JP2012036256A - Ink composition and colored material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink composition having excellent light resistance without deteriorating clarity which is a feature of a xanthene dye.SOLUTION: There is provided the ink composition having at least one of xanthene dye and at least one of bivalent copper compound, and the excellent light resistance without deteriorating the clarity of recorded images by using the ink composition having the maximum absorbance of a 0.1 mass% aqueous solution of the bivalent copper compound of ≤0.2 within the wavelength range of 400-600 nm in measurement of the absorbance with a spectrophotometer.

Description

  The present invention relates to an ink composition containing at least one xanthene dye and a copper compound, a recording method using the ink composition, and a colored body colored with the ink composition.

  Among various color recording methods, various ink ejection methods have been developed in a recording method using an ink jet printer, which is one of the representative methods, that is, an ink jet recording method. These all generate ink (small) droplets and attach them to various recording materials (paper, film, fabric, etc.) to perform recording. In this method, since the recording head and the recording material do not come into contact with each other, there is almost no sound generation and it is quiet. In addition, due to the features that it is easy to downsize, speed up, and colorize, it has been spreading rapidly in recent years and is expected to grow greatly in the future.

  As a method of recording an image or character information on a color display of a computer in color by an ink jet printer, generally, four colors of ink of yellow (Y), magenta (M), cyan (C), and black (K) are used. The method of recording by subtractive color mixing is mentioned. In order to reproduce the hue of an additive color mixture image of red (R), green (G), and blue (B) on a CRT display, etc. as faithfully as possible by subtractive color mixture images, each of Y, M, and C is as much as possible. It is desirable to have a hue close to that of the standard and to be clear.

  Conventionally, water-based inks in which water-soluble dyes are dissolved in water-based media have been used as inks such as fountain pens and felt-tip pens and inks for inkjet recording. In these water-based inks, a water-soluble organic solvent is generally added to prevent clogging of the ink at the pen tip or the ink discharge nozzle. In these conventional inks, a recording image with sufficient density is provided, the clogging of the pen tip and the nozzle does not occur, the drying property on the recording material is good, the bleeding is small, and the storage stability. The recorded image is required to have fastness such as water resistance, light resistance, moisture resistance and gas resistance.

For water resistance, organic or inorganic fine particles such as porous silica, cationic polymers, alumina sol or special ceramics are coated on the surface of paper together with PVA resin, etc., and an ink image-receiving layer is provided on the recording material. Has been improved.
Technology for significantly improving light resistance has not yet been established, and in particular, among the four primary colors Y, M, C, and K, many of magenta dyes have inherently low light resistance, so that improvement is an important issue. It is one.
Moisture resistance refers to resistance to a phenomenon in which a dye on a recording material or in a recording material oozes around a colored image when the colored recording material is stored in a high humidity atmosphere. . When the bleeding of the pigment occurs, the image quality is remarkably deteriorated particularly in the high-definition image quality of the photographic tone. Therefore, it is important to reduce such bleeding as much as possible.
Gas resistance refers to resistance to a phenomenon in which ozone gas or the like having an oxidizing action existing in the air acts on a dye on the recording paper or in the recording paper to cause the recorded image to discolor. In addition to ozone gas, examples of the oxidizing gas having this kind of action include NOx and SOx. However, among these oxidizing gases, ozone gas is regarded as a main causative substance that promotes the discoloration phenomenon of ink jet recorded images, and particularly, ozone gas resistance is regarded as important. An ink receiving layer is provided on the surface of the exclusive inkjet paper capable of obtaining photographic image quality in order to expedite ink drying and to reduce bleeding at high image quality. In many cases, the ink receiving layer is made of a material such as a porous white inorganic material. In such a recording paper, discoloration due to ozone gas or the like is noticeable. Since this discoloration phenomenon due to the oxidizing gas is characteristic of an ink jet recording image, improvement of gas resistance, particularly ozone gas resistance, is one of the important problems in ink jet recording.

  Due to the recent development of inkjet recording technology, the recording (printing) speed has been remarkably improved. For this reason, there is a movement to use an inkjet printer in the same manner as a laser printer using electronic toner for printing a document on plain paper, which is the main use in an office environment. Inkjet printers have the advantage that the type of recording paper is not limited; the price of the machine is relatively low; and are particularly popular in small to medium-sized office environments such as SOHO. As described above, when an inkjet printer is used for recording on plain paper, hue and image (printing) density tend to be more important among various qualities required for recorded matter.

Xanthene dyes are known as one of the magenta dyes used in water-soluble inks for ink jet recording. This dye is known to have excellent sharpness, hue, and image density, but poor lightfastness. For this reason, it is possible to provide a xanthene dye that gives a recorded image having excellent sharpness, hue, image density, and fastness such as light resistance and ozone gas resistance, and an ink composition containing the same. Is one of the market demands.
Patent Document 1 discloses an ink-jet ink formulation containing a mixture of a rhodamine dye, which is one of xanthene dyes, and a metal-containing magenta dye.
Patent Document 2 discloses C.I., a xanthene dye. I. Acid Red 52 and C.I. I. An ink containing at least one of Acid Red 289, an anthrapyridone dye, and an aqueous medium is disclosed.

JP 2003-238875 A JP 2004-182996 A

  An object of the present invention is to provide an ink composition that provides a recorded image with significantly improved light resistance without impairing the excellent sharpness of a xanthene dye.

In order to solve the above-mentioned problems, the present inventors have intensively studied, and as a result, an ink composition containing at least one kind of xanthene dye and at least one kind of copper compound having a specific absorbance solves the above problems. The present invention has been found and completed.
That is, the present invention
1)
An ink composition comprising at least one xanthene dye and at least one divalent copper compound, and
An ink composition having a maximum absorbance of a 0.1% by mass aqueous solution of the divalent copper compound in an absorbance measurement using a spectrophotometer of 0.2 or less in a wavelength range of 400 nm to 600 nm;
2)
The ink composition according to 1), wherein the xanthene dye is a dye represented by the following formula (1), an isomer at a cation position thereof, or a salt thereof:

[In Formula (1),
R ^{1 to} R ⁴ are each independently a hydrogen atom; a C1-C10 alkyl group; a C1-C10 alkyl group having a group selected from the group consisting of a hydroxy group, a carboxy group, and a sulfo group as a substituent; a phenyl group; A phenyl group having a group selected from the group consisting of a hydroxy group, a carboxy group, a sulfo group, a sulfamoyl group, a C1-C4 alkyl group, a C1-C4 alkoxy group and a halogen atom as a substituent;
R ⁵ represents a sulfo group, a carboxy group, or a C1-C4 alkoxycarbonyl group,
R ⁶ represents a hydrogen atom; a C1-C10 alkyl group; a C1-C10 alkyl group having a group selected from the group consisting of a hydroxy group, a carboxy group, and a sulfo group as a substituent; a sulfo group; a carboxy group; a sulfamoyl group; A group; or a halogen atom;
R ⁷ and R ⁸ each independently represent a hydrogen atom or a C1-C10 alkyl group,
R ⁹⁻ represents a halogen anion, hydroxide, acetate anion, tetrafluoroborate anion, hexafluorophosphate anion, sulfate anion, or toluenesulfonate anion.
However, when the dye represented by the formula (1) forms a salt in the molecule, R ⁹⁻ does not exist. ],

