WO2018199280A1 - Crosslinked rubber and tire - Google Patents

Abstract

A crosslinked rubber obtained by crosslinking a rubber composition, wherein the rubber composition contains: (A) a conjugated diene polymer having a weight-average molecular weight of 1.0 x 10⁵ to 2.0 x 10⁶ in terms of polystyrene by gel permeation chromatography, the hydrogenation rate of structural units derived from butadiene being 60-90%; (B) a hydrogenated or un-hydrogenated conjugated diene polymer having structural units derived from butadiene and having a different hydrogenation rate than does component (A); (C) silica; and (D) a crosslinking agent, the co-vulcanization parameter represented by numerical formula (1) in the rubber composition being 0.85 or higher. (1): Co-vulcanization parameter = X/(Y × α + Z × β)

Description

Cross-linked rubber and tire Cross-reference of related applications

This application is based on Japanese Patent Application No. 2017-90717 filed on April 28, 2017, the contents of which are incorporated herein by reference.

This disclosure relates to crosslinked rubber and tires.

A conjugated diene polymer obtained by polymerization using a conjugated diene compound has good properties such as heat resistance, wear resistance, mechanical strength, and moldability, so that a pneumatic tire, a vibration-proof rubber, Widely used in various industrial products such as hoses.

For example, rubber compositions used for manufacturing treads and sidewalls of pneumatic tires include reinforcing agents such as carbon black and silica together with conjugated diene polymers in order to improve tire durability and wear resistance. It is known to contain. Among these, silica is effective in that it can improve durability and wear resistance while achieving both wet grip performance and low rolling resistance of the tire, and has been actively used in recent years.

As a polymer component of a rubber composition for tires, it has been proposed to use a hydrogenated conjugated diene polymer in which the butadiene portion of a conjugated diene polymer is hydrogenated (see, for example, Patent Documents 1 to 5). . Patent Document 1 discloses a rubber composition containing a styrene-butadiene copolymer having a specific microstructure and a hydrogenated styrene-butadiene copolymer having a specific microstructure in a specific blending ratio. . Patent Document 2 discloses a rubber composition containing a hydrogenated conjugated diene polymer, silica, an organic silane coupling agent, and a vulcanizing agent.

Patent Document 3 discloses (A) a halogenated butyl rubber or a halogenated product of a copolymer of isobutylene and p-methylstyrene, (B) a styrene-butadiene copolymer having a specific microstructure, and (C) a specific microscopic structure. A rubber composition comprising a hydrogenated low molecular weight styrene-butadiene copolymer having a structure, (D) silica, (E) a softening agent, and (F) a silane coupling agent is described. Patent Document 4 discloses a hydrogenated conjugated diene polymer modified with a compound having an ester group and / or a carboxyl group, a hydrogenated conjugated diene polymer modified with a compound having a nitrogen-containing heterocyclic group, and silica. A rubber composition containing

Patent Document 5 discloses a tire member having high strength and low wear using a hydrogenated product of a modified conjugated diene polymer having a functional group such as an amino group or an alkoxysilyl group at one or both ends. It is disclosed. The example of Patent Document 5 discloses an example in which a modified hydrogenated conjugated diene polymer having a hydrogenation rate of 60% or more is blended with a rubber composition, and Comparative Example 1 in which hydrogenation is not performed is disclosed. It has been revealed that the strength and wear resistance of the vulcanized rubber are improved as compared with the above.

JP 2000-129037 A International Publication No. 1996/005250 JP 2005-290139 A JP 2013-144743 A International Publication No. 2014/133097

Since a conjugated diene polymer having a high hydrogenation rate is expensive, it may be impeded from practical use in terms of cost in producing a rubber product having excellent strength. Therefore, it is necessary to develop a material capable of obtaining a rubber product having excellent strength while suppressing raw material costs.

The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide a crosslinked rubber that has high strength and can be manufactured at a low price.

According to the present disclosure, the following crosslinked rubber and tire are provided.

（Ｂ）ブタジエン由来の構造単位を有し、かつ、水添率が前記（Ａ）成分とは異なる水添又は未水添の共役ジエン系重合体、
（Ｃ）シリカ、及び、
（Ｄ）架橋剤、を含有し、前記ゴム組成物における下記数式（１）で表される共加硫パラメータが０．８５以上である、架橋ゴム。
　共加硫パラメータ＝Ｘ／（Ｙ×α＋Ｚ×β）　　　…（１）
（数式（１）中、αは、前記ゴム組成物中の前記（Ａ）成分と前記（Ｂ）成分との合計量に対する前記（Ａ）成分の含有割合であり、βは、前記ゴム組成物中の前記（Ａ）成分と前記（Ｂ）成分との合計量に対する前記（Ｂ）成分の含有割合であり、α＋β＝１の関係を満たす。Ｘは、前記ゴム組成物を試料として用いて、架橋温度で、振幅角±１°、ねじり振動数１００ｃｐｍの条件で振動式加硫試験機により測定される測定３０分での最大トルクから最小トルクを差し引いたトルク差であり、Ｙは、前記ゴム組成物中の前記（Ｂ）成分を前記（Ａ）成分に置き換えたものを試料として用いたときの前記トルク差であり、Ｚは、前記ゴム組成物中の前記（Ａ）成分を前記（Ｂ）成分に置き換えたものを試料として用いたときの前記トルク差である。）
　［２］上記［１］の架橋ゴムによって、少なくともトレッド又はサイドウォールが形成されたタイヤ。 [1] A crosslinked rubber obtained by crosslinking a rubber composition, wherein the rubber composition has the following (A) to (D):
(A) The polystyrene-reduced weight average molecular weight by gel permeation chromatography is 1.0 × 10 ⁵ to 2.0 × 10 ⁶ , has a structural unit derived from butadiene, and is represented by the following formula (2). The structural ratios of the structural unit represented by the structural unit represented by the following formula (3), the structural unit represented by the following formula (4), and the structural unit represented by the following formula (5) are p, q, a hydrogenated conjugated diene polymer satisfying the following mathematical formula (6) when r and s:
0.60 ≦ (p + r) / (p + q + r + s) ≦ 0.90 (6)

(B) a hydrogenated or unhydrogenated conjugated diene polymer having a structural unit derived from butadiene and having a hydrogenation rate different from that of the component (A),
(C) silica and
(D) A crosslinked rubber containing a crosslinking agent and having a co-vulcanization parameter represented by the following formula (1) in the rubber composition of 0.85 or more.
Co-vulcanization parameter = X / (Y × α + Z × β) (1)
(In Formula (1), α is the content ratio of the component (A) to the total amount of the component (A) and the component (B) in the rubber composition, and β is the rubber composition. It is the content ratio of the component (B) with respect to the total amount of the component (A) and the component (B), and satisfies the relationship of α + β = 1, where X is the rubber composition as a sample, This is the torque difference obtained by subtracting the minimum torque from the maximum torque measured in 30 minutes using a vibration type vulcanization tester under the conditions of a crosslinking temperature, an amplitude angle of ± 1 °, and a torsional frequency of 100 cpm. Y is the rubber It is the torque difference when the component (B) in the composition is replaced with the component (A) as a sample, and Z is the component (A) in the rubber composition (B ) The torque difference when the sample is replaced with a component. .)
[2] A tire in which at least a tread or a sidewall is formed by the crosslinked rubber of [1].

According to the rubber composition, in a rubber composition containing at least a hydrogenated product as a conjugated diene polymer, when a part of the conjugated diene polymer in the rubber composition is a polymer having a low hydrogenation rate. In addition, a high-strength crosslinked rubber having excellent tensile strength and elongation at break can be obtained. Therefore, a high-strength rubber product can be manufactured at a low price.

