Abstract: A method for producing a modified conjugated diene polymer includes a modification step (A) that subjects a conjugated diene polymer having a cis-1,4-bond content of 98.5% or more and possessing an active end to a modification reaction to introduce an alkoxysilane compound having two or more reactive groups including an alkoxysilyl group into the active end of the conjugated diene polymer, and a condensation step (B) that subjects the residue of the alkoxysilane compound introduced into the active end to a condensation reaction in the presence of a condensation catalyst that includes at least one element among the elements of the groups 4A, 2B, 3B, 4B, and 5B in the periodic table. The method can produce a modified conjugated diene polymer that exhibits low heat build-up and excellent wear resistance.

Abstract: A method for producing a modified conjugated diene polymer includes carrying out a modification reaction that reacts a modifier that includes a specific compound with a conjugated diene polymer having a cis-1,4-bond content of 98.5% or more and possessing an active end to introduce the modifier into the active end of the conjugated diene polymer to obtain a modified conjugated diene polymer. The modified conjugated diene polymer that exhibits excellent wear resistance, excellent mechanical properties, and reduced cold flow can be obtained by the method.

Abstract: A process for producing a modified conjugated diene polymer includes subjecting an active terminal of a conjugated diene polymer having a vinyl content of less than 10% and a cis-1,4 bond content of 75% or more to a modification reaction with an alkoxysilane compound, and subjecting the alkoxysilane compound (residue) to a condensation reaction in an aqueous solution at a pH of 9 to 14 and a temperature of 85 to 180° C. in the presence of a condensation accelerator including a compound containing titanium. The modified conjugated diene polymer exhibits low heat build-up and increased reinforcing properties when used for a rubber composition, and exhibits excellent wear resistance, mechanical characteristics, and processability.

Abstract: A method for preparing a functionalized polymer comprising the steps of preparing a pseudo-living polymer by polymerizing conjugated diene monomer with a lanthanide-based catalyst, and reacting the pseudo-living polymer with at least one functionalizing agent defined by the formula (I) where A is a substituent that will undergo an addition reaction with a pseudo-living polymer, R1 is a divalent organic group, R2 is a monovalent organic group, and each R4, which may be the same or different, is a monovalent organic group or a substituent defined by —OR5 where R5 is a monovalent organic group, with the proviso that A, R1, R2, R4, and R5 are substituents that will not protonate a pseudo-living polymer. Also, the functionalized polymer and a vulcanizable composition containing the polymer.

Abstract: The method for producing a modified conjugated diene based (co)polymer, according to the present invention comprises a step of reacting a conjugated diene based (co)polymer with a metal halide compound to obtain a modified conjugated diene based (co)polymer, the conjugated diene based (co)polymer having a weight-average molecular weight of 150,000 to 2,000,000 and being obtained by bonding, to a polymer having at least a conjugated diene unit, an alkoxysilyl group and an optionally protected primary amino group. The method can satisfactorily produce a conjugated diene based (co)polymer which has a high Mooney viscosity, excellent shape stability and good processability.

Abstract: A conjugated diolefin copolymer rubber is produced by copolymerization of a conjugated diolefin and an aromatic vinyl compound and has a primary amino group and an alkoxysilyl group bonded to the copolymer chain. The conjugated diolefin copolymer rubber contains the aromatic vinyl compound in an amount of 5 to 60 wt %. The aromatic vinyl compound is densely distributed in one terminal of the copolymer chain, and is scarcely distributed in the other terminal. The conjugated diolefin copolymer rubber has a temperature difference (?Tg) of 25° C. or more. The conjugated diolefin copolymer rubber has low hysteresis loss properties as well as improved abrasion resistance, rupture characteristics, and road grip characteristics without impairing wet skid characteristics. A method for producing the conjugated diolefin copolymer rubber is also disclosed.

