JP2017125183A - Composite particle for ink, ink composition and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite particle for ink capable of making a pigment ink low viscosity, capable of increasing binder resin concentration and pigment concentration therefor and excellent in scratch resistance and image concentration of images, excellent in adhesiveness between a coating layer and pigment particles without falling of the coating layer and excellent in dispersion stability, and an ink composition using the particles.SOLUTION: There is provided a composite particle for ink (C) containing an urethane resin (A) and pigment particles (B), in which a surface of the pigment particles (B) is coated with a coating layer (L) containing the urethane resin (A), having an impregnation layer (M), in which a polymer (F) having a group (j) having reactivity with an isocyanate group is impregnated, inside from the surface of the pigment particles (B), in which the polymer (F) and the urethane resin (A) are bound by a covalent bond, average thickness of the impregnation layer (M) is 0.1% to 50% of volume average particle diameter of the composite particles.SELECTED DRAWING: Figure 1

Description

  The present invention relates to composite particles for ink, an ink composition, and a method for producing the same.

In recent years, pigments are often selected as dyes for inks rather than dyes from the viewpoint of light resistance. In addition, since the use of pigments as colorants is advantageous in that printing can be performed on various printing media as compared with dyes, recently, printing techniques using pigments have been actively studied. In general, ink-jet inks using pigments are required to have image scratch resistance and high image quality. On the other hand, inkjet inks are required to have low viscosity because they do not clog the nozzles, but this conflicts with scratch resistance and high image density. Scratch resistance and image density are improved by increasing the binder resin concentration and the pigment concentration in the ink, respectively, but the viscosity of the ink is increased, and there is a drawback that the ink dischargeability is impaired.
A polymer-coated pigment has been proposed aiming at an image having excellent scratch resistance (Patent Documents 1, 2, and 3). However, the surface modification method by surface adsorption or surface reaction has structural changes due to adsorption / desorption equilibrium and reaction, and there are problems that lead to performance deterioration such as foaming, color change, and thickening.
Moreover, in order to achieve high image quality, it is necessary to stably disperse the pigment, and a method using a polymer dispersant has been proposed (Patent Document 4). However, in the proposed method, the dispersion of the dispersant from the pigment surface occurs with time, so that the dispersion stability is insufficient, and there is a problem that the removed dispersant lowers the surface tension of the ink.

JP 2004-189929 A Japanese Patent Laying-Open No. 2015-25122 JP 2015-145508 A JP 2010-222405 A

  The object of the present invention is to solve the above-mentioned problems of the prior art. That is, the present invention can reduce the viscosity of the pigment ink, so that the binder resin concentration / pigment concentration can be increased, the image has excellent scratch resistance and image density, and the coating layer and pigment particles have excellent adhesion. An object of the present invention is to provide composite particles for ink that do not drop off and have excellent dispersion stability, and an ink composition using the particles.

As a result of intensive studies to achieve the above object, the present inventors have found the following. The present invention is a composite particle comprising a urethane resin (A) and pigment particles (B), the surface of the pigment particles (B) is coated with a coating layer (L) containing the urethane resin (A), The pigment particle (B) has an impregnated layer (M) impregnated with a polymer (F) having a group (j) having reactivity with an isocyanate group from the surface to the inside, and the polymer (F) Ink composite particles (C) in which the urethane resin (A) is bonded by a covalent bond, and the average thickness of the impregnated layer (M) is 0.1% to 50% of the volume average particle size of the composite particles;
Pigment particles (B), liquid, subcritical or supercritical carbon dioxide (E), a monomer (f) having a group (j) having reactivity with an isocyanate group, and a solvent (S) By mixing, impregnating the monomer particles (f) into the pigment particles (B) and performing a polymerization reaction, the composite particles in which the pigment particles (B) are coated with the polymer (F) having the group (j) ( After forming C0), carbon dioxide (E) in a liquid, subcritical or supercritical state is removed to obtain dispersion (G) in which composite particles (C0) are dispersed in solvent (S). And
Subsequently, after making this dispersion liquid (G) and the prepolymer (P) which has an isocyanate group react, it neutralizes with a neutralizing agent (D), the obtained neutralized material is emulsified in water, and a chain | strand is obtained. Including a step of removing the solvent (S) after the chain extension reaction with the extender (H).
Production method of aqueous dispersion (Q) of composite particle for ink containing composite particle for ink (C) which is pigment particle coated with urethane resin; pigment particle (B) and liquid, subcritical or supercritical state A monomer (f) having carbon dioxide (E), a group (j) having reactivity with an isocyanate group, and a solvent (S) are mixed, and the monomer (f) is mixed with pigment particles (B). Next, carbon dioxide (E) in a liquid, subcritical or supercritical state is removed, followed by polymerization reaction, whereby the pigment particles (B) have a group (j) in the solvent (S). Obtaining a dispersion (G) in which the composite particles (C0) coated with the coalescence (F) are dispersed,
Subsequently, after making this dispersion liquid (G) and the prepolymer (P) which has an isocyanate group react, it neutralizes with a neutralizing agent (D), the obtained neutralized material is emulsified in water, and a chain | strand is obtained. Including a step of removing the solvent (S) after the chain extension reaction with the extender (H).
It is a manufacturing method of the composite particle | grain aqueous dispersion (Q) for ink containing the composite particle for ink (C) which is a pigment particle coat | covered with the urethane resin.

  According to the present invention, the viscosity of the pigment ink can be reduced, so that the binder resin concentration / pigment concentration can be increased, the image has excellent scratch resistance / image density, excellent adhesion between the coating layer and the pigment particles, and the coating layer can be removed. Ink composite particles excellent in dispersion stability, an ink composition containing the particles, and an aqueous ink containing the composition can be provided.

Manufacturing apparatus for composite particles (C0) for ink

B1: Carbon dioxide cylinder T1: Dissolution tank P1: Solution pump P2: Carbon dioxide pump M1: Static mixer V1: Valve T2: Pressure-resistant receiving tank

The present invention is described in detail below.
<Composite particles for ink (C)>
The composite particle for ink (C) is a composite particle containing a urethane resin (A) and a pigment particle (B), and the surface of the pigment particle (B) contains the urethane resin (A) (L ) And an impregnated layer (M) impregnated with a polymer (F) having a group (j) having reactivity with an isocyanate group from the surface to the inside of the pigment particle (B). The coalesced (F) and the urethane resin (A) are bonded by a covalent bond, and the average thickness of the impregnated layer (M) is 0.1% to 50% of the volume average particle diameter of the composite particles. .
Between the coating layer (L) and the impregnation layer (M), it is composed of a polymer (F) having a group (j) having reactivity with an isocyanate group, and covers the surface of the pigment particles (B). A covering layer (M1) is present. The pigment particle (B) is a pigment particle having the impregnation layer (M) and the coating layer (M1). It is difficult to distinguish the coating layer (M1) and the coating layer (L) in measurement. At least a part of the polymer (F) contained in the impregnation layer (M) and the coating layer (M1) is a covalent bond such as a urethane bond or a urea bond with the urethane resin (A) contained in the coating layer (L). Are combined.

