Aqueous polyurethane resin dispersion for inkjet printing

Abstract

To provide a polyurethane resin aqueous dispersion which gives a dry film having excellent scratch resistance even when applied to an impermeable recording medium such as PET and OPP.SOLUTION: A polyurethane resin aqueous dispersion for inkjet ink contains: a polyurethane resin (U) obtained by reacting a polyol component with a polyisocyanate component; and water. The polyurethane resin (U) has a carboxyl group and / or a carboxylate anion group. The polyol component contains a polycyclic aliphatic diol. The polyisocyanate component contains an aromatic isocyanate and an aliphatic isocyanate.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an aqueous polyurethane resin dispersion for inkjet printing. [Background technology]

[0002] Inkjet recording methods are widely used because they can record a wide variety of high-quality images on a wide variety of recording media by ejecting ink droplets from a large number of nozzles provided in an inkjet head. Inkjet printing has been extensively studied due to technological advances in pigment dispersions with excellent weather resistance, and there is also a demand for abrasion resistance to prevent color fading and deterioration of printed images due to friction or other factors that may occur when an external force is applied to the surface of a printed image. Examples of inkjet recording inks with excellent abrasion resistance include inks containing a pigment, an aqueous resin, and an aqueous medium, in which the aqueous resin is a polyurethane resin having a polyoxyethylene structure (Patent Document 1) and a polyurethane resin having an alicyclic structure (Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-1639 [Patent Document 1] International Publication No. 2011 / 004675 Summary of the Invention [Problem to be solved by the invention]

[0004] However, although images printed using conventional inkjet recording inks have a degree of abrasion resistance sufficient to prevent pigments from falling off due to rubbing and the like when printed on inkjet-specific paper and the like, as the range of fields in which printed materials are used expands, a higher level of abrasion resistance is required. For example, when printed on non-permeable recording media such as polyethylene terephthalate (PET) and polypropylene (OPP) film, the application of external force can cause discoloration or damage due to pigment falling off and the like, and the current situation is still not satisfactory. An object of the present invention is to provide an aqueous polyurethane resin dispersion which produces a dried film that has excellent abrasion resistance even when applied to an impermeable recording medium such as PET or OPP. [Means for solving the problem]

[0005] As a result of extensive research, the present inventors have arrived at the present invention. Specifically, the present invention provides an aqueous polyurethane resin dispersion for use in inkjet inks, which contains water and a polyurethane resin (U) obtained by reacting a polyol component with a polyisocyanate component, wherein the polyurethane resin (U) is a polyurethane resin having a carboxyl group and / or a carboxylate anion group, the polyol component is a polyol component containing a polycyclic aliphatic diol, and the polyisocyanate component is a polyisocyanate component containing an aromatic isocyanate and an aliphatic isocyanate. [Effects of the Invention]

[0006] The present invention makes it possible to provide an aqueous polyurethane resin dispersion in which the resulting dried film has excellent abrasion resistance even when applied to an impermeable recording medium such as PET or OPP. DETAILED DESCRIPTION OF THE INVENTION

[0007] The aqueous polyurethane resin dispersion of the present invention contains water and a polyurethane resin (U) obtained by reacting a polyol component with a polyisocyanate component.

[0008] The polyol component in the present invention contains a polycyclic aliphatic diol as an essential component from the viewpoints of abrasion resistance and solubility in a polymerization solvent. The polycyclic aliphatic diol may be used alone, in combination of two or more kinds, or in combination with a polyol component other than the polycyclic aliphatic diol.

[0009] The polycyclic aliphatic diol is not particularly limited, and examples thereof include diols having bridged rings such as norbornane rings, bicyclooctane rings, bicycloundecane rings, adamantane rings, tricyclodecane rings, and tetracyclododecane rings, and diols having spiro rings. Specific examples include 2,5-norbornanediol, bicyclo[2.2.2]octane-1,4-dimethanol, 1,3-adamantanediol, and tricyclodecane dimethanol (e.g., tricyclo[5.2.1.0(2,6)]decane dimethanol). From the viewpoints of abrasion resistance, solubility in polymerization solvents, and dispersion stability of resin particles, diols having bridged rings such as norbornane rings, bicyclooctane rings, adamantane rings, and tricyclodecane rings are preferred, more preferably diols having tricyclodecane rings (e.g., tricyclodecane dimethanol), and even more preferably tricyclo[5.2.1.0(2,6)]decane dimethanol.

[0010] The polyol component other than the polycyclic aliphatic diol is not particularly limited, and examples thereof include a polymer diol, a diol having a carboxyl group and / or a carboxylate anion group, and a low-molecular-weight polyol other than the polycyclic aliphatic diol, etc. Furthermore, since the polyurethane resin (U) is a polyurethane resin having a carboxyl group and / or a carboxylate anion group, the polyol component preferably contains a diol having a carboxyl group and / or a carboxylate anion group from the viewpoint of introducing a carboxyl group and / or a carboxylate anion group into the polyurethane resin (U).

[0011] The polymer diol is not particularly limited, but examples thereof include polyether polyol, polycarbonate polyol, polyester polyol, and polyolefin polyol.

[0012] The polyether polyol is not particularly limited, but examples thereof include aliphatic polyether diols and aromatic polyether diols.

[0013] The aliphatic polyether diol is not particularly limited, but examples thereof include adducts of alkylene oxides (hereinafter abbreviated as AO) having 2 to 12 carbon atoms with aliphatic polyhydric alcohols having 2 to 20 carbon atoms. Specific examples thereof include polyoxyalkylene glycols (polyethylene glycol, etc.), polyoxypropylene glycols (polypropylene glycol, etc.), polyoxyethylene / propylene glycols, and polytetramethylene ether glycols.

[0014] Commercially available aliphatic polyether diols include PTMG1000 (poly(oxytetramethylene) glycol having an Mn of 1000, manufactured by Mitsubishi Chemical Corporation), PTMG2000 (poly(oxytetramethylene) glycol having an Mn of 2000, manufactured by Mitsubishi Chemical Corporation), PTMG3000 (poly(oxytetramethylene) glycol having an Mn of 3000, manufactured by Mitsubishi Chemical Corporation), PTGL2000 (modified poly(oxytetramethylene) glycol having an Mn of 2000, manufactured by Hodogaya Chemical Co., Ltd.), PTGL3000 (modified poly(oxytetramethylene) glycol having an Mn of 3000, manufactured by Hodogaya Chemical Co., Ltd.), and Sannix PP-2000 (polyoxypropylene glycol having an Mn of 2000, manufactured by Sanyo Chemical Industries, Ltd.). In this embodiment, "Mn" refers to the number average molecular weight.

