JP2012031320A - New azo compound, aqueous solution, ink composition, ink for inkjet recording, inkjet recording method, ink cartridge for inkjet recording and inkjet recorded matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink aqueous solution and an ink composition having satisfactory hue as ink for black, which gives a colored image and a colored material having excellent solidity, and further, whose preservation is stable over a long period.SOLUTION: The aqueous solution comprises: (a) an antiseptic agent; and (b) at least one selected from an azo compound expressed by general formula (1) and its salt, wherein the content of the (b) is 1 to 25 mass% (in the formula, A denotes an aryl group or a nitrogen-containing five-membered heterocyclic group; and G denotes a nitrogen atom or the like).

Description

  The present invention relates to an azo compound, an aqueous solution, an ink composition, an ink for ink jet recording, an ink jet recording method, an ink cartridge for ink jet recording, and an ink jet recorded matter.

The ink jet recording method is rapidly spreading and further developing because of its low material cost, high speed recording, low noise during recording, and easy color recording.
Inkjet recording methods include a continuous method in which droplets are continuously ejected and an on-demand method in which droplets are ejected in accordance with image information signals. There are a method for ejecting droplets, a method for generating bubbles in ink by discharging heat, a method for discharging droplets, a method using ultrasonic waves, and a method for attracting and discharging droplets by electrostatic force. As the ink for ink jet recording, water-based ink, oil-based ink, or solid (melted type) ink is used.

  For the colorant used in such ink for ink jet recording, the solvent has good solubility or dispersibility, high density recording is possible, hue is good, light, heat, environment It is robust against active gases (NOx, oxidizing gases such as ozone, SOx, etc.), has excellent fastness to water and chemicals, and has good fixability to image receiving materials and is difficult to bleed. The ink is required to have excellent storage stability, no toxicity, high purity, and availability at low cost. However, it is extremely difficult to search for colorants that meet these requirements at a high level.

  In particular, an ink having a good black hue, robust against light, humidity and heat, a high molar extinction coefficient, high character quality in document printing, and porous white inorganic pigment particles When printing on an image receiving material having a receiving layer, it is strongly desired to be robust against oxidizing gases such as ozone in the environment.

  Therefore, the dyes used in each of the above applications need to have the following properties in common. That is, it has favorable absorption characteristics in terms of color reproducibility, fastness under the environmental conditions used, for example, light resistance, heat resistance, moisture resistance, resistance to oxidizing gases such as ozone, and other chemical fastness such as sulfurous acid gas For example, the property is good and the molar extinction coefficient is large.

  Conventionally, disazo dyes and trisazo dyes have been generally used as black dyes. Non-heterocyclic compounds such as phenol, naphthol, naphthylamine, and aniline are widely used as raw materials for these disazo dyes and trisazo dyes. As the disazo dyes obtained from these raw materials, the dyes disclosed in Patent Document 1, Patent Document 2, and the like are known, but all have the problem that light fastness is inferior, and oxidizing properties such as ozone. Fastness to gas is very poor.

  As a result of intensive studies, the present inventors have moved away from conventional raw materials such as phenol, naphthol, naphthylamine, and aniline in order to develop a colorant that is robust against oxidizing gases such as light and ozone. It came to the idea of using a ring compound as a raw material. So far, disazo dyes and trisazo dyes containing two or more hetero rings have been described in Patent Document 3, Patent Document 4, Patent Document 5, etc., but these dyes are all used for dyeing fibers. It is a so-called dye that has been developed, and has the performance required in the present invention, that is, whether it has favorable absorption characteristics for color reproduction, and fastness (for example, light resistance, heat resistance, moisture resistance) under the used environmental conditions. In particular, there is no disclosure on the properties, particularly resistance to oxidizing gases such as ozone, which is a problem in inkjet image formation, and other chemical fastness properties such as sulfurous acid gas, and any structure is optimal for image formation of the present invention. It is completely unknown whether there is any. In addition, the water-soluble dye of Patent Document 5, which describes a water-soluble disazo dye containing two or more heterocycles, has only two water-soluble groups, so it has low solubility in water. It was not suitable for inkjet applications.

  Patent Document 6 describes a water-soluble disazo dye having an ionic hydrophilic group. When the water-soluble disazo dye was converted into an ink, the dissolution stability in the ink was improved, but the dye stability (the dye was decomposed) in the ink was insufficient, and a great improvement was required.

  Patent Document 7 discloses that an association effect, a hydrophobic field effect, and a steric effect of a dye structure are controlled by introducing a specific substituent into a specific substitution position of a water-soluble disazo dye having an ionic hydrophilic group. However, the stability of the dye in the ink (decomposition of the dye) has been greatly improved. However, when the printed image is formed using the ink using the dye due to the enhanced association of the dye, the image quality is remarkably improved. Decrease (more specifically, bronze gloss occurs).

  When a recorded image having a high optical density is formed, there is a problem that a so-called bronze phenomenon occurs in which a dye crystal precipitates on the surface of the recording material as it dries, and the recorded image reflects light and emits a metallic luster. there were.

  This phenomenon is caused by increasing the association (aggregation) of the dye by reducing the water solubility of the dye to improve water resistance or by introducing an amino group of a hydrogen bond group into the dye structure. This is likely to occur. Since the light is reflected by the occurrence of the bronze phenomenon, not only the optical density of the recorded image is lowered, but also the hue of the recorded image is greatly different from the desired one. This is one of the important performance characteristics.

  As a method for suppressing the bronze phenomenon, a method of adding a specific nitrogen-containing compound (for example, JP-A Nos. 55-120676, 62-119280, 64-6072, and No. 1-152176) JP-A-2-41369, JP-A-5-125311, JP-A-6-25575, JP-A-6-128515, JP-A-6-228476, JP-A-6-228383, JP-A-6-248212, JP-A-7-228810, JP-A-7-268261, JP-A-8-259865, JP-A-9-12944, JP-A-9-12946, JP-A-9-12949, JP-A-10-36735 ), A method of adding a specific titanium compound (JP-A-8-337745) and the like have been known so far. However, even though the addition of these additives can suppress the occurrence of the bronze phenomenon, there is a concern that the additives may reduce the performance of the ink and the quality of the recorded image. For example, when alkanolamine is added to the ink, the bronzing phenomenon can be prevented, but even if it is added in a small amount, the pH of the ink becomes 11 or more. Japanese Patent Application Laid-Open No. 8-259865 describes that safety when touched is poor, and print quality and water resistance of recorded images are also lowered.

  In addition, as an example of improving the performance of the ink-jet ink by an additive, JP-A-5-339532 and JP-A-2001-254040 disclose that a counter cation is a lithium ion, a quaternary ammonium ion, or a quaternary phosphonium ion. It is described that by adding an anionic additive other than the dye, a clogging preventing effect due to improved solubility can be obtained even when the counter ion of the dye is not these ions. On the other hand, Japanese Patent Application Laid-Open No. 7-26178 describes that the addition of an alkali metal compound to the ink suppresses the formation of dye aggregates and does not increase the viscosity of the ink. In JP 36735, it is pointed out that although there is an improvement effect in a short period, there is a problem in storage stability when stored for a long period.

  In this way, various effects can be obtained by using additives, but it is difficult to use while maintaining various performances, especially when it is necessary to consider the solubility and association of the dye. It can be seen that it is difficult to select the type and quantity of objects. Further, when an ionic additive is used, the influence of the counter ion must be taken into consideration. Therefore, it can be said that it is preferable to introduce an essential bronzing suppression method that does not depend on additives.

  Attempts have been actively made to improve various performances required for inkjet inks by changing the counter cation of the ionic hydrophilic group of the metal phthalocyanine compound. For example, JP-A-5-339532, JP-A-6-16982, JP-A-6-248212, JP-A-6-322286, JP-A-7-138511, JP-A-10-130517, etc. Is mentioned.

As examples in which lithium ions are preferred as the counter cation of the ionic hydrophilic group of the metal phthalocyanine dye, JP-A-57-202358, JP-A-63-81179, JP-A-63-317568 Publication, Japanese Patent No. 2581769, is like Japanese Patent No. 3163176, these high concentrations of ink, has been described to be effective storage stability, etc. ejection stability. On the other hand, Japanese Patent Application Laid-Open No. 7-82499 describes that when the counter cation is lithium ion, the water resistance of the recorded image is lowered because the water solubility of the dye is high, which is not preferable. Therefore, in order to satisfy the performance required for the ink-jet ink, it can be understood that it is difficult to cope with it simply by changing the salt.

Conventionally, disazo dyes or trisazo dyes have been used as black pigments, but these dyes alone often lack blue to green light absorption and often do not provide a good black tone. In general, a dye for color correction that absorbs blue to green light is used in combination. As such a correction dye, for example, dyes described in Patent Document 8 and Patent Document 9 have been proposed, and black tone adjustment ability, color development, fastness, ink storage stability, water resistance, nozzle resistance, and the like. Improvements such as clogging have been attempted.
However, the conventionally proposed color correction dyes have a problem of lack of black tone adjustment ability, such as the necessity of adding a large amount because the absorption is too short, and the need for another color correction dye. I had it.

  Dyes that can absorb blue to green light are generally known, but their fastness is inferior, so the hue changes greatly upon exposure to light, heat, and active gases in the environment, and the fixability is insufficient. For this reason, almost all of the phenomena such as yellowing of the outline portion under high humidity conditions occur, and further improvement is necessary.

In view of these drawbacks, Patent Document 10 describes a black ink composition comprising a triazine dye having a maximum absorption spectrum of 435 nm in a water solvent as a color correction dye, and a black dye. .
Further, Patent Documents 11 and 12 propose that a substituent such as an ionic hydrophilic group be introduced into the dye mother nucleus and the triazine ring in order to increase water solubility.

  However, a general black dye has a maximum absorption of 570 to 620 nm, and even when the color correction dye is used, a suitable black tone cannot be obtained in consideration of a complementary color relationship important for black tone adjustment. It is clear.

  Based on this, Patent Document 13 proposes that a suitable black tone can be obtained by including a dye having an absorption maximum in the visible region absorption spectrum of 440 to 540 nm in an aqueous solvent as a color correction dye. Yes.

  However, the compound examples described in the patent document have problems such as lack of storage stability as ink, or color change (short wavelength) under high humidity and high temperature after printing on ink jet paper. It is hard to say that it still has sufficient performance.

In Patent Documents 14 and 15, benzene rings or naphthalene rings and heterocyclic condensed rings are used as black dyes to give black recorded images with excellent image fastness, particularly light resistance and ozone gas resistance. An untargeted tris or tetrakisazo compound linked by a group is described.
However, the compound examples described in the patent document have problems such as lack of storage stability as ink, or color change (short wavelength) under high humidity and high temperature after printing on ink jet paper. It is hard to say that it still has sufficient performance.

  Thus, the present condition is that the ink which satisfy | fills various performances calculated | required by the water-soluble inkjet ink simultaneously is not yet found.

European Patent No. 0761771 Japanese Patent No. 2716541 German Patent No. 2743097 JP 59-133259 A JP-A-52-76331 JP 2003-306623 A JP 2005-139427 A JP-A-9-255906 Japanese Patent No. 3178200 JP 2002-332426 A JP 2005-298636 A International Publication No. 06/001274 JP 2005-344071 A International Publication No. 07/077931 JP 2009-132794 A

  The object of the present invention is to provide a colored image or coloring material that has a good hue as a black ink, has excellent fastness properties, and has little change in physical properties even when stored for a long period of time. Providing an ink and an aqueous solution and an ink composition. It is another object of the present invention to provide ink for printing such as inkjet and writing ink, and also provide a method image forming method (image quality lowering improvement method) that does not involve deterioration in image quality of the formed image.

  The present inventors have studied in detail with the aim of a dye that has a good hue and does not cause bronzing, has high light fastness and gas fastness (especially ozone gas), and is stable even after long-term storage in ink. However, the present inventors have found that the above problems can be solved by an asymmetric azo compound in which an aromatic hydrocarbon ring or an aromatic heterocyclic group having a substituent, a heterocycle, and a heterocondensed ring are bonded with an azo group. It came to be completed. More specifically, an asymmetric azo compound in which a hetero condensed ring having a specific substituent at a specific substitution position, a specific hetero ring, and a specific aromatic hydrocarbon ring are bonded via an azo group is excellent as a dye. General formula (1) of the present invention having (1) a specific spectral absorption curve and (2) a specific dye structure (introducing a specific number of substituents at a specific substitution position). Azo dyes represented by general formula (2) of the present invention, particularly the azo dyes represented by general formula (3) or general formula (4) of the present invention. The inventors have found that this can be solved, and have completed the present invention. That is, the object of the present invention is achieved by the following means.

[1] It contains (a) an antiseptic and (b) at least one azo compound represented by the following general formula (1) or a salt thereof, and the content of (b) is 1% by mass to 25% by mass. % Aqueous solution.

(In General Formula (1), A represents an aryl group or a nitrogen-containing 5-membered heterocyclic group. G represents a nitrogen atom or —C (R ₂ ) ═. R ₂ represents a hydrogen atom or a sulfo group. group, a carboxy group, _.Y 2, _{Y 3} and _{Y 4} representing a substituted or unsubstituted carbamoyl group, or a cyano group independently, _.Y 2, _{Y 3} represents a hydrogen atom, or a monovalent substituent And Y ₄ may combine with each other to form a ring, M represents a hydrogen atom or a monovalent counter cation, and n represents an integer of 0, 1 or 2.)

[2] The aqueous solution according to [1], further comprising (c) a pH adjuster.

[3] The aqueous solution according to [1] or [2], wherein the azo compound represented by the general formula (1) is an azo compound represented by the following general formula (2).

(In General Formula (2), G represents a nitrogen atom or —C (R ₂ ) ═. R ₂ represents a hydrogen atom, a sulfo group, a carboxy group, a substituted or unsubstituted carbamoyl group, or a cyano group. R ₃ represents a monovalent substituent, A represents an aryl group or a nitrogen-containing 5-membered heterocyclic group, M represents a hydrogen atom or a monovalent counter cation, and n represents 0. Represents an integer of 1 or 2.)

[4] Any of the above [1] to [3], wherein the azo compound represented by the general formula (1) or (2) is an azo compound represented by the following general formula (3) The aqueous solution according to claim 1.

(In General Formula (3), R ₃ represents a monovalent substituent. X ₁ , X ₂ , X ₃ , X ₄ , and X ₅ each independently represents a hydrogen atom or a monovalent substituent. M represents a hydrogen atom or a monovalent counter cation, and n represents an integer of 0, 1 or 2.)

[5] Any of the above [1] to [3], wherein the azo compound represented by the general formula (1) or (2) is an azo compound represented by the following general formula (4): The aqueous solution according to claim 1.

(In General Formula (4), R ₃ represents a monovalent substituent. X ₁ , X ₂ , X ₃ , X ₄ , and X ₅ are each independently a hydrogen atom or a monovalent substituent. M represents a hydrogen atom or a monovalent counter cation, and n represents an integer of 0, 1 or 2.)

[6] Any one of the above-mentioned [1] to [5], wherein the azo compound represented by the general formulas (1) to (4) has at least three or more ionic hydrophilic groups. The aqueous solution described in 1.

[7] The aqueous solution according to any one of [1] to [6] above, wherein the pH is 7.0 to 9.0.

[8] An ink composition comprising the aqueous solution according to any one of [1] to [7].

[9] An inkjet recording ink comprising the aqueous solution according to any one of [1] to [7].

[10] An inkjet recording method comprising forming a colored image on a recording material using the inkjet recording ink according to [9].

[11] An ink cartridge for ink jet recording filled with the ink for ink jet recording described in [9].

[12] An ink jet recorded matter in which a color image is formed on a recording material using the ink for ink jet recording described in [9].

[13] An azo compound represented by the following general formula (1) or a salt thereof.

(In General Formula (1), A represents an aryl group or a nitrogen-containing 5-membered heterocyclic group. G represents a nitrogen atom or —C (R ₂ ) ═. R ₂ represents a hydrogen atom, a sulfo group, Y ₂ , Y ₃ and Y ₄ each independently represents a hydrogen atom or a monovalent substituent, Y ₂ , Y ₃ and Y each representing a carboxy group, a substituted or unsubstituted carbamoyl group or a cyano group. ₄ may combine with each other to form a ring, M represents a hydrogen atom or a monovalent counter cation, and n represents an integer of 0, 1 or 2.)

[14] The azo compound or the salt thereof according to [13], wherein the azo compound represented by the general formula (1) is an azo compound represented by the following general formula (3).

(In General Formula (3), R ₃ represents a monovalent substituent. X ₁ , X ₂ , X ₃ , X ₄ , and X ₅ each independently represents a hydrogen atom or a monovalent substituent. M represents a hydrogen atom or a monovalent counter cation, and n represents an integer of 0, 1 or 2.)

[15] The azo compound or the salt thereof according to [13], wherein the azo compound represented by the general formula (1) is an azo compound represented by the following general formula (4).

(In General Formula (4), R ₃ represents a monovalent substituent. X ₁ , X ₂ , X ₃ , X ₄ , and X ₅ are each independently a hydrogen atom or a monovalent substituent. M represents a hydrogen atom or a monovalent counter cation, and n represents an integer of 0, 1 or 2.)

  The azo compound of the present invention can be used as a pigment and is useful for ink. The ink using the azo compound of the present invention can give a colored image or coloring material excellent in ink storage stability and excellent in hue and fastness. In particular, the ink for ink jet recording and the ink jet recording method using the above-described ink of the present invention have high ink stability, good hue, and fastness to light and environmental active gas, particularly ozone gas. A high image can be formed, and in particular, deterioration in image quality of a printed image can be improved (bronze gloss suppression).

The present invention is described in detail below.
First, in the present invention, the substituent group A ′, the substituent group J, the ionic hydrophilic group, and Hammett's substituent constant σp value are defined.

