Red coloring composition for color filter and method for producing the same, red coloring resist composition for color filter, color filter, and display device

Abstract

The present invention provides a method for producing a red coloring composition for color filters that suppresses sublimation products generated by organic pigments and produces a color filter with excellent contrast and brightness. The method includes a micronization step of salt-milling a diketopyrrolopyrrole pigment, a resin, and a sulfonate of a diketopyrrolopyrrole compound to obtain a micronized pigment, and an ink grinding step of grinding a mixture containing the micronized pigment and a sulfonate of a compound having an azo group and a naphthol skeleton; the resin having a maleimide skeleton and a sulfonic acid group.

Description

Technical Field

[0001] The present invention relates to a method for producing a red coloring composition for color filters (manufacturing method), a red coloring composition for color filters, a red coloring resist composition for color filters, a color filter, and a display device. Background Art

[0002] An essential technology for achieving high image quality in LCD televisions is the formation of high-definition color filters. Color filters include those with two or more fine stripes of different hues arranged in parallel on the surface of a transparent substrate such as glass, and those with fine pixels arranged in a fixed pattern vertically and horizontally.

[0003] Pixels are tiny, ranging from tens to hundreds of micrometers in size, but must be neatly arranged in a predetermined order for each hue. Furthermore, pixels of each hue are required to have basic performance characteristics such as high color purity and visible light transmittance, as well as high contrast.

[0004] As the applications of liquid crystal display panels have become more diverse, organic pigments are often used as color materials for pixels from the perspective of reliability such as heat resistance and light resistance.

[0005] Conventionally, red pigment dispersions for color filters using CI Pigment Red 242, CI Pigment Red 254, or CI Pigment Red 177 as organic pigments have been used (for example, Patent Document 1).

[0006] However, when CI Pigment Red 254 is used as an organic pigment, sublimates may be produced, causing a decrease in brightness and contrast. When CI Pigment Red 242 or CI Pigment Red 177 is used, pigment derivatives are required to disperse these organic pigments, resulting in insufficient brightness.

[0007] In recent years, brominated diketopyrrolopyrrole pigments have attracted attention as organic pigments for color filters (for example, Patent Documents 2 to 4).

[0008] However, even brominated diketopyrrolopyrrole pigments have sublimates that are currently problematic. Furthermore, demands for contrast and brightness have been increasing in recent years, leaving room for further improvement.

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-162722

[0012] Patent Document 2: Japanese Patent Application Laid-Open No. 2011-523433

[0013] Patent Document 3: Japanese Patent Application Laid-Open No. 2012-155232

[0014] Patent Document 4: Japanese Patent Application Laid-Open No. 2018-158962 Summary of the Invention

[0015] Problems to be solved by the present invention

[0016] In view of the above problems, an object of the present invention is to provide a method for producing a red coloring composition for color filters, which can suppress sublimation products caused by organic pigments and obtain a color filter excellent in contrast and brightness.

[0017] Solutions for solving problems

[0018] In light of these challenges, the present inventors have conducted intensive research and have discovered that a method for producing a red coloring composition for color filters that addresses all of the aforementioned issues can be used to obtain a red coloring composition for color filters, thereby completing the present invention. The method comprises a step of salt milling a diketopyrrolopyrrole pigment, a resin having a maleimide skeleton and a sulfonic acid group, and a sulfonate of the diketopyrrolopyrrole compound to obtain a micronized pigment; and a step of grinding a mixture containing the micronized pigment and a sulfonate of a compound having an azo group and a naphthol skeleton.

[0019] Specifically, the method for producing a red coloring composition for a color filter of the present invention comprises: a micronizing step of subjecting a diketopyrrolopyrrole pigment, a resin, and a sulfonate of a diketopyrrolopyrrole compound to a salt milling treatment to obtain a micronized pigment; and a grinding step of subjecting a mixture containing the micronized pigment and a sulfonate of a compound having an azo group and a naphthol skeleton to a grinding treatment step; the resin having a maleimide skeleton and a sulfonic acid group.

[0020] In the method for producing a red coloring composition for color filters of the present invention, it is preferred that the diketopyrrolopyrrole pigment have a bromine group.

[0021] It is preferred that the resin has repeating units based on phenylmaleimide.

[0022] The resin preferably has a sulfonic acid value of 0.1 to 20 mgKOH / g.

[0023] The present invention also relates to a red coloring composition for color filters obtained by the method for producing the above-mentioned red coloring composition for color filters.

[0024] The present invention also relates to a red colored resist composition for color filters obtained from the above-mentioned red colored composition for color filters.

[0025] Furthermore, the present invention relates to a color filter formed from the red colored resist composition for color filters.

[0026] In addition, the present invention also relates to a display device comprising the color filter.

[0027] Hereinafter, the method for producing the red coloring composition for color filters, the red coloring composition for color filters, the red coloring resist composition for color filters, the color filter, and the display device of the present invention will be described in detail.

[0028] <Method for producing a red coloring composition for color filters>

[0029] The method for producing a red coloring composition for color filters of the present invention comprises a micronizing step of subjecting a diketopyrrolopyrrole pigment, a resin, and a sulfonate of a diketopyrrolopyrrole compound to a salt milling treatment to obtain a micronized pigment, and an ink grinding step of subjecting a mixture containing the micronized pigment and a sulfonate of a compound having an azo group and a naphthol skeleton to ink grinding; the resin having a maleimide skeleton and a sulfonic acid group.

[0030] [Micro-particle formation process]

[0031] The micronization step is a step of subjecting the diketopyrrolopyrrole pigment, a resin, and a sulfonate of the diketopyrrolopyrrole compound to a salt milling treatment to obtain the micronized pigment.