The crosslinked rubber of the present disclosure includes the following (A) to (D):
(A) The weight average molecular weight in terms of polystyrene by gel permeation chromatography is 1.0 × 10 ⁵ to 2.0 × 10 ⁶ , and the hydrogenation rate of the structural unit derived from butadiene is 60 to 90%. Conjugated diene polymers,
(B) Conjugated diene polymer (excluding those corresponding to component (A)),
(C) silica, and (D) a crosslinking agent,
Is a crosslinked rubber obtained by crosslinking a rubber composition having a co-vulcanization parameter represented by the above formula (1) of 0.85 or more. Hereafter, each component contained in the rubber composition used for manufacture of the crosslinked rubber of this indication is explained in full detail.

<(A) component>
The (A) component conjugated diene polymer (hereinafter also referred to as “polymer (A)”) is a hydrogenated product obtained by hydrogenating a polymer having a structural unit derived from a conjugated diene compound. The polymer (A) can be produced by a method including the following polymerization step and hydrogenation step.

(Polymerization process)
In this step, a monomer containing a conjugated diene compound is polymerized to obtain a conjugated diene polymer having an active end. The conjugated diene compound used for the polymerization may be 1,3-butadiene alone, or a conjugated diene compound other than 1,3-butadiene (hereinafter also referred to as “other conjugated diene compound”) may be used in combination. Examples of other conjugated diene compounds include isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 1,3-heptadiene, and 2-phenyl-1,3-butadiene. , 3-methyl-1,3-pentadiene, 2-chloro-1,3-butadiene and the like. Of these, isoprene and 2,3-dimethyl-1,3-butadiene are preferred.

In the above polymerization, only a conjugated diene compound may be used. From the viewpoint of increasing the strength of the resulting crosslinked rubber, the polymer (A) is a copolymer of a conjugated diene compound and an aromatic vinyl compound. preferable. Examples of the aromatic vinyl compound used for polymerization include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4 -T-butylstyrene, 5-t-butyl-2-methylstyrene, vinylethylbenzene, divinylbenzene, trivinylbenzene, divinylnaphthalene, t-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl) dimethylaminoethyl ether N, N-dimethylaminoethylstyrene, N, N-dimethylaminomethylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2-t-butylstyrene, 3-t-butylstyrene, 4- t-butyl styrene, vinyl xylene, Sulfonyl naphthalene, vinyl pyridine, diphenylethylene, tertiary amino group-containing diphenylethylene (e.g., 1- (4-N, N- dimethylaminophenyl) -1-phenylethylene, etc.) and the like. Of these, styrene and α-methylstyrene are preferable as the aromatic vinyl compound.

In the case where the conjugated diene polymer in the present disclosure is a copolymer of a conjugated diene compound and an aromatic vinyl compound, 1,3-butadiene and styrene are used as the monomer composition in terms of high living property in anionic polymerization. It is preferable that the polymer is contained in The copolymer preferably has a random copolymer portion in which the distribution of the conjugated diene compound and the aromatic vinyl compound is irregular. The copolymer may further have a block portion made of a conjugated diene compound or an aromatic vinyl compound.

When the conjugated diene polymer is a copolymer of a conjugated diene compound and an aromatic vinyl compound, the proportion of the aromatic vinyl compound used is a balance between the low hysteresis loss characteristics of the resulting crosslinked rubber and the wet skid resistance. From the viewpoint of improving the viscosity, the content is preferably 3 to 55 mass%, more preferably 5 to 50 mass%, based on the total amount of the conjugated diene compound and the aromatic vinyl compound used for the polymerization. The content ratio of the structural unit derived from the aromatic vinyl compound in the polymer is a value measured by ¹ H-NMR. A conjugated diene compound and an aromatic vinyl compound may be used individually by 1 type, respectively, and may be used in combination of 2 or more type.

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

As the polymerization method to be used, any of solution polymerization method, gas phase polymerization method and bulk polymerization method may be used, but the solution polymerization method is particularly preferable. Moreover, as a polymerization form, you may use any of a batch type and a continuous type. When using the solution polymerization method, an example of a specific polymerization method is a method in which a monomer containing a conjugated diene compound is polymerized in an organic solvent in the presence of a polymerization initiator and a randomizer used as necessary. Can be mentioned.

As the polymerization initiator, at least one of an alkali metal compound and an alkaline earth metal compound can be used. Specific examples thereof include, for example, methyllithium, ethyllithium, n-propyllithium, n-butyllithium, sec-butyllithium, alkyllithium such as t-butyllithium, 1,4-dilithiobutane, phenyllithium, stilbenelithium, Naphthyl lithium, 1,3-bis (1-lithio-1,3-dimethylpentyl) benzene, 1,3-phenylenebis (3-methyl-1-phenylpentylidene) dilithium, naphthyl sodium, naphthyl potassium, di-n -Butylmagnesium, di-n-hexylmagnesium, ethoxypotassium, calcium stearate and the like. Of these, lithium compounds are preferred. The total amount of the polymerization initiator used is preferably 0.2 to 20 mmol with respect to 100 g of the monomer used for the polymerization.

The polymerization reaction may be performed using, as a polymerization initiator, a mixture of at least one of an alkali metal compound and an alkaline earth metal compound and a compound having a functional group that interacts with silica. By carrying out the polymerization in the presence of the mixture, the polymerization initiation terminal of the conjugated diene polymer can be modified with a functional group that interacts with silica. In the present specification, the “functional group that interacts with silica” means a group having an element that interacts with silica, such as nitrogen, sulfur, phosphorus, and oxygen. “Interaction” refers to an intermolecular force that forms a covalent bond between molecules or is weaker than a covalent bond (eg, ion-dipole interaction, dipole-dipole interaction, hydrogen bond, van der Waals This means that an electromagnetic force between molecules such as force is formed.

As the compound having a functional group that interacts with silica used for modification of the polymerization initiation terminal, a nitrogen-containing compound such as a secondary amine compound is preferable. Specific examples of the nitrogen-containing compound include, for example, dimethylamine, diethylamine, dipropylamine, dibutylamine, dodecamethyleneimine, N, N′-dimethyl-N′-trimethylsilyl-1,6-diaminohexane, piperidine, pyrrolidine, Hexamethyleneimine, heptamethyleneimine, dicyclohexylamine, N-methylbenzylamine, di- (2-ethylhexyl) amine, diallylamine, morpholine, N- (trimethylsilyl) piperazine, N- (tert-butyldimethylsilyl) piperazine, 1, Examples include 3-ditrimethylsilyl-1,3,5-triazinane.

In the above polymerization, at least one of an alkali metal compound and an alkaline earth metal compound and a compound having a functional group that interacts with silica are mixed in advance, and the mixture is added to the polymerization system to perform polymerization. May be performed. Alternatively, at least one of an alkali metal compound and an alkaline earth metal compound and a compound having a functional group that interacts with silica may be added to the polymerization system, and polymerization may be performed by mixing both in the polymerization system. Good.

The randomizer can be used for the purpose of adjusting the vinyl bond content representing the vinyl bond content in the polymer. Examples of randomizers include dimethoxybenzene, tetrahydrofuran, dimethoxyethane, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, 2,2-di (tetrahydrofuryl) propane, 2- (2-ethoxyethoxy) -2-methylpropane, triethylamine, pyridine N-methylmorpholine, tetramethylethylenediamine and the like. These can be used individually by 1 type or in combination of 2 or more types.

The organic solvent used for the polymerization may be an organic solvent inert to the reaction, and for example, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons and the like can be used. Among these, hydrocarbons having 3 to 8 carbon atoms are preferable, and specific examples thereof include, for example, propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, cyclohexane, propene, 1-butene and isobutene. , Trans-2-butene, cis-2-butene, 1-pentyne, 2-pentyne, 1-hexene, 2-hexene, benzene, toluene, xylene, ethylbenzene, heptane, cyclopentane, methylcyclopentane, methylcyclohexane, 1 -Pentene, 2-pentene, cyclohexene and the like. In addition, as an organic solvent, 1 type can be used individually or in combination of 2 or more types.

