Activation of Plastic Surfaces with Plasma

Activation here means an increase in surface energy, which results in improved adhesion properties and thus wettability. The contact angle of a drop on a plastic is a common measure of adhesion. In many cases, polymers have low surface energies or are hydrophobic, which can cause problems when using water-based paints, for example. So they have to be modified before painting or printing. Plasma has proven to be a very efficient tool for this purpose. Plasma activation is a substitute for conventional adhesion promoters. Furthermore, there are hardly any limits as far as the geometry of the workpieces and the type of polymer are concerned, since the temperature does not rise significantly during the process. In addition, the topography of the plastic remains almost unchanged, only the top monolayers are modified. For activation processes, the plasma typically consists of oxygen, but sometimes nitrogen or ammonia. When oxygen is used, it is possible to modify polymers in such a way that hydroxyl, carboxyl or peroxide groups are formed on the surface. On the other hand, if nitrogen or ammonia is used, this leads to amine or imine groups, which can also be of interest for certain applications. These polar hydrophilic groups improve surface wettability. Activation processes usually only last a few seconds. After activation, the workpieces are prepared for immediate further processing, which may even be possible in the same plasma system.

Very good Adhesion

Better Homogeneity

High process stability