# US 11,077,692 B2 · Aqueous pigment dispersion > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,077,692 B2 - Document ID: US11077692B2 - Status: Granted - Kind: B2 - Application number: 16/635,098 - Filed: 2018-07-27 - Published: 2020-05-21 - Granted: 2021-08-03 - Earliest claimed: 2017-08-02 - Assignees: Kao Corporation - Applicants: Kao Corporation - Inventors: Takayuki Suzuki; Takako Yamamoto; Erika Maekawa; Yasufumi Ueda - Web page: https://patentgrep.com/patent/US11077692B2 ## CPC - B41M 5/0023: {Digital printing methods characterised by the inks used (inks per se C09D11/00)} - C09D 17/003: {containing an organic pigment (process features in the making of dye stuff preparations C09B67/00)} - B41J 2/01: Ink jet - B41J 2/2107: {characterised by the ink properties (supplying ink in a solid state B41J2/17593)} - C08F 212/08: Styrene - C08F 220/06: Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof - C08F 220/1807: {C7-(meth)acrylate, e.g. heptyl (meth)acrylate or benzyl (meth)acrylate} - C08J 3/07: from polymer solutions - C09C 1/56: Treatment of carbon black {; Purification} - C09C 3/10: Treatment with macromolecular organic compounds {(C09C3/006 takes precedence)} - C09D 11/107: from unsaturated acids or derivatives thereof - C09D 11/322: Pigment inks - C09D 11/324: containing carbon black - C09D 11/326: characterised by the pigment dispersant - C09D 11/38: characterised by non-macromolecular additives other than solvents, pigments or dyes - C09D 17/005: {Carbon black} - C08F 2810/20: leading to a crosslinking, either explicitly or inherently - C08J 2325/14: with unsaturated esters - C08J 2333/02: Homopolymers or copolymers of acids; Metal or ammonium salts thereof - C08J 2333/10: Homopolymers or copolymers of methacrylic acid esters - B41M: PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING, (correction of typographical errors B41J; processes for applying transfer pictures or the like B44C1/16; fluid media for correction of typographical errors by coating C09D10/00; printing textiles D06P) - 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) - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS - C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29) - C09C: TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES (treatment of materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone C04B14/00, C04B18/00, C04B20/00); PREPARATION OF CARBON BLACK {; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS} ## Abstract The present invention relates to a pigment water dispersion containing a pigment, a crosslinked polymer and water, in which the crosslinked polymer is prepared by crosslinking a carboxy group-containing polymer with a crosslinking agent, and has an acid value of not less than 70 mgKOH/g and not more than 300 mgKOH/g; and the pigment water dispersion further contains a formaldehyde-releasing compound. The pigment water dispersion of the present invention is excellent in storage stability even when being stored under high-temperature conditions for a long period of time. ## Claims ### Claim 1 A pigment water dispersion comprising a pigment, a crosslinked polymer and water, in which the crosslinked polymer is prepared by crosslinking a carboxy group-containing polymer with a polyfunctional epoxy compound, and has an acid value of not less than 70 mgKOH/g and not more than 300 mgKOH/g; and the pigment water dispersion further comprises a formaldehyde-releasing compound, wherein the carboxy group-containing polymer is an acrylic polymer, and the formaldehyde-releasing compound is at least one compound selected from the group consisting of 1,3,5-triazine-1,3,5-(2H, 4H, 6H)-tris(ethanol), 1,3 -bis(hydroxymethyl)-5,5-dimethyl hydantoin and cis-1-(3-chloroallyl)-3,5,7-triaza-1-azonia adamantane chloride, wherein a content of water in the pigment water dispersion is not less than 50% by mass and not more than 90% by mass. ### Claim 2 (depends on 1) The pigment water dispersion according to claim 1, wherein a content of the formaldehyde-releasing compound in the pigment water dispersion is not less than 100 ppm and not more than 1500 ppm. ### Claim 3 (depends on 1) The pigment water dispersion according to claim 1, wherein a mass ratio of the formaldehyde-releasing compound to the crosslinked polymer [formaldehyde-releasing compound/crosslinked polymer] in the pigment water dispersion is not less than 0.001 and not more than 0.05. ### Claim 4 (depends on 1) The pigment water dispersion according to claim 1, wherein an epoxy equivalent of the polyfunctional epoxy compound is not less than 100 and not more than 300. ### Claim 5 (depends on 1) The pigment water dispersion according to claim 1, wherein a crosslinking degree of the carboxy group-containing polymer is not less than 5 mol % and not more than 40 mol %. ### Claim 6 (depends on 1) The pigment water dispersion according to claim 1, wherein the pigment and the crosslinked polymer are present in the form of pigment-containing crosslinked polymer particles. ### Claim 7 (depends on 1) The pigment water dispersion according to claim 1, wherein the pigment-containing crosslinked polymer particles are produced by a process comprising the following steps 1 to 3: Step 1: subjecting a mixture comprising a carboxy group-containing water-insoluble polymer, an organic solvent, the pigment and water to dispersion treatment to obtain a dispersion liquid of pigment-containing water-insoluble polymer particles; Step 2: removing the organic solvent from the dispersion liquid obtained in the step 1 to obtain a water dispersion liquid of the pigment-containing water-insoluble polymer particles; and Step 3: subjecting the water-based pigment dispersion liquid obtained in the step 2 to crosslinking treatment with a crosslinking agent to obtain an aqueous pigment dispersion liquid comprising pigment-containing crosslinked water-insoluble polymer particles. ### Claim 8 (depends on 1) The pigment water dispersion according to claim 1, wherein a content of the crosslinked polymer in the pigment water dispersion is not less than 1% by mass and not more than 8% by mass. ### Claim 9 (depends on 1) The pigment water dispersion according to claim 1, wherein the carboxy group-containing polymer is a water-insoluble polymer. ### Claim 10 (depends on 9) The pigment water dispersion according to claim 9, wherein an acid value of the water-insoluble polymer is not less than 90 mgKOH/g and not more than 350 mgKOH/g. ### Claim 11 (depends on 9) The pigment water dispersion according to claim 9, wherein the water-insoluble polymer comprises a constitutional unit derived from (a) a carboxy group-containing vinyl monomer and a constitutional unit derived from (b) a hydrophobic vinyl monomer. ### Claim 12 (depends on 11) The pigment water dispersion according to claim 11, wherein the water-insoluble polymer further comprises at least one constitutional unit selected from the group consisting of a constitutional unit derived from (c) a macromonomer and a constitutional unit derived from (d) a nonionic monomer. ### Claim 13 (depends on 1) The pigment water dispersion according to claim 1, wherein a molecular weight of the polyfunctional epoxy compound is not less than 120 and not more than 2000. ### Claim 14 (depends on 1) The pigment water dispersion according to claim 1, wherein the polyfunctional epoxy compound is at least one compound selected from the group consisting of polypropylene glycol diglycidyl ether, trimethylolpropane polyglycidyl ether and pentaerythritol polyglycidyl ether. ### Claim 15 (depends on 1) The pigment water dispersion according to claim 1, wherein an acid value of the crosslinked polymer is not less than 85 mgKOH/g and not more than 280 mgKOH/g. ### Claim 16 (depends on 1) The pigment water dispersion according to claim 1, wherein a mass ratio of the pigment to the crosslinked polymer (pigment/crosslinked polymer) is not less than 0.8 and not more than 5. ### Claim 17 (depends on 1) A water-based ink for ink-jet printing comprising the pigment water dispersion according to claim 1.