Aqueous polyurethane resin dispersion for inkjet

Abstract

To provide a polyurethane resin aqueous dispersion which has blocking resistance and is excellent in adhesion.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 polytetramethylene ether glycol, and the weight ratio of the polytetramethylene ether glycol is 10-70 wt.%. The polyisocyanate component contains isophorone diisocyanate, and the weight ratio of the isophorone diisocyanate is 25-70 wt.%. The polyurethane resin (U) has an acid value of 15-40 mg KOH / g and a urea group content of 0.45 mol / kg or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an aqueous dispersion of a polyurethane resin for inkjet use.

Background Art

[0002] Polyurethane resins are widely used as binder resins for paints, printing inks, adhesives, etc. because they have excellent flexibility, chemical resistance, and mechanical strength. In recent years, due to environmental considerations, there has been an increasing need for water-dispersible polyurethane resins with low VOC in the drying process, and adding water-dispersible polyurethane resins to printing inks has been under consideration. In particular, use in inkjet inks for low-absorbing or non-absorbing recording media is expected in the future. In such applications, high levels of image color development and fastness (such as rub resistance, light resistance, ozone gas resistance, water resistance, etc.) are required. Printed matter printed with pigment ink containing a pigment as a coloring material has high color development because the pigment component is likely to be localized on the surface of the recording medium. The pigment stays on the surface of the recording medium due to evaporation or penetration of the vehicle component that occurs during the process of the ink adhering to the recording medium or after adhesion. However, in pigment ink, since the pigment as a coloring material is likely to be present on the surface of the recording medium, the adhesion and rub resistance of the ink film are particularly important. To improve these properties of printed matter with pigment ink, adding a urethane resin to the ink has been under consideration (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, as non-permeable recording media, there are polar recording media having many polar groups such as polyethylene terephthalate (PET) and nylon, and low-polar recording media having few polar groups such as polypropylene (OPP). For either of these recording media, the ink film is not yet sufficient in terms of an ink that provides excellent properties such as adhesion. An object of the present invention is to provide an aqueous polyurethane resin dispersion for inkjet ink that has anti-blocking properties and is particularly excellent in adhesion (lamination strength) to non-permeable recording media.

Means for Solving the Problems

[0005] As a result of intensive studies, the present inventors have arrived at the present invention. That is, the present invention is an aqueous polyurethane resin dispersion for inkjet ink containing a polyurethane resin (U) obtained by reacting a polyol component and a polyisocyanate component and water, 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 polytetramethylene ether glycol, the weight ratio of the polytetramethylene ether glycol is 10 to 70% by weight based on the total weight of the polyol component and the polyisocyanate component, the polyisocyanate component is a polyisocyanate component containing isophorone diisocyanate, the weight ratio of the isophorone diisocyanate is 25 to 70% by weight based on the total weight of the polyol component and the polyisocyanate component, the acid value of the polyurethane resin (U) is 15 to 40 mgKOH / g, and the content of the urea group in the polyurethane resin (U) is 0.45 mol / kg or less.

Effects of the Invention

[0006] According to the present invention, it becomes possible to provide an aqueous polyurethane resin dispersion that has anti-blocking properties and is particularly excellent in adhesion (lamination strength) to non-permeable recording media.

Modes for Carrying Out the Invention

[0007] The aqueous dispersion of the polyurethane resin of the present invention contains a polyurethane resin (U) obtained by reacting a polyol component and a polyisocyanate component, and water. The polyurethane resin (U) is preferably contained in the aqueous dispersion of the polyurethane resin as polyurethane resin particles composed of the polyurethane resin (U). The polyurethane resin particles are the solid content in a dispersion in which the polyurethane resin particles are dispersed in a dispersion medium. A dispersion in which the dispersion medium is mainly water is called an aqueous dispersion.

[0008] The polyurethane resin (U) in the present invention can be obtained by reacting a polyol component and a polyisocyanate component.

[0009] The polyol component in the present invention contains polytetramethylene ether glycol as an essential component from the viewpoint of adhesion to a recording medium, particularly a polypropylene (OPP) film and a polyethylene terephthalate (PET) film.

[0010] Polytetramethylene ether glycol may be used alone or in combination with other polyol components, and may be used alone or in combination of two or more. The polytetramethylene ether glycol is not particularly limited, and examples thereof include polytetramethylene ether glycol and polytetramethylene ether glycol modified with 3-methyl-tetrahydrofuran. Specific examples of such polytetramethylene ether glycols include PTMG1000 [poly(oxytetramethylene) glycol with Mn = 1000, manufactured by Mitsubishi Chemical Corporation], PTMG2000 [poly(oxytetramethylene) glycol with Mn = 2000, manufactured by Mitsubishi Chemical Corporation], PTMG3000 [poly(oxytetramethylene) glycol with Mn = 3000, manufactured by Mitsubishi Chemical Corporation], PTGL2000 [modified poly(oxytetramethylene) glycol with Mn = 2000, manufactured by Hodogaya Chemical Co., Ltd.], and PTGL3000 [modified poly(oxytetramethylene) glycol with Mn = 3000, manufactured by Hodogaya Chemical Co., Ltd.]. In the present invention, "Mn" means the number average molecular weight.

[0011] The weight ratio of polytetramethylene ether glycol is 10 to 70% by weight, preferably 35 to 70% by weight, and more preferably 45 to 70% by weight, based on the total weight of the polyol component and the polyisocyanate component, from the viewpoints of adhesion to a recording medium, particularly an OPP film, etc. and blocking resistance.

[0012] The other polyol components other than the above are not particularly limited, and examples thereof include high molecular diols (A) excluding polytetramethylene ether glycol, diols (B) having a carboxyl group and / or a carboxylate anion group, and low molecular polyols (C).

[0013] Further, 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 (B) 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).

[0014] The high molecular weight diol (A) is not particularly limited, and examples thereof include polyether polyols other than polytetramethylene ether glycol, polycarbonate polyols, polyester polyols, polyolefin polyols, and the like.

[0015] The polyether polyol other than polytetramethylene ether glycol is not particularly limited, and examples thereof include aliphatic polyether diols and aromatic polyether diols.

[0016] Examples of the aliphatic polyether diol include adducts of alkylene oxides having 2 to 12 carbon atoms (hereinafter abbreviated as AO) to aliphatic polyhydric alcohols having 2 to 20 carbon atoms, and specifically include polyoxyalkylene glycols (such as polyethylene glycol), polyoxypropylene glycols (such as polypropylene glycol), and polyoxyethylene / propylene glycol copolymers.

[0017] Examples of commercially available aliphatic polyether diols include Sunnex PP-2000 [polyoxypropylene glycol with Mn = 2000, manufactured by Sanyo Chemical Industries, Ltd.].

[0018] 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 (EO2 molar adduct of bisphenol A, EO4 molar adduct of bisphenol A, EO6 molar adduct of bisphenol A, EO8 molar adduct of bisphenol A, EO10 molar adduct of bisphenol A, and EO20 molar adduct of bisphenol A, etc.) and propylene oxide (hereinafter abbreviated as PO) adducts of bisphenol A (PO2 molar adduct of bisphenol A, PO3 molar adduct of bisphenol A, and PO5 molar adduct of bisphenol A, etc.), and EO or PO adducts of resorcinol.

[0019] The polycarbonate polyol is not particularly limited. For example, it includes polycarbonate polyols produced by condensing one or more polyhydric alcohols having 2 to 20 carbon atoms with a low molecular weight carbonate compound (e.g., dialkyl carbonate having 1 to 6 carbon atoms in the alkyl group, alkylene carbonate having an alkylene group with 2 to 6 carbon atoms, and diaryl carbonate having an aryl group with 6 to 9 carbon atoms) while carrying out a dealcoholization reaction.

[0020] Such polycarbonate polyols are not particularly limited. For example, they 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 carrying out a dealcoholization reaction, etc.).

