Photosensitive elastomeric polymer composition for flexographic printing plates - processable in semi-aqueous basic solution or solvent systems

摘要

A high molecular weight butadiene/acrylonitrile copolymer is used in a photosensitive composition containing the following:P P(A) 40 to 90% by weight of the total composition of a high molecular weight butadiene/acrylonitrile carboxylated copolymer having a number average molecular weight of 30,000 to 125,000, an acrylonitrile content of 10 to 50%, and a carboxyl content of 1% to 15% by weight. PP(B) 5 to 60% by weight of the total composition of a high molecular weight butadiene/acrylonitrile noncarboxylated copolymer having a number average molecular weight of 50,000 to 100,000, an acrylonitrile content of 10 to 30% so that the combination of the carboxylated and non carboxylated high molecular weight copolymers give a composition with a carboxyl content of 3 to 10%.PP(C) 2 to 40% by weight of the total composition of an addition photopolymerizable ethylenically unsaturated monomer andPP(D) 0.1 to 10% by weight of the total composition of a photoinitiator activatable by actinic radiation.