ink

Abstract

To provide an inkjet printing ink that exhibits excellent redispersibility, color development, and abrasion resistance in printed materials. [Solution] An ink containing an anionic crosslinking agent, sugar alcohol, and water.

Description

Technical Field

[0001] The present invention relates to an ink and an inkjet recording method using the ink set.

Background Art

[0002] With the progress of digitalization of information, inkjet recording has become widely popular as an office and home printing method. In recent years, many applications have also been developed for commercial printing, printing on fibers, etc. As the uses of inkjet recording expand, the colorants used in inkjet inks have changed from conventional water-soluble dyes such as acid dyes or reactive dyes to water-insoluble colorants according to the application, that is, various colorants such as disperse dyes and pigments are now used.

[0003] Examples of inkjet inks using pigments include the ink of Patent Document 1. This is a dispersion ink composition using a polymer dispersant. In recent years, a method of mixing a resin into the ink and curing and fixing it to the recording material by heat treatment is also known, and is disclosed in, for example, Patent Documents 2 and 3.

[0004] In inkjet recording using pigments, "bleeding" and "decrease in color development" on the recording material have been problems. Regarding this problem, it has been proposed to perform pretreatment on the recording material. For example, such treatment liquids are proposed in Patent Documents 4 and 5 below.

[0005] On the other hand, when pretreatment is performed, there are problems such as the "trace" of the pretreatment solution remaining on the fibers in the areas where the pretreatment solution was applied, and discoloration such as yellowing occurring over time. In addition, variations in the pretreatment process can easily lead to uneven density in printed materials, which is also a problem. For the reasons above, there is a strong demand for inkjet inks that can achieve high color development and fastness (lightfastness, abrasion resistance, and water and wash resistance, etc.) without pretreatment. In particular, high color development is required for black ink, which requires a high pigment concentration in the ink. However, an increase in the solid content in the ink makes it difficult to redisperse the ink when it solidifies, which can lead to problems such as uneven ejection and nozzle breakage in continuous printing. To suppress this, there is a need for inks that can be easily redispersed even when solidified, i.e., high redispersibility. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 3534395 [Patent Document 2] Japanese Patent Publication No. 2011-246633 [Patent Document 3] Japanese Patent Application Publication No. 9-143407 [Patent Document 4] Japanese Patent Application Publication No. 07-119047 [Patent Document 5] Japanese Patent Publication No. 2000-226781 [Patent Document 6] Japanese Patent Publication No. 2006-150694 [Patent Document 7] Japanese Patent Publication No. 2021-154610 [Patent Document 8] Japanese Patent Publication No. 2020-105481 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The object of this invention is to provide an inkjet printing ink that exhibits excellent redispersibility and superior color development and abrasion resistance in printed materials. [Means for solving the problem]

[0008] 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.

[0009] 1) An ink containing an anionic crosslinking agent, sugar alcohol, and water. 2) The ink according to 1), wherein the total mass content of the sugar alcohol in the ink exceeds 10% by mass and is 20% by mass or less. 3) Furthermore, the ink described in 1) or 2), which also contains resin. 4) The ink described in 3), wherein the above resin includes urethane resin. 5) An ink set including one of the inks listed in item 1) to 4) and other inks. 6) The above-mentioned other inks include a white pigment, as described in 5) the ink set. 7) A method for manufacturing an inkjet printed material, comprising ejecting droplets of ink described in any one of items 1) to 4) from an inkjet head and adhering them to a printing medium to obtain a printed material. [Effects of the Invention]

[0010] The present invention provides an inkjet printing ink, an inkjet recording method, a printing medium, and a printing medium set that exhibit excellent redispersibility and superior color development and abrasion resistance in printed materials. [Modes for carrying out the invention]

[0011] The present invention will be described in detail below. In this specification, unless otherwise specified, "parts" and "%", including those in examples, etc., are all described on a mass basis.

[0012] The above ink contains an anionic crosslinking agent, a sugar alcohol, and water.

[0013] [Anionic crosslinking agent] The above anionic crosslinking agent refers to a crosslinking agent having an anionic group. The anionic group is not particularly limited as long as it is an anionic substituent, and examples thereof include a carboxy group, a sulfonic acid group, and a phosphonic acid group. By using a crosslinking agent having an anionic group, good redispersibility can be obtained even when the ink dries and solidifies. The anionic crosslinking agent is not particularly limited as long as it has a crosslinking ability with a carboxy group and a hydroxy group. Examples thereof include a blocked isocyanate group-containing compound, a compound having an epoxy group, a compound having an oxazoline group, a compound having a carbodiimide group, a compound having a methylol group, a compound having a cyclocarbonate group, a compound having an azirynyl group, a compound having an acetoacetyl group, a compound having a silanol group, and the like. These may be used alone or in combination of two or more. Among these, a blocked isocyanate group-containing compound and a compound containing an epoxy group are preferable, and a blocked isocyanate group-containing compound is more preferable. Also, it may be a water-soluble compound or a water-dispersible compound, but from the viewpoint of storage stability, it is preferably a water-dispersible compound. In the present invention, the "blocked isocyanate group-containing compound" represents a compound in which the isocyanate group in a polyisocyanate compound is blocked with a blocking agent.

[0014] The above-mentioned blocked isocyanate group-containing compounds represent compounds in which the isocyanate groups in a polyisocyanate compound are blocked by a blocking agent. Because the highly reactive isocyanate groups are blocked, the isocyanate groups are stabilized, thereby improving the storage stability of aqueous compositions and enabling the formation of a strong ink film after the crosslinking reaction. Polyisocyanate compounds are compounds having two or more isocyanate groups in one molecule, and examples of such polyisocyanate compounds include aliphatic isocyanates, alicyclic isocyanates, aromatic aliphatic isocyanates, aromatic isocyanates, etc., and modified versions thereof. Modified versions of polyisocyanate compounds include polymers such as isocyanurates; biuret compounds; and adduct compounds with polyhydric alcohols such as trimethylolpropane and pentaerythritol.

