JP2014084392A - Azo compound, ink composition, recording method and colored body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dye excellent in especially moisture resistance, and bronze resistance, light resistance, (ozone)gas resistance and storage stability in a solution, having high print density and low chroma, having high quality black color tone with low color rendering property when recorded on a paper exclusively used for inkjet, to provide an ink composition containing the dye, especially an ink composition for inkjet recording.SOLUTION: There is provided an azo compound represented by the formula (1), or a tautomer thereof or their salts. In the formula (1), X represents a phenyl group may have a substituent, Rto Rrepresent each independently a hydrogen atom, a halogen atom, a cyano group, a carboxyl group, a sulfo group, a sulfamoyl group, a (C1 to C4) alkyl group, a (C1 to C4) alkoxy group and the like, and n represents an integer of 0 or 1).

Description

  The present invention relates to a novel azo compound or a tautomer thereof, or a salt thereof, an ink composition containing these, and a colored product colored by them.

  A recording method using an ink jet printer, that is, an ink jet recording method is one of representative methods among various color recording methods. The ink jet recording method performs recording by generating droplets of ink and attaching them to various recording materials (paper, film, fabric, etc.). This method is quiet because it does not generate sound because the recording head and the recording material are not in direct contact. In addition, due to the feature of being easy to downsize and increase the speed, it has been spreading rapidly in recent years and is expected to grow greatly in the future. Conventionally, water-based inks in which water-soluble pigments are dissolved in an aqueous medium have been used as fountain pens, felt-tip pens, and ink for ink jet recording. In general, a water-soluble organic solvent is added to these water-based inks in order to prevent clogging of the ink at the pen tip or the ink discharge nozzle. With these inks, it is possible to provide a recording image with sufficient density, no clogging of the pen tip and nozzles, good drying on the recording material, less bleeding, and storage stability. It is required to be excellent. In addition, the water-soluble dye used is required to have a particularly high solubility in water and a high solubility in a water-soluble organic solvent added to the ink. Further, the formed image is required to have image fastness such as water resistance, light resistance, gas resistance and moisture resistance.

  Among these, the gas resistance refers to the resistance to a phenomenon in which ozone gas having an oxidizing action existing in the air acts on the dye on the recording paper or in the recording paper to discolor the recorded image. . In addition to ozone gas, examples of the oxidizing gas having this kind of action include NOx and SOx. However, among these oxidizing gases, ozone gas is regarded as a main causative substance that promotes the discoloration phenomenon of ink jet recorded images, and particularly, ozone gas resistance is regarded as important. An ink receiving layer is provided on the surface of the exclusive inkjet paper capable of obtaining photographic image quality in order to expedite ink drying and to reduce bleeding at high image quality. In many cases, the ink receiving layer is made of a material such as a porous white inorganic material. On such a recording paper, the discoloration due to ozone gas or the like is noticeable. Since this discoloration phenomenon due to the oxidizing gas is characteristic of an ink jet recording image, improvement of gas resistance, particularly ozone gas resistance, is one of the most important issues in ink jet recording.

  Moisture resistance refers to resistance to a phenomenon in which a dye that forms an image after recording is discolored due to excessive moisture mainly in the surrounding environment contained in the atmosphere or oozes out of the image. In recent years, ink-jet recordings exhibited in various environments are regarded as important issues, but those that sufficiently satisfy market demands have not yet been developed.

  The bronze phenomenon refers to a phenomenon in which the dye becomes flakes on the surface of the recording material due to the association of the dyes or poor ink absorption. When this phenomenon occurs, the gloss, print quality, and print density are all inferior. In particular, when a metal phthalocyanine dye is used as a pigment, it often appears as a `` red floating phenomenon '' in a portion printed at a high density, and the color balance of the entire image becomes uneven and the quality is deteriorated. A pigment that does not cause bronzing is desired. In recent years, glossy paper is often used as a recording medium having a texture close to photographic tone. However, when a bronze phenomenon occurs, glossiness on the surface of the recorded material varies, and the texture of the image is significantly impaired. From this point of view, there is a strong demand for pigments that do not cause bronzing.

  In the future, in order to expand the field of use of ink jet recording, further improvement in light resistance, gas resistance, moisture resistance, water resistance, bronze resistance and the like is strongly demanded for ink jet recorded images. In addition to this, a black image is required to have a low color rendering property. A phenomenon in which the hue appears to change depending on the type of the light source is referred to as color rendering, but generally this phenomenon is likely to occur in black dyed matter or recorded matter. In the field of dyeing and processing, it is common to use a compound having absorption at a long wavelength as a method for improving color rendering properties. For example, Patent Documents 7 and 8 and Non-Patent Document 1 disclose these methods.

  Various hue inks are prepared from various pigments, of which black ink is an important ink used for both monocolor and full color images. Many pigments for these black inks have been proposed to date, but they have not yet provided a pigment that sufficiently satisfies the demands of the market. Many of the proposed dyes are azo dyes, of which C.I. I. Disazo dyes such as Food Black 2 have problems such as poor water resistance and moisture resistance, insufficient light resistance and gas resistance, and high color rendering. The polyazo dyes with extended conjugated systems generally have problems such as low water solubility, a bronzing phenomenon in which the recorded image has a partially metallic luster, and insufficient light resistance and gas resistance. Similarly, many azo metal-containing dyes that have been proposed have good light resistance, but they contain metal ions, which are undesirable for safety and environmental issues for living organisms, and have extremely high gas resistance. There are problems such as weakness.

  As a black compound (black pigment) for ink jet recording improved with respect to gas resistance, which has become the most important issue in recent years, for example, the compounds described in Patent Document 1 can be mentioned. Although the gas resistance of these compounds has been improved, they do not fully meet market demands. Black azo compounds are disclosed in Patent Documents 2 to 15 and the like. Patent Document 2 discloses a known compound that is widely used for inkjet. Patent Document 3 discloses an azo compound having a naphthalene skeleton substituted with a hydroxy group, an amino group, and a sulfo group, which is one of the characteristics of the black pigment of the present invention. No analogs of the compounds are disclosed. Patent Documents 4 and 15 disclose that a water-soluble black compound having a structure similar to that of the compound of the present invention is used for inkjet recording. Patent Document 6 discloses that a tetrakisazo compound and a water-soluble black compound are used for inkjet recording.

International Publication No. 2005/054374 Japanese Patent Application Laid-Open No. 07-118585 International Publication No. 2007/077931 International Publication No. 2009/069279 JP 2008-169374 A Japanese Patent No. 4502274 Japanese Patent No. 4679403 Japanese Patent No. 4764629 International Publication No. 2006/132327 International Publication No. 2007/032377 International Publication No. 2007/077931 International Publication No. 2007/138925 JP-A-2005-222111 Japanese Patent No. 4632770 Patent No. 4641194 Japanese Patent No. 4641768 Processing Technology Vol. 31, No. 9, 1996, 599-602

  The present invention is particularly excellent in moisture resistance when recorded on inkjet paper, and also excellent in bronze resistance, light resistance, (ozone) gas resistance, storage stability in aqueous solution, high print density, and color. An object of the present invention is to provide a pigment having a high-quality black hue with a low degree of color rendering and a color rendering property, and an ink composition containing the pigment, particularly an ink composition for inkjet recording.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a specific azo compound can solve the above-mentioned problems, and have completed the present invention.

