JP2013101297A - Colored liquid and colored composition in separated liquid state - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a colored liquid excellent in dispersion stability, with which a stable electrowetting device can be obtained.SOLUTION: The colored liquid is to be used for a device employing an optical modulation system of modulating color or brightness by moving or deforming a liquid by an external electric field, and the colored liquid comprises a nonpolar solvent and a coloring agent. The coloring agent is obtained by kneading a mixture containing at least a resin, a water-soluble organic solvent and a pigment by use of a closed kneading machine that includes a sealable stirring tank and a uniaxial or multi-axial stirring blade, in such a manner that the mass of the mixture during kneading is maintained in a range of 90 mass% or more with respect to the charge amount of the mixture before kneading. A colored composition in a separated liquid state is provided, which comprises the above colored liquid and a polar solvent that is not miscible with the colored liquid.

Description

  The present invention relates to a modulation method for moving a liquid using an external electric field, and more particularly to a colored liquid used in an electrowetting device, and a separate liquid colored composition.

  A modulation method for moving a liquid using an external electric field has been studied as an image display device or an optical element such as an optical shutter, an optical pickup device, and a liquid optical lens. Typical examples of these modulation methods include an electroosmosis method, an electrophoretic method, an electrofluidic method, and an electrowetting method.

  Among them, the electrowetting method has been studied as an image display device that does not consume power because it has a high contrast ratio and a wide viewing angle and does not require a front light or a backlight. As described in Patent Documents 1 and 2, the principle is based on a concept called “electrocapillary”. By applying or not applying voltage, droplets made of colored liquid existing in non-colored liquid are enlarged or reduced. (Alternatively, a colored image is formed by enlarging or reducing droplets made of a non-colored liquid present in the colored liquid.)

Such a liquid composed of a separated liquid non-colored liquid and a colored liquid (hereinafter referred to as a separated liquid colored liquid) needs to be separated, that is, not miscible, and therefore generally a nonpolar solvent such as silicone oil, A polar solvent such as water, alcohol or ethylene glycol is used, and a colorant is added to any of them.
For example, as an example of adding a colorant in a polar solvent, Patent Document 3 discloses an ionic liquid containing a room temperature molten salt in which a cation and an anion are combined in a polar solvent, a carboxyl group, a hydroxyl group, and a carbonyl group. In addition, it is disclosed that a colored liquid to which a self-dispersing pigment having a functional group such as a sulfone group, a hydroxyl group, or a phosphoric acid group is added is used. Patent Document 4 discloses the use of a colored liquid having a specific electric conductivity and ionic radius obtained by adding a pigment or a dye to a polar solvent having a specific viscosity and surface tension.
Further, as an example of adding a colorant in a nonpolar solvent, Patent Document 5 discloses that an organic pigment and / or an inorganic pigment, a solvent soluble or solvent dispersible in a nonpolar solvent such as decane, decalin or tetralin. It is disclosed to use a polymer dispersant and a colored liquid to which an aldehyde resin or a ketone resin is added.

JP-A-10-39800 Japanese Patent Laid-Open No. 10-74055 JP 2008-203282 A WO2011 / 017446 gazette Special table 2011-510336 gazette

  An object of the present invention is to provide a colored liquid that is excellent in dispersion stability and can provide a stable electrowetting device.

  The present inventors have found that the above-mentioned problems can be solved by using a pigment coated with a resin by a specific kneading method as a colorant to be used.

  That is, the present invention is a colored liquid containing a nonpolar solvent and a colorant, which is used in a light modulation type device that modulates color or brightness by moving or deforming the liquid by an external electric field, However, the mass of the mixture during kneading using a closed type kneader equipped with a sealable stirring tank and a uniaxial or multiaxial stirring blade for a mixture containing at least a resin, a water-soluble organic solvent, and a pigment. Provides a colored liquid which is a colorant obtained by kneading so as to be maintained in a range of 90% by mass or more with respect to the charged amount before kneading.

  Moreover, this invention provides the isolation | separation liquid coloring composition containing the coloring liquid of the said description and the polar solvent which is not miscible with the said coloring liquid.

  The present invention also provides use of the above-described colored liquid as a colorant for generating an image in a light modulation type device that modulates color or brightness by moving or deforming the liquid by an external electric field. To do.

  According to the present invention, it is possible to provide a colored liquid that is excellent in dispersion stability and from which a stable electrowetting device can be obtained.

(Nonpolar solvent)
The nonpolar solvent used in the colored liquid of the present invention is not particularly limited as long as it is a nonpolar solvent usually used in an electrowetting device, and a known one can be used. Specifically, for example, non-aqueous linear and / or branched or cyclic alkane having 4 to 30 carbon atoms, preferably pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, Cyclopentane, cyclohexane, cycloheptane, cyclooctane, methylcyclohexane, particularly preferably decane, undecane and dodecane or mixtures of these in any ratio; linear and / or branched and / or cyclic carbon atoms A haloalkane having 1 to 30 carbon atoms, preferably dichloromethane, chloroform, tetrachloromethane, dichloroethane, trichloroethane, tetrachloroethane, chlorocyclohexane, and regioisomers thereof; aromatic compounds having 6 to 22 carbon atoms, preferably benzene, Toluene, xyle , Mesitylene, or a mixture of any ratio thereof; or a hydrogenated aromatic compound having 10 to 22 carbon atoms, preferably tetralin, cis-decalin and trans-decalin, or a mixture of any ratio thereof, Particularly preferably, cis-decalin and trans-decalin;

  Aromatic compounds having 6 to 22 halogenated carbon atoms, preferably chlorobenzene, fluorobenzene, dichlorobenzene or difluorobenzene, trichlorobenzene or trifluorobenzene, chloronaphthalene or fluoronaphthalene, and their positional isomers; linear And / or branched and / or cyclic alcohols having 4 to 22 carbon atoms, preferably butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, benzyl alcohol, phenylethanol, cyclopen Butanol, cyclohexanol, cycloheptanol, or cyclooctanol, and their positional isomers; linear and / or branched and / or cyclic ethers, Preferably, diethyl ether, dipropyl ether, tert-butyl methyl ether, tert-amyl methyl ether, tert-amyl ethyl ether, dimethoxyethane, diethoxyethane, diglyme, triglyme, furan, tetrahydrofuran, tetrahydromethylfuran, dioxolane, Tetrahydrothiophene, tetrahydropyran, dioxane, methoxybenzene, methylthiobenzene, ethoxybenzene, and their positional isomers;

