Method for producing pigment composition, pigment composition, and coloring composition for color filters

Abstract

To provide a method for producing a pigment composition that enables stable pigment dispersion and allows the preparation of a coloring composition capable of forming an image such as a pixel with a high contrast ratio, and a pigment composition produced by the production method.SOLUTION: The present invention provides a method for producing a pigment composition that includes the step of mixing a pigment component containing an organic pigment such as a quinophthalone-based pigment and a pigment sulfonic acid derivative, and a silane coupling agent with an amino group, in the presence of water. The present invention also provides a pigment composition produced by the production method.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing a pigment composition, a pigment composition, and a coloring composition for color filters. [Background technology]

[0002] In a typical color liquid crystal display device, a transparent electrode for driving the liquid crystal is formed on a color filter by vapor deposition or sputtering, and an alignment film for aligning the liquid crystal in a certain direction is further formed on top of the transparent electrode. In order to improve the performance of the transparent electrode and the alignment film, it is necessary to treat the color filter at a high temperature of 200°C or higher, preferably 230°C or higher, in the manufacturing process for forming the color filter. For this reason, it is mainstream to form color filters using a pigment with excellent light resistance and heat resistance, and using a colorant in which such a pigment is dispersed by a method called a pigment dispersion method.

[0003] However, color filters formed using dispersed pigments have problems such as the scattering of light by the pigments, which disrupts the degree of polarization controlled by the liquid crystals. In other words, when blocking light (OFF state), light leaks, and when transmitting light (ON state), the transmitted light is attenuated, which can reduce the brightness ratio (contrast ratio) on the display device in the ON and OFF states.

[0004] In recent years, in order to realize high brightness and high contrast of color filters, finely-processed pigments are often contained in filter segments. A typical pigment is a mixture of primary particles, which are obtained by pigmenting crude particles having a particle diameter of 10 to 100 μm obtained by chemical reaction, and secondary particles, which are aggregates of the primary particles. Even if such pigments are finely-processed by various fine processing methods, the finely-processed pigments generally tend to aggregate. Moreover, primary particles and secondary particles of pigments that are too fine tend to form huge lumpy pigment solids. Furthermore, even if finely-processed pigments are dispersed in a carrier containing a resin or the like and stabilized as close as possible to primary particles, it has been difficult to obtain pigment compositions or coloring compositions with good dispersion stability.

[0005] For example, CI Pigment Yellow 138 is a pigment that has high brightness and good light resistance, but has poor dispersion stability. For this reason, it is difficult to achieve the original vivid color development, and it has problems such as being prone to sedimentation and reduced fluidity due to its tendency to aggregate.

[0006] In order to solve such problems, for example, pigment compositions have been proposed that have improved dispersibility by combining pigments with pigment dispersants or pigment derivatives selected according to the molecular structure and surface properties of the pigment (Patent Documents 1 and 2). Surface-treated organic pigment particles have also been proposed in which the particle surfaces of organic pigments are coated with a metal-containing gel layer (Patent Document 3). Furthermore, a pigment dispersion composition for color filters containing a pigment, a coupling agent, an acrylic copolymer, and a solvent has been proposed (Patent Document 4). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2002-105351 A [Patent Document 2] JP 2003-183533 A [Patent Document 3] JP 2011-57772 A [Patent Document 4] JP 2003-64293 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, even with the pigment compositions proposed in Patent Documents 1 to 4, it is difficult to prepare a coloring composition having excellent pigment dispersion stability, and there is room for further improvement. In addition, the contrast ratio of a color filter formed using the obtained coloring composition is not necessarily sufficient, and further improvement is required.

[0009] The present invention has been made in consideration of the problems associated with such conventional techniques, and an object of the present invention is to provide a method for producing a pigment composition capable of preparing a coloring composition which has excellent pigment dispersion stability and is capable of forming images, such as pixels, having a high contrast ratio.

