Process for preparation of quaternized cationic vinyllactam-acrylamide copolymers

Claim 1

The process which comprises the steps sequentially in combination: A. copolymerizing between about 30 and 95 percent by weight of a N-vinyllactam having the formula: ##STR6## wherein R is hydrogen, methyl or ethyl and n is an integer of 1 to 3, with between about 5 and about 70 percent by weight of acrylamide or methacrylamide in a nonacidic aqueous solution in the presence of a free radical catalyst at a temperature of between about 25° and about 150° C.; B. reacting the resulting copolymer with formaldehyde and a secondary amine having the formula: ##STR7## wherein R 2 and R 3 are independently selected from the group consisting of alkyl having from 1 to 4 carbon atoms, hydroxyalkyl having from 1 to 4 carbon atoms and together may represent morpholine, to produce the corresponding cationic vinyllactam-acrylamide copolymer; and C. quaternizing the cationic polymer by reacting with a compound selected from the group consisting of a benzyl halide, an alkyl halide having from 1 to 6 carbon atoms, an alkyl sulfate having from 1 to 6 carbon atoms, an alkyl ester of sulfonic acid having from 1 to 6 carbon atoms and mixtures thereof to produce a quaternized copolymer having a K value less than 200 consisting essentially of the following recurring units in primarily random distribution: ##STR8## wherein R, R 2 , R 3 and n are as defined above; R 1 is selected from the group consisting of hydrogen and methyl; R 4 is selected from the group consisting of alkyl having 1 to 6 carbon atoms and benzyl radicals in an amount of 10 to 100% by weight and hydrogen in an amount of 0 to 90% by weight; X represents an anion; Z is selected from the group consisting of hydrogen and ##STR9## wherein R 2 , R 3 , and R 4 are as defined above; a represents from 30 to 95 percent by weight of the lactam moiety in the copolymeric product; b represents from 5 to 70 percent by weight of the acrylamide moiety in said copolymeric product.