Pigment dispersions and coating film-forming compositions

Abstract

To provide a pigment dispersion having improved coloring power, and a composition for forming a coating film which contains each component of the pigment dispersion.SOLUTION: A pigment dispersion contains a red organic pigment R, a yellow organic pigment Y, a resin type dispersant, a dispersion resin, and a solvent, wherein the red organic pigment R is a color index pigment red 63:1, a weight ratio R / Y of the red organic pigment R to the yellow organic pigment Y is 69 / 31 to 26 / 74, the resin type dispersant is a block copolymer having a quaternary ammonium base and a tertiary amino group, and the dispersion resin is an alkali-soluble resin having an acid value.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a pigment dispersion and a composition for forming a coating film, and particularly to a pigment dispersion and a composition for forming a coating film containing Color Index Pigment Red 63:1 as a red organic pigment.

Background Art

[0002] For example, a color filter used in a solid-state imaging device, a display device, or the like is produced by forming a fine pattern using a composition for forming a coating film containing a pigment or the like. In recent years, further improvement in image quality and high definition of solid-state imaging devices, display devices, and the like has been demanded. The color filter is required to have various color characteristics and color separation performance. However, as the pixel size becomes smaller due to higher image quality and higher definition, there is a concern that it becomes difficult to manufacture a color filter that satisfies such requirements. For example, as the pixel size becomes smaller, there is a concern that residues may occur when producing a pixel pattern, and problems such as color fading and failure to meet the requirements for color characteristics and color separation performance may occur.

[0003] As a measure for improving the residues generated when producing this pixel pattern, Patent Document 1 proposes a coloring composition for a color filter containing a colorant containing an isoindoline-based pigment, a specific binder resin, and the like. By using this coloring composition, it is said that a coloring composition for a color filter that does not fade even when immersed in an alkaline developer can be provided, and a color filter with few residues and good developability can be provided.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, while various red pigments are known for use in color filters, Color Index (hereinafter abbreviated as "CI") Pigment Red (hereinafter abbreviated as "PR") 177, known for its high coloring power, is sometimes selected. In particular, from the viewpoint of improving the color characteristics and color separation performance of color filters, such as from the perspective of improving image quality and resolution, CIPR177 is sometimes used as a red pigment. Patent Document 1 also describes the use of CIPR177 as a red organic pigment used in combination with isoindoline pigments, from the viewpoint of obtaining high coloring power. Therefore, according to the color filter coloring composition described in Patent Document 1, when isoindoline pigments and CIPR177 are used as colorants, it is thought that color fading is suppressed to some extent when immersed in an alkaline developer, and a color filter with reasonably high image quality and resolution can be obtained. However, there is room for improvement to meet the recent demands for higher image quality and resolution.

[0006] Therefore, the object of the present invention is to provide a pigment dispersion with improved coloring power and a coating film-forming composition containing each component of the pigment dispersion. [Means for solving the problem]

[0007] The inventors diligently conducted research to solve the aforementioned problems. As a result, they found that the aforementioned problems could be solved by adopting CIPR63:1 as the red organic pigment R used in combination with the yellow organic pigment Y, setting their weight ratio R / Y within a predetermined range, and using these organic pigments R and Y in combination with a specific resin-type dispersant and dispersion resin. The gist of the present invention is as follows.

[0008] The first aspect of the present invention relates to a pigment dispersion comprising a red organic pigment R, a yellow organic pigment Y, a resin-type dispersant, a dispersion resin, and a solvent, wherein the red organic pigment R has a color index pigment red of 63:1, the weight ratio R / Y of the red organic pigment R to the yellow organic pigment Y is 69 / 31 to 26 / 74, the resin-type dispersant is a block copolymer having a quaternary ammonium base and a tertiary amino group, and the dispersion resin is an alkali-soluble resin having an acid value.

[0009] The aforementioned yellow organic pigment Y may be color index pigment yellow 139.

[0010] The second aspect of the present invention relates to a film-forming composition comprising the red organic pigment R, the yellow organic pigment Y, the resin-type dispersant, the dispersion resin, and the solvent contained in the pigment dispersion, and a film-forming component. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a pigment dispersion with improved coloring power and a coating film-forming composition containing each component of the pigment dispersion. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described below.

