Water-based inkjet ink

Abstract

To solve the problem that aqueous ink for inkjet is difficult to secure dispersion stability.SOLUTION: An aqueous ink for inkjet contains a pigment aqueous dispersion, water and a water-soluble organic solvent, wherein the pigment aqueous dispersion contains a pigment dispersed with a polyurethane resin obtained by reaction of an active hydrogen atom-containing component (A) and an organic polyisocyanate component (B), the active hydrogen atom-containing component (A) contains a quaternary ammonium compound (a1), the organic polyisocyanate component (B) contains one or more selected from the group consisting of a linear or branched aliphatic polyisocyanate (b1), an alicyclic polyisocyanate (b2) and an aromatic polyisocyanate (b3), and the weight ratio of the quaternary ammonium compound (a1) is 12 wt.% or more based on the total weight of the active hydrogen atom-containing component (A) and the organic polyisocyanate component (B).SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to an ink for water-based inkjet printers. [Background technology]

[0002] Inkjet recording is a method of recording by ejecting small droplets of ink composition from a fine nozzle and adhering them to a recording medium. This method has the advantage of being able to record high-resolution and high-quality images at high speed using relatively inexpensive equipment. The recording media used in inkjet recording are expanding to absorbent media such as fabrics, and the range of recording media is becoming increasingly diverse.

[0003] For example, Patent Document 1 describes an aqueous dispersion of pigment (P) in which a pigment (P0) is coated with a polyurethane resin (U), wherein the polyurethane resin (U) is composed of one or more polyols (A) selected from the group consisting of polyester diols (A1), polycarbonate diols (A2), and polyether diols (A3), an aliphatic diisocyanate (B1) and / or an alicyclic diisocyanate (B2), and a diol (D) having a carboxyl group and / or a carboxylate anion group as essential constituent monomers, and the total content of carboxyl groups and carboxylate anion groups based on the weight of the polyurethane resin (U) is 4 to 80 mg / g. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2018-154829 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Conventionally, as shown in Patent Document 1, anionic dispersions have a negatively charged surface layer, which can lead to reduced color development due to penetration depending on the surface condition of the substrate during printing. To address this, a method using ammonium salt pigment dispersions with protons was considered, but ensuring dispersion stability was difficult with water-based inkjet inks. [Means for solving the problem]

[0006] The inventors diligently studied to solve the above problems. As a result, they were able to improve dispersion stability and color development by setting the content of the quaternary ammonium compound within a specific range.

[0007] In other words, the present invention is as follows. One embodiment of the present invention is an aqueous inkjet ink containing a pigment aqueous dispersion, water, and a water-soluble organic solvent, The aforementioned aqueous pigment dispersion contains a pigment dispersed in a polyurethane resin obtained by reacting an active hydrogen atom-containing component (A) with an organic polyisocyanate component (B). The active hydrogen atom-containing component (A) contains a quaternary ammonium compound (a1), The organic polyisocyanate component (B) contains one or more selected from the group consisting of linear or branched aliphatic polyisocyanates (b1), alicyclic polyisocyanates (b2), and aromatic polyisocyanates (b3). The present invention relates to an aqueous inkjet ink in which the weight percentage of the quaternary ammonium compound (a1) is 12% by weight or more, based on the total weight of the active hydrogen atom-containing component (A) and the organic polyisocyanate component (B).

[0008] In one embodiment of the present invention, it is preferable that the quaternary ammonium compound (a1) is a compound represented by the following general formula (1) and / or a compound represented by the following general formula (2). [ka] [In general formula (1), R1 and R 2 are each independently an alkyl group having 1 to 24 carbon atoms, and R 3 and R 4 are each independently an alkylene group having 1 to 20 carbon atoms or an oxyalkylene group having 2 to 20 carbon atoms, and X - is an anion.] [Chemical formula] [In General Formula (2), R 5 , R 6 and R 7 are each independently an alkyl group having 1 to 4 carbon atoms, and X - is an anion.]

[0009] In one embodiment of the present invention, it is preferable that the active hydrogen atom-containing component (A) contains one or more selected from the group consisting of polycarbonate polyol, polyester polyol, and polyether polyol.

[0010] In one embodiment of the present invention, it is preferable that the polycarbonate polyol is a crystalline polycarbonate polyol.

[0011] In one embodiment of the present invention, it is preferable that the water-soluble organic solvent contains a water-soluble organic solvent having a standard boiling point of 180 °C or higher.

[0012] In one embodiment of the present invention, it is preferable to further contain a surfactant.

[0013] In one embodiment of the present invention, it is preferable that the surfactant contains a nonionic surfactant. [Mode for Carrying Out the Invention]

[0014] Hereinafter, embodiments of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. However, the present invention is not limited thereto, and various modifications can be made without departing from the gist thereof.

[0015] The aqueous inkjet ink according to this embodiment (hereinafter also simply referred to as "ink") is an aqueous inkjet ink containing a pigment aqueous dispersion, water, and a water-soluble organic solvent, The aforementioned aqueous pigment dispersion contains a pigment dispersed in a polyurethane resin obtained by reacting an active hydrogen atom-containing component (A) with an organic polyisocyanate component (B). The active hydrogen atom-containing component (A) contains a quaternary ammonium compound (a1), The organic polyisocyanate component (B) contains one or more selected from the group consisting of linear or branched aliphatic polyisocyanates (b1), alicyclic polyisocyanates (b2), and aromatic polyisocyanates (b3). The weight percentage of the quaternary ammonium compound (a1) is 12% by weight or more, based on the total weight of the active hydrogen atom-containing component (A) and the organic polyisocyanate component (B). By having the above configuration, an ink exhibiting high dispersion stability over a wide pH range can be obtained.

[0016] The polyurethane resin used in the aqueous pigment dispersion according to this embodiment contains an active hydrogen atom-containing component (A) which is a quaternary ammonium compound (a1). By including the quaternary ammonium compound (a1), the aqueous pigment dispersion particles are unevenly distributed on absorbent substrates such as fabrics due to ionic interactions, thereby increasing the frequency of pigment presence and, as a result, improving color development (=image density). Furthermore, because the quaternary ammonium compound is ionized by a covalent alkyl group bonded to the nitrogen atom, it remains in an ionized state even after the counterion is lost. In other words, the aqueous pigment dispersion according to this embodiment is dispersion-stable even in environments with a pH of 7 or higher, and can function as an ink for aqueous inkjet printers.

[0017] The quaternary ammonium compound (a1) is a positively charged polyatomic ion represented as NR4+, and is not particularly limited as long as it contains an active hydrogen atom. Examples include the reaction product of an active hydrogen atom-containing component containing a tertiary amino group and a quaternizing agent (a1-2).

[0018] Examples of active hydrogen atom-containing components containing tertiary amino groups include tertiary amino group-containing polyols (a1-1), tertiary amino group-containing polycarboxylic acids, tertiary amino group-containing polyamines, tertiary amino group-containing polyamides, tertiary amino group-containing polyurethane compounds, and tertiary amino group-containing polyurea compounds.

[0019] Examples of tertiary amino group-containing polyols (a1-1) include compounds represented by the following general formula (3) and / or compounds represented by the following general formula (4). [ka] [In general formula (3), R 8 R is an alkyl group having 1 to 24 carbon atoms. 9 and R 10 Each of these is independently an alkylene group having 1 to 20 carbon atoms or an oxyalkylene group having 2 to 20 carbon atoms. [ka] [In general formula (4), R 11 , R 12 Each of these is an alkyl group having 1 to 4 carbon atoms.

[0020] Among the tertiary amino group-containing polyols (a1-1), compounds represented by general formula (3) include N-alkyldialcoholamines and polyoxyalkylene alkylamines.

[0021] In this embodiment, "alkyl" includes linear and branched alkyl groups. Preferably, linear or branched alkyl groups having 1 to 24 carbon atoms, more preferably linear or branched alkyl groups having 1 to 12 carbon atoms, and even more preferably linear or branched alkyl groups having 1 to 4 carbon atoms. Examples of alkyl groups include, in particular, the following: methyl, ethyl, propyl, isopropyl, n-butyl, 2-butyl, 2-butyl, 3-butyl, n-pentyl, 2-pentyl, 2-methylbutyl, 3-methylbutyl, 1,2-dimethylpropyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 2-hexyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl L, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethylbutyl, 2-ethylbutyl, 1-ethyl-2-methylpropyl, n-heptyl, 2-heptyl, 3-heptyl, 2-ethylpentyl, 1-propylbutyl, n-octyl, 2-ethylhexyl, 2-propylheptyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icodecyl, tetracosyl.

[0022] Specific examples of N-alkyldialcoholamines and polyoxyalkylene alkylamines include N-methyldiethanolamine, N-ethyldiethanolamine, N-butyldiethanolamine, N-tert-butyldiethanolamine, N-lauryldiethanolamine, N-stearyldiethanolamine, and poly(n=1~10)oxyethyleneoleylamine.

[0023] Among the tertiary amino group-containing polyols (a1-1), compounds represented by general formula (4) include 3-(diethylamine)-1,2-propanediol, etc.

[0024] The tertiary amino group-containing polycarboxylic acid is not particularly limited, but examples include products with terminal carboxylic acid groups obtained by esterifying the above-mentioned tertiary amino group-containing polyol (a1-1) with a polycarboxylic acid. Specifically, examples include products with terminal carboxylic acid groups obtained by dehydration condensation of an N-alkyldialcoholamine and an aliphatic or aromatic dicarboxylic acid in a molar ratio of functional groups of 1:2: reaction products of N-methyldiethanolamine and succinic acid, and reaction products of N-methyldiethanolamine and terephthalic acid.

[0025] The tertiary amino group-containing polyamine is not particularly limited, but examples include: a product with an amino group at the end obtained by amidation of the above tertiary amino group-containing polycarboxylic acid and a polyamine; a product obtained by adding water to the isocyanate-terminated product obtained by urethane reaction of the above tertiary amino group-containing polyol (a1-1) and an organic polyisocyanate, and then converting the end to an amino group; a product obtained by adding a polyamine to the isocyanate-terminated product and then converting the end to an amino group. Specifically, examples include a product with an amino group at the end obtained by dehydration condensation of an N-alkyldialcoholamine and an aliphatic or aromatic dicarboxylic acid in a molar ratio of functional groups of 1:2, followed by dehydration condensation of a polyamine in a molar ratio of functional groups of 1:2; a reaction product obtained by converting the end to an amino group with water to the isocyanate-terminated product obtained by urethane reaction of an N-alkyldialcoholamine and an aliphatic, alicyclic or aromatic diisocyanate in a molar ratio of functional groups of 1:2; and Examples of products of terminal isocyanate groups include: products of terminal amino groups obtained by dehydrating and condensing polyamines with a functional group molar ratio of 1:2; products of terminal amino groups obtained by dehydrating and condensing N-methyldiethanolamine, succinic acid, and isophorone diamine; products of terminal amino groups obtained by reacting N-methyldiethanolamine, isophorone diisocyanate, and water; products of terminal amino groups obtained by reacting N-methyldiethanolamine, isophorone diisocyanate, and isophorone diamine;

[0026] Examples of tertiary amino group-containing polyamides are not particularly limited, but include products of terminal amide groups obtained by the reaction of the above-mentioned tertiary amino group-containing polycarboxylic acid with ammonia. Specifically, examples include products of terminal amide groups obtained by dehydrating and condensing products of terminal carboxylic acid groups obtained by dehydrating N-alkyldialcoholamine and aliphatic or aromatic dicarboxylic acid in a molar ratio of functional groups of 1:2, followed by ammonia in a molar ratio of functional groups of 1:1: Reaction products of terminal amide groups obtained by adding ammonia to the reaction products of N-methyldiethanolamine and succinic acid and dehydrating them.