Linear and / or branched and / or cyclic ketones, preferably acetone, trichloroacetone, butanone, pentanone, hexanone, heptanone, octanone, nonanone, cyclopentanone, cyclohexanone, acetophenone, acetylacetone, and their positions Isomers;
Linear and / or branched and / or cyclic nitroalkanes, preferably nitromethane, nitroethane, nitrocyclohexane, and their positional isomers;
Nitroaromatic compounds having 6 to 22 carbon atoms, preferably nitrobenzene; linear and / or branched and / or cyclic amines, preferably tert-butylamine, diaminoethane, diethylamine, triethylamine, tributylamine, pyrrolidine , Piperidine, morpholine, N-methylaniline, and N, N-dimethylaniline and their positional isomers; hexamethyldisilane, diphenyldimethylsilane, chlorophenyltrimethylsilane, phenyltrimethylsilane, phenethyltris (trimethylsiloxy) silane, phenyl Tris (trimethylsiloxy) silane, polydimethylsiloxane, tetraphenyltetramethyltrisiloxane, poly (3,3,3-trifluoropropylmethylsiloxane), 3,5,5 7-triphenylnonamethylpentasiloxane, 3,5-diphenyloctamethyltetrasiloxane, 1,1,5,5-tetraphenyl-1,3,3,5-tetramethyl-trisiloxane, and hexamethylcyclotrisiloxane Hydrofluoroether, chlorodifluoromethane, 1,1,1,2-tetrafluoroethane, pentafluoroethane, difluoromethane, trifluoromethane, 1,1,1,2,3,3,3-heptafluoropropane, 1; , 1-difluoroethane, 1,1,1,3,3,3-hexafluoropropane, octafluoropropane, or mixtures of any of the above solvents.
Among these, decane, dodecane, decalin, tetralin, a mixture thereof, or a substance containing these substances as a main component is particularly preferable.

(Coloring agent)
The colorant used in the present invention is a closed kneader equipped with a stirrer capable of sealing a mixture containing at least a resin, a water-soluble organic solvent, and a pigment, and a uniaxial or multiaxial agitator blade, It is a colorant obtained by kneading so that the mass of the mixture during kneading is maintained in the range of 90% by mass or more with respect to the charged amount before kneading.

(Colorant: Resin)
The resin used in the present invention is not particularly limited, and various resins can be used. For example, polyvinyl resin, polyester resin, amino resin, acrylic resin, epoxy resin, polyurethane resin, polyether resin, polyamide resin, unsaturated polyester resin, phenol resin, silicone resin, fluorine Based polymer compounds and the like. These resins preferably contain a hydrophilic group and a hydrophobic group from the viewpoint of the dispersion stability and long-term storage stability of the resulting colorant. Examples of resins that can be easily introduced with hydrophilic groups or hydrophobic groups include styrene resins, acrylic resins, maleic resins, polyvinyl acetate resins, polyvinyl sulfonate resins, polyester resins, and polyurethane resins. And polyamide resins, polyvinyl alcohol resins, polypyrrolidone resins, and cellulose resins.

(Colorant: Water-soluble organic solvent)
The water-soluble organic solvent used in the present invention is not particularly limited, and known ones can be used. For example, glycols such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, polyethylene glycol, and polypropylene glycol; diols such as butanediol, pentanediol, hexanediol, and diols similar to these; propylene laurate Glycol esters such as glycol; glycol ethers such as diethylene glycol monoethyl, diethylene glycol monobutyl, diethylene glycol monohexyl ether, propylene glycol ether, dipropylene glycol ether, and cellosolve containing triethylene glycol ether; methanol, ethanol, isopropyl alcohol , 1-propanol, 2-p Alcohols such as panol, 1-butanol, 2-butanol, butyl alcohol, pentyl alcohol, and alcohols homologous thereto; or lactones such as sulfolane; γ-butyrolactone; N- (2-hydroxyethyl) pyrrolidone, etc. Other various solvents known as water-soluble organic solvents such as lactams; glycerin and derivatives thereof can be mentioned. These water-soluble organic solvents can be used alone or in combination.

  Among them, polyhydric alcohols having a high boiling point and low volatility and high surface tension are preferable, and glycols such as diethylene glycol and triethylene glycol are particularly preferable.

  In the present application, the water-soluble organic solvent is considered to dissolve, partially dissolve, or swell the resin. By kneading the pigment with the resin dissolved, partially dissolved, or swollen, the surface of the pigment is obtained. It is considered that a uniform film of resin can be easily formed. Therefore, it is estimated that a colored liquid having excellent dispersion stability and capable of obtaining a stable electrowetting device can be obtained.

  From such a viewpoint, the water-soluble organic solvent is preferably used in a mass ratio of 1/5 or more of the pigment described later, and most preferably 1/3 or more. By using the water-soluble organic solvent in a mass ratio of 1/3 or more of the pigment, the kneading can always proceed in the presence of a certain amount of solvent from the start to the end of the kneading step. As a result, it is presumed that the kneading process can be advanced while maintaining the resin in a dissolved state as well as depending on the resin, while maintaining a semi-dissolved or swollen state, and the resin coating on the pigment surface is performed well. The

  On the other hand, although the quantity with respect to the said resin is arbitrary, it is preferable to prepare so that it may become about 1 / 2-5 / 1 of the said resin by mass ratio, Preferably it will be 1 / 1-4 / 1. If the mass ratio is less than ½ of the resin, it may be difficult to dissolve, partially dissolve, or swell depending on the type of resin. On the other hand, when the mass ratio exceeds 5/1 of the resin, the viscosity of the resulting kneaded product is too low and sufficient kneading cannot be performed, and the desired pigment dispersibility may not be obtained.

(Colorant: Pigment)
The pigment used in the present invention is at least one pigment selected from known and commonly used organic pigments or inorganic pigments. In addition, the present invention can be applied to either an untreated pigment or a treated pigment.

