Blue Colored Inorganic Pigments, Having Near Infrared Reflectance, Based on Mixtures of Lanthanum, Strontium, Copper and Lithium Silicate and Process Thereof

Mundlapudi Lakshmipathi Reddy, Sheethu Jose

Nontoxic Near Infrared Reflecting (NIR) inorganic pigments, characteristically blue and well suited for the coloration of a wide variety of substrates, for example, plastics and concrete building roofing material, etc., comprise mixed metal silicate having the general formula: LaxSr1-xCu1-yLiySi4O10, where x is equal to 0 to 0.5 and y is equal to 0 to 0.5. These silicates with tetragonal crystal structure are prepared by calcination method in air atmosphere.