JP2022043715A - Aqueous colorant dispersion, ink, ink set, and image formation product - Google Patents

Abstract

To provide an aqueous colorant dispersion which does not aggregate filtration property without impairing dispersion stability even when a storage temperature is largely changed.SOLUTION: An aqueous colorant dispersion contains a coating coloring agent (A) and an aqueous medium (C), in which the coating coloring pigment (A) contains coloring agent particles and a resin (B) coating the coloring agent particles, the coloring agent particles contain C.I. pigment red 31 and a pigment other than the C.I. pigment red 31, and the resin (B) is a polymer containing one or more hydrophobic monomer units selected from the group consisting of a (meth)acrylate monomer unit having an alkyl group, an aromatic monomer unit, a heterocycle monomer unit and an α-olefin monomer unit.SELECTED DRAWING: None

Description

The present invention relates to an aqueous colorant dispersion used for ink jet recording inks and the like.

Inkjet recording inks are being shifted to water-based pigment inks, which have excellent water resistance and light resistance, instead of water-based dye inks.

In Patent Document 1, a water-based inkjet magenta ink containing at least two kinds of pigments and water, in which a hue angle ∠H ° defined in the CIELAB color space on a recording medium is 330 ° to 360 °. The two or more kinds of pigments have different crystal structures and do not form a solid solution with each other, and the first pigment among the two or more kinds of pigments has the hue angle ∠H. A water-based inkjet magenta ink, wherein ° is a pigment in the range of 290 ° to 360 °, and the second pigment is a pigment in which the hue angle ∠H ° is in the range of 25 ° to 50 °. Is disclosed.

Further, in Patent Document 2, a magenta ink for inkjet containing at least a pigment, an organic solvent and water, which contains at least two kinds of pigments having different hues as the pigment, and the first pigment is the CIE1976 surface color on a recording medium. The system has a hue angle h of 0 to 25 and a saturation C * of 75 or more, and the second pigment is a pigment having a hue angle h of 220 to 350 and a saturation C * of 50 or more. A magenta ink for inkjet, which is characterized by the above, is disclosed.

Further, in Patent Document 3, a magenta ink for inkjet containing two or more kinds of pigments, a specific water-soluble organic solvent having an ethylene oxide group or a propylene oxide group, a surfactant, and water, and the above two kinds or more. Pigment containing azo pigment, and the content of the azo pigment is 0.5 to 8% by mass in the total amount of magenta ink for inkjet and 35 to 100% by mass in the total amount of magenta ink for inkjet. It has been disclosed.

Japanese Unexamined Patent Publication No. 2017-155092 Japanese Unexamined Patent Publication No. 2017-145416 Japanese Unexamined Patent Publication No. 2019-214717

However, the conventional water-based colorant dispersion has a problem that the dispersion state of the water-based colorant dispersion changes when the storage temperature changes significantly, the storage stability deteriorates, and the filterability deteriorates. In addition, continuous printing of ink for inkjet recording causes problems such as clogging of printer nozzles and printing defects, and problems that the color reproduction area of single color or secondary color (color in which two colors of ink are overcoated) is narrow. ..

An object of the present invention is to provide an aqueous colorant dispersion in which the dispersion stability is not easily impaired even if the storage temperature is significantly changed, and the filterability is not easily deteriorated.

The aqueous colorant dispersion of the present invention contains a coating colorant (A) and an aqueous medium (C).
The coating colorant (A) contains the colorant particles and the resin (B) that coats the colorant particles.
The colorant particles are C.I. I. Pigment Red 31, and C.I. I. Contains pigments other than Pigment Red 31
The resin (B) is selected from the group consisting of a (meth) acrylic acid ester monomer unit having an alkyl group, an aromatic monomer unit, a heterocyclic monomer unit, and an α-olefin monomer unit. It is an aqueous colorant dispersion which is a polymer containing one or more kinds of hydrophobic monomer units.

According to the present invention described above, an aqueous colorant dispersion in which dispersion stability is not easily impaired even when the storage temperature is significantly changed and filterability is not likely to be deteriorated, an ink, an ink set, and an image forming product using the aqueous colorant dispersion. Can be provided.

Definitions of the terms herein. "CI" is a color index number. The "(meth) acrylate" is an acrylate and a methacrylate. The monomer is an ethylenically unsaturated group-containing compound before polymerization, and is also called a monomer. The monomer unit is in a state of being incorporated in the resin after polymerization.

The aqueous colorant dispersion of the present invention contains a coating colorant (A) and an aqueous medium (C).
The coating colorant (A) contains the colorant particles and the resin (B) that coats the colorant particles.
The colorant particles are C.I. I. Pigment Red 31, and C.I. I. Contains pigments other than Pigment Red 31
The resin (B) is selected from the group consisting of a (meth) acrylic acid ester monomer unit having an alkyl group, an aromatic monomer unit, a heterocyclic monomer unit, and an α-olefin monomer unit. It is an aqueous colorant dispersion which is a polymer containing one or more kinds of hydrophobic monomer units.

The aqueous colorant dispersion of the present invention is an aqueous colorant dispersion in which the dispersion stability is not easily impaired even if the storage temperature is significantly changed, and the filterability is not easily deteriorated. The reasons for these are C.I. I. Since Pigment Red 31 has a nitro group at the end of the structure, it has very high hydrophilicity, has a low affinity with the coating resin, and tends to reduce the dispersion stability of the coating colorant. Therefore, C.I. I. C.I., which is less hydrophilic than Pigment Red 31. I. By combining pigments other than Pigment Red 31 to form colorant particles, the hydrophilicity thereof is lowered. Further, by using a polymer containing a hydrophobic monomer unit in the resin (B) that coats the colorant particles, the hydrophobic structure is easily adsorbed on the colorant particles. As a result, the dispersion stability of the coating colorant (A) is improved, so that the dispersion stability of the aqueous colorant composition itself is improved, and surprisingly good filterability is also obtained.

<Coating colorant (A)>
The aqueous dispersion of the present invention contains, as the coating colorant (A), colorant particles and a resin (B) that coats the colorant particles.

[Colorant particles]
The colorant particles include C.I. I. Contains Pigment Red 31. C. I. Since Pigment Red 31 is a bluish magenta pigment, the hue of the magenta color can be adjusted to bluish, and the color reproduction region can be expanded more than before when the ink described later is used. Furthermore, C.I. I. Depending on the combination of pigments other than Pigment Red 31, C.I. I. Since a hue that cannot be obtained only with Pigment Red 31 can be obtained, it is possible to express the magenta color of JAPAN COLOR. JAPAN COLOR is a standard institutionalized by the Japan Printing Industry Machinery Manufacturers Association, and the magenta colors as of April 1, 2014 are solid printing with L * = 46.3 and a * = 76. .1, b * =-2.9, ΔE = ± 5 are specified.

C. I. As the pigment other than Pigment Red 31, one kind or two or more kinds of pigments can be used. Also. C. I. Pigments other than Pigment Red 31 are C.I. I. Pigment Red 31 is preferably a pigment having no nitro group because it reduces the hydrophilicity derived from the nitro group. Further, in order to reproduce the magenta color, a pigment having a hue of red to orange to yellow to purple is preferable.
C. I. Pigments other than Pigment Red 31 are, for example, C.I. I. Pigment Red 3,5,19,22,38,42,43,48: 1,48: 2,48: 3,48: 4,48: 5,49: 1,53: 1,57: 1,57: 2,58: 4,63: 1,81,81: 1,81: 2,81: 3,81: 4,88,104,108,112,122,123,144,146,147,149,166 168,169,170,176,177,178,179,184,185,202,208,216,226,242,254,255,257,269,291;
C. I. Pigment Green 7,26,36,50,58,59,62,63;
C. I. Pigment Blue 1,15,15: 1,15: 2,15: 3,15: 4,15: 6,16,17,17: 1,22,27,28,29,36,60;
C. I. Pigment Orange 13, 16, 20, 34, 36, 38, 43, 62, 64, 71, 73;
C. I. Pigment Yellow 1,3,12,13,14,17,34,35,37,55,74,81,83,93,94,95,97,108,109,110,120,128,129,137, 138,139,150,153,154,155,157,166,167,168,174,180,185,193,213,234;
C. I. Pigment Violet 3,19,23,29,30,37,50,88;
C. I. Pigment Black 7,28,26;
C. I. Pigment White 6, 18, 21, etc.
Among these, since the magenta color reproducibility can be expanded, a pigment having a structure selected from the group consisting of a naphthol structure, a quinacridone structure, a diketopyrrolopyrrole structure, and an azo structure (however, it does not have a naphthol structure). Is preferable. Such pigments are C.I. I. Pigment Red 3,5,19,22,38,42,43,48: 1,48: 2,48: 3,48: 4,48: 5,49: 1,53: 1,57: 1,57: 2,58: 4,63: 1,81,81: 1,81: 2,81: 3,81: 4,88,104,108,112,122,123,144,146,147,149,166 168,169,170,176,177,178,179,184,185,202,208,209,216,226,242,254,255,257,269,291, C.I. I. Pigment Violet 19, C.I. I. Pigment Orange 73 and the like. Among these, C.I. I. Pigment Red 122,150,269, C.I. I. Pigment Violet 19 is preferred.

C. I. Pigment Red 31 and C.I. I. As the mixing ratio of the pigments other than Pigment Red 31, the mass ratio is preferably 1:99 to 99: 1, more preferably 5:95 to 50:50, still more preferably 10:90 to 45:55. By setting the mixing ratio within the above range, the color reproduction region can be expanded more than before.

C. I. Pigment Red 31 and C.I. I. As a method for obtaining colorant particles containing a pigment other than Pigment Red 31, any conventionally known method can be adopted. For example, separately synthesized C.I. I. Pigment Red 31 and C.I. I. A method of mixing a solution of a pigment other than Pigment Red 31, a separately synthesized C.I. I. Pigment Red 31 and C.I. I. A method of filtering, drying, and pulverizing a solution of a pigment other than Pigment Red 31, and then mixing using a powder mixer, a kneader, or the like, C.I. I. Pigment Red 31 and C.I. I. Examples thereof include a method of synthesizing pigments other than Pigment Red 31 simultaneously or sequentially. C. I. Pigment Red 31 and C.I. I. When pigments other than Pigment Red 31 are synthesized simultaneously or sequentially, it is also preferable to synthesize them so as to have a core-shell structure having one pigment in the core portion and the other pigment in the shell portion. Further, on at least one of the core portion and the shell portion, C.I. I. Pigment Red 31 and C.I. I. It is also preferable to synthesize it so as to contain a pigment other than Pigment Red 31. In the present specification, the colorant particles have at least C.I. I. Pigment Red 31 is a pigment containing C.I. I. Pigment Red 31 is preferably a pigment other than Pigment Red 31. However, even when the colorant particles having a core-shell structure are used, the core-shell structure may be destroyed when, for example, a salt milling treatment is performed in a subsequent step.

C. I. Among pigments other than Pigment Red 31, C.I. I. Pigment Red 269 can be adjusted in hue as a bluish magenta pigment, and C.I. I. Pigment Red 150 and C.I. I. Since it has the same partial structure as Pigment Red 31, C.I. I. Pigment Red 150 and C.I. I. It is preferable because it can be synthesized at the same time as Pigment Red 31.

C. I. Pigment Red 150, C.I. I. Pigment Red 31, C.I. I. As a mixing ratio of Pigment Red 269, in terms of mass ratio,
C. I. Pigment Red 150: (CI Pigment Red 31 + CI Pigment Red 269) = 99: 1 to 1:99
C. I. Pigment Red 31: C.I. I. Pigment Red 269 = 99: 1 to 1:99 is preferable.
C. I. Pigment Red 150: (CI Pigment Red 31 + CI Pigment Red 269) = 95: 5-10: 90
C. I. Pigment Red 31: C.I. I. Pigment Red 269 = 95: 5-5: 95 is more preferred.

