JP2819512B2 - Coloring composition for color filter, method for producing color filter, and color filter - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a color filter used for a liquid crystal color display or an image sensor.

2. Description of the Related Art Conventionally, a color filter used for a liquid crystal color display or an image sensor includes a red (hereinafter referred to as R), a green (hereinafter referred to as G) and a blue (hereinafter referred to as B) on a transparent substrate such as glass. Mosaic or striped pixel pattern of the three primary colors (printed or lithographic method) of the three primary colors of R, G, and B, because there are difficulties in the separation and clarity of each color. , R, G and B by adding a black matrix to the three colors has been proposed.

Examples of the method for forming the black matrix include: (1) a method of depositing a metal such as chromium, (2) a dyeing method using a black dye, and (3) a printing method using a printing ink containing carbon black or a black compound dye. (4) A lithographic method using a photosensitive black resin composition has been proposed.

(Problems to be Solved by the Invention) The above-mentioned method (1) has drawbacks in that the cost is high, the steps are complicated and the productivity is not improved, and the equipment and the like are large and expensive. In the method (2), there is no good dye for dyeing black, and it is necessary to mix two or three color dyes to dye black, resulting in color unevenness and inability to dye black with sufficient density. There is a problem. In the printing method using the black ink of the method (3), fine processing is difficult, and it is difficult to form a black matrix with sufficient accuracy. Further, in the lithographic method using a photosensitive resin containing a black pigment in the method (4), although sufficient accuracy can be ensured, when carbon black is used, the photocuring becomes insufficient or when carbon black is used. Poor light blocking due to poor dispersion,
There was a problem of conductivity specific to carbon black. Further, when a black dye is used, there is a problem in heat resistance and weather resistance when a high temperature treatment is performed, and it has not been put to practical use.

Accordingly, an object of the present invention is to solve the problems associated with the conventional black matrix formation and to provide a color filter having a black matrix with high accuracy and excellent light-shielding properties.

(Means for Solving the Problems) As a result of various studies of black organic pigments having absorption in the visible light region for use as a black matrix, the present inventors have found that a black pigment having a specific structure is effective in solving the above problems. The present invention has been completed by finding that such means are provided.

That is, the present invention relates to a photosensitive black pigment-containing coloring composition for forming a black matrix on a color filter substrate, wherein the black pigment is an azo pigment having in its molecule a residue represented by the following general formula: A coloring composition for a color filter, a method for producing a color filter using the coloring composition, and a color filter obtained as a result.

(Where Ar is a residue of an aromatic or heterocyclic compound, X is a hydrogen atom or a halogen atom,
Is an integer of 1 or more. (Operation) Conventionally, carbon black has been used as a black pigment of printing ink used for general printing and the like.

Carbon black generally has poor dispersibility in a resin varnish and tends to aggregate in the resin varnish. In particular, when dispersed in a photosensitive resin solution or the like, the dispersibility is poor. When a black matrix is formed with this, gaps are formed between the pigment particles, and the light-shielding property may be reduced.

Further, carbon black has the property of inhibiting the polymerization reaction of the photosensitive resin, and therefore has the disadvantage of inhibiting the photocuring reaction of the resin.

Further, carbon black absorbs light uniformly from the ultraviolet to the infrared region, and is sometimes difficult to use in a photocurable lithographic method. When a black dye such as Solvent Black 3 is used, a black matrix is used. Although the light-shielding property of this is sufficient, when it is used by dissolving it in a heat-resistant resin such as polyimide varnish, the baking conditions for closing the polyimide may be discolored due to the use of a high temperature.

In contrast, the azo black pigment having an azomethine group-containing residue in the molecule used in the present invention has absorption in the visible light region, but impairs its photocurability even when incorporated into a photosensitive resin. Not only does it not only resist heat treatment and weather resistance, it also withstands heat treatment during the manufacture of color filters, but also has sufficient durability and weather resistance when using color filters.

Further, the pigment type black pigment has good dispersibility in a photosensitive varnish and excellent storage stability.

In addition, when the ITO electrode of a color filter used for a liquid crystal color television or the like is formed on a substrate by vapor deposition, a high-temperature heat treatment is required, but if a black pigment excellent in heat resistance used in the present invention is used, Such a problem of heat resistance can be easily solved.

