Patent No. U.S. 7,763,359 B2
Bunge Fertilizantes S.A., São Paulo Brazil and Universidade Estadual de Campinas, Campinas, Brazil have received a patent for a method of making a coating composition comprised of a binding polymer and an opacifying pigment, the method is comprised of the following steps: forming an opacifying pigment by combining phosphoric acid, aluminum sulfate and sodium hydroxide simultaneously, and allowing the combined materials to react with one another for approximately 30 minutes to form a precipitate; drying the precipitate at a temperature of below approximately 130° C to form amorphous aluminum orthophosphate particles comprised of one or more closed voids per particle, wherein the particles are substantially free of open pores; and combining a volume of the amorphous aluminum orthophosphate with a binding polymer to form the opacifying coating composition.