JP2006225558A - Black water-based ink composition, inkjet recording method using the same, and recorded matter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a black water-based ink composition that is excellent in light resistance and ozone resistance, gives an excellent hue as a black ink on various media including plain paper, ensures a sufficient color development density, hardly suffers from clogging and exhibits excellent preservation stability. <P>SOLUTION: The black water-based ink composition comprises water, a water-soluble organic solvent, at least one black dye selected from the group consisting of compounds represented by formula (1) and salts thereof, and a complementary dye comprised of at least C. I. Direct Red 89, more preferably further comprised of C. I. Direct Yellow 86 and/or C. I. Direct Yellow 132, and exhibits an adjusted hue by incorporation of the complementary dye. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  INDUSTRIAL APPLICABILITY The present invention can be suitably used for inkjet recording, and is recorded by a black aqueous ink composition having excellent storage stability and excellent hue, an inkjet recording method using the ink composition, and the recording method. Related to the recorded material.

  The ink jet recording method is a known method in which ink composition is ejected as small droplets from a thin nozzle and characters and images are attached to the surface of the recording medium for recording. Ink-jet recording methods in practical use include: (i) an electrostrictive element is used to convert an electrical signal into a mechanical signal, and the ink composition stored in the nozzle head portion is intermittently ejected from the nozzle head by this mechanical signal. And (ii) rapidly heating a part very close to the discharge part of the nozzle head and storing the ink composition on the surface of the recording medium. There is a method of recording characters and images by generating bubbles, ejecting the ink composition intermittently from the nozzle head by the volume expansion of the bubbles, and attaching the ink composition to the surface of the recording medium.

  The ink composition used in the ink jet recording method is generally a solution in which various dyes are dissolved in water, an organic solvent, or a mixture thereof, and this ink composition is used for writing instruments such as fountain pens and ballpoint pens. Compared with other inks, higher safety and better printing characteristics are required.

  In recent years, inkjet printers have been adopted for the production of printed materials for advertisement, and printed materials produced by an ink jet recording method using a water-based ink composition are installed not only indoors but also outdoors. . Therefore, exposure to sunlight and / or light from various light sources and chemical substances such as ozone, nitrogen oxides, and sulfur oxides contained in the atmosphere may prevent the image quality of the printed matter from deteriorating over time. It is necessary. In response to this requirement, various studies have been made on color inks such as yellow, magenta, and cyan. The development of the black ink was delayed due to the low fastness of use in the image and the high concentration of the dye, because the fastness of the ink itself was higher than that of the color ink. However, the black ink is important from the viewpoint of obtaining image contrast in an image, and has been accelerated in recent years in combination with the improvement of the characteristics of the color ink.

  Under such circumstances, as a dye capable of improving the gas resistance, particularly ozone resistance of an ink composition using a dye as a colorant, for example, a disazo dye having the following structure is known (for example, (See Patent Document 1 and Patent Document 2).

  However, the ink composition using the dye has insufficient light resistance, ozone resistance, and the like, and there is a problem that the image quality of the printed material deteriorates with time, for example, fades when the printed material is exposed to light, ozone, or the like. there were.

Japanese Patent Laid-Open No. 3-229770 Japanese Patent Laid-Open No. 3-91576

As described above, while a black aqueous ink composition excellent in light resistance and ozone resistance is desired, the black aqueous ink composition has a hue desired for a hue, for example, neutral (achromatic color). It is also required that a sufficient color density can be secured, clogging is small, and the ink composition itself has excellent storage stability.

  INDUSTRIAL APPLICABILITY The present invention is capable of producing a printed matter that is excellent in light resistance and ozone resistance, can maintain a high-quality image over a long period of time, and has a black aqueous ink composition having an excellent hue as a black ink. Furthermore, the present invention provides a black aqueous ink composition having a sufficient color density and an excellent hue with respect to plain paper, with less clogging and excellent storage stability as an ink, and its ink composition The present invention is to provide an ink jet recording method using an article, and a recorded matter recorded by the ink jet recording method.

  In order to adjust the color tone of various black dyes, the present inventor prepared a number of black aqueous ink compositions obtained by adding various complementary color dyes to the black dye, and as a result of intensive studies on the characteristics thereof, in particular, the following formula (1) A black aqueous ink composition containing a specific complementary color dye in a black dye comprising a compound represented by formula (1) and / or a salt thereof ensures an excellent color density as a black ink and adjusts the mixing ratio of the complementary color dye As a result, the hue of various media including plain paper is improved and ink storage stability and clogging reliability are ensured, and the object of the present invention can be achieved. Arrived.

（前記式（１）中、Ｒ¹は置換基を有するフェニル基又は置換基を有するナフチル基を表し、Ｒ²は置換基を有するフェニレン基又は置換基を有するナフチレン基を表し、Ｒ³は少なくとも１つの二重結合及び置換基を有する５〜７員環の複素環基を表す。さらに前記Ｒ¹〜Ｒ³における前記置換基は独立して、ＯＨ、ＳＯ₃Ｈ、ＰＯ₃Ｈ₂、ＣＯ₂Ｈ、ＮＯ₂、Ｃ１〜４のアルキル基、置換基を有するアルキル基、Ｃ１〜４のアルコキシ基、置換基を有するアルコキシ基、置換基を有するアミノ基、及び置換基を有するフェニル基からなる群から選ばれる。）
で表される化合物及びその塩からなる群から選ばれる少なくとも一種の黒色染料と、補色染料として少なくともＣ．Ｉ．ダイレクトレッド８９を含み、該補色染料を添加することによって色相が調整されていることを特徴とするものである。 The black aqueous ink composition of the present invention comprises water, a water-soluble organic solvent,
Following formula (1):

(In the formula (1), R ¹ represents a phenyl group having a substituent or a naphthyl group having a substituent, R ² represents a phenylene group having a substituent or a naphthylene group having a substituent, and R ³ is at least It represents a 5- to 7-membered heterocyclic group having one double bond and a substituent, and the substituent in R ^{1 to} R ³ is independently OH, SO ₃ H, PO ₃ H ₂ , CO ₂ H, NO ₂ , a C1-4 alkyl group, a substituted alkyl group, a C1-4 alkoxy group, a substituted alkoxy group, a substituted amino group, and a substituted phenyl group Selected from group.)
At least one black dye selected from the group consisting of a compound represented by formula (I) and a salt thereof, and at least C.I. I. Including Direct Red 89, the hue is adjusted by adding the complementary color dye.