(Preferred Embodiment) Next, the present invention will be described in more detail with reference to preferred embodiments.

The coloring composition for a color filter of the present invention is obtained by dispersing an azo pigment having a residue having an azomethine group in a molecule in a photosensitive resin varnish into a photosensitive coloring composition to obtain a photosensitive coloring composition. Thus, a desired black matrix can be formed by patterning on a transparent glass substrate.

The black pigment used in the present invention will be described in more detail.

An azo pigment having a residue having an azomethine group in the molecule is an azo pigment having a residue containing an azomethine chromophore represented by the following general formula (I) in a diazo component or a coupling component, or both. It is a system pigment.

Ar, X and m in the above formula are as defined above.

The diazo component having an azomethine group is diazotized in accordance with a conventional method, and is subjected to a coupling reaction with a conventionally known coupling component or a coupling component having an azomethine group, thereby obtaining an azo pigment having an azomethine group used in the present invention. I can do it.

Alternatively, the azo pigment having an azomethine group used in the present invention can be obtained by diazotizing a conventionally known diazo component and performing a coupling reaction with a coupling component having an azomethine group.

In the residue (I) having an azomethine group, Ar is a residue of an aromatic or heterocyclic compound, for example, a benzene ring, a naphthalene ring, an anthracene ring, a pyridine ring and the like.

Examples of the diazo component having an azomethine group include 3- (4'-aminophenylimino) -1-oxo-4,
5,6,7-tetrachloroisoindoline, 3- (3'-aminophenylimino) -1-oxo-4,
5,6,7-tetrachloroisoindoline, 3- (2'-aminophenylimino) -1-oxo-4,
5,6,7-tetrachloroisoindoline, 3- (4 "-amino-diphenyl-4'-imino) -1
-Oxo-4,5,6,7-tetrachloroisoindoline, etc. and their phenylene or diphenylene groups are substituted with one or more substituents such as halogen, methyl, methoxy, ethoxy, nitro, etc. And the like.

Conventionally known coupling components used for the coupling reaction with the diazo component having the azomethine group include, for example, CI azoic coupling components 1, 2, 1
0, 22, 17, 27, 18, 31, 8, 21, 29, 20, 34, 41,
6, 11, 24, 19, 12, 23, 14, 30, 46, 4, 7, 40,
3, 32, 36, 25, 13, 15, 16, 5, 35, 13, 19, acetoacetate anilide, acetoacetate-2-methylanilide, acetoacetate-4-methylanilide, acetoacetate-2,4 -Dimethylanilide, acetoacetic acid-2-methoxyanilide, acetoacetic acid-2-chloroanilide, acetoacetic acid-2-methoxy-5-methyl-4-chloroanilide, acetoacetic acid-2,5-dimethoxy-4 Acetoacetic allylamides such as -chloroanilide and acetoacetic acid-4-chloro-2-nitroanilide; 3-methyl-1-phenyl-5-pyrazolone, 1-phenyl-5-pyrazolone-3-carboxylic acid Ethyl ester, hydroxynaphthoic acid, phenol and the like can be mentioned.

Examples of the coupling component having the azomethine group include 2-hydroxy-3-naphthoic acid, 2-pidroxy-anthracene-3-carboxylic acid, 3-hydroxybenzofuran-2-carboxylic acid, 2-hydroxy Coupling carboxylic acids such as carbazole-3-carboxylic acid, 2-hydroxy-α-benzocarbazole-3-carboxylic acid, 1-phenyl-5-pyrazolone-3-carboxylic acid, and acetoacetic acid with the azomethine group And those obtained by subjecting the amino compound to a condensation reaction.

Conventionally known diazo components used for the coupling reaction with the above-mentioned coupling component having an azomethine group include, for example, CI azoic diazo components 44, 2, 3, 6,
7, 37, 9, 16, 49, 17, 18, 19, 26, 33, 46, 11, 3
2, 34, 12, 8, 10, 5, 13, 1, 29, 31, 42, 14, 2
4, 43, 41, 40, 20, 15, 38, 51, 21, 23, 4, 27, 3
9, 48, 22, 47, 35, 45, 36, aniline, toluidine,
Anisidine, naphthylamine and the like can be mentioned.

