Modified conjugated diene polymer and production method therefor, rubber bale, polymer composition, crosslinked product, and tire

Abstract

A modified conjugated diene polymer having a partial structure derived from a compound (M), which has a nitrogen atom and a hydrocarbyloxysilyl group in a single molecule, the modified conjugated diene polymer having a Mooney viscosity measured at 160°C of 80-150.

Description

Modified conjugated diene polymer and its manufacturing method, rubber veil, polymer composition, crosslinked product, and tire

[0001] [Cross-reference to related applications] This application claims priority to Japanese Patent Application No. 2023-163701, filed on September 26, 2023, the entire contents of which are incorporated herein by reference. The present disclosure relates to a modified conjugated diene-based polymer and a method for producing the same, a rubber veil, a polymer composition, a crosslinked product, and a tire.

[0002] Conjugated diene polymers obtained by polymerization using conjugated diene compounds have various excellent properties such as heat resistance, abrasion resistance, mechanical strength, and moldability, and are therefore widely used in various industrial products such as pneumatic tires, anti-vibration rubber, and hoses.

[0003] It is known that fillers such as carbon black and silica are blended with conjugated diene polymers in rubber compositions used for the treads, sidewalls, etc. of pneumatic tires to improve the durability and abrasion resistance of the products. Furthermore, it has been proposed to use modified conjugated diene polymers in which heteroatoms such as silicon, nitrogen, oxygen, sulfur, and phosphorus have been introduced into the conjugated diene polymers in order to increase the affinity between the conjugated diene polymers and the fillers (see, for example, Patent Documents 1 to 3).

[0004] International Publication No. 2008 / 123164 Japanese Patent Application Laid-Open No. 11-349632 International Publication No. 2017 / 221943

[0005] With the trend toward electrification and fuel efficiency in automobiles, rubber for automobile tires is required to have even lower rolling resistance, higher wear resistance, and higher strength than ever before.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and an object of the present disclosure is to provide a modified conjugated diene-based polymer from which a crosslinked product having an improved and well-balanced rolling resistance, abrasion resistance, and strength can be obtained.

[0007] According to one aspect of the present disclosure, there is provided a modified conjugated diene-based polymer having a partial structure derived from a compound (M) having a nitrogen atom and a hydrocarbyloxysilyl group in one molecule, and having a Mooney viscosity measured at 160°C of 80 or more and 150 or less.

[0008] According to the present disclosure, in another aspect, there is provided a method for producing the modified conjugated diene-based polymer, the method including: a step of polymerizing the monomers in a solvent in the presence of a polymerization initiator by a continuous polymerization system to obtain a polymer having an active end; a step of reacting the polymer having an active end with the compound (M) to obtain a polymer solution; and a step of removing the solvent from the polymer solution without adding an extender oil to the polymer solution.

[0009] According to another aspect of the present disclosure, there is provided a rubber veil containing the modified conjugated diene-based polymer and not containing an extender oil.

[0010] In another aspect, the present disclosure provides a polymer composition containing the modified conjugated diene polymer and at least one filler selected from the group consisting of silica, carbon black, and a compound represented by the following formula (1): １ mSiO ｋ ・iH ２ O...(1) (In formula (1), M １ is at least one selected from the group consisting of a specific metal selected from aluminum, magnesium, titanium, zirconium, and calcium, an oxide of the specific metal, a hydroxide of the specific metal, and a carbonate of the specific metal; n is an integer of 1 to 5, m is an integer of 0 to 10, k is an integer of 2 to 5, and i is an integer of 0 to 10.

[0011] According to another aspect of the present disclosure, there is provided a crosslinked body obtained by crosslinking the polymer composition, and a tire having a tread and / or a sidewall made using the polymer composition.

[0012] The modified conjugated diene-based polymer of the present disclosure can provide a crosslinked product with a well-balanced improvement in rolling resistance, abrasion resistance, and strength.

[0013] Matters relating to aspects of the present disclosure will be described in detail below. Note that the present invention is not limited to the embodiments described below, and should be understood to include various modifications implemented within the scope of the present invention. In this specification, a numerical range described as "X to Y" represents a numerical range including numerical value X as the lower limit and numerical value Y as the upper limit.

[0014] The term "(meth)acrylic acid" is a concept that includes both "acrylic acid" and "methacrylic acid." The term "(modified) conjugated diene polymer" is a term that includes both unmodified conjugated diene polymers and modified conjugated diene polymers (i.e., modified conjugated diene polymers). Hereinafter, when simply referred to as a "conjugated diene polymer," the "conjugated diene polymer" may be an unmodified conjugated diene polymer or a modified conjugated diene polymer, unless otherwise specified.

[0015] <Modified Conjugated Diene Polymer> The modified conjugated diene polymer of the present disclosure (hereinafter also referred to as "modified conjugated diene polymer (P)") has a structural unit derived from a conjugated diene compound and a partial structure derived from a compound (hereinafter also referred to as "compound (M)") having a nitrogen atom and a hydrocarbyloxysilyl group in one molecule. The modified conjugated diene polymer (P) has a Mooney viscosity measured at 160°C of 80 to 150.

[0016] <Conjugated diene compound> Examples of conjugated diene compounds 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, 1,3-butadiene, isoprene, and 2,3-dimethyl-1,3-butadiene are preferred. One type of conjugated diene compound may be used alone, or two or more types may be used in combination.

[0017] The modified conjugated diene polymer (P) may be a homopolymer of a conjugated diene compound, or may be a copolymer of a conjugated diene compound and a monomer other than the conjugated diene compound (hereinafter also referred to as "other monomer"). From the viewpoint of increasing the strength of a crosslinked body (i.e., rubber) obtained using the modified conjugated diene polymer (P), the modified conjugated diene polymer (P) is preferably a copolymer of a conjugated diene compound and an aromatic vinyl compound.

[0018] <Aromatic Vinyl Compounds> Examples of aromatic vinyl compounds include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, vinylethylbenzene, divinylbenzene, trivinylbenzene, divinylnaphthalene, t-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl)dimethylaminoethyl ether, N,N-dimethylaminoethylstyrene, N,N-dimethylaminomethylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2-t-butylstyrene, 3-t-butylstyrene, 4-t-butylstyrene, vinylxylene, vinylnaphthalene, vinylpyridine, diphenylethylene, and tertiary amino group-containing diphenylethylenes (e.g., 1-(4-N,N-dimethylaminophenyl)-1-phenylethylene). Among these, styrene or α-methylstyrene is preferred as the aromatic vinyl compound. The aromatic vinyl compounds may be used alone or in combination of two or more.

[0019] When the modified conjugated diene polymer (P) is a copolymer of a conjugated diene compound and an aromatic vinyl compound, it is preferably a copolymer containing 1,3-butadiene and styrene in the monomer composition, in terms of high living property in anionic polymerization. In terms of achieving a well-balanced improvement in hysteresis loss at low and high temperatures, the modified conjugated diene polymer (P) preferably has a random copolymerization portion in which the distribution of the conjugated diene compound and the aromatic vinyl compound is irregular. The modified conjugated diene polymer (P) may further have a block portion composed of a conjugated diene compound or an aromatic vinyl compound.

[0020] Examples of other monomers include aromatic vinyl compounds, as well as acrylonitrile, methyl (meth)acrylate, and ethyl (meth)acrylate.

[0021] <Molecular Structure> The molecular structure of the modified conjugated diene polymer is not particularly limited and may be linear or branched. Furthermore, the position at which the partial structure derived from the compound (M) is introduced into the modified conjugated diene polymer (P) is also not particularly limited. For example, the modified conjugated diene polymer (P) may have the partial structure derived from the compound (M) at one or both ends of the polymer, or may have it on a side chain. Furthermore, the modified conjugated diene polymer (P) may be a polymer having a plurality of polymer chains and a partial structure derived from the compound (M), with one end of each of the plurality of polymer chains bonded to the partial structure derived from the compound (M). In terms of being able to easily introduce the partial structure derived from the compound (M) into the polymer and having a high effect of improving rolling resistance, the modified conjugated diene polymer (P) preferably has a structure having a plurality of polymer chains and a partial structure derived from the compound (M), with one end of each of the plurality of polymer chains bonded to the partial structure derived from the compound (M).

[0022] <Compound (M)> The compound (M) may have a nitrogen atom and a hydrocarbyloxysilyl group in one molecule. Here, in this specification, the term "hydrocarbyloxysilyl group" refers to a monovalent or divalent group in which 1 to 3 hydrocarbyloxy groups are bonded to a silicon atom. That is, the hydrocarbyloxysilyl group is defined as "-Si(OR ２１ ) ３－ｗ (R ２０ ) ｗ " or ">Si(OR ２１ ) ２－ｙ (R ２０ ) ｙ ” (However, R ２０ and R ２１ are each independently a hydrocarbyl group, w is an integer of 0 to 2, and y is 0 or 1. For example, "-Si(OR ２１ ) ３" in one molecule and having a nitrogen-containing group is a "compound having a nitrogen-containing group and two hydrocarbyloxysilyl groups." The expression "having two or more hydrocarbyloxysilyl groups" does not indicate the number of hydrocarbyloxy groups bonded to the silicon atom.

[0023] The above "-Si(OR ２１ ) ３－ｗ (R ２０ ) ｗ " or a group represented by ">Si(OR ２１ ) ２－ｙ (R ２０ ) ｙ In the group represented by ", R ２０ or R ２１ Examples of the hydrocarbyl group represented by R include an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms. ２０ or R ２１ is preferably a linear or branched alkyl group having 1 to 20 carbon atoms, and more preferably a linear or branched alkyl group having 1 to 12 carbon atoms.

[0024] Compound (M) is preferably a modifying agent, specifically, an initiating end-modifying agent for introducing a partial structure containing a heteroatom into the initiating end of a polymer, or a terminal end-modifying agent for introducing a partial structure containing a heteroatom into the terminal end of a polymer. Herein, "modification" refers to imparting a partial structure containing a heteroatom such as nitrogen, oxygen, sulfur, phosphorus, or silicon to an unmodified conjugated diene polymer composed of structural units derived from hydrocarbons. Hereinafter, compound (M) as an initiating end-modifying agent will be referred to as "compound (M1)," and compound (M) as a terminal end-modifying agent will be referred to as "compound (M2)."

[0025] (Compound (M1)) As the compound (M1), a compound having one or more secondary amino groups and / or tertiary amino groups and one or more hydrocarbyloxysilyl groups can be preferably used. When a metal compound such as an alkali metal compound or an alkaline earth metal compound is used as a polymerization initiator in the polymerization step to obtain the modified conjugated diene polymer (P), if the compound (M1) has a secondary amino group, the active hydrogen of the secondary amino group becomes a reaction site with the metal compound, and the active hydrogen is replaced by a metal element, thereby efficiently producing a metal amide compound. By polymerizing a monomer in the presence of the metal amide compound thus produced, a partial structure derived from the compound (M1) can be introduced into the polymerization initiation terminal. From the viewpoint of efficiently producing a metal amide compound by mixing the compound (M1) with the metal compound, the secondary amino group of the compound (M1) preferably constitutes part of a ring skeleton, more preferably constitutes part of a nitrogen-containing aliphatic ring.