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

By such a polymerization reaction, a conjugated diene polymer having an active end can be obtained. In the conjugated diene polymer obtained, the vinyl bond content in the butadiene unit is preferably 20 to 70% by mass, more preferably 23 to 68% by mass, and further preferably 25 to 65% by mass. preferable. When the vinyl bond content is less than 20% by mass, the grip characteristics tend to be low, and when it exceeds 70% by mass, the wear resistance of the resulting vulcanized rubber tends to decrease. In the present specification, the “vinyl bond content” is a value indicating the content ratio of structural units having 1,2-bonds to all structural units of butadiene in the conjugated diene polymer. ¹ H-NMR Is a value measured by.

(Hydrogenation process)
In this step, the conjugated diene polymer obtained by the polymerization step is hydrogenated (hydrogenated). The method and conditions for hydrogenation are not particularly limited as long as a polymer having a desired hydrogenation rate can be obtained. As an example of the hydrogenation method, a method using a catalyst mainly composed of an organometallic compound of titanium as a hydrogenation catalyst, a catalyst comprising an organometallic compound of iron, nickel, cobalt and an organometallic compound such as alkylaluminum is used. A method using an organic complex of an organometallic compound such as ruthenium or rhodium, a method using a catalyst in which a metal such as palladium, platinum, ruthenium, cobalt or nickel is supported on a carrier such as carbon, silica or alumina. is there. Among various methods, a homogeneous catalyst composed of an organometallic compound of titanium alone or an organometallic compound of lithium, magnesium, and aluminum (Japanese Patent Publication No. 63-4841 and Japanese Patent Publication No. 1-337970) is used. The hydrogenation method under mild conditions of low pressure and low temperature is industrially preferable, and the hydrogenation selectivity to the double bond derived from butadiene is high, which is suitable for the purpose of the present disclosure.

Hydrogenation is carried out in a solvent that is inert to the catalyst and in which the conjugated diene polymer is soluble. Preferred solvents include aliphatic hydrocarbons such as n-pentane, n-hexane and n-octane, alicyclic hydrocarbons such as cyclohexane and cycloheptane, aromatic hydrocarbons such as benzene and toluene, diethyl ether , Ethers such as tetrahydrofuran alone or a mixture containing them as a main component.

In the hydrogenation reaction, the polymer is generally held at a predetermined temperature in hydrogen or an inert atmosphere, a hydrogenation catalyst is added with stirring or under stirring, and hydrogen gas is then introduced to increase the pressure. It is carried out by pressing. The inert atmosphere means an atmosphere that does not react with any participant in the hydrogenation reaction, and is formed of, for example, helium, neon, argon, or the like. As a hydrogenation reaction process for obtaining a hydrogenated conjugated diene polymer, any of a batch process, a continuous process, and a combination thereof may be used. The addition amount of the hydrogenation catalyst is preferably 0.02 to 20 mmol per 100 g of the conjugated diene polymer before hydrogenation.

In the polymer (A), the hydrogenation rate of the structural unit derived from butadiene contained in the polymer (A) is in the range of 60 to 90%. When the hydrogenation rate of the polymer (A) is 60% or more, a crosslinked rubber having sufficiently high mechanical strength (tensile strength) and elongation at break can be obtained. The lower limit of the hydrogenation rate is preferably 63% or more, more preferably 65% or more, and even more preferably 68% or more, in that the tensile strength of the resulting crosslinked rubber can be sufficiently increased. The upper limit of the hydrogenation rate is 90% or less and 85% or less from the viewpoint of suppressing the reduction in production efficiency and realizing low cost while sufficiently securing the tensile strength of the crosslinked rubber. It is preferable to make it 80% or less. The hydrogenation rate is a value measured by ¹ H-NMR. The hydrogenation rate can be arbitrarily selected by changing the amount of the hydrogenation catalyst, the hydrogen pressure during the hydrogenation reaction, and the reaction time.

The hydrogenated conjugated diene polymer of the present disclosure can be obtained by removing the solvent from the solution obtained above and isolating the polymer. The polymer can be isolated by a known desolvation method such as steam stripping and a drying operation such as heat treatment.

The polymer (A) may be an unmodified conjugated diene polymer, but has an amino group and a carbon-nitrogen double bond from the viewpoint of improving the dispersibility of silica and improving the low hysteresis loss characteristic. A modified polymer having at least one functional group selected from the group consisting of a group, a nitrogen-containing heterocyclic group, a phosphino group, a thiol group, and a hydrocarbyloxysilyl group (hereinafter also referred to as “specific functional group”). preferable. The modification method is not particularly limited. For example, [1] a method using a mixture of at least one of an alkali metal compound and an alkaline earth metal compound and a compound having a specific functional group as a polymerization initiator, [2] the above polymerization Examples thereof include a method of reacting a conjugated diene polymer having an active end obtained by the step with a compound having a specific functional group. Among them, it is preferable to use the method [2] alone or to use the method [1] and the method [2] in combination. In this case, the polymer (A) is preferably a reaction product of an active terminal of the conjugated diene polymer and a compound having a specific functional group and capable of reacting with the active terminal of the conjugated diene polymer. It is a hydrogenated conjugated diene polymer added.

(Terminal denaturation step)
In the method [2], the compound to be reacted with the polymer having an active end is a compound having a specific functional group and capable of reacting with the active end of a conjugated diene polymer (hereinafter referred to as “compound (C)”. As long as it is also referred to). Preferable specific examples of the compound (C) include the following (I) to (III).

（式（２ａ）中、Ａ^１は、窒素原子、リン原子及び硫黄原子からなる群より選択される少なくとも一種の原子を有し、活性水素を有さず、かつＲ^５に対して窒素原子、リン原子又は硫黄原子で結合する１価の官能基である。Ｒ^３及びＲ^４はヒドロカルビル基であり、Ｒ^５はヒドロカルビレン基であり、ｎは０～２の整数である。但し、Ｒ^３及びＲ^４が複数存在する場合、複数のＲ^３及びＲ^４は、それぞれ同じでも異なっていてもよい。） (I) Compound (C-1) represented by the following formula (2a);

(In Formula (2a), A ¹ has at least one atom selected from the group consisting of a nitrogen atom, a phosphorus atom, and a sulfur atom, does not have active hydrogen, and is a nitrogen atom with respect to R ⁵ ; A monovalent functional group bonded with a phosphorus atom or a sulfur atom, R ³ and R ⁴ are hydrocarbyl groups, R ⁵ is a hydrocarbylene group, and n is an integer of 0 to 2, provided that R When a plurality of ³ and R ⁴ are present, the plurality of R ³ and R ⁴ may be the same or different.)

(II) In the molecule, a functional group G ¹ which is at least one selected from the group consisting of a cyclic ether group, a (thio) carbonyl group and an iso (thio) cyanate group, a nitrogen atom, a phosphorus atom, an oxygen atom, and At least one atom selected from the group consisting of sulfur atoms (provided that at least one of the nitrogen atom, phosphorus atom and sulfur atom may be protected by a tri-substituted hydrocarbylsilyl group); A compound (C-2) having no active hydrogen and each having one or more groups G ² different from the functional group G ¹ ;
(III) Compound (C-3) having two or more iso (thio) cyanate groups in the molecule;

In the present specification, the (thio) carbonyl group represents a carbonyl group and a thiocarbonyl group, and the iso (thio) cyanate group represents an isocyanate group and an isothiocyanate group. As a compound (C), said 1 type can be used individually or in combination of 2 or more types.