Examples of organic pigments include perylene / perinone compound pigments, quinacridone compound pigments, phthalocyanine compound pigments, anthraquinone compound pigments, phthalone compound pigments, dioxazine compound pigments, isoindolinone compound pigments, and isoindoline compounds. Examples thereof include pigments, diketopyrrolopyrrole compound pigments, insoluble azo compound pigments, soluble azo compound pigments, condensed azo compound pigments, and aniline black pigments. Specific examples of the organic pigment are as follows, for example.
Examples of perylene / perinone compound pigments include C.I. I. PigmentViolet 29, C.I. I. Pigment Red 123, 149, 178, 179, C.I. I. Pigment Black 31, 32, C.I. I. Pigment Orange 43 and the like.
Examples of quinacridone compound pigments include C.I. I. Pigment Violet 19, 42, C.I. I. Pigment Red 122, 202, 206, 207, 209, C.I. I. Pigment Orange 48, 49 and the like.
Examples of the phthalocyanine compound pigment include C.I. I. Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, C.I. I. Pigment Green 7, 36 and the like.
Examples of the anthraquinone compound pigment include C.I. I. Pigment Blue 60, C.I. I. Pigment Yellow 24, 108, C.I. I. Pigment Red 168, 177, C.I. I. Pigment Orange 40 and the like.
Examples of the phthalone compound pigment include C.I. I. And pigments such as Pigment Yellow 138.
Examples of the dioxazine compound pigment include C.I. I. Pigment Violet 23, 37, and the like.
Examples of isoindolinone compound pigments include C.I. I. Pigment Yellow 109, 110, 173, C.I. I. Pigment Orange 61 and the like.
Examples of isoindoline-based compound pigments include C.I. I. Pigment Yellow 139, 185, C.I. I. Pigment Orange 66, C.I. I. Pigment Brown 38 and the like.
Examples of the diketopyrrolopyrrole compound pigment include C.I. I. Pigment Red 254, 255 and the like.
Examples of insoluble azo compound pigments include C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 55, 73, 74, 81, 83, 97, 130, 151, 152, 154, 156, 165, 166, 167, 170, 171, 172, 174, 175, 176, 180, 181, 188, C.I. I. Pigment Orange 16, 36, 60, C.I. I. Pigment Red5, 22, 22, 31, 112, 146, 150, 171, 175, 176, 183, 185, 208, 213, C.I. I. PigmentViolet 43, 44, C.I. I. Pigment Blue 25, 26 and the like.
Examples of the soluble azo compound pigment include C.I. I. Pigment Red 53: 1, 57: 1, 48 and the like.
Examples of the condensed azo compound pigment include C.I. I. Pigment Yellow 93, 94, 95, 128, 166, C.I. I. Pigment Orange 31C. I. Pigment Red 144, 166, 214, 220, 221, 242, 248, 262, C.I. I. Pigment Brown 41, 42 and the like.
Examples of the aniline black pigment include C.I. I. Pigment Black 1.

  Examples of inorganic pigments include titanium oxide, zinc sulfide, lead white, zinc white, lithbon, antimony white, basic lead sulfate, basic lead silicate, barium sulfate, calcium carbonate, gypsum, silica, carbon black, iron black. , Titanium black, cobalt violet, vermillion, molybdenum orange, red lead, bengara, chrome lead, cadmium yellow, zinc chromate, yellow ocher, chromium oxide, ultramarine, bitumen, cobalt blue and the like.

  By increasing the amount of the pigment added to the mixture as much as possible, the pigment concentration of the non-volatile content of the kneaded product can be increased. From this point of view, the charging amount is preferably 35% by mass or more, more preferably 40% by mass or more, based on the total amount of the mixture. Further, by increasing the amount of charging, the amount of resin charging can be relatively reduced, and excess resin that does not contribute to the coating of the pigment can be reduced. Excess resin may exist as a residual resin after kneading, and may be dissolved or swelled in a non-polar solvent after being made into a colored liquid, which may adversely affect the viscosity increase or dispersibility of the colored liquid itself. .

  Moreover, it is preferable that the content ratio of the said pigment and the said resin is 10 / 0.5-10 / 20 by mass ratio, More preferably, it is 10 / 0.5-10 / 10. If the resin is less than the above ratio, the dispersion stability of the resulting colored liquid may be reduced. On the other hand, if the resin is more than the above ratio, the free resin increases and the viscosity of the colored liquid becomes a device. May increase more than necessary.

The higher the solid content ratio in the mixture, the higher the viscosity of the kneaded product during kneading, and the greater the shear (shearing force) applied to the kneaded product by the kneader during kneading, thereby pulverizing the pigment in the kneaded product And pigment coating with resin can proceed simultaneously. From such a viewpoint, the solid content ratio is preferably 40% by mass or more, and more preferably 50% by mass or more.
Also, from the viewpoint of keeping the viscosity high and constant, the kneading method described below uses a closed kneader, and the mass of the mixture during kneading is in the range of 90% by mass or more with respect to the charged amount before kneading. It is necessary to knead so that it may be maintained.

(Colorant: kneading method)
The mass of the mixture during kneading is 90% by mass or more with respect to the charged amount before kneading, using a closed kneader equipped with a hermetically sealed stirring tank and a uniaxial or multiaxial agitating blade. The colorant used in the present application can be obtained by kneading so as to be maintained in the above range.
In the present invention, “using a closed-type kneader and kneading so that the mass of the mixture during kneading is maintained in a range of 90% by mass or more with respect to the charged amount before kneading” means water-soluble organic It means kneading so that the solvent or the like does not substantially evaporate. By doing so, a certain amount of water-soluble organic solvent is always present in the mixture from the start to the end of kneading. As a result, the water-soluble organic solvent that wets the surface of the pigment in the initial stage of kneading is replaced with a resin that is preferably dissolved, swollen or partially dissolved by the solvent, and the coating of the pigment with the resin proceeds smoothly, and the resin is sufficient. It is assumed that a coated pigment can be obtained. Further, even after the completion of the kneading, almost the same amount of the solvent remains as at the start of the kneading, so that the dissolution and dispersion of the mixture after the kneading can proceed in a very short time.
The mass of the mixture during the kneading is preferably as the rate of change in mass is smaller because the kneading conditions during the kneading are kept constant, and more preferably when kneaded so as to be maintained in the range of 95% by mass or more.

  The stirring blades may be uniaxial or multiaxial, but two or more stirring blades are preferable in order to obtain a high kneading action. When a kneader having such a structure is used, a kneaded product for an aqueous pigment dispersion is produced and then diluted with a water-soluble solvent directly in the same stirring tank and dispersed to produce an aqueous pigment dispersion. Can do.

