JP5099295B2 - Magenta ink for inkjet recording - Google Patents

Description

  The present invention relates to a magenta ink for inkjet recording.

  A magenta ink is required to form a full-color image using the ink jet recording method. As an example of a general magenta dye used for the ink, relatively good jetting stability and color developability are imparted to the ink. C. which is a monoazoxanthene dye that can be produced. I. Acid Red 14 and C.I., a disazo dye that can impart relatively good jetting stability to ink. I. Direct Red 227 (Patent Document 1) and the like are known.

  By the way, in recent years, as a required characteristic for ink jet recording ink, it is not only necessary to show good jetting stability and color developability, but also a high level of light resistance and resistance to active gases such as ozone have been required. C. I. Acid Red 14 and C.I. I. Direct Red 227 is no exception.

JP 2000-95983 A

  However, the above-mentioned magenta dye C.I. I. Acid Red 14 and C.I. I. Direct Red 227 cannot be said to have sufficient light resistance and ozone resistance, and an inkjet recording image created using magenta ink for inkjet recording containing these dyes cannot be ignored even in a normal storage state. It was a level.

  As described above, among magenta dyes used in general magenta inks for ink jet recording, C.I. I. As in Acid Red 14, those having relatively good color developability, that is, having a hue suitable for obtaining a wide range of blended colors and vivid colors tend to have relatively low light resistance levels and ozone resistance levels. .

  On the other hand, such as 1-alkyl-3-alkyl or aryl-4-cyano-pyrazol-5-ylazo dyes disclosed in British Patent 1,566,985, light resistance and active gas resistance Although magenta dyes are known to be relatively good, they use heavy metal cyanides for their production, which is not only a problem for waste disposal, but also a hue that is insufficient to produce a wide range of blended colors. In addition, there is a problem that a problem easily occurs in contact with various members used in the ink jet recording apparatus. Therefore, an ink jet printer equipped with a magenta ink for ink jet recording using a magenta dye having relatively good light resistance and active gas resistance has a problem in terms of ejection stability during long-term use.

  The present invention is superior in storage stability to magenta ink for ink-jet recording, maintains sufficient jetting stability even during long-term use, has vivid color developability, and has good light resistance to recorded matter using it. It aims at making it possible to give and ozone resistance.

  The inventors have developed a specific pyrazolyl azopyridine (or pyrazolyl azopyrazine) -based dye that is excellent in light resistance and ozone resistance, although it is poor in color developability and jetting stability. By using a specific triazinylamino- (phenylazo) naphthol dye, which has poor color development and jetting stability, although it has poor ozone resistance, as a magenta dye for magenta ink for inkjet recording In addition, the present inventors have found that the good properties of the two are not impaired, and that the respective properties do not become an arithmetic average intermediate level, and that the respective good properties are unexpectedly maintained, and the present invention is achieved. It came to complete.

  That is, the present invention relates to a magenta ink for inkjet recording containing at least a colorant, water and a water-soluble organic solvent, and the colorant is represented by the general formula (1)

(In General Formula (1), R ₁ represents a hydrogen atom, an optionally substituted alkyl group, or an optionally substituted aryl group. R ₂ represents a hydrogen atom, a halogen atom, or a cyano group. R ₃ Represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group or an optionally substituted heterocyclic group, wherein R ₄ , R ₅ , R ₆ and R ₇ are each independently hydrogen An atom, an alkyl group that may be substituted, an aryl group that may be substituted, a heterocyclic group that may be substituted, a sulfonyl group that may be substituted, or an acyl group that may be substituted, provided that R ₄ and R ₅ is not both a hydrogen atom, and R ₆ and R ₇ are not both hydrogen atoms, A ₁ and A ₂ are both carbon atoms that may be substituted, or Even if one of these is substituted Is a have carbon atom, and the other is a nitrogen atom.)
And the form of the free acid represented by the following general formula (2)

(In the general formula (2), R ₈ , R ₉ and R ₁₀ are each independently an alkyl group which may be substituted, an alkoxy group which may be substituted, a halogen atom, a hydrogen atom, a hydroxyl group, or a substituted group. Carbamoyl group which may be substituted, sulfamoyl group which may be substituted, amino group which may be substituted, nitro group, sulfonic acid ester group, alkylsulfonyl group which may be substituted, arylsulfonyl group which may be substituted, carboxyl group Or a carboxylate group, m represents a number of 0, 1 or 2, and R ₁₁ , R ₁₂ and R ₁₃ each independently represents a hydrogen atom, an optionally substituted alkyl group, or a substituted group; A good alkenyl group, an optionally substituted aryl group, an optionally substituted aralkyl group, an optionally substituted alicyclic group or an optionally substituted heterocyclic group Represent.)
And a dye (2) represented by the formula (1):

  The magenta ink for ink jet recording of the present invention comprises a specific pyrazolylazopyridine (or pyrazolylazopyrazine) dye and a specific triazinylamino- (phenylazo) naphthol dye as magenta dyes for magenta ink for ink jet recording. Since they are used in combination, good color developability, jetting stability, light resistance and ozone resistance can be imparted to the resulting ink jet recorded matter.

  In the magenta ink for ink jet recording of the present invention, the dye (1) represented by the above general formula (1) and the free acid form are represented by the general formula (2) as water, a water-soluble organic solvent and a colorant. It contains a dye (2). Below, the characteristic of each dye itself and the effect of those combined use are demonstrated.

  The dye (1) represented by the general formula (1) has excellent light resistance and ozone resistance. However, on the other hand, it has a weak point that it is inferior in color development and vividness. For this reason, when the dye (1) is used alone as the magenta dye of the magenta ink for ink jet recording, it is difficult to secure a sufficient color reproduction range, and it is also difficult to form a high color image. Further, the dye (1) may cause a problem due to contact with some members used in the ink jet recording apparatus. For example, there is a high possibility of attacking metal parts, piezoelectric elements, water-repellent films, and adhesives that adhere them, etc. that constitute an ink jet head. It may cause problems such as foreign matter adhesion. Such aggressiveness against various materials may cause not only a decrease in continuous injection stability but also a decrease in long-term injection stability. Further, when a relatively large amount of the dye (1) is contained in the magenta ink for ink jet recording, there is a concern that the frequency of generating bubbles in the ink flow path leading to the ink jet head and the ink jet head is increased. From this point as well, there is a concern about a decrease in injection stability.

