Catalyst composition comprising shuttling agent for tactic/ atactic multi-block copolymer formation

摘要

Copolymers, especially multi-block copolymer containing therein two or more segments or blocks differing in tacticity, are prepared by polymerizing propylene, 4-methyl-1-pentene, or another C4-8 α-olefin in the presence of a composition comprising the admixture or reaction product resulting from combining:
(A) a first metal complex olefin polymerization catalyst,(B) a second metal complex olefin polymerization catalyst capable of preparing polymers differing in tacticity from the polymer prepared by catalyst (A) under equivalent polymerization conditions, and(C) a chain shuttling agent.

主权项

1. A process for preparing a propylene containing multi-block copolymer comprising contacting propylene under addition polymerization conditions with a composition comprising:
the admixture or reaction product resulting from combining: (A) a first olefin polymerization catalyst, (B) a second olefin polymerization catalyst capable of preparing a polymer differing in tacticity from the polymer prepared by catalyst (A) under equivalent polymerization conditions, and (C) a chain shuttling agent, wherein the molecular weight distribution, Mw/Mn, of the copolymer is 1.7 to 2.9 and the shuttling agent is a dihydrocarbyl zinc-compound containing from 1 to 12 carbons in each hydrocarbyl group.