JP5608514B2 - Method for producing water-based pigment dispersion, water-based pigment dispersion, and water-based ink for inkjet recording - Google Patents

Description

  The present invention relates to a method for producing an aqueous pigment dispersion, an aqueous pigment dispersion, and an aqueous ink for inkjet recording, and more particularly, a method for producing an aqueous pigment dispersion containing an azo pigment having a specific structure, and an aqueous pigment dispersion. And an aqueous ink for inkjet recording.

  Various media have been used as inkjet recording media, and high-quality image quality is required not only for inkjet dedicated paper but also for printing media such as commercially available plain paper, high-quality paper, coated paper, and art paper. . A pigment is preferable as an ink coloring material that gives fastness such as water resistance and light resistance to plain paper and printing media, and various studies have been made on water-based pigment ink including the viewpoint of cost. However, water-based pigment inks generally have the disadvantage that they are easily scattered by light because the pigment is present in the form of dispersed particles, and the resulting image lacks transparency. In addition, the particles tend to aggregate and settle, and are inferior in storage stability and ejection stability compared to dye ink. Various attempts have been made to overcome the problems of such pigment inks.

  For example, Patent Document 1 and Patent Document 2 define the primary particle size distribution width of pigment particles that can contribute to improvements in ink storage stability of pigment inks, clogging of ink heads, and the like. As a method, a method of mixing pigment particles, a surfactant and a pigment insoluble medium is disclosed. According to the method, since the surfactant is adsorbed on the surface of the pigment particles at the time of pigment dispersion, optimal primary particle control is possible in the crystal growth period due to crystallization of the pigment. It is described that a pigment dispersion having a diameter distribution can be obtained.

JP 2003-128955 A JP 2003-113341 A

However, in the methods described in Patent Documents 1 and 2, the improvement of the dispersion state of the pigment is almost dependent only on the surfactant adsorbed on the surface of the pigment particle, so that the crystal growth due to the crystallization of the pigment alone is not possible. In the stage, it is difficult to make all the pigment particles contained in the medium into primary particles. In the obtained pigment dispersion, the water-soluble polymer is adsorbed on the surface of the pigment particles, so that the viscosity of the pigment dispersion composition and the ink made using the pigment increases, or the pigment aggregates. Thus, there is a high possibility that secondary particles having a large particle diameter will be formed. Therefore, the method needs to be further improved with respect to storage stability, solvent resistance and occurrence of clogging at the nozzle opening.
In Patent Documents 1 and 2, the structure of the pigment used in this method is not particularly defined, and it can be interpreted that the method is effective for many commonly used pigments. Such a fact is not recognized even if the examples of Patent Documents 1 and 2 are referred to. Further, since the structure of the pigment is not particularly defined, it is considered that no consideration has been given to the fastness such as solvent resistance and light resistance, which are greatly different depending on the structure of the pigment.

  The present invention has been made paying attention to the above-mentioned problems in water-based pigment dispersions and water-based inks, and its purpose is that the dispersed particle size is small, and all of storage stability, ejection stability, and solvent resistance. It is an object to provide an excellent method for producing an aqueous pigment dispersion, an aqueous pigment dispersion, and an aqueous ink for ink jet.

（一般式（１）中、Ｚは５〜６員ヘテロ環を表し、Ｙ _１ 、Ｙ _２ 、Ｒ _１１ 、Ｒ _１２ は、それぞれ独立に水素原子又は置換基を表し、Ｇ _１ 、Ｇ _２ は、それぞれ独立に水素原子、アルキル基、アラルキル基、アルケニル基、アルキニル基、アリール基又はヘテロ環基を表し、Ｗ _１ 、Ｗ _２ はそれぞれ独立にアルコキシ基、アミノ基、アルキル基又はアリール基を表す。）
＜２＞
前記水不溶性ポリマー（Ｂ）が、アクリル酸及びメタクリル酸の少なくとも一方に由来する構造単位を含むポリマーであり、酸価が４５ｍｇＫＯＨ／ｇ〜１００ｍｇＫＯＨ／ｇであることを特徴とする＜１＞に記載の水系顔料分散体の製造方法。
＜３＞
前記界面活性剤（Ｃ）が、前記顔料溶液中で溶解していることを特徴とする＜１＞又は＜２＞に記載の水系顔料分散体の製造方法。
＜４＞
前記混合工程において、更に、水を混合する工程を含むことを特徴とする＜１＞〜＜３＞のいずれか一項に記載の水系顔料分散体の製造方法。
＜５＞
前記酸溶媒（Ｄ）が、酸又は混合酸と有機溶媒との混合溶媒であり、該有機溶媒の量が該酸溶媒全量に対して３０〜９０質量％であることを特徴とする＜１＞〜＜４＞に記載の水系顔料分散体の製造方法。
＜６＞
前記酸溶媒（Ｄ）が、酸又は混合酸と有機溶媒との混合溶媒であり、前記混合工程において、更に、水を混合する工程を含むことを特徴とする＜１＞に記載の水系顔料分散体の製造方法。
＜７＞
＜１＞〜＜６＞のいずれか一項に記載の製造方法によって製造された水系顔料分散体。
＜８＞
＜７＞に記載の水系顔料分散体を含むインクジェット記録用水性インク。
本発明は、前記＜１＞〜＜８＞に係る発明であるが、以下、それ以外の事項（例えば、下記〔１〕〜〔６〕）についても記載している。
As a result of intensive studies to achieve the above object, the present inventors have determined that a pigment solution in which an azo pigment having a specific structure, a surfactant, a water-insoluble polymer, and an acid solvent are mixed under a certain pH condition. In the above, the above-mentioned problem is obtained by mixing with an aqueous solvent which is compatible with the acid solvent but is a poor solvent for the azo pigment, and depositing fine particles of the azo pigment to obtain a pigment dispersion. The inventors have found that this can be solved, and have completed the present invention.
That is, the said subject can be achieved by the following means.
<1>
(I) a mixing step of mixing a material containing the following A, B, C and D in the following ratio with respect to the total amount of A, B, C and D to obtain a pigment solution;
A: At least one selected from the group consisting of azo pigments represented by the following general formula (1), tautomers, salts and hydrates thereof: 5 to 25% by mass
B: Water-insoluble polymer comprising a hydrophobic structural unit and a hydrophilic structural unit: 1 to 15% by mass
C: Surfactant: 1 to 15% by mass
D: at least one acid solvent selected from the group consisting of acids, mixed acids, and acids or mixed solvents of mixed acids and organic solvents: 50 to 82.6% by mass
(Ii) An aqueous solvent that is compatible with the pigment solution obtained in the mixing step and the acid solvent (D) under the conditions of pH 8 to 13 but is a poor solvent for the azo pigment. And a precipitation / dispersion step of precipitating fine particles of the azo pigment to obtain a pigment dispersion,
A method for producing a water-based pigment dispersion, comprising:
General formula (1):

(In General Formula (1), Z represents a 5-6 membered heterocyclic ring, Y < ₁ >, Y < ₂ > , R < ₁₁ > , R < ₁₂ > represents a hydrogen atom or a substituent each independently, G < ₁ >, G < ₂ > is Each independently represents a hydrogen atom, an alkyl group, an aralkyl group, an alkenyl group, an alkynyl group, an aryl group or a heterocyclic group, and W ₁ and W ₂ each independently represent an alkoxy group, an amino group, an alkyl group or an aryl group. )
<2>
<1>, wherein the water-insoluble polymer (B) is a polymer containing a structural unit derived from at least one of acrylic acid and methacrylic acid, and has an acid value of 45 mgKOH / g to 100 mgKOH / g. A method for producing a water-based pigment dispersion.
<3>
The method for producing an aqueous pigment dispersion according to <1> or <2>, wherein the surfactant (C) is dissolved in the pigment solution.
<4>
The method for producing an aqueous pigment dispersion according to any one of <1> to <3>, wherein the mixing step further includes a step of mixing water.
<5>
<1> characterized in that the acid solvent (D) is an acid or a mixed solvent of a mixed acid and an organic solvent, and the amount of the organic solvent is 30 to 90% by mass with respect to the total amount of the acid solvent. The manufacturing method of the aqueous pigment dispersion as described in <4>.
<6>
The aqueous pigment dispersion as described in <1>, wherein the acid solvent (D) is an acid or a mixed solvent of a mixed acid and an organic solvent, and the mixing step further includes a step of mixing water. Body manufacturing method.
<7>
<1>-<6> The aqueous pigment dispersion manufactured by the manufacturing method as described in any one of.
<8>
<8> A water-based ink for ink-jet recording comprising the water-based pigment dispersion according to <7>.
Although this invention is invention concerning said <1>-<8>, below, other matters (for example, following [1]-[6]) are also described.

（一般式（１）中、Ｚは５〜６員ヘテロ環を表し、Ｙ_１、Ｙ_２、Ｒ_１１、Ｒ_１２は、それぞれ独立に水素原子又は置換基を表し、Ｇ_１、Ｇ_２は、それぞれ独立に水素原子、アルキル基、アラルキル基、アルケニル基、アルキニル基、アリール基又はヘテロ環基を表し、Ｗ_１、Ｗ_２はそれぞれ独立にアルコキシ基、アミノ基、アルキル基又はアリール基を表す。）
〔２〕
前記水不溶性ポリマー（Ｂ）が、アクリル系ポリマー又はメタクリル系ポリマーであり、酸価が４５ｍｇＫＯＨ／ｇ〜１００ｍｇＫＯＨ／ｇであることを特徴とする〔１〕に記載の水系顔料分散体の製造方法。
〔３〕
前記界面活性剤（Ｃ）が、前記顔料溶液中で溶解していることを特徴とする〔１〕又は〔２〕に記載の水系顔料分散体の製造方法。
〔４〕
前記混合工程において、更に、水を混合する工程を含むことを特徴とする〔１〕〜〔３〕のいずれか一項に記載の水系顔料分散体の製造方法。
〔５〕
〔１〕〜〔４〕のいずれか一項に記載の製造方法によって製造された水系顔料分散体。
〔６〕
〔５〕に記載の水系顔料分散体を含むインクジェット記録用水性インク。 [1]
(I) a mixing step of mixing a material containing the following A, B, C and D to obtain a pigment solution;
A: At least one selected from the group consisting of azo pigments represented by the following general formula (1), tautomers thereof, salts and hydrates thereof B: water-insoluble polymer C: surfactant D: A pigment solution obtained in the mixing step under the conditions of at least one acid solvent (ii) pH 8 to 13 selected from the group consisting of an acid, a mixed acid and a mixed solvent of an acid and an organic solvent, and the acid A precipitation / dispersing step in which an aqueous solvent which is compatible with the solvent (D) but is a poor solvent for the azo pigment is mixed to precipitate fine particles of the azo pigment to obtain a pigment dispersion; ,
A method for producing a water-based pigment dispersion, comprising:

(In General Formula (1), Z represents a 5-6 membered heterocyclic ring, Y < ₁ >, Y < ₂ >, R < ₁₁ >, R < ₁₂ > represents a hydrogen atom or a substituent each independently, G < ₁ >, G < ₂ > is Each independently represents a hydrogen atom, an alkyl group, an aralkyl group, an alkenyl group, an alkynyl group, an aryl group or a heterocyclic group, and W ₁ and W ₂ each independently represent an alkoxy group, an amino group, an alkyl group or an aryl group. )
[2]
The method for producing an aqueous pigment dispersion according to [1], wherein the water-insoluble polymer (B) is an acrylic polymer or a methacrylic polymer, and has an acid value of 45 mgKOH / g to 100 mgKOH / g.
[3]
The method for producing an aqueous pigment dispersion according to [1] or [2], wherein the surfactant (C) is dissolved in the pigment solution.
[4]
The method for producing an aqueous pigment dispersion according to any one of [1] to [3], wherein the mixing step further includes a step of mixing water.
[5]
A water-based pigment dispersion produced by the production method according to any one of [1] to [4].
[6]
A water-based ink for ink-jet recording comprising the water-based pigment dispersion described in [5].

According to the present invention, a pigment solution obtained by mixing an azo pigment having a specific structure, a surfactant, a water-insoluble polymer, and an acid solvent has compatibility with the acid solvent under a certain pH condition. However, the azo pigment is mixed with an aqueous solvent which is a poor solvent, and fine particles of the azo pigment are precipitated to obtain a pigment dispersion, whereby the dispersed particle size is small, storage stability, ejection stability, and resistance. A method for producing an aqueous pigment dispersion excellent in all solvent properties, an aqueous pigment dispersion produced by the production method, and an aqueous ink for ink jet can be provided.
The aqueous pigment dispersion of the present invention can be applied to, for example, printing inks such as inkjets, color toners for electrophotography, displays such as LCDs and PDPs, and color filters used in image sensors such as CCDs, paints, and colored plastics. Can be used.

<Method for producing aqueous pigment dispersion>
The method for producing an aqueous pigment dispersion of the present invention comprises a step of obtaining a pigment solution by mixing materials, and precipitation of pigment particles by precipitating pigment fine particles using a specific aqueous solvent in the pigment solution. A dispersion step.

1. Mixing step The mixing step is a step of obtaining a pigment solution by mixing materials containing the following A, B, C and D.
A: At least one selected from the group consisting of azo pigments represented by the following general formula (1), tautomers thereof, salts and hydrates thereof B: water-insoluble polymer C: surfactant D: At least one acid solvent selected from the group consisting of acids, mixed acids, and mixed solvents of acids and organic solvents

(In General Formula (1), Z represents a 5- or 6-membered heterocycle, Y ₁ , Y ₂ , R ₁₁ , and R ₁₂ each independently represent a hydrogen atom or a substituent, and G ₁ and G ₂ are Each independently represents a hydrogen atom, an alkyl group, an aralkyl group, an alkenyl group, an alkynyl group, an aryl group or a heterocyclic group, and W ₁ and W ₂ each independently represent an alkoxy group, an amino group, an alkyl group or an aryl group. .)

The mixing ratio of A, B, C and D is not particularly limited, but A: 5 to 25% by mass, B: 1 to 15% by mass, C: 1 to 15% by mass, D: 50 to 100% by mass It is preferable that A: 8 to 15% by mass, B: 1 to 8% by mass, C: 3 to 10% by mass, and D: 70 to 100% by mass. In addition to A, B, C, and D, the material can contain any component such as an organic solvent and water.
There is no restriction | limiting in particular about the mixing method, The mixing stirring apparatus used normally can be used.

A: The azo pigment represented by the general formula (1), its tautomers, salts and hydrates thereof The azo pigment represented by the general formula (1) has an average primary particle size of 10 to 70 nm. It is preferable and it is more preferable that it is 25-60 nm. By setting it as this range, a favorable volume average particle diameter and polydispersity index (particle size distribution width), for example, the volume average particle diameter (Mv) is 40 to 120 nm, and the polydispersity index (PDI) is 1.0 to A water-based pigment dispersion having a range of 1.6 or the like tends to be easily obtained. The average primary particle size can be controlled by a pigment grinding step or the like by solvent salt milling described later.
In the present invention, the average particle size and the particle size distribution are determined by measuring the volume average particle size by a dynamic light scattering method using a nanotrack particle size distribution measuring device UPA-EX150 (manufactured by Nikkiso Co., Ltd.). Desired.

The compound represented by the general formula (1) easily forms an intramolecular / intermolecular interaction of a dye molecule due to its specific structure, has a low solubility in water or an organic solvent, and has a preferable form of an azo pigment can do.
A pigment is used by being finely dispersed as particles such as a molecular aggregate in a medium, unlike a dye used by being dissolved in water or an organic solvent in a molecular dispersion state.

W ₁ and W ₂ each independently represents an alkoxy group, an amino group, an alkyl group or an aryl group.
The alkoxy group represented by W ₁ or W ₂ is preferably a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, and among them, a substituted or unsubstituted alkoxy group having 1 to 8 carbon atoms, among others. Further, a substituted or unsubstituted alkoxy group having 1 to 4 carbon atoms is preferable. For example, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, i-butoxy group, s- Examples include butoxy group, t-butoxy group, n-octyloxy group, 2-methoxyethoxy group and the like. Particularly preferred is a methoxy group.

Examples of the amino group represented by W ₁ and W ₂ include an alkylamino group, an arylamino group, and a heterocyclic amino group, preferably an amino group, a substituted or unsubstituted alkylamino group having 1 to 30 carbon atoms, Examples thereof include substituted or unsubstituted anilino groups having 6 to 30 carbon atoms, including amino groups, substituted or unsubstituted alkylamino groups having 1 to 8 carbon atoms, and substituted or unsubstituted anilino groups having 6 to 18 carbon atoms. Further, an amino group, a substituted or unsubstituted alkylamino group having 1 to 4 carbon atoms, and a substituted or unsubstituted anilino group having 6 to 12 carbon atoms are preferable. For example, an amino group (—NH ₂ ), methylamino group (-NHCH _3), dimethylamino group _{{-N (CH 3) 2}} , an anilino group (-NHPh), N-methyl - anilino group {-N (CH ) Ph}, diphenylamino group {-N _{(Ph) 2},} and the like. Particularly preferred is an amino group.

