JP2016204438A - Water-soluble azo compound and salt thereof, ink composition and colored body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-soluble yellow pigment (compound) having high water solubility and excellent in a variety of fastness such as water proofness, moisture proofness, ozone gas resistance, wear resistance, and light resistance, particularly excellent in ozone gas resistance, and to provide a yellow ink composition for printing, particularly for ink-jet printing, including the same.SOLUTION: The present invention provides, for example, a water-soluble azo compound illustrated by formula (16) or salt thereof.SELECTED DRAWING: None

Description

  The present invention relates to a water-soluble azo compound or a salt thereof, an ink composition containing the same, and a colored body colored with these.

Among various color recording methods, various ink ejection methods have been developed as recording methods using an ink jet printer, which is one of the representative methods. These all generate ink droplets and attach them to various recording materials (paper, film, fabric, etc.) for recording. In this method, since the recording head and the recording material are not in direct contact with each other, no noise is generated and the method is quiet. In addition, since it has the characteristics that it is easy to downsize, speed up, and colorize, it has been rapidly spreading in recent years and is expected to grow greatly in the future.
Conventionally, inks such as fountain pens and felt pens, and inks for ink-jet recording have been used in which water-soluble pigments (dyes) are dissolved in an aqueous medium. In general, a water-soluble organic solvent is added to these water-based inks in order to prevent clogging of ink at a pen tip or an ink discharge nozzle. These inks give a recorded image of sufficient density, do not cause clogging of the pen tip and nozzles, have good drying properties on the recording material, have little bleeding, and have excellent storage stability. Such performance is required.

  Ink jet nozzle clogging occurs when the water in the ink evaporates in the vicinity of the nozzle before other solvents and additives, and the pigment solidifies and precipitates when the composition state is low in water and high in solvents and additives. There are many things that come from doing. Accordingly, one of the very important required performances is that solids are not easily deposited even when the moisture content in the ink is low. For this reason, high solubility in solvents and additives is one of the properties required for pigments. As a method for eliminating nozzle clogging, a method using a dye having a high printing density is known. By using a pigment having a high printing density, the pigment content in the ink can be reduced while maintaining the conventional printing density. This not only makes it difficult to precipitate the dye, but is also advantageous in terms of cost, and development of a dye having a high printing density is desired.

By the way, in order to record image or character information on a color display of a computer in color by an ink jet printer, generally a subtraction method using four colors of ink of yellow (Y), magenta (M), cyan (C), and black (K). Mixed colors are used, whereby the recorded image is expressed in color. In order to reproduce an additive color mixture image of red (R), green (G), and blue (B) on a CRT (CRT) display etc. as faithfully as possible with a subtractive color mixture image, each dye used in the ink, particularly Y, Each of M and C is desired to have a hue close to a standard color and to be clear. The clearness mentioned here generally means having a high saturation. When the three primary colors Y, M, and C with low saturation are used, the color area that can be expressed in a single color or mixed color becomes narrow, and the range of the color area that is desired to be expressed may be insufficient. For this reason, development of highly saturated pigments and inks containing them is desired.
In addition, the ink performance is required to be stable for long-term storage, high in recorded image density, and excellent in fastness such as water resistance, moisture resistance, light resistance and gas resistance. It is done.
Here, the gas resistance means that a gas having an oxidizing action (also referred to as an oxidizing gas) existing in the air reacts with a dye (dye) of a recorded image on the recording material or in the recording material to record. This is the resistance to the phenomenon of discoloration of images. Among oxidizing gases, ozone gas is considered to be a main causative substance that promotes the discoloration and fading phenomenon of ink jet recorded images. Since this discoloration phenomenon is characteristic of ink jet recorded images, improvement of ozone gas resistance is an important technical problem in this field.

With the recent development of inkjet technology, the speed of inkjet recording (printing) has been remarkably improved. For this reason, similar to laser printers using electronic toner, there is a market trend to use inkjet printers for printing documents on plain paper, which is the main application in office environments. Inkjet printers have the advantage that the type of recording paper is not limited and the price of the printer itself is low, and it is becoming increasingly popular especially in small to medium-sized office environments such as small offices and home offices (SOHO). As described above, when an inkjet printer is used for printing on plain paper, hue, color (printing) density, and water resistance tend to be more important among the qualities required for printed matter.
In order to satisfy these performances, a method using a pigment ink has been proposed. However, since pigment ink does not dissolve in water-based ink, it does not enter a solution state, but is a dispersed ink. Therefore, when this is used for ink jet recording, there are problems with the stability of the ink itself and the nozzles of the recording head. Problems such as clogging occur. In addition, when pigment ink is used, there is often a problem in abrasion resistance. In the case of a dye ink, such a problem is considered to be relatively difficult to occur. However, in particular, the water resistance is extremely inferior to that of a pigment ink, and an improvement to the problem is strongly desired. In addition, unlike pigment ink, dye ink tends to cause a problem that a dye attached to the surface of plain paper by ink jet recording penetrates more quickly toward the back side of the paper, resulting in a decrease in color density.

  One method for obtaining a photographic image-recorded inkjet image is to provide an ink-receiving layer on the surface of a recording material. The ink receiving layer provided for such a purpose often contains a porous white inorganic substance in order to speed up drying of the ink and to reduce bleeding of the pigment with high image quality. However, particularly in such a recording material, the color fading due to the ozone gas is noticeable. With the recent spread of digital cameras and color printers, there are increasing opportunities to print images obtained with digital cameras and the like as photographic image quality at home, so the above-mentioned color change of recorded images due to oxidizing gas is regarded as a problem. . Compared to the other three primary colors, magenta and cyan, yellow dyes have been proposed that have good resistance to oxidizing gas as well as light resistance. However, a yellow pigment and yellow ink for ink-jet recording that sufficiently satisfy the high sharpness and various fastnesses required by the market have not been obtained yet.

  In recent years, in addition to the above-mentioned performance, the characteristics required of pigments include less harm to humans and the environment. The aniline derivatives used in conventional existing pigments are recognized to be highly harmful, are subject to laws and regulations regarding their use and discharge, work under extremely strict protective equipment, and the remaining raw materials contained in pigments. It is a limiting factor for improving safety and health management and production efficiency such as volume restrictions.

  Examples of known yellow pigments for inkjet which are excellent in water solubility and sharpness include C.I. I. (Color index) Direct yellow 132 is exemplified. Patent Documents 1 to 3 include C.I. I. An example in which (color index) direct yellow 132 is used for inkjet is disclosed. Patent Document 4 discloses an example in which a yellow pigment that can be produced by the method disclosed in Example 1 of Patent Document 5 is used for inkjet.

