Thermal initiator system using leuco dyes and polyhalogene compounds

摘要

The present invention relates to IR-sensitive compositions containing an initator system comprising: (a) at least one compound capable of absorbing IR radiation selected from triarylamine dyes, thiazolium dyes, indolium dyes, oxazolium dyes, cyanine dyes, polyaniline dyes, polypyrrole dyes, polythiophene dyes and phthalocyanine pigments (b) at least one compound capable of producing radicals selected from polyhaloalkyl-substituted compounds (c) at least one polycarboxylic acid represented by the following formula I wherein Y is selected from the group consisting of O, S and NR7, each of R4, R5 and R6 is independently selected from the group consisting of hydrogen, C1-C4 alkyl, aryl which is optionally substituted, -COOH and NR8CH2COOH, R7 is selected from the group consisting of hydrogen, C1-C6 alkyl, -CH2CH2OH, and C1-C5 alkyl substituted with -COOH, R8 is selected from the group consisting of -CH2COOH, -CH2OH and -(CH2)2N(CH2COOH)2 and r is 0, 1, 2 or 3 with the proviso that at least one of R4, R5, R6, R7 and R8 comprises a -COOH group or salts thereof, and (d) at least one leuco dye, wherein the following inequation is met: oxawith oxa=oxidation potential of component (a) in eV redb=reduction potential of component (b) in eV These compositions are inter alia extraordinarily suitable for the manufacture of printing plates.