From the viewpoint of adhesion of the coating film, the surface of the pigment particles (B) is coated with a coating layer (L) containing the polymer (F), and the polymer ( F) has an impregnated layer (M) impregnated. The average thickness of the impregnated layer (M) is 0.1 to 50% of the volume average particle diameter of the composite particles (C0). From the viewpoint of dispersion stability, the lower limit is preferably 0.6% or more of the volume average particle diameter (D50) of the composite particles (C0), more preferably 2.0% or more, and particularly preferably 3.0%. If the pigment is a pigment, the upper limit is preferably 45% or less, more preferably 30% or less of the volume average particle diameter (D50) of the composite particles (C0) from the viewpoint of the physical properties of the solid particles such as color developability. Especially preferably, it is 20% or less. The average thickness of the impregnated layer is the thickness of the impregnated layer impregnated with the polymer (F) from the surface of the pigment particle (B) to the inside, and the average length of the impregnated layer from the surface of the pigment particle (B) is averaged. It is the value. The thickness of the impregnated layer is a value obtained by photographing the composite particle (C0) using a scanning transmission electron microscope and analyzing the image. The average thickness of the impregnated layer can be adjusted by adjusting the pressure and treatment time for impregnation of the polymer (F) into the pigment with a penetrating solvent or liquid, subcritical or supercritical carbon dioxide. When the average thickness of the impregnated layer (M) is less than 0.1% of the volume average particle diameter of the composite particles (C0), a drop-off component is likely to occur and ink characteristics are impaired. Further, particles having an average thickness of the impregnated layer (M) exceeding 50% of the volume average particle diameter of the composite particles (C0) cannot be obtained.

The volume average particle diameter (D50) of the composite particles (C0) is preferably 10 nm or more and less than 800 nm from the viewpoint of the coloring power of the pigment. More preferably, it is 15 nm or more and less than 450 nm. Particularly preferably, it is 20 nm or more and less than 400 nm.
The volume average particle diameter (D50) of the composite particles (C0) is a value measured by a dynamic light scattering method using a particle size measuring apparatus LB-550 manufactured by Horiba, Ltd. in an environment of 23 ° C. and 55% RH.

The concentration of the group (j) having reactivity with an isocyanate group in the composite particle (C0) is preferably 0.01 mmol / g or more and 1.0 mmol / g or less, more preferably based on the weight of the pigment particle (B). It is 0.01 mmol / g or more and 0.5 mmol / g or less, and most preferably 0.01 or more and 0.3 mmol / g or less.

<Urethane resin (A)>
The urethane resin (A) in the present invention comprises the polyol (a), the polyisocyanate (b) and the compound (c) containing a hydrophilic group and an active hydrogen atom as essential constituent monomers, and if necessary, a chain extender ( It is a resin comprising H) and a reaction terminator (d) as constituent monomers.
Each component will be described below.

Examples of the polyol (a) include a polymer polyol (a1) having a number average molecular weight (hereinafter abbreviated as Mn) of 300 or more and a low molecular polyol (a2) having a Mn of less than 300.
In the present invention, the Mn of the polyol is measured by gel permeation chromatography (GPC) using polyethylene glycol as a standard. However, Mn of the low molecular polyol is a calculated value from the chemical formula.

  Examples of the polymer polyol (a1) having Mn of 300 or more include polyether polyol (a11) and polyester polyol (a12).

  Examples of the polyether polyol (a11) include aliphatic polyether polyols and aromatic ring-containing polyether polyols.

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

  Commercially available products of aliphatic polyether polyols 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 aromatic polyether polyols include ethylene oxide (hereinafter abbreviated as EO) adducts of bisphenol A [EO 2 mol adduct of bisphenol A, EO 4 mol adduct of bisphenol A, EO 6 mol adduct of bisphenol A, and bisphenol A. EO 8 mol adduct, bisphenol A EO 10 mol adduct and bisphenol A EO 20 mol adduct, etc.] and bisphenol A propylene oxide (hereinafter abbreviated as PO) adduct [bisphenol A PO 2 mol adduct, bisphenol A PO3 molar adducts, PO5 molar adducts of bisphenol A, etc.], and EO or PO adducts of resorcin, and the like.

  Mn of (a11) is preferably 300 or more, more preferably 300 to 10,000, and still more preferably 300 to 6,000, from the viewpoint of mechanical properties of the urethane resin (A).

  Examples of the polyester polyol (a12) include condensed polyester polyols, polylactone polyols, polycarbonate polyols, and castor oil-based polyols.

The condensed polyester polyol is a polyester polyol of a low molecular weight (less than Mn300) polyhydric alcohol and a polyvalent carboxylic acid having 2 to 10 carbon atoms or an ester-forming derivative thereof.
Low molecular weight polyhydric alcohols include dihydric to octahydric or higher aliphatic polyhydric alcohols less than Mn300 and alkylene oxides of dihydric to octavalent or higher phenols less than Mn300 (EO, PO, 1, 2). -, 1,3-, 2,3- or 1,4-butylene oxide and the like, hereinafter abbreviated as AO) and low molar adducts can be used.
Among the low molecular weight polyhydric alcohols that can be used in the condensed 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.

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

  Specific examples of the condensed polyester polyol include polyethylene adipate diol, polybutylene adipate diol, polyhexamethylene adipate diol, polyhexamethylene isophthalate diol, polyneopentyl adipate diol, polyethylene propylene adipate diol, polyethylene butylene adipate diol, polybutylene Hexamethylene adipate diol, polydiethylene adipate diol, poly (polytetramethylene ether) adipate diol, poly (3-methylpentylene adipate) diol, polyethylene azelate diol, polyethylene sebacate diol, polybutylene azelate diol, polybutylene seba Kate diol and polyneopentyl terephthalate diol It is.

  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], And Sanester 2620 [polyethylene adipate diol with Mn = 2,000, manufactured by Sanyo Chemical Industries, Ltd.].

The polylactone polyol is a polyaddition product of a lactone to the low molecular weight polyhydric alcohol. 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.

  Examples of the polycarbonate polyol include the low molecular weight polyhydric alcohol, a low molecular carbonate compound (for example, an alkyl group having 1 to 6 carbon atoms, an alkylene carbonate having an alkylene group having 2 to 6 carbon atoms, and 6 to 9 carbon atoms). And a polycarbonate polyol produced by condensation with a dealcoholization reaction. Two or more low molecular weight polyhydric alcohols and alkylene carbonates may be used in combination.

  Specific examples of the polycarbonate polyol include polyhexamethylene carbonate diol, polypentamethylene carbonate diol, polytetramethylene carbonate diol, and poly (tetramethylene / hexamethylene) carbonate diol (for example, 1,4-butanediol and 1,6-hexane). And a diol obtained by condensing a diol with a dialkyl carbonate while causing a dealcoholization reaction).

Examples of commercially available polycarbonate polyols include NIPPOLAN 980R [polyhexamethylene carbonate diol with Mn = 2,000, manufactured by Nippon Polyurethane Industry Co., Ltd.], NIPPOLAN 981 [polyhexamethylene carbonate diol with Mn = 1,000, Nippon Polyurethane Industry DURANOL G4672 [poly (tetramethylene / hexamethylene) carbonate diol with Mn = 2,000, manufactured by Asahi Kasei Chemicals Corporation], etanacol UH-200 [polyhexamethylene carbonate diol with Mn = 2,000] , Manufactured by Ube Industries, Ltd.] and etanacol UM-90 [poly [cyclohexylenebis (methylene) / hexamethylene] carbonate diol of Mn = 900, manufactured by Ube Industries, Ltd.].

  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.

  Among the polyester polyols (a12), preferred are condensed polyester polyols and polycarbonate polyols, and most preferred are polycarbonate diols.

