Patent ID: 8822589

Claim:
A process for the preparation of an aqueous formulation, comprising: (1) free radically copolymerizing: (A) at least one ethylenically unsaturated carboxylic acid, (B) at least one heterocyclic comonomer having at least one permanent cationic charge per molecule, and (C-P1) at least one ethylenically unsaturated dicarboxylic acid or an anhydride thereof, to produce a copolymer, and adding an ethylenically unsaturated dicarboxylic acid (C-P2) or an anhydride thereof after at least 90% of the period in which the copolymerization is desired or after the end of the copolymerization, wherein not more than 5% by weigh of the ethylenically unsaturated dicarboxylic acid (C-P2) or an anhydride thereof, based on the total weight of the ethylenically unsaturated dicarboxylic acid (C-P2) or an anhydride thereof, is incorporated into the copolymer in the form of polymerized units.