In principle the drying process of metallic paints is the same as that of conventionally pigmented systems. Drying time is determined primarily by the resin type and solvent composition. ln the present case, the high boiling component is too pronounced. lt could also be due to the metallic pigments.
At too high a concentration, their generally desirable distinct orientation parallel to the substrate may restrict solvent evaporation. Such pigments exert a blocking effect because of their considerable size so that the solvent can escape only with difficulty from the lower layers.
Metallic pigment concentrations should thus be kept as low a possible without, of course, impairing the metallic opacity.