pigment dispersion

Abstract

To provide a pigment dispersion for coloring a resin composition for photolithography.SOLUTION: A pigment dispersion according to the present invention is a pigment dispersion for coloring a resin composition for photolithography, containing a pigment, an organic solvent, and an acid.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a pigment dispersion for coloring a resin composition for photolithography. [Background technology]

[0002] Conventionally, organic electroluminescent (organic EL) elements included in organic electroluminescent displays, organic electroluminescent lighting, etc. have been manufactured by forming partition walls (banks) on a substrate and then laminating various functional layers within the area surrounded by the partition walls. As a method for easily forming such partition walls, a photolithography method using a resin composition for photolithography is known.

[0003] Patent Document 1 discloses a photosensitive colored resin composition containing (A) a photopolymerization initiator, (B) an alkali-soluble resin, (C) a photopolymerizable compound, (D) a colorant, and (E) a liquid-repellent agent, wherein the (A) photopolymerization initiator has an absorbance at a wavelength of 400 nm that is greater than or equal to the maximum absorption wavelength (λ ) between 300 and 400 nm. max ) is 20% or more of the absorbance at a wavelength of 400 nm, and the absorbance at a maximum absorption wavelength (λ max ) is 10% or less of the absorbance at 1000 kJ / cm 3 / 2 ...

[0004] Patent Document 2 discloses a negative-type photosensitive resin composition containing (A) an alkali-soluble resin, (B) a radical-polymerizable compound, (C) a photopolymerization initiator, and (Da) a black pigment, wherein the (A) alkali-soluble resin contains one or more compounds selected from (A1-1) a polyimide, (A1-2) a polyimide precursor, (A1-3) a polybenzoxazole, and (A1-4) a polybenzoxazole precursor, the (C) photopolymerization initiator contains at least (C1) an oxime ester-based photopolymerization initiator and (C2) an α-hydroxyketone-based photopolymerization initiator, the content of the (C1) oxime ester-based photopolymerization initiator in the (C) photopolymerization initiator is 51 to 95 mass%, and the content of the (Da) black pigment is 5 to 50 mass% based on the total solid content of the negative-type photosensitive resin composition.

[0005] Patent Document 3 discloses a black pigment dispersion composition containing lactam black, a purple pigment, a blue pigment and / or a green pigment, and carbon black.

[0006] Patent Document 4 discloses a photosensitive coloring composition containing at least (A) a coloring material, (B) a dispersant, (C) an alkali-soluble resin, and (D) a photopolymerization initiator, wherein the (A) coloring material is (A-1) a compound represented by a given formula (1), a geometric isomer thereof, a salt thereof, or a salt of the geometric isomer thereof. The (A-2) organic coloring pigment is included, and the (A-1) organic black pigment is contained in an amount of 30 to 90% by mass relative to 100% by mass of the (A) coloring material. The (A) coloring material is contained in an amount of 20% by mass or more relative to the total solid content in the photosensitive coloring composition. The (B) dispersant is a polymer dispersant having a quaternary ammonium base as a functional group.

[0007] Patent Document 5 discloses a photosensitive coloring composition containing (a) a colorant, (b) an alkali-soluble resin, (c) a photopolymerization initiator, (d) an ethylenically unsaturated compound, (e) a solvent, and (f) a dispersant, wherein the (a) colorant contains an organic black pigment that is a compound represented by a given formula, a geometric isomer thereof, a salt thereof, or a salt of the geometric isomer, and the (c) photopolymerization initiator contains an oxime ester compound having a diphenyl sulfide skeleton represented by another given formula.

[0008] Patent Document 6 discloses a colorant dispersion containing a colorant (E), wherein the colorant (E) contains a pigment (E1) and a dispersant (E2), and the dispersant (E2) contains a silsesquioxane compound having a structural unit represented by a given formula. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] International Publication No. 2020 / 017576 [Patent Document 2] International Publication No. 2019 / 150938 [Patent Document 3] Japanese Patent Application Publication No. 2019-81857 [Patent Document 4] Patent No. 6489008 [Patent Document 5] Patent No. 6528475 [Patent Document 6] Japanese Patent Application Publication No. 2018-70695 Summary of the Invention [Problem to be solved by the invention]

[0010] Generally, a transparent resin such as polyimide is used as the photosensitive resin in a resin composition for photolithography. Therefore, in order to prevent the electrical wiring from being visible through the bank, to prevent reflection, and to improve contrast, the resin composition for photolithography contains a colorant.

