JP3248696B2 - Color filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter suitable for a color liquid crystal display device such as a color liquid crystal television and a color liquid crystal display for a computer. A color filter having a color filter layer.

[0002]

2. Description of the Related Art Color pixels of a color filter are produced by a dyeing method, a printing method, an electrodeposition method, a photosensitive paste method, or the like. These are all performed by a combination of a patterning technique and a coloring technique. Since pixel formation is performed repeatedly in three colors of red, green and blue, it is difficult to make the finished surface uniform and smooth. It is necessary to provide fine functions such as formation of a transparent electrode on the pixel surface. For smoothing the surface of the pixel material itself, an overcoat having a leveling ability, being transparent and having appropriate hardness is required. is necessary. For this purpose, polyimide resins or acrylic resins have been used, but there have been problems such as the necessity of high-temperature treatment, generation of wrinkles and cracks, insufficient surface hardness, and removal of unnecessary portions of overcoat.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art, and has been developed in consideration of the above-mentioned conventional technology, which has good transparency, sufficient hardness, and excellent ability to smooth a pixel forming surface. The purpose of the present invention is to use the hydrophilic composition for the overcoat layer.

[0004]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
A pattern of red, green, and blue colored pixel layers is formed on a transparent substrate, and at least styrene and methyl
Kurire - including the door as a copolymerization component, and an acrylic copolymer having a carboxyl group and an ethylenic unsaturated group in the side chain as a binding component, to which a polyfunctional ethylenically unsaturated compound and a photoinitiator and extender pigments This is achieved by a color filter having an overcoat layer cured by irradiating a photosensitive composition containing the same with ultraviolet rays.

[0005] As the acrylic copolymer having a carboxyl group and an ethylenically unsaturated group in the side chain, an ethylenically unsaturated group is added to a polymer obtained by copolymerizing an unsaturated carboxylic acid and an ethylenically unsaturated compound. It is added as a pendant. Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, vinyl acetic acid, and acid anhydride.

On the other hand, examples of the ethylenically unsaturated compound include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, isopropyl acrylate, n-propyl methacrylate, isopropyl methacrylate, and acrylic acid. n-butyl, n-butyl methacrylate, sec-butyl acrylate, sec-butyl methacrylate, iso-butyl acrylate, iso-butyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, n-butyl acrylate Examples include pentyl, n-pentyl methacrylate, styrene, p-methylstyrene, o-methylstyrene, m-methylstyrene and the like, but are not particularly limited thereto. As a copolymer component of these acrylic copolymers, at least styrene and methyl methacrylate are included among the above-mentioned ethylenically unsaturated compounds, so that polymerization with good reproducibility can be performed. Can also be higher.

The side chain having an ethylenically unsaturated group includes vinyl groups, allyl groups, acryl groups and methacryl groups. The method of adding such a side chain to an acrylic copolymer is, when the acrylic copolymer has a carboxyl group or a hydroxyl group, etc., an ethylenically unsaturated compound having a glycidyl group on these, acrylic acid or methacrylic acid. A general method is to make chloride by an addition reaction. 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 crotonic acid, glycidyl ether isocrotonic acid. , Acrylic acid chloride, methacrylic acid chloride and the like. The addition amount of these ethylenically unsaturated compounds is preferably 0.05 to 0.8 equivalent to the carboxyl group of the acrylic copolymer.
1 to 0.6 equivalent. If the addition amount of the ethylenically unsaturated compound is less than 0.05 equivalent, the allowable development width is narrow and the pattern edge is poorly cut. On the other hand, if the added amount is larger than 0.8 equivalent, the solubility of the developer in the unexposed portion becomes poor, and the hardness of the coating film becomes low, so that a practical color filter cannot be obtained. Further, an acrylic copolymer having a carboxyl group and an ethylenically unsaturated group in a side chain is at least 5% by weight or more, more preferably 20% by weight in the composition.
If the content is less than 5% by weight, there is no effect of increasing the allowable development width, and the same as the conventional blending method, the developability is poor and a pattern with sharp edges cannot be formed.