JP-A-11-70729 Japanese Patent No. 3346755 Japanese Patent No. 4100800 International Publication No. 2011/122426 International Publication No. 2009/154142 Japanese Patent No. 5366819

  An object of the present invention is to provide a water-soluble yellow pigment (compound) having high solubility in water and excellent ozone gas resistance, and a yellow ink composition for various recordings containing the same, particularly for inkjet recording.

  As a result of intensive investigations, the present inventors have found that a water-soluble azo compound represented by a specific formula and an ink composition containing the same solve the above-described problems. Completed the invention.

（式中、Ｒ^１は水素原子、ハロゲン原子、カルボキシ基、カルバモイル基、スルホ基、スルファモイル基、ヒドロキシ基、アミノ基、シアノ基、ホスホ基、ニトロ基、アシル基、（Ｃ１〜Ｃ４）アルキル基（ヒドロキシ基、カルボキシ基、カルバモイル基、及びスルホ基から選択される１又は２以上の置換基で置換されても良い）、（Ｃ１〜Ｃ４）アルコキシ基（ヒドロキシ基、カルボキシ基、カルバモイル基、及びスルホ基から選択される１又は２以上の置換基で置換されても良い）、（Ｃ１〜Ｃ４）スルホアルキル基（ヒドロキシ基、カルボキシ基、カルバモイル基、及びスルホ基から選択させる１又は２以上の置換基で置換されても良い）、（Ｃ１〜Ｃ４）アルキルチオ基（ヒドロキシ基、カルボキシ基、カルバモイル基、及びスルホ基から選択される１又は２以上の置換基で置換されていても良い）、（Ｃ１〜Ｃ４）アルキルアミノ基（ヒドロキシ基、カルボキシ基、カルバモイル基、及びスルホ基から選択させる１又は２以上の置換基で置換されても良い）、又はアシルアミノ基を表し、nは０乃至４の整数を表す。またＲ^５は、（Ｃ３〜Ｃ１０）アルキル基を表す。）
２）
上記式（１）において、Ｒ^１が水素原子である上記１）に記載のインクジェット用水溶性アゾ化合物、
３）
上記式（１）において、ｎが２又は３である上記１）又は２）に記載の水溶性アゾ化合物又はその塩、
４）
上記１）乃至３）のいずれか一項に記載の水溶性アゾ化合物又はその塩を含有するインク組成物、
５）
水溶性有機溶剤をさらに含有する上記４）に記載のインク組成物、
６）
インクジェット記録用である上記４）又は５）に記載のインク組成物、
７）
上記４）乃至６）のいずれか一項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付着させ、記録を行うインクジェット記録方法、
８）
被記録材が情報伝達用シートである上記７）に記載のインクジェット記録方法、
９）
情報伝達用シートが普通紙又は多孔性白色無機物を含むインク受容層を有するシ−トである上記８）に記載のインクジェット記録方法、
１０）
（ａ）上記１）乃至３）のいずれか一項に記載の水溶性アゾ化合物又はその塩、
（ｂ）上記１）乃至３）のいずれか一項に記載の水溶性アゾ化合物又はその塩を含有するインク組成物、又は、
（ｃ）上記１）乃至３）のいずれか一項に記載の水溶性アゾ化合物又はその塩及び水溶性有機溶剤を含有するインク組成物、のいずれかにより着色された着色体、
１１）
上記７）に記載のインクジェット記録方法により着色された着色体、
１２）
上記４）に記載のインク組成物を含む容器が装填されたインクジェットプリンタ、に関する。 That is, the present invention
1)
A water-soluble azo compound represented by the following formula (1) or a salt thereof,

Wherein R ¹ is a hydrogen atom, halogen atom, carboxy group, carbamoyl group, sulfo group, sulfamoyl group, hydroxy group, amino group, cyano group, phospho group, nitro group, acyl group, (C1-C4) alkyl group. (May be substituted with one or more substituents selected from a hydroxy group, a carboxy group, a carbamoyl group, and a sulfo group), a (C1-C4) alkoxy group (a hydroxy group, a carboxy group, a carbamoyl group, and 1 or 2 or more substituents selected from a sulfo group), (C1-C4) sulfoalkyl group (hydroxy group, carboxy group, carbamoyl group, and 1 or 2 or more selected from a sulfo group) (May be substituted with a substituent), (C1-C4) alkylthio group (hydroxy group, carboxy group, carbamoyl group, and sulfo) 1 or 2 or more substituents selected from a group), (C1-C4) alkylamino group (hydroxy group, carboxy group, carbamoyl group, and sulfo group selected from 1 or 2 or more) Or an acylamino group, n represents an integer of 0 to 4. R ⁵ represents a (C3 to C10) alkyl group.)
2)
In the formula (1), the water-soluble azo compound for inkjet according to 1) above, wherein R ¹ is a hydrogen atom,
3)
In the above formula (1), n is 2 or 3, the water-soluble azo compound or salt thereof according to 1) or 2),
4)
An ink composition containing the water-soluble azo compound or salt thereof according to any one of 1) to 3) above;
5)
The ink composition as described in 4) above, further comprising a water-soluble organic solvent,
6)
The ink composition according to 4) or 5), which is for inkjet recording;
7)
An ink jet recording method in which the ink composition according to any one of 4) to 6) above is used as an ink, and ink droplets of the ink are ejected in accordance with a recording signal to adhere to a recording material, and recording is performed;
8)
The inkjet recording method according to 7) above, wherein the recording material is an information transmission sheet,
9)
The inkjet recording method according to 8), wherein the information transmission sheet is a sheet having a paper or an ink receiving layer containing a porous white inorganic substance,
10)
(A) The water-soluble azo compound or a salt thereof according to any one of 1) to 3) above,
(B) an ink composition containing the water-soluble azo compound or salt thereof according to any one of 1) to 3) above;
(C) A colored body colored with any one of the water-soluble azo compound or salt thereof according to any one of 1) to 3) above and an ink composition containing a water-soluble organic solvent,
11)
A colored body colored by the ink jet recording method described in 7) above;
12)
The present invention relates to an ink jet printer loaded with a container containing the ink composition described in 4) above.

  The water-soluble azo compound of the present invention represented by the above formula (1) or a salt thereof has a high solubility in water, and for example, in the process of producing the ink composition of the present invention containing the compound or a salt thereof, It has the characteristic that the filterability with respect to a membrane filter is favorable. In addition, an image recorded by the ink composition of the present invention containing the compound of the present invention is particularly excellent in ozone gas resistance as compared with the image using the conventional compound. As described above, the water-soluble azo compound of the present invention represented by the formula (1) or a salt thereof, and the ink composition containing the same are extremely useful for various recording ink applications, particularly ink jet recording ink applications. It is.