Abstract: The method for producing a modified conjugated diene based (co)polymer, according to the present invention comprises (a) obtaining a primarily modified polymer by carrying out a primary modification reaction wherein at least one member selected from the group consisting of an alkoxysilane compound and a silanol compound is introduced into the active alkali metal terminal of a conjugated diene based (co)polymer having an active alkali metal terminal, and (b) obtaining a secondarily modified polymer (a modified conjugated diene based (co)polymer) by subjecting the above-obtained primarily modified polymer to reactions comprising (b1) and (b2). (b1): a reaction with a condensation accelerator comprising a metal element. (b2): a reaction with at least one member selected from the group consisting of inorganic acids and metal halides.

Abstract: A method for producing a modified conjugated diene polymer includes a step (A) carrying out a primary modification reaction that reacts a heterocumulene compound having two or more specific functional groups with a conjugated diene polymer having a vinyl content of below 10% and a cis-1,4-bond content of 75% or more and possessing an active end to obtain a primary-modified conjugated diene polymer, and a step (B) carrying out a secondary modification reaction that reacts an active hydrogen-containing compound that includes one or more functional groups selected from the group consisting of an amino group, an imino group, a mercapto group, and a hydroxyl group with the primary-modified conjugated diene polymer to obtain a secondary-modified conjugated diene polymer. The method can produce a modified conjugated diene polymer that exhibits low heat build-up (low fuel consumption) and excellent wear resistance.

Abstract: A method for preparing a functionalized polymer comprising the steps of preparing a polymer by polymerizing conjugated diene monomer with a lanthanide-based catalyst, wherein the lanthanide-based catalyst comprises (a) a lanthanide compound, (b) an alkylating agent, and (c) a source of halogen, and reacting the pseudo-living polymer with at least one amide-containing functionalizing agent.

Abstract: A process for producing a modified polymer which increases low heat buildup and reinforcing capability of a rubber composition and which has excellent abrasion resistance, mechanical characteristics, and processability; a modified polymer obtained by the process; and a rubber composition using the modified polymer are provided. The process comprises a step of carrying out a modification reaction on the active end of a conjugated diene polymer having a vinyl content of below 10%, a cis-1,4 bond content of 75% or higher, and an active end, using an alkoxysilane compound, and a step of carrying out a condensation reaction in the presence of a condensation accelerator comprising a compound of an element belonging to at least one of the groups 4A (excluding Ti), 2B, 3B, and 5B of the periodic table.

Abstract: A process for producing a modified polymer that exhibits low rolling resistance, excellent mechanical properties (e.g., tensile strength), high wet-skid resistance, and excellent wear resistance when vulcanized, a modified polymer obtained by the process, and a rubber composition containing the same. The process includes subjecting an alkali metal active end of a conjugated diene polymer to a modification reaction with an alkoxysilane compound, the conjugated diene polymer being produced by subjecting a diene monomer or a diene monomer and a monomer other than the diene monomer to anionic polymerization in a hydrocarbon solvent using an alkali metal initiator, and subjecting the resulting product to a condensation reaction in the presence of a condensation accelerator that includes a compound of at least one element among the elements of the groups 4A (excluding Ti), 2B, 3B, and 5B of the periodic table.

Abstract: The invention provides a process for producing a modified conjugated diene based polymer which attains favorable interaction between a rubber component and carbon black and/or silica, thereby improving dispersibility of the fillers, and which exhibits excellent properties such as heat-buildup-suppressing performance, fracture characteristics, and wear resistance; a modified conjugated diene based polymer produced through the process; a rubber composition containing the diene polymer; and a tire produced from the rubber composition and exhibiting the above properties.

Abstract: A functionalized polymer prepared by a process comprising the steps of preparing a pseudo-living polymer by polymerizing conjugated monomer with a lanthanide-based catalyst, and reacting the pseudo-living polymer with a functionalizing agent defined by the formula (I) A-R1-Z??(I) where R1 is a divalent bond or divalent organic group comprising from 0 to about 20 carbon atoms, A is a substituent that will undergo an addition reaction with a pseudo-living polymer, and Z is a substituent that will react or interact with silica or carbon black reinforcing fillers, with the proviso that A, R1, and Z are substituents that will not protonate a pseudo-living polymer.

