Patent ID: 7247695

Claim:
A method for preparing a high 1,4-cis polybutadiene-polyurethane copolymer represented by the following formula 1: wherein l, m, n and o represent the number of repeating unit, l is 94 to 99%, m is 0 to 5%, n is 0 to 5%, l+m+n=100%, l/(m+n) is 15 to 100, o is 1 to 100%; and A and Y are C 1 -C 20 alkyl or aryl, the method comprising; (a) polymerizing 1,3-butadiene or butadiene derivatives with a catalyst comprising a rare earth compound, a halogen-containing compound and an organoaluminum compound in the presence of a non-polar solvent, to prepare polybutadiene having a high 1,4-cis content of at least 95% except monohydroxy-terminated polybutadiene; and (b) adding an isocyanate compound having at least two functional groups and an alcohol compound having at least two functional groups with or without base or tin catalyst to the result of the step (a).