Polymer composition and cross-linked body

Abstract

To provide a polymer composition capable of obtaining a belt which has high intensity and is excellent in abrasion resistance and in heat resistance.SOLUTION: A polymer composition contains a rubber component (A) and carbon black (B). The rubber component (A) contains (A1) a conjugated diene-based polymer in which a value α represented by a mathematical formula (i) is 0.60 to 0.98 when constituent ratios (molar ratios) of a structural unit represented by formula (1), a structural unit represented by formula (2), a structural unit represented by formula (3), and a structural unit represented by formula (4) in the polymer are set to be p, q, r, and s, respectively, and (A2) 20 to 80 mass% of one or more components selected from the group consisting of natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, and ethylene-α-olefin copolymers, and contains 25 to 150 pts.mass of carbon black (B) based on 100 pts.mass of the rubber components (A). α=(p+(0.5×r)) / (p+q+(0.5×r)+s)...(i).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polymer composition, a crosslinked product thereof, and uses thereof. [Background technology]

[0002] Power transmission belts that transmit power have long been required to have high durability. Power transmission belts are often used in high-temperature environments and rotate at high speeds, which can cause internal heat generation due to deformation, making thermal degradation a problem (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2007-120759 Summary of the Invention [Problem to be solved by the invention]

[0004] Industrial belts such as power transmission belts require strength, but compounding a large amount of carbon black to increase strength increases heat generation and reduces durability, which is a problem.

[0005] The present invention has been made in view of the above problems, and an object of the present invention is to provide a polymer composition from which a belt having high strength and excellent abrasion resistance and heat resistance can be obtained. [Means for solving the problem]

[0006] The present invention provides the following polymer composition and crosslinked product.

[0007] [1] A polymer composition comprising (A) a rubber component and (B) carbon black, wherein the (A) rubber component comprises (A1) a conjugated diene-based polymer in which the value α represented by the following mathematical formula (i) is 0.60 to 0.98, where p, q, r, and s are the constituent ratios (molar ratios) in the polymer of 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), respectively; the (A) rubber component comprises 20 to 80 mass % of (A2) one or more components selected from the group consisting of natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, and ethylene-α-olefin copolymer; and 25 to 150 mass parts of (B) carbon black per 100 mass parts of the (A) rubber component. α=(p+(0.5×r)) / (p+q+(0.5×r)+s) …(i) [ka]

[0008] [2] The polymer composition according to [1], comprising, as the component (A1), a polymer having a functional group containing at least one element selected from the group consisting of nitrogen, oxygen, sulfur, phosphorus, tin, and silicon. [3] The polymer composition according to [1], wherein the proportion of the component (A1) is 10 to 100% by mass based on the total amount of the component (A). [4] The polymer composition according to [1], wherein the proportion of the component (A1) is 20 to 70 mass % based on the total amount of the component (A). [5] The polymer composition according to [1], wherein the (A) rubber component contains (A2) one or more components selected from the group consisting of natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, and ethylene-α-olefin copolymer. [6] The polymer composition according to [1], wherein the component (A1) is a polymer having a random copolymerization portion of a structural unit derived from a conjugated diene compound and a structural unit derived from an aromatic vinyl compound, and not having a block composed of a structural unit derived from an aromatic vinyl compound. [7] The polymer composition according to [1], further comprising a crosslinking agent. [8] A crosslinked product obtained by curing the polymer composition according to [7]. [9] An industrial belt using the crosslinked body according to [8] as at least a part thereof.

[10] A roll using the crosslinked body according to [8] at least in part.

[11] A wire coating material comprising the crosslinked body according to [8]. [Effects of the Invention]

[0009] According to the present invention, a crosslinked rubber having high strength and excellent heat resistance can be obtained, and various belts, rolls, electric wire covering materials, etc. having long life can be obtained. DETAILED DESCRIPTION OF THE INVENTION

[0010] Matters relating to the implementation of the present disclosure will be described in detail below. In this specification, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0011] <Polymer composition> The polymer composition of the present disclosure (hereinafter also referred to as "the composition") contains (A) a rubber component and (B) carbon black. The components contained in the composition and the components that may be optionally blended are described in detail below.

[0012] <Component (A1): Conjugated Diene Polymer> The conjugated diene polymer of component (A1) (hereinafter also referred to as "(A1) conjugated diene polymer") is a highly saturated polymer in which the value α represented by the following formula (i) is 0.50 to 0.98, where p, q, r, and s are the constituent ratios (molar ratios) in the polymer of the structural unit represented by the following formula (1), the structural unit represented by the following formula (2), the structural unit represented by the following formula (3), and the structural unit represented by the following formula (4), respectively. α=(p+(0.5×r)) / (p+q+(0.5×r)+s) …(i) [ka]

[0013] The conjugated diene polymer (A1) is a random copolymer having a random copolymerization portion in which structural units derived from a conjugated diene compound and structural units derived from an aromatic vinyl compound are randomly arranged, and does not have a block consisting of structural units derived from an aromatic vinyl compound.

[0014] The molecular structure of the (A1) conjugated diene polymer is not particularly limited as long as it is a copolymer having a random copolymerization portion of structural units derived from a conjugated diene compound and structural units derived from an aromatic vinyl compound. The (A1) conjugated diene polymer may be a linear polymer (hereinafter also referred to as a "linear polymer"), a polymer having a multi-branched structure (hereinafter also referred to as a "branched polymer"), or a mixture thereof.

[0015] Furthermore, in terms of suppressing heat generation when used in belt applications, for example, the (A1) conjugated diene polymer preferably contains a polymer (hereinafter also referred to as a "functional group-containing polymer") having a functional group (hereinafter also referred to as a "specific functional group") containing at least one element selected from the group consisting of nitrogen, oxygen, sulfur, phosphorus, tin, and silicon.

[0016] The position of the specific functional group in the functional group-containing polymer is not particularly limited. Examples of functional group-containing polymers include polymers having a specific functional group in the molecular chain (i.e., between the ends of the molecular chain), at the ends of the molecular chain, or both. 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 initiation end, the polymerization termination end, or both the polymerization initiation end and the polymerization termination end. Furthermore, the functional group-containing polymer may have the specific functional group at some of the ends in one polymer molecule, or may have the specific functional group at all of the ends in one polymer molecule. In terms of enhancing the effect of improving fuel economy in the crosslinked product, it is preferable that the functional group-containing polymer have the specific functional group at two or more ends.

