White pigment ink composition for inkjet printing, and ink set

Abstract

To provide a white pigment ink which has high whiteness, is hardly precipitated and is excellent in dispersion stability, and an ink set which enables formation of a color image excellent in texture and having high friction fastness and low stickiness when a color ink is applied onto a base formed from the white pigment ink.SOLUTION: A white pigment ink composition for inkjet printing contains a white pigment, a polymeric dispersant, an urethane resin, a water-soluble organic solvent, and water, wherein a volume average particle diameter (D50) of the white pigment is 200 to 270 nm, and the water-soluble organic solvent contains glycerol, and polyhydric alcohol having a boiling point of 215°C or lower.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an ink set including a white pigment ink composition for ink-jet textile printing and color inks. [Background technology]

[0002] Traditionally, hand-drawing and screen printing have been the mainstream methods for textile printing, but recently, textile printing using inkjet printers (inkjet printing) has become increasingly popular. Inkjet printing methods are more suitable for printing a wide variety of items in small quantities than analog printing methods such as screen printing and gravure printing, and there is a demand for an expanded range of fabric applications for inkjet printing methods. Along with this expansion of the range of applications, there is a demand for further improvements in density and fastness (e.g., rubbing fastness, washing fastness, lightfastness, etc.) in garment printing and home textile printing for various fabrics (e.g., cotton, polyester, nylon, or blends containing two or more types of fibers) and various types of fabrics (e.g., knit, sheeting, broadcloth, oxford, chambray, mesh, etc.).

[0003] Water-soluble dyes are used as colorants in inkjet printing. Such dyes have vivid hues and a wide color gamut that can be reproduced. On the other hand, water-soluble dyes have drawbacks such as low lightfastness and complicated processes such as fixing and washing after the dye is attached to the fiber, as well as the disposal of waste dye liquid generated by washing. For these reasons, the use of water-insoluble colorants instead of water-soluble dyes has attracted attention.

[0004] In inkjet printing methods using a white pigment as a water-insoluble colorant, a commonly known method is to apply a white pigment ink containing a white pigment to a fabric to form a white base, and then apply color inks to form a color image. In particular, when color inks other than white are directly printed on dark-colored fabrics, including black, the color of the color ink may not be visible to the naked eye. For this reason, when printing color inks on fabrics of colors other than white, a white base is usually formed.

[0005] When forming a color image by applying color inks to a white background, if the whiteness of the background is low, the color development of the color image will be poor. For this reason, it is desirable for the whiteness of the background to be high. To improve color development, it is common to use white pigment inks with high whiteness and hiding power, and inorganic pigments, especially titanium dioxide, are often used as the pigment. However, due to the high specific gravity of inorganic pigments such as titanium dioxide, preventing pigment sedimentation is a challenge, which can lead to problems such as clogging of inkjet nozzles when ejecting ink and poor storage stability of the ink. Although reducing the particle size of titanium dioxide to suppress pigment sedimentation can reduce the sedimentation, this results in a significant decrease in whiteness and hiding power, and therefore there is a strong demand for a white pigment ink that can solve these problems.

[0006] Furthermore, when color inks are applied to a white base to form a color image having solid areas, depending on the combination of white ink and color ink, the color image may have poor rub fastness and wash fastness, resulting in a printed product of poor quality. For this reason, there is a strong demand for an ink set that can solve this problem.

[0007] Patent Documents 1 and 2 disclose inks containing a white pigment. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Special Publication No. 2018-505244 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-31354 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention provides a white pigment ink that has high whiteness, is resistant to sedimentation, and has excellent dispersion stability, and an ink set that can form a color image that has excellent friction resistance and texture when color inks are applied to a base formed with the white pigment ink. [Means for solving the problem]

[0010] As a result of extensive investigations, the present inventors have found that the above-mentioned problems can be solved by a white pigment ink composition for inkjet textile printing, which comprises a white pigment, a polymeric dispersant, a urethane resin, a water-soluble organic solvent, and water, wherein the white pigment has a volume average particle diameter (D50) of 200 to 270 nm, and the water-soluble organic solvent comprises glycerin and a polyhydric alcohol having a boiling point of 215°C or less, and have completed the present invention. That is, the present invention relates to the following 1) to 9). 1) A white pigment ink composition for inkjet textile printing, comprising a white pigment, a polymer dispersant, a urethane resin, a water-soluble organic solvent, and water, wherein the white pigment has a volume average particle diameter (D50) of 200 to 270 nm, and the water-soluble organic solvent comprises glycerin and a polyhydric alcohol having a boiling point of 215°C or less. 2) 1) The white pigment ink composition for ink-jet textile printing according to 1), wherein the polymer dispersant is a polymer composed of at least two types of monomers selected from the group consisting of monomer A, monomer B, and monomer C represented by the following formula (1): Monomer A: A monomer represented by the following formula (1), in which R is a hydrogen atom. Monomer B: A monomer represented by the following formula (1), in which R is a C1-C6 alkyl group. Monomer C: A monomer represented by the following formula (1), in which R is an aryl group or an aryl C1-C4 alkyl group.

[0011] [ka]

[0012] 3) 1) The white pigment ink composition for ink-jet textile printing according to 1) or 2), wherein the polymer dispersant has a weight average molecular weight of 10,000 to 40,000. 4) The white pigment ink composition for ink-jet textile printing according to any one of 1) to 3), wherein the urethane resin contains two types of resins: a polyester-type urethane resin and a polycarbonate-type urethane resin. 5) The white pigment ink composition for ink-jet textile printing according to any one of 1) to 4), which has a static surface tension of 30 to 40 mN / m and a viscosity of 3 to 20 mPa·s at 25°C. 6) An ink set comprising the white pigment ink composition for inkjet textile printing according to any one of 1) to 5), and one or more color ink compositions for inkjet textile printing, each containing a pigment, a block polymer type resin dispersant, a urethane resin, a crosslinking agent, a water-soluble organic solvent, a surfactant, and water. 7) 6) The ink set according to 6), wherein the block polymer type resin dispersant has a weight average molecular weight of 10,000 to 30,000. 8) The ink set according to 6) or 7), wherein the crosslinking agent is a blocked isocyanate group-containing compound. 9) The ink set according to any one of 6) to 8), wherein the urethane resin according to 6) includes two types of resins: a polyester type urethane resin and a polycarbonate type urethane resin. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a white pigment ink that has high whiteness, is resistant to sedimentation, and has excellent dispersion stability, and an ink set that is capable of forming color images that have excellent friction resistance and a texture with little stickiness when color inks are applied to a base formed with the white pigment ink. DETAILED DESCRIPTION OF THE INVENTION

[0014] The best mode for carrying out the present invention will be described in detail below, but the present invention is not limited thereto. Furthermore, unless otherwise specified, "%" and "parts" in this specification, including the examples, are all expressed on a mass basis.

[0015] [White pigment ink composition for inkjet printing] The white pigment ink composition for inkjet textile printing contains a white pigment, a polymer dispersant, a urethane resin, a water-soluble organic solvent, and water, wherein the white pigment has a volume average particle diameter (D50) of 200 to 270 nm, and the water-soluble organic solvent contains glycerin and a polyhydric alcohol having a boiling point of 215° C. or less. Throughout this specification, the "white pigment ink composition for inkjet textile printing" may be abbreviated as "white ink composition."

[0016] The white pigment ink composition for ink-jet textile printing will be described in detail below.

[0017] [White pigment] The white pigment is not particularly limited, and examples thereof include white inorganic pigments such as titanium oxide, zinc oxide, zinc sulfide, antimony oxide, and zirconium oxide; and white organic pigments such as white hollow resin particles and polymer particles; with titanium oxide being preferred. Examples of the crystalline form of titanium oxide include rutile and anatase. The crystalline form of titanium oxide is preferably rutile. Titanium oxide may be used as is as a powder, or may be surface-treated with silicon dioxide, aluminum oxide, zirconia oxide, zinc oxide, or an organic substance having a hydroxyl group. Of these, surface-treated titanium oxide is preferred, and titanium oxide surface-treated with silicon dioxide or aluminum oxide is more preferred. Specific examples include CI Pigment White 1 (basic lead carbonate), CI Pigment White 4 (zinc oxide), CI Pigment White 5 (mixture of zinc sulfide and barium sulfate), CI Pigment White 6 (titanium oxide), CI Pigment White 6:1 (titanium oxide containing other metal oxides), CI Pigment White 7 (zinc sulfide), CI Pigment White 18 (calcium carbonate), CI Pigment White 19 (clay), CI Pigment White 20 (titanium mica), CI Pigment White 21 (barium sulfate), CI Pigment White 22 (natural barium sulfate), CI Pigment White 23 (gloss white), CI Pigment White 24 (alumina white), CI Pigment White 25 (gypsum), CI Pigment White 26 (magnesium oxide and silicon oxide), CI Pigment White 27 (silica), and CI Pigment White 28 (anhydrous calcium silicate).

[0018] Specific examples of titanium oxide include DUAWHITE TCR-52, TITONE R-32, TITONE R-7E, TITONE R-21, TITONE R-62N, and TITONE R-42 (all manufactured by Sakai Chemical Industry Co., Ltd.); TIPAQUE CR-50, TIPAQUE CR-50-2, TIPAQUE CR-58, TIPAQUE CR-60, TIPAQUE CR-80, and TIPAQUE CR-90 (all manufactured by Ishihara Sangyo Kaisha, Ltd.); TITANIX JA-600A and TITANIX JR-605 (all manufactured by Teika Corporation); and ST-455, ST-455WB, ST-457SA, and ST-457EC (all manufactured by Titanium Kogyo Co., Ltd.).