Abstract: A process for simply and inexpensively producing a conjugated diene polymer with a narrow molecular weight distribution and a high cis-bond content at a low cost is provided. The process comprises a polymerization step, wherein a conjugated diene polymer having a cis-1,4-bond content of 98.5 mass % or more and a ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) measured by gel permeation chromatography of 2.5 or less is obtained by carrying out a polymerization reaction in conjugated diene compounds using a catalyst composition containing a rare earth element-containing compound or a reaction product of the rare earth element-containing compound with a Lewis base, an aluminoxane and/or organoaluminum compound, and an iodine-containing compound.

Abstract: The present invention provides an emulsion composition which has been increased in sulfonic group content, yet has sufficient water resistance and has been enhanced in properties such as small resistance, film-forming property, etc. The emulsion composition contains (A) a water-based solvent, (B) an organic solvent, (C) a sulfonic group-containing polymer soluble in the component (A), and (D) a polymer soluble in the component (B) but insoluble in water. This emulsion composition is enhanced in small resistance and yet has sufficient water resistance and film-forming property.

Abstract: A process for producing a modified polymer which increases low heat buildup and reinforcing capability of a rubber composition and which has excellent abrasion resistance, mechanical characteristics, and processability; a modified polymer obtained by the process; and a rubber composition using the modified polymer are provided. The process comprises a step of carrying out a modification reaction on the active end of a conjugated diene polymer having a vinyl content of below 10%, a cis-1,4 bond content of 75% or higher, and an active end, using an alkoxysilane compound, and a step of carrying out a condensation reaction in the presence of a condensation accelerator comprising a compound of an element belonging to at least one of the groups 4A (excluding Ti), 2B, 3B, and 5B of the periodic table.

Abstract: There is provided a method for producing a conjugated diolefin (co)polymer rubber excellent in processability, independently of the kind and combination of filling agent incorporated, excellent in a balance among wet-skid characteristics, low hysteresis loss, wear resistance and breaking strength, when vulcanization treatment is performed to form a vulcanized rubber, and useful as a material for a tread or a sidewall member of a tire for low fuel consumption, a large sized tire or a high performance tire.

Abstract: Conjugated diene polymers having good wear resistance, mechanical properties, storage stability, processability and a reduced cold flow are produced by polymerizing a conjugated diene compound with a catalyst of rare earth element compound, a compound containing at least one halogen atom, an aluminoxane, and an organoaluminum compound in an organic solvent and reacting the resulting polymer just after the polymerization with at least one compound selected from the group consisting of a halogenated organometallic compound, a halogenated metal compound, an organometallic compound, a heterocumulene compound, a hetero three-membered-ring containing compound, a halogenated isocyano compound, a carboxylic acid, an acid halide, an ester compound, a carbonic ester compound, an acid anhydride and a metal salt of a carboxylic acid as a modifying agent.

Abstract: Disclosed are a method for producing a modified conjugated diene polymer improved in quality stability, more enhanced in low heat buildup and reinforcing ability when used in a rubber composition, excellent in wear resistance, mechanical characteristics and processability, and improved in cold flow; and a rubber composition using the same. The method includes a step of modifying an active end of an active end-containing conjugated diene polymer having a cis-1,4-bond content of 75% or more with an alkoxysilane compound containing at least one functional group selected from the group consisting of (a) an epoxy group, (b) an isocyanate group and (c) a carboxyl group, and a step of adding a condensation accelerator to conduct condensation reaction of the alkoxysilane compound (residue) in an aqueous solution having a pH of 9 to 14 and a temperature of 85 to 180° C.

Abstract: A rubber composition containing a modified conjugated diene polymer.