3)
Ink composition as described in said 1) or 2) whose total mass of the xanthene dye contained in an ink composition is 0.5-20 mass% with respect to the total mass of this ink composition,
4)
4. The content of the copper compound contained in the ink composition is 0.01 to 10% by mass in terms of the atomic weight of copper with respect to the total mass of the ink composition. 5. Item 4. The ink composition according to item.
5)
Any one of 1) to 4) above, wherein the divalent copper compound is copper acetate, copper chloride, copper sulfate, copper hydroxide, or N, N, N ′, N′-ethylenediaminetetraacetate copper or a salt thereof. The ink composition according to Item,
6)
In the dye represented by the formula (1),
R ¹ is a C1-C10 alkyl group; or a phenyl group having, as a substituent, a group selected from the group consisting of a sulfo group and a C1-C4 alkyl group;
R ² is a hydrogen atom or a C1-C10 alkyl group,
R ³ is a hydrogen atom; a C1-C10 alkyl group; or a phenyl group having a C1-C4 alkyl group as a substituent;
R ⁴ is a hydrogen atom or a C1-C10 alkyl group,
R ⁵ is a sulfo group, a carboxy group, or a C1-C4 alkoxycarbonyl group,
R ⁶ is a hydrogen atom or a sulfo group,
R ⁷ and R ⁸ are each independently a hydrogen atom or a C1-C10 alkyl group,
The ink composition according to any one of claims 2 to 5, wherein R ^9- is a halogen anion.
However, when the dye represented by the formula (1) forms a salt in the molecule, R ⁹⁻ does not exist.
7)
The xanthene dye is C.I. I. Acid Red 289, or C.I. I. The ink composition according to 1) to 6), which is Acid Red 52,
8)
C1-C10 alkyl carboxylic acid; C1-C10 alkyl carboxylic acid having a hydroxy group; C1-C10 alkyl dicarboxylic acid; iminodiacetic acid; N-hydroxyiminodiacetic acid; C1 in which an oxygen atom may be inserted in the C1-C10 moiety -C10 polyhydric alcohol; C1-C10 polyhydric alcohol C1-C4 alkyl ether in which an oxygen atom may be inserted in the C1-C10 moiety; crown ether; saccharide; ammonia; C1-C10 alkylamine; A C1-C10 alkylamine having a group selected from the group consisting of a group, a carboxy group and a sulfo group; a C1-C10 alkylenediamine; 1,2-cyclohexylenediamine; a C1-C10 alkylenediamine having a carboxy group; Carboxy C1-C4 A Wherein 1) to 7 The ink composition according to any one of) further contains at least one compound selected from the group consisting of,; C1-C10 alkylene diamines substituted by Kill group
9)
The ink composition according to any one of 1) to 8), further comprising a water-soluble organic solvent,
10)
The ink composition according to any one of 1) to 9) used for inkjet recording,
11)
An ink jet recording method for performing recording by ejecting droplets of the ink composition according to any one of 1) to 10) according to a recording signal and attaching the droplets to a recording material;
12)
The inkjet recording method according to 11), wherein the recording material is an information transmission sheet,
13)
The inkjet recording method according to 12), wherein the information transmission sheet is a sheet having an ink receiving layer containing plain paper or a porous white inorganic substance;
14)
A colored body colored with the ink composition according to any one of 1) to 10),
15)
A colored body colored by the inkjet recording method of 11),
16)
An inkjet printer in which a container containing the ink composition according to any one of 1) to 10) is loaded;
About.

  By using the ink composition of the present invention, it was possible to provide a recorded image with significantly improved light resistance without impairing the excellent sharpness of the xanthene dye.

The present invention will be described in detail.
The ink composition of the present invention is a water-based ink composition and is suitable as a magenta ink, particularly as a magenta ink used for inkjet recording.

The xanthene dye contained in the ink composition of the present invention will be described.
The xanthene dye generally means a dye having a structure represented by the following formula (5), as described in, for example, Sadaharu Abeda et al.

Among the xanthene dyes, a dye represented by the following formula (2) is preferable.

In formula (2),
R ^{101 to} R ¹⁰⁴ each independently represents a hydrogen atom or a substituent,
R ¹⁰⁵ represents a sulfo group, a carboxy group, or a C1-C10 alkoxycarbonyl group,
R ¹⁰⁶ represents a hydrogen atom; or a substituent,
R ¹⁰⁷ and R ¹⁰⁸ each independently represent a hydrogen atom or a substituent,
R ^109- represents a counter anion.
However, when the dye represented by the formula (2) forms a salt in the molecule, ^R109- does not exist.

The dye represented by the formula (2) has isomers having different cation positions, for example, as represented by the following formula (6) or formula (7). In the present specification, the “xanthene dye” is meant to include all such isomers. In the following formula (6) or formula (7), R ^{101 to} R ¹⁰⁸ and R ^109- represent the same meaning as in formula (2).

Among the xanthene dyes represented by the formula (2), a dye represented by the formula (1) is preferable.

In the formula (1), examples of the C1-C10 alkyl group in R ^{1 to} R ⁴ include linear or branched ones. The range of carbon number is usually C1-C10, preferably C1-C8, more preferably C1-C6, and still more preferably C1-C4.
Specific examples thereof include, for example, straight chain such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl and n-decyl; isopropyl, isobutyl, sec- Branched chain such as butyl, tert-butyl, isopentyl, tert-pentyl, 2-ethylhexyl; and the like.
Among specific examples, methyl, ethyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl are preferable, methyl and ethyl are more preferable, and ethyl is particularly preferable.

As the C1-C10 alkyl group having a group selected from the group consisting of a hydroxy group, a carboxy group, and a sulfo group as a substituent in R ^{1 to} R ⁴ , the above-mentioned “C1-C10 alkyl group in R ^{1 to} R ⁴ ”. In which any carbon atom in these groups has these groups. The range of carbon number is usually C1-C10, preferably C1-C8, more preferably C2-C6, and still more preferably C2-C4. The number of the substituents is usually 1 or 2, and preferably 1. The position of the substituent is not particularly limited, but when the substituent is a hydroxy group, it is preferable that the hydroxy group and the nitrogen atom are not substituted with the same carbon atom.
Specific examples include those having a hydroxy group such as 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 6-hydroxyhexyl, 3-hydroxyoctyl; carboxymethyl, 2-carboxyethyl, 3-carboxypropyl , 6-carboxyhexyl, 8-carboxyoctyl and the like having a carboxy group; 2-sulfoethyl, 3-sulfopropyl, 4-sulfobutyl and the like having a sulfo group;
Preferable specific examples include 2-hydroxyethyl, 2-carboxyethyl, and 2-sulfoethyl.

As a substituent in R ^{1 to} R ⁴ , a phenyl group having a group selected from the group consisting of a hydroxy group, a carboxy group, a sulfo group, a sulfamoyl group, a C1-C4 alkyl group, a C1-C4 alkoxy group and a halogen atom Includes those having any of these groups as a substituent on any carbon atom of the phenyl group. The number of substituents is usually 1 to 5, preferably 1 to 4, more preferably 2 or 3.
As a C1-C4 alkyl group as a substituent, a linear or branched thing is mentioned, A linear thing is preferable. Specific examples thereof include linear ones such as methyl, ethyl, n-propyl and n-butyl; branched ones such as isopropyl, isobutyl, sec-butyl and tert-butyl.
As a C1-C4 alkoxy group as a substituent, a linear or branched thing is mentioned, A linear thing is preferable. Specific examples thereof include linear ones such as methoxy, ethoxy, n-propoxy and n-butoxy; branched ones such as isopropoxy, isobutoxy, sec-butoxy and tert-butoxy.
Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Among these, a fluorine atom, a chlorine atom, and a bromine atom are preferable. More preferred are a fluorine atom and a chlorine atom, and still more preferred are a chlorine atom.
Although the substitution position on the phenyl group of the above group is not particularly limited, the bonding position with the nitrogen atom in formula (1) is defined as the 1st position,
When the number of substituents is 3, the 2-position, 3-position and 6-position; or the 2-position, 4-position and 6-position;
When the number of substituents is 2, 2 and 3 positions; 2 and 4 positions; 2 and 5 positions; 2 and 6 positions; 3 and 4 positions; 3 and 5 positions;
When the number of substituents is 2, it is more preferable to substitute at the 2-position and the 6-position.
Specific examples include those having a hydroxy group such as 2-hydroxyphenyl, 3-hydroxyphenyl, 4-hydroxyphenyl; 2-carboxyphenyl, 3-carboxyphenyl, 4-carboxyphenyl, 2,5-dicarboxyphenyl, Those having a carboxy group such as 2,6-dicarboxyphenyl and 3,5-dicarboxyphenyl; 2-sulfophenyl, 3-sulfophenyl, 4-sulfophenyl, 2,5-disulfophenyl, 2,6- Those having a sulfo group such as disulfophenyl and 2,4-disulfophenyl; Those having a sulfamoyl group such as 2-sulfamoylphenyl, 3-sulfamoylphenyl and 4-sulfamoylphenyl; 2-methyl Phenyl, 3-ethylphenyl, 4-methylphenyl, 2,5-diethylpheny Having a C1-C4 alkyl group such as 2,6-dimethylphenyl, 2,4-dimethylphenyl, 2,4,6-trimethylphenyl; 2-methoxyphenyl, 3-ethoxyphenyl, 4-methoxyphenyl, 2 Having a C1-C4 alkoxy group such as 1,5-diethoxyphenyl; having a halogen atom such as 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl, 3-bromophenyl, 3-fluorophenyl; 3-methyl-4 -What has 2 or more types of groups selected from said groups, such as sulfophenyl and 2, 6- dimethylsulfophenyl; etc. are mentioned.
Of these, 2-carboxyphenyl, 2,6-dicarboxyphenyl, 2-sulfophenyl, 2-methylphenyl, 2,6-dimethylphenyl, and 2,6-dimethylsulfophenyl are preferred, and 2,6 -Dimethylphenyl and 2,6-dimethylsulfophenyl are particularly preferred.