[0015] As the above aliphatic isocyanate, for example, a diisocyanate having a linear or branched aliphatic hydrocarbon group between two isocyanate groups is preferred. The number of carbon atoms in the aliphatic hydrocarbon group is preferably 2 or more, more preferably 3 or more, and preferably 10 or less, more preferably 9 or less, and even more preferably 8 or less. Specifically, examples include tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (HDI), heptamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4- or 2,4,4-trimethylhexamethylene diisocyanate, and the like. Examples of the above-mentioned alicyclic isocyanates include hydrogenated xylylene diisocyanate (H6XDI), 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate (H12MDI), isophorone diisocyanate (IPDI), and 2,5- or 2,6-norbornane diisocyanate. Examples of the above-mentioned aromatic aliphatic isocyanates include m- or p-xylylene diisocyanate (XDI) and tetramethylxylylene diisocyanate (TMXDI). Examples of the above aromatic isocyanates include 1,3- or 1,4-phenylenediisocyanate, 2,4- or 2,6-tolylenediisocyanate (TDI), 4,4'- or 2,4'-diphenylmethanediisocyanate (MDI), m- or p-isocyanatophenylsulfonyl isocyanate, 4,4'-diisocyanatobiphenyl, 4,4'-diisocyanate-3,3'-dimethylbiphenyl, 1,5-naphthylenediisocyanate, and 2,6-dimethylbenzene-1,4-diisocyanate.

[0016] Examples of the blocking agents mentioned above include amines such as 3,5-dimethylpyrazole (DMP), 1,2,4-triazole, and diisopropylamine; phenols such as phenol and cresol; oximes such as methyl ethyl ketoxime; lactams such as ε-caprolactam; and compounds having active hydrogen such as active methylene compounds such as diethyl malonate and ethyl acetoacetate. Among these, 3,5-dimethylpyrazole (DMP) is preferred from the viewpoint of stability, resistance to yellowing, and safety.

[0017] The dissociation temperature of the above-mentioned block-type isocyanate group-containing compound is preferably 120°C or higher, more preferably 125°C or higher, from the viewpoint of storage stability, friction fastness, and adhesion. When the temperature is 120°C or higher, the storage stability of the above-mentioned ink composition tends to improve. Furthermore, from the viewpoint of suppressing damage such as deformation of the recording medium, the temperature is preferably 150°C or lower, more preferably 130°C or lower. In particular, when polyester or polyester-containing blended fibers are used as the recording material, it is necessary to carry out the drying process after printing at a drying temperature of 130°C or lower in order to prevent dye migration (hereinafter also simply referred to as color transfer), so it is preferable that the dissociation temperature be 130°C or lower.

[0018] Examples of commercially available anionic blocked isocyanate group-containing compounds include Bayhydur BL2781 (manufactured by Sumika Covestro Urethane Co., Ltd., trade name); Trixene blocked isocyanates Aqua BI201 (manufactured by Lanxess, trade name); Meikanate SU-268A (manufactured by Meisei Chemical Industry Co., Ltd., trade name); and Elastron BN-27 and BN-77 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name).

[0019] The total mass of the active ingredient of the anionic crosslinking agent in the above ink is preferably in the range of 0.1% to 4.0% by mass, more preferably in the range of 0.2% to 3.5% by mass, even more preferably in the range of 0.3% to 3.0% by mass, particularly preferably in the range of 0.4% to 2.5% by mass, especially preferably in the range of 1% to 2.5% by mass, and extremely preferably in the range of 1.5% to 2.2% by mass.

[0020] [Sugar alcohols] The sugar alcohols mentioned above refer to compounds formed by reducing sugar compounds (e.g., aldoses and ketoses). Because sugar alcohols have numerous hydroxyl groups, they exhibit excellent solubility in water. Sugar alcohols have a melting point above 25°C at 1 atmosphere. Therefore, sugar alcohols are solid at room temperature (25°C). The melting point of sugar alcohols is usually between 25°C and 270°C, preferably between 50°C and 250°C, more preferably between 50°C and 200°C, even more preferably between 50°C and 170°C, and particularly preferably between 50°C and 150°C. By using sugar alcohols within this melting point range, images with excellent fixability, drying properties, scratch resistance, and transfer resistance tend to be obtained. Examples of sugar alcohols include treitol (melting point: 88-90°C), erythritol (melting point: 121°C), arabitol (melting point: 103°C), ribitol (melting point: 102°C), xylitol (melting point: 92-96°C), sorbitol (glucitol) (melting point: 95°C), mannitol (melting point: 164-169°C), iditol (melting point: 75-79°C), galactitol (melting point: 186-191°C), allitol (melting point: 150-154°C), maltitol (melting point: 145°C), isomaltitol (melting point: 98-103°C), lactitol (melting point: 146°C), and pentaerythritol (melting point: 190-263°C). Among these, sugar alcohols with hygroscopic properties are preferred. Sugar alcohols that absorb 0.5 wt% or more of moisture at 25°C and 50% relative humidity are preferred, and sugar alcohols that absorb 1.0 wt% or more of moisture are more preferred. Among these, sorbitol (glucitol) is preferred. Note that sugar alcohols may contain sugar compounds (such as glucose) before reduction as impurities.

[0021] The total mass of the sugar alcohol in the above ink is preferably in the range of 7% by mass or more and 25% by mass or less, more preferably in the range of more than 10% by mass and 20% by mass or less, and even more preferably in the range of 12% by mass or more and 18% by mass or less.

[0022] The above-mentioned anionic crosslinking agent and the above-mentioned sugar alcohol can be used in any ratio. By changing the ratio of the above-mentioned anionic crosslinking agent to the above-mentioned sugar alcohol, it is possible to improve the redispersibility, abrasion resistance of printed materials, and even the color development. In the above ink, if A is the total mass of the active ingredient of the anionic crosslinking agent and B is the total mass of the sugar alcohol, and the ratio is expressed as "B / A", then it is preferable that the value is in the range of 2 to 13, more preferably in the range of 3 to 12, even more preferably in the range of 5 to 11, and particularly preferably in the range of 6 to 10.