（前記式（２）中、Ｒ¹〜Ｒ⁹は独立して、Ｈ、ＳＯ₃Ｈ、ＰＯ₃Ｈ₂、ＣＯ₂Ｈ及びＮＯ₂からなる群から選ばれる基を表す。）
で表される化合物であることが好ましい。 The black aqueous ink composition of the present invention may further include C.I. I. Direct Yellow 86 and / or C.I. I. Preferably, direct yellow 132 is included.
In the black aqueous ink composition of the invention, the compound represented by the formula (1) is represented by the following formula (2):

(In the formula (2), R ^{1 to} R ⁹ independently represent a group selected from the group consisting of H, SO ₃ H, PO ₃ H ₂ , CO ₂ H and NO _2. )
It is preferable that it is a compound represented by these.

In the black aqueous ink composition of the invention, the black dye is preferably contained in an amount of 0.5 to 12.0% by weight based on the total weight of the black aqueous ink composition.
The black aqueous ink composition of the present invention includes the C.I. I. The direct red 89 is preferably contained in an amount of 0.02 to 3.5% by weight based on the total weight of the black aqueous ink composition.

The black aqueous ink composition of the present invention includes C.I. I. Direct Yellow 86 and / or C.I. I. The direct yellow 132 is preferably contained in an amount of 0.02 to 2.5% by weight based on the total weight of the black aqueous ink composition.
The black aqueous ink composition of the invention includes the black dye and the C.I. I. It is preferable to contain Direct Red 89 in a weight ratio of 15: 1 to 10: 4.
Furthermore, the black aqueous ink composition of the invention includes the black dye and the C.I. I. Direct Yellow 86 and / or C.I. I. It is preferable to contain direct yellow 132 in a weight ratio of 20: 1 to 10: 3.

  The black aqueous ink composition of the present invention preferably contains a nonionic surfactant in the black ink composition.

In the black aqueous ink composition of the invention, it is preferable that the nonionic surfactant is an acetylene glycol surfactant.
Furthermore, the black aqueous ink composition of the present invention preferably contains 0.1 to 5% by weight of the nonionic surfactant.

The black aqueous ink composition of the present invention preferably contains a penetration accelerator in the black ink composition.
In the black aqueous ink composition of the invention, the penetration accelerator is preferably a glycol ether.

  The inkjet recording method of the present invention is characterized in that the black aqueous ink composition of the present invention is ejected as droplets from a thin nozzle, and the droplets are adhered to a recording medium.

  The recorded matter of the present invention is printed by the ink jet recording method.

  The black aqueous ink composition of the present invention comprises at least C.I. in order to adjust the hue of the black dye having the specific chemical structure represented by the composition formula (1) and the ink using this black dye. I. By including a specific amount of Direct Red 89 in the black aqueous ink composition as a complementary color dye, the hue of the black aqueous ink composition can be adjusted to a desired hue even when printed on various media including plain paper. Can do. In addition, there is little clogging, a sufficient color density is secured, and the storage stability as ink is excellent. Furthermore, an image printed using the black aqueous ink composition of the present invention is excellent in light resistance and ozone resistance.

  The inventors of the present invention include a black aqueous ink containing a black dye having a specific chemical structure represented by the composition formula (1) and a specific dye (complementary dye) for adjusting the hue of the specific black dye. The composition has an excellent hue, and by using this black aqueous ink composition, in addition to obtaining a printed matter having an image excellent in light resistance and ozone resistance, the storage stability of the ink is also obtained. And it discovered that it was excellent in clogging property. The present invention has been completed based on these findings.

で表される化合物及び式（１）で表される化合物の塩からなる群（以下、あわせて「式（１）の染料」という。）から選ばれる一種以上を含有するとともに、式（１）の染料の色相を調整するために、式（１）の染料以外の下記の特定の補色染料を必須成分として含むものである。 The black water-based ink composition of the present invention (hereinafter also referred to as “black ink composition”) is represented by the following formula (1) in water or an aqueous medium comprising water and a water-soluble organic solvent:

And at least one selected from the group consisting of a compound represented by formula (1) and a salt of the compound represented by formula (1) (hereinafter collectively referred to as “dye of formula (1)”), and formula (1) In order to adjust the hue of the dye, the following specific complementary dye other than the dye of the formula (1) is contained as an essential component.

In the formula (1), R ¹ represents a phenyl group having a substituent or a naphthyl group having a substituent. Further, in formula (1), R ² represents a phenylene group having a substituent or a naphthylene group having a substituent. Further, in formula (1), R ³ represents a 5- to 7-membered heterocyclic group having at least one double bond and a substituent. Further, the substituents in R ^{1 to} R ³ are independently OH, SO ₃ H, PO ₃ H ₂ , CO ₂ H, NO ₂ , a C1-4 alkyl group, a substituted alkyl group, a C1-4 It represents a group selected from the group consisting of an alkoxy group, a substituted alkoxy group, a substituted amino group, and a substituted phenyl group.

Further substituted alkyl groups of said, OH, is selected from SO ₃ H, C1 -4 alkyl groups substituted with one or more groups selected from the group consisting of PO ₃ H ₂ and CO ₂ H group It is preferable. Also, substituted alkoxy groups above, OH, SO ₃ H, be selected from C1~4 alkoxy group substituted with one or more groups selected from the group consisting of PO ₃ H ₂ and CO ₂ H Is preferred. Further, an amino group substituted Said, one 1 OH, SO ₃ H, a C1~4 alkyl group substituted with one or more groups selected from the group consisting of PO ₃ H ₂ and CO ₂ H Alternatively, it is preferably selected from the group consisting of two amino groups. The substituted phenyl group is selected from the group consisting of OH, SO ₃ H, PO ₃ H ₂ , CO ₂ H, a C1-4 alkyl group, and a substituted C1-4 alkyl group. It is preferably selected from the group consisting of phenyl groups having one or two substituents.