[0017] 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 pattern that characterizes the compound. Examples of the specific functional group possessed by the functional group-containing polymer include 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, a nitrogen-containing group in which one hydrogen atom of a secondary amino 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, a phosphorus-containing group in which one hydrogen atom of a secondary phosphino group is protected, a tertiary phosphino group, an epoxy group, a thioepoxy group, a hydroxyl group, an oxygen-containing group in which the hydrogen atom of a hydroxyl group is protected, a thiol group, a sulfur-containing group in which the hydrogen atom of a thiol group is protected, a nitrogen-containing heterocyclic group (for example, a group having a heterocycle such as a pyridine ring or an imide ring), a hydrocarbyloxysilyl group, a hydrocarbyloxycarbonyl group, an ether bond, a thioether bond, and the following bonding modes: [ka] etc.

[0018] The functional group-containing polymer contained in the (A1) conjugated diene polymer is preferably a reaction product (hereinafter also referred to as a "modified polymer") of a conjugated diene polymer having an active terminal with a compound having a specific functional group and a reaction site with the active terminal of the conjugated diene polymer. The compound (hereinafter also referred to as a "modifier") having a specific functional group and a reaction site with the active terminal of the conjugated diene polymer may have one or more reaction sites with the active terminal. Specific examples of the specific functional group possessed by the modifier include the same groups and bonds as the specific functional groups possessed by the functional group-containing polymer. Such modified polymers can be obtained by using a coupling agent or a terminal modifier, which will be described later, as a modifier when producing the modified polymer.

[0019] The (A1) conjugated diene polymer can be produced by a method including the following polymerization step and hydrogenation step. The (A1) conjugated diene polymer may also be produced by a method including, in addition to the polymerization step and hydrogenation step, at least one of the following reaction step and modification step. Hereinafter, the molecular structure of the (A1) conjugated diene polymer will be described together with the method for producing the (A1) conjugated diene polymer.

[0020] <Polymerization process> The polymerization step is a step in which a monomer containing a conjugated diene compound and an aromatic vinyl compound is polymerized to obtain a conjugated diene polymer having an active terminal.

[0021] 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-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. The conjugated diene compounds may be used alone or in combination of two or more.

[0022] Examples of 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, and t-butoxystyrene. Among these, one or both of styrene and α-methylstyrene are preferred as aromatic vinyl compounds. The aromatic vinyl compounds may be used alone or in combination of two or more.

[0023] The (A1) conjugated diene polymer is preferably a copolymer containing 1,3-butadiene and styrene in its monomer composition, because it has a high living property in anionic polymerization. The (A1) conjugated diene polymer has a random copolymerization portion in which structural units derived from a conjugated diene compound and structural units derived from an aromatic vinyl compound are irregularly distributed, and therefore, when an inorganic filler is blended in this composition, the dispersibility of the inorganic filler can be improved.

[0024] The proportion of structural units derived from aromatic vinyl compounds in the (A1) conjugated diene polymer is preferably more than 0% by mass and not more than 50% by mass relative to all structural units constituting the (A1) conjugated diene polymer. By setting the proportion within the above range, it is possible to obtain a crosslinked product having high strength and excellent abrasion resistance while maintaining the processability of the polymer composition. The proportion of structural units derived from aromatic vinyl compounds is more preferably 2% by mass or more, and even more preferably 5% by mass or more, relative to all structural units constituting the (A1) conjugated diene polymer. Furthermore, the proportion of structural units derived from aromatic vinyl compounds is more preferably 45% by mass or less, and even more preferably 40% by mass or less, relative to all structural units constituting the (A1) conjugated diene polymer. The content of structural units derived from aromatic vinyl compounds in the polymer is 1 The values ​​were measured by H-NMR.

[0025] The conjugated diene polymer (A1) may have, together with the random copolymerization portion, a chain portion of structural units derived from a conjugated diene compound formed by randomly copolymerizing a conjugated diene compound with an aromatic vinyl compound and then adding a conjugated diene compound, although the conjugated diene polymer (A1) may not have a block of structural units derived from an aromatic vinyl compound.

[0026] Here, in this specification, the statement that the conjugated diene polymer (A1) "does not have blocks composed of structural units derived from aromatic vinyl compounds" does not exclude the conjugated diene polymer (A1) having a chain portion of structural units derived from aromatic vinyl compounds formed by, for example, adding an aromatic vinyl compound to a reactor, as long as it does not impair the effects of the present disclosure. Specifically, it is preferred that 99% by mass or more of the structural units derived from aromatic vinyl compounds contained in the conjugated diene polymer (A1) constitute random copolymerization moieties. Furthermore, it is preferred that 90% by mass or more of the total amount of structural units derived from conjugated diene compounds contained in the conjugated diene polymer (A1) constitute random copolymerization moieties, and it is preferred that 92% by mass or more constitute random copolymerization moieties.

[0027] The monomers used in the polymerization reaction to obtain the (A1) conjugated diene polymer may contain compounds other than conjugated diene compounds and aromatic vinyl compounds (hereinafter also referred to as "other monomers"). 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, and more preferably 5% by mass or less, of the total amount of monomers used in the polymerization.

[0028] The polymerization method used may be any of solution polymerization, gas phase polymerization, and bulk polymerization. Of these, solution polymerization is particularly preferred. Furthermore, the polymerization may be carried out in either a batch or continuous manner. When using solution polymerization, a specific example of the polymerization method is a method in which a monomer containing a conjugated diene compound and an aromatic vinyl compound is polymerized in an organic solvent in the presence of a polymerization initiator and, if necessary, a vinyl content adjuster (hereinafter also referred to as a "randomizer").

[0029] As the polymerization initiator, a metal compound containing an alkali metal or alkaline earth metal can be used. Among these, compounds containing an alkali metal are preferred. Specific examples of metal compounds include alkyllithium such as methyllithium, ethyllithium, n-propyllithium, n-butyllithium, sec-butyllithium, and t-butyllithium; 1,4-dilithiobutane, phenyllithium, stilbenelithium, naphthyllithium, 1,3-bis(1-lithio-1,3-dimethylpentyl)benzene, 1,3-phenylenebis(3-methyl-1-phenylpentylidene)dilithium, naphthylsodium, naphthylpotassium, and ethoxypotassium. Among these, lithium compounds are preferred.

[0030] The randomizer can be used for the purpose of adjusting the vinyl bond content, which represents the content of vinyl bonds in a polymer. Examples of the randomizer include dimethoxybenzene, tetrahydrofuran, dimethoxyethane, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, 2,2-di(tetrahydrofuryl)propane, 2-(2-ethoxyethoxy)-2-methylpropane, triethylamine, pyridine, N-methylmorpholine, tetramethylethylenediamine, and potassium dodecylbenzenesulfonate. The randomizer can be used alone or in combination of two or more.

