Inkjet ink and ink set

Abstract

To provide an inkjet ink which has excellent deinkability, that is, from which the colorant can be easily removed.SOLUTION: An inkjet ink contains a colorant, wherein the colorant is one or more selected from the group consisting of iron oxide compounds, phycocyanin, caramel, copper-chlorophyllin compounds, capsaicin, carminic acid, betanin, cyanidin glycosides, carmine, β-carotene, lutein, norbixin, and curcumin.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to ink-jet inks and ink sets. [Background technology]

[0002] Coal-tar dyes are often used in brightly colored foods, and have been used in a wide range of foods, including sweets such as sweet breads, chocolates, jellies, and gum, as well as pickles such as pickled radish and red pickled ginger. Against this background, methods for suppressing the fading of tar dyes have been investigated (Patent Document 1). Its uses are diverse, including as a printing ink for orally administered products and for printing on food products. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2005 / 108503 Brochure [Patent Document 2] JP 2000-42089 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, there are some colorants used in food, including tar colorants, that raise concerns about the color remaining on the tongue. In addition, pigments derived from fossil fuels (petroleum, coal), such as tar pigments, are difficult to remove from printed matter, making it difficult to recycle the base material. Therefore, they are often incinerated as waste, which reduces CO 2 From the perspective of reduction, there are also some undesirable aspects. Therefore, an object of the present invention is to provide an ink-jet ink that is excellent in deinking properties, that is, from which the dye can be easily removed. [Means for solving the problem]

[0005] As a result of extensive investigations, the present inventors have found that the above problems can be solved by using an ink-jet ink containing a specific dye, and have thus completed the present invention. An example of the configuration of the present invention that solves the above problem is as follows.

[0006] Item 1. An ink-jet ink containing a dye, The ink-jet ink is characterized in that the pigment is one or more selected from the group consisting of iron oxide compounds, phycocyanin, caramel, copper chlorophyllins, capsaicin, carminic acid, betanin, cyanidin glycosides, carmine, β-carotene, lutein, norbixin, and curcumin.

[0007] Item 2. The iron oxide compound is triiron tetroxide (Fe 3 O 4 ), iron oxide (Fe 2 O 3 2. The ink-jet ink according to item 1, wherein the at least one selected from the group consisting of iron oxyhydroxide (FeOOH) and iron oxyhydroxide (FeOOH).

[0008] Item 3. The ink-jet ink according to item 1 or 2, further comprising a solvent.

[0009] Item 4. The ink-jet ink according to any one of Items 1 to 3, further comprising a binder resin.

[0010] Item 5. The ink-jet ink according to any one of Items 1 to 4, further comprising a surfactant.

[0011] Item 6. The ink-jet ink according to any one of Items 1 to 5, further comprising water.

[0012] Item 7. The ink-jet ink according to any one of Items 1 to 6, which is used for food, cardboard, food packaging, or textiles.

[0013] Item 8. An ink set comprising the ink-jet ink according to any one of items 1 to 7. Effect of the Invention

[0014] According to the present invention, it is possible to provide an ink-jet ink having excellent ejection properties and deinking properties. Since the ink-jet ink according to the present invention has good deinking properties, it is expected that the substrate can be recycled, and therefore it is eco-friendly because it is expected that the environmental load can be reduced. Furthermore, when applied to food, it is expected to reduce the color that remains on the tongue. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] (Inkjet ink) The ink-jet ink according to the present invention is a composition containing a dye. The pigment is characterized in that it is one or more selected from the group consisting of iron oxide compounds, phycocyanin, caramel, copper chlorophyllins, capsaicin, carminic acid, betanin, cyanidin glycosides, carmine, β-carotene, lutein, norbixin, and curcumin.

[0016] Iron oxide compounds include triiron tetroxide (Fe 3 O 4 ), iron oxide (Fe 2 O 3 It is preferable that the metal oxide is one or more selected from the group consisting of iron oxyhydroxide (FeOOH) and iron oxyhydroxide (FeOOH).

[0017] The pigments may be any of those extracted from natural products, those processed from natural extracts, those synthesized from raw materials derived from natural products, and those chemically synthesized artificially. From the viewpoint of eco-friendliness, however, those extracted from natural products, those processed from natural extracts, and those synthesized from raw materials derived from natural products, i.e., natural pigments, are preferred. From the viewpoint of solubility and dispersibility, the dye may be subjected to lake treatment or resin treatment within a range that does not impair the required properties.