Among the above, preferable R ¹ to R ⁴ are each independently a hydrogen atom; a C1-C10 alkyl group; a phenyl group having a group selected from the group consisting of a sulfo group and a C1-C4 alkyl group as a substituent. Is preferred.

As a preferable combination of R ^{1 to} R ⁴ , R ¹ is a phenyl group having a group selected from the group consisting of a sulfo group and a C1-C4 alkyl group as a substituent, R ² is a hydrogen atom, R ³ is Examples of the substituent include a phenyl group having a C1-C4 alkyl group and a combination in which R ⁴ is a hydrogen atom; or a combination in which all of R ^{1 to} R ⁴ are C1-C10 alkyl groups.

In formula (1), examples of the C1-C4 alkoxycarbonyl group for R ⁵ include linear or branched ones, and linear ones are preferred. Specific examples thereof include linear ones such as methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl and n-butoxycarbonyl; branched ones such as isopropoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl and tert-butoxycarbonyl; Is mentioned.

Among the above, R ⁵ is particularly preferably a sulfo group.

In formula (1), examples of the C1-C10 alkyl group for R ⁶ include the same ones as described in the above-mentioned “C1-C10 alkyl group for R ^{1 to} R ⁴ ”, including preferable ones.

As the substituent in R ⁶ , the C1-C10 alkyl group having a group selected from the group consisting of a hydroxy group, a carboxy group and a sulfo group includes the above-mentioned “hydroxy group as substituent in R ¹ to R ⁴ ,” The same thing is included including what is described in "the group C1-C10 alkyl group selected from the group which consists of a carboxy group and a sulfo group", a preferable thing, etc.

Examples of the halogen atom for R ⁶ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Among these, a fluorine atom, a chlorine atom, and a bromine atom are preferable. More preferred are a fluorine atom and a chlorine atom, and still more preferred are a chlorine atom.

Among the above, preferable R ⁶ includes a hydrogen atom, a C1-C10 alkyl group, a sulfo group, a carboxy group, and a halogen atom, and particularly preferably a hydrogen atom or a sulfo group.

In formula (1), examples of the C1-C10 alkyl group in R ⁷ and R ⁸ include the same ones as described in the above-mentioned “C1-C10 alkyl group in R ^{1 to} R ⁴ ”, including preferable ones. It is done.

Among the above, R ⁷ and R ⁸ are particularly preferably a hydrogen atom.

In the formula (1), R ⁹⁻ means a counter anion for the charge of the cation in the xanthene dye (that is, the “+” charge described in the formula (1)). When a strongly acidic group such as a sulfo group is present in the xanthene dye, a salt can be formed in the dye molecule, so that a counter anion represented by R ^9- is not required. For this reason, when the dye represented by formula (1) forms a salt in the molecule, R ⁹⁻ does not exist.

Examples of the halogen anion for R ^9- include fluoride, chloride, bromide, iodide and the like. Among these, chloride (Cl ⁻ ) is particularly preferable.

In R ^9- , the hydroxide, acetate anion, tetrafluoroborosan anion, hexafluorophosphate anion, sulfate anion, and toluenesulfonate anion are respectively “OH ⁻ ”, “CH ₃ COO ⁻ ”, and “BF ₄ ⁻ ”. , “PF ₆ ⁻ ”, “HSO ₄ ⁻ ”, and “CH ₃ C ₆ H ₄ SO ₃ ⁻ ”. Among these, for the toluenesulfonate anion, there are isomers in which the substitution position of the methyl group on the benzene ring is ortho, meta, or para with respect to the substitution position of the sulfonate anion. Including the body.

Among the above, R ⁹⁻ is preferably a halogen anion.
Further, as the dye represented by the formula (1), a dye that does not exist, that is, a dye that forms a salt in the molecule is more preferable than that in which R ⁹⁻ is present.

Among the dyes described as R ^{1 to} R ⁸ and R ⁹⁻ in the formula (1), a combination of preferable dyes is more preferable, and a combination of more preferable dyes is more preferable. The same applies to combinations of more preferable ones and combinations of preferable ones and more preferable ones.

As particularly preferred dyes represented by the formula (1), C.I. I. Acid Red 289 and C.I. I. Acid Red 52 is exemplified. Among these, the former is particularly preferable in terms of sharpness, hue, and ozone resistance.
C. I. Acid Red 289 is No. 1 in Table 1 below. 8 and no. A mixture of 9 dyes (monosodium salt thereof); I. Similarly, Acid Red 52 is No. 7 (the monosodium salt thereof) is known.

Although the specific example of a xanthene dye is shown in following Table 1, the xanthene dye which can be used by this invention is not limited to these specific examples. For convenience, acidic functional groups such as carboxy groups and sulfo groups are described in the form of free acids.
In Table 1, No. 6 to No. Since the dye of ^{No. 9} forms a salt in the molecule, R ⁹⁻ does not exist. These dyes are generally considered to form a salt in the molecule when the sulfo group of R ⁵ becomes an anion in the form of “SO ₃ ⁻ ”.
The abbreviations used in Table 1 have the following meanings.
Et: ethyl.
DM-3S-Ph: 2,6-dimethyl-3-sulfophenyl.
DM-4S-Ph: 2,6-dimethyl-4-sulfophenyl.
H: A hydrogen atom.
DM-Ph: 2,6-dimethylphenyl.
Me: methyl.

The xanthene dye can be synthesized according to a known method (for example, the method described in Yutaka Hosoda, Gihodo Publishing "Theoretical Manufacturing Dye Chemistry" pages 373-375 and pages 788-791) or a known method. There are also many dyes available as commercial products.

The xanthene dye may form a salt in addition to a salt using a cation charge existing in the molecule.
For example, in Table 1 above, 4 and no. Since the dye shown in 5 has a carboxy group as R ⁵ , this group can be converted into a salt.
In Table 1, No. 6 and no. Since the dye shown in 7 has a sulfo group as R ⁶ , this group can be similarly converted into a salt.
Such salts include salts with inorganic or organic cations. Specific examples of the inorganic cation salt include ammonium (NH ₄ ⁺ ); alkali metals such as cations such as lithium, sodium and potassium; and the like. Examples of the organic cation include, but are not limited to, quaternary ammonium represented by the following formula (3).

In the formula (3), Z _{1 to} Z ₄ each independently represent a hydrogen atom, a C1-C4 alkyl group, a hydroxy C1-C4 alkyl group or a hydroxy C1-C4 alkoxy C1-C4 alkyl group, and Z _{1 to} Z ₄ At least one of is a group other than a hydrogen atom.

Here, examples of the alkyl group in Z _{1 to} Z ₄ include methyl, ethyl and the like; similarly, examples of the hydroxyalkyl group include hydroxymethyl, hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 4-hydroxy Butyl, 3-hydroxybutyl, 2-hydroxybutyl and the like; and examples of hydroxyalkoxyalkyl groups include hydroxyethoxymethyl, 2-hydroxyethoxyethyl, 3- (hydroxyethoxy) propyl, 3- (hydroxyethoxy) Examples include butyl and 2- (hydroxyethoxy) butyl.

Preferable examples of the salt include sodium, potassium, lithium, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine salt, and ammonium salt. Of these, particularly preferred are lithium, sodium, potassium and ammonium salts.
Any of these salts can be easily synthesized according to a known method or a similar method.

