JP6506441B2 - Aqueous ink composition, ink jet recording method and colored body - Google Patents

Description

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

  Among various color recording methods, the inkjet recording method which is one of the representative methods generates small droplets of ink and adheres the same to various recording materials (paper, film, fabric, etc.) Recording method. This method is rapidly becoming popular in recent years because it is characterized by little noise generation because the recording head and the recording material do not come in direct contact with each other, and generation of noise is small and it is easy to miniaturize and speed up. It is expected.

  In recent years, with the development of inkjet technology, the printing speed in inkjet printing has been remarkably improved, and inkjet recording intended for use in commercial printing and offices has been proposed. In this case, the printing medium is generally plain paper having no ink receiving layer, and the hue, light fastness, and water resistance become the most important issues as compared with inkjet paper having an ink receiving layer, and the improvement is strong It is desired.

  Black ink is an important ink used for both monochrome and full color images. However, there are many technical difficulties in the development of dyes that are neutral in both the dark and light color gamuts, have high color density, and have excellent fastness, and considerable research and development has been carried out. Few have sufficient performance. Therefore, a black ink is generally prepared by mixing a plurality of various dyes. However, when an ink is prepared by mixing a plurality of dyes, problems such as the color changing depending on the recording material and the increase in discoloration particularly due to bleeding due to water tend to occur as compared with the case of preparing the ink with a single dye.

  For example, Patent Document 1 is proposed as a black ink in which a dye for color adjustment is further blended with a black dye, but it has not been possible to provide a product that sufficiently satisfies the market requirements.

  In addition, dyes represented by the following formula (1) described in the present specification are described in Patent Documents 2 to 5. However, these have not been able to fully satisfy the above problems in hue, light fastness and water fastness.

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

  An object of the present invention is to provide an aqueous ink composition exhibiting good storage stability, exhibiting a neutral gray to black hue, and having both excellent light fastness and water fastness of a recorded image.

  As a result of intensive studies to solve the problems as described above, the present inventors have found that the problems can be solved by the aqueous ink composition having the specific constitution described below, and completed the present invention.

That is, the present invention relates to the following 1) to 11).
1)
An aqueous ink composition comprising at least two colorants of colorant (I) and colorant (II), wherein the content of colorant (I) in the total mass of the aqueous ink composition is An aqueous ink composition comprising 2% by mass to 65% by mass with respect to the content of the colorant (II), and wherein the colorant (I) is a dye represented by the following formula (1) or a salt thereof .

(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, a substituent A group selected from the group consisting of an alkoxy group which may be substituted, 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 alkoxy group which may have a substituent, and an alkyl group Represents a group.
n represents 0 or 1; )
2)
The colorant (II) is C.I. I. The aqueous ink composition according to the above 1), which is Acid Black 2.
3)
3. The aqueous ink composition as described in 1) or 2) above, which further contains a compound represented by the following formula (2) as a pH adjuster.

(In formula (2), R ₈ , R ₉ and R ₁₀ each independently represent a group selected from the group consisting of a hydrogen atom, an alkyl group, a hydroxyalkyl group, and a hydroxyalkoxyalkyl group.)
4)
Any of the above 1) to 3), wherein the content of the colorant (I) in the total mass of the aqueous ink composition is 2% by mass or more and 50% by mass or less based on the content of the colorant (II) An aqueous ink composition according to any one of the preceding claims.
5)
In the above formula (1), in the above 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; Aqueous ink composition as described.
6)
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 sulfo The aqueous ink composition according to the above 1), which is a group, R ₇ is a hydrogen atom, and n is 1.
7)
C. I. The aqueous ink composition according to any one of the above 1) to 6), further comprising at least one colorant selected from Direct Orange.
8)
An ink jet recording method of performing recording by causing droplets of the aqueous ink composition according to any one of the above 1) to 7) to be discharged according to a recording signal and adhering to a recording material.
9)
9. The ink jet recording method according to 8), wherein the recording material is a sheet for information transmission.
10)
The colored body colored with the aqueous ink composition as described in any one of said 1)-7).
11)
An inkjet printer loaded with a container containing the aqueous ink composition according to any one of the above 1) to 7).

