ink

Abstract

To provide an ink that enables the production of printed materials that possess good color hues and excellent ozone resistance. [Solution] An ink comprising dye A represented by the following formula (1), dye B selected from CI Direct Yellow, dye C selected from CI Acid Red, and water, wherein when the total mass percentage of dye B is b and the total mass percentage of dye C is c, the value obtained by b / c is greater than 0.7 and less than 5.5. TIFF2026166548000006.tif40170 [In the formula, R1, R2, R5, R6, and R7 independently represent groups selected from hydrogen atoms, halogen atoms, cyano groups, hydroxyl groups, carboxyl groups, sulfo groups, sulfamoyl groups, nitro groups, etc. R3 and R4 independently represent groups selected from hydrogen atoms, halogen atoms, cyano groups, sulfo groups, carboxyl groups, etc. n represents 0 or 1.]

Description

Technical Field

[0001] The present invention relates to an ink.

Background Art

[0002] The inkjet recording method is a recording method that forms an image by applying fine ink droplets onto a recording medium such as plain paper or photographic glossy paper, and has been rapidly spreading due to reduced costs and improved recording speeds. In addition to the progress in higher image quality of images obtained by the inkjet recording method, along with the rapid spread of digital cameras, the inkjet recording method is required to have color developability and durability equivalent to those of silver halide photographs.

[0003] However, recorded matter obtained by the inkjet recording method tends to have lower ozone resistance and light resistance compared to silver halide photographs. Specifically, when the recorded matter is exposed for a long time to light, humidity, heat, ozone gas present in the air, and the like, the dye on the recorded matter deteriorates, which easily causes hue change and fading of the image.

[0004] In photographic image quality printing, it is desired that the recorded image of the ink has high density and is clear. In addition, the ink is required to be stable during long-term storage and to have excellent fastness properties such as light resistance, ozone resistance, and moisture resistance. Furthermore, attempts to improve the ozone resistance of the ink may cause a bronze phenomenon, and it is also necessary to reduce such a bronze phenomenon. The bronze phenomenon refers to a reddish floating phenomenon observed in a printed portion when printing is performed at a high density, and tends to easily occur when performing solid printing (fill printing at 100% output) or the like. Since the bronze phenomenon disturbs the color balance of the entire image and degrades image quality, it is required to achieve both fastness properties such as light resistance, ozone resistance, and moisture resistance, and anti-bronze properties.

[0005] Black ink is an essential ink used in both monochrome and full-color images. However, developing a pigment that is neutral in both the dark and light color gamuts, has high image density, and exhibits excellent fastness is technically challenging. Despite extensive research and development, few pigments still possess sufficient performance. Therefore, black ink is generally prepared by mixing multiple diverse pigments. However, when preparing ink by mixing multiple pigments, problems such as greater discoloration are more likely to occur compared to preparing ink with a single pigment. If the ozone resistance of a particular pigment is significantly lower than that of other pigments used for color mixing, that pigment will fade and discolor faster than the others, resulting in an imbalance in the overall color tone of the image. In this case, the observer will be able to perceive the deterioration of image quality in a shorter time than they would be able to perceive the fading of an image formed with a single ink. Therefore, in black ink, it is necessary to improve the fastness of each constituent pigment, such as ozone resistance and lightfastness, and to make the rate of discoloration and fading due to ozone or light as uniform as possible. In other words, it is desirable that the fastness of each pigment constituting black ink is excellent, and that the difference in fastness between each pigment is small.

[0006] As an example of a black ink in which a color-matching dye is further blended with a black dye, Patent Document 1 is provided. While proposals have been made, they have not yet resulted in a product that fully satisfies market demands.

[0007] Furthermore, dyes represented by the following formula (1) described herein are described in Patent Documents 2 to 5. However, these do not fully satisfy the above-mentioned problems in terms of hue and ozone resistance. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 7-97541 [Patent Document 2] International Publication No. 2006 / 051850 [Patent Document 3] International Publication No. 2013 / 035560 [Patent Document 4] Japanese Patent Publication No. 2008-69331 [Patent Document 5] Japanese Patent Publication No. 2013-32469 [Overview of the project] [Problems that the invention aims to solve]

[0009] This invention has been made in view of the above circumstances, and aims to provide an ink that enables the provision of printed materials having good hue and excellent ozone resistance. [Means for solving the problem]

[0010] The inventors of this invention conducted extensive research to solve the above-mentioned problems and, as a result, discovered that a specific ink can solve the above-mentioned problems, thus completing the present invention.

[0011] In other words, the present invention relates to the following 1) to 9). 1) An ink comprising dye A represented by the following formula (1), dye B selected from CI Direct Yellow, dye C selected from CI Acid Red, and water, wherein when the total mass percentage of dye B is b and the total mass percentage of dye C is c, the value obtained by b / c is greater than 0.7 and less than 5.5.