[0032] First, the diketopyrrolopyrrole pigment, resin, and sulfonated product of the diketopyrrolopyrrole compound used in the micronization step will be described.

[0033] (Diketopyrrolopyrrole pigments)

[0034] Examples of the diketopyrrolopyrrole pigment include compounds represented by the following general formula (1).

[0035] [Chemical Formula 1]

[0036]

[0037] In the above general formula (1), X represents a hydrogen atom, a chlorine atom or a bromine atom, and A and B each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, an alkyl group having 1 to 12 carbon atoms, a phenyl group optionally having a substituent, -CF3, -OR 1 、-SR 2 、-N(R 3)R 4 、-COOR 5 , -CONH2, -CONHR 6 、-CON(R 7 )R 8 、-SO2NH2、-SO2NHR 9 , or -SO2N(R 10 )R 11 , and R 1 ~R 11 Each independently represents an alkyl group having 1 to 12 carbon atoms, a phenyl group which may have a substituent, or an aralkyl group which may have a substituent.

[0038] Examples of commercially available products of the diketopyrrolopyrrole pigments include CI Pigment Red 254, 255, 264, 272, and 291, and CI Pigment Orange 71, 73, and 81.

[0039] From the viewpoint of appropriately improving contrast and brightness and appropriately suppressing sublimation products, the diketopyrrolopyrrole pigment preferably has a bromine group.

[0040] Examples of the diketopyrrolopyrrole pigment having a bromine group include compounds represented by the following chemical formula, and CI Pigment Red 291 is a commercially available product thereof.

[0041] [Chemical Formula 2]

[0042]

[0043] The content of the diketopyrrolopyrrole pigment is preferably 5 to 20% by mass, more preferably 7 to 16% by mass, based on the total mass of the red coloring composition for color filters.

[0044] By containing the diketopyrrolopyrrole pigment in the above range, the contrast and brightness of a color filter obtained using the red coloring composition for color filters can be appropriately improved.

[0045] When the diketopyrrolopyrrole pigment is contained within the above-mentioned range, other red pigments may be used in combination.

[0046] Examples of the other red pigments include CI Pigment Red 177 and 242.

[0047] The content of the other red pigment is, for example, 1 to 50% by mass based on the content of the diketopyrrolopyrrole pigment.

[0048] From the viewpoint of suppressing sublimation products caused by the organic pigment and suitably improving the contrast and brightness of a color filter obtained using the red coloring composition for color filters, it is preferred that the above-mentioned other red pigments are not contained.

[0049] (resin)

[0050] The above resin has a maleimide skeleton and a sulfonic acid group.

[0051] The above resin can be obtained, for example, by copolymerizing a vinyl monomer, a monomer having a maleimide skeleton, and a monomer having a sulfonic acid group.

[0052] Examples of the vinyl monomer include (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, benzyl (meth)acrylate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl valerate, styrene, chloroprene, vinyl chloride, vinylidene chloride, acrylonitrile, 1-butene, butadiene, methacrylonitrile, vinyltoluene, ethyl vinyl ether, perfluorohexylethyl-thio-carbonyl-aminoethyl-methacrylate, isobornyl methacrylate, trifluoroethyl methacrylate, hexafluoroisopropyl methacrylate, hexafluorobutyl methacrylate, and silicone-containing vinyl monomers.

[0053] Among them, preferred are (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and benzyl (meth)acrylate. From the viewpoint of affinity with the medium used in the micronization step and the ink grinding step, and various physical properties of the resulting resin, more preferred are (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, and benzyl (meth)acrylate.

[0054] The above vinyl monomers may be used alone or in combination of two or more.

[0055] In addition, in this specification, (meth)acrylic acid means acrylic acid and methacrylic acid.

[0056] Examples of the monomer having a maleimide skeleton include N-cyclohexylmaleimide, N-phenylmaleimide, N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, N-tert-butylmaleimide, N-dodecylmaleimide, N-benzylmaleimide, and N-naphthylmaleimide.

[0057] Among them, N-phenylmaleimide is preferred from the viewpoint of appropriately suppressing sublimation products from organic pigments.

[0058] The monomers having a maleimide skeleton may be used alone or in combination of two or more.

[0059] Examples of the monomer having a sulfonic acid group include (meth)acrylamide alkylsulfonic acid, vinylsulfonic acid, (meth)acrylamide t-butylsulfonic acid, and styrenesulfonic acid.

[0060] Among these, from the viewpoint of appropriately suppressing sublimates caused by the organic pigment and appropriately improving the contrast of a color filter obtained using the red coloring composition for color filters, acrylamide-t-butylsulfonic acid is preferred.

[0061] The monomers having a sulfonic acid group may be used alone or in combination of two or more.

[0062] The mass ratios of the vinyl monomer, the monomer having a maleimide skeleton, and the monomer having a sulfonic acid group when copolymerizing the vinyl monomer are as follows.

[0063] The vinyl monomer is preferably contained in an amount of 40 to 80% by mass, more preferably 50 to 70% by mass, based on the total content (mass) of the monomers.

[0064] The content of the monomer having a maleimide skeleton is preferably 10 to 50% by mass, more preferably 20 to 40% by mass, based on the total content of the monomers.

[0065] The content of the monomer having a sulfonic acid group is preferably 1 to 10% by mass, more preferably 2.5 to 5% by mass, based on the total content of the monomers.

[0066] By copolymerizing the vinyl monomer, the monomer having a maleimide skeleton, and the monomer having a sulfonic acid group within the above range, sublimation products caused by the organic pigment can be appropriately suppressed, and the contrast of a color filter obtained using the red coloring composition for color filters can be appropriately improved.