  According to the present invention, an aqueous ink composition having good storage stability, exhibiting a neutral gray to black hue, and having both excellent light fastness and water fastness of recorded images can be provided.

  The present invention will be described in detail below. In the present specification, including “Examples” and the like, “%” and “number of parts” are all described on a mass basis unless otherwise noted. Also, in the present specification, “CI” means “color index”.

The colorant (I) is a dye represented by the above formula (1), and 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, a nitro group A 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 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 which may have a substituent, and an alkyl group Represents a group to be

  Examples of the above-mentioned 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 it has a sulfo group. The C1-C4 alkoxy group which may be more preferable.

  Examples of the alkylsulfonyl group which may have a substituent include the alkylsulfonyl group which may have a hydroxy group, and a C1-C6 alkylsulfonyl group which may have a hydroxy group is preferable, and a hydroxy group is preferable. The C1-C4 alkyl sulfonyl group which may have 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.
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 And branched C1-C6 alkyl groups; cyclic C1-C6 alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl; and the like.

  Examples of the arylsulfamoylamino group which may have a substituent include the phenylsulfamoylamino group which may have a substituent, and phenylsulfamoylamino which may have an alkyl group. Groups are preferred. Examples of the alkyl group include the same as the above-mentioned alkyl group and preferable ones.

  Examples of the above-mentioned alkylcarbonylamino group include an alkylcarbonylamino group having the same alkyl group in the alkyl portion, including those preferred as the above alkyl group.

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

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, “one” is preferably R ₁ and “the other” is preferably R ₂ .

Among the above, as R ₅ , R ₆ and R ₇ ,
At least one is preferably a group other than a hydrogen atom,
More preferably, at least one is a group selected from a carboxy group, a sulfo group, and a nitro group,
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,
Particularly preferred is at least one hydrogen atom, and one of the remaining two is a sulfo group, and the other is a hydrogen atom or a nitro group.
Among these, “one” of “the remaining two” is preferably R ₆ , and “the other” is preferably R ₅ .

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 preferably a sulfo group and the other is a hydrogen atom.

In the above-mentioned formula (1), the following positions may be mentioned as the substitution positions of the nitro group, the R _{1 to} R ₇ and the — (SO ₃ H) n group whose substitution position is not specified.

[Substituting position of R ₁ , nitro group, and R ₂ ]
The substitution position of each group on the benzene ring which these substitutes makes the substitution position of the azo group couple | bonded with this benzene ring 1 position, and the substitution position of (a)-(c) is mentioned below.
(A) R ₁ is 2-position, nitro group is 4-position, R ₂ is 5-position.
(B) R ₁ is 4-position, nitro group is 2-position, R ₂ is 5-position.
(C) R ₁ is 2-position, nitro group is 5-position, R ₂ is 4-position.
Among these, preferably (a) or (b), more preferably (a).

[Replacement position of R ₃ and R ₄ ]
The substitution position of each group on the benzene ring to which they are substituted is 1-position of the azo group which is bonded to the benzene ring and which is bonded to the benzene ring having R _{5 to} R ₇ , R ₃ is 3-position , R ₄ is preferably substituted at the 6-position.

[Replacement position of R ₅ , R ₆ , and R ₇ ]
The substitution position of each group on the benzene ring which these substitutes makes the substitution position of the azo group couple | bonded with this benzene ring 1 position, and the substitution position of (a)-(c) is mentioned below.
(A) R ₅ is 2nd, R ₆ is 4th, and R ₇ is 5th.
(B) R ₅ is third, R ₆ is fifth, R ₇ is fourth.
(C) R ₅ is 2nd, R ₆ is 5th and R ₇ is 4th.
(D) R ₅ is 3rd, R ₆ is 4th, and R ₇ is 6th.
Among these, (a) is preferred.

