Process for stabilizing acetal carboxylate polymers using dialkyl sulfate

Abstract

The alkali metal, ammonium and alkanol amine salts of polymeric acetal carboxylates are stable detergent builders under laundry use conditions, but depolymerize in acid media, making the polymer fragments more readily biodegradable in waste streams. Now, in the improved process of the present invention for preparing an acetal carboxylate polymer wherein an ester of glyoxylic acid and a polymerization initiator are brought together under polymerization conditions and a chemically stable end group is added to the termini of the resulting polymer to stabilize the polymer against rapid depolymerization in alkaline solution, the improvement comprises adding to the resulting polymer a sufficient amount of an alkali metal hydride, preferably sodium hydride, and a dialkyl sulfate having 1 to about 20 carbon atoms in each alkyl group, preferably dimethyl sulfate, to add to the termini of the resulting polymer an alkyl group derived from the dialkyl sulfate.

Dependencies are inferred from the claim text.