JP3120547B2 - Color paste for color filters - 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 such as a color liquid crystal television and a color liquid crystal display for a computer, and more particularly to a color filter coloring paste comprising an acrylic photosensitive composition containing a coloring component. .

[0002]

2. Description of the Related Art Conventionally, various methods for producing a color filter using an acrylic photosensitive composition have been proposed. These are mainly composed of a mixture of an acrylic acid polymer and a compound having an ethylenically unsaturated group, and the acrylic acid polymer, which is the main component, does not participate in the crosslinking reaction by light. For this reason, the difference between the solubility of the exposed part and the unexposed part in the developing solution during development is small, and as a result, the developability deteriorates and the pattern edge becomes unclear.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art. It is an object of the present invention to provide a pattern having good developability and having a sharp edge portion. is there.

[0004]

An object of the present invention is to provide an acrylic copolymer having a carboxyl group and an ethylenically unsaturated group in a side chain as a binder component, a coloring component, a polyfunctional thiol compound and This is achieved by a photosensitive composition comprising a photoinitiator.

The acrylic copolymer having a carboxyl group and an ethylenically unsaturated group in the side chain includes a polymer obtained by copolymerizing an unsaturated carboxylic acid and an ethylenically unsaturated compound with an ethylenically unsaturated moiety. Is reacted with a carboxylic acid group to form a side chain. The unsaturated carboxylic acid as a component constituting the polymer main chain is
Acrylic acid, methacrylic acid, itaconic acid, crotonic acid,
Maleic acid, fumaric acid, vinyl acetic acid, or 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 n-acrylate. Butyl, n-butyl methacrylate, sec-butyl acrylate, sec-butyl methacrylate, iso-butyl acrylate, iso-butyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, n-pentyl acrylate, Examples include, but are not limited to, n-pentyl methacrylate, styrene, p-methylstyrene, o-methylstyrene, m-methylstyrene, and the like. 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 a vinyl group, an allyl group, an acryl group and a methacryl group. The following method can be used to impart such a side chain to the acrylic copolymer. When the acrylic copolymer has a carboxyl group, a hydroxyl group, or the like, it is general to add an ethylenically unsaturated compound having a glycidyl group or acrylic acid chloride thereto. In addition, a compound having an ethylenically unsaturated group can be added using isocyanate. Glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, α-ethyl glycidyl acrylate, crotonyl glycidyl ether, crotonyl glycidyl ether, crotonyl glycidyl ether, glycidyl isocrotonic acid as the ethylenically unsaturated compound having a glycidyl group and acrylic acid chloride referred to here Ether, acrylic acid chloride, methacrylic acid chloride, allyl chloride, methallyl chloride and the like can be mentioned. The addition amount of these ethylenically unsaturated compounds is 0.05 to the carboxyl group of the acrylic copolymer.
It is preferably from 0.8 to 0.8 equivalent, more preferably from 0.1 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. It is preferable that the binder contains at least 5% by weight or more, more preferably 20% by weight or more of an acrylic copolymer having a carboxyl group and an ethylenically unsaturated group in the side chain, and the content is less than 5% by weight. In this case, there is no effect of enlarging the allowable development width, and as in the case of the conventional blending method, the developability is poor and a pattern with a sharp edge cannot be formed.

As coloring components, dyes and the like can be used alone or in combination in addition to conventional organic and inorganic pigments.
In the case of pigments, the color filter is intended for optical applications, and it is necessary to sufficiently finely disperse the pigment. To this end, it is important to select pigments with a large visible light absorption coefficient and a primary particle diameter sufficiently small for the wavelength of visible light, and to select a dispersant or surfactant suitable for each pigment. Become. In addition, it is important to select a device used for dispersion. These can be used because many findings have already been published.

The polyfunctional thiol compound has two or more -SH groups in the molecule. 1,2-benzenedithio-
1,3-benzenedithiol, 1,2-ethanedithiol,
1,3-propanedithiol, 1,6-hexamethylenedithio-
And 1,4-butanediol-dithiopropionate, di (mercaptoethyl) ether, and trimethylolpropane trimercaptopropionate, but are not limited thereto. -SH group is anti-Markownik radically or ionically to carbon-carbon unsaturated bond
It is known to add off.

In the present invention, since the acrylic copolymer as the binding component has an ethylenically unsaturated group in the side chain, a crosslink is formed between the copolymerized polymers by reaction with the added polyfunctional thiol compound. Then, the composition becomes three-dimensional.

When the reaction proceeds radically,
A radically polymerizable ethylenically unsaturated compound may be used in combination. Such polyfunctional monomers include bisphenol A diglycidyl ether acrylate, polyacrylate carbamate, modified bisphenol A epoxy acrylate, adipic acid 1,6-hexanediol acrylate, phthalic anhydride propylene oxide acrylate, and diethylene glycol trimellitate. Oligomers such as acrylic acid ester, rosin-modified epoxy diacrylate, and alkyd-modified acrylate, and tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, bisphenol A diglycidyl ether diacrylate, trimethylolpropane triacrylate, and pentaerythritol Examples include triacrylate. These can be used alone or as a mixture, and the following monofunctional monomers can also be used in combination. They include, for example, ethyl acrylate, ethyl methacrylate, 2-ethylhexyl methacrylate, hydroxyethyl methacrylate, 2-ethylhexyl acrylate, n-butyl methacrylate, glycidyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl methacrylate, stearyl acrylate, isobornyl methacrylate, isobornyl methacrylate Bornyl acrylate, a mixture of two or more thereof, or a mixture with another compound.