[Substituted position of-(SO ₃ H) n group]
- (SO 3 _H) 1-position substitution position of the hydroxy _{group n} group is substituted to the naphthalene ring substituted as 3-position of the substitution position of the sulfo group substitution positions are identified, - the (SO 3 _{H) n} group Substitution at the 5-position is preferred.

For dye represented by the formula (1), the groups represented by R ₁ as R _7, and, nitro group and - each group substitution position is not specified, including "(SO 3 _{H) n} group" As for the substitution position of, a combination of preferable ones is more preferable, and a combination of more preferable ones is more preferable. The same applies to combinations of further preferable ones, combinations of preferable ones and more preferable ones, and the like.

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

  Among the dyes represented by the above formula (1), dyes represented by the following formula (22), formula (23) or formula (26) are particularly preferable, and among these, formula (22) is most preferable. These dyes are particularly effective in color development, light resistance, ozone resistance and water resistance.

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

The dye represented by the above formula (1) may be used as a salt.
As a salt of the dye represented by the said Formula (1), the salt formed with an inorganic or organic cation is mentioned. Among them, specific examples of inorganic salts include salts formed with cations of elements of Groups 1 or 2 of the periodic table of the elements, and ammonium salts. Among these, preferred inorganic salts are salts of lithium, sodium and potassium and ammonium salts.
Examples of the salt of an organic cation include, but not limited to, salts formed with a compound 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 can not be hydrogen atoms.

The alkyl group represented by Z ₁ , Z ₂ , Z ₃ and Z _{4 in} the formula (16) is preferably a C 1 -C 4 alkyl group, and specific examples thereof 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 and the like. Hydroxy-C 1 -C 4 alkoxy-C 1 -C 4 alkyl groups are mentioned, among which hydroxyethoxy-C 1 -C 4 alkyl groups are preferred. Particularly preferred are hydrogen atoms; methyl; hydroxy-C1-C4 alkyl groups such as hydroxymethyl, hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl, 4-hydroxybutyl, 3-hydroxybutyl, 2-hydroxybutyl and the like; Hydroxyethoxy-C1-C4 alkyl groups such as hydroxyethoxymethyl, 2-hydroxyethoxyethyl, 3-hydroxyethoxypropyl, 2-hydroxyethoxypropyl, 4-hydroxyethoxybutyl, 3-hydroxyethoxybutyl, 2-hydroxyethoxybutyl and the like It can be mentioned.

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.

  Preferred salts of organic cations are monoethanolamine salt, diethanolamine salt, triethanolamine salt, monoisopropanolamine salt, diisopropanolamine salt and triisopropanolamine salt.

The aqueous ink composition contains at least a colorant (II) in addition to the colorant (I). By containing the coloring agent (II), the black ink has a more neutral hue, and gives a recorded image excellent in light resistance and water resistance. As the colorant (II), black dyes are preferred, and in particular, C.I. I. Acid Black 2 is preferred.

C. I. Acid Black 2 is readily available. When using this for inkjet recording, it is preferable to remove the inorganic impurities generally mixed when obtained as a commercial product by a purification operation. Such purification procedures include, for example, a purification method using a reverse osmosis membrane; or a purification method such as stirring a dye precursor in a mixed solvent of alcohol and water such as methanol, filtering and drying, and the like. The inorganic impurities include, for example, chlorides of the elements of Group 1 and / or Group 2 of the periodic table (for example, sodium chloride and the like) and sulfides (for example, sodium sulfate and the like). When purification is performed, the total content of inorganic impurities in the total mass of the ink composition is preferably 100 ppm or less, and more preferably 50 ppm or less. The lower limit may be below the detection limit of the detection instrument, ie 0%.

