JP2000028820A - Ink for production of color filter and color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the stability of ink injection, contrast, light resistance, whether resistance, reliability or the like, especially in the pixel forming process by an ink-jet method, by incorporating at least a solvent and a soluble pigment precursor. SOLUTION: This ink is used to be applied by an ink-jet method on the substrate for the formation of a color filter, and it contains at least a soluble pigment precursor and a solvent as the components. As for the soluble pigment precursor, a coloring agent which is originally soluble like a dye in a solvent and which becomes a solvent-insoluble pigment or has a structure similar to a pigment after the solubility promoting groups are released is used. The resin to be incorporated is not specified, and an acrylic base and an epoxy base polyamic acids or hydrophilic resins of them can be used. As for the acrylic resin, a single acrylic polymer may be used, or it may contain an amino base resin such as melamines and guanamines as a hardening agent so as to further improve the durability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink for producing a color filter and a color filter, and more particularly, to an ink for producing a color filter by an ink jet method using a soluble pigment precursor which can be converted into an insoluble pigment. And a color filter produced using the ink.

[0002]

2. Description of the Related Art A color filter for a liquid crystal display element is composed of a number of picture elements, with three primary color pixels formed on a transparent substrate as one picture element. A light-shielding region (generally black and referred to as a black matrix) having a certain width is provided between the pixels to increase the display contrast.

[0003] Color filter production methods include a method of dyeing a dyeable medium formed by a photolithography method, a method of using a pigment-dispersed photosensitive composition, an electrodeposition method using a patterned electrode, and a low-pressure method. Cost manufacturing methods include a printing method and an ink-jet method of forming a colored portion using an ink-jet ink jetting apparatus.

[0004] Among the conventional manufacturing methods, the printing method and the ink-jet method have fewer steps and are lower in cost than the dyeing method and the pigment dispersion method in which pixels are formed one by one by photolithography. The ink jet method includes a method of forming a pixel by discharging an ink in which a dye is dissolved into a layer to be dyed and dyeing the dye, and then fixing the ink. There is a method in which the pixel is formed by curing by means of (1).

[0005] However, a color filter formed by an ink-jet method using an ink containing a dye has high contrast, high color purity and high transmission, but has poor light resistance, weather resistance, heat resistance, and the like. However, since general dyes are dissolved only in an aqueous solvent, the types of resins used for the layer to be dyed are limited, and a water-insoluble resin often used as a resin for a color filter cannot be applied. On the other hand, a color filter by an inkjet method using an ink using a pigment has excellent reliability, but dispersibility of the pigment is poor, and the color performance is not as good as that using a dye. In some cases, nozzle clogging due to pigment aggregation may occur, which has been a problem in terms of ink ejection stability.

Among the various problems, problems arising from the essential properties of pigments and dyes, such as reliability such as color performance, light fastness, weather fastness and heat resistance, can be solved by, for example, Japanese Patent Application Laid-Open No. An example of a color filter using a soluble pigment precursor is described in 7-150068. However, the publication only describes an ink-jet method as an example of a method for producing various color filters.
No mention is made of solutions to problems such as nozzle clogging.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a method for forming an ink, particularly in a pixel forming process by an ink jet method, because there is no nozzle clogging. An object of the present invention is to provide an ink which is capable of providing a color filter which has excellent discharge stability, high contrast, high color purity and high transmission, and also has good reliability such as light resistance, weather resistance and heat resistance. .

[0008]

Means for Solving the Problems To solve the above problems, the paste for producing a color filter of the present invention has the following constitution.

That is, an ink used for manufacturing a color filter for forming pixels by discharging ink on a substrate by an ink-jet method, wherein the ink contains at least a solvent and a soluble pigment precursor. is there.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The ink for producing a color filter of the present invention is an ink used for application on a substrate for forming a color filter by an ink jet method, and has at least a soluble pigment precursor and a solvent as constituent elements, Depending on the color filter manufacturing method, a resin may be further included as a component. The description will be made in the following order. However, the present invention is not limited to these items.

As a substrate for forming a color filter, a transparent substrate such as soda glass, non-alkali glass, borosilicate glass, and quartz glass, and a semiconductor substrate such as silicon and gallium-arsenic are usually used. Not done. When applying the ink on a color filter forming substrate, a silane coupling agent,
If the surface of the substrate is treated with an adhesion aid such as an aluminum chelating agent or a titanium chelating agent, the adhesive strength of the substrate can be improved, and this is performed as needed. Also,
As will be described later, a substrate provided with an ink mixing prevention fence and a black matrix which is a light shielding layer between pixels can be used more favorably.

The soluble pigment precursor is a substance which is soluble in a solvent like a dye as it is, and can be converted into a pigment by, for example, chemical, photolytic or thermal means. The soluble pigment precursor is described in, for example, JP-A-7-1500.
68, JP-A-7-188234, JP-A-8-6242,
As described in JP-A-9-3362 and JP-A-9-31076, the chromophore skeleton has a structure in which a side chain for promoting solvent solubility is introduced. By appropriately selecting the optimal chromophore skeleton, various colors used for the color filter can be provided. The present invention is characterized by using a pigment which is dissolved in a solvent in the ink but has a solubility-promoting group which is later removed and has a solvent-insoluble pigment or a structure similar to a pigment, and has such properties. If it is a coloring agent, it can be preferably used as a whole. Examples of coloring agents that can be used below are given.

