Patent No. U.S. 7,122,081 B2
Ciba Specialty Chemicals Corporation has received a patent for a process for particle size reduction of organic pigments to improve the optical properties of pigments. The process is comprised of milling a mixture comprised of approximately 10% to 60% weight of one or more crude organic pigments, from 0.1% to 25% weight of water soluble styrene copolymer dispersant based on the dry weight of the crude organic pigment, optionally from 0.1% to 1.0% weight of a defoamer, optionally from 0.1% to 5.0% weight of an additive based on the dry weight of the crude organic pigment, and greater than 10% weight water wherein the first, third and fourth weights are based on the total weight of the mixture, and isolating the organic pigment.