摘要 |
A substrate coated with a markable ink formulation, comprising a thermo activated acid generator (TAG) and a halochromic leuco dye. The thermo activated acid generator is selected form the group consisting of: an amine salt of an organic metal compound comprising boron or silicone and amine neutralized polyalkylnaphthalene polysulphonic acid derivatives. Further, the substrate is covered by a thermoplastic polymer layer, such that the ink formulation is situated between the substrate and the thermoplastic polymer layer and/or in the thermoplastic polymer layer. |