JPH10260526A - Black photosensitive resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a black photosensitive resin composition having sufficient density for shielding light, capable of forming a black matrix low in reflectance and enhanced in adhesion between the black matrix and a glass plate by adding a polymer compound having specified alkyl groups on the side chains to a resin type material. SOLUTION: This black photosensitive resin composition comprises the 20-45 weight% resin type material, a 5-20 weight% cross-linking agent, 2-15 weight% acid-photo-generator, an a 20-60 weight% black pigment. The polymer compound having the 3-12C alkyl groups on the side chains is added to the resin type material in an amount of 5-80 weight%. As the resin type material, a polymer material having OH groups capable of becoming cross-linking points and soluble in an aqueous solution of alkali is preferable, and if the C number of the alkyl groups on the side chains is <=2, adhesion is made insufficient and undesirable and if >=13, flexibility is made unfavorably low.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a black photosensitive resin composition, and more particularly to a black resin composition used for a black matrix of a color filter used for a liquid crystal display or the like.

[0002]

2. Description of the Related Art Conventionally, when a color filter is formed into a liquid crystal panel, a black photosensitive resin is used on the outer periphery of the color filter pattern to prevent leakage of backlight light from the outer periphery of the panel. A frame-like pattern of about 5 mm is formed. Further, an epoxy-based adhesive is applied to the frame-shaped pattern to bond it to the counter substrate. However, since the adhesion between the black resin and the glass substrate is weak, the black resin may be separated from the glass interface.

A color filter widely used in a liquid crystal display device or the like has a plurality of pixels of a plurality of colors such as red, green, and blue arranged on a transparent substrate. A black matrix is formed therebetween. The black matrix is also used for the purpose of preventing a malfunction of a transistor used for a TFT-driven liquid crystal display.

Usually, the above-mentioned black matrix is often formed of a metal thin film having a fine pattern on a glass substrate. For example, a general method is to form a thin film of a metal or a metal compound such as chromium, nickel, or aluminum by a vacuum film forming method such as an evaporation method or a sputtering method, and then form a fine pattern by a photolithography method. . More specifically, a photoresist is applied on a thin film of metal or the like,
After drying, irradiation with ultraviolet rays through a photomask and development are performed to form a resist pattern, and then a black matrix is formed through an etching step and a resist peeling step. However, the manufacturing cost of the black matrix manufactured in the above process is very high due to the complexity of the process, and the cost of the color filter using the black matrix is also high. In addition, since the surface of a metal generally used as a metal thin film (for example, a chromium thin film) has a high reflectance, a liquid crystal display of a transmission type has
When a color filter using this metal thin film is mounted,
When strong external light is incident on the color filter, there is a problem that the display quality is significantly reduced.

Therefore, various methods have been studied in order to improve the problem of the black matrix using such a metal thin film. For example, there has been proposed a method of dispersing a black pigment and an organic pigment as needed in a photosensitive resin composition, and forming a black matrix using the dispersion. If the black photosensitive resin composition is used, since the reflectance of the surface is low, the display quality is not significantly reduced,
In addition, since the manufacturing process can be simplified, costs can be reduced. However, in order to obtain a sufficient light-shielding property only with a black pigment, a thick film thickness of about 1 μm or more is required. Therefore, a so-called one-shape is formed in an overlapping portion with a plurality of color pixels which is a margin for alignment. Protrusions occur,
This caused display unevenness.

Japanese Unexamined Patent Publication No. Hei 6-59119 discloses a method in which a black photosensitive resin layer is provided on a plurality of color pixels and in a gap, and then the entire color is exposed from the substrate side using the plurality of color pixels as a mask. Methods and materials for selectively providing a black matrix only in the gap between pixels have been proposed. When this so-called back exposure method is used, there is an advantage that a single protrusion does not occur.

