JP2008201914A - Dispersion of organic pigment particulate mixture, its solid matter and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dispersion of mixed nanometer-sized organic pigment particulates, which has a narrow particle size distribution and shows a high light fastness, its solid matter and its production method, to provide the dispersion of the mixed organic pigment particulates, which has the excellent characteristics and can be suitably used for producing a color filter or an inkjet ink, and its solid matter, and to provide a production method for efficiently obtaining the dispersion. <P>SOLUTION: The dispersion of the mixed organic pigment particulates comprises at least two organic pigments as particle components, provided that the mixed particulates are nanometer-sized built-up pigment particulates which are produced through precipitation induced by contacting an aqueous medium with a mixed organic pigment solution wherein the at least two organic pigments are dissolved. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an organic pigment mixed fine particle dispersion, a solid thereof, and a production method thereof. More specifically, the present invention relates to an organic pigment mixed fine particle dispersion having a nanometer size and high light resistance, a solid material thereof, and a production method thereof.

  Pigments show vivid colors and high tinting strength and are widely used in many fields. For example, paints, printing inks, electrophotographic toners, inkjet inks, color filters, and the like can be used. Among them, high performance is required, and ink jet inks and color filters are particularly important in practical use.

  Conventional dyes have been used as coloring materials for ink-jet inks, but there are drawbacks in terms of water resistance and light resistance, and pigments have come to be used to improve them. An image obtained with a pigment ink has a remarkable advantage in that it is excellent in light resistance and water resistance as compared with that obtained with a dye-based ink. Further, in the color filter for a CCD sensor, it is desired to reduce the thickness of the color filter especially with the increase in the number of pixels of a digital camera in recent years. In order to achieve this, it is required that the pigment particles be obtained by making the particles fine and controlling the particle size. Specifically, it is necessary that the pigment fine particles have a nanometer size and be close to monodispersion.

  A breakdown method (pulverization method) is generally employed as a method for forming pigment particles. This is a conventional method using a flask or the like. Thus, for example, there is an example in which a mixed crystal of quinacridone quinone pigment is prepared and a weather-resistant automotive paint is prepared (see Patent Document 1). However, this conventional method requires a great deal of time and energy for particle miniaturization. In addition, applicable substances are limited.

  On the other hand, research on a build-up method in which pigment particles are grown in a gas phase or in a liquid phase is underway (see Non-Patent Document 1). Specifically, there has been disclosed a method for efficiently preparing an organic pigment dispersion by a microchemical process (see Patent Documents 2 and 3). However, when the particle size of the organic pigment is lowered, the light fastness is lowered (see Non-Patent Document 2). In particular, pigment fine particles refined to a nanometer size by the build-up method have a specific problem that the above-mentioned decrease in light fastness becomes remarkable.

JP 62-62867 A JP 2005-307154 A JP 2006-342304 A "Chemical Course of 4th Edition", Volume 12 of the Chemical Society of Japan, Year, 411-488, Maruzen Co., Ltd. "Organic Pigment Handbook" Color Office, 45 pages

The object of the present invention is to solve the problems peculiar to the above build-up method.
That is, an object of the present invention is to provide an organic pigment mixed fine particle dispersion having a nanometer size, a narrow particle size distribution, and high light resistance, a solid material thereof, and a production method thereof. In addition, an organic pigment fine particle dispersion having the above-mentioned excellent characteristics and suitable for use in color filters and inkjet inks, and a production method for efficiently obtaining the dispersion are provided for the purpose of providing the solid. With the goal.

The above problems have been achieved by the following means.
(1) Dispersion of organic pigment mixed fine particles having two or more kinds of organic pigments as particle components, wherein the mixed fine particles contact the mixed organic pigment solution in which the two or more kinds of organic pigments are dissolved and an aqueous medium. An organic pigment mixed fine particle dispersion comprising nanometer-sized build-up pigment fine particles precipitated and produced.
(2) As the two or more kinds of organic pigments, 80% by mass or more of the main component organic pigment is contained in the total pigment, and has a maximum absorption wavelength on the longer wavelength side of 10 to 100 nm than the maximum absorption wavelength indicated by the main component organic pigment. The organic pigment mixed fine particle dispersion according to (1), wherein at least one subcomponent organic pigment is contained.
(3) The organic pigment mixed fine particle dispersion described in (1) or (2), wherein the mixed fine particles have a volume average particle size (Mv) of 50 nm or less.
(4) The ratio (Mv / Mn) between the volume average particle size (Mv) and the number average particle size (Mn) of the mixed fine particles is set to 1.8 or less. (1) to (3) The organic pigment mixed fine particle dispersion according to any one of the above.
(5) A solid matter of organic pigment mixed fine particles obtained by drying the dispersion according to any one of (1) to (4).
(6) An organic pigment characterized in that a mixed organic pigment solution in which two or more organic pigments are dissolved is brought into contact with an aqueous medium to precipitate and produce mixed fine particles having the two or more organic pigments as particle components. Manufacturing method of mixed fine particle dispersion.
(7) The method for producing an organic pigment mixed fine particle dispersion according to (6), wherein the mixed organic pigment solution is a solution in which the two or more organic pigments are dissolved with an alkali or an acid.
(8) As the two or more kinds of organic pigments, a main component organic pigment is contained in an amount of 80% by mass or more in all pigments, and a secondary absorption having a maximum absorption wavelength on the long wavelength side of 10 to 100 nm from the maximum absorption wavelength indicated by the main component organic pigment The method for producing an organic pigment mixed fine particle dispersion according to (6) or (7), wherein one or more component organic pigments are contained.
(9) The method for producing an organic pigment mixed fine particle dispersion according to any one of (6) to (8), wherein the mixed fine particles have a volume average particle size (Mv) of 50 nm or less.
(10) The ratio (Mv / Mn) between the volume average particle size (Mv) and the number average particle size (Mn) of the mixed fine particles is set to 1.8 or less. (6) to (9) The manufacturing method of the organic pigment mixed fine particle dispersion of any one of Claims 1.
(11) The mixed organic pigment fine particle dispersion according to any one of (6) to (10), wherein the mixed organic pigment solution and an aqueous medium are brought into contact with each other in a flow path of a microreactor. Method.
(12) The method for producing the organic pigment mixed fine particle dispersion according to (11), wherein an equivalent diameter of the flow path of the microreactor is 1 mm or less.
(13) The method for producing an organic pigment mixed fine particle dispersion according to any one of (6) to (12), wherein the mixed organic pigment solution and the aqueous medium are contacted in a laminar flow process.

The organic pigment mixed fine particles contained in the dispersion of the present invention have a nanometer size, a sharp peak of particle size distribution, good dispersion stability, and high light resistance.
Moreover, the organic pigment mixed fine particle dispersion of the present invention having the above excellent characteristics can be suitably used for a color filter and an inkjet ink.
Furthermore, according to the production method of the present invention, an organic pigment mixed fine particle dispersion having the above-described excellent characteristics can be produced efficiently.

The dispersion of the present invention contains nanometer-sized organic pigment fine particles formed by a build-up method. In the present invention, the build-up method refers to the formation of nanometer-sized fine particles that do not require atomization by separate pulverization or the like through a chemical reaction from an organic pigment or organic pigment precursor dissolved (molecularly dispersed) in a solvent. Say the method. In the present invention, fine particles formed by this build-up method are defined as build-up pigment fine particles.
The dispersion of the present invention contains fine pigment particles formed by bringing a mixed organic pigment solution obtained by dissolving (molecularly dispersing) two or more organic pigments into a good solvent and an aqueous medium into contact with each other. Especially, it is preferable to form by the coprecipitation method which raises the dispersion stability of microparticles | fine-particles by making a dispersing agent coexist in either or both of said mixed organic pigment solution and a poor solvent. In the coprecipitation method, when the dispersant is not present, the fine particle precipitation method is called a reprecipitation method and may be particularly distinguished. Regarding the coprecipitation method or the reprecipitation method, JP-A-2004-91560, JP-A-2003-026972 and the like can be referred to.

