Polymer composition and cross-linked body

Abstract

To provide a polymer composition that allows production of a hose exhibiting high oil resistance, and excellent abrasion resistance and heat resistance.SOLUTION: A polymer composition comprises: (A) a conjugated diene-based polymer, and (B) at least one polymer selected from the group consisting of nitrile rubber, hydrogenated nitrile rubber, and ethylene-vinyl acetate copolymer, wherein the rubber component (A) is a conjugated diene-based polymer having a value α, expressed by the following formula (i), in the range of 0.60 to 0.98, where the composition ratios (molar ratios) of the structural units represented by the following formulas (1), (2), (3), and (4) in the polymer are defined as p, q, r, and s respectively. Formula (i): α=(p+(0.5×r)) / (p+q+(0.5×r)+s).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] Hoses used for industrial purposes have often been used for infusing oil, and oil resistance has been an issue for some time (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-131899 Summary of the Invention [Problem to be solved by the invention]

[0004] Industrial hoses are often used in high-temperature environments, and have the problem of poor heat resistance and ozone resistance.

[0005] The present invention has been made in view of the above problems, and one object of the present invention is to provide a polymer composition from which a hose having high oil resistance, 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 conjugated diene-based 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 no block consisting of a structural unit derived from an aromatic vinyl compound, in which the value α represented by the following mathematical formula (i) is 0.60 to 0.98 when 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; and (B) one or more polymers selected from the group consisting of acrylonitrile butadiene rubber, hydrogenated acrylonitrile butadiene rubber, acrylic rubber, and ethylene-vinyl acetate copolymer. α=(p+(0.5×r)) / (p+q+(0.5×r)+s) …(i) [ka]

[0008] [2] The polymer composition according to [1], further comprising (C) one or more components selected from the group consisting of natural rubber, butadiene rubber, chloroprene rubber, isoprene rubber, styrene-butadiene rubber, styrene-based block copolymers, polyolefins, and ethylene-α-olefin copolymers. [3] The polymer composition according to [1], comprising, as the component (A), a polymer having a functional group containing at least one element selected from the group consisting of nitrogen, oxygen, sulfur, phosphorus, tin, and silicon. [4] The polymer composition according to [1], wherein the proportion of the component (A) is 10 to 90 mass % when the total amount of the component (A), the component (B), and the component (C) is 100 mass %. [5] The polymer composition according to [1], further comprising (D) a filler. [6] The polymer composition according to [1], further containing sulfur. [7] The polymer composition according to [1], further comprising an organic peroxide. [8] A crosslinked product obtained by curing the polymer composition according to [6] or [7]. [9] A hose using the cross-linked body described in [8].

[10] A sealing member using the crosslinked body described in [8].

[11] A window wiper using the crosslinked body described in [8].

[12] A shoe sole using the crosslinked body described in [8].

[13] A foam material using the crosslinked material described in [8]. [Effects of the Invention]

[0009] According to one aspect of the present invention, a crosslinked rubber having excellent heat resistance and durability can be obtained, and can be used to produce hoses, sealing materials, etc. According to another aspect of the present invention, a crosslinked rubber having excellent impact resilience can be obtained, and can be used to produce shoe soles, foam materials, etc. 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 specific conjugated diene-based polymer and (B) one or more polymers selected from the group consisting of acrylonitrile butadiene rubber, hydrogenated acrylonitrile butadiene rubber, and ethylene-vinyl acetate copolymer. The components contained in the composition and the components that may be optionally blended are described in detail below.

[0012] <Component (A)> The conjugated diene polymer of component (A) (hereinafter also referred to as "(A) 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] In addition, (A) the conjugated diene polymer 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 (A) 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 (A) 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, it is preferable that the (A) conjugated diene polymer 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 (A) 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 (A) conjugated diene polymer can be produced by a method including the following polymerization step and hydrogenation step. The (A) 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 (A) conjugated diene polymer will be described together with the method for producing the (A) 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 (A) 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 (A) 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 the composition, the inorganic filler can be well dispersed.