  Examples of the low molecular polyol (a2) having a Mn of less than 300 include aliphatic dihydric alcohols, aliphatic trihydric alcohols and tetrahydric or higher aliphatic alcohols. Among (a2), from the viewpoint of water resistance and heat-resistant yellowing, a divalent or trivalent aliphatic alcohol is preferable. Examples of the aliphatic dihydric alcohol include ethylene glycol, propylene glycol, and 1,4-butanediol. Neopentyl glycol and 1,6-hexanediol are particularly preferable, and trimethylolpropane is particularly preferable as the aliphatic trihydric alcohol.

  As the polyisocyanate (b), which is an essential component of the urethane resin (A), those conventionally used for the production of urethane resins can be used. The polyisocyanate (b) is an aromatic polyisocyanate (b1) having 2 to 3 or more isocyanate groups and having 6 to 20 carbon atoms (excluding carbon in the isocyanate group, the same shall apply hereinafter), and 2 to 2 carbon atoms. 18 aliphatic polyisocyanate (b2), alicyclic polyisocyanate (b3) having 4 to 15 carbon atoms, araliphatic polyisocyanate (b4) having 8 to 15 carbon atoms and derivatives of (b1) to (b4) ( For example, isocyanurate product).

  Examples of the aromatic polyisocyanate having 6 to 20 carbon atoms (b1) include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate (TDI), 4,4′-. Or 2,4′-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate, 4,4 ′, 4 ″ -triphenylmethane triisocyanate, m- or p-isocyanatophenylsulfonyl isocyanate, crude MDI, etc. Can be mentioned.

  Examples of the aliphatic polyisocyanate (b2) having 2 to 18 carbon atoms include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2 -Isocyanatoethyl-2,6-diisocyanatohexanoate and the like.

  Examples of the alicyclic polyisocyanate (b3) having 4 to 15 carbon atoms include isophorone diisocyanate (IPDI), 4,4-dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, and methylcyclohexylene diisocyanate (hydrogenated TDI). Bis (2-isocyanatoethyl) -4-cyclohexene-1,2-dicarboxylate, 2,5- or 2,6-norbornane diisocyanate, and the like.

  Examples of the aromatic aliphatic polyisocyanate (b4) having 8 to 15 carbon atoms include m- and / or p-xylylene diisocyanate (XDI), α, α, α ′, α′-tetramethylxylylene diisocyanate (TMXDI). Etc.

  Of the polyisocyanates (b), (b2) and (b3) are preferable from the viewpoint of mechanical properties and weather resistance of the resulting film, (b3) is more preferable, and IPDI and hydrogenated MDI are particularly preferable. is there.

Examples of the compound (c) containing a hydrophilic group and an active hydrogen atom include compounds containing an anionic group and an active hydrogen atom. An anionic group is mentioned as a hydrophilic group. Examples of the anionic group include a carboxyl group and a sulfonic acid group.
Examples of (c) include a carboxyl group as an anionic 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), tartaric acid and amino acids (for example, glycine, alanine and valine)], a sulfonic acid group as an anionic group, and having 2 to 2 carbon atoms. 16 compounds [3- (2,3-dihydroxypropoxy) -1-propanesulfonic acid and sulfoisophthalic acid di (ethylene glycol) ester and the like], containing a sulfamic acid group as an anionic group, and having 2 to 10 carbon atoms [N, N-bis (2-hydroxylethyl) sulfamic acid, etc.] and the like and these compounds are neutralized with a neutralizing agent Salt and the like.

Examples of the neutralizing agent used in the salt of (c) include ammonia, an amine compound having 1 to 20 carbon atoms, or an alkali metal hydroxide (such as sodium hydroxide, potassium hydroxide, and lithium hydroxide).
Examples of the amine compound having 1 to 20 carbon atoms include primary amines such as monomethylamine, monoethylamine, monobutylamine and monoethanolamine, secondary amines such as dimethylamine, diethylamine, dibutylamine, diethanolamine, diisopropanolamine and methylpropanolamine. Examples include amines and tertiary amines such as trimethylamine, triethylamine, dimethylethylamine, dimethylmonoethanolamine and triethanolamine.

  Among (c), 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid and salts thereof are preferable from the viewpoint of the resin physical properties of the obtained film and the dispersion stability of the composite particles for ink. More preferred are neutralized salts of 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid with ammonia or amine compounds having 1 to 20 carbon atoms.

Based on the weight of (A), the content of the hydrophilic group in (A) is preferably 0.01 to 3 mmol / g, more preferably 0.2 to 1% by weight, still more preferably 0.5 to Adjust to 0.8 mmol / g. The hydrophilic group is preferably the total amount of acid groups and neutralized acid anion groups.
The hydrophilic group content in the present invention does not include the weight of the counter ion. For example, the content of the hydrophilic group in (c) is, in the case of triethylamine salt of 2,2-dimethylolpropionic acid, the weight% of carboxyl group (—COOH), and 3- (2,3-dihydroxypropoxy). In the case of triethylamine salt of -1-propanesulfonic acid, it refers to the weight percent of the sulfo group (—SO 3 H).

  Examples of the chain extender (H) include water, diamines having 2 to 10 carbon atoms (for example, ethylenediamine, propylenediamine, hexamethylenediamine, isophoronediamine, toluenediamine and piperazine), and polyalkylenepolyamines having 2 to 10 carbon atoms ( For example, diethylenetriamine and triethylenetetramine), hydrazine or a derivative thereof (dibasic acid dihydrazide such as adipic acid dihydrazide), polyepoxy compound having 2 to 30 carbon atoms (for example, 1,6-hexanediol diglycidyl ether, trimethylolpropane poly) Glycidyl ether and the like) and amino alcohols having 2 to 10 carbon atoms (for example, ethanolamine, diethanolamine, 2-amino-2-methylpropanol, and triethanolamine).

  As the reaction terminator (d), 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).

  Urethane resins may be used alone or in combination of two or more.

  The urethane resin (A) 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 (A).

<Polymer (F)>
In the present invention, the polymer (F) is a polymer having a group (j) having reactivity with an isocyanate group, and at least a monomer (f) having a group (j) having reactivity with an isocyanate group. May be included as an essential constituent monomer, and the monomer (g) may be used as a constituent monomer.

Examples of the group (j) having reactivity with an isocyanate group include a hydroxyl group and an amino group. Of these, a hydroxyl group is preferred.

  Examples of the monomer (f) include the following examples, and two or more types may be used in combination.

Monomer (f1) wherein (j) is a hydroxyl group
Hydroxystyrene, N-methylol (meth) acrylamide, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, (meth) allyl alcohol, crotyl alcohol, isocrotyl alcohol, 1- Buten-3-ol, 2-buten-1-ol, 2-butene-1,4-diol, propargyl alcohol, 2-hydroxyethylpropenyl ether, sucrose allyl ether, and the like.

Monomer (f2) wherein (j) is an amino group
Aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, t-butylaminoethyl methacrylate, N-aminoethyl (meth) acrylamide, (meth) allylamine, morpholinoethyl (meth) acrylate, 4-vinylpyridine, 2-vinylpyridine, crotylamine, N, N-dimethylaminostyrene, methyl-α-acetaminoacrylate, vinylimidazole, N-vinylpyrrole, N-vinylthiopyrrolidone, N-arylphenylenediamine, aminocarbazole Aminothiazole, aminoindole, aminopyrrole, aminoimidazole, aminomercaptothiazole, and salts thereof.

Although there is no restriction | limiting in particular as a monomer (g), For example, the monomer which has a polymerizable double bond is mentioned. The concentration of the group (j) is preferably 0.01 to 0.3 mmol / g based on the weight of the pigment particles (B).