The divalent copper compound contained in at least one kind in the ink composition of the present invention will be described.
The divalent copper compound (hereinafter simply described as “copper compound” unless otherwise specified) has a maximum absorbance of a 0.1 mass% aqueous solution in the measurement of absorbance using a spectrophotometer. The copper compound is 0.2 or less in a wavelength range of 400 to 600 nm. The lower limit may be a copper compound having a maximum absorbance of 0 or less in the range of 400 to 600 nm, that is, less than the measurement limit of the measuring instrument.
The present invention aims to improve the light resistance without impairing the excellent sharpness and hue, which is one of the characteristics of xanthene dyes. Those that do not affect the hue as much as possible are preferred. For this reason, it is preferable that the copper compound to be used in combination has the smallest possible absorption of visible light, that is, the maximum absorbance in the visible light wavelength range. Further, in the wavelength range of 400 nm to 600 nm, which roughly matches the wavelength range of three primary colors used for full-color ink jet recording, that is, yellow to magenta to cyan, a particularly small copper compound having a maximum absorbance is preferable. A numerical value such that the maximum absorbance of a 0.1 mass% aqueous solution is usually 0.2 or less, preferably 0.1 or less. The lower limit may be equal to or lower than the measurement limit of a measuring device for maximum absorbance (usually an ultraviolet-visible spectrophotometer), that is, the maximum absorbance may be zero.
The maximum absorbance can be measured by measuring the normal absorption wavelength in the wavelength range of 400 nm to 800 nm under a temperature condition of 25 ° C. using an ultraviolet-visible spectrophotometer, and obtaining the measured value in the wavelength range of 400 nm to 600 nm. That's fine.
In the present specification, the value of maximum absorbance is obtained by rounding the second decimal place to one decimal place.

Examples of the copper compound include an inorganic copper compound or a salt thereof; a copper compound or a salt thereof having a C1-C4 alkylenediamine as a ligand; and a C2-C4 which may have a carboxy C1-C4 alkyl group as a substituent. Copper compound having an alkylenediamine as a ligand or a salt thereof; an amino acid having a total carbon number of 2-12 (preferably not having an aromatic ring such as benzene, more preferably not having an aromatic ring such as a benzene ring) And a copper compound having a total carbon number of 2-6) or a salt thereof as a ligand. In these, the maximum absorbance of a 0.1% by mass aqueous solution in the wavelength range of 400 nm to 600 nm is usually 0.2 or less. However, some of these copper compounds are also sparingly soluble in water, and the copper compound contained in the ink composition of the present invention has water solubility capable of preparing a 0.1% by mass aqueous solution. Those are preferred.
Specific examples of the copper compound include copper acetate, copper chloride, copper sulfate, copper nitrate, diammonium copper chloride, tetraammine copper sulfate, copper hydroxide and other inorganic copper compounds or salts thereof; bis (ethylenediamine) copper sulfate, Copper compounds or salts thereof having C1-C4 alkylenediamine as a ligand, such as bis (ethylenediamine) copper hydrochloride, tris (ethylenediamine) copper sulfate; bis (glycinato) copper, bis (L-alaninato) copper, bis (Β-Alaninato) copper compound having a total number of carbon atoms of 2-12 such as copper as a ligand or a salt thereof; N, N, N ′, N′-ethylenediaminetetraacetate copper, N, N, N ′ , N′-ethylenediaminebisacetobispropionate copper, N, N, N ′, N′-propylenediaminetetraacetatoquacopper as a substituent such as carboxy C1-C4 A good C2-C4 alkylenediamine have a alkyl group, a copper compound having as a ligand or a salt thereof; and the like.
In these, an inorganic copper compound or its salt; Or the copper compound or its salt which has C2-C4 alkylenediamine which may have a carboxy C1-C4 alkyl group as a substituent as a ligand is preferable.
Among specific examples, preferred are copper acetate, copper chloride, copper sulfate, copper hydroxide, tetraammine copper sulfate, bis (L-alaninate) copper, N, N, N ′, N′-ethylenediaminetetraacetate copper, Copper acetate, copper chloride, copper sulfate, copper hydroxide, N, N, N ′, N′-ethylenediaminetetraacetate copper are more preferable, and copper acetate, copper chloride, copper sulfate, N, N, N ′, N′— Particularly preferred is ethylenediaminetetraacetate copper.

There are many divalent copper compounds available as commercial products. Further, a copper compound having a C1-C4 alkylenediamine as a ligand or a salt thereof; a copper compound having a C2-C4 alkylenediamine which may have a carboxy C1-C4 alkyl group as a substituent or a salt thereof Etc. can also be synthesized by a known method. For example, in accordance with the methods described in Maruzen Publishing "New Experimental Chemistry Course" 1st edition, Volume 8, 1520 to 1547, and "New Experimental Chemistry Course" 4th edition, Volumes 177-181 and 238-273. Can be synthesized.

In addition to xanthene dyes and divalent copper compounds, the ink composition of the present invention includes the specific group described in the above 8), that is, “C1-C10 alkyl carboxylic acid; C1-C10 alkyl carboxylic acid having a hydroxy group”. C1-C10 alkyl dicarboxylic acid; iminodiacetic acid; N-hydroxyiminodiacetic acid; C1-C10 polyhydric alcohol in which an oxygen atom may be inserted into the C1-C10 moiety; C1-C10 polyhydric alcohol C1-C4 alkyl ether; A crown ether; a saccharide; an ammonia; a C1-C10 alkylamine; a C1-C10 alkylamine having a substituent selected from the group consisting of a hydroxy group, a carboxy group and a sulfo group; a C1-C10 alkylenediamine; 2-cyclohexylenediamine; C1-C having a carboxy group 0 alkylenediamine; at least one compound selected from the group consisting of “C1-C10 alkylenediamines in which the nitrogen atom is substituted with a carboxy C1-C4 alkyl group” (hereinafter referred to as “specific group”) It is preferable to contain.
This “specific group” of compounds is considered to be involved in the stabilization and easy solubilization of the copper compound in the ink composition, and preferably contains at least one kind, and a plurality of kinds may be used in combination. This “specific group” of compounds may optionally form a complex with the copper compound.

Examples of the C1-C10 alkyl carboxylic acid in the “specific group” include linear or branched alkyl moieties, and linear ones are preferred. The range of carbon number is usually C1-C10, preferably C1-C4. Specific examples thereof include linear alkyl moieties such as acetic acid, propionic acid, n-butanoic acid, n-pentanoic acid, n-hexanoic acid, n-heptanoic acid, n-octanoic acid and n-decanoic acid; And branched chain ones such as isobutyric acid, isovaleric acid, and tert-butylcarboxylic acid. Among these, preferred are acetic acid, propionic acid, n-butanoic acid and n-pentanoic acid, and acetic acid is particularly preferred.

The C1-C10 alkyl carboxylic acid having a hydroxy group in the “specific group” has a hydroxy group at any carbon atom of the alkyl moiety in the “C1-C10 alkyl carboxylic acid in the“ specific group ”. Is mentioned. The number of the hydroxy groups is usually 1 to 4, preferably 1 to 3, more preferably 1 or 2, and still more preferably 1. The substitution position of the hydroxy group is not particularly limited.
Specific examples include 2-hydroxypropionic acid, 2-hydroxybutanoic acid, 3-hydroxybutanoic acid, 6-hydroxyhexanoic acid, 3-hydroxyoctanoic acid; and the like.
Preferable specific examples include 2-hydroxypropionic acid.

Examples of the C1-C10 alkyl dicarboxylic acid in the “specific group” include linear or branched ones, and linear ones are preferred. The range of carbon number is usually C1-C10, preferably C1-C4. Specific examples thereof include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, 1,6-hexanedicarboxylic acid, 1,7-heptanedicarboxylic acid, 1,9-nonanedicarboxylic acid, and the like. Malonic acid and succinic acid are preferred.

Examples of the C1-C10 polyhydric alcohol in which an oxygen atom may be inserted into the C1-C10 moiety in the “specific group” include diols such as ethylene glycol, propylene glycol, tetramethylene glycol, hexamethylene glycol; diethylene diglycol , Polyalkylene glycols in which an oxygen atom is inserted into the C1-C10 portion, such as triethylene diglycol, tetraethylene diglycol, dipropylene diglycol; triols such as glycerin and hexane-1,2,6-triol; Is mentioned. Among these, ethylene glycol, propylene glycol, diethylene diglycol, triethylene diglycol, and glycerin are preferable.

