JPH0635188A - Photopolymerizable composition for color filter and color filter - Google Patents

Abstract

PURPOSE:To produce a pigment compsn. for a color filter contg. carbon black, having satisfactory resolution and high sensitivity and ensuring a simple process and excellent economical efficiency at the time of forming a black matrix. CONSTITUTION:This photopolymerizable compsn. consists of a photopolymerizable compd. having one or more ethylenic unsatd. double bonds, a photopolymn. initiator, a photosensitive resin and carbon black having <=100m<2>/g BET specific surface area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter composition and a color filter. More specifically, the present invention relates to a photopolymerizable composition for color filters having excellent optical properties used for liquid crystal display devices and the like, and a color filter obtained from the photopolymerizable composition.

[0002]

2. Description of the Related Art Color filters used in color liquid crystal display devices and the like, which are being converted from the CRT system, are
A fine pixel colored in at least two kinds of hues and a black matrix are formed between the pixels for the purpose of blocking light. This black matrix is used to improve the contrast of the displayed image,
It is used in TFT drive type liquid crystal displays, which have been actively researched and developed in recent years, in order to prevent malfunction of the TFT due to light.

The black matrix as described above is usually formed of a metal thin film having a fine pattern on a glass substrate, and specific examples thereof include a film of Cr, Ni, Al or the like. Is a vapor deposition method, a sputtering method,
The vacuum film forming method is generally used.

Generally, a black matrix is formed by photolithography using the above metal thin film. Specifically, a photoresist is applied on a metal thin film, dried, and then irradiated with ultraviolet rays through a photomask to form a resist pattern, followed by etching and resist stripping. However, the black matrix manufactured as described above has a problem in that the manufacturing cost is high due to the complexity of the process, and the cost of the color filter using the black matrix is also high.

Further, when a color filter using this metal thin film is mounted on a transmissive display, the metal surface generally used as the metal thin film has a high reflectance, so that when strong external light hits the filter, for example, a Cr thin film is used. In the case of 1, the reflected light is strong, and there is a problem that the display image quality is significantly deteriorated. On the other hand, various methods have been studied in order to improve the above problems of the black matrix using the metal thin film. Japanese Patent Application Laid-Open No. 2-239204 proposes a method of forming a black matrix by dispersing a light shielding material such as carbon black in a polyimide resin and using the light shielding material. According to this method, a highly reliable black matrix can be obtained because the external light reflection is small and the heat resistance of the polyimide resin of the base material is high. However, this method is disclosed in the above-mentioned JP-A-2-239.
After coating the composition described in 204 on a substrate and drying,
Further, apply a photoresist on it, pattern it,
Since the steps of etching and resist stripping are performed, it is insufficient in terms of simplification of steps and cost reduction.

[0006] Various methods for forming a black matrix by dye-added photolithography in which an image is formed with a photopolymerization initiator using a photopolymerizable compound having an ethylenically unsaturated double bond have also been reported.

On the other hand, as the black pigment internally added, carbon black or a mixture of other organic pigments is used, but it is necessary to use a carbon rack in order to obtain a sufficient light-shielding property. However, since carbon racks trap radicals generated from a photopolymerization initiator by ultraviolet light, it inhibits photopolymerization, and it is difficult to form a sufficient image with an economical exposure amount. There was a problem with sex.

[0008]

It is desired to develop a photopolymerizable composition for a color filter, which has a simple process for forming a black matrix, is excellent in economic efficiency, and has good resolution.

[0009]

The present inventors have made diligent efforts to find a method for producing a color filter which is simple in the above-mentioned steps, excellent in economical efficiency and good in resolution, and as a result, a specific light is obtained. The present invention has been completed by finding that the polymerization composition satisfies the above characteristics.

