Patent ID: 8920606

Claim:
A method for preparing a cellulose reactive functionalized polyvinylamide adduct using a continuous process comprising: continuously reacting a substantially aqueous reaction mixture of a vinylamide polymer comprising at least about 70 wt. % acrylamide monomer or methacrylamide monomer and 0 to about 30 wt. % cationic monomer selected from the group consisting of diallyldialkyl ammonium salts, (dialkylamino)alkyl(meth)acrylates acid addition or quaternary salts, 2-vinylpyridines acid addition or quaternary salts, dialkylamino alkyl(meth)acrylamides acid addition or quaternary salts, (p-vinylphenyl)-trimethylammonium chloride, 1-methacryloyl-4-methyl piperazine, and acid addition or quaternary ammonium salts thereof; and a cellulose reactive agent selected from the group consisting of glyoxal, glutaraldehyde, furan dialdehyde, 2-hydroxyadipaldehyde, succinaldehyde, dialdehyde starch, diepoxy compounds, and combinations thereof, at a temperature of about 2° C. to about 50° C. and a reaction pH set point of about 8.5 to about 12, for a reaction time of about 2 minutes to about 150 minutes, wherein: i) the temperature of incoming water is continuously measured; ii) the pH of the reaction mixture is adjusted to maintain an approximately constant reaction rate based on the following equation: pH=−0.0404 T+ 10.961 where: pH=reaction pH set point T=reaction temperature (° C.); iii) between 12% and 85% of the cellulose reactive agent is consumed, and the molar ratio of the amide functionality on the vinylamide polymer to cellulose reactive agent is between 6 to 1 and 2.5 to 1; and iv) the concentration of the vinylamide polymer prior to and during formation of the adduct is about 0.5-6% of the total reaction mixture, thereby forming the adduct.