US Patent 7273912 Supported olefin polymerization catalyst

Supported catalyst systems are provided comprising (a) a transition metal compound, (b) a non aluminoxane activator comprising, and (c) a support material comprising an inorganic metal oxide, inorganic metal halide or polymeric material or mixtures thereof characterised in that the support material has been pretreated with an SO4 containing compound. The preferred transition metal compounds are metallocenes and the SO4 containing compound is typically sulphuric acid. The supported catalyst systems show improved activity and also may reduce fouling in gas phase fluidised bed processes.