[0018] For example, a dye can be incorporated into an inkjet ink by using a colorant that contains the dye. The colorant is preferably in the form of a powder or liquid.

[0019] For example, colorants that can be used in the ink-jet ink according to the present invention include those described below. · "SUNFOODS (trademark) Black Iron Oxide (Pigment: Triiron tetroxide (Fe 3 O 4 ), Shape: Powder, Color space: Black) SUNFOODS (trademark) Red Iron Oxide (pigment: iron trioxide (Fe 2 O 3 ), Shape: Powder, Color space: Red) - "SUNFOODS (trademark) Yellow Iron Oxide (pigment: iron oxyhydroxide (FeOOH), form: powder, color space: yellow)" - "LINABLUE (registered trademark) Blue spirulina extract (pigment: phycocyanin, form: powder or liquid, color space: blue)" "SUNFOODS (trademark) Natural Caramel (color: caramel, form: liquid, color space: brown)" "SUNFOODS (trademark) Chlorophyll (pigment: copper chlorophyllins, form: powder or liquid, color space: green)" "SUNFOODS(TM) Paprika (colorant: capsaicin, form: powder or liquid, color space: orange)" "SUNFOODS(TM) Cochineal (Pigment: Carminic Acid, Form: Powder or Liquid, Color Space: Orange)" "SUNFOODS(TM) Beet (pigment: betanin, form: powder or liquid, color space: red)" "SUNFOODS(trademark) Anthocyanin (pigment: cyanidin glycoside, form: powder or liquid, color space: red to purple)" "SUNFOODS(TM) Carmine (pigment: carmine, form: liquid, color space: red)" "SUNFOODS (trademark) Natural White (pigment: β-carotene, form: powder or liquid, color space: white)" "SUNFOODS(TM) Beta Carotene (Pigment: β-carotene, Form: Powder or Liquid, Color Space: Yellow)" "SUNFOODS(trademark) Natural Beta Carotene (pigment: beta-carotene, form: liquid, color space: yellow)" "SUNFOODS(trademark) Lutein (pigment: lutein, form: liquid, color space: yellow)" "SUNFOODS(TM) Annatto (Pigment: Nobilixin, Form: Powder, Color Space: Yellow)" ·"SUNFOODS(TM) Turmeric (pigment, curcumin, shape: powder, color space: yellow)"

[0020] The type of dye (colorant) used in the inkjet ink (composition) is preferably one or two or more types. The colorant is preferably used so that the content of the pigment contained in the colorant is a predetermined content in the inkjet ink. The lower limit of the total content of dyes in 100% by mass of the ink-jet ink (composition) is preferably 1.0% by mass or more, and more preferably 3.0% by mass or more. The upper limit of the total content of dyes in 100% by mass of the ink-jet ink (composition) is preferably 15.0% by mass or less, and more preferably 10.0% by mass or less. The total content of the dyes in 100% by mass of the ink-jet ink (composition) is preferably 1.0 to 15.0% by mass, and more preferably 3.0 to 10.0% by mass.

[0021] (Other Ingredients) The ink-jet ink according to the present invention preferably contains a solvent from the viewpoints of compatibility with the dye and moisture retention.

[0022] Examples of the solvent include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycols having a molecular weight of 2000 or less, propylene glycol, dipropylene glycol, tripropylene glycol, isopropylene glycol, isobutylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 3-methyl-1,3-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 1,2-hexanediol, 1,6-hexanediol, mesoerythritol, pentaerythritol, glycerin, and ethylene urea.

[0023] The number of types of solvents used in the inkjet ink (composition) is preferably one or more, and more preferably one to three. The lower limit of the total content of the solvent in 100% by mass of the ink-jet ink (composition) is preferably 1.0% by mass or more, more preferably 10.0% by mass or more, and even more preferably 15.0% by mass or more. The upper limit of the total content of the solvent in 100% by mass of the ink-jet ink (composition) is preferably 45.0% by mass or less, more preferably 35.0% by mass or less, and even more preferably 25.0% by mass or less. The total content of the solvent in 100% by mass of the ink-jet ink (composition) is preferably 1.0 to 45.0% by mass, more preferably 10.0 to 35.0% by mass, and even more preferably 15.0 to 25.0% by mass.