That is, the present invention provides (1) a photosensitive resin containing a photopolymerizable compound having at least one ethylenically unsaturated double bond, a photopolymerization initiator, and optionally other resins, and carbon black. A photopolymerizable composition for a color filter, which is a composition contained as a main component, wherein the specific surface area of the carbon black is 100 [BET-m ² / g] or less (2) The surface of the carbon black is The previous item (1) that is acidic
Photopolymerizable composition for color filter according to (3) The photopolymerizable composition for color filter according to (1) or (2) above, wherein the photosensitive resin is a photosensitive resin containing 60% or more of a photopolymerizable compound. (4) The photopolymerizable composition for a color filter according to the above (1) to (3), wherein the photosensitive resin is a photopolymerizable compound having an average molecular weight of 1000 or more. (5) The photopolymerization initiator is represented by the following formula: (1)

[0011]

[Chemical 2]

The photopolymerizable composition for a color filter as described in the above items (1) to (4), which is a mixture of the compound represented by the formula (1), a thioxanthone compound and optionally other photopolymerization initiators (6) Others The photopolymerization composition for a color filter according to the above item (5), wherein the photopolymerization initiator is a mixture of a hexaarylbisimidazole compound and a hydrogen donor. (7) The hydrogen donor is an aromatic mercaptan. (8) The photopolymerizable composition for a color filter according to (8), wherein the hydrogen donor is an aromatic amine, the photopolymerizable composition for a color filter according to the above (6), (9) The hydrogen donor is 2-mercaptobenzothiazole or The photopolymerizable composition for a color filter according to item (6), which is 2-mercaptobenzoxazole (10) The color filter according to items (1) to (9). Providing a color filter manufactured using the coater for photopolymerizable compositions.

The photopolymerizable composition for a color filter and the color filter of the present invention will be described in detail.

Since the photopolymerizable composition for a color filter of the present invention contains carbon black, it may absorb the ultraviolet rays necessary for photopolymerization, so that the photopolymerizable composition with high sensitivity is obtained. It is preferable to use a compound, and in order to carry out photopolymerization efficiently, the ratio of the photopolymerizable compound in the photosensitive resin (consisting of the photopolymerizable compound, the photopolymerization initiator and, in some cases, other resin) is 60%.
It is preferable to prepare the photosensitive resin composition as described above. Examples of the photopolymerizable compound having at least one ethylenically unsaturated double bond that can be used include the following compounds.

As photocrosslinkable or photopolymerizable monomers, oligomers and prepolymers, ethyl acrylate, butyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, ethylene glycol dimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, dipenta. Acrylic or methacrylic acid esters of monohydric or polyhydric alcohols such as erythritol hexaacrylate, dipentaerythritol hexamethacrylate; polyester prepolymers obtained by condensing polyhydric alcohols with monobasic acids or polybasic acids Polyester (meth) acrylate obtained by reacting (meth) acrylic acid; after reacting a compound having a polyol group and two isocyanate groups Meth) polyurethane obtained by reacting acrylic acid (meth) acrylate; bisphenol A type epoxy resin, bisphenol F type epoxy resin,
Epoxy resin such as novolac type epoxy resin, polycarboxylic acid glycidyl ester, polyol polyglycidyl ester, aliphatic or alicyclic epoxy resin, amine epoxy resin, triphenolmethane type epoxy resin, dihydroxybenzene type epoxy resin and (meth) acrylic Typical photopolymerizable resins such as epoxy (meth) acrylate obtained by reacting an acid are mentioned.

Among these photopolymerizable compounds, compounds having an average molecular weight of 1,000 or more have a very high photopolymerization rate, and it is particularly useful to incorporate these compounds in the photosensitive resin composition.