[0013] (Pigment dispersion) The pigment dispersion according to the embodiment of the present invention comprises a red organic pigment R (hereinafter sometimes referred to as "pigment R"), a yellow organic pigment Y (hereinafter sometimes referred to as "pigment Y"), a resin-type dispersant, a dispersion resin, and a solvent. Pigment R has a CIPR ratio of 63:1. The weight ratio R / Y of pigment R to pigment Y is 69 / 31 to 26 / 74. The resin-type dispersant is a block copolymer having a quaternary ammonium base and a tertiary amino group. The dispersion resin is an alkali-soluble resin having an acid value.

[0014] The red organic pigment R is CIPR63:1. Although CIPR63:1 has not been previously considered for color filter applications, it has been found to possess good coloring power when dispersed under specific conditions and cured into a film. CIPR63:1 is a monoazo pigment with CAS No. 6417-83-0. Commercially available CIPR63:1 can be used.

[0015] The yellow organic pigment Y is not particularly limited, and any pigment used, for example, in color filter applications, can be selected. Such a yellow organic pigment Y is designated by its CI number as Pigment Yellow (PY). 1, 1:1, 2, 3, 4, 5, 6, 9, 10, 12, 13, 14, 16, 17, 20, 24, 31, 32, 34, 35, 35:1, 36, 36:1, 37, 37:1, 40, 41, 42, 43, 48, 53, 55, 61, 62, 62:1, 63, 65, 73, 74, 75, 81, 83, 86, 87, 93, 94, 95, 97, 100, 101, 104, 105, 108, 109, 110, 111, 116, 117, 119, 120, 125, 126, 127, 127:1, 128, 129, 133, 134, 136, 13 Examples include 7, 138, 139, 142, 147, 148, 150, 151, 153, 154, 155, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 172, 173, 174, 175, 176, 180, 181, 182, 183, 184, 185, 188, 189, 190, 191, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 202, 203, 204, 205, 206, 207, 208, etc. Of these, CIPY83, 117, 129, 138, 139, 150, 154, 155, 180, and 185 are preferred from the viewpoint of high brightness and wide color gamut, 83, 138, 139, 180, and 185 are more preferred, and 139 is particularly preferred.

[0016] In addition to the aforementioned pigments R and Y, other pigments of other colors may be included as needed.

[0017] The average primary particle size of each pigment contained in the pigment dispersion can be appropriately adjusted within a range that does not affect contrast, etc. A preferred average primary particle size is 10 to 100 nm, more preferably 10 to 50 nm, and particularly preferred 10 to 30 nm. The primary particle size can be measured, for example, from an image of the pigment taken with a transmission electron microscope at a magnification of 100,000x. Alternatively, the average primary particle size can be determined by measuring 100 particles and taking the average value.

[0018] Depending on the type of pigment, pre-milling may be performed to adjust the average primary particle size, etc. Milling can be carried out according to standard methods depending on the type of pigment, etc. Examples of such milling methods include solvent-salt milling.

[0019] The weight ratio R / Y of pigment R to pigment Y, based on solid content, should be 69 / 31 to 26 / 74, but 64 / 36 to 36 / 64 is preferred. The total content of pigment R and pigment Y (as solid content) in the pigment dispersion should preferably be 3 to 20% by weight. If pigments other than pigment R and pigment Y are included, the total content of pigment R and pigment Y in the total pigments should preferably be 60 to 100% by weight.

[0020] The resin-type dispersant is a block copolymer having a quaternary ammonium base and a tertiary amino group. The main chain structure of the block copolymer is not particularly limited, but a main chain structure formed by the addition polymerization of vinyl monomers is preferred. Among these, acrylic block copolymers having a quaternary ammonium base and a tertiary amino group are preferred. An example of an acrylic block copolymer having a quaternary ammonium base and a tertiary amino group is BYK-LPN21116 manufactured by Bic Chemie.