[0023] [water] The above ink contains water. Preferably, the water used is water with a low content of impurities such as metal ions, i.e., ion-exchanged water or distilled water. 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 composition to a suitable range, it is usually 30% to 70% by mass, preferably 35% to 65% by mass, and more preferably 40% to 60% by mass, based on the total mass (100% by mass) of the ink composition.

[0024] The above ink may also contain resin in addition to the above components. Examples of the above-mentioned resins include urethane resins, styrene-butadiene resins, polyester resins, acrylic resins, vinyl acetate resins, vinyl chloride resins, acrylic styrene resins, and acrylic silicone resins. Commercially available products include, for example, Permarin UA-150, 200, 310, 368, 3945, U-Coat UX-320, 390 (all manufactured by Sanyo Chemical Industries, Ltd.); Superflex 126, 150, 170, 210, 420, 470, 500M, 740, 820, 830, 860, 890 (all urethane resin emulsions manufactured by Daiichi Kogyo Seiyaku Co., Ltd.); Hydran WH-350, WH-178, WH-163, WH-171, AP-20, AP-30, AP-40F, WLS-201, WLS-210, WLS-213, WLS-221, WLS-230, WLS-250 (all urethane resin emulsions manufactured by DIC Corporation); ETERNACOLL UW-1005N, UW-1013D, UW-1501F, UW-1527F, UW-5002 (all product names manufactured by Ube Industries); Takelac WS-4000, WS-5000, WS-5030, WS-5100, WS-5130, W-6061, W-6110, WS-5984 (all product names manufactured by Mitsui Chemicals); 0568, 0569, 0850Z, 2108 (all styrene-butadiene resin emulsions manufactured by JSR Corporation); AE980, AE981A, AE982, AE986B, AE104 (all acrylic resin emulsions manufactured by E-Tech Co., Ltd.); Saibinol SK-200 (acrylic resin emulsion manufactured by Saiden Chemical Co., Ltd.); Boncoat Examples include 4001, 5454 (acrylic resin emulsions manufactured by DIC Corporation), and it is preferable that the above resin includes a urethane resin, and it is more preferable that the above resin consists of a urethane resin.

[0025] Examples of the above-mentioned urethane resins include polyether-type urethane resins containing ether bonds in the main chain, polyester-type urethane resins containing ester bonds in the main chain, and polycarbonate-type urethane resins containing carbonate bonds in the main chain, in addition to urethane bonds. Multiple types of these urethane resins can be used in combination. Among these, from the viewpoint of improving friction fastness, it is preferable to include polyester-type urethane resin and polycarbonate-type urethane resin, and it is even more preferable to use polyester-type urethane resin and polycarbonate-type urethane resin in combination. Examples of polyester-type urethane resins include Superflex 210, 500M, 740; Takelac WS-4000, WS-5000, WS-5030, WS-5130, WS-5984; and others. Examples of polycarbonate-type urethane resins include Permarine UA-310, 3945; U-Coat UX-320; Hydran WLS-210, 213, 250; Takelac W-6110; and others. If the above ink contains the above resin, the total content (active ingredient) is preferably 3% by mass or more and 30% by mass or less, more preferably 7% by mass or more and 25% by mass or less, and even more preferably 10% by mass or more and 20% by mass or less. Furthermore, when the above ink uses both polyester-type urethane resin and polycarbonate-type urethane resin, it is preferable that the mass content of polyester-type urethane resin in the ink is greater than the mass content of polycarbonate-type urethane resin. If the mass content of polyester-type urethane resin is W1 and the mass content of polycarbonate-type urethane resin is W2, then the value obtained by W1 / W2 is preferably greater than 1 and 4 or less, more preferably between 1.2 and 3, and even more preferably between 1.5 and 2.5.

[0026] The above ink may also contain colorants in addition to the above components. As colorants, for example, pigments, disperse dyes, solvent dyes, etc., can be used. These colorants may be used individually or in combination of two or more types. Furthermore, two or more colorants with different hues may be used in combination for purposes such as adjusting the hue. From the viewpoint of image fastness, such as lightfastness and water resistance of the recorded image, pigments are preferred as colorants, and inorganic pigments, organic pigments, or extender pigments are preferred as pigments.

[0027] Examples of the inorganic pigments mentioned above include carbon black, white pigments, metal oxides, hydroxides, sulfides, ferrocyanides, and metal chlorides. Preferred black pigments for the black ink include carbon blacks (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black, or metals such as copper chromite (CI Pigment Black 28), iron oxide (CI Pigment Black 11), and titanium oxide.Specific examples of carbon black include, for example, Raven 760 ULTRA, Raven 780 ULTRA, Raven 790 ULTRA, Raven 1060 ULTRA, Raven 1080 ULTRA, Raven 1170, Raven 1190 ULTRA II, Raven 1200, Raven 1250, Raven 1255, Raven 1500, Raven 2000, Raven 2500ULTRA, Raven 3500, Raven 5000 ULTRA II, Raven 5250, Raven 5750, Raven 7000 (manufactured by Columbia Carbon); Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, and Regal 1330R, Regal 1400R, Regal 1660R, Mogul L (manufactured by Cabot); Color Black FW1, Color Black FW2, Color Black FW2V, Color Black FW200, Color Black S150, Color Black S160, Color Black S170, Printex 35, Printex U, Printex V, Printex 140U, Printex 140V, SpecIal Black 4, SpecIal Black 4A, SpecIal Black 5, Special Black Examples include 6. Nerox305, Nerox505, Nerox510, Nerox600, Nerox605, Nerox2500, Nerox3500, NIPex180IQ, NIPex170IQ, NIPex160IQ, NIPex150IQ (manufactured by Orion Engineered Carbons); MA7, MA8, MA100, MA600, MCF-88, No.25, No.33, No.40, No.47, No.52, No.900, No.2300 (manufactured by Mitsubishi Chemical Corporation).

