Polymer compositions, crosslinked materials, and tires

Abstract

Provided is a polymer composition containing a conjugated diene polymer (A) and a liquid polymer (B), wherein: the conjugated diene polymer (A) contains a polymer (A1) satisfying the condition of expression (i) when the structural ratio (molar ratio) in the polymer of the structural unit represented by formula (1), the structural unit represented by formula (2), the structural unit represented by formula (3), and the structural unit represented by formula (4) are p, q, r, and s, respectively; the glass transition temperature of the polymer (A1) is -40°C or less; and the liquid polymer (B) is a polybutadiene, polyisoprene, polyisobutylene, polybutene, or the like. Expression (i): 0.75 ≤ (p + (0.5 × r)) / (p + q + (0.5 × r) + s) ≤ 0.97.

Description

Cross-reference of related applications

[0001] This application is based on Japanese Patent Application No. 2020-197516, filed on November 27, 2020, and its contents are incorporated herein by reference. [Technical Field]

[0002] This disclosure relates to polymer compositions, crosslinked materials, and tires. [Background technology]

[0003] Conjugated diene polymers, such as styrene-butadiene copolymers, are widely used in various industrial products such as pneumatic tires, vibration-damping rubber, and hoses due to their excellent properties including heat resistance, abrasion resistance, mechanical strength, and moldability. Furthermore, it has been proposed to obtain high-strength and low-abrasion vulcanized rubber by using hydrogenated conjugated diene polymers, in which some of the unsaturated bonds in conjugated diene polymers are hydrogenated (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2015 / 064646 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In the production of winter tires and all-season tires, a polymer having a relatively low glass transition temperature (Tg) is generally used to impart flexibility at low temperatures to the vulcanized rubber. Here, in the vulcanized rubber obtained using a polymer with a low Tg, the abrasion resistance and the ice grip performance are in an antagonistic relationship. When attempting to impart ice grip performance to the vulcanized rubber obtained using a polymer with a low Tg, the abrasion resistance tends to decrease. In order to develop a rubber material for winter tires or all-season tires that has both abrasion resistance and ice grip performance in a well-balanced manner, the inventors considered using a hydrogenated conjugated diene polymer that exhibits high strength and high abrasion resistance.

[0006] However, there is concern that vulcanized rubber containing a hydrogenated conjugated diene polymer does not have sufficient ice grip performance and cannot fully satisfy the performance required when applied to winter tires or all-season tires. Also, in winter tires and all-season tires, not only good ice grip performance but also good rolling resistance is required. Furthermore, when a hydrogenated conjugated diene polymer is blended into a polymer composition, there is concern that the processability during kneading of the polymer composition will deteriorate.

[0007] The present disclosure has been made in view of the above problems, and a main object thereof is to provide a polymer composition that can produce a vulcanized rubber having high strength and high abrasion resistance, good ice grip performance and rolling resistance, and good processability.

Means for Solving the Problems

[0008] The inventors have conducted studies to solve the above problems. As a result, they have found that the above problems can be solved by combining a specific conjugated diene polymer and a specific additive. According to the present disclosure, the following means are provided.

[0009] [1] A polymer composition containing (A) a conjugated diene polymer and (B) a liquid polymer, wherein the (A) conjugated diene polymer is a polymer that satisfies the condition of the following mathematical formula (i) when the composition ratios (molar ratios) of the structural units represented by the following formula (1), the structural units represented by the following formula (2), the structural units represented by the following formula (3), and the structural units represented by the following formula (4) in the polymer are p, q, r, and s, respectively. The glass transition temperature of the (A1) polymer is -40 °C or lower, and the (B) liquid polymer is at least one selected from the group consisting of polybutadiene and its hydrogenated product, polyisoprene and its hydrogenated product, styrene-butadiene copolymer with a styrene content of 20% by mass or less and its hydrogenated product, styrene-isoprene copolymer and its hydrogenated product, butadiene-isoprene copolymer and its hydrogenated product, isoprene-butadiene-styrene copolymer and its hydrogenated product, polyisobutylene, polybutene, ethylene-α-olefin copolymer, ethylene-propylene-diene copolymer, and polypiperylene. Mathematical formula (i): 0.75 ≦ (p + (0.5 × r)) / (p + q + (0.5 × r) + s) ≦ 0.97

Chemical formula

Advantages of the Invention

[0010] According to the present disclosure, a vulcanized rubber having high strength, high wear resistance, good ice grip performance and rolling resistance can be obtained, and a polymer composition having good processability can be obtained.

Embodiments for Carrying out the Invention

[0011] ≪Polymer Composition≫ The polymer composition of this disclosure (hereinafter also simply referred to as "this composition") contains (A) a conjugated diene polymer and (B) a liquid polymer. The components contained in this composition, and components that may be added as needed, are described below. In this specification, numerical ranges indicated using "~" include the values ​​indicated before and after "~" as the lower and upper limits, respectively.

[0012] <(A) Conjugated diene polymers> This composition contains a conjugated diene polymer in which, when the constituent ratios (molar ratios) of the structural units represented by the following formula (1), the following formula (2), the following formula (3), and the following formula (4) are p, q, r, and s respectively, the polymer satisfies the condition of the following formula (i) (hereinafter also referred to as "(A1) polymer"). Formula (i): 0.75≦(p+(0.5×r)) / (p+q+(0.5×r)+s)≦0.97 [ka]

[0013] (A1) As the polymer, a hydrogenated polymer having structural units derived from a conjugated diene compound can be used. The (A1) polymer as a hydrogenated product can be produced by first polymerizing a monomer containing a conjugated diene compound to obtain an unhydrogenated conjugated diene polymer, and then performing a hydrogenation reaction on the obtained polymer.

[0014] (A1) 1,3-butadiene is preferably used as the conjugated diene compound constituting the polymer. In addition, in polymerization to obtain polymer (A1), conjugated diene compounds other than 1,3-butadiene may be used. Specific examples of conjugated diene compounds other than 1,3-butadiene include isoprene, 2,3-dimethyl-1,3-butadiene, and 1,3-pentadiene. Among these, isoprene is preferred as the conjugated diene compound other than 1,3-butadiene. Note that a single conjugated diene compound may be used alone, or two or more compounds may be used in combination.

[0015] (A1) The polymer is preferably a copolymer of a conjugated diene compound and an aromatic vinyl compound, from the viewpoint of increasing the strength of the crosslinked material obtained using this composition. Examples of aromatic vinyl compounds used for polymerization include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, N,N-dimethylaminoethylstyrene, and diphenylethylene. Among these, the aromatic vinyl compound is particularly preferably at least one of styrene and α-methylstyrene. The aromatic vinyl compound can be used individually or in combination of two or more.

[0016] (A1) When the polymer is a copolymer of a conjugated diene compound and an aromatic vinyl compound, it is preferable, in particular, that it is a copolymer of 1,3-butadiene and styrene, as it has high living properties in anionic polymerization. (A1) The polymer is preferably a random copolymer in which the distribution of the conjugated diene compound and the aromatic vinyl compound is irregular, as it can improve the dispersibility of the filler incorporated into the polymer composition. The random copolymer of the conjugated diene compound and the aromatic vinyl compound may further have block portions made of the conjugated diene compound or the aromatic vinyl compound, as long as the effects of this disclosure are obtained.

[0017] In copolymers of conjugated diene compounds and aromatic vinyl compounds, the content of structural units derived from the aromatic vinyl compound is preferably 3 to 45% by mass relative to the total amount of monomer units constituting the copolymer, from the viewpoint of improving the strength, abrasion resistance, and low hysteresis loss characteristics of the crosslinked material obtained using this composition, as well as improving ice grip performance. More preferably, the content of structural units derived from the aromatic vinyl compound is 4% by mass or more, and even more preferably 5% by mass or more, relative to the total amount of monomer units constituting the copolymer.

[0018] Furthermore, the content of structural units derived from aromatic vinyl compounds is more preferably 40% by mass or less, even more preferably 35% by mass or less, even more preferably 30% by mass or less, and particularly preferably 25% by mass or less, relative to the total amount of monomer units constituting the copolymer, in order to sufficiently improve ice grip performance. By keeping the content of aromatic vinyl compound units within the above range, it is possible to achieve both productivity and strength. The (A1) polymer preferably contains 50 to 97% by mass of 1,3-butadiene units, 3 to 45% by mass of aromatic vinyl compound units, and 0 to 30% by mass of conjugated diene compound units other than 1,3-butadiene, based on 100% by mass of the total amount of monomer units constituting the (A1) polymer. This blending ratio is preferable because it is possible to maintain high strength of the crosslinked body while improving ice grip performance in a well-balanced manner.

[0019] Furthermore, the conjugated diene compounds and aromatic vinyl compounds exemplified above all have similar effects in that they can be used to obtain conjugated diene polymers having active ends. Therefore, even those not described in the examples below can be used in this disclosure.