[0021] Examples of commercially available polycarbonate polyols include Nipporan 980R [a polycarbonate polyol with Mn = 2000 using 1,6 - hexanediol, manufactured by Nippon Polyurethane Industry Co., Ltd.], Duranol T6002 [a polycarbonate polyol with Mn = 2000 using 1,6 - hexanediol, manufactured by Asahi Kasei Chemicals Corporation], ETERNACOLL UH - 300 [a polycarbonate polyol with Mn = 3000 using 1,6 - hexanediol, manufactured by Ube Industries, Ltd.], ETERNACOLL UH - 200 [a polycarbonate polyol with Mn = 2000 using 1,6 - hexanediol, manufactured by Ube Industries, Ltd.], ETERNACOLL UM - 90(1 / 3) [a polycarbonate polyol with Mn = 900 using 1,4 - cyclohexanedimethanol / 1,6 - hexanediol = 1 / 3 (molar ratio), manufactured by Ube Industries, Ltd.], Duranol G4672 [a polycarbonate polyol with Mn = 2000 using 1,4 - butanediol / 1,6 - hexanediol = 70 / 30 (molar ratio), manufactured by Asahi Kasei Chemicals Corporation], Duranol T5652 [a polycarbonate polyol with Mn = 2000 using 1,5 - pentanediol / 1,6 - hexanediol = 50 / 50 (molar ratio), manufactured by Asahi Kasei Chemicals Corporation], T4672 [a polycarbonate polyol with Mn = 2000 using 1,4 - butanediol / 1,6 - hexanediol, manufactured by Asahi Kasei Chemicals Corporation], Kuraray Polyol C - 2090 [a polycarbonate polyol with Mn = 2000 using 3 - methyl - 1,5 - pentanediol / 1,6 - hexanediol = 90 / 10 (molar ratio), manufactured by Kuraray Co., Ltd.], Kuraray Polyol C - 3090 [a polycarbonate polyol with Mn = 3000 using 3 - methyl - 1,5 - pentanediol / 1,6 - hexanediol, manufactured by Kuraray Co., Ltd.], and Kuraray Polyol C - 2050 [a polycarbonate polyol with Mn = 2000 using 3 - methyl - 1,5 - pentanediol / 1,6 - hexanediol = 50 / 50 (molar ratio), manufactured by Kuraray Co., Ltd.], etc.

[0022] The polyester polyol is not particularly limited, and examples thereof include condensation-type polyester polyols, polylactone polyols, and castor oil-based polyols.

[0023] The condensation-type polyester polyol is not particularly limited, and examples thereof include polyester polyols obtained by dehydration condensation of a polyvalent carboxylic 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 polyvalent carboxylic acid having 4 to 20 carbon atoms and a polyhydric alcohol having 2 to 20 carbon atoms.

[0024] Here, 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, 3-methylpentanediol, diethylene glycol, neopentyl glycol, 1,4-bis(hydroxymethyl)cyclohexane, 1,4-bis(hydroxyethyl)benzene, 2,2-bis(4,4'-hydroxycyclohexyl)propane; trihydric alcohols such as glycerin and trimethylolpropane; and tetra- to octavalent alcohols such as pentaerythritol, diglycerin, α-methylglucoside, sorbitol, xylitol, mannitol, dipentaerythritol, glucose, fructose, and sucrose.

[0025] In addition, the polyvalent carboxylic acid having 4 to 20 carbon atoms or its ester-forming derivative is not particularly limited. For example, aliphatic dicarboxylic acids (such as succinic acid, adipic acid, azelaic acid, sebacic acid, fumaric acid, and maleic acid), alicyclic dicarboxylic acids (such as dimer acid), aromatic dicarboxylic acids (such as phthalic acid, isophthalic acid, and terephthalic acid), trivalent or higher polycarboxylic acids (such as trimellitic acid and pyromellitic acid), anhydrides thereof (such as succinic anhydride, maleic anhydride, phthalic anhydride, and trimellitic anhydride), acid halides thereof (such as adipic acid dichloride), low molecular weight alkyl esters thereof (such as dimethyl succinate and dimethyl phthalate), and mixtures thereof can be mentioned.

[0026] The polylactone polyol is not particularly limited. For example, it is an adduct of lactone to the above polyhydric alcohol having 2 to 20 carbon atoms. Examples of the lactone include lactones having 4 to 12 carbon atoms (such as γ-butyrolactone, γ-valerolactone, and ε-caprolactone). Specific examples of the polylactone polyol include, for example, polycaprolactone diol, polyvalerolactone diol, and polycaprolactone triol.

[0027] The castor oil-based polyol is not particularly limited. For example, it includes castor oil modified with a polyol or an alkylene oxide having 2 to 12 carbon atoms (hereinafter abbreviated as AO). The modified castor oil can be produced by transesterification of castor oil with a polyol and / or addition of AO. Examples of the castor oil-based polyol include castor oil, trimethylolpropane-modified castor oil, pentaerythritol-modified castor oil, and EO adducts of castor oil (the number of added moles is 4 to 30 moles).

[0028] The AO having 2 to 12 carbon atoms is not particularly limited. For example, EO, PO, 1,2-, 2,3-, or 1,3-butylene oxide, tetrahydrofuran, 3-methyl-tetrahydrofuran, α-olefin oxide, styrene oxide, and epihalohydrin (such as epichlorohydrin) can be mentioned.

[0029] The polyolefin polyol is not particularly limited. For example, it includes polybutadiene polyol, hydrogenated polybutadiene polyol, polyisoprene polyol, hydrogenated polyisoprene polyol, and hydroxyl group-modified polyolefin which can be obtained by reacting an acid-modified polyolefin obtained by modifying a polyolefin described in, for example, JP-A-2018-076428 with an unsaturated (poly)carboxylic acid (anhydride) and an amino alcohol.

[0030] Commercially available polyolefin polyols are not particularly limited. For example, they include NISSO-PB G series [polybutadiene polyol, manufactured by Nippon Soda Co., Ltd.], Poly bd series [polybutadiene polyol, manufactured by Idemitsu Kosan Co., Ltd.], NISSO-PB GI series [hydrogenated polybutadiene polyol, manufactured by Nippon Soda Co., Ltd.], Poly tail H [hydrogenated polybutadiene polyol, manufactured by Mitsubishi Chemical Corporation], Poly ip series [polyisoprene polyol, manufactured by Idemitsu Kosan Co., Ltd.], and EPOL series [hydrogenated polyisoprene polyol, manufactured by Idemitsu Kosan Co., Ltd.].

[0031] The diol (B) having a carboxyl group and / or a carboxylate anion group is not particularly limited. For example, it includes a diol (b1) having one carboxyl group, a diol (b2) having two or more carboxyl groups, and salts obtained by neutralizing the above diols with a neutralizing agent described later. The diol (b1) having one carboxyl group is not particularly limited. For example, it includes 2,2'-dimethylolpropionic acid, 2,2'-dimethylolbutanoic acid, 2,2'-dimethylolbutyric acid, and 2,2'-dimethylolvaleric acid.

[0032] In addition, the diol (b2) having two or more carboxyl groups is not particularly limited. For example, it includes tartaric acid.

[0033] The neutralizing agent for the diols (b1) and (b2) is not particularly limited, and examples thereof include ammonia, amine compounds having 1 to 20 carbon atoms, and alkali metal hydroxides (such as sodium hydroxide, potassium hydroxide, and lithium hydroxide).

[0034] Here, the amine compound having 1 to 20 carbon atoms is not particularly limited, and examples thereof 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.

[0035] Among these, from the viewpoints of the drying property of the resulting aqueous polyurethane resin dispersion and the water resistance of the obtained film, preferred are amine compounds having a low vapor pressure at 25°C, more preferably ammonia, monomethylamine, monoethylamine, dimethylamine, diethylamine, trimethyl, triethylamine, and dimethylethylamine.

