JPH1060274A - Polyimide-based resin composition, color filter and liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition, excellent in aggregation preventing properties of a dispersed pigment and stability and useful as a color filter and a liquid crystal display element by including a polyimide-based resin containing at least two specific polyimide precursors, a solvent and the pigment as principal components therein. SOLUTION: This polyimide-based resin composition comprises a polyimide- based resin containing at least two polyimide precursors of the formula [R1 is a 6-30C tri- or tetravalent organic group; R2 is a 6-30C bivalent organic group; (n) is 1-2] in which at least one selected from the organic groups R1 and R2 of the formula is different, a solvent (preferably a polar solvent such as dimethyl sulfoxide) and a pigment (preferably an organic pigment) as principal components. The composition is capable of providing a color filter having a flat coating film surface without any coating unevenness at a high contrast ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyimide resin composition which is excellent in preventing aggregation and stability of a dispersed pigment, and a color filter and a liquid crystal display device comprising the same.

[0002]

2. Description of the Related Art As a method for forming a colored layer of a color filter used in a liquid crystal display device, a dyeing method, a pigment dispersion method, an electrodeposition method, a printing method, and the like are known. Among these, in the coloring resin material used in the pigment dispersion method, organic and inorganic pigments are used as a coloring agent, and as a resin, it is known to use a polyimide-based, PVA-based, acrylic-based, epoxy-based, or the like. ing. Among them, polyimide resins are known to be useful as a color filter material because they have high heat resistance and high reliability, and are less discolored in a transparent electrode film forming step and an alignment film heating step (for example, see Japanese Unexamined Patent Publication No.
0-184202, JP-A-60-184203). Further, as a method of forming a color filter using a polyimide resin in which a pigment is dispersed as a coloring layer, a photolithography method disclosed in JP-A-60-247603 or JP-A-61-77804 is known.

[0003]

In such a conventional method, a polyimide resin composition in which a pigment is dispersed in a polyamic acid polymer (polyimide precursor) is used.
Since polyamic acid has high polarity, it is soluble only in polar solvents such as N-methyl-2-pyrrolidone, dimethylacetamide, β-propiolactone, and γ-butyrolactone, which are high in polarity and high in boiling point, or in a limited solvent such as a mixed solvent thereof. There are drawbacks.

[0004] It is originally difficult to form an electric or steric repelling group for dispersion stabilization on the surface of a pigment, and even if a polyimide resin composition is prepared by forcibly dispersing the pigment, the rheology of the polyimide resin composition is high. The characteristic is to exhibit extremely high pseudoplasticity due to aggregation of the pigments.

[0005] In the method of applying a polyimide resin composition in which a pigment is dispersed on a transparent substrate, methods such as dip coating, a roll coater, a wooler, a spin coater, and a curtain flow are used. The pigment-dispersed polyimide resin composition having a high content tends to cause uneven coating, and cannot form a high-quality color filter. For example, using such a pseudo-plastic highly pigment-dispersed polyimide-based resin composition, if this is applied by a method of spin coating with a spin coater, the thickness of the portion of the rotation center portion where the normal stress is small, or thicker, There is a tendency that traces of coating liquid dispensing and radial coating unevenness occur, that is, it is difficult to obtain a coating film free from coating defects.

Therefore, the color filter formed by such a method causes coating unevenness, lowering of contrast ratio, lowering of flatness of the coating film surface due to aggregation of the pigment particles, and the like. A fatal disadvantage that an excellent image cannot be obtained.

[0007] In view of the background of the prior art, the present invention provides
It is excellent in preventing aggregation due to aggregation of pigments, that is, it is intended to provide a stable polyimide resin composition without pseudoplasticity, and furthermore, a color filter comprising such a polyimide resin composition, further using it It is an object of the present invention to provide a liquid crystal display device capable of obtaining an excellent image.

[0008]

The present invention employs the following means to achieve the above object. That is, the polyimide-based resin composition of the present invention contains a polyimide-based resin, a solvent, and a pigment as main components, and the polyimide-based resin is a precursor represented by the general formula (1); At least one of the organic group R ₁ and the organic group R ₂ contains at least two different precursors.

