Testing trial formulations of liquid zinc primers to be combined with powder top coats
Generating high barrier top coats for anticorrosive coating systems is increasingly performed using powder coatings. Such top coats are usually combined with a priming zinc or zinc containing layer applied via metallisation, (hat dip) galvanisation or via a powder zinc primer. Since each of these methods implicates certain disadvantages, here, some trial formulations of liquid zinc primers are proposed alternatively, which may be combined with a powder top coat. In order to contribute to an advantageaus carbon footprint and a reduced Zn emission, these formulations aimed at improved durability, reduced zinc pigment concentration or a waterbased binder. It is explored to which extent an addition of a degassing agent could prevent pinhole formation in the powder top coat caused by primer solvent residues evaporated during powder top coat curing. Moreover, some test results concerning the proteelive properfies of the zinc primers are reported.