[0028] Examples of the above organic pigments include azo, disazo, phthalocyanine, quinacridone, isoindolinone, dioxazine, perylene, perinone, thioindigo, antholaquinone, and quinophthalone. Specific examples of organic pigments include CI Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 24, 55, 73, 74, 75, 83, 93, 94, 95, 97, 98, 108, 114, 128, 129, 138, 139, 150, 151, 154, 155, 180, 185, 193, 199, 202, 213, etc.; CI Pigment Red Reds such as 5, 7, 12, 48, 48:1, 57, 88, 112, 122, 123, 146, 149, 150, 166, 168, 177, 178, 179, 184, 185, 202, 206, 207, 254, 255, 257, 260, 264, 272; CI Pigment Blues such as 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 22, 25, 60, 66, 80; CI Pigment Violets such as 19, 23, 29, 37, 38, 50; CI Pigment Oranges such as 13, 16, 68, 69, 71, 73; CI Pigment Green Examples of organic pigments include greens such as 7, 36, and 54; and blacks such as CI Pigment Black 1.

[0029] When using the above-mentioned pigments as colorants, one type of pigment may be used, or two or more types of pigments may be used in combination. Furthermore, two or more pigments with different hues may be used in combination for purposes such as adjusting the hue. When using two or more pigments in combination, the mixing ratio between the pigments may be adjusted according to the purpose.

[0030] The above ink is preferably a black ink containing a black pigment. Preferred black pigments include carbon black (CI Pigment Black 7), or metals such as copper chromite (CI Pigment Black 28), iron oxide (CI Pigment Black 11), and titanium oxide, as well as CI Pigment Black 1. It is also preferable that the black ink is a blend of two or more pigments with different hues to achieve a black color. By including the above anionic crosslinking agent and the above sugar alcohol in the above black ink, particularly high color development and good abrasive properties tend to be obtained.

[0031] The content of the above-mentioned colorants relative to the total mass of the above-mentioned ink is usually 0.5% by mass or more and 20.0% by mass or less, with a preference of 1.0% by mass or more and 10.0% by mass or less, more preferably 2.0% by mass or more and 8.0% by mass or less, even more preferably 3.0% by mass or more and 7.0% by mass or less, and particularly preferably 3.5% by mass or more and 6.5% by mass or less. The content of the white pigment is usually 1.0% by mass or more and 20% by mass or less, with a preference of 2.0% by mass or more and 18% by mass or less, even more preferably 3.0% by mass or more and 16% by mass or less, and most preferably 5.0% by mass or more and 14% by mass or less.

[0032] By setting the content of the above-mentioned colorant relative to the total mass of the above-mentioned ink to the above-mentioned range, the storage stability of the ink, its ability to dry and redisperse, its print stability, and the color development, abrasion resistance, and dot diameter of the printed material can be further improved.

[0033] The above ink may further contain ink preparations in addition to the components described above. Examples of ink preparations include water-soluble organic solvents, surfactants, viscosity modifiers, defoamers, preservatives, pH adjusters, rust inhibitors, dispersants, and lubricants.

[0034] There are no particular limitations on water-soluble organic solvents as long as they contain carbon atoms in their molecules, but specific examples include C1-C6 alkanols such as propanol, isopropanol, butanol, isobutanol, derbutanol, and tertbutanol; 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 cyclic solvents such as 1,3-dimethylimidazolidin-2-one and 1,3-dimethylhexahydropyrimido-2-one. Urea compounds; ketones or keto alcohols such as acetone, 2-methyl-2-hydroxypentan-4-one, and ethylene carbonate; cyclic ethers such as tetrahydrofuran and dioxane; ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butylene glycol, 1,4-butylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, polyethylene glycol (preferably with a molecular weight of 400, 800, 1540 or higher), polypropylene Mono, oligo, or polyalkylene glycols or thioglycols having C2-C6 alkylene units such as thioglycol, thiodiglycol, and dithiodiglycol; 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 monobutyl 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, proylene 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, 1,3-propanediol, triethylene glycol, 3-methyl-1,3-butanediol, 1,6-hexanediol, glycerin, diethylene glycol monobutyl ether, and propylene glycol monopropyl ether, and it is more preferable to contain 1,2-propanediol, 1,3-propanediol, 3-methyl-1,3-butanediol, 1,6-hexanediol, glycerin, and propylene glycol monopropyl ether.

[0035] Furthermore, the total content of the above-mentioned water-soluble organic solvent is preferably 3% by mass or more and 20% by mass or less, more preferably 5% by mass or more and 15% by mass or less, and even more preferably 6% by mass or more and 12% by mass or less.

[0036] 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.

[0037] 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 TMLA-10, LA-12, LA-16, Neo Hytenol TMECL-30S, and ECL-45, all manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

[0038] Examples of the cationic surfactants mentioned above include 2-vinylpyridine derivatives and poly-4-vinylpyridine derivatives.

[0039] 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, and polyoxyethylene alkyl ether; and polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, and polyoxyethylene monooleate. Examples include esters such as 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; Surfinol™104, 104PG50, 105PG50, 82, 420, 440, 465, and 485, all manufactured by Nisshin Chemical Industry Co., Ltd.; Olphine™STG; and polyglycol ether compounds (for example, TergItol™15-S-7, manufactured by SIGMA-ALDRICH).

[0040] 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.

[0041] 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.).

[0042] 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).

[0043] Among the above, nonionic and silicone-based surfactants are preferred. These surfactants may be used individually or in combination of two or more. When the above ink contains a surfactant, the total surfactant content is typically 0.05% to 5% by mass, preferably 0.07% to 4% by mass, more preferably 0.1% to 3% by mass, and even more preferably 0.15% to 1% by mass, relative to the total mass of the ink. By using a surfactant within the above range in the ink, the penetration into the substrate and the dispersion stability of the colorant in the ink can be improved.

