Process for the production of lithographic printing forms using a light-sensitive material based on diazonium salt polycondensation products

Claim 1

A process for the production of a lithographic printing form which comprises imagewise exposing a negative-working light-sensitive layer on a support having a hydrophilic surface suitable for lithographic printing, and washing away the unexpos-ed layer areas with an alkaline solution containing water exclusively as a solvent, said light-sensitive layer containing as the light-sensitive compound a condensation product with recur-rent units A-N2X and B which are linked by bivalent intermediate members derived from a carbonyl compound which is capable of condensation, the units A-N2X being derived from compounds of the general formula-(R1-R3-)pR2-N2X in which X is the anion of the diazonium compound, p is an integer from 1 to 3, R1 is a carbocyclic or heterocyclic aromatic radical which is capable of condensation in at Least one position, R2 is an arylene group of the benzene or naphthalene series, R3 is a single bond or one of the groups -(CH2)q-NR4-, -O-(CH2)r-NR4-, S-(CH2)r-NR4-, -S-CH2-CO-NR4 -, -O-R5-O-, Hoe 81/K 045 -O--S-, or wherein q is a number from 0 to 5, r is a number from 2 to 5, R is a hydrogen atom, an alkyl group having from 1 to 5 carbon atoms, an aralkyl group having from 7 to 12 carbon atoms or an aryl group having from 6 to 12 carbon atoms, and R5 is an arylene group having from 6 to 12 carbon atoms, and B denotes the radical of an aromatic amine, phenol, thio-phenol, phenol ether, aromatic thioether, aromatic hydrocarbon, aromatic heterocyclic compound, or organic acid amide, which is free of diazonium groups, the condensation product containing, on an average, from 0.01 to 50 B units for each A-N2X unit, and, as a binder, a copolymer of styrene and maleic anhydride or a partial ester of maleic acid.