[0024] The proportion of structural units derived from aromatic vinyl compounds in the (A) conjugated diene polymer is preferably more than 0% by mass and not more than 50% by mass relative to all structural units constituting the (A) 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 (A) 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 (A) 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 (A) 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 (A) may not have a block consisting of structural units derived from an aromatic vinyl compound.

[0026] Here, in this specification, the statement that the (A) conjugated diene polymer "does not have blocks consisting of structural units derived from aromatic vinyl compounds" does not exclude the (A) conjugated diene polymer 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 (A) conjugated diene polymer 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 (A) conjugated diene polymer 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 (A) 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 (A) 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 reaction 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 (A) 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 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 (A) conjugated diene polymer is less than 0.50, the amount of unsaturated bonds in the (A) conjugated diene polymer is large, resulting in a large change in Mooney viscosity due to differences in the desolvation time. This may result in instability in the quality of the (A) conjugated diene polymer or increased heat accumulation and combustibility of the (A) conjugated diene polymer adhering to equipment. Furthermore, there is a concern that the instability in the quality of the (A) conjugated diene polymer may result in a decrease in the strength and viscoelastic properties of the crosslinked product. If the α value of the (A) conjugated diene polymer is greater than 0.98, crosslinking may not proceed sufficiently, resulting in a decrease in the strength and viscoelastic properties of the crosslinked product. From this perspective, the α value of the (A) conjugated diene polymer is more preferably 0.55 or greater, even 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 (A) 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 (A) a 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 (A) conjugated diene polymer, measured using gel permeation chromatography (GPC) in terms of polystyrene, is preferably 1.5 × 10 in order to obtain 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 polymer (i.e., aggregate of different molecular weights) measured by GPC for (A) conjugated diene polymer 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 obtained crosslinked product. The molecular weight distribution of (A) conjugated diene polymer is more preferably 1.2 or more. The molecular weight distribution of (A) conjugated diene polymer is more preferably 3.5 or less, and even more preferably 3.0 or less.

[0054] The proportion of the modified polymer in the (A) conjugated diene polymer is preferably 10% by mass or more relative to the total amount of the (A) conjugated diene polymer. When the proportion of the modified polymer in the (A) 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 (A) 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 (A) 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 reaction rate 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 measurement and quantifying the amount of unreacted terminal modifier.

[0055] <(B) component> The component (B) used in the present composition is one or more polymers selected from the group consisting of acrylonitrile butadiene rubber, hydrogenated acrylonitrile butadiene rubber, acrylic rubber, and ethylene vinyl acetate copolymer (hereinafter also referred to as "component (B)").

[0056] (B1) Acrylonitrile butadiene rubber (NBR), hydrogenated acrylonitrile butadiene rubber (HNBR) The acrylonitrile butadiene rubber (NBR) of the component (B1) used in this composition is a copolymer of acrylonitrile and 1,3-butadiene, and the hydrogenated acrylonitrile butadiene rubber (HNBR) is a polymer in which the double bonds of NBR are hydrogenated. The amount of bound acrylonitrile contained in the polymer of NBR or HNBR is preferably 15 to 50 mass%. The amount of bound acrylonitrile can be measured based on JIS K 6384:2016. The iodine value of HNBR is not particularly limited, but is preferably within the range of 5 to 70.

[0057] (B2) Acrylic rubber The acrylic rubber (B2) used in this composition is obtained by copolymerizing (meth)acrylic acid esters such as ethyl (meth)acrylate, butyl (meth)acrylate, and methoxyethyl (meth)acrylate, and is a polymer containing (meth)acrylic acid ester monomer units preferably at 30 mass% or more in the polymer. Examples of monomers other than (meth)acrylic acid esters include α,β-ethylenically unsaturated carboxylic acid monomers, monomers having an epoxy group, monomers having a halogen atom, and other monomers having a reactive polar functional group, ethylene, and diene monomers.

[0058] (B3) Ethylene vinyl acetate copolymer The ethylene vinyl acetate copolymer of component (B3) used in the present composition is obtained by copolymerizing ethylene and vinyl acetate, and the vinyl acetate content in the polymer is preferably 3 to 50 mass %.

[0059] The content of component (B) used in the present composition is determined appropriately depending on the intended use, but is preferably 10 to 90 mass % and more preferably 15 to 85 mass % based on the total polymer components. Furthermore, the component (B) used in the present composition may be one of the components (B1) to (B3) described above, or a combination of multiple components. Examples of multiple components include the use of multiple types of NBR with different acrylonitrile contents.

[0060] <(C) component> The present composition may contain, as an optional polymer component, one or more polymer components selected from the group consisting of natural rubber, butadiene rubber, chloroprene rubber, isoprene rubber, styrene-butadiene rubber, styrene-based block copolymers, polyolefins, and ethylene-α-olefin copolymers, within the scope that does not impair the effects of the present invention.

[0061] Here, commercially available products can be used for component (C). The styrene-butadiene rubber preferably has a styrene content of 50% by mass or less. The styrene-based block copolymer preferably has a conjugated diene block, and polymers in which the double bonds of the conjugated diene block have been hydrogenated are also preferred.

[0062] The content of component (C) used in the present composition is determined appropriately depending on the intended use, but is preferably 40 mass % or less, more preferably 35 mass % or less, based on the total polymer components. Furthermore, the component (C) used in the present composition may be one of the specific components shown above, or a combination of multiple components. <Other polymer components>

[0063] The present composition may contain a polymer component that does not fall under any of the components (A), (B), and (C). Examples of such a polymer component include polyether, polyester, and polyamide. In the present invention, components (A), (B), and (C) and other polymer components are collectively referred to as the "polymer component."

[0064] <(D) component> The composition may contain a filler (D). Component (D) may be any known filler, such as carbon black, silica, talc, clay, titanium oxide, magnesium carbonate, or a metal compound represented by the following formula (7): mM xSiO y zH2O (7) (In the formula, M is at least one selected from the group consisting of a 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.)

[0065] 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 amount of nitrogen adsorbed to the surface of carbon black measured in accordance with JIS K6217-2:2001 "Part 2: Determination of specific surface area - Nitrogen adsorption method - Single point method." Carbon black may be used alone or in combination of two or more types.

[0066] ·silica The composition may contain silica. By incorporating silica, the processability of the polymer composition can be improved.

[0067] 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.

[0068] Other fillers In the present composition, in addition to carbon black and silica, talc, clay, calcium carbonate, magnesium oxide, and a metal compound represented by the following formula (7) can be used as the inorganic filler. mM xSiOy zH2O (7) (In the formula, M is at least one selected from the group consisting of a 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. Specific examples of metal compounds 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.

[0069] In the present composition, the blend amount of component (D) is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and preferably 150 parts by mass or less, more preferably 130 parts by mass or less, per 100 parts by mass of the polymer component. When the blend amount of the inorganic filler in the present composition is within the above range, a good balance between strength and processability can be achieved.

[0070] Component (E): 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.

[0071] (F) Component: Extension 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.

[0072] <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, foaming agents, foaming aids, 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.

[0073] <<Method for producing polymer composition>> The present composition can be obtained by mixing (A) the conjugated diene polymer with (B) the component (B). The mode of mixing (A) the rubber component with (B) to obtain the present composition is not particularly limited.

[0074] A blended composition (hereinafter also referred to as "polymer composition P") can be obtained as another embodiment of the present composition by blending the rubber component (A) and the component (B), and, if necessary, the various components described above (components (C) to (F), etc.). The blended composition can be obtained by mixing the polymer composition P with various additives that are 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).

[0075] The method for producing the hose, sealing member, window wiper, shoe sole, and foam material of the present invention is not particularly limited, and they can be produced by known production methods.

[0076] 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.