[0044] The viscosity modifier is not particularly limited as long as it is a substance other than the components mentioned above that can adjust the viscosity of the water-based ink composition, and any known substance can be used. Specific examples include, for example, water-soluble polymer compounds, which will be discussed later.

[0045] Examples of defoaming agents include silicone-based, silica mineral oil-based, olefin-based, and acetylene-based compounds. Examples of commercially available products include Surfinol DF37, DF58, DF110D, DF220, MD-20, and Olfin SK-14 (all manufactured by Nisshin Chemical Industry Co., Ltd.); BYK-1719, BYK-1724, and BYK-1770 (all manufactured by Big Chemie Co., Ltd.). 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 dispersion stability.

[0046] Examples of preservatives include compounds such as organic sulfur, organic nitrogen sulfur, organic halogen, haloaryl sulfone, iodopropagyl, haloalkylthio, nitrile, pyridine, 8-oxyquinoline, benzothiazole, isothiazolin, dithiol, pyridine oxide, nitropropane, organotin, phenol, quaternary ammonium salt, triazine, thiazine, anilide, adamantane, dithiocarbamate, brominated indanone, benzyl bromacetate, and inorganic salts. Specific examples of organic halogen compounds include, for example, sodium pentachlorophenol. Specific examples of pyridine oxide compounds include, for example, sodium 2-pyridinethiol-1-oxide. Specific examples of isothiazolin compounds include, for example, 1,2-benzisothiazolin-3-one, 2-n-octyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one magnesium chloride, 5-chloro-2-methyl-4-isothiazolin-3-one calcium chloride, and 2-methyl-4-isothiazolin-3-one calcium chloride. Specific examples of other preservatives and fungicides include, for example, anhydrous sodium acetate, sodium sorbate, sodium benzoate; Proxel GXL(S), Proxel XL-2(S) (both manufactured by Arxada Corporation); and others.

[0047] 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.

[0048] Examples of the above-mentioned rust inhibitors include acidic sulfites, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitride, pentaerythritol tetranitrate, or dicyclohexylammonium nitride.

[0049] The above dispersant is not particularly limited, and known dispersants can be used. Known dispersants include, for example, copolymers composed of at least two monomers (preferably at least one of which is hydrophilic) selected from monomers of the group consisting of styrene and its derivatives; vinylnaphthalene and its derivatives; aliphatic alcohol esters of α,β-ethylenically unsaturated carboxylic acids; acrylic acid and its derivatives; maleic acid and its derivatives; itaconic acid and its derivatives; fahric acid and its derivatives; vinyl acetate, vinyl alcohol, vinylpyrrolidone, acrylamide, and their derivatives. Examples of such copolymers include styrene-(meth)acrylic acid copolymer, styrene-(meth)acrylic acid-(meth)acrylic acid ester copolymer, (meth)acrylic acid ester-(meth)acrylic acid copolymer, polyethylene glycol (meth)acrylate-(meth)acrylic acid copolymer, styrene-maleic acid copolymer, and the like.

[0050] Among these, styrene-(meth)acrylic acid copolymer, styrene-(meth)acrylic acid-(meth)acrylic acid ester copolymer, (meth)acrylic acid ester-(meth)acrylic acid copolymer, and polyethylene glycol (meth)acrylate-(meth)acrylic acid copolymer are preferred; styrene-(meth)acrylic acid copolymer, styrene-(meth)acrylic acid-(meth)acrylic acid ester copolymer, and (meth)acrylic acid ester-(meth)acrylic acid copolymer are more preferred; (meth)acrylic acid ester-(meth)acrylic acid copolymer is even more preferred; and methacrylic acid ester-methacrylic acid copolymer is particularly preferred.

[0051] Examples of copolymer types include block copolymers, random copolymers, graft copolymers, and / or salts thereof, with block copolymers being preferred.

[0052] Dispersants can be synthesized or obtained commercially. Specific examples of commercially available dispersants include styrene-acrylic copolymers such as Joncryl 62, 67, 68, 678, and 687, all manufactured by BASF; Movinyl S-100A (modified vinyl acetate copolymer manufactured by Hoechst Synthetic Co., Ltd.); and Jurimer AT-210 (polyacrylic acid ester copolymer manufactured by Nippon Junyaku Co., Ltd.). As a block copolymer obtained by synthesis, the AB block polymer disclosed in International Publication No. 2013 / 115071 is a preferred example. These dispersants may be used individually or in combination of two or more.

[0053] The lubricant should be one that imparts slipperiness to the surface of the image-forming object and enhances its abrasion resistance or frictional durability.

[0054] Examples of lubricants include wax emulsions and silicone emulsions. Among these, silicone emulsions are preferred from the viewpoint of drying and redispersibility.

[0055] Examples of the above-mentioned silicone emulsions include dimethyl silicone oil-based emulsions, amino group-containing silicone oil-based emulsions, epoxy group-containing silicone oil-based emulsions, mercapto group-containing silicone oil-based emulsions, and self-crosslinking silicone emulsions (emulsions that form rubber films). Among these, dimethyl silicone oil-based emulsions and self-crosslinking silicone emulsions (emulsions that form rubber films) are preferred. The above-mentioned silicone emulsion is preferably a silicone emulsion using an anionic surfactant. By using a silicone emulsion with an anionic surfactant, good redispersibility can be obtained even when the ink dries and solidifies. Examples of commercially available silicone emulsions include POLON-MN-ST, POLON-MF-33, POLON-MF-14, POLON-MF-14EC, POLON-MF-18T, KM-9769, KM-2002-T, KM-9772, KM-9749 (all product names from Shin-Etsu Chemical Co., Ltd.), WACKER E22, WACKER FINISH WT1270, WACKER FINISH WT1650, WACKER FINISH WR1100, WACKER FINISH WR1300, NP2406, NP2412, P2003, POWERSOFT FE 55, TS2007, and TS2406 (all product names from Asahi Kasei Corporation).