The soluble pigment precursor that can be used in the present invention is:
For example, those having a structure such as A (B) x can be preferably used.

Here, x is an integer of 1 to 4, and A,
That is, the pigment skeleton is the residue of known nitrogen-containing chromophores and known derivatives of those chromophores. For example, phthalocyanine, quinacridone, anthraquinone, perylene,
Residues of indigo, quinophthalone, isoindolinone, isoindoline, dioxazine, diketopyrrolopyrrole, or azo series colorants, which are x groups B through a nitrogen atom that is part of A Is joined to.
However, when the pigment skeleton is a phthalocyanine skeleton, a compound in which B is not bonded via a nitrogen atom may be preferably used, which will be described later in detail.

B, that is, the side chain that promotes solvent solubility is represented by any of the following formulas.

[0016]

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Embedded image Details of each of Expressions 1 to 3 will be described in order.

First, in the formula 1, m, n and p are each independently 0 or 1, X is C ₁ -C ₄ alkylene or C ₂ -C ₈ alkenylene, and Y is a group -V
— (CH ₂ ) q—, wherein V is C ₃ -C ₆ cycloalkylene, q is 1-6, R ₁ and R ₂ are each independently hydrogen, C ₁ -C ₆ alkyl a C ₁ -C ₄ alkoxy, halogen, CN, nO _2, substituted or not, or C ₁ -C ₄ alkyl, phenyl substituted by C ₁ -C ₄ alkoxy or halogen, or phenoxy.

In the formula 2, m and n independently represent 0
Or 1 and X is C ₁ -C ₄ alkylene or C _2-
C ₈ alkenylene, and Z represents a group —V— (CH ₂ ) r—
In and, V wherein is C ₃ -C ₆ cycloalkylene, r is a number from 0 to 6. Q is hydrogen, CN, Si
(R ₁ ) ₃ , a group C (R ₅ ) (R ₆ ) (R ₇ ) (where R ₅ , R
₆ and R ₇ are each independently hydrogen or halogen, and at least one of R ₅ , R ₆ and R ₇
Is a halogen) or a group of the formula

Embedded image Wherein R ₁ and R ₂ have the meanings given above, the radical SO ₂
R ₈ , or SR _8, where R ₈ is C ₁ -C ₄ alkyl, a group CH (R ₉ ) _2, wherein R ₉ is unsubstituted or C ₁ -C ₄ alkyl , C ₁ -C ₄
Phenyl substituted by alkoxy or halogen), or any one of the following formulas 5 to 12.

[0019]

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Embedded image In the equation 1 or 2, when X is C ₁ -C ₄ alkylene, it may be straight or branched alkylene. For example: methylene, dimethylene, trimethylene, 1-methyl-methylene, 1,1-dimethylmethylene, 1,1-dimethyl-trimethylene, 1
-Ethyl-dimethylene, 1-ethyl-1-methyl-dimethylene, tetramethylene, 1,1-dimethyl-tetramethylene, 2,2-dimethyl-trimethylene, hexamethylene, decamethylene, 1,1-dimethyl-decamethylene, 1, 1-diethyl-decamethylene, tetradecamethylene.

When X is C ₂ -C ₈ alkenylene, it can be straight-chain or branched alkenylene. For example: vinylene, allylene, metalylene, 1-methyl-2-butenylene, 1,1-dimethyl-
3-butenylene, 2-butenylene, 2-hexenylene,
3-hexenylene or 2-octenylene. C3-C6
Cycloalkylene is, for example, cyclopropylene, cyclopentylene, and especially cyclohexylene.

In the formula 3, R ₃ and R ₄ are each independently hydrogen, C ₁ -C ₁₈ alkyl or a group of the following formula:

Embedded image Wherein X, Y, R ₁ , R ₂ , m, and n have the above meanings, or R ₃ and R ₄ together with the nitrogen atom to which they are attached are a pyrrolidinyl group, Forming a piperidinyl or morpholinyl group;

The description of the example B and the expressions 1 to 3 has been completed.

In addition, A (B) x is additionally represented by the following groups:

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Embedded image Or, -NH ₂ - may contain groups. Not all nitrogen atoms need be bonded to group B, and often are not. Alternatively, one or more groups B can be attached to one nitrogen atom.

Among the compounds having the A (B) x structure, x = 2 is particularly preferably used, and B is any of the following formulas.

[0025]

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Embedded image Particularly preferred soluble pigment precursors for use include the following.

When A is a phthalocyanine skeleton,
The following formula

Embedded image (Where X ₁ is Ni, Fe, V, preferably H ₂ , Z
n or a Cu,, X ₂ is -CH (R ₂ ') -, preferably -CH ₂ - is or SO _2, R _1' is C ₁ -C ₄ alkyl, -N (E ₁₎ R ₂ ', -NHCOR ₃ ', -CO
R ₃ 'or

Embedded image And a, preferably hydrogen, -NHCOCH ₃ or benzoyl, R ₂ 'is hydrogen or C ₁ -C ₄ alkyl, R _3' is C ₁ -C ₄ alkyl, R ₄ 'is hydrogen,
Halogen, C ₁ -C ₄ alkyl or C ₁ -C ₄ alkoxy, wherein z is 0 or 1, preferably 1.
y is an integer of 1 to 4, E ₁ is hydrogen or B described above, and at least one E ₁ means B).

