WO2023171628A1

WO2023171628A1 - Polymer composition and method for producing same, crosslinked product, and tire

Info

Publication number: WO2023171628A1
Application number: PCT/JP2023/008379
Authority: WO
Inventors: 利充菊池; 寛文千賀; 龍源中濱; 天斗福本; 拓哉佐野; 俊之早川
Original assignee: 株式会社Ｅｎｅｏｓマテリアル
Priority date: 2022-03-08
Filing date: 2023-03-06
Publication date: 2023-09-14
Also published as: TW202346387A

Abstract

Provided is a polymer composition containing: (A) a conjugated diene polymer having a structural unit derived from a conjugated diene compound and a structural unit derived from an aromatic vinyl compound, the value α of the conjugated diene polymer, as represented by mathematical expression (i), is 0.60-0.98, where the composition ratio (molar ratio) in the polymer of the structural units represented by formulas (1), (2), (3) and (4) are p, q, r, s respectively; and (B) a hindered phenol compound having a molecular weight of 250-2000. A portion or all of the component (A) has a functional group including at least one element selected from the group consisting of nitrogen, oxygen, sulfur, and phosphorous.　α = (p + (0.5 × r)) / (p + q + (0.5 × r) + s) ... (i)

Description

Polymer composition, method for producing the same, crosslinked product, and tire

[Cross reference to related applications]
This application claims priority based on Japanese Patent Application No. 2022-35722 filed on March 8, 2022, which is incorporated herein by reference in its entirety.
The present disclosure relates to a polymer composition, a method for producing the same, a crosslinked product, and a tire.

Conjugated diene polymers obtained by polymerization using conjugated diene compounds have good properties such as heat resistance, abrasion resistance, mechanical strength, and moldability, so they are used in pneumatic tires, anti-vibration rubber, Widely used in various industrial products such as hoses.

Polymer compositions used to manufacture pneumatic tire treads, sidewalls, etc. contain conjugated diene polymers as well as reinforcing agents such as carbon black and silica to improve product durability and wear resistance. It is known to incorporate inorganic fillers. Furthermore, conventionally, in order to increase the affinity between the conjugated diene polymer and the reinforcing agent, a conjugated diene polymer modified with a compound containing silicon or nitrogen has been used (for example, Patent Document 1 (See 3).

In addition, in recent years, hydrogenated conjugated diene polymers, which are hydrogenated products of conjugated diene polymers having functional groups such as amino groups or alkoxysilyl groups at one or both ends, have been developed to provide high strength and durability. It has been proposed to obtain a tire member with excellent wear resistance (see Patent Document 4).

International Publication No. 2008/123164 Japanese Patent Application Publication No. 11-349632 International Publication No. 2017/221943 International Publication No. 2014/133097

In the process of producing a conjugated diene polymer, when removing the solvent from a polymer solution containing the conjugated diene polymer to recover the conjugated diene polymer, a desolvation operation such as steam stripping is usually performed. . In this desolvation operation, it is difficult to strictly control the time for desolvation in the actual process. On the other hand, the quality of the polymer may not be stable due to variations in the time for desolvation, and there is concern that such quality instability may lead to deterioration in the performance of the crosslinked product. Considering this point, a polymer that can exhibit stable physical properties despite variations in the time for desolvation is desired.

However, when desolventizing a polymer solution containing a conjugated diene polymer into which functional groups have been introduced, the functional groups may react with each other or the functional groups themselves may be eliminated during the solvent removal process. It is assumed that radical side reactions such as these and side reactions with metal residues (for example, hydrogenation catalysts, etc.) may occur. Furthermore, there is a concern that the Mooney viscosity of the conjugated diene polymer is likely to change due to variations in the time for desolvation due to such side reactions occurring during desolvation.

In the manufacturing process of a conjugated diene polymer, adhesion of the conjugated diene polymer to equipment (for example, adhesion to a drying oven) often becomes a problem in the step of drying the conjugated diene polymer. If polymers tend to adhere to equipment, there are concerns that volatile matter derived from the polymer that adheres to and remains on the equipment may contaminate the equipment or cause heat storage combustion of the polymer that remains on the equipment. Therefore, it becomes necessary to frequently clean up the equipment, and there is a concern that the process load in the manufacturing process increases and productivity decreases.

The present disclosure has been made in view of the above-mentioned problems, and it is possible to reduce the process load and stabilize quality in the manufacturing process of a conjugated diene polymer, and to obtain a crosslinked product in which performance deterioration is suppressed. One object is to provide a polymer composition.

The present disclosure provides the following polymer composition, method for producing the same, crosslinked product, and tire.

[1] (A) A structural unit represented by the following formula (1), a structural unit represented by the following formula (2), a structural unit represented by the following formula (3), and a structural unit represented by the following formula (4). When the composition ratios (molar ratios) of the structural units in the polymer are p, q, r, and s, respectively, the value α expressed by the following formula (i) is 0.60 to 0.98, and the conjugated A conjugated diene polymer having a structural unit derived from a diene compound and a structural unit derived from an aromatic vinyl compound, and (B) a hindered phenol compound having a molecular weight of 250 to 2,000; ) A polymer composition in which some or all of the components have a functional group containing at least one element selected from the group consisting of nitrogen, oxygen, sulfur, and phosphorus.
α=(p+(0.5×r))/(p+q+(0.5×r)+s)
...(i)

[2] A crosslinked product obtained by crosslinking the polymer composition of [1] above.
[3] A tire in which a tread, a sidewall, or both are formed using the polymer composition of [1] above.
[4] A method for producing the polymer composition of [1] above, which comprises polymerizing a monomer containing a conjugated diene compound and an aromatic vinyl compound in the presence of an alkali metal or an alkaline earth metal, and hydrogenating the monomer. A step of obtaining a polymer solution containing the component (A) by mixing the polymer solution and the component (B) to form a mixture containing the component (A) and the component (B). A method for producing a polymer composition, comprising the steps of obtaining a liquid, and removing the solvent from the mixed liquid and drying it.

According to the present disclosure, it is possible to reduce the process load and stabilize the quality in the manufacturing process of a conjugated diene polymer. Furthermore, by stabilizing the quality of the conjugated diene polymer during the manufacturing process, a crosslinked product with suppressed performance deterioration can be obtained.

Hereinafter, matters related to implementation of the present disclosure will be explained in detail. In addition, in this specification, a numerical range described using "~" represents a range that includes the numerical values described before and after "~" as a lower limit value and an upper limit value.

《Polymer composition》
The polymer composition of the present disclosure (hereinafter also referred to as "the present composition") contains (A) a conjugated diene polymer and (B) a hindered phenol compound having a molecular weight of 250 to 2,000. Below, the components contained in this composition and the components optionally blended will be explained in detail.

<(A) component: Conjugated diene polymer>
The conjugated diene polymer that is component (A) (hereinafter also referred to as "(A) conjugated diene polymer") has a structural unit derived from a conjugated diene compound and a structural unit derived from an aromatic vinyl compound. It is a copolymer. (A) The conjugated diene polymer includes a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), a structural unit represented by the following formula (3), and a structural unit represented by the following formula ( When the composition ratios (molar ratios) of the structural units represented by 4) in the polymer are p, q, r, and s, respectively, the value α represented by the following formula (i) is 0.60 to 0. 98 highly saturated polymer.
α=(p+(0.5×r))/(p+q+(0.5×r)+s)
...(i)

(A) The molecular structure of the conjugated diene polymer is not particularly limited. (A) The conjugated diene polymer may be a linear polymer (hereinafter also referred to as "linear polymer") or a polymer having a multi-branched structure (hereinafter also referred to as "branched polymer"). or a mixture thereof. (A) Changes in the Mooney viscosity of the conjugated diene polymer due to differences in processing time (hereinafter also referred to as "resolution time") when removing the solvent from a polymer solution containing the conjugated diene polymer are small. (A) Conjugated diene polymer is a conjugated diene polymer with four or more branches, in that it is possible to obtain a crosslinked product with suppressed deterioration of physical properties (for example, deterioration of strength, viscoelastic properties, and abrasion resistance). It is preferable to include.

Part or all of the conjugated diene polymer (A) contained in the present composition contains a functional group (hereinafter referred to as "specific functional group") containing at least one element selected from the group consisting of nitrogen, oxygen, sulfur, and phosphorus. (also called "base").

In a polymer having a specific functional group (hereinafter also referred to as a "functional group-containing polymer"), the position of the specific functional group in the polymer is not particularly limited. Examples of the functional group-containing polymer include polymers having specific functional groups in the molecular chain (that is, between the ends of the molecular chain), at the ends of the molecular chain, or in both of these. When the functional group-containing polymer has a specific functional group at the end of the molecular chain, the functional group-containing polymer may have the specific functional group at the polymerization start end, or at the polymerization end end, and may have the specific functional group at the end of the polymerization end. It may be present at both the starting end and the polymerization ending end. Further, the functional group-containing polymer may have a specific functional group at a part of the terminal end in one polymer molecule, or may have a specific functional group at all the terminal ends in one polymer molecule. Functional group-containing polymers are particularly effective in improving the various physical properties (e.g., mechanical strength, abrasion resistance, viscoelastic properties, fuel efficiency, etc.) of the crosslinked product obtained using the present composition. It is preferable that the above terminal has a specific functional group.

Here, in this specification, the term "functional group" refers to a group having a specific structure within the molecule of an organic compound, and refers to an atomic group or bonding style that characterizes the compound. Specific functional groups possessed by the functional group-containing polymer include, for example, a primary amino group, a secondary amino group, a tertiary amino group, a nitrogen-containing group in which two hydrogen atoms of a primary amino group are protected, and a secondary amino group. A nitrogen-containing group in which one hydrogen atom of the group is protected, a tertiary amino group, an imino group, a pyridyl group, a phosphorus-containing group in which two hydrogen atoms of a primary phosphino group are protected, and a secondary phosphino group. A phosphorus-containing group in which one hydrogen atom is protected, a tertiary phosphino group, an epoxy group, a thioepoxy group, a hydroxyl group, an oxygen-containing group in which a hydrogen atom in a hydroxyl group is protected, a thiol group, a hydrogen atom in a thiol group is protected. Examples include a sulfur-containing group, a nitrogen-containing heterocyclic group (for example, a group having a heterocycle such as a pyridine ring and an imide ring), a hydrocarbyloxysilyl group, a hydrocarbyloxycarbonyl group, an ether bond, a thioether bond, and the like.

(A) The functional group-containing polymer contained in the conjugated diene polymer includes a conjugated diene polymer having an active end, a reaction point with the active end of the conjugated diene polymer, and a compound having a specific functional group. (hereinafter also referred to as "modified polymer") can be preferably used. In a compound (hereinafter also referred to as a "modifier") having a reactive site with the active end of the conjugated diene polymer and a specific functional group, the number of reactive sites with the active end may be one, or two or more. There may be. Specific examples of the specific functional group possessed by the modifier include the same groups and bonds as specific examples of the specific functional group possessed by the functional group-containing polymer. Such a modified polymer can be obtained by using, as a modifying agent, a coupling agent or a terminal modifying agent, which will be described later, and a compound having a specific functional group during production of the modified polymer. Here, the modified polymer may be a polymer obtained by further using, in addition to a coupling agent or a terminal modifying agent, a starting terminal modifying agent to be described later in the reaction for obtaining the modified polymer.

In addition, when the conjugated diene polymer (A) contains a functional group-containing polymer (preferably a modified polymer), the branched polymer and the functional group-containing polymer may be separate polymers with different molecular structures and physical properties. . Furthermore, since the branched polymer as the (A) conjugated diene polymer has a specific functional group, the conjugated diene polymer (A) may contain a branched polymer and also contain a functional group-containing polymer. . From the viewpoint of reducing the change in Mooney viscosity due to the difference in desolvation time and stabilizing the quality, it is preferable that the conjugated diene polymer (A) contains a branched polymer having a specific functional group, thereby stabilizing the quality. From the viewpoint of improving compound properties such as tensile strength while aiming at the above, it is more preferable to contain a branched polymer having a specific functional group at two or more terminals, and it is even more preferable to contain a branched polymer having a specific functional group at four or more terminals. preferable.

(A) The conjugated diene polymer is an aggregate of polymers having structural units derived from a conjugated diene compound. Specific embodiments of the conjugated diene polymer (A) include the following embodiments [a1] to [a4].
[a1] One or more polymers selected from the group consisting of a branched polymer with 4 or more branches (hereinafter also referred to as "first polymer"), a linear polymer, and a branched polymer with 3 or less branches (hereinafter referred to as "second polymer") polymer), and the first polymer and the second polymer are functional group-containing polymers.
[a2] An embodiment containing a first polymer and a second polymer, and of the first polymer and the second polymer, the first polymer is a functional group-containing polymer.
[a3] An embodiment containing a first polymer and a second polymer, and of the first polymer and the second polymer, the second polymer is a functional group-containing polymer.
[a4] An embodiment in which the second polymer is contained, the first polymer is not contained, and the second polymer is a functional group-containing polymer.
Among these, it is more preferable that at least the second polymer is contained, and the second polymer is a functional group-containing polymer, since the improvement effect of reducing the manufacturing process load and improving the compound properties is more preferable. and a second polymer, and the first polymer and the second polymer are functional group-containing polymers.

(A) The conjugated diene polymer can be produced by a method including the following polymerization step and hydrogenation step. The conjugated diene polymer (A) may also be produced by a method that includes at least one of the following reaction steps and modification steps in addition to the polymerization step and hydrogenation step. Hereinafter, while explaining the method for producing (A) the conjugated diene polymer, the molecular structure and the like of the (A) conjugated diene polymer will also be explained.

<Polymerization process>
The polymerization step is a step of polymerizing monomers containing a conjugated diene compound and an aromatic vinyl compound to obtain a conjugated diene polymer having an active terminal.

Conjugated diene compounds used in polymerization include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 1,3-heptadiene, 2- Examples include phenyl-1,3-butadiene, 3-methyl-1,3-pentadiene, and 2-chloro-1,3-butadiene. Among these, at least one selected from the group consisting of 1,3-butadiene, isoprene and 2,3-dimethyl-1,3-butadiene is preferred, and one or both of 1,3-butadiene and isoprene are more preferred. preferable. One type of conjugated diene compound may be used alone, or two or more types may be used.

Aromatic vinyl compounds used in 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, vinylxylene, vinyl Examples include naphthalene, vinylpyridine, diphenylethylene, and diphenylethylene containing a tertiary amino group (eg, 1-(4-N,N-dimethylaminophenyl)-1-phenylethylene). Among these aromatic vinyl compounds, one or both of styrene and α-methylstyrene are preferred. One type of aromatic vinyl compound may be used alone, or two or more types may be used.

(A) The proportion of structural units derived from an aromatic vinyl compound in the conjugated diene polymer is more than 0% by mass and 45% by mass or less with respect to the total structural units constituting the (A) conjugated diene polymer. It is preferable that By setting it as the said range, a crosslinked body with high strength and excellent wear resistance can be obtained while maintaining the processability of the polymer composition. The proportion of the structural units derived from the aromatic vinyl compound is more preferably 2% by mass or more, and preferably 5% by mass or more, based on the total structural units constituting the (A) conjugated diene polymer. More preferred. Further, the proportion of the structural units derived from the aromatic vinyl compound is more preferably 40% by mass or less, and more preferably 38% by mass or less, based on the total structural units constituting the (A) conjugated diene polymer. It is even more preferable that the amount is 35% by mass or less, and even more preferably 35% by mass or less. The content ratio of structural units derived from an aromatic vinyl compound in the polymer is a value measured by ¹ H-NMR.

