JP2015124323A - Aqueous ink composition, inkjet recording method and colored matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous ink composition which can improve color developability.SOLUTION: An aqueous ink composition comprises at least a dye represented by formula (1) or salt thereof, and 1,2-alkane diol (R, R, R-Rindependently represent H, a carboxy group, a sulfo group, a nitro group, an alkoxy group which may comprise a substituent or the like; Rand Rindependently represent H, a sulfo group, an alkoxy group which may comprise a substituent, an alkyl group or the like; and n is 0 or 1).

Description

  The present invention relates to an aqueous black ink composition, an ink jet recording method using the same, and a colored body.

  Among various color recording methods, the ink jet recording method, which is one of the representative methods, generates small ink droplets and attaches them to various recording materials (paper, film, fabric, etc.). Recording method. This method has been spreading rapidly in recent years due to the fact that the recording head is not in direct contact with the recording material and is quiet with little noise generation, and is easy to downsize and speed up. Expected.

  Due to the recent development of ink jet technology, the recording speed in ink jet recording (printing) has been remarkably improved, and ink jet recording for the purpose of commercial printing and printing of documents in offices has been proposed. In this case, the recording material is generally plain paper that does not have an ink receiving layer, and compared with an inkjet-dedicated paper having an ink receiving layer, low color developability at the time of recording becomes a problem. In the black ink used for both, improvement in color developability is strongly desired.

  As a method for obtaining a recorded material with high color development, for example, a method for recording on a recording material by ejecting a larger amount of ink than usual has been proposed. However, when recording is performed by such a method, the dried ink is insufficiently dried, and when the housing of the ink jet printer or the recording surface of the recording material overlaps with another recording material, the other recording material is recorded. Ink adheres to the material and causes stains. Further, when a large amount of ink adheres to the recording material, a wavy phenomenon of the recording material called cockling occurs, which causes a significant deterioration in recording quality. For this reason, there is a strong demand for the development of black ink with high color developability even with a normal ink discharge amount.

  In response to the above-mentioned demands, development of highly colored dyes has been carried out. However, the development of dyes with high color development is technically difficult and there are still few that have sufficient performance. For this reason, generally, a black ink is prepared by mixing a plurality of pigments. However, when an ink is prepared by mixing a plurality of pigments, the hue differs depending on the recording material compared to the case where the ink is prepared with a single pigment; Cheap.

  For example, Patent Document 1 has been proposed as a black ink in which a dye for color adjustment is further blended with a black dye, but it does not sufficiently satisfy market demands.

  Moreover, the dye represented by following formula (1) described in this specification is described in patent documents 2-5.

Japanese Patent No. 3178200 International Publication No. 2006/051850 International Publication No. 2013/035560 JP 2008-69331 A JP 2013-32469 A

  An object of the present invention is to provide a water-based ink composition that can improve color developability.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that an aqueous ink composition containing at least a specific dye represented by the following formula (1) and 1,2-alkanediol. Thus, the inventors have found that the above problems can be solved and completed the present invention.

（上記式（１）中、
Ｒ_１、Ｒ_２、Ｒ_５、Ｒ_６及びＲ_７は、それぞれ独立して水素原子、ハロゲン原子、シアノ基、ヒドロキシ基、カルボキシ基、スルホ基、スルファモイル基、ニトロ基、置換基を有してもよいアルコキシ基、置換基を有してもよいアルキルスルホニル基、アルキル基、置換基を有してもよいアリールスルファモイルアミノ基、及びアルキルカルボニルアミノ基よりなる群から選択される基を表す。
Ｒ_３及びＲ_４は、それぞれ独立して水素原子、ハロゲン原子、シアノ基、スルホ基、カルボキシ基、ニトロ基、置換基を有してもよいアルコキシ基、及びアルキル基よりなる群から選択される基を表す。
ｎは０又は１を表す。）
２）
上記１，２‐アルカンジオールの含有量が、水性インク組成物の総質量に対して１質量％〜２０質量％である上記１）に記載の水性インク組成物。
３）
上記１，２‐アルカンジオールの含有量が、水性インク組成物の総質量に対して５質量％〜２０質量％である上記1）に記載の水性インク組成物。
４）
上記式（１）中、Ｒ_１がカルボキシ基又はスルホ基であり、Ｒ_２が水素原子であり、Ｒ_６がニトロ基、カルボキシ基、又はスルホ基であり、ｎが１である上記１）に記載の水性インク組成物。
５）
上記式（１）中、Ｒ_１及びＲ_３がスルホ基であり、Ｒ_４が水素原子、Ｒ_５が水素原子、カルボキシ基、又はスルホ基であり、Ｒ_６がニトロ基、カルボキシ基、又はスルホ基であり、Ｒ_７が水素原子であり、ｎが１である上記１）に記載の水性インク組成物。
６）
上記１，２−アルカンジオールが、Ｃ３−Ｃ１６アルカンの１，２−ジオールである上記１）〜３）のいずれか一項に記載の水性インク組成物。
７）
上記１，２−アルカンジオールが、Ｃ３−Ｃ８アルカンの１，２−ジオールである上記１）〜３）、又は上記６）のいずれか一項に記載の水性インク組成物。
８）
上記１，２‐アルカンジオールが、１，２−ヘキサンジオール及び１，２−オクタンジオールよりなる群から選択される、少なくとも１種類の１，２−アルカンジオールである上記1）〜３）、又は上記６）〜７）のいずれか一項に記載の水性インク組成物。
９）
上記１）〜８）のいずれか一項に記載の水性インク組成物の液滴を、記録信号に応じて吐出させて、被記録材に付着させることにより記録を行うインクジェット記録方法。
１０）
被記録材が情報伝達用シートである上記９）に記載のインクジェット記録方法。
１１）
上記１）〜８）のいずれか一項に記載の水性インク組成物により着色された着色体。
１２）
上記１）〜８）のいずれか一項に記載の水性インク組成物を含有する容器が装填されたインクジェットプリンタ。 That is, the present invention relates to the following 1) to 12).
1)
A water-based ink composition containing at least a dye represented by the following formula (1) or a salt thereof and 1,2-alkanediol.