  The organic pigment used in the dispersion of the present invention is not particularly limited in terms of hue or structure. For example, perylene compound pigment, perinone compound pigment, quinacridone compound pigment, quinacridone quinone compound pigment, anthraquinone compound pigment, anthanthrone compound Pigment, benzimidazolone compound pigment, disazo condensation compound pigment, disazo compound pigment, azo compound pigment, indanthrone compound pigment, indanthrene compound pigment, quinophthalone compound pigment, quinoxalinedione compound pigment, metal complex azo compound pigment, phthalocyanine compound pigment Triarylcarbonium compound pigment, dioxazine compound pigment, aminoanthraquinone compound pigment, diketopyrrolopyrrole compound pigment, naphthol AS compound pigment, thioindigo compound pigment, Indoline compound pigments, isoindolinone compound pigments, pyranthrone compound pigments, isoviolanthrone compound pigment, or a mixture thereof.

  More specifically, for example, C.I. I. Pigment red 179, C.I. I. Pigment red 190, C.I. I. Pigment red 224, C.I. I. Perylene compound pigments such as C.I. Pigment Violet 29; I. Pigment orange 43, or C.I. I. Perinone compound pigments such as CI Pigment Red 194; I. Pigment violet 19, C.I. I. Pigment violet 42, C.I. I. Pigment red 122, C.I. I. Pigment red 192, C.I. I. Pigment red 202, C.I. I. Pigment red 207 or C.I. I. Pigment Red 209 quinacridone compound pigment, C.I. I. Pigment red 206, C.I. I. Pigment orange 48, or C.I. I. Quinacridonequinone compound pigments such as C.I. Pigment Orange 49; I. Anthraquinone compound pigments such as C.I. Pigment Yellow 147; I. Anthanthrone compound pigments such as C.I. Pigment Red 168; I. Pigment brown 25, C.I. I. Pigment violet 32, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 181, C.I. I. Pigment orange 36, C.I. I. Pigment orange 62, or C.I. I. Benzimidazolone compound pigments such as CI Pigment Red 185; I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 128), C.I. I. Pigment yellow 166, C.I. I. Pigment orange 34, C.I. I. Pigment orange 13, C.I. I. Pigment orange 31, C.I. I. Pigment red 144 (C.I. No. 20735), C.I. I. Pigment red 166, C.I. I. Pigment yellow 219, C.I. I. Pigment red 220, C.I. I. Pigment red 221, C.I. I. Pigment red 242, C.I. I. Pigment red 248, C.I. I. Pigment red 262, or C.I. I. Disazo condensation compound pigments such as C.I. Pigment Brown 23; I. Pigment yellow 13, C.I. I. Pigment yellow 83, or C.I. I. Disazo compound pigments such as C.I. Pigment Yellow 188; I. Pigment red 187, C.I. I. Pigment red 170, C.I. I. Pigment yellow 74, C.I. I. Pigment red 48, C.I. I. Pigment red 53, C.I. I. Pigment orange 64, or C.I. I. Azo compound pigments such as C.I. Pigment Red 247; I. Indanthrone compound pigments such as C.I. Pigment Blue 60; I. Indanthrene compound pigments such as C.I. Pigment Blue 60; I. Quinophthalone compound pigments such as C.I. Pigment Yellow 138; I. Quinoxalinedione compound pigments such as CI Pigment Yellow 213; I. Pigment yellow 129, or C.I. I. Pigment Yellow 150 and other metal complex azo compound pigments, C.I. I. Pigment green 7, C.I. I. Pigment green 36, C.I. I. Pigment green 37, C.I. I. Pigment blue 16, C.I. I. Pigment blue 75, or C.I. I. Phthalocyanine compound pigments such as C.I. Pigment Blue 15 (including 15: 1, 15: 6, etc.); I. Pigment blue 56 or C.I. I. Triarylcarbonium compound pigments such as C.I. Pigment Blue 61; I. Pigment violet 23, or C.I. I. Dioxazine compound pigments such as C.I. Pigment Violet 37; I. Aminoanthraquinone compound pigments such as C.I. Pigment Red 177; I. Pigment red 254, C.I. I. Pigment red 255, C.I. I. Pigment red 264, C.I. I. Pigment red 272, C.I. I. Pigment orange 71, or C.I. I. Diketopyrrolopyrrole compound pigments such as C.I. Pigment Orange 73; I. Pigment red 187, or C.I. I. Naphthol AS compound pigments such as C.I. Pigment Red 170; I. Thioindigo compound pigments such as C.I. Pigment Red 88; I. Pigment yellow 139, C.I. I. Pigment Orange 66 and other isoindoline compound pigments, C.I. I. Pigment yellow 109, C.I. I. Pigment yellow 110, or C.I. I. Pigment Orange 61 and other isoindolinone compound pigments, C.I. I. Pigment orange 40, or C.I. I. A pyranthrone compound pigment such as C.I. Pigment Red 216; I. And isoviolanthrone compound pigments such as CI Pigment Violet 31.

  The organic pigment mixed fine particles contained in the dispersion of the present invention have two or more organic pigment components. As the two or more kinds of organic pigment components, a main component organic pigment exhibiting a desired hue is contained in an amount of 80% by mass or more of the total pigment, and the long wavelength side is 10 to 100 nm from the maximum absorption wavelength (λmax) of the main component organic pigment. It is preferable to contain at least one subcomponent organic pigment having the maximum absorption wavelength. At this time, the main component organic pigment is more preferably 90% by mass or more, and particularly preferably 95% by mass or more. Regarding the maximum absorption wavelength, the maximum absorption wavelength of the subcomponent organic pigment is more preferably 10 to 200 nm longer than the maximum absorption wavelength of the main component organic pigment, and particularly preferably 10 to 100 nm longer wavelength. . Moreover, it is preferable to select and combine a secondary component organic pigment having light fastness when used alone higher than that when the main component organic pigment is used alone. The main component organic pigment and the subcomponent organic pigment are preferably a combination having the same pigment compound type, in other words, a similar compound skeleton, such as azo compound pigments and diketopyrrolopyrrole compound pigments. The absorption wavelength of the pigment in the present invention means an absorption wavelength in a state where particles are formed, that is, an absorption wavelength in a state where it is applied or kneaded to a medium, and is a solution state dissolved in a special medium such as alkali or acid. Is not the absorption wavelength.

Although the value of the maximum absorption wavelength (λmax) of the main component organic pigment is not particularly limited, it is practical to use a pigment having the maximum absorption wavelength in the visible light region in the coloring application. For example, the maximum absorption wavelength is 300 to 750 nm. It is preferable to use what has.
Specific examples of the combination of the main component organic pigment and the subcomponent organic pigment include the following combinations.
----------------------------------
Combination Main component organic pigment Subcomponent organic pigment ----------------------------------
1 Pigment Yellow 128 Pigment Orange 13
2 Pigment Yellow 128 Pigment Yellow 74
3 Pigment Yellow 128 Pigment Red 4
4 Pigment Violet 19 Pigment Red 122
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  When the organic pigment is uniformly dissolved with an alkali or an acid, it can be selected depending on which condition the target pigment is easily dissolved under which condition. Generally, an alkali is used in the case of a pigment having a group dissociable with an alkali in the molecule. On the other hand, when there is no group capable of dissociating with an alkali and there are many nitrogen atoms in the molecule to which protons can easily be added, an acid is used. For example, a quinacridone compound pigment, a diketopyrrolopyrrole compound pigment, and a disazo condensation compound pigment can be dissolved with an alkali, and a phthalocyanine compound pigment with an acid.