[0021] The amine value of the resin-type dispersant is preferably 50 to 100 mgKOH / g. The acid value is preferably 0 to 50 mgKOH / g, more preferably 0 mgKOH / g. The amine value (amine value in terms of solid content) can be determined by, for example, a method in accordance with DIN 16945. The acid value (acid value in terms of solid content) can be determined by, for example, a method in accordance with DIN EN ISO 2114.

[0022] The molecular weight of the resin-type dispersant is not particularly limited, but the weight average molecular weight is preferably 3000 to 100000, more preferably 5000 to 20000.

[0023] The content of the resin-type dispersant is not particularly limited, but from the viewpoints of improving dispersion stability and viscosity, it is preferably 10 to 60% by weight based on solid content with respect to the total amount of pigments contained in the pigment dispersion. In this case, the total amount of pigments includes the pigment derivative when it is included.

[0024] The dispersion resin is used to improve the dispersibility of the pigment in the pigment dispersion and to improve the dispersibility of the particles in the coating film-forming composition when a coating film-forming composition is formed using the pigment dispersion. The dispersion resin is an alkali-soluble resin having an acid value, and is not particularly limited as long as it can ensure the dispersibility and viscosity stability of pigments and the like in combination with the above-mentioned predetermined resin-type dispersant, but the acid value is 50 to 200 mgKOH / g or less, and it is preferably a resin having no amine value. The acid value (acid value in terms of solid content) can be determined by, for example, a method in accordance with DIN EN ISO 2114. "Having no amine value" means that the value obtained by determining the amine value (amine value in terms of solid content) by, for example, a method in accordance with DIN 16945 is 0 mgKOH / g.

[0025] The dispersion resin tends to contribute to good dispersibility of the particles in the coating film-forming composition when the coating film-forming component used in the coating film-forming composition described below is a polymerizable component, particularly a photopolymerizable component. Needless to say, when the coating film-forming component is a polymer described below, it also contributes to good dispersibility as in the case of the polymerizable component. Examples of such a dispersion resin include an alkali-soluble resin having an acid value within a predetermined range and no amine value. Such an alkali-soluble resin can be appropriately selected from, for example, linear organic polymer polymers having at least one group that promotes alkali solubility (such as a carboxyl group, a phosphate group, a sulfonic acid group, etc.) in the molecule. Among these, preferably, it is soluble in an organic solvent and can be developed with a weak alkaline aqueous solution. Preferred examples of the alkali-soluble resin include acrylic resins.

[0026] From the viewpoint of the dispersion stability of the pigment when used in combination with a resin-type dispersant, the weight average molecular weight of the dispersion resin is preferably 3,000 to 100,000, and more preferably 5,000 to 20,000.

[0027] Commercially available dispersion resins can be used. For example, Foret (registered trademark) ZAH-110 manufactured by Soken Chemical & Engineering Co., Ltd. can be mentioned.

[0028] The concentration of the dispersion resin in the pigment dispersion is preferably 0.5 to 18% by weight based on the solid content. Also, based on the solid content, when 100 parts by weight of the pigment and other pigments are included, 10 to 60 parts by weight is preferably relative to the total 100 parts by weight of all pigments. When the pigment includes a pigment derivative, 100 parts by weight of the pigment includes this.

[0029] The solvent is not particularly limited, but examples include aromatic, ketone, ester, glycol ether, alcohol, and aliphatic solvents. From the viewpoint of film-forming properties, at least one selected from aromatic, ketone, ester, and glycol ether solvents is preferred, and at least one selected from glycol ether and ester solvents is more preferred. Examples of glycol ether solvents include propylene glycol monomethyl ether (PM). Examples of ester solvents include propylene glycol monomethyl ether acetate (PMA or PGMEA). One of these solvents may be used, or two or more may be used in combination. When two are combined, for example, it is preferable to use a glycol ether solvent and an ester solvent in combination, and for example, it is particularly preferable to use PM and PMA in combination.

[0030] In a pigment dispersion, the solvent content is not particularly limited. For example, it can be 60 to 90% by weight in the pigment dispersion.