[0019] The white pigment is also available as a dispersion (slurry) in which the pigment is already dispersed. Examples of such dispersions include AC-AW62 (titanium oxide slurry manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., titanium oxide solids concentration: 50%, volume average particle size (D50): 225 nm).

[0020] The volume average particle diameter (D50) of the white pigment is from 200 to 270 nm, preferably from 210 to 260 nm, more preferably from 220 to 250 nm, and even more preferably from 220 to 240 nm, from the viewpoints of storage stability and jetting property.

[0021] [Polymer Dispersant] A method for stabilizing a pigment dispersion in a white ink composition generally involves using a dispersant such as a resin to stabilize the pigment dispersion through entropy, ionic repulsion, steric repulsion, or the like. Here, the dispersant has a hydrophilic portion and a hydrophobic portion, and is considered to have the property that the hydrophobic portion adsorbs to the pigment surface and the hydrophilic portion disperses the pigment in the white ink composition. Furthermore, depending on the state of adsorption to the pigment surface, it is also possible to dissolve the pigment in the white ink composition. A dispersant having such properties can be used as the polymer dispersant.

[0022] The polymer dispersant is preferably a polymer composed of at least two constituent monomers selected from the group consisting of Monomer A, Monomer B, and Monomer C represented by the following formula (1), and more preferably at least one monomer selected from Monomer A, Monomer B, and Monomer C. Monomer A: A monomer represented by the following formula (1), in which R is a hydrogen atom. Monomer B: A monomer represented by the following formula (1), in which R is a C1-C6 alkyl group. Preferably, the monomer is one in which R is an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a cyclopentyl group, or a cyclohexyl group, more preferably, one in which R is an n-butyl group, an isobutyl group, or a cyclohexyl group. Monomer C: A monomer in which R in the following formula (1) is an aryl group or an aryl C1-C4 alkyl group, preferably a monomer in which R is an aryl group, more preferably a monomer in which R is a benzyl group.

[0023] [ka]

[0024] The polymer dispersant may be any of a random copolymer, an alternating copolymer, a block copolymer, and a graft copolymer of these monomers.

[0025] The mass average molecular weight of the polymer dispersant is usually 10,000 to 60,000, preferably 10,000 to 40,000, and more preferably 10,000 to 30,000. When the mass average molecular weight is within this range, the stability of the pigment dispersion liquid is good.

[0026] The acid value of the polymer dispersant, expressed in mgKOH / g, is usually 50 to 300, preferably 90 to 200, and more preferably 100 to 150. If the acid value is too small, the solubility of the polymer dispersant in water or the white ink composition may decrease, and if the acid value is too large, the color development may decrease.

[0027] An example of a polymer dispersant is Seiko PMC's Hi-Loss X VS-1202 (a random polymer consisting of methyl methacrylate, butyl methacrylate and methacrylic acid, with an acid value of 140 mg KOH / g and a mass average molecular weight of 11,000).

[0028] The polymer dispersant may be used after neutralizing its acid value as needed. The degree of neutralization is 100% when the polymer dispersant is neutralized with the theoretical equivalent of its acid value. The degree of neutralization of the polymer dispersant in the ink composition is usually about 50 to 200%, preferably about 80 to 150%, and more preferably about 100 to 120%.

[0029] Examples of the neutralizing agent used to neutralize the polymer dispersant include inorganic bases such as alkali metal hydroxides, alkaline earth metal hydroxides, and ammonia, and organic bases such as aliphatic amine compounds and alkanolamine compounds.

[0030] Examples of the alkali metal hydroxides include lithium hydroxide, sodium hydroxide, potassium hydroxide, etc. Examples of alkaline earth metal hydroxides include beryllium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, etc. Among inorganic bases, alkali metal hydroxides and ammonia are preferred, with lithium hydroxide, sodium hydroxide, and ammonia being particularly preferred.

[0031] Examples of the alkanolamine compound include mono-, di-, or tri-C1-C3 alkanolamine compounds such as monoethanolamine, diethanolamine, triethanolamine, monopropanolamine, dipropanolamine, tripropanolamine, methylethanolamine, dimethylethanolamine, and N-methyldiethanolamine. Among these, tertiary amines are preferred, and triethanolamine is particularly preferred.

[0032] Examples of the aliphatic amine compound include mono-, di-, or tri-C1-C3 amine compounds such as monomethylamine, dimethylamine, trimethylamine, monoethylamine, dimethylamine, trimethylamine, etc. Among these, triethylamine is preferred.

[0033] These neutralizing agents may be used alone or in combination of two or more.

[0034] [Monomer A] Monomer A is a monomer in which R in the above formula (1) is a hydrogen atom, that is, methacrylic acid.

[0035] [Monomer B] Monomer B is a monomer represented by the above formula (1) in which R is a C1-C6 alkyl group. Specific examples of monomer B include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, cyclopentyl methacrylate, and cyclohexyl methacrylate.

[0036] [Monomer C] Monomer C is a monomer represented by the formula (1) in which R is an aryl group or an aryl C1-C4 alkyl group. The aryl group is preferably a C6-C10 aryl group, with a phenyl group or a naphthyl group being particularly preferred. Examples of the aryl C1-C4 alkyl group include phenylmethyl, phenylethyl, phenylpropyl, and phenylbutyl, each of which has a linear or branched alkyl moiety, preferably a linear phenyl C1-C4 alkyl group; naphthylmethyl, naphthylethyl, naphthylpropyl, and naphthylbutyl, each of which has a linear or branched alkyl moiety, preferably a linear naphthyl C1-C4 alkyl group; and the like. Among these, phenyl C1-C4 alkyl groups are preferred. Specific examples of Monomer C include phenyl methacrylate, benzyl methacrylate, and phenethyl methacrylate.

[0037] The content of the polymer dispersant is usually 0.1 to 15.0 mass %, preferably 0.1 to 9.0 mass %, and more preferably 0.2 to 6.0 mass %, relative to the total mass (100 mass %) of the ink composition.

[0038] [Urethane Resin] The urethane resin is a resin having a urethane bond in the molecule. From the viewpoint of storage stability of the ink, the urethane resin is preferably an anionic urethane resin having an acidic group such as a carboxy group, a sulfo group, or a hydroxyl group.

[0039] Examples of the urethane resin include polyether-type urethane resins containing ether bonds in the main chain in addition to urethane bonds, polyester-type urethane resins containing ester bonds in the main chain, and polycarbonate-type urethane resins containing carbonate bonds in the main chain. These urethane resins can be used in combination with multiple types. Among these, from the viewpoint of improving friction resistance, it is preferable to include polyester-type urethane resins and polycarbonate-type urethane resins, and it is more preferable to use a combination of polyester-type urethane resins and polycarbonate-type urethane resins.

[0040] The polyurethane resin may be either a synthetically prepared one or a commercially available product, most of which are emulsions with a solid content of 30 to 60% by mass. Commercially available urethane resin emulsions include, for example, Permarin UA-150, 200, 310, 368, 3945, U-coat UX-320, 390 (all manufactured by Sanyo Chemical Industry Co., Ltd.); Hydran WLS-201, 202, 210, 213, 221, 230, 250, and HW-312B latex (all manufactured by DIC Corporation); Superflex 150, 170, 210, 470, 500M, and 740 (all manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.); ETERNACOLL UW-1005N, UW-1013D, UW-1501F, UW-1527F, and UW-5002 (all manufactured by Ube Industries, Ltd.); and Takelac. Examples of suitable urethane resins include WS-4000, WS-5000, WS-5030, WS-5100, WS-5130, W-6061, W-6110, and WS-5984 (all trade names manufactured by Mitsui Chemicals, Inc.). Examples of suitable polyester urethane resins include Superflex 210, 500M, and 740; Takelac WS-4000, WS-5000, WS-5030, WS-5130, and WS-5984. Examples of suitable polycarbonate urethane resins include Permarin UA-310 and 3945; U-coat UX-320; Hydran WLS-210, 213, and 250; and Takelac W-6110.

[0041] When the urethane resin in the urethane resin emulsion has acidic groups such as carboxyl groups, sulfo groups, or hydroxyl groups, the acidic groups may be converted into alkali salts. For example, the acidic groups can be converted into alkali salts by adding a urethane resin having acidic groups to water and stirring to prepare an aqueous solution, and then adding an alkaline compound to adjust the pH to 6.0 to 12.0. Examples of alkaline compounds include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; and alkaline earth metal hydroxides such as beryllium hydroxide, magnesium hydroxide, calcium hydroxide, and strontium hydroxide. One type of alkaline compound may be used alone, or two or more types may be used in combination.

[0042] [Water-soluble organic solvent] The water-soluble organic solvent contains glycerin and a polyhydric alcohol having a boiling point of 215°C or less.

[0043] The glycerin content is preferably 20% or less of the total ink amount, more preferably 10% to 20% or less, even more preferably 12% to 18% or less, even more preferably 14% to 18% or less, and particularly preferably 15% to 17% or less.