The colorant particles are C.I. I. Pigment Red 31 and C.I. I. As a colorant other than the pigment other than Pigment Red 31, a dye (for example, a disperse dye, a water-soluble dye, etc.) can be used.
Disperse dyes are, for example, C.I. I. Disperse Red 11,50,53,54,55,55: 1,59,60,65,70,72,73,75,86,88,91,92,93,111,126,127,134,135 , 143,145,146,152,153,154,158,159,164,167: 1,177,181,190,190: 1,204,206,207,221,239,240,258,277,278 , 283,311,323,343,348,356,362;
C. I. Bat Red 41;
C. I. Disperse Green 6: 1,9;
C. I. Disperse Blue 19,26,26: 1,35,55,56,58,60,64,64: 1,72,72: 1,73,81,81: 1,87,91,95,108,113 , 128, 131, 141,143, 145, 148, 154, 158, 165, 165: 1,165: 2,176,183,185,197,198,2011,224,225,257,266,267 , 287,354,358,359,360,365,368;
C. I. Disperse Orange 1,1: 1,5,13,20,25,25:1,29,31: 1,33,49,54,55,56,66,73,76,118,119,163;
C. I. Disperse Yellow 3,5,7,8,23,39,42,51,54,60,64,71,79,82,83,86,93,99,100,119,122,124,126,160 , 184: 1,186,198,199,201,204,224,237;
C. I. Disperse Violet 8,17,23,27,28,29,33,36,57;
C. I. Disperse Brown 2; etc.
Examples of the water-soluble dye include direct dyes, acid dyes, edible dyes, basic dyes, reactive dyes and the like. For example, C.I. I. Direct Red 2,4,9,23,26,31,39,62,63,72,75,76,79,80,81,83,84,89,92,95,111,173,184,207, 211,212,214,218,223,224,225,226,227,232,233,240,241,242,243,247;
C. I. Direct Violet 7,9,47,48,51,66,90,93,94,95,98,100,101;
C. I. Direct Yellow 8,9,11,12,27,28,29,33,35,39,41,44,50,53,58,59,68,86,87,93,95,96,98,100, 106,108,109,110,130,132,142,144,161,163;
C. I. Direct Blue 1,10,15,22,25,55,67,68,71,76,77,78,80,84,86,87,90,98,106,108,109,151,156,158, 159,160,168,189,192,193,194,199,200,201,202,203,207,211,213,214,218,225,229,236,237,244,248,249,251 252,264,270,280,288,289,291;
C. I. Direct Black 9,17,19,22,32,51,56,62,69,77,80,91,94,97,108,112,113,114,117,118,121,122,125,132, 146,154,166,168,173,199
C. I. Acid Red 35,42,52,57,62,80,82,111,114,118,119,127,128,131,143,151,154,158,249,254,257,261,263,266 289,299,301,305,336,337,361,396,397;
C. I. Acid Violet 5,34,43,47,48,90,103,126;
C. I. Acid Yellow 17, 19, 23, 25, 39, 40, 42, 44, 49, 50, 61, 64, 76, 79, 110, 127, 135, 143, 151, 159, 169, 174, 190, 195, 196,197,199,218,219,222,227;
C. I. Acid Blue 9,25,40,41,62,72,76,78,80,82,92,106,112,113,120,127: 1,129,138,143,175,181,205,207, 220,221,230,232,247,258,260,264,271,277,278,279,280,288,290,326
C. I. Acid Black 7,24,29,48,52: 1,172;
C. I. Reactive Red 3,13,17,19,21,22,23,24,29,35,37,40,41,43,45,49,55;
C. I. Reactive Violet 1,3,4,5,6,7,8,9,16,17,22,23,24,26,27,33,34;
C. I. Reactive Yellow 2,3,13,14,15,17,18,23,24,25,26,27,29,35,37,41,42;
C. I. Reactive Blue 2,3,5,8,10,13,14,15,17,18,19,21,25,26,27,28,29,38;
C. I. Reactive Black 4,5,8,14,21,23,26,31,32,34;
C. I. Basic Red 12, 13, 14, 15, 18, 22, 23, 24, 25, 27, 29, 35, 36, 38, 39, 45, 46;
C. I. Basic Violet 1,2,3,7,10,15,16,20,21,25,27,28,35,37,39,40,48;
C. I. Basic Yellow 1,2,4,11,13,14,15,19,21,23,24,25,28,29,32,36,39,40;
C. I. Basic Blue 1,3,5,7,9,22,26,41,45,46,47,54,57,60,62,65,66,69,71;
C. I. Basic Black 8; etc.

The colorant particles can be used alone or in combination of two or more.

<Resin (B)>
The resin (B) is selected from the group consisting of a (meth) acrylic acid ester monomer unit having an alkyl group, an aromatic monomer unit, a heterocyclic monomer unit, and an α-olefin monomer unit. A polymer containing one or more hydrophobic monomer units.

[Hydrophobic monomer unit]
The hydrophobic monomer unit is one selected from the group consisting of a (meth) acrylic acid ester monomer having an alkyl group, an aromatic monomer, a heterocyclic monomer, and an α-olefin monomer. The resin (B) is formed by using the above hydrophobic monomer for polymerization.

Examples of the (meth) acrylic acid ester monomer having an alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, and isobutyl (meth). ) Acrylate, tertiary butyl (meth) acrylate, isoamyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cetyl (meth) acrylate, decyl (meth) acrylate, isodecyl Linear or branched alkyl (meth) acrylic acid esters such as (meth) acrylates, lauryl (meth) acrylates, tridecyl (meth) acrylates, isomythyl (meth) acrylates, stearyl (meth) acrylates, and isostearyl (meth) acrylates. ;
Cyclohexyl (meth) acrylate, tertiary butylcyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentanyloxyethyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) ) Cyclic alkyl (meth) acrylic acid esters such as acrylates and isobornyl (meth) acrylates;
Fluoroalkyl (meth) acrylic acid esters such as trifluoroethyl (meth) acrylate, octafluoropentyl (meth) acrylate, perfluorooctylethyl (meth) acrylate, and tetrafluoropropyl (meth) acrylate;
And so on.
The number of carbon atoms of the alkyl group is preferably 1 to 30, more preferably 3 to 20.

Examples of the aromatic group monomer include benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, paracumylphenoxyethyl (meth) acrylate, and paracumylphenoxypolyethylene glycol (meth) acrylate. And aromatic group-containing (meth) acrylic acid esters such as nonylphenoxy polyethylene glycol (meth) acrylate;
Aromatic group-containing vinyl monomers such as styrene and α-methylstyrene;
And so on.

Heterocyclic group monomers include heterocyclic group-containing (meth) acrylic acid esters such as, for example, tetrahydrofurfuryl (meth) acrylates and 3-methyl-3-oxetanyl (meth) acrylates;
Complexes such as 2-vinylpyridine, 4-vinylpyridine, 1-vinylpiperidin, 2-vinylpiperidin, 2-vinylfuran, 3-vinylfuran, 1-vinylpiperidin, 1-vinyl-2-pyrrolidone, 1-vinylimidazole Ring group-containing vinyl monomer;
And so on.

The α-olefin monomer may be, for example, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-icosene, 1-tetracosene, etc. 1-α-olefins such as triacene;
And so on.

The hydrophobic monomer can be used alone or in combination of two or more.

Among them, α-olefins are C.I. I. Effective adsorption to Pigment Red 31 improves viscosity stability under temperature fluctuation storage, which is preferable.

[Other monomer units]
The other monomer unit constituting the resin (B) is not limited as long as it is a monomer copolymerizable with the above-mentioned hydrophobic monomer. Examples of the other monomer include a hydrophilic group-containing monomer, a vinyl monomer (however, excluding the hydrophobic monomer unit), a cyclic carbonate ester monomer, and the like.
The hydrophilic group-containing monomer is a monomer having a hydrophilic group such as a hydroxyl group, a carboxy group, a sulfoic acid group, and a phosphoric acid group.
Hydroxyl-containing monomers include, for example, 2-hydroxyethyl (meth) acrylate, 2 (or 3) -hydroxypropyl (meth) acrylate, 2 (or 3 or 4) -hydroxybutyl (meth) acrylate and cyclohexanedimethanol mono. Hydroxyalkyl (meth) acrylates such as (meth) acrylates, or (meth) acrylamide-based monomers having a hydroxy group, such as N- (2-hydroxyethyl) (meth) acrylamide, N- (2-hydroxypropyl). N- (hydroxyalkyl) (meth) acrylamide such as (meth) acrylamide, N- (2-hydroxybutyl) (meth) acrylamide, or vinyl ether-based monomers having a hydroxy group, for example, 2-hydroxyethyl vinyl ether, A hydroxyalkyl vinyl ether such as 2- (or 3-) hydroxypropyl vinyl ether, 2- (or 3- or 4-) hydroxybutyl vinyl ether, or an allyl ether-based monomer having a hydroxy group, for example, 2-hydroxyethyl allyl ether. , 2- (or 3-) hydroxypropylallyl ether, hydroxyalkylallyl ether such as 2- (or 3- or 4-) hydroxybutylallyl ether, and further the above hydroxyalkyl (meth) acrylate, N- (hydroxyalkyl). ) (Meta) A hydroxy group-containing monomer such as an ethylenically unsaturated monomer obtained by adding an alkylene oxide and / or a lactone to acrylamide, a hydroxyalkyl vinyl ether or a hydroxyalkyl allyl ether; and the like.

The carboxy group-containing monomer is, for example, an itaconic acid half ester such as (meth) acrylic acid, (meth) acrylic acid dimer, itaconic acid, and itaconic acid monomethyl ester, and a maleic acid half ester such as maleic acid and maleic acid monomethyl ester. , Maleic anhydride, fumaric acid, fumaric acid half ester of fumaric acid monoethyl ester, tetrahydrophthalic acid, tetrahydrophthalic acid half ester of tetrahydrophthalic acid monomethyl ester, crotonic acid, 2- (meth) acryloyloxyethyl phthalate, 2 -(Meta) acryloyloxypropyl phthalate, 2- (meth) acryloyloxyethyl hexahydrophthalate, 2- (meth) acryloyloxypropyl hexhydrophthalate, ethylene oxide-modified succinic acid (meth) acrylate, β-carboxyethyl Examples thereof include (meth) acrylate, ω-carboxypolycaprolactone (meth) acrylate, and carboxy group-containing monomers such as compounds having a betaine structure.

The sulfonic acid group-containing monomer is, for example, vinyl sulfonic acid, p-styrene sulfonic acid, p-styrene sulfonic acid sodium salt, 3- (acryloyloxy) propane-1-sulfonic acid, 3- (acryloyloxy) propane-. 1-Sulfonic acid potassium salt, 2-acrylamide-2-methylpropanesulfonic acid, acrylonitrile-tert-butylsulfonic acid, sulfo group-containing monomers such as compounds having an ethylenically unsaturated double bond with a betaine structure; etc. Can be mentioned.

Examples of the phosphoric acid-containing monomer include vinylphosphonic acid, 2-acryloyloxyethyl acid phosphate; and the like.

The vinyl monomer unit is, for example, vinyl ethers such as ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, and isobutyl vinyl ether;
Alkyleneoxy group-containing allyl monomer monomers such as polyethylene glycol allyl ether, methoxypolyethylene glycol allyl ether, polyethylene glycol polypropylene glycol allyl ether, polypropylene glycol allyl ether, butoxypolyethylene glycol polypropylene glycol allyl ether;
N-substituted (meth) acrylamide monomers such as (meth) acrylamide, dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, diacetone (meth) acrylamide, and acryloyl morpholine. ;
(Meta) Nitrile monomers such as acrylonitrile;
Methoxy (poly) ethylene glycol (meth) acrylate, ethoxy (poly) ethylene glycol (meth) acrylate, 2-ethylhexyl (poly) ethylene glycol acrylate, methoxy (poly) propylene glycol (meth) acrylate, ethoxy (poly) propylene glycol ( An alkyleneoxy group-containing (meth) acrylic acid monomer such as meth) acrylate;
Examples thereof include vinyl acetate and fatty acid vinyl monomers such as vinyl propionate; and the like.

Examples of the cyclic carbonate group-containing monomer include the following monomers.

Other monomers can be used alone or in combination of two or more.

Among other monomers, when the carboxy group-containing monomer is introduced into the resin (B), it prevents the coating colorants (A) from aggregating with each other due to charge repulsion in the aqueous medium (C), and the dispersion stability is improved. It is preferable because it improves. In particular, (maleic) maleic acid and maleic acid half ester have a hydrophobic group of C.I. I. It is preferable because it is effectively adsorbed on Pigment Red 31 and dispersion stability is obtained by charge repulsion due to the carboxy group. It is known that maleic anhydride progresses hydrolysis very easily in water to become maleic acid (the half-life of hydrolysis in water at 25 ° C. and pH 7 is said to be about 22 seconds). ..