[0020] In polymerization, other monomers besides conjugated diene compounds and aromatic vinyl compounds may be used. Examples of other monomers include acrylonitrile, methyl (meth)acrylate, and ethyl (meth)acrylate. The content of structural units derived from other monomers is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less, based on the total amount of monomers constituting the (A1) polymer.

[0021] (A1) Any polymerization method can be used to obtain the polymer, including solution polymerization, gas-phase polymerization, or bulk polymerization, but solution polymerization is particularly preferred. In addition, either batch or continuous polymerization can be used. When using solution polymerization, one example of a specific polymerization method is to polymerize monomers containing a conjugated diene compound in an organic solvent in the presence of a polymerization initiator and, if necessary, a randomizer.

[0022] As polymerization initiators, at least one of alkali metal compounds and alkaline earth metal compounds can be used. Among the alkali metal compounds and alkaline earth metal compounds, those commonly used as initiators for anionic polymerization can be used. Specific examples of polymerization initiators include methyllithium, ethyllithium, n-propyllithium, n-butyllithium, sec-butyllithium, t-butyllithium, 1,4-dilithiobutane, phenyllithium, stilbenilithium, naphthyllithium, naphthylsodium, naphthylpotassium, di-n-butylmagnesium, di-n-hexylmagnesium, ethoxypotassium, calcium stearate, and the like. Among these, lithium compounds are preferably used as polymerization initiators.

[0023] The polymerization reaction may be carried out in the presence of a compound obtained by mixing at least one of the alkali metal compounds and alkaline earth metal compounds mentioned above with a compound having a functional group that interacts with silica (hereinafter also referred to as the "initial modifier"). By carrying out polymerization in the presence of the initial modifier, a functional group that interacts with silica can be introduced to the polymerization initiation end of the (A1) polymer. Furthermore, introducing a functional group that interacts with silica to the initiation end of the (A1) polymer is preferable because it can improve the low hysteresis loss performance (low fuel consumption performance) of the vulcanized rubber.

[0024] In this specification, "interaction" means the formation of a covalent bond between molecules or the formation of an intermolecular force weaker than a covalent bond (e.g., electromagnetic forces acting between molecules such as ion-dipole interactions, dipole-dipole interactions, hydrogen bonds, van der Waals forces, etc.). A "functional group that interacts with silica" means a group having at least one atom that interacts with silica (e.g., nitrogen, sulfur, phosphorus, oxygen, silicon, etc.). The silicon atom of a "functional group that interacts with silica" is the silicon atom in the hydrocarbyloxysilyl group.

[0025] As an initiating modifier, a reaction product of a lithium compound such as alkyllithium and a nitrogen-containing compound such as a secondary amine compound can be used. Examples of nitrogen-containing compounds include dimethylamine, diethylamine, dipropylamine, dibutylamine, dodecamethyleneimine, N,N'-dimethyl-N'-trimethylsilyl-1,6-diaminohexane, piperidine, pyrrolidine, hexamethyleneimine, heptamethyleneimine, dicyclohexylamine, N-methylbenzylamine, di-(2-ethylhexyl)amine, diallylamine, morpholine, N-(trimethylsilyl)piperazine, N-(tert-butyldimethylsilyl)piperazine, and 1,3-ditrimethylsilyl-1,3,5-triazinan.

[0026] Furthermore, when polymerization is carried out in the presence of an initiator modifier, the initiator modifier may be prepared by pre-mixing an alkali metal compound or alkaline earth metal compound with a nitrogen-containing compound, and the prepared mixture may be added to the polymerization system before polymerization is carried out. Alternatively, the initiator modifier may be prepared by adding an alkali metal compound or alkaline earth metal compound and a nitrogen-containing compound to the polymerization system and mixing the two in the polymerization system before polymerization is carried out.

[0027] A randomizer can be used to adjust the content of 1,2-vinyl bonds (vinyl content) in the polymer obtained by the above polymerization. Examples of randomizers include dimethoxybenzene, tetrahydrofuran, dimethoxyethane, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, 2,2-di(tetrahydrofuryl)propane, 2-(2-ethoxyethoxy)-2-methylpropane, triethylamine, pyridine, N-methylmorpholine, and tetramethylethylenediamine. A randomizer can be used alone or in combination of two or more.

[0028] Any organic solvent that is inert to the reaction can be used as the organic solvent for polymerization. For example, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, etc., can be used. Among these, hydrocarbons having 3 to 8 carbon atoms are preferred. Specific examples include 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 individually or in combination of two or more.

[0029] When solution polymerization is used, the monomer concentration in the reaction solvent is preferably 5 to 50% by mass, and more preferably 10 to 30% by mass, from the viewpoint of maintaining a balance between productivity and ease of polymerization control. The polymerization reaction temperature is preferably -20 to 150°C, more preferably 0 to 120°C, and particularly preferably 20 to 100°C. Furthermore, the polymerization reaction is preferably carried out under pressure sufficient to keep the monomer substantially in the liquid phase. Such pressure can be obtained by methods such as pressurizing the reactor with a gas that is inert to the polymerization reaction.

[0030] The 1,2-vinyl content (vinyl content) of the conjugated diene polymer obtained by the above polymerization is preferably 5 to 70 mol%. When the vinyl content is 5 mol% or more, the grip properties tend to be good, and when it is 70 mol% or less, it tends to show good abrasion resistance. From this viewpoint, the vinyl content is more preferably 10 mol% or more, and even more preferably 15 mol% or more. Furthermore, the vinyl content is more preferably 60 mol% or less, and even more preferably 50 mol% or less. 1 These values ​​were measured using an H-NMR spectrometer.

[0031] The above polymerization can yield a conjugated diene polymer having an active end. To terminate the polymerization, the polymer having an active end may be reacted with an alcohol or hydrogen, or it may be reacted with a compound having a functional group that interacts with silica (hereinafter also referred to as a "end modifier") or a coupling agent. By reacting the conjugated diene polymer having an active end with a end modifier, a modified conjugated diene polymer can be obtained as the (A1) polymer, in which the polymerization termination end is modified by a functional group that interacts with silica. Furthermore, using a polymer in which a functional group that interacts with silica is introduced at the polymerization end as the (A1) polymer is preferable in that it can improve the low hysteresis loss performance. In particular, it is preferable that the (A1) polymer has at least one functional group selected from the group consisting of an amino group, a nitrogen-containing heterocyclic group, a phosphino group, a hydroxyl group, a thiol group, and a hydrocarbyloxysilyl group. In this specification, "active end" means a part of the molecular chain other than the structure derived from the monomer having a carbon-carbon double bond (more specifically, a metallic end).

[0032] The end modifier is not particularly limited as long as it has a functional group that interacts with silica and can react with the active end of the conjugated diene polymer. Among end modifiers, compounds having one atom selected from the group consisting of nitrogen, sulfur, phosphorus, oxygen, and silicon atoms, and to which no active hydrogen is bonded, are preferably used. The end modifier is especially preferably a compound having one or more functional groups selected from the group consisting of an amino group, a group having a carbon-nitrogen double bond, a nitrogen-containing heterocyclic group, a phosphino group, a cyclic ether group, a cyclic thioether group, a protected hydroxyl group, a protected thiol group, and a hydrocarbyloxysilyl group, and that can react with the polymerization active end. The amino group is preferably a protected primary amino group, a protected secondary amino group, or a tertiary amino group.

[0033] As the terminal modifier, at least one selected from the group consisting of compounds represented by the following formula (5) and compounds represented by the following formula (6) can preferably be used. [Chemical formula] (In formula (5), A 1 has at least one atom selected from the group consisting of nitrogen, phosphorus, oxygen, sulfur, and silicon, has no active hydrogen, and is a monovalent functional group bonded to R 5 by a nitrogen atom, a phosphorus atom, an oxygen atom, a sulfur atom, a silicon atom, or a carbon atom contained in a carbonyl group, or is a (thio) epoxy group. R 3 and R 4 are each independently a hydrocarbyl group. R 5 is a hydrocarbylene group. r is an integer from 0 to 2. However, when r is 2, a plurality of R 3 in the formula are the same as or different from each other. When r is 0 or 1, a plurality of R 4 in the formula are the same as or different from each other.) [Chemical formula] (In formula (6), A 2 has at least one atom selected from the group consisting of nitrogen, phosphorus, oxygen, sulfur, and silicon, has no active hydrogen, and is a monovalent functional group bonded to R 9 by a nitrogen atom, a phosphorus atom, an oxygen atom, a sulfur atom, or a silicon atom, or is a hydrocarbyl group having 1 to 20 carbon atoms. R 6 and R 7 are each independently a hydrocarbyl group. R 8 is a hydrocarbylene group. R 9 is a single bond or a hydrocarbylene group. m is 0 or 1. However, when m is 0, a plurality of R 7 in the formula are the same as or different from each other.)