Examples of the alkyl group represented by W ₁ and W ₂ include linear, branched, and cyclic substituted or unsubstituted alkyl groups, including cycloalkyl groups, bicycloalkyl groups, and tricyclo structures having many ring structures. To do. An alkyl group (for example, an alkyl group of an alkoxy group or an alkylthio group) in a substituent described below also represents such an alkyl group. Specifically, the alkyl group is preferably an alkyl group having 1 to 30 carbon atoms, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s -Butyl group, t-butyl group, n-octyl group, eicosyl group, 2-chloroethyl group, 2-cyanoethyl group, 2-ethylhexyl group and the like are mentioned, and the cycloalkyl group preferably has 3 to 30 carbon atoms. Substituted or unsubstituted cycloalkyl groups such as cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl group and the like, and the bicycloalkyl group is preferably a substituted or unsubstituted group having 5 to 30 carbon atoms. Bicycloalkyl group, that is, a monovalent group obtained by removing one hydrogen atom from a bicycloalkane having 5 to 30 carbon atoms, for example, bicyclo 1,2,2] heptan-2-yl group, a bicyclo [2,2,2] octan-3-yl group.

The aryl group represented by W ₁ or W ₂ is preferably a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and among them, a substituted or unsubstituted aryl group having 6 to 18 carbon atoms. Further, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms is preferable, and examples thereof include a phenyl group, a p-tolyl group, a naphthyl group, an m-chlorophenyl group, and an o-hexadecanoylaminophenyl group. .

Preferable W ₁ and W ₂ each independently include an alkoxy group, an amino group or an alkyl group, and among them, an alkoxy group or an amino group is preferable, and an alkoxy group having 1 to 5 carbon atoms in total or an amino group (—NH ₂ Group), an alkylamino group having 1 to 5 carbon atoms is more preferable, an alkoxy group having 1 to 3 carbon atoms or an alkylamino group having 1 to 3 carbon atoms is particularly preferable, and among them, a methoxy group is most preferable. When W is an alkoxy group having 1 to 5 carbon atoms, an amino group, or an alkylamino group having 1 to 5 carbon atoms, the dye molecule has strong interaction (hydrogen bonding or π-π stacking) within and between molecules. In terms of good hue and high fastness (light resistance, gas resistance, heat resistance, water resistance, chemical resistance). preferable.

In the general formula (1), R ₁₁ and R ₁₂ each independently represent a hydrogen atom or a substituent. When R ₁₁ and R ₁₂ represent a substituent, the substituent may be a straight chain having 1 to 12 carbon atoms or A branched alkyl group, a linear or branched aralkyl group having 7 to 18 carbon atoms, a linear or branched alkenyl group having 2 to 12 carbon atoms, a linear or branched alkynyl group having 2 to 12 carbon atoms, and 3 carbon atoms -12 linear or branched cycloalkyl group, C3-12 linear or branched cycloalkenyl group (for example, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec- Butyl, t-butyl, 2-ethylhexyl, 2-methylsulfonylethyl, 3-phenoxypropyl, trifluoromethyl, cyclopentyl), halogen atom (for example, chlorine atom, bromine atom), aryl A group (for example, phenyl, 4-t-butylphenyl, 2,4-di-t-amylphenyl), a heterocyclic group (for example, imidazolyl, pyrazolyl, triazolyl, 2-furyl, 2-thienyl, 2-pyrimidinyl, 2 -Benzothiazolyl), cyano group, hydroxyl group, nitro group, carboxy group, amino group, alkyloxy group (for example, methoxy, ethoxy, 2-methoxyethoxy, 2-methylsulfonylethoxy), aryloxy group (for example, phenoxy, 2 -Methylphenoxy, 4-t-butylphenoxy, 3-nitrophenoxy, 3-t-butyloxycarbonylphenoxy, 3-methoxycarbonylphenyloxy, acylamino groups (for example, acetamide, benzamide, 4- (3-t-butyl- 4-hydroxyphenoxy) butane ), Alkylamino groups (for example, methylamino, butylamino, diethylamino, methylbutylamino), arylamino groups (for example, phenylamino, 2-chloroanilino), ureido groups (for example, phenylureido, methylureido, N, N -Dibutylureido), sulfamoylamino group (for example, N, N-dipropylsulfamoylamino), alkylthio group (for example, methylthio, octylthio, 2-phenoxyethylthio), arylthio group (for example, phenylthio, 2-butoxy) -5-t-octylphenylthio, 2-carboxyphenylthio), alkyloxycarbonylamino groups (eg methoxycarbonylamino), alkylsulfonylamino groups and arylsulfonylamino groups (eg methylsulfonylamino) , Phenylsulfonylamino, p-toluenesulfonylamino), carbamoyl group (eg, N-ethylcarbamoyl, N, N-dibutylcarbamoyl), sulfamoyl group (eg, N-ethylsulfamoyl, N, N-dipropylsulfamoyl) , N-phenylsulfamoyl), sulfonyl group (eg, methylsulfonyl, octylsulfonyl, phenylsulfonyl, p-toluenesulfonyl), alkyloxycarbonyl group (eg, methoxycarbonyl, butyloxycarbonyl), heterocyclic oxy group (eg, 1-phenyltetrazol-5-oxy, 2-tetrahydropyranyloxy), azo group (eg, phenylazo, 4-methoxyphenylazo, 4-pivaloylaminophenylazo, 2-hydroxy-4-propanoylsulfate) Nylazo), acyloxy group (for example, acetoxy), carbamoyloxy group (for example, N-methylcarbamoyloxy, N-phenylcarbamoyloxy), silyloxy group (for example, trimethylsilyloxy, dibutylmethylsilyloxy), aryloxycarbonylamino group ( For example, phenoxycarbonylamino), imide group (for example, N-succinimide, N-phthalimide), heterocyclic thio group (for example, 2-benzothiazolylthio, 2,4-di-phenoxy-1,3,5-triazole) -6-thio, 2-pyridylthio), sulfinyl group (for example, 3-phenoxypropylsulfinyl), phosphonyl group (for example, phenoxyphosphonyl, octyloxyphosphonyl, phenylphosphonyl), aryloxycarbonyl group ( Eg to phenoxycarbonyl), an acyl group (e.g., acetyl, 3-phenylpropanoyl, benzoyl), ionic hydrophilic groups (e.g., carboxyl group, a sulfo group, a phosphono group and a quaternary ammonium group).

In the general formula (1), preferred R ₁₁ and R ₁₂ are each independently a substituted or unsubstituted acylamino group having 1 to 8 carbon atoms, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted group. An unsubstituted aryl group having 6 to 18 carbon atoms, or a substituted or unsubstituted heterocyclic group having 4 to 12 carbon atoms, more preferably a linear or branched alkyl group having 1 to 8 carbon atoms in total. Group, a substituted or unsubstituted aryl group having 6 to 18 carbon atoms, among which a linear alkyl group or branched alkyl group having 1 to 8 carbon atoms is preferable, and more specifically, a methyl group or an i-propyl group Alternatively, a t-butyl group is preferable, an i-propyl group or a t-butyl group is particularly preferable, and a t-butyl group is most preferable among them.
By making R ₁₁ and R _{12 a} straight chain alkyl group or a branched alkyl group having a small total carbon number (1 to 4 carbon atoms), the dye molecule arrangement can be sterically controlled (arranged at a certain distance and angle). Become. As a result, a structure having stable intramolecular / intermolecular interaction (hydrogen bond or π-π stacking) is easily formed, and a more stable molecular arrangement structure (for example, a three-dimensional network) can be easily formed. Therefore, it is preferable in terms of good hue, coloring power, and high image fastness (light resistance, gas resistance, heat resistance, water resistance, chemical resistance).

  In the general formula (1), Z represents a 5- or 6-membered heterocyclic group, which may be further condensed. Z is preferably a 5- or 6-membered substituted or unsubstituted heterocyclic group, more preferably a 6-membered nitrogen-containing heterocyclic group, and particularly preferably a 6-membered nitrogen-containing heterocycle having 3 to 10 carbon atoms. It is a cyclic group.

  Examples of the heterocyclic group represented by Z include pyridyl, pyrazinyl, pyridazinyl, pyrimidinyl, triazinyl, quinolinyl, isoquinolinyl, quinazolinyl, cinnolinyl, phthalazinyl, quinoxalinyl, pyrrolyl, indolyl, furyl. , Benzofuryl, thienyl, benzothienyl, pyrazolyl, imidazolyl, benzimidazolyl, triazolyl, oxazolyl, benzoxazolyl, thiazolyl, benzothiazolyl, isothiazolyl, benzisothiazolyl, thiadiazolyl, isoxazolyl, benzisoxazolyl, pyrrolidinyl, piperidinyl, piperidinyl Imidazolidinyl, thiazolinyl, sulfolanyl and the like.

  Examples of preferred heterocyclic groups are pyridyl, pyrimidinyl, S-triazinyl, pyridazinyl, pyrazinyl, 1,2,4-thiadiazolyl, 1,3,4-thiadiazolyl, imidazolyl, more preferably pyridyl, pyrimidinyl, S- Triazinyl, pyridazinyl, and pyrazinyl. Pyrimidinyl and S-triazinyl are particularly preferred from the viewpoint of hue, tinting strength, and image fastness. Furthermore, pyrimidinyl having a substituent at 4,6- and C1-C4 at the 2-position S-triazinyl having an alkoxy group is preferable from the viewpoint of hue and image fastness, and among them, pyrimidinyl having a substituent at 4,6- is most preferable from the viewpoint of improving the light fastness of a good image.

  By making Z a pyrimidinyl group or S-triazinyl group, the bis-type azo dye can easily form an intramolecular hydrogen bond with an amino group and a nitrogen-containing 6-membered heterocycle, and the dye molecule arrangement is controlled sterically (constant It is easy to arrange by distance, angle and flatness. As a result, a structure having stable intramolecular / intermolecular interaction (hydrogen bond or π-π stacking) is easily formed, and a more stable molecular arrangement structure (for example, a three-dimensional network) can be easily formed. Therefore, it is preferable in terms of good hue, coloring power, and high image fastness (light resistance, gas resistance, heat resistance, water resistance, chemical resistance).

G ₁ and G ₂ each independently represents a hydrogen atom, an alkyl group, an aralkyl group, an alkenyl group, an alkynyl group, an aryl group or a heterocyclic group, and particularly preferably a hydrogen atom, a methyl group, an ethyl group, or n- Propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, cyclopropyl group, benzyl group, 2-phenethyl group, vinyl group, allyl group, ethynyl group, propargyl Group, phenyl group, p-tolyl group, naphthyl group, pyridyl group, pyrimidinyl group and pyrazinyl group are preferable, and hydrogen atom, methyl group, phenyl group, pyridyl group, pyrimidinyl group and pyrazinyl group are preferable. 1-8 linear or branched alkyl groups, 2-pyridyl groups, 2,6-pyrimidinyl groups, 2,5-pyrazinyl groups are preferred. Ku, alkyl group having a total carbon number of 1-3 is more preferred. Further, from the viewpoint of hue and image fastness, a hydrogen atom and a methyl group are preferable, and among them, a methyl group is particularly preferable from the viewpoint of improving the hue and light fastness.

Examples of the substituent when Y ₁ and Y ₂ represent a substituent include a halogen atom, an alkyl group, an aralkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, a cyano group, a hydroxyl group, a nitro group, Alkoxy group, aryloxy group, silyloxy group, heterocyclic oxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, amino group, acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, aryl Oxycarbonylamino group, sulfamoylamino group, alkyl or arylsulfonylamino group, mercapto group, alkylthio group, arylthio group, heterocyclic thio group, sulfamoyl group, alkyl or arylsulfinyl group, alkyl or arylsulfo Examples include an alkyl group, an acyl group, an aryloxycarbonyl group, an alkoxycarbonyl group, a carbamoyl group, an aryl or heterocyclic azo group, an imide group, a phosphino group, a phosphinyl group, a phosphinyloxy group, a phosphinylamino group, and a silyl group. As mentioned. Particularly preferable examples of Y include a hydrogen atom, an alkyl group (for example, a methyl group), an aryl group (for example, a phenyl group), a heterocyclic group (for example, a 2-pyridyl group), and an alkylthio group (for example, a methylthio group). Furthermore, they are a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, a phenyl group, and a methylthio group. Further, from the viewpoint of hue and image fastness, a hydrogen atom and a methyl group are preferable, and among them, a hydrogen atom is particularly preferable from the viewpoint of improving hue and light fastness.

In the case where G ₁ , G ₂ , Y ₁ , Y ₂ , W ₁ , W ₂ , R ₁₁ , R ₁₂ , and Z further have a substituent, the following substituent (hereinafter referred to as “substituent J”) May be referred to).

(Substituent J)
For example, halogen atom, alkyl group, aralkyl group, alkenyl group, alkynyl group, aryl group, heterocyclic group, cyano group, hydroxyl group, nitro group, alkoxy group, aryloxy group, silyloxy group, heterocyclic oxy group, acyloxy group , Carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, amino group, acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfamoylamino group, alkyl or arylsulfonylamino group , Mercapto group, alkylthio group, arylthio group, heterocyclic thio group, sulfamoyl group, alkyl or arylsulfinyl group, alkyl or arylsulfonyl group, acyl group, aryloxycarboni Group, an alkoxycarbonyl group, a carbamoyl group, an aryl or heterocyclic azo group, an imido group, a phosphino group, phosphinyl group, phosphinyloxy group, phosphinylamino group, a silyl group.

Each group of the substituent J will be further described.
As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom is mentioned, for example.

  Examples of the alkyl group include linear, branched, and cyclic substituted or unsubstituted alkyl groups, and include cycloalkyl groups, bicycloalkyl groups, and tricyclo structures having many ring structures. An alkyl group (for example, an alkyl group of an alkoxy group or an alkylthio group) in a substituent described below also represents such an alkyl group. Specifically, the alkyl group is preferably an alkyl group having 1 to 30 carbon atoms, such as a methyl group, ethyl group, n-propyl group, isopropyl group, t-butyl group, n-octyl group, eicosyl group, 2-chloroethyl group, 2-cyanoethyl group, 2-ethylhexyl group and the like can be mentioned, and the cycloalkyl group is preferably a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, for example, cyclohexyl group, cyclopentyl group. 4-n-dodecylcyclohexyl group and the like, and the bicycloalkyl group is preferably a substituted or unsubstituted bicycloalkyl group having 5 to 30 carbon atoms, that is, a bicycloalkane having 5 to 30 carbon atoms to a hydrogen atom. A monovalent group such as a bicyclo [1,2,2] heptan-2-yl group, bicycl [2,2,2] octan-3-yl group.

  Examples of the aralkyl group include a substituted or unsubstituted aralkyl group, and the substituted or unsubstituted aralkyl group is preferably an aralkyl group having 7 to 30 carbon atoms. For example, a benzyl group and a 2-phenethyl group can be mentioned.

  Examples of the alkenyl group include linear, branched, and cyclic substituted or unsubstituted alkenyl groups, and include cycloalkenyl groups and bicycloalkenyl groups. Specifically, the alkenyl group is preferably a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, such as a vinyl group, an allyl group, a prenyl group, a geranyl group, an oleyl group, and the like. Is preferably a substituted or unsubstituted cycloalkenyl group having 3 to 30 carbon atoms, that is, a monovalent group obtained by removing one hydrogen atom of a cycloalkene having 3 to 30 carbon atoms, such as 2-cyclopentene-1 -Yl group, 2-cyclohexen-1-yl group and the like, and as the bicycloalkenyl group, a substituted or unsubstituted bicycloalkenyl group, preferably a substituted or unsubstituted bicycloalkenyl group having 5 to 30 carbon atoms, That is, a monovalent group obtained by removing one hydrogen atom of a bicycloalkene having one double bond, for example, bicyclo [2 2,1] hept-2-en-1-yl group, a bicyclo [2,2,2] oct-2-en-4-yl group and the like.

  The alkynyl group is preferably a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms such as an ethynyl group, a propargyl group, and a trimethylsilylethynyl group.

  The aryl group is preferably a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, such as a phenyl group, a p-tolyl group, a naphthyl group, an m-chlorophenyl group, an o-hexadecanoylaminophenyl group, and the like. Can be mentioned.

  The heterocyclic group is preferably a monovalent group obtained by removing one hydrogen atom from a 5- or 6-membered substituted or unsubstituted aromatic or non-aromatic heterocyclic compound, and more preferably a carbon number. Examples thereof include 3 to 30 5- or 6-membered aromatic heterocyclic groups such as a 2-furyl group, a 2-thienyl group, a 2-pyrimidinyl group, and a 2-benzothiazolyl group.

  The alkoxy group is preferably a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, such as a methoxy group, an ethoxy group, an isopropoxy group, a t-butoxy group, an n-octyloxy group, or a 2-methoxyethoxy group. Etc.

  The aryloxy group is preferably a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, such as a phenoxy group, 2-methylphenoxy group, 4-t-butylphenoxy group, 3-nitrophenoxy group, 2 -Tetradecanoylaminophenoxy group etc. are mentioned.