Examples of such an apparatus include a Henschel mixer, a pressure kneader, a Banbury mixer, and a planetary mixer. In the present invention, the kneader is preferably a planetary mixer. The planetary mixer has a structure in which the kneaded material in the stirring tank is stirred and kneaded using biaxial stirring blades that rotate and revolve with each other, and the dead space where the stirring blades do not reach in the stirring tank Less is. Moreover, although the shape of a blade | wing is thick and can apply high load, on the other hand, it can also be used like the normal stirrer which rotates a stirring blade in a stirring tank. For this reason, there is a wide range of materials to be kneaded from the high load region to the low load region, and one or both of water and a water-soluble organic solvent are added to the kneaded material after completion of the kneading for dilution. All of the stirring and dispersion can be performed in the same mixer without removing the kneaded product from the planetary mixer.
In addition, since the kneaded product of the present invention is kneaded in a state where the solid content ratio composed of the pigment and the resin is high, the viscosity varies in a wide range depending on the kneaded state of the kneaded product. It is possible to deal with a wide range up to the viscosity.

  1 to 3 show an example of the configuration of a planetary mixer. In the figure, reference numeral 1 denotes a stirring tank, and this hollow cylindrical stirring tank 1 is divided into two substantially vertically. Inside the upper surface of the upper member 2 of the agitation tank 1, as shown in an enlarged view in FIG. 2, agitation blades 4 and 5 composed of frame-type blades are rotatably provided.

  And at the time of stirring, the upper member 2 and the lower member 3 are integrated, and it becomes a closed system. Then, as shown in FIG. 3, the rotating shafts themselves of the stirring blades 4 and 5 are rotated (revolved) by the rotor 6 around the same common shaft and shifted in phase in the same direction by 180 degrees. The kneading objects loaded in the stirring tank 1 are kneaded while the stirring blades 4 and 5 rotate (rotate, that is, planetary motion (planetary motion)). In addition, what was shown in FIG. 3 is the locus | trajectory of the front-end | tip of the two stirring blades 4 and 5 in one revolution of the stirring tank 1. FIG. By such a movement of the stirring blade, the kneading efficiency and the uniform kneading can be further improved as compared with the kneading apparatus in which the rotation shaft position of the stirring blade is fixed.

  In the planetary mixer, a powerful shearing force acts between the stirring blades 4 and 5 and between the stirring blades 4 and 5 and the inner surface of the stirring tank 1 by such planetary motion of the stirring blades 4 and 5. High stirring, kneading and dispersing action can be obtained.

  Various blade shapes such as hook type, frame type, and twist type have been proposed for the blades used in the planetary mixer, but any blade can be used and specified in the present invention. However, it is necessary to have strength that can withstand the viscosity of the kneaded product, and a frame mold is preferable from the viewpoint of strength, kneadability and the like.

  Further, the direction of rotation and revolution may be the same direction, different direction, etc., but can be used properly depending on the characteristics of the raw materials used. Various combinations of rotation and revolution speed ratios are conceivable, but each rotation speed and rotation speed ratio can be selected according to the characteristics of the raw materials used.

  When kneading using a closed kneader such as a planetary mixer, the current consumption gradually increases with time, reaches a maximum value within about 30 minutes, and then gradually decreases.

  That is, when the resin is mixed with the water-soluble organic solvent and the pigment while being heated to a predetermined temperature (for example, 40 to 70 ° C. depending on the type of resin), the resin becomes a water-soluble organic solvent. Then, it dissolves, partially dissolves or swells, becomes viscous, and is mixed with the pigment, whereby a large load is applied to the rotation of the stirring blades 4 and 5. At this time, a large shearing force is applied to the material between the stirring blades 4 and 5 and between the stirring blades 4 and 5 and the stirring tank 1, and the pigment is finely pulverized. Thoroughly dispersed, mixed and coated with resin. In particular, when a closed kneader such as a planetary mixer is used, effective kneading is performed, so that the resin, the pigment, and the water-soluble organic solvent are almost completely mixed within about 30 minutes, and the stirring blade 4 5 is reduced. As a result, current consumption gradually decreases.

  Thus, in the present invention, when mixing is performed using a closed kneader such as a planetary mixer, one or more consumptions are shown in the graph of the relationship between the kneading time and the power consumption of the kneader (planetary mixer). The characteristic that the maximum value of electric power is obtained is seen.

  Since the kneaded material produced in the kneading step of the present invention is finely divided into pigments and coated with a resin, a colorant can be obtained by heating, drying and pulverizing the previous kneaded material as it is. I can do it. For drying, a known drying device such as a box-type dryer, a vacuum dryer, or a band dryer can be used. For the pulverization, a known pulverization apparatus such as a mortar, hammer mill, disk mill, pin mill, jet mill or the like can be used.

  To obtain a colorant with a stronger coating state, an aqueous medium is added to the kneaded product, mixed, and stirred to liquefy, lower the viscosity, and a mixing step is performed to disperse the pigment coated with the resin in the aqueous medium. It is preferable. In the mixing step, liquefaction may be performed at once by adding the aqueous medium all at once, but the total addition amount is divided and added, and after the addition, the whole mixture becomes uniform, and then the mixture is homogenized. In order to realize uniform liquefaction, it is preferable to perform the following stirring. Alternatively, when the aqueous medium is added in divided portions in this way, a small amount of the aqueous medium may be added continuously over the entire time of the required mixing step. Especially when the volume of the mixture when adding, mixing and stirring the aqueous medium is large and it takes a period for the stirred aqueous medium to be mixed uniformly, the aqueous medium can be added in portions or continuously in small portions. It is preferable to add.

The aqueous medium used here is mainly composed of water or a water-soluble organic solvent compatible with water. Moreover, as a water-soluble organic solvent used here, the thing similar to the water-soluble organic solvent used in the kneading | mixing process can be used.
By the addition of such an aqueous medium, the solid content ratio of the mixture is lowered to become a highly viscous liquid.
In this step, it is possible to disperse the kneaded material in the aqueous medium only by mixing and stirring with a normal stirrer. However, after adding, mixing and stirring the aqueous medium, a high shear force can be obtained using a dispersing device. You may perform the distributed processing accompanied by. As such a dispersing device, a known dispersing device can be used. In the case of using a media, a paint shaker, a ball mill, an attritor, a basket mill, a sand mill, a sand grinder, a dyno mill, a disperse mat, an SC mill, a spike mill. And an agitator mill. Examples of media that do not use media include juice mixers, ultrasonic homogenizers, nanomizers, resolvers, dispersers, and high-speed impeller dispersers. Among these, dispersers using media are preferable because of their high dispersibility.
After the mixing step, filtration and washing are performed to obtain a water-containing cake. As a filtration method, known methods such as suction filtration, pressure filtration, and centrifugation can be used. A colorant can be obtained by heating, drying and crushing the water-containing cake. Drying can be performed by a known drying device such as a box-type dryer, a vacuum dryer, a band dryer, or a spray dryer. For the pulverization, a known pulverizer such as a mortar, a hammer mill, a disk mill, a pin mill, or a jet mill can be used.

(Coloring agent: blending amount)
The amount of the colorant added to the nonpolar solvent is preferably in the range of 1 to 50% by weight, more preferably in the range of 2 to 10% by weight.

  The colorant used in the non-polar coloring liquid for electrowetting is desired to have as low conductivity as possible.For example, pigments such as carbon black, iron black, petal, and chrome yellow have high conductivity. If it is used as it is, the electrical conductivity of the colored liquid obtained becomes too high. Since the colorant used in the present application is coated with a resin, the electrical conductivity of the obtained colored liquid can be reduced. In particular, when the pigment is a pigment such as carbon black or iron black, it is useful for an electrowetting device that modulates the brightness of light passing through the device.

(Other additives)
In the colored liquid of the present invention, surfactants, dispersants, wetting agents, thickeners, preservatives, viscosity stabilizers, grinding aids, fillers, precipitation preventions are also included within the range not impairing the effects of the present invention. Additives such as an agent, a photoprotective agent, an antioxidant, a biocide, a deaerator / antifoaming agent, a foaming inhibitor, and a baking inhibitor may be added. It is desirable to keep these to such an extent that the conductivity is not increased. For example, usable surfactants include polyalkylene glycols and derivatives thereof. Examples of the dispersant include polyamide, polyester, polyacrylate, polyvinylazolidones, polystyrene, polyepoxide, polyurethane, and polyvinyl halogen.

As the dispersant, a known pigment dispersant generally used for pigment dispersion can be used. Examples include surfactants, pigment intermediates or derivatives, dye intermediates or derivatives, or polyimide resins such as polyethyleneimine, polyamide resins, polyurethane resins, polyester resins, acrylic resins, poly Examples thereof include resin type dispersants such as ether resins. This can be synthesized and used, or a commercially available resin-type dispersant can be appropriately used.
Examples of commercially available resin-type dispersants include “DISPERBYK-130”, “DISPERBYK-161”, “DISPERBYK-162”, “DISPERBYK-163”, “DISPERBYK-166”, and “DISPERBYK-170” manufactured by BYK Chemie. ], "DISPERBYK-171", "DISPERBYK-174", "DISPERBYK-180", "DISPERBYK-182", "DISPERBYK-183", "DISPERBYK-184", "DISPERBYK-185", "DISPERBYK-2000", “DISPERBYK-2001”, “DISPERBYK-2050”, “DISPERBYK-2070”, “DISPERBYK-2096”, “DISPERBYK-” 150 ”,“ DISPERBYK-2155 ”, BASF products“ EFKA1503 ”,“ EFKA4008 ”,“ EFKA4010 ”,“ EFKA4015 ”,“ EFKA4020 ”,“ EFKA4046 ”,“ EFKA4047 ”,“ EFKA4050 ”,“ EFK40A ”,“ E40A ” EFKA4080, EFKA4300, EFKA4330, EFKA4340, EFKA4510, EFKA4520, EFKA4530, EFKA5054, EFKA6220, EFKA6225A, EFKA7411F , "EFKA7441", "EFKA7461", "EFKA7496", "EFKA7497", "Solspa" manufactured by Lubrizol "Sol Sparse 9000", "Sol Sparse 13240", "Sol Sparse 13650", "Sol Sparse 11200", "Sol Sparse 13940", "Sol Sparse 17000", "Sol Sparse 18000", "Sol Sparse 20000", "Sol Sparse 21000", ""Sol Sparse 20000", "Sol Sparse 24000", "Sol Sparse 26000", "Sol Sparse 27000", "Sol Sparse 28000", "Sol Sparse 32000", "Sol Sparse 36000", "Sol Sparse 37000", "Sol Sparse 38000", "Sol Sparse 41000", ""Sol Sparse 42000", "Sol Sparse 43000", "Sol Sparse 46000", "Sol Sparse 54000", "Sol Spa "Ace 71000", Ajinomoto Fine Techno Co., Ltd. products Ajisper "PB-711", "Azisper PB-821", "Azisper PB-822", "Azisper PB-814", "Azisper PB-824", Evonik products "TEGO Dispers 610", "TEGO Dispers 610S", "TEGO Dispers 630", "TEGO Dispers 650", "TEGO Dispers 651", "TEGO Dispers 670", "TEGO Dispers 670", "TEGO Dispers 670", "TEGO Dispers 670" , "TEGO Dispers 750W", "TEGO Dispers 752W", "TEGO Dispers 755" W "," TEGO Dispers 760W ", etc. can be used.

(Method for producing colored liquid)
The colored liquid of the present invention can be obtained by a known method for producing a pigment dispersion. As an example, a mixture in which the colorant, a non-polar solvent, and the additive as necessary are added can be obtained by dispersing the pigment coated with the resin using a normal dispersing machine such as a bead mill. it can. Moreover, after preparing a high concentration dispersion (mill base) using an ordinary dispersing machine such as a bead mill in advance, it can be adjusted by further mixing and stirring to a desired viscosity with a nonpolar solvent and diluting. The timing of addition of the additive can be appropriately selected depending on the type, such as before dispersion or after dispersion.

  As a stirring / dispersing device for dispersing a pigment, in addition to a bead mill, for example, an ultrasonic homogenizer, a high-pressure homogenizer, a paint shaker, a ball mill, a roll mill, a sand mill, a sand grinder, a dyno mill, a disperse mat, an SC mill, and a nanomizer are commonly used. A variety of dispersers can be used.

  The relative permittivity of the colored liquid thus obtained is preferably less than 25. Moreover, the response speed in switching of light modulation can be improved when the viscosity is low. For this purpose, the viscosity of the colored liquid is preferably less than 300 mPa · s, more preferably less than 100 mPa · s at 25 ° C.

(Polar solvent)
The separated liquid coloring composition of the present invention contains the coloring liquid and a polar solvent that is immiscible with the coloring liquid.
Non-miscible polar solvents include water, glycol, alcohol, polyol, ether, ester, ketone, acetal, ketal, lactone, carbonate, lactam, urethane (carbamate), urea, pyrrolidine, pyrrolidone, sulfone, sulfoxide, amide, etc. Yes, specifically, for example, water, methanol, ethanol, isopropanol, n-propanol, 1,2-propylene glycol, 1,3-propylene glycol, ethylene glycol, triethylene glycol, tetraethylene glycol, glycerin, 1,4 -Butylene glycol, diethylene glycol, dipropylene glycol, ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 1,2-cyclohexane carbonate, glycerin linker Dimethyl carbonate, diethyl carbonate, acetone, acetophenone, pyridine, dimethyl malonic acid, diacetone alcohol, hydroxypropyl carbamate, β-hydroxyethyl carbamate, formamide, N-methylformamide, dimethylformamide, N-methylacetamide, dimethylacetamide, Dimethyl sulfoxide, sulfolane, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, acetoacetone, cyclohexanone, ethyl acetoacetate, ethyl-L-lactic acid, pyrrole, N-methylpyrrole, N-ethyl Pyrrole, 4H-pyran-4-one, 1,3-dimethyl-2-imidazolidinone, morpholine, N-ethylmorpholine, N-formylmorpholine, β- Propiolactone, β-valerolactone, β-hexalactone, γ-butyrolactone, γ-valerolactone, γ-hexalactone, γ-heptalactone, γ-octalactone, γ-nonalactone, γ-decalactone, δ-valerolactone , Δ-hexalactone, δ-heptalactone, δ-octalactone, δ-nonalactone, δ-decalactone, and any combination thereof.

These polar solvents preferably exhibit a higher dielectric constant than the colored liquid. For the purpose of imparting a higher relative dielectric constant, an electrolyte such as a salt that undergoes ion dissociation in a polar solvent can be added. The ion may be a cation or an anion. Specifically, for example, pyrazoline, 2-imidazoline, pyrazole, imidazoline-2-thione, 1,2,3-thiazole, 1,2,4-thiazole, IH-tetrazole, oxazoline, 5-oxazolone, isoxazole, oxazole 2-thiazoline, isothiazole, thiazole, 1,2,3-oxadiazo, ie 1,2,4-oxadiazo, ie 1,2,5-oxadiazo, ie 1,3,4-oxadiazole, 1,3 , 4-thiadiazole, LH-pyridin-2-one, piperazine, pyrididine, 1,2,3-triazine, 1,2,4-triazine, oxazine, thiomorpholine, oxadiazine, oxathiazone, indoline, indole, carbazole, indazole, Benzimidazole, quinoxaline, Salts containing cations such as phthalazine, 1,5-naphthyridine, phenazine, benzothiazole, 2H-l 1,4-benzoxazine, phenoxazine, phenothiazine and the like can be used.
The addition amount can be appropriately selected according to a desired relative dielectric constant. For example, it can be used within a range of 10% by weight or less.

(Coloring agent)
The polar solvent may be colored as necessary. The colorant is not particularly limited as long as it is used as a colorant, and organic pigments, inorganic pigments and the like used as the above-mentioned colorant can be used.
When used as a device, it is preferable to select a dye having a color different from the color used for the nonpolar solvent. Among them, those having high color purity and color density and high transparency are preferable. Further, a liquid colored cyan (C), magenta (M), yellow (Y), green or white as necessary, and black (K) using a modified pigment using a black pigment as the colored liquid. It is possible to display a full-color image by using a colored liquid introduced into a pixel of an electrowetting device.

  In addition, the polar solvent includes a surfactant, a dispersant, a wetting agent, a thickening agent, a preservative, a viscosity stabilizer, a grinding aid, a filler, and a suspending agent as long as the effects of the present invention are not impaired. Additives such as a photoprotective agent, an antioxidant, a biocide, a deaerator / antifoaming agent, a foaming inhibitor, and a baking inhibitor may be added. For example, usable surfactants include anionic surfactants such as alkyl sulfonates, alkyl benzene sulfonates, and alkyl carboxylates, cationic surfactants such as alkyl ammonium salts and alkyl pyridinium salts, and polyalkylene glycols. And nonionic surfactants such as derivatives thereof and the like, but are not limited thereto.

(Electrowetting device)
The colored liquid of the present invention can be suitably used for an electrowetting device that moves the colored liquid using an external electric field. In particular, since a pigment is used as a coloring matter, the light resistance is excellent. Among them, it is preferable to use it for an image display device and to exhibit the stable driving of the device for a long time to the maximum by the dispersion stability which is the effect of the present invention.
An example of an electrowetting device that can use the non-conductive colored liquid will be given. That is, a display space is provided between the layers provided with electrodes, and the display space is filled with the separated liquid coloring composition containing the colored liquid and a polar solvent that is immiscible with the colored liquid. ing.
The layer on the display side of the display space is a transparent layer through which the colored liquid can be seen, while the layer on the non-display side is a light scattering layer, and the display side space is applied when voltage is applied to the colored liquid. Further, the colored liquid is moved by an electrowetting phenomenon, or the surface area on the display side is increased for color display.

  When a light scattering molecule is blended in the polar solvent to form a light scattering fluid, the light scattering layer may not be disposed on the non-display side layer.

Specifically, an upper layer on the display side, an intermediate layer made of a light scatterer having a through hole, and a lower layer are provided, and the upper space on the display side, the intermediate layer and the lower layer are provided between the upper layer and the intermediate layer. A lower space is provided between the layers, and the lower space, the through-hole, and the upper space are used as a liquid storage section including a sealed communication channel. The liquid storage part is filled with the said separation liquid coloring composition containing the said coloring liquid and the polar solvent which is not miscible with the said coloring liquid. The upper and lower spaces are provided with colored liquid passages communicating with each other through the through holes, and the colored liquid is caused to flow into and out of the display-side upper space by an electrowetting method with or without application of voltage to the colored liquid.
A colored image is displayed without transmitting light at the time of inflow, and light is transmitted at the time of outflow, and white display is performed by light scattering of the light scatterer, that is, display is performed by modulating the brightness of the passing light.

