JP2006282732A - Manufacturing method of water-based pigment dispersion for inkjet printer, and water-based pigment recording liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a water-based pigment dispersion for preparing a water-based pigment recording liquid exhibiting excellent jetting stability in a thermal inkjet printer, and the water-based pigment recording liquid. <P>SOLUTION: The manufacturing method of the water-based pigment dispersion for inkjet printers comprising a copper phthalocyanine pigment coated with an organic polymer compound having a neutralized anionic group comprises finely dispersing the copper phthalocyanine by feeding a dispersion, using a dispersion medium agitation type dispersing apparatus having a rotor and a separator in a cylindrical grinding part as the dispersion apparatus, so that the applied energy efficiency in the dispersing apparatus is 15-25 kwh/kg. The water-based pigment recording liquid is prepared from the water-based pigment dispersion. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a useful method for producing an aqueous pigment dispersion for an ink jet printer and an aqueous pigment recording liquid.

  Conventionally, dyes have been used as coloring materials for writing instruments such as sign pens and water-based markers and ink for ink jet printers. However, although the aqueous recording liquid using a dye is excellent in coloring power and image sharpness, there is a problem that the water resistance and light resistance of the printed matter are inferior. In order to improve this water resistance and light resistance, in recent years, the conversion from dyes to pigments has been actively studied in the above-mentioned applications.

  Aqueous pigment recording liquids for inkjet printers are required to have various characteristics, especially in thermal ink jet printers that have a heater and use the pressure of firing due to rapid heating of the heater. This causes the problem of kogation and causes a problem that the liquid cannot be discharged (non-discharge), so that the discharge stability of the aqueous recording liquid is required.

In Patent Document 1, an aqueous pigment dispersion finely dispersed with a resin having a carboxyl group neutralized with a basic compound is used to make the resin hydrophobic by setting the pH to neutral or acidic using an acidic compound. By firmly fixing the resin to the pigment (so-called acid precipitation), and then, if necessary, after filtering and washing with water, neutralize the carboxyl group again with a basic compound and redisperse in water. It is described that it is possible to obtain an aqueous pigment dispersion that is finely dispersed to a degree sufficient to exhibit gloss, color developability, and coloring power and that is excellent in storage stability.
However, in order to add printing characteristics as an ink to an aqueous pigment recording liquid for an ink jet printer, ethylene glycol, glycerin, a pH adjuster, an activator, and the like are generally added. Even with the obtained aqueous pigment dispersion, for example, an aqueous pigment recording liquid for an ink jet printer manufactured by a flow-type wet bead mill such as a pearl mill (PM-DCP type) cannot prevent the primary particles of the pigment from being crushed and stored. There is a drawback in that the viscosity of the liquid and the increase in the particle diameter are increased, and the discharge stability of the aqueous pigment recording liquid cannot be brought to a practical level.

Patent Document 2 discloses a method for producing an aqueous pigment recording liquid for an ink jet printer in which a pigment is coated with a neutralized organic polymer compound having an anionic group, and a rotor in a cylindrical pulverizing section is used as a dispersing device. Of preparing a water-based pigment recording liquid using a pigment dispersion liquid in which a pigment is finely dispersed so that the residence time in the dispersion apparatus is within 30 seconds using a dispersion medium stirring type dispersion apparatus having a separator and a separator Is described.
However, although this aqueous pigment recording liquid for ink jet printers can be obtained with the above highly practical aqueous pigment recording liquid having superior storage stability than that prepared with a pigment dispersion obtained using a conventional dispersing device, In view of recent market demand levels, the discharge stability was still insufficient.

Japanese Patent Laid-Open No. 9-31360 (the second column, the left column, claims, page 3, paragraph number 0014). Japanese Patent Laid-Open No. 11-166145 (page 2, left column, claims, page 4 paragraph numbers 0024 to 0025, page 15 paragraph number 0174).

  The problem to be solved by the present invention is a method for producing an aqueous pigment dispersion for preparing an aqueous pigment recording liquid for an inkjet printer having excellent ejection stability in a thermal ink jet printer, and the aqueous pigment dispersion obtained here Another object is to provide an aqueous pigment recording liquid containing the body.

  Therefore, as a result of intensive studies in view of the above circumstances, the inventors of the present invention have prepared a specific pigment by using a specific dispersing device in a method for producing an aqueous pigment dispersion for preparing an aqueous pigment recording liquid for an inkjet printer. A pigment dispersion is prepared by finely dispersing a specific pigment under dispersion conditions in which the applied energy efficiency per kg of pigment in the dispersion device is within a specific range, and the organic high-having neutralized anionic group obtained here is prepared. It has been found that the above-mentioned problems can be solved by producing an aqueous pigment dispersion for an ink jet printer in which a specific pigment is coated with a molecular compound, and the present invention has been completed.

  That is, the present invention is a method for producing an aqueous pigment dispersion for an ink jet printer in which a copper phthalocyanine pigment is coated with an organic polymer compound having a neutralized anionic group. When a suspension containing an organic polymer compound having a copper phthalocyanine pigment is mixed and the copper phthalocyanine pigment is finely dispersed to form a pigment dispersion, a suspension supply port and discharge port are used as a dispersion device. An inner wall having a separator and having a cylindrical outer fixed container (I) and a cylindrical rotor (II) which is provided in the interior thereof with a predetermined gap and is rotatable about a rotation axis. II) has a hollow liquid chamber inside the cylinder and can supply a suspension toward the liquid chamber. The slit facing the supply port and a plurality of liquid discharge holes on the cylindrical side wall leading to the outside of the liquid chamber A separator having a plurality of holes having a predetermined diameter smaller than that of the dispersion medium, the outer fixed container (I) being opposed to the circumferential outer wall surface of the rotor with a predetermined gap. The external fixed container (I) provided on the inner wall of the container, and the container (I) is supplied while rotating the rotor (II) using a dispersing device filled with a dispersion medium in the gap between the rotor and the separator. Suspension is supplied to the liquid chamber from the mouth to the slit of the rotor, and the suspension is discharged from the discharge hole by centrifugal force. When the suspension is supplied from the discharge port, the suspension is supplied so that the applied energy efficiency in the dispersion device is 15 to 25 kwh per 1 kg of the pigment, and the copper phthalocyanine pigment is finely dispersed to obtain the pigment dispersion. There is provided an inkjet printer aqueous pigment dispersion aqueous pigment recording liquid prepared from the production method and an aqueous pigment dispersion obtained from the manufacturing method of according to claim Rukoto.