[0056] As the wax emulsion mentioned above, a water-based wax emulsion is preferred. As the waxing agent, natural waxes and synthetic waxes can be used. Examples of natural waxes include petroleum-based waxes such as paraffin wax and microcrystalline wax; lignite-based waxes such as montane wax; plant-based waxes such as carnauba wax and candelilla wax; and emulsions in which waxes such as beeswax and lanolin are dispersed in an aqueous medium. Examples of synthetic waxes include polyalkylene wax (preferably poly C2-C4 alkylene wax), oxidized polyalkylene wax (preferably oxidized poly C2-C4 alkylene wax), and paraffin wax. Of these, one or more waxes selected from polyethylene wax, polypropylene wax, oxidized polyethylene wax, oxidized polypropylene wax, and paraffin wax are preferred, with oxidized polyethylene wax being more preferred. The average particle size of the wax is 50 nm to 5 μm, and preferably 100 nm to 1 μm, in order to prevent clogging of the inkjet head. Examples of commercially available wax emulsions include AQUACER 515 (acid value: 5) manufactured by BIC Chemie Japan and HYTEC E-6500 (acid value: 10 to 20) manufactured by Toho Chemical Industry Co., Ltd. When the above ink composition contains the above lubricant, the proportion of the solid content of the above lubricant in the above ink composition is usually 0.1% to 5% by mass, preferably 0.2% to 3% by mass, more preferably 0.5% to 3% by mass, and even more preferably 0.7% to 2% by mass.

[0057] [Ink surface tension] The surface tension of the above ink at 25°C is preferably 25-48 mN / m, more preferably 28-44 mN / m, more preferably 30-42 mN / m, and particularly preferably 32-40 mN / m, from the viewpoint of achieving sufficient wettability for various printing media.

[0058] The surface tension of the above ink can be measured, for example, using a surface tensimeter (CBVPZ, manufactured by Kyowa Interface Science Co., Ltd.) by the platinum plate method at a temperature of 25°C.

[0059] [Ink viscosity] The viscosity of the above ink at 25°C is preferably 2 to 20 mPa·s, more preferably 3 to 18 mPa·s, and particularly preferably 4 to 15 mPa·s. Inks that meet the above viscosity range tend to have good ejection response in high-speed printing.

[0060] [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.

[0061] The above ink can be used in various printing applications. For example, it is suitable for various types of printing, information printing, and textile printing, and is particularly preferred for use in inkjet printing.

[0062] When preparing the above-mentioned ink, known manufacturing methods can be used. For example, one method involves preparing the ink by adding and mixing an anionic crosslinking agent, sugar alcohol, water, resin, colorant, and, if necessary, an ink preparing agent.

[0063] The above ink can be prepared using conventionally known equipment, such as a ball mill, sand mill, attritor, basket mill, roll mill, or agitator. During preparation, it is preferable to remove coarse particles using a membrane filter or mesh filter.

[0064] An ink set containing at least the above-mentioned ink is also included in the present invention. Examples of the above-mentioned ink sets include an ink set containing two 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, and it is even more preferable that they contain the above-mentioned white pigment.

[0065] The above ink and ink set are preferably used in inkjet printing.

[0066] The present invention also includes an inkjet recording method that includes the step of ejecting droplets of the above-mentioned ink and adhering them to a printing medium to form an image. Furthermore, 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 a printed material to which the above-mentioned ink has been applied.

[0067] When using the above ink for inkjet recording, it is preferable to remove aggregates and other contaminants by filtering the ink. Any known filtration method can be used as appropriate. For example, a method using suction filtration with filter paper such as glass filter paper GC-50 (retaining particle diameter 0.5 μm, manufactured by Advantec Co., Ltd.) or glass filter paper GA-100 (retaining particle diameter 1.0 μm, manufactured by Advantec Co., Ltd.) is possible.

[0068] The above-mentioned printing media refers to a medium (media) to which the above-mentioned ink can adhere, and can be broadly classified into those that absorb ink and those that do not absorb ink. Examples of ink-absorbing printing media include inkjet paper, inkjet film, glossy paper, corrugated cardboard, liner paper contained in corrugated cardboard, and fabrics. The above-mentioned fabrics include fibers and represent fabrics made from fibers in the form of woven, knitted, or nonwoven materials. Fibers that make up the fabrics include those selected from the group consisting of polyester, cellulose, polyamide, and natural fibers. Polyester fibers include those mainly composed of polyethylene terephthalate. Cellulose fibers include cotton, rayon, triacetate fibers, and diacetate fibers. Polyamide fibers include nylon fibers. Natural fibers include silk and wool. These fibers may be single-material fibers or blends thereof. Furthermore, these fibers may be provided with an ink-receiving layer (bleed-preventing layer).

[0069] The fabric colors can include all dark and light shades. Additionally, if necessary, a white ink composition can be applied to white fabric.

[0070] The above inkjet recording method involves ejecting droplets of each ink from the above ink set from an inkjet printer in accordance with a recording signal and adhering them to a printing medium to perform recording. There are no particular restrictions on the ink nozzles used during recording, and they can be appropriately selected according to the purpose.

[0071] Inkjet printers can use any known recording method. Examples include charge control methods that use electrostatic attraction to eject ink; drop-on-demand methods (pressure pulse methods) that use the vibration pressure of a piezoelectric element; acoustic inkjet methods that convert electrical signals into acoustic beams, irradiate ink onto it, and eject ink using the resulting radiation pressure; and thermal inkjet methods that heat the ink to form bubbles and utilize the resulting pressure. Furthermore, the inkjet recording method of the present invention also includes methods that improve the fixation of colorants by using colorless, transparent ink.

[0072] 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.

