Many experiments have been performed globally to investigate ways of controlling and improving adhesion of energy curable UV paints, inks and coatings utilized to decorate structural polymers. Automotive plastics with a low polarity, such as PE, PP, TPO, POM, PUR and PTFE typically require surface treatment when value-added decoration is required. Metallic surfaces may also require cleaning to remove low molecular weight organic materials prior to decoration. Once the above-mentioned interior and exterior grades of substrate surfaces are cleaned and activated, printing, gluing and painting are possible without the use of adhesion-promoting primers. There is a class of innovations in three-dimensional surface treating technologies for plastics finishing which address the need to advance adhesion properties of decorating materials, increase product quality, and achieve environmental objectives within the automotive industry. These innovations include advanced thermal and non-thermal discharge treatment processes for raising the polarity of surfaces to be painted, bonded, decorated, laminated, printed, or to have tape applied.
This paper discusses a new class of atmospheric surface activation systems, appropriate measurements of wettability and adhesion, over-treatment effects and surface analysis techniques relative to optimizing the adhesion of digital UV inks, paints, coatings and adhesives to structural polymer surfaces. Recommendations for improved activation by substrate and application are discussed.