Crystalline polyolefins and production thereof

摘要

Crystalline polyolefins of high molecular weight and high crystallinity are produced in high yields by polymerizing an olefin in the presence of a catalytic system comprising a combination of an organoaluminum compound and a modified titanium composition which has been prepared by milling together a halogen compound of titanium of a valence lower than the maximum valence (e.g. titanium trichloride) and an alpha , beta -unsaturated carboxylate ester.