[0024] From the viewpoints of abrasion resistance and fixation property, the ink-jet ink according to the present invention preferably contains a binder resin.

[0025] Examples of binder resins include polyvinyl alcohol, gelatin, polyethylene oxide, polyvinylpyrrolidone, acrylic resins, urethane resins, olefin resins, modified polyolefin resins (such as acid-modified polypropylene), dextran, dextrin, carrageenan (κ, ι, λ, etc.), agar, pullulan, water-soluble polyvinyl butyral, hydroxyethyl cellulose, carboxymethyl cellulose, etc., but from the viewpoint of weather resistance, styrene-acrylic resins, etc. are preferred.

[0026] The weight average molecular weight (Mw) of the binder resin is preferably from 50,000 to 1,000,000, more preferably from 50,000 to 500,000, and even more preferably from 50,000 to 250,000. The Mw of the binder resin is a value measured in terms of standard polystyrene by gel permeation chromatography (GPC). In detail, it was determined by a GPC-MALS method in which a multi-angle light scattering detector was connected to GPC under the measurement conditions described below. GPC main unit: Agilent Technologies "LC1100" series Column: Showa Denko Co., Ltd. "SHODEX SB806MHQ" Eluent: N / 3 phosphate buffer (pH 3) containing N / 10 sodium nitrate Flow rate: 1.0ml / min Detector 1: Wyatt Technology, multi-angle light scattering detector DAWN Detector 2: Showa Denko Co., Ltd., differential refractive index detector RI-101

[0027] The acid value of the binder resin is preferably from 10 to 200 mgKOH / g, and more preferably from 50 to 150 mgKOH / g, from the viewpoints of dispersibility and fixability. The acid value can be measured according to JIS standard K2501.

[0028] The glass transition temperature (Tg) of the binder resin is preferably from 20 to 100°C, and more preferably from 50 to 100°C. The glass transition temperature (Tg) can be measured according to JIS standard K7121.

[0029] Examples of binder resins include "JONCRYL PDX-7696", "JONCRYL PDX-7700", "JONCRYL PDX-7780", "JONCRYL 89-E", and "JONCRYL 89J" (all trade names (JONCRYL is a registered trademark) manufactured by BASF Japan Ltd.), "Hi-Loss-X BE7503" (manufactured by Seiko PMC Corporation), "Vinyblan 745", and "Vinyblan 747" (manufactured by Nissin Chemical Industry Co., Ltd.).

[0030] The type of binder resin used in the inkjet ink (composition) is preferably one or two or more types. The lower limit of the total content of the binder resin in 100% by mass of the inkjet ink (composition) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more. The upper limit of the total content of the binder resin in 100% by mass of the inkjet ink (composition) is preferably 5.0% by mass or less, more preferably 4.0% by mass or less, and even more preferably 3.0% by mass or less. From the viewpoints of ejection property and abrasion resistance, the total content of the binder resin in 100% by mass of the inkjet ink (composition) is preferably 0.1 to 5.0% by mass, more preferably 0.5 to 4.0% by mass, and even more preferably 1.0 to 3.0% by mass.

[0031] The ink-jet ink according to the present invention preferably contains a surfactant from the viewpoint of imparting substrate wettability.

[0032] Examples of the surfactant include anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. From the viewpoint of ink storage stability, anionic surfactants or nonionic surfactants are preferred. Examples of the anionic surfactant include alkylbenzenesulfonates, alkylphenylsulfonates, alkylnaphthalenesulfonates, higher fatty acid salts, sulfates or sulfonates of higher fatty acid esters, sulfates or sulfonates of higher alcohol ethers, higher alkyl sulfosuccinates, polyoxyethylene alkyl ether carboxylates, sulfates, phosphates or alkyl phosphates of polyoxyethylene alkyl ethers, and the like.

[0033] Examples of the nonionic surfactant include glycol-based surfactants, silicone-based surfactants, fluorine-based surfactants, and acetylene diol-based surfactants.

[0034] Examples of glycol-based surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylaryl ethers, polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyglycerin fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene fatty acid amides, polyoxyethylene-polyoxypropylene block copolymers, and the like.

[0035] Examples of silicone surfactants include polysiloxane compounds and polyether-modified organosiloxanes. Commercially available silicone surfactants include, for example, the "TegoWet (registered trademark)" series manufactured by Evonik, the "BYK (registered trademark)" series manufactured by BYK Japan, and the "KF" series manufactured by Shin-Etsu Chemical Co., Ltd.