In the “specific group”, the C1-C10 polyhydric alcohol C1-C4 alkyl ether in which an oxygen atom may be inserted into the C1-C10 moiety includes ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether , Diethylene glycol monoethyl ether, diethylene glycol monobutyl ether (butyl carbitol), triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, and the like. Among these, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, and triethylene glycol monomethyl ether are preferable.

Examples of the crown ether in the “specific group” include 12-crown-4; 15-crown-5; 18-crown-6; 24-crown-8;

The saccharides in the “specific group” include monosaccharides and oligosaccharides such as glucose, lactose, maltose, saccharose, galactose, and fructose; sugar acids such as ascorbic acid, gluconic acid, glucoheptonic acid, and glucosamic acid; xylitol, ribitol, Sugar alcohols such as inositol, maltitol, sorbitol, iditol, and arabitol;

Examples of the C1-C10 alkylamine in the “specific group” include those in which the alkyl moiety is linear or branched. The range of carbon number is usually C1-C10, preferably C1-C8, more preferably C1-C4. Specific examples thereof include linear alkyl moieties such as methylamine, ethylamine, n-propylamine, n-butylamine, n-pentylamine, n-hexylamine, n-octylamine and n-decanylamine; isopropylamine , Alkyl groups such as isobutylamine, sec-butylamine, tert-butylamine, isopentylamine, tert-pentylamine and 2-ethylhexylamine are branched; Preferable specific examples include isopropylamine, butylamine, and isobutylamine.

As the C1-C10 alkylamine having a group selected from the group consisting of a hydroxy group, a carboxy group, and a sulfo group as a substituent in the “specific group”, any carbon atom in the C1-C10 alkyl group may be used. What has these groups as a substituent is mentioned. The number of the substituent and the position of the substituent are not particularly limited. The range of carbon number is usually C1-C10, preferably C1-C8, more preferably C1-C4.
Specific examples include those having a hydroxy group such as 2-hydroxyethylamine, 2-hydroxypropylamine, 3-hydroxypropylamine, 6-hydroxyhexylamine, 3-hydroxyoctylamine; carboxymethylamine, 2-carboxyethylamine, One or two carboxy groups such as 3-carboxypropylamine, 1-carboxyisobutylamine, 6-carboxyhexylamine, 8-carboxyoctylamine, 1,2-dicarboxyethylamine, 1,3-dicarboxypropylamine Those having a sulfo group such as 2-sulfoethylamine, 3-sulfopropylamine, 4-sulfobutylamine; 1-carboxy-2-hydroxyethylamine, 1-carboxy-2-hydroxypropylamine, etc. Type groups (preferably one hydroxy group and a carboxy group) as having; and the like are.
Among these, 2-hydroxyethylamine, carboxymethylamine, 2-carboxyethylamine, 1-carboxyethylamine, 3-carboxypropylamine, 4-carboxybutylamine, 1,2-dicarboxyethylamine, 1,3-dicarboxypropyl Preferred are amines.
In addition, it has one or two carboxy groups such as carboxymethylamine, 2-carboxyethylamine, 3-carboxypropylamine, 4-carboxybutylamine, 1,2-dicarboxyethylamine, 1,3-dicarboxypropylamine, etc. C1-C10 alkylamines are particularly preferred among these because they have a high stabilizing effect on divalent copper compounds in the ink composition.

Examples of the C1-C10 alkylenediamine in the “specific group” include those having a carbon number range of usually C1-C10, preferably C1-C8, more preferably C1-C6, and further preferably C1-C4. It is done. Specific examples thereof include alkylene chains such as ethylenediamine, 1,3-propylenediamine, 1,4-butylenediamine, 1,5-pentylenediamine, 1,6-hexylenediamine, 1,8-octylenediamine, and the like. Having amines at both ends thereof; 1,2-propylenediamine, 1,2-butylenediamine, 2,3-butylenediamine, 1,2-hexylenediamine, 3,4-hexylenediamine, 2,5- And those having an amine at an arbitrary position of an alkylene chain such as dimethyl-3,4-hexylenediamine or those having a branched alkylene chain. Preferable specific examples include ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, 1,6-hexylenediamine, 1,2-propylenediamine, 1,2-butylenediamine, 2,3-butylenediamine. 1,2-hexylenediamine, 3,4-hexylenediamine, and ethylenediamine and 1,2-propylenediamine are particularly preferable.

Examples of the C1-C10 alkylene diamine having a carboxy group in the “specific group” include those having a carboxy group as a substituent on any carbon atom in the “C1-C10 alkylene diamine in the“ specific group ”. It is done. The number of the substituent and the position of the substituent are not particularly limited. Specific examples thereof include 1-carboxyethylenediamine, 1-carboxypropylenediamine, 1-carboxybutylenediamine, 1-carboxypentylenediamine, and the like. Preferred specific examples are 1-carboxyethylenediamine and 1-carboxypropylenediamine.

The C1-C10 alkylenediamine in which the nitrogen atom in the “specific group” is substituted with a carboxy C1-C4 alkyl group is one in which the nitrogen atom of the diamine is substituted with one or two carboxy C1-C4 alkyl groups, respectively. Is mentioned. The number of substituents and the position of the substituents are not particularly limited, but N and N ′ nitrogen atoms are each substituted with two carboxy C1-C4 alkyl groups, that is, N, N, N ', N'-C1-C10 alkylene diamine tetra C1-C4 alkyl carboxylic acid is preferred. As for the range of carbon number, the C1-C10 alkylene moiety is usually C1-C10, preferably C2-C6, more preferably C2-C4, more preferably C2-C3; and the C1-C4 alkyl moiety is usually C1. -C4, preferably C1-C3, more preferably in the range of C1-C2.
The carboxy C1-C4 alkyl group, which is a substituent of the nitrogen atom, need not be the same on one nitrogen atom or between two nitrogen atoms, but is preferably the same.
Specific examples thereof include N, N′-ethylenediaminediacetic acid, N, N, N ′, N′-ethylenediaminetetraacetic acid, ethylenediamine-N, N′-diacetic acid-N, N′-dipropionic acid, N , N, N ′, N′-propylenediaminetetraacetic acid, N, N, N ′, N′-ethylenediaminetetrapropionic acid, N, N, N ′, N′-tetramethylenediaminetetraacetic acid, N, N, N ', N'-hexamethylenediaminetetraacetic acid, and the like. Preferred examples include N, N, N ′, N′-ethylenediaminetetraacetic acid and ethylenediamine-N, N′-diacetic acid-N, N′-dipropionic acid, with N, N being particularly preferred. , N ′, N′-ethylenediaminetetraacetic acid.

Among the above, preferable “specific group” compounds include C1-C10 carboxylic acid; C1-C10 alkyldicarboxylic acid; ammonia; a group selected from the group consisting of a hydroxy group, a carboxy group, and a sulfo group as a substituent. A C1-C10 alkylene diamine; a C1-C10 alkylene diamine having a carboxy group; a C1-C10 alkylene diamine in which the nitrogen atom is substituted with a carboxy C1-C4 alkyl group;
More preferred are C1-C10 carboxylic acid; ammonia; C1-C10 alkylene diamine; C1-C10 alkylamine having a group selected from the group consisting of a hydroxy group, a carboxy group and a sulfo group as a substituent; nitrogen atom Is a C1-C10 alkylenediamine substituted with a carboxy C1-C4 alkyl group.
Among these, C1-C10 alkylenediamine in which the nitrogen atom is substituted with a carboxy C1-C4 alkyl group is particularly preferable.

The “specific group” of compounds may form a salt by utilizing an acidic functional group such as a carboxy group or a sulfo group present in the molecule; or a basic functional group such as an amine.

Among these, when forming a salt using an acidic functional group, the salt is the same as the salt described in the salt with an inorganic or organic cation in the xanthene dye, including preferable ones. Is mentioned.

In addition, when a salt is formed using a basic functional group such as an amine, the salt includes hydrochloride, hydrobromide, sulfate, nitrate, perchlorate, tetrafluoroborate, hexa Fluorophosphate, toluenesulfonate, methanesulfonate, acetate, propionate, C1-C10 alkylcarboxylate and the like can be mentioned.