[0010] Another object of the present invention is to provide a pigment composition produced by the above-mentioned production method, which is excellent in pigment dispersion stability and can be used to prepare a coloring composition capable of forming an image of a pixel with a high contrast ratio, etc. A further object of the present invention is to provide a coloring composition for color filters obtained by using the above-mentioned pigment composition, which is excellent in pigment dispersion stability and can form a pixel with a high contrast ratio. [Means for solving the problem]

[0011] That is, according to the present invention, there is provided a method for producing a pigment composition as described below. [1] A method for producing a pigment composition, comprising the step of mixing a pigment component containing an organic pigment and a pigment sulfonic acid derivative with a silane coupling agent having an amino group in the presence of water. [2] The method for producing a pigment composition according to [1] above, wherein the organic pigment is a quinophthalone pigment. [3] The method for producing a pigment composition according to [1] or [2], wherein the pigment component and the silane coupling agent are mixed under conditions of pH 7 or less. [4] The method for producing a pigment composition according to any one of [1] to [3] above, wherein the amount of the silane coupling agent is 0.1 to 30 parts by mass per 100 parts by mass of the organic pigment. [5] The method for producing a pigment composition according to any one of [1] to [4], wherein the amount of the pigment sulfonic acid derivative is 1 to 30 parts by mass per 100 parts by mass of the organic pigment. [6] The method for producing a pigment composition according to any one of [1] to [5] above, wherein the silane coupling agent is at least one selected from the group consisting of N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and 3-aminopropyltrimethoxysilane.

[0012] According to the present invention, there is also provided a pigment composition as shown below. [7] A pigment composition produced by the production method according to any one of [1] to [6] above. [8] The pigment composition according to [7] above, which is for use in a color filter.

[0013] Furthermore, according to the present invention, there is provided a coloring composition for color filters as shown below. [9] A coloring composition for color filters, comprising the pigment composition according to [8] above. Effect of the Invention

[0014] According to the present invention, it is possible to provide a method for producing a pigment composition capable of preparing a coloring composition which has excellent pigment dispersion stability and is capable of forming an image such as a pixel having a high contrast ratio.

[0015] According to the present invention, it is also possible to provide a pigment composition produced by the above-mentioned production method, which is excellent in pigment dispersion stability and can be used to prepare a coloring composition capable of forming an image of a pixel with a high contrast ratio, etc. Furthermore, according to the present invention, it is also possible to provide a coloring composition for color filters, which is obtained by using the above-mentioned pigment composition, which is excellent in pigment dispersion stability and can form a pixel with a high contrast ratio. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] <Method of producing pigment composition> Hereinafter, the embodiment of the present invention will be described, but the present invention is not limited to the following embodiment. One embodiment of the method for producing a pigment composition of the present invention has a step of mixing a pigment component containing an organic pigment and a pigment sulfonic acid derivative with a silane coupling agent having an amino group in the presence of water. Hereinafter, the details of the method for producing a pigment composition of this embodiment will be described.

[0017] (Mixing process) The pigment composition of this embodiment (hereinafter, also simply referred to as the "production method") includes a step (mixing step) of mixing a pigment component containing an organic pigment and a pigment sulfonic acid derivative with a silane coupling agent having an amino group in the presence of water. The silane coupling agent having an amino group (hereinafter, also simply referred to as the "silane coupling agent") usually has an alkoxy group such as a methoxy group or an ethoxy group in its molecule in addition to an amino group. When the pigment component and the silane coupling agent are mixed in the presence of water, at least a part of the alkoxy group of the silane coupling agent that comes into contact with the water is hydrolyzed to form a silanol group (Si-OH), and a coupling agent having an amino group and a silanol group is generated. The coupling agent having an amino group and a silanol group (aminosilanol-based coupling agent) thus generated acts on the organic pigment or pigment sulfonic acid derivative in the pigment component, and it is considered that a pigment composition that is excellent in pigment dispersion stability and can prepare a coloring composition that can form an image such as a pixel with a high contrast ratio can be obtained.

[0018] The pigment component and the silane coupling agent are mixed in a liquid medium containing, for example, water. The liquid medium may contain a liquid medium other than water or various inorganic salts, etc., as necessary. As the liquid medium other than water, a water-soluble organic solvent can be used. Among them, it is preferable to use water as the liquid medium.

[0019] It is preferable to mix the pigment component and the silane coupling agent under conditions of pH 7 or less, more preferably under conditions of pH 5.5 or less, and particularly preferably under conditions of pH 1.5 to 4. It is considered that mixing the pigment component and the silane coupling agent in the neutral to acidic range, especially in the acidic range, moderately promotes hydrolysis of the alkoxy group of the silane coupling agent, and facilitates the formation of a silanol group (Si-OH). This further improves the dispersion stability of the pigment, and allows the formation of an image such as a pixel with a higher contrast ratio. The pH in this specification is a value measured under conditions of 25°C.

