Influence of the Base Plate Surface and Test Environment on Film Adhesion in Organic Composite Coated Steel Sheets with Anti-Fingerprinted Property

Delamination and blistering behavior at the interface of the base plate and insulating layer were investigated during the hot press process for applying an insulating film to organic composite coated steel sheets with anti-fingerprint properties, which are used for printed curcuit boards. A chromate conversion film on an electrogalvanized coating was found to generate water by a dehydration reaction during the hot press process, which produced ZnO and H2 gas at the surface of the zinc layer and possibly induced delamination at the interface of the chromate film and zinc coating. Deterioration of secondary film adhesion after a humid cabinet test was attributed to rapid volumetric expansion due to the evaporation of water that had penetrated from the atmosphere through the insulating layer.