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 0.042 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 was in the range of 95% to 100%, the modifier 1 obtained above (compound represented by the above formula (10)) After adding 0.589 parts (0.3 times mole with respect to the amount of n-butyllithium used) and reacting for 30 minutes, 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 410,000. The modified conjugated diene rubber 1 had a styrene unit content of 21.2% by weight and a vinyl bond content in the butadiene unit of 62.8 mol%.

[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, and then 53 parts of silica (trade name “Zeosil 1165MP”, manufactured by Rhodia), process oil ( 30 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 at 110 ° C. as the starting temperature, followed by 27 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 Chemical Co., Ltd., trade name “NOKU” Tsu added click 6C ") 2 parts, was further kneaded for 2.5 minutes, discharging a kneaded product 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 1.5 parts of sulfur and a crosslinking accelerator: N-cyclohexyl-2-benzothiazolylsulfenamide (trade name “Noxeller CZ-G”, Ouchi After adding 1.8 parts of Shinsei Chemical Co., Ltd.) and 1.5 parts of crosslinking accelerator: 1,3-diphenylguanidine (trade name “Noxeller D”, produced by Ouchi Shinsei Chemical Co., Ltd.) and kneading them. Then, the sheet-like rubber composition 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 Modified Conjugated Diene Rubber 2, Rubber Composition, and Rubber Cross-Linked Product]
Except that the amount of modifier 1 used was changed from 0.589 parts to 1.473 parts (0.75 times the amount of n-butyllithium used), the same operation as in Example 1 was carried out. A solid modified conjugated diene rubber 2 was obtained. The resulting modified conjugated diene rubber 2 had a weight average molecular weight (Mw) of 432,000.
Then, instead of the modified conjugated diene rubber 1, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the obtained modified conjugated diene rubber 2 was used. went. The results are shown in Table 1.

Example 3
[Production of Modified Conjugated Diene Rubber 3, Rubber Composition and Crosslinked Rubber]
Except that the amount of modifier 1 used was changed from 0.589 parts to 1.963 parts (1.00 times the amount of n-butyllithium used), the same operation as in Example 1 was carried out. A solid modified conjugated diene rubber 3 was obtained. The resulting modified conjugated diene rubber 3 had a weight average molecular weight (Mw) of 444,000.
Then, in place of the modified conjugated diene rubber 1, the rubber composition and the crosslinked rubber were obtained in the same manner as in Example 1 except that the obtained modified conjugated diene rubber 3 was used. went. The results are shown in Table 1.

Example 4
[Production of denaturant 2]
In the same manner as in Example 1 except that the amount of N-allyl-N, N-bis (trimethylsilyl) amine and 5-hexenyltrimethoxysilane used was changed to a molar ratio of 6: 1, the following formula The modifier 2 represented by (11) was obtained. The structure represented by the following formula (11) was also confirmed by ¹ H-NMR. The viscosity of the obtained modifier 2 was 1940 mm ² / s as measured according to JIS-Z-8803 using an Ubbelohde viscosity tube at 25 ° C.

[Production of Modified Conjugated Diene Rubber 4, Rubber Composition and Crosslinked Rubber]
Instead of the modifier 1, 2.556 parts of the modifier 2 obtained above (compound represented by the above formula (11)) (1.00 mol per mol of n-butyllithium) The solid modified conjugated diene rubber 4 was obtained in the same manner as in Example 1 except that was used. The resulting modified conjugated diene rubber 4 had a weight average molecular weight (Mw) of 395,000.
Then, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the obtained modified conjugated diene rubber 4 was used in place of the modified conjugated diene rubber 1, and evaluation was performed in the same manner. went. The results are shown in Table 1.