According to the production method of the present invention, using a dispersion medium stirring type dispersion device having a rotor and a separator in a cylindrical pulverization unit, the applied energy efficiency in the dispersion device is in the range of 15 to 25 kwh per 1 kg of pigment. Thus, by producing an aqueous pigment dispersion for an inkjet printer from a pigment dispersion obtained by finely dispersing a copper phthalocyanine pigment, an aqueous pigment recording liquid prepared from the aqueous pigment dispersion obtained here is In a thermal ink jet printer, there is a particularly remarkable effect of being superior in ejection stability.
Therefore, the method for producing the aqueous pigment dispersion of the present invention and the aqueous pigment recording liquid prepared from the aqueous pigment dispersion obtained by the production method are optimal for inkjet printer applications.

  Hereinafter, the present invention will be described in detail.

  The present invention relates to a method for producing an aqueous pigment dispersion for an ink jet printer in which a copper phthalocyanine pigment is coated with an organic polymer compound having a neutralized anionic group, and an organic polymer having a neutralized anionic group. When a suspension containing a molecular compound and a copper phthalocyanine pigment is mixed, and the copper phthalocyanine pigment is finely dispersed to form a pigment dispersion, the specific energy applied in the specific dispersion device and the dispersion device is 1 kg of pigment. Is carried out under dispersion conditions such that a specific range described later is obtained.

  That is, examples of the dispersing apparatus used in the present invention include a dispersion medium stirring type dispersing apparatus having a rotor and a separator in a short cylindrical pulverizing section as shown in FIG.

  Hereinafter, description will be made with reference to FIG. The dispersing device that can be used in the present invention is an external fixed container (I) [hereinafter referred to as an external fixed container 1. ] In the form of a cylindrical rotor (II) [hereinafter referred to as cylindrical rotor 2] through a predetermined gap. ] Is provided so as to be rotatable around its rotation shaft 3. Although the direction of the rotating shaft 3 is arbitrary, it is preferable for the reason described later that it is horizontal, that is, a relationship parallel to the ground surface. In FIG. 1, it is shown in a preferred orientation. Further, the container 1 is provided with a supply port 4 and a discharge port 9 for supplying a suspension containing a copper phthalocyanine pigment.

  A separator 8 having a plurality of holes with a predetermined diameter that can pass through when pigment particles in a suspension containing a copper phthalocyanine pigment have a predetermined particle diameter is fixed to the inner wall of the external fixed container 1. The gap between the container 1 and the rotor 2 is filled with particles of a dispersion medium 7 having a predetermined diameter for pulverizing the copper phthalocyanine pigment in the suspension.

  On the other hand, a hollow liquid chamber 6 is provided inside the rotor 2 so that a suspension containing a copper phthalocyanine pigment supplied from the supply port 4 can be further supplied to the liquid chamber 6. A slit 5 made of a ring-shaped cut having a shape sandwiched between two circles having different radii around the rotation axis is provided. The slit 5 faces the supply port 4.

  The cylindrical side wall of the rotor 2 is provided with a plurality of liquid discharge holes (not indicated) that communicate with the liquid chamber 6 as indicated by arrows. Each liquid discharge hole of the rotor 2 has a larger diameter than the particles of the dispersion medium 7, and the suspension is discharged from the liquid discharge hole, while being provided in the separator 8. The diameter of each hole connected to the discharge port 9 is smaller than the particle of the dispersion medium 7 so that the dispersion medium 7 itself does not flow out to the discharge port 9.

  The outer circumferential wall surface of the rotor 2 and the separator 8 are opposed to each other, and the suspension is liquid in a gap between the container 1 and the rotor 2 filled with particles of the dispersion medium 7 from the liquid chamber 6. It is supplied through the discharge hole.

  The suspension is supplied from the supply port 4 through the slit 5 toward the liquid chamber 6 as indicated by an arrow. When the suspension 2 is supplied to the hollow liquid chamber 6 while the rotor 2 is rotated about the rotation shaft 3, the pigment is pulverized by the principle unique to the dispersing device.

  As a feature of the dispersing apparatus used in the present invention, when the rotor 2 is rotated, centrifugal force is generated, and the media 7 is pressed against the inner wall of the separator 8 in a layered manner. At the same time, a strong shearing force is generated between the media 7 by the rotational movement of the rotor 2. Furthermore, since the centrifugal force and the flow direction of the suspension containing the copper phthalocyanine pigment are the same, uniform pulverization / dispersion and discharge of the suspension at a large flow rate from the separator 8 are possible. The residence time of the sample can be shortened.

  The copper phthalocyanine pigment in the suspension released from the liquid discharge hole by centrifugal force is pulverized in the gap filled with the particles of the dispersion medium 7, and the pigment particles are smaller than the hole diameter provided in the separator 8. At this stage, it passes through the hole and is taken out from the discharge port 9 together with the liquid medium of the suspension. Thus, the pigment dispersion liquid in which the copper phthalocyanine pigment is finely dispersed is taken out to the discharge port 9. The reason why the rotating shaft 3 of the rotor 2 is horizontal is to use the effect of the centrifugal force more fully.

  The operating condition of the dispersing device used in the present invention is preferably such that the residence time of the sample in the dispersing device is 30 seconds or less / pass (pass). When the residence time of the sample becomes long, the primary particles of the copper phthalocyanine pigment tend to be crushed and a sharp particle size distribution cannot be obtained.

  Furthermore, the total stirring power (kwh) in the dispersing device that contributes to the dispersion of the copper phthalocyanine pigment and the pigment (kg) as the dispersion are indispensable for calculating the applied energy efficiency. The applied energy efficiency kwh / kg is determined from the relational expression of the total stirring power kwh / kg of pigment, and the numerical value is preferably in the range of 15-25 kwh / kg, and more preferably in the range of 17-22 kwh / kg. More preferably. Other conditions can be appropriately set depending on the type and amount of the dispersed sample, the target particle size distribution, and the like.

  In the present invention, as described above, a suspension containing a specific organic polymer compound and a specific pigment is passed (passed) through the specific dispersion device as described above, thereby dispersing the pigment in which the specific pigment is finely dispersed. A liquid can be obtained. The suspension is preferably supplied to the supply port 4 by a normal pump, and the suspension is preferably continuously supplied so that the liquid chamber 6 is always filled.

  In the case where a pigment dispersion in which the specific pigment is sufficiently finely dispersed cannot be obtained by only passing (passing) the suspension through the dispersion device, it is preferable to pass the suspension twice or more. The content of pigment particles smaller than the predetermined particle diameter smaller than the hole in the liquid medium is higher in the case where the pass is repeated twice or more than in the first pass. By repeating until the pigment particle content in the suspension passing through the dispersing device is saturated and constant, the particle diameter is smaller than the hole diameter of the separator 8 and pulverized to a predetermined particle diameter and finely dispersed in the liquid medium. A pigment dispersion in which pigment particles are uniformly and finely dispersed can be obtained.