In order to obtain the effects of the present invention by the above aqueous ink composition, the content of the colorant (II) and the content of the colorant (II) in the total mass of the ink composition are extremely important. . That is, the content of the colorant (I) is usually 2% to 65%, preferably 4% to 60%, more preferably 4% to 50%, based on the content of the colorant (II) is there. These contents are calculated by rounding off the first decimal place.
If this range is exceeded, the effects of the present invention can not be obtained or the effects are significantly reduced.

  The ink of the present invention may further contain a toning dye to achieve a desired hue. The dye for toning is preferably a reactive dye, an acid dye or a direct dye, and more preferably a direct dye, from the viewpoint of dyeability to a recording material.

  Specific examples of reactive dyes for toning include, for example, 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, etc .; I. Brown dyes such as Reactive Brown 2, 8, 9, 17, 33; C.I. I. And red dyes such as Reactive Red 3, 3: 1, 4, 13, 24, 29, 31, 31, 33, 125, 151, 206, 218, 226, 245, and the like.

  Specific examples of the acid dye for toning include, for example, C.I. I. Acid Yellow 1, 3, 11, 17, 18, 19, 23, 25, 36, 40, 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, 204, 207, 215, 219, 219, 219, 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, And red dyes such as 277, 289, 296, 299, 315, 318, 336, 337, 359, 361, 362, 364, 366, 399, 407, 415, and the like.

  Specific examples of direct dyes for toning include, for example, 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, 224, 225, 226, 227, 232, 233 And red dyes such as 240, 241, 242, 243 and 247; and the like.

  Of these 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. When one or more types of dyes selected from Acid Red 249 and 254 are contained, the print density obtained by the aqueous ink composition is more preferable because the color development is further enhanced. Among these, C.I. I. Orange dyes selected from Direct Orange are preferred.

The aqueous ink composition containing the pH adjusting agent represented by the above formula (2) can provide a stable ink which suppresses fluctuations in pH over a long period of time and does not cause changes in various physical properties. This effect is an effect which can not be obtained, for example, when using an inorganic compound such as a hydroxide (for example, sodium hydroxide) of the periodic table group 1 element of the element. Therefore, when providing the stable aqueous ink composition, it is preferable that the aqueous ink composition further contain a pH adjuster represented by Formula (2).
The pH after adjustment is usually 7 or more, preferably 7 to 12, and more preferably 7 to 10.

In the formula (2), as the alkyl group, hydroxyalkyl group and hydroxyalkoxyalkyl group for R ₈ , R ₉ and R ₁₀ , each of Z ₁ , Z ₂ , Z ₃ and Z ₄ in the above-mentioned formula (16) The same groups can be mentioned, including groups and preferred ones.
Among the above, as R ₈ , R ₉ and R ₁₀ , a hydrogen atom, an alkyl group or a hydroxyalkyl group is preferable. As a specific example thereof, for example, a hydrogen atom, a methyl group, an ethyl group, a hydroxymethyl group, hydroxyethyl And the like.

Specific examples of combinations of R ₈ , R ₉ and R ₁₀ of the compounds preferred as the formula (2) are shown in Table 5 below.

The water-based ink composition may appropriately contain a water-soluble organic solvent or an ink preparation agent, as needed, 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 aqueous ink composition is usually 30 mPa · s or less, preferably 20 mPa · s or less.

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

  The content of the water-soluble organic solvent is generally 0 to 50%, preferably 10 to 50%, and more preferably 25 to 50%, based on the total mass of the aqueous ink composition.

  Examples of the ink preparation agent include antiseptic and mildew proofing agents, pH adjusters, chelating agents, rust preventives, water soluble ultraviolet absorbers, water soluble polymer compounds, dye solubilizers, antioxidants, surfactants and the like. Be

  As the mildew proofing agent, sodium dehydroacetate, sodium benzoate, sodium pyridinethion-1-oxide, p-hydroxybenzoic acid ethyl ester, 1,2-benzisothiazolin-3-one and salts thereof and the like can be mentioned. When the antifungal agent is contained, it is preferably used in an amount of 0.02 to 1% based on the total weight of the aqueous ink composition.

