PHYSICOCHEMICAL ASPECTS OF METAL ADHESION OF WATERBORNE STAIN BLOCKING PRIMERS

Various stains such as wood tannin stains, solvent and water ink stains, and food product stains, are prone to migrate through the organic coatings causing an unpleasant appearance on the coating surface. Waterborne stain blocking primers are used for blocking the stains on the substrates from migrating to the surface of the top coats. The adhesion to metals and other substrates is an important property for waterborne stain blocking primers for use as the versatile multi-purpose primers for interior and exterior applications. However, the approaches in the polymer preparation to enhance the stain blocking properties often do not impart adequate adhesion to metals. This paper focuses discussion on a few physicochemical aspects of enhancing metal adhesion for polymers used in waterborne stain blocking primers. The factors that impact the metal adhesion such as surfactant used in polymer preparation, functional groups on polymers, as well as viscoelastic aspect of polymers are examined