U.S. 8,197,654 B2
PPG Industries has been awarded a patent for a method for preparing an electrodepositable coating comprised of mixing a flatting agent with an electrodepositable resin; combining the mixture with a pigment paste to form a flatting agent-pigment paste mixture; and combining the flatting agent-pigment paste mixture with an electrodepositable resin; the flatting agent is comprised of silica, clay, talc, barite, calcium carbonate, barium sulfate, aluminum silicate, sodium aluminum silicate, hollow spheres of alumina silicate, potassium aluminum silicate, magnesium silicate or combinations thereof.
Source:
http://www.coatingsworld.com/issues/2013-03/view_patents/ppg-patents-method-for-preparing-an-electrodepositable-coating/
