Process for the production of cycloolefin-based random copolymer

摘要

A process for the production of a cycloolefin-based random copolymer, which comprises: (A) copolymerizing (a) ethylene and (b) at least one cycloolefin, (B) in the presence of a catalyst comprising a vanadium compound soluble in a mixed solvent described below and an organoaluminum compound. (C) in a mixed solvent comprising (a) a hydrocarbon-based solvent having a solubility parameter ( delta value) of not less than 7.7 (cal/cm3)1/2 and (b) a hydrocarbon-based solvent having a solubility parameter ( delta value) of not more than 7.5 (cal/cm3)1/2, the mixed solvent having a volume ratio (a)/(b) of 90/10 to 50/50. The said process permits the production of a copolymer in a higher concentration when copolymers having an identical molecular weight to that of conventional copolymers are produced, and permits the production of a copolymer having a higher molecular weight when copolymers are produced in an identical concentration to that of conventional copolymers.