MODIFIED POLYMERS AND THEIR USE IN THE PRODUCTION OF LITHOGRAPHIC PRINTING PLATE PRECURSORS

摘要

Radiation-sensitive negative working element comprising (a) a substrate with a hydrophilic surface and (b) a layer on the hydrophilic surface of the substrate, wherein said layer comprises a modified polymer obtainable by reacting (i) a polymer with -COOH, -SO3H, -P03H2 and/or -PO4H2 in the side chains, wherein the polymer is soluble in aqueous alkaline solutions and the solubility is not changed by IR radiation, and (ii) a salt with an inorganic or organic cation, wherein the modified polymer is soluble in aqueous alkaline solutions and the solubility is not changed by IR radiation, said layer being soluble in aqueous alkaline developer, but is rendered insoluble in aqueous alkaline developer by IR radiation.