Surfaces of different materials are cleaned, heated and activated by a plasma treatment in the vacuum and at atmospheric pressure. During this process, the ions, electrons, molecules and radicals contained in the plasma remove dirt particles adhering to the surface by direct pulse transmission, remove foreign layers and systematically generate new chemical groups through chemical reactions. A major target of this surface modification is to increase the surface energy and the chemical activity of the surface as adhesive properties of applied paints and glues can thus be improved, e.g. eliminating the need for bonding agents.

 In industrial practice, plasmas generated by gas discharges are used in different manners today for the targeted change of surface characteristics of metals, glasses and in particular of plastic materials, without influencing the volume properties of these. In particular, it is possible to generate hydrophobic or hydrophilic behaviour and to provide the surfaces with (chemically) functional groups in a defined manner.

This technique has not been used in the past for wooden materials as these were associated with major problems in the technical implementation during formerly used vacuum processes due to their often large dimensions, the sensitivity to heat and the lack of vacuum suitability. By developing the atmospheric pressure-plasma technology and adapting it to the requirements of the wood-processing industry, these difficulties have now been overcome, which makes plasma pre-treatment interesting for wood processors. Considerable effects could be achieved through the development of the (already known) dielectrically obstructed discharge (DOD/corona discharge) that takes place at atmospheric pressure and ambient air: Accelerated absorption and increase in penetration depth of the applied inks, paints, adhesives result in:

• Reduced process times

• Increased adhesive strength resulting in

• Increased break strength of glued wood

• Reduced consumption of glue

• Improved functionality and resistance of conventional wood preservation by application or impregnation

• The option of using completely new woods, materials and material combinations. In some cases, the achieved results are independent of type and humidity content of the wood.