[0026] When the compound (M1) does not have a secondary amino group, the compound (M1) may contain, together with a tertiary amino group, a halogenated alkyl group having 1 to 8 carbon atoms or a monovalent cyclic group having a structure in which a halogen atom or a methyl group is bonded to an aromatic ring (hereinafter referred to as a "cyclic group R Ｃ Preferably, the compound (M1) has a halogenated alkyl group and a cyclic group R Ｃ When a metal compound is used as a polymerization initiator, the halogen atom or active hydrogen becomes a reactive site with the metal compound, and the halogen atom or active hydrogen is replaced by the metal element, thereby efficiently generating a carbon anion. By polymerizing a monomer in the presence of the carbon anion thus generated, a partial structure derived from the compound (M1) can be easily introduced into the polymerization initiation terminal. The compound (M1) contains a halogenated alkyl group having 1 to 8 carbon atoms and a cyclic group R in addition to the secondary amino group. Ｃ It may have one or both of the above.

[0027] A preferred specific example of the compound (M1) is a compound represented by the following formula (3). (In formula (3), X １ is a group represented by the following formula (4-1) or formula (4-2): １ is a hydrocarbon group having 1 to 20 carbon atoms and a valence of (i+k), or a group having one or both of nitrogen and oxygen atoms, not having active hydrogen, and containing the group "-Si(R １ ) ｎ (Y １ ) ３－ｎ " and a group represented by the following formula (4-2) via a carbon atom. R １ is a hydrocarbyl group having 1 to 20 carbon atoms. １ is the group "-OR ２ ". R ２ is a hydrocarbyl group having 1 to 20 carbon atoms. n is an integer of 0 to 2. When n is 0 or 1, a plurality of Y １ are the same or different. When n is 2, a plurality of R １ are the same or different, and i and k are each independently an integer of 1 to 6, provided that i+k≦10 is satisfied. １ If there are multiple X １ are the same or different. The group "-Si(R １ ) ｎ (Y １ ) ３－ｎ When there are a plurality of groups "-Si(R １ ) ｎ (Y １ ) ３－ｎ " are the same or different.) (In formula (4-1), R ５ R is a hydrogen atom, a halogenated alkyl group having 1 to 8 carbon atoms, or a monovalent cyclic group having a structure in which a halogen atom or a methyl group is bonded to an aromatic ring. ６ and R ７ are each independently a hydrocarbylene group having 1 to 10 carbon atoms. １ and Q ２ are each independently a nitrogen atom or —CR １０ -. However, R ５ If is a hydrogen atom, Q １is a nitrogen atom. １０ is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms. "*" represents a bond. In formula (4-2), R ８ represents a hydrogen atom, a halogenated alkyl group having 1 to 8 carbon atoms, or a monovalent cyclic group having a structure in which a halogen atom or a methyl group is bonded to an aromatic ring (cyclic group R Ｃ ) R ９ is a hydrocarbyl group or a trihydrocarbylsilyl group having 1 to 20 carbon atoms, provided that R ８ When is a hydrogen atom, R ９ is a hydrocarbyl group having 1 to 20 carbon atoms. "*" represents a bond.

[0028] In formula (3), X １ is a group represented by formula (4-1), X １ From the viewpoint of obtaining a crosslinked product having excellent rolling resistance, R preferably has a nitrogen-containing heterocycle, and more preferably has a nitrogen-containing heterocycle containing a tertiary nitrogen atom. ６ and R ７ The hydrocarbylene group having 1 to 10 carbon atoms represented by the formula (I) is preferably a linear or branched alkanediyl group having 1 to 20 carbon atoms, more preferably a methylene group or an ethylene group.

[0029] Q １ and Q ２ The group represented by -CR １０ -, then R １０ The hydrocarbyl group having 1 to 20 carbon atoms represented by the formula (I) is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms. １０ Among these, a hydrogen atom or a methyl group is preferred. From the viewpoint of improving the rolling resistance of the resulting crosslinked body, Q １ and Q ２ is preferably a nitrogen atom. １ and Q ２ Q of ２ is a tertiary nitrogen atom, or Q １ and Q ２ It is particularly preferred that both are tertiary nitrogen atoms.

[0030] R５ and R ８ Examples of halogenated alkyl groups having 1 to 8 carbon atoms represented by the formula (I) include groups in which any hydrogen atom in an alkyl group having 1 to 8 carbon atoms is substituted with a halogen atom. The alkyl group having 1 to 8 carbon atoms substituted with a halogen atom may be linear or branched. The alkyl group is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms. Examples of halogen atoms include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a chlorine atom or a bromine atom being preferred.

[0031] R ５ and R ８ The group represented by the following formula is a cyclic group R Ｃ When the cyclic group R Ｃ Examples of the aromatic ring contained in the cyclic group R include a benzene ring, a naphthalene ring, and an anthracene ring, and a benzene ring or a naphthalene ring is preferred. Ｃ In the above formula, the aromatic ring may further have a substituent other than a halogen atom and a methyl group. Examples of such a substituent include an N,N-dialkylamino group. Examples of the halogen atom bonded to the aromatic ring include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. A chlorine atom or a bromine atom is preferred, and a bromine atom is more preferred.

[0032] R ５ and R ８ The group represented by the following formula is a cyclic group R ＣSpecific examples of the above-mentioned alkyl group include a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, a 2-bromophenyl group, a 3-bromophenyl group, a 4-bromophenyl group, a 2-N,N-dimethylamino-3-methylphenyl group, a 2-N,N-dimethylamino-4-methylphenyl group, a 2-N,N-dimethylamino-5-methylphenyl group, a 2-methyl-3-N,N-dimethylaminophenyl group, a 3-N,N-dimethylamino-4-methylphenyl group, a 3- Examples include an N,N-dimethylamino-5-methylphenyl group, a 2-N,N-dimethylamino-3-bromophenyl group, a 2-N,N-dimethylamino-4-bromophenyl group, a 2-N,N-dimethylamino-5-bromophenyl group, a 2-bromo-3-N,N-dimethylaminophenyl group, a 3-N,N-dimethylamino-4-bromophenyl group, a 3-N,N-dimethylamino-5-bromophenyl group, a 5-bromonaphthalenyl group, and a 5-bromoanthracenyl group.

[0033] From the viewpoint of reactivity with metal compounds, R ５ is a hydrogen atom, a cyclic group R Ｃ Alternatively, it is preferably a halogenated alkyl group having 1 to 8 carbon atoms, and more preferably a hydrogen atom, a monovalent cyclic group having a structure in which a bromine atom is bonded to an aromatic ring, a bromoalkyl group having 1 to 8 carbon atoms, or a chloroalkyl group having 1 to 8 carbon atoms. ８ is a cyclic group R Ｃ Alternatively, it is preferably a halogenated alkyl group having 1 to 8 carbon atoms, and more preferably a monovalent cyclic group having a structure in which a bromine atom is bonded to an aromatic ring, a bromoalkyl group having 1 to 8 carbon atoms, or a chloroalkyl group having 1 to 8 carbon atoms.

[0034] R ９ The hydrocarbyl group having 1 to 20 carbon atoms represented by the formula (I) is preferably an alkyl group having 1 to 20 carbon atoms, more preferably a linear or branched alkyl group having 1 to 20 carbon atoms. Examples of the trihydrocarbylsilyl group include a trimethylsilyl group and a triethylsilyl group. X １ In order to enhance the reactivity of X with the metal compound, １ is preferably a group represented by formula (4-1).

[0035] A １ is an (i+k)-valent hydrocarbyl group, examples of which include groups in which (i+k) hydrogen atoms have been removed from a chain hydrocarbon having 1 to 20 carbon atoms, an alicyclic hydrocarbon having 3 to 20 carbon atoms, or an aromatic hydrocarbon having 6 to 20 carbon atoms. Of these, groups in which (i+k) hydrogen atoms have been removed from a chain hydrocarbon are preferred.

[0036] A １ is an (i+k)-valent group having 1 to 20 carbon atoms, containing either or both of a nitrogen atom and an oxygen atom, and containing no active hydrogen, specific examples include an (i+k)-valent heterocyclic group, an (i+k)-valent group having a tertiary amine structure, etc. The heterocyclic group is preferably a conjugated system, and examples thereof include a monocyclic or fused ring such as pyridine, pyrimidine, pyrazine, quinoline, naphthalidine, furan, etc., or a group in which (i+k) hydrogen atoms have been removed from the ring portion of a structure in which a plurality of such monocyclic or fused rings are linked together.

[0037] (i+k) is an integer of 2 to 10. From the viewpoint of processability of the polymer composition, (i+k) is preferably an integer of 2 to 6. R １ and R ２ Examples of the hydrocarbyl group having 1 to 20 carbon atoms represented by R include an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms. １ and R ２ is preferably a linear or branched alkyl group having 1 to 20 carbon atoms, and more preferably a linear or branched alkyl group having 1 to 12 carbon atoms. １ represents the group "-Si(R １ ) ｎ (Y １ ) ３－ｎ and the group represented by formula (4-2) above via a carbon atom, and more specifically, it is preferred that they are bonded via the same or different carbon atoms constituting the hydrocarbon group.

[0038] Specific examples of the compound (M1) include compounds represented by the following formulas (M1-1) to (M1-50). As the compound (M1), one type may be used alone, or two or more types may be used in combination.

[0039] (Compound (M2)) The compound (M2) is not particularly limited as long as it has one or more nitrogen atoms and one or more hydrocarbyloxysilyl groups. When a conjugated diene polymer having an active end (more specifically, a metal end) is obtained in the polymerization step for obtaining the modified conjugated diene polymer (P) and then the conjugated diene polymer having the active end is reacted with the compound (M2), the hydrocarbyloxysilyl group becomes a reaction site with the active end of the conjugated diene polymer, and a partial structure derived from the compound (M2) can be introduced into the terminal end of the polymer. The molecular weight of the compound (M2) is preferably 1,000 or less, more preferably 800 or less.

[0040] The number of reactive sites with the active terminal of the polymer in the compound (M2) may be only one or may be two or more. For example, when the number of reactive sites with the active terminal of the polymer in the compound (M2) is one, a modified conjugated diene-based polymer (P) having a partial structure derived from the compound (M2) at one terminal can be obtained as the modified conjugated diene-based polymer (P). Furthermore, when the number of reactive sites with the active terminal of the polymer in the compound (M2) is two or more, a modified conjugated diene-based polymer (P) having a structure in which each terminal of a plurality of polymer chains is bonded to a partial structure derived from the compound (M2) can be obtained as the modified conjugated diene-based polymer (P). In terms of achieving a good balance of strength, abrasion resistance, and rolling resistance, the number of reactive sites with the active terminal in the compound (M2) is preferably two or more, more preferably two to six, and even more preferably two to four.

