| abstract |
PROBLEM TO BE SOLVED: To provide a copolymer comprising a conjugated diolefin and an aromatic vinyl compound which is particularly suitable for the production of a tire and a method for producing the copolymer. A method of copolymerizing a conjugated diolefin and a vinyl-aromatic compound, wherein the polymerization of the conjugated diolefin and the vinyl-aromatic compound is performed, for example, by (a) In the presence of a catalyst comprising at least one rare earth metal compound, (b) at least one organoaluminum compound, and an inert aliphatic and / or aromatic solvent or mixtures thereof, at a temperature of from −30 to 140 ° C. ): The molar ratio of (b) is 1: (0.1 to 1000), and the catalyst of the component (a) is used in an amount of 1 μmol to 1 with respect to 100 g of the conjugated diolefin used. 0 to 2000 mmol per 100 g of conjugated diolefin using a vinyl-aromatic compound. Use in the amount of g. |