[0011] Therefore, the present invention provides a pigment dispersion for coloring a resin composition for photolithography. [Means for solving the problem]

[0012] The present inventors have conducted extensive research and found that the above problems can be solved by the following means, and have completed the present invention. That is, the present invention is as follows: <Embodiment 1> A pigment dispersion for coloring a resin composition for photolithography, comprising a pigment, an organic solvent, and an acid. Aspect 2: The pigment dispersion according to aspect 1, wherein the acid is an organic acid. Aspect 3: The pigment dispersion according to aspect 1 or 2, wherein the content of the acid is 0.005 to 40% by mass based on the mass of the pigment dispersion. Aspect 4: The pigment dispersion according to any one of Aspects 1 to 3, wherein the pigment is a benzofuranone-based pigment. <Aspect 5> A resin composition for photolithography, comprising the pigment dispersion according to any one of Aspects 1 to 4 and a photosensitive resin. [Effects of the Invention]

[0013] According to the present invention, a pigment dispersion for coloring a resin composition for photolithography can be provided. DETAILED DESCRIPTION OF THE INVENTION

[0014] Pigment dispersion The pigment dispersion of the present invention is a pigment dispersion for coloring a resin composition for photolithography, which contains a pigment, an organic solvent, and an acid.

[0015] The present inventors have found that when unnecessary portions of a resin composition for photolithography are removed to prepare a bank, the pigment of the resin composition for photolithography may remain on the substrate, particularly on the electrode surface of the substrate, which may have an undesirable effect on the resulting organic EL device.

[0016] In response to this, the present inventors have discovered that by further incorporating an acid into a resin composition for photolithography, the unnecessary portions can be rapidly dissolved during bank preparation, thereby reducing residues. This effect was unexpected, since alkaline fusion is generally used during bank preparation, and the presence of an acid is thought to inhibit this alkaline fusion.

[0017] Each component of the present invention will be described below.

[0018] Pigments Examples of the pigment that can be used include carbon-based pigments such as amorphous carbon powder, graphene, carbon nanotubes, graphite, and carbon black. Examples of the pigment that can be used include organic pigments such as benzofuranone pigments, azo pigments, condensed azo pigments, phthalocyanine pigments, anthraquinone pigments, quinacridone pigments, isoindolinone pigments, diketopyrrolopyrrole pigments, and various lake pigments.

[0019] As the pigment, it is preferable to use a black pigment from the viewpoint of hiding power.

[0020] The average particle size of the pigment may be 50 nm or more, 70 nm or more, 80 nm or more, 100 nm or more, 120 nm or more, 150 nm or more, 170 nm or more, 200 nm or more, 220 nm or more, 250 nm or more, 270 nm or more, or 300 nm or more, and may be 1000 nm or less, 800 nm or less, 700 nm or less, 600 nm or less, 550 nm or less, 500 nm or less, 450 nm or less, or 400 nm or less.

[0021] In this specification, the average particle size is the average particle size measured using dynamic light scattering. Specifically, this average particle size is the average particle size value measured using the cumulant method analysis of the scattering intensity distribution, calculated using a concentrated particle analyzer FPAR-1000 (Otsuka Electronics Co., Ltd.).

[0022] The pigment content in the pigment dispersion may be 5% by mass or more, 10% by mass or more, or 12% by mass or more, and may be 30% by mass or less, 25% by mass or less, 20% by mass or less, or 15% by mass or less, based on the mass of the pigment dispersion.

[0023] <Organic solvent> Examples of the organic solvent that can be used include aromatics, alcohols, polyhydric alcohols, glycol ethers, hydrocarbons, esters, etc. These solvents may be used alone or in combination.

[0024] Examples of aromatic compounds that can be used include benzyl alcohol, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, propylene glycol monophenyl ether, diethylene glycol monophenyl ether, alkylsulfonic acid phenyl ester, butyl phthalate, ethylhexyl phthalate, tridecyl phthalate, ethylhexyl trimellitate, diethylene glycol dibenzoate, and dipropylene glycol dibenzoate.

