Polymeric material, containing a latent acid

1. Polymeric material containing:

(i) a latent acid, wherein the latent acid is converted to an acid by irradiation by a laser; and

(ii) optionally further ingredients,

wherein the latent acid is of formula

wherein the ring A can contain one or more hetero atoms and/or can contain an anelated ring,

R 1 is hydrogen, alkyl, alkenyl, aryl,

R 2 , R 3 , R 4 and R 5 independently of each other are hydrogen or a functional substituent, and

R stands for C 1 -C 8 alkyl, —Z 1 -Q 1 , or —Z 2 -Q 2 ,

wherein Z 1 is a single bond, S, NH or O, and Q 1 is a heterocyclic ring system having from 5 to 9 ring atoms selected from C, S, O and N, with at least 2 carbon atoms in the ring system, which may be substituted one to three times with C 1 -C 4 alkyl or hydroxy, mercaptobenzoxazole, mercaptobenzthiazole, and

wherein Z 2 stands for C 1 -C 4 alkylene, which can be substituted by C 1 -C 4 alkyl or Q 3 , wherein Q 3 stands for phenyl which can be substituted one to three times with C 1 -C 4 alkyl, hydroxy, C 5 -C 8 cycloalkyl and/or a heterocyclic ring system having from 5 to 9 ring atoms selected from C, S, O and N, with at least 2 carbon atoms in the ring system, and Q 2 stands for phenyl which can be substituted one to three times with C 1 -C 4 alkyl, hydroxy, C 5 -C 8 cycloalkyl and/or a heterocyclic ring system having from 5 to 9 ring atoms selected from C, S, O and N, with at least 2 carbon atoms in the ring system,

with the proviso that the hydrogen atom at the C-atom in α-position to R is split off by irradiation.

2. The polymeric material according to claim 1 , wherein the polymeric material contains 0.001 to 10% by weight of the latent acid.

3. The polymeric material according to claim 1 , wherein the polymeric material further contains a colourless colour former which gives a visible colour after reaction with an acid.

4. The polymeric material according to claim 1 , wherein R 1 is hydrogen or methyl.

5. The polymeric material according to claim 1 , wherein R is a heterocyclic residue, which is bound to the CHR 1 group via a nitrogen, oxygen or sulfur atom or is a C 1 -C 6 alkyl, which is unsubstituted or substituted.

6. The polymeric material according to claim 1 , wherein R is a radical of mercaptobenzoxazol or mercaptobenzthiazole or C 1 -C 4 alkyl which is unsubstituted or substituted by unsubstituted phenyl or phenyl carrying 1 to 4 substituent selected from the group consisting of C 1 -C 6 alkyl, C 1 -C 4 alkyoxy and hydroxyl.

7. The polymeric material according to claim 1 , wherein the polymeric material contains as further ingredient a stabilizer, an antioxidant or a softener.