Display black pigment dispersion composition, display black pigment dispersion resist composition, and black resist film

Abstract

To provide a display black pigment dispersion composition, a display black pigment dispersion resist composition, and a black resist film, which enable formation of coating films with superior viscosity stability and superior solvent resistance to highly polar solvents such as N-methylpyrrolidone.SOLUTION: A display black pigment dispersion composition is provided, containing lactam black, a polymeric pigment dispersant which is a random copolymer having nitrogen atoms, a first alkali-soluble resin, and a solvent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a black pigment dispersion composition for displays, a black pigment dispersion resist composition for displays, and a black resist film. More specifically, the present invention relates to a black pigment dispersion composition for displays, a black pigment dispersion resist composition for displays, and a black resist film that can form a coating film that can achieve both solvent resistance to highly polar solvents such as N-methylpyrrolidone and an excellent break point. [Background technology]

[0002] To date, black matrices, black photospacers, black column spacers, and black pigment dispersion compositions for displays used to form these have been developed to improve the quality, contrast, performance, etc. of liquid crystal displays. Patent Document 1 discloses a black colored composition that preferably uses a combination of carbon black and lactam black, and further disperses a specified pigment using a pigment dispersant and a dispersion aid. Patent Document 2 discloses a black pigment dispersion composition that uses a combination of lactam black and carbon black, and is blended with specified purple, blue, and green pigments. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6914807 [Patent Document 2] Patent No. 7080618 Summary of the Invention [Problem to be solved by the invention]

[0004] The alignment film that constitutes a display is formed by applying a solution in which polyamic acid, a precursor of polyimide resin, is dissolved in a basic solvent with very high solubility, such as N-methylpyrrolidone (NMP). Therefore, parts that come into contact with the alignment film (such as black matrices, black photospacers, and black column spacers) are required to be resistant to highly polar solvents such as NMP. However, the pigment dispersion compositions described in Patent Documents 1 and 2 all have room for improvement in terms of solvent resistance to solvents such as NMP. Furthermore, these pigment dispersants have problems such as a tendency for viscosity to change over time and a poor break point.

[0005] The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a black pigment dispersion composition for displays, a black pigment dispersion resist composition for displays, and a black resist film that are capable of forming a coating film that can achieve both solvent resistance to highly polar solvents such as N-methylpyrrolidone and an excellent break point. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above problems and have found that the above problems can be solved simultaneously by combining lactam black, a random copolymer having a nitrogen atom, a first alkali-soluble resin, and a solvent, thereby completing the present invention. The present invention, which solves the above problems, mainly comprises the following features.

[0007] (1) A black pigment dispersion composition for displays, comprising lactam black, a polymeric pigment dispersant which is a random copolymer having nitrogen atoms, a first alkali-soluble resin, and a solvent.

[0008] According to this configuration, the black pigment dispersion composition for displays can form a coating film that can achieve both solvent resistance to highly polar solvents such as N-methylpyrrolidone and an excellent break point.

[0009] (2) The black pigment dispersion composition for displays according to (1), further comprising a sulfonic acid group-containing pigment dispersion aid.

[0010] According to this configuration, the black pigment dispersion composition for displays can form a coating film having excellent solvent resistance against highly polar solvents such as N-methylpyrrolidone.

[0011] (3) A black pigment dispersion resist composition for displays, comprising the black pigment dispersion composition for displays according to (1) or (2), a second alkali-soluble resin, a photopolymerizable compound, and a photopolymerization initiator, wherein the second alkali-soluble resin comprises an alkali-soluble resin having a crosslinkable functional group.

[0012] According to this configuration, the black pigment dispersion resist composition for displays can form a coating film that has excellent solvent resistance against highly polar solvents such as N-methylpyrrolidone. Furthermore, the black pigment dispersion resist composition for displays has excellent development adhesion even when forming fine lines, making it possible to obtain a high-definition display.

[0013] (4) A black resist film formed from the black pigment dispersed resist composition for displays according to (3).

[0014] With this configuration, the black resist film has superior solvent resistance to highly polar solvents such as N-methylpyrrolidone. Furthermore, the black resist film has excellent development adhesion even when fine lines are formed, making it possible to obtain a high-definition display. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a black pigment dispersion composition for displays, a black pigment dispersion resist composition for displays, and a black resist film, which are capable of forming a coating film that has excellent viscosity stability and excellent solvent resistance against highly polar solvents such as N-methylpyrrolidone. DETAILED DESCRIPTION OF THE INVENTION

[0016] <Black pigment dispersion composition for displays> A black pigment dispersion composition for displays (hereinafter also referred to as a pigment dispersion composition) according to one embodiment of the present invention contains lactam black, a polymeric pigment dispersant that is a random copolymer having nitrogen atoms, a first alkali-soluble resin, and a solvent. Each of these components will be described below.