As polyfunctional monomers, bisphenol A diglycidyl ether (meth) acrylate, poly (meth) acrylate carbamate, modified bisphenol A
Epoxy (meth) acrylate, adipic acid 1,6-hexanediol (meth) acrylate, phthalic anhydride propylene oxide (meth) acrylate, trimellitate diethylene glycol (meth) acrylate, rosin-modified epoxy di (meth) Oligomer such as acrylate, alkyd-modified (meth) acrylate, tripropylene glycol di (meth) acrylate, 1.6-hexanediol di (meth) acrylate, bisphenol A diglycidyl ether di (meth)
Examples include acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, and triacryl formal. These can be used alone or as a mixture. The following monofunctional monomers can also be used in combination. They are, for example, ethyl (meth) acrylate, 2-
Ethylhexyl methacrylate, hydroxyethyl methacrylate, 2-ethylhexyl acrylate, n-butyl methacrylate, glycidyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl methacrylate, stearyl acrylate, isobornyl methacrylate, isobornyl acrylate, and two or more of these. Or a mixture with other compounds. By selecting and combining these polyfunctional and monofunctional monomers and oligos, it is possible to control the reactivity and the properties of the reactants.
To increase the hardness of the coating layer, a methacrylate compound is preferable to an acrylate compound, and a low molecular weight component or a component having three or more functional groups is preferable.

As the photopolymerization initiator, known ones can be used, for example, α-aminoacetophenone, anthraquinone, benzoin ether, benzyl, benzophenone,
4,4'-bisdimethylaminobenzophenone, 4,4'-bistrichloromethylbenzophenone, dibutylphenylphosphine, α, α-diethoxyacetophenone, 2-ethylanthraquinone, benzoin bisphenyl, chlorobenzophenone, benzoin, benzoin methyl ether Benzoin isobleether, anthraquinone oxanthon, methylorthobenzoylbenzoic acid, paradimethylaminoacetophenone, and the like, but are not limited thereto. Also, para-dimethylaminobenzoic acid ester and the like can be used as a sensitizing aid. Other additives include polymerization inhibitors such as hydroquinone, hydroquinone monomethyl ether, mono-t-butylhydroquinone, catechol and picric acid, lubricants such as paraffin wax, and extenders such as silica and calcium carbonate. An organic aluminum compound, an organic titanate compound, an organic zinc compound, an organic calcium compound, or the like may be added.

An acrylic copolymer having a carboxyl group and an ethylenically unsaturated group in a side chain is used as a binding component in a colored pattern formed on a transparent substrate, and a polyfunctional ethylenically unsaturated compound and a photoinitiator are used. The solution of the compounded composition is applied by a rotary method or a roller method, dried, and then irradiated with ultraviolet rays through a mask that shields an unnecessary portion of the overcoat to remove an unexposed portion. A transparent film can be formed on the pixel forming portion.
In order to improve the hardness of the coating, means such as irradiating ultraviolet rays, heating the whole, or irradiating ultraviolet rays with heating can be applied. To promote curing by heating,
It is effective to add a thermal decomposition type radical generator, and it is possible to select and add necessary additives to the photosensitive composition.

[0011]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Example 1 10 ml of isopropyl alcohol was placed in a 1000 ml four-necked flask.
0 g, and kept at 80 ° C in an oil bath with nitrogen sealing and stirring, while mixing 30 g of methyl methacrylate and 40 g of styrene, and 30 g of methacrylic acid with 2 g of N, N-azobisisobutyronitrile and adding it dropwise. Drop over 30 minutes with funnel. Thereafter, after continuing the 4Hr reaction, 1 g of hydroquinone monomethyl ether was added, and the temperature was returned to room temperature to complete the polymerization. The product thus obtained was designated as polymer A. Next, 100 g of isopropyl alcohol was added to the polymer A, and while maintaining the temperature at 75 ° C., 40 g of glycidyl methacrylate and triethylbenzylammonium chloride were added.
3 g was added and reacted for 3 hours. The product thus obtained was designated as polymer B. Here, the reaction rate of glycidyl methacrylate was obtained from the change in polymer acid value before and after the reaction.
70%. Therefore, the added amount was 0.73 equivalent.
The composition of the photosensitive composition is as follows.

