Patent ID: 9187653
Filing Date: 2015-11-17
Classification: C01B,C08K,C09D

Abstract:
1. A method of making a coating composition comprising an opacifying pigment, the steps of: combining phosphoric acid, aluminum sulfate, and sodium hydroxide simultaneously to react for a predetermined amount of time to form an amorphous aluminum phosphate precipitate; drying the precipitate to form amorphous aluminum phosphate powder that is substantially free of open pores; and combining the powder with a binding polymer to form a coating composition comprising a dispersion of the powder in the binding polymer, wherein the powder is an opacifying pigment and exhibits two endothermic peaks in Differential Scanning calorimetry between about 90 degrees to about 250 degrees Celsius, wherein the amorphous aluminum phosphate has a skeletal density that is less than about 2.1 g/cc, wherein the amorphous aluminum phosphate has an average individual particle radius size from about 5 to 80 nanometers, and wherein the coating composition when dried to form a film has a structure characterized by enmeshed binding polymer and amorphous aluminum phosphate.