  When the suspension is treated repeatedly to obtain a pigment dispersion, a container for holding the suspension and a circulation pump are further provided, and the pigment dispersion having a specific pigment having a predetermined particle diameter is provided. The liquid discharge port 9, the container for holding the suspension, the circulation pump, and the liquid supply port 4 are connected in this order, and the suspension is circulated so as to be within the above-mentioned stay time range. preferable.

  In the present invention, the type of the dispersion medium 7 filled between the container 1 and the rotor 2 is not particularly limited, and examples thereof include glass beads, oxidized zirconia beads, steel beads, and ceramic beads. Oxidized zirconia beads are preferred because of the hardness of the beads, rust in water, wear resistance, and the like. The filling amount of the beads is not particularly limited, but is preferably 20 to 50% of the gap internal volume as an example.

  As the size of the beads becomes finer, the dispersion ability increases, but a large pressure is required for separating the beads with a separator, and therefore, an appropriate range, for example, a diameter of 0.05 to 3 mm, preferably a diameter of 0.1. Use ~ 1 mm beads.

  Next, a suspension containing an organic polymer compound having a neutralized anionic group and a copper phthalocyanine pigment as a specific pigment used for obtaining the pigment dispersion of the present invention will be described.

  Examples of the copper phthalocyanine pigment used in the present invention include C.I. which is a conventionally known copper phthalocyanine pigment. I. Pigment Blue 15, C.I. I. Pigment Blue 15: 1, C.I. I. Pigment Blue 15: 2, C.I. I. Pigment Blue 15: 3, C.I. I. Pigment Blue 15: 4, C.I. I. Pigment Blue 15: 5, C.I. I. Pigment Blue 15: 6, C.I. I. Pigment Blue 17: 1 and the like. I. Pigment Blue 15: 3 or C.I. I. Pigment Blue 15: 4 is preferable. Furthermore, a conventionally known copper phthalocyanine pigment derivative can be appropriately used as the copper phthalocyanine pigment.

  These may be used as a powder, a wet cake, or an aqueous slurry. Furthermore, a water-soluble organic solvent can be used in combination as appropriate.

  As the organic polymer compound having an anionic group used in the present invention, known and commonly used compounds can be used. However, the organic polymer having an acid value (KOH mg / g) based on an anionic group in the range of 100 to 150 KOH mg / g. Molecular compounds are preferred. A typical example of the anionic group is a carboxyl group.

  Examples of such organic polymer compounds include vinyl copolymers, polyester resins, polyurethane resins, epoxy resins, and rosin-modified resins. Among these, vinyl copolymers, polyester resins and polyurethane resins are preferred from the viewpoints of ease of introduction of carboxyl groups and toughness of the coating.

  Examples of the vinyl copolymer used in the present invention include (meth) acrylic acid ester resin, (meth) acrylic acid ester-styrene copolymer resin, styrene- (anhydrous) maleic acid copolymer resin, and fluorine-containing resin. Examples thereof include vinyl copolymer resins.

  Examples of the polyester resin used in the present invention include saturated polyester resins, unsaturated polyester resins, and alkyd resins. These resins must contain a carboxyl group as an anionic group in order to impart moderate water solubility or water dispersibility.

  Examples of the polymerizable monomer having a carboxyl group include acrylic acid, methacrylic acid, crotonic acid, fumaric acid, itaconic acid, (anhydrous) maleic acid, monoalkyl maleates such as monobutyl maleate, and itacones such as monobutyl itaconic acid. Examples include acid monoalkyls, and acrylic acid, methacrylic acid and maleic acid are particularly preferable.

  Examples of the polymerizable vinyl monomer other than the polymerizable vinyl monomer having a carboxyl group contained in the polymerizable monomer composition include aromatic vinyl monomers such as styrene, vinyl toluene, and α-methylstyrene; ethyl acrylate, acrylic Acrylic acid esters such as n-butyl acid, methyl acrylate, 2-hydroxyethyl acrylate, methyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, isoamyl methacrylate, 2-methacrylic acid 2- Ethylhexyl, 2-hydroxyethyl methacrylate, isodecyl methacrylate, lauryl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, butoxymethyl methacrylate, ethoxydiethylene glycol methacrylate, Methacrylic acid esters such as benzyl crylate, cetyl methacrylate, tetrahydrofurfuryl methacrylate, isobornyl methacrylate; vinyl esters such as vinyl acetate, vinyl benzoate, vinyl versatic acid, vinyl propionate; and (meth) acrylonitrile Polymerizable nitriles; vinyl monomers having a fluorine atom such as vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene or chlorotrifluoroethylene; diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, N-vinylimidazole , Tertiary amino group-containing monomers such as N-vinylcarbazole; 2- (2′-hydroxy-5-methacryloyloxyethylphenyl) -2H-benzotriazole, 2 UV-absorbing or antioxidant monomers such as hydroxy-4- (2-methacryloyloxyethoxy) benzophenone, 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate; N-vinylpyrrolidone, methacryl Glycidyl acid, 1,3-dioxolan-2-one-4-ylmethyl methacrylate, 1,3-dioxolan-2-one-4-ylmethyl vinyl ether, diacetone acrylamide, N-methylol acrylamide, N-butoxymethyl (meta ) Functional group-containing monomers such as N-alkoxymethyl (meth) acrylamides such as acrylamide; Monomers having hydrolyzable alkoxysilane groups such as γ-methacryloxypropyltrimethoxysilane and vinyltrimethoxysilane; Methacrylic acid 2 − Phosphoric acid group-containing monomers such as sulfooxyethyl and 4-phosphooxybutyl methacrylate; macromonomers having one polymerizable unsaturated group at the molecular end, and the like. Particularly, 2-hydroxyethyl acrylate, 2-methacrylic acid 2- Hydroxyethyl and styrene are preferred.

  As the polymerization method for the polymerizable vinyl monomer composition, various known polymerization methods such as suspension polymerization, emulsion polymerization, bulk polymerization, and solution polymerization can be used. As the polymerization initiator, known peroxides and azo compounds can be used.

  The polyester resin having a carboxyl group used in the present invention is produced by subjecting a carboxyl group-containing compound and a hydroxyl group-containing compound to a dehydration condensation reaction by a known method such as a melting method or a solvent method so that the carboxyl group remains. Is done.

  The polyester resin is obtained by appropriately dehydrating and condensing a compound having a carboxyl group such as a monobasic acid, a dibasic acid, or a polybasic acid and a compound having a hydroxyl group such as a diol or a polyol, and Those using oils or fats or fatty acids are alkyd resins.

  The carboxyl group which the polyester resin used in the present invention has is mainly an unreacted carboxyl group derived from a dibasic acid or a polybasic acid constituting the polyester resin.

