JP2008009401A - Resist composition for color filter, method for producing the same, and color filter using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive resin composition (resist) which allows formation of a thin line pattern excellent in development property and adhesion to a substrate, so that a black matrix for a color filter having high light blocking effect and high reliability can be created, and to provide a method for producing the composition. <P>SOLUTION: The resist composition for color filters comprises (A) an alkali-soluble resin compound containing an unsaturated group, (B) a photopolymerizable monomer having an ethylenically unsaturated bond, (C) a photopolymerization initiator, (D) a solvent and (E) a preliminarily prepared pigment dispersion, wherein the component (E) comprises (E1) a black colorant, (E2) a dispersant, (E3) a photosetting resin or a thermosetting resin and (E4) a solvent, a content of the component (E1) in all solid components in the composition is ≥40 wt.%, and the component (E3) or the component (A) is an acrylic resin having an acidic functional group. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a color filter resist composition, a method for producing the same, and a color filter using the same, and more particularly to a method for producing a photosensitive resin composition suitable for a black resist for a color filter.

  A color liquid crystal display device includes a liquid crystal unit for controlling the amount of light transmitted or reflected and a color filter as components, and the method for producing the color filter is usually black on the surface of a transparent substrate such as glass or plastic sheet. Next, a method is used in which different colors of red, green, and blue are sequentially formed in a color pattern such as a stripe shape or a mosaic shape. The pattern size varies depending on the use of the color filter and each color, but red, green, and blue pixels are thinned to 100 μm or less, and the black matrix is thinned to 10 μm or less. With this, the photosensitive resin material has high dimensional accuracy. It has been demanded.

  In recent years, color liquid crystal display devices have been used in various fields such as liquid crystal televisions, liquid crystal monitors, and color liquid crystal mobile phones. The color filter is one of the important members that influence the visibility of the color liquid crystal display device. In order to improve the visibility, that is, to obtain a clear image, the color filters such as red, green, and blue are used. It is necessary to achieve higher color purity of the pixel and higher light shielding with the black matrix than before, and it is necessary to add a colorant to the photosensitive resin composition in a larger amount than before.

  However, when the content of the colorant is increased, it becomes difficult for light in the ultraviolet region to reach the deep part of the coating film when forming a color filter, particularly in a black resist film, and poor adhesion of the pattern due to poor curing in the photocurable composition. There arises a problem that pattern peeling occurs during development and sharpness loss of the edge shape occurs.

  Therefore, a highly sensitive photopolymerization initiator or an acrylic monomer having a high degree of polymerization may be used so that curing failure does not occur even when a high concentration of colorant is included. However, with the current technology, the photopolymerization initiator and the acrylic monomer are at the limit of increasing the sensitivity, and it is very difficult to achieve high light shielding of the black matrix. Therefore, it is required to achieve high sensitivity for alkali-soluble resins, and to obtain a pattern with good pattern dimensional stability, pattern adhesion, and pattern edge shape sharpness with a wide development margin. Yes. In addition, as for a dispersant for dispersing a high-concentration colorant, good development solubility and high adhesion to a substrate at the time of development are required. Sufficient patterning characteristics are not obtained.

Japanese Unexamined Patent Publication No. 1-152449 JP-A-7-278214 JP 2001-264530 A JP 2002-323762 A JP 2003-96118 A JP 2004-10838 A JP 2003-270785 A Japanese Patent Laid-Open No. 10-301276 JP-A-9-197663 JP-A-9-95638 Japanese Unexamined Patent Publication No. 7-3122

  In Patent Document 1, halomethyloxadiazole compounds and halomethyl-S-triazine compounds are used as high-sensitivity photopolymerization initiators in order to prevent a decrease in sensitivity while increasing the pigment concentration and achieving good color reproducibility. An example of use is disclosed. However, although these compounds are improved in surface flatness due to reaction inhibition by oxygen, they still do not reach a satisfactory level in terms of pattern dimensional accuracy. Patent Documents 2 to 5 disclose examples in which an oxime ester-based photopolymerization initiator is used in a photosensitive resin composition as a high-sensitivity photopolymerization initiator. Therefore, it is difficult to form a good pattern with a photosensitive resin composition containing a high concentration of colorant.

  Moreover, although the Example of the photosensitive resin composition for color filters which has a bisphenol fluorene structure is shown by the said patent documents 6-11, sufficient in order to perform a favorable pattern formation in a high concentration pigment area | region. Sensitivity, adhesion and storage stability are not obtained.

  Accordingly, an object of the present invention is to provide a color filter resist composition that solves the above-described problems and has high sensitivity, high adhesion performance, and high storage stability in a region containing a high concentration of colorant that achieves high light shielding. It is to provide. Moreover, it is providing the photosensitive resin composition for resists for black matrices. Another object of the present invention is to provide a coating film and a color filter formed using an alkali developing type photosensitive resin composition.

  As a result of studies conducted by the present inventors to solve the above-mentioned problems, the above-mentioned problems are solved by making specific resins used for pigment dispersion and co-dispersing them with a dispersant. The present invention has been completed.

The present invention includes the following components (E1) to (E4),
(E1) at least one colorant selected from black organic pigments, mixed-color organic pigments and light-shielding materials,
(E2) dispersant,
(E3) a photocurable resin or a thermosetting resin,
(E4) After preparing a (E) pigment dispersion consisting of a solvent in advance, the following components (A) to (D) as essential components:
(A) an unsaturated group-containing alkali-soluble resin,
(B) a photopolymerizable monomer having an ethylenically unsaturated bond,
(C) a photopolymerization initiator,
(D) A method for producing a resist composition for a color filter, which comprises mixing with a solvent.

  The color filter resist composition of the present invention exhibits further excellent performance by satisfying any one or more of the following requirements.

