Emulsion polymerization of ethylene. I. Polymerization formulas and conditions

Formulas and operating conditions for the emulsion polymerization of ethylene are described. Stable latex products were obtained with a variety of anionic and nonionic emulsifiers, but for the majority of the work fatty acids or polyethoxylated alkyl phenols were used. Potassium persulfate was a satisfactory initiator at concentrations of 0.05–0.50 part per 100 parts of aqueous medium. Substitution of up to 15% of the water with tert ‐butyl alcohol increased the latex particle size and the molecular weight of the polymer. Pressures of 3000–5000 psig and temperatures in the range of 80–100°C. provided practical polymerization rates and stable latex products that could be concentrated by evaporation to 40–50% solids. The concentrated products were fluid and stable during storage for one year or more. Polymer isolated from the latexes exhibited a tensile strength of 1100–1400 psi, an elongation of 30–50%, and a Shore D hardness of 40–45.