[0025] Examples of alcohols that can be used include ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butyl alcohol, 1-pentanol, isoamyl alcohol, sec-amyl alcohol, 3-pentanol, tert-amyl alcohol, n-hexanol, methylamyl alcohol, 2-ethylbutanol, n-heptanol, 2-heptanol, 3-heptanol, n-octanol, 2-octanol, 2-ethylhexanol, 3,5,5-trimethylhexanol, nonanol, n-decanol, undecanol, n-decanol, trimethylnonyl alcohol, tetradecanol, heptadecanol, cyclohexanol, and 2-methylcyclohexanol.

[0026] Examples of polyhydric alcohols that can be used include ethylene glycol, diethylene glycol, 3-methyl-1,3 butanediol, triethylene glycol, dipropylene glycol, 1,3 propanediol, 1,3 butanediol, 1,5 pentanediol, hexylene glycol, and octylene glycol.

[0027] Examples of glycol ethers that can be used include methyl isopropyl ether, ethyl ether, ethyl propyl ether, ethyl butyl ether, isopropyl ether, butyl ether, hexyl ether, 2-ethylhexyl ether, ethylene glycol monohexyl ether, ethylene glycol mono-2-ethylbutyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monobutyl ether, 3-methyl-3-methoxy-1-butanol, 3-methoxy-1-butanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol tertiary butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monobutyl ether, and tetrapropylene glycol monobutyl ether.

[0028] As the hydrocarbons, for example, straight-chain hydrocarbons such as hexane, isohexane, heptane, octane, nonane, and decane, and cyclic hydrocarbons such as cyclohexane, methylcyclohexane, and ethylcyclohexane can be used.

[0029] Examples of esters include propylene glycol methyl ether acetate, propylene glycol diacetate, 3-methyl-3-methoxybutyl acetate, propylene glycol ethyl ether acetate, ethylene glycol ethyl ether acetate, butyl formate, isobutyl formate, isoamyl formate, propyl acetate, butyl acetate, isopropyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, propyl propionate, isobutyl propionate, isoamyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, methyl isobutyrate, ethyl isobutyrate, propyl isobutyrate, Examples of usable surfactants include methyl valerate, ethyl valerate, propyl valerate, methyl isovalerate, ethyl isovalerate, propyl isovalerate, methyl trimethylacetate, ethyl trimethylacetate, propyl trimethylacetate, methyl caproate, ethyl caproate, propyl caproate, methyl caprylate, ethyl caprylate, propyl caprylate, methyl laurate, ethyl laurate, methyl oleate, ethyl oleate, caprylic acid triglyceride, tributyl acetate citrate, octyl oxystearate, propylene glycol monoricinoleate, methyl 2-hydroxyisobutyrate, and 3-methoxybutyl acetate.

[0030] <acid> The acid may be an inorganic acid or an organic acid.

[0031] Examples of inorganic acids that can be used include hydrochloric acid, perchloric acid, hydrofluoric acid, nitric acid, phosphoric acid, pyrophosphoric acid, polyphosphoric acid, sulfuric acid, boric acid, and tetrafluoroboric acid.

[0032] Examples of the organic acid that can be used include acetic acid, benzoic acid, phthalic acid, phenolsulfonic acid, benzenesulfonic acid, toluenesulfonic acid, meta-cresolsulfonic acid, resorcinolsulfonic acid, butylsulfonic acid, and propylsulfonic acid.

[0033] As the acid, it is particularly preferable to use an organic acid from the viewpoint of more effectively suppressing the generation of residues.

[0034] The content of the acid in the pigment dispersion may be, based on the mass of the pigment dispersion, 0.005% by mass or more, 0.01% by mass or more, 0.05% by mass or more, 0.1% by mass or more, 0.3% by mass or more, 0.5% by mass or more, 0.7% by mass or more, 0.9% by mass or more, 1.0% by mass or more, 1.5% by mass or more, 2.0% by mass or more, 2.5% by mass or more, 3.0% by mass or more, or 3.5% by mass or more, and may be 40.0% by mass or less, 35.0% by mass or less, 30.0% by mass or less, 25.0% by mass or less, 20.0% by mass or less, 18.0% by mass or less, 16.0% by mass or less, 14.0% by mass or less, 12.0% by mass or less, 10.0% by mass or less, 9.0% by mass or less, 8.0% by mass or less, 7.0% by mass or less, 6.0% by mass or less, or 5.0% by mass or less.

[0035] <Dispersant> Any dispersant can be used as the dispersant, and among them, it is preferable to use a urethane-based, acrylic-based, or polyester-based dispersant.