[0031] As the organic solvent used for polymerization, an organic solvent inert to the polymerization reaction can be preferably used. Specific examples of the organic solvent used for polymerization include linear or cyclic aliphatic hydrocarbons and aromatic hydrocarbons. Among these, hydrocarbons having 3 to 8 carbon atoms are preferred, and specific examples thereof include propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, cyclohexane, propene, 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, etc. The organic solvent can be used alone or in combination of two or more.

[0032] When solution polymerization is performed, the monomer concentration in the reaction solvent is preferably 5 to 50% by mass, more preferably 10 to 30% by mass, from the viewpoint of maintaining a balance between productivity and ease of polymerization control. The temperature of the polymerization reaction is preferably -20°C to 150°C, more preferably 0 to 120°C. The polymerization reaction is preferably carried out under a pressure sufficient to maintain the monomers substantially in a liquid phase. Such a pressure can be obtained by, for example, pressurizing the reactor with a gas inert to the polymerization reaction. A conjugated diene polymer having an active terminal can be obtained by such a polymerization reaction.

[0033] In the conjugated diene polymer obtained by the above polymerization, the vinyl bond content in the structural units derived from 1,3-butadiene is preferably 15 to 85 mol %. By setting the vinyl bond content to 15 mol % or more, the flexibility of the obtained crosslinked product is maintained and the processability is good. In addition, the abrasion resistance in the low slip range tends to be excellent. The vinyl bond content is preferably 20 mol % or more, more preferably 25 mol % or more. 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, the "vinyl bond content" is a value indicating the content ratio of structural units having 1,2-bonds to all structural units derived from 1,3-butadiene contained in the conjugated diene polymer before hydrogenation. The vinyl bond content is 1 It is measured by H-NMR equipment.

[0034] <Denaturation process> The conjugated diene polymer obtained in the polymerization step or the reaction step may be directly subjected to the subsequent hydrogenation step. Furthermore, the conjugated diene polymer obtained in the polymerization step or the reaction step may be subjected to a treatment, prior to the hydrogenation step, in which the active terminals of the conjugated diene polymer are reacted with a compound having a specific functional group and capable of reacting with the active terminals of the conjugated diene polymer. By carrying out such a treatment, when the conjugated diene polymer obtained in the polymerization step or the reaction step contains a polymer having an active terminal, it is possible to incorporate into the conjugated diene polymer (A1) a polymer in which the molecular chain of the linear conjugated diene polymer is bonded to a terminal-modifying agent (i.e., having a specific functional group). The terminal-modifying agent preferably has 1 to 8 reactive sites with the active terminals of the conjugated diene polymer.

[0035] A preferred specific example of the terminal modifying agent is at least one selected from the group consisting of compounds represented by the following formula (5) and compounds represented by the following formula (6). [ka] (In formula (5), A 11has at least one element selected from the group consisting of nitrogen, phosphorus, oxygen, sulfur, and silicon, does not have active hydrogen, and R 35 R is a monovalent functional group bonded to R at a carbon atom contained in a nitrogen, phosphorus, oxygen, sulfur, silicon, or carbonyl group, or is a (thio)epoxy group. 33 and R 34 are each independently a hydrocarbyl group. 35 is a hydrocarbylene group, and t is an integer of 0 to 2. However, when t is 2, multiple R 33 are the same or different. When t is 0 or 1, multiple R 34 are the same or different from each other.) [ka] (In formula (6), A 12 has at least one element selected from the group consisting of nitrogen, phosphorus, oxygen, sulfur, and silicon, does not have active hydrogen, and R 39 R is a monovalent functional group bonded to R via nitrogen, phosphorus, oxygen, sulfur, or silicon, or a hydrocarbyl group having 1 to 20 carbon atoms. 36 and R 37 are each independently a hydrocarbyl group. 38 is a hydrocarbylene group. 39 is a single bond or a hydrocarbylene group. u is 0 or 1. However, when u is 0, multiple R 37 are the same or different from each other.)

[0036] In the above formulas (5) and (6), R 33 , R 34 , R 36 , R 37 and A when it is a hydrocarbyl group. 12 With regard to the above, the hydrocarbyl group is preferably a linear or branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms. R 38 and R 39The hydrocarbylene group represented by the formula (I) is preferably a linear or branched alkanediyl group having 1 to 20 carbon atoms, a cycloalkylene group having 3 to 20 carbon atoms, or an arylene group having 6 to 20 carbon atoms. 38 The hydrocarbylene group represented by the following formula is preferably a linear or branched alkanediyl group having 1 to 20 carbon atoms. t is preferably 0 or 1.

[0037] A 11 When A is the monovalent functional group, 11 at least one element selected from the group consisting of nitrogen, phosphorus, oxygen, sulfur and silicon, and 12 When A is the monovalent functional group, 12 At least one element selected from the group consisting of nitrogen, phosphorus, oxygen, sulfur, and silicon may be protected, for example, by a tri-substituted hydrocarbylsilyl group. In this specification, active hydrogen refers to a hydrogen atom bonded to an atom other than a carbon atom, and preferably refers to one having a bond energy lower than that of the carbon-hydrogen bond of polymethylene. The term "(thio)epoxy group" encompasses both epoxy and thioepoxy groups.

[0038] Specific examples of the terminal modifying agent include compounds represented by formula (5), such as N,N-bis(trimethylsilyl)aminopropyltrimethoxysilane, N,N-dimethylaminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane, N,N',N'-tris(trimethylsilyl)-N-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-(4-trimethylsilyl-1-piperazino)propylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropyltriethoxysilane.

[0039] Specific examples of the compound represented by formula (6) include 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1,2-azasilolidine, 2,2-diethoxy-1-(3-trimethoxysilylpropyl)-1,2-azasilolidine, 2,2-dimethoxy-1-phenyl-1,2-azasilolidine, 1-trimethylsilyl-2,2-dimethoxy-1-aza-2-silacyclopentane, 2-(2,2-dimethoxy-1,2-azasilolidine-1-yl)-N,N-diethylethan-1-amine, 2-(2,2-dimethoxy-1,2-azasilolidine-1-yl)-N,N-dimethylethan-1-amine, and 3-(2,2-dimethoxy-1,2-azasilolidine-1-yl)-N,N-diethylpropan-1-amine. The terminal modifying agent may be used alone or in combination of two or more.

[0040] The reaction between the conjugated diene polymer having an active terminal and the terminal-modifying agent can be carried out, for example, as a solution reaction. This solution reaction may be carried out using either a batch system or a continuous system. In this case, the method of adding the terminal-modifying agent is not particularly limited, and examples thereof include a method of adding the terminal-modifying agent all at once, a method of adding the terminal-modifying agent in portions, and a method of adding the terminal-modifying agent continuously.

[0041] The amount of the terminal modifier used can be appropriately set depending on the type of compound used in the reaction. The amount of the terminal modifier is preferably 0.05 mol or more, more preferably 0.1 mol or more, per mol of metal atoms involved in the polymerization reaction of the polymerization initiator. By using an amount of the terminal modifier of 0.1 molar equivalents or more, the modification reaction can be sufficiently promoted, and the effect of improving the dispersibility of the inorganic filler can be enhanced. Furthermore, the amount of the terminal modifier is preferably 1.0 mol or less, more preferably 0.8 mol or less, per mol of metal atoms involved in the polymerization reaction of the polymerization initiator.

[0042] In the modification reaction using a terminal modifying agent, the reaction temperature is usually the same as the polymerization reaction temperature, and is preferably -20 to 150°C, more preferably 0 to 120°C, and even more preferably 20 to 100°C. If the modification reaction temperature is low, the viscosity of the polymer solution tends to increase. Furthermore, if the modification reaction temperature is high, the polymerization active terminals are likely to be deactivated. The reaction time for terminal modification is preferably 1 minute to 5 hours, and more preferably 2 minutes to 1 hour.

[0043] In addition, when the conjugated diene polymer having an active end obtained by the polymerization step is not subjected to either the reaction step or the modification step, the conjugated diene polymer having an active end may be reacted with a polymerization terminator such as an alcohol, and then the subsequent hydrogenation step may be carried out. In this case, it is preferable to use an initiation end-modifying agent in the polymerization step to obtain a conjugated diene polymer having a specific functional group.

[0044] <Hydrogenation process> In the hydrogenation step, the conjugated diene polymer obtained in the 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 is obtained. Examples of such hydrogenation methods include a method using a catalyst containing an organometallic compound of titanium as the main component as a hydrogenation catalyst; a method using a catalyst composed of an organometallic compound of iron, nickel, or cobalt and an organometallic compound such as alkylaluminum; a method using an organic complex of an organometallic compound such as ruthenium or rhodium; and a method using a catalyst in which a metal such as palladium, platinum, ruthenium, cobalt, or nickel is supported on a support such as carbon, silica, or alumina. Among the various methods, a method in which hydrogenation is carried out under mild conditions of low pressure and low temperature using a homogeneous catalyst composed of a titanium organometallic compound alone or a titanium organometallic compound together with an organometallic compound of lithium, magnesium or aluminum (for example, the catalysts described in Japanese Patent Publication Nos. 63-4841 and 1-37970) is industrially preferred, and is also suitable because of its high hydrogenation selectivity to the double bond of butadiene.

[0045] The hydrogenation of a conjugated diene polymer is preferably carried out using a solvent that is inert to the catalyst and that dissolves the conjugated diene polymer. 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 ethers such as diethyl ether and tetrahydrofuran. The solvent used for hydrogenation may be one of the above compounds or a mixture containing them as the main component.

[0046] The hydrogenation reaction is generally carried out by maintaining the conjugated diene polymer at a predetermined temperature in a hydrogen or inert atmosphere, adding a hydrogenation catalyst with or without stirring, and then introducing hydrogen gas to pressurize to a predetermined pressure. An inert atmosphere refers to an atmosphere that does not react with the substances involved in the hydrogenation reaction, and examples include helium, neon, and argon. Air and oxygen are undesirable because they oxidize the catalyst and cause catalyst deactivation. Nitrogen is also undesirable because it acts as a catalyst poison during the hydrogenation reaction and reduces hydrogenation activity. In particular, it is most suitable for the hydrogenation reactor to have an atmosphere of hydrogen gas alone.

[0047] The hydrogenation reaction process can be any of a batch process, a continuous process, and a combination thereof. When a titanocene diaryl compound is used as the hydrogenation catalyst, it may be added to the reaction solution either as is or as a solution in an inert organic solvent. When the catalyst is used as a solution, the inert organic solvent used can be any solvent that does not react with the substances involved in the hydrogenation reaction. The inert organic solvent is preferably the same solvent as that used in the hydrogenation reaction. The preferred amount of catalyst added is 0.02 to 20 mmol per 100 g of the conjugated diene polymer before hydrogenation.

[0048] In the (A1) conjugated diene polymer, when the constituent ratios (molar ratios) of the structural unit represented by the above formula (1), the structural unit represented by the formula (2), the structural unit represented by the formula (3), and the structural unit represented by the formula (4) in the polymer are p, q, r, and s, respectively, the value α represented by the mathematical formula (i) is 0.50 or more and 0.98 or less. α=(p+(0.5×r)) / (p+q+(0.5×r)+s) …(i)

[0049] If the α value of the (A1) conjugated diene polymer is less than 0.50, the (A1) conjugated diene polymer has a high unsaturated bond content, resulting in a large change in Mooney viscosity due to differences in desolvation time. This can lead to instability in the quality of the (A1) conjugated diene polymer or increased heat accumulation and combustibility of the (A1) conjugated diene polymer adhering to equipment. Furthermore, the instability in the quality of the (A1) conjugated diene polymer can lead to a decrease in the strength and viscoelastic properties of the crosslinked product. If the α value of the (A1) conjugated diene polymer is greater than 0.98, crosslinking cannot proceed sufficiently, and the strength and viscoelastic properties of the crosslinked product tend to decrease. From this perspective, the α value of the (A1) conjugated diene polymer is preferably 0.55 or greater, more preferably 0.60 or greater, and particularly preferably 0.65 or greater. When 20% by mass or more of other components, such as the (A2) component described below, are used in combination as the rubber component, α is preferably 0.60 or greater. The value α of the conjugated diene polymer (A1) is more preferably 0.97 or less, and even more preferably 0.95 or less.

[0050] The value α represented by the mathematical 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 of the conjugated diene polymer and the value α can be adjusted by adjusting the hydrogenation reaction time or controlling the cumulative amount of hydrogen supplied. In this specification, the hydrogenation rate is 1These are values ​​measured by a H-NMR apparatus. Regarding p, q, r, and s in formula (i), when the constituent ratios of the structural units of formulas (1) to (4) in the polymer are expressed in mole percent, p, q, r, and s can each take a value of 0 to 100% (with the proviso that the total value of p, q, r, and s is 100% or less).

[0051] A preferred method for obtaining the (A1) conjugated diene polymer is to solution polymerize a monomer containing 1,3-butadiene and styrene in the presence of a polymerization initiator (preferably a metal amide compound), add a coupling agent to the resulting polymer solution to carry out a coupling reaction, add a terminal modifier as needed, and then subject the polymer to a hydrogenation step. This method is preferred because it can obtain a crosslinked product excellent in various physical properties (strength, viscoelasticity, etc.), and is also industrially useful.

