Controlling the particle size in the preparation of polymer powders

US5010150A · kind A · utility

Assignee

• BASF SE

Inventors

• Karl Hennig · Heßheim, DE
• Heinrich Hartmann · Schifferstadt, DE
• Hans-Juergen Raubenheimer · Ketsch, DE

Key dates

• Filing date: Nov 13, 1989
• Grant date: Apr 23, 1991
• Expiry date: Nov 13, 2009

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08F20/06
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

The particle size is controlled in the preparation of hydrophilic polymer powders by polymerization of water-soluble monoethylenically unsaturated monomers in a powder bed in the presence of a polymerization initiator and an inert auxiliary liquid by a method in which a solution of the monomers in an inert auxiliary liquid is divided into fine drops with the aid of a multimaterial nozzle which dips into the powder bed, using an inert gas stream, and the particle size of the resulting polymer powder is regulated by varying the amount of inert gas.