The present invention will be described in detail.
The water-soluble azo compound of the present invention represented by the above formula (1) or a salt thereof is a water-soluble yellow dye. In the present specification, unless otherwise specified, acidic functional groups such as sulfo groups and carboxy groups are represented in the form of free acids. Further, as described above, the present invention includes both the water-soluble azo compound represented by the formula (1) or a salt of the compound, but it is complicated to always describe both of them as “compound or salt thereof”. It is. Therefore, unless otherwise specified, for convenience, the “water-soluble azo compound of the present invention or a salt thereof” including both the “water-soluble azo compound of the present invention” will be simply described as “the (water-soluble azo) compound of the present invention”.

The compound of the present invention is represented by the above formula (1).
In formula (1), R ¹ is a hydrogen atom, halogen atom, carboxy group, carbamoyl group, sulfo group, sulfamoyl group, hydroxy group, amino group, cyano group, phospho group, nitro group, acyl group, (C1 to C4) An alkyl group (which may be substituted with one or more substituents selected from a hydroxy group, a carboxy group, a carbamoyl group, and a sulfo group), a (C1-C4) alkoxy group (a hydroxy group, a carboxy group, a carbamoyl group) , And may be substituted with one or more substituents selected from a sulfo group), (C1-C4) sulfoalkyl groups (1 or 2 selected from a hydroxy group, a carboxy group, a carbamoyl group, and a sulfo group) May be substituted with the above substituents), (C1-C4) alkylthio groups (hydroxy groups, carboxy groups, carbamoyl groups, and 1 or 2 or more substituents selected from a sulfo group, which may be substituted with 1 or 2 or more substituents selected from a rupho group), (C1-C4) alkylamino group (hydroxy group, carboxy group, carbamoyl group, and sulfo group) Represents an acylamino group, and n represents an integer of 0 to 4. R ⁵ represents a (C3 to C10) alkyl group.

In the formula (1), R ¹ is preferably a hydrogen atom, a halogen atom, a carboxy group, a carbamoyl group, a sulfamoyl group, a hydroxy group or a nitro group, more preferably a hydrogen atom, a hydroxy group or a nitro group. Particularly preferred is a hydrogen atom.
n represents an integer of 0 to 4, preferably 2 or 3.
R ⁵ represents a C3 to C10 alkyl group, which may be linear or branched, and may be cyclic. Among these, a C3-C10 branched alkyl group is preferable, a C3-C6 branched alkyl group is more preferable, and an i-propyl group or a t-butyl group is particularly preferable. Most preferably, it is a t-butyl group.

Of the above R ¹ and R ⁵ , compounds in which preferable ones are combined are more preferable, and compounds in which more preferable ones are combined are more preferable. The same applies to combinations of preferable and more preferable ones.

The compound represented by the above formula (1) can be produced, for example, as follows. Ar appropriately used in the following formulas (2) to (6) is a group represented by the following formula (7), ring A means a naphthalene ring represented by the following formula (8), and R ^{1, R 5} denotes the same as ^R 1, ^{R 5} in the formula (1), * represents a bonding position. X represents a halogen atom.

  A hydrazine derivative represented by the following formula (4) is obtained by diazotizing an aromatic amine compound represented by the following formula (2) and reducing it with sodium sulfite or tin chloride. Alternatively, a hydrazine derivative represented by the following formula (4) can be obtained by reacting an aromatic halide represented by the following formula (3) with hydrazine.

  Next, a pyrazolone compound represented by the following formula (5) is obtained by condensing the compound of the above formula (4) with ethyl pivaloyl acetate.

  Next, the compound of the present invention represented by the above formula (1) can be obtained by diazotizing the compound represented by the following formula (6) and coupling with the compound represented by the above formula (5). it can.

  Specific examples of the compound of the present invention of the above formula (1) are shown in the following Table 1, but the present invention is not limited to these specific examples.

  In addition, * of the naphthalene ring in the following Table 1 represents the bonding position to the azo bond.

The compound of the above formula (1) exists also as a free acid or a salt thereof. Examples of the salt of the compound of the above formula (1) include salts with inorganic or organic cations. Specific examples of the inorganic cation salt include alkali metal salts such as lithium salts, sodium salts, potassium salts and the like; and ammonium salts (NH ₄ ⁺ ). Examples of the organic cation include, but are not limited to, quaternary ammonium represented by the following formula (9).

In the above formula (9), Z ^{1 to} Z ⁴ each independently represent a hydrogen atom, a C1-C4 alkyl group, a hydroxy C1-C4 alkyl group, or a hydroxy C1-C4 alkoxy C1-C4 alkyl group, and Z ¹ -Z ^At least one of ⁴ is a group other than a hydrogen atom.

Here, examples of the C1-C4 alkyl group in Z ^{1 to} Z ⁴ include methyl, ethyl and the like. Similarly, examples of the hydroxy C1-C4 alkyl group include hydroxymethyl, hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 4-hydroxybutyl, 3-hydroxybutyl, 2-hydroxybutyl and the like. Similarly, examples of the hydroxy C1-C4 alkoxy C1-C4 alkyl group include hydroxyethoxymethyl, 2-hydroxyethoxyethyl, 3- (hydroxyethoxy) propyl, 3- (hydroxyethoxy) butyl, 2- (hydroxyethoxy ) Butyl and the like.

  Among the above salts, preferred are alkali metal salts such as sodium, potassium and lithium; organic quaternary ammonium salts such as monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine and triisopropanolamine salts; Ammonium salt; and the like. Of these, lithium salts, sodium salts, and ammonium salts are more preferable.