[0020] The dispersed organic pigment and pigment sulfonic acid derivative are mixed with the silane coupling agent at preferably 0 to 100° C., more preferably under heated conditions, and particularly preferably at 40 to 90° C. By mixing under heated conditions, the dispersion stability of the pigment is further improved, and the contrast ratio of the formed image, such as pixels, can be further increased.

[0021] After mixing the pigment component and the silane coupling agent, the mixture is filtered and washed, and if necessary, dried and pulverized to obtain the desired pigment composition. The drying method may be a method of heating to 80 to 120°C using a heat source installed in a dryer. The drying method may be either a batch method or a continuous method. As the dryer, a box dryer, a band dryer, a spray dryer, or the like may be used. As the pulverization method, a pulverization method using a mortar, a hammer mill, a disk mill, a pin mill, a jet mill, or the like may be used.

[0022] (Organic pigments) As the organic pigment, a conventionally known organic pigment can be used. As the organic pigment, for example, quinophthalone pigments, phthalocyanine pigments, diketopyrrolopyrrole pigments, anthraquinone pigments, azo pigments, quinacridone pigments, etc. can be mentioned. Among them, quinophthalone pigments, phthalocyanine pigments, and diketopyrrolopyrrole pigments are preferred because they can further improve the dispersion stability of the pigment and form images such as pixels with a higher contrast ratio.

[0023] The average primary particle diameter of the organic pigment is preferably 10 to 50 nm. By using an organic pigment whose average primary particle diameter is within the above range, the brightness and contrast ratio of the pixels of the obtained color filter or the like can be further improved. In this specification, the "average primary particle diameter" refers to the median diameter (D 50 ) When the average primary particle size of the organic pigment exceeds 50 nm, the brightness and contrast ratio may be somewhat lower. On the other hand, when the average primary particle size of the organic pigment is less than 10 nm, it may be somewhat difficult to disperse the pigment and it may be difficult to ensure the flowability of the coloring composition, so that the brightness and contrast ratio tend to be somewhat lower.

[0024] [Quinophthalone pigments] Examples of quinophthalone pigments include CI Pigment Yellow 138 and quinophthalone pigments having a phthalic anhydride group in which the hydrogen atom on the benzene ring is replaced with an alkyl group or a halogen atom. The more the number of halogen atoms substituted, the more preferable. The halogen atoms are preferably chlorine and bromine atoms from the viewpoint of ease of synthesis.

[0025] CI Pigment Yellow 138 can be produced by a conventionally known production method. For example, as described in "Industrial Organic Pigments (by W. Herbst and K. Hunger)", page 539, lines 1 to 9, CI Pigment Yellow 138 can be produced by reacting 1 mole of 8-aminoquinaldine with 2 moles of tetrachlorophthalic anhydride at 130 to 300°C.

[0026] (Pigment sulfonic acid derivatives) As the pigment sulfonate derivative (hereinafter also referred to as "pigment derivative"), an organic pigment sulfonate, a metal salt of an organic pigment sulfonate, an amine salt of an organic pigment sulfonate, etc. can be used. The pigment derivative can be produced, for example, by introducing a sulfonic acid group or the like into an organic pigment. Specific examples of the organic pigment include the organic pigments described above. Sulfonic acid derivatives such as quinophthalone pigments, phthalocyanine pigments, and diketopyrrolopyrrole pigments are preferred because they further improve the dispersion stability of the pigment and can form images such as pixels with a higher contrast ratio.

[0027] The amount of the pigment acid derivative relative to 100 parts by mass of the organic pigment is preferably from 1 to 30 parts by mass, more preferably from 5 to 30 parts by mass, and particularly preferably from 5 to 20 parts by mass.

[0028] [Quinophthalone pigment sulfonic acid derivatives] Examples of quinophthalone pigment sulfonic acid derivatives (hereinafter also referred to as "quinophthalone pigment derivatives") include sulfonated quinophthalone pigments, metal salts of sulfonated quinophthalone pigments, and amine salts of sulfonated quinophthalone pigments. Quinophthalone pigment derivatives are, for example, represented by the following general formula (1).

