Method for producing organic pigment composition, method for producing coating film, and method for evaluating brightness of coating film

Abstract

The present invention relates to a method for producing an organic pigment composition, a method for producing a coating film, and a method for evaluating the brightness of the coating film. Specifically, the present invention relates to a method for producing an organic pigment composition containing at least organic pigment particles, characterized in that the diffuse reflectance of the organic pigment particles is controlled to increase the brightness of a color filter. The brightness of the color filter is controlled to be high by increasing the ratio of the diffuse reflectance area of ​​the organic pigment particles in a target wavelength range relative to the total diffuse reflectance area of ​​the diffuse reflectance spectrum in the wavelength range of 380 to 780 nm. The brightness of the color filter is controlled to be high by covering at least a portion of the surface of the organic pigment particles with an amorphous oxide.

Description

[0001] This application is a divisional application of Chinese patent application No. 201780061720.0 with the same invention name. The original international application number is PCT / JP2017 / 036711, and the international application date is October 10, 2017. Technical Field

[0002] The present invention relates to a method for producing an organic pigment composition, a method for producing a coating film, a method for evaluating the brightness (luminance) of the coating film, and a method for producing a color filter. Furthermore, the present invention relates to organic pigment particles for a color filter and a color filter. Background Art

[0003] Organic pigments are generally more durable than dyes and have higher tinting power than inorganic pigments, and therefore are widely used as coloring materials. Various production methods are known.

[0004] One application of such organic pigments is color filters. Color filters are used in imaging elements used in liquid crystal displays such as liquid crystal displays and organic EL displays, as well as input devices such as digital cameras and color copiers. Color filters are manufactured by patterning various colors using methods such as photolithography using a mixture of a photosensitive resin composition and a pigment dispersion, or inkjet printing, which uses an inkjet printer to directly apply a colored ink onto a substrate without a mask.

[0005] For more vivid color reproduction, strongly require that color filter has high contrast, high brightness and transparency, particularly for the color filter using organic pigment, this tendency is stronger. Organic pigment is known to realize the raising of high contrast and transparency by its particle size miniaturization, sphericization. Therefore, for example, in patent documentation 1, put down in writing: by dissolving organic pigment in good solvents such as organic solvent, strong acid, continuously drop into poor solvent and carry out crystallization, thus obtain the particle of spherical and small organic pigment. In addition, as the organic pigment of above-mentioned microparticle, influence the height and the transparency of contrast according to the difference of dispersion state. In order to realize dispersion efficiently, need the microparticle of organic pigment to the wetting technology of dispersant and dispersion medium, by controlling its dispersion state, also can realize high contrast of color filter, transparency (for example, patent documentation 2).

[0006] However, even if high contrast and transparency can be achieved in color filters, achieving high brightness becomes a significant problem. Even if the organic pigment is sphericalized or micronized, and its dispersion in the dispersion medium is improved, this has no effect on brightness. Despite this, the only practical method for achieving high brightness in color filters is to apply a dispersion of spherical or micronized organic pigments in a solvent onto glass, bake (heat treat) the resulting film, and then measure the brightness of the film to determine the brightness.

[0007] Regarding the high brightness of color filters, there have been proposed methods of using a pigment composition that mixes pigments and dyes, and methods of increasing brightness by using a pigment composition that improves the dispersion stability of fine particles of pigments containing specific different pigment types (Patent Documents 3 and 4). However, these methods measure the brightness of color filters that have been baked and coated, and do not focus on the color characteristics of the organic pigments themselves. Since the brightness is evaluated by evaluating the modulated dispersion and the coating made using it, the influence of the characteristics of the organic pigment particles themselves on the brightness cannot be accurately evaluated based on the resin or dispersant contained in the coating, and the compatibility with other by-product compositions, and the fundamental reason for controlling the brightness of the color filter cannot be characterized. In this way, since the brightness of the organic pigment particles themselves cannot be controlled, the high brightness of the color filter cannot be fundamentally controlled. Regarding the high brightness of the color filter, it is desired to establish a control method.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: International Publication No. 2011 / 096401 Pamphlet

[0011] Patent Document 2: Japanese Patent Application Laid-Open No. 2014-126585

[0012] Patent Document 3: Japanese Patent Application Laid-Open No. 2008-268486

[0013] Patent Document 4: Japanese Patent Application Publication No. 2016-61979 Summary of the Invention

[0014] Problems to be solved by the invention

[0015] In view of this situation, the present invention aims to provide a method for producing an organic pigment composition containing at least organic pigment particles with controlled diffuse reflectance, in order to improve the brightness of a color filter. The present inventors discovered a correlation between the diffuse reflectance of the organic pigment particles and the brightness of a color filter coated with a film made using the organic pigment particle dispersion. They discovered that controlling the diffuse reflectance of the organic pigment particles can achieve higher brightness in the color filter, leading to the completion of the present invention.

[0016] In addition, in view of the above situation, the present invention aims to provide a method for producing a coating film produced using an organic pigment fine particle dispersion as an organic pigment composition, a method for evaluating the brightness of the coating film, and a method for producing a color filter including a step of forming a coating film on a substrate for a color filter.

[0017] In view of the above circumstances, an object of the present invention is to provide organic pigment particles for a color filter and a color filter including the organic pigment particles for a color filter.

[0018] Means of solving problems

[0019] Specifically, the present invention provides a method for producing an organic pigment composition containing at least organic pigment fine particles, wherein the method comprises controlling the diffuse reflectance of the organic pigment fine particles in order to improve the brightness in a color filter.

[0020] In addition, the present invention preferably controls the brightness of the color filter to be higher by controlling the ratio of the area of ​​the diffuse reflectance in the target wavelength range to the total area of ​​the diffuse reflectance in the entire measurement wavelength range in the diffuse reflectance spectrum of the organic pigment particles in the wavelength range of 380 to 780 nm to be higher. In addition, the present invention preferably controls the brightness of the color filter to be higher by covering at least a portion of the surface of the organic pigment particles with an oxide, preferably an oxide containing amorphous matter. In addition, in the present invention, the oxide is preferably silicon oxide. In addition, the present invention preferably uses a powder of the organic pigment particles to measure the diffuse reflectance spectrum.

[0021] In addition, in the present invention, when the above-mentioned organic pigment particles are red pigment particles, it is preferred that: the above-mentioned target wavelength range is 620~750nm, and the ratio of the area of ​​the diffuse reflectance in the target wavelength range to the total area of ​​the diffuse reflectance in the entire measurement wavelength region is 71% or more; when the above-mentioned organic pigment particles are blue pigment particles, it is preferred that: the above-mentioned target wavelength range is 450~495nm, and the ratio of the area of ​​the diffuse reflectance in the target wavelength range to the total area of ​​the diffuse reflectance in the entire measurement wavelength region is 30% or more; when the above-mentioned organic pigment particles are green pigment particles, it is preferred that: the above-mentioned target wavelength range is 495~570nm, and the ratio of the area of ​​the diffuse reflectance in the target wavelength range to the total area of ​​the diffuse reflectance in the entire measurement wavelength region is 51% or more.

[0022] In the present invention, the organic pigment composition is an organic pigment fine particle dispersion, and can be implemented as a method for producing an organic pigment composition comprising the following steps (I) to (III).

[0023] Step (I): a step of obtaining at least one organic pigment microparticle,

[0024] Step (II): a step of measuring the diffuse reflectance of the organic pigment particles.

[0025] Step (III): a step of dispersing the organic pigment fine particles in a solvent to obtain an organic pigment fine particle dispersion.

[0026] In addition, the present invention can be implemented as a method for producing a coating film by using an organic pigment particle dispersion obtained by the method for producing an organic pigment composition including the above-mentioned steps (I) to (III) to control the brightness of the above-mentioned coating film, and the brightness of the above-mentioned coating film is preferably controlled by controlling the diffuse reflectance of the above-mentioned organic pigment particles.

[0027] The present invention also provides a method for evaluating the brightness of a coating film produced using an organic pigment fine particle dispersion, wherein the diffuse reflectance of the organic pigment fine particle powder is measured and the brightness of the coating film is evaluated using the relationship obtained in steps (I) to (IV).

[0028] Step (I): a step of obtaining at least one organic pigment microparticle,

[0029] Step (II): a step of measuring the diffuse reflectance of the powder of the organic pigment fine particles in the wavelength range of 380 to 780 nm,

[0030] Step (III): a step of dispersing the organic pigment particles in a solvent to obtain an organic pigment particle dispersion.

[0031] Step (IV): a step of measuring the brightness of a coating film produced using the organic pigment fine particle dispersion and determining the relationship between the brightness of the coating film and the ratio of the diffuse reflectance area in the target wavelength range to the total diffuse reflectance area in the entire measurement wavelength range.

[0032] The present invention also provides an organic pigment composition containing at least organic pigment fine particles, wherein the diffuse reflectance of the organic pigment fine particles is controlled in order to control the brightness in a color filter.

[0033] The present invention also provides a method for manufacturing a color filter, wherein the method for manufacturing the coating film includes forming the coating film on a substrate for the color filter, and controlling the diffuse reflectance of the organic pigment particles to obtain a color filter with controlled brightness.

[0034] In addition, the present invention provides organic pigment particles for color filters, wherein, in the diffuse reflectance spectrum of the above-mentioned organic pigment particles in the wavelength range of 380 to 780 nm, the above-mentioned organic pigment particles are red pigment particles, the target wavelength range is 620 to 750 nm, and the ratio of the area of ​​the diffuse reflectance in the target wavelength range to the total area of ​​the diffuse reflectance in the entire measurement wavelength range is greater than 71%.

[0035] In addition, the present invention provides organic pigment particles for color filters, wherein, in the diffuse reflectance spectrum of the above-mentioned organic pigment particles in the wavelength range of 380 to 780 nm, the above-mentioned organic pigment particles are blue pigment particles, the target wavelength range is 450 to 495 nm, and the ratio of the area of ​​the diffuse reflectance in the target wavelength range to the total area of ​​the diffuse reflectance in the entire measurement wavelength range is greater than 30%.

[0036] In addition, the present invention provides organic pigment particles for color filters, wherein, in the diffuse reflectance spectrum of the above-mentioned organic pigment particles in the wavelength range of 380 to 780 nm, the above-mentioned organic pigment particles are green pigment particles, the target wavelength range is 495 to 570 nm, and the ratio of the area of ​​the diffuse reflectance in the target wavelength range to the total area of ​​the diffuse reflectance in the entire measurement wavelength range is greater than 51%.

[0037] In the present invention, it is preferred that at least a portion of the surface of the organic pigment fine particles be covered with silicon oxide, and it is preferred that the silicon oxide contain an amorphous substance.

[0038] Furthermore, the present invention provides a color filter comprising the above-mentioned organic pigment fine particles for a color filter.

[0039] The present invention also provides a color filter comprising the organic pigment particles for use in a color filter and organic pigment particles having a color different from that of the organic pigment particles. In the present invention, the organic pigment particles having a color different from that of the organic pigment particles may be organic pigment particles having a color different from that of the organic pigment particles for use in the color filter, and may be, for example, organic pigment particles having a complementary color.

[0040] The color filter exhibits both higher diffuse reflectance and higher brightness than color filters using bead milled organic pigment particles. Bead milled organic pigment particles are obtained by pulverizing the raw organic pigments in a bead mill to form microparticles when producing organic pigment particles for color filters.

[0041] Effects of the Invention

[0042] According to the present invention, an organic pigment composition capable of controlling the brightness of a color filter can be obtained, and this organic pigment composition can be used to manufacture a color filter with enhanced brightness. Since the brightness of the organic pigment particles used as color filters is evaluated, there is no need to actually coat and evaluate all the target pigment particles, as is conventionally done. This not only simplifies color filter development but also reduces time and costs by eliminating the need for coating for evaluation.

