JP5807526B2 - Ink composition - Google Patents

Description

  The present invention relates to an ink composition, and more particularly, to an ink composition that can realize a recorded image having good light resistance without impairing the hue of a coloring material and ensures reliability as an ink.

  In recent years, it has been practiced to form a color image by an ink jet recording method using a plurality of color ink compositions to obtain a recorded matter. In general, a color image is formed by three colors, ie, a yellow ink composition, a magenta ink composition, and a cyan ink composition, and further, if desired, four colors including a black ink composition. In some cases, color images are formed with six colors obtained by adding a light cyan ink composition and a light magenta ink composition to these four colors, or seven colors obtained by further adding a dark yellow ink composition.

  In the ink composition used for forming the color image described above, the ink composition of each color itself has a good color developability, and a good intermediate color is obtained when a plurality of color ink compositions are combined. It is required that the color can be developed and that the obtained recorded matter does not discolor during storage.

  More recently, in “photographic image quality” printing by color inkjet printers, the head, ink composition, recording method, and media have been continuously improved, and the resulting image quality is comparable to “silver salt photography”. , "Like photo". On the other hand, with respect to the storability of the obtained image, the characteristics are improved by improving the ink composition and the media. In particular, the light resistance has been improved to a level where there is no practical problem (see Patent Documents 1 and 2), but it has not reached the same level as silver salt photographs. Regarding the evaluation of the light fastness, the determination is made using the fading rate of each of the pure color patterns (optical density near 1.0) of Y (yellow), M (magenta), and C (cyan) as an index. Is standard. Regarding the light fastness of the ink composition currently installed in the printer marketed on the market, when judged using the above evaluation method, the ability of the magenta ink composition is the lowest, and the light fastness of the ink set In many cases, it is rate-limiting. Therefore, improving the light resistance of the magenta ink composition is effective in improving the light resistance of photographic images and extending the light resistance life of the ink set.

  In addition, the printed matter created using the ink composition as described above is installed not only indoors but also outdoors, and may be exposed to sunlight as well as indoor light, and thus has excellent light resistance. There is a need to develop ink compositions.

  For example, as a colorant having excellent light resistance, a compound described in Patent Document 3 (azo dye) and a compound described in Patent Document 4 (anthrapyridone dye) have been proposed. A magenta ink composition having excellent light resistance using a combination of two types of colorants has also been proposed (see Patent Document 5).

JP 2000-290559 A JP 2001-288392 A JP 2002-371079 A JP 2002-332419 A JP 2005-105136 A

However, no ink composition has been known so far as far as the present inventors know about an ink composition that is excellent in storage stability and can realize a recorded image having good light resistance.
Accordingly, an object of the present invention is to provide an ink composition which is excellent in storage stability and can realize a recorded image having good light resistance. Means for solving the problems are as follows.

  (Application Example 1) An ink composition comprising an anthrapyridone dye represented by the following formula (I), disodium copper ethylenediaminetetraacetate (II), benzotriazole, and ammonia.

（式中、Ｍ¹は、水素原子、ＮＨ₄、またはＮａを表し、Ｒ¹は、水素原子、置換されてもよいアルキル基、置換されてもよいアリール基、または置換されてもよいベンゾイル基を表し、Ｒ²は、水素原子または置換されてもよいアルキル基を表し、Ｒ³は、水素原子、ハロゲン原子、または置換されてもよいアルキル基を表し、Ｒ⁴は、水素原子、置換されてもよいＮＨ₄、または置換されてもよいスルホン酸基を表し、Ｒ⁵はアシル基または下記式（II）を表す。）

(In the formula, M ¹ represents a hydrogen atom, NH ₄ , or Na, and R ¹ represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, or an optionally substituted benzoyl group. R ² represents a hydrogen atom or an optionally substituted alkyl group, R ³ represents a hydrogen atom, a halogen atom, or an optionally substituted alkyl group, R ⁴ represents a hydrogen atom, substituted NH ₄ which may be substituted, or a sulfonic acid group which may be substituted, and R ⁵ represents an acyl group or the following formula (II).