[0073] The above-described inkjet recording method is a method of recording using an inkjet printer having a container containing the above-described ink, and the inkjet recording method is preferably one in which the printing medium is selected from the group consisting of cloth, corrugated cardboard, liner paper, coated cardboard, and coated paper, more preferably cloth, corrugated cardboard, and liner paper, and particularly preferably cloth.

[0074] Unless otherwise specified, for all the matters mentioned above, a combination of preferred elements is more preferable, and a combination of preferred elements is 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 ingredients may be used individually or in combination of two or more elements.

[0075] The ink of the present invention exhibits excellent redispersibility, storage stability, and ejection reliability. Furthermore, images recorded with the above ink exhibit excellent color development, as well as various fastness properties such as water resistance, light resistance, oxidation gas resistance (e.g., ozone gas resistance), and abrasion resistance. In addition, it has excellent drying properties, coating unevenness, and bleeding during image formation, resulting in superior image formation performance. [Examples]

[0076] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples. Unless otherwise specified, the ink compositions were prepared under stirring. The "water" used in the examples is deionized water.

[0077] [Preparation Example 1]: Preparation of Dispersion 1 Polymeric dispersant A was obtained by replicating Synthesis Example 3 of International Publication No. 2013 / 115071. The acid value of the obtained polymeric dispersant A was 105 mgKOH / g, and the weight-average molecular weight was 25000. The obtained polymeric dispersant A (6.0 parts) was dissolved in 2-butanone (30.0 parts) to obtain a homogeneous solution. To this solution, 25% sodium hydroxide aqueous solution (1.8 parts), DF58 (0.6 parts), and deionized water (54.3 parts) were added, and the mixture was stirred for 1 hour to obtain an emulsion in which the polymeric dispersant was dissolved. To this emulsion, NEROX605 (20.0 parts, Orion Engineered Carbons) was added as a pigment, and after adding dispersion beads, the mixture was dispersed in a sand grinder under conditions of 1500 rpm for 15 hours. 55.0 parts of deionized water were added dropwise to the obtained solution, and the dispersion beads were removed by filtration. Then, 2-butanone and some of the water were removed under reduced pressure using an evaporator with a water bath temperature of 55°C to obtain dispersion 1 with a pigment solid content of 19.6%. The solid content in the aqueous solution was determined by the dry weight method using an MS-70 manufactured by A&D Co., Ltd. The average particle size (D50) of the pigment contained in dispersion 1 was 123 nm.

[0078] [Examples 1-6, Comparative Examples 1 and 2]: Ink Preparation Each ink composition was obtained by mixing the components listed in Table 1 below, stirring for approximately one hour, and then filtering through a 3 μm membrane filter. Each ink composition was prepared so that the pigment content in its total mass was 6%. Viscosity was measured using an E-type viscometer (TV-22, manufactured by Toki Sangyo Co., Ltd.). The abbreviations in Table 1 below represent the following: In Table 1, numbers represent "copies," and blank spaces indicate 0 copies. W-5130: Takelac W-5130 (manufactured by Mitsui Chemicals, active ingredient content 35%) W-6110: Takelac W-6110 (manufactured by Mitsui Chemicals, active ingredient content 32%) KM-9772: Silicone emulsion (manufactured by Shin-Etsu Chemical Co., Ltd., active ingredient content 40%) POLON-MN-ST: Silicone emulsion (manufactured by Shin-Etsu Chemical Co., Ltd., active ingredient content 31%) POLON-MF-33: Silicone emulsion (manufactured by Shin-Etsu Chemical Co., Ltd., active ingredient content 30%) Trixene Aqua BI 201: Blocked isocyanate group-containing compound (manufactured by Lanxess, active ingredient content 40%, ionic: anionic) Bayhydur BL2867: Blocked isocyanate group-containing compound (manufactured by Sumika Covestrourethane Co., Ltd., active ingredient content 38%, ionic: anionic) Trixene Aqua BI 220: Blocked isocyanate group-containing compound (manufactured by Lanxess, active ingredient content 40%, ionic: nonionic) GL: Glycerin Sorbitol: D-Sorbitol (manufactured by Tokyo Chemical Industry Co., Ltd.) SF420: Surfinol 420 TEA: Triethanolamine (manufactured by Junsei Chemical Co., Ltd.) GXL(S): PROXEL GXL(S) (Preservative, manufactured by Lonza Co., Ltd.)

[0079] [Preparation Example 2]: Preparation of White Ink The components listed in Table 2 below were thoroughly stirred and mixed to obtain a white ink. The obtained white ink was filtered through a 5 μm pore size mixed cellulose ester filter, and then degassed using a vacuum pump to obtain white ink W1 for printing evaluation. The values ​​in Table 2 below represent "parts". The abbreviations in Table 2 below represent the following: TF-5760: TF-5760 WHITE (D2B) (Titanium dioxide slurry manufactured by Dainichi Seika Kogyo Co., Ltd., titanium dioxide solid content concentration: 60%, average particle size: 300 nm) W-5130: Takelac W-5130 (manufactured by Mitsui Chemicals, active ingredient content 35%) W-6110: Takelac W-6110 (manufactured by Mitsui Chemicals, active ingredient content 32%) GL: Glycerin EXP-4001: Olfin EXP-4001 (manufactured by Nisshin Chemical Industry Co., Ltd.) TEA: Triethanolamine (manufactured by Junsei Chemical Co., Ltd.) GXL(S): PROXEL GXL(S) (Preservative, manufactured by Lonza Co., Ltd.)

[0080] [Table 1]

[0081] [Table 2]

[0082] [Redispersion Test] 5 ml each of the inks from the above examples and comparative examples was placed on a glass petri dish, spread thinly and evenly across the bottom of the dish, and the excess liquid was discarded. After drying in a 60°C dryer for 1 hour, 2 ml of deionized water was added dropwise at room temperature, and the redispersibility of the dried ink was visually evaluated on a four-point scale as described below. Substances that redisperse after drying return to a liquid state without leaving any residue, and can therefore be identified visually. The results are shown in Table 1 above. A: Redistribute everything completely, leaving no residue. B: A small amount of residue remains, but most of it has been redispersed. C: A large amount of residue remains, but it is somewhat redispersed. D: There is no redistribution at all.