The diazotization of the above components, the coupling reaction, the purification of the produced pigment, the pigmentation in the case of a pigment, and the like can be performed in a suitable medium such as an aqueous or organic solvent according to a conventional method.

Particularly preferred azo pigments having an azomethine group include, for example, JP-A-58-174446, Japanese Patent Application No. 59-4775, Japanese Patent No. 1063816, Japanese Patent No. 1052019, Japanese Patent No. 1141514. And azo pigments disclosed in Japanese Patent Application No. 1141515, Japanese Patent Application No. 60-168540, and Japanese Patent Application No. 60-277929.

An azo pigment having an azomethine group using 2-hydroxy-α-benzocarbazole-3-carboxylic acid allylamide and a derivative thereof as a particularly preferred coupling component shows a dark green to black color tone under visible light,
In particular, black shows a clear black with high blackness.

The azo pigment having an azomethine group is excellent in heat resistance, light resistance, water resistance, and chemical resistance, and has high coloring power. In addition, pigments of the pigment type exhibit extremely excellent solvent resistance.

As the varnish for dispersing the black pigment to form a photosensitive coloring composition, all varnishes used for ultraviolet curable ink, electron beam curable ink and the like can be used.

Examples of the photosensitive resin varnish of the present invention include a cyclized rubber-based resin used as a resist for a general semiconductor device, a phenol-based resin, a polymethyl methacrylate-based resin, a polymethyl isopropenyl ketone-based resin, a polyamide-based resin, A varnish such as a polyimide resin is used.

In addition, as a general photocurable resin varnish, a reactive diluent for unsaturated polyester resin, polyester acrylate resin, polyepoxy acrylate resin, polyurethane acrylate resin, polyether acrylate resin, polyol acrylate resin, etc. A varnish to which a monomer is added can also be mentioned.

By adding a photopolymerization initiator such as benzoin ether and benzophenone to the black pigment and the varnish, and kneading the mixture by a conventionally known method, the coating agent type photosensitive coloring composition of the present invention can be obtained. .

The addition weight ratio of the black pigment to the binder is
The range is preferably 5 parts to 400 parts with respect to 100 parts of the binder.

When a black matrix is formed using the above photosensitive resin coating agent, the coating agent is uniformly applied on a transparent substrate by a coating method such as spin coating or roll coating, and after predrying, a photomask is adhered. Exposure is performed using an ultra-high pressure mercury lamp. Next, development and washing are performed, and post-baking is performed as necessary, whereby a black matrix can be formed.

The black matrix formed as described above is
Similarly, a color display using a cathode ray tube, a color display using a light emitting diode, etc. is also used as a means for avoiding color bleeding or overlapping of color displays, and a color display which produces a clear and sharp image. Can be provided.

The color filter and the method for producing the same according to the present invention are characterized in that the black pigment-containing coloring composition is used for forming a black matrix as described above,
In addition, the color composition for forming the color filters R, G and B pixels and the forming method may be conventionally known ones. Preferred examples of the pigment used include, for example, CI Pigment Red 122, 123, 149, 177, 179, 190,
194, 207, 209, CI Pigment Yellow 24, 108, 109, 110, 166, CI Pigment Green 7, 36, 37, CI Pigment Blue 15, 60, 66 and the like.

Further, the present invention is not limited to the combination of the three primary colors of the pixels R, G and B of the color filter, and other combinations such as the combination of the three primary colors of indigo, red and yellow are of course possible.

(Effects) According to the present invention, by using a black pigment having a specific structure for forming a black matrix of a color filter, the heat resistance and weather resistance can be more easily and inexpensively compared with the conventional method. An excellent color filter is provided.

(Examples) Next, the present invention will be described more specifically with reference to examples.
In the description, parts and% are based on weight unless otherwise specified.

Production Example 1 (black pigment) 3- (4'-aminophenylimino) -1-oxo-
4,5,6,7-tetrachloroisoindoline diazotization,
2-hydroxy-N- (4'-methoxyphenyl) -11
A coupling reaction was performed with -H-benzo [a] -carbazole-3-carboxamide to obtain an azo pigment having an azomethine group. The azo pigment was black and had a thermal decomposition point of 373 ° C. (black pigment R-1).

