Agfa Gevaert Nv

Frans Henri Claes

Daniel M Timmerman

Walter F De Winter

Hubert Vandenabeele

Victor Jan Thijs

Luc H Leenders

Jan A Van Den Bogaert

Gentil Verbeke

Marcel Jan Libeer

Kudolf Van Den Bergh

A method for recording an image of ionizing radiation comprising the steps of:

Method for recording an image of ionizing radiation

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.

Dispersing polymeric particles in aqueous medium for coating silver

Silver halide emulsions are prepared by silver halide precipitation in the presence of a reducing agent, physical ripening and, if desired, chemical ripening wherein subsequent to the addition of reducing agent and before the grains have reached their final size an oxidizing agent is added to the emulsion. By means of the reducing and oxidizing agents, the gradation and photosensitivity characteristics of the emulsion can be controlled at will.

Method of preparing photographic silver halide emulsions

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 polymerisation initiator, the dispersion is heated at the decomposition temperature of said polymerisation initiator to effect polymerisation 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.

Growing community of inventors

Boechout, Belgium

Frans Henri Claes