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 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: A hydrogenated conjugated diene-based polymer of the present invention has a branch number (Bn) measured by viscosity detector-equipped GPC-light scattering measurement of 2.5 or more, and a hydrogenation rate of a structural unit derived from a conjugated diene compound of 30% or more and less than 99%.

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 conjugated diene-based polymer of the present invention has an absolute molecular weight measured by viscosity detector-equipped GPC-light scattering measurement, of 40×104 or more and 5000×104 or less, has a branching number (Bn) measured by the viscosity detector-equipped GPC-light scattering measurement, of 8 or more, and has a modification ratio of 60% by mass or more.

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 modified conjugated diene-based polymer having a nitrogen atom, wherein a content of the nitrogen atom is 25 mass ppm or more based on a total amount of the modified conjugated diene-based polymer, a shrinking factor (g?) is 0.59 or less in a GPC-light scattering measurement method with a viscosity detector, and a weight average molecular weight is 200,000 or more and 3,000,000 or less.

Abstract: A conjugated diene-based polymer of the present invention has an absolute molecular weight measured by viscosity detector-equipped GPC-light scattering measurement, of 40×104 or more and 5000×104 or less, has a branching number (Bn) measured by the viscosity detector-equipped GPC-light scattering measurement, of 8 or more, and has a modification ratio of 60% by mass 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, wherein the Mooney stress-relaxation rate measured at 110° C. is 0.45 or less, and the modification percentage is 75% by mass or more.

Abstract: A modified conjugated diene-based polymer having a nitrogen atom, wherein a content of the nitrogen atom is 25 mass ppm or more based on a total amount of the modified conjugated diene-based polymer, a shrinking factor (g?) is 0.59 or less in a GPC-light scattering measurement method with a viscosity detector, and a weight average molecular weight is 200,000 or more and 3,000,000 or less.

Abstract: The present invention provides a modified conjugated diene-based polymer, wherein the Mooney stress-relaxation rate measured at 110° C. is 0.45 or less, and the modification percentage is 75% by mass or more.