Further, when an alkyleneoxy group-containing (meth) acrylic acid ester unit or an alkyleneoxy group-containing allyl monomer monomer is introduced into the resin (B), the solubility in an aqueous medium is adjusted by the carbon chain length of the alkyleneoxy group. It is preferable because it can be used and the compatibility with the additives described later is improved.

Examples of the resin having an α-olefin unit and a carboxy group-containing monomer unit include commercially available resins such as Diacarna 30M (manufactured by Mitsubishi Chemical Corporation) and Ceramer series (manufactured by Baker Petrolite).

When the resin (B) has an acid anhydride group such as maleic anhydride or a carboxy group, it is also preferable to introduce a functional group into the resin (B) by reacting with an alcohol. For the reaction, it is necessary to select appropriate reaction conditions such as carrying out the reaction in the presence of a basic catalyst such as diazabicycloundecene.

Examples of the alcohol include methanol, ethanol, propanol, butanol, pentanol, hexanol, decanol and structural isomers thereof, alcohol ethoxylate, alcohol propioxyate, cyclic carbonate group-containing alcohol and the like.

Examples of the cyclic carbonate group-containing alcohol include the following compounds.

Alcohol can be used alone or in combination of two or more.

As the polymerization method of the resin (B), any conventionally known polymerization method such as random polymerization, block polymerization, living radical polymerization, and alternate copolymerization can be adopted.

The content of the hydrophobic monomer unit in the polymer of the resin (B) is preferably 1 to 99 mol%, more preferably 20 to 80 mol% in all the monomer units.

When the resin (B) contains a monomer unit having an acid group such as a carboxy group-containing monomer unit, the acid value is preferably 1 to 350 mgKOH / g, more preferably 50 to 250 mgKOH / g, and 100 to 100. 170 mgKOH / g is more preferable. By setting the acid value in the above range, sufficient dispersion stability can be obtained due to charge repulsion.

The number average molecular weight (Mn) of the resin (B) is preferably 1,000 to 100,000, more preferably 5,000 to 50,000, and even more preferably 7,000 to 30,000. The polydispersity (Mw / Mn) obtained by dividing the weight average molecular weight (Mw) by the number average molecular weight (Mn) is preferably 3.0 or less, more preferably 2.0 or less, still more preferably 1.5 or less. , 1.2 or less is most preferable.

The resin (B) is preferably a resin having a melting point. The melting point of the resin (B) is preferably less than 100 ° C. More preferably, it is 90 ° C. or lower. More preferably, it is 80 ° C. or lower. If the temperature is 100 ° C. or higher, it may be necessary to disperse at a high temperature when dispersing in an aqueous medium, and water may evaporate violently, making it difficult to prepare a dispersion.

The coating amount of the resin (B) is preferably 1 to 200 parts by mass, more preferably 10 to 100 parts by mass with respect to 100 parts by mass of the colorant particles. The resin (B) covers a part or all of the colorant particles to the extent that the problem can be solved in the present application.

<Water-based medium (C)>
Examples of the aqueous medium (C) include water and a water-soluble organic solvent miscible with water.
Water-soluble organic solvents include, for example, polyhydric alcohols, polyhydric alcohol alkyl ethers, polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, sulfur-containing compounds, propylene carbonate, ethylene carbonate, and the like. Other examples include water-soluble solvents.

[water]
The water may be ordinary tap water, but ion-exchanged water, distilled water, and purified water are preferable. The total amount of metal ions contained in water is preferably 10 ppm or less, more preferably 1 ppm or less, and even more preferably 100 ppb or less. In particular, divalent metal ions such as calcium and magnesium crosslink with two acid groups in the resin (B), so it is preferable to suppress them as much as possible. As a result, the ink jet recording ink using the water-based colorant dispersion is less likely to cause nozzle clogging.

[Water-soluble organic solvent]
Examples of polyhydric alcohols include glycerin, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, 1,2-propanediol, 1,3-propanediol, propylene glycol, dipropylene glycol, and tripropylene glycol. , Polypropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5- Pentandiol, 1,2-hexanediol, 1,3-hexanediol, 1,4-hexanediol, 1,5-hexanediol, 1,6-hexanediol, 3-methyl-1,3-butanediol, tri Methylolethane, trimethylolpropane, 1,2,6-hexanetriol, 1,2,4-butanetriol, 1,2,3-butanetriol, petriol, 2-ethyl-2-methyl-1,3-propane Diol, 3,3-dimethyl-1,2-butanediol, 2,2-diethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4-dimethyl-2 , 4-Pentanediol, 2,5-dimethyl-2,5-hexanediol, 5-hexene-1,2-diol, 2-ethyl-1,3-hexanediol and the like.

Examples of the polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, and propylene glycol monobutyl ether. And so on.

Examples of the polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, tetraethylene glycol chlorophenyl ether, ethylene glycol monobenzyl ether, and ethylene glycol monoallyl ether.

Examples of the nitrogen-containing heterocyclic compound include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, ε-caprolactam, γ-butyrolactone and the like. Will be.

Examples of the amides include formamide, N-methylformamide, N, N-dimethylformamide and the like.

Examples of amines include monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, triethylamine, and the like.

Examples of sulfur-containing compounds include dimethyl sulfoxide, sulfolane, thiodiethanol, and the like.

As the other water-soluble solvent, sugar is preferable. Examples of saccharides include monosaccharides, disaccharides, oligosaccharides (including trisaccharides and tetrasaccharides), polysaccharides and the like. Specific examples thereof include glucose, mannose, fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose, lactose, sucrose, trehalose, maltotriose and the like. The polysaccharide means a sugar in a broad sense, and includes substances widely present in nature such as α-cyclodextrin and cellulose. Derivatives of these saccharides are saccharide reducing sugars (eg, sugar alcohols [general formula: HOCH ₂ (CHOH) nCH ₂ OH (where represented by an integer of n = 2-5)], oxidation. Examples thereof include sugars (for example, aldonic acid, uronic acid, etc.), amino acids, thioic acids, and the like. Among these, sugar alcohols are preferable, and martitol and sorbit are more preferable.

Among these, glycerin, ethylene glycol, propylene glycol, diethylene glycol monobutyl ether, 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,2-propanediol, 1, 2-butanediol, 1,3-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol and 1,2-heptandiol are preferred.

The water-based medium (C) can be used alone or in combination of two or more.

<Crosslinking agent (D)>
The aqueous colorant dispersion of the present invention preferably contains a cross-linking agent (D). When the resin (B) has a functional group capable of reacting with the cross-linking agent (D), the inclusion of the cross-linking agent (D) may cause C.I. I. Pigment Red 31 and C.I. I. The cross-linking reaction proceeds with the resin (B) coated on the surface of the colorant particles other than Pigment Red 31, and a strong three-dimensional structure is formed, which improves the viscosity stability even in a harsh environment where the temperature fluctuates. When used in ink jet recording ink applications, ejection stability is improved.

As the cross-linking agent (D), any conventionally known cross-linking agent can be used, for example, epoxy group, oxetanyl group, isocyanate group, ammonia, amino group, quaternary ammonium salt, thiol group, aziridinyl group, carbodiimide group, oxazoline. Examples thereof include compounds having a group and the like. In particular, when the resin (B) has a carboxy group, by adding a compound having a bifunctional or higher functional group in one molecule, it reacts with the carboxy group in the resin (B) to form a strong three-dimensional structure. Therefore, it is preferable. When the resin (B) has a cyclic carbonate ester group, a compound having one or more functional groups selected from ammonia, an amino group and a quaternary ammonium salt can be added to the resin (B). It is preferable because it reacts with the cyclic carbonate group to form a strong three-dimensional structure. The weight average molecular weight or formula weight of the cross-linking agent is preferably 100 to 2,000, more preferably 120 to 1,500, still more preferably 150 to 1,000.

The amount of the cross-linking agent (D) added is preferably 0.2 to 1.5 equivalents, more preferably 0.5 to 1.2 equivalents, relative to the number of moles of acid groups in the resin (B). It is preferable to set the addition amount of the cross-linking agent (D) within the above range because a stronger three-dimensional structure can be formed.

Examples of the epoxy group-containing compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerin triglycidyl ether, glycerol polyglycidyl ether, polyglycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, and sorbitol. Examples thereof include polyglycidyl ethers such as polyglycidyl ether, pentaerythritol polyglycidyl ether, resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, diglycidyl orthophthalate, and hydrogenated bisphenol A type diglycidyl ether.

The oxetanyl group-containing compound is, for example, 4,4'-(3-ethyloxetane-3-ylmethyloxymethyl) biphenyl (OXBP), 3-ethyl-3-hydroxymethyloxetane (EHO), 1,4-bis [ {(3-Ethyl-3-oxetanyl) methoxy} methyl] benzene (XDO), di [1-ethyl (3-oxetanyl)] methyl ether (DOX), di [1-ethyl (3-oxetanyl)] methyl ether ( DOE), 1,6-bis [(3-ethyl-3-oxetanyl) methoxy] hexane (HDB), 9,9-bis [2-methyl-4- {2- (3-oxetanyl)} butoxyphenyl] fluorene , 9,9-Bis [4- [2- {2- (3-oxetanyl)} butoxy] ethoxyphenyl] fluorene and the like.

The isocyanate group-containing compound is, for example, an organic polyisocyanate or an isocyanate group-terminated prepolymer, and the organic polyisocyanate is an aliphatic diisocyanate such as hexamethylene diisocyanate or 2,2,4-trimethylhexamethylene diisocyanate; tolylen-2,4-. Aromatic diisocyanates such as diisocyanate and phenylenediocyanate; alicyclic diisocyanates; aromatic triisocyanates; modified products such as urethane modified products thereof and the like can be mentioned.
The isocyanate group-terminated prepolymer can be obtained by reacting an organic polyisocyanate or a modified product thereof with a low molecular weight polyol or the like. The isocyanate group-containing compound is preferably a compound having three isocyanate groups.
In addition, compounds that generate isocyanate groups by pretreatment such as heat treatment, light treatment, acid treatment, and base treatment, as typified by blocked isocyanate compounds, can also be mentioned.

The amino group, quaternary ammonium salt-containing compound is, for example, a diamine such as hydrazide, carbodihydrazide, thiocarbohydrazide, oxalyldihydrazide;
Ethylenediamine, 1,3-propanediamine, 1,2-propanediamine, 1,4-butanediamine, 1,6-hexamethylenediamine, 1,8-octamethylenediamine, 1,11-diaminoundecane, 1,12- Diaminododecane, 2-butyl-2-ethyl-1,5-pentanediamine, 1,5-diamino-2-methylpentane, 2,2-dimethyl-1,3-propanediamine, 2,4,4-trimethyl- 1,6-diaminohexane, laurylpropylenediamine, ethyleneglycolbis (2-aminoethyl) ether, 1,4-butanediolbis (3-aminopropyl) ether, 1,13-diamino-4,7,10-trio Xatridecane, polyoxypropylenediamine, methanetriamine, 1,2,3-propanetriamine, 1,8-diamino-4-aminomethyloctane, 3- (2-aminoethyl) pentane-1,5-diamine, 1 , 4,7-Triaminocyclononan-1,4,7-triid, butane-1,1,4,4-tetraamine, 2,4-dimethyl-4-ethylamino-2,3,5-triaminohexane , 2,3-bis (diaminomethyl) butane-1,1,4,4-tetraamine, 1,2-bis (methylamino) ethane, 2,5-diamino-2,5-dimethylhexane, butane-1, 1,4-trimethylamine, butane-1,1,4,4-tetramethylamine, 1,2-bis (dimethylamino) ethane, butane-1,1,4-tridimethylamine, butane-1,1,4 , 4-Tetradimethylamine, Hexamethylenetetramine, Diethylenetriamine, Dipropylenetriamine, Bishexamethylenetriamine, Triethylenetetraamine, Adipic acid dihydrazide, Succinic acid dihydrazide, Sebasic acid dihydrazide, Eikosandiic acid dihydrazide, Valindihydrazide, Tetraethylenepenta Min, 3,3'-diamino-N-methyldipropylamine, tris (2-aminoethyl) amine, tris (4-aminoethyl) amine, 3,3'-diamino-N-methyldipropylamine, tris ( An alkylenediamine such as 2-aminoethyl) amine, tris (4-aminoethyl) amine, 1-methylamino-2-dimethylaminoethane, straight chain polyethyleneimine, branched chain polyethyleneimine;
1,2-Cyclohexanediamine, 1,4-Cyclohexanediamine, Isophoronediamine, 1,3-bis (aminomethyl) cyclohexane, 3 (4), 8 (9) -bis (aminomethyl) tricyclo [5.2.1. .0 (2,6)] Decane (TCDdiamine), isopropyl-2,4-diaminocyclohexane, isopropyl-2,6-diaminocyclohexane, 4,4'-methylenebis (cyclohexylamine), 4,4'-methylenebis ( 2-Methylcyclohexylamine), adamantan-1,3-diamine, cyclohexane-1,3,5-triamine, 2,3,5-triaminobicyclo [2,2,1] heptane, piperazine, 2,5-dimethyl Alicyclic diamines such as piperazine, N-cyclohexyl-1,3-propanediamine;
o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,4-toluenediamine, 2,6-toluenediamine, 2,2'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'- Diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfone, xylylenediamine, tris (4-aminophenyl) methane, 1,2,4-benzenetriamine, melamine, benzene-1,2,4,5-tetraamine, pyrimidine- Aromatic ring diamines such as 2,4,5,6-tetraamine, 3,3'-diaminobenzidine, tetraaminophthalocyanine, isophthalic acid dihydrazide;
Examples include quaternary ammonium salt-containing compounds such as butane-1,4-bisammonium chloride.