(In the above formula (1),
R ₁ , R ₂ , R ₅ , R ₆ and R ₇ each independently have a hydrogen atom, a halogen atom, a cyano group, a hydroxy group, a carboxy group, a sulfo group, a sulfamoyl group, a nitro group, or a substituent. Represents a group selected from the group consisting of an alkoxy group which may have a substituent, an alkylsulfonyl group which may have a substituent, an alkyl group, an arylsulfamoylamino group which may have a substituent, and an alkylcarbonylamino group .
R ₃ and R ₄ are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a cyano group, a sulfo group, a carboxy group, a nitro group, an optionally substituted alkoxy group, and an alkyl group. Represents a group.
n represents 0 or 1. )
2)
The aqueous ink composition according to 1), wherein the content of the 1,2-alkanediol is 1% by mass to 20% by mass with respect to the total mass of the aqueous ink composition.
3)
The aqueous ink composition as described in 1) above, wherein the content of the 1,2-alkanediol is 5% by mass to 20% by mass with respect to the total mass of the aqueous ink composition.
4)
In the above formula (1), R ₁ is a carboxy group or a sulfo group, R ₂ is a hydrogen atom, R ₆ is a nitro group, a carboxy group, or a sulfo group, and n is 1. The water-based ink composition as described.
5)
In the above formula (1), R ₁ and R ₃ are sulfo groups, R ₄ is a hydrogen atom, R ₅ is a hydrogen atom, a carboxy group, or a sulfo group, and R ₆ is a nitro group, a carboxy group, or a sulfo group. a group, R ₇ is a hydrogen atom, n is an aqueous ink composition according to the above 1) is 1.
6)
The water-based ink composition according to any one of 1) to 3) above, wherein the 1,2-alkanediol is a 1,3-diol of a C3-C16 alkane.
7)
The aqueous ink composition according to any one of 1) to 3) or 6) above, wherein the 1,2-alkanediol is a 1,3-diol of a C3-C8 alkane.
8)
The above 1) to 3), wherein the 1,2-alkanediol is at least one 1,2-alkanediol selected from the group consisting of 1,2-hexanediol and 1,2-octanediol, or The water-based ink composition according to any one of 6) to 7) above.
9)
An ink jet recording method for performing recording by ejecting droplets of the water-based ink composition according to any one of 1) to 8) according to a recording signal and attaching the droplets to a recording material.
10)
The inkjet recording method according to 9) above, wherein the recording material is an information transmission sheet.
11)
A colored body colored with the water-based ink composition according to any one of 1) to 8) above.
12)
The inkjet printer with which the container containing the water-based ink composition as described in any one of said 1) -8) was loaded.

  According to the present invention, an aqueous ink composition capable of improving color developability can be provided.

In the present specification, “%” and “parts” including examples and the like are described on a mass basis unless otherwise specified. In the present specification, “CI” means “color index”.
In the present specification, for the sake of convenience, unless otherwise specified, the term “dye or salt thereof” is simply abbreviated as “dye” and means both “dye or salt thereof”.

The dye represented by the above formula (1) is a black dye.
In the above formula (1), R ₁ , R ₂ , R ₅ , R ₆ and R ₇ are each independently a hydrogen atom, a halogen atom, a cyano group, a hydroxy group, a carboxy group, a sulfo group, a sulfamoyl group, or a nitro group. , An alkoxy group which may have a substituent, an alkylsulfonyl group which may have a substituent, an alkyl group, an arylsulfamoylamino group which may have a substituent, and an alkylcarbonylamino group Represents a group selected from:
R ₃ and R ₄ are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a cyano group, a sulfo group, a carboxy group, a nitro group, an alkoxy group that may have a substituent, and an alkyl group. Represents a group.

  As said halogen atom, a chlorine atom, a bromine atom, or an iodine atom is mentioned, A chlorine atom or a bromine atom is preferable, and a chlorine atom is more preferable.