<Pigment particle (B)>
Examples of the pigment particles (B) used in the present invention include pigment particles containing inorganic pigments, organic pigments 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.

Further, the shape of the pigment particles (B) is not particularly limited, and examples thereof include granular shapes.
The weight ratio of the urethane resin (A) to the pigment particles (B) is preferably 1.2 or more and less than 4.0, and more preferably 1.4 or more and less than 3.5.

  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.

<Method for producing aqueous composite particle dispersion (Q) for ink>
The present invention includes the following steps:
(I) Monomer (f) and solvent (S) having pigment particles (B), liquid, subcritical or supercritical carbon dioxide (E), and groups (j) having reactivity with isocyanate groups The pigment particles (B) were impregnated into the pigment particles (B) and polymerized to cause the pigment particles (B) to be coated with the polymer (F) having the group (j). After forming the composite particles (C0), the carbon dioxide (E) in a liquid, subcritical or supercritical state is removed to thereby disperse the composite particles (C0) in the solvent (S) (G )
(Ii) forming a prepolymer (P) having an isocyanate group;
(Iii) reacting the dispersion (G) with a prepolymer (P) having an isocyanate group,
(Iv) a step of neutralizing with the neutralizing agent (D),
(V) a step of emulsifying the obtained neutralized product in water and performing a chain extension reaction with a chain extender (H) and then removing the solvent (S);
Is a method for producing an aqueous composite particle dispersion (Q) containing pigment particles coated with a urethane resin.
In addition, step (i)
(I ′) a monomer (f) having a pigment particle (B), a liquid, subcritical or supercritical carbon dioxide (E), a group (j) having reactivity with an isocyanate group, and a solvent ( S), and the pigment particles (B) are impregnated with the monomer (f), and then the carbon dioxide (E) in a liquid, subcritical or supercritical state is removed, and a polymerization reaction is performed, whereby a solvent is obtained. It may be a step of obtaining a dispersion (G) in which the composite particles (C0) in which the pigment particles (B) are coated with the polymer (F) having the group (j) in (S) are dispersed.
Hereinafter, each step will be described.

<Manufacturing process (i)>
In the present invention, in order to form the impregnation layer (M) on the pigment particles (B), a method using liquid, subcritical or supercritical carbon dioxide can be used. The components that form the impregnated layer by these methods need to penetrate from the surface of the pigment particles (B) to the inside. In order to penetrate, there is no particular limitation as long as it is non-crystalline or deficient and liquid, subcritical or supercritical carbon dioxide can penetrate.

  By impregnating the pigment particles (B) in the monomer (f), solvent (S) and liquid, subcritical or supercritical carbon dioxide and reacting the monomer (f) after impregnation or simultaneously The method of forming an impregnation layer (M) and a coating layer (M1) is mentioned.

  The volume average particle diameter (D50) of the composite particles (C0) can be adjusted by selecting the primary particle diameter of the pigment particles (B) and adjusting the amount of the monomer (f).

The solvent (S) in the present invention is not particularly limited as long as the pigment particles are present as a solid in the mixture. However, the solvent (S) is a liquid at room temperature and normal pressure, such as a ketone solvent (acetone, methyl ethyl ketone, etc.), an ether solvent, and the like. (Tetrahydrofuran, diethyl ether, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, cyclic ether, etc.), ester solvents (acetate ester, pyruvate ester, 2-hydroxyisobutyrate ester, lactate ester, etc.), amide solvent (dimethylformamide) Etc.), aromatic hydrocarbon solvents (toluene, xylene, etc.), aliphatic hydrocarbon solvents (octane, decane, etc.), and mixtures thereof.

In the present invention, if the pigment particles are present as a solid in the mixture, an inert gas may be used in combination to prepare other physical property values (viscosity, diffusion coefficient, dielectric constant, solubility, interfacial tension), for example. It doesn't matter.

  Examples of the inert gas include inert gases such as nitrogen, helium, argon, and air. The weight fraction of carbon dioxide in the total of carbon dioxide and other substances is preferably 70% by weight or more, more preferably 80% by weight or more, and particularly preferably 90% by weight or more.

  The initiator (I) that can be used for the polymerization of the monomer (f) is not particularly limited as long as it is soluble in a liquid, a subcritical or supercritical carbon dioxide, or a mixture with a solvent (S). However, the following compounds etc. are mentioned.

Initiator (I):
Examples of the photopolymerization initiator (I-1) include acetophenone derivatives, acylphosphine oxide derivatives, titanocene derivatives, and combinations thereof.
Examples of the acetophenone derivative include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, acetophenone, 2,2 -Dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, benzyldimethyl ketal, 2-hydroxy-2-methylpropiophenone, 4-isopropyl-2-hydroxy-2-methylpropiophenone, 2-methyl- 1- (4- (methylthio) phenyl) -2-morpholino-1-propanone, dimethylbenzyl ketal, methylbenzoyl formate, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) - butan-1-one] and the like.
Examples of the acylphosphine oxide derivative include 2,4,6, -trimethylbenzoyl-diphenyl-phosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide.
Examples of the titanocene derivative include bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium.
Examples of the thermal polymerization initiator (I-2) include azo polymerization initiators [for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2, 2'-azobis [N- (2-carboxyethyl) 2-methylpropionamidine] hydrate, 2,2'-azobis (2-methylpropionamidine) dihydrochloride, 2,2'-azobis [2- (2- Imidazolin-2-yl) propane] dihydrochloride, 1,1-azobis (1-acetoxy-1-phenylethane), dimethyl-2,2′-azobisisobutyrate, 4,4′-azobis-4-cyano Valeric acid, azobiscyanovaleric acid, etc.)], and organic peroxide polymerization initiators [for example, benzoyl peroxide, di-t-butyl peroxide, t-butyl peroxide] And xylbenzoate, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, etc.].
Examples of the acid generator (I-3) include an onium salt thermal acid generator, a sulfonium salt photoacid generator, an iodonium salt photoacid generator, a diazosulfonic acid photoacid generator, and a triphenylsulfonium light. An acid generator etc. are mentioned.
Examples of the base generator (I-4) include guanidinium derivatives, imidazole derivatives, piperidine derivatives, and carbamate derivatives.
Examples of the redox initiator (I-5) include persulfate, hydrogen peroxide, hydroperoxide, alkyl peroxide, diacyl peroxide and the like as the oxidizing agent, and iron (II) salt as the reducing agent, Examples thereof include sodium hydrogen sulfate, tertiary amine, naphthenate, mercaptan, triethylaluminum, alcohol, polyamine, and the like, and any oxidizing agent and reducing agent can be combined.

  In the step of forming the impregnated layer (M) on the pigment particles (B), together with the pigment particles, additives (dispersants, leveling agents, plasticizers, antistatic agents, Charge control agents, ultraviolet absorbers, antiblocking agents, heat stabilizers, flame retardants, fillers, etc.) may be used.

  If necessary, an additive (k) can be added to the dispersion (G) in which the composite particles (C0) are dispersed in the solvent (S).

Examples of the method for obtaining the dispersion liquid (G) in which the composite particles (C0) are dispersed in the solvent (S) include the following methods [1] to [5].
[1] Monomer (f) and solvent (S) having pigment particles (B), liquid, subcritical or supercritical carbon dioxide (E), and groups (j) having reactivity with isocyanate groups The pigment particles (B) were impregnated into the pigment particles (B) and polymerized to cause the pigment particles (B) to be coated with the polymer (F) having the group (j). After forming the composite particles (C0), the carbon dioxide (E) in a liquid, subcritical or supercritical state is removed to thereby disperse the composite particles (C0) in the solvent (S) (G ) Can be obtained.

