Low pressure copolymerization of ethylene with .alpha.-olefins and ethylene copolymers having a low residual monomer content

US5071950A · kind A · utility

Assignee

• BASF SE

Inventors

• Klaus Borho · Mutterstadt, DE
• Horst Bullack · Wesseling, DE
• Alfred F. Hauss
• Peter Hennenberger · Freinsheim, DE
• Klaus Hilligardt · Schifferstadt, DE
• Benno Knauer · Ludwigshafen, DE
• Farid Rizk · Schifferstadt, DE
• Heinz Vogt · Ludwigshafen, DE

Key dates

• Filing date: Sep 24, 1990
• Grant date: Dec 10, 1991
• Expiry date: Sep 24, 2010

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08F6/006
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Ethylene/.alpha.-olefin copolymers are prepared by catalytic dry-phase copolymerization of the monomers in a stirred or fluidized polymerization zone, transfer of the resulting mixture of solid copolymer and unconverted gaseous monomer into a let-down zone and separation of the mixture, after pressure reduction, into a gaseous phase and a solid phase, by a continuous process in which the solid phase is continuously flushed beforehand with gaseous ethylene and then flushed with a mixture of nitrogen and steam. The ethylene copolymers are very substantially free of residual monomers and odor and flavor substances.