Processes for the preparation of polymeric thickeners and uses thereof

A process for preparing a polymer useful as a thickening agent in aqueous polymeric latices comprising:

• (a) adding to a reaction zone about 10 to 50% by weight of the total of the monomers and sufficient ethylene glycol or propylene glycol, with 0 to about 50% by weight of water based on the weight of glycol, to give a final product having a solids content between 5 and 35% by weight, said monomers consisting essentially of (i) about 30-65% by weight of acrylic acid or methacrylic acid, and (ii) about 70-35% by weight of an ester of the formula ##STR10## wherein R is hydrogen or methyl,
• x is a positive integer of 10 to 50, and
• R.sub.3 is an alkyl group of 8 to 20 carbon atoms;
• (b) heating the mixture of (a) to a temperature in the range of about 70.degree. to 110.degree. C.;
• (c) adding to the reaction zone about 2 to 50% by weight of the total of a free-radical polymerization catalyst dissolved in a solvent;
• (d) continuously feeding to the reaction zone the remainder of the monomers and catalyst;
• and
• (e) cooling the reaction product and then adding ammonia or a water-soluble organic amine after the polymerization is complete to adjust the pH to about 7 to 10.