COMPOSITION A BASE D'UN SULFURE DE TERRE RARE PRESENTANT UN GROUPEMENT ORGANIQUE EN SURFACE, SON UTILISATION COMME PIGMENT COLORE NOTAMMENT DANS LES PEINTURES

摘要

The invention relates to a composition which is based on a rare-earth sulfide and to its use as a colored pigment, especially in paints. The composition comprises a support which is based on a rare-earth sulfide and which contains at least one alkaline and/or alkaline-earth element, at least part of which is included in the crystalline network of said sulfide; and a layer which at least partially coats the support and which is based on at least one oxide which may have OH radicals on the surface. The invention is characterized in that the composition has on its surface groups from the deposit on the coated support comprising at least one compound chosen from the following; water-insoluble fatty alcohols, water-insoluble aliphatic amines, silanes comprising an alkoxylated radical, epoxy-functionnalized silazanes or polyorganosiloxanes. The inventive composition is produced according to a method in which the coated support is brought into contact with at least one of the aforementioned compounds, a condensation reaction is carried out on the support and the resulting composition is separated from the reaction medium.