JP2018154829A - Polyurethane resin-coated pigment water dispersion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyurethane resin-coated pigment water dispersion which is excellent in adhesion to a base material by coating a pigment with a polyurethane resin, and is stably dispersed with time.SOLUTION: A polyurethane resin-coated pigment water dispersion (R) is a water dispersion of a pigment (P) in which a pigment (P0) is coated with a polyurethane resin (U), where the polyurethane resin (U) contains polyol (A) selected from the group consisting of polyester diol (A1), polycarbonate diol (A2) and polyether diol (A3), aliphatic diisocyanate (B1) and/or alicyclic diisocyanate (B2), and diol (D) having a carboxyl group and/or a carboxylate anion group as essential constituent monomers, and the content of the total of the carboxyl group and the carboxylate anion group based on the weight of the polyurethane resin (U) is 4-80 mg/g.SELECTED DRAWING: None

Description

The present invention relates to a urethane resin-coated pigment aqueous dispersion.

Conventionally, methods for dispersing a pigment in water include a method using a surfactant, a method for modifying a hydrophilic group on the surface of the pigment, a method for coating the pigment with a hydrophilic resin, and the like.
Among these, a method of coating with a hydrophilic resin has been studied since the dispersion stability is high and the viscosity of the pigment aqueous dispersion is relatively low. For example, a pigment dispersion coated with an organic polymer compound containing an anionic group (for example, Patent Document 1) or a pigment dispersion surface-treated with a rosin or the like using a resin (for example, Patent Document 2) Etc.
However, when used as an ink or the like, there are problems in that the adhesion to the substrate is insufficient, or that the dispersion state changes with time and the viscosity increases or decreases.

Japanese Patent Laid-Open No. 10-140065 JP 10-36732 A

The present invention has been made in view of the above problems, and an object of the present invention is to cover the ejection stability and aging of an inkjet nozzle because the dispersed particle diameter in the ink is small by coating the pigment with polyurethane resin. Another object of the present invention is to provide an aqueous dispersion of a polyurethane resin-coated pigment that is stably dispersed. Further, when used as an ink, it provides excellent adhesion depending on the type of substrate.

The inventors of the present invention have arrived at the present invention as a result of intensive studies to achieve the above object.
That is, the present invention is an aqueous dispersion of a pigment (P) in which the pigment (P0) is coated with a polyurethane resin (U), and the polyurethane resin (U) is a polyester diol (A1), a polycarbonate diol (A2), And a polyol (A) selected from the group consisting of a polyether diol (A3), an aliphatic diisocyanate (B1) and / or an alicyclic diisocyanate (B2), and a diol having a carboxyl group and / or a carboxylate anion group (D ) As an essential constituent monomer, and a polyurethane resin-coated pigment aqueous dispersion (R) having a carboxylate anion group content of 4 to 80 mg / g based on the weight of the polyurethane resin (U); and this polyurethane resin-coated pigment An aqueous ink containing an aqueous dispersion.

According to the present invention, since the dispersed particle diameter in the ink is a small particle diameter, an aqueous dispersion of a polyurethane resin-coated pigment that can be stably dispersed over time with the ejection stability of the inkjet nozzle can be obtained. Further, by selecting a polyol component, excellent adhesion is provided according to the type of base material when used as an ink.

The polyurethane resin-coated pigment aqueous dispersion (R) in the present invention is an aqueous dispersion of a pigment (P) obtained by coating a pigment (P0) with a polyurethane resin (U), and the polyurethane resin (U) is a polyester diol. (A1), polyol (A) selected from the group consisting of polycarbonate diol (A2) and polyether diol (A3), aliphatic diisocyanate (B1) and / or alicyclic diisocyanate (B2), and carboxyl group and / or Alternatively, the diol (D) having a carboxylate anion group is an essential constituent monomer, and the content of the carboxylate anion group based on the weight of the polyurethane resin (U) is 4 to 80 mg / g.

Examples of the polyol (A) of the present invention used for the polyurethane resin (U) of the present invention include polyester diol (A1), polycarbonate diol (A2), polyether diol (A3), and combinations thereof.

Examples of the polyester diol (A1) of the present invention include condensed polyester diols, polylactone diols, and castor oil-based diols.

The condensed polyester diol is a polyester diol of a dihydric alcohol having a number average molecular weight (Mn) of less than 300 and a dicarboxylic acid having 2 to 10 carbon atoms or an ester-forming derivative thereof.

As the low molecular weight dihydric alcohol, a low molar adduct of a divalent aliphatic dihydric alcohol having an Mn of less than 300 and an alkylene oxide of a divalent phenol having an Mn of less than 300 (hereinafter sometimes abbreviated as AO) can be used.
As AO, ethylene oxide (hereinafter sometimes abbreviated as EO), propylene oxide (hereinafter sometimes abbreviated as PO) 1,2-, 1,3-, 2,3- or 1,4-butylene. Examples include oxides.
Among the low molecular weight dihydric alcohols that can be used in the condensation type polyester polyol, ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexane glycol, bisphenol A EO or PO low mole Adducts and combinations thereof.
As a component of the condensed polyester diol, a trivalent or higher alcohol and a trivalent or higher carboxylic acid or an ester-forming derivative thereof may be included.

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

Specific examples of the condensed polyester polyol include polyethylene adipate diol, polybutylene adipate diol, polyhexamethylene adipate diol, polyhexamethylene isophthalate diol, polyhexamethylene terephthalate diol, polyneopentyl adipate diol, polyethylene propylene adipate diol, polyethylene Butylene adipate diol, polybutylene hexamethylene adipate diol, polydiethylene adipate diol, poly (polytetramethylene ether) adipate diol, poly (3-methylpentylene adipate) diol, polyethylene azelate diol, polyethylene sebacate diol, polybutylene aze Rate diol, polybutylene sebacate diol and poly Oh pliers Rutere terephthalate diol.

As a commercially available product of condensed polyester polyol, Sanester 2610 [polyethylene adipate diol with Mn = 1,000, manufactured by Sanyo Chemical Industries, Ltd.], Sanester 4620 [polytetramethylene adipate diol with Mn = 2,000], Sanester 26
20 [polyethylene adipate diol with Mn = 2,000, manufactured by Sanyo Chemical Industries, Ltd.], Kuraray polyol P-2010 [poly-3-methyl-1,5-pentane adipate diol with Mn = 2,000], Kuraray polyol P-3010 [Poly-3 with Mn = 3,000
-Methyl-1,5-pentaneadipate diol], Kuraray polyol P-6010 [poly-3-methyl-1,5-pentane adipate diol with Mn = 6,000], Kuraray polyol P-2020 [Mn = 2,000. Poly-3-methyl-1,5-pentane terephthalate diol], P-2030 [poly-3-methyl-1,5-pentane isophthalate diol with Mn = 2,000] and the like.