  As the preservative, for example, organic sulfur type, organic nitrogen sulfur type, organic halogen type, haloallyl sulfone type, iodopropargyl type, N-haloalkylthio type, (double) nitrile type, pyridine type, 8-oxyquinoline type, Benzothiazole, isothiazoline, dithiol, pyridine oxido, nitropropane, organotin, phenol, quaternary ammonium salt, triazine, thiazine, anilide, adamantane, dithiocarbamate, brominated indanone And benzyl bromide acetate compounds, inorganic salt compounds and the like. Examples of organic halogen compounds include pentachlorophenol sodium. Examples of the pyridine oxidic compounds include 2-pyridinethiol-1-oxide sodium. Examples of inorganic salt compounds include 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 Be Other antiseptic and fungicides include sodium sorbate, sodium benzoate and the like.

As the pH adjusting agent, any substance can be used as long as it can control the pH of the ink, for example, in the range of 5 to 11 without adversely affecting the prepared ink. Examples thereof include 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 lithium carbonate. And carbonates of alkali metals such as sodium carbonate, sodium hydrogencarbonate and potassium carbonate, and inorganic bases such as potassium acetate, sodium silicate and disodium phosphate.
Among these, the pH adjuster represented by the above formula (2) is preferable.

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

  Examples of the rust inhibitor include acid sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropyl ammonium nitrite, pentaerythritol tetranitrate, dicyclohexyl ammonium nitrite and the like.

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

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

  As a dye solubilizer, for example, ε-caprolactam, ethylene carbonate, urea and the like can be mentioned, and of these, urea is preferable.

  As the antioxidant, for example, various organic and metal complex antifading agents can be used. Examples of the organic antifading agent include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, amines, chromans, alkoxyanilines, heterocycles, and the like.

As surfactant, well-known surfactant, such as anion, a cation, nonionic, is mentioned, for example.
As an anionic surfactant, alkyl sulfonates, alkyl carboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, N-acyl amino acids and salts thereof, N-acyl methyl taurine salts, alkyl sulfate poly Oxy alkyl ether sulfate, alkyl sulfate polyoxyethylene alkyl ether phosphate, rosin acid soap, castor oil sulfate ester salt, lauryl alcohol sulfate ester salt, alkylphenol type phosphate ester, alkyl type phosphate ester, alkyl allyl sulfone hydrochloric acid, diethyl sulfone Examples include borate, diethylhexylsulfosuccinate, dioctyl sulfoborate and the like.
Examples of cationic surfactants include 2-vinylpyridine derivatives and poly 4-vinylpyridine derivatives. Amphoteric surfactants such as lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyl dimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine and other imidazoline derivatives It can be mentioned.
As nonionic surfactants, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene alkyl ether, polyoxyallyl alkyl Ethers such as alkyl ethers, polyoxyethylene oleic acid, polyoxyethylene oleate ester, polyoxyethylene distearate ester, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquiolate, polyoxyethylene monooleate And esters such as polyoxyethylene stearate, 2,4,7,9-tetramethyl-5-decyne-4,7-di Acetylene glycol (alcohol) such as alcohol, 3,6-dimethyl-4-octin-3,6-diol, 3,5-dimethyl-1-hexyn-3ol (eg, Surfynol 104 manufactured by Nisshin Chemical Co., Ltd.) 105, 82, 420, 440, 465, etc., etc.).
Of these, Surfynol 420, 440, 465 is preferred.

