| abstract |
A conjugated diene copolymer comprising (A) 10 to 60 mole % of conjugated diene compound units. (B) 5 to 50 mole % of a, β-ethylenically unsaturated carboxylic acid units. (C) 0.1 to 20 mole % of polyfunctional alkenyl compound units. (D) 0 to 10 mole % of diene compound units having carbon-carbon double bonds in a carbocyclic system and (E) 0 to 80 mole % of monoolefinically unsaturated compound units, the sum of the amounts of units (A), (B), (C), (D), and (E) being 100 mole %, and having an intrinsic viscosity (η) of 0.01 to 3.0 dl/g (measured at 30°C in dimethyl-formamide) is soluble in aqueous alkali solutions, excels in processability and photosetting property, and has excellent rubber elasticity and transparency even after photosetting. Accordingly, a photosensitive composition comprising the copolymer, a photopolymerizable unsaturated monomer and a photosensitizer can greatly improve the complicated process for the production of conventional rubber relief plates of flexographic printing, and shorten the production time. |