[0041] A preferred specific example of the compound (M2) is at least one selected from the group consisting of a compound represented by the following formula (4), a compound represented by the following formula (5), and a compound represented by the following formula (6): (In formula (4), A ３ has at least one atom selected from the group consisting of nitrogen, phosphorus, oxygen, and silicon, does not have active hydrogen, and R ２２ R is a monovalent functional group bonded to R via nitrogen, phosphorus, oxygen, or silicon, or a hydrocarbyl group having 1 to 20 carbon atoms. ２２ is a single bond or a hydrocarbylene group, and R ２３ and R ２４ are each independently a hydrocarbyl group, and R ２５ is a hydrocarbylene group, and t is 0 or 1. However, when t is 0, multiple R ２４ are the same or different.) (In formula (5), R ３１ is a hydrocarbylene group having 1 to 20 carbon atoms, and R ３２ and R ３３ are each independently a hydrocarbyl group having 1 to 20 carbon atoms, and A ４ is the group "*-C(R ３５ )=N-" or the group "*-N=C(R ３５ ) -" (However, R ３５ is a hydrogen atom or a hydrocarbyl group, and * is R ３４ represents a bond bonded to the atom. ３４ is an m-valent hydrocarbon group having 1 to 20 carbon atoms, or an m-valent group having 1 to 20 carbon atoms that has one or both of a nitrogen atom and an oxygen atom and does not have active hydrogen. n is an integer of 1 to 3, and m is an integer of 2 to 10. R ３１ ~R ３３ and A １ For each symbol, when the same symbol is present multiple times in the formula, the groups represented by the symbols may be the same or different. Multiple n's in the formula may be the same or different. (In formula (6), R ４２ , R ４３ and R ４５ are each independently an alkanediyl group having 1 to 12 carbon atoms, and R ４０, R ４１ , R ４８ and R ４９ are each independently a hydrocarbyl group having 1 to 20 carbon atoms. ２ represents a nitrogen-containing heterocyclic group or the following formula (a-2): (In formula (a-2), R ４６ and R ４７ are each independently a hydrocarbyl group having 1 to 20 carbon atoms. a is an integer of 1 to 3. When the same symbol exists multiple times in the formula, the groups represented by those symbols are the same or different from each other. "*" represents a bond.) is a group represented by. c and d are each independently an integer of 1 to 3, and b is an integer of 1 to 10. When the same symbol exists multiple times in the formula, the groups represented by those symbols are the same or different from each other.)

[0042] In the above formula (4), R ２３ , R ２４ The hydrocarbyl group represented by R 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. ２２ 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. ２５ is preferably a linear or branched alkanediyl group having 1 to 20 carbon atoms.

[0043] A ３ At least one atom selected from the group consisting of nitrogen, phosphorus, oxygen, and silicon contained in A is not bonded to an active hydrogen and may be protected by a protecting group (for example, a tri-substituted hydrocarbylsilyl group). ３ may be a group that can be converted into an onium ion by an onium salt generating agent.

[0044] A ３Specific examples of A include a nitrogen-containing group in which two hydrogen atoms of a primary amino group are substituted with two protecting groups, a nitrogen-containing group in which one hydrogen atom of a secondary amino group is substituted with one protecting group, 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 substituted with two protecting groups, a phosphorus-containing group in which one hydrogen atom of a secondary phosphino group is substituted with one protecting group, a tertiary phosphino group, a group in which the hydrogen atom of a hydroxyl group is protected with a protecting group, a hydrocarbyloxysilyl group, etc. ３ is preferably a group having silicon or nitrogen, and more preferably a hydrocarbyloxysilyl group, a nitrogen-containing group having a protecting group, or a tertiary amino group. Examples of the hydrocarbyloxysilyl group include a trimethoxysilyl group, a methyldimethoxysilyl group, a dimethylmethoxysilyl group, and groups in which the methyl group in these groups is replaced with an alkyl group or alkenyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

[0045] In the above formula (5), R ３１ Examples of the hydrocarbylene group include an alkanediyl group having 1 to 12 carbon atoms, a cycloalkylene group having 3 to 12 carbon atoms, and an arylene group having 6 to 12 carbon atoms. ３２ and R ３３ Examples of the hydrocarbyl group include an alkyl group having 1 to 20 carbon atoms, an allyl group, a cycloalkyl group having 3 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms.

[0046] R ３４ The m-valent hydrocarbon group is a group obtained by removing m hydrogen atoms from a hydrocarbon. ３４ The m-valent hydrocarbon group is preferably a group (m-valent aromatic ring group) obtained by removing m hydrogen atoms from the ring portion of an aromatic hydrocarbon. Specific examples of aromatic hydrocarbons include single rings or condensed rings such as benzene rings, naphthalene rings, and anthracene rings, and structures in which two or more of these rings are bonded by a single bond.

[0047] R ３４is an m-valent group having 1 to 20 carbon atoms, containing one or both of a nitrogen atom and an oxygen atom, and containing no active hydrogen, specific examples thereof include an m-valent heterocyclic group, an m-valent group having a tertiary amine structure, etc. The heterocyclic group is preferably a conjugated system, and examples thereof include a single ring or condensed ring such as pyridine, pyrimidine, pyrazine, quinoline, naphthalidine, furan, etc., or a group in which m hydrogen atoms have been removed from the ring portion of a structure in which a plurality of these rings are linked together.

[0048] From the viewpoint of improving the processability of the polymer composition, m is preferably 2 to 6. n is preferably 2 or 3, and more preferably 3, from the viewpoint of enhancing the effect of improving silica dispersibility.

[0049] In the above formula (6) and formula (a-2), R ４５ , R ４２ and R ４３ The alkanediyl group in R is preferably linear. ４０ , R ４１ , R ４６ ~R ４９ Examples of the hydrocarbyl group include an alkyl group having 1 to 20 carbon atoms, an allyl group, a cycloalkyl group having 3 to 20 carbon atoms, and an aryl group having 6 to 20 carbon atoms. ２ The nitrogen-containing heterocyclic group represented by the formula (I) is preferably a group derived from a conjugated heterocycle, and examples thereof include groups in which one hydrogen atom has been removed from a nitrogen-containing heterocycle such as pyrrole, imidazole, pyridine, pyrimidine, pyrazine, quinoline, naphthalidine, or benzimidazole.

[0050] a, c, and d are preferably 2 or 3, more preferably 3, in that they have a high effect of improving the dispersibility of the filler (particularly silica). b is preferably 1 to 5, more preferably 1 to 3.

[0051] Specific examples of compound (M2) include compounds represented by the above formula (4), such as 1-trimethylsilyl-2,2-dimethoxy-1-aza-2-silacyclopentane, 1-triethylsilyl-2,2-diethoxy-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1,2-azasilolidine, 2,2-dimethoxy-1-phenyl-1,2-azasilolidine, 2-(2,2-dimethoxy-1,2-azasilolidine-1-yl)-N,N-diethylethan-1-amine, and compounds in which the alkyl groups and alkanediyl groups in these compounds are replaced with alkyl groups having 1 to 6 carbon atoms and alkanediyl groups having 1 to 6 carbon atoms, respectively.

[0052] Examples of the compound represented by formula (5) include compounds represented by the following formulae (M2-1-1) to (M2-1-7): and compounds in which the alkyl group and alkanediyl group in the compounds are replaced with an alkyl group having 1 to 6 carbon atoms and an alkanediyl group having 1 to 6 carbon atoms, respectively.

[0053] Examples of the compound represented by the formula (6) include tris(2-triethoxysilylethyl)amine, tris(3-triethoxysilylpropyl)amine, tris(5-triethoxysilylpentyl)amine, N,N,N',N'-tetra(2-triethoxysilylethyl)-1,2-diaminoethane, N,N,N',N'-tetra(3-triethoxysilylpropyl)-1,3-diaminopropane, N-(3-(1H-imidazole-1- N-(3-(1H-imidazol-1-yl)propyl)-3-(trimethoxysilyl)-N-(3-(trimethoxysilyl))propyl)propan-1-amine, N-(3-(1H-imidazol-1-yl)propyl)-N,N-bis(3-(trimethoxysilyl))propyl)propanamine, and compounds in which the alkyl group and alkanediyl group in these compounds are replaced with an alkyl group having 1 to 6 carbon atoms and an alkanediyl group having 1 to 6 carbon atoms, respectively. As the terminal modifying agent, one type may be used alone, or two or more types may be used in combination.

[0054] In order to improve the rolling resistance and strength in a well-balanced manner in the crosslinked body obtained using the modified conjugated diene polymer (P), the modified conjugated diene polymer (P) preferably has a partial structure derived from the compound (M2). When the modified conjugated diene polymer (P) has a partial structure derived from the compound (M2), the modified conjugated diene polymer (P) may further have a partial structure derived from the compound (M1) in addition to the partial structure derived from the compound (M2). Furthermore, using at least a compound having two or more hydrocarbyloxysilyl groups as the compound (M) is preferable in that it allows to obtain a crosslinked body having improved rolling resistance, strength, and abrasion resistance in a well-balanced manner.

[0055] <Physical Properties of Modified Conjugated Diene Polymer (P)> Next, the physical properties of the modified conjugated diene polymer (P) will be described.

[0056] (Mooney Viscosity) The modified conjugated diene polymer (P) has a Mooney viscosity measured at 160°C of 80 or more and 150 or less. If the Mooney viscosity of the modified conjugated diene polymer measured at 160°C is less than 80, the strength, abrasion resistance, and rolling resistance of a crosslinked body obtained using the modified conjugated diene polymer tend not to be improved in a balanced manner. If the Mooney viscosity of the modified conjugated diene polymer measured at 160°C is higher than 150, the processability of the modified conjugated diene polymer is poor. From the above viewpoints, the Mooney viscosity of the modified conjugated diene polymer (P) measured at 160°C is preferably 90 or more, more preferably 95 or more, and even more preferably 100 or more. If the Mooney viscosity of the modified conjugated diene polymer measured at 160°C is 140 or less, the Mooney viscosity is preferably 140 or less.

[0057] The Mooney viscosity of the modified conjugated diene polymer (P) at 160°C is a value measured under the conditions described in JIS K6300-1, except that the measurement temperature is 160°C. The Mooney viscosity of the modified conjugated diene polymer (P) can be adjusted to fall within the above range by controlling the weight average molecular weight and molecular weight distribution (= weight average molecular weight / number average molecular weight) of the modified conjugated diene polymer (P), the presence or absence of branches and the number of branches, the molar ratio of the terminal modifier to the polymerization initiator, the polymerization temperature, etc. The Mooney viscosity of the modified conjugated diene polymer (P) may also be adjusted to fall within the above range by the amount of extender oil added.

[0058] (Vinyl Group Content) The vinyl group content of the modified conjugated diene polymer (P) is preferably 10 to 70% by mass. A vinyl group content of 10% by mass or more is preferable in that it can improve grip properties, and a vinyl group content of 70% by mass or less is preferable in that it can suppress a decrease in the abrasion resistance of the resulting vulcanized rubber. The vinyl group content is more preferably 12% by mass or more, and even more preferably 15% by mass or more. The vinyl group content is more preferably 60% by mass or less, even more preferably 50% by mass or less, even more preferably 45% by mass or less, and particularly preferably 30% by mass or less. In this specification, the "vinyl group content" is a value indicating the content ratio of structural units having 1,2-bonds to all structural units of butadiene in the conjugated diene polymer, １ This is a value measured by H-NMR.

[0059] (Content of structural units derived from aromatic vinyl compounds) In the modified conjugated diene polymer (P), the content of structural units derived from aromatic vinyl compounds is preferably 3 to 55 mass% relative to the total amount of structural units possessed by the modified conjugated diene polymer (P), from the viewpoint of achieving a good balance between the rolling resistance and wet skid resistance of the resulting crosslinked body. The content of structural units derived from aromatic vinyl compounds is more preferably 5 mass% or more, and even more preferably 10 mass% or more. The content of structural units derived from aromatic vinyl compounds is more preferably 45 mass% or less, even more preferably 40 mass% or less, even more preferably 35 mass% or less, and even more preferably 30 mass% or less. The content of structural units derived from aromatic vinyl compounds in the conjugated diene polymer is １ This is a value measured by H-NMR.

