Effect pigment useful e.g. in paints, automobile lacquers, printing inks and plastic, comprises platelet-shaped substrate having specific circular shape factor, which is coated with a high refractive index layer having high refractive index

摘要

Effect pigment comprises a platelet-shaped substrate having a circular shape factor (calculated as (circumference) 2>/surface normalized to a circle) of 1.2-2, which is coated with at least one high refractive index layer having a refractive index of >= 1.8. Independent claims are also included for: (1) preparing the effect pigment, comprising grinding the substrate present in the form of larger chunks or coarse flakes, adding the obtained substrate platelets having a diameter of 50-200 mu m to a crushing unit and mixing them with water and/or an organic solvent, mechanically treating the obtained suspension for several hours in the crushing unit and simultaneously carrying out smooth polishing of the surface of the platelets, where the mechanical loading of the substrate platelets are carried out such that it leads to permanent shearing of the substrate platelets for further gentle delamination of the platelets and for smoothing the edges and surfaces of the platelets, and classifying the substrate platelets in several sedimentation steps for a narrow particle size distribution of the platelets; (2) a formulation comprising the above effect pigment; (3) a pigment formulation comprising at least one binder, optionally at least one additive and the effect pigment; and (4) a dry formulation comprising the effect pigment.