Inkjet ink, ink set, printing method, and printing apparatus

Abstract

An advantage of some aspects of the invention is to improve the rubbing fastness of a printed material when ink jet printing is performed on a fabric with an aqueous pigment ink.SOLUTION: An inkjet ink for printing on a textile, comprising water, an organic solvent, a pigment, and a urethane resin, wherein a glass transition temperature of a coating film obtained by drying the inkjet ink is - 65 °C or lower. The content of the urethane resin in 100% by mass of the ink jet ink is preferably 8% by mass or more to 15% by mass or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an inkjet ink, an ink set, a printing method, and a printing apparatus. [Background technology]

[0002] Inkjet printing has rapidly become popular in recent years due to its ability to easily record color images and its low running costs. It is also beginning to gain popularity in the field of textile printing, which has traditionally been done using analog methods centered on dyes. In particular, the use of aqueous pigment inks that use pigments as colorants can significantly reduce the amount of industrial wastewater generated by textile printing. Combined with the inventory reduction achieved by on-demand printing using inkjet printing, inkjet printing is known as an environmentally friendly printing method. In textile printing using aqueous pigment inks, color development, texture, and durability are key issues, and various companies are actively investigating these issues (see Patent Document 1).

[0003] It is also widely known that color development can be improved by preventing ink from penetrating into the fabric and fixing the ink components on the surface of the fabric, but on the other hand, the more the ink components are unevenly distributed on the surface of the fabric, the lower the durability. To address these issues, a method has been studied in which after printing the ink, a post-treatment containing a resin is applied to improve robustness (see Patent Document 2). However, there are issues such as the time and cost required for applying and drying the post-treatment liquid, and a means for improving fastness without post-treatment is desired. Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to improve the abrasion fastness of a printed matter when ink-jet printing is performed on fabric using an aqueous pigment ink. [Means for solving the problem]

[0005] The ink of the present invention, which is a means for solving this problem, is as described below. 1. An inkjet ink for printing on textiles, comprising: Contains water, organic solvents, pigments, and urethane resin. the glass transition temperature of the coating film obtained by drying the inkjet ink is −65° C. or lower; An inkjet ink characterized by: [Effects of the Invention]

[0006] According to the present invention, it is possible to improve the abrasion fastness of a printed matter when inkjet printing is performed on fabric using a water-based pigment ink. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing an example of a printing apparatus of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing an ink tank in the printing device of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] <Ink> The organic solvent, water, coloring material, resin, additives, etc. used in the ink will be described below.

[0009] <Urethane resin> The urethane resin is not particularly limited, but is preferably urethane resin particles from the viewpoint of low viscosity and storage stability. The urethane resin in the present invention is characterized by having a glass transition temperature (Tg) of −65° C. or lower from the viewpoint of improving fastness. The urethane resin is not particularly limited, and examples thereof include polyurethane resins obtained by reacting polyol with polyisocyanate. Examples of the polyol include polyether polyol, polycarbonate polyol, polyester polyol, etc. These may be used alone or in combination of two or more.

[0010] -Polyether polyol- Examples of the polyether polyol include those obtained by addition polymerization of alkylene oxide with one or more compounds having two or more active hydrogen atoms as a starting material.

[0011] Examples of the starting materials include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, glycerin, trimethylolethane, trimethylolpropane, etc. These may be used alone or in combination of two or more.

[0012] Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, etc. These may be used alone or in combination of two or more.

[0013] Examples of the polyether polyol include polyoxytetramethylene glycol, polyoxypropylene glycol, etc., which can provide an ink binder that can impart excellent abrasion resistance. These may be used alone or in combination of two or more.

[0014] -Polycarbonate polyol- Examples of polycarbonate polyols that can be used in producing the polyurethane resin include those obtained by reacting a carbonate ester with a polyol, and those obtained by reacting phosgene with bisphenol A. These may be used alone or in combination of two or more.

[0015] Examples of the carbonate ester include methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, diphenyl carbonate, etc. These may be used alone or in combination of two or more.

[0016] Examples of the polyol include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 2,5-hexanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1, Examples of such compounds include relatively low molecular weight dihydroxy compounds such as 11-undecanediol, 1,12-dodecanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, hydroquinone, resorcinol, bisphenol-A, bisphenol-F, and 4,4'-biphenol, polyether polyols such as polyethylene glycol, polypropylene glycol, and polyoxytetramethylene glycol, and polyester polyols such as polyhexamethylene adipate, polyhexamethylene succinate, and polycaprolactone. These may be used alone or in combination of two or more.

[0017] -Polyester polyol- Examples of the polyester polyol include those obtained by esterifying a low-molecular-weight polyol with a polycarboxylic acid, polyesters obtained by ring-opening polymerization of a cyclic ester compound such as ε-caprolactone, copolymerized polyesters thereof, etc. These may be used alone or in combination of two or more.

