"crylate; and pentaerythritol tetraacrylate, and said prepolymer (2) being the addition polymerization product of (i) about 5 mole percent to 100 mole percent of a cationic monomer having the formula ##STR31## wherein R1 is hydrogen or methyl, R2 is hydrogen or a C1 -C4 alkyl, R3 is hydrogen, a C1 -C4 alkyl, ##STR32## where Y is hydroxyl or halogen, ##STR33## where in is an integer 1 or more and X-" . . . .