When A is other than phthalocyanine skeleton,

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Embedded image Wherein E ₂ is —C (＝ O) —O—C (CH ₃ ) ₃ ;
₁₀ and R ₁₁ are preferably, independently of each other, hydrogen, halogen, C ₁ -C ₅ alkyl or C ₁ -C ₄ alkoxy, and R ₂₃ and R ₂₄ are hydrogen, halogen, C ₁ -C ₅ Alkyl, C ₁ -C ₄ alkoxy, phenyl, or cyano, and particularly preferably, R ₁₀ , R ₁₁ , R ₂₃ and R ₂₄ are hydrogen or chlorine.

B is not bonded via a nitrogen atom,
Examples of the soluble pigment precursor having a phthalocyanine skeleton include those represented by the following formula.

[0029]

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Embedded image Wherein L ₁ and L ₂ are independently halogen, C ₁ -C
_C18 alkoxy, substituted by C ₁ -C _{1 8} alkylthio, C ₁ -C ₁₈ alkylamino, C ₂ -C ₁₈ dialkylamino, or unsubstituted or one or two of C ₁ -C ₁₂ alkyl group, A 5- or 6-membered imino ring, which contains zero or one additional nitrogen or oxygen atom, and M is two hydrogen atoms,
Two monovalent metals or metals having a divalent or higher valence, y is a number from 0 to 16 and each Z is independently of each other halogen, C ₁ -C ₁₈ alkoxy,
C ₁ -C ₁₈ alkylthio, C ₁ -C ₁₈ alkyl or C ₂
When carrying out the -C ₁₈ dialkylamino present invention, as the component of the colorant of the present invention, as a color filter of desired color, a single compound or two or more soluble pigment precursor Body combinations can be used. In addition, pigments and dyes other than the soluble pigment precursor may be used together, but care must be taken since there is a concern that the above-described drawbacks may be caused. In general, a color filter often uses a combination of three colors of red, green, and blue, or often uses a combination of three colors of cyan, magenta, and yellow.
A single or a combination of two or more soluble pigment precursors that provide insoluble pigments of these colors can be preferably used.

As means for converting the soluble pigment precursor used in the ink of the present invention into an insoluble pigment, a resin layer containing the soluble pigment precursor is formed as described above, followed by photolytic or thermal means. It is preferable to remove the solubility-promoting group. In many cases, it can be performed simultaneously with the curing step of the resin. In order to perform insoluble pigmentation by thermal means, for example, first, preferably at least 100 ℃, more preferably 120 ℃ or more, more preferably 140 ℃ or more, to some extent insoluble pigmentation, more preferably 160 A method of completing insoluble pigment formation at a temperature of at least 180 ° C, more preferably at least 180 ° C, still more preferably at least 200 ° C, is preferred. Alternatively, a method of continuously increasing the temperature from a low temperature to a high temperature may be used.

As the solvent that can be used in the ink for producing a color filter of the present invention, all solvents that are usually used are considered. It is desirable that the soluble pigment precursor is completely dissolved in the solvent, but the ink of the present invention can be used without any problem even if it is not completely dissolved. Examples of usable solvents include hydrocarbons, alcohols, amides, nitriles, nitro compounds, N-heterocyclic compounds, ethers, ketones, and esters. Specifically, for example, methanol, ethanol, isopropanol, ethylene glycol, diethylene glycol, diethyl ether, acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 1,2-dimethoxyethane, 1,2-diethoxyethane, 2-methoxyethanol , Ethyl acetate, tetrahydrofuran, dioxane, acetonitrile, benzonitrile, nitrobenzene, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone, γ-butyrolactone, pyridine, picoline, quinoline, trichloroethane, benzene , Toluene, xylene, anisole, chlorobenzene and the like.
In particular, toluene, methanol, ethanol, isopropanol, ethylene glycol, diethylene glycol,
Cyclopentanone, N-methylpyrrolidone, 1,2-dimethoxyethane, 1,2-diethoxyethane, acetone, methyl ethyl ketone, ethyl acetate, tetrahydrofuran, and dioxane have high solubility and are preferred. Further, these solvents may be used as a mixed solvent of two or more kinds. At that time, it is preferable that the above-mentioned particularly preferable solvent is contained as a component. In addition, when a hydrophilic resin is contained in the ink, or when the hydrophilic resin needs to be impregnated with the ink of the present invention, it is preferable to use water as a solvent.

As a method of manufacturing the color filter of the present invention, for example, the following two methods can be considered. That is, 1. Ink is ejected on the color filter forming substrate on which the ink receiving layer is formed by an ink jet method,
1. a method in which a pixel is formed by impregnating a soluble pigment precursor and then converting the soluble pigment precursor into an insoluble pigment; In this method, an ink containing a resin is ejected onto a color filter forming substrate by an inkjet method, and the ink is fixed by curing the resin and the soluble pigment precursor is converted into an insoluble pigment to form pixels. In the case of the first method, it is not always necessary to include a resin in the ink. In the case of the second method, it is preferable that the resin be contained in the ink.

