The impact of surface preparation of wood on the adhesion of certain types of coatings

Abstract

In order to achieve an enhancement of adhesion of specific type of coating to the surface of beech wood (Fagus Sylvatica L.), the optimum substrate preparation system was determined regarding the specific coating formulation. The results showed that lower values of surface roughness parameters can be obtained by the sanding process than by the planning process. These lower values of surface roughness enable higher adhesion of a 2K acrylic-isocyanate coating. In cases where coating is performed with a 1K waterborne coating, higher values of adhesion were observed on the surfaces with higher surface roughness. Direct correlation between surface roughness and adhesion of a 2K polyurethane coating was not found. The adhesion between a 1K waterborne coating and the wood substrate is primarily based on a mechanical bonding (entanglement), while the adhesion of a 2K acrylic-isocyanate coating is primarily based on the other bonding mechanisms.