[0034] In the above formulas (5) and (6), R 3 , R 4 , R 6 , R 7 , and when A is a hydrocarbyl group 2Regarding this, 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 5 and R 9 The hydrocarbylene group represented by 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. 8 The hydrocarbylene group is preferably a linear or branched alkanediyl group having 1 to 20 carbon atoms. From the viewpoint of increasing reactivity with conjugated diene polymers, r is preferably 0 or 1.

[0035] A 1 When the above monovalent functional group is A 1 At least one atom selected from the group consisting of nitrogen, phosphorus, oxygen, sulfur, and silicon may be protected by a protecting group (for example, a trisubstituted hydrocarbylsilyl group). Also, A 2 When the above monovalent functional group is A 2 At least one atom selected from the group consisting of nitrogen, phosphorus, oxygen, sulfur, and silicon may be protected by a protecting group (e.g., a trisubstituted hydrocarbylsilyl group). In this specification, active hydrogen refers to a hydrogen atom bonded to an atom other than a carbon atom, preferably one with a bond energy lower than the carbon-hydrogen bond of polymethylene. A protecting group is A 1 , A 2 This is a functional group that converts the polymerization active end into an inert functional group. The term (thio)epoxy group encompasses both epoxy groups and thioepoxy groups.

[0036] A 1 This may be a group that can become an onium ion by an onium salt generating agent. The terminal modifying agent may be such a group (A 1 By having ), (A1) excellent shape retention can be imparted to the polymer. 1Specific examples include, for instance, nitrogen-containing groups formed by substituting two hydrogen atoms of a primary amino group with two protecting groups, nitrogen-containing groups formed by substituting one hydrogen atom of a secondary amino group with one protecting group, phosphorus-containing groups formed by substituting two hydrogen atoms of a tertiary amino group, imino group, pyridyl group, or primary phosphino group with two protecting groups, phosphorus-containing groups formed by substituting one hydrogen atom of a secondary phosphino group with one protecting group, tertiary phosphino group, epoxy group, thioepoxy group, or hydroxyl group with hydrogen atoms substituted by protecting groups, sulfur-containing groups formed by substituting a hydrogen atom of a thiol group with one protecting group, and hydrocarbyloxycarbonyl groups. Among these, groups having a nitrogen atom are preferred due to their good affinity with silica, and nitrogen-containing groups formed by substituting two hydrogen atoms of a tertiary amino group or primary amino group with two protecting groups are more preferred.

[0037] Specific examples of terminal denaturants include compounds represented by formula (5) above, such as N,N-bis(trimethylsilyl)aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane, N,N',N'-tris(trimethylsilyl)-N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N,N-dimethyl-3-(triethoxysilyl)propylamine, 3-(4-trimethylsilyl-1-piperazino)propylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropyltriethoxysilane.

[0038] Specific examples of compounds represented by formula (6) above include, for example, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1,2-azacyloridine, 2,2-diethoxy-1-(3-trimethoxysilylpropyl)-1,2-azacyloridine, 2,2-dimethoxy-1-phenyl-1,2-azacyloridine, 1-trimethylsilyl-2,2-dimethoxy-1-aza-2-silacyclopentane, 2-(2,2-dimethoxy-1,2-azacyloridine-1-yl)-N,N-diethylethane-1-amine, 2-(2,2-dimethoxy-1,2-azacyloridine-1-yl)-N,N-dimethylethane-1-amine, and 3-(2,2-dimethoxy-1,2-azacyloridine-1-yl)-N,N-diethylpropane-1-amine. As terminal denaturants, one type may be used alone, or two or more types may be used in combination.

[0039] The above-described end-modification reaction can be carried out, for example, as a solution reaction. This solution reaction may be carried out using a solution containing unreacted monomers after the polymerization reaction is complete, or the conjugated diene polymer contained in the solution may be isolated and dissolved in a suitable solvent such as cyclohexane before the reaction. Furthermore, the end-modification reaction may be carried out using either a batch or continuous method. In this case, there are no particular restrictions on the method of adding the end-modifier, and examples include adding it all at once, adding it in installments, or adding it continuously.

[0040] The amount of end-modifier used can be appropriately set according to the type of compound used in the reaction, but is preferably 0.1 molar equivalents or more, more preferably 0.3 molar equivalents or more, relative to the metal atoms in the polymerization initiator that are involved in the polymerization reaction. By using 0.1 molar equivalents or more of end-modifier, the modification reaction can proceed sufficiently, and the dispersibility of the inorganic filler can be suitably improved. The reaction temperature during end-modification is usually the same as the polymerization reaction temperature, preferably -20 to 150°C, more preferably 0 to 120°C, and particularly preferably 20 to 100°C. If the modification reaction temperature is low, the viscosity of the polymer solution tends to increase. Also, if the modification reaction temperature is high, the polymerization active ends tend to be deactivated. The reaction time during end-modification is preferably 1 minute to 5 hours, more preferably 2 minutes to 1 hour.

[0041] Furthermore, for the purpose of adjusting the Mooney viscosity of the (A1) polymer, a coupling agent such as silicon tetrachloride or a polyfunctional epoxy compound (e.g., tetraglycidyl-1,3-bisaminomethylcyclohexane) may be reacted with a conjugated diene polymer having active ends before or after the modification reaction using the end-modifying agent, or simultaneously with the modification reaction using the end-modifying agent. The amount of coupling agent used can be appropriately set according to the desired Mooney viscosity of the (A1) polymer and the compounds used in the reaction, but it is preferable to use an amount of 0.01 to 0.8 molar equivalents relative to the metal atoms involved in the polymerization reaction that the polymerization initiator possesses. As the coupling agent, one type can be used alone or two or more types can be used in combination.

[0042] Next, the modified or unmodified conjugated diene polymer obtained above can be hydrogenated to obtain the (A1) polymer. The method and conditions of the hydrogenation reaction are not critical as long as a conjugated diene polymer with the desired hydrogenation rate is obtained, and any method and conditions may be used. Examples of hydrogenation methods include using a catalyst mainly composed of a titanium organometallic compound as a hydrogenation catalyst, using a catalyst consisting of an organometallic compound of iron, nickel, or cobalt and an organometallic compound such as alkylaluminum, using an organometallic complex of an organometallic compound such as ruthenium or rhodium, and using a catalyst in which metals such as palladium, platinum, ruthenium, cobalt, or nickel are supported on a carrier such as carbon, silica, or alumina. Among the various methods, a method using a titanium organometallic compound alone, or a homogeneous catalyst consisting of a titanium organometallic compound and an organometallic compound of lithium, magnesium, or aluminum (Japanese Patent Publication No. 63-4841, Japanese Patent Publication No. 1-37970), and hydrogenating under mild conditions of low pressure and low temperature is industrially preferred. Furthermore, it exhibits high hydrogenation selectivity for the double bond of butadiene, making it suitable for the purposes of this disclosure.

[0043] Hydrogenation of conjugated diene polymers is carried out in a solvent that is catalyst-inert and in which the conjugated diene polymer is soluble. Preferred solvents include aliphatic hydrocarbons such as n-pentane, n-hexane, and n-octane; alicyclic hydrocarbons such as cyclohexane and cycloheptane; aromatic hydrocarbons such as benzene and toluene; and ethers such as diethyl ether and tetrahydrofuran, either alone or in mixtures thereof.

[0044] Hydrogenation reactions are generally carried out by maintaining a conjugated diene polymer at a predetermined temperature under 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 means an atmosphere that does not react with the substances involved in the hydrogenation reaction, such as helium, neon, or argon. Air and oxygen are undesirable because they oxidize the catalyst and lead to catalyst deactivation. Nitrogen is also undesirable because it acts as a catalyst poison during the hydrogenation reaction and reduces hydrogenation activity. In particular, an atmosphere of hydrogen gas alone inside the hydrogenation reactor is most preferable.

[0045] The hydrogenation reaction process to obtain hydrogenated conjugated diene polymers can be used as a batch process, a continuous process, or a combination thereof. When a titanocenediaryl compound is used as the hydrogenation catalyst, it may be added directly to the reaction solution or as a solution in an inert organic solvent. When the catalyst is used as a solution, any inert organic solvent that does not react with the hydrogenation reaction participants can be used. Preferably, the same solvent is used for the hydrogenation reaction. The amount of catalyst added is 0.02 to 20 mmol per 100 g of the conjugated diene polymer before hydrogenation.

[0046] The (A1) polymer is a conjugated diene polymer that satisfies the above formula (i). That is, the (A1) polymer has a value (hereinafter also referred to as "value θ") defined by the following formula (ii) between 0.75 and 0.97. By setting θ to 0.75 or higher, a crosslinked body can be obtained with sufficiently high strength and wear resistance, and with sufficiently suppressed hardness changes due to thermal aging. For these reasons, θ is preferably 0.78 or higher, more preferably 0.80 or higher, and even more preferably 0.85 or higher. Furthermore, from the viewpoint of ensuring sufficient crosslinking reaction, θ is preferably 0.97 or lower, and preferably 0.95 or lower. Formula (ii): θ=(p+(0.5×r)) / (p+q+(0.5×r)+s)

[0047] The value θ defined by the above formula (ii) corresponds to the hydrogenation rate of the (A1) polymer. For example, when θ is 0.75, the hydrogenation rate of the (A1) polymer is 75%. When θ is 0.97, the hydrogenation rate of the (A1) polymer is 97%. The hydrogenation rate in the polymer can be adjusted, for example, by adjusting the time of the hydrogenation reaction to control the cumulative amount of hydrogen supplied. In this specification, the hydrogenation rate is: 1 These values ​​were measured using an H-NMR spectrometer.

[0048] A preferred method for obtaining the (A1) polymer is to perform solution polymerization of a monomer containing 1,3-butadiene in the presence of an alkali metal compound, carry out a terminal modification reaction using the resulting polymer solution as is, and then subject it to a hydrogenation reaction. This method is also industrially useful. In this case, the (A1) polymer can be obtained by removing the solvent from the solution obtained above and isolating the polymer. Polymer isolation can be carried out, for example, by known solvent removal methods such as steam stripping and drying operations such as heat treatment.

[0049] (A1) The weight-average molecular weight (Mw) of the polymer is preferably 1.0 × 10 5 ~2.0×10 6 Therefore, Mw is 1.0 × 10⁻⁶. 5 With the above conditions, the wear resistance and fuel efficiency of the resulting crosslinked material can be sufficiently high. Furthermore, the weight-average molecular weight is 2.0 × 10⁻⁶. 6 The following is preferable in that it improves the processability of the composition: (A1) The weight-average molecular weight of the polymer is more preferably 1.1 × 10 5 The above, and more preferably 1.2 × 10 5 That concludes the explanation. Furthermore, the weight-average molecular weight of polymer (A1) is more preferably 1.5 × 10⁻⁶. 6 The following, and more preferably 1.2 × 10 6 The following applies. In this specification, the weight-average molecular weight of the polymer is the polystyrene equivalent value measured by gel permeation chromatography (hereinafter also referred to as "GPC"), and represents the weight-average molecular weight (total weight-average molecular weight) based on all peaks.

[0050] From the viewpoint of obtaining a crosslinked material with excellent grip performance on ice and rolling resistance, the glass transition temperature (Tg) of the (A1) polymer is -40°C or lower, preferably -42°C or lower, more preferably -45°C or lower, and even more preferably -46°C or lower. Furthermore, from the viewpoint of obtaining a crosslinked material with high strength and high wear resistance, the Tg of the (A1) polymer is preferably -70°C or higher. In this specification, the Tg of the polymer is the value measured by a differential scanning calorimetry (DSC) device in accordance with ASTM D3418.

[0051] Here, by increasing the Tg of the high-hydrogenation-rate conjugated diene polymer blended into the polymer composition, the processability during kneading of the polymer composition can be improved, and the handling of the polymer composition in the manufacturing process can be improved. On the other hand, if the Tg of the high-hydrogenation-rate conjugated diene polymer is increased, there is a concern that flexibility may be lost under usage conditions, limiting its application to winter tires, etc., and that rolling resistance may decrease. In this respect, this composition, which is blended with a specific liquid polymer along with a high-hydrogenation-rate conjugated diene polymer, is suitable because it has good processability during kneading of the polymer composition even when the Tg of the high-hydrogenation-rate conjugated diene polymer is low, and moreover, it is possible to obtain vulcanized rubber that exhibits high ice grip performance and excellent rolling resistance.

[0052] The composition may contain only the (A1) polymer as the (A) conjugated diene polymer, but may further contain a polymer different from the (A1) polymer, preferably an unhydrogenated conjugated diene polymer (hereinafter also referred to as "(A2) polymer"). Examples of (A2) polymers include natural rubber (NR), styrene-butadiene rubber (SBR), butadiene rubber (BR; for example, high-cis BR with 90% or more cis-1,4 bonds, syndiotactic-1,2-polybutadiene (SPB)-containing BR, etc.), isoprene rubber (IR), styrene-isoprene copolymer rubber, butadiene-isoprene copolymer rubber, etc. Of these, the (A2) polymer is preferably NR, BR, and SBR.

[0053] (A2) Polymers can be produced by the same method as described for polymer (A1), except that a hydrogenation reaction is not performed in the method for producing polymer (A1). The monomer units constituting polymer (A2), and the preferred ranges for the weight-average molecular weight, aromatic vinyl compound unit content, vinyl content, glass transition temperature, and other physical properties of polymer (A2) can be found in the description of polymer (A1).

[0054] From the viewpoint of obtaining a crosslinked material with excellent strength and abrasion resistance, the content of the (A1) polymer in this composition is preferably 50% by mass or more, relative to the total amount of the (A) conjugated diene polymer contained in this composition. From the above viewpoint, the content of the (A1) polymer is more preferably 60% by mass or more, even more preferably 70% by mass or more, and even more preferably 80% by mass or more, relative to the total amount of the (A) conjugated diene polymer.

[0055] Furthermore, the content of (A1) polymer is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more, relative to the total amount of rubber components in the polymer composition, from the viewpoint of ensuring the durability and abrasion resistance of the crosslinked material obtained from this composition. (A) Conjugated diene polymer can be used individually or in combination of two or more types.

[0056] In this specification, the "rubber component" contained in the polymer composition refers to a polymer from which a cured product exhibiting rubber elasticity can be obtained by thermosetting. This cured product exhibits the property of undergoing large deformation with a small force at room temperature (for example, deformation that causes it to stretch to more than twice its original size when stretched at room temperature), and rapidly returning to almost its original shape when the force is removed. In this specification, (B) liquid polymer is a component separate from the rubber component.

[0057] <(B) Liquid polymer> The liquid polymer (B) incorporated into this composition is a polymer that is fluid at room temperature (23°C). Preferably, the liquid polymer (B) is a liquid polymer having structural units derived from unsaturated hydrocarbon monomers. The liquid polymers (B) include polybutadiene, polyisoprene, polyisobutylene, polybutene, styrene-butadiene copolymers with a styrene content of 20% by mass or less, styrene-isoprene copolymers, butadiene-isoprene copolymers, isoprene-butadiene-styrene copolymers, ethylene-α-olefin copolymers, ethylene-propylene-diene copolymers, and polyfarnesene. These liquid polymers may be hydrogenated.

[0058] In other words, the composition comprises (B) a liquid polymer, at least one selected from the group consisting of polybutadiene and its hydrogenated derivatives, polyisoprene and its hydrogenated derivatives, styrene-butadiene copolymer and its hydrogenated derivatives having a styrene content of 20% by mass or less, styrene-isoprene copolymer and its hydrogenated derivatives, butadiene-isoprene copolymer and its hydrogenated derivatives, isoprene-butadiene-styrene copolymer and its hydrogenated derivatives, polyisobutylene, polybutene, ethylene-α-olefin copolymer, ethylene-propylene-diene copolymer, and polyfarnesene. These liquid polymers may be modified forms having at least one functional group selected from the group consisting of an amino group, a nitrogen-containing heterocyclic group, a phosphino group, a hydroxyl group, a carboxyl group, an acid anhydride group, a thiol group, and a hydrocarbyloxysilyl group.

[0059] (B) When the liquid polymer is a modified product, examples of the liquid polymer (B) include maleic anhydride-modified polybutadiene, maleic anhydride-modified polybutadiene, hydroxyl-terminated polybutadiene, carboxyl-terminated polybutadiene, hydroxyl / carboxyl-terminated polybutadiene, and polymers obtained by modifying the polymer shown as (B) liquid polymer in the same manner as the polymer (A1). Such modified polymers can be obtained, for example, by synthesis using a modifying agent having one or more functional groups selected from the group consisting of amino groups (protected primary amino groups, protected secondary amino groups, or tertiary amino groups), nitrogen-containing heterocyclic groups, phosphino groups, protected hydroxyl groups, protected carboxyl groups, acid anhydride groups, protected thiol groups, and hydrocarbyloxysilyl groups.

[0060] (B) The molecular weight of the liquid polymer is not particularly limited, but for example, the number average molecular weight (Mn) is preferably 600 or more, and more preferably 700 or more. Furthermore, the Mn of the liquid polymer (B) is preferably 50,000 or less, more preferably 40,000 or less, and even more preferably 30,000 or less.

[0061] These (B) liquid polymers can be obtained commercially. Commercially available liquid polymers (B) used in the preparation of this composition include, by product name: LIR-30, LIR-50, LIR-310, LIR-390, LIR-403, LIR-102M, LIR-290, LBR-302, LBR-302, LBR-307, LBR-352, LBR-352, L-SBR-820, L-SBR-841 (all manufactured by Kuraray Co., Ltd.), NISSO-PB B-1000, NISSO-PB B-2000, NISSO-PB B-3000, NISSO-PB G-1000, NISSO-PB G-2000, NISSO-PB G-3000, NISSO-PB BI-2000, NISSO-PB BI-3000, NISSO-PB JP-200, NISSO-PB Examples include GQ-1000 (manufactured by Nippon Soda Co., Ltd.), HV-35 (manufactured by ENEOS Corporation), Lucant series (manufactured by Mitsui Chemicals, Inc.), Ricon130, Ricon131, Ricon150, Ricon130MA8, Ricon130MA13, Krasol LBH2000, Krasol LBH-P2000, Krasol LBH3000, Krasol LBH-P3000 (all manufactured by Clay Valley Corporation). (B) As liquid polymers, one type can be used alone or two or more types can be used in combination.

[0062] (B) Among the liquid polymers, liquid polymers that do not have styrene units are preferred in that they can enhance the effect of improving the low fuel consumption performance of the crosslinked body obtained from this composition. Specifically, at least one selected from the group consisting of polybutadiene, polyisoprene, polyisobutylene, polybutene, butadiene-isoprene copolymer, ethylene-α-olefin copolymer, ethylene-propylene-diene copolymer, hydrogenated polybutadiene, hydrogenated polyisoprene, and hydrogenated butadiene-isoprene copolymer is preferred.

[0063] The content of (B) liquid polymer in this composition is not particularly limited as long as the effects of this disclosure are obtained. Preferably, the content of (B) liquid polymer is 1 part by mass or more per 100 parts by mass of (A) conjugated diene polymer contained in this composition. When the content of (B) liquid polymer is within the above range, it is preferable that a crosslinked body exhibiting good ice grip performance can be obtained, and a polymer composition with good processability can be obtained. From this viewpoint, the content of (B) liquid polymer is more preferably 2 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of (A) conjugated diene polymer. Furthermore, from the viewpoint of suppressing a decrease in the strength and abrasion resistance of the crosslinked body, the content of (B) liquid polymer is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 35 parts by mass or less, even more preferably 30 parts by mass or less, and particularly preferably 20 parts by mass or less, per 100 parts by mass of the total amount of (A) conjugated diene polymer.

[0064] <Other ingredients> In addition to (A) a conjugated diene polymer and (B) a liquid polymer, this composition may further contain the following components.

[0065] ·(C) Water-soluble components This composition may further contain at least one selected from the group consisting of water-soluble particles and water-soluble fibers (hereinafter also referred to as "(C) water-soluble component"). This composition is preferable in that the inclusion of the (C) water-soluble component can further improve ice grip performance. The (C) water-soluble component is not particularly limited as long as it is soluble or swellable in water at room temperature, but for example, a substance having a solubility of 1.2 g / 100 g-H2O or more in water at 25°C can be used.

[0066] Examples of water-soluble particles include water-soluble inorganic particles and organic particles. Among these, water-soluble inorganic particles include, for example, chlorides such as sodium chloride, potassium chloride, and magnesium chloride; sulfides such as sodium sulfate, potassium sulfate, and magnesium sulfate; carbonates such as sodium carbonate and sodium bicarbonate; phosphates such as sodium hydrogen phosphate; and hydroxides such as sodium hydroxide and potassium hydroxide.

[0067] Examples of water-soluble organic particles include lignin sulfonates such as sodium lignin sulfonate, potassium lignin sulfonate, calcium lignin sulfonate, magnesium lignin sulfonate, and ammonium lignin sulfonate; resins such as polyvinyl alcohol or its derivatives (e.g., partially acetic acid oxides, carboxylic acid-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, etc.), alkali salts of poly(meth)acrylate, and alkali salts of (meth)acrylic acid / (meth)acrylic acid ester copolymers; and sugars such as monosaccharides, oligosaccharides, and polysaccharides.

[0068] Specific examples of sugars include monosaccharides such as glucose, fructose, and galactose; oligosaccharides such as sucrose, lactose, maltose, raffinose, maltotriose, trehalose, and palatinose; and polysaccharides such as starch, dextrin, glycogen, glucan, xanthan gum, galactomannan (guar gum, fenugreek gum, etc.), cyclodextrins (α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, etc.), methylcellulose, ethylcellulose, and carboxymethylcellulose. As water-soluble particles, one of these can be used alone or in combination of two or more.

[0069] Water-soluble particles can be used in various forms such as powder, granules, or microbeads. (B) The water-soluble particles used as the water-soluble component are preferably solid water-soluble particles. From the viewpoint of obtaining sufficient improvement in ice grip performance, the median particle size of the water-soluble particles is preferably 1 μm or more, and more preferably 2 μm or more. Furthermore, from the viewpoint of achieving a good balance between ice grip performance and wear resistance, the median particle size is preferably 1000 μm or less, and more preferably 500 μm or less. In this specification, the median particle size of the water-soluble particles is the median diameter (D50), which is a value measured by laser diffraction and scattering.

[0070] As the water-soluble fiber, short fibers that can dissolve or swell in water can be used. Specifically, from the viewpoint of obtaining sufficient improvement in ice grip performance, the fiber length of the water-soluble fiber is preferably 1 mm or more, more preferably 2 mm or more, and even more preferably 4 mm or more. Furthermore, from the viewpoint of suppressing a decrease in abrasion resistance and processability, the fiber length is preferably 30 mm or less, more preferably 20 mm or less, and even more preferably 15 mm or less. The diameter (average diameter) of the water-soluble fiber is preferably 5 μm or more, more preferably 10 μm or more. Furthermore, the average diameter of the water-soluble fiber is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less.

[0071] Examples of water-soluble fibers include fibers whose main component is the substance exemplified in the description of water-soluble organic particles. Among these, at least one selected from the group consisting of polyvinyl alcohol-based fibers and polysaccharide fibers is preferably used. One of these water-soluble fibers may be used alone, or two or more may be used in combination.

[0072] The content of the water-soluble component (C) in this composition is not particularly limited as long as the effects of this disclosure are obtained, but it is preferably 0.1 parts by mass or more and 40 parts by mass or less per 100 parts by mass of the conjugated diene polymer (A). When the content of the water-soluble component (C) is within the above range, it is preferable in that a vulcanized rubber can be obtained that exhibits good ice grip performance while ensuring abrasion resistance. From this viewpoint, the content of the water-soluble component (C) is more preferably 0.5 parts by mass or more, and even more preferably 1 part by mass or more, per 100 parts by mass of the conjugated diene polymer (A). Furthermore, from the viewpoint of suppressing a decrease in the abrasion resistance of the crosslinked body, the content of the water-soluble component (C) is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, even more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, per 100 parts by mass of the conjugated diene polymer (A).

[0073] • Other rubber components The composition may contain only (A) conjugated diene polymer as the rubber component, but may also contain, in addition to (A) conjugated diene polymer, other rubber components (hereinafter also referred to as "other rubber components") that are different from (A) conjugated diene polymer, to the extent that they do not impair the effects of the disclosure. The type of such other rubber components is not particularly limited, but examples include halogenated butyl rubber. The amount of other rubber components blended is preferably 60% by mass or less, and more preferably 40% by mass or less, based on the total amount of rubber components ((A) conjugated diene polymer and other rubber components) contained in the polymer composition.

[0074] • Silica, etc. This composition preferably contains at least one selected from the group consisting of silica and carbon black (hereinafter also referred to as "silica, etc."). Silica is preferred in that it provides a static-to-dynamic ratio and good low hysteresis loss characteristics, while carbon black is preferred in that it has a high effect in improving the strength of the polymer composition and vulcanized rubber. Examples of silica include wet silica (hydrated silica), dry silica (anhydrous silica), colloidal silica, etc., with wet silica being preferred. Examples of carbon black include furnace black, acetylene black, thermal black, channel black, graphite, etc., with furnace black being preferred.

[0075] In this composition, the total amount of silica and carbon black is preferably 40 to 150 parts by mass per 100 parts by mass of the rubber component contained in the polymer composition. A silica content of 40 parts by mass or more is preferable because it sufficiently improves the strength of the vulcanized rubber. Furthermore, a silica content of 150 parts by mass or less is preferable because it ensures sufficient abrasion resistance of the vulcanized rubber. The silica content is preferably 50 parts by mass or more, more preferably 55 parts by mass or more, per 100 parts by mass of the total rubber component. Also, the silica content is preferably 150 parts by mass or less, more preferably 140 parts by mass or less, per 100 parts by mass of the total rubber component.

[0076] • Crosslinking agent This composition preferably contains a crosslinking agent. The type of crosslinking agent used is not particularly limited. Specific examples of crosslinking agents include organic peroxides, phenolic resins, sulfur, sulfur compounds, p-quinones, derivatives of p-quinone dioxime, bismaleimide compounds, epoxy compounds, silane compounds, amino resins, polyols, polyamines, triazine compounds, and metal soaps. Of these, it is preferable to use at least one crosslinking agent selected from the group consisting of organic peroxides, phenolic resins, and sulfur. The crosslinking agent can be used alone or in combination of two or more.

[0077] Examples of organic peroxides include 1,3-bis(t-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexine-3, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexene-3, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, 2,2'-bis(t-butylperoxy)-p-isopropylbenzene, dicumyl peroxide, di-t-butyl peroxide, and t-butyl peroxide.

[0078] Examples of phenolic resins include p-substituted phenolic compounds represented by the following formula (7), o-substituted phenol-aldehyde condensates, m-substituted phenol-aldehyde condensates, and brominated alkylphenol-aldehyde condensates. Among these, p-substituted phenolic compounds are preferred. P-substituted phenolic compounds can be obtained by a condensation reaction between a p-substituted phenol and an aldehyde (preferably formaldehyde) in the presence of an alkaline catalyst. [ka] (In formula (7), X is a hydroxyl group, an alkyl halide, or a halogen atom. R is a monovalent saturated hydrocarbon group having 1 to 15 carbon atoms. n is an integer from 0 to 10.)

[0079] Commercially available phenolic resins include: product name "Tackiroll 201" (alkylphenol formaldehyde resin, manufactured by Taoka Chemical Industry Co., Ltd.), product name "Tackiroll 250-I" (brominated alkylphenol formaldehyde resin with a bromination rate of 4%, manufactured by Taoka Chemical Industry Co., Ltd.), product name "Tackiroll 250-III" (brominated alkylphenol formaldehyde resin, manufactured by Taoka Chemical Industry Co., Ltd.), and product name "PR-4507" (group Examples include: ST137X (manufactured by Rohm & Haas), Sumilight Resin PR-22193 (manufactured by Sumitomo Durez), Tamanol 531 (manufactured by Arakawa Chemical Industries), SP1059, SP1045, SP1055, SP1056 (all manufactured by Schenectady), and CRM-0803 (manufactured by Showa Union Synthetic Co.). Among these, Tackiroll 201 can be preferably used.

[0080] The amount of crosslinking agent added is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, and even more preferably 0.5 to 10 parts by mass, based on 100 parts by mass of the total amount of rubber components in the polymer composition.

[0081] • Resin components This composition may further contain resin components (except for (B) liquid polymers) along with the rubber components. The type of resin component is not particularly limited, but examples include polyethylene, polypropylene, and other polyolefin resins. When resin components are added, the amount added is preferably 1 to 50 parts by mass, more preferably 5 to 40 parts by mass, based on 100 parts by mass of the total amount of rubber components contained in the polymer composition.

[0082] In addition to the components described above, this composition may contain various additives commonly used in polymer compositions for obtaining vulcanized rubber for various applications such as tires, hoses, vibration damping, and belts. Examples of such additives include antioxidants, zinc oxide, stearic acid, softeners, sulfur, and vulcanization accelerators. The amount of each of these additives can be appropriately selected depending on the type of additive, as long as it does not impair the effects of this disclosure.

[0083] <Bridged structures and tires> The crosslinked material of this disclosure can be obtained by crosslinking the above-mentioned polymer composition. When obtaining a rubber molded product as a crosslinked material, the polymer composition is usually molded into a predetermined shape before the crosslinking treatment is performed. The rubber molded product can be manufactured according to conventional methods. For example, in the manufacture of a tire, the above-mentioned polymer composition is mixed in a mixer such as a roll or mixer, molded into a predetermined shape, and then placed in a predetermined position according to conventional methods and vulcanized. This forms one or both of the tread and sidewall, and a pneumatic tire can be obtained.

[0084] The crosslinked material (specifically vulcanized rubber) of this disclosure has excellent mechanical strength and can be applied to various rubber molded products. Specifically, it can be used as a material for tire treads and sidewalls; rolls and vibration-damping rubber for industrial machinery and equipment; various hoses and hose covers such as diaphragms, radiator hoses, and air hoses; seals such as packings, gaskets, weatherstrips, O-rings, and oil seals; belts such as power transmission belts; and materials for linings, dust boots, wire harnesses, and shoe soles. Among these, it is particularly suitable as a tire component, vibration-damping component, belt component, roll component, hose component, wire harness component, and shoe sole component, and is even more suitable as a tire component, vibration-damping component, roll component, and belt component.

[0085] Furthermore, the crosslinked material of this disclosure exhibits high strength and high wear resistance, as well as excellent ice grip performance and rolling resistance, making it particularly suitable for tire components, and especially suitable for winter tires and all-season tires. In particular, it is suitable as a material for one or both of the tire tread and sidewall. [Examples]

[0086] The present disclosure will be described below in detail based on examples, but this disclosure is not limited to these examples. In the examples and comparative examples, "parts" and "%" refer to mass unless otherwise specified. The methods for measuring various physical properties are shown below.

[0087] [Styrene content (mass%)]: 400MHz 1 This was determined using a 1H-NMR spectrometer. [Vinyl content (mol%)]: 400MHz 1 This was determined using a 1H-NMR spectrometer. [Hydrogenation rate (%)] and [θ]: 500MHz 1 This was determined using a 1H-NMR spectrometer. [1st peak molecular weight]: This was determined in polystyrene equivalent from the retention time corresponding to the peak of the maximum peak of the GPC curve obtained using a gel permeation chromatograph (HLC-8120GPC (product name), manufactured by Tosoh Corporation) under the following measurement conditions. [Total weight-average molecular weight]: This was determined from the GPC curve obtained using a gel permeation chromatograph (HLC-8120GPC (product name), manufactured by Tosoh Corporation) under the following measurement conditions, and converted to polystyrene equivalent. (GPC measurement conditions) Columns; Product name "GMHXL" (manufactured by Tosoh Corporation), 2 pieces Column temperature: 40°C Mobile phase; tetrahydrofuran Flow rate; 1.0ml / min Sample concentration: 10 mg / 20 ml [Glass transition temperature Tg (°C)]: Measured using a differential scanning calorimetry (DSC) instrument in accordance with ASTM D3418.

[0088] <Manufacturing of Hydrogenated Catalysts> [Synthesis of catalyst E] A 1 L three-necked flask equipped with a stirrer and dropping funnel was purged with dry nitrogen, and 200 ml of anhydrous tetrahydrofuran and 0.2 moles of tetrahydrofurfuryl alcohol were added. Then, n-butyllithium / cyclohexane solution (0.2 moles) was added dropwise to the three-necked flask at 15°C to carry out the reaction and obtain a tetrahydrofuran solution of tetrahydrofurfuryloxylithium. Next, a 1 L three-necked flask equipped with a stirrer and dropping funnel was purged with dry nitrogen, and 49.8 g (0.2 mol) of bis(η5-cyclopentadienyl)titanium dichloride and 250 ml of anhydrous tetrahydrofuran were added. Then, the tetrahydrofuran solution of tetrafurfuryloxylithium obtained by the method described above was added dropwise over approximately 1 hour at room temperature while stirring. After approximately 2 hours, the reddish-brown liquid was filtered, and the insoluble portion was washed with dichloromethane. Subsequently, the filtrate and washing solution were combined and the solvent was removed under reduced pressure to obtain catalyst E [bis(η5-cyclopentadienyl)titanium(tetrahydrofurfuryloxy)chloride] (also known as "[chlorobis(2,4-cyclopentadienyl)titanium(IV)tetrahydrofurfurylalkoxide]"). The yield was 95%.

[0089] <Production of conjugated diene polymers> [Production Example 1: Synthesis of Conjugated Diene Polymer A-1] 25,900 g of cyclohexane, 26 g of tetrahydrofuran, 1,273 g of styrene, and 2,361 g of 1,3-butadiene were charged into a nitrogen-purged autoclave reactor with an internal volume of 50 liters. After adjusting the temperature of the reactor contents to 45°C, polymerization was started by adding a cyclohexane solution containing n-butyllithium (39 mmol). Polymerization was carried out under adiabatic conditions, and the maximum temperature reached 80°C. After confirming that the polymerization conversion rate reached 99%, 111 g of butadiene was added and polymerization was carried out for a further 5 minutes to obtain a reaction solution containing the polymer. 2 mmol of silicon tetrachloride was added to the obtained reaction solution and reacted for 10 minutes, and then 28 mmol of N,N-dimethyl-3-(triethoxysilyl)propylamine was added and reacted for 20 minutes. Next, the reaction mixture was heated to over 80°C to introduce hydrogen into the system. Then, 3.2 g of diethylaluminum chloride, 2.4 g of catalyst E, and n-butyllithium (15 mmol) were added. Hydrogen was supplied while maintaining a hydrogen pressure of 0.7 MPa or higher until the predetermined hydrogen cumulative value was reached, and the hydrogenation reaction was carried out. After that, the reaction mixture was returned to room temperature and atmospheric pressure and withdrawn from the reaction vessel to obtain a polymer solution containing a hydrogenated conjugated diene polymer. To the obtained polymer solution, 1.4 g of 2,6-di-tert-butyl-p-cresol was added. Next, an aqueous solution (temperature: 80°C) adjusted to pH 8.5 (pH at 80°C by glass electrode method) with ammonia as a pH adjusting agent was placed in a desolvation tank, and the above polymer solution was further added (1000 parts by mass of the aqueous solution to 100 parts by mass of the polymer solution). Desolvation was performed by steam stripping (steam temperature: 190°C) at a liquid phase temperature of 95°C in the desolvation tank for 2 hours, and drying was performed using a heated roller heated to 110°C to obtain conjugated diene polymer A-1. The analytical values ​​of the obtained conjugated diene polymer A-1 are shown in Table 2. The 1st peak molecular weight of conjugated diene polymer A-1 is 20 × 10⁶ 4 The weight-average molecular weight (total weight-average molecular weight) is 34 × 10⁻⁶. 4 The hydrogenation rate was 93% (θ=0.93), and the glass transition temperature was -34°C.

[0090] [Production Examples 2-7, 9: Synthesis of conjugated diene polymers A-2-A-7, A-9] Polymerization was carried out in the same manner as in Production Example 1, except that the raw materials used were changed as shown in Table 1 and the amount of hydrogen supplied was changed, to obtain conjugated diene polymers A-2 to A-7 and A-9, respectively. The analytical values ​​of conjugated diene polymers A-2 to A-7 and A-9 are shown in Table 2.

[0091] [Production Example 8: Synthesis of Conjugated Diene Polymer A-8] 25,900 g of cyclohexane, 26 g of tetrahydrofuran, 1,273 g of styrene, and 2,361 g of 1,3-butadiene were charged into a nitrogen-purged autoclave reactor with an internal volume of 50 liters. After adjusting the temperature of the reactor contents to 45°C, polymerization was started by adding a cyclohexane solution containing n-butyllithium (39 mmol). Polymerization was carried out under adiabatic conditions, and the maximum temperature reached 80°C. After confirming that the polymerization conversion rate reached 99%, 111 g of butadiene was added and polymerization was carried out for a further 5 minutes to obtain a reaction solution containing the polymer. 2 mmol of silicon tetrachloride was added to the obtained reaction solution and reacted for 10 minutes, and then 28 mmol of N,N-dimethyl-3-(triethoxysilyl)propylamine was added and reacted for 20 minutes. Next, the reaction solution was heated to over 80°C to introduce hydrogen into the system, and then the reaction solution was returned to room temperature and atmospheric pressure and withdrawn from the reaction vessel to obtain a polymer solution containing the conjugated diene copolymer. To the obtained polymer solution, 1.4 g of 2,6-di-tert-butyl-p-cresol was added. Next, an aqueous solution (temperature: 80°C) adjusted to pH 8.5 (pH at 80°C by the glass electrode method) with ammonia as a pH adjusting agent was placed in a desolvation tank, and the above polymer solution was further added (1000 parts by mass of the aqueous solution to 100 parts by mass of the polymer solution). Desolvation was performed by steam stripping (steam temperature: 190°C) at a liquid phase temperature of 95°C in the desolvation tank for 2 hours, and drying was performed using a heated roller heated to 110°C to obtain the conjugated diene polymer A-8. The first peak molecular weight of the obtained conjugated diene polymer A-8 was 20 × 10⁶. 4 The weight-average molecular weight (total weight-average molecular weight) is 34 × 10⁻⁶. 4 The glass transition temperature was -40°C. The conjugated diene polymer A-8 had a hydrogenation rate of 0% and θ = 0.

[0092] [Table 1]

[0093] In Table 1, the abbreviations for the compounds represent the following compounds. Compound A: Piperidine Compound B: N,N-dimethyl-3-(triethoxysilyl)propylamine Compound C: Silicon tetrachloride In Table 1, "-" indicates that the compound in the corresponding column was not used.

[0094] [Table 2]

[0095] <Manufacturing and Characterization of Polymer Compositions> [Examples 1-16 and Comparative Examples 1-7] Using a Plastmill (capacity 250cc) equipped with a temperature control device, the first stage of mixing involved kneading a conjugated diene polymer, liquid polymer, silica, silane coupling agent, spreading oil, stearic acid, zinc oxide, and antioxidant at a filling rate of 72% and a rotation speed of 60 rpm, according to the formulations shown in Tables 3 and 4. Next, in the second stage of mixing, after cooling the mixture obtained above to room temperature, the (C) water-soluble component, sulfur, and vulcanization accelerator were kneaded according to the formulations shown in Tables 3 and 4. This mixture was then molded and vulcanized at 160°C for a predetermined time using a vulcanization press. The following property evaluations (1) to (5) were performed using the vulcanized rubber. The types and proportions of the conjugated diene polymer, liquid polymer, and (C) water-soluble component used in each example and comparative example are as shown in Tables 3 and 4. In Comparative Examples 1 and 2, solid polyisoprene rubber at room temperature was used instead of the liquid polymer. The values ​​in Tables 3 and 4 represent the proportion (parts by mass) of each component.

[0096] ≪Characteristics Evaluation≫ (1) Rubber cohesion test during the process (evaluation of processability) After observing the shape of the polymer composition after kneading in a plastmill according to the formulation of each example and comparative example, the composition was wound onto a 6-inch open roll with the surface temperature adjusted to 60°C, and the moldability was evaluated based on the state of winding onto the roll. The evaluation was conducted using a three-level sensory evaluation, with Comparative Example 2 rated as "B". The evaluation criteria are as follows. A: After kneading in a plastmill, more than 80% of the total mass of the polymer composition pieces was discharged in lumps. The polymer composition pieces were sticky from the initial stage of being fed into the roll and wrapped around the roll. Roll processability and moldability were extremely good. B: After kneading in a plastmill, approximately half to 80% of the total mass of the polymer composition was discharged in lumps. The polymer composition did not wrap around the rolls initially, but gradually wrapped around them. There were no major problems with roll processing and molding. C: After kneading in a plastmill, more than half of the total mass of the polymer composition pieces was discharged in powder form. The polymer composition pieces had low tackiness even after being fed into the rolls and did not wrap around the rolls. Roll processing and molding were difficult.

[0097] (2) Tensile strength Tensile tests were performed on vulcanized rubber samples in accordance with JIS K6251:2010. A dumbbell-shaped sample (Type 3) was used, and the stress at fracture (TB) and elongation at fracture (EB) were measured at room temperature. Higher TB and EB values ​​indicate greater fracture strength and superior mechanical strength of the material. Evaluation was based on the TB value, and the results are shown using normalized values ​​so that the TB value for Comparative Example 2 is 100. (3) Abrasion resistance Vulcanized rubber was used as the measurement sample, and measurements were taken using a DIN abrasion tester (manufactured by Toyo Seiki Co., Ltd.) in accordance with JIS K6264-2:2005, under a load of 10N at 25°C. The values ​​are expressed as normalized values ​​so that the value for Comparative Example 2 becomes 100, and a higher value indicates better abrasion resistance.

[0098] (4) Ice grip performance A vulcanized rubber sample with a diameter of 50 mm and a thickness of 10 mm was used for measurement. It was pressed onto a fixed ice surface, and the surface pressure was set to 12 kgf / cm² in a -2°C environment. 2 The frictional force generated when the sample was rotated at a main rotation speed of 20 cm / second was detected using a load cell, and the coefficient of dynamic friction μ was calculated. The evaluation was performed using the coefficient of dynamic friction μ, and the results are shown using values ​​normalized so that the coefficient of dynamic friction μ of Comparative Example 2 becomes 100.

[0099] (5) Change in hardness (Δ hardness) For each test specimen consisting of vulcanized rubber sheets before and after heat aging, the hardness (Duro-A hardness) was measured in accordance with JIS K6253, and the change over time was evaluated based on the difference in hardness before and after heat aging. The evaluation was performed in three stages: "A" for a difference of less than 3 in hardness before and after heat aging, "B" for 3 or more but less than 6, and "C" for 6 or more. Here, "heat aging" refers to the process of obtaining heat-aged vulcanized rubber by performing heat aging (100°C, 70 hours) on new vulcanized rubber in accordance with JIS K6257:2010.

[0100] (6) Rolling resistance (50℃ tanδ) Cross-linked rubber was used as the measurement sample, and measurements were taken using an ARES-RDA (manufactured by TA Instruments) under the conditions of shear strain of 0.7%, angular velocity of 100 radians per second, and temperature of 50°C. The measurement results are shown as an index with Comparative Example 2 set to 100, and a higher value indicates smaller energy loss and better rolling resistance (low fuel consumption performance). The results of the characterization evaluations for Examples 1-16 and Comparative Examples 1-7 are shown in Tables 3 and 4.

