Patent ID: 7619049

Claim:
A catalyst system for the polymerization or co-polymerization of alpha-olefin comprising a solid Ziegler-Natta type catalyst component, a co-catalyst component, and an electron donor component comprising at least one cyclic organosilicon compound of the formula: wherein Q 1 and Q 2 are each a hetero-atom independently selected from the group consisting of N, O, S, Si, B, P, with the proviso that Q 1 and Q 2 cannot both be N or both be O; wherein R 1 and R 2 are independently each a hydrocarbon-based substituent to Q 1 and Q 2 , respectively; wherein m and n are independently 0-3; wherein R 3 is an aliphatic, alicyclic or aromatic group; wherein R 4 is a hydrocarbon group with 1 to 6 carbon atoms; and wherein R 5 is a bridging group with a backbone chain length between the two hetero-atoms Q 1 and Q 2 being 1-8 atoms, wherein the backbone of said bridging group is selected from the group consisting of aliphatic, alicyclic, and aromatic radicals.