Progress in Bimodal Polyethylene Produced by Metallocene Catalyst

摘要

The external new ways, kinds and recant advances of bimodal Polyethylene produced by metallocene catalyst were reviewed. For example, U.S.Pat.No 4939217 discloses an olefin polymerization supported catalyst comprising at least two different metallocenes each having different olefin polymerization termination rate constants in the presence of hydrogen. U.S.Pat. No.5077255 discloses an olefin polymerization supported catalyst comprising at least one metallocene of a metal, a non-metallocene transition metal and an alumoxane. The supported product is highly useful for the polymerization of olefins especially ethylene and especially for the copolymerization of ethylene and other mono and diolefins. U.S.Pat.No.5986024 discloses a process is provided for preparing polymer compositions which are multimodal in nature. The process involves contacting, under polymerization conditions, a selected addition polymerizable monomer with a metallocene catalyst having two or more distinct and chemically different active sites, and a catalyst activator.　　……