Polymer B 50 wt% trimethylolpropane triacrylate 20 wt% α-aminoacetophenone 5 wt% ethylene glycol monoethyl ether 200 wt% The step of applying and dispersing a pigment dispersion paste in red is
The above photosensitive composition solution was applied on a transparent substrate on which colored pixels were formed by performing the three colors of green and blue with a spinner, and prebaked at 80 ° C. for 10 minutes. Then, the film was exposed through a mask having an opening at its periphery and developed with a 1% aqueous solution of sodium carbonate. The transparent overcoat is formed only in the colored pixel portion. 200 ° C, 3
Bake for 0min. And proceed hardening. The hardness of the obtained overcoat film was 3H in terms of Empitz hardness, and the surface smoothness was good.

Example 2 10 ml of isopropyl alcohol was placed in a 1000 ml four-necked flask.
0 g, and kept at 80 ° C. in an oil bath with nitrogen sealing and stirring, while mixing 10 g of methyl methacrylate, 60 g of styrene, and 30 g of methacrylic acid with 2 g of N, N-azobisisobutyronitrile and dropping it. Add dropwise over 30 minutes with a funnel. Then, after continuing the 4Hr reaction, 1 g of hydroquinone monomethyl ether was added, and the temperature was returned to normal temperature to complete the polymerization. The product thus obtained was designated as polymer C.
Next, after 100 g of isopropyl alcohol was added to the polymer C, 40 g of glycidyl methacrylate and 3 g of triethylbenzylammonium chloride were added while maintaining the temperature at 75 ° C., and a reaction was carried out for 3 hours. The product thus obtained was designated as polymer D. Here, the reaction rate of glycidyl methacrylate was 70% as determined from the change in polymer acid value before and after the reaction. Therefore, the added amount was 0.73 equivalent. Using the polymer thus obtained, a composition was prepared in the same manner as in Example 1 except that 5% by weight of a pyrolytic radical generator, benzoyl peroxide, was added. After spin coating, drying was performed at 60 ° C., followed by patterning exposure and development. Thereafter, the mixture was heated to 100 ° C. and irradiated with ultraviolet rays from a high-pressure mercury lamp to cure the entire surface. A transparent overcoat having a glossy smooth surface with an Empitz hardness of 4H was obtained.

Example 3 A polymer was polymerized in the same manner as in Example 1 except that maleic acid was used in place of methacrylic acid.
A photosensitive composition was prepared in the same manner. 5 wt% of triacrylformal was added as a polyfunctional unsaturated compound, and 3 wt% of "Irgacure" 651 (Ciba-Geigy) was used as a photoinitiator. The overhead hardness of the overcoat layer produced in the same manner as in Example 1 was 4H.

[0016]

According to the present invention, at least styrene and methylmethac
An acrylic copolymer containing a relay as a copolymerization component and having a carboxyl group and an ethylenically unsaturated group in a side chain as a binding component, a polyfunctional ethylenically unsaturated compound, a photoinitiator, and an extender pigment. A transparent, high hardness, and smooth surface can be obtained by using a composition obtained by irradiating the photosensitive composition containing UV-cured and cured as an overcoat of a color filter.

Claims (4)

(57) [Claims] 1. A red, green and blue colored pixel layer in the form of a pattern is formed on a transparent substrate, and at least styrene and
And methyl methacrylate as a copolymer component, and an acrylic copolymer having a carboxyl group and an ethylenically unsaturated group in a side chain as a binding component, and a polyfunctional ethylenically unsaturated compound A color filter comprising an overcoat layer obtained by curing a photosensitive composition containing a photoinitiator and an extender pigment by irradiating ultraviolet rays. 2. The color filter according to claim 1, wherein the amount of the ethylenically unsaturated group in the acrylic copolymer is 0.05 to 0.8 equivalent relative to the carboxyl group. 3. An acrylic copolymer having a carboxyl group and an ethylenically unsaturated group in a side chain at least in the composition.
The color filter according to claim 1, wherein the content of the color filter is 5% by weight or more. 4. An acrylic copolymer obtained by adding an ethylenically unsaturated compound having a glycidyl group to an acrylic copolymer having a carboxyl group as a binding component. -Filters.