Mechanism analysis of sheet gloss development by addition of plastic pigment

Effects of the particle size of plastic pigment on sheet gloss and structure of coatings which were constituted of clay/plastic pigment/binder were studied. The most effective particle size for sheet gloss was about 200 nm and the ranking of the size for sheet gloss did not vary before and after supercalendering. In addition, such ranking was not affected by the king of binder coexisted in coating.From structural analysis, it was found that the coating having highest sheet gloss showed highest degree of orientation of clay particles, highest surface smoothness in submicron range, and lowest surface concentration of plastic pigment.Those results indicated that clay/plastic pigment packing manner, which would affect the orientation of clay particles and the surface smoothness, was a dominant factor for sheet gloss development rather than thermoplasticity of plastic pigment.