The device has a two-terminal structure in which an electrode is arranged on the upper layer and an electrode is arranged on the inner surface of the through hole, the two terminals are connected via a switch, and the switch is turned on / off to turn the display side The colored liquid is allowed to flow into the upper space to display a colored image, and the colored fluid is allowed to flow out of the upper space to switch to the white scattering screen. Alternatively, a three-terminal structure may be used instead of the two-terminal structure.
In the three-terminal structure, an upper electrode is provided on the upper surface or / and the lower surface of the upper space, a lower electrode is provided on the upper surface or / and the lower surface of the lower space, and a common electrode disposed along the inner surface of the through hole of the white scattering sheet is provided, An upper side power supply circuit and a lower side power supply circuit connected to the common electrode and the upper electrode, and connected to the common electrode and the lower electrode and provided with circuit opening / closing means, respectively. The circuit opening / closing means may be alternately opened / closed to switch the inflow / outflow of the colored liquid to / from the upper space.
With this three-terminal structure, the colored liquid flows into and out of the upper space by alternately opening and closing the upper power circuit and the lower power circuit. It can be carried out.

Regardless of the configuration of the device, a dielectric layer may be disposed on the side of the electrode in contact with the conductive colored liquid. The dielectric layer preferably contains, for example, parylene or alumina oxide, and the layer thickness is preferably about 1 to 0.1 μm.
In addition, when a water repellent film that becomes a hydrophilic layer is laminated on the surface of the dielectric layer and the water repellent film is in contact with the colored liquid, the conductive colored liquid can be moved at high speed or the surface area can be increased or decreased. Therefore, it can be suitable as a moving image display.

  In the device, the display space is partitioned by a partition wall for each pixel, and the colored liquid used for each pixel is any one of R, G, and B, or any one of C, M, Y, and K The liquid is a liquid, and a color liquid is introduced and spreads in the display space, thereby displaying a full color image and moving the ionic liquid at a high speed to display a full color moving image.

  The device may be configured to form a color filter of any one of R, G, B or C, M, Y, K before and after light passes through the display space, and further perform light modulation. it can.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not restrict | limited to the following Example at all. In the following examples, g and% are in terms of mass.

(Synthesis Method of Polyimide Resin (X) Synthesis of Polyester (A))
In a reaction flask equipped with a thermometer, stirrer, nitrogen inlet, reflux tube and water separator, 300.0 g of xylene (made by Junsei Chemical), 300.0 g of 12-hydroxystearic acid (made by Junsei Chemical) and tetrabutyl A titanate (manufactured by Tokyo Chemical Industry) (0.1 g) was charged, and the temperature was raised to 160 ° C. over 4 hours under a nitrogen stream.
Furthermore, it heated at 160 degreeC for 4 hours, the water produced | generated during the heating reaction was distilled off, and the xylene solution of polyester (A) was obtained. The xylene solution of polyester (A) had a solid content concentration of 48% by weight, a number average molecular weight of 1100, and an acid value of 25 mg KOH / g.

  Next, in a flask equipped with a stirrer, a reflux condenser, a nitrogen blowing tube, and a thermometer, 8 g of polyethyleneimine (Epomin SP-006, manufactured by Nippon Shokubai Chemical Industry Co., Ltd., average molecular weight of about 600), and the above 192 g of a xylene solution of polyester (A) was charged and reacted at 160 ° C. for 4 hours while stirring under a nitrogen stream. Volatiles were removed from the resulting reaction product under reduced pressure (5 mmHg, heated to 80 ° C.), the number average molecular weight was 1800, the acid value was 1 mgKOH / g, and the amine value was 60 mgKOH / g, a brown viscous 100 g of polyimide resin (X) which is a modified polyethyleneimine was obtained.

(Example 1 colored liquid)
Styrene / methacrylic acid (MAA) / acrylic acid (AA) = 87.7 / 8.1 / 4.2 (mass ratio), acid value = 93 mg KOH / g, weight average molecular weight = 7500, glass transition temperature: 107 ° C. 360 g of the resin (P), 1200 g of carbon black “# 995B” manufactured by Mitsubishi Chemical, and 600 g of diethylene glycol were charged into a 3 L pressure kneader and heated until the internal temperature of the kneader reached 60 ° C. When the internal temperature of the pressure kneader reached 60 ° C., kneading was started and kneading was continued for 30 minutes. This kneaded product was dried for 5 hours or more in a vacuum dryer at a container temperature of 150 ° C., and the solid content concentration was determined by mass change before and after drying and found to be 73%. Therefore, when this is compared with the solid content concentration at the time of charging and the change in mass before and after kneading is calculated, the mass of 97.8% at the time of charging is maintained.
55.15 g of the kneaded product taken out was added to an aqueous solution of 30 g of ion-exchanged water, 0.87 g of potassium hydroxide and 16.87 g of DEG, and after stirring and dispersing with a dispersion stirrer, under the following conditions, using a sand grinder manufactured by IMEX Co., Ltd. Dispersion was performed to obtain a pigment dispersion (A).
Sand grinder condition Vessel capacity: 800ml
Beads: φ2.5mm zirconia beads 640g
Rotational speed: 2500 r. p. m.
Jacket temperature: 10 ° C
Dispersion time: 3 hours The obtained pigment dispersion (A) was filtered and washed with a normal method, then dried in a vacuum dryer at a container temperature of 150 ° C. for 5 hours or more and pulverized to obtain a colorant (A ) 50 g was obtained.

  Next, 10 g of the colorant (A) obtained in a 250 ml polyethylene bottle, 150 g of 3 mm glass beads, and 32.5 g of xylene were added and dispersed for 120 minutes with a paint conditioner. Then, 67.5 g of xylene was further added, and 5 Dispersion was carried out for minutes to obtain a colored liquid (A). The obtained colored liquid (A) was a stable liquid excellent in fluidity.

(Example 2 colored liquid)
Planetary mixer “PLM-V-50V” (stock) of 1500 g of resin (P) used in Example 1, 5000 g of carbon black # “995B” manufactured by Mitsubishi Chemical, 428 g of 8N potassium hydroxide aqueous solution and 3000 g of diethylene glycol The jacket was heated to 60 ° C. and stirred at a rotation speed of 60 rotations / minute and a revolution speed of 20 rotations / minute.
This kneaded product was dried for 5 hours or more in a vacuum dryer at a container temperature of 150 ° C., and the solid content concentration was determined by mass change before and after drying, and found to be 68.2%. Therefore, when this is compared with the solid content concentration at the time of charging and the mass change before and after kneading is calculated, the mass of 96.0% at the time of charging is maintained.
After kneading for 3.5 hours, ion-exchanged water heated to 60 ° C. was gradually added. Finally, 15000 g of ion-exchanged water was added to obtain a pigment dispersion C having a carbon black concentration of about 20%. The obtained pigment dispersion C was filtered and washed with ordinary methods, then dried in a vacuum dryer at a container temperature of 150 ° C. for 5 hours or more and pulverized to obtain 50 g of a colorant (B).