When dissolving with an alkali, inorganic bases such as sodium hydroxide, calcium hydroxide and barium hydroxide, organic bases such as trialkylamine, diazabicycloundecene (DBU) and metal alkoxides can be used. It is preferable to use a base.
The amount of the base to be used is not particularly limited, but in the case of an inorganic base, it is preferably 1.0 to 30 molar equivalents, more preferably 2.0 to 25 molar equivalents, and 3 to 20 relative to the pigment. A molar equivalent is particularly preferred. In the case of an organic base, it is preferably 1.0 to 100 molar equivalents, more preferably 5.0 to 100 molar equivalents, and particularly preferably 20 to 100 molar equivalents with respect to the pigment.

In the case of dissolving with an acid, an inorganic acid such as sulfuric acid, hydrochloric acid or phosphoric acid, or an organic acid such as acetic acid, trifluoroacetic acid, oxalic acid, methanesulfonic acid or trifluoromethanesulfonic acid can be used. It is preferable to be sulfuric acid, and sulfuric acid is particularly preferable.
The amount of the acid to be used is not particularly limited, but an excess amount is often used as compared with the base. Regardless of the case of an inorganic acid or an organic acid, the amount is preferably 3 to 500 molar equivalents, more preferably 10 to 500 molar equivalents, and particularly preferably 30 to 200 molar equivalents with respect to the pigment.

  In the present invention, the aqueous medium is water alone or a mixed solvent of water-soluble organic solvents. At this time, the addition of the organic solvent is not sufficient only with water to uniformly dissolve the pigment and the dispersant, and when only water is insufficient to obtain the viscosity necessary to flow through the flow path. It is preferable to use for such as. For example, in the case of alkali, the organic solvent is preferably an amide solvent or a sulfur-containing solvent, more preferably a sulfur-containing solvent, and particularly preferably dimethyl sulfoxide (DMSO). In the case of acidity, a carboxylic acid solvent, a sulfur solvent, or a sulfonic acid solvent is preferable, a sulfonic acid solvent is more preferable, and methanesulfonic acid is particularly preferable. In addition, you may dissolve an inorganic compound salt, the dispersing agent mentioned later, etc. in an aqueous medium as needed.

  At this time, the solution in which the organic pigment is uniformly dissolved and the aqueous medium are fed into a long flow path in the same longitudinal direction, and both liquids are contacted while passing through the flow path to precipitate organic pigment fine particles. It is preferable to make it. At this time, if the suspension is added, the particle size becomes large or the pigment fine particles have a wide particle distribution. In some cases, the flow path is blocked. In the present invention, “uniformly dissolved” is a solution in which turbidity is hardly observed when observed under visible light, and the liquid phase obtained through a microfilter of 1 μm or less, in other words, passed through a 1 μm filter. In this case, it is defined as a state in which an object to be filtered is not contained in the liquid phase.

  When the organic pigment mixed fine particles are precipitated by bringing the mixed organic pigment solution into contact with an aqueous medium, it is preferable to change the hydrogen ion index (pH). When the pigment fine particles are precipitated from the pigment dissolved in the alkali, the change of the hydrogen ion index (pH) is preferably lowered within the range of pH 16.0 to 5.0, and pH 16.0 to 10.0. It is more preferable to lower within the range. When the pigment fine particles are precipitated from the pigment dissolved in the acid, it is preferable to increase the pH within the range of about pH 1.5 to 9.0, more preferably within the range of pH 1.5 to 4.0. preferable. Although the width of the change depends on the value of the hydrogen ion exponent (pH) of the organic pigment solution, it should be sufficient to promote the precipitation of the organic pigment.

  The reaction temperature when precipitating the pigment mixed fine particles is preferably within a range where the solvent does not solidify or vaporize, specifically, preferably −20 to 90 ° C., more preferably 0 to 50 ° C. Preferably, it is 5-15 degreeC.

  When forming the pigment mixed fine particles, the velocity (flow rate) of the fluid flowing in the flow path is preferably 0.1 mL to 300 L / hr, more preferably 0.2 mL to 30 L / hr, and More preferably, it is 5 mL-15 L / hr, and it is especially preferable that it is 1.0 mL-6 L / hr.

  In the present invention, as described above, it is preferable to use organic pigment mixed fine particles which are precipitated by a coprecipitation method. A dispersant is added to the organic pigment solution and / or the aqueous medium, and both are brought into contact with each other. It is preferable that they are formed. The dispersant (1) has a function of adsorbing rapidly on the surface of the deposited pigment to form fine pigment particles, and (2) preventing these particles from aggregating again. As such a dispersant, an anionic, cationic, amphoteric, nonionic or pigmentary low molecular or high molecular dispersant can be used. These dispersants can be used alone or in combination. The dispersant used for dispersing the pigment is described in detail on pages 29 to 46 of “Pigment dispersion stabilization and surface treatment technology / evaluation” (Chemical Information Association, issued in December 2001).

  Examples of anionic dispersants (anionic surfactants) include N-acyl-N-alkyl taurine salts, fatty acid salts, alkyl sulfate esters, alkyl benzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinates, alkyl phosphorus Examples include acid ester salts, naphthalene sulfonic acid formalin condensate, polyoxyethylene alkyl sulfate ester salts, and the like. Of these, N-acyl-N-alkyltaurine salts are preferred. As the N-acyl-N-alkyltaurine salt, those described in JP-A-3-273067 are preferable. These anionic dispersants can be used singly or in combination of two or more.

  Cationic dispersants (cationic surfactants) include quaternary ammonium salts, alkoxylated polyamines, aliphatic amine polyglycol ethers, aliphatic amines, diamines and polyamines derived from aliphatic amines and fatty alcohols, fatty acids And imidazolines derived from these and salts of these cationic substances. These cationic dispersants can be used singly or in combination of two or more.

  The amphoteric dispersant is a dispersant having both an anion group part in the molecule of the anionic dispersant and a cationic group part in the molecule of the cationic dispersant.

  Nonionic dispersants (nonionic surfactants) include polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylamine, Examples thereof include glycerin fatty acid esters. Of these, polyoxyethylene alkylaryl ether is preferable. These nonionic dispersants can be used singly or in combination of two or more.

  The pigment dispersant is defined as a pigment dispersant which is derived from an organic pigment as a parent substance and is produced by chemically modifying the parent structure. For example, sugar-containing pigment dispersants, piperidyl-containing pigment dispersants, naphthalene or perylene-derived pigment dispersants, pigment dispersants having functional groups linked to the pigment parent structure through methylene groups, and polymer-modified pigment parents. Examples include a structure, a pigment dispersant having a sulfonic acid group, a pigment dispersant having a sulfonamide group, a pigment dispersant having an ether group, or a pigment dispersant having a carboxylic acid group, a carboxylic ester group, or a carboxamide group.

