Adhesion of encapsulating films used in PV module manufacturing

In this study, several surface treatment methods (Corona, Atmospheric Plasma and Saint-Gobain´s proprietary treatment) were explored to understand the effectiveness of each method in creating an ETFE surface more favorable for bonding to Solarbond™ EVA. Surface analyses indicate that all surface treatment technologies evaluated incorporate polar oxygen and nitrogen containing functionalities onto the ETFE surface. However, our study shows that the presence of such polar functionalities on the ETFE surface is not the only factor that is critical to ensure good adhesion strength to Solarbond™ EVA. The existence of a mechanically weak boundary layer on the treated ETFE surface appears to play an equally important role in affecting the adhesion strength to Solarbond™ EVA. We propose that the higher adhesion strength of Solarbond™ EVA to Fluorosol™ ETFE treated with Saint Gobain´s (SG) proprietary treatment can be attributed to the presence of appropriate polar functionalities as well as the mechanically-strong boundary layer created as a result of treatment.