[0060] (Weight-average molecular weight) The weight-average molecular weight (Mw) of the modified conjugated diene polymer (P) measured by gel permeation chromatography (GPC) in terms of polystyrene was 7.0 × 10 ５ Above 3.0 x 10 ６ The Mw of the modified conjugated diene polymer (P) is preferably 7.0 × 10 or less. ５ When the Mw of the modified conjugated diene polymer (P) is 3.0×10 or more, a crosslinked product having higher strength, excellent wear resistance, and sufficiently low rolling resistance can be obtained. ６ When the Mw of the modified conjugated diene polymer (P) is 7.2 × 10 or less, the processability of the polymer composition containing the modified conjugated diene polymer (P) can be improved. From the viewpoint of further enhancing the effects of improving strength, abrasion resistance, and rolling resistance, the Mw of the modified conjugated diene polymer (P) is more preferably 7.2 × 10 or less. ５ More preferably, it is 7.5×10 ５ From the viewpoint of processability, the Mw of the modified conjugated diene polymer (P) is more preferably 2.5 × 10 ６ More preferably, it is 2.0 × 10 ６ The weight average molecular weight (Mw) of the modified conjugated diene polymer represents the weight average molecular weight (total weight average molecular weight) based on all peaks of a GPC curve measured by GPC.

[0061] (Molecular Weight Distribution) The molecular weight distribution (Mw / Mn) of the modified conjugated diene polymer (P), measured using GPC and expressed as the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), is preferably 1.60 or more and 4.00 or less from the viewpoint of productivity, etc. The molecular weight distribution (Mw / Mn) of the modified conjugated diene polymer (P) is more preferably 3.00 or less, and even more preferably 2.50 or less. Furthermore, the molecular weight distribution (Mw / Mn) of the modified conjugated diene polymer (P) is more preferably 1.70 or more, and even more preferably 1.80 or more.

[0062] (Glass Transition Temperature) The modified conjugated diene polymer (P) preferably has an endothermic peak in the temperature range of -100°C to 20°C in differential scanning calorimetry (DSC) in accordance with JIS K6240:2011. The inflection point of the DSC curve obtained by DSC analysis, i.e., the peak top temperature of the differential curve, is the measured value of the glass transition temperature of the modified conjugated diene polymer (P). In other words, the modified conjugated diene polymer (P) preferably has a glass transition temperature of -100°C to 20°C.

[0063] The glass transition temperature of the modified conjugated diene polymer (P) is more preferably −90° C. or higher, and even more preferably −80° C. or higher. From the viewpoint of improving wet grip performance, the glass transition temperature of the modified conjugated diene polymer (P) is more preferably −20° C. or lower, even more preferably −40° C. or lower, even more preferably −50° C. or lower, and particularly preferably −55° C. or lower. In particular, when the modified conjugated diene polymer (P) has only one endothermic peak in DSC analysis and the peak temperature of the endothermic peak is in the temperature range of −100° C. to 20° C., the abrasion resistance and strength of the crosslinked body formed using the modified conjugated diene polymer (P) tend to be good.

[0064] <<Method for Producing Modified Conjugated Diene Polymer>> The method for producing the modified conjugated diene polymer (P) is not particularly limited. The modified conjugated diene polymer (P) is preferably produced by a method including the following polymerization step and modification step. Polymerization step: A step of polymerizing a monomer containing a conjugated diene compound in the presence of a polymerization initiator to obtain a conjugated diene polymer having an active end. Modification step: A step of reacting a conjugated diene polymer having an active end with a compound (M). Each step will be described in detail below.

[0065] <Polymerization Step> In the polymerization step, a solution polymerization method is particularly preferred as the polymerization method for polymerizing a monomer containing a conjugated diene compound. The polymerization method may be either a batch method or a continuous method. When using a solution polymerization method, a specific example of the polymerization method is a method in which a monomer is polymerized in an organic solvent in the presence of a polymerization initiator and, if necessary, a vinyl group content adjuster (randomizer). From the viewpoints of improving the processability of the polymer composition, increasing the dispersibility of the filler (particularly silica), obtaining a high-strength crosslinked body, and polymer productivity, a continuous method (specifically, a method in which raw materials are continuously fed into a reactor and a product is continuously withdrawn from the reactor) is preferred.

[0066] In a continuous polymerization system, the raw material supply rate may be constant or variable. Furthermore, as long as the polymerization reaction includes a step of continuously supplying raw materials to a reactor, the polymerization reaction may further include a step of intermittently supplying raw materials. Similarly, in a continuous polymerization system, the product withdrawal rate may be constant or variable. Furthermore, as long as the polymerization reaction includes a step of continuously withdrawing the product from the reactor, the polymerization reaction may further include a step of intermittently withdrawing the product.

[0067] As the polymerization initiator, an alkali metal compound or an alkaline earth metal compound can be preferably used, and an alkali metal compound is more preferred. Specific examples of the polymerization initiator include alkyllithium, 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, di-n-butylmagnesium, di-n-hexylmagnesium, ethoxypotassium, and calcium stearate. Specific examples of the alkyllithium include methyllithium, ethyllithium, n-propyllithium, n-butyllithium, sec-butyllithium, and t-butyllithium. The polymerization initiator is preferably a lithium compound. The proportion of polymerization initiator used during polymerization (the total amount when two or more types are used) is preferably 0.2 to 20 mmol per 100 g of monomer used in polymerization.

[0068] The polymerization reaction may be carried out in the presence of a metal amide compound obtained by mixing an alkali metal compound or alkaline earth metal compound with an initiation terminal-modifying agent. By polymerizing a monomer in the presence of the metal amide compound, a functional group derived from the initiation terminal-modifying agent can be introduced into the polymerization initiation terminal of the conjugated diene polymer.

[0069] As the initiating end modifying agent, nitrogen-containing compounds such as secondary amine compounds can be preferably used. Specific examples of the initiating end modifying agent include, in addition to the above-mentioned compound (M1), chain amines such as dimethylamine, diethylamine, dipropylamine, dibutylamine, dodecamethyleneimine, N,N'-dimethyl-N'-trimethylsilyl-1,6-diaminohexane, di-(2-ethylhexyl)amine, and diallylamine; and cyclic amines such as piperidine, pyrrolidine, hexamethyleneimine, heptamethyleneimine, dicyclohexylamine, N-methylbenzylamine, morpholine, N-(trimethylsilyl)piperazine, N-(tert-butyldimethylsilyl)piperazine, and 1,3-ditrimethylsilyl-1,3,5-triazinane.

[0070] When polymerizing a monomer in the presence of a compound obtained by mixing an alkali metal compound or alkaline earth metal compound with an initiating terminal modifier, at least one of the alkali metal compound and alkaline earth metal compound and the initiating terminal modifier may be mixed in advance, and the mixture may be added to the polymerization system to carry out polymerization. Alternatively, at least one of the alkali metal compound and alkaline earth metal compound and the initiating terminal modifier may be added to the polymerization system separately or simultaneously, and the two may be mixed in the polymerization system to carry out polymerization. Either of these cases is included in the embodiment of "polymerizing a monomer in the presence of a compound obtained by mixing an alkali metal compound or alkaline earth metal compound with an initiating terminal modifier."

[0071] The amount of initiating end-modifier used is appropriately set depending on the type of alkali metal compound or alkaline earth metal compound. For example, when a lithium compound is used as the alkali metal compound or alkaline earth metal compound, from the viewpoint of obtaining a modified conjugated diene-based polymer (P) with a well-balanced improvement in processability and rolling resistance, the amount of initiating end-modifier used is preferably in the range of 0.1 to 1.8 mol, more preferably in the range of 0.2 to 1.0 mol, per mol of the total lithium metal used in the polymerization. One initiating end-modifier can be used alone, or two or more can be used in combination.

[0072] The vinyl group content adjuster (randomizer) is used for the purpose of adjusting the vinyl group content, which represents the content of vinyl bonds in the modified conjugated diene polymer. Examples of randomizers include dimethoxybenzene, tetrahydrofuran, dimethoxyethane, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, 2,2-di(tetrahydrofuryl)propane, 2-(2-ethoxyethoxy)-2-methylpropane, triethylamine, pyridine, N-methylmorpholine, and tetramethylethylenediamine. One type of randomizer can be used alone, or two or more types can be used in combination.

[0073] The organic solvent used in the polymerization may be any organic solvent that is inert to the reaction. Examples of such organic solvents include linear or cyclic aliphatic hydrocarbons and aromatic hydrocarbons. The organic solvent used in the polymerization is preferably a hydrocarbon having 3 to 8 carbon atoms, 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, and cyclohexene. These organic solvents may be used alone or in combination of two or more.

[0074] 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. Furthermore, when polymerization is performed using a continuous polymerization method, the feed rate of each component, such as the monomer, is not particularly limited and can be appropriately set depending on the amount of each component added, the size of the reactor, and the like. The temperature of the polymerization reaction is preferably −20° C. to 150° C., more preferably 0 to 120° C. Furthermore, the polymerization reaction is preferably performed under a pressure sufficient to maintain the monomer substantially in a liquid phase.

[0075] Such a polymerization reaction can produce a conjugated diene polymer having an active end (more specifically, an alkali metal active end or an alkaline earth metal active end). In this specification, the term "active end" refers to a portion (more specifically, a metal end) present at the end of the molecular chain other than the structure derived from a monomer having a carbon-carbon double bond.

[0076] <Modification Step> In the modification step, it is preferable to use a compound (M2) as a terminal-modifying agent and react the active terminal of the conjugated diene polymer obtained in the polymerization step with the compound (M2). By reacting the conjugated diene polymer having an active terminal with the compound (M2), a polymer chain containing a monomer unit derived from the conjugated diene compound is bonded to the compound (M2) at a reactive site possessed by the compound (M2), thereby obtaining a modified conjugated diene polymer (P) having one or more polymer chains per molecule. This allows the crosslinked body obtained using this composition to have excellent rolling resistance. The conjugated diene polymer having an active terminal that is reacted with the terminal-modifying agent may have a modified or unmodified polymerization initiation terminal.

[0077] The reaction between the polymerization active terminal and the terminal modifier is preferably carried out as a solution reaction. This solution reaction may be carried out using a solution containing unreacted monomers after the polymerization reaction is completed, or may be carried out after isolating the conjugated diene polymer having polymerization active terminals contained in the solution and dissolving it in a suitable solvent such as cyclohexane. The reaction may be carried out either batchwise or continuously. From the viewpoint of productivity, it is preferable to carry out the polymerization step and the modification step in series in a continuous manner.

[0078] The amount of the terminal modifier used in the above reaction may be appropriately set depending on the type of compound used in the reaction. The amount of the terminal modifier used is preferably 0.1 mol equivalent or more, more preferably 0.3 mol equivalent or more, relative to the metal atoms of the polymerization initiator involved in the polymerization reaction. By using an amount of the terminal modifier used in the above reaction of 0.1 mol equivalent or more, the modification reaction can be sufficiently progressed and the dispersibility of the filler can be suitably improved. In addition, the amount of the terminal modifier used is preferably 1.5 mol equivalent or less, more preferably 1.2 mol equivalent or less, relative to the metal atoms of the polymerization initiator involved in the polymerization reaction.