［式（１）中、
Ｘは置換基を有しても良いフェニル基を表す。
Ｒ^１乃至Ｒ^４はそれぞれ独立して、水素原子；ハロゲン原子；シアノ基；カルボキシ基；スルホ基；スルファモイル基；（Ｃ１〜Ｃ４）アルキル基；（Ｃ１〜Ｃ４）アルコキシ基；ヒドロキシ基若しくは（Ｃ１〜Ｃ４）アルコキシ基で置換されてもよい（Ｃ１〜Ｃ４）アルキル基；ヒドロキシ基、（Ｃ１〜Ｃ４）アルコキシ基、スルホ基又はカルボキシ基で置換されてもよい（Ｃ１〜Ｃ４）アルコキシ基；Ｎ−アルキルアミノスルホニル基；Ｎ−フェニルアミノスルホニル基；ホスホ基；ニトロ基；アシル基；ウレイド基；（Ｃ１〜Ｃ４）アルコキシ基、スルホ基又はカルボキシ基で置換されてもよいアシルアミノ基を表す。
ｎは０又は１の整数を表す。］
２）
上記式（１）において、
Ｒ^１がカルボキシ基、スルホ基、又は（Ｃ１〜Ｃ４）アルコキシ基、
Ｒ^２が水素原子、又はスルホ基、
Ｒ^３及びＲ^４のいずれか一つが水素原子であり、もう一つがスルホ基である上記１）に記載のアゾ化合物若しくはその互変異性体、又はそれらの塩、
３）
上記式（１）において、
Ｘがスルホ基、カルボキシ基、スルホ基又はカルボキシ基で置換された（Ｃ１〜Ｃ４）アルキル基、無置換（Ｃ１〜Ｃ４）アルキル基、スルホ基又はカルボキシ基で置換された（Ｃ１〜Ｃ４）アルコキシ基、無置換（Ｃ１〜Ｃ４）アルコキシ基、スルホ基又はカルボキシ基で置換された（Ｃ１〜Ｃ４）チオアルキル基、ハロゲン原子、ニトロ基、ヒドロキシ基、アミノ基、アルキルアミノ基、フェニルアミノ基、アシルアミノ基、アセチルオキシ基、ｐ−トルエンスルホニルオキシ基、スルホ基又はカルボキシ基で置換されたアルキルスルホニル基、無置換アルキルスルホニル基、スルホ基又はカルボキシ基で置換されたフェニルスルホニル基、無置換フェニルスルホニル基、又はスルファモイル基で置換されたフェニル基である上記１）又は２）に記載のアゾ化合物若しくはその互変異性体、又はそれらの塩、
４）
上記式（１）において、
Ｒ^１がカルボキシ基、又はスルホ基、
Ｒ^２が水素原子、
Ｒ^３及びＲ^４のいずれか一つが水素原子であり、もう一つがスルホ基、
Ｘがスルホ基、カルボキシ基、無置換（Ｃ１〜Ｃ４）アルキル基、スルホ（Ｃ１〜Ｃ４）アルコキシ基、無置換（Ｃ１〜Ｃ４）アルコキシ基、スルホ（Ｃ１〜Ｃ４）チオアルキル基、ハロゲン原子、アミノ基、ニトロ基、又はアセチルアミノ基で置換されたフェニル基であり、
ｎが１である上記１）乃至３）のいずれか一項に記載のアゾ化合物若しくはその互変異性体、又はそれらの塩、
５）
上記式（１）において、
Ｘが少なくとも一つの水溶性置換基を有するフェニル基である上記１）乃至４）のいずれか一項に記載のアゾ化合物若しくはその互変異性体、又はそれらの塩、
６）
上記１）乃至５）のいずれか一項に記載のアゾ化合物若しくはその互変異性体、又はそれらの塩を、色素として少なくとも１種類含有する水性インク組成物、
７）
水溶性有機溶剤をさらに含有する上記７）に記載の水性インク組成物、
８）
上記６）又は７）に記載のインク組成物をインクとして用い、該インクのインク滴を記録信号に応じて吐出させて被記録材に記録を行うインクジェット記録方法、
９）
被記録材が情報伝達用シートである上記８）に記載のインクジェット記録方法、
１０）
情報伝達用シートが多孔性白色無機物を含有するインク受容層を有するシ−トである上記９）に記載のインクジェット記録方法、
１１）
上記６）又は７）に記載のインク組成物を含む容器を装填したインクジェットプリンタ、
１２）
ａ）上記１）乃至５）のいずれか一項に記載のアゾ化合物若しくはその互変異性体、又はそれらの塩、
ｂ）上記６）又は７）に記載の水性インク組成物、又は、
ｃ）上記８）に記載のインクジェット記録方法、の３者のいずれかによって着色された着色体、に関する。 That is, the present invention
1)
An azo compound represented by the following formula (1) or a tautomer thereof, or a salt thereof;

[In Formula (1),
X represents a phenyl group which may have a substituent.
R ^{1 to} R ⁴ are each independently a hydrogen atom; a halogen atom; a cyano group; a carboxy group; a sulfo group; a sulfamoyl group; a (C1-C4) alkyl group; a (C1-C4) alkoxy group; a hydroxy group or (C1 -C4) (C1-C4) alkyl group optionally substituted with an alkoxy group; (C1-C4) alkoxy group optionally substituted with a hydroxy group, (C1-C4) alkoxy group, a sulfo group or a carboxy group; N -Alkylaminosulfonyl group; N-phenylaminosulfonyl group; phospho group; nitro group; acyl group; ureido group; (C1-C4) an acylamino group which may be substituted with an alkoxy group, a sulfo group or a carboxy group.
n represents an integer of 0 or 1. ]
2)
In the above formula (1),
R ¹ is a carboxy group, a sulfo group, or a (C1-C4) alkoxy group,
R ² is a hydrogen atom or a sulfo group,
Any one of R ³ and R ⁴ is a hydrogen atom, and the other is a sulfo group, the azo compound or a tautomer thereof according to 1), or a salt thereof,
3)
In the above formula (1),
X is a (C1-C4) alkyl group substituted with a sulfo group, a carboxy group, a sulfo group or a carboxy group, an unsubstituted (C1-C4) alkyl group, a (C1-C4) alkoxy substituted with a sulfo group or a carboxy group Group, unsubstituted (C1-C4) alkoxy group, (C1-C4) thioalkyl group substituted by sulfo group or carboxy group, halogen atom, nitro group, hydroxy group, amino group, alkylamino group, phenylamino group, acylamino Group, acetyloxy group, p-toluenesulfonyloxy group, alkylsulfonyl group substituted with sulfo group or carboxy group, unsubstituted alkylsulfonyl group, phenylsulfonyl group substituted with sulfo group or carboxy group, unsubstituted phenylsulfonyl group 1) or a phenyl group substituted with a sulfamoyl group Azo compound or a tautomer thereof according to 2), or a salt thereof,
4)
In the above formula (1),
R ¹ is a carboxy group or a sulfo group,
R ² is a hydrogen atom,
Any one of R ³ and R ⁴ is a hydrogen atom, the other is a sulfo group,
X is a sulfo group, a carboxy group, an unsubstituted (C1-C4) alkyl group, a sulfo (C1-C4) alkoxy group, an unsubstituted (C1-C4) alkoxy group, a sulfo (C1-C4) thioalkyl group, a halogen atom, amino A phenyl group substituted with a group, a nitro group, or an acetylamino group,
The azo compound or tautomer thereof according to any one of 1) to 3), wherein n is 1, or a salt thereof,
5)
In the above formula (1),
The azo compound or a tautomer thereof according to any one of 1) to 4), or a salt thereof, wherein X is a phenyl group having at least one water-soluble substituent,
6)
An aqueous ink composition containing at least one kind of the azo compound according to any one of 1) to 5) or a tautomer thereof, or a salt thereof;
7)
The water-based ink composition as described in 7) above, further comprising a water-soluble organic solvent,
8)
An ink jet recording method for recording on a recording material by using the ink composition according to 6) or 7) as an ink, and discharging ink droplets of the ink according to a recording signal;
9)
The inkjet recording method according to 8) above, wherein the recording material is an information transmission sheet,
10)
The ink jet recording method according to 9) above, wherein the information transmission sheet is a sheet having an ink receiving layer containing a porous white inorganic substance,
11)
An ink jet printer loaded with a container containing the ink composition according to 6) or 7),
12)
a) The azo compound according to any one of 1) to 5) or a tautomer thereof, or a salt thereof,
b) The water-based ink composition as described in 6) or 7) above, or
c) A colored body colored by any one of the three methods described in 8) above.

  The azo compound of the present invention or a salt thereof, and an ink composition containing the azo compound are suitably used as an ink for ink jet recording, and are particularly excellent in moisture resistance and have a very high printing density when recorded on ink jet dedicated paper. The ink composition containing the azo compound of the present invention has high blackness, low saturation, high-quality black hue, and excellent light resistance, (ozone) gas resistance, and bronze resistance. It is extremely useful as a black ink for recording.

Hereinafter, the present invention will be described in detail.
For the sake of convenience, in the present specification, the “azo compound of the present invention”, including all of the “azo compound of the present invention or a tautomer thereof, or a salt thereof”, will be simply described below. Here, examples of the tautomer include a structure of the following formula (2).

In the above formula (1), R ^{1 to} R ⁴ each independently represent a hydrogen atom; a halogen atom; a cyano group; a carboxy group; a sulfo group; a sulfamoyl group; a (C1-C4) alkyl group; A group; a hydroxy group or a (C1-C4) alkyl group optionally substituted with a (C1-C4) alkoxy group; a hydroxy group, a (C1-C4) alkoxy group, a sulfo group or a carboxy group. (C1-C4) alkoxy group; N-alkylaminosulfonyl group; N-phenylaminosulfonyl group; phospho group; nitro group; acyl group; ureido group; (C1-C4) substituted with alkoxy group, sulfo group or carboxy group Represents an acylamino group which may be substituted.

Examples of the halogen atom in R ^{1 to} R ⁴ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. A fluorine atom, a chlorine atom, and a bromine atom are preferable, and a chlorine atom is more preferable.

In the above formula (1), examples of the (C1 to C4) alkyl group in R ^{1 to} R ⁴ include a linear or branched unsubstituted group, and a linear group is preferable. Specific examples thereof include, for example, a linear group such as a methyl group, an ethyl group, an n-propyl group, and an n-butyl group; a branched chain such as an isopropyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group; Is mentioned. Preferable specific examples include a methyl group and an n-propyl group, and a methyl group is particularly preferable.

In the above formula (1), examples of the (C1 to C4) alkoxy group in R ^{1 to} R ⁴ include those in which alkyl is linear or branched, and linear is preferable. Specific examples thereof include, for example, straight chain such as methoxy group, ethoxy group, n-propoxy group, and n-butoxy group; branched chain such as isopropoxy group, isobutoxy group, sec-butoxy group, and tert-butoxy group; Etc. Preferable specific examples include a methoxy group, an ethoxy group, and an n-propoxy group, and a methoxy group is particularly preferable.

