Process for making low crystallinity polyolefins

Claim 1

A process for the production of high molecular weight polyolefins having a degree of crystallinity less than about 25%, which process comprises polymerizing at least one 1-olefin containing at least 3 carbon atoms or a mixture of at least one of said olefins with up to about 67 weight % of ethylene in an inert liquid hydrocarbon diluent at a temperature ranging from about 25° C. to about 90° C. in the presence of a catalytic amount of a catalyst system consisting essentially of (a) a hydrocarbon soluble transition metal component derived by contacting in an inert liquid hydrocarbon (1) a soluble, halide free magnesium-carboxylate having the general formula Mg(OOCR') 2 where each R' is alike or different and is derived from a carboxylic acid containing at least 2 carbon atoms with (2) a soluble salt of a transition metal selected from the group consisting of tetravalent titanium, zirconium and hafnium, and (b) an alkylaluminum halide activator having the general formula R n AlX 3-n where R is a 1 to 18 carbon alkyl group and n is a number from 1.5 to 2.5, the molar ratio of transition metal salt to magnesium carboxylate being 0.003 to 3, the molar ratio of alkylaluminum halide activator to transition metal salt being at least 1 and the molar ratio of alkylaluminum halide activator to magnesium carboxylate being greater than 2.5.