First, in the case of the first manufacturing method, as the resin for forming the ink receiving layer, any resin which can be impregnated with ink can be preferably used as a whole. An organic solvent-soluble resin can be used, and a hydrophilic resin generally used in a method for producing a color filter by a dyeing method can also be used. Specifically, synthetic resins such as polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl acetal, polyurethane, carboxymethyl cellulose, polyester, polyacrylic acid (ester), hydroxyethyl cellulose, hydroxypropyl cellulose, melamine resin, or modified products thereof, Examples include, but are not limited to, natural resins such as albumin, gelatin, casein, starch, cationized starch, gum arabic, and sodium alginate. Further, the invention is not limited thereto, and a plurality of resins can be used simultaneously. Further, in order to further improve the resistance, a curing agent such as an amino-based resin such as melamines and guanamines or an acrylic polyfunctional monomer as a curing agent, or an adhesion improver may be included, as described later. May contain a reaction accelerator such as an acid generator that promotes the insolubilization of the soluble pigment precursor in the step after ink impregnation.

The method for forming the ink receiving layer on the substrate for forming a color filter is not particularly limited, and a general coating method may be used. For example, spin coating, roll coating, bar coating, spray coating, dip coating, a printing method, and the like can be used. One surface may be coated, or if possible, one surface may be coated and then patterned into a desired shape by photolithography. For example, it is preferable to perform patterning for each pixel because the ink does not spread beyond a desired area during ink impregnation. Alternatively, a method in which an ink receiving layer is formed only in a desired region by an inkjet method without using a photolithographic method is also preferably used.

The ink used in the first method comprises at least a soluble pigment precursor and a solvent, and may contain a resin in some cases. As the solvent used for the ink, it is preferable to select a solvent having a high impregnation property to the ink receptor according to the ink receptor used. For example,
If a hydrophilic resin is used as the ink receiver, water,
It is preferable to use a solvent containing at least a water-soluble solvent such as alcohol. Alternatively, if an organic solvent-soluble resin such as polyacrylate, polyimide, polyamide, or polyacrylamide is used, it is preferable to use an organic solvent having a high impregnation property in accordance with the resin. The solid content concentration of the ink is preferably adjusted as appropriate according to the solubility of the soluble pigment precursor to be used and the type of the inkjet coating device.

Thus, the ink of the present invention is discharged and impregnated on the ink receiver by an ink jet method, and further, the soluble pigment precursor is converted into a pigment by the method described above.
Form a color filter. Further, a step of fixing the color filter layer by heat curing or the like may be included.

In the case of the production method 2, the resin that can be contained in the ink for producing a color filter of the present invention is not particularly limited, and for example, resins commonly used in color filters can be preferably used. That is, resins such as acrylic resins, epoxy resins, polyamic acids, and the above-mentioned hydrophilic resins can be preferably used.
Depending on the resin used, a photo-curable or thermo-curable ink can be used and can be appropriately selected according to the color filter manufacturing process.

The composition will be described in detail by taking an acrylic resin as an example. As the acrylic resin, an acrylic polymer alone is also preferable, but in order to further improve resistance, a melamine, an amino resin such as guanamine or an acrylic polyfunctional monomer as a curing agent, and a photopolymerization initiator are included. Is also good. When an amino resin is contained, a thermosetting ink can be obtained, and when a polyfunctional monomer and a photopolymerization initiator are contained, a photocurable ink can be obtained.

The acrylic polymer is not particularly limited, but a copolymer of an unsaturated carboxylic acid and an ethylenically unsaturated compound can be preferably used. Examples of unsaturated carboxylic acids include, for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid,
Vinyl acetic acid, acid anhydride and the like can be mentioned.

These may be used alone or in combination with other copolymerizable ethylenically unsaturated compounds. Specific examples of the copolymerizable ethylenically unsaturated compound include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, isopropyl acrylate, n-propyl methacrylate, and methacrylic acid. Isopropyl, n-butyl acrylate, n-butyl methacrylate, s-acrylate
ec-butyl, sec-butyl methacrylate, iso-butyl acrylate, iso-butyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate,
N-pentyl acrylate, n-pentyl methacrylate,
Unsaturated carboxylic acid alkyl esters such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, benzyl acrylate and benzyl methacrylate; fragrances such as styrene, p-methyl styrene, o-methyl styrene, m-methyl styrene and α-methyl styrene Aromatic vinyl compounds, unsaturated carboxylic acid aminoalkyl esters such as aminoethyl acrylate, glycidyl acrylate, unsaturated carboxylic acid glycidyl esters such as glycidyl methacrylate, vinyl acetate, carboxylic acid vinyl esters such as vinyl propionate, acrylonitrile, methacrylonitrile, vinyl cyanide compounds such as α-chloroacrylonitrile; aliphatic conjugated dienes such as 1,3-butadiene and isoprene; acryloyl groups at the terminals; Or macromonomers such as polystyrene, polymethyl acrylate, polymethyl methacrylate, polybutyl acrylate, polybutyl methacrylate, and polysilicone having a methacryloyl group, but are not limited thereto.

