The Dow Chemical Company

Henry Volk

Jack C Lamphere

The stability of a water-soluble acrylate polymer such as sodium polyacrylate in the disperse aqueous phase of a water-in-oil emulsion is improved by the addition to the emulsion of a water-soluble thiosulfate, thiourea, nitrite or thiocyanate, e.g., sodium thiosulfate, in an amount sufficient to improve the viscosity retention of the polymer in an aqueous solution. The resulting emulsion containing the stabilized polymer can be stored for extended periods and then be usefully employed as a flocculant, paper additive and in other conventional applications for said emulsions.

Stabilized water-in-oil emulsions of a polyacrylate

A stable, water-in-oil emulsion of a partially hydrolyzed carboxamide polymer is prepared by contacting a water-in-oil emulsion of an inherently water-dispersible polymer containing carboxamide groups, e.g., polyacrylamide, with a water-in-oil emulsion of a hydrolyzing agent such as sodium hydroxide. By emulsifying the hydrolyzing agent prior to hydrolysis, the hydrolysis reaction can be carried out over a wider range of reaction conditions such as temperature and the like without destroying the water-in-oil emulsion of the polymer.

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Bay City, MI, United States of America

Henry Volk