In the above formula (1), the (C1 to C4) alkyl group which may be substituted with a hydroxy group or a (C1 to C4) alkoxy group in R ^{1 to} R ⁴ is any of the above (C1 to C4) alkyl groups. In which the carbon atom is substituted with a hydroxy group or a (C1-C4) alkoxy group. The substitution position of the hydroxy group or (C1-C4) alkoxy group is not particularly limited, but substitution at the end of the alkyl group is preferred, and the number of substitutions is 1 or 2, preferably 1. Examples of the (C1 to C4) alkoxy group include the (C1 to C4) alkoxy group in the above R ^{1 to} R ⁴ and the same examples including specific examples, preferable ones, and particularly preferable ones. Specific examples of the (C1-C4) alkyl group which may be substituted with a hydroxy group or a (C1-C4) alkoxy group include a hydroxymethyl group, a 2-hydroxyethyl group, a 3-hydroxy-n-propyl group, 4- Hydroxy-n-butyl group, methoxymethyl group, 2-methoxyethyl group, 3-methoxy-n-propyl group, 4-methoxy-n-butyl group, ethoxymethyl group, 2-ethoxyethyl group, 3-ethoxy-n -Propyl group, 4-ethoxy-n-butyl group, n-propoxymethyl group, 2- (n-propoxy) ethyl group, 3- (n-propoxy) -n-propyl group, 4- (n-propoxy)- n-butyl group, (n-butoxy) methyl group, 2- (n-butoxy) ethyl group, 3- (n-butoxy) -n-propyl group, 4- (n-butoxy) -n-buty Group, and the like.

In the above formula (1), the hydroxy group in R ^{1 to} R ⁴ , the (C1 to C4) alkoxy group, the sulfo group, or the carboxy group (C1 to C4) that may be substituted with the alkoxy group includes the above (C1 to C4). ) A carbon atom of an alkoxy group is substituted with a hydroxy group, a (C1-C4) alkoxy group, a sulfo group or a carboxy group. The substitution position of the hydroxy group, (C1 to C4) alkoxy group, sulfo group or carboxy group is not particularly limited, but it is preferably substituted at the terminal of the alkyl group, and the substitution number is 1 or 2, preferably 1. Examples of the (C1 to C4) alkoxy group as a substituent include the above (C1 to C4) alkoxy groups and specific examples, preferable ones, and particularly preferable ones. Specific examples of the (C1-C4) alkoxy group which may be substituted with a hydroxy group, a (C1-C4) alkoxy group, a sulfo group or a carboxy group include a hydroxymethoxy group, a hydroxyethoxy group, a hydroxy-n-propoxy group, Substituted with a hydroxy group such as hydroxy-n-butoxy group; methoxymethoxy group, methoxyethoxy group, methoxy-n-propoxy group, methoxy-n-butoxy group, ethoxymethoxy group, ethoxyethoxy group, ethoxy-n- Propoxy group, ethoxy-n-butoxy group, (n-propoxy) methoxy group, (n-propoxy) ethoxy group, (n-propoxy) -n-propoxy group, (n-propoxy) -n-butoxy group, (n -Butoxy) methoxy group, (n-butoxy) ethoxy group, (n-butoxy) -n-pro Xoxy group, (n-butoxy) -n-butoxy group, isopropoxymethoxy group, isopropoxyethoxy group, isopropoxy-n-propoxy group, isopropoxy-n-butoxy group, (tert-butoxy) methoxy group, (tert Substituted with (C1-C4) alkoxy groups such as (butoxy) ethoxy group, (tert-butoxy) -n-propoxy group, (tert-butoxy) -n-butoxy group; sulfomethoxy group, sulfoethoxy group, Substituted with a sulfo group such as sulfo-n-propoxy group, sulfo-n-butoxy group; substituted with a carboxy group such as carboxymethoxy group, carboxyethoxy group, carboxy-n-propoxy group, carboxy-n-butoxy group , Sulfo-n-propoxy group, sulfo-n-butoxy group Carboxy -n- propoxy group, a carboxy -n- butoxy group, a sulfo -n- propoxy group, a sulfo -n- butoxy group are more preferable.

In the above formula (1), as the N-alkylaminosulfonyl group in R ^{1 to} R ⁴ , alkyl is a (C1-C8) alkyl group, preferably a (C1-C6) alkyl group, more preferably (C1-C4). The thing which is an alkyl group is mentioned, The same thing is mentioned including the said (C1-C4) alkyl group, a specific example, a preferable thing, and a more preferable thing. Specific examples of the N-alkylaminosulfonyl group include N-methylaminosulfonyl group, N-ethylaminosulfonyl group, N- (n-propoxy) aminosulfonyl group, N- (n-butyl) aminosulfonyl group, N- And isopropoxyaminosulfonyl group, N- (tert-butyl) aminosulfonyl group, and the like. N-methylaminosulfonyl group, N-ethylaminosulfonyl group, N- (n-propoxy) aminosulfonyl group, N- (n -Butyl) aminosulfonyl group is preferable, and N-methylaminosulfonyl group and N-ethylaminosulfonyl group are more preferable.

In the above formula (1), examples of the acyl group in R ^{1 to} R ⁴ include an acetyl group, a benzoyl group, an aldehyde group, and an amide group.

In the above formula (1), the acylamino group which may be substituted with the (C1-C4) alkoxy group, sulfo group or carboxy group in R ^{1 to} R ⁴ is a (C1-C4) alkoxy group on the carbon atom of the acyl group. A group, a sulfo group or a carboxy group is substituted. The number of substitutions is 1 or 2, preferably 1. Examples of the (C1 to C4) alkoxy group include the above (C1 to C4) alkoxy groups, specific examples, preferable ones, and more preferable ones. (C1-C4) Specific examples of the acylamino group which may be substituted with an alkoxy group, a sulfo group or a carboxy group include a 2-methoxybenzoyl group, a 3-methoxybenzoyl group, a 4-methoxybenzoyl group and a 2-ethoxybenzoyl group. 3-ethoxybenzoyl group, 4-ethoxybenzoyl group, 2- (n-propoxy) benzoyl group, 3- (n-propoxy) benzoyl group, 4- (n-propoxy) benzoyl group, 2- (n-butoxy) Benzoyl group, 3- (n-butoxy) benzoyl group, 4- (n-butoxy) benzoyl group, 2-isopropoxybenzoyl group, 3-isopropoxybenzoyl group, 4-isopropoxybenzoyl group, 2- (tert-butoxy) ) Benzoyl group, 3- (tert-butoxy) benzoyl group, 4- (tert-butoxy) ) Benzoyl group, 2,6-dimethoxybenzoyl group, 2,6-diisopropoxybenzoyl group, 2-sulfobenzoyl group, 3-sulfobenzoyl group, 4-sulfobenzoyl group, 2,4-disulfobenzoyl group, 2 , 5-Disulfobenzoyl group, 2-carboxybenzoyl group, 3-carboxybenzoyl group, 4-carboxybenzoyl group, 3,5-dicarboxybenzoyl group, 2,5-dicarboxybenzoyl group, 2-carboxy-5- A sulfobenzoyl group etc. are mentioned, 2-sulfobenzoyl group, 4-sulfobenzoyl group, 2-carboxybenzoyl group, 4-carboxybenzoyl group is preferable.

R ¹ is preferably a halogen atom that is an electron-attracting substituent; a cyano group; a carboxy group; a sulfo group; a sulfamoyl group, or a (C1-C4) alkoxy group, and further a carboxy group, a sulfo group, or The case where it is a (C1-C4) alkoxy group is more preferable. Here, as a (C1-C4) alkoxy group, it is as above-mentioned including a preferable thing. In addition, a carboxy group and a sulfo group are more preferable, and a sulfo group is particularly preferable.
R ² is preferably a hydrogen atom or a halogen atom which is an electron-withdrawing substituent; a cyano group; a carboxy group; a sulfo group; a sulfamoyl group, more preferably a hydrogen atom or a sulfo group, Particularly preferred is an atom.
One of R ³ and R ⁴ is preferably a hydrogen atom and the other is a halogen atom which is an electron-withdrawing substituent; a cyano group; a carboxy group; a sulfo group; a sulfamoyl group. Further, it is more preferable that any one is a hydrogen atom and the other is a sulfo group, and it is particularly preferable that R ³ is a hydrogen atom and R ⁴ is a sulfo group.

  In the above formula (1), X represents a phenyl group which may have a substituent.

In X, the substituent which may be present is not particularly limited, but is a (C1-C4) alkyl group substituted with a sulfo group, a carboxy group, a sulfo group or a carboxy group, or an unsubstituted (C1-C4). ) (C1-C4) alkoxy group substituted by alkyl group, sulfo group or carboxy group, unsubstituted (C1-C4) alkoxy group, (C1-C4) thioalkyl group substituted by sulfo group or carboxy group, halogen atom , Nitro group, hydroxy group, amino group, alkylamino group, phenylamino group, acylamino group, acetyloxy group, p-toluenesulfonyloxy group, alkylsulfonyl group substituted with sulfo group or carboxy group, unsubstituted alkylsulfonyl group , Phenylsulfonyl group substituted by sulfo group or carboxy group, unsubstituted phenylsulfonyl group Or a sulfamoyl group, more preferably a sulfo group, a carboxy group, an unsubstituted (C1-C4) alkyl group, a sulfo (C1-C4) alkoxy group, an unsubstituted (C1-C4) alkoxy group, a sulfo (C1 To C4) a thioalkyl group, a halogen atom, an amino group, a nitro group, or an acetylamino group, particularly preferably a sulfo group, a carboxy group, or a halogen atom.
In addition, when X has a water-soluble substituent, the effect of the present invention can be more remarkably exhibited. In this case, the effect can be confirmed even if it has another substituent or not. Is done. Here, examples of the water-soluble substituent include a sulfo group and a carboxy group, and any of them is preferable.
Hereinafter, substituents that X may have will be described in more detail.