The conjugated diene polymer (A) is preferably a copolymer containing 1,3-butadiene and styrene in its monomer composition, since it has high living properties in anionic polymerization.

From the viewpoint of improving various physical properties (e.g., mechanical strength, abrasion resistance, viscoelastic properties, etc.) of the crosslinked product obtained using the present composition, (A) the conjugated diene polymer contains a conjugated diene compound and an aromatic It is preferable to have a random copolymerization portion with irregular distribution with the group vinyl compound. (A) When the conjugated diene polymer is a random copolymer of a conjugated diene compound and an aromatic vinyl compound; It may further have a chain portion of a conjugated diene compound formed by additionally adding a conjugated diene compound after polymerization.

(A) The conjugated diene polymer may have a polymerization block portion containing an aromatic vinyl compound as a main component. (A) When the conjugated diene polymer has a polymerization block portion mainly composed of an aromatic vinyl compound, the contact area with equipment due to the flow of the polymer during drying of the (A) conjugated diene polymer This is preferable in that it is possible to suppress the increase, thereby suppressing the adhesion of the polymer to equipment.

(A) The position of the polymerization block portion containing an aromatic vinyl compound as a main component in the conjugated diene polymer is not particularly limited. (A) The conjugated diene polymer may have a polymerization block portion mainly composed of an aromatic vinyl compound at the end of the molecular chain, or within the molecular chain (between the ends). It's okay. (A) Conjugated diene polymers can simplify the production process of conjugated diene polymers while also suppressing the adhesion of polymers to equipment. It is preferable that the polymer block portion, which is the main component, is present at the end of the molecular chain.

It is preferable that the polymerization block portion containing an aromatic vinyl compound as a main component has structural units derived from the aromatic vinyl compound in an amount of 80% by mass or more, and preferably 85% by mass or more based on the total structural units constituting the polymerization block portion. It is more preferable that the content is 90% by mass or more.

(A) When the conjugated diene polymer has a polymerization block portion mainly composed of an aromatic vinyl compound, 35% of the total amount of structural units derived from the aromatic vinyl compound possessed by the (A) conjugated diene polymer % by mass or more may constitute the polymer block portion, and 40 mass % or more may constitute the polymer block portion. Furthermore, it is preferable that 80% by mass or more of the total amount of structural units derived from the conjugated diene compound contained in the conjugated diene polymer (A) constitutes a random copolymerization portion, and 90% by mass or more constitutes a random copolymerization portion. It is preferable that it constitutes a section.

(A) The monomers used in the polymerization reaction to obtain the conjugated diene polymer may contain compounds other than the conjugated diene compound and the aromatic vinyl compound (hereinafter also referred to as "other monomers"). good. Examples of other monomers include acrylonitrile, methyl (meth)acrylate, and ethyl (meth)acrylate. The proportion of other monomers used is preferably 10% by mass or less, more preferably 5% by mass or less, based on the total amount of monomers used for polymerization.

The polymerization method used may be any of a solution polymerization method, a gas phase polymerization method, and a bulk polymerization method. Among these, solution polymerization method is particularly preferred. Further, as the polymerization method, either a batch method or a continuous method may be used. When using a solution polymerization method, as an example of a specific polymerization method, a monomer containing a conjugated diene compound and an aromatic vinyl compound is mixed in an organic solvent with a polymerization initiator and a vinyl content used as necessary. Examples include a method of polymerizing in the presence of a regulator (hereinafter also referred to as "randomizer").

As the polymerization initiator, a metal compound containing an alkali metal or an alkaline earth metal can be used. Among these, compounds containing alkali metals are preferred. Specific examples of metal compounds include alkyllithiums such as methyllithium, ethyllithium, n-propyllithium, n-butyllithium, sec-butyllithium, and 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, ethoxy potassium, etc. can be mentioned. Among these, lithium compounds are preferred.

Furthermore, the metal compound used as a polymerization initiator may be a metal amide compound containing an alkali metal or an alkaline earth metal. (A) By performing polymerization to obtain a conjugated diene polymer in the presence of a metal amide compound, an amino group (preferably can introduce a secondary amino group or a tertiary amino group). The conjugated diene polymer (A) obtained by polymerizing monomers in the presence of a metal amide compound has the advantage that the strength of the crosslinked product can be increased, and that the crosslinked product has low fuel consumption when used in tires. This is preferable because it can enhance the effect of improving performance.

Among these, the metal amide compound is preferably a compound obtained by mixing a lithium compound (e.g., alkyl lithium, etc.) and a compound having a nitrogen atom (hereinafter also referred to as "initiating terminal modifier"). The starting terminal modifier is preferably a secondary amine compound. Specific examples include dimethylamine, diethylamine, dipropylamine, dibutylamine, dodecamethyleneimine, N,N'-dimethyl-N'-trimethylsilyl-1,6-diaminohexane, piperidine, pyrrolidine, hexamethyleneimine, heptamethyleneimine, Methyleneimine, dicyclohexylamine, N-methylbenzylamine, di-(2-ethylhexyl)amine, diallylamine, morpholine, N-(trimethylsilyl)piperazine, N-(tert-butyldimethylsilyl)-4-piperazine, 1,3- Examples include ditrimethylsilyl-1,3,5-triazinane.

In addition, when polymerizing in the presence of a metal amide compound, the metal amide compound is prepared by mixing the lithium compound and the starting terminal modifier in advance, and the prepared metal amide compound is added to the polymerization system to perform polymerization. You may do so. Alternatively, a metal amide compound may be prepared by adding a lithium compound and an initiating terminal modifier to the polymerization system and mixing the two in the polymerization system, followed by polymerization. During polymerization, the amount of the polymerization initiator used is preferably 0.01 to 20 mmol, more preferably 0.05 to 15 mmol, per 100 g of monomer used for polymer synthesis.

The randomizer can be used for the purpose of adjusting the vinyl bond content, which represents the content of vinyl bonds 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, potassium dodecylbenzenesulfonate, and the like. One type of randomizer can be used alone or two or more types can be used in combination.

As the organic solvent used in the polymerization, an organic solvent inert to the polymerization reaction can be preferably used. Specific examples of the organic solvent used in the polymerization include chain or cyclic aliphatic hydrocarbons, aromatic hydrocarbons, and the like. Among these, hydrocarbons having 3 to 8 carbon atoms are preferred, and specific examples include propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, cyclohexane, propene, and 1-butene. , isobutene, trans-2-butene, cis-2-butene, 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, one type can be used individually or two or more types can be used in combination.

In the case of solution polymerization, the monomer concentration in the reaction solvent is preferably 5 to 50% by mass, and 10 to 30% by mass, from the viewpoint of maintaining a balance between productivity and ease of polymerization control. is more preferable. The temperature of the polymerization reaction is preferably -20°C to 150°C, more preferably 0 to 120°C. Further, the polymerization reaction is preferably carried out under sufficient pressure to maintain the monomer substantially in a liquid phase. Such pressure can be obtained by pressurizing the inside of the reactor with a gas inert to the polymerization reaction. Through such a polymerization reaction, a conjugated diene polymer having an active terminal can be obtained.

In the conjugated diene polymer obtained by the above polymerization, the vinyl bond content in the structural unit derived from 1,3-butadiene is preferably 15 to 85 mol%. By setting the vinyl bond content to 15 mol % or more, flexibility is maintained in the resulting crosslinked product, and processability is improved. Additionally, it tends to have excellent wear resistance in low slip areas. The vinyl bond content is preferably 20 mol% or more, more preferably 25 mol% or more. Further, from the viewpoint of durability, the vinyl bond content of the conjugated diene polymer is preferably 75 mol% or less, more preferably 65 mol% or less. In this specification, "vinyl bond content" refers to the content of structural units having 1,2-bonds with respect to all structural units derived from 1,3-butadiene that the conjugated diene polymer before hydrogenation has. This is a value indicating a percentage. Vinyl bond content is determined by ¹ H-NMR equipment.

<Reaction process>
In the reaction step, the conjugated diene polymer obtained in the polymerization step is treated with a compound having four or more functional groups that can react with the active end of the conjugated diene polymer (hereinafter also referred to as a "coupling agent"). ) is reacted. By the reaction between the conjugated diene polymer having an active end and the coupling agent, four or more molecular chains of the conjugated diene polymer are bonded to one molecule of the coupling agent, thereby forming (A) the conjugated diene polymer. As a result of the coalescence, a polymer containing a branched polymer having four or more branches can be obtained.

As the coupling agent, a compound having at least one element (hereinafter also referred to as "specific element") selected from the group consisting of nitrogen, oxygen, sulfur, phosphorus, tin, and silicon can be preferably used. When a compound having a specific element is used as a coupling agent, it is preferable in that the strength of the resulting crosslinked product can be further increased.

Specific examples of such coupling agents include tetrachlorosilane, bis(trichlorosilyl)ethane, and the like. In addition, as a coupling agent, as a functional group having a specific element, a nitrogen-containing group formed by protecting two hydrogen atoms of a primary amino group, a nitrogen-containing group formed by protecting one hydrogen atom of a secondary amino group, etc. groups, tertiary amino groups, imino groups, nitrogen-containing heterocyclic groups (for example, groups having heterocycles such as pyridine rings and imide rings), hydroxyl groups, oxygen-containing groups in which the hydrogen atom of the hydroxyl group is protected, and thiol groups. A compound having a functional group (hereinafter also referred to as "functional group F1") such as a sulfur-containing group with a protected hydrogen atom or a hydrocarbyloxysilyl group can also be used.

Specific examples of the coupling agent having the functional group F1 include N,N,N',N'-tetra(3-trimethoxysilylpropyl)ethylenediamine, N,N,N',N'-tetra(3-trimethoxysilylpropyl), ethoxysilylpropyl)ethylenediamine, N,N,N'-tris(3-trimethoxysilylpropyl)-N'-methyl-ethylenediamine, N,N,N',N'-tetra(3-trimethoxysilylpropyl)- 1,3-propanediamine, N,N,N',N'-tetra(3-trimethoxysilylpropyl)-1,4-butanediamine, bis(3-trimethoxysilylpropyl)-[2-(dimethylamino) )ethyl]amine, bis(3-trimethoxysilylpropyl)-[2-(2,2-dimethoxy-1-aza-2-silacyclopentane)ethyl]amine, bis(3-triethoxysilylpropyl)-[ 2-(2,2-diethoxy-1-aza-2-silacyclopentane)ethyl]amine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-sila) cyclopentane)propyl]amine, bis(3-trimethoxysilylpropyl)-[2-(2,2-dimethoxy-1-aza-2-silacyclohexane)ethyl]amine, bis(3-trimethoxysilylpropyl)- [2-(2,2-dimethoxy-1-aza-2-silacyclooctane)ethyl]amine, N,N-bis(3-trimethoxysilylpropyl)-3-imidazolylpropylamine, bis(3-trimethoxy Silylpropyl)-(3-dimethylaminopropyl)amine, compounds represented by each of the following formulas (M-1) to (M-4), and the like.

(In formula (M-1), R ²⁰ represents a hydrogen atom or an alkyl group. n1 represents an integer from 1 to 8.)

When reacting a conjugated diene polymer having an active end with a coupling agent, by using a polymer obtained using a starting end modifier as the conjugated diene polymer having an active end, As the branched polymer having 4 or more branches, it is preferable to obtain a polymer having a nitrogen-containing functional group at the end. (A) By using a polymer composition containing a branched polymer having a nitrogen-containing functional group at the end and the number of branches of 4 or more as the conjugated diene polymer, the crosslinked product obtained from the polymer composition can be Strength and viscoelastic properties can be improved.

The reaction between the conjugated diene polymer having an active end and the coupling agent is preferably carried out as a solution reaction. The amount of the coupling agent used (the total amount when two or more types are used) is appropriately set so that the content ratio of the branched polymer with four or more branches in the conjugated diene polymer (A) is within the desired range. be able to. (A) In the production process of conjugated diene polymers (especially drying treatment), it suppresses the adhesion of polymer to equipment, thereby suppressing equipment contamination due to polymer retention and heat storage combustion of the accumulated polymer, and desolvation. From the viewpoint of stabilizing the quality by suppressing changes in Mooney viscosity due to differences in time, and from the viewpoint of obtaining a high-strength crosslinked product by stabilizing the quality of the polymer, the amount of the coupling agent to be used is determined by the amount of the polymerization initiator (i.e. It is preferably 0.01 mol or more, and more preferably 0.02 mol or more, per 1 mol of metal atoms involved in polymerization in the metal compound. In addition, the amount of the coupling agent to be used is determined from the viewpoint of adjusting the coupling rate to a desired value and obtaining a polymer composition that exhibits good processability and a crosslinked product with excellent viscoelastic properties. It is preferably 0.2 mol or less, more preferably 0.1 mol or less, per 1 mol of metal atoms involved in polymerization in the initiator. In addition, as a coupling agent, one type may be used individually, and two or more types may be used in combination.

In the coupling reaction, the reaction temperature is usually in the same range as the polymerization reaction. Specifically, the temperature is preferably -20°C to 150°C, more preferably 0 to 120°C. If the reaction temperature is low, the viscosity of the polymer after reaction tends to increase, and if 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.

By the above coupling reaction, it is possible to obtain the conjugated diene polymer (A) before hydrogenation, which contains a branched polymer having four or more branches. The conjugated diene polymer after the coupling reaction may contain a linear polymer. The linear polymer contained in the polymer solution after the coupling reaction is an unreacted polymer that did not react with the coupling agent among the linear polymers contained in the conjugated diene polymer having an active end.

<Modification process>
When the conjugated diene polymer obtained by the polymerization step or reaction step has a specific functional group, the polymer may be directly subjected to the next hydrogenation step. In addition, regarding the conjugated diene polymer obtained by the polymerization step or reaction step, whether or not there is a specific functional group, the active terminal of the conjugated diene polymer and the specific functional group are removed before the hydrogenation step. However, a treatment may be performed in which a compound capable of reacting with the active end of the conjugated diene polymer (excluding a coupling agent; hereinafter also referred to as "terminal modifier") is reacted. By performing such a treatment, when the conjugated diene polymer obtained in the polymerization step or reaction step contains a polymer having an active end, the molecular chain of the linear conjugated diene polymer is terminally modified. A polymer bonded to the agent (that is, having a specific functional group) can be included in the conjugated diene polymer (A). Note that the terminal modifier is a compound that differs from the coupling agent in that it has 1 to 3 reactive sites with the active end of the conjugated diene polymer.

A preferred specific example of the terminal modifier includes at least one selected from the group consisting of a compound represented by the following formula (5) and a compound represented by the following formula (6).