As will be apparent to those skilled in the art, the salt or free acid of the compound of formula (1) can be easily obtained by the following method or the like.
For example, in the synthesis reaction of the compound of formula (1), a water-soluble organic solvent such as acetone or C1-C4 alcohol is added to the reaction solution after completion of the final step or an aqueous solution containing a salt of the compound of formula (1). The solid salt precipitated by the method of adding; the method of salting out by adding sodium chloride; and the like are filtered and separated to obtain the sodium salt of the compound of the above formula (1) as a wet cake.
Further, after dissolving the obtained sodium salt wet cake in water, an acid such as hydrochloric acid is added to adjust the pH appropriately, and the precipitated solid is separated by filtration, whereby the free acid of the compound of the above formula (1) is obtained. Or a mixture of a free acid and a sodium salt in which a part of the compound of the formula (1) is a sodium salt.
Also, after dissolving the obtained sodium salt wet cake or its dry solid in water, an ammonium salt such as ammonium chloride is added, and an acid such as hydrochloric acid is added to adjust the pH appropriately, for example, to pH 1 to 3, By separating the precipitated solid by filtration, an ammonium salt of the compound of the above formula (1) can be obtained. A mixture of an ammonium salt of the compound of formula (1) and a sodium salt of the compound of formula (1) by appropriately adjusting the amount or / and pH of ammonium chloride to be added; or the free acid of the compound of formula (1) And a mixture of ammonium salts;
Further, as described later, a free acid solid can be directly obtained by adding a mineral acid (for example, hydrochloric acid, sulfuric acid, etc.) to the reaction solution after completion of the above reaction. In this case, the wet cake of the free acid of the compound of formula (1) is added to water and stirred, for example, potassium hydroxide; lithium hydroxide; ammonia water; or water of organic quaternary ammonium of formula (9) By adding an oxide; etc. to form a salt, a potassium salt, a lithium salt, an ammonium salt, or a quaternary ammonium salt according to each added compound can be obtained. By limiting the number of moles of the above-mentioned hydroxide to be added with respect to the number of moles of free acid, for example, a mixed salt of lithium salt and sodium salt, etc .; and a mixture of lithium salt, sodium salt, and ammonium salt Salts and the like can also be prepared. The salt of the compound of the above formula (1) may change the physical properties such as solubility or the ink performance when used as an ink depending on the type of the salt. For this reason, it is also preferable to select the type of salt according to the intended ink performance.

  After completion of the reaction, the compound of the present invention of the above formula (1) can be isolated as a solid free acid by adding a mineral acid such as hydrochloric acid, and the resulting free acid solid is water or, for example, hydrochloric acid water or the like. By washing with acidic water, inorganic salts (inorganic impurities) contained as impurities, such as sodium chloride and sodium sulfate, can be removed. As described above, the free acid of the compound of the present invention obtained as described above is obtained by treating the obtained wet cake or its dried solid with a desired inorganic or organic base in water to give a salt of the corresponding compound. Solution. Examples of the inorganic base include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; alkali metal carbonates such as lithium carbonate, sodium carbonate, and potassium carbonate; and ammonium hydroxide (ammonia water). And the like. Examples of the organic base include, but are not limited to, organic amines corresponding to the quaternary ammonium represented by the above formula (9), for example, alkanolamines such as diethanolamine and triethanolamine.

  The compounds of the present invention are suitable for the dyeing of natural and synthetic fiber materials or blends, and also for the production of writing inks and ink jet recording ink compositions. For example, the reaction liquid after completion of the final step in the synthesis reaction of the compound of the present invention represented by the formula (1) can be directly used for the production of the ink composition of the present invention. However, for example, after the reaction solution or the like is dried by the above-described method or a spray drying method to isolate the compound, the obtained compound can be processed into an ink composition.

  In the ink composition of the present invention, the compound of the above formula (1) is dissolved in water or a mixed solution (also referred to as an aqueous medium) of water and a water-soluble organic solvent (an organic solvent that can be mixed with water). An ink preparation agent is added as necessary. When this ink composition is used as an ink for an ink jet printer, a metal cation chloride contained as an impurity, such as sodium chloride; sulfate, such as sodium sulfate; Is preferred. In this case, for example, the total content of sodium chloride and sodium sulfate is about 1% by mass or less with respect to the total mass of the compound of formula (1), and the lower limit is 0% by mass, that is, below the detection limit of the detection instrument. Good. As a method for producing a compound having a small amount of inorganic impurities, for example, a method using a known reverse osmosis membrane; or a dry product or a wet cake of the compound of the present invention, for example, acetone or C1-C4 alcohol (for example, methanol, ethanol, In addition to a water-soluble organic solvent such as isopropanol or the like, or a water-containing water-soluble organic solvent, suspension purification or crystallization methods, and the like can be mentioned. Desalination treatment or the like may be performed by these methods.

  In the ink composition of the present invention, the compound of the above formula (1) is usually 0.1 to 20% by mass, preferably 1 to 10% by mass, more preferably 2 to 8% by mass in the total mass of the ink composition. contains.

  The ink composition of the present invention is prepared using water as a medium, and may optionally contain a water-soluble organic solvent and an ink preparation agent as long as the effects of the present invention are not impaired.

  The water-soluble organic solvent dissolves the dye; prevents the composition from drying (maintains a wet state); adjusts the viscosity of the composition; promotes penetration of the dye into the recording material; adjusts the surface tension of the composition; In some cases, the ink composition of the present invention is preferably contained.

  Examples of the ink preparation agent include antiseptic / antifungal agents, pH adjusting agents, chelating reagents, rust preventive agents, ultraviolet absorbers, viscosity adjusting agents, dye dissolving agents, antifading agents, surface tension adjusting agents, antifoaming agents, etc. Known additives may be mentioned.

  The content of the water-soluble organic solvent is 0 to 60% by mass, preferably 10 to 50% by mass, and the ink preparation agent is 0 to 20% by mass, preferably 0, based on the total mass of the ink composition of the present invention. It is good to use ~ 15 mass%. In the ink composition of the present invention, the balance other than the compound of the above formula (1), the water-soluble organic solvent, and the ink preparation agent is water.

  Examples of the water-soluble organic solvent include C1-C4 alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol and tert-butanol; N, N-dimethylformamide, N , N-dimethylacetamide and the like; 2-pyrrolidone, N-methyl-2-pyrrolidone, hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidin-2-one or 1,3-dimethylhexahydropyrimido Heterocyclic ketones such as 2-one; ketones or ketoalcohols such as acetone, methyl ethyl ketone, 2-methyl-2-hydroxypentan-4-one; cyclic ethers such as tetrahydrofuran, dioxane; ethylene glycol, 1, 2- or 1,3-propylene glycol, 1,2 Or mono having a C2-C6 alkylene unit such as 1,4-butylene glycol, 1,6-hexylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, thiodiglycol, Oligo, or polyalkylene glycol or thioglycol; polyol (preferably triol) such as trimethylolpropane, glycerin, hexane-1,2,6-triol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol Monoethyl ether, diethylene glycol monobutyl ether (butyl carbitol), triethylene Recall monomethyl ether, C1-C4 monoalkyl ether of polyhydric alcohol such as triethylene glycol monoethyl ether; .gamma.-butyrolactone; dimethyl sulfoxide; and the like.