[0012] [ka]

[0013] [In formula (1), R1, R2, R5, R6 and R7 each independently represent a group selected from the group consisting of a hydrogen atom, a halogen atom, a cyano group, a hydroxy group, a carboxy group, a sulfo group, a sulfamoyl group, a nitro group, an optionally substituted alkoxy group, an optionally substituted alkylsulfonyl group, an alkyl group, an optionally substituted arylsulfamoylamino group, and an alkylcarbonylamino group. R3 and R4 each independently represent a group selected from the group consisting of a hydrogen atom, a halogen atom, a cyano group, a sulfo group, a carboxy group, a nitro group, an optionally substituted alkoxy group, and an alkyl group. n represents 0 or 1.] 2) The ink according to 1), which has a viscosity of 3.0 to 13.0 mPa·s at 25°C and a static surface tension of 32 to 42 mN / m at 25°C. 3) The ink according to 1) or 2), further containing a surfactant in an amount of 0.05% by mass to 4% by mass relative to the total mass of the ink. 4) The ink according to any one of 1) to 3), wherein the surfactant contains at least an acetylene glycol-based surfactant. 5) The ink according to any one of 1) to 4), wherein in formula (1), R1 is a carboxy group or a sulfo group, R2 is a hydrogen atom, R6 is a nitro group, a carboxy group, or a sulfo group, and n is 1. 6) The ink according to any one of 1) to 5), wherein in formula (1), R1 and R3 are sulfo groups, R4 is a hydrogen atom, R5 is a hydrogen atom, a carboxy group, or a sulfo group, R6 is a nitro group, a carboxy group, or a sulfo group, R7 is a hydrogen atom, and n is 1. 7) An ink set comprising the ink according to any one of 1) to 6) and another ink. 8) An inkjet recording method for performing recording by ejecting droplets of the ink according to any one of 1) to 6) from an inkjet head and attaching the droplets to a recording medium. 9) An inkjet recording method for performing recording by ejecting droplets of any one of the inks constituting the ink set described in 7) from an inkjet head and causing the droplets to adhere to a recording medium.

Effects of the Invention

[0014] According to the present invention, it is possible to provide an ink that enables provision of printed matter having a good hue and also exhibiting the effect of excellent ozone resistance.

Modes for Carrying Out the Invention

[0015] The present invention is described in detail below. In the present specification, unless otherwise specified, "part" and "%" including those in Examples and the like are all described on a mass basis. In addition, "C.I." represents the abbreviation of Color Index.

[0016] The ink contains Dye A represented by the above formula (1), Dye B selected from C.I. Direct Yellows, Dye C selected from C.I. Acid Reds, and water, and when the total content mass% of the Dye B is defined as b and the total content mass% of the Dye C is defined as c, the value determined by b / c is in the range of more than 0.7 and less than 5.5.

[0017] [Dye A] The Dye A is not particularly limited as long as it is represented by the above formula (1). In formula (1), R1, R2, R5, R6, and R7 each independently represent a group selected from the group consisting of a hydrogen atom, a halogen atom, a cyano group, a hydroxyl group, a carboxyl group, a sulfo group, a sulfamoyl group, a nitro group, an optionally substituted alkoxy group, an optionally substituted alkylsulfonyl group, an alkyl group, an optionally substituted arylsulfamoylamino group, and an alkylcarbonylamino group. R3 and R4 each independently represent a group selected from the group consisting of a hydrogen atom, a halogen atom, a cyano group, a sulfo group, a carboxyl group, a nitro group, an optionally substituted alkoxy group, and an alkyl group. n represents 0 or 1. The substituents of the compound represented by formula (1) above, specific examples of the compound, and methods of production may be the same as those disclosed in Japanese Patent No. 6506441. Preferred examples of the compound represented by formula (1) above may also be the same as those disclosed in Japanese Patent No. 6506441. Preferred compounds are those in which R1 is a carboxyl group or a sulfo group, R2 is a hydrogen atom, R6 is a nitro group, a carboxyl group, or a sulfo group, and n is 1. Preferred compounds are those in which R1 and R3 are sulfo groups, R4 is a hydrogen atom, R5 is a hydrogen atom, a carboxyl group, or a sulfo group, R6 is a nitro group, a carboxyl group, or a sulfo group, R7 is a hydrogen atom, and n is 1. The compound of formula (22) in Japanese Patent No. 6506441 is particularly preferred.

[0018] The content of the dye represented by formula (1) above is usually 2.0 to 5.0% by mass, preferably 2.2 to 4.7% by mass, more preferably 2.3 to 4.3% by mass, and even more preferably 2.4 to 3.8% by mass, relative to the total mass of the ink, in order to obtain an appropriate image density and prevent dye deposition.

[0019] [Dye B] The dye B mentioned above is not particularly limited as long as it is a dye selected from CI Direct Yellow. Specific examples of dye B include, for example, CI Direct Yellow 8, 11, 12, 21, 24, 26, 28, 33, 39, 44, 49, 50, 85, 86, 87, 88, 89, 98, 100, 110, 132, 142, 144, 146, etc., with CI Direct Yellow 50, 86, 132, and 142 being preferred, and CI Direct Yellow 86, 132, and 142 being more preferred. Furthermore, dye B may consist of one or more dyes selected from CI Direct Yellow.

[0020] The content of dye B is preferably 0.4 to 3.0% by mass, more preferably 0.6 to 2.5% by mass, even more preferably 0.8 to 2.0% by mass, and particularly preferably 0.9 to 1.8% by mass, relative to the total mass of the ink, in order to obtain an appropriate image density and to prevent the deposition of dye B. By limiting the CI Direct Yellow content to 3.0% by mass or less relative to the total mass of the ink, dye precipitation tends to be suppressed under storage conditions of -5°C or below.