（ここで、Ｒ₁、Ｒ₂、Ｒ₃、Ｒ₄は、独立に水素原子、炭素数１〜５のアルキル基、ハロゲン原子又はフェニル基を示し、Ｒ₅は水素原子又はメチル基を示す。また、Aは-CO-、-SO₂-、-C(CF₃)₂-、-Si(CH₃)₂-、-CH₂-、-C(CH₃)₂-、-O-、9,9-フルオレニル基又は直結合を示し、Xは4価のカルボン酸残基を示し、Y₁、Y₂は独立に水素原子又は-OC-Z-(COOH)_mで示されるカルボン酸残基（mは1〜3の数を示す）を示し、nは1〜20の数を示す。）で表される不飽和基含有アルカリ可溶性樹脂であること。
2） (A)成分の少なくとも1部が、上記一般式（I）で表される不飽和基含有アルカリ可溶性樹脂であること。 1) At least one part of component (E3) is a reaction product of an epoxy compound having two glycidyl ether groups derived from bisphenols and (meth) acrylic acid, and a) a dicarboxylic acid or its acid anhydride and b The following general formula (I) obtained by reacting tetracarboxylic acid or its acid dianhydride in a range where the molar ratio of a / b is 0.1-10

(Here, R ₁ , R ₂ , R ₃ and R ₄ independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a halogen atom or a phenyl group, and R ₅ represents a hydrogen atom or a methyl group. A is -CO-, -SO _2- , -C (CF ₃ ) _2- , -Si (CH ₃ ) _2- , -CH _2- , -C (CH ₃ ) _2- , -O-, 9 , 9-fluorenyl group or a direct bond, X represents a tetravalent carboxylic acid residue, Y ₁ and Y ₂ are independently a hydrogen atom or a carboxylic acid residue represented by -OC-Z- (COOH) _m (M represents a number from 1 to 3), and n represents a number from 1 to 20.)
2) At least one part of the component (A) is an unsaturated group-containing alkali-soluble resin represented by the general formula (I).

The present invention also provides a photosensitive resin composition for a black resist, comprising the above-described color filter resist composition.
Furthermore, this invention is the coating film formed by hardening | curing said photosensitive resin composition for black resists.
Moreover, this invention is a black matrix obtained by developing the photosensitive resin composition for black resists with an alkaline developer.
Furthermore, the present invention is a color filter formed with the above black matrix.

  Hereinafter, the resist composition for a color filter or the photosensitive resin composition for a black resist of the present invention (hereinafter, both are also referred to as a resist composition) will be described in detail. The resist composition of the present invention is a photosensitive resin composition and can be alkali developed.

  The resist composition of the present invention contains the above components (A) to (E) as essential components. Here, the component (A) is an unsaturated group-containing alkali-soluble resin (hereinafter referred to as an alkali-soluble resin), and the component (B) is a photopolymerizable monomer having an ethylenically unsaturated bond (hereinafter referred to as a photopolymerizable monomer). ), (C) component is a photopolymerization initiator, (D) component is a solvent, and (E) component is a pigment dispersion.

The alkali-soluble resin of component (A) may be an alkali-soluble resin having an unsaturated group, but has an unsaturated group derived from (meth) acrylic acid, and a) a dicarboxylic acid or an acid anhydride thereof And b) an alkali-soluble resin having an acidic group derived from a tetracarboxylic acid or an acid dianhydride thereof (hereinafter sometimes abbreviated as a tetracarboxylic acid). . One or more of these alkali-soluble resins can be used.
In the present specification, the acid component means the above dicarboxylic acids, tetracarboxylic acids or both, and (meth) acrylic acid means acrylic acid, methacrylic acid or both.

  A preferred alkali-soluble resin as component (A) is a compound obtained by reacting an epoxy compound having two glycidyl ether groups derived from bisphenols with (meth) acrylic acid, resulting in a compound having a hydroxy group. It is an epoxy (meth) acrylate acid adduct obtained by reacting at least one of dicarboxylic acids and tetracarboxylic acids as basic acids. Since the component (A) has both an ethylenically unsaturated double bond and a carboxyl group, it gives an excellent photocurability, good developability, and patterning characteristics to the alkali development type photosensitive resin composition, and a good black matrix. Is obtained. The most preferred alkali-soluble resin is a resin represented by the above general formula (I).

Such an alkali-soluble resin is preferably derived from an epoxy compound represented by the general formula (II). This epoxy compound is derived from bisphenols.

In the general formula (II), R ₁ , R ₂ , R ₃ , R ₄ and A have the same meaning as in the general formula (I). Preferred R ₁ , R ₂ , R ₃ and R ₄ are hydrogen atoms, and preferred A is a 9,9-fluorenyl group. l is an integer of 0 to 10, preferably 0 or 0 to 2 as an average value. Here, the 9,9-fluorenyl group refers to a group represented by the following formula (III).

  Examples of the bisphenols that give the alkali-soluble resin as the preferred component (A) include the following. Bis (4-hydroxyphenyl) ketone, bis (4-hydroxy-3,5-dimethylphenyl) ketone, bis (4-hydroxy-3,5-dichlorophenyl) ketone, bis (4-hydroxyphenyl) sulfone, bis (4 -Hydroxy-3,5-dimethylphenyl) sulfone, bis (4-hydroxy-3,5-dichlorophenyl) sulfone, bis (4-hydroxyphenyl) hexafluoropropane, bis (4-hydroxy-3,5-dimethylphenyl) Hexafluoropropane, bis (4-hydroxy-3,5-dichlorophenyl) hexafluoropropane, bis (4-hydroxyphenyl) dimethylsilane, bis (4-hydroxy-3,5-dimethylphenyl) dimethylsilane, bis (4- Hydroxy-3,5-dichlorophenyl) dimethylsilane, bis (4-hydroxyphenyl) methane, bis (4-hydroxy-3,5-dichlorophenyl) Methane, bis (4-hydroxy-3,5-dibromophenyl) methane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2 , 2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxy-3-chlorophenyl) propane, Bis (4-hydroxyphenyl) ether, bis (4-hydroxy-3,5-dimethylphenyl) ether, bis (4-hydroxy-3,5-dichlorophenyl) ether and the like. In addition, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene, 9,9-bis (4- Hydroxy-3-chlorophenyl) fluorene, 9,9-bis (4-hydroxy-3-bromophenyl) fluorene, 9,9-bis (4-hydroxy-3-fluorophenyl) fluorene, 9,9-bis (4- Hydroxy-3,5-dimethylphenyl) fluorene, 9,9-bis (4-hydroxy-3,5-dichlorophenyl) fluorene, 9,9-bis (4-hydroxy-3,5-dibromophenyl) fluorene, etc. are also preferred Can be mentioned. Furthermore, 4,4′-biphenol, 3,3′-biphenol and the like are also preferred.