[0018] Examples of the low molecular weight polyol include ethylene glycol, propylene glycol, etc. These may be used alone or in combination of two or more. Examples of the polycarboxylic acid include succinic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, anhydrides or ester-forming derivatives thereof, etc. These may be used alone or in combination of two or more.

[0019] -Polyisocyanate- Examples of the polyisocyanate include aromatic diisocyanates such as phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, and naphthalene diisocyanate; and aliphatic or alicyclic diisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, and 2,2,4-trimethylhexamethylene diisocyanate. These may be used alone or in combination of two or more.

[0020] [Method of manufacturing polyurethane resin] The polyurethane resin used in the ink of the present invention can be obtained by a conventionally used production method, for example, the following method. First, the polyol and the polyisocyanate are reacted in the absence of a solvent or in the presence of an organic solvent at an equivalent ratio such that the isocyanate group is in excess to produce an isocyanate-terminated urethane prepolymer. Next, the anionic groups in the isocyanate-terminated urethane prepolymer are neutralized with a neutralizing agent as needed, followed by reaction with a chain extender, and finally, the organic solvent in the system is removed as needed to obtain the polymer.

[0021] Examples of organic solvents that can be used in producing polyurethane resins include ketones such as acetone and methyl ethyl ketone, ethers such as tetrahydrofuran and dioxane, acetates such as ethyl acetate and butyl acetate, nitriles such as acetonitrile, amides such as dimethylformamide, N-methylpyrrolidone and N-ethylpyrrolidone, etc. These may be used alone or in combination of two or more. Examples of the chain extender include polyamines and other active hydrogen group-containing compounds, which may be used alone or in combination of two or more.

[0022] Examples of the polyamine include diamines such as ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4'-dicyclohexylmethanediamine, and 1,4-cyclohexanediamine; polyamines such as diethylenetriamine, dipropylenetriamine, and triethylenetetramine; hydrazines such as hydrazine, N,N'-dimethylhydrazine, and 1,6-hexamethylenebishydrazine; and dihydrazides such as succinic acid dihydrazide, adipic acid dihydrazide, glutaric acid dihydrazide, sebacic acid dihydrazide, and isophthalic acid dihydrazide. These may be used alone or in combination of two or more.

[0023] Examples of the other active hydrogen group-containing compounds include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, sucrose, methylene glycol, glycerin, and sorbitol; phenols such as bisphenol A, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, hydrogenated bisphenol A, and hydroquinone; and water. These may be used alone or in combination of two or more types, as long as the storage stability of the ink is not reduced.

[0024] As described above, the urethane resin in the present invention is characterized by having a glass transition temperature (Tg) of −65° C. or lower. As the urethane resin having a Tg of −65° C. or lower, a commercially available product can be used, and examples of the commercially available product include Hydran WLS-202 (Tg=−68° C., manufactured by DIC Corporation) and Hydran WLS-230 (Tg=−75° C., manufactured by DIC Corporation). These may be used alone or in combination of two or more. The glass transition temperature of the urethane resin is approximately equal to the glass transition temperature of the coating film obtained by drying the inkjet ink. Therefore, in the present invention, it is a constituent requirement that the glass transition temperature of the coating film obtained by drying the inkjet ink be −65° C. or lower.

[0025] <Glass transition temperature> The glass transition temperature (Tg) is the temperature at which a molten material changes into a metastable amorphous glass state when cooled. Tg can be measured by a commonly known method using differential scanning calorimetry (DSC) or differential thermal analysis (DTA).

[0026] <Non-crosslinkable urethane resin> Although the mechanism behind this is unclear, it is preferable that the urethane resin does not have crosslinking properties in order to improve durability. Examples of cross-linkable urethane resins include Takelac WS-6021 (self-cross-linkable urethane resin, manufactured by Mitsui Chemicals).

[0027] <Organic solvents> The organic solvent used in the present invention is not particularly limited, and any water-soluble organic solvent can be used, including, for example, polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds. Specific examples of the water-soluble organic solvent include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 1,5-pentanediol, and the like. Polyhydric alcohols such as pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, and petriol, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether. polyhydric alcohol alkyl ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether; nitrogen-containing heterocyclic compounds such as 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, and γ-butyrolactone; amides such as formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, and 3-butoxy-N,N-dimethylpropionamide; amines such as monoethanolamine, diethanolamine, and triethylamine; sulfur-containing compounds such as dimethyl sulfoxide, sulfolane, and thiodiethanol; propylene carbonate; and ethylene carbonate. It is preferable to use an organic solvent having a boiling point of 250° C. or less, since it not only functions as a wetting agent but also provides good drying properties. The content of the organic solvent in the ink is not particularly limited and can be selected appropriately depending on the purpose. From the viewpoint of the drying property and ejection reliability of the ink, however, the content is preferably 10% by mass or more and 60% by mass or less, and more preferably 20% by mass or more and 60% by mass or less.