  In the above formula (1), X having a substituent is a sulfo group, a carboxy group, a sulfo group or a (C1-C4) alkyl group substituted with a carboxy group, an unsubstituted (C1-C4) alkyl group, a sulfo group. (C1-C4) alkoxy group substituted with a group or carboxy group, unsubstituted (C1-C4) alkoxy group, (C1-C4) thioalkyl group substituted with sulfo group or carboxy group, halogen atom, nitro group, hydroxy Group, amino group, alkylamino group, phenylamino group, acylamino group, acetyloxy group, p-toluenesulfonyloxy group, alkylsulfonyl group substituted with sulfo group or carboxy group, unsubstituted alkylsulfonyl group, sulfo group or carboxy group Group substituted phenylsulfonyl group, unsubstituted phenylsulfonyl group, or sulfamoyl group There is a phenyl group substituted is not particularly substituted position limits, number of substituents 1 to 3, preferably 1 or 2.

Examples of the (C1 to C4) alkyl group substituted with a sulfo group or a carboxy group in X include those in which a carbon atom of the (C1 to C4) alkyl group is substituted with a sulfo group or carboxy. Examples of the (C1 to C4) alkyl group include the (C1 to C4) alkyl group in the above R ^{1 to} R ⁴ and the same examples including specific examples, preferable ones, and more preferable ones. The number of substitutions is 1 or 2, preferably 1. Specific examples of the (C1-C4) alkyl group substituted with a sulfo group or a carboxy group include a sulfomethyl group, a 2-sulfoethyl group, a 3-sulfo-n-propyl group, a 4-sulfo-n-butyl group, and carboxymethyl. Group, 2-carboxyethyl group, 3-carboxy-n-propyl group, 4-carboxy-n-butyl group and the like, and sulfomethyl group or carboxymethyl group is preferable.

Examples of the unsubstituted (C1 to C4) alkyl group in X include the same examples as the (C1 to C4) alkyl group in R ^{1 to} R ⁴ , including specific examples, preferred ones, and more preferred ones.

The (C1-C4) alkoxy group substituted with a sulfo group or a carboxy group in X includes preferred and more preferred hydroxy groups in the above R ^{1 to} R ⁴ , (C1-C4) alkoxy groups, sulfo The thing similar to the (C1-C4) alkoxy group which may be substituted by the sulfo group or carboxy group in the (C1-C4) alkoxy group which may be substituted by a group or a carboxy group is mentioned.

Examples of the unsubstituted (C1 to C4) alkoxy group in X include the same as the (C1 to C4) alkoxy group in the above R ^{1 to} R ⁴ .

  Examples of the (C1-C4) thioalkyl group substituted with a sulfo group or a carboxy group in X include those in which a sulfo group or a carboxy group is substituted on any carbon atom of the (C1-C4) thioalkyl group. Although the substitution position of the sulfo group or carboxy group is not particularly limited, it is preferably substituted at the end of the thioalkyl group, and the substitution number is 1 or 2, preferably 1. Specific examples of the (C1-C4) thioalkyl group substituted with a sulfo group or a carboxy group include a sulfomethylthio group, a 2-sulfoethylthio group, a 3-sulfo-n-propylthio group, and a 4-sulfo-n-butylthio group. Carboxymethylthio group, 2-carboxyethylthio group, 3-carboxy-n-propylthio group, 4-carboxy-n-butylthio group, etc., 3-sulfo-n-propylthio group, 4-sulfo-n-butylthio Group, 3-carboxy-n-propylthio group and 4-carboxy-n-butylthio group are preferable, and 3-sulfo-n-propylthio group and 4-sulfo-n-butylthio group are more preferable.

  Examples of the halogen atom in X include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. A fluorine atom, a chlorine atom, and a bromine atom are preferable, and a chlorine atom is more preferable.

As the alkylamino group in X, alkyl is a (C1-C8) alkyl group,
Preferable examples include (C1 to C4) alkyl groups, and specific examples, preferable examples, and more preferable examples include the same as (C1 to C4) alkyl groups in R ^{1 to} R ⁴ above. The number of substitution is 1 or 2. Specific examples of the alkylamino group include methylamino, ethylamino, n-propylamino, n-butylamino, methylethylamino, dimethylamino, diethylamino, di-n-propylamino, di-n-butylamino, methyl ( n-butyl) amino and the like.

Examples of the acylamino group in X include those in which the acyl group in R ^{1 to} R ⁴ is substituted with an amino group. Specific examples of the acylamino group include an acetylamino group, a benzoylamino group, and an amide group, and an acetylamino group is preferable.

  As the alkylsulfonyl group substituted with a sulfo group or a carboxy group in X, alkyl is a (C1-C8) alkyl group, preferably a (C1-C4) alkyl group, and the alkyl carbon atom is a sulfo group or a carboxy group. Although the substitution position is not particularly limited, the terminal of the alkyl is preferable, and the number of substitution is 1 or 2, preferably 1. Examples of the alkyl group include straight-chain, branched-chain, and cyclic groups, and straight-chain groups are preferred. Specific examples of the (C1-C4) alkylsulfonyl group substituted with a sulfo group or a carboxy group include a sulfomethylsulfonyl group, a 2-sulfoethylsulfonyl group, a 3-sulfo (n-propyl) sulfonyl group, and a 4-sulfo ( n-butyl) sulfonyl group, carboxymethylsulfonyl group, 2-carboxyethylsulfonyl group, 3-carboxy (n-propyl) sulfonyl group, 4-carboxy (n-butyl) sulfonyl group and the like, and 2-sulfoethylsulfonyl Group, 3-sulfo (n-propyl) sulfonyl group, 2-carboxyethylsulfonyl group, 3-carboxy (n-propyl) sulfonyl group are preferable, 3-sulfo (n-propyl) sulfonyl group, 2-carboxyethylsulfonyl group Is more preferable.

  Examples of the unsubstituted alkylsulfonyl group in X include those in which alkyl is a (C1-C8) alkyl group, preferably a (C1-C4) alkyl group. Examples of the alkyl group include a straight chain, a branched chain, and a cyclic group, and a straight chain is preferable. Specific examples of the unsubstituted alkylsulfonyl group include a methylsulfonyl group, an ethylsulfonyl group, an n-propylsulfonyl group, and an n-butylsulfonyl group.

  Examples of the phenylsulfonyl group substituted with a sulfo group or a carboxy group in X include those in which a sulfo group or a carboxy group is substituted on the carbon atom of phenyl, and the number of substitutions is 1 to 3, preferably 1 or 2. is there. Specific examples of the phenylsulfonyl group substituted with a sulfo group or a carboxy group include 2-sulfophenylsulfonyl group, 3-sulfophenylsulfonyl group, 4-sulfophenylsulfonyl group, 2,4-disulfophenylsulfonyl group, 2 , 5-disulfophenylsulfonyl group, 2-carboxyphenylsulfonyl group, 3-carboxyphenylsulfonyl group, 4-carboxyphenylsulfonyl group, 2,5-dicarboxyphenylsulfonyl group, 3,5-dicarboxyphenylsulfonyl group, A 2-carboxy-4-sulfophenylsulfonyl group, a 2-carboxy-5-sulfophenylsulfonyl group and the like can be mentioned, and a 2-carboxyphenylsulfonyl group is preferred.

  In the above formula (1), n represents 0 or 1, and the case of 1 is particularly preferable.

Specific examples of preferable combinations in the above formula (1) include the following combinations.
R ¹ is a sulfo group; a carboxy group;
R ² is a hydrogen atom,
Any one of R ³ and R ⁴ is a hydrogen atom, the other is a sulfo group,
A phenyl group in which X is a sulfo group, a carboxy group, or a halogen atom;
A combination where n is 1.

The azo compound of the present invention represented by the formula (1) can be synthesized, for example, by the following method. Moreover, the structural formula of the compound in each process shall be represented with the form of a free acid.
In the following formulas (3) to (5), X, R ^{1 to} R ⁴ , and n represent the same meaning as in the above formula (1).

A compound represented by X-NH ₂ is diazotized by a conventional method, and a compound represented by the following formula (3) that is generally commercially available is subjected to a coupling reaction by a conventional method. obtain.

  The compound of the above formula (4) is diazotized by a conventional method, and is subjected to a coupling reaction by a conventional method with a compound of the following formula (5) synthesized by the method described in JP-A-2006-76908, etc. ) Is obtained. However, the synthesis method is not particularly limited.

Although it does not specifically limit as a suitable specific example of the azo compound of this invention represented by the said Formula (1), The compound shown by the structural formula given to the following Table 1 thru | or 7 is mentioned.
In each table, functional groups such as sulfo group and carboxy group are described in the form of free acid for convenience.
Ac represents an acetyl group.