  The colorant (B) was dispersed in xylene in the same manner as in Example 1 to obtain a colored liquid (B). The obtained colored liquid (B) was a stable liquid excellent in fluidity.

(Example 3 colored liquid and separated liquid colored composition)
The colorant (B) obtained in Example 2 and decalin were charged into 100 ml of polyvin so that the total amount was 30 g at the ratio shown in Table 1. Further, 180 g of 0.5 mm zirconia beads were further charged and dispersed for 120 minutes by a paint conditioner to obtain a colored liquid (C). The obtained colored liquid (C) was a stable liquid excellent in fluidity.

A 10 ml vial was charged with 5 g of ion-exchanged water and 0.5 g of the colored liquid (C) to obtain a separated liquid colored composition (C1). This was stirred 100 times by hand, and the separability after 24 hours was visually confirmed.
In order to confirm the same separability, instead of ion-exchanged water, ethylene glycol described in JP-A-10-39800 was used, and 10 g vial was charged with 5 g ethylene glycol and 0.5 g colored liquid (C). To obtain a separated liquid coloring composition (C2). This was stirred 100 times by hand, and the separability between ion-exchanged water or ethylene glycol and the colored liquid (C) after 24 hours was visually confirmed.
The state of separation was evaluated in five stages according to the following criteria. The results are shown in Table 1.

5: Coloring to ion-exchanged water or ethylene glycol is not observed, and the interface is clear and separated into two layers.
4: Coloring to ion exchange water or ethylene glycol is not observed, and the interface is slightly unclear.
3: Coloring to ion-exchanged water or ethylene glycol is observed, and the interface is slightly unclear.
2: Coloring to ion exchange water or ethylene glycol is observed, and the interface is unclear.
1: Not separated into two layers.

(Examples 4 to 6 colored liquid and separated liquid colored composition))
100 ml of the colorant, polyimide resin (X), and decalin to be used are those shown in Table 1 and ratios (in the table, (%) indicates mass (%)) and the total amount is 30 g. The colored liquids (D) to (F) were obtained in the same manner as in Example 3 except that the polybins were charged. All were stable liquids excellent in fluidity.
The separation liquid coloring compositions (D1) to (F1) and (D2) to (F2) were obtained in the same manner as in Example 3, and the separability was visually confirmed. The results are shown in Table 1.

  From the results of Table 1, the separated liquid colored compositions (C1) to (F1) obtained in Examples 3 to 6 are separated from ion-exchanged water, and the separated liquid colored compositions (C2) to (F2). ) Was excellent in separability from ethylene glycol. In particular, the separation liquid coloring compositions (C2) to (F2) become more separable by adding the polyimide resin (X) functioning as a dispersing agent, and the separability becomes better as the addition amount is increased. The result was obtained. (From the results of Examples 3, 4, and 5)

(Comparative Example 1)
50 g of the resin used in Example 1 was dissolved in 50 g of methyl ethyl ketone, 100 g of ion exchange water and 4.7 g of potassium hydroxide were further added, and the mixture was stirred well to prepare a resin solution (H1). Methyl ethyl ketone was removed from the resin solution (H1) under reduced pressure conditions of a water bath temperature of 45 ° C. and 40 hPa to obtain 110.7 g of a resin-dissolved alkaline aqueous solution (H1). Water was added to the obtained resin-dissolved alkaline aqueous solution (H1) and stirred to obtain a resin aqueous solution (H1) having a total mass of 155.6 g.
24.5 g of aqueous resin solution (H1), 14.2 g of ion exchange water, 32.6 g of diethylene glycol, and 31.5 g of carbon black “# 995B” manufactured by Mitsubishi Chemical Co., Ltd. were mixed and stirred in the same manner as in Example 1 Dispersion was carried out with a company-made sand grinder to obtain a pigment dispersion (H1).
The obtained pigment dispersion (H1) was filtered and washed with ordinary methods, then dried in a vacuum dryer at a container temperature of 150 ° C. for 5 hours or more and pulverized to obtain 35 g of a colorant (H1). .

  Next, 10 g of the colorant (H1) obtained in a 250 ml polyethylene bottle, 150 g of 3 mm glass beads, and 32.5 g of xylene were added and dispersed for 120 minutes with a paint conditioner. Then, 67.5 g of xylene was further added, and 5 Dispersion was carried out for minutes to obtain a colored liquid (H1). The resulting colored liquid (H1) was an unstable dispersion having poor fluidity.

The perspective view which showed an example of the structure of a planetary mixer. A partially enlarged view of the planetary mixer. Explanatory drawing which showed the locus | trajectory of the stirring blade in a planetary mixer.

1 ... Stirring tank,
4, 5 ... stirring blade 6 ... rotor

Claims (9)

It is used for a light modulation device that modulates color or brightness by moving or deforming a liquid by an external electric field, and is a colored liquid containing a nonpolar solvent and a colorant, wherein the colorant is at least a resin, A mixture containing a water-soluble organic solvent and a pigment is charged using a closed kneader equipped with a sealable stirring tank and a uniaxial or multiaxial stirring blade, and the mass of the mixture during kneading is charged before kneading. A coloring liquid obtained by kneading so as to be maintained in a range of 90% by mass or more based on the amount. The colored liquid according to claim 1, wherein the mixture (1) has a solid content ratio of 50% by mass or more, and (2) contains the water-soluble organic solvent in a mass ratio of 1/3 or more of the pigment. The colored liquid according to claim 1 or 2, wherein the kneader is a planetary mixer. The colored liquid according to claim 1, wherein the pigment is carbon black. The colored liquid according to claim 1, wherein the light modulation method is an electrowetting method or an electrofluidic method. A separated liquid coloring composition comprising the colored liquid according to claim 1 and a polar solvent that is immiscible with the colored liquid. The separated liquid coloring composition according to claim 6, wherein the coloring liquid contains a polyimide resin. The coloring liquid according to any one of claims 1 to 5, as a colorant for generating an image in a light modulation type device that modulates color or brightness by moving or deforming the liquid by an external electric field use. Use according to claim 8, wherein the modulation scheme is an electrowetting scheme.

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