Laser marking of coatings

Laser marking of coatings on plastics can be realized nowadays by the ablation of laser sensitive coatings, when additional supporting coatings are applied beneath them. By a modification of laser sensitive coatings with special additives, it was possible to perform the laser marking without a supporting coating and thus to simplify the laser marking process. An interesting alternative to the ablative laser marking of coatings represents the non-ablative process. However, it can not be realized by a conventional carbonization or foaming of coatings without their complete or at least partial damage. By a modification of laser sensitive coatings with thermochromic additives and the usage of optimal laser parameters, the non-ablative laser marking was achieved, without any significant damage of the coating.