The content of the xanthene dye contained in the ink composition of the present invention is usually 0.5 to 20% by mass, preferably 1 to 10% by mass, more preferably 1.% by mass relative to the total mass of the ink composition. It is good to contain 5-6 mass%, More preferably, 3-6 mass%.
Moreover, content of the copper compound contained in an ink composition is 0.01-10 mass% normally in conversion amount of the atomic weight of copper in a copper compound with respect to the total mass of an ink composition, Preferably it is 0. 0.05 to 5% by mass, more preferably 0.07 to 3% by mass, still more preferably 0.1 to 1% by mass, and particularly preferably 0.1 to 0.5% by mass.
Here, the “converted amount of the atomic weight of copper in the copper compound” has the following meaning. That is, taking copper chloride dihydrate (CuCl ₂ .2H ₂ O) as an example, its molecular weight is 170.48. Here, the atomic weight of copper is 63.546. For this reason, the conversion amount of the atomic weight of copper in 1 mass part of copper chloride dihydrate is calculated | required by calculating "1 mass part x (63.546 / 170.48)".
The content of the “specific group” compound contained in the ink composition is usually 0.2 to 30% by mass, preferably 0.5 to 20% by mass, more preferably based on the total mass of the ink composition. Is preferably contained in an amount of 0.5 to 15% by mass, more preferably 1 to 10% by mass.
However, many of the compounds of the “specific group” are the same as the water-soluble organic solvent, ink preparation agent, pH adjuster and chelating reagent described later. For this reason, the range of the total mass of the “specific group” compounds describes the range when contained as the “specific group”. When used as a water-soluble organic solvent or an ink preparation agent to be described later, it may be added to the ink composition of the present invention according to the range of the content thereof.
In addition, about the range of the mass% in each said content, about the numerical value which set the upper and lower limits of each range, if necessary, a numerical value one digit smaller (for example, the setting value of the range of one decimal place) The second digit) is rounded off to determine whether or not the range is met.
As will be described later, for the purpose of fine-tuning the magenta hue and the like, the ink composition of the present invention may further contain a known dye as long as the effect obtained by the present invention is not impaired. As the coloring matter contained in the ink composition, it is preferable that substantially all of the coloring matter is a xanthene dye for the purpose of not impairing the clarity and hue of the xanthene dye.

The ink composition of the present invention can be used for dyeing natural and synthetic fiber materials or blended products, ink for writing, and the like, but is particularly suitable for inkjet recording.

The ink composition of the present invention is prepared using water as a medium. If necessary, the ink composition may contain a water-soluble organic solvent and an ink preparation agent as long as the effects of the present invention are not impaired. The water-soluble organic solvent is used in anticipation of effects such as dissolution of dye, prevention of drying (maintaining wet state), adjustment of viscosity, promotion of penetration, adjustment of surface tension, defoaming, and the like. It is preferable to contain the product. Other ink preparation agents include, for example, antiseptic / antifungal agents, pH adjusting agents, chelating reagents, rust preventing agents, UV absorbers, viscosity adjusting agents, dye dissolving agents, antifading agents, surface tension adjusting agents, antifoaming agents. And the like, and known additives.
The content of the water-soluble organic solvent is 0 to 60% by mass, preferably 5 to 50% by mass, based on the total mass of the ink, and the ink preparation agent is similarly 0 to 20% by mass, preferably 0 to 15% by mass. Used. The remainder other than the above is water.

Examples of the water-soluble organic solvent include C1-C4 alkanols (alcohols) such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol and tert-butanol; N, N-dimethylformamide Or amides such as N, N-dimethylacetamide; 2-pyrrolidone, N-methyl-2-pyrrolidone, hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidin-2-one or 1,3-dimethylhexahydro Heterocyclic ketones such as pyrimido-2-one; ketones or ketoalcohols such as acetone, methyl ethyl ketone, 2-methyl-2-hydroxypentan-4-one; cyclic ethers such as tetrahydrofuran, dioxane; ethylene glycol, 1,2 -Or 1,3-propylene rubber C2- such as coal, 1,2- or 1,4-butylene glycol, 1,6-hexylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, or thiodiglycol Mono, oligo or polyalkylene glycols or thioglycols having C6 alkylene units; polyols (preferably triols) such as glycerin, hexane-1,2,6-triol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether , Diethylene glycol monoethyl ether, diethylene glycol monobutyl ether (butyl carbitol), triethylene glycol Bruno methyl ether, C1-C4 monoalkyl ether of polyhydric alcohol such as triethylene glycol monoethyl ether; .gamma.-butyrolactone; or dimethyl sulfoxide and the like.

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

Examples of antiseptic / antifungal agents include organic sulfur, organic nitrogen sulfur, organic halogen, haloaryl sulfone, iodopropargyl, N-haloalkylthio, benzothiazole, nitrile, pyridine, 8- Oxyquinoline, isothiazoline, dithiol, pyridine oxide, nitropropane, organotin, phenol, quaternary ammonium salt, triazine, thiadiazine, anilide, adamantane, dithiocarbamate, brominated indanone And compounds such as benzyl bromacetate and inorganic salts.
An example of the organic halogen compound is sodium pentachlorophenol.
Examples of pyridine oxide compounds include sodium 2-pyridinethiol-1-oxide.
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.
Other antiseptic / antifungal agents include sodium sorbate, sodium acetate and sodium benzoate.
Other specific examples of the antiseptic / antifungal agent include, for example, trade names Proxel ^RTM GXL (S) and Proxel ^RTM XL-2 (S) manufactured by Arch Chemicals Japan Co., Ltd.

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

Examples of chelating reagents 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 ultraviolet absorber include benzophenone compounds, benzotriazole compounds, cinnamic acid compounds, triazine compounds, stilbene compounds, and the like, and compounds that emit fluorescence by absorbing ultraviolet rays typified by benzoxazole compounds. So-called optical brighteners can also be used.

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

Examples of the dye solubilizer include urea, ε-caprolactam, ethylene carbonate, and the like. It is preferred to use urea.

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

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

Examples of anionic surfactants include alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, N-acyl amino acids and salts thereof, N-acyl methyl taurate, alkyl sulfate polyoxyalkyl ethers Sulfate, alkyl sulfate polyoxyethylene alkyl ether phosphate, rosin acid soap, castor oil sulfate ester, lauryl alcohol sulfate ester, alkylphenol type phosphate ester, alkyl type phosphate ester, alkylaryl sulfonate, diethylsulfosuccinate Salt, diethyl hexyl sulphosuccinate, dioctyl sulphosuccinate and the like.

Examples of the cationic surfactant include 2-vinylpyridine derivatives and poly-4-vinylpyridine derivatives.

Amphoteric surfactants include lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine, and other imidazoline derivatives. Is mentioned.

Nonionic surfactants include ethers such as polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene alkyl ether; Ester systems such as polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, polyoxyethylene stearate; 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5-di Acetylene glycols such as chill-1-hexyne-3-ol (alcohol) based; As another example, for example, manufactured by Nissin Chemical Industry Co., Ltd., trade name Surfynol ^RTM 104, 82, 465, Olfine ^RTM STG; etc. Is mentioned.

As the antifoaming agent, a highly oxidized oil-based, glycerin fatty acid ester-based, fluorine-based, or silicone-based compound is used as necessary.

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

In order to produce the ink composition of the present invention, there is no particular limitation on the order of dissolving each component such as an additive. The water used for preparing the ink composition is preferably water with few impurities such as ion exchange water or distilled water.
The ink composition thus prepared may be free from impurities by performing microfiltration using a membrane filter or the like as necessary.
When the ink composition is used for inkjet recording, microfiltration is preferably performed. The pore diameter of the filter for performing microfiltration is usually 1 μm to 0.1 μm, preferably 0.8 μm to 0.1 μm.

The ink composition of the present invention is suitable for use in printing, copying, marking, writing, drawing, stamping, or recording (printing), particularly in inkjet recording. In addition, the ink composition of the present invention is less likely to precipitate a solid even when dried in the vicinity of the nozzles of an ink jet printer, and for this reason, the head is not easily blocked. Further, when the ink composition of the present invention is used for ink jet recording, a high-quality magenta-colored recording material having good resistance to oxidizing gases such as water, light, ozone, and friction is obtained. The light resistance is extremely good.

