Preparation of finely divided, gel-like, water-swellable copolymers

US5149750A · kind A · utility

Assignee

• BASF SE

Inventors

• Manfred Niessner · Schifferstadt, DE
• Stefan Wickel · Ludwigshafen, DE
• Wilfried Heide · Freinsheim, DE
• Heinrich Hartmann · Schifferstadt, DE

Key dates

• Filing date: Nov 20, 1989
• Grant date: Sep 22, 1992
• Expiry date: Nov 20, 2009

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S526/93
• WIPO field: Medical technology
• WIPO sector: Instruments

Abstract

Finely divided, gel-like, water-swellable copolymers are prepared by copolymerizing PA0 (a) 100 parts by weight of water-soluble, monoethylenically unsaturated monomers, PA0 (b) from 0.01 to 5 parts by weight of monomers containing two or more ethylenically unsaturated double bonds and PA0 (c) from 0 to 20 parts by weight of water-insoluble, monoethylenically unsaturated monomers in 20-80% strength by weight aqueous solution in the presence of a polymerization initiator and from 0.1 to 10% by weight, based on the monomers used in the copolymerization, of a surfactant, by a process in which the monomers are copolymerized in the presence of initially from 0 to 50% by weight of the amount of surfactant to a conversion of not less than 60%, the remaining amount of surfactant is then added to the reaction mixture and the copolymerization is completed and the resulting gel particles dried.