  The component (A) can be obtained from an epoxy compound derived from bisphenols as described above. In addition to such an epoxy compound, a phenol novolac type epoxy compound, a cresol novolak type epoxy compound, etc. are also two glycidyl ethers. Any compound that significantly contains a compound having a group can be used. In addition, when bisphenols are glycidyl etherified, oligomer units are mixed. If the average value of l in formula (II) is in the range of 0 to 10, preferably 0 to 2, this resin composition There is no problem in the performance of things.

  The reaction between such an epoxy compound and (meth) acrylic acid is carried out using about 2 moles of (meth) acrylic acid with respect to 1 mole of the epoxy compound. It is known. The reaction product obtained by this reaction is an epoxy (meth) acrylate compound represented by the following formula (V) as well as described in the above-mentioned patent documents.

  The reaction product obtained by the reaction between the epoxy compound and (meth) acrylic acid is reacted with the acid component to obtain an alkali-soluble resin as the component (A). As the acid component, a) dicarboxylic acids and b) tetracarboxylic acids that can react with the hydroxy group in the epoxy (meth) acrylate compound molecule are used.

Here, as a) dicarboxylic acids, chain hydrocarbon dicarboxylic acid or its acid anhydride, alicyclic dicarboxylic acid or its acid anhydride, aromatic dicarboxylic acid or its acid anhydride is used.
Examples of the chain hydrocarbon dicarboxylic acid or its acid anhydride include succinic acid, acetyl succinic acid, maleic acid, adipic acid, itaconic acid, azelaic acid, citralmalic acid, malonic acid, glutaric acid, citric acid, tartaric acid, oxoglutar There are compounds such as acid, pimelic acid, sebacic acid, suberic acid, diglycolic acid and the like, and further dicarboxylic acids having an arbitrary substituent introduced therein or acid anhydrides thereof may be used.
Examples of the alicyclic dicarboxylic acid or its acid anhydride include compounds such as hexahydrophthalic acid, cyclobutane dicarboxylic acid, cyclopentane dicarboxylic acid, norbornane dicarboxylic acid, and any substituents introduced. Dicarboxylic acids or acid anhydrides thereof may be used.
Furthermore, examples of the aromatic dicarboxylic acid and its acid anhydride include compounds such as phthalic acid and isophthalic acid, and further dicarboxylic acids into which an arbitrary substituent is introduced or acid anhydrides thereof may be used.

In addition, as b) tetracarboxylic acids, chain hydrocarbon tetracarboxylic acid or its acid dianhydride, alicyclic tetracarboxylic acid or its acid dianhydride, or aromatic polyvalent carboxylic acid or its acid dianhydride Things are used.
Here, examples of the chain tetracarboxylic acid or its acid anhydride include butanetetracarboxylic acid, pentanetetracarboxylic acid, hexanetetracarboxylic acid, and the like, and further, tetracarboxylic acids having a substituent introduced therein or acids thereof. An anhydride may be used. Examples of the alicyclic tetracarboxylic acid or its acid anhydride include cyclobutanetetracarboxylic acid, cyclopentanetetracarboxylic acid, cyclohexanetetracarboxylic acid, cycloheptanetetracarboxylic acid norbornanetetracarboxylic acid, and the like. It may be a tetracarboxylic acid having a substituent introduced therein or an acid anhydride thereof.
Furthermore, examples of the aromatic tetracarboxylic acid and acid anhydride thereof include pyromellitic acid, benzophenone tetracarboxylic acid, biphenyl tetracarboxylic acid, biphenyl ether tetracarboxylic acid, and acid anhydrides thereof, and further, substituents thereof. The introduced tetracarboxylic acids or acid anhydrides thereof may be used.

  One or more of a) dicarboxylic acids and b) tetracarboxylic acids can be used, respectively. The use ratio of a) dicarboxylic acids and b) tetracarboxylic acids is 0.1 to 10 as a molar ratio of a / b. The range is preferably 0.2 to 1.0. The use ratio can be selected as the optimum molecular weight, alkali developability, light transmittance, heat resistance, solvent resistance, and the pattern shape effect, but the higher the use ratio of tetracarboxylic acids, the higher the alkali solubility. Tend to be large and have a high molecular weight.

The method for producing the component (A) by reacting the reaction product obtained by the reaction between the epoxy compound and (meth) acrylic acid and the acid component is not particularly limited, and the above-mentioned Patent Documents 6 to 11 are not limited. A publicly known method as described in the above can be adopted.
Advantageously, it is desirable to carry out the reaction quantitatively by using an acid component in an amount that shows an acid value, which will be described later, so that the carboxy group is equal to or more equivalent to the hydroxy group in the epoxy (meth) acrylate compound molecule. . The reaction temperature is 90 to 130 ° C, preferably 95 to 125 ° C.

An example of the method for producing the component (A) is as follows when 9,9-bis (4-hydroxyphenyl) fluorene is used as a starting material.
First, 9,9-bis (4-hydroxyphenyl) fluorene and epichlorohydrin are reacted to synthesize a bisphenolfluorene type epoxy compound represented by the following general formula (IV). A bisphenolfluorene type epoxy acrylate resin represented by the following general formula (V) was synthesized by reacting with (meth) acrylic acid represented by CH ₂ = CR ₅ -COOH, and then bisphenolfluorene in a propylene glycol monomethyl solvent. The epoxy acrylate resin and the acid component are reacted under heating to obtain a fluorene type alkali-soluble resin represented by the formula (I) as the component (A).

Here, in the formulas (IV) and (V), R ₁ , R ₂ , R ₃ , R ₄ and R ₅ have the same meaning as in the formula (I). A represents a 9,9-fluorenyl group.

