Catalyst composition and process for polymerizing olefins.

摘要

An improved process for producing an olefin polymer or copolymer by using a novel catalyst composition composed of (A) a titanium catalyst component containing magnesium, titanium, halogen and an ester specified in Claim 1, as an electron donor, (B) an organoaluminum compound and (C) a heterocyclic compound or a ketone specified in Claim 1, as a third component. The combination parameter of the ester in (A) and the (C) component is new, and the process can give a highly stereospecific olefin polymer or copolymer in high yields.