Abstract: A method for producing a rubber composition may include: mixing modified silica (B), pre-prepared by surface treatment of unmodified silica, with a modified conjugated diene-based polymer (A) and a polymer having crystalline character (C). A crosslinked product may be produced through crosslinking a rubber composition obtained from such a method. The crosslinked product may be used for producing a tire including a tread and a sidewall, wherein at least one of the tread and the sidewall is formed of the crosslinked product.

Abstract: A rubber composition contains (A) a modified conjugated diene-based polymer, (B) modified silica, and (C) a polymer having crystalline character. A crosslinked product is produced through crosslinking of the rubber composition containing the modified conjugated diene-based polymer (A), the modified silica (B), and the polymer having crystalline character (C). The crosslinked product is used for producing a tire including a tread and a sidewall, wherein at least one of the tread and the sidewall is formed of the crosslinked product.

Abstract: A method for producing a rubber composition may include: mixing modified silica (B), pre-prepared by surface treatment of unmodified silica, with a modified conjugated diene-based polymer (A) and a polymer having crystalline character (C). A crosslinked product may be produced through crosslinking a rubber composition obtained from such a method. The crosslinked product may be used for producing a tire including a tread and a sidewall, wherein at least one of the tread and the sidewall is formed of the crosslinked product.

Abstract: A rubber composition contains: (A) a polymer having a carbon-carbon unsaturated bond and exhibiting a value ? of 0.6 or more as obtained by the following formula (i): ?=(p+(0.5×r))/(p+q+(0.5×r)+s)??(i) wherein p, q, r, and s are the proportions by mole of structural units represented by the following formulae (1), (2), (3), and (4), respectively in the polymer: and (B) modified silica.

Abstract: A production process of a rubber composition containing a modified conjugated diene-based polymer, which can provide a rubber composition in which processability is excellent, and a filling agent, when contained, has favorable dispersibility therein. The production process of the rubber composition includes: a first step of kneading a modified conjugated diene-based polymer that is obtained by polymerizing a monomer containing a conjugated diene compound and has at least one nitrogen-containing functional group selected from a primary amino group, a secondary amino group, a tertiary amino group and groups in which these amino groups have been converted into an onium group, and a basic compound having an acid dissociation constant of 8.0 or more; and a second step of kneading the kneaded product obtained in the first step and a cross-linking agent.

Abstract: The present invention has as its object the provision of a production process of a rubber composition containing a modified conjugated diene-based polymer, which can provide a rubber composition in which processability is excellent, and a filling agent, when contained, has favorable dispersibility therein. The production process of a rubber composition according to the present invention includes: a first step of kneading a modified conjugated diene-based polymer that is obtained by polymerizing a monomer containing a conjugated diene compound and has at least one nitrogen-containing functional group selected from the group consisting of a primary amino group, a secondary amino group, a tertiary amino group and groups in which these amino groups have been converted into an onium group, and a basic compound having an acid dissociation constant of 8.0 or more; and a second step of kneading the kneaded product obtained in the first step and a cross-linking agent.

Abstract: A rubber composition contains: (A) a polymer having a carbon-carbon unsaturated bond and exhibiting a value ? of 0.6 or more as obtained by the following formula (i): ?=(p+(0.5×r))/(p+q+(0.5×r)+s)??(i) wherein p, q, r, and s are the proportions by mole of structural units represented by the following formulae (1), (2), (3), and (4), respectively in the polymer: and (B) modified silica.

Abstract: A rubber composition contains (A) a modified conjugated diene-based polymer, (B) modified silica, and (C) a polymer having crystalline character. A crosslinked product is produced through crosslinking of the rubber composition containing the modified conjugated diene-based polymer (A), the modified silica (B), and the polymer having crystalline character (C). The crosslinked product is used for producing a tire including a tread and a sidewall, wherein at least one of the tread and the sidewall is formed of the crosslinked product.

