Effect pigments based on coated glass flakes

Abstract

The present invention relates to effect pigments based on thin glass flakes and to a method for the production of such pigments. The resulting pigment can be used in any application for which pearlescent pigments have been heretofore used-such as, for example, in plastics, paints, inks, cosmetic formulations, coatings including solvent or waterborne automotive paint systems, powder coatings, inks and agriculture foils.

1 . Effect pigments based on glass flakes with a thickness of ≦1.0 μm characterized in that the glass flakes are coated with one or more layers with a high and/or low refractive index.  
     
     
         2 . Effect pigments according to  claim 1 , characterized in that the softening point of the glass flakes is ≧800° C.  
     
     
         3 . Effect pigments according to  claim 1 , characterized in that the glass flakes are coated with one or more layers of metal oxides, metal suboxides, metal oxyhalides, metal fluorides, metal chalcogenides, metal nitrides, metal sulfides, metal carbides, or mixtures thereof.  
     
     
         4 . Effect pigments according to  claim 3 , characterized in that the metal oxide is TiO 2 , Fe 2 O 3 , TiFe 2 O 5 , Ti suboxides, Fe 3 O 4 , Cr 2 O 3 , Al 2 O 3 , SiO 2 , ZrO 2 , ZnO, SnO 2 , CoO, Co 3 O 4 , VO 2 , V 2 O 3 , Sn(Sb)O 2  or mixtures thereof.  
     
     
         5 . Effect pigments according to  claim 4 , characterized in that the glass flakes are coated with TiO 2 , Fe 2 O 3  or a mixture of TiO 2  and Fe 2 O 3 .  
     
     
         6 . Effect pigments according to  claim 4 , characterized in that the TiO 2  is in the rutile modification.  
     
     
         7 . Effect pigments according to  claim 3 , characterized in that the coatings are metal sulfides selected from sulfides of tin, silver, lanthanum, rare earth metals, chromium, molybdenum, tungsten, iron, cobalt and/or nickel.  
     
     
         8 . Effect pigments according to  claim 1 , characterized in that the glass flakes are coated with one or two layers.  
     
     
         9 . A method of preparing an effect pigment according to  claim 1  which comprises coating of the glass flakes by wet chemical coating, by chemical or physical vapor deposition or electroless plating and optionally calcining the coated glass flakes.  
     
     
         10 . Use of the effect pigments according to  claim 1  in plastics, coatings, powder coatings, paints, inks printing inks, glasses, ceramic products, agriculture foils and in cosmetic formulations.  
     
     
         11 . Use of the effect pigments according to  claim 1  as conductive pigments, as magnetic pigments or as dopants for the laser-marking of papers and plastics.  
     
     
         12 . Formulations containing the effect pigments according to  claim 1.