WATER-SOLUBLE PHOTORESINS BASED ON POLYMERIC AZO-COMPOUNDS

Polymeric azosulfonates lose their water solubility when exposed to UV light due to decomposition of the azo function. This effect can be us ed in water-based photoprinting processes. Water-soluble copolymers of azosulfonate containing repeat units and methyl methacrylate have bee n alternatively synthesized by a polymer-analogous reaction [1,2] and by direct copolymerization [3]. Both polymer types have been evaluated for application as photoresins in offset printing processes. The poly mer made by copolymerization is superior and shows excellent results f or photosensitivity, resolution, film-forming properties, and developm ent in water, as well as for thermal and moisture storage stability.