[0028] <Water> The water content in the ink is not particularly limited and can be selected appropriately depending on the purpose, but from the viewpoint of the drying property and ejection reliability of the ink, it is preferably 10% by mass or more and 90% by mass or less, and more preferably 20% by mass to 60% by mass.

[0029] <Colorant> The coloring material is not particularly limited, and pigments and dyes can be used. The pigment may be an inorganic pigment or an organic pigment. These may be used alone or in combination of two or more. Mixed crystals may also be used. Examples of pigments that can be used include black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, glossy pigments such as gold and silver pigments, and metallic pigments. As inorganic pigments, titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, as well as carbon black produced by known methods such as the contact method, furnace method, and thermal method can be used. In addition, examples of organic pigments that can be used include azo pigments, polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments), dye chelates (e.g., basic dye chelates and acid dye chelates), nitro pigments, nitroso pigments, and aniline black. Of these pigments, those with good affinity for the solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used. Specific examples of pigments for black include carbon blacks (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black, metals such as copper, iron (CI Pigment Black 11), and titanium oxide, and organic pigments such as aniline black (CI Pigment Black 1). In addition, for color, CI Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, CI Pigment Yellow Ranges 5, 13, 16, 17, 36, 43, 51, CI Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48:2, 48:2 (Permanent Red 2B (Ca)), 48:3, 48:4, 49:1, 52:2, 53:1, 57:1 (Brilliant Carmine 6B), 60:1, 63:1, 63:2, 64:1, 81, 83, 88 , 101 (Red Iron), 104, 105, 106, 108 (Cadmium Red), 112, 114, 122 (Quinacridone Magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, CI Pigment Violet 1 (Rhodamine Lake), 3, 5:1, 16, 19, 23, 38; CI Pigment Blue 1, 2, 15 (Phthalocyanine Blue), 15:1, 15:2, 15:3, 15:4 (Phthalocyanine Blue), 16, 17:1, 56, 60, 63; CI Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, etc. The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used, and one type may be used alone, or two or more types may be used in combination. Examples of the dyes include CI Acid Yellow 17, 23, 42, 44, 79, 142, CI Acid Red 52, 80, 82, 249, 254, 289, CI Acid Blue 9, 45, 249, CI Acid Black 1, 2, 24, 94, CI Food Black 1, 2, CI Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, CI Direct Red 1, 4, 9, 80, 81, 225, 227, CI Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, CI Direct Black 19, 38, 51, 71, 154, 168, 171, 195, and CI Reactive Red. 14, 32, 55, 79, 249, and CI Reactive Black 3, 4, and 35.

[0030] The content of the coloring material in the ink is preferably from 0.1% to 15% by mass, more preferably from 1% to 10% by mass, from the viewpoints of improving image density, good fixability, and ejection stability.

[0031] Methods for dispersing a pigment to obtain an ink include a method of introducing a hydrophilic functional group into the pigment to make it a self-dispersing pigment, a method of dispersing the pigment by coating the surface of the pigment with a resin, and a method of dispersing the pigment using a dispersant. As a method for introducing a hydrophilic functional group into a pigment to make it a self-dispersible pigment, for example, a method of adding a functional group such as a sulfone group or a carboxyl group to a pigment (e.g., carbon) to make it dispersible in water can be mentioned. One method for dispersing a pigment by coating its surface with a resin is to encapsulate the pigment in microcapsules to make it dispersible in water. This can be rephrased as a resin-coated pigment. In this case, it is not necessary for all of the pigments blended into the ink to be coated with resin; uncoated or partially coated pigments may be dispersed in the ink, provided that the effects of the present invention are not impaired. Examples of the method for dispersing using a dispersant include a method for dispersing using a known low molecular weight dispersant or a high molecular weight dispersant, such as a surfactant. As the dispersant, for example, anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, etc. can be used depending on the pigment. RT-100 (nonionic surfactant) manufactured by Takemoto Yushi Co., Ltd. and sodium naphthalenesulfonate formalin condensate can also be suitably used as dispersants. The dispersants may be used alone or in combination of two or more.