  Specifically, as the polymer dispersant, polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl methyl ether, polyethylene oxide, polyethylene glycol, polypropylene glycol, polyacrylamide, vinyl alcohol-vinyl acetate copolymer, polyvinyl alcohol-partial formalized product, Polyvinyl alcohol-partially butyralized product, vinyl pyrrolidone-vinyl acetate copolymer, polyethylene oxide / propylene oxide block copolymer, polyacrylate, polyvinyl sulfate, poly (4-vinylpyridine) salt, polyamide, polyallylamine salt, Condensed naphthalene sulfonate, styrene-acrylate copolymer, styrene-methacrylate copolymer, acrylate ester-acrylate copolymer, acrylate ester Methacrylate copolymer, methacrylate ester-acrylate copolymer, methacrylate ester-methacrylate copolymer, styrene-itaconate copolymer, itaconate-itaconate copolymer, vinyl Examples thereof include naphthalene-acrylate copolymer, vinyl naphthalene-methacrylate copolymer, vinyl naphthalene-itaconate copolymer, cellulose derivative, starch derivative and the like. In addition, natural polymers such as alginate, gelatin, albumin, casein, gum arabic, tonganto gum and lignin sulfonate can also be used. Of these, polyvinylpyrrolidone is preferable. These polymer dispersants can be used singly or in combination of two or more.

  A preferred embodiment includes an embodiment in which an anionic dispersant is contained in an aqueous medium, and a nonionic dispersant and / or a polymer dispersant is contained in an organic pigment solution.

  The amount of the dispersing agent is preferably in the range of 0.1 to 1000 parts by mass with respect to 100 parts by mass of the pigment in order to further improve the uniform dispersibility and storage stability of the pigment, The range is more preferably in the range of parts by mass, and particularly preferably in the range of 10 to 250 parts by mass. If this amount is too small, the dispersion stability of the organic pigment fine particles may not be improved.

The particle diameter of the organic pigment mixed fine particles contained in the dispersion of the present invention (in the present invention, the particle diameter means the diameter of the particles) and monodispersibility are not particularly limited, but the average particle diameter is nanometer size (1 μm). Less).
The organic pigment mixed fine particles contained in the dispersion of the present invention preferably have a volume average particle size (Mv) measured by a dynamic light scattering method in the dispersion of 80 nm or less, and preferably 5 to 50 nm. More preferred. For monodispersity, the value (Mv / Mn) obtained by dividing the volume average particle size (Mv), which is an index thereof, by the number average particle size (Mn) is preferably 1.8 or less. More preferably, it is 1.5 or less.
In the present invention, the “dispersion” refers to a composition in which predetermined fine particles are dispersed in a medium, and the form thereof is not particularly limited, and is a liquid composition (dispersion), a paste-like composition, and a solid. It is used to mean including a composition in the form of a tube.
In the dispersion of the present invention, the content of the organic pigment mixed fine particles is not particularly limited, but is preferably 1 to 15% by mass, and more preferably 2 to 8% by mass.

  In the present invention, a gas such as air or oxygen may coexist at the time of pigment fine particle deposition. For example, they can be used as an oxidizing agent. The mode of coexistence is not particularly limited, and the gas may be dissolved in the organic pigment solution and / or the aqueous medium in advance, or the above gas may be introduced and contacted separately from the both liquids.

  The organic pigment mixed fine particles to be contained in the dispersion of the present invention are preferably formed in a microreactor flow path. As a preferred embodiment thereof, (i) the equivalent diameter of the microreactor flow path is 1 mm or less ( (Ii) An embodiment in which a laminar flow is formed in the flow channel of the microreactor. Particle formation under laminar flow stabilizes the process from nucleation to nucleation, enables formation of fine particles with a small particle size and narrow particle distribution, and a highly transparent and non-turbid pigment dispersion can be efficiently obtained. And preferred. In particular, a dispersion liquid in which pigment fine particles are precipitated in the laminar flow process while changing the pH as described above is particularly preferable because of excellent particle size, distribution thereof, dispersion stability, and productivity.

The equivalent diameter is also called an equivalent diameter and is a term used in the field of mechanical engineering. When an equivalent circular pipe is assumed for a pipe or channel having an arbitrary cross-sectional shape, the diameter of the equivalent circular pipe is called an equivalent diameter. The equivalent diameter (d _eq ) is defined as d _eq = 4 A / p, using A: the cross-sectional area of the pipe, and p: the wet wetting length (circumferential length) of the pipe. When applied to a circular tube, this equivalent diameter corresponds to the circular tube diameter. The equivalent diameter is used to estimate the flow or heat transfer characteristics of the pipe based on the data of the equivalent circular pipe, and represents the spatial scale (typical length) of the phenomenon. The equivalent diameter is in the square tube of one side ^{_{a d eq = 4a 2 / 4a}} = a, the equilateral triangle pipe of one side _{a d eq = a / √3,} d eq in a flow between paralleled plates having a channel height h = 2h (for example, see “Mechanical Engineering Encyclopedia” edited by Japan Society of Mechanical Engineers, 1997, Maruzen Co., Ltd.).

  When water is poured into the tube, a thin tube is inserted into its central axis and colored liquid is injected, the colored liquid flows as a single line while the flow rate of water is low, and the water flows on the tube wall. It flows straight in parallel. However, when the flow velocity is increased and reaches a certain flow velocity, the water flow suddenly becomes turbulent, and the colored liquid is mixed with the water flow to become a colored flow. The former flow is called laminar flow, and the latter is called turbulent flow.

Whether the flow is laminar or turbulent depends on whether the Reynolds number, which is a dimensionless number indicating the flow, is below a certain critical value. The smaller the Reynolds number, the easier it is to form a laminar flow. The Reynolds number Re of the flow in the pipe is expressed by the following equation.
Re = D <υ _x > ρ / μ
D is the equivalent diameter of the tube, <υ _x > is the average cross-sectional velocity, ρ is the density of the fluid, and μ is the viscosity of the fluid. As can be seen from this equation, the smaller the equivalent diameter, the smaller the Reynolds number. Therefore, in the case of an equivalent diameter of μm, it becomes easy to form a stable laminar flow. It can also be seen that the liquid physical properties of density and viscosity also affect the Reynolds number, and the smaller the density and the larger the viscosity, the smaller the Reynolds number and the easier it is to form a laminar flow. Here, the Reynolds number indicating the critical value is referred to as the critical Reynolds number. The critical Reynolds number is not always constant, but the next value is the standard.
Re <2300 laminar flow
Re> 3000 Turbulence
3000 ≧ Re ≧ 2300 Transient state

As the equivalent diameter of the flow path decreases, the surface area per unit volume (specific surface area) increases, but when the flow path becomes microscale, the specific surface area increases dramatically, and the heat transfer efficiency through the wall of the flow path is Become very expensive. Since the heat transfer time (t) in the fluid flowing through the flow path is expressed by t = d _eq ² / α (α: the thermal diffusivity of the liquid), the heat transfer time becomes shorter as the equivalent diameter becomes smaller. That is, when the equivalent diameter is 1/10, the heat transfer time is 1/100. When the equivalent diameter is microscale, the heat transfer speed is extremely fast.

  Specifically, the microreactor has a mixing space consisting of long channels with an equivalent diameter of micrometer size, and a plurality of liquids are introduced and distributed in the same longitudinal direction of the channel. By making them, these liquids can be brought into contact and mixed. For details of the microreactor, see, for example, W.W. Ehrfeld, V.E. Hessel, H.C. Loewe, “Microreactor”, 1Ed (2000) WILEY-VCH, etc. can be referred to.