[0036] Specific examples of dispersants include "DISPERBYK" (registered trademark)-108, -109, -160, -161, -162, -163, -164, -166, -167, -168, -182, -184, -185, -2000, -2008, -2009, -2022, -2050, -2055, -2150, -2155, -2163, -2164, and -2061, "BYK" (registered trademark)-9075, -9077, -LP-N6919, -LP-N21116, and -LP-N21324 (all manufactured by BYK Japan), and "EFKA" (registered trademark). Examples of the antibacterial agent include 4015, 4020, 4046, 4047, 4050, 4055, 4060, 4080, 4300, 4330, 4340, 4400, 4401, 4402, 4403, and 4800 (all manufactured by BASF), "Ajisper" (registered trademark) PB711 (Ajinomoto (registered trademark) Fine Techno Co., Ltd.), and "SOLSPERSE" (registered trademark) 13240, 13940, 20000, 71000, and 76500 (all manufactured by Lubrizol).Further, "ANTI-TERRA" (registered trademark)-U100 or -204, "DISPERBYK" (registered trademark)-106, -140, -142, -145, -180, -2001, -2013, -2020, -2025, -187 or -191, "BYK" (registered trademark)-9076 (BYK Japan K.K., "Ajisper" (registered trademark) PB821, PB880 or PB881 (all of which are Ajinomoto Fine Techno Co., Ltd.), or "SOLSPERSE" (registered trademark) 9000, 11200, 13650, 24000, 32000, 32500, 32500, 32600, 33000, 34750, 35100, 35200, 37500, 39000, 56000, or 76500 (all manufactured by Lubrizol), "DISPERBYK" (registered trademark)-102, -110, -111, -118, -170, -171, -174, -2060, or -2096, "BYK" (registered trademark)-P104, -P105, or -220S (all manufactured by BYK Japan), or "SOLSPERSE" (registered trademark) 3000, 16000, 17000, 18000, 21000, 26000, 28000, 36000, 36600, 38500, 41000, 41090, 53095, or 55000 (all manufactured by Lubrizol), "DISPERBYK" (registered trademark) -103, -2152, -2200, or -192 (all manufactured by BYK Japan), or "SOLSPERSE" (registered trademark) 27000, 54000, or X300 (all manufactured by Lubrizol).

[0037] The content of the dispersant in the pigment dispersion may be, based on the mass of the pigment dispersion, converted into solid content, 0.25 mass% or more, 0.5 mass% or more, 1 mass% or more, 3 mass% or more, 5 mass% or more, 7 mass% or more, or 9 mass% or more, and may be 30 mass% or less, 25 mass% or less, 20 mass% or less, 15 mass% or less, or 10 mass% or less.

[0038] The content of the dispersant, in terms of solid content, relative to 100 parts by mass of the pigment, may be 10 parts by mass or more, 15 parts by mass or more, 20 parts by mass or more, 25 parts by mass or more, 30 parts by mass or more, 40 parts by mass or more, 45 parts by mass or more, 50 parts by mass or more, 55 parts by mass or more, 60 parts by mass or more, or 65 parts by mass or more, or may be 100 parts by mass or less, 90 parts by mass or less, 85 parts by mass or less, 80 parts by mass or less, 75 parts by mass or less, or 70 parts by mass or less.

[0039] <<Resin Composition for Photolithography>> The resin composition for photolithography of the present invention contains the above-mentioned pigment dispersion and a photosensitive resin.

[0040] A bank using this resin composition can be produced by, for example, negative or positive photolithography.

[0041] More specifically, in the case of negative photolithography, the resin composition is applied to a substrate for an organic EL element, for example, a substrate having an indium tin oxide (ITO) layer, to form a resin layer, and then the resin layer is exposed to light in areas corresponding to the banks, and then the resin layer is washed to remove (develop) the unexposed areas, thereby producing a bank.

[0042] In the case of positive photolithography, the resin composition is applied to a substrate for an organic EL element to form a resin layer, and then the resin layer is exposed to light in areas other than those corresponding to the bank, and the resin layer is then washed to remove (develop) the exposed areas, thereby producing a bank.

[0043] The pigment content in the resin composition for photolithography may be 0.5% by mass or more, 1% by mass or more, 2% by mass or more, 3% by mass or more, or 4% by mass or more, based on the mass of the resin composition for photolithography, and may be 15% by mass or less, 13% by mass or less, 11% by mass or less, 9% by mass or less, 7% by mass or less, 6% by mass or less, or 5% by mass or less.