[0032] <Pigment dispersion> Ink can be obtained by mixing a pigment with water, an organic solvent, or other materials. Alternatively, ink can be produced by mixing a pigment with other materials such as water and a dispersant to form a pigment dispersion, and then mixing the resulting mixture with water, an organic solvent, or other materials. The pigment dispersion is obtained by mixing and dispersing water, a pigment, a pigment dispersant, and optionally other components, and adjusting the particle size. Dispersion is preferably performed using a disperser. Although there are no particular restrictions on the particle size of the pigment in the pigment dispersion, the maximum frequency, calculated as the maximum number, is preferably 20 nm or more and 500 nm or less, and more preferably 20 nm or more and 150 nm or less, in order to improve the dispersion stability of the pigment and image quality such as ejection stability and image density. The particle size of the pigment can be measured using a particle size analyzer (Nanotrac Wave-UT151, manufactured by Microtrac Bell Co., Ltd.). The content of the pigment in the pigment dispersion is not particularly limited and can be appropriately selected depending on the purpose. However, from the viewpoint of obtaining good ejection stability and increasing image density, the content is preferably 0.1% by mass or more and 50% by mass or less, and more preferably 0.1% by mass or more and 30% by mass or less. It is preferable that the pigment dispersion is degassed, if necessary, by filtering coarse particles using a filter, a centrifugal separator, or the like. There are no particular restrictions on the particle size of the solids in the ink and they can be selected appropriately depending on the purpose. However, to improve image quality such as ejection stability and image density, the maximum frequency, calculated as the maximum number, is preferably 20 nm or more and 1000 nm or less, and more preferably 20 nm or more and 150 nm or less. The solids include resin particles and pigment particles. Particle size can be measured using a particle size analyzer (Nanotrac Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).

[0033] <Additives> If necessary, surfactants, antifoaming agents, antiseptics, antifungals, rust inhibitors, pH adjusters, etc. may be added to the ink.

[0034] <Surfactant> As the surfactant, any of silicone surfactants, fluorine surfactants, amphoteric surfactants, nonionic surfactants and anionic surfactants can be used. Silicone surfactants are not particularly limited and can be appropriately selected depending on the purpose.Among them, those that do not decompose even at high pH are preferred, such as side-chain modified polydimethylsiloxane, both-end modified polydimethylsiloxane, one-end modified polydimethylsiloxane, and both-end modified polydimethylsiloxane of side chain, and those having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group are particularly preferred because they exhibit good properties as aqueous surfactants.In addition, polyether-modified silicone surfactants can also be used as the silicone surfactant, and examples thereof include compounds in which a polyalkylene oxide structure is introduced into the Si part side chain of dimethylsiloxane. As fluorosurfactants, for example, perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylic acid compounds, perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in the side chain are particularly preferred due to their low foaming properties. Examples of the perfluoroalkyl sulfonic acid compounds include perfluoroalkyl sulfonic acids and perfluoroalkyl sulfonate salts. Examples of the perfluoroalkyl carboxylic acid compounds include perfluoroalkyl carboxylic acids and perfluoroalkyl carboxylate salts. Examples of the polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in the side chain include sulfate ester salts of polyoxyalkylene ether polymers having perfluoroalkyl ether groups in the side chain, and salts of polyoxyalkylene ether polymers having perfluoroalkyl ether groups in the side chain. Counterions of the salts in these fluorosurfactants include Li, Na, K, NH, NHCHCHOH, NH(CHCHOH), NH(CHCHOH), and the like. Examples of amphoteric surfactants include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine. Examples of nonionic surfactants include polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene alkylamines, polyoxyethylene alkylamides, polyoxyethylene propylene block polymers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and ethylene oxide adducts of acetylene alcohol. Examples of anionic surfactants include polyoxyethylene alkyl ether acetates, dodecylbenzenesulfonates, laurates, and salts of polyoxyethylene alkyl ether sulfates. These may be used alone or in combination of two or more.

[0035] The silicone surfactant is not particularly limited and can be appropriately selected depending on the purpose. Examples include side-chain-modified polydimethylsiloxane, both-end-modified polydimethylsiloxane, one-end-modified polydimethylsiloxane, and both-end-modified side-chain polydimethylsiloxane. Polyether-modified silicone surfactants having a polyoxyethylene group or a polyoxyethylene-polyoxypropylene group as the modifying group are particularly preferred because they exhibit good properties as aqueous surfactants. Such surfactants may be appropriately synthesized or commercially available products, such as those available from BYK-Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Dow Corning Toray Silicone Co., Ltd., Nippon Emulsion Co., Ltd., and Kyoeisha Chemical Co., Ltd. The polyether-modified silicone surfactant is not particularly limited and can be appropriately selected depending on the purpose. For example, it may be a surfactant represented by general formula (S-1) in which a polyalkylene oxide structure is introduced into the Si moiety side chain of dimethylpolysiloxane. [ka] (In the general formula (S-1), m, n, a, and b each independently represent an integer, R represents an alkylene group, and R' represents an alkyl group.) As the polyether-modified silicone surfactant, commercially available products can be used, such as KF-618, KF-642, KF-643 (Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, SS-1906EX (Nihon Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Dow Corning Toray Silicone Co., Ltd.), BYK-33, BYK-387 (BYK-Chemie Co., Ltd.), TSF4440, TSF4452, TSF4453 (Toshiba Silicone Co., Ltd.).