If a microreactor is used, a conventional batch system using a large-capacity tank or the like as a reaction field, or a jet reactor (see US Pat. No. 6,537,364) in which droplets are jetted to collide in an air current In contrast, the reaction time and temperature between liquids can be precisely controlled.
In the case of the batch method, the reaction proceeds at the reaction contact surface at the initial stage of mixing, particularly between solutions with a high reaction rate, and the primary product generated by the reaction between the solutions continues to be reacted in the vessel. Therefore, there is a possibility that the product becomes non-uniform or the crystals of the product grow more than necessary and become coarse in the mixing container. On the other hand, according to the microreactor, the solution continuously circulates with almost no stagnation in the mixing container. Therefore, while the primary product generated by the reaction between the solutions stays in the mixing container, it continues. It is possible to prevent the reaction from being received, it is possible to take out a pure primary product that was difficult to remove in the past, and it is less likely to cause aggregation and coarsening of crystals in the mixing vessel There is.

  In terms of scale-up, when a small amount of experimentally produced chemical substances are produced in large quantities by a large-scale production facility, reproducibility may not be obtained in material properties and the like by using a batch system. Such inconvenience can be solved by the microreactor. In other words, by parallelizing (numbering up) production lines using microrear coolers according to the required production volume, the results obtained by one microreactor can be reproduced without impairing, efficiently and accurately. There is an advantage that mass production can be realized.

The microreactor may be produced by a usual method or material. The fluid control method includes a continuous flow method and a liquid droplet (liquid plug) method when classified by form, and an electric drive method and a pressure drive method when classified by driving force.
In the present invention, it is preferable to adopt a continuous flow system. In continuous flow type fluid control, it is preferable that the liquid mixing space in the microchannel can be filled with liquid. And it is preferable to drive the whole fluid by a pressure source such as a syringe pump prepared outside (pressure driving method). Although this method increases dead volume, it is a great advantage that a control system can be realized with a relatively simple setup.
Regarding the manufacturing method and control method of the microreactor, for example, paragraphs 0035 to 0046 of JP-A-2005-307154 can be referred to.

In the present invention, the length of the liquid mixing space comprising the microchannels of the microreactor is not particularly limited, but is preferably 1 mm or more and 10 m or less, more preferably 5 mm or more and 10 m or less, and more preferably 10 mm or more and 5 m or less. It is particularly preferred.
The number of the flow paths used in the present invention is not particularly limited, and the production volume of the pigment fine particle dispersion can be increased by arranging the flow paths in parallel (numbering up) as necessary.

  FIG. 1 is an exploded perspective view schematically showing one embodiment of a center collision type microreactor apparatus. The three-dimensional microreactor apparatus 100 of this embodiment is mainly configured by a supply block 11, a merge block 12, and a reaction block 13 each having a cylindrical shape. In order to assemble the microreactor device 80, the cylindrical blocks 11, 12, and 13 are arranged in a cylindrical shape by aligning the side surfaces with each other in this order. For example, each block is bolted in this state.・ Tighten together with nuts.

  Two annular grooves 15 and 16 are formed concentrically on the side surface 14 of the supply block 11 facing the merging block 12. When the microreactor apparatus 100 is assembled, the two annular grooves 15 are assembled. And 16 form ring-shaped channels through which the liquid B and the liquid A flow, respectively. And the through-holes 18 and 17 which reach the outer side annular groove 16 and the inner side annular groove 15 from the opposite side surface 24 which does not oppose the confluence | merging block 12 of the supply block 11 are formed, respectively. A supply means (a pump, a connecting tube, etc.) for supplying the liquid A is connected to the through hole 18 that communicates with the outer annular groove 16 out of the two through holes 18 and 17, and communicates with the inner annular groove 15. Supply means (a pump, a connection tube, etc.) for supplying the liquid B is connected to the through-hole 17 that performs the above operation. In FIG. 1, the liquid A is allowed to flow in the outer annular groove 16 and the liquid B is allowed to flow in the inner annular groove 15.

  A circular junction 20 is formed at the center of the side surface 19 of the junction block 12 facing the reaction block 13, and four long radial grooves 21 and four short radial grooves 22 are formed radially from the junction 20. Alternately drilled. These merging holes 20 and radial grooves 21 and 22 form a circular space that becomes the merging region 20 and a radial channel through which the liquids A and B flow in the assembled state of the microreactor device 100. Further, among the eight radial grooves 21 and 22, through holes 25 are formed in the thickness direction of the merge block 12 from the tip of the long radial groove 21, and these through holes 25 are formed in the supply block 11. It communicates with the outer annular groove 16 described above. Similarly, through holes 26 are formed in the thickness direction of the merging block 12 from the tips of the short radial grooves 22, and these through holes 26 communicate with the inner annular groove 15 formed in the supply block 11.

Further, at the center of the reaction block 13, one through hole 23 communicating with the merging portion 20 is formed in the thickness direction of the reaction block 13, and this through hole 23 becomes a liquid mixing space including a micro flow channel.
As a result, the liquid A flows from the through hole 18 of the supply block 11 through the outer annular groove 16, through the through hole 25 of the merge block 12, and through the supply channel of the long radiation groove 21. The four divided flows reach the merging portion 20. On the other hand, the liquid B flows from the through hole 17 of the supply block 11 through the inner annular groove 15, through the through hole 26 of the merge block 12, and through the supply channel of the short radiation groove 22. The four divided flows reach the merging portion 20. The split flow of the liquid A and the split flow of the liquid B merge with the respective kinetic energy in the merge section 20, and then flow into the microchannel 23 by changing the flow direction by 90 °.

  Other improvements include reactors with a Y-shaped channel, reactors with a cylindrical tube channel, and in these devices, when the two liquid flows reach the outlet in a laminar flow, they can be separated. An added device or the like can be used (see, for example, paragraphs 0049 to 52 and FIGS. 1 to 4 of JP-A-2005-307154). It is also preferable to use a planar microreactor or a three-dimensional microreactor in which the contact angle of two liquids and the number of contact channels are appropriately adjusted (see, for example, paragraphs 0044 to 0050 of Japanese Patent Application No. 2006-78637).

  The organic pigment fine particle dispersion can be dried to obtain an organic pigment fine particle solid. The drying method is not particularly limited as long as it is a normal method, and examples include drying methods such as freeze-drying and distillation under reduced pressure of a liquid as a medium (using an evaporator or the like). Although the content rate of the organic pigment mixed fine particles when solidified is not particularly limited, it is preferably 5 to 90% by mass, and more preferably 20 to 80% by mass.

  The organic pigment mixed fine particle dispersion of the present invention can be an excellent inkjet ink. Specifically, as described above, the dispersion in which the organic pigment fine particles are precipitated by the build-up method is purified and concentrated by centrifugation and / or ultrafiltration. To this, for example, a water-soluble high-boiling organic solvent such as glycerin or glycol is added. Furthermore, if necessary, a good ink-jet ink can be obtained by adding an agent for adjusting pH, surface tension, viscosity, or an additive for preserving. Moreover, the dispersion for high-performance color filters can be obtained by appropriately performing the above-described separation, concentration, adjustment of liquid properties, and the like.

  The organic pigment mixed fine particles contained in the dispersion of the present invention are preferably those in which a polymer of a polymerizable compound is fixed to the fine particles. Immobilization means a state in which all (or part of) the polymerizable compound contained is in contact with the organic pigment mixed fine particles in a homopolymerized or copolymerized state. At this time, the polymer may be present either on the surface or inside of the organic pigment mixed fine particles, as long as all (or part of) the polymer is in contact with the organic pigment mixed fine particles. It is preferable that they are bonded so as not to be detached even by movement in the dispersion. Here, the polymer means a compound produced as a result of polymerization of two or more molecules of the polymerizable compound, and it is not necessary that all the polymerizable compounds on the fine particles are involved in the polymerization reaction. It may remain.