In the production of the aqueous ink composition, the order in which the additives such as the colorant, the water-soluble organic solvent, and the ink regulator are dissolved is not particularly limited.
As water used for preparation of the ink composition, one having a small amount of the above-mentioned inorganic impurities such as ion exchanged water, distilled water and the like is preferable.
Also, if necessary, after preparation of the ink composition, microfiltration may be performed using a membrane filter or the like to remove contaminants in the ink composition. In particular, when the ink composition is used for inkjet recording, it is preferable to perform precision filtration. 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 above aqueous ink composition can be used in various fields. As an example, it can be used for writing, aqueous printing, information recording, etc., and it is particularly preferable to use it for inkjet recording.

  When the ink jet recording is performed, 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 equipped, According to the objective, it can select suitably. For example, a charge control method that ejects ink using electrostatic attraction; a drop-on-demand method (pressure pulse method) that uses the vibration pressure of a piezo element; an electric beam is changed to an acoustic beam and the ink is irradiated Acoustic ink jet system which ejects ink using pressure; thermal ink which forms bubbles and heats ink to form bubbles, and uses known ink jet recording system such as bubble jet (registered trademark) system; be able to. In the above-mentioned ink jet recording method, a method of ejecting many inks with small content of colorant called photo ink in small volume; using a plurality of inks having substantially the same hue but different content of colorant Also included are methods for improving image quality; and methods for using color ink and colorless and transparent ink in combination.

The inkjet recording method is a method of performing recording by causing droplets of the aqueous ink composition to be discharged in accordance with a recording signal and adhering the recording material.
The above-mentioned aqueous ink composition is used as a black ink, and combined with each ink composition such as magenta, cyan, yellow, if necessary, green, blue (or violet) and red (or orange) to obtain a full color It is also possible to obtain a recorded image of At this time, the ink composition of each color is injected into the respective container, and the container is loaded at a predetermined position of the ink jet printer and used for the ink jet recording as the container containing the aqueous ink composition. it can.

The colored body means a substance colored with the aqueous ink composition, preferably a substance colored by the ink jet 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, for example, sheets for transmitting information such as paper and film; fibers and cloth (cellulose, nylon, wool etc); leather; base materials for color filters;
As a sheet for information transmission, both surface-treated sheets, specifically, sheets provided with an ink receiving layer on a substrate such as paper, synthetic paper, film and the like, and sheets not provided with an ink receiving layer are specifically mentioned. Be The ink-receptive layer may be, for example, impregnating or coating the above-mentioned base material with a cationic polymer; porous white inorganic substances capable of absorbing a colorant in an aqueous ink composition such as porous silica, alumina sol or special ceramics; It is provided by coating on the said base-material surface with hydrophilic polymers, such as alcohol and polyvinylpyrrolidone, etc .; Those provided with such an ink receptive layer are usually referred to as ink jet paper (film), glossy paper (film) or the like. Specific examples thereof include, for example, PICTRICCO made by Asahi Glass Co., Ltd .; Professional photo paper, Super Photo paper, Matte photo paper, Shiny gold, Platinum grade made by Canon Co., Ltd .; Photographic paper made by Seiko Epson Co., Ltd. Glossy), photo mat paper, photo paper Crispia (high gloss); premium plus photo paper manufactured by Nippon Hewlett-Packard Co., premium gloss film, photo paper, advanced photo paper; photo like QP manufactured by Konica Co., Ltd. For example, Fuji Photo Film Co., Ltd., Akira Photo Finishing Pro;
On the other hand, examples of the information transmission sheet not provided with the ink receiving layer include plain paper, high quality paper, and coated paper. Many kinds of plain paper are commercially available depending on the application. Examples of commercially available plain paper include double-sided high-quality plain paper manufactured by Seiko Epson Corporation; color plain paper manufactured by Canon Inc .; Multipurpose Paper manufactured by Hewlett Packard, All-in-one Printing Paper: Matte paper for inkjet manufactured by Mitsubishi Paper Industries Co., Ltd., trade name DL-9084; Premium multipurpose paper 4024 manufactured by Xerox Co., Ltd., and the like. Besides this, PPC (plain paper copy) paper and the like are also plain paper.