[0077] According to the present disclosure described above, the following means are provided. [Measure 1] (A) A conjugated diene-based 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, and which has a random copolymerization portion of a structural unit derived from a conjugated diene compound and a structural unit derived from an aromatic vinyl compound, but does not have a block consisting of a structural unit derived from an aromatic vinyl compound; and (B) one or more polymers selected from the group consisting of acrylonitrile butadiene rubber, hydrogenated acrylonitrile butadiene rubber, acrylic rubber, and ethylene vinyl acetate copolymer; A polymer composition comprising: α=(p+(0.5×r)) / (p+q+(0.5×r)+s) …(i) [ka] [Measure 2] The polymer composition according to [Means 1] further contains (C) one or more components selected from the group consisting of natural rubber, butadiene rubber, chloroprene rubber, isoprene rubber, styrene-butadiene rubber, styrene-based block copolymers, polyolefins, and ethylene-α-olefin copolymers. [Measure 3] The polymer composition according to [Means 1] or [Means 2], which contains, as the component (A), 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 4] The polymer composition according to any one of [Means 1] to [Means 3], wherein the proportion of the component (A) is 10 to 90 mass % when the total amount of the component (A), the component (B), and the component (C) is 100 mass %. [Means 5] The polymer composition according to any one of [Means 1] to [Means 4], further comprising (D) a filler. [Measure 6] The polymer composition according to [Means 5], wherein the (D) filler is one or more fillers selected from the group consisting of carbon black, silica, talc, clay, calcium carbonate, titanium oxide, magnesium carbonate, and a metal compound represented by the following formula (7): mM xSiOy zH2O (7) [In the formula, M is at least one metal selected from the group consisting of aluminum, magnesium, titanium, calcium, and zirconium, oxides or hydroxides of these metals, hydrates thereof, or carbonates of these metals, and m, x, y, and z are integers of 1 to 5, 0 to 10, 2 to 5, and 0 to 10, respectively.] [Means 7] The polymer composition according to any one of [Means 1] to [Means 6], further containing sulfur. [Means 8] The polymer composition according to any one of [Means 1] to [Means 6], further comprising an organic peroxide. [Means 9] A crosslinked product obtained by curing the polymer composition according to [Means 7] or [Means 8]. [Means 10] A hose using the crosslinked body described in [Means 9]. [Means 11] A sealing member using the crosslinked body according to [Means 9]. [Means 12] A window wiper using the crosslinked product according to [Means 9]. [Means 13] A shoe sole using the crosslinked body described in [Means 9]. [Means 14] A foam material using the crosslinked product described in [Means 9]. [Example]

[0078] 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.

[0079] [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 1Calculated from H-NMR spectrum.

[0080] <Production of hydrogenated conjugated diene polymer> [Production Example 1: Production of Hydrogenated Conjugated Diene Polymer A and Its Properties] A 50-liter autoclave reactor with a nitrogen-purged interior was charged with 25,800 g of cyclohexane, 65 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 31 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, 35 mmol of diethylaluminum chloride, 10 mmol of bis(η5-cyclopentadienyl)titanium(furfuryloxy)chloride, and 21 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, and 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 A-1. The hydrogenated conjugated diene polymer P1 had a bound styrene content of 10 mass % and a hydrogenation rate of 55% (α=0.55).

[0081] [Manufacturing Examples 2 to 6] The same operations as in Production Example 1 were carried out except for changing the amount of hydrogen supplied, to obtain hydrogenated conjugated diene polymer A-2 with a hydrogenation rate of 70% and hydrogenated conjugated diene polymer A-3 with a hydrogenation rate of 95%. Similarly, by changing the amounts of styrene and butadiene charged and the integrated hydrogen value of the hydrogenation reaction, hydrogenated conjugated diene polymer A-4 with a bound styrene content of 40% by mass and a hydrogenation rate of 60%, hydrogenated conjugated diene polymer A-5 with a bound styrene content of 40% by mass and a hydrogenation rate of 90%, and hydrogenated conjugated diene polymer A-6 with a bound styrene content of 25% by mass and a hydrogenation rate of 90% were obtained.