In the above formula (2a), the hydrocarbyl group of R ³ and R ⁴ is a linear or branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or an aryl having 6 to 20 carbon atoms. It is preferably a group.
R ⁵ is preferably a linear or branched alkanediyl group having 1 to 20 carbon atoms, a cycloalkylene group having 3 to 20 carbon atoms, or an arylene group having 6 to 20 carbon atoms.
n is preferably 0 or 1 from the viewpoint of increasing the reactivity with the conjugated diene polymer.
A ¹ has at least one atom selected from the group consisting of a nitrogen atom, a phosphorus atom and a sulfur atom, and is bonded to R ⁵ with a nitrogen atom, a phosphorus atom or a sulfur atom. The nitrogen atom, phosphorus atom and sulfur atom in A ¹ are not bonded to active hydrogen and may be protected with a protecting group.

In the present specification, “active hydrogen” refers to a hydrogen atom bonded to an atom other than a carbon atom, preferably one having a bond energy lower than the carbon-hydrogen bond of polymethylene. The “protecting group” is a functional group that converts A ¹ into a functional group that is inactive with respect to the polymerization active terminal, and examples thereof include a trisubstituted hydrocarbylsilyl group.

In particular, A ¹ is preferably a group capable of becoming an onium ion by the onium salt generator. When the compound (C) has such a group (A ¹ ), the resulting hydrogenated conjugated diene polymer has excellent shape retention.
Specific examples of A ¹ include, for example, a nitrogen-containing group in which two hydrogen atoms of a primary amino group are substituted by two protecting groups, and one hydrogen atom of a secondary amino group is substituted by one protecting group. A phosphorus-containing group in which two hydrogen atoms of a nitrogen-containing group, a tertiary amino group, a group having a carbon-nitrogen double bond, a nitrogen-containing heterocyclic group, and a primary phosphino group are substituted by two protecting groups, Phosphorus-containing groups in which one hydrogen atom of a tertiary phosphino group is substituted by one protecting group, sulfur-containing groups in which one hydrogen atom of a thiol group is substituted by one protecting group, etc. Is mentioned. Among these, a group having a nitrogen atom is preferable from the viewpoint of good affinity with silica. The protecting group is not particularly limited, and examples thereof include a trisubstituted hydrocarbylsilyl group.

Specific examples of the compound (C-1) include a nitrogen-containing group in which two hydrogen atoms of a primary amino group are substituted by two protecting groups, and one hydrogen atom of a secondary amino group is substituted by one protecting group. Examples of the compound having a substituted nitrogen-containing group or tertiary amino group and an alkoxysilyl group include N, N-bis (trimethylsilyl) aminopropyltrimethoxysilane and N, N-bis (trimethylsilyl) aminopropylmethyl. Diethoxysilane, N, N ′, N′-tris (trimethylsilyl) -N- (2-aminoethyl) -3-aminopropyltriethoxysilane, 3- (4-trimethylsilyl-1-piperazino) propylmethyldimethoxysilane, And the alkyl group and alkanediyl group in these compounds are each an alkyl group having 1 to 6 carbon atoms, Compounds obtained by replacing the alkanediyl group ~ 6.

Examples of the compound having a group having a carbon-nitrogen double bond or a nitrogen-containing heterocyclic group and an alkoxysilyl group include N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1 -Propanamine, N- (1-methylpropylidene) -3- (triethoxysilyl) -1-propanamine, N- (4-N, N-dimethylaminobenzylidene) -3- (triethoxysilyl) -1 -Propanamine, N- (cyclohexylidene) -3- (triethoxysilyl) -1-propanamine, N- (3-trimethoxysilylpropyl) -4,5-dihydroimidazole, N- (3-trimethoxy Silylpropyl) imidazole, 3-hexamethyleneiminopropyltrimethoxysilane, 3-hexamethyleneiminopropylmethyldimethoxysilane 3- (1-piperidino) propyltrimethoxysilane, 3- (1-hexamethyleneimino) propyltrimethoxysilane, 3- (1-piperazinyl) propyltrimethoxysilane, 3-morpholinopropyltrimethoxysilane, and these And compounds in which the alkyl group and alkanediyl group in the compound are replaced with alkyl groups having 1 to 6 carbon atoms and alkanediyl groups having 1 to 6 carbon atoms, respectively.

A phosphorus-containing group in which two hydrogen atoms of a primary phosphino group are substituted by two protecting groups, a phosphorus-containing group in which one hydrogen atom of a secondary phosphino group is substituted by one protecting group, a tertiary phosphino group As a compound having a sulfur-containing group in which one hydrogen atom of a thiol group is substituted with one protecting group and an alkoxysilyl group, for example, P, P-bis (trimethylsilyl) phosphinopropylmethyldimethoxysilane , P, P-bis (trimethylsilyl) phosphinopropyltrimethoxysilane, 3-dimethylphosphinopropyltrimethoxysilane, 3-dimethylphosphinopropylmethyldimethoxysilane, 3-diphenylphosphinopropyltrimethoxysilane, 3-diphenylphos Finopropylmethyl dimethoxy Silane, S-trimethylsilyl mercaptopropylmethyldimethoxysilane, S-trimethylsilylmercaptopropyltrimethoxysilane, and alkyl groups and alkanediyl groups in these compounds are each an alkyl group having 1 to 6 carbon atoms and an alkyl group having 1 to 6 carbon atoms. Examples include compounds substituted with alkanediyl groups. Examples of the compound having an iso (thio) cyanate group include 3-isocyanatopropyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane.

In the compound (C-2), the group G ² is preferably a group containing a nitrogen atom not bonded to active hydrogen. Specific examples of the compound (C-2) in this case include compounds having a cyclic ether group such as an epoxyamine compound such as tetraglycidyl-1,3-bisaminomethylcyclohexane, and the like;
Examples of compounds having a (thio) carbonyl group include 4-aminoacetophenone such as 4-N, N-dimethylaminobenzophenone; bis (dihydrocarbylaminoalkyl) such as 1,7-bis (methylethylamino) -4-heptanone Ketone: dihydrocarbylaminoalkyl (meth) acrylate such as 2-dimethylaminoethyl acrylate;
Hydrocarbyl imidazolidinone such as 1,3-dimethyl-2-imidazolidinone; N-hydrocarbyl pyrrolidone such as 1-phenyl-2-pyrrolidone; N-hydrocarbyl captolactam such as N-methyl-ε-caprolactam; N N-dihydrocarbylformamide such as N, N-diethylformamide; N, N-dihydrocarbylacetamide such as N, N-dimethylacetamide; (meth) acrylamide such as N, N-dimethylacrylamide; etc .; iso (thio) cyanate Examples of the compound having a group include 3-isocyanatopropyltrimethoxysilane and the like.

Examples of the compound (C-3) include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, p-phenylene diisocyanate. Narate, tris (isocyanatophenyl) thiophosphate, xylene diisocyanate, benzene-1,2,4-triisocyanate, naphthalene-1,2,5,7-tetraisocyanate, 1,4-phenylenediisothiocyanate Narts can be mentioned.

As the compound (C), it is particularly preferable to use the compound (C-1) because it has a strong affinity for silica. When using the compound (C-1), for the purpose of adjusting the Mooney viscosity of the modified conjugated diene polymer, together with the compound (C-1), silicon tetrachloride, an epoxy-containing compound (for example, tetraglycidyl-1, A coupling agent such as 3-bisaminomethylcyclohexane may be used in combination. As a compound (C), these 1 type can be used individually or in combination of 2 or more types.

The reaction between the polymer having an active terminal and the compound (C) can be performed, for example, as a solution reaction. This solution reaction may be carried out using a solution containing unreacted monomers after the completion of the polymerization reaction. The conjugated diene polymer contained in the solution is isolated and dissolved in a suitable solvent such as cyclohexane. You may go. Moreover, you may perform the said reaction using any of a batch type and a continuous type. At this time, the addition method of the compound (C) is not particularly limited, and examples thereof include a batch addition method, a divided addition method, and a continuous addition method. The terminal modification reaction is preferably performed before the hydrogenation step.