In the present invention, a photopolymerizable compound having an acidic group such as a carboxyl group and an ethylenically unsaturated double bond is particularly preferably used. These compounds are extremely useful in increasing the content ratio of the photopolymerizable compound having an ethylenically unsaturated double bond in the photosensitive resin to increase the polymerization rate when exposed to the atmosphere, and at the same time to enable aqueous development. . Specific examples of such a photopolymerizable compound having an acidic group such as a carboxyl group and an ethylenically unsaturated double bond are:

Bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, polycarboxylic acid glycidyl ester, polyol polyglycidyl ester, aliphatic or alicyclic epoxy resin, amine epoxy resin, triphenolmethane type epoxy resin Epoxy (meth) obtained by reacting an acid anhydride with a hydroxy group obtained by reacting (meth) acrylic acid with an epoxy group such as dihydroxybenzene type epoxy resin
Acrylate-carboxylic acid adducts Hydroxyethyl at the maleic anhydride part of the copolymer with monomers such as ethylene, propene, isobutylene, styrene, vinylphenol, acrylic acid, acrylic acid ester and acrylamide, which are copolymerizable with maleic anhydride. Compounds obtained by reacting acrylates with alcoholic hydroxy groups such as acrylates and acrylates with epoxy groups such as glycidylmethacrylate into half-esterified acrylic acid, acrylate esters and acrylates with alcoholic hydroxy groups such as hydroxyethyl acrylate Examples thereof include compounds obtained by further reacting acrylic acid with -OH groups of the copolymer.

These compounds may be used alone or as a mixture, and the total weight thereof is 60 in the photosensitive resin.
It is preferable to use it in such a proportion that it occupies at least%.

Other resins that can be contained in the photosensitive resin include film-forming polymer binders. As the film-forming polymer binder, any organic polymer binder compatible with the photopolymerizable resin can be used, and examples thereof include polymethacrylic acid ester or its partial hydrolyzate and polyacetic acid. Vinyl or its hydrolysis, polystyrene, polyvinyl butyral, polychloroprene, polyvinyl chloride, chlorinated polyethylene, chlorinated polypropylene, polyvinylpyrrolidone, a copolymer of styrene and maleic anhydride or its half ester, acrylic acid, acrylic ester, A copolymer having a glass transition point of 35 ° C. or higher selected from the group of copolymerizable monomers such as methacrylic acid, methacrylic acid ester, acrylamide, and acrylonitrile is used. Among these, those having an acidic group such as a carboxyl group are advantageous in that they enable aqueous development, which is advantageous in terms of economy and safety, as compared with organic solvent development. The film-forming polymer binder as described above is preferably used within the range of 40% or less by weight in the photosensitive resin.

In the present invention, an epoxy compound or the like can be used as another resin for the purpose of improving heat resistance. The epoxy compound is useful for improving heat resistance by thermally reacting with the compound having a carboxylic acid and crosslinking.

Specific examples of such an epoxy compound include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, polycarboxylic acid glycidyl ester, polyol polyglycidyl ester, aliphatic or alicyclic epoxy resin. Resin, amine epoxy resin, triphenol methane type epoxy resin,
Examples thereof include dihydroxybenzene type epoxy resin. These compounds are added to the photosensitive resin in an amount of 20% by weight.
% Or less, preferably 5 to 10%, if necessary.

As the photopolymerization initiator used in the present invention, various photopolymerization initiators can be used alone or in combination, but generally, a colored photopolymerizable resin in which a pigment is dispersed in a photopolymerizable resin is used. In the case, since the pigment absorbs the ultraviolet rays necessary for the photopolymerization initiator to generate radicals and sufficient radicals cannot be generated, the polymerization tends to be insufficient.