The aqueous ink composition is very clear on a recording material, has high saturation and high printing density, and gives a black recorded image of an ideal hue. In addition, the aqueous black ink composition of the present invention is free from solid deposition, physical property change, hue change and the like after storage for a long period of time, and the storage stability is extremely good.
The aqueous black ink composition of the present invention is used for ink jet recording and writing instruments, and even when used as an ink jet ink, solid deposition due to drying of the ink composition in the vicinity of the nozzle is very unlikely to occur. There is no need to close the The aqueous black ink composition of the present invention is also used when using a continuous ink jet printer and recirculating the ink at relatively long time intervals, or in intermittent use by an on demand ink jet printer, Does not cause changes in physical properties.
Furthermore, the image recorded by the aqueous black ink composition of the present invention is excellent in various fastness properties such as water resistance, moisture resistance, ozone gas resistance, abrasion resistance, light resistance and the like, particularly light resistance and water resistance.
Further, it is also excellent in long-term storage stability of the recording material, and is extremely excellent in light resistance and water resistance, in particular together with the hue on plain paper. It is also excellent in color development properties such as saturation, lightness, and printing density, color rendering properties, and sensor correspondence characteristics in the near infrared region.

  EXAMPLES The present invention will be described more specifically by the following examples, but 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 Colorant (I)] Synthesis Examples 1 to 3 In accordance with the method described in Patent Document 3, colorants represented by the following Formula (22), Formula (23) and Formula (26) (I) was synthesized respectively.

[(B) Preparation of aqueous ink composition]
[Examples 1 to 5 and Comparative Examples 1 to 6]
Each component listed in Table 6 below is mixed, stirred for approximately 1 hour to make a solution, and then filtered through a 0.45 μm membrane filter (trade name: cellulose acetate based filter paper manufactured by Advantec) for evaluation test. The aqueous ink composition of In addition, the numerical value of each component in following Table 6 means "part."

Also, abbreviations and the like in Table 6 below have the following meanings.
(I): Colorant (I).
(II): coloring agent (II).
AB2: C.I. I. Acid Black 2.
DO39: C.I. I. Direct Orange 39.
GLY: Glycerin.
2-PY: 2-pyrrolidone.
IPA: isopropyl alcohol.
BCA: butyl carbitol.
SF 440: Surfynol 440.
TEA: triethanolamine.

[(C) inkjet recording]
Ink jet recording was performed on the following plain papers 1 and 2 using the aqueous ink composition prepared in each of the examples and the comparative examples, using an ink jet printer manufactured by EPSON under the trade name PX105.
Plain paper 1: Premium multipurpose paper 4024 manufactured by Xerox Corporation.
Plain paper 2: manufactured by Mitsubishi Paper Industries Co., Ltd., matt paper for ink jet, trade name: DL-9084.
In the case of ink jet recording, an image pattern is formed so as to obtain six gradations of 100%, 80%, 60%, 40%, 20% and 10% density, and a dark black to light black gradation recorded matter I got The following evaluation tests were performed using this as a test piece.

[(D) Colorimeter and color measurement conditions]
When colorimetry is required in the following evaluation test, colorimetry was performed under the colorimeter and colorimetry conditions described below.
Colorimeter:
GRETAG-MACBETH company make, brand name SpectroEye.
Measurement conditions:
ANSI A as concentration standard, viewing angle 2 °, light source D50.

[(E) Hue evaluation test]
L *, a *, b * for the 100% density gradation portion of the test piece using plain paper 1 among the test pieces of each example and comparative example obtained in the above “(C) inkjet recording” Were measured, and the saturation C * value was calculated using the following formula.
C * = (a * ² + b * ² ) ^1/2
The obtained C * is a black color that is more preferable as it is closer to 0, and was evaluated based on the following four levels. In this standard, "B" or more is a normal practical black hue.
A: C * is less than 3.0.
B: C * is 3.0 or more and less than 4.0.
C: C * is 4.0 or more and less than 7.0.
D: C * is 7.0 or more.
The results are shown in Table 7 below.

