Coating compositions comprising a latent activator for marking substrates
The present invention provides a composition, which comprises a latent activator. It also provides a process for the preparation of these compositions, substrates coated with these compositions and a process for their preparation, a process for preparing marked substrates using these compositions and marked substrates obtainable by the latter process.
1. A coating composition comprising a latent activator,
wherein the latent activator is a salt of an acid and an amine,
wherein the amine is of formula NR 1 R 2 R 3 , wherein R 1 , R 2 and R 3 can be the same or different and are hydrogen, C 1-30 -alkyl, C 2-30 -alkenyl, C 4-8 -cycloalkyl, C 5-8 -cycloalkenyl, aralkyl, aralkenyl or aryl, or R 1 is hydrogen, C 1-30 -alkyl, C 2-30 -alkenyl, C 4-8 -cycloalkyl, C 5-8 -cycloalkenyl, aralkyl, aralkenyl or aryl and R 2 and R 3 , together with the nitrogen of the amine of formula NR 1 R 2 R 3 form a 5- to 7-membered ring, whereby C 1-30 -alkyl, C 2-30 -alkenyl, C 4-8 -cycloalkyl, C 5-8 -cycloalkenyl, aralkyl and aralkenyl can be unsubstituted or substituted with NR 4 R 5 R 6 , imino, cyano, cyanamino, hydroxy and/or C 1-6 -alkoxy, and aryl can be unsubstituted or substituted with NR 4 R 5 R 6 , cyano, cyanamino, hydroxyl, C 1-6 -alkyl, and/or C 1-4 -alkoxy, wherein R 4 , R 5 and R 6 can be the same or different and are hydrogen, C 1-6 -alkyl, C 4-8 -cycloalkyl or aryl, and
wherein the coating composition does not contain a dye or colour former.
2. The coating composition of claim 1 , wherein the acid is selected from the group consisting of inorganic acids, sulfur-based organic acids, phosphor-based organic acids, carboxylic acids and mixtures thereof.
3. The coating composition of claim 1 , wherein the acid derivative is an ester, amide, anhydride or thioester of the acid as defined in claim 2 , wherein all acidic OH-groups are substituted with OR 7 , NR 8 R 9 , OC(O)R 10 or SR 11 , whereby R 7 , R 8 , R 9 , R 10 and R 11 are the same or different and can be hydrogen, C 1-30 -alkyl, C 2-30 -alkenyl, C 4-8 -cycloalkyl, C 5-8 -cycloalkenyl, aralkyl, aralkenyl or aryl, whereby C 1-30 -alkyl, C 2-30 -alkenyl, C 4-8 -cycloalkyl, C 5-8 -cycloalkenyl, aralkyl and aralkenyl can be unsubstituted or substituted with NR 12 R 13 R 14 , halogen, cyano, hydroxy and/or C 1-6 -alkoxy, and aryl can be unsubstituted or substituted with NR 12 R 13 R 14 , halogen, cyano, hydroxyl, C 1-6 -alkyl, and/or C 1-6 -alkoxy, whereby R 12 , R 13 and R 14 can be the same or different and are hydrogen, C 1-6 -alkyl, C 4-8 -cycloalkyl or aryl, provided that R 7 is not hydrogen.
4. The coating composition of claim 1 , wherein the composition also comprises a solvent.
5. The coating composition of claim 1 , wherein the composition also comprises a polymeric binder.
6. The coating composition of claim 1 , wherein the composition also comprises a char forming compound.
7. The coating composition of claim 6 , wherein the char forming compound is selected from the group consisting of carbohydrates and derivatives thereof wherein the carbonyl group has been reduced to a hydroxyl group.
8. The coating composition of claim 1 , wherein the composition also comprises additional components.
9. A process for preparing the coating composition of claim 1 , comprising mixing a latent activator and a solvent.
10. A substrate coated with the coating composition of claim 1 .
11. A process for preparing a coated substrate, comprising the step of coating a substrate with the composition of claim 1 .
12. A process for preparing a marked substrate, comprising the steps of
i) coating a substrate with the composition of claim 1 , and
ii) exposing those parts of the coated substrate, where a marking is intended, to energy in order to generate a marking.
13. The process of claim 12 wherein the energy is selected from the group consisting of UV, IR, visible and microwave irradiation.
14. The process of claim 13 , wherein the energy is IR irradiation.
15. A marked substrate, which is obtained by the process of claim 12 .