[0043] Furthermore, the present invention can provide a new method for producing a coating film using an organic pigment composition and an effective method for evaluating the brightness of the coating film.

[0044] Furthermore, the present invention can provide a method for manufacturing a color filter using new knowledge about the relationship between the diffuse reflectance of organic pigment particles and the brightness of the color filter.

[0045] Furthermore, the present invention can provide organic pigment particles for a color filter using the above-mentioned knowledge, and a color filter including the organic pigment particles for a color filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] [ Figure 1 ] are the diffuse reflectance spectrum measurement results of PR254 fine particle powder obtained in Examples 1, 2, 3 and 7 of the present invention.

[0047] [ Figure 2 ] is a graph showing the area ratio (DiR) [%] of the diffuse reflectance of the target wavelength region of the PR254 microparticle powder or the PR254 microparticle powder covered with silicon oxide obtained in Examples 1 to 10, Example F-1, and Example F-2 of the present invention relative to the brightness in the color filter characteristic evaluation.

[0048] [ Figure 3 ] are the diffuse reflectance spectrum measurement results of the copper phthalocyanine microparticle powder or the copper phthalocyanine microparticle powder covered with silicon oxide obtained in Example 11 and Example 14 of the present invention.

[0049] [ Figure 4 ] is a graph showing the area ratio (DiR) [%] of the diffuse reflectance in the target wavelength region of the copper phthalocyanine fine particle powder or the silicon oxide-covered copper phthalocyanine fine particle powder obtained in Examples 11 to 15 of the present invention relative to the brightness in the color filter characteristic evaluation.

[0050] [ Figure 5 ] are the diffuse reflectance spectrum measurement results of the PG58 microparticle powder or the PG58 microparticle powder covered with silicon oxide obtained in Examples 17 and 20 of the present invention.

[0051] [ Figure 6 ] is a graph showing the area ratio (DiR) [%] of the diffuse reflectance in the target wavelength region of the PG58 fine particle powder or the PG58 fine particle powder covered with silicon oxide obtained in Examples 16 to 20 of the present invention relative to the brightness in the color filter characteristic evaluation.

[0052] [ Figure 7 ] is the IR measurement result of PR254 particles covered with silicon oxide obtained in Example 10 of the present invention. DETAILED DESCRIPTION

[0053] Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. However, the aspects of the present invention are not limited to the embodiment described below.

[0054] (particle)

[0055] In the present invention, microparticles refer to microparticles having a primary particle size of 500 nm or less, preferably 100 nm or less, and more preferably 30 nm or less. The shape of the particles or microparticles is not particularly limited, and may be, for example, particles or aggregates thereof in the form of a substantially cylindrical, spherical, disc-shaped, triangular prism-shaped, quadrangular prism-shaped, polyhedron-shaped, or ellipsoidal sphere.

[0056] (Organic Pigments)

[0057] As the organic pigment in the present invention, there is no particular limitation. For example, all organic pigments registered in the Society of Dyers and Colorists can be cited. Among them, for example, for organic pigments constituting green, organic pigments classified in CI pigment green can be cited; for organic pigments constituting blue, organic pigments classified in CI pigment blue can be cited; for organic pigments constituting white, organic pigments classified in CI pigment white can be cited; for organic pigments constituting yellow, organic pigments classified in CI pigment yellow can be cited; for organic pigments constituting red, organic pigments classified in CI pigment red in the color index can be cited; and organic pigments classified in CI pigment violet and CI pigment orange, etc. More specifically, examples include quinacridone organic pigments such as CI Pigment Red 122 or CI Pigment Violet 19, diketopyrrolopyrrole organic pigments such as CI Pigment Red 254 or CI Pigment Orange 73, naphthol organic pigments such as CI Pigment Red 150 or CI Pigment Red 170, perylene organic pigments such as CI Pigment Red 123 or CI Pigment Red 179, azo organic pigments such as CI Pigment Red 144, and phthalocyanine organic pigments such as CI Pigment Blue 15:1, CI Pigment Blue 15:2, CI Pigment Blue 15:3, CI Pigment Blue 15:6, CI Pigment Green 36, and CI Pigment Green 58. Furthermore, the production method of the present invention can be carried out using newly synthesized organic pigments. The above-mentioned organic pigments may be used alone or in combination of two or more.

[0058] In the present invention, it is desirable to use a reaction such as a poor solvent method, an acidic paste method, or an alkaline paste method to mix an organic pigment solution obtained by dissolving an organic pigment, which is a raw material for the target organic pigment particles, in a good solvent with a precipitation solvent such as a poor solvent for precipitating the organic pigment particles from the organic pigment solution, to precipitate the organic pigment particles and obtain organic pigment particles. Alternatively, the organic pigment particles can be produced by pulverizing the organic pigment using a bead mill or other pulverization method.

[0059] The organic pigment particles may be of the same or different types as the organic pigment used as the raw material for the organic pigment particles. For example, when the raw material for the organic pigment particles is CI Pigment Red 254 (hereinafter also referred to as PR254), the organic pigment particles precipitated by mixing a PR254 solution obtained by dissolving PR254 in a good solvent with a precipitation solvent may be particles of PR254. When the raw materials for the organic pigment particles are two or more different organic pigments, the organic pigment particles precipitated by mixing an organic pigment solution obtained by dissolving these organic pigments in a good solvent with a precipitation solvent may be particles of a solid solution of the two or more different organic pigments.

[0060] (Organic pigment solution or precipitation solvent)

[0061] As the precipitation solvent such as poor solvent that is mixed with the good solvent or organic pigment solution that is used to dissolve the above-mentioned organic pigment and makes organic pigment microparticles separate out from the above-mentioned organic pigment solution, as long as it is the solvent that can dissolve or molecularly disperse the above-mentioned organic pigment or can mix with the organic pigment solution and make organic pigment microparticles separate out from the above-mentioned organic pigment solution, there is no particular limitation. For example, water, organic solvent, or a mixed solvent composed of multiple thereof can be enumerated. As the above-mentioned water, tap water, ion exchange water, pure water, ultrapure water, or RO water etc. can be enumerated, and as the organic solvent, alcohol solvent, amide solvent, ketone solvent, ether solvent, aromatic solvent, carbon disulfide, aliphatic solvent, nitrile solvent, sulfoxide solvent, halogen solvent, ester solvent, ionic liquid, carboxylic acid compound, sulfonic acid compound etc. can be enumerated. The above-mentioned solvent can be used alone respectively, or multiple or more can be used in combination. Here, good solvent refers to a solvent that can be a good solvent for organic pigment, and poor solvent refers to a solvent that has a low solubility for organic pigment compared with the good solvent and can be a poor solvent for organic pigment.

[0062] In addition, can in above-mentioned organic pigment solution or precipitation solvent, mix or dissolve alkaline matter or acidic matter and implement.As alkaline matter, can enumerate metal hydroxides such as sodium hydroxide, potassium hydroxide, the such metal alkoxides of sodium methylate, sodium isopropylate, quaternary ammonium hydroxides such as tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide, and amine compounds such as triethylamine, 2-diethylaminoethanol, diethylamine etc.As acidic matter, can enumerate mineral acids such as aqua regia, hydrochloric acid, nitric acid, nitrous nitric acid, sulfuric acid, oleum, chlorosulfuric acid, organic acids such as formic acid, acetic acid, chloroacetic acid, dichloroacetic acid, oxalic acid, trifluoroacetic acid, trichloroacetic acid.These alkaline matter or acidic matter both can mix with various solvents and implement as mentioned above, also can use separately respectively.

[0063] The method for producing an organic pigment composition of the present invention controls the diffuse reflectance of organic pigment fine particles and controls brightness, which is one of the characteristics of a color filter obtained using the organic pigment composition containing at least the organic pigment fine particles.

[0064] The organic pigment composition of the present invention contains at least a powder of organic pigment particles, a dispersion obtained by dispersing the organic pigment particles in a solvent serving as a liquid dispersion medium, or a dispersion obtained by dispersing the organic pigment particles in a solid such as glass or resin. The organic pigment particles used in the color filter of the present invention preferably have a primary particle size of 200 nm or less, and more preferably have a primary particle size of 100 nm or less.

[0065] When the organic pigment composition is the organic pigment particle dispersion obtained by dispersing organic pigment particles in the solvent as a liquid dispersion medium, a liquid dispersion medium is used as a dispersion medium. As a liquid dispersion medium, an organic solvent is preferably used, and alcohol solvents such as methanol, ethanol, isopropanol can be enumerated, polyol solvents such as propylene glycol, ethylene glycol, diethylene glycol, glycerol, ester solvents such as ethyl acetate, butyl acetate, aromatic solvents such as benzene, toluene, xylene, ketone solvents such as acetone or methyl ethyl ketone, nitrile solvents such as acetonitrile, etc. are used. From the viewpoint of the dispersibility of the organic pigment particles, an ester solvent is preferably used, more preferably propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether. They can be used alone or in combination with more than two kinds.

[0066] When the organic pigment composition is an organic pigment fine particle dispersion, the content of the organic pigment fine particles in the organic pigment composition is preferably 1.0 to 30.0 wt %, more preferably 5.0 to 20.0 wt %, from the viewpoint of preparing a dispersion liquid for a color filter.

[0067] From the viewpoint of forming a dispersion liquid for color filters, the content of the liquid dispersion medium in the organic pigment composition is preferably 70.0 to 99.0 wt %, more preferably 80.0 to 95.0 wt %.

[0068] In the present invention, when the organic pigment composition is an organic pigment fine particle dispersion, the organic pigment fine particles can be added to a liquid dispersion medium and dispersed to obtain the organic pigment fine particle dispersion. The dispersion method and the disperser used are not particularly limited, and the dispersion can be performed using the same apparatus as used for preparing the various solutions and solvents of the present invention.

[0069] Furthermore, a dispersant may be added to the organic pigment composition as needed. The dispersant is not particularly limited, and examples thereof include resin-type dispersants and surfactant-type dispersants. Among these, resin-type dispersants are preferred for preparing an organic pigment composition for evaluating color filter characteristics, from the perspective of fully exerting the pigment dispersion effect and the pigment reaggregation inhibition effect. The resin-type dispersant is not particularly limited, and examples thereof include: oily resin-type dispersants such as polyurethane, polyester, unsaturated polyamide, phosphate ester, polycarboxylic acid and its amine salts, ammonium salts, alkylamine salts, polycarboxylates, hydroxyl-containing polycarboxylates, polysiloxanes, and modified polyacrylates; water-soluble polymers such as alginics, polyvinyl alcohol, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, polyvinyl pyrrolidone, and gum arabic; resins containing olefinic double bonds such as styrene-acrylic resin, styrene-methacrylic resin, styrene-acrylic acid-acrylate resin, styrene-maleic acid resin, styrene-maleic acid ester resin, methacrylic acid-methacrylate resin, acrylic acid-acrylate resin, isobutylene-maleic acid resin, ethylene-ester resin, and rosin-modified maleic acid resin; and aqueous resin-type dispersants such as amine resins such as polyacrylamide, polyvinylamine, and polyethyleneimine.