  Examples of the dibasic acid or polybasic acid include adipic acid, (anhydrous) succinic acid, sebacic acid, dimer acid, (anhydrous) maleic acid, (anhydrous) phthalic acid, isophthalic acid, terephthalic acid, tetrahydro (anhydrous) phthalate Examples thereof include acid, hexahydro (anhydride) phthalic acid, hexahydroterephthalic acid, 2,6-naphthalenedicarboxylic acid, (anhydrous) trimellitic acid, and (anhydrous) pyromellitic acid.

  Examples of compounds having a carboxyl group that can be used in addition to dibasic acids or polybasic acids include lower alkyl esters of acids such as dimethyl terephthalate; benzoic acid, p-tertiarybutylbenzoic acid, rosin, and hydrogenated rosin. Monobasic acids such as: fatty acids and oils and fats; macromonomers having 1 or 2 carboxyl groups at the molecular terminals; 5-sodium sulfoisophthalic acid and dimethyl esters thereof.

  Examples of the compound having a hydroxyl group include ethylene glycol, neopentyl glycol, propylene glycol, diethylene glycol, dipropylene glycol, 2-methyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1 , 4-butanediol, 1,3-propanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, 1,5-pentanediol, alkylene oxide adduct of bisphenol A, hydrogenated bisphenol A, hydrogenated Alkylene oxide adducts of bisphenol A, diols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol; glycerin, trimethylolpropane, trimethylolethane, diglycerin, pentaerythridine Polyols such as lithol and trishydroxyethyl isocyanurate; monoglycidyl compounds such as “Cardura E-10” (a glycidyl ester of a synthetic fatty acid manufactured by Shell Chemical Industry Co., Ltd.), a macromonomer having two hydroxyl groups at one molecular end And the like.

  In addition, when synthesizing a polyester resin, a compound having a hydroxyl group and a hydroxyl group such as castor oil, a hydroxyl group-containing fatty acid such as 12-hydroxystearic acid or oils; dimethylolpropionic acid, p-hydroxybenzoic acid, ε-caprolactone, etc. Etc. can also be used.

  Furthermore, a part of the dibasic acid can be replaced with a diisocyanate compound. As the polyester resin having a carboxyl group used in the present invention, a modified polyester resin obtained by grafting a polymerizable monomer having a carboxyl group onto the polyester resin can also be used.

  A polyurethane having a carboxyl group can be easily produced by using a compound having a carboxyl group and a hydroxyl group such as dimethylolpropionic acid as a segment having a hydroxyl group.

  The polyurethane resin having a carboxyl group used in the present invention is obtained by reacting a polyisocyanate component with a polyol component containing a compound having a carboxyl group and a hydroxyl group such as dimethylolpropionic acid as a component for introducing a carboxyl group. Can be manufactured easily.

  As the polyol component, in addition to the diol component listed in the polyester production method, a trifunctional or higher functional polyol compound may be used as necessary.

  Examples of the polyisocyanate component include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, hexamethylene diisocyanate, phenylene diisocyanate, 1,5-naphthalene diisocyanate, metaxylylene diisocyanate, In addition to diisocyanate compounds such as isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated 4,4′-diphenylmethane diisocyanate, hydrogenated metaxylylene diisocyanate, crude 4,4′-diphenylmethane diisocyanate, and polyisocyanates such as polymethylene polyphenyl isocyanate Compounds can also be used.

  The polyurethane resin can be produced by a known method. For example, the addition reaction is preferably performed at room temperature or a temperature of about 40 to 100 ° C. in an inert organic solvent solution that does not react with isocyanate groups. At that time, a known catalyst such as dibutyltin dilaurate may be used.

  In the reaction system for producing the polyurethane resin, for example, a known chain extender such as diamine, polyamine, N-alkyl dialkanolamine such as N-methyldiethanolamine; dihydrazide compound can be used.

  In addition, as an organic polymer compound having an anionic group used in the present invention, a vinyl copolymer or polyester resin having a hydroxyl group, for example, maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, Resins having a carboxyl group obtained by a method of addition reaction of a polybasic anhydride such as trimellitic anhydride can also be used.

  The organic polymer compound having an anionic group used in the present invention is preferably an organic polymer compound having a carboxyl group having an acid value of 100 to 150 KOHmg / g. If the acid value exceeds 150 KOH mg / g, the hydrophilicity becomes too high, so that the water resistance of the coated material tends to be remarkably lowered. If the acid value is lower than 100 KOH mg / g, acid precipitation occurs. This is not preferable because the redispersibility in water after reconstitution tends to decrease.

  The weight average molecular weight of the vinyl copolymer having a carboxyl group used in the present invention is an aqueous pigment recording liquid that suppresses kogation in the heater portion and has excellent ejection stability (the viscosity of the aqueous pigment dispersion is low, The dispersion stability is also good, and when a water-based pigment recording liquid for an ink jet printer is prepared, it becomes easy to perform stable printing for a long period of time). In order to obtain a weight average molecular weight (Mw) of 6 in terms of styrene It is preferably in the range of 000 to 12,000, and more preferably in the range of 7,000 to 9,000. If the weight average molecular weight is 6,000 or less, the dispersion stability of the aqueous pigment dispersion itself is lowered. Conversely, if it is 12,000 or more, not only the viscosity of the aqueous pigment dispersion is increased, but also the dispersibility. There is a tendency to decrease. Further, the kogation on the heater portion becomes severe, which causes non-ejection of ink droplets from the nozzle tip of the thermal ink jet printer, which is not preferable.

  For this reason, the weight average molecular weight can be controlled by the addition amount of the polymerization initiator, the reaction concentration, etc., but a chain transfer catalyst is effective in consideration of economy. Moreover, if it is the same monomer composition and the same molecular weight, it is preferable to use a chain transfer catalyst because it is superior in kogation resistance.

  Examples of the chain transfer catalyst include thiols such as n-dodecyl mercaptan, n-octyl mercaptan, thioglycerol, octyl 3-mercaptopropionate, 2,4-diphenyl-4-methyl-1-pentene (α-styrene dimer). ) And the like. The amount added is preferably in the range of about 1 to 10% in terms of mass, and more preferably in the range of about 1 to 5%.

  Since the polyester resin used in the present invention is mostly a branched type, unlike the case of a linear vinyl copolymer, the weight average molecular weight is large even when the number average molecular weight is small. It has sufficient toughness as a coating film. Accordingly, the polyester resin preferably has a number average molecular weight in the range of 1,000 to 20,000, and a weight average molecular weight in the range of 5,000 to 100,000.

  Next, the manufacturing method of the present invention will be described in order according to the steps. In the present invention, a suspension containing a neutralized organic polymer compound having an anionic group and a copper phthalocyanine pigment has a uniform particle size distribution in which the copper phthalocyanine pigment has a narrow particle size distribution with a predetermined particle size. It passes through the above-mentioned dispersing device until it is dispersed, and is mixed well to obtain a pigment dispersion.