[0036] The fluorine-based surfactant is preferably a compound having 2 to 16 fluorine-substituted carbon atoms, and more preferably a compound having 4 to 16 fluorine-substituted carbon atoms. Examples of fluorine-based surfactants include perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in the side chains. Among these, polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in the side chains are preferred because they have low foaming properties, and fluorine-based surfactants represented by general formula (F-1) and general formula (F-2) are particularly preferred. [ka] In the compound represented by the above general formula (F-1), m is preferably an integer of 0 to 10, and n is preferably an integer of 0 to 40 in order to impart water solubility. General formula (F-2) C n F 2n+1- CH2CH(OH)CH2-O-(CH2CH2O) a -Y In the compound represented by the general formula (F-2), Y is H or C m F 2m+1 where m is an integer from 1 to 6, or CH2CH(OH)CH2-C m F 2m+1 where m is an integer between 4 and 6, or C p H 2p+1 where p is an integer from 1 to 19, n is an integer from 1 to 6, and a is an integer from 4 to 14. As the fluorine-based surfactant, commercially available products may be used, such as Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Fullard FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, and FC-431 (all manufactured by Sumitomo 3M Limited); Megafa F-470, F-1405, F-474 (all manufactured by Dainippon Ink and Chemicals, Inc.); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR, Capstone FS-30, FS-31, FS-3100, FS-34, FS-35 (all manufactured by Chemours); FT-110, FT PF-250, FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Corporation), Polyfox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (manufactured by Omnova), and Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.). Among these, FS-3100, FS-34, FS-300 manufactured by Chemours Corporation, FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW manufactured by Neos Corporation, Polyfox PF-151N manufactured by Omnova, and Unidyne DSN-403N manufactured by Daikin Industries, Ltd. are particularly preferred in terms of achieving good print quality, particularly significant improvements in color development, penetration into paper, wettability, and dye leveling.

[0037] The content of the surfactant in the ink is not particularly limited and can be selected appropriately depending on the purpose. However, from the viewpoint of providing excellent wettability and ejection stability and improving image quality, the content is preferably from 0.001% by mass to 5% by mass, and more preferably from 0.05% by mass to 5% by mass.

[0038] <Antifoaming agent> There are no particular restrictions on the antifoaming agent, and examples thereof include silicone-based antifoaming agents, polyether-based antifoaming agents, fatty acid ester-based antifoaming agents, etc. These may be used alone or in combination of two or more. Among these, silicone-based antifoaming agents are preferred because of their excellent defoaming effect.

[0039] <Antiseptic and mildew-proof agent> There are no particular restrictions on the antiseptic and mildew-proof agent, and examples thereof include 1,2-benzisothiazolin-3-one, etc.

[0040] <Rust inhibitor> There are no particular restrictions on the rust inhibitor, and examples thereof include acid sulfite, sodium thiosulfate, etc.

[0041] <pH adjuster> There are no particular restrictions on the pH adjuster as long as it can adjust the pH to 7 or higher, and examples thereof include amines such as diethanolamine and triethanolamine.

[0042] [[ID=2i]] There are no particular restrictions on the physical properties of the ink, and it can be appropriately selected according to the purpose. For example, it is preferable that the viscosity, surface tension, pH, etc. are in the following ranges. The viscosity of the ink at 25°C is preferably 5 mPa·s or more and 30 mPa·s or less, more preferably 5 mPa·s or more and 25 mPa·s or less, from the viewpoints of improving the printing density and the quality of characters and obtaining good ejection properties. Here, for example, a rotational viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used to measure the viscosity. The measurement conditions are as follows: at 25°C, with a standard cone rotor (1°34’×R24), a sample liquid volume of 1.2 mL, a rotation speed of 50 rpm, and it can be measured in 3 minutes. The surface tension of the ink is preferably 35 mN / m or less, more preferably 32 mN / m or less at 25°C, from the viewpoints of the ink being preferably leveled on the recording medium and shortening the drying time of the ink. The pH of the ink is preferably 7 to 12, more preferably from 8 to 11, from the viewpoint of preventing corrosion of the metal members in contact with the liquid.

[0043] The pretreatment liquid contains a flocculant, an organic solvent, and water, and may also contain surfactants, antifoaming agents, pH adjusters, antiseptic and antifungal agents, rust inhibitors, water-soluble amines, and the like, as required. The organic solvent, surfactant, antifoaming agent, pH adjuster, antiseptic / fungal agent, and antirust agent may be the same as those used in ink, and other materials used in known treatment liquids may also be used. From the viewpoint of the expression of the flocculating function and the liquid contact property, the amount of the flocculant contained in the pretreatment liquid is preferably 5% by mass or more and 20% by mass or less with respect to the total amount of the pretreatment liquid.

[0044] <Flocculant> The flocculant in the present invention means a cationic material for flocculating solid components such as anionic pigments and resins contained in the ink. The flocculant is not particularly limited, and known materials such as metal salts and organic acids can be used.

