Patent ID: 7012121

Claim:
A process for the polymerization of ethylene in the gas phase which comprises contacting ethylene in a gas phase polymerization reactor with a polymerization catalyst under gas phase polymerization conditions, wherein said polymerization catalyst comprises: (a) a metal complex which corresponds to the formula: wherein Cp is an anionic, delocalized, π-bonded group that is bound to M, containing up 50 nonhydrogen atoms; M is a metal of Group 4 of the Periodic Table of the Elements in the +2 or +4 formal oxidation state; X is a C 4-30 conjugated diene represented by the formula: wherein R 1 and R 4 are each a benzyl radical or a substituted benzyl radical, a phenyl radical or a substituted phenyl radical and R 2 and R 3 are each independently a hydrogen, aromatic, substituted aromatic, fused aromatic, substituted fused aromatic, aliphatic, substituted aliphatic, heteroatom-containing aromatic, heteroatom-containing fused aromatic, or silyl radical; D is —O—, —S—, —NR—, or —PR—; and Z is SiR 2 , CR 2 , SiR 2 SiR 2 , CR 2 CR 2 , CR═CR, CR 2 SiR 2 , or GeR 2 , wherein R is in each occurrence independently selected from the group consisting of hydrogen, hydrocarbyl, silyl, germyl, cyano, halo and combinations thereof, said R having up to 20 nonhydrogen atoms, or adjacent R groups together form a hydrocarbadiyl, siladiyl or germadiyl group thereby forming a fused ring system; (b) a cocatalyst represented by the formula: [L*-H] +[(C 6 F 5 ) 3 BC 6 H 4 —O—AlR C x-1 X a y ] − , wherein L* is a neutral Lewis base, R c independently each occurrence is a hydrogen or a hydrocarbyl, hydrocarbylsilyl, or hydrocarbylsilylhydrocarbyl group having from 1 to 80 nonhydrogen atoms; X a is a halo-substituted hydrocarbyl, hydrocarbylamino-substituted hydrocarbyl, hydrocarbyloxy-substituted hydrocarbyl, hydrocarbylamino, di(hydrocarbyl)amino, hydrocarbyloxy or halide noninterfering group having from 1 to 100 nonhydrogen atoms; x is an integer which ranges from 1 to an integer equal to the valence of Al; y is an integer which ranges from 0 to an integer equal to 1 less than the valence of Al; and x+y equals the valence of Al; and (c) a support for the metal complex and the cocatalyst, wherein the polymerization catalyst, when injected into the gas phase polymerization reactor, and contacted with the ethylene, demonstrates a kinetic profile which obeys the following inequality: Kr =A 30 /A 90 ≦1.6 where Kr is the ratio of the cumulative net catalyst activity at 30 minutes after the onset of polymerization (A 30 ) divided by the cumulative net catalyst activity at 90 minutes after the onset of polymerization (A 90 ) and wherein A 30 and A 90 are determined by calculating the grams polymer/gram polymerization catalyst×time (hr)×total ethylene pressure (100 kPa).