Examples of the thiol group-containing compound include methanethiol, ethanethiol, thiophenol and the like.

Examples of the aziridine group-containing compound include N, N'-diphenylmethane-4,4'-bis (1-aziridinecarbokisite), N, N'-toluene-2,4-bis (1-aziridinecarbokisite), and bis. Isophthaloyl-1- (2-methylaziridine), tri-1-aziridinylphosphine oxide, N, N'-hexamethylene-1,6-bis (1-aziridinecarbokisite), 2,2'-bis Hydroxymethylbutanol-Tris [3- (1-aziridinyl) propionate], Trimethylol propantri-β-aziridinyl propionate, Tetramethylol methanetri-β-aziridinyl propionate, Tris-2,4 Examples thereof include 6- (1-aziridinyl) -1,3,5-triazine, 4,4'-bis (ethyleneiminocarbonylamino) diphenylmethane and the like.

Examples of the carbodiimide group-containing compound include high-molecular-weight polycarbodiimide produced by decarboxylating a diisocyanate compound in the presence of a carbodiimideization catalyst. Examples of commercially available high molecular weight polycarbodiimides include the carbodilite series manufactured by Nisshinbo.

The oxazoline group-containing compound is, for example, a compound in which two or more, preferably 2 to 3 oxazoline groups are bonded to an aliphatic group or an aromatic group, 2,2-bis (2-oxazoline), 1,3-phenylene. Examples thereof include bisoxazoline compounds such as bisoxazoline and 1,3-benzobisoxazoline, and terminal oxazoline group-containing compounds obtained by reacting the compound with a polybasic carboxylic acid.

Among these, epoxy group-containing compounds are preferable, such as ethylene glycol diglycidyl ether, trimethylolpropane polyglycidyl ether, glycerol polyglycidyl ether, polyglycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, diglycidyl orthophthalate, and sorbitol polyglycidyl ether. , Resolsinol diglycidyl ether, hydrogenated bisphenol A type diglycidyl ether are preferable, and trimethylolpropane polyglycidyl ether is more preferable. The cross-linking agent (D) is preferably appropriately dissolved in the aqueous medium (C) from the viewpoint of cross-linking efficiency. When the cross-linking agent is dissolved in 100 g of water at 25 ° C., the solubility is preferably 0.1 to 50 g, more preferably 0.2 to 40 g, and even more preferably 0.5 to 30 g. Examples of commercially available products include the Denacol series manufactured by Nagase ChemteX.

The cross-linking agent (D) can be used alone or in combination of two or more.

<Manufacturing of water-based colorant dispersion>
The production of the aqueous colorant dispersion preferably has the following steps.
Step I: C.I. I. Pigment Red 31 and C.I. I. Step II of obtaining colorant particles containing pigments other than Pigment Red 31 Step II: Resin (B) was obtained from C.I. I. Pigment Red 31 and C.I. I. Step III: A step of mixing the coating colorant and the aqueous medium (C) by coating the surface of the colorant particles containing a pigment other than Pigment Red 31 to obtain the coating colorant (A).

[Step I: C.I. I. Pigment Red 31 and C.I. I. Step to obtain colorant particles containing pigments other than Pigment Red 31]
C. I. Pigment Red 31 and C.I. I. The step of obtaining the colorant particles containing a pigment other than Pigment Red 31 is not particularly limited, and examples thereof include the following methods.
(1) Separately synthesized C.I. I. Pigment Red 31 and C.I. I. A method of mixing a solution of a pigment other than Pigment Red 31,
(2) Separately synthesized C.I. I. Pigment Red 31 and C.I. I. A method of filtering and drying a solution of a pigment other than Pigment Red 31, and then mixing the mixture.
(3) C.I. I. Pigment Red 31 and C.I. I. A method for synthesizing pigments other than Pigment Red 31 simultaneously or sequentially.

C. I. The method for synthesizing Pigment Red 31 is not particularly limited, but for example, hydrochloric acid and sodium nitrite are added to the compound represented by the following general formula (1) to diazotize, and the compound is represented by the following general formula (2). It is obtained by adding the compound to be reacted and reacting.

C. I. The method for synthesizing the pigment other than Pigment Red 31 is not particularly limited, and any conventionally known synthesis method can be adopted.

(1) Separately synthesized C.I. I. Pigment Red 31 and C.I. I. The method for mixing the solution of the pigment other than Pigment Red 31 is not particularly limited, and any conventionally known method can be adopted. For example, in a stirring tank equipped with a stirring blade, C.I. I. Pigment Red 31 and C.I. I. Examples thereof include a method of adding a solution of a pigment other than Pigment Red 31 and stirring the mixture. C. I. Pigment Red 31 and C.I. I. Pigments other than Pigment Red 31 may be dissolved or suspended in the solution.

(2) Separately synthesized C.I. I. Pigment Red 31 and C.I. I. The method of filtering and drying a solution of a pigment other than Pigment Red 31 and then mixing the mixture is not particularly limited, and any conventionally known method can be adopted. For example, C.I. after drying. I. Pigment Red 31 and C.I. I. Pigments other than Pigment Red 31 were put into a crusher such as Hammer Mill H manufactured by Hosokawa Micron Co., Ltd., and C.I. I. Pigment Red 31 and C.I. I. A method of simultaneously crushing and mixing pigments other than Pigment Red 31, or separately crushed C.I. I. Pigment Red 31 and C.I. I. Examples thereof include a method in which pigments other than Pigment Red 31 are put into a powder mixer such as a Nauter mixer manufactured by Hosokawa Micron Co., Ltd., and uniformly stirred and mixed.

(3) C.I. I. Pigment Red 31 and C.I. I. The method for simultaneously or sequentially synthesizing pigments other than Pigment Red 31 is not particularly limited, but for example, hydrochloric acid and sodium nitrite are added to the compound represented by the general formula (1) to diazotize the compound, and the general formula is used. By adding the compound represented by (2) and the following general formula (3) and reacting, C.I. I. Pigment Red 31 and C.I. I. Examples include a method for obtaining a mixture of Pigment Red 150.

General formula (3)

C. I. Pigment Red 31 and C.I. I. When pigments other than Pigment Red 31 are synthesized simultaneously or sequentially, it is also preferable to synthesize them by a conventionally known production method so as to have a core-shell structure having one pigment in the core portion and the other pigment in the shell portion. For example, C.I. I. Pigment Red 31 was synthesized, followed by C.I. I. By sequential synthesis to synthesize pigments other than Pigment Red 31, C.I. I. Pigment Red 31, C.I. on the shell. I. A pigment having a core-shell structure having a pigment other than Pigment Red 31 can be synthesized. Further, on at least one of the core portion and the shell portion, C.I. I. Pigment Red 31 and C.I. I. It is also preferable to synthesize it so as to contain a pigment other than Pigment Red 31. In the present specification, the colorant particles have at least C.I. I. Pigment Red 31 is a pigment containing C.I. I. Pigment Red 31 is preferably a pigment other than Pigment Red 31.

[Step II: Resin (B), C.I. I. Pigment Red 31 and C.I. I. Step of coating the surface of colorant particles containing a pigment other than Pigment Red 31 to obtain a coating colorant (A)]
The resin (B) was changed to C.I. I. Pigment Red 31 and C.I. I. As a step of coating the surface of the colorant particles containing a pigment other than Pigment Red 31, a conventionally known production method can be adopted, and among them, a salt capable of firmly coating the resin (B) with the colorant. The milling method is preferred.

[Salt milling method]
The salt milling method preferably has the following steps.
Step II-1: C.I. I. Pigment Red 31 and C.I. I. Step of adding at least a water-soluble inorganic salt and a water-soluble organic solvent to the colorant particles and the resin (B) containing a pigment other than Pigment Red 31 and grinding and kneading Step II-2: Water-soluble inorganic salt and water-soluble organic solvent Step to remove

The above-mentioned production method is particularly effective when the colorant is an organic pigment. It may also be applied to dye particles.

First, a step of mixing the colorant, the resin (B), the water-soluble inorganic salt and the water-soluble organic solvent with a kneader (salt milling treatment) is performed (step II-1), and the water-soluble inorganic salt and the water-soluble organic solvent are mixed. It is preferable to perform a step of washing and removing (cleaning treatment) (step II-2).

The salt milling treatment is a batch of a mixture of a colorant, a water-soluble inorganic salt and a water-soluble organic solvent, for example, a kneader, a 2-roll mill, a 3-roll mill, a ball mill, an attritor, a sand mill, or a planetary mixer. This is a treatment in which a water-soluble inorganic salt and a water-soluble organic solvent are removed by washing with water after mechanically kneading while heating using a formula or continuous kneader. The water-soluble inorganic salt acts as a crushing aid, and the water-soluble organic solvent acts as a particle growth agent. During salt milling, the primary particles of the colorant are crushed by utilizing the high hardness of the inorganic salt. In addition, the colorant grows primary particles when it comes into contact with a water-soluble organic solvent. By optimizing the conditions for salt milling the colorant, this crushing and growth is repeated, the primary particle size is very fine, the distribution width is narrow, and the coloring has a sharp particle size distribution. You can get the agent. Further, since the primary particle shape is also uniformly crushed and grown from all directions of the primary particle, the primary particle shape is not flat and the primary particle close to a true sphere can be obtained.

The kneading temperature at the time of salt milling is preferably −10 ° C. to 300 ° C., more preferably 30 ° C. to 90 ° C. By performing salt milling at an appropriate temperature, the primary particles of the colorant are made finer, and the resin (B) can coat the colorant particles.

The kneading time for salt milling is preferably 0.1 to 100 hours, more preferably 3 to 24 hours. By performing salt milling at an appropriate kneading time, the primary particles of the colorant are made finer, and the resin (B) can coat the colorant particles.

[Water-soluble inorganic salt]
Examples of the water-soluble inorganic salt include sodium chloride, barium chloride, potassium chloride, sodium sulfate and the like. Sodium chloride (salt) is preferable from the viewpoint of price. The amount of the water-soluble inorganic salt (X) used is preferably 50 to 2,000 parts by mass, more preferably 300 to 1,000 parts by mass with respect to 100 parts by mass of the colorant, from the viewpoints of both treatment efficiency and production efficiency. The particle size of the water-soluble inorganic salt is preferably 0.001 to 100 μm, more preferably 0.1 to 10 μm.

[Water-soluble organic solvent]
As the water-soluble organic solvent, the polyhydric alcohols described above are preferable. The amount of the water-soluble organic solvent used is preferably 5 to 1,000 parts by mass, more preferably 50 to 500 parts by mass with respect to 100 parts by mass of the colorant. By appropriately selecting the amount of the water-soluble organic solvent used, the kneaded product can have a viscosity suitable for the salt milling treatment.

In the washing treatment, a mixture containing a colorant, a resin (B), a water-soluble inorganic salt, and a water-soluble organic solvent is taken out from a grinding and kneading machine, a solvent is added, and the mixture is stirred to obtain a suspension. The type of solvent to be added is not particularly limited as long as it can dissolve the water-soluble inorganic salt and the water-soluble organic solvent, but tap water, an acid aqueous solution such as a hydrochloric acid aqueous solution, and ion-exchanged water are preferable. The amount of the solvent to be added is not particularly limited as long as it is sufficient to obtain a suspension. For example, a solvent having a weight of 10 to 10,000 times is added and mixed and stirred. It may be heated if necessary. The mixing and stirring conditions at this time are not particularly limited, but it is preferably performed at a temperature of 5 to 100 ° C. Subsequently, by removing the filtrate by an operation such as filtration, the water-soluble inorganic salt and the water-soluble organic solvent used in the kneader can be removed, and the coating colorant containing the colorant particles and the resin (B) can be removed. (A) can be obtained.