  The water-soluble organic solvent includes a substance that is solid at room temperature, such as trimethylolpropane. However, even if the substance or the like is solid, it shows water solubility, and an aqueous solution containing the substance or the like shows the same properties as the water-soluble organic solvent and can be used with the expectation of the same effect. Therefore, in this specification, for the sake of convenience, such a solid substance is included in the category of a water-soluble organic solvent as long as it can be used in expectation of the same effect as described above.

  Preferred as the water-soluble organic solvent are isopropanol, glycerin, mono-, di- or triethylene glycol, dipropylene glycol, 2-pyrrolidone, hydroxyethyl-2-pyrrolidone, N-methyl-2-pyrrolidone, trimethylolpropane and Butyl carbitol is preferable, and isopropanol, glycerin, diethylene glycol, 2-pyrrolidone, N-methyl-2-pyrrolidone and butyl carbitol are more preferable. These water-soluble organic solvents are used alone or in combination.

Examples of the antiseptic / antifungal agent include organic sulfur, organic nitrogen sulfur, organic halogen, haloallylsulfone, iodopropargyl, N-haloalkylthio, benzothiazole, nitrile, pyridine, 8-oxyquinoline, isothiazoline, dithiol, pyridine oxide, nitropropane, organotin, phenol, quaternary ammonium salt, triazine, thiadiazine, anilide, adamantane, dithiocarbamate, bromo Indanone compound, benzyl bromacetate compound, inorganic salt compound and the like can be mentioned. An example of the organic halogen compound is sodium pentachlorophenol.
Examples of pyridine oxide compounds include sodium 2-pyridinethiol-1-oxide.
Examples of the isothiazoline-based compound include 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-isothiazolin-3-one magnesium chloride, 5-chloro-2-methyl-4-isothiazolin-3-one calcium chloride, 2-methyl-4-isothiazolin-3-one calcium chloride, etc. Can be mentioned.
Other antiseptic / antifungal agents include sodium acetate, sodium sorbate, sodium benzoate and the like; and further trade names Proxel ^RTM GXL (S) and Proxel ^RTM XL-2 (S) manufactured by Arch Chemical Co., etc. Each is listed. In the present specification, the superscript “RTM” means a registered trademark.

  As the pH adjuster, any substance can be used as long as it can control the pH of the ink within the range of 6.0 to 11.0 for the purpose of improving the storage stability of the ink. For example, alkanolamines such as diethanolamine and triethanolamine; hydroxides of alkali metals such as lithium hydroxide, sodium hydroxide and potassium hydroxide; ammonium hydroxides; or alkali metals such as lithium carbonate, sodium carbonate and potassium carbonate And carbonates; aminosulfonic acids such as taurine; and the like.

  Examples of the chelating reagent include disodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uracil diacetate, and the like.

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

  Examples of the ultraviolet absorber include benzophenone compounds, benzotriazole compounds, cinnamic acid compounds, triazine compounds, and stilbene compounds. In addition, a compound that absorbs ultraviolet rays such as a benzoxazole-based compound and emits fluorescence, a so-called fluorescent whitening agent, and the like can also be used.

  Examples of the viscosity modifier include water-soluble polymer compounds in addition to water-soluble organic solvents, such as polyvinyl alcohol, cellulose derivatives, polyamines, and polyimines.

  Examples of the dye solubilizer include urea, ε-caprolactam, ethylene carbonate, and the like. Of these, urea is preferably used.

  The anti-fading agent is used for the purpose of improving image storage stability. As the antifading agent, various organic and metal complex antifading agents can be used. Examples of organic anti-fading agents include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, and heterocycles, and metal complexes Examples thereof include nickel complexes and zinc complexes.

  Examples of the surface tension adjusting agent include surfactants, and examples thereof include anionic surfactants, amphoteric surfactants, cationic surfactants, and nonionic surfactants.

  Examples of anionic surfactants include alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, N-acyl amino acids and salts thereof, N-acyl methyl taurate, alkyl sulfate polyoxyalkyl ethers 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, diethylsulfosuccinate Salts, diethylhexylsulfosuccinate, dioctylsulfosuccinate and the like.

  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, and other imidazoline derivatives. Etc.

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 -1-hexyne-3-acetylene glycol (alcohol) -based ol; Nissin Chemical Industry Co., Ltd. trade name Surfynol ^RTM 104, 82, 465, Olfine ^RTM STG; SIGMA-ALDRICH Corp. Product Name Tergitol ^RTM 15-S-7;

  Examples of antifoaming agents include highly oxidized oils, glycerin fatty acid esters, fluorines, and silicone compounds.

  These ink preparation agents are used alone or in combination. The surface tension of the ink composition of the present invention is usually 25 to 70 mN / m, preferably 25 to 60 mN / m, and the viscosity is preferably 30 mPa · s or less, more preferably 20 mPa · s or less.

  In the production of the ink composition of the present invention, there is no particular limitation on the order of dissolving each agent such as an additive. The water used for preparing the ink composition is preferably water with few impurities such as ion exchange water and distilled water. Further, if necessary, after the ink composition is prepared, fine filtration may be performed using a membrane filter or the like to remove impurities in the ink composition. In particular, when the ink composition of the present invention is used as an ink for ink jet recording, it is preferable to perform microfiltration. The pore size of the filter used for microfiltration is usually 1 to 0.1 μm, preferably 0.8 to 0.1 μm.

  The ink composition containing the compound of the present invention is suitable for use in printing, copying, marking, writing, drawing, stamping, or recording (printing), particularly in inkjet recording. In addition, the ink composition of the present invention is less likely to precipitate solids even when dried in the vicinity of the nozzles of the recording head of an ink jet printer, and for this reason, the recording head is also less likely to block.

  As a method for recording on a recording material by the ink jet recording method of the present invention, the following method may be mentioned. That is, a container filled with the ink composition of the present invention is loaded into a predetermined position of an ink jet printer, the ink composition of the present invention is used as ink, and ink droplets of the ink are ejected according to a recording signal to be recorded. This is a method for recording on a material. Some inkjet printers use, for example, a piezo method using mechanical vibration; a bubble jet (registered trademark) method using bubbles generated by heating; and the like. The ink jet recording method of the present invention can be used by any method.

  In order to obtain a higher-definition recorded image, there are cases where two types of ink containing the same pigment are loaded into one inkjet printer. The difference between the two types of inks is the pigment content, one of which has a high content and the other of which has a low content, and is used as an ink set. The ink composition of the present invention can also be used as such an ink set. Further, the ink composition of the present invention may be used for one of the ink sets, and a known ink (composition) may be used for the other.

