JP2011074211A - Azo compound, ink composition, method for recording and colored article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an azo compound that has high solubility in a medium mainly composed of water, is stable even after long-term storage of a highly concentrated aqueous solution or ink thereof, has high printing density, is excellent in color rendering properties, and gives a colorless and high-grade black recorded image, and to provide an ink composition containing the compound. <P>SOLUTION: There is provided the azo compound represented by formula (1) or a tautomer thereof, or a salt thereof. In the formula, n represents 1 or the like; R<SP>1</SP>represents a 1-4C alkyl group or the like; R<SP>2</SP>represents a cyano group or the like; R<SP>3</SP>and R<SP>4</SP>independently represent a hydrogen atom, a sulfo group, or the like; R<SP>5</SP>represents a sulfo 1-4C alkoxy group or the like; R<SP>6</SP>represents a hydrogen atom or the like; R<SP>7</SP>represents a 3-6C branched chain alkyl group or the like; and R<SP>8</SP>to R<SP>10</SP>independently represent a hydrogen atom, a sulfo group, a 1-4C alkoxy group, or the like. <P>COPYRIGHT: (C)2011,JPO&INPIT

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 inks 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.

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 and the like is strongly demanded for ink jet recorded images. In addition to this, one of the necessary properties of black ink is that the hue does not change greatly depending on the type of recording material. For example, many types of inkjet dedicated paper are commercially available as recording materials that can provide photographic image quality. However, when recording on these special papers with the same black ink, one special paper shows a high-quality black, the other special paper shows a reddish black, and a different special paper shows a bluish black. As shown, a phenomenon occurs in which the hue of black largely changes depending on the type of recording material. Accordingly, there is a need for a black pigment that has a small change in hue even when recorded on different recording materials, and a black ink containing the same.

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 poor metamerism. A polyazo dye having an extended conjugated system generally has problems such as low water solubility, easily causing a bronzing phenomenon in which a 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.

Examples of the black compound (black pigment) for ink jet recording improved with respect to gas resistance, which has become the most important issue in recent years, include compounds described in Patent Documents 1 and 7, for example. Although the gas resistance of these compounds has been improved, they do not fully meet market demands. Further, azo compounds having a benzimidazolopyridone skeleton, which is one of the characteristics of the black pigment of the present invention, are disclosed in Patent Documents 2 to 6 and the like. Patent Documents 3 and 4 also disclose trisazo compounds, but these trisazo compounds are obtained by further bonding two benzimidazolopyridone skeletons with azo structures to both ends of a linking group containing an azo structure. Nothing similar to the asymmetric azo compound of the present invention having a symmetrical structure is disclosed. Patent Documents 6 and 8 disclose the use of a trisazo compound and a water-soluble black compound for inkjet recording.

International Publication No. 2005/054374 Pamphlet International Publication No. 2004/050768 Pamphlet German Patent No. 2000004488 German Patent No. 2023295 JP 05-134435 A International Publication No. 2007/077931 Pamphlet Special table 2007-517082 International Publication No. 2009/069279 Pamphlet

The present invention is a dye having an extremely high print density when recorded on ink jet dedicated paper, having a small hue change even when recorded on a different recording material, low saturation, and high-quality black hue, And an ink composition containing the coloring matter, particularly a black ink composition for inkjet recording.

As a result of intensive studies to solve the problems as described above, the present inventors have found that a specific azo compound can solve the problems, and have completed the present invention. 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),
n is 0 or 1;
R ¹ represents a C1-C4 alkyl group; a C1-C4 alkyl group substituted with a carboxy group; a phenyl group; a phenyl group substituted with a sulfo group; or a carboxy group;
R ² represents a cyano group; a carbamoyl group; or a carboxy group;
R ³ and R ⁴ each independently represent a hydrogen atom; a C1-C4 alkyl group; a halogen atom; a C1-C4 alkoxy group; or a sulfo group;
R ⁵ is a C1-C4 alkoxy group; the substituent is substituted with at least one group selected from the group consisting of a hydroxy group, a C1-C4 alkoxy group, a hydroxy C1-C4 alkoxy group, a sulfo group, and a carboxy group. A C1-C4 alkoxy group;
R ⁶ represents a hydrogen atom or a C1-C4 alkyl group,
R ⁷ represents a C3-C6 branched alkyl group,
R ⁸ to R ¹⁰ are each independently a hydrogen atom; a halogen atom; a carboxy group; a sulfo group; a nitro group; a carbamoyl group; a sulfamoyl group; a C1-C4 alkyl group; a C1-C4 alkoxy group; A C1-C4 alkoxy group substituted with at least one group selected from the group consisting of: a C1-C4 alkoxy group, a hydroxy C1-C4 alkoxy group, a sulfo group, and a carboxy group; or Represents a C1-C4 alkylsulfonyl group substituted with at least one group selected from the group consisting of a hydroxy group, a sulfo group and a carboxy group as a substituent. ],
2)
The azo compound according to 1) above, wherein R ⁷ in formula (1) is isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, sec-pentyl, neopentyl, or tert-pentyl. Or a tautomer thereof, or a salt thereof,
3)
In Formula (1), R ⁵ is a C1-C4 alkoxy group substituted with a sulfo group, or a C1-C4 alkoxy group substituted with a carboxy group, R ⁶ is a hydrogen atom, R ⁷ is a tert-butyl group, or a neopentyl group. Or an azo compound according to 1) or 2) or a tautomer thereof, or a salt thereof, which is a tert-pentyl group,
4)
In formula (1), R ⁸ to R ¹⁰ are each independently a hydrogen atom; a chlorine atom; a carboxy group; a sulfo group; a C1-C4 alkyl group; a C1-C4 alkoxy group; a sulfo C1-C4 alkoxy group; The azo compound or a tautomer thereof according to any one of 1) to 3), or a salt thereof, which is a C4 alkylsulfonyl group;
5)
The azo compound according to any one of 1) to 4) above, wherein R ¹ is a C1-C4 alkyl group or phenyl group, R ² is a cyano group or carbamoyl group, R ³ is a hydrogen atom, and R ⁴ is a sulfo group. Or a tautomer thereof, or a salt thereof,
6)
In equation (1),
n is 1,
R ¹ is a C1-C4 alkyl group or a phenyl group,
R ² is a cyano group or a carbamoyl group,
R ³ is a hydrogen atom,
R ⁴ is a sulfo group,
A C1-C4 alkoxy group in which R ⁵ is substituted with a sulfo group,
R ⁶ is a hydrogen atom,
R ⁷ is a tert-butyl group or a tert-pentyl group,
R ⁸ is a hydrogen atom or a sulfo group,
R ⁹ is a hydrogen atom; a chlorine atom; a carboxy group; a sulfo group; a C1-C4 alkyl group; a C1-C4 alkoxy group; a sulfo C1-C4 alkoxy group; a C1-C4 alkylsulfonyl group;
R ¹⁰ is a hydrogen atom or a sulfo group,
The azo compound according to 1) or a tautomer thereof, or a salt thereof,
7)
In equation (1),
n is 1,
R ¹ is a C1-C4 alkyl group,
R ² is a cyano group,
R ³ is a hydrogen atom,
R ⁴ is a sulfo group,
R ⁵ is a sulfopropoxy group,
R ⁶ is a hydrogen atom,
R ⁷ is a tert-butyl group,
R ⁸ is a hydrogen atom or a sulfo group,
R ⁹ is a C1-C4 alkoxy group R ¹⁰ is a hydrogen atom or a sulfo group,
The azo compound according to 1) or a tautomer thereof, or a salt thereof,
8)
An aqueous ink composition containing at least one kind of the azo compound according to any one of 1) to 7) or a tautomer thereof, or a salt thereof;
9)
The water-based ink composition as described in 8) above, further containing a water-soluble organic solvent,
10)
An ink jet recording method for recording on a recording material by using the ink composition according to 8) or 9) as an ink, and discharging ink droplets of the ink according to a recording signal;
11)
The inkjet recording method according to 10) above, wherein the recording material is an information transmission sheet,
12)
The inkjet recording method according to 11) above, wherein the information transmission sheet is a sheet having an ink receiving layer containing a porous white inorganic substance,
13)
An ink jet printer loaded with a container containing the ink composition described in 8) or 9) above;
14)
a) The azo compound according to any one of 1) to 7) or a tautomer thereof, or a salt thereof,
b) The water-based ink composition as described in 8) or 9) above, or
c) A colored body colored by any one of the three methods described in 10) above,
About.