The diazotization of the compound represented by X—NH ₂ is carried out in a manner known per se, for example nitrite, for example nitrous acid, in an inorganic acid medium, for example at a temperature of −5 to 40 ° C., preferably 0 to 30 ° C. This is done using an alkali metal nitrite such as sodium. Coupling of the diazotized compound of the compound represented by X—NH ₂ with the compound of formula (3) is also carried out under conditions known per se. It is advantageous to carry out in water or an aqueous organic medium, for example at a temperature of -5 to 40 [deg.] C, preferably 0 to 30 [deg.] C and an acidic to neutral pH value, for example pH 1-7. Since the diazotization reaction liquid is acidic and the reaction system is further acidified by the progress of the coupling reaction, the pH value is adjusted to a preferable pH condition of the reaction liquid by adding a base. The same base as described above can be used. The compound represented by X—NH ₂ and the compound of the formula (3) are used in a substantially stoichiometric amount.

  The diazotization of the compound of formula (4) is carried out in a manner known per se, for example nitrite, such as sodium nitrite, in an inorganic acid medium, for example at a temperature of -5 to 40 ° C., preferably 0 to 30 ° C. It is carried out using an alkali metal nitrite salt. Coupling of the diazotized compound of the compound of formula (4) with the compound of formula (5) is also carried out under conditions known per se. It is advantageous to carry out the reaction in water or an aqueous organic medium, for example at a temperature of -5 to 40 ° C, preferably 0 to 30 ° C, and a weakly acidic to alkaline pH value, for example pH 4-12. Since the diazotization reaction liquid is acidic and the reaction system is further acidified by the progress of the coupling reaction, the pH value is adjusted to the preferred pH condition of the reaction liquid by adding a base. The same base as described above can be used. The compound of formula (4) and the compound of formula (5) are used in approximately stoichiometric amounts.

  The salt of the azo compound represented by the above formula (1) is a salt with an inorganic or organic cation. Among these, specific examples of inorganic salts include alkali metal salts, alkaline earth metal salts, and ammonium salts. Preferred inorganic salts are lithium, sodium, potassium, and ammonium salts. Examples of the organic cation salt include, but are not limited to, salts with quaternary ammonium ions represented by the following formula (6). In addition, the free acid of the azo compound of the present invention, its tautomer, and various salts thereof may be a mixture. For example, any combination such as a mixture of sodium salt and ammonium salt, a mixture of free acid and sodium salt, a mixture of lithium salt, sodium salt and ammonium salt may be used. The physical properties such as solubility may vary depending on the type of salt, and the physical properties that meet the purpose can be selected by selecting the type of salt as appropriate, or by changing the ratio when multiple salts are included. It is also possible to obtain a mixture having

In the formula (6), Z ¹ , Z ² , Z ³ and Z ⁴ each independently represent a group selected from the group consisting of a hydrogen atom, an unsubstituted alkyl group, a hydroxyalkyl group and a hydroxyalkoxyalkyl group, At least one is a group other than a hydrogen atom.
Specific examples of the alkyl group of Z ^{1 to} Z ⁴ in the formula (6) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. Specific examples of the hydroxyalkyl group include hydroxymethyl group, hydroxyethyl group, 3-hydroxypropyl group, 2-hydroxypropyl group, 4-hydroxybutyl group, 3-hydroxybutyl group, 2-hydroxybutyl group, etc. Examples of the hydroxyalkoxyalkyl group include hydroxyethoxymethyl group, 2-hydroxyethoxyethyl group, 3-hydroxyethoxypropyl group, 2-hydroxyethoxypropyl group, 4-hydroxyethoxy (C1-C4) alkyl group, Hydroxyethoxybutyl group, 3-hydroxyethoxybutyl Group, 2-hydroxyethoxy butyl group hydroxy (C1 -C4) alkoxy (C1 -C4) alkyl group. Among these hydroxyethoxy (C1 -C4) alkyl groups are preferred. Particularly preferred are hydrogen atom; methyl group, hydroxymethyl group, hydroxyethyl group, 3-hydroxypropyl group, 2-hydroxypropyl group, 4-hydroxybutyl group, 3-hydroxybutyl group, 2-hydroxybutyl group, etc. Hydroxy (C1-C4) alkyl group, hydroxyethoxymethyl group, 2-hydroxyethoxyethyl group, 3-hydroxyethoxypropyl group, 2-hydroxyethoxypropyl group, 4-hydroxyethoxybutyl group, 3-hydroxyethoxybutyl group, 2 -Hydroxyethoxy (C1-C4) alkyl groups such as hydroxyethoxybutyl group.

Specific examples of combinations of Z ¹ , Z ² , Z ³ , and Z ^{4 which} are preferable as the formula (6) are shown in Table 8 below.

As a method for synthesizing a desired salt of the azo compound represented by the formula (1) of the present invention, after completion of the final step in the synthesis reaction of the compound represented by the formula (1), a desired inorganic salt or organic Obtained by adding a mineral acid such as hydrochloric acid to the reaction solution and isolating the azo compound from the reaction solution in the form of a free acid. The free acid is washed with water, acidic water or an aqueous organic medium as necessary to remove impurities such as attached inorganic salts, and again in an aqueous medium (preferably in water). And a method of forming a salt by adding an organic base corresponding to the desired inorganic base or the above-described quaternary ammonium salt. By such a method, the salt of the target azo compound can be obtained in the form of a solution or a precipitated solid. Here, acidic water refers to water obtained by dissolving a mineral acid such as sulfuric acid or hydrochloric acid or an organic acid such as acetic acid in water. The aqueous organic medium refers to an admixture of water and an organic substance and / or an organic solvent that are miscible with water.
Examples of the water-miscible organic substance and organic solvent include water-soluble organic solvents described later.
Examples of inorganic salts used when the azo compound represented by the above formula (1) is used as a desired salt include halogen salts of alkali metals such as lithium chloride, sodium chloride and potassium chloride; lithium carbonate, sodium carbonate, carbonate Alkali metal carbonates such as potassium; Alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide; Halogen salts of ammonium ions such as ammonium chloride and ammonium bromide; Ammonium hydroxide (ammonia water) And the like.
Examples of organic cation salts include halogen salts of quaternary ammonium ions represented by the above formula (6) such as diethanolamine hydrochloride and triethanolamine hydrochloride.

  The ink composition of the present invention will be described. By making the azo compound represented by the above formula (1) of the present invention into an aqueous composition containing the compound, it is possible to dye a material made of cellulose. In addition, materials having carbamoyl groups can be dyed, and can be widely used for dyeing leather, fabrics, papers, and the like. On the other hand, a typical use of the compound of the present invention is an ink composition dissolved in a liquid medium, and is preferably used as an ink composition for inkjet recording.

  The reaction liquid containing the compound represented by the above formula (1), for example, the reaction liquid after the final step in the synthesis reaction of the compound represented by the above formula (1) is directly used for the production of the ink composition. I can do things. However, the reaction solution is dried, for example, spray-dried; the reaction solution is salted out by adding inorganic salts such as sodium chloride, potassium chloride, calcium chloride, sodium sulfate; the reaction solution is treated with hydrochloric acid, sulfuric acid The compound is isolated by a method of acid precipitation by adding a mineral acid such as nitric acid, or the like; A product can also be prepared. The azo compound of the present invention is preferably used after being isolated.

  The ink composition of the present invention is usually 0.1 to 20% by mass, preferably 1 to 10% by mass, more preferably 2 to 8% by mass, using the azo compound represented by the above formula (1) of the present invention as a pigment. % Water-based ink composition. The ink composition of the present invention is prepared using water as a medium, and may contain a water-soluble organic solvent and an ink preparation agent as necessary within a range that does not impair the effects of the present invention. The water-soluble organic solvent may have a function as a dye-dissolving agent, a drying inhibitor (wetting agent), a viscosity modifier, a penetration accelerator, a surface tension modifier, an antifoaming agent, etc., and the ink composition of the present invention It is preferable to contain them. Examples of the ink preparation agent include antiseptic / antifungal agents, pH adjusters, chelating reagents, rust preventives, water-soluble ultraviolet absorbers, water-soluble polymer compounds, dye solubilizers, antioxidants, and surfactants. These additives may be mentioned. In the ink composition of the present invention, the water-soluble organic solvent is 0 to 30% by mass, preferably 5 to 30% by mass, and the ink preparation agent is 0 to 15% by mass, preferably 0 to 7% by mass, based on the total mass. % May be contained respectively. The remainder other than the above is water. The pH of the ink composition is preferably pH 5 to 11 and more preferably pH 7 to 10 in terms of improving storage stability. Further, the surface tension of the ink composition is preferably 25 to 70 mN / m, and more preferably 25 to 60 mN / m. Furthermore, the viscosity of the ink composition is preferably 30 mPa · s or less, and more preferably 20 mPa · s or less.