The use of an acrylic polymer having an ethylenically unsaturated group added to the side chain improves the reliability such as hardness and solvent resistance, and is therefore preferably used.
Examples of the ethylenically unsaturated group include a vinyl group, an allyl group, an acryl group, and a methacryl group. As a method for adding such a side chain to an acrylic (co) polymer, when the acrylic (co) polymer has a carboxyl group or a hydroxyl group, an ethylenically unsaturated compound having a glycidyl group in these groups is used. Or an addition reaction of acrylic acid or methacrylic acid chloride.
In addition, a compound having an ethylenically unsaturated group can be added using isocyanate. Examples of the ethylenically unsaturated compound having a glycidyl group and acrylic acid or methacrylic acid chloride include glycidyl acrylate, glycidyl methacrylate, glycidyl α-ethyl acrylate, crotonyl glycidyl ether,
Glycidyl ether of crotonic acid, glycidyl ether of isocrotonic acid, acrylic acid chloride, methacrylic acid chloride and the like can be mentioned.

Examples of the polyfunctional monomer include bisphenol A diglycidyl ether (meth) acrylate, poly (meth) acrylate carbamate, modified bisphenol A epoxy (meth) acrylate, adipic acid 1,6-hexanediol (meth) acrylic acid Ester, phthalic anhydride propylene oxide (meth) acrylate, trimellitate diethylene glycol (meth) acrylate, rosin-modified epoxy di (meth) acrylate, alkyd-modified (meth) acrylate or oligomer such as tripropylene glycol di ( (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, bisphenol A diglycidyl ether di (meth) acrylate, trimethylolpropane tri (meth) Acrylate, pentaerythritol tri (meth) acrylate, triacrylformal, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate. These can be used alone or in combination. In addition, the following monofunctional monomers can also be used in combination. For example, ethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, hydroxyethyl (meth) acrylate, n-butyl methacrylate, glycidyl methacrylate, lauryl ( Meth) acrylate, stearyl (meth) acrylate, isobornyl (meth) acrylate, etc.
A mixture of two or more of these, a mixture with another compound, or the like is used. In particular, a methacrylate compound is preferable to an acrylate compound for increasing the hardness.

The photopolymerization initiator is not particularly limited.
Known ones can be used, for example, benzophenone, N,
N′-tetraethyl-4,4′-diaminobenzophenone, 4-methoxy-4′-dimethylaminobenzophenone, 2,2-diethoxyacetophenone, benzoin,
Benzoin methyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, α-hydroxyisobutylphenone, thioxanthone, 2-chlorothioxanthone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl]-
2-morpholino-1-propane, t-butylanthraquinone, 1-chloroanthraquinone, 2,3-dichloroanthraquinone, 3-chloro-2-methylanthraquinone, 2-ethylanthraquinone, 1,4-naphthoquinone, 9,10-fe Nantraquinone, 1,2-benzoanthraquinone, 1,4-dimethylanthraquinone, 2-
Phenylanthraquinone, 2- (o-chlorophenyl)
And -4,5-diphenylimidazole dimer. In addition, other acetophenone-based compounds, imidazole-based compounds, benzophenone-based compounds, thioxanthone-based compounds, phosphorus-based compounds, triazine-based compounds, and inorganic photopolymerization initiators such as titanates can also be preferably used. Further, it is preferable to add a sensitizing aid such as p-dimethylaminobenzoic acid ester since the sensitivity can be further improved. Further, two or more of these photopolymerization initiators can be used in combination.
Among the photopolymerization initiators, the type that generates an acid by light can be particularly preferably used because it promotes the formation of a soluble pigment precursor into a pigment as described later.

The amount of the photopolymerization initiator is not particularly limited, but is preferably 1 to 3 with respect to the total solid content of the ink.
0 wt%, more preferably 5 to 25 wt%, further preferably 10 to 20 wt%.

In the ink of the present invention used in the production method 2, the resin component and the colorant containing at least the soluble pigment precursor are usually in a weight ratio of 1: 9 to 9: 1, preferably 2: 9. 8-8: 2, more preferably 3: 7-7:
3 are used as a mixture. If the amount of the resin component is too small, the adhesion to the substrate becomes poor, and if the amount of the colorant is too small, the degree of coloring becomes a problem. In addition, in the ink, it is preferable to appropriately adjust the solid content concentration of the resin component and the pigment so that the ink viscosity range is suitable for the ink jet coating method used. The preferred range of the solid concentration is 2 to 30%, more preferably 3 to 30%.
It is used in the range of 25%, more preferably 5 to 20%.

The ink of the present invention is ejected onto a substrate for forming a color filter by an ink jet method,
Alternatively, after the photo-curing or at the same time as this step, a color filter is formed by forming the soluble pigment precursor into a pigment by the method described above.

The basic structure of the two cases in the color filter forming method of the present invention has been described above. Hereinafter, means for obtaining a higher quality color filter in both methods will be described.

The ink for producing a color filter of the present invention may contain, as a resin component, a catalyst for promoting the formation of a soluble pigment precursor into an insoluble pigment. Examples of such catalysts include acids or acid generators, or bases or base generators. However, when a resin having an acid group such as an acrylic resin or a hydrophilic resin is used as the resin, since the resin itself is an acid, the pigmentation can be favorably performed without particularly adding a pigmentation accelerator. Let it proceed. Alternatively, in the case of the first manufacturing method, a catalyst may be previously contained in the ink receiving layer.

In the ink for producing a color filter of the present invention, the soluble pigment precursor is dissolved in a solvent.
Unlike ink obtained by the pigment dispersion method, the ink has low viscosity instead of high viscosity, and has high leveling property because of no thixotropy. Therefore, the ink may bleed beyond the desired area, which may cause a problem. In order to prevent such a phenomenon, it is preferable to use, as a color filter forming substrate, a substrate in which a black matrix is formed to provide a step with a step between ink discharge locations. The black matrix is not particularly limited, and may be a metal-based black matrix such as chromium, chromium oxide, or a laminated film of chromium oxide and chromium nitride, or a material containing iron oxide. The resin black matrix having the configuration is preferable because the height of the step is higher. The resin used for the resin black matrix is not particularly limited, and may be an acrylic resin,
A known material such as a polyimide-based material can be used. Also, the light-shielding agent is not limited, and a general one such as carbon black or titanium oxide can be used. In addition, there is no problem with a black matrix using a soluble pigment precursor as a light-shielding agent. In order to more effectively prevent color mixing, a color mixing prevention fence may be provided between pixels.
In the case of the first manufacturing method using an ink receiving layer as the color mixing preventing fence, for example, as described in JP-A-8-75916, an ink receiving layer in which the degree of ink impregnation changes by light irradiation is used. In the case of the second manufacturing method, a resin fence may be physically installed by a photolithographic method as described in, for example, JP-A-7-49414 and JP-A-8-179110. . Also, if the color mixing prevention fence is installed on a black matrix,
Further, color mixing can be prevented more effectively.

It is preferable to add a surfactant to the ink for producing a color filter of the present invention because it has an effect of improving ink coating properties, wettability, and drying properties, and has an effect of preventing color mixing. The amount of the surfactant added is usually 0.001 of the soluble pigment precursor.
It is 1 to 10% by weight, preferably 0.01 to 1% by weight. Specific examples of the surfactant include ammonium lauryl sulfate, anionic surfactant such as polyoxyethylene alkyl ether triethanolamine sulfate, stearylamine acetate, cationic surfactant such as lauryl trimethyl ammonium chloride, lauryl dimethylamine oxide, Amphoteric surfactants such as lauryl carboxymethylhydroxyethyl imidazolium betaine, nonionic surfactants such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, sorbitan monostearate, and silicones whose main skeleton is polydimethylsiloxane Surfactants and the like. In the present invention, the surfactant is not limited to these, and one or more surfactants can be used.

In addition to the surfactant, a siloxane-based adhesion improver, a curing accelerator such as an aluminum chelate compound, and the like can be added. Above, the ink of the present invention,
And a method for forming a pixel using the same has been described. In order to produce a color filter, for example, a protective film is formed on the pixel obtained as described above, if necessary, and a transparent conductive film is further laminated thereon.

The following method can be used to manufacture a liquid crystal display device equipped with a color filter manufactured as described above. First, a liquid crystal alignment film is formed on a color filter, and a rubbing process is performed. Similarly, an alignment film is formed and combined with a counter substrate subjected to a rubbing treatment. Then, a liquid crystal is injected between the substrates to assemble the liquid crystal cell, whereby a color liquid crystal display device having the above color filter inside the liquid crystal cell is obtained.

Hereinafter, the present invention will be described specifically with reference to examples.

[0054]

EXAMPLES Example 1 Carbon black (manufactured by Mitsubishi Chemical Corporation, "MA100") 20
g in a polyamic acid solution ("Semico Fine" manufactured by Toray Industries, Inc.)
SP710) A black paste dispersed in 30 g was prepared, and a coating film was formed on a glass substrate by a spinner. The coating was dried at 100 ° C. for 20 minutes in a hot air oven so that the polyamic acid was not completely imidized. Further, a positive photoresist ("SRC100", manufactured by Shipley Far East Co., Ltd.) was applied on the upper surface and dried in a hot air oven at 90 ° C. for 10 minutes to form a positive photoresist layer having a thickness of 1.5 μm. After exposure through a mask, the development of the positive photoresist and the etching of the black paste coating film are simultaneously performed with an alkali developing solution, and the resist is stripped with a stripping solution.
After curing at 0 ° C. for 40 minutes, a 1 μm-thick resin black matrix was obtained.

Next, hydroxypropyl cellulose (manufactured by Nippon Soda) and a melamine resin (manufactured by Sumitomo Chemical Co., Ltd., “SUMITEX RESIN M”) were formed on the black matrix.
3 ”), a mixture of a curing agent (Sumitomo Chemical Co., Ltd.,“ Sumitex Accelerator ”ACX) is applied, and the mixture is placed in a hot air oven at 90
Prebaking was performed at 10 ° C. for 10 minutes to form an ink receiving layer having a thickness of 1.5 μm.

Subsequently, red, green, and blue inks having the following formulations were ink-jet-coated at predetermined locations to impregnate the ink-receiving layer. In these inks, since the soluble pigment precursor was completely dissolved and uniform, no coating defects occurred due to nozzle clogging or the like during the ejection process. Subsequently, the temperature was raised from 140 ° C. to 200 ° C. at a rate of 10 ° C./min in a hot air oven, followed by heating at 200 ° C. for 30 minutes to convert the soluble pigment precursor into an insoluble pigment and cure the resin layer. Then, a transparent conductive film was laminated by sputtering to obtain a color filter. The obtained color filter is
Since the pigment diameter in the colored layer was small, the contrast, color purity, and color transmittance were very high.

Further, a liquid crystal alignment film is formed on the obtained color filter, rubbed, and combined with a counter substrate that has been similarly rubbed, and then liquid crystal is injected between the substrates to assemble a liquid crystal cell. By performing the above, a color liquid crystal display device having the above color filter inside the liquid crystal cell was obtained. The obtained liquid crystal display device was excellent in display quality due to the high contrast, color purity, and color transmittance of the color filter. Also, light fastness,
The reliability such as weather resistance and heat resistance was satisfactory without any particular problem since the colorant was a pigment.

[Example of ink formulation] Ethylene glycol: 4
0 g, cyclopentanone: 17.5 g, water: 40 g, the following soluble pigment precursors: 2.5 g each (for R (red) ink: soluble pigment precursor of formula 4, for G (green) ink: formula 5) 1: 1 mixture of soluble pigment precursor of formula 6, for B (blue) ink: soluble pigment precursor of formula 6).

[0059]

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Embedded image Example 2 A black matrix was formed on a glass substrate in the same manner as in Example 1. Subsequently, red, green, and blue inks having the following formulations were inkjet-coated on the black matrix openings. In these inks, since the resin and the soluble pigment precursor were completely dissolved and uniform, no coating defects were caused by nozzle clogging or the like during the ejection process. Subsequently, in a hot air oven from 140 ° C to 200 ° C, 10 ° C /
Minutes, then heated at 200 ° C for 30 minutes,
A soluble pigment precursor was converted into an insoluble pigment and the resin layer was cured, and a transparent conductive film was further laminated on the upper layer by sputtering to obtain a color filter. The obtained color filter had a very high contrast, color purity, and color transmittance because the pigment diameter in the colored layer was small.

Further, a liquid crystal alignment film is formed on the obtained color filter, rubbed, and combined with a counter substrate which has been rubbed in the same manner. Then, liquid crystal is injected between the substrates to assemble a liquid crystal cell. By performing the above, a color liquid crystal display device having the above color filter inside the liquid crystal cell was obtained. The obtained liquid crystal display device was excellent in display quality due to the high contrast, color purity, and color transmittance of the color filter. Also, light fastness,
The reliability such as weather resistance and heat resistance was satisfactory without any particular problem since the colorant was a pigment.

[Example of ink formulation] Ethylene glycol: 3
5 g, cyclopentanone: 17.5 g, water: 34 g, water-soluble acrylic resin (manufactured by Johnson Polymer Co., "Johncryl" J-52): 7 g, melamine resin (Sumitomo Chemical Co., Ltd. "Sumitec Resin" M) -3): 4 g, the following soluble pigment precursor: 2.5 g each (for R (red) ink:
Soluble pigment precursor of formula 7, for G (green) ink: 1: 1 mixture of soluble pigment precursors of formula 8 and formula 9, for B (blue) ink: soluble pigment precursor of formula 9).

[0062]

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Embedded image Example 3 Carbon black (manufactured by Mitsubishi Chemical Corporation, "MA100") 20
g in a polyamic acid solution ("Semico Fine" manufactured by Toray Industries, Inc.)
SP710) A black paste dispersed in 30 g was prepared, and a coating film was formed on a glass substrate by a spinner. The coating was dried at 100 ° C. for 20 minutes in a hot air oven so that the polyamic acid was not completely imidized. Further, a positive photoresist ("SRC100", manufactured by Shipley Far East Co., Ltd.) to which a fluorine-based surfactant ("MEGAFAC" F-179, manufactured by Dainippon Ink and Chemicals, Inc.) was added, was applied on the upper portion thereof, and was heated at 90C in a hot air oven.
For 10 minutes to form a positive photoresist layer having a surface layer having a thickness of 1.5 μm and subjected to an ink-repellent treatment. After exposure through the mask, the development of the positive photoresist and the etching of the black paste coating film were simultaneously performed with an alkaline developer. Subsequently, the ink of Example 2 was ink-jet applied to the black matrix opening. At this time, in these inks, the soluble pigment precursor is completely dissolved and uniform, so that during the ejection process, coating defects such as color dropout and color mixing due to nozzle clogging do not occur, and furthermore, the black matrix is not used. Since the ink repelling fence is formed by the resist layer, the margin in the ink landing position accuracy is wide, and therefore, it is possible to reduce the ink landing position accuracy and perform high-speed coating. Subsequently, the ink was dried in a hot-air oven at 110 ° C. for 10 minutes, and the resist was stripped with a stripping solution.
Minutes, then heated at 200 ° C for 30 minutes,
The curing of the black matrix, the conversion of the soluble pigment precursor to an insoluble pigment, and the curing of the colored resin layer were simultaneously performed. Further, a transparent conductive film is laminated on the upper part by sputtering,
A color filter was obtained. The obtained color filter had a very high contrast, color purity, and color transmittance because the pigment diameter in the colored layer was small.

