Use of cinnamic acid groups containing acetal polymers for radiation-sensitive compositions and lithographic printing plates

The present invention relates to binders and radiation-sensitive compositions comprising said binders and, Inter alia, are excellently suitable for the production of lithographic plates. Copolymers containing the units A, B, C, D and optionally E are used to prepare radiation sensitive compositions and lithographic printing plates. The copolymer contains about 25 to 55 mol % of unit A which has the formula The copolymer contains about 0.5 to 25 mol % of unit B which has the formula wherein Ris selected from the group consisting of alkyl, aryl and aralkyl.The copolymer contains about 0.5 to 40 mol % of unit C which has the formula wherein X is an aliphatic or aromatic spacer group, and Ac is an acidic group selected from the group consisting of -COOH, -SOH, -SONRRwith Rand Rindependently being selected from hydrogen and alkyl; and when X is phenylene, Ac can also be OH.The copolymer contains about 20 to 70 mol % of unit D which has the formula wherein Ci is selected from the group consisting of Ci-1, Ci-2, Ci-3 and Ci-4 which are represented by the following formulae wherein:k, m and n are integers independently selected from 0 to 5,R, Rand Rare independently selected from the group consisting of alkyl, alkoxy, -COOR, -NRR, -NH-CO-CH, halogen, and cyano,Ris selected from hydrogen and alkyl,Rand Rare independently selected from hydrogen and alkyl,Ris selected from the group consisting of hydrogen, alkyl, aryl and aralkyl,Ris selected from the group consisting of alkyl, aryl and aralkyl andY is selected from the group consisting of alkylene, arylene and arylenealkylene.The copolymer contains about 0 to 50 mol % of unit E which has the formula wherein Ris selected from the group consisting of alkyl, aryl and aralkyl groups.