[0031] The pigment dispersion may optionally contain pigment derivatives. Pigment derivatives are compounds that use an organic pigment as a basic skeleton and introduce acidic or aromatic groups as substituents to the side chains. Examples of acidic groups include sulfate groups, carboxyl groups, and phosphate groups. Specific examples of organic pigments that form the parent skeleton include quinacridone pigments, phthalocyanine pigments, azo pigments, quinophthalone pigments, isoindoline pigments, isoindolinone pigments, quinoline pigments, diketopyrrolopyrrole pigments, benzimidazolone pigments, and dioxazine pigments. In addition, the parent skeleton may also include pale yellow aromatic polycyclic compounds such as naphthalene, anthraquinone, triazine, and quinoline, which are not generally called dyes. One of these pigment derivatives may be used, or two or more may be used in combination. As for the pigment derivatives, those having a quinophthalone-based pigment as the parent skeleton are preferred, quinophthalone-based pigments with acidic groups introduced as substituents on the side chains are more preferred, and quinophthalone-based pigments with sulfate groups introduced on the side chains are even more preferred.

[0032] In a pigment dispersion, the content of the pigment derivative is not particularly limited. For example, it can be 2 to 18 parts by weight on a solids basis per 100 parts by weight of the total pigment. Furthermore, when considering the content of the pigment derivative for red organic pigment R and yellow organic pigment Y respectively, it can be 2 to 18 parts by weight on a solids basis per 100 parts by weight of red organic pigment R, and 2 to 18 parts by weight on a solids basis per 100 parts by weight of yellow organic pigment Y.

[0033] The pigment dispersion may contain other additives in addition to the components mentioned above. Examples of other additives include antioxidants, anti-flocculation agents, and surface modifiers (leveling agents).

[0034] The pigment dispersions described above can be obtained, for example, by adding the aforementioned pigments, resin-type dispersants, dispersion resins, and solvents (and other components as needed) to a known disperser such as a bead mill, sand mill, disperser, or paint conditioner, and dispersing them. Alternatively, the pigment dispersions can be obtained by similarly adding a resin-type dispersant, dispersion resin, and solvent (and other components as needed) to a disperser for each of the red organic pigment R and yellow organic pigment Y, dispersing them, mixing the dispersions of red organic pigment R and yellow organic pigment Y in a desired ratio, and then subjecting them to further dispersion or stirring treatments. Furthermore, when using a grinding medium for dispersion treatment, the size of the grinding medium may be changed as needed, and the dispersion treatment may be performed multiple times. In addition, if necessary, filtration may be performed after dispersion treatment, or a solvent may be added and stirring may be performed to adjust the pigment concentration.

[0035] (Composition for coating film formation) A coating film-forming composition according to an embodiment of the present invention includes each component contained in the aforementioned pigment dispersion and a coating film-forming component.

[0036] Examples of film-forming components include polymerizable components, polymers, and mixtures thereof.

[0037] Examples of polymers include thermoplastic urethane resins, (meth)acrylic resins, polyamide resins, polyimide resins, styrene-maleic acid resins, polyester resins, silicone resins, and cardo resins.

[0038] The polymer content in the coating film-forming composition is preferably 3 to 10% by weight, based on the solid content. The polymer content in the coating film-forming composition is the total amount of polymer and the dispersed resin contained in the pigment dispersion, based on the solid content. The molecular weight of the polymer can be determined as appropriate.

[0039] Among the polymers used as film-forming components as described above, alkali-soluble resins that are soluble in alkaline solutions are preferred. The inclusion of an alkali-soluble resin can, for example, improve pattern formation when the pigment composition is applied to the photolithography process during the manufacture of color filters. The aforementioned alkali-soluble resins can be used. Furthermore, the dispersion resin used for the pigment dispersion and the film-forming component may be the same or different. From the viewpoint of developability, the weight-average molecular weight of the polymer is preferably 3000 to 50000.

[0040] Various alkali-soluble resins are commercially available that can be used as coating film-forming components. Specific examples are listed below, but the list is not limited to these. Showa Denko Corporation: Lipoxy (registered trademark) SPC-2000 Mitsubishi Chemical Corporation: Diana-L (registered trademark) HR series, Daicel Corporation: Cyclomer (registered trademark) P series, Daicel Ornex Co., Ltd.: Ebecryl (registered trademark) 3700, Soken Chemical Co., Ltd.: Follett (registered trademark) ZAH-110, etc.

[0041] As for polymerizable components, photopolymerizable components are preferred because they can be easily patterned by developing (negative development).

[0042] The usable photopolymerizable components include photopolymerizable compounds and photopolymerization initiators. Such photopolymerizable compounds and photopolymerization initiators can be those described in, for example, Japanese Patent Application Publication No. 2009-179789. More specifically, such photopolymerizable compounds are addition polymerizable compounds having at least one ethylenically unsaturated double bond, and are selected from compounds having at least one, preferably two or more, terminal ethylenically unsaturated bonds. Such a group of compounds is widely known in the art and can be used without particular limitation. Photopolymerizable compounds can have chemical forms such as monomers, prepolymers, i.e., dimers, trimers and oligomers, or mixtures thereof, and copolymers thereof.

[0043] Examples of monomers and copolymers thereof include unsaturated carboxylic acids (e.g., acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), their esters, and amides. Preferably, esters of unsaturated carboxylic acids and aliphatic polyhydric alcohol compounds, and amides of unsaturated carboxylic acids and aliphatic polyhydric amine compounds are used. Addition reaction products of unsaturated carboxylic acid esters or amides having nucleophilic substituents such as hydroxyl groups, amino groups, and mercapto groups with monofunctional or polyfunctional isocyanates or epoxys, and dehydration condensation reaction products with monofunctional or polyfunctional carboxylic acids are also suitably used. Addition reaction products of unsaturated carboxylic acid esters or amides having electrophilic substituents such as isocyanate groups and epoxy groups with monofunctional or polyfunctional alcohols, amines, and thiols, and substitution reaction products of unsaturated carboxylic acid esters or amides having leaving substituents such as halogen groups and tosyloxy groups with monofunctional or polyfunctional alcohols, amines, and thiols are also suitable. As another example, it is also possible to use a group of compounds in which the unsaturated carboxylic acids mentioned above are replaced with unsaturated phosphonic acids, styrene, vinyl ethers, etc.

[0044] The photopolymerizable compound is preferably present in the coating film-forming composition at a concentration of 0.1 to 20% by weight, more preferably 1 to 10% by weight, based on the solid content. These compounds may be used individually or in combination of two or more. Furthermore, the appropriate structure, formulation, and amount of the photopolymerizable compound can be arbitrarily selected from viewpoints such as the degree of polymerization inhibition by oxygen, resolution, coverage, refractive index change, and surface tackiness.

[0045] As the aforementioned photopolymerization initiator, one described in Japanese Patent Application Publication No. 2009-179789 can also be used. Examples include acetophenone-based, ketal-based, benzophenone-based, benzoin-based, benzoyl-based, xanthone-based, active halogen compounds (triazine-based, oxadiazole-based, coumarin-based), acridine-based, biimidazole-based, and oxime ester-based compounds. Specific examples of benzophenone-based photopolymerization initiators include, for example, benzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, and 4,4'-dichlorobenzophenone.

[0046] The preferred content of the photopolymerization initiator in the coating film-forming composition is 0.1 to 10% by weight, based on the solid content. When the photopolymerization initiator content is within this range, the polymerization reaction proceeds smoothly, and a film with good strength can be formed.

[0047] When the coating film-forming composition includes a photopolymerizable component as a coating film-forming component, the aforementioned alkali-soluble resin may be added separately in addition to that contained in the pigment dispersion.

[0048] Various additives such as sensitizers (sensitizing dyes), chain transfer agents, fluorine-based organic compounds, thermal polymerization initiators, thermal polymerization components, fillers, surfactants, adhesion promoters, antioxidants, anti-coagulation agents, and surface modifiers (leveling agents) may be added to the coating film-forming composition as needed.

[0049] A coating film-forming composition can be obtained, for example, by mixing and stirring the aforementioned components (e.g., the aforementioned pigment dispersion and coating film-forming component, or, if a pigment dispersion is not used, the aforementioned components contained therein and the coating film-forming component) in a predetermined proportion using, for example, a disperser or shaker. The resulting mixture may be filtered as needed, or a solvent may be added and stirred to adjust the solid content concentration.