[0044] The acid content in the resin composition for photolithography, based on the mass of the resin composition for photolithography, may be 0.0005% by mass or more, 0.001% by mass or more, 0.005% by mass or more, 0.01% by mass or more, 0.05% by mass or more, 0.1% by mass or more, 0.3% by mass or more, 0.5% by mass or more, 0.7% by mass or more, or 0.9% by mass or more, and may be 10% by mass or less, 8.0% by mass or less, 6.0% by mass or less, 5.0% by mass or less, 4.0% by mass or less, 3.0% by mass or less, 2.0% by mass or less, 1.5% by mass or less, 1.3% by mass or less, or 1.1% by mass or less.

[0045] <Photosensitive resin> As the photosensitive resin, for example, a negative photosensitive resin or a positive photosensitive resin can be used.

[0046] As taught in Patent Document 2, for example, a resin composition containing an alkali-soluble resin, a radical polymerizable compound, and a photopolymerization initiator can be used as the negative photosensitive resin.

[0047] Examples of alkali-soluble resins that can be used include polyimides, polyimide precursors, polybenzoxazoles, and polybenzoxazole precursors.

[0048] Examples of the radical polymerizable compound include diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, 1,3-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, dimethylol-tricyclodecane di(meth)acrylate, and pentaerythritol tri(meth)acrylate. acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol hepta(meth)acrylate, tripentaerythritol octa(meth)acrylate, tetrapentaerythritol nona(meth)acrylate, tetrapentaerythritol deca(meth)acrylate, pentaerythritol undeca(meth)acrylate, pentaerythritol dodeca(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, 2,2-bis[4-(3-(meth)acryloxy-2-hydroxypropoxy)phenyl]propane, 1,3,5-tris((meth)acryloxyethyl)isocyanuric acid, 1,3-bis((meth)acryloxyethyl)isocyanuric acid, or acid-modified products thereof can be used.

[0049] The photopolymerization initiator may be, for example, a photopolymerization initiator containing at least an oxime ester-based photopolymerization initiator and an α-hydroxyketone-based photopolymerization initiator.

[0050] The content of the photosensitive resin may be 20% by mass or more, 25% by mass or more, 30% by mass or more, 35% by mass or more, 40% by mass or more, 45% by mass or more, 50% by mass or more, 55% by mass or more, 60% by mass or more, 65% by mass or more, or 70% by mass or more, based on the total mass of the resin composition for photolithography, and may be 95% by mass or less, 90% by mass or less, 85% by mass or less, 80% by mass or less, or 75% by mass or less. [Example]

[0051] The present invention will be specifically explained with reference to examples and comparative examples, but the present invention is not limited to these.

[0052] <<Preparation of pigment dispersion liquid>> Example 1 A pigment dispersion of Example 1 was prepared by mixing 4.13 parts by mass of a pigment (Irgaphor (registered trademark) Black S0100CF, BASF), 2.69 parts by mass of a dispersant (DISPERBYK-2001, BYK, solid content 46% by mass), 19.68 parts by mass of propylene glycol monomethyl ether, and 1.00 parts by mass of phthalic acid.

[0053] Examples 2 to 10 and Comparative Examples 1 and 2 Pigment dispersions of Examples 2 to 10 and Comparative Examples 1 and 2 were prepared in the same manner as in Example 1, except that the type and content of each component was changed as shown in Table 1.

[0054] <<Creating the coating>> 2.75 parts by mass of each of the prepared pigment dispersions was mixed with 7.25 parts by mass of a photosensitive resin (DL-1000, Toray Industries, Inc.) to prepare a resin composition for photolithography.

[0055] The prepared resin composition was applied to a substrate having an indium tin oxide (ITO) layer to form a resin layer, and then the resin layer was exposed to light with an energy of 500 mJ at the locations corresponding to the positions of the banks.The resin layer was then washed with tetramethylammonium hydroxide as a developer to remove (develop) the resin layer in the areas other than the banks, thereby producing banks with a thickness of 1.2 μm.

[0056] <<Evaluation as a bank>> <Developing time ratio> The time required for development in Comparative Example 1, i.e., the time from when tetramethylammonium hydroxide was first brought into contact with the exposed resin composition until it was visually recognized that the exposed portion had been completely removed, was measured.

[0057] Next, the time required for development was measured in the other Examples and Comparative Examples in the same manner. The "Development time ratio (%)" in Table 1 indicates the percentage when the time required for bank formation in Comparative Example 1 is set to 100%.

