| abstract |
(57) [Problem] To provide good workability in any combination of carbon black blending and silica blending, and simultaneously improve wear resistance, fracture properties, low hysteresis loss properties, and wet skid properties. Provided is a conjugated diolefin-based copolymer rubber that can be used as a tread material for fuel-efficient tires, large tires, and high-performance tires. (1) A copolymer of a conjugated diolefin and an aromatic vinyl compound, and (2) a copolymer rubber having an amino group content of 0.0025 to 0.20 mmol / g. (3) the content of the polymerized unit of the aromatic vinyl compound is 5% by weight or more and less than 30% by weight, and the vinyl bond content (1,2 bond, 3,4 bond content) in the polymerized unit of the conjugated diolefin portion; Is not less than 55 mol% or the content of polymerized units of the aromatic vinyl compound is 3 0 to 50% by weight and the vinyl bond content in the polymerized unit of the conjugated diolefin moiety is 25 to 55 mol%, and (4) the molecular weight distribution measured by GPC is of a polymodal type. Conjugated diolefin-based copolymer rubber. |