Sensient Colors LLC has been granted a method of modifying a pigment. The method is comprised of attaching a reactive group X—Y to a surface of a pigment; and subsequently displacing Y with an organic substrate N—S—ZM to form a surface-modified pigment having attached X—N—S—ZM; wherein X is a sulfonyl, phosphoryl, or 1,3,5-triazine group; Y is fluorine, chlorine, bromine or iodine; N is an amine, an imine, a pyridine, or a thiol group; S is substituted or unsubstituted alkyls, aryls, or polymer chains having a molecular weight range from approximately 300-8000; Z is a carboxyl, sulfonyl, phenolic, phosphoryl, ammonium, trimethylammonium, or tributylammonium group; and M is a halide, a negatively charged ion, a proton in salt form, or a cation in salt form.
Source:
http://www.coatingsworld.com/issues/0713/view_patents/sensient-patents-self-dispersed-pigments-/