Patent ID: 8901266

Claim:
A process for producing a copolymer of diallyldialkyl ammonium salt and maleic acid, which comprises polymerizing a monomer mixture comprising diallyldialkyl ammonium salt of the following general formula (I), wherein each of R 1 and R 2 is independently an alkyl group having 1 to 3 carbon atoms and X − is a counter ion, and maleic acid of the following formula (II), in the presence of persulfate as a radical polymerization initiator in water or a polar solvent, and, after completion of the polymerization reaction, decomposing the radical polymerization initiator by heat treatment to produce a copolymer comprising a diallyldialkylammonium salt constituent unit of the general formula (III) or (IV), wherein each of R 1 and R 2 is independently an alkyl group having 1 to 3 carbon atoms and X − is a counter ion, and a maleic acid constituent unit of the following formula (V),