[0044] The polyhydric alcohol having a boiling point of 215°C or less is not particularly limited as long as it has a boiling point of 215°C or less and can be appropriately selected depending on the purpose, and examples thereof include ethylene glycol (bp 197°C), 1,3-butanediol (bp 207°C), 1,2-butanediol (bp 193°C), 2-methyl-1,3-butanediol (bp 214°C), 3-methyl-1,3-butanediol (bp 203°C), propylene glycol (bp 188°C), 1,3-propanediol (bp 213°C), 2-methyl-2,4-pentanediol (bp 197°C), polypropylene glycol (bp 187°C), and 1,2,6-hexanetriol (bp 178°C). These may be used alone or in combination of two or more. Among these, ethylene glycol, 2-methyl-1,3-butanediol, 3-methyl-1,3-butanediol, propylene glycol, and 1,3-propanediol are preferred, 2-methyl-1,3-butanediol, 3-methyl-1,3-butanediol, and 1,3-propanediol are more preferred, and 2-methyl-1,3-butanediol and 3-methyl-1,3-butanediol are even more preferred. The "bp" above represents boiling point.

[0045] The content of the polyhydric alcohol having a boiling point of 215°C or less is preferably 5.0% to 15.0%, more preferably 6.0% to 12.0%, and even more preferably 7.0% to 10.0%. In particular, when the content is 5.0% or more, it is effective in improving rub fastness and suppressing stickiness. Furthermore, when the content is 15.0% or less, high whiteness and hiding power tend to be obtained.

[0046] The water-soluble organic solvent in the present invention may contain water-soluble organic solvents other than the glycerin and the polyhydric alcohol having a boiling point of 215° C. or less (hereinafter, sometimes referred to as other water-soluble organic solvents). Examples of the other water-soluble organic solvents include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, propylene carbonate, ethylene carbonate, etc. These may be used alone or in combination of two or more.

[0047] Examples of the polyhydric alcohol 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, 3-methyl-1,3-butanediol (isoprene glycol), 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 1,5-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, 2,2,4-trimethyl-1,3-pentanediol, and petriol.

[0048] Examples of the polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, and propylene glycol monopropyl ether.

[0049] Examples of the polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

[0050] Examples of the nitrogen-containing heterocyclic compound include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, and γ-butyrolactone.

[0051] Examples of the amides include formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, and 3-butoxy-N,N-dimethylpropionamide.

[0052] These water-soluble organic solvents may be used alone or in combination. Among these, diethylene glycol, 1,2-propanediol, 1,3-propanediol, triethylene glycol, 3-methyl-1,3-butanediol, 1,6-hexanediol, glycerin, diethylene glycol monobutyl ether, and propylene glycol monopropyl ether are preferred, and 1,2-propanediol, 1,3-propanediol, 3-methyl-1,3-butanediol, 1,6-hexanediol, glycerin, and propylene glycol monopropyl ether are more preferred.

[0053] The content of the other water-soluble organic solvent is preferably 1 to 10% by mass, more preferably 1 to 8% by mass, and even more preferably 1 to 6% by mass, relative to the total mass (100% by mass) of the ink composition. When the content of the other water-soluble organic solvent is within the above range, the ink composition tends to be excellent in terms of whiteness, hiding power, rub fastness, and stickiness.

[0054] The total content of the water-soluble organic solvents is preferably 10 to 32% by mass, more preferably 14 to 28% by mass, and even more preferably 16 to 26% by mass, relative to the total mass (100% by mass) of the ink composition. When the total content of the water-soluble organic solvents is within the above range, there is a tendency for the ink composition to be excellent in terms of reducing ejection defects.

[0055] [Water] The white ink composition contains water. The water is not particularly limited, and pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, and distilled water, or ultrapure water can be used. The water content is not particularly limited and can be determined appropriately as needed. However, in order to adjust the solids content by weight in the white ink composition to a suitable range, the water content is preferably 20 to 80% by mass, more preferably 40 to 70% by mass, and particularly preferably 45 to 60% by mass, relative to the total mass (100% by mass) of the white ink composition.

[0056] The white ink composition may further contain additives.

[0057] Examples of the additives include surfactants, preservatives, chelating agents, rust inhibitors, water-soluble ultraviolet absorbers, water-soluble polymer compounds, viscosity adjusters, anti-fading agents, and antioxidants.

[0058] [Surfactant] The surfactant contained in the white ink composition is not particularly limited, and examples thereof include known surfactants such as anionic, cationic, nonionic, amphoteric, silicone, and fluorine-based surfactants. Examples of anionic surfactants include alkyl sulfonates, alkyl carboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, N-acylamino acids and their salts, N-acylmethyl taurines, alkyl sulfates, polyoxyalkyl ether sulfates, alkyl sulfates, polyoxyethylene alkyl ether phosphates, rosin acid soaps, castor oil sulfates, lauryl alcohol sulfates, alkylphenol phosphates, alkyl phosphates, alkylaryl sulfonates, diethyl sulfosuccinates, diethylhexyl sulfosuccinates, and dioctyl sulfosuccinates. Specific examples of commercially available surfactants include Hitenol LA-10, LA-12, and LA-16, and Neohitenol ECL-30S and ECL-45, all manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. Examples of cationic surfactants include 2-vinylpyridine derivatives and poly(4-vinylpyridine) derivatives. Examples of nonionic surfactants include ether surfactants such as polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, and polyoxyethylene alkyl ether; polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, and sorbitan sesquioleate. ester-based surfactants such as polyoxyethylene monooleate and polyoxyethylene stearate; acetylene glycol (alcohol)-based surfactants such as 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol and 3,5-dimethyl-1-hexyn-3-ol; Surfynol 104, 105, 82, 420, 440, 465, Olfin EXP-4001, and the like, manufactured by Nissin Chemical Co., Ltd.; and polyglycol ether-based surfactants (for example, Tergitol 15-S-7, manufactured by SIGMA-ALDRICH).Examples of amphoteric surfactants include lauryl dimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, coconut oil fatty acid amidopropyl dimethylaminoacetic acid betaine, polyoctyl polyaminoethyl glycine, and imidazoline derivatives. Examples of silicone surfactants include polyether-modified siloxanes and polyether-modified polydimethylsiloxanes. Specific examples of commercially available products include BYK-347 (polyether-modified siloxane), BYK-345, and BYK-348 (polyether-modified polydimethylsiloxane), all manufactured by BYK-Chemie. Examples of fluorine-based surfactants include perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylic acid compounds, perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group on the side chain. Specific examples of commercially available products include Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, Capstone FS-30, FS-31 (manufactured by DuPont); PF-151N, PF-154N (manufactured by Omnova), and the like.

[0059] Examples of preservatives in the additives include organic sulfur compounds, organic nitrogen sulfur compounds, organic halogen compounds, haloarylsulfone compounds, iodopropargyl compounds, N-haloalkylthio compounds, nitrile compounds, pyridine compounds, 8-oxyquinolines, benzothiazole compounds, isothiazolinone compounds, dithiols, pyridine oxide compounds, nitropropane compounds, organic tin compounds, phenol compounds, quaternary ammonium salt compounds, triazine compounds, thiazine compounds, anilides, adamantane compounds, dithiocarbamates, brominated indanone compounds, benzyl bromoacetate compounds, and inorganic salt compounds. Specific examples of organic halogen compounds include sodium pentachlorophenol, specific examples of pyridine oxide compounds include sodium 2-pyridinethiol-1-oxide, and specific examples of isothiazoline compounds include 1,2-benzisothiazolin-3-one, 2-n-octyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one magnesium chloride, 5-chloro-2-methyl-4-isothiazolin-3-one calcium chloride, 2-methyl-4-isothiazolin-3-one calcium chloride, etc. Specific examples of other antiseptics and fungicides include sodium acetate anhydride, sodium sorbate, or sodium benzoate, manufactured by Arch Chemical Co., Ltd., under the trade names Proxel RTMGXL(S) and Proxel RTMXL-2(S), etc.

[0060] Specific examples of the chelating agent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uracildiacetate, and the like.

[0061] Examples of the rust inhibitor in the additives include acid sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

[0062] Examples of the water-soluble ultraviolet absorber in the additive include sulfonated benzophenone compounds, benzotriazole compounds, salicylic acid compounds, cinnamic acid compounds, and triazine compounds.

[0063] Examples of the water-soluble polymer compound in the additive include polyvinyl alcohol, cellulose derivatives, polyamines, and polyimines.

[0064] Examples of the viscosity adjuster in the additives include the water-soluble organic solvents and water-soluble polymer compounds described in the section on the water-based ink composition. Examples of the water-soluble polymer compounds include polyvinyl alcohol, cellulose derivatives, polyamines, and polyimines.

[0065] The anti-fading agent in the above additives is used for the purpose of improving the storage stability of images. As the anti-fading agent, for example, various organic and metal complex anti-fading agents can be used. Examples of organic anti-fading agents include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, and heterocycles. Examples of metal complex anti-fading agents include nickel complexes and zinc complexes.

[0066] The antioxidant in the additives may be, for example, various organic and metal complex anti-fading agents, such as hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, and heterocycles.

[0067] [Static Surface Tension of White Ink Composition] The static surface tension of the white ink composition at 25°C is preferably 30 to 45 mN / m, more preferably 32 to 42 mN / m, even more preferably 33 to 41 mN / m, and particularly preferably 35 to 40 mN / m, from the viewpoint of being able to exhibit sufficient wettability to various fabrics.

[0068] The static surface tension of the white ink composition can be measured by the platinum plate method in a 25° C. environment using, for example, a surface tensiometer (CBVPZ manufactured by Kyowa Interface Science Co., Ltd.).

[0069] [Dynamic surface tension of white ink composition] The dynamic surface tension of the white ink composition at 25° C. is preferably 46 mN / m or more, and more preferably 48 mN / m or more.

[0070] The dynamic surface tension of the white ink composition can be measured using a dynamic surface tensiometer. The dynamic surface tension value is measured at 25°C when the surface life measured by the maximum bubble pressure method is 15 ms.