[0050] Furthermore, when using a pigment dispersion, the content of each component in the film-forming composition can be adjusted by blending the pigment dispersion so that the pigment concentration in the film-forming composition is 8 to 60% by weight on a solids basis, and by blending the film-forming components so that the solids concentration in the film-forming composition is 15 to 60% by weight. Note that the pigment concentration includes pigment derivatives if they are used. Even when not using a pigment dispersion, the content of each component can be determined in accordance with the content of each component of the aforementioned pigment dispersion.

[0051] The above-described coating-forming composition can be cured by processing it according to standard methods such as heating or irradiation with ultraviolet light. This cured film has good coloring ability and is suitable as a constituent material for color filters used in solid-state image sensors, display devices, and the like. [Examples]

[0052] The embodiments of the present invention will be described in detail below based on the examples.

[0053] (Manufacturing example A) 20 parts by mass of CIPigment Yellow 138 (100% solids by weight) and 300 parts by mass of 98% concentrated sulfuric acid were placed in a 500 mL separable flask and reacted at 120°C for 5 hours to obtain a sulfonated phthalimidoquinophthalone compound. The reaction mixture was poured into 3000 parts by mass of water while stirring to precipitate the sulfonated phthalimidoquinophthalone compound, stirred for 30 minutes, and then filtered and washed with water three times. The resulting wet cake was washed with 300 parts by mass of 1% dilute sulfuric acid, filtered, and washed with water. It was dried in a hot air dryer to obtain 54 parts by mass of pigment derivative 1 represented by the following formula (1). The obtained pigment derivative 1 was subjected to mass spectrometry using a Hewlett-Packard liquid chromatography-mass spectrometer "LC / MS" (Electro Spray Ionization), and m / z = 773 [MH]- was detected.

[0054] [ka]

[0055] (Manufacturing Example 1) A mill base was obtained by blending 12.22 parts by weight of PR63:1 (100% solids by weight) as a red organic pigment R, 16.25 parts by weight of a resin-type dispersant (manufactured by Bic Chemie, BYK-LPN21116, a dispersant having a quaternary ammonium salt and a tertiary amino group, acid value: 0 mg KOH / g, amine value: 75 mg KOH / g, solids by weight 40%), 18.57 parts by weight of a dispersion resin (manufactured by Soken Chemical Co., Ltd., Follett® ZAH-110, acid value: 100 mg KOH / g, alkali-soluble, acrylic polymer, solids by weight: 35.0%), 10.78 parts by weight of the pigment derivative obtained in Production Example A, 5.0 parts by weight of propylene glycol monomethyl ether (PM), and 47.18 parts by weight of propylene glycol monomethyl ether acetate (PMA). Next, 400 parts by weight of zirconia beads with a diameter of 0.8 mm were mixed with 100 parts by weight of the mill base and dispersed with paint conditioner for 30 minutes. Then, 400 parts by weight of zirconia beads with a diameter of 0.05 mm were mixed with 100 parts by weight of the mill base and dispersed with paint conditioner for 30 minutes. After that, the zirconia beads were removed to obtain a red pigment dispersion.

[0056] (Manufacturing example 2) A mill base was prepared by blending 14.4 parts by weight of PY139 (100% solids by weight) as a yellow organic pigment, 9.38 parts by weight of a resin-type dispersant (manufactured by BIC Chemie, BYK-LPN21116), 10.71 parts by weight of a dispersion resin (manufactured by Soken Chemical Co., Ltd., Forret® ZAH-110), 10.6 parts by weight of the pigment derivative obtained in Production Example A, 5.0 parts by weight of PM, and 59.91 parts by weight of PMA. Next, 400 parts by weight of 0.8 mm diameter zirconia beads were added to 100 parts by weight of the mill base and dispersed with paint conditioner for 30 minutes. Subsequently, 400 parts by weight of 0.1 mm diameter zirconia beads were added to 100 parts by weight of the mill base and dispersed with paint conditioner for 30 minutes. After that, the zirconia beads were removed to obtain a yellow pigment dispersion.

