Preparation of propylene/ethylene block copolymers

US4455405A · kind A · utility

Assignee

• BASF SE

Inventors

• James F. R. Jaggard · Ludwigshafen, DE
• Guenther Schweier · Friedelsheim, DE
• Peter Klaerner · Battenberg, DE

Key dates

• Filing date: Nov 1, 1982
• Grant date: Jun 19, 1984
• Expiry date: Nov 1, 2002

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08F297/083
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Propylene/ethylene block copolymers are prepared by a process in which, in an agitated bed comprising small polymer particles, first (I) propylene is homopolymerized from the gas phase, in a first polymerization zone, by feeding in a Ziegler-Natta catalyst comprising (1) a titanium(III) component and (2) a dialkyl-aluminum chloride component, with or without (3) a further catalyst component, and then (II) the product obtained in the first polymerization zone is fed into a second polymerization zone, where a mixture of propylene and ethylene is polymerized with the propylene homopolymer present in this product. In this process, the Ziegler-Natta catalyst employed contains a titanium(III) component (1) which is prepared by subjecting (1.1) a titanium-containing compound (a) of the formula TiCl.sub.3. nAlCl.sub.3 and (1.2) an electron donor (b), consisting of (b.sub.1) an ester of a particular class or (b.sub.2) a phosphorus-containing compound of a particular class, to a special milling procedure, the particular features of which are special metering and temperature conditions, suspending the resulting intermediate in a mixture of a liquid hydrocarbon (c) and an oxygen-containing com…