The azo compound or a salt thereof of the present invention and an ink composition containing the azo compound are preferably used as an ink for ink jet recording. Further, when recorded on ink jet dedicated paper, the print density is very high, and different recording materials. The ink composition containing the azo compound of the present invention is extremely useful as a black ink for ink-jet recording because it has a small hue change, low saturation and a high-quality black hue even when recorded on the ink. .

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.
The azo compound of the present invention represented by the formula (1) has a tautomer, and the tautomer includes the following formulas (2) to (6) in addition to the compound represented by the formula (1). Etc. are considered. These compounds are also included in the present invention. In the formulas (2) to (6), R ^{1 to} R ¹⁰ and n have the same meaning as in the above formula (1).

In the above formula (1), examples of the C1-C4 alkyl group for R ¹ include linear or branched unsubstituted groups, and linear ones are preferred. Specific examples thereof include straight chain such as methyl, ethyl, n-propyl and n-butyl; branched chain such as isopropyl, isobutyl, sec-butyl and tert-butyl; Preferable specific examples include methyl and n-propyl, and methyl is particularly preferable.

Examples of the C1-C4 alkyl group substituted with a carboxy group in R ¹ include those in which any carbon atom of the unsubstituted C1-C4 alkyl group is substituted with a carboxy group. The substitution position of the carboxy group is not particularly limited, but it is preferably substituted at the end of the alkyl group, and the number of substitutions of carboxy is 1 or 2, preferably 1. Specific examples include carboxymethyl and 2-carboxyethyl. Preferred examples include carboxymethyl.

Examples of the phenyl group substituted with a sulfo group in R ¹ include a phenyl group having 1 to 3, preferably 1 or 2 substituted sulfo groups, and the substitution position of the sulfo group is not particularly limited. Specific examples include 3-sulfophenyl, 4-sulfophenyl, 2,4-disulfophenyl, 3,5-disulfophenyl, and the like. A preferred specific example is 4-sulfophenyl.

Preferable R ¹ includes a C1-C4 alkyl group, a C1-C4 alkyl group substituted with a carboxy group, a phenyl group, or a phenyl group substituted with a sulfo group.
More preferably, it is a phenyl group substituted with a C1-C4 alkyl group, a phenyl group, or a sulfo group.
More preferably, it is a C1-C4 alkyl group or a phenyl group.
Particularly preferred is a C1-C4 alkyl group, with methyl being most preferred.

In the above formula (1), R ² represents a cyano group; a carbamoyl group; or a carboxy group. A cyano group or a carbamoyl group is preferable, and a cyano group is more preferable.

In the above formula (1), examples of the C1-C4 alkyl group in R ³ and R ⁴ include the same as the C1-C4 alkyl group in R ¹ including preferable ones.

In R ³ and R ^4, the halogen atom, fluorine atom, chlorine atom, bromine atom, or iodine atom and the like, a chlorine atom is preferable.

Examples of the C1-C4 alkoxy group in R ³ and R ⁴ include a linear or branched unsubstituted group, and a linear one is preferable. Specific examples include straight chain such as methoxy, ethoxy, n-propoxy and n-butoxy; branched chain such as isopropoxy, isobutoxy, sec-butoxy and tert-butoxy; Of these, methoxy is particularly preferred.

R ³ and R ⁴ are each independently preferably a hydrogen atom, a C1-C4 alkoxy group, or a sulfo group.
More preferably, one is a combination of hydrogen atoms and the other is a sulfo group.
The substitution position of R ³ and R ⁴ is not particularly limited. When either one is a hydrogen atom and the other is a sulfo group, the sulfo group is not adjacent to any nitrogen atom constituting the benzimidazolopyridone ring. It is preferable to substitute one of the two carbon atoms.