In the above reaction, the proportion of compound (C) used may be appropriately set according to the type of compound (C), but is preferably 0.1 mol relative to the metal atom involved in the polymerization reaction of the polymerization initiator. Equivalent or more, more preferably 0.3 molar equivalent or more. By setting it to 0.1 molar equivalent or more, the reaction can sufficiently proceed, and the dispersibility of silica can be suitably improved. Further, in terms of reducing unreacted substances in the solution after the modification reaction, the use ratio of the compound (C) is less than 1.2 molar equivalents with respect to the metal atoms involved in the polymerization reaction of the polymerization initiator. It is preferable to make it less than 1.0 molar equivalent. The temperature of the above reaction is usually the same as the temperature of the polymerization reaction, preferably −20 ° C. to 150 ° C., more preferably 0 to 120 ° C., and particularly preferably 20 to 100 ° C. . When the reaction temperature is low, the viscosity of the modified conjugated diene polymer tends to increase. On the other hand, when the reaction temperature is high, the polymerization active terminal tends to be deactivated. The reaction time is preferably 1 minute to 5 hours, more preferably 2 minutes to 1 hour.

In order to obtain a polymer (A) having a desired molecular weight, a coupling agent may be reacted with the polymer having an active terminal obtained in the polymerization step. The coupling agent is not particularly limited. For example, succinic acid amide, phthalic acid amide, dibenzoylpyridine, dibutyldichlorosilicon, methyltrichlorosilicon, methyldichlorosilicon, tetrachlorosilicon (silicon tetrachloride), silicon tetrabromide , Silicon tetraiodide, trichloromethoxysilane, tribromomethoxysilane, trimethoxysilane, methyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, dimethyl adipate, dimethyl terephthalate, tetrachlorotin, tetrabromotin, trichlorobutyltin , Trichloromethyltin, trichloroethyltin, trichlorophenyltin, trichlorooctyltin, butyltin trisoctanoate, dibutyltin bislaurate, ethylene glycol diglycidyl Ether, trichloromethyl phosphine, pyromellitic anhydride, divinylbenzene, trichloropropane, and the like. In addition, a coupling agent can be used individually by 1 type or in combination of 2 or more types.

The reaction between the polymerization active terminal and the coupling agent can be performed, for example, as a solution reaction. In the reaction, the amount of the coupling agent to be used is preferably 0.1 molar equivalent or more, more preferably 0.1 mol equivalent to the metal atom involved in the polymerization reaction of the polymerization initiator, from the viewpoint of sufficiently proceeding the reaction. 3 molar equivalents or more. Moreover, it is preferable to set it as less than 1.2 molar equivalent with respect to the metal atom which participates in the polymerization reaction which a polymerization initiator has, and, as for the usage-amount of a coupling agent, it is more preferable to set it as less than 1.0 molar equivalent.

The weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) of the polymer (A) is the tensile strength, low fuel consumption performance and wear resistance of the resulting crosslinked rubber, and processability of the rubber composition. From the point of view, it is 1.0 × 10 ⁵ to 2.0 × 10 ⁶ . When Mw is smaller than 1.0 × 10 ⁵ , the resulting crosslinked rubber has poor tensile strength, low fuel consumption performance and wear resistance, and when it is larger than 2.0 × 10 ⁶ , the rubber composition has poor workability. . More preferably, it is 1.3 × 10 ⁵ to 1.5 × 10 ⁶ , and still more preferably 1.5 × 10 ⁵ to 1.0 × 10 ⁶ . Examples of a method for obtaining the polymer (A) having a weight average molecular weight within the above range include a method in which the amount of the polymerization initiator relative to the amount of the monomer used is appropriately changed or a coupling agent is used. Although it is mentioned, it is not limited to these.

The polymer (A) obtained as described above is a hydrogenated conjugated diene polymer having a structural unit derived from a conjugated diene compound, the structural unit represented by the above formula (2), the above formula (3) ), The structural unit represented by the above formula (4), and the structural unit represented by the above formula (5) are represented by p, q, r, and s, respectively. Equation (6) is satisfied.
0.60 ≦ (p + r) / (p + q + r + s) ≦ 0.90 (6)
In addition, the said Numerical formula (6) represents that the hydrogenation rate of the structural unit derived from butadiene is 60% or more and 90% or less.

<(B) component>
The conjugated diene polymer (hereinafter also referred to as “polymer (B)”) as the component (B) has a structural unit derived from butadiene and has a hydrogenation rate different from that of the component (A). Or it is an unhydrogenated polymer. Specifically, the polymer (B) is not hydrogenated, that is, a conjugated diene polymer having a hydrogenation rate of 0% (hereinafter also referred to as “polymer (b-1)”), and butadiene. The hydrogenation rate of the derived structural unit is preferably at least one of hydrogenated conjugated diene polymers (hereinafter also referred to as “polymer (b-2)”) lower than that of the polymer (A). In this case, the polymer (B) is preferably a hydrogenated or non-hydrogenated conjugated diene system that satisfies the following formula (7) where (p + r) / (p + q + r + s) of the polymer (A) is θ. It is a polymer.
0 ≦ (p + r) / (p + q + r + s) <θ (7)
Among them, the polymer (b-1) is preferable as the polymer (B) in that a high-strength product can be produced at a lower cost. The polymer (B) is particularly preferably a copolymer of a conjugated diene compound and an aromatic vinyl compound.

The polymer (b-1) can be produced by a method including a polymerization step similar to that of the polymer (A). In addition, the polymer (b-2) can be produced by a method including a polymerization step and a hydrogenation step similar to those of the polymer (A). The polymer (B) may be either modified or non-modified, but an amino group and a carbon-nitrogen double bond are formed at one or both ends of the polymer in that the dispersibility of silica can be further improved. It preferably has at least one functional group (specific functional group) selected from the group consisting of a group having a nitrogen-containing heterocyclic group, a phosphino group, a thiol group, and a hydrocarbyloxysilyl group. For the details of the reaction conditions in the polymerization step and the terminal modification step for obtaining the polymer (B), the type and amount of the compound to be used, and preferred examples, description of the polymerization step and terminal modification step of the polymer (A) Applies.

Regarding the hydrogenation step for obtaining the polymer (b-2), the hydrogenation rate of the polymer (b-2) is such that the crosslinking with the polymer (A) is sufficiently advanced to obtain a high strength crosslinked rubber. From the viewpoint of producing the crosslinked rubber more inexpensively, it is preferably more than 0% and less than 55%, more preferably 1 to 50%, and further preferably 1 to 20%. For details of the hydrogenation method and conditions, the description of the hydrogenation step of the polymer (A) is applied. The difference in the hydrogenation rate between the polymer (A) and the polymer (B) is preferably 20% or more, more preferably 50% or more, and further preferably 70% or more.

For the polymer (B), the weight average molecular weight in terms of polystyrene by GPC is preferably 1.0 × 10 ⁵ to 2.0 × 10 ⁶ . When it is 1.0 × 10 ⁵ or more, it is preferable from the viewpoint that the tensile strength of the obtained crosslinked rubber can be sufficiently increased, and when it is 2.0 × 10 ⁶ or less, it is preferable from the viewpoint of better workability. The lower limit of the weight average molecular weight of the polymer (B) is preferably 1.0 × 10 ⁵ or more, more preferably 1.5 × 10 ⁵ or more. Moreover, an upper limit becomes like this. Preferably it is 1.5 * 10 < ⁶ > or less, More preferably, it is 1.0 * 10 < ⁶ > or less. In addition, a polymer (B) can be used individually by 1 type or in combination of 2 or more types.