[0029] TIFF2025002309000001.tif59170 (In the general formula (1), X's each independently represent a halogen atom, m1 and m2 each independently represent a number from 0 to 4, M represents a hydrogen atom, a metal atom, an amino group, an organic amino group, or a quaternary ammonium base, and n represents a number from 1 to 2.)

[0030] Examples of metals constituting the metal salt of sulfonated quinophthalone pigment include sodium, potassium, calcium, barium, iron, magnesium, aluminum, nickel, cobalt, and strontium. Among them, aluminum salt of sulfonated quinophthalone pigment is preferred. Aluminum salt of sulfonated quinophthalone pigment has good dispersibility as a pigment dispersant and can improve isolation during production. Furthermore, it is possible to obtain a composition that has low viscosity and excellent flow characteristics and viscosity stability over time.

[0031] Examples of amines constituting the amine salt of the sulfonated quinophthalone pigment include lower amines such as ammonia, dimethylamine, trimethylamine, diethylamine, triethylamine, hydroxyethylamine, dihydroxyethylamine, 2-ethylhexylamine, N,N-dimethylaminopropylamine, N,N-diethylaminopropylamine, and N,N-dibutylaminopropylamine; long-chain alkylamines such as laurylamine, oleylamine, palmitylamine, stearylamine, and dimethyllaurylamine; and quaternary ammonium ions having a long-chain alkyl group such as laurylammonium, stearylammonium, lauryltrimethylammonium, dilauryldimethylammonium, stearyltrimethylammonium, and distearyldimethylammonium. Among these, when a salt with a quaternary ammonium ion having an alkyl group with 12 or more carbon atoms such as laurylammonium or stearylammonium is used, a coloring composition having excellent dispersion stability and particularly high storage stability can be obtained.

[0032] (Silane coupling agent having an amino group) As the silane coupling agent having an amino group (silane coupling agent), a conventionally known compound can be used. As the commercially available silane coupling agent, the following trade names can be mentioned: KBM-602, KBM-603, KBM-903, KBE-903, KBE-9103P, KBM-573, KBM-575, and KBM-6803 (all manufactured by Shin-Etsu Chemical Co., Ltd.).

[0033] The silane coupling agent is preferably at least one selected from the group consisting of N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and 3-aminopropyltrimethoxysilane. The amount of the silane coupling agent relative to 100 parts by mass of the organic pigment is preferably 0.1 to 30 parts by mass, and more preferably 1 to 20 parts by mass.

[0034] (Refining process) By subjecting the organic pigment to a micronization treatment in advance to reduce the primary particle size, the brightness and contrast ratio of the resulting color filter can be further increased. Micronization treatment methods include a method of mechanically pulverizing the pigment (grinding method), a method of dissolving the pigment in a good solvent and then putting it into a poor solvent to precipitate the pigment (precipitation method), and a method of producing a pigment with a desired primary particle size (synthetic precipitation method).

[0035] The grinding method is a method in which a pigment is mechanically kneaded (so-called "solvent salt milling process") together with a grinding agent such as a water-soluble inorganic salt and a water-soluble organic solvent that does not dissolve the grinding agent using a ball mill, sand mill, kneader, or the like, and then the grinding agent and the water-soluble organic solvent are washed away with water and dried. Note that, since the pigment may undergo crystal growth during the solvent salt milling, it is preferable to add a solid resin, a dispersing aid, or the like to the water-soluble organic solvent to suppress the crystal growth of the pigment.

[0036] The manufacturing method of this embodiment preferably further includes a step of subjecting the organic pigment to a solvent salt milling treatment (solvent salt milling treatment step) prior to the above-mentioned mixing step. The solvent salt milling treatment step is a step of placing an organic pigment, a grinding agent, a water-soluble organic solvent, etc. in a kneader and grinding them by kneading. As the kneader, a kneader, a mixer, etc. can be used. As the grinding agent, a water-soluble inorganic salt such as sodium chloride, potassium chloride, sodium sulfate, etc. can be used. The average particle size of the inorganic salt is preferably 0.3 to 70 μm. The amount of the inorganic salt used is preferably 3 to 30 parts by mass, more preferably 7 to 30 parts by mass, and particularly preferably 10 to 30 parts by mass, per part by mass of the mixture containing the organic pigment.

[0037] As the water-soluble organic solvent, diethylene glycol, glycerin, ethylene glycol, propylene glycol, liquid polyethylene glycol, liquid polypropylene glycol, 2-(methoxymethoxy)ethanol, 2-butoxyethanol, 2-isopentyloxy)ethanol, 2-(hexyloxy)ethanol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol, etc. can be used. The amount of the water-soluble organic solvent used is preferably 0.01 to 5 parts by mass relative to 1 part by mass of the mixture containing the organic pigment. When performing the solvent salt milling treatment, other organic pigments or pigment derivatives may be further used for the purpose of color matching.

[0038] The inorganic salt and the water-soluble organic solvent may be charged in their entirety from the start of the solvent salt milling treatment, or may be charged in portions. The temperature during the solvent salt milling treatment is preferably 150° C. or lower, and more preferably 50 to 120° C. The time for the solvent salt milling treatment is preferably 3 to 36 hours, and more preferably 3 to 24 hours.

[0039] After the solvent salt milling process, the grinding agent such as inorganic salt and the water-soluble organic solvent are removed by washing with water or hot water. The obtained solid matter may then be dried and pulverized. The quinacridone pigment derivative may be added after removing the grinding agent and the water-soluble organic solvent. Considering that the product is to be used as a material for manufacturing pixel parts of color filters, it is preferable to wash the filtrate until the specific conductivity is 50 μS / cm or less, and more preferably 20 μS / cm or less.

[0040] <Pigment composition> One embodiment of the pigment composition of the present invention is produced by the above-mentioned method for producing a pigment composition. Since the pigment composition of this embodiment is produced by the above-mentioned method, it is possible to prepare a coloring composition that has excellent pigment dispersion stability and can form an image such as a pixel with a high contrast ratio. Therefore, the pigment composition of this embodiment is suitable as a material for producing a color filter, that is, as a composition for a color filter (pigment composition for a color filter).

[0041] In addition, by producing the pigment by the above-mentioned production method, as described above, at least a part of the alkoxy group of the silane coupling agent is hydrolyzed to form a silanol group (Si-OH), and a coupling agent having an amino group and a silanol group is produced. Then, it is considered that the coupling agent having the amino group and the silanol group produced (aminosilanol-based coupling agent) acts with the organic pigment or pigment sulfonic acid derivative in the pigment component. Furthermore, it is presumed that the surface state and dispersion state of the organic pigment, and the interaction state of each component, etc. change, and a pigment composition showing the desired characteristics is obtained. In addition, the generation of the silanol group (Si-OH) by the hydrolysis of the alkoxy group of the silane coupling agent can be confirmed by, for example, NMR or GCMS. However, it is substantially difficult or impossible to analyze and confirm the amount and existence state of the aminosilanol-based coupling agent in the obtained pigment composition, the surface state and dispersion state of the organic pigment, and the interaction state of each component.

[0042] <Coloring composition for color filters> One embodiment of the coloring composition for color filters (hereinafter also referred to as "coloring composition for CF") of the present invention contains the above-mentioned pigment composition. Therefore, the coloring composition for CF of this embodiment has excellent dispersion stability of the organic pigment and can form pixels with a high contrast ratio.

[0043] The CF coloring composition can further contain various components contained in conventionally known coloring compositions for forming pixels for CF. Specifically, the CF coloring composition can contain a polymer dispersant for dispersing the pigment, a binder resin, various organic solvents, and the like.

[0044] (Polymer dispersant) As the polymer dispersant, a conventionally known polymer for dispersing organic pigments can be used. The content of the polymer dispersant is preferably 0.5 to 10 parts by mass (as non-volatile content) per 100 parts by mass of the organic pigment.

[0045] The polymer is preferably an acrylic copolymer having a structural unit derived from monomer A that adsorbs to the surface of the organic pigment. As monomer A, a (meth)acrylic acid ester monomer having a hydrocarbon ring structure, such as benzyl (meth)acrylate, 1-naphthyl (meth)acrylate, 2-naphthyl (meth)acrylate, cyclopentyl (meth)acrylate, or cyclohexyl (meth)acrylate, is preferred. In addition, the acrylic copolymer preferably further has a structural unit derived from monomer B that adsorbs to the surface of the pigment and exerts a dispersion stabilizing effect. As monomer B, a (meth)acrylic acid monomer or a (meth)acrylic acid ester monomer such as glycidyl (meth)acrylate or acid phosphooxyethyl methacrylate is preferred.

[0046] The acrylic copolymer may further have a constituent unit derived from a monomer (other monomer) other than the monomer A and the monomer B. Examples of the other monomer include a (meth)acrylic acid ester, a monomer other than a (meth)acrylic acid ester, and a copolymerizable unsaturated carboxylic acid.

[0047] Examples of (meth)acrylic acid esters include (meth)acrylic acid esters having an alkyl group such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tertiary butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, dodecyl (meth)acrylate [lauryl (meth)acrylate], and octadecyl (meth)acrylate [stearyl (meth)acrylate]; (meth)acrylic acid esters having an alicyclic group such as cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, and dicyclopentanyl (meth)acrylate; methoxytriethylene glycol (meth)acrylate, methoxypolyethylene glycol #400 (meth)acrylate, and the like. (meth)acrylic acid esters containing an ether group such as acrylate, methoxydipropylene glycol (meth)acrylate, methoxytripropylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, ethyl carbitol (meth)acrylate, 2-ethylhexyl carbitol (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, p-nonylphenoxyethyl (meth)acrylate, and p-nonylphenoxypolyethylene glycol (meth)acrylate; (meth)acrylic acid esters containing an aromatic ring such as benzyl (meth)acrylate; (meth)acrylic acid esters containing an epoxy group such as glycidyl (meth)acrylate, allyl glycidyl ether, and 4-hydroxybutyl (meth)acrylate glycidyl ether;Examples of (meth)acrylic acid esters having a phosphoric acid group include acid phosphooxyethyl methacrylate, acid phosphooxypropyl methacrylate, acid phosphooxypolyoxyethylene glycol monomethacrylate, and acid phosphooxypolyoxypropylene glycol monomethacrylate, ethylene glycol methacrylate phosphate, propylene glycol methacrylate phosphate, ethylene glycol acrylate phosphate, and propylene glycol acrylate phosphate. Commercially available (meth)acrylic acid esters having a phosphoric acid group include, under the trade names below, Phosmer M, Phosmer CL, Phosmer PE, and Phosmer MH (all manufactured by Unichemical Co., Ltd.); Light Ester P-1M (all manufactured by Kyoeisha Chemical Co., Ltd.); JAMP-514 (all manufactured by Johoku Chemical Co., Ltd.); KAYAMER PM-2 and KAYAMER PM-21 (all manufactured by Nippon Kayaku Co., Ltd.); and the like.

[0048] Examples of monomers other than (meth)acrylic acid esters include vinyl esters such as vinyl acetate, vinyl propionate, and tertiary vinyl carboxylate; heterocyclic vinyl compounds such as vinyl pyrrolidone; halogenated olefins such as vinyl chloride, vinylidene chloride, and vinylidene fluoride, and cyano group-containing monomers such as acrylonitrile and methacrylonitrile; vinyl ethers such as ethyl vinyl ether and isobutyl vinyl ether; vinyl ketones such as methyl vinyl ketone; α-olefins such as ethylene and propylene; dienes such as butadiene and isoprene; and styrene-based monomers such as styrene, vinyl toluene, α-methylstyrene, dimethylstyrene, and tertiary butylstyrene.

[0049] Examples of copolymerizable unsaturated carboxylic acids include monocarboxylic acids and anhydrides thereof, such as crotonic acid, isocrotonic acid, 2-(meth)acryloyloxyethyl succinic acid, 2-(meth)acryloyloxyhexahydrophthalic acid, and 2-(meth)acryloyloxyethyl glutarate; dicarboxylic acids and anhydrides thereof, such as maleic acid, fumaric acid, and itaconic acid; and monoalkyl esters of dicarboxylic acids, such as monomethyl maleic acid, monoethyl maleic acid, monobutyl maleic acid, monooctyl maleic acid, monomethyl fumaric acid, monoethyl fumaric acid, monobutyl fumaric acid, monooctyl fumaric acid, monomethyl itaconic acid, monoethyl itaconic acid, monobutyl itaconic acid, and monooctyl itaconic acid.