Therefore, a highly sensitive compound or composition is required as the photopolymerization initiator for the pigment-containing photosensitive resin. Specific examples of the photopolymerization initiator that can be used include benzyl; benzoin ether; benzoin isobutyl ether; benzoin isopropyl ether; benzophenone; benzoylbenzoic acid; methyl benzoylbenzoate;
4-benzoyl-4′-methyldiphenyl sulfide; benzyl methyl ketal; 2-n-butoxyethyl-4-methylaminobenzoate; 2┘chlorothioxanthone; 2,4-diethylthioxanthone; 2,4-
Diisopropylthioxanthone; Dimethylaminomethylbenzoate; Isoamyl p-dimethylaminobenzoate;
3,3'-dimethyl-4-methoxybenzophenone;
2,4┘Dimethylthioxanthone; 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropane-1
-One; 1-hydroxycyclohexyl phenyl ketone; 2-hydroxy-2-methyl-1-phenylpropan-1-one; 1- (4-isopropylphenyl) -2
-Hydroxy-2-methylpropan-1-one; isopropylthioxanthone; methylobenzoyl formate; 2-methyl-1- [4- (methylthio) phenyl]
A photopolymerization initiator such as 2-morpholinopropan-1-one; 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one is used. These photopolymerization initiators can be used alone or in combination of two or more.

In the present invention, a preferable mixture of photopolymerization initiators is 2-benzyl-2-dimethylamino-
There is a mixture of 1- (4-morpholinophenyl) -butan-1-one (formula (1)) and a thioxanthone compound.

Specific examples of the thioxanthone compounds which can be used with such a mixture include the above-mentioned 2-chlorothioxanthone, 2,4┘dimethylthioxanthone and 2,4-.
Diethyl thioxanthone, 2, -diisopropyl thioxanthone, isopropyl thioxanthone, etc. are mentioned. Also, 2-benzyl-2-dimethylamino-1-
A hexaarylbisimidazole compound, a hydrogen donor and the like may be further added to the mixture of (4-morpholinophenyl) -butan-1-one (formula (1)) and the thioxanthone compound.

As examples of the hexaarylbisimidazole compound, those disclosed in US Pat. No. 3,784,557, European Patent A24629 and the like can be used. However, they are particularly preferable in terms of stability and sensitivity,
2,2'-bis (o-chlorophenyl) -4,4 ',
5,5'-Tetraphenylbisimidazolyl; 2,2 '
-Bis (o-chlorophenyl) -4,4 ', 5,5'-
And tetra- (p-methoxyphenyl) bisimidazolyl.

As the hydrogen donor, aromatic mercaptan compounds and aromatic amine compounds are used. Among these, as the aromatic mercaptan hydrogen donor, a compound having one or two mercapto groups with benzene or a heterocycle as a mother nucleus is preferable.
One of the mercapto groups may be substituted with alkyl, aralkyl, or phenyl, or may be a dimer in the form of disulfide.

2-Mercaptobenzothiazole, 2-mercaptobenzoxazole and the like are particularly preferable.

As the aromatic amine hydrogen donor, a compound having benzene or a heterocycle as a nucleus and having one or two amino groups is preferable, and the amino group is an alkyl group,
Alternatively, it may be substituted with a substituted alkyl group, and the monoamino compound may be further substituted with a carboxyl group, an alkoxycarbonyl group, a substituted alkoxycarbonyl group, a phenoxycarbonyl group, a substituted phenoxycarbonyl group, a nitrile group or the like. As a particularly preferred example,

[0031]

[Chemical 3]

And the like. The total amount of these photopolymerization initiators or a mixture thereof used for the photosensitive resin is 0.1.
10 to 10% by weight, preferably 0.5 to 5% by weight.

It is difficult for a radical polymerization resin containing a normal carbon black to complete the polymerization due to the effect of inhibiting the polymerization of carbon black. Has insufficient adhesion to the substrate, resulting in problems such as peeling of pixels during development, resolution, and elution of carbon black solvent from the cured film. In the present invention,
In order to solve the above problems, a specific carbon black is used. That is, the carbon black used in the present invention has a specific surface area of 100 [BET-m ² / g] or less, and more preferably, its surface is acidic. Specific examples of such carbon black include the following carbon blacks.

