THE INDUSTRIAL SYNTHESIS OF BIMODAL POLYETHYLENE GRADES WITH IMPROVED PROPERTIES

It is well-known for a long time that polyethylenes with broad, bimodal molecular mass distributions have improved properties in respect to processibility, impact properties, and stress crack resistance. Polyethylenes with very broad bimodal molecular mass distributions can be synthesized using new high-mileage catalysts with excellent behaviour in average molecular mass regulation by hydrogen and copolymerization with 1-olefines. The appropriate technology is the cascade process. It is possible to generate reactor blends which form a polymer alloy in the solid state. Such materials have properties so far unknown. New types of engineering polyethylene materials are accessible by progress in catalyst development and polymerization technology in combination with a basic understanding of structure properties relations of the polymer in the solid state.