(Substituent group A ′)
C1-C12 linear or branched alkyl group, C7-C18 linear or branched aralkyl group, C2-C12 linear or branched alkenyl group, C2-C12 linear Or a branched alkynyl group, a C3-C12 cycloalkyl group, a C3-C12 cycloalkenyl group (for example, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl) , T-butyl, 2-ethylhexyl, 2-methylsulfonylethyl, 3-phenoxypropyl, trifluoromethyl, cyclopentyl), halogen atom (for example, chlorine atom, bromine atom), aryl group (for example, phenyl, 4-t- Butylphenyl, 2,4-di-t-amylphenyl), heterocyclic groups (eg imidazolyl, pyrazolyl, triazolyl, 2-furyl, 2-thiol) Nyl, 2-pyrimidinyl, 2-benzothiazolyl), cyano group, hydroxyl group, nitro group, carboxy group, amino group, alkyloxy group (for example, methoxy, ethoxy, 2-methoxyethoxy, 2-methylsulfonylethoxy), aryloxy Groups (for example, phenoxy, 2-methylphenoxy, 4-t-butylphenoxy, 3-nitrophenoxy, 3-t-butyloxycarbonylphenoxy, 3-methoxycarbonylphenyloxy, acylamino groups (for example, acetamide, benzamide, 4- (3-t-butyl-4-hydroxyphenoxy) butanamide), alkylamino groups (eg methylamino, butylamino, diethylamino, methylbutylamino), arylamino groups (eg phenylamino, 2-chloroanilino) Ureido group (for example, phenylureido, methylureido, N, N-dibutylureido), sulfamoylamino group (for example, N, N-dipropylsulfamoylamino), alkylthio group (for example, methylthio, octylthio, 2- Phenoxyethylthio), arylthio groups (eg phenylthio, 2-butoxy-5-t-octylphenylthio, 2-carboxyphenylthio), alkyloxycarbonylamino groups (eg methoxycarbonylamino), alkylsulfonylamino groups and aryls A sulfonylamino group (eg, methylsulfonylamino, phenylsulfonylamino, p-toluenesulfonylamino), a carbamoyl group (eg, N-ethylcarbamoyl, N, N-dibutylcarbamoyl), a sulfamoyl group (eg, For example, N-ethylsulfamoyl, N, N-dipropylsulfamoyl, N-phenylsulfamoyl), sulfonyl group (for example, methylsulfonyl, octylsulfonyl, phenylsulfonyl, p-toluenesulfonyl), alkyloxycarbonyl group (For example, methoxycarbonyl, butyloxycarbonyl), heterocyclic oxy group (for example, 1-phenyltetrazol-5-oxy, 2-tetrahydropyranyloxy), azo group (for example, phenylazo, 4-methoxyphenylazo, 4- Pivaloylaminophenylazo, 2-hydroxy-4-propanoylphenylazo), acyloxy group (for example, acetoxy), carbamoyloxy group (for example, N-methylcarbamoyloxy, N-phenylcarbamoyloxy), silyloxy group For example, trimethylsilyloxy, dibutylmethylsilyloxy), aryloxycarbonylamino group (for example, phenoxycarbonylamino), imide group (for example, N-succinimide, N-phthalimide), heterocyclic thio group (for example, 2-benzothiazolyl) Ruthio, 2,4-di-phenoxy-1,3,5-triazole-6-thio, 2-pyridylthio), sulfinyl group (eg 3-phenoxypropylsulfinyl), phosphonyl group (eg phenoxyphosphonyl, octyloxy) Phosphonyl, phenylphosphonyl), aryloxycarbonyl group (for example, phenoxycarbonyl), acyl group (for example, acetyl, 3-phenylpropanoyl, benzoyl), ionic hydrophilic group (carboxyl group, sulfo group, etc.) Be These substituents may be further substituted, and examples of the further substituent include groups selected from the substituent group A ′ described above.

(Substituent group J)
For example, halogen atom, alkyl group, aralkyl group, alkenyl group, alkynyl group, aryl group, heterocyclic group, cyano group, hydroxyl group, nitro group, alkoxy group, aryloxy group, silyloxy group, heterocyclic oxy group, acyloxy group , Carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, amino group, acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfamoylamino group, alkyl or arylsulfonylamino group , Mercapto group, alkylthio group, arylthio group, heterocyclic thio group, sulfamoyl group, alkyl or arylsulfinyl group, alkyl or arylsulfonyl group, acyl group, aryloxycarboni Examples include groups, alkoxycarbonyl groups, carbamoyl groups, aryl or heterocyclic azo groups, imide groups, phosphino groups, phosphinyl groups, phosphinyloxy groups, phosphinylamino groups, silyl groups, and ionic hydrophilic groups. . These substituents may be further substituted, and examples of the further substituent include a group selected from the substituent group J described above.

  More specifically, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  Examples of the alkyl group include linear, branched, and cyclic substituted or unsubstituted alkyl groups, and include cycloalkyl groups, bicycloalkyl groups, and tricyclo structures having many ring structures. An alkyl group (for example, an alkyl group of an alkoxy group or an alkylthio group) in a substituent described below also represents such an alkyl group. Specifically, the alkyl group is preferably an alkyl group having 1 to 30 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an iso i-propyl group, a t-butyl group, an n-octyl group, An eicosyl group, a 2-chloroethyl group, a 2-cyanoethyl group, a 2-ethylhexyl group, and the like. The cycloalkyl group is preferably a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, such as a cyclohexyl group. , Cyclopentyl group, 4-n-dodecylcyclohexyl group, etc., and the bicycloalkyl group is preferably a substituted or unsubstituted bicycloalkyl group having 5 to 30 carbon atoms, that is, a bicycloalkane having 5 to 30 carbon atoms. Monovalent groups in which one hydrogen atom has been removed from, for example, a bicyclo [1,2,2] heptan-2-yl group, Black [2,2,2] octan-3-yl group.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

(Ionic hydrophilic group)
A sulfo group, a carboxyl group, a thiocarboxyl group, a sulfino group, a phosphono group, a dihydroxyphosphino group and the like can be mentioned. Particularly preferred are a sulfo group and a carboxyl group. The carboxyl group, phosphono group, and sulfo group may be in the form of a salt. Examples of counter ions that form a salt include ammonium ions, alkali metal ions (eg, lithium ions, sodium ions, potassium ions) and organic ions. Cation (eg, tetramethylammonium ion, tetramethylguanidinium ion, tetramethylphosphonium) is included, lithium salt, sodium salt, potassium salt, ammonium salt is preferable, lithium salt or mixed salt containing lithium salt as a main component Are more preferred, and lithium salts are most preferred.

The counter cation of the ionic hydrophilic group contained in the azo compound of the present invention contains lithium ions as a main component. The counter cations may not be all lithium ions, but the lithium ion concentration in each ink composition is preferably 50% by mass or more based on the total counter ions in each ink composition. Preferably it is 75 mass% or more, More preferably, it is 80 mass% or more, Most preferably, it is 95 mass% or more.
Under such conditions, hydrogen ions, alkali metal ions (for example, sodium ions, potassium ions), alkaline earth metal ions (for example, magnesium ions, calcium ions, etc.), quaternary ammonium ions, quaternary phosphoniums Ions, sulfonium ions, and the like can be included as counter cations.

Regarding the types and ratios of the counterions of the above-mentioned colorants, the Chemical Society of Japan “New Experimental Chemistry Course 9 Analytical Chemistry” (1977 Maruzen) and the Chemical Society of Japan “4th edition Experimental Chemistry Course 15 Analysis” (1991 Maruzen) ) Describes various theories about analysis methods and elements, so that analysis methods can be selected, analyzed and quantified by referring to them. In particular, it is easy to determine by an analytical method such as ion chromatography, atomic absorption, inductively coupled plasma emission spectrometry (ICP).
As a method for obtaining the colorant of the present invention in which the counter cation contains lithium ions, any method may be used. For example, (1) a method of converting a counter cation from another cation to lithium ions using an ion exchange resin, (2) a method of acid precipitation or salting out from a system containing lithium ions, and (3) a counter cation of lithium ions (4) A method of introducing an ionic hydrophilic group by functional group conversion of each colorant using a reactive agent whose counter cation is a lithium ion. (5) A compound in which the counter cation of the ionic hydrophilic group in the colorant is a silver ion is synthesized, and this is reacted with a lithium halide solution to remove the precipitated silver halide, thereby converting the counter cation to a lithium ion. The method of making it.

The ionic hydrophilic group in each colorant may be any as long as it is an ionic dissociation group. Preferred ionic hydrophilic groups include a sulfo group (may be a salt), a carboxyl group (may be a salt), a hydroxyl group (may be a salt), a phosphono group (may be a salt), a quaternary ammonium group, and an acylsulfamoyl group. (May be a salt), a sulfonylcarbamoyl group (may be a salt), a sulfonylsulfamoyl group (may be a salt), and the like.
A sulfo group, a carboxyl group, or a hydroxyl group (including salts thereof) is preferable. When the ionic hydrophilic group is a salt, a preferable counter cation is lithium or a mixed salt of an alkali metal (for example, sodium, potassium), ammonium, and an organic cation (for example, pyridinium, tetramethylammonium, guanidinium) based on lithium. Among them, lithium or an alkali metal mixed salt containing lithium as a main component is preferable, and a lithium salt of a sulfo group and a lithium salt of a carboxy group are particularly preferable.

(Hammett's substituent constant σp value)
Hammett's substituent constant σp value used in this specification will be described.
Hammett's rule is a method described in 1935 in order to quantitatively discuss the effect of substituents on the reaction or equilibrium of benzene derivatives. P. A rule of thumb proposed by Hammett, which is widely accepted today. Substituent constants determined by Hammett's rule include a σp value and a σm value, and these values can be found in many general books. A. Dean, “Lange's Handbook of Chemistry”, 12th edition, 1979 (Mc Graw-Hill) and “Chemicals” special edition, 122, 96-103, 1979 (Nankodo). In the present invention, each substituent is limited or explained by Hammett's substituent constant σp, but this means that it is limited to only a substituent having a value known in the literature, which can be found in the above-mentioned book. Needless to say, even if the value is unknown, it includes a substituent that would be included in the range when measured based on Hammett's rule. Although the compound concerning this invention is not a benzene derivative, (sigma) p value is used as a scale which shows the electronic effect of a substituent irrespective of a substitution position. In the present invention, the σp value will be used in this sense.

  In the present invention, when the compound is a salt, the salt is dissociated into ions in the ink, but is expressed as “contains a salt” for convenience.

<Aqueous solution>
The aqueous solution of the present invention contains (a) a preservative and (b) at least one azo compound represented by the general formula (1) or a salt thereof, and the content of (b) is 1% by mass to 25% by mass. The content of (b) is preferably 3% by mass to 15% by mass, and more preferably 5% by mass to 12% by mass. By setting the content of (b) in the above range, there is an effect that the storage stability of the aqueous solution is good and the preparation of the water-soluble ink for inkjet is easy.
The aqueous solution of the present invention preferably has a pH of 7.0 to 9.0, more preferably 7.5 to 8.5. By adjusting the pH to the above range, there are the effects that high solution stability of the azo compound in the aqueous solution can be imparted and the preparation of the water-soluble ink for inkjet is easy.
The aqueous solution of the present invention may be referred to as “ink stock solution”.

  Hereinafter, the present invention will be described in more detail. First, the groups and substituents of the general formula in the present invention will be described.

[(A) Preservative]
In the aqueous solution of the present invention, generation of insoluble matter due to decay may be a problem. In order to prevent this, it is preferable to add a preservative to the aqueous solution.
Various preservatives that can be used in the present invention can be used.
Examples of the preservative include inorganic preservatives (such as silver ion-containing substances) and salts containing heavy metal ions. Organic preservatives include quaternary ammonium salts (tetrabutylammonium chloride, cetylpyridinium chloride, benzyltrimethylammonium chloride, etc.), phenol derivatives (phenol, cresol, butylphenol, xylenol, bisphenol, etc.), phenoxyether derivatives (phenoxyethanol) Etc.), heterocyclic compounds (benzotriazole, proxel, 1,2-benzisothiazolin-3-one, etc.), acid amides, carbamic acid, carbamates, amidine / guanidine, pyridines (sodium pyridinethione- 1-oxide, etc.), diazines, triazines, pyrrole / imidazoles, oxazoles / oxazines, thiazoles / thiadiazines, thioureas, thiosemicarbazides , Dithiocarbamates, sulfides, sulfoxides, sulfones, sulfamides, antibiotics (penicillin, tetracycline, etc.), sodium dehydroacetate, sodium benzoate, ethyl p-hydroxybenzoate, and salts thereof Can be used. In addition, as the antiseptic, those described in the antibacterial and microscopic handbook (Technical Hall: 1986), the antibacterial and antifungal encyclopedia (edited by the Japanese Society for Antibacterial and Antifungal Society), etc. can be used.
As a preservative, a phenol derivative and a heterocyclic compound are preferable, a heterocyclic compound is more preferable, and a heterocyclic compound (Proxel XL-II) is still more preferable.
One or more preservatives can be added to the aqueous solution in combination.
Various compounds such as those having an oil-soluble structure and a water-soluble structure can be used, but a water-soluble compound is preferable.
Among these, it is preferable that at least one preservative is a heterocyclic compound.
In the present invention, when two or more kinds of preservatives are used in combination, the effect of the present invention is more satisfactorily exhibited. For example, the combination of a heterocyclic compound and an antibiotic, the combination of a heterocyclic compound and a phenol derivative, etc. are mentioned preferably. The content ratio in the case of combining two kinds of preservatives is not particularly limited, but a range of preservative A / preservative B = 0.01 to 100 (mass ratio) is preferable.
Although the addition amount of the preservative to the aqueous solution can be used within a wide range, it is preferably 0.001 to 10% by mass, more preferably 0.1 to 5% by mass. By setting the content of the preservative within the above range, there is an effect of suppressing the growth of bacteria in the aqueous solution.

[(B) Azo compound represented by formula (1)]
The azo compound represented by the general formula (1) (hereinafter sometimes referred to as “compound represented by the general formula (1)”) will be described.

(In General Formula (1), A represents an aryl group or a nitrogen-containing 5-membered heterocyclic group. G represents a nitrogen atom or —C (R ₂ ) ═. R ₂ represents a hydrogen atom or a sulfo group. group, a carboxy group, _.Y 2, _{Y 3} and _{Y 4} representing a substituted or unsubstituted carbamoyl group, or a cyano group independently, _.Y 2, _{Y 3} represents a hydrogen atom, or a monovalent substituent And Y ₄ may combine with each other to form a ring, M represents a hydrogen atom or a monovalent counter cation, and n represents 0, 1 or 2.)

G in the general formula (1) represents a nitrogen atom or —C (R ₂ ) ═. R ₂ represents a hydrogen atom, a sulfo group, a carboxy group, a substituted or unsubstituted carbamoyl group, or a cyano group. When the carbamoyl group has a substituent, the substituent is an alkyl group (methyl group, ethyl group), An aryl group (phenyl group) can be mentioned.

Y ₂ , Y ₃ , and Y ₄ each independently represent a hydrogen atom or a monovalent substituent. Examples of the substituent in the case where Y ₂ , Y ₃ , and Y ₄ represent a substituent can include the substituent group J independently.
In General Formula (1), Y ₂ , Y ₃ , and Y ₄ are each independently a hydrogen atom, an ionic hydrophilic group, a substituted or unsubstituted carbamoyl group, a substituted or unsubstituted sulfamoyl group, substituted or unsubstituted An alkylsulfonylamino group, a substituted or unsubstituted arylsulfonylamino group, and an acylamino group, preferably a hydrogen atom, an alkylsulfonylamino group having an ionic hydrophilic group as a substituent, and an ionic hydrophilic group as a substituent. More preferably an arylsulfonylamino group having an ionic hydrophilic group as a substituent, and an arylamino group having an ionic hydrophilic group as a substituent. Particularly preferred is an acylamino group as a substituent.
When the carbamoyl group, sulfamoyl group, alkylsulfonylamino group, arylsulfonylamino group, and acylamino group represented by Y ₂ , Y ₃ , and Y ₄ have a substituent, each independently represents an ionic hydrophilic group. (For example, —CO ₂ M, —SO ₃ M: M is a monovalent counter cation) is more preferable.
Y ₂ , Y ₃ , and Y ₄ may be bonded to each other to form a ring, and Y ₂ , Y ₃ , and Y ₄ may be bonded to each other to form, for example, a benzene ring or a naphthalene ring. It is recommended that it be a benzene ring.
Y ₂ , Y ₃ , and Y ₄ may further have a substituent, and examples of the further substituent include an aryl group and a heterocyclic group which may have a hydroxyl group or an ionic hydrophilic group. Can be mentioned.

A represents an aryl group, a monocyclic ring or a condensed heterocyclic group. The aryl group includes a substituted or unsubstituted aryl group. More specifically, an aryl group having substituent group J can be mentioned.
The aryl group represented by A is preferably a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and more preferably a substituted or unsubstituted phenyl group. Examples of the substituent include the groups described in the above-mentioned substituent group, and the ionic hydrophilic group or the electron-withdrawing group having a Hammett's σp value of 0.3 or more is preferable.

The heterocyclic group represented by A includes a substituted or unsubstituted heterocyclic group. The heterocyclic group represented by A is preferably a monovalent group obtained by removing one hydrogen atom from a 5- or 6-membered substituted or unsubstituted aromatic or non-aromatic heterocyclic compound. 3-30 5- or 6-membered aromatic heterocyclic groups are more preferred. Examples of the substituent include the groups described in the above-mentioned Substituent J section. As an example of the heterocyclic group, a nitrogen-containing 5-membered heterocyclic group can be represented by any substitution position without limitation: pyrrole ring, pyrazole ring, imidazole ring, triazole ring, thiazole ring, isothiazole ring, thiadiazole ring Is mentioned.
Examples of the nitrogen-containing 6-membered heterocyclic group include a pyridine ring, a pyrazone ring, a pyridazine ring, a pyrimidine ring, and a triazine ring when the substitution position is not limited.

  A is preferably an aryl group having a substituent, more preferably an ionic hydrophilic group or an aryl group having a Hammett's σp value of 0.3 or more, and an ionic hydrophilic group. A phenyl group having an electron-attracting group having a group or Hammett σp value of 0.3 or more is more preferable.

As the ionic hydrophilic group in the general formula (1), —SO ₃ M ₁ or —CO ₂ M ₁ is preferable, —SO ₃ M ₁ is more preferable, and —SO ₃ Li is particularly preferable.

M ₁ and M each independently represent a hydrogen atom or a monovalent counter cation. Examples of the monovalent counter cation include ammonium ion, alkali metal ion (eg, lithium ion, sodium ion, potassium ion) and organic. Examples include cations (eg, tetramethylammonium ion, tetramethylguanidinium ion, tetramethylphosphonium), and lithium salts, sodium salts, potassium salts, and ammonium salts are preferable, and lithium salts or mixed salts mainly composed of lithium salts Are more preferred, and lithium salts are most preferred.

  A particularly preferable combination as the compound represented by the general formula (1) includes the following (A) to (E).

(A) G represents a nitrogen atom or —C (R ₂ ) ═, and preferably —C (R ₂ ) ═. R ₂ represents a hydrogen atom, a sulfo group, a carboxy group, a substituted or unsubstituted carbamoyl group, or a cyano group, preferably a carbamoyl group (—CONH ₂ group) or a cyano group, and preferably a cyano group. More preferred.

(B) A is preferably an aryl group having a substituent, more preferably an ionic hydrophilic group or an aryl group having an electron-withdrawing group having a Hammett's σp value of 0.3 or more. More preferably, it is a phenyl group having two hydrophilic hydrophilic groups.