  The ink composition of the present invention may be a yellow ink composition containing the compound of the present invention and a known yellow dye for the purpose of fine-tuning the hue within the range that does not impair the effects obtained by the present invention. In addition, the compound of the present invention can be used in combination with a magenta dye or a cyan dye for the purpose of toning inks of other colors, such as black ink, or for preparing red ink or green ink. Furthermore, for the purpose of obtaining a full-color recorded image, the ink composition of the present invention can be used in combination with inks of various colors such as magenta, cyan, and, if necessary, green, blue (or violet), red, and black. . In this case, each color ink may be filled in each container, and these containers may be loaded into a predetermined position of the ink jet printer and used for ink jet recording.

Examples of the recording material used in the inkjet recording method of the present invention include information transmission sheets such as paper and film, fibers and fabrics (cellulose, nylon, wool, etc.), leather, base materials for color filters, and the like. A transmission sheet is preferred. The information transmission sheet is not particularly limited, and a plain paper as well as a surface-treated sheet, specifically, a paper, synthetic paper, a substrate such as a film provided with an ink receiving layer, or the like is used. The ink receiving layer is a layer having an action such as absorbing ink and accelerating its drying. The ink receiving layer is formed by, for example, a method of impregnating or coating the base material with a cationic polymer; inorganic fine particles capable of absorbing the pigment in the ink, together with a hydrophilic polymer such as polyvinyl alcohol or polyvinylpyrrolidone, on the surface of the base material. It is provided by the method of coating; Examples of the material of the inorganic fine particles that can absorb the coloring matter in the ink include porous silica, alumina sol, and special ceramics.
The information transmission sheet having such an ink receiving layer is usually called an inkjet exclusive paper, an inkjet exclusive film, a glossy paper, a glossy film or the like. Typical examples of commercially available information transmission sheets having an ink receiving layer are Canon Inc., trade name Professional Photo Paper, Canon Photographic Paper / Glossy Pro [Platinum Grade], and Glossy Gold; Seiko Epson ( Product name Photo Paper Krispia (high gloss), Photo Paper (Gloss); Nihon Hewlett-Packard Co., Ltd. Product Name Advanced Photo Paper (Gloss); Fuji Film Co., Ltd. Pro; manufactured by Brother Industries, Ltd., trade name: photographic glossy paper BP71G;
Also, plain paper means paper that is not particularly provided with an ink receiving layer, and many different types are commercially available depending on the application. Among commercially available plain papers, for ink-jet recording, double-sided fine plain paper (manufactured by Seiko Epson Corporation); PB PAPER GF-500 (manufactured by Canon Inc.); Multipurpose Paper, All-in-one Printing Paper ( Hewlett Packard). In addition, plain paper copy (PPC) paper or the like whose use is not limited to ink jet recording is also plain paper.

  The colored product of the present invention comprises: (a) the water-soluble azo compound of the present invention; (b) the ink composition of the present invention containing the compound; (c) the ink of the present invention containing the compound and a water-soluble organic solvent. By a composition; means a colored material. The substance to be colored is not particularly limited, and examples thereof include, but are not limited to, the recording material described above. Preferably, the above-mentioned recording material is colored. The coloring method for the substance is not particularly limited, and examples thereof include a printing method such as a dip dyeing method, a textile printing method, and screen printing, and the ink jet recording method of the present invention. The ink jet recording method of the present invention is preferable. Among the colored bodies, a colored body colored by the ink jet recording method of the present invention is preferable.

The water-soluble azo compound of the present invention represented by the above formula (1) is excellent in solubility in water or a water-soluble organic solvent. Moreover, it has the characteristic that the filterability with respect to a membrane filter, for example in the process of manufacturing the ink composition of this invention is favorable. The ink composition of the present invention is very clear on a recording material such as plain paper and an information transmission sheet having an ink receiving layer, has a high saturation and printing density, and is capable of producing a yellow recorded image of an ideal hue. give. Therefore, it is also possible to faithfully reproduce a photographic color image on paper. In addition, the ink composition of the present invention has very good storage stability without solid deposition, physical property change, hue change, etc. after long-term storage.
Even when the ink composition of the present invention is used as an inkjet ink, solid precipitation due to drying of the ink composition in the vicinity of the nozzles is very unlikely to occur, and the ejector (recording head) is not blocked. Further, the ink composition of the present invention uses a continuous ink jet printer, and is used physically even when the ink is recirculated at a relatively long time interval or intermittently used by an on-demand ink jet printer. No change in properties.
Furthermore, the image recorded on the information transmission sheet having the ink receiving layer by the ink composition of the present invention has various fastness properties such as water resistance, moisture resistance, ozone gas resistance, abrasion resistance, and light resistance, The ozone gas property is good, and for this reason, the long-term storage stability of photographic images is also excellent. In addition, compared to conventional inks, it is also excellent in color development properties such as saturation, brightness, and print density on plain paper, and in particular, high saturation.
As described above, the water-soluble azo compound of the present invention represented by the formula (1) and the ink composition of the present invention containing the compound are extremely useful for various recording ink applications, particularly for ink jet recording ink applications. is there.

  EXAMPLES The present invention will be described more specifically with reference to examples. However, the present invention is not limited to the examples. Unless otherwise specified, “part” and “%” in the text are based on mass, and the reaction temperature is the internal temperature. Among the synthesized compounds, those measured for λmax (maximum absorption wavelength) showed measured values in an aqueous solution having a pH of 7-8. Moreover, in each structural formula of the compound obtained in the Example, acidic functional groups, such as a carboxy group and a sulfo group, were described in the form of a free acid.

[(A) Synthesis of Dye]
[Intermediate Synthesis Example 1]
36.2 parts of 5-aminoisophthalic acid was dissolved in 350 parts of water while adjusting the pH to 8 with sodium hydroxide, and then 14.5 parts of sodium nitrite was added. This solution was added dropwise at 0 to 10 ° C. in 440 parts of 5% hydrochloric acid over 30 minutes, followed by stirring at 10 ° C. or less for 1 hour to carry out a diazotization reaction to prepare a diazo reaction liquid.
On the other hand, 63.8 parts of sodium sulfite was dissolved in 400 parts of water and added to the previously prepared diazo reaction solution. To the reaction solution, 118 parts of 35% hydrochloric acid was added, heated to 90 ° C., and stirred for 3 hours. The reaction solution was cooled to 20 ° C., 255 parts of sodium chloride was added and stirred for 30 minutes, and then the precipitated solid was separated by filtration to obtain 88 parts of a wet cake. The wet cake was added to 330 parts of 2-propanol, stirred for 30 minutes, and then the solid cake was filtered and dried. The wet cake was dried with a hot air dryer at 80 ° C., and expressed by the following formula (10). 33 parts of hydrazine compound was obtained.