Abstract: A modified conjugated diene-based polymer is produced by reacting a conjugated diene-based polymer having an alkali metal or an alkali-earth metal at a terminal of the polymer with a compound represented by formula (1). R1 and R2 independently represent a hydrocarbyl group having 20 or fewer carbon atoms. R3 represents a substituted alkyl group having 20 or fewer carbon atoms prepared through substitution of at least one of a hydrogen atom and —CH2— of an alkyl group by a group containing only at least one heteroatom selected from the group consisting of nitrogen, phosphorus, oxygen, and sulfur, or a monovalent aromatic group having 20 or fewer carbon atoms and containing at least one element selected from the group consisting of nitrogen, phosphorus, oxygen, and sulfur, with the proviso that R3 does not have active hydrogen. R4 represents an alkanediyl group having 20 or fewer carbon atoms. n is 1 or 2.

Abstract: A modified conjugated diene-based polymer is produced by reacting a conjugated diene-based polymer having an alkali metal or an alkali-earth metal at a terminal of the polymer with a compound represented by formula (1). R1 and R2 independently represent a hydrocarbyl group having 20 or fewer carbon atoms. R3 represents a substituted alkyl group having 20 or fewer carbon atoms prepared through substitution of at least one of a hydrogen atom and —CH2— of an alkyl group by a group containing only at least one heteroatom selected from the group consisting of nitrogen, phosphorus, oxygen, and sulfur, or a monovalent aromatic group having 20 or fewer carbon atoms and containing at least one element selected from the group consisting of nitrogen, phosphorus, oxygen, and sulfur, with the proviso that R3 does not have active hydrogen. R4 represents an alkanediyl group having 20 or fewer carbon atoms. n is 1 or 2.

Abstract: A modified conjugated diene polymer obtained by modifying a conjugated diene polymer that is obtained by polymerizing a conjugated diene compound or polymerizing a conjugated diene compound and an aromatic vinyl compound is produced by a production method comprising a first modification step wherein an unsaturated binding site at least either in the skeleton or at the side chain of the conjugated diene polymer is reacted with a first compound having a group 4 or 13 element of the periodic table.

Abstract: A modified conjugated diene-based polymer is produced that is a modified product of a conjugated diene-based polymer obtained by polymerizing a conjugated diene compound, or polymerizing a conjugated diene compound and an aromatic vinyl compound, in the presence of an alkali metal compound or an alkaline-earth metal compound. The modified conjugated diene-based polymer is produced by a production method that includes a main chain modification step that reacts at least either an unsaturated bond or a functional group that is included in a terminal-modified polymer and is not situated at a terminal of the terminal-modified polymer, with a specific compound that includes a functional group that interacts with silica, the terminal-modified polymer being obtained by introducing a functional group that interacts with silica into at least one terminal of the conjugated diene-based polymer.

Abstract: A modified conjugated diene-based polymer is produced by reacting a conjugated diene-based polymer having an alkali metal or an alkali-earth metal at a terminal of the polymer with a compound represented by formula (1). R1 and R2 independently represent a hydrocarbyl group having 20 or fewer carbon atoms. R3 represents a substituted alkyl group having 20 or fewer carbon atoms prepared through substitution of at least one of a hydrogen atom and —CH2— of an alkyl group by a group containing only at least one heteroatom selected from the group consisting of nitrogen, phosphorus, oxygen, and sulfur, or a monovalent aromatic group having 20 or fewer carbon atoms and containing at least one element selected from the group consisting of nitrogen, phosphorus, oxygen, and sulfur, with the proviso that R3 does not have active hydrogen. R4 represents an alkanediyl group having 20 or fewer carbon atoms.

Abstract: A method for producing a modified conjugated diene polymer, comprises polymerizing (i) a monomer comprising a conjugated diene compound, or (ii) a monomer comprising a conjugated diene compound and an aromatic vinyl compound, in the presence of: at least one compound selected from the group consisting of formulae (1) and (2), and an alkali metal compound or an alkaline earth metal compound. A1 is a functional group which has a hydrocarbylsilyl group in which three hydrogen atoms in a —SiH3 structure are each substituted by a hydrocarbyl group; has at least one atom selected from the group consisting of N, P and S; and has no active hydrogen and is bound to R1 by any one atom of the N, P and S. R1 and R2 are hydrocarbylene groups.