  The resist composition of the present invention contains the component (A) as an essential component of the resin component. Here, the resin component refers to a component that becomes a resin by polymerization or curing, and includes a monomer in addition to a resin (including an oligomer). The component (A) is preferably contained in an amount of 15 to 25 wt% in the total solid content of the resist composition. The weight average molecular weight (Mw) is preferably between 500 and 10,000. If the weight average molecular weight (Mw) is less than 500, the pattern adhesion during development cannot be maintained and pattern peeling occurs. If the weight average molecular weight (Mw) exceeds 10,000, the adhesion to the glass substrate is high. As a result, the residue and the remaining film of the pattern portion are likely to remain. Furthermore, the component (A) preferably has an acid value in the range of 1 to 200 KOHmg / g. When this value exceeds 200 KOHmg / g, the permeation of the alkali developer is accelerated, and thus the peeling development occurs. The total solid content does not include a volatile component such as a solvent, but includes a monomer that is polymerized or cured to become a solid component.

  Examples of the photopolymerizable monomer of the component (B) include monomers having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (Meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tetramethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylol Ethanetri (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol (Meth) acrylic acid esters such as rutetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, glycerol (meth) acrylate, and the like. These photopolymerizable monomers may be used alone or in combination. Can be used. The photopolymerizable monomer of component (B) does not have a free carboxy group.

  The mixing ratio of the component (A) and the component (B) is preferably 20/80 to 90/10 in weight ratio (A) / (B), and preferably 40/60 to 80/20. When the blending ratio of the component (A) is small, the cured product after photocuring becomes brittle, and the acid value of the coating film is low in the unexposed area, so the solubility in an alkali developer is lowered, and the pattern edge is scratched. When the problem of not being sharp and sharp occurs, the ratio of the photoreactive functional group in the resin is small and the formation of a crosslinked structure is insufficient, and the acid value in the resin component is too high, and the alkali in the exposed area Since the solubility in the developer is increased, there is a possibility that the formed pattern is narrower than the target line width or the pattern is easily lost.

As the photopolymerization initiator of component (C), one or more kinds of initiators can be used. In addition, the photoinitiator said by this invention is used by the meaning containing a sensitizer.
Usable photopolymerization initiators include, for example, acetophenones such as acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, dichloroacetophenone, trichloroacetophenone, p-tert-butylacetophenone Benzophenones such as benzophenone, 2-chlorobenzophenone, p, p'-bisdimethylaminobenzophenone, benzoin ethers such as benzyl, benzoin, benzoin methyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2- (o-chlorophenyl) ) -4,5-phenylbiimidazole, 2- (o-chlorophenyl) -4,5-di (m-methoxyphenyl) biimidazole, 2- (o-fluorophenyl) -4,5-diphenylbiimidazole, 2 -(o-methoxyphenyl)- Biimidazole compounds such as 4,5-diphenylbiimidazole, 2,4,5-triarylbiimidazole, 2-trichloromethyl-5-styryl-1,3,4-oxadiazole, 2-trichloromethyl- Halomethylthiazole compounds such as 5- (p-cyanostyryl) -1,3,4-oxadiazole, 2-trichloromethyl-5- (p-methoxystyryl) -1,3,4-oxadiazole, 2,4,6-tris (trichloromethyl) -1,3,5-triazine, 2-methyl-4,6-bis (trichloromethyl) -1,3,5-triazine, 2-phenyl-4, 6- Bis (trichloromethyl) -1,3,5-triazine, 2- (4-chlorophenyl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (4-methoxyphenyl) -4 , 6-Bis (trichloromethyl) -1,3,5-triazine, 2- (4-methoxynaphthyl) -4,6-bis (trichloroRmethyl) -1,3,5-triazine, 2- (4- Methoxystyryl) -4,6- (Trichloromethyl) -1,3,5-triazine, 2- (3,4,5-trimethoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine, 2- (4 -Methylthiostyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine and other halomethyl-S-triazine compounds, 1,2-octanedione, 1- [4- (phenylthio) phenyl] -, 2- (o-benzoyloxime), 1- (4-phenylsulfanylphenyl) butane-1,2-dione-2-oxime-o-benzoate, 1- (4-methylsulfanylphenyl) butane-1, O-acyloxime compounds such as 2-dione-2-oxime-o-acetate and 1- (4-methylsulfanylphenyl) butan-1-oneoxime-o-acetate, benzyldimethyl ketal, thioxanthone, 2-chlorothio Xanthone, 2,4-diethylthioxanthone, 2-methylthioxanthone, 2-isopropylthioxone Organic compounds such as 2-ethylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, anthraquinones such as 2,3-diphenylanthraquinone, organic peroxidation such as azobisisobutylnitrile, benzoyl peroxide, cumene peroxide Products, thiol compounds such as 2-mercaptobenzimidazole, 2-mercaptobenzoxazole and 2-mercaptobenzothiazole, and tertiary amines such as triethanolamine and triethylamine.

  The amount of the photopolymerization initiator used as the component (C) is preferably 2 to 60 parts by weight, preferably 10 to 50 parts by weight based on the total of 100 parts by weight of the components (A) and (B). It is. When the blending ratio of the component (C) is small, the photopolymerization rate is slowed and the sensitivity is lowered.On the other hand, when the amount is too large, the sensitivity is too strong and the pattern line width becomes thicker than the pattern mask. On the other hand, there may be a problem that a faithful line width cannot be reproduced or the pattern edge is not rattling and sharp.

  Examples of the solvent for component (D) include alcohols such as methanol, ethanol, n-propanol, isopropanol, ethylene glycol, and propylene glycol, terpenes such as α- or β-terpineol, acetone, methyl ethyl ketone, cyclohexanone, N -Ketones such as methyl-2-pyrrolidone, aromatic hydrocarbons such as toluene, xylene, tetramethylbenzene, cellosolve, methylcellosolve, ethylcellosolve, carbitol, methylcarbitol, ethylcarbitol, butylcarbitol, propylene Glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monomethyl ether, Glycol ethers such as ethylene glycol monoethyl ether, ethyl acetate, butyl acetate, cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, carbitol acetate, ethyl carbitol acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, propylene glycol mono Examples include acetic acid esters such as ethyl ether acetate, and the like, and these can be dissolved and mixed to form a uniform solution-like composition.