  In addition to the organic polymer compound and the copper phthalocyanine pigment, this suspension usually contains a liquid medium as a medium to be dispersed. As this liquid medium, an organic solvent or an aqueous medium is used. In the present invention, as the main solvent constituting the liquid medium, an organic solvent medium is referred to as an organic solvent medium, and an aqueous medium is referred to as water.

  As the step of mixing and dispersing the organic polymer compound having an anionic group neutralized with a basic compound and a copper phthalocyanine pigment, the following two methods may be mentioned.

  (1) In an organic solvent medium, an organic polymer compound having an anionic group neutralized with a basic compound and a copper phthalocyanine pigment are mixed to form a suspension, and after the copper phthalocyanine pigment is dispersed, Disperse in the medium. (2) In an aqueous medium, an organic polymer compound having an anionic group neutralized with a basic compound and a copper phthalocyanine pigment are mixed and dispersed.

  In dispersion in an organic solvent, which is a first method applicable to the step of mixing and dispersing an organic polymer compound having an anionic group neutralized with a basic compound and a copper phthalocyanine pigment, A suspension containing an organic solvent solution of an organic polymer compound having an anionic group neutralized with an organic compound and a copper phthalocyanine pigment is obtained, and this is used as a rotor and separator in a short cylindrical pulverizing section as described above. The copper phthalocyanine pigment is finely dispersed using a dispersion medium stirring type dispersion apparatus having

  The organic solvent used at this time generally has good solubility in an organic polymer compound having an anionic group, and there is no problem in the synthesis of the organic polymer compound having an anionic group, the vapor pressure is higher than water, Those that are easy to remove the solvent and those that are miscible with water are preferred.

  As such a solvent, for example, acetone, methyl ethyl ketone, methanol, ethanol, n-propanol, isopropanol, ethyl acetate, tetrahydrofuran and the like are particularly preferable. Although its miscibility with water is low, methyl isopropyl ketone, methyl-n-propyl ketone, isopropyl acetate, n-propyl acetate, methylene chloride and the like can also be used.

  In order to further disperse a pigment dispersion composed of an organic polymer compound having an anionic group neutralized with a basic compound and a copper phthalocyanine pigment, dispersed in an organic solvent medium, in an aqueous medium, the following: Various methods are suitable.

  When dispersed in an aqueous medium, it is carried out using normal low-shear stirring, high-shear stirring with a homogenizer, or ultrasonic waves. In addition, for the purpose of assisting dispersion in an aqueous medium, a surfactant, a protective colloid, and the like can be used in combination as long as the water resistance of the coating film is not significantly reduced.

  Examples of the basic compound for neutralizing the organic polymer compound having an anionic group include inorganic bases and organic amines. Examples of the inorganic base include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like. Examples of the organic amine include ammonia, ethanolamine, diethanolamine, triethanolamine, tributylamine, N-methylethanolamine, dimethylethanolamine, diisopropanolamine, N-ethyldiethanolamine, 2-amino-2-methylpropanol, 2- Examples include ethyl-2-amino-1,3-propanediol, 2- (aminoethyl) ethanolamine, tris (hydroxymethyl) aminomethane, piperidine, morpholine and the like.

  Next, dispersion in an aqueous medium, which is a second method applicable to the step of mixing and dispersing an organic polymer compound having an anionic group neutralized with a basic compound and a copper phthalocyanine pigment, First, the anionic group of the organic polymer compound having an anionic group is neutralized with the basic compound described above, mixed with a copper phthalocyanine pigment in an aqueous medium, and dispersed.

  At this time, the organic polymer compound having an anionic group dissolved or dispersed in water may contain an organic solvent, or may be a medium substantially containing only water after removing the solvent. As the copper phthalocyanine pigment, any of a powder pigment, an aqueous slurry, and a press cake can be used. The dispersion method, the organic solvent, and the basic compound can be the same method and the same material as in the dispersion in an organic solvent medium.

  Regardless of whether it is an organic solvent-based or aqueous-based dispersion, use a pigment dispersant or wetting agent within the range that does not reduce the water resistance of the coating film for the purpose of assisting the dispersion of the copper phthalocyanine pigment. You can also.

  As the above method of mixing and dispersing an organic polymer compound having an anionic group neutralized with a basic compound and a copper phthalocyanine pigment, the former method (1) is suitable.

  In the present invention, as described above, a pigment dispersion is obtained, and an ink jet printer in which a copper phthalocyanine pigment is coated with an organic polymer compound having a neutralized anionic group by using the pigment dispersion by a known and conventional method. An aqueous pigment dispersion can be obtained.

  The aqueous pigment dispersion of the present invention can be preferably produced by the method of the latter (2). More specifically, (a) an organic solvent containing an organic polymer compound having an anionic group obtained by neutralizing an anionic group with a basic compound to be water-soluble and an aqueous medium may be included. A copper phthalocyanine pigment is mixed in a liquid medium to form a suspension, and the suspension is further thoroughly mixed to finely disperse the copper phthalocyanine pigment, and then (b) an organic compound having an anionic group by adding an acidic compound. The copper phthalocyanine pigment is coated with an organic polymer compound having an anionic group by precipitating the polymer compound, and (c) an anionic group of the organic polymer compound having an anionic group is added by adding a basic compound. It is preferable to contain an aqueous dispersion which is neutralized and dispersed in an aqueous medium.

  From the suspension (a) in which the copper phthalocyanine pigment is not sufficiently uniformly dispersed in the liquid medium to be dispersed, a pigment dispersion in which the copper phthalocyanine pigment is uniformly finely dispersed in the liquid medium is obtained. In the obtaining step, a specific dispersing device as described above is used. In the present invention, precipitation of an organic polymer compound having an anionic group using an acidic compound may be referred to as acid precipitation.

  In addition, when the copper phthalocyanine pigment is dispersed, or after the dispersion and before acid precipitation, a substance other than the copper phthalocyanine pigment, for example, a dye, an antioxidant, a UV absorber, a curing catalyst for a coating binder Further, rust preventives, fragrances, chemicals and the like can be added.

  The ratio of the organic polymer compound having an anionic group and the copper phthalocyanine pigment is 10 to 200 parts by solid content of the organic polymer compound having an anionic group with respect to 100 parts of the copper phthalocyanine pigment in terms of mass. A range is preferred. When the amount of the organic polymer compound having an anionic group is less than 10 parts, it tends to be difficult to disperse the copper phthalocyanine pigment sufficiently finely, and when more than 200 parts, the copper in the dispersion When the ratio of the phthalocyanine pigment is reduced and the aqueous pigment dispersion is used as a coating agent or the like, there is a tendency that there is no allowance for blending design.