  Examples of the alkoxy group which may have a substituent include an alkoxy group which may have a sulfo group, a C1-C6 alkoxy group which may have a sulfo group is preferable, and has a sulfo group. The C1-C4 alkoxy group which may be sufficient is more preferable.

  Examples of the alkylsulfonyl group that may have a substituent include an alkylsulfonyl group that may have a hydroxy group, a C1-C6 alkylsulfonyl group that may have a hydroxy group is preferable, and a hydroxy group A C1-C4 alkylsulfonyl group which may have a hydrogen atom is more preferable.

As said alkyl group, a linear, branched or cyclic alkyl group is mentioned, A linear or branched thing is preferable and a linear thing is more preferable. The range of carbon number of the alkyl group is usually C1-C6, preferably C1-C4, more preferably C1-C3.
Specific examples thereof include linear C1-C6 alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl and n-hexyl; isopropyl, isobutyl, sec-butyl, t-butyl, isopentyl and isohexyl. Branched C1-C6 alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and the like cyclic C1-C6 alkyl groups; and the like.

Examples of the arylsulfamoylamino group that may have a substituent include a phenylsulfamoylamino group that may have a substituent.
Moreover, the phenyl sulfamoylamino group which may have an alkyl group as this substituent is preferable. Examples of the alkyl group at this time include the same groups as those described above, including preferable ones.

  Examples of the alkylcarbonylamino group include an alkylcarbonylamino group having the same alkyl group as the alkyl group, including those preferable for the alkyl group.

Among the above, as R ₁ and R ₂ ,
At least one is preferably a group other than a hydrogen atom;
More preferably, at least one is a carboxy group, a sulfo group or an unsubstituted alkoxy group, and the other is a hydrogen atom or a sulfo group;
More preferably, one is a sulfo group and the other is a hydrogen atom.
Among these, a configuration in which “one” is read as R ₁ and “the other” as R ₂ is particularly preferable.

Of the above, as R ₅ , R ₆ and R ₇ ,
A group other than at least one hydrogen atom is preferred;
A group in which at least one of them is selected from a carboxy group, a sulfo group, and a nitro group is more preferable;
More preferably, at least one is a hydrogen atom, and one of the remaining two is a carboxy group, a sulfo group, or a nitro group, and the other is a hydrogen atom or a nitro group;
It is particularly preferable that at least one is a hydrogen atom and one of the remaining two is a sulfo group and the other is a hydrogen atom or a nitro group.
Of these, a configuration in which “of one of the remaining two” is read as R ₆ and “the other” as R ₅ is particularly preferable.

Among the above, as R ₃ and R ₄ ,
At least one is preferably a group other than a hydrogen atom;
More preferably, at least one is a sulfo group, an alkoxy group which may have a substituent, or an alkyl group, and the other is a hydrogen atom, a sulfo group or an alkyl group;
More preferably, at least one is a sulfo group, the other is a hydrogen atom, or one is an alkoxy group which may have a substituent, and the other is an alkyl group;
One is particularly preferably a sulfo group and the other a hydrogen atom.

In the above formula (1), examples of the substitution position of the nitro group, R _{1 to} R ₇ , and — (SO ₃ H) n group whose substitution positions are not specified include the following positions.

[Substitution positions of R ₁ , nitro group, and R ₂ ]
As for the substitution position of each group on the benzene ring substituted by these, the substitution positions of the following (a) to (c) are exemplified with the substitution position of the azo group bonded to the benzene ring as the first position.
(A) R ₁ is in position 2, the nitro group is in position 4, and R ₂ is in position 5.
(B) R ₁ is 4-position, nitro group is 2-position, and R ₂ is 5-position.
(C) R ₁ is in position 2, the nitro group is in position 5, and R ₂ is in position 4.
Of these, (a) or (b) is preferred, and (a) is more preferred.

[Substitution positions of R ₃ and R ₄ ]
The substitution position of each group on the benzene ring to which these are substituted is such that R ₃ is the 3-position, with the substitution position of the azo group binding to the benzene ring and binding to the benzene ring having R _{5 to} R ₇ as the 1-position. R ₄ is preferably substituted at the 6-position.

[Substitution positions of R ₅ , R ₆ and R ₇ ]
Examples of the substitution position of each group on the benzene ring substituted by these include the substitution positions (a) to (d) below, with the substitution position of the azo group bonded to the benzene ring being the first position.
(A) R ₅ is 2nd, R ₆ is 4th, and R ₇ is 5th.
(B) R ₅ is 3rd, R ₆ is 5th, and R ₇ is 4th.
(C) R ₅ is 2nd, R ₆ is 5th, R ₇ is 4th.
(D) R ₅ is 3rd, R ₆ is 4th, and R ₇ is 6th.
Of these, (a) is preferred.

[Substitutional position of — (SO ₃ H) n group]
In the naphthalene ring substituted by the — (SO ₃ H) n group, the substitution position of the hydroxy group is the 1st position, the substitution position of the sulfo group whose substitution position is specified is the 3rd position, and the — (SO ₃ H) n group is 5 It is preferable to substitute at the position.