  On the other hand, the dye (2) whose free acid form is represented by the general formula (2), unlike the dye (1), has poor light resistance and ozone resistance, but has excellent sharpness and color development. In addition, the dye (2) is low in aggressiveness to various members used in the ink jet recording apparatus. Rather, some members (for example, rubber members such as rubber caps and wiper rubber) are used for ink jet recording. This function reduces the aggressiveness of magenta ink.

  In general, when two types of dyes having different properties are used in combination, the good properties of the two may be impaired, or even if they are not impaired, each property may be an arithmetic average intermediate level. However, when the dye (1) and the dye (2) are used in combination, there is an unexpected effect that the respective good characteristics are maintained.

  The magenta ink for inkjet recording of the present invention contains the dye (1) and the dye (2) in a weight ratio, preferably 7: 3 to 9: 1, more preferably 8: 2 to 9: 1. To do. By making it within this range, the excellent properties of each dye can be exhibited in a well-balanced manner.

  Further, the total content of the dye (1) and the dye (2) in the magenta ink for inkjet recording is appropriately determined depending on the performance and required characteristics of the ink, but is preferably relative to the total amount of magenta ink for inkjet recording. 1 to 5% by weight, more preferably 2 to 4% by weight. In addition to the dye (1) and the dye (2), other dyes can be used in combination as long as the effects of the present invention are not impaired.

Next, the substituents in the general formulas of the dye (1) and the dye (2) will be described. First, the substituents R _{1 to} R ₇ and A _{1 to} A ₂ in the general formula (1) of the dye (1) will be described.

As described above, R ₁ represents a hydrogen atom, an optionally substituted alkyl group, or an optionally substituted aryl group. R ₂ represents a hydrogen atom, a halogen atom or a cyano group. R ₃ represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group or an optionally substituted heterocyclic group. R ₄ , R ₅ , R ₆ and R ₇ are each independently a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted heterocyclic group, or optionally substituted. Represents a sulfonyl group or an optionally substituted acyl group. However, R ₄ and R ₅ are not both hydrogen atoms, and R ₆ and R ₇ are not both hydrogen atoms. Each of A ₁ and A ₂ is a carbon atom that may be substituted, or one of these is a carbon atom that may be substituted, and the other is a nitrogen atom.

  As a halogen atom in General formula (1), a fluorine atom, a chlorine atom, a bromine atom, etc. are mentioned.

  In the general formula (1), the alkyl group in the alkyl group which may be substituted is preferably an alkyl group having 1 to 6 carbon atoms, and examples of the substituent include a hydroxyl group, an alkoxy group (methoxy group, Ethoxy group, etc.), cyano group, halogen atom (fluorine atom, chlorine atom, bromine atom, etc.), ionic hydrophilic group (carboxylate, sulfonate, etc.). Specific examples of the alkyl group which may be substituted include methyl group, ethyl group, n-butyl group, isopropyl group, tert-butyl group, hydroxyethyl group, methoxyethyl group, cyanoethyl group, trifluoromethyl group, 3- Examples include a sulfopropyl group and a 4-sulfobutyl group.

  In the general formula (1), the aryl group in the optionally substituted aryl group is preferably an aryl group having 6 to 12 carbon atoms excluding the carbon atoms of the substituent. Examples of substituents include alkyl groups (methyl group, ethyl group, isopropyl group, tert-butyl group, n-octyl group, etc.), alkoxy groups (see above), halogen atoms (see above), alkylamino groups (methyl). Amino group, dimethylamino group, etc.), amide group, carbamoyl group, sulfamoyl group, sulfoamide group, hydroxyl group, ester group (methoxycarbonyl group, ethoxycarbonyl group etc.) and ionic hydrophilic group (see above). Specific examples of the aryl group which may be substituted include phenyl group, naphthyl group, p-tolyl group, p-octylphenyl group, mesityl group, p-methoxyphenyl group, o-chlorophenyl group and m- (3-sulfo group. Propylamino) phenyl group and the like.

  In the general formula (1), the heterocyclic group in the optionally substituted heterocyclic group is preferably a 5-membered or 6-membered heterocyclic group. Examples of the substituent include an amide group, a carbamoyl group, a sulfamoyl group, a sulfoamide group, a hydroxyl group, an ester group (see above), and an ionic hydrophilic group (see above). Specific examples of the heterocyclic group which may be substituted include 2-pyridyl group, 2-thienyl group, 2-thiazolyl group, 2-benzothiazolyl group, 2-furyl group, 6-sulfobenzothiazolyl group and 6 -Sulfonate benzothiazolyl group etc.).

  In the general formula (1), examples of the substituent of the sulfonyl group which may be substituted include an alkyl group (see above) and an aryl group (see above). Specific examples of the sulfonyl group which may be substituted include a methylsulfonyl group and a phenylsulfonyl group.

  In the general formula (1), the acyl group of the acyl group which may be substituted is preferably an acyl group having 1 to 12 carbon atoms excluding the carbon atoms of the substituent. Examples of the substituent include an ionic hydrophilic group (see above). Specific examples of the acyl group that may be substituted include an acetyl group, a benzoyl group, and a chloroacetyl group.

In the general formula (1), as described above, A ₁ and A ₂ are both carbon atoms that may be substituted, or carbon atoms that one of these may be substituted. The other is a nitrogen atom. A case in which both A ₁ and A ₂ are carbon atoms is preferable in that a more excellent performance can be exhibited. Examples of the substituent bonded to a carbon atom of A ₁ and A _2, an alkyl group having 1 to 3 carbon atoms, a carboxyl group, a carbamoyl group and cyano group.

In general formula (1), R ₄ and R ₅ are not both hydrogen atoms, and R ₆ and R ₇ are not both hydrogen atoms. Moreover, since there exists a tendency for the water solubility of dye (1) to improve when the number of substitution of a sulfonic acid group or a carboxyl group increases, it is preferable to adjust those substitution numbers as needed.