  Preferred examples of the silyloxy group include substituted or unsubstituted silyloxy groups having 0 to 20 carbon atoms such as a trimethylsilyloxy group and a diphenylmethylsilyloxy group.

  Preferred examples of the heterocyclic oxy group include substituted or unsubstituted heterocyclic oxy groups having 2 to 30 carbon atoms, such as a 1-phenyltetrazole-5-oxy group and a 2-tetrahydropyranyloxy group.

  The acyloxy group is preferably a formyloxy group, a substituted or unsubstituted alkylcarbonyloxy group having 2 to 30 carbon atoms, a substituted or unsubstituted arylcarbonyloxy group having 6 to 30 carbon atoms, such as an acetyloxy group, Examples include a pivaloyloxy group, a stearoyloxy group, a benzoyloxy group, and a p-methoxyphenylcarbonyloxy group.

  The carbamoyloxy group is preferably a substituted or unsubstituted carbamoyloxy group having 1 to 30 carbon atoms, such as N, N-dimethylcarbamoyloxy group, N, N-diethylcarbamoyloxy group, morpholinocarbonyloxy group, N , N-di-n-octylaminocarbonyloxy group, Nn-octylcarbamoyloxy group and the like.

  The alkoxycarbonyloxy group is preferably a substituted or unsubstituted alkoxycarbonyloxy group having 2 to 30 carbon atoms, such as a methoxycarbonyloxy group, an ethoxycarbonyloxy group, a t-butoxycarbonyloxy group, or an n-octylcarbonyloxy group. Etc.

  The aryloxycarbonyloxy group is preferably a substituted or unsubstituted aryloxycarbonyloxy group having 7 to 30 carbon atoms, such as phenoxycarbonyloxy group, p-methoxyphenoxycarbonyloxy group, pn-hexadecyloxy. Examples include phenoxycarbonyloxy group.

  The amino group includes an alkylamino group, an arylamino group, and a heterocyclic amino group, preferably an amino group, a substituted or unsubstituted alkylamino group having 1 to 30 carbon atoms, a substituted or unsubstituted group having 6 to 30 carbon atoms. Examples of the substituted anilino group include a methylamino group, a dimethylamino group, an anilino group, an N-methyl-anilino group, and a diphenylamino group.

  The acylamino group is preferably a formylamino group, a substituted or unsubstituted alkylcarbonylamino group having 1 to 30 carbon atoms, a substituted or unsubstituted arylcarbonylamino group having 6 to 30 carbon atoms, such as an acetylamino group, Examples include pivaloylamino group, lauroylamino group, benzoylamino group, 3,4,5-tri-n-octyloxyphenylcarbonylamino group, and the like.

  The aminocarbonylamino group is preferably a substituted or unsubstituted aminocarbonylamino group having 1 to 30 carbon atoms, such as a carbamoylamino group, N, N-dimethylaminocarbonylamino group, or N, N-diethylaminocarbonylamino group. And a morpholinocarbonylamino group.

  The alkoxycarbonylamino group is preferably a substituted or unsubstituted alkoxycarbonylamino group having 2 to 30 carbon atoms, such as methoxycarbonylamino group, ethoxycarbonylamino group, t-butoxycarbonylamino group, n-octadecyloxycarbonylamino. Group, N-methyl-methoxycarbonylamino group and the like.

  The aryloxycarbonylamino group is preferably a substituted or unsubstituted aryloxycarbonylamino group having 7 to 30 carbon atoms, such as phenoxycarbonylamino group, p-chlorophenoxycarbonylamino group, mn-octyloxyphenoxy. Examples thereof include a carbonylamino group.

  The sulfamoylamino group is preferably a substituted or unsubstituted sulfamoylamino group having 0 to 30 carbon atoms, such as a sulfamoylamino group, N, N-dimethylaminosulfonylamino group, Nn- Examples include octylaminosulfonylamino group.

The alkyl or arylsulfonylamino group is preferably a substituted or unsubstituted alkylsulfonylamino group having 1 to 30 carbon atoms, a substituted or unsubstituted arylsulfonylamino group having 6 to 30 carbon atoms, such as a methylsulfonylamino group. Butylsulfonylamino group, phenylsulfonylamino group, 2,3,5-trichlorophenylsulfonylamino group, p-methylphenylsulfonylamino group, and the like.
Preferred examples of the alkylthio group include substituted or unsubstituted alkylthio groups having 1 to 30 carbon atoms, such as a methylthio group, an ethylthio group, and an n-hexadecylthio group.

  Preferred examples of the arylthio group include substituted or unsubstituted arylthio groups having 6 to 30 carbon atoms such as a phenylthio group, a p-chlorophenylthio group, and an m-methoxyphenylthio group.

  Preferred examples of the heterocyclic thio group include substituted or unsubstituted heterocyclic thio groups having 2 to 30 carbon atoms, such as a 2-benzothiazolylthio group and a 1-phenyltetrazol-5-ylthio group.

  The sulfamoyl group is preferably a substituted or unsubstituted sulfamoyl group having 0 to 30 carbon atoms, such as N-ethylsulfamoyl group, N- (3-dodecyloxypropyl) sulfamoyl group, N, N-dimethylsulfuryl group. Examples include a famoyl group, an N-acetylsulfamoyl group, an N-benzoylsulfamoyl group, and an N- (N′-phenylcarbamoyl) sulfamoyl group.

  The alkyl or arylsulfinyl group is preferably a substituted or unsubstituted alkylsulfinyl group having 1 to 30 carbon atoms, a substituted or unsubstituted arylsulfinyl group having 6 to 30 carbon atoms, such as a methylsulfinyl group, an ethylsulfinyl group, phenyl. Examples thereof include a sulfinyl group and a p-methylphenylsulfinyl group.

  The alkyl or arylsulfonyl group is preferably a substituted or unsubstituted alkylsulfonyl group having 1 to 30 carbon atoms, a substituted or unsubstituted arylsulfonyl group having 6 to 30 carbon atoms, such as a methylsulfonyl group, an ethylsulfonyl group, or a phenyl group. A sulfonyl group, p-methylphenylsulfonyl group, etc. are mentioned.

  The acyl group is preferably a formyl group, a substituted or unsubstituted alkylcarbonyl group having 2 to 30 carbon atoms, a substituted or unsubstituted arylcarbonyl group having 7 to 30 carbon atoms, a substituted or unsubstituted group having 2 to 30 carbon atoms. Heterocyclic carbonyl groups bonded to carbonyl groups at substituted carbon atoms, such as acetyl, pivaloyl, 2-chloroacetyl, stearoyl, benzoyl, pn-octyloxyphenylcarbonyl, 2-pyridyl Examples thereof include a carbonyl group and a 2-furylcarbonyl group.

  The aryloxycarbonyl group is preferably a substituted or unsubstituted aryloxycarbonyl group having 7 to 30 carbon atoms, such as phenoxycarbonyl group, o-chlorophenoxycarbonyl group, m-nitrophenoxycarbonyl group, pt- A butylphenoxycarbonyl group etc. are mentioned.

  The alkoxycarbonyl group is preferably a substituted or unsubstituted alkoxycarbonyl group having 2 to 30 carbon atoms, such as a methoxycarbonyl group, an ethoxycarbonyl group, a t-butoxycarbonyl group, and an n-octadecyloxycarbonyl group.

  The carbamoyl group is preferably a substituted or unsubstituted carbamoyl group having 1 to 30 carbon atoms, such as a carbamoyl group, an N-methylcarbamoyl group, an N, N-dimethylcarbamoyl group, or an N, N-di-n-octyl group. Examples thereof include a carbamoyl group and an N- (methylsulfonyl) carbamoyl group.

  The aryl or heterocyclic azo group is preferably a substituted or unsubstituted arylazo group having 6 to 30 carbon atoms, a substituted or unsubstituted heterocyclic azo group having 3 to 30 carbon atoms, such as phenylazo, p-chlorophenylazo, 5-ethylthio-1,3,4-thiadiazol-2-ylazo and the like.

  Preferred examples of the imide group include an N-succinimide group and an N-phthalimide group.

  The phosphino group is preferably a substituted or unsubstituted phosphino group having 0 to 30 carbon atoms, such as a dimethylphosphino group, a diphenylphosphino group, a methylphenoxyphosphino group, and the like.

  The phosphinyl group is preferably a substituted or unsubstituted phosphinyl group having 0 to 30 carbon atoms, such as a phosphinyl group, a dioctyloxyphosphinyl group, a diethoxyphosphinyl group, and the like.

  Preferred examples of the phosphinyloxy group include substituted or unsubstituted phosphinyloxy groups having 0 to 30 carbon atoms such as a diphenoxyphosphinyloxy group and a dioctyloxyphosphinyloxy group.

  The phosphinylamino group is preferably a substituted or unsubstituted phosphinylamino group having 0 to 30 carbon atoms, such as a dimethoxyphosphinylamino group or a dimethylaminophosphinylamino group.

  Preferred examples of the silyl group include substituted or unsubstituted silyl groups having 0 to 30 carbon atoms such as a trimethylsilyl group, a t-butyldimethylsilyl group, and a phenyldimethylsilyl group.

  Among the above substituents, those having a hydrogen atom may be substituted with the above substituent. Examples of such a substituent include an alkylcarbonylaminosulfonyl group, an arylcarbonylaminosulfonyl group, an alkylsulfonylaminocarbonyl group, and an arylsulfonylaminocarbonyl group. Examples thereof include a methylsulfonylaminocarbonyl group, a p-methylphenylsulfonylaminocarbonyl group, an acetylaminosulfonyl group, and a benzoylaminosulfonyl group.

  In addition, about the preferable combination of a substituent of the compound represented by the said General formula (1), the compound whose at least 1 of a various substituent is the said preferable group is preferable, and many more various substituents are the said preferable. More preferred are compounds that are groups, and most preferred are compounds in which all substituents are the preferred groups.

  A particularly preferable combination as the azo pigment represented by the general formula (1) of the present invention includes the following (A) to (E).

(A) W ₁ and W ₂ are each independently an alkoxy group (eg, methoxy group, ethoxy group, i-propoxy group, t-butoxy group), amino group (eg, —NH ₂ group, methylamino group, dimethyl group). Amino group, anilino group), alkyl group (for example, methyl group, ethyl group, n-propyl group, i-propyl group, t-butyl group, cyclopropyl group) or aryl group (for example, phenyl group, p-tolyl group) , A naphthyl group), among which an alkoxy group, an amino group or an alkyl group is preferable, an alkoxy group or an amino group is more preferable, and an alkoxy group having 1 to 5 carbon atoms or an amino group (-NH ₂ group) is more preferable. ) is the total alkylamino group having a carbon number of 1 to 5, particularly preferably, the total alkoxy group having a carbon number of 1-3, an amino group (-NH ₂ group), a total number of carbon atoms from 1 to 3 Alkylamino group, further, a methoxy group (-OCH ₃ group), an ethoxy group _(-OC 2 _{H 5} group), amino group (-NH ₂ group) are preferable, among which a methoxy group (-OCH ₃ group) is Most preferred.

(B) R ₁₁ and R ₁₂ are each independently a hydrogen atom or a substituent (for example, a substituted or unsubstituted acylamino group having 1 to 8 carbon atoms, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms). Group, a substituted or unsubstituted aryl group having 6 to 18 carbon atoms in total, or a substituted or unsubstituted heterocyclic group having 4 to 12 carbon atoms in total, and more preferably a straight chain having 1 to 8 carbon atoms in total. It is an alkyl group or a branched alkyl group, more preferably a methyl group, an i-propyl group or a tert-butyl group, particularly preferably an i-propyl group or a t-butyl group, and most preferably a t-butyl group.

(C) Z represents a divalent 5- to 6-membered heterocyclic group, which may be further condensed. Z is preferably a 5- or 6-membered substituted or unsubstituted nitrogen-containing heterocycle, and more preferably a 6-membered substituted or unsubstituted nitrogen-containing heterocycle. For example, pyrrole ring, pyrazole ring, triazole ring, imidazole ring, thiazole ring, isothiazole ring, oxazole ring, isoxazole ring, thiadiazole ring, thiophene ring, furan ring, pyridine ring, pyrimidine ring, triazine ring, pyridazine ring, pyrazine A ring is preferred, and particularly preferred is a 6-membered nitrogen-containing heterocyclic ring, specifically a 6-membered nitrogen-containing heterocyclic group having 3 to 10 carbon atoms. Further preferred examples of the heterocyclic ring are a pyridine ring, a pyrimidine ring, an S-triazine ring, a pyridazine ring and a pyrazine ring, and more preferably a pyridine ring, a pyrimidine ring, an S-triazine ring, a pyridazine ring and a pyrazine ring. More preferred are a pyrimidine ring and an S-triazine ring, particularly a pyrimidine ring and an S-triazine ring. Further, a pyrimidine ring having a substituent at 4,6- and an alkoxy group having 1 to 4 carbon atoms at the 2-position. S-triazine ring is preferable, and among them, a pyrimidine ring having a substituent at 4,6- is most preferable.

(D) G ₁ and G ₂ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aralkyl group, an alkenyl group, an alkynyl group, an aryl group or a heterocyclic group, and particularly preferably a hydrogen atom or a methyl group. , Ethyl group, n-propyl group, isopropyl group, t-butyl group, cyclopropyl group, benzyl group, 2-phenethyl group, vinyl group, allyl group, ethynyl group, propargyl group, phenyl group, p-tolyl group, naphthyl Group, pyridyl group, pyrimidinyl group and pyrazinyl group are preferable, and hydrogen atom, methyl group, phenyl group, pyridyl group, pyrimidinyl group and pyrazinyl group are preferable, and among them, methyl group, 2-pyridyl group and 2,6-pyrimidinyl group are preferable. 2,5-pyrazinyl group is preferred, and methyl group is most preferred.

(E) Y ₁ and Y ₂ are each independently a hydrogen atom, an alkyl group (for example, a methyl group), an aryl group (for example, a phenyl group), a heterocyclic group (for example, a 2-pyridyl group), an alkylthio group (for example, a methylthio group) A hydrogen atom, a methyl group, a phenyl group, and a methylthio group, and among them, a hydrogen atom is most preferable.

The present invention includes within its scope tautomers of the azo pigments represented by the general formula (1).
The general formula (1) is shown in the form of an extreme structural formula among several tautomers that can be taken in terms of chemical structure, but may be a tautomer other than the structure described, You may use as a mixture containing these tautomers.
For example, the pigment represented by the general formula (1) may be an azo-hydrazone tautomer represented by the following general formula (1 ′). The present invention includes in its scope a compound represented by the following general formula (1 ′), which is a tautomer of the azo pigment represented by the general formula (1).

(In General Formula (1 ′), R ₁₁ , R ₁₂ , W ₁ , W ₂ , Y ₁ , Y ₂ , G ₁ , G ₂ and Z are R ₁₁ , R ₁₂ , W _{1 in} General Formula (1). , W ₂ , Y ₁ , Y ₂ , G ₁ , G ₂ and Z.

  Among the azo pigments represented by the general formula (1) of the present invention, an azo pigment represented by the following general formula (2) is preferable.

G ₁ , G ₂ , R ₁₁ , R ₁₂ , W ₁ , W ₂ , Y ₁ and Y ₂ in the general formula (2) are the same as G ₁ , G ₂ , R ₁₁ , _{R 12, W 1, W 2} , the same meaning as _{Y 1} and _{Y 2.}
Het. Represents a heterocycle formed by Z in the general formula (1), and X ₁₁ and X ₁₂ are each independently Het. Each represents a heteroatom in the heterocycle of which

  In the present invention, the azo pigment represented by the general formula (1) preferably has a substituent that forms an intramolecular hydrogen bond or an intramolecular cross-hydrogen bond. It preferably has at least one substituent that forms an intramolecular cross-hydrogen bond, more preferably includes at least three substituents that form an intramolecular hydrogen bond, and further includes at least three or more substituents. It is particularly preferred that each has a substituent that forms an intramolecular hydrogen bond, and at least two of these hydrogen bonds have a substituent that forms an intramolecular cross-hydrogen bond.

  Among the azo pigments represented by the general formula (1), examples of the particularly preferred azo pigments represented by the general formula (1) include azo pigments represented by the above general formula (2).

The reason why this structure is preferable is that, as shown in the general formula (2), a nitrogen atom, a hydrogen atom, and a heteroatom (a hydrazone group that is an azo group or a tautomer thereof) constituting a heterocycle contained in the azo pigment structure. The nitrogen atom and the oxygen atom of the carbonyl group or the nitrogen atom of the amino group) can easily form at least one intramolecular hydrogen bond (intramolecular hydrogen bond).
More preferably, as shown in the general formula (2), a nitrogen atom, a hydrogen atom of an amino group and a hetero atom (an hydrazone group which is an azo group or a tautomer thereof) constituting a heterocyclic group contained in an azo pigment structure Of the carbonyl group and the oxygen atom of the carbonyl group or the nitrogen atom of the amino group) easily form at least four intramolecular hydrogen bonds, and easily form at least two intramolecular hydrogen bonds. It is easy to do.
As a result, the planarity of the molecule is improved, and the intramolecular / intermolecular interaction (hydrogen bond / π-π stacking) is improved, and for example, the crystallinity of the azo pigment represented by the general formula (2) is increased ( It is most preferable because it can easily form a higher order structure, and the required performance as a pigment is greatly improved in light fastness, heat stability, wet heat stability, water resistance, gas resistance and / or solvent resistance. An example.

