Adhesion between the substrate and the material applied onto it plays a critical role for adhesive bonding, printing and for coatings such as varnish, metallization, etc. In this case, a number of mechanisms and factors may be responsible for the adhesion, such as the wetting of the substrate, its morphology, polarity, formation of chemical links between the substrate and coating, etc. Minimal contamination on the surface as well as the formation of a so-called weak boundary layer can drastically reduce the adhesion levels.
Numerous methods are used, depending on the "contact partners", to achieve good adhesion, including treatments with solvent based and aqueous solutions, flame treatment and corona treatment. However, these are also subject to numerous restrictions and disadvantages, such as material consumption and environmental contamination in the case of wet treatments, or reproducibility problems in the case of flame treatment or corona. Pretreatment of products before adhesive bonding or coating may take several hours.