Abstract: The invention provides a rubber composition which can improve low fuel consumption performance, workability, and abrasion resistance at the same time in uses of automobile tires and the like. A modified conjugated diene polymer is produced by a method comprising: a polymerization step of polymerizing a conjugated diene compound or polymerizing a conjugated diene compound and an aromatic vinyl compound to obtain a conjugated diene polymer having an active end in the presence of a metal amide compound obtained by mixing an alkali metal compound or an alkaline earth metal compound with a secondary amine compound and a first modification step of reacting the active end with a compound (C1) having a functional group (a) that interacts with silica, having one or more linear structures where three or more groups or atoms in total derived from at least either of a methylene group and a divalent atom are linearly connected, and capable of binding to a plurality of the active ends.

Abstract: A modified conjugated diene polymer obtained by modifying a conjugated diene polymer that is obtained by polymerizing a conjugated diene compound or polymerizing a conjugated diene compound and an aromatic vinyl compound is produced by a production method comprising a first modification step wherein an unsaturated binding site at least either in the skeleton or at the side chain of the conjugated diene polymer is reacted with a first compound having a group 4 or 13 element of the periodic table.

Abstract: A method for producing a modified conjugated diene polymer usable as a raw material of a crosslinked polymer which is used for use in tires and the like of automobiles and can enhance low fuel consumption performance of automobiles and the like is provided. A method for producing a modified conjugated diene polymer comprising a polymerization step in which a monomer including a conjugated diene compound or a monomer including a conjugated diene compound and an aromatic vinyl compound is polymerized in the presence of at least one compound selected from the group consisting of the following formulae (1) and (2) and an alkali metal compound or an alkaline earth metal compound to obtain a modified conjugated diene polymer. (In the formulae, A1 is a hydrocarbylsilyl group in which three H's (hydrogen atoms) in a “—SiH3” structure are each substituted by a hydrocarbyl group, and R1 and R2 are hydrocarbylene groups.

Abstract: A modified conjugated diene-based polymer is produced that is a modified product of a conjugated diene-based polymer obtained by polymerizing a conjugated diene compound, or polymerizing a conjugated diene compound and an aromatic vinyl compound, in the presence of an alkali metal compound or an alkaline-earth metal compound. The modified conjugated diene-based polymer is produced by a production method that includes a main chain modification step that reacts at least either an unsaturated bond or a functional group that is included in a terminal-modified polymer and is not situated at a terminal of the terminal-modified polymer, with a specific compound that includes a functional group that interacts with silica, the terminal-modified polymer being obtained by introducing a functional group that interacts with silica into at least one terminal of the conjugated diene-based polymer.

Abstract: A modified conjugated diene polymer, which can be used as a raw material of a cross-linked polymer for automobile tires, is prepared by a method including a step of polymerizing a monomer having a conjugated diene compound etc. in the presence of a compound of formula (1) or (2) and an alkali metal compound to obtain a conjugated diene polymer, and a step of reacting the polymer and a compound of formula (3). In formulae (1) and (2), R1 is hydrocarbylene; Q is —N(-A1)- etc.; A1 is hydrocarbyl without active hydrogen atom and may have substituent(s). In formula (3), E is a functional group etc. which has no active hydrogen atom and is bound to R4 by an atom of N; R2 and R3 are hydrocarbyl groups; R4 is a hydrocarbylene group; and n is an integer of 0 to 2.

Abstract: A method for producing a conjugated diene polymer usable as a raw material of a crosslinked polymer which is used for use in tires of automobiles and can enhance low fuel consumption performance of automobiles is provided. A method for producing a modified conjugated diene polymer comprising a polymerization step in which monomer including a conjugated diene compound or monomer including a conjugated diene compound and an aromatic vinyl compound are polymerized in the presence of at least one compound selected from the group consisting of the following formulae (1) and (2) and an alkali metal compound or an alkaline earth metal compound to obtain a modified conjugated diene polymer. (In the formulae, A1 is a functional group which has a three-substituted hydrocarbylsilyl group; has at least one atom selected from the group consisting of N, P and S; has no active hydrogen and is bound to R1 by any one atom of the above N, P and S. R1 and R2 are hydrocarbylene groups.