Ink set

Abstract

To provide an ink set which provides a printed matter (fabric) having printed characters and images excellent in scratch resistance, and having good washing fastness and tackiness (no sticking) of a printed surface.SOLUTION: An ink set has a pretreatment liquid and an ink composition, wherein the pretreatment liquid contains an organic acid having a boiling point of 120°C or lower under one atmospheric pressure, and the ink composition contains the following A to E. A: White pigment, B: content of an alkali-soluble resin that is an acrylic copolymer resin having an acid value of 200 mgKOH / g or more and containing a monomer having a carboxyl group and a hydrophobic group-containing monomer as monomer components of 1.0-3.0 mass% in the ink composition, C: water-dispersible resin having a glass transition temperature of -25°C to 10°C, D: silicon-based surface active agent, and E: water.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an ink set comprising a pretreatment liquid and an ink composition.

Background Art

[0002] As described in Patent Document 1, an inkjet recording pretreatment liquid containing composite resin particles in which a polyolefin resin is contained in a polyurethane resin, an organic acid such as malonic acid, a crosslinking agent, and water is known. The image obtained using this pretreatment liquid is said to have no ink bleeding, excellent adhesion, and excellent laminating strength. Considering that such effects are aimed at, it is a pretreatment liquid and an ink composition for printing for lamination. The printing part for such applications is present inside the laminated product and not located in the outermost layer when the printed matter is used. And the invention described in Patent Document 1 does not intend to improve the effects related to the washability and tackiness of the printing part. Patent Document 2 describes that after treating the surface of the object to be printed with an acidic pretreatment liquid, printing is performed with an ink for inkjet recording. It is also described that various acids can be used to make the pretreatment liquid acidic. However, the printed pattern obtained by such printing only has no bleeding in images and the like, and does not intend to improve the effects related to the washability and tackiness of the printing part. Patent Document 3 describes that printing with excellent washing durability is performed on a fabric treated with a pretreatment liquid using a urethane resin-containing white ink composition. However, it is not described up to improving the tackiness as well.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] The problem to be solved by the present invention is to obtain an ink set that can produce a printed matter (fabric) in which printing and images are excellent in rub resistance, and the printed surface has good washing fastness and tackiness (no sticking).

MEANS FOR SOLVING THE PROBLEM

[0005] As a result of intensive research to solve the above problems, the present inventors have found that the above problems can be solved by setting a specific composition, and have completed the present invention. That is, the present invention is as follows. 1. An ink set having a pretreatment liquid and an ink composition, wherein the pretreatment liquid contains an organic acid having a boiling point of 120° C. or lower under 1 atm, and the ink composition contains the following A to E, the ink set. A. White pigment B. An alkali-soluble resin which is an acrylic copolymer resin having an acid value of 200 mgKOH / g or more and containing a monomer having a carboxyl group and a monomer containing a hydrophobic group as monomer components, and the content thereof is 1.0 to 3.0% by mass in the ink composition C. A water-dispersible resin having a glass transition temperature of -25° C. to 10° C D. A silicone-based surfactant E. Water 2. The ink set according to 1, wherein the proportion of the solid content of the water-dispersible resin in the ink composition of C is 10.0 to 30.0% by mass. 3. The ink set according to 1 or 2, which is for inkjet printing. 4. The ink set according to any one of 1 to 3, which is for resist dyeing.

EFFECTS OF THE INVENTION

[0006] According to the ink set of the present invention, prints and images have excellent rub resistance, and a printed matter (fabric) with good washing fastness and tackiness (no sticking) on the printed surface can be obtained.

Embodiments for Carrying Out the Invention

[0007] The ink set of the present invention is an ink set having a pretreatment liquid and an ink composition, which will be described in order below. The ink set may be an ink set for inkjet printing or for resist dyeing.

[0008] The glass transition temperature and weight average molecular weight of the resin in this specification are defined as follows. <Glass Transition Temperature> The glass transition temperature of the resin in the present invention is the theoretical glass transition temperature obtained by the following Wood's equation when the resin is an acrylic copolymer resin. Wood's equation: 1 / Tg = W1 / Tg1 + W2 / Tg2 + W3 / Tg3 + ······ + Wx / Tgx [In the formula, Tg1 to Tgx are the glass transition temperatures of the respective homopolymers of monomers 1, 2, 3 ··· x constituting the resin, W1 to Wx are the polymerization fractions of monomers 1, 2, 3 ··· x respectively, and Tg represents the theoretical glass transition temperature. However, the glass transition temperature in Wood's equation is the absolute temperature.]

[0009] When the resin is other than an acrylic copolymer resin, the glass transition temperature of the resin is the theoretical glass transition temperature obtained by thermal analysis. As a method of thermal analysis, in accordance with JIS K7121 (Method for Measuring the Transition Temperature of Plastics), for example, using a PerkinElmer Pyris1 DSC, the glass transition temperature can be measured under the conditions of a heating rate of 20 ° C / min and a nitrogen gas flow rate of 20 milliliters / min.

[0010] <Weight Average Molecular Weight> The weight average molecular weight of the resin in this specification can be measured by gel permeation chromatography (GPC). As an example, using Water 2690 (Waters) as the GPC device, PLgel, 5 μm, MIXED-D (Polymer Laboratories) as the column, tetrahydrofuran as the eluent, column temperature of 25 °C, flow rate of 1 milliliter / minute, RI detector, sample injection concentration of 10 milligrams / milliliter, and injection volume of 100 microliters, perform chromatography and obtain the weight average molecular weight in terms of polystyrene conversion.

[0011] <Pretreatment liquid> The pretreatment liquid in the present invention contains an organic acid having a boiling point of 120 °C or lower under 1 atm, and may further contain a surfactant as needed. (Organic acid having a boiling point of 120 °C or lower under 1 atm) As the organic acid having a boiling point of 120 °C or lower under 1 atm used in the pretreatment liquid, formic acid (boiling point 100.8 °C under 1 atm) and / or acetic acid (boiling point 118 °C under 1 atm) can be used. Such an organic acid is preferably contained in the pretreatment liquid at 5.0 mass% or more, more preferably 8.0 mass% or more. Also, it is preferably contained at 30.0 mass% or less, more preferably 25.0 mass% or less. If the content of the organic acid is too small, it may take time for the resin in the ink composition printed thereon to be fixed. Also, if it is contained in excess, it may take time for the organic acid to evaporate after printing until the free acid in the printed characters and images disappears.