In order to provide a higher-definition inkjet recording image, two similar colors of ink having high and low dye concentrations may be used for inkjet recording as an ink set. In this case, a high dye density is called, for example, magenta ink, and a low dye density is called light magenta ink. In such a case, two types of ink compositions of the present invention having different dye concentrations may be prepared and used as an ink set. Further, the ink composition of the present invention may be used for only one of them.
In addition, the ink composition of the present invention can also be used for toning of other colors, such as black ink, or for the purpose of preparing red ink or blue (or violet) ink by mixing with yellow dye or cyan dye. .

In the ink jet recording method of the present invention, a container containing the ink composition of the present invention is loaded in a predetermined position of an ink jet printer, and droplets of the ink composition are ejected in accordance with a recording signal to form a recording material. This is a method of recording by adhering.
The ink jet recording method of the present invention uses, in combination with the ink composition of the present invention, yellow, cyan, and, if necessary, each ink such as green, blue (or violet), red, and black to produce a full color recorded image. It can also be reproduced. In this case, the ink of each color is contained in each container, and these containers may be used by being loaded into a predetermined position of the ink jet printer.
Examples of the ink jet printer include those using a piezo method using mechanical vibration; a bubble jet (registered trademark) method using bubbles generated by heating; and the like. The ink jet recording method of the present invention can be used by any method.

Examples of the recording material include information transmission sheets such as paper and film, fibers and cloth (cellulose, nylon, wool, etc.), leather, and a base material for a color filter. Among these, an information transmission sheet is preferable.

The information transmission sheet is not particularly limited, and plain paper as well as surface-treated sheets, specifically, paper, synthetic paper, films and other substrates provided with an ink receiving layer are used. be able to. Here, the ink receiving layer is, for example, a method of impregnating or coating the base material with a cationic polymer; or inorganic fine particles capable of absorbing a dye in an ink composition such as porous silica, alumina sol, or special ceramics. And a method of coating the surface of the substrate together with a hydrophilic polymer such as polyvinylpyrrolidone. Those provided with such an ink receiving layer are usually called ink jet exclusive paper, ink jet exclusive film, glossy paper, or glossy film. Examples of the commercially available product include Seiko Epson Corporation, trade name: Photographic Paper Crispia ^RTM (high gloss); Brother Industries, Ltd., trade name: Photographic Glossy Paper BP71G;
Plain paper means paper that is not particularly provided with an ink-receptive layer, and various papers are commercially available depending on the application. Examples of commercially available plain paper include Seiko Epson, double-sided fine plain paper; Canon, color plain paper; Hewlett Packard, Multipurpose Paper, All-in-one Printing Paper; and the like. In addition, plain paper copy (PPC) paper whose use is not particularly limited to ink jet recording is also plain paper.

The colored body of the present invention means a substance colored with the ink composition of the present invention. Although there is no restriction | limiting in particular in the material of a colored body, For example, the said recording material etc. are mentioned preferably. Examples of the coloring method include a dip dyeing method, a textile printing method, a printing method such as screen printing, and a method using ink jet recording. In these, the inkjet recording method is preferable, and the colored body colored with the inkjet recording method of this invention is especially preferable.

The ink composition of the present invention has very good storage stability without solid precipitation, change in physical properties, change in hue, etc. after long-term storage. A recorded matter obtained by using the ink composition of the present invention for ink jet recording has an ideal hue as a magenta hue without selecting a recording material (for example, paper, film, etc.), and a photographic color It is also possible to reproduce the image faithfully on paper.
Furthermore, the ink composition of the present invention has high color developability, and the sharpness, which is one of the characteristics of xanthene dyes, is extremely good. Also, even when recorded on a recording material coated with a porous white inorganic material, it is excellent in various fastness properties, that is, gas resistance such as water resistance, moisture resistance and ozone gas resistance, especially compared with conventional ones. The light resistance is greatly improved, and the long-term storage stability of recorded images is also excellent. For this reason, it is suitable for inkjet recording, which is one of the features that a recording medium is not selected. In addition, when the ink composition of the present invention is used for ink jet recording, solid deposition due to drying of the ink composition in the vicinity of the nozzle is very unlikely to occur, and the ejector (ink head) is not blocked.
Thus, the ink composition of the present invention is extremely useful as an ink for various inks, particularly for ink jet recording.

  Hereinafter, the present invention will be described more specifically with reference to examples. In the text, “parts” and “%” are based on mass unless otherwise specified.

[Measurement of maximum absorbance of divalent copper compound in wavelength range of 400 to 600 nm]
Using an ultraviolet-visible spectrophotometer, UV-2550 (manufactured by Shimadzu Corporation), the absorption wavelength was measured at 25 ° C. in the wavelength range of 400 nm to 800 nm. As a method for preparing the sample, 0.1 g of a copper compound was weighed and made into a 100 ml aqueous solution with ion-exchanged water in a 100 ml volumetric flask to obtain a 0.1% by mass aqueous solution of a divalent copper compound. The obtained aqueous solution was used for the measurement of the maximum absorbance.
The maximum absorbance in the wavelength range of 400 nm to 600 nm of the divalent copper compound used in each example, measured by this method, is shown in Table 2 below. The maximum absorbance is a value obtained by rounding off the second digit after the decimal point as described above, and the actual measurement value is shown in parentheses for reference. Moreover, as for the wavelength which showed the maximum absorbance in the said wavelength range, all the copper compounds were 600 nm.
Under the same conditions, C.I. I. An attempt was made to measure the maximum absorbance of Acid Red 289, but the absorbance was too high to be measured. Therefore, when a 0.001 mass% aqueous solution was prepared and the maximum absorbance in the wavelength range of 400 nm to 600 nm was measured as a reference value, the maximum absorbance was 1.28, and the wavelength indicating the maximum absorbance was It was 527 nm, which coincided with the maximum absorption wavelength of the dye.

The meanings of abbreviations and the like in Table 2 are as follows, and in the following specification, these abbreviations are used with the same meaning.
Cu-EDTA · 2Na: N, N, N ′, N′-ethylenediaminetetraacetate copper disodium (copper is divalent).
CuCl ₂ · 2H ₂ O: Copper (II) chloride dihydrate.
Cu (OAc) ₂ .1H ₂ O: acetic acid (II) copper monohydrate.
CuSO ₄ .5H ₂ O: sulfuric acid (II) copper pentahydrate.

As is clear from the results in Table 2, all of the divalent copper compounds used in each example had a maximum absorbance of 0.2 or less in the wavelength range of 400 nm to 600 nm.

(A) Preparation of ink By mixing each component at the composition ratio shown in Table 3 below, the ink compositions of Examples 1 to 6 of the present invention; and Comparative Examples 1 and 2 for comparison were prepared. I got each. The obtained ink composition was filtered through a 0.45 μm membrane filter to remove impurities and obtain a test ink. In preparing the ink, water was added so that the total amount would be 100 parts after adjusting with a 25% aqueous sodium hydroxide solution so that the pH of the ink composition would be approximately 8.0 to 10.0. The total amount of 25% sodium hydroxide aqueous solution used for adjusting the pH and the total amount of water added so as to be 100 parts in total is shown as “aq. NaOH” in Table 3 below. The “water” used for the preparation of the ink is ion-exchanged water.
The ink compositions of Comparative Examples 1 and 2 do not contain a copper compound, and correspond to the ink compositions of Examples 1 to 4 and Example 6 except that the same number of water as the copper compound was added. To do.
Moreover, the numerical value of each column in Table 3 represents the number of copies, and the symbol “-” represents that the component is not contained.

The meanings of the abbreviations in Table 3 are as follows. In the following specification, these abbreviations are used in the same meaning.
AR52: C.I. I. Acid Red 52.
AR289: C.I. I. Acid Red 289.
NMP: N-methyl-2-pyrrolidone.
IPA: isopropyl alcohol.
BuCt: Butyl carbitol.
Surfactant: Nissin Chemical Co., Ltd., trade name Surfinol ^RTM 104PG50.

In Table 3, “Cu (OAc) ₂ .1H ₂ O + Glu” means that an aqueous solution prepared by previously mixing copper acetate and glutamic acid was prepared and used. The preparation method of this aqueous solution is described below.