[0067] The method for copolymerizing the vinyl monomer, the monomer having a maleimide skeleton, and the monomer having a sulfonic acid group is not particularly limited, and a known copolymerization method can be employed.

[0068] It is preferred that the resin have repeating units based on phenylmaleimide.

[0069] The resin having a repeating unit based on phenylmaleimide can appropriately suppress sublimation products caused by the organic pigment.

[0070] By including N-phenylmaleimide as the monomer having a maleimide skeleton, a resin having repeating units based on phenylmaleimide can be obtained.

[0071] The sulfonic acid value of the resin is preferably 0.1 to 20 mgKOH / g.

[0072] When the sulfonic acid value of the resin is within the above range, sublimation products from the organic pigment can be appropriately suppressed, and the contrast of a color filter obtained using the red coloring composition for color filters can be appropriately improved.

[0073] The sulfonic acid value of the resin is more preferably 6 to 18 mgKOH / g, and even more preferably 8 to 14 mgKOH / g.

[0074] The sulfonic acid value of the resin can be appropriately adjusted by adjusting the mass ratio of the monomer having a sulfonic acid group when copolymerizing the vinyl monomer, the monomer having a maleimide skeleton, and the monomer having a sulfonic acid group to be within the above range.

[0075] The sulfonic acid value is a theoretical value calculated using the amount of potassium hydroxide required to neutralize the sulfonic acid contained in 1 g of the resin as milligrams.

[0076] The weight average molecular weight of the resin is preferably 1,000 to 10,000, more preferably 2,000 to 5,000, and even more preferably 2,500 to 4,000, from the viewpoint of the productivity of the resin itself and the affinity with the medium used in the micronization step.

[0077] Furthermore, as the weight-average molecular weight, the resin was dissolved to prepare a 0.02 mass% solution, which was then passed through a filter (manufactured by GL Sciences Inc., GL Chromatodisk, water system 25A, pore size 0.2 μm). The solution was then measured under the following conditions using an alliance (manufactured by Nihon Waters K.K.) equipped with a size exclusion and refractive index detector.

[0078] Column: pLgel mixed D (manufactured by Agilent Technologies) × 2 connected in series

[0079] Detector: alliance (manufactured by Japan WATERS Co., Ltd.)

[0080] Eluent: THF

[0081] Flow rate: 1.0 mL / min

[0082] Injection volume: 100 μL

[0083] The content of the resin is preferably 0.1 to 5% by mass, more preferably 0.5 to 3% by mass, based on the total mass of the red coloring composition for color filter.

[0084] (Sulfonated diketopyrrolopyrrole compound)

[0085] In the above-mentioned micronization step, a sulfonated product of a diketopyrrolopyrrole compound is used.

[0086] By using the sulfonated product of the diketopyrrolopyrrole compound, the contrast and brightness of a color filter obtained using the red coloring composition for color filters can be appropriately improved.

[0087] Examples of the sulfonated products of the diketopyrrolopyrrole compounds include sulfonated products of CI Pigment Red 254, 255, 264, 272, and 291, and CI Pigment Orange 71 and 73.

[0088] Among these, a sulfonated product of CI Pigment Orange 71 is preferred from the viewpoint of being able to further appropriately improve the contrast and brightness of a color filter obtained using the red coloring composition for color filters.

[0089] The method for sulfonating the diketopyrrolopyrrole compound is not particularly limited, and a known method can be used.

[0090] As content of the sulfonated product of the diketopyrrolopyrrole compound, it is preferable that it is 0.1-5 mass %, and it is more preferable that it is 0.5-3 mass % based on the total mass of the red coloring composition for color filters.

[0091] By containing the sulfonated product of the diketopyrrolopyrrole compound within the above range, both the contrast and the brightness of the color filter obtained using the red coloring composition for color filters can be further appropriately improved.

[0092] (Salt grinding treatment)

[0093] As the salt milling treatment, for example, the following method can be used.

[0094] Salt milling is performed by adding an inorganic salt and an organic solvent to the diketopyrrolopyrrole pigment, the resin, and the sulfonated product of the diketopyrrolopyrrole compound, and then kneading the mixture while heating.

[0095] The kneaded product is then poured into warm water and stirred while heating to form a slurry. It is then filtered and washed repeatedly to remove inorganic salts and organic solvents, and then dried.

[0096] As the inorganic salt, a water-soluble inorganic salt is preferably used, and for example, sodium chloride, potassium chloride, sodium sulfate, etc. are preferably used.

[0097] As the inorganic salt, it is more preferable to use an inorganic salt having a primary particle size of 0.5 to 50 μm.

[0098] The amount of the inorganic salt used is preferably 3 to 20 parts by mass, more preferably 5 to 15 parts by mass, relative to 1 part by mass of the diketopyrrolopyrrole pigment.

[0099] As the organic solvent used in the salt milling treatment, it is preferable to use an organic solvent capable of suppressing the crystal growth of the organic pigment.

[0100] As such organic solvents, for example, diethylene glycol, glycerol, 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, etc. can be used.

[0101] Examples of the kneading machine used in the salt milling treatment include a kneader, a two-roll mill, a three-roll mill, and a planetary mixer.

[0102] The temperature during kneading in the salt milling treatment is preferably 30 to 150° C. The kneading time is preferably 2 to 20 hours.

[0103] The cleaning after the above-mentioned salt milling process can adopt any one of water washing and hot water washing.In addition, also acid, alkali or solvent can be used.

[0104] The above-mentioned cleaning can be repeated within the range of 1 to 5 times.

[0105] When a water-soluble inorganic salt and a water-soluble organic solvent are used as the inorganic salt and the organic solvent, the water-soluble inorganic salt and the water-soluble organic solvent can be easily removed by the washing.