Regarding the content ratio of the polymer (A) and the polymer (B) in the rubber composition of the present disclosure, the content ratio of the polymer (A) with respect to 100 parts by mass of the polymer (B) is 5 to 500 parts by mass. Such an amount is preferable. If the content is less than 5 parts by mass, the resulting crosslinked rubber tends to have low tensile strength. If the content is more than 500 parts by mass, the price of the product may not be sufficiently reduced. The content ratio of the polymer (A) is more preferably 10 to 450 parts by weight, still more preferably 15 to 400 parts by weight with respect to 100 parts by weight of the polymer (B).
The blending ratio (mass ratio) of the polymer (A) and the polymer (B) is not particularly limited as long as the co-vulcanization parameter is a value within the above range, but high tensile strength and low cost are well balanced. From the standpoint of expression, when the total amount of the polymer (A) and the polymer (B) is 1, the polymer (A): polymer (B) (that is, α: β) is 0.1 to 0. .9: Preferably 0.9 to 0.1. α: β is more preferably 0.2 to 0.8: 0.8 to 0.2, and still more preferably 0.4 to 0.6: 0.6 to 0.4. The total amount of the polymer (A) and the polymer (B) in the rubber composition is preferably 20 to 70% by mass, and preferably 30 to 65% by mass with respect to the total amount of the rubber composition. It is more preferable.

<(C) component>
Examples of the silica blended in the rubber composition include wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), colloidal silica, precipitated silica, calcium silicate, and aluminum silicate. Of these, wet silica is particularly preferred from the viewpoint of the effect of improving the fracture resistance and the effect of achieving both wet grip properties and low rolling resistance. It is also preferable to use high-dispersion type silica from the viewpoint of improving dispersibility in the polymer composition and improving physical properties and processability. Silica can be used alone or in combination of two or more.

The compounding amount of silica in the rubber composition is preferably 1 to 100 parts by mass with respect to 100 parts by mass of the total amount of the polymer components. When the amount is less than 1 part by mass, it is difficult to obtain the effect of improving the fracture resistance by silica, and when the amount is more than 100 parts by mass, the workability and elongation at break tend to decrease. The orientation ratio of silica is more preferably 5 to 95 parts by mass, still more preferably 10 to 90 parts by mass.

<(D) component>
A crosslinking agent is blended in the rubber composition. Examples of the crosslinking agent include sulfur, sulfur halides, organic peroxides, quinonedioximes, organic polyvalent amine compounds, alkylphenol resins having a methylol group, and sulfur is usually used. The blending ratio of sulfur is preferably 0.1 to 5 with respect to 100 parts by mass of the total amount of the polymer components contained in the rubber composition from the viewpoint of obtaining a crosslinked rubber having various properties such as elasticity and tensile strength. Part by mass, more preferably 0.3 to 3 parts by mass.

<Other ingredients>
The rubber composition of the present disclosure may contain other components other than the polymer (A), the polymer (B), silica, and a crosslinking agent. For example, in addition to the polymer (A) and polymer (B) obtained above, other rubber components may be blended in the rubber composition. The type of the rubber component is not particularly limited, and examples thereof include natural rubber (NR), isoprene rubber (IR), and styrene isoprene copolymer rubber. The blending ratio of the other rubber component is preferably 30 parts by mass or less, more preferably 10 parts by mass or less, with respect to 100 parts by mass in total of the polymer components contained in the rubber composition.

The rubber composition may contain a reinforcing filler other than silica. Examples of such reinforcing fillers include carbon black, clay, calcium carbonate and the like. The reinforcing filler blended in the rubber composition of the present disclosure is preferably silica alone or a combination of carbon black and silica. When carbon black is used in combination, the blending ratio of carbon black is preferably 20% by mass or less, and more preferably 10% by mass or less, based on the total amount of silica and carbon black in the rubber composition. preferable.

Further, the rubber composition may be blended with a process oil generally used for oil-extended elastomer as an oil for oil-extended. Process oils are formulated into rubber compositions, for example, by adding oil directly during rubber compounding. Preferred process oils include various oils known in the art, such as aromatic oils, paraffinic oils, naphthenic oils, vegetable oils, and oils with a low content of polycyclic aromatic compounds (low PCA oil), for example, mild extract solvate (MES), oil treated with aromatic extract from distillate (TDAE), aromatic special extract from residual oil Products (SRAE), heavy naphthenic oils, and the like. Examples of commercially available MES, TDAE, and SRAE include Shellex Catenex® SNR (heavy paraffin obtained by dewaxing distillate with a solvent) as MES, V & tec® 500 manufactured by H & R® Wasag® AG as TDAE, and Japan® Energy® Corp as SRAE. NC140 made by. The blending amount of the process oil is preferably 10 to 100 parts by mass with respect to 100 parts by mass of the total amount of the polymer components contained in the rubber composition.

In addition to the components described above, the rubber composition includes, for example, anti-aging agent, zinc white, stearic acid, softener, vulcanization accelerator, silane coupling agent, compatibilizer, vulcanization aid, processing aid, Various additives generally used in rubber compositions such as extender oil and scorch inhibitor can be blended. These blending ratios can be appropriately selected according to various components within a range not impairing the effects of the present disclosure.

The rubber composition for obtaining the crosslinked rubber of the present disclosure has a co-vulcanization parameter represented by the above formula (1) of 0.85 or more. By using a rubber composition having a co-vulcanization parameter of 0.85 or more, a high-strength crosslinked rubber that exhibits good tensile strength and good elongation at break in a balanced manner can be obtained. In addition, in the rubber composition in which two types of polymers are blended, it can be said that the larger the value of the co-vulcanization parameter, the better the co-vulcanizability of the two types of polymers. When the co-vulcanization parameter is less than 0.85, the resulting crosslinked rubber is inferior in that the tensile strength is low or the elongation at break is not sufficient. The co-vulcanization parameter is preferably 0.86 or more. Further, the upper limit value of the co-vulcanization parameter is not particularly limited, but is preferably 1.20 or less, more preferably 1.10 or less, from the viewpoint of suppressing a decrease in elongation at break and a sufficient cost reduction. . In this specification, the co-vulcanization parameters X and Y (torque difference) are temperatures at which a rubber composition is crosslinked by a vibration vulcanization tester in accordance with JIS-K6300-2 (crosslinking temperature). And the value measured under the conditions of an amplitude angle of ± 1 ° and a torsional frequency of 100 cpm.

The method for obtaining the rubber composition having the above-mentioned co-vulcanization characteristics is not particularly limited. For example, when the rubber composition is prepared, the blending ratio of the polymer (A) and the polymer (B) (α, β) is changed as appropriate, the temperature condition during crosslinking of the rubber composition is changed, the hydrogenation rate of the polymer (A) and the polymer (B) is changed, or two or more of these And the like. When the co-vulcanization parameter is 0.85 or more, crosslinking between the polymer (A) and the polymer (B) proceeds sufficiently, and the weight average molecular weight of the polymer (A) is 1. 0 × 10 ⁵ to 2.0 × 10 ⁶ is sufficiently high and the hydrogenation rate is sufficiently high as 60% or more, so that the crosslinked rubber obtained using the rubber composition has good tensile strength and good It is presumed that proper elongation at break could be expressed in a well-balanced manner.

<Cross-linked rubber and tire>
The crosslinked rubber of the present disclosure can be produced by kneading and crosslinking the rubber composition. That is, the rubber composition is composed of a polymer (A), a polymer (B), silica, and a crosslinking agent, as well as components blended as necessary, using an open kneader (for example, a roll), closed kneading. It can be applied to various rubber products as a crosslinked rubber by kneading using a kneading machine such as a machine (for example, a Banbury mixer) and crosslinking (vulcanizing) at a temperature of 120 to 180 ° C. after the molding process. Specifically, the crosslinked rubber of the present disclosure is used for tires such as tire treads, under treads, carcass, sidewalls, and bead parts; seal materials such as packings, gaskets, weather strips, O-rings; automobiles, ships, Interior and exterior skin materials for various vehicles such as aircraft and railways; Building materials; Anti-vibration rubbers for industrial machinery and equipment; Various hoses and hose covers such as diaphragms, rolls, radiator hoses and air hoses; Power transmission Belts such as industrial belts; linings; dust boots; medical equipment materials; fenders; insulating materials for electric wires; In particular, the crosslinked rubber obtained using the rubber composition is excellent in wet skid resistance, low hysteresis loss characteristics, tensile strength and wear resistance, and is preferably used as a material for tire treads and sidewalls. Can do.