（式（２）中、Ｒ¹〜Ｒ⁹は独立して、Ｈ、ＯＨ、ＳＯ₃Ｈ、ＰＯ₃Ｈ₂、ＣＯ₂Ｈ、ＮＯ₂及びＮＯ₂からなる群から選ばれる基を表す。）
で表される化合物であることが特に好ましい。 Further, the compound represented by the formula (1) used in the present invention includes the following formula (2):

(In the formula (2), R ^{1 to} R ⁹ independently represent a group selected from the group consisting of H, OH, SO ₃ H, PO ₃ H ₂ , CO ₂ H, NO ₂ and NO _2. )
The compound represented by the formula is particularly preferred.

  As the compound represented by the formula (1) used in the ink composition of the present invention, compounds represented by the following formulas (3) to (9) are particularly preferable.

The compound represented by the formula (1) or formula (2) used in the ink composition of the present invention can be appropriately synthesized using a preferred method. For example, each compound is bound by three azo groups. It can be synthesized by combining building blocks having each of the four corresponding structures by azo coupling. That is, for example, when the dihydroxynaphthalene skeleton portion represented by the formula (1) is represented by Q, the compound of the formula (1) is R ³ N═N—R ² —N═N—Q—N═N—R ¹ Can be expressed as One specific method for synthesizing this compound is schematically shown. First, a diazonium salt obtained by diazotizing R ¹ —NH ₂ is reacted with QH to give R ¹ —N═N—QH. Next, the compound obtained by diazotizing CH ₃ CON-R ² —NH ₂ and R ¹ —N═N—QH are coupled to give R ¹ —N═NQN═N—R ² NCOCH ₃ . Synthesize. The acetyl group of this compound is removed to form an amino group and then diazotized, followed by coupling with R ³ H to synthesize R ¹ —N═N—Q—N═N—R ² —N═N—R ^3. it can.

Furthermore, as a specific example of synthesis, a synthesis example of the compound represented by the formula (3) will be described below.
5-acetylamino-2-aminobenzenesulfonic acid (23.0 g, 0.10 mol) was added to water (300 ml) containing concentrated nitric acid (30 ml). Sodium nitrite (6.9 g) was added over 10 minutes at a temperature of 0-5 ° C. After 60 minutes, excess nitrous acid was decomposed, and the resulting diazonium salt solution was slowly dissolved in water (500 g) while maintaining the pH of 8 to 9 at 5 to 10 ° C. To a solution of naphthalene-3,6-disulfonic acid (32.0 g, 0.10 mol). It was confirmed by HPLC that this reaction proceeded quantitatively. This gave a solution containing the coupling product (referred to as dye base).

Then 5-nitro-2-aminobenzenesulfonic acid (43.6 g, 0.20 mol) was added to water (500 g) containing concentrated hydrochloric acid (60 g). Sodium nitrite (13.8 g) was added over 15 minutes at a temperature of 0-5 ° C. After 60 minutes, the obtained diazonium salt solution was added to the dye base to which tetrahydrofuran (1000 g) had been previously added over 120 minutes while maintaining 5 to 10 ° C and pH 6 to 7. After 5 hours, the resulting precipitate was collected and dried in a dryer to give a dark red solid (55.3 g). This dark red solid was dissolved in water (1000 ml) and heated to 80 ° C. Sodium hydroxide (10 g) was added and the temperature was kept at 80 ° C. for an additional 8 hours. After 8 hours, the pH was adjusted to 7-8 using concentrated hydrochloric acid, and the solution was allowed to cool to room temperature. The solution was dialyzed (less than 50 μScm ⁻¹ ) using Visking ™ tubing, then filtered using a filter and dried in a dryer to yield 47.2 g of a black solid.

The black solid obtained above was redissolved in water at pH 7-9, but lithium hydroxide was used to adjust the pH. Then sodium nitrite (8.3 g) was added and stirred for 10 minutes. The dye / nitrite solution was then transferred into ice water (100 ml) containing concentrated hydrochloric acid (30 g). On standing, the temperature rose to 15-25 ° C., but was left for 3 hours. The obtained diazodium salt solution was charged with 1- (4-sulfophenyl) -3-carboxy-5-pyrazolone (17.9 g, 0.06 mol) over 120 minutes while maintaining pH 15 to 20 ° C. and pH 6 to 7. ). This pH was maintained by adding lithium hydroxide. The solution is then dialyzed (less than 50 μScm ⁻¹ ) using Visking ™ tubing, further filtered using a filter and dried in a drier to yield 60.0 g of the compound represented by the formula (3). Obtained as a black solid.

Examples of the salt of the compound represented by the formula (1) for use in the black ink composition of the present invention include a compound represented by the formula (1) that is a proton such as OH, SO ₃ H, or PO ₃ H ₂ group. When it has an acid group, the alkali metal salt of the proton acid group, for example, lithium salt, sodium salt, and potassium salt is preferable, and lithium salt and sodium salt are particularly preferable. By using the alkali metal salt of the compound represented by the formula (1), a black ink composition having excellent storage stability can be obtained.

  The dye of the formula (1) used in the black ink composition of the present invention itself has a completely neutral hue, that is, not an achromatic color, and generally has a bluish hue. In the present invention, the black ink composition contains a predetermined amount of C.I. as a complementary dye in addition to the dye of formula (1). I. Direct Red 89, and more preferably, C.I. I. Direct Yellow 86 and / or C.I. I. By adding the direct yellow 132, the hue of the black ink using the dye of the formula (1) is adjusted. In general, since the hue of the black ink composition is preferably an achromatic color, it is particularly preferable to adjust the hue to an achromatic color, but it can also be adjusted to a hue other than an achromatic color if desired. In the present invention, the dye of formula (1) and C.I. I. Direct Red 89 is added, and if necessary, C.I. I. Direct Yellow 86 and / or C.I. I. A specific amount of direct yellow 132 as a complementary color dye is added and mixed to adjust the hue of the black ink composition to a desired hue. The black ink composition of the present invention obtained by using such a dye is excellent in image storability of printed matter (recorded matter), has excellent storage stability, and provides a sufficient color density. Play. In addition, since this complementary color dye can be easily dissolved in an aqueous solvent, ink clogging is improved and the storage stability of the ink is ensured.

