Patent ID: 6197865
Filing Date: 2001-03-06
Classification: C08F

Abstract:
A process for producing an aqueous emulsion having a solid content of 70% by weight or more, a viscosity of 5,000 mPa.s or less and containing an ethylene-vinyl acetate copolymer having 10-40% by weight of ethylene units and 90-60% of by weight of vinyl acetate units, wherein said process comprises:(1) mixing in a copolymerization reaction:i) 50-90% of the total amount of vinyl acetate used in the process;ii) an emulsifying dispersant comprising a polyvinyl alcohol and a polyoxyethylene nonionic surfactant;wherein said dispersant is present in 2-6 parts by weight per 100 parts by weight of said vinyl acetate, said polyvinyl alcohol has a degree of hydrolysis of 80% or more by mole and an average degree of polymerization of 200 to 1000, said polyoxyethylene nonionic surfactant has a hydrophilic-lipophilic balance of 10 to 20,and wherein said polyvinyl alcohol in the dispersant comprises 10 to 50% of the total amount of polyvinyl alcohol used in the process;2) initiating the copolymerization reaction;3) adding the remaining 50% to 10% of said vinyl acetate used in the process and the remaining 50% to 90% of the polyvinyl alcohol;wherein the total amount of said emulsifying dispersant is 2 to 6 parts by weight per 100 parts by weight of vinyl acetate and the total amount of said polyvinyl alcohol is 0.4 to 3 parts by weight per 100 parts by weight of said vinyl acetate and the amount of said polyoxyethylene nonionic surfactant is 1 to 5 parts by weight per 100 parts by weight of said vinyl acetate;to obtain an aqueous emulsion having a solid content of 70% by weight or more, a viscosity of 5,000 mPa.s or less and containing an ethylene-vinyl acetate copolymer having 10-40% by weight of ethylene units and 90-60% of by weight of vinyl acetate units.