[0050] The organic pigment is preferably coated with a polymer used as a polymer dispersant. Methods for coating the organic pigment with a polymer include, for example, a method of adding a polymer to a pigment composition and precipitating it; a method of adding an emulsion of a polymer to a pigment composition; a method of kneading and grinding the organic pigment together with a polymer; and the like. In order to effectively suppress the crystal growth of the organic pigment during the above-mentioned solvent salt milling treatment, it is preferable to utilize the crystal growth suppressing effect of the pigment derivative. For this reason, it is preferable that the polymer used as the polymer dispersant does not inhibit the adsorption of the pigment derivative to the organic pigment. After the suppression of crystal growth is completed, the organic pigment and the pigment derivative may be coated with a polymer.

[0051] By using the coloring composition for CF of this embodiment, a pixel portion of a color filter, particularly a pixel having a high contrast ratio, can be formed according to a conventionally known method such as a pigment dispersion method. EXAMPLES

[0052] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the examples and comparative examples, "parts" and "%" are by mass unless otherwise specified.

[0053] <Production of pigment sulfonic acid derivatives> (Production Example 1) Thirty parts of CI Pigment Yellow 138 (product name "Paliotol Yellow K0960HD", manufactured by BASF) were dissolved in 300 parts of 101% sulfuric acid, and the mixture was stirred at 70°C for 8 hours to carry out a sulfonation reaction. The reaction solution was poured into 3,000 parts of ice water, and the precipitate was obtained by filtration. The resulting precipitate was washed with water to obtain 27 parts of a press cake of a pigment sulfonic acid derivative (based on non-volatile content).

[0054] <Production of Pigment Composition> (Production Example 2) CI Pigment Yellow 138 (product name "Paliotol Yellow K0960HD, manufactured by BASF) 100 parts, sodium chloride 1,000 parts, and diethylene glycol 250 parts were put into a stainless steel kneader (manufactured by Inoue Seisakusho, 5 L) and kneaded at 60 ° C for 7 hours to obtain a kneaded product by salt milling. The kneaded product obtained was put into 3 L of warm water, heated to 70 ° C and stirred for 1 hour to obtain a slurry, and then filtered and washed with water repeatedly to remove sodium chloride and diethylene glycol, to obtain a press cake. The obtained press cake and 6 parts of the press cake of the pigment sulfonic acid derivative (in terms of non-volatile content) were peptized in 3 L of water, heated to 70 ° C, and then adjusted to pH 2 to obtain a slurry. Meanwhile, 10 parts of a silane coupling agent having an amino group (N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, trade name "KBM-603", manufactured by Shin-Etsu Chemical Co., Ltd.) were added to 0.2 L of water and dissolved by stirring for 30 minutes to obtain an aqueous solution. The obtained aqueous solution was added to the slurry, and the mixture was stirred for 1 hour at 70° C. After repeated filtration and washing with water, the mixture was dried at 80° C. for one day to obtain 110 parts of a pigment composition (A-1).

[0055] (Production Example 3) Except for changing the treatment temperature after the addition of the silane coupling agent to 50° C., the same procedure as in Production Example 2 was carried out to obtain 110 parts of a pigment composition (A-2).

[0056] (Production Example 4) Except for changing the treatment temperature after the addition of the silane coupling agent to 90° C., the same procedure as in Production Example 2 was carried out to obtain 110 parts of a pigment composition (A-3).

[0057] (Production Example 5) Except for adjusting the pH to 12 after the addition of the silane coupling agent, the same procedure as in Production Example 2 was carried out to obtain 110 parts of a pigment composition (A-4).

[0058] (Production Example 6) A pigment composition (A-5) (100 parts) was obtained in the same manner as in Production Example 2 described above, except that the aqueous solution of the silane coupling agent was not added.

[0059] Details of Production Examples 2 to 6 are shown in Table 1.

