Surface analysis of matt powder coatings

A study of gloss reduction of powder coatings was performed using different waxes, fillers and non-compatible polymer resins (matting hardeners). Coatings with reduced surface smoothness were analysed. Scanning electron micrographs were taken to visualize the surfaces. All of the applied matting additives changed the surface profile of coating. The most interesting surface structural form is provided by wax particles. The average size of these forms was calculated by applying image analysis to some sample micrographs. The surface shape of all of the prepared coatings was analysed using surface profile measurements. Two parameters of these profiles were determined, the average roughness and the mean spacing between the surface peaks. The influence of several physical surface parameters on specular gloss characteristics is discussed.