Pigment aqueous dispersion

Abstract

To provide a pigment aqueous dispersion which is excellent in initial dispersibility and storage stability, and is excellent in color development property, especially, for a fabric that is not subjected to pre-treatment.SOLUTION: A pigment aqueous dispersion for aqueous inkjet ink contains a pigment dispersed with a polyurethane resin obtained through the reaction of an active hydrogen atom-containing component (A) with an organic polyisocyanate component (B), and an aqueous medium, wherein the active hydrogen atom-containing component (A) contains a quaternary ammonium compound (a1), 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] The present invention relates to an aqueous pigment dispersion. [Background technology]

[0002] Conventional methods for dispersing pigments in aqueous media in the field of inkjet printing include a method using a surfactant, a method of modifying the pigment surface with a hydrophilic group, and a method of dispersing pigments in a hydrophilic resin. Among these, the method of dispersing pigments in hydrophilic resins has been studied because of its high dispersion stability and the ability to impart scratch resistance to the aqueous pigment dispersion itself. For example, there is an aqueous pigment dispersion in which a pigment is dispersed in a polyurethane resin containing an anionic group (Patent Document 1). Furthermore, in recent years, pigment printing has been expected to be used in the inkjet field, where drop-on-demand printing is possible. In pigment printing, in order to ensure a practically minimum level of image color development (image density), the fabric is pretreated with inorganic metal salts, cationic resins, etc., and printing is performed on the pretreated fabric, but sufficient color development cannot be obtained with fabrics that have not been pretreated, and there is a problem that the fabrics that can be used are limited. The pigment dispersion obtained in Patent Document 1 can provide excellent image density when the recording medium is paper, but the color development of the printed matter is still insufficient. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-114991 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide an aqueous pigment dispersion that is excellent in initial dispersion stability and storage stability, and that exhibits excellent color development, particularly on fabrics that have not been pretreated. [Means for solving the problem]

[0005] The present inventors have conducted extensive research and have arrived at the present invention, which relates to an aqueous pigment dispersion for use in aqueous inkjet inks, comprising an aqueous medium and a pigment dispersed in a polyurethane resin obtained by reacting an active hydrogen atom-containing component (A) with an organic polyisocyanate component (B), wherein the active hydrogen atom-containing component (A) contains a quaternary ammonium compound (a1), and the weight proportion 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). [Effects of the Invention]

[0006] The present invention makes it possible to provide an aqueous pigment dispersion that is excellent in initial dispersion stability and storage stability, and that exhibits excellent color development, particularly on fabrics that have not been pretreated. DETAILED DESCRIPTION OF THE INVENTION

[0007] The aqueous pigment dispersion of the present invention is an aqueous pigment dispersion for use in an aqueous inkjet ink, which contains a pigment dispersed in a polyurethane resin obtained by reacting an active hydrogen atom-containing component (A) with an organic polyisocyanate component (B), and an aqueous medium, The active hydrogen atom-containing component (A) contains a quaternary ammonium compound (a1), and the weight proportion 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 the polyurethane resin used in the aqueous pigment dispersion of the present invention, the active hydrogen atom-containing component (A) contains a quaternary ammonium compound (a1). By including the quaternary ammonium compound (a1), the aqueous pigment dispersion particles are unevenly distributed on the surface of 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, since the quaternary ammonium compound is ionized by covalently bonding an alkyl group to the nitrogen atom, it remains in an ionized state even when the counter ion is lost. In other words, the aqueous pigment dispersion of the present invention is stable even in an environment with a pH of 7 or higher, and can be used as an inkjet ink.

[0009] Quaternary ammonium compound (a1) is NR4 + and is not particularly limited as long as it is a compound containing an active hydrogen atom, but examples thereof include a reaction product of an active hydrogen atom-containing component containing a tertiary amino group and a quaternizing agent (a1-2).

[0010] Examples of the active hydrogen atom-containing component containing a tertiary amino group include a tertiary amino group-containing polyol (a1-1), a tertiary amino group-containing polycarboxylic acid, a tertiary amino group-containing polyamine, a tertiary amino group-containing polyamide, a tertiary amino group-containing polyurethane compound, and a tertiary amino group-containing polyurea compound.

[0011] Examples of the tertiary amino group-containing polyol (a1-1) include compounds represented by the following general formula (3) and / or the following general formula (4). [ka] [In general formula (3), R 8 is an alkyl group having 1 to 24 carbon atoms, and R 9 and R 10 are each 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 are each independently an alkyl group having 1 to 4 carbon atoms.

[0012] Among the tertiary amino group-containing polyols (a1-1), the compounds represented by the general formula (3) include N-alkyl dialcohol amines and polyoxyalkylene alkyl amines.

[0013] In the present invention, "alkyl" includes linear and branched alkyl groups. It is preferably a linear or branched alkyl group having 1 to 24 carbon atoms, more preferably a linear or branched alkyl group having 1 to 12 carbon atoms, and even more preferably a linear or branched alkyl group having 1 to 4 carbon atoms. Examples of the alkyl group include, in particular, the following: methyl, ethyl, propyl, isopropyl, n-butyl, 2-(iso-)butyl, sec-butyl, tert-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, 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.

[0014] Specific examples of N-alkyl dialcohol amines and polyoxyalkylene alkyl amines include N-methyl diethanolamine, N-ethyl diethanolamine, N-butyl diethanolamine, N-tert-butyl diethanolamine, N-lauryl diethanolamine, N-stearyl diethanolamine, and poly(n=1 to 10)oxyethylene oleylamine.

[0015] Among the tertiary amino group-containing polyols (a1-1), the compound represented by the general formula (4) includes 3-(diethylamine)-1,2-propanediol.

[0016] The tertiary amino group-containing polycarboxylic acid is not particularly limited, but examples thereof include a product having a terminal carboxylic acid group obtained by esterification of the above-mentioned tertiary amino group-containing polyol (a1-1) with a polycarboxylic acid.Specific examples include a product having a terminal carboxylic acid group obtained by dehydration condensation of an N-alkyldialcoholamine with an aliphatic or aromatic dicarboxylic acid in a molar ratio of functional groups of 1:2.Examples include a reaction product of N-methyldiethanolamine with succinic acid and a reaction product of N-methyldiethanolamine with terephthalic acid.

[0017] The tertiary amino group-containing polyamine is not particularly limited, but examples thereof include a product having an amino group terminal obtained by amidation reaction of the above-mentioned tertiary amino group-containing polycarboxylic acid with a polyamine, a product obtained by urethanization reaction of the above-mentioned tertiary amino group-containing polyol (a1-1) with an organic polyisocyanate to obtain an isocyanate-terminated product, to which water is added to convert the terminal into an amino group, and a product obtained by adding a polyamine to the above-mentioned isocyanate-terminated product to convert the terminal into an amino group.Specific examples include a product having an amino group terminal obtained by dehydration condensation of an N-alkyldialcoholamine with an aliphatic or aromatic dicarboxylic acid in a molar ratio of functional groups (hydroxyl group:carboxylic acid group) of 1:2 to obtain a product having a carboxylic acid terminal, and then dehydration condensation of a polyamine in a molar ratio of functional groups (carboxylic acid group:amino group) of 1:2 to obtain a product having a carboxylic acid terminal. Other examples include a reaction product in which a terminal isocyanate group product is obtained by urethane-forming a polyisocyanate with an N-alkyl dialcohol amine and an aliphatic, alicyclic, or aromatic diisocyanate in a molar ratio of functional groups (hydroxyl group:isocyanate group) of 1:2, and the terminal is converted to an amino group with water, and a terminal amino group product obtained by dehydrating and condensing the terminal isocyanate group product with a polyamine in a molar ratio of functional groups (isocyanate group:amino group) of 1:2. More specific examples include a terminal amino group product obtained by dehydrating and condensing N-methyldiethanolamine, succinic acid, and isophorone diamine, a terminal amino group product obtained by reacting N-methyldiethanolamine, isophorone diisocyanate, and water, and a terminal amino group product obtained by reacting N-methyldiethanolamine, isophorone diisocyanate, and isophorone diamine.

[0018] The tertiary amino group-containing polyamide is not particularly limited, but examples thereof include a terminal amide group product obtained by the reaction of the above-mentioned tertiary amino group-containing polycarboxylic acid with ammonia. Specifically, examples thereof include a terminal amide group product obtained by dehydrating and condensing an N-alkyldialcoholamine with an aliphatic or aromatic dicarboxylic acid at a functional group molar ratio (hydroxyl group:carboxylic acid group) of 1:2 to obtain a terminal carboxylic acid group product, and then dehydrating and condensing ammonia at a functional group molar ratio (carboxylic acid group:ammonia) of 1:1 to obtain a terminal amide group product. Specifically, examples thereof include a terminal amide group reaction product obtained by dehydrating and condensing ammonia to a reaction product of N-methyldiethanolamine and succinic acid.

[0019] The reaction between a tertiary amino group-containing polycarboxylic acid and ammonia can be exemplified by the following [1] and [2]. [1] Adding a tertiary amino group-containing polycarboxylic acid to ammonia and dehydrating the resulting ammonium salt to produce a tertiary amino group-containing polyamide. [2] Add tertiary amino group-containing polycarboxylic acid and ammonia to produce tertiary amino group-containing polyamide and alcohol by transesterification.

[0020] The tertiary amino group-containing polyurethane compound is not particularly limited, but examples thereof include a product obtained by urethane reaction of the above-mentioned tertiary amino group-containing polyol (a1-1) with an organic monoisocyanate in a molar ratio of hydroxyl groups to isocyanate groups of 1:1. Specific examples include a urethane group-containing product obtained by reaction of an N-alkyl dialcohol amine with an aliphatic, alicyclic, or aromatic monoisocyanate in a molar ratio of functional groups of 1:1. More specific examples include a reaction product of N-methyldiethanolamine with phenylisocyanate.

[0021] Examples of tertiary amino group-containing polyurea compounds include, but are not limited to, products containing urea groups obtained by adding ammonia or an organic monoamine to the isocyanate-terminated product obtained by urethane-forming a tertiary amino group-containing polyol (a1-1) with an organic polyisocyanate. Specific examples include urea group-containing products obtained by urethane-forming a terminal isocyanate group product obtained by urethane-forming a N-alkyl dialcoholamine with an aliphatic, alicyclic, or aromatic diisocyanate in a functional group molar ratio (hydroxyl group:isocyanate group) of 1:2, and then reacting the resulting product with ammonia or a monoamine in a functional group molar ratio (isocyanate group:ammonia or amino group) of 1:1. More specific examples include products obtained by reacting N-methyldiethanolamine and isophorone diisocyanate with piperidine to obtain a terminal isocyanate group product.