[0036] Examples of the fluorine-based surfactant include perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, oxyethylene perfluoroalkyl ethers, perfluoroalkyl phosphates, perfluoroalkyl betaines, and perfluoroalkyl amine oxides. Examples of commercially available fluorine-based surfactants include the "Megafac (registered trademark)" series manufactured by DIC Corporation, the "Ftergent (registered trademark)" series manufactured by Neos Corporation, and the "Novec (registered trademark)" series manufactured by Sumitomo 3M Limited.

[0037] Acetylene diol surfactants are surfactants that have a carbon-carbon triple bond in the molecule, and examples of such surfactants include acetylenic diol (having an acetylene bond and two hydroxyl groups in the same molecule) surfactants and surfactants in which alkylene oxides such as ethylene oxide and propylene oxide are added to acetylenic diol. Examples of acetylene diol surfactants include 2,4,7,9-tetramethyl-5-decyne-4,7-diol and alkylene oxide adducts of 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 2,4-dimethyl-5-decyne-4-ol and alkylene oxide adducts of 2,4-dimethyl-5-decyne-4-ol, and the like. Commercially available acetylene diol surfactants include, for example, the "Surfynol (registered trademark)" series manufactured by Evonik or Nissin Chemical Industry Co., Ltd., the "Olfine (registered trademark)" series manufactured by Nissin Chemical Industry Co., Ltd., and the "Acetylenol (registered trademark)" series manufactured by Kawaken Fine Chemical Co., Ltd.

[0038] The HLB value of the surfactant is preferably from 2.5 to 10.0, more preferably from 3.0 to 9.0, and even more preferably from 3.5 to 6.0, from the viewpoint of controlling the ink interface. The "HLB (Hydrophilic-Lipophilic Balance) value" of a surfactant is a value defined by the following calculation formula (Griffin formula) according to the Griffin method. HLB value = 20 x [sum of chemical formula weights of hydrophilic parts] / molecular weight

[0039] The number of types of surfactants used in the inkjet ink (composition) is preferably one or more, and more preferably one or two. The lower limit of the total content of the surfactant in 100% by mass of the inkjet ink (composition) is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more. The upper limit of the total content of the surfactant in 100% by mass of the inkjet ink (composition) is preferably 2.0% by mass or less, more preferably 1.5% by mass or less, and even more preferably 1.2% by mass or less. From the viewpoint of substrate wettability, the total content of the surfactant in 100% by mass of the inkjet ink (composition) is preferably 0.01 to 2.0% by mass, more preferably 0.05 to 1.5% by mass, and even more preferably 0.1 to 1.2% by mass.

[0040] From the viewpoints of safety and environmental protection, the ink-jet ink according to the present invention is preferably an aqueous ink (containing water).

[0041] Examples of water include distilled water and ion-exchanged water.

[0042] The type of water used in the inkjet ink (composition) is preferably one or two or more types. The lower limit of the total content of water in 100% by mass of the ink-jet ink (composition) is preferably 40.0% by mass or more, more preferably 45.0% by mass or more, and even more preferably 50.0% by mass or more. The upper limit of the total water content in 100% by mass of the ink-jet ink (composition) is preferably 75.0% by mass or less, more preferably 70.0% by mass or less, and even more preferably 65.0% by mass or less. The total content of water in 100% by mass of the ink-jet ink (composition) is preferably 40.0 to 75.0% by mass, more preferably 45.0 to 70.0% by mass, and even more preferably 50.0 to 65.0% by mass, from the viewpoints of ejection performance and colorant stability.

[0043] In addition to the above-mentioned components, the inkjet ink according to the present invention may further contain other additives, such as a pH adjuster, a preservative, a polyolefin wax, an antioxidant, a viscosity adjuster, a wetting agent (a drying inhibitor), a penetrating agent, a chelating agent, a plasticizer, and an ultraviolet absorber, as necessary.

[0044] Examples of the pH adjuster include potassium dihydrogen phosphate, disodium hydrogen phosphate, sodium hydroxide, lithium hydroxide, potassium hydroxide, ammonia, diethanolamine, triethanolamine, triisopropanolamine, potassium carbonate, sodium carbonate, and sodium hydrogen carbonate.

