Ziegler type catalyst composition.

摘要

A catalyst system for alpha-olefin type polymerizations which comprises at least one metal alkyl compound having the formula R3'''M in combination with a titanium metal compound on a support, at least one hindered Lewis base and a sterically hindered salt of A group I A to group III B metal wherein R''' is C1 to C20 primary, secondary of tertiary alkyl, cycloalkyl, alkenyl or aralkyl groups or hydrogen and M is aluminium, gallium or indium. The improved catalyst system provides polymers having increased isotactic stereoregularity as well as lower catalyst residue.