The compound represented by the above formula (1) of the present invention may be used as a mixture containing at least two kinds of positional isomers at the substitution positions of R ³ and R ⁴ from the viewpoint of ease of synthesis and low cost. good.

As a preferred combination of R ^{1 to} R ⁴ in the formula (1), R ¹ is a C1-C4 alkyl group or a phenyl group (preferably a C1-C4 alkyl group, more preferably a methyl group), and R ² is a cyano group or a carbamoyl group. A combination of a group (preferably a cyano group), R ³ is a hydrogen atom, and R ⁴ is a sulfo group.

Examples of the C1-C4 alkoxy group in R ⁵ include the same as the C1-C4 alkoxy group in R ³ and R ⁴ , including preferred ones.

As a substituent in R ⁵ , C1-C4 alkoxy substituted with at least one group selected from the group consisting of a hydroxy group, a C1-C4 alkoxy group, a hydroxy C1-C4 alkoxy group, a sulfo group, and a carboxy group Examples of the group include those having these substituents on any carbon atom in the C1-C4 alkoxy group. The number of the substituents is usually 1 or 2, preferably 1. The position of the substituent is not particularly limited, but is preferably substituted with a carbon atom other than the carbon atom to which the oxygen atom in the alkoxy group is bonded.
Specific examples include hydroxy C1-C4 alkoxy groups such as 2-hydroxyethoxy, 2-hydroxypropoxy and 3-hydroxypropoxy; methoxyethoxy, ethoxyethoxy, n-propoxyethoxy, isopropoxyethoxy, n-butoxyethoxy, methoxypropoxy , Ethoxypropoxy, n-propoxypropoxy, isopropoxybutoxy, C1-C4 alkoxy C1-C4 alkoxy groups such as n-propoxybutoxy; hydroxy C1-C4 alkoxy C1-C4 alkoxy groups such as 2-hydroxyethoxyethoxy; carboxymethoxy, Carboxy C1-C4 alkoxy groups such as 2-carboxyethoxy and 3-carboxypropoxy; sulfo-C1-C such as 2-sulfoethoxy, 3-sulfopropoxy and 4-sulfobutoxy Alkoxy group; and the like.

Among the above, preferable R ⁵ includes a C1-C4 alkyl group, a C1-C4 alkoxy group substituted with a sulfo group, and a C1-C4 alkoxy group substituted with a carboxy group, and more preferably substituted with a sulfo group. C1-C4 alkoxy group formed.

In the above formula (1), examples of the C1-C4 alkyl group for R ⁶ include the same as the C1-C4 alkyl group for R ¹ , including preferable ones.

In the above formula (1), R ⁷ represents a C3-C6 branched chain alkyl group. Specific examples include isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, isopentyl group, sec-pentyl group, neopentyl group, tert-pentyl group and the like.
Among these, those having a high degree of branching, that is, those having a tertiary carbon atom rather than a secondary carbon atom are preferred. Specific examples include tert-butyl, neopentyl, or tert-pentyl, and tert-butyl is more preferred. preferable.

Preferred combinations of R ^{5 to} R ⁷ include a C1-C4 alkoxy group in which R ⁵ is substituted with a sulfo group, or a C1-C4 alkoxy group substituted with a carboxy group (preferably a C1-C4 substituted with a sulfo group). An alkoxy group), R ⁶ is a hydrogen atom, and R ⁷ is a combination of a tert-butyl group, a neopentyl group, or a tert-pentyl group.
Particularly preferably, R ⁵ is a C1-C4 alkoxy group substituted with a sulfo group (preferably sulfopropoxy, more preferably 3-sulfopropoxy), R ⁶ is a hydrogen atom, and R ⁷ is a combination of tert-butyl groups. .

In the above formula (1), examples of the halogen atom in R ⁸ to R ¹⁰ include the same halogen atoms as those in R ³ and R ⁴ , including preferable ones.

In the above formula (1), examples of the C1-C4 alkyl group in R ⁸ to R ¹⁰ include the same as the C1-C4 alkyl group in R ¹ including preferable ones.

Examples of the C1-C4 alkoxy group in R ⁸ to R ¹⁰ include the same C1-C4 alkoxy groups as those in R ³ and R ⁴ , including preferable ones.

C1 substituted by at least one group selected from the group consisting of a hydroxy group, a C1-C4 alkoxy group, a hydroxy C1-C4 alkoxy group, a sulfo group, and a carboxy group as a substituent in R ⁸ to R ¹⁰ Examples of the —C4 alkoxy group include the same ones as the C1-C4 alkoxy group substituted with the same group in R ⁵ , including preferable ones.

Examples of the C1-C4 alkylsulfonyl group in R ⁸ to R ¹⁰ include straight-chain or branched-chain groups, and straight-chain groups are preferred. Specific examples thereof include linear ones such as methylsulfonyl, ethylsulfonyl, n-propylsulfonyl and n-butylsulfonyl; branched ones such as isopropylsulfonyl and isobutylsulfonyl;
Of the above, methylsulfonyl, ethylsulfonyl, and isopropylsulfonyl are preferable, and methylsulfonyl is particularly preferable.

As the substituent in R ⁸ to R ¹⁰ , the C1-C4 alkylsulfonyl group substituted with at least one group selected from the group consisting of a hydroxy group, a sulfo group, and a carboxy group includes the above C1-C4 alkylsulfonyl What substituted the said group to the arbitrary carbon atoms in group is mentioned, The number of this substituent is 1 or 2 normally, Preferably it is 1. The position of the substituent is not particularly limited.
Specific examples include hydroxy-substituted compounds such as hydroxyethylsulfonyl and 2-hydroxypropylsulfonyl; sulfo-substituted compounds such as 2-sulfoethylsulfonyl and 3-sulfopropylsulfonyl; 2-carboxyethylsulfonyl and 3-carboxypropylsulfonyl. Carboxy-substituted ones such as;

Among the above, R ⁸ to R ¹⁰ are each independently a hydrogen atom; a chlorine atom; a carboxy group; a sulfo group; a C1-C4 alkyl group; a C1-C4 alkoxy group; a sulfo C1-C4 alkoxy group; A sulfonyl group;

At least one of R ⁸ to R ¹⁰ is preferably a group other than a hydrogen atom, and at least one of them is more preferably a sulfo group or a carboxy group (preferably a sulfo group).