[0045] Preservatives include sodium benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, 1,2-dibenzisothiazolin-3-one and the like. Commercially available preservatives may be used, such as "ACTICIDE (registered trademark) B20" (product name, manufactured by Thor Japan Co., Ltd.) and "Proxel (registered trademark) GXL" (product name, manufactured by SC Johnson).

[0046] Polyolefin waxes include waxes or copolymers made from olefins such as ethylene, propylene, butylene, or derivatives thereof. Examples of the polyolefin wax include polyethylene wax, polypropylene wax, polybutylene wax, and modified waxes of these waxes. Among these, oxidized polyethylene wax obtained by subjecting polyethylene wax to an oxidative modification treatment is preferred from the viewpoint of improving image fastness of printed matter. As the polyolefin wax, commercially available products may be used, such as the "AQUACER (registered trademark)" series (manufactured by BYK-Chemie Japan).

[0047] Examples of the antioxidant include phenol-based antioxidants, amine-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants.

[0048] The type of additive used in the inkjet ink (composition) is preferably one or two or more types. The lower limit of the total content of the additives in 100% by mass of the ink-jet ink (composition) is preferably 0.01% by mass or more, and more preferably 0.02% by mass or more. The upper limit of the total content of the additives in 100% by mass of the ink-jet ink (composition) is preferably 5.0% by mass or less, and more preferably 3.0% by mass or less. From the viewpoint of jetting properties, the total content of the additives in 100% by mass of the ink-jet ink (composition) is preferably 0.01 to 5.0% by mass, and more preferably 0.02 to 3.0% by mass. (Physical properties of inkjet ink)

[0049] The viscosity of the ink-jet ink according to the present invention at 25° C. is preferably from 3.0 to 12.0 mPa·s, more preferably from 3.0 to 10.0 mPa·s, and even more preferably from 3.0 to 6.0 mPa·s, from the viewpoint of suitability for ink-jet heads. The viscosity of the inkjet ink is a value measured, for example, using a cone-plate type rotational viscometer equivalent to an E-type viscometer under the following conditions. Measurement equipment: TVE-25 type viscometer (Toki Sangyo Co., Ltd., TVE-25L) Calibration standard solution: JS20 Measurement temperature: 25℃ Rotation speed: 10~100rpm Injection volume: 1200μL

[0050] The surface tension of the ink-jet ink according to the present invention at 25° C. is preferably from 24.0 to 35.0 mN / m, and more preferably from 24.0 to 30.0 mN / m, from the viewpoints of ejection property and wettability. The surface tension of the ink-jet ink at 25° C. is a value measured by the Whilhelmy method.

[0051] The pH of the inkjet ink at 25° C. is preferably from 6.0 to 10.5, and more preferably from 7.5 to 9.0, from the viewpoint of influence on components. The pH value of the ink-jet ink at 25° C. is a value measured by the glass electrode method.

[0052] (Inkjet ink manufacturing method) The inkjet ink can be produced by, for example, an inkjet ink production method that includes at least a step of mixing a dye (colorant), a solvent, a binder resin, a surfactant, and water. The mixing method is not particularly limited, and the above-mentioned components may be mixed all at once or sequentially.

[0053] (Inkjet ink applications) The ink-jet ink according to the present invention has good deinking properties for the coloring matter, and therefore is suitable for food applications in that little color remains on the tongue. In addition, from the viewpoint of recyclability of the substrate, it is suitable for use in cardboard, food packaging, or textiles.

[0054] The ink-jet ink according to the present invention can also be used as part of an ink set. For example, an ink-jet ink containing phycocyanin as a pigment can be combined with an ink-jet ink containing an iron oxide compound, caramel, copper chlorophyllins, capsaicin, carminic acid, betanin, cyanidin glycoside, carmine, β-carotene, lutein, norbixin, or curcumin as a pigment to form an ink set. Furthermore, it may be combined with an ink-jet ink containing carbon black or the like as a pigment. EXAMPLES

[0055] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples in any way.

