A PROCESS FOR PREPARING A HYDROGEN SENSITIVE alpha -OLEFIN POLYMERIZATION CATALYST SYSTEM, A POLYMERIZATION CATALYST SYSTEM PREPARED BY THE PROCESS AND ITS USE FOR THE POLYMERIZATION OF alpha -OLEFINS

摘要

In the invention, improved isotacticity and melt processability of poly- alpha -olefins have been achieved by means of a novel polymerization and a catalyst system therefor. The catalyst system has been prepared by a process in which magnesium dichloride or a complex thereof, titanium tetrachloride, and internal donor, a first organoaluminium compound, and an external donor are contacted to form a contacting product. The contacting product is then contacted with a second organoaluminium compound which, on an atom basis, contains more halogen per aluminium than the first organoaluminium compound.