[0009]

Embedded image Further, the color filter of the present invention is characterized in that such a polyimide-based resin composition is used for a light-transmitting colored pattern formed on a transparent substrate,
Further, the liquid crystal display element of the present invention is characterized by being constituted using such a color filter.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is free from unevenness of coating, lowering of contrast ratio and lowering of flatness of a coating film surface due to aggregation of pigments. In order to provide a stable polyimide-based resin composition and thus provide a color filter from which an excellent image can be obtained, after intensive studies, one was a specific polyimide precursor, which was also used in combination of two or more. In the case where a compound is blended, one of the problems is solved when the specific dispersant is blended, and the problem is solved at once.

The polyimide resin used in the present invention includes, for example, polyamideimide as long as it is a polyimide resin, and is not particularly limited, but a polyimide precursor having a structural unit represented by the general formula (1) Is characterized in that two or more of those defined below are used in combination.

[0012]

Embedded image That is, as the two or more kinds of polyimide precursors in the present invention, two or more kinds of polyimide precursors in which at least one selected from the organic group R ₁ and the organic group R _{2 of the} general formula (1) is different are mainly used. However, it may be a combination of a precursor having a structural unit of the general formula (1) having a repeating number of 10 or less and / or a polyimide precursor having a different method of sealing molecular terminals.

The polyimide precursor has a viscosity at the time of dispersing the pigment, a cohesiveness of the pigments, a coating property, an alkali etching property in a photolithography method, a heat resistance at the time of forming a color filter, a solvent resistance, They differ in mechanical strength, transparency, adhesion to a transparent substrate, contrast ratio, and the like. That is, it is generally difficult to balance each property with a single polyimide precursor, and for example, when selecting a polyimide precursor that emphasizes that there is no aggregation of pigments aimed at in the present invention, This may cause a situation where the alkali etching property in the photolithography method is reduced and the photolithography method cannot be put to practical use.

Thus, in the present invention, in order to obtain a pigment-dispersed polyimide precursor composition which does not exhibit pseudoplasticity due to aggregation of pigments and has no adverse effect on practical properties, two or more kinds of polyimide precursors having different properties are combined. Is used. More specifically, a combination of two or more polyimide precursors that emphasizes the absence of aggregation among the pigments and another type of polyimide precursor that compensates for the disadvantages of the polyimide precursor in practical characteristics is used.

In order to balance the properties of the polyimide precursor mixture, it is preferable that the individual polyimide precursor is mixed in an amount of preferably at least 10% by weight, more preferably at least 20% by weight with respect to all the polyimide precursors. However, the present invention is not limited to these.

In the above general formula (1), R ₁ is preferably a trivalent or tetravalent group containing a cyclic hydrocarbon, an aromatic ring or an aromatic heterocycle from the viewpoint of heat resistance. preferable.

Examples of R ₁ include phenyl, biphenyl, ta-phenyl, naphthalene, perylene, diphenylether, diphenylsulfone, diphenylpropane, benzophenone, diphenyltrifluoropropane and cyclobutyl. Group, cyclopentyl group, and the like, but are not limited thereto.

R ₂ is a divalent organic group having at least 2 or more carbon atoms. From the viewpoint of heat resistance, R ₂ is a group containing a cyclic hydrocarbon, an aromatic ring or an aromatic heterocyclic ring. preferable. Examples of R ₂ include a phenyl group, a biphenyl group, a terphenyl group, a naphthalene group, a perylene group, a diphenyl ether group, a diphenylsulfone group, a diphenylpropane group, a benzophenone group, a diphenyltrifluoropropane group, a diphenylmethane group, and dicyclohexyl. Examples include, but are not limited to, methane groups.