[0015] The aromatic polyether diol is not particularly limited, and examples thereof include diols having a bisphenol skeleton such as ethylene oxide (hereinafter abbreviated as EO) adducts of bisphenol A (such as an adduct of bisphenol A with 2 moles of EO, an adduct of bisphenol A with 4 moles of EO, an adduct of bisphenol A with 6 moles of EO, an adduct of bisphenol A with 8 moles of EO, an adduct of bisphenol A with 10 moles of EO, and an adduct of bisphenol A with 20 moles of EO), and propylene oxide (hereinafter abbreviated as PO) adducts of bisphenol A (such as an adduct of bisphenol A with 2 moles of PO, an adduct of bisphenol A with 3 moles of PO, and an adduct of bisphenol A with 5 moles of PO), as well as EO or PO adducts of resorcinol.

[0016] The polycarbonate polyol is not particularly limited, and examples thereof include polycarbonate polyols produced by condensing one or more polyhydric alcohols having 2 to 20 carbon atoms with a low molecular weight carbonate compound (for example, a dialkyl carbonate having an alkyl group with 1 to 6 carbon atoms, an alkylene carbonate having an alkylene group with 2 to 6 carbon atoms, and a diaryl carbonate having an aryl group with 6 to 9 carbon atoms) while causing a dealcoholization reaction.

[0017] The polycarbonate polyol is not particularly limited, and examples thereof include polyhexamethylene carbonate diol, polypentamethylene carbonate diol, 3-methyl-5-pentane carbonate diol, polytetramethylene carbonate diol, and poly(tetramethylene / hexamethylene) carbonate diol (diols obtained by condensing 1,4-butanediol and 1,6-hexanediol with a dialkyl carbonate while causing a dealcoholization reaction, etc.).

[0018] Commercially available polycarbonate polyols are not particularly limited, and examples thereof include Nipporan 980R [a polycarbonate polyol having Mn=2000 using 1,6-hexanediol, manufactured by Nippon Polyurethane Industry Co., Ltd.], Duranol T6002 [a polycarbonate polyol having Mn=2000 using 1,6-hexanediol, manufactured by Asahi Kasei Chemicals Corporation], ETERNACOLL UH-300 [a polycarbonate polyol having Mn=3000 using 1,6-hexanediol, manufactured by Ube Industries, Ltd.], ETERNACOLL UH-200 [a polycarbonate polyol having Mn=2000 using 1,6-hexanediol, manufactured by Ube Industries, Ltd.], ETERNACOLL UM-90(1 / 3) [polycarbonate polyol with Mn=900 using 1,4-cyclohexanedimethanol / 1,6-hexanediol = 1 / 3 (molar ratio), manufactured by Ube Industries, Ltd.], Duranol G4672 [polycarbonate polyol with Mn=2000 using 1,4-butanediol / 1,6-hexanediol = 70 / 30 (molar ratio), manufactured by Asahi Kasei Chemicals Corporation], Duranol T5652 [polycarbonate polyol with Mn=2000 made from 1,5-pentanediol / 1,6-hexanediol = 50 / 50 (molar ratio), manufactured by Asahi Kasei Chemicals Corporation], T4672 [polycarbonate polyol with Mn=2000 made from 1,4-butanediol / 1,6-hexanediol = 90 / 10 (molar ratio), manufactured by Asahi Kasei Chemicals Corporation], Kuraray Polyol C-2090 [polycarbonate polyol with Mn=2000 made from 3-methyl-1,5-pentanediol / 1,6-hexanediol = 90 / 10 (molar ratio), manufactured by Kuraray Co., Ltd.], Kuraray Polyol C-3090 [polycarbonate polyol with Mn=3000 made from 3-methyl-1,5-pentanediol / 1,6-hexanediol, manufactured by Kuraray Co., Ltd.], Kuraray Polyol C-2050 [polycarbonate polyol having Mn=2000 using 3-methyl-1,5-pentanediol / 1,6-hexanediol=50 / 50 (molar ratio), manufactured by Kuraray Co., Ltd.].

[0019] The polyester polyol is not particularly limited, but examples thereof include condensation type polyester polyol, polylactone polyol, castor oil polyol, and the like.

[0020] The condensation type polyester polyol is not particularly limited, but examples thereof include polyester polyols obtained by dehydration condensation of a polycarboxylic acid having 4 to 20 carbon atoms and a polyhydric alcohol having 2 to 20 carbon atoms, and polyester polyols obtained by dehydration condensation of an ester-forming derivative of a polycarboxylic acid having 4 to 20 carbon atoms and a polyhydric alcohol having 2 to 20 carbon atoms.

[0021] The polyhydric alcohol having 2 to 20 carbon atoms is not particularly limited, and examples thereof include dihydric alcohols such as ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,4-butanediol, 1,6-hexanediol, cyclohexanedimethanol, 3-methylpentanediol, diethylene glycol, neopentyl glycol, 1,4-bis(hydroxymethyl)cyclohexane, 1,4-bis(hydroxyethyl)benzene, and 2,2-bis(4,4'-hydroxycyclohexyl)propane; trihydric alcohols such as glycerin and trimethylolpropane; and tetrahydric to octahydric alcohols such as pentaerythritol, diglycerin, α-methylglucoside, sorbitol, xylitol, mannitol, dipentaerythritol, glucose, fructose, and sucrose.

[0022] Furthermore, the polycarboxylic acid having 4 to 20 carbon atoms or its ester-forming derivative is not particularly limited, and examples thereof include aliphatic dicarboxylic acids (succinic acid, adipic acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, etc.), alicyclic dicarboxylic acids (dimer acid, etc.), aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid, etc.), trivalent or higher polycarboxylic acids (trimellitic acid, pyromellitic acid, etc.), anhydrides thereof (succinic anhydride, maleic anhydride, phthalic anhydride, trimellitic anhydride, etc.), acid halides thereof (adipic acid dichloride, etc.), low-molecular-weight alkyl esters thereof (dimethyl succinate, dimethyl phthalate, etc.), and mixtures thereof.

[0023] The polylactone polyol is not particularly limited, but examples thereof include polyaddition products of lactones to the above-mentioned polyhydric alcohols having 2 to 20 carbon atoms, and examples of lactones include lactones having 4 to 12 carbon atoms (e.g., γ-butyrolactone, γ-valerolactone, and ε-caprolactone).Specific examples of polylactone polyols include polycaprolactone diol, polyvalerolactone diol, and polycaprolactone triol.

[0024] The castor oil-based polyol is not particularly limited, but examples include castor oil and polyol, or modified castor oil modified with an AO having 2 to 12 carbon atoms. Modified castor oil can be produced by transesterification of castor oil and polyol and / or AO addition. Examples of castor oil-based polyols include castor oil, trimethylolpropane-modified castor oil, pentaerythritol-modified castor oil, and EO adducts of castor oil (number of added moles: 4 to 30).