After the cleaning treatment, a step of removing the solvent may be performed. Suitable methods include, for example, a method of performing a drying treatment. Examples of the drying conditions include a method of drying under normal pressure in the range of 80 to 120 ° C. for about 12 to 48 hours, a method of drying under reduced pressure in the range of 25 to 80 ° C. for about 12 to 60 hours, and the like. Be done. The drying process is not particularly limited, but a method using a spray drying device can also be mentioned. The pulverization treatment may be performed at the same time as the drying treatment or after the drying treatment.

As the average primary particle size of the colorant, the average primary particle size of the colorant before salt milling is preferably about 10 nm to 10,000 nm, and the average primary particle size of the colorant after salt milling is preferably about 5 nm to 200 nm. It is preferable that the average primary particle size of the colorant before salt milling> the average primary particle size of the colorant after salt milling. It is preferable that the average primary particle size is reduced because the coloring power and transparency are improved. The average primary particle size can be obtained by arithmetically averaging the major axis of the primary particles of 100 primary particles of the colorant extracted from a plurality of photographs taken with a transmission electron microscope at a magnification of 10,000 times. ..

Next, a step of adding the aqueous medium (C) to the coating colorant (A) after the cleaning treatment and mixing while heating or cooling as necessary is performed (step III). As the mixing method, a conventionally known method can be adopted, for example, a high-speed mixer, a homogenizer, a high-pressure homogenizer, a planetary mixer, a trimix, a kneader, an oscillator, a horizontal sand mill, a vertical sand mill and / and an anura type bead mill, and a paint. Examples thereof include a shaker, a ball mill, a disperser equipped with an ultrasonic oscillator, a high-pressure disperser, a counter-collision type disperser, a diagonal collision type disperser, a two-roll mill, and a three-roll mill. By these steps, the agglomeration of the colorant particles is crushed to the level of the primary particles, and an aqueous colorant dispersion can be prepared.

In step III, a basic compound described later can be added. It is particularly preferable when the resin (B) has an acid group-containing monomer unit such as a carboxy group or a phosphoric acid group. It is preferable to add a basic compound because the acid group is neutralized and the dispersion system is stabilized by charge repulsion. In addition, it may be possible to cause reactivity with the cross-linking agent (D) described later. The basic compound is preferably added in an amount of 0.1 to 2.0 equivalents to the acid group, and more preferably 0.4 to 1.5 equivalents.

In step III, the above-mentioned cross-linking agent (D) can be added. When the resin (B) has a functional group capable of reacting with the cross-linking agent (D), the cross-linking reaction forms a strong three-dimensional structure on the surface of the colorant particles, so that the viscosity is high even in a harsh environment where the temperature fluctuates. This is preferable because the stability is improved and the ejection stability when the ink is used for inkjet recording is improved. The temperature at which the cross-linking agent (D) is added can be arbitrarily selected depending on the reactivity of the cross-linking agent. For example, a method of adding and stirring the cross-linking agent (D) below the reaction temperature of the cross-linking agent (D) and the resin (B) and then raising the temperature above the reaction temperature, the cross-linking agent (D) and the resin (B) Examples thereof include a method of adding the cross-linking agent (D) at a temperature higher than the reaction temperature of.

After completion of the reaction, the pH can be adjusted to the desired pH with any acid or a basic compound described later, if necessary. Specific examples of the acid include inorganic acids such as phosphoric acid, hydrochloric acid, sulfuric acid and nitric acid, and organic acids such as acetic acid and citric acid. Further, an aqueous medium (D) may be added to adjust the non-volatile content.

The pH of the water-based colorant dispersion after pH adjustment is preferably 7 to 10, more preferably 8 to 10, and even more preferably 8 to 9.5.

The obtained aqueous colorant dispersion is preferably filtered or centrifuged. Coarse particles can be removed by filtering or centrifuging, and the ejection property becomes good when the ink is used for inkjet recording. For filtration or centrifugation, any conventionally known method can be adopted, and for example, a membrane filter, a depth filter, an ultrafiltration filter and the like can be adopted for filtration. The opening of the filter is preferably 0.1 μm to 10 μm. For centrifugation, a cylindrical centrifuge, a basket-type centrifuge, or the like can be adopted.

The median diameter D50 of the aqueous colorant dispersion is preferably 5 nm to 200 nm. Further, the median diameter D50 of the water-based colorant dispersion and the average primary particle size of the colorant after salt milling shall be the median diameter D50 of the water-based colorant dispersion ≥ the average primary particle size of the colorant after salt milling. Is preferable. Within the above range, the colorant in the aqueous colorant dispersion has less aggregation and is dispersed to the level of primary particles, which is preferable because the coloring power and transparency are improved. The median diameter D50 of the aqueous colorant dispersion can be obtained from the volume-based particle size distribution measured using FPAR-1000 manufactured by Otsuka Electronics Co., Ltd.

The average circularity of the coating colorant (A) contained in the obtained aqueous colorant dispersion is preferably about 0.60 to 1.00, and the average circularity of the primary particles of the colorant after salt milling ≥ the colorant. It is preferable that the crosslinked polymer particles (A) containing the above have an average circularity. As the value of the average circularity increases, the particle shape becomes close to a true sphere, and when the aqueous colorant dispersion is used, the primary particles of the colorant tend to come into point contact with each other, and the contact area decreases, which results in viscosity. Is preferable because it decreases. The average circularity is calculated by calculating the peripheral length and area of the primary particles of 100 colorant primary particles extracted from a plurality of photographs taken at a magnification of 10,000 times with a transmission electron microscope, and using the following formula. It can be obtained by arithmetically averaging the obtained circularity. Since the average circularity represents the shape of the colorant particles when viewed from above, the three-dimensional shape of the colorant particles is not directly observed, but the colorant particles are oriented in various directions at the time of measurement. Further, as described above, in the salt milling method, the colorant particles are uniformly crushed and grown from all directions, so that the particle shape is not flat and primary particles close to a true sphere can be obtained. Therefore, 100 colorant particles. The three-dimensional shape of the colorant particles can be approximately obtained by using the arithmetic average of.
Circularity = 4π × (area) ÷ (perimeter) ^ 2

When the resin (B) has a carboxy group monomer unit, in addition to the above-mentioned production method, the phase inversion emulsification method described in JP-A-2016-069583, Japanese Patent Application Laid-Open No. 2016-069583. A dispersion treatment method that does not go through the salt milling step described in Japanese Patent Laid-Open No. 2018-0288080 [0034] to [0048], and a water-soluble inorganic salt described in Japanese Patent Application Laid-Open No. 2020-015893 [0119]. The resin (B) can be coated on the colorant by a kneading method or the like that does not use.

<Other additives>
The aqueous colorant dispersion of the present invention can contain additives. Examples of the additive include a basic compound, a surfactant, an antiseptic and antifungal agent, a chelating agent, a rust inhibitor, an antioxidant, an ultraviolet absorber, an oxygen absorber, a light stabilizer, and the like.

[Basic compound]
The basic compound is a compound capable of neutralizing the acid group when the resin (B) has an acid group. The basic compound is not particularly limited as long as it is a compound that is soluble in the aqueous medium (C). Examples of the basic compound include an inorganic base and an organic base.
Examples of the inorganic base include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide, alkali metal salts of silicic acid such as sodium orthosilicate, sodium metasilicate and sodium sesquisilicate, and trisodium phosphate. Alkali metal salts of phosphoric acid, alkali metal salts of carbonic acid such as disodium carbonate, sodium hydrogencarbonate, dipotassium carbonate, alkali metal salts of borate such as sodium borate, ammonia;
Organic bases include, for example, alkylamines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine and triethylamine, and alkanols such as aminoethanol, methylaminoethanol, dimethylaminoethanol, ethylaminoethanol, diethylaminoethanol, diethanolamine and triethanolamine. Examples thereof include amines having nonionic groups such as amines and methoxypoly (oxyethylene / oxypropylene) -2-propylamines.

The basic compound can be used alone or in combination of two or more.

[Surfactant]
Examples of the surfactant include anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants and the like.

(Anionic surfactant)
Anionic surfactants include fatty acid salts, alkyl sulfate ester salts, alkylaryl sulfonates, alkylnaphthalene sulfonates, dialkyl sulfonates, dialkyl sulfosuccinates, alkyldiaryl ether disulfonates, alkyl phosphates, polys. Oxyethylene alkyl ether sulfates, polyoxyethylene alkylaryl ether sulfates, polyoxyethylene alkyl ether acetates, alkylbenzene sulfonates (eg NH ₄ , Na, Ca, etc.), alkyl diphenyl ether disulfonates (eg NH ₄ , Na). , Ca, etc.), Naphthalene sulfonic acid formarin condensate and its salt, dialkyl succinate sulfonic acid Na salt, polyoxyethylene alkyl phosphate ester salt, glycerol volate fatty acid ester, polyoxyethylene glycerol fatty acid ester, polyoxyethylene poly Ring phenyl ether sulfate ester salts (eg NH ₄ , Na, etc.), lauryl salts, polyoxyethylene alkyl ether sulfate salts, oleates, perfluoroalkyl sulfonic acids, perfluoroalkyl sulfonates, perfluoroalkyl carboxylic acids, Perfluoroalkyl carboxylate, perfluoroalkyl phosphate ester, salt of perfluoroalkyl phosphate ester, polyoxyalkylene ether polymer with perfluoroalkyl ether group on the side chain, poly with perfluoroalkyl ether group on the side chain Examples thereof include a sulfate ester salt of an oxyalkylene ether polymer and a salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain. The counterions in the salts of these fluorine-based surfactants are, for example, Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH (CH ₂ CH ₂ OH). ) ₃ etc. can be mentioned.

(Cationic surfactant)
Examples of the cationic surfactant include an alkylamine salt, a quaternary ammonium salt, an alkylpyridinium salt, an alkylimidazolium salt and the like.

(Nonionic surfactant)
Nonionic surfactants include, for example, polyoxyethylene alkyl ether, polyoxyalkylene alkyl ether, polyoxyethylene alkyl aryl ether, polyoxyethylene oxypropylene block copolymer, polyoxyethylene polycyclic phenyl ether, sorbitan fatty acid ester, and polyoxy. Ethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene alkylamine, polyoxyethylene alkylamide, polyoxyethylene fatty acid ester, acetylene glycol, polyoxyethylene alkylamine, Examples thereof include nonionic activators such as fluorine-based and silicone-based. In particular, acetylene glycol-based surfactants include, for example, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3, Examples thereof include 5-dimethyl-1-hexin-3-ol. Examples of commercially available acetylene glycol-based surfactants include Surfinol 104, 82, 465, 485, TG, and DF110D manufactured by Air Products and Chemicals (USA).

Further, a fluorine-based surfactant can also be used. For example, Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, S-145 (all manufactured by AGC), Fulrad FC-93, FC-95. , FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M), Megafuck F-470, F1405, F-474 (all manufactured by DIC). ), ZonylTBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR (all manufactured by DuPont), FT-110, FT-250, FT-251, FT-400S, FT -150, FT-400SW (all manufactured by Neos), PF-151N (manufactured by Omniova) and the like can be mentioned.

(Ionic surfactant)
Examples of the amphoteric surfactant include alkyl betaine, alkylamine oxide, phosphadylcholine and the like. For example, laurylaminopropionate, lauryldimethylbetaine, stearyldimethylbetaine, lauryldihydroxyethylbetaine, lauryldimethylamine oxide, myristyldimethylamine oxide, stearyldimethylamine oxide, dihydroxyethyllaurylamine oxide, polyoxyethylene palm oil alkyldimethylamine. Oxides, coconut oil alkyl betaine, dimethyl lauryl betaine and the like can be mentioned.

The surfactant can be used alone or in combination of two or more.

[Preservatives and fungicides]
Examples of the antiseptic / antifungal agent include sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, sodium pentachlorophenol, methylisothiazolinone, benzisothiazolinone and the like.