[Intermediate Synthesis Example 2]
33 parts of the compound represented by the above formula (10) was dissolved in 300 parts of warm water at 60 ° C. while adjusting the pH to 5 with sodium hydroxide, and 35.6 parts of ethyl pivaloyl acetate was added. After the addition, the solution was adjusted to pH 4.5 to 5.0 and the liquid temperature to 60 to 70 ° C. with sodium carbonate, and stirred for 5 hours. After completion of the reaction, the liquid temperature was cooled to 20 ° C., 60 parts of sodium chloride was added to the solution, stirred for 1 hour, and the precipitated solid was separated by filtration to obtain 115 parts of a wet cake. The wet cake was added to 300 parts of water and dissolved by stirring, and then a 25% aqueous sodium hydroxide solution was added to adjust the pH to 6-8. 1000 parts of 2-propanol was added to this aqueous solution, and the wet cake obtained by filtering and separating the precipitated solid was dried with a hot air drier at 80 ° C., whereby compound 42.5 represented by the following formula (11) was obtained. Got a part.

[Example 1]
7.98 parts of 7-aminonaphthalene-1,3-disulfonic acid was dissolved in 80 parts of water while adjusting the pH to 7 with sodium hydroxide, and then 1.13 parts of sodium nitrite was added. This solution was added dropwise at 0 to 10 ° C. over 20 parts of 10% hydrochloric acid over 30 minutes, followed by stirring at 10 ° C. or lower for 1 hour to carry out a diazotization reaction to prepare a diazo reaction solution.
On the other hand, 5 parts of the compound represented by the above formula (11) was dissolved in 45 parts of water while adjusting the pH to 9 with sodium hydroxide, and the previously prepared diazo reaction solution was added dropwise over 1 hour. Stir for hours. During the reaction, the reaction solution was maintained at a pH of 8.0 to 9.0 using a 15% aqueous sodium carbonate solution. After completion of the reaction, 32 parts of sodium chloride was added to the reaction solution, and the precipitated solid was separated by filtration to obtain 20 parts of a wet cake. The wet cake was added to 200 parts of 2-propanol, stirred for 30 minutes, and the solid cake obtained by filtration and separation was dried with a hot air dryer at 80 ° C., and expressed by the following formula (12). 8.1 parts of a sodium salt of the water-soluble azo compound of the present invention (λmax: 413.5 nm, water-soluble substituent / molecular weight = 0.0065) was obtained.

[Example 2]
4.98 parts of 3-aminonaphthalene-1,5-disulfonic acid was dissolved in 80 parts of water while adjusting the pH to 7 with sodium hydroxide, and then 1.13 parts of sodium nitrite was added. This solution was added dropwise at 0 to 10 ° C. over 20 parts of 10% hydrochloric acid over 30 minutes, followed by stirring at 10 ° C. or lower for 1 hour to carry out a diazotization reaction to prepare a diazo reaction solution.
On the other hand, 5 parts of the compound represented by the above formula (11) was dissolved in 45 parts of water while adjusting the pH to 9 with sodium hydroxide, and the previously prepared diazo reaction solution was added dropwise over 1 hour. Stir for hours. During the reaction, the reaction solution was maintained at a pH of 8.0 to 9.0 using a 15% aqueous sodium carbonate solution. After completion of the reaction, 32 parts of sodium chloride was added to the reaction solution, and the precipitated solid was separated by filtration to obtain 20 parts of a wet cake. The wet cake was added to 200 parts of 2-propanol, stirred for 30 minutes, and then the solid cake was separated by filtration. The resulting wet cake was dried with a hot air dryer at 80 ° C., and expressed by the following formula (13). 8.1 parts of a sodium salt of the water-soluble azo compound of the present invention (λmax: 408.5 nm, water-soluble substituent / molecular weight = 0.0065) was obtained.

[Example 3]
6.30 parts of 7-aminonaphthalene-1,3,6-trisulfonic acid was dissolved in 80 parts of water while adjusting the pH to 7 with sodium hydroxide, and then 1.13 parts of sodium nitrite was added. This solution was added dropwise at 0 to 10 ° C. over 20 parts of 10% hydrochloric acid over 30 minutes, followed by stirring at 10 ° C. or lower for 1 hour to carry out a diazotization reaction to prepare a diazo reaction solution.
On the other hand, 5 parts of the compound represented by the above formula (11) was dissolved in 45 parts of water while adjusting the pH to 9 with sodium hydroxide, and the previously prepared diazo reaction solution was added dropwise over 1 hour. Stir for hours. During the reaction, the reaction solution was maintained at a pH of 8.0 to 9.0 using a 15% aqueous sodium carbonate solution. After completion of the reaction, 32 parts of sodium chloride was added to the reaction solution, and the precipitated solid was separated by filtration to obtain 20 parts of a wet cake. This wet cake was added to 200 parts of 2-propanol, stirred for 30 minutes, and then the solid cake obtained by filtration and separation was dried with a hot air dryer at 80 ° C., and expressed by the following formula (14). 9.2 parts of a sodium salt of the water-soluble azo compound of the present invention (λmax: 410.0 nm, water-soluble substituent / molecular weight = 0.0072) was obtained.

[Example 4]
6.30 parts of 7-aminonaphthalene-1,3,5-trisulfonic acid was dissolved in 80 parts of water while adjusting the pH to 7 with sodium hydroxide, and then 1.13 parts of sodium nitrite was added. This solution was added dropwise at 0 to 10 ° C. over 20 parts of 10% hydrochloric acid over 30 minutes, followed by stirring at 10 ° C. or lower for 1 hour to carry out a diazotization reaction to prepare a diazo reaction solution.
On the other hand, 5 parts of the compound represented by the above formula (11) was dissolved in 45 parts of water while adjusting the pH to 9 with sodium hydroxide, and the previously prepared diazo reaction solution was added dropwise over 1 hour. Stir for hours. During the reaction, the reaction solution was maintained at a pH of 8.0 to 9.0 using a 15% aqueous sodium carbonate solution. After completion of the reaction, 32 parts of sodium chloride was added to the reaction solution, and the precipitated solid was separated by filtration to obtain 20 parts of a wet cake. The wet cake was added to 200 parts of 2-propanol, stirred for 30 minutes, and then the solid cake was filtered and dried. The resulting wet cake was dried with a hot air dryer at 80 ° C., and expressed by the following formula (15). 9.2 parts of a sodium salt of the water-soluble azo compound of the present invention (λmax: 408.5 nm, water-soluble substituent / molecular weight = 0.0072) was obtained.

