Abstract: A production method for a branched conjugated diene-based polymer, comprising: a polymerizing step of obtaining a conjugated diene-based polymer having an active end by polymerizing or copolymerizing a conjugated diene compound, or a conjugated diene compound and an aromatic vinyl compound with an alkali metal compound or an alkaline earth metal compound used as a polymerization initiator; and a branching step of introducing a branch structure by reacting a styrene derivative as a branching agent with the active end of the conjugated diene-based polymer.

Abstract: The present invention provides a molded bale of a rubber-like block copolymer, satisfying the following requirements 1 to 6: Requirement 1: a content of a vinyl aromatic monomer unit is 9% by mass or more and 50% by mass or less; Requirement 2: a proportion of a vinyl aromatic monomer block is 3% by mass or more and less than 30% by mass; Requirement 3: an iodine value is 3 to 250; Requirement 4: a proportion of an ethylene structure is 3% by mass or more; Requirement 5: a weight average molecular weight is in a range of 80,000 to 1,000,000; and Requirement 6: at least one block at a molecular end is a specific block I or block II.

Abstract: The present invention provides a conjugated diene-based polymer excellent in processability in vulcanization, and excellent in abrasion resistance and a low hysteresis loss property of a vulcanizate obtained therefrom. The present invention relates to a conjugated diene-based polymer, having a branch number measured by viscosity detector-equipped GPC-light scattering measurement of 7 or more, an amount of bound aromatic vinyl of 1% by mass or more and 32% by mass or less, and a content of vinyl bond in bound conjugated diene of 11% by mol or more and 35% by mol or less.

Abstract: The conjugated diene-based polymer has a Mooney viscosity measured at 100° C. of 40 or more and 170 or less, has Mooney stress relaxation measured at 100° C. of 0.35 or less, and has a branch number (Bn) measured by viscosity detector-equipped GPC-light scattering measurement of 8 or more.

Abstract: A conjugated diene-based polymer of the present invention has a branch number (Bn) measured by viscosity detector-equipped GPC-light scattering measurement of 8 or more, has a change (?T) of an oxidation onset temperature caused through application of a thermal load of 11.9° C. or less, and contains an aromatic vinyl compound monomer unit.

Abstract: A modified conjugated diene-based polymer, including a coupling polymer, wherein a ratio of the coupling polymer, obtained by gel permeation chromatography (GPC), is 30% by mass or more and less than 70% by mass in the entire modified conjugated diene-based polymer, and a modification ratio obtained by adsorption GPC is 30% by mass or more and less than 70% by mass in the entire modified conjugated diene-based polymer, when a peak top molecular weight, obtained by the GPC, of the coupling polymer of the modified conjugated diene-based polymer is represented by Mp1 and a peak top molecular weight of a non-coupling polymer is represented by Mp2, (Mp1/Mp2)?3.4, and a shrinking factor (g?) is less than 0.60.

Abstract: A modified conjugated diene-based polymer containing: having a weight average molecular weight of 20×104 or more and 300×104 or less, having a star-branched structure with a conjugated diene-based polymer chain bonded to a modifier residue, wherein the modifier residue has at least 4 silicon atoms, and alkoxy groups and/or hydroxyl groups and the conjugated diene-based polymer chain is bonded to the silicon atom, wherein the number of alkoxy groups and/or hydroxyl groups in the modifier residue is larger than the number of the silicon atoms on average.

Abstract: A modified conjugated diene-based polymer, including a coupling polymer, wherein a ratio of the coupling polymer, obtained by gel permeation chromatography (GPC), is 30% by mass or more and less than 70% by mass in the entire modified conjugated diene-based polymer, and a modification ratio obtained by adsorption GPC is 30% by mass or more and less than 70% by mass in the entire modified conjugated diene-based polymer, when a peak top molecular weight, obtained by the GPC, of the coupling polymer of the modified conjugated diene-based polymer is represented by Mp1 and a peak top molecular weight of a non-coupling polymer is represented by Mp2, (Mp1/Mp2)?3.4, and a shrinking factor (g?) is less than 0.60.

Abstract: Problem to be Solved The present invention provides a conjugated diene-based polymer composition excellent in rolling resistance, grip performance on a wet road surface, and abrasion resistance when formed into a tire. Solution A conjugated diene-based polymer composition containing: 10 to 90 parts by mass of a conjugated diene-based polymer (A) having a glass transition temperature of ?20° C. or more; and 10 to 90 parts by mass of a conjugated diene-based polymer (B) having a glass transition temperature of ?25° C. or less, wherein the conjugated diene-based polymer (A) has an absolute molecular weight, measured by viscosity detector-equipped GPC-light scattering measurement, of 40×104 or more and 5000×104 or less, and a branch number (Bn), measured by the viscosity detector-equipped GPC-light scattering measurement, of 8 or more.

Abstract: A production method for a branched conjugated diene-based polymer, comprising: a polymerizing step of obtaining a conjugated diene-based polymer having an active end by polymerizing or copolymerizing a conjugated diene compound, or a conjugated diene compound and an aromatic vinyl compound with an alkali metal compound or an alkaline earth metal compound used as a polymerization initiator; and a branching step of introducing a branch structure by reacting a styrene derivative as a branching agent with the active end of the conjugated diene-based polymer.

Abstract: The present invention provides a modified conjugated diene-based polymer having a weight-average molecular weight of 20×104 or more and 300×104 or less, in which the modified conjugated diene-based polymer having a molecular weight of 200×104 or more and 500×104 or less is comprised in an amount of 0.25% by mass or more and 30% by mass or less based on a total amount of the modified conjugated diene-based polymer, and a shrinking factor (g?) is less than 0.64.