[Chelating agent]
Examples of the chelating agent include sodium ethylenediamine tetraacetate, sodium nitrilo triacetate, sodium hydroxyethylethylenediamine triacetate, sodium diethylenetriamine pentaacetate, sodium uramil diacetate and the like.

[anti-rust]
Examples of the rust preventive agent include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite, benzotriazole and the like.

[Antioxidant]
Examples of the antioxidant include a phenol-based antioxidant (including a hindered phenol-based antioxidant), an amine-based antioxidant, a sulfur-based antioxidant, a phosphorus-based antioxidant, and the like.
Phenolic antioxidants include, for example, butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, stearyl-β- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate. , 2,2-Methylenebis (4-methyl-6-tert-butylphenol), 2,2-Methylenebis (4-ethyl-6-tert-butylphenol), 4,4-butylidenebis (3-methyl-6-tert-butylphenol) ), 3,9-Bis [1,1-dimethyl-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] 2,4,8,10-tetriki Saspiro [5,5] undecane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (2,4,6-tris) Examples thereof include 3,5-di-tert-butyl-4-hydroxybenzyl) benzene and tetrakis [methylene-3- (3', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate] methane.
Amine-based antioxidants include, for example, phenyl-β-naphthylamine, α-naphthylamine, N, N-di-sec-butyl-p-phenylenediamine, phenothiazine, N, N-diphenyl-p-phenylenediamine, 2,6. -Di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol, 2,4-dimethyl-6-tert-butyl-phenol, butylhydroxyanisole, 2,2-methylenebis (4-methyl-6) -Tert-butylphenol), 4,4-butylidenebis (3-methyl-6-tert-butylphenol), 4,4-thiobis (3-methyl-6-tert-butylphenol), tetrakis [methylene-3 (3,5-) Di-tert-butyl-4-dihydrokiphenyl) propionate] methane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane and the like can be mentioned.
Sulfur-based antioxidants include, for example, dilauryl 3,3-thiodipropionate, disstearylthiodipropionate, laurylstearylthiodipropionate, dimyristyl-3,3-thiodipropionate, distearyl-β, β. -Tiodipropionate, 2-mercaptobenzimidazole, dilaurylsulfide and the like can be mentioned.
Examples of the phosphorus-based antioxidant include triphenylphosphine, octadecylphosphite, triisodecylphosphite, trilauryltrithiophosphite, trinonylphenylphosphine and the like.

[UV absorber]
Examples of the ultraviolet absorber include a benzophenone-based ultraviolet absorber, a benzotriazole-based ultraviolet absorber, a salicylate-based ultraviolet absorber, a cyanoacrylate-based ultraviolet absorber, a nickel complex salt-based ultraviolet absorber, and the like.
Benzophenone-based UV absorbers include, for example, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-n-dodecyloxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2 , 2, 4,4-Tetrahydroxybenzophenone and the like.
Benzotriazole-based ultraviolet absorbers include, for example, 2- (2'-hydroxy-5'-tert-octylphenyl) benzotriazole, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2). Examples thereof include'-hydroxy-4'-octoxyphenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole and the like.
Examples of the salicylate-based ultraviolet absorber include phenylsalicylate, p-tert-butylphenylsalicylate, p-octylphenylsalicylate and the like.
Examples of the cyanoacrylate-based ultraviolet absorber include ethyl-2-cyano-3,3'-diphenylacrylate, methyl-2-cyano-3-methyl-3- (p-methoxyphenyl) acrylate, and butyl-2-cyano-. Examples thereof include 3-methyl-3- (p-methoxyphenyl) acrylate.
Nickel complex salt-based ultraviolet absorbers include, for example, nickel bis (octylphenyl) sulfate, 2,2-thiobis (4-tert-octylferate) -n-butylamine nickel (II), 2,2-thiobis (4-tert). -Octylferate) -2-ethylhexylamine nickel (II), 2,2-thiobis (4-tert-octylferate) triethanolamine nickel (II) and the like can be mentioned.

[Dye derivative]
A dye derivative can be added to the coating colorant or the aqueous colorant dispersion used in the present invention, if necessary.

The dye derivative is a compound having an acidic group, a basic group, a neutral group and the like in the organic dye residue. The dye derivative is, for example, a compound having an acidic substituent such as a sulfo group, a carboxy group or a phosphate group, an amine salt thereof, a sulfonamide group or a compound having a basic substituent such as a tertiary amino group at the terminal. Examples thereof include compounds having a neutral substituent such as a phenyl group and a phthalimidealkyl group.
Organic pigments include, for example, diketopyrrolopyrrole pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, perinone pigments, perylene pigments, thiazineindigo pigments, triazine pigments, benzimidazolone pigments, and benzoiso. Examples thereof include indol pigments such as indole, isoindolin pigments, isoindolinone pigments, quinophthalone pigments, naphthol pigments, slene pigments, metal complex pigments, azo, disazo, polyazo and other azo pigments. ..

The dye derivative can be used alone or in combination of two or more.

The aqueous colorant dispersion of the present invention can be used in various applications such as ink jet recording inks, electrostatic charge image developing toners, paints, and flexographic inks. Among these, ink jet recording ink is preferable.

<Inkjet recording ink>
The ink jet recording ink of the present invention contains an aqueous colorant dispersion. The ink for inkjet recording can contain, as an optional component, a water-soluble organic solvent that is miscible with water. As the water-soluble organic solvent, the water-soluble organic solvent already described can be used, and glycol ethers and diols are preferable. These solvents penetrate very quickly into the substrate and also penetrate into low liquid absorbent substrates such as coated paper and art paper. Therefore, it dries quickly at the time of printing, and accurate printing can be realized. Moreover, since it has a high boiling point, it has a sufficient function as a wetting agent.

As glycol ethers and diols, 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 1,2-hexanediol, 2-methyl-2,4-pentanediol and the like are preferable. , 1,2-Hexanediol is more preferred.

The water-soluble solvent can be used alone or in combination of two or more.

The content of the water-soluble solvent is preferably 3 to 60% by mass, more preferably 3 to 50% by mass in the ink for inkjet recording. The water content is preferably 10 to 90% by mass, more preferably 30 to 80% by mass in the ink jet recording ink. The content of the water-soluble solvent is the total amount with the above-mentioned aqueous medium (D).

The ink jet recording ink of the present invention may contain a binder resin. Examples of the resin type of the binder resin include acrylic resin, olefin resin, ester resin, ether resin, and urethane resin. Further, the binder resin includes a water-soluble resin, a water-insoluble resin and the like in terms of solubility in water. The water-insoluble resin contains an emulsion.

The content of the binder resin is preferably 2 to 30% by mass, more preferably 3 to 20% by mass, based on 100% by mass of the non-volatile content of the inkjet recording ink.

The ink jet recording ink of the present invention may contain known additives as other additives.

The ink for inkjet recording is preferably filtered. This improves the ejection property from the inkjet printer. For filtration, any conventionally known method can be adopted.

The inkjet recording ink of the present specification can be suitably used for various inkjet printers. The applicable inkjet method is not particularly limited, and examples thereof include a charge control type, a continuous injection type such as a spray type, a piezo method, a thermal method, and an electrostatic suction method.

The ink set of the present invention is C.I. I. Pigment Red 31, and C.I. I. Inkjet recording ink (magenta) formed from coating colorant (A) containing pigments other than Pigment Red 31, and other colors (cyan, yellow, black, white, red, green, blue). , Orange, pink, gold, silver, bronze, etc.) Includes inkjet recording inks.

The inkjet recording ink of the present specification can be mounted as a set with cyan ink, yellow ink, and black ink when mounted on various inkjet printers. By using a four-color ink set called a so-called process color and adjusting the coating amount of each color, images of various hues can be formed on the object to be coated. Further, by mounting inks other than process colors such as red ink, orange ink, and green ink as needed, an image with higher color reproducibility can be formed. The pigment concentration, viscosity, dynamic viscoelasticity, surface tension, coating order, evaporation rate of volatile components, etc. of each ink are design items, and can be appropriately adjusted according to the desired characteristics.

[Base material]
The ink of the present invention can be applied to various conventionally known substrates. The base material includes high water absorption base material such as plain paper, cloth and knit, low water absorption base material such as art paper, coated paper, vinyl chloride, wood, concrete, polyethylene film, polypropylene film and polyethylene terephthalate film, and metal. Examples include non-water-absorbent substrates such as (aluminum, stainless steel, etc.).

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the Examples. Unless otherwise specified, "part" is a mass part and "%" is a mass%. Further, NV means a non-volatile content.

The abbreviations and product names in the examples mean the following.
BzMA: Benzyl methacrylate BzA: Benzyl acrylate St: Styrene AS-6: Styrene macromer manufactured by Toagosei Co., Ltd. (number average molecular weight 6,000)
CHMA: Cyclohexyl Methacrylic Acid BHA: Behenyl Acrylate PEMA: Phenoxyethyl Methacrylate STMA: Stearyl Methacrylate LA: Lauryl Acrylate AM-90G: Shin-Nakamura Chemical Co., Ltd. methoxypolyethylene glycol # 400 acrylate AMP-20GY: Shin-Nakamura Chemical Co., Ltd. : Methacrylic acid AA: Acrylic acid MMA: Methyl methacrylate VI: Vinyl imidazole AcAm: acrylamide Unilube PKA-5013: Polyethylene glycol-polyethylene glycol-allyl ether manufactured by Nichiyu Co., Ltd. (number average molecular weight 2,000)
Light acrylate 130A: Kyoeisha Chemical Co., Ltd. methoxypolyethylene glycol acrylate MeOH: Methanol IPA: Isopropyl alcohol NaOH: Sodium hydroxide KOH: Potassium hydroxide NH ₃ : Ammonia
DMAE: Dimethylaminoethanol Crosslinking Agent 1: Denacol EX-321 (aliphatic epoxy) manufactured by Nagase ChemteX.
Crosslinking agent 2: Denacol EX-411 manufactured by Nagase ChemteX Co., Ltd.
Crosslinking agent 3: Denacol EX-252 manufactured by Nagase Chemtex Co., Ltd.
BDG: Diethylene glycol Monobutyl ether PG: Propylene glycol GR: Glycerin MEK: Methyl ethyl ketone Takelac W-6110: Polyurethane emulsion manufactured by Mitsui Chemicals, Inc. (NV32%)
Takelac W-6061: Polyurethane emulsion manufactured by Mitsui Chemicals (NV30%)
Takelac W-5030: Polyurethane emulsion manufactured by Mitsui Chemicals (NV30%)
Byronal MD-2000: Toyobo Polyester Emulsion (NV40%)
Joncryl 780: Polyacrylic emulsion manufactured by BASF Japan (NV48%)
Joncryl HPD96: Acrylic resin manufactured by BASF Japan (NV34%)
Chemipearl W400S: Olefin wax manufactured by Mitsui Chemicals (NV40%)
Surfinol DF110D: Evonik Industries acetylene surfactant Surfinol 465: Evonik Industries acetylene surfactant BYK-348: Big Chemie silicon surfactant Proxel GXL: London preservative Neocintoll BC- 493: Preservative PR31 manufactured by Sumika Environmental Science Co., Ltd .... C.I. I. Pigment Red 31
PR100 ... C.I. I. Pigment Red 100
PR122 ... C.I. I. Pigment Red 122
PR146 ... C.I. I. Pigment Red 146
PR147 ... C.I. I. Pigment Red 147
PR150 ... C.I. I. Pigment Red 150
PR185 ... C.I. I. Pigment Red 185
PR202 ... C.I. I. Pigment Red 202
PR269 ... C.I. I. Pigment Red 269
PV19 ... C.I. I. Pigment Violet 19
PR176 ... C.I. I. Pigment Red 176
PR177 ... C.I. I. Pigment Red 177
PR242 ... C.I. I. Pigment Red 242
PR254 ... C.I. I. Pigment Red 254

The physical property values were obtained according to the following method.

(Number average molecular weight (Mn))
It was measured by gel permeation chromatography (GPC) equipped with an RI detector. Using HLC-8220GPC (manufactured by Tosoh Co., Ltd.) as an apparatus, two separation columns are connected in series, and "TSK-GEL SUPER HZM-N" is connected in two for both fillers, and the oven temperature is 40 ° C. , A THF solution was used as an eluent, and the measurement was performed at a flow rate of 0.35 ml / min. The sample was dissolved in a solvent consisting of 1% of the above eluent and injected in 20 microliters. The molecular weight is a polystyrene-equivalent value.