[0025] The AO having 2 to 12 carbon atoms is not particularly limited, but examples thereof include EO, PO, 1,2-, 2,3-, or 1,3-butylene oxide, tetrahydrofuran, 3-methyltetrahydrofuran, α-olefin oxide, styrene oxide, and epihalohydrin (epichlorohydrin, etc.).

[0026] The polyolefin polyol is not particularly limited, but examples thereof include polybutadiene polyol, hydrogenated polybutadiene polyol, polyisoprene polyol, hydrogenated polyisoprene polyol, and hydroxyl group-modified polyolefins that can be obtained by reacting an amino alcohol with an acid-modified polyolefin obtained by modifying a polyolefin with an unsaturated (poly)carboxylic acid (anhydride), as described in, for example, JP 2018-076428 A.

[0027] Commercially available polyolefin polyols are not particularly limited, but examples thereof include the NISSO-PB G series (polybutadiene polyols manufactured by Nippon Soda Co., Ltd.), the Poly bd series (polybutadiene polyols manufactured by Idemitsu Kosan Co., Ltd.), the NISSO-PB GI series (hydrogenated polybutadiene polyols manufactured by Nippon Soda Co., Ltd.), Polytail H (hydrogenated polybutadiene polyols manufactured by Mitsubishi Chemical Corporation), the Poly ip series (polyisoprene polyols manufactured by Idemitsu Kosan Co., Ltd.), and the EPOL series (hydrogenated polyisoprene polyols manufactured by Idemitsu Kosan Co., Ltd.).

[0028] The diol having a carboxyl group and / or a carboxylate anion group is not particularly limited, and examples thereof include a diol (b1) having one carboxyl group, a diol (b2) having two or more carboxyl groups, and a salt obtained by neutralizing the above diol with a neutralizing agent described below. Examples of the diol (b1) having one carboxyl group include 2,2'-dimethylolpropionic acid, 2,2'-dimethylolbutanoic acid, 2,2'-dimethylolbutyric acid, and 2,2'-dimethylolvaleric acid. An example of the diol (b2) having two or more carboxyl groups is tartaric acid.

[0029] The neutralizing agent for the diols (b1) and (b2) is not particularly limited, but examples thereof include ammonia, amine compounds having 1 to 20 carbon atoms, and alkali metal hydroxides (sodium hydroxide, potassium hydroxide, lithium hydroxide, etc.).

[0030] Here, examples of the amine compound having 1 to 20 carbon atoms include primary amines such as monomethylamine, monoethylamine, monobutylamine, monoethanolamine, and 2-amino-2-methyl-1-propanol; secondary amines such as dimethylamine, diethylamine, dibutylamine, diethanolamine, and N-methyldiethanolamine; and tertiary amines such as trimethylamine, triethylamine, dimethylethylamine, and triethanolamine.

[0031] Among these, from the viewpoint of the drying property of the resulting polyurethane resin aqueous dispersion and the water resistance of the resulting film, preferred are amine compounds having a low vapor pressure at 25°C, and more preferred are ammonia, monomethylamine, monoethylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, and dimethylethylamine.

[0032] Of the diols having a carboxyl group and / or a carboxylate anion group, preferred are diols (b1) having one carboxyl group and salts obtained by neutralizing (b1) with a neutralizing agent, and more preferred are 2,2'-dimethylolpropionic acid, 2,2'-dimethylolbutanoic acid, salts obtained by neutralizing 2,2'-dimethylolpropionic acid with a neutralizing agent, and salts obtained by neutralizing 2,2'-dimethylolbutanoic acid with a neutralizing agent.

[0033] The low molecular weight polyol other than polycyclic aliphatic diols is not particularly limited, and examples thereof include polyhydric alcohols having 2 to 20 carbon atoms other than polycyclic aliphatic diols. Examples of polyhydric alcohols having 2 to 20 carbon atoms other than polycyclic aliphatic diols include dihydric alcohols such as ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,4-butanediol, 1,6-hexanediol, cyclohexanedimethanol, 3-methylpentanediol, diethylene glycol, neopentyl glycol, 1,4-bis(hydroxymethyl)cyclohexane, and 1,4-bis(hydroxyethyl)benzene, trihydric alcohols such as glycerin and trimethylolpropane, and tetrahydric to octahydric alcohols such as pentaerythritol, diglycerin, and dipentaerythritol.

[0034] Polyol component Molar average hydroxyl equivalent From the viewpoint of abrasion resistance, , good The molecular weight is preferably 200 or less, more preferably 60 to 200, and even more preferably 60 to 100. Molar average hydroxyl equivalent The number average molecular weight of each polyol component used is Divide by the number of hydroxyl groups in the molecule to get the molar ratio It is an averaged value. The Mn of the polyol in the present invention is measured by gel permeation chromatography (GPC) using polyethylene glycol as a standard. However, the Mn of the low-molecular-weight polyol is a calculated value from the chemical formula.

[0035] The number average molecular weight (Mn) of the polyol component in the present invention can be measured by gel permeation chromatography, for example, under the following conditions. Apparatus: "Waters Alliance 2695" [Waters] Column: "Guardcolumn Super HL" (1 column), "TSKgel SuperH2000, TSKgel SuperH3000, TSKgel SuperH4000 (all manufactured by Tosoh Corporation) connected together" Sample solution: 0.25% by weight tetrahydrofuran solution Solution injection volume: 10μL Flow rate: 0.6ml / min Measurement temperature: 40℃ Detector: Refractive index detector Reference material: Standard polyethylene glycol

[0036] The polyisocyanate component in the present invention contains an aromatic isocyanate and an aliphatic isocyanate as essential components from the viewpoints of abrasion resistance and dispersibility in an aqueous medium. The polyisocyanate components may be used alone, in combination of two or more, or in combination with a polyisocyanate component other than the aromatic isocyanate and the aliphatic isocyanate.

[0037] The aromatic isocyanate is not particularly limited, but examples thereof include aromatic polyisocyanates having 8 to 26 carbon atoms.

[0038] The aromatic polyisocyanate having 8 to 26 carbon atoms is not particularly limited, and examples thereof include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate (tolylene diisocyanate will be abbreviated as TDI hereinafter), crude TDI, 4,4'- or 2,4'-diphenylmethane diisocyanate (diphenylmethane diisocyanate will be abbreviated as MDI hereinafter), crude MDI, polyaryl polyisocyanate, 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatodiphenylmethane, 1,5-naphthalene diisocyanate, 4,4',4"-triphenylmethane triisocyanate, and m- or p-isocyanatophenylsulfonyl isocyanate.