Example 5
[Production of denaturant 3]
Instead of methylhydrogenpolysiloxane represented by the above formula (9), 44.0 g of methylhydrogenpolysiloxane represented by the following formula (12) was used, and N-allyl-N, N-bis ( Example 3 except that the amount of trimethylsilyl) amine used was 75.4 g, the amount of 5-hexenyltrimethoxysilane used was 25.5 g, and these ratios were changed to a molar ratio of 3: 1. Thus, a modifier 3 represented by the following formula (13) was obtained. The structure represented by the following formula (13) was also confirmed by ¹ H-NMR. The viscosity of the obtained modifier 3 was 230 mm ² / s when measured according to JIS-Z-8803 using an Ubbelohde viscosity tube at 25 ° C.

[Production of Modified Conjugated Diene Rubber 5, Rubber Composition and Crosslinked Rubber]
Instead of the modifier 1, 1.809 parts of the modifier 3 obtained above (compound represented by the above formula (13)) (1.00 mol per mol of n-butyllithium) The solid modified conjugated diene rubber 5 was obtained in the same manner as in Example 1 except that was used. The resulting modified conjugated diene rubber 5 had a weight average molecular weight (Mw) of 420,000.
Then, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the obtained modified conjugated diene rubber 5 was used instead of the modified conjugated diene rubber 1, and evaluation was performed in the same manner. went. The results are shown in Table 1.

Example 6
[Production of denaturant 4]
In the same manner as in Example 1 except that the amount of N-allyl-N, N-bis (trimethylsilyl) amine and 5-hexenyltrimethoxysilane used was changed to a molar ratio of 1: 4, the following formula The modifier 4 represented by (14) was obtained. The structure represented by the following formula (14) was also confirmed by ¹ H-NMR. The viscosity of the obtained modifier 4 was 250 mm ² / s as measured according to JIS-Z-8803 using an Ubbelohde type viscosity tube at 25 ° C.

[Production of Modified Conjugated Diene Rubber 6, Rubber Composition, and Rubber Cross-Linked Product]
Instead of the modifier 1, 2.574 parts of the modifier 4 obtained above (compound represented by the above formula (14)) (1.00 mol per mol of the amount of n-butyllithium used) The solid modified conjugated diene rubber 6 was obtained in the same manner as in Example 1 except that was used. The resulting modified conjugated diene rubber 6 had a weight average molecular weight (Mw) of 611,000.
Then, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the obtained modified conjugated diene rubber 6 was used in place of the modified conjugated diene rubber 1, and evaluation was similarly performed. went. The results are shown in Table 1.

Example 7
[Production of denaturant 5]
Instead of 5-hexenyltrimethoxysilane, 45.3 g of allyl glycidyl ether was used, and the amount of N-allyl-N, N-bis (trimethylsilyl) amine used was changed to N-allyl-N, N-bis (trimethylsilyl). A modifier 5 represented by the following formula (15) was obtained in the same manner as in Example 1 except that the molar ratio of amine to allyl glycidyl ether was changed to 1: 1. The structure represented by the following formula (15) was also confirmed by ¹ H-NMR. The viscosity of the obtained modifier 5 was measured according to JIS-Z-8803 using an Ubbelohde type viscosity tube at 25 ° C. and found to be 890 mm ² / s.

[Production of Modified Conjugated Diene Rubber 7, Rubber Composition and Crosslinked Rubber]
Instead of the modifier 1, the modifier 5 obtained above (compound represented by the above formula (15)) 1.665 parts (1.00 mol per mol of n-butyllithium) The solid modified conjugated diene rubber 7 was obtained in the same manner as in Example 1 except that was used. The resulting modified conjugated diene rubber 7 had a weight average molecular weight (Mw) of 552,000.
Then, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the obtained modified conjugated diene rubber 7 was used instead of the modified conjugated diene rubber 1, and evaluation was performed in the same manner. went. The results are shown in Table 1.

Example 8
[Production of Modified Conjugated Diene Rubber 8, Rubber Composition and Crosslinked Rubber]
Except that the amount of modifier 5 used was changed from 1.665 parts to 2.498 parts (1.50 mol per mole of n-butyllithium), the same operation as in Example 7 was carried out. A solid modified conjugated diene rubber 8 was obtained. The resulting modified conjugated diene rubber 8 had a weight average molecular weight (Mw) of 536,000.
Then, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the obtained modified conjugated diene rubber 8 was used in place of the modified conjugated diene rubber 1, and evaluation was performed in the same manner. went. The results are shown in Table 1.