[0021] [Dye C] The above dye C is not particularly limited as long as it is a dye selected from CI Acid Red. Specific examples of the above dye C include, for example, CI Acid Red 1, 6, 8, 9, 13, 18, 27, 32, 35, 37, 51, 52, 54, 57, 73, 80, 82, 85, 87, 88, 92, 94, 97, 97:1, 106, 111, 114, 115, 118, 119, 127, 131, 138, 143, 145, 151, 181, 183, 195, 198, 211, 215, 21 Examples include 7, 225, 226, 249, 251, 254, 256, 257, 260, 261, 264, 265, 266, 274, 276, 277, 289, 296, 299, 315, 317, 318, 336, 337, 357, 359, 361, 362, 364, 366, 399, 407, 415, etc., and it is preferable that it be CI Acid Red 249, 254, etc., and more preferably CI Acid Red 249. Furthermore, the above dye C consists of one or more dyes selected from CI Acid Red.

[0022] The content of dye C in the ink is preferably 0.1 to 3.0% by mass, more preferably 0.3 to 2.5% by mass, even more preferably 0.4 to 2.0% by mass, and particularly preferably 0.5 to 1.5% by mass, relative to the total mass of the ink, in order to obtain an appropriate image density and to prevent the deposition of dye C. By limiting the CI Acid Red content to 3.0% by mass or less relative to the total mass of the ink, dye precipitation tends to be suppressed under storage conditions of -5°C or below.

[0023] In the above ink, if b is the total mass percentage of dye B and c is the total mass percentage of dye C, the value obtained by b / c is preferably greater than 0.9 and 5.0 or less, more preferably between 1.0 and 4.0, and even more preferably between 1.2 and 3.0.

[0024] The above ink contains water. Preferably, the water is low in impurities such as metal ions, i.e., ion-exchanged water or distilled water. Such water can be prepared by known methods. The water content in the above ink is not particularly limited and can be determined as needed, but in order to adjust the viscosity of the ink to a suitable range, it is usually 30% to 60% by mass, preferably 35% to 57% by mass, more preferably 38% to 55% by mass, and even more preferably 40% to 53% by mass, based on the total mass (100% by mass) of the ink.

[0025] The above ink may further contain a dye for toning to achieve a desired hue. From the viewpoint of adhesion to the recording material, reactive dyes, acid dyes, or direct dyes are preferred as the dye for toning, with acid dyes and direct dyes being more preferred.

[0026] Specific examples of acid dyes used for color mixing include, for example, CI Acid Yellow 1, 3, 11, 17, 18, 19, 23, 25, 36, 38, 40, 40:1, 42, 44, 49, 59, 59:1, 61, 65, 72, 73, 79, 99, 104, 110, 159, 169, 176, 184, 193, 200, 204, 207, 215, 219, 219:1, 220, 230, 232, 235, 241, 242, 246, and other yellow dyes; CI Acid Orange Orange dyes such as 3, 7, 8, 10, 19, 24, 51, 56, 67, 74, 80, 86, 87, 88, 89, 94, 95, 107, 108, 116, 122, 127, 140, 142, 144, 149, 152, 156, 162, 166, 168, etc.; CI Acid Brown; Brown dyes such as 2, 4, 13, 14, 19, 28, 44, 123, 224, 226, 227, 248, 282, 283, 289, 294, 297, 298, 301, 355, 357, 413, etc.; CI Acid Blue Examples include blue dyes such as 9, 22, 40, 59, 93, 102, 104, 113, 117, 120, 167, 229, 234, and 249; violet dyes such as CI Acid Violet 49; and black dyes such as CI Acid Black 2, 7, 24, 26, 31, 52, 63, 112, and 118.

[0027] Specific examples of direct dyes for color mixing include, for example, orange dyes such as CI Direct Orange 17, 26, 34, 39, 44, 46, 60, 102; brown dyes such as CI Direct Brown 109; and CI Direct Red Red dyes such as 2, 4, 6, 9, 17, 23, 26, 28, 31, 39, 54, 55, 57, 62, 63, 64, 65, 68, 72, 75, 76, 79, 80, 81, 83, 83:1, 84, 89, 92, 95, 99, 111, 141, 173, 180, 184, 207, 211, 212, 214, 218, 221, 223, 224, 225, 226, 227, 232, 233, 240, 241, 242, 243, 247; CI Direct Blue; Blue dyes such as 6, 22, 25, 71, 86, 90, 106, 199; CI Direct Violet; Violet dyes such as 47, 48; CI Direct Green Examples include green dyes such as 59; black dyes such as CI Direct Black 17, 19, 32, 51, 71, 108, 146, 154, 168, etc.

[0028] Of these dyes for color matching, when one or more dyes selected from CI Direct Orange 17, 39, CI Direct Brown 106, 125, 195, CI Direct Red 80, 84, 227, CI Direct Blue 199, and CI Direct Black 19 are included, the print density obtained with the above ink becomes even more vibrant, making it even more preferable. Among these, dyes selected from CI Direct Orange 39, CI Direct Brown 106, 125, 195, CI Direct Red 80, 84, 227, CI Direct Blue 199, and CI Direct Black 19 are preferred, and dyes selected from CI Direct Brown 106, 125, 195, CI Direct Red 80, 84, 227, CI Direct Blue 199, and CI Direct Black 19 are more preferred.

[0029] The total amount of dye is preferably 2.5 to 7.0% by mass relative to the total mass of the ink, more preferably 3.0 to 6.5% by mass, even more preferably 3.5 to 6.3% by mass, and particularly preferably 4.0 to 6.0% by mass. By setting the dye content to 2.5% by mass or more relative to the total mass of the ink, an appropriate image density tends to be obtained, and by setting the dye content to 7.0% by mass or less, dye precipitation tends to be suppressed under storage conditions of -5°C or below.