(C) Y ₂ , Y ₃ and Y ₄ are each independently a hydrogen atom, an ionic hydrophilic group, a substituted or unsubstituted carbamoyl group, a substituted or unsubstituted sulfamoyl group, a substituted or unsubstituted alkylsulfonylamino Group, substituted or unsubstituted arylsulfonylamino group, acylamino group, hydrogen atom, ionic hydrophilic group, substituted or unsubstituted alkylsulfonylamino group, substituted or unsubstituted arylsulfonylamino group, acylamino More preferably a hydrogen atom, an arylsulfonylamino group having an ionic hydrophilic group as a substituent, and an acylamino group having an ionic hydrophilic group as a substituent.
Y ₂ and Y ₄ each represent a hydrogen atom, and Y ₃ is most preferably an arylsulfonylamino group having an ionic hydrophilic group as a substituent and an acylamino group having an ionic hydrophilic group as a substituent.

(D) As the ionic hydrophilic group, —SO ₃ M ₁ or —CO ₂ M ₁ is preferable, —SO ₃ M ₁ is more preferable, and —SO ₃ Li is particularly preferable.

(E) Each of M ₁ and M independently represents a hydrogen atom or a monovalent counter cation. Examples of the monovalent counter cation include ammonium ions, alkali metal ions (eg, lithium ions, sodium ions, potassium ions). ) And organic cations (eg, tetramethylammonium ion, tetramethylguanidinium ion, tetramethylphosphonium), lithium salt, sodium salt, potassium salt, and ammonium salt are preferable, and lithium salt or lithium salt is the main component. The mixed salt is more preferable, and the lithium salt is most preferable.

The reason why this structure is preferable is that the water solubility of the azo compound of the general formula (1) is improved, and an azo dye structure capable of achieving both good hue and coloring power and high storage stability is electronically and sterically. It can be given.
As a result, storage stability as an aqueous solution is improved, and the required performance of the ink, which is light fastness, thermal stability, wet heat stability, water resistance, gas resistance and solvent resistance, is greatly improved. This is the most preferred example.

  The compound represented by the general formula (1) is preferably a compound represented by the following general formula (2).

  Hereinafter, the compound represented by the general formula (2) or a salt thereof will be described in detail.

(In General Formula (2), G represents a nitrogen atom or —C (R ₂ ) ═. R ₂ represents a hydrogen atom, a sulfo group, a carboxy group, a substituted or unsubstituted carbamoyl group, or a cyano group. R ₃ represents a monovalent substituent, A represents an aryl group or a nitrogen-containing 5-membered heterocyclic group, M represents a hydrogen atom or a monovalent counter cation, and n represents 0. Represents an integer of 1 or 2.)

Examples of G, R ₂ and M in the general formula (2) are each independently synonymous with examples of G, R ₂ and M in the general formula (1), and preferred examples are also the same.

Examples of the monovalent substituent represented by R ₃ in the general formula (2) include a substituent group A ′, which includes a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and a heterocyclic group. It is preferably an alkyl group or an aryl group substituted with an ionic hydrophilic group.

  The compound represented by the general formula (2) is preferably a compound represented by the following general formula (3).

  Hereinafter, the compound represented by the general formula (3) or a salt thereof will be described in detail.

(In General Formula (3), R ₃ represents a monovalent substituent. X ₁ , X ₂ , X ₃ , X ₄ , and X ₅ each independently represents a hydrogen atom or a monovalent substituent. M represents a hydrogen atom or a monovalent counter cation, and n represents an integer of 0, 1 or 2.)

  The example of M in General formula (3) is synonymous with the example of M in the said General formula (1), respectively, A preferable example is also the same.

Examples of the monovalent substituent represented by R ₃ in the general formula (3) include a substituent group A ′, which includes a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and a heterocyclic group. It is preferably an alkyl group or an aryl group substituted with an ionic hydrophilic group.

In the general formula (3), X ₁ , X ₂ , X ₃ , X ₄ , and X ₅ each independently represent a hydrogen atom or a monovalent substituent. Examples of the substituent when X ₁ , X ₂ , X ₃ , X ₄ , and X ₅ represent a substituent include the above-described substituent J.
X ₁ , X ₂ , X ₃ , X ₄ and X ₅ are each independently a hydrogen atom, an ionic hydrophilic group, a cyano group, a substituted or unsubstituted alkylsulfonyl group, a substituted or unsubstituted arylsulfonyl group, nitro Group, substituted or unsubstituted alkoxycarbonyl group, substituted or unsubstituted carbamoyl group, substituted or unsubstituted sulfamoyl group, hydrogen atom, ionic hydrophilic group, cyano group, methanesulfonyl group, phenylsulfonyl A group, a nitro group, a methoxycarbonyl group, and a carbamoyl group are more preferable, and a hydrogen atom, an ionic hydrophilic group, or a cyano group is particularly preferable.

In the general formula (3), X ₂ and X ₄ are preferably each independently a hydrogen atom or an ionic hydrophilic group. X ₁ , X ₃ , and X ₅ are preferably each independently a hydrogen atom or substituent group J, and at least one of X ₁ , X _3, and X ₅ has a Hammett σp value It preferably represents an electron withdrawing group of 0.3 or more. The upper limit of Hammett's substituent constant σp value is an electron withdrawing group of 1.0 or less.
If at least one of X ₁ , X ₃ , and X ₅ is an electron-withdrawing group having a σp value in this range, the hue of the azo compound can be adjusted, light fastness and ozone gas fastness can be improved. An effect can be acquired by using as a water-soluble dye for black ink.

  Specific examples of the electron withdrawing group having a σp value of 0.3 or more include acyl group, acyloxy group, carbamoyl group, alkyloxycarbonyl group, aryloxycarbonyl group, cyano group, nitro group, dialkylphosphono group, diaryl Phosphono group, diarylphosphinyl group, alkylsulfinyl group, arylsulfinyl group, alkylsulfonyl group, arylsulfonyl group, sulfonyloxy group, acylthio group, sulfamoyl group, thiocyanate group, thiocarbonyl group, halogenated alkyl group, halogenated Alkoxy group, halogenated aryloxy group, halogenated alkylamino group, halogenated alkylthio group, aryl group substituted with other electron-withdrawing group having σp value of 0.3 or more, nitro group, heterocyclic group, halogen Atom, azo group, or selenocyanate Group. A cyano group, a methylsulfonyl group, a phenylsulfonyl group, a methoxycarbonyl group, a carbamoyl group, and a nitro group are preferable, and a cyano group, a methylsulfonyl group, and a nitro group are more preferable.

From the viewpoint of hue, coloring power, and water-soluble storage stability, among the above, at least one of X ₂ , X ₃ , and X ₄ is preferably an ionic hydrophilic group, and X ₁ and X ₅ are It is preferably a hydrogen atom or an electron-withdrawing group having a Hammett's σp value of 0.3 or more, X ₁ , X ₃ and X ₅ are hydrogen atoms, and X ₂ and X ₄ are ionic hydrophilic groups It is more preferable that As the ionic hydrophilic group, —SO ₃ M ₁ or —CO ₂ M ₁ (M ₁ = Li, K, Ca, Mg, Ba) is preferable, —CO ₂ M ₁ is more preferable, and —CO ₂ Li is preferable. Particularly preferred.

  A particularly preferable combination as the compound represented by the general formula (3) includes the following (A) to (E).

(A) A is preferably an aryl group having a substituent, more preferably an ionic hydrophilic group or an aryl group having an electron-withdrawing group having a Hammett's σp value of 0.3 or more. More preferably, it is a phenyl group having two hydrophilic hydrophilic groups.

(B) G represents a nitrogen atom or —C (R ₂ ) ═, and preferably —C (R ₂ ) ═. R ₂ represents a hydrogen atom, a sulfo group, a carboxy group, a substituted or unsubstituted carbamoyl group, or a cyano group, preferably a carbamoyl group (—CONH ₂ group) or a cyano group, and preferably a cyano group. More preferred.

(C) As the monovalent substituent represented by R ₃ , substituent group A ′ can be mentioned, and it is preferably a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a heterocyclic group. More preferably an alkyl group or an aryl group substituted with an ionic hydrophilic group.

(2) As the ionic hydrophilic group, —SO ₃ M ₁ or —CO ₂ M ₁ is preferable, —SO ₃ M ₁ is more preferable, and —SO ₃ Li is particularly preferable.

(E) Each of M ₁ and M independently represents a hydrogen atom or a monovalent counter cation. Examples of the monovalent counter cation include ammonium ions, alkali metal ions (eg, lithium ions, sodium ions, potassium ions). ) And organic cations (eg, tetramethylammonium ion, tetramethylguanidinium ion, tetramethylphosphonium), lithium salt, sodium salt, potassium salt, and ammonium salt are preferable, and lithium salt or lithium salt is the main component. The mixed salt is more preferable, and the lithium salt is most preferable.

Factors in which this structure is preferable include that the water solubility of the azo compound of the general formula (3) and the association of the azo dye in the aqueous solution are remarkably improved, and in particular, the high storage stability in the aqueous solution is improved.
As a result, long-term storage stability is possible, and the required performance of the ink, which is light fastness, heat stability, wet heat stability, water resistance, gas resistance and / or solvent resistance, is greatly improved. An example.

  The compound represented by the general formula (1) or (2) is preferably a compound represented by the following general formula (4).

  Hereinafter, the compound represented by the general formula (4) or a salt thereof will be described in detail.

(In General Formula (4), R ₃ represents a monovalent substituent. X ₁ , X ₂ , X ₃ , X ₄ , and X ₅ are each independently a hydrogen atom or a monovalent substituent. M represents a hydrogen atom or a monovalent counter cation, and n represents an integer of 0, 1 or 2.)

Examples of R ₃ and M in the general formula (4) are each independently synonymous with examples of R ₃ and M in the general formula (3), and preferred examples are also the same.
_X 1 in the general formula _(4), X _2, X 3, _{X 4,} and examples of _{X 5,} respectively, _{X 1,} X _2, X 3, _{X 4} in the general formula (3), and X It is synonymous with the example of ₅ , and a preferable example is also the same.

  The present invention also relates to the azo compound represented by the general formula (1). An aqueous solution and a water-soluble ink composition using the azo compound of the present invention as a coloring agent (colorant) are used as coloring materials such as dyes and pigments. And a dispersant (such as a solvent) thereof, and can be suitably used for image formation.

(In General Formula (1), A represents an aryl group or a nitrogen-containing 5-membered heterocyclic group. G represents a nitrogen atom or —C (R ₂ ) ═. R ₂ represents a hydrogen atom or a sulfo group. group, a carboxy group, _.Y 2, _{Y 3} and _{Y 4} representing a substituted or unsubstituted carbamoyl group, or a cyano group independently, _.Y 2, _{Y 3} represents a hydrogen atom, or a monovalent substituent And Y ₄ may combine with each other to form a ring, M represents a hydrogen atom or a monovalent counter cation, and n represents an integer of 0, 1 or 2.)

  The azo compound represented by the general formula (1) is preferably an azo compound represented by the following general formula (3).

(In General Formula (3), R ₃ represents a monovalent substituent. X ₁ , X ₂ , X ₃ , X ₄ , and X ₅ each independently represents a hydrogen atom or a monovalent substituent. M represents a hydrogen atom or a monovalent counter cation, and n represents 0, 1 or 2.

  The azo compound represented by the general formula (1) is also preferably an azo compound represented by the following general formula (4).

(In General Formula (4), R ₃ represents a monovalent substituent. X ₁ , X ₂ , X ₃ , X ₄ , and X ₅ are each independently a hydrogen atom or a monovalent substituent. M represents a hydrogen atom or a monovalent counter cation, and n represents 0, 1 or 2.)

In the compounds represented by the general formulas (1) to (4), the maximum absorption wavelength (λ _max ) of an absorption spectrum measured using water as a solvent is preferably 550 nm to 700 nm, and more preferably 580 nm to 650 nm. Is particularly preferred.
In the present invention, the compounds represented by the general formulas (1) to (4) preferably have at least three ionic hydrophilic groups. More preferably, it has 3-6 ionic hydrophilic groups, and still more preferably 4-5 ionic hydrophilic groups. As a result, the water solubility and aqueous solution storage stability of the azo compound of the present invention are improved, the required performance as a water-soluble dye for inkjet recording black ink is satisfied at a high level, and the inkjet printed matter when used as an inkjet recording ink is further improved. There is an effect that the image quality can be further improved.
Moreover, in this invention, even if it contains isotopes (for example, 2H, 3H, 13C, 15N) in the compound represented by General formula (1)-(4), it is applicable.

  Specific examples of the compounds represented by the general formulas (1) to (4) are shown below, but the compounds used in the present invention are not limited to the following examples.

  The azo compound represented by the general formula (1) can be synthesized by a coupling reaction between a diazo component and a coupler, and these are described in JP-A No. 2003-306623 and Japanese Patent Application No. 2003-353498. There is.

[(C) pH adjuster]
The aqueous solution of the present invention can further contain (c) a pH adjuster.
As the pH adjuster, a neutralizer (organic base, inorganic alkali) can be used. For the purpose of improving the storage stability of the inkjet ink, the pH adjuster is preferably added so that the inkjet ink has a pH of 7.0 to 9.0, so that the pH is 7.5 to 8.5. It is more preferable to add.
The content of the pH adjuster in the aqueous solution of the present invention is preferably 0.05% by mass to 20% by mass and more preferably 0.1% by mass to 10% by mass with respect to the ink stock solution. It can be set as desired pH by making content of a pH adjuster into said range.

Examples of the pH adjuster include basic organic bases and inorganic bases, and acidic bases such as organic acids and inorganic acids.
Basic compounds include sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, lithium carbonate, sodium bicarbonate (sodium bicarbonate), potassium bicarbonate, lithium bicarbonate, sodium acetate, potassium acetate, Inorganic compounds such as sodium phosphate and sodium hydrogen phosphate, aqueous ammonia, methylamine, ethylamine, diethylamine, triethylamine, ethanolamine, diethanolamine, triethanolamine, ethylenediamine, piperidine, diazabicyclooctane, diazabicycloundecene, It is also possible to use organic bases such as pyridine, quinoline, picoline, lutidine and collidine, and alkali metal salts of organic acids such as lithium benzoate and potassium phthalate.
Examples of acidic compounds include inorganic compounds such as hydrochloric acid, sulfuric acid, phosphoric acid, boric acid, sodium hydrogen sulfate, potassium hydrogen sulfate, potassium dihydrogen phosphate, sodium dihydrogen phosphate, acetic acid, tartaric acid, benzoic acid, trifluoroacetic acid. Organic compounds such as methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, saccharic acid, phthalic acid, picolinic acid and quinolinic acid can also be used.
As a pH adjuster, sodium hydrogencarbonate, potassium hydrogencarbonate, and lithium hydrogencarbonate are preferable, sodium hydrogencarbonate and lithium hydrogencarbonate are more preferable, and lithium hydrogencarbonate is still more preferable.

Moreover, in this invention, you may adjust to a more preferable hue by using another colorant together with the said dye. Any dye can be used as the dye to be used in combination. For example, in yellow dyes, aryl or heteryl azo dyes having substituted benzenes, substituted naphthalenes, heterocycles such as pyrazolone and pyridone, open-chain active methylene compounds, etc. as coupling components (hereinafter referred to as coupler components); Examples include azomethine dyes having open-chain active methylene compounds as coupler components; methine dyes such as benzylidene dyes and monomethine oxonol dyes; and quinone dyes such as naphthoquinone dyes and anthraquinone dyes. Examples of other dye species include quinophthalone dyes, nitro / nitroso dyes, acridine dyes, and acridinone dyes. Particularly preferred in combination is a dye (S) having a λmax of 350 nm to 500 nm, and the above-mentioned and later-described yellow dyes can be used. Among them, an azo having 2 to 6 azo groups in one molecule is preferable. It is a dye. In the present invention, a yellow pigment can also be used.
In magenta dyes, aryl or heteryl azo dyes having phenols, naphthols, anilines, heterocycles such as pyridine and pyrazine, open-chain active methylene compounds, etc. as coupler components; for example, open-chain active methylene compounds as coupler components Azomethine dyes having the above; and anthrapyridone dyes. Particularly preferred are azo dyes having a hetero ring in the chromophore or an anthrapyridone dye.
For cyan dyes, aryl or hetaryl azo dyes having phenols, naphthols, anilines, etc. as coupler components; for example, azomethine dyes having phenols, naphthols, heterocyclic rings such as pyrrolotriazole, etc. as coupler components; cyanine dyes; Polymethine dyes such as oxonol dyes and merocyanine dyes; Carbonium dyes such as diphenylmethane dyes, triphenylmethane dyes and xanthene dyes; phthalocyanine dyes; anthraquinone dyes; Particularly preferred are phthalocyanine dyes.

  In particular, from the standpoint of fastness, a dye having an oxidation potential nobler than 1.0 V or an associative dye is preferable. Specific examples of preferable dyes used in combination include the dyes described in Japanese Patent Application No. 2003-360370.

As the heterocyclic azo dye, known yellow dyes and magenta dyes can be used in addition to the above black dyes. These yellow dyes and magenta dyes, which are heterocyclic azo dyes, preferably have at least one of the above properties (oxidation potential and association property), and more preferably have all the properties. The oxidation potential of these dyes is more preferably noble than 1.1 V (vs SCE), particularly preferably noble than 1.15 V (vs SCE).
As yellow dyes which are heterocyclic azo dyes, JP-A No. 2004-83903 (paragraph numbers [0048] to [0062]), 2003-277661 (paragraph numbers [0041] to [0050]), 2003-277661 are disclosed. Nos. (Paragraph numbers [0042] to [0047]) and US application publication US2003 / 0213405 (paragraph number [0108]).

  The aqueous solution of the present invention is prepared by dissolving in an aqueous medium when the dye is water-soluble, and dissolved and / or dispersed in an oleophilic medium and / or aqueous medium when the dye is oil-soluble. It is preferable to prepare them. The aqueous medium is a solvent mainly containing water, and optionally contains an organic solvent such as a water-miscible organic solvent. This organic solvent may have a function as a viscosity reducing agent. The lipophilic medium is mainly composed of an organic solvent.

  The use of the aqueous solution of the present invention is not particularly limited, but it is preferably used for inkjet.

[Ink composition]
The ink composition of the present invention contains the above aqueous solution.

The content of the compound represented by the general formula (1) in the ink composition is preferably 0.2 to 20% by mass, more preferably 0.5 to 10% by mass, and 1.0 to 8.0% by mass. % Is particularly preferred.
The ink composition of the present invention preferably contains 0.2 to 20% by mass of all dyes, more preferably 0.5 to 10% by mass, and particularly preferably 1.0 to 8.0% by mass. contains.