[0039] The aliphatic isocyanate is not particularly limited, but examples thereof include aliphatic polyisocyanates having 4 to 22 carbon atoms and alicyclic polyisocyanates having 8 to 18 carbon atoms.

[0040] The aliphatic polyisocyanate having 4 to 22 carbon atoms is not particularly limited, and examples thereof include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (hereinafter abbreviated as HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethyl caproate, bis(2-isocyanatoethyl)fumarate, bis(2-isocyanatoethyl)carbonate, and 2-isocyanatoethyl-2,6-diisocyanatohexanoate.

[0041] The alicyclic polyisocyanate having 8 to 18 carbon atoms is not particularly limited, but examples thereof include isophorone diisocyanate (hereinafter abbreviated as IPDI), 4,4'-dicyclohexylmethane diisocyanate (hereinafter abbreviated as hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, bis(2-isocyanatoethyl)-4-cyclohexene-1,2-dicarboxylate, and 2,5- or 2,6-norbornane diisocyanate.

[0042] The polyisocyanate component other than the above polyisocyanate component is not particularly limited, and examples thereof include aromatic aliphatic polyisocyanates having 10 to 18 carbon atoms, modified products of these polyisocyanates, and modified products of aromatic isocyanates and aliphatic isocyanates.

[0043] The aromatic aliphatic polyisocyanate having 10 to 18 carbon atoms is not particularly limited, but examples thereof include m- or p-xylylene diisocyanate and α,α,α',α'-tetramethylxylylene diisocyanate.

[0044] The modified polyisocyanate is not particularly limited, and examples thereof include modified polyisocyanates (such as those containing a urethane group, a carbodiimide group, an allophanate group, a urea group, a biuret group, a uretdione group, a uretoimine group, an isocyanurate group, or an oxazolidone group; those having a free isocyanate group content of 8 to 33% by weight, preferably 10 to 30% by weight, and particularly 12 to 29% by weight), such as modified MDI (such as urethane-modified MDI, carbodiimide-modified MDI, and trihydrocarbyl phosphate-modified MDI), urethane-modified TDI, biuret-modified HDI, isocyanurate-modified HDI, and isocyanurate-modified IPDI.

[0045] Of the polyisocyanate components, from the viewpoint of the abrasion resistance of the polyurethane resin (U), aromatic polyisocyanates having 8 to 18 carbon atoms are preferred, more preferably TDI or MDI, and even more preferably 4,4'-MDI. Also, from the viewpoint of the solubility of the polyurethane resin (U) in the polymerization solvent and the dispersibility in the aqueous medium, alicyclic polyisocyanates having 8 to 18 carbon atoms are preferred, more preferably IPDI.

[0046] When the polyurethane resin (U) is obtained by reacting the polyol component with the polyisocyanate component, a chain extender and a reaction terminator may be used for the purpose of controlling the molecular weight.

[0047] The chain extender is not particularly limited, and examples thereof include water, aliphatic polyamines having 2 to 36 carbon atoms [alkylenediamines such as ethylenediamine and hexamethylenediamine; poly(n=2 to 6) alkylene(carbon number 2 to 6) poly(n=3 to 7) amines such as diethylenetriamine, dipropylenetriamine, dihexylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and hexaethyleneheptamine], alicyclic polyamines having 6 to 20 carbon atoms (1,3- or 1,4-diaminocyclohexane, 4,4'- or 2,4'-dicyclohexylmethanediamine, and isopropyl alcohol), and the like. Examples of suitable chain extenders include aromatic polyamines having 6 to 20 carbon atoms (1,3- or 1,4-phenylenediamine, 2,4- or 2,6-tolylenediamine, 4,4'- or 2,4'-methylenebisaniline, etc.), heterocyclic polyamines having 3 to 20 carbon atoms (2,4-diamino-1,3,5-triazine, piperazine, N-aminoethylpiperazine, etc.), hydrazine or a derivative thereof (dibasic acid dihydrazide, for example, adipic acid dihydrazide, etc.), and amino alcohols having 2 to 20 carbon atoms (e.g., ethanolamine, diethanolamine, 2-amino-2-methylpropanol, triethanolamine). One chain extender may be used alone, or two or more may be used in combination.

[0048] The reaction terminator is not particularly limited, and examples thereof include monoalcohols having 1 to 20 carbon atoms (methanol, ethanol, butanol, octanol, decanol, dodecyl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, etc.), and monoamines having 1 to 20 carbon atoms (mono- or di-alkylamines such as monomethylamine, monoethylamine, monobutylamine, dibutylamine, monooctylamine, etc., and mono- or di-alkanolamines such as monoethanolamine, diethanolamine, diisopropanolamine, etc.). One type of reaction terminator may be used alone, or two or more types may be used in combination.

[0049] From the viewpoints of abrasion resistance and dispersibility of resin particles, the weight proportion of the polycyclic aliphatic diol in the polyurethane resin (U) is preferably 10 to 50% by weight, more preferably 15 to 40% by weight, and even more preferably 25 to 40% by weight, based on the total weight of the polyol component and the polyisocyanate component.

[0050] From the viewpoint of abrasion resistance, the total weight proportion of the polyisocyanate component in the polyurethane resin (U) is preferably 40% by weight or more, more preferably 40 to 70% by weight, and even more preferably 50 to 70% by weight, based on the total weight of the polyol component and the polyisocyanate component.

[0051] The total weight proportion of the aromatic isocyanate is preferably 25 to 60% by weight based on the total weight of the polyol component and the polyisocyanate component, from the viewpoints of abrasion resistance, solubility in the polymerization solvent, and dispersibility of the resin particles.

[0052] From the viewpoints of abrasion resistance, solubility in the polymerization solvent, and dispersibility of resin particles, the total weight proportion of the aromatic polyisocyanate in the polyurethane resin (U) is preferably 25 to 65% by weight, more preferably 30 to 60% by weight, based on the total weight of the polyol component and the polyisocyanate component.

[0053] The total weight proportion of the aliphatic isocyanate is preferably 0.5 to 30% by weight based on the total weight of the polyol component and the polyisocyanate component, from the viewpoints of abrasion resistance, solubility in the polymerization solvent, and dispersion stability in water.

[0054] From the viewpoints of solubility in the polymerization solvent and dispersion stability in water, the total weight proportion of the aliphatic polyisocyanate in the polyurethane resin (U) is preferably 0.5 to 30% by weight, more preferably 1 to 25% by weight, based on the total weight of the polyol component and the polyisocyanate component.

[0055] The acid value of the polyurethane resin (U) in the present invention is preferably 15 to 45 mgKOH / g from the viewpoints of the dispersion stability of the polyurethane resin aqueous dispersion, the viscosity of the printing ink, and the water resistance of the dried resin film. It is preferably 15 to 30 mgKOH / g. If the acid value is 15 mgKOH / g or more, the polyurethane resin (U) has good dispersion stability in the polyurethane resin aqueous dispersion, and clogging is unlikely to occur even at high temperatures. On the other hand, if the acid value is 45 mgKOH / g or less, the polyurethane resin is unlikely to swell in water, and the printing ink is unlikely to thicken. Furthermore, the water resistance of the resulting recorded matter can be maintained at a good level.

[0056] The acid value of the polyurethane resin (U) can be changed, for example, by adjusting the content of a skeleton derived from a diol having a carboxyl group and / or a carboxylate anion group (an acid group-containing polyol such as dimethylolpropionic acid).

[0057] The acid value of the polyurethane resin (U) can be measured by the method described in JIS K 0070:1992 (potentiometric titration method).

[0058] The aqueous polyurethane resin dispersion of the present invention may contain multiple types of polyurethane resin (U). The total content of the polyurethane resin (U) in the aqueous polyurethane resin dispersion is preferably 1.0% by weight or more and 65.0% by weight or less, and more preferably 20.0% by weight or more and 65.0% by weight or less.

[0059] The volume average particle diameter (Dv) of the polyurethane resin aqueous dispersion, as measured by a light scattering measurement method, is preferably 10 to 120 nm, more preferably 20 to 60 nm. When the volume average particle diameter (Dv) is 10 nm or more, the polyurethane resin aqueous dispersion has an appropriate viscosity and good handleability, and when it is 120 nm or less, the dispersion stability is good.

[0060] The volume average particle size (Dv) of the polyurethane resin aqueous dispersion as measured by a light scattering measurement method can be controlled by the content of carboxyl groups and / or carboxylate anion groups, the amount of neutralizing agent and dispersant, and the type and dispersing conditions of the dispersing machine used in the dispersing step. The volume average particle diameter (Dv) can be measured using a light scattering particle size distribution analyzer ("LA950 V2" manufactured by Horiba, Ltd.).

[0061] From the viewpoint of the water resistance of a dried film obtained from the aqueous polyurethane resin dispersion, the aqueous polyurethane resin dispersion of the present invention is preferably a self-emulsifying aqueous dispersion that does not use a dispersant (H).

[0062] On the other hand, when dispersing the polyurethane resin (U) in an aqueous medium, a dispersant (H) may be used. Examples of such dispersants (H) include nonionic surfactants (h1), anionic surfactants (h2), cationic surfactants (h3), amphoteric surfactants (h4), and other emulsifying dispersants (h5). The dispersants (H) may be used alone or in combination of two or more.

[0063] The nonionic surfactant (h1) is not particularly limited, and examples thereof include AO-addition type nonionic surfactants and polyhydric alcohol-type nonionic surfactants. Examples of AO-addition types include EO adducts of aliphatic alcohols having 10 to 20 carbon atoms, EO adducts of phenols, EO adducts of nonylphenols, EO adducts of alkylamines having 8 to 22 carbon atoms, and EO adducts of polyoxypropylene glycols. Examples of polyhydric alcohol-type surfactants include fatty acid (8 to 24 carbon atoms) esters of polyhydric (tri- to octahydric or higher) alcohols (2 to 30 carbon atoms) (e.g., glycerin monostearate, glycerin monooleate, sorbitan monolaurate, sorbitan monooleate, etc.) and alkyl (4 to 24 carbon atoms) poly(degree of polymerization 1 to 10) glycosides.

[0064] The anionic surfactant (h2) is not particularly limited, and examples thereof include ether carboxylic acids having a hydrocarbon group having 8 to 24 carbon atoms or salts thereof [sodium lauryl ether acetate and (poly)oxyethylene (number of moles added: 1 to 100) sodium lauryl ether acetate, etc.]; sulfates or ether sulfates having a hydrocarbon group having 8 to 24 carbon atoms or salts thereof [sodium lauryl sulfate, (poly)oxyethylene (number of moles added: 1 to 100) sodium lauryl sulfate, (poly)oxyethylene (number of moles added: 1 to 100) triethanolamine lauryl sulfate, and (poly)oxyethylene (number of moles added: 1 to 100) sodium coconut oil fatty acid monoethanolamide sulfate, etc.]; sulfonates having a hydrocarbon group having 8 to 24 carbon atoms [sodium dodecylbenzenesulfonate, etc.]; sulfosuccinates having one or two hydrocarbon groups each having 8 to 24 carbon atoms; phosphate esters or ether phosphate esters having a hydrocarbon group each having 8 to 24 carbon atoms and their salts [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 each having 8 to 24 carbon atoms [such as sodium laurate and triethanolamine laurate]; and acylated amino acid salts having a hydrocarbon group each 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. ] are some examples.

[0065] The cationic surfactant (h3) is not particularly limited, and examples thereof 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.].

[0066] The amphoteric surfactant (h4) is not particularly limited, and examples thereof include betaine-type amphoteric surfactants (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, etc.) and amino acid-type amphoteric surfactants (sodium β-laurylaminopropionate, etc.).

[0067] Other emulsifying dispersants (h5) are not particularly limited, but examples thereof include polyvinyl alcohol, starch and its derivatives, cellulose derivatives such as carboxymethyl cellulose, methyl cellulose, and hydroxyethyl cellulose, carboxyl group-containing (co)polymers such as polysodium acrylate, and emulsifying dispersants having urethane groups or ester groups described in U.S. Pat. No. 5,906,704 [for example, polycaprolactone polyol and polyether diol linked with polyisocyanate].

[0068] The dispersant (H) may be added at any time after the urethanization reaction of the polyurethane resin (U), before the water-dispersing step of the polyurethane resin (U), during the water-dispersing step, or after the water-dispersing step. However, from the viewpoint of the dispersibility of the polyurethane resin (U) and the stability of the aqueous dispersion, it is preferable to add the dispersant (H) before or during the water-dispersing step.

[0069] Examples of methods for producing the aqueous polyurethane resin dispersion of the present invention include the following methods [1] and [2].

[0070] [1] A method in which a polyol component, a polyisocyanate component, and optionally a chain extender and a reaction terminator are reacted in one or more stages in the presence or absence of an organic solvent (S) to produce a polyurethane resin (U), and if necessary, the carboxyl groups are converted into salts with a neutralizing agent such as triethylamine, followed by dispersing the resulting product in an aqueous medium, and then, if necessary, distilling off the organic solvent (S).

[0071] [2] A method in which a polyol component and a polyisocyanate component are reacted in one stage or multiple stages in the presence or absence of an organic solvent (S) to produce a urethane prepolymer (P) having an isocyanate group, and then, if necessary, the carboxyl groups in the prepolymer (P) are converted into salts with a neutralizing agent such as triethylamine, and the salts are dispersed in an aqueous medium, and a chain extender and / or a reaction terminator are reacted with the isocyanate groups in the prepolymer (P), and then, if necessary, the organic solvent (S) is distilled off.