(In formula (5), A ¹¹ has at least one element selected from the group consisting of nitrogen, phosphorus, oxygen, and sulfur, has no active hydrogen, and has nitrogen and phosphorus with respect to R ³⁵ . , is a monovalent functional group bonded to oxygen, sulfur, or a carbon atom contained in a carbonyl group, or is a (thio)epoxy group. R ³³ and R ³⁴ are each independently a hydrocarbyl group .R ³⁵ is a hydrocarbylene group. t is an integer of 0 to 2. However, when t is 2, multiple R ^33s in the formula are the same or different. t is 0 or 1 In the case of , multiple R ^34s in the formula are the same or different.)

(In formula (6), A ¹² has at least one element selected from the group consisting of nitrogen, phosphorus, oxygen, and sulfur, has no active hydrogen, and has nitrogen and phosphorus with respect to R ³⁹ . , a monovalent functional group bonded with oxygen or sulfur, or a hydrocarbyl group having 1 to 20 carbon atoms. R ³⁶ and R ³⁷ are each independently a hydrocarbyl group. ^{R 38} is a hydrocarbyl group. It is a carbylene group. R ³⁹ is a single bond or a hydrocarbylene group. u is 0 or 1. However, when u is 0, multiple R ^37s in the formula are the same or different from each other. )

In the above formulas (5) and (6), regarding R ³³ , R ³⁴ , R ³⁶ , R ³⁷ and A ¹² when it is a hydrocarbyl group, the hydrocarbyl group is a linear or branched chain having 1 to 20 carbon atoms. An alkyl group having 3 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms is preferable.
The hydrocarbylene group represented by R ³⁸ and R ³⁹ is 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. is preferred. The hydrocarbylene group represented by R ³⁸ is preferably a linear or branched alkanediyl group having 1 to 20 carbon atoms.
t is preferably 0 or 1.

At least one element selected from the group consisting of nitrogen, phosphorus, oxygen, and sulfur, which A ¹¹ has when A ¹¹ is the monovalent functional group, and when A ¹² is the monovalent functional group, In some cases, at least one element selected from the group consisting of nitrogen, phosphorus, oxygen, and sulfur, which A ¹² has, may be protected with, for example, a trisubstituted hydrocarbylsilyl group. Note that in this specification, active hydrogen refers to a hydrogen atom bonded to an atom other than a carbon atom, and preferably refers to a hydrogen atom having a lower bond energy than a carbon-hydrogen bond of polymethylene. The term (thio)epoxy group includes epoxy groups and thioepoxy groups.

A ¹¹ may be a group that can become an onium ion with an onium salt forming agent. When the terminal modifier has such a group (A ¹¹ ), excellent shape retention can be imparted to the polymer. Specific examples of ^A11 include a nitrogen-containing group in which two hydrogen atoms of a primary amino group are protected, a nitrogen-containing group in which one hydrogen atom of a secondary amino group is protected, a tertiary amino group, and an imino group. pyridyl group, phosphorus-containing group in which two hydrogen atoms of a primary phosphino group are protected, phosphorus-containing group in which one hydrogen atom of a secondary phosphino group is protected, tertiary phosphino group, epoxy group, thioepoxy group, an oxygen-containing group formed by protecting the hydrogen atom of a hydroxyl group, a sulfur-containing group formed by protecting the hydrogen atom of a thiol group, and a hydrocarbyloxycarbonyl group. Among these, a group having a nitrogen atom is preferable because it has good affinity with silica, and a nitrogen-containing group in which two hydrogen atoms of a tertiary amino group or a primary amino group are protected is preferable. It is more preferable that Note that the protected group is a group in which A ¹¹ and A ¹² are converted into functional groups that are inert to the polymerization active terminal. The onium salt generating agent is a Bronsted acid or a compound that produces a Bronsted acid upon contact with water.

Specific examples of the terminal modifier include compounds represented by formula (5), such as N,N-bis(trimethylsilyl)aminopropyltrimethoxysilane, N,N-dimethylaminopropyltriethoxysilane, and N,N-dimethylaminopropyltriethoxysilane. -bis(trimethylsilyl)aminopropylmethyldiethoxysilane, N,N',N'-tris(trimethylsilyl)-N-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-(4-trimethylsilyl-1) -piperazino)propylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltriethoxysilane, and the like.

Specific examples of the compound represented by formula (6) include 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1,2-azacylorizine, 2,2-diethoxy-1-(3 -trimethoxysilylpropyl)-1,2-azacylorizine, 2,2-dimethoxy-1-phenyl-1,2-azacylorizine, 1-trimethylsilyl-2,2-dimethoxy-1-aza-2-silacyclopentane, 2 -(2,2-dimethoxy-1,2-azacylolidin-1-yl)-N,N-diethylethan-1-amine, 2-(2,2-dimethoxy-1,2-azacylolidin-1-yl)- Examples include N,N-dimethylethane-1-amine, 3-(2,2-dimethoxy-1,2-azacylolidin-1-yl)-N,N-diethylpropan-1-amine, and the like. As the terminal modifier, one type may be used alone, or two or more types may be used in combination.

The reaction between the conjugated diene polymer having an active terminal and the terminal modifier can be carried out, for example, as a solution reaction. This solution reaction may be carried out either batchwise or continuously. At this time, the method of adding the terminal modifier is not particularly limited, and examples thereof include a method of adding at once, a method of adding in portions, a method of adding continuously.

The amount of the terminal modifier to be used may be appropriately set depending on the type of compound used in the reaction, but it is preferably 0.05 mol per mol of metal atoms involved in the polymerization reaction that the polymerization initiator has. or more, and more preferably 0.1 mol or more. By using the terminal modifier in an amount of 0.1 molar equivalent or more, the modification reaction can proceed sufficiently, and the effect of improving the dispersibility of the inorganic filler can be enhanced. Further, the amount of the terminal modifier is preferably 1.0 mol or less, more preferably 0.8 mol or less, per 1 mol of the metal atom of the polymerization initiator that participates in the polymerization reaction.

In the modification reaction using a terminal modifier, the reaction temperature is usually the same as the temperature of the polymerization reaction, preferably -20 to 150°C, more preferably 0 to 120°C, and 20 to 100°C. It is even more preferable that there be. When the temperature of the modification reaction is low, the viscosity of the polymer solution tends to increase. In addition, if the temperature of the modification reaction is high, the polymerization active terminal is likely to be deactivated. The reaction time for terminal modification is preferably 1 minute to 5 hours, more preferably 2 minutes to 1 hour.

(A) The coupling rate of the conjugated diene polymer is determined by the proportion of the branched polymer present in the (A) conjugated diene polymer, the molecular weight of the conjugated diene polymer having an active end, and the coupling agent used. It can be set depending on the number of functional groups, etc. (A) From the viewpoint of suppressing changes in Mooney viscosity due to differences in desolution time of the conjugated diene polymer and stabilizing the quality, the coupling rate of the (A) conjugated diene polymer is preferably 10% or more, It is more preferably 15% or more, and even more preferably 20% or more. In addition, the coupling rate of the conjugated diene polymer (A) is preferably 70% or less, from the viewpoint of obtaining a polymer composition with good processability and the viewpoint of obtaining a crosslinked product with excellent viscoelastic properties, and 60% or less. % or less, more preferably 50% or less.

In addition, in this specification, "coupling rate" refers to the linear conjugated diene polymer having an active end used in the reaction of a linear conjugated diene polymer having an active end with a modifier. It refers to the proportion (% by mass) of the linear conjugated diene polymer used in the reaction among the diene polymers. Specifically, the amount of coupling agent Alternatively, it represents the proportion (% by mass) of a polymer in which two or more molecular chains of linear conjugated diene polymers are bonded via a terminal modifier. The coupling rate is calculated by separating the waveform of a molecule in which two or more linear conjugated diene polymer chains are bonded together from a GPC curve obtained using gel permeation chromatography (GPC). , can be calculated from the peak area ratio.

In addition, if neither the reaction step nor the modification step is performed on the conjugated diene polymer having an active end obtained in the polymerization step, the conjugated diene polymer having an active end and the polymerization termination using alcohol etc. After reacting with the agent, the next hydrogenation step may be performed. In this case, it is preferable to use a starting terminal modifier in the polymerization step to obtain a conjugated diene polymer having a specific functional group.

<Hydrogenation process>
In the hydrogenation step, the conjugated diene polymer obtained by the above polymerization step, reaction step, or modification step is hydrogenated (hereinafter also referred to as "hydrogenation"). Any method and conditions for the hydrogenation reaction can be used as long as a conjugated diene polymer having a desired hydrogenation rate can be obtained. Examples of such hydrogenation methods include methods using catalysts mainly composed of organometallic compounds of titanium; catalysts consisting of organometallic compounds of iron, nickel, and cobalt and organometallic compounds such as alkyl aluminum; 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. Examples include methods. Among the various methods, a homogeneous catalyst consisting of an organometallic compound of titanium alone or an organometallic compound of titanium and an organometallic compound of lithium, magnesium, or aluminum (for example, Japanese Patent Publication No. 4841/1986, Japanese Patent Publication No. The method of hydrogenating under mild conditions at low pressure and low temperature using the catalyst described in Japanese Patent Publication No. 37970 is industrially preferable, and is also suitable because of its high hydrogenation selectivity to the double bond of butadiene.

The hydrogenation of the conjugated diene polymer is preferably carried out using a solvent that is inert to the catalyst and in which the conjugated diene polymer is soluble. Preferred solvents include chain aliphatic hydrocarbons such as n-pentane, n-hexane, and n-octane; cyclic aliphatic hydrocarbons such as cyclohexane and cycloheptane; aromatic hydrocarbons such as benzene and toluene; and diethyl ether. and ethers such as tetrahydrofuran. The solvent used for hydrogenation may be one of the above compounds, or a mixture containing them as main components.

The hydrogenation reaction is generally carried out by holding a conjugated diene polymer at a predetermined temperature under hydrogen or an inert atmosphere, adding a hydrogenation catalyst with or without stirring, and then introducing hydrogen gas to a predetermined temperature. It is carried out by applying pressure. The inert atmosphere means an atmosphere that does not react with substances involved in the hydrogenation reaction, and includes, for example, helium, neon, argon, and the like. Air and oxygen are not preferred because they oxidize the catalyst and cause deactivation of the catalyst. Further, nitrogen is not preferable because it acts as a catalyst poison during the hydrogenation reaction and reduces hydrogenation activity. In particular, it is most preferable that the inside of the hydrogenation reactor be in an atmosphere containing only hydrogen gas.

The hydrogenation reaction process can be a batch process, a continuous process, or a combination thereof. Further, when a titanocene diaryl compound is used as a hydrogenation catalyst, it may be added alone to the reaction solution as it is, or may be added as a solution in an inert organic solvent. As the inert organic solvent used when the catalyst is used as a solution, various solvents that do not react with substances involved in the hydrogenation reaction can be used. Preferably, it is the same solvent as used in the hydrogenation reaction. Further, the preferable amount of the catalyst added is 0.02 to 20 mmol per 100 g of the conjugated diene polymer before hydrogenation.

(A) The conjugated diene polymer includes a structural unit represented by the above formula (1), a structural unit represented by the formula (2), a structural unit represented by the formula (3), and a structural unit represented by the formula (4). When the composition ratio (molar ratio) of the structural units represented by in the polymer is p, q, r, and s, respectively, the value α represented by formula (i) is 0.60 or more and 0.98 or less. be.
α=(p+(0.5×r))/(p+q+(0.5×r)+s)
...(i)

If the value α of the (A) conjugated diene polymer is less than 0.60, the amount of unsaturated bonds in the (A) conjugated diene polymer is large, so the change in Mooney viscosity due to the difference in dissolution time becomes large. There is a tendency that the quality of the conjugated diene polymer (A) becomes unstable or that the heat storage and combustibility of the conjugated diene polymer (A) attached to the equipment increases. Furthermore, there is a concern that the strength and viscoelastic properties of the crosslinked product may deteriorate due to the destabilization of the quality of the conjugated diene polymer (A). (A) When the value α of the conjugated diene polymer exceeds 0.98, crosslinking cannot proceed sufficiently, and the strength of the crosslinked product tends to decrease and the viscoelastic properties tend to decrease. It tends to be difficult to secure adhesiveness in a laminated crosslinked product that is laminated with other conjugated diene material sheets and vulcanized. From such a viewpoint, the value α of the conjugated diene polymer (A) is more preferably 0.65 or more, still more preferably 0.70 or more, and even more preferably 0.75 or more. Further, the value α of the conjugated diene polymer (A) is more preferably 0.97 or less, even more preferably 0.95 or less, and even more preferably 0.92 or less.

Note that the value α represented by formula (i) corresponds to the hydrogenation rate of the conjugated diene polymer. For example, when α is 0.60, the hydrogenation rate of the conjugated diene polymer is 60%. The hydrogenation rate and value α of the conjugated diene polymer can be adjusted by adjusting the hydrogenation reaction time or controlling the cumulative supply amount of hydrogen. In this specification, the hydrogenation rate is a value measured using a ¹ H-NMR device. Regarding p, q, r, and s in formula (i), for example, when the composition ratio of each structural unit of the above formulas (1) to (4) in the polymer is expressed in mol%, p, q, r and s can each take a value of 0 to 100% (however, the total value of p, q, r, and s is 100% or less).

(A) A preferred method for obtaining the conjugated diene polymer is to solution polymerize monomers containing 1,3-butadiene and styrene in the presence of a polymerization initiator (preferably a metal amide compound), and to obtain the resulting polymer. After a coupling agent is added to the combined solution and a coupling reaction is performed, a terminal modifier is preferably added, and then a hydrogenation step is performed. This method is preferred in that a crosslinked product having excellent various physical properties (strength, abrasion resistance, viscoelastic properties, vulcanization adhesiveness, etc.) can be obtained, and is also industrially useful.

(A) The weight average molecular weight (Mw) of the conjugated diene polymer measured using gel permeation chromatography (GPC) in terms of polystyrene indicates that the crosslinked product has high strength and excellent wear resistance. From the viewpoint of yield, it is preferably 1.5×10 ⁵ to 2.0×10 ⁶ . The Mw of the conjugated diene polymer is more preferably 1.8×10 ⁵ or more, and still more preferably 2.0×10 ⁵ or more. Moreover, Mw is more preferably 1.6×10 ⁶ or less, still more preferably 1.4×10 ⁶ or less. The weight average molecular weight of the conjugated diene polymer referred to herein is a value determined from all peaks of a GPC curve measured by GPC before hydrogenation. In the following, it is also referred to as "total average molecular weight."

For (A) conjugated diene polymer, the molecular weight distribution (ratio of weight average molecular weight (Mw) to number average molecular weight (Mn)) of the total amount of polymer (i.e., aggregate of different molecular weights) measured by GPC ( Weight average molecular weight/number average molecular weight) is preferably 1.1 or more and 4.0 or less. A molecular weight distribution of 1.1 or more is preferable in terms of excellent processability, and a molecular weight distribution of 4.0 or less is preferable in that low hysteresis loss properties of the resulting crosslinked product can be sufficiently improved. (A) The molecular weight distribution of the conjugated diene polymer is more preferably 1.2 or more. Further, the molecular weight distribution of the conjugated diene polymer (A) is more preferably 3.5 or less, still more preferably 3.0 or less.