[0045] <Recordings> The ink recorded matter of the present invention comprises an image formed on a recording medium using the ink of the present invention. Recording can be performed using an inkjet recording apparatus and an inkjet recording method to produce a recorded product.

[0046] <Recording Media> The recording medium used for recording is not particularly limited, but examples of fabric include cotton broadcloth and polyester suede fabric.

[0047] <Recording device and recording method> The ink of the present invention can be suitably used in various recording devices using the ink jet recording method, such as printers, facsimile machines, copying machines, printer / fax / copier combination machines, and three-dimensional modeling devices. In the present invention, the term "recording apparatus" and "recording method" refer to an apparatus capable of ejecting ink or various treatment liquids onto a recording medium, and a method of recording using the apparatus. The term "recording medium" refers to an object onto which ink or various treatment liquids can be attached, even if only temporarily. This recording device can include not only the head portion that ejects ink, but also means related to feeding, transporting, and discharging the recording medium, as well as other devices called pre-processing devices and post-processing devices. The recording apparatus and recording method may have a heating means used in the heating step and a drying means used in the drying step. The heating means and drying means include, for example, means for heating and drying the printed surface and back surface of the recording medium. The heating means and drying means are not particularly limited, but for example, a hot air heater or an infrared heater can be used. Heating and drying can be carried out before, during, or after printing. Furthermore, the recording device and recording method are not limited to those that visualize meaningful images such as letters and figures using ink. For example, they also include those that form patterns such as geometric designs and those that create three-dimensional images. Furthermore, unless otherwise specified, the recording apparatus includes both a serial type apparatus in which the ejection head moves and a line type apparatus in which the ejection head does not move. Furthermore, this recording device includes not only desktop types, but also wide-width recording devices that can print on A0-sized recording media, and continuous feed printers that can use continuous paper wound into a roll as a recording medium, for example. An example of a recording apparatus will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective view of the apparatus. FIG. 2 is a perspective view of a main tank. An image forming apparatus 400, as an example of a recording apparatus, is a serial image forming apparatus. A mechanism unit 420 is provided within an exterior 401 of the image forming apparatus 400. Each ink storage unit 411 of the main tanks 410 (410k, 410c, 410m, 410y) for each color of black (K), cyan (C), magenta (M), and yellow (Y) is formed from a packaging material such as aluminum laminate film. The ink storage unit 411 is housed in a storage container case 414 made of, for example, plastic. As a result, the main tanks 410 are used as ink cartridges for each color. On the other hand, a cartridge holder 404 is provided at the back of the opening when the cover 401c of the device body is opened. A main tank 410 is detachably attached to the cartridge holder 404. This allows each ink outlet 413 of the main tank 410 to communicate with the ejection head 434 for each color via the supply tube 436 for each color, making it possible to eject ink from the ejection head 434 onto a recording medium.

[0048] This recording device can include not only a part that ejects ink, but also devices called pre-processing devices and post-processing devices. As an embodiment of the pre-treatment device and the post-treatment device, a liquid storage section containing a pre-treatment liquid or a post-treatment liquid and a liquid ejection head are added, as in the case of inks such as black (K), cyan (C), magenta (M), and yellow (Y), and the pre-treatment liquid or the post-treatment liquid is ejected by an inkjet recording method. Other embodiments of the pre-treatment device and post-treatment device include those using a method other than the inkjet recording method, such as a blade coating method, a roll coating method, or a spray coating method.

[0049] <Application> The use of the ink of the present invention is not particularly limited and can be appropriately selected depending on the purpose, but it is particularly suitable for use in the textile field where printing is performed on fabrics. [Example]

[0050] EXAMPLES The present invention will be explained in more detail below by showing examples and comparative examples, but the present invention is not limited to these examples. In the examples, "parts" means "parts by mass" and "%" means "% by mass" except for those in the evaluation standards. Hereinafter, "inkjet ink" may be referred to as "ink."

