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Hanover Fair 2009:
Plasma on difficult plastics and glass
At Surface Technology, part of this year’s Hanover Fair, Plasmatreat demonstrated how plastics and glass surfaces that are poor at undergoing adhesive bonding can be made optimally receptive for subsequent bonding or coating processes.
In two demonstrations it was made clear to the specialist public that the activation and cleaning effect of Openair® plasma is so powerful that even the most difficult materials can be coated, painted or adhesively bonded to one another.
Treatment of glass: As a demonstration of the mode of operation of the plasma a robot arm guides the plasma jet over just a part of a glass surface. The component is then removed and for demonstration purposes sprayed manually with water. The activation effect can be seen immediately: while a homogeneous film of water covers the previously treated area, drops of water have formed over the rest of the area which then drip away from the surface. The explanation is that due to the high level of energy supplied by the plasma the surface energy on the treated part of the glass has increased to over 72 mJ/m². This creates the ideal conditions for good wettability with water. On the untreated remainder of the surface of the material, on the other hand, the surface energy has remained at its initial level of only approximately 30 mJ/m².
The second demonstration was aimed at plastics processors who frequently experience problems in applying print or coatings to plastics, such as polypropylene (PP), due to their very low surface energy. At the Fair the pretreatment of a PP component by the new RD2004 rotary jet integrated into a tampon printing press from the company Tampoprint could be seen. Here also, due to the plasma the surface reached an energy level of over 72 mJ/m², the ideal level for subsequent printing processes. There is no thermal damage to the plastic because typical rises in the temperatures of plastic surfaces during treatment amount to only ∆T < 20 °C.