[0036] Among the diols (B) having a carboxyl group and / or a carboxylate anion group, preferably, they are diols (b1) having one carboxyl group and salts obtained by neutralizing (b1) with a neutralizing agent, more preferably 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.

[0037] Examples of the low molecular weight polyol (C) include polyhydric alcohols having 2 to 20 carbon atoms. Examples of the polyhydric alcohols having 2 to 20 carbon atoms are the same as those described above.

[0038] From the perspective of the mechanical properties of the polyurethane resin (U), the number average molecular weight (Mn) of the polyol component other than the low molecular weight polyol (C) among the polyol components is preferably 300 or more, more preferably 300 to 10,000, and particularly preferably 500 to 6,000. 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.

[0039] The number average molecular weight (Mn) of the polyol component in the present invention can be measured by gel permeation chromatography under, for example, the following conditions. Apparatus: "Waters Alliance 2695" [manufactured by Waters] Column: "Guardcolumn Super H-L" (1 piece), "a combination of one each of TSKgel SuperH2000, TSKgel SuperH3000, and TSKgel SuperH4000 (all manufactured by Tosoh Corporation)" Sample solution: 0.25 wt% tetrahydrofuran solution Solution injection volume: 10 μl Flow rate: 0.6 ml / min Measurement temperature: 40°C Detector: Refractive index detector Reference substance: Standard polyethylene glycol

[0040] In the present invention, the polyisocyanate component contains isophorone diisocyanate as an essential component from the perspective of adhesion to a recording medium, particularly an OPP film and a PET film. Isophorone diisocyanate (hereinafter also referred to as IPDI) may be used alone or in combination with other polyisocyanate components, and one kind may be used alone or two or more kinds may be used in combination.

[0041] The weight ratio of isophorone diisocyanate is 25 to 70% by weight, preferably 25 to 40% by weight, more preferably 28 to 35% by weight, based on the total weight of the polyol component and the polyisocyanate component, from the viewpoints of adhesion to the OPP film and blocking resistance.

[0042] The other polyisocyanate components other than the above isophorone diisocyanate are not particularly limited, and examples thereof include aromatic polyisocyanates having 8 to 26 carbon atoms and having two or more isocyanate groups, aliphatic polyisocyanates having 4 to 22 carbon atoms, alicyclic polyisocyanates having 8 to 18 carbon atoms, araliphatic polyisocyanates having 10 to 18 carbon atoms, and modified products of these polyisocyanates. The polyisocyanate component may be used alone or in combination of two or more.

[0043] The aromatic polyisocyanates having 8 to 26 carbon atoms are not particularly limited, and examples thereof include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate (hereinafter, tolylene diisocyanate is abbreviated as TDI), crude TDI, 4,4'- or 2,4'-diphenylmethane diisocyanate (hereinafter, diphenylmethane diisocyanate is abbreviated as MDI), 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.

[0044] The aliphatic polyisocyanates having 4 to 22 carbon atoms are 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.

[0045] The alicyclic polyisocyanates having 8 to 18 carbon atoms are not particularly limited, and examples thereof include 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. 4,4'-dicyclohexylmethane diisocyanate is also referred to as methylene bis 4,4'-cyclohexylene-diisocyanate.

[0046] The araliphatic polyisocyanates having 10 to 18 carbon atoms are not particularly limited, and examples thereof include m- or p-xylylene diisocyanate and α,α,α',α'-tetramethylxylylene diisocyanate.

[0047] The modified polyisocyanate is not particularly limited. For example, the modified product of the above polyisocyanate (a modified product 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, etc.; a free isocyanate group content of 8 to 33% by weight, preferably 10 to 30% by weight, particularly 12 to 29% by weight), for example, modified MDI (urethane-modified MDI, carbodiimide-modified MDI, and trihydrocarbyl phosphate-modified MDI, etc.), urethane-modified TDI, biuret-modified HDI, isocyanurate-modified HDI, and isocyanurate-modified IPDI, etc. Modified products of polyisocyanates can be mentioned.

[0048] When reacting the above polyol component and polyisocyanate component to obtain the polyurethane resin (U), a chain extender and a reaction terminator may be used for the purpose of controlling the molecular weight.

[0049] 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 (having 2 to 6 carbon atoms) 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, isophoronediamine, etc.), aromatic polyamines having 6 to 20 carbon atoms (1,3- or 1,4-phenylenediamine, 2,4- or 2,6-toluenediamine, 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 its derivatives (dibasic acid dihydrazide such as adipic acid dihydrazide, etc.), and aminoalcohols having 2 to 20 carbon atoms (e.g., ethanolamine, diethanolamine, 2-amino-2-methylpropanol, and triethanolamine). The chain extender may be used alone or in combination of two or more kinds.

[0050] 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 dialkylamines such as monomethylamine, monoethylamine, monobutylamine, dibutylamine, and monooctylamine, and mono- or dialkanolamines such as monoethanolamine, diethanolamine, and diisopropanolamine). The reaction terminator may be used alone or in combination of two or more kinds.

[0051] In the present invention, the acid value of the polyurethane resin (U) is 15 to 40 mgKOH / g, preferably 15 to 30 mgKOH / g, from the viewpoints of the dispersion stability of the aqueous polyurethane resin dispersion, the viscosity of the printing ink, and the water resistance of the dried resin film. If the acid value is 15 mgKOH / g or more, the dispersion stability of the polyurethane resin (U) in the aqueous polyurethane resin dispersion is good, and clogging is less likely to occur even at high temperatures. On the other hand, if the acid value is 40 mgKOH / g or less, the polyurethane resin is less likely to swell in water, and the printing ink is less likely to thicken. Furthermore, the water resistance of the resulting recording can be kept good.

[0052] The acid value of the polyurethane resin (U) can be changed, for example, by adjusting the content of the skeleton derived from the diol (B) having a carboxyl group and / or a carboxylate anion group (acid group-containing polyol such as dimethylolpropionic acid).

[0053] The acid value of the polyurethane resin (U) can be measured by the method (potentiometric titration method) described in JIS K 0070:1992.

[0054] In the present invention, the number average molecular weight (Mn) of the polyurethane resin (U) is preferably 10,000 to 1,000,000 from the viewpoints of the blocking resistance and adhesion of the polyurethane resin (U).

[0055] The number average molecular weight (Mn) of the polyurethane resin (U) can be measured by the same method as the number average molecular weight (Mn) of the above polyol component.

[0056] The content of urea groups in the polyurethane resin (U) in the present invention is 0.45 mol / kg or less. When the content of urea groups is greater than 0.45 mol / kg, coarse particles are likely to be generated, and when used in an inkjet ink, the temporal stability of the ink viscosity and clogging of the inkjet head will occur. Further, by containing urea groups, the adhesion (lamination strength) becomes good. The content of urea groups in the polyurethane resin (U) is preferably 0.3 mol / kg or less, and more preferably 0.1 to 0.3 mol / kg from the viewpoint of antiblocking properties.

[0057] The content of urethane groups in the polyurethane resin (U) in the present invention is preferably 1.0 to 10 mol / kg, more preferably 1.5 to 8.0 mol / kg, and still more preferably 1.8 to 6.0 mol / kg. By the content of urethane groups being within the above range, the generation of coarse particles is suppressed, and the adhesion tends to be further improved.

[0058] In addition, the content of urethane groups and urea groups in the present invention can be calculated from the charged composition of the raw materials. Further, it can also be measured by the following analysis method if necessary. <Method for Measuring Content of Urea Groups and Urethane Groups> The contents of urea groups and urethane groups are calculated from the N atom content quantified by a nitrogen analyzer [ANTEK 7000 (manufactured by ANTEK)] and the ratio of urethane groups to urea groups quantified by 1H-NMR. For the 1H-NMR measurement, it is carried out by the method described in "Structural Study of Polyurethane Resins by NMR: Takeda Research Institute Report 34(2), 224-323(1975)". That is, when measuring 1H-NMR, in the case of using aliphatic isocyanates, the weight ratio of urea groups to urethane groups is measured from the ratio of the integral amount of hydrogen derived from urea groups near a chemical shift of 6 ppm to the integral amount of hydrogen derived from urethane groups near a chemical shift of 7 ppm, and the contents of urethane groups and urea groups are calculated from the weight ratio, the above N atom content, and the allophanate group and burette group contents. When using aromatic isocyanates, the weight ratio of urea groups to urethane groups is calculated from the ratio of the integral amount of hydrogen derived from urea groups near a chemical shift of 8 ppm to the integral amount of hydrogen derived from urethane groups near a chemical shift of 9 ppm, and the content of urea groups is calculated from the weight ratio and the above N atom content.

