Hydrocarbon-soluble copolymers of bicycloheptenes and 1,3-butadiene

Claim 1

A process for preparing substantially gel-free hydrocarbon-soluble copolymers of a bicycloheptene and 1,3-butadiene whereby bicycloheptene is selected from monomers defined by Formula I as follows: ##STR3## wherein each X and Y is hydrogen or an alkyl or alkenyl group containing from one to 20 carbon atoms, or the two Y groups jointly represent the group --CH═CH--CH 2 -- thereby forming an additional ring, and Formula II as follows: ##STR4## wherein X is hydrogen or an alkyl group containing one to 20 carbon atoms, or mixtures of said bicycloheptenes, said process comprising polymerizing a monomer mixture of at least one bicycloheptene and from about 0.01% to about 95% by weight, based upon the total polymer weight, of 1,3-butadiene in a hydrocarbon solvent in the presence of a catalyst mixture consisting essentially of (a) at least one organoaluminum compound of the formula R 3 Al or R 2 AlX wherein R is an alkyl group containing from 1 to about 12 carbon atoms, and X is a halogen, and (b) at least one molybdenum salt.