The polylactone diol is a polyadduct of lactone to the low molecular weight dihydric alcohol, and examples of the lactone include lactones having 4 to 12 carbon atoms (for example, γ-butyrolactone, γ-valerolactone and ε-caprolactone). It is done.
Specific examples of the polylactone polyol include polycaprolactone diol, polyvalerolactone diol, and polycaprolactone triol.

The castor oil-based polyol includes castor oil and modified castor oil modified with polyol or AO. Modified castor oil can be produced by transesterification of castor oil and polyol and / or AO addition. Castor oil-based polyols include castor oil, trimethylolpropane-modified castor oil, pentaerythritol-modified castor oil, and EO (4 to 30 mol) adduct of castor oil.

As the polycarbonate diol (A2) of the present invention, the low molecular weight dihydric alcohol and a low molecular carbonate compound (for example, an alkylene carbonate having an alkyl group having 1 to 6 carbon atoms and an alkylene group having 2 to 6 carbon atoms) And a polycarbonate diol produced by condensing a diaryl carbonate having an aryl group having 6 to 9 carbon atoms with a dealcoholization reaction. Two or more low molecular weight dihydric alcohols and alkylene carbonates may be used in combination. The low molecular weight dihydric alcohol may contain a trihydric or higher alcohol.

Specific examples of the polycarbonate diol include polyhexamethylene carbonate diol, polypentamethylene carbonate diol, 3-methyl-5-pentane carbonate diol, polytetramethylene carbonate diol and poly (tetramethylene / hexamethylene) carbonate as aliphatic polycarbonate. Diols (for example, diols obtained by condensing 1,4-butanediol and 1,6-hexanediol with a dealcohol reaction with a dialkyl carbonate) and the like. Examples of the aromatic polycarbonate include poly 1,4-xylylene carbonate diol, bisphenol A type polycarbonate diol, and bisphenol F type polycarbonate diol.

  Commercially available products of polycarbonate diol include Nipponan 980R [polyhexamethylene carbonate diol with Mn = 2,000, manufactured by Nippon Polyurethane Industry Co., Ltd.], Kuraray polyol C-3090 [poly (3-methyl--Mn = 3,000) 5-pentanediol / hexamethylene) carbonate diol], T4672 [poly (tetramethylene / hexamethylene) carbonate diol of Mn = 2,000, manufactured by Asahi Kasei Chemicals Corporation], and the like.

  Examples of the polyether diol (A3) of the present invention include aliphatic polyether diols and aromatic ring-containing polyether diols.

Examples of the aliphatic polyether diol include polyoxyethylene polyol [polyethylene glycol (hereinafter abbreviated as PEG), etc.], polyoxypropylene polyol [polypropylene glycol, etc.], polyoxyethylene / propylene polyol, polytetramethylene ether glycol, and the like. Can be mentioned.

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

Examples of the aromatic polyether diol include an EO adduct of bisphenol A [EO 2 mol adduct of bisphenol A, EO 4 mol adduct of bisphenol A, EO 6 mol adduct of bisphenol A, EO 8 mol adduct of bisphenol A, and bisphenol A. EO 10 mol adduct and bisphenol A EO 20 mol adduct, etc.] and bisphenol A PO adduct [PO2 mol adduct of bisphenol A, PO3 mol adduct of bisphenol A, PO5 mol adduct of bisphenol A, etc.] Examples thereof include a polyol having a bisphenol skeleton and an EO or PO adduct of resorcin.

From the viewpoint of the stability of the polyurethane resin-coated pigment aqueous dispersion, at least one of the polyol (A) of the polyester diol (A1), polycarbonate diol (A2), and polyether diol (A3) has an aromatic ring in the molecule. A polyol is preferred.

When the polyurethane resin-coated pigment aqueous dispersion of the present invention is used as an ink, the adhesion varies depending on the type of the base material with which the image is formed by the inkjet method, but by selecting the type of the polyol (A) High adhesion can be obtained.
For example, polyester diol (A1) has high affinity for coated paper and PET film, and has high cohesion when made into a polyurethane resin, and therefore has high adhesion to the substrate. Since the flexibility after film formation is poor, the adhesion to the fabric is low.
For the same reason, polycarbonate diol (A2) has high adhesion to coated paper and PET film, but has low adhesion to fabric. In addition, the adhesiveness to PET film is superior to the polyester diol, and the adhesiveness to coated paper is inferior.
In polyether diol (A3), since the flexibility after film formation is high, it has excellent adhesion to the fabric. On the other hand, since the cohesive force is low, the adhesion to coated paper and PET film is inferior to that of polyester diol (A1) and polycarbonate diol (A2).

The aliphatic diisocyanate (B1) used for the polyurethane resin (U) of the present invention is an aliphatic diisocyanate having 2 to 18 carbon atoms, the alicyclic diisocyanate (B2) is an alicyclic diisocyanate having 4 to 15 carbon atoms, or the like. Is mentioned.

Examples of the aliphatic diisocyanate (B1) having 2 to 18 carbon atoms include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2- And isocyanatoethyl-2,6-diisocyanatohexanoate.

Examples of the alicyclic diisocyanate (B2) having 4 to 15 carbon atoms include isophorone diisocyanate (IPDI), 4,4-dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), Examples thereof include bis (2-isocyanatoethyl) -4-cyclohexene-1,2-dicarboxylate, 2,5- or 2,6-norbornane diisocyanate.

Of the aliphatic diisocyanate (B1) and alicyclic diisocyanate (B2), IPDI and hydrogenated MDI are preferred from the viewpoint of the mechanical strength and weather resistance of the resulting film.

  The diol (D) having a carboxyl group and / or a carboxylate anion group contains a carboxyl group and a compound having 2 to 10 carbon atoms [dialkylol alkanoic acid (for example, 2,2-dimethylolpropionic acid, 2, 2-dimethylolbutanoic acid, 2,2-dimethylolheptanoic acid and 2,2-dimethyloloctanoic acid)] and the like, and salts obtained by neutralizing these compounds with a neutralizing agent.

Among the diols (D), 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid and these are preferable from the viewpoint of the resin physical properties of the resulting film and the dispersion stability of the aqueous polyurethane resin dispersion. Salts are more preferable, and neutralized salts of 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid with ammonia or an amine compound having 1 to 20 carbon atoms.