[0059] The urethane group content of the polyurethane resin (U) in the present invention can be calculated by the following method. It is calculated from the charged composition of the raw materials by the following calculation formula (1) or (2). Calculation formula (1): When the content (mol) of isocyanate groups in the raw materials - the content (mol) of hydroxyl groups in the raw materials < 0 Urethane group content (mol / kg) = content (mol) of isocyanate groups in the raw materials / resin solids (kg) Calculation formula (2): When the content (mol) of isocyanate groups in the raw materials - the content (mol) of hydroxyl groups in the raw materials > 0 Urethane group content (mol / kg) = content (mol) of hydroxyl groups in the raw materials / resin solids (kg)

[0060] The urea group content of the polyurethane resin (U) in the present invention can be calculated by the following method. It is calculated from the charged composition of the raw materials by the following calculation formula (3) or (4). Calculation formula (3): When the isocyanate group content (mol) in the raw material - the hydroxyl group content (mol) in the raw material - the amino group content (mol) of the chain extender > 0 Urea group content (mol / kg) = amino group content (mol) of the chain extender + {[isocyanate group content (mol) in the raw material - hydroxyl group content (mol) in the raw material - amino group content of the chain extender] × 1 / 2} / resin solid content (kg) Calculation formula (4): When the isocyanate group content (mol) in the raw material - the hydroxyl group content (mol) in the raw material - the amino group content (mol) of the chain extender < 0 Urea group content (mol / kg) = [isocyanate group content (mol) in the raw material - hydroxyl group content (mol) in the raw material] / resin solid content (kg)

[0061] The storage modulus G' at 50°C of the film obtained by drying the polyurethane resin aqueous dispersion in the present invention at 105°C for 3 hours is preferably 0.9 to 80 MPa, more preferably 1 to 60 MPa, and still more preferably 3 to 30 MPa from the viewpoints of blocking resistance and adhesion to the recording medium.

[0062] In the present invention, the storage modulus G' of the polyurethane resin (U) can be measured by the following method. Also, the storage modulus G' at 50°C of the film obtained by drying the polyurethane resin aqueous dispersion at 105°C for 3 hours was measured using the following viscoelasticity measuring apparatus. Apparatus: MCR92 (manufactured by Anton Paar) Jig: 8 mm parallel plate Frequency: 11 Hz Strain rate: 0.5% Temperature rising rate: 5°C / min Temperature rising start: 20°C Temperature rising end: 120°C Preparation of a film by drying an aqueous polyurethane resin dispersion: 10 parts of an aqueous polyurethane resin dispersion was poured into a 10 cm × 20 cm × 0.1 cm polypropylene mold in such an amount that the film thickness after water evaporation would be 200 μm, and after heating and drying at 105 °C for 3 hours in a circulating air dryer overnight at room temperature, it was cut into 1 cm × 1 cm pieces to be used as measurement samples.

[0063] In the aqueous polyurethane resin dispersion of the present invention, the polyurethane resin (U) preferably exists as polyurethane resin particles from the viewpoint of adhesion. Further, from the viewpoint of the blocking resistance of an image obtained from an ink using the aqueous polyurethane resin dispersion, it is preferable that the polyurethane resin particles in the aqueous polyurethane resin dispersion contain the anti-blocking agent (E) for ink in the same particle.

[0064] The anti-blocking agent (E) for ink is an additive added to an inkjet ink for the purpose of preventing troubles such as when the surface of a printed matter printed with an inkjet ink overlaps with the unprinted back surface of the next printed matter, or when the printed characters or images stick to the unprinted back surface when the printed matter is stored in a rolled state. It is an additive having a function of reducing the contact area by roughening the surface of the ink coating film or forming a protective layer on the surface by migrating to the surface of the ink coating film.

[0065] The anti-blocking agent (E) for ink can be used as an aqueous dispersion containing the polyurethane resin particles and (E) in the same particle in the aqueous polyurethane resin dispersion. However, it can also be blended and used in the aqueous polyurethane resin dispersion or printing ink as an aqueous dispersion separate from the polyurethane resin particles. Further, when the anti-blocking agent (E) for ink is water-soluble, it can also be blended and used by dissolving it in the aqueous medium of the aqueous polyurethane resin dispersion or printing ink, and these can also be used in combination. From the viewpoint of not inhibiting the dispersion stability of the aqueous dispersions of the resin and the pigment, it is preferable to use it as an aqueous dispersion containing the polyurethane resin particles and the anti-blocking agent (E) for ink in the same particle.

[0066] The anti-blocking agent (E) for ink is not particularly limited, and examples thereof include polyolefin wax, natural wax, aliphatic alcohols having 30 to 50 carbon atoms, fatty acids having 30 to 50 carbon atoms, fluorine-based compounds, silicone-based compounds, aliphatic amides, and polyoxyethylene compounds.

[0067] The polyolefin wax is not particularly limited, and examples thereof include (co)polymers of olefins (such as ethylene, propylene, 1-butene, isobutylene, 1-hexene, 1-dodecene, 1-octadecene, and mixtures thereof) [(including those obtained by (co)polymerization and thermally reduced-molded polyolefins)], oxides of (co)polymers of olefins by oxygen and / or ozone, maleic acid-modified products of (co)polymers of olefins [such as modified products of maleic acid and its derivatives (maleic anhydride, monomethyl maleate, monobutyl maleate, dimethyl maleate, etc.)], copolymers of olefins and unsaturated carboxylic acids [(meth)acrylic acid, itaconic acid, maleic anhydride, etc.] and / or unsaturated carboxylic acid alkyl esters [(alkyl (meth)acrylate esters having 1 to 18 carbon atoms in the alkyl group and alkyl maleate esters having 1 to 18 carbon atoms in the alkyl group, etc.], and Sasol wax.

[0068] The natural wax is not particularly limited, and examples thereof include carnauba wax, montan wax, paraffin wax, and rice wax.

[0069] The aliphatic alcohol having 30 to 50 carbon atoms is not particularly limited, and examples thereof include triacontanol.

[0070] The fatty acid having 30 to 50 carbon atoms is not particularly limited, and examples thereof include triacontane carboxylic acid.

[0071] The fluorine-based compounds are not particularly limited, and examples thereof include polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, and polyvinylidene fluoride.

[0072] The silicone-based compounds are not particularly limited, and examples thereof include lecithin, silicone oil, and silicone wax. Examples of the silicone oil include linear silicone oil, cyclic silicone oil, and modified silicone oil. The linear silicone oil is not particularly limited, and examples thereof include linear dimethyl silicone oils such as tetradecamethylhexasiloxane, hexadecamethylheptasiloxane, and docosamethyl decasiloxane, and branched dimethyl silicone oils such as methyltris(trimethylsiloxy)silane and tetrakis(trimethylsiloxy)silane. The cyclic silicone oil is not particularly limited, and examples thereof include decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, hexadecamethylcyclooctasiloxane, and octadecamethylcyclononasiloxane. The modified silicone oil is not particularly limited, and examples thereof include aryl-modified silicone oils such as alkyl-modified silicone, phenyl-modified silicone, and aralkyl-modified silicone, carboxylic acid ester-modified silicone, alkylene-modified silicone, and polyether-modified silicone.