[0051] <Production example of black pigment dispersion> A flask was charged with 11.2 g of styrene, 2.8 g of acrylic acid, 12 g of lauryl methacrylate, 4 g of polyethylene glycol methacrylate, 4 g of styrene macromer, and 0.4 g of mercaptoethanol, and the temperature was raised to 65°C. Next, a mixed solution of 100.8 g of styrene, 25.2 g of acrylic acid, 108 g of lauryl methacrylate, 36 g of polyethylene glycol methacrylate, 60 g of hydroxyethyl methacrylate, 36 g of styrene macromer, 3.6 g of mercaptoethanol, 2.4 g of azobismethylvaleronitrile, and 18 g of methyl ethyl ketone was added dropwise to the flask over 2.5 hours. Then, a mixed solution of 0.8 g of azobismethylvaleronitrile and 18 g of methyl ethyl ketone was added dropwise to the flask over 0.5 hours. After aging at 65°C for 1 hour, 0.8 g of azobismethylvaleronitrile was added, and the mixture was further aged for 1 hour to carry out the reaction. After the reaction was completed, 364 g of methyl ethyl ketone was added to the flask, yielding 800 g of polymer solution A with a solids concentration of 50%. Next, 28 g of polymer solution A, 42 g of carbon black (Black Pearls 1000, manufactured by Cabot Corporation), 13.6 g of 1 mol / L potassium hydroxide aqueous solution, 20 g of methyl ethyl ketone, and 13.6 g of water were thoroughly stirred and then kneaded with a roll mill to obtain a paste. The resulting paste was added to 200 g of pure water and thoroughly stirred, after which the methyl ethyl ketone was removed using an evaporator. The mixture was then pressure-filtered through a polyvinylidene fluoride membrane filter with an average pore size of 5 μm. The water content was adjusted to a solids concentration of 20%, yielding [Black Pigment Dispersion 1] with a solids concentration of 20%.

[0052] <Preparation of Ink 1> The formulation prepared according to the following ink formulation 1 was mixed and stirred, and filtered through a filter with an average pore size of 5 μm (Minisart, manufactured by Sartorius) to prepare [Ink 1]. (Ink formulation 1) Black pigment dispersion 1: 20 parts Hydran WLS-202 (solids concentration 30%, glass transition temperature -68°C): 33 parts SAG503A (Nissin Chemical Industry Co., Ltd., silicone surfactant): 0.1 part Propylene glycol (PG): 20 parts 3-Methyl-1,3-butanediol (MBD): 10 parts Ion exchange water: remaining amount (total: 100 parts)

[0053] <Preparation of Inks 2 to 11> [Inks 2] to [Inks 11] were prepared in the same manner as in the preparation example of [Ink 1], except that the ink formulation was changed to that shown in Table 1.

[0054] <Preparation of pretreatment solution 1> The formulation prepared according to the following pretreatment liquid formulation 1 was mixed and stirred, and filtered through a filter with an average pore size of 5 μm (Minisart, manufactured by Sartorius) to prepare [pretreatment liquid 1]. (Pretreatment solution formulation 1) Calcium nitrate tetrahydrate (Fujifilm Wako Pure Chemical Industries, Ltd.): 10 parts Propylene glycol: 20 parts Ion exchange water: remaining amount (total: 100 parts)

[0055] <Preparation of pretreatment solutions 2 to 6> [Pre-treatment liquid 2] to [Pre-treatment liquid 6] were prepared in the same manner as in the preparation example of [Pre-treatment liquid 1], except that the pre-treatment liquid formulation was changed as shown in Table 2.

[0056] The details of each component in Tables 1, 2 and 3 are as follows: Triethylene glycol (Mitsubishi Chemical Corporation) Glycerin (Sakamoto Pharmaceutical Co., Ltd.) BYK348 (BYK) Acetic acid (Fujifilm Wako Pure Chemical Industries, Ltd.) Malic acid (Fujifilm Wako Pure Chemical Industries, Ltd.) Lactic acid (Tokyo Chemical Industry Co., Ltd.) Citric acid (Kanto Chemical Co., Ltd.) Takelac WS-6021 (Mitsui Chemicals, urethane resin) Hydran WLS-230 (DIC, urethane resin) AP-60LM (DIC, urethane resin) FX-3750 (Nippon Carbide, acrylic resin)

[0057] <Example 1-1> The prints were produced using a DTG printer, Ri100 (manufactured by Ricoh Co., Ltd.). The ink tank mounted on the inkjet printer was filled with [Pretreatment liquid 1] and [Ink 1], and [Pretreatment liquid 1] was applied in an amount of 10 g / m 2 After printing, immediately apply [Ink 1] at a rate of 10 g / m. 2 Printing is then carried out with black ink at a rate of 20 g / m 2 The ink was printed onto cotton broadcloth (Shikisen Co., Ltd.) and polyester tropical fabric (Teijin Co., Ltd.) using a thermostatic oven, and the cotton fabric was dried at 160°C and the polyester fabric at 130°C for 5 minutes to produce printed matter. The resulting prints were evaluated for "color development" and "wet rub fastness" using the evaluation methods described below, and the results are shown in Table 3. In the present invention, the terms "printed matter" and "coating film" are synonymous.

[0058] <Examples 1-2 to 1-8, Comparative Examples 1-1 to 1-3> Printed materials of Examples 1-2 to 1-8 and Comparative Examples 1-1 to 1-3 were produced in the same manner as in Example 1-1, except that [Ink 1] in Example 1-1 was replaced with [Ink 2] to [Ink 11]. The resulting prints were evaluated for "color development" and "wet rubbing fastness." The results are shown in Table 3.