[0030] The above ink may also contain ink modifiers in addition to the above components. Examples of ink modifiers include organic solvents, viscosity modifiers, surfactants, preservatives, fungicides, pH adjusters, chelating agents, rust inhibitors, water-soluble UV absorbers, antioxidants, and defoaming agents.

[0031] [Organic solvents] There are no particular limitations on specific examples of the above organic solvents, as long as they are solvents containing carbon atoms in their molecules. Specific examples include, for example, C1-C6 alkanols such as propanol, isopropanol, butanol, isobutanol, derbutanol, and terbutanol; carboxylic acid amides such as N,N-dimethylformamide and N,N-dimethylacetamide; lactams such as 2-pyrrolidone, N-methyl-2-pyrrolidone, and N-methylpyrrolidine-2-one; and 1,3-dimethylimidazolidin-2-one and 1,3-dimethylhexahydropyroxide. Cyclic ureas such as limido-2-one; ketones or keto alcohols such as 2-methyl-2-hydroxypentan-4-one and ethylene carbonate; cyclic ethers such as tetrahydrofuran and dioxane; diethylene glycol, 1,2-propanediol (propylene glycol), 1,3-propanediol, 1,2-butylene glycol, 1,4-butylene glycol, triethylene glycol, tetraethylene glycol, phenyldiglycol, dipropylene glycol, polyethylene glycol (preferably molecular weight 400, 800, 15 Mono, oligo, or polyalkylene glycols or thioglycols having C2-C6 alkylene units such as polypropylene glycol, thiodiglycol, and dithiodiglycol (40 or more); C3-C9 polyols (triols) such as glycerin, diglycerin, hexane-1,2,6-triol, and trimethylolpropane; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoallyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-2-ethylhexyl ether (2-ethylhexyldiglycol), diethylene glycol monobutyl ether (butyl carbitol), triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, propylene glycol monopropyl ether, prolene glycol monobutyl ether, and dipropylene glycol monomethyl ether;Examples include C5-C9 alkanediols such as 3-methyl-1,3-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,2-octanediol, 1,6-hexanediol, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, and 2,4-diethyl-1,5-pentanediol; γ-butyrolactone, dimethyl sulfoxide, etc. These water-soluble organic solvents may be used individually or in combination of two or more. Among these, it is preferable to contain diethylene glycol, 1,2-propanediol (propylene glycol), 1,3-propanediol, triethylene glycol, tetraethylene glycol, phenyl diglycol, 3-methyl-1,3-butanediol, 1,6-hexanediol, glycerin, diethylene glycol monobutyl ether, and propylene glycol monopropyl ether; it is more preferable to contain diethylene glycol, 1,2-propanediol, 1,3-propanediol, triethylene glycol, tetraethylene glycol, phenyl diglycol, 3-methyl-1,3-butanediol, glycerin, and diethylene glycol monobutyl ether; it is even more preferable to contain 1,2-propanediol (propylene glycol), 1,3-propanediol, triethylene glycol, phenyl diglycol, 3-methyl-1,3-butanediol, glycerin, and diethylene glycol monobutyl ether; it is even more preferable to contain glycerin and propylene glycol; and it is particularly preferable to use glycerin and propylene glycol in combination. Furthermore, by including at least one selected from the group consisting of diethylene glycol, triethylene glycol, tetraethylene glycol, and phenyl diglycol, dye precipitation tends to be suppressed under storage conditions of -5°C or below.

[0032] The total content of the above organic solvent is preferably 10% by mass or more and 70% by mass or less, more preferably 15% by mass or more and 65% by mass or less, even more preferably 20% by mass or more and 60% by mass or less, and particularly preferably 25% by mass or more and 55% by mass or less.

[0033] It is preferable to use 3-methyl-1,3-butanediol and glycerin as the above organic solvent. The content of 3-methyl-1,3-butanediol and glycerin in the above ink is preferably more than 22% by mass and less than 45% by mass, more preferably more than 25% by mass and less than 44% by mass, even more preferably more than 30% by mass and less than 43% by mass, and particularly preferably more than 35% by mass and less than 42% by mass, based on the total mass of the ink, in order to obtain appropriate moisture retention and viscosity of the ink and to prevent the precipitation of dyes. By increasing the content of 3-methyl-1,3-butanediol and glycerin to more than 22% by mass relative to the total mass of the ink, the viscosity of the ink can be adjusted to a suitable range (viscosity of 3.0 to 13.0 mPa·s at 25℃), and the discharge stability and decapping properties tend to be improved. Furthermore, by limiting the content of 3-methyl-1,3-butanediol and glycerin to less than 45% by mass relative to the total mass of the ink, dye precipitation tends to be suppressed under storage conditions of -5°C or below.

[0034] [Viscosity modifier] The above ink may contain a viscosity modifier. In particular, industrial inkjet printers typically have a defined viscosity range for the ink that can be ejected, based on the specifications of the printer head (the head that ejects the ink). Therefore, a viscosity modifier can be added to the ink to adjust its viscosity to an appropriate range. The viscosity modifier is not particularly limited as long as it is a substance that can adjust the viscosity of the ink; known substances can be used. Specific examples, other than the organic solvents mentioned above, include sugars and hydrophilic resins.

[0035] [Surfactants] The above ink preferably contains a surfactant for purposes such as adjusting surface tension. Examples of surfactants include known surfactants such as anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, silicone-based surfactants, and fluorine-based surfactants.

[0036] Examples of the above-mentioned anionic surfactants include alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, polyoxyethylene alkyl ether sulfates, N-acyl amino acids or their salts, N-acyl methyl taurates, alkyl sulfate polyoxyalkyl ether sulfates, alkyl sulfate polyoxyethylene alkyl ether phosphates, rosinic acid soaps, castor oil sulfates, lauryl alcohol sulfates, alkylphenol type phosphates, alkyl type phosphates, alkylaryl sulfonates, diethyl sulfosaturates, diethylhexyl sulfosaturates, and dioctyl sulfosaturates. Specific examples of commercially available products include, for example, Hytenol LA-10, LA-12, LA-16, Neo Hytenol ECL-30S, and ECL-45, all manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

[0037] Examples of the cationic surfactants mentioned above include 2-vinylpyridine derivatives and poly-4-vinylpyridine derivatives.

[0038] Examples of the above nonionic surfactants include ether-based surfactants such as polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene alkyl ether, and polyoxyethylene distyrenated phenyl ether (commercial products include, for example, Softanol EP-5035, 7085, 9050 from Nippon Shokubai; Pluronic® L-31, L-34, L-44 from Adeka; and Emulgen 108, 120, 147, 150, 220, 350, 420, 1108, A-60, A-90, A-500 from Kao Corporation); polyoxyethylene oleate ester, and polyoxyethylene distearin. Examples include esters such as acid esters, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, and polyoxyethylene stearate; acetylene glycol (alcohol) compounds such as 2,4,7,9-tetramethyl-5-decine-4,7-diol, 3,6-dimethyl-4-octin-3,6-diol, and 3,5-dimethyl-1-hexyn-3-ol (commercial products include, for example, Surfinol 104, 104PG50, 105PG50, 82, 420, 440, 465, 485 from Nisshin Chemical Industry Co., Ltd.; and Olfin STG); and polyglycol ether compounds (commercial products include, for example, TergItol 15-S-7 from SIGMA-ALDRICH). Among these, polyoxyethylene distyleninated phenyl ether and ethylene oxide adducts of 2,4,7,9-tetramethyl-5-decine-4,7-diol are preferred.

[0039] Examples of the above-mentioned amphoteric surfactants include lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyl dimethylaminoacetic acid betaine, polyoctyl polyaminoethylglycine, and imidazoline derivatives.

[0040] Examples of the above-mentioned silicone-based surfactants include polyether-modified siloxanes and polyether-modified polydimethylsiloxanes. Specific examples include BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-347, BYK-348, BYK-349, BYK-3420, BYK-3450, BYK-3455, and BYK-348. Examples include 0, BYK-3565, BYK-3760 (manufactured by Bic Chemie), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-6020, X-22-4515, KF-6011, KF-6012, KF-6015, and KF-6017 (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0041] Examples of the above-mentioned fluorine-based surfactants include perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carbonate compounds, perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide-containing compounds, and polyoxy ether polymer compounds having perfluoroalkyl ether groups in their side chains. Specific examples include Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300 (manufactured by DuPont); and Capstone. FS-30, FS-31, FS-3100 (manufactured by Chemors); PF-151N, PF-154N (manufactured by Omnova); F-114, F-410, F-444, EXP.TF-2066, EXP.TF-2148, EXP.TF-2149, F-430, F-477, F-552, F-553, F-554, F-555, F-556, F-5 Examples include 57, F-558, F-559, F-561, F-562, R-40, R-41, RS-72-K, RS-75, RS-76-E, RS-76-NS, RS-77, EXP.TF-1540, EXP.TF-1760 (manufactured by DIC Corporation); BYK-340, BYK-3440, BYK-3441, etc. (manufactured by Bic Chemie Japan).

[0042] Among the above, nonionic and silicone-based surfactants are preferred, with nonionic surfactants being more preferred. These surfactants may be used individually or in combination of two or more.

[0043] Among the above, it is preferable to include an acetylene glycol-based surfactant. Acetylene glycol-based surfactants have excellent defoaming properties, which reduces the likelihood of dispensing problems caused by the generation of air bubbles in the ink, and tend to result in good initial filling and continuous dispensing performance.

[0044] Furthermore, by adding polyoxyethylene distyrenate phenyl ether to the ink in addition to the acetylene glycol-based surfactant mentioned above, phase separation in the ink is further suppressed, and good ejection stability tends to be obtained.

[0045] The surfactant content in the above ink is typically 0.05% to 4% by mass, preferably 0.06% to 3% by mass, more preferably 0.07% to 2% by mass, even more preferably 0.08% to 1% by mass, and particularly preferably 0.09% to 0.8% by mass, relative to the total mass of the ink. By using surfactants within the above range in the ink, image density, initial ink application, and ejection stability can be improved.

[0046] [Preservatives] Examples of the above-mentioned preservatives include compounds such as organosulfur, organonitrogen-sulfur, organohalogen, haloarylsulfone, iodopropagyl, haloalkylthio, nitrile, pyridine, 8-oxyquinoline, benzothiazole, isothiazolin, dithiol, pyridine oxide, nitropropane, organotin, phenol, quaternary ammonium salt, triazine, thiazine, anilide, adamantane, dithiocarbamate, brominated indanone, benzylbromacetate, and inorganic salts. Specific examples of commercially available preservatives include Proxel GXL(S) and XL-2(S) manufactured by Arch Chemical.