[0022] Examples of the quaternizing agent (a1-2) include alkyl halide compounds, dialkyl sulfate compounds, trialkyl phosphate compounds, etc. Specific examples include ethyl bromide, ethyl iodide, dimethyl sulfate, diethyl sulfate, dipropyl sulfate, dibutyl sulfate, trimethyl phosphate, etc. Among these, dimethyl sulfate and diethyl sulfate are preferred from the viewpoint of reaction rate.

[0023] The quaternary ammonium compound (a1) in the present invention is preferably a compound represented by the following general formula (1) and / or the following general formula (2). [ka] [In general formula (1), R 1 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.] [ka] [In general formula (2), R 5 ~R7 are each independently an alkyl group having 1 to 4 carbon atoms, and X - is an anion.]

[0024] The quaternary ammonium compound (a1) in the present invention is preferably a product obtained by reacting a tertiary amino group-containing polyol (a1-1) represented by general formula (3) and / or general formula (4) with a quaternizing agent (a1-2) in a molar ratio of the compounds of 1:1.

[0025] Specific examples of the quaternary ammonium compound (a1) represented by general formula (1) include a reaction product of N-methyldiethanolamine with any one of ethyl bromide, ethyl iodide, dimethyl sulfate, diethyl sulfate, dipropyl sulfate, dibutyl sulfate, and trimethyl phosphate; a reaction product of N-ethyldiethanolamine with any one of ethyl bromide, ethyl iodide, dimethyl sulfate, diethyl sulfate, dipropyl sulfate, dibutyl sulfate, and trimethyl phosphate; a reaction product of N-butyldiethanolamine with any one of ethyl bromide, ethyl iodide, dimethyl sulfate, diethyl sulfate, dipropyl sulfate, dibutyl sulfate, and trimethyl phosphate; and a reaction product of N-tert-butyldiethanolamine with ethyl bromide, ethyl iodide, and sulfate. reaction products of N-lauryldiethanolamine and any of ethyl bromide, ethyl iodide, dimethyl sulfate, diethyl sulfate, dipropyl sulfate, dibutyl sulfate, and trimethyl phosphate; reaction products of N-stearyldiethanolamine and any of ethyl bromide, ethyl iodide, dimethyl sulfate, diethyl sulfate, dipropyl sulfate, dibutyl sulfate, and trimethyl phosphate; reaction products of poly(n=1 to 10)oxyethyleneoleylamine and any of ethyl bromide, ethyl iodide, dimethyl sulfate, diethyl sulfate, dipropyl sulfate, dibutyl sulfate, and trimethyl phosphate. Among these, from the viewpoint of the amount of nitrogen atoms relative to the weight of the quaternary ammonium compound (a1) (from the viewpoint of hydrophilicity), N-methyldiethanolamine, N-ethyldiethanolamine, N-butyldiethanolamine, N-tert-butyldiethanolamine, N-lauryldiethanolamine, N-stearyldiethanolamine, and reaction products of poly(n=1 to 10)oxyethyleneoleylamine with dimethyl sulfate or diethyl sulfate are preferred, reaction products of N-methyldiethanolamine or N-ethyldiethanolamine with dimethyl sulfate or diethyl sulfate are more preferred, and reaction products of N-methyldiethanolamine with dimethyl sulfate or diethyl sulfate are even more preferred. The anion in the quaternary ammonium compound (a1) (the anion X in the general formulas (1) and (2)) - ) is an anion derived from the quaternizing agent (a1-2). The anion is a bromide ion (Br - ), iodide ion (I - ), methyl sulfate ion (CH3OSO3 - ), ethyl sulfate ion (C2H5OSO3 - ), propyl sulfate ion (C3H7OSO3 - ), butyl sulfate ion (C4H9OSO3 - ), dimethyl phosphate ion ((CH3O)2PO2 - ) are listed.

[0026] Specific examples of the quaternary ammonium compound (a1) represented by general formula (2) include reaction products of 3-(diethylamine)-1,2-propanediol with any one of ethyl bromide, ethyl iodide, dimethyl sulfate, diethyl sulfate, dipropyl sulfate, dibutyl sulfate, and trimethyl phosphate. Among these, from the viewpoint of the amount of nitrogen atoms relative to the weight of the quaternary ammonium compound (a1) (from the viewpoint of hydrophilicity), the reaction product of 3-(diethylamine)-1,2-propanediol with dimethyl sulfate or diethyl sulfate is preferred.

[0027] In one embodiment, the weight proportion of the quaternary ammonium compound (a1) in the polyurethane resin of the present invention is 12% by weight or more, preferably 12 to 60% by weight, more preferably 12 to 50% by weight, and even more preferably 12 to 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 proportion of the quaternary ammonium compound (a1) is less than 12% by weight, the pigment aqueous dispersion particles become coarse and the initial dispersibility deteriorates.

[0028] The active hydrogen atom-containing component (A) may contain a polyol 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 polycarbonate polyols, polyester polyols, and polyether polyols, more preferably polycarbonate polyols, and particularly preferably the polycarbonate polyol is a crystalline polycarbonate polyol.

[0029] Examples of polycarbonate polyols include polycarbonate polyols 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 having an alkyl group of 1 to 10 carbon atoms, an alkylene carbonate having an alkylene group of 2 to 6 carbon atoms, and a diaryl carbonate having an aryl group of 6 to 9 carbon atoms) while causing a dealcoholization reaction. Two or more types of low-molecular-weight dihydric alcohols and two or more types of low-molecular-weight carbonate compounds may be used in combination. The low-molecular-weight dihydric alcohol may contain a trihydric or higher alcohol.

[0030] Specific examples of polycarbonate polyols include aliphatic polycarbonate polyols 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 (e.g., a diol obtained by condensing 1,4-butanediol and 1,6-hexanediol with a dialkyl carbonate while causing a dealcoholization reaction). Specific examples of alicyclic polycarbonate polyols include polycyclohexamethylene carbonate diol and polynorbornene carbonate diol. Specific examples of aromatic polycarbonate polyols include poly1,4-xylylene carbonate diol, bisphenol A polycarbonate diol, and bisphenol F polycarbonate diol.

[0031] Commercially available polycarbonate polyols include Ethanocol UH-200 [polyhexamethylene carbonate diol with Mn=2,000, manufactured by Ube Industries, Ltd.], Ethanocol UH-100 [polyhexamethylene carbonate diol with Mn=1,000, manufactured by Ube Industries, Ltd.], Ethanocol UC-100 [polycyclohexamethylene carbonate diol with Mn=1,000, manufactured by Ube Industries, Ltd.], and Benebimi. Examples include All NL2010DB [polydecamethylene carbonate diol with Mn=2,000, manufactured by Mitsubishi Chemical Corporation], Duranol T5651 [polypentamethylene, hexamethylene carbonate diol with Mn=1,000, manufactured by Asahi Kasei Chemicals Corporation], and Duranol G4672 [polytetramethylene, hexamethylene carbonate diol with Mn=1,000, manufactured by Asahi Kasei Chemicals Corporation].

[0032] In one embodiment, the polycarbonate polyol is more preferably a crystalline polycarbonate polyol.

[0033] In the present invention, crystalline means that when the transition temperature of a sample is measured using a differential scanning calorimeter (DSC) according to the method described in JIS K7121, a peak top temperature of the endothermic peak is present. The conditions for measuring the peak top temperature of the endothermic peak are described below. Measurement is performed using a differential scanning calorimeter (e.g., Q2000 manufactured by TA Instruments). The sample is first heated from 20°C to 150°C at 10°C / min, then cooled from 150°C to 0°C at 10°C / min, and then heated a second time from 0°C to 150°C at 10°C / min. The temperature showing the top of the endothermic peak during the second heating process is taken as the peak top temperature of the endothermic peak.

[0034] When the polyurethane resin contains a polyol component containing a crystalline polycarbonate polyol as a constituent monomer (constituent unit), the mechanical strength can be improved, and therefore the abrasion resistance can be improved.

[0035] Examples of crystalline polycarbonate polyols include polycarbonate polyols produced by condensing saturated low-molecular-weight aliphatic or alicyclic dihydric alcohols with low-molecular-weight carbonate compounds (for example, dialkyl carbonates in which the alkyl group has 1 to 10 carbon atoms, alkylene carbonates in which the alkylene group has 2 to 6 carbon atoms, and diaryl carbonates in which the aryl group has 6 to 9 carbon atoms) while causing a dealcoholization reaction. Two or more types of low-molecular-weight dihydric alcohols and two or more types of low-molecular-weight carbonate compounds may be used in combination, but from the viewpoint of crystallinity, the content of one type of alcohol raw material is preferably 70 to 100% by weight, more preferably 100% by weight.

[0036] Specific examples of the crystalline polycarbonate polyol include polyhexamethylene carbonate diol, polydecamethylene carbonate diol, and polycyclohexamethylene carbonate diol.

[0037] Examples of polyester polyols include condensation type polyester polyols, polylactone polyols, and castor oil-based polyols.

[0038] The condensation type polyester polyol is a polyester polyol of a low molecular weight dihydric alcohol having a number average molecular weight (Mn) of less than 300 and a dicarboxylic acid having 2 to 10 carbon atoms or an ester-forming derivative thereof.

[0039] As the low molecular weight dihydric alcohol, a dihydric aliphatic dihydric alcohol having an Mn of less than 300 and a low molar adduct of an alkylene oxide (hereinafter sometimes abbreviated as AO) of a dihydric phenol having an Mn of less than 300 can be used. Examples of AO 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. Among the low molecular weight dihydric alcohols that can be used for the condensation type polyester polyol, preferred are ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexane glycol, 1,9-nonanediol, 1,10-decanediol, low molar EO or PO adducts of bisphenol A, and combinations thereof. Constituent components of the condensation type polyester polyol may include a trivalent or higher alcohol and a trivalent or higher carboxylic acid or an ester-forming derivative thereof.