[0073] The aliphatic amides are not particularly limited, and examples thereof include lauric acid amide and stearic acid amide as saturated fatty acid monoamides, oleic acid amide as an unsaturated fatty acid monoamide, methylene bisstearic acid amide and ethylene biscapric acid amide as saturated fatty acid bisamides, ethylene bisoleic acid amide and hexamethylene bisoleic acid amide as unsaturated fatty acid bisamides, N-stearyl stearic acid amide and N-oleyl oleic acid amide as substituted amides, methylol stearic acid amides and methylol behenic acid amide as methylol amides such as methylol aromatic bisamides, N,N-distearyl isophthalic acid amide, metaxylylene bisstearic acid amide, etc., N,N'-2-hydroxyethyl stearic acid amide and N,N'-ethylene bisoleic acid amide as branched amides, etc.), and coconut oil fatty acid monoethanol amide and lauric acid monoethanol amide as alkanolamides.

[0074] The polyoxyethylene compounds are not particularly limited, and examples thereof include polyoxyethylene alkyl ethers, polyoxyethylene alkenyl ethers, polyoxyethylene mono-fatty acid esters, and polyoxyethylene sorbitan fatty acid esters.

[0075] The polyoxyethylene alkyl ethers are not particularly limited, and examples thereof include polyoxyethylene lauryl ether, polyoxyethylene myristyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, and polyoxyethylene behenyl ether. The polyoxyethylene alkenyl ethers are not particularly limited, and examples thereof include polyoxyethylene tetradecenyl ether, polyoxyethylene hexadecenyl ether, and polyoxyethylene octadecenyl ether. The polyoxyethylene mono-fatty acid ester is not particularly limited, and examples thereof include polyoxyethylene monolaurate, polyoxyethylene monomyristate, polyoxyethylene monopalmitate, polyoxyethylene monostearate, and the like. The polyoxyethylene sorbitan fatty acid ester is not particularly limited, and examples thereof include polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan monoisostearate, polyoxyethylene sorbitan distearate, polyoxyethylene sorbitan tristearate, and the like.

[0076] From the viewpoints of antiblocking property and compatibility with the polyurethane resin, the ink antiblocking agent (E) is preferably a silicone-based compound, an aliphatic amide, or a polyoxyethylene compound, more preferably silicone oil or polyoxyethylene alkyl ether, still more preferably silicone oil, particularly preferably modified silicone oil, and most preferably polyether-modified silicone.

[0077] When the polyurethane resin particles contain the ink antiblocking agent (E), from the viewpoints of antiblocking property and adhesion to the recording medium, it is preferable that the polyurethane resin particles contain the ink antiblocking agent (E) in an amount of 0.1 to 10% by weight based on the weight of the polyurethane resin (U), more preferably 0.5 to 5% by weight, and still more preferably 0.5 to 3% by weight.

[0078] The volume average particle diameter (Dv) of the polyurethane resin particles measured by the light scattering measurement method is preferably 10 to 80 nm, more preferably 20 to 60 nm. When (Dv) is 10 nm or more, the viscosity of the aqueous polyurethane resin dispersion is appropriate and the handleability is good, and when it is 80 nm or less, the dispersion stability is good.

[0079] The volume average particle diameter (Dv) can be controlled by the content of carboxyl groups and / or carboxylate anion groups, the neutralizing agent, the amount of the dispersant, and the type and dispersion conditions of the dispersing machine used in the dispersion step. The volume average particle diameter (Dv) can be measured with a light scattering particle size distribution measuring device ["LA950 V2" manufactured by Horiba, Ltd.].

[0080] From the viewpoint of the water resistance of the dried film obtained from the polyurethane resin aqueous dispersion, the polyurethane resin aqueous dispersion of the present invention is preferably a self-emulsifying type aqueous dispersion that does not use a dispersant (H).

[0081] Examples of the dispersant (H) when dispersing the polyurethane resin (U) in an aqueous medium include nonionic surfactants (h1), anionic surfactants (h2), cationic surfactants (h3), amphoteric surfactants (h4), and other emulsifying dispersants (h5). (H) may be used alone or in combination of two or more.

[0082] 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 the AO addition type include EO adducts of aliphatic alcohols having 10 to 20 carbon atoms, EO adducts of phenol, EO adducts of nonylphenol, EO adducts of alkylamines having 8 to 22 carbon atoms, and EO adducts of polyoxypropylene glycol. Examples of the polyhydric alcohol type include fatty acid (having 8 to 24 carbon atoms) esters of polyhydric (3 to 8 valent or more) alcohols (having 2 to 30 carbon atoms) (such as glycerin monostearate, glycerin monooleate, sorbitan monolaurate, and sorbitan monooleate), and alkyl (having 4 to 24 carbon atoms) poly (degree of polymerization 1 to 10) glycosides.

[0083] The anionic surfactant (h2) is not particularly limited. For example, it includes ether carboxylic acids or their salts having a hydrocarbon group with 8 to 24 carbon atoms [sodium lauryl ether acetate and sodium (poly)oxyethylene (1 to 100 moles added) lauryl ether acetate, etc.]; sulfate esters or ether sulfate esters having a hydrocarbon group with 8 to 24 carbon atoms and their salts [sodium lauryl sulfate, sodium (poly)oxyethylene (1 to 100 moles added) lauryl sulfate, triethanolamine (poly)oxyethylene (1 to 100 moles added) lauryl sulfate, and sodium (poly)oxyethylene (1 to 100 moles added) coconut fatty acid monoethanolamine sulfate, etc.]; sulfonates having a hydrocarbon group with 8 to 24 carbon atoms [sodium dodecylbenzenesulfonate, etc.]; sulfosuccinates having one or two hydrocarbon groups with 8 to 24 carbon atoms; phosphate esters or ether phosphate esters having a hydrocarbon group with 8 to 24 carbon atoms and their salts [sodium lauryl phosphate and sodium (poly)oxyethylene (1 to 100 moles added) lauryl ether phosphate, etc.]; fatty acid salts having a hydrocarbon group with 8 to 24 carbon atoms [sodium laurate and triethanolamine laurate, etc.]; and acylated amino acid salts having a hydrocarbon group with 8 to 24 carbon atoms [sodium coconut fatty acid methyl taurate, sodium coconut fatty acid sarcosine, triethanolamine coconut fatty acid sarcosine, triethanolamine N-coconut fatty acid acyl-L-glutamate, sodium N-coconut fatty acid acyl-L-glutamate, and sodium lauroylmethyl-β-alanine, etc.].

[0084] The cationic surfactant (h3) is not particularly limited. For example, it includes quaternary ammonium salt types [stearyl trimethyl ammonium chloride, behenyl trimethyl ammonium chloride, distearyl dimethyl ammonium chloride, and ethyl sulfate lanolin fatty acid aminopropyl ethyldimethyl ammonium, etc.] and amine salt types [diethylaminoethylamide lactate stearate, dilaurylamine hydrochloride, and oleylamine lactate, etc.].

[0085] Although the amphoteric surfactant (h4) is not particularly limited, examples thereof include betaine-type amphoteric surfactants [such as coconut oil fatty acid amide propyl dimethylaminoacetic acid betaine, lauryl dimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, lauryl hydroxysulfobetaine, and sodium lauroyl amidoethyl hydroxyethyl carboxymethyl betaine hydroxypropyl phosphate, etc.] and amino acid-type amphoteric surfactants [such as sodium β-lauryl aminopropionate, etc.].

[0086] Although the other emulsifying and dispersing agent (h5) is not particularly limited, 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 sodium polyacrylate, and emulsifying and dispersing agents having a urethane group or an ester group described in U.S. Patent No. 5,906,704 [for example, those obtained by linking polycaprolactone polyol and polyether diol with polyisocyanate], etc.

[0087] The dispersing agent (H) may be added at any time after the urethanization reaction of the polyurethane resin (U), before the water dispersion step of the polyurethane resin (U), during the water dispersion step, or after the water dispersion. However, from the viewpoints of the dispersibility of the polyurethane resin (U) and the stability of the aqueous dispersion, it is preferably added before the water dispersion step or during the water dispersion step.

[0088] Examples of the method for producing the aqueous dispersion of the polyurethane resin of the present invention include the following methods [1] and [2], etc.

[0089] [1] A method in which a polyol component, a polyisocyanate component, and, if necessary, a chain extender and a reaction terminator are reacted in one or multiple steps in the presence or absence of an organic solvent (S) to produce a polyurethane resin (U), and, if necessary, a carboxyl group is converted into a salt with a neutralizing agent, dispersed in an aqueous medium, and then, if necessary, the organic solvent (S) is distilled off.

[0090] [2] A method of reacting a polyol component and a polyisocyanate component in one or multiple steps in the presence or absence of an organic solvent (S) to produce a urethane prepolymer (P) having isocyanate groups, and then, if necessary, neutralizing the carboxyl groups in the prepolymer (P) with a neutralizing agent to disperse them as salts in an aqueous medium, reacting a chain extender and / or a reaction terminator with the isocyanate groups in the prepolymer (P), and then, if necessary, distilling off the organic solvent (S).

[0091] Among the methods of [1] and [2], from the viewpoints of the dispersion stability of the polyurethane resin (U) and the mechanical strength of the dried film, the method of [2] is preferred.

[0092] The reaction temperature for producing the polyurethane resin (U) in the method of [1] and the urethane prepolymer (P) in the method of [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 generally 1 minute to 100 hours is preferred, more preferably 3 minutes to 30 hours, and particularly preferably 5 minutes to 20 hours.

[0093] The organic solvent (S) is selected from solvents that are substantially non-reactive with isocyanate groups, such as 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), etc. 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 the organic solvent (S).

[0094] Preferred as the organic solvent (S) are organic solvents having a boiling point of less than 100 °C, such as acetone, methyl ethyl ketone, ethyl acetate, and tetrahydrofuran, etc. When using an organic solvent with a boiling point of 100°C or higher, it becomes difficult to completely remove only the organic solvent from the aqueous medium, and it remains in the aqueous dispersion, generating the organic solvent during drying, which is not preferable. Also, the organic solvent tends to remain in the film, and the mechanical properties of the film change over time, which is not preferable.

[0095] From the viewpoints of odor, stability over time, environmental load, and safety, the content of the organic solvent (S) in the polyurethane resin aqueous 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 polyurethane resin aqueous dispersion.

[0096] In the urethanization reaction in the methods [1] and [2] above, in order to accelerate the reaction, a known urethanization catalyst or the like can be used if necessary. The addition amount of the urethanization catalyst 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.

[0097] Examples of the urethanization catalyst include metal catalysts [tin-based catalysts (such as trimethyltin laurate, trimethyltin hydroxide, dimethyltin dilaurate, dibutyltin diacetate, dibutyltin dilaurate, stannous octoate, and dibutyltin maleate), lead-based catalysts (such as lead oleate, lead 2-ethylhexanoate, lead naphthenate, and lead octenoate), cobalt-based catalysts (such as cobalt naphthenate), bismuth-based catalysts {such as bismuth tris(2-ethylhexanoate)}, and mercury-based catalysts (such as phenylmercury propionate), etc.], amine catalysts [triethylenediamine, tetramethylethylenediamine, tetramethylhexylenediamine, diazabicycloalkene {1,8-diazabicyclo[5.4.0]-7-undecene}, etc.; carbonates or organic acid salts (such as formates) of dialkylaminoalkylamines {such as dimethylaminoethylamine, dimethylaminopropylamine, diethylaminopropylamine, dibutylaminoethylamine, dimethylaminooctylamine, and dipropylaminopropylamine} or heterocyclic aminoalkylamines [such as 2-(1-aziridinyl)ethylamine and 4-(1-piperidinyl)-2-hexylamine], etc.; N-methylmorpholine, N-ethylmorpholine, triethylamine, diethylethanolamine, and dimethylethanolamine, etc.], and mixtures of two or more of these.

[0098] The apparatus for dispersing the polyurethane resin (U) or its organic solvent solution in the method of [1] above, or the urethane prepolymer (P) or its organic solvent solution in the method of [2] above in water is not particularly limited, but it is preferable to use a rotary dispersion mixer, an ultrasonic disperser, or a kneader, and among them, a rotary dispersion mixer having particularly excellent dispersion ability is more preferable.

[0099] Examples of the rotary dispersion mixer include mixers having common stirring blades such as Max Blend and helical blades, TK Homomixer [manufactured by Primix Corporation], Clear Mix [manufactured by M Technique Co., Ltd.], Filmix [manufactured by Primix Corporation], Ultra Turrax [manufactured by IKA Corporation], Ebara Mildar [manufactured by Ebara Corporation], Cavitron [manufactured by Eurotech], and Biomixer [manufactured by Nippon Seiki Co., Ltd.].

[0100] The solid content 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 solid content concentration can be obtained by thinly spreading about 1 g of the aqueous dispersion on a Petri dish, precisely weighing it, then precisely weighing the weight after heating at 130 °C for 45 minutes using a circulating constant-temperature dryer, and calculating the ratio (percentage) of the residual weight after heating to the weight before heating.

[0101] 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, from the viewpoint of handleability. The viscosity can be measured using a BL-type viscometer.

[0102] The pH of the aqueous polyurethane resin dispersion at 25 °C is preferably 2 to 12, more preferably 4 to 10, from the viewpoint of dispersion stability. The pH can be measured using a pH Meter M-12 [manufactured by Horiba, Ltd.].

[0103] The polyurethane resin aqueous dispersion of the present invention is a polyurethane resin aqueous dispersion for inkjet ink, and it is preferable that when used as inkjet ink, it has good adhesion to the recording medium. Further, from the viewpoints of adhesion of the image (lamination strength) and blocking resistance, it is preferably used as an inkjet ink for flexible packaging printing. Flexible packaging printing refers to printing on a packaging material composed of a flexible material. Examples of the packaging material include thin and flexible materials such as plastic films, aluminum foils, and papers, and a single one or a plurality of them laminated together may be used. The packaging material subjected to flexible packaging printing is used, for example, as a bag for foods, pharmaceuticals, etc.

[0104] The printing ink (L) containing the polyurethane resin aqueous dispersion contains a coloring material, a humectant, a penetrant, water, and other additives in addition to the polyurethane resin aqueous dispersion.

[0105] Examples of the coloring material include dyes and pigments. Although not particularly limited as the dye, depending on the medium to be used, reactive dyes, vat dyes, naphthol dyes, sulfur dyes, direct dyes, acid dyes, metal complex dyes, disperse dyes, cationic dyes, etc. can be selected.

[0106] Examples of the pigment include inorganic pigments (for example, white pigments, black pigments, gray pigments, red pigments, brown pigments, yellow pigments, green pigments, blue pigments, purple pigments, and metallic pigments) and organic pigments (for example, natural organic pigments, synthetic organic pigments, nitroso pigments, nitro pigments, pigment dye type azo pigments, azo lakes made from water-soluble dyes, azo lakes made from hardly soluble dyes, lakes made from basic dyes, lakes made from acid dyes, xanthene lakes, anthraquinone lakes, pigments from vat dyes, and phthalocyanine pigments).

[0107] Among these coloring materials, pigments are preferable. The coloring material may be used alone or in combination of two or more. 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).

[0108] The humectant is not particularly limited. For example, 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 glycol with Mn of 2,000 or less, 1,3-propylene glycol, isopropyl glycol, isobutylene glycol, glycerin, meso-erythritol, pentaerythritol, 2-pyrrolidone, N-methyl-2-pyrrolidone, and N-ethyl-2-pyrrolidone can be mentioned. The humectant may be used alone or in combination of two or more.