As a preferred embodiment of the dye (1), in the general formula (1), R ₁ is an alkyl group, R ₂ is a cyano group, R ₃ is a hydrogen atom or an optionally substituted heterocyclic group, R ₄ is a hydrogen atom, An optionally substituted heterocyclic group or a substituted aryl group, R ₅ and R ₆ are substituted heterocyclic groups or a substituted aryl group, R ₇ is a hydrogen atom, and A ₁ is substituted. And an embodiment in which A ₂ is an optionally substituted carbon atom.

As a more preferred embodiment of the dye (1), in the general formula (1), R ₁ is substituted with a tert-butyl group, R ₂ is a cyano group, R ₃ is substituted with a hydrogen atom or a sulfonic acid group or an alkali metal base thereof. Benzothiazolyl group (preferably benzothiazol-2-yl group), benzothiazolyl group (preferably benzothiazol-2-yl group) R ₄ may be substituted with a hydrogen atom, a sulfonic acid group or an alkali metal base thereof, or A trialkylphenyl group (preferably a mesityl group) substituted with a sulfonic acid group or an alkali metal base thereof, and R ₅ and R ₆ are each independently mono- or mono-substituted or optionally substituted with a sulfonic acid group or an alkali metal base thereof A trialkylphenyl group (preferably a p-octylphenyl group or a mesityl group) or Sulfonic acid group or alkali metal base in a benzothiazolyl group substituted (preferably benzothiazol-2-yl group), R ₇ is a hydrogen atom, A ₁ is an alkyl group (preferably methyl group) substituted with In this embodiment, A ₂ is a carbon atom that may be substituted with a cyano group.

Preferable specific examples of the dye (1) include compounds represented by the following chemical formulas (1-A) to (1-E).

The compound represented by the chemical formula (1-A) is represented by the general formula (1), in which R ₁ is a tert-butyl group, R ₂ is a cyano group, R ₃ is a benzothiazol-2-yl group, and R ₄ is a hydrogen atom. , R ₅ and R ₆ are p-octylphenyl groups, R ₇ is a hydrogen atom, A ₁ is a carbon atom substituted with a methyl group, and A ₂ is a carbon atom substituted with a cyano group. is there.

In the compound represented by the chemical formula (1-B), in general formula (1), R ₁ is a tert-butyl group, R ₂ is a cyano group, R ₃ and R ₄ are benzothiazol-2-yl groups, R ₅ And R ₆ is a mesityl group, R ₇ is a hydrogen atom, A ₁ is a carbon atom substituted with a methyl group, and A ₂ is a carbon atom.

The compound represented by the chemical formula (1-C) is represented by the following general formula (1): R ₁ is a tert-butyl group, R ₂ is a cyano group, R ₃ and R ₄ are 6-sulfo sodium salts benzothiazole-2- An yl group, R ₅ and R ₆ are 3-sulfo sodium salt-mesityl groups, R ₇ is a hydrogen atom, A ₁ is a carbon atom substituted with a methyl group, and A ₂ is a carbon atom.

In the compound represented by the chemical formula (1-D), R ₁ is a tert-butyl group, R ₂ is a cyano group, R ₃ and R ₄ are hydrogen atoms, and R ₅ and R ₆ are mesityl in the general formula (1). In this embodiment, R ₇ is a hydrogen atom, A ₁ is a carbon atom substituted with a methyl group, and A ₂ is a carbon atom.

The compound represented by the chemical formula (1-E) is represented by the following general formula (1): R ₁ is a tert-butyl group, R ₂ is a cyano group, R ₃ and R ₄ are 6-sulfo potassium salts benzothiazole-2- An yl group, R ₄ and R ₅ are 3-sulfo potassium salt-mesityl groups, R ₇ is a hydrogen atom, A ₁ is a carbon atom substituted with a methyl group, and A ₂ is a carbon atom.

  The dye (1) represented by the general formula (1) can be produced according to steps (a) to (c) described below.

Step (a)
A diazonium salt is formed by reacting the aminopyrazole represented by the chemical formula (1a) with a diazotizing agent. As the diazotizing agent, a dilute hydrochloric acid aqueous solution of sodium nitrite can be preferably used. Isopentyl nitrite and nitrosyl sulfuric acid can also be used.

The substituents R ₁ and R ₂ in the chemical formula (1a) are as described in the dye (1). The chemical formula (1a) aminopyrazole is a method described in US Pat. No. 3,336,285, Heterocycles, 20,519 (1983), Japanese Patent Publication No. 6-19036, and the like. Can be synthesized.

Step (b)
Next, the diazonium salt formed in the step (a) is reacted with a coupling agent represented by the chemical formula (1b) to form a compound represented by the chemical formula (1c).

The substituents R _{1 to} R ₇ in the chemical formulas (1b) and (1c) are as described for the dye (1). The pyridine coupling agent of the chemical formula (1c) can be synthesized by the method described in JP-A-51-83631, JP-A-49-74718, JP-B-52-46230, etc. .

Step (c)
Next, by reacting the compound formed in step (b) with an alkylating agent, an arylating agent or a heterylating agent in the presence of a base, the dye (1) represented by the general formula (1) is obtained. can get. Examples of the base used in this step include organic bases such as diisopropylethylamine; inorganic bases such as potassium carbonate, sodium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium hydroxide, and potassium hydroxide. The alkylating agent is a compound represented by “RX”. Here, R is an optionally substituted alkyl group. X is a halogen atom or OSO ₂ R ′, and R ′ is an aryl group such as an alkyl group or a phenyl group. The arylating agent is a compound represented by “Ar-X”. Here, Ar is a phenyl group substituted with an electron-withdrawing group (preferably substituted with a substituent having a total Hammett's σp value of 0.2 or more). A heterylating agent is a compound represented by “Het-X”. Here, Het is preferably a heterocycle such as a 2-pyridyl group, 2-thienyl group, 2-thiazolyl group, 2-benzothiazolyl group, triazyl group, 2-furyl group and the like.

Next, the substituents R _{8 to} R ₁₃ in the general formula (2) of the dye (2) will be described. Examples of the substituent that can be bonded to each substituent include those described in the general formula (1) of the dye (1).