[0012] (Surfactant) As described above, the pretreatment liquid may or may not contain a surfactant. Preferred surfactants that can be contained are cationic surfactants and nonionic surfactants. If an anionic surfactant or an amphoteric surfactant is contained, it may form a salt with the organic acid having a boiling point of 120 °C or lower under 1 atm. The content of the surfactant is, for example, 0 to 1.0% by mass, preferably 0.01 to 1.0% by mass, more preferably 0.1 to 0.7% by mass with respect to the whole pretreatment liquid.

[0013] As the cationic surfactant, for example, an amidoamine type surfactant or a quaternary ammonium salt surfactant can be adopted. Examples of the amidoamine type surfactant include alkyldimethylaminopropylamide and the like. Examples of the quaternary ammonium salt surfactant include alkyltrimethylammonium chloride, alkyldimethylammonium ethyl sulfate, and alkyldimethylammonium chloride (all from Dai-ichi Kogyo Seiyaku Co., Ltd.) having an alkyl group with 10 to 25 carbon atoms.

[0014] Examples of the nonionic surfactant include one or more selected from silicone-based surfactants, fluorine-based surfactants, and acetylene-based surfactants. Examples of the silicone-based surfactant include BYK-347, BYK-377, BYK-3455 (from BYK Chemie Japan Co., Ltd.) and the like.

[0015] Examples of the fluorine-based surfactant include F-410, F-444, F-553 (all from DIC Corporation), FS-65, FS-34, FS-35, FS-31, FS-30 (all from DuPont) and the like.

[0016] Examples of the acetylene-based surfactant include one or more selected from those commercially available under trade names such as Surfynol 104E, Surfynol 104H, Surfynol 104A, Surfynol 104BC, Surfynol 104DPM, Surfynol 104PA, Surfynol 104PG-50, Surfynol 420, Surfynol 440, Surfynol 465 (Evonik), Dynol 607, Dynol 609, Olfin E1004, Olfin E1010, Olfin E1020, Olfin PD-001, Olfin PD-002W, Olfin PD-004, Olfin PD-005, Olfin EXP.4001, Olfin EXP.4200, Olfin EXP.4123, Olfin EXP.4300 (Nissin Chemical Industry Co., Ltd.).

[0017] (Solvent) In the pretreatment liquid of the present invention, only water or a mixed solvent of water and a water-soluble organic solvent can be adopted as the solvent. Examples of the water-soluble organic solvent include monoalcohols, polyhydric alcohols, lower alkyl ethers of polyhydric alcohols, ketones, ethers, esters, nitrogen-containing compounds, etc. These may be used alone or in combination of two or more. Examples of the monoalcohols include methanol, ethanol, n-propanol, n-butanol, isobutanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, n-nonyl alcohol, n-decanol, or isomers thereof, cyclopentanol, cyclohexanol, etc. Preferably, an alcohol having 1 to 6 carbon atoms in the alkyl group can be used. Examples of the above polyhydric alcohols include ethylene glycol, propylene glycol, 1,3 - butylene glycol, 1,4 - butylene glycol, 1,2 - pentanediol, 1,5 - pentanediol, neopentyl glycol, 1,2 - hexanediol, 1,6 - hexanediol, 1,2 - cyclohexanediol, heptanediol, 1,8 - octanediol, 1,9 - nonanediol, 1,10 - decanediol, glycerin, pentaerythritol, diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, polypropylene glycol, thiodiglycol, etc. which can be used. Examples of the lower alkyl ethers of the above polyhydric alcohols include ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol monopropyl ether, ethylene glycol isopropyl ether, ethylene glycol monobutyl ether, ethylene glycol isobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol - n - propyl ether, propylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, dipropylene glycol mono - n - propyl ether, dipropylene glycol mono - n - butyl ether, etc. which can be used. Specific examples of the above ketones include acetone, methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diisopropyl ketone, cyclopentanone, cyclohexanone, etc. Specific examples of the above ethers include isopropyl ether, n - butyl ether, tetrahydrofuran, tetrahydropyran, 1,4 - dioxane, etc. Examples of the esters include propylene carbonate, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, amyl acetate, ethyl lactate, ethyl butyrate, dibutyl phthalate, dioctyl phthalate, and cyclic esters such as ε-caprolactone and ε-caprolactam. The content of the water-soluble organic solvent is preferably minimized as much as possible and may not be added. However, when added, the content in the pretreatment liquid is preferably 0 to 10.0% by mass, more preferably 0 to 5.0% by mass. When it exceeds 10.0% by mass, there is a possibility of poor drying and reduced blocking resistance.

[0018] (Other components) The pretreatment liquid of the present invention may or may not contain a water-soluble polyvalent metal salt as other components. The water-soluble polyvalent metal salt is a salt of an organic or inorganic acid of a polyvalent metal having a solubility of 1 g / 100 mL or more, preferably 2 g / 100 mL or more, more preferably 20 g / 100 mL or more in 100 mL of water at 20°C. The water-soluble polyvalent metal salt may be a double salt containing a polyvalent metal or a hydrate. Examples of the polyvalent metal include one or more selected from magnesium, calcium, strontium, zinc, copper, iron, and aluminum.

[0019] Examples of the organic acid for constituting the water-soluble polyvalent metal salt include one or more fatty acids represented by RCOOH (wherein R is hydrogen or an organic group having 1 to 30 carbon atoms). Examples of such organic acids include formic acid, acetic acid, propionic acid, octylic acid, lauric acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, stearic acid, 12-hydroxystearic acid, ricinoleic acid, oleic acid, vaccenic acid, linoleic acid, linolenic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, melissic acid, lactic acid, citric acid, gluconic acid, malic acid, tartaric acid, succinic acid, malonic acid, glutaric acid, maleic acid, fumaric acid, glutaconic acid, benzoic acid, ascorbic acid, and the like. Examples of the inorganic acid include one or more selected from nitric acid, sulfuric acid, hydrogen chloride (hydrochloric acid), hydrogen bromide, hydrogen iodide, chloric acid, bromic acid, carbonic acid, and phosphoric acid.