[2] A pigment particle (B), a liquid, subcritical or supercritical carbon dioxide (E), and a monomer (f) having a group (j) having reactivity with an isocyanate group are mixed. The monomer (f) is dissolved, the monomer (f) is impregnated in the pigment particles (B), mixed with the solvent (S), and then carbon dioxide in a liquid, subcritical or supercritical state ( The composite particles (C0) in which the pigment particles (B) were coated with the polymer (F) having the group (j) in the solvent (S) were dispersed by removing E) and then performing a polymerization reaction. A dispersion (G) can be obtained.

[3] Pigment particles (B), liquid, subcritical or supercritical carbon dioxide (E) and initiator (I) are mixed, and the initiator (I) is dissolved in the mixture, and the initiator The pigment particles (B) are impregnated with (I), the unimpregnated initiator (I) is removed, and they have reactivity with isocyanate groups in liquid, subcritical or supercritical carbon dioxide (E) The monomer (f) having the group (j) and the solvent (S) are dissolved, the monomer (f) is impregnated in the pigment particles (B), and a polymerization reaction is performed, whereby the pigment particles (B) are obtained. After forming the composite particles (C0) coated with the polymer (F) having the group (j), the carbon dioxide (E) in a liquid, subcritical or supercritical state is removed, thereby removing the solvent (S). A dispersion liquid (G) in which the composite particles (C0) are dispersed can be obtained.

[4] The pigment particles (B), liquid, subcritical or supercritical carbon dioxide (E), and initiator (I) are mixed, and the initiator (I) is dissolved in the mixture, and the initiator The pigment particles (B) are impregnated with (I), the unimpregnated initiator (I) is removed, and they have reactivity with isocyanate groups in liquid, subcritical or supercritical carbon dioxide (E) The monomer (f) having a group (j) and the solvent (S) are dissolved, the monomer (f) is impregnated in the pigment particles (B), and then carbon dioxide in a liquid, subcritical or supercritical state Dispersion in which composite particles (C0) in which pigment particles (B) are coated with a polymer (F) having a group (j) are dispersed in a solvent (S) by removing (E) and causing a polymerization reaction A liquid (G) can be obtained.

[5] Pigment particles (B), liquid, subcritical or supercritical carbon dioxide (E) and initiator (I) are mixed, and the initiator (I) is dissolved in the mixture, and the initiator The pigment particles (B) are impregnated with (I), the unimpregnated initiator (I) is removed, and they have reactivity with isocyanate groups in liquid, subcritical or supercritical carbon dioxide (E) The monomer (f) having a group (j) is dissolved, the monomer (f) is impregnated in the pigment particles (B), mixed with the solvent (S), and then in a liquid, subcritical or supercritical state The carbon dioxide (E) is removed and the polymerization reaction is carried out to disperse the composite particles (C0) in which the pigment particles (B) are coated with the polymer (F) having the group (j) in the solvent (S). A dispersed liquid (G) can be obtained.

A known method can be used as the polymerization method, and there is no particular limitation. For example, thermal polymerization, polymerization that irradiates active energy rays such as ultraviolet rays or electron beams, polymerization using microwaves, oxidizing agent or reducing agent Polymerization using an acid or polymerization using an acid or a base can be used.

In the step of removing carbon dioxide (E) in a liquid, subcritical or supercritical state, it is preferable to depressurize the carbon dioxide in the kettle or to take out the contents and carbon dioxide in the kettle at the same time. From the viewpoint of mitigating, it is more preferable to depressurize the carbon dioxide in the kettle or simultaneously take out the contents and carbon dioxide in the kettle from the viewpoint that the amount of pressure change in the unit time of carbon dioxide coexisting with the contents is large.

Mixture (Y) comprising monomer (f) having a group (j) having reactivity with pigment particles (B) and an isocyanate group and solvent (S), and a liquid, subcritical or supercritical state Carbon dioxide (E) can be mixed by batch mixing method or continuous mixing method, but the line blending (in-line mixing) method, which is a continuous mixing method, improves productivity and quality. Is particularly preferable from the standpoints of making the temperature constant and reducing the manufacturing space

As a specific example of the apparatus used for the batch type mixing method, a mixer such as a pressure vessel is cited. There is no limitation on the length and diameter of the mixer portion of the apparatus and the number of mixing apparatuses (elements), but it must be able to withstand the pressure and temperature at which carbon dioxide becomes liquid or supercritical. It is preferable to provide a nozzle for taking out the mixture (Y) at the outlet of the apparatus used in the batch type mixing method.

Specific examples of apparatuses used for the line blending method include static inline mixers such as static mixers, inline mixers, lamond super mixers, and sulzer mixers, and stirring inline mixers such as vibrator mixers and turbo mixers. It is done. There is no limitation on the length and diameter of the mixer portion of the apparatus and the number of mixing apparatuses (elements), but it must be able to withstand the pressure and temperature at which carbon dioxide is in a liquid or supercritical state.
The outlet of the apparatus used for the line blending method is preferably provided with a nozzle for taking out the mixture (Y), similar to the pressure vessel.

An apparatus used for such a line blending method will be described with reference to the drawings.
FIG. 1 is a flowchart of an apparatus for producing composite particles for ink (C0) in a mixing method using line blending according to the present invention.
As a method for mixing the mixture (Y) with carbon dioxide (E) in a liquid, subcritical or supercritical state, first, a compressive fluid is mixed in a device that performs line blending from a carbon dioxide cylinder B1 through a carbon dioxide pump P2 (static). Introduced into the mixer M1) and adjusted to a pressure and temperature at which carbon dioxide becomes liquid or supercritical, and then the mixture (Y) is transferred from the dissolution tank T1 through the solution pump P1 to liquid, subcritical or supercritical dioxide. It is preferable to introduce into carbon (E).
The temperature at which line blending is performed is the same as in the case of mixing using the above-described pressure vessel. The residence time in the apparatus is not particularly limited as long as mixing is sufficiently performed, but is preferably 0.1 to 1800 seconds.
Next, by opening the valve V1 leading to the pressure receiving tank T2, the mixture (Y) after the line blend is decompressed and expanded to atmospheric pressure, and the compressible fluid is vaporized and removed, so that the dispersoid becomes a polymerizable monomer. A dispersion liquid dispersed therein is obtained.

<Manufacturing process (ii)>
In the present invention, as a method for forming the prepolymer (P) having an isocyanate group, the polyol (a), the polyisocyanate (b) a compound (c) containing a hydrophilic group and an active hydrogen atom is used to form an organic solvent. The method of forming in presence exists.

  In this method, the urethane prepolymer (P) comprises a polyol (a), a hydrophilic group and a compound (c) containing an active hydrogen atom in the presence or absence of an organic solvent (S) and an active hydrogen-containing group. It is formed by the urethanization reaction at a ratio in which the equivalent ratio of isocyanate groups to (excluding carboxyl groups, sulfo groups and sulfamic acid groups) is preferably 1.01 to 3, more preferably 1.1 to 2.

  In this invention, urethane prepolymer (P) is obtained by heating and reacting with the equipment which can be heated. For example, the raw material (P) is charged in a container and uniformly stirred, and then heated without stirring in a heating dryer or heating furnace, a simple pressure reactor (autoclave), Kolben, uniaxial or biaxial kneading. And a method of reacting by heating with stirring or kneading in a machine, a plast mill or a universal kneader. Among them, the method of reacting by heating while stirring or kneading increases the homogeneity of the obtained polyurethane resin (U), and the mechanical properties, durability, chemical resistance, scratch resistance and resistance of the resulting film. This is preferable because blocking properties and the like tend to be more excellent.

