JP5302097B2 - Ink composition, method for forming colored film using the same, and colored film - Google Patents

Description

  The present invention relates to an ink composition used when a colored film is formed on a substrate provided with a partition wall by an ink jet method, and a colored film obtained using the ink composition.

  There is an increasing demand for color LCDs such as mobile phones, personal computers, thin color televisions, and the like. On the other hand, the price is reduced in line with the increase in demand for large-sized thin color televisions and the like, and there is a high demand for cost reduction for color filters, which are the main components of color LCDs.

  A color filter having a coloring pattern of three primary colors of red (R), green (G) and blue (B) on a substrate has been manufactured by a method represented by a dyeing method or a pigment dispersion method. Among these, the dyeing method is to pattern a transparent water-soluble polymer material on a support substrate such as a glass substrate into a desired shape by photolithography, and then immerse the obtained transparent pattern in an aqueous dye solution to dye the transparent pattern, By repeating this three times, a colored film of R, G and B is formed. In the pigment dispersion method, a photosensitive resin layer in which a pigment is dispersed is formed on a substrate, and a necessary portion is irradiated with ultraviolet rays using a photomask, followed by alkali development to obtain a monochromatic pattern. Is repeated three times to form R, G, and B colored films. As a method other than the dyeing method and the pigment dispersion method, a method in which an ink in which a pigment is dispersed in a thermosetting resin is printed by R, G, and B three times by an offset printing method and then the resin is thermally cured. Etc.

  However, in any of these methods, in order to color the three colors R, G and B, it is necessary to repeat the same process three times. For this reason, there is a problem that the cost increases and the yield decreases. In order to solve these problems, a method for producing a color filter by ejecting ink compositions forming respective colored films at a time by an inkjet method has been proposed, and various studies have been made. In this method for producing a color filter by the ink jet method, in order to prevent the diffusion of the ink composition of three colors, a partition (black matrix) is provided in advance on a support substrate, and a predetermined ink is provided in a space region defined by the partition. A colored film is formed by discharging the composition (see, for example, Patent Document 1).

  By the way, in a color filter, it is necessary to accurately create a fine colored pattern on a support substrate. In the case of an ink jet method, a partition wall is subjected to a liquid repellent treatment in order to prevent mixing of colors of adjacent colored films. In addition, a method has been proposed in which the surface of the support substrate in the space region where the colored film is formed is subjected to lyophilic treatment so that the ink composition is adhered accurately and reliably (see, for example, Patent Document 2). However, due to the ink repellent function of the partition walls, a colored film may not be formed just before the partition walls, which may cause color loss, or a colored film may not be formed flat and may cause color unevenness. Therefore, by making the curable resin used in the ink composition a thermosetting resin having a specific melt index and glass transition point, it is possible to sufficiently level the discharged ink composition during the drying process. Has been proposed (see Patent Document 3).

JP 59-75205 A JP 2001-350012 A JP 2008-15270 A

  However, the level of flatness of the colored film formed by the ink jet method, including the conventionally proposed methods, has not reached a sufficiently satisfactory level. Thus, when the present inventors examined this cause, surprisingly, the fact that one of the factors that hinders the flattening of the colored film is a dent at the top of the colored film that appears when the ink composition is cured. I found out. That is, in the colored film after curing, as shown in FIG. 5C, a dent is formed in almost the center in the plane direction of the area defined by the partition walls 2. As for the mechanism, the inventors of the present invention first guessed that the ink composition ejected into the space area defined by the partition walls 2 formed on the support substrate 1 has a solvent from its surface in the drying process and the curing process. It evaporates (arrow line in FIG. 5 (a)). The evaporation of the solvent has a higher evaporation rate at the peripheral portion than at the central portion. Along with this, convection of the ink composition from the central portion toward the peripheral portion occurs (thick arrow line in FIG. 5 (b)). It is considered that a colored film having a raised peripheral edge compared to the central portion is formed, and a dent is generated in the central portion.

  Therefore, as a result of earnestly examining the means for obtaining a flatter colored film without dents, the present inventors made a curable resin directly related to the curing of the colored film into a liquid curable resin at a predetermined ratio, By prescribing the total amount of the liquid curable resin and the solvent, the convection of the ink composition from the central portion to the peripheral portion as described above can be prevented as much as possible, and coloring with excellent flatness The inventors found that a film was obtained and completed the present invention.

  Accordingly, an object of the present invention is to provide an ink composition capable of obtaining a colored film having excellent flatness after curing when the colored film is formed by an ink jet method.

