JP2002332441A - Ink, method for producing the same and method of ink-jet image formation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide ink suitable in thermal, piezoelectric, electric field or acoustic ink-jet system, having excellent handleability, odorlessness and safety, excellent in the dispersion stability and durability of a dispersed phase, slight in cloggings on a nozzle tip, good in color developability and color tone (hue) when printed on a sheet of arbitrarily chosen paper, high in ink penetration for photographic paper, excellent in water resistance, light resistance, especially fretting resistance after printed, and capable of printing in high density and high image quality. SOLUTION: This ink essentially comprises water, a water-miscible organic solvent and colorant-containing microparticles; wherein the colorant-containing microparticles are obtained by coprecipitation of a water-insoluble colorant and a polymeric dispersant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink, a method for producing the ink, and a method for forming an ink jet image using the ink.

[0002]

2. Description of the Related Art In recent years, with the spread of computers, ink jet printers have been widely used not only in offices but also at home for printing on paper, film, cloth and the like. As inks for inkjet recording, oil-based inks, aqueous inks, and solid inks are known.Among these, aqueous inks are advantageous in terms of ease of production, handleability, odor, safety, and the like. Water-based inks have become mainstream.

However, aqueous inks using water-soluble dyes have the advantages of high transparency and high color density,
When printed on so-called plain paper, the water resistance is poor, and there is a problem in that bleeding occurs and the print quality is reduced, and the light resistance is poor. Therefore, attempts have been made to use water-insoluble colorants such as pigments and disperse dyes for the purpose of solving the above problems,
When the particle size of the colorant is reduced to improve transparency and print quality, light resistance deteriorates, and the use of porous inorganic materials on the surface has been used due to the recent increase in image quality of inkjet technology. When a recording paper provided with an image receiving layer containing fine particles (hereinafter sometimes referred to as "photographic quality paper") is used, there is a problem that the abrasion resistance is not sufficient. In the case of conventionally well-known dyes and pigments to which a color index (C.I.) number is assigned, an appropriate absorption wavelength and half wavelength effective for improving color reproducibility on an image receiving material are used. It is poor in colorants having a range of values, particularly has a good magenta color tone or cyan color tone, and it is difficult to achieve both color tone and fastness.

JP-A-9-59552 and 9-1111
No. 63, No. 9-258587, No. 10-36728
JP-A-11-286637 and JP-A-11-286637 disclose that the above-mentioned color tone can be improved by using a dye obtained by coupling an aromatic diamine to a color photographic coupler. However, in these, the particle size or particle size distribution of the dispersion tends to be large, and the dispersion stability and printability are not sufficient, and the abrasion resistance is not sufficient, and discoloration to an oxidizing gas such as ozone is caused. There is a problem of scarcity. On the other hand, for the purpose of improving the color tone, Japanese Patent Application No. 11-366571 describes an ink jet recording ink containing a dye capable of forming a J-aggregate. However, according to the study of the present inventors, when ink-jet recording is performed with an ink containing a J-aggregate of such a dye, although a vivid color tone is obtained, depending on an image receiving paper, short-waves which are considered to be due to aggregation of particles are considered. Ingredients appear,
It has been found that a metallic gloss, that is, a phenomenon called bronze, due to specular reflection light on the surface of the pigment particles may be strongly observed.

[0005] As described above, there is no clogging at the nozzle tip, excellent in ejection stability, excellent in color development and color tone (hue) without dependence on paper, and water resistance after printing even when the photographic quality paper is used. At present, there is no ink jet recording ink which is excellent in light resistance, scratch resistance, and enables high-density, high-quality recording.

[0006]

SUMMARY OF THE INVENTION The present invention provides a thermal,
Suitable for piezoelectric, electric field or acoustic ink jet system, it has handleability, odor and safety, excellent dispersion stability and storage stability of dispersion, less occurrence of clogging at the nozzle tip, and paper dependence Excellent in color development when printing on paper selected arbitrarily, especially excellent in color tone (hue), excellent in ink penetration into photographic quality paper, excellent in water resistance and light resistance after recording, especially excellent in abrasion resistance It is an object of the present invention to provide an ink capable of recording with high density and high image quality. In addition, the present invention has handleability, odor, and safety, eliminates ejection failure due to clogging at the nozzle tip, and has no color dependency when printing on arbitrarily selected paper, particularly color tone ( Hue), excellent ink permeability to photographic quality paper, excellent water resistance and light resistance after recording, especially excellent scratch resistance, and an ink jet recording method capable of recording with high density and high image quality. With the goal.

[0007]

Means for solving the above problems are as follows. That is, <1> an ink containing at least water, a water-soluble organic solvent, and colorant-containing fine particles, wherein the colorant-containing fine particles are produced by co-precipitating a water-insoluble colorant and a polymer dispersant. An ink characterized by the following. <2> The colorant-containing fine particles are prepared by adding water to an organic solvent phase containing a water-insoluble colorant and a polymer dispersant, and by adding the organic solvent phase to water. The ink according to <1>, which is manufactured. <3> The ink according to <1> or <2>, wherein the water-insoluble colorant is a dye that forms a J-aggregate. <4> A method for producing an ink containing at least water, a water-soluble organic solvent and colorant-containing fine particles, wherein the colorant-containing fine particles are co-precipitated with a water-insoluble colorant and a polymer dispersant, and then dispersed. A method for producing an ink, characterized by being produced using a medium. <5> An image is formed by using an image receiving paper having an image receiving layer containing white inorganic pigment particles on a support, and using the ink according to any one of <1> to <3>. Ink jet image forming method.

[0008] In the present invention, the following means are preferably mentioned. <6> The content according to any one of <1> to <3>, wherein the content of the ionic group contained in the polymer dispersant is 0.2 to 4.0 mmol / g. ink. <7> The ionic group contained in the polymer dispersant is a carboxylic acid or a sulfonic acid.
The ink according to any one of <3> and <6>. <8> The polymer dispersant has a glass transition temperature of −50 ° C. or more and 150 ° C. or less, <1> to <3.
>, <6> or <7>. <9> The colorant-containing fine particles have an average particle size of 10 nm to 3
The ink according to any one of <1> to <3> or <6> to <8>, having a thickness of 00 nm.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the ink of the present invention, a method for producing the ink, and a method for forming an ink jet image will be described.

The ink of the present invention contains colorant-containing fine particles, water, and a water-soluble organic solvent. The colorant-containing fine particles are produced by coprecipitating a water-insoluble colorant and a polymer dispersant. Hereinafter, the constituent components will be specifically described.

-Water-insoluble colorant- As used herein, the term "water-insoluble colorant" means a colorant that is almost insoluble or hardly soluble in water, and examples thereof include oil-soluble dyes and disperse dyes. And the like, a dye forming a J-aggregate, a disperse dye, a pigment, a dye forming a J-aggregate is preferable, and a disperse dye and a dye forming a J-aggregate are more preferable. Are particularly preferred.

The oil-soluble dye is not limited to the following, but particularly preferred specific examples are CI Solvent Black Series; CI Solvent Yellow Series;
CI Solvent Red Series; CI Solvent
Bio Red Series; CI Solvent Blue Series; CI Solvent Green Series; and CI Solvent Orange Series.

The disperse dye is not limited to the following, but particularly preferred specific examples are CI Disperse Yellow Series; CI Disperse Orange Series;
CI Dispers Bio Series; CI Dispers Blue Series; and CI Dispers Green Series.

The type of the pigment is not particularly limited, and all conventionally known organic and inorganic pigments can be used. For example, azo lake, azo pigment, phthalocyanine pigment, perylene and perinone pigment, anthraquinone pigment,
Polycyclic pigments such as quinacridone pigments, dioxazine pigments, diketopyrrolopyrrole pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, dye lakes such as basic dye lakes and acid dye lakes, nitro pigments, and nitroso pigments Organic pigments such as pigments, aniline black, and daylight fluorescent pigments. Among the above pigments, it is particularly preferable to use azo pigments, phthalocyanine pigments, anthraquinone pigments, quinacridone pigments, and carbon black pigments.

The dye that forms the J-aggregate is defined as having a λmax by forming a J-aggregate with respect to λmax in a molecular dispersion state in a solution (solvent is, for example, dimethylformamide or dimethylsulfoxide). 20nm
These are dyes that can shift to the long-wave side. For details of J-aggregates of dyes, see “Theory of Photographic Process” (TH Ja).
mes), pp. 216-222. Among the dyes forming the J-aggregate, it is preferable to use a dye having λmax different from the molecular dispersion state by 20 nm or more and 150 nm or less between the aggregate and the aggregate because the hue and color reproducibility of the formed image become better. Preferably, λ
dyes whose max differs from 30 nm to 120 nm). As the dye, any dye that forms a J-aggregate may be used, and a dye having desired absorption characteristics can be appropriately selected. For example, Handbook of Dyes (edited by The Society of Synthetic Organic Chemistry, Maruzen, published in 1978), Coloring Agent 61 [4], pp. 215 to 226 (1988)
And Chemical Industry, pp. 43-53 (198).
(June and May) Various dyes represented by the following general formulas (1) to (11) can be used.

[0016]

Embedded image

In the general formulas (1) to (11), A ¹ and A ² each represent an acidic nucleus, and A ³ represents a substituted or unsubstituted phenol, a substituted or unsubstituted naphthol, or an acidic nucleus; B ¹ represents a basic nucleus, B ² represents an onium form of the basic nucleus, Q ¹ and Q ² each independently represent an aryl group or a heterocyclic group, and Q ³ represents an aryl group or L ¹ , L ² , L ³ , L ⁴ , L ⁵ and L ⁶ each represent a methine group, m, s and u represent 0,
1, 2 and n and p represent 0, 1, 2, and 3, respectively, q
Represents 0, 1, 2, 3, 4, and r, t1 and t2 are
They represent 1 and 2, respectively. X ^y- represents an anion; y represents 1 or 2; W ¹ and W ² each independently represent an atom necessary to form a 5- or 6-membered carbocyclic or heterocyclic group; Represents a group.

The acidic nucleus represented by A ¹ , A ² or A ³ is preferably an acidic nucleus derived from a cyclic ketomethylene compound or an acidic nucleus derived from a compound having a methylene group sandwiched between electron-withdrawing groups. . Examples of the cyclic ketomethylene compound include 2-pyrazolin-5-one, rhodanin, hydantoin, thiohydantoin, 2,4-oxazolidinedione, isoxazolone, barbituric acid,
Thiobarbituric acid, indandione, dioxopyrazolopyridine, hydroxypyridine, pyrazolidinedione, 2,5-dihydrofuran-2-one, pyrrolin-2
-On. The cyclic ketomethylene compound may have a substituent.

A methylene group sandwiched between the electron-withdrawing groups
Is a compound having Z¹-CH_Two-Z ^TwoCan be represented by
You. Z¹And Z^TwoAre -CN and -SO, respectively._TwoR¹, -CO
R¹, -COOR^Two, -CONHR^Two, -SO_TwoNHR^Two,
-C [= C (CN)_Two] NHR¹It is preferred to represent R
¹Represents an alkyl group, an aryl group, or a heterocyclic group.
Then R^TwoIs a hydrogen atom, an alkyl group, an aryl group, or
It preferably represents a heterocyclic group. R¹Or R^TwoRepresented by
An alkyl group, an aryl group, or a heterocyclic group is a substituent
May be provided.

The basic nucleus represented by B ¹ is preferably pyridine, quinoline, indolenine, oxazole, imidazole, thiazole, benzoxazole, benzimidazole, benzothiazole, oxazoline, naphthoxazole pyrrole. The basic nucleus may have a substituent. B ² represents an onium of a basic nucleus which may have a substituent, and among these, the onium of a basic nucleus listed as a preferable example of B ¹ is preferable.

The aryl groups represented by Q ¹ and Q ² include:
It includes an unsubstituted aryl group and an aryl group having a substituent. As the aryl group, a phenyl group and a naphthyl group are preferable. The aryl group represented by Q ¹ preferably has a dialkylamino group, a hydroxyl group, or an alkoxy group as a substituent. The aryl group represented by Q ² preferably has an electron-withdrawing group such as a nitro group, a cyano group, a sulfonyl group, or a halogen atom as a substituent. Q
^The heterocyclic group represented by ¹ and Q ² includes an unsubstituted heterocyclic group and a substituted heterocyclic group. Specifically, pyrrole, indole, furan, thiophene, imidazole, pyrazole, indolizine, quinoline, carbazole, phenothiazine, indoline, thiazole,
Pyridine, pyridazine, thiadiazine, pyran, thiopyran, oxadiazole, benzoquinoline, thiadiazole, pyrrolothiazole, pyrrolopyridazine, tetrazole, oxazole, coumarin, and chroman are preferred.

Examples of the onium form of the aryl group or heterocyclic group represented by Q ³ include aryl groups such as a phenyl group and a naphthyl group, and the above-mentioned heterocyclic groups represented by the heterocyclic groups represented by Q ¹ and Q ^2. An onium compound in which an onium group such as a quaternary ammonium group is substituted on the ring group is exemplified. In addition, those in which a hetero atom constituting a heterocyclic ring becomes a cation to form an onium compound are also included. The aryl group and the heterocyclic group may have a substituent.

Examples of the substituent include a hydrogen atom, a hydroxyl group, a halogen atom (for example, chlorine, bromine, fluorine, iodine), a cyano group, a nitro group, a carboxyl group, a sulfo group, a chain having 1 to 8 carbon atoms. Or cyclic alkyl groups (e.g., methyl, ethyl, isopropyl, n-butyl, n-hexyl, cyclopropyl, cyclohexyl,
2-hydroxyethyl, 4-carboxybutyl, 2-methoxyethyl, 2-diethylaminoethyl), an alkenyl group having 2 to 8 carbon atoms (for example, vinyl, allyl,
-Hexenyl), an alkynyl group having 2 to 8 carbon atoms (e.g., ethynyl, 1-butynyl, 3-hexynyl), an aralkyl group having 7 to 12 carbon atoms (e.g., benzyl,
Phenethyl), an aryl group having 6 to 10 carbon atoms (eg, phenyl, naphthyl, 4-carboxyphenyl,
-Acetamidophenyl, 3-methanesulfonamidophenyl, 4-methoxyphenyl, 3-carboxyphenyl, 3,5-dicarboxyphenyl, 4-methanesulfonamidophenyl, 4-butanesulfonamidophenyl), having 1 to 10 carbon atoms (Eg, acetyl, benzoyl, propanoyl, butanoyl), an alkoxycarbonyl group having 2 to 10 carbon atoms (eg, methoxycarbonyl, ethoxycarbonyl), and a carbon atom of 7
To 12 aryloxycarbonyl groups (for example, phenoxycarbonyl, naphthoxycarbonyl), and having 1 carbon atom
10 to 10 carbamoyl groups (eg, unsubstituted carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl), C1 to C8 alkoxy groups (for example, methoxy, ethoxy, butoxy, methoxyethoxy), C6 to C6 12 aryloxy groups (for example, phenoxy, 4-carboxyphenoxy, 3-methylphenoxy, naphthoxy), an acyloxy group having 2 to 12 carbon atoms (for example, acetoxy, benzoyloxy), a sulfonyloxy group having 1 to 12 carbon atoms (Eg, methylsulfonyloxy, phenylsulfonyloxy), an amino group having 0 to 10 carbon atoms (eg, unsubstituted amino, dimethylamino, diethylamino, 2-carboxyethylamino), an acylamino group having 1 to 10 carbon atoms (For example, Toamide, benzamide), a sulfonylamino group having 1 to 8 carbon atoms (eg, methylsulfonylamino, phenylsulfonylamino, butylsulfonylamino, n-octylsulfonylamino), a ureido group having 1 to 10 carbon atoms (eg, ureido) , Methylureido), a urethane group having 2 to 10 carbon atoms (for example, methoxycarbonylamino, ethoxycarbonylamino), an alkylthio group having 1 to 12 carbon atoms (for example, methylthio, ethylthio, octylthio), 6 to 6 carbon atoms 12 arylthio groups (eg, phenylthio, nephthylthio), alkylsulfonyl groups having 1 to 8 carbon atoms (eg, methylsulfonyl, butylsulfonyl), and arylsulfonyl groups having 7 to 12 carbon atoms (eg, phenylsulfonyl, 2-phenyl) Nahchi Sulfonyl), a sulfamoyl group having a carbon number of 0-8 (e.g.,
Unsubstituted sulfamoyl, methylsulfamoyl and the like, and a heterocyclic group (for example, 4-pyridyl, piperidino, 2-furyl, furfuryl, 2-thienyl, 2-pyrrolyl, 2-quinolylmorpholino) and the like can be mentioned.

The methine groups represented by L ¹ , L ² , L ³ , L ⁴ , L ⁵ and L ⁶ include unsubstituted methine groups and substituted methine groups. Further, the substituents of the methine group may be connected to each other to form a 4, 5, 6 or 7-membered ring (for example, cyclobutene, cyclopentene, cyclohexene, cycloheptene).

The anion represented by X ^y- is represented by the general formula (7)
Represents an anion capable of supplying a negative charge necessary for neutralizing the charge of the cation in the compound represented by Preferably y is 1 or 2, ie X is a monovalent or divalent anion. The anion represented by X ^y- is Cl
^-, Br ^-, I ^- halogen ions, such as, SO ₄ ^2-, HSO
₄ ^-, CH ₃ OSO ₃ ^- alkyl sulfate ion such as p-toluenesulfonic acid ion, naphthalene-1,5-disulfonic acid ion, methanesulfonate ion, trifluoromethanesulfonate ion, ion sulfonic acids such as octanoic acid ion , Acetate ion, p-chlorobenzoate ion, trifluoroacetate ion, oxalate ion,
Carboxylate ions such as succinate ion, PF ₆ ⁻ , BF
_{^{4 -, ClO 4 -, IO}} 4 -, tungstate ion, heteropolyacids ion such as tungstophosphoric acid ions, H ₂ PO ₄
^-, NO ₃ ^-, etc. phenolate ions such as picrate ion.

W ¹ and W ² each independently represent a group of atoms necessary to form a 5- or 6-membered carbocyclic or heterocyclic group.

There are no particular restrictions on the substituents that each of the above groups may have, and specific substituents are the same as those described above.
A ¹ , A ² , A ³ ,
B ¹ , B ² , Q ¹ , Q ² , Q ³ , L ¹ , L ² , L ³ , L ⁴ , L ⁵ ,
And L ⁶ may be linked to each other to form a ring.

Specific examples of the dye forming the J-aggregate are shown below, but the dye used in the present invention is not limited to the following compounds. The cation in the formula may be any of a proton, ammonium, an organic cation (such as triethylammonium, hydroxyethylammonium, and pyridinium) and a metal cation other than those described above.

[0029]

Embedded image

[0030]

Embedded image

[0031]

Embedded image

[0032]

Embedded image

[0033]

Embedded image

[0034]

Embedded image

[0035]

Embedded image

[0036]

Embedded image

[0037]

Embedded image

[0038]

Embedded image

[0039]

Embedded image

[0040]

Embedded image

[0041]

Embedded image

[0042]

Embedded image

[0043]

Embedded image

[0044]

Embedded image

[0045]

Embedded image

[0046]

Embedded image

[0047]

Embedded image

[0048]

Embedded image

[0049]

Embedded image

[0050]

Embedded image

[0051]

Embedded image

[0052]

Embedded image

Among the dyes represented by the general formulas (1) to (11), the dyes represented by the general formulas (1), (2),
The dyes represented by (4), (5), and (6) are preferable because they can form a J-aggregate stably, and the dyes represented by the general formulas (2) and (5) are preferable. Is more preferred. Particularly preferred is a dye represented by the general formula (2).

The cyanine dye represented by the general formula (5) is described in "Theory of Photographic Process" (HJ James, 2nd Edition).
It is described on pages 16 to 222 that a J-aggregate can be formed, which is preferable as a dye of the ink of the present invention. The oxonol dye represented by the general formula (2) is also disclosed in JP-A-9-179246 and European Patent No. 778.
No. 493, U.S. Pat. Nos. 5,922,593 and 5,928.
No. 849 and No. 5965333 describe that the compounds described above can form an aggregate having a longer absorption wavelength, which is preferable as a dye of the ink of the present invention.

The dyes represented by formulas (1) to (11) are described in WO 88/04794, EP 274,723.
No., 276,556, 299,435, US
2,527,583, 3,486,897, 3,746,539, 3,933,798, 4,130,429, 4,040,841, and Nos. 48-68,623, 52-92,716, 55-155,350, 55-155,351,
No. 61-205,934, JP-A-2-173,630
No. 2-230,135 and 2-277,044
Nos. 2-282, 244, 3-7,931, 3-167,546, 3-13,937, 3-
Nos. 206,443, 3-208,047, 3-1
Nos. 92,157, 3-216,645 and 3-27
4,043, 4-37,841, 4-45,4
No. 36, No. 4-138, 449, No. 5-197, 07
No. 7, Japanese Patent Application No. 5-273, 811 and No. 6-7,761
No. 6,155,727, etc., or a method analogous thereto.

In the present invention, the water-insoluble colorant may be used alone, or a plurality of colorants may be used in combination.

-Polymer Dispersant- The polymer dispersant is a polymer compound having a dispersion-stable group in an aqueous medium and an adsorptive group adsorbed on a water-insoluble colorant. Polymer dispersants are water-insoluble, water-dispersed (self-emulsifying)
Any of a water-soluble type and a water-soluble type may be used, but a water-dispersible type is preferred in terms of ease of production and dispersion stability of the colorant-containing fine particles. The polymer dispersant may be a polymer obtained by polymerizing a monomer having both a dispersion stable group and an adsorptive group, or a polymer obtained by copolymerizing a monomer having a dispersion stable group and a monomer having an adsorptive group. It may be a polymer.
In any case, it may be copolymerized with another copolymerization monomer. Examples of the polymer dispersant include a vinyl polymer and a condensation polymer (polyurethane, polyester, polyamide, polyurea, polycarbonate).

The dispersion-stable group may be an ionic group, a non-ionic group, or a mixture thereof. The ionic group may be an anionic ionic group and a cationic ionic group, or a mixture thereof. The adsorbing group is preferably selected based on the properties of the water-insoluble colorant used. For example, for a water-insoluble colorant having almost no charge on particles, an adsorptive group due to hydrophobic interaction or aromatic ring interaction is mentioned, and specifically, an aliphatic group or an aromatic group is mentioned. . When the charge of the particles is large, groups that can have the opposite charge are mentioned. Specifically, for the surface charge of the anion, a cationic ionic group,
For the surface charge of the cation, an anionic ionic group may be used. These may be used alone or in combination of two or more.

In the present invention, in view of the ease of production of the colorant-containing fine particles and the dispersion stability, the polymer dispersant is an ion dissociation type containing an anionic ionic group and containing a nonionic dispersible group. And an ion-dissociative type containing an anionic ionic group, and a mixed type of both an anionic ionic group-containing type and a nonionic dispersible group-containing type.

The anionic ionic group includes ionic groups such as carboxylic acid, sulfonic acid and phosphoric acid.

Examples of the carboxylic acid include acrylic acid, methacrylic acid, 2-carboxyethyl acrylate, itaconic acid, maleic acid, fumaric acid, citraconic acid, crotonic acid, itaconic acid monoester, maleic acid monoester, acrylic acid Sodium, ammonium methacrylate, potassium itaconate, and the like.

Examples of the sulfonic acid include styrenesulfonic acid, vinylsulfonic acid, acryloyloxyalkanesulfonic acid (eg, acryloyloxyethanesulfonic acid, acryloyloxypropanesulfonic acid, etc.), and methacryloyloxyalkanesulfonic acid (eg, acryloyl) Oxyethanesulfonic acid, acryloyloxypropanesulfonic acid, etc.), acrylamidealkanesulfonic acid (for example, 2-acrylamide-2)
-Methylethanesulfonic acid, 2-acrylamide-2-
Methylpropanesulfonic acid, 2-acrylamide-2-
Methylbutanesulfonic acid, etc.), methacrylamide alkanesulfonic acid (eg, 2-methacrylamide-2-
Methylpropanesulfonic acid, 2-methacrylamide-2
-Methylbutanesulfonic acid, etc.).

Examples of the phosphoric acid include vinylphosphonic acid and methacryloyloxyethanephosphonic acid.

Of these, acrylic acid, methacrylic acid, styrene sulfonic acid, vinyl sulfonic acid, 2 carboxyethyl acrylate, acrylamidoalkyl sulfonic acid and methacrylamidoalkyl sulfonic acid are preferable, and acrylic acid, methacrylic acid, 2-carboxyethyl acrylate is preferable. Is more preferred.

Examples of the cationic ionic group include ionic groups having a tertiary amino group such as dialkylaminoethyl methacrylate, dialkylaminopropyl acrylate and dialkylaminopropylacrylamide, and N-2-acryloyloxy. Ethyl-N,
And ionic groups having a quaternary ammonium group such as N, N-trimethylammonium chloride and N-vinylbenzyl-N, N, N-triethylammonium chloride.

Examples of the nonionic dispersing group include sites having high hydrophilicity, that is, a group containing a polyethyleneoxy group, a group containing polyvinylpyrrolidone, a group containing a polyvinyl alcohol, and the like. For example, esters of polyethylene glycols and carboxylic acids, esters of polyethylene glycols and sulfonic acids, esters of polyethylene glycols and phosphoric acid, vinyl group-containing urethanes formed from polyethylene glycols and isocyanate groups, and polyvinyl alcohol structures And the like.

The polyethylene glycols are polyethylene glycol monoalkyl ether and polyethylene glycol having hydroxyl groups at both ends. When the polyethylene glycol is polyethylene glycol, the derived vinyl monomer preferably has a polymerizable group at only one terminal and the other terminal is a hydroxyl group.
The repeating number of the ethyleneoxy moiety of the polyethylene glycol is preferably 5 to 100, and more preferably 5 to 30. The number of carbon atoms in the alkyl group of the polyethylene glycol monoalkyl ether is from 1 to 2
0 is preferable, and 1 to 12 is more preferable.

The aliphatic group is a chain or cyclic alkyl group, alkenyl group or alkynyl group, each of which may be substituted. Examples of the substituent include an aromatic group, a halogen atom, a cyano group, a hydroxy group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, and a carbamoyl group. The aromatic group is an aryl group and may have a substituent. Examples of the substituent include the above-mentioned aliphatic group, halogen atom, cyano group, hydroxy group, alkoxy group, aryloxy group, acyl group, alkoxycarbonyl group, carbamoyl group and the like.

Examples of the above copolymerizable monomers include the following. In addition, the ester group described in the example of the comonomer represents the aliphatic group and the aromatic group.

Acrylic esters, methacrylic esters, vinyl esters of aliphatic or aromatic carboxylic acids, acrylamides and methacrylamides (specifically, acrylamide, N-monosubstituted acrylamide,
N-disubstituted acrylamide, methacrylamide, N-monosubstituted methacrylamide, N-disubstituted methacrylamide (substituents are the aliphatic groups and the aromatic groups), olefins (eg, ethylene, propylene, 1-butene) , 1
-Pentene, vinyl chloride, vinylidene chloride, isoprene, chloroprene, butadiene, 2,3-dimethylbutadiene and the like, styrenes (for example, styrene, substituted styrene) and the like. Further, vinyl ethers (specifically, the aliphatic vinyl ether, the aromatic vinyl ether),
Other monomers include acrylonitrile, methacrylonitrile, crotonic acid ester, itaconic acid diester, maleic acid diester, fumaric acid diester, methyl vinyl ketone, phenyl vinyl ketone, N-vinyl oxazolidone, N-vinyl pyrrolidone, vinylidene chloride, methylene malon Nitrile, vinylidene, etc.

Next, the condensation polymer will be described in detail. Polyurethane is basically synthesized by a polyaddition reaction using a diol compound and a diisocyanate compound as raw materials. Specific examples of the diol compound include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 2,3-butanediol, and 2,2-dimethyl as non-dissociable diols. -1,3-propanediol, 1,4-pentanediol, 2,4-pentanediol, 3,3-dimethyl-
1,2-butanediol, 2-ethyl-2-methyl-
1,3-propanediol, 1,6-hexanediol, 2,5-hexanediol, 2-methyl-2,4-
Pentanediol, 2,2-diethyl-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol, 2-methyl-2-propyl-1,3-propanediol, 2,5-dimethyl- 2,5-hexanediol, 2-ethyl-1,3-hexanediol, 1,2-
Octanediol, 2,2,4-trimethyl-1,3-
Pentanediol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol,
Dipropylene glycol, tripropylene glycol,
Polyethylene glycol (average molecular weight = 200 to 400
0), polypropylene glycol (average molecular weight = 200)
~ 1000), polyester polyol, 4,4'-dihydroxydiphenyl-2,2-propane, 4,4'-
And dihydroxyphenylsulfone.

Preferred examples of the diisocyanate include ethylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 2,4-toluene diisocyanate, 1,3-xylylene diisocyanate,
1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate,
3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, 3,3′-dimethylbiphenylene diisocyanate, dicyclohexylmethane diisocyanate,
Methylene bis (4-cyclohexyl isocyanate) and the like can be mentioned.

Incorporation of an ionic group into the polyurethane is carried out, for example, by using a diol containing an ionic group during the synthesis of the polyurethane. In that case, the ionic groups are introduced into the polyurethane as substituents from the polymer backbone. Examples of the diol having an ionic group, particularly an anionic group, include 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (hydroxymethyl) butanoic acid, and 2,5,6-trimethoxy-3,4- Dihydroxyhexanoic acid, 2,3-dihydroxy-4,5
Examples thereof include -dimethoxypentanoic acid, 3,5-di (2-hydroxy) ethyloxycarbonylbenzenesulfonic acid, and salts thereof, but are not particularly limited thereto.

The ionic group contained in the polyurethane includes a carboxyl group, a sulfonic acid group, a sulfuric acid monoester group, —OPO (OH) ₂ , a sulfinic acid group, or a salt thereof (for example, an alkali metal such as Na or K). Salt or ammonia, dimethylamine, ethanolamine,
Anionic groups such as ammonium salts such as diethanolamine, triethanolamine and trimethylamine),
Alternatively, cationic groups such as primary, secondary, tertiary amines and quaternary ammonium salts can be mentioned, among which anionic groups are preferred, and carboxyl groups are particularly preferred.

The polyester is basically synthesized by a condensation reaction between a diol compound and a dicarboxylic acid compound.
Specific examples of the dicarboxylic acid compound include oxalic acid,
Malonic acid, succinic acid, glutaric acid, dimethyl malonic acid,
Adipic acid, pimelic acid, α, α-dimethylsuccinic acid,
Acetone dicarboxylic acid, sebacic acid, 1,9-nonanedicarboxylic acid, fumaric acid, maleic acid, itaconic acid, citraconic acid, phthalic acid, isophthalic acid, terephthalic acid, 2
-Butyl terephthalic acid, tetrachloroterephthalic acid, acetylenedicarboxylic acid, poly (ethylene terephthalate) dicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, ω-poly (ethylene oxide) dicarboxylic acid, p-xylyl Examples thereof include a range carboxylic acid. When these compounds are subjected to a polycondensation reaction with a diol compound, an alkyl ester of dicarboxylic acid (for example, dimethyl ester)
It may be used in the form of acid chloride of dicarboxylic acid or dicarboxylic acid, or may be used in the form of acid anhydride such as maleic anhydride, succinic anhydride, and phthalic anhydride.

When an ionic group is contained in the polyester, a sulfonic acid group, a sulfuric acid monoester group, —OPO (OH) ₂ , a sulfinic acid group, or a salt thereof (for example, Na, K, etc.) besides carboxylic acid is used. Alkali metal salts, or ammonia, dimethylamine, ethanolamine,
Anionic groups such as ammonium salts such as diethanolamine, triethanolamine and trimethylamine),
Alternatively, a tertiary amine or a salt thereof (eg, a salt of an organic acid (eg, acetic acid, propionic acid, methanesulfonic acid) or an inorganic acid (hydrochloric acid, sulfuric acid, etc.)) or a cationic group such as a quaternary ammonium salt It can be contained by synthesis using a dicarboxylic acid compound having an ionic group. As the ionic group to be contained in the polyester, an ionic group other than the carboxylic acid is preferably an anionic group, and particularly preferably a sulfonic acid group.

A dicarboxylic acid having a sulfonic acid group,
Preferred examples of the diol raw materials include sulfophthalic acids (3-sulfophthalic acid, 4-sulfophthalic acid, 4-sulfoisophthalic acid, 5-sulfoisophthalic acid, and 2-sulfoterephthalic acid), sulfosuccinic acid, and sulfonaphthalenedicarboxylic acids (4- Sulfo-1,8-naphthalenedicarboxylic acid, 7-sulfo-1,5-naphthalenedicarboxylic acid, etc.), 3,5-di (2-hydroxy) ethyloxycarbonylbenzenesulfonic acid, and salts thereof.

As the diol compound, compounds selected from the same group as the diols described in the above polyurethane can be used. A typical synthesis method of the polyester is a condensation reaction of the above diol compound with a dicarboxylic acid or a derivative thereof, and is obtained by condensing a hydroxycarboxylic acid such as a hydroxycarboxylic acid (for example, 12-hydroxystearic acid). And ring-opening polymerization of cyclic ethers and lactones.
Polyesters obtained by a method such as ring-opening polymerization (I) written by Takeo Saegusa (detailed in Kagaku Dojin, 1971) can also be suitably used in the present invention.

The polyamide can be obtained by polycondensation of a diamine compound and a dicarboxylic acid compound, polycondensation of an aminocarboxylic acid compound, or ring-opening polymerization of lactams. As the diamine compound, ethylenediamine,
1,3-propanediamine, 1,2-propanediamine, hexamethylenediamine, octamethylenediamine, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, piperazine, 2,5-dimethylpiperazine, 4,4 ′ -Diaminodiphenyl ether, 3,3'-diaminodiphenylsulfone, xylylenediamine and the like. Examples of the aminocarboxylic acid include glycine, alanine, phenylalanine and ω-.
Examples include aminohexanoic acid, ω-aminodecanoic acid, ω-aminoundecanoic acid, and anthranilic acid. Examples of the monomer that can be used for ring-opening polymerization include ε-caprolactam, azetidinone, and pyrrolidone. As the dicarboxylic acid compound, a compound selected from the same group as the dicarboxylic acids described in the polyester can be used.

The polyurea can be obtained basically by polyaddition of a diamine compound and a diisocyanate compound or by a deammonification reaction of a diamine compound and urea.
As the diamine compound as the raw material, the diamines described in the above polyamide and the diisocyanate compound may be compounds selected from the same group as the diisocyanates described in the above polyurethane.

Polycarbonate is basically a diol compound and a phosgene or carbonate derivative (eg,
And a diol compound as a raw material, which can be a compound belonging to the same group as the diols described in the above polyurethane.

When an ionic group is introduced into the above condensation polymer, it can be introduced into each of the above polymers by various methods. For example, in the case of polyurethane, as described above, a diol containing an ionic group is used during synthesis,
It can be introduced as a substituent from the polymer main chain.
Further, as in the case of using a polyester as the oil-soluble polymer, it can be introduced by leaving a dicarboxylic acid unreacted terminal at the terminal of the polymer. Further, after the polymerization of each of the above polymers, a compound capable of introducing an ionic group by a reaction such as an acid anhydride (for example, maleic anhydride) may be allowed to act on a reactive group such as a hydroxy group or an amino group. it can.

As the polymer described above, necessary constituent materials may be used singly for both the vinyl polymer and the condensation-based polymer, and may be used for various purposes (for example, adjustment of the glass transition temperature (Tg) of the polymer or melting of the polymer). Properties, compatibility with dyes,
(Stability of dispersion), two or more of them can be used in any ratio.

In the above-mentioned polymer dispersants, in consideration of imparting excellent dispersion stability and easy introduction of ionic groups, vinyl polymers, polyurethanes and polyesters are more preferred, and vinyl polymers are particularly preferred. .

Specific Examples of the Vinyl Polymer (PP-1)
To (PP-54), (PP-75) to (PP-80) are listed below. The ratio in parentheses means the mass ratio. Note that the present invention is not limited to these specific examples.

PP-1) tert-butyl methacrylamide / butyl acrylate / acrylic acid copolymer
(60:30:30) PP-2) n-butyl acrylate / N-vinylpyrrolidone / acrylic acid copolymer (55: 40: 5) PP-3) methyl methacrylate / isobutyl methacrylate / acrylic acid copolymer (60 : 30:10) PP-4) sec-butyl acrylate / acrylic acid copolymer (90:10) PP-5) benzyl acrylate / N-acryloylmorpholine / acrylic acid (75: 20: 5) PP-6) isopropyl Acrylate / acrylic acid copolymer (90:10) PP-7) n-butyl methacrylate / 3-dimethylaminopropylacrylamide / 2-hydroxyethyl methacrylate / acrylic acid copolymer (80: 5: 5:
10)

PP-8) Isobutyl methacrylate / tetrahydrofurfuryl acrylate / acrylic acid copolymer (60:30:10) PP-9) n-butyl methacrylate / 1H, 1
H, 2H, 2H-perfluorodecyl acrylate / acrylic acid copolymer (75: 20: 5) PP-10) Methyl methacrylate / n-butyl acrylate / acrylic acid copolymer (47.5: 47.5:
5) PP-11) 2-ethylhexyl methacrylate / methyl acrylate / acrylic acid copolymer (40:55:
5) PP-12) 3-methoxybutyl methacrylate / styrene / acrylic acid copolymer (35:50:15) PP-13) Cyclohexyl methacrylate / 2-hydroxyethyl acrylate / allyl methacrylate /
Acrylic acid copolymer (50: 20: 20: 10) PP-14) Isopropyl methacrylate / 2-butoxyethyl methacrylate / acrylic acid copolymer (80:
15: 5) PP-15) Ethyl acrylate / phenyl methacrylate / acrylic acid copolymer (82: 15: 3) PP-16) Methyl methacrylate / 2-ethylhexyl acrylate / acrylic acid copolymer (47.5: 4)
7.5: 5) PP-17) Isobutyl methacrylate / Polyethylene glycol monomethyl ether (ethylene oxy chain repeating number: 23) methacrylate / acrylic acid copolymer (70: 25: 5) PP-18) Isobutyl methacrylate / Dipropylene glycol monomethacrylate / acrylic acid copolymer
(85: 10: 5) PP-19) Methacrylic acid ester / acrylic acid copolymer of isobutyl methacrylate / polyethylene glycol monomethyl ether (ethyleneoxy chain repeating number 9) (85: 10: 5)

PP-20) isobutyl acrylate /
3-dimethylaminopropylacrylamide / acrylic acid copolymer (85: 5: 10) PP-21) tert-butyl acrylate / methacrylic acid copolymer (88:12) PP-22) hexyl acrylate styrene / methacrylic acid copolymer Copolymer (80:10:10) PP-23) 2,2,2-trifluoroethyl methacrylate / methyl methacrylate / methacrylic acid copolymer (35: 60: 5) PP-24) Ethyl methacrylate / methacrylic acid copolymer (95: 5) PP-25) Ethyl methacrylate / 2-methoxyethyl methacrylate / methacrylic acid copolymer (70: 1)
5:15) PP-26) n-butyl methacrylate / methacrylonitrile / methacrylic acid copolymer (70:20:10) PP-27) vinyl acetate / methacrylic acid copolymer (85:15) PP-28 ) N-butyl methacrylate / acrylamide / methacrylic acid copolymer (80: 15: 5) PP-29) tert-octylacrylamide / propyl methacrylate methacrylic acid copolymer (20: 6)
5:15) PP-30) n-butyl methacrylate / butoxymethylacrylamide / methacrylic acid copolymer (80:
5:15) PP-31) n-butyl methacrylate / diphenyl-2-methacryloyloxyethyl phosphate / methacrylic acid copolymer (50:40:10) PP-32) isobutyl methacrylate / dimethylacrylamide / methacrylic acid Polymer (80: 15: 5) PP-33) n-butyl methacrylate / phenylacrylamide / methacrylic acid copolymer (70: 15: 1)
5)

PP-34) n-butyl methacrylate / methoxyethyl methacrylamide / methacrylic acid copolymer (70:15:15) PP-35) isobutyl methacrylate / 2- (2-
(Methoxyethoxy) ethyl methacrylate / methacrylic acid copolymer (50:35:15) PP-36) Ethyl methacrylate / 2-carboxyethyl methacrylate copolymer (90:10) PP-37) n-butyl methacrylate / styrene sulfonic acid Copolymer (90:10) PP-38) Ethyl methacrylate / styrene sulfonic acid copolymer (90:10) PP-39) n-butyl acrylate / styrene / styrene sulfonic acid copolymer (60: 35: 5) PP-40) n-butyl acrylate / 1H, 1H,
2H, 2H-perfluorodecyl methacrylate / 2-
Carboxyethyl acrylate (80:10:10) PP-41) n-butyl methacrylate / 2-acrylamido-2-methylethanesulfonic acid copolymer (9
0:10)

PP-42) isobutyl acrylate /
n-butyl methacrylate / 2-acrylamide-2-
Methylethanesulfonic acid copolymer (70:20:10) PP-43) n-butyl methacrylate / 2-acrylamido-2-methylpropanesulfonic acid copolymer (9
0:10) PP-44) Ethyl methacrylate / 2-acrylamido-2-methylpropanesulfonic acid copolymer (90:
10) PP-45) Ethyl acrylate / tert-butyl methacrylate / 2-acrylamido-2-methylpropanesulfonic acid copolymer (60: 35: 5) PP-46) tert-butyl acrylate / tetrahydrofurfuryl acrylate / 2- Methylpropanesulfonic acid copolymer (50:40:10) PP-47) Methacrylic acid ester of tert-butyl acrylate / polyethylene glycol monomethyl ether (ethyleneoxy chain repeating number: 23) / 2-acrylamido-2-methylpropane Sulfonic acid copolymer
(70: 27: 3) PP-48) Isobutyl acrylate / N-vinylpyrrolidone / 2-acrylamido-2-methylpropanesulfonic acid copolymer (65: 30: 5) PP-49) Isobutyl methacrylate / 2-acrylamide- Sodium 2-methylpropanesulfonate copolymer (88:12)

PP-50) n-butyl methacrylate / 2-methacrylamide-2-methylpropanesulfonic acid copolymer (90:10) PP-51) n-butyl acrylate / tert-butyl methacrylate vinyl sulfonic acid copolymer (60:
30:10) PP-52) Ethyl acrylate / tert-butyl methacrylate / vinyl sulfonic acid copolymer (60: 3)
0:10) PP-53) Ethyl methacrylate / 2-acrylamido-2-methylbutanesulfonic acid copolymer (90: 1)
0) PP-54) n-butyl methacrylate / mono-2-methacryloyloxyethyl phthalate copolymer (88: 1)
2)

PP-75) Poly-N-vinylpyrrolidone PP-76) N-vinylpyrrolidone / benzyl methacrylate copolymer (90:10) PP-77) N-vinylacetamide / benzyl acrylate copolymer (85:15) PP-78) N-vinylpyrrolidone / naphthyl acrylate copolymer (90:10) PP-79) Polybenzyl methacrylate-graft-
Poly N-vinyl pyrrolidone (copolymer mass ratio 60:40,
Side chain molecular weight 4000) PP-80) Poly (butyl acrylate-CO-benzyl methacrylate) -graft-polyethylene oxide (copolymerization mass ratio 50:20:30, side chain molecular weight 200)
0)

Specific examples (PP-55) to (PP-74) of the condensation polymer among the above-mentioned polymer dispersants are listed below, but the present invention is not limited thereto. All acidic groups in each polymer are shown in non-dissociated form. Regarding those produced by condensation reaction such as polyester and polyamide, the constituent components are all expressed by dicarboxylic acid, diol, diamine, hydroxycarboxylic acid, aminocarboxylic acid and the like irrespective of the raw material. The ratio in parentheses means the molar percentage ratio of each component.

PP-55) 4,4'-diphenylmethane diisocyanate / hexamethylene diisocyanate /
Tetraethylene glycol / ethylene glycol / 2,2
-Bis (hydroxymethyl) propionic acid (40/10 /
20/20/10) PP-56) 4,4'-diphenylmethane diisocyanate / hexamethylene diisocyanate / butanediol / polyethylene glycol (Mw = 400) / diethylenetriamine / 2,2-bis (hydroxymethyl) propionic acid (40/10 / 20/10/5/15) PP-57) 1,5-Naphthylene diisocyanate /
Butanediol / 4,4'-dihydroxy-diphenyl-
2,2'-propane / polypropylene glycol (Mw =
400) / 2,2-bis (hydroxymethyl) propionic acid (50/20/5/10/15) PP-58) 1,5-naphthylene diisocyanate /
Hexamethylene diisocyanate / 2,2-bis (hydroxymethyl) butanoic acid / polybutylene oxide (Mw = 5
00) (35/15/25/25) PP-59) isophorone diisocyanate / diethylene glycol / neopentyl glycol / 2,2-bis (hydroxymethyl) propionic acid (50/20/20/1)
0) PP-60) Toluene diisocyanate / 2,2-bis (hydroxymethyl) butanoic acid / polyethylene glycol (Mw = 1000) / cyclohexanedimethanol (50/10/10/30) PP-61) Diphenylmethane diisocyanate / hexamethylene Diisocyanate / tetraethylene glycol / butanediol / 3,5-di (2-hydroxy) ethyloxycarbonylbenzene sulfonic acid (40/10 /
10/33/7) PP-62) Diphenylmethane diisocyanate / hexamethylene diisocyanate / butanediol / ethylene glycol / 2,2-bis (hydroxymethyl) butanoic acid / 3,5-di (2-hydroxy) ethyloxycarbonylbenzenesulfone Acid (40/10/20/15/10
/ 5)

PP-63) Terephthalic acid / isophthalic acid / 5-sulfoisophthalic acid / ethylene glycol / neopentyl glycol (24/24/2/25/25) PP-64) Terephthalic acid / isophthalic acid / 5-sulfoisophthalate Acid / cyclohexanedimethanol / 1,4-butanediol / ethylene glycol (22/22/6/25
/ 15/10) PP-65) isophthalic acid / 5-sulfoisophthalic acid /
Cyclohexanedimethanol / ethylene glycol (4
0/10/40/10) PP-66) cyclohexanedicarboxylic acid / isophthalic acid / 3,5-di (2-hydroxy) ethyloxycarbonylbenzenesulfonic acid / cyclohexanedimethanol / ethylene glycol (30/20/5/25 / 20)

PP-67) 11-aminoundecanoic acid (100) PP-68) 12-aminododecanoic acid (100) PP-69) Reaction product of poly (12-aminododecanoic acid) and maleic anhydride PP-70 ) 11-aminoundecanoic acid / 7-aminoheptanoic acid (50/50) PP-71) hexamethylenediamine / adipic acid (50/50) PP-72) N, N-dimethylethylenediamine / adipic acid / cyclohexanedicarboxylic acid ( 50/20/3
0)

PP-73) Toluene diisocyanate
/ Hexamethylenediamine / 2,2-bis (hydroxymethyl) propionic acid (50/40/10) PP-74) 11-aminoundecanoic acid / hexamethylenediamine / urea (33/33/33)

Regarding the synthesis of the above-mentioned condensation polymer,
"Polymer Experimental Studies (Vol.5) Polycondensation and Polyaddition
Published by Kyoritsu Shuppan Co., Ltd. (1980)), "Polyester Resin Handbook (Eiichiro Takiyama, published by Nikkan Kogyo Shimbun)
8)), "Polyurethane Resin Handbook (edited by Keiji Iwata, published by Nikkan Kogyo Shimbun (1987))", "Experimental Methods for Polymer Synthesis (Takashi Otsu and Masayoshi Kinoshita, co-authored by Kagaku Dojin (197)
2)) ", JP-B No. 33-1141, 37-7641
Nos. 39-5989, 40-27349, 4
Nos. 2-5118, 42-24194, 45-10
No. 957, No. 48-25435, No. 49-36942
No. 52-81344, JP-A-56-88454.
And known methods described in each gazette such as JP-A-6-340835.

The content of the ionic group in the polymer dispersant is preferably from 0.2 to 4.0 mmol / g, more preferably from 0.3 to 3.0 mmol / g. It is particularly preferred that the concentration is from 0.5 to 2.0 mmol / g. If the content of the ionic group is too small, the dispersion stability of the colorant-containing fine particles deteriorates, and if it is too large, the water solubility increases, and the suitability for production of the colorant-containing fine particles decreases. When the polymer dispersant contains an anionic ionic group, an alkali metal ion (for example, Na
⁺ , K ⁺ ) and ammonium ions.

The molecular weight (mass average molecular weight) of the polymer dispersant is preferably from 1,000 to 200,000,
More preferably from 2000 to 100,000,
More preferably, it is from 4000 to 80,000,
Particularly preferred is 50,000. Molecular weight 1000
If it is smaller, it tends to be difficult to obtain a stable dispersion. If it is larger than 200,000, the solubility in a dispersion medium is reduced, and the suitability for producing the colorant-containing fine particles is undesirably reduced.

The glass transition temperature of the polymer dispersant is-
It is preferably from 50 ° C to 150 ° C, and -30 ° C
The temperature is more preferably from 110 ° C to 110 ° C, and particularly preferably from -10 ° C to 100 ° C. Here, the glass transition temperature is a value obtained by measuring the polymer dispersant with DCS at a temperature change of 10 ° C./min. When the glass transition temperature is less than -50 ° C, the printing surface is sticky or the gas permeability is high, so that the color fading to an oxidizing gas such as ozone tends to be poor. When the glass transition temperature is higher than 150 ° C, This is not preferable because the gloss of the printed matter is inferior and the scratch resistance tends to deteriorate.

Next, an example of a method for producing a polymer dispersant will be described.
The present invention is not limited to this production example. In the following, “parts” indicates “parts by mass”. <Production Example> 148.5 parts of n-butyl acrylate, N-
108 parts of vinylpyrrolidone, 13.5 parts of acrylic acid, 2
-1.48 parts of mercaptoethanol, dimethyl 2,2 '
0.80 parts of azobis (2-methylpropionate),
A mixed solution consisting of 100 parts of IPA was prepared. Next, I
PA 35 parts, MEK 135 parts, dimethyl 2,2'-
0.20 parts of azobis (2-methylpropionate) was charged into a flask and stirred at 80 ° C. under a nitrogen seal.
The mixture was dropped over 3 hours, and after the dropping, 0.2 parts of dimethyl 2,2′-azobis (2-methylpropionate) was added.
Allowed to react for hours. The obtained polymer solution was concentrated under reduced pressure to obtain 272 parts of a target vinyl polymer PP-2. The weight average molecular weight was 21,100 (GPC, PS conversion).

-Preparation of Colorant-Containing Fine Particles- The colorant-containing fine particles of the present invention are produced by co-precipitating both from a mixed solution of a water-insoluble colorant and a polymer dispersant. Specifically, by mixing an organic solvent phase containing a water-insoluble colorant and a polymer dispersant with an aqueous phase, or by mixing the aqueous phase with an organic solvent phase containing a water-insoluble colorant and a polymer dispersant. Manufactured. When the polymer dispersant has an ionic group, all or a part of the ionic group of the polymer dispersant may be neutralized and dissolved in an organic solvent phase in advance, or the ionic group may be dissolved. It may be dissolved in an organic solvent phase without being neutralized. When the ionic group is dissolved in the organic solvent phase without being neutralized, an acid or a base for neutralizing all or a part of the ionic group of the polymer dispersant may be added to the aqueous phase. preferable. When fine particles are produced by mechanically crushing a pigment, not only the type and amount of the dispersant, the dispersion method, but also the primary particle size and surface treatment of the raw material are greatly affected, and particularly less than 100 nm. It is often difficult to obtain a fine dispersion of The use of the co-precipitation technique has the advantage that fine particles of less than 100 nm can be easily obtained without being affected by the primary particle size or surface treatment of the raw material.

The organic solvent used for producing the colorant-containing fine particles is preferably one in which both the water-insoluble colorant and the polymer dispersant are dissolved. If the amount is insufficient, a base or an acid may be added and dissolved. The organic solvent preferably has a solubility in water of 20 or more at 20 ° C., and more preferably can be mixed with water at an arbitrary ratio. For example,
Amide solvents such as dimethylformamide and dimethylacetamide; ketone solvents such as methyl ethyl ketone; alcohol solvents such as methanol, ethanol, 2-propanol, 1-propanol and tert-butanol; chlorine solvents such as chloroform and methylene chloride; benzene ,
Aromatic solvents such as toluene, ethyl acetate, butyl acetate,
Examples include ester solvents such as isopropyl acetate and dimethyl sulfoxide, ether solvents such as tetrahydrofuran and dioxane, and glycol ethers such as ethylene glycol monomethyl ether and ethylene glycol dimethyl ether. These organic solvents may be used alone or in combination of two or more.

The amount of the organic solvent used is not particularly limited, but is preferably 1 to 100 parts by mass of the water-insoluble colorant.
The amount is preferably from 0 to 2,000 parts by mass, more preferably from 100 to 1,000 parts by mass. When the amount of the organic solvent is less than 10 parts by mass, the fine and stable dispersion of the colorant-containing fine particles tends to be difficult, and when it exceeds 2,000 parts by mass,
The steps of desolvation and concentration for removing the organic solvent are indispensable, and there is a tendency that there is no room for formulation design.

When the solubility of the organic solvent in water is 20 or less, or when the vapor pressure of the organic solvent is higher than water, a part of the organic solvent or Preferably, all are removed. The removal of the organic solvent is preferably performed by evaporation or ultrafiltration.

In the colorant-containing fine particles, the amount of the polymer dispersant used may be in the range of the water-insoluble colorant 100
10 to 1000 parts by mass, preferably 20 parts by mass,
-600 parts by mass is more preferable, and 30-400 parts by mass is particularly preferable. When the amount of the polymer dispersant is less than 10 parts by mass, the stability of the dispersion tends to be poor, and the desired effects (improvement of color and bronze) tend to be poor.
If the amount is more than 10 parts by mass, the proportion of the water-insoluble colorant in the colorant-containing fine particles is reduced, and there is a tendency that there is no room for formulation design when the colorant-containing fine particles are used as an aqueous ink.

The content of the water-insoluble colorant in the ink is preferably from 0.2 to 10% by mass, more preferably from 0.5 to 30% by mass.
% By mass is more preferable, and 0.5 to 10% by mass is particularly preferable. The average particle diameter of the colorant-containing fine particles is 1 to
500 nm is preferable, 3 to 300 nm is more preferable, furthermore, 5 to 150 nm is preferable, and 5 to 100 nm.
Is particularly preferred. The average particle size can be adjusted by centrifugation, filtration, or the like.

-Water-Soluble Organic Solvent- The ink of the present invention contains a water-soluble organic solvent for the purpose of a dispersion medium for preparing the above-mentioned colorant-containing fine particles or a drying inhibitor or a penetration enhancer.

As the water-soluble organic solvent used in the present invention, a water-soluble organic solvent having a lower vapor pressure than water is preferable.
Specific examples include ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, thiodiglycol, dithiodiglycol, 2-methyl-1,3-propanediol, 1,2,6-hexanetriol, acetylene glycol derivatives, glycerin , Polyhydric alcohols represented by trimethylolpropane, etc., ethylene glycol monomethyl (or ethyl)
Lower alkyl ethers of polyhydric alcohols such as ether, diethylene glycol monomethyl (or ethyl) ether, triethylene glycol monoethyl (or butyl) ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2 -Imidazolidinone, N-
Examples include heterocycles such as ethyl morpholine, sulfur-containing compounds such as sulfolane, dimethyl sulfoxide, and 3-sulfolene, and polyfunctional compounds such as diacetone alcohol and diethanolamine. Of these, polyhydric alcohols such as glycerin and diethylene glycol are more preferred. The above-mentioned water-soluble organic solvents may be used alone or in combination of two or more. These water-soluble organic solvents are preferably contained in the ink in an amount of 10 to 50% by mass.

-Other Additives- As additives other than the water-soluble organic solvent, an anti-drying agent for preventing clogging due to drying operation at the ink ejection port, and an additive for facilitating the penetration of the ink into paper. Additives such as penetration enhancers, antioxidants, viscosity regulators, surface tension regulators, dispersants, dispersion stabilizers, fungicides, rust inhibitors, pH regulators, defoamers, chelating agents, and ultraviolet absorbers Can be appropriately selected and used in an appropriate amount.

Examples of the anti-drying agent include urea derivatives other than the water-soluble organic solvents. As the penetration enhancer, other than the water-soluble organic solvent, an anionic surfactant such as sodium lauryl sulfate and sodium oleate, a nonionic surfactant and the like can be used.
These have sufficient effects when contained in the ink in an amount of 10 to 30% by mass, and are preferably used within the range of an addition amount that does not cause printing bleeding or paper loss (print-through).

As the antioxidant used for improving the storability of the image, various organic and metal complex-based antifading agents can be used. Hydroquinones, alkoxyphenols,
Examples include dialkoxyphenols, phenols, anilines, amines, indans, chromans, alkoxyanilines, heterocycles, and the like, and metal complexes include nickel complexes and zinc complexes. More specifically, Research Disclosure No. No. 17643, Nos. VII, I to J; 15162; No. 18716, page 650, left column, ibid. Page 527 of 36544, N
o. No. 307105, page 872; The compounds described in the patent cited in US Pat.
No. 272, pages 127 to 137, the general formulas of typical compounds and the compounds included in the compound examples can be used.

Examples of the surface tension modifier include nonionic, cationic and anionic surfactants. For example, as anionic surfactants, fatty acid salts, alkyl sulfate salts, alkyl benzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinates,
Examples thereof include alkyl phosphate ester salts, naphthalene sulfonic acid formalin condensate, and polyoxyethylene alkyl sulfate salts. Examples of nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, and polyoxyethylene alkyl allyl ether. Examples thereof include an ethylene fatty acid ester, a sorbitan fatty acid ester, a polyoxyethylene sorbitan fatty acid ester, a polyoxyethylene alkylamine, a glycerin fatty acid ester, and an oxyethyleneoxypropylene block copolymer. SURFYNOLS, an acetylene-based polyoxyethylene oxide surfactant (Air
Products & Chemicals) are also preferably used. Further, amine oxide type amphoteric surfactants such as N, N-dimethyl-N-alkylamine oxide are also preferable. Further, Japanese Patent Application Laid-Open No. 59-157,636, pages (37) to (38), Research Disclosure No.
308119 (1989) may be used as the surfactant. The surface tension of the ink of the present invention is 20 to 60 m with or without these.
N / m is preferred. Furthermore, 25 to 45 mN / m is preferable.

The viscosity of the ink of the present invention is preferably 30 mPa · s or less. The viscosity is more preferably adjusted to 20 mPa · s or less, and a viscosity modifier may be used for the purpose of adjusting the viscosity. Examples of the viscosity modifier include water-soluble polymers such as celluloses and polyvinyl alcohol, and nonionic surfactants.

The fungicides used in the present invention include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, ethyl p-hydroxybenzoate, 1,2-benzisothiazoline-3-
And its salts. These are preferably used in the ink in an amount of 0.02 to 5.00% by mass. still,
Details of these are described in "Encyclopedia of Bacterial and Fungicides" (edited by the Japanese Society of Bacteria and Fungi).

Examples of the rust preventive used in the present invention include acid sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite, benzotriazole and the like. These are preferably used in the ink in an amount of 0.02 to 5.00% by mass.

The pH adjuster used in the present invention can be suitably used in terms of pH adjustment of the colorant-containing fine particle dispersion, imparting dispersion stability, etc., and has a pH of 4.5 to 10.0. , And more preferably, so as to have a pH of 6 to 10.0. As the pH adjuster, organic bases, inorganic alkalis and the like as basic ones,
Examples of acidic substances include organic acids and inorganic acids. Examples of the organic base include triethanolamine, diethanolamine, N-methyldiethanolamine, dimethylethanolamine and the like. Examples of the inorganic alkali include hydroxides of alkali metals (eg, sodium hydroxide, lithium hydroxide, potassium hydroxide, etc.), carbonates (eg, sodium carbonate, sodium hydrogen carbonate, etc.), and ammonia. In addition, examples of the organic acid include acetic acid, propionic acid, trifluoroacetic acid, and alkylsulfonic acid. Examples of the inorganic acid include hydrochloric acid, sulfuric acid, and phosphoric acid.

Fluoro- and silicone-based compounds as antifoaming agents and compounds represented by EDTA as chelating agents can be used as required.

As the ultraviolet absorber, JP-A-58-185
677, 61-90537, and JP-A-Hei 2
-782, 5-97075, 9-3
Benzotriazole compounds described in JP-A No. 4057, JP-A-46-2784, JP-A-5-194.
No. 483, U.S. Pat. No. 3,214,463, benzophenone-based compounds described in JP-B-48-30492.
JP-A-56-21141, JP-A-10-88
No. 106, etc., cinnamic acid-based compounds,
-298503 and 8-53427, 8
-239368, 10-182621,
The triazine compounds described in JP-T-8-501291 and the like, Research Disclosure No. 242
Compounds described in No. 39 and compounds emitting fluorescent light by absorbing ultraviolet light, represented by stilbene-based and benzoxazole-based compounds, so-called fluorescent whitening agents can also be used.

The ink of the present invention can be used not only for forming a single-color image but also for forming a full-color image. Magenta color ink,
A cyan color ink and a yellow color ink can be used, and a black color ink may be further used to adjust the color tone. It is preferable that at least one of these inks of various hues is the ink of the present invention, since a full-color image with good hue can be formed.
Further, it is more preferable that all the inks of these various hues are the inks of the present invention, since a full-color image having an excellent hue can be formed.

-Image-Receiving Material- Examples of the image-receiving material used in the ink jet recording method using the ink of the present invention include plain paper, coated paper, plastic film and the like. It is preferable to use coated paper as the image receiving material because image quality and image storage durability are improved.

The ink of the present invention is a known recording material, that is, plain paper, resin-coated paper, for example, JP-A-8-169172, JP-A-8-27693, JP-A-2-276670, and JP-A-7-276789. Gazette, pp. 9-323475
JP-A-62-238783, JP-A-10-153
Nos. 989, 10-217473, 10-
No. 235995, No. 10-337947, No. 10-217597, No. 10-337947, etc. Ink-jet dedicated paper, film, electrophotographic paper, fabric, glass, metal, ceramic, etc. It can be used to form images.

The recording paper and recording film used for ink-jet printing using the ink of the present invention will be described below. Supports for recording paper and film are chemical pulp such as LBKP and NBKP, GP, P
Consists of mechanical pulp such as GW, RMP, TMP, CTMP, CMP and CGP, waste paper pulp such as DIP, etc., and if necessary, conventionally known pigments, binders, sizing agents, fixing agents, cationic agents, and paper strength And various additives such as a fourdrinier paper machine, a round paper machine, etc., into which an additive such as an agent is mixed can be used. In addition to these supports, any of synthetic paper and plastic film sheets may be used. The support has a thickness of 10 to 250 μm and a basis weight of 10 to 250 g / m.
² is preferred. The support may be provided with an image receiving layer and a back coat layer as they are, or after providing a size press or an anchor coat layer with starch, polyvinyl alcohol or the like, and then providing the image receiving layer and the back coat layer. Further, the support may be subjected to a flattening treatment by a calender device such as a machine calender, a TG calender, and a soft calender. In the present invention, as the support, paper and plastic films laminated on both sides with a polyolefin (eg, polyethylene, polystyrene, polyethylene terephthalate, polybutene and copolymers thereof) are more preferably used. It is preferable to add a white pigment (eg, titanium oxide, zinc oxide) or a coloring dye (eg, cobalt blue, ultramarine, neodymium oxide) to the polyolefin polyolefin.

The image receiving layer provided on the support contains a pigment and an aqueous binder. As the pigment, a white pigment is preferable, and as the white pigment, calcium carbonate, kaolin, talc, clay, diatomaceous earth, synthetic amorphous silica, aluminum silicate, magnesium silicate, calcium silicate, aluminum hydroxide, alumina, lithopone, zeolite,
Examples thereof include inorganic white pigments such as barium sulfate, calcium sulfate, titanium dioxide, zinc sulfide, and zinc carbonate; and organic pigments such as styrene pigment, acrylic pigment, urea resin, and melamine resin. As the white pigment contained in the image receiving layer, a porous inorganic pigment is preferable, and synthetic amorphous silica having a large pore area is particularly preferable. As the synthetic amorphous silica, both silicic anhydride obtained by a dry production method and hydrous silicic acid obtained by a wet production method can be used, and it is particularly preferable to use hydrous silicic acid. Two or more of these pigments may be used in combination.

Examples of the aqueous binder contained in the image receiving layer include polyvinyl alcohol, silanol-modified polyvinyl alcohol, starch, cationized starch, casein, gelatin, carboxymethylcellulose, hydroxyethylcellulose, polyvinylpyrrolidone, polyalkylene oxide, polyalkylene oxide derivative and the like. And a water-dispersible polymer such as styrene-butadiene latex and acrylic emulsion.
These aqueous binders can be used alone or in combination of two or more. In the present invention, among these, polyvinyl alcohol and silanol-modified polyvinyl alcohol are particularly preferable in terms of adhesion to the pigment and peel resistance of the image receiving layer.

The image receiving layer can contain a mordant, a water-proofing agent, a light-fastness improver, a surfactant, a hardener and other additives in addition to the pigment and the aqueous binder.

The mordant added to the image receiving layer is preferably immobilized. For this purpose, a polymer mordant is preferably used. Polymer mordants are described in JP-A-48-28325, JP-A-54-74430, and JP-A-48-43030.
Nos. 4-124726, 55-22766, 55-
Nos. 142339, 60-23850, 60-23
No. 851, No. 60-23852, No. 60-23853
No. 60-57836, No. 60-60643, No. 60-118834, No. 60-122940, No. 6
Nos. 0-122941, 60-122942, 60
-235134, JP-A-1-161236, U.S. Pat. Nos. 2,484,430 and 2,548,564,
No. 3148061, No. 3309690, No. 4115
No. 124, No. 4124386, No. 4193800,
No. 4238353, No. 4282305, No. 4450
No. 224 is described in each specification. JP-A-1-1612
An image receiving material containing a polymer mordant described on pages 212 to 215 of JP-A No. 36 is particularly preferred. When the polymer mordant described in the publication is used, an image having excellent image quality is obtained, and the light fastness of the image is improved.

The water-proofing agent is effective for making the image waterproof.
As these waterproofing agents, cationic resins are particularly desirable. Examples of such a cationic resin include polyamide polyamine epichlorohydrin, polyethylene imine, polyamine sulfone, dimethyl diallyl ammonium chloride polymer, cationic polyacrylamide, colloidal silica, and the like. Among these cationic resins, polyamide polyamine epichlorohydrin is particularly preferable. is there. The content of these cationic resins is preferably from 1 to 15% by mass, and particularly preferably from 3 to 10% by mass, based on the total solid content of the image receiving layer.

Examples of the light resistance improver include zinc sulfate, zinc oxide, hindered amine antioxidants, and benzophenone and benzotriazole ultraviolet absorbers. Of these, zinc sulfate is particularly preferred.

Surfactants include coating aids, release improvers,
It functions as a slipperiness improver or an antistatic agent. The surfactants are described in JP-A Nos. 62-173463 and 62-183457. An organic fluoro compound may be used instead of the surfactant. Preferably, the organic fluoro compound is hydrophobic. Examples of the organic fluoro compound include a fluorinated surfactant, an oily fluorinated compound (eg, fluorinated oil), and a solid fluorinated compound resin (eg, an ethylene tetrafluoride resin).
About the organic fluoro compound, Japanese Patent Publication No. 57-9053
No. (columns 8 to 17), JP-A No. 61-20994, 6
It is described in each gazette of 2-135826.

As the hardener, the materials described on page 222 of JP-A-1-161236 can be used.

Other additives to be added to the image receiving layer include a pigment dispersant, a thickener, an antifoaming agent, a dye, a fluorescent whitening agent,
Preservatives, pH adjusters, matting agents, hardening agents and the like can be mentioned. The image receiving layer may be a single layer or two layers.

The recording paper and the recording film may be provided with a back coat layer, and the components that can be added to this layer include a white pigment, an aqueous binder and other components. Examples of the white pigment contained in the back coat layer include light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, and aluminum silicate. , Diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica,
White inorganic pigments such as colloidal alumina, pseudoboehmite, aluminum hydroxide, alumina, lithopone, zeolite, hydrohaloysite, magnesium carbonate, magnesium hydroxide, styrene plastic pigment, acrylic plastic pigment, polyethylene, microcapsules, urea resin, melamine Organic pigments such as resins are exemplified.

As the aqueous binder contained in the back coat layer, styrene / maleate copolymer, styrene / acrylate copolymer, polyvinyl alcohol, silanol-modified polyvinyl alcohol, starch, cationized starch, casein, gelatin And water-soluble polymers such as carboxymethylcellulose, hydroxyethylcellulose and polyvinylpyrrolidone, and water-dispersible polymers such as styrene-butadiene latex and acrylic emulsion. Other components contained in the back coat layer include an antifoaming agent, an antifoaming agent, a dye, a fluorescent whitening agent, a preservative, and a waterproofing agent.

A polymer latex may be added to the constituent layers (including the back layer) of the ink jet recording paper and the recording film. Polymer latex is dimensionally stable,
It is used for the purpose of improving film physical properties such as curling prevention, adhesion prevention and film cracking prevention. Polymer latex is described in JP-A-62-245258 and JP-A-62-1100.
No. 66 describes each of the publications. When a polymer latex having a low glass transition temperature (40 ° C. or lower) is added to the layer containing a mordant, cracking and curling of the layer can be prevented. Also, curling can be prevented by adding a polymer latex having a high glass transition temperature to the back layer.

The ink-jet recording method using the ink of the present invention is not limited, and a known method, for example, a charge control method for discharging ink by using electrostatic attraction, a drop-on-demand method using vibration pressure of a piezo element. (Pressure pulse method), Acoustic ink jet method in which an electric signal is converted into an acoustic beam, and the ink is emitted to irradiate the ink using a radiation pressure, and thermal which uses the pressure generated by heating the ink to form bubbles. Used for an ink jet (bubble jet (registered trademark)) system or the like. The ink jet recording method uses a method of ejecting a large number of low-density inks called photo inks in a small volume, a method of improving the image quality by using a plurality of inks having substantially the same hue and different densities, or a colorless transparent ink. The method is included.

[0138]

EXAMPLES The present invention will be described below in detail with reference to examples, but the embodiments of the present invention are not limited thereto.

Example 1 <Preparation of Ink 01> Colorant (J-associated dye 2-20)
A solution is prepared by dissolving 2.0 g of the polymer (PP-2) 2.0 g in dimethylformamide 10 g. The dissolved liquid was added dropwise to a mixture of 89 g of water and 1.16 g of a 10 w / v% aqueous sodium hydroxide solution little by little while stirring to prepare a colorant-containing fine particle dispersion. 1000 g of water was added to the obtained dispersion, and ultrafiltration was performed until 1000 g of the liquid flowed out. This was repeated three times, and then filtered with a 0.4 μm filter. The particle size of this dispersion was measured using Honeywell M
The volume average particle size was 85 nm as measured by icrotrac UPA150. Using this dispersion, an ink (ink 01) having the following composition was prepared. The above dispersion 12.5 g Ethylene glycol 1.3 g Glycerin 1.3 g Water Total amount of 25 g

<Preparation of Inks 02 to 06>
Ink Nos. 02 to 06 were similarly prepared using the same amount of compound as in the preparation of Ink 01, except that the coloring agent and the polymer were replaced by the compounds in Table 1 in Preparation 1.

[0141]

[Table 1]

-Image Recording and Evaluation- The prepared inks 01 to 06 are filled in a cartridge of an ink jet printer PM-770C (manufactured by EPSON), and plain paper for PPC and ink jet paper glossy paper are used by using the same machine. An image was recorded on EX (manufactured by Fuji Photo Film Co., Ltd.), and the following evaluation was performed. Table 2 shows the evaluation results.

<Evaluation of Printing Performance> After setting the cartridge in the printer and confirming the ejection of ink from all the nozzles, an image was output on five A4 sheets, and the printing disorder was evaluated according to the following criteria. A: There was no printing disorder from the start to the end of printing. B: Printing disorder sometimes occurred from the start to the end of printing. C: Printing disorder was observed from the start to the end of printing.

<Evaluation of Paper Dependency> The color tone of the image formed on the photo glossy paper and the image formed on the plain paper for PPC were compared. The evaluation was made in three steps, where B was small when C was small, and C when the difference between the two images was large.

<Evaluation of Color Tone> The color tone of the image formed on the photo glossy paper was visually observed, and was evaluated on a three-point scale, with A being excellent, B being good, and C being poor.

<Evaluation of Water Resistance> The photo glossy paper on which the image was formed was dried for 1 hour at room temperature, immersed in water for 30 seconds, dried naturally at room temperature, and observed for bleeding. A sample without bleeding was evaluated as A, a sample with slight bleeding as B, and a sample with much bleeding as C.

<Evaluation of Scratch Resistance> The photo glossy paper on which the image was formed was dried at room temperature for 1 hour and at 80 ° C. for 1 minute, rubbed five times with a plastic eraser, and observed discoloration.
A sample having little discoloration was evaluated as A, B having discoloration but hardly seeing a white background as B, and C showing discoloration and having a lot of white background as C.

<Dark Heat Fastness> The photo glossy paper on which the image was formed was stored at 80 ° C. and 15 RH% for 7 days.
The image density before and after storage was measured using a reflection densitometer (X-Rite310TR), and evaluated as a dye residual ratio. The dye remaining rate was evaluated at three points where the reflection density was 1, 1.5, and 2. When the dye remaining rate was 90% or more at any density, A2
The case where the point was less than 90% was B, and the case where all the points were less than 90% was C.

[0149]

[Table 2]

(Comparative Example 1) Ink 01 of Example 1 was prepared in the same manner as in Ink 01 except that no polymer was used.
Was prepared (Table 1). Using this, printing was performed in the same manner as in Example 1.

As is clear from the results shown in Table 2, the inks of the examples are excellent in printing performance, and exhibit the same performance as water resistance and dark heat fastness. Compared with the ink of the comparative example, it is particularly excellent in paper dependency, color tone, and scratch resistance.

Example 2 <Preparation of Ink 08> 1.0 g of dimethylquinacridone
To a mixture of 1.5 g of the polymer (PP-76) and 45 g of dimethyl sulfoxide, 0.5 g of potassium hydroxide and 5 g of water
Was added little by little with stirring to prepare a solution in which dimethylquinacridone and the polymer (PP-76) were uniformly dispersed. This solution was gradually dropped while being ultrasonically dispersed in 200 g of water to prepare a colorant-containing fine particle dispersion. 500 g of water was added to the obtained dispersion, and ultrafiltration was performed until 500 g of the liquid flowed out. After repeating this twice, 200 g of water was further added, and ultrafiltration was performed until 400 g of the liquid was flown out. Was filtered. The particle size of this dispersion was measured by Honeywell Microtrac UPA150.
As a result, the volume average particle size was 20 nm.
Using this dispersion, an ink (ink 08) having the following composition was prepared. The above dispersion 20.0 g Ethylene glycol 2.5 g Glycerin 2.5 g One-terminal 2-butyloctanoate of polyethylene glycol (average ethylene oxide repetition number: 12) 0.25 g

<Preparation of Inks 09 to 16>
Ink Nos. 09 to 16 were each prepared in the same manner as in the preparation of Ink 08, except that the polymers and the amounts used were changed to the compounds shown in Table 3 in Preparation of Ink 8.

[0154]

[Table 3]

-Image Recording and Evaluation- The produced inks 09 to 16 were evaluated in the same manner as in Example 1.

[0156]

[Table 4]

(Comparative Example 2) The same procedure as in Ink 09 of Example 2 was carried out except that no polymer was used. As a result, the aggregation was remarkable and no ink was obtained.

As is clear from the results shown in Table 4, the inks of the Examples have a small particle size, are excellent in printability, do not depend on paper, are excellent in color development, color tone, and water resistance, and are particularly resistant to abrasion. Was excellent.

[0159]

According to the ink of the present invention, the occurrence of clogging at the nozzle tip during image recording is suppressed, and the color developability, particularly the color tone (hue), when printing on arbitrarily selected paper without paper dependence is improved. Excellent, excellent ink penetration into photographic quality paper,
It is excellent in water resistance and light resistance after recording, and can record high-density and high-quality images.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Junichi Yamanouchi 210 Nakanakanuma, Minamiashigara-shi, Kanagawa Prefecture Fuji Photo Film F-term (reference) 2C056 EA05 EA13 EA20 FC02 2H086 BA01 BA02 BA15 BA21 BA33 BA53 BA55 BA59 4J039 AD00 AE04 AE06 AE08 BD04 BE01 BE02 BE12 CA03 CA06 EA29 EA35 EA36 EA38 EA41 EA44 EA45 GA24

Claims (3)

[Claims] 1. An ink containing at least water, a water-soluble organic solvent, and colorant-containing fine particles, wherein the colorant-containing fine particles are produced by co-precipitating a water-insoluble colorant and a polymer dispersant. An ink characterized by the following. 2. A method for producing an ink containing at least water, a water-soluble organic solvent, and colorant-containing fine particles,
A method for producing an ink, wherein the colorant-containing fine particles are produced by co-precipitating a water-insoluble colorant and a polymer dispersant, and then using a dispersion medium. 3. An ink-jet image forming method, wherein an image is formed using an ink according to claim 1, using an image receiving paper having an image receiving layer containing white inorganic pigment particles on a support.