| abstract |
A catalyst system for alphaolefin type polymerizations, including at least one metal alkyl compound having the formula R"' 3 Min combination with a Group IVA-VIII transition metal chloride or bromide on a support and a hindered and an unhindered Lewis base wherein R"' is C 1 to C 20 primary, branched primary, secondary or tertiary alkyl, cycloalkyl, alkenyl or aralkyl group, or a hydride, M is aluminium, gallium or indium. The improved catalyst system provides polymers having increased isotactic stereoregularity as well as lower catalyst residue. |