（式中、ＸおよびＹは、それぞれ独立して、塩素原子、水酸基、アミノ基、モノエタノールアミノ基、ジエタノールアミノ基、モルホリノ基、アニリノ基、フェノール基を表し、これらの基は、各々水素原子の部分が一種または二種以上の置換基により置換されていてもよい。）

(In the formula, X and Y each independently represent a chlorine atom, a hydroxyl group, an amino group, a monoethanolamino group, a diethanolamino group, a morpholino group, an anilino group, or a phenol group, and these groups each represent a hydrogen atom. May be substituted with one or more substituents.)

  (Application Example 2) The ink composition according to Application Example 1, wherein the anthrapyridone dye is a compound represented by the following formula (III).

（式中、Ｍ²は、水素原子、ＮＨ₄、またはＮａを表し、Ｒ⁶は、水素原子、置換されてもよいアルキル基、置換されてもよいアリール基、または置換されてもよいベンゾイル基を表し、Ｒ⁷は、水素原子または置換されてもよいアルキル基を表し、Ｒ⁸は、水素原子、ハロゲン原子、または置換されてもよいアルキル基を表し、Ｒ⁹は、水素原子、置換されてもよいＮＨ₄、または置換されてもよいスルホン酸基を表す。さらにＡは、アルキレン基、フェニレン基を含有するアルキレン基、または下記式（IV）で表される基を表す。さらにＺは、塩素原子、水酸基、アミノ基、モノエタノールアミノ基、ジエタノールアミノ基、モルホリノ基、アニリノ基、フェノール基を表し、これらの基は、各々水素原子の部分が一種または二種以上の置換基により置換されていてもよい。）

(In the formula, M ² represents a hydrogen atom, NH ₄ , or Na, and R ⁶ represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, or an optionally substituted benzoyl group. R ⁷ represents a hydrogen atom or an optionally substituted alkyl group, R ⁸ represents a hydrogen atom, a halogen atom, or an optionally substituted alkyl group, and R ⁹ represents a hydrogen atom or a substituted alkyl group. NH ₄ which may be substituted, or a sulfonic acid group which may be substituted, and A represents an alkylene group, an alkylene group containing a phenylene group, or a group represented by the following formula (IV), and Z represents Represents a chlorine atom, a hydroxyl group, an amino group, a monoethanolamino group, a diethanolamino group, a morpholino group, an anilino group or a phenol group, and these groups each have one or two or more substituted hydrogen atoms. It may be substituted by.)

（式中、Ｒ¹⁰は水素原子またはアルキル基を表す。）

(In the formula, R ¹⁰ represents a hydrogen atom or an alkyl group.)

  (Application Example 3) The ink composition according to Application Example 1 or 2, wherein the anthrapyridone dye is a compound represented by the following formula (V).

（式中、Ｍ³は、水素原子、ＮＨ₄、またはＮａを表し、Ｂはアルキレン基を表し、ｎは１または２を表す。）

(In the formula, M ³ represents a hydrogen atom, NH ₄ , or Na, B represents an alkylene group, and n represents 1 or 2.)

  (Application Example 4) The molar ratio between the ammonia content and the disodium ethylenediaminetetraacetate copper (II) content is in the range of 55: 1 to 550: 1, and the ammonia content. The ink composition according to any one of claims 1 to 3, wherein a molar ratio between the benzotriazole content and the benzotriazole content is in a range of 700: 1 to 7000: 1.

  The ink composition according to the present invention is an ink composition comprising an anthrapyridone dye represented by the above formula (I), disodium copper (II) ethylenediaminetetraacetate, benzotriazole, and ammonia. Hereinafter, the ink composition according to the present invention and each component contained in the ink composition will be described.

<Anthrapyridone dyes>
The ink composition of the present invention contains an anthrapyridone dye represented by the above formula (I).

As a preferred group of anthrapyridone dyes of the present invention, M ¹ represents NH ₄ or Na, and R ¹ may be substituted with a benzoyl group (preferably a sulfonic acid group (this sulfonic acid group is NH ₄ or Benzoyl group substituted with Na)), and R ² represents an optionally substituted alkyl group (preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group). , R ³ represents a hydrogen atom, R ⁴ represents a sulfonic acid group which may be substituted (preferably a sulfonic acid group substituted with NH ₄ or Na), and R ⁵ represents the above formula (II) (preferably In the formula (II), X and Y are each independently an amino group, an anilino group, a phenol group (more preferably, a carboxyl group (this carboxyl group may be substituted with NH ₄ or Na)) so Represents conversion phenol group), these groups are each part of the hydrogen atom is a group of compounds representative of the can) be substituted by one or more substituents.

According to a preferred embodiment of the present invention, the ink composition comprises an anthrapyridone dye obtained by mixing a compound in which M ¹ is NH ₄ and a compound in which M ¹ is Na in the above formula (I). Preferably, in the above formula (I), (compound in which M ¹ is NH ₄ ) :( compound in which M ¹ is Na) = anthrac mixed at a content ratio (molar ratio) of 6: 4 to 8: 2. More preferably, it is an ink composition containing a pyridone dye, and in the above formula (I), (compound in which M ¹ is NH ₄ ) :( compound in which M ¹ is Na) = 7: 3 content ratio It is even more preferable that the ink composition contains an anthrapyridone dye mixed in (molar ratio).

  A preferred embodiment of the anthrapyridone dye represented by the above formula (I) includes a compound represented by the following formula (III).

（式中、Ｍ²は、水素原子、ＮＨ₄、またはＮａを表し、Ｒ⁶は、水素原子、置換されてもよいアルキル基、置換されてもよいアリール基、または置換されてもよいベンゾイル基を表し、Ｒ⁷は、水素原子または置換されてもよいアルキル基を表し、Ｒ⁸は、水素原子、ハロゲン原子、または置換されてもよいアルキル基を表し、Ｒ⁹は、水素原子、置換されてもよいＮＨ₄、または置換されてもよいスルホン酸基を表し、さらにＡは、アルキレン基、フェニレン基を含有するアルキレン基、または下記式（IV）で表される基を表す。さらにＺは、塩素原子、水酸基、アミノ基、モノエタノールアミノ基、ジエタノールアミノ基、モルホリノ基、アニリノ基、フェノール基を表し、これらの基は、各々水素原子の部分が一種または二種以上の置換基により置換されていてもよい。）

(Wherein, M ² represents a hydrogen atom, NH _4, or Na,, R ⁶ is a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group or an optionally substituted benzoyl group, R ⁷ represents a hydrogen atom or an optionally substituted alkyl group, R ⁸ represents a hydrogen atom, a halogen atom, or an optionally substituted alkyl group, and R ⁹ represents a hydrogen atom or a substituted alkyl group. NH ₄ which may be substituted, or an optionally substituted sulfonic acid group, and A represents an alkylene group, an alkylene group containing a phenylene group, or a group represented by the following formula (IV), and Z represents Represents a chlorine atom, a hydroxyl group, an amino group, a monoethanolamino group, a diethanolamino group, a morpholino group, an anilino group or a phenol group, and these groups each have one or two or more substituted hydrogen atoms. It may be substituted by.)

（Ｒ¹⁰は水素原子またはアルキル基を表す。）

(R ¹⁰ represents a hydrogen atom or an alkyl group.)

As a preferred group of anthrapyridone dyes of the present invention, M ² represents NH ₄ or Na, and R ⁶ may be substituted with a benzoyl group (preferably a sulfonic acid group (this sulfonic acid group is NH ₄ or Benzoyl group substituted with Na), and R ⁷ represents an optionally substituted alkyl group (preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group). , R ⁸ represents a hydrogen atom, and R ⁹ may be substituted with a sulfonic acid group (preferably a sulfonic acid group substituted with NH ₄ or Na), and A is an alkylene group or the above formula (IV) (preferably , R ¹⁰ represents a hydrogen atom) represents, Z is an amino group or a phenol group (more favorable details, carboxyl group (carboxyl group may be substituted with NH ₄ or Na) is substituted with A group of compounds representative of the phenol group).

According to a preferred embodiment of the present invention, the ink composition preferably includes an anthrapyridone dye in which a compound in which M ² is NH ₄ and a compound in which M ² is Na in the formula (III) is mixed. In the above formula (III), (a compound in which M ² is NH ₄ ) :( a compound in which M ² is Na) = Anthrapyridone mixed at a content ratio (molar ratio) of 6: 4 to 8: 2 It is more preferable that the ink composition contains a dye. In the formula (III), the content ratio of (a compound in which M ² is NH ₄ ) :( a compound in which M ² is Na) = 7: 3 ( It is even more preferable that the ink composition contains an anthrapyridone dye mixed in a molar ratio.

  A more preferred embodiment of the anthrapyridone dye represented by the above formula (I) or (III) includes a compound represented by the following formula (V).

（式中、Ｍ³は、水素原子、ＮＨ₄、またはＮａを表し、Ｂはアルキレン基を表し、ｎは１または２を表す。）

(In the formula, M ³ represents a hydrogen atom, NH ₄ , or Na, B represents an alkylene group, and n represents 1 or 2.)

The compound group of the preferred anthrapyridone dye of the present invention includes a compound group in which M ³ represents NH ₄ or Na, B represents an alkylene group (preferably an ethylene group), and n = 2.

According to a preferred embodiment of the present invention, the ink composition preferably includes an anthrapyridone dye in which a compound in which M ³ is NH ₄ and a compound in which M ³ is Na in the formula (V) is mixed. In the above formula (V), (a compound in which M ³ is NH ₄ ) :( a compound in which M ³ is Na) = Anthrapyridone mixed at a content ratio (molar ratio) of 6: 4 to 8: 2 It is more preferable that the ink composition contains a dye. In the above formula (V), the content ratio (compound in which M ³ is NH ₄ ) :( compound in which M ³ is Na) = 7: 3 ( It is even more preferable that the ink composition contains an anthrapyridone dye mixed in a molar ratio.

  Moreover, the compound represented by following formula (VI) is mentioned as a still more preferable aspect of the anthrapyridone type dye represented by the said formula (III).

（式中、Ｍ⁴が、水素原子、ＮＨ₄、またはＮａを表す。）

(In the formula, M ⁴ represents a hydrogen atom, NH ₄ , or Na.)

Further, according to a preferred embodiment of the anthrapyridone dye represented by the above formula (VI), an anthra obtained by mixing a compound in which M ⁴ is NH ₄ and a compound in which M ⁴ is Na in the above formula (VI). An ink composition containing a pyridone dye is preferable. In the above formula (VI), (a compound in which M ⁴ is NH ₄ ) :( a compound in which M ⁴ is Na) = 6: 4 to 8: 2 More preferably, the ink composition contains an anthrapyridone dye mixed at a content ratio (molar ratio). In the above formula (VI), (a compound in which M ⁴ is NH ₄ ): (M ⁴ is Na It is even more preferable that the ink composition includes an anthrapyridone dye mixed at a content ratio (molar ratio) of 7: 3.

  Moreover, the compound represented by following formula (VII) is mentioned as a still more preferable aspect of the anthrapyridone type dye represented by the said formula (V).

（式中、Ｍ⁵が、水素原子、ＮＨ₄、またはＮａを表す。）

(In the formula, M ⁵ represents a hydrogen atom, NH ₄ or Na.)

Furthermore, according to a preferred embodiment of the anthrapyridone dye represented by the formula (VII), an anthra obtained by mixing a compound in which M ⁵ is NH ₄ and a compound in which M ⁵ is Na in the formula (VII). An ink composition containing a pyridone dye is preferable. In the above formula (VII), (a compound in which M ⁵ is NH ₄ ) :( a compound in which M ⁵ is Na) = 6: 4 to 8: 2 More preferably, the ink composition contains an anthrapyridone dye mixed at a content ratio (molar ratio). In the above formula (VI), (a compound in which M ⁵ is NH ₄ ): (M ⁵ is Na It is even more preferable that the ink composition includes an anthrapyridone dye mixed at a content ratio (molar ratio) of 7: 3.

  The content of the anthrapyridone dye is not particularly limited as long as a recording image having good light resistance can be realized without impairing the hue of the coloring material, but preferably 1 to 10 mass with respect to the ink composition. %, More preferably in the range of 5 to 8% by mass. By setting it within this range, it is possible to realize a recorded image having both color developability and light fastness.

  The content of the above-mentioned anthrapyridone dye contained in the ink composition of the present invention is not particularly limited as long as a recorded image having good light resistance can be realized without impairing the hue of the coloring material, but preferably The ratio of the content of the anthrapyridone dye and the content of the following water-soluble copper compound is in the range of 1: 1 to 100: 1, more preferably 2: 1 to 80. : 1 and more preferably within the range of 3: 1 to 32: 1. By setting it in this range, a recorded image having good light resistance can be realized without impairing the hue of the color material.

<Ethylenediaminetetraacetic acid disodium copper II>
The ink composition of the present invention contains ethylenediaminetetraacetic acid disodium copper (II). Since this compound has an extremely high chelating ability of copper compared to other copper compounds, foreign matters derived from copper can be suppressed to a minimum, harmful effects such as clogging can be prevented, and excellent print quality can be ensured. By including this compound in the ink composition of the present invention, it is possible to realize a recorded image having good light resistance without impairing the hue of the coloring material, and preventing bad effects such as clogging, and excellent print quality. Can be secured.

  In the present invention, the content of ethylenediaminetetraacetic acid disodium copper (II) contained in the ink composition is preferably 0.05 to 5% by mass relative to the ink composition. More preferably, 4% by mass is contained. By setting it in this range, a recorded image having good light resistance can be realized without impairing the hue of the color material.

<Ammonia>
The ink composition of the present invention contains ammonia as a foreign matter inhibitor. Ammonia inhibits the reaction between disodium copper (II) ethylenediaminetetraacetate and the rust inhibitor benzo and riazole, suppresses the generation of foreign matter, prevents clogging and other harmful effects, and provides excellent print quality. It can be secured.

  In the present invention, the molar ratio between the content of ammonia contained in the ink composition and the content of ethylenediaminetetraacetic acid disodium copper (II) is in the range of 55: 1 to 550: 1, and The molar ratio between the ammonia and the benzotriazole content is in the range of 700: 1 to 7000: 1. By setting it within this range, it is possible to suppress the generation of foreign matters, prevent harmful effects such as clogging, and ensure excellent print quality.

<Water, water-soluble organic solvent, and other optional components>
The ink composition according to the present invention contains an anthrapyridone dye represented by the above formula (I) in an aqueous medium consisting of only water or water and a water-soluble organic solvent, and if necessary, a humectant, A surfactant, a penetration accelerator, a viscosity modifier, a pH adjuster, and other additives may be contained.

  The ink composition in the present invention can be obtained by dissolving the above-described anthrapyridone dye in a suitable solvent. As a solvent for dissolving the coloring material in the ink composition, water or a mixed liquid of water and a water-soluble organic solvent is preferably used as a main solvent. As water, ion exchange water, ultrafiltration water, reverse osmosis water, distilled water, or the like can be used. From the viewpoint of long-term storage, it is preferable to use water that has been subjected to various chemical sterilization treatments such as ultraviolet irradiation and addition of hydrogen peroxide. The water content in the ink composition of the present invention is preferably 40 to 90% by mass of the ink composition, and more preferably 50 to 80% by mass.

  As described above, the ink composition in the present invention can use a water-soluble organic solvent as a solvent together with water. As the water-soluble organic solvent, those having the ability to dissolve the dye are preferable, and those having a vapor pressure smaller than that of pure water are preferable.

  Examples of the water-soluble organic solvent used in the present invention include ethylene glycol, propylene glycol, butanediol, pentanediol, 2-butene-1,4-diol, 2-methyl-2,4-pentanediol, glycerin, 1, Polyhydric alcohols such as 2,6-hexanetriol, diethylene glycol, triethylene glycol and dipropylene glycol, ketones such as acetonylacetone, esters such as γ-butyrolactone and triethyl phosphate, furfuryl alcohol, tetrahydrofurfuryl Although alcohol, thiodiglycol, etc. are preferable, it is not limited to these. By using a water-soluble organic solvent together with water as the solvent of the ink composition, the ejection stability of the ink composition from the ink head can be improved, and the viscosity of the ink composition can be lowered with almost no other change. Etc. can be easily adjusted.

  Further, a saccharide can be contained in the ink composition of the present invention as a humectant. The ink can be moisturized by including a saccharide in the ink composition. As the saccharide used in the present invention, maltitol, sorbitol, gluconolactone, maltose and the like are preferable. In addition, the water-soluble organic solvent mentioned above may work as a moisturizer.

  The water-soluble organic solvent and / or humectant can be contained in the ink composition in a total amount of 5 to 50% by mass, more preferably 5 to 30% by mass, and particularly preferably 5 to 20% by mass. By making these contents 5% by mass or more, good ink moisture retention can be obtained, and by making it 50% by mass or less, the viscosity of the ink composition is adjusted to a preferred viscosity for use in the ink jet recording method. can do.

  The surfactant contained in the ink composition of the present invention is not particularly limited, but a nonionic surfactant is preferable. By adding a nonionic surfactant to the ink composition, the ink composition has excellent permeability to the recording medium, and the ink composition can be quickly fixed on the recording medium during printing. Further, it is preferable that one dot recorded by the ink composition on the recording medium is as close to a perfect circle as possible, but an image formed by one dot by incorporating a nonionic surfactant in the ink composition. The roundness of the image can be increased, and the image quality of the obtained image can be improved.

Examples of nonionic surfactants that can be used in the present invention include acetylene glycol surfactants. Specific examples of acetylene glycol surfactants include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl-1-hexyn-3-ol, 2,4-dimethyl-5-hexyn-3-ol and the like can be mentioned. The addition amount is preferably 0.1 to 5% by mass, more preferably 0.5 to 3% by mass. When the addition amount is 0.1% by mass or more, sufficient permeability can be obtained, and when the addition amount is 5% by mass or less, it is easy to prevent the occurrence of image blur.
Commercially available products can be used as the above-mentioned surfactants. For example, Surfynol 61, 82, 104, 440, 465, 485 (all are trade names, Air Products) -And Chemicals Co., Ltd.), Orphine E1010, Orphine PD001, Orphine STG (above, Nissin Chemical Industry Co., Ltd., trade name) can be used.

  Furthermore, in addition to nonionic surfactants, the addition of glycol ethers as penetration enhancers to the ink composition improves the penetrability of the ink composition with respect to the recording medium, and when color printing is performed. At the boundary between adjacent color inks, ink bleeding (bleeding) is reduced, and a very clear image can be obtained. Therefore, it is preferable to add a penetration enhancer to the ink composition of the present invention.

  The glycol ethers used in the present invention as penetration enhancers 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, dipropylene Glycol monobutyl ether, triethylene glycol monobutyl ether and the like are preferable, but are not limited thereto. These glycol ethers are preferably contained in the ink composition in an amount of 3 to 30% by mass, more preferably 5 to 15% by mass. By making the addition amount of glycol ethers 3% by mass or more, bleeding (bleeding) between adjacent inks at the time of color printing can be effectively prevented, and further by making this addition amount 30% by mass or less, image It becomes easy to prevent the occurrence of bleeding, and the storage stability of the ink can be improved.

  Further, the ink composition of the present invention includes a pH adjuster such as triethanolamine or alkali metal hydroxide, a water-soluble polymer such as sodium alginate, a water-soluble resin, a fluorosurfactant, an antiseptic, and an antifungal agent. A material selected from a rust inhibitor, a dissolution aid, an antioxidant, an ultraviolet absorber, and the like can be added as desired. These components can be used alone or in combination of two or more. Moreover, it is not necessary to add, if it is not necessary to add. 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 dissolution aid is an additive for dissolving the insoluble matter and keeping the ink composition in a uniform solution when the insoluble matter is precipitated from the ink composition.

  Examples of the solubilizer include pyrrolidones such as N-methyl-2-pyrrolidone and 2-pyrrolidone, ureas such as urea, thiourea and tetramethylurea, allophanates such as allohanate and methyl allophanate, biuret and dimethylbiuret. And biurets such as tetramethylbiuret can be mentioned, but the invention is not limited to these. Examples of the antioxidant include L-ascorbic acid and salts thereof, but are not limited thereto.

  Examples of the antiseptic or antifungal agent include sodium benzoate, sodium pentachlorophenol, 2-pyridinethiol-1-oxide sodium, sodium sorbate, sodium dehydroacetate, and 1,2-dibenzisothiazoline-3. -ON (Avexia Proxel CRL, Proxel BDN, Proxel GXL, Proxel XL-2, Proxel TN (trade name) and the like can be exemplified, but not limited thereto.

  Examples of the pH adjuster include amines such as diethanolamine, triethanolamine, propanolamine, and morpholine, and modified products thereof, metal hydroxides such as potassium hydroxide, sodium hydroxide, and lithium hydroxide, ammonium hydroxide, Examples thereof include ammonium salts such as quaternary ammonium hydroxide (tetramethylammonium, etc.), carbonates such as potassium carbonate, sodium carbonate, lithium carbonate, and other phosphates, but are not limited thereto.

  The ink composition of the present invention is prepared by including components appropriately selected from the components described above, and the viscosity of the obtained ink composition is preferably less than 10 mPa · s at 20 ° C. Furthermore, in the present invention, the surface tension of the ink composition is preferably 45 mN / m or less at 20 ° C., and particularly preferably in the range of 25 to 45 mN / m. By adjusting the viscosity and the surface tension in this way, an ink composition having desirable characteristics for use in the ink jet recording method can be obtained. The adjustment of the viscosity and the surface tension can be performed by appropriately adjusting and selecting the addition amount of the solvent and various additives to be contained in the ink composition, the kind thereof, and the like.

  As a method for preparing the ink composition in the present invention, for example, various components contained in the ink composition are sufficiently mixed and dissolved as uniformly as possible, and then subjected to pressure filtration with a membrane filter having a pore size of 0.8 μm. Although the method of preparing the obtained solution by deaerating using a vacuum pump can be illustrated, it is not limited to this.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by these Examples.

<Preparation of ink composition>
The ink composition having the composition shown in Table 1 below was stirred at room temperature for 1 hour, and then filtered through a 0.8 μm membrane filter to obtain each ink composition. In addition, the numerical value in following Table 1 represents content (mass%) in an ink. In addition, compounds A, B, and C in Table 1 are compounds represented by the following formulas, respectively, and in the following formula, a compound in which M = NH ₄ and a compound in which M = Na are 7: 3 is mixed at a ratio (molar ratio) of 3.

  These ink compositions were evaluated as follows. The results are shown in Table 2.

(Storage stability evaluation)
The ink composition (ink compositions of Examples 1 to 12) was degassed under reduced pressure with a vacuum pump, then packed in an ink pack, and left in an environment of 70 ° C. for 6 days. The “ink compositions to which ammonia was added” in Examples 1 to 6, 7 and 8 were added after degassing under reduced pressure so that the ammonia content in the ink composition was not reduced by degassing under reduced pressure. After standing at high temperature, 10 ml of the ink composition in the pack was filtered with a 10 μm metal filter. The storage stability was evaluated according to the following criteria based on the amount of foreign matter collected on the metal filter and the state of filtration.
A: No foreign matter is collected by filtration.
B: Some foreign matter was collected, but 10 ml of ink could be filtered.
C: Some foreign matter was collected, but 10 ml of ink could be filtered.
D: Although considerable foreign matter is collected by filtration, 10 ml of ink can be filtered.
E: Foreign matter was piled up and clogged, and 10 ml of ink could not be filtered.

(Light resistance evaluation)
(1) Preparation of Evaluation Sample The ink composition obtained as described above was filled in the ink chamber of a dedicated cartridge of an inkjet printer (trade name “PM-A700”, manufactured by Seiko Epson Corporation). Then, an ink cartridge was mounted on the printer, and a solid pattern image was recorded on photographic paper Crispier (registered trademark) (trade name, model number “KA450SCKR”, manufactured by Seiko Epson Corporation) to obtain an evaluation sample. The solid pattern image was recorded by adjusting the duty so that the obtained image had an OD (Optical Density) of 1.0.

(2) Light resistance evaluation test The evaluation sample obtained as described above was allowed to stand in a dark place at room temperature for 1 day. After that, the evaluation sample was installed in a Xenon light resistance tester XL-75s (trade name: manufactured by Suga Test Instruments Co., Ltd.), and a 14-day exposure test was performed under conditions of 23 ° C. relative humidity 50% RH and illuminance 75000 lux. It was.

  Then, using a spectrophotometer Spectrolino (trade name, manufactured by GretagMacbeth), the OD value before and after light irradiation of the image recorded on the sample was measured. The OD value was measured at a viewing angle of 2 ° with a light source of D50, no light source filter, and absolute white as a white standard.

  The light resistance was evaluated by obtaining the optical density residual ratio (ROD) of the image of each recorded matter after light irradiation from the obtained measured value (OD value). The calculation method of ROD is “ROD (%) = (Dn / Do) × 100 (where Dn is the OD value of the image after the end of the light irradiation test, and Do is the OD value of the image before the start of the light irradiation test)”. It is. A higher ROD value indicates less degradation of the image due to light irradiation.

  The evaluation criteria for light resistance are as follows. If the evaluation criteria are “A” and “B”, it can be determined that the light resistance is practically usable. The evaluation results are also shown in Table 30.

“A”: ROD is 90% or more.
“B”: ROD is 75% or more and less than 90%.
“C”: ROD is 60% or more and less than 75%.
“D”: ROD is less than 60%.

Claims (4)

An anthrapyridone dye represented by the following formula (I):
Ethylenediaminetetraacetic acid disodium copper (II),
Benzotriazole,
An ink composition comprising ammonia.

(In the formula, M ¹ represents a hydrogen atom, NH ₄ , or Na, and R ¹ represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, or an optionally substituted benzoyl group. R ² represents a hydrogen atom or an optionally substituted alkyl group, R ³ represents a hydrogen atom, a halogen atom, or an optionally substituted alkyl group, R ⁴ represents a hydrogen atom, substituted NH ₄ which may be substituted, or a sulfonic acid group which may be substituted, and R ⁵ represents an acyl group or the following formula (II).

(In the formula, X and Y each independently represent a chlorine atom, a hydroxyl group, an amino group, a monoethanolamino group, a diethanolamino group, a morpholino group, an anilino group, or a phenol group, and these groups each represent a hydrogen atom. May be substituted with one or more substituents.) The ink composition according to claim 1, wherein the anthrapyridone dye is a compound represented by the following formula (III).

(In the formula, M ² represents a hydrogen atom, NH ₄ , or Na, and R ⁶ represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, or an optionally substituted benzoyl group. R ⁷ represents a hydrogen atom or an optionally substituted alkyl group, R ⁸ represents a hydrogen atom, a halogen atom, or an optionally substituted alkyl group, and R ⁹ represents a hydrogen atom or a substituted alkyl group. NH ₄ which may be substituted, or a sulfonic acid group which may be substituted, and A represents an alkylene group, an alkylene group containing a phenylene group, or a group represented by the following formula (IV), and Z represents Represents a chlorine atom, a hydroxyl group, an amino group, a monoethanolamino group, a diethanolamino group, a morpholino group, an anilino group or a phenol group, and these groups each have one or two or more substituted hydrogen atoms. It may be substituted by.)

(In the formula, R ¹⁰ represents a hydrogen atom or an alkyl group.) The ink composition according to claim 1 or 2, wherein the anthrapyridone dye is a compound represented by the following formula (V):

(In the formula, M ³ represents a hydrogen atom, NH ₄ , or Na, B represents an alkylene group, and n represents 1 or 2.)   The molar ratio of the ammonia content to the ethylenediaminetetraacetic acid disodium copper (II) content is in the range of 55: 1 to 550: 1, and the ammonia content and the benzotriazole The ink composition according to any one of claims 1 to 3, wherein the molar ratio with the content of is in the range of 700: 1 to 7000: 1.