[0057] (Manufacturing Example 3) A red pigment dispersion was obtained in the same manner as in Production Example 1, except that Color Index Pigment Red 177 (100% by weight solids) was used as the red organic pigment R.

[0058] (Example 1) The red pigment dispersion from Production Example 1 and the yellow pigment dispersion from Production Example 2 were mixed so that the weight ratio (R' / Y', based on solid content) of the total amount of PR63:1 and pigment derivative 1 (R') to the total amount of PY139 and pigment derivative 1 (Y') was 50 / 50, and the mixture was stirred with a disperser to obtain the pigment dispersion of Example 1. The weight ratio (R / Y, based on solid content) of PR63:1 (R) to PY139 (Y) was 49 / 51.

[0059] (Example 2) The pigment dispersion of Example 2 was obtained in the same manner as in Example 1, except that the weight ratio (R' / Y', based on solid content) of the total amount of PR63:1 and pigment derivative 1 (R') to the total amount of PY139 and pigment derivative 1 (Y') was set to 60 / 40. The weight ratio (R / Y, based on solid content) of PR63:1 (R) to PY139 (Y) was 59 / 41.

[0060] (Comparative Example 1) A pigment dispersion of Comparative Example 1 was obtained in the same manner as in Example 2, except that the red pigment dispersion of Production Example 3 was used instead of the red pigment dispersion of Production Example 1.

[0061] (evaluation) <Manufacturing of coating film-forming compositions> The pigment dispersions of Examples 1 and 2 and Comparative Example 1, an acrylic polymer (Follet® ZAH-110, manufactured by Soken Chemical Co., Ltd.) as a film-forming component, and a solvent (PMA) were mixed and stirred with a disperser to prepare the film-forming compositions of Examples 1 and 2 and Comparative Example 1, respectively. At this time, the components were blended so that the solid content of the film-forming composition was 20% by weight, and the concentration of the red organic pigment, yellow organic pigment, and pigment derivatives in the film-forming composition was 50% by weight based on the solid content.

[0062] <Manufacturing of hardened films> Using the pigment dispersions and coating film-forming compositions of Examples 1, 2, and Comparative Example 1, the rotation speed of the spin coater was adjusted so that the chromaticity was x=0.6830 and y=0.3130±0.0005, and each coating film was formed on the surface of a substrate (material: glass). The substrate (coated plate) on which each coating film was formed was dried at room temperature (23°C) for 3 minutes, then heated at 90°C for 2.5 minutes (pre-bake), and subsequently heated at 230°C for 30 minutes (post-bake) to produce cured films of the pigment dispersions and coating film-forming compositions of Examples 1, 2, and Comparative Example 1 on the substrate.

[0063] <Measuring film thickness> The film thickness of the pigment dispersions and cured films of the coating-forming compositions in Examples 1 and 2 and Comparative Example 1 was measured using a non-contact film thickness meter (FIKMETRICS, F-20EXR).

[0064] Table 1 shows the measurement results for chromaticity x(Rx), y(Ry), and film thickness after post-baking.

[0065] [Table 1]

[0066] As shown in Table 1, the cured film obtained using a pigment dispersion and coating film-forming composition containing PR63:1 as a red organic pigment and satisfying the predetermined conditions shows that the film thickness required to obtain the same chromaticity is smaller, i.e., the film has higher coloring power, compared to the case where PR177, which is conventionally known to have high coloring power and is commonly used in color filter applications, is used.

Claims

1. A pigment dispersion comprising a red organic pigment R, a yellow organic pigment Y, a resin-type dispersant, a dispersion resin, and a solvent, The aforementioned red organic pigment R is a color index pigment red 63:1, The aforementioned yellow organic pigment Y is color index pigment yellow 139. The weight ratio R / Y of the red organic pigment R to the yellow organic pigment Y is 69 / 31 to 26 / 74. The resin-type dispersant is a block copolymer having a quaternary ammonium base and a tertiary amino group. A pigment dispersion in which the dispersion resin is an alkali-soluble resin having an acid value.

2. A coating film-forming composition comprising a pigment dispersion according to claim 1 and a coating film-forming component.

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