Each group represented as R ₁ to R ₇ in the dye represented by the above formula (1) and each group whose substitution position including a nitro group and a “— (SO ₃ H) n group” is not specified Regarding the substitution position, a combination of preferable ones is more preferable, and a combination of more preferable ones is further preferable. The same applies to combinations of preferable ones and combinations of preferable ones and more preferable ones.

  Specific examples of the compound represented by the above formula (1) are listed in Tables 1 to 3 below. However, the compound represented by the above formula (1) is not limited thereto.

  Among the dyes represented by the above formula (1), dyes represented by the following formula (22), formula (23) or formula (26) are particularly preferred, and among these, formula (22) is most preferred.

  The dye represented by the above formula (1) can be synthesized by the method described in Patent Document 3, for example.

The dye represented by the above formula (1) may be used as a salt.
Examples of the salt of the dye represented by the above formula (1) include salts formed with inorganic or organic cations. Among them, specific examples of inorganic salts include salts formed with cations of elements of Group 1 or Group 2 of the periodic table of elements, and ammonium salts. Among these, preferred inorganic salts are lithium, sodium, potassium and ammonium salts.
Examples of the organic cation salt include, but are not limited to, salts formed with compounds represented by the following formula (16).

In the above formula (16), Z ¹ , Z ² , Z ³ and Z ⁴ each independently represent a hydrogen atom, an alkyl group, a hydroxyalkyl group or a hydroxyalkoxyalkyl group, but Z ¹ , Z ² , Z All of ³ and Z ⁴ are not hydrogen atoms.

As the alkyl group of Z ¹ , Z ² , Z ³ and Z ^{4 in} the formula (16), a C1-C4 alkyl group is preferable, and specific examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec -Butyl, t-butyl and the like.
Examples of hydroxyalkyl groups include hydroxy C1-C4 alkyl groups such as hydroxymethyl, hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 4-hydroxybutyl, 3-hydroxybutyl, 2-hydroxybutyl and the like.
Examples of hydroxyalkoxyalkyl groups include hydroxyethoxymethyl, 2-hydroxyethoxyethyl, 3-hydroxyethoxypropyl, 2-hydroxyethoxypropyl, 4-hydroxyethoxybutyl, 3-hydroxyethoxybutyl, 2-hydroxyethoxybutyl, etc. A hydroxy C1-C4 alkoxy C1-C4 alkyl group is mentioned, Among these, a hydroxyethoxy C1-C4 alkyl group is preferable. Particularly preferred are a hydrogen atom; methyl; a hydroxy C1-C4 alkyl group such as hydroxymethyl, hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 4-hydroxybutyl, 3-hydroxybutyl, 2-hydroxybutyl; And hydroxyethoxy C1-C4 alkyl groups such as ethoxymethyl, 2-hydroxyethoxyethyl, 3-hydroxyethoxypropyl, 2-hydroxyethoxypropyl, 4-hydroxyethoxybutyl, 3-hydroxyethoxybutyl, 2-hydroxyethoxybutyl and the like. .

Specific examples of Z ¹ , Z ² , Z ³ and Z ^{4 in} the formula (16) are shown in the following Table 4, but the compound represented by the formula (16) is not limited to these specific examples.

  As an example of an organic cation salt, for example, a monoethanolamine salt, a diethanolamine salt, a triethanolamine salt, a monoisopropanolamine salt, a diisopropanolamine salt, or a triisopropanolamine salt is preferably exemplified.

The aqueous ink composition contains at least a dye represented by the above formula (1) and 1,2-alkanediol. By containing this 1,2-alkanediol, the effect of improving the color developability of the dye represented by formula (1) can be obtained.
Examples of 1,2-alkanediol include 1,2-diol having a linear, cyclic, or branched alkane moiety. The 1,2-alkanediol is usually a C3-C16 alkane, preferably a C3-C8 alkane 1,2-diol.
Specific examples of 1,2-alkanediol include, for example, 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, , 2-octanediol, 1,2-nonanediol, 1,2-decanediol, 1,2-tetradecanediol, 1,2-hexadecanediol and the like; 1,2-cyclohexanediol, 1,2 -1,2-alkanediols such as cyclic ones such as cyclooctanediol and 1,2-cyclohexanedimethanol; These can be used alone or in combination. The 1,2-alkanediol that can be used in the present invention is not limited to the specific examples described above, and any one can be used as long as it satisfies this requirement.

Among the 1,2-alkanediols, at least one 1,2-alkanediol selected from the group consisting of 1,2-hexanediol and 1,2-octanediol is particularly preferable.
The content of 1,2-alkanediol is usually preferably 1% to 20% and 5% to 20% with respect to the total mass of the aqueous ink composition.

  The above water-based ink composition further contains a toning dye other than the above formula (1) within the range not impairing the effect obtained by the present invention for the purpose of setting the image recorded thereby to a desired hue. be able to. The type of the toning dye is not particularly limited. For example, at least one dye selected from the group consisting of reactive dyes, acid dyes, and direct dyes is preferable, and selected from the group consisting of acid dyes and direct dyes. More preferred are at least one dye.