Known photopolymerization initiators 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. Also,
A sensitizing dye may be added to extend the photosensitive wavelength range. Dyes having such an effect include xanthene, acridine, oxazine, cyanine and the like. Other additives include stabilizers such as hydroquinone, hydroquinone monomethyl ether, mono-t-butylhydroquinone, catechol, picric acid, and malonic 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.

The crosslinking reaction can be initiated ionically, and a photoacid generator that generates an acid upon exposure is effective. For this, a diallyl iodonium compound or a triarylsulfonium compound is used. It is a component used for photopolymerization of an epoxy compound. “Irgacure” 261 ((η5
-2,4-Cyclopentadien-1-yl) [(1,2,3,4,5,6-η)-(1-met
hylethyl) benzene] -iron (1 +)-hexafluorophosphate (1
-), Ciba-Geigy Co., Ltd.) has a wide photosensitive wavelength range and high activity can be expected.

Since the unsaturated bond component is a composition system in which a large amount of the unsaturated bond component is used, a reaction by light is caused and a thermal reaction is also possible. In order to make full use of the two effects of light and heat,
It is also effective to add a thermal radical generator such as a peroxide or an azonitrile compound.

In order to obtain the colored paste of the present invention, a predetermined amount of an acrylic copolymer, a thiol compound, optionally a polyfunctional monomer having an ethylenically unsaturated group, a photoinitiator and other components are used. Dissolve and mix in a suitable solvent. Dyes for pixel coloring are selected for the three primary colors of red, green and blue, and these are sufficiently kneaded with a dispersing device such as a three-roll, homogenizer, or sand grinder. In this way, red, green,
Three blue colored pastes were prepared. The paste is applied to a glass substrate by setting a suitable condition by a spinner or a roll coater, dried and prebaked, exposed to light through a pixel mask, and developed with an aqueous alkali solution. The resulting patterned pixels are post-baked. This operation is sequentially performed for three colors to produce a color filter.

[0015]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples.

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, 30 g of methyl methacrylate and 40 g of styrene, and 30 g of methacrylic acid mixed with 2 g of N, N-azobisisobutyronitrile and added dropwise Add dropwise over 30 minutes with a funnel. 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 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 3 g of triethylbenzylammonium chloride were added and reacted for 3 hours. The product thus obtained was designated as polymer B. 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. Further, a paste having the following composition was prepared.

Polymer B 50% by weight Trimethylolpropane trimercaptopropionate 20% by weight Irgacure907 (CIBA-Geigy) 5% by weight Ethylene glycol monoethyl ether 200% by weight Chromophtal red A2B and Seika First are used as color pigments in this paste. Yellow 2720 (7/3) 20wt
%, Green is green 2YN / Seika First Yellow 2720 (8
/ 2) is 18wt%, blue is cyanine blue E / violet RVS
(7/3), add 18wt% each, and use a homomixer for 30mi
n. Stir to disperse the pigment. The pigment paste thus obtained was filtered under pressure with a 2 μm filter, and then applied to a glass plate with a spinner. After pre-baking at 80 ° C. for 10 minutes, pattern exposure was performed with a high-pressure mercury lamp, and development was performed with a 1% aqueous solution of sodium carbonate. Next, post-baking was performed at 200 ° C. for 30 minutes, and these steps were repeated three times to form a mosaic pattern of three colors on the glass plate. As a result, with respect to the developability, the unexposed part dissolves in the developing solution in 5 sec., The exposed part obtains a pattern which can be immersed in the developing solution for 1 to 5 min. Met.

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 40 g of methyl methacrylate, 30 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.

The polymer thus obtained was used in Example 1
The paste was applied in the same manner as described above, and the coating and patterning were evaluated. The unexposed portion was dissolved in the developing solution in 5 seconds.
A good pattern was obtained even when the exposed portion was immersed in the developing solution for 1 to 5 minutes. The edge of the pattern was sharp.

Example 3 In the composition of Example 1, 1,4-butanediol dithiopropionate was used as a thiol compound, and "Irga" was used as a photoinitiator.
Three colored pastes were prepared in the same manner except that "Cure" 261 was used.

Except for applying a roll coater to a glass substrate, the same exposure, development and baking treatment as in Example 1 was carried out to form a pixel to obtain a color filter.

[0022]

According to the present invention, there is provided a composition comprising an acrylic copolymer having an ethylenically unsaturated group and a carboxyl group in a side chain, a polyfunctional thiol compound, a photoinitiator, and a dye in a color paste for a color filter. Since the product was used, a high-performance color filter could be efficiently manufactured.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-201652 (JP, A) JP-A-48-30505 (JP, A) JP-A-3-289655 (JP, A) JP-A 63-2016 40141 (JP, A) JP-A-62-212436 (JP, A) JP-A-2-153353 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03F 7/038 G02B 5 / 20 101 G03F 7/004 G03F 7/028

Claims (5)

(57) [Claims] An acrylic copolymer having a carboxyl group and an ethylenically unsaturated group in a side chain as a binder component, and a photosensitive composition containing a coloring component, a polyfunctional thiol compound and a photoinitiator. A coloring paste for a color filter, comprising: 2. The colored paste for a color filter according to claim 1, wherein the acrylic copolymer having a carboxyl group and an ethylenically unsaturated group contains at least styrene and methyl methacrylate as copolymer components. 3. The color filter coloring paste 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. 4. The colored paste for a color filter according to claim 1, wherein the binder contains at least 5% by weight or more of an acrylic copolymer having a carboxyl group and an ethylenically unsaturated group in a side chain. 5. The color filter according to claim 1, wherein an acrylic copolymer obtained by adding an ethylenically unsaturated compound having a glycidyl group to an acrylic copolymer having a carboxyl group is used as a binder component. For coloring paste.