[Preparation of Cu (OAc) ₂ · 1H ₂ O + Glu aqueous solution]
To 7.36 parts of glutamic acid, 5.0 parts of copper acetate monohydrate and 20.0 parts of water are added, pH is adjusted to 7.0 by addition of 25% aqueous sodium hydroxide solution, and water is added to bring the total amount of the aqueous solution to 50. After setting to 0 part, it stirred at room temperature for 10 minutes and obtained aqueous solution.
The obtained aqueous solution was used for the preparation of the ink of Example 5 without any particular purification.

(B) Inkjet recording The following two types of recording materials (glossy paper), which are exclusive inkjet paper having an ink receiving layer containing a porous white inorganic substance, using an inkjet printer (trade name: Pixus ^RTM iP4500, manufactured by Canon Inc.) Inkjet recording was performed on 1 and glossy paper 2).

Glossy paper 1:
Product name: Photographic Paper Crispia ^RTM (high gloss), manufactured by Seiko Epson Corporation.
Glossy paper 2:
Product name: Photo Glossy Paper BP71G, manufactured by Brother Industries, Ltd.

During ink jet recording, an image pattern was prepared so that gradations of 100, 85, 70, 55, 40, and 25% were obtained, and a recorded matter was obtained. The obtained recorded matter was used as a test piece, and the following xenon light resistance test was performed. In the xenon light resistance test, the reflection density was measured for the 70% gradation portion of the recorded material on which ink jet recording was performed. The reflection density was measured using a colorimetric system (trade name: SpectroEye ^RTM , manufactured by X-right). Colorimetry was performed under the conditions of DIN, a viewing angle of 2 degrees, and a light source D65 as a density reference.
Various test methods for recorded images are described below.

[(C) Xenon light resistance test]
Each test piece was placed in a holder and irradiated with a xenon weatherometer XL75 (manufactured by Suga Test Instruments Co., Ltd.) at a temperature of 24 ° C., a humidity of 60% RH, and 100 klux illuminance for 48 hours. The reflection density of each test piece before and after the test was measured by the above colorimetry system, and the dye residual ratio was calculated by (reflection density after test / reflection density before test) × 100 (%). The results are shown in Table 2 below.

[(D) Clarity evaluation test]
The reflection density was measured for the 100% gradation portion of each test piece.
The sharpness (C *) was calculated from chromaticity (a *, b *) as C * = [(a *) ² + (b *) ² ] ^1/2 .
The results of the calculated C * values are shown in Table 4 below. In addition, the larger the C * value, the better the clarity.

As is clear from the results in Table 4, each Example containing a xanthene dye and a copper compound showed higher light resistance than each Comparative Example containing no copper compound. That is, Examples 1 to 5 containing AR289 as a xanthene dye showed a remarkably excellent pigment residual ratio compared to Comparative Example 1 containing the same dye. Moreover, Example 6 using AR52 as the xanthene dye showed a remarkably excellent pigment remaining rate as compared with Comparative Example 2 using the same dye.
In addition, in terms of clarity, it can be seen that each example and each comparative example are equivalent.
As a result, the inks of the respective examples containing both the xanthene dye and the copper compound were able to remarkably improve the light resistance without deteriorating the excellent sharpness of the xanthene dye that has been conventionally used. Was confirmed.

The ink composition of the present invention having significantly improved light resistance without impairing the sharpness, which is one of the characteristics of xanthene dyes, is extremely useful as various recording inks, particularly ink jet recording inks.

Claims (16)

An ink composition comprising at least one xanthene dye and at least one divalent copper compound, and
An ink composition having a maximum absorbance of a 0.1% by mass aqueous solution of the divalent copper compound in an absorbance measurement using a spectrophotometer of 0.2 or less in a wavelength range of 400 nm to 600 nm. The ink composition according to claim 1, wherein the xanthene dye is a dye represented by the following formula (1), an isomer at a cation position thereof, or a salt thereof.

[In Formula (1),
R ^{1 to} R ⁴ are each independently a hydrogen atom; a C1-C10 alkyl group; a C1-C10 alkyl group having a group selected from the group consisting of a hydroxy group, a carboxy group, and a sulfo group as a substituent; a phenyl group; A phenyl group having a group selected from the group consisting of a hydroxy group, a carboxy group, a sulfo group, a sulfamoyl group, a C1-C4 alkyl group, a C1-C4 alkoxy group and a halogen atom as a substituent;
R ⁵ represents a sulfo group, a carboxy group, or a C1-C4 alkoxycarbonyl group,
R ⁶ represents a hydrogen atom; a C1-C10 alkyl group; a C1-C10 alkyl group having a group selected from the group consisting of a hydroxy group, a carboxy group, and a sulfo group as a substituent; a sulfo group; a carboxy group; a sulfamoyl group; A group; or a halogen atom;
R ⁷ and R ⁸ each independently represent a hydrogen atom or a C1-C10 alkyl group,
R ⁹⁻ represents a halogen anion, hydroxide, acetate anion, tetrafluoroborate anion, hexafluorophosphate anion, sulfate anion, or toluenesulfonate anion.
However, when the dye represented by the formula (1) forms a salt in the molecule, R ⁹⁻ does not exist. ]. The ink composition according to claim 1 or 2, wherein the total mass of the xanthene dye contained in the ink composition is 0.5 to 20 mass% with respect to the total mass of the ink composition. 4. The content of the copper compound contained in the ink composition is 0.01 to 10% by mass in terms of the atomic weight of copper with respect to the total mass of the ink composition. 5. Item 4. The ink composition according to item. The divalent copper compound is copper acetate, copper chloride, copper sulfate, copper hydroxide, or N, N, N ′, N′-ethylenediaminetetraacetate copper or a salt thereof. The ink composition described in 1. In the dye represented by the formula (1),
R ¹ is a C1-C10 alkyl group; or a phenyl group having, as a substituent, a group selected from the group consisting of a sulfo group and a C1-C4 alkyl group;
R ² is a hydrogen atom or a C1-C10 alkyl group,
R ³ is a hydrogen atom; a C1-C10 alkyl group; or a phenyl group having a C1-C4 alkyl group as a substituent;
R ⁴ is a hydrogen atom or a C1-C10 alkyl group,
R ⁵ is a sulfo group, a carboxy group, or a C1-C4 alkoxycarbonyl group,
R ⁶ is a hydrogen atom or a sulfo group,
R ⁷ and R ⁸ are each independently a hydrogen atom or a C1-C10 alkyl group,
The ink composition according to any one of claims 2 to 5, wherein R ^9- is a halogen anion.
However, when the dye represented by the formula (1) forms a salt in the molecule, R ⁹⁻ does not exist. The xanthene dye is C.I. I. Acid Red 289, or C.I. I. The ink composition according to claim 1, which is Acid Red 52. C1-C10 alkyl carboxylic acid; C1-C10 alkyl carboxylic acid having a hydroxy group; C1-C10 alkyl dicarboxylic acid; iminodiacetic acid; N-hydroxyiminodiacetic acid; C1 in which an oxygen atom may be inserted in the C1-C10 moiety -C10 polyhydric alcohol; C1-C10 polyhydric alcohol C1-C4 alkyl ether in which an oxygen atom may be inserted in the C1-C10 moiety; crown ether; saccharide; ammonia; C1-C10 alkylamine; A C1-C10 alkylamine having a group selected from the group consisting of a group, a carboxy group and a sulfo group; a C1-C10 alkylenediamine; 1,2-cyclohexylenediamine; a C1-C10 alkylenediamine having a carboxy group; Carboxy C1-C4 A At least one compound further ink composition according to any one of claims 1 to 7 containing selected from the group consisting of; C1-C10 alkylene diamines substituted by kill group. The ink composition according to any one of claims 1 to 8, further comprising a water-soluble organic solvent. The ink composition according to claim 1, which is used for ink jet recording. An ink jet recording method for performing recording by ejecting droplets of the ink composition according to any one of claims 1 to 10 in accordance with a recording signal and attaching the droplets to a recording material. The inkjet recording method according to claim 11, wherein the recording material is an information transmission sheet. 13. The ink jet recording method according to claim 12, wherein the information transmission sheet is a plain paper or a sheet having an ink receiving layer containing a porous white inorganic substance. A colored body colored with the ink composition according to any one of claims 1 to 10. A colored body colored by the inkjet recording method according to claim 11. An ink jet printer loaded with a container containing the ink composition according to claim 1.