[0060] TIFF2025002309000002.tif57170

[0061] <Preparation of Coloring Composition (Pigment Dispersion)> Example 1 The components shown below were mixed and stirred until uniform, and then dispersed for 3 hours using a paint conditioner and zirconia beads with a diameter of 0.5 mm to obtain a dispersion. 24 parts of propylene glycol-1-monomethyl ether-2-acetate were added to 96 parts of the dispersion filtered through a filter. After dispersing for 3 hours using a paint conditioner and zirconia beads with a diameter of 0.1 mm, the mixture was filtered to obtain a colored composition (DA-1). Pigment composition (A-1): 15.0 parts Dispersant solution (product name "BYK LPN-6919", manufactured by BYK-Chemie): 10.0 parts Binder resin solution (product name "SPC-2000", manufactured by Showa Denko): 17.1 parts Propylene glycol-1-monomethyl ether-2-acetate: 57.9 parts

[0062] (Examples 2 to 4, Comparative Example 2) Colored compositions (DA-2) to (DA-4) and (DA-6) were obtained in the same manner as in Example 1 above, except that the types of pigment compositions shown in Table 2 were used.

[0063] Comparative Example 1 The components shown below were mixed and stirred until uniform, and then dispersed for 3 hours using a paint conditioner and zirconia beads with a diameter of 0.5 mm to obtain a dispersion. 24 parts of propylene glycol-1-monomethyl ether-2-acetate were added to 96 parts of the dispersion filtered through a filter. After dispersing for 3 hours using a paint conditioner and zirconia beads with a diameter of 0.1 mm, the mixture was filtered to obtain a colored composition (DA-5). Pigment composition (A-5): 13.7 parts Silane coupling agent having an amino group (N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, product name "KBM-603", manufactured by Shin-Etsu Chemical Co., Ltd.): 1.3 parts Dispersant solution (product name "BYK LPN-6919", manufactured by BYK-Chemie): 10.0 parts Binder resin solution (product name "SPC-2000", manufactured by Showa Denko): 17.1 parts Propylene glycol-1-monomethyl ether-2-acetate: 57.9 parts

[0064] <Evaluation> (Contrast ratio) The coloring composition was applied to a glass substrate using a spinner, dried at 90°C for 2 minutes, and then heated at 230°C for 30 minutes to form a coating film. The brightness and darkness of three coating films formed by changing the spinner speed were measured using a contrast meter (manufactured by Tsubosaka Electric Co., Ltd.), and the contrast ratio (brightness / darkness) was calculated. In addition, the chromaticity x of the coating film was measured using a spectrophotometer (product name "U-3310", manufactured by Hitachi, Ltd.). The chromaticity x and the contrast ratio were plotted on a graph to create an approximate straight line, and the contrast ratio value at chromaticity x = 0.430 was read. Then, the relative values ​​(%) were calculated, with the contrast ratio value of the coating film formed with the coloring composition of Comparative Example 1 taken as 100%. The results are shown in Table 2.

[0065] (Viscosity evaluation (dispersion stability)) Using an E-type viscometer, the viscosity (mPa s) of the colored composition immediately after preparation (initial) and after standing at 45°C for one week were measured. The measurement conditions were temperature: room temperature (25°C) and rotor rotation speed: 50 rpm. The results are shown in Table 2.

[0066] TIFF2025002309000003.tif70170 [Industrial Applicability]

[0067] The pigment composition of the present invention is useful as a material for obtaining a coloring composition for producing a color filter used in solid-state imaging devices such as color liquid crystal displays, C-MOS (Complementary Metal Oxide Semiconductors), and CCDs (Charge Coupled Devices).

Claims

1. A method for producing a pigment composition, comprising the step of mixing a pigment component containing an organic pigment and a pigment sulfonic acid derivative with a silane coupling agent having an amino group in the presence of water.

2. 2. The method for producing a pigment composition according to claim 1, wherein the organic pigment is a quinophthalone pigment.

3. The method for producing a pigment composition according to claim 1 , wherein the pigment component and the silane coupling agent are mixed under conditions of pH 7 or less.

4. 2. The method for producing a pigment composition according to claim 1, wherein the amount of the silane coupling agent is 0.1 to 30 parts by mass based on 100 parts by mass of the organic pigment.

5. 2. The method for producing a pigment composition according to claim 1, wherein the amount of the pigment sulfonic acid derivative is 1 to 30 parts by mass based on 100 parts by mass of the organic pigment.

6. 2. The method for producing a pigment composition according to claim 1, wherein the silane coupling agent is at least one selected from the group consisting of N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and 3-aminopropyltrimethoxysilane.

7. A pigment composition produced by the method according to any one of claims 1 to 6.

8. The pigment composition according to claim 7, which is for use in a color filter.

9. A coloring composition for color filters, comprising the pigment composition according to claim 8 .

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