Patent ID: 6114477
Filing Date: 2000-09-05
Classification: C08F,Y10S

Abstract:
A continuous gas phase process for polymerizing olefins in the presence of a catalyst system consisting essentially of one or more unbridged metallocene catalysts to form a polyolefin product having an activation energy of viscous flow (E.sub.a) greater than or equal to 7.6 kcal/mole, the process comprising a) introducing to a reactor ethylene; and, optionally, one or more comonomers; b) cycling said ethylene and optional comonomers through a fluidized bed containing said catalyst system on support material, c) employing a continuous recycle stream containing said ethylene and optional comonomers; d) withdrawing a polyethylene product; and e) replacing the withdrawn polyethylene product and consumed catalyst with new said ethylene and optional comonomers and new said catalyst system; said process conducted such that the ethylene partial pressure is from about 40 psi to about 150 psi and the reactor temperature is in the range of 85 to 110.degree. C.;whereby reduction of partial pressure of said ethylene and varying the reactor temperature, results in said activation energy being greater than or equal to 7.6 kcal/mole.