  Acid precipitation performed for the purpose of coating a copper phthalocyanine pigment finely dispersed in an aqueous medium with an organic polymer compound having an anionic group is performed by adding an acidic compound to make the pH neutral or acidic. An organic polymer compound having an anionic group neutralized by an ionic compound is deposited.

  Examples of acidic compounds that can be used include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid; organic acids such as formic acid, acetic acid, and propionic acid. Larger hydrochloric acid and sulfuric acid are preferred. The pH during acid precipitation is preferably in the range of 3 to 6, but some pigments are decomposed by acid. In the case of such pigments, acid precipitation in the range of pH 4 to 7 is preferred. Moreover, it is preferable to remove beforehand the organic solvent which exists in a system using methods, such as vacuum distillation and atmospheric distillation, before performing acid precipitation.

  After acid precipitation, if necessary, filtration and washing with water are performed to obtain a water-containing cake of a copper phthalocyanine pigment coated with an organic polymer compound having an anionic group. As a filtration method, known methods such as suction filtration, pressure filtration, and centrifugation can be employed.

  This water-containing cake is kept in a fine state without agglomerating the copper phthalocyanine pigment particles by re-neutralizing the anionic group with a basic compound without drying, without drying. And redispersed in an aqueous medium. As the basic compound for redispersion, the same compound as the basic compound used for neutralizing the organic polymer compound having an anionic group can be used.

  The aqueous pigment dispersion obtained by coating a copper phthalocyanine pigment with an organic polymer compound having a carboxyl group neutralized with a base thus obtained has a volume average particle diameter in the range of 10 to 500 nm. preferable. When the volume average particle diameter is larger than 500 nm, it is not preferable because it tends to be difficult to obtain a coating film excellent in gloss, color developability and coloring power. Moreover, it is very difficult and unrealistic to obtain a volume average particle size smaller than 10 nm.

  The discharge method (piezo method, thermal method, etc.) of the ink jet printer is not particularly limited from the aqueous pigment dispersion obtained from the production method of the present invention, and the aqueous pigment recording prepared using the aqueous pigment dispersion The liquid can be used in any system. As a method for forming a recorded image using the aqueous pigment recording liquid prepared here, it is possible to print on various papers, sheets, films, fibers, metals and the like using an on-demand ink jet printer.

  The inkjet printer is not particularly limited as described above, and examples thereof include a piezo method using a piezoelectric element in the printer head and a heater, and a thermal method in which discharge is performed with pressure due to foaming due to heat generation. . In particular, in the present invention, it is preferable to adopt a thermal method. Further, it is possible to fix the image by applying energy such as heat or ultraviolet rays after printing.

  The aqueous pigment dispersion of the present invention thus obtained has a high discharge stability of the aqueous pigment recording liquid on a recording medium in use of an aqueous pigment recording liquid for an ink jet printer, and is excellent in various durability of printed matter. A film can also be obtained.

  When preparing the aqueous pigment recording liquid for ink jet printers of the present invention, the aqueous pigment dispersion is more preferably 2 to 5 so that the content of copper phthalocyanine pigment is in the range of 1 to 10% in terms of mass. It is preferable to mix and dilute water and / or a water-soluble organic solvent so as to be in the range of%.

  When the content of the copper phthalocyanine pigment is 1% or less, it is difficult to obtain a sufficient color density. On the other hand, when the content of the copper phthalocyanine pigment is 10% or more, the dispersion stability of the copper phthalocyanine pigment tends to decrease, which is not preferable. Here, the content of the copper phthalocyanine pigment refers to a single pigment particle of a copper phthalocyanine pigment not integrated with an organic polymer compound having a neutralized anionic group in an aqueous pigment dispersion, and a copper phthalocyanine pigment. Means the total content of the copper phthalocyanine pigment in the microcapsule type composite particles coated with an organic polymer compound having a neutralized anionic group.

  The water-soluble organic solvent used at this time can be appropriately selected from the above-mentioned organic solvents used for preparing the aqueous pigment dispersion. By coexisting with the water-soluble organic solvent, it is possible to easily control the ink permeability, viscoelasticity, surface tension, pigment dispersion stability, and the like particularly required for the aqueous pigment recording liquid for inkjet printers.

  Here, the order of mixing water and / or the water-soluble organic solvent is not particularly limited. For example, water and the water-soluble organic solvent can be mixed in the aqueous pigment dispersion. Water and the water-soluble organic solvent can be added separately to the aqueous pigment dispersion, but it is preferable to dilute them as a liquid medium in which these are mixed in advance in that the problem of solvent shock can be solved. As a specific mixing order, it is preferable to first mix water and a water-soluble organic solvent in advance, and add this to the aqueous pigment dispersion to make the composition of the aqueous pigment recording liquid.

  In the preparation of the aqueous pigment dispersion for ink jet printers and the aqueous pigment recording liquid of the present invention, water-soluble polyethers, water-soluble polyesters, water-soluble poly (meth) acrylates are used as various additives as long as they do not impair productivity. A water-soluble polymer compound such as a dye, a rheology modifier such as a dye or various minerals, a sugar such as starch or cellulose, a bactericide, or the like can be added as necessary. When these additives are added at the time of preparing the aqueous pigment dispersion, it is preferable in that the amount added can be suppressed to a smaller amount than when they are added at the time of preparing the aqueous pigment recording liquid. The addition amount of these additives is the addition amount with respect to the aqueous pigment dispersion, and is preferably in the range of 10% or less in terms of mass.

  Further, when preparing the aqueous pigment recording liquid, the rheology adjusting agent, wetting agent, preservative and the like as described above are used for the purpose of controlling the permeability to paper, maintaining the pigment dispersibility, and increasing the gloss of the image. Additives can also be added to this.

  Hereinafter, the present invention will be described in detail with reference to synthesis examples, examples and comparative examples. The present invention is not limited to these examples. Unless otherwise specified, both “part” and “%” are based on mass.

(Synthesis Example 1)
Synthesis of styrene-acrylic acid copolymer Automatic polymerization reactor (polymerization tester DSL-2AS type, Sakai Sangyo Co., Ltd.) having a reactor equipped with a stirring device, a dropping device, a temperature sensor, and a reflux device having a nitrogen introduction device at the top 1,200 parts of methyl ethyl ketone was charged into a reaction vessel manufactured by Co., Ltd., and the inside of the reaction vessel was purged with nitrogen while stirring. After raising the temperature in the reaction vessel to 80 ° C. while maintaining a nitrogen atmosphere, 75 parts of 2-hydroxyethyl methacrylate, 169 parts of methacrylic acid, 500 parts of styrene, 226 parts of benzyl methacrylate, and 30 parts of glycidyl methacrylate from the dropping device. , 40 parts of Bremer TGL (manufactured by NOF Corporation) and 80 parts of (perbutyl (registered trademark) O) [active ingredient t-butyl peroxy-2-ethylhexanoate, manufactured by NOF Corporation] over 4 hours It was dripped. After completion of the dropping, the reaction was further continued at the same temperature for 10 hours to obtain an organic polymer compound solution (A) having an acid value of 110 KOH mg / g, Tg of 89 ° C., a weight average molecular weight of 8,000, and a resin content of 45.4%. .