[0106] The drying can be performed by heating the dryer to 80 to 120° C. using a heat source, for example, and a batch or continuous drying method can be used. Examples of the dryer include a box dryer, a belt dryer, and a spray dryer.

[0107] [Ink grinding process]

[0108] The ink grinding step is a step of subjecting a mixture containing the microparticle pigment and a sulfonated product of a compound having an azo group and a naphthol skeleton to an ink grinding step.

[0109] (Sulfonated compound having an azo group and a naphthol skeleton)

[0110] In the above-mentioned ink grinding process, a sulfonated product of a compound having an azo group and a naphthol skeleton is used.

[0111] By containing the compound having an azo group and a naphthol skeleton, the brightness of the color filter obtained using the red coloring composition for color filters can be appropriately improved. In addition, the dispersibility of the diketopyrrolopyrrole pigment can be improved, and the contrast of the color filter obtained using the red coloring composition for color filters can be improved.

[0112] Examples of the compound having an azo group and a naphthol skeleton include CI Pigment Red 2, 112, and 188, and CI Pigment Brown 25.

[0113] By sulfonating the compound having an azo group and a naphthol skeleton, a sulfonated product of the compound having an azo group and a naphthol skeleton can be obtained.

[0114] The sulfonation method is not particularly limited, and a known method can be used.

[0115] Among them, from the viewpoint of being able to further appropriately improve the brightness of the color filter obtained using the red coloring composition for color filters, a sulfonate of CI Pigment Red 188 is preferred, and from the viewpoint of appropriately improving the dispersion stability of the organic pigment and improving the contrast of the color filter obtained using the red coloring composition for color filters, a sulfonate of CI Pigment Red 2 is preferred.

[0116] The content of the sulfonated product of the compound having an azo group and a naphthol skeleton is preferably 0.1 to 5% by mass, more preferably 0.5 to 3% by mass, based on the total mass of the red coloring composition for color filter.

[0117] The mixture preferably contains a pigment dispersant, an alkali-soluble resin, and an organic solvent.

[0118] (Pigment Dispersant)

[0119] Examples of the pigment dispersant include: graft polymers having an amide backbone in the main chain and a macromonomer consisting of a methacrylate ester as a side chain, as described in Japanese Unexamined Patent Application Publication No. 3-277673, Japanese Unexamined Patent Application Publication No. 10-339949, and Japanese Translation of National ... No.75, 90, 95, etc., manufactured by Kyoei Oil and Fat Chemical Industry Co., Ltd.); cationic surfactants (W001, etc., manufactured by Yusho Co., Ltd.); nonionic surfactants such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol distearate, and sorbitan fatty acid esters; anionic surfactants (W004, W005, W017, etc., manufactured by Yusho Co., Ltd. as other commercially available products, Solsperse (ソルスパース) 3000, 5000, 9000, 12000, 13240, 13940, 17000, 20000, 24000, 26000, 28000, etc. (Zeneca (ゼネカ) Co., Ltd. manufactured) various Solsperse dispersants, Ajisper (アジスパー) PB-821, PB-822 (Japan Ajinomoto Co., Ltd. (Ajinomoto Fine-Techno Co., Inc.), IONET S-20 (manufactured by Sanyo Chemical Co., Ltd.), Disperbyk-160, 161, 162, 163, 164, 182, 184, BYK-LPN23590, BYK-LPN6919, BYK-LPN21116, BYK-LPN21234 (manufactured by BYK Chemicals), EFKA-46, 47, 48, etc. (manufactured by EFKA Chemicals BV).

[0120] Among them, from the viewpoint of micro-stabilization, a graft polymer having an amide backbone in the main chain and a macromonomer composed of methacrylate in the side chain is preferred. Specifically, a graft polymer containing vinyl pyrrolidone in the main chain and a macromonomer composed of methyl methacrylate in the side chain is preferred.

[0121] The above-mentioned pigment dispersants may be used alone or in combination of two or more.

[0122] As content of the said pigment dispersant, 1-10 mass % is preferable based on the total mass of the red coloring composition for color filters, and 2-8 mass % is more preferable.

[0123] (Alkali-soluble resin)

[0124] The alkali-soluble resin is not particularly limited as long as it is soluble in an alkaline developer used in a development step during the production of a color filter.

[0125] Among them, the alkali-soluble resin is preferably an alkali-soluble resin having a carboxyl group, and particularly preferably a copolymer of an ethylenically unsaturated monomer having one or more carboxyl groups and another copolymerizable ethylenically unsaturated monomer.

[0126] In addition, as long as the alkali-soluble resin is soluble in an alkaline developer, the copolymer of the vinyl monomer, the monomer having a maleimide skeleton, and the monomer having a sulfonic acid group may be used.

[0127] Specific examples of the copolymers of the ethylenically unsaturated monomers having one or more carboxyl groups and other copolymerizable ethylenically unsaturated monomers include copolymers of carboxyl-containing ethylenically unsaturated monomers such as acrylic acid and methacrylic acid with at least one ethylenically unsaturated monomer selected from the group consisting of styrene, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, allyl acrylate, allyl methacrylate, benzyl acrylate, benzyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, glycerol monoacrylate, glycerol methacrylate, N-phenylmaleimide, polystyrene macromonomers, and polymethyl methacrylate macromonomers, which are copolymerizable with the carboxyl-containing ethylenically unsaturated monomers.

[0128] The acid value of the copolymer is preferably 50 to 300 mgKOH / g. In this case, when the acid value is less than 50 mgKOH / g, the solubility in alkaline developer tends to decrease when the coloring composition of the present invention is used as a resist composition. On the other hand, when the acid value exceeds 300 mgKOH / g, the solubility in alkaline developer becomes excessively high, and during development with an alkaline developer, the colored layer tends to fall off the substrate and crack the surface of the colored layer.