Abstract: In a modified conjugated diene-based polymer, a ratio of a coupling polymer, obtained by gel permeation chromatography (GPC), is 70% by mass or more based on a total amount of the modified conjugated diene-based polymer, and a modification ratio obtained by adsorption GPC is 70% by mass or more based on a total amount of the modified conjugated diene-based polymer, and when Mooney viscosity ML1+4 (100° C.) measured at 100° C. is represented by ML and a weight average molecular weight obtained by GPC is represented by Mw, ML?1.8 (Mw×10?4)?31.5, and Mooney viscosity ML1+4 (100° C.) measured at 100° C. is 30 to 150.

Abstract: A modified conjugated diene-based polymer containing: having a weight average molecular weight of 20×104 or more and 300×104 or less, having a star-branched structure with a conjugated diene-based polymer chain bonded to a modifier residue, wherein the modifier residue has at least 4 silicon atoms, and alkoxy groups and/or hydroxyl groups and the conjugated diene-based polymer chain is bonded to the silicon atom, wherein the number of alkoxy groups and/or hydroxyl groups in the modifier residue is larger than the number of the silicon atoms on average.

Abstract: In a modified conjugated diene-based polymer, a ratio of a coupling polymer, obtained by gel permeation chromatography (GPC), is 70% by mass or more based on a total amount of the modified conjugated diene-based polymer, and a modification ratio obtained by adsorption GPC is 70% by mass or more based on a total amount of the modified conjugated diene-based polymer, and when Mooney viscosity ML1+4 (100° C.) measured at 100° C. is represented by ML and a weight average molecular weight obtained by GPC is represented by Mw, ML 1.8 (Mw×10?4)?31.5, and Mooney viscosity ML1+4 (100° C.) measured at 100° C. is 30 to 150.

Abstract: The present invention provides a modified conjugated diene-based polymer having a weight-average molecular weight of 20×104 or more and 300×104 or less, in which the modified conjugated diene-based polymer having a molecular weight of 200×104 or more and 500×104 or less is comprised in an amount of 0.25% by mass or more and 30% by mass or less based on a total amount of the modified conjugated diene-based polymer, and a shrinking factor (g?) is less than 0.64.

Abstract: A method for producing a modified conjugated diene-based polymer having a good balance between the hysteresis loss properties and the wet skid resistance, practically sufficient abrasion resistance and breaking strength, and high processability when formed into a vulcanized product is provided. A method for producing a modified conjugated diene-based polymer, comprising: a polymerization step of polymerizing a conjugated diene compound, copolymerizing conjugated diene compounds, or copolymerizing a conjugated diene compound with an aromatic vinyl compound using an alkali metal compound or an alkaline earth metal compound as a polymerization initiator to obtain a conjugated diene-based polymer having an active end, and a modifying step of reacting a compound represented by following formula (1) with the active end of the conjugated diene-based copolymer.

Abstract: A method for producing a modified conjugated diene-based polymer having a good balance between the hysteresis loss properties and the wet skid resistance, practically sufficient abrasion resistance and breaking strength, and high processability when formed into a vulcanized product is provided. A method for producing a modified conjugated diene-based polymer, comprising: a polymerization step of polymerizing a conjugated diene compound, copolymerizing conjugated diene compounds, or copolymerizing a conjugated diene compound with an aromatic vinyl compound using an alkali metal compound or an alkaline earth metal compound as a polymerization initiator to obtain a conjugated diene-based polymer having an active end, and a modifying step of reacting a compound represented by following formula (1) with the active end of the conjugated diene-based copolymer.

Abstract: A method for producing a modified conjugated diene-based polymer having a good balance between the hysteresis loss properties and the wet skid resistance, practically sufficient abrasion resistance and breaking strength, and high processability when formed into a vulcanized product is provided. A method for producing a modified conjugated diene-based polymer, comprising: a polymerization step of polymerizing a conjugated diene compound, copolymerizing conjugated diene compounds, or copolymerizing a conjugated diene compound with an aromatic vinyl compound using an alkali metal compound or an alkaline earth metal compound as a polymerization initiator to obtain a conjugated diene-based polymer having an active end, and a modifying step of reacting a compound represented by following formula (1) with the active end of the conjugated diene-based copolymer.

Abstract: There is provided a modified conjugated diene-based polymer having a silyl group substituted with one or more alkoxy groups, and one or more nitrogen atoms on the chain ends of a conjugated diene-based polymer, the modified conjugated diene-based polymer being obtained by polymerizing a conjugated diene compound, or copolymerizing a conjugated diene compound with an aromatic vinyl compound, by using a polyfunctional anionic polymerization initiator prepared from a polyvinyl aromatic compound and an organolithium compound in a range of a molar ratio (the polyvinyl aromatic compound/the organolithium compound) of from 0.05 to 1.0, so as to obtain the conjugated diene-based polymer, and by reacting a living polymer end of the conjugated diene polymer with the compound having a silyl group substituted with two or more alkoxy groups, and one or more nitrogen atoms.

Abstract: There are provided a modified conjugated diene-based polymer having a good balance between the hysteresis loss properties and the wet skid resistance, practically sufficient abrasion resistance and fracture strength, and high processability when formed into a vulcanized product, and a modified conjugated diene-based polymer composition. A method for producing a modified conjugated diene-based polymer, comprising: a polymerization step of polymerizing a conjugated diene compound or copolymerizing a conjugated diene compound with an aromatic vinyl compound using an alkali metal compound or an alkaline earth metal compound as a polymerization initiator to obtain a conjugated diene-based polymer having a reactive end, and a modifying step of reacting a compound having a specific structure with the reactive end of the conjugated diene-based polymer.