Patent ID: 8865620

Claim:
A coating composition comprising a colour developer of formula or mixtures thereof wherein R 1 is hydrogen, C 1-20 -alkyl, C 3-8 -cycloalkyl, C 2-10 -alkenyl, or aryl, and R 2 and R 3 are the same or different and are hydrogen, halogen, C 1-20 -alkyl, C 3-8 -cycloalkyl, C 2-10 -alkenyl, aryl, NR 7 R 8 , SR 9 , SO 3 H or COOR 10 and R 4 and R 5 are the same or different, and are hydrogen, halogen, C 1-20 -alkyl, C 3-8 -cycloalkyl, C 2-10 -alkenyl, or aryl, R 6 , R 7 , R 8 , R 9 and R 10 are the same or different and are hydrogen, C 1-30 -alkyl, C 3-8 -cycloalkyl, C 2-10 -alkenyl or aryl, wherein C 1-20 -alkyl can be unsubstituted or substituted with one or more C 3-8 -cycloalkyl, C 2-10 -alkenyl, phenyl, halogen, OR 11 , NR 12 R 13 , SR 14 , SO 3 H or COOR 15 , and aryl can be unsubstituted or substituted with one or more halogen, C 1-10 -alkyl, halogenated C 1-10 -alkyl, C 3-8 -cycloalkyl, C 2-10 -alkenyl, phenyl, OR 11 , NR 12 R 13 , SR 14 , SO 3 H or COOR 15 , wherein R 11 , R 12 , R 13 , R 14 and R 15 are the same or different and are hydrogen, C 1-10 -alkyl, C 3-8 -cycloalkyl or C 2-10 -alkenyl.