Production Example 2 (black pigment) 3- (3'-aminophenylimide) -1-oxo-
4,5,6,7-tetrachloroisoindoline diazotization,
A coupling reaction with 1,4-bis- [2'-hydroxy-11'H-benzo [a] -carbazole-3'-carbonylamino] benzene was performed to obtain an azo pigment having an azomethine group. The azo pigment presents a slightly reddish black color,
It had a thermal decomposition point of 342 ° C. (black pigment R-2).
Was.

Example 1 The black pigments R-1, R, G and B of Production Example 1 were
It was dispersed in a photosensitive resin varnish mainly composed of a polyurethane acrylate resin using three rolls to prepare a UV-curable ink. The compounding was performed according to the following formulation.

Using a roll coater, the black ink was applied as a first color to a thickness of 5 μm before drying on a glass substrate surface-treated with a silane coupling agent. Then at 60 ° C 5
Pre-drying was performed for minutes. Thereafter, a photomask having a lattice pattern was brought into close contact, and exposure was performed at a light intensity of 400 mJ / cm using an ultrahigh pressure mercury lamp of 250 W. Next, the unexposed portions were washed away with a developer mainly composed of isopropyl alcohol / toluene / ethyl acetate, rinsed with isopropyl alcohol, and dried with dry air to obtain a grid-like black matrix having a cotton width of 50 μm.

A blue ink as the second color was uniformly applied by a roll coater on the glass substrate having a lattice black matrix obtained as described above. The same drying as in the case of the black ink was repeated, and blue pixels were formed at predetermined positions in a lattice-like black matrix on a glass substrate.

Using the green ink and the red ink as the third color and the fourth color, respectively, the same operation as the blue ink is repeated to form G and R patterns to obtain R, G and B color filters having a black matrix. Was.

The arrangement of the three colors of R, G and B is alternately and repeatedly filled in the black matrix lattice, and is exposed using a photomask of each of R, G and B so as not to be adjacent to each other. G and B patterns were obtained.

The R, G, and B color filters having the mosaic pattern obtained above form a clear color reproducibility image without overlapping of each color because the R, G, and B colors are separated by a black matrix. Can be done.

Example 2 From the photosensitive polyimide resin varnish containing the black pigments R-1, R, G and B of Example 1 and the photosensitizer containing the photosensitizer, four colors were prepared using the following formula and three rolls. A photosensitive coating agent for a filter was prepared.

The glass plate treated with the silane coupling agent was set on a spinner and spin-coated with the above black coating agent. First at 1,500 rpm for 30 seconds, then at 4,000 rpm for 5 seconds
Spin coating was performed under the condition of seconds.

Next, prebaking was performed at 65 ° C. for 30 seconds, and a photomask having a lattice pattern was adhered thereto, and exposure was performed using an ultrahigh pressure mercury lamp at a light amount of 900 mJ / cm ² .

Next, development and washing were performed with a dedicated developer and a dedicated rinse, and post-baking was performed at 200 ° C. for 30 minutes and at 300 ° C. for 60 minutes to obtain a glass substrate having a grid-like black matrix pattern with a line width of 20 μm.

Using a blue coating agent as the second color, a green coating agent as the third color, and a red coating agent as the fourth color, the same operation as the black coating agent was repeated three times to obtain a color filter having a mosaic pattern. . The arrangement of each color of R, G and B was the same pattern as in Example 1.

The color filter obtained above has a narrow black matrix width of 20 μm, has no separation of R, G and each color, and is excellent in separability and luminance, and can form a very clear image.

Comparative Example 1 A black photosensitive polyurethane acrylate resin ink was obtained using the black ink formulation of Example 2 except that carbon black was used in place of the black pigment R-1 used in Example 1.

Comparative Example 2 A black photosensitive polyimide resin coating agent was obtained using the black ink formulation of Example 2 except that Solvent Black 3 was used in place of the black pigment R-1 used in Example 2. .

Example 3 The black coating agent obtained in Example 1 and Comparative Example 2 was
Roll coating was performed to a thickness of about 5 μm before drying on the glass substrate that had been treated with the silane coupling agent. At 60 ° C
It was dried for 10 minutes and cured with an ultra-high pressure mercury lamp under the conditions of 400 mJ / cm ² to form a uniform coating film on the entire surface of the glass substrate. The glass substrate coated with the above two inks was subjected to a goban test to check the adhesion of the coating film and a pencil hardness test to check the hardness of the coating film. The results are shown in Table 1. Table 1 Goban eye test Pencil hardness Black coating of Example 1 100% 5H Black coating of Comparative Example 1 20% 4B As is clear from the results in Table 1, the carbon black used in Comparative Example 1 was UV cured. It is a factor that hinders against.

Example 4 The black coating agent obtained in Example 2 and Comparative Example 2 was roll-coated with a coating thickness of 10 μm on a glass substrate that had been treated with a silane coupling agent. Then 65
Pre-bake for 30 minutes at 200 ° C, 30 minutes at 200 ° C, and 300 ° C
Post-baking was performed for 60 minutes to form a uniform coating film on the entire surface of the glass substrate.

Using a spectrophotometer (Model 330 manufactured by Hitachi, Ltd.), the transmittance of the black coating film before and after post-baking in the visible light region in the range of 400 nm to 700 nm, that is, the light-shielding property of the black matrix obtained in the present invention was measured. . The results are shown in Table 2.

As is evident from Table 2, Solvent Black 3 used in Comparative Example 2 shows sufficient light-shielding properties before post-baking, but transmits most of the light after post-baking, and has almost no light-shielding properties. On the other hand, the black coating agent of Example 2 showed almost no change in transmittance before and after post-baking, and exhibited excellent light-shielding properties.

Example 5 As a black pigment R-1 and a red pigment used in Example 1,
Using CI Pigment Red 122, CI Pigment Yellow 166 as a yellow pigment, and CI Pigment Blue 15 as an indigo pigment, 10 parts of a color pigment, 50 parts of a photosensitive polyimide resin varnish, and N- 40 parts of methyl-2-pyrrolidone are sufficiently uniformly dispersed using a three-roll mill and coated with a photosensitive polyimide resin of yellow (abbreviated as Y), red (abbreviated as M), indigo (abbreviated as C) and black An agent was prepared.

By the same operation as in Example 2, the first color is black, a lattice-like pattern is formed, the second color is indigo, the third color is red,
YMC with the fourth color yellow and black matrix
A color filter was formed.

When the YMC color filter obtained above was used as a color separation filter for printing ink, an effect excellent in color reproducibility was exhibited. Similar results were obtained for the black pigment (R-2) of Production Example 2.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-30202 (JP, A) JP-A-63-220203 (JP, A) JP-A-63-253302 (JP, A) JP-A 62-202302 32149 (JP, A)

Claims (5)

(57) [Claims] 1. A photosensitive black pigment-containing coloring composition for forming a black matrix on a color filter substrate, wherein the black pigment is an azo pigment having a residue represented by the following general formula in a molecule. A coloring composition for a photosensitive color filter, comprising: (Where Ar is a residue of an aromatic or heterocyclic compound, X is a hydrogen atom or a halogen atom,
Is an integer of 1 or more. ) 2. A method for producing a color filter, comprising a step of forming a black matrix on a substrate with a coloring composition containing a photosensitive black pigment, wherein the black pigment has a residue represented by the following general formula in a molecule. A method for producing a color filter, which is an azo pigment. (Where Ar is a residue of an aromatic or heterocyclic compound, X is a hydrogen atom or a halogen atom,
Is an integer of 1 or more. ) 3. A color filter in which a black matrix is formed on a substrate using a coloring composition containing a photosensitive black pigment, wherein the black pigment is an azo pigment having a residue represented by the following general formula in a molecule. A color filter characterized by the following. (Where Ar is a residue of an aromatic or heterocyclic compound, X is a hydrogen atom or a halogen atom,
Is an integer of 1 or more. ) 4. The color filter according to claim 5, wherein the color filter includes a red pixel, a green pixel, and a blue pixel, and the pixels are divided by a black matrix. 5. The color filter according to claim 5, wherein the color filter comprises a red pixel, a yellow pixel, and a blue pixel, and the pixels are divided by a black matrix.