  Specific examples of reactive dyes for toning include C.I. I. Yellow dyes such as Reactive Yellow 2, 3, 18, 81, 84, 85, 95, 99, 102; I. Orange dyes such as Reactive Orange 5, 9, 12, 13, 35, 45, 99; I. Brown dyes such as Reactive Brown 2, 8, 9, 17, 33; I. Reactive Red 3, 3: 1, 4, 13, 24, 29, 31, 33, 125, 151, 206, 218, 226, 245, and the like.

  Specific examples of the acid dye for toning include C.I. I. Acid Yellow 1, 3, 11, 17, 18, 19, 23, 25, 36, 38, 40, 40: 1, 42, 44, 49, 59, 59: 1, 61, 65, 72, 73, 79, Yellow dyes such as 99, 104, 110, 159, 169, 176, 184, 193, 200, 204, 207, 215, 219, 219: 1, 220, 230, 232, 235, 241, 242, 246; C. I. Acid Orange 3, 7, 8, 10, 19, 24, 51, 56, 67, 74, 80, 86, 87, 88, 89, 94, 95, 107, 108, 116, 122, 127, 140, 142, Orange dyes such as 144, 149, 152, 156, 162, 166, 168; I. Acid Brown 2, 4, 13, 14, 19, 28, 44, 123, 224, 226, 227, 248, 282, 283, 289, 294, 297, 298, 301, 355, 357, 413, etc. A dye; I. Acid Red 1, 6, 8, 9, 13, 18, 27, 35, 37, 52, 54, 57, 73, 82, 88, 97, 97: 1, 106, 111, 114, 118, 119, 127, 131, 138, 143, 145, 151, 183, 195, 198, 211, 215, 217, 225, 226, 249, 251, 254, 256, 257, 260, 261, 264, 265, 266, 274, 276, Red dyes such as 277, 289, 296, 299, 315, 318, 336, 337, 357, 359, 361, 362, 364, 366, 399, 407, 415; I. A black dye such as Acid Black 2;

  Specific examples of direct dyes for toning include C.I. I. Direct Yellow 8, 11, 12, 21, 28, 33, 39, 44, 49, 50, 85, 86, 87, 88, 89, 98, 100, 110, 132, 142, 144, 146, etc. A dye; I. Orange dyes such as Direct Orange 17, 26, 39, 102; I. Direct Red 2, 4, 6, 9, 17, 23, 26, 28, 31, 39, 54, 55, 57, 62, 63, 64, 65, 68, 72, 75, 76, 79, 80, 81, 83 83: 1, 84, 89, 92, 95, 99, 111, 141, 173, 180, 184, 207, 211, 212, 214, 218, 221, 223, 224, 225, 226, 227, 232, 233 , 240, 241, 242, 243, 247, etc .;

  Among the above dyes, C.I. I. Direct Yellow 86, 132, 142; C.I. I. Direct Orange 17, 39; C.I. I. Direct Red 80, 84, 227; C.I. I. Direct Brown 106, 125, 195; C.I. I. Acid Red 249, 254; C.I. I. Acid Black 2; at least one dye selected from the group consisting of Acid Black 2 is preferable as the toning dye, and C.I. I. An orange dye selected from Direct Orange, and C.I. I. More preferred is at least one dye selected from the group consisting of Acid Black 2.

  It is difficult to determine the content of the above-mentioned dye for toning. However, as a guideline, the total amount of dyes for toning is usually 50% to 300%, preferably 50, based on the content of the dye represented by formula (1) in the total mass of the ink composition. % To about 200%.

When the above dyes including the dye represented by the formula (1) are used for ink jet recording, it is preferable to remove inorganic impurities which are generally mixed when obtained as a commercial product by a purification operation. Examples of such a purification operation include a purification method using a reverse osmosis membrane; or a purification method in which the dye base is stirred in a mixed solvent of alcohol such as methanol and water, separated by filtration, and dried.
Examples of inorganic impurities include chlorides (for example, sodium chloride) and sulfides (for example, sodium sulfate) of Group 1 and / or Group 2 elements of the periodic table of elements. When purification is performed, the total content of inorganic impurities in the total mass of the aqueous ink composition is preferably 100 ppm or less, and more preferably 50 ppm or less. The lower limit may be equal to or lower than the detection limit of the detection device, that is, 0%.

The water-based ink composition can contain a water-soluble organic solvent and an ink preparation agent as necessary, as long as the effects of the present invention are not impaired.
The surface tension of the aqueous ink composition is usually 25 to 70 mN / m, preferably 25 to 60 mN / m.
The viscosity of the water-based ink composition is usually 30 mPa · s or less, preferably 20 mPa · s or less, and the lower limit is about 1 mPa · s.

