positive working photosensitive flachdruckplatten and methods for their manufacture

摘要

The photosensitive coating for a lithographic printing plate contains (a) a naphthaquinone-(1,2)-diazide-(2)-5-sulphonic acid derivative, (B) a novolak resin which is soluble in alkali and (C) a polymer of a carboxylic acid. The presence of (C) improves the service life of the plate. Specifically (C) is from cellulose acetate phthalate, alkyd resins, phthalate resins and maleic anhydride/styrene copolymers containing carboxyl groups.