[0027] The reactions of tertiary amino group-containing polycarboxylic acids with ammonia include the following [1], [2]. [1] Adding a tertiary amino group-containing polycarboxylic acid and ammonia, and dehydrating the resulting ammonium salt to produce a tertiary amino group-containing polyamide. [2] A tertiary amino group-containing polycarboxylic acid and ammonia are added to produce a tertiary amino group-containing polyamide and an alcohol by transesterification.

[0028] The tertiary amino group-containing polyurethane compounds are not particularly limited, but examples include products obtained by urethane-forming a polyol (a1-1) containing the above-mentioned tertiary amino group with an organic monoisocyanate in a molar ratio of hydroxyl group to isocyanate group of 1:1. Specifically, examples include urethane-containing products obtained by reacting an N-alkyldialcoholamine with an aliphatic, alicyclic, or aromatic monoisocyanate in a molar ratio of functional groups of 1:1: a reaction product of N-methyldiethanolamine and phenylisocyanate.

[0029] Examples of tertiary amino group-containing polyurea compounds are not particularly limited, but include products containing a urea group obtained by adding ammonia or an organic monoamine to the isocyanate-terminated product obtained by urethane reaction of a tertiary amino group-containing polyol (a1-1) and an organic polyisocyanate. Specifically, examples include urea-containing products obtained by reacting ammonia or a monoamine with an ammonia-terminated product obtained by urethane reaction of an aliphatic, alicyclic, or aromatic diisocyanate with an aliphatic, alicyclic, or aromatic diisocyanate in a molar ratio of functional groups of 1:2, and an ammonia-terminated product obtained by reacting an ammonia-terminated product obtained by urethane reaction of an aliphatic, alicyclic, or aromatic diisocyanate in a molar ratio of functional groups of 1:1: N-methyldiethanolamine, and products obtained by reacting piperidine with the product obtained by reacting an isocyanate-terminated product obtained by reacting isophorone diisocyanate.

[0030] Examples of quaternizing agents (a1-2) include alkyl halides, dialkyl sulfates, and trialkyl phosphates. Specific examples include ethyl bromide, ethyl iodide, dimethyl sulfate, diethyl sulfate, dipropyl sulfate, dibutyl sulfate, and trimethyl phosphate. Of these, dimethyl sulfate and diethyl sulfate are preferred from the viewpoint of reaction rate.

[0031] In this embodiment, the quaternary ammonium compound (a1) is a compound represented by the following general formula (1) and / or a compound represented by the following general formula (2). [ka] [In general formula (1), R1 and R2 are each independently alkyl groups having 1 to 24 carbon atoms, R3 and R4 are each independently alkylene groups having 1 to 20 carbon atoms or oxyalkylene groups having 2 to 20 carbon atoms, and X- is an anion.] [ka] [In general formula (2), R5 to R7 are each independently alkyl groups having 1 to 4 carbon atoms, and X- is an anion.]

[0032] In this embodiment, the quaternary ammonium compound (a1) is a product obtained by reacting a compound represented by general formula (1) and / or a tertiary amino group-containing polyol (a1-1) represented by general formula (2) with a quaternizing agent (a1-2) in a molar ratio of the compounds = 1:1.

[0033] Specific examples of quaternary ammonium compounds (a1) represented by general formula (1) include: reaction products of N-methyldiethanolamine with any of ethyl bromide, ethyl iodide, dimethyl sulfate, diethyl sulfate, dipropyl sulfate, dibutyl sulfate, or trimethyl phosphate; reaction products of N-ethyldiethanolamine with any of ethyl bromide, ethyl iodide, dimethyl sulfate, diethyl sulfate, dipropyl sulfate, dibutyl sulfate, or trimethyl phosphate; reaction products of N-butyldiethanolamine with any of ethyl bromide, ethyl iodide, dimethyl sulfate, diethyl sulfate, dipropyl sulfate, dibutyl sulfate, or trimethyl phosphate; and reaction products of N-tert-butyldiethanolamine with ethyl bromide, ethyl iodide, or sulfuric acid. Examples of reaction products include those with dimethyl sulfate, diethyl sulfate, dipropyl sulfate, dibutyl sulfate, or trimethyl phosphate; those with N-lauryldiethanolamine and ethyl bromide, ethyl iodide, dimethyl sulfate, diethyl sulfate, dipropyl sulfate, dibutyl sulfate, or trimethyl phosphate; those with N-stearyldiethanolamine and ethyl bromide, ethyl iodide, dimethyl sulfate, diethyl sulfate, dipropyl sulfate, dibutyl sulfate, or trimethyl phosphate; and those with poly(n=1~10)oxyethyleneoleylamine and ethyl bromide, ethyl iodide, dimethyl sulfate, diethyl sulfate, dipropyl sulfate, dibutyl sulfate, or trimethyl phosphate. Of these, from the viewpoint of nitrogen atomic weight relative to the weight of the quaternary ammonium compound (a1) (from the viewpoint of hydrophilicity), the reaction products of N-methyldiethanolamine, N-ethyldiethanolamine, N-butyldiethanolamine, N-tert-butyldiethanolamine, N-lauryldiethanolamine, N-stearyldiethanolamine, and poly(n=1~10)oxyethyleneoleylamine with dimethyl sulfate or diethyl sulfate are preferred, the reaction products of N-methyldiethanolamine and N-ethyldiethanolamine with dimethyl sulfate or diethyl sulfate are more preferred, and the reaction product of N-methyldiethanolamine with dimethyl sulfate is even more preferred.

[0034] Specific examples of quaternary ammonium compounds (a1) represented by general formula (2) include reaction products of 3-(diethylamine)-1,2-propanediol with any of the following: ethyl bromide, ethyl iodide, dimethyl sulfate, diethyl sulfate, dipropyl sulfate, dibutyl sulfate, and trimethyl phosphate. Of these, from the viewpoint of nitrogen atomic weight relative to the weight of the quaternary ammonium compound (a1) (from the viewpoint of hydrophilicity), the reaction product of 3-(diethylamine)-1,2-propanediol and dimethyl sulfate or diethyl sulfate is preferred.

[0035] In the polyurethane resin according to this embodiment, the weight percentage of the quaternary ammonium compound (a1) is 12% by weight or more, preferably 12-60% by weight, more preferably 12-50% by weight, and even more preferably 12-42% by weight, based on the total weight of the active hydrogen atom-containing component (A) and the organic polyisocyanate component (B). If the weight percentage of the quaternary ammonium compound (a1) is less than 12% by weight, the pigment aqueous dispersion particles become coarser, and the initial dispersibility deteriorates.

[0036] The active hydrogen atom-containing component (A) may contain polyols other than the quaternary ammonium compound (a1). Examples of polyols other than the quaternary ammonium compound (a1) include polycarbonate polyols, polyester polyols, polyether polyols, and low molecular weight polyols. The polyol other than the quaternary ammonium compound (a1) preferably contains at least one of the polycarbonate polyols, polyester polyols, and polyether polyols, more preferably polycarbonate polyols, and particularly preferably crystalline polycarbonate polyols.

[0037] Examples of polycarbonate diols include those produced by condensing a low molecular weight dihydric alcohol having a number average molecular weight (Mn) of less than 300 with a low molecular weight carbonate compound (for example, a dialkyl carbonate with an alkyl group having 1 to 10 carbon atoms, an alkylene carbonate having an alkylene group with 2 to 6 carbon atoms, and a diaryl carbonate having an aryl group with 6 to 9 carbon atoms) while undergoing a dealcoholization reaction. Two or more types of low molecular weight dihydric alcohols and alkylene carbonates may be used in combination. The low molecular weight dihydric alcohol may contain trivalent or higher alcohols.

[0038] Specific examples of polycarbonate diols include aliphatic polycarbonates such as polyhexamethylene carbonate diol, polydecamethylene carbonate diol, polypentamethylene carbonate diol, 3-methyl-5-pentane-carbonate diol, polytetramethylene carbonate diol, and poly(tetramethylene / hexamethylene) carbonate diol (for example, a diol obtained by condensing 1,4-butanediol and 1,6-hexanediol with a dialkyl carbonate while de-alcoholizing). Examples of alicyclic polycarbonate diols include polycyclohexamethylene carbonate diol and polynorbornene carbonate diol. Examples of aromatic polycarbonates include poly1,4-xylylene carbonate diol, bisphenol A type polycarbonate diol, and bisphenol F type polycarbonate diol.

[0039] Commercially available polycarbonate diols include Ethanol UH-200 [polyhexamethylene carbonate diol with Mn=2,000, manufactured by Ube Industries, Ltd.], Ethanol UH-100 [polyhexamethylene carbonate diol with Mn=1,000, manufactured by Ube Industries, Ltd.], Ethanol UC-100 [polycyclohexamethylene carbonate diol with Mn=1,000, manufactured by Ube Industries, Ltd.], and Benebi. Examples include All NL2010DB [polydecamethylene carbonate diol with Mn=2,000, manufactured by Mitsubishi Chemical Corporation], Duranol T5651 [polypentamethylene and hexamethylene carbonate diol with Mn=1,000, manufactured by Asahi Kasei Chemicals Corporation], and Duranol G4672 [polytetramethylene and hexamethylene carbonate diol with Mn=1,000, manufactured by Asahi Kasei Chemicals Corporation].

[0040] In one embodiment, the polycarbonate diol in this embodiment is more preferably a crystalline polycarbonate polyol.

[0041] In this embodiment, crystallinity means that when the transition temperature of the sample is measured using a differential scanning calorimeter (DSC) in accordance with the method described in JIS K7121, an endothermic peak peak top temperature exists. The measurement conditions for the peak top temperature of the endothermic peak are described below. Measurements are taken using a differential scanning calorimeter (e.g., TA Instruments Q2000). The sample is first heated from 20°C to 150°C at a rate of 10°C / min, then cooled from 150°C to 0°C at a rate of 10°C / min, and then heated again from 0°C to 150°C at a rate of 10°C / min. The temperature at which the endothermic peak peaks during the second heating process are shown is defined as the endothermic peak peak temperature.

[0042] By including a polyol component containing crystalline polycarbonate polyol in its constituent monomers (constituent units), polyurethane resin can improve its mechanical strength, thereby improving its abrasion resistance.