The tire can be manufactured according to a conventional method. For example, a rubber composition is mixed with a kneader and formed into a sheet, and then placed at a predetermined position and vulcanized according to a conventional method to form a tread rubber or a sidewall rubber to obtain a pneumatic tire. It is done.

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. In the examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified. Moreover, the measuring method of various physical-property values is shown below.

[Bound styrene content (%)]: Determined by ¹ H-NMR measurement at 500 MHz.
[Weight-average molecular weight after modification]: Retention time corresponding to the peak of the maximum peak of the GPC curve obtained by using gel permeation chromatography (GPC) (HLC-8120GPC (trade name (manufactured by Tosoh Corporation))) Was calculated in terms of polystyrene.
(GPC conditions)
Column; two brand names "GMHXL" (manufactured by Tosoh Corporation)
Mobile phase; tetrahydrofuran flow rate; 1.0 ml / min sample concentration; 10 mg / 20 ml
[Hydrogenation rate (%)]: The hydrogenation rate of the butadiene unit was determined by ¹ H-NMR at 500 MHz.

<Synthesis of polymer>
[Synthesis Example 1]
An autoclave reactor with an internal volume of 50 liters purged with nitrogen was charged with 25800 g of cyclohexane, 201 g of tetrahydrofuran, 1462 g of styrene, and 2193 g of 1,3-butadiene. After the temperature of the reactor contents was adjusted to 40 ° C., a cyclohexane solution containing 2.84 g of n-butyllithium was added to initiate polymerization. Polymerization was carried out under adiabatic conditions.
When the temperature of the reactor contents reached 65 ° C., 645 g of butadiene was added over 15 minutes, and after further polymerizing for 3 minutes, 0.58 g of silicon tetrachloride was added. After 5 minutes, 6.8 g of [N, N-bis (trimethylsilyl) aminopropyl] methyldiethoxysilane was added and reacted for 15 minutes.
The reaction solution was brought to 80 ° C. or higher to introduce hydrogen into the system, and then 2.76 g of [bis (η5-cyclopentadienyl) titanium (furfuryloxy) chloride], 2.83 g of diethylaluminum chloride, and n -1.18 g of butyl lithium was added, and the reaction was carried out while maintaining the hydrogen pressure at 0.7 MPa or more until the hydrogenation rate reached 50%. After reaching a predetermined hydrogen equivalent amount flow rate, the reaction solution was returned to room temperature and normal pressure and extracted from the reaction vessel to obtain a polymer solution. The weight average molecular weight of the polymer measured by GPC was 200,000.
Subsequently, the solvent is removed by steam stripping (steam temperature: 190 ° C.) for 2 hours at a liquid phase temperature of 95 ° C. in the solvent removal tank, and the hydrogenation rate is achieved by drying with a hot roll adjusted to 110 ° C. 50% of conjugated diene polymer P was obtained. The polymerization formulation of the conjugated diene polymer P and the properties of the obtained hydrogenated conjugated diene polymer P are shown in Table 1 below.

[Synthesis Examples 2 to 6]
Except that the hydrogenation rate was changed as shown in Table 1 below, hydrogenated conjugated diene polymers Q to U were obtained in the same manner as in Synthesis Example 1. The properties of the obtained conjugated diene polymers Q to U are also shown in Table 1 below.

[Synthesis Example 7]
In the same manner as in Synthesis Example 1, polymerization of styrene and 1,3-butadiene and terminal modification with [N, N-bis (trimethylsilyl) aminopropyl] methyldiethoxysilane were performed.
Next, the solvent phase is removed by steam stripping (steam temperature: 190 ° C.) for 2 hours at a liquid phase temperature of 95 ° C. in the solvent removal tank, and drying is performed by a hot roll adjusted to 110 ° C. Polymer V was obtained. The weight average molecular weight of the polymer measured by GPC was 200,000. Table 1 below shows the polymerization formulation of the conjugated diene polymer V and the properties of the conjugated diene polymer V obtained.

[Synthesis Example 8]
The amount of n-butyllithium used was changed to 11.35 g, the amount of silicon tetrachloride used was changed to 2.32 g, and the amount of [N, N-bis (trimethylsilyl) aminopropyl] methyldiethoxysilane was changed to 27. Polymerization and terminal modification were carried out in the same manner as in Synthesis Example 1, except that the amount was changed to 4 g.
The reaction solution was brought to 80 ° C. or higher to introduce hydrogen into the system, and then 2.76 g of [bis (η5-cyclopentadienyl) titanium (furfuryloxy) chloride], 2.83 g of diethylaluminum chloride, and four 0.97 g of silicon chloride was added, and the reaction was carried out while maintaining the hydrogen pressure at 0.7 MPa or more until the hydrogenation rate reached 70%. After reaching a predetermined hydrogen equivalent amount flow rate, the reaction solution was returned to room temperature and normal pressure and extracted from the reaction vessel to obtain a polymer solution. The weight average molecular weight of the polymer measured by GPC was 50,000.
Next, the solvent is removed by steam stripping (steam temperature: 190 ° C.) for 2 hours at a liquid phase temperature of 95 ° C. in the solvent removal tank, and dried at 110 ° C. A conjugated diene polymer W having a rate of 70% was obtained. Table 1 below shows the polymerization formulation of the conjugated diene polymer W and the properties of the conjugated diene polymer W obtained.

[Synthesis Examples 9 and 10]
Except that the polymerization formulation was changed as shown in Table 1 below, hydrogenated conjugated diene polymers X and Y were obtained in the same manner as in Synthesis Example 1 above. The properties of the resulting conjugated diene polymers X and Y are also shown in Table 1 below.

In Table 1, the abbreviations of the terminal modifier and the catalyst used for hydrogenation are as follows. “-” Indicates that the compound in the corresponding column was not used.
Silane compound A: [N, N-bis (trimethylsilyl) aminopropyl] methyldiethoxysilane Silane compound B: 1- [3- (triethoxysilyl) propyl] -4-methylpiperazine Compound E: [bis (η5-cyclo Pentadienyl) titanium (furfuryloxy) chloride]
Compound F: diethylaluminum chloride

[Example 1]
(1) Production of rubber composition and crosslinked rubber Among polymer components, conjugated diene polymer Q having a hydrogenation rate of 60% obtained in Synthesis Example 2 as polymer (A), and polymer (B) Using the conjugated diene polymer V having a hydrogenation rate of 0% obtained in Synthesis Example 7 as described above, the respective components were blended according to the blending formulation shown in Table 2 below, and the resulting rubber composition was kneaded. Manufactured. The kneading was performed by the following method. Using a plastmill (internal volume: 250 ml) with a temperature controller, the first stage kneading (A kneading) was carried out under the conditions of a filling rate of 72% and a rotational speed of 60 rpm. ), Silica, silane coupling agent, extender oil, stearic acid, zinc oxide and anti-aging agent were blended and kneaded. Next, as the second stage kneading (B kneading), the blend obtained above was cooled to room temperature, and then a vulcanization accelerator and sulfur were blended and kneaded. This was molded and vulcanized with a vulcanization press at 160 ° C. (crosslinking temperature) for a predetermined time to obtain a crosslinked rubber.

