Atmospheric pressure plasma coatings

Environmentally friendly, inline-compatible thin plasma polymer coatings prevent harmful additive migration between polymers and adhesives. This significantly extends the long-term stability of adhesive bonds.

Prevent stress cracks and adhesion loss

In the joint IGF project PlasmaProtect, Fraunhofer IFAM in Bremen and SKZ in Würzburg worked on improving the quality of adhesive bonds. Using atmospheric pressure plasma coatings, they searched for effective barrier protective layers that prevent additive migration between polymers and adhesives, thereby increasing the long-term stability of the resulting adhesive bonds.

To achieve this goal, the experts investigated the challenges of additive migration in polymer adhesive bonds, which can lead to stress cracks and loss of adhesion. Two industrial damage cases were analyzed: adhesive-induced and plastic-induced damage to the adhesive bond.

Efficient and dry coating process

In the frame of the project, a test method was developed to assess the stress crack sensitivity of plastics to adhesives and primers. This enabled critical, application-relevant composite combinations to be identified for further investigation.

Various coating systems were then tested, which were applied locally, dry, and needs-based onto the polymers using inline-capable atmospheric pressure plasma technology. Organosilicon coatings proved to be particularly effective against adhesive-induced damage. These improved both stress crack resistance and adhesive strength. Amorphous carbon-hydrogen coatings, on the other hand, proved to be highly effective in preventing plastic-induced damage.

A process with far-reaching advantages

The results of the project offer a clear added value for large and small and medium-sized enterprises (SMEs) in various industrial sectors: The adhesive bonds made from the environmentally friendly coated polymers are characterized by a longer service life and greater reliability. This minimizes downtime and reduces maintenance costs. This opens up new possibilities for plastics in demanding adhesive applications and creates attractive market opportunities, especially for SMEs. PlasmaProtect shows that atmospheric pressure plasma coatings are a promising solution for improving the long-term stability of adhesive bonds.

The “PlasmaProtect” research project of the research association Fördergemeinschaft für das Süddeutsche Kunststoff-Zentrum e.V. (FSKZ) was funded by the German Federal Ministry for Economic Affairs and Climate Action through the German Federal Ministry of Economics and Climate Protection on the basis of a resolution of the German Bundestag (funding code 22500N) via the Association of Industrial Research Associations “Otto von Guericke” (AiF) and the German Aerospace Center as part of the program for the promotion of industrial joint research (IGF).