R ⁸ is preferably a hydrogen atom or sulfo.
R ⁹ is preferably a chlorine atom, carboxy, sulfo, nitro, carbamoyl, sulfamoyl, C1-C4 alkyl group, C1-C4 alkoxy or C1-C4 alkylsulfonyl group, more preferably C1-C4 alkoxy.
R ¹⁰ is preferably a hydrogen atom or sulfo.

As a preferable combination of R ⁸ to R ¹⁰ , R ⁸ is a hydrogen atom, R ⁹ is a chlorine atom, carboxy, sulfo, nitro, carbamoyl, sulfamoyl, C1-C4 alkyl group, C1-C4 alkoxy group, or C1-C4 alkylsulfonyl. A group, R ¹⁰ is sulfo; or R ⁸ is sulfo, R ⁹ is chlorine atom, carboxy, sulfo, nitro, carbamoyl, sulfamoyl, C1-C4 alkyl group, C1-C4 alkoxy group or C1-C4 alkylsulfonyl A group wherein R ¹⁰ is a hydrogen atom; More preferable combinations include a combination in which R ⁸ is a hydrogen atom, R ⁹ is a C1-C4 alkoxy group, and R ¹⁰ is sulfo; or R ⁸ is sulfo, R ⁹ is a C1-C4 alkoxy group, and R ¹⁰ is a hydrogen atom. A combination of

The substitution position of R ⁸ to R ¹⁰ on the benzothiazole ring is not particularly limited, but the position of the sulfur atom in the benzothiazole ring is the 1st position, R ⁸ is the 4th or 5th position (preferably the 5th position), and R ⁹ is The 6-position and R ¹⁰ are preferably substituted at the 7-position.

The compound which combined the preferable thing described about the various substituents in the said Formula (1), its combination, its substitution position, etc. is more preferable, and what combined the more preferable things is still more preferable. The same applies to preferable combinations, preferable combinations, and more preferable combinations.

Specific examples of preferable combinations in the formula (1) include the following combinations (i) to (iii). (Ii) is preferable to (i), and (iii) is most preferable.
(I)
n is 1,
R ¹ is a C1-C4 alkyl group or a phenyl group,
R ² is a cyano group or a carbamoyl group,
R ³ is a hydrogen atom,
R ⁴ is a sulfo group,
A C1-C4 alkoxy group in which R ⁵ is substituted with a sulfo group,
R ⁶ is a hydrogen atom,
R ⁷ is a tert-butyl group or a tert-pentyl group,
R ⁸ is a hydrogen atom or a sulfo group,
R ⁹ is a hydrogen atom; a chlorine atom; a carboxy group; a sulfo group; a C1-C4 alkyl group; a C1-C4 alkoxy group; a sulfo C1-C4 alkoxy group; a C1-C4 alkylsulfonyl group;
A combination in which R ¹⁰ is a hydrogen atom or a sulfo group.
(Ii)
n is 1,
R ¹ is a C1-C4 alkyl group,
R ² is a cyano group,
R ³ is a hydrogen atom,
R ⁴ is a sulfo group,
R ⁵ is a sulfopropoxy group,
R ⁶ is a hydrogen atom,
R ⁷ is a tert-butyl group,
R ⁸ is a hydrogen atom or a sulfo group,
A combination in which R ⁹ is a C1-C4 alkoxy group R ¹⁰ is a hydrogen atom or a sulfo group.
(Iii)
n is 1,
R ¹ is a methyl group,
R ² is a cyano group,
R ³ is a hydrogen atom,
R ⁴ is a sulfo group,
R ⁵ is a sulfopropoxy group,
R ⁶ is a hydrogen atom,
R ⁷ is a tert-butyl group,
R ⁸ is a hydrogen atom or a sulfo group,
A combination in which R ⁹ is a C1-C4 alkoxy group R ¹⁰ is a hydrogen atom or a sulfo group.

The azo compound represented by the above formula (1) can be synthesized, for example, by the following method. In addition, the structural formula of the compound in each step shall be expressed in the form of a free acid, and in the following formulas (7) to (12), R ¹ to R ¹⁰ and n are the same as those in formula (1). Has meaning.
The compound represented by the following formula (7) is diazotized by a conventional method, and this is coupled with a compound represented by the following formula (8) by a conventional method to obtain a compound represented by the following formula (9). .

The compound represented by the formula (9) thus obtained was diazotized by a conventional method, and this was then coupled with a compound represented by the following formula (10) by a conventional method to obtain a compound represented by the following formula (11). To obtain a compound.

The compound represented by the formula (11) thus obtained is diazotized by a conventional method, and then this and a compound represented by the following formula (12) are subjected to a coupling reaction by a conventional method, whereby the above formula (1) The azo compound of this invention represented by these can be obtained.

The compound represented by the above formula (12) can be synthesized according to the method described in Patent Document 4.

Although it does not specifically limit as a suitable specific example of the azo compound of this invention represented by Formula (1), The compound shown by the structural formula given to the following Table 2 thru | or 5 etc. is mentioned.
In each table, functional groups such as sulfo group and carboxy group are described in the form of free acid for convenience.

The diazotization of the compound represented by the above formula (7) is carried out by a method known per se. For example, it is carried out using nitrosylsulfuric acid in an inorganic acid medium such as sulfuric acid and phosphoric acid or in an organic acid medium such as acetic acid and propionic acid, for example, at a temperature of −10 to 20 ° C., preferably 0 to 10 ° C. Coupling of the diazotized compound of the compound represented by formula (9) and the compound represented by formula (8) is also carried out under conditions known per se. It is carried out in water or an aqueous organic medium, for example at a temperature of -5 to 30 ° C, preferably 5 to 20 ° C. The compounds represented by formula (7) and formula (8) are used in approximately stoichiometric amounts.