[0082] <Production of polymer composition and crosslinked product> [Example 1] -Production of polymer compositions In the first stage of mixing, hydrogenated conjugated diene polymer A-1, NBR, carbon black, plasticizer, softener, zinc oxide, and stearic acid were kneaded according to the formulation in Table 1 at a filling rate of 72% and a rotation speed of 60 rpm using a plastomill (capacity: 250 cc) equipped with a temperature control device. Next, in the second stage of mixing, the compound obtained above was cooled to room temperature, and then sulfur and a vulcanization accelerator were added and kneaded. This was molded and vulcanized in a vulcanization press at 160°C for a predetermined time to obtain a crosslinked product. The following property evaluations were performed using the obtained crosslinked product. Furthermore, in Examples 2 to 17 and Comparative Examples 1 to 3, the same procedures were performed, except that the types and proportions of the components used were as shown in Table 1, and property evaluations were performed. The results are shown in Table 1.

[0083] <Heat resistance> In accordance with JIS K 6257:2017, the crosslinked product was left in a Geer oven at 100°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

[0084] <Oil resistance> In accordance with JIS K 6258:2016, a test for swelling resistance in oil was conducted by immersing the crosslinked sheet in test lubricating oil (No. 3 oil IRM903) adjusted to 100°C for 72 hours. In the oil resistance test, the volume of the crosslinked sheet before and after immersion in the lubricating oil was measured, and the volume change rate ΔV (unit: %) after immersion in the lubricating oil was calculated according to the formula: ΔV = ([volume after immersion in lubricating oil - volume before immersion in lubricating oil] / volume before immersion in lubricating oil) × 100, and evaluated according to the following criteria. A: ΔV is less than 10% B: ΔV is 10% or more and less than 30% C: ΔV is 30% or more

[0085] <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 20% and subjected to ozone degradation for 72 hours under conditions of an ozone concentration of 50 pphm and 40°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.

[0086] [Table 1]

[0087] The materials used in the examples and comparative examples in Table 1 are as follows. NBR: Manufactured by ENEOS Materials, product name "NBR N230S" Hydrogenated NBR: Zeon Corporation, product name "Zetto Pole 2020" ACM: Manufactured by Nippon Zeon Co., Ltd., product name "Nipol AR51" CR: Denka Co., Ltd., product name "PN-40NS" EPDM: ENEOS Materials, product name "EP65" Carbon black: Cabot Corporation, product name "Showblack N550" Plasticizer: ADEKA Adekaiser RS-107 Softener: Naphthenic oil 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. Sulfur: Tsurumi Chemical Industry Co., Ltd., product name "Kinka Brand Precipitated Sulfur"

[0088] [Example 18] -Production of polymer compositions Using a pressure kneader (capacity: 2500 cc) equipped with a temperature control device, hydrogenated conjugated diene polymer A-1, EVA, silica, calcium carbonate, titanium oxide, zinc oxide, and stearic acid were kneaded according to the formulation in Table 2 at a filling rate of 60% and a rotation speed of 40 rpm in the first stage of kneading. Next, in the second stage of kneading, the resulting mixture was cooled to room temperature, and then peroxide, a blowing agent, and a foaming aid were added and kneaded. The mixture was molded, and crosslinked and foamed in a press at 170°C for a predetermined time to obtain a crosslinked foam. The resulting crosslinked foam was evaluated for the following properties. Furthermore, in Examples 19 to 26 and Comparative Examples 4 to 8, the same procedures were followed, except that the types and proportions of the components used were as shown in Table 2, and the properties were evaluated. The results are shown in Table 2.

[0089] <Rebound resilience> According to JIS K 6255:2013, a cylindrical test piece with a diameter of 29 mm was punched out from a 10 mm thick foam sheet. The rebound resilience of this test piece was measured using a Lübke type rebound resilience tester and expressed as a percentage. The higher the value, the better.

[0090] <Compression set> According to JIS K 6262:2013, a cylindrical test piece with a diameter of 29 mm was punched out from a 10 mm thick sheet. This test piece was compressed to 50% using a special tool and left at 70°C for 24 hours, after which the compression set (unit: %) was measured. The smaller the value, the better.