  As the polymerizable compound, any of water-soluble and water-insoluble polymerizable compounds can be used, and there is no particular limitation as long as it is dispersible together with the organic pigment, but an ethylenically unsaturated monomer is preferable. Specifically, for example, (meth) acrylic acid ester compounds (for example, methyl acrylate, ethyl acrylate, butyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, cyclohexyl acrylate, methyl methacrylate, Ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, cyclohexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, propyl γ-hydroxyacrylate, δ-hydroxy Butyl acrylate, β-hydroxyethyl methacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylene glycol methyl methacrylate, ethylene glycol dimethacrylate , Methyl tetraethylene glycol dimethacrylate, and derivatives thereof), vinyl aromatic monomers (for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenyl) Styrene, p-chlorostyrene, p-ethylstyrene, p-butylstyrene, pt-butylstyrene, p-hexylstyrene, p-octylstyrene, p-nonylstyrene, p-decylstyrene, p-dodecylstyrene, 2 , 4-dimethylstyrene, 3,4-dichlorostyrene, α-methylstyrene, divinylbenzene, divinylnaphthalene, etc., and derivatives thereof), vinyl ester compounds (vinyl acetate, vinyl propionate, vinyl benzoate, etc., and derivatives thereof) ), N-vinylamide compounds (for example, N-biamide). Lupyrrolidone), (meth) acrylic acid amide compounds, alkyl-substituted (meth) acrylamide compounds, methacrylamide compounds, N-substituted maleimide compounds, vinyl ether compounds (vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether, di Vinyl ethers and derivatives thereof), olefin compounds (ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene, butadiene, isoprene, chloroprene, and derivatives thereof) diallyl phthalate, maleic anhydride Acid, (meth) acrylonitrile, methyl vinyl ketone, vinylidene chloride, and the like can be used.

  Furthermore, a water-soluble monomer having an anionic group such as a sulfonic acid group, a phosphoric acid group, and a carboxylic acid group is also used. For example, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, p-vinylbenzoic acid Examples thereof include monomers having a carboxyl group such as acids, or alkali metal salts, alkaline earth metal salts, ammonium salts, amine salts thereof, and the like. Specific examples are styrene sulfonic acid, sodium styrene sulfonate, 2-acrylamido-2-methylpropane sulfonic acid, 2-hydroxymethyl methacryloyl phosphate, 2-hydroxyethyl methacryloyl phosphate, and 3-chloro-2-hydroxypropyl methacryloyl phosphate. As mentioned. These may be used alone or in combination with each other.

  Among the polymerizable compounds, those in which the molecules have a hydrophilic / hydrophobic function separated are called polymerizable surfactants, reactive surfactants, or reactive emulsifiers, and are used for producing the dispersion of the present invention. It can be preferably used. For example, α, β-ethylenically unsaturated group such as vinyl group, allyl group, propenyl group, (meth) acryloyl group and ion dissociable group such as sulfonic acid group or salt thereof, and hydrophilic group such as alkyleneoxy group The thing which has is mentioned. These are generally used for emulsion polymerization and are anionic or nonionic surfactants having at least one unsaturated bond capable of radical polymerization in the molecule.

  The polymerizable surfactants may be used alone, in combination with different ones, or with a polymerizable compound other than the polymerizable surfactant. Preferable polymerizable surfactants include, for example, Kao Corporation, Sanyo Chemical Co., Ltd., Daiichi Kogyo Seiyaku Co., Ltd., Asahi Denka Kogyo Co., Ltd., Nippon Emulsifier Co., Ltd., Nippon Oil & Fats. Examples are commercially available from Co., Ltd., etc., described in “Cutting-edge Technology of Fine Particles / Powder, Chapter 1, Fine Particle Design Using Reactive Emulsifiers, pp23-31”, 2000 CMC Co., Ltd. And the like.

  The polymerization method of the polymerizable compound is not particularly limited as long as it can be polymerized in the organic pigment dispersion, but a method of generating a radical using a polymerization initiator and polymerizing is preferable. Although there are various triggers for initiating polymerization, it is preferable to use heat, light, ultrasonic waves, microwaves, or the like. As the polymerization initiator, water-soluble or oil-soluble persulfates, peroxides, azo compounds, and the like can be used. Specifically, ammonium persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide, t-butyl hydroperoxide, 2,2′-azobisisobutyro and tolyl, 2,2′-azobis (2-amidino (Propane) dihydrochloride, 2,2′-azobis (2-N-benzylamidinopropane) dihydrochloride, 2,2′-azobis [2-N- (2-hydroxyethyl) amidinopropane] dihydrochloride, etc. For example, the homepage (www.wako-chem.co.jp) of Wako Pure Chemical Industries, Ltd. has various water-soluble azo polymerization initiators, oil-soluble azo polymerization initiators, and polymer azo polymerizations. Initiators are described and available with a 10 hour half-life temperature and its structural formula. Although the addition amount of a polymerization initiator is not specifically limited, It is 0.1-30 mass% with respect to all the monomer components, More preferably, it is 1-20 mass%, Most preferably, it is 2-10 mass%.

  In the present invention, the dispersion may be copolymerized with a monomer that copolymerizes with the polymerizable compound. There is no particular limitation on the timing when the copolymerization monomer is contained, but it is preferable that at least one copolymerization monomer is contained in at least one of the mixed organic pigment solution and the aqueous medium. The copolymerization monomer is not particularly limited as long as it does not hinder the precipitation of fine particles and the stabilization of the dispersion, and examples thereof include the polymerizable compounds mentioned above.

  In the present invention, various inorganic or organic functional additives may coexist in the dispersion regardless of whether they are copolymerized. Although the time which contains a functional additive is not specifically limited, For example, the case where it adds to at least one of a mixed organic pigment solution and an aqueous medium is mentioned preferably. The functional additive is not particularly limited as long as it does not hinder the precipitation of fine particles and the stabilization of the dispersion. For example, a metal sequestering agent, a bactericidal agent, a fungicide, a fragrance, an ultraviolet absorber, an antioxidant, and a surface tension modifier. , Water-soluble resins, pH adjusters, urea and the like.

  In this embodiment, since the organic pigment is precipitated as mixed fine particles and the polymerizable compound coexisted in the dispersion as it is is polymerized, extremely high dispersion stability can be realized in the pigment dispersion. This action is considered as follows. Since the polymerizable compound is present in the process of depositing the pigment in the dissolved state to form fine particles, the polymerizable compound is adsorbed integrally with the precipitated fine particles, and the fine particles are efficiently surrounded by the polymerizable compound without gaps. For this reason, the adsorption state of the polymerizable compound, which cannot be obtained simply by mixing the pigment fine particles and the polymerizable compound, can be obtained. By carrying out the polymerization reaction as it is, the polymerizable compound can be surely polymerized so as to tightly enclose the entire surface of the pigment mixed fine particles, preferably firmly and uniformly fixed, and can be prevented from leaving. . In particular, when the polymerizable compound is a polymerizable surfactant, the stabilizing effect is further enhanced because it is more strongly adsorbed on the surface of the fine particles and surrounds the fine particles. Thus, by using a polymerizable compound, both the size control function at the time of build-up and the subsequent encapsulation function can be exhibited. Thereby, the finely dispersed pigment mixed fine particles can be encapsulated as they are, and high dispersion stability and storage stability can be imparted to nanometer-sized fine particles having a uniform particle diameter.

In the production method of the present invention, a preferred embodiment at the time of performing the polymerization treatment particularly in the pH conversion coprecipitation method will be described. The timing and method for polymerizing the polymerizable compound are not particularly limited. For example, the following two processes are shown as examples. Even if the polymerization reaction is performed during or after the process (1), the process It may be performed during or after (2) or both.
(1) A process of bringing the mixed organic pigment solution into contact with an aqueous medium.
(2) The process of concentrating and purifying the dispersion after contact of both liquids.