  Another object of the present invention is to provide a colored film having excellent flatness and capable of reducing problems such as color unevenness and color loss as much as possible when a color filter or the like is used.

That is, in the present invention, a colored film is formed by an inkjet method on a support substrate including at least a curable resin (A), a pigment (B), and a solvent (C) and having a plurality of space regions partitioned by partition walls. An ink composition used in the above, wherein the component (A) is at least one self-curable polyfunctional liquid curable resin selected from the group consisting of a liquid epoxy resin and a liquid melamine resin, and has two or more functional groups. In addition, the polyfunctional liquid curable resin (A1) having a viscosity at 25 ° C. of 6000 mPa · s or less is contained in an amount of 60% by weight or more, and the component (C) has a high boiling point solvent (C1 ) Is contained in an amount of 80% by weight or more, and the sum of the components (A1) and (C1) with respect to the total amount ((A) + (B) + (C)] of the components (A) to (C) [(A1) + ( C1)] [[(A1) + (C1)] / [(A) + (B) + (C)]] is 40% by weight or more. An ink composition characterized.

The present invention also provides a colored film obtained by applying the ink composition to a support substrate by an ink jet method, drying and curing the ink composition. Furthermore, the present invention is a method for forming a colored film, wherein the colored film is formed using the ink composition described above with a contact angle with respect to a partition wall of 30 ° or more .

  The ink composition of the present invention is a polyfunctional liquid curable resin (B) having a bifunctional or higher functionality as the curable resin (A) and having a viscosity at 25 ° C. of 12000 mPa · s or less, preferably 6000 mPa · s or less. Contains A1). If the viscosity at 25 ° C. of the polyfunctional liquid curable resin (A1) exceeds 12000 mPa · s, the dent when the colored film targeted by the present invention is cured cannot be reduced, and the colored film after curing is flat. Sex cannot be secured. The content of such a polyfunctional liquid curable resin (A1) is 25% by weight or more, preferably 35 to 95% by weight in the curable resin (A). When the ratio of (A1) in the component (A) is less than 25% by weight, dents during curing of the colored film cannot be reduced, and flatness of the colored film after curing cannot be ensured. .

  The polyfunctional liquid curable resin (A1) needs to be a polyfunctional liquid curable resin having two or more functions in order to satisfy physical properties required for a color filter, such as heat resistance, hot water resistance, and chemical resistance. In particular, polyfunctional liquid curable resins such as acrylic resins, epoxy resins, and melamine resins can be suitably used. In addition, as a liquid cured resin, generally, the lower the molecular weight and the non-crystalline molecular structure, the more liquid and the lower the viscosity.

  Examples of the polyfunctional liquid acrylic resin include diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol (meth) acrylate, and 1,3-butanediol. Di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol dimethacrylate, ethoxylated bisphenol A di (meth) acrylate, propoxylated neopentyl Glycol di (meth) acrylate, tripropylene glycol diacrylate, ethoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, propylene Xylated trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane trimethacrylate pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hydroxypenta A liquid resin composed of (meth) acrylic acid such as acrylate can be exemplified. These may be used alone or in combination of two or more.

  It is desirable to use a polyfunctional liquid acrylic resin that has a self-curing property. However, if the self-curing property is poor or in order to further accelerate the curing, a separate catalyst or curing accelerator is added to the ink composition. You may make it do. Examples of such a catalyst or curing accelerator include acetophenones such as acetophenone and p-tert-butylacetophenone, benzophenones such as benzophenone, 2-chlorobenzophenone, p, p'-bis (dimethylamino) benzophenone, and benzoin. Benzoin ethers such as methyl ether, benzoin isopropyl ether, benzoin butyl ether, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1 Α-aminoalkylphenones such as-(4-morpholinophenyl) -butanone-1, bisacylphosphine oxides such as bis (2,4,6-trimethylbenzoyl) -phenyl-phosphine oxide, N- Glycines such as phenylglycine, 2,4-trichloromethyl- (piperonyl) -6-triazine, 2,4-trichloromethyl- ( And triazines such as 4′-methoxystyryl) -6-triazine. These may be used alone or in combination of two or more. These can also be used in combination with known photopolymerization accelerators (sensitizers) such as p-dimethylaminobenzoic acid isoamyl ester and p-dimethylaminobenzoic acid ethyl ester. In the present invention, when the blending ratio of the component (A) or the component (A1) is specified, these catalysts and curing accelerators are not included in the component (A) or the component (A1).