Example 9
[Production of denaturant 6]
Synthesis was carried out in the same manner as in Example 1 except that 5-hexenyltrimethoxysilane was not used and the amount of N-allyl-N, N-bis (trimethylsilyl) amine used was 117.1 g. The modifier 6 represented by this was obtained. The structure represented by the following formula (16) was also confirmed by ¹ H-NMR. The viscosity of the obtained modifier 6 was measured according to JIS-Z-8803 using an Ubbelohde viscosity tube at 25 ° C., and it was 4410 mm ² / s.

[Production of Modified Conjugated Diene Rubber 9, Rubber Composition, and Rubber Cross-Linked Product]
Instead of the modifier 1, 2.547 parts of the modifier 6 obtained above (compound represented by the above formula (16)) (1.00 mol per mol of n-butyllithium) The solid modified conjugated diene rubber 9 was obtained in the same manner as in Example 1 except that was used. The resulting modified conjugated diene rubber 9 had a weight average molecular weight (Mw) of 292,000.
Then, instead of the modified conjugated diene rubber 1, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the obtained modified conjugated diene rubber 9 was used. went. The results are shown in Table 1.

Example 10
[Production of Modified Conjugated Diene Rubber 10]
In a nitrogen atmosphere, an autoclave was charged with 800 parts of cyclohexane, 94.8 parts of 1,3-butadiene, 25.2 parts of styrene, 0.187 parts of tetramethylethylenediamine and 0.059 parts of piperidine, and then n-butyllithium. 0.042 part 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%, the modifier 1 (compound represented by the above formula (10)) obtained in Example 1 was used. ) 1.963 parts (1.00 mol per mol of n-butyllithium) were added and reacted for 30 minutes, then 0.064 parts of methanol was added as a polymerization terminator, and conjugated diene was added. A solution containing a 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 10. The resulting modified conjugated diene rubber 10 had a weight average molecular weight (Mw) of 390,000.

[Production of rubber composition and rubber cross-linked product]
Then, in place of the modified conjugated diene rubber 1, the rubber composition and the crosslinked rubber were obtained in the same manner as in Example 1 except that the modified conjugated diene rubber 10 obtained above was used. Was evaluated. The results are shown in Table 2.

Example 11
[Production of Modified Conjugated Diene Rubber 11, Rubber Composition and Crosslinked Rubber]
A solid modified conjugated diene rubber 11 was obtained in the same manner as in Example 10 except that 0.071 part of azepan was used instead of piperidine. The resulting modified conjugated diene rubber 11 had a weight average molecular weight (Mw) of 359,000.
Then, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the obtained modified conjugated diene rubber 11 was used in place of the modified conjugated diene rubber 1, and evaluation was similarly performed. went. The results are shown in Table 2.

Example 12
[Production of Modified Conjugated Diene Rubber 12, Rubber Composition, and Rubber Cross-Linked Product]
A solid modified conjugated diene rubber 12 was obtained in the same manner as in Example 10 except that 0.153 part of dihexylamine was used instead of piperidine. The resulting modified conjugated diene rubber 12 had a weight average molecular weight (Mw) of 421,000.
Then, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the obtained modified conjugated diene rubber 12 was used instead of the modified conjugated diene rubber 1, and evaluation was performed in the same manner. went. The results are shown in Table 2.

Example 13
[Production of Modified Conjugated Diene Rubber 13, Rubber Composition and Crosslinked Rubber]
In place of piperidine, 0.153 parts of dihexylamine was used, and in place of the modifier 1, the modifier 5 obtained in Example 7 (compound represented by the above formula (15)) 2.498 parts ( A solid modified conjugated diene rubber 13 was obtained in the same manner as in Example 10 except that 1.50 times mol) was used relative to the amount of n-butyllithium used. The resulting modified conjugated diene rubber 13 had a weight average molecular weight (Mw) of 509,000.
Then, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the obtained modified conjugated diene rubber 13 was used in place of the modified conjugated diene rubber 1, and evaluation was similarly performed. went. The results are shown in Table 2.

[Comparative Example 1]
[Production of Modified Conjugated Diene Rubber 14]
Example 1 and Example 1 were used except that 0.207 parts of the modifying agent 7 represented by the following formula (17) (0.20 times mol with respect to the amount of n-butyllithium) used was used instead of the modifying agent 1. By operating in the same manner, a solid modified conjugated diene rubber 14 was obtained. The resulting modified conjugated diene rubber 14 had a weight average molecular weight (Mw) of 455,000.

[Production of rubber composition and rubber cross-linked product]
Then, in place of the modified conjugated diene rubber 1, the rubber composition and the rubber cross-linked product were obtained in the same manner as in Example 1 except that the modified conjugated diene rubber 14 obtained above was used. Was evaluated. The results are shown in Table 3.

[Comparative Example 2]
[Manufacture of Modified Conjugated Diene Rubber 15, Manufacturing of Rubber Composition and Crosslinked Rubber]
Except that the amount of modifier 1 used was changed from 0.589 parts to 0.137 parts (0.07 moles relative to the amount of n-butyllithium), the same operation as in Example 1 was carried out. A solid modified conjugated diene rubber 15 was obtained. The resulting modified conjugated diene rubber 15 had a weight average molecular weight (Mw) of 355,000.
Then, in place of the modified conjugated diene rubber 1, the rubber composition and the crosslinked rubber were obtained in the same manner as in Example 1 except that the obtained modified conjugated diene rubber 15 was used. went. The results are shown in Table 3.

[Comparative Example 3]
[Production of Modified Conjugated Diene Rubber 16, Production of Rubber Composition and Crosslinked Rubber]
Except that the amount of modifier 1 used was changed from 0.589 parts to 0.275 parts (0.14 moles relative to the amount of n-butyllithium), the same operation as in Example 1 was carried out. A solid modified conjugated diene rubber 16 was obtained. The resulting modified conjugated diene rubber 16 had a weight average molecular weight (Mw) of 383,000.
Then, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the obtained modified conjugated diene rubber 16 was used in place of the modified conjugated diene rubber 1, and evaluation was performed in the same manner. went. The results are shown in Table 3.

[Comparative Example 4]
[Production of Modified Conjugated Diene Rubber 17, Rubber Composition, and Rubber Cross-Linked Product]
Example 1 and Example 1 were used except that 5.310 parts of a modifier 8 represented by the following formula (18) (1.00 moles relative to the amount of n-butyllithium) used was used instead of the modifier 1. By operating in the same manner, a solid modified conjugated diene rubber 17 was obtained. The resulting modified conjugated diene rubber 17 had a weight average molecular weight (Mw) of 383,000.
Then, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the obtained modified conjugated diene rubber 17 was used in place of the modified conjugated diene rubber 1, and evaluation was performed in the same manner. went. The results are shown in Table 3.

[Comparative Example 5]
[Production of denaturant 9]
Instead of methylhydrogenpolysiloxane represented by the above formula (9), 75.2 g of methylhydrogensiloxane represented by the following formula (19) is used, and N is used without using 5-hexenyltrimethoxysilane. A modifier 9 represented by the following formula (20) was obtained in the same manner as in Example 1 except that the amount of allyl-N, N-bis (trimethylsilyl) amine used was changed to 74.9 g. The structure represented by the following formula (20) was also confirmed by ¹ H-NMR. The viscosity of the obtained modifier 9 was measured according to JIS-Z-8803 using an Ubbelohde type viscosity tube at 25 ° C. and found to be 6 mm ² / s.

[Production of Modified Conjugated Diene Rubber 18, Rubber Composition and Crosslinked Rubber]
Instead of the modifier 1, 0.284 parts of the modifier 9 obtained above (compound represented by the above formula (20)) (1.00 mol per mol of n-butyllithium) The solid modified conjugated diene rubber 18 was obtained in the same manner as in Example 1 except that was used. The resulting modified conjugated diene rubber 18 had a weight average molecular weight (Mw) of 229,000.
Then, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the obtained modified conjugated diene rubber 18 was used in place of the modified conjugated diene rubber 1, and evaluation was similarly performed. went. The results are shown in Table 3.