Similarly, the timing and method of addition of the polymerization initiator are not particularly limited. For example, the following four embodiments may be used, or any of them may be used in combination.
(1) Add to the mixed organic pigment solution.
(2) Add to aqueous medium.
(3) Add the mixed organic pigment solution after contacting the aqueous medium.
(4) Concentrate and purify the dispersion after contact of both liquids and add.

  In the present invention, the polymerizable compound is preferably contained in at least one of the mixed organic pigment solution and the aqueous medium, and is preferably contained in the mixed organic pigment solution. When other polymerizable compounds and dispersants are used in combination, the mode is not particularly limited. For example, they may be dissolved in either the organic pigment solution or the aqueous medium, or may be added to the dispersion after mixing. Good. In addition, when the fine particles are precipitated, liquids other than the mixed organic pigment solution or the aqueous medium may be mixed as necessary, and three or more liquids may be mixed simultaneously or sequentially. The polymerization reaction temperature can be selected according to the type of the polymerization initiator, and is preferably 40 ° C to 100 ° C, more preferably 50 ° C to 90 ° C, and particularly preferably 50 ° C to 80 ° C. The polymerization reaction time can be 1 to 12 hours, although it depends on the polymerizable compound used, its concentration, and the reaction temperature of the polymerization initiator.

Combined with additives such as UV absorbers, antioxidants, fragrances, fungicides, surface tension modifiers, water-soluble resins, bactericides, pH adjusters, urea, etc., for the purpose of increasing the fastness of organic pigment mixed fine particles May be. The timing and method of addition of these are not particularly limited. For example, the following four aspects may be used, and any of these may be performed in combination.
(1) Add to the mixed organic pigment solution.
(2) Add to aqueous medium.
(3) Add the mixed organic pigment solution after contacting the aqueous medium.
(4) Concentrate and purify the dispersion after contact of both liquids and add.
In order to adjust the degree of polymerization (molecular weight), various chain transfer agents (for example, catechols, alcohols, thiols, mercaptans) may be used.
In order to further improve the uniform dispersibility and storage stability of the pigment, the content of the polymerizable compound is preferably in the range of 0.1 to 1000 parts by mass, more preferably 100 parts by mass of the pigment. It is the range of 1-500 mass parts, Most preferably, it is the range of 10-250 mass parts. If this amount is too small, the dispersion stability of the organic pigment mixed fine particles may not be improved.

  The present invention will be described below in more detail based on examples, but the present invention is not limited to these examples. The maximum absorption wavelength of each pigment alone is the same as that described in Example 1, and a nanopigment spin-coated sample is prepared (that is, the sample is 1 s except that 4.0 g of the pigment is used alone). The same production method) and the values obtained by actually measuring the transmission spectrum are described.

(Example 1)
Pigment Yellow 128 (Formula (1) below) (Ciba Specialty Chemicals, CROMOPHTAL YELLOW 8GNP (trade name), maximum absorption wavelength (λmax) = 410 nm) 4.0 g, Pigment Orange 13 (Formula (2) below) (Tokyo Kasei Co., Ltd., maximum absorption wavelength (λmax) = 480 nm) 0.08 g, 28% sodium methoxide methanol solution (Wako Pure Chemical Industries, Ltd.) 3.7 g, Aqualon KH-10 (trade name) ) (Daiichi Kogyo Seiyaku Co., Ltd.) 3.2 g, N-vinylpyrrolidone (Wako Pure Chemical Industries, Ltd., purified by vacuum distillation) 0.8 g, polyvinylpyrrolidone K30 (trade name) 0.4 g (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 60 mL of dimethyl sulfoxide at room temperature to obtain an IE solution. The pH at this time exceeded 14, and measurement was impossible.
Distilled water was used as the IIE solution. As the microreactor apparatus, the central collision type microreactor apparatus of FIG. 1 having the following division number (number of flow paths) and the like was used.

(I) Number of supply flow paths (n): Divided into 5 for each of the two types of reaction liquids (a total of 10 flow paths merge. In addition, the apparatus of FIG. It is a device to do.)
(Ii) Width (W) of supply flow paths 21 and 22: 400 μm each
(Iii) Depth (H) of supply flow paths 21 and 22: 400 μm each
(Iv) Diameter (D) of merging region 20 800 μm
(V) Diameter (R) of microchannel 23 ... 800 μm
(Vi) Intersection angle between the central axes of the supply flow channels 21 and 22 and the micro flow channel 23 in the merge region 20 ... 90 °
(Vii) Material of the device: stainless steel (SUS304)
(Viii) Flow path machining method: Performed by micro electric discharge machining, and the sealing method of the three parts of the supply block 11, the merging block 12, and the reaction block 13 was performed by metal surface sealing by mirror polishing. Two Teflon (registered trademark) tubes having a length of 50 cm and an equivalent diameter of 1 mm were connected to the two inlets using a connector, and syringes containing IE solution and IIE solution were connected to the ends of the tubes and set in a pump. A Teflon (registered trademark) tube having a length of 1.5 m and an equivalent diameter of 2 mm was connected to the outlet of the connector.

The IE solution was delivered at a delivery rate of 150 mL / min, and the IIE solution was delivered at a delivery rate of 600 mL / min. Since a pigment dispersion was obtained from the tip of the tube outlet, it was collected and used as sample 1a. To 250 ml of the obtained liquid 1a, 0.64 g of V-50 (trade name) [2,2′-azobis- (2-amidinopropane) dihydrochloride, manufactured by Wako Pure Chemical Industries, Ltd.] was bubbled with nitrogen gas. After deaeration treatment according to No. 2, the sample was heated at 80 ° C. for 5 hours under a nitrogen atmosphere, and filtered through a back paper (No. 2 manufactured by Advantech Toyo Co., Ltd.), which was allowed to cool to room temperature, to obtain Sample 1b.
The volume average particle diameter Mv of the organic pigment mixed fine particles of Sample 1b was 28.7 nm, and the ratio of volume average particle diameter Mv / number average particle diameter Mn, which is an index of monodispersibility, was 1.56. Sample 1b was purified with ultrafiltration equipment (Advantech Toyo Co., Ltd., UHP-62K, molecular weight cut off: 50,000) while adding distilled water to eliminate the filtrate and keeping the volume constant. Concentration gave Sample 1c. The viscosity of the 5.0 mass% pigment dispersion 1c is 5.0 mPa.s. s.

(Evaluation of light resistance)
To the obtained dispersion 1c of 5.0% by mass of pigment, glycerin, olphine, and water are added to prepare an aqueous dispersion of 2.0% pigment, 10% by mass of glycerin, and 2% by mass of olphine. Spin coating was performed to obtain a sample 1s. The sample was set in a fading tester, and a light resistance test was performed by irradiating a xenon lamp with an illuminance of 170,000 lux for 4 days. As a UV filter, a TEMPAX filter (trade name) (manufactured by Eagle Engineering Co., Ltd., material is TEMPAX (trade name) glass made by SCHOTT) was disposed between the light source and the sample. The absorbance before irradiation (Abs.), The absorbance after irradiation, and the remaining ratio of absorbance (absorbance after irradiation ÷ absorbance before irradiation × 100) were 0.324, 0.269, and 83%, respectively.

