# US 10,370,549 B2 · Cationic modified self-dispersing pigment dispersions and inkjet inks thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,370,549 B2 - Document ID: US10370549B2 - Status: Granted - Kind: B2 - Application number: 15/570,421 - Filed: 2016-04-27 - Published: 2018-06-07 - Granted: 2019-08-06 - Earliest claimed: 2015-04-30 - Assignees: E. I. Du Pont de Nemours and Company - Applicants: E I Du Pont De Nemours and Company - Inventors: Michael Stephen Wolfe; Michael J. Eiseman; Loretta L. Tam; Cullen Kirkpatrick - Web page: https://patentgrep.com/patent/US10370549B2 ## CPC - C09D 11/322: Pigment inks - C09D 11/324: containing carbon black - C09D 11/38: characterised by non-macromolecular additives other than solvents, pigments or dyes - C09D 17/001: {in aqueous medium (C09D17/003, C09D17/004 take precedence)} - C09D 17/003: {containing an organic pigment (process features in the making of dye stuff preparations C09B67/00)} - C09D 17/005: {Carbon black} - C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D) ## Abstract This invention pertains to aqueous inkjet inks containing self-dispersing pigments. The self-dispersing pigments are modified with multivalent cations. ## Claims ### Claim 1 An aqueous pigment dispersion comprising: a self-dispersing pigment having at least one type of hydrophilic functional group bonded onto a surface of the self-dispersing pigment, said at least one type of hydrophilic functional group comprising a carboxyl group; and a multivalent cation selected from the group consisting of Mg2+, Ca2+, Cu2+, Al3+, Fe3+, and mixtures thereof, wherein said multivalent cation is adsorbed onto said self-dispersing pigment via ionic bonds between the multivalent cation and surface acid group on the self-dispersing pigment displacing monovalent cation(s) associating with the carboxyl group on the surface of the self-dispersing pigment, the displaced monovalent cation(s) are removed from the pigment dispersion. ### Claim 2 (depends on 1) The pigment dispersion of claim 1, wherein said multivalent cation is present at a level of at least 2 ppm. ### Claim 3 (depends on 1) The pigment dispersion of claim 1, wherein said multivalent cation is Mg2+. ### Claim 4 (depends on 1) The pigment dispersion of claim 1, wherein said multivalent cation is Cu2+. ### Claim 5 (depends on 1) The pigment dispersion of claim 1, wherein said multivalent cation is Ca2+. ### Claim 6 (depends on 1) The pigment dispersion of claim 1, wherein said multivalent cation is Al3+. ### Claim 7 A process for making an aqueous inkjet ink comprising the step of: (a) preparing an aqueous vehicle; (b) adding the aqueous vehicle to an aqueous pigment dispersion, wherein said pigment dispersion comprising a self-dispersing pigment having at least one type of hydrophilic functional group bonded onto a surface of said self-dispersing pigment, said at least one type of hydrophilic functional group comprising a carboxyl group; and a multivalent cation selected from the group consisting of Mg2+, Ca2+, Cu2+, Al3+, Fe3+, and mixtures thereof, wherein said cation is adsorbed onto said self-dispersing pigment via ionic bonds between the cation and surface acid group on said self-dispersing pigment displacing monovalent cation(s) associating with the carboxyl group on the surface of the self-dispersing pigment; and (c) removing the monovalent cation(s) displaced by the multivalent cation. ### Claim 8 (depends on 7) The process of claim 7, wherein said multivalent cation is present at a level of at least 2 ppm. ### Claim 9 (depends on 7) The process of claim 7, wherein said multivalent cation is Mg2+. ### Claim 10 (depends on 7) The process of claim 7, wherein said multivalent cation is Cu2+. ### Claim 11 (depends on 7) The process of claim 7, wherein said multivalent cation is Ca2+. ### Claim 12 (depends on 7) The process of claim 7, wherein said multivalent cation is Al3+. ### Claim 13 An inkjet ink comprising an aqueous vehicle and an aqueous pigment dispersion, wherein said pigment dispersion comprising a self-dispersing pigment having at least one type of hydrophilic functional group bonded onto a surface of said self-dispersing pigment, said at least one type of hydrophilic functional group comprising a carboxyl group; and a multivalent cation selected from the group consisting of Mg2+, Ca2+, Cu2+, Al3+, Fe3+, and mixtures thereof, wherein said multivalent cation is adsorbed onto said self-dispersing pigment via ionic bonds between the multivalent cation and surface acid group on said self-dispersing pigment displacing monovalent cation(s) associating with the carboxyl group on the surface of the self-dispersing pigment, the displaced monovalent cation(s) are removed from the pigment dispersion. ### Claim 14 (depends on 13) The ink of claim 13, wherein said multivalent cation is present at a level of at least 2 ppm. ### Claim 15 (depends on 13) The ink of claim 13, wherein said multivalent cation is Mg2+. ### Claim 16 (depends on 13) The ink of claim 13, wherein said multivalent cation is Cu2+. ### Claim 17 (depends on 13) The ink of claim 13, wherein said multivalent cation is Ca2+. ### Claim 18 (depends on 13) The ink of claim 13, wherein said multivalent cation is Al3+.