In the ink composition of the present invention, the pH of the ink composition at 25 ° C. is preferably adjusted to 7.0 to 10.0 with a pH adjuster, and the pH is adjusted to 7.5 to 9.5. More preferably. When pH is 7.5 or more, the solubility of dye improves and it can prevent clogging of a nozzle. Moreover, if pH is 9.5 or less, there exists a tendency for the long-term storage stability of an ink to be excellent.
Examples of the pH adjuster used in the ink composition include those used in the aqueous solution of the present invention, preferably lithium hydrogen carbonate, sodium hydrogen carbonate, and potassium hydrogen carbonate, more preferably lithium hydrogen carbonate, sodium hydrogen carbonate. .
The use of the ink composition of the present invention is not particularly limited, and is an ink composition for printing such as inkjet, an ink sheet in a heat-sensitive recording material, a color toner for electrophotography, an LCD, a display such as PDP, and the like. Although it can be preferably used for the preparation of a color filter used in an image pickup device such as a CCD and a dyeing solution for dyeing various fibers, an ink composition for inkjet recording is particularly preferable.
The above aqueous solution can be used in the method for producing the ink composition.
The ink composition is preferably black ink, but should not be limited to black ink, and can include ink of any color by mixing with other dyes or pigments.
The method for producing an ink composition includes a step (hereinafter also referred to as a liquid preparation step) of producing a desired ink composition having the above viscosity range using at least an aqueous solution.
The liquid preparation step is a step of preparing the aqueous solution obtained as described above into an ink composition having a specific viscosity and desired use, and may be a final product or an intermediate product. It may be. This preparation step includes at least a step of diluting the aqueous solution with a medium, preferably an aqueous medium. The aqueous solution containing the oil-soluble dye is not particularly limited in the medium used in this dilution step, but is preferably prepared as an aqueous ink composition by being emulsified and dispersed in an aqueous medium. The medium may contain various components of a necessary concentration, the components may be added to the aqueous solution separately, or both of them may be combined.
Since the ink composition manufactured according to the present invention is manufactured using an aqueous solution having a high dye concentration, the solubility of the dye is improved as compared with the ink composition manufactured by a normal method, and as a result, the ejection stability is improved. improves.

When producing an aqueous solution, it is preferable to add the process (filtering process) which removes the dust which is solid content by filtration. A filtration filter is used for this operation, and a filter having an effective diameter of 1 μm or less, preferably 0.3 μm or less is used as the filtration filter at this time. Various materials can be used as the filter material, but in the case of an aqueous solution of a water-soluble dye, it is preferable to use a filter prepared for an aqueous solvent. Among them, it is particularly preferable to use a jacket type filter made of a polymer material that is difficult to generate dust. As a filtration method, the jacket may be passed by liquid feeding, and either pressure filtration or vacuum filtration can be used.
In this invention, the viscosity reducing agent may be used and the said filtration process can be performed without resistance.

  Various methods such as dissolution by stirring, dissolution by ultrasonic irradiation, and dissolution by shaking can be used as a method for dissolving the dye and other components in the step of preparing the aqueous solution and the preparation step. Of these, the stirring method is particularly preferably used. In the case of stirring, various methods such as fluidized stirring known in the art and stirring using shearing force using an inverted agitator or dissolver can be used. On the other hand, a stirring method using a shearing force with the bottom surface of the container, such as a magnetic stirrer, can also be preferably used.

Next, the dye used for the aqueous solution and ink composition of the present invention will be described. The dye is not particularly limited. However, the half-value width (Wλ, _1/2 ) in the absorption spectrum of a diluted solution having a λmax of 500 nm to 700 nm and an absorbance normalized to 1.0 is 100 nm or more, preferably 120 nm. It is preferable to include at least one azo compound represented by the general formula (1) which is not less than 500 nm and more preferably not less than 120 nm and not more than 350 nm.

The azo compound represented by the general formula (1) alone has a high image quality “(good) black” = black that does not depend on the observation light source and any of the color tones of B, G, and R is difficult to be emphasized. Can be used alone as a raw material for an aqueous solution or an ink composition, however, the ink composition is usually used in combination with a dye that covers a region where the absorption of the dye is low. Is common. Usually, in the case of an ink composition using an azo compound represented by the general formula (1), it is preferably used in combination with another dye having a main absorption (λmax of 350 nm to 500 nm) in the yellow region. Further, it is also possible to prepare an ink composition in combination with other dyes.
Other dyes can be used in the aqueous solution, but are preferably mixed and used in the preparation of the ink composition from the viewpoint of storage stability.

  In the present invention, a black ink composition satisfying the following conditions is preferable in order to satisfy 1) excellent weather resistance and / or 2) that black balance is not lost even after fading.

First, the black square symbol of JIS code 2223 is printed at 48 points using the black ink composition, and the reflection density (D _vis ) measured by the status A filter (visual filter) is defined as the initial density. An example of a reflection density measuring machine equipped with a status A filter is an X-Rite density measuring machine. Here, when measuring the density of “black”, the measured value by D _vis is used as the standard observation reflection density. From this time (t) until the reflection density (D _vis ) reaches 80% of the initial reflection density value, this print is forcibly faded using an ozone fading tester capable of always generating 5 ppm of ozone. The forced fading rate constant (k _vis ) is obtained from the relational expression “0.8 = exp (−k _vis · t)”.
In the present invention, the rate constant (k _vis ) is 5.0 × 10 ⁻² [hour ⁻¹ ] or less, preferably 3.0 × 10 ⁻² [hour ⁻¹ ] or less, more preferably 1.0 × 10 ^{−. 2} [hour ^-1 ] An ink composition having the following ^value is prepared.

Also, a black square symbol of JIS code 2223 is printed at 48 points using a black ink composition, and this is a density measurement value measured by a status A filter, which is not D _vis C (cyan), M (magenta), The reflection density (D _R , D _G , D _B ) of the three colors Y (yellow) is also defined as the initial density. Here, (D _R , D _G , D _B ) indicates (C reflection density by the red filter, M reflection density by the green filter, and Y reflection density by the blue filter). This print is forcibly faded using an ozone fading tester capable of always generating 5 ppm of ozone according to the above method, and the respective reflection densities (D _R , D _G , D _B ) are 80% of the initial density value. Similarly, the forced fading rate constants (k _R , k _G , k _B ) are determined from the time until. When the three rate constants are obtained and the ratio (R) between the maximum value and the minimum value is obtained (for example, when k _R is the maximum value and k _G is the minimum value, R = k _R / k _G ) The ink composition is prepared so that the ratio (R) is 1.2 or less, preferably 1.1 or less, more preferably 1.05 or less.

  Note that the “printed matter in which the black square symbol of the JIS code 2223 is printed at 48 points” used above gives an image large enough to cover the aperture of the measuring instrument in order to give a sufficient size for density measurement. It is printed.

Examples of the dye used in the aqueous solution of the present invention, and thus the ink composition, include a dye having an azo group bonded to a heterocyclic ring (hereinafter also referred to as “heterocyclic azo dye”) and an associative phthalocyanine dye (hereinafter referred to as a heterocyclic ring). The azo dyes and the dyes used in the present invention such as the phthalocyanine dyes are generally referred to as dyes for the present invention). The present invention preferably contains at least one heterocyclic azo dye or the phthalocyanine dye, but other dyes and / or pigments may be used in combination.
In addition, the dye used in the present invention preferably has an oxidation potential of 1.0 V (vs SCE) or more.
A person skilled in the art can easily measure the value of the oxidation potential (Eox). Regarding this method, see, for example, P.I. Delahay, “New Instrumental Methods in Electrochemistry” (published by Interscience Publishers, 1954) J. et al. "Electrochemical Methods" by Bard et al. (Published by John Wiley & Sons in 1980) and "Electrochemical Measurement Method" by Akira Fujishima et al. (Published by Gihodo Publishing Co., Ltd. in 1984).

Specifically, the oxidation potential is 1 × 10 ⁻² to 1 × 10 ⁻⁶ mol / min in a solvent such as dimethylformamide or acetonitrile containing a supporting electrolyte such as sodium perchlorate or tetrapropylammonium perchlorate. It is measured as a value relative to SCE (saturated calomel electrode) using various voltammetry (polarography using a dropping mercury electrode, cyclic voltammetry, a method using a rotating disk electrode, etc.). Although this value may be deviated by several tens of mil volts due to the influence of the liquid potential difference or the liquid resistance of the sample solution, the reproducibility of the potential can be ensured by inserting a standard sample (for example, hydroquinone).
In the present invention, SCE (saturated calomel) is used as a reference electrode in N, N-dimethylformamide (concentration of dye is 0.001 mol / liter) containing 0.1 mol / liter of tetrapropylammonium perchlorate as a supporting electrolyte. Electrode), a value (vs SCE) measured using a graphite electrode as a working electrode and a platinum electrode as a counter electrode was defined as an oxidation potential of the dye.

  The value of Eox represents the ease of electron transfer from the sample to the electrode, and the greater the value (the higher the oxidation potential), the more difficult the electron transfer from the sample to the electrode, in other words, the less easily oxidized. In relation to the structure of the compound, the oxidation potential becomes more noble by introducing an electron withdrawing group, and the oxidation potential becomes lower by introducing an electron donating group. In the present invention, in order to lower the reactivity with ozone as an electrophile, it is desirable to introduce an electron withdrawing group into the dye skeleton to make the oxidation potential more noble.

Moreover, as a dye used in the present invention, ε1 / ε2 is preferably 1.1 or more, more preferably 1.1 to 1.5, and particularly preferably 1.2 to 1.5 in the following associative evaluation method. .
Assessing method of dye associative property The associating property of a dye can be evaluated as follows. When a 0.01 mmol / L dye solution was measured using a cell with an optical path length of 1 cm, a molecular absorption coefficient (ε1) of the solution absorption spectrum and a 20 mmol / L dye solution with an optical path length of 5 μm were used. The ratio of the solution absorption spectrum to the molecular extinction coefficient (ε2), ε1 / ε2, is an indicator of dye association. The higher this number, the easier the dye will associate. A dye having a value of 1.1 or more exhibits excellent performance in ozone resistance and light resistance due to dye association.
The above solvent used for the dye solution is ultrapure water with a specific resistance value of 18 MΩ · cm or more such as deionized water if the dye is water-soluble, and a uniform solution if the dye is oil-soluble Is measured using an organic solvent in which the dye is soluble, or a dispersion or emulsion in ultrapure water similar to the case of the water-soluble dye.

  Examples of dyes that can be used in the present invention include the following. A single dye is used in combination in order to adjust the color tone. The ink composition obtained from each of the yellow, magenta, cyan, and black ink stock solutions of the present invention can be used not only for forming a single color image but also for forming a full color image. In order to form a full-color image, a two-color ink composition can be used for each color. Furthermore, ink compositions of intermediate colors such as red, green, blue, and violet can also be used. The ink composition of the present invention can constitute an ink set for obtaining a full-color image. Alternatively, the ink composition can form part of an ink set. In other words, any ink composition other than the present invention may be combined with the ink composition of the present invention to constitute an ink set.

In addition, in order to obtain a full-color image together with the dye, another colorant may be used in combination with the ink composition of the present invention in order to adjust the color tone.
Any colorant can be used as the colorant that can be used in the ink set of the present invention or the colorant that can be used in combination with the dye. Examples of the dye that can be used in combination include the dyes described so far and the following.
As yellow dyes, for example, phenols, naphthols, anilines, pyrazolones, pyridones, aryl or heteryl azo dyes having open-chain active methylene compounds as coupling components; for example, open-chain active methylene compounds as coupling components Azomethine dyes; methine dyes such as benzylidene dyes and monomethine oxonol dyes; quinone dyes such as naphthoquinone dyes and anthraquinone dyes; And dyes, acridine dyes, acridinone dyes and the like. These dyes may be those that exhibit yellow only after a part of the chromophore is dissociated, in which case the counter cation may be an alkali metal or an inorganic cation such as ammonium, pyridinium, It may be an organic cation such as a quaternary ammonium salt, and may further be a polymer cation having them in a partial structure.

  Examples of magenta dyes include, for example, aryl or heteryl azo dyes having phenols, naphthols, and anilines as coupling components; azomethine dyes having pyrazolones and pyrazolotriazoles as coupling components; for example, arylidene dyes, styryl dyes, and merocyanine Dyes, methine dyes such as oxonol dyes; carbonium dyes such as diphenylmethane dyes, triphenylmethane dyes, xanthene dyes, quinone dyes such as naphthoquinone, anthraquinone, anthrapyridone, etc. And ring dyes. These dyes may exhibit magenta only after part of the chromophore is dissociated, and the counter cation in that case may be an alkali metal or an inorganic cation such as ammonium, pyridinium, It may be an organic cation such as a quaternary ammonium salt, and may further be a polymer cation having them in a partial structure.

  Examples of the cyan dye include azomethine dyes such as indoaniline dyes and indophenol dyes; polymethine dyes such as cyanine dyes, oxonol dyes and merocyanine dyes; carbonium dyes such as diphenylmethane dyes, triphenylmethane dyes and xanthene dyes; phthalocyanine Dyes; anthraquinone dyes; for example, aryl or heteryl azo dyes having phenols, naphthols and anilines as coupling components, and indigo / thioindigo dyes. These dyes may exhibit cyan only after a part of the chromophore is dissociated, and the counter cation in that case may be an alkali metal or an inorganic cation such as ammonium, pyridinium, It may be an organic cation such as a quaternary ammonium salt, and may further be a polymer cation having them in a partial structure.

In addition, water-soluble dyes such as direct dyes, acid dyes, food dyes, basic dyes, and reactive dyes can be used in combination. Among them, preferred is
CI Direct Red 1, 2, 4, 9, 11, 23, 26, 31, 37, 39, 62, 63, 72, 75, 76, 79, 80, 81, 83, 84, 87, 89, 92, 95 111, 173, 184, 207, 211, 212, 214, 218, 21, 223, 224, 225, 226, 227, 232, 233, 240, 241, 242, 243, 247, 254, CI Direct Violet 7, 9, 47, 48, 51, 66, 90, 93, 94, 95, 98, 100, 101
CI Direct Yellow 4, 8, 9, 11, 12, 27, 28, 29, 33, 35, 39, 41, 44, 50, 53, 58, 59, 68, 86, 87, 93, 95, 96, 98 , 100, 106, 108, 109, 110, 120, 130, 132, 142, 144, 157, 161, 163
CI Direct Blue 1, 10, 15, 22, 25, 55, 67, 68, 71, 76, 77, 78, 80, 84, 86, 87, 90, 98, 106, 108, 109, 151, 156, 158 , 159, 160, 168, 189, 192, 193, 194, 199, 200, 201, 202, 203, 207, 211, 213, 214, 218, 225, 229, 236, 237, 244, 248, 249, 251 , 252, 264, 270, 280, 288, 289, 290, 291
CI Direct Black 9, 17, 19, 22, 32, 51, 56, 62, 69, 77, 80, 91, 94, 97, 108, 112, 113, 114, 117, 118, 121, 122, 125, 132 , 146, 154, 166, 168, 173, 199
CI Acid Red 1, 8, 35, 42, 52, 57, 62, 80, 81, 82, 87, 94, 111, 114, 115, 118, 119, 127, 128, 131, 143, 144, 151, 152 , 154, 158, 186, 245, 249, 254, 257, 261, 263, 266, 289, 299, 301, 305, 336, 337, 361, 396, 397
CI Acid Violet 5, 34, 43, 47, 48, 90, 103, 126
CI Acid Yellow 17, 19, 23, 25, 39, 40, 42, 44, 49, 50, 61, 64, 76, 79, 110, 127, 135, 143, 151, 159, 169, 174, 190, 195 , 196, 197, 199, 218, 219, 222, 227, CI Acid Blue 9, 25, 40, 41, 62, 72, 76, 78, 80, 82, 87, 92, 106, 112, 113, 120, 127: 1,129,138,143,175,181,185,205,207,220,221,230,232,247,249,258,260,264,271,277,278,279,280,288, 290, 326
CI Acid Black 7, 24, 29, 48, 52: 1, 172
CI Reactive Red 3, 6, 13, 17, 19, 21, 22, 23, 24, 29, 35, 37, 40, 41, 43, 45, 49, 55, 63, 106, 107, 112, 113, 114, 126, 127, 128, 129, 130, 131, 137, 160, 161, 174, 180
CI Reactive Violet 1, 3, 4, 5, 6, 7, 8, 9, 16, 17, 22, 23, 24, 26, 27, 33, 34
CI Reactive Yellow 2, 3, 13, 14, 15, 17, 18, 23, 24, 25, 26, 27, 29, 35, 37, 41, 42
CI Reactive Blue 2, 3, 5, 7, 8, 10, 13, 14, 15, 17, 18, 19, 21, 25, 26, 27, 28, 29, 38, 82, 89, 158, 182, 190, 203, 216, 220, 244
CI Reactive Black 4, 5, 8, 14, 21, 23, 26, 31, 32, 34
CI Basic Red 12, 13, 14, 15, 18, 22, 23, 24, 25, 27, 29, 35, 36, 38, 39, 45, 46
CI Basic Violet 1, 2, 3, 7, 10, 15, 16, 20, 21, 25, 27, 28, 35, 37, 39, 40, 48
CI Basic Yellow 1, 2, 4, 11, 13, 14, 15, 19, 21, 23, 24, 25, 28, 29, 32, 36, 39, 40
CI Basic Blue 1, 3, 5, 7, 9, 22, 26, 41, 45, 46, 47, 54, 57, 60, 62, 65, 66, 69, 71
CI Basic Black 8,
Etc.

In addition to the dye represented by the above formula, dyes described in the following publications can also be preferably used.
JP-A-10-130557, JP-A-9-255906, JP-A-6-234944, JP-A-7-97541, EP 982371, WO 00/43450, WO 00/43451, WO 00/43452, WO 00 / 43453, WO 03/106572, WO 03/104332, JP 2003-238862, JP 2004-83609, JP 2002-302619, JP 2002-327131, JP 2002-265809, WO 01 / 48090, WO 04/087815, WO 02/90441, WO 03/027185, WO 04/085541, JP 2003-321627, JP 2002-332418, JP 2002-332419, WO 02/059215, WO 02 / 059216, WO 0 No. 087814, WO 04/046252, WO 04/046265, U.S. Pat. No. 2004-285351, WO 04/078860, JP-A No. 2004-323605, WO 04/104108.