[(F) Light resistance test]
After preparing the test piece which used the plain paper 1 among the test pieces of each Example and comparative example obtained by said "(C) inkjet recording", it air-dried for 24 hours. The dried test piece was placed in a xenon weatherometer XL75 (manufactured by Suga Test Instruments Co., Ltd.), and was irradiated for 72 hours at a temperature of 24 ° C., a humidity of 60% RH, and 100 kLux. After the completion of the irradiation, each test piece was subjected to color measurement to measure the color difference (ΔE) before and after the test. The smaller the obtained color difference ΔE, the smaller the color change due to light, and the better the light resistance.
A: ΔE is less than 3.0.
B: ΔE is 3.0 or more and less than 5.0.
C: ΔE is 5.0 or more and less than 8.0.
D: ΔE is 8.0 or more.
The results are shown in Table 7 below.

[(G) water resistance test]
After preparing the test piece which used the plain paper 2 among the test pieces of each Example and comparative example obtained by said "(C) inkjet recording", it air-dried for 24 hours. After immersing the dried test piece in ion exchange water for 10 minutes, the test piece was slowly taken out of the water and dried by natural drying for 24 hours. The color of this test piece was measured, and the remaining ratio (%) of Dk value before and after the test was calculated. In addition, the larger the obtained residual rate (%), the less the discoloration by water, and the better the water resistance.
A: Residual rate after test is 95% or more.
B: Residual rate after test is 93% or more and less than 95%.
C: Residual rate after test is 90 or more and less than 93%.
D: Residual rate after test is less than 90%.
The results are shown in Table 7 below.

  As is clear from the results of Table 7, each Example was found to give an achromatic, high quality black image. Furthermore, it is confirmed that the light resistance and the water resistance are excellent for each comparative example, and the content of the colorant (I) to the colorant (II) is extremely important for the improvement of the light resistance and the water resistance. It became clear.

  The aqueous ink composition of the present invention is excellent in hue, light fastness and water fastness, and therefore, it is extremely suitably used for various recording applications, particularly ink jet recording.

Claims (8)

At least two colorants of colorant (I) and colorant (II), and C.I. I. An aqueous ink composition comprising at least one colorant selected from Direct Orange, wherein the content of the colorant (I) in the total mass of the aqueous ink composition is that of the colorant (II) The coloring agent (I) is 2% by mass or more and 50% by mass or less with respect to the content, and the coloring agent (I) is a dye represented by the following formula (1) or a salt thereof. I. An aqueous ink composition that is Acid Black 2.
(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, a substituent A group selected from the group consisting of an alkoxy group which may be substituted, 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 alkoxy group which may have a substituent, and an alkyl group Represents a group.
n represents 0 or 1; ) The aqueous ink composition according to claim 1, further comprising a compound represented by the following formula (2) as a pH adjuster.
(In formula (2), R ₈ , R ₉ and R ₁₀ each independently represent a group selected from the group consisting of a hydrogen atom, an alkyl group, a hydroxyalkyl group, and a hydroxyalkoxyalkyl group.) 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; Aqueous 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 sulfo The aqueous ink composition according to claim 1, which is a group, R ₇ is a hydrogen atom, and n is 1.   The inkjet recording method which records by making the droplet of the water-based ink composition as described in any one of Claims 1-4 discharge according to a recording signal, and making it adhere to a to-be-recorded material.   The ink jet recording method according to claim 5, wherein the recording material is a sheet for information transmission.   The colored body which the water-based ink composition as described in any one of Claims 1-4 adhered.   An ink jet printer having a container containing the aqueous ink composition according to any one of claims 1 to 4.