The diazotization of the compound represented by the above formula (9) is carried out by a method known per se. For example, it is carried out in an inorganic acid medium using a nitrite, for example an alkali metal nitrite such as sodium nitrite, at a temperature of, for example, -5 to 30 ° C, preferably 5 to 20 ° C. Coupling of the diazotized compound of the compound represented by formula (9) and the compound represented by formula (10) 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 30 ° C., preferably 5 to 25 ° C., as well as a weakly acidic to weakly alkaline pH value, for example pH 5-10. The pH value is adjusted by adding a base. Examples of the base that can be used include alkali metal hydroxides such as lithium hydroxide and sodium hydroxide, alkali metal carbonates such as lithium carbonate, sodium carbonate, and potassium carbonate, acetates such as sodium acetate, ammonia, and organic amines. . The compound represented by formula (9) and the compound represented by formula (10) are used in approximately stoichiometric amounts.

The diazotization of the compound represented by the formula (11) is also carried out by a method known per se. For example, it is carried out using a nitrite, for example an alkali metal nitrite such as sodium nitrite, in an inorganic acid medium, for example at a temperature of 0 to 40 ° C., preferably 0 to 30 ° C. Coupling of the diazotized compound of the compound represented by formula (11) and the compound represented by formula (12) 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 0 to 50 ° C., preferably 5 to 30 ° C., and at a slightly acidic to alkaline pH value. It is preferably carried out at a weakly acidic to weakly alkaline pH value, for example, pH 5 to 10, and the pH value is adjusted by adding a base. As the base, the same ones as described above can be used. The compounds represented by formulas (11) and (12) are used in approximately stoichiometric amounts.

The salt of the azo compound represented by the 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 (13). 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 above formula (13), 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 represented by Z ^{1 to} Z ⁴ in the formula (13) include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl and the like. Specific examples include hydroxy C1-C4 alkyl groups such as hydroxymethyl, hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 4-hydroxybutyl, 3-hydroxybutyl, 2-hydroxybutyl, etc., and hydroxyalkoxyalkyl groups Examples of the hydroxy C include hydroxyethoxymethyl, 2-hydroxyethoxyethyl, 3-hydroxyethoxypropyl, 2-hydroxyethoxypropyl, 4-hydroxyethoxybutyl, 3-hydroxyethoxybutyl, 2-hydroxyethoxybutyl and the like. Examples include 1-C4 alkoxy C1-C4 alkyl group, among which hydroxyethoxy C1-C4 alkyl is preferable. Particularly preferred are hydrogen atoms; hydroxy C1-C4 alkyl groups such as methyl, hydroxymethyl, hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 4-hydroxybutyl, 3-hydroxybutyl, 2-hydroxybutyl, hydroxy And hydroxyethoxy C1-C4 alkyl groups such as ethoxymethyl, 2-hydroxyethoxyethyl, 3-hydroxyethoxypropyl, 2-hydroxyethoxypropyl, 4-hydroxyethoxybutyl, 3-hydroxyethoxybutyl, 2-hydroxyethoxybutyl and the like. .

Specific examples of combinations of Z ¹ , Z ² , Z ³ , and Z ^{4 that} are preferable as the formula (13) are shown in Table 1 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 formula (1) is used as a desired salt include alkali metal halogen salts such as lithium chloride, sodium chloride and potassium chloride; lithium carbonate, sodium carbonate and potassium carbonate Alkali metal carbonates such as lithium hydroxide, sodium hydroxide, potassium hydroxide and other alkali metal hydroxides; ammonium ion halogen salts such as ammonium chloride and ammonium bromide; ammonium hydroxide (ammonia water), etc. And ammonium ion hydroxides.
Examples of the organic cation salt include, for example, halogen salts of quaternary ammonium ions represented by the above formula (13) such as diethanolamine hydrochloride and triethanolamine hydrochloride.

The ink composition of the present invention will be described. The azo compound represented by the formula (1) of the present invention can dye a material made of cellulose by forming an aqueous composition containing the compound. In addition, materials having a carbonamide bond can be dyed, and can be widely used for dyeing leather, fabrics, paper, 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.

A reaction liquid containing the compound represented by the formula (1), for example, a reaction liquid after completion of the final step in the synthesis reaction of the compound represented by the 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 formula (1) of the present invention as a pigment. It is a water-based ink composition containing. 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, black, etc. The other pigment | dye which has a hue is mentioned.
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 and water. The mixture may be suspended and purified by stirring in a mixed solvent, and the salt may be desalted by a known method such as a method in which the precipitate is separated by filtration and dried;

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; N Carboxylic acid amides such as N, N-dimethylformamide or N, N-dimethylacetamide; Lactams such as 2-pyrrolidone, hydroxyethyl-2-pyrrolidone, N-methyl-2-pyrrolidone or N-methylpyrrolidin-2-one; 1 Cyclic ureas such as 1,3-dimethylimidazolidin-2-one or 1,3-dimethylhexahydropyrimido-2-one; ketones such as acetone, methyl ethyl ketone, 2-methyl-2-hydroxypentan-4-one Or keto alcohol; tetrahydrofuran, dioxane, etc. Cyclic ether; 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, tetraethylene Mono-, oligo- or polyalkylene glycols or thioglycols having C2-C6 alkylene units such as glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, thiodiglycol or dithiodiglycol; trimethylolpropane, glycerin or hexane-1,2 Polyol (preferably triol) such as 1,6-triol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol C1-C4 alkyl ethers of polyhydric alcohols such as 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; can give. 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 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 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, ejecting ink droplets of the ink in accordance with a recording signal, and attaching them 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: Professional Photo Paper, Super Photo Paper, or Matt Photo Paper; Seiko Epson Corporation, trade name: Photo Paper (Glossy), PM Matt Paper, Crispia; Japan Hewlett-Packard Co. Made by company, product name Advanced Photo Paper, Premium Plus Photo Paper, Premium Glossy Film or Photo Paper, etc., and 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) and red (or orange) as necessary, as described above. 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 7) or a tautomer thereof, or a salt thereof,
b) The water-based ink composition as described in 8) or 9) above, or
c) A substance colored by any one of the three methods [the three of a) to c)] of the ink jet recording method described in 10) above.
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.
An image recorded with the ink composition of the present invention has a very high printing density without causing bronzing, and has a small hue change and low saturation even when recorded on different recording materials, and a high-quality black color. Have a hue of. Excellent fastness such as light resistance, (ozone) gas resistance, moisture resistance, and water resistance. Further, when used in combination with ink compositions containing magenta, cyan and yellow dyes, 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.