[0017] (Lactam Black) The lactam black may be any known lactam black. For example, the lactam black of this embodiment has the following main skeleton, and more specifically, is Irgaphor Black S 0100 CF (manufactured by DIC Corporation). When the lactam black has the following main skeleton, hydrogen atoms in the main skeleton may be appropriately substituted with low-molecular-weight functional groups (for example, hydrocarbon groups such as alkyl groups, alkenyl groups, and alkynyl groups; acidic groups such as carboxyl groups, sulfonic acid groups, and phosphonic acid groups; basic groups such as amino groups; hydroxyl groups; etc.) or halogen atoms.

[0018] [ka]

[0019] The volume-based particle size D50 of the lactam black of this embodiment is preferably 70 nm or more, more preferably 85 nm or more. Furthermore, the D50 value is preferably 130 nm or less, more preferably 115 nm or less. By having a D50 value within the above range, the pigment in the resulting pigment dispersion composition is less likely to settle and has good viscosity stability. Furthermore, the pigment dispersion composition provides a resist film with good linearity and roughness.

[0020] The volume-based particle size D90 of lactam black is preferably 160 nm or more, more preferably 180 nm or more. Furthermore, the D90 value is preferably 300 nm or less, more preferably 280 nm or less. By having the D90 value within the above range, the pigment in the resulting pigment dispersion composition is less likely to settle and has good viscosity stability. Furthermore, the resulting pigment dispersion composition provides a resist film with good linearity and roughness.

[0021] In this embodiment, the volume-based particle size can be measured by a laser diffraction particle size measurement method using Nanotrac (UPA-EX150, manufactured by Nikkiso Co., Ltd.).

[0022] The content of lactam black is not particularly limited. For example, the content of lactam black in the pigment dispersion composition is preferably 3% by mass or more, more preferably 5% by mass or more. Furthermore, the content of lactam black in the pigment dispersion composition is preferably 25% by mass or less, more preferably 20% by mass or less. When the content of lactam black is within the above range, the pigment dispersion composition provides a resist film with good OD value and development adhesion.

[0023] (Polymer pigment dispersant, a random copolymer containing nitrogen atoms) The polymeric pigment dispersant (hereinafter also referred to as polymeric pigment dispersant) which is a random copolymer having nitrogen atoms is not particularly limited. For example, the polymeric pigment dispersant is a nitrogen-containing graft copolymer. This makes it easier to obtain a high-resolution display using the pigment dispersion composition.

[0024] The main chain of the graft copolymer having a nitrogen atom may be linear or branched.

[0025] The amine value of the nitrogen-containing graft copolymer is preferably 60 mgKOH / g or less, and more preferably 40 mgKOH / g or less. When the amine value is within the above range, the pigment dispersion composition has better viscosity stability.

[0026] Commercially available products of the graft copolymer having nitrogen atoms include LPN21324 (manufactured by BYK-Chemie), S-reem AD-374M, and S-reem AD-3172M.

[0027] The weight-average molecular weight of the polymeric pigment dispersant, measured by GPC in terms of polystyrene, is preferably at least 3,000, and more preferably at least 5,000. The weight-average molecular weight of the polymeric pigment dispersant is preferably at most 100,000, and more preferably at most 50,000. When the weight-average molecular weight is within the above range, the pigment dispersion composition has excellent viscosity stability.

[0028] The content of the polymeric pigment dispersant is not particularly limited. For example, the content of the polymeric pigment dispersant in the pigment dispersion composition is preferably 1.0% by mass or more, and more preferably 3.0% by mass or more. Furthermore, the content of the polymeric pigment dispersant in the pigment dispersion composition is preferably 8.0% by mass or less, and more preferably 6.0% by mass or less. When the content of the polymeric pigment dispersant is within the above range, the pigment dispersion composition has excellent viscosity stability and solvent resistance.

[0029] (Acidic group-containing pigment dispersing aid) The pigment dispersion composition of this embodiment preferably contains an acidic group-containing pigment dispersing aid for the purpose of improving the dispersibility of the pigment.