The polymer having the structural unit (1) as a main component is
R ₁ and R ₂ may each be composed of one of them, or may be a copolymer composed of two or more of each. Furthermore, in order to improve the adhesion to the substrate, as a diamine component as long as the heat resistance is not reduced,
It is preferable to copolymerize bis (3-aminopropyl) tetramethyldisiloxane having a siloxane structure.

Specific examples of the polymer having the structural unit (1) as a main component include pyromellitic dianhydride, 3,3 ′,
4,4′-benzophenonetetracarboxylic dianhydride,
3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-diphenyltrifluropropanetetracarboxylic dianhydride, 3,3 ', 4,4
'-Diphenylsulfonetetracarboxylic dianhydride,
At least one acid dianhydride selected from the group consisting of 2,3,5, -tricarboxycyclopentyl acetic acid dianhydride and the like, paraphenylenediamine, 3,3'-diaminodiphenyl ether, 4,4 '-Diaminodiphenyle-
Ter, 3,4 'diaminodiphenyl ether, 3,3'
A polyimide precursor synthesized from one or more diamines selected from the group of -diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodicyclohexylmethane, 4,4'-diaminodiphenylmethane, etc. But not limited thereto.

These polyimide precursors can be prepared by a known method,
That is, the acid dianhydride and the diamine are selectively combined,
It is synthesized by reacting in a solvent. After reacting the acid dianhydride and the diamine, it is normal to seal the molecular end with a dicarboxylic anhydride and stop the polymerization of the polyamic acid, but in the present invention, by a different method of sealing the molecular end,
Two or more kinds of polyimide precursors whose properties are controlled can be used as a mixture. For example, maleic anhydride, phthalic anhydride, nadic anhydride, succinic anhydride, and the like can be used as dicarboxylic anhydrides for blocking molecular terminals. Among these, the molecular end blocking with nadic anhydride is preferable from the viewpoint of preventing aggregation of the pigments in the pigment-dispersed polyimide precursor composition. Furthermore, a polyimide precursor which is prepared by reacting an acid dianhydride with a diamine in a solvent and then lowering the reaction temperature and which is not blocked with a molecular end by a dicarboxylic anhydride can also be preferably used.

As a solvent for synthesizing the polyimide precursor, a polar solvent is desirable from the viewpoint of solubility. Examples of such polar solvents include dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, amide-based polar solvents such as hexamethylphosphoramide, β-propiolactone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ Lactone solvents such as -caprolactone and ε-caprolactone can be used. These solvents can be used alone or in combination of two or more.

Since polar solvents for synthesizing a polyimide precursor all have too high a boiling point, it is preferable to use a solvent having a low boiling point as a secondary solvent from the viewpoint of improving coating properties and drying properties.

Examples of such co-solvents include alcohols such as methanol, ethanol and propanol, ethylene glycol such as methyl cellosolve, ethyl cellosolve, methyl carbitol, ethyl carbitol and propylene glycol monoethyl ether, propylene glycol derivatives, and propylene glycol monoethyl. Aliphatic esters such as ether acetate, ethyl acetoacetate, methyl-3-methoxypropionate, 3-methyl-3-methoxybutyl acetate, and 3-methoxybutyl acetate can be used. Among them, the boiling point is 100 ° C. like methanol, ethanol and propanol.
The following solvents are more preferably used because they have the effect of improving the coating properties and drying properties in a small amount.

These co-solvents can be used alone or in combination of two or more.
It is preferable to mix 1 to 30% by weight, more preferably 5 to 20% by weight in the total solvent, but it is not limited thereto.

The pigment used in the present invention includes an organic pigment and an inorganic pigment. From the viewpoint of preventing the aggregation of the pigment in the polyimide resin composition of the present invention, an organic pigment is particularly preferably used. To adjust the R (red), G (green), and B (blue) filters to desired colors, yellow, orange, and violet pigments are mixed as auxiliary pigments with red, green, and blue pigments as main pigments. Is also good. Examples of organic pigments include, as red pigments, Pigment Red-88, 122, 144, 146, 149, 168, 1
77, 202, 209, 216, as a yellow pigment, Pigment Yellow-17, 24, 83, 93, 94, 10
8, 109, 110, 138, 147, as a green pigment,
Pigment Green-7, 36, and as a blue pigment, Pigment Blue-15: 2, 15: 3, 15: 4, 15:
6. Pigment Violet-19, 2 as purple pigment
3, 32, 37, pigment orange as an orange pigment
13, 31, 36, 38, 40, 42, 43, 51, 5
5, 59, 61, 64, 65 and the like can be used, but are not limited thereto. These pigments can be subjected to a surface treatment such as a rosin treatment, an acid group treatment and a basic treatment as required.

The amount of the pigment to be added to the pigment-dispersed polyimide precursor composition is preferably from 1 to 300 parts by weight, more preferably from 1 to 300 parts by weight, from the viewpoint of the adhesion to the transparent substrate and the degree of coloring. The amount is preferably 50 to 150 parts by weight, but is not limited thereto.

As a method for dispersing the organic pigment, means such as a sand mill, a ball mill, an attritor, a three-roll mill, a kneader, and an ultrasonic disperser can be employed, but the method is not limited thereto.

The pigment dispersant used in the present invention includes:
For example, "Sol Sparse" 24000, 22000, 5
000 (manufactured by ICI), "Disparvic" 160,
161, 162, 163, 164 (manufactured by Big Chemie), "Dipalon" (manufactured by Kusumoto Kasei), "Aditol" (manufactured by Hoechst), or the number of repeating structural units represented by the general formula (1) is 10 or less. Can be used. Among these, the polyimide precursor is preferably used because of its excellent dispersion performance. Such a dispersant can be mixed at 0.01 to 200% by weight based on the pigment.

In the present invention, a surfactant can be added for the purpose of improving the coating property and leveling property of the pigment-dispersed polyimide precursor composition. In this case, the addition amount is 1000 pp from the viewpoint of reliability of display quality of a liquid crystal display element or the like.
m or less is preferable, but not limited to this.

The solid content concentration of the pigment-dispersed polyimide precursor composition of the present invention is preferably 1 to 50% by weight, more preferably 3 to 50%, from the viewpoint of uniformity of coating film thickness and coating performance.
20% by weight is good, but not limited thereto.

The rheological properties of the pigment-dispersed polyimide precursor composition of the present invention are preferably such that a Casson yield value τ ₀ , preferably 0.1 P
a, and more preferably 0.05 Pa or less. Ca
The Sson yield value τ ₀ is an evaluation criterion for pseudoplasticity, and is based on Casson's flow equation expressed by the following equation (1).
The yield value can be determined. S = shear rate, D = shear stress, τ ₀ = yield value, μ ₀ = Casson
When the viscosity, yield value is determined by the square of the y-intercept of the graph of S ^1/2 for D ^1/2 of the flow equation (1).

[0033]

(Equation 1) A method for forming a color filter using the thus obtained polyimide precursor composition of the present invention will be described by taking a color filter for a liquid crystal display element as an example. That is, a color filter for a liquid crystal display element is generally formed by laminating a resin black matrix, pixels, and a protective film in this order on a transparent substrate.

First, a black paste obtained by dispersing a light-shielding agent in a medium containing a polyimide precursor and a solvent as main components is applied on a transparent substrate. The transparent substrate is not particularly limited, and inorganic glass such as quartz glass, non-alkali glass, alkali glass whose surface is coated with silica, and organic plastic films or sheets are preferably used. As a coating method, besides dip coating, a roll coater, and a curtain flow, a rotary coating method such as a wicker or a spin coater is suitably used.

Thereafter, drying and semi-curing are performed using a hot air oven, a hot plate or the like. The semi-curing conditions are slightly different depending on the kind and the amount of the polyimide precursor used, but it is general that heating is usually performed at 100 to 180 ° C. for 1 to 60 minutes. If a non-photosensitive polyimide precursor is used, then apply a photoresist, pre-bake,
Exposure is performed using an optical mask. Then, using a developer,
The development of the resist and the patterning of the black matrix are successively performed by dip, shower, paddle method or the like. Thereafter, the resist is stripped by a dip, shower, paddle method, or the like using a stripper. Finally, to imidize, 2
This is heated at 00 to 400 ° C. for 1 to 60 minutes and cured. In addition, usually between 20 and 200 μm
The openings are provided to the extent that pixels are formed in this space in a later step.

Next, the above-mentioned photolithography method is repeated for the three colors using the pigment-dispersed polyimide precursor composition of the three colors of red, blue and green of the present invention, whereby the pixels of the three colors are formed in a black matrix. It is formed in the opening. The thickness of the pixel is preferably 0.5 to 3 μm from the viewpoint of reducing the surface step on the color filter.

Thereafter, a protective film is laminated as required.
Examples of the protective film include an acrylic resin, an epoxy resin, a silicone resin, and a polyimide resin.
It is not limited to these. Finally, a color filter can be formed by laminating and patterning the transparent electrode as necessary by a known method.

[0038]

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

(Production of Polyimide Precursor Solution 1)
', 4,4'-biphenyltetracarboxylic dianhydride 1
44.2 g was charged together with 525 g of γ-butyrolactone and 220 g of N-methyl-2-pyrrolidone, 95.1 g of 4,4′-diaminodiphenyl ether and bis (3-
6.2 g of (aminopropyl) tetramethyldisiloxane was added and reacted at 60 ° C. for 3 hours. After the reaction, the polymerization was stopped by cooling to room temperature without closing the molecular terminals, and a polyimide precursor solution 1 having a viscosity of 600 poise (25 ° C.) was obtained.

The average number of repetitions of the structural units in the obtained polyimide precursor solution 1 was 27.

(Production of Polyimide Precursor Solution 2)
', 4,4'-biphenyltetracarboxylic dianhydride 1
44.2 g was charged together with 772 g of γ-butyrolactone and 4,3′-diaminodiphenyl sulfone was 49.6.
g, 4,4 ′ diaminodiphenylmethane 54.5 g,
And 6.2 g of bis (3-aminopropyl) tetramethyldisiloxane were added and reacted at 60 ° C. for 3 hours.
After the reaction, 1.9 g of maleic anhydride was added.
After heating for a period of time to seal the molecular ends, the viscosity was 150 poise (2
5 ° C.) to obtain a polyimide precursor solution 2. The average value of the number of repetitions of the structural units in the obtained polyimide precursor solution 2 was 20.

(Production of Polyimide Precursor Solution 3)
', 4,4'-biphenyltetracarboxylic dianhydride 1
44.2 g was charged together with 525 g of γ-butyrolactone and 220 g of N-methyl-2-pyrrolidone, 95.1 g of 4,4′-diaminodiphenyl ether and bis (3-
6.2 g of (aminopropyl) tetramethyldisiloxane was added and reacted at 60 ° C. for 3 hours. After the reaction, 3.3 g of nadic anhydride was added, and the mixture was heated at 60 ° C. for 1 hour to seal the molecular terminals, thereby obtaining a polyimide precursor solution 3 having a viscosity of 300 poise (25 ° C.). The average value of the number of repetitions of the structural units in the obtained polyimide precursor solution 1 was 25.

(Production of Polyimide Precursor Solution 4)
', 4,4'-benzophenonetetracarboxylic dianhydride 72.5 g, pyromellitic dianhydride 49.1 g,
95.1 g of 4,4′-diaminodiphenyl ether, 6.2 g of bis-3- (aminopropyl) tetramethyldisiloxane, and 1015.4 g of γ-butyrolactone were charged and reacted at 60 ° C. for 3 hours. The average value of the number of repeating structural units of the obtained polyimide precursor solution 4 was 1
It was 0.

Example 1 10.1 g of Pigment Red 177, 2.5 g of Pigment Yellow 20, and 7.0 of polyimide precursor solution 4
g, 70.4 g of γ-butyrolactone was added to glass beads 90.
g at 7000 rpm using a homogenizer.
After the time dispersion, the glass beads were removed by filtration to obtain a pigment dispersion.

4.8 g of polyimide precursor solution 1, 4.8 g of polyimide precursor solution 2 and γ-butyrolactone 5
5.3 g, 3-methyl-3-methoxybutanol 6.6
g and 2.8 g of ethanol were mixed together to obtain a pigment dispersion 2
The resulting mixture was added to 5.7 g and mixed to obtain a pigment-dispersed polyimide precursor composition of the present invention. The viscosity of the obtained pigment-dispersed polyimide precursor composition was 25 centipoise, and the Casson yield value τ ₀ was 0.1 Pa or less. Further, when observed under a microscope, no aggregation of the pigment was observed, and the pigment was uniformly dispersed.

This pigment-dispersed polyimide precursor composition was applied onto an alkali-free glass substrate (OA-2, manufactured by Nippon Electric Glass Co., Ltd.) using a spin coater and semi-cured at 100 ° C. for 10 minutes to obtain a 1.2 μm-thick polyimide precursor. A colored film was obtained. On this film, a positive photoresist (OOH manufactured by Tokyo Ohkasha Co., Ltd.)
FPR-800) was applied and dried by heating at 80 ° C. for 20 minutes to obtain a 1 μm-thick resist film. Using an ultraviolet exposure machine (PLA-501F, manufactured by Canon Inc.), ultraviolet light having a wavelength of 365 nm and an intensity of 50 mJ / cm ² was irradiated through a photomask. After exposure, it is immersed in a developer of a 2.38% aqueous solution of tetramethylammonium hydroxide,
The development of the photoresist and the polyimide precursor colored film was performed simultaneously. After the etching, the unnecessary photoresist layer was stripped with methyl cellosolve acetate. Next, this was cured at 300 ° C. for 30 minutes to obtain a 1.0 μm-thick polyimide colored film.

The obtained polyimide colored film had no coating unevenness, and the etching property of the pixel was good.

Comparative Example 1 10.1 g of Pigment Red 177, 2.5 g of Pigment Yellow 20, and 70.4 g of γ-butyrolactone were dispersed in the same manner as in Example 1 to obtain a pigment dispersion. 9.6 g of polyimide precursor solution 2 and γ-butyrolactone 5
5.3 g, 3-methyl-3-methoxybutanol 6.6
g and 2.8 g of ethanol were mixed together to obtain a pigment dispersion 2
Then, the mixture was added to 5.7 g and mixed to obtain a pigment-dispersed polyimide precursor composition and a 1.0 μm-thick polyimide colored film in the same manner as in Example 1.

The resulting pigment-dispersed polyimide precursor composition had a viscosity of 50 centipoise and a Casson yield value τ.
₀ was 0.1 Pa or more, and when observed under a microscope, aggregation of the pigment was observed. Further, uneven coating was observed on the polyimide colored film.

Comparative Example 2 10.1 g of Pigment Red 177, 2.5 g of Pigment Yellow 20, and 70.4 g of γ-butyrolactone were dispersed in the same manner as in Example 1 to obtain a pigment dispersion. 9.6 g of polyimide precursor solution 1 and γ-butyrolactone 5
5.3 g, 3-methyl-3-methoxybutanol 6.6
g and 2.8 g of ethanol were mixed together to obtain a pigment dispersion 2
Then, the mixture was added to 5.7 g and mixed to obtain a pigment-dispersed polyimide precursor composition and a 1.0 μm-thick polyimide colored film in the same manner as in Example 1.

The resulting pigment-dispersed polyimide precursor composition had a viscosity of 40 centipoise and a Casson yield value τ
₀ was 0.1 Pa or more, and when observed under a microscope, aggregation of the pigment was observed. Further, uneven coating was observed on the polyimide colored film, and the etching properties of the pixels were also poor, and etching residues were observed.

Comparative Example 3 10.1 g of Pigment Red 177, 2.5 g of Pigment Yellow 20, and 7.0 of Polyimide Precursor Solution 4
g and 70.4 g of γ-butyrolactone were dispersed in the same manner as in Example 1 to obtain a pigment dispersion. Polyimide precursor solution 1
4.8 g, polyimide precursor solution 2 4.8 g, γ-
A solution prepared by mixing 58.1 g of butyrolactone and 6.6 g of 3-methyl-3-methoxybutanol was used as a pigment dispersion.
Then, the mixture was added to 7 g, and a pigment-dispersed polyimide precursor composition and a 1.0 μm-thick polyimide colored film were obtained in the same manner as in Example 1.

The resulting pigment-dispersed polyimide precursor composition had a viscosity of 25 centipoise and a Casson yield value τ.
₀ was 0.1 Pa or less, and when observed under a microscope, no aggregation of the pigment was observed and the pigment was uniformly dispersed. However, uneven coating was observed on the polyimide colored film.

Example 2 Pigment Green 7 (20.7 g), Pigment Yellow 20 (3.1 g), and γ-butyrolactone (66.2 g) were mixed with glass beads (90 g) using a homogenizer to obtain 70 g.
After dispersion at 00 rpm for 3 hours, the glass beads were removed by filtration to obtain a pigment dispersion.

4.3 g of polyimide precursor solution 3, 10.0 g of polyimide precursor solution 2, 48.8 g of γ-butyrolactone, 13.7 g of 3-methyl-3-methoxybutyl acetate, and 4.6 g of ethanol were mixed. The solution,
18.6 g of the pigment dispersion was added and mixed to obtain a pigment-dispersed polyimide precursor composition of the present invention.

The resulting pigment-dispersed polyimide precursor composition had a viscosity of 20 centipoise and a Casson yield value τ.
₀ was 0.1 Pa or less. Further, when observed under a microscope, no aggregation of the pigment was observed, and the pigment was uniformly dispersed.

This pigment-dispersed polyimide precursor composition was treated in the same manner as in Example 1 to obtain a 1.0 μm-thick polyimide colored film.

The obtained polyimide colored film had no coating unevenness, and the etching property of the pixel was also good.

Comparative Example 4 20.7 g of Pigment Green 7, 3.1 g of Pigment Yellow 20, and 66.2 g of γ-butyrolactone were dispersed in the same manner as in Example 2 to obtain a pigment dispersion. 14.3 g of polyimide precursor solution 2 and γ-butyrolactone 5
A solution obtained by mixing 3.4 g and 13.7 g of 3-methyl-3-methoxybutyl acetate was added to and mixed with 18.6 g of a pigment dispersion, and a pigment-dispersed polyimide precursor composition and a film were formed in the same manner as in Example 2. A 1.0 μm thick polyimide colored film was obtained.

The resulting pigment-dispersed polyimide precursor composition had a viscosity of 25 centipoise and a Casson yield value τ.
₀ was 0.1 Pa or more, and when observed under a microscope, aggregation of the pigment was observed. Further, uneven coating was observed on the polyimide colored film.

Comparative Example 5 20.7 g of Pigment Green 7, 3.1 g of Pigment Yellow 20, and 66.2 g of γ-butyrolactone were dispersed in the same manner as in Example 2 to obtain a pigment dispersion. 14.3 g of polyimide precursor solution 3 and γ-butyrolactone 4
A solution obtained by mixing 8.8 g, 13.7 g of 3-methyl-3-methoxybutyl acetate, and 4.6 g of ethanol was added to 18.6 g of the pigment dispersion, and mixed. Composition and thickness 1.0
A μm polyimide colored film was obtained.

In the obtained polyimide colored film, the etching property of the pixel was poor, and an etching residue was observed.

Example 3 6.9 g of Pigment Blue B-15: 6, 6.8 g of polyimide precursor solution 3 and 1 of polyimide precursor solution 2
5.9 g and 60.4 g of N-methyl-2-pyrrolidone were mixed with 90 g of glass beads using a homogenizer to obtain 10 g.
After dispersion at 000 rpm for 5 hours, the glass beads were removed by filtration to obtain a pigment dispersion. γ-butyrolactone 2
A solution obtained by mixing 9.1 g and 13.8 g of 3-methyl-3-methoxybutyl acetate was added to and mixed with 57.1 g of a pigment dispersion to obtain a pigment-dispersed polyimide precursor composition of the present invention.

The resulting pigment-dispersed polyimide precursor composition had a viscosity of 25 centipoise and a Casson yield value τ.
₀ was 0.1 Pa or less. Further, when observed under a microscope, no aggregation of the pigment was observed, and the pigment was uniformly dispersed.

This pigment-dispersed polyimide precursor composition was treated in the same manner as in Example 1 to obtain a 1.0 μm-thick polyimide colored film. The obtained polyimide colored film had no coating unevenness, and the etching property of the pixel was good.

Comparative Example 6 6.9 g of Pigment Blue B-15: 6, 22.7 g of the polyimide precursor solution 2 and 60.4 g of N-methyl-2-pyrrolidone were dispersed in the same manner as in Example 3 to obtain a pigment dispersion. A liquid was obtained. 29.1 g of γ-butyrolactone, 3-methyl-3
A solution obtained by mixing 13.8 g of -methoxybutyl acetate was added to and mixed with 57.1 g of the pigment dispersion, and a pigment-dispersed polyimide precursor composition and a 1.0 μm-thick polyimide colored film were obtained in the same manner as in Example 3. Was.

The resulting polyimide colored film showed uneven coating.

Comparative Example 7 6.9 g of Pigment Blue B-15: 6, 22.7 g of the polyimide precursor solution 3 and 60.4 g of N-methyl-2-pyrrolidone were dispersed in the same manner as in Example 3 to obtain a pigment dispersion. A liquid was obtained. 29.1 g of γ-butyrolactone, 3-methyl-3
A solution obtained by mixing 13.8 g of -methoxybutyl acetate was added to and mixed with 57.1 g of the pigment dispersion, and a pigment-dispersed polyimide precursor composition and a 1.0 μm-thick polyimide colored film were obtained in the same manner as in Example 3. Was.

The etching properties of the pixels of the obtained polyimide colored film were poor, and etching residues were observed.

[0070]

According to the present invention, it is possible to provide a color filter having no coating unevenness, a high contrast ratio and a flat coating film surface, and an excellent image can be obtained when incorporated in a liquid crystal display device. .

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location G09F 9/00 321 G09F 9/00 321D

Claims (10)

[Claims] 1. A polyimide resin comprising a polyimide resin, a solvent and a pigment as main components, wherein the polyimide resin is a polyimide precursor represented by the following general formula (1) and an organic group R ₁ represented by the general formula: And at least one selected from organic groups R ₂ contains at least two different precursors. Embedded image 2. The polyimide resin composition according to claim 1, wherein the polyimide precursor has a repeating unit of the structural unit of the general formula (1) of 10 or less. 3. The polyimide resin composition according to claim 1, wherein the composition contains the polyimide precursor whose molecular terminal is not sealed. 4. The composition according to claim 1, wherein the terminal of the molecule is maleic anhydride;
2. The method according to claim 1, wherein the polyimide precursor is sealed with at least one dicarboxylic anhydride selected from phthalic anhydride, succinic anhydride, and nadic anhydride.
The polyimide-based resin composition according to the above. 5. The polyimide resin composition according to claim 1, wherein said pigment is an organic pigment. 6. The polyimide resin composition according to claim 1, wherein said solvent contains at least one selected from amide polar solvents and lactone solvents. 7. The polyimide resin composition according to claim 6, wherein said solvent contains a solvent having a boiling point of 100 ° C. or lower. 8. The polyimide resin composition according to claim 1, wherein said composition has a rheological property having a Casson yield value τ ₀ of 0.1 Pa or less. 9. A color filter, wherein the polyimide resin composition according to any one of claims 1 to 8 is used for a light transmitting colored pattern formed on a transparent substrate. 10. A liquid crystal display device comprising the color filter according to claim 9.