  The complementary dyes other than the dye of the formula (1) used in the black ink composition of the present invention are an orange dye and a yellow dye having a hue different from that of the dye of the formula (1). A predetermined amount of each of the complementary color dyes other than the dye of the formula (1) is added to the dye of the formula (1) and added to the black ink composition, so that the black ink composition has a desired hue. Since the dye of formula (1) is generally bluish, in order to neutralize the hue of the black ink composition, the hue is adjusted by adding the orange dye and the yellow dye to the black ink composition.

Next, an orange dye and a yellow dye, which are complementary dyes added to the black dye in order to adjust the hue of the black ink composition of the present invention, will be described.
C. used as a complementary dye in the present invention I. Direct Red 89 is a dye that has an orange hue, has no primary amino group, is not an ammonium salt, and is not a salt with an organic cation.
This dye has a water solubility of 8 wt% or more at room temperature.

  In the present invention, C.I. I. C. used with Direct Red 89 I. Direct Yellow 86 and / or C.I. I. Direct Yellow 132 is also the C.I. I. Like direct red 89, it is a dye that does not have a primary amino group, is not an ammonium salt, and is not a salt with an organic cation. Note that C.I. I. The water solubility of direct yellow 132 at room temperature is about 8 wt%. I. The water solubility of direct yellow 86 at room temperature is about 5 wt%.

Next, the amount of dye contained in the black ink composition of the present invention will be described. The black ink composition of the present invention contains at least one dye of the above formula (1) as a black dye, and other than the dye of the formula (1) for adjusting the hue, the above-mentioned C.I. I. Including Direct Red 89, and C.I. I. Direct Yellow 86 and / or C.I. I. In this case, the amount of the complementary dye other than the dye of the formula (1) contained in the black ink composition of the present invention is adjusted so that the hue of the black ink composition can be adjusted to a desired hue. It can be determined as appropriate. However, it is generally preferable to use dyes in the amounts shown below.

  In the black ink composition of the present invention, at least one dye of the formula (1) is contained as a black dye, and the dyes of the formula (1) are added to the total weight of the black ink composition. It is preferably contained in an amount of 0.5 to 12.0% by weight, and more preferably 1.0 to 10.0% by weight. When the total amount of the dye of the formula (1) contained in the black ink composition is 0.5% by weight or more, sufficiently good color development when an image or the like is recorded on the recording medium using the ink composition, And a high image density can be obtained. Further, by setting the content of the dye of the formula (1) contained in the black ink composition to 12.0% by weight or less, the viscosity of the ink composition can be adjusted to a preferable value, and the ink jet head. The amount of ink composition discharged from the ink can be stabilized, and further, clogging of the ink jet head can be prevented.

  C. contained in the black ink composition of the present invention. I. Direct red 89 is preferably contained in an amount of 0.02 to 3.5% by weight, more preferably 0.1 to 2.5% by weight, based on the total weight of the black ink composition.

  C. contained in the black ink composition of the present invention. I. Direct Yellow 86 and / or C.I. I. The direct yellow 132 is preferably contained in an amount of 0.02 to 2.5% by weight, more preferably 0.1 to 2.0% by weight, based on the total weight of the black ink composition.

  In addition, the black ink composition of the present invention contains at least one of the dyes of the formula (1) as a black dye and the C.I. I. When the direct red 89 is contained, the black dye and the C.I. I. It is preferable that Direct Red 89 is contained in a weight ratio of 15: 1 to 10: 4 from the viewpoint that a hue favorable as a black ink composition can be obtained.

Further, the black ink composition of the present invention contains at least one dye of the formula (1) as a black dye together with the C.I. I. Direct Yellow 86 and / or C.I. I. When the direct yellow 132 is contained, the black dye and the C.I. I. Direct Yellow 86 and / or C.I. I. It is preferable that the direct yellow 132 is contained in a weight ratio of 20: 1 to 10: 3 from the viewpoint of obtaining a preferable hue as the black ink composition.

  In the black ink composition of the present invention, the complementary dye contained together with at least one of the dyes of the formula (1) is the C.I. I. In addition to Direct Red 89, the C.I. I. Direct Yellow 86 and / or C.I. I. Including direct yellow 132 is more preferable in adjusting to a desired color tone. In that case, at least one black dye of the dye of formula (1) in the black ink composition; I. Direct Red 89 and the C.I. I. Direct Yellow 86 and / or C.I. I. The content by weight ratio with respect to direct yellow 132 depends on the desired color tone of the black ink composition to be obtained. I. The weight ratio of direct red 89 is 15: 1 to 10: 4, and black dye: C.I. I. Direct Yellow 86 and / or C.I. I. The weight ratio of direct yellow 132 is appropriately selected within a range of 20: 1 to 10: 3.

  The black ink composition of the present invention comprises at least one dye of the formula (1) and a complementary color dye for adjusting the hue (CI Direct Red 89, and CI Direct Yellow 86 and / or C.I. I. Direct Yellow 132) can be prepared by dissolving in a solvent containing water. The solvent used in the ink composition of the present invention is preferably water or a mixture of water and a water-soluble organic solvent. Examples of the water-soluble organic solvent used in the present invention include amides such as dimethylformamide and dimethylacetamide; ketones or ketoalcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; ethylene glycol, propylene glycol, 1, Alkylene glycols such as 5-pentanediol, triethylene glycol and diethylene glycol; glycerin; polyalkylene glycols such as polyethylene glycol and polypropylene glycol; alkyl alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol and n-butyl alcohol Urea; and 2-pyrrolidone, sulfolane, pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, etc. One or more selected from the group consisting of sexual organic solvent can be exemplified. The water-soluble organic solvent used in the present invention preferably has a lower vapor pressure than water at room temperature.

  It is possible to increase the permeability of the ink composition to the recording medium, and when color printing is performed, the ink is less likely to bleed at the boundary where the black ink of the present invention and the color ink adjacent thereto are in contact with each other. Since an image can be obtained, it is particularly preferable that a glycol ether-based water-soluble organic solvent is contained in the black ink composition of the present invention as a penetration accelerator. Examples of the glycol ether water-soluble organic solvent used in the present invention include ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, propylene glycol monobutyl ether, diethylene glycol Propylene glycol monobutyl ether, triethylene glycol monobutyl ether and the like are preferable.

  When the black ink composition of the present invention contains a glycol ether water-soluble organic solvent, the proportion of the glycol ether water-soluble organic solvent contained in the black ink composition is not particularly limited, and those skilled in the art The ratio can be determined as appropriate so as not to impair the effects of the invention. However, the black ink composition of the present invention preferably contains 3 to 30% by weight, more preferably 5 to 20% by weight, of a glycol ether-based water-soluble organic solvent. By making the amount of the glycol ether water-soluble organic solvent contained in the black ink composition 3% by weight or more, the penetrability of the ink into the recording medium can be enhanced. Further, in color printing, the black ink of the present invention is used. Ink bleeding (bleeding) can be made difficult to occur at the boundary between the image formed by the above and the image formed by the color ink. In addition, by making the amount of the glycol ether-based water-soluble organic solvent contained in the black ink composition 30% by weight or less, it is possible to make the image formed on the recording medium difficult to bleed using the black ink composition. The ink composition can be kept in a uniform state without separation. When the black ink composition is separated, it is necessary to add a solubilizing agent for dissolving the glycol-based water-soluble organic solvent used in water to make the black ink composition uniform. Addition increases the viscosity of the black ink composition, which may make it difficult to eject the black ink composition with an inkjet head. In addition, the glycol ether type water-soluble organic solvent can use only 1 type, and can use 2 or more types together.

  A surfactant can be further added to the black ink composition of the present invention. As the surfactant used in the present invention, a nonionic surfactant is preferable. When a nonionic surfactant is added to the black ink composition of the present invention, the black ink composition is easily penetrated and fixed on the recording medium, and is formed by a drop of ink ejected onto the recording medium by an ink jet method. By making the shape of the image to be close to a perfect circle, the image quality of the obtained image can be improved.

（式（１０）中、Ｒ¹、Ｒ²、Ｒ³、及びＲ⁴はそれぞれ独立して、Ｃ１〜Ｃ６の直鎖、環式又は分枝アルキル鎖を表し、さらにＡ¹Ｏ及びＡ²Ｏはそれぞれ独立してＣ２〜Ｃ３のオキシアルキレン鎖、例えばオキシエチレンまたはオキシプロピレン、またはＣ２〜Ｃ３のアルキレンオキサイドが重合または共重合して得られるポリオキシアルキレン鎖、例えばポリオキシエチレン鎖、ポリオキシプロピレン鎖、もしくはポリオキシエチレンプロピレン鎖を表す。また式中、ｎ及びｍはＡ¹ＯまたはＡ²Ｏ単位、すなわちオキシアルキレンの繰り返し数を表し、０≦ｎ＜３０、０≦ｍ＜３０、及び０≦ｎ＋ｍ＜５０を満たす数である。）で表される化合物を用いることが好ましい。このアセチレングリコール系界面活性剤としては、例えば、サーフィノール４６５（商標）、サーフィノール１０４（商標）（以上商品名、Air Products and Chemical社製）、オルフィンＳＴＧ（商標）、オルフィンＥ１０１０（商標）（以上商品名、日信化学工業株式会社製）を例示することができ、これらから選ばれる一種以上を本発明のブラックインク組成物に添加することが好ましい。 As the nonionic surfactant to be contained, for example, an acetylene glycol surfactant is preferably used, but is not limited thereto. As the acetylene glycol surfactant used in the black ink composition of the present invention, in particular, the following formula (10):

(In the formula (10), R ¹ , R ² , R ³ , and R ⁴ each independently represent a C1-C6 straight chain, cyclic, or branched alkyl chain, and A ¹ O and A ² O Are each independently a C2-C3 oxyalkylene chain, such as oxyethylene or oxypropylene, or a polyoxyalkylene chain obtained by polymerization or copolymerization of C2-C3 alkylene oxide, such as a polyoxyethylene chain, polyoxypropylene A chain or a polyoxyethylenepropylene chain, wherein n and m represent A ¹ O or A ² O units, ie, the number of oxyalkylene repeats, 0 ≦ n <30, 0 ≦ m <30, and It is a number satisfying 0 ≦ n + m <50). Examples of the acetylene glycol surfactant include Surfynol 465 (trademark), Surfynol 104 (trademark) (trade name, manufactured by Air Products and Chemical Co., Ltd.), Olfine STG (trademark), Olfine E1010 (trademark) ( As mentioned above, trade names, manufactured by Nissin Chemical Industry Co., Ltd.) can be exemplified, and it is preferable to add one or more selected from these to the black ink composition of the present invention.

  In the present invention, for example, the surfactant is contained in the black ink composition such that the surfactant is contained in an amount of preferably 0.1 to 5% by weight, more preferably 0.5 to 2% by weight. An activator may be added. By containing the surfactant in an amount of 0.1% by weight or more with respect to the black ink composition, the permeability of the ink composition with respect to the recording medium can be increased. Further, when the amount of the surfactant contained in the black ink composition is 5% by weight or less, an effect that an image formed on the recording medium by the black ink composition is difficult to blur can be obtained.

  If desired, the black ink composition of the present invention may further contain a humectant, a viscosity modifier, a pH adjuster, and other additives that can be used in the black ink composition. Specifically, water-soluble oligomers and water-soluble polymers such as sodium alginate, water-soluble resins, antioxidants, ultraviolet absorbers, preservatives, fungicides, rust inhibitors, and the like are added to the ink composition of the present invention. be able to. Those skilled in the art can use the preferable additive selected in a preferable amount as long as the effects of the present invention are not impaired.

  The black ink composition of the present invention preferably has a pH of 7.0 to 9.0 at 20 ° C., more preferably 7.4 to 8.5. By making the pH of the ink composition at 20 ° C. 7.0 or more, it is possible to prevent the eutectoid plating of the ink jet head from being peeled off, and to stabilize the ejection characteristics of the ink composition from the ink jet head. Can do. Further, by setting the pH of the black ink composition to 9.0 or less at 20 ° C., it is possible to prevent deterioration of various members that come into contact with the black ink composition, such as members constituting an ink cartridge or an inkjet head. Can do.

  In the present invention, it is preferable to adjust the pH of the black ink composition at 20 ° C. to a preferred value by adding a pH adjuster to the black ink composition. Examples of the pH adjuster that can be used in the present invention include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, and amines such as triethanolamine, diethanolamine, and tripropanolamine. It is preferable to use it. The addition amount of the pH adjusting agent to the black ink composition is an amount that allows the pH of the black ink composition to fall within the above-mentioned preferable range, and the amount can be appropriately determined.

  In order to prepare the black ink composition of the present invention, for example, each component to be contained in the black ink composition is sufficiently mixed to obtain a uniform solution, and then a membrane filter having an average aperture of 0.8 μm is formed. It is possible to use a method of defoaming under reduced pressure after using and pressure-filtering.

  The black ink composition of the present invention can be used for general writing instruments, recorders, pen plotters, and the like, but is particularly preferably used for an ink jet recording method. The inkjet recording method in which the black ink composition of the present invention can be used includes any recording method in which the black ink composition is ejected as droplets from a thin nozzle and the droplets are attached to a recording medium. Specific examples of the ink jet recording method in which the black ink composition of the present invention can be used will be described below.

  The first method is a method called an electrostatic attraction method. In the electrostatic suction method, a strong electric field is applied between the nozzle and the acceleration electrode arranged in front of the nozzle, and droplet-like ink is continuously ejected from the nozzle, and the ink droplet passes between the deflection electrodes. In the meantime, by applying a printing information signal to the deflection electrode, the ink droplets are blown toward the recording medium and the ink is fixed on the recording medium, or an image is recorded without deflecting the ink droplets. In this method, an image is fixed on a recording medium by ejecting ink droplets from a nozzle onto the recording medium in accordance with a print information signal. The ink composition of the present invention is preferably used in a recording method using this electrostatic suction method.

  The second method is a method for forcibly ejecting ink droplets from the nozzles by applying pressure to the ink liquid with a small pump and mechanically vibrating the ink jet nozzles with a quartz vibrator or the like. The ink droplet ejected from the nozzle is charged at the same time as it is ejected, and while the ink droplet passes between the deflection electrodes, a print information signal is given to the deflection electrode to fly the ink droplet toward the recording medium, This is a method for recording an image on a recording medium. The ink composition of the present invention is preferably used in this recording method.

  The third method is a method in which an image is recorded on a recording medium by simultaneously applying a pressure and a printing information signal to the ink liquid by a piezoelectric element, and ejecting ink droplets from a nozzle toward the recording medium. The ink composition of the present invention is preferably used in this recording method.

  In the fourth method, the ink liquid is heated and foamed using microelectrodes according to the print signal information, and the bubbles are expanded to eject the ink liquid from the nozzle toward the recording medium, thereby forming an image on the recording medium. It is a method of recording. The ink composition of the present invention is preferably used in this recording method.

  The black aqueous ink composition of the present invention is particularly preferable as a black ink composition used when an image is recorded on a recording medium using an image recording method based on an ink jet recording method including the four methods described above. The recorded matter recorded using the black ink composition of the present invention has excellent image quality, and is also excellent in light resistance and ozone resistance.

  EXAMPLES The present invention will be described more specifically based on examples below, but the present invention is not limited to the following examples.

[Preparation of black ink composition]
Example 1 After mixing each component to make a uniform solution based on the blending ratio shown in Table 1 below, the obtained solution was filtered under pressure using a membrane filter having an average aperture of 0.8 μm. 2 and Comparative Examples 1 and 2 were obtained.

で表される化合物のリチウム塩である。このブラック染料１は、前記式（１）及び式（２）で表される化合物のアルカリ金属塩の例である。
また、比較例２で使用するマゼンタ染料１は以下の式（１１）で表される化合物である。このマゼンタ染料１及びＣ．Ｉ．ダイレクトイエローＣ．Ｉ．１７３は、共に水溶性基のカウンターイオンがアンモニウムイオンであり、また、その水溶性が室温で約５ｗｔ％程度の染料である。

The black dye 1 in Table 1 has the following formula (3):

It is a lithium salt of the compound represented by these. This black dye 1 is an example of the alkali metal salt of the compound represented by the formula (1) and the formula (2).
The magenta dye 1 used in Comparative Example 2 is a compound represented by the following formula (11). This magenta dye 1 and C.I. I. Direct Yellow C.I. I. 173 is a dye whose water-soluble group counter ion is ammonium ion and whose water solubility is about 5 wt% at room temperature.

[Printing of test records]
A printing test was performed using an inkjet printer Stylus Color 880 (trademark) (trade name, manufactured by Seiko Epson Corporation). Each black ink composition of Examples 1 and 2 and Comparative Examples 1 and 2 was filled in the black ink cartridge for this printer, and printed on EPSON photographic paper (trade name, manufactured by Seiko Epson Corporation, model number: KA420PSK). To obtain a recorded material. Printing was performed by adjusting the duty so that the OD (Optical Density) of the obtained image was in the range of 0.9 to 1.1. The obtained recorded matter was allowed to stand in a dark place at room temperature for 1 day, and then each test of light resistance and gas resistance (ozone resistance) of the recorded image was performed as follows. In addition, the hue of the image was also measured using the obtained recorded matter. For hue, PUREMIUM MULTIPURPOSE 4024 PAPER (trade name, manufactured by XEROX) was also evaluated as an example of plain paper.

(Light resistance test)
The light resistance test was performed on the recorded matter using a fluorescent light resistance tester SFT-II (trade name, manufactured by Suga Test Instruments Co., Ltd.) under the conditions of a temperature of 24 ° C., a humidity of 60 RH%, and an illuminance of 70000 lux. It was carried out by light irradiation for 21 days. Using a reflection densitometer Spectrolino (trade name, manufactured by GRETAG), the OD value of the recorded image before and after light irradiation was measured, and ROD was calculated by the following formula. The OD value was measured at a light source of D50, no light source filter, absolute white as a white standard, and a viewing angle of 2 °.
ROD (%) = (Dn / Do) × 100
(Where Dn is the OD value of the image after the end of the light irradiation test, Do is the OD value of the image before the start of the light irradiation test)
From the measured value (OD value) calculated from the above formula, the optical density residual ratio (ROD) of the image of each recorded matter after light irradiation was obtained by calculation.

Based on the obtained ROD, the light resistance of the recorded material was evaluated by ranking the test results A to D using the following criteria.
A: ROD is 80% or more.
B: ROD is 60% or more and less than 80% C: ROD is 40% or more and less than 60% D: ROD is less than 40% A higher ROD value is preferable because there is less image deterioration due to light irradiation. The obtained results are shown in Table 2.

[Gas resistance (ozone resistance) test]
Ozone weather meter OMS-H type (trade name, manufactured by Suga Test Instruments Co., Ltd.) was used, and the recorded matter was subjected to ozone for 24 hours under the conditions of a temperature of 24 ° C., a humidity of 60% RH, and an ozone concentration of 10 ppm. Exposed to. Using a reflection densitometer Spectrolino (trade name, manufactured by GRETAG), the OD value (Optical Density) of the recorded material before and after ozone exposure was measured. The measurement was performed under the conditions that the light source was D50, no light source filter, absolute white was used as a white standard, and the viewing angle was 2 °. Using the same calculation method as the calculation method in the light resistance test and the same criterion as the criterion in the light resistance test, the obtained results are ranked A to D to evaluate the ozone resistance of the recorded matter. did. The obtained evaluation results are shown in Table 2 together with the light resistance test results. Higher ROD values result in less image degradation due to ozone exposure.

表２に示した結果からわかるように、耐光性及び耐オゾン性に関しては本発明のブラックインク組成物（実施例１、２のインク組成物）も従来のブラックインク組成物（比較例１、２のインク組成物）もともに良好である。

As can be seen from the results shown in Table 2, with respect to light resistance and ozone resistance, the black ink compositions of the present invention (ink compositions of Examples 1 and 2) are also conventional black ink compositions (Comparative Examples 1 and 2). The ink composition is also good.

[Ink storage stability test]
Each black ink composition of Examples 1 and 2 and Comparative Examples 1 and 2 was held at 70 ° C. for 6 days to conduct a storability test. Next, the black ink composition before the test and the black ink composition after the test were each diluted 2000 times by volume with ultrapure water, and the absorbance was measured using a spectrophotometer. Was measured. The absorbance at the maximum absorption wavelength (λmax) in the visible region of the ink composition before the storage test is compared before and after the storage test, and the change in absorbance by the storage test is defined as the “residual ratio” and the following calculation formula:
Residual rate (%) = absorbance of ink after holding at 70 ° C. for 6 days / absorbance of initial ink × 100
Calculated using The higher the “residual ratio” calculated by the above equation, the better the storage stability of the ink.
The obtained “residual rate” results are shown in Table 3. The ink storage stability at this time was evaluated by ranking as follows.
A: Residual rate is 95% or more B: Residual rate is 90% or more and less than 95% C: Residual rate is 85% or more and less than 90% D: Residual rate is less than 85%

表３からわかるように、ブラック染料１に加え、補色染料として少なくともＣ．Ｉ．ダイレクトレッド８９を含むブラックインク組成物（実施例１及び２のブラックインク組成物）の保存安定性は良好であるが、同じブラック染料１にＣ．Ｉ．ダイレクトレッド８９や、Ｃ．Ｉ．ダイレクトイエロー８６及び／又はＣ．Ｉ．ダイレクトイエロー１３２以外の補色染料を含有させる（比較例２のブラックインク組成物）とインクの保存安定性は大きく低下する。
なお、組成中に補色染料を含まない比較例１のブラックインク組成物では実施例のインク組成物と同様にインク保存性は良好であった。

As can be seen from Table 3, in addition to black dye 1, at least C.I. I. Although the storage stability of the black ink composition containing Direct Red 89 (the black ink compositions of Examples 1 and 2) is good, C.I. I. Direct Red 89 and C.I. I. Direct Yellow 86 and / or C.I. I. When a complementary color dye other than direct yellow 132 is contained (the black ink composition of Comparative Example 2), the storage stability of the ink is greatly reduced.
In addition, the black ink composition of Comparative Example 1 which does not contain a complementary color dye in the composition had good ink storage stability like the ink compositions of the examples.

[Hue of black ink composition]
As for the hue of the black ink composition, the hue of the image is visually evaluated, and the most achromatic color is felt as the “most preferred hue”, and the slightest hue such as cyan is felt as the “preferred hue”. The colors where cyan, green, and purple colors are clearly felt were expressed as “cyan”, “green”, and “purple”, respectively. Table 4 shows the obtained results.

表４からわかるように、色相に関しては本発明のブラックインク組成物（実施例１、及び２）も、補色染料を含む比較例２のブラックインク組成物も、目視評価において少なくとも好ましい色相を有している。

As can be seen from Table 4, regarding the hue, both the black ink composition of the present invention (Examples 1 and 2) and the black ink composition of Comparative Example 2 containing a complementary color dye have at least a preferred hue in visual evaluation. ing.

[Clogging of black ink composition]
In order to accelerate the drying state with the nozzles with the ink cartridges mounted, after printing continuously for 10 minutes using the above ink cartridges and confirming that all the nozzles are ejected normally, the recording head Was removed from the head cap and left in an environment of 40 ° C. for 2 weeks. After leaving, the cleaning operation was repeated until all nozzles ejected at the same level as the initial stage. The ease of recovery was evaluated according to the following criteria, and the results are shown in Table 5.
A: It recovered to the same level as the initial stage after 1 to 3 cleaning operations.
B: Recovered to the initial level after 4 to 6 cleaning operations.
C: Recovered to the same level as the initial stage after 7 to 9 cleaning operations.
D: Recovered to the same level as the initial stage after 10 to 12 cleaning operations.

表５からわかるように、本発明のブラックインク組成物（実施例１及び２）の目詰まり性は、補色染料としてＣ．Ｉ．ダイレクトレッド８９を含有しない比較例２のブラックインク組成物に比べて良好である。
なお、比較例１の目詰まり性が、実施例１及び２より良好なのは、補色染料（マゼンタ染料１及びＣ．Ｉ．ダイレクトイエロー１７３）の固形分が含まれていないためであり、比較例２の諸特性が悪いのは補色染料（マゼンタ染料１及びＣ．Ｉ．ダイレクトイエロー１７３）の水溶性が低いことと、補色染料の発色性が悪い分、固形分も多くなっているためである。

As can be seen from Table 5, the clogging properties of the black ink compositions of the present invention (Examples 1 and 2) are C.I. I. It is better than the black ink composition of Comparative Example 2 that does not contain Direct Red 89.
The reason why the clogging property of Comparative Example 1 is better than that of Examples 1 and 2 is that the solid content of complementary color dyes (magenta dye 1 and CI direct yellow 173) is not included. These characteristics are poor because the complementary color dyes (magenta dye 1 and CI Direct Yellow 173) have low water solubility, and the color developability of the complementary color dye is poor and the solid content is also increased.

  As can be seen from the above Examples and Comparative Examples, as complementary color dyes for adjusting the hue added to the black dye 1, C.I. I. Direct Red 89 and C.I. I. Direct Yellow 86 and / or C.I. I. The black ink composition of the present invention using the direct yellow 132 (ink composition of the example) has at least C.I. as a complementary dye. I. The black ink composition to which direct red 89 is not added (the ink composition of the comparative example) is superior in terms of overall image storability, ink storability, hue, and clogging.

The black ink composition of the present invention has an excellent hue with respect to various media including plain paper, is less clogged, has good light resistance, ozone resistance, and excellent storage stability. Besides being useful when used in the ink jet recording method, it can also be used for general writing instruments, recorders, pen plotters, and the like.

Claims (15)

Water, a water-soluble organic solvent, and the following formula (1):

(In the formula (1), R ¹ represents a phenyl group having a substituent or a naphthyl group having a substituent, R ² represents a phenylene group having a substituent or a naphthylene group having a substituent, and R ³ is at least It represents a 5- to 7-membered heterocyclic group having one double bond and a substituent, and the substituent in R ^{1 to} R ³ is independently OH, SO ₃ H, PO ₃ H ₂ , CO ₂ H, NO ₂ , a C1-4 alkyl group, a substituted alkyl group, a C1-4 alkoxy group, a substituted alkoxy group, a substituted amino group, and a substituted phenyl group Selected from group.)
At least one black dye selected from the group consisting of a compound represented by formula (I) and a salt thereof, and at least C.I. I. A black aqueous ink composition comprising Direct Red 89, wherein the hue is adjusted by adding the complementary color dye.   As the complementary color dye, C.I. I. Direct Yellow 86 and / or C.I. I. The black aqueous ink composition according to claim 1, comprising Direct Yellow 132. The compound represented by the formula (1) is represented by the following formula (2):

(In the formula (2), R ^{1 to} R ⁹ independently represent a group selected from the group consisting of H, SO ₃ H, PO ₃ H ₂ , CO ₂ H and NO _2. )
The black aqueous ink composition according to claim 1, wherein the black aqueous ink composition is represented by the formula:   The black aqueous ink according to any one of claims 1 to 3, wherein the black dye is contained in an amount of 0.5 to 12.0% by weight based on the total weight of the black aqueous ink composition. Composition.   C. above. I. 5. The black aqueous ink according to claim 1, wherein the direct red 89 is contained in an amount of 0.02 to 3.5% by weight based on the total weight of the black aqueous ink composition. Composition.   C. I. Direct Yellow 86 and / or C.I. I. 6. The black aqueous ink according to claim 1, wherein the direct yellow 132 is contained in an amount of 0.02 to 2.5% by weight based on the total weight of the black aqueous ink composition. Composition.   The black dye and the C.I. I. The black aqueous ink composition according to any one of claims 1 to 6, comprising Direct Red 89 in a weight ratio of 15: 1 to 10: 4.   The black dye and the C.I. I. Direct Yellow 86 and / or C.I. I. The black aqueous ink composition according to any one of claims 1 to 7, which comprises direct yellow 132 in a weight ratio of 20: 1 to 10: 3.   The black aqueous ink composition according to claim 1, wherein the black ink composition contains a nonionic surfactant.   The black aqueous ink composition according to claim 9, wherein the nonionic surfactant is an acetylene glycol surfactant.   The black aqueous ink composition according to claim 9 or 10, comprising 0.1 to 5% by weight of the nonionic surfactant.   The black aqueous ink composition according to claim 1, wherein the black ink composition contains a penetration accelerator.   The black aqueous ink composition according to claim 12, wherein the penetration accelerator is a glycol ether.   An ink jet recording method comprising discharging the black aqueous ink composition according to any one of claims 1 to 13 as a droplet from a thin nozzle and attaching the droplet to a recording medium. A recorded matter printed by the inkjet recording method according to claim 14.