Ink composition and printing method

Abstract

To provide an ink, and an ink set which can color various kinds of fabrics in inkjet printing and which can produce an image excellent in color development, fastness (light resistance, friction resistance, and washing resistance), ink temporal stability and inkjet discharge property, and an inkjet printing method using the ink.SOLUTION: An aqueous pigment printing ink composition contains a pigment, a block polymer type resin dispersant, an urethane resin, a crosslinking agent, a water-soluble organic solvent, a surface active agent and water, wherein the pigment is C.I. pigment yellow 155 and C.I. pigment yellow 74, and a mass ratio of the C.I. pigment yellow 155 to the C.I. pigment yellow 74 is within a range of 85:15 to 40:60.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a water-based pigment textile printing ink composition for use in inkjet textile printing, which contains a specific pigment, a block polymer type resin dispersant, a urethane resin, a crosslinking agent, a water-soluble organic solvent, a surfactant, and water, and further relates to an inkjet textile printing method and a dyeing method using the ink composition. [Background technology]

[0002] As information becomes increasingly digitalized, inkjet recording has become widespread as a printing method for both offices and homes. In recent years, inkjet recording has also been widely applied to commercial printing, textile printing, and other fields. As the applications of inkjet recording expand, the colorants used in inkjet inks have shifted from conventional water-soluble dyes such as acid dyes and reactive dyes to water-insoluble colorants, i.e., various colorants such as disperse dyes and pigments, depending on the application.

[0003] An example of an inkjet ink using a pigment is the ink disclosed in Patent Document 1. This is a dispersion ink composition using a polymer dispersant. Patent Document 2 discloses an ink composition using a self-dispersing pigment. In recent years, a method has also become known in which a resin is mixed into the ink and then cured and fixed to the recording material by heat treatment, as disclosed in Patent Documents 3 and 4, for example.

[0004] Inkjet printing using water-insoluble colorants has been problematic in that it can cause bleeding and reduced color development on the fabric. To address these issues, it has been proposed to pretreat the fabric. For example, Patent Documents 5 and 6 listed below propose such treatment solutions.

[0005] On the other hand, when pretreatment is performed, there are problems such as "traces" of the pretreatment liquid remaining on the fibers in the areas where the pretreatment liquid was applied, and discoloration such as yellowing over time. Furthermore, variations in the pretreatment process are likely to cause density unevenness in printed matter, which is also a problem. Given the above, there is a strong demand for inkjet inks that can achieve high color development and fastness (lightfastness, abrasion resistance, washability, etc.) even without pretreatment. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 3534395 [Patent Document 2] Patent No. 4016483 [Patent Document 3] Japanese Patent Application Laid-Open No. 2011-246633 [Patent Document 4] Japanese Patent Application Publication No. 9-143407 [Patent Document 5] Japanese Patent Application Publication No. 07-119047 [Patent Document 6] Japanese Patent Application Laid-Open No. 2000-226781 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention aims to provide an ink, an ink set, and an inkjet printing method using the ink, which are capable of coloring various types of fabrics and which have excellent color development properties, fastness (light resistance, abrasion resistance, and washing resistance) of the obtained images, stability over time of the ink, and inkjet dischargeability. [Means for solving the problem]

[0008] The present inventors have conducted intensive research to solve the above-mentioned problems, and as a result have found that the above-mentioned problems can be solved by a water-based pigment printing 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, wherein the pigments are CI Pigment Yellow 155 and CI Pigment Yellow 74, and the mass ratio of CI Pigment Yellow 155 to CI Pigment Yellow 74 is in the range of 85:15 to 40:60, thereby completing the present invention.