(Synthesis Example 2)
The same procedure as in Synthesis Example 1 was performed except that 230 parts of methacrylic acid and 165 parts of benzyl methacrylate were used in Synthesis Example 1, and the acid value was 150 KOH mg / g, Tg 93 ° C., weight average molecular weight 7,700, resin content 46 A 4% organic polymer compound solution (B) was obtained.

(1) Pigment Dispersing Step 33 parts of 25% potassium hydroxide and 715 parts of ion-exchanged water were added, and 164 parts of the organic polymer compound solution (A) obtained in Synthesis Example 1 and 35 of methyl ethyl ketone were added. Part was added and stirred to neutralize 100% of the carboxyl groups in the organic polymer compound, and the organic polymer compound was dissolved in water. Next, 248 parts of FASTOGEN BLUE TGR (copper phthalocyanine pigment manufactured by Dainippon Ink & Chemicals, Inc., CI Pigment Blue 15: 3) was slowly added with stirring, and the mixture was further stirred for 30 minutes, followed by copper phthalocyanine. A pigment suspension was obtained.

  A suspension of the obtained copper phthalocyanine pigment is dispersed in a dispersion medium stirring type dispersion apparatus (made by Mitsui Mining Co., Ltd.) having an external fixed container and an internal stirring apparatus (rotor) as shown in FIG. SC Mill 100/32 type, vessel capacity 3L, motor capacity 3.7 kW) is charged with 440 parts of a dispersion medium 0.3 mmφ zirconia beads (YTZ beads manufactured by Nikkato Co., Ltd.), and the suspension A holding container and a circulation pump are further provided, and the liquid discharge port, the container holding the suspension, the circulation pump, and the liquid supply port are connected in this order, and the pigment has a predetermined particle diameter in the holding container. The suspension is circulated so as to be within the range of the residence time until the pigment dispersion becomes, and an organic polymer compound having a carboxyl group neutralized with a base and a copper phthalocyanine pigment are used. It was obtained comprising an aqueous dispersion (pigment dispersion). The dispersion conditions at this time were a total stirring power of 5.0 kwh in the dispersion apparatus, and the applied energy efficiency was 20 kwh / kg.

(2) Solvent distillation step After adding water to an aqueous dispersion (pigment dispersion) consisting of an organic polymer compound having a carboxyl group neutralized with a base and a copper phthalocyanine pigment and diluting it twice, by atmospheric distillation Methyl ethyl ketone was distilled.

(3) Acid precipitation step While stirring the aqueous dispersion after solvent distillation with a disper, 1N hydrochloric acid is added to adjust the pH of the aqueous dispersion to 3 to 5, the organic polymer compound is precipitated, and the carboxyl group is removed. A copper phthalocyanine pigment was coated with the organic polymer compound.

(4) Filtration and washing step The copper phthalocyanine pigment slurry coated with the organic polymer compound having a carboxyl group was suction filtered and washed with water to obtain a water-containing cake.

(5) Neutralization and redispersion step in aqueous medium While stirring with a disper, 25% potassium hydroxide was added to the water-containing cake to adjust the pH of the dispersion to 8.5 to 9.5. Further, after stirring for 1 hour, water was added to adjust the non-volatile content to 20%, and the copper phthalocyanine pigment was coated with an organic polymer compound having a carboxyl group neutralized with a base. An aqueous pigment dispersion (A-1) for an inkjet printer was obtained.

(1) Pigment dispersion step 45 parts of 25% potassium hydroxide and 703 parts of ion-exchanged water were added, and the resulting mixture was uniformly mixed with 160 parts of the organic polymer compound solution (B) obtained in Synthesis Example 2 and methyl ethyl ketone 38. Part was added and stirred to neutralize 100% of the carboxyl groups in the organic polymer compound, and the organic polymer compound was dissolved in water. Next, 248 parts of FASTOGEN BLUE TGR (copper phthalocyanine pigment manufactured by Dainippon Ink & Chemicals, Inc., CI Pigment Blue 15: 3) was slowly added with stirring, and the mixture was further stirred for 30 minutes, followed by copper phthalocyanine. A pigment suspension was obtained. Thereafter, the same operation as in Example 1 was carried out (dispersion conditions were a total stirring power of 5.0 kwh in the dispersion apparatus and an applied energy efficiency of 20 kwh / kg).

  Subsequently, through the same steps as in Example 1, (2) solvent distillation step, (3) acid precipitation step, (4) filtration and water washing step, and (5) neutralization and redispersion step in an aqueous medium, the non-volatile content was 20 An aqueous pigment dispersion (B-1) for inkjet printers obtained by coating a copper phthalocyanine pigment with an organic polymer compound having a carboxyl group neutralized with% base was obtained.

(Comparative Example 1)
In the Example 1 (1) pigment dispersion step, the dispersion conditions were changed from 5.0 to 10 kwh in the total stirring power in the dispersion apparatus and 20 to 40 kwh / kg of applied energy efficiency at this time, respectively. 1. An aqueous pigment dispersion for an ink jet printer (A-2), which is the same as No. 1 and is coated with a copper phthalocyanine pigment with an organic polymer compound having a carboxyl group neutralized with a base having a nonvolatile content of 20% Got.

(Comparative Example 2)
In the Example 2 (1) pigment dispersion step, the dispersion conditions were changed from 5.0 to 10 kwh in the total stirring power in the dispersing device and 20 to 40 kwh / kg of applied energy efficiency at this time, respectively. A water-based pigment dispersion for ink jet printers (B-2), wherein the same operation as in No. 2 is performed, and a copper phthalocyanine pigment is coated with an organic polymer compound having a carboxyl group neutralized with a base having a nonvolatile content of 20% Got.

(Preparation of aqueous pigment recording liquid)
With reference to Example 2 described in JP-A-6-122846, 26 parts of an aqueous pigment dispersion for an ink jet printer obtained in each Example and Comparative Example, 8 parts of glycerin, 5 parts of ethylene glycol, 5 parts of ethanol , Emargen (registered trademark) 120 (non-ionic surfactant manufactured by Kao Corporation) and 55.95 parts of ion-exchanged water are mixed, and an organic polymer compound having a carboxyl group neutralized with a base An aqueous pigment recording liquid for an ink jet printer, which was coated with a copper phthalocyanine pigment, was prepared.