[0056] 1.Materials used <Coloring agent>

[0057] [Table 1] <Solvent> Glycerin (Gly) Propylene glycol (PG) Ethylene urea <Binder resin> Styrene-acrylic resin (JONCRYL PDX-7696 (PDX-7696), Mw100,000~200,000, acid value 122mgKOH / g, Tg86℃, manufactured by BASF) <Surfactant> Acetylene diol surfactants (Surfynol 420 (SF420), manufactured by Evonik, HLB value = 4.0) Silicone surfactants (TegoWet280 (TegoWet), manufactured by Evonik, HLB value = 3.5) <Water> Ion-exchanged water

[0058] 2. Evaluation of inkjet inks <2-1. Dischargeability> Using the inkjet inks obtained in each of the Examples and Comparative Examples, an inkjet printer (Epson Corporation, "PX-S270T") was used to continuously print 100 solid patterns on photo paper in an atmosphere of 40°C and 30% RH, and finally a nozzle check pattern was printed. The printing conditions were image resolution: 600 dpi x 600 dpi, print mode: print quality: standard, and plain business paper was used. The obtained nozzle check pattern was visually observed to check for the presence or absence of missing nozzles, and the ejection performance was evaluated according to the following criteria. <Evaluation criteria> ○: No missing nozzles at all ×: Nozzle missing <2-2. Deinking properties> Using the inkjet inks obtained in each of the Examples and Comparative Examples, samples (A4 solid prints, 3 sheets) were printed on high-quality paper using an inkjet printer (Epson Corporation, "PX-S270T") in an atmosphere of 40°C and 30% RH. The sample was added to a mixer (Powerix Multi BL42X1JP, manufactured by T-fal), and then 700 ml of water at 30°C was added. While gently stirring with a stirring rod, 3 ml of a 3.5% by mass aqueous solution of sodium hydroxide and 0.3 g of DI-7020 (a nonionic surfactant, manufactured by Kao Corporation) were added, and the sample was lightly pressed down with the stirring rod and immersed for 1 minute. Thereafter, the mixer was started and the mixture was pulverized at a rotation speed of 15,000 rpm for 3 minutes. Then, a water-moistened filter paper was attached to a Buchner funnel, and the contents of the mixer were filtered while being drawn with an aspirator to obtain a filtrate and a pulp mat. The obtained pulp mat was visually observed and the deinking property was evaluated. <Evaluation criteria> ○: No coloring ×: Coloring can be confirmed

[0059] (Examples 1 to 25, Comparative Example 1) Preparation of Inkjet Ink 1 The above colorant, solvent, binder resin, surfactant, and water were mixed to prepare an inkjet ink. The inkjet inks were then evaluated. The results are shown in Tables 2 and 3.

[0060] [Table 2]

[0061] [Table 3]

[0062] It was confirmed from Examples 1 to 25 and Comparative Example 1 that the ink-jet inks containing the specified colorants were excellent in ejection properties and deinking properties.

[0063] (Examples 26 to 32, Comparative Example 2) Preparation of Inkjet Ink 2 In addition, after examining the composition of each inkjet ink, the above-mentioned colorant, solvent, binder resin, surfactant, and water were mixed to produce the inkjet ink. The ink-jet ink was evaluated and found to have excellent ejection and deinking properties. The results are shown in Tables 4 and 5. In the tables, "other components" refers to components other than the pigment contained in the colorant.

[0064] [Table 4]

[0065] [Table 5] [Industrial Applicability]

[0066] The inkjet ink of the present invention has a reduced environmental impact and is easy to deink, so that recycling is expected. The ink-jet ink of the present invention is also useful as an ink-jet ink for food, for example.

Claims

1. 1. An ink-jet ink comprising a pigment, The ink-jet ink is characterized in that the colorant is one or more selected from the group consisting of iron oxide compounds, phycocyanin, caramel, copper chlorophyllins, capsaicin, carminic acid, betanin, cyanidin glycosides, carmine, β-carotene, lutein, norbixin, and curcumin.

2. The iron oxide compound is triiron tetroxide (Fe ３ O ４ ), iron trioxide (Fe ２ O ３ 2. The ink-jet ink according to claim 1, wherein the inorganic filler is one or more selected from the group consisting of iron oxyhydroxide (FeOOH) and iron oxyhydroxide (FeOOH).

3. The ink-jet ink according to claim 1 or 2, further comprising a solvent.

4. The ink-jet ink according to claim 1 or 2, further comprising a binder resin.

5. The ink-jet ink according to claim 1 or 2, further comprising a surfactant.

6. The ink-jet ink according to claim 1 or 2, further comprising water.

7. 3. The ink-jet ink according to claim 1, which is used for food, cardboard, food packaging or textile applications.

8. An ink set comprising the inkjet ink according to claim 1 or 2.

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