PlasmaSolution – Curing of coating formulations using non-thermal plasmas
S Dahle, J Žigon, M Petrič
Coatings are an important part of wood protection, especially for outdoor applications. In order to provide a good protection, protective coatings need to exhibit good adhesion, mechanical resistance, and weathering resistance. Plasma pre-treatments are an established method to increase the performance of existing coatings including those on wood and wood-based substrates. Moreover, plasma deposition is well-known for its generation of very durable coatings, but has hardly been used on wooden substrates before. In this project, we are combining both approaches, using non-thermal plasma discharges for the curing of coatings intended for the protection of wood and wood-based materials in outdoor applications.
Initial results on MMA-based and PDMS-based coatings produced through plasma curing, i.e. plasma-enhanced chemical solution depositions, were very promising, as these were gradient coatings indicating mechanical durability at the surface and higher flexibility within the coating.
During the project, we have developed, tested, and optimized two types of plasma equipment. On one hand, we set up surface barrier discharge devices, which are independent of the substrate material and size, while offering the least disturbance on the formulations surfaces that might otherwise lead to uneven coating characteristics. As surface discharges require a close distance to be effective for these purposes, we also set up conventional dielectric barrier discharge setups, which offer higher treatment intensities, but are more limited as to the size of the work pieces. Both types of equipment have been characterized and utilized on the intended substrates and are now being applied for the curing of the coating formulations.