Elcometer 139 Amine Blush Chip Screen Kit, 20 Tests: Detects amine blush based on the presence of carbamate compounds and not on physical phenomena such as pH. Amines that have migrated to the coating surface can react with CO2 resulting in the formation of carbamates.
This can be observed as an oily film on the surface but is often invisible to the eye. The presence of amine blush will cause inter-coat adhesion failures if a further coat is applied without prior removal of amine blush. It is essential to establish if the coating exhibits the phenomenon of amine blush when determining if an amine cured epoxy coating can be over coated.