Radiation-sensitive mixtures comprising IR-absorbing cyanine dyes having a betaine structure or having a betaine structure and containing an anion, and recording materials prepared therewith

摘要

The invention relates to a positive-working, radiation-sensitive mixture which contains an organic polymeric binder which is insoluble in water but soluble or at least swellable in aqueous alkaline solution and at least one IR-absorbing cyanine dye having a betaine structure or having a betaine structure and containing an anion and having the formula (I) ;in which;R¹ to R⁸ independently of one another, are a hydrogen or halogen atom, a sulfonate, carboxylate, phosphonate, hydroxyl, (C₁-C₄)alkoxy, nitro, amino, (C₁-C₄)alkylamino, di(C₁-C₄)alkylamino group or a (C₆-C₁₀)aryl group which in turn may be substituted by one or more halogen atoms and/or one or more sulfonate, carboxylate, phosphonate, hydroxyl, (C₁-C₄)alkoxy, nitro, amino, (C₁-C₄)alkylamino and/or di(C₁-C₄)alkylamnino groups,;R⁹ and R¹⁰ independently of one another, are a straight-chain or branched (C₁-C₆)alkyl, a (C₇-C₆)aralkyl or a (C₆-C₁₀)aryl group, each of which in turn may be substituted by one or more halogen atoms and/or one or more sulfonate, carboxylate, phosphonate, hydroxyl, (C₁-C₄)alkoxy, nitro, amino, (C₁-C₄)alkylamino and/or di(C₁-C₄)alkylamino groups,;R¹¹ and R¹² independently of one another, are (C₁-C₄)alkyl or (C₆-C₁₀)aryl groups which in turn may be substituted,;Z¹ and Z² independently of one another, are a sulfur atom, a di(C₁-C₄)alkylmethylene group or an ethene-1,2-diyl group and;A is a carbon atom or a chain having conjugated double bonds which results in the formation of a delocalized II-electron system between the quaternary nitrogen atom of the 3H-indolium, quinolinium or benzothiazolium radical and the enolate oxygen atom of the pyrimidine-2,4,6-trione radical.;After imagewise exposure to a laser, the recording material prepared using this mixture can be readily developed with an aqueous alkaline solution without additional processing steps (such as post-bake or postexposure). The invention also relates to a process for the production of printing plates for offset printing from a recording material according to the invention.