Examples of the water-soluble organic solvent include C1-C4 alkanols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol and tert-butanol; N, N-dimethylformamide or N, N-dimethylacetamide Carboxylic acid amides; lactams such as 2-pyrrolidone and N-methylpyrrolidin-2-one; cyclics such as 1,3-dimethylimidazolidin-2-one and 1,3-dimethylhexahydropyrimido-2-one Ureas; ketones or ketoalcohols such as acetone, methyl ethyl ketone, 2-methyl-2-hydroxypentan-4-one; cyclic ethers such as tetrahydrofuran, dioxane; ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol 1,6-hex Monomers, oligomers or polyalkylene glycols or thioglycols having C2-C6 alkylene units such as lenglycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, thiodiglycol, dithiodiglycol and the like; Polyol (triol) such as glycerin, hexane-1,2,6-triol; ethylene glycol monomethyl ether or ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether butyl carbitol or triethylene glycol monomethyl ether Or triethylene glycol mono C1-C4 alkyl ethers of polyhydric alcohols such as Chirueteru; .gamma.-butyrolactone, or dimethyl sulfoxide and the like.
Among these water-soluble organic solvents, 2-pyrrolidone, glycerin, diglycerin, butyl carbitol, ethylene glycol, diethylene glycol, propylene glycol, and triethylene glycol are preferable, and 2-pyrrolidone, glycerin, and diethylene glycol are more preferable. These organic solvents can be used alone or in combination of two or more.

  The content of the water-soluble organic solvent is usually 0 to 50%, preferably 10 to 50%, more preferably 25 to 50% with respect to the total mass of the water-based ink composition.

  Examples of the ink preparation agent include antiseptic / antifungal agents, pH adjusting agents, chelating reagents, rust preventive agents, water-soluble ultraviolet absorbers, water-soluble polymer compounds, dye-dissolving agents, and antioxidants.

  Examples of the preservative include organic sulfur, organic nitrogen sulfur, organic halogen, haloallylsulfone, iodopropargyl, N-haloalkylthio, (double) nitrile, pyridine, 8-oxyquinoline, Benzothiazole, isothiazoline, dithiol, pyridine oxyd, nitropropane, organotin, phenol, quaternary ammonium salt, triazine, thiazine, anilide, adamantane, dithiocarbamate, brominated indanone , Benzyl bromacetate compounds, inorganic salt compounds and the like. An example of the organic halogen compound is sodium pentachlorophenol. As a pyridine oxydide-type compound, 2-pyridinethiol-1-oxide sodium is mentioned, for example. An example of the inorganic salt compound is anhydrous sodium acetate. Examples of isothiazoline compounds include 1,2-benzisothiazolin-3-one, 2-n-octyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 5- Chloro-2-methyl-4-isothiazolin-3-one magnesium chloride, 5-chloro-2-methyl-4-isothiazolin-3-one calcium chloride, 2-methyl-4-isothiazolin-3-one calcium chloride and the like It is done.

  Examples of the antifungal agent include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, p-hydroxybenzoic acid ethyl ester, 1,2-benzisothiazolin-3-one and salts thereof. When it contains an antifungal agent, it is preferably used in an amount of 0.02 to 1% based on the total mass of the aqueous ink composition.

  Other antiseptic / antifungal agents include sodium sorbate and sodium benzoate.

  As the pH adjuster, any substance can be used as long as it can control the pH of the ink within a range of about 5 to 11 without adversely affecting the prepared ink. Examples thereof include, for example, alkanolamines such as diethanolamine, triethanolamine and N-methyldiethanolamine; hydroxides of alkali metals such as lithium hydroxide, sodium hydroxide and potassium hydroxide; ammonium hydroxide (ammonia); or Examples thereof include alkali metal carbonates such as lithium carbonate, sodium carbonate, sodium hydrogen carbonate and potassium carbonate; inorganic bases such as potassium acetate, sodium silicate and disodium phosphate;

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

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

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

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

  Examples of the dye solubilizer include ε-caprolactam, ethylene carbonate, urea and the like. Among these, urea is preferable.

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

In the preparation of the aqueous ink composition, there is no particular limitation on the order in which the additives such as the colorant, the water-soluble organic solvent, and the ink preparation agent are dissolved.
The water used for the preparation of the ink composition is preferably water with few inorganic impurities such as ion exchange water and distilled water.
Further, if necessary, after the ink composition is prepared, fine filtration can be performed using a membrane filter or the like to remove impurities in the ink composition. In particular, when the ink composition is used for ink jet recording, it is preferable to perform microfiltration. The pore size of the filter used for microfiltration is usually 1 μm to 0.1 μm, preferably 0.8 μm to 0.1 μm.

  The aqueous ink composition can be used in various fields. As an example, it can be used for writing, water-based printing, information recording, and the like, and is particularly preferably used for inkjet recording.

  The ink jet recording method is a method of recording by ejecting droplets of the water-based ink composition according to a recording signal and attaching the droplets to a recording material.