[Comparative Example 6]
[Production of Modified Conjugated Diene Rubber 19, Rubber Composition and Crosslinked Rubber]
Example 1 was used except that 0.315 parts of the modifying agent 10 represented by the following formula (21) (1.00 times the amount of n-butyllithium used) was used in place of the modifying agent 1. In the same manner as described above, a solid modified conjugated diene rubber 19 was obtained. The resulting modified conjugated diene rubber 19 had a weight average molecular weight (Mw) of 383,000.
Then, a rubber composition and a rubber cross-linked product were obtained in the same manner as in Example 1 except that the obtained modified conjugated diene rubber 19 was used in place of the modified conjugated diene rubber 1, and evaluation was performed in the same manner. went. The results are shown in Table 3.

From Table 1, Table 2, and Table 3, when a modified conjugated diene rubber is synthesized, when a specific amount of the compound represented by the above general formula (1) is used as a modifier, a crosslinked rubber product is obtained. Were excellent in wet grip and low heat build-up (Examples 1 to 13).
On the other hand, when synthesizing a modified conjugated diene rubber, if the modifier does not have a protected amino group-containing organic group, the resulting rubber cross-linked product is inferior in wet grip and low heat build-up. (Comparative Examples 1 and 4).
Further, when the modified conjugated diene rubber is synthesized, even when the compound represented by the above general formula (1) is used as a modifier, if the amount used is too small, the resulting rubber cross-linked product is a wet grip. The improvement effect of heat resistance and low exothermic property was not obtained (Comparative Examples 2 and 3).
Furthermore, when synthesizing a modified conjugated diene rubber, a modifier having a protected amino group-containing organic group but not corresponding to the compound represented by the above general formula (1) is also obtained. The resulting rubber cross-linked product was inferior in wet grip and low heat build-up (Comparative Examples 5 and 6).

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 the active terminus of the conjugated diene polymer having the active terminus with a compound represented by the following general formula (1),
A method for producing a modified conjugated diene rubber, wherein the amount of the compound represented by the general formula (1) is 0.15 mol or more relative to 1 mol of a metal atom in the organic active metal compound.

(In the general formula (1), R 1 to R 4 and R 6 to R 9 are each independently a monovalent hydrocarbon group, a hydrogen atom or a hydroxyl group, and R 5 is any organic group, hydrogen An 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 500, n is an integer of 0 to 499, m + n is 2 to 500.)
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 to R 4 and R 7 to R 12 are each independently a monovalent hydrocarbon group, a hydrogen atom or a hydroxyl group, and X 1 is protected by a protecting group. A protected amino group-containing organic group containing a primary 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 499, p is an integer of 1 to 499, q is an integer of 0 to 498, and m + p + q is 2 to 500.)
The compound represented by the general formula (1) contains a group represented by the following general formula (3) or the following general formula (4) as the protected amino group-containing organic group. A method for producing the modified conjugated diene rubber.

(In the general formula (3), R 13 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 e is an integer of 1 to 12) F is an integer from 1 to 12.)

(In the general formula (4), R 17 to R 22 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) .)
The method for producing a conjugated diene rubber according to any one of claims 1 to 3, wherein an organic alkali metal amide compound is used as the polymerization initiator.
The method for producing a conjugated diene rubber according to claim 4, wherein the organic alkali metal amide compound is a compound represented by the following general formula (5).

(In the above general formula (5), M 1 represents an alkali metal atom, and R 23 and R 24 are each independently an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an amino group protecting group, or Represents a group capable of hydrolyzing to form a hydroxyl group, and R 23 and R 24 may be bonded to each other to form a ring structure together with the nitrogen atom to which they are bonded; In addition to the nitrogen atom to which is bonded, a ring structure may be formed together with a heteroatom other than the nitrogen atom to which these are bonded.
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.