(2) Evaluation of co-vulcanizability Using the rubber composition produced in (1) above as a measurement sample, a co-vulcanizability test was conducted to evaluate the co-vulcanizability of the polymer component in the rubber composition. . The co-vulcanization test was performed using a curast meter 7 (trade name) manufactured by JSR Trading Co., Ltd. First, after the die was heated to 160 ° C., 6 g of the measurement sample was set on the die, and vulcanized when the temperature was 160 ° C., the pressure was 490 kPa, the amplitude angle was ± 1 °, the torsional frequency was 100 cpm, and the vulcanization time was 30 minutes. From the curing curve, the minimum torque ML [dN-m] and the maximum torque MH [dN-m] were obtained, and the torque difference MH-MLΔ [dN-m] obtained by subtracting the minimum torque ML from the maximum torque MH was obtained. In this sample, ML = 3.2, MH = 18.3, and MH−MLΔ = 15.1 (see Table 2 below).
Separately, a rubber composition was produced with the same formulation as the above (1) except that the polymer V was replaced with the polymer Q (all the polymer components were changed to the polymer Q). A co-vulcanizability test was conducted using the product in the same manner as in (2) above. As a result, in the sample in which the polymer component was the polymer Q alone, ML = 3.2, MH = 20.5, and MH-MLΔ = 17.3 (see Table 4 and Reference Example 1 below).
Similarly, a rubber composition was produced by the same formulation as in the above (1) except that the blend of polymer Q was replaced with polymer V (all polymer components were polymer V), and the rubber composition obtained A co-vulcanizability test was conducted using the product in the same manner as in (2) above. As a result, in the sample in which the polymer component was the polymer V alone, ML = 3.1, MH = 17.4, and MH-MLΔ = 14.3 (see Table 4 and Reference Example 5 below).
Using these data, the value of the co-vulcanization parameter was calculated according to the above equation (1), which was 0.97 in this example.
Co-vulcanization parameter = 15.1 / (17.3 × 0.4 + 14.3 × 0.6) = 0.97

(3) Evaluation of tensile strength The obtained crosslinked rubber was used as a measurement sample, and the tensile strength at break (TB [MPa]) and elongation at break (EB [%]) were measured in accordance with JIS K6251: 2010. The measurement results show that the larger the value of TB, the harder it is to break and the higher the mechanical strength, and the larger the value of EB, the better the elongation (viscoelasticity). The results are shown in Table 2 below.

[Examples 2 to 13, Comparative Examples 1 to 3 and Comparative Example 5]
A rubber composition was produced in the same manner as in Example 1 except that the formulation was changed as shown in Tables 2 and 3 below, and a crosslinked rubber was produced by performing a crosslinking treatment. Further, physical properties were evaluated in the same manner as in Example 1 using the obtained rubber composition and crosslinked rubber. The results are shown in Tables 2 and 3 below.
[Comparative Example 4]
A rubber composition was produced in the same manner as in Example 1 except that the formulation was changed as described in Table 3 below, and a crosslinked rubber was produced by performing a crosslinking treatment at 200 ° C. Further, physical properties were evaluated in the same manner as in Example 1 using the obtained rubber composition and crosslinked rubber. The measurement temperature for the co-vulcanizability test was 200 ° C. The results are shown in Table 3 below.

In Tables 2 and 3, the trade names used for each component are as follows (the same applies to Tables 4 and 5 below). “-” Means that the compound in the corresponding column was not used.
* 1: ZEOSIL 1165MP manufactured by Rhodia, * 2: Si75 manufactured by Evonik, * 3: NXT Z45 manufactured by Momentive, * 4: Seest KH manufactured by Tokai Carbon Co., Ltd. * 5: T-DAE manufactured by JX Nippon Mining & Energy Distillate Aromatic Extract), * 6: Seiko Chemical Co., Ltd. Ozonon 6C, * 7: Ouchi Shinsei Chemical Industry Noxeller CZ, * 8: Ouchi Shinsei Chemical Industry Noxeller CZ-G, * 9: Ouchi Shinsei Chemical Industrial company Noxeller D, * 10: Kawaguchi Chemical Co., Ltd. Accel LUR.

From the results of Tables 2 and 3, in the rubber compositions using two kinds of conjugated diene polymers having different hydrogenation rates, according to Examples 1 to 13, tensile strength better than that of Comparative Examples 1 to 5 was obtained. It was found that the strength (TB) and the elongation at break (EB) were well-balanced, and a high-strength crosslinked rubber could be obtained. From these results, it can be said that according to the rubber composition of the example, a high-strength rubber can be produced at a low price.

[Reference Examples 1 to 19]
A rubber composition was produced in the same manner as in Example 1 except that the formulation was changed as shown in Tables 4 and 5 below, and a crosslinked rubber was produced by performing a crosslinking treatment. Further, physical properties were evaluated in the same manner as in Example 1 using the obtained rubber composition and crosslinked rubber. In Reference Examples 15 and 16, the production temperature (crosslinking temperature) of the crosslinked rubber and the measurement temperature of the co-vulcanizability test were 200 ° C. The results are shown in Tables 4 and 5 below.

Claims (5)

A crosslinked rubber obtained by crosslinking a rubber composition,
The rubber composition is
(A) The polystyrene-reduced weight average molecular weight by gel permeation chromatography is 1.0 × 10 ⁵ to 2.0 × 10 ⁶ , has a structural unit derived from butadiene, and is represented by the following formula (2). The structural ratios of the structural unit represented by the structural unit represented by the following formula (3), the structural unit represented by the following formula (4), and the structural unit represented by the following formula (5) are p, q, a hydrogenated conjugated diene polymer satisfying the following mathematical formula (6) when r and s:
0.60 ≦ (p + r) / (p + q + r + s) ≦ 0.90 (6)

(B) a hydrogenated or unhydrogenated conjugated diene polymer having a structural unit derived from butadiene and having a hydrogenation rate different from that of the component (A),
(C) silica, and (D) a crosslinking agent,
Containing
The crosslinked rubber whose co-vulcanization parameter represented by following Numerical formula (1) in the said rubber composition is 0.85 or more.
Co-vulcanization parameter = X / (Y × α + Z × β) (1)
(In Formula (1), α is the content ratio of the component (A) to the total amount of the component (A) and the component (B) in the rubber composition, and β is the rubber composition. It is the content ratio of the component (B) with respect to the total amount of the component (A) and the component (B), and satisfies the relationship of α + β = 1, where X is the rubber composition as a sample, This is the torque difference obtained by subtracting the minimum torque from the maximum torque measured in 30 minutes using a vibration type vulcanization tester under the conditions of a crosslinking temperature, an amplitude angle of ± 1 °, and a torsional frequency of 100 cpm. Y is the rubber It is the torque difference when the component (B) in the composition is replaced with the component (A) as a sample, and Z is the component (A) in the rubber composition (B ) The torque difference when the sample is replaced with a component. .) The component (B) is a hydrogenated or non-hydrogenated conjugated diene polymer that satisfies the following formula (7), where (p + r) / (p + q + r + s) of the component (A) is θ. Item 2. The crosslinked rubber according to Item 1.
0 ≦ (p + r) / (p + q + r + s) <θ (7) At least one of the component (A) and the component (B) is an amino group, a group having a carbon-nitrogen double bond, a nitrogen-containing heterocyclic group, a phosphino group, or a thiol group at one or both ends of the polymer. And a crosslinked rubber according to claim 1, which has one or more functional groups selected from the group consisting of hydrocarbyloxysilyl groups. The crosslinked rubber according to any one of Claims 1 to 3, wherein the weight average molecular weight in terms of polystyrene by gel permeation chromatography of the component (B) is 1.0 × 10 ⁵ to 2.0 × 10 ^6. . A tire having at least a tread or a sidewall formed by the crosslinked rubber according to any one of claims 1 to 4.