[0083] [Preparation of printed materials (white cotton T-shirts) for evaluation] Each ink obtained above was ejected using an industrial inkjet evaluation device (expandable coating device EV2500: manufactured by Ricoh Co., Ltd.) to inkjet a solid black pattern image onto white cotton fabric (white cotton T-shirt, 00085-CVT heavyweight T-shirt (manufactured by PrintStar)). The ink coating amount at this time was 2.0 mg / cm². 2 Printing was performed with a print head temperature of 25°C. The resulting ink-coated cotton fabric was then subjected to a heat press treatment at 170°C for 1 minute to obtain each printed material (white cotton T-shirt) for evaluation. The following evaluation tests were performed on the evaluation printed materials obtained as described above.

[0084] [Evaluation of color development of white cotton T-shirts] Color reproduction was evaluated by measuring the Dk value of the evaluation print (white cotton T-shirt). An eXact colorimeter manufactured by X-Rite was used to measure the Dk value. The measurement conditions were: observation light source D65, observation field of view 2°, and density Status E. Five measurements were taken for each evaluation print, and the average value was used as the measurement result. Image density was evaluated according to the evaluation criteria below. The results are shown in Table 1 above. A: Dk value is 1.28 or higher B: Dk value is 1.25 or higher and less than 1.28 C:Dk value less than 1.25

[0085] [Abrasion fastness test of white cotton T-shirts] Each printed material (white cotton T-shirt) with the inks from Examples 1 to 6 obtained as described above was subjected to a colorfastness test against friction using a Type II (JSPS type) testing machine in accordance with the method specified in JIS L 0849. Dry friction was tested according to the drying test specified in JIS L 0849, and the judgment grade was evaluated using a stain grayscale. The colorfastness was evaluated according to the evaluation criteria below. The results are shown in Table 3 below. A: Judging grade is 4th-5th grade or higher B: Judging level is 4th grade C: Grade 3-4 D: Judging level is 3rd grade E: Judging grade is 2nd-3rd grade

[0086] [Preparation of pre-treated fibers] 182 parts by mass of DK-6804 (manufactured by Seikoh PMC, solids content 55% by mass), 66.7 parts by mass of Movinyl 6963 (manufactured by Japan Coating Resin, solids content 45% by mass), and 16 parts by mass of Epocross WS-700 (manufactured by Nippon Shokubai, solids content 25%) were mixed together. Then, water was added to make a uniform mixture with a weight solids content of 7% by mass to obtain a pretreatment solution. The obtained pretreatment solutions were each measured at 0.02 g / cm³. 2To achieve the desired amount of adhesion, a black cotton fabric (black cotton T-shirt, 00085-CVT heavyweight T-shirt (PrintStar)) was coated with a commercially available spray bottle (Takahashi Kasei Co., Ltd.: PET150BM Mist) to an A4 size. Subsequently, the fabric was heated and dried at 170°C for 60 seconds using a tabletop automatic flatbed press (Asahi Textile Machinery Co., Ltd.: AF-65TEN) to obtain pre-treated fibers. The following recording process was then performed.

[0087] [Preparation of print materials (black cotton T-shirts) for evaluation] The white ink W1 obtained in Preparation Example 2 was ejected onto the pre-treated portion of the pre-treated fibers obtained as described above using an industrial inkjet evaluation device (expandable coating device EV2500: manufactured by Ricoh Co., Ltd.) to record a solid white pattern image using inkjet technology. The ink application amount at this time was 18 mg / cm². 2 The print head temperature was recorded at 25°C. The ink application amount was 2.0 mg / cm² on a solid white pattern image. 2 Under the condition that the head temperature was 25°C, each of the inks from Examples 1 to 6 was ejected in the same manner to record a solid black pattern image using inkjet technology. The cotton fabric to which each of the inks from Examples 1 to 6 was applied was then subjected to a heat press at 170°C for 1 minute to obtain each printed material (black cotton T-shirt) for evaluation.

[0088] [Abrasion fastness test of black cotton T-shirts] For each printed sample (black cotton T-shirt) obtained as described above, a colorfastness test against friction was conducted using a Type II (JSPS type) testing machine in accordance with the method specified in JIS L 0849. Dry friction was tested according to the drying test specified in JIS L 0849, and the judgment grade was evaluated using a stain gray scale. The colorfastness was evaluated according to the evaluation criteria below. The results are shown in Table 3 below. A: Judging grade is 4th-5th grade or higher B: Judging level is 4th grade C: Grade 3-4 D: Judging level is 3rd grade E: Judging grade is 2nd-3rd grade

[0089] [Table 3]

[0090] From the results in Table 1 above, it can be seen that each ink in the examples exhibits remarkably excellent redispersibility, and that its color development (on a white cotton T-shirt) is equal to or better than that of the comparative example ink. Furthermore, from the results in Table 3 above, it can be seen that the example inks also possess high dry friction properties. [Industrial applicability]

[0091] To provide an inkjet printing ink that exhibits excellent redispersibility, color development, and abrasion resistance in printed materials.

Claims

1. An ink containing an anionic crosslinking agent, sugar alcohol, and water.

2. The ink according to claim 1, wherein the total mass content of the sugar alcohol in the ink is more than 10% by mass and 20% by mass or less.

3. The ink according to claim 1 or 2, further comprising a resin.

4. The ink according to claim 3, wherein the above resin includes a urethane resin.

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

6. The ink set according to claim 5, wherein the other inks mentioned above include a white pigment.

7. A method for manufacturing an inkjet printed material, comprising ejecting droplets of ink according to claim 1 or 2 from an inkjet head and adhering them to a printing medium to obtain a printed material.

Images