Furthermore, in the present invention, a pigment can be used in combination with a dye.
As the pigment that can be used in the present invention, commercially available pigments and known pigments described in various documents can be used. Regarding the literature, the Color Index (Edited by The Society of Dyers and Colorists), “Revised New Handbook of Pigments” edited by the Japan Pigment Technology Association (published in 1989), “Latest Pigment Applied Technology” published by CMC (published in 1986), “Printing Ink Technology” CMC Publishing (1984), W. Herbst, K.M. Hunger co-authored Industrial Organic Pigments (VCH Verlagsgesellschaft, published in 1993). Specifically, as organic pigments, azo pigments (azo lake pigments, insoluble azo pigments, condensed azo pigments, chelate azo pigments), polycyclic pigments (phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, indigo pigments, quinacridone Pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, diketopyrrolopyrrole pigments, etc.), dyed lake pigments (acid or basic dye lake pigments), azine pigments, etc. C.I. of yellow pigment I. Pigment Yellow 34, 37, 42, 53, and other red pigments such as C.I. I. Pigment Red 101, 108, etc., blue pigments such as C.I. I. Pigment Blue 27, 29, 17: 1, etc., black pigments such as C.I. I. Pigment Black 7, magnetite, and other white pigments such as C.I. I. Pigment White 4, 6, 18, 21 and the like.

  As a pigment having a preferable color tone for image formation, a phthalocyanine pigment, an anthraquinone-based indanthrone pigment (for example, CI Pigment Blue 60), and a dyed lake pigment-based triarylcarbonium pigment are preferable for a blue or cyan pigment. Phthalocyanine pigments (preferred examples include copper phthalocyanine such as CI Pigment Blue 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, monochloro or low chlorinated copper) Among the phthalocyanines and alnium phthalocyanines, the pigments described in European Patent No. 860475, the metal-free phthalocyanine which is CI Pigment Blue 16, the phthalocyanines whose central metals are Zn, Ni and Ti, among them, CI pigment is preferable. Blue 5: 3, 15: 4 and aluminum phthalocyanine) are most preferred.

  For red to purple pigments, azo pigments (preferred examples include CI Pigment Red 3, 5, 11, 22, 38, 48: 1, 48: 2, 48: 3, 48: 4, 49: 1, 52: 1, 53: 1, 57: 1, 63: 2, 144, 146, and 184). I. Pigment Red 57: 1, 146, 184), quinacridone pigments (preferred examples include CI Pigment Red 122, 192, 202, 207, 209, CI Pigment Violet 19, 42, particularly preferred are CI Pigment Red 122), dyed lake pigment-based triarylcarbonium pigments (preferred examples include xanthene-based CI Pigment Red 81: 1, CI Pigment Violet). 1, 2, 3, 27, 39), dioxazine pigments (for example, CI Pigment Violet 23, 37), diketopyrrolopyrrole pigments (for example, CI Pigment Red 254), perylene Pigments (e.g. CI Pigment) Iolet 29), anthraquinone pigments (e.g., C.I. Pigment Violet 5: 1, the 31, the 33), thioindigo (e.g. C.I. Pigment Red 38, the 88) is preferably used.

  As yellow pigments, azo pigments (preferred examples include monoazo pigment-based CI Pigment Yellow 1, 3, 74, 98, disazo pigment-based CI Pigment Yellow 12, 13, 14, 16, 17, 83, synthetic azo-based CI Pigment Yellow 93, 94, 95, 128, 155, benzimidazolone-based CI Pigment Yellow 120, 151, 154, 156, 180, etc., among which benzidine is preferable. That are not used as raw materials), isoindoline / isoindolinone pigments (preferred examples include CI Pigment Yellow 109, 110, 137, and 139), and quinophthalone pigments (preferably examples include CI. .Pigment Yellow 138) and Frapantron pigments (for example, CI Pigment Yellow 24) are preferably used.

Preferred examples of the black pigment include inorganic pigments (preferably carbon black and magnetite as examples) and aniline black.
In addition, an orange pigment (such as CI Pigment Orange 13, 16) or a green pigment (such as CI Pigment Green 7) may be used.

The pigment that can be used in the present invention may be the above-mentioned bare pigment or a surface-treated pigment. Surface treatment methods include resin or wax surface coating, surfactant deposition, reactive substances (eg radicals derived from silane coupling agents, epoxy compounds, polyisocyanates, diazonium salts, etc.) pigments A method of bonding to the surface is conceivable and is described in the following documents and patents.
(1) Properties and applications of metal soap (Sachishobo)
(2) Printing ink printing (CMC Publishing 1984)
(3) Latest pigment application technology (CMC Publishing 1986)
(4) U.S. Pat. Nos. 5,554,739, 5,571,311 (5) JP-A-9-151342, 10-140065, 10-292143, 11-166145 Self-dispersing pigments prepared by allowing a diazonium salt described in US Patent 4) to act on carbon black, or encapsulated pigments prepared by the method described in Japanese Patent (5) above are ink compositions. This is particularly effective because dispersion stability can be obtained without using an extra dispersant in the product.

In the present invention, the pigment may be further dispersed using a dispersant. Various known dispersants can be used in accordance with the pigment to be used, for example, a surfactant-type low-molecular dispersant or a polymer-type dispersant. Examples of the dispersant include those described in JP-A-3-69949, European Patent 549486 and the like. In addition, when a dispersant is used, a pigment derivative called a synergist may be added to promote adsorption of the dispersant to the pigment.
The particle size of the pigment that can be used in the present invention is preferably in the range of 0.01 to 10 μm after dispersion, and more preferably 0.05 to 1 μm.
As a method for dispersing the pigment, a known dispersion technique used in ink production or toner production can be used. Examples of the dispersing machine include vertical or horizontal agitator mills, attritors, colloid mills, ball mills, three roll mills, pearl mills, super mills, impellers, dispersers, KD mills, dynatrons, and pressure kneaders. Details are described in "Latest Pigment Application Technology" (CMC Publishing, 1986).

  Examples of water-soluble dyes used in the present invention include magenta dyes described in JP-A No. 2002-371214, phthalocyanine dyes described in JP-A No. 2002-309118, JP-A Nos. 2003-12952 and 2003-12956. It is also preferable to use the dyes described in water-soluble phthalocyanine dyes.

  The ink composition of the present invention contains a dye in a medium, preferably in an aqueous medium. The aqueous medium is added with water or a solvent such as a water-miscible organic solvent as necessary. The water-miscible organic solvent may be a viscosity reducing agent in the ink stock solution as described above.

  The water-miscible organic solvent that can be used in the present invention is a material having functions such as an anti-drying agent, a penetration accelerator, and a wetting agent for an ink composition for inkjet recording in the field, and is mainly a high-boiling water. A miscible organic solvent is used. Such compounds include alcohols (eg, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, t-butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol), polyhydric alcohols (eg, , Ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol), glycol derivatives (eg, ethylene glycol monomethyl) Ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether Diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, triethylene glycol monomethyl ether, ethylene glycol diacetate, ethylene glycol monomethyl ether acetate, triethylene glycol Monomethyl ether, triethylene glycol monoethyl ether, ethylene glycol monophenyl ether), amine (for example, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenetriamine) , Reethylenetetramine, polyethyleneimine, tetramethylpropylenediamine) and other polar solvents (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, sulfolane, 2-pyrrolidone, N-methyl-2- Pyrrolidone, N-vinyl-2-pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, acetonitrile, acetone). In addition, the said water miscible organic solvent may use 2 or more types together.

Among these, alcohol solvents are particularly preferable. The ink composition of the present invention preferably contains a water-miscible organic solvent having a boiling point of 150 ° C. or higher, and examples thereof include 2-pyrrolidone selected from the above.
These water-miscible organic solvents are preferably contained in the ink composition in a total amount of 5 to 60% by mass, particularly preferably 10 to 45% by mass.

By incorporating a surfactant into the ink composition of the present invention and adjusting the liquid physical properties of the ink composition, the ejection stability of the ink composition is improved, the water resistance of the image is improved, and the printed ink composition It is possible to have an excellent effect in preventing bleeding.
Examples of the surfactant include anionic surfactants such as sodium dodecyl sulfate, sodium dodecyloxysulfonate, and sodium alkylbenzene sulfonate, and cationic surfactants such as cetyl pyridinium chloride, trimethyl cetyl ammonium chloride, and tetrabutyl ammonium chloride. And nonionic surfactants such as polyoxyethylene nonylphenyl ether, polyoxyethylene naphthyl ether, polyoxyethylene octylphenyl ether, and the like. Among these, nonionic surfactants are particularly preferably used.

  The content of the surfactant is 0.001 to 20% by mass, preferably 0.005 to 10% by mass, and more preferably 0.01 to 5% by mass with respect to the ink composition.

When the dye is an oil-soluble dye, the ink composition of the present invention can be prepared by emulsifying and dispersing an ink stock solution in which the oil-soluble dye is dissolved in a high-boiling organic solvent in an aqueous medium.
The boiling point of the high-boiling organic solvent used in the present invention is 150 ° C. or higher, preferably 170 ° C. or higher.
For example, phthalic acid esters (for example, dibutyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, di-2-ethylhexyl phthalate, decyl phthalate, bis (2,4-di-tert-amylphenyl) isophthalate, bis (1, 1-diethylpropyl) phthalate), esters of phosphoric acid or phosphones (eg diphenyl phosphate, triphenyl phosphate, tricresyl phosphate, 2-ethylhexyl diphenyl phosphate, dioctyl butyl phosphate, tricyclohexyl phosphate, tri-2-ethylhexyl phosphate , Tridodecyl phosphate, di-2-ethylhexyl phenyl phosphate), benzoic acid esters (eg 2-ethylhexyl benzoate, 2,4-dicarbonate) Lobenzoate, dodecylbenzoate, 2-ethylhexyl-p-hydroxybenzoate), amides (eg, N, N-diethyldodecanamide, N, N-diethyllaurylamide), alcohols or phenols (isostearyl alcohol, 2, 4-di-tert-amylphenol), aliphatic esters (eg, dibutoxyethyl succinate, di-2-ethylhexyl succinate, 2-hexyldecyl tetradecanoate, tributyl citrate, diethyl azelate, isostearyl lactate , Trioctyl citrate), aniline derivatives (N, N-dibutyl-2-butoxy-5-tert-octylaniline, etc.), chlorinated paraffins (paraffins having a chlorine content of 10% to 80%), trimesic acid esters Class (for example, Tributyl rimesate), dodecylbenzene, diisopropylnaphthalene, phenols (eg, 2,4-di-tert-amylphenol, 4-dodecyloxyphenol, 4-dodecyloxycarbonylphenol, 4- (4-dodecyloxyphenylsulfonyl)) Phenol), carboxylic acids (eg, 2- (2,4-di-tert-amylphenoxybutyric acid, 2-ethoxyoctanedecanoic acid), alkylphosphoric acids (eg, di-2 (ethylhexyl) phosphoric acid, diphenylphosphoric acid) The high-boiling organic solvent can be used in an amount of 0.01 to 3 times, preferably 0.01 to 1.0 times the mass ratio of the oil-soluble dye.
These high-boiling organic solvents may be used alone or in a mixture of several types (eg tricresyl phosphate and dibutyl phthalate, trioctyl phosphate and di (2-ethylhexyl) sebacate, dibutyl phthalate and poly (Nt-butyl). Acrylamide)].

Examples of other high boiling point organic solvents used in the present invention and / or methods for synthesizing these high boiling point organic solvents are disclosed in, for example, US Pat. Nos. 2,322,027, 2,533,514, and 2 772,163, 2,835,579, 3,594,171, 3,676,137, 3,689,271, 3,700,454 3,748,141, 3,764,336, 3,765,897, 3,912,515, 3,936,303, 4, No. 004,928, No. 4,080,209, No. 4,127,413, No. 4,193,802, No. 4,207,393, No. 4,220,711, No. 4,239,851, No. 4,278,757, No. 4, 53,979, 4,363,873, 4,430,421, 4,430,422, 4,464,464, 4,483,918, 4,540,657, 4,684,606, 4,728,599, 4,745,049, 4,935,321, 5,013 , 639, European Patent Nos. 276,319A, 286,253A, 289,820A, 309,158A, 309,159A, 309,160A, 509 No. 311A, No. 510,576A, East German Patent No. 147,009, No. 157,147, No. 159,573, No. 225,240A, British Patent No. 2,091,124A, JP-A-48-47335, 50- No. 6530, No. 51-25133, No. 51-26036, No. 51-27921, No. 51-27922, No. 51-149028, No. 52-46816, No. 53-1520, No. 53-1521 53-15127, 53-146622, 54-91325, 54-106228, 54-118246, 55-59464, 56-64333, 56-81836, 59-204041, 61-84641, 62-118345, 62-247364, 63-167357, 63-214744, 63-301941, 63-94552, 64-945 9454, 64-68745, JP-A-1-101543, 1-1202454, 2-792, 2- No. 4239, No. 2-43541, No. 4-29237, No. 4-30165, No. 4-232946, No. 4-346338 and the like.
The high boiling point organic solvent is used in an amount of 0.01 to 3.0 times, preferably 0.01 to 1.0 times the mass ratio of the oil-soluble dye.

  In the present invention, the oil-soluble dye and the high boiling point organic solvent are preferably emulsified and dispersed in an aqueous medium. In the emulsification dispersion, a low boiling organic solvent can be used depending on the case from the viewpoint of emulsification. The low boiling point organic solvent is an organic solvent having a boiling point of about 30 ° C. or higher and 150 ° C. or lower at normal pressure. For example, esters (eg ethyl acetate, butyl acetate, ethyl propionate, β-ethoxyethyl acetate, methyl cellosolve acetate), alcohols (eg isopropyl alcohol, n-butyl alcohol, secondary butyl alcohol), ketones (eg methyl isobutyl) Ketones, methyl ethyl ketone, cyclohexanone), amides (for example, dimethylformamide, N-methylpyrrolidone), ethers (for example, tetrahydrofuran, dioxane) and the like are preferably used, but are not limited thereto.

The emulsification dispersion is used to disperse an oil phase in which a dye is dissolved in a mixed solvent of a high-boiling organic solvent and, optionally, a low-boiling organic solvent, in an aqueous phase mainly composed of water to form fine oil droplets in the oil phase. (The oil layer may be used as an ink stock solution, or the oil layer dispersed in the water phase may be used as an ink stock solution). At this time, components such as a surfactant, a wetting agent, a dye stabilizer, an emulsion stabilizer, an antiseptic, and an antifungal agent can be added to either or both of the aqueous phase and the oil phase as necessary. .
As an emulsification method, a method of adding an oil phase to an aqueous phase is common, but a so-called phase inversion emulsification method in which an aqueous phase is dropped into an oil phase can also be preferably used. The emulsification method can also be applied when the dye is water-soluble and the component is oil-soluble.

  When emulsifying and dispersing, various surfactants can be used. Anionic interfaces such as fatty acid salts, alkyl sulfate esters, alkyl benzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinates, alkyl phosphate esters, naphthalene sulfonate formalin condensates, polyoxyethylene alkyl sulfates, etc. Activator, polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester, oxyethyleneoxypropylene block copolymer Nonionic surfactants such as Further, SURFYNOLS (Air Products & Chemicals), which is an acetylene-based polyoxyethylene oxide surfactant, is also preferably used. An amine oxide type amphoteric surfactant such as N, N-dimethyl-N-alkylamine oxide is also preferred. Further, pages (37) to (38) of JP-A-59-157,636, Research Disclosure No. The surfactants described in 308119 (1989) can also be used.

For the purpose of stabilization immediately after emulsification, a water-soluble polymer can be added in combination with the surfactant. As the water-soluble polymer, polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene oxide, polyacrylic acid, polyacrylamide or a copolymer thereof is preferably used. It is also preferable to use natural water-soluble polymers such as polysaccharides, casein, and gelatin. Further, for stabilization of the dye dispersion, acrylic acid esters, methacrylic acid esters, vinyl esters, acrylamides, methacrylamides, olefins, styrenes, vinyl ethers that are substantially insoluble in an aqueous medium, Polyvinyl, polyurethane, polyester, polyamide, polyurea, polycarbonate and the like obtained by polymerization of acrylonitrile can also be used in combination. These polymers preferably contain —SO ₃ ⁻ and —COO ⁻ . When these polymers that are substantially insoluble in an aqueous medium are used in combination, it is preferably used in an amount of 20% by mass or less, more preferably 10% by mass or less of the high-boiling organic solvent.

When an oil-soluble dye or a high-boiling organic solvent is dispersed by emulsification to obtain an aqueous ink composition, control of the particle size is particularly important. In order to increase color purity and density when an image is formed by inkjet, it is essential to reduce the average particle size. The volume average particle size is preferably 1 μm or less, more preferably 5 to 100 nm.
In addition to static light scattering, dynamic light scattering, and centrifugal sedimentation, the methods for measuring the volume average particle size and particle size distribution of the dispersed particles are described on pages 417 to 418 of Experimental Chemistry Course 4th edition. It can be easily measured by a known method such as using a method. For example, it is diluted with distilled water so that the particle concentration in the ink composition is 0.1 to 1% by mass, and a commercially available volume average particle size measuring device (for example, Microtrac UPA (manufactured by Nikkiso Co., Ltd.)) Can be measured easily. Furthermore, the dynamic light scattering method using the laser Doppler effect is particularly preferable because it can measure the particle size up to a small size.
The volume average particle diameter is an average particle diameter weighted by the particle volume, and is the sum of the diameter of each particle multiplied by the volume of the particle divided by the total volume of the particles. The volume average particle diameter is described on page 119 of “Chemistry of Polymer Latex (by Soichi Muroi, Polymer Press Society)”.

It was also found that the presence of coarse particles also plays a very important role in printing performance. That is, it has been found that the coarse particles clog the nozzles of the head, or even if the clogs are not clogged, non-ejection of the ink composition or misalignment of the ink composition occurs, which has a significant effect on printing performance. In order to prevent this, it is important to reduce the number of particles of 5 μm or more to 10 or less and 1 μm or more to 1000 or less in 1 μl of the ink composition when the ink composition is formed.
As a method for removing these coarse particles, a known centrifugal separation method, microfiltration method, or the like can be used. These separation means may be performed immediately after the emulsification dispersion, or may be performed immediately after filling the ink dispersion after adding various components such as a wetting agent and a surfactant to the emulsification dispersion.
A mechanical emulsifier can be used as an effective means for reducing the average particle size and eliminating coarse particles.

As the emulsifying device, known devices such as a simple stirrer, impeller stirring method, in-line stirring method, mill method such as colloid mill, and ultrasonic method can be used, but the use of a high-pressure homogenizer is particularly preferable.
The high-pressure homogenizer is described in detail in US Pat. No. 4,533,254, JP-A-6-47264, and the like, but as a commercially available device, a Gorin homogenizer (APV GAULIN INC.), A microfluidizer ( MICROFLUIDEX INC.), Optimizer (Sugino Machine Co., Ltd.) and the like.
In addition, a high-pressure homogenizer equipped with a mechanism for atomizing in an ultrahigh-pressure jet stream as described in US Pat. No. 5,720,551 in recent years is particularly effective for the emulsification dispersion of the present invention. An example of an emulsifying apparatus using this ultra-high pressure jet flow is DeBEE2000 (BEE INTERNIONAL LTD.).

