Sun Chemical patents
yellow pigment
Patent No. U.S. 7,060,835 B2 Sun Chemical Corp. has been granted a patent for a process for preparing transparent Pigment Yellow 138 comprised of grinding Pigment Yellow 138 in the presence of a grinding agent; preparing an aqueous slurry of the ground pigment; and filtering the slurry resulting in a filter cake containing particles of transparent Pigment Yellow 138.