Patent ID: 6960634
Filing Date: 2005-11-01
Classification: C08F

Abstract:
1. A method of controlling the Melt Index Ratio of a polyolefin from about 30 to about 150, the method comprising contacting ethylene and one or more olefin comonomers having 3 to 12 carbon atoms under polymerization conditions with a catalyst system comprising an activator and a metallocene catalyst precursor compound; the metallocene catalyst precursor compound comprising a Group 4 transition metal atom bound to two cyclopentadienyl ligands, wherein the two cyclopentadienyl ligands are bridged to each other through a bridging group represented by the formula -A′R 1 R 2 — wherein A′ is selected from Si and Ge, and R 1 and R 2 are independently selected from C 1 -C 20 hydrocarbyl groups; and wherein the two bridged ligands have a total number of substituents in the range of from 3 to 8 C 1 -C 2 alkyl substituents; and isolating the polyolefin; characterized in that the Melt Index Ratio of the polyolefin produced by the catalyst system is increased by decreasing the total number of said C 1 to C 2 alkyl substituents on the metallocene catalyst precursor compound for polyolefins having a density of from about 0.915 to about 0.930 g/cc.