The pressure when emulsifying with the high-pressure emulsifying dispersion device is 50 MPa or more, preferably 60 MPa or more, more preferably 180 MPa or more.
For example, it is a particularly preferable method that two or more types of emulsifiers are used in combination by a method such as emulsification with a stirring emulsifier and then passing through a high-pressure homogenizer. Also preferred is a method of once emulsifying and dispersing with these emulsifying apparatuses, adding components such as a wetting agent and a surfactant, and then passing again through the high-pressure homogenizer while the cartridge is filled with the ink composition.
When a low boiling point organic solvent is contained in addition to the high boiling point organic solvent, it is preferable to remove the low boiling point solvent from the viewpoint of the stability of the emulsion and safety and health. Various known methods can be used as the method for removing the low boiling point solvent depending on the type of the solvent. That is, an evaporation method, a vacuum evaporation method, an ultrafiltration method, and the like. This step of removing the low-boiling organic solvent is preferably performed as soon as possible immediately after emulsification.

  The method for preparing the inkjet ink composition is described in detail in JP-A Nos. 5-148436, 5-295212, 7-97541, 7-82515, and 7-118584. And can be used to prepare the ink composition of the present invention.

  The ink composition of the present invention can contain a functional component for imparting various functions to the ink composition. For example, as the functional component, the above-mentioned various solvents, an anti-drying agent for preventing clogging due to dry operation at the ink composition ejection port, a penetration enhancer for allowing the ink composition to penetrate well into paper, Examples include ultraviolet absorbers, antioxidants, viscosity modifiers, surface tension modifiers, dispersants, dispersion stabilizers, antifungal agents, rust inhibitors, pH adjusters, antifoaming agents, chelating agents, and the like. The ink composition can be appropriately selected and used in an appropriate amount. These functional components include a single compound that can exhibit one or more functions. Therefore, in the following blending ratio of the functional component, the handling of the functional component in the case where the function is duplicated shall include the compound in each functional component independently.

  The drying inhibitor used in the present invention is preferably a water-soluble organic solvent having a vapor pressure lower than that of water. Specific examples include ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, thiodiglycol, dithiodiglycol, 2-methyl-1,3-propanediol, 1,2,6-hexanetriol, acetylene glycol derivatives, glycerin. Polyhydric alcohols typified by trimethylolpropane, etc., lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, triethylene glycol monoethyl (or butyl) ether 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, heterocycles such as N-ethylmorpholine, sulfolane, dimethyl sulfoxide, - sulfur-containing compounds such as sulfolane, diacetone alcohol, polyfunctional compounds such as diethanolamine, and urea derivatives. Of these, polyhydric alcohols such as glycerin and diethylene glycol are more preferred. Moreover, said drying inhibitor may be used independently and may be used together 2 or more types. These drying inhibitors are preferably contained in the ink composition in an amount of 10 to 50% by mass.

  Examples of penetration enhancers used in the present invention include alcohols such as ethanol, isopropanol, butanol, di (tri) ethylene glycol monobutyl ether, 1,2-hexanediol, sodium lauryl sulfate, sodium oleate, and nonionic surfactants. Etc. can be used. If these are contained in the ink composition in an amount of 10 to 30% by mass, sufficient effects are obtained, and it is preferable to use them in a range of addition amounts that do not cause printing bleeding or paper loss (print-through).

  Examples of the ultraviolet absorber used for improving the storability of the image in the present invention include JP-A Nos. 58-185677, 61-190537, JP-A-2-782, and JP-A-5-97075. Benzotriazole compounds described in JP-A-9-34057, etc., benzophenone compounds described in JP-A No. 46-2784, JP-A No. 5-194443, US Pat. No. 3,214,463, etc. 48-30492, 56-21114, and cinnamic acid compounds described in JP-A-10-88106, JP-A-4-298503, JP-A-8-53427, and 8-239368. And triazine compounds described in JP-A-10-182621, JP-A-8-501291, etc. Jar No. Compounds described in No. 24239, compounds that emit fluorescence by absorbing ultraviolet rays typified by stilbene-based compounds and benzoxazole-based compounds, so-called fluorescent brighteners, can also be used.

  In the present invention, various organic and metal complex anti-fading agents can be used as the antioxidant used to improve image storage stability. Organic anti-fading agents include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, heterocycles, etc. Complex, zinc complex and the like. More specifically, Research Disclosure No. No. 17643, No. VII, I to J, ibid. 15162, ibid. No. 18716, page 650, left column, ibid. No. 36544, page 527, ibid. No. 307105, page 872, ibid. The compounds described in the patent cited in No. 15162 and the compounds included in the general formulas and compound examples of the representative compounds described in pages 127 to 137 of JP-A-62-215272 can be used.

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

The conductivity of the ink composition of the present invention is in the range of 0.01 to 10 S / m. Among these, a preferable range is a conductivity of 0.05 to 5 S / m.
The conductivity can be measured by an electrode method using commercially available saturated potassium chloride.
The conductivity can be controlled mainly by the ion concentration in the aqueous solution. When the salt concentration is high, desalting can be performed using an ultrafiltration membrane or the like. Moreover, when adjusting conductivity by adding salt etc., it can adjust by adding various organic substance salt and inorganic substance salt.
Inorganic salts include potassium halide, sodium halide, sodium sulfate, potassium sulfate, sodium hydrogen sulfate, potassium hydrogen sulfate, sodium nitrate, potassium nitrate, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium phosphate, sodium monohydrogen phosphate, Inorganic compounds such as boric acid, potassium dihydrogen phosphate, sodium dihydrogen phosphate, sodium acetate, potassium acetate, potassium tartrate, sodium tartrate, sodium benzoate, potassium benzoate, sodium p-toluenesulfonate, potassium saccharinate Organic compounds such as potassium phthalate and sodium picolinate can also be used.
The conductivity can also be adjusted by selecting the components of the aqueous medium described later.

The viscosity of the ink composition of the present invention is preferably 1 to 30 mPa · s at 25 ° C. More preferably, it is 2-15 mPa * s, Most preferably, it is 2-10 mPa * s. If it exceeds 30 mPa · s, the fixing speed of the recorded image becomes slow, and the discharge performance also deteriorates. If it is less than 1 mPa · s, the recorded image is blurred and the quality is lowered.
The viscosity can be arbitrarily adjusted by adding the ink solvent. Examples of the ink solvent include glycerin, diethylene glycol, triethanolamine, 2-pyrrolidone, diethylene glycol monobutyl ether, and triethylene glycol monobutyl ether.
A viscosity modifier may be used. Examples of the viscosity modifier include water-soluble polymers such as celluloses and polyvinyl alcohol, and nonionic surfactants. In more detail, “Viscosity Preparation Technology” (Technical Information Association, 1999), Chapter 9, and “Chemicals for Inkjet Printers (98 Supplement)-Material Development Trends and Prospects Survey” (CMC, 1997) 162- Page 174.

  The method for measuring the viscosity of the liquid is described in detail in JIS Z8803, but can be easily measured with a commercially available viscometer. For example, the rotary type includes Tokyo Keiki B-type viscometer and E-type viscometer. In this invention, it measured at 25 degreeC by the vibration type VM-100AL type of Yamaichi Electric. The unit of viscosity is Pascal second (Pa · s), but millipascal second (mPa · s) is usually used.

The surface tension of the ink composition used in the present invention is preferably 20 to 50 mN / m, more preferably 20 to 40 mN / m at 25 ° C. for both dynamic and static surface tension. If the surface tension exceeds 50 mN / m, the ejection quality, bleeding at the time of color mixing, print quality such as whiskers, etc. will be significantly reduced. In addition, when the surface tension of the ink composition is 20 mN / m or less, there may be a printing defect due to adhesion of the ink composition to the hard surface during ejection.
For the purpose of adjusting the surface tension, various cations, anions, nonionic surfactants and betaine surfactants can be added. Moreover, 2 or more types of surfactant can be used together.

As a static surface tension measuring method, a capillary rising method, a dropping method, a hanging ring method and the like are known. In the present invention, a vertical plate method is used as a static surface tension measuring method.
When a thin plate of glass or platinum is partially immersed in the liquid and hung vertically, the surface tension of the liquid acts downward along the length of contact between the liquid and the plate. The surface tension can be measured by balancing this force with an upward force.

  Examples of the dynamic surface tension measurement method include “New Experimental Chemistry Course, Vol. 18, Interface and Colloid” [Maruzen Co., Ltd., p. 69-90 (1977)], the vibration jet method, the meniscus dropping method, the maximum bubble pressure method and the like are known, and further, the liquid film destruction as described in JP-A-3-2064 is known. In the present invention, a bubble pressure differential pressure method is used as a dynamic surface tension measurement method. The measurement principle and method will be described below.

  When bubbles are generated in the solution that has become homogeneous by stirring, a new gas-liquid interface is generated, and the surfactant molecules in the solution gather on the surface of the water at a constant rate. When the bubble rate (bubble generation rate) is changed, if the generation rate slows down, more surfactant molecules gather on the surface of the bubble, so the maximum bubble pressure just before the bubble pops is reduced, The maximum bubble pressure (surface tension) relative to the bubble rate can be detected. As a preferable dynamic surface tension measurement, a method is used in which bubbles are generated in a solution using two large and small probes, the differential pressure in the maximum bubble pressure state of the two probes is measured, and the dynamic surface tension is calculated. Can be mentioned.

The non-volatile component in the ink composition of the present invention is 10 to 70% by mass of the total amount of the ink composition. The ejection stability of the ink composition, print image quality, various image fastnesses, and It is preferable from the viewpoint of bleeding and stickiness reduction on the printing surface, and is more preferably 20 to 60% by mass from the viewpoint of ejection stability of the ink composition and reduction of bleeding of the image after printing.
Here, the non-volatile component means a liquid, a solid component or a high molecular weight component having a boiling point of 150 ° C. or higher under 1 atm. Non-volatile components of ink-jet ink compositions are dyes, high-boiling solvents, polymer latex added as necessary, surfactants, dye stabilizers, antifungal agents, buffering agents, etc., and many of these non-volatile components Reduces the dispersion stability of the ink composition other than the dye stabilizer and also remains on the inkjet image-receiving paper after printing. And has the property of exacerbating image bleeding under high humidity conditions.

  In the present invention, a high molecular weight compound can also be contained. Here, the high molecular weight compound means all high molecular compounds having a number average molecular weight of 5000 or more contained in the ink composition. These polymer compounds are soluble in water-soluble polymer compounds that are substantially soluble in aqueous media, water-dispersible polymer compounds such as polymer latex and polymer emulsion, and polyhydric alcohols that are used as auxiliary solvents. Alcohol-soluble polymer compounds and the like can be mentioned, and any compound that can be dissolved or dispersed substantially uniformly in the ink composition is included in the polymer compound of the present invention.

Specific examples of the water-soluble polymer compound include polyvinyl alcohol, silanol-modified polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl pyrrolidone, polyethylene oxide, water-soluble polymers such as polyoxyalkylene oxide such as polypropylene oxide, and polyalkylene oxide derivatives. polysaccharides, starch, cationized starch, casein, natural water-soluble polymers such as gelatin, polyacrylic acid, polyacrylamide or aqueous acrylic resins such as a copolymer thereof, aqueous alkyd resins, -SO in the molecule ₃ ^-, Examples thereof include water-soluble polymer compounds having a —COO 2 ^— group and substantially soluble in an aqueous medium.
Examples of the polymer latex include styrene-butadiene latex, styrene-acrylic latex, and polyurethane latex. Furthermore, an acrylic emulsion etc. are mentioned as a polymer emulsion.
These water-soluble polymer compounds can be used alone or in combination of two or more.

As described above, the water-soluble polymer compound is used as a viscosity modifier to adjust the viscosity of the ink composition in a viscosity region having good ejection characteristics. As the viscosity increases, the ejection stability of the ink composition decreases, and the nozzle becomes easily clogged by precipitates as the ink composition ages.
The addition amount of the polymer compound of the viscosity modifier depends on the molecular weight of the compound to be added (the higher the molecular weight, the smaller the addition amount may be), but the addition amount is 0 to 5% by mass with respect to the total amount of the ink composition. The content is preferably 0 to 3% by mass, more preferably 0 to 1% by mass.

  Further, in the present invention, the above-mentioned cation, anion, nonionic and betaine surfactants are necessary as a dispersant and dispersion stabilizer, and fluorine-based, silicone-based compounds and chelating agents represented by EDTA are required as an antifoaming agent. Can be used according to.

The reflection type medium that is a printing medium preferably used in the present invention will be further described. Examples of reflective media include recording paper and recording film. Supports for recording paper and recording film are made of chemical pulp such as LBKP and NBKP, mechanical pulp such as GP, PGW, RMP, TMP, CTMP, CMP, CGP, and waste paper pulp such as DIP. Additives such as known pigments, binders, sizing agents, fixing agents, cationic agents, paper strength enhancers, etc. can be mixed and manufactured using various devices such as long net paper machines and circular net paper machines. is there. As the support, in addition to these supports, either synthetic paper or plastic film sheet may be used. The thickness of the support is preferably 10 to 250 μm and the basis weight is preferably 10 to 250 g / m 2.
An image receiving layer and a back coat layer may be provided on the support as they are to provide an image receiving material for the ink composition and the ink set of the present invention, or after a size press or anchor coat layer is provided with starch, polyvinyl alcohol or the like, the image receiving layer and A back coat layer may be provided as an image receiving material. Further, the support may be flattened by a calendar device such as a machine calendar, a TG calendar, or a soft calendar.
As the support, paper and plastic film laminated on both sides with polyolefin (eg, polyethylene, polystyrene, polybutene and copolymers thereof) or polyethylene terephthalate are more preferably used. It is preferable to add a white pigment (eg, titanium oxide, zinc oxide) or a tinting dye (eg, cobalt blue, ultramarine blue, neodymium oxide) to the polyolefin.

  The image receiving layer provided on the support contains a porous material and an aqueous binder. The image receiving layer preferably contains a pigment, and the pigment is preferably a white pigment. White pigments include calcium carbonate, kaolin, talc, clay, diatomaceous earth, synthetic amorphous silica, aluminum silicate, magnesium silicate, calcium silicate, aluminum hydroxide, alumina, lithopone, zeolite, barium sulfate, calcium sulfate, titanium dioxide, Examples thereof include inorganic white pigments such as zinc sulfide and zinc carbonate, organic pigments such as styrene pigments, acrylic pigments, urea resins and melamine resins. A porous white inorganic pigment is particularly preferable, and synthetic amorphous silica having a large pore area is particularly preferable. As the synthetic amorphous silica, either anhydrous silicic acid obtained by a dry production method (gas phase method) or hydrous silicic acid obtained by a wet production method can be used.

  Specific examples of the recording paper containing the pigment in the image receiving layer include JP-A Nos. 10-81064, 10-119423, 10-157277, 10-217601, 11-348409, and JP-A-2001-138621. 2000-43401, 2000-2111235, 2000-309157, 2001-96897, 2001-138627, JP-A-11-91242, 8-2087, 8-2090, 8-2091, 8-9. 2093, 8-174992, 11-192777, JP-A-2001-301314, and the like can be used.

  The aqueous binder contained in the image receiving layer includes water-soluble polyvinyl alcohol, silanol-modified polyvinyl alcohol, starch, cationized starch, casein, gelatin, carboxymethylcellulose, hydroxyethylcellulose, polyvinylpyrrolidone, polyalkylene oxide, polyalkylene oxide derivatives, etc. Examples thereof include water-dispersible polymers such as polymers, styrene butadiene latexes, and acrylic emulsions. These aqueous binders can be used alone or in combination of two or more. In the present invention, among these, polyvinyl alcohol and silanol-modified polyvinyl alcohol are particularly preferable in terms of adhesion to the pigment and resistance to peeling of the ink receiving layer.

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

The mordant added to the image receiving layer is preferably immobilized. For that purpose, a polymer mordant is preferably used.
For the polymer mordant, JP-A-48-28325, 54-74430, 54-124726, 55-22766, 55-142339, 60-23850, 60-23835, 60-23852, 60-23853, 60-57836, 60-60643, 60-118834, 60-122940, 60-122941, 60-122942, 60- No. 235134, JP-A-1-161236, U.S. Pat.Nos. 2,484,430, 2,548,564, 3,148,061, 3,309,690, 4,115,124, 4,124,386, 4,193,800, 4,283,853, 4,282,305, It is described in each specification of the same No. 4450224. An image receiving material containing a polymer mordant described in JP-A-1-161236, pages 212 to 215 is particularly preferred. When the polymer mordant described in the publication is used, an image with excellent image quality is obtained and the light resistance of the image is improved.

  The water-proofing agent is effective for making the image water-resistant. As these water-proofing agents, cationic resins are particularly desirable. Examples of such a cationic resin include polyamide polyamine epichlorohydrin, polyethyleneimine, polyamine sulfone, dimethyldiallylammonium chloride polymer, and cationic polyacrylamide. The content of these cationic resins is preferably 1 to 15% by mass, particularly 3 to 10% by mass, based on the total solid content of the ink receiving layer.

Examples of the light resistance improver and gas resistance improver include phenol compounds, hindered phenol compounds, thioether compounds, thiourea compounds, thiocyanate compounds, amine compounds, hindered amine compounds, TEMPO compounds, hydrazine compounds, hydrazide compounds, amidine compounds, Vinyl group-containing compounds, ester compounds, amide compounds, ether compounds, alcohol compounds, sulfinic acid compounds, saccharides, water-soluble reducing compounds, organic acids, inorganic acids, hydroxy group-containing organic acids, benzotriazole compounds, benzophenone compounds, triazine compounds , Heterocyclic compounds, water-soluble metal salts, organometallic compounds, metal complexes and the like.
Specific examples of these compounds include JP-A-10-182621, JP-A-2001-260519, JP-A-2000-260519, JP-B-4-34953, JP-B-4-34513, and JP-B-4-34512. , JP-A-11-170686, JP-A-60-67190, JP-A-7-276808, JP-A-2000-94829, JP-T 8-512258, JP-A-11-321090, etc. Can be given.

The surfactant functions as a coating aid, a peelability improver, a slippage improver or an antistatic agent. The surfactant is described in JP-A Nos. 62-173463 and 62-183457.
An organic fluoro compound may be used in place of the surfactant. The organic fluoro compound is preferably hydrophobic. Examples of the organic fluoro compound include a fluorine-based surfactant, an oily fluorine-based compound (eg, fluorine oil), and a solid fluorine compound resin (eg, tetrafluoroethylene resin). The organic fluoro compounds are described in JP-B-57-9053 (columns 8 to 17), JP-A-61-20994, and 62-135826.