[0070] Various resin-type dispersants are commercially available. Specific examples of commercially available products include: Solspaz 3000, 9000, 13240, 17000, 20000, 24000, 26000, 28000, 32000, 32500, and 41000 (all trade names, manufactured by Lubrizol Japan), Disperbyk-108, 110, 112, 140, 142, 145, 161, 162, 163, 164, 166, 167, 182, 2000, 2001, 2050, 2070, and 2150, and BYK- LPN-"6919, 21116 (all trade names, ビックケミー·Made in Japan), "EFKA-" 4401, 4403, 4406, 4010, 4015, 4046, 4047, 4050, 4055, 4060, 4080, 5064, 5207, 5244 (all trade names, EFKA Examples include Ajispall PB821(F), PB822, and PB880 (all trade names, manufactured by Ajinomoto Fine Chemicals Co., Ltd.), Hinokut T-8000 (trade name, manufactured by Kawaken Fine Chemical Co., Ltd.), Desparon PW-36, and Desparon DA-325, 375, and 7301 (all trade names, manufactured by Kusumoto Chemicals). Among resin-type dispersants, those with a weight-average molecular weight of approximately 1,000 to 30,000 are preferred.

[0071] The surfactant-type dispersant is not particularly limited, and examples thereof include anionic surfactants such as naphthalenesulfonic acid formaldehyde condensate salts, aromatic sulfonic acid formaldehyde condensates, polyoxyethylene alkyl phosphates, nonionic surfactants such as polyoxyethylene alkyl ethers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts. Various products of surfactant-type dispersants are also commercially available. Specific examples include "Demore" N, RN, MS, SN-B, "Emargen" 120, 430, "Acetamin" 24, 86, Comin 24P (all trade names, manufactured by Kao Corporation), "Platinum" AL, A208F (all trade names, manufactured by Dai-ichi Kogyo Seiyaku), "Arcade" C-50, T-28, T-50 (all trade names, manufactured by Lion Corporation of Japan), etc.

[0072] The pigment dispersant may be used alone or in combination of two or more. Furthermore, from the perspective of color filter properties, the content of the dispersant in the organic pigment composition relative to the organic pigment fine particles is preferably 1 to 25 parts by weight, more preferably 3 to 20 parts by weight, relative to 100 parts by weight of the organic pigment fine particles.

[0073] Figure 1 1 and 2 show diffuse reflectance spectra at wavelengths of 380 nm to 780 nm measured using powders of fine particles of a red diketopyrrolopyrrole pigment CI Pigment Red 254 produced under the conditions of the respective Examples as Examples 1, 2, 3 and 7 of the present invention.

[0074] In the present invention, the brightness of a color filter produced using the organic pigment particles can be controlled by controlling the ratio of the area of ​​the diffuse reflectance of the organic pigment particles in the target wavelength range to the total area of ​​the diffuse reflectance across the entire measurement wavelength range (wavelengths of 380 nm to 780 nm) (area ratio of diffuse reflectance in the target wavelength range: DiR [%]). More specifically, in the present invention, the higher the ratio of the area of ​​the diffuse reflectance of the organic pigment particles in the target wavelength range to the total area of ​​the diffuse reflectance across the entire measurement wavelength range (wavelengths of 380 nm to 780 nm) (area ratio of diffuse reflectance in the target wavelength range: DiR [%]), the higher the brightness of the color filter produced using the organic pigment particles. Here, the diffuse reflectance area refers to the diffuse reflectance at a measurement wavelength of 380 nm to 780 nm, the integrated value of the diffuse reflectance across the entire measurement wavelength range, or target wavelength range.

[0075] For example, assuming that PR254 is used as the red pigment for the color filter, the brightness of the color filter made using the organic pigment particles can be controlled by controlling the ratio of the area of ​​the diffuse reflectance of the organic pigment particle powder at the wavelength of 620 to 750 nm, which is important for the red filter, to the total area of ​​the diffuse reflectance in the entire measurement wavelength range (wavelength of 380 nm to 780 nm).

[0076] about Figure 1 The ratio of the diffuse reflectance area at wavelengths of 620 to 780 nm of the PR254 fine particles obtained in each of the Examples shown in FIG1 to the total diffuse reflectance area over the entire measurement wavelength range (wavelengths of 380 to 780 nm) is 75.94% for Example 1, 75.27% for Example 2, 74.94% for Example 3, and 70.01% for Example 7. Taking the brightness of Example 7 as a reference of 100, the brightness of Example 1 is 128.00, that of Example 2 is 127.80, and that of Example 3 is 127.33. This indicates that the higher the ratio of the diffuse reflectance area at wavelengths of 620 to 750 nm, which is important for red filters, to the total diffuse reflectance area over the entire measurement wavelength range (wavelengths of 380 to 780 nm), the higher the brightness of the color filter can be. In addition, the ratio of the area of ​​the diffuse reflectance at a wavelength of 620 to 750 nm of the PR254 fine particles produced under the conditions of each example, including other examples described later, to the total area of ​​the diffuse reflectance in the entire measurement wavelength range of the diffuse reflectance spectrum at a wavelength of 380 to 780 nm (area ratio of the diffuse reflectance in the target wavelength range: DiR [%]) is shown in FIG. Figure 2 .like Figure 2 As shown, the higher the ratio of the diffuse reflectance area at the wavelength of 620 to 750 nm, which is important for the red filter, to the total area of ​​the diffuse reflectance in the entire measurement wavelength range (wavelength of 380 nm to 780 nm), the higher the brightness of the color filter can be controlled.

[0077] Thus, when the pigment used for the color filter is a red pigment, the target wavelength range is 620-750 nm. By controlling the ratio of the area of ​​diffuse reflectance of the organic pigment fine particles at wavelengths of 620-750 nm, which are important for red filters, to the total area of ​​diffuse reflectance across the entire measurement wavelength range (380-780 nm), the brightness of the color filter produced using the organic pigment fine particles can be controlled. Similarly, when the pigment used for the color filter is a blue pigment, the target wavelength range is 450-495 nm. By controlling the ratio of the area of ​​diffuse reflectance of the organic pigment fine particles at wavelengths of 450-495 nm, which are important for blue filters, to the total area of ​​diffuse reflectance across the entire measurement wavelength range (380-780 nm), the brightness of the color filter produced using the organic pigment fine particles can be controlled. When the pigment used for the color filter is a green pigment, the target wavelength range is 495 to 570 nm. By controlling the ratio of the area of ​​the diffuse reflectance of the organic pigment particle powder at the wavelength of 495 to 570 nm, which is important for the green filter, to the total area of ​​the diffuse reflectance of the entire measurement wavelength range (wavelength of 380 nm to 780 nm), the brightness of the color filter made using the organic pigment particles can be controlled.

[0078] Furthermore, when the organic pigment particles are red pigment particles, the ratio of the area of ​​diffuse reflectance in the target wavelength range of the organic pigment particle powder to the total area of ​​diffuse reflectance in the entire measurement wavelength range (wavelength 380nm to 780nm) (area ratio of diffuse reflectance in the target wavelength range: DiR [%]) is preferably 67% or more, more preferably 71% or more, and even more preferably 76% or more. When the organic pigment particles are blue pigment particles, this ratio is preferably 26% or more, more preferably 30% or more, and even more preferably 32% or more. When the organic pigment particles are green pigment particles, this ratio is preferably 46% or more, more preferably 51% or more, and even more preferably 52% or more.

[0079] For each color of organic pigment particle powder, the ratio of the area of ​​diffuse reflectance in the target wavelength range to the total area of ​​diffuse reflectance in the entire measurement wavelength range (wavelength 380nm to 780nm) (area ratio of diffuse reflectance in the target wavelength range: DiR[%]) is less than 71% for red, less than 30% for blue, and less than 51% for green. The brightness of the color filter may be reduced for the reasons described below. Therefore, when a high-brightness color filter is required, values ​​above the above values ​​are preferably used.

[0080] It should be noted that in currently known color filter technologies, filters for various colors, such as red, blue, and green, employ organic pigment particles not only of the primary color of the target filter but also of a different color (e.g., a complementary color). This technology can also be applied to the present invention, and color filters can be manufactured using organic pigment particles of different colors in addition to the primary color. It should be noted that the amount of organic pigment particles of different colors is generally preferably less than the amount of organic pigment particles of the primary color.

[0081] In the present invention, diffuse reflectance refers to the ratio of diffusely reflected light (scattered light) to incident light of a specific wavelength. It is the reflected light minus the specularly reflected component. Therefore, diffuse reflectance is considered a parameter that affects visual perception and the color actually detected by a detector. In color filters, color is developed by allowing light of a target wavelength to pass through a coating of an organic pigment composition. Therefore, conventionally, the transmission spectrum of the coating or dispersion of the organic pigment composition has been largely studied. However, the transmittance obtained by measuring the transmission spectrum only indicates the extent to which incident light of a specific wavelength passes through the coating, making it an insufficient indicator for evaluating color filter properties. There is a correlation between the diffuse reflectance of organic pigment particles and the brightness of a color filter coated with a dispersion of the organic pigment particles. While the details are uncertain, the present applicants believe that, for example, in color filters used in liquid crystal displays, when backlight passes through the color filter, only a specific color is transmitted depending on the organic pigment composition contained in the coating. Furthermore, diffuse reflection from the pigment of a specific color itself controls brightness, which is an indicator of the brightness of the color filter. However, when diffusely reflecting light other than the target wavelength, that is, when displaying a color other than the target color, the color filter may mix with other colors, causing a problem of perception, which is not preferred. For example, when displaying diffuse reflection of light other than the target wavelength of 620 to 750 nm with red as the target, the color rendering of light other than red is perceived, causing changes in color tone and resulting in reduced brightness. In the present invention, it is believed that brightness can be controlled by controlling the ratio of the wavelength range of the target color to the entire measurement wavelength range of the organic pigment particle powder, that is, the ratio of the area of ​​the diffuse reflectance of the organic pigment particle powder in the target wavelength range to the total area of ​​the diffuse reflectance of the entire measurement wavelength range (wavelength 380 nm to 780 nm) (area ratio of diffuse reflectance in the target wavelength range: DiR [%]).

[0082] The measuring method of diffuse reflectance is not particularly limited as long as it is a method for measuring the diffuse reflectance spectrum of organic pigment particles. As a measuring device, if given as an example, ultraviolet visible near infrared spectrophotometer V-750, V-770, V-7080, V-7090 (above, Japan Spectrophotometer), UV-3600, Solid-Spec3700 (above, Shimadzu Corporation) etc. can be enumerated. In addition, in the present invention, in order to eliminate the influence of the dispersant or dispersion medium contained in the organic pigment composition, as the simplest method, the method of the diffuse reflectance spectrum of the powder of the organic pigment particles is preferably measured. The correlation between the diffuse reflectance of the organic pigment particles and the brightness of the color filter of the coating film made using the organic pigment particle dispersion has been found. By controlling the diffuse reflectance of the organic pigment, the high brightness of the color filter can be realized, and the present invention has been completed.

[0083] The organic pigment particles of the present invention can have at least a portion of their surface covered with an oxide. For example, covering at least a portion of the surface of the organic pigment particles with an oxide such as silicon oxide has the advantage of increasing the diffuse reflectance and brightness of the color filter in the present invention. When covering at least a portion of the surface of the organic pigment particles with an oxide such as silicon oxide, it is preferred that the oxide such as silicon oxide contains an amorphous component from the perspective of diffuse reflectance and brightness in the color filter characteristics. This is because covering at least a portion of the surface of the organic pigment particles with a crystalline oxide may increase the reflectance of light outside the target wavelength due to, for example, effects on the refractive index. However, the method for controlling the diffuse reflectance of the organic pigment particles of the present invention is not particularly limited. The diffuse reflectance of the organic pigment particles can be controlled by, for example, adjusting the pH during precipitation of the organic pigment particles by mixing a fluid containing an organic pigment solution with a fluid containing a precipitation solvent, or by surface treating the organic pigment particles with an oxide such as silicon oxide, a polymer, or a resin, or by modifying the crystal form, crystallinity, particle size, or particle size distribution of the organic pigment particles. The diffuse reflectance of the target color characteristics of the organic pigment particles can be controlled.

[0084] The pH adjustment during the precipitation of the organic pigment particles can be achieved by including a pH adjusting agent in at least one of the various solutions or solvents of the present invention, or by varying the flow rate when mixing the fluid containing the organic pigment solution with the fluid containing the precipitation solvent. When at least a portion of the surface of the organic pigment particles is coated with an oxide such as silicon oxide, the pH can be adjusted by varying the flow rate when mixing the fluid containing the organic pigment solution with the fluid containing the precipitation solvent, or by varying the flow rate when mixing the resulting mixed fluid with a fluid containing a treatment substance for generating oxides from the raw materials of the oxides described later. The pH adjusting agent can be the alkaline or acidic substances described above, or salts of the acidic or alkaline substances can be used.

[0085] In particular, when precipitating organic pigment particles covered with silicon oxide, it is advantageous to set the pH of the mixed fluid after precipitation to 5.0 to 12, preferably 6.5 to 10, and more preferably 6.5 to 8, from the perspective of improving diffuse reflectance. A pH below 5.0 hinders precipitation of silicon oxide, potentially resulting in insufficient coverage of the organic pigment particles. Furthermore, a pH above 12 may cause the precipitated silicon oxide to redissolve, potentially resulting in insufficient coverage of the organic pigment particles.

[0086] Examples of oxides such as silicon oxide that cover at least a portion of the surface of the organic pigment particles include, in addition to silicon oxide, aluminum oxides such as alumina (Al2O3), zirconium oxides such as zirconium oxide (ZrO2), and organic oxides such as organopolysiloxanes. Examples of polymers and resins that cover at least a portion of the surface of the organic pigment particles are not particularly limited, but examples thereof include aqueous polymers such as polyethylene glycol, polyvinyl alcohol, polyvinyl pyrrolidone, sodium polyacrylate, celluloses such as hydroxypropylmethylcellulose, sodium alginate, sodium carboxymethylcellulose, xanthan gum, carrageenan, pullulan, and gelatin.

[0087] When the oxide covering at least a portion of the surface of the organic pigment particles is an inorganic oxide, a coupling agent may be present between the surface of the organic pigment particles and the oxide. In order to improve the affinity between the two, a coupling agent is preferably present between the two. When silicon oxide is used as the oxide, a silane coupling agent is used as the coupling agent. The silane coupling agent is not particularly limited as long as it has two or more different reactive groups in the molecule. Examples include 3-aminopropyltriethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, 3-(2-aminoethylamino)propyldimethoxymethylsilane, 3-(2-aminoethylamino)propyltriethoxysilane, 3-aminopropyldimethoxymethylsilane, bis[3-(trimethoxysilyl)propyl]amine, 3-aminopropyldiethoxymethylsilane, [3-(N,N-dimethylamino)propyl]trimethoxysilane, 3-aminopropyltrimethoxysilane, and trimethoxy[3-(methylamino)propyl]silane. When aluminum oxide is used as the oxide, aluminum acetoalkoxydiisopropoxide and aluminum acetylacetonate can be used as the coupling agent. When zirconium oxide is used as the oxide, zirconium acetylacetonate and zirconium stearate can be used as the coupling agent. The coupling agent and the organic pigment particles are combined not only due to the affinity of the lipophilic group, but also because the organic pigment particles and the coupling agent can form a direct bond through reaction. The coupling agent and the oxide are bonded through dehydration condensation of the sol-gel method.

[0088] When a portion of the surface of the organic pigment particles is covered with an oxide in a liquid phase method, at least one of the organic pigment solution, the precipitation solvent, and another fluid different from both the organic pigment solution and the precipitation solvent may contain a raw material for the oxide, a treatment substance for generating an oxide from the raw material for the oxide, a coupling agent, etc. As the raw material for the oxide, when the oxide is silicon oxide, inorganic compounds such as silicon oxides, hydroxides, chlorides, or salts, and hydrates thereof, and organic compounds such as silicon alkoxides or acetylacetonates, and hydrates thereof, may be mentioned. Although not particularly limited, examples thereof include phenyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-trifluoropropyltrimethoxysilane, methacryloxypropyltriethoxysilane, tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), and oligomeric condensates of TEOS, such as ethyl silicate 40, tetraisopropylsilane, tetrapropoxysilane, tetraisobutoxysilane, tetrabutoxysilane, and the like. Furthermore, other siloxane compounds, bis(triethoxysilyl)methane, 1,9-bis(triethoxysilyl)nonane, diethoxydichlorosilane, triethoxychlorosilane, and the like may also be used. When the oxide is aluminum oxide, its raw materials include inorganic compounds such as aluminum oxides, hydroxides, chlorides or salts and their hydrates, or organic compounds such as aluminum alkoxides or acetylacetonates and their hydrates. There are no special restrictions, and examples include aluminum compounds such as aluminum hydroxide, aluminum isopropylate, and aluminum butoxide. In addition, when the oxide is zirconium oxide, its raw materials include inorganic compounds such as zirconium oxides, hydroxides, chlorides or salts and their hydrates, or organic compounds such as zirconium alkoxides or acetylacetonates and their hydrates. There are no special restrictions, and examples include zirconium compounds such as zirconium isopropylate and zirconium butoxide. In addition, as a treatment substance for generating an oxide from the raw material of the oxide, an alkaline substance is preferred, and there are no special restrictions, and examples include metal hydroxides such as sodium hydroxide and potassium hydroxide, metal carbonates such as sodium carbonate and potassium carbonate, and amine compounds such as triethylamine, 2-diethylaminoethanol, and diethylamine, and ammonia. Examples include quaternary ammonium hydroxides such as tetrabutylammonium hydroxide and benzyltrimethylammonium hydroxide. Other fluids different from both the organic pigment solution and the precipitation solvent may contain the aforementioned water, organic solvent, or a mixed solvent composed of multiple thereof.

[0089] It should be noted that the applicant's prior application PCT / JP2016 / 77378 proposed an invention involving organic pigment particles whose surface is partially covered with an oxide. However, regardless of the presence or absence of an oxide coating, the organic pigment particles used to implement the present invention are as described above. In other words, the present invention can be implemented using only the organic pigment particles of the invention of the prior application, or it can be implemented using other organic pigment particles in combination, or it can be implemented using only other organic pigment particles. In addition, there is no particular limitation on the crystalline structure of the oxide coating of the organic pigment particles of the invention of the prior application. However, when implementing the present invention, various substances can be used to implement the oxide coating, and highly crystalline substances, amorphous substances, or a mixture of the two can be used. The present invention is based on new knowledge about the relationship between the diffuse reflectance of organic pigment particles and the brightness of the color filter obtained therefrom. The new knowledge about this relationship can be applied regardless of the structure of the organic pigment particles themselves.

[0090] When at least a portion of the surface of the organic pigment particles is covered with an oxide such as silicon oxide, the covered organic pigment particles only need to have a controlled diffuse reflectance. Preferably, the organic pigment particles are organic pigment particles in which a plurality of organic pigment particles are not agglomerated, and at least a portion of the surface of a single organic pigment particle is covered with an oxide such as silicon oxide. However, the organic pigment particles may also be organic pigment particles in which at least a portion of the surface of an agglomerate of a plurality of organic pigment particles is covered with an oxide such as silicon oxide.

[0091] When the organic pigment particles after coating are organic pigment particles in which at least a portion of the surface of a single organic pigment particle is coated with an oxide such as silicon oxide, the primary particle size of the organic pigment particles after coating is preferably not less than 100.5% and not more than 190% of the primary particle size of the organic pigment particles. If the oxide coating of the organic pigment particles is too thin, the effect of controlling the diffuse reflectance of the organic pigment particles after coating may not be achieved. Therefore, the primary particle size of the organic pigment particles after coating is preferably not less than 100.5% of the primary particle size of the organic pigment particles before coating. If the oxide coating of the organic pigment particles is too thick, the effect of controlling the diffuse reflectance of the organic pigment particles after coating may not be achieved. Therefore, the primary particle size of the organic pigment particles after coating is preferably not more than 190% of the primary particle size of the organic pigment particles before coating.

[0092] Furthermore, organic pigment particles whose aggregates exceed a certain size and whose surfaces are at least partially covered with an oxide such as silicon oxide are less effective in controlling diffuse reflectance than organic pigment particles whose surfaces are at least partially covered with an oxide such as silicon oxide. Therefore, the particle size of the organic pigment particles after covering at least a portion of the aggregate surface with an oxide such as silicon oxide is preferably 190% or less of the aggregate diameter. Aggregates exceeding a certain size here refer, for example, to aggregates exceeding 500 nm in size. Furthermore, if the coverage of the organic pigment particles with an oxide such as silicon oxide is too thin, the effect of controlling diffuse reflectance of the covered organic pigment particles may not be achieved. Therefore, the particle size of the covered organic pigment particles is preferably 100.5% or more of the aggregate diameter. The aggregate diameter refers to the distance between the maximum peripheries of the aggregates formed by the plurality of organic pigment particles.

[0093] When the organic pigment particles are coated, if the oxide coating at least a portion of the surface of the organic pigment particles is silicon oxide, the organic pigment particles coated with silicon oxide are subjected to infrared absorption spectroscopy (FT-IR) and X-ray diffraction (XRD) measurements. The FT-IR measurement shows a peak derived from silicon oxide, while the XRD measurement shows no peak derived from silicon oxide, confirming that the oxide is amorphous. Furthermore, scanning transmission electron microscopy (hereinafter also referred to as STEM) observation of the coated organic pigment particles confirms the absence of a lattice derived from silicon oxide, confirming that the oxide is amorphous.

[0094] The coating state of the organic pigment fine particles can be confirmed using an electron microscope such as a transmission electron microscope (hereinafter also referred to as TEM) or a STEM.

[0095] In the present invention, organic pigment particles for controlling diffuse reflectance can be produced using the forced thin film type microreactor disclosed as a fluid processing device in Patent Document 1, but are not limited thereto. Examples include methods for producing organic pigment particles using other types of microreactors, methods for producing organic pigment particles by conducting a dilute reaction in a batch container, and methods for producing organic pigment particles by pulverizing an organic pigment using a bead mill or other pulverization method. For coating at least a portion of the surface of the organic pigment particles with an oxide such as silicon oxide, examples include methods for producing the organic pigment particles using a first microreactor and then coating at least a portion of the surface of the organic pigment particles with an oxide such as silicon oxide using a second microreactor; methods for producing the organic pigment particles by conducting a dilute reaction in a batch container and then coating at least a portion of the surface of the organic pigment particles with an oxide such as silicon oxide using a dilute reaction; methods for producing the organic pigment particles by a bead mill or other pulverization method and then coating at least a portion of the surface of the organic pigment particles with an oxide such as silicon oxide in a reaction container, and the like. Alternatively, the apparatus and method described in Japanese Patent Application Laid-Open No. 2009-112892, proposed by the applicant of the present application, may be used. Of course, a method for producing organic pigment particles using the aforementioned forced thin-film type microreactor may be used. It should be noted that, in the present invention, organic pigment particles produced by reactions such as the aforementioned lean solvent method, and organic pigment particles in which at least a portion of the surface is covered with silicon oxide, are less susceptible to crystallinity deformation, etc., compared to organic pigment particles produced by pulverizing using a bead mill or the like, and are therefore suitable for improving diffuse reflectance and the brightness of a color filter.

[0096] The coloring composition that can be used for color filters by mixing the organic pigment composition of the present invention contains at least the organic pigment composition, a photosensitive monomer, and a photopolymerization initiator. The coloring composition may also contain a binder resin and an alkali-soluble resin.

[0097] Examples of photosensitive monomers include monofunctional monomers such as carbitol nonylphenyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and carbitol 2-ethylhexyl acrylate; polyfunctional monomers such as (meth)acrylates having two or more ethylenically unsaturated double bonds (e.g., compounds obtained by esterifying multiple hydroxyl groups of a polyol with acrylic acid), urethane (meth)acrylates, (meth)acrylamides, acrylic compounds, and vinyl esters. Examples of photopolymerizers include aromatic ketones, rofenalidone dimer, benzoin, benzoin ethers, and polyhalogens. Examples of photopolymerization initiators include a combination of 4,4'-bis(diethylamino)benzophenone and 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 4-[pN,N-bis(ethoxycarbonylmethyl)-2,6-bis(trichloromethyl)-s-triazine], and 2-methyl-4'-(methylthio)-2-morpholinopropiophenone. These can be used alone or in combination of two or more.

[0098] Examples of the binder resin include acrylic resins, butyral resins, styrene-maleic acid copolymers, chlorinated polyethylene, chlorinated polypropylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymers, polyvinyl acetate, polyurethane resins, polyester resins, vinyl resins, alkyd resins, polystyrene resins, polyamide resins, rubber resins, cyclized rubber resins, celluloses, polyethylene (HDPE, LDPE), polybutadiene, and polyimide resins. Preferred alkali-soluble resins include copolymers of (meth)acrylates and (meth)acrylic acid from the viewpoint of maintaining pigment dispersion in the cured film and improving contrast. Examples of the alkali-soluble resin include copolymers of benzyl (meth)acrylate and (meth)acrylic acid.

[0099] The coloring composition may further contain additives such as a sensitizer, an antioxidant, an ultraviolet absorber, a leveling agent, and a dispersant.

[0100] In the film made using the organic pigment composition, the film made using the coloring composition is also included. The film can be obtained by applying, photocuring, and developing the coloring composition on the substrate for the color filter by a known method, or by applying the organic pigment composition on the substrate by a known method. The film can be subjected to baking treatments such as pre-baking and post-baking. The color filter can be produced by applying, photocuring, and developing the coloring composition on the substrate to obtain a film.

[0101] The method for measuring the brightness of the resulting coating film is not particularly limited. A measuring device such as a spectrophotometer or a spectrocolorimeter can be used. Examples of measuring devices include a spectrocolorimeter (trade name: CM-3700d, manufactured by Konica Minolta).

[0102] By using an organic pigment composition containing organic pigment particles with controlled diffuse reflectance to create a coating film, the brightness of the coating film can be controlled, and the brightness of the color filter can also be controlled. In particular, color filters created using the organic pigment particles of the present invention can achieve both higher diffuse reflectance and higher brightness than color filters using bead mill organic pigment particles. Bead mill organic pigment particles are organic pigment particles created by pulverizing the organic pigment used as a raw material in a bead mill to form microparticles.

[0103] The brightness of a coating film produced using the organic pigment fine particle dispersion of the present invention is evaluated by measuring the diffuse reflectance of the organic pigment fine particle powder and using the relationship obtained through steps (I) to (IV). Steps (I) to (IV) are as follows.

[0104] Step (I): a step of obtaining at least one organic pigment microparticle,

[0105] Step (II): a step of measuring the diffuse reflectance of the powder of the organic pigment fine particles in the wavelength range of 380 to 780 nm,

[0106] Step (III): a step of dispersing the organic pigment particles in a solvent to obtain an organic pigment particle dispersion.

[0107] Step (IV): a step of measuring the brightness of a coating film produced using the organic pigment fine particle dispersion and determining the relationship between the brightness of the coating film and the ratio of the diffuse reflectance area in the target wavelength range to the total diffuse reflectance area in the entire measurement wavelength range.

[0108] The details of steps (I) to (III) have been described above. Regarding step (IV), the measured brightness of the coating film is plotted against the ratio of the area of ​​the diffuse reflectance in the target wavelength range to the total area of ​​the diffuse reflectance in the entire measurement wavelength range (area ratio of diffuse reflectance in the target wavelength range: DiR [%]), calculated from the diffuse reflectance of the organic pigment fine particle powder measured in step (II). This approximate calculation is then performed to determine the relationship between the brightness of the coating film and the area ratio of the diffuse reflectance in the target wavelength range: DiR [%]. According to the present invention, by measuring the diffuse reflectance of the organic pigment fine particle powder, the brightness of a coating film produced using an organic pigment composition can be evaluated. Here, when the organic pigment fine particles are red pigment fine particles, the target wavelength range is 620 to 750 nm; when the organic pigment fine particles are blue pigment fine particles, the target wavelength range is 450 to 495 nm; and when the organic pigment fine particles are green pigment fine particles, the target wavelength range is 495 to 570 nm.

[0109] The brightness of the coating film to be evaluated is a relative value with the brightness of the coating film serving as a reference being 100.

[0110] Example

[0111] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0112] (Examples 1 to 6)

[0113] An organic pigment solution was prepared by dissolving an organic pigment in a good solvent using a high-speed rotary dispersing and emulsifying device, Clear Mix (product name: CLM-2.2S, manufactured by M Technology Co., Ltd.). Specifically, based on the formulation of the organic pigment solution shown in Table 1, the components of the organic pigment solution were weighed, and the mixture was stirred and uniformly mixed for 30 minutes at a preparation temperature of 45°C and a rotor speed of 20,000 rpm using Clear Mix to prepare the organic pigment solution. Separately, based on the formulation of the poor solvent shown in Table 1, the components of the poor solvent for precipitating the organic pigment particles from the organic pigment solution were weighed, and the mixture was stirred and uniformly mixed for 30 minutes using Clear Mix at a preparation temperature of 35°C and a rotor speed of 15,000 rpm to prepare the poor solvent. For the chemical substances listed in Table 1 (including those represented by chemical formulas or abbreviations), ILUGADON L3670HD (manufactured by BASF) was used as PR254, methanol (manufactured by Goodall Corporation) was used as MeOH, dimethyl sulfoxide (manufactured by Kanto Chemical, purity 99.5%) was used as DMSO, sodium methoxide (manufactured by Kanto Chemical) was used as NaOMe, and acetic acid (purity >99.7%, manufactured by Kanto Chemical) was used as acetic acid. Pure water with a pH of 5.89 (29.3°C) and an electrical conductivity of 0.79 μS / cm was used.

[0114] Next, the prepared organic pigment solution and the poor solvent are mixed using the fluid processing device described in Patent Document 1 proposed by the applicant of the present application. Figure 1The fluid treatment device shown in , wherein the opening portion d20 of the second introduction portion is a concentric ring shape surrounding the central opening of the processing surface 2, and the processing surface 2 is an annular disk. Specifically, a poor solvent as liquid A is introduced from the first introduction portion d1 into the processing surfaces 1 and 2, and the processing portion 10 is rotated. While the operation is in progress, an organic pigment solution as liquid B is introduced from the second introduction portion d2 into the processing surfaces 1 and 2, and the organic pigment solution and the poor solvent are mixed in the thin film fluid to precipitate PR254 particles between the processing surfaces 1 and 2. The fluid containing the PR254 particles precipitated between the processing surfaces 1 and 2 (hereinafter also referred to as PR254 particle dispersion) is ejected from the processing surfaces 1 and 2 of the fluid treatment device, and the ejected PR254 particle dispersion is recovered in a container. Table 2 shows the operating conditions of the fluid treatment device. The rotation speed shown in Table 2 is the rotation speed of the processing part 10. The introduction temperature (liquid supply temperature) and introduction pressure (liquid supply pressure) of liquid A and liquid B are measured using a thermometer and a pressure gauge installed in the sealed introduction path (first introduction part d1 and second introduction part d2) passing through the processing surfaces 1 and 2. The introduction temperature of liquid A shown in Table 2 is the actual temperature of liquid A under the introduction pressure in the first introduction part d1. Similarly, the introduction temperature of liquid B is the actual temperature of liquid B under the introduction pressure in the second introduction part d2. In addition, the pH of the ejected liquid is shown in Table 2 together with the pH measurement temperature (temperature [°C]). The pH of the ejected liquid was measured using a pH meter model D-51 manufactured by HORIBA. It is difficult to measure the pH of the mixed fluid immediately after the organic pigment solution and the poor solvent are mixed. Therefore, the pH of the PR254 fine particle dispersion ejected from the device and recovered in the container was measured at room temperature.

[0115] [Table 1]

[0116]

[0117] [Table 2]

[0118]

[0119] Dry powder and wet cake samples were prepared from a dispersion of PR254 fine particles ejected from a fluid processing device and recovered in a container. The preparation method followed conventional methods for this type of treatment. The PR254 fine particles in the dispersion were allowed to settle, the supernatant removed, and then the PR254 fine particles were washed by repeating five cycles of washing with 100 parts by weight of pure water and settling the organic pigment fine particles. A portion of the resulting wet cake of PR254 fine particles was dried at 25°C for 19 hours to obtain a dry powder. The residue was used as a wet cake sample.

[0120] (Example 7)

[0121] As Example 7, the PR254 raw material (Ilgadin Red L3670HD (manufactured by BASF) used in the production of PR254 fine particles in Examples 1 to 6 was pulverized using a bead mill to the same particle size as in Examples 1 to 6 to produce PR254 fine particles.

[0122] A portion of the wet cake sample of the washed PR254 fine particles obtained in Examples 1-6 was dispersed in an aqueous solution containing 0.05 wt% of the surfactant Neogen RK (manufactured by Daiichi Kogyo Seiyaku), dropped onto a collodion film, and dried. The dried product was used as a sample for TEM (transmission electron microscopy) observation. The primary particle size of the PR254 fine particles was measured using a JEM-2100 transmission electron microscope (manufactured by JEOL). The observation conditions were an accelerating voltage of 80 kV and an observation magnification of 10,000x or greater. The particle sizes (D) listed in Table 2 are primary particle sizes, calculated as the distance between the maximum peripheries of the particles (for the Examples described below in which at least a portion of the surface of the organic pigment fine particles is coated with an oxide, this is the distance between the maximum peripheries of the particles, including the coating layer). The average values ​​for the measurements of 100 particles are shown. Furthermore, the PR254 microparticles obtained in Example 7 were dispersed in an aqueous solution containing 0.05 wt% of the surfactant Neogen RK (manufactured by Dai-ichi Kogyo Seiyaku), dropped onto a collodion membrane and dried. The dried product was used as a sample for TEM (transmission electron microscope) observation. TEM observation was performed in the same manner as in Examples 1 to 6 to measure the primary particle size of the PR254 microparticles and calculate the particle size (D).

[0123] (Diffuse reflectance spectrum)

[0124] The diffuse reflectance spectrum was measured using an ultraviolet-visible near-infrared spectrophotometer (product name: SolidSpec-3700, manufactured by Shimadzu Corporation). The measurement was performed under the conditions of a measurement range of 380 to 780 nm, a sampling frequency of 2.0 nm, a medium measurement speed, and a dual-beam photometric measurement method, excluding specular reflection. In addition, a standard white plate (product name: Spectralon (trademark), manufactured by Labsphere) was used for background measurement (baseline setting) when measuring powders. The diffuse reflectance spectrum was measured using the dry powder of the organic pigment particles obtained in each example.

[0125] (Preparation of samples for brightness measurement)

[0126] In order to measure the brightness as a color filter, organic pigment fine particle dispersions and cured films were prepared using the PR254 fine particles obtained in Examples 1 to 7. Specifically, 20 parts by weight of the dry powder of the PR254 fine particles obtained in Examples 1 to 7, 25.92 parts by weight of "BYK-LNP-6919" ​​(solid content concentration 60.9% by weight, manufactured by Bick Chemie Co., Ltd.) as a resin-type dispersant, 33.75 parts by weight of the vinyl ester resin "Libokishi SPC-2000" (solid content concentration 35% by weight, manufactured by Showa Denko) as a resin-type dispersant, and 110.53 parts by weight of propylene glycol monomethyl ether acetate (hereinafter also referred to as "PGMEA") as a dispersion medium were dispersed using a Clear Mix double-action stirrer (CLM-2.2 / 3.7W, manufactured by M Technology Co., Ltd.) at a rotor speed of 20,000 rpm and a screen speed of 18,000 rpm for 1 hour to obtain an organic pigment fine particle dispersion. The obtained organic pigment fine particle dispersion was applied to a glass substrate using a spin coater and then heated and dried (prebaked) at 90°C in a dryer for 2 minutes and 30 seconds to obtain a coating film. Furthermore, the obtained coating film was heated and dried (postbaked) at 230°C in a dryer for 30 minutes and cooled to obtain a colored glass plate (color filter).

[0127] The brightness of the colored glass substrates obtained in Examples 1 to 7 was measured as follows. The colored glass substrates were placed in a spectrocolorimeter (trade name: CM-3700d, manufactured by Konica Minolta) and the transmission chromaticity along the XYZ coordinate axes at 2° under illuminant C was measured. The Y value at this time was used as the brightness.

[0128] Figure 1 The diffuse reflectance spectra at wavelengths of 380 nm to 780 nm measured using the powders of PR254 microparticles prepared in Examples 1, 2, 3, and 7 are shown in FIG. Figure 1 Based on the measurement results shown in Table 2, the ratio of the area of ​​diffuse reflectance at a wavelength of 620 to 750 nm to the total area of ​​diffuse reflectance in the entire measurement wavelength range (area ratio of diffuse reflectance in the target wavelength range: DiR [%]) was calculated and shown in Table 2 along with the brightness of the colored glass substrate. The brightness of the colored glass substrates of Examples 1 to 7 in Table 2 is expressed as a relative value with the brightness of the colored glass plate of Example 7 as a reference (100). The same measurement was also performed on the PR254 fine particles obtained in Examples 4 to 6.

[0129] (Examples 8 to 10)

[0130] As Examples 8 to 10, examples are shown in which at least a portion of the surface of PR254 fine particles is covered with silicon oxide using the fluid processing apparatus described in Patent Document 1 proposed by the applicant of the present application.

[0131] Using Clear Mix (product name: CLM-0.8S, manufactured by M Technology Co., Ltd.), a first fluid (also referred to as liquid A) and a second fluid (also referred to as liquid B) were prepared. Specifically, based on the recipe of liquid A shown in Table 3, the components of liquid A were weighed, and Clear Mix was used to stir and evenly mix them at a preparation temperature of 25°C and a rotor rotation number of 10,000 rpm for 30 minutes to prepare liquid A. In addition, based on the recipe of liquid B shown in Table 3, the components of liquid B were weighed, and Clear Mix was used to stir and evenly mix them at a preparation temperature of 40°C and a rotor rotation number of 20,000 rpm for 30 minutes to prepare liquid B. In addition, the third fluid (also referred to as liquid C) shown in Table 3 was used directly without modulation. In Examples 8 to 10, the first fluid is a poor solvent for precipitating an organic pigment, the second fluid is an organic pigment solution obtained by dissolving an organic pigment in a good solvent, and the third fluid is a fluid containing a treatment substance that generates an oxide from an oxide raw material.

[0132] For the chemical substances listed in Table 3 (including those represented by chemical formulas or abbreviations), acetic acid (purity >99.7%, manufactured by Kanto Chemical) was used as acetic acid, tetraethyl orthosilicate (manufactured by Wako Pure Chemical Industries, Ltd.) was used as TEOS, Irugadin L3670HD (manufactured by BASF) was used as PR254, 3-aminopropyldiethoxymethylsilane (purity >97.0%, manufactured by Tokyo Chemical Industry Co., Ltd.) was used as 3-aminopropyldiethoxymethylsilane, 40% BTMA in methanol was used as benzyltrimethylammonium hydroxide, 40% in methanol (manufactured by Tokyo Chemical Industry Co., Ltd.), dimethyl sulfoxide (manufactured by Kishida Chemical Co., Ltd.) was used as DMSO, and ammonia (manufactured by Kishida Chemical Co., Ltd.) was used as 28% ammonia aqueous solution. Pure water having a pH of 5.89 (29.3°C) and an electrical conductivity of 0.79 μS / cm was used as pure water.

[0133] [Table 3]

[0134]

[0135] Next, the first fluid, the second fluid, and the third fluid are mixed and prepared using the fluid processing device described in Patent Document 1. Figure 1The fluid processing device shown in the present invention further includes a third introduction section (paragraph 0082 of the publication) in addition to the first introduction section d1 and the second introduction section d2. The opening d20 of the second introduction section d2 is arranged upstream of the opening of the third introduction section d3. The opening d20 of the second introduction section and the opening of the third introduction section are both concentric ring-shaped, surrounding the central opening of the processing surface 2, which is an annular disk. Specifically, liquid A, which is the first fluid, is introduced from the first introduction section d1 into the processing surface 1 and 2. The processing section 10 is operated at a rotation speed of 1130 rpm. At the same time, liquid B, which is the second fluid, is introduced from the second introduction section d2 into the processing surface 1 and 2. Liquid A and liquid B are mixed in the thin film fluid to cause PR254 particles to precipitate between the processing surfaces. Next, liquid C, which is the third fluid, is introduced from the third introduction section into the processing surface 1 and 2. The fluid containing the PR254 particles that have previously precipitated in the thin film fluid is mixed with liquid C. In a thin film fluid, silicon oxide is precipitated on the surface of the previously precipitated PR254 particles, and a fluid containing the PR254 particles covered with silicon oxide (hereinafter also referred to as a dispersion of PR254 particles covered with silicon oxide) is ejected from between the processing surfaces 1 and 2 of the fluid processing device and recovered in a container. Table 4 shows the operating conditions of the fluid processing device. The inlet pressure and inlet temperature of the first to third fluids, as well as the pH of the ejected liquid, were measured using the same method as in Examples 1 to 6. Since it is difficult to measure the pH of the fluid containing the PR254 particles and the fluid containing the treatment material that generates oxides from the raw materials of the oxides as the third fluid immediately after mixing, the pH of the dispersion of PR254 particles covered with silicon oxide ejected from the device and recovered in the container was measured at room temperature.

[0136] The silicon oxide-coated PR254 fine particles prepared in Examples 8 to 10 were subjected to FT-IR measurement, XRD measurement, and STEM observation. As a result, in the FT-IR measurement, the silicon oxide-coated PR254 fine particles at 1100 cm -1 A peak derived from silicon oxide was observed in the vicinity, but no peak derived from silicon oxide was observed in XRD measurement. Figure 7 The IR measurement results of the silicon oxide-coated PR254 particles obtained in Example 10 are shown, as well as the amorphous silicon oxide (silicon dioxide (precipitated, amorphous), 3N, purity 99.9%, manufactured by Kanto Chemical) and the PR254 used as a raw material (Ilgadin Red L3670HD (manufactured by BASF)) ( Figure 7IR measurement results of the PR254 microparticles (indicated as "raw material powder" in the figure). In addition, STEM observation confirmed the absence of a lattice derived from silicon oxide. The above results confirm that the silicon oxide of the PR254 microparticles covered with silicon oxide is amorphous. IR measurement was performed using a Fourier transform infrared spectrophotometer FT / IR-4100 (manufactured by JASCO Corporation) under the following measurement conditions: ATR method with a resolution of 4.0 cm -1 , with a cumulative number of 1024. Furthermore, X-ray diffraction (XRD) measurements were performed using a powder X-ray diffractometer, EMPYREAN (manufactured by SPECTRIC CORPORATION, PANalytical Division), with the following measurement conditions: measurement range: 10 to 100 [°2θ], Cu counter cathode, tube voltage 45 kV, tube current 40 mA, and scanning speed 0.3° / min.

[0137] Furthermore, elemental mapping and quantification using STEM were performed on the silicon oxide-coated PR254 microparticles produced in Examples 8 to 10 to confirm the coverage of the PR254 microparticles with silicon oxide. The mapping and quantification of elements contained in the silicon oxide-coated PR254 microparticles by STEM observation and STEM-EDS analysis were performed using an atomic resolution electron microscope JEM-ARM200F (manufactured by JEOL) equipped with an energy dispersive X-ray analyzer Centurio (manufactured by JEOL), using a beam with a diameter of 0.2 nm.

[0138] In a single particle observed in a dark field image (HADDF image), the distribution of silicon (Si) and oxygen (O) throughout the particle was observed, and nitrogen (N) derived from PR254 was observed to be distributed in a narrower range than the distribution of silicon (Si) and oxygen (O). Based on this, it is believed that the silicon oxide-coated PR254 particles obtained in Examples 8 to 10 were entirely covered with silicon oxide.

[0139] Washing of the silicon oxide-coated PR254 fine particles, measurement of the primary particle size and calculation of the particle size (D) of the silicon oxide-coated PR254 fine particles, measurement of the diffuse reflectance of the silicon oxide-coated PR254 fine particles and calculation of the area ratio of the diffuse reflectance in the target wavelength range (DiR [%), preparation of an organic pigment fine particle dispersion, preparation of a coating film, and measurement and evaluation of the brightness of the colored glass substrate were performed in the same manner as in Examples 1 to 6 or 7. The results are shown in Table 4.

[0140] [Table 4]

[0141]

[0142] (Examples F-1 and F-2)

[0143] In Example F-1, PR254 microparticles were prepared under the same conditions as in Example 1 except that the apparatus described in Japanese Patent Application Laid-Open No. 2009-112892 and the mixing and reaction method of Solution A and Solution B were used. Figure 1 The apparatus described in , wherein the inner diameter of the stirring tank was 420 mm, the gap between the outer end of the stirrer and the inner circumference of the stirring tank was 1 mm, and the rotation speed of the stirring blade was the same as the rotation speed of the processing unit 10 of the fluid treatment device used in Example 1 (1000 rpm). In addition, liquid A was introduced into the stirring tank, and liquid B was added to the thin film formed by liquid A pressed against the inner circumference of the stirring tank to mix and react. Table 5 shows the operating conditions of the apparatus.

[0144] In Example F-2, PR254 particles covered with silicon oxide were prepared under the same conditions as in Example 8 except that the apparatus and the mixing and reaction method of liquid A, liquid B, and liquid C described in Japanese Patent Application Laid-Open No. 2009-112892 were used. Figure 4 The apparatus described in , wherein a stirring tank with a uniform inner diameter was used, the inner diameter of the stirring tank was 420 mm, the gap between the outer end of the stirring tool and the inner circumference of the stirring tank was 1 mm, and the rotation speed of the stirring blade was the same as the rotation speed of the processing unit 10 of the fluid treatment device used in Example 8 (1130 rpm). In addition, liquid A was introduced into the stirring tank, liquid B was added to the thin film formed by liquid A pressed on the inner circumference of the stirring tank, and mixed and reacted, and liquid C was added to the thin film formed by the mixed liquid of liquid A and liquid B pressed on the inner circumference of the stirring tank, and mixed and reacted. Table 6 shows the operating conditions of the apparatus.

