Water base interpolymer coatings

Claim 1

THE PROCESS FOR PRODUCING AN INTERPOLYMER COATING COMPOSITION IN AQUEOUS DISPERSION BY AT LEAST TWO SEQUENTIAL STEPS OF ADDITION POLYMERIZATION OF MONOMER MATERIALS WHICH CONTAIN AND ARE POLYMERIZABLE THROUGH AT LAST ONE ETHENOID GROUP, IN THE PRESENCE OF A FREE RADICAL POLYMERIZATION CATALYST; WHICH PROCESS COMPRISES (A) DISPERSING, IN AN AQUEOUS MEDIUM CONTAINING A FREE RADICAL POLYMERIZATION CATALYST AND FROM 0.0 TO 0.5% BY WEIGHT OF AN EMULSIFIER BASED ON THE WEIGHT OF SAID MONOMER MATERIALS, FROM 50 TO 97% BUTADIENE AND FROM 3 TO 50% OF ACRYLONITRILE, (B) POLYMERIZING SAID MONOMER MATERIALS IN A FIRST STEP TO PRODUCE A POLYMER THEREOF IN SAID AQUEOUS DISPERSION, (C) DISPERSING AT LEAST TWO DIFFERENT SUCH MONOMER MATERIALS IN SAID AQUEOUS DISPERSION OF SAID PRODUCED POLYMER, (D) POLYMERIZING SAID MONOMER MATERIALS WITH SAID POLYMER IN SAID AQUEOUS DISPERSION IN THE PRESENCE OF A FREE RADICAL POLYMERIZATION CATALYST AND FROM 0.0 TO 0.5% BY WEIGHT OF AN EMULSIFYING AGENT BASED ON THE WEIGHT OF THE POLYMER AND MONOMER IN STEP (C), IN A SECOND STEP (E) ONE OF SAID MONOMER MATERIALS IN AT LEAST ONE OF SAID POLYMERIZATION STEPS BEING VINYLIDENE MONOMER MATERIAL SELECTED FROM THE GROUP CONSISTING OF VINYLIDENE FLUORIDE, VINYLIDENE CHLORIDE, AND VINYLIDENE CYANIDE, AND MIXTURES OF THE FOREGOING, (F) THE POLYMERIZED VINYLIDENE MONOMER CONSTITUTING AT LEAST 50% BY WEIGHT OF THE TOTAL INTERPOLYMER OF THE COMPOSITION, (G) THE MIXTURE OF MONOMER MATERIALS COPOLYMERIZED IN SAID STEP (B) RESULTING IN THE FORMATION OF A FLEXIBLE, FILM-FORMING POLYMER, (H) AT LEAST ONE OF SAID POLYMERIZATION STEPS BEING EFFECTED IN THE PRESENCE OF AN EMULSIFYING AGENT, AND (I) REMOVING THE RESULTING FLEXIBLE, FILM-FORMING INTERPOLYMER COMPOSITION IN AN AQUEOUS DISPERSION HAVING A SOLIDS CONTENT NOT IN EXCESS OF 60%.