[0040] Examples of dicarboxylic acids having 2 to 10 carbon atoms or their ester-forming derivatives that can be used in condensation polyester polyols include aliphatic dicarboxylic acids (succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, fumaric acid, maleic acid, etc.), alicyclic dicarboxylic acids (dimer acid, etc.), aromatic dicarboxylic acids (terephthalic acid, isophthalic acid, phthalic acid, etc.), anhydrides thereof (succinic anhydride, maleic anhydride, phthalic anhydride, etc.), acid halides thereof (adipic acid dichloride, etc.), low-molecular-weight alkyl esters thereof (dimethyl succinate, dimethyl phthalate, etc.), and combinations thereof. Examples of trivalent or higher polycarboxylic acids include trimellitic acid and pyromellitic acid.

[0041] Specific examples of condensation 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.

[0042] Commercially available condensation polyester polyols include Sun-Ester 2610 [polyethylene adipate diol with Mn=1,000, manufactured by Sanyo Chemical Industries, Ltd.], Sun-Ester 4620 [polytetramethylene adipate diol with Mn=2,000, manufactured by Sanyo Chemical Industries, Ltd.], Sun-Ester 2620 [polyethylene adipate diol with Mn=2,000, manufactured by Sanyo Chemical Industries, Ltd.], and Kuraray Polyol P-2010 [poly-3-methyl-1,5-pentane adipate diol with Mn=2,000, manufactured by Sanyo Chemical Industries, Ltd.]. ], Kuraray Polyol P-3010 [poly-3-methyl-1,5-pentane adipate diol with Mn=3,000], Kuraray Polyol P-6010 [poly-3-methyl-1,5-pentane adipate diol with Mn=6,000], Kuraray Polyol P-2020 [poly-3-methyl-1,5-pentane terephthalate diol with Mn=2,000], Kuraray Polyol P-2030 [poly-3-methyl-1,5-pentane isophthalate diol with Mn=2,000], and the like.

[0043] Examples of polylactone polyols include polylactone diol, polycaprolactone diol, polyvalerolactone diol, and polycaprolactone triol. Polylactone diols are polyaddition products of lactones to the above-mentioned low-molecular-weight dihydric alcohols, and examples of lactones include lactones having 4 to 12 carbon atoms (for example, γ-butyrolactone, γ-valerolactone, and ε-caprolactone).

[0044] Castor oil-based polyols include castor oil and modified castor oil modified with a polyol or AO. Modified castor oil can be produced by transesterification of castor oil with a polyol and / or AO addition. Examples of castor oil-based polyols include castor oil, trimethylolpropane-modified castor oil, pentaerythritol-modified castor oil, and castor oil-EO (4 to 30 mol) adducts.

[0045] The polyether polyols include aliphatic polyether polyols and aromatic ring-containing polyether polyols.

[0046] Examples of aliphatic polyether polyols include polyoxyethylene polyols [polyethylene glycol (hereinafter abbreviated as PEG)], polyoxypropylene polyols [polypropylene glycol], polyoxyethylene / propylene polyols, and polytetramethylene ether glycol.

[0047] Commercially available aliphatic polyether polyols include Sannix PP-600 (polyoxypropylene glycol, Mn=600, manufactured by Sanyo Chemical Industries, Ltd.), PTMG1000 (polytetramethylene ether glycol, Mn=1,000, manufactured by Mitsubishi Chemical Corporation), PTMG2000 (polytetramethylene ether glycol, Mn=2,000, manufactured by Mitsubishi Chemical Corporation), PTMG3000 (polytetramethylene ether glycol, Mn=3,000, manufactured by Mitsubishi Chemical Corporation), PTGL3000 (modified PTMG, Mn=3,000, manufactured by Hodogaya Chemical Co., Ltd.), and Sannix GP-3000 (polypropylene ether triol, Mn=3,000, manufactured by Sanyo Chemical Industries, Ltd.).

[0048] Examples of aromatic ring-containing polyether polyols 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, and 5-mol PO adduct of bisphenol A), as well as EO or PO adducts of resorcinol.

[0049] Examples of low-molecular-weight polyols include the above-mentioned aliphatic diols having 2 to 20 carbon atoms. Preferably, diols having a branched structure having 4 to 10 carbon atoms are used. More preferably, 3-methyl-1,5-pentanediol or neopentyl glycol is used. Furthermore, 3-methyl-1,5-pentanediol is even more preferred. The use of a low-molecular-weight polyol having a branched structure reduces the cohesive force between hard segments (urethane bond sites) in the polyurethane resin, improving solvent solubility and coating film flexibility, and providing excellent initial dispersibility (particularly reduced 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 wt %, more preferably 0.3 to 2 wt %, based on the total weight of the active hydrogen atom-containing component (A) and the organic polyisocyanate component (B).

[0050] Of the polyols other than the quaternary ammonium compound (a1), the active hydrogen atom-containing component (A) preferably contains at least one selected from polycarbonate polyols, polyester polyols, and polyether polyols, more preferably polycarbonate polyols, and particularly preferably the polycarbonate polyol is a crystalline polycarbonate polyol.

[0051] Examples of the organic polyisocyanate component (B) used in the polyurethane resin include aliphatic polyisocyanates having 2 to 18 carbon atoms (excluding carbon atoms in the isocyanate groups, the same applies hereinafter) and two or more isocyanate groups, alicyclic polyisocyanates having 4 to 15 carbon atoms, aromatic polyisocyanates having 6 to 20 carbon atoms, araliphatic polyisocyanates having 8 to 15 carbon atoms, and derivatives of these polyisocyanates (for example, isocyanurates). The polyisocyanate component may be used alone or in combination of two or more kinds.

[0052] Examples of the aliphatic polyisocyanate 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.

[0053] Examples of the alicyclic polyisocyanate 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.

[0054] Examples of aromatic polyisocyanates having 6 to 20 carbon atoms include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate (TDI), 4,4'- or 2,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate, 4,4',4''-triphenylmethane triisocyanate, m- or p-isocyanatophenylsulfonyl isocyanate, and crude MDI.

[0055] Examples of the aromatic aliphatic polyisocyanate having 8 to 15 carbon atoms include m- or p-xylylene diisocyanate (XDI), and α,α,α',α'-tetramethylxylylene diisocyanate (TMXDI).

[0056] From the viewpoint of the 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 and an alicyclic polyisocyanate having 4 to 15 carbon atoms, and more preferably TDI, IPDI, and hydrogenated MDI.

[0057] The equivalent ratio (NCO / OH) of the isocyanate groups contained in the organic polyisocyanate component (B) to the hydroxyl groups contained in the active hydrogen atom-containing component (A) is preferably 1.2 to 1.8, more preferably 1.3 to 1.6, from the viewpoints of uniform composition distribution and mechanical strength of the polyurethane resin.

[0058] The polyurethane resin has the above-mentioned active hydrogen atom-containing component (A) and organic polyisocyanate component (B) as essential constituent monomers (constituent units), but may contain compounds other than the active hydrogen atom-containing component (A) and the organic polyisocyanate component (B) as constituent monomers. Examples of constituent monomers other than the active hydrogen atom-containing component (A) and the organic polyisocyanate component (B) include chain extenders and reaction terminators. These may be used alone or in combination of two or more. In one aspect, the polyurethane resin is preferably a reaction product of a urethane prepolymer having an isocyanate group at its terminal, which is obtained by reacting the above-mentioned active hydrogen atom-containing component (A) with the organic polyisocyanate component (B), and a chain extender.

[0059] It is preferable to use a chain extender for the polyurethane resin. Examples of the chain extender include water, diamines having 2 to 10 carbon atoms (e.g., ethylenediamine, propylenediamine, hexamethylenediamine, isophoronediamine, toluenediamine, and piperazine), polyalkylenepolyamines having 2 to 10 carbon atoms (e.g., diethylenetriamine, triethylenetetramine, and tetraethylenepentamine), hydrazine or a derivative thereof (dibasic acid dihydrazide, e.g., adipic acid dihydrazide), polyepoxy compounds having 2 to 30 carbon atoms (e.g., 1,6-hexanediol diglycidyl ether, trimethylolpropane polyglycidyl ether), and aminoalcohols having 2 to 10 carbon atoms (e.g., ethanolamine, diethanolamine, 2-amino-2-methylpropanol, and triethanolamine). As the chain extender, diamines having 2 to 10 carbon atoms are preferred, secondary diamines are more preferred, and isophoronediamine is even more preferred. When polyurethane resins contain the above compounds as constituent monomers, the cohesive strength of the urethane groups is improved and the degree of swelling in water is reduced, resulting in excellent wet rub fastness. Furthermore, the use of diamines is preferred because the generation of carbon dioxide gas due to the elongation reaction with the amine is suppressed, reducing the amount of amine carbonate produced and improving storage stability.

[0060] The amount of chain extender used is preferably in the range of 0.2 to 2, more preferably 0.5 to 1.5, in terms of the ratio of the equivalent weight of the active hydrogen-containing group of the chain extender to the isocyanate group at the end of the urethane prepolymer.

[0061] If necessary, a reaction terminator can be used for the polyurethane resin. Examples of the reaction terminator include monoalcohols having 1 to 8 carbon atoms (methanol, ethanol, isopropanol, cellosolves, carbitols, etc.), and monoamines having 1 to 10 carbon atoms (mono- or di-alkylamines such as monomethylamine, monoethylamine, monobutylamine, dibutylamine, monooctylamine, etc.; mono- or di-alkanolamines such as monoethanolamine, diethanolamine, diisopropanolamine, etc.).

