PRODUCTION OF POLYVINYL ACETATE EMULSION

PURPOSE:To obtain a polyvinyl acetate emulsion capable of forming films with improved transparency, by emulsion-polymerizing a vinyl acetate (co)monomer in the presence of a water-soluble polymer compound, adding an aqueous PVA solution thereto and then aging the mixture. CONSTITUTION:A vinyl acetate monomer or comonomer is emulsion-polymerized with the aid of a water-soluble polymer. After adding an aqueous polyvinyl alcohol solution, the reaction mixture is heated with agitation to effect its aging. As the water-soluble polymer compound, polyvinyl alcohol is generally used. As the polyvinyl alcohol which is added afterwards, a partially saponified polyvinyl alcohol having a relatively high degree of polymerization (e.g. 1,700-2,500) is preferred. In the above process, the aging reaction is effected by adding polyvinyl alcohol again after the emulsion polymerization and the monomer remaining in the emulsion begins polymerization and forms new particles. This lowers the content of a remaining monomer in the final product.