  Moreover, as a polyfunctional liquid epoxy resin, it consists of an epoxy compound which has two or more epoxy groups in one molecule, for example, novolak type epoxy resin type such as phenol novolak type epoxy and cresol novolak type epoxy, bisphenol A type epoxy type Typical examples include bis-type epoxy resin systems such as bisphenol F-type epoxy, biphenyl-type epoxy resin systems, and alicyclic epoxy resin systems. These may be used alone or in combination of two or more.

  As for the polyfunctional liquid epoxy resin, it is desirable to use a self-curing resin. However, when the self-curing property is poor or to further accelerate the curing, a curing agent or a catalyst is added to the ink composition. You may do it. Examples of such a curing agent include acids and acid anhydrides. Specifically, phthalic anhydride, itaconic anhydride, succinic anhydride, citraconic anhydride, dodecenyl succinic anhydride, tricarballylic anhydride, maleic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, dimethyltetrahydrophthalic anhydride Acid, hymic anhydride, nadic anhydride, 1,2,3,4-butanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, pyromellitic anhydride, trimellitic anhydride, benzophenone tetracarboxylic anhydride , Ethylene glycol bis trimellitate, glycerine tristrimate, succinic acid, glutaric acid, adipic acid, butanetetracarboxylic acid, maleic acid, itaconic acid, hexahydrophthalic acid, 1,2-cyclohexanedicarboxylic acid, 1,2, 4-cyclohexanetrica Typical examples include boronic acid, cyclopentanetetracarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, trimellitic acid, 1,4,5,8-naphthalenetetracarboxylic acid, benzophenonetetracarboxylic acid, etc. Can be mentioned. As the catalyst, tertiary amines, phosphines, quaternary ammonium salts, and Lewis acids are used. Specific examples include tertiary amines such as triethylamine, triphenylamine, tri-n-butylamine, N, N-dimethylaniline, pyridine, imidazole, N-methylimidazole, 2-methylimidazole, 4-methylimidazole, 1 -Various imidazoles such as benzyl-2-methylimidazole, 1,8-diazabicyclo (5,4,0) undecene-7,1,5-diazabicyclo (4,3,0) nonene-5, 6-dibutylamino- Amidines such as 1,8-diazabicyclo (5,4,0) undecene-7, tertiary amine compounds typified above and adducts thereof with organic acids, etc., amines and halogens, Lewis acids, Quaternary ammonium salts with organic acids, mineral acids, boron tetrafluoride, etc., phosphines such as triethylphosphine, triphenylphosphine, tri-n-butylphosphine, boron trifluoride Lewis acids such as boron trifluoride etherate and the like. These curing agents and catalysts are preferably used to such an extent that the viscosity stability of the ink composition is not impaired, and are desirably liquid.

The polyfunctional liquid melamine resin is represented by the following general formula [wherein R _{1 to} R ₆ are —H, CH ₂ OH, CH ₂ OR ′ (R ′ is an alkyl group having 1 to 4 carbon atoms). R _{1 to} R ₆ may be the same or different], in addition to the complete alkyl group type, imino group type, methylol group type, or mixed melamine resins and oligomers thereof, Guanamine, acetoguanamine, benzoguanamine, ethyldiamino-S-, which has an S-triazine skeleton as in the formula, and in which a part of the substituent -NRR is substituted with an aromatic hydrocarbon or an alkyl group having 1 to 4 carbon atoms Examples include triazine, urea resin, and similar products. Among them, butylated melamine resin, methylated melamine resin, mixed alkylated melamine resin, imino group-containing alkylated melamine resin, methylol group / imino group in which a methylol group is partially or fully alkylated in a condensate of melamine and formaldehyde Group-containing alkylated melamine resins are preferred. These may be used alone or in combination of two or more.

  As for the polyfunctional liquid melamine resin, it is desirable to use a resin having a self-curing property. However, when the self-curing property is poor or in order to further accelerate the curing, a catalyst or a metal soap is separately added to the ink composition. You may do it. Examples of such a catalyst include aromatic sulfonic acid and phosphoric acid. A type excellent in storage stability in which an acidic group is blocked with an amino group or the like can also be used. As metal soaps, zinc stearate, zinc myristate, aluminum stearate, calcium stearate and the like can be used.

  In the ink composition of the present invention, other curable resins may be used in combination as long as the polyfunctional liquid curable resin (A1) in the component (A) does not deviate from the predetermined ratio. The curable resin is preferably a bifunctional or higher polyfunctional curable resin, and specific examples thereof include acrylic resins, epoxy resins, and melamine resins.

  Further, regarding the solvent (C) contained in the ink composition of the present invention, in the component (C), the high boiling point solvent (C1) having a boiling point of 200 ° C. or higher is 80% by weight or more, preferably 90 to 100% by weight. Like that. Coexistence of a solvent having a boiling point of less than 200 ° C. may be preferable in reducing dry tact, but if the solvent having a boiling point of less than 200 ° C. exceeds 20% by weight in the component (C), the evaporation of the solvent in the ink composition becomes too fast. As a result, the flatness of the colored film is lowered.

  Although it does not restrict | limit especially about the high boiling point solvent (C1) whose boiling point is 200 degreeC or more, Preferably diethylene glycol monoalkyl ether and its terminal acetate, dipropylene glycol monoalkyl ether and its terminal acetate or diether, diethylene glycol dialkyl ethers , Diethylene glycol monoalkyl ethers and terminal acetates thereof, and at least one selected from the group consisting of polyethylene glycol dialkyl ethers.

  In the present invention, the sum of the components (A1) and (C1) with respect to the total amount ((A) + (B) + (C)] of the components (A) to (C) [(A1) + (C1) ] [[(A1) + (C1)] / [(A) + (B) + (C)]] is 40% by weight or more, preferably 50% by weight or more. The total of the polyfunctional liquid curable resin (A1) having a viscosity of 12000 mPa · s or less and the high-boiling solvent (C1) having a boiling point of 200 ° C. or higher is calculated based on the total amount of the components (A) to (C) in the ink composition. When the ink composition ejected into the space region formed by the partition walls is cured, the convection in the ink composition that forms the dent as described in FIG. I found that I can prevent it.

  For the pigment (B) contained in the ink composition of the present invention, either an organic pigment or an inorganic pigment may be selected. Among these, organic pigments include, for example, azo lake, insoluble azo (PY150), phthalocyanine (PG7, PG36 & PB15.6) cyanine, quinophthalone (PY138), quinacdrine, dioxazine (PV23), isoindo. Examples thereof include pigments such as linone (PY139), belinone, anthraquinone (PR177), pyrrolopyrrole (PR254), and perylene, and one or more of these may be used in combination. Examples of the inorganic pigment include miloli blue, iron oxide, cobalt-based, manganese-based, ultramarine blue, bitumen, cobalt blue, cerulean blue, pyridiane, emerald green, cobalt green, and the like, one or two of these. The above can also be used together. These pigments are preferably dispersed in an average particle diameter of 0.4 μm or less, which is the lower limit of the wavelength of visible light, so that the pigmented film can be colored while maintaining the transparency. For practical purposes, it is more preferable that the average particle diameter range is 100 nm or less.

  The blending ratio of the pigment (B) is the ratio of the component (B) to the sum of the components (A) and (B) [(A) + (B)] [(B) / [(A) + ( B)]] is 20 to 60% by weight, preferably 30 to 50% by weight. When the ratio of the component (B) is less than 20% by weight, it is necessary to increase the thickness of the colored film in order to obtain sufficient coloration. As a result, adjacent ink compositions are mixed through the partition walls, resulting in color mixing. There is a risk of it. On the other hand, when the amount exceeds 60% by weight, the pigment is unevenly distributed at the peripheral portion in the ink composition ejected in the space region formed by the partition wall even when the convection forming the dent as shown in FIG. As a result, the flatness of the colored film may be impaired.

  The pigment (B) may be blended in the ink composition in the form of a pigment dispersion containing a dispersant necessary for finely dispersing and stabilizing the pigment. As the dispersant, ionic or nonionic surfactants can be used. Specific examples include sodium alkylbenzene sulfonate, poly fatty acid salts, fatty acid salt alkyl phosphates, tetraalkyl ammonium salts, polyoxyethylene alkyl ethers, and other organic pigment derivatives and polyesters. One type of dispersant may be used alone, or two or more types of dispersants may be mixed and used as necessary. However, in the present invention, when the composition ratio of the ink composition is specified, the dispersant other than the pigment is not included in the component (B).

  Further, the ink composition in the present invention preferably has a contact angle with respect to the partition wall of 30 ° or more. For example, the partition walls forming the black matrix of the color filter may be treated with fluorine treatment by plasma treatment after the partition formation, or by adding fluorine and silicon components having liquid repellency in the black matrix composition in advance. In general, the ink composition of the present invention should have a contact angle of 30 ° or more with respect to the partition wall subjected to such a liquid repellent treatment. When a colored film such as a color filter is formed using the ink composition of the present invention, the colored film is formed by drying and curing the ink composition applied by an ink jet method, as in a general method. Can be obtained.

  The support substrate on which the colored film is formed using the ink composition of the present invention is not particularly limited as long as it is used when forming a color filter or the like by an inkjet method, but in general, transparency and mechanical properties are not limited. It should be satisfactory in terms of strength and the like. Specifically, in addition to a glass substrate, a plastic sheet or plastic film such as polycarbonate, PET, or polyimide can be used. In addition, for the partition provided in the support substrate, the shape and size of the space area to be partitioned, the material for forming the partition, etc., as long as it is suitable for the purpose of forming a colored film by an ink jet method including a color filter There are no restrictions. Furthermore, as for the ink jet system for applying the ink composition to the support substrate, any ink-jet method may be used as long as it can discharge a predetermined ink composition to each of a plurality of space regions of the support substrate via a nozzle. For example, what is generally used in production of a color filter or the like can be applied, and there are no restrictions on the nozzle diameter, the ink composition ejection method, and the like.

  In the formation of a colored film by an ink jet method using a conventional ink composition, the ink composition applied to the space region formed by the partition wall has a higher evaporation rate of the solvent around the partition wall than the center part. In the ink composition of the present invention, convection of the ink composition occurs toward the peripheral edge, the vicinity of the partition wall is convex, and a colored film having a depression in the center is formed. Since the resin (A1) and the high-boiling solvent (C1) having a boiling point of 200 ° C. or higher are contained in a predetermined range, the solvent can be evaporated while always ensuring uniform fluidity when obtaining a colored film. In this way, by preventing the ink composition from convection toward the peripheral portion and evaporating the solvent, a colored film excellent in flatness can be obtained while maintaining the shape as it is even after the step of curing the curable resin. .

  In addition, when the ink composition of the present invention is used, it is possible to obtain a very good colored film having excellent flatness. Therefore, for example, when a color filter or the like is formed, problems such as color unevenness and color loss are possible. Can be reduced.

FIG. 1 is an explanatory plan view showing a state in which a colored film is formed in a space region defined by partition walls of a support substrate. FIG. 2 shows the height distribution of the colored film made of the ink composition of Example 1 as viewed from the X-X ′ cross-sectional direction and the Y-Y ′ cross-sectional direction of FIG. 1. FIG. 3 shows the height distribution in the case of the ink composition of Reference Example 3 , as in FIG. FIG. 4 shows the height distribution in the case of the ink composition of Comparative Example 1, as in FIG. FIG. 5 is an explanatory cross-sectional view showing a case where a colored film is formed by an inkjet method using a conventional ink composition.

  EXAMPLES Hereinafter, although an Example etc. demonstrate this invention more concretely, this invention is not limited to these. In addition, unless otherwise indicated below, a part represents a weight part and% represents weight%. Moreover, the preparation method of each pigment dispersion containing a pigment is described below.

[Preparation of pigment dispersion 1]
142 g of a pigment PR254 (trade name BT-CF manufactured by Ciba Japan Co., Ltd.) and PY150 (manufactured by LANXESS: YELLOW PIGMENT E4GN) mixed at a weight ratio of 80/20 was collected in a 2 L stainless steel container, 160 g of a dispersant (Ajinomoto Co., Ltd., PB823) made into a 50% solution with butyl carbitol (BC) was added to 20 g of butyl carbitol (BC), and fluidity was obtained with a three roll coated with ceramic coating. Until kneaded. Next, after adding and mixing 278 g of diethylene glycol monobutyl ether acetate (BDGAC), the obtained kneaded material was dispersed by a horizontal sand mill until the average particle size of the pigment became 100 nm or less. After completion of the dispersion, it was diluted with 400 g of diethylene glycol monobutyl ether acetate (BDGAC) to obtain a test pigment dispersion 1 having a solid content of 22.2%.

[Preparation of pigment dispersion 2]
129 g of pigment PG36 (manufactured by Basf Co., Ltd .: Heliogen Green L9361) and PY150 mixed at a weight ratio of 60/40 is collected in a 2 L stainless steel container and 50% solution with diethylene glycol monoethyl ether acetate (EDGAC). 120 g of the dispersant (PB823 manufactured by Ajinomoto Co., Inc.) was added, and this was kneaded with a three roll coated with ceramic coating until fluidity appeared. Next, 159.3 g of diethylene glycol monoethyl ether acetate (EDGAC) was added and mixed, and the obtained kneaded material was dispersed with a horizontal sand mill until the average particle size of the pigment was 100 nm or less. After completion of the dispersion, it was diluted with 440 g of 1,3-BGDA (1,3-butylene glycol diacetate) to obtain a test pigment dispersion 2 having a solid content of 22.5%.

[Preparation of pigment dispersion 3]
129 g of a mixture of pigments PG36 and PY150 at a weight ratio of 60/40 was collected in a 2 L stainless steel container, and a dispersant (PB823 manufactured by Ajinomoto Co., Inc.) made into a 50% solution with propylene glycol monomethyl ether acetate (PGMEA) was collected. 120 g was added and kneaded with a three roll coated with ceramic coating until fluidity appeared. Next, 159.3 g of propylene glycol monomethyl ether acetate (PGMEA) was added and mixed, and the obtained kneaded material was dispersed with a horizontal sand mill until the average particle size of the pigment was 100 nm or less. After completion of the dispersion, it was diluted with 440 g of propylene glycol monomethyl ether acetate (PGMEA) to obtain a test pigment dispersion 3 having a solid content of 22.5%.

[Preparation of pigment dispersion 4]
126 g of pigment PB15.6 (manufactured by Basf: Heliogen Blue L-6700F) was collected in a 2 L stainless steel container, and dispersed in a 50% solution of propylene glycol monomethyl ether acetate (PGMEA) in 108 g of butyl carbitol (BC). 128 g of the agent (PB823 manufactured by Ajinomoto Co., Inc.) was added, and this was kneaded with a three roll coated with ceramic coating until fluidity appeared. To the obtained kneaded product, 226.6 g of propylene glycol monomethyl ether acetate (PGMEA) was further added and mixed, and then dispersed in a horizontal sand mill until the average particle size of the pigment was 100 nm or less. After completion of the dispersion, it was diluted with 412 g of butyl carbitol acetate (BCA) to obtain a test pigment dispersion 4 having a solid content of 18.7%.

<Examples 1, 4, 5, Reference Examples 1 to 3 and Comparative Examples 1 to 5>
First, the solid curable resin (A3), the polyfunctional liquid curable resin (A1), the solvent (C), and the additives (silane coupling agent, surfactant) are prepared in the ratio (g) shown in Table 1. Then, the ink dispersions according to Examples 1, 4, 5, Reference Examples 1 to 3 , and Comparative Examples 1 to 5 were added by adding the pigment dispersions 1 to 4 obtained above in the weights shown in Table 1. Got. The meanings of the abbreviations used in Table 1 are as follows. The viscosity of the liquid curable resin was measured at 25 ° C. using an E-type viscometer (DV-II + Pro CP type manufactured by Brookfield).

[A3-1] Fluorene type epoxy type acrylate / acid anhydride polymerization adduct (manufactured by Nippon Steel Chemical Co., Ltd. V259ME: resin component 56.5% PGMEA solution (viscosity 9000 mPa · s at 25 ° C))
[A3-2] Biphenyl type epoxy resin (Japan Epoxy Resin YX4000HK: Solid)
[A3-3] Phenol novolac epoxy resin (Japan Epoxy Resin 154: Solid)
[A1-1] Mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (manufactured by Nippon Kayaku Co., Ltd. DPHA: liquid (viscosity of 11900 mPa · s at 25 ° C))
[A1-2] Pentaerythritol triacrylate (manufactured by Nippon Kayaku Co., Ltd. SR-444: liquid (viscosity at 25 ° C., 1280 mPa · s))
[A1-3] Bisphenol F type epoxy resin (Japan Epoxy Resin 806: Liquid (viscosity 2500mPa · s at 25 ° C))
[A1-4] Bisphenol A type epoxy resin (Japan Epoxy Resin 827: Liquid (viscosity at 25 ° C: 11000mPa · s))
[A1-5] Alkyl-type melamine resin (Nippon Cytec Industries, Ltd. Mycoat 506: Liquid (viscosity at 25 ° C: 2560 mPa · s))
[D1] Silane coupling agent (S-510, manufactured by Chisso Corporation)
[D2] Silicon-based surfactant (BYK330 manufactured by Big Chemi Japan)
[BDGAC] Diethylene glycol monobutyl ether acetate (boiling point 247 ° C)
[EDGAC] Diethylene glycol monoethyl ether acetate (bp 217 ° C)
[PGMEA] Propylene glycol monomethyl ether acetate (boiling point 146 ° C)

The following i) to v) are summarized in Table 2 for each ink composition obtained above.
i) Ratio of “pigment (B)” to “total of“ curable resin [(A3) + (A1)] ”and“ pigment (B) ”(% by weight)
ii) Ratio of "high boiling point solvent (C1) with a boiling point of 200 ° C or higher" (wt%) in all solvents
iii) Ratio of "polyfunctional liquid curable resin (A1)" in curable resin [(A3) + (A1)] (wt%)
iv) “Polyfunctional liquid curable resin (A1)” and “boiling point” for “total of curable resin [(A3) + (A1)]”, “pigment (B)” and “solvent (C)” "Total" of high boiling point solvents (C1) above 200 ° C (% by weight)
v) Ratio of “low boiling point solvent having a boiling point of less than 200 ° C.” (% by weight) in all solvents.

  Furthermore, using each ink composition obtained above, the ink composition was applied to the support substrate by an inkjet method as described below, and a colored film was formed for evaluation.

[Preparation of test substrate for liquid repellent treatment]
First, as a support substrate preparation, a photosensitive resin composition for forming color filter partition walls (black resist ink manufactured by Nippon Steel Chemical Co., Ltd.) is applied onto a glass substrate of 125 mm × 125 mm × 0.7 mm thickness using a spin coater. The film was applied so that the film thickness after post-baking was 2.2 μm and pre-baked at 80 ° C. for 1 minute. Thereafter, the exposure gap was adjusted to 80 μm, and a negative photomask with an opening of 400 μm × 150 μm and a partition line of 30 μm was covered on the dried coating film, and an I-line illuminance of 30 mW / cm ^{2 with} an ultrahigh pressure mercury lamp of 100 mj / A photocuring reaction of the exposed part was performed by irradiating with ultraviolet rays of cm ² . Next, this exposed coated plate is subjected to a 1 kgf / cm ² pressure shower development for 60 seconds or 80 seconds at 23 ° C. in a 0.05% aqueous potassium hydroxide solution and 5 kgf / cm ² pressure spray water washing to form a coating film. The unexposed portion was removed to form a pixel pattern on the glass substrate, and then heat post-baked at 230 ° C. for 30 minutes using a hot air dryer. Further, after treatment with oxygen atmospheric pressure plasma for 3 seconds, treatment was performed with CF ₄ atmospheric pressure plasma for 3 seconds to obtain a test support substrate having a liquid-repellent-treated partition wall. When the static contact angle was measured on the obtained black coating film (partition wall) using water or butyl carbitol acetate (BCA), it showed 100 ° and 50 °, respectively.

[Preparation of support substrate for test without liquid repellent treatment]
The post-baking is performed in the same manner as the production of the liquid repellent-treated test support substrate, and then only the treatment for 3 seconds with oxygen atmospheric pressure plasma is performed to obtain a test support substrate having a partition wall without liquid repellent treatment. It was. When the static contact angle was measured on the obtained black coating film (partition wall) using butyl carbitol acetate (BCA), it was 25 °.

[Evaluation of flatness of colored film]
Using an ink jet head (CA3) manufactured by Toshiba Tec Corporation, the ink compositions of Examples 1, 4, 5, Reference Examples 1 to 3 and Comparative Examples 1 to 5 were separated from the partition walls of the test support substrate obtained above. Is discharged into the space area partitioned by and prebaked at 80 ° C. for 5 minutes to form a colored film having an average film thickness of 0.75 to 0.95 times the thickness (height) of the partition wall did. About the obtained colored film, using a stylus-type film thickness meter (trade name: Surfcom, manufactured by Tokyo Seimitsu Co., Ltd.), in a space region partitioned by a partition wall (150 μm × 450 μm × height 2.2 μm (both inner diameters) The thickness (thickness) of the formed colored film is measured, and the flatness of the obtained colored film is determined from the height distribution curves in the XX ′ section and the YY ′ section shown in FIG. Evaluated.

  Among these, FIG. 4 shows respective height distribution curves in the XX ′ section and the YY ′ section direction of the colored film made of the ink composition of Comparative Example 1. In the XX ′ cross-sectional direction, the colored film has the highest portion near the partition wall 2 and its thickness is 2.25 μm. On the contrary, the lowest portion is near the center of the region partitioned by the partition wall. Its thickness was 1.15 μm. The same applies to the YY ′ cross-sectional direction, where the colored film has the highest portion near the partition wall 2 and the thickness thereof is 2.04 μm. On the contrary, in the vicinity of the center of the region partitioned by the partition wall 2. There was the lowest part and the thickness was 1.15 μm. In the case of the colored film of Comparative Example 1, the difference between the thickness of the highest part and the thickness of the lowest part was 1.10 μm after confirming the XX ′ section and the YY ′ section. In the height distribution curve, the part with an arrow represents the height of the partition wall.

On the other hand, FIG. 2 is a height distribution curve of the colored film made of the ink composition of Example 1. In the height distribution in the XX ′ cross-sectional direction, the partition walls 2 appearing in the case of Comparative Example 1 are shown. No swell or a dent at the center was confirmed, and the thickness of the highest part was 1.85 μm and the thickness of the lowest part was 1.72 μm. Further, in the height distribution in the YY ′ cross-sectional direction, the highest part is near the partition wall and the thickness is 1.95 μm, and the lowest part is near the center and the thickness is 1.87 μm. However, the difference between the thickness of the highest part and the thickness of the lowest part was 0.23 μm by confirming the XX ′ section and the YY ′ section. FIG. 3 is a height distribution curve of the colored film made of the ink composition of Reference Example 3. In the height distribution in the XX ′ cross-sectional direction, the thickness of the highest portion is 2.03 μm, and the vicinity of the center. On the other hand, in the height distribution in the YY ′ cross-sectional direction, the thickness of the lowest portion is 2.10 μm, and the thickness of the lowest portion near the center is 1.3 μm. It was 73 μm, and the difference between the thickness of the highest portion and the thickness of the lowest portion was 0.37 μm by confirming the XX ′ cross section and the YY ′ cross section. Similarly for other colored films, the height distribution curves in the XX ′ cross-sectional direction and the YY ′ cross-sectional direction are obtained, and the difference between the highest thickness and the lowest thickness is 0.4 μm or more. The flatness was evaluated in three stages, with x being ◯, 0.25 to 0.4 μm being ◯, and 0.25 μm or less being being ◎. The results are shown in Table 2.

[Measurement of contact angle to bulkhead]
In order to measure the contact angle of the ink composition with respect to the partition wall of the test substrate for liquid repellent treatment obtained above, the ink composition of Example 1 and the ink composition of Comparative Example 5 were heated at 23 ° C. and 60% humidity. Then, 0.5 μl of each was dropped from a syringe using a contact angle meter (OCA series manufactured by Eihiro Seiki Co., Ltd.), and the droplet edge angle after 1 second was measured after adhering to the partition wall. The results are shown in Table 2.

1: Support substrate 2: Partition wall 3: Colored film

Claims (4)

An ink composition used for forming a colored film by an ink jet method on a support substrate including at least a curable resin (A), a pigment (B), and a solvent (C) and having a plurality of space regions partitioned by partition walls. There,
In the component (A), at least one self-curable polyfunctional liquid curable resin selected from the group consisting of a liquid epoxy resin and a liquid melamine resin, which is bifunctional or higher, and at 25 ° C. The polyfunctional liquid curable resin (A1) having a viscosity of 6000 mPa · s or less is contained in an amount of 60% by weight or more, and the component (C) contains a high boiling point solvent (C1) having a boiling point of 200 ° C. or more in an amount of 80% by weight or more. Ratio [(A1) + (C1)] of [A1] component and (C1) component to total amount ((A) + (B) + (C)] of [A) to (C) [[(A1 ) + (C1)] / [(A) + (B) + (C)]] is 40% by weight or more.   The ratio [(B) / [(A) + (B)]] of the component (B) to the total [(A) + (B)] of the component (A) and the component (B) is 20 to 60% by weight. The ink composition according to claim 1. A method for forming a colored film by an inkjet method on a support substrate having a plurality of space regions partitioned by partition walls, using an ink composition containing at least a curable resin (A), a pigment (B), and a solvent (C) Because
The ink composition is at least one self-curable polyfunctional liquid curable resin selected from the group consisting of a liquid epoxy resin and a liquid melamine resin in the component (A), which is bifunctional or higher, and In addition, the polyfunctional liquid curable resin (A1) having a viscosity at 25 ° C. of 6000 mPa · s or less is contained by 60% by weight or more, and in the component (C), the high boiling point solvent (C1) having a boiling point of 200 ° C. or more is 80% by weight. % Of the total amount of the components (A) to (C) [(A) + (B) + (C)] of the sum of the components (A1) and (C1) [(A1) + (C1)] The ratio [[(A1) + (C1)] / [(A) + (B) + (C)]] is 40% by weight or more, and the contact angle to the partition wall is 30 ° or more to form a colored film. A method for forming a colored film characterized by the above. A colored film obtained by applying the ink composition according to claim 1 or 2 to a support substrate by an ink jet method, and drying and curing.

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