The pigment dispersion of component (E) includes the following components.
(E1) at least one colorant selected from black organic pigments, mixed color organic pigments and light-shielding materials (hereinafter referred to as colorants),
(E2) Dispersant
(E3) Photo-curing resin or thermosetting resin (hereinafter referred to as curable resin)
(E4) Solvent

  (E) component, (E1) component, (E2) component, (E3) component, (E4) component and other components added if necessary, after adding media such as glass beads, zirconia beads, A paint conditioner, a sand grounder, a ball mill, a roll mill, a stone mill, a jet mill, a homogenizer, an ultrasonic wave and the like are preferably obtained by being subjected to dispersion treatment alone or in combination. This dispersion treatment makes the pigment component fine particles and stabilizes the dispersion, so that the light shielding ability of the resist composition and the coating characteristics can be improved.

  The component (E) is preferably dispersed until the components (E2) and (E3) are first dissolved in an optimal amount of the component (E4), and then the component (E1) is added and stabilized.

  The secondary particle diameter after dispersion is preferably adjusted so that the dispersed particle diameter of the component (E1), for example, carbon black, is 50 to 200 nm, preferably 80 to 150 nm. The dispersed particle diameter here is, for example, an average particle diameter obtained by a known laser Doppler type particle size measuring device. Further, the viscosity of the dispersion is adjusted to 3.0 to 100.0 mPa · s, preferably 3.0 to 20.0 mPa · s at a liquid temperature of 25 ° C. when calculated from a known cone plate type viscosity type. It is preferable to do this.

  Examples of the black organic pigment used as the colorant for the component (E1) include perylene black and cyanine black. Examples of mixed color organic pigments include those obtained by mixing at least two pigments selected from red, blue, green, purple, yellow, cyanine, magenta and the like into a pseudo black color. Examples of the light shielding material include carbon black, chromium oxide, iron oxide, titanium black, aniline black, and cyanine black. Two or more colorants can be appropriately selected and used, but carbon black is particularly preferable in terms of good light shielding properties, surface smoothness, dispersion stability, and compatibility with the resin.

  Specifically, carbon black # 2400, # 2350, # 2300, # 2200, # 1000, # 980, # 970, # 960, # 950, # 900, # 850, MCF88, # 650, MA600 manufactured by Mitsubishi Chemical Corporation , MA7, MA8, MA11, MA100, MA220, MA230, IL30B, IL31B, IL7B, IL11B, IL52B, # 4000, # 4010, # 55, # 52, # 50, # 47, # 45, # 44, # 40, # 33, # 32, # 30, # 20, # 10, # 5, CF9, # 3050, # 3150, # 3250, etc. Carbon black thermax N990, N991, N907, N908, N990, N991, N908 made by Cancarb. Carbon black Asahi # 80, Asahi # 70, Asahi # 70L, Asahi F-200, Asahi # 66, Asahi # 66HN, Asahi # 60H, Asahi # 60U, Asahi # 60, Asahi # 55, Asahi # 50H, Asahi # 51, Asahi # 50U, Asahi # 50, Asahi # 35, Asahi # 15, Asahi Thermal. Carbon black ColorBlack Fw200, ColorBlack Fw2, ColorBlack Fw2V, ColorBlack Fw1, ColorBlack Fw18, ColorBlack S170, ColorBlack S160, SpecialBlack6, SpecialBlack5, SpecialBlack4, SpecialBlack4A, SpecialBlack250, SpecialBlack350, PrintexU, PrintexV, Printex140U, Printex140V (all product names) ) And the like.

  The content of the colorant of the (E1) component is (E1) / [(A) + (B) + (C) + (E ')] × 100. The weight content of the (E1) component is 40 wt%. It mix | blends so that it may become the above. Preferably it is 45-60 wt%, More preferably, it is the range of 50-55 wt%. Here, (E ′) is a component obtained by removing (E4) component from (E) component. In the above calculation formula, (E1), (A), (B), (C), and (E ′) are blending amounts (weight) of each component. When the content of the component (E1) is low, the light shielding property is not sufficient, and in order to obtain a desired contrast, the film thickness must be increased, and the surface smoothness of the black matrix is difficult to obtain. On the other hand, if the amount added is too large, not only the pigment dispersion of component (E), but also the dispersion stability of the resist composition is lowered, and the content of the photosensitive resin that is the original binder is also reduced. There is a possibility that an undesired problem that good development characteristics cannot be obtained may occur.

  The dispersant of the component (E2) may be any dispersant as long as it has an action of stably dispersing the colorant of the component (E1) as a pigment dispersion.For example, a known dispersant such as various polymer dispersants is used. can do. Specific examples of the polymer dispersant include polymer dispersants having basic functional groups such as primary, secondary or tertiary amino groups, nitrogen-containing heterocycles such as pyridine, pyrimidine and pyrazine.

  The curable resin of component (E3) contains at least one photocurable resin or thermosetting resin. The curable resin of component (E3) can be co-dispersed with the dispersant using a photocurable resin or a thermosetting resin in combination with the aforementioned dispersant. The component (E3) is preferably an acrylic resin having an acidic functional group, and it is more effective that part or all of the component (E) is the same as the component (A). When (E2) component and (E3) component are co-dispersed, along with the added amount, viscosity stability over time and line width stability will be good, and effects such as residue reduction, linearity improvement, adhesion improvement etc. Is obtained.

  As the solvent for the component (E4), it is desirable to use the same solvent as the solvent for the component (D).

  In the production of the resist composition of the present invention, after the preparation of the above component (E), it is mixed with the component (A), the component (B), the component (C), the component (D) and a compounding component added as necessary, to obtain a resist composition. It is desirable to make it. This mixing may be performed by any method that allows uniform mixing, but can be performed by using a dispersing device or the like used for stirring and component (E) preparation.