[0007]

However, in order to make the thickness of the black black matrix sufficient and to prevent the black layer from remaining on the multi-color pixels, the multi-color pixels used as the mask must be A sufficiently high light-shielding property in the photosensitive wavelength region of the black photosensitive resin composition was required. In particular, in the case of a black photosensitive resin, the photosensitive characteristic curve is relatively gentle and the γ value is small, so that a sufficiently large exposure amount (about 150 to 200 mJ /
cm ² ), and accordingly, a higher light-shielding property is required for the multi-color pixels. Therefore, an ultraviolet absorber or a fluorescent whitening agent such as titanium oxide, zinc oxide, a benzotriazole-based compound, or a coumarin-based compound must be added to the multi-color pixels serving as a mask. However, there is a problem that the addition of such an ultraviolet absorber impairs the optical characteristics of the color filter of the plurality of color pixels, that is, the transparency and the contrast ratio.

Further, in the black photosensitive resin composition, the photopolymerization initiator contained therein crosslinks due to radicals generated by ultraviolet irradiation, and the black pigment captures the radicals. Has the property of
Photopolymerization is hindered, and the crosslinking reaction tends to be insufficient at an economical exposure dose, and the pattern may peel off during development, making it difficult to form a good pixel.
The present invention has been made to solve such a problem, and has a sufficient density to block light, can form a black matrix having a low reflectance, and can adhere to a black matrix and a glass substrate. An object of the present invention is to provide a black photosensitive resin composition capable of producing a color filter having high film strength and improved film strength.

[0009]

The black photosensitive resin composition of the present invention comprises 20 to 45% by weight of a resinous material and 5 to 2% of a crosslinking agent.
0% by weight, 2 to 15% by weight of photoacid generator, 20 to black pigment
In a black photosensitive resin composition containing 60% by weight,
A polymer compound having an alkyl group having 3 to 12 carbon atoms in a side chain is added to the resin-based material in an amount of 5 to 80% by weight. Further, as the resin-based material, a polymer compound containing an OH group that can be a cross-linking point and soluble in an aqueous alkali solution is preferable.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The black photosensitive resin composition of the present invention which can be used for a black matrix comprises a resin material, a polymer compound having an alkyl group having 3 to 12 carbon atoms in a side chain, and a crosslinking agent. , A photoacid generator and a black pigment. For resin-based materials, O
A polymer compound containing an H group and soluble in an aqueous alkaline solution is applied. As the resin-based material, phenols such as phenol novolak and p-hydroxystyrene, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, OH groups such as acrylic acid, methacrylic acid, maleic acid, and fumaric acid are used. A homopolymer or a copolymer of the contained monomers is used. Other monomers that can be used for copolymerization include styrene, phenylmaleimide, methyl acrylate, ethyl acrylate, butyl acrylate, benzyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, benzyl methacrylate, and the like. Can be In the heat treatment in the presence of the acid generated by the exposure, a dehydration crosslinking reaction occurs between the portion of the crosslinking agent having the N-methylol structure and the portion having the OH group structure. As a result, the crosslink density between the resins is increased by the crosslinking between the resins, and the chemical resistance of the formed pattern is significantly improved. These resin materials are used in the range of 20 to 45% by weight, more preferably 25 to 35% by weight. If the amount is too small, problems such as deterioration of the photosensitive function, deterioration of the pattern shape due to the aggregation of carbon, and insufficient film strength and adhesion may occur.

In the present invention, a high molecular compound having an alkyl group having 3 to 12 carbon atoms in a side chain is essential. Such high molecular compounds include isobutyl acrylate,
t-butyl acrylate, lauryl acrylate, cyclohexyl acrylate, benzyl acrylate, 2-
Examples include ethylhexyl acrylate, butoxytriethylene glycol acrylate, and 2-ethylhexyl methacrylate. The carbon number of the side chain alkyl group is 3
To 12, more preferably 4 to 8 carbon atoms. When the number of carbon atoms is 2 or less, the adhesion becomes insufficient, which is not preferable. When it is 13 or more, the flexibility is lowered, which is not preferable. The polymer compound having the alkyl group in the side chain is used in an amount of 5 to 80% by weight, preferably 10 to 30% by weight, based on the resin material described above. If the amount is too small, the flexibility of the black matrix itself cannot be obtained and the adhesion becomes insufficient. If the amount is too large, the flexibility increases too much and peels off during alkali development.