[0020] Examples of the water-soluble polyvalent metal salt which is a polyvalent metal salt of an organic acid include one or more selected from zinc acetate, calcium acetate, strontium acetate, magnesium acetate, zinc formate, calcium formate, strontium formate, copper(II) formate, magnesium formate, calcium benzoate, magnesium benzoate, zinc benzoate, calcium lactate, magnesium lactate, aluminum lactate, iron(II) lactate, copper lactate, calcium ascorbate, magnesium ascorbate, calcium propionate, magnesium propionate, calcium gluconate, magnesium gluconate, zinc gluconate, copper gluconate, zinc citrate, copper citrate, and hydrates thereof.

[0021] In addition, examples of the water-soluble polyvalent metal salt, which is a polyvalent metal salt of an inorganic acid, include zinc chloride, aluminum chloride, calcium chloride, strontium chloride, iron chloride, copper(II) chloride, nickel chloride, magnesium chloride, manganese(II) chloride, zinc bromide, calcium bromide, strontium bromide, iron(II) bromide, copper(II) bromide, magnesium bromide, zinc iodide, calcium iodide, magnesium iodide, aluminum nitrate, calcium nitrate, strontium nitrate, iron(III) nitrate, copper(II) nitrate, magnesium nitrate, zinc sulfate, aluminum sulfate, iron(II) sulfate, iron(III) sulfate, copper sulfate, magnesium sulfate, potassium aluminum sulfate, calcium dihydrogen phosphate, calcium hydrogen carbonate, and one or more selected from hydrates thereof.

[0022] The blending amount of the water-soluble polyvalent metal salt can be appropriately adjusted according to the salt type and the blending purpose, and is not particularly limited. The lower limit of the content of the water-soluble polyvalent metal salt is, for example, 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1% by mass or more in terms of solid content in the pretreatment liquid. The upper limit of the content of the water-soluble polyvalent metal salt is, for example, 20% by mass or less, preferably 15% by mass or less, more preferably 10% by mass or less in terms of solid content in the pretreatment liquid. The content of the water-soluble polyvalent metal salt is, for example, 0.1 to 20% by mass, preferably 0.5 to 15% by mass, more preferably 1 to 10% by mass in terms of solid content in the pretreatment liquid.

[0023] <Ink composition> (A. White pigment) The ink composition in the present invention contains A. white pigment. Examples of the white pigment include titanium oxide, aluminum oxide, etc., and preferably titanium oxide surface-treated with alumina and silica, and titanium oxide surface-treated with alumina, silica and an organic substance. The content of the white pigment in the ink composition is preferably 1.0% by mass or more, more preferably 4.0% by mass or more, and still more preferably 7.0% by mass or more with respect to the total mass of the ink composition. Also, it is preferably 20.0% by mass or less, more preferably 15.0% by mass or less, and still more preferably 13.0% by mass or less. If the content of the white pigment is less than 1.0% by mass, the image quality of the obtained printed matter tends to deteriorate. On the other hand, if it exceeds 20.0% by mass, it tends to have an adverse effect on the viscosity characteristics of the ink composition.

[0024] (Other pigments) In the present invention, pigments other than white may be blended in the ink composition. As such pigments, organic pigments and inorganic pigments that have been conventionally used in ordinary ink compositions can be used without particular limitation. Examples of the organic pigments include, for example, dye lake pigments, azo-based, benzimidazolone-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigo-based, thioindigo-based, perylene-based, perinone-based, diketopyrrolopyrrole-based, isoindolinone-based, nitro-based, nitroso-based, anthraquinone-based, flavanthrone-based, quinophthalone-based, pyranthrone-based, indanthrone-based pigments, etc. Examples of the inorganic pigments include carbon black, titanium oxide, red iron oxide, graphite, iron black, chromium oxide green, aluminum hydroxide, etc. Specific examples of the pigments also include the following. Examples of the yellow pigments include, for example, C.I.PigmentYellow1, 2, 3, 12, 13, 14, 16, 17, 42, 73, 74, 75, 81, 83, 87, 93, 95, 97, 98, 108, 109, 114, 120, 128, 129, 138, 139, 150, 151, 155, 166, 180, 184, 185, 213, etc., and preferably, C.I.PigmentYellow150, 155, 180, 213, etc. Examples of magenta pigments include, for example, C.I.Pigment Red 5, 7, 12, 22, 38, 48:1, 48:2, 48:4, 49:1, 53:1, 57, 57:1, 63:1, 101, 102, 112, 122, 123, 144, 146, 149, 168, 177, 178, 179, 180, 184, 185, 190, 202, 209, 224, 242, 254, 255, 270, C.I.Pigment Violet 19, etc., and preferably, C.I.Pigment Red 122, 202, Pigment Violet 19, etc. Examples of cyan pigments include, for example, C.I.Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 18, 22, 27, 29, 60, etc., and preferably, C.I.Pigment Blue 15:4, etc. Examples of black pigments for use in the black ink composition include, for example, carbon black (C.I.Pigment Black 7), etc. Note that both the above white pigment and other pigments do not have to be colored resin particles.

[0025] (Pigment dispersant) The ink composition in the present invention may contain a pigment dispersant as needed. The pigment dispersant is used to improve the dispersibility of the pigment and the storage stability of the ink composition of the present invention, and those conventionally used can be used without particular limitation, but among them, it is preferable to use a polymer dispersant. Examples of such pigment dispersants include carbodiimide-based dispersants, polyesteramine-based dispersants, fatty acid amine-based dispersants, modified polyacrylate-based dispersants, modified polyurethane-based dispersants, multi-chain polymer non-ionic dispersants, polymer ionic activators, etc. These pigment dispersants can be used alone or in combination of two or more. When the total amount of all pigments used is 100 parts by mass, it is preferably contained in an amount of 1 to 200 parts by mass. When the content of the pigment dispersant is less than 1 part by mass, the pigment dispersion and the storage stability of the ink composition of the present invention may decrease. On the other hand, although it can be contained in an amount exceeding 200 parts by mass, there may be no difference in the effect. A more preferable lower limit of the content of the pigment dispersant is 5 parts by mass, and a more preferable upper limit is 60 parts by mass.

[0026] (B. An alkali-soluble resin which is an acrylic copolymer resin having an acid value of 200 mgKOH / g or more and containing a monomer having a carboxyl group and a hydrophobic group-containing monomer as monomer components, and the content thereof is 1.0 to 3.0% by mass in the ink composition) The alkali-soluble resin having an acid value of 200 mgKOH / g or more contains a monomer having a carboxyl group and a hydrophobic group-containing monomer as monomer components. And this alkali-soluble resin is contained in the ink composition in an amount of 1.0% by mass or more. And 1.3% by mass or more is preferable, and 1.5% by mass or more is more preferable. Also, it is contained in an amount of 3.0% by mass or less. And 2.6% by mass or less is preferable, and 2.3% by mass or less is more preferable.

[0027] From the viewpoint of enhancing the dispersibility of the pigment, the content of the alkali-soluble resin is preferably 5.0 parts by mass or more, more preferably 15.0 parts by mass or more, based on 100 parts by mass of the pigment. From the viewpoint of reducing the viscosity of the ink composition, the content of the alkali-soluble resin is preferably 100.0 parts by mass or less, more preferably 70.0 parts by mass or less, and further preferably 40.0 parts by mass or less, based on 100 parts by mass of the pigment.

[0028] As the acrylic copolymer resin, for example, a mixture of a monomer having a carboxyl group and other copolymerizable monomers can be polymerized in a solvent in the presence of a usual radical generator (for example, benzoyl peroxide, tertiary butyl peroxybenzoate, azobisisobutyronitrile, etc.) to obtain a product that can be used. In addition to the monomer having a carboxyl group, a monomer having at least one anionic group selected from the group consisting of a sulfonic acid group and a phosphonic acid group may be used in combination. However, it is particularly preferable to use only the monomer having a carboxyl group as the anionic group-containing monomer.

[0029] Examples of the monomer having a carboxyl group include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, 2-carboxyethyl (meth)acrylate, 2-carboxypropyl (meth)acrylate, maleic anhydride, fumaric anhydride, maleic acid half ester, and the like. Examples of the monomer having a sulfonic acid group include sulfonatoethyl methacrylate and the like. Examples of the monomer having a phosphonic acid group include phosphonatoethyl methacrylate and the like.

[0030] As another monomer copolymerizable with the monomer having a carboxyl group, it is a monomer containing a hydrophobic group-containing monomer from the viewpoint of improving the adsorptivity with a pigment. Examples of the hydrophobic group-containing monomer include, as a monomer having a long-chain alkyl group, alkyl esters of radical polymerizable unsaturated carboxylic acids such as (meth)acrylic acid having 8 or more carbon atoms (for example, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, 2-hydroxystearyl (meth)acrylate, etc.), alkyl vinyl ethers having 8 or more carbon atoms (for example, dodecyl vinyl ether, etc.), vinyl esters of fatty acids having 8 or more carbon atoms (for example, vinyl 2-ethylhexanoate, vinyl laurate, vinyl stearate, etc.); as a monomer having an alicyclic hydrocarbon group, cyclohexyl (meth)acrylate, etc.; as a monomer having an aromatic hydrocarbon group, styrene-based monomers such as benzyl (meth)acrylate, styrene, α-methylstyrene, vinyltoluene, etc. The hydrophobic group-containing monomer can be used alone or in combination of two or more.

[0031] As the other monomer copolymerizable with the monomer having a carboxyl group, from the viewpoint of suppressing aggregation of the alkali-soluble resin in an aqueous medium, a hydrophilic group-containing monomer can be included.

[0032] Examples of the hydrophilic group-containing monomer include, as a monomer having a (poly)oxyalkylene chain, an esterified product of a radical polymerizable unsaturated carboxylic acid such as (meth)acrylic acid and a mono-terminal alkyl-blocked (poly)alkylene glycol such as methoxypolyethylene glycol, methoxypolyethylene polypropylene glycol, ethoxypolyethylene glycol, ethoxypolyethylene polypropylene glycol, propoxypolyethylene glycol, propoxypolyethylene polypropylene glycol, and the like; an ethylene oxide adduct and / or a propylene oxide adduct to a radical polymerizable unsaturated carboxylic acid such as (meth)acrylic acid; Examples of the basic group-containing monomer include vinylpyrrolidones such as 1-vinyl-2-pyrrolidone and 1-vinyl-3-pyrrolidone; vinylpyridines such as 2-vinylpyridine, 4-vinylpyridine, 5-methyl-2-vinylpyridine, and 5-ethyl-2-vinylpyridine; vinylimidazoles such as 1-vinylimidazole and 1-vinyl-2-methylimidazole; vinylpiperidines such as 3-vinylpiperidine and N-methyl-3-vinylpiperidine; nitrogen-containing derivatives of (meth)acrylic acid such as dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, (meth)acrylic acid tert-butylaminoethyl, (meth)acrylamide, N-methylol (meth)acrylamide, N-butoxymethyl (meth)acrylamide, N-methoxy (meth)acrylamide, N-ethoxy (meth)acrylamide, N-dimethylacrylamide, and N-propylacrylamide; Examples of the monomer having a hydroxyl group include hydroxyalkyl esters of (meth)acrylic acid such as hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate; Examples of the monomer having an epoxy group include glycidyl (meth)acrylate. The hydrophilic group-containing monomer can be used alone or in combination of two or more.

[0033] Examples of the copolymerizable other monomers other than the hydrophobic group-containing monomer and the hydrophilic group-containing monomer include alkyl esters of (meth)acrylic acid having less than 8 carbon atoms such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, and cyclohexyl (meth)acrylate. The copolymerizable other monomers other than the hydrophobic group-containing monomer and the hydrophilic group-containing monomer can be used alone or in combination of two or more.

[0034] The alkali-soluble resin preferably has a mass ratio of monomers of styrene / alkyl ester of radically polymerizable unsaturated carboxylic acid having 8 or more carbon atoms / (meth)acrylic acid = 35 to 55 / 25 to 35 / 15 to 35, more preferably styrene / lauryl acrylate / acrylic acid = 35 to 55 / 25 to 35 / 15 to 35. Also preferably, (meth)acrylate of alicyclic hydrocarbon having 8 or less carbon atoms / acrylic acid / methacrylic acid = 50 to 70 / 13 to 25 / 15 to 25, more preferably cyclohexyl acrylate / acrylic acid / methacrylic acid = 50 to 70 / 13 to 25 / 15 to 25. From the viewpoint of appropriately crosslinking the alkali-soluble resin to suppress aggregation of pigments, a crosslinking agent having two or more functional groups may or may not be used.

[0035] The crosslinking agent having two or more functional groups may have two or more reactive functional groups in the molecule in order to react with the functional groups of the alkali-soluble resin. Examples of the reactive functional group include an epoxy group, a hydroxyl group, an isocyanate group, an amino group, and an aziridine group. Furthermore, a crosslinking agent that is dispersed, emulsified, or dissolved in water or can be dispersed, emulsified, and / or dissolved in water is particularly preferred. The crosslinking agent having two or more functional groups can be used alone or in combination of two or more.

[0036] The acid value of the alkali-soluble resin is 200 mgKOH / g or more, more preferably 210 mgKOH / g or more, and even more preferably 220 mgKOH / g or more, from the viewpoint of enhancing the reactivity with the organic acid contained in the pretreatment liquid. Also, the acid value of the alkali-soluble resin is preferably 300 mgKOH / g or less, more preferably 250 mgKOH / g or less, and even more preferably 240 mgKOH / g or less, from the viewpoint of improving the water resistance of the printed matter. Note that the acid value is the theoretical acid value obtained arithmetically by calculating the number of mg of potassium hydroxide theoretically required to neutralize 1 g of the alkali-soluble resin based on the composition of the monomers used to synthesize the alkali-soluble resin.

[0037] The glass transition temperature of the alkali-soluble resin is preferably 0°C or higher, more preferably 20°C or higher, and even more preferably 40°C or higher, from the viewpoint of improving the blocking resistance of the printed matter. The glass transition temperature of the alkali-soluble resin is preferably 100°C or lower, more preferably 80°C or lower, and even more preferably 60°C or lower, from the viewpoint of improving the bend resistance of the printed matter.

[0038] The weight average molecular weight of the alkali-soluble resin is 5,000 or more, more preferably 8,000 or more, and even more preferably 9,000 or more, from the viewpoint of improving the water resistance of the printed matter. The weight average molecular weight of the alkali-soluble resin is 50,000 or less, preferably 40,000 or less, and more preferably 30,000 or less, from the viewpoint of enhancing the solubility in the aqueous medium. Also, this alkali-soluble resin may be neutralized with a basic compound. Examples of the basic compound include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and organic basic compounds such as alkylamines and alkanolamines.

[0039] (C. Water-dispersible resin with a glass transition temperature of -25°C to 10°C) As the water-dispersible resin, one or more selected from acrylic resin emulsions, styrene-acrylic resin emulsions, polyurethane resin emulsions, and polyolefin resin emulsions can be employed. Among them, it is preferable to use only acrylic resin emulsions and / or styrene-acrylic resin emulsions. The glass transition temperature of this water-dispersible resin is from -25°C to 10°C, and among them, those of -20°C or higher, -15°C or higher, -10°C or higher, -5°C or higher, 0°C or higher, and 3°C or higher are preferably in this order.

[0040] From the viewpoint of improving the printing image quality and abrasion resistance, the proportion of the solid content of the water-dispersible resin in the ink composition in the present invention is preferably 10.0% by mass or more, more preferably 13.0% by mass or more, and from the viewpoint of improving the printing image quality, it is preferably 30.0% by mass or less, more preferably 25.0% by mass or less. Also, from the viewpoint of improving the printing image quality and abrasion resistance, the proportion of the solid content of the water-dispersible resin with respect to the total amount of the resin and the pigment in the ink composition in the present invention is preferably 30.0% by mass or more, more preferably 40.0% by mass or more, still more preferably 50.0% by mass or more, and most preferably 60.0% by mass or more. And from the viewpoint of improving the printing image quality, it is preferably 93.0% by mass or less, more preferably 90.0% by mass or less. Also, from the viewpoint of enhancing the acid resistance, the acid value of the water-dispersible resin is preferably 25.0 mgKOH / g or less, more preferably 20.0 mgKOH / g or less, still more preferably 15.0 mgKOH / g or less, most preferably 13.0 mgKOH / g or less, and it may be 0 mgKOH / g, and preferably 5.0 mgKOH / g or more. The acid value is the theoretical acid value obtained arithmetically by calculating the number of milligrams of potassium hydroxide theoretically required to neutralize 1 g of the alkali-soluble resin based on the composition of the monomers used for synthesizing the alkali-soluble resin. The acrylic resin emulsion is a polymer obtained by mixing one or more of the following monomers. For example, (meth)acrylic acid esters with alcohols having an alkyl group with 1 to 18 carbon atoms, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, methoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, glycidyl (meth)acrylate, allyl (meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, etc. can be mentioned. Note that (meth)acrylate is a general term for acrylate and methacrylate. In addition to the above, the following ethylenically unsaturated monomers may be used in combination. For example, acrylonitrile, vinyl acetate, vinyl propionate, styrene, acrylic acid, methacrylic acid, (meth)acrylamide, N-methylol (meth)acrylamide, N-methoxymethyl (meth)acrylamide, etc. can be mentioned. Among them, in order to more effectively exhibit the effects of the present invention, a copolymer formed by copolymerizing three monomers of (meth)acrylic acid, alkyl methacrylate, and alkyl acrylate is preferable. Furthermore, the composition of each monomer in this copolymer is preferably 0.5 to 10.0 parts by mass of (meth)acrylic acid, 15.0 to 60.0 parts by mass of alkyl methacrylate, and 30.0 to 80.0 parts by mass of alkyl acrylate.

[0041] Styrene acrylic resin emulsion is an emulsion in which styrene acrylic resin is dispersed in water, and it can be produced by emulsion polymerization, dispersion polymerization, suspension polymerization, grinding, or solution / bulk polymerization, followed by post-emulsification. Detailed information on this method and stabilizer is described in "Emulsion Polymerization and Emulsion Polymer" (P.A. Lovell, M.S. El-Aasser, John Wiley & Sons Ltd., England, 1977, incorporated herein by reference). Examples of commercially available styrene-acrylic resin emulsions include M6963 (Japan Coating Resin Co., Ltd.), J-450, J-734, J-7600, J-352, J-390, J-7100, J-741, J-74J, J-511, J-840, J-775, HRC-1645, HPD-71, PDX-6102B, JDX-5050 (styrene-acrylic resin emulsion, BASF), UC-3900 (styrene-acrylic resin emulsion, Toagosei Co., Ltd.), and the like.

[0042] The polyurethane resin emulsion is an emulsion in which a polyurethane resin is dispersed in water, and any of anionic, cationic, and nonionic types can be used, but anionic and nonionic types are preferred. Examples of the polyurethane resin include polyether-based polyurethane resins, polyester-based polyurethane resins, polyester-polyether-based polyurethane resins, polycarbonate-based polyurethane resins, and the like. The polyurethane resin emulsion can be used alone or in combination of two or more.

[0043] Examples of commercially available polyurethane resin emulsions include "Superflex 210" (Daiichi Kogyo Seiyaku Co., Ltd., anionic polyester-based polyurethane resin), "Superflex 130" (Daiichi Kogyo Seiyaku Co., Ltd., anionic polyether-based polyurethane resin), "Superflex 500M" (Daiichi Kogyo Seiyaku Co., Ltd., nonionic polyester-based polyurethane resin), "Superflex 460" (Daiichi Kogyo Seiyaku Co., Ltd., anionic polycarbonate-based polyurethane resin), "Impranil DLP" (Sumika Covestro Polyurethanes Co., Ltd., anionic polyester-based polyurethane resin), "Baybond PU407" (Sumika Covestro Polyurethanes Co., Ltd., anionic / nonionic polyester-based polyurethane resin), Superflex 420NS (Daiichi Kogyo Seiyaku Co., Ltd., anionic polycarbonate-based polyurethane resin), Takelac W series (polyurethane resin emulsion, Mitsui Chemicals, Inc.), R967, acid value 19 mgKOH / g, (trade name "NeoRez R-967, polyether polyurethane emulsion (solid content concentration 40% by mass), DSM Neoresins Co., Ltd.), and the like.

[0044] The polyolefin resin emulsion is an emulsion in which a polyolefin resin is dispersed in water. Examples of the polyolefin resin include a polyethylene resin, a polypropylene resin, a polybutylene resin, and a polyolefin resin obtained by copolymerizing two or more of ethylene, propylene, and butylene. Further, the polyolefin resin may be a modified polyolefin resin in which an amino group, a carboxyl group, a hydroxyl group, an acryloyl group, or another polymer chain is introduced into the polyolefin chain; an oxidized polyolefin resin in which a part of the polyolefin chain is oxidized; a halogenated polyolefin resin in which a part is treated with a halogen, and the like. The polyolefin resin emulsion can be used alone or in combination of two or more.

[0045] Examples of commercially available polyolefin resin emulsions include "Chemiparle S100" (Mitsui Chemicals, polyethylene resin emulsion), "Chemiparle XEP800H" (Mitsui Chemicals, polypropylene resin emulsion), "Arrowbase TC-4010" (Unitika, polypropylene resin emulsion), and the like.

[0046] The resin emulsion may contain, within a range that does not impair the effects of the present invention, known resin emulsions (other resin emulsions) used in ink compositions, such as AP4710 (acrylic-silicone resin emulsion, Showa High Polymer Co., Ltd.), other than the acrylic resin emulsion, the styrene-acrylic resin emulsion, the polyurethane resin emulsion, and the polyolefin resin emulsion. Examples of such other resin emulsions include polyvinyl acetate resin emulsions and polyvinyl chloride resin emulsions.

[0047] In the resin emulsion, from the viewpoint of improving the coating film resistance such as scratch resistance, 70% by mass or more of the styrene-acrylic resin emulsion and / or the polyurethane resin emulsion is preferable, 80% by mass or more is more preferable, 90% by mass or more is further preferable, and 95% by mass or more is most preferable.

[0048] (D. Silicon-based surfactant) The ink composition of the present invention can contain a D. silicon-based surfactant in order to optimize the printing and printing-dyeing processes. Further, when making the ink composition for inkjet, depending on the inkjet head to be used, it is preferable to contain a D. silicon-based surfactant conventionally used in ink compositions as a surfactant in order to improve the ejection stability. Specific examples of the silicone-based surfactant include polyether-modified hydroxyl group-containing polydimethylsiloxane such as BYK-377 (BYK Chemie), polyether-modified polydimethylsiloxane such as BYK-302, BYK-306, BYK-331, BYK-333, BYK-349, and BYK-378 (BYK Chemie), polyether ester-modified polydimethylsiloxane such as BYK-307 and BYK-375 (BYK Chemie), polyester-modified polydimethylsiloxane such as BYK-310 and BYK-313 (BYK Chemie), polyester-modified hydroxyl group-containing polydimethylsiloxane such as BYK-370 (BYK Chemie), polyester-modified methylalkylpolysiloxane, macromer-modified acrylate of silicone and polyether such as BYK-3566 (BYK Chemie), and the like. These can be used alone or in combination of two or more kinds. The content of the surfactant in the ink composition of the present invention is preferably 0.005 to 1.0% by mass. If it is less than 0.005% by mass, the surface tension of the ink composition of the present invention becomes high, and the ejection stability from the inkjet head decreases. On the other hand, if it exceeds 1.0% by mass, the number of bubbles in the ink composition increases and the ejection stability decreases.

[0049] (E. Water) The ink composition of the present invention uses water as a solvent. Or, a mixed solvent of a water-soluble organic solvent may be further contained in water. Examples of this water-soluble organic solvent include monoalcohols, polyhydric alcohols, lower alkyl ethers of polyhydric alcohols, ketones, ethers, esters, nitrogen-containing compounds, and the like. These may be used alone or in combination of two or more kinds. As these water-soluble organic solvents, those that can be used in the above pretreatment liquid can be used in a similar content.

[0050] (Additive) In the ink composition of the present invention, various additives can be added as needed to exhibit various functionalities. Specifically, other surfactants, surface modifiers, light stabilizers, surface treatment agents, antioxidants, anti-aging agents, crosslinking accelerators, polymerization inhibitors, plasticizers, preservatives, pH adjusters, defoamers, humectants, etc. can be mentioned. Further, a resin that functions as a vehicle but is not curable may or may not be blended. Also, a solvent may or may not be contained.

[0051] (Basic compound) From the viewpoint of dissolving the alkali-soluble resin, the ink composition of the present invention may contain a basic compound. Examples of the basic compound include inorganic basic compounds such as sodium hydroxide and potassium hydroxide; organic basic compounds such as ammonia, methylamine, ethylamine, monoethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, N,N-dibutylethanolamine, diethanolamine, N-methyldiethanolamine, triethanolamine, morpholine, N-methylmorpholine, and N-ethylmorpholine. The basic compound can be used alone or in combination of two or more.

[0052] The proportion of the basic compound in the ink composition of the present invention may be an amount that dissolves the alkali-soluble resin in the medium. Usually, from the viewpoint of enhancing the dispersion stability of the alkali-soluble resin, it is preferably 0.05% by mass or more, more preferably 0.1% by mass or more. And from the viewpoint of enhancing the water resistance of the printed matter, it is preferably 1% by mass or less, more preferably 0.5% by mass or less.

[0053] In the ink composition of the present invention, additives such as known resins, pigment dispersants, antifungal agents, rust inhibitors, thickeners, antioxidants, ultraviolet absorbers, preservation improvers, defoamers, pH adjusters, etc. can be further added according to the purpose.

[0054] <Method for preparing the pretreatment liquid> The pretreatment liquid in the present invention can be prepared by adding predetermined amounts of an organic acid and, if necessary, a surfactant or the like to water in any order.

[0055] <Method for preparing ink composition> The method for preparing (manufacturing) the ink composition in the present invention is not particularly limited, and the above components may be added in order or simultaneously and mixed. For example, the methods (1) and (2) below can be adopted. (1) An aqueous resin varnish in which an alkali-soluble resin is dissolved in water in the presence of the basic compound, a pigment, and, if necessary, a pigment dispersant or the like are mixed, and then a pigment dispersion liquid (ink base) is prepared using various dispersing machines such as a ball mill, an attritor, a roll mill, a sand mill, an agitator mill, etc., and then the remaining materials are added to prepare an ink composition. (2) After dispersing the pigment by the above method, a resin-coated pigment in which an alkali-soluble resin is deposited on the pigment surface is obtained by an acid precipitation method or known ion exchange means described in Published Patent WO2005 / 116147, etc. Then, the obtained resin-coated pigment is neutralized with a basic compound, redispersed in water using various dispersing machines (such as a high-speed stirring device), and then the remaining materials are added to prepare an ink composition. The ink composition in the present invention has an initial viscosity after production in the range of 2.0 to 15.0 mPa·s, preferably 3.0 to 12.0 mPa·s. The viscosity can be measured, for example, with an E-type viscometer (trade name "RE100L-type viscometer", manufactured by Toki Sangyo Co., Ltd.).

[0056] <Printing method using the ink set of the present invention> The printing method using the ink set of the present invention consists of two steps: a step of applying a pretreatment liquid to the surface of a printing substrate such as printing paper or a resin film, and a printing step of performing printing with the ink composition. The step of applying the pretreatment liquid may be performed by inkjet printing or by other well-known methods. Regarding these two steps, the step of performing printing with the ink composition may be performed in a wet-on-wet manner where the applied pretreatment liquid is not dried, or may be performed in a dry-on-wet manner after drying the applied pretreatment liquid.

Example

[0057] <Pretreatment liquid> Pretreatment liquid 1 (prepared by stirring and mixing 20 parts by mass of acetic acid, 0.2 parts by mass of Surfynol 440 (an acetylene diol-based surfactant, HLB 8, manufactured by Evonik Industries AG), and purified water to make 100 parts by mass) Pretreatment liquid 2 (prepared by using 10 parts by mass of acetic acid in pretreatment liquid 1) Pretreatment liquid 3 (prepared by substituting acetic acid in pretreatment liquid 1 with lactic acid (an organic acid having a boiling point exceeding 120°C under 1 atm))

[0058] <Ink composition> (Pigment) JR-809 (trade name “JR-809”, titanium oxide treated with silica and alumina, average particle diameter 0.23 μm, DBP oil absorption 24 ml / 100 g, manufactured by Teika Co., Ltd.) PF-690 (trade name “PF-690”, titanium oxide treated with silica, alumina, and an organic substance, average particle diameter 0.21 μm, DBP oil absorption 16 ml / 100 g, manufactured by Ishihara Sangyo Co., Ltd.)

[0059] (Alkali-soluble resin) Alkali-soluble resin 1 (a copolymer of cyclohexyl acrylate / acrylic acid / methacrylic acid = 65 / 16 / 19 with a weight average molecular weight of 9,500 and an acid value of 235 mgKOH / g) Alkali-soluble resin 2 (a copolymer of styrene / lauryl acrylate / acrylic acid = 40 / 30 / 30 with a weight average molecular weight of 30,000 and an acid value of 220 mgKOH / g)

[0060] (Alkali-soluble resin varnish) 25 parts by mass of the above alkali-soluble resin 1, sodium hydroxide with a neutralization equivalent of 100%, and purified water were mixed to make 100 parts by mass, and heated and stirred at 90 °C for dissolution to obtain an alkali-soluble resin varnish 1. Similarly, 25 parts by mass of the above alkali-soluble resin 2, sodium hydroxide with a mass that gives a neutralization equivalent of 100%, and purified water were mixed to make 100 parts by mass, and heated and stirred at 90 °C for dissolution to obtain alkali-soluble resin varnishes 2, respectively.

[0061] (Aqueous white ink base) After stirring and mixing 50 parts by mass of JR-809, 40 parts by mass of the alkali-soluble resin varnish 1, and 10 parts by mass of purified water, kneading was performed with a wet circulation mill to prepare an aqueous white ink base 1. Similarly, after stirring and mixing 50 parts by mass of PF-690, 40 parts by mass of the alkali-soluble resin varnish 2, and 10 parts by mass of purified water, kneading was performed with a wet circulation mill to prepare an aqueous white ink base 2.