[0047] [Antifungal agent] Examples of the above-mentioned antifungal agents include sodium dehydroacetate, sodium benzoate, sodium pyridinethion-1-oxide, ethyl p-hydroxybenzoate, and 1,2-benzisothiazolin-3-one, as well as salts thereof.

[0048] [pH adjuster] Examples of pH adjusters include alkanolamines such as diethanolamine, triethanolamine, N-methyldiethanolamine, and 2-amino-2-methyl-1-propanol; alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; ammonium hydroxide (ammonia water); alkali metal carbonates such as lithium carbonate, sodium carbonate, sodium bicarbonate, and potassium carbonate; alkali metal salts of organic acids such as sodium silicate and potassium acetate; and inorganic bases such as disodium phosphate. Among these, diethanolamine, triethanolamine, lithium hydroxide, sodium hydroxide, and potassium hydroxide are preferred, diethanolamine and triethanolamine are more preferred, and triethanolamine is even more preferred. The above-mentioned ink, by containing the above-mentioned alkanolamine, can provide a stable ink that suppresses pH fluctuations over a long period of time and does not undergo changes in various physical properties. This effect cannot be obtained when using inorganic compounds such as hydroxides of Group 1 elements of the periodic table (e.g., sodium hydroxide). For this reason, when providing the above-mentioned stable ink, it is preferable that the ink further contains an alkanolamine as a pH adjuster.

[0049] [Chelating agent] Examples of the chelating agents mentioned above include disodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uracil diacetate, α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin.

[0050] [Rust inhibitor] Examples of the above-mentioned rust inhibitors include acidic sulfites, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitride, pentaerythritol tetranitrate, and dicyclohexylammonium nitride.

[0051] [Water-soluble UV absorber] Examples of the above-mentioned water-soluble ultraviolet absorbers include, for example, sulfonated benzophenone compounds, benzotriazol compounds, salicylic acid compounds, cinnamic acid compounds, and triazine compounds.

[0052] [Antioxidant] Examples of the above antioxidants include, for example, various organic and metal complex-based colorfastness inhibitors. Examples of the above organic colorfastness inhibitors include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, ascorbic acid, isoascorbic acid, chlorogenic acid, sulfur dioxide, catechins, dibutylhydroxytoluene, tocopherol, and butylhydroxyanisole.

[0053] [Antifoaming agent] The above-mentioned defoaming agents include acetylene-based defoaming agents such as the Surfinol 104 series (104A, 104E, 104H, 104PA, 104PG-50), Surfinol DF110D, Surfinol AD01, Surfinol MD-20, Surfinol DF-58, BYK-017, BYK-018, BYK-019, BYK-021, BYK-022, BYK-023, BYK-024, BYK-025, BYK-028, BYK-044, BYK-092, BYK-1610, BYK-1611, BY Examples of defoaming agents include silicone-based defoamers such as K-1615, BYK-1617, BYK-1650, BYK1679, BYK-1719, BYK-1723, BYK-1724, BYK-1730, BYK-1770, BYK-1781, BYK-1786, and BYK-1789; mineral oil-based defoamers such as BYK-035, BYK-037, BYK-038, and BYK-1630; higher alcohol derivatives such as Bisform CS, Bisform ECC, and Bisform TDI-1; and fatty acid derivatives such as Bisform TS-10. The defoaming agent is preferably an acetylene-based or silicone-based defoamer. These defoaming agents may be used individually or in combination of two or more. The amount of defoaming agent added is preferably 0.01 to 3%, more preferably 0.01 to 2%, and even more preferably 0.01 to 1%. An amount of 0.01% or more provides good defoaming effect, while an amount of 3% or less provides good discharge properties.

[0054] [Ink viscosity] The viscosity of the above ink at 25°C is preferably 3.0 to 13.0 mPa·s, more preferably 3.5 to 12.0 mPa·s, even more preferably 4.0 to 11.0 mPa·s, and particularly preferably 4.5 to 10.0 mPa·s. Inks that satisfy the above viscosity range tend to have good ejection response in high-speed printing.

[0055] The viscosity of the above ink can be measured, for example, using an E-type viscometer (TV-22, manufactured by Toki Sangyo Co., Ltd.) under conditions of 25°C and 50 rpm.

[0056] [Static surface tension of ink] The static surface tension of the above ink at 25°C is preferably 32-42 mN / m, more preferably 33-41 mN / m, more preferably 34-40 mN / m, and particularly preferably 35-39 mN / m, from the viewpoint of achieving sufficient wettability for various printing media.

[0057] The static surface tension of the above ink can be measured, for example, using a surface tensimeter (CBVP-Z, manufactured by Kyowa Interface Science Co., Ltd.) by the platinum plate method at a temperature of 25°C.

[0058] [Ink pH] For the purpose of improving storage stability, the pH of the above ink is preferably 5.0 to 11.0, and more preferably 7.0 to 10.0.

[0059] When preparing the above-mentioned ink, known manufacturing methods can be used. For example, one method involves preparing the ink by adding and mixing a dye, a surfactant, water, and, if necessary, an ink preparing agent. Alternatively, if necessary, after preparing the ink, microfiltration may be performed using a membrane filter or the like to remove impurities from the ink. In particular, when using the ink set of the present invention for inkjet recording, microfiltration is preferable. The pore size of the filter used for microfiltration is usually 0.1 to 2.0 μm, preferably 0.5 to 1.0 μm.