Examples of the crosslinking agent include methylolated urea, urea resin, methylolated melamine, butyrolated melamine,
It is possible to use methylolated guanamine or an alkyl ether of these compounds. Alkyl ethers are more preferred because of their excellent thermal stability.
The alkyl group of the alkyl ether has 1 to 1 carbon atoms.
5 alkyl groups are preferred. In particular, as this alkyl ether compound, an alkyl ether compound of hexamethylolmelamine, which is excellent in sensitivity, is more preferable. Further, a compound having two or more epoxy groups can also be used. These crosslinking agents are used in the range of 5 to 20% by weight. If the amount is too small, the photosensitive characteristics are hindered. If the amount is too large, the light-shielding properties are insufficient.

As the photoacid generator, there can be used a trihalomethyl group-containing triazine derivative or an onium salt which has an absorption in a wavelength range included in light emission of a light source and generates an acid by light absorption. In particular, a trihalomethyl group-containing triazine derivative is preferable in terms of increasing sensitivity. Trihalomethyl group-containing triazine derivatives include 2,4,6
-Tris (trichloromethyl) -s-triazine, 2-
(P-methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2-piperonyl-4,6-bis (trichloro Methyl) -s-triazine, 2- (p-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (p-chlorophenyl) -4,6bis (trichloromethyl) -s
-Triazine, 2- (4'-methoxy-1'-naphthyl)
Examples thereof include -4,6-bis (trichloromethyl) -s-triazine and 2- (p-methylthiophenyl) -4,6-bis (trichloromethyl) -s-triazine.

Examples of the onium salts include diphenyliodonium tetrafluoroborate, diphenyliodonium hexafluorophosphonate, diphenyliodonium hexafluoroarsenate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium trifluoroacetate, diphenyliodonium-p-toluenesulfonate, -Methoxyphenylphenyliodonium tetrafluoroborate, 4-methoxyphenylphenyliodonium hexafluorophosphonate, 4-methoxyphenylphenyliodonium hexafluoroarsenate, 4-methoxyphenylphenyliodonium trifluoromethanesulfonate, 4-methoxyphenylphenyliodonium trifluoroacetate , - methoxyphenyl iodonium -p- toluenesulfonate, bis (4-tert- butylphenyl) iodonium tetrafluoroborate, bis (4-tert- butylphenyl) iodonium hexafluorophosphonate, bis (4-tert- butylphenyl)
Iodonium hexafluoroarsenate, bis (4-
tert-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-tert-butylphenyl) iodonium trifluoroacetate, bis (4-tert-
Butylphenyl) diaryliodonium salts such as iodonium-p-toluenesulfonate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluorophosphonate, triphenylsulfonium hexafluoroarsenate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium triphenyl Fluoroacetate, triphenylsulfonium-p-toluenesulfonate, 4-methoxyphenyldiphenylsulfonium tetrafluoroborate, 4-methoxyphenyldiphenylsulfonium hexafluorophosphonate, 4-methoxyphenyldiphenylsulfonium hexafluoroarsenate, 4
-Methoxyphenyldiphenylsulfonium trifluoromethanesulfonate, 4-methoxyphenyldiphenylsulfonium trifluoroacetate, 4-methoxyphenyldiphenylsulfonium-p-trienesulfonate, 4-phenylthiophenyldiphenyltetrafluoroborate, 4-phenylthiophenyldiphenylhexa Fluorophosphonate, 4-phenylthiophenyldiphenylhexafluoroarsenate, 4-phenylthiophenyldiphenyltrifluoromethanesulfonate, 4-phenylthiophenyldiphenyltrifluoroacetate, 4-phenylthiophenyldiphenyl-
Trial sulfonium salts such as p-toluene sulfonate and 4-hydroxynaphthyl sulfonium trifluoromethane sulfonate are exemplified.