(A) For the conjugated diene polymer, the peak top molecular weight of the peak with the smallest molecular weight (hereinafter also referred to as "1st peak molecular weight") measured by GPC is preferably 0.8 x 10 ⁵ to 1.0 The range is ×10 ⁶ . When the 1st peak molecular weight is 0.8×10 ⁵ or more, the strength and abrasion resistance of the resulting crosslinked product can be sufficiently increased, while the viscoelastic properties and processability can be improved. The 1st peak molecular weight is more preferably 0.9×10 ⁵ or more, and even more preferably 1.0×10 ⁵ or more. Moreover, from the viewpoint of improving viscoelastic properties and processability, the 1st peak molecular weight is more preferably 8.0×10 ⁵ or less, and even more preferably 5.0×10 ⁵ or less. Note that the 1st peak molecular weight is a value determined from a GPC curve measured by GPC before hydrogenation.

(A) The conjugated diene polymer preferably contains one or more polymers (second polymer) selected from the group consisting of a linear polymer and a branched polymer having three or less branches, together with a four-branched or more branched polymer. . More specifically, the second polymer is a hydrogenated product of the conjugated diene polymer obtained by the above polymerization step, or a conjugated diene polymer obtained by the reaction step and reacted with the coupling agent. It is a hydrogenated product of a polymer that did not. From the viewpoint of increasing the strength of the crosslinked product, the second polymer preferably has a specific functional group at some or all of the end portions, and more preferably has a specific functional group at all of the end portions. For example, a linear polymer modified at both ends can be obtained by using a metal amide compound as a polymerization initiator in the polymerization step and performing the above modification step.

The proportion of the branched polymer having four or more branches in the conjugated diene polymer (A) is preferably 10% by mass or more based on the total amount (100% by mass) of the conjugated diene polymer (A). (A) By setting the proportion of the branched polymer having four or more branches in the conjugated diene polymer to be within the above range, changes in Mooney viscosity due to differences in the desolvation time of the (A) conjugated diene polymer can be suppressed, and quality can be improved. This is preferable in that it can achieve stabilization. (A) The proportion of the branched polymer having four or more branches in the conjugated diene polymer is more preferably 15% by mass or more, and even more preferably 20% by mass or more. Further, the proportion of the branched polymer having four or more branches in the conjugated diene polymer (A) is preferably 70% by mass or less from the viewpoint of improving the processability of the polymer composition and the viscoelastic properties of the crosslinked product, The content is more preferably 60% by mass or less, and even more preferably 50% by mass or less. (A) The proportion (mass%) of branched polymers with 4 or more branches in the conjugated diene polymer is determined from the GPC curve obtained using GPC. It can be calculated by separating the waveform of the coupled molecules (coupling polymer) into components.

The proportion of the modified polymer in the (A) conjugated diene polymer is preferably 60% by mass or more based on the total amount of the (A) conjugated diene polymer. (A) When the proportion of the modified polymer in the conjugated diene polymer is within the above range, the resulting crosslinked product can have good strength, abrasion resistance, viscoelastic properties, and fuel efficiency. (A) The proportion of the modified polymer in the conjugated diene polymer is more preferably 70% by mass or more, and even more preferably 80% by mass or more. The proportion (mass%) of the modified polymer in the conjugated diene polymer (A) was calculated by adding the proportion of the linear polymer having a partial structure derived from the terminal modifier and the coupling rate. It is a value. The reaction rate of the terminal modifier in the reaction between the conjugated diene polymer having an active terminal and the terminal modifier is determined by gas chromatography measurement of the polymer solution after the modification reaction with the terminal modifier. It can be calculated by quantifying the amount.

(A) The conjugated diene polymer preferably has a nitrogen content of 50 ppm or more based on the total amount of the (A) conjugated diene polymer. (A) When the proportion of nitrogen in the conjugated diene polymer is within the above range, a crosslinked product with excellent properties such as strength, viscoelasticity, and abrasion resistance can be obtained while sufficiently reducing the load on the manufacturing process. It is preferable in that it can be obtained. From this point of view, the proportion of nitrogen in the (A) conjugated diene polymer is more preferably 60 ppm or more, and more preferably 80 ppm or more, based on the total amount of the (A) conjugated diene polymer. preferable. The proportion of nitrogen in the (A) conjugated diene polymer is preferably 500 ppm or less, more preferably 450 ppm or less, based on the total amount of the (A) conjugated diene polymer. The nitrogen content of the polymer is a value measured in accordance with the chemiluminescence method of JIS K2609:1998 (Crude oil and petroleum products - Nitrogen content test method). The details of the measurement method follow the method described in Examples described later.

The conjugated diene polymer (A) having nitrogen can be produced by using a nitrogen-containing compound (preferably a secondary amine compound) as an initiating terminal modifier, or by using a nitrogen-containing monomer. It can be obtained by employing a method of polymerization using a nitrogen-containing compound, a method of using a nitrogen-containing compound as a terminal modifier, a method of using a nitrogen-containing compound as a coupling agent, or a combination of two or more of these methods. .

<(B) component: hindered phenol compound>
The present composition contains a hindered phenol compound (hereinafter also referred to as "compound (B)") with a molecular weight of 250 to 2,000. Here, in this specification, the term "hindered phenol compound" refers to carbons on both sides of the carbon to which the hydroxyl group is bonded (i.e., to the carbons constituting the aromatic ring (preferably benzene ring) to which the hydroxyl group is bonded). A compound having a partial structure (hereinafter also referred to as a "hindered phenol structure") in which groups each having one or more carbon atoms are bonded to two ortho positions.

In the hindered phenol structure, a group having one or more carbon atoms (hereinafter also referred to as "specific group Good, but not particularly limited. Examples of the specific group Xb include a saturated or unsaturated chain hydrocarbon group having 1 to 40 carbon atoms, a saturated or unsaturated alicyclic hydrocarbon group having 3 to 40 carbon atoms, and an aromatic group having 6 to 40 carbon atoms. group hydrocarbon groups, and groups in which one or more of the methylene groups and hydrogen atoms in these hydrocarbon groups are replaced with a functional group (e.g., hydroxyl group, (meth)acryloyl group, -O-, -S-, etc.) can be mentioned. (A) In the process of manufacturing conjugated diene polymers (particularly in the drying process of polymers), it suppresses the thermal accumulation and combustion of polymers that adhere to equipment and remain, and also suppresses changes in Mooney viscosity due to variations in desolvation time. From the viewpoint of stabilizing the quality and obtaining a crosslinked product exhibiting good properties, at least one of the two specific groups Xb in the hindered phenol structure preferably has 2 or more carbon atoms, and 4 or more carbon atoms. It is more preferable that there be.

It is preferable that at least one of the two specific groups Xb in the hindered phenol structure of the compound (B) is bonded to the carbon constituting the aromatic ring through a tertiary carbon. That is, in the compound (B), carbon is bonded to at least one of the carbons on both sides of the carbon in the aromatic ring to which the hydroxyl group is bonded, and the carbon is preferably a quaternary carbon.

Such hindered phenol compounds include N-octadecyl-3-(4'-hydroxy-3',5'-di-t-butylphenyl)propionate, tetrakis{methylene-3-(3',5'- di-t-butyl-4-hydroxyphenyl)propionate}methane, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, distearyl(4-hydroxy-3-methyl) -5-t-butylbenzyl)malonate, triethylene glycol-bis{3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate}, 1,6-hexanediol-bis{3-(3 ,5-di-t-butyl-4-hydroxyphenyl)propionate}, 2,4-bis-(N-octylthio)-6-(4-hydroxyphenyl ``3,5-di-t-butyl-anilino-1 , 3,5-triazine, 2,2-thiodiethylenebis{3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate}, 2,2-thiobis(4-methyl-6-t- butylphenol), 2,2'-methylenebis-(4-ethyl-6-t-butylphenol), N,N'-hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propane amide], 3,5-di-t-butyl-4-hydroxybenzylphosphonate diethyl ester, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4 -hydroxybenzyl)benzene, bis(3,5-di-t-butyl-4-hydroxybenzyl) sulfide, tris(3,5-di-t-butyl-4-hydroxybenzyl)-isocyanurate, 2,4- Bis{(octylthio)methyl}-O-cresol, isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, N,N'-bis{3-(3,5-di- Examples include t-butyl-4-hydroxyphenyl)propionylhydrazine and (meth)acrylate compounds having a hindered phenol structure.

Examples of the (meth)acrylate compound having a hindered phenol structure include a compound represented by the following formula (7).

(In formula (7), R ¹ to R ⁵ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. ^{R 6} is a hydrogen atom or a methyl group.)

In formula (7), the alkyl group having 1 to 10 carbon atoms represented by R ¹ to R ⁵ includes methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, Examples include isobutyl group, tert-butyl group, and 1,1-dimethylpropyl group. Among these, R ¹ and R ² are sterically hindered, such as isopropyl group, sec-butyl group, tert-butyl group, and 1,1-dimethylpropyl group, in terms of high stabilizing effect and ease of production. Large bulky alkyl groups are preferred. R ³ and R ⁴ are preferably a tert-butyl group or a 1,1-dimethylpropyl group from the viewpoint of suppressing the reaction that produces a quinoid structure accompanied by hydrogen abstraction. R ⁵ is preferably a methyl group, ethyl group, n-propyl group or n-butyl group.

As a compound (B), it can be highly effective in suppressing equipment contamination caused by volatile matter and bleed substances during the drying process of polymers, and can stabilize quality by suppressing changes in Mooney viscosity due to variations in desolvation time, (A) It is highly effective in reducing the process load in the process of manufacturing conjugated diene polymers, and various properties such as the strength, abrasion resistance, viscoelastic properties of the crosslinked product, and low fuel consumption performance when used in tires Among them, hindered phenol compounds having an unsaturated group can be preferably used in that they can enhance the improvement effect. When the compound (B) has an unsaturated group, examples of the unsaturated group include a vinyl group, a (meth)acryloyl group, and a vinylphenyl group. Among these, the hindered phenol compound having an unsaturated group as component (B) preferably has a (meth)acryloyl group, and the compound represented by formula (7) is more preferable. Among these, in formula (7), R ¹ and R ² are tert-butyl groups, R ³ and R ⁴ are methyl groups, R ⁵ and R ⁶ are hydrogen atoms, and R ¹ to R ⁴ are tert-pentyl groups. A compound in which R ⁵ is a methyl group and R ⁶ is a hydrogen atom is preferred.

The molecular weight of the compound (B) is 250 to 2,000. If the molecular weight of the hindered phenol compound added to the present composition is less than 250, the hindered phenol compound will easily migrate to the mixed solvent phase during the desolvation process, and the amount remaining in the polymer will tend to decrease. There is a concern that thermal storage combustion and volatilization of polymer components adhering to equipment during the drying process of the polymer cannot be sufficiently suppressed. Therefore, it is necessary to frequently perform treatment to remove components attached to the equipment, which increases the process load. Furthermore, if the molecular weight of the hindered phenol compound exceeds 2,000, there is a concern that the compatibility with the conjugated diene polymer (A) will decrease, leading to a decrease in performance. From such a viewpoint, the molecular weight of the compound (B) is preferably 300 or more, more preferably 350 or more. Moreover, the molecular weight of the compound (B) is preferably 1,800 or less, more preferably 1,500 or less, and even more preferably 1,200 or less.

The compounding amount of (B) compound (the total amount when two or more types are used) is 0.1 parts by mass or more and 2.2 parts by mass or less with respect to 100 parts by mass of (A) conjugated diene polymer. It is preferable that there be. (B) By setting the blending amount of the compound to 0.1 part by mass or more, the change in Mooney viscosity due to the difference in desolvation time can be made smaller. (A) It is possible to reduce the heat storage and combustibility of the conjugated diene polymer, and to enhance the effect of improving various properties such as the strength and viscoelastic properties of the crosslinked product, and fuel efficiency when used in tires. From this point of view, the blending amount of the compound (B) is more preferably 0.2 parts by mass or more, and more preferably 0.4 parts by mass or more with respect to 100 parts by mass of the conjugated diene polymer (A). It is even more preferable that there be. Furthermore, by setting the blending amount of the compound (B) to 2.2 parts by mass or less, it is possible to increase the effect of suppressing equipment contamination caused by volatile components and bleed products during the drying treatment of the polymer, and to use the present composition. There is a tendency that it is possible to suppress a decrease in the strength of the crosslinked product obtained by the above process and a decrease in fuel efficiency when used in tires. (B) The compounding amount of the compound is more preferably 1.8 parts by mass or less, even more preferably 1.4 parts by mass or less, and 1.0 parts by mass or less, based on 100 parts by mass of the (A) conjugated diene polymer. It is even more preferable that the amount is not more than parts by mass. In addition, as the (B) compound, one type may be used alone, or two or more types may be used in combination.

<Other ingredients>
In addition to (A) the conjugated diene polymer and (B) the compound, the composition may further contain the following components.

・Component (C): Specific stabilizer This composition contains at least one type selected from the group consisting of phosphorus stabilizers and organic sulfur stabilizers as component (C), and has a molecular weight of 250 to 2,000. It may further contain a compound (hereinafter also referred to as "(C) specific stabilizer"). By containing the specific stabilizer (C) together with the compound (B), this composition has the effect of reducing the change in Mooney viscosity with respect to desolution time and achieving quality stability with a smaller amount of additive, and ( A) During the drying process of the conjugated diene polymer, it is possible to obtain the effect of suppressing heat storage combustion and component volatilization due to the adhesion of the conjugated diene polymer (A) to the equipment. This makes it possible to improve equipment contamination and the performance of the crosslinked product in a well-balanced manner.

(C) As the specific stabilizer, compounds known as phosphorus antioxidants and organic sulfur antioxidants and having a molecular weight within the range of 250 to 2,000 can be used. Specific examples of these include tris(2,4-di-t-butylphenyl) phosphite and tetrakis(2,4-di-t-butylphenyl) as phosphorus stabilizers with a molecular weight of 250 to 2,000. -4-,4'-bisphenylene phosphite, tris(nonylphenyl) phosphite, distearylpentaerythol diphosphite, bis(2,4,di-t-butylphenyl)pentaerythol phosphite, bis( 2,6,di-t-butyl-4-methylphenyl)pentaerythol phosphite, 2,2-methylenebis(4,6-di-t-butylphenyl)octylphosphite, tetrakis(2,4-di- (t-butylphenyl) 4,4'-bisphenylene-di-phosphite and the like. As the phosphorus stabilizer, one kind can be used alone or two or more kinds can be used in combination.

Specific examples of organic sulfur stabilizers with a molecular weight of 250 to 2,000 include didodecylthiodipropionate, ditetradecylthiodipropionate, dioctadecylthiodipropionate, and bis[3-(dodecylthio)propionic acid]. 2,2-bis[[3-(dodecylthio)-1-oxopropyloxy]methyl]-1,3-propanediyl, pentaerythritol tetrakis (3-dodecylthiopropionate), thiobis(N-phenyl-β- Examples include organic thio acid compounds such as naphthylamine). As the organic sulfur stabilizer, one type can be used alone or two or more types can be used in combination.