Example 1
(Process 1)
4.2 parts of 2-amino-6-methoxybenzothiazole was slowly added at 15-25 ° C. in 21.5 parts of 12% fuming sulfuric acid. After the addition, the mixture was stirred at the same temperature for 2 hours and then dropped into 45 parts of ice water in about 10 minutes. The precipitated solid was separated by filtration to obtain 10.0 parts of a mixture of the compound represented by the following formula (14) and the following formula (15) as a wet cake.

(Process 2)
16.5 parts of 2-amino-4-tert-butylphenol was dissolved in 30 parts of N-methylpyrrolidone, and 10.7 parts of acetic anhydride was added dropwise in about 10 minutes. After dripping, it heated at 40-50 degreeC and reacted at the same temperature for 2 hours. After cooling to room temperature, 90 parts of water was added and stirred for 1 hour, and the precipitated solid was separated by filtration to obtain 32.3 parts of a wet cake of a compound represented by the following formula (16).

(Process 3)
After adding 32.3 parts of a wet cake of the compound represented by the formula (16) obtained in Example 1 (Step 2) and 14.7 parts of potassium carbonate to 60 parts of 2-propanol, the mixture was heated to 70 ° C. . To this solution, a mixed solution of 11.7 parts of 1,3-propane sultone and 5 parts of 2-propanol was added dropwise over 10 minutes. After dropping, the mixture was heated to 80 ° C. and reacted at the same temperature for 2 hours. After cooling to 60 ° C., 31.6 parts of 35% hydrochloric acid was added dropwise in about 10 minutes, and then heated to 90 ° C. After reacting at 90-95 ° C. for 2 hours, it was cooled to room temperature. 150 parts of saturated saline was added to this reaction liquid, and after stirring for 1 hour, the precipitated solid was separated by filtration and dried to obtain 17.2 parts of a compound represented by the following formula (17).

(Process 4)
13.5 parts of concentrated sulfuric acid was added to 10.2 parts of crushed ice and cooled in an ice bath to obtain a sulfuric acid solution at 0 to 5 ° C. To this liquid, 10.0 parts of a wet cake of a mixture of the compounds represented by formulas (14) and (15) obtained in Example 1 (Step 1) was added in about 10 minutes, and about 30 at 0 to 5 ° C. Stir for minutes. 2.1 parts of 60% nitric acid was added to the obtained liquid, and 7.1 parts of 40% nitrosylsulfuric acid was added dropwise at 0-5 ° C. in about 5 minutes, followed by reaction at the same temperature for 1 hour to obtain a diazo reaction liquid. It was.
On the other hand, 5.7 parts of the compound represented by the formula (17) obtained in Example 1 (Step 3) and 1.0 part of sulfamic acid were added to 120 parts of warm water at 40 to 50 ° C., and 25% hydroxylation was performed. A sodium aqueous solution was added to adjust the pH to 5.5 to 6.5 to obtain a suspension. To this suspension, 50 parts of crushed ice was added to adjust the liquid temperature to 5 to 10 ° C., and then the diazo reaction liquid was added dropwise at 5 to 15 ° C. for about 30 minutes. At this time, crushed ice was added to maintain a liquid temperature of 5 to 15 ° C., and after completion of the dropwise addition, the mixture was reacted at the same temperature for 1 hour, and the precipitated solid was separated by filtration to obtain the following formula (18) and formula (19). 30.6 parts of a wet cake of a mixture with the represented compound was obtained.

(Process 5)
Suspension obtained by adding 30.6 parts of a wet cake of a mixture of the compound represented by the formula (18) and the formula (19) obtained in Example 1 (Step 4) and 40 parts of crushed ice to 100 parts of water. 25% aqueous sodium hydroxide solution was added to adjust the pH of the suspension to about 1.0. The liquid temperature was kept at 5 to 10 ° C. in an ice bath, 2.9 parts of 35% hydrochloric acid and 2.8 parts of 40% aqueous sodium nitrite were added, and the mixture was reacted at the same temperature for 1 hour to obtain a diazo reaction liquid. .
Meanwhile, 4.2 parts of 2-amino-5-hydroxynaphthalene-1,7-disulfonic acid is added to 50 parts of water, and a 25% aqueous sodium hydroxide solution is added to adjust the pH to 7.5 to 8.0. Obtained. To this aqueous solution, the above diazo reaction solution was added dropwise at a reaction temperature of 15 to 25 ° C. for about 30 minutes. At this time, the pH value of the reaction solution was adjusted to 7.5 to 8.0 by adding sodium carbonate, and the reaction was further continued for 2 hours while maintaining the adjustment of the temperature and pH. Sodium chloride was added to the reaction solution for salting out, and the precipitated solid was separated by filtration to obtain 61.0 parts of a wet cake of a mixture of the compound represented by the following formula (20) and the following formula (21). .

