Evaluation of effect pigment orientation using combined SEM, TEM, and X-ray CT analysis and conclusion for interpreting goniospectro-photometric data of effect coatings

Abstract

Plate-like effect pigments (with diameters between 5-40μm and less than 1μm thick) are widely used to create decorative appearance in coatings, prints, plastics and cosmetics. Thereby the color and texture do not only depend strongly on type and concentration of the effect pigment, but also on their orientation distribution in the corresponding medium. In order to predict the appearance of a given effect pigment, its orientation distribution obtained using a specific method of application (spray application, roller blade application, offset printing, brushing, etc.) should be measured. This is usually done by preparing mechanical cross sections and obtaining the 2D particle inclination distribution N(d) by semiautomatic image processing of microscope images.