In addition to the azo compound of the present invention, the ink composition of the present invention may appropriately contain other toning pigments and the like for the purpose of adjusting the subtle hue of black. Even in such a case, the total mass of the pigment contained in the ink composition of the present invention may be in the above range with respect to the total mass of the ink composition.
Examples of toning dyes include yellow (for example, CI Direct Yellow 34, CI Direct Yellow 58, CI Direct Yellow 86, CI Direct Yellow 132, CI Direct Yellow 161, etc. ), Orange (for example, CI Direct Orange 17, CI Direct Orange 26, CI Direct Orange 29, CI Direct Orange 39, CI Direct Orange 49, etc.), Brown, Scarlet (E.g., CI Direct Red 89), red (e.g., CI Direct Red 62, CI Direct Red 75, CI Direct Red 79, CI Direct Red 80, CI Direct Red 84, CI Direct Red 225, CI Direct Red 226), magenta (for example, CI Direct Red 227), violet, blue, navy, cyan (for example, CI Direct Blue 199, CI Acid Blue 249, etc.), green (for example, Acid Green 1) ), Black (for example, CI Acid Black 2), and other dyes having various hues.

The ink composition of the present invention can be used by blending one or more of these toning dyes as long as the effects obtained by the azo compound of the present invention are not impaired. Even in this case, the total amount of the coloring matter contained in the ink composition may be in the above range. The mixing ratio of the azo compound of the present invention to the toning dye is approximately 20: 1 to 1: 2, preferably 10: 1 to 1: 1, depending on the hue of the toning dye and the like. It is.
When the ink composition of the present invention is used as an ink for ink-jet recording, it is preferable to use an ink containing a small amount of inorganic impurities such as metal cation chloride and sulfate in the azo compound of the present invention. The standard of the content of the inorganic impurities is about 1% by mass or less with respect to the total mass of the pigment. The lower limit may be less than the detection limit of the analytical instrument, that is, 0%. In order to produce the azo compound of the present invention with a small amount of inorganic impurities, for example, a method using a reverse osmosis membrane; or a dried product or wet cake of the azo compound of the present invention with an alcohol such as methanol, preferably (C1-C4) alcohol In addition, the mixture may be suspended and purified in a mixed solvent of water and water, and the precipitate may be desalted by a known method such as a method of separating and drying the precipitate by filtration.

Specific examples of water-soluble organic solvents that can be used in preparing the ink composition of the present invention include (C1-C4) alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol or tert-butanol. A carboxylic acid amide such as N, N-dimethylformamide or N, N-dimethylacetamide; a lactam such as 2-pyrrolidone, hydroxyethyl-2-pyrrolidone, N-methyl-2-pyrrolidone or N-methylpyrrolidin-2-one Cyclic cyclic ureas such as 1,3-dimethylimidazolidin-2-one or 1,3-dimethylhexahydropyrimido-2-one; acetone, methyl ethyl ketone, 2-methyl-2-hydroxypentan-4-one, etc. Ketones or ketoalcohols; tetrahydrofuran, dioxa Cyclic ethers such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,4-butylene glycol, 1,6-hexylene glycol, diethylene glycol, triethylene glycol, Mono-, oligo- or polyalkylene glycols or thioglycols having C2-C6 alkylene units such as tetraethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, thiodiglycol or dithiodiglycol; trimethylolpropane, glycerin or hexane-1 , 2,6-triol and other polyols (preferably triol); ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol (C1-C4) alkyl ethers of polyhydric alcohols such as dimethyl monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether (butyl carbitol) triethylene glycol monomethyl ether or triethylene glycol monoethyl ether; γ-butyrolactone; or dimethyl Sulfoxide; and the like. These organic solvents may be used alone or in combination of two or more.
The water-soluble organic solvent mentioned above contains substances that are solid at room temperature, such as trimethylolpropane, but these are water-soluble even when they are solid, and when dissolved in water Since it can be used for the same purpose as the water-soluble organic solvent, it is described in the category of the water-soluble organic solvent for the sake of convenience.

  Hereinafter, antiseptic / antifungal agents, pH adjusters, chelating reagents, rust preventives, water-soluble UV absorbers, water-soluble polymer compounds, dye dissolving agents, antioxidants, and surfactants that can be used as ink preparation agents Describe.

  Examples of the antifungal agent include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, p-hydroxybenzoic acid ethyl ester, 1,2-benzisothiazolin-3-one and salts thereof. These are preferably used in the ink composition in an amount of 0.02 to 1.00% by mass.

  Examples of preservatives include organic sulfur, organic nitrogen sulfur, organic halogen, haloallylsulfone, iodopropargyl, N-haloalkylthio, nitrile, pyridine, 8-oxyquinoline, and benzothiazole. , Isothiazoline, dithiol, pyridine oxide, nitropropane, organotin, phenol, quaternary ammonium salt, triazine, thiazine, anilide, adamantane, dithiocarbamate, brominated indanone, benzyl Examples thereof include bromoacetate-based or inorganic salt-based compounds. Specific examples of organic halogen compounds include sodium pentachlorophenol, specific examples of pyridine oxide compounds include, for example, sodium 2-pyridinethiol-1-oxide, and isothiazoline compounds include, for example, 1,2-benzisothiazolin-3-one, 2-n-octyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4 -Isothiazoline-3-one magnesium chloride, 5-chloro-2-methyl-4-isothiazolin-3-one calcium chloride, 2-methyl-4-isothiazolin-3-one calcium chloride and the like. Specific examples of other antiseptic / antifungal agents include anhydrous sodium acetate, sodium sorbate, sodium benzoate, and the like.

  As the pH adjuster, any substance can be used as long as it can control the pH of the ink within a range of about 5 to 11 without adversely affecting the prepared ink. Specific examples thereof include alkanolamines such as diethanolamine, triethanolamine and N-methyldiethanolamine; hydroxides of alkali metals such as lithium hydroxide, sodium hydroxide and potassium hydroxide; ammonium hydroxide (ammonia water); Or alkali metal carbonates, such as lithium carbonate, sodium carbonate, sodium hydrogencarbonate, potassium carbonate; Alkali metal salts of organic acids, such as potassium acetate; Inorganic bases, such as sodium silicate and disodium phosphate, etc. are mentioned.

  Specific examples of the chelating reagent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate or sodium uracil diacetate.

  Examples of the rust preventive agent include acidic sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite, and the like.

  Examples of the water-soluble ultraviolet absorber include sulfonated benzophenone compounds, benzotriazole compounds, salicylic acid compounds, cinnamic acid compounds, and triazine compounds.

  Examples of the water-soluble polymer compound include polyvinyl alcohol, cellulose derivatives, polyamines and polyimines.

  Examples of the dye dissolving agent include ε-caprolactam, ethylene carbonate, urea, and the like.

  As the antioxidant, for example, various organic and metal complex antifading agents can be used. Examples of the organic anti-fading agent include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines or heterocyclic rings. .

Examples of the surfactant include known surfactants such as anionic, cationic, and nonionic surfactants.
Examples of anionic surfactants include alkyl sulfonates, alkyl carboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, N-acyl amino acids and salts thereof, N-acyl methyl taurate, alkyl sulfate poly Oxyalkyl ether sulfate, alkyl sulfate polyoxyethylene alkyl ether phosphate, rosin acid soap, castor oil sulfate ester, lauryl alcohol sulfate ester, alkylphenol type phosphate ester, alkyl type phosphate ester, alkylaryl sulfonate, diethyl Examples include sulfosuccinate, diethylhexylsylsulfosuccinate, and dioctylsulfosuccinate.

  Examples of the cationic surfactant include 2-vinylpyridine derivatives and poly-4-vinylpyridine derivatives.

  Examples of amphoteric surfactants include lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine, or imidazoline derivatives. Is mentioned.

Nonionic surfactants include ethers such as polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene alkyl ether; Ester systems such as polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, polyoxyethylene stearate; 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl Acetylene glycol (alcohol) series such as lu-1-hexyn-3-ol; trade name Surfynol 104, 105, 82, 465, Olphine STG, etc. manufactured by Nissin Chemical; Polyglycol ether series (for example, SIGMA-ALDRICH) Manufactured by Tergitol 15-S-7, etc.).
The above ink preparation agents are used alone or in combination.

  The ink composition of the present invention can be obtained by mixing and stirring the above components in an arbitrary order. If desired, the obtained ink composition may be subjected to microfiltration with a membrane filter or the like to remove impurities, and when used for ink jet recording, it is preferable to perform the filtration. The pore diameter of the filter for performing microfiltration is usually 1.0 μm to 0.1 μm, preferably 0.8 μm to 0.1 μm.

  The ink composition of the present invention can be used in various fields, but is suitable for a water-based ink for writing, a water-based printing ink, an information recording ink, and the like, and is particularly preferably used as an ink for ink-jet recording. It is suitably used in the ink jet recording method of the present invention.

The ink jet recording method of the present invention is a method of performing recording by using the ink composition of the present invention as an ink, and ejecting ink droplets of the ink in accordance with a recording signal to adhere to a recording material. In the ink jet recording method of the present invention, there are no particular limitations on the ink head, ink nozzles, and the like used for recording, and they can be appropriately selected according to the purpose.
This recording method is a known method, for example, a charge control method that ejects ink using electrostatic attraction force; a drop-on-demand method (pressure pulse method) that uses the vibration pressure of a piezo element; An acoustic ink jet method that irradiates the ink instead of the ink and discharges the ink using the radiation pressure; a thermal ink jet that heats the ink to form bubbles and uses the generated pressure, a so-called bubble jet (registered trademark) method Etc. can be used.

