Suspension polymerization of vinyl halide products

Claim 1

IN A PROCESS FOR PREPARING POLYMERIZATION PRODUCTS IN GRANULAR FORM, THE IMPROVEMENT WHICH COMPRISES POLYMERIZING AN AQUEOUS DISPERSION OF A POLYMERIZABLE MATERIAL CONTAINING A VINYL HALIDE FROM THE GROUP CONSISTING OF VINYL FLUORIDE, VINYL CHLORIDE AND VINYL BROMIDE IN THE PRESENCE OF, AS A DISPERSING AGENT, AN INTERPOLYMER OF A MONOMERIC MIXTURE CONSISTING OF ESSENTIALLY EQUIMOLAR PROPORTIONS OF ETHYLENE AND A MALEIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF MALEIC ACID, MALEIC ANHYDRIDE AND MIXTURES THEREOF, SAID INTERPOLYMER BEING PARTIALLY ESTERIFIED WITH A MONOHYDRIC ALCOHOL CONTAINING 1-10 CARBON ATOMS, SAID DISPERSING AGENT BEING FURTHER CHARACTERIZED BY (1) THE INTERPOLYMER OF ETHYLENE AND THE MALEIC COMPOUND, PRIOR TO ESTERIFICATION AND WHEN IN THE ANHYDRIDE FORM, HAVING A SPECIFIC VISCOSITY OF AT LEAST 1.1, AS DETERMINED IN A 1% SOLUTION IN DIMETHYLFORMAMIDE AT 25*C., (2) HAVING UP TO 15 MOL PERCENT OF THE CARBOXYL GROUPS OF THE INTERPOLYMER ESTERIFIED WITH SAID MONOHYDRIC ALCOHOL AND BEING OTHERWISE FREE OF REACTIVE FUNCTIONAL GROUPS, THE ALCOHOL PORTION OF SAID ESTER GROUPS CONSTITUTING NOT OVER 210 WEIGHT PERCENT OF THE DISPERSING AGENT, AND (3) BEING FREE OF SALT GROUPS.