[0043] Examples of crystalline polycarbonate polyols include polycarbonate diols produced by condensing a saturated low molecular weight aliphatic or alicyclic dihydric alcohol with a low molecular weight carbonate compound (for example, dialkyl carbonates with C1-C10 alkyl groups, alkylene carbonates with C2-C6 alkylene groups, and diaryl carbonates with C6-C9 aryl groups) while de-alcoholizing them. Two or more types of low molecular weight dihydric alcohols and alkylene carbonates may be used in combination, but from the viewpoint of crystallinity, the content of one alcohol raw material is preferably 70-100% by weight, and more preferably 100% by weight.

[0044] Specific examples of crystalline polycarbonate diols include polyhexamethylene carbonate diol, polydecamethylene carbonate diol, and polycyclohexamethylene carbonate diol.

[0045] Examples of polyester polyols include condensed polyester diols, polylactone diols, and castor oil-based diols.

[0046] Condensed polyester diols are polyester diols formed by a dihydric alcohol with a number-average molecular weight (Mn) of less than 300 and a dicarboxylic acid having 2 to 10 carbon atoms or its ester-forming derivative.

[0047] As low molecular weight dihydric alcohols, low molar adducts of dihydric aliphatic dihydric alcohols with Mn less than 300 and dihydric phenol alkylene oxides (hereinafter sometimes abbreviated as AO) with Mn less than 300 can be used. Examples of AOs include ethylene oxide (hereinafter sometimes abbreviated as EO), propylene oxide (hereinafter sometimes abbreviated as PO), 1,2-, 1,3-, 2,3-, or 1,4-butylene oxide, etc. Among the low molecular weight dihydric alcohols that can be used in condensed polyester polyols, preferred are ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexaneglycol, 1,9-nonanediol, 1,10-decanediol, EO or PO low molar adducts of bisphenol A, and combinations thereof. The condensed polyester diol may contain trivalent or higher alcohols and trivalent or higher carboxylic acids or their ester-forming derivatives as constituent components.

[0048] Examples of dicarboxylic acids having 2 to 10 carbon atoms or their ester-forming derivatives that can be used in condensed polyester diols include aliphatic dicarboxylic acids (such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanediic acid, fumaric acid, and maleic acid), alicyclic dicarboxylic acids (such as dimer acid), aromatic dicarboxylic acids (such as terephthalic acid, isophthalic acid, and phthalic acid), their anhydrides (such as succinic anhydride, maleic anhydride, and phthalic anhydride), their acid halides (such as adipic acid dichloride), their low molecular weight alkyl esters (such as dimethyl succinate and dimethyl phthalate), and combinations thereof. Examples of trivalent or higher polycarboxylic acids include trimellitic acid and pyromellitic acid.

[0049] Specific examples of condensed polyester polyols include polyethylene adipate diol, polybutylene adipate diol, polyhexamethylene adipate diol, polyhexamethylene isophthalate diol, polyhexamethylene terephthalate diol, polyneopentyl adipate diol, polyethylene propylene adipate diol, polyethylene butylene adipate diol, polybutylene hexamethylene adipate diol, polydiethylene adipate diol, poly(polytetramethylene ether) adipate diol, poly(3-methylpentylene adipate) diol, polyethylene azelate diol, polyethylene sebacate diol, polybutylene azelate diol, polybutylene sebacate diol, and polyneopentyl terephthalate diol.

[0050] Commercially available condensed polyester polyols include SunEster 2610 [polyethylene adipate diol with Mn=1,000, manufactured by Sanyo Chemical Industries, Ltd.], SunEster 4620 [polytetramethylene adipate diol with Mn=2,000], and SunEster 26 20 [Polyethylene adipate diol with Mn=2,000, manufactured by Sanyo Chemical Industries, Ltd.], Kuraray Polyol P-2010 [Poly-3-methyl-1,5-penta with Mn=2,000] [Adipate diol], Kuraray polyol P-3010 [Mn=3,000 poly-3 -Methyl-1,5-pentaneadipatediol], Kuraray Polyol P-6010 [Mn=6,000 poly-3-methyl-1,5-pentaneadipatediol], Kuraray Liol P-2020 [Mn=2,000 poly-3-methyl-1,5-pentanetereph [Talatediol], P-2030[Mn=2,000 poly-3-methyl-1,5-pe Examples include [tan-isophthalate diol].

[0051] Polylactone diols are polyadditions of lactones to the low molecular weight dihydric alcohols mentioned above. Examples of lactones include lactones with 4 to 12 carbon atoms (e.g., γ-butyrolactone, γ-valerolactone, and ε-caprolactone). Specific examples of polylactone polyols include, for example, polycaprolactone diol, polyvalerolactone diol, and polycaprolactone triol.

[0052] Castor oil-based polyols include castor oil and modified castor oil modified with polyols or AO. Modified castor oil can be produced by transesterification and / or AO addition of castor oil and polyol. Examples of castor oil-based polyols include castor oil, trimethylolpropane-modified castor oil, pentaerythritol-modified castor oil, and EO (4-30 mol) adducts of castor oil.

[0053] Examples of polyether polyols include aliphatic polyether diols and aromatic ring-containing polyether diols.

[0054] Examples of aliphatic polyether diols include polyoxyethylene polyols [polyethylene glycol (hereinafter abbreviated as PEG) etc.], polyoxypropylene polyols [polypropylene glycol etc.], polyoxyethylene / propylene polyols and polytetramethylene ether glycol.

[0055] Commercially available aliphatic polyether diols include PTMG1000 [polytetramethylene ether glycol with Mn=1,000, manufactured by Mitsubishi Chemical Corporation], PTMG2000 [polytetramethylene ether glycol with Mn=2,000, manufactured by Mitsubishi Chemical Corporation], PTMG3000 [polytetramethylene ether glycol with Mn=3,000, manufactured by Mitsubishi Chemical Corporation], PTGL3000 [modified PTMG with Mn=3,000, manufactured by Hodogaya Chemical Co., Ltd.], and Sannix Diol GP-3000 [polypropylene ether triol with Mn=3,000, manufactured by Sanyo Chemical Industries, Ltd.].

[0056] Examples of aromatic polyether diols include polyols having a bisphenol skeleton, such as EO adducts of bisphenol A [e.g., 2-mol EO adduct of bisphenol A, 4-mol EO adduct of bisphenol A, 6-mol EO adduct of bisphenol A, 8-mol EO adduct of bisphenol A, 10-mol EO adduct of bisphenol A, and 20-mol EO adduct of bisphenol A] and PO adducts of bisphenol A [e.g., 2-mol PO adduct of bisphenol A, 3-mol PO adduct of bisphenol A, 5-mol PO adduct of bisphenol A], as well as EO or PO adducts of resorcinol.

[0057] Examples of low molecular weight polyols include the above-mentioned aliphatic diols having 2 to 20 carbon atoms, preferably diols having a branched structure with 4 to 10 carbon atoms, more preferably 3-methyl-1,5-pentanediol and neopentyl glycol, and even more preferably 3-methyl-1,5-pentanediol. Using a low molecular weight polyol having a branched structure is preferable because it reduces the cohesive force between hard segments (urethane bonding sites) in the polyurethane resin, improving solvent solubility, flexibility of the coating film, and excellent initial dispersibility (especially reducing particle size). When the active hydrogen atom-containing component (A) contains a low molecular weight polyol, the amount of the low molecular weight polyol is preferably 0.1 to 4.5% by weight, and more preferably 0.3 to 2% by weight, relative to the total weight of the active hydrogen atom-containing component (A) and the organic polyisocyanate component (B).

[0058] Examples of organic polyisocyanate components (B) used in polyurethane resins include aliphatic polyisocyanates having 2 to 18 carbon atoms and possessing two or more isocyanate groups, alicyclic polyisocyanates having 4 to 15 carbon atoms, aromatic polyisocyanates having 6 to 20 carbon atoms (excluding carbon atoms in the isocyanate groups, the same applies hereinafter), aromatic aliphatic polyisocyanates having 8 to 15 carbon atoms, and derivatives of these polyisocyanates (e.g., isocyanurates). The polyisocyanate component may be used alone, or two or more may be used in combination.

[0059] Examples of aliphatic polyisocyanates having 2 to 18 carbon atoms include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, and 2-isocyanatoethyl-2,6-diisocyanatohexanoate.

[0060] Examples of alicyclic polyisocyanates having 4 to 15 carbon atoms include isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4-diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), bis(2-isocyanatoethyl)-4-cyclohexene-1,2-dicarboxylate, and 2,5- or 2,6-norbornane diisocyanate.

[0061] Examples of aromatic polyisocyanates having 6 to 20 carbon atoms include 1,3- or 1,4-phenylenediisocyanate, 2,4- or 2,6-tolylenediisocyanate (TDI), 4,4'- or 2,4'-diphenylmethanediisocyanate (MDI), 1,5-naphthylenediisocyanate, 4,4',4''-triphenylmethanetriisocyanate, m- or p-isocyanatophenylsulfonyl isocyanate, crude MDI, and the like.

[0062] Examples of aromatic aliphatic polyisocyanates having 8 to 15 carbon atoms include m- or p-xylylene diisocyanate (XDI) and α,α,α',α'-tetramethylxylylene diisocyanate (TMXDI).

[0063] From the viewpoint of initial dispersibility and mechanical strength of the aqueous pigment dispersion, the organic polyisocyanate component (B) is preferably an aromatic polyisocyanate having 6 to 20 carbon atoms or an alicyclic polyisocyanate having 4 to 15 carbon atoms, and TDI, IPDI, and hydrogenated MDI are more preferred.

[0064] The equivalent ratio (NCO / OH) of isocyanate groups contained in the organic polyisocyanate component (B) and hydroxyl groups contained in the active hydrogen atom-containing component (A) is preferably 1.2 to 1.8, and more preferably 1.3 to 1.6, from the viewpoint of homogenizing the compositional distribution of the polyurethane resin and mechanical strength.

[0065] Polyurethane resins primarily consist of the above-mentioned active hydrogen atom-containing component (A) and organic polyisocyanate component (B) as essential constituent monomers (constituent units), but may also contain compounds other than the active hydrogen atom-containing component (A) and organic polyisocyanate component (B) as constituent monomers. Examples of constituent monomers other than the active hydrogen atom-containing component (A) and organic polyisocyanate component (B) include chain extenders and reaction inhibitors. These may be used individually or in combination of two or more. In one embodiment, the polyurethane resin is preferably a reaction product of a urethane prepolymer having isocyanate groups at its termini, obtained by reacting the above-mentioned active hydrogen atom-containing component (A) and organic polyisocyanate component (B), and a chain extender.

[0066] It is preferable to use a chain extender in polyurethane resins. Examples of chain extenders include water, C2-C10 diamines (e.g., ethylenediamine, propylenediamine, hexamethylenediamine, isophoronediamine, toluenediamine, and piperazine), C2-C10 polyalkylene polyamines (e.g., diethylenetriamine, triethylenetetramine, and tetraethylenepentamine), hydrazine or its derivatives (dibasic acid dihydrazides, e.g., adipic acid dihydrazide), C2-C30 polyepoxy compounds (e.g., 1,6-hexanediol diglycidyl ether, trimethylolpropane polyglycidyl ether, etc.), and C2-C10 amino alcohols (e.g., ethanolamine, diethanolamine, 2-amino-2-methylpropanol, and triethanolamine). C2-C10 diamines are preferred as chain extenders, secondary diamines are more preferred, and isophoronediamine is even more preferred. When a polyurethane resin contains the above compound as a constituent monomer, the cohesive force of the urethane group portion is improved, and the degree of swelling in water is reduced, resulting in excellent wet friction fastness. Furthermore, the use of diamines is preferable because the generation of carbon dioxide is suppressed by the extension reaction caused by the amine, and the amount of amine carbonate salt produced is reduced, thereby improving storage stability.

[0067] The amount of chain extender used is preferably in the range of 0.2 to 2, and more preferably in the range of 0.5 to 1.5, where the ratio of the equivalent amount of the active hydrogen-containing group of the chain extender to the isocyanate group at the end of the urethane prepolymer is 0.2 to 2.

[0068] Reaction inhibitors may be used with polyurethane resins as needed. Examples of reaction inhibitors include monoalcohols with 1 to 8 carbon atoms (methanol, ethanol, isopropanol, cellosolves, and carbitols, etc.) and monoamines with 1 to 10 carbon atoms (mono- or dialkylamines such as monomethylamine, monoethylamine, monobutylamine, dibutylamine, and monooctylamine; mono- or dialkanolamines such as monoethanolamine, diethanolamine, and diisopropanolamine, etc.).

[0069] Examples of methods for producing the polyurethane resin according to this embodiment include the following methods [1] to [4]. [1] A method for producing a polyurethane resin having isocyanate groups at its termini by reacting a polyol component, a tertiary amino group-containing polyol (a1-1), and a polyisocyanate component in one or multiple steps in the presence or absence of a hydrophilic solvent, and then carrying out a quaternization reaction with a quaternizing agent (a1-2). [2] A method for producing a polyurethane resin by reacting a tertiary amino group-containing polyol (a1-1) and a quaternizing agent (a1-2) in one or multiple steps in the presence or absence of a hydrophilic solvent to produce a quaternary ammonium compound (a1), and then reacting the polyol component and polyisocyanate component in one or multiple steps. [3] A method for producing a polyurethane resin having isocyanate groups at the ends by reacting a polyol component, a tertiary amino group-containing polyol (a1-1) and a polyisocyanate component in one or multiple steps in the presence or absence of a hydrophilic solvent, then reacting the isocyanate groups in the polyurethane resin with a chain extender and / or reaction stopper, and finally carrying out a quaternization reaction with a quaternizing agent (a1-2). [4] A method for producing a polyurethane resin having isocyanate groups at the ends by reacting a polyol component, a tertiary amino group-containing polyol (a1-1) and a polyisocyanate component in one or multiple steps in the presence or absence of a hydrophilic solvent, and then carrying out a quaternization reaction with a quaternizing agent (a1-2). Subsequently, the resin is dispersed in an aqueous medium, and the isocyanate groups in the polyurethane resin are reacted with a chain extender and / or reaction stopper, after which the hydrophilic solvent is removed by distillation as necessary. The polyurethane resins produced by the methods described in [1] to [4] above can be used in the production of aqueous pigment dispersions. Of these, methods [1] to [3] are more preferred from the viewpoint of storage stability of the aqueous pigment dispersion.

[0070] Hydrophilic solvents used in the production of the polyurethane resin described above [3] include those that are substantially inactive with the NCO group (acetone, ketones such as ethyl methyl ketone, esters, ethers, amides, and alcohols). Of these, tetrahydrofuran is preferred. The aqueous medium may be water alone, but a mixture of water and hydrophilic solvent can also be used. The weight ratio of hydrophilic solvent to water (hydrophilic solvent / water) is preferably 0 / 100 to 50 / 50, and more preferably 35 / 65 to 45 / 55. If a hydrophilic solvent is used, it may be removed by distillation after the polyurethane resin is manufactured, if necessary.

[0071] The formation of the polyurethane resin is preferably carried out by a reaction at 20°C to 150°C, more preferably 60°C to 110°C, with a reaction time of preferably 2 to 20 hours. Polyurethane resins can be synthesized in or out of the presence of an organic solvent that is substantially inactive with NCO groups. Polyurethane resins having isocyanate groups at their ends typically have a free NCO group content of 0.5 to 10%. Examples of organic solvents that are substantially inactive with NCO groups include the hydrophilic solvents mentioned above, with tetrahydrofuran being preferred.

[0072] In the production of polyurethane resins, catalysts commonly used in conventional urethane reactions may be used to accelerate the reaction, if necessary. Examples of catalysts include amine catalysts, such as triethylamine, N-ethylmorpholine, triethylenediamine, and cycloamidines described in U.S. Patent No. 4,524,104 [e.g., 1,8-diaza-bicyclo(5,4,0)undecene-7 (manufactured by Sunapro, DBU)]; tin-based catalysts, such as dibutyltin dilaurylate, dioctyltin dilaurylate, and tin octoate; and titanium-based catalysts, such as tetrabutyl titanate.

[0073] The isocyanate group content of polyurethane resin can be measured by the method specified in JIS K1603-1. In the examples of this embodiment, the isocyanate group content (NCO wt%) of the solvent solution was used.

[0074] The urea group content based on the weight of the polyurethane resin is preferably 0.01 to 0.2% by weight, more preferably 0.05 to 0.1% by weight. A urea group content of 0.01 to 0.2% by weight (preferably 0.05 to 0.1% by weight) in the polyurethane resin (U) is preferable because it provides an appropriate urea group content in the polyurethane resin, allowing for a balance between mechanical strength and viscosity of the aqueous dispersion.

[0075] Examples of pigments in this embodiment include conventionally known organic and inorganic pigments (for example, white pigments, black pigments, gray pigments, red pigments, brown pigments, yellow pigments, green pigments, blue pigments, purple pigments and metallic pigments, naturally occurring organic pigments, synthetic organic pigments, nitroso pigments, nitro pigments, pigment-type azo pigments, azo lakes made from water-soluble dyes, azo lakes made from poorly soluble dyes, lakes made from basic dyes, lakes made from acid dyes, xanthan lakes, anthraquinone lakes, pigments from vat dyes and phthalocyanine pigments, and organic pigments such as daylight fluorescent pigments).

[0076] Examples of specific organic and inorganic pigments are given below. Examples of white pigments include inorganic pigments such as titanium dioxide, zinc oxide, zinc sulfide, antimony oxide, and zirconium oxide. In addition to inorganic pigments, hollow resin microparticles and polymer microparticles can also be used. The average particle size of the pigment is preferably 200 to 300 nm. If the average particle size of the pigment is less than 200 nm, the opacity tends to be insufficient, and if it exceeds 300 nm, the discharge stability tends to be insufficient.

[0077] In particular, titanium dioxide is preferred from the viewpoint of opacity. Similarly, the average particle size of titanium dioxide is preferably 200 to 300 nm.

[0078] Examples of pigments for magenta include CI Pigment Red 2, CI Pigment Red 3, CI Pigment Red 5, CI Pigment Red 6, CI Pigment Red 7, CI Pigment Red 15, CI Pigment Red 16, CI Pigment Red 48:1, CI Pigment Red 53:1, CI Pigment Red 57:1, CI Pigment Red 122, CI Pigment Red 123, CI Pigment Red 139, CI Pigment Red 144, CI Pigment Red 149, CI Pigment Red 166, CI Pigment Red 177, CI Pigment Red 178, and CI Pigment Red 222.

[0079] Pigments for yellow are not particularly limited, but examples include CI Pigment Orange 31, CI Pigment Orange 43, CI Pigment Yellow 12, CI Pigment Yellow 13, CI Pigment Yellow 14, CI Pigment Yellow 15, CI Pigment Yellow 17, CI Pigment Yellow 74, CI Pigment Yellow 93, CI Pigment Yellow 94, CI Pigment Yellow 128, CI Pigment Yellow 138, CI Pigment Yellow 155, and Pigment Yellow 180.

[0080] Pigments for cyan are not particularly limited, but examples include CI Pigment Blue 15, CI Pigment Blue 15:2, CI Pigment Blue 15:3, CI Pigment Blue 15:4, CI Pigment Blue 16, CI Pigment Blue 60, and CI Pigment Green 7.

[0081] Examples of black pigments include carbon blacks (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black; metals such as copper and iron (CI Pigment Black 11); metal compounds such as titanium dioxide; and organic pigments such as aniline black (CI Pigment Black 1).

[0082] In this embodiment, the total weight of the pigment and polyurethane resin in the aqueous pigment dispersion is preferably 10 to 40% by weight, and more preferably 20 to 30% by weight, from the viewpoint of storage stability.

[0083] In this embodiment, the ratio of pigment to polyurethane resin in the aqueous pigment dispersion is preferably 60:40 to 40:60 from the viewpoint of initial dispersibility and friction fastness.

[0084] In aqueous pigment dispersions, particles consisting of pigment and polyurethane resin are typically dispersed in water. From the viewpoint of storage stability and viscosity, the particle size of the particles in the aqueous pigment dispersion is preferably 100 to 200 nm, more preferably 120 to 180 nm for colored pigments, and preferably 200 to 400 nm, more preferably 220 to 300 nm for white pigments. In this embodiment, particle size refers to the cumulant average diameter. The particle size can be measured and determined using a light scattering particle size distribution analyzer [for example, "DLS-8000" manufactured by Otsuka Electronics Co., Ltd.].

[0085] All conventionally known methods can be used to produce aqueous pigment dispersions. Conventionally known methods include surface polymerization, in which monomers are adsorbed and polymerized on the surface of the pigment dispersion; surface deposition, in which pigments are dispersed in a resin solution, a poor solvent is added to the resin, and the resin is deposited on the pigment surface; kneading and micronization, in which pigments and resins are melt-kneaded to form a masterbatch and then micronized wet; a method that simultaneously achieves micronization and coating by the penetration of a resin solution into pigment aggregates using a high-pressure fluid and the expansion energy when released under atmospheric pressure; a method that micronizes an aqueous dispersion of pigments and resins wet and disperses it using mechanical energy; and a phase inversion emulsification method in which a resin solution and pigment that are self-dispersible in water are micronized wet, and water is added to the solvent phase to obtain an aqueous pigment dispersion. Of these, the methods most suitable for producing the aqueous pigment dispersion according to this embodiment are, from the viewpoint of initial dispersibility and storage stability, a method in which the aqueous pigment and resin dispersion are micronized in a wet manner and dispersed by mechanical energy, and a phase inversion emulsification method. In the method of dispersing pigments and aqueous resin dispersions using mechanical energy, and in the phase inversion emulsification method, the surface of the pigment particles is adsorbed or coated with a self-dispersing polyurethane resin that forms a coating film. Therefore, the pigment, which is the coloring agent, can be fixed onto the substrate without adding other binder resins to the ink, which is preferable from the viewpoint of colorfastness. The phase inversion emulsification method is preferable from the viewpoint of storage stability because, as it creates a structure in which the pigment surface is covered with resin, the frequency of exposure of the pigment surface in the ink is low, there is no compositional distribution as dispersed particles, and structural changes are less likely to occur.

[0086] -Method for producing aqueous pigment dispersions- Examples of the aqueous pigment dispersion according to this embodiment include the following methods [A] to [C]. [A] A method in which a pigment is added to a polyurethane resin solution having isocyanate group terminators as described in the method of [1] above, mixed and homogenized, then the solvent solution containing the pigment is micronized by mechanical crushing, and after micronization, the carboxyl groups are emulsified and dispersed in an aqueous medium as salts with a neutralizing agent, and the chain extender and / or reaction stopper reacts with the isocyanate groups in the polyurethane resin, and then the hydrophilic solvent is removed by distillation as necessary. [B] A method in which a pigment is added to the polyurethane resin solution described in the method of [2] above, mixed and homogenized, then the solvent solution containing the pigment is micronized by mechanical crushing, and after micronization, the carboxyl groups are emulsion-dispersed in an aqueous medium as salts with a neutralizing agent, and hydrophilic solvent is removed by distillation if necessary. [C] A method of adding a pigment to a polyurethane resin dispersion as described in [3] above, mixing and homogenizing it, and then micronizing the aqueous dispersion containing the pigment by mechanical crushing.

[0087] Furthermore, in the manufacturing methods [A] to [C] described above, the equipment used for mixing and homogenization can be the same equipment used for synthesizing polyurethane resin. Examples of dispersers used for micronization include paint shakers, ball mills, sand mills, and nanomills. Specifically, examples include Dynomill (manufactured by Shinmaru Enterprise) and TSU-6U (manufactured by AIMEX).

[0088] In the methods for producing aqueous pigment dispersions [A] and [B], the apparatus for emulsifying and dispersing in an aqueous medium is not particularly limited, and examples include the emulsifier of the following type. 1) Anchor-type stirring method, 2) Rotor-stator type [e.g., "Ebara Milder" (manufactured by Ebara Corporation)], 3) Line mill type [e.g., line flow mixer], 4) Stationary tube mixing type [e.g., static mixer], 5) Vibration type [e.g., "VIBROMIXER" (manufactured by Reika Kogyo Co., Ltd.)], 6) Ultrasonic impact type [e.g., ultrasonic homogenizer], 7) High-pressure impact type [e.g., Gaurin homogenizer (Gaurin Corporation)], 8) Emulsification type [e.g., membrane emulsification module], and 9) Centrifugal thin film contact type [e.g., Filmix]. Of these, the anchor-type stirring method is preferred.

[0089] The aqueous pigment dispersion may contain additives such as surfactants, crosslinking agents, weather stabilizers, and smoothing agents as needed. The additives may be used individually or in combination of two or more. The amount of additive used is preferably 15% by weight or less, more preferably 10% by weight or less, and even more preferably 5% by weight or less, based on the total weight of the pigment and polyurethane resin.

[0090] In one embodiment, the aqueous pigment dispersion of this embodiment preferably contains a surfactant. When the aqueous pigment dispersion of this embodiment contains a surfactant, the storage stability after heating and the dry friction fastness of the aqueous pigment dispersion are improved. The surfactant is preferably added when manufacturing the aqueous pigment dispersion.

[0091] When a surfactant is used in the production of an aqueous pigment dispersion, the surfactant may be added at any stage in the production process. In one embodiment, from the viewpoint of pigment dispersibility and the stability of the aqueous dispersion, it is preferable to add the surfactant before or during the dispersion of the pigment in the polyurethane resin. The surfactant may be added to either the solvent solution of the polyurethane resin, the aqueous medium, or both. If the surfactant is reactive with the urethane prepolymer, it is preferable to add it to the aqueous medium. The amount of surfactant added is preferably 0.2 to 10% by weight, more preferably 0.3 to 6% by weight, based on the weight of the pigment.

[0092] Examples of surfactants include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and other emulsifying and dispersing agents. One type of surfactant may be used, or two or more types may be used in combination. Among these, nonionic surfactants are preferred.

[0093] Nonionic surfactants include aliphatic alcohol (8-24 carbon atoms) AO (2-8 carbon atoms) adducts (degree of polymerization = 1-100), polyhydric alcohol (3-18 carbon atoms) AO (2-8 carbon atoms) adducts (degree of polymerization = 1-100), (poly)oxyalkylene (2-8 carbon atoms, degree of polymerization = 1-100), higher fatty acid (8-24 carbon atoms) esters [e.g., polyethylene glycol monooleate (HLB = 6-17), polyethylene glycol monostearate (HLB = 8-15), polyethylene glycol distearate (HLB = 8-14), and other mono or di-fatty acid polyethylene glycol esters], polyhydric (2-10 or more) alcohol fatty acid (8-24 carbon atoms) esters [glyceryl monostearate, ethylene glycol monostearate, sorbitan fatty acid ester (sorbitan monooleate)], Examples include polyoxyalkylene (carbons 2-8, degree of polymerization = 1-100), polyvalent (divalent to decadal or higher) alcohol higher fatty acid (carbons 8-24) esters [polyoxyethylene sorbitan monolaurate (HLB = 10-16), polyoxyethylene dioleate methyl glucoside (HLB = 17), etc.], fatty acid alkanolamides [1:1 type coconut oil fatty acid diethanolamide, 1:1 type lauric acid diethanolamide, etc.], polyoxyalkylene (carbons 2-8, degree of polymerization = 1-100) alkyl (carbons 1-22) phenyl ethers, polyoxyalkylene (carbons 2-8, degree of polymerization = 1-100) alkyl (carbons 8-24) amino ethers and alkyl (carbons 8-24) dialkyl (carbons 1-6) amine oxides [lauryldimethylamine oxide, etc.]. Among these, mono- or di-fatty acid polyethylene glycol esters such as aliphatic alcohol (8-24 carbon atoms) AO (2-8 carbon atoms) adducts (HLB=5-18), polyhydric alcohol (3-18 carbon atoms) AO (2-8 carbon atoms) adducts (HLB=11-24), sorbitan monooleate, polyethylene glycol monooleate (HLB=6-17), polyethylene glycol monostearate (HLB=8-15), and polyethylene glycol distearate (HLB=8-14) are preferred. In one embodiment, the aqueous pigment dispersion of this embodiment preferably contains a nonionic surfactant because it exhibits excellent dry friction fastness and stability under heat. Preferred nonionic surfactants include aliphatic alcohol (8-24 carbon atoms) AO (2-8 carbon atoms) adducts (HLB=5-18), polyhydric alcohol (3-18 carbon atoms) AO (2-8 carbon atoms) adducts (HLB=11-24), sorbitan monooleate, and polyethylene glycol monooleate (HLB=6-17).

[0094] Anionic surfactants include, for example, ether carboxylic acids or salts thereof having hydrocarbon groups with 8 to 24 carbon atoms [such as sodium lauryl ether acetate and (poly)oxyethylene (1 to 100 added moles) sodium lauryl ether acetate]; sulfate esters or ether sulfate esters having hydrocarbon groups with 8 to 24 carbon atoms and their salts [such as sodium lauryl sulfate, (poly)oxyethylene (1 to 100 added moles) sodium lauryl sulfate, (poly)oxyethylene (1 to 100 added moles) triethanolamine lauryl sulfate and (poly)oxyethylene (1 to 100 added moles) coconut oil fatty acid monoethanolamide sulfate sodium]; sulfonates having hydrocarbon groups with 8 to 24 carbon atoms [such as sodium dodecylbenzenesulfonate]; hydrocarbon groups with 8 to 24 carbon atoms Examples include sulfosuccinates having one or two hydrocarbon groups; phosphate esters or ether phosphate esters having hydrocarbon groups with 8 to 24 carbon atoms and their salts [e.g., sodium lauryl phosphate and (poly)oxyethylene (1 to 100 moles added) sodium lauryl ether phosphate]; fatty acid salts having hydrocarbon groups with 8 to 24 carbon atoms [e.g., sodium laurate and triethanolamine laurate]; and acylated amino acid salts having hydrocarbon groups with 8 to 24 carbon atoms [e.g., sodium methyl taurate, sodium sarcosinate, triethanolamine sarcosinate, triethanolamine acyl-L-glutamate, sodium acyl-L-glutamate, and sodium lauroylmethyl-β-alanine].

[0095] Examples of cationic surfactants include quaternary ammonium salts [such as stearyltrimethylammonium chloride, behenyltrimethylammonium chloride, distearyldimethylammonium chloride, and lanolin fatty acid aminopropylethyldimethylammonium ethyl sulfate] and amine salts [such as diethylaminoethylamide lactate stearate, dilaurylamine hydrochloride, and oleylamine lactate].

[0096] Examples of amphoteric surfactants include betaine-type amphoteric surfactants [such as coconut oil fatty acid amidopropyl dimethylaminoacetic acid betaine, lauryl dimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, lauryl hydroxysulfobetaine, and lauroylamide ethyl hydroxyethyl carboxymethyl betaine hydroxypropyl sodium phosphate] and amino acid-type amphoteric surfactants [such as β-laurylaminopropionate sodium].

[0097] Other emulsifying dispersants include, for example, polyvinyl alcohol, starch and its derivatives, cellulose derivatives such as carboxymethylcellulose, methylcellulose and hydroxyethylcellulose, carboxyl group-containing (co)polymers such as sodium polyacrylate, and emulsifying dispersants having urethane groups or ester groups as described in U.S. Patent No. 5,906,704 [for example, polylactone polyol and polyetherdiol linked with polyisocyanate].

[0098] If the aqueous pigment dispersion contains a surfactant, its content is preferably 0.2 to 10% by weight, more preferably 0.3 to 6% by weight, based on the weight of the polyurethane resin.

[0099] The aqueous pigment dispersion of this embodiment may contain other components as needed, selected as appropriate. Examples include dispersants, penetrating agents, pH adjusters, water-dispersible resins, preservatives and antifungal agents, chelating reagents, rust inhibitors, antioxidants, UV absorbers, oxygen absorbers, and light stabilizers.

[0100] Using the obtained aqueous pigment dispersion, an aqueous inkjet ink composition with excellent friction fastness and particularly good color development on untreated fabrics can be obtained.

[0101] -Water-based inkjet ink- The ink according to this embodiment contains the aqueous pigment dispersion according to this embodiment, water, and a water-soluble organic solvent.

[0102] In the ink according to this embodiment, the amount of aqueous pigment dispersion blended is preferably 20 to 80% by weight, more preferably 30 to 70% by weight or more, and even more preferably 40 to 60% by weight or more, based on the total amount of ink.

[0103] From the viewpoint of storage stability, the total weight of the pigment and polyurethane resin in the ink according to this embodiment is preferably 5 to 20% by weight, and more preferably 10 to 15% by weight, relative to the total amount of ink.

[0104] In this embodiment, the weight of water in the ink is preferably 50 to 80% by weight, and more preferably 60 to 75% by weight, relative to the total amount of ink.

[0105] -Water-soluble organic solvent- The ink according to this embodiment may contain a water-soluble organic solvent for purposes such as preventing the ink from drying out or improving the dispersion stability of the pigment. There are no particular restrictions on the water-soluble organic solvent, and it can be appropriately selected depending on the purpose.

[0106] The aqueous organic solvent preferably contains a water-soluble solvent with a standard boiling point (hereinafter simply referred to as "bp") of 180°C or higher (hereinafter also referred to as "high-boiling point organic solvent"). Including a high-boiling point organic solvent improves the moisture retention of the nozzle and further enables optimization of the ink viscosity.

[0107] "Standard boiling point" refers to the boiling point at an atmospheric pressure of 0.101 MPa. Note that the high-boiling point organic solvent may be one type or two or more types.

[0108] The content of the high-boiling point organic solvent is preferably 1 to 40% by weight, more preferably 5 to 30% by weight, and more preferably 10 to 25% by weight, relative to the total amount of ink.

[0109] Polyhydric alcohols are preferred as the water-soluble organic solvent. There are no particular restrictions on such polyhydric alcohols, and they can be appropriately selected depending on the purpose. Examples of water-soluble organic solvent A include propylene glycol (bp 188°C), 1,2,3-butanetriol, 1,2,4-butanetriol (bp 190°C~191°C / 24hPa), glycerin (bp 290°C), diglycerin (bp 270°C / 20hPa), triethylene glycol (bp 285°C), tetraethylene glycol (bp 324~330°C), diethylene glycol (bp 245°C), and 1,3-butanediol (bp 203°C~204°C).

[0110] In addition to the aforementioned water-soluble organic solvents, the ink may, if necessary, substitute for some of these water-soluble organic solvents or add other water-soluble organic solvents or solid wetting agents. Examples of the water-soluble organic solvent or solid wetting agent include polyhydric alcohols, polyhydric alcohol alkyl ethers, polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, sulfur-containing compounds, propylene carbonate, ethylene carbonate, and other water-soluble organic solvents.

[0111] Examples of the aforementioned polyhydric alcohols include dipropylene glycol (bp232℃), 1,5-pentanediol (bp242℃), 3-methyl-1,3-butanediol (bp203℃), propylene glycol (bp187℃), 2-methyl-2,4-pentanediol (bp197℃), ethylene glycol (bp196℃~198℃), tripropylene glycol (bp267℃), hexylene glycol (bp197℃), polyethylene glycol (viscous liquid to solid), polypropylene glycol (bp187℃), 1,6-hexanediol (bp253℃~260℃), 1,2-hexanediol (bp170℃), 1,2,6-hexanetriol (bp178℃), trimethylolethane (solid, mp199℃~201℃), and trimethylolpropane (solid, mp61℃). Examples of the aforementioned polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether (bp135°C), ethylene glycol monobutyl ether (bp171°C), diethylene glycol monomethyl ether (bp194°C), diethylene glycol monobutyl ether (bp231°C), ethylene glycol mono-2-ethylhexyl ether (bp229°C), and propylene glycol monoethyl ether (bp132°C). There are no particular restrictions on the content of water-soluble organic solvents in the ink, and it can be appropriately selected depending on the purpose, but 1 to 50% by weight is preferred, and 10 to 30% by weight is more preferred.

[0112] - Surfactants - The ink according to this embodiment preferably contains a surfactant. By including a surfactant, the ink's ejection properties can be improved, its wetting and spreading properties can be improved, and its image quality (color development) can be enhanced.

[0113] Examples of surfactants include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and other emulsifying and dispersing agents. One type of surfactant may be used, or two or more types may be used in combination. Among these, nonionic surfactants are preferred. Examples of nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants are as described above.

[0114] The surfactant preferably contains a nonionic surfactant. By containing a nonionic surfactant, the ink can have improved ejection properties, wetting properties, and overall image quality (color development).

[0115] The surfactant preferably contains an alkyl ether-type nonionic surfactant with an HLB value of 5 to 12. By containing this surfactant, the ink can improve its ejection properties, wetting properties, and overall image quality (color development). In this embodiment, the HLB value refers to the value determined by the Griffin method.

[0116] The content of nonionic surfactant is preferably 0.01 to 10% by weight, more preferably 0.05 to 5% by weight, and even more preferably 0.1 to 3% by weight, relative to the total amount of ink.

[0117] The viscosity of the ink using the aqueous pigment dispersion of this embodiment is preferably 3.0 to 10.0 mPa·s at 25°C, and more preferably 3.5 to 6.0 mPa·s. The viscosity can be measured using a cone plate viscometer under the conditions described in the examples.

[0118] The aqueous inkjet ink containing the aqueous pigment dispersion of this embodiment can be suitably used, for example, as an aqueous inkjet ink for coated paper for printing, corrugated cardboard, and cotton fabrics. The printing method using the aqueous inkjet ink is not particularly limited, but examples include home printing, business printing, sign graphic printing, and pigment textile printing. Pigment textile printing is preferred. [Examples]

[0119] The present invention will be described more specifically below with reference to examples and comparative examples. The present invention is not limited in any way by the following examples. Hereinafter, unless otherwise specified, "parts" refers to parts by weight.

[0120] -Manufacturing Example 1- In a reaction vessel equipped with a condenser, thermometer, stirrer, and nitrogen inlet, 836.9 parts of diethylene glycol, 327.3 parts of terephthalic acid, 327.3 parts of isophthalic acid, and 2 parts of titanium diisopropoxybistriethanolamine as a condensation catalyst were added, and the reaction was carried out at 200°C under a nitrogen stream for 3 hours while distilling off the water produced. The reaction was then carried out at 200°C for 6 hours under reduced pressure of 0.5 to 2.5 kPa. When the acid value (mgKOH / g) fell below 1, the reaction product was removed from the reaction vessel, yielding a polyester diol with a hydroxyl value (mgKOH / g) of 56.1. In a simple pressurized reaction apparatus equipped with a stirrer and a heating device, 45.1 parts of the above-mentioned polyester diol, 3.6 parts of 3-methyl-1,5-pentanediol, 7.5 parts of N-methyldiethanolamine as a polyol component having a tertiary amino group in the side chain, 36.9 parts of dicyclohexylmethane-4,4-diisocyanate (MDI-H) as a polyisocyanate component, and 100 parts of tetrahydrofuran as an organic solvent for the reaction were charged and stirred at 70°C for 12 hours to carry out the urethane formation reaction. Then, 6.9 parts of dimethyl sulfuric acid were charged and reacted at 50°C for 4 hours to produce a solvent solution of polyurethane resin (P-1) containing a quaternary ammonium salt and having an isocyanate group.

[0121] -Manufacturing Example 2- In a simple pressurized reaction apparatus equipped with a stirrer and a heating device, 45.1 parts of polycarbonate diol [Ethanol UH-200 manufactured by Ube Industries, Ltd.], 3.6 parts of 3-methyl-1,5-pentanediol, 7.5 parts of N-methyldiethanolamine as a polyol component having a tertiary amino group in the side chain, 36.9 parts of dicyclohexylmethane-4,4-diisocyanate (MDI-H) as a polyisocyanate component, and 100 parts of tetrahydrofuran as an organic solvent for the reaction were charged and stirred at 70°C for 12 hours to carry out the urethane formation reaction. Then, 6.9 parts of dimethyl sulfuric acid were charged and reacted at 50°C for 4 hours to produce a solvent solution of polyurethane resin (P-2) containing a quaternary ammonium salt and having an isocyanate group.

[0122] -Manufacturing Examples 3-12- Solvent solutions of polyurethane resins (P-3) to (P-12) were obtained in the same manner as in Production Example 2, except that the raw materials and quantities used were changed to those listed in Table 1.

[0123] -Manufacturing Example 13- In a container equipped with a stirrer, 30 parts of the solvent solution of polyurethane resin (P-4) obtained in Production Example 4 were added, and 84.4 parts of water were added while stirring at 200 rpm to disperse the mixture. 0.64 parts of isophorone diamine (IPDA), an extender, were added to the resulting dispersion under stirring, and the extension reaction was carried out for 30 minutes. Tetrahydrofuran was removed by distillation under reduced pressure at 60°C for 2 hours. Water was added to adjust the solid content concentration to 16.7% by weight to obtain a dispersion of polyurethane resin (P-13).

[0124] -Manufacturing Example 14- In a pressure-resistant reaction vessel equipped with a thermometer, heating / cooling device, stirrer, and dropping cylinder, 57 parts of myristyl alcohol and 0.08 parts of potassium hydroxide were added. After purging with nitrogen, the vessel was sealed and the temperature was raised to 140°C. Under stirring, 43 parts of ethylene oxide were added dropwise over 5 hours at 140°C, while adjusting the pressure to 0.5 MPa or less. The mixture was then aged at the same temperature for 3 hours to obtain a 4-mol adduct of myristyl alcohol to ethylene oxide (O-1).

[0125] -Manufacturing Example 15- In a reaction vessel similar to that used in Production Example 14, 36 parts of oleyl alcohol and 0.08 parts of potassium hydroxide were added, the vessel was purged with nitrogen, sealed, and heated to 140°C. Under stirring, 64 parts of ethylene oxide were added dropwise over 5 hours at 140°C, while adjusting the pressure to 0.5 MPa or less. The mixture was then aged at the same temperature for 3 hours to obtain an 11-mol adduct of oleyl alcohol to ethylene oxide (O-2).

[0126] -Manufacturing Example 16- In a reaction vessel similar to that used in Production Example 14, 15 parts of sorbitol and 0.08 parts of potassium hydroxide were added, the vessel was purged with nitrogen, sealed, and heated to 140°C. Under stirring, 85 parts of ethylene oxide were added dropwise over 5 hours at 140°C, while adjusting the pressure to 0.5 MPa or less. The mixture was then aged at the same temperature for 3 hours to obtain a 24-mol adduct of sorbitol to ethylene oxide (O-3).

[0127] -Manufacturing Example 17- In a reaction vessel equipped with a condenser, thermometer, stirrer, and nitrogen inlet tube, 39 parts sorbitol, 61 parts oleic acid, and 50 parts xylene as a solvent were added and reacted for 3 hours at 180°C under a nitrogen stream while distilling off the water produced. When the acid value (mgKOH / g) fell below 1, the reaction system was reduced to a reduced pressure, and the xylene was removed to obtain the sorbitol-oleic acid ester (O-4).

[0128] -Manufacturing Example 18- In a reaction vessel equipped with a condenser, thermometer, stirrer, and nitrogen inlet, 68 parts of polyoxyethylene monomethyl ether (Sigma-Aldrich, Mn=550), 32 parts of oleic acid, and 50 parts of xylene as a solvent were added and the mixture was reacted at 180°C under a nitrogen stream for 3 hours while distilling off the water produced. When the acid value (mgKOH / g) fell below 1, the reaction system was reduced to a reduced pressure, and the xylene was removed to obtain polyethylene glycol oleate (O-5).

[0129] -Manufacturing Example 19- In a reaction vessel equipped with a condenser, thermometer, stirrer, and nitrogen inlet tube, 44 parts of polyoxyethylene monomethyl ether (polyethylene glycol monomethyl ether 220, Mn=220, manufactured by Kanto Chemical Co., Ltd.), 56 parts of oleic acid, and 50 parts of xylene as a solvent were added and the reaction was carried out at 180°C under a nitrogen stream for 3 hours while distilling off the water produced. When the acid value (mgKOH / g) fell below 1, the reaction system was reduced to a reduced pressure, and the xylene was removed to obtain polyethylene glycol oleate ester (O-6).

[0130] -Comparative Manufacturing Examples 1-3- Solvent solutions of polyurethane resins (P'-1) to (P'-3) were obtained in the same manner as in Production Example 2, except that the raw materials and quantities used were changed to those listed in Table 1.

[0131] -Comparative Manufacturing Example 4- In a reaction vessel equipped with a condenser, thermometer, stirrer, and nitrogen inlet tube, 59 parts of polypropylene glycol-diglycidyl ether (epoxy equivalent 201 g / equivalent) were charged. The vessel was then purged with nitrogen, heated to 70°C, and 38 parts of di-n-butylamine were added dropwise using a dropping device. The reaction was then carried out at 90°C for 10 hours after the addition was complete. After the reaction, an infrared spectrophotometer was used to confirm the disappearance of the absorption peak around 842 cm⁻¹, which was attributed to the epoxy group in the reaction product, yielding a tertiary amino group-containing polyol. (Amine value and hydroxyl value were both 165.5 mg KOH / g) In a reaction vessel equipped with a condenser, thermometer, stirrer, and nitrogen inlet, 219.8 parts of 1,4-butanediol, 254.0 parts of neopentyl glycol, 362.0 parts of terephthalic acid, 318.6 parts of adipic acid, and 2 parts of titanium diisopropoxybistriethanolamine as a condensation catalyst were added and the mixture was reacted at 200°C under a nitrogen stream for 3 hours while distilling off the water produced. The reaction was then continued at 200°C for 6 hours under reduced pressure of 0.5 to 2.5 kPa. When the acid value (mgKOH / g) fell below 1, the reaction product was removed from the reaction vessel to obtain a polyester diol with a hydroxyl value (mgKOH / g) of 58.9. In a simple pressurized reaction apparatus equipped with a stirrer and a heating device, 48.6 parts of polycarbonate diol [Ethanol UH-200 manufactured by Ube Industries, Ltd.], 24.2 parts of the above polyester polyol (neopentyl glycol-1,4-butanediol-terephthalic acid-adipic acid copolymer), 5.8 parts of the above polyol having a tertiary amino group, 19.3 parts of dicyclohexylmethane-4,4-diisocyanate (MDI-H) as a polyisocyanate component, and 100 parts of ethyl acetate as an organic solvent for the reaction were charged and stirred at 70°C for 12 hours to carry out the urethane formation reaction. After the reaction, 3.2 parts of "Aminosilane A1100" (manufactured by Nippon Unicar Co., Ltd., γ-aminopropyltriethoxysilane) were added and the mixture was reacted for 1 hour to prepare an ethyl acetate solution of the urethane prepolymer. Next, 1.0 part of hydrazine hydrate was added to the urethane prepolymer solution, and the chain extension reaction was carried out for 1 hour. Next, 134.6 parts of ethyl acetate and 2.1 parts of dimethyl sulfuric acid were added, and the mixture was maintained at 50°C for 4 hours. Then, 227.3 parts of water were added while stirring at 200 rpm to disperse the mixture. The ethyl acetate was removed by distillation under reduced pressure at 60°C for 2 hours. Water was added to adjust the solid content concentration to 16.7% by weight to obtain a dispersion of polyurethane resin (P'-4).

[0132] Table 1 shows the composition and physical properties of the polyurethane resin.

[0133] [Table 1]

[0134] -Manufacturing example Q-1- In the vessel of a pigment disperser (TSU-6U, manufactured by AIMEX), 30 parts of the solvent solution of the polyurethane resin (P-1) prepared in Production Example 1 and 120 parts of tetrahydradofuran were added and stirred until the resin was uniformly dissolved. Next, 10 parts of cyanide pigment [BASF Heliogen Blue D7088] and 350 parts of glass beads [ASGB-320, manufactured by AS ONE] were added, and the mixture was dispersed for 4 hours while cooling water at 4°C was passed through the jacket. The obtained dispersion slurry was stirred at 200 rpm, and 100 parts of water were added to disperse the mixture. 0.64 parts of isophorone diamine (IPDA), an extender, were added to the resulting dispersion under stirring, and the extension reaction was carried out for 30 minutes. Tetrahydrofuran was removed by distillation under reduced pressure at 60°C for 2 hours, and the glass beads were removed by filtration. Water was added to adjust the solid content concentration to 25% by weight to obtain an aqueous pigment dispersion (Q-1).

[0135] -Manufacturing Examples Q-2~Q-25- Pigment aqueous dispersions (Q-2) to (Q-25) were obtained in the same manner as in manufacturing example Q-1, except that the raw materials and quantities used were changed to those listed in Table 2.

[0136] -Manufacturing example Q-26- In the vessel of a pigment disperser (TSU-6U, manufactured by AIMEX), 30 parts of a solvent solution of polyurethane resin (P-4) prepared in Production Example 4, 50 parts of tetrahydradofuran, and 0.5 parts of polyethylene glycol oleate ester (O-6) prepared in Production Example 19 were added, and the mixture was stirred until the resin was uniformly dissolved. 1.51 parts of isophorone diamine (IPDA), an extender, were added under stirring, and the extension reaction was carried out for 30 minutes. Next, 10 parts of cyanide pigment [BASF Heliogen Blue D7088] and 140 parts of glass beads [ASGB-320, manufactured by AS ONE] were added, and the mixture was dispersed for 3 hours while cooling water at 4°C was passed through the jacket. The resulting dispersion slurry was stirred at 200 rpm, and 100 parts of water were added to disperse the mixture. Tetrahydrofuran was removed by distillation under reduced pressure at 60°C for 2 hours, and the glass beads were removed by filtration. Water was added to adjust the solid content concentration to 25% by weight to obtain an aqueous pigment dispersion (Q-26).

[0137] -Manufacturing example Q-27- 90 parts of a dispersion of polyurethane resin (P-13) prepared in Production Example 13, 0.5 parts of polyethylene glycol oleate ester (O-6) prepared in Production Example 19, 10 parts of cyanide pigment [BASF Heliogen Blue D7088], and 140 parts of glass beads [ASGB-320, AS ONE] were added to the vessel of a pigment disperser (TSU-6U, manufactured by AIMEX). The mixture was then dispersed for 3 hours while cooling water at 4°C was passed through the jacket. The glass beads were then removed by filter, and water was added to adjust the solid content concentration to 25% by weight to obtain an aqueous pigment dispersion (Q-27).

[0138] -Comparative manufacturing examples Q-1~Q-3- Pigment aqueous dispersions (Q'-1) to (Q'-3) were obtained in the same manner as in Example 1, except that the raw materials and quantities used were changed to those listed in Table 2.

[0139] -Comparative manufacturing example Q-4- 90 parts of the polyurethane resin (P'-4) dispersion prepared in Comparative Production Example 4, 10 parts of cyanide pigment [BASF Heliogen Blue D7088], and 140 parts of glass beads [ASGB-320, AS ONE] were added to the vessel of a pigment disperser (TSU-6U, manufactured by AIMEX). The mixture was then dispersed for 3 hours while cooling water at 4°C was passed through the jacket. The glass beads were then removed by filter, and water was added to adjust the solid content concentration to 25% by weight to obtain an aqueous pigment dispersion (Q'-4).

[0140] Table 2 shows the proportions of the aqueous pigment dispersions obtained in each production example and comparative production example.

[0141] [Table 2-1]

[0142] [Table 2-2]

[0143] [Table 2-3]

[0144] [Table 2-4]

[0145] -Examples 1-29, Comparative Examples 1-6- Each material was mixed and stirred according to the composition shown in Table 3 below to obtain inks (I-1) to (I-29) and comparative inks (I'-1) to (I'-6). Specifically, each ink was prepared by uniformly mixing each material and removing insoluble matter using a filter.

[0146] [Table 3-1]

[0147] [Table 3-2]

[0148] [Table 3-3]

[0149] The various abbreviations in Table 3 are as follows: BYK348: Silicone-based surfactant "BYK-348" (product name, manufactured by BYK Chemie Japan Co., Ltd.) Olphine E1010: Acetylene-based surfactant "Olfine E1010" (product name, manufactured by Nisshin Chemical Industry Co., Ltd.) Glycerin: Standard boiling point 290°C BTG: Triethylene glycol butyl ether (standard boiling point 272°C)

[0150] -Evaluation Method- The following describes the measurement and evaluation methods for the obtained aqueous pigment dispersions.

[0151] -Evaluation of initial variance- The particle size of the aqueous pigment dispersion in the ink prepared as described above, and the ink viscosity were evaluated based on the measurement results. The particle size of the aqueous pigment dispersion in inks using color pigments (cyan, magenta, yellow, and black in the examples) was evaluated according to the following criteria. ○: Cumulant average diameter is 180 nm or less ×: Cumulant average diameter is greater than 180 nm The particle size of the aqueous pigment dispersion in ink using white pigment was evaluated according to the following criteria. ○: Cumulant average diameter is 300 nm or less ×: Cumulant average diameter is greater than 300 nm Ink viscosity was evaluated according to the following criteria. ○: Ink viscosity is 6.0 mPa·s or less ×: Ink viscosity is above 6.0 mPa·s Based on particle size and viscosity measurements, the initial dispersibility of the ink was evaluated according to the following criteria. ○: Both the average diameter of the cumulant and the ink viscosity are ○ ×: Either the average diameter of the cumulant, the ink viscosity, or both are incorrect. -Method for measuring particle size of aqueous pigment dispersions in ink- The particle size was measured using a light scattering particle size distribution analyzer [ELSZ-1000, manufactured by Otsuka Electronics Co., Ltd.], and the resulting cumulant average diameter was defined as the particle size.

[0152] -Method for measuring ink viscosity- The viscosity of inks (I-1) to (I-30) and the comparative inks (I'-1), (I'-2), and (I'-4) was measured using the following measuring device and conditions. Equipment: MCR102 (manufactured by Anton Paar) Jig: 75mm cone plate Shear rate: 1000 1 / s Measurement temperature: 20℃ Aggregated (I'-3) was excluded from the analysis.

[0153] -Evaluation of storage stability- Storage stability was evaluated by leaving the ink standing in a circulating air dryer set to 60°C for 5 days, and measuring the change in particle size of the aqueous pigment dispersion in the ink, as well as the change in ink viscosity, before and after the test. The method for calculating the rate of change is shown in the following formula. Percentage change in particle size of aqueous pigment dispersion in ink: (S2-S1) / S1 × 100 (%) Ink viscosity change rate: (V2 - V1) / V1 × 100 (%) S1: Particle size of the aqueous pigment dispersion in the ink before testing S2: Particle size of the aqueous pigment dispersion in the ink after testing V1: Ink viscosity before testing V2: Ink viscosity after testing The evaluation criteria are as follows: ○: The rate of change in particle size and ink viscosity is within 10%. ×: The change rate of particle size and / or ink viscosity is greater than 10%

[0154] -Method for evaluating dry abrasion fastness (abrasion resistance) of cotton fabrics: Color inks- Plain cotton broadcloth [100% cotton by mass] was printed with inks (I-1) to (I-14), (I-16) to (I-24), (I-26) to (I-27), and comparative inks (I'-1), (I'-2), and (I'-4) using a modified Seiko Epson PX-G930 inkjet printer. The printed samples were dried at 160°C for 10 minutes to create test pieces (21cm x 28cm) coated with pigment and polyurethane resin on the plain cotton broadcloth. Dry friction fastness was evaluated in accordance with JIS L0849-2. A load of 200g was applied for 100 back-and-forth rubs. The color transfer density on the No. 3 cloth side was measured at 9 points using a spectrophotometer [X-rite 938, X-Rite Corporation], and the average of the measurement results was used as the color transfer density. The color transfer density was evaluated according to the following criteria, and the results are shown in Table 3. A lower color transfer density indicates better friction fastness. ◎: Dye migration concentration 0.10 or less ○: Transfer concentration greater than 0.10 and 0.15 or less. △: Transfer staining concentration greater than 0.15 and less than or equal to 0.20 ×: Transfer concentration greater than 0.20 and less than or equal to 0.30 A transfer staining concentration of 0.15 or less is considered to be at a practical level.

[0155] -Method for evaluating dry abrasion fastness (abrasion resistance) of cotton fabrics: White ink- Plain black cotton broadcloth [100% black cotton by mass] was printed with inks (I-15) and (I-25) using a modified Seiko Epson inkjet printer PX-G930. The prints were then dried at 160°C for 10 minutes to create test pieces (21cm x 28cm) coated with pigment and polyurethane resin on the plain cotton broadcloth. Dry friction fastness was evaluated in accordance with JIS L0849-2. The surface was rubbed 100 times back and forth with a load of 200g. Nine points on the printed surface were measured using a spectrophotometer [X-rite 938, X-Rite Corporation] before and after rubbing, and the average of the difference between the pre- and post-rubbing measurements was used as ΔL. * ΔL * The following criteria were used to evaluate the ΔL, and the results are shown in Table 3. * The lower the value, the better the frictional fastness. ◎:ΔL * ≤0.3 〇:0.3<ΔL * ≤1.0 △: 1.0 < ΔL * ≤5.0 ×: 5.0 < ΔL *

[0156] -Method for evaluating wet abrasion fastness (abrasion resistance) of cotton fabrics: Color inks- Plain cotton broadcloth [100% cotton by mass] was printed with inks (I-1) to (I-14), (I-16) to (I-24), (I-26) to (I-27), and inks (I'-1), (I'-2), and (I'-4) using a modified Seiko Epson PX-G930 inkjet printer. The printed samples were dried at 160°C for 10 minutes to create test pieces (21cm x 28cm) coated with pigment and polyurethane resin on the plain cotton broadcloth. The color transfer density on the No. 3 cloth side was measured at 9 points using a spectrophotometer [X-rite 938, manufactured by X-Rite Corporation], and the average of the measurement results was taken as the color transfer density. The color transfer density was evaluated according to the following criteria, and the results are shown in Table 3. The lower the color transfer density, the better the abrasion fastness. ◎: Dye migration concentration 0.20 or less ○: Transfer concentration greater than 0.20 and 0.25 or less. △: Transfer staining concentration greater than 0.25 and less than or equal to 0.30 ×: Transfer concentration greater than 0.30 and less than or equal to 0.40 A transfer staining concentration of 0.25 or less is considered to be at a practical level.

[0157] -Method for evaluating wet abrasion fastness (abrasion resistance) of cotton fabrics: White ink- Plain black cotton broadcloth [100% black cotton by mass] was printed with inks (I-15) and (I-25) using a modified Seiko Epson PX-G930 inkjet printer. The prints were then dried at 160°C for 10 minutes to create test pieces (21cm x 28cm) coated with pigment and polyurethane resin on the plain cotton broadcloth. The printed surface before and after abrasion was measured at 9 points using a spectrophotometer [X-rite 938, manufactured by X-Rite Corporation], and the average value of the difference between the measurement results before and after abrasion was calculated as ΔL. * ΔL * The following criteria were used to evaluate the ΔL, and the results are shown in Table 3. * The lower the value, the better the frictional fastness. ◎:ΔL * ≤0.3 〇:0.3<ΔL * ≤1.0 △: 1.0 < ΔL * ≤5.0 ×: 5.0 < ΔL *

[0158] -Method for evaluating color development on cotton fabric: Color inks- Plain cotton broadcloth [100% cotton by mass] was printed with inks (I-1) to (I-14), (I-16) to (I-24), (I-26) to (I-27), and comparative inks (I'-1), (I'-2), and (I'-4) using a modified Seiko Epson PX-G930 inkjet printer. The printed samples were dried at 160°C for 10 minutes to create test pieces (21cm x 28cm) coated with pigment and polyurethane resin on the plain cotton broadcloth. Image density was measured at 9 points using a spectrophotometer [X-rite 938, manufactured by X-Rite Corporation], and the average of the measurement results was defined as the image density. The image density was evaluated according to the following criteria, and the results are shown in Table 3. Higher image density indicates better color reproduction. ○: Image density 1.3 or higher △: Image density between 1.2 and less than 1.3 ×: Image density less than 1.2 An image density of 1.3 or higher is considered practical.

[0159] -Method for evaluating color development on cotton fabric: White ink- Plain black cotton broadcloth [100% black cotton by mass] was printed with inks (I-15) and (I-25) using a modified Seiko Epson PX-G930 inkjet printer. The prints were then dried at 160°C for 10 minutes to create test pieces (21cm x 28cm) coated with pigment and polyurethane resin on the plain cotton broadcloth. Image density L * The judgment will be based on the value, L * Nine points were measured using a spectrophotometer [X-rite 938 manufactured by X-Rite Corporation], and the average value of the measurement results was adopted. * The following criteria were used to evaluate the L, and the results are shown in Table 3. * The higher the value, the better the color development. 〇:L * 70 or more △:L * 50 or more but less than 70 ×:L * less than 50

[0160] -Filtration properties after heating- To assess the filtration properties after heating, the ink was left to stand for 5 days in a circulating dryer set to 60°C, and then vacuum filtration was performed using a water aspirator (maximum vacuum: approximately 24 mmHg). The filters used were a pre-filter (φ47mm, 100 sheets, AP2504700 / 2-3055-07) and an MF-Millipore membrane (cellulose mixed ester, hydrophilic, 8.0μm, 47mm, white). Evaluation was performed based on the amount of ink that could pass through. The evaluation criteria were as follows. The results are shown in Table 3. ◎:300g or more ○: 100g or more, less than 300g △: 50g or more but less than 100g ×: Less than 50g

[0161] -Continuous Printability Test- The ink produced as described above was installed in a modified Seiko Epson PX-G930 inkjet printer. Solid images were continuously printed at a resolution of 1440*720 dpi, and the presence of surface irregularities was evaluated. The evaluation criteria were as follows. The results are shown in Table 3. ◎: No Sujimura occurrences for more than 24 hours. ○: Sujimura occurs between 5 hours and 24 hours later. △: Sujimura occurs between 1 hour and 5 hours. ×: Sujimura occurred in less than 1 hour.

[0162] Inks (I-1) to (I-30) exhibit excellent initial dispersibility, storage stability, and abrasion resistance. They also show excellent color development on untreated cotton fabrics. Comparative inks (I'-1) and (I'-2) that did not use quaternary ammonium compounds showed insufficient color development (Comparative Examples 1 and 2). Comparative ink (I'-3) that did not use quaternary ammonium compounds exhibited particle aggregation under basic conditions, resulting in insufficient initial dispersibility and storage stability (Comparative Example 3). Comparative ink (I'-4), which contained 7.9 parts of quaternary ammonium compound in the polyurethane resin, showed insufficient initial dispersibility and storage stability, as well as insufficient color development (Comparative Example 4).

Claims

1. An aqueous inkjet ink comprising a pigment aqueous dispersion, water, and a water-soluble organic solvent, The aforementioned aqueous pigment dispersion contains a pigment dispersed in a polyurethane resin obtained by reacting an active hydrogen atom-containing component (A) with an organic polyisocyanate component (B). The active hydrogen atom-containing component (A) contains a quaternary ammonium compound (a1) and a crystalline polycarbonate polyol. The organic polyisocyanate component (B) contains one or more selected from the group consisting of linear or branched aliphatic polyisocyanates (b1), alicyclic polyisocyanates (b2), and aromatic polyisocyanates (b3). A water-based inkjet ink in which the weight percentage of the quaternary ammonium compound (a1) is 12% by weight or more, based on the total weight of the active hydrogen atom-containing component (A) and the organic polyisocyanate component (B).

2. The aqueous inkjet ink according to claim 1, wherein the quaternary ammonium compound (a1) is a compound represented by the following general formula (1) and / or a compound represented by the following general formula (2). 【Chemistry 1】 [In general formula (1), R 1 and R 2 Each of these is an alkyl group having 1 to 24 carbon atoms, and R 3 and R 4 Each is independently an alkylene group having 1 to 20 carbon atoms or an oxyalkylene group having 2 to 20 carbon atoms, X - It is an anion. 【Chemistry 2】 [In General Formula (2), R 5 , R 6 and R 7 are each independently an alkyl group having 1 to 4 carbon atoms, and X - is an anion.]

3. The aqueous inkjet ink according to claim 1 or 2, wherein the active hydrogen atom-containing component (A) contains one or more selected from the group consisting of polyester polyols and polyether polyols.

4. The aqueous inkjet ink according to any one of claims 1 to 3, wherein the water-soluble organic solvent contains a water-soluble organic solvent with a standard boiling point of 180°C or higher.

5. An aqueous inkjet ink according to any one of claims 1 to 4, further comprising a surfactant.

6. The aqueous inkjet ink according to claim 5, wherein the surfactant contains a nonionic surfactant.

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