Patent ID: 7420021
Filing Date: 2008-09-02
Classification: C08F

Abstract:
1. A catalyst composition for the polymerization of propylene or mixtures of propylene and one or more copolymerizable comonomers, said catalyst composition comprising one or more Ziegler-Natta procatalyst compositions comprising: one or more transition metal compounds and one or more monoesters of aromatic carboxylic acid internal electron donors; one or more aluminum containing cocatalyst; and a mixture of two or more different selectivity control agents (SCA), said SCA mixture comprising from 98.5 to 99.9 mol percent of one or more esters of one or more aromatic monocarboxylic acids or substituted derivatives thereof, and from 1.5 to 0.1 mol percent of one or more alkoxysilane compounds.