  Further, in the production of the resist composition of the present invention, a curing accelerator, a thermal polymerization inhibitor, a plasticizer, a filler, a leveling agent, an antifoaming agent, a surfactant different from that for the dispersant, etc., as necessary. Additives can be blended. Examples of the thermal polymerization inhibitor include hydroquinone, hydroquinone monomethyl ether, pyrogallol, tert-butylcatechol, phenothiazine, and the like, and examples of the plasticizer include dibutyl phthalate, dioctyl phthalate, tricresyl, and the like. Can include glass fiber, silica, mica, alumina, and the like, and examples of the antifoaming agent and leveling agent include silicon-based, fluorine-based, and acrylic compounds.

  The resist composition of the present invention can be obtained by the method for producing a resist composition of the present invention. Further, the pigment dispersion of the present invention can be obtained by the method for producing the component (E). This pigment dispersion is advantageously used in the production of the resist composition of the present invention.

  The resist composition of the present invention contains the components (A) to (E) as main components. In the solid content excluding the solvent (the solid content includes monomers that become solid content after curing), the total of components (A) to (E) is 70 wt% or more, preferably 80 wt%, more preferably 90 wt% or more It is desirable to include. The amount of solvent varies depending on the target viscosity, but is preferably in the range of 20 to 90 wt%.

  The resist composition of the present invention is useful as a resist for a color filter, for example, an ink, a light-shielding film, etc., but is suitable for a photosensitive resin composition for a black resist for a color filter (hereinafter also referred to as a black resist composition). .

  The coating film of the present invention can be obtained, for example, by applying the above black resist composition solution to a substrate or the like, drying it, irradiating it with light (including ultraviolet rays, radiation, etc.) and curing it. A coating film having a desired pattern can be obtained by providing a portion that is exposed to light and a portion not exposed to light, curing only the portion that is exposed to light, and dissolving the other portion with an alkaline solution.

  Next, a method for producing a color filter using the black resist composition of the present invention will be described. First, on the surface of the substrate, a black resist composition is applied to the substrate, and a light-shielding layer (black matrix) is formed so as to partition a portion for forming a pixel. Next, after applying a liquid photosensitive resin composition (ink) in which, for example, a red pigment is dispersed on the substrate, pre-baking is performed to evaporate the solvent, thereby forming a coating film. Next, after exposing the coating film through a photomask, development using an alkaline developer is performed to dissolve and remove the unexposed portion of the coating film, and then post-baking to form a predetermined red pixel pattern. A pixel array arranged in an array is formed. Thereafter, using the ink in which the green or blue pigment is dispersed, the liquid composition is applied, pre-baked, exposed, developed, and post-baked in the same manner as described above to obtain the green pixel array and the blue pixel array. By sequentially forming on the same substrate, a pixel array of three primary colors of red, green and blue is disposed on the substrate, and further, a liquid composition of a photosensitive resin not containing a colorant is formed thereon as a protective film. In the same manner as described above, coating, pre-baking, exposure, development, and post-baking are performed to obtain a color filter on which a protective film is formed.

  When applying the liquid composition of the resist composition or black resist composition of the present invention to the substrate, in addition to the known solution dipping method and spray method, roller coater, land coater, slit coater, spin coater, screen printing method Alternatively, any method such as an ink jet printing method can be adopted. After applying to a desired thickness by these methods, the film is formed by removing the solvent (pre-baking). Pre-baking is performed by heating with an oven, a hot plate or the like, vacuum drying, or a combination thereof. The heating temperature and the heating time in the pre-baking are appropriately selected according to the solvent used, and for example, the heating is performed at a temperature of 80 to 120 ° C. for 1 to 10 minutes.

  As the radiation used for exposing and curing the resist composition when producing the color filter, for example, visible light, ultraviolet light, far ultraviolet light, electron beam, X-ray, and the like can be used. Radiation in the range of 250-450 nm is preferred. Next, although alkali development is performed, examples of the developer suitable for alkali development include aqueous solutions of alkali metal and alkaline earth metal carbonates, aqueous solutions of alkali metal hydroxides, and the like. It is better to develop at a temperature of 20-30 ° C using a weakly alkaline aqueous solution containing 0.05-10% by weight of carbonate such as sodium carbonate, potassium carbonate, lithium carbonate, etc. It can be used to form a fine image precisely. In addition, it is usually washed with water after alkali development. As a development processing method, a shower development method, a spray development method, a dip (immersion) development method, a paddle (liquid accumulation) development method, or the like can be applied. The development conditions are preferably 10 to 120 seconds at room temperature.

  After the development as described above, a heat treatment (post-bake) is performed at a temperature of 180 to 250 ° C. and a condition of 20 to 100 minutes. This post-baking is performed for the purpose of improving the adhesion between the patterned coating film and the substrate. This is performed by heating with an oven, a hot plate or the like, as in the pre-baking. The patterned coating film of this invention is formed through each process by the above photolithography method.

  As a substrate used when forming a color filter having pixels and a black matrix, for example, a transparent electrode such as ITO or gold on glass or a transparent film (for example, polycarbonate, polyethylene terephthalate, polyether sulfone, etc.) is used. A vapor-deposited or patterned material is used. In addition, these substrates may be subjected to appropriate pretreatment such as chemical treatment with a silane coupling agent or the like, plasma treatment, ion plating, sputtering, gas phase reaction method, vacuum deposition, etc., if desired.

  The black matrix of the present invention can be obtained by coating, drying, exposing and developing as described above using the above black resist. The color filter of the present invention can be obtained by using the color ink on the black matrix and repeating the steps of coating, drying, exposure and development as described above.

  The resist composition for a color filter of the present invention enables formation of a fine line pattern having excellent development characteristics and substrate adhesion, and when applied to a color filter, creates a black matrix having high light shielding properties and high reliability. It becomes possible. Therefore, it is suitable for various multicolor displays such as color liquid crystal display devices, color facsimiles, and image sensors, inks used for optical devices, etc., color filters having a black matrix, televisions, video monitors, computer displays, etc. Can be used for

Hereinafter, the present invention will be described in more detail with reference to synthesis examples, examples, and comparative examples. In addition, evaluation of resin in the following synthesis examples is as follows unless otherwise noted.
Solid content concentration: Obtained by heating the resin solution at 160 ° C. for 2 hours.
Acid value: Determined by titration with 1/10 N-KOH ethanol (50%) aqueous solution.
Molecular weight: determined by GPC. This molecular weight is the weight average molecular weight (Mw) in terms of polystyrene of the component (A) excluding unreacted raw materials.