  Moreover, in this invention, even if it contains isotopes (for example, 2H, 3H, 13C, 15N) in the compound represented by General formula (1)-(2), it is applicable.

  In the present invention, from the viewpoint of effects, azo pigments represented by the following general formula (10) among the azo pigments represented by the general formulas (1) to (2) are more preferable, and represented by the general formula (11). Particularly preferred are azo pigments.

(In General Formula (10), Z represents a 5- or 6-membered nitrogen-containing heterocycle, and W ₁ and W ₂ each independently represent an alkoxy group, an amino group, an alkyl group, or an aryl group.)

(In general formula (11), Z ′ represents a 6-membered nitrogen-containing heterocycle.)
In the general formula (11), examples of the 6-membered nitrogen-containing heterocycle represented by Z ′ include the same as the 6-membered nitrogen-containing heterocycle represented by Z in the general formula (1), and preferred examples thereof are also the same. .

  Specific examples of the azo pigments represented by the general formulas (1) to (2) are shown below, but the azo pigments used in the present invention are not limited to the following examples. The structures of the following specific examples are shown in the form of an ultimate structural formula among several tautomers that can be taken in terms of chemical structure, but have tautomeric structures other than those described. It goes without saying that it is also good.

Among the above, Pig. From the point of the effect of the present invention. -1, Pig. -18, Pig. -25 is preferred.
In the present invention, even if a tautomer exists depending on the structure of the compound, it is described in one of the representative forms in the present invention. Azo pigments. Further, salts and hydrates of the azo pigments of the present invention are also included in the azo pigments of the present invention.

  The pigment represented by the general formula (1) of the present invention may have any chemical form as long as the chemical structural formula is the general formula (1) or a tautomer thereof, and may be any crystalline form called polymorph.

Crystal polymorphs refer to the same chemical composition but different arrangement of building blocks (molecules or ions) in the crystal. The crystal structure determines the chemical and physical properties, and each polymorph can be distinguished by its rheology, color, and other color characteristics. Different polymorphs can also be confirmed by X-Ray Diffraction (powder X-ray diffraction measurement result) or X-Ray Analysis (X-ray crystal structure analysis result).
When the crystalline polymorph exists in the pigment represented by the general formulas (1) to (2) of the present invention, it may be any polymorph, or may be a mixture of two or more polymorphs. The main component is preferably a single crystal type. That is, it is preferable that the crystalline polymorph is not mixed, and the content of the azo pigment having a single crystal type is 70% to 100%, preferably 80% to 100%, more preferably 90% with respect to the entire azo pigment. -100%, more preferably 95% -100, particularly preferably 100%. By using an azo pigment having a single crystal form as a main component, the regularity of the dye molecule arrangement is improved, the intramolecular / intermolecular interaction is strengthened, and a higher-order three-dimensional network is easily formed. . As a result, it is preferable in terms of performance required for pigments such as improvement of hue, light fastness, heat fastness, humidity fastness, oxidizing gas fastness and solvent resistance.
The mixing ratio of crystal polymorphs in azo pigments is based on solid physicochemical measurements such as single crystal X-ray crystal structure analysis, powder X-ray diffraction (XRD), crystal micrograph (TEM), IR (KBr method), etc. I can confirm.

  In the present invention, when the azo pigment represented by the general formula (1) has an acid group, a part or all of the acid group may be in a salt form. Type pigments may be mixed. Examples of the salt types include alkali metal salts such as Na, Li and K, alkaline earth metal salts such as Mg, Ca and Ba, ammonium salts which may be substituted with alkyl groups or hydroxyalkyl groups, Or the salt of an organic amine is mentioned. Examples of organic amines include lower alkyl amines, hydroxy-substituted lower alkyl amines, carboxy-substituted lower alkyl amines, and polyamines having 2 to 10 alkyleneimine units having 2 to 4 carbon atoms. In the case of these salt types, the type is not limited to one type, and a plurality of types may be mixed.

  Further, in the structure of the pigment used in the present invention, when a plurality of acid groups are contained in one molecule, the plurality of acid groups may be salt type or acid type and may be different from each other.

  In the present invention, the azo pigment represented by the general formula (1) may be a hydrate containing water molecules in the crystal.

  Next, an example of a method for producing the azo pigment represented by the general formula (1) will be described. For example, the heterocyclic amine represented by the following general formula (A) is diazonium under acidic conditions, subjected to a coupling reaction with a compound represented by the following general formula (B), followed by post-treatment by a conventional method, An azo pigment represented by the formula (1) can be produced.

(In the general formulas (A) and (B), G, Y, W, R ₁₁ , R ₁₂ , Z are the corresponding G ₁ , G ₂ , Y ₁ , Y ₂ , W ₁ , in the general formula (1), W ₂ , R ₁₁ , R ₁₂ and Z are synonymous.)

The heterocyclic amines represented by the above general formula (A) are generally known and commonly used methods such as those described in Helv. Chim. Acta, 41, 1958, 1052 to 1056 and Helv. Chim. Acta, 42, 1959, 349 to 352, etc., and a method analogous thereto.
The compound represented by the general formula (B) can be produced by the method described in International Publication No. 06/082669 and JP-A-2006-57076 and a method according thereto.
The diazoniumation reaction of the heterocyclic amine represented by the general formula (A) is, for example, in an acidic solvent such as sulfuric acid, phosphoric acid, acetic acid, hydrochloric acid, methanesulfonic acid, sodium nitrite, nitrosyl sulfuric acid, isoamyl nitrite, etc. This reagent can be reacted at a temperature of 15 ° C. or lower for about 10 minutes to 6 hours.
The coupling reaction is performed by reacting the diazonium salt obtained by the above-described method with the compound represented by the general formula (B) at 40 ° C. or lower, preferably at 25 ° C. or lower for about 10 minutes to 12 hours. be able to.
In some cases, crystals are precipitated in this way, but in general, water or an alcohol solvent is added to the reaction solution to precipitate the crystals, and the crystals can be collected by filtration. it can. In addition, an alcohol solvent, water or the like can be added to the reaction solution to precipitate crystals, and the precipitated crystals can be collected by filtration. The crystals collected by filtration can be washed and dried as necessary to obtain an azo pigment represented by the general formula (1).

  Although the compound represented by the general formula (1) is obtained as a crude azo pigment (crude) by the above production method, when used as a pigment in the present invention, a post-treatment may be performed before being subjected to the mixing step. desirable. This is to control the primary particle size. Examples of post-treatment methods include solvent salt milling, salt milling, dry milling, solvent milling, pigment particle control step by grinding treatment such as acid pasting, solvent heating treatment, resin, surfactant and dispersant. The surface treatment process by etc. is mentioned.

When the primary particle diameter of the compound represented by the general formula (1) is set to 10 to 70 nm by post-treatment, it is preferable to perform solvent heat treatment and / or solvent salt milling, and solvent salt milling may be performed. More preferred.
Examples of the solvent used in the solvent heat treatment include water, aromatic hydrocarbon solvents such as toluene and xylene, halogenated hydrocarbon solvents such as chlorobenzene and o-dichlorobenzene, and alcohols such as isopropanol and isobutanol. Examples thereof include solvents, polar aprotic organic solvents such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, glacial acetic acid, pyridine, and mixtures thereof. An inorganic or organic acid or base may be further added to the solvents mentioned above. Although the temperature of the solvent heat treatment varies depending on the desired primary particle size of the pigment, in the present invention, it is preferably 40 to 150 ° C, more preferably 60 to 100 ° C. The treatment time is preferably 30 minutes to 24 hours.

Solvent salt milling is, for example, at least one selected from the group consisting of azo pigments, tautomers thereof, salts and hydrates thereof (hereinafter sometimes referred to as “azo pigments”), and water-soluble. This is a grinding process in which a mixture containing an inorganic salt and a water-soluble organic solvent is charged into a kneader and kneaded therein.
As the water-soluble inorganic salt, a commonly used water-soluble inorganic salt can be used without particular limitation. Specifically, it is preferable to use inorganic salts such as sodium chloride, potassium chloride, sodium sulfate, and potassium sulfate. Moreover, 0.5-50 micrometers is preferable, as for the average particle diameter of the water-soluble inorganic salt to be used, 1-20 micrometers is more preferable, and 1-10 micrometers is still more preferable. The amount of the inorganic salt used can be 1 to 30 times by mass with respect to the azo pigment and the like, and preferably 3 to 20 times by mass and 5 to 15 times by mass from the viewpoint of productivity. More preferred.
The water-soluble organic solvent is preferably a solvent that dissolves in water and does not substantially dissolve the azo pigment and the water-soluble inorganic salt. Since the solvent easily evaporates due to a temperature rise during kneading, From the viewpoint, a high boiling point solvent is preferable. The water-soluble organic solvent can be used to adjust the mixture containing the crude azo pigment and the water-soluble inorganic salt to a hardness applicable to kneading. Examples of such water-soluble organic solvents include diethylene glycol, glycerin, ethylene glycol, propylene glycol, liquid polyethylene glycol, liquid polypropylene glycol, 2- (methoxymethoxy) ethanol, 2-butoxyethanol, 2- (isopentyloxy). Ethanol, 2- (hexyloxy) ethanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, 1-methoxy-2-propanol, 1-ethoxy-2-propanol , Dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, di B propylene glycol or mixtures thereof. The amount of the water-soluble organic solvent used is preferably 0.1 to 5 times by mass with respect to the azo pigment or the like. The kneading temperature is preferably 20 to 130 ° C, particularly preferably 40 to 110 ° C. As a kneader, for example, a kneader or a mix muller can be used.

B: Surfactant As the surfactant in the present invention, nonionic, cationic, anionic, betaine surfactants and the like that are usually used in the technical field can be exemplified, but they are prepared in the mixing step. It can be dissolved in the pigment solution. The surfactant is preferably a low molecular surfactant. This is because the surfactant is sufficiently dissolved in the pigment solution, and the surfactant is a low-molecular surfactant having high fluidity, whereby the pigment dispersion effect of the surfactant can be sufficiently obtained.
As the low molecular surfactant in the present invention, a compound having a structure having both a hydrophilic part and a hydrophobic part in the molecule can be used effectively, and an anionic surfactant, a cationic surfactant, an amphoteric interface, etc. Either an activator or a nonionic surfactant can be used.
The molecular weight of the low molecular surfactant is preferably 100 to 10,000, and more preferably 150 to 4000.

Specific examples of anionic surfactants include sodium dodecylbenzenesulfonate, sodium lauryl sulfate, sodium alkyldiphenyl ether disulfonate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate, sodium stearate, potassium oleate, sodium dioctyl. Sulfosuccinate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, sodium dialkylsulfosuccinate, sodium stearate, sodium oleate, t-octylphenoxyethoxypolyethoxyethyl Examples include sodium sulfate, etc., and select one or more of these Rukoto can.
Specific examples of the nonionic surfactant include, for example, polyoxyethylene lauryl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene oleyl phenyl ether, polyoxyethylene nonyl phenyl ether, oxyethylene / oxypropylene block copolymer, t- Examples include octylphenoxyethyl polyethoxyethanol, nonylphenoxyethyl polyethoxyethanol, and the like, and one or more of these can be selected.
Examples of the cationic surfactant include tetraalkylammonium salts, alkylamine salts, benzalkonium salts, alkylpyridium salts, imidazolium salts, and the like. Specific examples thereof include dihydroxyethyl stearylamine and 2-heptadecenyl. -Hydroxyethyl imidazoline, lauryl dimethyl benzyl ammonium chloride, cetyl pyridinium chloride, stearamide methyl pyridium chloride and the like.

C: Water-insoluble polymer The water-insoluble polymer in the present invention is not particularly limited as long as it is a resin that dissolves in an organic solvent and covers at least a part of the azo pigment represented by the general formula (1) and can be dispersed in a dispersion medium. There is no. Examples thereof include nonionic polymer compounds, anionic polymer compounds, cationic polymer compounds, and amphoteric polymer compounds, which are copolymers of monomers having an ethylenically unsaturated group.

  The water-insoluble polymer in the present invention can exist stably in the dispersion medium, and from the viewpoint of facilitating the adhesion or deposition of aggregates and facilitating the removal of the adhered aggregates, the hydrophobic structural unit and the hydrophilic It is preferable that the resin is composed of a structural unit.

  Examples of the hydrophobic structural unit include vinyls such as (meth) acrylates, (meth) acrylamides, styrenes, and vinyl esters that do not belong to the hydrophilic structural unit (for example, have no hydrophilic functional group). Mention may be made of structural units derived from monomers and the like, as well as hydrophobic structural units having an aromatic ring via a linking group at the atoms forming the main chain. These structural units can be used individually by 1 type or in mixture of 2 or more types.

Examples of the (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, and the like. ) Acrylate, ethyl (meth) acrylate, and butyl (meth) acrylate are preferable, and methyl (meth) acrylate and ethyl (meth) acrylate are particularly preferable.
Examples of the (meth) acrylamides include N-cyclohexyl (meth) acrylamide, N- (2-methoxyethyl) (meth) acrylamide, N, N-diallyl (meth) acrylamide, N-allyl (meth) acrylamide, and the like. (Meth) acrylamides.
Examples of the styrenes include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, isopropyl styrene, n-butyl styrene, tert-butyl styrene, methoxy styrene, butoxy styrene, acetoxy styrene, chlorostyrene, dichlorostyrene, Examples thereof include bromostyrene, chloromethylstyrene, hydroxystyrene protected with a group that can be deprotected by an acidic substance (for example, t-Boc), methyl vinylbenzoate, α-methylstyrene, vinylnaphthalene, and the like. Styrene and α-methylstyrene are preferred.
Examples of the vinyl esters include vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl propionate, vinyl butyrate, vinyl methoxyacetate, and vinyl benzoate. Of these, vinyl acetate is preferable.

  In the “hydrophobic structural unit having an aromatic ring via a linking group on an atom constituting the main chain”, the aromatic ring is bonded to the atom constituting the main chain of the water-insoluble polymer via the linking group. Since a suitable distance is maintained between the hydrophobic aromatic ring and the hydrophilic structural unit, the interaction between the water-insoluble polymer and the pigment is likely to occur. Adsorbs firmly and dispersibility is further improved.

The hydrophilic structural unit is not particularly limited as long as it is a structural unit derived from a monomer containing a hydrophilic group. The hydrophilic group may be any of anionic, cationic and nonionic. In the present invention, from the viewpoint of dispersibility, the hydrophilic structural unit preferably includes at least one structural unit containing an anionic hydrophilic group, and includes a structural unit derived from at least one of acrylic acid and methacrylic acid. It is preferable.
In the present invention, the hydrophilic structural unit can be used alone or in combination of two or more.

  The water-insoluble polymer in the present invention is preferably an acrylic polymer or a methacrylic polymer containing a structural unit derived from at least one of acrylic acid and methacrylic acid, but may contain other hydrophilic structural units. Examples of other hydrophilic structural units include structural units derived from monomers having a nonionic hydrophilic group or a cationic hydrophilic group.

Thus, when the water-insoluble polymer in the present invention has an anionic group, the acid value of the water-insoluble polymer is preferably from 30 mgKOH / g to 100 mgKOH / g from the viewpoint of pigment dispersibility and storage stability. 30 mgKOH / g or more and 85 mgKOH / g or less is more preferable, and 50 mgKOH / g or more and 85 mgKOH / g or less is particularly preferable.
The acid value is defined as the mass (mg) of KOH required to completely neutralize the anionic group in 1 g of the water-insoluble polymer, and is measured by the method described in JIS standards (JIS K0070, 1992). Is.

  Examples of the nonionic or cationic “hydrophilic functional group” include a hydroxyl group, an amino group, an amide group (with a nitrogen atom unsubstituted), and alkylene oxides such as polyethylene oxide and polypropylene oxide described later.

  Examples of the monomer having a nonionic or cationic hydrophilic group include (meth) acrylates, (meth) acrylamides, and vinyl esters having a nonionic or cationic hydrophilic functional group. Mention may be made of structural units derived from vinyl monomers.

  Monomers that form hydrophilic structural units having nonionic or cationic hydrophilic groups include functional groups capable of forming polymers such as ethylenically unsaturated bonds and nonionic or cationic hydrophilic functions. If it has a group, there will be no restriction | limiting in particular, It can select from a well-known monomer. Specific examples include hydroxyethyl (meth) acrylate, hydroxybutyl (meth) acrylate, (meth) acrylamide, aminoethyl acrylate, aminopropyl acrylate, and (meth) acrylate containing an alkylene oxide polymer. Can do.

  The hydrophilic structural unit having a nonionic or cationic hydrophilic group can be formed by polymerization of a corresponding monomer, but a hydrophilic functional group may be introduced into the polymer chain after polymerization.

  The hydrophilic structural unit having a nonionic hydrophilic group is more preferably a hydrophilic structural unit having an alkylene oxide structure. The alkylene moiety of the alkylene oxide structure is preferably an alkylene moiety having 1 to 6 carbon atoms, more preferably an alkylene moiety having 2 to 6 carbon atoms, and particularly preferably an alkylene moiety having 2 to 4 carbon atoms from the viewpoint of hydrophilicity. Moreover, as a polymerization degree of an alkylene oxide structure, 1-120 are preferable, 1-60 are more preferable, and 1-30 are especially preferable.

  Moreover, it is also a preferable aspect that the hydrophilic structural unit having a nonionic hydrophilic group is a hydrophilic structural unit containing a hydroxyl group. The number of hydroxyl groups in the structural unit is not particularly limited, and is preferably 1 to 4, more preferably 1 to 3, from the viewpoint of hydrophilicity of the water-insoluble polymer and compatibility with the solvent and other monomers during polymerization. 1-2 is particularly preferred.

As the water-insoluble polymer in the present invention, the composition of the hydrophilic structural unit and the hydrophobic structural unit affects the degree of hydrophilicity and hydrophobicity of each, but the ratio of the hydrophilic structural unit is 15% by mass or less. It is preferable. At this time, it is preferable that a hydrophobic structural unit is a ratio exceeding 80 mass% with respect to the whole mass of a water-insoluble polymer, and it is more preferable that it is 85 mass% or more.
When the content of the hydrophilic structural unit is 15% by mass or less, the amount of the component dissolved alone in the aqueous medium is suppressed, and various properties such as pigment dispersion are improved. Is obtained.

  A preferred content ratio of the hydrophilic structural unit is in the range of more than 0% by mass and 15% by mass or less, more preferably in the range of 2 to 15% by mass, and still more preferably, with respect to the total mass of the water-insoluble polymer. It is in the range of 5 to 15% by mass, particularly preferably in the range of 8 to 12% by mass.

  The content of the aromatic ring group contained in the water-insoluble polymer is preferably 27% by mass or less, more preferably 25% by mass or less, and more preferably 20% by mass or less, based on the total mass of the water-insoluble polymer. More preferably. Especially, it is preferable that it is 15-20 mass%, and the range of 17-20 mass% is more preferable. When the content ratio of the aromatic ring is within the above range, the scratch resistance is improved.

The molecular weight of the water-insoluble polymer in the present invention is preferably 30,000 or more in terms of mass average molecular weight (Mw), more preferably 30,000 to 150,000, still more preferably 30,000 to 100,000, particularly preferably 30,000 to 80,000. When the molecular weight is 30,000 or more, the steric repulsion effect as a dispersant tends to be good, and the steric effect makes it easy to adsorb to the pigment.
Further, the number average molecular weight (Mn) is preferably in the range of 1,000 to 100,000, particularly preferably in the range of 3,000 to 50,000. When the number average molecular weight is within the above range, a function as a coating film in the pigment or a function as a coating film of the ink composition can be exhibited. The water-insoluble polymer in the present invention is preferably used in the form of an alkali metal or organic amine salt.

  The molecular weight distribution (mass average molecular weight / number average molecular weight) of the water-insoluble polymer in the present invention is preferably in the range of 1 to 6, and more preferably in the range of 1 to 4. When the molecular weight distribution is within the above range, the dispersion stability and ejection stability of the ink can be improved.

  The number average molecular weight and the mass average molecular weight are measured by gel permeation chromatography (GPC). GPC uses HLC-8020GPC (manufactured by Tosoh Corporation), and uses three columns, TSKgel SuperHZM-H, TSKgel SuperHZ4000, and TSKgel SuperHZ200 (both manufactured by Tosoh Corporation, 4.6 mm ID × 15 cm). The molecular weight is obtained by converting THF (tetrahydrofuran) as a liquid and polystyrene as a standard substance. The conditions are a sample concentration of 0.35 mass%, a flow rate of 0.35 ml / min, a sample injection amount of 10 μl, a measurement temperature of 40 ° C., and an IR detector. In addition, the calibration curve is “standard sample TSK standard, polystyrene” manufactured by Tosoh Corporation: “F-40”, “F-20”, “F-4”, “F-1”, “A-5000”, It is prepared from 8 samples of “A-2500”, “A-1000”, “n-propylbenzene”.

The water-insoluble polymer in the present invention can be synthesized by various polymerization methods such as solution polymerization, precipitation polymerization, suspension polymerization, precipitation polymerization, bulk polymerization, and emulsion polymerization. The polymerization reaction can be performed by a known operation such as a batch system, a semi-continuous system, or a continuous system. The polymerization initiation method includes a method using a radical initiator, a method of irradiating light or radiation, and the like. These polymerization methods and polymerization initiation methods are described in, for example, the revised version of Tsuruta Junji “Polymer Synthesis Method” (published by Nikkan Kogyo Shimbun, 1971), Takatsu Otsu, Masaaki Kinoshita, “Experimental Methods for Polymer Synthesis” , Published in 1972, pages 124-154.
Among the polymerization methods, a solution polymerization method using a radical initiator is particularly preferable. As the solvent used in the solution polymerization method, a commonly used solvent can be used without particular limitation. A solvent may be used individually by 1 type or in combination of 2 or more types. Moreover, you may use as a mixed solvent with water. The polymerization temperature needs to be set in relation to the molecular weight of the polymer to be produced, the type of initiator, etc., and is usually about 0 ° C. to 100 ° C., but the polymerization is preferably performed in the range of 50 to 100 ° C. . Although reaction pressure can be selected suitably, it is 1-100 kg / cm < ² > normally, and about 1-30 kg / cm < ² > is especially preferable. The reaction time is about 5 to 30 hours. The obtained resin may be subjected to purification such as reprecipitation.

D: Acid, mixed acid and mixed solvent of acid and organic solvent (acid solvent)
The acid used in the mixing step means an acid that can be dissolved even if it does not completely dissolve the azo compound, and is preferably an acid that completely dissolves the azo compound. As the acid, an inorganic acid (also called a mineral acid) and an organic acid can be used. Examples of the inorganic acid include hydrochloric acid, phosphoric acid, and sulfuric acid, preferably phosphoric acid and sulfuric acid, and more preferably sulfuric acid. . Examples of the organic acid include formic acid, acetic acid, propionic acid, trifluoroacetic acid, oxalic acid, methanesulfonic acid, and trifluoromethanesulfonic acid, preferably acetic acid, propionic acid, and methanesulfonic acid, and more preferably acetic acid. Methanesulfonic acid. These acids may be used alone or in combination.

  Examples of the mixed acid include phosphoric acid / acetic acid, sulfuric acid / acetic acid, methanesulfonic acid / acetic acid, acetic acid / propionic acid, and preferably sulfuric acid / acetic acid, sulfuric acid / propionic acid, sulfuric acid / acetic acid / propionic acid, methanesulfone. Acid / acetic acid, more preferably sulfuric acid / acetic acid, sulfuric acid / acetic acid / propionic acid, and sulfuric acid / acetic acid is particularly preferable. 1 / (0.1-20) is preferable, as for the mass ratio of these mixed acids, 1 / (0.5-10) is more preferable, More preferably, it is 1 / (1-10). Further, the mixed acid may be three or more. For example, sulfuric acid / acetic acid / propionic acid [mass ratio is preferably 1 / (0.5 to 10) / (0.5 to 10)], methanesulfonic acid / acetic acid / propionic acid [mass ratio is 1 / (0 0.5-10) / (0.5-10) is preferred].

When an acid or a mixed acid is used as a mixed solvent with an organic solvent, a solvent having high solubility with respect to the acid can be added to the organic solvent in order to completely dissolve the acid or the mixed acid. Specifically, water, methanol, ethanol, n-propanol, isopropanol, butyl alcohol, tetrahydrofuran, dimethyl sulfoxide, acetone, ethyl acetate, or the like can be used. The amount of the organic solvent is preferably 30% by mass to 90% by mass with respect to the total amount of the acid solvent.
The acid solvent preferably contains 0.05% by mass or more of water, preferably 0.2% by mass to 50% by mass.

  The amount of the acid used in the mixing step is an amount capable of uniformly dissolving the organic pigment, and is not particularly limited, but an excess amount is preferably used. Regardless of the inorganic acid or organic acid, it is preferably 3 to 500 molar equivalents, more preferably 10 to 500 molar equivalents, still more preferably 30 to 200 molar equivalents relative to the organic pigment.

The mixing step preferably further includes a step of mixing water in addition to the materials A to D described above from the viewpoint of adjusting the dispersibility of the pigment and the physical properties of the obtained pigment dispersion. By the step of mixing water, it is possible to shorten the stirring time when mixing with a poor solvent to form particles. Furthermore, the amount of water to be mixed is preferably 0.5% by mass to 20% by mass, and preferably 1% by mass to 10% by mass with respect to the total amount of the mixed liquid obtained in the mixing step.
As the water to be mixed, for example, pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, distilled water or ultrapure water is preferable. Furthermore, it is preferable to use water sterilized by ultraviolet treatment, hydrogen peroxide treatment or the like for the purpose of preventing the generation of mold, bacteria and the like.

2. Precipitation / dispersion step The precipitation / dispersion step is a poor solvent for the azo pigment, although the pigment solution obtained in the mixing step has compatibility with the acid solvent under the conditions of pH 8-13. This is a step of precipitating fine particles of an azo pigment by mixing an aqueous solvent to obtain a pigment dispersion.

  As the aqueous solvent, a solvent that is compatible with the acid solvent or mixed uniformly as described above and that serves as a poor solvent for the azo pigment is used. As a poor solvent for the azo pigment, the solubility of the azo pigment is preferably 0.02% by mass or less, and more preferably 0.01% by mass or less. There is no particular lower limit to the solubility of the azo pigment in the poor solvent, but 0.000001% by mass or more is practical. This solubility may be the solubility when dissolved in the presence of an acid solvent. In addition, the compatibility or uniform mixing property of the acid solvent and the aqueous solvent is preferably 30% by mass or more, and more preferably 50% by mass or more, with respect to the aqueous solvent. There is no particular upper limit to the amount of acid solvent dissolved in an aqueous solvent, but it is practical to mix the solvent at an arbitrary ratio.

  The aqueous solvent is not particularly limited as long as it is compatible with an acid solvent and the azo pigment is insoluble or hardly soluble. For example, an aqueous solvent (for example, water, hydrochloric acid, aqueous sodium hydroxide), alcohol Compound solvents, ketone compound solvents, ether compound solvents, aromatic compound solvents, carbon disulfide solvents, aliphatic compound solvents, nitrile compound solvents, halogen compound solvents, ester compound solvents, ionic liquids, mixed solvents thereof and the like An aqueous solvent, an alcohol compound solvent, a ketone compound solvent, an ether compound solvent, an ester compound solvent, or a mixture thereof is preferable, and an aqueous solvent, an alcohol compound solvent, or an ester compound solvent is more preferable.

Examples of the alcohol compound solvent include methanol, ethanol, isopropyl alcohol, n-propyl alcohol, 1-methoxy-2-propanol and the like. Examples of the ketone compound solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Examples of the ether compound solvent include dimethyl ether, diethyl ether, tetrahydrofuran, and the like. Examples of the aromatic compound solvent include benzene and toluene. Examples of the aliphatic compound solvent include hexane. Examples of the nitrile compound solvent include acetonitrile. Examples of the halogen compound solvent include chloroform, dichloromethane, trichloroethylene, iodoform, and the like. Examples of the ester compound solvent include ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, 2- (1-methoxy) propyl acetate and the like. The ionic liquids, for example, 1-butyl-3-methylimidazolium and PF ₆ ^-, etc. and salts thereof.

  There are no particular limitations on the conditions of the aqueous solvent as the poor solvent when performing the precipitation / dispersion step, and a range from normal pressure to subcritical and supercritical conditions can be selected. The temperature at normal pressure is preferably −30 to 100 ° C., more preferably −10 to 60 ° C., and particularly preferably 0 to 30 ° C.

  The precipitation / dispersion step is performed under conditions of pH 8-13. By setting the pH value within this range, the azo pigment can be precipitated with a desired particle size. The pH adjuster used for adjusting the pH value is not particularly limited as long as the pH can be adjusted to a desired value without adversely affecting the production process and the resulting pigment dispersion. For example, alcohol amines ( For example, diethanolamine, triethanolamine, 2-amino-2-ethyl-1,3-propanediol, etc.), alkali metal hydroxide (eg, lithium hydroxide, sodium hydroxide, potassium hydroxide, etc.), ammonium hydroxide (For example, ammonium hydroxide, quaternary ammonium hydroxide), phosphonium hydroxide, alkali metal carbonate and the like.

  Moreover, the preparation scale at the time of producing | generating an azo pigment microparticles | fine-particles is although it does not specifically limit, It is preferable that the mixing amount of an aqueous solvent is 1-1000L, and it is more preferable that it is a 1-500L preparation scale.

<Water-based pigment dispersion>
The aqueous pigment dispersion of the present invention produced by the production method of the present invention includes an azo pigment represented by the general formula (1), a surfactant, a water-insoluble polymer, and a solvent. For example, the volume average particle diameter (Mv ) Is as small as 40 to 120 nm, and the particle size distribution width is preferably very narrow such that the polydispersity index (PDI) is in the range of 1.0 to 1.6. Here, the polydispersity index (PDI) is PDI = (D ₉₀ -D ₁₀ ) / D ₅₀ (where D ₉₀ , D ₅₀ , and D ₁₀ are distribution functions dG = F (D) dD (G Is a particle whose integration is equal to 0.9 (90 number%), 0.5 (50 number%) and 0.1 (10 number%) of the total number of pigment particles. Represents the diameter. ] Is obtained from the following formula. That is, in the above relational expression, as the particle size distribution is narrower, the PDI approaches zero, and conversely, the wider the particle size distribution, that is, the greater the polydispersity, the larger the PDI.

Since the aqueous pigment dispersion of the present invention is produced by the production method of the present invention, the volume average particle diameter is small. In addition, since the particle size distribution width is narrow, there is an advantage that coarse particles are hardly settled and fine particles are not easily aggregated, storage stability and ejection properties are excellent, and solvent resistance is excellent.
The water-based pigment dispersion of the present invention is not particularly limited with respect to the content of coarse particles, but from the viewpoint of ejection properties, transparency and storage stability, the number concentration of coarse particles having a particle diameter of 0.5 μm or more. Is preferably 0 piece / ml or more and less than 1.2 × 10 ⁷ pieces / ml, more preferably 0 piece / ml or more and less than 5.0 × 10 ⁶ pieces / ml.

<Water-based ink for inkjet recording>
Next, the water-based ink for inkjet recording of the present invention will be described. The aqueous ink for inkjet recording of the present invention (hereinafter sometimes referred to as “ink”) includes the aqueous pigment dispersion of the present invention and an aqueous medium.

The content ratio of the aqueous pigment dispersion in the ink of the present invention is not particularly limited, but it is 1 to 100% by mass in consideration of the hue, color density, saturation, transparency, etc. of the image formed on the recording medium. A range of 3 to 20% by mass is particularly preferable, and a range of 3 to 10% by mass is most preferable.
The pigment content of the ink of the present invention is, for example, 0.1% by mass to 20% by mass, preferably 0.2% by mass to 10% by mass, and more preferably 1% by mass to 10% by mass. As described above, the water-based ink for ink jet of the present invention using a specific azo pigment can obtain a good print density even if the pigment content is small.

-Aqueous medium The aqueous ink for inkjet recording of the present invention comprises an aqueous medium. Examples of the aqueous medium include those similar to the above dispersion medium such as pure water and ultrapure water, and water-soluble organic solvents. Water-soluble organic solvents are used for the purpose of drying inhibitors, wetting agents or penetration enhancers.
An anti-drying agent is used for the purpose of preventing clogging due to drying of the ink at the ink ejection port of the nozzle, and a water-soluble organic solvent having a vapor pressure lower than that of water is preferable as the anti-drying agent or wetting agent. In addition, a water-soluble organic solvent is preferably used as a penetration accelerator for the purpose of allowing the ink to penetrate better into paper.

  Examples of water-soluble organic solvents include glycerin, 1,2,6-hexanetriol, trimethylolpropane, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, dipropylene glycol, polyoxyethylene Glyceryl ether, polyoxypropylene glyceryl ether, 2-butene-1,4-diol, 2-ethyl-1,3-hexanediol, 2-methyl-2,4-pentanediol, 1,2-octanediol, 1, Alkanediols (polyhydric alcohols) such as 2-hexanediol, 1,2-pentanediol, 4-methyl-1,2-pentanediol; vulcose, mannose, fructose, ribose, xylose, arabino Sugars such as sugar, galactose, aldonic acid, glucitol, (sorbitol), maltose, cellobiose, lactose, sucrose, trehalose, maltotriose; sugar alcohols; peeralonic acids; so-called solid wetting agents such as ureas; ethanol, methanol, C1-C4 alkyl alcohols such as butanol, propanol, isopropanol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono -N-propyl ether, ethylene glycol mono-iso-propyl ether, die Lenglycol mono-iso-propyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-t-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether , Propylene glycol mono-n-propyl ether, propylene glycol mono-iso-propyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-iso-propyl Glycol ethers such as ether; 2-pyrrolidone, N-methyl-2-pyrrolidone, 1 , 3-dimethyl-2-imidazolidinone, formamide, acetamide, dimethyl sulfoxide, sorbit, sorbitan, acetin, diacetin, triacetin, sulfolane and the like, and one or more of these can be used.

  Polyol compounds are useful for the purpose of drying inhibitors and wetting agents, such as glycerin, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butanediol, 2 , 3-butanediol, 1,4-butanediol, 3-methyl-1,3-butanediol, 1,5-pentanediol, tetraethylene glycol, 1,6-hexanediol, 2-methyl-2,4- Examples include pentanediol, polyethylene glycol, 1,2,4-butanetriol, 1,2,6-hexanetriol, and the like. These may be used individually by 1 type and may use 2 or more types together.

  For the purpose of the penetrant, a polyol compound is preferable. Examples of the aliphatic diol include 2-ethyl-2-methyl-1,3-propanediol, 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-hexane Examples include diol, 5-hexene-1,2-diol, and 2-ethyl-1,3-hexanediol. Among these, preferred examples include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.

The aqueous medium used in the present invention may be used alone or in combination of two or more. Preferable examples of the aqueous medium include glycerin, dipropylene glycol, polyoxyethylene glyceryl ether, and polyoxypropylene glyceryl ether.
The content of the aqueous solvent or water-soluble organic solvent is preferably 5 to 60% by mass, more preferably 10 to 40% by mass.
Although there is no restriction | limiting in particular in the addition amount of the water used for this invention, Preferably it is 10 to 99 mass%, More preferably, it is 30 to 80 mass%. More preferably, it is 50 mass% or more and 70 mass% or less.

Other components The ink of the present invention may contain other additives. Other additives include, for example, ultraviolet absorbers, anti-fading agents, anti-mold agents, pH adjusters, rust inhibitors, antioxidants, emulsion stabilizers, preservatives, antifoaming agents, viscosity modifiers, and dispersion stabilizers. Known additives such as agents and chelating agents are included.

  Examples of the UV absorber include benzophenone UV absorbers, benzotriazole UV absorbers, salicylate UV absorbers, cyanoacrylate UV absorbers, nickel complex salt UV absorbers, and the like.

  As the antifading agent, various organic and metal complex antifading agents can be used. Organic anti-fading agents include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, heterocycles, etc. Complex, zinc complex and the like.

  Antifungal agents include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, p-hydroxybenzoic acid ethyl ester, 1,2-benzisothiazolin-3-one, sodium sorbate, sodium pentachlorophenol, etc. Can be mentioned. These are preferably used in the ink in an amount of 0.02 to 1.00% by mass.

  Examples of the rust inhibitor include acidic sulfite, sodium thiosulfate, ammonium thiodiglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

  Examples of the antioxidant include phenol antioxidants (including hindered phenol antioxidants), amine antioxidants, sulfur antioxidants, phosphorus antioxidants, and the like.

  Examples of the chelating agent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uramil diacetate and the like.

-Resin fine particles The ink of the present invention may contain resin fine particles or polymer latex. As resin fine particles or polymer latex, acrylic resin, vinyl acetate resin, styrene-butadiene resin, vinyl chloride resin, acrylic-styrene resin, butadiene resin, styrene resin, crosslinked acrylic resin, crosslinked styrene resin Benzoguanamine resin, phenol resin, silicone resin, epoxy resin, urethane resin, paraffin resin, fluorine resin, and the like can be used. Preferred examples include acrylic resins, acrylic-styrene resins, styrene resins, cross-linked acrylic resins, and cross-linked styrene resins.

  Preferable examples of the resin fine particles include self-dispersing polymer fine particles. Self-dispersing polymer fine particles are vinyl polymers that can be dispersed in an aqueous medium by a functional group (particularly an acidic group or a salt thereof) of the polymer itself in the absence of other surfactants, It means vinyl polymer fine particles that do not contain free emulsifiers. Here, the dispersed state means both an emulsified state (emulsion) in which a vinyl polymer is dispersed in an aqueous medium and a dispersed state (suspension) in which a vinyl polymer is dispersed in a solid state in an aqueous medium. Is included. In the present invention, the vinyl polymer is preferably a vinyl polymer that can be dispersed in a solid state.

  The self-dispersing polymer fine particles preferably used in the present invention preferably contain a vinyl polymer containing a hydrophilic structural unit and a structural unit derived from an aromatic group-containing monomer from the viewpoint of self-dispersibility.

  The hydrophilic structural unit is not particularly limited as long as it is derived from a hydrophilic group-containing monomer, and even if it is derived from one kind of hydrophilic group-containing monomer, it contains two or more hydrophilic groups. It may be derived from a monomer. The hydrophilic group is not particularly limited, and may be a dissociable group or a nonionic hydrophilic group. The hydrophilic group is preferably a dissociable group and more preferably an anionic dissociative group from the viewpoint of promoting self-dispersion and the stability of the formed emulsified or dispersed state. Examples of the dissociable group include a carboxyl group, a phosphoric acid group, and a sulfonic acid group. Among them, a carboxyl group is preferable from the viewpoint of fixability when an ink composition is configured. Examples of the dissociable group-containing monomer include an unsaturated carboxylic acid monomer, an unsaturated sulfonic acid monomer, and an unsaturated phosphoric acid monomer.

Specific examples of the unsaturated carboxylic acid monomer include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, and 2-methacryloyloxymethyl succinic acid. Specific examples of the unsaturated sulfonic acid monomer include styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, 3-sulfopropyl (meth) acrylate, and bis- (3-sulfopropyl) -itaconate. It is done.
Specific examples of unsaturated phosphoric acid monomers include vinylphosphonic acid, vinyl phosphate, bis (methacryloxyethyl) phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, dibutyl-2- Examples include acryloyloxyethyl phosphate. From the viewpoints of dispersion stability and ejection stability, unsaturated carboxylic acid monomers are preferred, and acrylic acid and methacrylic acid are more preferred.

  The aromatic group-containing monomer is not particularly limited as long as it is a compound containing an aromatic group and a polymerizable group. The aromatic group may be a group derived from an aromatic hydrocarbon or a group derived from an aromatic heterocycle. From the viewpoint of particle shape stability in an aqueous medium, an aromatic group derived from an aromatic hydrocarbon is preferable. The polymerizable group may be a condensation polymerizable polymerizable group or an addition polymerizable polymerizable group. In the present invention, from the viewpoint of particle shape stability in an aqueous medium, an addition polymerizable group is preferable, and a group containing an ethylenically unsaturated bond is more preferable.

  The aromatic group-containing monomer is preferably a monomer having an aromatic group derived from an aromatic hydrocarbon and an ethylenically unsaturated bond, and more preferably an aromatic group-containing (meth) acrylate monomer. Examples of the aromatic group-containing monomer include phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, and a styrene monomer. Among them, from the viewpoint of the balance between the hydrophilicity and hydrophobicity of the polymer chain and the ink fixing property, it is preferably at least one selected from phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, and phenyl (meth) acrylate. More preferred is phenoxyethyl (meth) acrylate, and particularly preferred is phenoxyethyl acrylate.

  “(Meth) acrylate” means acrylate or methacrylate. The self-dispersing polymer fine particles include a structural unit derived from an aromatic group-containing (meth) acrylate monomer, and the content is preferably 10% by mass to 95% by mass. When the content of the aromatic group-containing (meth) acrylate monomer is 10% by mass to 95% by mass, the stability of the self-emulsification or dispersion state can be improved, and further the increase in ink viscosity can be suppressed. From the viewpoints of stability in a self-dispersing state, stabilization of particle shape in an aqueous medium due to hydrophobic interaction between aromatic rings, and reduction in the amount of water-soluble components due to appropriate hydrophobicity of particles, 15% by mass to 90% by mass. %, More preferably 15% by mass to 80% by mass, and particularly preferably 25% by mass to 70% by mass.

The self-dispersing polymer fine particles can be composed of, for example, a structural unit composed of an aromatic group-containing monomer and a structural unit composed of a dissociable group-containing monomer, but further includes other structural units as necessary. Can be configured.
The monomer that forms the other structural unit is not particularly limited as long as it is a monomer copolymerizable with the aromatic group-containing monomer and the dissociable group-containing monomer. Among these, an alkyl group-containing monomer is preferable from the viewpoint of flexibility of the polymer skeleton and ease of control of the glass transition temperature (Tg).

  Examples of the alkyl group-containing monomer include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, alkyl (meth) acrylates such as t-butyl (meth) acrylate, hexyl (meth) acrylate, ethylhexyl (meth) acrylate; hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) Ethylenically unsaturated monomers having a hydroxyl group such as acrylate, 4-hydroxybutyl (meth) acrylate, hydroxypentyl (meth) acrylate, hydroxyhexyl (meth) acrylate; Dialkylaminoalkyl (meth) acrylates such as ru (meth) acrylate; N-hydroxyalkyl (meth) such as N-hydroxymethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N-hydroxybutyl (meth) acrylamide Acrylamide; N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, N- (n-, iso) butoxymethyl (meth) acrylamide, N-methoxyethyl (meth) acrylamide, N-ethoxyethyl (meta And (meth) acrylamides such as N-alkoxyalkyl (meth) acrylamides such as acrylamide and N- (n-, iso) butoxyethyl (meth) acrylamide.

  The molecular weight range of the vinyl polymer constituting the self-dispersing fine polymer particles in the present invention is preferably 3000 to 200,000, more preferably 5000 to 150,000, and more preferably 10,000 to 100,000 in terms of mass average molecular weight. More preferably. By setting the mass average molecular weight to 3000 or more, the amount of water-soluble components can be effectively suppressed. Moreover, self-dispersion stability can be improved by making a mass average molecular weight into 200,000 or less.

  The mass average molecular weight can be measured by gel permeation chromatography (GPC).

  From the viewpoint of controlling the hydrophilicity / hydrophobicity of the polymer, the vinyl polymer that constitutes the self-dispersing polymer fine particles is an aromatic group-containing (meth) acrylate monomer as a copolymerization ratio of 15 to 90% by mass, a carboxyl group-containing monomer, and an alkyl group-containing monomer. It is preferable that the acid value is 25 to 100 and the mass average molecular weight is 3000 to 200,000, and 15 to 80% by mass as a copolymerization ratio of an aromatic group-containing (meth) acrylate monomer and a carboxyl group More preferably, it contains a monomer containing and an alkyl group-containing monomer, has an acid value of 25 to 95, and a mass average molecular weight of 5000 to 150,000.

  The average particle size of the self-dispersing polymer fine particles is preferably in the range of 10 nm to 1 μm, more preferably in the range of 10 to 200 nm, still more preferably in the range of 20 to 100 nm, and particularly preferably in the range of 20 to 50 nm.

The addition amount of the self-dispersing polymer fine particles is preferably 0.5 to 20% by mass, more preferably 3 to 20% by mass, and still more preferably 5 to 15% by mass with respect to the ink.
The glass transition temperature Tg of the self-dispersing polymer fine particles is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, and further preferably 50 ° C. or higher.
Further, the particle size distribution of the polymer particles is not particularly limited, and may be any having a wide particle size distribution or a monodispersed particle size distribution. Further, two or more kinds of polymer fine particles having a monodispersed particle size distribution may be mixed and used.

-Liquid composition which improves printability In this invention, it can mention as a preferable example that the liquid composition which improves printability is provided to a printing medium.
A preferred example of the liquid composition that can be used in the present invention to improve the printability is a liquid composition that generates an aggregate by changing the pH of the ink. At this time, the pH of the liquid composition is preferably 1 to 6, more preferably 2 to 5, and still more preferably 3 to 5. As components of the liquid composition, polyacrylic acid, acetic acid, glycolic acid, malonic acid, malic acid, maleic acid, ascorbic acid, succinic acid, glutaric acid, fumaric acid, citric acid, tartaric acid, lactic acid, sulfonic acid, orthophosphoric acid, It is preferably selected from pyrrolidone carboxylic acid, pyrone carboxylic acid, pyrrole carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, nicotinic acid, derivatives of these compounds, or salts thereof. . These compounds may be used alone or in combination of two or more.

  A preferred example of a liquid composition that can be used in the present invention to improve printability is a treatment liquid to which a polyvalent metal salt or polyallylamine is added. As a component of the liquid composition, as a polyvalent metal salt, an alkaline earth metal of Group 2A of the periodic table (for example, magnesium and calcium); a transition metal of Group 3B of the periodic table (for example, lanthanum); from Group 3A of the periodic table Cations (for example, aluminum); lanthanides (for example, neodymium); and polyallylamine and polyallylamine derivatives. Preferred examples include calcium and magnesium. Anions that are preferably employed as a counter salt of calcium or magnesium include carboxylate (formic acid, acetic acid, benzoate, etc.), nitrate, chloride, and thiocyanate. The amount of the salt added to the treatment liquid is about 1 to about 10% by weight, preferably about 1.5 to about 7% by weight, more preferably about 2 to about 6% by weight in the treatment liquid. Can exist.

  The aqueous medium used in the present invention may be used alone or in combination of two or more. The content of the aqueous medium is 1% by mass or more and 60% by mass or less, preferably 5% by mass or more and 40% by mass or less of the whole ink. When the amount of the aqueous medium in the ink is less than 1% by mass, a sufficient optical density may not be obtained. Conversely, when the amount is more than 60% by mass, the viscosity of the liquid increases, There are cases where the ejection characteristics of the ink liquid become unstable.

Ink physical properties Preferred physical properties of the ink of the present invention are as follows. The surface tension of the ink is preferably 20 mN / m or more and 60 mN / m or less. More preferably, it is 20 mN or more and 45 mN / m or less, More preferably, it is 25 mN / m or more and 35 mN / m or less. If the surface tension is less than 20 mN / m, liquid may overflow on the nozzle surface of the recording head, and printing may not be performed normally. On the other hand, if it exceeds 60 mN / m, the permeability to the recording medium after printing may be slow, and the drying time may be slow.
The surface tension was measured under the environment of 23 ° C. and 55% RH using a Wilhelmy surface tension meter as described above.

The viscosity of the ink is preferably from 1.2 mPa · s to 8.0 mPa · s, more preferably from 1.5 mPa · s to less than 6.0 mPa · s, still more preferably from 1.8 mPa · s to 4. It is less than 5 mPa · s. When the viscosity is greater than 8.0 mPa · s, the dischargeability may be reduced. On the other hand, when it is smaller than 1.2 mPa · s, the long-term jetting property may deteriorate.
The viscosity (including those described later) was measured using a rotational viscometer Rheomat 115 (manufactured by Contraves) at 23 ° C. and a shear rate of 1400 s ⁻¹ .

  In addition to the components described above, water is added to the ink in the range of the above-described preferable surface tension and viscosity. The amount of water added is not particularly limited, but is preferably 10% by mass to 99% by mass, and more preferably 30% by mass to 80% by mass with respect to the entire ink.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples at all. In addition, “parts” and “%” in the description mean parts by mass and mass% unless otherwise specified.

[Synthesis Example 1]
(Synthesis of pigment)
Synthesis of Exemplary Compound (Pig.-1) A synthesis scheme of exemplary compound (Pig.-1) is shown below.