(Ejection stability evaluation test of aqueous pigment recording liquid)
The water-based pigment recording liquid prepared as described above is used as a cartridge of a thermal ink jet printer BJ F300 type (made by Canon Inc.) equipped with a bubble jet (registered trademark) recording head (BC-30E, made by Canon Inc.). The character pattern was continuously printed on A4 size plain paper.
The discharge stability is judged to be better as the number of printed sheets of continuous printed matter is larger (the number of sheets that can be printed without discharge), and in the present invention, it is ranked in two stages of ○ and ×. I did it. That is, ◯ indicates that the number of printed sheets is 550 or more, and x indicates that the number of printed sheets is 550 or less. The results are shown in Table 1.

                                  Table 1

  As is apparent from the results in Table 1, the aqueous pigment recording liquid prepared from the aqueous pigment dispersion for inkjet printers obtained by the production method of the present invention is excellent in ejection stability and obtains a sufficiently satisfactory cyan color image. I was able to. On the other hand, the aqueous pigment recording liquid prepared from the aqueous pigment dispersion produced under the conventional conditions of applied energy efficiency was insufficiently discharged, and a satisfactory cyan image could not be obtained.

From the above, the present invention is a condition that the copper phthalocyanine pigment is applied to a dispersion medium agitation type dispersion device having a rotor and a separator in the cylindrical pulverization unit, and the applied energy efficiency of the dispersion device is in the range of 15 to 25 kwh / kg. A pigment dispersion is prepared by finely dispersing under the above, and an aqueous pigment dispersion for an ink jet printer in which the pigment is coated with the organic polymer compound having a neutralized anionic group obtained here is produced. Therefore, the aqueous pigment recording liquid prepared from the aqueous pigment dispersion has a higher ejection efficiency than the aqueous pigment recording liquid prepared under the conventional conditions in terms of ejection stability. It turned out to be excellent.
Therefore, the method for producing the aqueous pigment dispersion of the present invention and the aqueous pigment recording liquid prepared from the aqueous pigment dispersion obtained by the production method are optimal for inkjet printer applications.

It is sectional drawing of an example of the dispersion apparatus used by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 External fixed container 2 Cylindrical rotor 3 Rotor rotating shaft 4 Supply port 5 Slit 6 Liquid chamber 7 Dispersion media 8 Separator 9 Discharge port

Claims (7)

  A method for producing an aqueous pigment dispersion for an inkjet printer, wherein a copper phthalocyanine pigment is coated with a neutralized organic polymer compound having an anionic group, the organic polymer compound having a neutralized anionic group And a suspension containing a copper phthalocyanine pigment, and a fine dispersion of the copper phthalocyanine pigment to obtain a pigment dispersion, a separator having a suspension supply port and a discharge port is used as a dispersion device. The inner fixed wall includes a cylindrical outer fixed container (I) and a cylindrical rotor (II) that is provided in the inside through a predetermined gap and is rotatable about the rotation axis. The rotor (II) is a cylinder. A rotor having a hollow liquid chamber inside and capable of supplying a suspension toward the liquid chamber and having a slit facing the supply port and a plurality of liquid discharge holes on a cylindrical side wall communicating with the outside of the liquid chamber II), and a separator having a plurality of holes having a predetermined diameter smaller than that of the dispersion medium is provided on the cylindrical inner wall, the outer fixed container (I) being opposed to the circumferential outer wall surface of the rotor via a predetermined gap. The outer fixed container (I) is made of a dispersion device filled with a dispersion medium in the gap between the rotor and the separator, and the rotor (II) is rotated from the supply port of the container (I) while rotating the rotor (II). Suspension is supplied to the liquid chamber toward the slit, the suspension is discharged from the discharge hole by centrifugal force, and the suspension that has passed through the separator via the dispersion medium is discharged from the discharge port of the container (I). When taking out, the suspension is supplied so that the applied energy efficiency in the dispersing device is 15 to 25 kwh per 1 kg of the pigment, and the copper phthalocyanine pigment is finely dispersed to obtain a pigment dispersion. Method of manufacturing an inkjet printer aqueous pigment dispersion that.   The method for producing an aqueous pigment dispersion for an ink jet printer according to claim 1, wherein the applied energy efficiency is 17 to 22 kwh per 1 kg of the pigment.   Copper phthalocyanine pigments are C.I. I. Pigment Blue 15: 3 or C.I. I. It is Pigment Blue 15: 4. The manufacturing method of the aqueous pigment dispersion for inkjet printers of Claim 1 or 2.   4. The aqueous pigment dispersion for an inkjet printer according to claim 1, wherein the organic polymer compound having an anionic group is an organic polymer compound having a carboxyl group with an acid value of 100 to 150 KOH mg / g. 5. Production method.   An organic polymer compound having an anionic group neutralized with a basic compound and water-soluble, an aqueous medium, and a copper phthalocyanine pigment are mixed to form a suspension, and the copper phthalocyanine pigment is added to the suspension liquid medium. As a dispersion device, an inner wall having a separator and having a separator and having a separator is provided in a cylindrical external fixed container (I) with a predetermined gap therebetween. The cylindrical rotor (II) that can rotate about the rotation axis, and the rotor (II) has a hollow liquid chamber inside the cylinder and can supply a suspension toward the liquid chamber. A rotor (II) having a slit facing the opening and a plurality of liquid discharge holes on a cylindrical side wall communicating with the outside of the liquid chamber, and the external fixed container (I) has a predetermined gap from the circumferential outer wall surface of the rotor. Opposite, distributed media A separator having a plurality of small holes having a predetermined diameter is an outer fixed container (I) provided on a cylindrical inner wall, and a rotor using a dispersing device in which a dispersion medium is filled in a gap between the rotor and the separator. While rotating (II), the suspension is supplied to the liquid chamber from the supply port of the container (I) toward the slit of the rotor, and the suspension is discharged from the discharge hole by centrifugal force. The copper phthalocyanine pigment is made anionic by adding an acidic compound and precipitating an organic polymer compound having an anionic group to the pigment dispersion liquid taken out from the discharge port of the container (I). Coating with an organic polymer compound having a group, and then adding a basic compound to neutralize the anionic group of the organic polymer compound having an anionic group and dispersing in an aqueous medium to disperse the aqueous pigment And then, the production method of the ink jet printer aqueous pigment dispersion as claimed in any one of claims 1 to 4, to prepare an aqueous pigment recording liquid by using the same.   The method for producing an aqueous pigment dispersion for an ink jet printer according to any one of claims 1 to 5, wherein a discharge method of the ink jet printer has a heater, and employs a thermal method in which the ink is discharged by pressure generated by foaming due to heat generation.   The aqueous pigment for an ink jet printer prepared from the aqueous pigment dispersion obtained by the production method according to any one of claims 1 to 6, wherein the content of the copper phthalocyanine pigment is in the range of 1 to 10% in terms of mass. Recording liquid.

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