The abbreviations used in the synthesis examples are as follows.
FHPA: Equivalent reaction product of fluorene bisphenol type epoxy resin and acrylic acid (manufactured by Nippon Steel Chemical Co., Ltd., ASF-400 solution: solid content concentration 50wt%, solid content converted acid value 1.3mgKOH / g, epoxy equivalent 21300 )
ODPA: 4,4'-oxydiphthalic dianhydride
SA: Succinic anhydride
TPP: Triphenylphosphine
PGMEA: Propylene glycol monomethyl ether acetate

Synthesis example 1
In a 500 ml four-necked flask with a reflux condenser, 222.13 g (1 eq) of FHPA in PGMEA, 42.45 g (0.75 eq) ODPA, 9.18 g (0.5 eq) SA, 25.73 g PGMEA and 0.47 g TPP (0.01 eq) ) And stirred for 2 hours while heating at 120 to 130 ° C., and further heated and stirred for 6 hours at 80 to 90 ° C. to synthesize an alkali-soluble resin solution (A) -2. The obtained resin solution had a solid content of 55 wt%, an acid value (in terms of solid content) of 150 mgKOH / g, and a Mw of 10,000 by GPC analysis.

The raw materials and abbreviations used in the production of the color filters of Examples and Comparative Examples are as follows.
Component (A) -I: Propylene glycol monomethyl ether acetate solution of acid anhydride polycondensate of epoxy acrylate having a fluorene skeleton (resin solid concentration = 56.5% by weight, molecular weight Mw = 3,500, acid value 100 mgKOH / g, Shinichi (Product name V259ME, manufactured by Sakai Chemical Co., Ltd.)
Component (A) -II: Alkali-soluble resin solution (A) -2 obtained in Synthesis Example 1
Component (B): A mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (trade name DPHA, manufactured by Nippon Kayaku Co., Ltd.)
Ingredient (C): O-acyloxime photopolymerization initiator (manufactured by Ciba Specialty, Irgacure OXE-02)
Ingredient (D): PGMEA
Ingredient (E1) -I: MA14 (Mitsubishi Chemical Corporation)
Ingredient (E1) -II: Special Black 350 (Degussa)
Ingredient (E2): Dispersant A: DisperK-182 Modified acrylic block copolymer (amine value 13 mgKOH / g, manufactured by BYK Chemie)
Component (E3) -I: Same as component (A) -I Component (E3) -II: Same component (A) -II Component (E4): PGMEA
Additive I: Surfactant additive II: Silane coupling agent

Examples 1-26 and Comparative Examples 1-10
The said compounding component was mix | blended in the weight ratio as described in Tables 1-6, and the resin composition of Examples 1-26 and Comparative Examples 1-10 was prepared.
First, dissolve the (E2) component and (E3) component of the formulation shown in Tables 1-6 in the (E4) component, then add the (E1) component, and use a bead mill using 0.1 mm glass beads as the media. Then, while cooling the vessel by circulating cooling water, dispersion was performed at room temperature until the dispersion state became stable, to prepare (E) a pigment dispersion.
Next, the components (A), (B), (C), (D) and other additives described in Tables 1 to 6 and the previously prepared (E) pigment dispersion were uniformly mixed to obtain photosensitivity. A resin composition (resist composition) was obtained.
In addition, in the order of Tables 1 to 6, the (E1) component content is 40 wt%, 45 wt%, 50 wt%, 52 wt%, 55 wt%, 57 wt%.

The photosensitive resin composition obtained by uniformly mixing the blending components of Examples and Comparative Examples was applied on a 125 mm × 125 mm glass substrate using a spin coater so that the film thickness after post-baking was 1.0 μm. Then, after pre-baking at 80 ° C. for 1 minute, the photo-curing reaction of the photosensitive part was performed by irradiating with 10 mj / cm ² of ultraviolet light with an ultra-high pressure mercury lamp with I-line illuminance of 30 mW / cm ² . Next, this exposed coated plate is subjected to 0.1 MPa pressure shower development for 60 seconds at 25 ° C. in 0.1% potassium hydroxide aqueous solution and spray water washing at 0.5 MPa pressure to remove unexposed portions of the coating film, and developability Was evaluated. Thereafter, a film for color filter application was prepared by hot post-baking at 230 ° C. for 30 minutes using a hot air dryer, and developability evaluation and pattern shape evaluation were performed.

  Moreover, the physical-property evaluation as a black photosensitive resin composition of the resin composition in each Example and a comparative example was performed as follows.

* Film thickness: measured using a stylus type step shape measuring device (trade name P-15, manufactured by KLA-Tencor Corporation).
* 10 μm line width reduction rate (line width reduction rate): The film formed was dried and exposed, and 10 μm fine line patterning was performed by alkali development, and the line width was measured. Further, after the resist was stored at 40 ° C. for 3 days, patterning was performed in the same manner, and the line thinning state when the line width was measured was shown as a 10 μm line width reduction rate. In this case, the line width was measured using a length measuring microscope (trade name XD-20 manufactured by Nikon Corporation). However, measurement was not possible for samples that could not be measured because a 10 μm fine line pattern did not remain.
* Residue: The case where black foreign matter derived from carbon remained on the developed glass substrate was marked with ○, the case where the amount was relatively small, Δ, and the case where the amount was very large, x.
* Linearity: 10μm fine line pattern with good linearity after heat treatment after development, ◯ with good but partially chipped or fringed (backlash), with many chips and fringes, linearity Those that could not be maintained were evaluated as x <defect>.
* Adhesion: Post-baked pattern-formed substrate is subjected to PCT (pressure cooker) test under conditions of 121 ° C, 100% RH, 2atm, 24 hours, and then cellophane tape is applied to the 20μm pattern area for peeling. The pattern adhesion was evaluated by performing a test.
* Comprehensive evaluation: ○ <Good>, △ <Slightly good>, × <Bad>
The evaluation results are shown in Tables 1 to 6 together with the composition.