[0079] The reaction temperature is usually the same as the polymerization reaction temperature, and is preferably -20°C to 150°C, and more preferably 0 to 120°C. If the reaction temperature is too low, the viscosity of the modified conjugated diene polymer (P) tends to increase. On the other hand, if the reaction temperature is too high, the polymerization active terminals tend to be deactivated. The reaction time is preferably 1 minute to 5 hours, and more preferably 2 minutes to 1 hour.

[0080] When a compound having a protecting group (e.g., a trimethylsilyl group) is used as a terminal-modifying agent in producing the modified conjugated diene polymer (P), a modified conjugated diene polymer having a protecting group derived from the terminal-modifying agent can be obtained. The modified conjugated diene polymer having a protecting group derived from the terminal-modifying agent may be used in a subsequent step as the modified conjugated diene polymer (P) after some or all of the protecting groups have been substituted with hydrogen. Furthermore, when a protecting-group-containing compound is used as the terminal-modifying agent, the modified conjugated diene polymer modified with the terminal-modifying agent may be further reacted with an onium salt generating agent. In this case, a polymer having an onium salt structure at the polymer terminal can be obtained as the modified conjugated diene polymer (P). The onium salt structure in the modified conjugated diene polymer (P) can improve the shape retention of a crosslinked product obtained using the polymer composition. The onium salt generating agent is a Brønsted acid or a compound that generates a Brønsted acid upon contact with water.

[0081] As a specific method for obtaining the modified conjugated diene polymer (P), it is preferable to carry out polymerization of a monomer in a solvent in the presence of a polymerization initiator in a continuous polymerization mode in the polymerization step, and then to obtain a polymer solution by reacting a polymer having an active end with a compound (M) in the subsequent modification step. The polymer contained in the polymer solution can be isolated by a known desolvation method or a drying operation such as heat treatment.

[0082] When removing the solvent from the polymer solution obtained by reacting the polymer having an active end with the compound (M), it is preferable to carry out the following solvent removal step: solvent removal step: a step of removing the solvent from the polymer solution obtained by the modification step without adding an extender oil to the polymer solution.

[0083] <Solvent Removal Step> In the solvent removal step, the solvent is removed from the polymer solution obtained by reacting a polymer having an active end with the compound (M) (i.e., the polymer solution obtained by the modification step) without adding an extender oil. This isolates the modified conjugated diene-based polymer (P). The method for removing the solvent from the polymer solution is not particularly limited, and can be performed by known solvent removal methods such as, for example, a method in which the polymer solution is contacted with water to remove the solvent (steam stripping), and the resulting polymer is dehydrated and dried; a method of devolatilization using a twin-screw extruder or the like; or a method of direct devolatilization using a drum dryer or the like. Among these, the method including steam stripping and dehydration / drying is preferred because it allows for easy solvent removal.

[0084] According to the production method including the above-mentioned polymerization step, modification step, and desolvation step, a solid modified conjugated diene polymer (P) from which the solvent has been removed can be obtained. One embodiment of the obtained modified conjugated diene polymer (P) is solid particles (crumbs), and another embodiment is a rubber bale obtained by compression molding the crumbs into a predetermined shape (e.g., a rectangular parallelepiped shape). The modified conjugated diene polymer (P) after desolvation does not contain extender oil. Furthermore, according to the present disclosure, a rubber bale containing the modified conjugated diene polymer (P) but not containing extender oil can be obtained.

[0085] The phrase "the modified conjugated diene polymer (P) after solvent removal does not contain extender oil" means that the amount of extender oil in the modified conjugated diene polymer (P) is, for example, 0.5 parts by mass or less, preferably 0.1 parts by mass or less, and more preferably 0.01 parts by mass or less, per 100 parts by mass of the modified conjugated diene polymer (P). The phrase "a rubber bale free of extender oil" means that the amount of extender oil in the rubber bale is, for example, 0.5 parts by mass or less, preferably 0.1 parts by mass or less, and more preferably 0.01 parts by mass or less, per 100 parts by mass of the rubber bale. The use of such a modified conjugated diene polymer (P) (preferably a rubber bale of the modified conjugated diene polymer (P)) makes it possible to obtain a crosslinked product that has high strength and excellent abrasion resistance and rolling resistance. Furthermore, it is also possible to obtain a rubber bale that has excellent contamination resistance.

[0086] After the solvent removal and drying treatment, the water content of the modified conjugated diene polymer (P) is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, and even more preferably 0.5% by mass or less. The Mooney viscosity of the modified conjugated diene polymer (P) measured at 160°C is a value measured using the modified conjugated diene polymer (P) after the solvent removal and drying treatment.

[0087] <Polymer Composition> The polymer composition of the present disclosure contains the modified conjugated diene polymer (P) and at least one filler (hereinafter also simply referred to as "filler") selected from the group consisting of silica, carbon black, and a compound represented by the following formula (1): １ mSiO ｋ ・iH ２ O...(1) (In formula (1), M １ is at least one selected from the group consisting of any one of aluminum, magnesium, titanium, zirconium, and calcium (hereinafter also referred to as "specific metal"), oxides of specific metals, hydroxides of specific metals, and carbonates of specific metals. n is an integer of 1 to 5, m is an integer of 0 to 10, k is an integer of 2 to 5, and i is an integer of 0 to 10.

[0088] <Filler> [B] Silica The polymer composition of the present disclosure may contain silica as a filler. The amount of silica is preferably 20 to 160 parts by mass, more preferably 30 to 150 parts by mass, per 100 parts by mass of the rubber component containing the modified conjugated diene polymer (P). When the amount of silica is 20 parts by mass or more per 100 parts by mass of the rubber component, the rolling resistance, fracture properties, and abrasion resistance of the crosslinked body obtained from the polymer composition can be sufficiently improved. Furthermore, when the amount of silica is 160 parts by mass or less, the processability of the polymer composition can be sufficiently improved.

[0089] In this specification, the "rubber component" contained in the polymer composition refers to a polymer that can be cured to give a cured product exhibiting rubber elasticity. The cured product exhibits the property of undergoing large deformation under small force at room temperature (for example, stretching 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.

[0090] The silica is not particularly limited, and examples thereof include wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate, and rice husk silica. Among these, wet silica is preferred. Silica may be used alone or in combination of two or more types. The BET specific surface area of ​​the silica (measured in accordance with ISO 5794 / 1) is 40 to 350 m. ２ / g, and 80 to 300m ２ / g is more preferably in the range of 120 to 250m ２ / g is particularly preferred. Silica having a BET specific surface area in this range has the advantage of being able to achieve both dispersibility in modified conjugated diene polymers and rubber reinforcement properties. Examples of such silica include "Nipsil AQ" (BET specific surface area = 205 m), manufactured by Tosoh Silica Corporation. ２ / g), "Nipsil KQ", product name "Ultrasil VN3" (BET specific surface area = 175 m), manufactured by Degussa ２ Commercially available products such as PEG-100 / g can be used.

[0091] The silica contained in the polymer composition may be a mixture of two or more types having different specific surface areas. Specifically, CTAB (cetyltrimethylammonium bromide) having a specific surface area of ​​180 m ２ / g or more, BET specific surface area is 185m ２ / g or more, and an aggregate size of 45 nm or more; and a CTAB specific surface area of ​​95 m ２ / g or less, BET specific surface area is 100m ２ / g or less. The CTAB specific surface area of ​​silica is measured in accordance with ASTM D3765-92. By using such a first silica and a second silica in combination, it becomes possible to satisfactorily disperse the first silica, which has a small average primary particle size but a relatively large aggregate size, in the rubber component. This improves the dispersibility of the silica, and enables the achievement of excellent rubber breaking strength, abrasion resistance, fuel economy, and processability.

[0092] The CTAB specific surface area of ​​the first silica is preferably 190 m ２ / g or more, more preferably 195m ２ / g or more, more preferably 197m ２ / g or more. CTAB specific surface area is 180 m ２ When the CTAB specific surface area is 350 m / g or more, the rubber breaking strength and abrasion resistance tend to be sufficiently improved. ２ / g or less, more preferably 300m ２ / g or less, more preferably 250m ２ / g or less. CTAB specific surface area is 350 m ２ When the molecular weight is 1 / g or less, the dispersibility is good and aggregation is unlikely to occur, so that deterioration of physical properties tends to be suppressed.

[0093] The BET specific surface area of ​​the first silica is preferably 190 m ２ / g or more, more preferably 195m ２ / g or more, more preferably 210m ２ / g or more. BET specific surface area is 185 m ２ When the BET specific surface area is 350 m / g or more, the rubber breaking strength and abrasion resistance tend to be sufficiently improved. ２ / g or less, more preferably 300m ２ / g or less, more preferably 260m ２ / g or less. BET specific surface area is 350 m ２ When the BET specific surface area of ​​silica is 1 / g or less, the silica has good dispersibility and is less likely to aggregate, which tends to prevent deterioration of physical properties. The BET specific surface area of ​​silica is measured in accordance with ASTM D3037-81.

[0094] The aggregate size of the first silica is 45 nm or more, preferably 50 nm or more, more preferably 55 nm or more, and even more preferably 60 nm or more. The aggregate size is preferably 100 nm or less, more preferably 80 nm or less, even more preferably 70 nm or less, and particularly preferably 67 nm or less. By having such an aggregate size, excellent fuel economy and abrasion resistance can be achieved while maintaining good dispersibility (processability). The aggregate size of silica can be measured by the method described in JP 2011-140613 A.

[0095] The average primary particle diameter of the first silica is preferably 25 nm or less, more preferably 22 nm or less, even more preferably 17 nm or less, and particularly preferably 14 nm or less. The lower limit of the average primary particle diameter is not particularly limited, but is preferably 3 nm or more, more preferably 5 nm or more, and even more preferably 7 nm or more. Although it has such a small average primary particle diameter, the carbon black-like structure having the above aggregate size can further improve the dispersibility (processability) of the silica, thereby further improving fuel economy and wear resistance. The average primary particle diameter of the silica can be determined by observing the silica with a transmission or scanning electron microscope, measuring the particle diameters of 400 or more primary silica particles observed in the field of view, and averaging the measured values.

[0096] The CTAB specific surface area of ​​the second silica is preferably 10 m ２ / g or more, more preferably 20m ２ / g or more, more preferably 30m ２ / g or more. ２When the CTAB specific surface area is 80 m / g or more, the effect of improving the reinforcing property is high, and it tends to be easy to ensure the mechanical strength and abrasion resistance required for a polymer composition for obtaining rubber for tires. ２ / g or less, more preferably 60m ２ / g or less, more preferably 50m ２ / g or less. CTAB specific surface area is 95 m ２ When the silica content is 1 / g or less, the dispersibility of silica can be ensured, and the rubber breaking strength and abrasion resistance tend to be easily improved.

[0097] The BET specific surface area of ​​the second silica is preferably 10 m ２ / g or more, more preferably 20m ２ / g or more, more preferably 30m ２ / g or more. BET specific surface area is 10 m ２ When the BET specific surface area is 85 m / g or more, the effect of improving the reinforcing property is high, and it tends to be easy to ensure the mechanical strength and abrasion resistance required for a polymer composition for obtaining rubber for tires. ２ / g or less, more preferably 60m ２ / g or less, more preferably 50m ２ / g or less. BET specific surface area is 100 m ２ When the silica content is 1 / g or less, the dispersibility of silica can be ensured, and the rubber breaking strength and abrasion resistance tend to be easily improved.