(C) The blending amount of the specific stabilizer (if two or more types are used, the total amount) is 0.01 parts by mass or more and 2.0 parts by mass with respect to 100 parts by mass of (A) conjugated diene polymer. The following is preferable. The blending amount of the specific stabilizer (C) is more preferably 0.02 parts by mass or more, and even more preferably 0.05 parts by mass or more, based on 100 parts by mass of the conjugated diene polymer (A). Moreover, the blending amount of the specific stabilizer (C) is more preferably 1.5 parts by mass or less, and even more preferably 1.2 parts by mass or less, based on 100 parts by mass of the (A) conjugated diene polymer. (C) By setting the blending amount of the specific stabilizer within the above range, it is possible to reduce the change in Mooney viscosity due to variations in desolvation time, and to reduce the adhesion of (A) conjugated diene polymer to equipment during drying. The effect of suppressing thermal storage combustion and volatilization of components can be obtained while reducing the amount of the additive of the (B) compound. As the specific stabilizer (C), only a phosphorus stabilizer, only an organic sulfur stabilizer, or a combination of a phosphorus stabilizer and an organic sulfur stabilizer may be used. It's okay.

- (D) Component: Inorganic filler This composition may contain an inorganic filler. Examples of the inorganic filler include silica and carbon black, and fillers other than silica and carbon black (hereinafter also referred to as "other fillers"). The inorganic filler blended into the present composition preferably contains one or both of silica and carbon black.

- (D-1) Component: Silica The present composition can contain silica. The amount of silica blended is preferably in the range of 20 to 120 parts by weight, more preferably in the range of 30 to 100 parts by weight, based on 100 parts by weight of the rubber component containing the conjugated diene polymer (A). When the blending amount of silica is 20 parts by mass or more based on 100 parts by mass of the rubber component, the low hysteresis loss property, fracture characteristics, and abrasion resistance of the polymer composition can be sufficiently improved; When the amount is less than 1.9 parts, the processability of the polymer composition can be sufficiently improved.

In this specification, the "rubber component" contained in the polymer composition refers to a polymer that can be cured to exhibit rubber elasticity by heat curing or the like. The cured product exhibits the property of causing large deformation (for example, deformation that stretches more than twice as much when stretched at room temperature) with a small force at room temperature, and rapidly returning to almost its original shape when the force is removed.

Silica is not particularly limited, and examples thereof include wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate, and the like. Among these, wet silica is preferred. As silica, one type may be used alone, or two or more types may be used in combination. Furthermore, the BET specific surface area of silica (value measured according to ISO 5794/1) is preferably in the range of 40 to 350 m ² /g, more preferably in the range of 80 to 350 m ² /g, and more preferably in the range of 120 to 350 m ² A range of /g is particularly preferred. Silica having a BET specific surface area within this range has the advantage of being able to achieve both rubber reinforcing properties and dispersibility in the (A) modified diene polymer. Examples of such silica include Tosoh Silica Co., Ltd., trade name "Nipsil AQ" (BET specific surface area = 205 m ² /g), "Nipsil KQ", Degussa Corporation, trade name "Ultrasil VN3" (BET specific surface area = 205 m 2 /g), = 175 m ² /g) and the like can be used.

Two or more types of silica having different specific surface areas may be used in combination in the present composition. Specifically, the first silica has a CTAB (cetyltrimethylammonium bromide) specific surface area of 180 m ² /g or more, a BET specific surface area of 185 m ² /g or more, and an aggregate size of 45 nm or more, and a CTAB specific surface area of 95 m ² /g or less, and a second silica having a BET specific surface area of 100 m ² /g or less may be used in combination. Note that the CTAB specific surface area of silica is measured in accordance with ASTM D3765-92.

The present composition comprises a first silica having a CTAB specific surface area of 180 m ² /g or more, a BET specific surface area of 185 ^m ² /g or more, and an aggregate size of 45 nm or more; The second silica may have a surface area of 100 m ² /g or less. By using such a first silica and a second silica in combination, it becomes possible to favorably disperse the first silica, which has a small average primary particle diameter but a relatively large aggregate size, in the rubber component. This improves the dispersibility of silica and provides excellent fracture strength, wear resistance, fuel efficiency, and processability.

The CTAB specific surface area of the first silica is preferably 190 m ² /g or more, more preferably 195 m ² /g or more, even more preferably 197 m ² /g or more. When the CTAB specific surface area is less than 180 m ² /g, it tends to be difficult to sufficiently improve fracture strength and wear resistance. The CTAB specific surface area of the first silica is preferably 350 m ² /g or less, more preferably 300 m ² /g or less, even more preferably 250 m ² /g or less. When the CTAB specific surface area exceeds 350 m ² /g, the dispersibility is poor and agglomeration tends to occur easily, so that physical properties tend to deteriorate.

The BET specific surface area of the first silica is preferably 190 m ² /g or more, more preferably 195 m ² /g or more, and still more preferably 210 m ² /g or more. When the BET specific surface area is less than 185 m ² /g, it tends to be difficult to sufficiently improve fracture strength and wear resistance. The BET specific surface area is preferably 350 m ² /g or less, more preferably 300 m ² /g or less, even more preferably 260 m ² /g or less. When the BET specific surface area exceeds 350 m ² /g, the dispersibility is poor and agglomeration tends to occur easily, so that physical properties tend to deteriorate. Note that the BET specific surface area of silica is measured according to ASTM D3037-81.

The aggregate size of the first silica is 45 nm or more, preferably 50 nm or more, more preferably 55 nm or more, and still more preferably 60 nm or more. Further, the aggregate size is preferably 100 nm or less, more preferably 80 nm or less, still more preferably 70 nm or less, particularly preferably 67 nm or less. By having such an aggregate size, it is possible to provide excellent fuel efficiency and wear resistance while having good dispersibility (processability). Note that the aggregate size of silica can be measured by the method described in JP-A-2011-140613.

The average primary particle diameter of the first silica is preferably 25 nm or less, more preferably 22 nm or less, even more preferably 17 nm or less, particularly preferably 14 nm or less. The lower limit of the average primary particle diameter is not particularly limited, but is preferably 3 nm or more, more preferably 5 nm or more, and still more preferably 7 nm or more. Although it has such a small average primary particle diameter, the carbon black-like structure with the above-mentioned aggregate size can further improve the dispersibility (processability) of silica, resulting in low fuel consumption and wear resistance. can be further improved. The average primary particle size of silica can be determined by observing silica using a transmission or scanning electron microscope, measuring the particle size of 400 or more silica primary particles observed within the field of view, and averaging the particle size. .

The CTAB specific surface area of the second silica is preferably 10 m ² /g or more, more preferably 20 m ² /g or more, even more preferably 30 m ² /g or more. If the CTAB specific surface area is less than 10 m ² /g, the reinforcing properties will be low, and it may be difficult to sufficiently ensure the mechanical strength and abrasion resistance required for a polymer composition for tire manufacturing. The CTAB specific surface area is preferably 80 m ² /g or less, more preferably 60 m ² /g or less, even more preferably 50 m ² /g or less. If the CTAB specific surface area exceeds 95 m ² /g, the dispersibility of silica may deteriorate, making it difficult to improve fracture strength and abrasion resistance.

The BET specific surface area of the second silica is preferably 10 m ² /g or more, more preferably 20 m ² /g or more, even more preferably 30 m ² /g or more. If the BET specific surface area is less than 10 m ² /g, the reinforcing properties will be low, and it may be difficult to ensure the mechanical strength and abrasion resistance required for a polymer composition for tire manufacturing. The BET specific surface area is preferably 85 m ² /g or less, more preferably 60 m ² /g or less, even more preferably 50 m ² /g or less. If the BET specific surface area exceeds 100 m ² /g, the dispersibility of silica may deteriorate, making it difficult to improve fracture strength and abrasion resistance.

The average primary particle diameter of the second silica is preferably 20 nm or more, more preferably 25 nm or more, even more preferably 30 nm or more, particularly preferably 35 nm or more, and most preferably 55 nm or more. Further, the upper limit of the average primary particle diameter is not particularly limited, but is preferably 500 nm or less, more preferably 200 nm or less, still more preferably 100 nm or less, particularly preferably 70 nm or less. By having such an average primary particle diameter, sufficient fracture strength and wear resistance can be ensured.

- (D-2) Component: Carbon black The present composition preferably contains carbon black from the viewpoint of fracture characteristics and wear resistance of the polymer composition. Carbon black is not particularly limited, and includes, for example, GPF, FEF, HAF, ISAF, and SAF grade carbon black. The nitrogen adsorption specific surface area (N2SA) of carbon black is not particularly limited, but is preferably 50 to 200 m ² /g, more preferably 70 to 150 m ² /g. Nitrogen adsorption specific surface area (N ₂ SA) is the value obtained by measuring the amount of nitrogen adsorbed on the carbon black surface in accordance with JIS K6217-2:2001 "Part 2: How to determine specific surface area - Nitrogen adsorption method - Single point method" It is. One type of carbon black may be used alone, or two or more types may be used in combination. The amount of carbon black in the present composition is preferably in the range of 1 to 150 parts by weight, more preferably in the range of 5 to 120 parts by weight, based on 100 parts by weight of the conjugated diene polymer (A).

- (D-3) Component: Other fillers The present composition may contain other fillers in addition to silica and carbon black as inorganic fillers. Other fillers include alumina (Al ₂ O ₃ ) such as γ-alumina and α-alumina, alumina monohydrate (Al ₂ O ₃ H ₂ O) such as boehmite and diaspore, gibbsite, bayerite, etc. Aluminum hydroxide [Al(OH) ₃ ], aluminum carbonate [Al ₂ (CO ₃ ) ₃ ], magnesium hydroxide [Mg(OH) ₂ ], magnesium oxide (MgO), magnesium carbonate (MgCO ₃ ), talc ( 3MgO・4SiO ₂・H ₂ O), attapulgite (5MgO・8SiO ₂・9H ₂ O), titanium white (TiO ₂ ), titanium black (TiO _2n-1 ), calcium oxide (CaO), calcium hydroxide [Ca( OH) ₂ ], magnesium aluminum oxide (MgO・Al ₂ O ₃ ), clay (Al ₂ O ₃・2SiO ₂ ), kaolin (Al ₂ O ₃・2SiO ₂・2H ₂ O), pyrophyllite (Al ₂ O _3.4SiO _2.H ₂ O), bentonite (Al ₂ _O _3.4SiO 2.2H ₂ O), aluminum silicate (Al ₂ SiO ₅ , Al _4.3SiO _4.5H ₂ O, etc.), magnesium silicate ( _Mg2SiO4 _, _MgSiO3 , etc.), calcium silicate (Ca2SiO4 _, _etc. ₎ , aluminum calcium silicate ( _{Al2O3.CaO.2SiO2} _{, etc.} ), magnesium calcium silicate ( _CaMgSiO4 ), calcium carbonate ( CaCO ₃ ), zirconium oxide (ZrO ₂ ), zirconium hydroxide [ZrO(OH) ₂ ·nH ₂ O], zirconium carbonate [Zr(CO ₃ ) ₂ ], various zeolites, hydrogen and alkali to correct charge. Examples include crystalline aluminosilicates containing metals or alkaline earth metals.

In this composition, the amount of the inorganic filler containing silica and carbon black is preferably 30 parts by mass or more, more preferably 40 parts by mass, based on 100 parts by mass of the rubber component containing (A) the conjugated diene polymer. That's all. Further, the amount of the inorganic filler blended is preferably 150 parts by mass or less, more preferably 130 parts by mass or less, based on 100 parts by mass of the rubber component containing the conjugated diene polymer (A). If the amount of inorganic filler in this composition is within the above range, when this composition is applied to a tire tread, the tire will have low rolling resistance, braking performance on wet roads, and good performance on dry roads. It is possible to improve the handling performance and wear resistance in a more highly balanced manner.

・Component (E): Other rubber components Although the present composition may contain only (A) the conjugated diene polymer as a rubber component, in addition to the conjugated diene polymer (A), the present disclosure A rubber component different from the conjugated diene polymer (A) (hereinafter also referred to as "other rubber component") may be contained within a range that does not impair the effects of (A). Other rubber components include, for example, at least one diene rubber selected from natural rubber, isoprene rubber, butadiene rubber, emulsion polymerization or solution polymerization styrene-butadiene rubber, butyl rubber, halogenated butyl rubber, and ethylene-propylene rubber. can be used. Among these, other rubber components are preferably natural rubber, butadiene rubber, or styrene-butadiene rubber. The manner in which the other rubber components and (A) the conjugated diene polymer are mixed is not particularly limited. For example, the other rubber components and (A) the conjugated diene polymer may be mixed during the usual kneading using a Banbury mixer, rolls, etc., or the (A) conjugated diene polymer may be mixed with the (A) conjugated diene polymer after polymerization. Other rubber components may be mixed into the polymer solution containing the rubber, and then the solvent removal and drying steps may be performed.

The blending amount of other rubber components is preferably 80% by mass or less, and more preferably 80% by mass or less based on the total amount of rubber components ((A) conjugated diene polymer and other rubber components) contained in the polymer composition. Preferably it is 60% by mass or less.

In this composition, a liquid rubber can also be used as part or all of the other rubber components from the viewpoint of further improving dry grip performance, wet grip performance, and blowout resistance.

Examples of the liquid rubber include liquid polyisoprene (liquid IR), liquid polybutadiene (liquid BR), liquid styrene-butadiene copolymer (liquid SBR), and liquid ethylene-propylene copolymer (liquid EP). For example, liquid SBR having a weight average molecular weight of 1,000 to 100,000, preferably 2,000 to 80,000 can be used. In addition, in this specification, the weight average molecular weight means the weight average molecular weight in terms of polystyrene analyzed by gel permeation chromatography (GPC). Note that the liquid rubber used in this composition refers to one that has fluidity at 23°C.

- (F) component: Thermoplastic/thermosetting resin The present composition may contain a thermoplastic/thermosetting resin (hereinafter also simply referred to as "(F) resin"). (F) Resins include styrene resins, polyethylene, C5 resins, C9 resins, C5/C9 resins, from the viewpoint of obtaining crosslinked products with excellent properties such as strength, abrasion resistance, and crack growth resistance. It is preferably at least one selected from the group consisting of dicyclopentadiene resins, alkylphenol resins, and terpene resins. (F) As the resin, one type may be used alone, or two or more types may be used in combination.

Here, the styrenic resin is a polymer obtained using a styrene monomer, and in particular, the structural units derived from the styrenic monomer are added to the total amount of monomer units possessed by the styrenic resin. It is preferable that the polymer contains 20% by mass or more. Styrenic monomers include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o-chloro Examples include styrene, m-chlorostyrene, p-chlorostyrene, and the like. Among these, the styrenic monomer is preferably at least one of styrene and α-methylstyrene.

The styrenic resin may be a homopolymer obtained by polymerizing one type of styrenic monomer, or a copolymer obtained by copolymerizing two or more types of styrenic monomers. The styrenic resin may also be a copolymer obtained using a styrene monomer and another monomer that can be copolymerized with the styrene monomer. Other monomers include acrylonitriles such as acrylonitrile and methacrylonitrile; unsaturated carboxylic acids such as acrylics and methacrylic acid; unsaturated carboxylic acid esters such as methyl acrylate and methyl methacrylate; chloroprene and butadiene isoprene. dienes such as; olefins such as 1-butene and 1-pentene; α,β-unsaturated carboxylic acids such as maleic anhydride or acid anhydrides thereof, and the like.

The softening point of the styrene resin is preferably 30°C or higher, more preferably 60°C or higher, and even more preferably 80°C or higher. When the softening point is 30° C. or higher, the effect of improving crack growth resistance tends to be easily obtained in the crosslinked body. Further, the softening point of the styrene resin is preferably 160°C or lower, more preferably 130°C or lower, and even more preferably 100°C or lower. When the softening point is 160° C. or less, the dispersibility of the resin becomes good, and crack growth resistance, abrasion resistance, and breaking strength tend to be improved. In addition, in this disclosure, the softening point of the styrene resin is a value measured using a ring and ball softening point measuring device according to the method specified in JIS K 6220-1:2015, and the softening point of the styrene resin is a value measured using a ring and ball softening point measuring device. This is the temperature when the ball falls onto the bottom plate.

As the styrene resin, a block polymer (thermoplastic elastomer) having a conjugated diene polymer block as a soft segment and a polystyrene block as a hard segment can also be used. When such a block polymer is used, the effect of improving crack growth resistance can be increased, which is preferable. In addition, in the conjugated diene polymer block included in the block polymer, a portion of the carbon-carbon double bonds in the structural unit derived from the conjugated diene compound may be hydrogenated.

Examples of the conjugated diene compound constituting the conjugated diene polymer block include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and 1,3-hexadiene. Can be mentioned. As the conjugated diene compound, one kind can be used alone or two or more kinds can be used in combination. Among these, the conjugated diene compound is preferably at least one of 1,3-butadiene and isoprene. The content of conjugated diene units in the block polymer is preferably 20% by mass or more, more preferably 30% by mass or more. Moreover, it is preferable that the content rate of a conjugated diene unit is 80 mass % or less, and it is more preferable that it is 70 mass % or less.

The content of the polystyrene block in the block polymer is preferably 20% by mass or more, since it can further increase the breaking strength. Moreover, it is preferable that the content rate of a polystyrene type block is 80 mass % or less, and it is more preferable that it is 70 mass % or less. Note that the respective content ratios of the polystyrene block, conjugated diene polymer block, and conjugated diene unit in the block polymer can be calculated from the integral ratio of the ¹ H-NMR spectrum.

Specific examples of the above block polymer include styrene-butadiene block copolymer, styrene-isoprene block copolymer, epoxidized product of styrene-butadiene block copolymer, styrene-butadiene block copolymer, or styrene-isoprene block copolymer. Examples include block copolymers in which a part of the conjugated diene polymer block included in the polymer is hydrogenated. More specifically, epoxies of styrene-butadiene-styrene block copolymers (SBS), styrene-isoprene-styrene block copolymers (SIS), styrene-butadiene-butylene-styrene block copolymers (SBBS), and styrene-butadiene-styrene block copolymers and hydrogenated products of these copolymers. Among these, SBS or SIS having a conjugated diene polymer block whose soft segment is not hydrogenated, or an epoxidized product of a styrene-butadiene-styrene block copolymer is preferably used as the block polymer because it is easily crosslinked. be able to.

Examples of polyethylene include low density polyethylene (LDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), and the like. The C5 resin is a solid polymer (C5 synthetic petroleum resin) obtained by polymerizing a C5 fraction using a Friedel-Crafts catalyst (AlCl ₃ , BF _{3 ,} etc.). Specific examples of C5 resins include copolymers containing isoprene, cyclopentadiene, 1,3-pentadiene, and 1-pentene as main components, copolymers of 2-pentene and dicyclopentadiene, and 1,3-pentadiene. Examples include polymers containing pentadiene as a main component.

The C9 resin is a solid polymer (C9 synthetic petroleum resin) obtained by polymerizing a C9 fraction using a Friedel-Crafts catalyst (AlCl ₃ , BF _{3 ,} etc.). Specific examples of C9-based resins include copolymers containing indene, methylindene, vinyltoluene, etc. as main components. The C5/C9 resin is a solid polymer (C5/C9 synthetic petroleum resin) obtained by polymerizing C5 to C9 fractions using a Friedel-Crafts catalyst (AlCl ₃ , BF _3, etc.). Specific examples of C5/C9 resins include copolymers containing vinyltoluene, indene, etc. as main components. As the C5/C9 resin, a resin containing a small amount of C9 or higher components is preferable from the viewpoint of compatibility with the rubber component. Specifically, in the C5/C9 resin, the content of C9 or higher components in the total amount of the resin is preferably less than 50% by mass, and more preferably 40% by mass or less.

Dicyclopentadiene resin is a petroleum resin that uses dicyclopentadiene in the C5 fraction as the main raw material. Specific examples of dicyclopentadiene-based resins include Marukaretz M series (M-890A, M-845A, M-990A, etc.) manufactured by Maruzen Petrochemical Co., Ltd. Examples of the alkylphenol resin include alkylphenol-acetylene resin such as p-tert-butylphenol-acetylene resin, alkylphenol-formaldehyde resin with a low degree of polymerization, and the like.

Terpene resin is a solid resin obtained by blending turpentine oil, which is obtained at the same time as rosin from Pine trees, or polymerization components separated from this oil, and polymerizing it using a Friedel-Crafts type catalyst. Examples include β-pinene resin and α-pinene resin. As the terpene resin, commercial products can be used, such as the "YS Resin" series (PX-1250, TR-105, etc.) manufactured by Yasuhara Chemical Co., Ltd., and the "Picolite" manufactured by Hercules Corporation. series (A115, S115, etc.).

A typical example of the terpene-aromatic compound resin is a terpene-phenol resin. This terpene-phenol resin can be obtained by a method in which terpenes and various phenols are reacted using a Friedel-Crafts type catalyst, or further condensed with formalin. There are no particular restrictions on the terpenes used as raw materials, but monoterpene hydrocarbons such as α-pinene and limonene are preferred, those containing α-pinene are more preferred, and α-pinene is particularly preferred. Further, as the terpene-phenol resin, a terpene-phenol resin having a small proportion of phenol component is suitable. Here, "the ratio of the phenol component is small" refers to the fact that the phenol component in the total amount of the resin is less than 50% by mass, preferably 40% by mass or less. Note that if a terpene-aromatic compound resin, particularly a terpene-phenol resin, is used as the resin (F), the handling performance can be further improved. As the terpene-aromatic compound resin, commercially available products can be used. Examples of commercially available products include "Tamanol 803L", "Tamanol 901" (manufactured by Arakawa Chemical Co., Ltd.) under the trade name, "YS Polyster (registered trademark)" series (manufactured by Yasuhara Chemical Co., Ltd.), and the like.

The blending ratio of the resin (F) is preferably 1 part by mass or more based on 100 parts by mass of the rubber component contained in the present composition. By blending 1 part by mass or more of (F) resin, the effects of improving wear resistance, breaking strength, and crack growth resistance due to the addition of (F) resin can be sufficiently achieved in the crosslinked product obtained using the present composition. It is suitable because it can be made high. The blending ratio of the resin (F) is more preferably 3 parts by mass or more, and even more preferably 7 parts by mass or more, based on 100 parts by mass of the rubber component. In addition, the blending ratio of (F) resin is preferably 50 parts by mass or less based on 100 parts by mass of the rubber component contained in the composition, from the viewpoint of maintaining good performance of the composition. The amount is preferably 30 parts by mass or less, and still more preferably 25 parts by mass or less. In addition, as the resin (F), one type may be used alone, or two or more types may be used in combination.

- Component (G): Silane coupling agent In this composition, a silane coupling agent may be blended to further improve the dispersibility of silica. The silane coupling agent used is not particularly limited. The silane coupling agent is preferably a sulfur-containing silane coupling agent, such as bis(3-triethoxysilylpropyl)tetrasulfide, bis(3-triethoxysilylpropyl)disulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, Examples include γ-mercaptopropyltriethoxysilane and 3-octanoylthiopropyltriethoxysilane.

The amount of the silane coupling agent blended is preferably 1 to 20 parts by mass based on 100 parts by mass of silica contained in the present composition. If the amount of the silane coupling agent is less than 1 part by mass, there is a concern that the effect of improving the dispersibility of silica will be reduced due to the small amount of the silane coupling agent. On the other hand, if the amount of the silane coupling agent exceeds 20 parts by mass, the processability of the polymer composition and the elongation at break of the crosslinked product may decrease. The blending amount of the silane coupling agent is more preferably 5 to 15 parts by mass based on 100 parts by mass of silica contained in the present composition.

- Component (H): Crosslinking agent The present composition may contain a crosslinking agent. By containing the crosslinking agent in the present composition, a crosslinked product with improved strength and wear resistance can be obtained. Examples of the crosslinking agent include sulfur, halogenated sulfur, organic peroxides, quinone dioximes, organic polyvalent amine compounds, alkylphenol resins having a methylol group, and sulfur is usually used. The amount of the crosslinking agent blended is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the total amount of rubber components contained in the composition.

- Component (I): Extender oil A process oil that is generally used for extending elastomers may be blended into the present composition as an oil for oil extension (extender oil). The method of adding process oil is not particularly limited. For example, it may be compounded as an oil-extended rubber by spreading process oil in a conjugated diene polymer solution after polymerization and then removing the process oil, or it may be compounded as an oil-extended rubber by spreading the process oil into the conjugated diene polymer solution after polymerization, or by adding process oil to the conjugated diene polymer solution during kneading to obtain a rubber compound (compounded rubber). Processing oils may be incorporated into the polymer composition by adding the oil directly. Preferred process oils include a variety of oils known in the art, such as aromatic oils, paraffinic oils, naphthenic oils, vegetable oils, and oils with a low content of polycyclic aromatics (low polyaromatics). PCA oil), e.g. mild extraction solvate (MES), treated distillate aromatic extract (TDAE) from distillate oil, special aromatic extraction from residual oil. (SRAE: special residual aromatic extract), heavy naphthenic oil, etc. Examples of commercially available MES, TDAE and SRAE include Catenex SNR (heavy paraffin made by solvent dewaxing of distillate) from Shell as MES, Vivatec 500 from H&R Wasag AG as TDAE, and Japan Energy Corp as SRAE. Examples include NC140 manufactured by . The amount of process oil blended is preferably 10 to 100 parts by mass based on 100 parts by mass of the total amount of polymer components contained in the polymer composition.

In addition to the above-mentioned components, this composition also contains vulcanized rubber, such as zinc white, stearic acid, softeners, vulcanization accelerators, compatibilizers, vulcanization aids, processing aids, and scorch inhibitors. Various additives commonly used in polymer compositions for obtaining can be blended. These blending ratios can be appropriately selected depending on the various components within a range that does not impair the effects of the present disclosure.

《Production method of polymer composition》
The present composition can be obtained by mixing (A) the conjugated diene polymer and (B) the compound. The manner in which the present composition is obtained by mixing the conjugated diene polymer (A) and the compound (B) is not particularly limited. (A) The effect of suppressing the change in Mooney viscosity of the (A) conjugated diene polymer obtained by desolvation with respect to the difference in desolvation time of the conjugated diene polymer, and the heat storage combustion due to equipment contamination during drying treatment. From the viewpoint of obtaining the effect of suppressing the volatilization of the components, the present composition is capable of reducing (A) the conjugated diene polymer by adding the (B) compound to a polymer solution containing the (A) conjugated diene polymer after polymerization. It is preferable that the mixture is obtained by mixing the combined substance and the compound (B), and then removing the solvent and drying.

Specifically, the present composition is preferably manufactured by a method including Step A, Step B, and Step C below.
Step A: By polymerizing a monomer containing a conjugated diene compound and an aromatic vinyl compound in the presence of an alkali metal or an alkaline earth metal and hydrogenating it, (A) a polymer solution containing a conjugated diene polymer. The process of obtaining
Step B: A step of mixing the polymer solution obtained in Step A and the (B) compound to obtain a mixed solution containing the (A) conjugated diene polymer and the (B) compound.
Step C: A step of removing the solvent from the liquid mixture obtained in Step B and drying it.

Step A is a step that includes the above-mentioned polymerization step and hydrogenation step, and optionally includes one or both of a reaction step and a modification step. The above description applies to the details of each step.

In Step B, from the viewpoint of simplifying the manufacturing process, the polymer solution containing the (A) conjugated diene polymer obtained in Step A is used as it is, and the polymer solution and the (B) compound are mixed. It is preferable. The amount of the compound (B) is as described above. When (C) a specific stabilizer is blended into the present composition, the (C) specific stabilizer is blended during kneading to obtain a blended composition (so-called compounded rubber), thereby combining (A) with a conjugated diene polymer. (C) It may be mixed with a specific stabilizer. Alternatively, in step B, the (A) conjugated diene polymer and (C) the specific stabilizer may be mixed by adding the (C) specific stabilizer to the polymer solution. The latter method (an embodiment in which the specific stabilizer (C) is added to the polymer solution in step B) is preferable in that the effect of blending the specific stabilizer (C) can be sufficiently enhanced. When (C) the specific stabilizer is added to the polymer solution in step B, the (C) specific stabilizer may be added to the polymer solution at the same time as the (B) compound, or the (B) specific stabilizer may be added to the polymer solution before or after the addition of the compound. (C) A specific stabilizer may be added to the polymer solution later. The amount of the compound (C) is as described above.

In Step C, the method of removing the solvent from the liquid mixture containing the conjugated diene polymer (A) and the compound (B) and drying the mixture is not particularly limited. The solvent can be removed from the mixed solution and dried by known desolvation operations such as steam stripping and drying operations such as heat treatment.

According to Steps A to C, a solid polymer composition from which the solvent has been removed (hereinafter also referred to as "polymer composition P") can be obtained as one embodiment of the present composition. The polymer composition P may be solid particles (crumbs), or may be rubber veils obtained by compression molding crumbs into a desired shape (for example, a rectangular parallelepiped shape). In the polymer composition P, the total content of (A) the conjugated diene polymer, (B) the compound, and (I) the extender oil that is optionally blended is 95% by mass or more based on the entire composition. The content is preferably 97% by mass or more, and more preferably 97% by mass or more.

By blending the above-mentioned various components ((D) to (I) components, etc.) into the obtained polymer composition P as necessary, it can be made into a blended composition as another embodiment of the present composition. A polymer composition or blended composition (hereinafter also referred to as "polymer composition Q") can be obtained. The blended composition is prepared by mixing the polymer composition P with various additives (components (D) to (I), etc.) that are optionally used in a polymer composition for obtaining a vulcanized rubber, and preferably It can be obtained by kneading using a kneader such as a type kneader (for example, a roll) or an internal kneader (for example, a Banbury mixer). By crosslinking (vulcanizing) the compounded rubber thus obtained after molding, a crosslinked product (ie, vulcanized rubber) is obtained.

A crosslinked product obtained using the polymer composition of the present disclosure containing (A) a conjugated diene polymer and (B) a compound can be applied to various rubber products. Specifically, the crosslinked product obtained using the present composition can be used, for example, in tire applications such as tire treads, undertreads, carcass, sidewalls, and bead parts; seals such as packings, gaskets, weather strips, and O-rings. Materials: Interior and exterior skin materials for various vehicles such as automobiles, ships, aircraft, and railways; Building materials; Anti-vibration rubbers for industrial machinery and equipment; Various hoses such as diaphragms, rolls, radiator hoses, air hoses, etc. It can be applied to hose covers; belts such as power transmission belts; linings; dust boots; medical equipment materials; fenders; insulating materials for electric wires; and other industrial products.

According to the polymer composition of the present disclosure containing (A) a conjugated diene polymer and (B) a compound, it is possible to suppress the adhesion of the (A) conjugated diene polymer to equipment during drying treatment, and also to prevent the adhesion of the equipment to equipment. It is possible to suppress thermal storage combustion and volatilization of components due to the polymer, and to obtain a crosslinked product that has good physical properties required for tire applications, such as tensile strength, abrasion resistance, and viscoelastic properties, while easing the process load in the manufacturing process. can. Therefore, a polymer composition containing (A) a conjugated diene polymer and (B) a compound can be particularly suitably used as a material for a tire tread, a sidewall, or both.

Tires can be manufactured according to conventional methods. For example, a polymer composition is mixed in a kneading machine and formed into a sheet, which is then placed in a predetermined position (for example, outside the carcass in the case of sidewalls) and vulcanized to form a tread. Alternatively, it can be formed as a sidewall to obtain a pneumatic tire.

According to the present disclosure described above, the following means are provided.
[Means 1] (A) A structural unit represented by the above formula (1), a structural unit represented by the above formula (2), a structural unit represented by the above formula (3), and a structural unit represented by the above formula (4). When the composition ratio (mole ratio) of the structural units in the polymer is p, q, r, and s, the value α represented by the above formula (i) is 0.60 to 0.98, A conjugated diene polymer having a structural unit derived from a conjugated diene compound and a structural unit derived from an aromatic vinyl compound, and (B) a hindered phenol compound having a molecular weight of 250 to 2,000, A) A polymer composition in which part or all of the components have a functional group containing at least one element selected from the group consisting of nitrogen, oxygen, sulfur, and phosphorus.
[Means 2] The polymer composition according to [Means 1], wherein the content of the component (B) is 0.1 to 2.2 parts by mass based on 100 parts by mass of the component (A).
[Means 3] The polymer composition according to [Means 1] or [Means 2], wherein the proportion of nitrogen contained in the component (A) is 50 ppm or more based on the total amount of the component (A).
[Means 4] The polymer composition according to any one of [Means 1] to [Means 3], wherein the component (A) has a polymer block portion containing 80% by mass or more of structural units derived from an aromatic vinyl compound. thing.
[Means 5] The polymer composition according to any one of [Means 1] to [Means 4], which contains a branched polymer having a branch number of 4 or more as the component (A).
[Means 6] The polymer composition according to [Means 5], wherein the proportion of the branched polymer having a branch number of 4 or more is 15% by mass or more based on the total amount of the component (A).
[Means 7] The polymer composition according to any one of [Means 1] to [Means 6], wherein the component (B) has a molecular weight of 350 to 1,200.
[Means 8] The polymer composition according to any one of [Means 1] to [Means 7], which contains a compound having a carbon-carbon unsaturated bond as the component (B).
[Means 9] [Means 1] to [Means 8] further containing at least one component selected from the group consisting of phosphorus stabilizers and organic sulfur stabilizers and having a molecular weight of 250 to 2,000. ] The polymer composition according to any one of the above.
[Means 10] The polymer composition according to any one of [Means 1] to [Means 9], wherein the value α is 0.75 to 0.92.
[Means 11] [Means 1] to [Means 1], wherein the total content of the component (A), the component (B), and the optionally added extender oil is 95% by mass or more based on the entire composition. The polymer composition according to any one of means 10].
[Means 12] The polymer composition according to any one of [Means 1] to [Means 10], further containing an inorganic filler.
[Means 13] A crosslinked product obtained by crosslinking the polymer composition according to any one of [Means 1] to [Means 10] and [Means 12].
[Means 14] A tire in which a tread, a sidewall, or both are formed using the polymer composition according to any one of [Means 1] to [Means 10] and [Means 12].
[Means 15] A method for producing the polymer composition according to any one of [Means 1] to [Means 12], comprising: a conjugated diene compound and an aromatic vinyl compound in the presence of an alkali metal or an alkaline earth metal; A step of obtaining a polymer solution containing the component (A) by polymerizing and hydrogenating a monomer containing the component (A); A method for producing a polymer composition, comprising the steps of: obtaining a mixed solution containing the component and the component (B); and removing the solvent from the mixed solution and drying it.

Hereinafter, the present disclosure will be specifically described based on Examples, but the present disclosure is not limited to these Examples. Note that "parts" and "%" in Examples and Comparative Examples are based on mass unless otherwise specified. The methods for measuring various physical property values of the polymer are shown below.

[Polymer property evaluation]
- Vinyl bond content (mol %): Measured by ¹ H-NMR at 400 MHz for the polymer before hydrogenation.
- Bound styrene content (%): Measured by ¹ H-NMR at 400 MHz for the polymer before hydrogenation.
・1st peak molecular weight: For the polymer before hydrogenation, use a gel permeation chromatograph (GPC, product name: HLC-8020, manufactured by Tosoh Corporation) to obtain a chart based on the molecular weight in terms of polystyrene. It was determined from the retention time of the peak with the longest retention time in the GPC curve obtained. The specific measurement conditions are as follows.
(Measurement condition)
Column: Two GMH-HR-H (manufactured by Tosoh Corporation) were connected in series.
Detector: Differential refractometer RI-8020 (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Column temperature: 40°C
Flow rate: 1.0 mL/min Sample concentration: 10 mg/20 mL
- Total average molecular weight: Determined in terms of polystyrene from all peaks of a GPC curve obtained using GPC (product name: HLC-8020, manufactured by Tosoh Corporation) for the polymer before hydrogenation. The measurement conditions were the same as above.
・Coupling rate (mass%): From the GPC curve obtained using GPC (product name: HLC-8020, manufactured by Tosoh Corporation) for the polymer before hydrogenation, it was determined that two or more linear conjugates The waveform of the molecule to which the molecular chains of the diene polymer were bonded was separated into components and calculated from the peak area ratio.
- Hydrogenation rate and α: Calculated from ¹ H-NMR spectrum measured with a 100 MHz device using ethylene tetrachloride as a solvent.
・Content of branched polymer with 4 branches or more (mass%): Based on the GPC curve obtained using GPC (product name: HLC-8020, manufactured by Tosoh Corporation) for the polymer before hydrogenation, 4 branches or more The waveform of the molecule to which the molecular chains of the linear conjugated diene polymer were bonded was separated into components, and the calculation was made from the peak area ratio.
・Content of modified polymer (mass%): Calculated by adding the coupling ratio (C/E) to the proportion of linear polymer modified with terminal modifier (W1) (content of modified polymer = W1+C/E). The ratio W1 is the number of moles of the polymerization initiator (M1) used in the production of the polymer, the number of moles of the coupling agent (M2), and the number of moles of the amount of the terminal modifier consumed during modification with the terminal modifier (M3). and the coupling ratio (C/E) using the following formula.
W1 [%] = (100-C/E) x M3/(M1-4 x M2)
The number of moles (M3) of the terminal modifier consumed during modification with the terminal modifier was calculated by quantifying the unreacted terminal modifier by gas chromatography measurement of the polymer solution after the modification reaction.
- Nitrogen content (ppm): Measured according to the chemiluminescence method of JIS K2609:1998 (Crude oil and petroleum products - Nitrogen content test method). In detail, using a trace total nitrogen analyzer (“TN-2100H” manufactured by Mitsubishi Chemical Analytech), the sample was thermally decomposed under argon gas flow, and then the sample was oxidized by combustion in an oxygen atmosphere. The nitrogen monoxide reacted with ozone gas under dehydration conditions, the detected luminescence intensity in the range of 590 to 2500 nm was measured, and the nitrogen content was calculated from the area of the luminescence intensity.

<Production of conjugated diene polymer>
[Production Example 1: Production of hydrogenated conjugated diene polymer A-1 and its physical properties]
25,900 g of cyclohexane, 65 g of tetrahydrofuran, 0.6 g of potassium dodecylbenzenesulfonate, 740 g of styrene, 2,849 g of 1,3-butadiene, and 30 mmol of piperidine were charged into a 50-liter autoclave reactor purged with nitrogen. After adjusting the temperature of the contents of the reactor to 42° C., a cyclohexane solution containing n-butyllithium (39 mmol) was added to initiate polymerization. Polymerization was carried out under adiabatic conditions. After the polymerization conversion rate reached 99%, 111 g of 1,3-butadiene was added (additional butadiene), and polymerization was further carried out for 3 minutes to obtain a reaction solution containing a polymer. To the obtained reaction solution, 2.0 mmol of tetrachlorosilane was added and reacted for 5 minutes, and further, 28 mmol of N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane was added and reacted for 15 minutes.
Next, the reaction solution was heated to 80° C. or higher, hydrogen was introduced into the system, and the reaction was allowed to proceed for 1 hour. A small amount of the polymer solution was extracted from the reaction vessel to obtain a conjugated diene polymer before hydrogenation for analysis. Then, 1.64 g of diethylaluminum chloride, 3.67 g of bis(η5-cyclopentadienyl) titanium (furfuryloxy) chloride, and 1.67 g of n-butyllithium were added, and water was added while maintaining the hydrogen pressure of 1.0 MPa. An addition reaction was performed. After the reaction, the hydrogen pressure is maintained at 0.7 MPa or more and hydrogen is supplied until a predetermined integrated hydrogen value is reached.Then, the reaction solution is returned to room temperature and pressure and taken out from the reaction vessel, and then hydrogenated. A polymer solution containing conjugated diene polymer A-1 was obtained. A small amount of the obtained polymer solution was extracted, the solvent was removed by steam stripping, and the solution was dried using a heated roll whose temperature was controlled to 130° C. to obtain a hydrogenated conjugated diene polymer A-1. Table 1 shows the polymerization recipe of hydrogenated conjugated diene polymer A-1, and Table 3 shows various physical property values of hydrogenated conjugated diene polymer A-1.

[Production Examples 2 to 11, Production Examples 13 to 15, Comparative Production Examples 1 to 5: Production of hydrogenated conjugated diene polymer and its physical properties]
Hydrogenated conjugated diene polymer A was produced in the same manner as in Production Example 1, except that the polymerization recipe was changed as shown in Tables 1 and 2, and the hydrogenation rate was changed as shown in Tables 3 and 4. A polymer solution containing -2 to A-11, A-13 to A-18, A-21, and A-22 was obtained. In addition, in Production Examples 2 to 11 and 13 to 15, hydrogenated conjugated diene polymers A-2 to A-11, A-13, A-21, and A-22 were produced, respectively, and in Comparative Production Examples 2 to 5, Hydrogenated conjugated diene polymers A-14 to A-18 were produced, respectively. Tables 3 and 4 show various physical property values of hydrogenated conjugated diene polymers A-2 to A-11, A-13 to A-18, A-21, and A-22.

[Production Example 12: Production of hydrogenated conjugated diene polymer A-12 and its physical properties]
A 50-liter autoclave reactor purged with nitrogen was charged with 25,900 g of cyclohexane, 600 g of styrene, 65 g of tetrahydrofuran, and 30 mmol of piperidine. A cyclohexane solution containing 39 mmol of n-butyllithium was charged, and polymerization was carried out under adiabatic conditions at a polymerization initiation temperature of 40°C. After the polymerization conversion rate reached 99% or more, the reaction solution was cooled to 30° C., 700 g of styrene and 2,289 g of 1,3-butadiene were added, and further polymerization was carried out. After the polymerization conversion rate reached 99% or more, 111 g of 1,3-butadiene was added and polymerization was continued for an additional 3 minutes to obtain a reaction solution containing a polymer. To the obtained reaction solution, 2.0 mmol of tetrachlorosilane was added and reacted for 5 minutes, and further, 28 mmol of N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane was added and reacted for 15 minutes. Next, the reaction solution was heated to 80° C. or higher, hydrogen was introduced into the system, and the reaction was allowed to proceed for 1 hour. A small amount of the polymer solution was extracted from the reaction vessel to obtain a conjugated diene polymer before hydrogenation. Add 1.64 g of diethylaluminum chloride, 3.67 g of bis(η5-cyclopentadienyl) titanium (furfuryloxy) chloride, and 1.67 g of n-butyllithium, and conduct a hydrogenation reaction while maintaining the hydrogen pressure of 1.0 MPa. I did it. After the reaction, the hydrogen pressure is maintained at 0.7 MPa or more and hydrogen is supplied until a predetermined integrated hydrogen value is reached.Then, the reaction solution is returned to room temperature and pressure and taken out from the reaction vessel, and then hydrogenated. A polymer solution containing conjugated diene polymer A-12 was obtained. A small amount of the obtained polymer solution was extracted, the solvent was removed by steam stripping, and the solution was dried using a heated roll whose temperature was controlled to 130° C. to obtain hydrogenated conjugated diene polymer A-12. The polymerization recipe of hydrogenated conjugated diene polymer A-12 is shown in Table 2, and various physical property values of hydrogenated conjugated diene polymer A-12 are shown in Table 4.

[Comparative Production Examples 6 and 7: Production of hydrogenated conjugated diene polymers A-19 and A-20 and their physical properties]
Hydrogenated conjugated diene polymer A-19,A was produced in the same manner as in Production Example 12 except that the polymerization recipe was changed as shown in Table 2 and the hydrogenation rate was changed as shown in Table 4 A polymer solution containing -20 was obtained. Table 4 shows various physical properties of hydrogenated conjugated diene polymers A-19 and A-20.

In Tables 1 and 2, "-" means that the compound in the corresponding column was not used. The abbreviations of the vinyl content adjuster, starting end modifying agent, end modifying agent, and coupling agent are as follows.
V-1: Potassium dodecylbenzenesulfonate INI-1: Piperidine Md-1: N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane Cp-1: Tetrachlorosilane

<Production of polymer composition and crosslinked product>
[Example 1]
・Production of polymer composition P To the polymer solution containing the hydrogenated conjugated diene polymer A-1 obtained in Production Example 1, for 100 parts by mass of the hydrogenated conjugated diene polymer A-1, 0.2 parts by mass of hindered phenol compound B-1 as component (B), 0.3 parts by mass of hindered phenol compound B-2, and 0.3 parts by mass of phosphoric acid ester compound C-1 as component (C). Parts by mass were mixed. The resulting mixed solution was desolvented for 2 hours by steam stripping, and dried using a heated roll whose temperature was controlled at 130°C, resulting in hydrogenated conjugated diene polymer A-1 and hindered phenol compound B. -1, a hindered phenol compound B-2, and a phosphoric acid ester compound C-1. Table 5 shows the formulation of polymer composition P-1.

・Production of polymer composition Q and crosslinked product Using the polymer composition P-1 produced above, each component is blended according to the formulation shown in Table 7, and the polymer composition is prepared by kneading this. Q-1 was manufactured. Kneading was performed in the following manner. Using a plastomill (capacity: 250 mL) equipped with a temperature control device, the polymer composition P-1, silica, and carbon black were kneaded in the first stage at a filling rate of 72% and a rotation speed of 60 rpm. , silane coupling agent, extender oil, stearic acid, zinc oxide, and anti-aging agent were mixed and kneaded. Next, in the second stage of kneading, the mixture obtained above was cooled to room temperature, and then a vulcanization accelerator and sulfur were added thereto and kneaded. The kneaded polymer composition Q-1 was molded and vulcanized in a vulcanization press at 160° C. for a predetermined time to obtain a crosslinked product (vulcanized rubber). In addition, as a manufacturing process evaluation, we evaluated the MV change rate, thermal storage combustion suppression ability, volatility, and equipment adhesion by extending the desolution time as shown below, and as a blend physical property evaluation, we evaluated the tensile strength of the obtained crosslinked product, Abrasion resistance, rolling resistance and vulcanization adhesion were evaluated. The results are shown in Table 8.

(1) MV change rate due to extension of desolvation time Polymer composition P' was obtained in the same manner as in the production of polymer composition P except that the steam stripping time was changed from 2 hours to 8 hours. Mooney viscosity (MV) was measured for each of polymer composition P and polymer composition P', and MV measurement values (MV-P, MV-P') were obtained, respectively. Mooney viscosity was measured in accordance with JIS K6300-1 using an L rotor under conditions of preheating for 1 minute, rotor operating time for 4 minutes, and temperature of 100°C.
Using the MV measurement values (MV-P, MV-P'), the MV change rate was calculated using the following formula.
MV change rate = MV-P'/MV-P
We believe that the smaller the value of the obtained MV change rate is, the closer it is to 1.0, the better the quality stability in the desolution process, and the more useful it is to reduce the burden on process control. Judging from ~C.
AA: 0.8 or more and less than 1.2 A: 1.2 or more and less than 1.5 B: 1.5 or more and less than 2.0 C: 2.0 or more or less than 0.8

(2) Heat storage combustion suppression property 350 g of polymer composition P was cut into 0.5 cm square pieces to obtain square crumbs. A square crumb was placed in a SUS wire mesh with a diameter of 10 cm, and a thermocouple for temperature measurement was placed in a gear oven so as to be in contact with the square crumb. The gear oven was operated at a setting of 170° C., and the highest temperature reached by the thermocouple was measured during ventilation heating for 8 hours. The lower the maximum temperature reached, the greater the effect of suppressing heat accumulation and combustion, which reduces the risk of heat accumulation and ignition of polymer composition crumbs that adhere or remain inside and outside of drying ovens and extruders during the manufacturing process, and reduces the frequency of equipment cleanup. , it is possible to reduce the process load and can be judged to be useful. Based on the maximum temperature reached, heat storage combustion suppression performance was judged from A to C based on the following criteria.
A: The maximum temperature reached is less than 180°C. B: The maximum temperature reached is 180°C or more and less than 210°C, which is an acceptable range. C: The maximum temperature reached is 210°C or more, which is unacceptable.

(3) Volatility Using 10 mg of polymer composition P, 0.5% by weight thermogravimetrically measured from 40°C at a heating rate of 5°C/min under an air flow of 200 mL/min. The decreasing temperature (Td0.5) was determined. Here, the measurement temperature at which the weight loss of the polymer composition P reached 0.5% by weight was defined as the 0.5% by weight thermogravimetric loss temperature (Td0.5). The higher the Td0.5, the more volatile components around the drying oven and extruder can be suppressed in the manufacturing process, and the process load can be reduced, such as by suppressing deterioration of the working environment at the manufacturing site and reducing the frequency of equipment cleanup. It can be judged to be useful. From Td0.5, volatility was judged from A to C based on the following criteria.
A: 280°C or more B: 170°C or more and less than 280°C, acceptable range C: Less than 170°C, unacceptable

(4) Equipment adhesion (apron adhesion)
In the above "manufacturing of polymer composition P", instead of drying the polymer composition after desolvation by steam stripping using a heated roll whose temperature is controlled at 130°C, The composition was placed on a SUS wire mesh and heated in a hot air constant temperature bath at 120° C. for 1 hour to perform hot air drying. The condition when the dried polymer composition P was recovered from the SUS wire mesh was observed, and the equipment adhesion was judged from AA to C based on the following criteria.
AA: 99% or more of the polymer composition was recovered, and no adhesion of the polymer composition to the wire mesh was observed.
A: 97% or more and less than 99% of the polymer composition could be recovered, and there was little adhesion of the polymer composition to the wire mesh.
B: 95% or more and less than 97% of the polymer composition could be recovered, and there was a large amount of the polymer composition attached to the wire mesh.
C: The recovery rate of the polymer composition was less than 95%, and the polymer composition adhered to the wire mesh very often.
If the evaluation is between AA and B, it can be determined that the adhesion to equipment during the drying process using a band dryer, extruder, etc. during production of the polymer composition is at a practical level. A C judgment indicates that it does not reach a practical level.

(5) Tensile strength A tensile test was conducted using the crosslinked body as a measurement sample in accordance with JIS K6251:2010. Here, the stress at break (TB) and elongation at break (EB) were measured at room temperature using a dumbbell shape No. 3 as a test sample. The larger the values of TB and EB, the higher the breaking strength, indicating that the mechanical strength of the material is high and good. Evaluation was performed based on the TB value, and was evaluated using an index based on Comparative Example 1. It can be said that the larger the number, the higher the tensile strength, and the better the strength. From the obtained tensile strength values, the tensile strengths were judged from AA to C based on the following criteria.
AA: 110 or more A: 100 or more and less than 110 B: 80 or more and less than 100 and allowable range C: less than 80

(6) Abrasion resistance Using a crosslinked body as a measurement sample, measurement was performed at 25° C. under a load of 10 N using a DIN abrasion tester (manufactured by Toyo Seiki Co., Ltd.) in accordance with JIS K6264-2:2005. It was expressed as an index based on Comparative Example 1, and the rolling resistance was evaluated using the index. The larger the value, the higher the wear resistance and the better. From the obtained index, the wear resistance was judged from A to C based on the following criteria.
A: 115 or more B: 105 or more and less than 115 and allowable range C: less than 105

(7) Rolling resistance Using a crosslinked body as a measurement sample, measurements were made using a dynamic spectrometer (manufactured by Rheometrics, Inc., USA) under conditions of tensile dynamic strain of 0.7%, angular velocity of 100 radians per second, and 50°C. . It was expressed as an index based on Comparative Example 2, and rolling resistance was evaluated using the index. The larger the value, the lower the rolling resistance and the better. Based on the obtained index, rolling resistance was judged from AA to C based on the following criteria.
AA: 125 or more A: 115 or more and less than 125 B: 105 or more and less than 115 and allowable range C: less than 105

(8) Vulcanization adhesion A pre-vulcanized sheet of polymer composition Q and a pre-vulcanized sheet containing natural rubber as a main component are laminated with PET film sandwiched between the ends, and the temperature By vulcanizing at 170° C. for 15 minutes, a laminate vulcanized product was obtained in which the portions not sandwiching the PET film were vulcanized and bonded.
In order to measure the adhesive strength at a width of 15 mm, a strip-shaped sample piece was taken from the laminated vulcanizate from the part where PET was sandwiched to the part where PET was not sandwiched, and the PET film was removed to prepare a test piece. A vulcanized sheet made of polymer composition Q was placed on one side of an autograph tester equipped with a constant temperature bath, and a vulcanized sheet of natural rubber was placed on the other side, and the sheets were chucked up and down in an atmosphere of 70°C. A peel test was conducted at a speed of 50 mm/min to measure the adhesive strength. The obtained adhesive strength values were evaluated as an index based on Comparative Example 1. It can be said that the larger the value, the higher the adhesive force, and the better the vulcanization adhesion. Based on the obtained index, the vulcanization adhesion was judged from AA to C based on the following criteria.
AA: 140 or more A: 110 or more and less than 140 B: 90 or more and less than 110 C: Less than 90

[Examples 2 to 15, Comparative Examples 1 to 7]
In place of the polymer solution containing hydrogenated conjugated diene polymer A-1, each polymer solution containing hydrogenated conjugated diene polymers A-2 to A-22 was used, and the types and amounts of additives. Polymer compositions P-2 to P-22 were produced as polymer composition P in the same manner as in Example 1, except that the values were changed as shown in Tables 5 and 6. In addition, when producing the polymer composition P, in Examples 2 to 15, polymer solutions containing hydrogenated conjugated diene polymers A-2 to A-13, A-21, and A-22, respectively, were used, and in Comparative Example In Examples 1 to 7, polymer solutions containing hydrogenated conjugated diene polymers A-14 to A-20, respectively, were used. In addition, each component was mixed according to the formulation shown in Table 7 in the same manner as in Example 1 except that polymer compositions P-2 to P-22 were used instead of polymer composition P-1. Polymer compositions Q-2 to Q-22 were each produced by kneading. Further, crosslinked products were produced using each of the produced polymers Q-2 to Q-22, and various evaluations were conducted in the same manner as in Example 1. The results are shown in Tables 8 and 9.

In Tables 5 and 6, "-" means that the compound in the corresponding column was not used. The abbreviations of additives are as follows.
B-1: n-octadecyl-3-(4-hydroxyl-3,5-di-t-butylphenyl)-propionate B-2: 2-tert-butyl-6-(3-tert-butyl-2-hydroxy -5-methylbenzyl)-4-methylphenyl acrylate B-3: Pentaerythritol tetrakis [3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]
C-1: Tris(2,4-di-tert-butylphenyl)phosphite C-2: 2,2-bis({[3-(dodecylthio)propionyl]oxy}methyl)-1,3-propanediyl= Bis[3-(dodecylthio)propionate]
H-1: 2,6-di-tert-butyl-4-methylphenol

As shown in Tables 8 and 9, the polymer compositions of Examples 1 to 15 were evaluated as ``AA'' and ``A'' in terms of MV change rate, heat storage combustion suppression ability, volatility, and equipment adhesion due to extended desolvation time. ” or “B”. From these results, it can be said that the polymer compositions of Examples 1 to 15 can reduce the load in the manufacturing process and have good quality stability. In addition, the crosslinked products obtained from the polymer compositions of Examples 1 to 15 had improved tensile strength, abrasion resistance, rolling resistance, and vulcanization properties due to suppressed changes in the Mooney viscosity of the polymer during the manufacturing process. The evaluation of adhesive properties was also good, and various compounding characteristics were excellent.

On the other hand, the polymer compositions of Comparative Examples 1 and 7, in which unmodified hydrogenated conjugated diene polymers A-14 and A-20 were blended, were evaluated for manufacturing process (MV change rate due to extension of desolvation time, Although the properties (thermal storage combustion suppression, volatility, and equipment adhesion) were good, one or more of the compound properties (tensile strength, abrasion resistance, rolling resistance, and vulcanization adhesion) were rated "C". and was inferior to Examples 1 to 15. In addition, the polymer compositions of Comparative Examples 2 and 3 that do not contain a hindered phenol compound with a molecular weight of 250 or more, and Comparative Example 4 that contains hydrogenated conjugated diene polymers with a hydrogenation rate of 5% and 43%, respectively. The polymer compositions of Nos. and 5 were evaluated as "C" in one or more of the manufacturing process evaluation items, and were inferior in terms of manufacturing process load and quality stability. In addition, the compounding characteristics were rated "C" in one or more evaluation items. The polymer composition of Comparative Example 6 containing hydrogenated conjugated diene polymer A-19 with a hydrogenation rate of 99% had good manufacturing process evaluations, but The evaluation of adhesiveness was "C", and the compounding characteristics were poor.

From the above results, a conjugated diene polymer having a value of α represented by the above formula (1) of 0.60 or more and 0.98 or less and having a conjugated diene compound unit and an aromatic vinyl compound unit, containing a hindered phenol compound having a molecular weight of 250 to 2,000, and at least one polymer selected from the group consisting of nitrogen, oxygen, sulfur, and phosphorus, in which part or all of the polymer constituting the conjugated diene polymer According to a polymer composition having a specific functional group containing a species element, it is possible to reduce the process load and stabilize the quality in the production process of a conjugated diene polymer, and moreover, a crosslinked product with suppressed performance deterioration can be obtained. It has become clear that it can be obtained.

Claims

(A) Structural unit represented by the following formula (1), structural unit represented by the following formula (2), structural unit represented by the following formula (3), and structural unit represented by the following formula (4) When the composition ratio (molar ratio) in the polymer is p, q, r, and s, respectively, the value α expressed by the following formula (i) is 0.60 to 0.98, and the conjugated diene compound A conjugated diene polymer having a structural unit derived from the derivative and a structural unit derived from an aromatic vinyl compound, and
(B) contains a hindered phenol compound with a molecular weight of 250 to 2,000,
A polymer composition in which part or all of the component (A) has a functional group containing at least one element selected from the group consisting of nitrogen, oxygen, sulfur, and phosphorus.
α=(p+(0.5×r))/(p+q+(0.5×r)+s)
...(i)
The polymer composition according to claim 1, wherein the content of the component (B) is 0.1 to 2.2 parts by mass based on 100 parts by mass of the component (A).
The polymer composition according to claim 1, wherein the proportion of nitrogen contained in the component (A) is 50 ppm or more based on the total amount of the component (A).
The polymer composition according to claim 1, wherein the component (A) has a polymer block portion containing 80% by mass or more of a structural unit derived from an aromatic vinyl compound.
The polymer composition according to claim 1, wherein the component (A) contains a branched polymer having a branching number of 4 or more.
The polymer composition according to claim 5, wherein the proportion of the branched polymer having a branching number of 4 or more is 15% by mass or more based on the total amount of the component (A).
The polymer composition according to claim 1, wherein the molecular weight of the component (B) is 350 to 1,200.
The polymer composition according to claim 1, wherein the component (B) contains a compound having a carbon-carbon unsaturated bond.
The polymer composition according to claim 1, further comprising at least one component selected from the group consisting of phosphorus stabilizers and organic sulfur stabilizers and having a molecular weight of 250 to 2,000.
The polymer composition according to claim 1, wherein the value α is 0.75 to 0.92.
The polymer composition according to claim 1, wherein the total content of the (A) component, the (B) component, and optionally blended extender oil is 95% by mass or more based on the entire composition. .
The polymer composition according to claim 1, further comprising an inorganic filler.
A crosslinked product obtained by crosslinking the polymer composition according to any one of claims 1 to 10 and 12.
A tire having a tread, a sidewall, or both formed using the polymer composition according to any one of claims 1 to 10 and 12.
A method for producing a polymer composition according to any one of claims 1 to 12, comprising:
Polymerizing a monomer containing a conjugated diene compound and an aromatic vinyl compound in the presence of an alkali metal or an alkaline earth metal and hydrogenating it to obtain a polymer solution containing the component (A);
mixing the polymer solution and the component (B) to obtain a mixed solution containing the component (A) and the component (B);
removing the solvent from the liquid mixture and drying it;
A method for producing a polymer composition, comprising: