Patent ID: 6794326
Filing Date: 2004-09-21
Classification: C08F

Abstract:
A catalyst system for polymerisation of ethylene, said catalyst system comprising chromium oxide and a metallocene compound supported on a particulate, inorganic oxide support;wherein at least 50% of the chromium of said chromium oxide is in a bivalent oxidation state, and wherein said metallocene compound has the formula: Cp2ZrRâ€²Râ€³wherein each Cp, being equal or different, is an unsubstituted or substituted cyclopentadienyl compound, and Râ€² and Râ€³, independent of each other, are selected from the group consisting of alkyls having 1 to 6 carbon atoms, unsubstituted or substituted benzyl, and phenoxy substituted with alkyls having 1 to 6 carbon atoms, and Râ€² or Râ€³ may be a halide, andwherein said catalyst system produced by a process wherein reduction of chromium is performed at a temperature within the range from 300Â° C. to 500Â° C.