[0059] <Examples 2-1 to 2-13, Comparative Examples 2-1 to 2-4> Printed materials of Examples 2-1 to 2-13 and Comparative Examples 2-1 to 2-4 were produced in the same manner as in Example 1-1, except that the inks and pretreatment liquids in Example 1-1 were changed to the combinations shown in Table 4. The resulting prints were evaluated for "color development" and "wet rubbing fastness." The results are shown in Table 4.

[0060] <Color development> The optical density (OD) of the prints made using the inkjet printer was measured with a colorimeter X-Rite (manufactured by X-Rite Corporation), and the color development was evaluated in terms of black density. The evaluation criteria are as follows, with a grade of △ or higher being a pass. [Evaluation criteria] 〇: Black density is 1.4 or more △: Black density is 1.25 or more and less than 1.4 ×: Black density less than 1.25

[0061] <Wet rubbing fastness> The prints produced using the inkjet printer were subjected to a wet rub fastness test in accordance with JIS L 0849. A score of △ or higher is considered to be acceptable. [Evaluation criteria] 〇: Wet friction fastness is grade 4 or higher △: Wet friction fastness is grade 3 or more but less than grade 4 ×: Wet friction fastness less than grade 3

[0062] [Table 1]

[0063] [Table 2]

[0064] [Table 3]

[0065] [Table 4]

[0066] The present invention includes, for example, the following aspects. (1) An inkjet ink for printing on textiles, Contains water, organic solvents, pigments, and urethane resin. the glass transition temperature of the coating film obtained by drying the inkjet ink is −65° C. or lower; An inkjet ink characterized by: (2) The inkjet ink according to (1) above, wherein the content of the urethane resin contained in 100% by mass of the inkjet ink is 8% by mass or more and 15% by mass or less. (3) The inkjet ink according to (1) or (2) above, wherein the urethane resin is a non-crosslinkable urethane. (4) An ink set comprising a pretreatment liquid and an ink, the pretreatment liquid contains a flocculant, water, and an organic solvent; The ink is the inkjet ink according to any one of (1) to (3) above. An ink set characterized by: (5) The ink set according to (4) above, wherein the aggregating agent is one or more selected from the group consisting of lactic acid, citric acid, and acetic acid. (6) a pretreatment liquid application step of applying a pretreatment liquid to the textile; an ink applying step of applying ink to the textile to which the pretreatment liquid has been applied in a wet-on-wet manner, The pretreatment liquid and the ink are the pretreatment liquid and the inkjet ink of the ink set described in (4) above. A printing method characterized by: (7) a pretreatment liquid applying means for applying a pretreatment liquid to the textile; an ink applying unit that applies ink to the textile to which the pretreatment liquid has been applied in a wet-on-wet manner, The pretreatment liquid and the ink are the pretreatment liquid and the inkjet ink of the ink set described in (4) above. A printing device characterized by: [Explanation of symbols]

[0067] 400 Image forming device 401 Exterior of image forming device 401c Device body cover 404 Cartridge Holder 410 Main Tank 410k, 410c, 410m, 410y Main tanks for black (K), cyan (C), magenta (M), and yellow (Y) 411 Ink storage unit 413 Ink outlet 414 Storage container case 420 Mechanism Department 434 Discharge Head 436 Supply Tube [Prior art documents] [Patent documents]

[0068] [Patent Document 1] International Publication No. 2020 / 090212 [Patent Document 2] Patent No. 6794650

Claims

1. 1. An inkjet ink for printing on textiles, comprising: Contains water, organic solvents, pigments, and urethane resin. the glass transition temperature of the coating film obtained by drying the inkjet ink is −65° C. or lower; An inkjet ink characterized by:

2. 2. The inkjet ink according to claim 1, wherein the content of the urethane resin in 100% by mass of the inkjet ink is 8% by mass or more and 15% by mass or less.

3. 3. The ink-jet ink according to claim 1, wherein the urethane resin is a non-crosslinkable urethane.

4. An ink set comprising a pretreatment liquid and an ink, the pretreatment liquid contains a flocculant, water, and an organic solvent; The ink is the inkjet ink according to claim 1 or 2. An ink set characterized by:

5. The ink set according to claim 4, wherein the aggregating agent is at least one selected from the group consisting of lactic acid, citric acid, and acetic acid.

6. a pretreatment liquid application step of applying a pretreatment liquid to a textile; an ink applying step of applying ink to the textile to which the pretreatment liquid has been applied in a wet-on-wet manner, The pretreatment liquid and the inkjet ink of the ink set according to claim 4 are used as the pretreatment liquid and the ink. A printing method characterized by:

7. a pretreatment liquid applying means for applying a pretreatment liquid to a textile; an ink applying unit that applies ink to the textile to which the pretreatment liquid has been applied in a wet-on-wet manner, The pretreatment liquid and the inkjet ink of the ink set according to claim 4 are used as the pretreatment liquid and the ink. A printing device characterized by:

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