U.S. 8,211,224 B2
Sun Chemical Corp. has been granted a process for making a pearlescent pigment comprised of reducing a metal oxide coated substrate with a hydrogen source in the presence of a particulate noble metal catalyst in a liquid medium.
Source:
http://www.coatingsworld.com/issues/2013-03/view_patents/sun-chemical-patents-multi-color-pearlescent-pigments/