[0071] [Viscosity of White Ink Composition] The viscosity of the white ink composition at 25° C. is preferably 2 to 20 mPa·s, and more preferably 3 to 18 mPa·s. If the water-based ink composition satisfies the above viscosity range, the ejection response tends to be good during high-speed printing.

[0072] [Method for Preparing White Ink Composition] Examples of methods for preparing the white ink composition include preparing an aqueous dispersion containing the above components, and, if necessary, further adding additives such as a water-soluble organic solvent.

[0073] [Ink set] The present invention also includes an ink set containing the above white ink composition and a color ink composition for ink-jet textile printing. The inkjet printing color ink composition is preferably a water-based ink composition containing a pigment, a block polymer type resin dispersant, a urethane resin, a crosslinking agent, a water-soluble organic solvent, a surfactant, and water. In this specification, the inkjet printing color ink composition may be abbreviated as a water-based ink composition or a color ink.

[0074] The ink set according to this embodiment includes the white ink composition described above, and therefore can obtain images with high whiteness and high hiding power, and can also improve color development, rub fastness, and wash fastness.

[0075] The water-based ink composition will now be described in detail.

[0076] [Pigment] The pigment is not particularly limited as long as it is a white pigment, and any known pigment can be used. Known pigments include inorganic pigments, organic pigments, and extender pigments.

[0077] Examples of the inorganic pigment include carbon black, metal oxides, hydroxides, sulfides, ferrocyanides, metal chlorides, etc. Among these, carbon black is preferred as a black pigment. There are several types of carbon black, including, for example, thermal black and acetylene black obtained by pyrolysis; and oil furnace black, gas furnace black, lamp black, gas black, and channel black obtained by incomplete combustion.

[0078] Of the above, preferred carbon blacks include acetylene black, oil furnace black, gas furnace black, lamp black, and channel black. Specific examples of carbon black include Raven 760 ULTRA, Raven 780 ULTRA, Raven 790 ULTRA, Raven 1060 ULTRA, Raven 1080 ULTRA, Raven 1170, Raven 1190 ULTRA II, Raven 1200, Raven 1250, Raven 1255, Raven 1500, Raven 2000, Raven 2500 ULTRA, Raven 3500, Raven 5000 ULTRA II, Raven 5250, Raven 5750, and Raven 7000 (all manufactured by Columbia Carbon); Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, Regal 1330R, Regal 1400R, Regal 1660R, and Mogul L (all manufactured by Cabot Corporation); Color Black FW1, Color Black FW2, Color Black FW2V, Color Black FW200, Color Black S150, Color Black S160, Color Black S170, Printex 35, Printex U, Printex V, Printex 140U, Printex 140V, SpecIal Black 4, SpecIal Black 4A, SpecIal Black 5, Special Black 6 (all manufactured by Degussa); MA7, MA8, MA100, MA600, MCF-88, No. 25, No. 33, No. 40, No. 47, No. 52, No. 900, No. 2300 (all manufactured by Mitsubishi Chemical Corporation); and the like.

[0079] Examples of the organic pigment include azo pigments having at least one azo group in the molecule, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, dioxazine pigments, perylene pigments, perinone pigments, thioindigo pigments, anthraquinone pigments, and quinophthalone pigments. Specific examples of organic pigments include yellow pigments such as CI Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 24, 55, 73, 74, 75, 83, 93, 94, 95, 97, 98, 108, 114, 128, 129, 138, 139, 150, 151, 154, 155, 180, 185, 193, 199, and 202; and CI Pigment Red Red pigments such as 5, 7, 12, 48, 48:1, 57, 88, 112, 122, 123, 146, 149, 166, 168, 177, 178, 179, 184, 185, 202, 206, 207, 254, 255, 257, 260, 264, and 272; blue pigments such as CI Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 22, 25, 60, 66, and 80; violet pigments such as CI Pigment Violet 19, 23, 29, 37, 38, and 50; orange to brown pigments such as CI Pigment Orange 13, 16, 36, 34, 43, 68, 69, 71, and 73; and CI Pigment Green pigments such as Green 7, 36, and 54; black pigments such as CI Pigment Black 1; and the like.

[0080] Examples of the extender pigment include silica, calcium carbonate, talc, clay, barium sulfate, white carbon, etc. These extender pigments may be used alone, but are usually used in combination with inorganic or organic pigments.

[0081] A single pigment is usually used as the pigment. However, two or more pigments may be used in combination if necessary. Examples include a combination of an organic pigment and an extender pigment, or an organic pigment and an inorganic pigment. To improve flowability, an extender pigment may be used in addition to an organic pigment and an inorganic pigment. Furthermore, to adjust the hue of a dyed product, two or more pigments selected from inorganic and organic pigments may be used in combination. The hue adjustment here is performed for the purposes of obtaining a dyed product with a different shade, widening the color gamut of the dye, etc. For such purposes, several organic pigments may be used in combination to adjust the desired hue.

[0082] The content of the pigment is preferably 1.5 to 15.0 mass %, more preferably 2.0 to 14.0 mass %, and even more preferably 2.5 to 13.0 mass %, relative to the total mass (100 mass %) of the ink composition.

[0083] [Block polymer type resin dispersant] Block polymer dispersants are copolymers formed by chemically bonding two or more blocks, each consisting of at least one type of addition-polymerizable monomer. When the block is composed of multiple monomers, the order of bonding the multiple monomers can be arbitrary. For example, if a block is composed of monomer A and monomer B, the bonding order can be "AAA, BBB," "ABABAB," or any other order.

[0084] The block polymer resin dispersant may be an alternating copolymer, a block copolymer, or a graft copolymer of monomers, and may be synthesized or commercially available.

[0085] Examples of block polymer resin dispersants obtained by synthesis include the AB block polymers disclosed in WO 2013 / 115071 and WO 2022 / 025166.

[0086] The monomer constituting the A block of the AB block polymer disclosed in WO 2013 / 115071 is at least one monomer selected from (meth)acrylic acid and a linear or branched C4 alkyl (meth)acrylate, preferably at least one monomer selected from methacrylic acid and n-butyl methacrylate, and more preferably a combination of these two monomers. The monomer constituting the B block of the AB block polymer disclosed in WO 2013 / 115071 is at least one monomer selected from benzyl methacrylate and benzyl acrylate, preferably benzyl methacrylate. Specific examples include the block copolymers disclosed in Synthesis Examples 3 to 8 of WO 2013 / 115071.

[0087] The monomers constituting the A block of the AB block polymer disclosed in WO 2022 / 025166 are (meth)acrylic acid and butyl (meth)acrylate, with a combination of methacrylic acid and n-butyl methacrylate being preferred. The content of (meth)acrylic acid in the total mass of the monomers constituting the A block is typically 26 to 42 mass%, preferably 31 to 40 mass%. Furthermore, the monomers constituting the B block of the AB block polymer disclosed in WO 2022 / 025166 include cyclohexyl (meth)acrylate, preferably cyclohexyl methacrylate. The content of cyclohexyl (meth)acrylate in the total mass of the monomers constituting the B block is typically 80 to 100 mass%, preferably 90 to 99.8 mass%. The monomers constituting the B block may include (meth)acrylic acid as an additional monomer. The content of (meth)acrylic acid in the total mass of the monomers constituting the B block is usually 0.1 to 10% by mass, preferably 0.5 to 5% by mass. Specific examples include the block copolymers disclosed in Synthesis Examples 1 to 10, 18, and 19 of WO 2022 / 025166. Commercially available block polymer resin dispersants include, for example, BYK's DISPERBYK 2010 (acid value: 20 mg KOH / g, amine value: 20 mg KOH / g), 2012 (acid value: 7 mg KOH / g, amine value: 7 mg KOH / g), 2015 (acid value: 10 mg KOH / g), BYKJET-9151 (acid value: 8 mg KOH / g, amine value: 18 mg KOH / g), and 9171 (amine value: 28 mg KOH / g), and BASF's DIspex Uit ra PX. 4575 (amine value: 32 mg KOH / g), 4585 (amine value: 20 mg KOH / g); AFCONA-4597 (acid value: 10 mg KOH / g, amine value: 13 mg KOH / g) and 4598 (acid value: 11 mg KOH / g) manufactured by AFCONA;

[0088] The weight-average molecular weight of the block polymer type resin dispersant is usually 10,000 to 40,000, preferably 10,000 to 30,000, and more preferably 15,000 to 25,000. When the weight-average molecular weight is in the range of 10,000 to 40,000, the stability of the pigment dispersion liquid is good. The weight-average molecular weight of the dispersant can be measured by gel permeation chromatography (GPC), specifically using a GPC apparatus HLC-8320 (manufactured by Tosoh Corporation), two columns TSK gel Super Muitipore HZ-H (manufactured by Tosoh Corporation, inner diameter 4.6 mm x 15 cm), tetrahydrofuran as an eluent, and TSK Standard (manufactured by Tosoh Corporation) as a standard sample.

[0089] The acid value of the block polymer type resin dispersant is, in mgKOH / g, usually 50 to 300, preferably 90 to 200, and more preferably 100 to 150. If the acid value is too small, the solubility of the polymer dispersant in water or the white ink composition decreases, and if the acid value is too large, the color development properties may decrease.

[0090] The ink according to this embodiment preferably contains pigment particles in which at least a portion of the surface is coated with a block polymer resin dispersant. In this case, the average particle diameter (D50) of the particles is typically 200 nm or less, preferably 50 to 200 nm, more preferably 70 to 170 nm, and even more preferably 80 to 150 nm, from the viewpoints of storage stability and jetting performance. In addition to D50, D90 and D10 may also be preferably measured in some cases. The D90 (the cumulative 90% value calculated from the small particle side in the frequency distribution of scattering intensity) of the particles coated with a dispersant is usually 300 nm or less, preferably 250 nm or less, more preferably 240 nm or less, from the viewpoint of reducing coarse particles and improving the storage stability of the dispersion. The lower limit is preferably 100 nm or more, from the viewpoint of ease of production. The D10 (the cumulative 10% value calculated from the small particle side in the frequency distribution of scattering intensity) of the particles coated with a dispersant is usually 10 nm or more, preferably 20 nm or more, and more preferably 30 nm or more and 50 nm or less, from the viewpoint of print density when made into an ink composition and ease of production.

[0091] The content of the block polymer type resin dispersant is preferably 0.1 to 1.0 times, more preferably 0.2 to 0.8 times, and even more preferably 0.25 to 0.7 times the content of the pigment on a mass basis.

[0092] The block polymer type resin dispersant may be used after neutralizing its acid value as needed. The degree of neutralization is 100% when the block polymer type resin dispersant is neutralized with the theoretical equivalent of its acid value. The degree of neutralization of the polymer dispersant in the ink composition is usually about 50 to 200%, preferably about 80 to 150%, and more preferably about 100 to 120%.

[0093] Examples of the neutralizing agent used to neutralize the block polymer type resin dispersant include inorganic bases such as alkali metal hydroxides, alkaline earth metal hydroxides, and ammonia, and organic bases such as aliphatic amine compounds and alkanolamine compounds.

[0094] Examples of the alkali metal hydroxides include lithium hydroxide, sodium hydroxide, potassium hydroxide, etc. Examples of alkaline earth metal hydroxides include beryllium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, etc. Among inorganic bases, alkali metal hydroxides and ammonia are preferred, with lithium hydroxide, sodium hydroxide, and ammonia being particularly preferred.

[0095] Examples of the alkanolamine compound include mono-, di-, or tri-C1-C3 alkanolamine compounds such as monoethanolamine, diethanolamine, triethanolamine, monopropanolamine, dipropanolamine, tripropanolamine, methylethanolamine, dimethylethanolamine, and N-methyldiethanolamine. Among these, tertiary amines are preferred, and triethanolamine is particularly preferred.

[0096] Examples of the aliphatic amine compound include mono-, di-, or tri-C1-C3 amine compounds such as monomethylamine, dimethylamine, trimethylamine, monoethylamine, dimethylamine, trimethylamine, etc. Among these, triethylamine is preferred.

[0097] These neutralizing agents may be used alone or in combination of two or more.

[0098] [Urethane resin] The urethane resin that can be contained in the water-based ink composition may be the same as that described for the white ink composition, including preferred examples. Furthermore, the urethane resin that can be contained in the water-based ink composition and the urethane resin contained in the white ink composition may be the same or different from each other.

[0099] [Crosslinking agent] The water-based pigment textile printing ink composition contains a crosslinking agent. Examples of the crosslinking agent include, but are not limited to, a blocked isocyanate group-containing compound, an epoxy group-containing compound, an oxazoline group-containing compound, a carbodiimide group-containing compound, a methylol group-containing compound, a cyclocarbonate group-containing compound, an azirinyl group-containing compound, an acetoacetyl group-containing compound, and a silanol group-containing compound. These crosslinking agents may be used alone or in combination. Among these, a carbodiimide group-containing compound, an oxazoline group-containing compound, a blocked isocyanate group-containing compound, and an epoxy group-containing compound are preferred from the viewpoint of improving water resistance. It is more preferred to include a compound selected from the group consisting of a blocked isocyanate group-containing compound, an oxazoline group-containing compound, and a carbodiimide group-containing compound. It is particularly preferred to include a compound selected from the group consisting of a blocked isocyanate group-containing compound and an oxazoline group-containing compound. The compound may be either a water-soluble compound or a water-dispersible compound, but is preferably a water-dispersible compound from the viewpoint of storage stability. In the present invention, the term "blocked isocyanate group-containing compound" refers to a compound in which the isocyanate group in a polyisocyanate compound is blocked with a blocking agent.

[0100] The blocked isocyanate group-containing compound refers to a polyisocyanate compound in which the isocyanate group has been blocked with a blocking agent. Blocking the highly reactive isocyanate group stabilizes the isocyanate group, improving the storage stability of the aqueous composition while enabling the formation of a strong ink film after the crosslinking reaction. The polyisocyanate compound is a compound having two or more isocyanate groups per molecule. Examples of such polyisocyanate compounds include aliphatic isocyanates, alicyclic isocyanates, araliphatic isocyanates, aromatic isocyanates, and modified versions of these. Modified polyisocyanate compounds include polymers such as isocyanurates; biuret compounds; and adducts of trimethylolpropane and pentaerythritol with polyhydric alcohols.

[0101] The aliphatic isocyanate is preferably, for example, a diisocyanate having a linear or branched aliphatic hydrocarbon group between two isocyanate groups. The carbon number of the aliphatic hydrocarbon group is preferably 2 or more, more preferably 3 or more, and preferably 10 or less, more preferably 9 or less, and even more preferably 8 or less. Specific examples include tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (HDI), heptamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4- or 2,4,4-trimethylhexamethylene diisocyanate, etc. Examples of the alicyclic isocyanate include hydrogenated xylylene diisocyanate (H6XDI), 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate (H12MDI), isophorone diisocyanate (IPDI), 2,5- or 2,6-norbornane diisocyanate, etc. Examples of the araliphatic isocyanate include m- or p-xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), etc. Examples of the aromatic isocyanate include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate (TDI), 4,4'- or 2,4'-diphenylmethane diisocyanate (MDI), m- or p-isocyanatophenylsulfonyl isocyanate, 4,4'-diisocyanatobiphenyl, 4,4'-diisocyanato-3,3'-dimethylbiphenyl, 1,5-naphthylene diisocyanate, and 2,6-dimethylbenzene-1,4-diisocyanate.

[0102] Examples of the blocking agent include compounds having active hydrogen, such as amines such as 3,5-dimethylpyrazole (DMP), 1,2,4-triazole, and diisopropylamine; phenols such as phenol and cresol; oximes such as methyl ethyl ketoxime; lactams such as ε-caprolactam; and active methylene compounds such as diethyl malonate and ethyl acetoacetate. Among these, 3,5-dimethylpyrazole (DMP) is preferred from the viewpoints of stability, yellowing resistance, and safety.

[0103] The dissociation temperature of the blocked isocyanate group-containing compound is preferably 120°C or higher, more preferably 125°C or higher, from the viewpoints of storage stability, friction fastness, and adhesion. At 120°C or higher, the storage stability of the ink composition tends to be improved. Furthermore, from the viewpoint of suppressing damage such as deformation of the recording medium, the dissociation temperature is preferably 150°C or lower, more preferably 130°C or lower. In particular, when polyester or a blend containing polyester is used for the fabric, the drying step after printing must be carried out at a drying temperature of 130°C or lower to prevent dye migration (hereinafter also simply referred to as dye transfer), so a dissociation temperature of 130°C or lower is preferred.

[0104] Commercially available blocked isocyanate group-containing compounds include, for example, Trixene blocked isocyanates Aqua BI200, Aqua BI220, 7950, 7951, 7960, 7961, 7982, 7990, 7991, and 7992 (all of which are trade names manufactured by Baxenden); DM-6400, Meikanate DM-3031CONC, Meikanate DM-35HC, Meikanate TP-10, Meikanate ST, Meikanate PRO, NBP-873D, Meikanate NS-1, and Meikanate DX (all of which are trade names manufactured by Meisei Chemical Industry Co., Ltd.); Elastron BN-69, Examples include BN-77, BN-27, and BN-11 (all trade names, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.); Takenate WB-700, WB-770, and WB-920 (all trade names, manufactured by Mitsui Chemicals, Inc.); Duranate MF-K60B, SBN-70D, MF-B60B, MF-B90B, 17B-60P, TPA-B80B, TPA-B80E, and E402-B80B (all trade names, manufactured by Asahi Kasei Corporation); Fixer N (all trade names, manufactured by Matsui Dye Chemical Research Institute Co., Ltd.); and Bayhydur BL2867 (all trade names, manufactured by Sumika Covestro Urethane Co., Ltd.).

[0105] From the viewpoints of the storage stability, abrasion fastness, and washing fastness of the ink composition, the carbodiimide group-containing compound is preferably a polycarbodiimide compound containing two or more carbodiimide groups per molecule. As the carbodiimide group-containing compound, for example, a compound obtained by capping the terminal isocyanate group of a condensation reaction product obtained by a decarboxylation condensation reaction of diisocyanates in the presence of a carbodiimidization catalyst with a hydrophilic group is preferred.

[0106] Examples of diisocyanates used in the decarboxylation condensation reaction include aliphatic diisocyanates such as hexamethylene diisocyanate (HDI), decamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate; 4,4'-dicyclohexylmethane diisocyanate (H12MDI), isophorone diisocyanate (IPDI), 2,5- or 2,6-norbornane diisocyanate, hydrogenated xylylene diisocyanate (H6XDI), hydrogenated tolylene diisocyanate, and 2,4-bis-(8 alicyclic diisocyanates such as (-isocyanatooctyl)-1,3-dioctylcyclobutane (OCDI); araliphatic diisocyanates such as m- or p-xylylene diisocyanate (XDI) and tetramethylxylylene diisocyanate (TMXDI); and aromatic diisocyanates such as 2,4,6-triisopropylphenyl diisocyanate (TIDI), 4,4'- or 2',4-diphenylmethane diisocyanate (MDI), and 2,4- or 2,6-tolylene diisocyanate (TDI).

[0107] The compound obtained by capping the terminal isocyanate group of the condensation reaction product with a hydrophilic group is a compound having a functional group capable of reacting with the isocyanate group, such as polyethylene glycol monomethyl ether or polypropylene glycol monomethyl ether. Among these, polyethylene glycol monomethyl ether is preferred from the viewpoints of the compatibility of the carbodiimide group-containing compound with the ink composition and the storage stability of the ink composition. The number of moles of ethylene oxide added to the polyethylene glycol monomethyl ether can be adjusted, and the resulting carbodiimide group-containing polymer can be incorporated into the aqueous composition in the form of an emulsion or aqueous solution.

[0108] From the viewpoints of storage stability, friction fastness, and washing fastness of the ink, the carbodiimide group-containing compound is preferably blended into the ink composition as an aqueous solution or emulsion, and from the viewpoint of storage stability of the ink, it is preferably blended into the ink as an aqueous solution. Commercially available examples of the carbodiimide group-containing compound include Carbodilite E-02, Carbodilite E-03A, Carbodilite E-05, Carbodilite V-02, Carbodilite V-02-L2, and Carbodilite V-04 (all of which are trade names manufactured by Nisshinbo Chemical Inc.).

[0109] From the viewpoint of storage stability, abrasion fastness, and washing fastness of the ink, the oxazoline group-containing compound is preferably a polyoxazoline compound having two or more oxazoline groups in one molecule.

[0110] Commercially available oxazoline group-containing compounds include, for example, the "Epocross WS series" such as "Epocross WS-300," "Epocross WS-500," and "Epocross WS-700" (all manufactured by Nippon Shokubai Co., Ltd., water-soluble types); and the "Epocross K series" such as Epocross K-2010E and Epocross K-2020E (trade names, emulsion types, manufactured by Nippon Shokubai Co., Ltd.).

[0111] The content of the crosslinking agent is 0.1% by mass or more and less than 4.0% by mass, preferably 0.2 to 3.5% by mass, more preferably 0.4 to 3.0% by mass, and even more preferably 0.6 to 2.7% by mass, relative to the total mass of the ink. If it is 0.1% by mass or more, effective adhesion tends to be obtained. If it is 4.0% by mass or less, the storage stability of the ink tends to be excellent.

[0112] Examples of water-soluble organic solvents that can be contained in the aqueous ink composition include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, propylene carbonate, ethylene carbonate, etc. These may be used alone or in combination of two or more. The water-soluble organic solvents that may be contained in the aqueous ink composition, such as polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, and amides, may be the same as those described above for the white ink composition, including preferred examples. Furthermore, the water-soluble organic solvents that may be contained in the aqueous ink composition and the water-soluble organic solvent contained in the white ink composition may be the same or different.

[0113] From the viewpoints of drying properties and ejection stability, the water-soluble organic solvent that can be contained in the aqueous ink composition includes a polyhydric alcohol having a boiling point of 250°C or higher and a polyhydric alcohol having a boiling point of 215°C or lower, and the content of the polyhydric alcohol having a boiling point of 250°C or higher is preferably 20% or less, and more preferably 18% or less, of the total amount of ink.

[0114] Examples of the polyhydric alcohol having a boiling point of 250° C. or higher include glycerin (boiling point: 290° C.).

[0115] Examples of polyhydric alcohols having a boiling point of 215° C. or less include those exemplified in the white ink composition. Furthermore, although not limited to these, preferred examples include ethylene glycol, 2-methyl-1,3-butanediol, 3-methyl-1,3-butanediol, propylene glycol, and 1,3-propanediol.

[0116] The content of the water-soluble organic solvent that can be contained in the water-based ink composition is preferably 10 to 50 mass %, more preferably 14 to 45 mass %, and even more preferably 16 to 35 mass %, relative to the total mass (100 mass %) of the water-based ink composition. When the content of the water-soluble organic solvent that can be contained in the water-based ink composition is within the above range, the water-based ink composition tends to be excellent in terms of reducing ejection defects.

[0117] [Surfactants] The surfactant that can be contained in the water-based ink composition is not particularly limited, but examples thereof include known surfactants such as anionic, cationic, nonionic, amphoteric, silicone, and fluorine-based surfactants. Examples of anionic surfactants include alkyl sulfonates, alkyl carboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, N-acylamino acids and their salts, N-acylmethyltaurines, alkyl sulfates, polyoxyalkyl ether sulfates, alkyl sulfates, polyoxyethylene alkyl ether phosphates, rosin acid soaps, castor oil sulfates, lauryl alcohol sulfates, alkylphenol phosphates, alkyl phosphates, alkylaryl sulfonates, diethyl sulfosuccinates, diethylhexyl sulfosuccinates, dioctyl sulfosuccinates, etc. Specific examples of commercially available products include Hitenol LA-10, LA-12, LA-16, Neohitenol ECL-30S, and ECL-45, all manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. Examples of cationic surfactants include 2-vinylpyridine derivatives and poly(4-vinylpyridine) derivatives. Examples of nonionic surfactants include ether surfactants such as polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, and polyoxyethylene alkyl ether; polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, and sorbitan sesquioleate. ester-based surfactants such as polyoxyethylene monooleate and polyoxyethylene stearate; acetylene glycol (alcohol)-based surfactants such as 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol and 3,5-dimethyl-1-hexyn-3-ol; Surfynol 104, 105, 82, 420, 440, 465, Olfin EXP-4001, and the like, manufactured by Nissin Chemical Co., Ltd.; and polyglycol ether-based surfactants (for example, Tergitol 15-S-7, manufactured by SIGMA-ALDRICH). Examples of amphoteric surfactants include lauryl dimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, coconut oil fatty acid amidopropyl dimethylaminoacetic acid betaine, polyoctyl polyaminoethyl glycine, and imidazoline derivatives. Examples of silicone surfactants include polyether-modified siloxane, polyether-modified polydimethylsiloxane, etc. Specific examples of commercially available products include BYK-347 (polyether-modified siloxane), BYK-345, and BYK-348 (polyether-modified polydimethylsiloxane), all manufactured by BYK-Chemie. Examples of fluorine-based surfactants include 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 on the side chains. Specific examples of commercially available products include Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, Capstone FS-30, FS-31 (manufactured by DuPont); PF-151N, PF-154N (manufactured by Omnova).

[0118] [water] The water that can be contained in the aqueous ink composition can be, for example, the same as those exemplified for the white ink composition. The content of water that can be contained in the aqueous ink composition is not particularly limited and can be determined appropriately as needed, but in order to adjust the viscosity of the aqueous ink composition within a suitable range, it is preferable that the content of water be 40 to 80% by mass relative to the total mass (100% by mass) of the aqueous ink composition. Furthermore, although not limited thereto, the content is preferably 45 to 75% by mass, more preferably 50 to 70% by mass, and even more preferably 55 to 65% by mass.

[0119] The water-based ink composition may further contain an additive B.

[0120] Examples of the additive B include preservatives, chelating agents, anti-rust agents, water-soluble ultraviolet absorbers, water-soluble polymer compounds, viscosity modifiers, anti-fading agents, and antioxidants.

[0121] Examples of the preservative in Additive B include organic sulfur compounds, organic nitrogen sulfur compounds, organic halogen compounds, haloarylsulfone compounds, iodopropargyl compounds, N-haloalkylthio compounds, nitrile compounds, pyridine compounds, 8-oxyquinolines, benzothiazole compounds, isothiazolinone compounds, dithiols, pyridine oxide compounds, nitropropane compounds, organic tin compounds, phenol compounds, quaternary ammonium salt compounds, triazine compounds, thiazine compounds, anilides, adamantane compounds, dithiocarbamates, brominated indanone compounds, benzyl bromoacetate compounds, and inorganic salt compounds. Specific examples of organic halogen compounds include sodium pentachlorophenol, specific examples of pyridine oxide compounds include sodium 2-pyridinethiol-1-oxide, and specific examples of isothiazoline compounds include 1,2-benzisothiazolin-3-one, 2-n-octyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one magnesium chloride, 5-chloro-2-methyl-4-isothiazolin-3-one calcium chloride, 2-methyl-4-isothiazolin-3-one calcium chloride, etc. Specific examples of other antiseptics and fungicides include sodium acetate anhydride, sodium sorbate, or sodium benzoate, manufactured by Arch Chemical Co., Ltd., under the trade name Proxel. RTM GXL(S) and Proxel RTM Examples include XL-2(S).

[0122] Specific examples of the chelating agent in the additive B include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, and sodium uracildiacetate.

[0123] Examples of the rust inhibitor in the additive B include acid sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

[0124] Examples of the water-soluble ultraviolet absorber in Additive B include sulfonated benzophenone compounds, benzotriazole compounds, salicylic acid compounds, cinnamic acid compounds, and triazine compounds.

[0125] Examples of the water-soluble polymer compound in the additive B include polyvinyl alcohol, cellulose derivatives, polyamines, and polyimines.

[0126] Examples of the viscosity adjuster in Additive B include the water-soluble organic solvents and water-soluble polymer compounds described in the section on the water-based ink composition above. Examples of the water-soluble polymer compounds include polyvinyl alcohol, cellulose derivatives, polyamines, and polyimines.

[0127] The anti-fading agent in Additive B is used to improve the storage stability of images. Examples of the anti-fading agent include various organic and metal complex anti-fading agents. Examples of organic anti-fading agents include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, and heterocycles. Examples of metal complex anti-fading agents include nickel complexes and zinc complexes.

[0128] For example, various organic and metal complex anti-fading agents can be used as the antioxidant in Additive B. Examples of the organic anti-fading agents include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, and heterocycles.

[0129] [Static surface tension of water-based ink composition] The static surface tension of the water-based ink composition at 25°C is preferably 30 to 40 mN / m, more preferably 32 to 39 mN / m, even more preferably 33 to 38 mN / m, and particularly preferably 34 to 37 mN / m, from the viewpoint of being able to exhibit sufficient wettability to various fabrics.

[0130] The static surface tension of the water-based ink composition can be measured, for example, by a platinum plate method using a surface tensiometer (CBVPZ manufactured by Kyowa Interface Science Co., Ltd.) in a 25°C environment.

[0131] [Viscosity of Water-Based Ink Composition] The viscosity of the water-based ink composition at 25° C. is preferably 2 to 20 mPa·s, and more preferably 3 to 18 mPa·s. Water-based ink compositions that satisfy the above viscosity range tend to exhibit good ejection response during high-speed printing.

[0132] [Method for preparing water-based ink composition] The water-based ink composition can be prepared, for example, by preparing an aqueous dispersion containing the above components, and, if necessary, further adding additives such as a water-soluble organic solvent that can be contained in the water-based ink composition.

[0133] [Recording Media] The white ink composition and ink set of the present invention are capable of forming very good images on textile fabrics.

[0134] [Fabric] Fabrics include fibers and refer to fabrics that are woven, knitted, nonwoven, or other forms of fibers. Examples of fibers constituting the fabric include fibers selected from the group consisting of polyester, cellulose, polyamide, and natural fibers. Examples of polyester fibers include fibers primarily composed of polyethylene terephthalate. Examples of cellulose fibers include cotton, rayon, triacetate fibers, and diacetate fibers. Examples of polyamide fibers include nylon fibers. Examples of natural fibers include silk and wool. The above fibers may be fibers of a single material or blends of these materials. Furthermore, these fibers may be provided with an ink-receiving layer (bleed-preventing layer).

[0135] The color of the fabric may be any dark or light color, and the white ink composition may be applied to a white fabric if desired.

[0136] [Dark fabric] The dark colored fabric means a fabric other than white. Specific examples include black, gray, navy blue, red, blue, green, and other fabrics. The lightness (L * ) using a spectrophotometer (e.g., X-rite exact (manufactured by X-rite)), * It is preferable that the fabric satisfies the range of 40>L * It is more preferable that the fabric satisfies the range of 30>L * It is more preferable that the fabric satisfies the range of 20>L * It is particularly preferable that the fabric satisfies the range.

[0137] The white ink composition according to this embodiment has high whiteness and hiding power when a base is laid using the white ink composition, and high-quality white printed textiles can be obtained. In addition, the dispersion stability is also excellent. Because the whiteness and hiding power of the base can be increased, the color development of an image printed on the base using the aqueous ink composition can be improved, and a printed material having a high-quality color image can be obtained. Furthermore, the printed textiles obtained using the ink set of the present invention also have excellent fastness properties such as rub fastness and wash fastness. [Example]

[0138] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples. The white pigment ink composition for inkjet textile printing and the color ink compositions for inkjet textile printing were prepared under stirring unless otherwise specified. The "water" used in the examples is ion-exchanged water.

[0139] <Preparation of dispersion liquid> [Preparation Example 1]: Preparation of Dispersion 1 Polymer dispersant A was obtained by reproducing Synthesis Example 3 of WO 2013 / 115071. The acid value of the obtained polymer dispersant A was 104 mg KOH / g and the weight-average molecular weight was 22,000. The obtained polymer dispersant A (6.0 parts) was dissolved in 2-butanone (30.0 parts) to obtain a uniform solution. To this solution, 25% aqueous sodium hydroxide solution (1.8 parts), DF58 (0.6 parts), and ion-exchanged water (54.3 parts) were added and stirred for 1 hour to obtain an emulsion in which the polymer dispersant was dissolved. Typepaque CR-60-2 (60.0 parts, manufactured by Ishihara Sangyo Kaisha) was added to this emulsion, and the mixture was dispersed in a sand grinder at 1500 rpm for 10 hours. Ion-exchanged water (40.0 parts) was added dropwise to the obtained liquid, and the dispersion beads were removed by filtration. Then, 2-butanone and a portion of the water were distilled off under reduced pressure using an evaporator with a water bath temperature of 55°C, to obtain Dispersion Liquid 1 with a pigment solids content of 40%. [Preparation Example 2]: Preparation of Dispersion 2 Dispersion liquid 2 was obtained in the same manner as in Preparation Example 1, except that TIPAQUE R-960 was used as the white pigment instead of TIPAQUE CR-60-2.

[0140] [Examples 1 to 5 and Comparative Example 1]: Preparation of white pigment ink composition The components listed in Table 1 below were mixed by thorough stirring, filtered through a mixed cellulose ester filter with a pore size of 5 μm, and then degassed using a vacuum pump to prepare white pigment ink compositions (W1 to 6).

[0141] The descriptions in Table 1 below indicate the following: The numerical values ​​in Table 1 are in parts. AC-AW62 (white pigment dispersion, 50% solids, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.) Takelac W-5130 (polyester-type urethane resin emulsion, solids content 35%, manufactured by DIC Corporation) Takelac W-6110 (polycarbonate-type urethane resin emulsion, solids content 32%, manufactured by DIC Corporation) Hydran WLS-210 (polycarbonate-type urethane resin emulsion, solids content 35%, manufactured by DIC Corporation) PROXEL GXL(S) (preservative, manufactured by Lonza Corporation) TEA: Triethanolamine manufactured by Junsei Chemical Co., Ltd. BYK-349 (surfactant, manufactured by BYK Japan)

[0142] [Table 1]

[0143] <Physical Properties of White Pigment Ink Composition> The physical properties of inks W1 to W6 obtained in Examples 1 to 5 and Comparative Example 1 were measured as follows, including the volume average particle size (D50) and dynamic surface tension. The results are shown in Table 2 below.

[0144] -Volume average particle size- The volume average particle diameters of inks W1 to W6 obtained in Examples 1 to 5 and Comparative Example 1 were measured as D50 values ​​by dynamic light scattering using a particle size distribution analyzer (Nanotrac WAVE II, manufactured by Microtrackbell).

[0145] -Dynamic surface tension- The dynamic surface tensions of inks W1 to W6 obtained in Examples 1 to 5 and Comparative Example 1 when the bubble lifetime was 15 msec according to the maximum bubble pressure method were measured at 25°C using a portable dynamic surface tensiometer (SITA Science line t100, manufactured by Eiko Seiki Co., Ltd.).

[0146] [Table 2]

[0147] <Evaluation of Dispersion Stability of White Pigment Ink Composition> Using a Turbiscan Lab (manufactured by Sanyo Trading Co., Ltd.), inks W1 to W6 obtained in Examples 1 to 5 and Comparative Example 1 were each filled to 4 cm in a 6 cm high sample container. The backscattered light (BS) intensity at a point 1 cm from the liquid surface at 25°C was measured daily for 7 days, and the △BS value [(%) variation in backscattered light intensity from the initial value] was evaluated. The closer the △BS value is to 0%, the less likely sedimentation of the white pigment occurs, indicating excellent dispersion stability. The results are shown in Table 5 below.

[0148] [Preparation Example 3: Preparation of Dispersion 3 for Color Ink] A solution was obtained by dissolving 6.0 parts of the polymer dispersant A obtained in Preparation Example 1 in 2-butanone (20 parts). A solution prepared by dissolving 0.47 parts of sodium hydroxide in 51.5 parts of water was added to this solution, and the mixture was stirred for 1 hour to obtain an emulsion. 21 parts of CI Pigment Yellow 155 was added to the resulting solution, and the mixture was dispersed in a sand grinder at 1500 rpm for 15 hours under water cooling to obtain a solution. The resulting solution was diluted with ion-exchanged water, and the dispersion beads were filtered off to obtain a filtrate. This filtration was performed using two sheets of glass filter paper manufactured by Advantec Co., Ltd., with GA100 on top and GC50 on the bottom. The 2-butanone and a portion of the water in the resulting filtrate were distilled off under reduced pressure using an evaporator to obtain Dispersion 3 with a pigment solids content of 12%. [Preparation Example 4: Preparation of Dispersion 4 for Color Ink] Dispersion liquid 4 having a pigment solids content of 12% was obtained in the same manner as in Preparation Example 3, except that CI Pigment Red 122 was used instead of CI Pigment Yellow 155 as the pigment. [Preparation Example 5: Preparation of Dispersion 5 for Color Ink] Dispersion 5 having a pigment solids content of 12% was obtained in the same manner as in Preparation Example 3, except that CI Pigment Blue 15:4 was used instead of CI Pigment Yellow 155 as the pigment. [Preparation Example 6: Preparation of Dispersion 6 for Color Ink] Dispersion Liquid 6 having a pigment solids content of 12% was obtained in the same manner as in Preparation Example 3, except that carbon black was used instead of CI Pigment Yellow 155 as the pigment.

[0149] [Preparation Examples 7 to 10: Preparation of Color Inks] The components listed in Table 3 below were mixed and thoroughly stirred, then filtered through a membrane filter with a pore size of 3 μm and degassed using a vacuum pump to obtain inks Y1, M1, C1, and K1 to be used in evaluation tests. Note that the numerical values ​​for each component are in parts, and the amount of water added was adjusted so that the total was 100 parts.

[0150] The abbreviations in Table 3 below have the following meanings: W-5130: Takelac W-5130 (Mitsui Chemicals, active ingredient content 35%) Bayhydur BL2867: Blocked isocyanate group-containing compound (manufactured by Sumika Covestro Urethane Co., Ltd., active ingredient content 38%) SF420: Surfynol 420 (surfactant, manufactured by Nissin Chemical Industry Co., Ltd.) TEA: Triethanolamine manufactured by Junsei Chemical Co., Ltd. GXL(S): PROXEL GXL(S) (preservative, manufactured by Lonza Corporation)

[0151] [Table 3]

[0152] Preparation Example 11: Preparation of Pretreatment Solution 1 Pretreatment solution 1 was obtained by mixing the components shown in Table 4 below.

[0153] The abbreviations in Table 4 below have the following meanings. The numerical values ​​in Table 4 are in parts. DK6850: Epihalohydrin-modified polyamine resin (Seiko PMC Corporation, weight-average molecular weight: 1703) Epocross WS-700: Oxazoline group-containing compound (Nippon Shokubai Co., Ltd., oxazoline group-containing polymer, solid content 25%) Movinyl 6963: (meth)acrylic resin copolymer (Japan Coating Resin Co., Ltd., anionic styrene / acrylic resin emulsion, solid content 45% by mass)

[0154] [Table 4]

[0155] [Recording method] [Pretreatment process] Using a commercially available spray bottle (Mitsugiron Co., Ltd., Fine Spray), the pretreatment liquid 1 obtained above was applied at a coating amount of 0.025 g / cm. 2 Each solution was applied to an A4 size polyester fabric (dry T-shirt, black 00300-ACT (Glimmer)). Then, a tabletop automatic press (AF-65TEN manufactured by Asahi Textile Machinery Co., Ltd.) was used to apply the solution at a pressure of 1.0 N / cm. 2 The fabric was then dried by heating at 130°C for 60 seconds to obtain a pretreated fabric.

[0156] [Recording process] Each of the inks W1 to W6 was filled into an industrial inkjet evaluation device (extended coating device EV2500: manufactured by Ricoh Co., Ltd.), and each of the inks W1 to W6 was applied to a part of the surface area of ​​the pretreated fabric obtained above in an amount of 17 mg / cm under the conditions of an ink droplet weight of 29 pL / dot, a head temperature of 25°C, a resolution of 600 × 1200 dpi, and two-overprinting. 2 After each of the inks W1 to W6 was applied, the ink was dried by heating at 130°C for 30 seconds using a tabletop automatic press (AF-65TEN manufactured by Asahi Textile Machinery Co., Ltd.) without contact, and then dried under a pressure of 1.0 N / cm. 2 The resulting product was dried by heating at 130°C for 30 seconds three times to obtain a white printed product.

[0157] [Whiteness] The L of the printed surface of the printed product obtained as above* The color values ​​were measured using a spectrophotometer (X-Rite Ci62, manufactured by X-Rite) under the measurement conditions of a light source of D65 and a viewing angle of 2°, in CIE / L. * a * b * In the color system, L * The measurement was carried out five times for each printed item, and the average value was used as the measurement result and evaluated according to the following evaluation criteria. The evaluation results are shown in Table 5. (Evaluation criteria) A:L * Value is 85 or higher B:L * Value is between 80 and 85 C:L * Value is between 75 and 80 D:L * Value less than 75

[0158] [Preparation of a printed item overprinted with Ink M1] Using an industrial inkjet evaluation device (extended coating device EV2500: manufactured by Ricoh Co., Ltd.), ink droplet weight was 29 pL / dot, head temperature was 25°C, resolution was 600 × 1200 dpi, and two-overprinting was performed on a portion of the surface area of ​​the pretreated fabric obtained above. Each of the inks W1 to W6 was applied to a portion of the surface area of ​​the pretreated fabric obtained above in an amount of 17 mg / cm. 2 After that, color ink M1 was ejected under the conditions of an ink droplet weight of 29 pL / dot, a head temperature of 25°C, and a resolution of 600 x 1200 dpi to form a color solid pattern image on the white solid pattern image. After that, a tabletop automatic press (AF-65TEN manufactured by Asahi Textile Machinery Co., Ltd.) was used to perform non-contact heat drying at 130°C for 30 seconds, and then the pressure was 1.0 N / cm. 2 The white ink was then dried by heating at 130°C for 30 seconds three times, to obtain each printed item in which ink M1 was printed on top of the white ink.

[0159] [Rubbing durability test] Each of the printed textiles obtained as described above was subjected to a color fastness test against rubbing using a Type II (Gakushin-type) testing machine in accordance with the method specified in JIS L 0849. Dry rubbing was tested in accordance with the dry test specified in JIS L 0849, and wet rubbing was tested in accordance with the wet test specified in JIS L 0849, and the results were evaluated using the stain gray scale. The test results are shown in Table 5.

[0160] [Evaluation of stickiness] The texture of each printed textile obtained as described above was evaluated by a sensory test. Specifically, an examiner touched the printed surface of the obtained printed textile with his / her index finger and performed a sensory evaluation of the feel according to the following criteria to evaluate the texture. The evaluation results are shown in Table 5. A rating of B or higher indicates no practical problems. A: There is absolutely no sticky feeling on the printed item. B: The printed item has a slightly sticky feel. C: The printed item has a noticeable sticky feel.

[0161] [Table 5]

[0162] [Preparation of a printed item with overprinting of color inks Y1, C1, and K1] White inks W3 and W6 were applied to a portion of the surface area of ​​the pretreated fabric obtained above at a deposition amount of 17 mg / cm using an industrial inkjet evaluation device (extended coating device EV2500: manufactured by Ricoh Co., Ltd.) under the conditions of an ink droplet weight of 29 pL / dot, a head temperature of 25°C, a resolution of 600 × 1200 dpi, and two-overprinting. 2 After forming a white solid pattern image, color inks Y1, C1, and K1 were ejected under the conditions of an ink droplet weight of 29 pL / dot, a head temperature of 25°C, and a resolution of 600 x 1200 dpi to form a color solid pattern image on the white solid pattern image. After that, a tabletop automatic press (AF-65TEN manufactured by Asahi Textile Machinery Co., Ltd.) was used to perform non-contact heat drying at 130°C for 30 seconds, and then the pressure was 1.0 N / cm.2 The white ink was then dried by heating at 130°C for 30 seconds three times, to obtain printed products in which the color inks Y1, C1, and K1 were printed on top of each other.

[0163] The rub fastness test and stickiness evaluation were carried out in the same manner as for each of the above-mentioned printed products overprinted with ink M1. The test results are shown in Table 6.

[0164] [Table 6]

[0165] As is clear from the results in Table 5 above, the white ink compositions of Examples 1 to 5 were less susceptible to settling of the white pigment and had excellent dispersion stability, and textile prints using the white ink compositions had high whiteness and, when overprinted with color inks, were good in rub fastness and stickiness (hand feel).The results in Table 6 also show that textile prints using the ink sets of Examples 6 to 8 had better rub fastness and stickiness (hand feel) than textile prints using the ink sets of Comparative Examples 2 to 4. [Industrial Applicability]

[0166] The white pigment ink composition for inkjet textile printing of the present invention has good dispersion stability and can produce excellent printed textiles having high whiteness and hiding power. Furthermore, the printed textiles produced using the ink set of the present invention have excellent rub fastness and stickiness (hand feel), making the white pigment ink composition for inkjet textile printing extremely useful.

Claims

1. A white pigment ink composition for inkjet textile printing, comprising: a white pigment; a polymer dispersant; a urethane resin; a water-soluble organic solvent; and water, wherein the white pigment has a volume average particle diameter (D50) of 200 to 270 nm; and the water-soluble organic solvent comprises glycerin and a polyhydric alcohol having a boiling point of 215°C or less.

2. 2. The white pigment ink composition for ink-jet textile printing according to claim 1, wherein the polymer dispersant is a polymer constituted of at least two types of monomers selected from the group consisting of monomer A, monomer B, and monomer C represented by the following formula (1): Monomer A: A monomer represented by the following formula (1), in which R is a hydrogen atom. Monomer B: A monomer represented by the following formula (1), in which R is a C1-C6 alkyl group. Monomer C: A monomer represented by the following formula (1), in which R is an aryl group or an aryl C1-C4 alkyl group. 【Chemical 1】

3. 3. The white pigment ink composition for ink-jet textile printing according to claim 1, wherein the polymer dispersant has a weight average molecular weight of 10,000 to 40,000.

4. The white pigment ink composition for ink-jet textile printing according to claim 1 or 2, wherein the urethane resin comprises two types of resins: a polyester-type urethane resin and a polycarbonate-type urethane resin.

5. 3. The white pigment ink composition for ink-jet textile printing according to claim 1, which has a static surface tension of 30 to 40 mN / m and a viscosity of 3 to 20 mPa·s at 25°C.

6. 3. An ink set comprising: the white pigment ink composition for inkjet textile printing according to claim 1; and one or more color ink compositions for inkjet textile printing, each containing a pigment, a block polymer type resin dispersant, a urethane resin, a crosslinking agent, a water-soluble organic solvent, a surfactant, and water.

7. 7. The ink set according to claim 6, wherein the block polymer type resin dispersant has a weight average molecular weight of 10,000 to 30,000.

8. The ink set according to claim 6, wherein the crosslinking agent is a blocked isocyanate group-containing compound.

9. The ink set according to claim 6, wherein the urethane resin according to claim 6 comprises two types of resins: a polyester type urethane resin and a polycarbonate type urethane resin.

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