[0109] The penetration agent is not particularly limited. For example, 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, etc.) and aliphatic diols having 4 to 8 carbon atoms (1,2-alkyl diols such as 1,2-pentanediol and 1,2-hexanediol, and linear alcohols such as 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol and 1,8-octanediol, etc.) and other organic solvents; acetylene glycol-based surfactants; acetylene alcohol-based surfactants; ether-based surfactants such as polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene alkyl ether, polyoxyalkylene alkyl ether, etc.; ester-based surfactants such as polyoxyethylene oleic acid, polyoxyethylene oleic acid ester, polyoxyethylene distearic acid ester, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate and polyoxyethylene stearate, etc.; silicone-based surfactants such as dimethylpolysiloxane, etc.;Examples of the surfactant include fluorosurfactants such as fluoroalkyl esters and perfluoroalkyl carboxylates. The penetrant may be used alone or in combination of two or more. ;

[0110] The water is not particularly limited. For example, pure water such as ion-exchanged water, ultrafiltration water, reverse osmosis water, and distilled water, and water with ionic impurities removed as much as possible such as ultrapure water can be mentioned. Further, when using water sterilized by ultraviolet irradiation or addition of hydrogen peroxide, etc., generation of bacteria and fungi can be prevented when the inkjet ink composition is stored for a long time.

[0111] Examples of other additives include chelating agents, preservatives, and pH adjusters. Examples of the chelating agent include ethylenediaminetetraacetate (EDTA), nitrilotriacetate of ethylenediamine, hexametaphosphate, pyrophosphate, or metaphosphate.

[0112] Examples of the preservative include sodium benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, and 1,2-dibenzisothiazolin-3-one.

[0113] Examples of the pH adjuster 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.

[0114] The recording medium used in printing with the printing ink (L) is not particularly limited. For example, non-permeable recording media and permeable recording media can be mentioned.

[0115] The non - permeable recording medium is not particularly limited, and examples thereof include resin media such as polycarbonate, rigid PVC, soft PVC, polystyrene, expanded polystyrene, polymethyl methacrylate, polypropylene, polyethylene, polyethylene terephthalate, nylon, etc., and metal substrates such as glass and stainless steel.

[0116] The permeable recording medium is not particularly limited, and examples thereof include paper media such as fine paper, art paper, coated paper, cast coated paper, etc.

[0117] Among these, as the recording medium for the printing ink (L), a non - permeable recording medium is preferable from the viewpoint of adhesion, more preferably a resin medium, and further, from the viewpoints of adhesion (lamination strength) and anti - blocking property, the resin medium is suitable for flexible packaging printing.

[0118] Note that flexible packaging printing is to print on a flexible recording medium such as a resin film alone or laminated, and the printed matter subjected to flexible packaging printing is used for packaging foods, daily necessities, etc.

Examples

[0119] Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited thereto. Hereinafter, unless otherwise specified, "parts" means parts by weight.

[0120] <Production Example 1> Into a reaction apparatus equipped with a stirrer, a reflux pipe, and a heating device, 150 parts of methylhydrogen silicone oil (number - average molecular weight 1500, functional group equivalent 500 g / mol), 150 parts of an ethylene oxide 12 - mole adduct of allyl alcohol, and 100 parts of isopropanol as a reaction organic solvent were charged, and 0.15 ml of a solution of H2PtCl6 of 1 mol in isopropanol was charged as a catalyst. After heating under reflux for 1 hour, isopropanol was distilled off under reduced pressure at 110 ° C to obtain a polyether - modified silicone with a number - average molecular weight of 3000.

[0121] <Example 1> Into a simple pressure reactor equipped with a stirrer and a heating device, 67.6 parts of PTMG2000 [manufactured by Mitsubishi Chemical Corporation] as polytetramethylene ether glycol, 2.8 parts of 1,4-butanediol as a low molecular weight diol, 4.5 parts of 2,2-dimethylolpropionic acid as a polyol component having a carboxyl group in the side chain, 25.1 parts of isophorone diisocyanate as a polyisocyanate component, and 54 parts of methyl ethyl ketone as a reaction organic solvent were charged, and stirred at 70 °C for 12 hours to carry out a urethanization reaction to produce a methyl ethyl ketone solution of a urethane prepolymer (P1) having an isocyanate group. Next, 3.4 parts of triethylamine as a neutralizing agent was added to the obtained methyl ethyl ketone solution of the urethane prepolymer (P1) and homogenized, and then 263 parts of ion-exchanged water as an aqueous medium was added while stirring at 200 rpm to disperse the polyurethane prepolymer in water. The obtained dispersion was heated to 50 °C and stirred for 4 hours to carry out a chain extension reaction with water, and further heated to 60 °C under reduced pressure to distill off methyl ethyl ketone. Thereafter, water was added to adjust the solid content concentration to 30% by weight to obtain an aqueous dispersion (Q-1) of a polyurethane resin.

[0122] <Example 2> Aqueous dispersion (Q-2) of a polyurethane resin was obtained in the same manner as in Example 1 except that the amounts of the raw materials used were changed to those shown in Table 1.

[0123] <Examples 3 to 11> Aqueous dispersions (Q-3 to Q-11) of a polyurethane resin were obtained in the same manner as in Example 1 except that the raw materials used and the amounts used were changed to those shown in Table 1, and after dispersing the polyurethane prepolymer in water, the chain extender shown in Table 1 was added.

[0124] <Example 12> Into a simple pressure reactor equipped with a stirrer and a heating device, 16.0 parts of PTMG2000 [manufactured by Mitsubishi Chemical Corporation] as polytetramethylene ether glycol, 17.8 parts of polycarbonate diol ETERNACOLL UH-200 [manufactured by Ube Industries, Ltd.], 12.2 parts of 1,4-butanediol as a low molecular weight diol, 4.5 parts of 2,2-dimethylolpropionic acid as a polyol component having a carboxyl group in the side chain, 47.6 parts of isophorone diisocyanate as a polyisocyanate component, and 54 parts of methyl ethyl ketone as a reaction organic solvent were charged, and the mixture was stirred at 70 °C for 12 hours to conduct a urethanization reaction, thereby producing a methyl ethyl ketone solution of a urethane prepolymer (P12) having an isocyanate group. Next, 8.0 parts of the polyether-modified silicone obtained in Production Example 1 as an anti-blocking agent for ink and 3.4 parts of triethylamine as a neutralizing agent were added to the methyl ethyl ketone solution of the obtained urethane prepolymer (P12) and homogenized. Then, while stirring at 200 rpm, 262 parts of ion-exchanged water as an aqueous medium was added to disperse the polyurethane prepolymer in water. To the obtained dispersion, 6.3 parts of a 10 wt% aqueous solution of ethylenediamine as a chain extender was added, and the mixture was heated to 50 °C and stirred for 4 hours to conduct an extension reaction. Further, it was heated to 60 °C under reduced pressure to distill off methyl ethyl ketone. Thereafter, water was added to adjust the solid content concentration to 30 wt%, thereby obtaining an aqueous dispersion (Q-12) of a polyurethane resin containing an anti-blocking agent for ink in the same particles.

[0125] <Examples 13 and 14> Except that the raw materials used and the amounts used were changed to those described in Table 1, polyurethane resin aqueous dispersions (Q-13, Q-14) were obtained in the same manner as in Example 1.

[0126] <Comparative Examples 1 to 6> Except that the raw materials used and the amounts used were changed to those described in Table 1, polyurethane resin aqueous dispersions (Q'-1) and (Q'-6) were obtained in the same manner as in Example 1.

[0127] The compositions of the respective raw materials in Table 1 are as follows. · PTMG2000: Polytetramethylene ether glycol with Mn = 2,000 [manufactured by Mitsubishi Chemical Corporation] · PTMG1000: Polytetramethylene ether glycol with Mn = 1,000 [manufactured by Mitsubishi Chemical Corporation] · Sunnex PP-2000: Polyoxypropylene glycol with Mn = 2,000 [manufactured by Sanyo Chemical Industries, Ltd.] · ETERNACOLL UH-200: Polycarbonate diol with Mn = 2,000 [manufactured by Ube Industries, Ltd.]

[0128]

Table 1

[0129] <Manufacture of Printing Inks (L-1) to (L-14) and (L’-1) to (L’-6)>[[]] 2.7 parts of the polyurethane resin aqueous dispersions (Q-1) to (Q-14) or (Q’-1) to (Q’-6) obtained in Examples 1 to 14 or Comparative Examples 1 to 6, 25 parts of a pigment [carbon black aqueous dispersion {“Aqua-Black162” manufactured by Tokai Carbon Co., Ltd., solid content concentration 20% by weight}], 10 parts of propylene glycol as a humectant, 1.0 part of 1,2-hexanediol as a penetrant, 1.0 part of 2-pyrrolidone, and 63 parts of water were charged into a container and mixed for 10 minutes to prepare printing inks (L-1) to (L-14) and comparative printing inks (L’-1) to (L’-6).

[0130] <Evaluation Method for Adhesion of Printing Ink>[[]] Polypropylene film (OPP) [“Pyren P-2161” manufactured by Toyobo Co., Ltd. (thickness 30 μm)] and polyester film (PET) [“Espert E-5102” manufactured by Toyobo Co., Ltd. (thickness 12 μm)] were each coated with printing inks (L-1) to (L-14) and comparative printing inks (L'-1) to (L'-6) using a bar coater so that the dried thickness would be 1 μm, and dried at 90°C for 10 minutes to produce test pieces with a polyurethane resin coated on each resin film. On the dried film surface of the printing ink of the produced test pieces, cuts were made with a cutter knife at 1 mm width so that 100 (10 × 10) squares could be formed in accordance with JIS K5600-5-6, and a peel test was conducted using a transparent pressure-sensitive adhesive tape, and the number of squares remaining on the recording medium film was counted. The greater the number of remaining squares, the better the adhesion of the printing ink.

[0131] <Evaluation Method for Blocking Resistance and Adhesion (Lamination Strength) of Printing Inks> Polypropylene film (OPP) [“Pyren P-2161” manufactured by Toyobo Co., Ltd. (thickness 30 μm)] and polyester film (PET) [“Espert E-5102” manufactured by Toyobo Co., Ltd. (thickness 12 μm)] were printed on the entire surface with printing inks (L-1) to (L-14) and comparative printing inks (L'-1) to (L'-6) by the inkjet method and then dried at 90°C for 10 minutes. An inkjet printer [PX-105 manufactured by Seiko Epson Corporation] was used for printing. However, for the comparative printing inks (L'-4 to L'-6), clogging of the ink head nozzles was confirmed during printing and printing on the entire surface could not be performed, so the evaluation of adhesion (lamination strength) and blocking resistance was aborted.

[0132] <Blocking Resistance> After coating the printing ink on the entire surface of the resin film, it was cut into 4 cm × 8 cm, and the printed surface of this sample was combined with the untreated surface of an unprinted film of the same size, and pressure was applied at 50°C for 24 hours at 7 kg / cm², and the degree of peeling and the resistance feeling of the printed surface when the film was peeled off were observed. 5 points: No peeling of the ink from the printed matter was observed, and there was no resistance feeling during peeling. 4 points: No ink peeling from the printed matter was observed, but there was a sense of resistance during peeling. 3 points: Ink peeling from the printed matter was observed, but it was less than 10% of the entire printed surface. 2 points: Ink peeling from the printed matter was between 10% and less than 50% of the entire printed area. 1 point: Ink peeling from the printed matter was 50% or more of the printed area. 3 points or more are at the practical level.

[0133] <Adhesion (Lamination Strength)> After applying printing ink to the entire surface of the resin film, a PE film ["T.U.X HC-E" (thickness 25 μm) manufactured by Mitsui Chemicals Toagosei Co., Ltd.] was laminated as a sealant film using a laminating adhesive (Polybond AY-651A / AY-651C two-component type manufactured by Sanyo Chemical Industries, Ltd.). After curing at 40 °C for 24 hours, it was measured using an Instron type tensile testing machine (Autograph manufactured by Shimadzu Corporation).

[0134] The lamination conditions are as follows. · Adhesive: AY-651A / AY-651C / ethyl acetate = 6.7 / 1 / 9.3 (solid content approximately 30%) · Coating: The adhesive was applied to the ink surface using a bar coater #7. · Drying conditions: 10 seconds with warm air (approx. 80 °C) from a dryer. · Lamination: The sealant film was laminated using a laminating tester [manufactured by Tester Sangyo Co., Ltd.]. (Lamination pressure: 0.1 MPa, one rotation, room temperature) · Curing: 40 °C, 24 hours The adhesive strength measurement conditions are as follows. · Sample: 15 mm width · Peeling speed: 50 mm / min

[0135] <Ink Viscosity> In the present invention, the viscosity of the printing ink was measured using the following measuring device and conditions. Device: MCR92 (manufactured by Anton Paar) Jig: 50 mm cone plate Shearing speed: 200 1 / s Measuring temperature: 25°C

[0136] <Liquid permeability of printing ink> 100 g of the printing ink was filtered by the vacuum filtration method, and the liquid passing amount until the filter was blocked was measured. When all the liquid passed through, the liquid passing amount was taken as 100 g. Filter: SMWP04700 manufactured by MF-Millipore Filtration pressure: 50 kPa

Industrial applicability

[0137] The aqueous polyurethane resin dispersion of the present invention is an aqueous polyurethane resin dispersion for inkjet ink, and is useful as an ink raw material for printing using recording media such as resin media such as polycarbonate, rigid PVC, soft PVC, polystyrene, expanded polystyrene, polymethyl methacrylate, polypropylene, polyethylene, polyethylene terephthalate, nylon, etc., paper media such as fine paper, art paper, coated paper, cast coated paper, etc., and inorganic media such as glass and stainless steel.

Claims

1. An aqueous polyurethane resin dispersion for an inkjet ink, which contains a polyurethane resin (U) obtained by reacting a polyol component and a polyisocyanate component, and water, 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 polytetramethylene ether glycol, the weight ratio of the polytetramethylene ether glycol is 10 to 70% by weight based on the total weight of the polyol component and the polyisocyanate component, the polyisocyanate component is a polyisocyanate component containing isophorone diisocyanate, the weight ratio of the isophorone diisocyanate is 25 to 70% by weight based on the total weight of the polyol component and the polyisocyanate component, the acid value of the polyurethane resin (U) is 15 to 30 mgKOH / g, and the content of the urea group in the polyurethane resin (U) is 0.15 to 0.45 mol / kg. An aqueous polyurethane resin dispersion.

2. The aqueous polyurethane resin dispersion according to claim 1, wherein the storage elastic modulus G' at 50°C of the film obtained by drying the aqueous polyurethane resin dispersion at 105°C for 3 hours is 0.9 to 80 MPa.

3. The aqueous polyurethane resin dispersion according to claim 1 or 2, wherein the polyurethane resin (U) is contained in the aqueous polyurethane resin dispersion as polyurethane resin particles composed of the polyurethane resin (U), and the polyurethane resin particles in the aqueous polyurethane resin dispersion contain an anti-blocking agent (E) for ink in the same particles.

4. The aqueous polyurethane resin dispersion according to claim 3, wherein the polyurethane resin particles contain 0.1 to 10% by weight of the anti-blocking agent (E) for ink based on the weight of the polyurethane resin (U).

5. The aqueous polyurethane resin dispersion according to claim 3 or 4, wherein the anti-blocking agent (E) for ink is a polyether-modified silicone.

6. The aqueous polyurethane resin dispersion according to any one of claims 1 to 5, wherein the polyurethane resin (U) is contained in the aqueous polyurethane resin dispersion as polyurethane resin particles composed of the polyurethane resin (U), and the volume average particle diameter of the polyurethane resin particles by a light scattering measurement method is 10 to 80 nm.

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