(Step 6)
To 200 parts of water, 30.5 parts of a wet cake of a mixture of the compound represented by Formula (20) and Formula (21) obtained in Example 1 (Step 5) was added and stirred for 1 hour to obtain an aqueous solution. It was. After adding 100 parts of crushed ice to this solution and cooling to 0 to 5 ° C., 2.0 parts of 35% hydrochloric acid and 1.0 part of 40% sodium nitrite aqueous solution were added, and the mixture was reacted at the same temperature for 1 hour. A liquid was obtained.
On the other hand, 1.6 parts of a compound represented by the following formula (22) obtained by the method described in Patent Document 7 is added to 100 parts of water, and a 25% aqueous sodium hydroxide solution is added to adjust the pH to 7.5 to 8.5. To obtain an aqueous solution. The diazo reaction liquid obtained above was dropped into this aqueous solution at 5 to 15 ° C. for about 30 minutes. At this time, sodium carbonate was added to maintain the pH of the reaction solution at 7.5 to 8.5, and the reaction was further continued for 2 hours while maintaining the same temperature and pH adjustment. Sodium chloride was added to the reaction solution for salting out, and the precipitated solid was separated by filtration to obtain 22.6 parts of a wet cake. The obtained wet cake was dissolved in 280 parts of water, and the pH was adjusted to 7.0 to 7.5 with 35% hydrochloric acid. Then, 27.4 parts of lithium chloride was added and stirred for 1 hour to obtain an aqueous solution. 350 parts of 2-propanol was added and the precipitated solid was separated by filtration to obtain a wet cake. The obtained wet cake was dissolved in 80 parts of water, 350 parts of 2-propanol was added, and the precipitated solid was separated by filtration to obtain a wet cake. The obtained wet cake was dissolved again in 50 parts of water, 250 parts of 2-propanol was added, and the precipitated solid was separated by filtration and dried, thereby obtaining the following formula (23) and formula (24) of the present invention. 4.4 parts of a mixture with the represented compound was obtained as a mixed salt of sodium and lithium.
λmax: 590 nm.

Example 2
(A) Preparation of Ink After obtaining the black ink composition of the present invention by mixing the components shown in Table 7 below, evaluation was performed by separating impurities with a 0.45 μm membrane filter. An ink was prepared. This ink preparation is referred to as Example 2.
Ion exchange water was used as water for ink preparation. Further, at the time of preparing the ink, the pH of the ink was adjusted to pH 7 to 9 with lithium hydroxide, and ion exchanged water was added to prepare a total amount of 100 parts.
In addition, Nissin Chemical Co., Ltd. product name Surfinol 104PG50 was used as the surfactant in Table 7 below.

The ink composition of the present invention and the ink obtained by microfiltration of the ink composition did not cause precipitation separation during storage, and did not change physical properties even after long-term storage.

Comparative Example 1
Instead of the azo compound of the present invention obtained in the Examples, the same procedure as in Example 2 was used except that a mixture of the following formula (25) and the dye of the following formula (26) disclosed in Example 7 of Patent Document 8 was used. Comparative inks were prepared. The preparation of this comparative ink is referred to as Comparative Example 1.

Comparative Example 2
Ink for comparison in the same manner as in Example 2 except that the dye of the following formula (27) disclosed in Example 2-6 of Patent Document 6 is used in place of the azo compound of the present invention obtained in Examples. Was prepared. This ink preparation is referred to as Comparative Example 2.

(B) Inkjet recording Using the inks obtained in Examples and Comparative Examples, inkjet recording was performed on the following two types of information recording sheets (inkjet dedicated paper) using a Canon inkjet printer, product name PIXUS iP4500.

Glossy paper 1: manufactured by EPSON, product name: photographic paper Krispia (high gloss)
Glossy paper 2: manufactured by Canon Inc., trade name: Canon photo paper, Glossy Gold (GL101)

During ink jet recording, an image pattern is created so that six levels of gradations of 100%, 80%, 60%, 40%, 20%, and 10% density can be obtained, and a dark black to light black gradation recorded matter. The following evaluation test was carried out using this as a test piece.

(C) Color measurement of recorded image Each test piece obtained using the ink prepared in each of the comparative examples was measured using a colorimeter manufactured by GRETAG-MACBETH, trade name: SpectroEye. In the color measurement, all were performed under the conditions of DIN, viewing angle 2 °, and light source D65 based on the density standard.
Each evaluation was performed on glossy papers 1 and 2.
The specific evaluation method is as follows. The results of the evaluation test are collectively shown in Table 8 below.

1) Saturation test The CIE a * value and b for each gradation portion where the black reflection density Dk value of the recorded image in each test piece is in the range of 1.0 to 1.5 using the above colorimeter. * The value was measured. The saturation C * value was calculated from the obtained a * value and b * value using the following formula.
C * = (a * ² + b * ² ) ^1/2

The color was evaluated according to the following criteria. As a high-quality black hue, a saturation close to 0 is superior.

○: C * is less than 35 Δ: C * is 35 or more and less than 45 ×: C * is 45 or more

2) Print density test 1
Using the above colorimetric system, the black reflection density Dk value was measured at the gradation portion of 100% density printed most darkly. The value was evaluated according to the following criteria. The evaluation results are shown in Table 32. A larger Dk value represents a higher print density and is superior in quality.
◎: Dk value is 2.50 or more ○: Dk value is less than 2.50 2.40 or more Δ: Dk value is less than 2.40 2.30 or more ×: Dk value is less than 2.30

3) Print density test 2
Using the above colorimetric system, the black reflection density Dk value was measured at the 80% density gradation portion printed second darkly. The value was evaluated according to the following criteria. The evaluation results are shown in Table 32. A larger Dk value represents a higher print density and is superior in quality.
◎: Dk value is 2.35 or more ○: Dk value is less than 2.35 2.15 or more Δ: Dk value is less than 2.15 2.00 or more ×: Dk value is less than 2.00