[(B) Preparation of ink]
Using the azo compound of the present invention obtained in Example 1 above [the sodium salt of the compound represented by the formula (12)] as a dye, the composition shown in Table 2 below is mixed to give a solution. An ink composition of the invention was obtained. The obtained ink composition was filtered through a 0.45 μm membrane filter to remove impurities, and a test ink was prepared. The pH of this test ink was in the range of 8.0 to 9.5. In Table 2 below, “surfactant” used was the trade name Surfinol ^RTM 104PG50 manufactured by Nissin Chemical Co., Ltd. The ink prepared using the compound obtained in Example 1 is referred to as Example 5.
In addition, test inks were prepared in the same manner as in Example 5 except that the dyes obtained in Examples 2 to 4 were used in place of the dye obtained in Example 1. These inks are referred to as Examples 6 to 8, respectively.

[Comparative Example 1]
Instead of the compound of the present invention obtained in Example 1, a known pyrazolone yellow dye compound C.I. A comparative ink was prepared in the same manner as in Example 2 except that I (color index) Acid Yellow 17 (compound represented by the following formula (16)) was used. This ink is referred to as Comparative Example 1.
Similarly, instead of the compound of the present invention obtained in Example 1, a known pyrazolone yellow dye compound C.I. A comparative ink was prepared in the same manner as in Example 2, except that I (color index) Acid Yellow 23 (compound represented by the following formula (17)) was used. This ink is referred to as Comparative Example 2.

[(C) Inkjet recording]
The inks prepared in Examples 5 to 8 and Comparative Examples 1 and 2 were recorded on the following three types of glossy paper using an inkjet printer (manufactured by Canon Inc., trade name: PIXUS ^RTM ip7230). Went. At the time of recording, an image pattern was prepared so that six gradation levels of 100%, 85%, 70%, 55%, 40%, and 25% density were obtained, and a halftone recorded matter was obtained. Using the obtained recorded matter as a test piece, the following test was conducted.

Glossy paper 1: manufactured by Canon Inc., trade name: Canon photo paper, platinum grade (PT-201)
Glossy paper 2: manufactured by Seiko Epson Corporation, trade name: photographic paper Krispia Glossy Paper 3: manufactured by Brother Industries, Ltd., trade name, photo glossy paper BP71G

[(D) Colorimetry of recorded images]
Various tests and the evaluation thereof were performed by measuring the color of a test piece using a colorimeter manufactured by X-rite and a trade name of SpectroEye. Colorimetry was performed under the conditions of ANSI A as a density standard, a viewing angle of 2 degrees, and a light source D50.
Various test methods for recorded images and evaluation methods for test results are described below.

[(E) Ozone resistance test]
Each test piece was left for 24 hours at an ozone concentration of 10 ppm, a bath temperature of 23 ° C., and a humidity of 50% RH using an ozone weather meter (model OMS-H manufactured by Suga Test Instruments Co., Ltd.). After the test, using the color measurement system, the print density (Dy) before and after the test was measured to determine the dye residual ratio. The pigment remaining ratio is more excellent when the value is larger. The results are shown in Table 4 below. The dye residual ratio was calculated by the following formula. In the ozone resistance test, the print density (Dy) of the recorded matter before the test was measured, and the dye residual ratio at a gradation part of 70% was obtained. The evaluation criteria are as follows.

Dye remaining rate is 60% or more ...
Dye residual ratio is 40% or more and less than 60% ...
Dye residual ratio is 10% or more and less than 40%.
Dye remaining rate is less than 10% ...

Dye remaining rate = (print density after test / print density before test) × 100 (%)

From the results shown in Table 3, in terms of ozone gas resistance, Examples 5 to 8 showed results superior to Comparative Examples 1 and 2 in glossy paper.
Therefore, it can be seen that the water-soluble azo compound of the present invention and the ink composition of the present invention containing the compound are superior in ozone gas resistance as compared with conventional dyes.

  The water-soluble azo compound of the present invention, which is a yellow dye, and the yellow ink composition of the present invention containing the same provide a recorded image having excellent ozone gas resistance. Therefore, the compound and the ink composition containing the compound are very useful for various recording applications, particularly for inkjet recording applications.

Claims (12)

The water-soluble azo compound or its salt represented by following formula (1).

Wherein R ¹ is a hydrogen atom, halogen atom, carboxy group, carbamoyl group, sulfo group, sulfamoyl group, hydroxy group, amino group, cyano group, phospho group, nitro group, acyl group, (C1-C4) alkyl group. (May be substituted with one or more substituents selected from a hydroxy group, a carboxy group, a carbamoyl group, and a sulfo group), a (C1-C4) alkoxy group (a hydroxy group, a carboxy group, a carbamoyl group, and 1 or 2 or more substituents selected from a sulfo group), (C1-C4) sulfoalkyl group (hydroxy group, carboxy group, carbamoyl group, and 1 or 2 or more selected from a sulfo group) (May be substituted with a substituent), (C1-C4) alkylthio group (hydroxy group, carboxy group, carbamoyl group, and sulfo) 1 or 2 or more substituents selected from a group), (C1-C4) alkylamino group (hydroxy group, carboxy group, carbamoyl group, and sulfo group selected from 1 or 2 or more) Or an acylamino group, n represents an integer of 0 to 4. R ⁵ represents a (C3 to C10) alkyl group.) The water-soluble azo compound for inkjet according to claim 1, wherein R ¹ in the formula (1) is a hydrogen atom. In the said Formula (1), n is 2 or 3, The water-soluble azo compound or its salt of Claim 1 or 2. An ink composition containing the water-soluble azo compound or a salt thereof according to any one of claims 1 to 3. The ink composition according to claim 4, further comprising a water-soluble organic solvent. The ink composition according to claim 4 or 5, which is for inkjet recording. An ink jet recording method in which recording is performed by using the ink composition according to any one of claims 4 to 6 as ink, and ejecting ink droplets of the ink in accordance with a recording signal to adhere to the recording material. The ink jet recording method according to claim 7, wherein the recording material is an information transmission sheet. 9. The ink jet recording method according to claim 8, wherein the information transmission sheet is a sheet having an ink receiving layer containing plain paper or a porous white inorganic substance. (A) the water-soluble azo compound or salt thereof according to any one of claims 1 to 3;
(B) an ink composition containing the water-soluble azo compound or a salt thereof according to any one of claims 1 to 3, or
(C) A colored body colored with any one of the water-soluble azo compound according to any one of claims 1 to 3 or an ink composition containing a salt thereof and a water-soluble organic solvent. A colored body colored by the ink jet recording method according to claim 7. An inkjet printer loaded with a container containing the ink composition according to claim 4.