  The reaction temperature for producing the polyurethane resin (A) and the urethane prepolymer (P) is preferably 60 to 120 or 180 to 250 ° C. from the viewpoint of the content of allophanate groups and burette groups of the polyurethane resin (A). More preferably, it is 60-110 degreeC or 180-240 degreeC, Most preferably, it is 60-100 degreeC or 180-230 degreeC. If it is 120 degrees C or less, it is hard to produce | generate an allophanate group and burette group, and if it is 180 degrees C or more, an allohanate group and burette group will decompose | disassemble easily. The time for producing (A) 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, (A) which can fully exhibit the effect of the present invention will be obtained.

  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 (A). %.

<Manufacturing process (iii)>
In the present invention, the reaction between the prepolymer (P) and the dispersion (G) in which the composite particles (C0) are dispersed in the solvent (S) can be performed by heating with a heatable facility. For example, (P) and dispersion liquid (G) are charged in a container and uniformly stirred, and then heated without stirring in a heating dryer or heating furnace, or a simple pressure reactor (autoclave), Kolben, uniaxial or Examples thereof include a method of reacting by heating with stirring or kneading in a biaxial kneader, plast mill or universal kneader.

  The reaction temperature of the dispersion liquid (G) in which the composite particles (C0) are dispersed in the prepolymer (P) and the solvent (S) is determined from the viewpoint of the contents of allophanate groups and burette groups of the polyurethane resin (A). 60-120 or 180-250 degreeC is preferable, More preferably, it is 60-110 degreeC or 180-240 degreeC, Most preferably, it is 60-100 degreeC or 180-230 degreeC. If it is 120 degrees C or less, it is hard to produce | generate an allophanate group and burette group, and if it is 180 degrees C or more, an allohanate group and burette group will decompose | disassemble easily. Moreover, although reaction time can be suitably selected according to the installation to be used, it is generally preferably 1 minute to 100 hours, more preferably 3 minutes to 30 hours, and particularly preferably 5 minutes to 20 hours. .

<Manufacturing process (iv)>
If necessary, the hydrophilic group part introduced by (c) of the prepolymer is neutralized with a neutralizing agent (D). The neutralizing agent (D) 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.

Examples of the neutralizing agent (D) used in the salt of (c) include ammonia, an amine compound having 1 to 20 carbon atoms, or an alkali metal hydroxide (such as sodium hydroxide, potassium hydroxide, and lithium hydroxide). It is done.
Examples of the amine compound having 1 to 20 carbon atoms include primary amines such as monomethylamine, monoethylamine, monobutylamine and monoethanolamine, secondary amines such as dimethylamine, diethylamine, dibutylamine, diethanolamine, diisopropanolamine and methylpropanolamine. Examples include amines and tertiary amines such as trimethylamine, triethylamine, dimethylethylamine, dimethylmonoethanolamine and triethanolamine.

<Manufacturing process (v)>
As a method of emulsifying a neutralized product of the dispersion liquid (G) in which the composite particles (C0) are dispersed in the prepolymer (P) and the solvent (S), for example, an organic solvent (s) and dispersion may be used as necessary. Dispersed in an aqueous medium in the presence of the agent (e), the chain extender (H) and the reaction terminator (d) and reacted until the isocyanate groups are substantially eliminated [chain extension by (H), and if necessary ( The reaction is stopped by d)], and the organic solvent (s) used is distilled off if necessary.

  Examples of the organic solvent (s) 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 resin (P).

The aqueous medium in the present invention means water and a mixture of water and the organic solvent (s). The organic solvent used in the aqueous medium is preferably a water-soluble organic solvent from the viewpoint of dispersibility. When the organic solvent (s) is used, it may be distilled off if necessary during and / or after the production of the aqueous composite particle (C) dispersion for ink.

  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.

The method of the apparatus for dispersing the neutralized product of the dispersion (G) in which the composite particles (C0) are dispersed in the prepolymer (P) and the solvent (S) in an aqueous medium is not particularly limited. (1) Vertical stirring method, (2) Rotor-stator method [for example, homomixer (manufactured by ASONE)], (3) Line mill method [for example, line flow mixer], (4) Stationary tube mixing method [for example Static mixer], (5) Vibration type [for example, “VIBRO MIXER” (manufactured by Chilling Industries Co., Ltd.)], (6) Ultrasonic impact type [for example, ultrasonic homogenizer], (7) High pressure impact type [for example, Gaurin homogenizer (Gaurin) Etc.)], (8) membrane emulsification type [for example, membrane emulsification module], and (9) centrifugal thin film contact type [for example, “Filmix” (manufactured by Plymix)]. Of these, (2) is preferable.

The weight ratio of the urethane resin (A) to the pigment particles (B) in the coating step of the urethane resin (A) to the pigment particles (B) in the production steps (i) to (v) is preferably 1.2 or more and 4.0. Less, more preferably 1.4 or more and less than 3.5.

  Hereinafter, the preparation of the aqueous ink (X) using the aqueous composite particle dispersion for ink (Q) 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 contents of the viscosity modifier, antifoaming agent, antiseptic, deterioration preventing agent, stabilizer and antifreezing agent are each preferably 5% by weight or less, more preferably 3% by weight or less, based on the weight of the aqueous paint. is there.

  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 aqueous ink (X) using the aqueous composite particle dispersion (Q) for ink of the present invention is produced by mixing and stirring the above-described aqueous composite particle dispersion for ink (Q) of the present invention. Is done. 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 ink composite particles (C) or the ink composition (Q) containing the composite particles for ink of the present invention includes an offset printing ink, a relief printing ink, a gravure printing ink, a silk printing ink, an inkjet recording ink, It can be used for applications such as color filters.

  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>
OT-azo 15 (1,1-azobis (1-acetoxy-1-phenylethane): manufactured by Otsuka Chemical) (I-1) (0.4 part), carbon black (carbon black MA230 manufactured by Mitsubishi Chemical Corporation) (B -1) (12.6 parts), hydroxyethyl methacrylate (f-1) (3.9 parts), butyl methacrylate (g-1) (3.9 parts), methyl ethyl ketone (S-1) (47.8 parts) ) Was charged to 60% of the vessel volume in a reaction pressure vessel equipped with a stirrer and a thermometer, sealed, and the air inside was replaced with carbon dioxide, and then carbon dioxide was injected to make 8 MPa. Then, after stirring for 15 minutes at 40 ° C., the dispersion was obtained by discharging into a pressure-resistant receiving tank from a nozzle attached to the lower part of the container while keeping the pressure and temperature constant.
The obtained dispersion (50 parts) was put into a 200 ml glass reaction vessel, and after substitution with nitrogen under stirring, a polymerization reaction was carried out at 80 ° C. for 2 hours. After cooling to room temperature, the dispersant Azisper BP881 (k-1) (2.5 parts: manufactured by Ajinomoto Fine Techno Co., Ltd.) was added and stirred for 30 minutes to homogenize, and the methyl ethyl ketone dispersion (G- 1) was obtained. The hydroxyl group concentration in carbon black was 0.11 mmol / g.

