Patent ID: 7863385

Claim:
A method for producing vinylâ€¢cis-polybutadiene rubber by a step of cis-1,4 polymerization of 1,3-butadiene using a cis-1,4 polymerization catalyst in a hydrocarbon-series solvent to obtain a first polymerization mixture, a step of 1,2 polymerization of 1,3-butadiene in the concurrent presence of a 1,2 polymerization catalyst in the first polymerization mixture to generate a second polymerization mixture including 1,2-polybutadiene having a melting point of 170Â° C. or more, and a step of separation and recovery of vinylâ€¢cis-polybutadiene rubber generated from the second polymerization mixture, the method further including a step of adding a polymer substance with at least one unsaturated double bond per repeating unit to the production system of vinylâ€¢cis-polybutadiene rubber, wherein the polymer substance comprises at least one selected from the group consisting of polyisoprene, crystallizable polybutadiene having a melting point less than 170Â° C., liquid polybutadiene, a polymeric compound containing an ether group, an epoxy group, a carboxyl group, an ester group, a hydroxyl group, or a carbonyl group, and derivatives of the polymer substance thereof.