Patent ID: 8759441

Claim:
A pigment dispersion comprising: a color pigment; and a polymeric dispersant including more than one pending chromophore group covalently bonded to a polymeric backbone of the polymeric dispersant through a linking group; wherein the more than one pending chromophore group is a derivative from a color pigment including an aromatic group selected from the group consisting of monoazo pigments, disazo pigments, β-naphtol pigments, naphtol AS pigments, azo pigment lakes, benzimidazolone pigments, disazo condensation pigments, metal complex pigments, isoindolinone pigments, isoindolinine pigments, phthalocyanine pigments, quinacridone pigments, diketopyrrolo-pyrrole pigments, thioindigo pigments, anthraquinone pigments, anthrapyrimidine pigments, indanthrone pigments, flavanthrone pigments, pyranthrone pigments, anthanthrone pigments, isoviolanthrone pigments, aluminium pigment lakes, dioxazine pigments, triarylcarbonium pigments, and quinophthalone pigments; the more than one pending chromophore group is a chromophore group occurring as a side group on the polymeric backbone and not a group in the polymeric backbone itself or occurring solely as an end group of the polymeric backbone; the linking group consists of all the atoms between the polymeric backbone and the first atom of the aromatic group of the pending chromophore group by which the pending chromophore group is linked to the polymeric backbone; the polymeric dispersant has a polymeric backbone with a polymerization degree between 5 and 1,000; at most 30% of the monomer units of the polymeric backbone have a pending chromophore group; and the linking group is selected from the group consisting of an amide group, an ester group, a urethane group, an ether group, and a thioether group.