Radiation-polymerizable composition and element containing a photopolymer composition

摘要

This invention relates to a radiation polymerizable composition for use in a photographic element such as a lithographic printing plate comprising in admixture (a) a binder resin having the general formula -A-B-C- wherein a plurality of each of components A, B and C occur in ordered or random sequence in the resin and wherein A is present in said resin at about 5% to about 20% by weight and comprises groups of the formula <IMAGE> B is present in said resin at about 4% to about 30% by weight and comprises groups of the formula <IMAGE> and C is present in said resin at about 50% to about 91% by weight and comprises acetal groups consisting of groups of the formulae <IMAGE> where R is lower alkyl or hydrogen, and wherein said group I is present in component C from about 75% to about 85%, group II is present in component C from about 3% to about 5%; and group III is present in component C from about 10% to about 22%. (b) a photoinitiator; (c) a diazonium salt; and (d) a photopolymerizable mixture of (i) an acrylic monomer having two or more unsaturated groups; and (ii) an oligomer which is prepared by reacting one molar equivalent of a substantially linear polymeric compound having an active hydrogen group at each end thereof with at least two molar equivalents of a diisocyanate compound so as to form a prepolymer having an isocyanate group at each end thereof; and subsequently reacting said prepolymer with at least two equivalents of an ethylenically unsaturated compound having an active hydrogen group to provide said prepolymer with unsaturation at each end thereof.