4) Hue change test Glossy paper 3 was manufactured by Canon Inc. under the trade name Canon Photographic Paper Platinum Grade (PT101), and ink jet recording was performed on glossy paper 3 in the same manner as “(B) Inkjet recording”. A specimen was obtained. For the three test pieces of glossy paper 1, glossy paper 2, and glossy paper 3, the CIE L *, a *, and b * were measured in the same manner as in “(C) Color measurement of recorded image”, and the gloss was measured. Using the paper 3 as a reference, the color difference ΔE between the glossy paper 1 and the glossy paper 2 was obtained. For colorimetry, a 60% density gradation portion was used. The smaller the color difference, the smaller the hue change between different recording materials, and the better the quality.
In addition, in the following evaluation criteria, as for Δ and ×, the change in hue is large enough to be confirmed visually.
Evaluation was performed according to the following criteria.
◎: ΔE is less than 3.0 ○: ΔE is 3.0 or more and less than 5.0 Δ: ΔE is 5.0 or more and less than 6.5 ×: ΔE is 6.5 or more

As is apparent from the results in Table 8, it can be seen that the ink of Example 1 has a much lower saturation than that of Comparative Example 2, and an achromatic and high-quality black image can be obtained. Further, the print density is better than any of the comparative examples. Further, it was revealed that Comparative Examples 1 and 2 have a large change in hue between different recording materials.
Therefore, the azo compound of the present invention and the ink composition containing the azo compound are extremely useful for recording, particularly for inkjet recording.

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 (14)

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

[In Formula (1),
n is 0 or 1;
R ¹ represents a C1-C4 alkyl group; a C1-C4 alkyl group substituted with a carboxy group; a phenyl group; a phenyl group substituted with a sulfo group; or a carboxy group;
R ² represents a cyano group; a carbamoyl group; or a carboxy group;
R ³ and R ⁴ each independently represent a hydrogen atom; a C1-C4 alkyl group; a halogen atom; a C1-C4 alkoxy group; or a sulfo group;
R ⁵ is a C1-C4 alkoxy group; the substituent is substituted with at least one group selected from the group consisting of a hydroxy group, a C1-C4 alkoxy group, a hydroxy C1-C4 alkoxy group, a sulfo group, and a carboxy group. A C1-C4 alkoxy group;
R ⁶ represents a hydrogen atom or a C1-C4 alkyl group,
R ⁷ represents a C3-C6 branched alkyl group,
R ⁸ to R ¹⁰ are each independently a hydrogen atom; a halogen atom; a carboxy group; a sulfo group; a nitro group; a carbamoyl group; a sulfamoyl group; a C1-C4 alkyl group; a C1-C4 alkoxy group; A C1-C4 alkoxy group substituted with at least one group selected from the group consisting of: a C1-C4 alkoxy group, a hydroxy C1-C4 alkoxy group, a sulfo group, and a carboxy group; or Represents a C1-C4 alkylsulfonyl group substituted with at least one group selected from the group consisting of a hydroxy group, a sulfo group and a carboxy group as a substituent. ]. The azo compound according to claim 1, wherein R ⁷ in formula (1) is an isopropyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an isopentyl group, a sec-pentyl group, a neopentyl group, or a tert-pentyl group. Or a tautomer thereof, or a salt thereof. In Formula (1), R ⁵ is a C1-C4 alkoxy group substituted with a sulfo group, or a C1-C4 alkoxy group substituted with a carboxy group, R ⁶ is a hydrogen atom, R ⁷ is a tert-butyl group, or a neopentyl group. Or an azo compound or a tautomer thereof, or a salt thereof according to claim 1 or 2, which is a tert-pentyl group. In formula (1), R ⁸ to R ¹⁰ are each independently a hydrogen atom; a chlorine atom; a carboxy group; a sulfo group; a C1-C4 alkyl group; a C1-C4 alkoxy group; a sulfo C1-C4 alkoxy group; The azo compound according to any one of claims 1 to 3, or a tautomer thereof, or a salt thereof, which is a C4 alkylsulfonyl group. The azo compound or the azo compound according to any one of claims 1 to ⁴ , wherein R ¹ is a C1-C4 alkyl group or a phenyl group, R ² is a cyano group or a carbamoyl group, R ³ is a hydrogen atom, and R ⁴ is a sulfo group. A tautomer thereof, or a salt thereof. In equation (1),
n is 1,
R ¹ is a C1-C4 alkyl group or a phenyl group,
R ² is a cyano group or a carbamoyl group,
R ³ is a hydrogen atom,
R ⁴ is a sulfo group,
A C1-C4 alkoxy group in which R ⁵ is substituted with a sulfo group,
R ⁶ is a hydrogen atom,
R ⁷ is a tert-butyl group or a tert-pentyl group,
R ⁸ is a hydrogen atom or a sulfo group,
R ⁹ is a hydrogen atom; a chlorine atom; a carboxy group; a sulfo group; a C1-C4 alkyl group; a C1-C4 alkoxy group; a sulfo C1-C4 alkoxy group; a C1-C4 alkylsulfonyl group;
R ¹⁰ is a hydrogen atom or a sulfo group,
The azo compound according to claim 1 or a tautomer thereof, or a salt thereof. In equation (1),
n is 1,
R ¹ is a C1-C4 alkyl group,
R ² is a cyano group,
R ³ is a hydrogen atom,
R ⁴ is a sulfo group,
R ⁵ is a sulfopropoxy group,
R ⁶ is a hydrogen atom,
R ⁷ is a tert-butyl group,
R ⁸ is a hydrogen atom or a sulfo group,
R ⁹ is a C1-C4 alkoxy group R ¹⁰ is a hydrogen atom or a sulfo group,
The azo compound according to claim 1 or a tautomer thereof, or a salt thereof. An aqueous ink composition comprising at least one kind of the azo compound according to any one of claims 1 to 7 or a tautomer thereof, or a salt thereof as a dye. The water-based ink composition according to claim 8, further comprising a water-soluble organic solvent. An ink jet recording method in which recording is performed on a recording material by using the ink composition according to claim 8 or 9 as ink and discharging ink droplets of the ink in accordance with a recording signal. The inkjet recording method according to claim 10, wherein the recording material is an information transmission sheet. 12. The ink jet recording method according to claim 11, 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 8. a) the azo compound according to any one of claims 1 to 7 or a tautomer thereof, or a salt thereof;
b) The water-based ink composition according to claim 8 or 9, or
c) A colored body colored by any one of the three methods of the ink jet recording method according to claim 10.