  As the hardener, materials described in JP-A-1-161236, page 222, JP-A-9-263036, JP-A-10-119423, and JP-A-2001-310547 can be used.

  Examples of other additives to be added to the image receiving layer include pigment dispersants, thickeners, antifoaming agents, dyes, fluorescent whitening agents, preservatives, pH adjusters, and matting agents. The ink receiving layer may be one layer or two layers.

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

  As the aqueous binder contained in the backcoat layer, styrene / maleate copolymer, styrene / acrylate copolymer, polyvinyl alcohol, silanol modified polyvinyl alcohol, starch, cationized starch, casein, gelatin, carboxymethylcellulose Water-soluble polymers such as hydroxyethyl cellulose and polyvinyl pyrrolidone, and water-dispersible polymers such as styrene butadiene latex and acrylic emulsion. Examples of other components contained in the backcoat layer include an antifoaming agent, an antifoaming agent, a dye, a fluorescent brightening agent, a preservative, and a water-proofing agent.

  A polymer fine particle dispersion may be added to the constituent layers (including the back layer) of the inkjet recording paper and recording film. The polymer fine particle dispersion is used for the purpose of improving the physical properties of the film such as dimensional stabilization, curling prevention, adhesion prevention, and film cracking prevention. The polymer fine particle dispersion is described in JP-A Nos. 62-245258, 62-136648, and 62-110066. When a polymer fine particle dispersion having a low glass transition temperature (40 ° C. or lower) is added to a layer containing a mordant, cracking and curling of the layer can be prevented. Further, even when a polymer fine particle dispersion having a high glass transition temperature is added to the back layer, curling can be prevented.

  The ink composition of the present invention can also be used for purposes other than inkjet recording. For example, it can be used for display image materials, image forming materials for interior decoration materials, and image forming materials for outdoor decoration materials.

  Display image materials include posters, wallpaper, small decorative items (such as figurines and dolls), commercial flyers, wrapping paper, wrapping materials, paper bags, plastic bags, packaging materials, signs, transportation (automobiles, buses, trains, etc.) ) Refers to various things such as images drawn and attached to the side, clothes with logos, and so on. When the dye of the present invention is used as a material for forming a display image, the image includes all patterns of dyes that can be recognized by humans, such as abstract designs, characters, and geometric patterns, in addition to images in a narrow sense.

  The interior decoration material refers to various items such as wallpaper, decorative accessories (such as figurines and dolls), lighting fixture members, furniture members, floor and ceiling design members. When the dye of the present invention is used as an image forming material, the image includes all patterns of dyes that can be recognized by humans such as abstract designs, characters, and geometric patterns in addition to images in a narrow sense.

  The outdoor decoration material refers to various materials such as wall materials, roofing materials, signboards, gardening materials, outdoor decoration accessories (such as figurines and dolls), and members of outdoor lighting equipment. When the dye of the present invention is used as an image forming material, the image includes not only images in a narrow sense but also all patterns of dyes that can be recognized by humans, such as abstract designs, characters, and geometric patterns.

  In the above applications, examples of media on which a pattern is formed include various materials such as paper, fiber, cloth (including non-woven fabric), plastic, metal, and ceramics. As the dyeing form, the dye can be fixed in the form of mordanting, printing, or a reactive dye having a reactive group introduced. Among these, it is preferable that the mordanting is performed.

In the production of an ink stock solution or an ink composition, ultrasonic vibration can be applied to the dissolution step of additives such as dyes.
Ultrasonic vibration means that ultrasonic energy equal to or higher than the energy received by the recording head is preliminarily applied during the manufacturing process of the ink composition in order to prevent the ink composition from generating bubbles due to the pressure applied by the recording head. In addition to removing bubbles.
The ultrasonic vibration is usually an ultrasonic wave having a frequency of 20 kHz or higher, preferably 40 kHz or higher, more preferably 50 kHz. The energy applied to the liquid by ultrasonic vibration is usually 2 × 10 ⁷ J / m ³ or more, preferably 5 × 10 ⁷ J / m ³ or more, more preferably 1 × 10 ⁸ J / m ³ or more. . Further, the application time of ultrasonic vibration is usually about 10 minutes to 1 hour.
The step of applying ultrasonic vibration shows an effect at any time after the dye is put into the medium. Even if ultrasonic vibration is applied after the completed ink composition is stored once, the effect is exhibited. However, adding ultrasonic vibration when dissolving and / or dispersing the dye in the medium has a greater effect of removing bubbles, and the ultrasonic vibration promotes dissolution and / or dispersion of the dye in the medium. Therefore, it is preferable.
That is, the step of applying at least ultrasonic vibration can be performed in any case, either during or after the step of dissolving and / or dispersing the dye in the medium. In other words, the step of applying at least ultrasonic vibration can be arbitrarily performed once or more after the ink composition is prepared until it becomes a product.
As an embodiment, the step of dissolving and / or dispersing in the medium preferably includes a step of dissolving the dye in a medium of a part of the whole medium and a step of mixing the remaining medium, and at least one of the above It is preferable to apply ultrasonic vibration to this step, and it is more preferable to apply at least ultrasonic vibration to the step of dissolving the dye in a part of the medium.
The step of mixing the remaining solvent may be a single step or a plurality of steps.
In addition, it is preferable to use heat degassing or vacuum degassing in combination with the production of the ink composition according to the present invention because the effect of removing bubbles in the ink composition is improved. The heating degassing step or the vacuum degassing step is preferably performed simultaneously with or after the step of mixing the remaining medium.
Examples of the ultrasonic vibration generating means in the step of applying ultrasonic vibration include known devices such as an ultrasonic disperser.

When preparing the ink stock solution or ink composition of the present invention, a step of removing dust which is a solid content by filtration, which is performed after further preparation, is important. A filtration filter is used for this work. The filtration filter at this time is a filter having an effective diameter of 1 μm or less, preferably 0.3 μm or less and 0.05 μm or more, particularly preferably 0.3 μm or less and 0.25 μm or more. Use. Various materials can be used as the filter material, but in the case of an ink composition of a water-soluble dye, it is preferable to use a filter prepared for an aqueous solvent. Among them, it is particularly preferable to use a filter made of a polymer material that hardly generates dust. As the filtration method, the solution may be passed through a solution, and either pressure filtration or vacuum filtration can be used.
After this filtration, air is often taken into the solution. Since bubbles caused by air often cause image disturbance in ink jet recording, it is preferable to separately provide the aforementioned defoaming step. As the defoaming method, the filtered solution may be allowed to stand, or various methods such as ultrasonic defoaming and vacuum defoaming using a commercially available apparatus can be used. In the case of defoaming with ultrasonic waves, the defoaming operation is preferably performed for about 30 seconds to 2 hours, more preferably about 5 minutes to 1 hour.
These operations are preferably performed using a space such as a clean room or a clean bench in order to prevent dust from entering during the operation. In the present invention, it is particularly preferable to perform this operation in a space of class 1000 or less as the cleanliness. Here, “cleanness” refers to a value measured by a dust counter.

  The droplet ejection volume of the ink composition on the recording material in the invention is from 0.1 pl to 100 pl. A preferable range of the droplet ejection volume is 0.5 pl or more and 50 pl or less, and a particularly preferable range is 2 pl or more and 50 pl or less.

[Inkjet recording method, ink cartridge for inkjet recording, inkjet recording apparatus and inkjet recorded matter]
The inkjet recording method of the present invention is a method for forming a colored image (sometimes simply referred to as an image) on a recording material (recording material) using an inkjet recording ink.
In the present invention, there is no limitation on the ink jet recording method as long as the image recording is performed by an ink jet printer using the ink composition or ink set of the present invention, and a known method such as electrostatic attraction is used. The charge control method for discharging the ink composition, the drop-on-demand method (pressure pulse method) that uses the vibration pressure of the piezo element, the electrical signal is converted into an acoustic beam, and the ink composition is irradiated and the radiation pressure is used. It is used in acoustic ink jet systems that eject ink compositions, thermal ink jet (bubble jet (registered trademark)) systems that use the pressure generated by heating the ink composition to form bubbles.
Inkjet recording methods include a method of ejecting a large number of low-density ink compositions called photo inks in a small volume, a method of improving image quality using a plurality of ink compositions having substantially the same hue and different concentrations, and colorless and transparent. The method using the ink composition is included. The droplet ejection volume of the ink composition is mainly controlled by the print head.

For example, in the case of the thermal ink jet method, the droplet ejection volume can be controlled by the structure of the print head. That is, droplets can be ejected in a desired size by changing the sizes of the ink chamber, the heating unit, and the nozzle. Even in the case of the thermal ink jet method, it is possible to realize droplet ejection of a plurality of sizes by providing a plurality of print heads having different heating parts and nozzle sizes.
In the case of the drop-on-demand method using a piezo element, the droplet ejection volume can be changed due to the structure of the print head as in the thermal ink jet method, but the waveform of the drive signal that drives the piezo element is controlled as described later. By doing so, droplets of a plurality of sizes can be ejected with a print head having the same structure.

The ejection frequency when the ink composition of the present invention is ejected onto a recording material is preferably 1 KHz or more.
In order to record a high-quality image such as a photograph, it is necessary to set the droplet ejection density to 600 dpi (number of dots per inch) or more in order to reproduce a sharp image with small ink droplets.
On the other hand, when the ink composition is ejected by a head having a plurality of nozzles, the number of heads that can be driven simultaneously is about several tens to 200 in the type in which the recording paper and the head are moved and recorded in directions orthogonal to each other. There is a restriction that the number of heads called line heads is fixed even in the hundreds. This is because there are restrictions on driving power, and heat generated by the head affects the image, so that a large number of head nozzles cannot be driven simultaneously.
Here, the recording speed can be increased by increasing the drive frequency.
In the case of the thermal ink jet method, the droplet ejection frequency can be controlled by controlling the frequency of the head drive signal for heating the head.
In the case of the piezo method, this is possible by controlling the frequency of a signal for driving the piezo.
The driving of the piezo head will be described. For the image signal to be printed, the droplet size, droplet ejection speed, and droplet ejection frequency are determined by the printer control unit, and a signal for driving the print head is created. The drive signal is supplied to the print head. The droplet ejection size, droplet ejection speed, and droplet ejection frequency are controlled by a signal for driving the piezo. Here, the droplet ejection size and droplet ejection speed are determined by the shape and amplitude of the drive waveform, and the frequency is determined by the signal repetition period.
When this droplet ejection frequency is set to 10 kHz, the head is driven every 100 microseconds, and recording of one line is completed in 400 microseconds. By setting the moving speed of the recording paper to move 1/600 inch in 400 microseconds, that is, approximately 42 microns, it is possible to print at a speed of one sheet in 1.2 seconds.

As for the configuration of the printing apparatus and the printer used in the present invention, for example, a mode as disclosed in JP-A-11-170527 is preferable. For the ink cartridge, for example, the one disclosed in Japanese Patent Laid-Open No. 5-229133 is suitable. With respect to the suction and the configuration of a cap or the like that covers the print head at that time, for example, the one disclosed in JP-A-7-276671 is preferable. Further, it is preferable that a filter for eliminating bubbles as disclosed in JP-A-9-277552 is provided in the vicinity of the head.
The surface of the nozzle is preferably subjected to water repellent treatment as described in JP-A-2002-292878. The application may be a printer connected to a computer or an apparatus specialized for printing photographs.
In the ink jet recording method applied to the present invention, it is preferable that the average droplet ejection speed when ejecting the ink composition onto a recording material is 2 m / sec or more, preferably 5 m / sec or more.
The droplet ejection speed is controlled by controlling the shape and amplitude of the waveform that drives the head.
In addition, by using a plurality of drive waveforms properly, it is possible to eject droplets of a plurality of sizes with the same head.

Hereinafter, a recording paper and a recording film used for ink jet printing using the ink of the present invention will be described.
The support in recording paper and recording film is made of chemical pulp such as LBKP and NBKP, mechanical pulp such as GP, PGW, RMP, TMP, CTMP, CMPMP, CGP, and waste paper pulp such as DIP. Additives such as known pigments, binders, sizing agents, fixing agents, cationic agents, paper strength enhancers, etc. can be mixed and manufactured using various devices such as long net paper machines and circular net paper machines. is there. In addition to these supports, either synthetic paper or plastic film sheet may be used, and the thickness of the support is preferably 10 to 250 μm and the basis weight is preferably 10 to 250 g / m ² . The support may be provided with an ink receiving layer and a backcoat layer as they are, or after a size press or anchor coat layer is provided with starch, polyvinyl alcohol or the like, an ink receiving layer and a backcoat layer may be provided. Further, the support may be flattened by a calendar device such as a machine calendar, a TG calendar, or a soft calendar. In the present invention, as the support, paper and plastic films laminated on both sides with polyolefin (for example, polyethylene, polystyrene, polyethylene terephthalate, polybutene and copolymers thereof) are more preferably used. It is preferable to add a white pigment (for example, titanium oxide or zinc oxide) or a tinting dye (for example, cobalt blue, ultramarine blue, or neodymium oxide) to the polyolefin.

  The ink jet recorded matter of the present invention is formed by forming a colored image on a recording material using the above-described ink for ink jet recording of the present invention. Here, the image formation can be suitably obtained by adopting an ink jet recording method using the above-described ink jet recording apparatus.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples at all. In the examples, “parts” represents parts by mass.

  The present invention will be described more specifically with reference to the following examples. The materials, reagents, ratios, equipment, operations, and the like shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. In the following examples, “%” and “parts” represent “% by mass” and “parts by mass” unless otherwise specified, and the molecular weight indicates the mass average molecular weight.

[Synthesis Example 1]
A synthesis scheme of DYE-11 is shown below.

(1) Synthesis of intermediate (B-11):
To 94.3 g of intermediate (A-11), 102 g of ammonium acetate and 83 mL of ethyl acetoacetate were added, heated to an internal temperature of 80 ° C., and stirred for 2 hours. After cooling to an internal temperature of 40 ° C., 150 mL of ethanol and 150 mL of diethyl ether were added, filtered, and washed with 100 mL of ethanol and 100 mL of diethyl ether. The obtained solid was suspended in 900 mL of water, 670 mL of 1M aqueous potassium hydroxide solution was added, and the mixture was stirred for 20 minutes. 12N aqueous hydrochloric acid was added to adjust the pH to 6.4, and the mixture was stirred at room temperature for 30 minutes. The precipitated crystals were separated by filtration. After washing with 1 L of water, drying at 70 ° C. yielded 126.6 g of white crystals of intermediate (B-11).

(2) Synthesis of intermediate (C-11):
To 60 g of the intermediate (B-11), 100.2 mL of phosphorus oxychloride and 37.5 mL of triethylamine were added, and the temperature was raised to an internal temperature of 80. After stirring at the same temperature for 2 hours, the reaction solution was cooled to an internal temperature of 25 ° C. Separately, 1.6 L of water having an internal temperature of 25 ° C. was prepared, and the above reaction solution was added in portions so that the internal temperature was 25 ° C. to 30 ° C. After completion of the addition, the mixture was stirred at an internal temperature of 25 ° C. for 30 minutes, and then an 8N aqueous sodium hydroxide solution was added at 25 ° C. to 30 ° C. to adjust the pH to 0.5. The precipitated crystals were separated by filtration and washed with 100 mL of water. It dried under reduced pressure at room temperature to obtain 53.5 g of yellowish green crystals of intermediate (C-11).

(3) Synthesis of intermediate (D-11):
16 mL of aniline was heated to an internal temperature of 90 ° C, and 10 g of intermediate (C-11) was added in portions so that the internal temperature was 130 ° C or lower. After completion of the addition, the mixture was stirred at 100 ° C. for 30 minutes and cooled to an internal temperature of 25 ° C. Isopropyl alcohol 50mL was added and it stirred at the internal temperature of 75 degreeC for 1 hour. After cooling to an internal temperature of 25 ° C., the precipitated crystals were separated by filtration and washed with 50 mL of water and 30 mL of acetonitrile. The obtained crystals were suspended in 50 mL of acetonitrile and cooled to an internal temperature of 5 ° C. 11.1 mL of chlorosulfonic acid was added dropwise over 20 minutes so that the internal temperature was 15 ° C. or lower. After completion of dropping, the mixture was stirred for 15 minutes at an internal temperature of 10 ° C., then heated to 25 ° C. over 10 minutes, and stirred at the same temperature for 1 hour to obtain a reaction solution. Separately, 50 mL of water was cooled to an internal temperature of 5 ° C., and the above reaction solution was added dropwise thereto so that the internal temperature was 15 ° C. or lower. After stirring for 30 minutes at an internal temperature of 10 ° C., the precipitated crystals are separated by filtration, washed with 50 mL of water and 30 mL of acetonitrile, dried at 50 ° C., and pale yellow crystals of intermediate (D-11) 13. 3 g was obtained.

(4) Synthesis of intermediate (B-1):
40 g of raw material (A-1; Wako Pure Chemicals) was added to 12.5 g of thiourea and 120 ml of water, and stirred at 70 ° C. for 5 hours. The precipitated crystals were separated by filtration, 400 ml of 5% NaOH solution was added, and the mixture was stirred at room temperature for 3 hours and then filtered to obtain 35.5 g of yellow crystals of intermediate (B-11).

(5) Synthesis of intermediate (C-1):
57.0 g of reduced iron, 5.0 g of ammonium chloride, 35 ml of water and 250 ml of isopropyl alcohol were refluxed for 30 minutes, 22.0 g of intermediate (B-1) was added, and the mixture was stirred at reflux for 1 hour. After filtration, the filtrate was concentrated to obtain 15.0 g of yellow crystals of intermediate (C-1).

(6) Synthesis of Intermediate (D-1) 9.6 g of Intermediate (C-1) was added to 125 mL of acetone and stirred at an internal temperature of 50 ° C. for dissolution. After cooling the internal temperature to 4 ° C. in an ice bath, 5.6 g of acetic anhydride was added dropwise over 15 minutes. After raising the temperature to room temperature, 50 mL of water was added, and acetone was distilled off under reduced pressure. The crystals were separated by filtration, washed twice with 50 mL of water, and dried at 80 ° C. for 6 hours to obtain 9.9 g of intermediate (D-1) white crystals.

