Composition based on a rare-earth metal sulphide comprising at least one alkali metal element its process of preparation and its use as a coloured pigment

摘要

The compsns. are based on a rare earth metal sulphide doped with 1 alkali metal, where the sulphide is in the form of microcrystalline particles with an average size of NOTGREATER 1.5 mu m. Also claimed is: (i) a process for prepn. of a compsn. based on a rare earth metal sulphide doped with 1 alkali metal, comprising contacting a rare earth metal carbonate or hydroxycarbonate with 1 alkali metal cpd. and heating in the presence of H2S and/or CS2; (ii) a coloured pigment comprising 1 compsn. as above; and (iii) coloured materials, esp. plastics, paints, lacquers, rubber, ceramics, glazes, paper, inks, cosmetic prods., dyes (teintures) and laminated coatings, contg. a compsn. or pigment as above.