[0030] The acidic group-containing pigment dispersing aid is not particularly limited. Examples of the acidic group-containing pigment dispersing aid include perylene compounds, diketopyrrolopyrrole compounds, azonaphthol compounds, dioxazine compounds, quinacridone compounds, phthalocyanine compounds and their metal complexes, compounds in which an acidic group such as a carboxyl group or a sulfonic acid group has been introduced into a pigment such as an anthraquinone, naphthalene, acridone, or triazine (dye derivatives having an acidic group), and compounds in which such a compound has been neutralized with an organic amine or the like. Among these, the pigment dispersion composition of this embodiment preferably contains a sulfonic acid group-containing pigment dispersing aid. This allows the pigment dispersion composition to form a coating film with excellent solvent resistance to highly polar solvents such as N-methylpyrrolidone.

[0031] The sulfonic acid group-containing pigment dispersing aid preferably contains at least one of sulfonated Pigment Red 2, sulfonated Pigment Blue 15, sulfonated Pigment Yellow 138, and sulfonated Pigment Violet 23. This enables the pigment dispersion composition to form a coating film with even better solvent resistance to highly polar solvents such as N-methylpyrrolidone.

[0032] The content of the acidic group-containing pigment dispersing aid is preferably 1.0 part by mass or more, more preferably 1.5 parts by mass or more, per 100 parts by mass of lactam black. Furthermore, the content of the acidic group-containing pigment dispersing aid is preferably 5.0 parts by mass or less, more preferably 4.0 parts by mass or less, per 100 parts by mass of lactam black. This allows the pigment dispersion composition to form a coating film with even better solvent resistance to highly polar solvents such as N-methylpyrrolidone.

[0033] (First alkali-soluble resin) The first alkali-soluble resin is blended to form a partition wall pattern of a color filter in black matrix applications, and to form a partition wall pattern of a color filter and a spacer of a liquid crystal layer in black photospacer and black column spacer applications.

[0034] The first alkali-soluble resin is not particularly limited. Examples include acrylic copolymer resins, maleic acid copolymer resins, polyester resins obtained by condensation polymerization, epoxy acrylate resins obtained by addition polymerization of acrylic acid and an epoxy compound, and urethane acrylate resins obtained by polymerization of acrylic acid, a polyol, and an isocyanate compound. This makes it easier to obtain a high-resolution display using the pigment dispersion composition. Among these, the first alkali-soluble resin is preferably an acrylic copolymer resin or an epoxy acrylate resin because of its excellent developability and development adhesion.

[0035] The first alkali-soluble resin is not particularly limited. For example, the first alkali-soluble resin is a resin containing an anionic group such as a carboxyl group, a sulfonic acid group, or a phosphonic acid group (-P(=O)(OH)).

[0036] The acrylic resin is not particularly limited, and examples thereof include the "Pholette" series manufactured by Soken Chemical & Engineering Co., Ltd., such as ZAH-106, ZAH-110, ZAH-115, and ZAH-310.

[0037] The epoxy acrylate resin is not particularly limited. Examples of epoxy acrylate resins include the "KAYARAD" series manufactured by Nippon Kayaku Co., Ltd., CCR-1291H, CCR-1235, ZAR-1035, ZAR-2000, ZFR-1401H, ZFR-1491H, ZCR-1569H, ZCR-1601H, ZCR-1797H, ZCR-1798H, UXE-3000, and UXE-3024.

[0038] The urethane acrylate resin is not particularly limited, and examples thereof include the "KAYARAD" series manufactured by Nippon Kayaku Co., Ltd., such as UX-3204, UX-4101, UXT-6100, UX-8101, UX-0937, DPHA-40H, and UX-5000.

[0039] From the viewpoint of alkali developability, the acid value of the first alkali-soluble resin is preferably 10 mgKOH / g or more, more preferably 20 mgKOH / g or more, and is preferably 300 mgKOH / g or less, more preferably 200 mgKOH / g or less.

[0040] The weight-average molecular weight of the first alkali-soluble resin is preferably 1,000 or more, more preferably 3,000 or more, from the viewpoint of film-forming properties such as resist films. Furthermore, the weight-average molecular weight of the alkali-soluble resin is preferably 100,000 or less, more preferably 50,000 or less, from the viewpoint of improving solubility. The weight-average molecular weight can be measured by gel permeation chromatography (GPC). For example, chromatography can be performed using a Water 2690 (manufactured by Waters) GPC apparatus and a PLgel 5μ MIXED-D (manufactured by Polymer Laboratories) column under the following conditions: tetrahydrofuran as the developing solvent, a column temperature of 25°C, a flow rate of 1 milliliter / minute, an RI detector, a sample injection concentration of 10 milligrams / milliliter, and an injection volume of 100 microliters, and the weight-average molecular weight can be calculated as polystyrene equivalent.

[0041] The content of the first alkali-soluble resin is not particularly limited. For example, the content of the first alkali-soluble resin is preferably 5 parts by mass or more, and more preferably 10 parts by mass or more, per 100 parts by mass of lactam black. Furthermore, the content of the first alkali-soluble resin is preferably 90 parts by mass or less, and more preferably 80 parts by mass or less, per 100 parts by mass of lactam black. When the content of the first alkali-soluble resin is within the above range, the pigment dispersion composition is likely to produce a high-definition display.

[0042] (solvent) The pigment dispersion composition of the present embodiment contains a solvent. The solvent is not particularly limited. For example, from the viewpoint of stably dispersing lactam black and sufficiently dissolving the first alkali-soluble resin and the like, the solvent is preferably an ester-based solvent, an ether-based solvent, an ether ester-based solvent, a ketone-based solvent, an aromatic hydrocarbon-based solvent, or a nitrogen-containing solvent.

[0043] Examples of ester solvents include methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, 3-methyl-3-methoxybutylpropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl ethoxyacetate, hydroxyacetic acid esters, and n-amyl formate.

[0044] Examples of the ether solvent include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, and diethylene glycol methyl ethyl ether.

[0045] Examples of the ether ester solvent include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, and propylene glycol monoethyl ether acetate.

[0046] The ketone solvents include methyl isobutyl ketone, cyclohexanone, 2-heptanone, and δ-butyrolactone.

[0047] The aromatic hydrocarbon solvents include toluene, xylene, and alkylnaphthalene.

[0048] The nitrogen-containing solvents include N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0049] When a solvent is contained, the content of the solvent is not particularly limited. For example, the content of the solvent in the pigment dispersion composition is preferably 40% by mass or more, and more preferably 50% by mass or more. Furthermore, the content of the solvent in the pigment dispersion composition is preferably 90% by mass or less, and more preferably 80% by mass or less. When the content of the solvent is within the above range, the pigment dispersion composition has excellent dispersion stability of lactam black.

[0050] Returning to the description of the pigment dispersion composition as a whole, the method for preparing the pigment dispersion composition of the present embodiment is not particularly limited. For example, the pigment dispersion composition can be prepared by mixing various materials and kneading the mixture overnight using a bead mill or the like.

[0051] As described above, the pigment dispersion composition of this embodiment has excellent viscosity stability and can form a coating film that has excellent solvent resistance to highly polar solvents such as N-methylpyrrolidone. Therefore, the pigment dispersion composition is suitable for displays, and is particularly suitable for black matrices, black photospacers, black column spacers, and the like. Specifically, when the pigment dispersion composition of this embodiment is used for black matrices, black photospacers, or black column spacers, the display is less likely to malfunction and is less susceptible to deterioration.

[0052] <Black pigment-dispersed resist composition for displays> A black pigment dispersion resist composition for displays (hereinafter also referred to as a resist composition) according to one embodiment of the present invention contains the above-described black pigment dispersion composition for displays, a second alkali-soluble resin, a photopolymerizable compound, and a photopolymerization initiator. The second alkali-soluble resin may be the same as the first alkali-soluble resin. The second alkali-soluble resin preferably contains an alkali-soluble resin having a crosslinkable functional group. Each of these components will be described below.

[0053] (Black pigment dispersion composition for displays) The black pigment dispersion composition for displays (hereinafter also referred to as pigment dispersion composition) is as described above, and therefore the description will be omitted where appropriate.

[0054] The content of the pigment dispersion composition is not particularly limited. For example, the content of the pigment dispersion composition is preferably 20% by mass or more, and more preferably 30% by mass or more. Furthermore, the content of the pigment dispersion composition is preferably 60% by mass or less, and more preferably 50% by mass or less. When the content of the pigment dispersion composition is within the above range, the resist composition is likely to achieve both development adhesion and an OD value.

[0055] (First alkali-soluble resin) The first alkali-soluble resin is the same as described above, and therefore a description thereof will be omitted.

[0056] (Second alkali-soluble resin) The second alkali-soluble resin is blended to improve the developability with an alkaline developer and the solvent resistance. There are no particular limitations on the second alkali-soluble resin, as long as it is an alkali-soluble resin having a crosslinking functional group. For example, the second alkali-soluble resin is an alkali-soluble resin having a crosslinking functional group among the first alkali-soluble resins described above in relation to the pigment dispersion composition. Specifically, the second alkali-soluble resin is preferably an epoxy acrylate resin, an epoxy resin, an acrylic resin, or a urethane resin, and more preferably an epoxy acrylate resin.

[0057] The content of the second alkali-soluble resin is not particularly limited. For example, the content of the second alkali-soluble resin in the resist composition is preferably 3% by mass or more, and more preferably 5% by mass or more. Furthermore, the content of the second alkali-soluble resin in the resist composition is preferably 15% by mass or less, and more preferably 12% by mass or less. By keeping the content of the second alkali-soluble resin within the above range, the resist composition has an appropriate range of developability with an alkaline developer.

[0058] (Photopolymerizable compound) The photopolymerizable compound is not particularly limited, and examples thereof include monomers and oligomers having a photopolymerizable unsaturated bond.

[0059] Examples of the monomer having one photopolymerizable unsaturated bond include alkyl methacrylates or acrylates such as methyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, methyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; aralkyl methacrylates or acrylates such as benzyl methacrylate and benzyl acrylate; alkoxyalkyl methacrylates or acrylates such as butoxyethyl methacrylate and butoxyethyl acrylate; and aminoalkyl methacrylates such as N,N-dimethylaminoethyl methacrylate and N,N-dimethylaminoethyl acrylate. Methacrylates or acrylates; methacrylic acid esters or acrylic acid esters of polyalkylene glycol monoalkyl ethers such as diethylene glycol monoethyl ether, triethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, etc.; methacrylic acid esters or acrylic acid esters of polyalkylene glycol monoaryl ethers such as hexaethylene glycol monophenyl ether; isobornyl methacrylate or acrylate; glycerol methacrylate or acrylate; 2-hydroxyethyl methacrylate or acrylate, etc.

[0060] Monomers having two or more photopolymerizable unsaturated bonds include bisphenol A dimethacrylate, 1,4-butanediol dimethacrylate, 1,3-butylene glycol dimethacrylate, diethylene glycol dimethacrylate, glycerol dimethacrylate, neopentyl glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol tetramethacrylate, dipentaerythritol hexamethacrylate, and dipentaerythritol tetramethacrylate. Examples of such acrylates include erythritol pentamethacrylate, bisphenol A diacrylate, 1,4-butanediol diacrylate, 1,3-butylene glycol diacrylate, diethylene glycol diacrylate, glycerol diacrylate, neopentyl glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, tetraethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, and dipentaerythritol pentaacrylate.

[0061] The oligomer having a photopolymerizable unsaturated bond is obtained by appropriately polymerizing the above-mentioned monomers, for example.

[0062] The content of the photopolymerizable compound is not particularly limited. For example, the content of the photopolymerizable compound in the resist composition is preferably 1% by mass or more, and more preferably 2.5% by mass or more. Furthermore, the content of the photopolymerizable compound in the resist composition is preferably 15% by mass or less, and more preferably 10% by mass or less. By having the content of the photopolymerizable compound within the above range, the resist composition is likely to achieve both curability and alkaline developability of the resist film.

[0063] (Photopolymerization initiator) The photopolymerization initiator is not particularly limited. Examples of the photopolymerization initiator include benzophenone, N,N'-tetraethyl-4,4'-diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, benzil, 2,2-diethoxyacetophenone, benzoin, benzoin methyl ether, benzoin isobutyl ether, benzil dimethyl ketal, α-hydroxyisobutylphenone, thioxanthone, 2-chlorothioxanthone, 1-hydroxycyclohexyl phenyl ketone, t-butylanthraquinone, 1-chloroanthraquinone, 2,3-dichloroanthraquinone, 3-chloro-2-methylanthraquinone, 2-ethylanthraquinone, 1,4-naphthoquinone, 1,2-benzoanthraquinone, 1,4-dimethylanthraquinone, 2-phenylanthraquinone, triazine-based photopolymerization initiators, and oxime ester-based photopolymerization initiators.

[0064] The content of the photopolymerization initiator is not particularly limited. For example, the content of the photopolymerization initiator in the resist composition is preferably 0.1% by mass or more, and more preferably 0.3% by mass or more. Furthermore, the content of the photopolymerization initiator in the resist composition is preferably 5% by mass or less, and more preferably 2% by mass or less. By keeping the content of the photopolymerization initiator within the above range, the resist composition is likely to achieve both the curability and fine line adhesion of the resist film.

[0065] Furthermore, additives such as a leveling agent, an antioxidant, and an antifoaming agent may be added to the resist composition as needed.

[0066] There are no particular limitations on the method for preparing the resist composition of this embodiment. As an example, the resist composition can be prepared by co-dispersing various materials using a stirring device or the like.

[0067] The resist composition of this embodiment has excellent viscosity stability. Furthermore, the resist composition can suppress a decrease in OD value (optical density) during the waiting time between resist application to a substrate and pre-baking. The resulting resist film has low reflectance and excellent development adhesion, allowing for the production of high-definition displays.

[0068] <Black resist film> A black resist film according to one embodiment of the present invention is a black resist film formed from the above-described black pigment dispersed resist composition for displays.

[0069] The method for forming the black resist film is not particularly limited. For example, the black resist film can be obtained by a known means using the above-mentioned black pigment-dispersed resist composition for displays. Specifically, the black resist film can be obtained by applying the above-mentioned resist composition to a transparent substrate, drying it to form a coating film, placing a photomask on the coating film, and then performing image exposure through the photomask, development, and, if necessary, photocuring, etc., to form a black matrix.

[0070] The substrate is not particularly limited, and examples thereof include a glass substrate, a silicon substrate, a polycarbonate substrate, a polyester substrate, a polyamide substrate, a polyamideimide substrate, a polyimide substrate, an aluminum substrate, a printed wiring board, and an array substrate.

[0071] The methods for applying, drying, exposing, and developing the resist composition can be appropriately selected from known methods.

[0072] Examples of methods for applying the resist composition include screen printing, roll coating, curtain coating, spray coating, and spin coating. After applying the resist composition, the applied layer may be heated, if necessary, using a heating means such as a circulation oven, an infrared heater, or a hot plate to volatilize the solvent contained in the resin layer. Heating conditions may be appropriately set depending on the composition of the resist composition used. Generally, heating conditions are a temperature of 50°C to 120°C for 30 seconds to 30 minutes.

[0073] The thickness of the coating film (after drying) is not particularly limited. For example, the thickness of the coating film is preferably 0.2 to 10 μm, more preferably 0.5 to 6 μm, and even more preferably 1 to 4 μm. When the thickness of the coating film is within the above range, the resulting black matrix is ​​likely to be favorably developed into a predetermined pattern and exhibit a predetermined optical density.

[0074] The exposure method is not particularly limited. For example, the exposure method is irradiation with active energy rays such as ultraviolet rays and excimer laser light. The amount of energy radiation may be appropriately set depending on the composition of the resist composition. For example, the energy dye may be irradiated with an amount of 30 to 2000 mJ / cm. 2 The light source used for exposure is not particularly limited. Examples of the light source include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, a xenon lamp, and a metal halide lamp.

[0075] The alkaline developer used for development is not particularly limited. Examples of the developer include aqueous solutions of sodium carbonate, potassium carbonate, calcium carbonate, sodium hydroxide, potassium hydroxide, etc.; aqueous solutions of amine compounds such as ethylamine, diethylamine, and dimethylethanolamine; and aqueous solutions of p-phenylenediamine compounds such as tetramethylammonium, 3-methyl-4-amino-N,N-diethylaniline, 3-methyl-4-amino-N-ethyl-N-β-hydroxyethylaniline, 3-methyl-4-amino-N-ethyl-N-β-methanesulfonamidoethylaniline, and 3-methyl-4-amino-N-ethyl-N-β-methoxyethylaniline, and sulfates, hydrochlorides, or p-toluenesulfonates thereof. The alkaline developer may contain, as needed, an antifoaming agent, a surfactant, or the like.

[0076] After the alkali development, the resin can be hardened by post-baking. The post-baking conditions are not particularly limited. For example, the post-baking conditions are a temperature of 80°C to 250°C and a time of 10 minutes to 4 hours.

[0077] As described above, the black resist film of this embodiment is obtained using a resist composition containing the pigment dispersion composition described above. Therefore, the black resist film has superior solvent resistance to highly polar solvents such as N-methylpyrrolidone. Furthermore, the black resist film has excellent development adhesion even when fine lines are formed, making it possible to obtain a high-definition display. Therefore, the black resist film is suitable for use in image display devices, touch panels, and the like that use high-definition displays. [Example]

[0078] The present invention will be described in more detail below with reference to examples. The present invention is not limited to these examples. Unless otherwise specified, "%" means "% by mass" and "parts" means "parts by mass."

[0079] The raw materials used are shown below. <Lactam Black> Irgaphor BLACK: S0100CF: (DIC Corporation) <Polymer pigment dispersant, a random copolymer containing nitrogen atoms> LPN21324: (Manufactured by BYK Co., Ltd.), nitrogen atom-containing graft copolymer (random copolymer containing quaternary amino groups), amine value 0 mg KOH / g, solid content 40% by mass ESLEEME AD-374M: (NOF Corporation), nitrogen atom-containing graft copolymer (random copolymer containing tertiary amino groups), amine value 30-40 mg KOH / g, solid content 100% by mass ESLEEME AD-3172M: (NOF Corporation), nitrogen atom-containing graft copolymer (random copolymer containing tertiary amino groups), amine value 30-42 mg KOH / g, solid content 100% by mass <Polymer pigment dispersant, a block copolymer containing nitrogen atoms> LPN6919: (Manufactured by BYK Co., Ltd.), nitrogen atom-containing block copolymer (block copolymer containing tertiary amino groups), amine value 120 mg KOH / g, solid content 60% by mass <Acidic group-containing pigment dispersing aid> PR2 sulfonated compound: (in-house produced) (Production method of PR2 sulfonated compound) A 100 ml square flask was charged with 30 ml of concentrated sulfuric acid, and while stirring with a magnetic stirrer, 10 g of CI Pigment Red 2 was added and stirred at room temperature for 30 minutes. A mixture of 50 g of water and 50 g of ice was placed in a 1 L beaker, and the above reaction product was poured into the ice water and stirred with a magnetic stirrer for 30 minutes. This was filtered and washed under reduced pressure, and the resulting solid was dried to produce a sulfonic acid group-containing pigment dispersing aid (sulfonated CI Pigment Red 2). P.Y138 sulfonated compound: (manufactured in-house) (P.Y138 Sulfonated Compound Manufacturing Method) A 100ml Erlenmeyer flask was charged with 20ml of concentrated sulfuric acid, and while stirring with a magnetic stirrer, 10g of Pigment Yellow 138 and 20ml of 28% fuming sulfuric acid were added, followed by stirring at 100-110°C for 240 minutes. A mixture of 50g of water and 50g of ice was placed in a 1L beaker, and the above reaction mixture was poured into the ice water and stirred with a magnetic stirrer for 30 minutes. This was filtered and washed under reduced pressure, and the resulting solid was dried to yield 11g of the desired sulfonic acid group-containing pigment dispersing aid (P.Y138 sulfonated product). Solsperse 5000S (PB15 sulfonated): (manufactured by Lubrizol Japan Co., Ltd.) Solsperse 12000J (PB15 sulfonated): (manufactured by Lubrizol Japan Co., Ltd.) PV23 sulfonate: (in-house production) (Production method of PV23 sulfonated product) In the manufacturing method of the PR2 sulfonated product, CI Pigment 2 was replaced with CI Pigment Violet 23, to prepare a sulfonic acid group-containing pigment dispersing aid (sulfonated product of CI Pigment Violet 238). <First alkali-soluble resin> ZAH-110: (Soken Chemical & Engineering Co., Ltd.), alkali-soluble acrylic resin, Foret ZAH-110, acid value 100 mg KOH / g, weight-average molecular weight approximately 15,000, solid content 35% by mass <Second alkali-soluble resin> ZCR-1569H: (Nippon Kayaku Co., Ltd.), alkali-soluble epoxy acrylate resin, KAYARAD ZCR-1569H, acid value 98 mg KOH / g, weight-average molecular weight approximately 4,500, solid content 70% by mass <Photopolymerizable compound> DPHA: Dipentaerythritol hexaacrylate <Photopolymerization initiator> IRGACURE OXE02: (BASF Japan Ltd.), oxime ester photoinitiator, IRGACURE OXE02 <Surface modifier> MF-554: (manufactured by DIC Corporation), Megafac F-554, fluorine-containing group and lipophilic group-containing oligomer, solid content 100% <Solvent> PGME: Propylene glycol monomethyl ether PGMEA: Propylene glycol monomethyl ether acetate

[0080] <Preparation of black pigment dispersion composition for display> (Preparation Examples 1 to 11, Comparative Preparation Examples 1 to 3) Mix various materials so that the composition in Table 1 (in terms of solid content, unit: mass%) is obtained, knead with a bead mill for a whole day and night, and prepare the black pigment dispersion compositions for display of Preparation Examples 1 to 11 and Comparative Preparation Examples 1 to 3.

[0081]

Table 1

[0082] <Examples 1 to 11, Comparative Examples 1 to 3> (Black pigment dispersion resist composition for display) Mix various materials so that the composition in Table 2 (unit: mass%) is obtained, mix uniformly using a high-speed stirrer, and then filter with a filter having a pore size of 3 μm to obtain the black pigment dispersion resist compositions for display of Examples 1 to 11 and Comparative Example 1.

[0083] Using the obtained black pigment dispersion resist composition for display, evaluate the change amount of optical density (OD value), breakpoint, development adhesion, viscosity stability and solvent resistance by the following method. The results are shown in Table 2.

[0084] <OD value (optical density)> Each black pigment-dispersed resist composition for displays was applied to a glass substrate (Corning, Eagle XG) using a spin coater to a film thickness of 1 μm. After pre-baking at 100°C for 3 minutes, the substrate was exposed to a high-pressure mercury lamp and post-baked at 230°C for 30 minutes, resulting in a black resist pattern formed only in the solid areas. The optical density (OD value) of each resulting black resist pattern in the solid areas was measured using a transmission densitometer (Ihac-T5, product name, Ihara Electronics Co., Ltd.). The OD value was measured at eight locations and corrected for film thickness and pigment concentration. The average OD value excluding the maximum and minimum values ​​was used as the optical density. The coating was also scraped with a utility knife, and the film thickness at the OD value measurement points was measured. Corrected OD value = measured OD value x 15.0 / pigment concentration x 1.0 / measured film thickness value A corrected OD value of 1.2 or more was considered acceptable. <Breakpoint and development adhesion> The black pigment dispersion resist compositions for displays prepared in each of the Examples and Comparative Examples were applied to a glass substrate (EAGLE XG) using a spin coater to a film thickness of 3.5 μm, and then prebaked at 100° C. for 3 minutes. Next, using a photomask having a line pattern with a line width of 1 μm to 100 μm, the resist compositions were exposed to UV light at a cumulative dose of 50 mJ / cm using a high-pressure mercury lamp. 2 After that, the film was exposed to light at 1 kgf / cm in a 0.05% aqueous potassium hydroxide solution at 23°C. 2 The time when the development pattern started to appear in the shower development at a pressure of 1 kgf / cm was taken as the breakpoint. In the evaluation of development adhesion, development was stopped when the time reached 1.5 times the breakpoint. 2 The glass substrate was then washed with high-pressure spray water, and the size (μm) of the smallest line pattern remaining on the glass substrate was evaluated. A smallest line pattern size of 20 μm or less was deemed to be acceptable. <Viscosity stability> The black pigment dispersion compositions for displays prepared in each of the Examples and Comparative Examples were placed in glass bottles, sealed, and stored for one week at 60° C. Before and after storage, the viscosity at 25° C. was measured using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., model RE100L) to determine the rate of viscosity change, which was then evaluated according to the following evaluation criteria. Viscosity change rate = [(viscosity after 1 week of storage - viscosity before storage) / (viscosity before storage)] Evaluation criteria ○: The viscosity change rate was 10% or less. △: The viscosity change rate was more than 10% and 20% or less. ×: The viscosity change rate exceeded 20%. <Solvent resistance> The black pigment-dispersed resist compositions for displays prepared in each example and comparative example were applied to a glass substrate (50 mm x 70 mm) using a spin coater to a film thickness of 3.5 μm. The substrate was prebaked at 100°C for 2 minutes, then exposed to a high-pressure mercury lamp and postbaked at 230°C for 20 minutes, resulting in a black resist pattern formed only in the solid areas. The substrate was cut into 50 mm x 10 mm test pieces. 20 mL of N-methylpyrrolidone (NMP) was placed in a screw bottle and heated to 80°C. The test piece was placed in the screw bottle and placed in an oven at 80°C for 40 minutes. The test piece was then removed from the screw bottle and the eluate was obtained. The absorbance of the eluate was measured using a spectrophotometer (UV-2500PC), and the average absorbance from 300 to 1000 nm was reported as the result. The smaller the value, the better.

[0085] [Table 2]

[0086] As shown in Tables 1 and 2, the pigment dispersion compositions of Preparation Examples 1 to 11 of the present invention and the resist compositions of Examples 1 to 11 using them were able to achieve both excellent solvent resistance and breakpoint. Furthermore, the resist compositions achieved high OD values. Furthermore, the resulting resist films had excellent development adhesion.

Claims

1. A black pigment dispersion composition for displays, comprising lactam black, a polymeric pigment dispersant which is a random copolymer having nitrogen atoms, a first alkali-soluble resin, and a solvent.

2. The black pigment dispersion composition for displays according to claim 1, further comprising a sulfonic acid group-containing pigment dispersing aid.

3. 3. A black pigment dispersion composition for displays according to claim 1, a second alkali-soluble resin, a photopolymerizable compound, and a photopolymerization initiator, The second alkali-soluble resin comprises an alkali-soluble resin having a crosslinking functional group.

4. A black resist film formed from the black pigment dispersed resist composition for displays according to claim 3.

Images