Patent ID: 7432336

Claim:
A process for preparing a propylene copolymer, said process comprising: polymerizing propylene and ethylene in the presence of the product of an activator and a metallocene compound represented by the formula: wherein: M is hafnium R 1 are identical or different, and are one of a hydrogen atom, a C 1 -C 10 alkyl group, a C 1 -C 10 alkoxy group, a C 6 -C 10 aryl group, a C 6 -C 10 aryloxy group, a C 2 -C 10 alkenyl group, a C 7 -C 40 arylalkyl group, a C 7 -C 40 alkylaryl group, a C 8 -C 40 arylalkenyl group, a halogen atom, or a conjugated diene, said conjugated diene substituted with one or more hydrocarbyl, tri(hydrocarbyl)silyl or tri(hydrocarbyl)silylhydrocarbyl groups, and said diene having up to 30 atoms not counting hydrogen; R 2 is a hydrogen atom; R 3 is a hydrogen atom; R 8 is wherein: R 14 , R 15 and R 16 are identical or different, and are a hydrogen, a halogen, a C 1 -C 20 branched or linear alkyl group, a C 1 -C 20 fluoroalkyl, a silylalkyl group, a C 6 -C 30 aryl group, a C 6 -C 30 fluoroaryl group, a C 1 -C 20 alkoxy group, a C 2 -C 20 alkenyl group, a C 7 -C 40 arylalkyl group, a C 8 -C 40 arylalkenyl group, a C 7 -C 40 alkylaryl group, or R 14 and R 15 , together with the atoms binding them, form a cyclic ring; M 2 is carbon; R 9 and R 10 are identical or different, and have the meanings stated for R 1 ; R 4 , R 5 , R 6 and R 7 are identical or different, and have the meanings stated for R 1 provided that at least one of R 4 and R 7 is not hydrogen; and m and n are identical or different, and are zero, 1 or 2; wherein the propylene copolymer comprises: a) at least 50 wt % units derived from propylene; b) from 10 wt % to 20 wt % ethylene derived units, based on the total weight of the copolymer; and c) a ratio of g′ as determined by the formula: ( g′ 88-98 )/( g′ 20-60 )≧1.20 where the subscripts, 88-98 and 20-60, refer to the wt % of copolymer eluted in GPC-DRI, and in the numerator and the denominator, g′ is the weight average g′ over the elution range designated 88-98 and 20-60, respectively, and d) a weight average molecular weight of 20,000 to 1,000,000 g/mol.