[0091] <Contractility> After molding the crosslinked foam, a 100 mm wide mark was made on the surface of the crosslinked foam to prepare a sample. The sample was left at 25°C for 24 hours, and the width of the mark was measured. The shrinkage rate of the rubber was calculated using the following formula and evaluated according to the following criteria. Shrinkage rate (%) = [(100 - length of sample after standing) / 100] x 100 A: Shrinkage rate is 5% or less B: Shrinkage rate is over 5% and 10% or less C: Shrinkage rate is over 10%

[0092] [Table 2]

[0093] The materials used in the examples and comparative examples in Table 2 are as follows. EVA: Tosoh Corporation, consumer name "Ultrasen EVA630" SEBS: Manufactured by ENEOS Materials, product name "DYNARON 8903P" EPDM: ENEOS Materials, product name "EP57" EOM: Mitsui Chemicals, product name "Tafmer DF630" PE: Made by Japan Polyethylene Corporation, product name "Novatec UJ370" IR: ENEOS Materials, product name "IR2200" SBR: ENEOS Materials, product name "ESBR 1502" Silica: Tosoh Silica Corporation, product name "Nipsil VN3" Calcium carbonate: Shiraishi Calcium Co., Ltd., product name "Silver W" Titanium oxide (anatase type): Sakai Chemical Industry Co., Ltd., product name "A-190" Peroxide: NOF Corporation, product name "Perkmyl D-40" (Dicumyl peroxide 40% product) Foaming agent: Eiwa Chemical Industry Co., Ltd., product name "Vinihole AC#3" Foaming aid: Eiwa Chemical Industry Co., Ltd., product name "Cell Paste 101"

[0094] From the above results, it is clear that the crosslinked product of the present invention is excellent in heat resistance, oil resistance, ozone resistance, impact resilience, compression set and shrinkage.

Claims

1. (A) A conjugated diene-based polymer in which the value α represented by the following mathematical 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, and the polymer has a random copolymerization portion of a structural unit derived from a conjugated diene compound and a structural unit derived from an aromatic vinyl compound, but does not have a block composed of a structural unit derived from an aromatic vinyl compound; and (B) one or more polymers selected from the group consisting of acrylonitrile butadiene rubber, hydrogenated acrylonitrile butadiene rubber, acrylic rubber, and ethylene vinyl acetate copolymer; A polymer composition comprising: α=(p+(0.5×r)) / (p+q+(0.5×r)+s)…(i) 【Chemistry 1】

2. The polymer composition according to claim 1, further comprising (C) one or more components selected from the group consisting of natural rubber, butadiene rubber, chloroprene rubber, isoprene rubber, styrene-butadiene rubber, styrene-based block copolymers, polyolefins, and ethylene-α-olefin copolymers.

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

4. 2. The polymer composition according to claim 1, wherein a proportion of the component (A) is 10 to 90 mass% when the total amount of the component (A), the component (B), and the component (C) is 100 mass%.

5. The polymer composition according to claim 1 , further comprising (D) a filler.

6. 6. The polymer composition according to claim 5, wherein the filler (D) is one or more fillers selected from the group consisting of carbon black, silica, talc, clay, calcium carbonate, magnesium carbonate, and a metal compound represented by the following formula (7): mM・xSiO y ・zH ２ O (7) [In the formula, M is at least one metal selected from the group consisting of aluminum, magnesium, titanium, calcium, and zirconium, oxides or hydroxides of these metals, hydrates thereof, or carbonates of these metals, and m, x, y, and z are integers of 1 to 5, 0 to 10, 2 to 5, and 0 to 10, respectively.]

7. The polymer composition according to claim 1 , further comprising sulfur.

8. The polymer composition according to claim 1, further comprising an organic peroxide.

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

10. A hose using the crosslinked body according to claim 9.

11. A sealing member using the crosslinked product according to claim 9.

12. A window wiper using the crosslinked product according to claim 9.

13. A shoe sole using the crosslinked product according to claim 9.

14. A foam material using the crosslinked product according to claim 9.

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