[0062] (Water-dispersible resin) (Method for producing water-dispersible resin 1 (Tg = 0 °C)) To a mixture of monomers consisting of 1.5 parts by mass of acrylic acid, 46.1 parts by mass of methyl methacrylate, and 52.4 parts by mass of butyl acrylate, 3 parts by mass of Aqualon HS-10 (Dai-ichi Kogyo Seiyaku Co., Ltd.) as a surfactant was added, and further an aqueous solution prepared by dissolving 0.3 parts by mass of potassium persulfate in 46 parts by mass of distilled water was added and emulsified in advance with a stirrer. 20 parts by mass of distilled water was put into a polymerization vessel equipped with a stirrer, a condenser, a thermometer, and a nitrogen inlet tube, purged with nitrogen, and heated to 80 °C. Then, the emulsion of the above monomers was dropped over 3 hours, and further reacted for 2 hours to complete the polymerization. However, a small amount of potassium persulfate was added in the latter stage of polymerization to consume the remaining monomers. Sodium hydroxide was added to the obtained emulsion to adjust the pH to 7.5, and then distilled water was added so that the solid content concentration became 50% by mass to obtain water-dispersible resin 1 (glass transition temperature 0 °C, solid content 50% by mass).

[0063] (Method for producing water-dispersible resin 2 (Tg = 5 °C)) In the production of the above acrylic resin emulsion 1, the monomer composition was changed to a monomer consisting of 1.5 parts by mass of acrylic acid, 49.5 parts by mass of methyl methacrylate, and 49.0 parts by mass of butyl acrylate, and it was produced by the same method.

[0064] (Method for producing water-dispersible resin 3 (Tg = -20 °C)) In the production of the above acrylic resin emulsion 1, the monomer composition was changed to a monomer consisting of 1.5 parts by mass of acrylic acid, 31.1 parts by mass of methyl methacrylate, and 67.4 parts by mass of butyl acrylate, and it was produced by the same method.

[0065] (Method for producing water-dispersible resin 4 (Tg = -30 °C)) In the production of the above acrylic resin emulsion 1, the monomer composition was changed to a monomer consisting of 1.5 parts by mass of acrylic acid, 22.8 parts by mass of methyl methacrylate, and 75.7 parts by mass of butyl acrylate, and it was produced by the same method.

[0066] M6963 (trade name "M6963", styrene-acrylic emulsion (Tg = -26 °C, solid content concentration 45% by mass), acid value less than 10 mg KOH / g, Japan Coating Resin Co., Ltd.)

[0067] (Silicone surfactant) BYK-377 (polyether-modified hydroxyl group-containing polydimethylsiloxane, BYK Chemie GmbH) (Solvent) Glycerin Propylene glycol (Additive) E1010 (trade name "Olfin E-1010", acetylene diol-based surfactant, HLB 13, Nisshin Chemical Industry Co., Ltd.)

[0068] <Production of ink composition> As shown in Table 1, each component was stirred and mixed to obtain the ink compositions of each example and comparative example.

[0069]

Table 1

[0070] <Production of Nara-dyed Fabric> The pretreatment liquids of the examples and comparative examples were impregnated at 10 g per A4-sized area of 100% cotton black fabric, and then heat-dried to obtain a printing medium. For the said printing medium, a solid image was printed using an evaluation printer equipped with a SPECTRA head and the ink compositions of the examples and comparative examples to obtain a Nara-dyed fabric.

[0071] <Evaluation Method> (Washing Fastness) The Nara-dyed fabrics of Examples 1 to 5 and Comparative Examples 1 to 4 were subjected to normal washing (washing conditions: washing → dehydration → drying in a normal mode, water temperature during washing about 20°C) 5 times in a household washing machine, and the lightness of each Nara-dyed fabric before and after washing was measured using a color difference meter (product name "DR-321", Konica Minolta), and the change rate from the initial value of the lightness (L*) before washing was measured and evaluated according to the following criteria. ◎: Those in which the image density remains at 90% or more of the initial value after washing ○: Those in which the image density is 80% or more and less than 90% of the initial value after washing △: Those in which the image density is 70% or more and less than 80% of the initial value after washing ×: Those in which the image density is less than 70% of the initial value after washing

[0072] (Tackiness) The white solid part of the Nara-dyed fabric was evaluated by finger touch according to the following criteria. ○: The coating film does not stick to the finger. △: The coating film sticks to the finger but peels off immediately. ×: The coating film sticks to the finger.

[0073] According to Examples 1 to 5 which are examples along the present invention, images and the like excellent in washing fastness and tackiness can be formed. However, according to Comparative Example 1 containing M6963 as the water-dispersible resin and Comparative Example 2 containing a water-dispersible resin having a glass transition temperature of -30°C, the tackiness of the printed matter was not good. Further, according to Comparative Example 3 not containing a silicone-based surfactant, the washing fastness was insufficient and the tackiness was also not good. Further, according to Comparative Example 4 using an organic acid having a boiling point exceeding 120°C under 1 atm, the washing fastness was insufficient.

Claims

1. An ink set having a pretreatment liquid and an ink composition, wherein the pretreatment liquid contains, as an organic acid, only an organic acid having a boiling point of 120° C. or lower under 1 atm, and the ink composition contains the following A to E: The ink set. A. White pigment B. The content of an alkali-soluble resin, which is an acrylic copolymer resin containing, as monomer components, a monomer having an acid value of 200 mgKOH / g or higher and having a carboxyl group and a hydrophobic group-containing monomer, is 1.0 to 3.0% by mass in the ink composition C. A water-dispersible resin having a glass transition temperature of -25° C. to 10° C D. A silicone-based surfactant E. Water

2. The ink set according to claim 1, wherein C. the proportion of the solid content of the water-dispersible resin in the ink composition is 10.0 to 30.0% by mass.

3. The ink set according to claim 1 or 2, which is for inkjet printing.

4. The ink set according to any one of claims 1 to 3, which is for printing by transfer printing.

Images