[0098] The average primary particle size of the second silica is preferably 20 nm or more, more preferably 25 nm or more, even more preferably 30 nm or more, particularly preferably 35 nm or more, and most preferably 55 nm or more. The average primary particle size is preferably 500 nm or less, more preferably 200 nm or less, even more preferably 100 nm or less, particularly preferably 70 nm or less. By having such an average primary particle size, the effect of improving rubber breaking strength and abrasion resistance can be enhanced.

[0099] [C] Carbon Black The polymer composition of the present disclosure preferably contains carbon black as a filler from the viewpoint of the fracture properties and abrasion resistance of the crosslinked body obtained from 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 (N ２ SA) is not particularly limited, but is preferably 50 to 200 m because it is superior in terms of the effects of the present disclosure. ２ / g is preferred, and 70 to 150m ２ / g is more preferred. ２ SA is the amount of nitrogen adsorption on 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." These carbon blacks may be used alone or in combination of two or more. The amount of carbon black mixed is preferably in the range of 1 to 150 parts by mass, more preferably 3 to 120 parts by mass, per 100 parts by mass of the rubber component containing the modified conjugated diene polymer (P).

[0100] [D] Compound represented by formula (1) Specific examples of the compound represented by formula (1) (hereinafter also referred to as "inorganic compound (D)") include alumina (Al), such as γ-alumina and α-alumina. ２ O ３ alumina monohydrate (Al), boehmite, diaspore, etc. ２ O ３ ・H ２ O), aluminum hydroxides such as gibbsite and bayerite [Al(OH) ３ ], aluminum carbonate [Al ２ (CO ３ ) ３ ], magnesium hydroxide [Mg(OH) ２ ], magnesium oxide (MgO), magnesium carbonate (MgCO ３ ), talc (3MgO.4SiO ２ ・H ２ O), attapulgite (5MgO.8SiO ２ ・9H ２ O), titanium white (TiO ２ ), titanium black (TiO２ｎ－１ ), calcium oxide (CaO), calcium hydroxide [Ca(OH) ２ ], magnesium aluminum oxide (MgO.Al ２ O ３ ), clay (Al ２ O ３ 2SiO ２ ), kaolin (Al ２ O ３ 2SiO ２ ・2H ２ O), pyrophyllite (Al ２ O ３ 4SiO ２ ・H ２ O), bentonite (Al ２ O ３ 4SiO ２ ・2H ２ O), aluminum silicate (Al ２ SiO ５ , Al ４ 3SiO ４ ・5H ２ O, etc.), magnesium silicate (Mg ２ SiO ４ , MgSiO ３ etc.), calcium silicate (Ca ２ SiO ４ etc.), calcium aluminum silicate (Al ２ O ３ CaO 2SiO ２ etc.), magnesium calcium silicate (CaMgSiO ４ ), calcium carbonate (CaCO ３ ), zirconium oxide (ZrO ２ ), zirconium hydroxide [ZrO(OH) ２ ・nH ２ O], zirconium carbonate [Zr(CO ３ ) ２ ] etc.

[0101] In the polymer composition of the present disclosure, the blending amount of the filler is preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and even more preferably 60 parts by mass or more, per 100 parts by mass of the rubber component. Furthermore, the blending amount of the filler is preferably 200 parts by mass or less, more preferably 160 parts by mass or less, and even more preferably 120 parts by mass or less. When the blending amount of the filler in the polymer composition is within the above range, application of the polymer composition to a tire tread can achieve an even higher level of compatibility between the tire's rolling resistance, braking performance on wet road surfaces, handling performance on dry road surfaces, and abrasion resistance.

[0102] The polymer composition of the present disclosure may further contain various components shown below in addition to the modified conjugated diene polymer (P) and the filler.

[0103] [E] Other Rubber Components The polymer composition of the present disclosure preferably further contains, as a rubber component other than the modified conjugated diene polymer (P), at least one selected from the group consisting of natural rubber, isoprene rubber, butadiene rubber, emulsion-polymerized styrene-butadiene rubber, solution-polymerized styrene-butadiene rubber, hydrogenated styrene-butadiene rubber, butyl rubber, halogenated butyl rubber, ethylene-propylene rubber, and ethylene-butadiene rubber. Among these, it is preferable to contain at least one of natural rubber, butadiene rubber, and styrene-butadiene rubber. When mixing other rubber components with the modified conjugated diene polymer (P), they are mixed during the usual kneading process using a Banbury mixer, roll, or the like.

[0104] The ratio of the modified conjugated diene polymer (P) to the other rubber components is preferably 5 to 95 parts by mass of the modified conjugated diene polymer (P) and 5 to 95 parts by mass of the other rubber components, and more preferably 20 to 90 parts by mass of the modified conjugated diene polymer (P) and 10 to 80 parts by mass of the other rubber components, relative to 100 parts by mass of the total of the modified conjugated diene polymer (P) and the other rubber components. In particular, a ratio of 35 to 85 parts by mass of the modified conjugated diene polymer (P) and 15 to 65 parts by mass of the other rubber components is suitable as a polymer composition for producing rubber for tires.

[0105] When producing the polymer composition of the present disclosure, a liquid rubber may be used as part or all of the other rubber components from the viewpoint of further improving dry grip performance, wet grip performance, and blowout resistance.

[0106] Examples of liquid rubber include liquid polyisoprene (liquid IR), liquid polybutadiene (liquid BR), liquid styrene-butadiene copolymer (liquid SBR), and liquid ethylene-propylene copolymer (liquid EP). For example, liquid SBR having a weight-average molecular weight of 1,000 to 100,000, preferably 2,000 to 80,000, can be used. The weight-average molecular weight refers to the weight-average molecular weight in terms of polystyrene analyzed by gel permeation chromatography (GPC). Liquid rubber refers to one that has fluidity at 23°C.

[0107] Resin [F] The polymer composition of the present disclosure may contain a resin (hereinafter also simply referred to as "resin [F]"). The resin [F] may be thermoplastic or thermosetting. From the viewpoint of obtaining a crosslinked product with excellent properties such as strength, abrasion resistance, and crack growth resistance, the resin [F] is preferably at least one selected from the group consisting of a styrene-based resin, polyethylene, a C5-based resin, a hydrogenated C5-based resin, a C9-based resin, a hydrogenated C9 resin, a C5 / C9-based resin, a hydrogenated C5 / C9-based resin, a dicyclopentadiene-based resin, a dicyclopentadiene / C9-based resin, a hydrogenated dicyclopentadiene / C9-based resin, an alkylphenol-based resin, a coumarone-indene resin, a terpene-based resin, and a hydrogenated terpene-based resin. The resin [F] is preferably a thermoplastic resin, and more preferably at least one selected from the group consisting of a styrene-based resin, polyethylene, a C5-based resin, a hydrogenated C5-based resin, a C9-based resin, a hydrogenated C9 resin, a C5 / C9-based resin, a hydrogenated C5 / C9-based resin, a coumarone-indene resin, a terpene-based resin, and a hydrogenated terpene-based resin. As the resin [F], one type may be used alone, or two or more types may be used in combination.

[0108] When the [F] resin is blended into the polymer composition, the blending ratio of the [F] resin is preferably 1 part by mass or more per 100 parts by mass of the rubber component contained in the polymer composition. By blending 1 part by mass or more of the [F] resin, the effect of improving the abrasion resistance, breaking strength, and crack growth resistance of the crosslinked product obtained using the polymer composition by adding the [F] resin can be sufficiently enhanced, which is suitable. When the [F] resin is blended into the polymer composition, the blending ratio of the [F] resin is more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the rubber component. Furthermore, from the viewpoint of maintaining various performance properties of the rubber composition well, the blending ratio of the [F] resin is preferably 100 parts by mass or less, more preferably 70 parts by mass or less, and even more preferably 50 parts by mass or less, per 100 parts by mass of the rubber component contained in the polymer composition. Note that the [F] resin may be used alone or in combination of two or more types.

[0109] [G] Silane Coupling Agent In the present disclosure, the dispersibility of silica can be further improved by blending a silane coupling agent. The silane coupling agent used is not particularly limited, but sulfur-containing silane coupling agents are preferred. Examples of sulfur-containing silane coupling agents include bis(3-triethoxysilylpropyl)tetrasulfide, bis(3-triethoxysilylpropyl)disulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, γ-mercaptopropyltriethoxysilane, 3-octanoylthiopropyltriethoxysilane, 3-[ethoxybis(3,6,9,12,15-pentaoxaoctacosan-1-yloxy)silyl]propane-1-thiol (e.g., Evonik, trade name "Si363"), and mercapto-based silane compounds such as NXT and NXT-Z manufactured by Momentive.

[0110] The amount of silane coupling agent blended is preferably 1 to 20 parts by mass per 100 parts by mass of silica. If the amount of silane coupling agent blended is less than 1 part by mass, the blended amount is too small and the effect of improving the dispersibility of silica may not be sufficiently obtained. On the other hand, if the amount of silane coupling agent blended is more than 20 parts by mass, the processability and elongation at break may decrease. The amount of silane coupling agent blended is more preferably 5 to 15 parts by mass per 100 parts by mass of silica. As the silane coupling agent, one type may be used alone, or two or more types may be used in combination.

[0111] [H] Crosslinking Agent The polymer composition of the present disclosure may contain a crosslinking agent. By containing a crosslinking agent in the polymer composition of the present disclosure, 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 typically being 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 polymer composition.

[0112] The polymer composition may contain a process oil commonly used to extend elastomers. The process oil may be added to the polymer composition, for example, by directly adding the oil during rubber compounding. Suitable process oils include various oils known in the art, such as aromatic oils, paraffinic oils, naphthenic oils, vegetable oils such as soybean oil and sunflower oil, as well as 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 an MES, Vivatec 500 manufactured by H&R Wasag AG as a TDAE, and NC140 manufactured by Japan Energy Corp. The amount of process oil to be 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.

[0113] In addition to the components described above, the polymer composition may contain various additives that are generally used in polymer compositions for producing rubber for tires, such as antioxidants, zinc oxide, stearic acid, softeners, vulcanization accelerators, compatibilizers, vulcanization aids, processing aids, scorch inhibitors, etc. 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.

[0114] The polymer composition of the present disclosure can be applied to various rubber products as a crosslinked body by kneading the polymer components, filler, and other components blended as necessary using a kneader such as an open kneader (e.g., a roll) or an internal kneader (e.g., a Banbury mixer), molding the mixture, and then crosslinking (vulcanizing). Specifically, the crosslinked body of the present disclosure can be applied to various applications, such as tire applications such as tire treads, undertreads, carcasses, sidewalls, and bead portions; sealing materials such as packings, gaskets, weatherstrips, and O-rings; interior and exterior skin materials for various vehicles such as automobiles, ships, aircraft, and railways; building materials; vibration-proof rubbers for industrial machinery and equipment; various hoses and hose covers such as diaphragms, rolls, radiator hoses, and air hoses; belts such as power transmission belts; linings; dust boots; medical device materials; fenders; insulating materials for electric wires; and other industrial products.

[0115] The modified conjugated diene polymer (P) can provide a crosslinked product having excellent physical properties required for tire applications, such as rolling resistance (fuel economy), strength, and abrasion resistance. Therefore, a polymer composition containing the modified conjugated diene polymer (P) can be suitably used as a material for tire treads, sidewalls, or both.

