Orientation of talc particles in dispersion coatings

A novel approach was used for the determination of talc particle orientation. X-ray diffraction technique with the peak ratio method was utilized to obtain information on the ratio between misaligned and aligned crystals aligned with the surface. Cross-sections of coatings were studied by scanning electron microscopy. Particle orientation was determined by image analysis. A laser profilometer and a glossmeter were used to obtain additional information about surface properties. The effects of coating thickness, calendering, base sheet roughness, and pigment size distribution on orientation were studied. Both calendering and base sheet roughness affected the orientation of talc particles significantly. In addition, the results indicated that good packing could be achieved with a proper pigment size.