(1) Synthesis of intermediate (a) 29.7 g (0.3 mol) of methyl cyanoacetate, 42.4 g (0.4 mol) of trimethyl orthoformate, 20.4 g (0.2 mol) of acetic anhydride, p- Toluenesulfonic acid 0.5 g was added and heated to 110 ° C. (external temperature), and the mixture was stirred for 20 hours while distilling off low-boiling components generated from the reaction system. The reaction solution was concentrated under reduced pressure, and then purified on a silica gel column to obtain 14.1 g of the intermediate (a) (yellow powder, yield 30%). The NMR measurement result of the obtained intermediate (a) is as follows.
¹ H-NMR (300 MHz, CDCl ₃ ) 7.96 (s, 1H), 4.15 (s, 3H), 3.81 (s, 3H)

(2) Synthesis of Intermediate (b) 150 mL of isopropanol was added to 7.4 mL (141 mmol) of methyl hydrazine and cooled to 15 ° C. (internal temperature), and 7.0 g (49. 6 mmol) was gradually added, and the mixture was heated to 50 ° C. and stirred for 1 hour and 40 minutes. The reaction solution was concentrated under reduced pressure, and then purified on a silica gel column to obtain 10.5 g of the intermediate (b) (white powder, yield 50%). The NMR measurement result of the obtained intermediate (b) is as follows.
¹ H-NMR (300 MHz, CDCl ₃ ) 7.60 (s, 1H), 4.95 (brs, 2H), 3.80 (s, 3H), 3.60 (s, 3H)

(3) Synthesis of Intermediate (c) 298 mL of methanol was added to 387 mL (7.98 mol) of hydrazine monohydrate and cooled to 10 ° C. (internal temperature), and 149 g of 4,6-dichloropyrimidine was added to this mixed solution ( 1.00 mol) was gradually added (internal temperature 20 ° C. or lower), the ice bath was removed, the temperature was raised to room temperature, and the mixture was stirred at the same temperature for 30 minutes. Thereafter, the mixture was further heated to raise the internal temperature to 60 ° C. and stirred at the same temperature for 5 hours. After completion of the reaction, 750 mL of water was added, and the mixture was cooled with ice and cooled to an internal temperature of 8 ° C. The precipitated crystals were collected by filtration, washed with water, and washed with isopropanol. It dried at room temperature for 36 hours, and obtained the said intermediate body (c) by 119g (white powder, yield 84.5%). The NMR measurement result of the obtained intermediate (c) is as follows.
¹ H-NMR (300 MHz, d-DMSO) 7.80 (s, 1H), 7.52 (s, 2H), 5.98 (s, 1H), 4.13 (s, 4H)

(4) Synthesis of Intermediate (d) To 50 g (357 mmol) of Intermediate (c), 128 mL of water was added and stirred at room temperature. To this suspension, 98.2 g (785 mmol) of pivaloylacetonitrile was added, and 12 M hydrochloric acid aqueous solution was added dropwise at the same temperature so that the pH became 3, and then the mixture was heated to an internal temperature of 50 ° C. For 6 hours. After completion of the reaction, the solution was neutralized by adding 8N aqueous potassium hydroxide solution to pH 6.4. The mixture was cooled with ice and cooled to an internal temperature of 10 ° C., and the precipitated crystals were collected by filtration and washed with water. The obtained crystal was dried at 60 ° C. under reduced pressure, and 30 mL of toluene was added to the obtained crude product, and heated to 60 ° C. for dissolution. The obtained solution was allowed to stand at room temperature for 12 hours, and the precipitated crystals were collected by filtration, washed with cooled toluene and dried at 60 ° C. under reduced pressure, and 87.7 g of the intermediate (d) (white powder) Yield 69.3%). The NMR measurement result of the obtained intermediate (d) is as follows.
¹ H-NMR (300 MHz, d-DMSO) 8.74 (s, 1H), 7.99 (s, 1H), 6.87 (s, 4H), 5.35 (s, 2H), 1.24 (S, 18H)

(5) Synthesis of Exemplary Compound (Pig.-1) 9.2 g of the intermediate (b) was dissolved in a mixed solution of 55 mL of acetic acid and 37 mL of propionic acid at room temperature. The inner temperature was cooled to -3 ° C by cooling with ice, and a 40 mass% sulfuric acid solution of nitrosylsulfuric acid was added dropwise over 10 minutes at an inner temperature of -3 ° C to 4 ° C. After stirring for 1 hour at an internal temperature of 4 ° C., 0.2 g of urea was added, and then the internal temperature was cooled to −3 ° C. and further stirred for 10 minutes to obtain a diazonium salt solution. Separately, 10 g of the intermediate (d) was completely dissolved in 150 mL of acetone, and then the internal temperature was cooled to 17 ° C. and added to the above diazonium salt solution over 25 minutes within the range of the internal temperature of −3 ° C. to 3 ° C. . After completion of the addition, the mixture was stirred at 3 ° C. for 30 minutes, then the ice bath was removed and the temperature was raised to room temperature over 30 minutes. After stirring at room temperature for 30 minutes, the obtained crystals were filtered off, washed with 150 mL of acetone, and further washed with 100 mL of water. The obtained crystals were suspended in 400 mL of water without drying, and an aqueous 8N potassium hydroxide solution was added to adjust the pH to 5.7. After stirring at room temperature for 20 minutes, the obtained crystals were separated by filtration, thoroughly washed with water, and then washed with 80 mL of acetone. The obtained crystal was dried at room temperature for 12 hours.

The obtained crystals were suspended in 580 mL of acetone and then stirred for 30 minutes under reflux. Then, it cooled to room temperature over 10 minutes, the obtained crystal was separated by filtration, and it was made to dry at room temperature for 5 hours, and 18.0g of exemplary compound (Pig.-1) was obtained. Yield 93.1%.
As a measurement of the average primary particle diameter by observation with a transmission electron microscope (TEM), a diluted dispersion was dropped onto a Cu200 mesh with a carbon film attached, and then dried, and then magnified 100,000 times with TEM (1200 JEOL). From the obtained images, an average value obtained by measuring the major axis of 300 independent particles not overlapping was calculated as an average primary particle size (hereinafter, the average primary particle size calculated by TEM observation is simply referred to as an average primary particle size). . It was 880 nm when the average primary particle diameter of the obtained pigment was measured.

[Synthesis Example 2]
(Synthesis of pigment)
Synthesis of Exemplary Compound (Pig.-18) A synthesis scheme of exemplary compound (Pig.-18) is shown below.

(1) Synthesis of intermediate (a) 29.7 g (0.3 mol) of methyl cyanoacetate, 42.4 g (0.4 mol) of trimethyl orthoformate, 20.4 g (0.2 mol) of acetic anhydride, p- Toluenesulfonic acid 0.5 g was added and heated to 110 ° C. (external temperature), and the mixture was stirred for 20 hours while distilling off low-boiling components generated from the reaction system. The reaction solution was concentrated under reduced pressure, and then purified on a silica gel column to obtain 14.1 g of the intermediate (a) (yellow powder, yield 30%). The NMR measurement result of the obtained intermediate (a) is as follows.
¹ H-NMR (300 MHz, CDCl ₃ ) 7.96 (s, 1H), 4.15 (s, 3H), 3.81 (s, 3H)

(2) Synthesis of Intermediate (b) 150 mL of isopropanol was added to 7.4 mL (141 mmol) of methyl hydrazine and cooled to 15 ° C. (internal temperature), and 7.0 g (49. 6 mmol) was gradually added, and the mixture was heated to 50 ° C. and stirred for 1 hour and 40 minutes. The reaction solution was concentrated under reduced pressure, and then purified on a silica gel column to obtain 10.5 g of the intermediate (b) (white powder, yield 50%). The NMR measurement result of the obtained intermediate (b) is as follows.
¹ H-NMR (300 MHz, CDCl ₃ ) 7.60 (s, 1H), 4.95 (brs, 2H), 3.80 (s, 3H), 3.60 (s, 3H)

(3) Synthesis of intermediate (c ′) 136 mL of water was added to 1.1 L of methanol, 182 g (2.17 mol) of sodium bicarbonate was added, and the mixture was stirred at room temperature. At the same temperature, 200 g (1.08 mol) of cyanuric chloride was added in portions. After the addition, the internal temperature was raised to 30 ° C. After stirring at the same temperature for 30 minutes, 500 mL of water was added, the precipitated solid was filtered, washed with 500 mL of water and 300 mL of methanol, dried, and 168 g of the intermediate (c ′) (white powder, collected). 86.2%). The NMR measurement result of the obtained intermediate (c ′) is as follows.
¹ H-NMR (300 MHz, CDCl ₃ ) 4.14 (s, 3H)

(4) Synthesis of intermediate (d ′) 673 mL of water was added to 363 mL (7.46 mol) of hydrazine monohydrate and cooled to 10 ° C. (internal temperature), and 168 g of intermediate (c ′) was added to this mixture. (934 mmol) was gradually added (internal temperature 20 ° C. or lower), the ice bath was removed, the temperature was raised to room temperature, and the mixture was stirred at the same temperature for 30 minutes. The crystals precipitated from the reaction solution were collected by filtration, washed with 700 mL of water and 1 L of acetonitrile, and then dried to obtain a crude product (white powder) of the intermediate (d ′).

(5) Synthesis of Intermediate (e) 480 mL of ethylene glycol was added to the loosely purified product of Intermediate (d ′) and stirred at room temperature. To this suspension, 257 g (2.06 mol) of pivaloyl acetonitrile was added and heated until the internal temperature reached 50 ° C. After dropwise addition of 12M aqueous hydrochloric acid at the same temperature to pH 3, the mixture was heated to an internal temperature of 80 ° C. and stirred for 3 hours. After completion of the reaction, the mixture was ice-cooled and cooled to an internal temperature of 8 ° C. The precipitated crystals were collected by filtration, washed with water, and purified by silica gel column. 105g of the intermediate (e) (white powder, 2 steps) (Yield 29.2%). The NMR measurement result of the obtained intermediate (e) is as follows.
¹ H-NMR (300 MHz, d-DMSO) 7.00 (s, 4H), 5.35 (s, 2H), 4.05 (s, 3H), 5.35 (s, 2H), 1.22 (S, 18H)

(6) Synthesis of Exemplary Compound (Pig.-18) A mixture of 125 mL of acetic acid and 24 mL of sulfuric acid was ice-cooled, and the internal temperature was cooled to 3 ° C. At the same temperature, 26.4 g of nitrosylsulfuric acid was added, and subsequently, 11.6 g of intermediate (b) was dividedly added and dissolved at the same temperature. After stirring for 1 hour at the same temperature, 1.2 g of urea was added in portions at the same temperature and stirred for 15 minutes at the same temperature to obtain a diazonium salt solution. Separately, 11.6 g of intermediate (e) was completely dissolved in 405 mL of methanol at room temperature, and ice-cooled to cool the internal temperature to -3 ° C. At the same temperature, the above-described diazonium salt solution was added in portions so that the internal temperature was 3 ° C. or less, and stirred for 2 hours after the addition was completed. After removing the ice bath and stirring at room temperature for 10 minutes, the precipitated crystals were separated by filtration, washed with 150 mL of methanol, and further washed with 100 mL of water. The obtained crystals were suspended in 750 mL of water without drying, and 8N aqueous potassium hydroxide solution was added to adjust the pH to 5.7. After stirring at room temperature for 20 minutes, the obtained crystals were separated by filtration, thoroughly washed with water, and then washed with 80 mL of methanol. The obtained crystals were dried at room temperature for 12 hours to obtain 20.3 g of exemplary compound (Pig.-18). Yield 94.0%
The obtained exemplary compound (Pig.-18) was adjusted to ethanol / water, and the average primary particle size was measured with a transmission microscope TEM (JEOL 1200EX), and it was 1100 nm.

[Synthesis Example 3]
(Synthesis of water-insoluble polymer (P-1))
Mixing so that the total amount of the three components of the following monomer composition is 100 parts by mass, and further adding 1 part by mass of 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator, sufficiently replacing nitrogen gas To obtain a synthesis mixture.

Phenoxyethyl methacrylate 50 parts by weight Methyl methacrylate 39 parts by weight Methacrylic acid 11 parts by weight 2-Mercaptoethanol 0.1 part by weight

  Next, 100 parts by mass of methyl ethyl ketone was heated to 75 ° C. with stirring in a nitrogen atmosphere. The synthetic mixture was added dropwise over 3 hours at 75 ° C. with stirring. The reaction was further continued at 75 ° C. with stirring for 5 hours. Thereafter, the reaction product is naturally cooled to 25 ° C. and then diluted by adding methyl ethyl ketone so that the solid content is 40%. The mass average molecular weight (Mw) determined by GPC is 40000, and is JIS standard (JIS K). 0070: 1992), a water-insoluble polymer solution having an acid value of 71.7 mgKOH / g was obtained.

[Synthesis Example 4]
(Synthesis of water-insoluble polymer (P-2))
A vinyl polymer (P-2) solution was obtained in the same manner as in Synthesis Example 1 except that the monomer composition in Synthesis Example 1 was changed to the following monomer composition. A water-insoluble polymer solution having a mass average molecular weight (Mw) determined by GPC of 42000 and an acid value determined by the method described in JIS standard (JIS K 0070: 1992) of 98.3 mgKOH / g was obtained.

Phenoxyethyl methacrylate 50 parts by weight Methyl methacrylate 35 parts by weight Methacrylic acid 15 parts by weight 2-Mercaptoethanol 0.1 part by weight

[Example 1]
1. Preparation of Pigment Solution Each component was prepared with the following composition, and stirred and mixed for 30 minutes to obtain Pigment Solution 1.
Pig. -1 5.00 parts by mass Nitrosylsulfuric acid 40.00 parts by mass Tetrahydrofuran 40.00 parts by mass P-2 6.50 parts by mass Aqualon KH-10 (Daiichi Kogyo Seiyaku Co., Ltd.) 6.00 parts by mass Ultrapure water 50 parts by weight

2. Preparation of water-based pigment dispersion Under high-speed stirring conditions, 100 parts by mass of pigment solution was added into the liquid at a rate of 100 mL / min to 0.1 parts by mass of 0.1 NKOH aqueous solution using a syringe pump, and then stirred for 30 minutes. Carried out. The pH of the obtained dispersion was 12.3.
The resulting liquid was purified and concentrated with an ultrafiltration membrane to obtain an aqueous pigment dispersion 1 having a pigment solid content concentration of 15%. The obtained aqueous pigment dispersion 1 had a pH of 9.0.

3. Preparation of Aqueous Ink for Inkjet Recording Each component was adjusted and stirred so as to have a total of 100 parts by mass with the following composition.
Aqueous pigment dispersion 1 35 parts by mass Glycerin 15 parts by mass
Diethylene glycol monoethyl ether 5 parts by mass Olefin E1010 1 part by mass Ion-exchanged water remaining

[Example 2]
1. Preparation of Pigment Solution Each component was prepared with the following composition and stirred and mixed for 30 minutes to obtain Pigment Solution 2.
Pig. -18 5.00 parts by mass Tetrahydrofuran 40.25 parts by mass Methanesulfonic acid 40.25 parts by mass P-1 6.00 parts by mass Aqualon KH-10 (Daiichi Kogyo Seiyaku Co., Ltd .: surfactant)) 6.00 parts by mass Part ultrapure water 2.50 parts by mass

2. Preparation of water-based pigment dispersion Under high-speed stirring conditions, pigment solution 2: 100 parts by mass is added to a 0.1N NaOH aqueous solution: 1000 parts by mass at 100 mL / min using a syringe pump, and then stirred for 30 minutes. did. The pH of the obtained dispersion was 12.1.
The resulting liquid was purified and concentrated with an ultrafiltration membrane to obtain an aqueous pigment dispersion 1 having a pigment solid content concentration of 15%. The pH of the obtained aqueous pigment dispersion 2 was 9.1.

3. Preparation of water-based ink for inkjet recording Ink 2 was obtained in the same manner as in Example 1 except that the aqueous pigment dispersion 1 was changed to the aqueous pigment dispersion 2.

[Example 3]
1. Preparation of Pigment Solution Each component was prepared with the following composition, and stirred and mixed for 30 minutes to obtain pigment solution 3.
Pig. -1 5.00 parts by mass Tetrahydrofuran 41.25 parts by mass Nitrosylsulfuric acid 41.25 parts by mass P-2 6.50 parts by mass Aqualon KH-10 (Daiichi Kogyo Seiyaku Co., Ltd.) 6.00 parts by mass

2. Preparation of water-based pigment dispersion Under high-speed stirring conditions, 100 parts by mass of pigment solution was added into the liquid at a rate of 100 mL / min to 1000 parts by mass of 0.1NKOH aqueous solution using a syringe pump, and then stirred for 6 hours. did. The pH of the obtained dispersion was 12.2.
The resulting liquid was purified and concentrated with an ultrafiltration membrane to obtain an aqueous pigment dispersion 3 having a pigment solid content concentration of 15%.
The pH of the obtained aqueous pigment dispersion 2 was 8.9.

3. Preparation of Aqueous Ink for Inkjet Recording Ink 3 was obtained in the same manner as in Example 1 except that the aqueous pigment dispersion 1 was changed to the aqueous pigment dispersion 3.

[Example 4]
1. Preparation of Pigment Solution Each component was prepared with the following composition, and stirred and mixed for 30 minutes to obtain pigment solution 4.
Pig. -1 5.00 parts by mass Nitrosylsulfuric acid 40.00 parts by mass Tetrahydrofuran 40.00 parts by mass P-2 6.50 parts by mass Olefin E1010 (surfactant) 6.00 parts by mass Ultrapure water 2.50 parts by mass

2. Preparation of water-based pigment dispersion Under high-speed stirring conditions, 100 parts by mass of pigment solution was added into the solution at a rate of 100 mL / min to 1000 parts by mass of 0.1NKOH aqueous solution using a syringe pump, and then stirred for 30 minutes. did. The pH of the obtained dispersion was 12.0.
The resulting liquid was purified and concentrated with an ultrafiltration membrane to obtain an aqueous pigment dispersion 4 having a pigment solid content concentration of 15%. The obtained aqueous pigment dispersion 4 had a pH of 9.0.

3. Preparation of Water-Based Ink for Inkjet Recording Ink 4 was obtained in the same manner as in Example 1 except that water-based pigment dispersion 1 was changed to water-based pigment dispersion 4.