The recording material used in the ink jet recording method of the present invention is not particularly limited. For example, information transmission sheets such as paper and film, fibers and cloths (cellulose, nylon, wool, etc.), leather, and color filter base materials. Among them, an information transmission sheet is preferable.
The information transmission sheet is preferably a surface-treated sheet, specifically, a sheet, a synthetic paper, a film or other base material provided with an ink receiving layer. The ink receiving layer is formed by, for example, impregnating or coating the above-mentioned base material with a cationic polymer; or a porous white inorganic substance capable of absorbing a pigment in the ink, such as porous silica, alumina sol, or special ceramics. And a hydrophilic polymer such as polyvinyl pyrrolidone, and the like.
The information transmission sheet provided with such an ink receiving layer is usually called ink jet dedicated paper (film), glossy paper (film) or the like. Specific examples include Canon Inc., trade name Glossy Pro [Platinum Grade], professional photo paper, super photo paper or matte photo paper; Seiko Epson Corporation trade name, photo paper (gloss), PM matte paper, Krispia; manufactured by Nippon Hewlett-Packard Co., Ltd., trade name: Advanced Photo Paper, Premium Plus Photo Paper, Premium Glossy Film or Photo Paper; etc., are available as commercial products. Of course, plain paper can also be used.

  Among the information transmission sheets described above, it is known that an image recorded on a sheet coated with a porous white inorganic substance has a particularly large discoloration due to ozone gas. However, since the ink composition of the present invention is excellent in ozone gas resistance, a great effect is exhibited even when ink jet recording is performed on such a recording material.

In order to record on a recording material by the ink jet recording method of the present invention, for example, a container containing the above ink composition may be loaded at a predetermined position of an ink jet printer and recorded on the recording material by the above method.
The inkjet recording method of the present invention comprises the black ink composition of the present invention and, for example, the known magenta, cyan, yellow, and green, blue (or violet), red (or orange), etc. as necessary. These ink compositions of the respective colors can also be used in combination.
The ink composition of each color is injected into each container, and each container is loaded into a predetermined position of the ink jet printer and used for ink jet recording in the same manner as the container containing the black ink composition of the present invention.

The colored body of the present invention is
a) The azo compound according to any one of 1) to 5) or a tautomer thereof, or a salt thereof,
b) The water-based ink composition as described in 6) or 7) above, or
c) A substance colored by any one of the three methods of the ink jet recording method described in 8) above [the three of these a) to c)].
Although there is no restriction | limiting in particular about the substance to be colored, The recording material etc. which are used for said inkjet recording method are mentioned preferably.

The azo compound of the present invention is a black pigment. This compound is easy to synthesize and inexpensive, and has a feature of low saturation, and therefore exhibits a more preferable hue as black. Moreover, since it is excellent in water solubility, the filterability with a membrane filter in the process of producing an ink composition is good.
Further, the ink composition of the present invention containing the azo compound is an aqueous black ink composition, and has good storage stability without solid precipitation, physical property change, color change, etc. after long-term storage.
Furthermore, an image recorded with the ink composition of the present invention has particularly high moisture resistance, a very high printing density, low saturation and color rendering, and a high-quality black hue. Excellent fastness such as light resistance, ozone gas resistance and bronze resistance. Further, when used in combination with ink compositions containing magenta, cyan and yellow pigments, full-color ink jet recording with excellent fastness and storage stability is possible.
As described above, the ink composition containing the azo compound of the present invention can be used as an ink for ink jet recording, a writing instrument, and the like, and has excellent ejection stability. Is preferred.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited at all by the following example.
In the text, “parts” and “%” are based on mass unless otherwise specified.
Operations such as each synthesis reaction and crystallization were performed under stirring unless otherwise specified. In the following formulas, acidic functional groups such as sulfo and carboxy are represented in the form of free acid. The pH value and the reaction temperature in the synthesis reaction are both measured values in the reaction system.
Moreover, the maximum absorption wavelength (λmax) of the synthesized compound was measured in an aqueous solution having a pH of 7 to 8, and the measured value of the measured compound was described in Examples. The azo compounds of the present invention synthesized in the following examples all showed a solubility of 100 g / liter or more in water.
When the required amount of the target compound was not obtained by one synthesis reaction, the same synthesis reaction was repeated until the required amount was obtained.

[Example 1]
(Process 1)
In 90.0 parts of water, 6.0 parts of 5-aminoisophthalic acid was added and dissolved to a pH of 6-7 using a 25% aqueous sodium hydroxide solution, and 6.3 parts of a 39.8% aqueous sodium nitrite solution were added. . This solution was added while stirring 12.7 parts of 38% hydrochloric acid and 50.0 parts of ice, and stirred at 10 ° C. or lower for 30 minutes, and then 1.0 part of sulfamic acid was added, and 5-amino A diazotization solution of isophthalic acid was obtained. This diazotized solution was added to a solution obtained by adding 6.7 parts of 8-amino-2-naphthalenesulfonic acid to 250.0 parts of water, using a 25% aqueous sodium hydroxide solution and an ice bath, at a temperature of 10 ° C. or less, pH 4 to 6 was added and added over 30 minutes. After dripping, after reacting for 2 hours under the same conditions, 26.0 parts of sodium chloride was added, and the precipitated crystals were collected by filtration to obtain a wet cake 43.4 containing a compound represented by the following formula (7). Got a part.

(Process 2)
14.5 parts of a wet cake of the compound represented by the formula (7) obtained in Example 1 (Step 1) above was added to 80.0 parts of water, and the pH was adjusted to 6 to 7 using a 25% aqueous sodium hydroxide solution. Then, 1.9 parts of 39.8% aqueous sodium nitrite solution was added. The resulting solution was added to a solution of 50.0 parts of ice and 3.9 parts of 38% hydrochloric acid using an ice bath while maintaining the temperature at 15 ° C. or lower. After reacting for 3 hours under the same conditions, 1.0 part of sulfamic acid was added to obtain a diazotization liquid of the compound of the above formula (7). This diazotization solution was added to a solution of 95.0 parts of water and 9.0 parts of the compound of the following formula (8) obtained by using the method described in JP-A-2006-76908, and a 15% sodium carbonate aqueous solution was added. Added, kept at 5-15 ° C., pH 8-9, added over 1 hour. After reacting for 1 hour under the same conditions, 72.0 parts of sodium chloride was added, and the precipitated crystals were collected by filtration. The obtained crystals were dissolved again in 80.0 parts of water, added to a mixed solution of 200.0 parts of isopropyl alcohol and 200.0 parts of methanol, and the precipitated crystals were collected by filtration. After performing the same operation twice in total, it was dried to obtain 7.5 parts of a sodium salt of a compound represented by the following formula (9) as a black powder. (Λmax: 618 nm)

[Example 2]
(Process 1)
To 110.0 parts of water, 9.1 parts of 5-amino-2-chlorobenzenesulfonic acid was added and dissolved to a pH of 4 to 5 using a 25% aqueous sodium hydroxide solution, and a 39.8% aqueous sodium nitrite solution 9.2. Parts were added. Subsequently, 12.2 parts of 38% hydrochloric acid was added and reacted for 30 minutes, and then 1.0 part of sulfamic acid was added to obtain a diazotized liquid of 5-amino-2-chlorobenzenesulfonic acid. This diazotized solution was added to a solution obtained by adding 8.9 parts of 8-amino-2-naphthalenesulfonic acid to 320.0 parts of water, using a 25% aqueous sodium hydroxide solution and an ice bath, at 10 ° C. or lower, pH 4 to 6 was added and added over 30 minutes. After dripping, after reacting for 1 hour under the same conditions, 116.0 parts of sodium chloride was added, and the precipitated crystals were collected by filtration to obtain 48.1 of a wet cake containing a compound represented by the following formula (10). Got a part.

(Process 2)
11.5 parts of a wet cake of the compound represented by the formula (10) obtained in Example 2 (Step 1) above was added to 90.0 parts of water, and the pH was adjusted to 5 to 6 using a 25% aqueous sodium hydroxide solution. Then, 2.6 parts of 39.8% aqueous sodium nitrite solution was added. The obtained solution was added to a solution of 60.0 parts of ice and 6.2 parts of 38% hydrochloric acid using an ice bath while maintaining the temperature at 15 ° C. or lower. After reacting for 1 hour under the same conditions, 0.5 part of sulfamic acid was added to obtain a diazotization liquid of the compound of the above formula (10). This diazotized liquid was added to a solution of 90.0 parts of water and 14.5 parts of the compound of the above formula (8) obtained by using the method described in JP-A-2006-76908 with a 15% sodium carbonate aqueous solution. Added, kept at 5-15 ° C., pH 8-9, added over 1 hour. After reacting for 5 hours under the same conditions, 40.0 parts of sodium chloride was added, and the precipitated crystals were collected by filtration. The obtained crystals were dissolved again in 100.0 parts of water, added to a mixed solution of 20.0 parts of isopropyl alcohol and 200.0 parts of methanol, and the precipitated crystals were collected by filtration. After performing the same operation twice in total, it was dried to obtain 6.0 parts of a sodium salt of a compound represented by the following formula (11) as a black powder. (Λmax: 614 nm)

［実施例３］
［（Ａ）インクの調製］
上記実施例１（工程２）で得られた本発明の化合物を色素として用い、下記表９に示した組成比で各成分を混合し、固形分が溶解するまでおおよそ１時間攪拌した後、０．４５μｍのメンブランフィルター（商品名、セルロースアセテート系濾紙、アドバンテック社製）で濾過することにより試験用の黒色インク組成物を調製した。

[Example 3]
[(A) Preparation of ink]
Using the compound of the present invention obtained in Example 1 (Step 2) as a dye, the components were mixed at the composition ratio shown in Table 9 below, and stirred for about 1 hour until the solid content was dissolved. A black ink composition for testing was prepared by filtering through a 45 μm membrane filter (trade name, cellulose acetate filter paper, manufactured by Advantech).

