Dispersing polymeric particles in aqueous medium for coating silver halide emulsion layers

US4022622A · kind A · utility

Assignee

• Agfa-Gevaert NV · BE

Inventors

• Daniel M. Timmerman · Mortsel, BE
• Victor Jan Thijs · Berchem, BE
• Walter F. De Winter · Berchem, BE
• Frans Henri Claes · Mortsel, BE
• Hubert Vandenabeele · Mortsel, BE

Key dates

• Filing date: Mar 1, 1976
• Grant date: May 10, 1977
• Expiry date: Mar 1, 1996

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S430/151
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

Polymeric particles are homogeneously dispersed in aqueous medium by a process which comprises dissolving a water-insoluble film-forming polymer in a water-insoluble, ethylenically unsaturated monomer which is liquid at room temperature. The solution formed is dispersed by stirring in an aqueous solution of a hydrophilic colloid and of a dispersing agent, stirring being continued until a stable dispersing of polymer-in-monomer solution droplets having a diameter between 1 and 10 microns, preferably between 1 and 6 micron, in said aqueous solution is obtained. While continuously stirring the dispersion in the presence of a free-radical forming polymerization initiator, the dispersion is heated at the decomposition temperature of said polymerization initiator to effect polymerization of the water-insoluble, liquid monomer and to form an aqueous dispersion of solvent-free polymer particles. The homogeneously dispersed polymer particles are used in hydrophilic coating compositions as matting agents, particularly in protective layers for photographic materials formed of these hydrophilic coating compositions.