Not all substrates that are to be coated can withstand the mechanical or thermal effects that would be necessary to successfully apply a professional property-giving or decorative coating.

A prerequisite for the adhesion of bonding partners during coating is good wettability of the surface. Wetting is not only prevented by oil- and grease-containing dirt or dust, even a clean surface of many materials cannot be sufficiently wetted by many liquids. The liquid beads off. Even after the sintering process is complete, the applied products may not adhere to the surface.

The reason is that the surface energy of the substrate is too low. Substances with low surface energy wet those with high surface energy, but unfortunately not vice versa. The surface energy of the applied dispersion varnish, which we refer to as the surface tension of the varnish, must therefore be lower than that of the substrate to which the varnish is to be applied.

Metals, ceramics and glass generally have a higher surface energy than plastics. Nevertheless, there are also applications with these materials where plasma activation creates advantages.

However, the activation of metals is very unstable and therefore only short-lived. In our process, therefore, plasma activation and the application of the dispersion are switched directly one after the other in order to achieve an optimum coating result.