[0060] An ink set including the above-mentioned ink and other inks is also included in the present invention. Examples of the above-mentioned ink sets include an ink set containing one or more of the above-mentioned inks, an ink set containing one or more of the above-mentioned inks and one or more of other inks other than the above-mentioned inks. The other inks other than the above-mentioned inks are not particularly limited as long as their composition is different from the above-mentioned inks, but it is preferable that they have a different hue from the above-mentioned inks.

[0061] The above-mentioned ink and ink set can be used in various printing applications. For example, they are suitable for various types of printing, information printing, and photographic printing, and are particularly preferred for use in inkjet printing.

[0062] The present invention also includes a method for manufacturing an inkjet printed material, which involves ejecting droplets of the above-mentioned ink from an inkjet head and adhering them to a printing medium to obtain a printed material, and an inkjet recording method, which involves ejecting droplets of any of the inks constituting the above-mentioned ink set from an inkjet head and adhering them to a printing medium to perform recording.

[0063] <Inkjet recording method> The present invention also includes an inkjet recording method that performs printing by ejecting droplets of the above-mentioned ink, or each ink constituting the above-mentioned ink set, from an inkjet printer and adhering them to a printing medium.

[0064] An inkjet printer can use any known recording method. Specific examples of inkjet methods include, for example, charge control methods, drop-on-demand (pressure pulse) methods, acoustic inkjet methods, and thermal inkjet methods, with the drop-on-demand method being preferred.

[0065] <Print media> The printing media is not particularly limited as long as it is a material to which the above-mentioned inks, or each ink constituting the above-mentioned ink set, can adhere. Examples include inkjet paper, inkjet film, glossy paper, corrugated cardboard, liner paper contained in corrugated cardboard, etc. Representative commercially available products include, for example, Pictorico (manufactured by Asahi Glass Co., Ltd.), Professional Photo Paper, Super Photo Paper, Matte Photo Paper, Gloss Gold, Platinum Grade (all manufactured by Canon Inc.), Photo Paper (Glossy), Photo Matte Paper, Photo Paper Crispia (High Gloss) (all manufactured by Seiko Epson Corporation), Premium Plus Photo Paper, Premium Gloss Film, Photo Paper, Advanced Photo Paper (all manufactured by Hewlett-Packard Japan, Ltd.), PhotoLike QP (manufactured by Konica Corporation), and Gakusai Photo Finish Pro (manufactured by Fujifilm Corporation). Plain paper, fine paper, and coated paper can also be used. Printed media printed with the above ink, and an ink media set consisting of the above ink and printed media printed with the above ink are also included in the present invention.

[0066] Industrial inkjet printers, in order to achieve high printing speeds, are configured as line-head inkjet printers, and single-pass printing is also preferred. With the above-mentioned ink, good quality prints can be obtained even under such printing conditions.

[0067] Regarding all of the above, combinations of preferred elements are more preferable, and combinations of preferred elements are even more preferable. The same applies to combinations of preferred elements and preferred elements, and combinations of preferred elements and even more preferable elements. Furthermore, unless otherwise specified, all of the above-mentioned components can be used individually or in combination of two or more elements.

[0068] The ink of the present invention enables the provision of printed materials that have good hue and excellent ozone resistance, and exhibits extremely good storage stability, with no dye precipitation, physical property changes, or hue changes after long-term storage. Furthermore, images recorded with the above ink have very high image density and provide recorded images with ideal hue. Moreover, it exhibits good fastness in various aspects such as lightfastness, moisture resistance, and abrasion resistance. Furthermore, the ink of the present invention does not undergo any change in physical properties, even when used in a continuous inkjet printer with relatively long time intervals for recirculation, or when used intermittently in an on-demand inkjet printer. [Examples]

[0069] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples. In addition, in the structural formulas of the compounds obtained in the examples, acidic functional groups such as sulfo groups are described in the form of free acids. Unless otherwise specified, the inks were prepared under stirring. The "water" used in the examples is deionized water.

[0070] [Synthesis Example 1]: Dye Synthesis A dye represented by the following formula (2) was synthesized according to the method described in International Publication No. 2013 / 035560.

[0071] [ka]

[0072] [Examples 1-4, Comparative Examples 1 and 2]: Ink Preparation The components listed in Table 1 below were mixed, stirred for 1 hour, and then filtered through a 0.8 μm membrane filter (product name: cellulose acetate filter paper, manufactured by Advantec Co., Ltd.) to obtain inks for Examples 1-4 and Comparative Examples 1-7. The viscosity and static surface tension listed in Table 1 were measured using an E-type viscometer (TV-22, manufactured by Toki Sangyo Co., Ltd.) and a surface tension meter (CBVP-Z, manufactured by Kyowa Interface Science Co., Ltd.), respectively. The abbreviations in Table 1 below represent the following: A blank space indicates 0 copies. Compound (2): The compound obtained in Synthesis Example 1. DK19: CI Direct Black 19 AK2:CI Acid Black 2 DY132: CI Direct Yellow 132 DY86: CI Direct Yellow 86 DO39: CI Direct Orange 39 AR249: CI Acid Red 249 DR227: CI Direct Red 227 DB199: CI Direct Blue 199 GL: Glycerin (manufactured by Junsei Chemical Co., Ltd.) PG: Propylene glycol (manufactured by Junsei Chemical Co., Ltd.) SF440: Surfinol 440 (manufactured by Nisshin Chemical Industry Co., Ltd.) TEA: Triethanolamine (manufactured by Junsei Chemical Co., Ltd.)