[0072] Of the methods [1] and [2], the method [2] is preferred from the viewpoints of the dispersion stability of the polyurethane resin (U) and the mechanical strength of the dried film.

[0073] The reaction temperature when producing the polyurethane resin (U) or aqueous polyurethane resin dispersion in the method [1], and the urethane prepolymer (P) in the method [2] is preferably 60 to 120° C., more preferably 60 to 110° C., and particularly preferably 60 to 100° C., from the viewpoint of suppressing side reactions. The production time can be appropriately selected depending on the equipment used, but is generally preferably 1 minute to 100 hours, more preferably 3 minutes to 30 hours, and particularly preferably 5 minutes to 20 hours.

[0074] The organic solvent (S) is selected from solvents that are substantially non-reactive with isocyanate groups, and examples thereof include ketone solvents (e.g., acetone and methyl ethyl ketone), ester solvents (e.g., ethyl acetate, dibasic acid ester (DBE)), ether solvents (e.g., tetrahydrofuran), amide solvents (e.g., N,N-dimethylformamide and N-methylpyrrolidone), and aromatic hydrocarbon solvents (e.g., toluene). These organic solvents (S) may be used alone or in combination of two or more. In addition, the aqueous medium in the present invention means water or a mixture of water and an organic solvent (S).

[0075] The organic solvent (S) is preferably an organic solvent having a boiling point of less than 100° C., such as acetone, methyl ethyl ketone, ethyl acetate, and tetrahydrofuran. The use of an organic solvent with a boiling point of 100°C or higher is undesirable because it is difficult to completely remove the organic solvent from the aqueous medium, and the organic solvent remains in the aqueous dispersion, generating organic solvent during drying.Furthermore, the organic solvent tends to remain in the film, which is undesirable because it causes changes in the mechanical properties of the film over time.

[0076] From the viewpoints of odor, stability over time, environmental impact, and safety, the content of the organic solvent (S) in the aqueous polyurethane resin dispersion is preferably 1% by weight or less, more preferably 0.8% by weight or less, and particularly preferably 0.5% by weight or less, based on the weight of the aqueous polyurethane resin dispersion.

[0077] In the urethanization reaction in the above methods [1] and [2], a known urethanization catalyst or the like can be used as needed to accelerate the reaction. The amount of the urethanization catalyst added is preferably 0.001 to 3% by weight, more preferably 0.005 to 2% by weight, and particularly preferably 0.01 to 1% by weight, based on the weight of the polyurethane resin (U) or prepolymer (P). is.

[0078] Examples of the urethanization catalyst include metal catalysts [tin-based catalysts (trimethyltin laurate, trimethyltin hydroxide, dimethyltin dilaurate, dibutyltin diacetate, dibutyltin dilaurate, stannous octoate, dibutyltin maleate, etc.), lead-based catalysts (lead oleate, lead 2-ethylhexanoate, lead naphthenate, lead octenate, etc.), cobalt-based catalysts (cobalt naphthenate, etc.), bismuth-based catalysts {bismuth tris(2-ethylhexanoate), etc.} and mercury-based catalysts (phenylmercury propionate, etc.)], amine catalysts [triethylenediamine, tetramethylethylenediamine, tetramethylhexylenediamine, diazabicycloalkene {1 ,8-diazabicyclo[5.4.0]-7-undecene}, etc.; carbonates or organic acid salts (formates, etc.) of dialkylaminoalkylamines {dimethylaminoethylamine, dimethylaminopropylamine, diethylaminopropylamine, dibutylaminoethylamine, dimethylaminooctylamine, dipropylaminopropylamine, etc.} or heterocyclic aminoalkylamines [2-(1-aziridinyl)ethylamine, 4-(1-piperidinyl)-2-hexylamine, etc.]; N-methylmorpholine, N-ethylmorpholine, triethylamine, diethylethanolamine, dimethylethanolamine, etc.], and mixtures of two or more thereof.

[0079] The apparatus for dispersing the polyurethane resin (U) or its organic solvent solution in the above method [1], or the urethane prepolymer (P) or its organic solvent solution in the above method [2] in water is not particularly limited, but it is preferable to use a rotary dispersion mixer, an ultrasonic disperser, or a kneader, and among these, a rotary dispersion mixer, which has particularly excellent dispersion ability, is more preferable.

[0080] Examples of rotary dispersion mixers include mixers having general stirring blades such as Maxblend and helical blades, TK Homomixer (manufactured by Primix Corporation), Clearmix (manufactured by M Technique Co., Ltd.), Filmix (manufactured by Primix Corporation), Ultra Turrax (manufactured by IKA Corporation), Ebara Milder (manufactured by Ebara Corporation), Cavitron (manufactured by Eurotech), and Biomixer (manufactured by Nippon Seiki Co., Ltd.).

[0081] The solids concentration (content of components other than volatile components) of the aqueous polyurethane resin dispersion is preferably 20 to 65% by weight, more preferably 25 to 55% by weight, from the viewpoint of ease of handling of the aqueous polyurethane resin dispersion. The solids concentration can be obtained by spreading about 1 g of the aqueous dispersion thinly on a Petri dish, accurately weighing it, heating it at 130°C for 45 minutes using a circulating constant temperature dryer, accurately weighing the weight, and calculating the ratio (percentage) of the remaining weight after heating to the weight before heating.

[0082] From the viewpoint of handleability, the viscosity of the aqueous polyurethane resin dispersion at 25° C. is preferably 5,000 mPa·s or less, more preferably 1,000 mPa·s or less. The viscosity can be measured using a BL-type viscometer.

[0083] From the viewpoint of dispersion stability, the pH of the aqueous polyurethane resin dispersion at 25° C. is preferably 2 to 12, more preferably 4 to 10. The pH can be measured using a pH Meter M-12 (manufactured by Horiba, Ltd.).

[0084] The aqueous polyurethane resin dispersion of the present invention is an aqueous polyurethane resin dispersion for inkjet inks, and when used as an inkjet ink, it produces a dried film with excellent abrasion resistance. Furthermore, even when an inkjet ink using the aqueous polyurethane resin dispersion of the present invention is applied to a non-permeable recording medium such as PET or OPP, it produces a dried film with excellent abrasion resistance. Therefore, the aqueous polyurethane resin dispersion of the present invention is preferably used for inkjet printing on flexible packaging. Flexible packaging printing refers to printing on packaging materials made of flexible materials, such as thin, flexible materials such as plastic film and aluminum foil, and these materials may be used alone or in combination. Packaging materials printed on flexible packaging are used, for example, as bags for food, medicine, etc.

[0085] The printing ink (L) containing the aqueous polyurethane resin dispersion contains a colorant, a moisturizing agent, a penetrating agent, water, and other additives in addition to the aqueous polyurethane resin dispersion.

[0086] Coloring materials include dyes and pigments. The dye is not particularly limited, and reactive dyes, vat dyes, naphthol dyes, sulfide dyes, direct dyes, acid dyes, metal complex dyes, disperse dyes, cationic dyes, etc. can be selected depending on the medium used.

[0087] Examples of pigments include inorganic pigments (e.g., white pigments, black pigments, gray pigments, red pigments, brown pigments, yellow pigments, green pigments, blue pigments, purple pigments, and metallic pigments) and organic pigments (e.g., natural organic pigments, synthetic organic pigments, nitroso pigments, nitro pigments, pigment-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, and phthalocyanine pigments).

[0088] Among these coloring materials, pigments are preferred. One type of coloring material may be used alone, or two or more types may be used in combination. The content of the coloring material is preferably 50% by weight or less, more preferably 30% by weight or less, based on the weight of the printing ink (L).

[0089] The moisturizer is not particularly limited, but examples thereof include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, pentamethylene glycol, trimethylene glycol, 2-butene-1,4-diol, 2-ethyl-1,3-hexanediol, 2-methyl-2,4-pentanediol, tripropylene glycol, polyethylene glycols having an Mn of 2,000 or less, 1,3-propylene glycol, isopropylene glycol, isobutylene glycol, glycerin, mesoerythritol, pentaerythritol, 2-pyrrolidone, N-methyl-2-pyrrolidone, and N-ethyl-2-pyrrolidone. One moisturizer may be used alone, or two or more may be used in combination.

[0090] The penetrating agent is not particularly limited, but examples thereof include glycol ethers (ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol mono-t-butyl ether, triethylene glycol monobutyl ether, 1-methyl-1-methoxybutanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, propylene glycol monobutyl ether, and dipropylene glycol monobutyl ether), and aliphatic diols having 4 to 8 carbon atoms (1,2-pentanediol and 1,2-hexanediol). organic solvents such as 1,2-alkyldiols such as hexanediol, and straight-chain alcohols such as 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, and 1,8-octanediol; acetylene glycol surfactants; acetylene alcohol surfactants; ether surfactants such as polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene alkyl ether, and polyoxyalkylene alkyl ether; ester surfactants such as polyoxyethylene oleic acid, polyoxyethylene oleic acid ester, polyoxyethylene distearate ester, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, and polyoxyethylene stearate; silicone surfactants such as dimethylpolysiloxane;Examples of the penetrating agent include surfactants such as fluorine-based surfactants such as fluorine alkyl esters and perfluoroalkyl carboxylates. One penetrating agent may be used alone, or two or more penetrating agents may be used in combination.

[0091] The water is not particularly limited, but examples thereof include pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, and distilled water, as well as ultrapure water from which ionic impurities have been removed as much as possible. Furthermore, the use of water sterilized by ultraviolet irradiation or the addition of hydrogen peroxide can prevent the growth of bacteria and fungi when the inkjet ink composition is stored for a long period of time.

[0092] Other additives include chelating agents, preservatives, pH adjusters, etc. Examples of chelating agents include ethylenediaminetetraacetate (EDTA), ethylenediamine nitrilotriacetate, hexametaphosphate, pyrophosphate, metaphosphate, etc.

[0093] Preservatives include sodium benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, and 1,2-dibenzinthiazolin-3-one.

[0094] Examples of pH adjusters include potassium dihydrogen phosphate, disodium hydrogen phosphate, sodium hydroxide, lithium hydroxide, potassium hydroxide, ammonia, diethanolamine, triethanolamine, triisopropanolamine, potassium carbonate, sodium carbonate, and sodium hydrogen carbonate.

[0095] The recording medium used in printing with the printing ink (L) is not particularly limited, but examples thereof include non-permeable recording media and permeable recording media.

[0096] Non-permeable recording media are not particularly limited, but examples thereof include resin media such as polycarbonate, hard vinyl chloride, soft vinyl chloride, polystyrene, expanded polystyrene, polymethyl methacrylate, polypropylene, polyethylene, and polyethylene terephthalate, and metal media such as glass and stainless steel. Furthermore, permeable recording media are not particularly limited, but examples thereof include paper media such as fine paper, art paper, coated paper, and cast-coated paper.

[0097] Among these, from the viewpoint of abrasion resistance, non-permeable recording media are preferred as recording media for the printing ink (L), and resin recording media are more preferred, and resin recording media are suitable for printing on flexible packaging. Flexible packaging printing refers to printing on flexible recording media such as resin films, either alone or in laminated layers, and printed materials produced using flexible packaging printing are used to package food, household goods, etc. [Example]

[0098] 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. Examples 4, 5, 10 and 11 shall be read as Reference Examples, respectively.

[0099] Example 1 A simple pressurized reaction apparatus equipped with a stirrer and a heater was charged with 35.9 parts of tricyclo[5.2.1.0(2,6)]decane dimethanol as the polycyclic aliphatic diol, 4.5 parts of 2,2-dimethylolpropionic acid as a polyol component having a carboxyl group, 37.4 parts of 4,4-diphenylmethane diisocyanate as an aromatic polyisocyanate component, 22.1 parts of isophorone diisocyanate as an aliphatic isocyanate, and 54 parts of methyl ethyl ketone as an organic solvent for the reaction, and the mixture was stirred at 70°C for 12 hours to carry out a urethanization reaction, producing a methyl ethyl ketone solution of a urethane prepolymer (P1) having an isocyanate group. Next, 2.9 parts of triethylamine as a neutralizer was added to the resulting methyl ethyl ketone solution of urethane prepolymer (P1), and the mixture was homogenized. Then, 176 parts of ion-exchanged water was added as an aqueous medium while stirring at 200 rpm to disperse the polyurethane prepolymer in water. The resulting dispersion was heated to 50°C and stirred for 4 hours to allow for chain extension by the amino groups formed by the reaction of the water with the isocyanate groups. The dispersion was then heated to 60°C under reduced pressure to distill off the methyl ethyl ketone. Water was then added to adjust the solids concentration to 30% by weight, yielding aqueous polyurethane resin dispersion (Q-1). The raw materials and amounts used are shown in Table 1.

[0100] <Examples 2 to 12, Comparative Examples 1 and 3> Aqueous polyurethane resin dispersions (Q-2 to Q-12, Q'-1, 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 1 and that a chain extender shown in Table 1 was added after dispersing the polyurethane prepolymer in water. The raw materials and amounts used are shown in Table 1.

[0101] <Comparative Example 2> A simple pressure reactor equipped with a stirrer and a heater was charged with 19.0 parts of ETERNACOLL UH-200 [manufactured by Ube Industries, Ltd.] as polycarbonate diol, 15.8 parts of 1,4-butanediol as low molecular weight diol, 4.5 parts of 2,2-dimethylolpropionic acid as a polyol component having a carboxyl group, 60.6 parts of 4,4-diphenylmethane diisocyanate as an aromatic polyisocyanate component, and 54 parts of methyl ethyl ketone as an organic solvent for the reaction, and the mixture was stirred at 70°C for 2 hours to carry out a urethane-forming reaction. However, the reactant had poor solubility in the organic solvent and precipitated, so dispersion into water was discontinued.

[0102] In Table 1, "Polyol component Molar average hydroxyl equivalent " is the number average molecular weight of the polyol component Divide by the number of hydroxyl groups in the molecule to get the molar ratio This is an averaged value. The "total weight proportion of aromatic isocyanate" is a value (% by weight) based on the total weight of the polyol component and the polyisocyanate component. The "total weight proportion of aliphatic isocyanate" is a value (% by weight) based on the total weight of the polyol component and the polyisocyanate component. The "volume average particle size" is the volume average particle size (Dv) value (nm) of an aqueous polyurethane resin dispersion measured by a light scattering measurement method.

[0103] [Table 1]

[0104] <Production of Printing Inks (L-1) to (L-12), (L'-1) and (L'-3)> 2.7 parts of the polyurethane resin aqueous dispersions (Q-1) to (Q-12), (Q'-1), and (Q'-3) obtained in Examples 1 to 12 and Comparative Examples 1 and 3, 2.5 parts of a pigment [carbon black aqueous dispersion {"Aqua-Black 162" manufactured by Tokai Carbon Co., Ltd., solids concentration 20% by weight}], 1.0 part of glycerin as a humectant, 0.1 part of triethylene glycol, 0.1 part of 1,2-hexanediol as a penetrant, and 3.6 parts of water were charged into a container and mixed for 10 minutes to prepare printing inks (L-1) to (L-12) and comparative printing inks (L'-1) and (L'-3).

[0105] The liquid permeability and abrasion resistance of the printing inks (L-1) to (L-12), (L'-1) and (L'-3) were evaluated by the following methods. The results are shown in Table 1.

[0106] <Printing ink permeability> 100g of printing ink was filtered using the vacuum filtration method, and the amount of ink that passed through the filter until it clogged was measured. If the entire amount was passed through, the amount of ink that passed was considered to be 100g. The more ink that was passed through, the less likely the nozzles were to clog during printing, and the more stable the printing could be. Clogging is mainly caused by particles with a large particle size or aggregates of pigment or resin particles due to insufficient dispersion stability. Filter: MF-Millipore SMWP04700 Filtration pressure: 50kPa

[0107] <Method for evaluating the scratch resistance of printing ink (L)> Printing inks (L-1) to (L-12), (L'-1), and (L'-3) were applied to polypropylene film (OPP) [Toyobo Co., Ltd.'s "Pylen P-2161" (thickness: 30 μm)] and polyester film (PET) [Toyobo Co., Ltd.'s "Spet E-5102" (thickness: 12 μm)] using a bar coater so that the thickness after drying was 1 μm. The inks were then dried at 90°C for 10 minutes to prepare test specimens in which polyurethane resin was coated on each resin film. The dried surface of the printed ink on the prepared test specimen was subjected to an abrasion resistance test using a Gakushin-type abrasion fastness tester. In the dry test, a 60mm x 60mm cotton cloth (Kanakin No. 3) attached to the abrader was rubbed 100 times with a load of 200g. In the wet test, the same cotton cloth as used in the dry test was moistened with 0.3g of water and then attached to the abrader, and the abrasion resistance was rubbed 10 times with a load of 200g. After the test, the degree of peeling of the image was visually judged, and the abrasion resistance of the printed ink was evaluated according to the following criteria. ◎: Image retention rate is 70-100% ○: Image retention rate is 50-69% ×: Image retention rate is less than 50% [Industrial Applicability]

[0108] The aqueous polyurethane resin dispersion of the present invention is an aqueous polyurethane resin dispersion for inkjet inks, and is useful as an ink raw material for printing on recording media such as resin media such as polycarbonate, hard PVC, soft PVC, polystyrene, expanded polystyrene, polymethyl methacrylate, polypropylene, polyethylene, and polyethylene terephthalate, paper media such as fine paper, art paper, coated paper, and cast-coated paper, and metal media such as glass and stainless steel. In particular, it is suitable for flexible packaging using recording media such as polypropylene (OPP) and polyethylene terephthalate (PET).

Claims

1. The composition contains a polyurethane resin (U) obtained by reacting a polyol component with a polyisocyanate component, and water, the polyurethane resin (U) is a polyurethane resin having a carboxyl group and / or a carboxylate anion group, the polyol component is a polyol component containing a polycyclic aliphatic diol and a diol having a carboxyl group and / or a carboxylate anion group, the polycyclic aliphatic diol is tricyclodecane dimethanol, and the diol having a carboxyl group and / or a carboxylate anion group is dimethylolpropionic acid, the polyisocyanate component is a polyisocyanate component containing an aromatic isocyanate and an aliphatic isocyanate, the aromatic isocyanate is 4,4'-diphenylmethane diisocyanate and / or tolylene diisocyanate, and the aliphatic isocyanate is isophorone diisocyanate; the total weight percentage of the polycyclic aliphatic diols is 30 to 39.5% by weight based on the total weight of the polyol component and the polyisocyanate component, the total weight percentage of the diols having a carboxyl group and / or a carboxylate anion group is 4.5 to 9.6% by weight based on the total weight of the polyol component and the polyisocyanate component, the total weight percentage of the aromatic isocyanates is 29.3 to 60% by weight based on the total weight of the polyol component and the polyisocyanate component, the total weight percentage of the aliphatic isocyanates is 1.0 to 25% by weight based on the total weight of the polyol component and the polyisocyanate component, and the total weight percentage of the polyisocyanate components is 54.3 to 61.4% by weight based on the total weight of the polyol component and the polyisocyanate component, Aqueous dispersion of polyurethane resin for inkjet inks.

2. 2. The aqueous polyurethane resin dispersion according to claim 1, wherein the molar average hydroxyl equivalent of the polyol component is 200 or less.

3. 3. The aqueous polyurethane resin dispersion according to claim 1, wherein the aromatic isocyanate is 4,4'-diphenylmethane diisocyanate.

4. 4. The aqueous polyurethane resin dispersion according to claim 1, wherein the volume average particle diameter measured by a light scattering measurement method is 10 to 120 nm.

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