Polymer emulsions with vinyl acetate-polyoxyalkylene compound copolymer as stabilizer

Claim 1

A PROCESS FOR THE PREPARATION OF STABLE AQUEOUS EMULSIONS OF POLYMERS WHICH COMPRISES (1) DISSOLVING IN WATER A WATER-SOLUBLE EMULSIFYING AGENT OF THE GROUP CONSISTING OF COPOLYMERS OF NIVYL ACETATE AND A POLYOXYALKYLENE GLYCOL, AND HYDROLYZED DERIVATIVES OF SAID COPOLYMERS, SAID HYDROLYZED DERIVATIVES HAVING BEEN FORMED BY HYDROLYZING AT LEAST A PORTIN OF THE ACETOXY GROUPS OF THE COPOLYMER TO HYDROXYL GROUPS, SAID COPOLYMERS HAVING BEEN FORMED BY REACTING VINYL ACETATE WITH A POLYOXYALKYLENE GLYCOL HAVING A MOLECULAR WEIGHT OF AT LEAST 400 TO FORM A COPOLYMER, UNDER SUBSTANTIALLY ANHYDROUS CONDITIONS, (2) ADDING A POLYMERIZABLE MONOMER OF THE GROUP CONSISTING OF STYRENE, THE VINYL ESTERS OF THE LOWER ALKANOIC ACIDS, THE LOWER ALKYL ESTERS OF ACRYLIC ACID AND THE LOWER ALKYLESTERS OF METHACRYLIC ACID AND POLYMERIZABLE MIXTURES THEREOF, (3) STIRRING TO EMULSIFY SAID MONOMER IN THE AQUEOUS MEDIUM, (4) ADDING TO THE RESULTANT EMULSION A MATERIAL WHICH IS EFFECTIVE AS AN EMULSION POLYMERIZATION CATALYST FOR SAID MONOMER AT A TEMPERATURE BETWEEN 20*C. AND THE REFLUX TEMPERATURE OF THE EMULSION, AND (5) SUBJECTING THE EMULSION TO POLYMERIZING TEMPERATURES IN THE RANGE BETWEEN 20*C. AND THE REFLUX TEMPERATURE OF THE POLYMERIZING EMULSION, THE TOTAL WEIGHT OF MONOMER ADDED BEING BETWEEN 30% AND 60% OF THE WEIGHT OF THE EMULSION PRODUCT AND THE TOTAL WEIGHT OF THE VINYL ACETATE-POLYOXYALKYLENE GLYCOL COPOLYMER BEING BETWEEN 5% AND 25% OF THE WEIGHT OF SAID MONOMER, WHEREBY A STABLE AQUEOUS EMULSION OF THE POLYMER IS FORMED.