(Acid value)
The number of moles of acid groups contained in 1 g of the resin was calculated from the monomer composition. The theoretical value of the acid value (mgKOH / g) was calculated assuming that the number of moles of this acid group is equal to the number of moles of potassium hydroxide (molecular weight 56.1) required for neutralization.

(Non-volatile content)
The non-volatile content was determined from the dry weight loss when 0.5 g of the object to be measured was precisely weighed and placed in a 180 ° C. dryer for 20 minutes.

(Crosslink value)
The cross-linking value was calculated from the following formula.
Crosslink value = number of moles of epoxy group in crosslinker (D) / number of moles of acid group in resin (B)

(Neutralization value)
The neutralization value was calculated from the following formula.
Neutralization value = number of moles of basic compound / number of moles of acid group of resin (B)

<Synthesis of resin (B)>
[AB block polymer]
-Synthesis of resin (B-1) (synthesis of A polymer block)
Diethylene glycol dimethyl ether (hereinafter referred to as diglyme) 295.68 parts, iodine 3.03 parts, azobis (methoxydimethylvaleronitrile) in a 1-liter separable flask reactor equipped with a stirrer, backflow condenser, thermometer and nitrogen introduction tube. (Fujifilm Wako Pure Chemical Industries, Ltd., trade name: V-70) 7 parts, dit-butylhydroxytoluene (hereinafter referred to as BHT) 0.66 parts, BzMA 18 parts (10 mol%), PEMA 62 parts 24 parts (10 mol%) of AMP-20GY was added (30 mol%), the mixture was heated to 40 ° C. with flowing nitrogen, polymerized for 6.5 hours, and then 2 parts of V-70 was added. Then, 1 hour later, 2 hours later, and 3 hours later, 2 parts of V-70 were added respectively, and the reaction was further continued for 2 hours. After confirming that the polymerization conversion rate was 95% or more by sampling, the reaction was terminated to prepare an A polymer block. The polymerization conversion rate converted from the non-volatile content was 95%, and the number average molecular weight (Mn) was 4,000.

(Synthesis of block polymer)
To the above reaction solution, add a mixture of 39 parts (45 mol%) of MAA, 5 parts (3 mol%) of BzA, 2 parts (2 mol%) of MMA, and 0.45 parts of V-70, and polymerize for 4.5 hours. The B block was synthesized. The polymerization rate obtained by sampling and converting from the non-volatile content was 97.6%. This B polymer block did not polymerize with the constituent monomers of the A polymer block.
Next, 147.8 parts of BDG was added, 1 part of sodium hydroxide and 129.3 parts of ion-exchanged water were added, and the mixture was reacted at 50 ° C. for 2 hours to decompose iodine at the polymer terminal and resin. (B-1) (number average molecular weight (Mn): 6,000, acid value 169 mgKOH / g) was prepared.

-Synthesis of Resins (B-2) and (B-3) The resin (B-2) was the same as the resin (B-1) except that the monomer composition and the number average molecular weight were changed as shown in Table 1. ), (B-3) were prepared. The molecular weight was adjusted by changing the amount of V-70 added.

[Random polymer]
-Synthesis of resin (B-4) A reaction vessel equipped with a stirrer, a backflow condenser, a dropping funnel, a thermometer and a nitrogen introduction tube was prepared. 35 parts (30 mol%) of MAA, 18 parts (13 mol%) of AA, 11 parts (11 mol%) of MMA, 3 parts (5 mol%) of BzMA, 6 parts (6 mol%) of St, 5 parts of AS-6. 2 parts (5 mol%), 2 parts (5 mol%) of AMP-20GY, 2 parts (5 mol%) of PEMA, 1 part (5 mol%) of STMA, 2 parts (5 mol%) of LA, 1 part (5 mol%) of BHA. %) And 5 parts (5 mol%) of VI were mixed to prepare a monomer mixed solution. In the reaction vessel, 20 parts of MEK, 0.3 part of 2-mercaptoethanol (chain transfer agent), and 10% of the above-mentioned monomer mixed solution were put and mixed, and nitrogen gas replacement was sufficiently performed.
On the other hand, in the dropping funnel, the remaining 90% of the monomer mixture, 0.27 part of the chain transfer agent, 60 parts of MEK, and 2,2'-azobis (2,4-dimethylvaleronitrile) (Fujifilm Wako Pure Chemical Industries, Ltd.) Yakusha Co., Ltd., trade name: V-65) Put 2.2 parts of the mixed solution, raise the temperature to 65 ° C. while stirring the monomer mixed solution in the reaction vessel under a nitrogen atmosphere, and put it in the dropping funnel. The mixed solution was added dropwise over 3 hours. After 2 hours had elapsed at 65 ° C. from the end of the dropping, a solution in which 0.3 part of the polymerization initiator was dissolved in 5 parts of MEK was added, and the mixture was further aged at 65 ° C. for 2 hours and at 70 ° C. for 2 hours. The solvent of the obtained product was concentrated under reduced pressure and completely removed to prepare a resin (B-4) (number average molecular weight (Mn): 11,700, acid value 171 mgKOH / g).

-Synthesis of resins (B-5) to (B-7) Resins (B-5) to (B-7) are the same as the resin (B-4) except that the monomer composition is changed as shown in Table 2. -7) was prepared. The molecular weight was adjusted as appropriate by changing the amount of V-65 added.

-In a reaction vessel equipped with a synthetic gas introduction tube for resin (B-8), a thermometer, a condenser, a dropping funnel, and a stirrer, 51 parts (50 mol%) of maleic anhydride as a monomer mixture, as α-olefin. 15 parts (50 mol%) of 1-tetracosene, 100 parts of MEK, and 0.5 part of octyl thioglycolate as a chain transfer agent were charged, substituted with nitrogen, and then heated to 105 ° C. with stirring. A mixture of 2.0 parts of dimethyl asobisisobutyrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name: V-601) and 5 parts of MEK was added dropwise thereto as a radical polymerization initiator over 1 hour. Then, while stirring at a temperature of 85 ° C., a mixture of 5 parts of V-601 and 12 parts of MEK was added dropwise over 6 hours, and the mixture was reacted for 1 hour while maintaining the temperature at 85 ° C. to produce maleic anhydride as an acid anhydride group. A polymer having the above was obtained. Subsequently, 83 parts (50 mol%) of IPA (isopropyl alcohol) and 0.1 part of diazabicycloundecene as a catalyst were added, and the mixture was stirred and reacted for 6 hours while keeping the temperature at 85 ° C. to react with maleic anhydride. Was opened and half-esterified. The solvent of the obtained product was concentrated under reduced pressure and completely removed to prepare a resin (B-8) (number average molecular weight (Mn): 8,200, acid value 113 mgKOH / g).

-Resin (B-9) to (B-) in the same manner as the resin (B-8) except that the synthetic raw materials and compositions of the resins (B-9) to (B-19) were changed as shown in Table 3. 19) was produced. The molecular weight was adjusted as appropriate by changing the amount of dimethyl asobisisobutyrate added.

<Manufacturing of coating colorants>
[Manufacturing Example 1]
-Production of Coating Colorant (1) To 540 parts of water cooled to 5 ° C., 30 parts of the compound represented by the following general formula (1) and 51 parts of a 35 mass% hydrochloric acid aqueous solution were added, and the mixture was stirred for 1 hour. Subsequently, a solution prepared by dissolving 9 parts of sodium nitrite in 30 parts of water was added, and the mixture was stirred for 1 hour to carry out a diazotization reaction. An appropriate amount of sulfamic acid was added to this solution to eliminate excess sodium nitrite. Further, an aqueous solution obtained by mixing 50 parts of a 25 mass% sodium hydroxide aqueous solution and 65 parts of an 80 mass% acetic acid aqueous solution was added and stirred to obtain a diazotized solution.
To another container, add 660 parts of water, 9 parts of the compound represented by the following general formula (2), 21 parts of the compound represented by the following general formula (3), and 34 parts of a 25 mass% sodium hydroxide aqueous solution. Then, a coupler solution containing the compounds represented by the general formulas (2) and (3) was obtained.
The coupler solution was added dropwise to the diazotized solution over 1 hour while maintaining 5 ° C, then stirred at 5 ° C for 2 hours, heated to 30 ° C and stirred for 2 hours, then heated to 80 ° C and 1 The colorant particles (1) containing PR150 and PR31 in a mass ratio of 75:25 were obtained by stirring for a time, repeating filtration and washing with water, drying and pulverizing.
30 parts of the obtained colorant particles (1), 12 parts of the resin (B-1) as a non-volatile component, 58 parts of ion-exchanged water, and 100% of the acid group of the resin (B-1) of sodium hydroxide. The amount to be added was added and mixed, and circulation and dispersion were performed for 1 hour using a high-pressure homogenizer (Starburst Mini manufactured by Sugino Machine Limited, processing pressure 200 MPa). While stirring the obtained solution, add a 35% aqueous hydrochloric acid solution in an amount 1.2 mol times the number of moles of the added sodium hydroxide, and add the resin (B-1) to the colorant particles (1). A wet cake containing the coating colorant (1) in which the colorant particles (1) were coated with the resin (B-1) was prepared by repeatedly precipitating and coating the surface of the above-mentioned material, filtering and washing with water. The non-volatile content was 30% by mass.

[Manufacturing Example 2]
-Manufacturing of coating colorant (2) C. I. 27 copies of Pigment Red 150, C.I. I. 9 parts of Pigment Red 31, 12 parts of resin (B-2) as non-volatile content, 175.0 parts of sodium chloride as water-soluble inorganic salt (X), and 30.0 parts of diethylene glycol as water-soluble organic solvent (Y) are stainless steel. It was charged in a 1-gallon kneader (manufactured by Inoue Seisakusho) and kneaded at 90 ° C. for 3 hours.
The obtained kneaded product was put into 2,000 parts of ion-exchanged water, stirred, filtered, and washed with water, and this process was repeated to remove sodium chloride and diethylene glycol, whereby the colorant particles were made into a resin (B-2). A wet cake containing the coating colorant (2) coated with) was prepared. The non-volatile content was 30% by mass.

[Manufacturing Examples 3 to 50]
-Production of coating colorants (3) to (50) The coating colorants (3) are the same as in Production Example 2 except that the types and ratios of the colorants and the resin (B) are changed as shown in Table 4. ~ (50) was prepared.

<Manufacturing of water-based colorant dispersion>
[Example 1]
-Production of water-based colorant dispersion (1) Neutralize 30 parts of the coating colorant (1) in terms of non-volatile content, 40 parts of ion-exchanged water as the water-based medium (C), and potassium hydroxide as the basic compound. Add to a value of 0.8, stir using a disper to make the inside of the system uniform, and use a high-pressure homogenizer (Sugino Machine Limited Starburst Mini, processing pressure 180 MPa) to circulate and disperse for 3 hours. rice field. The liquid temperature during dispersion was adjusted to 40 to 80 ° C.
After dispersion, adjust the liquid temperature to 40 ° C., add an appropriate amount of the cross-linking agent 1 as the cross-linking agent (D) so that the cross-linking value becomes 0.9, and use a disper at 70 ° C. and 1 After stirring for hours, a cross-linking reaction was carried out.
After stirring, adjust the liquid temperature to 60 ° C, add 0.03 parts of Neosintol BC-493 as a preservative, and add an appropriate amount of ion-exchanged water so that the non-volatile content becomes 25%, and use a circulating centrifuge. After centrifuging for 1 hour, filtration was performed to prepare an aqueous colorant dispersion (1).

[Example 2]
-Production of water-based colorant dispersion (2) Neutralize 30 parts of the coating colorant (2) in terms of non-volatile content, 40 parts of ion-exchanged water as the water-based medium (C), and potassium hydroxide as the basic compound. Add to a value of 0.8, stir to make the inside of the system uniform using a disper, and perform pass dispersion 8 times using a high-pressure homogenizer (Sugino Machine Limited Starburst Mini, processing pressure 220 MPa). rice field. The liquid temperature during dispersion was adjusted to 40 to 80 ° C.
After dispersion, adjust the liquid temperature to 40 ° C., add an appropriate amount of the cross-linking agent 1 as the cross-linking agent (D) so that the cross-linking value becomes 0.9, and use a disper at 70 ° C. and 1 After stirring for hours, a cross-linking reaction was carried out.
After stirring, adjust the liquid temperature to 50 ° C, add 0.03 part of Neosintol BC-493 as a preservative, centrifuge for 3 passes using a cylindrical centrifuge, and further reduce the non-volatile content to 25%. An appropriate amount of ion-exchanged water was added so as to be, and filtration was performed to prepare an aqueous colorant dispersion (2).