Printex 4 (manufactured by Degussa)
5, Printex40, Printex300, Pr
index30, Printex3, Printex3
5, Printex25, Printex200, Pr
intexA, PrintexG, SpecialBa
ck350, SpecialBack250 Spec
ialBack100 (manufactured by CABOT) MONARCH 460, MONAR
CK430, MONARCK280, MONARCK1
20, REGAL330, REGAL415, REGA
L250, REGAL99, BLACK PEARLS
480, BLACK PEARLS130 (manufactured by Columbian Carbon) Raven
1060, Raven1040, Raven1035,
Raven1020, Raven1000, Raven
890H, Raven890, Raven850, Ra
ven790, Raven780, Raven760,
Raven500, Raven450, Raven43
0, Raven420, Raven410

The carbon black as described above may be used in combination with other organic pigments depending on the case, and the mixing ratio of the carbon black and the organic pigment is arbitrary, but the light-shielding property of the organic pigment is lower than that of the carbon black. , It is desirable to use an organic pigment in a range that does not impair the light-shielding property of the film by the photopolymerizable composition for a color filter produced by using these, and the total weight of carbon black and other organic pigments may be the photosensitive resin. To 10 to 50% by weight.

Carbon black as described above, and optionally other organic pigments, together with a dispersant and a solvent,
It is dispersed with a disperser such as a sand mill or a triple roll. As the dispersant used at this time, those usually used for dispersing pigments can be used. As described above, the photosensitive resin composed of the photopolymerizable compound and the photopolymerization initiator and other resins in some cases, and the pigment dispersion paste composed of the carbon black containing other organic pigments in some cases, the dispersant, and the solvent, The photopolymerizable composition for a color filter is prepared by mixing the above components in an ordinary mixer.

At this time, it is desirable that the photopolymerizable composition for the color filter is diluted with an organic solvent to an appropriate viscosity in a coating machine as described later. Specific examples of the organic solvent include ethyl cellosolve acetate and butyl cellosolve. Acetate, isopropyl cellosolve acetate, methoxy isopropyl glycol acetate, ethoxy isopropyl glycol acetate, diglyme, etc., are not limited thereto. The photopolymerizable composition for a color filter obtained as described above is preferably filtered for the purpose of removing foreign matters in the system, and the filtering is carried out using a usual filter.

The photopolymerizable composition for color filters of the present invention is applied to a substrate such as glass by a spinner or the like,
Further drying of the solvent gives a smooth coating film.
In order to form a desired image on this coating film, ultraviolet rays are irradiated through a negative mask. At this time, a device such as a mask alignment is used so that the parallel rays are uniformly applied to the entire coating film. Next, the irradiated coating film is heated for a short time to accelerate polymerization, and then exposed to running water of a developing solution or in a shower to dissolve the uncured portion and develop the desired image (color filter). Is obtained.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Preparation Example of Photosensitive Resin 4 g of the compound represented by the following formula (A), 3 g of the compound represented by the following formula (B), 3 g of dipentaerythritol hexaacrylate, and Irgacure 369 manufactured by Ciba-Geigy 0.4 g of (photopolymerization initiator), Kayakyu DETX (photopolymerization initiator) manufactured by Nippon Kayaku, 0.1 g of lophine dimer, 0.1 g of 2-mercaptobenzothiazole, and ethyl cellosolve. 2 acetate
0 g was mixed.

[0041]

[Chemical 4]

[0042]

[Chemical 5]

Dispersion Example 1 Degussa carbon black Special B
rack350 "specific surface area 65 [BET- (m ² /
g)], pH 3 "15 g, sorbitan fatty acid ester-based dispersant 3 g, ethyl cellosolve acetate 82 g,
It was dispersed in a sand mill for 3 hours.

Dispersion Examples 2 to 9 Using the carbon blacks shown in Table 1, dispersion was carried out in the same manner as in Dispersion Example 1. The specific surface area is [BET- (m ² /
g)].