[0129] The acid value of the copolymer can be measured by potentiometric titration (JIS K 0070: 1992).

[0130] The weight-average molecular weight of the alkali-soluble resin is generally preferably 1,000 to 100,000. When the weight-average molecular weight of the alkali-soluble resin is less than 1,000, solubility in alkaline developer solutions may increase, resulting in decreased developing properties. On the other hand, when the weight-average molecular weight exceeds 100,000, solubility in organic solvents may decrease, and when the coloring composition of the present invention is used as a resist composition, the viscosity may increase.

[0131] The weight average molecular weight of the alkali-soluble resin can be measured by the same method as that for the weight average molecular weight of the resin.

[0132] The content of the alkali-soluble resin is preferably 5 to 50% by mass based on the total mass of the red coloring composition for color filter.

[0133] (Organic solvent)

[0134] As the organic solvent, it is preferably at normal pressure (1.013×10 2 kPa) with a boiling point of 100 to 220°C, such as ester organic solvents, ether organic solvents, ether ester organic solvents, ketone organic solvents, aromatic hydrocarbon solvents and nitrogen-containing organic solvents.

[0135] Among the above-mentioned organic solvents, from the viewpoint of improving solubility, pigment dispersibility, coating properties, etc., more preferred are diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, cyclohexanone, 2-heptanone, ethyl 2-hydroxypropionate, 3-methyl-3-methoxybutyl propionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, n-pentyl formate, and the like. Propylene glycol monomethyl ether acetate is even more preferred.

[0136] The above-mentioned organic solvents may be used alone or in combination of two or more.

[0137] From the viewpoint of improving the solubility of the alkali-soluble resin, pigment dispersibility, coating properties, etc., the content of the organic solvent is preferably 30 to 80% by mass, more preferably 35 to 75% by mass, based on the total mass of the red coloring composition for color filter.

[0138] (Ink grinding process)

[0139] In the ink grinding step, the mixture containing the various components is ground into ink.

[0140] There are no particular limitations on the method for the above-mentioned ink grinding treatment. For example, a bead mill, a ready mill, an ultrasonic homogenizer, a high-pressure homogenizer, a paint shaker, a ball mill, a roller mill, a sand mill, a sand grinder, a Dyno-Mill, a high-speed disperser (DISPERMAT), an SC mill, a high-pressure homogenizer (Nanomizer), etc. can be used to perform the ink grinding treatment by a known method.

[0141] <Red coloring composition for color filter>

[0142] The present invention also relates to a red coloring composition for color filters obtained by the method for producing the above-mentioned red coloring composition for color filters.

[0143] The red coloring composition for color filter of the present invention is obtained by the method for producing a red coloring composition for color filter of the present invention. Therefore, sublimation of organic pigments can be suppressed, and a color filter excellent in contrast and brightness can be obtained.

[0144] <Red coloring resist composition for color filter>

[0145] The present invention also relates to a red colored resist composition for color filters obtained from the above-mentioned red colored composition for color filters.

[0146] The red colored resist composition for color filter of the present invention can be obtained by adding an alkali-soluble resin, a photopolymerizable compound, a photopolymerization initiator, an organic solvent, and additives as needed in addition to the above-mentioned red colored resist composition for color filter.

[0147] (Red coloring composition for color filter)

[0148] The red coloring resist composition for color filters of the present invention contains the red coloring composition for color filters of the present invention.

[0149] As content of the said red coloring composition for color filters, it is preferable that it is 30-80 mass % based on the total mass of the red coloring resist composition for color filters of this invention, and it is more preferable that it is 40-75 mass %.

[0150] (Alkali-soluble resin)

[0151] As the alkali-soluble resin, the alkali-soluble resins described in the method for producing the red coloring composition for color filter can be appropriately selected and used.

[0152] The content of the alkali-soluble resin is preferably 1 to 35% by mass, more preferably 3 to 30% by mass, based on the total mass of the red colored resist composition for color filter of the present invention.

[0153] (Photopolymerizable compound)

[0154] Examples of the photopolymerizable compound include monomers and oligomers having one or more photopolymerizable unsaturated bonds in the molecule. The photopolymerizable unsaturated bond is an unsaturated bond that can be polymerized by the action of free radicals or cations generated when the photopolymerization initiator described below is decomposed by active energy rays such as ultraviolet rays and electron beams.

[0155] Examples of the monomer having one photopolymerizable unsaturated bond in the molecule include: alkyl methacrylates or alkyl acrylates such as methyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl methacrylate, methyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; aryl methacrylates or aryl acrylates such as benzyl methacrylate and benzyl acrylate; alkoxyalkyl methacrylates or alkoxyalkyl acrylates such as butoxyethyl methacrylate and butoxyethyl acrylate; aminoalkyl methacrylates or aminoalkyl acrylates such as N,N-dimethylaminoethyl methacrylate and N,N-dimethylaminoethyl acrylate; methacrylates or acrylates of polyalkylene glycol alkyl ethers such as diethylene glycol ethyl ether, triethylene glycol butyl ether, and dipropylene glycol methyl ether; methacrylates or acrylates of polyalkylene glycol aryl ethers such as hexaethylene glycol phenyl ether; isobornyl methacrylate or isobornyl acrylate; glyceryl methacrylate or glyceryl acrylate; 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate, and the like.

[0156] In this specification, (meth)acrylate means acrylate and methacrylate.

[0157] Examples of the monomer having two or more photopolymerizable unsaturated bonds in the molecule include bisphenol A dimethacrylate, 1,4-butylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, diethylene glycol dimethacrylate, glycerol dimethacrylate, neopentyl glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol tetramethacrylate, and the like. Acrylates, dipentaerythritol hexamethacrylate, dipentaerythritol pentamethacrylate, bisphenol A diacrylate, 1,4-butanediol diacrylate, 1,3-butanediol diacrylate, diethylene glycol diacrylate, glycerol diacrylate, neopentyl glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, tetraethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, etc.

[0158] The above-mentioned photopolymerizable compounds can be used alone or in combination of two or more.

[0159] The content of the photopolymerizable compound is preferably 0.5 to 20% by mass, more preferably 1 to 10% by mass, based on the total mass of the red colored resist composition for color filter of the present invention.

[0160] (Photopolymerization initiator)

[0161] The photopolymerization initiator is not particularly limited as long as it is a polymerization initiator that can generate free radicals or cations by irradiation with active energy rays such as ultraviolet rays and electron beams, and examples thereof include benzophenone, N,N'-tetraethyl-4,4'-diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, benzyl, 2,2-diethoxyacetophenone, benzoin, benzoin methyl ether, benzoin isobutyl ether, and benzyl. 1-Hydroxy-2-methyl-1-[4-(methylthio)phenyl]-2-morpholine-1-propanone, triazine-based photopolymerization initiators, etc.

[0162] The above-mentioned photopolymerization initiators can be used alone or in combination of two or more.

[0163] The content of the photopolymerization initiator is preferably 0.1 to 5% by mass, more preferably 0.5 to 3% by mass, based on the total mass of the red colored resist composition for color filter of the present invention.

[0164] (Organic solvent)

[0165] As the organic solvent, the organic solvents described in the method for producing the red coloring composition for color filter can be appropriately selected and used.

[0166] The content of the organic solvent is preferably 1 to 40% by mass, more preferably 5 to 35% by mass, based on the total mass of the red colored resist composition for color filter of the present invention.

[0167] (Other additives)

[0168] The red colored resist composition for color filter of the present invention may further contain additives within a range not impairing the effects of the present invention.

[0169] Examples of the additives include various additives such as thermal polymerization inhibitors, silane coupling agents, titanate coupling agents, ultraviolet absorbers, and antioxidants.

[0170] (Method for producing a red colored resist composition for color filters)

[0171] The method for producing the red colored resist composition for color filter of the present invention is not particularly limited, and the composition can be obtained by mixing the above-mentioned materials and performing a grinding process by a known method.

[0172] (Red coloring resist composition for color filter)

[0173] The red coloring resist composition for the color filter of the present invention is applied to a glass substrate using a spin coater, pre-baked at 100°C for 3 minutes, exposed to a high-pressure mercury lamp, and post-baked at 230°C for 30 minutes to obtain a coating film, which is measured using a spectrophotometer (manufactured by Shimadzu Corporation, UV-2500PC, C light source 2° field of view). The measured chromaticity (chromaticity) at x=0.6400 and y=0.3290 shows a contrast ratio of preferably 6200 or more, more preferably 6500 or more, further preferably 6800 or more, particularly preferably 7000 or more, and most preferably 7100 or more.

[0174] The above contrast ratios are values when a blank is set to 10,000.

[0175] The red coloring resist composition for the color filter of the present invention is applied to a glass substrate using a spin coater, pre-baked at 100°C for 3 minutes, exposed to a high-pressure mercury lamp, and post-baked at 230°C for 30 minutes to obtain a coating film. The coating film is measured using a spectrophotometer (manufactured by Shimadzu Corporation, UV-2500PC, C light source 2° field of view). The measured chromaticity x = 0.6400, y = 0.3290 is preferably 22.5 or more, more preferably 22.7, and even more preferably 22.8 or more.

[0176] Color Filters

[0177] The present invention also relates to a color filter formed using the above-mentioned red coloring resist composition for color filter.

[0178] The color filter of the present invention includes a red filter portion, a green filter portion, and a blue filter portion, wherein the red filter portion is formed from the red colored resist composition for color filter of the present invention.

[0179] The green filter portion and the blue filter portion can be formed using known materials and methods.

[0180] The color filter of the present invention can be produced by appropriately selecting and using a known method such as a printing method or a photolithography method.

[0181] <Display device>

[0182] The present invention is also a display device including the above-mentioned color filter.

[0183] The display device of the present invention is not particularly limited as long as it includes the color filter of the present invention described above, and examples thereof include known liquid crystal display devices and touch panels.

[0184] Effects of the Invention

[0185] The present invention can provide a method for producing a red coloring composition for color filters, which can suppress sublimation products caused by organic pigments and can provide a color filter having excellent contrast and brightness. DETAILED DESCRIPTION

[0186] The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples. In addition, unless otherwise specified, "%" means "mass %" and "parts" means "mass parts".

[0187] The materials used in Examples and Comparative Examples are as follows.

[0188] Organic pigments

[0189] (PR291)

[0190] CI Pigment Red 291

[0191] (PR254)

[0192] CI Pigment Red 254

[0193] (PR177)

[0194] CI Pigment Red 177

[0195] (PR242)

[0196] CI Pigment Red 242

[0197] <Sulfonated products>

[0198] (PR188S)

[0199] 30 mL of concentrated sulfuric acid was placed in a 100 mL Erlenmeyer flask. 10 g of CI Pigment Red 188 was added while stirring with a magnetic stirrer. The mixture was stirred at room temperature for 30 minutes. A mixture of 50 g of water and 50 g of ice was placed in a 1 L beaker. The reaction mixture was poured into the ice water and stirred with a magnetic stirrer for 30 minutes. The product was filtered under reduced pressure, washed with water, and the resulting solid was dried to obtain PR188S.

[0200] (PO71S)

[0201] PO71S was obtained in the same manner as in the above-mentioned method for producing PR188S, except that CI Pigment Red 188 was changed to CI Pigment Orange 71.

[0202] <Resin>

[0203] (Resin 1)

[0204] Butyl methacrylate (50 parts by mass), methacrylic acid (5 parts by mass), N-phenylmaleimide (40 parts by mass), and acrylamido-tert-butylsulfonic acid (5 parts by mass) were randomly copolymerized by a known method to obtain resin 1.

[0205] The sulfonic acid value of resin 1 was 14 mgKOH / g, and the weight average molecular weight was 3,000.

[0206] (Resin 2)

[0207] Butyl methacrylate (90 parts by mass), methacrylic acid (5 parts by mass), and acrylamido-tert-butylsulfonic acid (5 parts by mass) were randomly copolymerized by a known method to obtain Resin 2.

[0208] The sulfonic acid value of resin 2 was 14 mgKOH / g, and the weight average molecular weight was 3,000.

[0209] (Resin 3)

[0210] Butyl methacrylate (55 parts by mass), methacrylic acid (5 parts by mass), and N-phenylmaleimide (40 parts by mass) were randomly copolymerized by a known method to obtain Resin 3.

[0211] Resin 3 had a sulfonic acid value of 0 mgKOH / g and a weight average molecular weight of 3,000.

[0212] The sulfonic acid values of the resins 1 to 3 are theoretical values calculated as the amount of potassium hydroxide required to neutralize the sulfonic acid contained in 1 g of the resin in milligrams.

[0213] Separately, the resin was dissolved to prepare a 0.02 mass % solution, and the solution was passed through a filter (manufactured by GL Sciences Inc., GL Chromatodisk, Water 25A, pore size 0.2 μm). The weight average molecular weight was then measured under the following conditions using an alliance (manufactured by Nippon Waters Co., Ltd.) equipped with a size exclusion chromatograph and a refractive index detector.

[0214] Column: pLgel mixed D (manufactured by Agilent) × 2 connected in series

[0215] Detector: alliance (manufactured by Japan WATERS Co., Ltd.)

[0216] Eluent: THF

[0217] Flow rate: 1.0 mL / min

[0218] Injection volume: 100 μL

[0219] Pigment dispersants

[0220] (BYK-LPN23590)

[0221] BYK-LPN23590 (manufactured by BYK Chemie, solid content 50%, AB block structure, acrylic acid)

[0222] <Alkali-soluble resin>

[0223] (ZAH110)

[0224] PHORET ZAH110 (manufactured by Soken Chemical Co., Ltd., solid content 35%)

[0225] Organic solvents

[0226] (PGMEA)

[0227] Propylene glycol monomethyl ether acetate

[0228] (PGME)

[0229] Propylene glycol monomethyl ether

[0230] <Photopolymerizable compounds>

[0231] (DPEHA)

[0232] Dipentaerythritol hexaacrylate

[0233] <Photopolymerization initiator>

[0234] (Or907)

[0235] 2-Benzyl-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone (trade name: Omnirad 907, manufactured by IGM Resins BV)

[0236] <Microparticle organic pigment>

[0237] (Microparticle PR291-1)

[0238] Into the tank of a kneader (trade name KHD-2, manufactured by Inoue Seisakusho Co., Ltd.), 10 parts by mass of PR291, 1 part by mass of PO71S, 1 part by mass of Resin 1, 200 parts by mass of sodium chloride having a particle size of 20 μm, and 240 parts by mass of diethylene glycol were placed, and kneaded at 50° C. for 12 hours, followed by salt milling to obtain a kneaded product.

[0239] Next, 200 parts by mass of the obtained kneaded product was added to 2 liters of warm water, and stirred for 1 hour while heating to 40° C. to form a slurry.

[0240] Then, filtration and water washing were repeated to remove sodium chloride and diethylene glycol, and then the mixture was dried at 40° C. to obtain micronized PR291-1.

[0241] (Microparticle PR291-2)

[0242] Microparticulated PR291-2 was obtained in the same manner as in the production of the microparticulated PR291-1, except that PO71S was not used.

[0243] (Microparticle PR254-1)

[0244] Into the tank of a kneader (trade name KHD-2, manufactured by Inoue Seisakusho Co., Ltd.), 10 parts by mass of PR254, 1 part by mass of PO71S, 1 part by mass of Resin 1, 200 parts by mass of sodium chloride having a particle size of 20 μm, and 240 parts by mass of diethylene glycol were placed, and kneaded at 50° C. for 12 hours, followed by salt milling to obtain a kneaded product.

[0245] Next, 200 parts by mass of the obtained kneaded product was added to 2 liters of warm water, and stirred for 1 hour while heating to 40° C. to form a slurry.

[0246] Then, filtration and water washing were repeated to remove sodium chloride and diethylene glycol, and then the mixture was dried at 40° C. to obtain micronized PR254-1.

[0247] (Microparticle PR254-2)

[0248] In the production of the above-mentioned micronized PR254-1, micronized PR254-2 was obtained in the same manner except that resin 2 was used instead of resin 1.

[0249] (Microparticle PR254-3)

[0250] In the production of the above-mentioned micronized PR254-1, micronized PR254-3 was obtained in the same manner except that resin 3 was used instead of resin 1.

[0251] (Microparticle PR254-4)

[0252] Microparticulated PR254-4 was obtained in the same manner as in the production of the microparticulated PR254-1, except that the resin 1 was not used.

[0253] (Microparticle PR242)

[0254] Into the tank of a kneader (trade name KHD-2, manufactured by Inoue Seisakusho Co., Ltd.), 10 parts by mass of PR242, 1 part by mass of PO71S, 1 part by mass of Resin 1, 200 parts by mass of sodium chloride having a particle size of 20 μm, and 240 parts by mass of diethylene glycol were placed, and kneaded at 50° C. for 12 hours, followed by salt milling to obtain a kneaded product.

[0255] Next, 200 parts by mass of the obtained kneaded product was added to 2 liters of warm water, and stirred for 1 hour while heating to 40° C. to form a slurry.

[0256] Then, filtration and water washing were repeated to remove sodium chloride and diethylene glycol, and then the mixture was dried at 40° C. to obtain micronized PR242.

[0257] (Microparticle PR177)

[0258] Into the tank of a kneader (trade name KHD-2, manufactured by Inoue Seisakusho Co., Ltd.), 10 parts by mass of PR177, 1 part by mass of PO71S, 1 part by mass of Resin 1, 200 parts by mass of sodium chloride having a particle size of 20 μm, and 240 parts by mass of diethylene glycol were placed, and kneaded at 50° C. for 12 hours, followed by salt milling to obtain a kneaded product.

[0259] Next, 200 parts by mass of the obtained kneaded product was added to 2 liters of warm water, and stirred for 1 hour while heating to 40° C. to form a slurry.

[0260] Then, filtration and water washing were repeated to remove sodium chloride and diethylene glycol, and then the mixture was dried at 40° C. to obtain micronized PR177.

[0261] <Production of Red Coloring Composition for Color Filter>

[0262] Various materials were mixed to give the compositions shown in Table 1, and milled for 60 minutes using a ready mill (bead diameter 0.2 nm, filling rate 50%) to obtain red coloring compositions for color filters of Examples and Comparative Examples.

[0263] [Table 1]

[0264]

[0265] <Production of Red Colored Resist Composition for Color Filter>

[0266] After uniformly mixing various materials using a high-speed stirrer to obtain the compositions shown in Table 2, the mixture was filtered using a membrane filter having a pore size of 3 μm to obtain red colored resist compositions for color filters according to Examples and Comparative Examples.

[0267] (Preparation of Evaluation Samples)

[0268] The red colored resist compositions for color filters of Examples and Comparative Examples were each applied on a glass substrate using a spin coater to have the same film thickness.

[0269] Next, after prebaking at 100° C. for 3 minutes, the samples were exposed to a high-pressure mercury lamp and post-baked at 230° C. for 30 minutes to obtain samples for evaluation.

[0270] (Optical properties evaluation)

[0271] The contrast and brightness Y of each evaluation sample were measured at chromaticity x=0.6400 and y=0.3290 using a spectrophotometer (manufactured by Shimadzu Corporation, UV-2500PC, light source C, 2° field of view).

[0272] In addition, in the measurement of contrast, the blank was set to 10,000.

[0273] (Sublimation Evaluation)

[0274] Each of the evaluation samples was observed with an optical microscope, and then further baked at 260° C. for 30 minutes. The samples were then observed again with an optical microscope and evaluated according to the following evaluation criteria. The results are shown in Table 2.

[0275] ○: No sublimates were observed even after baking at 260°C.

[0276] Δ: Although no sublimates were observed after baking at 230°C, some sublimates were observed after baking at 260°C.

[0277] ×: Sublimates were observed after baking at 230°C.

[0278] [Table 2]

[0279]

[0280] Regarding the red colored resist compositions for color filters of Examples 3 and 4 using the red colored compositions for color filters of Examples, it was confirmed that the contrast and brightness of the evaluation samples were excellent and sublimation of the organic pigment was suppressed.

[0281] Furthermore, from the comparison between Example 3 and Comparative Example 7, it was confirmed that the contrast can be further appropriately improved by including a sulfonated product of a diketopyrrolopyrrole compound during the salt milling treatment.

[0282] In addition, in Comparative Example 8 using CI Pigment Red 242 as the organic pigment and Comparative Example 9 using CI Pigment Red 177 as the organic pigment, the brightness was insufficient.

[0283] In addition, compared with Example 4, in Comparative Example 10 using a resin without a maleimide skeleton, Comparative Example 11 using a resin without a sulfonic acid group, and Comparative Example 12 using no resin during salt milling, sublimates were generated, and the contrast and brightness were also insufficient.

[0284] Industrial Applicability

[0285] The method for producing a red coloring composition for color filters of the present invention can provide a red coloring composition for color filters that can suppress sublimation products caused by organic pigments and can produce a color filter with excellent contrast and brightness. Therefore, it can be suitably used as a red coloring resist composition for color filters used in liquid crystal display devices, touch panels, etc.

Claims

1. A method for producing a red coloring composition for a color filter, comprising: a micronization step of subjecting the diketopyrrolopyrrole pigment, a resin, and a sulfonate of the diketopyrrolopyrrole compound to salt milling to obtain the micronized pigment; as well as In the ink grinding step, a mixture containing the microparticle pigment and a sulfonated product of a compound having an azo group and a naphthol skeleton is subjected to an ink grinding process. The resin has a maleimide skeleton and a sulfonic acid group.

2. The method for producing a red coloring composition for color filter according to claim 1, wherein The diketopyrrolopyrrole pigment has a bromine group.

3. The method for producing a red coloring composition for color filter according to claim 1 or 2, wherein The resin has repeating units based on phenylmaleimide.

4. The method for producing a red coloring composition for color filter according to claim 1 or 2, wherein The sulfonic acid value of the resin is 0.1 mgKOH / g to 20 mgKOH / g. 5 . A red coloring composition for color filter, obtained by the method for producing a red coloring composition for color filter according to claim 1 . 6 . A red colored resist composition for color filters, obtained from the red colored composition for color filters according to claim 5 . 7 . A color filter formed using the red colored resist composition for color filter according to claim 6 . A display device comprising the color filter according to claim 7 .

Images