[0062] The method for producing the polyurethane resin of the present invention is not particularly limited, but examples thereof include the following methods [1] to [4]. [1] A method in which a polyol component, a tertiary amino group-containing polyol (a1-1), and a polyisocyanate component are reacted in one or more stages in the presence or absence of a hydrophilic solvent to produce a polyurethane resin having an isocyanate group at its terminal, and then a quaternization reaction is carried out with a quaternizing agent (a1-2). [2] A method for producing a polyurethane resin by reacting a tertiary amino group-containing polyol (a1-1) with a quaternizing agent (a1-2) in one or more stages in the presence or absence of a hydrophilic solvent to produce a quaternary ammonium compound (a1), and then reacting the quaternary ammonium compound (a1) with a polyol component and a polyisocyanate component in one or more stages. [3] A method in which a polyol component, a tertiary amino group-containing polyol (a1-1), and a polyisocyanate component are reacted in one or more stages in the presence or absence of a hydrophilic solvent to produce a polyurethane resin having an isocyanate group at its terminal, followed by reacting a chain extender and / or a reaction terminator with the isocyanate group in the polyurethane resin, and finally carrying out a quaternization reaction with a quaternizing agent (a1-2). [4] A method in which a polyol component, a tertiary amino group-containing polyol (a1-1), and a polyisocyanate component are reacted in one or more stages in the presence or absence of a hydrophilic solvent to produce a polyurethane resin having an isocyanate group at its terminal, and then the polyurethane resin is quaternized with a quaternizing agent (a1-2).The polyurethane resin is then dispersed in an aqueous medium, and the isocyanate groups in the polyurethane resin are reacted with a chain extender and / or a reaction terminator, and the hydrophilic solvent is then distilled off, if necessary. The polyurethane resins produced by the above methods [1] to [4] can be used to produce aqueous pigment dispersions. Among these, methods [1] to [3] are more preferred from the viewpoint of storage stability of the aqueous pigment dispersions.

[0063] The hydrophilic solvent used in the production of the polyurethane resin of [4] above includes those that are substantially non-reactive with isocyanate groups (ketones such as acetone and ethyl methyl ketone, esters, ethers, amides, and alcohols). Among these, tetrahydrofuran is preferred. The aqueous medium may be water alone, but a mixture of water and a hydrophilic solvent can also be used. The weight ratio of the hydrophilic solvent to water (hydrophilic solvent / water) is preferably 0 / 100 to 50 / 50, more preferably 35 / 65 to 45 / 55. When a hydrophilic solvent is used, it may be removed by distillation after the production of the polyurethane resin, if necessary.

[0064] The synthesis of the polyurethane resin is preferably carried out at a reaction temperature of 20° C. to 150° C., more preferably 60° C. to 110° C., and the reaction time is preferably 2 to 20 hours. The synthesis of polyurethane resins can be carried out in the presence or absence of an organic solvent that is substantially non-reactive with isocyanate groups. Polyurethane resins having terminal isocyanate groups typically have a free isocyanate group content of 0.5 to 10%. Examples of organic solvents that are substantially non-reactive with isocyanate groups include the hydrophilic solvents listed above, with tetrahydrofuran being preferred.

[0065] In producing polyurethane resins, a catalyst used in ordinary urethane reactions may be used to promote the reaction, if necessary. Examples of catalysts include amine catalysts such as triethylamine, N-ethylmorpholine, triethylenediamine, and cycloamidines described in U.S. Pat. No. 4,524,104 [e.g., 1,8-diaza-bicyclo(5,4,0)undecene-7 (DBU, manufactured by San-Apro Co., Ltd.)]; tin-based catalysts such as dibutyltin dilaurate, dioctyltin dilaurate, and tin octoate; and titanium-based catalysts such as tetrabutyl titanate.

[0066] The isocyanate group content in the polyurethane resin can be measured by the method specified in JIS K 1603-1. In the examples described herein, the isocyanate group content (NCO wt%) of the solvent solution was used.

[0067] The content of urea groups based on the weight of the polyurethane resin is preferably 0.01 to 0.2 wt%, more preferably 0.05 to 0.1 wt%. When the content of urea groups based on the weight of the polyurethane resin is 0.01 to 0.2 wt% (preferably 0.05 to 0.1 wt%), the content of urea groups in the polyurethane resin is appropriate, and it is preferable that both the mechanical strength and the viscosity of the aqueous dispersion can be achieved.

[0068] Examples of pigments for use in the present invention 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, metallic pigments, natural organic pigments, synthetic organic pigments, nitroso pigments, nitro pigments, pigment colorant-type azo pigments, azo lakes made from water-soluble dyes, azo lakes made from sparingly soluble dyes, lakes made from basic dyes, lakes made from acid dyes, xanthan lakes, anthraquinone lakes, pigments made from vat dyes, phthalocyanine pigments, and daylight fluorescent organic pigments).

[0069] Specific examples of organic and inorganic pigments are given below. Examples of white pigments include inorganic pigments such as titanium oxide, zinc white, zinc sulfide, antimony oxide, zirconium oxide, etc. In addition to inorganic pigments, hollow resin fine particles and polymer fine particles 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 hiding power tends to be insufficient, and if it exceeds 300 nm, the ejection stability tends to be insufficient.

[0070] Among these, it is preferable to use titanium oxide from the viewpoint of hiding power. The average particle size of titanium oxide is also preferably 200 to 300 nm.

[0071] Examples of pigments for magenta include, but are not limited to, 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.

[0072] Examples of yellow pigments include, but are not limited to, 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 CI Pigment Yellow 180.

[0073] 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.

[0074] 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 oxide; and organic pigments such as aniline black (CI Pigment Black 1).

[0075] In the aqueous pigment dispersion of the present invention, the total weight of the pigment and polyurethane resin is preferably 10 to 40% by weight, more preferably 20 to 30% by weight, from the viewpoint of storage stability.

[0076] In the aqueous pigment dispersion of the present invention, the ratio of pigment to polyurethane resin is preferably 80:20 to 20:80, in terms of initial dispersibility and rub fastness.

[0077] In a pigment aqueous dispersion, particles containing a pigment and a polyurethane resin are usually dispersed in water. From the viewpoints of storage stability and viscosity, the particle diameter of the particles in the pigment aqueous dispersion is preferably 100 to 200 nm, more preferably 120 to 180 nm, for color pigments. For white pigments, the particle diameter is preferably 200 to 400 nm, more preferably 220 to 300 nm. In the present invention, the particle diameter refers to the cumulant average diameter. The particle diameter can be measured and determined using a light scattering particle size distribution analyzer [e.g., "DLS-8000" manufactured by Otsuka Electronics Co., Ltd.].

[0078] <Method for producing aqueous pigment dispersion> Any of the conventionally known methods can be used to produce aqueous pigment dispersions, including a surface polymerization method in which a monomer is adsorbed and polymerized on the surface of a pigment dispersion, a surface deposition method in which a pigment is dispersed in a resin solution, a poor solvent for the resin is added, and the resin is deposited on the pigment surface, a kneading and micronization method in which the pigment and resin are melt-kneaded to form a masterbatch and then micronized in a wet manner, a method in which a resin solution is penetrated into pigment aggregates using a high-pressure fluid and micronized and coated simultaneously by the expansion energy generated when the resin solution is released under atmospheric pressure, a method in which an aqueous pigment and resin dispersion are micronized in a wet manner and then dispersed using mechanical energy, and a phase inversion emulsification method in which a pigment and a resin solution that is self-dispersible in water are micronized in a wet manner and then water is added to the solvent phase of the resin solution to obtain an aqueous pigment dispersion. Among these, the methods suitable for producing the aqueous pigment dispersion of the present invention from the viewpoints of initial dispersibility and storage stability are a wet method in which an aqueous pigment and resin dispersion is micronized and then dispersed by mechanical energy, and a phase inversion emulsification method. In the method of dispersing a pigment and resin aqueous dispersion using mechanical energy and the phase inversion emulsification method, the pigment particle surface is adsorbed or coated with a polyurethane resin having self-dispersibility that forms a coating film, and therefore the pigment, which is a colorant, can be fixed on the substrate without adding any other binder resin to the ink, which is also preferred from the viewpoint of fastness. The phase inversion emulsification method is preferable from the standpoint of storage stability because it has a structure in which the pigment surface is covered with resin, so the pigment surface is less frequently exposed to the ink, there is no compositional distribution as dispersed particles, and structural changes are less likely to occur. In the method of dispersing a pigment and resin aqueous dispersion using mechanical energy and the phase inversion emulsification method, a polyurethane resin with self-dispersibility that forms a coating film is adsorbed onto the surface of pigment particles, or the pigment particles are modified with a polyurethane resin with self-dispersibility that forms a coating film. This makes it possible to fix the pigment, which is a colorant, on the substrate without adding any other binder resin to the ink, and is therefore preferable from the standpoint of fastness. The phase inversion emulsification method is preferable from the viewpoint of storage stability because the pigment surface is modified with a resin, the pigment surface is less frequently exposed to the ink, there is no compositional distribution as dispersed particles, and structural changes are less likely to occur. In the aqueous pigment dispersion of the present invention, the polyurethane resin is adsorbed or adhered to the surface of pigment particles that are difficult to disperse alone in an aqueous medium, and thus the pigment particles having the resin adhered thereto are dispersed in the aqueous medium. The pigment particles having the resin adhered thereto are presumably resin-coated pigment particles in which the periphery of the pigment particle is coated with the polyurethane resin.

[0079] Specific embodiments of the method for producing the aqueous pigment dispersion include the following production methods [A] to [C]. [A] A method in which a pigment is added to a polyurethane resin solution containing a polyurethane resin having an isocyanate group terminal, which is produced by the method described in [1] for producing a polyurethane resin in this specification, and the mixture is mixed and homogenized. The polyurethane resin solution containing the pigment is then finely divided by mechanical crushing, and after the fine division, the carboxyl groups are converted into salts with a neutralizing agent and emulsified and dispersed in an aqueous medium, and a chain extender and / or a reaction terminator are reacted with the isocyanate groups in the polyurethane resin, and the hydrophilic solvent is then distilled off, if necessary. [B] A method in which a pigment is added to a polyurethane resin solution containing a polyurethane resin produced by the method described in [2] for producing a polyurethane resin in this specification, and the mixture is mixed and homogenized. The polyurethane resin solution containing the pigment is then micronized by mechanical crushing, and after the micronization, the carboxyl groups are converted into salts with a neutralizing agent, which are then emulsified and dispersed in an aqueous medium, and the hydrophilic solvent is distilled off as necessary. [C] A method in which a pigment is added to a polyurethane resin dispersion containing a polyurethane resin produced by the method [3] for producing a polyurethane resin in this specification, the mixture is mixed and homogenized, and the aqueous dispersion containing the pigment is then pulverized by mechanical crushing.

[0080] In the manufacturing methods [A] to [C] above, the equipment used for mixing and homogenizing can be the same as that used for synthesizing polyurethane resins, and examples of dispersing machines used for micronization include paint shakers, ball mills, sand mills, and nanomills. Specific examples include Dynomill (manufactured by Shinmaru Enterprises) and TSU-6U (manufactured by Imex).

[0081] In the methods [A] and [B] for producing aqueous pigment dispersions, the apparatus for emulsifying and dispersing in the aqueous medium is not particularly limited, and examples thereof include the following types of emulsifiers. 1) anchor-type stirring method, 2) rotor-stator type method [e.g., "Ebara Milder" (manufactured by Ebara Corporation)], 3) line mill type [e.g., line flow mixer], 4) static 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., Gaulin Homogenizer (Gaulin Co., Ltd.)], 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.

[0082] The aqueous pigment dispersion may contain additives such as emulsifiers, crosslinkers, weather stabilizers, and smoothing agents as needed. The additives may be used alone 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.

[0083] In one embodiment, the aqueous pigment dispersion of the present invention preferably contains an emulsifier. When the aqueous pigment dispersion of the present invention contains an emulsifier, the aqueous pigment dispersion has better storage stability after heating and better dry rubbing fastness. The emulsifier is preferably added during production of the aqueous pigment dispersion.

[0084] When an emulsifier is used in producing an aqueous pigment dispersion, the emulsifier may be added at any time during the production. In one embodiment, from the viewpoint of pigment dispersibility and aqueous dispersion stability, the emulsifier is preferably added before or during dispersion of the pigment in the polyurethane resin. The emulsifier may be added to either the polyurethane resin solvent solution or the aqueous medium, or both. When the emulsifier is reactive with the urethane prepolymer, it is preferable to add it to the aqueous medium. The amount of emulsifier added is preferably 0.2 to 10 wt %, more preferably 0.3 to 6 wt %, based on the weight of the pigment.

[0085] Examples of emulsifiers include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and other emulsifying dispersants. One type of emulsifier may be used, or two or more types may be used in combination. Among these, nonionic surfactants are preferred.

[0086] Examples of nonionic surfactants include aliphatic alcohol (carbon number 8-24) AO (carbon number 2-8) adducts (degree of polymerization = 1-100), polyhydric alcohol (carbon number 3-18) AO (carbon number 2-8) adducts (degree of polymerization = 1-100), (poly)oxyalkylene (carbon number 2-8, degree of polymerization = 1-100) higher fatty acid (carbon number 8-24) esters [for example, mono- or di-fatty acid polyethylene glycol esters such as monooleic acid polyethylene glycol ester (HLB = 6-17), monostearate polyethylene glycol ester (HLB = 8-15), distearate polyethylene glycol ester (HLB = 8-14)], polyhydric (dihydric to decahydric or higher) alcohol fatty acid (carbon number 8-24) esters [glycerin monostearate, ethylene glycol monostearate, fatty acid sorbitan esters (sorbitan monooleate)], and polyhydric (dihydric to decahydric or higher) alcohol fatty acid (carbon number 8-24) esters [glycerin monostearate, ethylene glycol monostearate, fatty acid sorbitan esters (sorbitan monooleate)]. sorbitan monolaurate, etc.), (poly)oxyalkylene (carbon number 2-8, degree of polymerization = 1-100) polyhydric (dihydric to decahydric or higher) alcohol higher fatty acid (carbon number 8-24) esters [polyoxyethylene sorbitan monolaurate (HLB = 10-16), polyoxyethylene methyl glucoside dioleate (HLB = 17), etc.], fatty acid alkanolamides [1:1 type coconut oil fatty acid diethanolamide, 1:1 type lauric acid diethanolamide, etc.], (poly)oxyalkylene (carbon number 2-8, degree of polymerization = 1-100) alkyl (carbon number 1-22) phenyl ethers, (poly)oxyalkylene (carbon number 2-8, degree of polymerization = 1-100) alkyl (carbon number 8-24) amino ethers, and alkyl (carbon number 8-24) dialkyl (carbon number 1-6) amine oxides [lauryl dimethylamine oxide, etc.]. Among these, mono- or di-fatty acid polyethylene glycol esters such as aliphatic alcohol (carbon number 8 to 24) AO (carbon number 2 to 8) adducts (HLB=5 to 18), polyhydric alcohol (carbon number 3 to 18) AO (carbon number 2 to 8) adducts (HLB=11 to 24), sorbitan monooleate, monooleic acid polyethylene glycol esters (HLB=6 to 17), monostearate polyethylene glycol esters (HLB=8 to 15), and distearate polyethylene glycol esters (HLB=8 to 14) are preferred. In one embodiment, the aqueous pigment dispersion of the present invention preferably contains a nonionic surfactant, as these surfactants provide excellent dry rub fastness and heat stability. Examples of preferred nonionic surfactants include aliphatic alcohol (8 to 24 carbon atoms) AO (2 to 8 carbon atoms) adducts (HLB=5 to 18), polyhydric alcohol (3 to 18 carbon atoms) AO (2 to 8 carbon atoms) adducts (HLB=11 to 24), sorbitan monooleate, and polyethylene glycol monooleate (HLB=6 to 17).

[0087] Examples of anionic surfactants include ether carboxylic acids or salts thereof having a hydrocarbon group having 8 to 24 carbon atoms [such as sodium lauryl ether acetate and (poly)oxyethylene (addition mole number 1 to 100) sodium lauryl ether acetate]; sulfates or ether sulfates and salts thereof having a hydrocarbon group having 8 to 24 carbon atoms [such as sodium lauryl sulfate, (poly)oxyethylene (addition mole number 1 to 100) sodium lauryl sulfate, (poly)oxyethylene (addition mole number 1 to 100) triethanolamine lauryl sulfate and (poly)oxyethylene (addition mole number 1 to 100) sodium coconut oil fatty acid monoethanolamide sulfate]; sulfonates having a hydrocarbon group having 8 to 24 carbon atoms [such as sodium dodecylbenzenesulfonate]; sulfosuccinates having one or two groups; phosphate esters or ether phosphate esters and salts thereof having a hydrocarbon group having 8 to 24 carbon atoms [such as sodium lauryl phosphate and (poly)oxyethylene (molar addition number 1 to 100) sodium lauryl ether phosphate]; fatty acid salts having a hydrocarbon group having 8 to 24 carbon atoms [such as sodium laurate and triethanolamine laurate]; and acylated amino acid salts having a hydrocarbon group having 8 to 24 carbon atoms [sodium coconut oil fatty acid methyl taurate, sodium coconut oil fatty acid sarcosine, triethanolamine coconut oil fatty acid sarcosine, triethanolamine N-coconut oil fatty acid acyl-L-glutamate, sodium N-coconut oil fatty acid acyl-L-glutamate, sodium lauroylmethyl-β-alanine, etc.].

[0088] Examples of cationic surfactants include quaternary ammonium salt types (stearyltrimethylammonium chloride, behenyltrimethylammonium chloride, distearyldimethylammonium chloride, lanolin fatty acid aminopropylethyldimethylammonium ethyl sulfate, etc.) and amine salt types (stearic acid diethylaminoethylamide lactate, dilaurylamine hydrochloride, oleylamine lactate, etc.).

[0089] 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-hydroxyethyl imidazolinium betaine, lauryl hydroxysulfobetaine, and lauroyl amidoethyl hydroxyethyl carboxymethyl betaine hydroxypropyl sodium phosphate), and amino acid-type amphoteric surfactants (such as sodium β-laurylaminopropionate).

[0090] Other emulsifying dispersants include, for example, polyvinyl alcohol, starch and its derivatives, cellulose derivatives such as carboxymethyl cellulose, methyl cellulose, and hydroxyethyl cellulose, carboxyl group-containing (co)polymers such as sodium polyacrylate, and emulsifying dispersants having urethane groups or ester groups described in U.S. Pat. No. 5,906,704 [for example, polylactone polyol and polyether polyol linked with polyisocyanate].

[0091] When the aqueous pigment dispersion contains an emulsifier, the content thereof is preferably 0.2 to 10% by weight, more preferably 0.3 to 6% by weight, based on the weight of the polyurethane resin.

[0092] The resulting pigment aqueous dispersion can be used to obtain an inkjet ink composition that is excellent in rub fastness and color development, particularly on unpretreated fabric.

[0093] The aqueous pigment dispersion or inkjet ink of the present invention may contain other components appropriately selected as necessary, such as dispersants, penetrants, pH adjusters, water-dispersible resins, antiseptics and antifungals, chelating agents, rust inhibitors, antioxidants, ultraviolet absorbers, oxygen absorbers, and light stabilizers.

[0094] <Water-based inkjet ink> In one embodiment, the inkjet ink contains the aqueous pigment dispersion of the present invention, water, and optionally a water-soluble organic solvent.

[0095] In one embodiment, the amount of the pigment aqueous dispersion in the inkjet ink 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 the ink.

[0096] In one embodiment, the total weight of the pigment and polyurethane resin in the inkjet ink is preferably 5 to 20% by weight, and more preferably 10 to 15% by weight, based on the total amount of the ink, from the viewpoint of storage stability.

[0097] In one embodiment, the weight of water in the inkjet ink is preferably 50 to 80% by weight, and more preferably 60 to 75% by weight, based on the total weight of the ink.

[0098] (Water-soluble organic solvent) When the medium of the inkjet ink is water, a water-soluble organic solvent may be contained to prevent the ink from drying, improve the dispersion stability of the pigment, etc. There are no particular restrictions on the water-soluble organic solvent, and it may be appropriately selected depending on the purpose.

[0099] The water-soluble organic solvent preferably contains a water-soluble solvent (hereinafter also referred to as a "high-boiling organic solvent") with a normal boiling point (hereinafter also referred to as "bp") of 180°C or higher. The inclusion of a high-boiling organic solvent improves the moisture retention of the nozzles and also enables optimization of the ink viscosity.

[0100] The "normal boiling point" means the boiling point at a pressure of 0.101 MPa. The high-boiling organic solvent may be one type or two or more types.

[0101] The content of the high boiling point organic solvent is preferably 1 to 40% by weight, more preferably 5 to 30% by weight, and even more preferably 10 to 25% by weight, relative to the total amount of the ink.

[0102] The water-soluble organic solvent is preferably a polyhydric alcohol. Such a polyhydric alcohol is not particularly limited and can be appropriately selected depending on the purpose. Examples of the water-soluble organic solvent include propylene glycol (bp 188°C), dipropylene glycol (bp 232°C), 1,5-pentanediol (bp 242°C), 3-methyl-1,3-butanediol (bp 203°C), 2-methyl-2,4-pentanediol (bp 197°C), ethylene glycol (bp 196°C to 198°C), tripropylene glycol (bp 267°C), hexylene glycol (bp 197°C), 1,6-hexanediol (bp 253°C), and the like. ~260°C), 1,2-hexanediol (bp 170°C), 1,2,6-hexanetriol (bp 178°C), 1,2,3-butanetriol, 1,2,4-butanetriol (bp 190°C to 191°C / 24hPa), glycerin (bp 290°C), diglycerin (bp 270°C / 20hPa), triethylene glycol (bp 285°C), tetraethylene glycol (bp 324 to 330°C), diethylene glycol (bp 245°C), 1,3-butanediol (bp 203 to 204°C), polypropylene glycol (bp 187°C), etc.

[0103] In addition to the water-soluble organic solvents, other water-soluble organic solvents or solid wetting agents may be used in combination with the ink, if necessary, in place of a part of these water-soluble organic solvents or in addition to these water-soluble organic solvents. Examples of other water-soluble organic solvents or solid wetting agents 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.

[0104] Examples of the polyhydric alcohol include polyethylene glycol (viscous liquid to solid), trimethylolethane (solid, mp 199°C to 201°C), and trimethylolpropane (solid, mp 61°C). Examples of the polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether (bp 135°C), ethylene glycol monobutyl ether (bp 171°C), diethylene glycol monomethyl ether (bp 194°C), diethylene glycol monobutyl ether (bp 231°C), ethylene glycol mono-2-ethylhexyl ether (bp 229°C), and propylene glycol monoethyl ether (bp 132°C). There are no particular restrictions on the content of the water-soluble organic solvent in the ink, and it can be selected appropriately depending on the purpose, but it is preferably 1 to 50% by weight.

[0105] (surfactant) The inkjet ink using the aqueous pigment dispersion of the present invention preferably contains a surfactant, which can improve the ejection properties of the ink, improve the wetting and spreading properties, and provide good image quality (color development).

[0106] Examples of surfactants include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and other emulsifying dispersants. 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.

[0107] The surfactant preferably contains a nonionic surfactant. By containing a nonionic surfactant, the ink can improve the ejection properties and wetting and spreading properties, thereby improving image quality (color development).

[0108] The surfactant preferably contains an alkyl ether type nonionic surfactant with an HLB value of 5 to 12. By containing such a surfactant, the ink can improve its ejection properties and wetting and spreading properties, thereby improving image quality (color development). In this embodiment, the HLB value refers to a value determined by the Griffin method.

[0109] The content of the 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 the ink.

[0110] The viscosity of an ink using the aqueous pigment dispersion of the present invention is preferably 3.0 to 10.0 mPa·s, and more preferably 3.5 to 6.0 mPa·s at 25° C. The viscosity can be measured using a cone and plate viscometer under the conditions described in the examples.

[0111] The inkjet ink containing the aqueous pigment dispersion of the present invention can be suitably used as an inkjet ink for, for example, coated paper for printing, cardboard, or cotton fabric. Printing methods using the inkjet ink are not particularly limited, and include home printing, commercial printing, sign graphic printing, pigment textile printing, etc. Pigment textile printing is preferred. [Example]

[0112] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these. Unless otherwise specified, "parts" below refer to parts by weight.

[0113] <Production Example 1> A reactor equipped with a condenser, thermometer, stirrer, and nitrogen inlet tube was charged with 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. 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 for another 6 hours at 200°C under a reduced pressure of 0.5 to 2.5 kPa. When the acid value (mg KOH / g) became less than 1, the reaction product was removed from the reactor, yielding a polyester polyol with a hydroxyl value (mg KOH / g) of 56.1. A simple pressurized reaction apparatus equipped with a stirrer and a heater was charged with 45.1 parts of the polyester polyol, 3.6 parts of 3-methyl-1,5-pentanediol, 7.5 parts of N-methyldiethanolamine as a polyol component having a tertiary amino group on the side chain, 36.9 parts of dicyclohexylmethane-4,4-diisocyanate (hydrogenated MDI) as an organic polyisocyanate component, and 100 parts of tetrahydrofuran as an organic solvent for the reaction. The mixture was stirred at 70°C for 12 hours to carry out a urethane reaction, and then 6.9 parts of dimethyl sulfate was charged and the mixture was 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.

[0114] <Production Example 2> A simple pressurized reaction apparatus equipped with a stirrer and a heater was charged with 45.1 parts of polycarbonate polyol [Ethanocol 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 on the side chain, 36.9 parts of dicyclohexylmethane-4,4-diisocyanate (hydrogenated MDI) as an organic polyisocyanate component, and 100 parts of tetrahydrofuran as an organic solvent for the reaction. The mixture was stirred at 70°C for 12 hours to carry out a urethanization reaction, and then 6.9 parts of dimethyl sulfate was added and the reaction was carried out at 50°C for 4 hours to produce a solvent solution of a polyurethane resin (P-2) containing a quaternary ammonium salt and having an isocyanate group.

[0115] <Production Examples 3 to 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 amounts used were changed to those shown in Table 1.

[0116] <Production Example 13> 30 parts of the solvent solution of polyurethane resin (P-4) obtained in Production Example 4 was added to a vessel equipped with a stirrer, and 84.4 parts of water was added while stirring at 200 rpm to disperse the mixture. 0.64 parts of isophoronediamine (IPDA), a chain extender, was added to the resulting dispersion with stirring, and an extension reaction was carried out for 30 minutes. Tetrahydrofuran was then distilled off under reduced pressure at 60°C for 2 hours. Water was added to adjust the solids concentration to 16.7% by weight, yielding a dispersion of polyurethane resin (P-13).

[0117] <Production Example 14> 57 parts of myristyl alcohol and 0.08 parts of potassium hydroxide were placed in a pressure-resistant reactor equipped with a thermometer, a heating / cooling device, a stirrer, and a dropping bomb, and after replacing the atmosphere with nitrogen, the vessel was sealed and heated to 140° C. With stirring, 43 parts of ethylene oxide were added dropwise at 140° C. over 5 hours while adjusting the pressure to 0.5 MPa or less, and the mixture was then aged at the same temperature for 3 hours to obtain a myristyl alcohol ethylene oxide 4-mol adduct (O-1).

[0118] <Production Example 15> 36 parts of oleyl alcohol and 0.08 parts of potassium hydroxide were placed in a reaction vessel similar to that in Production Example 14, and after replacing the atmosphere with nitrogen, the vessel was sealed and heated to 140° C. With stirring, 64 parts of ethylene oxide were added dropwise at 140° C. over 5 hours while adjusting the pressure to 0.5 MPa or less, and the mixture was then aged at the same temperature for 3 hours to obtain an 11-mol ethylene oxide adduct of oleyl alcohol (O-2).

[0119] <Production Example 16> 15 parts of sorbitol and 0.08 parts of potassium hydroxide were placed in a reaction vessel similar to that in Production Example 14, and after replacing the atmosphere with nitrogen, the vessel was sealed and heated to 140° C. With stirring, 85 parts of ethylene oxide were added dropwise at 140° C. over 5 hours while adjusting the pressure to 0.5 MPa or less, and the mixture was then aged at the same temperature for 3 hours to obtain a sorbitol-ethylene oxide 24 mol adduct (O-3).

[0120] <Production Example 17> Into a reaction vessel equipped with a condenser, a thermometer, a stirrer, and a nitrogen inlet tube, 39 parts of sorbitol, 61 parts of oleic acid, and 50 parts of xylene as a solvent were charged, and the mixture was reacted for 3 hours under a nitrogen stream at 180°C while distilling off the water produced. When the acid value (mgKOH / g) became less than 1, the reaction system was reduced in pressure and the xylene was removed, yielding an ester of sorbitol and oleic acid (O-4).

[0121] <Production Example 18> Into a reaction vessel equipped with a condenser, thermometer, stirrer, and nitrogen inlet tube, 68 parts of polyoxyethylene monomethyl ether (Sigma-Aldrich, Mn=550), 32 parts of oleic acid, and 50 parts of xylene as a solvent were charged, and the mixture was reacted for 3 hours under a nitrogen stream at 180°C while distilling off the water produced. When the acid value (mgKOH / g) became less than 1, the reaction system was reduced in pressure, and the xylene was removed to obtain polyethylene glycol oleate (O-5).

[0122] <Production Example 19> Into 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., Inc.), 56 parts of oleic acid, and 50 parts of xylene as a solvent were charged, and the mixture was reacted for 3 hours under a nitrogen stream at 180°C while distilling off the water produced. When the acid value (mgKOH / g) became less than 1, the reaction system was reduced in pressure, and the xylene was removed to obtain polyethylene glycol oleate (O-6).

[0123] <Comparative Manufacturing Examples 1 to 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 amounts used were changed to those shown in Table 1.

[0124] <Comparative Manufacturing Example 4> A reaction vessel equipped with a condenser, thermometer, stirrer, and nitrogen inlet tube was charged with 59 parts of polypropylene glycol diglycidyl ether (epoxy equivalent: 201 g / equivalent), and the atmosphere inside the vessel was replaced with nitrogen. The vessel was then heated to 70°C, and 38 parts of di-n-butylamine was added dropwise using a dropping device. After completion of the addition, the reaction was allowed to proceed for 10 hours at 90°C. After completion of the reaction, an infrared spectrophotometer was used to confirm that the absorption peak near 842 cm-1 attributed to the epoxy groups in the reaction product had disappeared, yielding a tertiary amino group-containing polyol (amine value and hydroxyl value both 165.5 mgKOH / g). A reactor equipped with a condenser, thermometer, stirrer, and nitrogen inlet tube was charged with 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). 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 for another 6 hours at 200°C under a reduced pressure of 0.5 to 2.5 kPa. When the acid value (mg KOH / g) became less than 1, the reaction product was removed from the reactor, yielding a polyester polyol with a hydroxyl value (mg KOH / g) of 58.9. A simple pressurized reaction apparatus equipped with a stirrer and a heater was charged with 48.6 parts of polycarbonate polyol [Ethanocol UH-200 manufactured by Ube Industries, Ltd.], 24.2 parts of the polyester polyol (neopentyl glycol-1,4-butanediol-terephthalic acid-adipic acid copolymer), 5.8 parts of the tertiary amino group-containing polyol, 19.3 parts of dicyclohexylmethane-4,4-diisocyanate (hydrogenated MDI) as a polyisocyanate component, and 100 parts of ethyl acetate as an organic solvent for the reaction, and the mixture was stirred at 70°C for 12 hours to carry out a urethanization reaction. After the reaction, 3.2 parts of "Aminosilane A1100" (γ-aminopropyltriethoxysilane, manufactured by Nippon Unicar Co., Ltd.) was added and reacted for 1 hour to prepare a solution of urethane prepolymer in ethyl acetate. Next, 1.0 part of hydrazine hydrate was added to the urethane prepolymer solution, and a chain extension reaction was carried out for 1 hour. Next, 134.6 parts of ethyl acetate and 2.1 parts of dimethyl sulfate were added, and the mixture was maintained at 50°C for 4 hours. After that, 227.3 parts of water was added while stirring at 200 rpm to disperse the mixture. The ethyl acetate was distilled off under reduced pressure at 60°C for 2 hours. Water was added to adjust the solids concentration to 16.7% by weight, yielding a dispersion of polyurethane resin (P'-4).

[0125] The composition and physical properties of the polyurethane resin are shown in Table 1. In Table 1, the weight proportion of the quaternary ammonium compound (a1) was calculated according to the following formula. Weight percentage (%) of quaternary ammonium compound (a1) = {[(a1-1) + (a1-2)] / [Polyol other than quaternary ammonium compound (a1) + (a1-1) + (a1-2) + (B)]} × 100 In Comparative Production Examples 1 to 3, the quaternizing agent (a1-2) was not used, and therefore the quaternary ammonium compound (a1) was not present, and its weight percentage (%) was 0%.

[0126] [Table 1]

[0127] Example 1 30 parts of the polyurethane resin (P-1) solvent solution prepared in Production Example 1 and 120 parts of tetrahydrofuran were added to the vessel of a pigment disperser (TSU-6U, manufactured by Imex) and stirred until the resin was uniformly dissolved. Next, 10 parts of a cyan 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 passing 4°C cooling water through the jacket. The resulting dispersion slurry was stirred at 200 rpm while 100 parts of water was added to disperse the mixture. 0.64 parts of isophoronediamine (IPDA), a chain extender, was added to the resulting dispersion with stirring, and an extension reaction was carried out for 30 minutes. Tetrahydrofuran was then distilled off under reduced pressure at 60°C for 2 hours, and the glass beads were removed by filtration. Water was added to adjust the solids concentration to 25% by weight, yielding a pigment aqueous dispersion (Q-1).

[0128] <Examples 2 to 25> Aqueous pigment dispersions (Q-2) to (Q-25) were obtained in the same manner as in Example 1, except that the raw materials and amounts used were changed to those shown in Tables 2 and 3. Nonionic surfactants (O-1) to (O-6) were used in Examples 16 to 25. When a nonionic surfactant was used, at the beginning of the process shown in Example 1, the nonionic surfactant was added to the vessel of a pigment disperser (TSU-6U, manufactured by Imex) together with a solvent solution of the polyurethane resin and tetrahydrofuran, and the mixture was stirred until the resin was uniformly dissolved.

[0129] <Example 26> 30 parts of the solvent solution of polyurethane resin (P-4) prepared in Production Example 4, 50 parts of tetrahydrofuran, and 0.5 parts of polyethylene glycol oleate (O-6) prepared in Production Example 19 were added to the vessel of a pigment disperser (TSU-6U, manufactured by Imex) and stirred until the resin was uniformly dissolved. 1.51 parts of the chain extender isophoronediamine (IPDA) was added with stirring and the chain extension reaction was carried out for 30 minutes. Next, 10 parts of a cyan pigment (Heliogen Blue D7088 manufactured by BASF) and 140 parts of glass beads (ASGB-320 manufactured by AS ONE) were added, and the mixture was dispersed for 3 hours while passing 4°C cooling water through the jacket. The obtained dispersion slurry was stirred at 200 rpm, and 100 parts of water was added to disperse the mixture. Tetrahydrofuran was distilled off 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 to 25% by weight, thereby obtaining an aqueous pigment dispersion (Q-26).

[0130] Example 27 To the vessel of a pigment disperser (TSU-6U, manufactured by Imex), 90 parts of the dispersion of polyurethane resin (P-13) prepared in Production Example 13, 0.5 parts of the polyethylene glycol oleate (O-6) prepared in Production Example 19, 10 parts of a cyan pigment [Heliogen Blue D7088 manufactured by BASF], and 140 parts of glass beads [ASGB-320 manufactured by AS ONE] were added, and the mixture was dispersed for 3 hours while passing cooling water at 4°C through the jacket. The glass beads were then removed by a filter, and water was added to adjust the solids concentration to 25 wt%, yielding an aqueous pigment dispersion (Q-27).

[0131] <Comparative Examples 1 to 3> Aqueous pigment dispersions (Q'-1) to (Q'-3) were obtained in the same manner as in Example 1, except that the raw materials and amounts used were changed to those shown in Table 4.

[0132] <Comparative Example 4> 90 parts of the dispersion of polyurethane resin (P'-4) prepared in Comparative Production Example 4, 10 parts of a cyan pigment [Heliogen Blue D7088 manufactured by BASF], and 140 parts of glass beads [ASGB-320 manufactured by AS ONE] were added to the vessel of a pigment disperser (TSU-6U manufactured by Imex), and the mixture was dispersed for 3 hours while passing cooling water at 4°C through the jacket. The glass beads were then removed by a filter, and water was added to adjust the solids concentration to 25% by weight, yielding an aqueous pigment dispersion (Q'-4).

[0133] Tables 2 to 4 show the blending amounts, physical property values, and evaluation results of the aqueous pigment dispersions obtained in each of the Examples and Comparative Examples.

[0134] [Table 2]

[0135] [Table 3]

[0136] [Table 4]

[0137] [Evaluation method] The measurement and evaluation methods for the obtained pigment aqueous dispersions will be described below.

[0138] <Method for measuring particle size> The particle sizes of the aqueous pigment dispersions (Q-1) to (Q-27) and (Q'-1) to (Q'-4) obtained in Examples 1 to 27 or Comparative Examples 1 to 4 were measured using a light scattering particle size distribution analyzer ("ELSZ-1000" manufactured by Otsuka Electronics Co., Ltd.), and the obtained cumulant average size was used as the particle size.

[0139] <How to check the particle shape of aqueous pigment dispersion> To a heated aqueous gelatin solution, 0.1% by weight of each of the aqueous pigment dispersions (Q-1) to (Q-27) and (Q'-1) to (Q'-4) obtained in Examples 1 to 27 or Comparative Examples 1 to 4 was added, homogenized, and then cooled to room temperature and further cooled in a refrigerator for 2 hours or more to solidify. The solidified sample was cut into a thin layer using a microtome, and the polyurethane resin was stained with phosphotungstic acid. After staining, the TEM image of the sample was observed, and the shape of the particles was confirmed from the circularity of the observed particles. Evaluation was based on the following criteria. ◯: Circularity is greater than 0.95 △: Circularity is greater than 0.90 and less than 0.95 ×: Circularity is 0.90 or less

[0140] <Ink manufacturing> Evaluation inks (R-1) to (R-27) and comparative inks (R'-1) to (R'-4) were produced by uniformly mixing 50.0 parts each of the aqueous pigment dispersions (Q-1) to (Q-27) and (Q'-1) to (Q'-4) obtained in Examples 1 to 27 or Comparative Examples 1 to 4, 15.0 parts of glycerin, 1.0 part of BTG (triethylene glycol butyl ether), 0.5 parts of Olfine E1010 (manufactured by Nissin Chemical Industry Co., Ltd.), and 33.5 parts of water, and then removing any insoluble matter using a filter. The aqueous pigment dispersion (Q'-3) using a tertiary amine salt aggregated in a basic pH range, and therefore could not be evaluated as an ink. In the column "Dispersibility after adjusting ink composition (pH 8)", cases where the particles of the pigment aqueous dispersion were dispersed in the ink were indicated by "O", and cases where the particles of the pigment aqueous dispersion were aggregated in the ink were indicated by "X".

[0141] <Evaluation of initial ink dispersibility> The initial dispersibility of the ink was evaluated from the results of measuring the particle diameter of the aqueous pigment dispersion in the ink prepared above and the ink viscosity. The particle size of the pigment aqueous dispersion in the ink using the color pigment (cyan, magenta, yellow, and black in each of the Examples and Comparative Examples) was evaluated according to the following criteria. ○: Cumulant mean diameter is 180 nm or less ×: Cumulant mean diameter is greater than 180 nm The particle size of the aqueous pigment dispersion in the ink using the white pigment was evaluated according to the following criteria. ○: Cumulant mean diameter is 300 nm or less ×: Cumulant mean diameter is greater than 300 nm The ink viscosity was evaluated according to the following criteria. ○: Ink viscosity is 6.0 mPa·s or less ×: Ink viscosity greater than 6.0 mPa·s Based on the results of particle size and viscosity measurements, the initial dispersibility of the ink was evaluated according to the following criteria. Good: Both the cumulant mean diameter and ink viscosity are good ×: Either the cumulant mean diameter or the ink viscosity or both are × <Method for measuring particle size of aqueous pigment dispersion in ink> The measurement was carried out in the same manner as for the aqueous pigment dispersion. Aggregated (R'-3) was excluded from the analysis.

[0142] <Method for measuring ink viscosity> The viscosities of the evaluation inks (R-1) to (R-27) and the comparative inks (R'-1), (R'-2), and (R'-4) were measured using the following measuring device and conditions. Device: MCR102 (manufactured by Anton Paar) Jig: 75mm corn plate Shear rate: 1000 1 / s Measurement temperature: 20℃ Aggregated (R'-3) was excluded from the analysis.

[0143] <Evaluation of ink storage stability> The storage stability of the ink was evaluated by leaving the ink in a circulating air dryer set at 60°C for 5 days and measuring the rate of change in particle size of the aqueous pigment dispersion in the ink and the rate of change in ink viscosity before and after the test. The rate of change is calculated using the following formula. Particle size change rate of aqueous pigment dispersion in ink: (S2-S1) / S1 x 100 (%) Ink viscosity change rate: (V2-V1) / V1 x 100(%) S1: Particle size of aqueous pigment dispersion in ink before testing S2: Particle size of aqueous pigment dispersion in ink after test V1: Ink viscosity before test V2: Ink viscosity after test The evaluation criteria are as follows: ○: The change rate of particle size and ink viscosity is within ±10% ×: Either the particle size or the ink viscosity change rate, or both, are greater than +10% or less than -10%

[0144] <Evaluation method for dry rub fastness (abrasion resistance) on cotton fabric: color ink> Plain cotton broadcloth (100% cotton) was printed with the evaluation inks (R-1) to (R-14), (R-16) to (R-24), (R-26) to (R-27), and the comparative inks (R'-1), (R'-2), and (R'-4) using a modified Seiko Epson PX-G930 inkjet printer. The inks were then dried at 160°C for 10 minutes to prepare test pieces (21 cm x 28 cm) coated with pigment and polyurethane resin on the plain cotton broadcloth. Dry rub fastness was evaluated according to JIS L0849-2. The test pieces were rubbed 100 times with a 200 g load. The dye transfer density on the No. 3 gold cloth side was measured at nine points using a spectrophotometer (X-rite 938, manufactured by X-Rite). The average value of the measurement results was used as the dye transfer density. The dye transfer density was evaluated according to the following criteria, and the results are shown in Tables 2 to 4. The lower the dye transfer density, the better the dry rub fastness. ◎: Dye migration concentration 0.10 or less ○: Dye transfer density is greater than 0.10 and less than 0.15 △: Dye transfer density is greater than 0.15 and less than 0.20 ×: Dye transfer density is greater than 0.20 and less than 0.30 A dye transfer density of 0.15 or less is a practical level.

[0145] <Evaluation method for dry rub fastness (abrasion resistance) on cotton fabric: White ink> The evaluation inks (R-15) and (R-25) were printed on plain black cotton broadcloth [100% black cotton by mass] using a modified Seiko Epson PX-G930 inkjet printer, and then dried at 160°C for 10 minutes to prepare test specimens (21 cm x 28 cm) in which the pigment and polyurethane resin were coated on the plain black cotton broadcloth. Dry rubbing fastness was evaluated according to JIS L0849-2. The print surface was rubbed back and forth 100 times with a load of 200 g. The print surface was measured at nine points before and after rubbing using a spectrophotometer [X-rite 938 manufactured by X-Rite Corporation], and the average difference between the measurement results before and after rubbing was calculated as ΔL * ΔL * The results are shown in Tables 2 and 3. * The lower the value, the better the resistance to rubbing. ◎:ΔL * ≦0.3 〇:0.3<ΔL* ≦1.0 △:1.0<ΔL * ≦5.0 ×:5.0<ΔL *

[0146] <Method for evaluating wet rubbing fastness (abrasion resistance) on cotton fabric: Color ink> Plain cotton broadcloth (100% cotton) was printed with the evaluation inks (R-1) to (R-14), (R-16) to (R-24), (R-26) to (R-27), and the comparative inks (R'-1), (R'-2), and (R'-4) using a modified Seiko Epson PX-G930 inkjet printer. The inks were then dried at 160°C for 10 minutes to prepare test pieces (21 cm x 28 cm) coated with pigment and polyurethane resin on the plain cotton broadcloth. Wet rub fastness was evaluated according to JIS L0849-2. The test pieces were rubbed 100 times with a 200 g load. The dye transfer density on the No. 3 gold cloth side was measured at nine points using a spectrophotometer (X-rite 938, manufactured by X-Rite). The average value of the measurement results was used as the dye transfer density. The dye transfer density was evaluated according to the following criteria, and the results are shown in Tables 2 to 4. The lower the migration density, the better the wet rub fastness. ◎: Dye migration concentration 0.20 or less ○: Dye transfer density is greater than 0.20 and less than 0.25 △: Dye transfer density is greater than 0.25 and less than 0.30 ×: Dye transfer density is greater than 0.30 and less than 0.40 A dye transfer density of 0.25 or less is a practical level.

[0147] <Wet rubbing fastness (abrasion resistance) evaluation method for cotton fabric: White ink> The evaluation inks (R-15) and (R-25) were printed on plain black cotton broadcloth [100% black cotton by mass] using a modified Seiko Epson PX-G930 inkjet printer, and then dried at 160°C for 10 minutes to prepare test pieces (21 cm x 28 cm) in which the pigment and polyurethane resin were coated on the plain black cotton broadcloth. The wet rubbing fastness was evaluated in accordance with JIS L0849-2. The test piece was rubbed back and forth 100 times with a load of 200 g. The printed surface was measured at nine points before and after rubbing using a spectrophotometer [X-rite 938 manufactured by X-Rite], and the average value of the difference in the measurement results before and after rubbing was calculated as ΔL. * ΔL * The results are shown in Tables 2 and 3. * The lower the value, the better the resistance to rubbing. ◎:ΔL * ≦0.3 〇:0.3<ΔL * ≦1.0 △:1.0<ΔL * ≦5.0 ×:5.0<ΔL *

[0148] <Evaluation method for color development on cotton fabric: color ink> Evaluation inks (R-1) to (R-14), (R-16) to (R-24), (R-26) to (R-27), and comparative inks (R'-1), (R'-2), and (R'-4) were printed on plain cotton broadcloth (100% cotton) using a modified Seiko Epson PX-G930 inkjet printer. The prints were then dried at 160°C for 10 minutes to prepare test pieces (21 cm x 28 cm) coated with pigment and polyurethane resin on the plain cotton broadcloth. Image density was measured at nine points using a spectrophotometer (X-rite 938, X-Rite). The average of the measurement results was used as the image density. Image density was evaluated according to the following criteria, and the results are shown in Tables 2 to 4. The higher the image density, the better the color development. 〇: Image density 1.3 or more △: Image density 1.2 or more and less than 1.3 ×: Image density less than 1.2 An image density of 1.3 or more is a practical level.

[0149] <Evaluation method for color development on cotton fabric: White ink> The evaluation inks (R-15) and (R-25) were printed on plain black cotton broadcloth [100% black cotton by mass] using a modified Seiko Epson PX-G930 inkjet printer, and then dried at 160°C for 10 minutes to prepare test specimens (21 cm x 28 cm) in which the pigment and polyurethane resin were coated on the plain cotton broadcloth. Image density L * The value is used to determine the L * The value was measured at nine points using a spectrophotometer [X-rite 938 manufactured by X-Rite], and the average value of the measurement results was used. * The results are shown in Tables 2 and 3. * The higher the value, the better the color development. 〇:L * is 70 or more △:L * is between 50 and 70 ×:L * is less than 50

[0150] <Filterability after heating> To evaluate the filterability after heating, the ink was left to stand in a circulation dryer set at 60°C for 5 days, and then suctioned using a water aspirator (maximum vacuum: approximately 24 mmHg) and filtered under reduced pressure. The filters used were a prefilter (φ47 mm, 100 sheets, AP2504700 / 2-3055-07) and an MF-Millipore membrane (cellulose mixed ester, hydrophilic, 8.0 μm, 47 mm, white). Evaluation was performed based on the weight of ink that could pass through. The evaluation criteria were as follows: The results are shown in Tables 2 to 4. ◎:300g or more 〇: 100g or more but less than 300g △: 50g or more but less than 100g ×: Less than 50g

[0151] <Continuous printing test> The ink produced as described above was loaded into a modified Seiko Epson PX-G930 inkjet printer. Solid images were continuously printed at a resolution of 1440 x 720 dpi, and the print quality was evaluated for streaking. The evaluation criteria were as follows. The results are shown in Tables 2 to 4. ◎: No streaks or unevenness occurs for more than 24 hours 〇: Streaks appear after 5 hours or more but less than 24 hours △: Streaks appear after 1 hour or more but less than 5 hours ×: Streaks appear in less than an hour

[0152] The evaluation inks (R-1) to (R-27) exhibited excellent initial dispersibility, storage stability, and abrasion resistance. They also exhibited excellent color development on untreated cotton fabric. Comparative inks (R'-1) and (R'-2), which did not contain a quaternary ammonium compound, exhibited insufficient color development (Comparative Examples 1 and 2). Comparative ink (R'-3), which did not contain a quaternary ammonium compound, exhibited particle aggregation under basic conditions, resulting in insufficient initial dispersibility and storage stability (Comparative Example 3). Comparative ink (R'-4), in which the weight ratio of the quaternary ammonium compound (a1) in the polyurethane resin was 7.9 wt % based on the total weight of the active hydrogen atom-containing component (A) and the organic polyisocyanate component (B), exhibited insufficient initial dispersibility and storage stability, and exhibited insufficient color development (Comparative Example 4). [Industrial Applicability]

[0153] The aqueous pigment dispersion of the present invention has excellent initial dispersion stability and storage stability, and is particularly excellent in color development on non-pretreated fabrics, and is therefore useful as an aqueous pigment dispersion for producing an inkjet ink composition for printing on cotton fabrics.

Claims

1. An aqueous pigment dispersion for an aqueous inkjet ink, comprising: a pigment dispersed in a polyurethane resin obtained by reacting an active hydrogen atom-containing component (A) with an organic polyisocyanate component (B); and an aqueous medium, The aqueous pigment dispersion, wherein the active hydrogen atom-containing component (A) contains a quaternary ammonium compound (a1), and the weight proportion 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 pigment dispersion according to claim 1, wherein the quaternary ammonium compound (a1) is a compound represented by the following general formula (1) and / or the following general formula (2): 【Chemical 1】 [In general formula (1), R １ 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.] 【Chemistry 2】 [In general formula (2), R ５ ~R ７ are each independently an alkyl group having 1 to 4 carbon atoms, and X － is an anion.]

3. 3. The aqueous pigment dispersion according to claim 1, wherein the active hydrogen atom-containing component (A) comprises at least one selected from the group consisting of polycarbonate polyols, polyester polyols, and polyether polyols.

4. 4. The aqueous pigment dispersion according to claim 3, wherein the polycarbonate polyol is a crystalline polycarbonate polyol.

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