[Examples 3 to 49, 53 to 71, Comparative Examples 3 and 4]
-Production of water-based colorant dispersions (3) to (49) and (53) to (73) Other than changing the coating colorant, cross-linking agent, basic compound, cross-linking value, and neutralization value as shown in Table 5. Made aqueous colorant dispersions (3) to (49) and (53) to (73) in the same manner as in Example 2. No cross-linking agent was added to the examples having a cross-linking value of 0.

[Example 45]
-Production of water-based colorant dispersion (50) As the water-based medium (C), a mixed solvent of 35 parts of ion-exchanged water and 5 parts of BDG was used, and a coating colorant, a cross-linking agent, a basic compound, a cross-linking value, and neutralization were used. An aqueous colorant dispersion (50) was prepared in the same manner as in Example 2 except that the values were changed as shown in Table 5.

[Example 47]
-Production of water-based colorant dispersion (51) As the water-based medium (C), a mixed solvent of 32 parts of ion-exchanged water and 8 parts of PG was used, and a coating colorant, a cross-linking agent, a basic compound, a cross-linking value, and neutralization were used. An aqueous colorant dispersion (51) was prepared in the same manner as in Example 2 except that the values were changed as shown in Table 5.

[Example 48]
-Production of water-based colorant dispersion (52) As the water-based medium (C), a mixed solvent of 30 parts of ion-exchanged water and 10 parts of GR was used, and a coating colorant, a cross-linking agent, a basic compound, a cross-linking value, and neutralization were used. An aqueous colorant dispersion (52) was prepared in the same manner as in Example 2 except that the values were changed as shown in Table 5.

<Evaluation of viscosity stability under temperature fluctuation storage>
The viscosity of the prepared aqueous colorant dispersion was measured using a cone plate type viscometer TV-22 manufactured by Toki Sangyo Co., Ltd., and the initial viscosity was V _b . This aqueous colorant dispersion was placed in a 20 mL glass sample tube and stored at 5 ° C for 6 hours, 25 ° C for 6 hours, 50 ° C for 6 hours, and 25 ° C for 6 hours for 90 days. After that, the aqueous colorant dispersion was taken out from the closed container, cooled to room temperature, measured in the same manner as the initial viscosity, and used as the viscosity with time _Va . The value of V _a / V _b obtained by dividing the value of viscosity with time by the value of initial viscosity was calculated, and the viscosity stability was evaluated according to the following criteria.
⊚: V _a / V _b value is less than 105% (excellent)
◯: The value of V _a / V _b is 105% or more and less than 110% (good).
Δ: The value of V _a / V _b is 110% or more and less than 115% (no problem in practical use).
X: The value of V _a / V _b is 115% or more (defective)

<Evaluation of filterability under temperature fluctuation storage>
50 parts of the aqueous colorant dispersion subjected to the temperature fluctuation cycle test for 90 days was weighed and filled in a syringe. A 25 mm syringe filter 1.0 GMF (corresponding to an opening of 1 μm) manufactured by hatman was attached to the tip of the syringe, and the syringe was manually pushed to filter the aqueous colorant dispersion, and the filterability was evaluated according to the following criteria.
◎: The whole amount passes through the syringe filter (excellent)
◯: 40 g or more and less than 50 g passed through the syringe filter (good)
Δ: 20 g or more and less than 40 g passes through the syringe filter (no problem in practical use)
×: Less than 20 g passes through the syringe filter (practically impossible)

The composition, parameters and evaluation results are summarized in Table 5. In the table, water means ion-exchanged water.

From the results of Tables 5-1 to 5-3, the aqueous colorant dispersion of the present invention has good viscosity stability and good filterability even in a harsh environment where the storage temperature fluctuates. In particular, the water-based colorant dispersion using the resin (B) having an α-olefin unit as the hydrophobic group has particularly good evaluation results.

<Manufacturing ink for inkjet recording>
[Example 72]
-Manufacture of ink for inkjet recording (1) 33 parts of water-based colorant dispersion (1), 5 parts of BDG, 15 parts of 1,2-propanediol, 8.8 parts of Joncryl HPD96, and 1. of Chemipearl W400S. 25 parts, 0.5 part of Surfinol DF110D, 1 part of BYK-348, 0.1 part of triethanolamine, 0.15 part of Proxel GXL, 35.2 parts of ion-exchanged water are mixed, 0.5 μm. Inkjet recording ink (1) was prepared by filtering with a membrane filter.

[Examples 73 to 140, Comparative Examples 5 and 6]
Production of Inkjet Recording Inks (2) to (71), (77), (78) Inkjet recording in the same manner as in Example 72 except that the aqueous colorant dispersion used was changed as shown in Table 6. The inks (2) to (71), (77), and (78) for use were prepared.

[Example 141]
-Manufacture of ink for inkjet recording (72) 33 parts of water-based colorant dispersion (10), 5 parts of 1,2-hexanediol, 15 parts of 1,2-butanediol, 9.4 parts of Takelac W-6110 1.25 parts of Chemipearl W400S, 0.5 parts of Surfinol DF110D, 1 part of BYK-348, 0.1 parts of triethanolamine, 0.15 parts of Neosintol BC-493, ion-exchanged water 34. Six parts were mixed and filtered with a 0.5 μm membrane filter to prepare an ink jet recording ink (72).

[Example 142]
-Manufacture of ink for inkjet recording (73) 33 parts of water-based colorant dispersion (10), 5 parts of BDG, 15 parts of 1,2-butanediol, 6.25 parts of Joncry780, 0 parts of Surfinol DF110D. Mix 5 parts, 1 part BYK-348, 0.1 part triethanolamine, 0.15 part Proxel GXL, and 39 parts ion-exchanged water, filter with a 0.5 μm membrane filter, and ink jet recording ink ( 73) was produced.

[Example 143]
-Manufacture of ink for inkjet recording (74) 33 parts of water-based colorant dispersion (10), 5 parts of diethylene glycol monoisobutyl ether, 15 parts of 1,2-butanediol, 10 parts of Takelac W-5030, surfinol Mix 0.5 part of 465, 1 part of BYK-348, 0.1 part of triethanolamine, 0.15 part of Proxel GXL, and 35.25 parts of ion-exchanged water, and filter with a 0.5 μm membrane filter. , Inkjet recording ink (74) was produced.

[Example 144]
-Manufacture of ink for inkjet recording (75) 33 parts of water-based colorant dispersion (10), 5 parts of diethylene glycol monoisobutyl ether, 15 parts of 1,2-propanediol, 10 parts of Takelac W-6061, surfinol Mix 0.5 part of 465, 1 part of BYK-348, 0.1 part of triethanolamine, 0.15 part of neosynthol BC-493 and 35.25 parts of ion-exchanged water, and use a 0.5 μm membrane filter. Filtration was performed to prepare an ink jet recording ink (75).

[Example 145]
-Manufacture of ink for inkjet recording (76) 33 parts of water-based colorant dispersion (10), 5 parts of 1,2-hexanediol, 15 parts of 1,2-propanediol, 7.5 of Vironal MD-2000. 1.25 parts of Chemipearl W400S, 0.5 parts of Surfinol DF110D, 1 part of BYK-348, 0.1 parts of triethanolamine, 0.15 parts of Neosintol BC-493, ion-exchanged water 37. 75 parts were mixed and filtered with a 0.5 μm membrane filter to prepare an ink jet recording ink (76).

<Evaluation of discharge stability under temperature fluctuation storage>
The tank filled with the created inkjet recording ink was mounted as magenta ink on PX-105 (piezo type inkjet printer) manufactured by Seiko Epson, and 100 sheets of solid image inkjet recording were recorded on A4 size plain paper as a base material. I went continuously. The state of the nozzle of the inkjet head of the printer and the obtained 100th solid image was visually observed and evaluated according to the following criteria.
⊚: Nozzle was not clogged and no blur was observed in the solid image (excellent).
◯: Nozzle was not clogged, but one or two blurs were observed in the solid image (good).
Δ: Nozzle was not clogged, but 3 to 9 blurs were observed in the solid image (no problem in practical use).
X: Nozzle clogging occurred, or 10 or more blurs were observed in the solid image (practically impossible).

<Evaluation of color reproducibility>
The prepared tank filled with ink for inkjet recording was mounted as magenta ink on PX-105 (piezo type inkjet printer) manufactured by Seiko Epson Corporation. In addition, an inkjet printing printer capable of four-color printing equipped with ICC69 (cyan ink), ICY69 (yellow ink), and ICBK69 (black ink) manufactured by Seiko Epson was prepared. A total of 6 solid images of magenta single color, cyan single color, yellow single color, magenta + cyan secondary color, cyan + yellow secondary color, and yellow + magenta secondary color are printed on A4 size plain paper as a base material, and hot air is used. After drying, L * a * b * of a solid image was measured. The measured 6 points a * and b * were plotted on the plane coordinates, and a hexagonal figure was drawn. The area of this hexagonal figure was calculated, and the color reproducibility was evaluated based on the following criteria with the area of the hexagonal figure drawn using the ink (68) of Comparative Example 5 as a reference (100%).
⊚: Area over 103% (significant difference, excellent)
◯: Area 101% or more and 103% or less (significant difference, good)
Δ: Area 100% or more and 101% or less (significant difference, no problem in practical use)
×: Area 100% or less (no significant difference, practically impossible)

The evaluation results are shown in Table 6.

From the results shown in Tables 6-1 to 6-3, the ink jet recording ink using the aqueous colorant dispersion of the present invention has good ejection stability even in a harsh environment where the temperature fluctuates, and color reproduction is achieved. The area is wide. In particular, a resin (B) having an α-olefin unit as a hydrophobic group is used, and C.I. I. Pigment Red 31 and C.I. I. Inkjet recording inks in which the ratio of pigments other than Pigment Red 31 is in a preferable range have particularly good evaluation results.
Further, when the base material was changed to coated paper, polypropylene film (OPP film), polyethylene terephthalate film, and aluminum foil, and color reproducibility was evaluated, the same results were obtained. When the base material was not paper, the base material was attached to A4 plain paper and used.
In addition, a tank filled with a water-based colorant dispersion prepared using a Canon MAXIFY MB5430 (thermal inkjet printer) is mounted as magenta ink, and Canon PGI-2300C (cyan ink) and PGI-2300Y (yellow) are mounted. Inkjet printing printers equipped with ink) and PGI-2300BK (black ink) capable of printing in four colors were prepared, and color reproducibility was evaluated. Similar results were obtained.

Claims (10)

Containing a coating colorant (A) and an aqueous medium (C)
The coating colorant (A) contains the colorant particles and the resin (B) that coats the colorant particles.
The colorant particles are C.I. I. Pigment Red 31, and C.I. I. Contains pigments other than Pigment Red 31
The resin (B) is selected from the group consisting of a (meth) acrylic acid ester monomer unit having an alkyl group, an aromatic monomer unit, a heterocyclic monomer unit, and an α-olefin monomer unit. An aqueous colorant dispersion, which is a polymer containing one or more hydrophobic monomer units. The C.I. I. The aqueous colorant dispersion according to claim 1, wherein the pigment other than Pigment Red 31 is a pigment having no nitro group. The C.I. I. 1. A pigment having a structure selected from the group consisting of a naphthol structure, a quinacridone structure, a diketopyrrolopyrrole structure, and an azo structure (provided that the pigment does not have a naphthol structure) is a pigment other than Pigment Red 31. Alternatively, the aqueous colorant dispersion according to 2. The aqueous colorant dispersion according to any one of claims 1 to 3, wherein the resin (B) is a polymer containing a carboxy group-containing monomer unit. The aqueous colorant dispersion according to claim 4, wherein the acid value of the resin (B) is 1 to 350 mgKOH / g. The aqueous colorant dispersion according to any one of claims 1 to 5, further comprising a cross-linking agent (D). C. I. Pigment Red 31, and C.I. I. The aqueous colorant dispersion according to any one of claims 1 to 6, wherein the content ratio of the pigment other than Pigment Red 31 is 5:95 to 50:50 in mass ratio. An ink containing the aqueous colorant dispersion according to any one of claims 1 to 7. An ink set comprising the ink according to claim 8. An image forming object comprising an image formed from a substrate and the ink according to claim 8 or the ink set according to claim 9.