As described above, in the general formula (2), R ₈ , R ₉ and R ₁₀ are each independently an alkyl group which may be substituted, an alkoxy group which may be substituted, a halogen atom, a hydrogen atom, or a hydroxyl group. An optionally substituted carbamoyl group, an optionally substituted sulfamoyl group, an optionally substituted amino group, a nitro group, a sulfonate group, an optionally substituted alkylsulfonyl group, an optionally substituted arylsulfonyl Represents a group, a carboxyl group or a carboxylate group. m represents a number of 0, 1 or 2, and R ₁₁ , R ₁₂ and R ₁₃ are each independently a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkenyl group or an optionally substituted group. An aryl group, an aralkyl group which may be substituted, an alicyclic group which may be substituted or a heterocyclic group which may be substituted is represented.

Of the substituents represented by R ₈ , R ₉ and R ₁₀ in the general formula (2), the alkyl group which may be substituted preferably includes an alkyl group having 1 to 9 carbon atoms in total. Specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a trifluoromethyl group, and a dimethylaminomethyl group. The alkoxy group which may be substituted preferably includes an alkoxy group having 1 to 9 carbon atoms. Specific examples thereof include a methoxy group, an isopropoxy group and an n-butoxy group. Specific examples of the halogen atom include a fluorine atom, a chlorine atom and a bromine atom. Specific examples of the carbamoyl group that may be substituted include a carbamoyl group, an N, N-dimethylcarbamoyl group, and a phenylcarbamoyl group. Specific examples of the sulfamoyl group that may be substituted include sulfamoyl group, N-methylsulfamoyl group, N-ethylsulfamoyl group, N-ethyl-N-phenylsulfamoyl group, N, N-dimethylsulfuryl group. Examples include a famoyl group and a p-carboxyphenylsulfamoyl group. Specific examples of the amino group that may be substituted include an N-methylamino group, a carbamoylamino group, an N, N-diethylamino group, and an acetylamino group. Examples of the sulfonate group include a phenoxysulfonyl group. The alkylsulfonyl group which may be substituted is preferably an alkylsulfonyl group having 1 to 9 carbon atoms in total. Specific examples thereof include a hydroxyethylsulfonyl group. The arylsulfonyl group which may be substituted preferably includes an arylsulfonyl group having 6 to 15 carbon atoms in total. Specific examples thereof include a benzylsulfonyl group. Specific examples of the carboxylic acid ester group include a methoxycarboquinyl group.

Of the substituents represented by R ₁₁ , R ₁₂ and R ₁₃ in the general formula (2), the alkyl group which may be substituted preferably includes an alkyl group having 1 to 18 carbon atoms in total. Specific examples thereof include an ethyl group, n-butyl group, n-octyl group, ethylhexyl group, hydroxyethyl group, carboxypropyl group, carboxycyclohexylmethyl group, 1-carboxy-2-mercaptoethyl group, 1-carboxy-2. -Carbamoyl-ethyl group, 1-isopropyl-1-carboxymethyl group, 1,2-dicarboxypropyl group, etc. are mentioned. The alkenyl group which may be substituted is preferably an alkenyl group having 2 to 18 carbon atoms in total. Specific examples thereof include 2-methyl-1-propenyl group, vinyl group and allyl group. Specific examples of the aryl group that may be substituted include 3,4-dicarboxyphenyl group, 4-butylphenyl group, 4-carboxyphenyl group, and the like. Specific examples of the aralkyl group which may be substituted include a benzyl group, a 1-carboxy-2-phenyl-ethyl group, a 1-carboxy-2-hydroxyphenylethyl group, and a 4-carboxybenzyl group. Specific examples of the alicyclic group which may be substituted include a cyclohexyl group and a 4-carboxycyclohexyl group. Specific examples of the heterocyclic group which may be substituted include pyridyl group, thiadiazolyl group, benzothiazolyl group, 2,2,6,6-tetramethylpiperidinyl group and the like. In addition, an alkyl group, an alkenyl group, an aryl group, an alicyclic group, an aralkyl group, a heterocyclic group, or the like in which at least one of R ₁₁ , R ₁₂ and R ₁₃ is substituted with 1 to 4 carboxyl groups or sulfamoyl groups Can be mentioned. Further, R ₁₁ and R ₁₂ may each independently be a hydrogen atom or a trisubstituted phenyl group. Here, the three substituents of the 3-substituted phenyl group are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an optionally substituted alkyl group having 1 to 9 carbon atoms, or 1 to 9 carbon atoms in total. It represents an optionally substituted alkoxy group, an optionally substituted carbamoyl group, an optionally substituted sulfamoyl group, an optionally substituted amino group, a nitro group, a sulfonate group or a carboxylate group.

As a preferred embodiment of the dye (2), an alkyl group, an alkenyl group, an aryl in which at least one of R ₁₁ , R ₁₂ or R ₁₃ is substituted with 1 to 4 carboxyl groups or sulfamoyl groups in the general formula (2) Group, aralkyl group or cyclohexyl group.

  Further, the dye (2) represented by the general formula (2) has a total of 6 or less, preferably 5 or less, in particular, a sulfonic acid group and a carboxyl group or a salt group of these acids in the structure. Those having 4 or less are preferred. The dye (2) may be used as it is in the free acid form, but may be used as it is when it is obtained in a salt form at the time of production, or may be converted into a desired salt form. Some of the acid groups may be of a salt type, and a salt type dye and a free acid type dye may be mixed. Examples of such salt types include salts of alkali metals such as Na, Li, and K, ammonium salts optionally substituted with alkyl groups or hydroxyalkyl groups, and organic amine salts. Examples of organic amines include lower alkyl amines, hydroxy-substituted lower alkyl amines, carboxy-substituted lower alkyl amines, and polyamines having 2 to 10 alkyleneimine units having 2 to 4 carbon atoms. In the case of these salt types, the type is not limited to one type, and a plurality of types may be mixed.

As a preferred embodiment of the dye (2), in the general formula (2), m is 0, R ₈ is a carboxyl group, a carbamoyl group, a trifluoromethyl group or a sulfamoyl group, and R ₉ and R ₁₀ are hydrogen atoms. And R ₁₁ is a phenyl group or a carboxyalkyl group which may be substituted with a carboxyl group or a sulfamoyl group, R ₁₂ is a hydrogen atom, and R ₁₃ is a hydrogen atom or an alkyl group.

  Particularly preferred specific examples of the dye (2) include compounds represented by the following chemical formulas (2-A) to (2-E).

In the compound represented by the chemical formula (2-A), in general formula (2), m is 0, and R ₈ is a carboxyl group located at the 2-position of the phenyl group bonded to the azo group, R ₉ , R ₁₀ And R ₁₂ is a hydrogen atom, R ₁₁ is a 2-carboxyphenyl group, and R ₁₃ is a hydrogen atom.

In the compound represented by the chemical formula (2-B), in the general formula (2), m is 0, and R ₈ is a carbamoyl group located at the 2-position of the phenyl group bonded to the azo group, R ₉ , R ₁₀ And R ₁₂ is a hydrogen atom, R ₁₁ is a 2-carboxyphenyl group, and R ₁₃ is a hydrogen atom.

In the compound represented by the chemical formula (2-C), in general formula (2), m is 0, and R ₈ is a sulfamoyl group located at the 3-position of the phenyl group bonded to the azo group, R ₉ , R ₁₀ And R ₁₂ is a hydrogen atom, R ₁₁ is a 2-sulfamoylphenyl group, and R ₁₃ is an isopropyl group.

In the general formula (2), the compound represented by the chemical formula (2-D) is a trifluoromethyl group in which m is 0 and R ₈ is located at the 2-position of the phenyl group bonded to the azo group, R ₉ , In this embodiment, R ₁₀ and R ₁₂ are hydrogen atoms, R ₁₁ is a 1-carboxy-2-methylbutyl group, and R ₁₃ is a methyl group.

In the compound represented by the chemical formula (2-E), in general formula (2), m is 0, and R ₈ is a carboxyl group located at the 2-position of the phenyl group bonded to the azo group, R ₉ , R ₁₀ And R ₁₂ is a hydrogen atom, R ₁₁ is a phenyl group, and R ₁₃ is a hydrogen atom.

  The dye (2) represented by the general formula (2) can be produced according to a known method. For example, it can be produced according to the following steps (A) to (C).

Step (A)
First, 2-aminobenzoic acid (anthranilic acid) and 1-amino-8-hydroxy-3,6-naphthalenedisulfonic acid (H acid) are used in conventional methods (for example, “New dye chemistry” by Yutaka Hosoda (Showa 48). (December 21, published by Gihodo) See pages 396-409) to produce a monoazo compound through diazotization and coupling reactions.

Process (B)
The obtained monoazo compound is added to the cyanuric chloride suspension and reacted for several hours. At this time, the pH of the reaction solution is maintained at 4-6 and the temperature at 0-5 ° C. Following this reaction, a 2-aminobenzoic acid (anthranilic acid) aqueous solution is added to the reaction solution so that the liquid does not become alkaline at room temperature, and a condensation reaction is performed for several hours. Subsequently, a hydrolysis reaction is performed by adding a 25% aqueous sodium hydroxide solution at a reaction solution temperature of 50 to 60 ° C. to make it strongly alkaline, thereby completing the reaction.

Process (C)
After completion of the reaction, the reaction solution is cooled and salted out with sodium chloride to obtain the dye (2).

  Next, water and a water-soluble organic solvent constituting the magenta ink for inkjet recording of the present invention will be described.

  As the water used in the present invention, ion-exchanged water with less salts is preferable. Since the content of water in the magenta ink for ink jet recording is positioned as the balance of other components, it depends on the content of other components, but is usually 10 to 90% by weight, preferably 40 to 80% by weight. It is.

  The water-soluble organic solvent used in the present invention mainly includes a wetting agent for preventing the ink from drying at the nozzle tip of the inkjet head and a penetrating agent for mainly increasing the drying speed on the paper surface. .

  Examples of the wetting agent for preventing ink drying include lower alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, and tert-butyl alcohol; dimethylformamide, Amides such as dimethylacetamide; Ketones or ketoalcohols such as acetone and diacetone alcohol; Ethers such as tetrahydrofuran and dioxane; Polyalkylene glycols such as polyethylene glycol and polypropylene glycol; Ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, and triethylene glycol , Dipropylene glycol, tripropylene glycol, thiodiglycol, hexylene glycol, etc. Glycol; glycerin; 2-pyrrolidone; N- methyl-2-pyrrolidone; 1,3-dimethyl-2-imidazolidinone. Among these, polyhydric alcohols such as alkylene glycol and glycerin are preferable.

  The blending amount of the wetting agent for preventing the ink from drying in the magenta ink for ink jet recording is generally 0 to 95% by weight, preferably 10 to 80% by weight, and more preferably 10 to 50% by weight.

  On the other hand, as a penetrant for increasing the drying speed on paper, for example, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol propyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol propyl ether, triethylene glycol Methyl ether, triethylene glycol ethyl ether, triethylene glycol propyl ether, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol propyl ether, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol propyl ether, tripropylene Glycol methyl ether, trip Propylene glycol ethyl ether, glycol ethers such as tripropylene glycol propyl ether.

In the magenta ink for ink jet recording, the blending amount of the penetrant for increasing the drying speed is generally 0 to 20% by weight, preferably 0.1 to 15% by weight, more preferably 1 to 10% by weight. . It should be noted that if the blending amount is excessive, the permeability of the ink to the paper becomes too high, which may cause bleeding.

  The magenta ink for ink-jet recording of the present invention further contains conventionally known additives such as viscosity modifiers such as polyvinyl alcohol, cellulose and water-soluble resins; surface tension modifiers; Also good.

  The magenta ink for ink-jet recording of the present invention comprises a colorant containing the above-mentioned dye (1) and dye (2), water, a water-soluble organic solvent, and various other additives as required. Can be prepared by mixing uniformly.

Examples 1-7 and Comparative Examples 1-6
A magenta ink for inkjet recording was prepared by uniformly mixing the ink composition components shown in Table 1. Here, dyes (1-A) to (1-E) are compounds represented by chemical formulas (1-A) to (1-E), respectively, and dyes (2-A) to (2-E) are respectively It corresponds to the compounds represented by the chemical formulas (2-A) to (2-E).

  For the obtained magenta ink for ink-jet recording, (a) jetting stability evaluation, (b) color development evaluation, (c) ozone resistance evaluation, (d) light resistance evaluation and (e) comprehensive evaluation are as follows. went.

  First, a desired ink cartridge was filled with magenta ink for ink jet recording, and the ink cartridge was mounted on a digital multi-function peripheral equipped with an ink jet printer (manufactured by Brother Industries, Ltd .; DCP-110C) to evaluate printing. Samples for (b) color development evaluation, (c) ozone resistance evaluation, and (d) light resistance evaluation include glossy paper (manufactured by Brother Industries, Ltd .; photographic glossy paper (model number: BP60GLA)) and magenta ink. A gradation sample was printed and a patch with an initial OD value of 1.0 was used.

(A) Evaluation of ejection stability Continuous printing evaluation of 100 million dots (about 30,000 sheets) was performed, and evaluation was performed according to the following criteria. The obtained results are shown in Table 1.
Judgment criteria for jetting stability ◎ ... No ejection or ejection bending at all during continuous printing ○: There is slight ejection failure or ejection bending during continuous printing, and both ejection or ejection bending is recovered by purging within 5 times ×… There are many non-ejections and ejection bends during continuous printing. Both non-ejection and ejection bends do not recover in a short time.

(B) Color development evaluation The above-described gradation sample was evaluated based on the following evaluation criteria as to whether or not the magenta color was sufficiently expressed by visual observation. The obtained results are shown in Table 1.
Evaluation criteria for color development ○: Magenta color is sufficiently expressed ×: Magenta color expression is insufficient

(C) Ozone resistance evaluation An ozone resistance test was performed using the gradation sample described above. The ozone resistance test was performed using an ozone weather meter OMS-H manufactured by Suga Test Instruments Co., Ltd., and left for 40 hours at an ozone concentration of 1 ppm, a bath temperature of 24 ° C., and a humidity of 60% RH. For the magenta color patch showing an OD value of 1.0 before the test, the OD value before and after the ozone resistance test was measured. The OD value was measured by Spectrolino (light source: D ₆₅ ; field of view: 2 °; Status A) manufactured by Gretag Macbeth. From the following formula I, the patch having an OD value of 1.0 before the test was determined as the ozone resistance OD value reduction rate. The obtained ozone resistance OD value reduction rate was evaluated based on the following evaluation criteria. The obtained results are shown in Table 1.

Ozone resistance evaluation criteria ◎… Ozone resistance OD value decrease rate is less than 20% ○… Ozone resistance OD value decrease rate is 20% or more and less than 30% △… Ozone resistance OD value decrease rate is 30% or more and less than 40% ×: Ozone-resistant OD value reduction rate is 40% or more

(D) Light resistance evaluation The light resistance test was done using the gradation sample mentioned above. The light resistance test was performed using a strong energy xenon weather meter SC750-WN manufactured by Suga Test Instruments Co., Ltd. Xenon lamp light was used as a light source, and irradiation was performed at room temperature of 25 ° C., humidity of 50% RH, and illuminance of 93000 Lux for 100 hours. About the magenta color patch which shows OD value 1.0 before a test, the OD value after a light resistance test was measured. The OD value was measured by Spectrolino (light source: D ₆₅ ; field of view: 2 °; Status A) manufactured by Gretag Macbeth. From the following formula II, the light resistance OD value reduction rate was determined for a patch having an OD value of 1.0 before the test. The obtained light resistance OD value reduction rate was evaluated based on the following evaluation criteria. The obtained results are shown in Table 1.

Light resistance evaluation criteria ◎… Light resistance OD value decrease rate is less than 20% ○… Light resistance OD value decrease rate is 20% or more and less than 30% △… Light resistance OD value decrease rate is 30% or more and less than 40% ×… Light resistance OD value reduction rate is 40% or more

(E) Comprehensive evaluation For each ink, comprehensive evaluation was performed according to the following evaluation criteria from the above results. The obtained results are shown in Table 1.
Overall evaluation criteria G: All evaluation results are ◎ or ○ NG: Some of the evaluation results have Δ or ×

  From the results in Table 1, the knowledge obtained for each of the examples and comparative examples is as follows.

  Example 1 (Total dye content 3%): The ink contains 5% of the dye (2-E), which can be used without any problem for the member and has good color development, with respect to the whole dye. Can be stably ejected, and color development was also good. Since 95% of the dye (1-B) having good ozone resistance and light resistance was contained in the whole dye, the ozone resistance and light resistance were good.

  Example 2 (Total dye content 3%): The ink contains 10% of the dye (2-A) that can be used without any problem with respect to the member and has good color development. Can be stably ejected, and color development was also good. Since 90% of the dye (1-A) having good ozone resistance and light resistance was contained with respect to the whole dye, the ozone resistance and light resistance were good.

  Example 3 (Total Dye Content 3%): The ink contains 20% of the dye (2-B), which can be used without any problem with respect to the member, and has good color development. Can be stably ejected, and color development was also good. Since 80% of the dye (1-B) having good ozone resistance and light resistance was contained with respect to the whole dye, the ozone resistance and light resistance were good.

  Example 4 (total dye content 3%): 30% of the dye (2-C), which can be used without any problem for the member and has good color development, is contained in the total amount of the ink. Can be stably ejected, and color development was also good. Since 70% of the dye (1-C) having good ozone resistance and light resistance was contained with respect to the whole dye, the ozone resistance and light resistance were good.

  Example 5 (Total dye content 3%): The ink contains 40% of the dye (2-A), which can be used without any problem for the member and has good color development, with respect to the entire dye. Can be stably ejected, and color development was also good. Since the dye (1-B) having good ozone resistance and light resistance is 60% of the whole dye, the ozone resistance and light resistance were good, but the inclusion of the dye (1-B) Since the ratio was somewhat small, ozone resistance and light resistance were somewhat worse than those of Examples 1-4, 6 and 7.

  Example 6 (total dye content 2%): The ink contains 20% of the dye (2-D), which can be used without any problem for the member and has good color development, with respect to the whole dye. Can be stably ejected, and color development was also good. Since 80% of the dye (1-D) having good ozone resistance and light resistance was contained with respect to the whole dye, the ozone resistance and light resistance were good.

  Example 7 (total dye content: 4%): Since the dye (2-E), which can be used without any problem for the member and has good color development, is contained in an amount of 20%, the ink Can be stably ejected, and color development was also good. Since 80% of the dye (1-E) having good ozone resistance and light resistance was contained with respect to the whole dye, the ozone resistance and light resistance were good.

  Comparative Example 1 (Total Dye Content 3%): Since the dye used was only the dye (1-A), ozone resistance and light resistance were good, but there was a problem in jetting stability. In addition, color development was insufficient.

  Comparative Example 2 (Total dye content 3%): C.I. I. Since 20% of Acid Red 14 was contained with respect to the whole dye, the ink could be stably ejected and the color development was good. However, C.I. I. Since Acid Red 14 has poor ozone resistance and light resistance, ozone resistance and light resistance were insufficient even when mixed with the dye (1-C).

  Comparative Example 3 (Total Dye Content 3%): C. which can be used without problems for members. I. Since the direct red 227 is contained in an amount of 20% with respect to the entire dye, the ink could be stably ejected. However, C.I. I. Since Direct Red 227 was contained in an amount of 20% based on the whole dye, color development was insufficient. In addition, C.I. I. Since Direct Red 227 has poor ozone resistance and light resistance, ozone resistance and light resistance were insufficient even when mixed with dye (1-D).

  Comparative Example 4 (Total dye content 3%): Since the dye used was only the dye (2-A), the ink could be stably ejected and the color development was also good. However, since the dye (2-A) has poor ozone resistance and light resistance, the ozone resistance and light resistance were insufficient.

  Comparative Example 5 (Total dye content 3%): The dye used was C.I. I. Since only Acid Red 14 was used, ink could be stably ejected and color development was also good. However, C.I. I. Since Acid Red 14 had poor ozone resistance and light resistance, ozone resistance and light resistance were insufficient.

  Comparative Example 6 (Total dye content 3%): The dye used was C.I. I. Since only Direct Red 227 was used, ink could be ejected stably. However, C.I. I. Since Direct Red 227 has poor color development, ozone resistance and light resistance, color development, ozone resistance and light resistance were insufficient.

According to the present invention, with respect to magenta ink for ink jet recording, it has excellent storage stability, maintains sufficient jetting stability even in long-term use, has vivid color developability, and is good for recorded matter using it. Light resistance and ozone resistance can be imparted.

Claims (17)

In a magenta ink for inkjet recording containing at least a colorant, water, and a water-soluble organic solvent, the colorant is represented by the general formula (1)

(In General Formula (1), R ₁ represents a hydrogen atom, an optionally substituted alkyl group, or an optionally substituted aryl group. R ₂ represents a hydrogen atom, a halogen atom, or a cyano group. R ₃ Represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group or an optionally substituted heterocyclic group, wherein R ₄ , R ₅ , R ₆ and R ₇ are each independently hydrogen An atom, an alkyl group that may be substituted, an aryl group that may be substituted, a heterocyclic group that may be substituted, a sulfonyl group that may be substituted, or an acyl group that may be substituted, provided that R ₄ and R ₅ is not both a hydrogen atom, and R ₆ and R ₇ are not both hydrogen atoms, A ₁ and A ₂ are both carbon atoms that may be substituted, or Even if one of these is substituted Is a have carbon atom, and the other is a nitrogen atom.)
And the form of the free acid represented by the following general formula (2)

(In the general formula (2), R ₈ , R ₉ and R ₁₀ are each independently an alkyl group which may be substituted, an alkoxy group which may be substituted, a halogen atom, a hydrogen atom, a hydroxyl group, or a substituted group. Carbamoyl group which may be substituted, sulfamoyl group which may be substituted, amino group which may be substituted, nitro group, sulfonic acid ester group, alkylsulfonyl group which may be substituted, arylsulfonyl group which may be substituted, carboxyl group Or a carboxylate group, m represents a number of 0, 1 or 2, and R ₁₁ , R ₁₂ and R ₁₃ each independently represents a hydrogen atom, an optionally substituted alkyl group, or a substituted group; A good alkenyl group, an optionally substituted aryl group, an optionally substituted aralkyl group, an optionally substituted alicyclic group or an optionally substituted heterocyclic group Represent.)
The dye (2) represented by the formula (1) is contained in a weight ratio of 7: 3 to 9: 1 and 1 to 5% by weight in total with respect to the total amount of magenta ink for inkjet recording. A magenta ink for ink jet recording. In the general formula (1), R ₁ is an alkyl group, R ₂ is a cyano group, R ₃ is a hydrogen atom or an optionally substituted heterocyclic group, R ₄ is a hydrogen atom, an optionally substituted heterocyclic group or a substituted group An aryl group, R ₅ and R ₆ are substituted heterocyclic groups or substituted aryl groups, R ₇ is a hydrogen atom, A ₁ is a substituted carbon atom, ₂ is a carbon atoms which may be substituted claim 1 Symbol placement jet recording magenta ink. In the general formula (1), R ₁ is a tert-butyl group, R ₃ is a hydrogen atom or a benzothiazolyl group which may be substituted with a sulfonic acid group or an alkali metal base thereof, R ₄ is a hydrogen atom or a sulfonic acid A benzothiazolyl group which may be substituted with a group or an alkali metal base thereof, or a sulfonic acid group or a trialkylphenyl group which is substituted with an alkali metal base thereof, and R ₅ and R ₆ are each independently a sulfonic acid group or a group thereof A mono- or trialkylphenyl group which may be substituted with an alkali metal base or a sulfonic acid group or a benzothiazolyl group substituted with the alkali metal base, and A ₁ is a carbon atom substituted with an alkyl group; Inkuji of ₂ claim 2, wherein the carbon atoms which may be substituted with a cyano group Magenta ink for jet recording. In the general formula (1), R ₃ is a hydrogen atom or a benzothiazol-2-yl group which may be substituted with a sulfonic acid group or an alkali metal base thereof, and R ₄ is a hydrogen atom, a sulfonic acid group or an alkali metal thereof. A benzothiazol-2-yl group optionally substituted with a base or a sulfonic acid group or a trimethylphenyl group substituted with an alkali metal base thereof, and R ₅ and R ₆ are each independently a sulfonic acid group or an alkali thereof A p-octylphenyl group or mesityl group which may be substituted with a metal base, or a benzothiazol-2-yl group substituted with a sulfonic acid group or an alkali metal base thereof, and A ₁ is substituted with a methyl group is a carbon atom, Inkuji of claim 3 wherein a ₂ is a carbon atoms which may be substituted with a cyano group Tsu door recording magenta ink. In the general formula (1), R ₃ is a benzothiazol-2-yl group, R ₄ is a hydrogen atom, R ₅ and R ₆ are p-octylphenyl groups, and A ₂ is substituted with a cyano group. The magenta ink for ink-jet recording according to claim 4 , wherein the magenta ink is a carbon atom. The magenta for ink jet recording according to claim 4 , wherein, in the general formula (1), R ₃ and R ₄ are benzothiazol-2-yl groups, R ₅ and R ₆ are mesityl groups, and A ₂ is a carbon atom. ink. In the general formula (1), R ₃ and R ₄ are 6-sulfo sodium salt benzothiazol-2-yl groups, R ₅ and R ₆ are 3-sulfo sodium salt mesityl groups, and A ₂ is a carbon atom. The magenta ink for ink jet recording according to claim 4 . The magenta ink for ink jet recording according to claim 4 , wherein, in the general formula (1), R ₃ and R ₄ are hydrogen atoms, R ₅ and R ₆ are mesityl groups, and A ₂ is a carbon atom. In the general formula (1), R ₃ and R ₄ are 6-sulfo potassium salt benzothiazol-2-yl groups, R ₅ and R ₆ are 3-sulfo potassium salt-mesityl groups, and A ₂ is a carbon atom. The magenta ink for inkjet recording according to claim 4 . In the general formula (2), m is 0, R ₈ is a carboxyl group, a carbamoyl group, a trifluoromethyl group, or a sulfamoyl group, R ₉ and R ₁₀ are hydrogen atoms, and R ₁₁ is a carboxyl group or a sulfamoyl group. The magenta ink for ink-jet recording according to claim 1, which is a phenyl group or a carboxyalkyl group which may be substituted with a group, R ₁₂ is a hydrogen atom, and R ₁₃ is a hydrogen atom or an alkyl group. In the general formula (2), a carboxyl group located at the 2-position of the phenyl group R ₈ is bonded to the azo group, R ₁₁ is 2-carboxyphenyl group, according to claim 9 wherein R ₁₃ is a hydrogen atom Magenta ink for inkjet recording. In the general formula (2), a carbamoyl group located at the 2-position of the phenyl group R ₈ is bonded to the azo group, R ₁₁ is 2-carboxyphenyl group, according to claim 9 wherein R ₁₃ is a hydrogen atom Magenta ink for inkjet recording. In the general formula (2), R ₈ is a sulfamoyl group located at the 3-position of a phenyl group bonded to an azo group, R ₁₁ is a 2-sulfamoylphenyl group, and R ₁₃ is an isopropyl group. The magenta ink for inkjet recording according to 9 . In the general formula (2), R ₈ is a trifluoromethyl group located at the 2-position of the phenyl group bonded to the azo group, R ₁₁ is a 1-carboxy-2-methylbutyl group, and R ₁₃ is a methyl group. The magenta ink for ink jet recording according to claim 9 . 10. The ink jet recording according to claim 9 , wherein, in the general formula (2), R ₈ is a carboxyl group located at the 2-position of the phenyl group bonded to the azo group, R ₁₁ is a phenyl group, and R ₁₃ is a hydrogen atom. For magenta ink. In a magenta ink for inkjet recording containing at least a colorant, water, and a water-soluble organic solvent, the colorant is represented by the general formula (1)

(In the general formula (1), R ₁ Is a tert-butyl group and R ₂ Is a cyano group and R ₃ And R ₄ Is a hydrogen atom and R ₅ And R ₆ Is a mesityl group and R ₇ Is a hydrogen atom and A ₁ Is a nitrogen atom and A ₂ Is a carbon atom. )
And the form of the free acid represented by the following general formula (2)

(In the general formula (2), R ₈ , R ₉ And R ₁₀ Each independently represents an alkyl group that may be substituted, an alkoxy group that may be substituted, a halogen atom, a hydrogen atom, a hydroxyl group, a carbamoyl group that may be substituted, a sulfamoyl group that may be substituted, It may represent an amino group, a nitro group, a sulfonic acid ester group, an optionally substituted alkylsulfonyl group, an optionally substituted arylsulfonyl group, a carboxyl group or a carboxylic acid ester group. m represents a number of 0, 1 or 2, and R ₁₁ , R ₁₂ And R ₁₃ Are each independently a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkenyl group, an optionally substituted aryl group, an optionally substituted aralkyl group, an optionally substituted alicyclic group or The heterocyclic group which may be substituted is represented. )
A magenta ink for ink-jet recording, comprising a dye (2) represented by the formula:
  In a magenta ink for inkjet recording containing at least a colorant, water, and a water-soluble organic solvent, the colorant is represented by the general formula (1)

(In the general formula (1), R ₁ Is a tert-butyl group and R ₂ Is a cyano group and R ₃ And R ₄ Is a 6-sulfo potassium salt benzothiazol-2-yl group, R ₅ And R ₆ Is a 3-sulfo potassium salt-mesityl group, R ₇ Is a hydrogen atom and A ₁ Is a nitrogen atom and A ₂ Is a carbon atom. )
And the form of the free acid represented by the following general formula (2)

(In the general formula (2), R ₈ , R ₉ And R ₁₀ Each independently represents an alkyl group that may be substituted, an alkoxy group that may be substituted, a halogen atom, a hydrogen atom, a hydroxyl group, a carbamoyl group that may be substituted, a sulfamoyl group that may be substituted, It may represent an amino group, a nitro group, a sulfonic acid ester group, an optionally substituted alkylsulfonyl group, an optionally substituted arylsulfonyl group, a carboxyl group or a carboxylic acid ester group. m represents a number of 0, 1 or 2, and R ₁₁ , R ₁₂ And R ₁₃ Are each independently a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkenyl group, an optionally substituted aryl group, an optionally substituted aralkyl group, an optionally substituted alicyclic group or The heterocyclic group which may be substituted is represented. )
A magenta ink for ink-jet recording, comprising a dye (2) represented by the formula: