Cationic hydrogels based on heterocyclic N-vinyl monomers

Claim 1

The cationic, polymeric hydrogel produced by simultaneus polymerization and cross-linking in the presence of a free radical polymerization catalyst in an amount of from about 0.05 to about 4 weight percent, based on the total weight of monomers, and at a temperature of from about 20° C. to about 125° C., of a mixture consisting essentially of the following monomers: a. about 20 to about 95 weight percent, based on the total weight of monomers, of a heterocyclic N-vinyl monomer selected from the group consisting of N-vinyl lactams, N-vinyl succinimide, N-vinyl diglycoylimide, N-vinyl glutarimide, N-vinyl-3-morpholinone, N-vinyl-5-methyl-3-morpholinone and N-vinyl imidazole; b. about 50 to about 0.05 weight percent, based on the total weight of monomers, of a cationic monoethylenically unsaturated quaternary ammonium monomer, capable of copolymerizing with (a) and having the formula: ##STR13## wherein: R represents hydrogen, methyl or aryl; R 1 represents hydrogen or alkyl of 1 to about 18 carbons; A and A 1 , each of which may be the same or different, each represents an alkylene group of from about 2 to about 8 carbons or an arylene group; R 2 , r 3 and R 4 , each of which may be the same or different, each represents alkyl, aryl or alkaryl or the R 2 and R 3 on the same nitrogen atom, taken together represent a divalent aliphatic group of 4 to 5 atoms which jointly with the amino nitrogen forms a 5 or 6 membered heterocyclic amino group; X and Y, each of which may be the same or different, each represents an anion forming the anionic portion of a quaternary ammonium group; n represents an integer, including 0, of from 0 to about 10; and m represents an integer, including 0, of from 0 to about 5. c. about 0.2 to about 12 weight percent, based on the total weight of monomers, of a polymerizable cross-linking agent capable of copolymerizing with (a) and (b); and having the formula: ##STR14## wherein R represents a member of the group consisting of hydrogen and alkyl of from 1 to about 4 carbon atoms; A represents alkylene of from 2 to about 10 carbons or a polyglycol ether group of the formula: ##STR15## R' represents a member of the group consisting of hydrogen and alkyl of 1 to 2 carbon atoms; and n represents an integer of from 1 to about 20; and d. from 0 to about 50 weight percent, based on the total weight of monomers, of a monoethylenically unsaturated acrylic monomer capable of copolymerizing with (a), (b) and (c) and capable of polymerizing to a high molecular weight, in excess of 100,000 and selected from the group consisting of acrylamides, methacrylamides, acrylonitrile, methacrylonitrile, alkyl acrylates and methacrylates, hydroxyalkyl acrylates and methacrylates, and monohydroxy and monoalkoxy polyalkylene glycol acrylates and methacrylates; and provided that (a) ≧ (d) and (a)+(d) = about 40 to about 95 weight percent.