[0009] That is, the present invention relates to the following 1) to 11). 1) A water-based pigment printing 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, wherein the pigments are CI Pigment Yellow 155 and CI Pigment Yellow 74, and the mass ratio of CI Pigment Yellow 155 to CI Pigment Yellow 74 is in the range of 85:15 to 40:60. 2) 1) The water-based pigment textile printing ink composition according to 1), wherein the total content of the pigments is 3.0 to 7.0% based on the total mass of the ink. 3) 1) The water-based pigment textile printing ink composition according to 1) or 2), wherein the block polymer type resin dispersant has a weight average molecular weight of 10,000 to 40,000. 4) The water-based pigment textile printing ink composition according to any one of 1) to 3), wherein the crosslinking agent comprises a blocked isocyanate group-containing compound. 5) 4) The water-based pigment textile printing ink composition according to any one of 1) to 4), wherein the dissociation temperature of the blocked isocyanate group-containing compound is 120° C. or higher. 6) The water-based pigment textile printing ink composition according to any one of 1) to 5), wherein the urethane resin comprises two types of resins: a polyester-type urethane resin and a polycarbonate-type urethane resin. 7) 6) The water-based pigment textile printing ink composition according to any one of 1) to 6), which has a surface tension of 30 to 40 mN / m and a viscosity of 2 to 20 mPa·s at 25°C. 8) An ink set for inkjet textile printing, comprising a magenta ink composition, a cyan ink composition, a yellow ink composition, and a black ink composition, wherein the yellow ink composition is the water-based pigment textile printing ink composition according to any one of 1) to 7). 9) An inkjet textile printing method in which droplets of the water-based pigment textile printing ink composition according to any one of 1) to 7) are ejected in response to a recording signal and deposited on a recording material, thereby carrying out textile printing. 10) 9) The inkjet printing method according to 9), wherein the recording material is a fiber selected from the group consisting of polyester, cellulose, polyamide, and natural fiber, a blended fiber containing these fibers, or a fabric containing these fibers. 11) An inkjet dyeing method in which a pigment contained in an ink composition that has been applied to a recording material by the inkjet printing method according to 9) or 10) is dyed onto the recording material by steaming or baking. [Effects of the Invention]

[0010] The present invention can provide a water-based pigment textile printing ink composition and ink set for use in inkjet textile printing, which are excellent in color development, fastness (light resistance, abrasion resistance, and washing resistance), ink stability over time, and inkjet ejection properties, as well as an inkjet textile printing method and a dyeing method using the same. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described in detail below. In this specification, the "water-based pigment textile printing ink composition" may be abbreviated as "ink." Furthermore, unless otherwise specified, in this specification, including the examples, "%" and "parts" are all expressed on a mass basis. Also, "CI Pigment Yellow" is sometimes abbreviated as "PY."

[0012] [Water-based pigment textile printing ink composition] The water-based pigment textile printing ink composition contains at least two pigments, PY155 and PY74, and further contains at least a block polymer type resin dispersant, a urethane resin, a crosslinking agent, a water-soluble organic solvent, a surfactant, and water.

[0013] The mass ratio of PY155 to PY74 in the total mass of the pigments contained in the ink composition is 85:15 to 40:60, preferably 83:17 to 50:50, more preferably 81:19 to 60:40, and particularly preferably 80:20 to 65:35. By setting the mass ratio of PY155 to PY74 to 85:15 to 40:60, a recorded image with a good balance of color development, saturation, and lightfastness can be obtained.

[0014] The total pigment content of the ink composition is usually 3.0 to 7.0%, preferably 3.5 to 6.5%, more preferably 3.8 to 6.0%, and even more preferably 4.0 to 5.5%. A content of 3.0% or more improves the color development of the recorded image, while a content of 7.0% or less improves the ejection properties.

[0015] [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.

[0016] The block polymer type resin dispersant may be an alternating copolymer of monomers, a block copolymer, or a graft copolymer, and may be synthesized or commercially available.

[0017] Examples of block polymer resin dispersants obtained by synthesis include the AB block polymers disclosed in WO 2013 / 115071 and WO 2022 / 025166.

[0018] 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.

[0019] 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 mass%, preferably 0.5 to 5 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), 9171 (amine value: 28 mg KOH / g), BASF's DIspex Uitra PX 4575 (amine value: 32 mg KOH / g), 4585 (amine value: 20 mg KOH / g); AFCONA's AFCONA-4597 (acid value: 10 mg KOH / g, amine value: 13 mg KOH / g), 4598 (acid value: 11 mg KOH / g); and the like.

[0020] 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.

[0021] 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 ink composition may decrease, and if the acid value is too large, the color development may decrease.

[0022] 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.

[0023] 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.

[0024] 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%.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] These neutralizing agents may be used alone or in combination of two or more.

[0030] [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.

[0031] 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.

[0032] 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. WS-4000, WS-5000, WS-5030, WS-5100, WS-5130, W-6061, W-6110, WS-5984 (all trade names manufactured by Mitsui Chemicals, Inc.); Among these, examples of polyester-type urethane resins include Superflex 210, 500M, and 740; Takelac WS-4000, WS-5000, WS-5030, WS-5130, and WS-5984; and examples of polycarbonate-type urethane resins include Permarin UA-310 and 3945; U-coat UX-320; Hydran WLS-210, 213, and 250; and Takelac W-6110.

[0033] 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.

[0034] [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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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 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 trade names, manufactured by Meisei Chemical Industry Co., Ltd.); and Elastron BN-69 and BN-7. 7, BN-27, BN-11 (all manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade names); Takenate WB-700, WB-770, WB-920 (all manufactured by Mitsui Chemicals, Inc., trade names); Duranate MF-K60B, SBN-70D, MF-B60B, MF-B90B, 17B-60P, TPA-B80B, TPA-B80E, E402-B80B (all manufactured by Asahi Kasei Corporation, trade names); Fixer N (all manufactured by Matsui Dye Chemical Research Institute Co., Ltd.); and Bayhydur BL2867 (manufactured by Sumika Covestro Urethane Co., Ltd.).

[0040] 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.

[0041] 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).

[0042] 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.

[0043] 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.).

[0044] 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.

[0045] 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.).

[0046] 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.

[0047] [Water-soluble organic solvent] Examples of the water-soluble organic solvent 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.

[0048] Examples of the polyhydric alcohols 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, 1,3-pentanediol, 1,4-pentanediol, 1,4-pentanediol, 1,5 ... Examples of suitable hexanediol include hexanediol, 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.

[0049] 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.

[0050] Examples of the polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

[0051] 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.

[0052] Examples of the amides include formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, and 3-butoxy-N,N-dimethylpropionamide.

[0053] 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.

[0054] From the viewpoint of the drying property and ejection stability of the ink composition, the water-soluble organic solvent preferably contains a polyhydric alcohol having a boiling point of 250°C or higher and a polyhydric alcohol having a boiling point of 210°C or lower, and the content of the polyhydric alcohol having a boiling point of 250°C or higher is preferably 27% or lower, and more preferably 25% or lower, of the total amount of ink.

[0055] Examples of the polyhydric alcohol having a boiling point of 250° C. or higher include glycerin (boiling point: 290° C.).

[0056] Examples of the polyhydric alcohol having a boiling point of 210°C or less include isoprene glycol (boiling point: 203°C).

[0057] The content of the water-soluble organic solvent is preferably 10 to 50% by mass, more preferably 14 to 45% by mass, and even more preferably 16 to 35% by mass, relative to the total mass (100% by mass) of the ink composition. When the content of the water-soluble organic solvent is within the above range, there is a tendency for the ink composition to be excellent in terms of reducing ejection defects.

[0058] [Surfactants] The surfactant 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).

[0059] Among these, nonionic surfactants are preferred from the viewpoint of storage stability, foaming property, and defoaming property of the ink.

[0060] The content of the surfactant is usually 0.05 to 5%, preferably 0.05 to 3%, more preferably 0.05 to 1%, and even more preferably 0.1 to 0.5%, based on the total mass of the ink composition. By setting the content in this range, the washing fastness and abrasion resistance of the printed fabric tend to be excellent. Furthermore, the storage stability of the ink composition also tends to be excellent.

[0061] [water] The water-based pigment textile printing ink composition contains water. The water may be pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, or distilled water, or ultrapure water. The water content is not particularly limited and may be determined as needed. However, to adjust the viscosity of the ink composition to a suitable range, the water content is preferably 20 to 80% by mass relative to the total mass (100% by mass) of the ink composition. While not limited thereto, the water content is preferably 40 to 80% by mass, more preferably 45 to 75% by mass, and even more preferably 50 to 70% by mass.

[0062] The water-based pigment textile printing ink composition may further contain additives.

[0063] Examples of the additives include waxes, preservatives, chelating agents, rust inhibitors, water-soluble ultraviolet absorbers, water-soluble polymer compounds, viscosity adjusters, dye dissolving agents, anti-fading agents, antioxidants, and anti-foaming agents.

[0064] The wax may be either a natural wax or a synthetic wax. Examples of natural waxes include petroleum-based waxes such as paraffin wax and microcrystalline wax; plant-based waxes such as carnauba wax, candelilla wax, and rice wax; and animal-based waxes such as lanolin and beeswax. Examples of synthetic waxes include synthetic hydrocarbon waxes such as polyolefin wax and Fischer-Tropsch wax; silicone-based waxes; and modified waxes such as paraffin wax derivatives, montan wax derivatives, and microcrystalline wax derivatives. Among these, polyolefin waxes containing an olefin-based monomer as the main component are preferred. The above waxes may be used alone or in combination of two or more.

[0065] From the viewpoint of improving the storage stability of the ink, the melting point of the wax used in the present invention is 80°C or higher, preferably 100°C or higher, more preferably 105°C or higher, even more preferably 108°C or higher, and preferably 150°C or lower, more preferably 145°C or lower, even more preferably 140°C or lower.

[0066] Examples of the olefin monomer that is the main component of the polyolefin wax include linear olefins and cyclic olefins. Preferred are those primarily composed of linear olefins having 2 to 6 carbon atoms. Polyolefin waxes primarily composed of ethylene or propylene are more preferred, and polyethylene waxes primarily composed of ethylene are even more preferred. Here, "primarily composed of ethylene or propylene" means that the ethylene or propylene content of the wax is preferably 50% by mass or more, more preferably 65% ​​by mass or more, and even more preferably 80% by mass or more. Oxidized polyolefin waxes can be obtained by adjusting a high-molecular-weight polyolefin polymer to the desired molecular weight by thermal decomposition or the like while introducing oxygen atoms into the molecule, and are included in the category of polyolefin waxes. In other words, the polyolefin wax is preferably one or more selected from polyethylene wax, polypropylene wax, and oxidized polyethylene wax, and polyethylene wax is more preferred.

[0067] From the same viewpoint as above, the weight average molecular weight of the polyolefin wax is preferably 400 or more, more preferably 600 or more, and even more preferably 800 or more, and is preferably 10,000 or less, more preferably 8,000 or less, and even more preferably 6,000 or less.

[0068] Commercially available polyolefin waxes include Honeywell's product name "A-C8" (polyethylene wax), INNOSPEC's product name "VISCOWAX122" (polyethylene wax), Honeywell's product name "A-C400" (ethylene-vinyl acetate copolymer wax), INNOSPEC's product name "VISCOWAX334" (ethylene-vinyl acetate copolymer wax), INNOSPEC's product name "VISCOWAX343" (ethylene-vinyl acetate copolymer wax), Polyethylene wax emulsions manufactured by Toho Chemical Industry Co., Ltd. include E-4B, E103N, E-1000, E-5403B, E-6000, E-6314, E-6400, S-3121, S-3123, S-3125, and S-3148; polypropylene wax emulsions include Hi-Tec E-433N and Hi-Tec E-5060; polyethylene wax emulsions manufactured by Rohm and Haas Japan Co., Ltd. include Polyem 20 and Polyem 40J; and polyethylene wax emulsion Chemipearl W- manufactured by Mitsui Chemicals, Inc. 100, W-200, W-300, W-308, W-310, W-400, W-401, W-4005, W-410, W-500, WF-640, W-700, W-800, W-900, W-950 and W-4005, polyolefin resins described in JP 2003-201436 A, AQUACER 1550, 497, 500 series, 840, 1000 series, 2500, 2650, 3500, 8075 and 8976 manufactured by BYK-Chemie, S-32 manufactured by Sherlock Technology Inc. (USA), 3, S-363, S-368N5T, S-379, S-381, S-390C, S-394, S-395, S-395SD4, S-400, S-483, NEPUUNE-1, NEPUUNE-5031, NEPUUNE-968, NEPUUNE-5223N4, NEPUUNE-5331 and NEPUUNE-5918, carnauba wax emulsion WE-100 and carnauba wax emulsion WE-1-252 manufactured by Shin-Ei Sangyo Co., Ltd., wax emulsions manufactured by Nikko Fine Products Co., Ltd., and the like.

[0069] Examples of the preservative 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).

[0070] Specific examples of the chelating agent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, sodium uracildiacetate, and the like.

[0071] Examples of the rust inhibitor include acid sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

[0072] Examples of the water-soluble ultraviolet absorber include sulfonated benzophenone compounds, benzotriazole compounds, salicylic acid compounds, cinnamic acid compounds, and triazine compounds.

[0073] Examples of the water-soluble polymer compound include polyvinyl alcohol, cellulose derivatives, polyamines, and polyimines.

[0074] Examples of the viscosity modifier include water-soluble organic solvents and water-soluble polymer compounds, such as polyvinyl alcohol, cellulose derivatives, polyamines, and polyimines.

[0075] Examples of the dye dissolving agent include urea, ε-caprolactam, and ethylene carbonate.

[0076] The anti-fading agent is used for the purpose of improving the storage stability of images. As the anti-fading agent, 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.

[0077] The antioxidant may be, for example, a variety of organic and metal complex anti-fading agents, including hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, and heterocycles.

[0078] Specific examples of antifoaming agents include silicone-based, silica mineral oil-based, olefin-based, and acetylene-based agents. Commercially available antifoaming agents include Surfynol TMDF37, DF58, DF110D, DF220, MD-20, and Olfine TMSK-14, all manufactured by Shin-Etsu Chemical Co., Ltd. These antifoaming agents may be used alone or in combination of two or more. The amount of antifoaming agent added is preferably 0.01 to 5%, more preferably 0.03 to 3%, and even more preferably 0.05 to 1%. A content of 0.01% or more improves the antifoaming effect, while a content of 5% or less improves dispersion stability.

[0079] [Static surface tension of water-based pigment textile printing 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 38 mN / m, even more preferably 33 to 37 mN / m, and particularly preferably 34 to 36 mN / m, from the viewpoint of being able to exhibit sufficient wettability to various fabrics.

[0080] The static surface tension of the water-based pigment textile printing 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.

[0081] [Viscosity of Water-Based Pigment Textile Printing Ink Composition] The viscosity of the water-based pigment textile printing ink composition at 25° C. is preferably 2 to 20 mPa·s, and more preferably 3 to 18 mPa·s. An ink composition that satisfies the above viscosity range tends to exhibit good ejection response during high-speed printing.

[0082] The viscosity of the water-based pigment textile printing ink composition can be measured using, for example, an E-type viscometer (TV-22, manufactured by Toki Sangyo Co., Ltd.).

[0083] [pH of water-based pigment textile printing ink composition] The pH of the water-based pigment textile printing ink composition is adjusted to pH 7 to 11, and more preferably pH 8 to 10, for the purpose of improving storage stability and compatibility with inkjet printer components.

[0084] [Inkjet textile printing ink set] The above-mentioned aqueous pigment textile printing ink composition is preferably used as a yellow ink. The above-mentioned ink composition may be used alone, or, for the purpose of obtaining a full-color recorded image, it is preferably used as an inkjet textile printing ink set including, for example, a cyan ink composition, a magenta ink composition, and a black ink composition. In this case, the colorants contained in each of the cyan, magenta, and black ink compositions are not particularly limited, and any known pigment can be used. In addition to this four-color ink set, ink compositions such as violet, orange-brown, and green may also be optionally added to form an ink set of four or more colors in order to obtain a recorded image with higher resolution hues.

[0085] The pigments that may be contained in the ink compositions of each color for the purpose of obtaining a full-color recorded image are described below. Pigments are mainly inorganic pigments, organic pigments, extender pigments, etc., and any of these pigments may be used. These pigments may be used alone or in combination. The purpose of using pigments in combination is to adjust the hue. Examples of adjusting the hue include adding shade to the recorded image and widening the color gamut. Using multiple pigments in combination can also improve the storage stability of the ink composition, which may be a goal.

[0086] Specific examples of the organic pigments contained in the cyan, magenta, black, violet, orange-brown, and green ink compositions include cyan (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; magenta (red) pigments such as CI Pigment Red 5, 7, 12, 48, 48:1, 57, 88, 112, 122, 123, 146, 149, 150, 166, 168, 177, 178, 179, 184, 185, 202, 206, 207, 254, 255, 257, 260, 264, and 272; black pigments such as CI Pigment Black 1; and CI Pigment Violet. violet pigments such as CI Pigment Orange 13, 16, 68, 69, 71, 73; and green pigments such as CI Pigment Green 7, 36, 54. Of these, the cyan (blue) pigment contained in the cyan ink composition is preferably at least one selected from CI Pigment Blue 15:3 and 15:4, and the magenta (red) pigment contained in the magenta ink composition is preferably at least one selected from CI Pigment Red 122 and 150. Examples of inorganic pigments include carbon black, metal oxides, metal hydroxides, metal sulfides, metal ferrocyanides, and metal chlorides. Carbon black is particularly preferred as a pigment contained in the black ink composition. Examples of carbon black include thermal black, acetylene black, oil furnace black, gas furnace black, lamp black, gas black, and channel black. Of these, gas furnace black, lamp black, acetylene black, and channel black are preferred.

[0087] The carbon black is readily available as a commercial product. Specific examples 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); and Color Black. FW1, Color Black FW2, Color Black FW18, Color Black FW200, Color Black FW285, 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 (manufactured by Degussa); MA7, MA8, MA100, MA600, MCF-88, No.25, No.33, No.40, No.47, No.52, No.900, No.2300 (manufactured by Mitsubishi Chemical); Nerox 305, Nerox 505, Nerox 510, Nerox 605, Nerox 600 (all manufactured by Orion Engineered Carbons);

[0088] Examples of organic pigments include soluble azo pigments, insoluble azo pigments, insoluble diazo pigments, condensed azo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, dioxazine pigments, perylene pigments, perinone pigments, thioindigo pigments, anthraquinone pigments, and quinophthalone pigments.

[0089] Examples of extender pigments include silica, calcium carbonate, talc, clay, barium sulfate, white carbon, etc. These extender pigments are not used alone, but are usually used in combination with inorganic or organic pigments.

[0090] The total content of pigments in the total mass of each of the cyan, magenta, black, and other ink compositions is usually 1 to 20%, preferably 1 to 10%, and more preferably 2 to 7%.

[0091] From the viewpoint of safety and ejection properties, it is preferable to use the above pigments that contain as little as possible, for example, mutagenic synthetic raw materials, various metal salts such as calcium, other organic impurities, by-products produced during synthesis, etc.

[0092] The components of the water-based pigment textile printing ink compositions other than the yellow ink that make up the ink set of this embodiment are as described above.

[0093] [Method for preparing water-based ink composition] The water-based pigment textile printing ink composition can be prepared, for example, by preparing an aqueous dispersion containing the above components and, if necessary, further adding an additive such as a water-soluble organic solvent.

[0094] The ink composition may be subjected to microfiltration using a membrane filter or the like. In particular, when the ink composition is used as an inkjet printing ink, microfiltration is preferably performed to prevent nozzle clogging, etc. The pore size of the filter used for microfiltration is usually 0.1 to 1 μm, and preferably 0.1 to 0.8 μm.

[0095] The ink composition according to this embodiment can be used in various fields and is suitable for use as a water-based writing ink, a water-based printing ink, an information recording ink, textile printing, etc. The ink composition according to this embodiment is particularly preferably used as an inkjet textile printing ink.

[0096] The inkjet printing method is a method of printing by ejecting droplets of the ink composition in response to a recording signal and depositing them on a recording material. There are no particular restrictions on the ink nozzles and the like of the inkjet printer used for printing, and they can be appropriately selected depending on the purpose.

[0097] The above-mentioned textile printing method can be any of known methods, such as a charge control method that uses electrostatic attraction to eject ink; a drop-on-demand method (pressure pulse method) that uses the vibration pressure of a piezoelectric element; an acoustic inkjet method that converts an electric signal into an acoustic beam and irradiates the ink, and then uses the radiation pressure to eject the ink; and a thermal inkjet method that heats the ink to form bubbles and uses the resulting pressure.

[0098] The recording material used in the inkjet printing method includes 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, cotton wool, 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 made of a single material or blends of these materials. These fibers may also be provided with an ink-receiving layer (bleed-preventing layer). Methods for forming an ink-receiving layer on such fibers are well-known and commonly used techniques, and fibers with ink-receiving layers are commercially available. Furthermore, an ink-receiving layer can be provided on the fiber by appropriately selecting constituent components, forming methods, and the like from well-known and commonly used techniques. The ink-receiving layer is not particularly limited as long as it has the required function.

[0099] The inkjet dyeing method is a method in which the pigment contained in the ink composition, which has been applied to a recording material using the inkjet printing method, is fixed to the recording material by steaming or baking. Steaming treatment, for example, can be performed using a high-temperature steamer at a temperature of typically 80 to 250°C, preferably 170 to 180°C, for typically 10 seconds to 30 minutes, preferably about 10 minutes (wet heat fixation). Baking (thermosol) treatment can be performed at a temperature of typically 80 to 250°C, preferably 170 to 210°C, for typically 10 seconds to 30 minutes, preferably about 60 to 180 seconds (dry heat fixation). In this way, a dyed product dyed by the inkjet dyeing method is obtained. The dyed product refers to a recording material dyed by the inkjet dyeing method.

[0100] To print on textiles using the inkjet printing method, for example, a container containing the ink composition is set at a predetermined position in an inkjet printer for textile printing that can transport fabric, and printing is performed on a recording material using the inkjet printing method. The inkjet printing method can perform full-color printing using the ink set.

[0101]

[0033] According to the ink composition of this embodiment, it is possible to provide an ink composition, particularly a yellow ink composition for use in inkjet printing, that has improved color development, lightfastness, and ink storage stability overall. Furthermore, an ink set and an inkjet printing method that use the ink composition of the present invention as a yellow ink composition also have an excellent balance of color fading with ink compositions of other colors other than the yellow ink composition, and can improve deterioration of dyed products due to aging. [Example]

[0102] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Note that the ink compositions in the examples are included in the above-mentioned water-based pigment textile printing ink composition. In addition, the preparation of each ink composition was carried out under stirring unless otherwise specified. Furthermore, the "water" used in the examples is ion-exchanged water.

[0103] [Preparation Example 1]: Preparation of Dispersion 1. Block copolymer A of Synthesis Example 3 was obtained by reproducing Synthesis Example 3 of WO 2013 / 115071. The obtained block copolymer A (6 parts) was added to 2-butanone (30 parts) to prepare a solution. A solution of sodium hydroxide (0.44 g) in ion-exchanged water (41 parts) was added to this solution and stirred for 1 hour to prepare an emulsion. CI Pigment Yellow 155 (20 parts) and dispersion beads were added to this emulsion, and the mixture was dispersed using a sand grinder (1500 rpm, 15 hours) to obtain a liquid. 100 parts of ion-exchanged water was added dropwise to the obtained liquid, and the dispersion beads were filtered out to obtain a filtrate. 2-butanone and a portion of the water were removed from the obtained filtrate under reduced pressure using an evaporator to obtain a dispersion with a colorant content of 12.0% (Dispersion 1).

[0104] [Preparation Example 2]: Preparation of Dispersion 2. A dispersion having a pigment content of 12.0% was obtained as "Dispersion 2" in the same manner as in "Preparation Example 1" above, except that CI Pigment Yellow 74 (20 parts) was used instead of CI Pigment Yellow 155 (20 parts).

[0105] [Examples 1 to 5 and Comparative Examples 1 to 5]: Preparation of inks. The components shown in Table 2 below were mixed, stirred for approximately 1 hour, and then filtered through a 3 μm membrane filter to obtain ink compositions of the examples and comparative examples. The abbreviations in Table 2 below have the following meanings: WLS-210: Hydran WLS-210 (DIC, active ingredient content 35%) W-6110: Takelac W-6110 (Mitsui Chemicals, active ingredient content 32%) 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%) GL: Glycerin SF420: Surfynol 420 TEA: Triethanolamine GXL(S): PROXEL GXL(S)

[0106] [Table 1]

[0107] [Preparation of fibers for evaluation] The ink compositions of Examples 1 to 5 and Comparative Examples 1 to 5 were ejected using an industrial inkjet evaluation device (extended coating device EV2500, manufactured by Ricoh Co., Ltd.) to inkjet record a yellow solid pattern image onto a white cotton fabric (a white T-shirt, 00085-CVT heavyweight T-shirt, manufactured by PrintStar). The head temperature was 25°C and the printing was performed at a resolution of 600 x 1200 dpi. The cotton fabric to which the ink composition had been attached was then heated in a heat press at 170°C for 1 minute to obtain printed materials for evaluation. The prints for evaluation obtained as described above were subjected to the following evaluation tests. The evaluation results of each test are shown in Table 2.

[0108] [Evaluation of color development] The color development was evaluated by measuring the Dy value of the printed material for evaluation. The Dy value was measured using an eXact colorimeter manufactured by X-Rite. The color measurement conditions were an observation light source of D65, an observation field of view of 2°, and density Status E. The color was measured five times for each evaluation fiber, and the average value was used as the measurement result. A higher Dy value is preferable because it indicates higher color development. The Dy value was rounded to two decimal places. The results are shown in Table 2 below.

[0109] [Rubbing durability test] Each of the prints for evaluation 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 according to the dry test specified in JIS L 0849, and wet rubbing was tested according to the wet test specified in JIS L 0849, and the results were evaluated using a staining gray scale. The test results are shown in Table 2 below.

[0110] [Washing fastness test] Each of the prints for evaluation obtained as described above was subjected to the American Association of Textile Chemists and Colorists (AATCC) 61 2A standard three times, and the degree of discoloration of the prints was judged according to the discoloration gray scale of JIS L0804:2004. The evaluation results are shown in Table 2. [Storage stability test] The viscosity was measured by the method described below, and the rate of change between the measured value immediately after preparation and the measured value after storage at 60°C for 7 days was calculated using the formula below, and each was evaluated according to the following four-level criteria. The smaller the discrepancy between the measured values ​​immediately after preparation and after 7 days of storage, the better the stability, indicating excellent storage stability. The results are shown in Table 2 below. Viscosity change rate = (measured value after storage - measured value immediately after preparation) / (measured value immediately after preparation) x 100% A: Change rate is less than ±5% B: Change rate is ±5% or more and less than ±8% C: Change rate is ±8% or more and less than ±15% D: Change rate is ±15% or more and less than ±20%

[0111] [Table 2]

[0112] A lightfastness test was carried out on the printed matter printed using the inks of Examples 1 to 5 obtained as described above.

[0113] [Lightfastness test] Each of the printed materials obtained using the inks of Examples 1 to 5 was left for 48 hours under conditions of 100,000 lux illuminance, 60% RH humidity, and 24°C temperature using a Low Temperature Xenon Weatherometer XL75 manufactured by Suga Test Instruments Co., Ltd. After the test, the degree of discoloration at the point of each printed material irradiated with the xenon lamp was judged using the JIS Discoloration Blue Scale. A higher rating indicates a lower degree of discoloration and a better result. The test results are shown in Table 3 below. The lightfastness of all of the printed materials printed using the inks of Examples 1 to 5 was grade 5 or higher, which was an excellent result.

[0114] [Table 3]

[0115] The results in Tables 2 and 3 above show that the water-based pigment textile printing ink compositions of the present invention have high color development and fastness (rubbing fastness, light fastness, and washing fastness), as well as high stability over time. [Industrial Applicability]

[0116] The water-based pigment textile printing ink composition of the present invention is extremely useful as an inkjet textile printing ink because it has excellent color development, fastness (rubbing fastness, light fastness, washing fastness) and stability over time.

Claims

1. 1. A water-based pigment printing ink composition comprising a pigment, a block polymer type resin dispersant, a urethane resin, a crosslinking agent, a water-soluble organic solvent, a surfactant, and water, wherein the pigments are C.I. Pigment Yellow 155 and C.I. Pigment Yellow 74, and the mass ratio of C.I. Pigment Yellow 155 to C.I. Pigment Yellow 74 is in the range of 85:15 to 40:

60.

2. 2. The water-based pigment textile printing ink composition according to claim 1, wherein the total content of the pigments is 3.0 to 7.0% by mass of the total ink.

3. 3. The water-based pigment textile printing ink composition according to claim 1, wherein the block polymer type resin dispersant has a weight average molecular weight of 10,000 to 40,000.

4. The water-based pigment textile printing ink composition according to claim 1 or 2, wherein the crosslinking agent comprises a blocked isocyanate group-containing compound.

5. 3. The water-based pigment textile printing ink composition according to claim 1, wherein the blocked isocyanate group-containing compound has a dissociation temperature of 120°C or higher.

6. The water-based pigment textile printing ink composition 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.

7. 3. The water-based pigment textile printing ink composition according to claim 1, which has a surface tension of 30 to 40 mN / m and a viscosity of 2 to 20 mPa·s at 25°C.

8. 3. An ink set for inkjet textile printing, comprising a magenta ink composition, a cyan ink composition, a yellow ink composition, and a black ink composition, wherein the yellow ink composition is the water-based pigment textile printing ink composition according to claim 1.

9. 3. An ink-jet textile printing method comprising ejecting droplets of the water-based pigment textile printing ink composition according to claim 1 in response to a recording signal and depositing the droplets on a recording material, thereby carrying out textile printing.

10. 10. The ink-jet printing method according to claim 9, wherein the recording material is a fiber selected from the group consisting of polyester, cellulose, polyamide, and natural fiber, a blended fiber containing these fibers, or a fabric containing these fibers.

11. An inkjet dyeing method, comprising the steps of: dyeing a recording material by steaming or baking the pigment contained in the ink composition that has been applied to the recording material by the inkjet printing method according to claim 9;

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