Patent ID: 7045578
Filing Date: 2006-05-16
Classification: B60C,C08C,C08F,C08K,C08L

Abstract:
1. An oil-extended rubber comprising a conjugated diene rubber comprising 30 to 99.9% by weight of 1,3-butadiene units, 0.1 to 10% by weight of isoprene units and 0 to 60% by weight of aromatic vinyl monomer units, and an extender oil; characterized in that the conjugated diene rubber is obtained by a process wherein a monomer mixture comprising at least 80% by weight of 1,3-butadiene based on the total amount of 1,3-butadiene used for polymerization, not larger than 80% by weight of isoprene based on the total amount of isoprene used for polymerization, and at least 80% by weight of an aromatic vinyl monomer based on the total amount of the aromatic vinyl monomer used for polymerization is polymerized by using an organic active metal as an initiator in a hydrocarbon medium; the remainder of isoprene is added to continue polymerization to form a chain portion consisting of isoprene units, then; the remainder of 1,3-butadiene and the remainder of aromatic vinyl monomer are added thereto to continue polymerization; and then, the resulting living polymer having an activated terminal is reacted with a coupling agent.