[Comparative Example 1]
1. Preparation of Pigment Solution Each component was prepared with the following composition and stirred and mixed for 30 minutes to obtain pigment solution 5.
PY74 (CI Pigment Yellow 74)
1.00 parts by mass Tetrahydrofuran 26.25 parts by mass Methanesulfonic acid 58.25 parts by mass P-1 6.00 parts by mass Aqualon KH-10 (Daiichi Kogyo Seiyaku Co., Ltd.) 6.00 parts by mass Ultrapure water 2.50 Parts by mass

2. Preparation of water-based pigment dispersion Under high-speed stirring conditions, pigment solution 5: 100 parts by mass is added into the solution at a rate of 100 mL / min to 0.1 N NaOH aqueous solution: 1000 parts by mass using a syringe pump, and then stirred for 30 minutes. did. The pH of the obtained dispersion was 12.1.
The resulting liquid was purified and concentrated with an ultrafiltration membrane to obtain an aqueous pigment dispersion 5 having a pigment solid content concentration of 15%. The pH of the obtained aqueous pigment dispersion 2 was 9.1.

3. Preparation of Aqueous Ink for Inkjet Recording Ink 5 was obtained in the same manner as in Example 1 except that the aqueous pigment dispersion 1 was changed to the aqueous pigment dispersion 5.

[Comparative Example 2]
1. Preparation of Pigment Solution Each component was prepared with the following composition, and stirred and mixed for 30 minutes to obtain pigment solution 6.
Pig. -1 5.00 parts by weight Dimethyl sulfoxide 78.00 parts by weight Sodium methoxide 5.00 parts by weight P-2 6.00 parts by weight Aqualon KH-10 (Daiichi Kogyo Seiyaku Co., Ltd.) 6.00 parts by weight

2. Preparation of water-based pigment dispersion Under high-speed stirring conditions, pigment solution 6: 100 parts by mass is added into a 0.1N NaOH aqueous solution: 1000 parts by mass at 100 mL / min using a syringe pump, and then stirred for 30 minutes. did. The pH of the obtained dispersion was 12.8.
The resulting liquid was purified and concentrated with an ultrafiltration membrane to obtain an aqueous pigment dispersion 6 having a pigment solid content concentration of 15%.
The obtained aqueous pigment dispersion 6 had a pH of 9.3.

3. Preparation of Aqueous Ink for Inkjet Recording Ink 6 was obtained in the same manner as in Example 1 except that the aqueous pigment dispersion 1 was changed to the aqueous pigment dispersion 6.

[Comparative Example 3]
1. Preparation of pigment solution Each component was prepared with the following composition, and stirred and mixed for 30 minutes.
Pig. -18 5.00 parts by mass Methanol 48.00 parts by mass Sodium ethoxide 28% methanol solution 35.00 parts by mass P-1 6.00 parts by mass Aqualon KH-10 (Daiichi Kogyo Seiyaku Co., Ltd.) 6.00 parts by mass However, a gel-like substance was generated in the liquid, and a uniform solution could not be obtained.

[Comparative Example 4]
1. Preparation of Pigment Solution Each component was prepared with the following composition and stirred and mixed for 30 minutes to obtain pigment solution 8.
Pig. -1 5.00 parts by mass Nitrosylsulfuric acid 40.00 parts by mass Tetrahydrofuran 40.00 parts by mass P-2 6.50 parts by mass Aqualon KH-10 (Daiichi Kogyo Seiyaku Co., Ltd.) 6.00 parts by mass Ultrapure water 50 parts by weight

2. Preparation of water-based pigment dispersion Under high-speed stirring conditions, pigment solution 8: 100 parts by mass is added into the solution at a rate of 100 mL / min to 0.01 NKOH aqueous solution: 1000 parts by mass using a syringe pump, and then stirred for 30 minutes. Carried out. The pH of the obtained dispersion was 1.8.
The resulting liquid was purified and concentrated with an ultrafiltration membrane to obtain an aqueous pigment dispersion 8 having a pigment solid content concentration of 15%. The obtained aqueous pigment dispersion 8 had a pH of 9.3.

3. Preparation of Aqueous Ink for Inkjet Recording Ink 8 was obtained in the same manner as in Example 1 except that the aqueous pigment dispersion 1 was changed to the aqueous pigment dispersion 8.

[Comparative Example 5]
1. Preparation of Pigment Solution Each component was prepared with the following composition, and stirred and mixed for 30 minutes to obtain pigment solution 9.
Pig. -1 5.00 parts by mass Nitrosylsulfuric acid 40.00 parts by mass Tetrahydrofuran 40.00 parts by mass P-2 6.50 parts by mass Aqualon KH-10 (Daiichi Kogyo Seiyaku Co., Ltd.) 6.00 parts by mass Ultrapure water 50 parts by weight

2. Preparation of aqueous pigment dispersion Under high-speed stirring conditions, the pigment solution 9: 100 parts by mass was added to the 1NKOH aqueous solution: 1000 parts by mass at 100 mL / min using a syringe pump, and then stirred for 30 minutes. . The pH of the obtained dispersion was 13.8.
The resulting liquid was purified and concentrated with an ultrafiltration membrane to obtain an aqueous pigment dispersion 9 having a pigment solid content concentration of 15%. The obtained aqueous pigment dispersion 9 had a pH of 8.9.

3. Preparation of Aqueous Ink for Inkjet Recording Ink 9 was obtained in the same manner as in Example 1 except that the aqueous pigment dispersion 1 was changed to the aqueous pigment dispersion 9.

[Comparative Example 6]
1. Preparation of Pigment Solution Each component was prepared with the following composition and stirred and mixed for 30 minutes to obtain pigment solution 10.
Pig. -1 5.00 parts by mass Nitrosylsulfuric acid 40.00 parts by mass Tetrahydrofuran 40.00 parts by mass P-2 6.50 parts by mass Aqualon KH-10 (Daiichi Kogyo Seiyaku Co., Ltd.) 6.00 parts by mass Ultrapure water 50 parts by weight

2. Preparation of aqueous pigment dispersion Under high-speed stirring conditions, 10: 100 parts by mass of pigment solution was added to 1000 parts by mass of ultrapure water at 100 mL / min using a syringe pump, and then stirred for 30 minutes. . The pH of the obtained dispersion was 1.3.
The resulting liquid was purified and concentrated with an ultrafiltration membrane to obtain an aqueous pigment dispersion 10 having a pigment solid content concentration of 15%. The obtained aqueous pigment dispersion 10 had a pH of 9.0.

3. Preparation of Water-Based Ink for Inkjet Recording Ink 10 was obtained in the same manner as in Example 1 except that water-based pigment dispersion 1 was changed to water-based pigment dispersion 10.

[Comparative Example 7]
1. Preparation of Pigment Solution Each component was prepared with the following composition, and stirred and mixed for 30 minutes to obtain pigment solution 11.
Pig. -1 5.00 parts by mass Nitrosylsulfuric acid 43.00 parts by mass Tetrahydrofuran 43.00 parts by mass P-2 6.50 parts by mass Ultrapure water 2.50 parts by mass

2. Preparation of water-based pigment dispersion Under high-speed stirring conditions, pigment solution 11: 100 parts by mass is added to a 0.1 NKOH aqueous solution: 1000 parts by mass at 100 mL / min using a syringe pump, and then stirred for 30 minutes. Carried out. The pH of the obtained dispersion was 12.3.
The resulting liquid was purified and concentrated with an ultrafiltration membrane to obtain an aqueous pigment dispersion 11 having a pigment solid content concentration of 15%. The obtained aqueous pigment dispersion 11 had a pH of 9.2.

3. Preparation of Aqueous Ink for Inkjet Recording Ink 11 was obtained in the same manner as in Example 1 except that the aqueous pigment dispersion 1 was changed to the aqueous pigment dispersion 11.

[Comparative Example 8]
1. Preparation of Pigment Solution Each component was prepared with the following composition, and stirred and mixed for 30 minutes to obtain pigment solution 12.
Pig. -1 5.00 parts by mass Nitrosylsulfuric acid 43.25 parts by mass Tetrahydrofuran 43.25 parts by mass Aqualon KH-10 (Daiichi Kogyo Seiyaku Co., Ltd.) 6.00 parts by mass Ultrapure water 2.50 parts by mass

2. Preparation of Aqueous Pigment Dispersion Under high speed stirring conditions, add 100 parts by weight of pigment solution to 100 parts by weight of 0.1 NKOH aqueous solution using a syringe pump at 100 mL / min, and then stir for 30 minutes. Carried out. The pH of the obtained dispersion was 12.2.
The resulting liquid was purified and concentrated with an ultrafiltration membrane to obtain an aqueous pigment dispersion 12 having a pigment solid content concentration of 15%. The pH of the obtained aqueous pigment dispersion 12 was 9.0.

3. Preparation of Aqueous Ink for Inkjet Recording Ink 12 was obtained in the same manner as in Example 1 except that the aqueous pigment dispersion 1 was changed to the aqueous pigment dispersion 12.

[Evaluation]
(Ink storage stability)
Each prepared ink was put in a PET container, sealed, and stored in a thermostatic bath at 70 ° C. for 5 days, and the viscosity and average particle diameter before and after storage were measured. Further, the viscosity and average particle diameter of the pigment-containing vinyl polymer particle aqueous dispersion before storage were also measured by the same method. The viscosity was measured with an R100 viscometer (manufactured by Toki Sangyo Co., Ltd.) at 25 ° C. and a cone rotation speed of 20 to 100 rpm. The average particle size was measured by dynamic light scattering method using a nanotrack particle size distribution analyzer UPA-EX150 (manufactured by Nikkiso Co., Ltd.), volume average particle size Mv, cumulative 90% particle size (D ₉₀ ), cumulative 50% particle. The diameter (D ₅₀ ) and the cumulative 10% particle diameter (D ₁₀ ) were measured.
PDI = (D ₉₀ -D ₁₀ ) / D ₅₀ (where D ₉₀ , D ₅₀ and D ₁₀ are integrals of the distribution function dG = F (D) dD (G is the number of pigment particles, D is the particle size), respectively) Represents a particle diameter equal to 0.9 (90 number%), 0.5 (50 number%) and 0.1 (10 number%) of the total number of pigment particles. ], PDI was calculated.
Using each measured value as an index, the stability of the pigment-containing vinyl polymer particle aqueous dispersion was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1.

<Evaluation criteria>
A: Viscosity, average particle diameter and PDI are all less than ± 10% of the values before storage.
B: Any of viscosity, average particle diameter and PDI is ± 10% or more of the value before storage.
C: Viscosity, average particle diameter and PDI are ± 10% or more of the values before storage.

(Solvent resistance of ink)
15 parts by mass of triethylene glycol monobutyl ether is added to 75 parts by mass of each ink prepared, and the resulting mixture is sealed in a PET container and stored in a thermostatic bath at 60 ° C. for 14 days. And the average particle diameter was measured. Further, the viscosity and average particle diameter of the ink before storage were also measured by the same method. The viscosity was measured with an R100 viscometer (manufactured by Toki Sangyo Co., Ltd.) at 25 ° C. and a cone rotation speed of 20 to 100 rpm. The average particle size was measured by dynamic light scattering method using a nanotrack particle size distribution analyzer UPA-EX150 (manufactured by Nikkiso Co., Ltd.), volume average particle size Mv, cumulative 90% particle size (D ₉₀ ), cumulative 50% particle. The diameter (D ₅₀ ) and the cumulative 10% particle diameter (D ₁₀ ) were measured.
PDI = (D ₉₀ -D ₁₀ ) / D ₅₀ (where D ₉₀ , D ₅₀ and D ₁₀ are integrals of the distribution function dG = F (D) dD (G is the number of pigment particles, D is the particle size), respectively) Represents a particle diameter equal to 0.9 (90 number%), 0.5 (50 number%) and 0.1 (10 number%) of the total number of pigment particles. ], PDI was calculated.
Using each measured value as an index, the stability of the pigment-containing vinyl polymer particle aqueous dispersion was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1.

<Evaluation criteria>
A: Viscosity, average particle diameter and PDI are all less than ± 5% of the values before storage.
B: Viscosity, average particle diameter and PDI are within ± 5 to 10% of the values before storage.
C: Viscosity, average particle diameter and PDI are ± 10% or more of the values before storage.

(Discharge accuracy evaluation)
The produced pigment ink composition was sealed in a PET container and stored in a constant temperature bath at 70 ° C. for 5 days. As an inkjet recording apparatus, a DMP-2831 printer manufactured by Fujifilm Dimatix was used, and a 10 cm line was printed at an ink droplet amount of 2 pL, an ejection frequency of 20 kHz, a nozzle array row direction × transport direction 16 × 1200 dots / 25.4 mm. As a recording medium, Fuji Photo Film Co., Ltd. picture-finishing photo finishing Pro was used. The distance between lines at a site 5 cm from the droplet ejection start portion of the print sample was measured with a dot analyzer EDA-6000 manufactured by Oji Scientific Instruments, its standard deviation was calculated, and the ejection direction accuracy was evaluated. The evaluation results are shown in Table 1.

<Evaluation criteria>
A: Standard deviation is less than 3 μm B: Standard deviation is 3 μm or more and less than 4 μm C ... Standard deviation is 4 μm or more and less than 5 μm D ... Standard deviation is 5 μm or more

(Light resistance)
Using the prepared pigment ink composition as an inkjet recording apparatus, a PX-V630 manufactured by Seiko Epson Corporation was used to print a yellow single-color solid image of Dmax. As a recording medium, Fuji Photo Film Co., Ltd. picture-finishing photo finishing Pro was used. A yellow single-color solid image part was prepared so that OD = 1.0, and a xenon fading test was performed for each. The OD at 14 days after exposure to xenon was measured and evaluated according to the following criteria. The evaluation results are shown in Table 1.

<Evaluation criteria>
A: Decrease in OD is less than 30%.
B: OD decrease is 30% to less than 50%.
C: OD decrease is 50% or more.

(Abrasion resistance)
Similar to the above-described ejection stability evaluation, an inkjet apparatus provided with a prototype print head of 600 dpi and 256 nozzles was prepared as an inkjet recording apparatus. A water-based ink obtained by storing the water-based ink for ink-jet recording obtained above in a 70 ° C. environment for 5 days was loaded into this, and a yellow solid color image was printed on FX-L paper (Fuji Xerox Co., Ltd.). Printed. It was wound around a paperweight (mass: 470 g, size: 15 mm × 30 mm × 120 mm) with the solid image marking screen facing outward, and rubbed 3 times on another blank FX-L paper (corresponding to a load of 260 kg / m ² ). The marking screen after rubbing was visually observed, collated with a predetermined limit sample, and visual sensory evaluation was performed according to the following evaluation criteria. The evaluation results are shown in Table 1.

<Evaluation criteria>
AA ... It was not scratched.
A: Slightly (two or less places) scratches.
B: Although 3 to 10 scratches were found, it was a practically acceptable level.
C ... 11 or more scratches were present, and there was a problem in practical use.

Claims (8)

(I) a mixing step of mixing a material containing the following A, B, C and D in the following ratio with respect to the total amount of A, B, C and D to obtain a pigment solution;
A: At least one selected from the group consisting of azo pigments represented by the following general formula (1), tautomers, salts and hydrates thereof : 5 to 25% by mass
B: Water-insoluble polymer comprising a hydrophobic structural unit and a hydrophilic structural unit : 1 to 15% by mass
C: Surfactant : 1 to 15% by mass
D: at least one acid solvent selected from the group consisting of acids, mixed acids , and acids or mixed solvents of mixed acids and organic solvents : 50 to 82.6% by mass
(Ii) An aqueous solvent that is compatible with the pigment solution obtained in the mixing step and the acid solvent (D) under the conditions of pH 8 to 13 but is a poor solvent for the azo pigment. And a precipitation / dispersion step of precipitating fine particles of the azo pigment to obtain a pigment dispersion,
A method for producing a water-based pigment dispersion, comprising:
General formula (1):

(In General Formula (1), Z represents a 5-6 membered heterocyclic ring, Y < ₁ >, Y < ₂ >, R < ₁₁ >, R < ₁₂ > represents a hydrogen atom or a substituent each independently, G < ₁ >, G < ₂ > is Each independently represents a hydrogen atom, an alkyl group, an aralkyl group, an alkenyl group, an alkynyl group, an aryl group or a heterocyclic group, and W ₁ and W ₂ each independently represent an alkoxy group, an amino group, an alkyl group or an aryl group. ) The water-insoluble polymer (B) is a polymer containing a structural unit derived from at least one of acrylic acid and methacrylic acid , and has an acid value of 45 mgKOH / g to 100 mgKOH / g. A method for producing a water-based pigment dispersion.   The method for producing an aqueous pigment dispersion according to claim 1 or 2, wherein the surfactant (C) is dissolved in the pigment solution.   The method for producing an aqueous pigment dispersion according to any one of claims 1 to 3, further comprising a step of mixing water in the mixing step.   The acid solvent (D) is an acid or a mixed solvent of a mixed acid and an organic solvent, and the amount of the organic solvent is 30 to 90% by mass with respect to the total amount of the acid solvent. The manufacturing method of the water-system pigment dispersion as described in any one of -4.   The aqueous pigment dispersion according to claim 1, wherein the acid solvent (D) is an acid or a mixed solvent of a mixed acid and an organic solvent, and the mixing step further includes a step of mixing water. Body manufacturing method. The water-based pigment dispersion manufactured by the manufacturing method as described in any one of Claims 1-6 . A water-based ink for ink jet recording comprising the water-based pigment dispersion according to claim 7 .