Protective and application properties of self-stratifying pigmented systems

Spontaneously stratifying coatings have been widely studied by many scientists for over two decades. So far, series of epoxy/acrylic resins pairs were investigated, conditions of phase separation and stratification processes were established, parameters having an influence on them, were determined. Far more difficult task is to obtain protective-decorative coating with repeatable, established pigments distribution: colouring one in the top layer and anticorrosive one in the bottom layer, near the substrate. The aim of our work was to investigate protective and application properties of self-stratifying coatings containing epoxy and acrylic resins as well as one of selected colouring pigments (titanium dioxide, chrome oxide green) and barrier anticorrosive pigment. Pigment distribution and properties of coatings were determined depending on conditions of paint preparation, type of paint application and on the type of additives used. It was expressed by coefficient of pigments distribution between the top and the bottom layer. Results of investigations of self-stratifying coatings in salt spray chamber prove that such systems have comparable or better anticorrosive properties in comparison with classical two-layered systems containing the same resins and pigments. Results of investigation show that different types of paint application (especially spraying) require specially selected additives to be used in formulations.