  When performing the ink jet recording, an ink jet printer is generally used. There is no restriction | limiting in particular about the ink nozzle etc. with which the inkjet printer is provided, According to the objective, it can select suitably. For example, a charge control method that ejects ink using electrostatic attraction force; a drop-on-demand method (pressure pulse method) that uses the vibration pressure of a piezo element; Acoustic ink jet method that discharges ink using pressure; a known ink jet recording method such as thermal ink jet that heats ink to form bubbles and uses the generated pressure, for example, bubble jet (registered trademark) method; be able to. The ink jet recording method is a method in which a large amount of ink having a small dye content called photo ink is ejected in a small volume; a plurality of inks having substantially the same hue and different dye contents are used for image quality. Or a method using a color ink and a colorless and transparent ink in combination.

  By using the above water-based ink composition as a black ink and combining it with each ink composition such as magenta, cyan, yellow, green, blue (or violet), and red (or orange) as necessary, full color It is also possible to obtain a recorded image. In this case, the ink composition of each color can be poured into each container, and the container can be loaded into a predetermined position of the ink jet printer and used for ink jet recording in the same manner as the container containing the aqueous ink composition. it can.

The colored body means a substance colored with the water-based ink composition, preferably a substance colored by the inkjet recording method.
The substance is not particularly limited as long as it can be colored by the aqueous ink composition. Among such substances, recording materials such as information transmission sheets such as paper and film; fibers and fabrics (cellulose, nylon, wool, etc.); leather; base materials for color filters;
Examples of the information transmission sheet include those that have been surface-treated, specifically, those in which an ink receiving layer is provided on a substrate such as paper, synthetic paper, and film, and those in which an ink receiving layer is not particularly provided. It is done. The ink receiving layer is formed by, for example, impregnating or coating the base material with a cationic polymer; a porous white inorganic material capable of absorbing a colorant in an aqueous ink composition such as porous silica, alumina sol, or special ceramics; It is provided by coating the surface of the substrate together with a hydrophilic polymer such as alcohol or polyvinylpyrrolidone; Those provided with such an ink receiving layer are usually called ink jet dedicated paper (film), glossy paper (film) and the like. Specific examples thereof include, for example, Pictrico manufactured by Asahi Glass Co., Ltd .; professional photo paper manufactured by Canon Inc., super photo paper, matte photo paper, glossy gold, platinum grade; photographic paper manufactured by Seiko Epson Corporation ( Glossy), photo matte paper, photographic paper Crispier (high gloss); Premium Plus Photo Paper, Premium Glossy Film, Photo Paper, Advanced Photo Paper manufactured by Hewlett-Packard Japan; Photo-like QP manufactured by Konica Corporation; Examples include painting photo finishing Pro; manufactured by FUJIFILM Corporation.
On the other hand, examples of the information transmission sheet that is not particularly provided with an ink receiving layer include plain paper, high-quality paper, and coated paper. Many types of plain paper are commercially available depending on the application. Examples of commercially available plain paper include: Double-sided fine plain paper manufactured by Seiko Epson Corporation; Color plain paper manufactured by Canon Inc .; Multipurpose Paper, All-in-One Printing manufactured by Hewlett Packard Co., Ltd. Paper: Matte paper for inkjet manufactured by Mitsubishi Paper Industries Co., Ltd., trade name DL-9084; Premium multi-purpose paper 4024 manufactured by Xerox Co., Ltd .; Npi foam NEXT-IJ, Npi foam manufactured by Nippon Paper Industries Co., Ltd .; Manufactured by Co., Ltd., OKH-J off; In addition, PPC (plain paper copy) paper and the like are plain paper.

The aqueous ink composition is very clear on the recording material, has high saturation and printing density, and gives a black recorded image with an ideal hue. Further, the aqueous black ink composition of the present invention has very good storage stability without solid precipitation, physical property change, hue change and the like after long-term storage.
The aqueous black ink composition of the present invention is used for inkjet recording and writing instruments, and even when used as an inkjet ink, solid precipitation due to drying of the ink composition near the nozzle is very unlikely to occur. ) Is not blocked. In addition, the aqueous black ink composition of the present invention uses a continuous ink jet printer, and when the ink is recirculated at a relatively long time interval or used intermittently by an on-demand ink jet printer, Does not cause changes in physical properties.
Furthermore, the image recorded with the water-based ink composition of the present invention can particularly improve color developability.

  EXAMPLES The present invention will be described more specifically with reference to examples. However, the present invention is not limited to the examples. Moreover, in each structural formula of the compound obtained in the Example, acidic functional groups, such as a sulfo group, were described in the form of a free acid.

[(A) Synthesis of Dye]
According to the method described in Patent Document 3, dyes represented by the above formula (22), formula (23) and formula (26) were synthesized.

[(B) Preparation of aqueous ink composition]
[Examples 1 to 9 and Comparative Examples 1 to 8]
The components described in Tables 5 and 6 below were mixed, the total amount was adjusted to 100 parts with water, and then stirred for about 1 hour to obtain a solution. The obtained solution was filtered through a 0.45 μm membrane filter (trade name cellulose acetate filter paper manufactured by Advantech) to prepare an aqueous ink composition for evaluation test. In addition, the numerical value of each component in the following table means “part”.