In the polyurethane resin (U) in the present invention, a chain extender (H) can be used if necessary. Examples of the chain extender (H) include Mn or a low molecular weight polyol (a2) having a chemical formula of less than 300, water, diamines having 2 to 10 carbon atoms (for example, ethylenediamine, propylenediamine, hexamethylenediamine, isophoronediamine, toluenediamine, and Piperazine), polyalkylene polyamines having 2 to 10 carbon atoms (for example, diethylenetriamine, triethylenetetramine and tetraethylenepentamine), hydrazine or a derivative thereof (dibasic acid dihydrazide such as adipic acid dihydrazide), polyoxygen having 2 to 30 carbon atoms, and the like. Epoxy compounds (for example, 1,6-hexanediol diglycidyl ether, trimethylolpropane polyglycidyl ether, etc.) and amino alcohols having 2 to 10 carbon atoms (for example, ethanolamine, diethanolamine, 2-amino No-2-methylpropanol and triethanolamine) and the like.

In the polyurethane resin (U) in the present invention, a reaction terminator (J) can be used if necessary. As the reaction terminator (J), monoalcohols having 1 to 8 carbon atoms (methanol, ethanol, isopropanol, cellosolves, carbitols, etc.), monoamines having 1 to 10 carbon atoms (monomethylamine, monoethylamine, mono Mono- or dialkylamines such as butylamine, dibutylamine and monooctylamine; mono- or dialkanolamines such as monoethanolamine, diethanolamine and diisopropanolamine).

The polyurethane resin (U) in the present invention can contain additives such as antioxidants, anti-coloring agents, weathering stabilizers, plasticizers, and mold release agents as necessary. The amount of these additives used is preferably 10% by weight or less, more preferably 3% by weight or less, and particularly preferably 1% by weight or less based on the weight of (U).

Equivalent ratio (NCO / OH) of the isocyanate group contained in the aliphatic diisocyanate (B1) and the alicyclic diisocyanate (B2) and the hydroxyl group contained in the polyester diol (A1), polycarbonate diol (A2) and diol (D) ) Is preferably 1.2 to 1.8, more preferably 1.3 to 1.6 from the viewpoint of dispersion stability and particle size control.

Content of the carboxylate anion group based on the weight of (U) in a polyurethane resin (U) is 4-80 mg / g, More preferably, it is 24-50, More preferably, it is 25-40. When the content is less than 4 mg / g, the particles are coarsened and the dispersion stability is lowered, and when the content exceeds 80 mg / g, the water-soluble component is increased and the viscosity is increased.
Here, the weight of the carboxylate anion group does not include the weight of the counter cation.
The method for measuring the content of the carboxylate anion group based on the weight of (U) in the polyurethane resin (U) can be calculated from the acid value measured by the method described in JIS K 0070: 1992 (potentiometric titration method).

Examples of the pigment (P0) used in the present invention include pigment particles containing an inorganic pigment, an organic pigment, and the like. More specifically, a black pigment, a yellow ink pigment, a magenta ink pigment, a cyan ink pigment, and the like can be given. Moreover, there is no restriction | limiting in particular as a shape of a pigment (P), For example, a granular form is mentioned.

Examples of inorganic pigments include carbon black, titanium oxide, zinc white, zinc oxide, tripone, iron oxide, aluminum oxide, silicon dioxide, kaolinite, montmorillonite, talc, barium sulfate, calcium carbonate, silica, alumina, cadmium red, Bengara, molybdenum red, chrome vermilion, molybdate orange, yellow lead, chrome yellow, cadmium yellow, yellow iron oxide, titanium yellow, chromium oxide, pyridian, cobalt green, titanium cobalt green, cobalt chrome green, ultramarine blue, ultramarine blue , Bitumen, cobalt blue, cerulean blue, manganese violet, cobalt violet, mica and the like.

Examples of organic pigments include azo, azomethine, polyazo, phthalocyanine, quinacridone, anthraquinone, indigo, thioindigo, quinophthalone, benzimidazolone, isoindoline, and isoindolinone pigments. Etc.

Examples of black pigments include, for example, carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black, and channel black, and metals such as copper and iron (CI pigment black 11). And metal compounds such as titanium oxide, and organic pigments such as aniline black (CI Pigment Black 1).

Examples of commercially available carbon black include No. 2300, no. 900, MCF-88, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B (all manufactured by Mitsubishi Chemical Corporation); Raven700, 5750, 5250, 5000, 3500, 1255 (all manufactured by Columbia); Regal400R, 330R, 660R, MoguL, Monarch700, 800 880, 900, 1000, 1100, 1300, Monarch 1400 (all manufactured by Cabot Corporation); Color Black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170 , Printex 35, U, V, 140U, 140V, Special Black 6, 5, 4A, 4 (all manufactured by Degussa).

There is no restriction | limiting in particular as a pigment for yellow ink, According to the objective, it can select suitably. Examples thereof include C.I. I. Pigment yellow 1, C.I. I. Pigment yellow 2, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 73, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 75, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 98, C.I. I. Pigment yellow 114, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 174, C.I. I. Pigment yellow 180, C.I. I. And CI Pigment Yellow 185.

There is no restriction | limiting in particular as a pigment for magenta ink, According to the objective, it can select suitably. Examples thereof include C.I. I. Pigment red 5, C.I. I. Pigment red 7, C.I. I. Pigment red 12, C.I. I. Pigment red 48 (Ca), C.I. I. Pigment red 48 (Mn), C.I. I. Pigment red 57 (Ca), C.I. I. Pigment red 57: 1, C.I. I. Pigment red 112, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 146, C.I. I. Pigment red 168, C.I. I. Pigment red 176, C.I. I. Pigment red 184, C.I. I. Pigment red 185, C.I. I. Pigment red 202, pigment violet 19, and the like.

There is no restriction | limiting in particular as a pigment for cyan inks, According to the objective, it can select suitably. Examples thereof include C.I. I. Pigment blue 1, C.I. I. Pigment blue 2, C.I. I. Pigment blue 3, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 15:34, C.I. I. Pigment blue 16, C.I. I. Pigment blue 22, C.I. I. Pigment blue 60, C.I. I. Pigment blue 63, C.I. I. Pigment blue 66; C.I. I. Bat Blue 4, C.I. I. Bat Blue 60 and the like.

In addition, pigments newly produced for the present invention may be used. Moreover, you may use together the pigment mentioned above in the range which does not impair an effect.

Based on the total weight of the polyurethane resin (U) and the pigment (P0), the content of the pigment (P0) is preferably 10 to 40% by weight, more preferably 20 to 30% by weight from the viewpoint of dispersion stability.
The solid content concentration of (R) is preferably 10 to 80% by weight, more preferably 20 to 40% by weight, based on the weight of (R).

The volume average particle diameter of the pigment (P) in the present invention is preferably from 10 to 300 nm, more preferably from 30 to 150 nm, from the viewpoints of dispersion stability and viscosity.
In addition, the measuring method of this volume average particle diameter is measured with the light-scattering particle size distribution measuring apparatus.

In the pigment dispersion, the dried and agglomerated pigment particles are refined and dispersed uniformly and stably in the dispersion medium. The process of dispersing the pigment particles consists of three unit processes of wetting, mechanical disintegration, and stabilization. Of these, the surface modification of the pigment contributes greatly to wetting and stabilization.

There are physical methods and chemical methods for surface modification of pigments. Examples of physical methods include physical adsorption of the dispersant on the pigment surface, and examples of chemical methods include hydrophilic functions such as hydroxyl groups and carboxyl groups by plasma treatment, UV treatment, graft polymerization, and coupling reactions. A method for modifying the group is mentioned.
The physical adsorption of the dispersant tends to increase the viscosity because there is a non-adsorbed dispersant. Moreover, since it is in an equilibrium state of adsorption and desorption, there is a problem that stability is poor.
As for the chemical modification of the hydrophilic group on the pigment surface, self-dispersion can be achieved with carbon black having a large molecular weight. However, since the organic pigment has a small molecular weight, it becomes soluble in water by adding a hydrophilic group and may be dyed.
In order to solve the problem of surface modification of such physical and chemical pigments, there is a resin-coated pigment dispersion in which the pigment is coated with a resin that is insoluble in water and self-dispersible in water.

As a characteristic of the resin-coated pigment, since it is irreversible, there is no change in the dispersion state, and since it is stable against the solvent in the ink vehicle, it is excellent in ejection and storage stability. Further, since the resin itself can have a function as a binder component, there is an advantage that the color development, glossiness and adhesion of the image are excellent.

As a method for producing a resin-coated pigment, all conventionally known methods can be used. As a conventionally known method, a surface polymerization method in which a monomer is adsorbed and polymerized on the surface of a pigment dispersion, a surface deposition in which a pigment is dispersed in a resin solution, a poor solvent for the resin is added, and the resin is deposited on the pigment surface. Method, master-batch by melting and kneading pigment and resin, kneading and refining method to refine by wet process, penetration of pigment solution into pigment aggregate using high-pressure fluid, and expansion energy when released under atmospheric pressure Examples include a method of simultaneously achieving fineness and coating, and a phase inversion emulsification method in which a resin and pigment having self-dispersibility in water are finely divided by wet, and water is added to the organic phase to obtain a resin-coated pigment. .
Among these, the phase inversion emulsification method is most suitable for producing the polyurethane resin-coated pigment aqueous dispersion (R) of the present invention from the viewpoint of volume average particle diameter and stability to an ink vehicle.

<Method for producing polyurethane resin-coated pigment aqueous dispersion (R)>
The polyurethane resin-coated pigment aqueous dispersion (R) of the present invention is produced, for example, by the following steps.
(I) A step of obtaining a polyurethane prepolymer (T).
(Ii) A step in which a solution obtained by dissolving the polyurethane prepolymer (T) in the organic solvent (L) and the pigment (P0) are mixed and refined by mechanical crushing to obtain an organic solvent pigment slurry (S).
(Iii) A step of neutralizing with a neutralizing agent (K).
(Iv) A step of dispersing the obtained neutralized product in water and reacting with the chain extender (H), the reaction terminator (J) and / or water and then removing the organic solvent (L) as necessary.

<Manufacturing process (i)>
The polyurethane prepolymer (T) comprises a polyester diol (A1) and / or a polycarbonate diol (A2), an aliphatic diisocyanate (B1) and / or an alicyclic diisocyanate (B2), and a carboxyl group and / or a carboxylate anion group. It can be obtained by reacting the diol (D) it has with a heatable facility. For example, a method in which (A1) and / or (A2), (B1) and / or (B2), (D) is charged in a container and uniformly stirred, and then heated without stirring in a heating dryer or heating furnace, And a method of reacting by heating with stirring or kneading in a simple pressure reactor (autoclave), Kolben, uniaxial or biaxial kneader, plast mill or universal kneader. Among them, the method of heating and reacting while stirring or kneading increases the homogeneity of the obtained (T), and the mechanical properties, durability, chemical resistance, wear resistance, etc. of the obtained film are more. This is preferable because it tends to be excellent.

The reaction temperature when producing the polyurethane prepolymer (T) is preferably 60 to 120 ° C, more preferably 60 to 110 ° C, from the viewpoint of the contents of the allophanate group and burette group of (T), most preferably Preferably it is 60-100 degreeC. The time for producing (T) can be appropriately selected depending on the equipment used, but generally 1 minute to 100 hours is preferable, more preferably 3 minutes to 30 hours, and particularly preferably. 5 minutes to 20 hours. If it is this range, (T) which can fully exhibit the effect of the present invention will be obtained.

The polyurethane prepolymer (T) can be diluted with an organic solvent (L). Examples of the organic solvent (L) include ketone solvents (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), ester solvents (ethyl acetate, butyl acetate, γ-butyrolactone, etc.), ether solvents (THF, etc.), amide solvents [ N, N-dimethylformamide (hereinafter abbreviated as DMF), N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, etc.], alcohol solvents (methanol, ethanol, isopropyl alcohol, etc.) and aroma Group hydrocarbon solvents (toluene, xylene, etc.). These organic solvents may be used individually by 1 type, and may use 2 or more types together. Of these, amide solvents are preferred from the viewpoint of solubility of the polyurethane prepolymer (T).

The organic solvent (L) may be added before the urethanization reaction, during the urethanization reaction, after the urethanization reaction, or before emulsification, but is used before the urethanization reaction from the viewpoint of the uniformity of the reaction system. Is preferred.

In order to control the urethanization reaction rate, known reaction catalysts (such as tin octylate and bismuth octylate) and reaction retarders (such as phosphoric acid) can be used. The addition amount of these catalysts or reaction retarders 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 (T). %.

<Manufacturing process (ii)>
As an apparatus for mixing the polyurethane prepolymer (T) and the pigment (P0), the apparatus used for the synthesis of (T) can be used as it is.
Examples of the disperser used when the pigment (P0) is refined by mechanical crushing include a paint shaker, a ball mill, a sand mill, and a nano mill. Specifically, they are SC mill (made by Nippon Coke Industries), TSU-6U (made by IMEX), etc.

<Manufacturing process (iii)>
If necessary, the carboxyl group portion introduced into the polyurethane prepolymer (T) is neutralized with a neutralizing agent (K). The neutralizing agent (K) may be added at any time before the urethanization reaction, during the urethanization reaction, after the urethanization reaction, before emulsification, during emulsification, or after dispersion of the emulsified aqueous medium. From the viewpoint of the properties and stability of the composite particle dispersion for ink, it is preferably added before or during emulsification.

The neutralizing agent used in (K) may be added at any time before the urethanization reaction, during the urethanization reaction, after the urethanization reaction, before the water dispersion step, during the water dispersion step or after the water dispersion. From the viewpoint of the stability of the urethane resin and the stability of the aqueous dispersion, it is preferably added before or during the water dispersion step. Further, the neutralizing agent volatilized at the time of solvent removal may be added after the solvent removal, and the type of neutralizing agent to be added can be freely selected from those described above.

The amount of (K) used is adjusted so that the carboxylate anion group content based on the weight of the polyurethane resin (U) is 23 to 80 mg / g from the viewpoint of the stability of the polyurethane resin-coated pigment aqueous dispersion. The neutralization rate of the carboxyl group in the neutralization step is preferably 20 to 100%, more preferably 60 to 100% from the viewpoint of dispersion stability.

<Manufacturing process (iv)>
As a method for emulsifying the neutralized product obtained in step (iii), for example, in the presence of an organic solvent (L), a dispersant (e), a chain extender (H), and a reaction terminator (J) as necessary. Disperse in an aqueous medium and carry out the reaction [water, chain extension with (H), and if necessary, stop with (J)] until the isocyanate group is substantially eliminated, and distill off the organic solvent (L) if necessary. The method of doing is mentioned.

The aqueous medium in the present invention means water and a mixture of water and the organic solvent (L). The organic solvent used in the aqueous medium is preferably a water-soluble organic solvent from the viewpoint of dispersibility. When the organic solvent (L) is used, it may be distilled off if necessary during and / or after the production of the aqueous polyurethane resin-coated pigment dispersion.

Examples of the dispersant (e) include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants and other emulsifying dispersants. (E) may be used alone or in combination of two or more.

There is no particular limitation on the system of the apparatus for adding water and dispersing the polyurethane resin-coated pigment (P) while stirring the slurry (S). For example, (1) vertical stirring system, (2) rotor-fixed Child type [for example, homomixer (manufactured by ASONE)], (3) Line mill type [for example, line flow mixer], (4) Static tube mixing type [for example, static mixer], (5) Vibration type [for example, “VIBRO MIXER” ( Chilling Kogyo Co., Ltd.)], (6) Ultrasonic impact type [for example, ultrasonic homogenizer], (7) High pressure impact type [for example, Gaurin homogenizer (manufactured by Gaurin)], (8) ] And (9) Centrifugal thin film contact type [e.g., "Fillmix" (manufactured by Primemix)] and the like. Of these, (2) is preferable.

Hereinafter, the preparation of the water-based ink (X) using the aqueous polyurethane resin-coated pigment dispersion (R) of the present invention will be described.

The water-based ink (X) can contain other components appropriately selected as necessary. For example, 1 type (s) or 2 or more types can be contained in a crosslinking agent, a viscosity modifier, an antifoamer, antiseptic | preservative, a degradation inhibitor, a stabilizer, antifreezing agent, water, etc.

Examples of crosslinking agents include water-soluble or aqueous medium-dispersible amino resins, water-soluble or aqueous medium-dispersible polyepoxides, water-soluble or aqueous medium-dispersed blocked polyisocyanate compounds, polyethylene urea, water-soluble or aqueous medium-dispersible compounds. Examples thereof include polycarbodiimide resins, water-soluble or aqueous medium-dispersible polyoxazoline resins, and the like. The amount of the crosslinking agent used is preferably such that the number of moles of the reactive group possessed by the crosslinking agent with respect to the number of moles of the reactive group possessed by the polyurethane resin (A) is 0.05 to 2.0 times. The amount is 0.1 to 1.0 times.

Viscosity modifiers include thickeners such as inorganic viscosity modifiers (such as sodium silicate and bentonite), cellulose viscosity modifiers (such as methylcellulose, carboxymethylcellulose, and hydroxymethylcellulose with Mn of 20,000 or more), proteins System viscosity modifiers (casein, casein soda, casein ammonium, etc.), acrylics (sodium polyacrylate and ammonium polyacrylate with Mn of 20,000 or more) and vinyl viscosity modifiers (Mn of 20,000 or more) Polyvinyl alcohol).
Examples of antifoaming agents include long-chain alcohols (such as octyl alcohol), sorbitan derivatives (such as sorbitan monooleate), and silicone oils (such as polymethylsiloxane and polyether-modified silicone).

Examples of the preservative include organic nitrogen sulfur compound preservatives and organic sulfur halide preservatives.
Deterioration inhibitors and stabilizers (such as UV absorbers and antioxidants) include hindered phenol-based, hindered amine-based, hydrazine-based, phosphorus-based, benzophenone-based and benzotriazole-based deterioration inhibitors and stabilizers. .
Examples of the antifreezing agent include ethylene glycol and propylene glycol.
The content of the viscosity modifier, antifoaming agent, antiseptic, deterioration preventing agent, stabilizer and antifreezing agent is usually preferably 5% by weight or less, more preferably 3% by weight or less, respectively, based on the weight of the aqueous paint. It is.

A solvent may be further added to the water-based ink (X) for the purpose of improving the appearance of the coated film after drying, or for the purpose of delaying drying in order to prevent clogging in the coating or printing line. Examples of the solvent to be added include monohydric alcohols having 1 to 20 carbon atoms (such as methanol, ethanol and propanol), glycols having 1 to 20 carbon atoms (such as ethylene glycol, propylene glycol and diethylene glycol), and 3 having 1 to 20 carbon atoms. Alcohols having higher valences (such as glycerin) and cellosolves having 1 to 20 carbon atoms (such as methyl and ethyl cellosolve) can be used. The content of the solvent to be added is preferably 80% by weight or less, more preferably 70% by weight or less, based on the weight of the aqueous paint or ink.

The water-based ink (X) using the polyurethane resin-coated pigment aqueous dispersion (R) of the present invention is produced by mixing and stirring the (R) of the present invention and the components described above. When mixing, all the components may be mixed at the same time, or each component may be added stepwise and mixed.
The solid content concentration of the water-based ink (X) is preferably 3 to 70% by weight, more preferably 7 to 60% by weight.

The polyurethane resin-coated pigment aqueous dispersion (R) of the present invention can be used for applications such as offset printing ink, relief printing ink, gravure printing ink, silk printing ink, inkjet recording ink, and color filter. I can do it.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these. Hereinafter, the part means part by weight.

Example 1 <Production of Pigment Water Dispersion (R-1)>
As a polyester diol (A-1), 57.8 parts Sanester 4620 (manufactured by Sanyo Chemical Industries), 10.5 parts hexamethylene diisocyanate (B1-1), 2 , 2-dimethylolpropionic acid (D-1) 1.7 parts and 30 parts of methyl ethyl ketone were added and stirred at 85 ° C. for 10 hours to carry out a urethanation reaction. A methyl ethyl ketone solution of polyurethane prepolymer (T-1) (V -1) was produced.
Next, 17.5 parts of carbon black MA230 (P-1) was added as a pigment (P), and 117.5 parts of glass beads (ASGB-320, manufactured by ASONE) were added, followed by a pigment disperser (TSU-6U, Imex). For 4 hours to obtain an organic solvent pigment slurry (S-1).
After adding and homogenizing 1.0 part of triethylamine as a neutralizing agent (K) to 235 parts of the organic solvent pigment slurry (S-1), 38 parts of water was added with stirring at 200 rpm to disperse the mixture. To the obtained dispersion, 5.2 parts of a 10% by weight diethylenetriamine aqueous solution as a chain extender (H) was added, methyl ethyl ketone was distilled off at 65 ° C. for 8 hours under reduced pressure, glass beads were removed by filtration, and polyurethane was removed. A pigment aqueous dispersion (R-1) coated with resin (U) was obtained.

Example 2 <Production of pigment aqueous dispersion (R-2)>
In a simple pressure reactor equipped with a stirrer and a heating device, 15.3 parts of polyester diol (A-1) hexamethylene diisocyanate (B1-1), 2,2-dimethylolpropionic acid (D-1) 4.8 And 30 parts of methyl ethyl ketone were added and stirred at 85 ° C. for 10 hours to carry out a urethanation reaction to produce a methyl ethyl ketone solution (V-2) of a polyurethane prepolymer. Next, 17.5 parts of carbon black MA230 (P-1) was added, 117.5 parts of glass beads were added, and then crushed with a pigment disperser for 4 hours to obtain an organic solvent pigment slurry (S-2). Obtained.
After adding 3.6 parts of triethylamine to 235 parts of the organic solvent pigment slurry (S-2) and homogenizing, 388 parts of water was added with stirring at 200 rpm to disperse the mixture. 8.5 parts of diethylenetriamine aqueous solution was added to the obtained dispersion, methyl ethyl ketone was distilled off at 65 ° C. for 8 hours under reduced pressure, the glass beads were removed by filtration, and the pigment aqueous dispersion coated with polyurethane resin (U) (R-2) was obtained.

Example 3 <Production of Pigment Water Dispersion (R-3)>
Kuraray polyol P-2020 (manufactured by Kuraray) (A1-2) 16.2 parts, hexamethylene diisocyanate (B1-1) 22.6 parts, 4,4 ′ in a simple pressure reactor equipped with a stirrer and a heating device -14.5 parts of dicyclohexylmethane diisocyanate (B2-1), 16.7 parts of 2,2-dimethylolpropionic acid (D-1) and 30 parts of methyl ethyl ketone were added and stirred at 85 ° C for 10 hours to carry out a urethanization reaction. And a methyl ethyl ketone solution (V-3) of polyurethane prepolymer was produced. Next, 17.5 parts of carbon black MA230 (P-1) was added, 117.5 parts of glass beads were added, and then pulverized for 4 hours with a pigment disperser to obtain an organic solvent pigment slurry (S-3). Obtained.
After adding 12.6 parts of triethylamine to 235 parts of the organic solvent-based pigment slurry (S-3) and homogenizing, 388 parts of water was added with stirring at 200 rpm to disperse the mixture. 11.5 parts of diethylenetriamine aqueous solution was added to the obtained dispersion, methyl ethyl ketone was distilled off at 65 ° C. for 8 hours under reduced pressure, the glass beads were removed by filtration, and the pigment aqueous dispersion coated with polyurethane resin (U) (R-3) was obtained.

Example 4 <Production of pigment aqueous dispersion (R-4)>
In a simple pressure reactor equipped with a stirrer and a heating device, 20.4 parts of Etanacol UH-200 (manufactured by Ube Industries) (A2-1), 39.2 parts of 4,4′-dicyclohexylmethane diisocyanate (B2-1) , 2,2-dimethylolpropionic acid (D-1) 10.4 parts and methyl ethyl ketone 30 parts were stirred at 85 ° C. for 10 hours to carry out a urethanation reaction, and a methyl ethyl ketone solution of polyurethane prepolymer (V-4) Manufactured. Next, 35.0 parts of Pigment Blue 15: 3 (P-2) and 117.5 parts of glass beads were added, and then crushed with a pigment disperser for 4 hours to obtain an organic solvent pigment slurry (S-4). )
After 7.9 parts of triethylamine was added to 270 parts of the organic solvent-based pigment slurry (S-4) and homogenized, 388 parts of water was added with stirring at 200 rpm to disperse the mixture. 19.3 parts of diethylenetriamine aqueous solution was added to the resulting dispersion, methyl ethyl ketone was distilled off at 65 ° C. for 8 hours under reduced pressure, the glass beads were removed by filtration, and the pigment aqueous dispersion coated with polyurethane resin (U) (R-4) was obtained.

Example 5 <Production of pigment aqueous dispersion (R-5)>
In a simple pressure reactor equipped with a stirrer and a heating device, 21.6 parts of Kuraray polyol P-2020 (A1-2), 21.6 parts of etanacol UH-200 (A2-1), hexamethylene diisocyanate (B1-1) ) 20.5 parts, 2,2-dimethylolpropionic acid (D-1) 6.3 parts and methyl ethyl ketone 30 parts, and stirred at 85 ° C. for 10 hours to carry out a urethanation reaction, a polyurethane prepolymer methyl ethyl ketone solution (V-5) was produced. Next, 17.5 parts of Pigment Blue 15: 3 (P-2) was added, 117.5 parts of glass beads (ASGB-320 made by ASONE) were added, and the mixture was crushed with a pigment disperser for 4 hours. A pigment slurry (S-5) was obtained.
After 4.7 parts of triethylamine was added to 235 parts of the organic solvent-based pigment slurry (S-5) and homogenized, 388 parts of water was added with stirring at 200 rpm to disperse the mixture. 16.8 parts of diethylenetriamine aqueous solution was added to the obtained dispersion, methyl ethyl ketone was distilled off at 65 ° C. under reduced pressure for 8 hours, the glass beads were removed by filtration, and the pigment aqueous dispersion coated with polyurethane resin (U) (R-5) was obtained.

Example 6 <Production of Pigment Water Dispersion (R-6)>
PTMG2000 [poly (oxytetramethylene) glycol with Mn = 2,000, manufactured by Mitsubishi Chemical Corporation] (A3-1), 46.1 parts, hexamethylene diisocyanate in a simple pressure reactor equipped with a stirrer and a heating device (B1-1) 17.6 parts, 2,2-dimethylolpropionic acid (D-1) 6.3 parts and methyl ethyl ketone 30 parts were charged and stirred at 85 ° C. for 10 hours to carry out urethanation reaction. A methyl ethyl ketone solution (V-6) of the polymer was produced. Next, 35.0 parts of carbon black MA230 (P-1) was added and 135 parts of glass beads were added, followed by crushing for 4 hours with a pigment disperser to obtain an organic solvent pigment slurry (S-6). .
After 4.7 parts of triethylamine was added to 270 parts of the organic solvent pigment slurry (S-6) and homogenized, 388 parts of water was added with stirring at 200 rpm to disperse the mixture. 10.1 parts of diethylenetriamine aqueous solution was added to the obtained dispersion, methyl ethyl ketone was distilled off at 65 ° C. for 8 hours under reduced pressure, the glass beads were removed by filtration, and the pigment aqueous dispersion coated with polyurethane resin (U) (R-6) was obtained.

Comparative Example 1 <Production of Pigment Water Dispersion (R′-1)>
In a simple pressure reactor equipped with a stirrer and a heating device, 61.6 parts Sanester 4620 (A1-1), 8.2 parts hexamethylene diisocyanate (B1-1), 2,2-dimethylolpropionic acid (D -1) 0.2 part and 30 parts of methyl ethyl ketone were added and stirred at 85 ° C. for 10 hours to carry out a urethanation reaction to produce a methyl ethyl ketone solution (V′-1) of a polyurethane prepolymer. Next, 17.5 parts of carbon black MA230 (P-1) was added, 117.5 parts of glass beads were added, and then pulverized with a pigment disperser for 4 hours to obtain an organic solvent pigment slurry (S′-1). Got.
After adding 0.1 part of triethylamine to 235 parts of the organic solvent pigment slurry (S′-1) and homogenizing, 388 parts of water was added with stirring at 200 rpm to disperse the mixture. 3.6 parts of diethylenetriamine aqueous solution was added to the obtained dispersion, methyl ethyl ketone was distilled off at 65 ° C. for 8 hours under reduced pressure, the glass beads were removed by filtration, and the pigment aqueous dispersion coated with polyurethane resin (U) (R′-1) was obtained.

Comparative Example 2 <Production of Pigment Water Dispersion (R′-2)>
24.3 parts of Kuraray polyol P-2020 (A1-2), 28.4 parts of hexamethylene diisocyanate (B1-1), 2,2-dimethylolpropionic acid in a simple pressure reactor equipped with a stirrer and a heating device (D-1) 17.3 parts and 30 parts of methyl ethyl ketone were added and stirred at 85 ° C. for 10 hours to carry out a urethanation reaction to produce a methyl ethyl ketone solution (V′-2) of a polyurethane prepolymer. Next, 17.5 parts of Pigment Blue 15: 3 (P-2) was added, 117.5 parts of glass beads were added, and the mixture was crushed with a pigment disperser for 4 hours to obtain an organic solvent-based pigment slurry (S′- 2) was obtained.
After adding 13.1 parts of triethylamine to 235 parts of the organic solvent pigment slurry (S′-2) and homogenizing, 382 parts of water was added with stirring at 200 rpm to disperse the mixture. 6.9 parts of diethylenetriamine aqueous solution was added to the resulting dispersion, methyl ethyl ketone was distilled off at 65 ° C. for 8 hours under reduced pressure, the glass beads were removed by filtration, and the pigment aqueous dispersion coated with polyurethane resin (U) (R′-2) was obtained.

Comparative Example 3 <Production of Pigment Water Dispersion (R′-3)>
In a simple pressure reactor equipped with a stirrer and a heating device, 33.8 parts Sanester 4620 (A1-1), 27.8 parts diphenylmethane diisocyanate (B′-1) of aromatic diisocyanate, 2,2-dimethylol Propionic acid (D-1) (8.4 parts) and methyl ethyl ketone (30 parts) were added and stirred at 85 ° C. for 10 hours to carry out urethanation reaction to produce a polyurethane prepolymer methyl ethyl ketone solution (V′-3). Next, 17.5 parts of carbon black MA230 (P-1) was added, 117.5 parts of glass beads were added, and then the mixture was crushed with a pigment disperser for 4 hours to obtain an organic solvent pigment slurry (S′-3). Obtained.
After 6.3 parts of triethylamine was added to 235 parts of the organic solvent pigment slurry (S′-3) and homogenized, 385 parts of water was added with stirring at 200 rpm to disperse the mixture. 9.0 parts of diethylenetriamine aqueous solution was added to the obtained dispersion, methyl ethyl ketone was distilled off at 65 ° C. for 8 hours under reduced pressure, the glass beads were removed by filtration, and the pigment aqueous dispersion coated with polyurethane resin (U) (R′-3) was obtained.

Comparative Example 4 <Production of pigment aqueous dispersion (W-1)>
In a simple pressure reactor equipped with a stirrer and a heating device, 46.1 parts of Sun Ester 4620 (A1-1), 17.6 parts of hexamethylene diisocyanate (B1-1), 2,2-dimethylolpropionic acid (D -1) 6.3 parts and 30 parts of methyl ethyl ketone were charged and stirred at 85 ° C. for 10 hours to carry out a urethanization reaction to obtain a methyl ethyl ketone solution (V′-4) of a polyurethane prepolymer.
After 3.6 parts of triethylamine was added to 82.5 parts of the obtained (V′-4) and homogenized, 318 parts of water was added with stirring at 200 rpm to disperse the polyurethane resin. 8.5 parts of diethylenetriamine aqueous solution was added to the obtained polyurethane resin aqueous dispersion, and methyl ethyl ketone was distilled off at 65 ° C. for 8 hours under reduced pressure to obtain an aqueous polyurethane resin dispersion.
Furthermore, 87.5 parts of pigment water dispersion [“Aqua-Black 162”, manufactured by Tokai Carbon Co., Ltd., solid content 20 wt%] was added, and a blend of polyurethane resin water dispersion and pigment water dispersion (W-1) was added. Obtained.

Table 1 shows the contents of (R-1) to (R-6), (R'-1) to (R'-3), and (W-1).

<Examples 7 to 12 and Comparative Examples 6 to 8>
As described in Table 2, the polyurethane resin-coated water dispersions (R-1) to (R-6) and (R′-1) to (R) obtained in Examples 1 to 6 and Comparative Examples 1 to 3 '-3) 100 parts, 25 parts of propylene glycol, 25 parts of glycerin, and 20 parts of ion-exchanged water were mixed and mixed for 10 minutes to obtain inks (X-1) to (X-6), (X'-1 ) To (X′-3) were obtained.

<Comparative Example 9>
Compound (W-1) 100 parts of the polyurethane resin water dispersion obtained in Comparative Example 5 and the pigment water dispersion, 25 parts of propylene glycol, 25 parts of glycerin, and 20 ion-exchanged water were mixed for 10 minutes. As a result, an ink (X′-4) was obtained.

The evaluation results using the obtained water-based ink are shown in Table 2. In addition, the evaluation method in this invention is as follows.
<Volume average particle diameter>
The water-based ink was diluted with ion-exchanged water so that the solid content of the pigment was 0.01% by weight, and then measured using a light scattering particle size distribution analyzer (Nanoparticle analyzer SZ-100 manufactured by Horiba, Ltd.).

<Viscosity of water-based ink>
The viscosity of the water-based ink was measured at a rotation speed of 20 rpm using a TVE-25 viscometer viscometer manufactured by Toki Sangyo Co., Ltd.

<Storage stability of water-based ink>
The aqueous ink was put in a screw tube and stored at 70 ° C. for 1 week, and the storage stability with respect to the state of thickening and aggregation was evaluated by the rate of change in viscosity before and after storage.
Viscosity change rate (%) = [viscosity after 1 week−initial viscosity] × 100 / initial viscosity

<Method for evaluating adhesion to coated paper>
A water-based ink was applied to 5 cm × 20 cm coated paper (“Aurora Coat”, manufactured by Nippon Paper Industries Co., Ltd.) so that the film thickness after drying was 2 μm, and dried at 140 ° C. for 10 minutes to prepare a coating film. A peel test was performed on the surface of the coating film with cello tape (registered trademark), and the number of 1 mm square coating films remaining was examined.
◎: Residual amount 90% or more ○: Residual amount 80% or more and less than 90% △: Residual amount 60% or more and less than 80% ×: Residual amount 60% or less

<Method for evaluating adhesion to PET film>
A surface-coated polyester film (“Espet E-5102”, manufactured by Toyobo Co., Ltd.) was coated with water-based ink to a thickness of 2 μm in solid content and dried at 60 ° C. for 1 minute. A peel test was performed with (registered trademark), and the number of 1 mm square coating films remaining was examined.
◎: Residual amount 90% or more ○: Residual amount 80% or more and less than 90% △: Residual amount 60% or more and less than 80% ×: Residual amount 60% or less

<Method for evaluating adhesion to fabric>
A water-based ink is applied to a cotton broad cloth so that the coating amount is 1 mg / cm ² , dried for 5 minutes with a circulating dryer at 160 ° C., and the resulting fabric is used to define the JIS L0849 (Type II). The wet test was conducted in accordance with the above method, and the contamination of the white cotton fabric for friction was evaluated based on the contamination gray scale.
○: Friction fastness Wet friction class 4 △: Friction fastness Wet friction class 3 ×: Friction fastness Wet friction class 2

As shown in Table 2, it is apparent that the aqueous inks containing the aqueous polyurethane resin-coated pigment dispersions of Examples 7 to 12 of the present invention have excellent storage stability.
Moreover, the water-based ink containing the polyurethane resin-coated pigment aqueous dispersions of Examples 7 to 12 exhibits excellent adhesiveness of 80% or more with respect to any of the base materials of coated paper, PET film, and fabric. On the other hand, Comparative Examples 6 to 9 had an adhesiveness of less than 80% for any of the substrates.

The polyurethane resin-coated pigment aqueous dispersion of the present invention comprises an inkjet ink, an aqueous coating composition, an aqueous adhesive composition, an aqueous fiber processing agent composition (a binder composition for pigment printing, a binder composition for nonwoven fabric, and a reinforcing fiber). Sizing agent composition, binder composition for antibacterial agent and raw material composition for artificial leather / synthetic leather, etc.), aqueous coating composition (waterproof coating composition, water repellent coating composition, antifouling coating composition, etc.), aqueous paper It can be suitably used for a treating agent composition, a water-based ink composition, and the like.

Claims (6)

  The pigment (P0) is an aqueous dispersion of the pigment (P) coated with the polyurethane resin (U), and the polyurethane resin (U) is a polyester diol (A1), a polycarbonate diol (A2), and a polyether diol ( One or more polyols (A) selected from the group consisting of A3), aliphatic diisocyanates (B1) and / or alicyclic diisocyanates (B2), and diols having carboxyl groups and / or carboxylate anion groups (D) Is an essential constituent monomer, and the polyurethane resin-coated pigment aqueous dispersion (R) has a total content of carboxyl groups and carboxylate anion groups of 4 to 80 mg / g based on the weight of the polyurethane resin (U).   Equivalent ratio (NCO / OH) of isocyanate group contained in aliphatic diisocyanate (B1) and alicyclic diisocyanate (B2) and hydroxyl group contained in polyester diol (A1), polycarbonate diol (A2) and diol (D) The pigment aqueous dispersion according to claim 1, wherein is from 1.2 to 1.8.   The pigment aqueous dispersion according to claim 1 or 2, wherein the volume average particle diameter of the pigment (P) by light scattering measurement is 10 to 300 nm. The pigment water dispersion according to any one of claims 1 to 3, wherein the content of the pigment (P0) is 10 to 40% by weight based on the total weight of the polyurethane resin (U) and the pigment (P0).   The pigment water dispersion according to any one of claims 1 to 4, wherein the polyol (A) contains a polyol having an aromatic ring in the molecule.   A water-based ink (X) comprising the polyurethane resin-coated pigment aqueous dispersion (R) according to any one of claims 1 to 5.