[0058] <exterior> The appearance of the residue was confirmed by visual inspection: A: There is almost no residue. B: Some residue is present. C: Residue is present. D: Almost no residue was removed.

[0059] <Evaluation as an organic EL element> <Fabrication of organic EL elements> Using the banks obtained using the pigment dispersions of Comparative Examples 1 and 2 and Examples 1 and 4, organic EL devices for evaluation were fabricated in the same manner as in Patent Document 2.

[0060] Specifically, a nitrogen plasma treatment was performed as a pretreatment on the ITO layer serving as an anode on which the bank had been formed, and then a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport material, and a cathode were deposited in this order by vacuum deposition. The specific materials used for the hole injection layer, the hole transport layer, the light-emitting layer, the electron transport material, and the cathode were the same as those used in Patent Document 2.

[0061] <Light Emitting Characteristics 1> The organic EL elements prepared by the above method were stored at 85°C for 192 hours, and then lit at an applied voltage of 3.5V, and observed for luminance defects such as non-luminous areas and uneven brightness. Luminous areas where the brightness changed were considered to have uneven brightness, and areas where uneven brightness occurred were considered to have no light emission.

[0062] Observation was performed using a microscope (ECLIPSE LV150, Nikon Corporation). The objective lens used for the microscope was LU Plan Fluor 5x (Nikon Corporation).

[0063] The evaluation criteria are as follows: A: The light is emitted uniformly, with no uneven brightness. B: Light is emitted, but there is some unevenness in brightness. C: The light emission is weak and there is uneven brightness. D: Not emitting light.

[0064] <Light Emitting Characteristics 2> The organic EL device fabricated by the above method was made to emit light at an applied voltage of 5 V, and the light-emitting characteristics were evaluated based on changes in current.

[0065] As an index of the light-emitting properties, the change in current compared with an organic EL element fabricated using an uncolored (transparent) resin composition for photolithography (DL-1000, Toray Industries, Inc.), i.e., a resin composition for photolithography that does not contain a pigment (referred to as "Comparative Example 3" in Table 3), was calculated using the following formula. Current change = Yb / Yc Yb: Current density when using a photolithography resin composition containing a pigment dispersion Yc: Current density when using uncolored (transparent) photolithography resin composition (DL-1000)

[0066] The current density was measured by applying a voltage of 5.0 V using an IVL characteristic automatic measuring device ETS-170 (System Giken Co., Ltd.).

[0067] The evaluation criteria are as follows: A: 0.90 or higher B: 0.80 or more and less than 0.90 C: 0.60 or more and less than 0.80 D: Less than 0.60

[0068] Tables 1 to 3 show the configurations and evaluation results of the examples and comparative examples.

[0069] [Table 1]

[0070] [Table 2]

[0071] [Table 3]

Claims

1. A pigment dispersion for coloring a resin composition for photolithography, comprising a pigment, an organic solvent, and an acid, the acid is hydrochloric acid, perchloric acid, hydrofluoric acid, nitric acid, phosphoric acid, pyrophosphoric acid, polyphosphoric acid, sulfuric acid, boric acid, tetrafluoroboric acid, acetic acid, benzoic acid, phthalic acid, phenolsulfonic acid, benzenesulfonic acid, toluenesulfonic acid, meta-cresol sulfonic acid, resorcinol sulfonic acid, butylsulfonic acid, or propylsulfonic acid; the content of the acid is 1.5 to 40 mass% based on the mass of the pigment dispersion; Pigment dispersion.

2. The pigment dispersion of claim 1 , wherein the acid is acetic acid, benzoic acid, or phthalic acid.

3. A pigment dispersion for coloring a resin composition for photolithography, comprising a pigment, an organic solvent, and an acid, the acid is hydrochloric acid, perchloric acid, hydrofluoric acid, nitric acid, phosphoric acid, pyrophosphoric acid, polyphosphoric acid, sulfuric acid, boric acid, or tetrafluoroboric acid; Pigment dispersion.

4. 4. The pigment dispersion according to claim 1, wherein the content of the acid is 3.5 to 40 mass % based on the mass of the pigment dispersion.

5. The pigment dispersion according to any one of claims 1 to 4, wherein the pigment is a benzofuranone-based pigment.

6. A resin composition for photolithography, comprising the pigment dispersion according to any one of claims 1 to 5 and a photosensitive resin.

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