1-4-Dihydropyridine-containing ir-sensitive composition and use thereof for the production of imageable elements

摘要

Initiator system comprising: (a) at least one substance capable of absorbing IR radiation, (b) at least one compound capable of forming free radicals, and (c) at least one 1,4-dihydropyridine derivative of the formula (I) wherein R¹ is selected from a hydrogen atom, -C(O)OR⁷, an optionally substituted alkyl group, an optionally substituted aryl group and an optionally substituted aralkyl group, R² and R³ are independently selected from optionally substituted alkyl groups, optionally substituted aryl groups, CN and a hydrogen atom, R⁴ and R⁵ are independently selected from -C(O)OR⁷, -C(O)R⁷, -C(O)NR⁸R⁹ and CN, or R² and R⁴ together form an optionally substituted phenyl ring or a 5- to 7-membered carbocyclic or heterocyclic ring, wherein the unit is present in the carbocyclic or heterocyclic ring adjacent to position 5 of the dihydropyridine ring and wherein the carbocyclic or heterocyclic ring optionally comprises additional substituents, or both R² and R⁴ as well as R³ and R⁵ form either optionally substituted phenyl rings or 5- to 7-membered carbocyclic or heterocyclic rings, wherein the unit is present in the carbocyclic or heterocyclic rings adjacent to positions 3 and 5 of the dihydropyridine ring and wherein the carbocyclic or heterocyclic rings optionally comprise additional substituents, or one of the pairs R²/R⁴ and R³/R⁵ forms a 5- to 7-membered carbocyclic or heterocyclic ring, wherein the unit is present in the carbocyclic or heterocyclic ring adjacent to position 5 or 3 of the dihydropyridine ring and wherein the carbocyclic or heterocyclic ring optionally comprises additional substituents and the other pair forms an optionally substituted phenyl ring, or R² and R⁴ or R³ and R¹ form a 5- to 7-membered heterocyclic ring which can optionally comprise one or more substituents and which, in addition to the nitrogen atom it shares with the 1,4-dihydropyridine ring, optionally comprises additional nitrogen atoms, -NR¹³ groups, -S- or -O-, R⁶ is selected from an alkyl group optionally substituted with a halogen atom or a -C(O) group, an optionally substituted aryl group, an optionally substituted aralkyl group, an optionally substituted heterocyclic group and the group Y is an alkylene group or an arylene group, R⁷ is a hydrogen atom, aryl group, aralkyl group or alkyl group, wherein the alkyl group and the alkyl unit of the aralkyl group optionally comprise one or more C-C double and/or C-C triple bonds, and R⁸ and R⁹ are independently selected from a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group and an optionally substituted aralkyl group.