These photoacid generators are used in the range of 2 to 15% by weight. If added in excess of 15% by weight, the amount of acid generated is too large and the acid diffuses into unexposed areas due to heating after pattern exposure, causing a cross-linking reaction and causing a reduction in resolution. On the other hand, when the amount is less than 2% by weight, the amount of generated acid is insufficient, the crosslinking reaction does not proceed sufficiently, and a pattern cannot be formed.

As the black pigment, a mixture of carbon black, titanium oxide, iron black, aniline black and an organic pigment can be used. If necessary, an acrylic resin as a dispersion medium for improving the dispersibility of the pigment, It is also possible to add an epoxy resin or the like. Further, a polymer dispersant, a derivative of an organic dye, or the like may be added as a dispersant. Further, a polymer-grafted carbon black grafted with a polymer compound may be used. These black pigments are used in the range of 20 to 60% by weight, preferably 40 to 50% by weight. If the amount is too small, sufficient light-shielding properties cannot be obtained, and if it is too large, the function as a photosensitive resin cannot be maintained.

The black photosensitive resin composition of the present invention can be obtained by kneading these materials using a disperser such as a two-roll mill, a three-roll mill, a sand mill, and a paint conditioner. As a diluting solvent to further improve the workability at the time of dispersion, ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, butyl cellosolve acetate, ethyl carbitol, ethyl carbitol acetate, diethylene glycol, cyclohexanone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, Organic solvents such as lactic acid esters may be used.

An example of forming a black matrix of a color filter using the black photosensitive resin composition of the present invention will be described. First, as shown in FIG. 2, a spinner method, a bar coat method, a roll coat method, The black photosensitive resin composition is uniformly applied using a curtain coating method or the like, and the black resin layer 3 made of the black photosensitive resin composition is formed on the gaps 4 between the plurality of color pixels 2 and on the plurality of color pixels 2. I do. As a method for forming the multi-color pixels 2, a method currently in practical use, such as a well-known dyeing method, a pigment dispersion method, a printing method, and an electrodeposition method may be used. Further, in order to make the black resin layer 3 and the transparent substrate 1 more closely contact each other, 70 ° C.
Heat of about 100 ° C. may be applied.

Next, ultraviolet light is irradiated from the back surface of the transparent substrate 1 (the lower part in FIG. 2) to perform exposure, so that acid is generated only in the portions of the black resin layer located in the gaps 4 between the plurality of color pixels 2.
As a light source used for exposure, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, or the like is used. The photosensitive wavelength range of the black photosensitive composition is 400 n
When the number is more than m, a black photosensitive resin is formed as a residue on the plurality of color pixels by light passing through the plurality of color pixels. Therefore, it is preferable to perform exposure through a visible light cut filter. Then, a crosslinking reaction is caused only in the gap portions 4 of the multi-color pixels 2 of the black resin layer 3 by using a catalytic reaction of an acid by a heat treatment at 90 ° C. to 150 ° C. for a time period of 15 seconds to 5 minutes. Next, using a developing solution, the black resin in the uncrosslinked portions on the multi-color pixels 2 is removed, and a black matrix 5 made of the black resin is formed between the multi-color pixels 2 as shown in FIG. A color filter is created. When the black matrix 5 is thicker than the multi-color pixels 2, a grinding process may be performed. Sodium hydroxide,
Inorganic alkali solutions such as potassium hydroxide, sodium carbonate and potassium carbonate, alkylamines such as triethylamine, alcoholamines such as triethanolamine, and quaternary ammonium salts such as tetramethylammonium hydroxide can be used.

With the conventional method of exposing from the back side of a transparent substrate, it was necessary to cure the inside of the black resin layer with a large amount of ultraviolet rays, but with the black photosensitive resin composition of the present invention, high sensitivity was obtained. Since a small amount of exposure generates an acid and a cross-linking curing reaction occurs, it is possible to form a black matrix with a small amount of exposure without depending on the absorption in the ultraviolet region of multiple color pixels and the optical density of the black resin layer. Becomes As a result, it is possible to obtain a black density sufficient to block light, and it is not necessary to add an ultraviolet absorber or the like to the multi-color pixels, so that the optical characteristics are not degraded, and the black resin on the multi-color pixels is not deteriorated. Can be removed. Further, in the case of the black photosensitive resin composition of the present invention, since the polymer compound having an alkyl group having 3 to 12 carbon atoms in the side chain is added, the flexibility of the black matrix itself is improved, and The adhesion to the substrate is increased.