[0052] The weight average molecular weight (Mw) of the (A1) conjugated diene polymer, measured using gel permeation chromatography (GPC) in terms of polystyrene, is preferably 1.5 × 10, from the viewpoint of obtaining a crosslinked product having high strength and excellent abrasion resistance. 5 ~2.0×10 6 The Mw of the conjugated diene polymer is more preferably 1.8 × 10 5 More preferably, it is 2.0×10 5 More preferably, Mw is 1.6×10 or more. 6 or less, more preferably 1.4 × 10 6 The weight average molecular weight of the conjugated diene polymer referred to here is a value determined from all peaks of a GPC curve measured by GPC before hydrogenation. Hereinafter, it is also referred to as "total average molecular weight."

[0053] Furthermore, the molecular weight distribution (ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (weight average molecular weight / number average molecular weight)) of the total amount of the polymer (i.e., an aggregate of different molecular weights) measured by GPC for the conjugated diene polymer (A1) is preferably 1.1 or more and 4.0 or less. A molecular weight distribution of 1.1 or more is preferred in terms of excellent processability, and a molecular weight distribution of 4.0 or less is preferred in terms of sufficiently improving the low hysteresis loss of the resulting crosslinked product. The molecular weight distribution of the conjugated diene polymer (A1) is more preferably 1.2 or more. The molecular weight distribution of the conjugated diene polymer (A1) is more preferably 3.5 or less, and even more preferably 3.0 or less.

[0054] The proportion of the modified polymer in the (A1) conjugated diene polymer is preferably 10% by mass or more relative to the total amount of the (A1) conjugated diene polymer. When the proportion of the modified polymer in the (A1) conjugated diene polymer is within the above range, the strength and viscoelastic properties of the resulting crosslinked product can be improved. The proportion of the modified polymer in the (A1) conjugated diene polymer is more preferably 15% by mass or more, and even more preferably 20% by mass or more. The proportion (mass%) of the modified polymer in the (A1) conjugated diene polymer is a value calculated by adding the proportion of linear polymers having a partial structure derived from the terminal modifier and the coupling rate. The reactivity of the terminal modifier in the reaction between the conjugated diene polymer having an active terminal and the terminal modifier can be calculated by subjecting the polymer solution after the modification reaction with the terminal modifier to gas chromatography and quantifying the amount of unreacted terminal modifier.

[0055] Component (A2): Second rubber component The present composition may contain only the conjugated diene polymer (A1) as the rubber component, or may contain, in addition to the conjugated diene polymer (A1), a second rubber component (hereinafter also referred to as "component (A2)") different from the conjugated diene polymer (A1). Examples of component (A2) include natural rubber, isoprene rubber, butadiene rubber, emulsion-polymerized or solution-polymerized styrene-butadiene rubber, chloroprene rubber, and ethylene-propylene rubber. These components (A2) may be used alone or in combination of two or more. Commercially available products can be used as component (A2).

[0056] The blending amount of the (A2) component is preferably 20% by mass or more and 80% by mass or less, and more preferably 25% by mass or more and 75% by mass or less, based on the total amount of rubber components contained in the polymer composition. By blending the (A2) component in the above range, it is possible to achieve both strength and abrasion resistance.

[0057] (A3) Component: Other rubber components The present composition may contain only the (A1) conjugated diene polymer and the (A2) component as rubber components, but may also contain a rubber component (hereinafter also referred to as "(A3) component") different from the (A1) conjugated diene polymer and the (A2) second rubber component within a range that does not impair the effects of the present invention. As the (A3) component, for example, at least one rubber selected from butyl rubber, halogenated butyl rubber, acrylic rubber, etc. can be used.

[0058] The blending amount of the component (A3) is preferably 20% by mass or less, and more preferably 10% by mass or less, based on the total amount of rubber components contained in the polymer composition.

[0059] (B) Component: Carbon black The composition contains carbon black from the viewpoint of the fracture properties and abrasion resistance of the polymer composition. The carbon black is not particularly limited, and examples thereof include GPF, FEF, HAF, ISAF, and SAF grade carbon black. The nitrogen adsorption specific surface area (N2SA) of the carbon black is not particularly limited, and is preferably 50 to 200 m 2 / g is preferred, and 70 to 150m 2 / g is more preferable. The nitrogen adsorption specific surface area (N2SA) is the value obtained by measuring the amount of nitrogen adsorbed onto the surface of carbon black according to JIS K6217-2:2001 "Part 2: Determination of specific surface area - Nitrogen adsorption method - Single point method." 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 composition is 25 parts by mass or more, preferably 30 parts by mass or more, more preferably 35 parts by mass or more, and particularly preferably 40 parts by mass or more, per 100 parts by mass of the (A) rubber component. The amount of carbon black is 150 parts by mass or less, preferably 120 parts by mass or less, and more preferably 100 parts by mass or less.

[0060] (C) Component: Inorganic filler other than carbon black The present composition contains carbon black as an inorganic filler, but may also contain an inorganic filler other than carbon black (hereinafter also referred to as "component (C)").

[0061] (C1) component: silica The composition may contain silica. The amount of silica blended is preferably 80 parts by mass or less, and more preferably 60 parts by mass or less, per 100 parts by mass of the (A) rubber component. Blending silica can sufficiently improve the processability of the polymer composition.

[0062] The silica is not particularly limited, and examples thereof include wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), calcium silicate, and aluminum silicate. Among these, wet silica is preferred. As the silica, one type may be used alone, or two or more types may be used in combination.

[0063] (C2) Ingredient: Other fillers The composition may contain, as an inorganic filler, other fillers in addition to carbon black and silica, such as talc, clay, and metal oxide particles represented by the following formula (7): mM xSiO y zH2O (7) (In the formula, M is at least one metal selected from the group consisting of aluminum, magnesium, titanium, calcium, and zirconium, an oxide or hydroxide of such a metal, a hydrate thereof, or a carbonate of such a metal; and m, x, y, and z are integers of 1 to 5, 0 to 10, 2 to 5, and 0 to 10, respectively. In the above formula, when x and z are both 0, the inorganic compound is at least one metal, metal oxide, or metal hydroxide selected from aluminum, magnesium, titanium, calcium, and zirconium.)

[0064] Specific examples of metal oxides represented by formula (7) include alumina (Al2O3) such as γ-alumina and α-alumina, alumina monohydrate (Al2O3·H2O) such as boehmite and diaspore, aluminum hydroxide [Al(OH)3] such as gibbsite and bayerite, aluminum carbonate [Al2(CO3)3], magnesium hydroxide [Mg(OH)2], magnesium oxide (MgO), magnesium carbonate (MgCO3), talc (3MgO·4SiO2·H2O), attapulgite (5MgO·8SiO2·9H2O), titanium(IV) oxide (TiO2), titanium(II) oxide (TiO 2n-1), calcium oxide (CaO), calcium hydroxide [Ca(OH)2], magnesium aluminum oxide (MgO·Al2O3), clay (Al2O3·2SiO2), kaolin (Al2O3·2SiO2·2H2O), pyrophyllite (Al2O3·4SiO2·H2O), bentonite (Al2O3·4SiO2·2H2O), aluminum silicates (Al2SiO5, Al4·3SiO4·5H2O, etc.), magnesium silicates (Mg2SiO4, MgSiO3, etc.) , calcium silicate (Ca2SiO4, etc.), calcium aluminum silicate (Al2O3·CaO·2SiO2, etc.), calcium magnesium silicate (CaMgSiO4), calcium carbonate (CaCO3), zirconium oxide (ZrO2), zirconium hydroxide [ZrO(OH)2·nH2O], zirconium carbonate [Zr(CO3)2], and crystalline aluminosilicates containing hydrogen, alkali metals, or alkaline earth metals to compensate for the charge, such as various zeolites.

[0065] In the present composition, the blending amount of the (C) component is preferably 150 parts by mass or less, and more preferably 130 parts by mass or less, per 100 parts by mass of the (A) rubber component. When the blending amount of the inorganic filler in the present composition is within the above range, a good balance between strength and processability can be achieved.

[0066] Component (D): Crosslinking agent The present composition may contain a crosslinking agent. By including the crosslinking agent in the present composition, a crosslinked product with improved strength and abrasion resistance can be obtained. Examples of crosslinking agents include sulfur, sulfur halides, organic peroxides, quinone dioximes, organic polyamine compounds, and alkylphenol resins having methylol groups, with sulfur being typically used. The amount of crosslinking agent blended is preferably 0.1 to 5 parts by mass, more preferably 0.5 to 3 parts by mass, per 100 parts by mass of the total amount of rubber components contained in the present composition.

[0067] ·(E) Component: Extender oil The composition may contain a process oil commonly used to extend elastomers as an oil for oil extension (extender oil). The method for adding the process oil is not particularly limited. For example, the process oil may be dispersed in a conjugated diene polymer solution after polymerization and then desolvated to form an oil-extended rubber. Alternatively, the process oil may be directly added to the polymer composition during kneading to obtain a rubber compound (compounded rubber). Suitable process oils include various oils known in the art, such as aromatic oils, paraffinic oils, naphthenic oils, vegetable oils, and oils with a low content of polycyclic aromatic compounds (low PCA oils), such as mild extraction solvates (MES), treated distillate aromatic extracts (TDAE), special residual aromatic extracts (SRAE), and heavy naphthenic oils. Examples of commercially available MES, TDAE, and SRAE include Catenex SNR (heavy paraffin obtained by dewaxing distillate oil with a solvent) manufactured by Shell as MES, Vivatec 500 manufactured by H&R Wasag AG as TDAE, and NC140 manufactured by Japan Energy Corp. The amount of process oil blended is preferably 10 to 100 parts by mass per 100 parts by mass of the total amount of polymer components contained in the polymer composition.

[0068] <Other ingredients> In addition to the components described above, the composition may contain various additives commonly used in polymer compositions for obtaining vulcanized rubber, such as zinc oxide, stearic acid, softeners, vulcanization accelerators, antioxidants, silane coupling agents, compatibilizers, vulcanization aids, processing aids, and scorch inhibitors. The blending ratios of these additives may be appropriately selected depending on the various components, as long as the effects of the present disclosure are not impaired.

[0069] <<Method for producing polymer composition>> The present composition can be obtained by mixing (A) the rubber component and (B) the carbon black. The manner in which the present composition is obtained by mixing (A) the rubber component and (B) the carbon black is not particularly limited.

[0070] A blended composition (hereinafter also referred to as "polymer composition Q") can be obtained as another embodiment of the present composition by blending (A) rubber component, (B) carbon black, and, if necessary, the various components described above (components (C) to (E), etc.). The blended composition can be obtained by mixing polymer composition P with various additives optionally used in polymer compositions for obtaining vulcanized rubber, and kneading the mixture preferably using a kneader such as an open kneader (e.g., a roll) or an internal kneader (e.g., a Banbury mixer). The blended rubber thus obtained is molded and then crosslinked (vulcanized) to obtain a crosslinked product (i.e., vulcanized rubber).

[0071] The conveyor belt, power transmission belt, electric wire covering material, and rubber roller of the present invention are not particularly limited in their manufacturing method, and can be manufactured by known manufacturing methods. For example, the conveyor belt or power transmission belt can be produced by kneading a rubber composition for the cover rubber layer using a Banbury mixer, a kneader mixer, an open roll, or the like, and then forming the rubber composition into a sheet using a calendar or the like to prepare an unvulcanized sheet for the rubber layer, and then vulcanizing and integrating the unvulcanized sheet with a core material having adhesive rubber carried on its surface. The wire covering material can be produced, for example, by molding and vulcanizing the kneaded rubber composition using an extruder so as to uniformly cover the surface of the core wire. The roller can be manufactured by forming it by winding up a calendared rubber sheet, by molding it into a cylindrical shape using an extruder, or by filling a mold with a rubber composition and molding it using a press, and then heating it to crosslink it.

[0072] As described above, one embodiment has been shown as an example, but the polymer composition and uses according to the present invention are not limited to the configuration of the above embodiment. The polymer composition according to the present invention can be modified in various ways without departing from the gist of the present invention.

[0073] According to the present disclosure described above, the following means are provided. [Measure 1] (A) a rubber component, and (B) carbon black Contains The (A) rubber component contains (A1) a conjugated diene polymer in which the value α represented by the following formula (i) is 0.60 to 0.98 when the constituent ratios (molar ratios) in the polymer of the structural unit represented by the following formula (1), the structural unit represented by the following formula (2), the structural unit represented by the following formula (3), and the structural unit represented by the following formula (4) are p, q, r, and s, respectively: The (A) rubber component contains 20 to 80 mass% of (A2) one or more components selected from the group consisting of natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, and ethylene-α-olefin copolymer, A polymer composition comprising 25 to 150 parts by mass of (B) carbon black per 100 parts by mass of (A) the rubber component. α=(p+(0.5×r)) / (p+q+(0.5×r)+s) …(i) [ka] [Measure 2] The polymer composition according to the first aspect, comprising, as the component (A1), a polymer having a functional group containing at least one element selected from the group consisting of nitrogen, oxygen, sulfur, phosphorus, tin, and silicon. [Measure 3] 3. The polymer composition according to Measure 1 or 2, wherein the proportion of the component (A1) is 10 to 100% by mass based on the total amount of the component (A). [Measure 4] 4. The polymer composition according to any one of means 1 to 3, wherein the proportion of the component (A1) is 20 to 70% by mass based on the total amount of the component (A). [Measure 5] The polymer composition according to any one of means 1 to 4, wherein the (A) rubber component contains (A2) one or more components selected from the group consisting of natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, and ethylene-α-olefin copolymer. [Measure 6] The polymer composition according to any one of means 1 to 5, wherein the component (A1) is a polymer having a random copolymerization portion of a structural unit derived from a conjugated diene compound and a structural unit derived from an aromatic vinyl compound, and not having a block consisting of a structural unit derived from an aromatic vinyl compound. [Means 7] The polymer composition according to any one of the first to sixth means, further comprising a crosslinking agent. [Means 8] A crosslinked product obtained by curing the polymer composition according to Measure 7. [Means 9] (A) a rubber component, and (B) carbon black Contains The (A) rubber component contains (A1) a conjugated diene polymer in which the value α represented by the following formula (i) is 0.50 to 0.98 when the constituent ratios (molar ratios) in the polymer of the structural unit represented by the following formula (1), the structural unit represented by the following formula (2), the structural unit represented by the following formula (3), and the structural unit represented by the following formula (4) are respectively p, q, r, and s: The (A) rubber component contains 80% by mass or more of the (A1) conjugated diene polymer when the (A) rubber component is 100% by mass, The polymer composition for industrial belts contains 25 to 150 parts by mass of (B) carbon black per 100 parts by mass of the (A) rubber component. α=(p+(0.5×r)) / (p+q+(0.5×r)+s) …(i) [ka] [Measure 10] 10. The polymer composition according to Item 9, further comprising a crosslinking agent. [Means 11] A crosslinked product obtained by curing the polymer composition according to Measure 10. [Means 12] An industrial belt, at least part of which uses the crosslinked body according to Measure 8 or Measure 11. [Means 13] A roll using the crosslinked product according to Measure 8 or Measure 11 as at least a part thereof. [Means 14] 12. A wire covering material comprising the crosslinked product according to Measure 8 or Measure 11. [Example]

[0074] The present disclosure will be specifically explained below based on examples, but the present disclosure is not limited to these examples. In the examples and comparative examples, "parts" and "%" are by mass unless otherwise specified. The methods for measuring various physical properties of the polymer are shown below.

[0075] [Polymer Characterization] Bound styrene content (%): For the polymer before hydrogenation, 400MHz 1 Measurement was performed using a H-NMR device. Hydrogenation rate (%) and α: Measured using ethylene tetrachloride as a solvent with a 100MHz device 1 Calculated from H-NMR spectrum.

[0076] <Production of hydrogenated conjugated diene polymer> [Production Example 1: Production of Hydrogenated Conjugated Diene Polymer A-1 and Its Properties] A 50-liter autoclave reactor with a nitrogen-purged interior was charged with 25,800 g of cyclohexane, 72 g of tetrahydrofuran, 430 g of styrene, and 3,741 g of 1,3-butadiene. The temperature of the reactor contents was adjusted to 40°C, and a cyclohexane solution containing n-butyllithium (40 mmol) was added to initiate polymerization. The polymerization was carried out under adiabatic conditions. After confirming that the polymerization conversion rate had reached 99%, 129 g of 1,3-butadiene was added (additional butadiene) and polymerization was continued for an additional 3 minutes to obtain a reaction solution containing a polymer. 2 mmol of silicon tetrachloride was added to the resulting reaction solution and reacted for 5 minutes, followed by the addition of 27 mmol of [N,N-bis(trimethylsilyl)aminopropyl]methyldiethoxysilane and the reaction for 15 minutes. Next, the reaction solution was heated to 80°C or higher, hydrogen was introduced into the system, and the reaction was carried out for 1 hour. A small amount of the polymer solution was withdrawn from the reaction vessel and used for analysis to obtain a pre-hydrogenated conjugated diene polymer. Subsequently, 31 mmol of diethylaluminum chloride, 12 mmol of bis(η5-cyclopentadienyl)titanium(furfuryloxy)chloride, and 27 mmol of n-butyllithium were added, and the hydrogenation reaction was carried out while maintaining a hydrogen pressure of 1.0 MPa. After the reaction, hydrogen was supplied until a predetermined hydrogen accumulation value was reached while maintaining a hydrogen pressure of 0.7 MPa or higher. The reaction solution was then returned to room temperature and pressure and withdrawn from the reaction vessel to obtain a polymer solution containing hydrogenated conjugated diene polymer P1. A small amount of the obtained polymer solution was withdrawn, the solvent was removed by steam stripping, and the solution was dried using a heated roll adjusted to 130°C to obtain hydrogenated conjugated diene polymer A1-1. The hydrogenated conjugated diene polymer P1 had a bound styrene content of 10 mass % and a hydrogenation rate of 55% (α=0.55).

[0077] [Manufacturing Examples 2 to 6] Hydrogenated conjugated diene polymer A1-2 with a hydrogenation rate of 70% and hydrogenated conjugated diene polymer A1-3 with a hydrogenation rate of 95% were obtained by performing the same operation as in Production Example 1, except that the amount of hydrogen supplied was changed. Similarly, by changing the amounts of styrene and butadiene charged and the integrated hydrogen value of the hydrogenation reaction, hydrogenated conjugated diene polymer A1-4 with a bound styrene content of 40% by mass and a hydrogenation rate of 60%, hydrogenated conjugated diene polymer A1-5 with a bound styrene content of 40% by mass and a hydrogenation rate of 90%, and hydrogenated conjugated diene polymer A1-6 with a bound styrene content of 25% by mass and a hydrogenation rate of 90% were obtained, respectively.

[0078] <Production of polymer composition and crosslinked product> [Example 1] Production of polymer composition P In the first stage of mixing, a plastomill (capacity: 250 cc) equipped with a temperature control device was used to mix (A) the rubber component, (B) carbon black, a softener, zinc oxide, stearic acid, and an antioxidant according to the formulations shown in Tables 1 to 3 at a filling rate of 72% and a rotation speed of 60 rpm. In the second stage of mixing, the mixture obtained above was cooled to room temperature, and then sulfur and a vulcanization accelerator were added and mixed. The mixture was molded and vulcanized in a vulcanization press at 160°C for a predetermined time to obtain a crosslinked product. The resulting crosslinked product was evaluated for the following properties. The results are shown in Tables 1 to 3. The types and proportions of each component used in each example and comparative example are as shown in Tables 1 to 3. The values ​​in the tables indicate the proportion (parts by mass) of each component.

[0079] The materials used in the examples are as follows: EPDM: ENEOS Materials, product name "EP33" NR:RSS#3 BR: Manufactured by ENEOS Materials, product name "BR01" SBR: ENEOS Materials, product name "ESBR1502" CR: Denka Co., Ltd., product name "PN-40NS" Carbon black: Cabot Corporation, product name "Showblack N550" Silica: Tosoh Silica Corporation, product name "Nipsil VN3" Silane coupling agent: Evonik, product name "Si75" Softener: Naphthenic oil Anti-aging agent: Ouchi Shinko Chemical Industry Co., Ltd., product name "Nocrac 6C" Magnesium oxide: Kyowa Chemical Industry Co., Ltd., product name "Kyowamag MF-150" Vulcanization accelerator-1: Ouchi Shinko Chemical Industry Co., Ltd., product name "Noccela CZ" Vulcanization accelerator-2: Ouchi Shinko Chemical Industry Co., Ltd., product name "Noccela D" Vulcanization accelerator-3: Sansera 22, manufactured by Sanshin Chemical Industry Co., Ltd. Peroxide: NOF Corporation, product name "Perkmyl D-40"

[0080] <Strength> The tensile strength (Tb) was measured using a tensile testing device according to JIS K 6251:2017, where a polymer molded body was stretched at 25°C and the maximum tensile force required to break was used. The elongation at break (Eb) was determined by pulling the polymer molded body at a rate of 100 mm / min at 25°C, measuring the length at which the polymer molded body broke, and calculating the length relative to the length before pulling (100%). The strength of the crosslinked body was expressed as an index, where the product of the tensile strength and the elongation at break is set to 100 for Comparative Example 1, with a larger index indicating better strength.

[0081] <Wear resistance> DIN abrasion was measured based on JIS K 6264-2: 2005. The results are expressed as an index with Comparative Example 1 being set at 100, with a larger index indicating better abrasion resistance.

[0082] <Heat resistance> In accordance with JIS K 6257:2017, the crosslinked material was left to stand in a Geer oven at 160°C for 7 days to age, and the retention of breaking elongation (breaking elongation after aging relative to the initial breaking elongation) was measured. The rate of change in elongation was evaluated according to the following criteria. A: Less than 20% B: 20% or more but less than 50% C: 50% or more

[0083] <Ozone resistance> JIS No. 3 dumbbell-shaped test pieces conforming to JIS K6251 were cut out from each crosslinked sheet, and each test piece was stretched by 30% and subjected to ozone degradation for 72 hours under conditions of an ozone concentration of 100 pphm and 50°C. The presence or absence of ozone cracks on the test piece surface was then evaluated according to the following criteria. 5: No cracks are visible to the naked eye or with a 10x magnifying glass 4: Cracks are not visible to the naked eye but can be seen with a 10x magnification. 3: Cracks are visible to the naked eye, deep and relatively large (less than 1 mm in length) 2: Deep and large cracks (less than 1-3 mm in length) were observed. 1: A crack of 3 mm or more in length was observed or the test piece was broken.

[0084] [Table 1]

[0085] [Table 2]

[0086] [Table 3]

[0087] From the above results, it can be seen that the crosslinked product of the present invention has excellent strength, abrasion resistance, and ozone resistance. It became clear.

Claims

1. (A) a rubber component, and (B) carbon black Contains The rubber component (A) contains (A1) a conjugated diene polymer in which the value α represented by the following formula (i) is 0.60 to 0.98, when the constituent ratios (molar ratios) in the polymer of the structural unit represented by the following formula (1), the structural unit represented by the following formula (2), the structural unit represented by the following formula (3), and the structural unit represented by the following formula (4) are respectively p, q, r, and s: The rubber component (A) contains 20 to 80 mass % of (A2) one or more components selected from the group consisting of natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, and ethylene-α-olefin copolymer, A polymer composition comprising 25 to 150 parts by mass of (B) carbon black per 100 parts by mass of the (A) rubber component. α=(p+(0.5×r)) / (p+q+(0.5×r)+s)…(i) 【Chemistry 1】

2. 2. The polymer composition according to claim 1, comprising, as the component (A1), a polymer having a functional group containing at least one element selected from the group consisting of nitrogen, oxygen, sulfur, phosphorus, tin, and silicon.

3. 2. The polymer composition according to claim 1, wherein the proportion of the component (A1) is 10 to 100% by mass based on the total amount of the component (A).

4. 2. The polymer composition according to claim 1, wherein the proportion of the component (A1) is 20 to 70 mass% based on the total amount of the component (A).

5. 2. The polymer composition according to claim 1, wherein the rubber component (A) contains one or more components selected from the group consisting of (A2) natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, and ethylene-α-olefin copolymer.

6. 2. The polymer composition according to claim 1, wherein the component (A1) is a polymer having a random copolymerization portion of a structural unit derived from a conjugated diene compound and a structural unit derived from an aromatic vinyl compound, and having no blocks composed of structural units derived from an aromatic vinyl compound.

7. The polymer composition of claim 1 further comprising a crosslinking agent.

8. A crosslinked product obtained by curing the polymer composition according to claim 7.

9. (A) a rubber component, and (B) carbon black Contains The rubber component (A) contains (A1) a conjugated diene polymer in which the value α represented by the following formula (i) is 0.50 to 0.98, when the constituent ratios (molar ratios) in the polymer of the structural unit represented by the following formula (1), the structural unit represented by the following formula (2), the structural unit represented by the following formula (3), and the structural unit represented by the following formula (4) are respectively p, q, r, and s: The rubber composition contains 80% by mass or more of the conjugated diene polymer (A1) when the rubber component (A) is 100% by mass, The polymer composition for industrial belts contains 25 to 150 parts by mass of (B) carbon black per 100 parts by mass of the (A) rubber component. α=(p+(0.5×r)) / (p+q+(0.5×r)+s)…(i) 【Chemistry 2】

10. The polymer composition for industrial belts according to claim 9, further comprising a crosslinking agent.

11. A crosslinked product obtained by curing the polymer composition according to claim 10.

12. An industrial belt, at least in part of which is made of the crosslinked product according to claim 8 or 11.

13. A roll comprising at least a portion of the crosslinked product according to claim 8.

14. A wire covering material comprising the crosslinked product according to claim 8.

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