Photomechanical printing plate prodn - using aldol condensation product of aromatic dialdehyde/aliphatic or aromatic dik

摘要

Photosensitive laminated material for the photomechanical prodn. of printing plates, consisting of a support and a photosensitive coating, comprises the aldol condensn. prod. of an aromatic aldehyde, with is not 2 carbonyl gps. and an aliphatic or aromatic ketone, with is not 2 active sites in the mol. in an alkaline medium. The material obtd. by condensn. is of macromol. structure unlike the familiar prepolymers. It has sufficient strength to form self-supporting films and also has good photosensitivity and ensures excellent reprodn. of tone values. The pref. starting materials are terephthaldehyde and diacetone alcohol. To produce printing plates, the exposed material is developed with dimethylamides or low mol. aliphatic acids and the non-printing areas are made hydrophilic.