Patent ID: 6489411
Filing Date: 2002-12-03
Classification: C08F

Abstract:
In a method for the polymerization of an olefin with a Ziegler catalyst system, the method comprising;(a) providing a first composite Ziegler catalyst system comprising a transition metal catalyst component comprising a group 4, 5 or 6 transition metal and having an internal electron donor present in an amount to provide an internal donor/transition metal mole ratio of no more than 2/3, an organoaluminum co-catalyst component in an amount to provide an aluminum/transition metal mole ratio of at least 100 and an organosilicon electron donor component present in an amount to provide an aluminum/silicon mole ratio of no more than 200. (b) supplying said catalyst system to a polymerization reactor containing an olefin to effect polymerization of said olefin with said first catalyst system; (c) providing a second composite Ziegler catalyst system comprising a transition metal catalyst component comprising a group 4, 5 or 6 transition metal and having an internal electron donor present in an amount to provide an internal donor/transition metal mole ratio of no more than 2/3, but having a different internal electron donor/transition metal mole ratio than said first system, an organoaluminum co-catalyst component in an amount to provide an aluminum/transition metal mole ratio of at least 100 and an organosilicon electron donor component present in an amount to provide an aluminum/silicon mole ratio of no more than 200; and (d) and introducing said second catalyst system into said polymerization reactor to effect polymerization of said olefin with said second catalyst system to achieve a different polymerization characteristic than said first catalyst system.