[Example 4]
As Comparative Example 1, dyes for Comparative Examples described below were mixed in the same composition ratio as shown in Table 9 in the same manner as in Example 2 to prepare a black ink composition for Comparative Examples by the same method.

[Comparative Example 1]
A comparative ink was prepared in the same manner as in Example 2 except that the pigment of the following formula (12) was used as the black pigment for comparison. The following various tests conducted using this ink are referred to as Comparative Example 1. In addition, the compound of following formula (12) is the compound (17) described in Example 1 in International Publication No. 2007/032377, and was obtained by following the methods described in the literature.

[(B) Inkjet recording]
Using the respective ink compositions obtained in Example 3 and Comparative Example 1, inkjet recording was performed on the following printing paper using an inkjet printer (trade name: Canon IP4100).
Glossy paper 1: Product made by Canon Glossy Pro Platinum Grade PT-101
Glossy paper 2: Product name made by Canon Inc. Glossy Gold GL-101
Glossy paper 3: EPSON brand name Crispia glossy paper 4: Brother Kogyo brand name Photo paper BP71GA4
At the time of printing, as a test piece for hue evaluation, an image pattern is made so that six gradations of reflection densities of 100%, 85%, 70%, 55%, 40%, and 25% are obtained, and dark black A light black gradation recorded matter was obtained, and this was used as a test piece, and the following evaluation test was performed. Further, as test pieces for evaluating moisture resistance, lattice-like image patterns having reflection densities of 100% and 0% were prepared, and the following moisture resistance evaluation tests were performed using these as test pieces. Since the gray scale mode is used in any printing, yellow, cyan and magenta recording liquids other than the black recording liquid are not used in combination.

[(C) Evaluation]
Regarding the recorded image by the aqueous ink composition of the present invention, the density change of the recorded image was measured using a colorimeter manufactured by GRETAG-MACBETH, trade name: SpectroEye. In the color measurement, all were performed under the conditions of D65 as the light source, DIN ND as the density reference, and a viewing angle of 2 °.
[1] Hue evaluation
As the hue evaluation of the printed matter, the saturation C * was measured for portions where L * was 10 to 20. As described above, the printed material used for this evaluation was an image pattern printed so that the reflection density was obtained in several gradations.
The value of chroma C * was calculated using the following formula after measuring CIE a * and b *.
C * = (a * ² + b * ² ) ^1/2
Table 10 shows the measurement results. The following evaluation criteria were used.

○：Ｃ＊＜２３
△：２３≦Ｃ＊≦２７
×：２７＜Ｃ＊

○: C * <23
Δ: 23 ≦ C * ≦ 27
×: 27 <C *

  As is apparent from Table 10, Example 3 had a lower saturation C * than Comparative Example 1 and a good black hue on any printing paper.

光沢紙１、４
○：ΔＥ＜４．６
△：４．６≦ΔＥ≦６．０
×：６．０＜ΔＥ
光沢紙２
○：ΔＥ＜２．０
△：２．０≦ΔＥ≦３．０
×：３．０＜ΔＥ
光沢紙３
○：ΔＥ＜６．０
△：６．０≦ΔＥ≦７．５
×：７．５＜ΔＥ [2] Evaluation of moisture resistance
A constant temperature and humidity machine manufactured by Yamato Scientific Co., Ltd. was used, and a storage test for 7 days was performed on each of the above test pieces under the conditions of a temperature chamber 30 ° C. and a humidity 90% RH. After the test, the brightness L *, a *, and b * of the test pieces before and after the test were measured, and the color difference ΔE was calculated using the following formula. In the following formulas, ΔL *, Δa *, and Δb * mean differences between L *, a *, and b * before and after the test, respectively.
ΔE = (ΔL * ² + Δa * ² + Δb * ² ) ^1/2
The test results are shown in Table 11 below. The following evaluation standards were used.

Glossy paper 1, 4
○: ΔE <4.6
Δ: 4.6 ≦ ΔE ≦ 6.0
×: 6.0 <ΔE
Glossy paper 2
○: ΔE <2.0
Δ: 2.0 ≦ ΔE ≦ 3.0
×: 3.0 <ΔE
Glossy paper 3
○: ΔE <6.0
Δ: 6.0 ≦ ΔE ≦ 7.5
×: 7.5 <ΔE

  As is apparent from Table 11, Example 2 was better in moisture resistance than Comparative Example 1 on any printing paper.

  From the above results, it can be seen that the ink composition using the compound of Example 1 exhibits a good black hue and is superior to Comparative Example 2 in terms of moisture resistance.

  The azo compound of the present invention and the ink composition containing the azo compound are suitably used for black ink for various recordings such as writing utensils, particularly ink jet recording.

Claims (12)

An azo compound represented by the following formula (1), a tautomer thereof, or a salt thereof.

[In Formula (1),
X represents a phenyl group which may have a substituent.
R ^{1 to} R ⁴ are each independently a hydrogen atom; a halogen atom; a cyano group; a carboxy group; a sulfo group; a sulfamoyl group; a (C1-C4) alkyl group; a (C1-C4) alkoxy group; a hydroxy group or (C1 -C4) (C1-C4) alkyl group optionally substituted with an alkoxy group; (C1-C4) alkoxy group optionally substituted with a hydroxy group, (C1-C4) alkoxy group, a sulfo group or a carboxy group; N -Alkylaminosulfonyl group; N-phenylaminosulfonyl group; phospho group; nitro group; acyl group; ureido group; (C1-C4) an acylamino group which may be substituted with an alkoxy group, a sulfo group or a carboxy group.
n represents an integer of 0 or 1. ] In the formula (1),
R ¹ is a carboxy group, a sulfo group, or a (C1-C4) alkoxy group,
R ² is a hydrogen atom or a sulfo group,
The azo compound according to claim 1, or a tautomer thereof, or a salt thereof, wherein any one of R ³ and R ⁴ is a hydrogen atom and the other is a sulfo group. In the formula (1),
X is a (C1-C4) alkyl group substituted with a sulfo group, a carboxy group, a sulfo group or a carboxy group, an unsubstituted (C1-C4) alkyl group, a (C1-C4) alkoxy substituted with a sulfo group or a carboxy group Group, unsubstituted (C1-C4) alkoxy group, (C1-C4) thioalkyl group substituted by sulfo group or carboxy group, halogen atom, nitro group, hydroxy group, amino group, alkylamino group, phenylamino group, acylamino Group, acetyloxy group, p-toluenesulfonyloxy group, alkylsulfonyl group substituted with sulfo group or carboxy group, unsubstituted alkylsulfonyl group, phenylsulfonyl group substituted with sulfo group or carboxy group, unsubstituted phenylsulfonyl group Or a phenyl group substituted with a sulfamoyl group. Azo compound or a tautomer thereof according to 2, or a salt thereof. In the formula (1),
R ¹ is a carboxy group or a sulfo group,
R ² is a hydrogen atom,
Any one of R ³ and R ⁴ is a hydrogen atom, the other is a sulfo group,
X is a sulfo group, a carboxy group, an unsubstituted (C1-C4) alkyl group, a sulfo (C1-C4) alkoxy group, an unsubstituted (C1-C4) alkoxy group, a sulfo (C1-C4) thioalkyl group, a halogen atom, amino A phenyl group substituted with a group, a nitro group, or an acetylamino group,
The azo compound according to any one of claims 1 to 3, or a tautomer thereof, or a salt thereof, wherein n is 1. In the formula (1),
The azo compound according to any one of claims 1 to 4, or a tautomer thereof, or a salt thereof, wherein X is a phenyl group having at least one water-soluble substituent. An aqueous ink composition comprising at least one kind of the azo compound according to any one of claims 1 to 5 or a tautomer thereof, or a salt thereof as a coloring matter. The aqueous ink composition according to claim 7, further comprising a water-soluble organic solvent. An ink jet recording method for performing recording on a recording material by using the ink composition according to claim 6 or 7 as ink and discharging ink droplets of the ink according to a recording signal. The inkjet recording method according to claim 8, wherein the recording material is an information transmission sheet. 10. The ink jet recording method according to claim 9, wherein the information transmission sheet is a sheet having an ink receiving layer containing a porous white inorganic substance. An ink jet printer loaded with a container containing the ink composition according to claim 6. a) the azo compound according to any one of claims 1 to 5 or a tautomer thereof, or a salt thereof;
b) The water-based ink composition according to claim 6 or 7, or
c) A colored body colored by any one of the three methods of the ink jet recording method according to claim 8.