  In a simple pressure reactor equipped with a stirrer and a heating device, etanacol UH-200 (polyhexamethylene carbonate diol of Mn = 2,000: manufactured by Ube Industries, Ltd.) (a-1) (379 parts), 2 , 2-dimethylolpropionic acid (c-1) (48.5 parts), 4,4′-dicyclohexylmethane diisocyanate (b-1) (222 parts) and methyl ethyl ketone (350 parts) were charged. Subsequently, the mixture was heated to 90 ° C. and subjected to urethanization reaction for 10 hours to produce a urethane prepolymer (P-1) having an isocyanate group.

To a methyl ethyl ketone solution (39 parts) of the obtained urethane prepolymer (P-1), a methyl ethyl ketone dispersion (G-1) (100 parts) of a hydroxyl group-containing carbon black is added, heated to 60 ° C., and reacted for 5 hours. went. While stirring at 40 ° C., triethylamine (D-1) (1.4 parts) was added, homogenized at 60 rpm for 30 minutes, and then water (7.8 parts) with a homomixer [manufactured by ASONE]. After emulsification, diethylenetriamine (H-1) (6.8 parts) as a chain extender was added, methyl ethyl ketone was distilled off at 70 ° C. for 8 hours under reduced pressure, and an aqueous composite particle aqueous dispersion (Q- 1) was obtained.

<Examples 2-3>
For Examples 2 to 3, composite particle aqueous dispersions (Q-2) to (Q-3) for ink were obtained in the same manner as in Example 1 using the raw materials described in Tables 1 and 2.

表中、単位を指定していない数字は仕込みの部数を示す。

In the table, the number that does not specify the unit indicates the number of copies prepared.

In addition, the composition of the raw material represented by the trade name in Tables 1 and 2 is as follows.
PTMG2000: Polytetramethylene glycol with Mn = 2,000 PPG2000: Polypropylene glycol with Mn = 2,000

<Examples 6 to 11>
Ion-exchanged water, ethylene glycol monobutyl ether, and ink composite particle aqueous dispersions (Q-1) to (Q-5) were charged in the number of parts listed in Table 3, mixed for 15 minutes, and water-based inks (X-1) to ( X-6) was obtained.

表中、単位を指定していない数字は仕込みの部数を示す。

In the table, the number that does not specify the unit indicates the number of copies prepared.

<Comparative Example 1>
In a simple pressure reactor equipped with a stirrer and a heating device, etanacol UH-200 (379 parts), 2,2-dimethylolpropionic acid (48.5 parts), 4,4′-dicyclohexylmethane diisocyanate (222 parts) ) And methyl ethyl ketone (350 parts). Then, it heated at 90 degreeC and urethanation reaction was performed for 10 hours, and the urethane prepolymer (P'-1) which has an isocyanate group was manufactured. This was added with triethylamine (36 parts) with stirring at 40 ° C., homogenized at 60 rpm for 30 minutes, and then emulsified with water (1080 parts) using a homomixer [manufactured by ASONE], and then a chain extender. Diethylenetriamine (175 parts) was added, and methyl ethyl ketone was distilled off at 65 ° C. under reduced pressure for 8 hours to obtain an aqueous polyurethane resin dispersion (U′-1).

<Comparative Example 4>
Ion-exchanged water (3 parts), carbon black water dispersion (“Aqua-Black 162”, Tokai Carbon Co., Ltd., solid content 20 wt%) (15 parts), ethylene glycol monobutyl ether (60 parts) and polyurethane resin aqueous dispersion The body (U′-1) (22 parts) was charged and mixed for 15 minutes to obtain an aqueous ink (X′-1).

<Comparative example 2>
Mix 20.0 g carbon black, 7.0 mmol ((4-aminobenzoylamino) -methane-1,1-diyl) bisphosphonic acid monosodium salt, 20.0 mmol nitric acid, and 200.0 mL pure water. did. And it mixed at 6,000 rpm at room temperature using the Silverson mixer. After 30 minutes, 20.0 mmol of sodium nitrite dissolved in a small amount of water was slowly added to the mixture. By this mixing, the temperature of the mixture reached 60 ° C., and the reaction was performed in this state for 1 hour. Thereafter, the pH of the mixture was adjusted to 10 using an aqueous sodium hydroxide solution. After 30 minutes, 20.0 mL of pure water was added, and diafiltration was performed using a spectrum membrane. After performing ion exchange treatment and replacing the counter ion of the anionic group of the self-dispersing pigment from sodium ion to potassium ion, the concentration of pigment solid content was adjusted to obtain a pigment dispersion (G′-1). The pigment dispersion (G′-1) contains a self-dispersed pigment having a ((4-aminobenzoylamino) -methane-1,1-diyl) bisphosphonic acid group having a counter ion of potassium bonded to the particle surface. The pigment content was 30.0%.

Under a nitrogen atmosphere, 186.0 parts HDI, 14.0 parts isopropanol, and 0.1 part tin-based catalyst are added to a reactor equipped with a stirrer, thermometer, cooler, and nitrogen gas inlet tube. The mixture was reacted at a temperature of 80 ° C. for 2 hours to urethanize to obtain a reaction solution. 0.01 parts of 2-ethylhexanoic acid zirconium (allophanatization catalyst) was added to the obtained reaction liquid and reacted at a temperature of 100 ° C. to obtain a reaction liquid. Unreacted HDI was removed by distilling the obtained reaction liquid with a thin-film distillation apparatus to obtain a urethane prepolymer (P′-2) having an isocyanate group. The obtained urethane prepolymer (P′-2) had an allophanate structure, and the isocyanate group content was 20.0%.

  In a four-necked flask equipped with a stirrer, a thermometer, a nitrogen gas inlet tube, and a reflux tube, 57.1 parts of urethane prepolymer (P′-2), 136 parts of polypropylene glycol having a molecular weight of 2000, and 300 parts of methyl ethyl ketone were added. The mixture was allowed to react at a temperature of 80 ° C. for 7 hours under a nitrogen gas atmosphere. The amount of urethane prepolymer (P′-2) and polypropylene glycol having a molecular weight of 2000 was determined so that “the number of moles of isocyanate groups”> “the number of moles of hydroxy groups or amino groups”. Subsequently, 2.4 parts of 2,2-dimethylolpropionic acid, 3.8 parts of trimethylolpropane, and 0.4 part of ethylenediamine were added and reacted at a temperature of 80 ° C. to obtain a reaction solution. After cooling the obtained reaction liquid to a temperature of 40 ° C., ion exchange water was added, and an aqueous potassium hydroxide solution was added while stirring at high speed with a homomixer to obtain a liquid containing a resin. From the obtained liquid, methyl ethyl ketone was distilled off under reduced pressure by heating to obtain an aqueous polyurethane resin dispersion (U′-2) having a urethane resin (solid content) content of 42.9%.

<Comparative Example 5>
Charge ion exchange water (14 parts), ethylene glycol monobutyl ether (60 parts), pigment dispersion (G′-1) (10 parts) and polyurethane resin aqueous dispersion (U′-2) (16 parts), 15 Mixing for a minute, an aqueous ink (X′-2) was obtained.

