| abstract |
A new improved catalyst system for polymeric polymerizations, includes at least one metal alkyl compound having the formula RnMR'3-n in combination with a Group IVB-VIII transition metal compound on a support and at least one Lewis base wherein R is selected from the group consisting of C3 to C20 secondary or tertiary alkyl, cycloalkyl, alkenyl or aralkyl groups, or <IMAGE> wherein R'' is a methyl or ethyl group and R''' is a C1 to C10 alkyl group; R' is selected from the group consisting of C1 to C20 primary alkyl, alkenyl or aralkyl groups, or a hydride, M is selected from the group consisting of aluminum, gallium, or indium; and n = 1-3. The improved catalyst system provides polymers having increased isotactic stereoregularity as well as lower catalyst residue. |