Further, a liquid crystal alignment film is formed on the obtained color filter, rubbed, and combined with a counter substrate that has been similarly rubbed, and then liquid crystal is injected between the substrates to assemble a liquid crystal cell. By performing the above, a color liquid crystal display device having the above color filter inside the liquid crystal cell was obtained. The obtained liquid crystal display device was excellent in display quality due to the high contrast, color purity, and color transmittance of the color filter. Also, light fastness,
The reliability such as weather resistance and heat resistance was satisfactory without any particular problem since the colorant was a pigment.

Comparative Example 1 A color filter was obtained in the same manner as in Example 1 except that the ink receiving layer was dyed with red, green, and blue dye inks of the following formulation. In these inks, dyes are completely dissolved and uniform, so no coating defects occur due to nozzle clogging, etc. during the ejection process, and the obtained color filter has contrast, color purity, and color transmittance. Example 1
The display quality was almost equivalent to that of No. 3, and the display quality when incorporated in the liquid crystal display device was excellent. However, since the coloring agent is a dye, the reliability of light resistance, weather resistance, heat resistance, and the like is poor.

[Example of ink formulation] Ethylene glycol: 2
0 g, isopropyl alcohol: 5 g, water: 72.5
g, the following dyes: 2.5 g each (for R (red) ink: C.I.
I. Mixed color of Acid Red 35 / Acid Yellow 23, for G (green) ink: C.I. I. Acid Blue 9
/ Acid Yellow 23 mixed color, for B (blue) ink:
C. I. Comparative Example 2 A color filter was prepared in the same manner as in Example 2 except that pixels were formed using red, green, and blue pigment inks dispersed with a homogenizer after mixing according to the following formulation. I got In these inks, the pigment was dispersed in the ink and was non-uniform, so that during the ejection process, nozzle clogging caused by the aggregation of the pigment was induced to cause coating defects. In addition, the obtained color filter has light resistance, since the colorant is a pigment,
Although the weather resistance and the heat resistance were excellent in reliability, the contrast,
The color purity and the color transmittance were inferior to those of Examples 1 to 3. Therefore, when incorporated in a liquid crystal display device, it could be used for a long time, but the display quality was inferior to those of Examples 1 to 3.

[Example of ink formulation] Ethylene glycol: 3
5 g, water: 51.5 g, water-soluble acrylic resin (manufactured by Johnson Polymer Co., Ltd., "Johncryl" J-52): 7 g,
Melamine resin (Sumitomo Chemical Co., Ltd. "Sumitec Resin" M-3): 4 g, the following pigment: 2.5 g each (for R (red) ink: a mixture of CI Pigment Red 177 / Pigment Yellow 139) For G (green) ink:
C. I. Pigment Green 36 / Pigment Yellow 139, for B (blue) ink: C.I. I. Pigment blue 15).

[0067]

The ink for producing a color filter according to the present invention has the above-mentioned constitution. Therefore, when a color filter is produced by an ink-jet method, there is no nozzle clogging, the ink ejection stability is excellent, and the contrast is high. It is possible to provide a color filter having high color purity, high transmission, and excellent reliability such as light resistance, weather resistance and heat resistance.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C056 FB01 FB08 FC02 2H048 BA29 BA64 BB02 4J039 AD10 AE03 BC16 BC50 BE01 BE12 EA15 EA16 EA17 EA20 GA16 GA24 GA34

Claims (14)

[Claims] An ink for producing a color filter, which is used for producing a color filter for forming pixels by discharging ink on a substrate by an ink-jet method, comprising at least a solvent and a soluble pigment precursor. 2. The ink for producing a color filter according to claim 1, wherein the soluble pigment precursor is a pigment which shows red, green or blue when it is converted into a pigment. 3. The ink for producing a color filter according to claim 1, wherein the soluble pigment precursor is a pigment which shows cyan, magenta or yellow when it is converted into a pigment. 4. The ink for producing a color filter according to claim 1, further comprising a resin. 5. The ink for producing a color filter according to claim 4, wherein said resin contains an acrylic resin. 6. The ink for producing a color filter according to claim 4, wherein said resin contains an acrylic resin and melamines. 7. The ink for producing a color filter according to claim 1, wherein said solvent contains at least N-methylpyrrolidone and / or cyclopentanone. 8. The ink for producing a color filter according to claim 1, wherein an ink mixing prevention fence is provided on the substrate. 9. The ink for producing a color filter according to claim 1, wherein a black matrix is provided on the substrate. 10. The ink for producing a color filter according to claim 9, wherein the black matrix has a constitution in which a light-shielding agent is contained in a resin. 11. A color filter using the ink for producing a color filter according to any one of claims 1 to 10. 12. A liquid crystal display device using the color filter according to claim 11. 13. The method according to claim 1, wherein the ink according to any one of claims 1 to 10 is ejected onto a substrate having an ink receiving layer formed thereon by an ink-jet method, soaked, and then a soluble pigment precursor is converted into an insoluble pigment. A method for producing a color filter, characterized in that it is formed. 14. A method for forming a pixel by discharging the ink for producing a color filter according to claim 4 onto a substrate by an ink jet method, fixing the ink by curing the resin, and converting the soluble pigment precursor into an insoluble pigment. A method for producing a color filter, comprising: