Black pigment dispersion and photosensitive coloring composition

Abstract

[Problem] To provide a pigment dispersion composition that exhibits high resistance and has excellent dispersion stability and plate-making properties. [Solution] A pigment dispersion composition containing at least carbon black, a pigment dispersant, and an alkali-soluble resin, the pigment dispersion composition being characterized in that the acid value of the alkali-soluble resin is 0-50 mg KOH / g.

Description

Black pigment dispersion and photosensitive coloring composition

[0001] The present invention relates to a black pigment dispersion and a photosensitive coloring composition containing carbon black, which have dispersion stability, plate-making properties, and high resistance.

[0002] Color filters used in liquid crystal display devices and solid-state imaging devices are manufactured by patterning a black matrix and the three primary colors of light, RGB, in stripes or the like on a glass or plastic transparent electrode substrate using photolithography. In photolithography, a photosensitive coloring composition, which is generally made by dissolving or dispersing a dye or pigment as a coloring material in a solvent and blending it with a photosensitive resin component or the like, is applied to a glass substrate, silicon substrate, or the like, and then goes through processes such as exposure / curing, development, and thermal curing to manufacture the color filters.

[0003] Black matrices are used in liquid crystal display devices to prevent light leakage from between drive electrodes. They are typically formed by applying a photosensitive coloring composition, in which a black colorant is dispersed in a solvent, to a substrate, curing the composition by irradiating it with light, and then cleaning the blank areas with an alkaline developer. Alkali-soluble resins are often added to photosensitive coloring compositions for use as binders or the like. In recent years, displays have become increasingly high-resolution and bright, and the line widths of black matrices are on the order of several micrometers. To achieve adhesion that allows such fine patterns to be maintained even after alkaline development, photosensitive coloring compositions using resins such as cardo resins and epoxy acrylate resins having a bisphenol fluorene structure with adjusted amounts of carboxylic acid groups and polymerizable unsaturated groups as alkali-soluble resins, as well as pigment dispersion compositions that can be used to prepare photosensitive coloring compositions, have been proposed (Patent Documents 3, 4, and 5).

[0004] Furthermore, as a coloring material used in photosensitive coloring compositions, carbon black, which has a particularly high optical density, is often used as a black pigment to prevent light leakage. However, carbon black has low electrical resistance and can cause malfunctions. Therefore, a method has been adopted in which carbon black particles are prevented from contacting each other, thereby inhibiting conductivity and increasing resistance. For example, a method using resin-coated carbon black, in which carbon black is coated with a resin (Patent Document 1), and a method using grafted carbon black, in which functional groups are bonded to the surface of carbon black (Patent Document 2), have been mainly used.

[0005] JP 2001-152047 WO2013 / 129555 JP 2022-108724 JP 2019-35958 JP 2010-15158

[0006] However, these conventional methods for increasing resistance are expensive, and other methods for increasing resistance are required. Furthermore, the inventors' investigations have revealed that, among these conventional methods, the use of epoxy acrylate resins provides good developability but does not increase resistance. Furthermore, the use of epoxy resins has been found to increase resistance but deteriorate developability. Therefore, a photosensitive coloring composition that has both high resistance and excellent developability is required.

[0007] Therefore, the present inventors have conducted extensive research and have found that by adding a compound having a specific skeleton and acid value to a carbon black dispersion, it is possible to obtain a black pigment dispersion and a photosensitive coloring composition that can produce a black matrix exhibiting high resistance, and have thereby completed the present invention.

[0008] That is, the present invention provides: (1) a black pigment dispersion in which carbon black is dispersed in a dispersion medium, the black pigment dispersion comprising a biphenyl novolac compound having a biphenyl novolac skeleton and an acid value of 0 to 50 g / mol or less; (2) the black pigment dispersion according to (1) above, wherein the biphenyl novolac compound has a weight average molecular weight of 6,000 to 10,000; (3) the black pigment dispersion according to (1) above, wherein the biphenyl novolac compound is represented by the following formula: wherein m represents an integer of 1 to 8, and n represents an integer of 9 to 22. (4) A black pigment dispersion according to (1) above, characterized in that the mass fraction of the biphenyl novolac compound relative to the total solid content of the black pigment dispersion is 5 to 30 mass% in terms of solid content, (5) A black pigment dispersion according to (1) above, wherein the carbon black is acidic carbon black, (6) A method for producing a photosensitive coloring composition, characterized in that the black pigment dispersion according to (1) above is blended with at least a photopolymerization initiator and a polymerizable monomer, (7) A photosensitive coloring composition according to (6) above, characterized in that it is used for a black matrix, and (8) A photosensitive coloring composition containing at least the following components: (i) carbon black, (ii) a biphenyl novolac compound having a biphenyl novolac skeleton and an acid value of 0 to 50 g / mol or less, (iii) a photopolymerization initiator, (iv) a polymerizable monomer, and (v) an organic solvent.

[0009] The present invention can provide a black pigment dispersion and a photosensitive coloring composition that can produce a black matrix exhibiting high resistance. The black pigment dispersion and the photosensitive coloring composition of the present invention also have excellent dispersion stability and plate-making properties.

[0010] The present invention will be described in detail below.

[0011] (Carbon Black) The carbon black used in the present invention is not particularly limited. Carbon black conventionally used for black matrices can be appropriately selected and used. Examples of carbon black include neutral carbon black and acidic carbon black as follows.

[0012] Examples of neutral carbon black include Printex 25, Printex 35, and Printex 45 manufactured by Orion Engineered Carbons, and #85 and #95 manufactured by Mitsubishi Chemical Corporation.

[0013] Examples of acidic carbon black include SpecialBlack 250, SpecialBlack 350, SpecialBlack 4, SpecialBlack 5, SpecialBlack 6, NEROX 2500, NEROX 3500, and NEROX 305 manufactured by Orion Engineered Carbons, MA-8, MA-11, MA-77, MA-100, and MA-285 manufactured by Mitsubishi Chemical Corporation, and Raven 1060 and Raven 1080 manufactured by Columbia Chemicals. Acidic carbon black is preferred from the viewpoint of imparting resistivity. Furthermore, from the viewpoints of light-shielding properties, storage stability, and plate-making properties, the average primary particle diameter is preferably 20 to 60 nm, and more preferably 25 to 40 nm. The primary particle size can be determined by image analysis of electron microscope images, but for commercially available carbon black, the value in the manufacturer's catalog may also be used. The DBP oil absorption (K 6217-4:2017) of the carbon black is preferably 10 to 150 ml / 100 g, and more preferably 30 to 100 ml / 100 g.

[0014] (Biphenyl novolac compound) The present invention is characterized in that the black pigment dispersion contains a specific biphenyl novolac compound, which will be described below. That is, it is a biphenyl novolac compound having an acid value of 0 to 50 g / mol. Here, the biphenyl novolac compound is a compound having a portion in which biphenyl rings and novolac structures are alternately linked. For example, it can be represented by the following chemical formula (I): Chemical formula (I)

[0015] R, R', and R'' are organic groups which may be the same or different. It is known that the solubility in an alkaline developer and the curing by UV irradiation can be controlled by adjusting the type and amount of this organic group. For example, a compound represented by the following chemical formula (II) is known, and it has been conventionally known that it exhibits heat resistance due to the biphenyl novolac skeleton, is soluble in an alkaline developer due to the carboxy group, and is cured by UV irradiation due to the vinyl polymerizable double bond. In other words, the biphenyl novolac compound contained in the present invention can also function as an alkali-soluble resin, but the present inventors have surprisingly found that by adjusting the acid value of the biphenyl novolac compound to a certain amount or less, it is possible to obtain a black pigment dispersion and a photosensitive coloring composition which are excellent in dispersion stability and plate-making properties and which can form a black matrix having a high resistance value.

[0016] Chemical formula (II) In chemical formula (I) and chemical formula (II), m represents an integer of 1 to 8, and n represents an integer of 9 to 22. m is preferably an integer of 3 to 8, particularly preferably 4 to 8, and n is preferably an integer of 12 to 22, particularly preferably 15 to 22.

[0017] The mechanism is not entirely clear, and while conventional knowledge has suggested that a certain amount of carboxyl groups is necessary for alkali solubility, we have surprisingly found that a reduced amount of this moiety can achieve excellent dispersion stability, platemaking properties, and high resistance. Specifically, one of the features of the present invention is that the acid value of the biphenyl novolac compound is 0 to 50 mgKOH / g. An acid value of 0, or even no acid value, is acceptable. It has been found that an acid value exceeding 50 mgKOH / g does not provide sufficient resistance. A value of 45 mgKOH / g or less is preferable, and 40 mgKOH / g or less is particularly preferable. Within this range, particularly high resistance can be achieved. The acid value can be calculated from the molecular weight, charge ratio, and degree of polymerization of the raw material monomers. If these values ​​are unknown, they can be determined in accordance with JIS K5601-2-1:1999.

[0018] This compound does not need to be added during the preparation of the black pigment dispersion; after the black pigment dispersion is prepared, it can be added simultaneously with or separately from other components of the photosensitive composition (described below), either before or after the other components. However, because this compound also has pigment dispersing properties, adding it during dispersion preparation can reduce the amount of pigment dispersant (described below), thereby improving developability. Furthermore, adding it during the preparation of the black pigment dispersion is expected to improve compatibility with carbon black and enhance performance. The weight-average molecular weight of the biphenyl novolac compound is particularly preferably 6,000 to 10,000, more preferably 7,000 to 9,000, and most preferably 7,500 to 8,500. Here, the weight-average molecular weight can be calculated from the molecular weights of the raw monomers, their charge ratios, and the degree of polymerization. If these are unknown, it can be measured using GPC. For specific conditions, known methods used for compounds of similar structure and molecular weight can be used. Within this range, the effects described above are particularly pronounced. If the molecular weight is too high, developer solubility decreases, while if the molecular weight is too low, dispersion stability and resistance may decrease. This is presumably because steric hindrance is no longer sufficient.

[0019] The content of the biphenyl novolac compound, expressed as a mass fraction relative to the total solids content of the black pigment dispersion, is preferably 5 to 30 mass% converted to solids, more preferably 5 to 25 mass%, and most preferably 8 to 20 mass%. Excellent dispersibility and viscosity characteristics are achieved within this range. If the content is too low, dispersibility may decrease, while if it is too high, viscosity tends to increase. Examples of such biphenyl novolac compounds include the ZCR series and CCR series from Nippon Kayaku Co., Ltd.

[0020] (Dispersion Medium) The black pigment dispersion of the present invention contains at least the carbon black and the specific biphenyl novolak compound described above in a dispersion medium. The dispersion medium is not limited, but an organic solvent is generally preferred. Suitable organic solvents include those conventionally used in the fields of liquid crystal black matrix resists and pigment dispersions used in their preparation.

[0021] Specific examples include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 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, diethylene glycol methyl ethyl ether, etc. These can be used alone or in combination of two or more.

[0022] (Dispersant) In the present invention, it is preferable to contain a pigment dispersant in the black pigment dispersion. A basic group-containing dispersant is preferred, and representative examples include anionic surfactants, polyester dispersants, acrylic dispersants, and urethane dispersants. These basic group-containing dispersants may be used alone or in combination of two or more. Among these, polymeric pigment dispersants are preferred because they provide good dispersibility.

[0023] Examples of polymeric dispersants include the DISPERBYK series manufactured by BYK Chemie, the EFKA series manufactured by BASF, the DISPARLON series manufactured by Kusumoto Chemicals, the SOLSPERSE series manufactured by Lubrizol, and the AJISPER series manufactured by Ajinomoto Fine-Techno Co., Ltd. The amount of dispersant blended is preferably 5 to 50 parts by weight, more preferably 5 to 35 parts by weight, and even more preferably 10 to 20 parts by weight, per 100 parts by weight of carbon black. As mentioned above, the specific biphenyl novolac compound used in the present invention also has pigment dispersing properties, so carbon black can be sufficiently dispersed even with a relatively small amount of dispersant blended. This results in excellent plate-making properties for the resulting photosensitive coloring composition. Note that plate-making properties refer to the high performance of a negative resist, such as low residue and high linearity after alkaline development, when the photosensitive coloring composition is used as a negative resist. This performance is also referred to as developability.

[0024] (Dispersing Aid) If necessary, compounds such as known pigment derivatives may be added. These compounds act as an intermediary between the pigment and the dispersant, and are thought to have the function of improving dispersion stability by adsorbing physically, electrically, and chemically to the pigment surface and the dispersant.

[0025] Examples of pigment derivatives include those based on organic pigments such as diketopyrrolopyrroles, anthraquinones, phthalocyanines, quinacridones, azochelates, azo compounds, isoindolinones, pyranthrones, indanthrones, anthrapyrimidines, dibromoanthanthrones, flavanthrones, perylenes, perinones, quinophthalones, thioindigo compounds, and dioxazines, and which incorporate substituents such as hydroxyl groups, carboxyl groups, sulfonic acid groups, carbonamido groups, and sulfonamido groups. These pigment derivatives and other compounds can be used alone or in combination. Among these, phthalocyanine pigment derivatives containing sulfonic acid groups are preferred from the perspective of carbon black dispersibility. The amount of dispersing aid added is preferably 1 to 10 parts by weight, more preferably 1 to 5 parts by weight, and even more preferably 1 to 3 parts by weight, per 100 parts by weight of carbon black.

[0026] (Production of Black Pigment Dispersion) The black pigment dispersion of the present invention can be obtained by mixing and kneading the above components. The kneading method is not particularly limited, and can be carried out using, for example, a paint shaker, a bead mill, a sand mill, a ball mill, or the like. Typically, the dispersed particle size is preferably 80 to 300 nm (cumulant diameter by cumulant analysis). The dispersed particle size can be measured using various known methods and devices such as dynamic light scattering.

[0027] The black pigment dispersion of the present invention can be obtained in this manner. The black pigment dispersion of the present invention exhibits dispersion stability, plate-making properties, and high resistance. The viscosity remains almost unchanged even after 7 days at 40°C. If the viscosity immediately after preparation of the dispersion is taken as 100%, the value after 7 days at 40°C can be 120% or less, 110% or less, or even 105% or less, demonstrating its excellent stability. Furthermore, the dispersion exhibits excellent plate-making properties, and when used as a photosensitive coloring composition, it leaves little residue and exhibits high linearity. When a photosensitive coloring composition is prepared using this dispersion and used as a negative resist, the resulting coating exhibits high resistance. Specifically, when tested using the following method, the resistance can be 4.5E+10 (Ω / □) or more, and even 2.7E+11 (Ω / □) or more. The photosensitive coloring composition was applied to a glass substrate using a spin coater to a film thickness of 1 μm, prebaked at 80°C for 10 minutes, and then a photomask was placed on top. The composition was then exposed to 30 mJ / cm using an ultraviolet fiber spot irradiation device. 2 The black matrix coating film is then exposed to ultraviolet light of 1000 W at 230°C for 60 minutes, and then post-baked to produce a black matrix coating film. The surface resistance of the produced black matrix coating film is measured using, for example, a "Hiresta-UP MCP-HT450" manufactured by Mitsubishi Chemical Corporation.

[0028] (Photosensitive Coloring Composition) The photosensitive coloring composition of the present invention can be obtained by adding additional components necessary for the photosensitive coloring composition to the black pigment dispersion liquid described above. The photosensitive coloring composition of the present invention can be obtained by mixing at least a photopolymerization initiator and a polymerizable monomer as necessary components. The photosensitive coloring composition of the present invention contains at least the following components: (i) carbon black; (ii) a biphenyl novolac compound having a biphenyl novolac skeleton and an acid value of 0 to 50 g / mol; (iii) a photopolymerization initiator; (iv) a polymerizable monomer; and (v) an organic solvent. While it is sufficient to contain these components, it is highly desirable to obtain the photosensitive coloring composition of the present invention by adding additional components necessary for the photosensitive coloring composition to the black pigment dispersion liquid described above. This is because high performance can be achieved by thoroughly dispersing the black pigment carbon black to achieve a well-dispersed state and then blending the photopolymerization initiator and polymerizable monomer. The other components of the photosensitive coloring composition are described below.

[0029] 1. Photopolymerization Initiator Any known photopolymerization initiator can be used without limitation. Examples include aromatic ketones, lophine dimers, benzoins, benzoin ethers, acetophenones, benzophenones, thioxanthones, ketals, quinones, triazines, imidazoles, oxime esters, phosphines, borates, carbazoles, titanocenes, and polyhalogens. For example, a combination of 4,4'-bis(diethylamino)benzophenone and 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 4-[p-N,N-di(ethoxycarbonylmethyl)-2,6-di(trichloromethyl)-s-triazine], and 2-methyl-4'-(methylthio)-2-morpholinopropiophenone are preferred. These photopolymerization initiators may be used alone, or two or more may be mixed in any ratio as needed.

[0030] 2. Polymerizable Monomers Polymerizable monomers are so-called photopolymerizable monomers that are commonly incorporated into photosensitive coloring compositions. They are components that polymerize and harden upon UV irradiation. In the present invention, known monomers can be used without limitation. Examples include monofunctional monomers such as nonylphenyl carbitol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-ethylhexyl carbitol acrylate, 2-hydroxyethyl acrylate, and N-vinylpyrrolidone; bifunctional monomers such as tripropylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, and bisphenol A diacrylate; trifunctional monomers such as trimethylolpropane triacrylate and pentaerythritol triacrylate; and other polyfunctional monomers such as dipentaerythritol pentaacrylate and hexaacrylate. Two or more of these photopolymerizable monomers can also be used.

[0031] 3. Alkali-Soluble Resin Furthermore, alkali-soluble resins commonly used in negative resists can be blended. Alkali-soluble resins refer to components that are soluble in alkaline developers but become insoluble in the alkaline developer upon UV irradiation, and include compounds with a weight-average molecular weight of approximately 3,000 to 15,000. The specific biphenyl novolac compound mentioned above also becomes insoluble in alkaline developers upon UV irradiation, so this compound can also be used. Various other known alkali-soluble resins can be used without any particular limitation. Examples of known alkali-soluble resins include those that are soluble in alkaline aqueous solutions. For example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl (meth)acrylate, Examples of alkali-soluble resins include copolymers of one or more selected from the group consisting of (meth)acrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, vinylacetic acid, and anhydrides thereof, and copolymers of the above-mentioned copolymers with an ethylenically unsaturated compound having a glycidyl group or a hydroxyl group. These alkali-soluble resins can also be added when the black pigment dispersion liquid described above is prepared.

[0032] The photosensitive coloring composition of the present invention can be obtained by mixing the above components. The blending amount of each of these components is 0.1 to 20 mass% of the photopolymerization initiator, preferably 0.5 to 15 mass%, more preferably 1 to 15 mass% of the total solid content of the photosensitive coloring composition, 15 to 30 mass% of the polymerizable monomer, preferably 17.5 to 27.5 mass%, more preferably 19.5 to 25 mass% of the total solid content of the photosensitive coloring composition, and 5 to 85 mass% of the alkali-soluble resin, preferably 10 to 80 mass%, more preferably 15 to 75 mass% of the total solid content of the photosensitive coloring composition.

[0033] [Color Filter] A color filter can be produced by applying the black pigment dispersion of the present invention or a photosensitive coloring composition using the same to a substrate, photocuring, and developing to obtain a coating film. Hereinafter, this process is referred to as the pre-baking process. The photosensitive coloring composition is preferably applied to a glass substrate or a silicon substrate using a roll coater, slit coater, spray, bar coater, applicator, spin coater, dip coater, inkjet, or screen printing. After application, the organic solvent is preferably dried, and the coating film is preferably heated from the viewpoint of smoothness and ease of handling. The heating temperature is preferably 50 to 140°C, more preferably 70 to 90°C. The heating time is preferably 0.5 to 60 minutes, more preferably 1 to 10 minutes. Photocuring is performed by irradiating the coating film with ultraviolet light to harden it. Photocuring is performed to leave a pattern on the glass substrate in the subsequent development. It is preferable to place a photomask that blocks ultraviolet light on the areas to be removed by development to prevent curing. Photocuring is preferably carried out up to an ultraviolet irradiation dose of 10 to 100 mJ / cm2. Development involves immersing the photocured cured coating film in an alkaline aqueous solution, followed by rinsing with water to remove uncured portions. The alkaline aqueous solution used preferably has an alkaline agent concentration of 0.001 to 10 wt%, more preferably 0.01 to 1 wt%. Furthermore, the alkaline agent used for development is preferably an aqueous solution of ammonia, sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate, triethylamine, triethanolamine, tetramethylammonium hydroxide, or the like.

[0034] The developed coating film is heated to 200 to 300°C to obtain a cured film. Hereinafter, this step is referred to as the post-baking step. By heating the developed coating film, a cured film with excellent hardness can be formed. From the viewpoint of obtaining a cured film with excellent hardness and heat resistance, the heating temperature is preferably 200 to 300°C. From the viewpoint of obtaining a cured film with excellent hardness and heat resistance, the heating time is preferably 10 to 300 minutes. Prior to the post-baking step, pre-heating at 80 to 100°C for 10 to 60 minutes may be performed. The photosensitive coloring composition of the present invention can obtain high resistance while maintaining substrate adhesion and developability without requiring costly treatments such as coating or grafting carbon black with a resin.

[0035] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In addition, parts and % represent parts by weight and % by weight.

[0036] The various materials used in the following examples and comparative examples are as follows: (Carbon black) NEROX3500 (manufactured by Orion Engineered Carbons) (Pigment dispersant) DISPERBYK-167 (manufactured by BYK Chemie) (Dispersing aid) Solsperse 5000S (manufactured by Lubrizol Corporation) (Biphenyl novolak compounds) KAYARAD ZCR-1805H (manufactured by Nippon Kayaku Co., Ltd.) Acid value 20 Mw 8000 KAYARAD ZCR-1806H (manufactured by Nippon Kayaku Co., Ltd.) Acid value 40 Mw 8000 KAYARAD ZCR-1569H (manufactured by Nippon Kayaku Co., Ltd.) Acid value 98 Mw 4500 KAYARAD ZCR-1797H (manufactured by Nippon Kayaku Co., Ltd.) Acid value 98 Mw 6500 KAYARAD These biphenyl novolak compounds are all compounds represented by chemical formula (I), and have different acid values ​​and Mw (weight average molecular weight) due to the different values ​​of m and n.

[0037] Examples 1 to 3 and Comparative Examples 1 to 4 <Preparation of Black Pigment Dispersion> A container was charged with 25 parts by mass of NEROX 3500 carbon black, 3 parts by mass (solids equivalent) of DISPERBYK-167 (52% solids content) as a dispersant, 3 parts by mass (solids equivalent) of each biphenyl novolac compound listed in Table 1, 0.6 parts by mass of Solsperse 5000S as a dispersing aid, and PGMEA. The amount of PGMEA was adjusted so that the total weight of "carbon black + dispersant + biphenyl novolac compound + dispersing aid + PGMEA" was 100 parts by mass. 230 parts by mass of Saint-Gobain ER120 beads (φ0.4 to 0.6 mm) were then charged into the container, and dispersion was carried out for 6 hours using a paint shaker manufactured by Asada Iron Works, to obtain a black pigment dispersion (Table 1).

[0038]

[0039] <Preparation of Photosensitive Coloring Composition> 36 parts of the black pigment dispersion prepared above, 14.20 parts of alkali-soluble resin ("WR-301" manufactured by ADEKA Corporation), 3.65 parts of dipentaerythritol hexaacrylate as a polymerizable monomer, 0.54 parts of ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(0-acetyloxime) (IRGACURE OXE-02) as a photopolymerization initiator, and 45.61 parts of PGMEA as a solvent were added to a container, and the mixture was stirred and mixed to obtain a photosensitive coloring composition.

[0040] (Surface Resistance) The obtained photosensitive coloring composition was applied to a glass substrate using a spin coater to a film thickness of 1 μm, and prebaked at 80° C. for 10 minutes. After that, a photomask was placed on the substrate, and the surface was irradiated with 30 mJ / cm 2 using an ultraviolet fiber spot irradiation device. 2 The black matrix coating film was then subjected to post-baking at 230°C for 60 minutes to produce a black matrix coating film. The surface resistance of the produced black matrix coating film was measured using a "Hiresta-UP MCP-HT450" manufactured by Mitsubishi Chemical Corporation.

[0041] (OD) The optical density (OD) per 1 μm of film thickness of the above black matrix coating was calculated using a "T-5 Plus" manufactured by Ihara Electronics Co., Ltd. (Storage Stability) The viscosity of the black pigment dispersion prepared above was measured using a RE-215L viscometer (25°C, 50 rpm) manufactured by Toki Sangyo Co., Ltd. The results are shown in Table 2 (initial viscosity). The viscosity was then measured again using the same method after one week at 40°C. The viscosity at this time was reported as a percentage of the initial viscosity, which was taken as 100%.

[0042] Pigment dispersions were prepared in the same manner as in Examples 1 to 3 and Comparative Examples 1 to 4, except that commercially available epoxy resins "TECHMORE VG3101L" (manufactured by Printec Co., Ltd.), "NC-3000-H" (manufactured by Nippon Kayaku Co., Ltd.), and "jer1032H60" (manufactured by Mitsubishi Chemical Corporation) were used instead of the biphenyl novolac compound. Photosensitive coloring compositions were prepared in the same manner as in Examples 1 to 3 and Comparative Examples 1 to 4. The developability was evaluated by the following method using the photosensitive coloring compositions prepared in Examples 1 to 3 and Comparative Examples 1 to 4 and photosensitive resin compositions using these epoxy resins. The results obtained are shown in Table 3. (Developability) The photosensitive coloring composition was applied to a glass substrate using a spin coater to a film thickness of 1 μm, prebaked at 80° C. for 3 minutes, and then imagewise exposed to light using a high-pressure mercury lamp through a negative mask with a linear pattern of 10 μm openings (exposure amount 50 mJ / cm). ２ The distance between the sample and the mask was 100 μm. The sample was then developed at 25°C by spraying a developer containing 4% KOH by weight and a nonionic surfactant (NK-disperse HA, manufactured by Nippon Kayaku Co., Ltd., surfactant concentration 8.9% by weight), diluted with water to a KOH concentration of 0.04% by weight. The development time was 1.5 times the dissolution time of the unexposed area. The sample was then heated at 230°C for 1 hour to harden the linear pattern, and the line width of the 10 μm pattern was measured.

[0043] Comparative Examples 1 to 4, which used biphenyl novolac compounds with acid values ​​exceeding 50 mgKOH / g, had resistances in the 10^8 to 10^10 range, lower than those using the biphenyl novolac compounds of the present invention. In other words, the resistance did not increase. On the other hand, the commercially available epoxy resins produced linear patterns with 10 μm openings with line widths in the 13 μm to 15 μm range, which is narrower than the 16 μm range achieved using the compounds of the present invention. This is thought to be due to poor sensitivity to light exposure, which resulted in insufficient curing and dissolution in alkaline developer.

[0044] In contrast, the black pigment dispersions of Examples 1 to 3, which use biphenyl novolac compounds with acid values ​​of 0 to 50 mgKOH / g, show a change in viscosity of 5% or less over time and are excellent in storage stability. Photosensitive colored compositions were prepared using these black pigment dispersions, and the black matrix coating films prepared using these compositions all had a surface resistance of 4.5 × 10 10 It is clear that the surface resistance is high at (Ω / □) or more, and the line width of the linear pattern with 10 μm openings is in the 16 μm range, indicating high sensitivity to exposure and excellent developability.

[0045] The black pigment dispersion and photosensitive coloring composition of the present invention are useful in technologies such as displays.

Claims

1. A black pigment dispersion in which carbon black is dispersed in a dispersion medium, characterized in that it contains a biphenyl novolac compound having a biphenyl novolac skeleton and an acid value of 0 to 50 g / mol.

2. The black pigment dispersion according to claim 1, wherein the weight-average molecular weight of the biphenyl novolac compound is 6,000 to 10,000.

3. The black pigment dispersion according to claim 1, wherein the biphenyl novolak compound is represented by the following formula: Here, m is an integer of 1 to 8, and n is an integer of 9 to 22.

4. The black pigment dispersion according to claim 1, characterized in that the mass fraction of the biphenyl novolac compound relative to the total solid content of the black pigment dispersion is 5 to 30 mass % in terms of solid content.

5. The black pigment dispersion according to claim 1, wherein the carbon black is acidic carbon black.

6. A method for producing a photosensitive coloring composition, comprising blending the black pigment dispersion according to claim 1 with at least a photopolymerization initiator and a polymerizable monomer.

7. The photosensitive coloring composition according to claim 6, which is for use in a black matrix.

8. A photosensitive coloring composition containing at least the following components: (i) carbon black; (ii) a biphenyl novolac compound having a biphenyl novolac skeleton and an acid value of 0 to 50 g / mol; (iii) a photopolymerization initiator; (iv) a polymerizable monomer; and (v) an organic solvent.

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