To provide a method for producing an aqueous ethylene-vinyl acetate copolymer emulsion whose non-volatile matter content is at least 70 wt% and the viscosity is not more than 5000 mPa×s and having excellent flowability even under a low temperature.
Method for producing an aqueous emulsion, which contains an ethylene-vinyl acetate copolymer having a glass transition temperature of +10 to -30°C and whose non-volatile matter content is at least 70 wt% and the viscosity is not more than 5,000 mPa×s, by controlling the rate of polymerization within a definite range in the initial stage of polymerization. Desirably, by using emulsifying dispersant of 2-6 pts.wt. against vinyl acetate of 100 pts.wt. The emulsifying dispersant contains polyvinyl alcohol, whose saponification degree is ≥80 mol% and average polymerization degree is 200-500, and a poly(oxyethylene) nonionic surfactant of 10-20HLB. The 10-50% of total amount of polyvinyl alcohol to be used is applied at the start of polymerization and the 50-90% is to be supplied during polymerization.
ISE KATSUTOSHI
Toru Nakayama
Masayuki Enomoto