  When the (E1) component content was 40 wt%, the overall evaluation was a good result. When it was 45 wt%, the developability and linearity were affected in the comparative example, and the overall evaluation was Δ, but in the example, all were good results ○. When it was 50 wt%, the developability and linearity were affected in the comparative example, and the overall evaluation was x, but in the examples, the residue and linearity began to be affected, but the adhesion was good. The overall evaluation was good.

  In the case of 52 wt%, a 10 μm fine line pattern was not obtained after development in the comparative example, and the comprehensive evaluation was impossible, but in the example using both the dispersants (E2) and (E3), the ratio of E3 In Examples 16 to 18 with high values, good results were obtained, and in Examples 19 to 20 with a low E3 ratio, the evaluation of the residue was x, and the evaluation of linearity and adhesion was Δ, so the overall evaluation was Δ. It was. In the case of 55 wt% and 57 wt%, in the comparative example, a 10 μm fine line pattern was not obtained after development, and the comprehensive evaluation was impossible to measure, but in the examples using both (E2) and (E3) Evaluation was △.

  From the above results, when the content of component (E1) is 40 wt%, no significant effect appears even if the dispersant is replaced with (E3) and co-dispersed, but when it exceeds 45 wt%, the effect of the co-dispersion appears, residue, It turns out that it has an effect on the linearity and the adhesion of the fine wires. In addition, when describing the resist, it was found that the stability after 3 days at 40 ° C. is higher when (E3) is contained and the degree of thinning of the 10 μm fine wire is lower than when the dispersant alone. It was.

Claims (10)

The following (E1) to (E4) components,
(E1) at least one colorant selected from black organic pigments, mixed-color organic pigments and light-shielding materials,
(E2) dispersant,
(E3) a photocurable resin or a thermosetting resin,
(E4) After preparing a (E) pigment dispersion consisting of a solvent in advance, the following components (A) to (D) as essential components:
(A) an unsaturated group-containing alkali-soluble resin,
(B) a photopolymerizable monomer having an ethylenically unsaturated bond,
(C) a photopolymerization initiator,
(D) A method for producing a resist composition for a color filter, comprising mixing a compounding component containing a solvent and (E) a pigment dispersion. (E3) component is an acrylic polymer having an acidic functional group, and the following calculation formula
(E1) / [(A) + (B) + (C) + (E ')] × 100
(However, (E ') is a component obtained by removing (E4) component from (E) component, and (E1), (A), (B), (C), (E') in the above formula is (Represents the amount (weight) of each component)
The method for producing a resist composition for a color filter according to claim 1, wherein the content of the component (E1) calculated by the formula (1) is 40 wt% or more. (E3) At least one part of the component is a reaction of an epoxy compound having two glycidyl ether groups derived from bisphenols and (meth) acrylic acid, and a) dicarboxylic acid or its acid anhydride and b) tetra The following general formula (I) obtained by reacting a carboxylic acid or an acid dianhydride in a range where the molar ratio of a / b is 0.1 to 10.

(Here, R ₁ , R ₂ , R ₃ and R ₄ independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a halogen atom or a phenyl group, and R ₅ represents a hydrogen atom or a methyl group. A is -CO-, -SO _2- , -C (CF ₃ ) _2- , -Si (CH ₃ ) _2- , -CH _2- , -C (CH ₃ ) _2- , -O-, 9 , 9-fluorenyl group or a direct bond, X represents a tetravalent carboxylic acid residue, Y ₁ and Y ₂ are independently a hydrogen atom or a carboxylic acid residue represented by -OC-Z- (COOH) _m The color filter resist composition according to claim 1 or 2, which is an unsaturated group-containing alkali-soluble resin represented by (wherein m represents a number from 1 to 3) and n represents a number from 1 to 20. Manufacturing method.   4. The color filter resist composition according to claim 1, wherein at least one part of the component (A) is an unsaturated group-containing alkali-soluble resin represented by the general formula (I) in claim 3. Production method. The following (E1) to (E4) components,
(E1) at least one colorant selected from black organic pigments, mixed-color organic pigments and light-shielding materials,
(E2) dispersant,
(E3) a photocurable resin or a thermosetting resin,
(E4) a pre-prepared (E) pigment dispersion comprising a solvent, and the following components (A) to (D) as essential components:
(A) an unsaturated group-containing alkali-soluble resin,
(B) a photopolymerizable monomer having an ethylenically unsaturated bond,
(C) a photopolymerization initiator,
(D) A resist composition for a color filter, comprising a blending component containing a solvent.   A photosensitive resin composition for a black resist, comprising the resist composition for a color filter according to claim 5.   A coating film formed by curing the photosensitive resin composition for a black resist according to claim 6.   A black matrix obtained by developing the photosensitive resin composition for a black resist according to claim 6 with an alkali developer.   A color filter in which the black matrix according to claim 8 is formed. The following (E1) to (E4) components,
(E1) at least one colorant selected from black organic pigments, mixed-color organic pigments and light-shielding materials,
(E2) dispersant,
(E3) a photocurable resin or a thermosetting resin,
(E4) A (E) pigment dispersion comprising a solvent, wherein at least one part of the (E3) component is an epoxy compound having two glycidyl ether groups derived from bisphenols and (meth) acrylic acid The following general formula (I) obtained by reacting a reactant with a) dicarboxylic acid or its acid anhydride and b) tetracarboxylic acid or its acid dianhydride in a range where the molar ratio of a / b is 0.1-10. )

(Here, R ₁ , R ₂ , R ₃ and R ₄ independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a halogen atom or a phenyl group, and R ₅ represents a hydrogen atom or a methyl group. A is -CO-, -SO _2- , -C (CF ₃ ) _2- , -Si (CH ₃ ) _2- , -CH _2- , -C (CH ₃ ) _2- , -O-, 9 , 9-fluorenyl group or a direct bond, X represents a tetravalent carboxylic acid residue, Y ₁ and Y ₂ are independently a hydrogen atom or a carboxylic acid residue represented by -OC-Z- (COOH) _m (M represents a number from 1 to 3), and n represents a number from 1 to 20.) A pigment dispersion which is an unsaturated group-containing alkali-soluble resin represented by: