JPH0815519A - Color paste and its production - Google Patents

Abstract

PURPOSE:To form a color filter from a polyimide poor in solvent resistance by incorporating a water soluble org. amine more than a specified times mol. equivalent of a carboxyl group of polyamic acid, a pigment and water. CONSTITUTION:The water soluble org. amine binds in base form to the carboxyl group of the polyamic acid and becomes to a water soluble polyimide precursor. Further, when an amount of the water soluble org. amine binding in base form is too low, the polyimide precursor composition does not dissolve to water. In order to easily dissolve the precursor in the water. it is necessary to add >=0.5mol. equivalent water soluble org. amine per polyamic acid. Moreover, in this water based color paste, a pigment is dispersed in an aq. soln. of the polyimide precursor. Methyl amine, ethyl amine, n-propyl amine, 2 ethanol amine, 2-amino-2 methyl 1 propanol are a concrete example of the water soluble orb. amine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous color paste mainly used in the electronic industry. More specifically, it relates to an aqueous color paste that can be used for forming a color filter of a liquid crystal display device or an image pickup device.

[0002]

2. Description of the Related Art As a color paste capable of forming a color filter having excellent heat resistance and light resistance, a color paste in which a pigment is dispersed in an organic solvent solution of polyamic acid is known (for example, JP-A-60). -18420
No. 2, JP-A-60-184203, JP-A-6
1-180203).

However, although the flash point of a polar organic solvent which is usually used as a solvent for polyamic acid is higher than room temperature, the temperature becomes higher than the flash point in the heating and drying process for forming a coating film, and exhaust is insufficient. An explosion may occur in some cases. Furthermore, organic solvents cause health problems and adversely affect the environment.

The production of a color filter using a color paste in which a pigment is dispersed in an organic solvent solution of polyamic acid is disclosed, for example, in JP-A-60-247603 and JP-A-61-77804. As described above, the following steps are performed. First, a color paste (for example, green) is applied on a substrate and then dried to form a polyimide precursor colored film. A positive photoresist is applied on the polyimide precursor colored coating to form a photoresist coating. A mask is placed on the photoresist film, and ultraviolet rays are irradiated using an exposure device. After exposure, with an alkaline developer for positive photoresist,
The photoresist coating and the polyimide precursor colored coating are etched simultaneously. After etching, the photoresist film that is no longer needed is removed. After that, the polyimide precursor is converted into polyimide by heat treatment.
In this way, a pattern of one color of the polyimide colored film is formed on the substrate, and then a color paste of another color (for example, red) is applied thereon, and the same process is performed to
A pattern of colored polyimide colored coating is formed on the substrate. When this is repeated once again, a pattern of three colored polyimide coatings of red, blue and green is obtained.

In this step, a color paste containing an organic solvent is applied onto the polyimide colored coating film, so that the polyimide is required to have a high solvent resistance. However, a polyimide having excellent transparency in a short wavelength region generally has poor solvent resistance. When a color paste in which a pigment is dispersed in an organic solvent solution of polyamic acid is applied on these highly transparent polyimide films, problems such as roughening of the surface of the polyimide film and cracks occur, and a color filter consisting of multiple colors Is difficult to form.

[0006]

SUMMARY OF THE INVENTION The present invention was devised in view of the above-mentioned drawbacks of the prior art. The object of the present invention is to use an organic solvent that is dangerous to health and environment because of danger of ignition and the like. Another object of the present invention is to provide a water-based color paste that does not require a solvent and is capable of forming a color filter with a polyimide having poor solvent resistance.

[0007]

The object of the present invention is as follows.
This is achieved by the following configuration. (1) A color paste containing (a) a polyamic acid, (b) a water-soluble organic amine in an amount of 0.5 times a molar equivalent or more of a carboxyl group of the polyamic acid, (c) a pigment, and (d) water. (2) Color in which a polyamic acid, an aqueous solution of a polyimide precursor containing a water-soluble organic amine in an amount of 0.5 times or more a molar equivalent of a carboxyl group of the polyamic acid and water, and a pigment dispersion liquid in which a pigment is dispersed in water are mixed. Paste manufacturing method. (3) A method for producing a color paste, which comprises mixing a pigment with a polyamic acid, a polyimide precursor aqueous solution containing 0.5 times or more molar equivalents of a carboxyl group of the polyamic acid, a water-soluble organic amine and water.

The polyamic acid referred to here is represented by the following general formula (1).

[0009]

Embedded image Wherein R ₁ is a tetravalent organic group having 2 to 22 carbon atoms, R ₂ denotes a divalent organic group, n is an integer of 1 or more of 1 to 22 carbon atoms. The higher the molecular weight, the better the mechanical properties of the polyimide film. Therefore, it is desired that the polyamic acid, which is a polyimide precursor, also has a large molecular weight. On the other hand, when performing pattern processing by wet etching the polyimide precursor film, if the molecular weight of the polyamic acid is too large,
There is a problem that the time required for development becomes too long.
Therefore, the preferable range of n is 2 to 1000, more preferably 4 to 400, and further preferably 6 to 100. Since the molecular weight of the polyamic acid generally varies, the preferable range of n here is 50 mol% or more, preferably 70 mol% or more, and more preferably 90 mol% of the total polyamic acid within this range. Means that more than% is included.

In the color paste of the present invention, a water-soluble organic amine is salt-bonded to the carboxyl group of the above polyamic acid to form a water-soluble polyimide precursor. In addition,
When the amount of salt-bonded water-soluble organic amine is too small,
The polyimide precursor composition does not dissolve in water. In order to easily dissolve in water, it is necessary to add the water-soluble organic amine to the polyamic acid in an amount of 0.5 times the molar equivalent of the carboxyl group of the polyamic acid or more, preferably 0.6 times the molar equivalent or more. It is desirable to add 0.7 times or more molar equivalents, more preferably 0.8 times or more molar equivalents.

The water-soluble organic amine used in the present invention is
It is a compound obtained by substituting hydrogen atoms of ammonia with an organic group and is soluble in water, and specific examples thereof include methylamine, ethylamine, n-propylamine, 2-ethanolamine and 2-amino-. Primary amines such as 2-methyl-1-propanol, dimethylamine, secondary amines such as 2- (methylamino) ethanol, 2- (ethylamino) ethanol, 2-dimethylaminoethanol, 2-diethylaminoethanol, 1-
Examples thereof include tertiary amines such as dimethylamino-2-propanol, and quaternary amines such as tetramethylammonium hydroxide and tetraethylammonium hydroxide. The present invention is not limited to these,
One or more water-soluble organic amines are used.

The polyamic acid can be obtained by reacting a tetracarboxylic dianhydride and a diamine.

The tetracarboxylic dianhydride has the general formula (2)

Embedded image (R ₁ in the formula represents the above-mentioned tetravalent organic group having 2 to 22 carbon atoms). In the present invention, as the tetracarboxylic dianhydride, for example, an aliphatic or alicyclic type can be used, and specific examples thereof include 1,
2,3,4-cyclobutanetetracarboxylic dianhydride,
1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,3,5-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-bicyclohexenetetracarboxylic dianhydride , 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,3,3a, 4,5,9
b-Hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-C] furan-
1,3-dione and the like can be mentioned. Further, when an aromatic type is used, a polyimide precursor composition that can be converted into a polyimide having good heat resistance can be obtained, and specific examples thereof include 3,3 ′, 4,4′-benzophenone. Tetracarboxylic dianhydride, pyromellitic dianhydride, 3,
4,9,10-perylenetetracarboxylic dianhydride,
3,3 ′, 4,4′-diphenylsulfone tetracarboxylic acid dianhydride, 4,4′-oxydiphthalic anhydride,
3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,3 ", 4,4" -paraterphenyltetracarboxylic acid The dianhydride and 3,3 ", 4,4" -metaterphenyl tetracarboxylic acid dianhydride can be mentioned. Also,
When a fluorine-based compound is used, a polyimide precursor composition having good transparency in a short wavelength region and capable of being converted into a polyimide having a small dielectric constant can be obtained. -(Hexafluoroisopropylidene) diphthalic anhydride and the like can be mentioned. The present invention is not limited to these, and one or more tetracarboxylic dianhydrides may be used.

The diamine is represented by the general formula (3) H ₂ N—R ₂ —NH ₂ (3) (wherein R ₂ represents the divalent organic group having 1 to 22 carbon atoms). Be done. In the present invention, as the diamine, for example, an aliphatic or alicyclic diamine can be used, and specific examples thereof include ethylenediamine, 1,
3-diaminocyclohexane, 1,4-diaminocyclohexane, 4,4'-diamino-3,3'-dimethyldicyclohexylmethane, 4,4'-diamino-3,3 '
-Dimethyldicyclohexyl and the like. Also,
When an aromatic compound is used, a polyimide precursor composition that can be converted into a polyimide having good heat resistance can be obtained, and specific examples thereof include 4,4′-diaminodiphenyl ether and 3,4′- Diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 3,3'-
Diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfide, m-
Phenylenediamine, p-phenylenediamine, 2,4
-Diaminotoluene, 2,5-diaminotoluene, 2,
6-diaminotoluene, benzidine, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, o-
Trisine, 4,4 "-diaminoterphenyl, 1,5-
Diaminonaphthalene, 3,3'-dimethyl-4,4'-
Diaminodiphenylmethane, 4,4'-bis (4-aminophenoxy) biphenyl, 2,2-bis [4- (4-
Aminophenoxy) phenyl] propane, bis [4-
(4-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] sulfone,
Examples thereof include bis [4- (3-aminophenoxy) phenyl] sulfone. Further, when using a fluorine-based one, it is possible to obtain a polyimide precursor composition which has good transparency in a short wavelength region and can be converted into a polyimide having a small dielectric constant. 2-bis [4-
(4-aminophenoxy) phenyl] hexafluoropropane and the like.

The general formula (4)

Embedded image (R ₃ in the formula is a divalent organic group having 1 to 10 carbon atoms, R ₄ ,
R < ₅ >, R < ₆ >, and R < ₇ > are monovalent organic groups having 1 to 10 carbon atoms, which may be the same or different, and m means an integer of 1 to 10. By using the siloxane diamine represented by the formula (4), the adhesiveness with the inorganic substrate can be improved. The siloxane diamine is usually used in an amount of 1 to 20 mol% based on all diamines. If the amount of siloxane diamine is too small, the effect of improving the adhesiveness will not be exhibited, and if it is too large, the heat resistance will decrease. Specific examples of the siloxane diamine include bis-3- (aminopropyl) tetramethylsiloxane. The present invention is not limited to these, and one or more diamines may be used.

The polyamic acid is generally synthesized by mixing diamine and tetracarboxylic dianhydride in a polar organic solvent and reacting them. At this time, the degree of polymerization of the polyamic acid obtained can be adjusted by the mixing ratio of the diamine and the tetracarboxylic dianhydride. From the polyamic acid solution thus obtained, by reprecipitation, using a technique such as vacuum drying, by removing the solvent,
A polyamic acid can be obtained.

In addition, there are various methods for obtaining polyamic acid, such as by reacting tetracarboxylic acid dichloride and diamine in a polar organic solvent and then removing hydrochloric acid and the solvent to obtain polyamic acid. However, the present invention can be applied to polyamic acid regardless of the synthetic method.

The following method can be used for producing the water-soluble polyimide precursor. A water-soluble organic amine is added to a polar organic solvent solution of the polyamic acid, and the water-soluble organic amine is salt-bonded to the carboxyl group of the polyamic acid. Then, the organic solvent is removed to obtain a water-soluble polyimide precursor. When this is dissolved in water, a polyimide precursor aqueous solution is obtained.

There is also a method of obtaining an aqueous polyimide precursor solution by dissolving a polyamic acid in an aqueous solution of a water-soluble organic amine. In this case, the polyamic acid and the water-soluble organic amine may be simultaneously mixed with water to obtain a polyimide precursor aqueous solution, or the polyamic acid may be dispersed in water, and then the water-soluble organic amine may be added to the polyimide precursor. A body water solution may be obtained.

The aqueous color paste of the present invention comprises a pigment dispersed in the above-mentioned polyimide precursor aqueous solution. The pigment used in the present invention is not particularly limited, but those having excellent light resistance, heat resistance and chemical resistance are preferable. Specific examples of typical pigments are shown by color index (CI) numbers. Examples of yellow pigments include Pigment Yellow 20, 24, 83, 86, 93, 94, 109, 11
0, 117, 125, 137, 138, 139, 14
7, 148, 153, 154, 166, 173 and the like. Pigment Orange 1 is an example of an orange pigment.
3, 31, 36, 38, 40, 42, 43, 51, 5
5, 59, 61, 64, 65 and the like. Examples of red pigments are Pigment Red 9, 97, 122, 1
23, 144, 149, 166, 168, 177, 18
0, 192, 215, 216, 224 and the like. An example of a purple pigment is Pigment Violet 1.
9, 23, 29, 32, 33, 36, 37, 38 and the like. Pigment Blue 1 as an example of a blue pigment
5 (15: 3, 15: 4, 15: 6, etc.), 21, 2
2, 60, 64 and the like. Pigment green 7, 10, 36, 47 etc. are mentioned as an example of a green pigment. Examples of black pigments include Pigment Black 7. In the present invention, various pigments can be used without being limited thereto. The pigment may be subjected to surface treatment such as rosin treatment, acidic group treatment, and basic treatment, if necessary.

Color filters R (red), G (green) and B (blue) used in the liquid crystal display device.
Since it is necessary for the color pixels to be similar to the chromaticity characteristics of the CRT phosphor, the above pigments are used in a combination of several colors so as to match the light transmission characteristics of the backlight and the liquid crystal display element. For example, R (red) is toned with a red pigment and a yellow pigment or an orange pigment, G (green) is toned with a green pigment and a yellow pigment or an orange pigment, and B (blue) is toned with a combination of a blue pigment and a purple pigment. Further, as the black matrix of the color filter, a black pigment or, if necessary, a mixture of pigments of other colors can be used.

In the aqueous color paste of the present invention, the polyamic acid and the pigment are usually used in a weight ratio of 2: 8-9 :.
1, preferably 3: 7 to 8: 2, more preferably 4: 6.
The mixture is used in the range of 7: 3. If the amount of polyamic acid is too small, the adhesion of the colored coating to the substrate becomes poor, and if the amount of pigment is too small, the degree of coloring becomes a problem.

The concentration of the polyamic acid in the color paste is preferably 0.5 to 25% by weight,
It is more preferably 1 to 15% by weight.

For the production of the aqueous color paste of the present invention,
There are a method of mixing a dispersion liquid in which a pigment is previously dispersed in water and a polyimide precursor aqueous solution, and a method of dispersing a pigment in a polyimide precursor aqueous solution. Either way,
The pigment is dispersed in water or an aqueous solution, but the dispersing method is not particularly limited, and various methods such as a ball mill, a sand grinder, a three roll mill, and a high speed impact mill can be used.

The aqueous color paste of the present invention may contain an organic solvent in an amount of 50% by weight or less of water in order to improve coating properties and drying properties of the colored coating film. It is preferably 30% by weight or less, more preferably 10% by weight or less. If the amount of the organic solvent is too large, the advantages as an aqueous solution (such as non-explosiveness) are lost. The organic solvent that can be contained in the aqueous color paste according to the present invention is preferably water-soluble, and specific examples thereof include alcohols such as ethanol, butanol and ethylene glycol, methyl cellosolve, ethyl cellosolve and the like. Cellosolves, carbitols such as methyl carbitol and ethyl carbitol, N, N-dimethylacetamide,
Examples thereof include amides such as N, N-dimethylformamide, lactones such as γ-butyrolactone and β-propyllactone, and pyrrolidones such as 2-pyrrolidone and N-methyl-2-pyrrolidone. In the present invention, the organic solvent is not limited to these, and one or more organic solvents can be used.

For the same purpose or for the purpose of improving the dispersibility of the pigment, a surfactant can be added to the aqueous color paste of the present invention. The amount of the surfactant added is usually 0.001 to 10% by weight of the pigment, preferably 0.
It is from 0 to 1% by weight. If the amount added is too small, coating properties
There is no effect of improving the drying property of the colored film or the dispersibility of the pigment. If the amount is too large, on the contrary, the coatability becomes poor and the pigment aggregates. Specific examples of the surfactant, ammonium lauryl sulfate, anionic surfactants such as polyoxyethylene alkyl ether sulfate triethanolamine, stearylamine acetate, cationic surfactants such as lauryl trimethyl ammonium chloride, lauryl dimethylamine oxide, Amphoteric surfactants such as lauryl carboxymethyl hydroxyethyl imidazolium betaine, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether,
Examples include nonionic surfactants such as sorbitan monostearate. In the present invention, the surfactant is not limited to these, and one or more surfactants can be used. The addition of the surfactant can be carried out during the pigment dispersion process or at any time before or after the process. But,
Care must be taken because the dispersibility of the pigment may change depending on the time of addition.

Further, a colloidal substance of inorganic fine particles may be added to the aqueous color paste of the present invention in order to improve the hardness of the colored film. Specific examples of the colloidal substance of inorganic fine particles include silica sol, titania sol, zirconia sol, etc., but are not particularly limited thereto. When adding a colloidal substance of inorganic fine particles, the addition amount is preferably 1 to 50% by weight of the polyamic acid,
2 to 30% by weight is more preferable. If the added amount is too large, the colored coating becomes brittle, and if the added amount is too small, the effect of improving the hardness of the colored coating is not exhibited.

As a method for coating the aqueous color paste of the present invention on a substrate, a spin coater, a bar coater,
Various methods such as a blade coater, a roll coater, a die coater, a method of coating the substrate by a screen printing method, a method of immersing the substrate in an aqueous solution, and a method of spraying the aqueous solution on the substrate can be used. As the substrate, a transparent substrate such as soda glass, non-alkali glass, borosilicate glass, or quartz glass, or a semiconductor substrate such as silicon or gallium-arsenide is usually used, but is not particularly limited thereto. When the aqueous color paste is applied on the substrate, if the substrate surface is treated with an adhesion aid such as a silane coupling agent, an aluminum chelating agent, or a titanium chelating agent, the adhesion between the colored coating and the substrate is improved. be able to.

The water-based color paste of the present invention is used for a color filter of a liquid crystal display or an image pickup device, a light-shielding film of an optical element, a coating film of an optical fiber and the like.
For example, an optical fiber coated with a colored coating using an aqueous color paste can be used as an optical sensor under high temperature.

Next, an example of a method of using the color filter for liquid crystal display, which is a typical application of the water-based color paste of the present invention, will be described.

After coating the aqueous color paste on the transparent substrate by the above-mentioned method, the polyimide precursor colored coating is formed by air drying, heat drying, vacuum drying or the like. In the case of heat drying, it is preferable to use an oven, a hot plate or the like, and to perform the heating in the range of 50 to 180 ° C. for 1 minute to 3 hours. Next, a pattern is formed on the thus obtained polyimide precursor colored film by ordinary wet etching. First, a positive photoresist is applied on the polyimide precursor colored coating to form a photoresist coating. Subsequently, a mask is placed on the photoresist film, and ultraviolet rays are irradiated using an exposure device. After the exposure, the photoresist coating and the polyimide precursor colored coating are simultaneously etched with a positive photoresist alkaline developer. After etching, the photoresist film that is no longer needed is removed.

The polyimide precursor colored film is then converted into a polyimide colored film by heat treatment. The heat treatment is usually performed in air, in a nitrogen atmosphere, or in a vacuum at 150 to 450 ° C., preferably 18 ° C.
It is carried out continuously or stepwise at a temperature of 0 to 350 ° C. for 0.5 to 5 hours.

A color filter for a liquid crystal display can be manufactured by carrying out the above steps for three color pastes of R (red), G (green) and B (blue) and, if necessary, black color paste. .

[0034]

EXAMPLES The present invention will now be described in detail with reference to Examples, but the present invention is not limited thereto.

Example 1 300 equipped with a thermometer and a dry nitrogen inlet and a stirrer
In a 0 ml four-necked flask, 294.2 g (1 molar equivalent) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenylmethane 94.2.
g (0.475 molar equivalent), 3,3′-diaminodiphenyl sulfone 117.9 g (0.475 molar equivalent), bis-3- (aminopropyl) tetramethylsiloxane 1
2.4 g (0.05 molar equivalent) and 1556.1 g of γ-butyrolactone were added, and the temperature was 60 ° C. under a dry nitrogen inflow.
After stirring for 4 hours, a γ-butyrolactone solution of polyamic acid (polymer concentration 25% by weight) was obtained.

A solution of 3.4 g (0.038 mol equivalent) of 2-dimethylaminoethanol added to 500 g of γ-butyrolactone while stirring the solution while diluting the solution with a polymer concentration of 10% by weight to obtain a γ-butyrolactone solution of polyamic acid. 100 g (containing 0.019 molar equivalent of polyamic acid)
Was dropped to obtain a white precipitate. The precipitate was separated by filtration, washed with toluene, and vacuum dried to obtain a water-soluble polyimide precursor powder. 4 g of this water-soluble polyimide precursor powder and 46 g of water were mixed and stirred at 60 ° C. to obtain a homogeneous polyimide precursor aqueous solution.

Pigment Red 177 (Chromophtal red) (4 g) and water (46 g) were dispersed together with 100 g of glass beads using a homogenizer at 7,000 rpm for 30 minutes, and the glass beads were removed by filtration.

To 20 g of the pigment dispersion, 20 g of an aqueous polyimide precursor solution was added and mixed to obtain an aqueous color paste of the present invention. This color paste was spin-coated on a non-alkali glass substrate and heated and dried in air using an oven at 50 ° C. for 10 minutes, 90 ° C. for 10 minutes, and 110 ° C. for 20 minutes to give a film having a thickness of 1.6 μm. A polyimide precursor film was obtained. A positive photoresist (Tokyo Ohka Co., Ltd.
FPR-800) was applied and heated and dried at 80 ° C. for 20 minutes to obtain a resist film having a film thickness of 1 μm. An intensity of 50 mJ / c at a wavelength of 365 nm is obtained through a photomask made of chrome using an ultraviolet exposure device PLA-501F manufactured by Canon Inc.
It was irradiated with m ² of ultraviolet rays. After the exposure, the photoresist and the colored film of the polyimide precursor were developed at the same time by immersing in a developing solution composed of a 2.38 wt% aqueous solution of tetramethylammonium hydroxide. After etching, the unnecessary photoresist layer was peeled off with methyl cellosolve acetate. Further, the polyimide precursor colored film thus obtained was heat-treated at 300 ° C. for 30 minutes in a nitrogen atmosphere to obtain a polyimide colored film having a thickness of 1.2 μm.

Example 2 400 g of a solution prepared by diluting the γ-butyrolactone solution of the polyamic acid obtained in Example 1 (polymer concentration 25% by weight) to 5% by weight with γ-butyrolactone was added to toluene 400.
Toluene was added dropwise to 0 g with stirring to obtain a white precipitate. The precipitate was separated by filtration and vacuum dried to obtain a polyamic acid powder.

5 g of polyamic acid powder (0.0096
(Molar equivalent), 50 g of water, 1.37 g of dimethylaminoethanol (0.0154 molar equivalents) are mixed,
The mixture was stirred with to obtain a homogeneous polyimide precursor aqueous solution. Pigment Green 7 (Phthalocyanine Green) 4g and ethylene glycol 5g were added to this aqueous solution, and a homogenizer was used together with 100g of glass beads to obtain 7,000.
After dispersion treatment for 30 minutes at rpm, the glass beads were removed by filtration.

Using the thus obtained aqueous color paste, a patterned polyimide colored coating film was obtained in the same manner as in Example 1.

Example 3 2.35 g (0.03 g) of 2-aminoethanol was added to 50 g of water.
84 molar equivalents) were mixed. To this, 5 g (0.0096 molar equivalent) of the polyamic acid powder obtained in Example 2 was added.
Was added and stirred at 50 ° C. to obtain a homogeneous polyimide precursor aqueous solution.

Pigment Blue 15 (phthalocyanine blue) (3 g) and water (47 g) were dispersed together with 100 g of glass beads using a homogenizer at 7,000 rpm for 30 minutes, and the glass beads were removed by filtration. 20 g of the polyimide precursor aqueous solution was added to and mixed with 15 g of the pigment dispersion liquid to obtain an aqueous color paste. Using this aqueous color paste, the same operation as in Example 1 was carried out to obtain a patterned polyimide colored coating film.

Example 4 300 equipped with a thermometer and dry nitrogen inlet and a stirrer
In a 0 ml 4-necked flask, add 1 part of pyromellitic dianhydride.
09.1 g (0.5 molar equivalent), 3,3 ', 4,4'-
Benzophenone tetracarboxylic dianhydride 161.1 g
(0.5 molar equivalent), 4,4'-diaminodiphenyl ether 190.2 g (0.95 molar equivalent), bis-3-
(Aminopropyl) tetramethylsiloxane 12.4 g
(0.05 molar equivalent) and 1891.2 g of N-methyl-2-pyrrolidone were added, and under a dry nitrogen inflow, 50 ° C.
After stirring for 5 hours, an N-methyl-2-pyrrolidone solution of polyamic acid (polymer concentration 20% by weight) was obtained.

This solution was added to a polymer concentration of 10% by weight with N--
To 100 g of a liquid diluted with methyl-2-pyrrolidone (containing 0.021 molar equivalent of polyamic acid), 9.84 g (0.084 molar equivalent) of 2-diethylaminoethanol was added. This liquid was added dropwise to 1000 g of toluene while stirring toluene to obtain a white precipitate. The precipitate was separated by filtration and vacuum dried to obtain a water-soluble polyimide precursor powder. Then, 4 g of the water-soluble polyimide precursor powder and 36 g of water were mixed and stirred at 70 ° C. to obtain a homogeneous polyimide precursor aqueous solution.

Pigment Red 177 (Chromoftal Red) 3.5 g, Pigment Yellow 83 (Benzidine Yellow) 0.5 g, and water 46 g are added to glass beads 100.
Using a homogenizer with g, 3 at 7,000 rpm
After the dispersion treatment for 0 minutes, the glass beads were removed by filtration.

To 20 g of the pigment dispersion, 18 g of a polyimide precursor aqueous solution and 2 g of ethylene glycol were added and mixed to obtain an aqueous color paste. This color paste is spin-coated on a non-alkali glass substrate, and at 80 ° C. for 10 minutes,
It was heated and dried in air at 120 ° C. for 20 minutes in an oven to obtain a polyimide precursor film having a film thickness of 1.5 μm. The same operation as in Example 1 was carried out using a photoresist to obtain a patterned polyimide precursor colored film. Then, using a hot plate, in air at 270 ℃
Was heat-treated for 10 minutes to obtain a polyimide colored film having a thickness of 1.1 μm.

Example 5 N-methyl-2-of the polyamic acid obtained in Example 4
5% by weight of pyrrolidone solution (polymer concentration 20% by weight)
400g diluted with N-methyl-2-pyrrolidone
Was dropped into 4000 g of toluene with stirring to obtain a white precipitate. The precipitate is separated by filtration,
Vacuum drying was performed to obtain a polyamic acid powder.

5 g of polyamic acid powder (0.0106
(Molar equivalent), 50 g of water, 3.73 g of diethylaminoethanol (0.0318 molar equivalent) are mixed, and 60 ° C.
The mixture was stirred with to obtain a homogeneous polyimide precursor aqueous solution. Pigment Green 7 (Phthalocyanine Green) 3 g, Pigment Yellow 83 (Benzidine Yellow) 0.6 g, and ethylene glycol 5 g were added to this aqueous solution, and a homogenizer was used together with 150 g of glass beads.
After the dispersion treatment at 00 rpm for 30 minutes, the glass beads were removed by filtration. Using this aqueous color paste, a patterned polyimide colored coating film was obtained in the same manner as in Example 4.

Example 6 In place of 3.73 g of diethylaminoethanol in Example 5, 2.83 g (0.031 g of dimethylaminoethanol) was used.
An aqueous color paste was obtained in the same manner except that (8 molar equivalent) was used. Using this, a patterned polyimide colored coating film was obtained by the same procedure as in Example 5.

Example 7 300 equipped with thermometer and dry nitrogen inlet and stirrer
In a 0 ml 4-neck flask, add 1,3,3a, 4,5,9
b-Hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-C] furan-
1,3-dione 300.3 g (1 molar equivalent), 4,4 '
180.2 g (0.9 molar equivalents) of diaminodiphenyl ether, 24.9 g (0.1 molar equivalent) bis-3- (aminopropyl) tetramethylsiloxane, and N-
1516.2 g of methyl-2-pyrrolidone was added, and the mixture was stirred at 60 ° C. for 4 hours under an inflow of dry nitrogen to obtain an N-methyl-2-pyrrolidone solution of polyamic acid (polymer concentration 25% by weight).

This solution was added to a polymer concentration of 10% by weight with N--
2-amino-2-into 100 g of liquid diluted with methyl-2-pyrrolidone (containing 0.020 molar equivalent of polyamic acid)
5.35 g (0.060 molar equivalent) of methyl-1-propanol was added. This liquid was added dropwise to 1000 g of toluene while stirring toluene to obtain a white precipitate. The precipitate was separated by filtration and vacuum dried to obtain a water-soluble polyimide precursor powder. 4 g of the powder of the water-soluble polyimide precursor and 40 g of water were mixed and stirred at 60 ° C. to obtain a homogeneous polyimide precursor aqueous solution.

20 g of this aqueous solution was mixed with 20 g of the pigment dispersion obtained by the same formulation as in Example 4 and 4 g of ethylene glycol to obtain an aqueous color paste. Using this, a patterned polyimide colored coating film was obtained by the same operation as in Example 4. The aqueous color paste prepared in Example 5 was spin-coated on this, and the same procedure as in Example 4 was carried out to obtain a two-color patterned polyimide colored coating film.

Comparative Example 1 The polyamic acid N-methyl-2-obtained in Example 7 was used.
The pyrrolidone solution (polymer concentration 25% by weight) was diluted with N-methyl-2-pyrrolidone to a polymer concentration 10% by weight. To this solution, 20 g of Pigment Green 7 (phthalocyanine green) 1.5 g, Pigment Yellow 83
(Benzidine yellow) (0.2 g) and N-methyl-2-pyrrolidone (15 g) were added, and the dispersion was treated at 7,000 rpm for 30 minutes using a homogenizer together with 60 g of glass beads, and then the glass beads were removed by filtration.

Using the aqueous color paste prepared in Example 7, the patterned polyimide colored coating film formed in the same manner as in Example 4 was spin-coated with an N-methyl-2-pyrrolidone-based color paste. Then, when it was dried by heating, the patterned polyimide colored coating film was partially dissolved and cracks were generated.

[0056]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, it is possible to use a normal wet coating without using an organic solvent which is dangerous to fire and is harmful to health and environment.
There is an advantage that a polyimide-based pigment-dispersed color filter having good heat resistance can be formed. Further, according to the present invention, a remarkable effect that a multicolor patterned color filter can be formed even if a polyimide having poor solvent resistance is used.

Claims (7)

[Claims] 1. A color paste containing (a) a polyamic acid, (b) a water-soluble organic amine in an amount 0.5 or more molar equivalents of a carboxyl group of the polyamic acid, (c) a pigment and (d) water. 2. The color paste according to claim 1, wherein the water-soluble organic amine is a secondary amine or a tertiary amine. 3. The color paste according to claim 1, which is a color paste for a color filter. 4. A polyimide precursor aqueous solution containing a polyamic acid, a water-soluble organic amine at a molar ratio of 0.5 times or more the carboxyl group of the polyamic acid and water, and a pigment dispersion liquid in which a pigment is dispersed in water. Method for producing color paste. 5. A method for producing a color paste, which comprises mixing a pigment with an aqueous solution of a polyimide precursor containing polyamic acid, a water-soluble organic amine in an amount of 0.5 times a molar equivalent or more of a carboxyl group of the polyamic acid, and water. 6. A method for producing the polyimide precursor aqueous solution comprises:
The method for producing a color paste according to claim 4 or 5, wherein a polyimide precursor obtained by adding a water-soluble organic amine to polyamic acid in an amount of 0.5 times a molar equivalent or more of a carboxyl group of the polyamic acid is dissolved in water. 7. A method for producing the polyimide precursor aqueous solution comprises:
The method for producing a color paste according to claim 4 or 5, wherein the polyamic acid is dissolved in an aqueous solution containing a water-soluble organic amine in an amount of 0.5 times a molar equivalent or more of a carboxyl group of the polyamic acid.