[0145] Washing of the silicon oxide-coated PR254 fine particles, measurement of the primary particle size and calculation of the particle size (D) of the silicon oxide-coated PR254 fine particles, measurement of the diffuse reflectance of the silicon oxide-coated PR254 fine particles and calculation of the area ratio of the diffuse reflectance in the target wavelength range (DiR [%), preparation of an organic pigment fine particle dispersion, preparation of a coating film, and measurement and evaluation of the brightness of the colored glass substrate were performed in the same manner as in Examples 1 to 6 or 7. The results are shown in Tables 5 and 6.

[0146] [Table 5]

[0147]

[0148] [Table 6]

[0149]

[0150] The silicon oxide-coated PR254 fine particles prepared in Example F-2 were subjected to FT-IR measurement, XRD measurement, and STEM observation in the same manner as in Examples 8 to 10. As a result, the FTIR measurement confirmed that the silicon oxide-coated PR254 fine particles had a peak at 1100 cm -1 There are peaks attributed to silicon oxide nearby, but no peaks attributable to silicon oxide were confirmed in XRD analysis. Furthermore, STEM observations revealed no crystalline lattice attributable to silicon oxide. These results confirm that the silicon oxide in the silicon oxide-coated PR254 particles is amorphous.

[0151] Elemental mapping and quantification using STEM (scanning transmission electron microscopy) were performed on the silicon oxide-coated PR254 microparticles prepared in Example F-2 using the same methods as in Examples 8 to 10. The results showed that, for a single particle observed in a dark field image (HADDF image), the distribution of silicon (Si) and oxygen (O) elements within a portion of the particle was observed. Furthermore, nitrogen (N) derived from PR254 was observed to be distributed within a narrower range than the distribution of silicon (Si) and oxygen (O). Therefore, it is believed that the silicon oxide-coated PR254 microparticles obtained in Example F-2 were partially covered with silicon oxide.

[0152] As in Examples 1 to 7, the ratio of the area of ​​diffuse reflectance at a wavelength of 620 to 750 nm to the total area of ​​diffuse reflectance in the entire measurement wavelength range (area ratio of diffuse reflectance in the target wavelength range: DiR [%]) and the brightness of the colored glass substrate are shown in Tables 5 and 6. The brightness of Examples 1 to 10, F-1, and F-2 relative to DiR is shown in Tables 5 and 6. Figure 2 In Examples 1 to 10, as shown in Tables 2, 4-6 and Figure 2 As can be seen, the higher the ratio of the diffuse reflectance area at the wavelength of 620-750 nm, which is important for the red filter, to the total diffuse reflectance area of ​​the entire measurement wavelength range (area ratio of the diffuse reflectance in the target wavelength range: DiR [%]), the higher the brightness of the color filter. The higher the ratio of the diffuse reflectance area at the wavelength of 620-750 nm, which is important for the red filter, to the total diffuse reflectance area of ​​the entire measurement wavelength range, the higher the brightness of the color filter can be controlled. Furthermore, it can be seen that the PR254 particles produced in Examples 8-10 and F-2, whose surfaces are at least partially covered with silicon oxide, can achieve higher DiR and color filter brightness control than the PR254 particles produced in Examples 1-6 and F-1, which are not covered with silicon oxide.

[0153] (Examples 11 to 13, Example 14)

[0154] Copper phthalocyanine (hereinafter referred to as CuPc) was used as the organic pigment. For Examples 11 to 13, the formulations of Liquids A to C were set as shown in Table 7, and the operating conditions of the fluid processing device were set as shown in Table 8. The same procedures as for Examples 8 to 10 were followed to obtain wet cake samples and dry powders of CuPc microparticles coated with silicon oxide. Furthermore, for Example 14, the formulations of Liquids A and B were set as shown in Table 9, the operating conditions of the fluid processing device were set as shown in Table 10, and the processing unit 10 was operated at a rotational speed of 1130 rpm. The same procedures as for Examples 1 to 6 were followed to obtain wet cake samples and dry powders of CuPc microparticles.

[0155] For the chemical substances listed in Tables 7 and 9 (including those represented by chemical formulas or abbreviations), acetic acid (purity >99.7%, manufactured by Kanto Chemical) was used as acetic acid, tetraethyl orthosilicate (manufactured by Wako Pure Chemical Industries, Ltd.) was used as TEOS, 3-aminopropyldiethoxymethylsilane (purity >97.0%, manufactured by Tokyo Chemical Industry Co., Ltd.) was used as 3-aminopropyldiethoxymethylsilane, PV FAST BLUE BG (manufactured by Clariant) was used as CuPc, 97% concentrated sulfuric acid (manufactured by Kishida Chemical) was used as 97% H2SO4, and ammonia (manufactured by Kishida Chemical) was used as 28% ammonia water. Pure water having a pH of 5.89 (29.3°C) and an electrical conductivity of 0.79 μS / cm was used as pure water.

[0156] Washing of the organic pigment particles (CuPc particles or silicon oxide-coated CuPc particles), measurement of the primary particle size of the organic pigment particles and calculation of the particle size (D), and measurement of the diffuse reflectance of the organic pigment particles were performed in the same manner as in Examples 1 to 6. The results are shown in Tables 8 and 10.

[0157] [Table 7]

[0158]

[0159] [Table 8]

[0160]

[0161] [Table 9]

[0162]

[0163] [Table 10]

[0164]

[0165] The CuPc fine particles covered with silicon oxide produced in Examples 11 to 13 were subjected to FT-IR measurement, XRD measurement, and STEM observation in the same manner as in Examples 8 to 10. As a result, in the FT-IR measurement, the CuPc fine particles covered with silicon oxide at 1100 cm -1 A peak from silicon oxide was confirmed near the surface, but no peak from silicon oxide was confirmed in XRD measurement. In addition, STEM observation confirmed that there was no lattice from silicon oxide. From the above results, it was confirmed that the silicon oxide of the CuPc particles covered with silicon oxide was amorphous.

[0166] Furthermore, elemental mapping and quantification using STEM (scanning transmission electron microscopy) were performed on the silicon oxide-coated CuPc microparticles prepared in Examples 11 to 13 using the same methods as in Examples 8 to 10. The results showed that, for a single particle observed in a dark field image (HADDF image), the distribution of silicon (Si) and oxygen (O) throughout the particle was observed, and copper (Cu) derived from copper phthalocyanine was observed to be distributed in a narrower range than the distribution of silicon (Si) and oxygen (O). Therefore, it is believed that the silicon oxide-coated CuPc microparticles obtained in Examples 11 to 13 were in a state where the entire surface of the CuPc microparticles was covered with silicon oxide.

[0167] (Example 15)

[0168] As Example 15, the CuPc raw material (PV FAST BLUE BG (manufactured by Clariant)) used in the production of CuPc microparticles or silicon oxide-coated CuPc microparticles in Examples 11 to 14 was pulverized using a bead mill to the same particle size as in Examples 11 to 14 to produce CuPc microparticles. The primary particle size of the resulting CuPc microparticles, the calculation of the particle size (D), and the measurement of the diffuse reflectance of the resulting CuPc microparticles were performed using the same methods as in Example 7. The results are shown in Tables 8 and 10.

[0169] In order to measure the brightness as a color filter, organic pigment fine particle dispersions and cured films (coating films) were prepared using the CuPc fine particles or the silicon oxide-coated CuPc fine particles obtained in Examples 11 to 15. Specifically, 24.32 parts by weight of the dry powder of the CuPc particles or CuPc particles covered with silicon oxide obtained in Examples 11 to 15, 28.80 parts by weight of the resin-type dispersant "BYK-LNP-21116" (solid content concentration of 40.0% by weight, manufactured by Bick Chemie Co., Ltd.), 25.60 parts by weight of the vinyl ester resin "Libokishi SPC-2000" (solid content concentration of 35% by weight, manufactured by Showa Denko) as a resin-type dispersant, and 80.00 parts by weight of propylene glycol monomethyl ether acetate (hereinafter also referred to as "PGMEA") as a dispersion medium were dispersed for 1 hour using a Clear Mix double-action stirrer (CLM-2.2 / 3.7W, manufactured by M Technology Co., Ltd.) at a rotor rotation number of 20,000 rpm and a screen rotation number of 18,000 rpm to obtain an organic pigment particle dispersion. To 60 parts by weight of the obtained organic pigment fine particle dispersion, 10 parts by weight of a photosensitive monomer (trade name: A-DPH, manufactured by Shin-Nakamura Chemical), 1.5 parts by weight of a photopolymerization initiator (4,4'-bis(dimethylamino)benzophenone, manufactured by Wako Pure Chemical Industries, Ltd.), 32 parts by weight of a resin-type dispersant (Lipokishi SPC-2000), 45 parts by weight of PGMEA, and 30 parts by weight of propylene glycol monomethyl ether (PGME) were added to prepare a spin coating liquid as a resist composition.

[0170] Each of the obtained spin coating solutions was applied to a 1 mm thick, 100 mm square glass substrate using a spin coater "Spin Coater MS-150A" (manufactured by Mikasa) until the film thickness reached a desired chromaticity (y = 0.120). The film was then dried (prebaked) at 90°C for 2 minutes and 30 seconds in a dryer, then heated and dried (postbaked) at 230°C for 30 minutes in a dryer, and cooled to obtain the colored glass substrates (color filters) of Examples 11 to 15. The brightness of the colored glass substrates was measured using the same method as in Examples 1 to 7.

[0171] Figure 3 , which are diffuse reflectance spectra at wavelengths of 380 nm to 780 nm, were measured using CuPc fine particles coated with silicon oxide produced under the conditions of Example 11 and powders of CuPc fine particles produced under the conditions of Example 14. Figure 3The measurement results shown are shown in Tables 8 and 10, and the ratio of the area of ​​the diffuse reflectance at a wavelength of 450 to 495 nm to the total area of ​​the diffuse reflectance in the entire measurement wavelength range (area ratio of the diffuse reflectance in the target wavelength range: DiR [%]) is calculated and shown together with the brightness of the colored glass substrate. In addition, the CuPc particles or CuPc particles covered with silicon oxide obtained in Examples 12 to 13 and 15 were also measured and calculated in the same manner, and the results are shown in Tables 8 and 10. The brightness of Examples 11 to 14 in Tables 8 and 10 is expressed as a relative value when the brightness of the colored glass plate of Example 15 is used as a reference (100). The brightness of Examples 11 to 15 relative to DiR is shown in Tables 8 and 10. Figure 4 .

[0172] From Tables 8, 10 and Figure 4 As can be seen, the higher the ratio of the diffuse reflectance area at wavelengths of 450-495 nm, which is important for the blue filter, to the total diffuse reflectance area of ​​the entire measurement wavelength range (area ratio of diffuse reflectance in the target wavelength range: DiR [%]), the higher the brightness of the color filter. Controlling the ratio of the diffuse reflectance area at wavelengths of 450-495 nm, which is important for the blue filter, to the total diffuse reflectance area of ​​the entire measurement wavelength range increases the brightness of the color filter. Furthermore, it can be seen that the CuPc particles produced in Examples 11-13, at least partially covered with silicon oxide, can achieve higher DiR and color filter brightness than the CuPc particles produced in Example 14, which are not covered with silicon oxide. When CuPc is used as the raw material for the organic pigment particles, CuPc particles or CuPc particles at least partially covered with silicon oxide can be produced using the apparatus described in Japanese Patent Application Laid-Open No. 2009-112892, similarly to Examples 8-10. In this case, the CuPc fine particles whose surfaces are at least partially covered with silicon oxide can control DiR and luminance to be higher than those of the CuPc fine particles whose surfaces are not covered with silicon oxide.

[0173] (Examples 16 to 18, Example 19)

[0174] As an organic pigment, zinc phthalocyanine chloride bromide (CI Pigment Green 58, PG58) was used. For Examples 16 to 18, the same procedures as for Examples 8 to 10 were followed, except that the formulations for Liquids A to C were set as shown in Table 11 and the operating conditions for the fluid treatment apparatus were set as shown in Table 12. A wet cake sample and a dry powder of PG58 fine particles coated with silicon oxide were obtained. Furthermore, for Example 19, the same procedures as for Examples 1 to 6 were followed, except that the formulations for Liquids A and B were set as shown in Table 13, the operating conditions for the fluid treatment apparatus were set as shown in Table 14, and the processing unit 10 was operated at a rotational speed of 1130 rpm. A wet cake sample and a dry powder of PG58 fine particles were obtained.

[0175] For the chemical substances listed in Tables 11 and 13 (including those represented by chemical formulas or abbreviations), acetic acid (purity >99.7%, manufactured by Kanto Chemical) was used as acetic acid, tetraethyl orthosilicate (manufactured by Wako Pure Chemical Industries, Ltd.) was used as TEOS, 3-aminopropyldiethoxymethylsilane (purity >97.0%, manufactured by Tokyo Chemical Industry Co., Ltd.) was used as 3-aminopropyldiethoxymethylsilane, 97% concentrated sulfuric acid (manufactured by Kishida Chemical) was used as 97% H2SO4, 30% fuming sulfuric acid (manufactured by Kanto Chemical) was used as 30wt% SO3 fuming sulfuric acid, chlorosulfuric acid (manufactured by Kanto Chemical) was used as chlorosulfuric acid, and ammonia (manufactured by Kishida Chemical) was used as 28% ammonia water. Pure water having a pH of 5.89 (29.3°C) and an electrical conductivity of 0.79 μS / cm was used as pure water.

[0176] Washing of the organic pigment particles (PG58 particles or PG58 particles coated with silicon oxide), measurement of the primary particle size of the organic pigment particles and calculation of the particle size (D), and measurement of the diffuse reflectance of the organic pigment particles were performed in the same manner as in Examples 1 to 6. The results are shown in Tables 12 and 14.

[0177] [Table 11]

[0178]

[0179] [Table 12]

[0180]

[0181] [Table 13]

[0182]

[0183] [Table 14]

[0184]

[0185] The PG58 fine particles covered with silicon oxide prepared in Examples 16 to 18 were subjected to FT-IR measurement, XRD measurement, and STEM observation in the same manner as in Examples 8 to 10. As a result, in the FT-IR measurement, the XRD measurement at 1100 cm -1 A peak derived from silicon oxide was confirmed nearby, but no peak derived from silicon oxide was confirmed in XRD analysis. Furthermore, STEM observation confirmed the absence of a crystalline lattice derived from silicon oxide. These results confirm that the silicon oxide in the silicon oxide-coated PG58 particles is amorphous.

[0186] The silicon oxide-coated PG58 microparticles prepared in Examples 16 to 18 were subjected to elemental mapping and quantification using STEM (scanning transmission electron microscopy) using the same methods as in Examples 8 to 10. The results showed that the distribution of silicon (Si) and oxygen (O) throughout the entire particle was observed in a dark field image (HADDF image) of a single particle. Zinc (Zn) derived from zinc chlorophthalocyanine bromide was observed to be distributed in a narrower range than the distribution of silicon (Si) and oxygen (O). Therefore, it is believed that the silicon oxide-coated PG58 microparticles obtained in Examples 16 to 18 were entirely covered with silicon oxide.

[0187] (Example 20)

[0188] As Example 20, the PG58 raw material used in producing PG58 microparticles or silicon oxide-coated PG58 microparticles in Examples 16 to 19 was pulverized using a bead mill to the same particle size as in Examples 16 to 19 to produce PG58 microparticles. The primary particle size and particle diameter (D) of the resulting PG58 microparticles were measured, and the diffuse reflectance of the resulting PG58 microparticles was measured using the same methods as in Example 7. The results are shown in Tables 12 and 14.

[0189] In order to measure the brightness as a color filter, organic pigment fine particle dispersions and cured films (coating films) were prepared using the PG58 fine particles or the silicon oxide-coated PG58 fine particles obtained in Examples 16 to 20. Specifically, 30.40 parts by weight of the dry powder of PG58 fine particles or PG58 fine particles covered with silicon oxide obtained in Examples 16 to 20, 21.02 parts by weight of a resin-type dispersant "BYK-LNP-6919" ​​(solid content concentration 60.9% by weight, manufactured by Bick Chemie Co., Ltd.), 27.43 parts by weight of a vinyl ester resin "Libokishi SPC-2000" (solid content concentration 35% by weight, manufactured by Showa Denko) as a resin-type dispersant, and 79.55 parts by weight of propylene glycol monomethyl ether acetate (hereinafter also referred to as "PGMEA") as a dispersion medium were dispersed using a Clear Mix double-action stirrer (CLM-2.2 / 3.7W, manufactured by M Technology Co., Ltd.) at a rotor speed of 20,000 rpm and a screen speed of 18,000 rpm for 1 hour to obtain an organic pigment fine particle dispersion. To 60 parts by weight of the obtained organic pigment fine particle dispersion were added 10 parts by weight of a photosensitive monomer "A-DPH" (manufactured by Shin-Nakamura Chemical), 1.5 parts by weight of a photopolymerization initiator (4,4'-bis(dimethylamino)benzophenone, manufactured by Wako Pure Chemical Industries, Ltd.), 32 parts by weight of a resin-type dispersant (Lipokishi SPC-2000), 45 parts by weight of PGMEA, and 30 parts by weight of propylene glycol monomethyl ether (PGME) to prepare a spin coating liquid as a resist composition.

[0190] Each of the obtained spin coating solutions was applied to a 1 mm thick, 100 mm square glass plate using a spin coater "Spin Coater MS-150A" (manufactured by Mikasa) until the film thickness reached a desired chromaticity (y = 0.500). The solution was then dried (prebaked) at 90°C for 2 minutes and 30 seconds in a dryer, then heated and dried (postbaked) at 230°C for 30 minutes in a dryer, and cooled to obtain the colored glass plates (color filters) of Examples 16 to 20. The brightness of the colored glass substrates was measured using the same method as in Examples 1 to 7.

[0191] Figure 5 , the diffuse reflectance spectra at wavelengths of 380 nm to 780 nm measured using the powder of PG58 fine particles covered with silicon oxide produced under the conditions of Example 17 and the powder of PG58 fine particles produced under the conditions of Example 20 are shown. Figure 5The measurement results shown in , the ratio of the area of ​​the diffuse reflectance at a wavelength of 495 to 570 nm to the total area of ​​the diffuse reflectance of the entire measurement wavelength range (area ratio of the diffuse reflectance in the target wavelength range: DiR [%]) was calculated and shown in Tables 12 and 14 together with the brightness of the colored glass substrate. In addition, the PG58 particles or PG58 particles covered with silicon oxide obtained in Examples 16, 18 to 19 were also measured in the same manner, and the results are shown in Tables 10 and 12. The brightness of Examples 16 to 19 in Tables 12 and 14 is expressed as a relative value when the brightness of the colored glass plate of Example 20 is used as a reference (100). The brightness of Examples 16 to 20 relative to DiR is shown in Tables 10 and 12. Figure 6 .

[0192] From Tables 12, 14 and Figure 6 As can be seen, the higher the ratio of the diffuse reflectance area at wavelengths of 495-570 nm, which is important for the green filter, to the total diffuse reflectance area of ​​the entire measurement wavelength range (area ratio of diffuse reflectance in the target wavelength range: DiR [%]), the higher the brightness of the color filter. The higher the ratio of the diffuse reflectance area at wavelengths of 495-570 nm, which is important for the green filter, to the total diffuse reflectance area of ​​the entire measurement wavelength range, the higher the brightness of the color filter can be controlled. Furthermore, it can be seen that the PG58 particles produced in Examples 16-18, at least partially covered with silicon oxide, can achieve higher DiR and color filter brightness than the PG58 particles produced in Example 19, which are not covered with silicon oxide. When PG58 is used as the raw material for the organic pigment particles, the apparatus described in Japanese Patent Application Laid-Open No. 2009-112892 can also be used to produce PG58 particles or PG58 particles at least partially covered with silicon oxide, as in Examples 8-10. In this case, the PG58 particles whose surfaces are at least partially covered with silicon oxide can control DiR and brightness to be higher than those of the PG58 particles whose surfaces are not covered with silicon oxide.

Claims

1. A method for evaluating the brightness of a coating film produced using an organic pigment fine particle dispersion, characterized in that: The process includes the following steps: Step (I): a step of obtaining at least one organic pigment fine particles at least a portion of which is covered with an oxide. Step (II): a step of measuring the diffuse reflectance of the powder of the organic pigment fine particles in the wavelength range of 380 to 780 nm, Step (III): dispersing the organic pigment particles in a solvent to obtain an organic pigment particle dispersion. Step (IV): measuring the brightness of a coating film produced using the organic pigment fine particle dispersion, and determining the relationship between the brightness of the coating film and the ratio of the area of ​​diffuse reflectance in the target wavelength range to the total area of ​​diffuse reflectance in the entire measurement wavelength range; The brightness of the coating film obtained in step (IV) is evaluated without actually forming a coating film on the organic pigment particles to be evaluated, using the relationship between the brightness of the coating film and the ratio of the area of ​​the diffuse reflectance in the target wavelength range to the total area of ​​the diffuse reflectance in the entire measurement wavelength range.

2. The evaluation method according to claim 1, wherein The primary particle size of the organic pigment fine particles is 100 nm or less.

3. The evaluation method according to claim 1, wherein The above-mentioned oxides include amorphous oxides.

4. The evaluation method according to claim 1 or 3, wherein The above oxide is silicon oxide.

5. The evaluation method according to claim 1 or 2, characterized in that In the diffuse reflectance spectrum of the organic pigment particles in the wavelength range of 380 to 780 nm, The organic pigment particles are red pigment particles, the target wavelength range is 620 to 750 nm, and the ratio of the diffuse reflectance area in the target wavelength range to the total diffuse reflectance area in the entire measurement wavelength range is 71% or more.

6. The evaluation method according to claim 1 or 2, characterized in that In the diffuse reflectance spectrum of the organic pigment particles in the wavelength range of 380 to 780 nm, The organic pigment particles are blue pigment particles, the target wavelength range is 450 to 495 nm, and the ratio of the diffuse reflectance area in the target wavelength range to the total diffuse reflectance area in the entire measurement wavelength range is 30% or more.

7. The evaluation method according to claim 1 or 2, characterized in that In the diffuse reflectance spectrum of the organic pigment particles in the wavelength range of 380 to 780 nm, The organic pigment particles are green pigment particles, the target wavelength range is 495 to 570 nm, and the ratio of the diffuse reflectance area in the target wavelength range to the total diffuse reflectance area in the entire measurement wavelength range is 51% or more.

8. The evaluation method according to claim 1 or 2, characterized in that The organic pigment particles are obtained by mixing an organic pigment solution obtained by dissolving an organic pigment in a good solvent with a poor solvent for precipitating the organic pigment particles from the organic pigment solution, precipitating the organic pigment particles to obtain organic pigment particles, and covering at least a portion of the surface of the obtained organic pigment particles with an oxide.

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