[0101] [Table 3]

[0102] [Table 4]

[0103] The details of each component in Tables 3 and 4 are as follows: B-0: Polyisoprene rubber, product name "IR2200", manufactured by JSR Corporation. B-1: Liquid polyisoprene, product name "LIR-30", manufactured by Kuraray Co., Ltd. B-2: Liquid polybutadiene, product name "NISSO-PB B-3000", manufactured by Nippon Soda Co., Ltd. B-3: Liquid hydrogenated polybutadiene, product name "NISSO-PB BI-3000", manufactured by Nippon Soda Co., Ltd. B-4: End-modified liquid butadiene, product name "NISSO-PB G-3000", manufactured by Nippon Soda Co., Ltd. B-5: Polybutene, product name "HV-35", manufactured by ENEOS Corporation. B-6: Ethylene olefin co-oligomer, product name "HC40", manufactured by Mitsui Chemicals, Inc. B-7: Ethylene olefin co-oligomer, product name "HC600", manufactured by Mitsui Chemicals, Inc. B-8: Liquid styrene-butadiene rubber (styrene content: 25% by mass), product name "RICON100", manufactured by CRAY VALLEY. C-1: Magnesium sulfate, product name "MN-00", manufactured by Maiko Chemical Industries Co., Ltd. C-2: Polyvinyl alcohol short fiber, product name "Kuralon 1239", manufactured by Kuraray Co., Ltd. C-3: Sodium ligninsulfonate, manufactured by Tokyo Chemical Industry Co., Ltd. Note that B-1 to B-8 are liquid polymers. C-1 to C-3 correspond to (C) water-soluble components.

[0104] The details of each component used in Tables 3 and 4 (*1) to *7) are as follows. *1) Rhodia ZEOSIL 1165MP *2) Manufactured by Mitsubishi Chemical Corporation, Diablack N339 *3) Evonik Si75 *4) Process oil T-DAE manufactured by JX Nippon Oil & Energy Corporation *5) Ozonon 6C manufactured by Seiko Chemical Co., Ltd. *6) Noxellar CZ-G manufactured by Ouchi Shinko Chemical Industry Co., Ltd. *7) Noxellar D, manufactured by Ouchi Shinko Chemical Industry Co., Ltd. In Tables 3 and 4, the numbers in parentheses represent the amount (parts by mass) of the polymer when it was prepared.

[0105] As shown in Tables 3 and 4, polymer compositions (Examples 1-16) containing (A) a polymer (A1) with a hydrogenation rate of 75% or more as a conjugated diene polymer and a specific liquid polymer showed sufficiently high values ​​(indices) for tensile strength, abrasion resistance, ice grip performance, and rolling resistance, and exhibited good rubber cohesion during the manufacturing process (i.e., good processability during rubber compounding), demonstrating a good balance of various properties. Furthermore, Examples 1-16 showed little hardness change, and performance degradation over time was suppressed. In addition, polymer compositions (Examples 13-15) further containing (C) a water-soluble component showed further improved ice grip performance compared to Example 3, which did not contain the (C) water-soluble component.

[0106] Furthermore, in Example 7, which used a hydrogenated polymer as the liquid polymer, the tensile strength, abrasion resistance, and rolling resistance of the rubber were further improved compared to Example 6, which used an unhydrogenated liquid polymer.

[0107] In contrast, Comparative Example 1, which contained polymer (A1) but not liquid polymer, had poor rubber cohesion during the process and received a processability rating of "C". Furthermore, Comparative Examples 2 and 3, which used a conjugated diene polymer with a hydrogenation rate of 0% and a glass transition temperature of -40°C, and Comparative Example 4, which used a conjugated diene polymer with a hydrogenation rate of 60% and a glass transition temperature of -33°C, showed significantly lower tensile strength and abrasion resistance compared to Examples 1 to 16, and also exhibited inferior ice grip performance. In addition, Comparative Example 5, which used a conjugated diene polymer with a glass transition temperature of -34°C, and Comparative Example 6, which used a conjugated diene polymer with a glass transition temperature of -28°C, exhibited inferior ice grip performance and rolling resistance compared to Examples 1 to 16. Comparative Example 7, which used liquid styrene-butadiene rubber with a styrene content of 25% by mass as component B, exhibited inferior rolling resistance compared to Examples 1 to 16.

[0108] From the above results, it was revealed that a polymer composition containing polymer (A1) and a specific liquid polymer maintains high tensile strength and abrasion resistance, exhibits good rubber cohesion and processability during the mixing of the polymer composition, improves ice grip performance and rolling resistance, and suppresses performance degradation over time.

Claims

1. (A) Conjugated diene polymers, and (B) Liquid polymer, It contains, The (A) conjugated diene polymer includes a polymer (A1) which satisfies the condition of the following formula (i) when the constituent ratios (molar ratios) of the structural units represented by the following formula (1), the following formula (2), the following formula (3), and the following formula (4) in the polymer are p, q, r, and s, respectively. The glass transition temperature of the polymer (A1) is -40°C or lower. The liquid polymer (B) is a liquid polymer that does not have styrene units, and is at least one selected from the group consisting of polybutadiene and its hydrogenated derivatives, polyisoprene and its hydrogenated derivatives, butadiene-isoprene copolymer and its hydrogenated derivatives, polyisobutylene, polybutene, ethylene-α-olefin copolymer, and ethylene-propylene-diene copolymer. Polymer composition. Formula (i): 0.75≦(p+(0.5×r)) / (p+q+(0.5×r)+s)≦0.97 【Chemistry 1】

2. The polymer composition according to claim 1, wherein the proportion of the (A1) polymer in the (A) conjugated diene polymer is 50% by mass or more.

3. The weight-average molecular weight (Mw) of the polymer (A1) measured by gel permeation chromatography in terms of polystyrene is 1.0 × 10 ５ ~2.0 x 10 ６ The polymer composition according to claim 1 or 2.

4. The polymer composition according to any one of claims 1 to 3, wherein the polymer (A1) contains structural units derived from an aromatic vinyl compound in an amount of 3 to 45% by mass relative to the total amount of monomer units in the polymer (A1).

5. The polymer composition according to any one of claims 1 to 4, wherein the (A1) polymer has at least one functional group selected from the group consisting of an amino group, a nitrogen-containing heterocyclic group, a phosphino group, a hydroxyl group, a thiol group, and a hydrocarbyloxysilyl group.

6. The polymer composition according to any one of claims 1 to 5, wherein the (A1) polymer has a substructure derived from at least one compound selected from the group consisting of compounds represented by the following formula (5) and compounds represented by the following formula (6). 【Chemistry 2】 (In formula (5), A １ has at least one atom selected from the group consisting of nitrogen, phosphorus, oxygen, sulfur, and silicon, has no active hydrogen, and is a monovalent functional group bonded to R ５ via a nitrogen atom, a phosphorus atom, an oxygen atom, a sulfur atom, a silicon atom, or a carbon atom contained in a carbonyl group, or is a (thio) epoxy group. R ３ and R ４ are each independently a hydrocarbyl group. R ５ is a hydrocarbylene group. r is an integer from 0 to 2. However, when r is 2, the plurality of R ３ in the formula are the same as or different from each other. When r is 0 or 1, the plurality of R ４ in the formula are the same as or different from each other.) 【Transformation 3】 (In formula (6), A ２ It has at least one atom selected from the group consisting of nitrogen, phosphorus, oxygen, sulfur, and silicon, and does not have active hydrogen, and R ９ It is a monovalent functional group bonded to it by a nitrogen atom, phosphorus atom, oxygen atom, sulfur atom, or silicon atom, or a hydrocarbyl group having 1 to 20 carbon atoms. ６ and R ７ These are, independently, hydrocarbyl groups. ８ This is a hydrocarbylene group. ９ m is a single bond or a hydrocarbylene group. m is 0 or 1. However, if m is 0, multiple R in the formula ７ (They are either identical or different from each other.)

7. The polymer composition according to any one of claims 1 to 6, wherein the content of the liquid polymer (B) is 1 to 50 parts by mass per 100 parts by mass of the conjugated diene polymer (A).

8. The polymer composition according to any one of claims 1 to 7, wherein the liquid polymer (B) has at least one functional group selected from the group consisting of an amino group, a nitrogen-containing heterocyclic group, a phosphino group, a hydroxyl group, a carboxyl group, an acid anhydride group, a thiol group, and a hydrocarbyloxysilyl group.

9. (C) The polymer composition according to any one of claims 1 to 8, further comprising at least one component selected from the group consisting of water-soluble particles and water-soluble fibers.

10. The polymer composition according to any one of claims 1 to 9, further comprising at least one selected from the group consisting of silica and carbon black.

11. The polymer composition according to any one of claims 1 to 10, further containing a crosslinking agent.

12. A crosslinked body obtained using the polymer composition described in any one of claims 1 to 11.

13. A tire having one or both of the tread and sidewall formed using the polymer composition according to any one of claims 1 to 11.

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