[0116] Tires can be manufactured by conventional methods, for example, by mixing the polymer composition in a kneader, forming a sheet, and then disposing the sheet in a predetermined position (for example, on the outside of the carcass in the case of a sidewall) and vulcanizing the sheet in a conventional manner to form a tread rubber or a sidewall rubber, thereby obtaining a pneumatic tire.

[0117] According to the present disclosure described above in detail, the following means are provided. [Means 1] A modified conjugated diene polymer having a Mooney viscosity measured at 160°C of 80 to 150, and having a partial structure derived from a compound (M) having a nitrogen atom and a hydrocarbyloxysilyl group in one molecule. [Means 2] A modified conjugated diene polymer of [Means 1] having a 1,2-vinyl group content of 60 mass% or less. [Means 3] A modified conjugated diene polymer of [Means 1] or [Means 2] having structural units derived from an aromatic vinyl compound, the content of the structural units derived from the aromatic vinyl compound being 45 mass% or less based on the total amount of structural units possessed by the modified conjugated diene polymer. [Means 4] A modified conjugated diene polymer having a weight average molecular weight measured by gel permeation chromatography of 7.0 x 10 ５ Above 3.0 x 10 ６[Means 5] A modified conjugated diene polymer according to any one of [Means 1] to [Means 4], wherein a molecular weight distribution (Mw / Mn), expressed as the ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) measured by gel permeation chromatography, is 1.60 or more and 4.00 or less. [Means 6] A modified conjugated diene polymer according to any one of [Means 1] to [Means 5], wherein the compound (M) contains a compound having two or more hydrocarbyloxysilyl groups. [Means 7] A method for producing a modified conjugated diene polymer according to any one of [Means 1] to [Means 6], comprising: a polymerization step of polymerizing a monomer containing a conjugated diene compound in the presence of a polymerization initiator to obtain a conjugated diene polymer having an active end; and a modification step of reacting the conjugated diene polymer having an active end with the compound (M). [Means 8] The method for producing a modified conjugated diene polymer according to [Means 7], wherein in the polymerization step, the monomer is polymerized in a solvent in the presence of the polymerization initiator by a continuous polymerization system, and in the modification step, the polymer having the active end is reacted with the compound (M) to obtain a polymer solution, and the method further comprises a desolvation step of removing the solvent from the polymer solution without adding an extender oil to the polymer solution. [Means 9] A rubber veil containing the modified conjugated diene polymer of any of [Means 1] to [Means 6] and not containing an extender oil. [Means 10] A polymer composition containing the modified conjugated diene polymer of any of [Means 1] to [Means 6] and at least one filler selected from the group consisting of silica, carbon black, and the compound represented by formula (1). [Means 11] The polymer composition of [Means 10], further containing at least one rubber component selected from the group consisting of natural rubber, isoprene rubber, butadiene rubber, emulsion-polymerized styrene-butadiene rubber, solution-polymerized styrene-butadiene rubber, hydrogenated styrene-butadiene rubber, butyl rubber, halogenated butyl rubber, ethylene-propylene rubber, and ethylene-butadiene rubber, which is different from the modified conjugated diene polymer. [Means 12] The polymer composition of [Means 10] or [Means 11], further containing a resin. [Means 13] A crosslinked product obtained by crosslinking the polymer composition of any of [Means 10] to [Means 12].[Means 14] A tire in which one or both of a tread and a sidewall are made using the polymer composition of any one of [Means 10] to [Means 12].

[0118] The present invention will be described in detail below based on examples, but is not limited to the following examples. In the following synthesis examples, 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.

[0119] Bound styrene content (%): Using deuterated chloroform as a solvent, １ Calculated by H-NMR measurement. Vinyl group content (%): 400 MHz １Calculated by H-NMR measurement. Weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of polymer: A chart (GPC curve) based on the molecular weight in terms of polystyrene was obtained by gel permeation chromatography (GPC), and the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the polymer were determined based on the obtained chart. Specific measurement conditions for GPC are as follows. (GPC measurement conditions) Measuring instrument: HLC-8020 (manufactured by Tosoh Corporation) Column: Two GMH-HR-H (manufactured by Tosoh Corporation) connected in series Detector: Differential refractometer RI-8020 (manufactured by Tosoh Corporation) Eluent: Tetrahydrofuran Column temperature: 40°C Flow rate: 1.0 mL / min Sample concentration: 10 mg / 20 mL Mooney viscosity (ML1+4, 160°C): Measured under the conditions described in JIS K6300-1, except that the measurement temperature was 160°C. Specifically, measurements were performed using an L rotor under the following conditions: 1 minute of preheating, 4 minutes of rotor operation, and a temperature of 160°C. Water content: 10 g of a modified conjugated diene polymer was placed in a halogen heater heated to 110°C and heated until the sample mass change rate was less than 1 mg / 90 seconds. The water content of the sample (hereinafter also referred to as "VM") was calculated from the mass change after heating. The formula for calculating VM is as follows: VM (mass%) = (sample mass before heating - sample mass after heating) / sample mass before heating × 100. Glass transition temperature: In accordance with JIS K6240:2011, the glass transition temperature was determined from the inflection point of the DSC curve in the range of -100°C to 40°C. Specific measurement conditions for the glass transition temperature are as follows: (DSC measurement conditions) Measuring device: Q1000 Differential Scanning Calorimeter (DSC) (manufactured by TA Instruments) Heating rate: 10°C / min. Stain resistance of veil: A migration staining test (accelerated heating method) was performed in accordance with JIS K6267: 2006. The presence or absence of staining on the stained material was confirmed visually.

[0120] Example 1 Synthesis of Modified Conjugated Diene Polymer A-1 To a 50-liter autoclave reactor (first reactor), 85.4 g / min of 1,3-butadiene and 24.4 g / min of styrene as monomers, 830.6 g / min of cyclohexane as a solvent, 0.6 g / min of tetrahydrofuran as a vinyl content adjuster (randomizer), and 62.3 mg / min of n-butyllithium as a polymerization initiator were continuously charged, and the temperature inside the reactor was controlled at 77°C. After additionally adding 1,3-butadiene at a rate of 12.2 g / min, the polymer solution was continuously discharged from the first reactor at a rate of 953.3 g / min, and 1,1'-(1,4-phenylene)bis(N-(3-(triethoxysilyl)propyl)methanimine (hereinafter referred to as "compound N-Si-1") was added to the discharged polymer solution at a rate of 116.0 mg / min, and the solution was continuously introduced into the second reactor to carry out the reaction. Di-tert-butyl-p-cresol was then added in an amount of 0.88 parts by mass relative to 100 parts by mass of the polymer to obtain a polymer solution. The obtained polymer solution was then used as is to remove the solvent by steam stripping, and dried with a heated roll adjusted to 110°C to obtain a modified conjugated diene polymer A-1. A portion of the dried modified conjugated diene polymer was used to produce a bale by the molding method described below.

[0121] <Method of molding rubber bale> 20 kg of the modified conjugated diene polymer A-1 obtained above was compressed for 12 seconds at a molding pressure of 10 MPa and a molding temperature of 60°C to obtain a rectangular bale of modified conjugated diene polymer A-1.

[0122] Table 1 shows various physical property values ​​of the modified conjugated diene polymer A-1. In Table 1, "-" indicates that the reagent was not added to the polymerization system. Regarding the evaluation results of the stain resistance of the veil, Table 1 indicates that the stained material after the test has not discolored or has only slightly discolored compared to before the test, with an "A" indicating that the stained material after the test has discolored moderately or significantly compared to before the test (the same applies to Table 2). If the stained material after the test has not discolored or has only slightly discolored compared to before the test, the veil can be evaluated as having excellent stain resistance.

[0123] [Examples 2 to 17: Synthesis of modified conjugated diene polymers A-2 to A-17] Polymerization, desolvation, and drying were carried out in the same manner as in Example 1, except that the types and amounts of reagents used were as shown in Tables 1 and 2, to obtain modified conjugated diene polymers A-2 to A-17. In addition, bales were produced using each of the modified conjugated diene polymers A-2 to A-17. The physical properties of the obtained modified conjugated diene polymers A-2 to A-17 are shown in Tables 1 and 2.

[0124] Comparative Example 1 Synthesis of Modified Conjugated Diene Polymer A-18 The types and amounts of reagents used were as shown in Table 2, and polymerization, desolvation, and drying were carried out in the same manner as in Example 1, except that extender oil (Process Oil T-DAE, manufactured by ENEOS Corporation) was added at a rate of 18.3 g / min to the polymer solution containing the produced modified conjugated diene polymer, thereby obtaining modified conjugated diene polymer A-18. Bales were also produced using the modified conjugated diene polymer A-18.

[0125] Comparative Examples 2 and 3: Synthesis of modified conjugated diene polymers A-19 and A-20 Modified conjugated diene polymers A-19 and A-20 were obtained by polymerization, desolvation, and drying in the same manner as in Example 1, except that the types and amounts of reagents used were as shown in Table 2. Bales were also produced using each of the modified conjugated diene polymers A-19 and A-20.

[0126] Comparative Example 4 Synthesis of Conjugated Diene Polymer A-21 To a reactor (first reactor) having an internal volume of 50 L, 1,3-butadiene as monomers were continuously charged at a rate of 42.1 g / min, styrene at a rate of 29.9 g / min, cyclohexane as a solvent at a rate of 415.9 g / min, tetrahydrofuran as a vinyl content adjuster (randomizer) at a rate of 26.9 g / min, and n-butyllithium as a polymerization initiator at a rate of 26.5 mg / min, and the temperature inside the reactor was controlled at 70° C. The polymer solution was continuously decharged from the first reactor at a rate of 518.6 g / min, and silicon tetrachloride (SiCl ４ ) was added at a rate of 11.7 mg / min, and the mixture was continuously introduced into the second reactor and reacted. At the outlet of the second reactor, di-tert-butyl-p-cresol was added in an amount of 0.88 parts by mass per 100 parts by mass of the polymer, to obtain a polymer solution. To the produced polymer solution containing the conjugated diene polymer, extender oil (ENEOS Corporation, process oil T-DAE) was added at a rate of 28.4 g / min, and the resulting polymer solution was then desolvated by steam stripping and dried with a heated roll adjusted to 110°C, to obtain conjugated diene polymer A-21. Furthermore, bales were produced using the modified conjugated diene polymer A-21.

[0127] Comparative Example 5: Synthesis of Modified Conjugated Diene Polymer A-22 A 5-liter autoclave reactor purged with nitrogen was charged with 2,000 g of cyclohexane, 31.6 g of tetrahydrofuran, 122 g of styrene, and 320 g of 1,3-butadiene. The temperature of the reactor contents was adjusted to 10°C, and 4.75 mmol of n-butyllithium was added as a polymerization initiator to initiate polymerization. The polymerization was carried out under adiabatic conditions, with the maximum temperature reaching 85°C. After the polymerization conversion rate reached 99%, 10 g of 1,3-butadiene was added over 2 minutes, and then 2.12 mmol of compound N-Si-1 was added and the reaction was carried out for 15 minutes. 3.96 g of 2,6-di-tert-butyl-p-cresol was added to the resulting polymer solution containing the modified conjugated diene polymer. Next, the solvent was removed by steam stripping, and the resulting mixture was dried with a heated roll adjusted to 110° C. to obtain a modified conjugated diene polymer A-22. Bales were also produced using the modified conjugated diene polymer A-22.