<Comparative Example 3 and Comparative Example 6>
OT-azo 15 (1,1-azobis (1-acetoxy-1-phenylethane): manufactured by Otsuka Chemical) (I-1) (0.4 parts), carbon black (B-1) (12.6 parts: Carbon black MA230 manufactured by Mitsubishi Chemical Corporation), hydroxyethyl methacrylate (f-1) (3.9 parts), butyl methacrylate (g-1) (3.9 parts), methyl ethyl ketone (S-1) (47.8 parts) Was charged in a pressure-resistant reaction vessel equipped with a stir bar and a thermometer to 60% of the vessel volume, and stirred at 40 ° C. for 1 hour to obtain a dispersion.
The obtained dispersion (50 parts) was put into a 200 ml glass reaction vessel, and after substitution with nitrogen under stirring, a polymerization reaction was carried out at 80 ° C. for 2 hours. After cooling to room temperature, Azisper BP881 (k-1) (2.5 parts: manufactured by Ajinomoto Fine-Techno) was added and stirred for 30 minutes to homogenize, and the methyl ethyl ketone dispersion (G′-2) of hydroxyl group-containing carbon black ) The hydroxyl group concentration in carbon black was 0.11 mmol / g.

Subsequently, aqueous ink composite particle dispersions (Q′-1) and (X′-3) were obtained in the same manner as in Example 1.

  Table 4 shows the evaluation results using the water-based inks (X-1) to (X-6) and (X′-1) to (X′-3) obtained in Examples 4 to 9 and Comparative Examples 4 to 6. Shown in In addition, the evaluation method as a water-based ink in the present invention is as follows.

<Particle size>
The aqueous ink was diluted with ion-exchanged water so that the solid content of the polyurethane resin was 0.01% by weight, and then measured using a nanoparticle analyzer SZ-100 manufactured by Horiba.

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

<Ink storage stability>
The prepared ink was put in a screw tube and stored at 70 ° C. for 1 week, and the state of thickening and aggregation was evaluated by the rate of change in viscosity before and after storage.

<Abrasion resistance>
The obtained water-based ink was applied to a 5 cm × 10 cm PVC film with a bar coater so that the film thickness after drying was 2 μm, and heated at 80 ° C. for 10 minutes to produce a printed matter. The printed surface was rubbed 50 reciprocally with a load of 200 g with an unprinted PVC film using a Gakushin friction tester, and then visually evaluated according to the following criteria.
(Double-circle): The image density of a printing surface does not change, and a color transfer does not move to the PVC film which is not printed.
◯: No change in the image density on the printed surface is observed, but a slight color transfer is observed on the unprinted PVC film.
(Triangle | delta): The image density of a printing surface falls.
X: The ink on the printing surface is peeled off.

<Image density>
The obtained water-based ink was applied to a 5 cm × 10 cm PVC film with a bar coater so that the film thickness after drying was 2 μm, and heated at 80 ° C. for 10 minutes to produce a printed matter. The printed surface was measured with an image densitometer (manufactured by GretagMacbeth).

<Glossiness>
The obtained water-based ink was applied to a 5 cm × 10 cm PVC film with a bar coater so that the film thickness after drying was 2 μm, and heated at 80 ° C. for 10 minutes to produce a printed matter. The 60 ° glossiness of the printed surface was measured with a gloss meter (manufactured by BYK).

<Method for evaluating solvent resistance of printed matter>
The obtained water-based ink was applied to a 5 cm × 10 cm PVC film with a bar coater so that the film thickness after drying was 2 μm, and heated at 80 ° C. for 10 minutes to produce a printed matter. A cotton swab was soaked with ethanol water, a load of 50 g was applied, and the maximum concentration of ethanol water in which peeling of the printed matter was not observed even after rubbing the printed surface 5 times was evaluated.

  As shown in Table 4, water-based inks (X-1) to (X-3), (X-5), and (X-6) containing the composite particle dispersion for ink of the present invention described in Examples are It can be seen that the resin concentration and the pigment concentration are equivalent to those of the inks (X′-1) to (X′-3) of the comparative example, but the viscosity is reduced. Further, it can be seen that the water-based ink (X-4) in which the resin concentration and the pigment concentration are increased by 1.5 times has the same viscosity as that of the comparative example, and has excellent scratch resistance and image density. Aqueous inks (X-1) to (X-6) containing the composite particle dispersion for ink of the present invention described in Examples are compared with inks (X′-1) to (X′-3) of Comparative Examples. It can be seen that the storage stability, 60 ° gloss, and solvent resistance are excellent.

The ink composite particle or the ink composition containing the composite particle for ink of the present invention is used for applications such as offset printing ink, relief printing ink, gravure printing ink, silk printing ink, inkjet recording ink, and color filter. Can be used.

Claims (10)

  A composite particle comprising a urethane resin (A) and pigment particles (B), the surface of the pigment particles (B) being coated with a coating layer (L) containing the urethane resin (A), and the pigment particles ( B) has an impregnation layer (M) impregnated with a polymer (F) having a group (j) having reactivity with an isocyanate group from the surface to the inside, and the polymer (F) and the urethane resin ( A composite particle for ink (C) in which A) is bonded by a covalent bond, and the average thickness of the impregnated layer (M) is 0.1% to 50% of the volume average particle diameter of the composite particle.   The composite particle for ink (C) according to claim 1, wherein the group (j) is a hydroxyl group.   The composite particle for ink (C) according to claim 1 or 2, wherein the volume average particle diameter is 10 nm or more and 800 nm or less.   The composite particle for ink (C) according to any one of claims 1 to 3, wherein the urethane resin (A) is an anionic urethane resin having an acid group and / or a neutralized acid anion group.   The composite particle for ink (C) according to any one of claims 1 to 4, comprising a polycarbonate diol as an essential constituent monomer of the urethane resin (A).   The composite particle for ink (C) according to any one of claims 1 to 5, wherein the weight ratio of the urethane resin (A) to the pigment particle (B) is in a range of 1.2 to 4.0.   An ink composite particle aqueous dispersion (Q) comprising the ink composite particles (C) according to any one of claims 1 to 6 and water.   An aqueous ink (X) comprising the aqueous composite particle dispersion (Q) for ink according to claim 7. Pigment particles (B), liquid, subcritical or supercritical carbon dioxide (E), a monomer (f) having a group (j) having reactivity with an isocyanate group, and a solvent (S) By mixing, impregnating the monomer particles (f) into the pigment particles (B) and performing a polymerization reaction, the composite particles in which the pigment particles (B) are coated with the polymer (F) having the group (j) ( After forming C0), carbon dioxide (E) in a liquid, subcritical or supercritical state is removed to obtain dispersion (G) in which composite particles (C0) are dispersed in solvent (S). And
Subsequently, after making this dispersion liquid (G) and the prepolymer (P) which has an isocyanate group react, it neutralizes with a neutralizing agent (D), the obtained neutralized material is emulsified in water, and a chain | strand is obtained. Including a step of removing the solvent (S) after the chain extension reaction with the extender (H).
A method for producing an aqueous composite particle dispersion (Q) containing ink composite particles (C) which are pigment particles coated with a urethane resin. Pigment particles (B), liquid, subcritical or supercritical carbon dioxide (E), a monomer (f) having a group (j) having reactivity with an isocyanate group, and a solvent (S) Mixing, impregnating the monomer particles (f) into the pigment particles (B), then removing the liquid, subcritical or supercritical carbon dioxide (E), followed by polymerization reaction, the solvent (S ) To obtain a dispersion liquid (G) in which composite particles (C0) in which pigment particles (B) are coated with a polymer (F) having a group (j) are dispersed,
Subsequently, after making this dispersion liquid (G) and the prepolymer (P) which has an isocyanate group react, it neutralizes with a neutralizing agent (D), the obtained neutralized material is emulsified in water, and a chain | strand is obtained. An aqueous composite particle dispersion for ink containing composite particles for ink (C), which are pigment particles coated with urethane resin, comprising a step of removing the solvent (S) after a chain extension reaction with the extender (H) Manufacturing method of body (Q).

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