[0021]

As shown in FIG. 2, on a transparent glass substrate (Corning Co., Ltd .: "7059") 1, red,
Colored patterns of green and blue pixels were formed. The pixels of each color include “color mosaic CRY7000”, “color mosaic CGY7000”, and “color mosaic CB”, respectively.
V7000 "manufactured by Fuji Hunt. The film thickness of these multi-color pixels was 1.5 μm. 100 g of each component shown in Table 1 and glass beads were put into a glass bottle, and dispersed for 2 hours using a paint shaker to prepare a dispersion of a black photosensitive resin composition.

[0022]

[Table 1]

This black photosensitive resin dispersion is applied on a red, green, and blue colored pattern formed of a plurality of color pixels by a spinner at 760 rpm for 5 seconds, dried, and dried to form a black resin as shown in FIG. Layer 3 was formed. The entire surface was exposed from the transparent substrate 1 side with a multi-color pixel 2 as a mask at an exposure amount of 60 mJ / cm ² by a 3 kW ultra-high pressure mercury lamp. afterwards,
Heating was performed at 90 ° C. for 1 minute using a hot plate. Using a 1.25% aqueous solution of sodium hydroxide, the spraying is performed while rotating the substrate, and the spraying is performed.
The development was performed for seconds, and the unexposed portions on the multi-color pixels of the black resin layer 3 were removed. Finally 230 in a clean oven
C. for 1 hour to obtain a color filter.

(Evaluation of Adhesion) The color filter prepared in the above example was allowed to stand at 120 ° C., 100% RH and 2 atm for 50 hours, and the black matrix was measured using a pre-shake cooker according to JIS K5400. The adhesiveness was evaluated by the test method for adhesion to a substrate. As a result, the number of strips in the black matrix is 0/10
It was 0. [Comparative Example] A color filter having a black photosensitive resin composition or a black matrix formed thereon was prepared in the same manner as in the above example except that poly (2-ethylhexyl acrylate) was not added. Was performed. As a result, the number of peelings in the black matrix was 100/100, and it was not possible to obtain adhesion.

[0025]

The black photosensitive resin composition of the present invention is not only a resin composition having a high light reflectance on the surface, but also a highly sensitive resist itself and a high γ value, so that it is practical and economical. A black matrix having a predetermined pattern can be sufficiently formed at an exposure amount which is level and does not cause fogging on a plurality of color pixels. In addition, since the back exposure method can be applied without adding an additive such as an ultraviolet absorber or a fluorescent whitening agent to each of the multi-color pixels serving as a mask, no projections are formed, and There is no accompanying deterioration in optical characteristics such as performance and contrast ratio. Furthermore, since the black photosensitive resin composition of the present invention is excellent in flexibility, it has high adhesion to a glass substrate, and the black resin does not easily peel off from the substrate.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an example of a color filter.

FIG. 2 is a cross-sectional view illustrating one process of a manufacturing example of a color filter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Multi-color pixel 3 Black resin layer 5 Black matrix

Claims (2)

[Claims] 1. A resinous material of 20 to 45% by weight, a crosslinking agent 5
-20% by weight, photoacid generator 2-15% by weight, black pigment 2
In a black photosensitive resin composition containing 0 to 60% by weight, a polymer compound having an alkyl group having 3 to 12 carbon atoms in a side chain is added in an amount of 5 to 80% by weight based on the resin material. A black photosensitive resin composition comprising: 2. The method according to claim 1, wherein said resin-based material is capable of forming a crosslinking point.
The black photosensitive resin composition according to claim 1, which is a polymer compound containing an H group and soluble in an aqueous alkali solution.