Moreover, the abbreviations in the following table have the following meanings.
AB2: C.I. I. Acid Black2.
DO39: C.I. I. Direct Orange 39.
GL: glycerin.
DEG: Diethylene glycol.
2-PY: 2-pyrrolidone.
1,2-HD: 1,2-hexanediol.
1,6-HD: 1,6-hexanediol.
1,5-PD: 1,5-pentanediol.
1,2-OD: 1,2-octanediol.
TEA: triethanolamine.
Water: Ion exchange water.

EAY

EAY

[(C) Inkjet recording]
100%, 80%, 60%, 40%, and 20% concentration of the aqueous ink composition prepared in each example and comparative example on the following three types of plain paper using an inkjet printer manufactured by EPSON Co., Ltd., trade name PX105 An image pattern was prepared so as to obtain the following five gradations, and ink jet recording was performed so as to obtain a dark to light gradation, and a gradation colored body was obtained. This was used as a test piece, and the following evaluation test was performed.
Plain paper 1: Nippon Paper Industries Co., Ltd., Npi Form NEXT-IJ
Plain paper 2: Oji Paper Co., Ltd., OKH-J off plain paper 3: Nippon Paper Industries Co., Ltd., Npi form

[(D) Colorimeter and colorimetric conditions]
In the following evaluation tests, color measurement was performed using the following colorimeters and colorimetric conditions.
Colorimeter:
Product name SpectroEye manufactured by GRETAG-MACBETH.
Colorimetric conditions:
The density standard is ANSI A, the viewing angle is 2 °, and the light source is D50.

[(E) Color development evaluation test]
The 40% density portion of each of the Examples and Comparative Examples obtained in “(C) Inkjet recording” was measured for color, and the color development was evaluated according to the following four criteria.
A: 0.6 or more.
B: 0.5 or more and less than 0.6.
C: 0.4 or more and less than 0.5.
D: Less than 0.4.
The test results are shown in Tables 7 and 8 below.

  As is clear from the results in Tables 7 and 8, the aqueous ink compositions of the respective examples containing 1,2-alkanediol are the aqueous inks of the comparative examples containing alkanediols other than 1,2-alkanediol. It has been revealed that the composition has a very remarkable effect of improving color developability.

  Since the water-based ink composition of the present invention is very excellent in color developability of a recorded image, it is very suitably used for various recording applications, particularly inkjet recording.

Claims (12)

A water-based ink composition containing at least a dye represented by the following formula (1) or a salt thereof and 1,2-alkanediol.

(In the above formula (1),
R ₁ , R ₂ , R ₅ , R ₆ and R ₇ each independently have a hydrogen atom, a halogen atom, a cyano group, a hydroxy group, a carboxy group, a sulfo group, a sulfamoyl group, a nitro group, or a substituent. Represents a group selected from the group consisting of an alkoxy group which may have a substituent, an alkylsulfonyl group which may have a substituent, an alkyl group, an arylsulfamoylamino group which may have a substituent, and an alkylcarbonylamino group .
R ₃ and R ₄ are each independently selected from the group consisting of a hydrogen atom, a halogen atom, a cyano group, a sulfo group, a carboxy group, a nitro group, an optionally substituted alkoxy group, and an alkyl group. Represents a group.
n represents 0 or 1. )   The aqueous ink composition according to claim 1, wherein the content of the 1,2-alkanediol is 1% by mass to 20% by mass with respect to the total mass of the aqueous ink composition.   2. The aqueous ink composition according to claim 1, wherein the content of the 1,2-alkanediol is 5% by mass to 20% by mass with respect to the total mass of the aqueous ink composition. In the above formula (1), R ₁ is a carboxy group or a sulfo group, R ₂ is a hydrogen atom, R ₆ is a nitro group, a carboxy group, or a sulfo group, and n is 1. The water-based ink composition as described. In the above formula (1), R ₁ and R ₃ are sulfo groups, R ₄ is a hydrogen atom, R ₅ is a hydrogen atom, a carboxy group, or a sulfo group, and R ₆ is a nitro group, a carboxy group, or a sulfo group. The water-based ink composition according to claim 1, which is a group, R ₇ is a hydrogen atom, and n is 1.   The aqueous ink composition according to any one of claims 1 to 3, wherein the 1,2-alkanediol is a 1,3-diol of a C3-C16 alkane.   The aqueous ink composition according to any one of claims 1 to 3, wherein the 1,2-alkanediol is a 1,3-diol of a C3-C8 alkane.   The 1,2-alkanediol is at least one 1,2-alkanediol selected from the group consisting of 1,2-hexanediol and 1,2-octanediol. Item 8. The aqueous ink composition according to any one of Items 6 to 7.   An ink jet recording method for performing recording by ejecting the droplets of the water-based ink composition according to any one of claims 1 to 8 according to a recording signal and attaching the droplets to a recording material.   The inkjet recording method according to claim 9, wherein the recording material is an information transmission sheet.   The colored body colored with the water-based ink composition as described in any one of Claims 1-8.   An ink jet printer loaded with a container containing the water-based ink composition according to claim 1.