Process for the preparation of water-in-oil emulsions of water soluble vinyl carboxylic acid polymers and copolymers

In an improved method for the preparation of water-in-oil emulsions of high molecular weight water soluble vinyl carboxylic acid polymers, said method comprising:

• A. forming an emulsion comprising:
• 1. 30-95% by weight of an aqueous phase consisting of water and a water soluble vinyl addition monomer said water soluble vinyl addition monomer containing from 1.0-70.0% by weight of a water soluble vinyl carboxylic acid monomer based on the weight of the monomer;
• 2. 5.0-70.0% by weight of a hydrophilic oil;
• 3. 0.1-21.0% by weight of a water-in-oil emulsifying agent;
• B. polymerizing said emulsion under free radical forming conditions;
• and then,
• C. recovering a water-in-oil emulsion of a high molecular weight water soluble vinyl carboxylic acid polymer;
• the improvement comprising adjusting the pH of the aqueous phase to between 4.5-8.0 prior to polymerization.