Table 1 (manufactured by Degussa) Specific surface area pH Dispersion example 2 Printex 140v 90 4.0 Dispersion example 3 Printex 25 45 9.5 Dispersion example 4 SpecialBlack100 30 3.0 (manufactured by CABOT) Dispersion example 5 REGAL400R 96 4.0 Dispersion Example 6 MONARCH 460 80 8.0 (manufactured by Columbian Carbon) Dispersion Example 6 Raven 1060 28 2.4 Dispersion Example 7 Raven 890H 95 6.0 Dispersion Example 8 Raven 760 65 Dispersion 7.4 Example 9 Raven 1035 95 3.5

Example 1 Dispersion Example 1 was added to the photosensitive resin obtained in Preparation Example of Photosensitive Resin.
10 g of the dispersion paste obtained in step 1 was added and mixed with stirring. Then, the photopolymerizable composition for color filter was applied to a 7059 glass substrate manufactured by Corning Co., Ltd. with a spinner so as to have a film thickness of 1.5 μm and dried. 2 to this
After exposing 100 mj with an ultra-high pressure mercury lamp through a photomask having a line and space of 0 μ, it was exposed to 30% with a 1.0% tetramethylammonium hydroxide aqueous solution.
Second shower development, washing with water and baking at 200 degrees,
A color filter with good resolution could be produced.

Examples 2 to 9 A photopolymerizable composition for a color filter was prepared using the dispersion pastes of Examples 2 to 9 in the same manner as in Example 1, and then a color filter was prepared. Pixels could be made.

Comparative Example The same procedure as in Example 1 was repeated except that the same procedure as in Dispersion Example 1 was applied to the photosensitive resin obtained in Preparative Example for Preparation of Photosensitive Resin. Carbon black Raven 5000 "specific surface area 430 [B
ET- (m ^{2 /} g)], pH 2.8 ”was used to prepare a photopolymerizable composition for a color filter, and then a color filter was prepared under the same conditions as in Example 1. Sometimes the pixels came off.

Further, even when a color filter was produced in the same manner with an exposure amount of 500 mj, pixels were peeled off during development.

[0050]

INDUSTRIAL APPLICABILITY Using carbon black, a photopolymerizable composition for a color filter and a color filter having a simple manufacturing process, high resolution and high sensitivity can be produced.

Claims (10)

[Claims] 1. At least one ethylenically unsaturated double bond.
A photosensitive resin containing one or more photopolymerizable compounds, a photopolymerization initiator, and optionally other resins, and carbon black as main components, wherein the specific surface area of the carbon black is 100 [BET- m ² /
g] A photopolymerizable composition for a color filter, which is: 2. The photopolymerizable composition for a color filter according to claim 1, wherein the surface of the carbon black is acidic. 3. The photopolymerizable composition for a color filter according to claim 1, wherein the photosensitive resin is a photosensitive resin containing 60% or more of a photopolymerizable compound. 4. The photopolymerizable composition for a color filter according to claim 1, wherein the photosensitive resin is a photopolymerizable compound having an average molecular weight of 1000 or more. 5. A photopolymerization initiator is represented by the following general formula (1): The photopolymerizable composition for a color filter according to any one of claims 1 to 4, which is a mixture of the compound represented by the formula (1), a thioxanthone compound, and optionally another photopolymerization initiator. 6. The photopolymerizable composition for a color filter according to claim 5, wherein the other photopolymerization initiator is a mixture of a hexaarylbisimidazole compound and a hydrogen donor. 7. The photopolymerizable composition for a color filter according to claim 6, wherein the hydrogen donor is an aromatic mercaptan. 8. The hydrogen donor is an aromatic amine.
The photopolymerizable composition for a color filter according to item 1. 9. The photopolymerizable composition for a color filter according to claim 6, wherein the hydrogen donor is 2-mercaptobenzothiazole or 2-mercaptobenzoxazole. 10. A color filter produced by using the photopolymerizable composition for a color filter according to claim 1.