[0073] [Table 1]

[0074] [Inkjet recording] Each ink was inkjet recorded onto photographic paper (Epson, product name Crispia) using a printer equipped with a Kyocera Corporation inkjet head KJ4B-1200, under conditions of droplet size 3pl and resolution 1200dpi x 1200dpi, to obtain initial printed images. During inkjet recording, image patterns at 100% and 50% density were created to obtain dark black and light black recordings. These were used as test pieces for the following evaluation tests. The stage heater temperature was set so that the substrate temperature during printing was 32°C.

[0075] [Colorimeter and color measurement conditions] When color measurement was necessary in the following evaluation tests, it was performed using the colorimeter and color measurement conditions described below. Colorimeter: eXact by X-Rite. Color measurement conditions: Light source D50, viewing angle 2°, Status E.

[0076] [Hue evaluation test] For each example and comparative example test piece obtained in the "inkjet recording" described above, L*, a*, and b* were measured for the 100% density grayscale portion, and the saturation C* value was calculated using the following formula. C*=(a* 2 +b* 2 ) 1 / 2 The obtained C* value, when closest to 0, indicates a more desirable black hue, and was evaluated according to the following four criteria. The results are shown in Table 6 below. A:C* is less than 8.0. B:C* is between 8.0 and 8.5. C:C* is between 8.5 and 10.0. D:C* is 10.0 or higher.

[0077] [Ozone resistance test] The 50% density gradation portions of the test pieces for each example and comparative example obtained in the "Inkjet Recording" described above were placed in an Ozone Weather Meter OMS-L (manufactured by Suga Test Instruments Co., Ltd.) and subjected to an 8-hour ozone exposure test under conditions of 23°C, 50% RH relative humidity, and 5 ppm ozone concentration. L1*, a1*, b1* before exposure and L2*, a2*, b2* after exposure were measured for each test piece, and the color difference △E = {(L2*-L1*)} was calculated from the obtained values. 2 +(a2*-a1*) 2 +(b2*-b1*) 2} 1 / 2 The color difference (△E) was calculated based on the formula, and the ozone resistance was evaluated according to the evaluation criteria below. A smaller color difference (△E) indicates less image quality degradation and superior ozone resistance. The results are shown in Table 2 below. A: △E is less than 4.0. B:△E is between 4.0 and 5.5. C:△E is between 5.5 and 6.5. D:△E is 6.5 or higher.

[0078] [Table 2]

[0079] As is clear from the results in Table 2, each example ink was found to have good hue and excellent ozone resistance in the recordings obtained using the ink. [Industrial applicability]

[0080] To provide an ink that enables the production of printed materials that possess good color hues and excellent ozone resistance.

Claims

1. An ink comprising dye A represented by the following formula (1), dye B selected from C.I. Direct Yellow, dye C selected from C.I. Acid Red, and water, wherein when the total mass percentage of dye B is b and the total mass percentage of dye C is c, the value obtained by b / c is greater than 0.7 and less than 5.

5. 【Chemistry 1】 [In formula (1), R １ , R ２ , R ５ , R ６ and R ７ Each of these independently represents a group selected from the group consisting of a hydrogen atom, a halogen atom, a cyano group, a hydroxyl group, a carboxyl group, a sulfo group, a sulfamoyl group, a nitro group, an optionally substituted alkoxy group, an optionally substituted alkylsulfonyl group, an alkyl group, an optionally substituted arylsulfamoylamino group, and an alkylcarbonylamino group. ３ and R ４ Each of these independently represents a group selected from the group consisting of a hydrogen atom, a halogen atom, a cyano group, a sulfo group, a carboxyl group, a nitro group, an optionally substituted alkoxy group, and an alkyl group. n represents 0 or 1.

2. The ink according to claim 1, wherein the viscosity at 25°C is 3.0 to 13.0 mPa·s and the static surface tension at 25°C is 32 to 42 mN / m.

3. Furthermore, the ink according to claim 1 or 2 contains a surfactant in an amount of 0.05% to 4% by mass relative to the total mass of the ink.

4. The ink according to claim 1 or 2, wherein the surfactant comprises at least an acetylene glycol-based surfactant.

5. In the aforementioned formula (1), R １ is a carboxy group or a sulfo group, R ２ is a hydrogen atom, R ６ is a nitro group, a carboxy group, or a sulfo group, and n is 1, the ink according to claim 1 or 2.

6. In formula (1) above, R １ and R ３ is a sulfo group, R ４ is a hydrogen atom, R ５ is a hydrogen atom, a carboxyl group, or a sulfo group, and R ６ is a nitro group, a carboxyl group, or a sulfo group, R ７ The ink according to claim 1 or 2, wherein n is a hydrogen atom and n is 1.

7. An ink set comprising the ink described in claim 1 or 2 and another ink.

8. An inkjet recording method that performs recording by ejecting ink droplets according to claim 1 or 2 from an inkjet head and adhering them to a recording material.

9. An inkjet recording method that performs recording by ejecting droplets of any of the inks constituting the ink set described in claim 7 from an inkjet head and adhering them to a recording material.

Images