[0128]

[0129]

[0130] Details of the abbreviations in Tables 1 and 2 are as follows: (Initial end-modifying agents) INI-1 to INI-4: Compounds represented by the following formulas (INI-1) to (INI-4), respectively INI-5: Piperidine INI-6: N-trimethylsilylpiperazine

[0131] (Branching agent) Si-1: trimethoxy(4-vinylphenyl)silane (Terminator modifier) ​​N-Si-1 to N-Si-5: compounds represented by the following formulas (N-Si-1) to (N-Si-5), respectively

[0132] Examples 18 to 41, Comparative Examples 6 to 14 Polymer compositions P-1 to P-33 were produced by blending the components according to the formulations shown in Tables 3 to 5 and melt-kneading the blends. Kneading was carried out in the following manner. Using a batch mixer (manufactured by Toyo Seiki Seisakusho; trade name: Labo Plastomill) equipped with a temperature control device, in the first stage of kneading, the rubber components ((modified) conjugated diene polymer, polybutadiene rubber, natural rubber), extender oil, silica, silane coupling agent, carbon black, thermoplastic resin, stearic acid, antioxidant, and zinc oxide were blended and kneaded under the conditions of a set temperature of 100°C, a rotation speed of 60 rpm, and a kneading time of 5 minutes. The temperature of the kneaded mixture discharged from the mixer was always around 150°C. Next, in the second stage of kneading, the kneaded material obtained in the first stage of kneading was cooled to room temperature, and then a vulcanization accelerator and sulfur were added to the mixer. The temperature was adjusted to 70°C, the rotation speed was 60 rpm, and the kneading time was 1.5 minutes to obtain each polymer composition. The temperature of the kneaded material discharged from the mixer was 100°C or below when discharged. Next, each obtained polymer composition was vulcanized and molded in a vulcanization press at 160°C for a predetermined time to obtain a vulcanized rubber as a crosslinked product. The following physical property evaluations were performed using the obtained vulcanized rubber. The results are shown in Table 2. Note that in Comparative Example 8, the processability of the polymer composition was poor, and a polymer composition and vulcanized rubber suitable for evaluation could not be obtained.

[0133] Loss tangent (3% tan δ @ 50°C rolling resistance) Using vulcanized rubber as the measurement sample, the ratio of the loss modulus G" to the storage modulus G' (50°C tan δ) was measured using a shear-type dynamic spectrometer (manufactured by TA Instruments) under conditions of an angular velocity of 100 radians per second, a temperature of 50°C, and a shear strain of 3%. Examples 18 to 37 and Comparative Examples 7 to 10 are shown as indexes with Comparative Example 6 set to 100. Example 38 is shown as an index with Comparative Example 11 set to 100, Example 39 is shown as an index with Comparative Example 12 set to 100, Example 40 is shown as an index with Comparative Example 13 set to 100, and Example 41 is shown as an index with Comparative Example 14 set to 100. The larger the value, the smaller the rolling resistance and the better the fuel economy performance. Tensile strength ((TB * EB) / 2) Using vulcanized rubber as the measurement sample, a tensile test was conducted in accordance with JIS K6251:2010. Here, using a dumbbell-shaped No. 3 specimen, the stress at break (TB, MPa) and elongation at break (EB, %) were measured at room temperature. The larger the TB and EB values, the greater the breaking strength, indicating a higher and better mechanical strength of the material. Strength was calculated according to the formula (TB * EB) / 2. The measurement results for Examples 18 to 37 and Comparative Examples 7 to 10 are expressed as an index, with Comparative Example 6 set to 100. Furthermore, Comparative Example 11 for Example 38, Comparative Example 12 for Example 39, Comparative Example 13 for Example 40, and Comparative Example 14 for Example 41 are also expressed as an index, with the index set to 100. The larger the index, the higher the tensile strength, indicating a better result. Abrasion Resistance (Lambourn Abrasion Test) Using vulcanized rubber as the test sample, measurements were performed using a Lambourn abrasion tester (manufactured by Ueshima Seisakusho Co., Ltd.) in accordance with JIS K6264, at a load of 44.1 N, a slip ratio of 25%, and 25°C. Examples 18 to 37 and Comparative Examples 7 to 10 are shown as indexes with Comparative Example 6 set to 100. Example 38 is shown as an index with Comparative Example 11 set to 100, Example 39 is shown as an index with Comparative Example 12 set to 100, Example 40 is shown as an index with Comparative Example 13 set to 100, and Example 41 is shown as an index with Comparative Example 14 set to 100. The larger the value, the better the wear resistance.

[0134]

[0135]

[0136]

[0137] Details of the abbreviations in Tables 3 to 5 are as follows: *1: ENEOS Materials, trade name "BR01" *2: ENEOS, trade name "NC-140" *3: Silica 1: Rhodia, trade name "ZEOSIL 1165MP", Silica 2: Evonik, trade name "ULTRASIL 9100GR", Silica 3: Evonik, trade name "ULTRASIL VN3" *4: Evonik, trade name "Si75" *5: Tokai Carbon, SEA ST 3 *6: Resin 1: ENEOS, T-REZ PR802 (C5 / C9 resin), Resin 2: ENEOS, T-REZ PR803 (hydrogenated DCPD / C9 resin) *7: N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, trade name "Ozonone 6C", manufactured by Seiko Chemical Co., Ltd. *8: 1,3-diphenylguanidine, trade name "Noccela D", manufactured by Ouchi Shinko Chemical Industry Co., Ltd. *9: N-cyclohexyl-2-benzothiazolyl sulfenamide, trade name "Noccela CZ", manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0138] As shown in Tables 3 to 5, it was found that the polymer compositions P-1 to P-20 and P-26, P-28, P-30, and P-32 of Examples 18 to 41, which contained the modified conjugated diene-based polymers of Examples 1 to 17, could provide crosslinked products having a well-balanced improvement in rolling resistance, abrasion resistance, and strength. More specifically, according to the polymer compositions P-1 to P-10 of Examples 18 to 27, which contained modified conjugated diene polymers A-1 to A-3, A-6 to A-8, A-10, A-11, A-13, and A-14, each of which used only a terminal end-modifier as the compound (M) during polymerization and had a 160°C Mooney viscosity in the range of 80 to 150, a crosslinked product with improved and well-balanced rolling resistance, abrasion resistance, and strength could be obtained, as compared with the polymer compositions P-21, P-22, P-24, and P-25 of Comparative Examples 6, 7, 9, and 10, each of which contained (modified) conjugated diene polymers A-18 to A-22, each of which had a 160°C Mooney viscosity outside the range of 80 to 150, instead of the modified conjugated diene polymers A-1 to A-3, A-6 to A-8, A-10, A-11, A-13, and A-14.

[0139] Furthermore, crosslinked bodies having a well-balanced improvement in rolling resistance, abrasion resistance, and strength were also obtained using polymer compositions P-11 to P-14 of Examples 28 to 31, which used an initiating end-modifier and a terminating end-modifier as compound (M) and contained modified conjugated diene polymers A-4, A-5, A-9, and A-12 having Mooney viscosities at 160°C in the range of 80 to 150. Furthermore, comparison of the results of Example 18 with those of Examples 28 and 29 revealed that the rolling resistance and abrasion resistance could be further improved by further using an initiating end-modifier as compound (M).

[0140] Furthermore, in the polymer compositions P-15 to P-18 of Examples 32 to 35, which used modified conjugated diene polymers A-15 to A-17 in which the styrene content and 1,2-vinyl content of the modified conjugated diene polymer were changed, significant improvements were observed particularly in tensile strength and abrasion resistance. Furthermore, when no resin was added, significant improvements were observed in rolling resistance while improving tensile strength and abrasion resistance (Examples 36 and 37).

[0141] Furthermore, comparisons between Example 38 and Comparative Example 11, Example 39 and Comparative Example 12, Example 40 and Comparative Example 13, and Example 41 and Comparative Example 14 revealed that a crosslinked product having a well-balanced improvement in rolling resistance, abrasion resistance, and strength can be obtained even when only a terminal end-modifier is used as compound (M), a modified conjugated diene polymer having a Mooney viscosity at 160°C in the range of 80 to 150 is used, and natural rubber is used in combination as the rubber component. The bales formed from the modified conjugated diene polymers of Examples 1 to 17 also had excellent stain resistance.

Claims

1. A modified conjugated diene polymer having a partial structure derived from a compound (M) having a nitrogen atom and a hydrocarbyloxysilyl group in one molecule, and having a Mooney viscosity measured at 160°C of 80 or more and 150 or less.

2. The modified conjugated diene polymer according to claim 1, having a 1,2-vinyl group content of 60% by mass or less.

3. A modified conjugated diene polymer according to claim 1, which has structural units derived from an aromatic vinyl compound, and the content of the structural units derived from the aromatic vinyl compound is 45 mass% or less based on the total amount of structural units contained in the modified conjugated diene polymer.

4. The weight average molecular weight measured by gel permeation chromatography is 7.0 x 10 ５ Above 3.0 x 10 ６ The modified conjugated diene polymer according to claim 1, wherein:

5. The modified conjugated diene polymer according to claim 1, having a molecular weight distribution (Mw / Mn) expressed as the ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) measured by gel permeation chromatography of 1.60 or more and 4.00 or less.

6. The modified conjugated diene polymer according to claim 1, wherein the compound (M) includes a compound having two or more hydrocarbyloxysilyl groups.

7. A method for producing a modified conjugated diene polymer according to any one of claims 1 to 6, comprising: a polymerization step of polymerizing a monomer containing a conjugated diene compound in the presence of a polymerization initiator to obtain a conjugated diene polymer having an active end; and a modification step of reacting the conjugated diene polymer having an active end with the compound (M).

8. The method for producing a modified conjugated diene-based polymer according to claim 7, further comprising: in the polymerization step, polymerization of the monomer is carried out in a solvent in the presence of the polymerization initiator by a continuous polymerization method; in the modification step, the polymer having the active end is reacted with the compound (M) to obtain a polymer solution; and a desolvation step of removing the solvent from the polymer solution without adding an extender oil to the polymer solution.

9. A rubber veil comprising the modified conjugated diene polymer according to any one of claims 1 to 6 and containing no extender oil.

10. A polymer composition comprising the modified conjugated diene polymer according to any one of claims 1 to 6, and at least one filler selected from the group consisting of silica, carbon black, and a compound represented by the following formula (1): １ mSiO ｋ ・iH ２ O...(1) (In formula (1), M １ is at least one selected from the group consisting of a specific metal, which is any one of aluminum, magnesium, titanium, zirconium, and calcium, an oxide of the specific metal, a hydroxide of the specific metal, and a carbonate of the specific metal. n is an integer of 1 to 5, m is an integer of 0 to 10, k is an integer of 2 to 5, and i is an integer of 0 to 10.

11. The polymer composition according to claim 10, further comprising at least one rubber component selected from the group consisting of natural rubber, isoprene rubber, butadiene rubber, emulsion-polymerized styrene-butadiene rubber, solution-polymerized styrene-butadiene rubber, hydrogenated styrene-butadiene rubber, butyl rubber, halogenated butyl rubber, ethylene-propylene rubber, and ethylene-butadiene rubber, which is different from the modified conjugated diene polymer.

12. The polymer composition of claim 10, further comprising a resin.

13. A crosslinked product obtained by crosslinking the polymer composition according to claim 10.

14. A tire having a tread and / or sidewalls made from the polymer composition of claim 10.

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