(7) Synthesis of Intermediate (F-1) 4.3 g of Intermediate (E-1) was added to 43 mL of water and stirred at room temperature. After dropwise addition of 4.0 mL of 12N hydrochloric acid, the internal temperature was cooled to 4 ° C. Thereto was added dropwise 3 mL of an aqueous solution of 0.9 g of sodium nitrite, and the mixture was stirred at 5 ° C. or lower for 2 hours. Thereafter, 0.1 g of urea was added and stirred at an internal temperature of 4 ° C. for 15 minutes to obtain a diazonium solution.
Separately, 2.4 g of intermediate (D-1) and 8.6 g of lithium acetate were dissolved in 55 mL of methanol and 3.5 mL of dimethylacetamide and cooled to an internal temperature of 5 ° C. or lower. The diazonium solution was added dropwise at an internal temperature of 5 ° C. or less over 5 minutes. After stirring for 1.5 hours, 15.0 g of lithium chloride was added, followed by dropwise addition of 150 mL of isopropyl alcohol. The crystals were separated by filtration and washed with 100 mL of isopropyl alcohol. After drying at 80 ° C., 5.4 g of brown crystals of intermediate (F-1) were obtained.

(8) Synthesis of DYE-11 Intermediate (F-11) (2.5 g) was added to phosphoric acid (10 mL) and stirred at an internal temperature of 40 ° C. for 30 minutes for complete dissolution. Thereafter, the internal temperature was cooled to 3 ° C., and 1.35 g of a 43 wt% sulfuric acid solution of nitrosyl sulfuric acid was added dropwise over 2 minutes so as to keep the internal temperature at 5 ° C. or less. The mixture was stirred at an internal temperature of 5 ° C. for 1 hour to obtain a diazonium salt solution. Separately, 1.3 g of the intermediate (D-11) was dissolved in a mixed solvent of 20 mL of methanol and 20 mL of dimethylacetamide, and cooled with ice to cool the internal temperature to 5 ° C. To this solution, the above-described diazonium salt solution was added in portions so that the internal temperature was 10 ° C. or less, and stirred at an internal temperature of 5 ° C. for 2 hours. Then, 30 g of lithium chloride and 60 mL of isopropyl alcohol were added and left for 12 hours. did. The crystals were separated by filtration and washed with 50 mL of isopropyl alcohol. 60 mL of water was added to the crystals, and 250 mL of isopropyl alcohol was added dropwise at room temperature. After the crystals were separated by filtration, 20 mL of water was added, and 4M lithium hydroxide aqueous solution was added to adjust the pH to 8.3. To this solution, 100 mL of isopropyl alcohol was added dropwise, and the precipitated crystals were separated by filtration. The obtained crystals were purified by gel chromatogram (solvent methanol: water = 7: 3) to obtain 0.81 g of green crystals of (DYE-11).

[Synthesis Example 2]
A synthesis scheme of DYE-12 is shown below.

(1) Intermediates (B-1) to (D-1) and (B-11) to (D-11) were synthesized by the method of Synthesis Example 1.

(2) Synthesis of intermediate (D-12) 21.6 mL of chlorosulfonic acid was cooled to an internal temperature of 5 ° C, and 10 g of intermediate (D-11) was added in portions so that the internal temperature was 10 ° C or lower. The reaction solution was obtained by stirring for 5 hours at an internal temperature of 5 ° C. Separately, 180 mL of water was cooled to an internal temperature of 5 ° C., and the above-mentioned reaction solution was added dropwise thereto so that the internal temperature was 15 ° C. or lower. Precipitated crystals were filtered off and washed with water. The obtained crystals were purified by silica gel column chromatography (developing solvent: n-butanol: ethanol: chloroform: water = 4: 4: 2: 3), and 8.98 g of pale yellow crystals of the intermediate (D-12) were obtained. Obtained.

(3) Synthesis of DYE-12 Intermediate (F-11) (2.5 g) was added to phosphoric acid (10 mL) and stirred at an internal temperature of 40 ° C. for 30 minutes for complete dissolution. Thereafter, the internal temperature was cooled to 3 ° C., and 1.35 g of a 43 wt% sulfuric acid solution of nitrosyl sulfuric acid was added dropwise over 2 minutes so as to keep the internal temperature at 5 ° C. or less. The mixture was stirred at an internal temperature of 5 ° C. for 1 hour to obtain a diazonium salt solution. Separately, 1.64 g of the intermediate (D-12) was dissolved in a mixed solvent of 23 mL of methanol and 23 mL of dimethylacetamide, and cooled with ice to cool the internal temperature to 5 ° C. To this solution, the above-described diazonium salt solution was added in portions so that the internal temperature was 10 ° C. or less, and stirred at an internal temperature of 5 ° C. for 2 hours. did. The crystals were separated by filtration and washed with 50 mL of isopropyl alcohol. 60 mL of water was added to the crystals, and 250 mL of isopropyl alcohol was added dropwise at room temperature. After the crystals were separated by filtration, 20 mL of water was added, and 4M lithium hydroxide aqueous solution was added to adjust the pH to 8.3. To this solution, 100 mL of isopropyl alcohol was added dropwise, and the precipitated crystals were separated by filtration. The obtained crystals were purified by gel chromatogram (solvent methanol: water = 7: 3) to obtain 0.68 g of (DYE-12) green crystals.

[Preparation of aqueous solution]
The aqueous solution of the present invention is herein referred to as “ink stock solution”.
[Example-1]
100 g of the compound of the present invention (DYE-11) is dissolved in 900 g of ultrapure water while stirring at room temperature, and then added and dissolved in divided portions. As 0.1 g. Subsequently, unnecessary materials were filtered using a 0.2 μm membrane filter to obtain an ink stock solution-1.

[Example-2]
Except that (DYE-12) was used instead of the compound (DYE-11) of the present invention, the same operation as in Example-1 was performed to obtain an ink stock solution-2.

[Example-3]
After dissolving 0.1 g of lithium hydrogen carbonate in 900 g of ultrapure water at room temperature with stirring, 100 g of the compound of the present invention (DYE-11) was added in portions while stirring at room temperature and dissolved, followed by preservative (Prodexel XL). -2: 0.1 g of Fujifilm Imaging Carrara) was added as a solid content. Subsequently, unnecessary substances were filtered using a 0.2 μm membrane filter to obtain an ink stock solution-3.

[Example-4]
Except that (DYE-12) was used in place of the compound (DYE-11) of the present invention, the same operation as in Example-3 was performed to obtain an ink stock solution-4.

[Comparative Example-1]
Comparative ink stock solution-1 was obtained in the same manner as in Example 1 except that the following compound (DYE-01) was used instead of the compound (DYE-11) of the present invention.

[Comparative Example-2]
Comparative Ink Stock Solution-2 was obtained in the same manner as in Example 1 except that the following compound (DYE-02) was used instead of the compound (DYE-11) of the present invention.

  The above-described ink stock solutions-1 to 4 and comparative ink stock solutions-1 and 2 prepared in Examples-1 to 4 and Comparative Examples-1 to 2 were each stored at 60 ° C for 1 week. The following table shows changes in the liquid properties of the respective ink stock solutions before and after the forced thermal aging test.

  Regarding the change in pH value, the following levels were used based on the pH value immediately after preparation of the ink stock solution (liquid temperature 25 ° C.) and the pH value (liquid temperature 25 ° C.) after the forced thermal aging test (7 days). It was set.

A: Difference in pH value before and after forced thermal aging test is less than 0.3 B: Difference in pH value before and after forced thermal aging test is 0.3 or more and less than 0.5 C: pH value before and after forced thermal aging test The difference in pH is 0.5 or more and less than 0.7 D: The difference in pH value before and after the forced thermal aging test is 0.7 or more

Regarding the ABS value change, the ink stock solution immediately after the ink stock preparation was diluted to 1/5000 with ultrapure water and the ABS (absorbance) value after dilution with forced thermal aging test (7 days), and the ink stock solution was ultrapure to 1/5000. The following levels were set based on the ABS value after dilution with water.
A: Difference in ABS value before and after forced thermal aging test is less than 0.05 B: Difference in ABS value before and after forced thermal aging test is 0.05 or more and less than 0.10 C: ABS value before and after forced thermal aging test Difference is 0.10 or more and less than 0.15 D: ABS value difference before and after forced thermal aging test is 0.15 or more

[Preparation of ink composition]
Based on the composition shown in Table 2 below, each component was stirred at room temperature for 30 minutes, and then the resulting solution was filtered using a membrane filter having an opening of 1.0 μm to obtain each ink composition. In Table 2, the numerical value of each component indicates the weight percent of each component when the mass of the ink composition is 100%, and “remaining” indicating the amount of water is combined with components other than water. The amount is 100% in total.

  In Table 2, as black dyes, compounds represented by the following formulas (BLACK-1) and (BLACK-2) were used as examples of the azo dyes of the present invention. In addition, from the viewpoint of adjusting the hue, compounds represented by the following formulas (YELLOW-1) and (YELLOW-2) were used in combination as complementary color dyes.

  As a comparative example other than the azo dye of the present invention, a compound represented by the following formula (BLACK-3) was used.

  Inkjet printer PM-A700 (manufactured by Seiko Epson Corporation) was used, and Examples 1 to 6 shown in Table 2 (Ink liquids B-01, B-02, B-03, B-04, B-05, B-06) and Comparative Examples 1 to 3 (B-11, B-12 and Ink Cartridge Black; ICBK32), each ink was loaded into a PM-A700 black ink cartridge and used exclusively for inkjet. Recording medium: (1) {Photo paper <gloss> (trade name, manufactured by Seiko Epson Corporation)}, (2) {Photo paper Chrispier <high gloss> (trade name, manufactured by Seiko Epson Corporation)}, (3) {Fuji Film Inkjet Paper “Painting” Photo Finishing Pro (trade name, manufactured by Fuji Photo Film Co., Ltd.)}, (4) {Professional Photo Paper Par PT-101 (trade name, Canon Sales Co., Ltd.)} is printed with an image pattern in which the density changes stepwise so that the OD value is 0.7 to 1.8 (2.0). The properties (light resistance and ozone gas resistance) and image quality (bronze gloss) were evaluated.

[Ozone resistance test method]
The recorded matter was exposed to ozone gas for 7 days under the condition that the ozone gas concentration was set to 5 ppm (25 ° C .; 60% RH). The ozone gas concentration was set using an ozone gas monitor (model: OZG-EM-01) manufactured by APPLICS. The OD value of each color recorded on each printed matter was measured using a reflection densitometer (X-Rite 310TR) at every elapse of a certain period from the start of exposure. The reflection density was measured at three points of 0.7, 1.0, and 1.8 (2.0).

From the obtained results, the optical density residual ratio (ROD) was determined using the following formula: ROD (%) = (D / D ₀ ) × 100. (In the formula, D represents the OD value after the exposure test, and D ₀ represents the OD value before the exposure test.)

Further, based on the results of the above test, the ozone resistance of each color recorded on the recorded matter was ranked A to D using the following criteria.
[Criteria]
Evaluation A: ROD after 7 days from the start of the test is 85% or more at any concentration.
Evaluation B: The ROD after 7 days from the start of the test is such that the concentration at any one point is less than 85%.
Evaluation C: The ROD after 7 days from the start of the test is such that the concentration at any two points is less than 85%.
Evaluation D: ROD after 7 days from the start of the test is less than 85% at all concentrations.

  In this test, a recorded material with little decrease in ROD is excellent even when exposed to ozone for a long time. The obtained results are shown in Table 3.

In addition, from the results of the ozone resistance test for each color, the following criteria were used to rank the ozone resistance of each ink.
[Criteria]
Evaluation A: All the ozone resistance test results are A.
Evaluation B: The ozone resistance test result is B for one of the three reflection densities, and A for the remaining two points.
Evaluation C: The ozone resistance test result is C for one of the three reflection densities, and A or B for the remaining two points.
Evaluation D: The ozone resistance test result is D for one of the three reflection densities.

  In this evaluation, the evaluation A is the best, and then the evaluation B is excellent. The obtained results are shown in Table 3 as “ink resistance to ozone”.

[Light resistance test method]
Using a weather meter (Atlas), the image was irradiated with xenon light (100,000 lux) for 10 days. The OD value of each color recorded on each printed matter was measured using a reflection densitometer (X-Rite 310TR) at every elapse of a certain period from the start of irradiation. The reflection density was measured at three points of 0.7, 1.0, and 1.8 (2.0).

From the obtained results, the optical density residual ratio (ROD) was determined using the following formula: ROD (%) = (D / D ₀ ) × 100.
(In the formula, D represents the OD value after the exposure test, and D ₀ represents the OD value before the exposure test.)

Furthermore, based on the results of the above test, the light resistance of each reflection density recorded on the recorded matter was ranked A to D using the following criteria.
[Criteria]
Evaluation A: ROD 10 days after the start of the test is 85% or more at any concentration.
Evaluation B: The ROD 10 days after the start of the test is such that the concentration at any one point is less than 85%.
Evaluation C: The ROD 10 days after the start of the test is such that the concentration at any two points is less than 85%.
Evaluation D: ROD 10 days after the start of the test is less than 85% at all concentrations.

  In this test, a recorded material with little decrease in ROD even when exposed to light for a long time is excellent. The results obtained are shown in Table 4.

  Further, the following bronze (recorded image quality) evaluation and moisture resistance evaluation were performed.

[Bronze evaluation]
For the inks of Examples 1 and 2, inkjet recording media: (1) {Photo paper <Gloss> (trade name, manufactured by Seiko Epson Corporation)}, (2) {Photo paper Crispia <High gloss> (Product name, Seiko Epson Co., Ltd.)}, (3) {Fuji Film Inkjet Paper “Painting” Photo Finishing Pro (trade name, manufactured by Fuji Photo Film Co., Ltd.)}, (4) {Professional Photo Paper PT-101 (trade name, Canon Sales Co., Ltd.)} is printed with a black color of 1.5 to 2.2 mg per square inch, and the resulting printed matter is printed on a gloss meter (PG-1M, Nippon Denshoku). (Manufactured by Kogyo Co., Ltd.) (measurement angle 60 degrees), and glossiness was determined.
Printing was performed in two environments of 20 ° C. 40% RH and 35 ° C. 60% RH. Using the obtained glossiness and the increased value calculated based on the following formula as a criterion for determining the degree of occurrence of bronze phenomenon, the determination was made based on the following criterion.

Increase value = Glossiness (printed material)-Glossiness (recording medium)

[Criteria]
Evaluation A: Less than 15 Evaluation B: 15 or more and less than 35 Evaluation C: 35 or more and less than 55 Evaluation D: 55 or more

  The obtained results are shown in Table 5 as “bronze gloss”.

Claims (15)

It contains (a) an antiseptic and (b) at least one azo compound represented by the following general formula (1) or a salt thereof, and the content of (b) is 1% by mass to 25% by mass. Aqueous solution.

(In General Formula (1), A represents an aryl group or a nitrogen-containing 5-membered heterocyclic group. G represents a nitrogen atom or —C (R ₂ ) ═. R ₂ represents a hydrogen atom or a sulfo group. group, a carboxy group, _.Y 2, _{Y 3} and _{Y 4} representing a substituted or unsubstituted carbamoyl group, or a cyano group independently, _.Y 2, _{Y 3} represents a hydrogen atom, or a monovalent substituent And Y ₄ may combine with each other to form a ring, M represents a hydrogen atom or a monovalent counter cation, and n represents 0, 1 or 2.)   Furthermore, (c) pH adjuster is contained, The aqueous solution of Claim 1 characterized by the above-mentioned. The aqueous solution according to claim 1 or 2, wherein the azo compound represented by the general formula (1) is an azo compound represented by the following general formula (2).

(In General Formula (2), G represents a nitrogen atom or —C (R ₂ ) ═. R ₂ represents a hydrogen atom, a sulfo group, a carboxy group, a substituted or unsubstituted carbamoyl group, or a cyano group. R ₃ represents a monovalent substituent, A represents an aryl group or a nitrogen-containing 5-membered heterocyclic group, M represents a hydrogen atom or a monovalent counter cation, and n represents 0. Represents 1 or 2.) The azo compound represented by the general formula (1) or (2) is an azo compound represented by the following general formula (3), according to any one of claims 1 to 3. Aqueous solution.

(In General Formula (3), R ₃ represents a monovalent substituent. X ₁ , X ₂ , X ₃ , X ₄ , and X ₅ each independently represents a hydrogen atom or a monovalent substituent. M represents a hydrogen atom or a monovalent counter cation, and n represents 0, 1 or 2. The azo compound represented by the general formula (1) or (2) is an azo compound represented by the following general formula (4). Aqueous solution.

(In General Formula (4), R ₃ represents a monovalent substituent. X ₁ , X ₂ , X ₃ , X ₄ , and X ₅ are each independently a hydrogen atom or a monovalent substituent. M represents a hydrogen atom or a monovalent counter cation, and n represents 0, 1 or 2.)   The aqueous solution according to any one of claims 1 to 5, wherein the azo compound represented by the general formulas (1) to (4) has at least three or more ionic hydrophilic groups.   pH is 7.0-9.0, The aqueous solution of any one of Claims 1-6 characterized by the above-mentioned.   An ink composition comprising the aqueous solution according to claim 1.   An ink for inkjet recording, comprising the aqueous solution according to claim 1.   A colored image is formed on a recording material using the ink for ink jet recording according to claim 9.   An ink cartridge for ink jet recording filled with the ink for ink jet recording according to claim 9.   An ink-jet recorded matter in which a colored image is formed on a recording material using the ink-jet recording ink according to claim 9. An azo compound represented by the following general formula (1) or a salt thereof.

(In General Formula (1), A represents an aryl group or a nitrogen-containing 5-membered heterocyclic group. G represents a nitrogen atom or —C (R ₂ ) ═. R ₂ represents a hydrogen atom, a sulfo group, Y ₂ , Y ₃ and Y ₄ each independently represent a hydrogen atom or a monovalent substituent, Y ₂ , Y ₃ and Y each representing a carboxy group, a substituted or unsubstituted carbamoyl group, or a cyano group. ₄ may be bonded to each other to form a ring, M represents a hydrogen atom or a monovalent counter cation, and n represents 0, 1 or 2. The azo compound or a salt thereof according to claim 13, wherein the azo compound represented by the general formula (1) is an azo compound represented by the following general formula (3).

(In General Formula (3), R ₃ represents a monovalent substituent. X ₁ , X ₂ , X ₃ , X ₄ , and X ₅ each independently represents a hydrogen atom or a monovalent substituent. M represents a hydrogen atom or a monovalent counter cation, and n represents 0, 1 or 2. The azo compound or a salt thereof according to claim 13, wherein the azo compound represented by the general formula (1) is an azo compound represented by the following general formula (4).

(In General Formula (4), R ₃ represents a monovalent substituent. X ₁ , X ₂ , X ₃ , X ₄ , and X ₅ are each independently a hydrogen atom or a monovalent substituent. M represents a hydrogen atom or a monovalent counter cation, and n represents 0, 1 or 2.)