Different sensitising acrylic monomers in Napp printing plate

3 chemically pure fractions were isolated from Napp printing plate and subsequently identified by means of nuclear magnetic resonance, infrared spectrophotometry and elemental analysis. 1 of the fractions elicited positive test reactions in 3 Napp-allergic printers, and another fraction also elicited a positive test reaction in 1 of the printers. The 2 allergens were 2-hydroxyethyl methacrylate and N,N'-methylene-bis-acrylamide. The 1st of the 2 allergens was also demonstrated in another printing plate, Nyloprint WD.