Process for preparing stable, finely divided polymer dispersions

US6103786A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Martin Hoch · Gilching, DE
• Rainer Elbert · Wittlich, DE
• Bernd Klinksiek · Bensberg, DE

Key dates

• Filing date: Feb 24, 1998
• Grant date: Aug 15, 2000
• Expiry date: Feb 24, 2018

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S526/932
• WIPO field: Other special machines
• WIPO sector: Mechanical engineering

Abstract

Stable polymer dispersions with polymer particle sizes of 0.1 to 10 .mu.m are prepared by dissolving a water-in-oil emulsion, comprising a polymer dissolved in an organic solvent which is immiscible with water (organic phase) and an aqueous phase, wherein the viscosity of the organic phase is 1.0 to 20,000 mPas (measured at 25.degree. C.), the surface tension between organic and aqueous phase is 0.01 to 30 mN/m, the particle size of the water emulsified in the organic phase is 0.2 to 50 .mu.m and the ratio by volume of organic phase to aqueous phase is in the range 80:20 to 20:80, subjecting this emulsion to a shear process at a shear power of 1.times.10.sup.3 to 1.times.10.sup.8 Watts per cm.sup.3, wherein the water-in-oil emulsion is converted into an oil-in-water emulsion.