Photosensitive compositions and printing plates containing same

Abstract

A photosensitive resin composition comprising (I) a copolymer containing (A) 10 to 95 mol % of a conjugated diolefinic hydrocarbon, (B) 5 to 90 mol % of an .alpha.,.beta.-ethylenically unsaturated carboxylic acid and (C) 0 to 85 mol % of a monoolefinically unsaturated compound, (II) a photosensitizer and/or a photosensitive crosslinking agent, and, if necessary, (III) a photopolymerizable unsaturated monomer. Said copolymer may have been reacted with an inorganic alkali, an alkali salt or an amine compound in a proportion of 0.05 to 1.0 equivalent per equivalent of the carboxyl group of the .alpha.,.beta.-ethylenically unsaturated carboxylic acid in said copolymer. This photosensitive resin composition is excellent in storage stability, quick in photosetting upon exposure to actinic light rays including ultraviolet rays, that is, high in sensitivity, capable of development with water or a dilute aqueous alkaline solution and possesses satisfactory rubber elasticity, and a printing plate formed from the composition is excellent in water resistance though the composition is developable with an aqueous developing solution, so that the composition can be used for a flexographic printing plate, to which an aqueous flexographic printing ink can be applied. Said composition can also be used for a pohote-resist which is high in sensitivity, developable with water or a dilute alkaline solution and excellent in resolving power.

Dependencies are inferred from the claim text.