(Example 2)
A 5% dispersion 2c and a spin coat sample 2s were obtained in the same manner as in Example 1 except that 0.04 g of the compound Pigment Orange 13 used in Example 1 was used. The viscosity of the dispersion 2c is 5.0 mPa.s. s. The absorbance of the sample 2s before and after the xenon irradiation test and the residual ratio of the absorbance were measured and listed in Table 1.

(Comparative Example 1)
A 5% pigment dispersion R1c and a spin coat sample R1s were obtained in the same manner as in Example 1 except that the compound Pigment Orange 13 used in Example 1 was not used. The viscosity of the dispersion 1c is 4.9 mPa.s. s. The absorbance of the sample R1s before and after the xenon irradiation test and the residual ratio of the absorbance were measured and listed in Table 1.

[Table 1]
-----------------------------------
Light resistance test (absorbance)
Glass-coated sample name Before irradiation 4 days after irradiation Residual rate (%)
-----------------------------------
1s 0.324 0.269 83
2s 0.320 0.248 78
R1s 0.313 0.210 67
-----------------------------------

As shown in Table 1, the pigment dispersion sample R1s for comparison using one kind of organic pigment had a light resistance that was too low to be practically insufficient.
In contrast, the dispersion liquid sample 1s of the present invention containing mixed fine particles of two kinds of organic pigments exhibits extremely high light resistance despite the nanometer-sized monodisperse build-up fine particles (sample 1s, 2s), and even if the amount of the minor component organic pigment was small, the remarkable effect was maintained (Sample 2s).

(Comparative Example 2)
Pigment Yellow 128 (Ciba Specialty Chemicals, CROMOPHTAL YELLOW 8GNP) 40 g, Pigment Orange 13 (Tokyo Chemical Co., Ltd.) 0.8 g, 28% sodium methoxide methanol solution (Wako Pure Chemical Industries, Ltd.) 37
g was dissolved in 600 mL of dimethyl sulfoxide at room temperature. 600 mL of this pigment alkali solution was added dropwise to 2400 mL of distilled water in a beaker with stirring over 30 minutes, and the resulting solid was filtered and dried to obtain 34 g of a mixed pigment solid (bulk body).
The resulting mixed pigment solid was mixed so that it was 20% by mass, styrene-acrylic acid-methyl methacrylate copolymer (molecular weight 10,000, acid value 160) 15% by mass, glycerin 10% by mass, and ion-exchanged water 55% by mass. The mixture was pulverized at 40 ° C. for 8 hours using a bead mill filled with 60% by volume of 0.3 mm zirconia beads and diluted with water to obtain a yellow pigment dispersion R2c having a pigment concentration of 5% by mass. . The average particle size of R2c is 77 nm (measurement was performed by diluting to 1% by mass of pigment), and the viscosity of the dispersion was 5.5 mPa.s. s.

  Table 2 shows the changes in viscosity when the dispersion samples 1c, 2c, R1c, and R2c were subjected to heat storage treatment at 60 ° C. for 100 hours and 240 hours, respectively. Further, these samples were subjected to a sedimentation acceleration test under a condition of 12000 rpm, 40 ° C., 60 minutes with a centrifuge and visually confirmed. As a result, sedimentation was observed in the dispersion R2c. On the other hand, no sedimentation was observed in the dispersions 1c and 2c, and a good state before the sedimentation treatment was maintained.

[Table 2]
------------------------------------
Viscosity (mPa.s) Dispersion liquid by precipitation treatment Before heating 60 ° C. 100 h 60 ° C. 240 h Precipitation formation --------------------------- ----------
1c 5.0 5.0 5.1 None 2c 5.0 4.9 5.0 None R1c 4.9 4.8 4.8 None R2c 5.5 7.3 8.1 (Precipitate formed) Yes- -----------------------------------

As shown in Table 2, the pigment dispersion sample R2c prepared by the breakdown method had a low dispersion stability with time and was insufficient in practice.
On the other hand, the dispersion containing the build-up pigment fine particles of the present invention was excellent without causing a large increase in viscosity or sedimentation even when stored for a long period of time.

  From the above results, according to the present invention, it is possible to solve the problem of the build-up method and achieve high dispersion stability and high light fastness at the same time while making nanometer-sized and monodisperse pigment fine particles. I understand that.

It is a disassembled perspective view which shows typically one embodiment of a center collision type | mold microreactor apparatus.

Explanation of symbols

100 reactor (microreactor)
DESCRIPTION OF SYMBOLS 11 Supply block 12 Merge block 13 Reaction block 16 Outer annular groove 15 Inner annular groove 17, 18 Through hole of supply block 20 Merge part (merging area)
21 Long radial groove 22 Short radial groove 23 Through-hole of reaction block (liquid mixing space consisting of micro flow path)
25, 26 Through-hole of merge block

Claims (13)

  Dispersion of organic pigment mixed fine particles having two or more kinds of organic pigments as particle components, wherein the mixed fine particles are precipitated by contacting a mixed organic pigment solution in which the two or more kinds of organic pigments are dissolved with an aqueous medium. An organic pigment mixed fine particle dispersion, characterized in that it is a nanometer-sized build-up pigment fine particle.   As the two or more kinds of organic pigments, a main component organic pigment is contained in an amount of 80% by mass or more based on the total pigment, and a subcomponent organic having a maximum absorption wavelength on the long wavelength side of 10 to 100 nm from the maximum absorption wavelength indicated by the main component organic pigment The organic pigment mixed fine particle dispersion according to claim 1, wherein at least one pigment is contained.   The organic pigment mixed fine particle dispersion according to claim 1 or 2, wherein the mixed fine particles have a volume average particle size (Mv) of 50 nm or less.   The ratio (Mv / Mn) between the volume average particle diameter (Mv) and the number average particle diameter (Mn) of the mixed fine particles is set to 1.8 or less. The organic pigment mixed fine particle dispersion described.   Solid matter of organic pigment mixed fine particles obtained by drying the dispersion according to any one of claims 1 to 4.   An organic pigment mixed fine particle dispersion characterized in that a mixed organic pigment solution in which two or more organic pigments are dissolved is brought into contact with an aqueous medium to precipitate and produce mixed fine particles having the two or more organic pigments as particle components. Manufacturing method.   The method for producing a dispersion of organic pigment mixed fine particles according to claim 6, wherein the mixed organic pigment solution is a solution in which the two or more organic pigments are dissolved with an alkali or an acid.   As the two or more kinds of organic pigments, the main component organic pigment is contained in an amount of 80% by mass or more in the total pigment, and the subcomponent organic pigment has a maximum absorption wavelength on the long wave side of 10 to 100 nm from the maximum absorption wavelength indicated by the main component organic pigment. One or more of these are contained, The manufacturing method of the organic pigment mixed fine particle dispersion of Claim 6 or 7 characterized by the above-mentioned.   The volume average particle diameter (Mv) of the mixed fine particles is 50 nm or less, The method for producing an organic pigment mixed fine particle dispersion according to any one of claims 6 to 8.   The ratio (Mv / Mn) between the volume average particle diameter (Mv) and the number average particle diameter (Mn) of the mixed fine particles is set to 1.8 or less, according to any one of claims 6 to 9, The manufacturing method of organic pigment mixed fine particle dispersion as described.   The method for producing an organic pigment mixed fine particle dispersion according to any one of claims 6 to 10, wherein the mixed organic pigment solution and an aqueous medium are contacted in a flow path of a microreactor.   12. The method of producing an organic pigment mixed fine particle dispersion according to claim 11, wherein an equivalent diameter of the flow path of the microreactor is 1 mm or less.   The method for producing an organic pigment mixed fine particle dispersion according to any one of claims 6 to 12, wherein the mixed organic pigment solution and the aqueous medium are contacted in a laminar flow process.

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