Preparation of finely divided, water-soluble polymers

US5258473A · kind A · utility

Assignee

• BASF SE

Inventors

• Manfred Niessner · Schifferstadt, DE
• Stefan Wickel · Ludwigshafen, DE
• Walter Schneider · Thalwil, CH
• Juergen Beck · Mannheim, DE
• Heinrich Hartmann · Schifferstadt, DE
• Thomas A. Meyer · Zuchwil, CH

Key dates

• Filing date: Mar 1, 1991
• Grant date: Nov 2, 1993
• Expiry date: Mar 1, 2011

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08F2/10
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Finely divided, water-soluble polymers are prepared by polymerization of water-soluble, monoethylenically unsaturated monomers in not less than 20% strength by weight aqueous solution in the presence of a polymerization initiator in a kneader by a process in which from 0.1 to 10% by weight, based on the total monomers, of a surfactant are used in the polymerization, the polymerization initially being carried out to a conversion of the monomers of not less than 60% in the absence of the surfactant or in the presence of not more than 50% of the amount of surfactant, and the remaining amount of surfactant then being added to the reaction mixture and the polymerization completed. The addition of surfactant causes the polymer gel to disintegrate with formation of fine particles.