JPH07209512A - Colored paste for color filter, color filter and its production - Google Patents

Abstract

PURPOSE:To obtain a color paste having red, green and blue uniform rheological characteristics and without causing uneven coloration due to sagging in coating and the wind in drying by specifying the yield value and non-Newtonian viscosity index of a transparent resin composition contg. pigment. CONSTITUTION:This transparent resin composition contains pigment and is a colored paste for a color filter. The yield value s0 and the non-Newtonian viscosity index (n) are >=0.1Pa and <=0.9 respectively, and are the evaluation criteria of the pseudoplasticity according to the Herschel-Berkeley's flow equation. When the shear rate is denoted by S, the shearing stress by D, the yield value by s0, the non-Newtonian viscosity index by (n) and the non-Newtonian viscosity coefficient by mu, the flow equation is shown by S=sO+muD<n>. As the non-Newtonian viscosity index (n) is lowered, the film applied is smoothed immediately after coating, and the leveling performance is improved. The sagging in coating is reduced as the yield value sO is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter color paste used for a liquid crystal display device, a solid-state image pickup device and the like, a color filter and a method for producing the same.

[0002]

2. Description of the Related Art Hitherto, as a method for forming a colored layer of a color filter, a dyeing method, a pigment dispersion method, an electrodeposition method, a printing method and the like have been known. Among these, as the coloring resin material used in the pigment dispersion method, organic / inorganic pigments are used as colorants.
Polyimide resin, polyvinyl alcohol (P
VA) resin, acrylic resin, epoxy resin and the like are known. Among them, the polyimide resin is useful as a color filter material because it has high heat resistance and high reliability, and has little discoloration in the film forming process of the transparent electrode and the heating process of the alignment film.

A method for forming a color filter having a pigment-dispersed polyimide as a coloring layer is usually as follows. First, an acid dianhydride and a diamino compound are reacted in a polar solvent to synthesize a polyamic acid polymer, and a pigment is dispersed in the polyamic acid polymer to obtain a colored color paste. This color paste is applied on a transparent substrate and semi-cured.
A resist is applied thereon, and after pattern exposure, alkali etching is performed to form a desired fine pattern. After removing the resist, post-baking is performed to close the imide group. After repeating these three RGB colors, a transparent protective film,
A transparent electrode is formed to form a color filter.

Since polyamic acid, which is a raw material for polyimide, has a high polarity, it can be dissolved only in a limited solvent such as N-methylpyrrolidone having a high polarity and a high boiling point or dimethylacetamide, and the degree of freedom in solvent selection is low. for that reason,
In the pigment dispersion, it is difficult to form an electrical or steric repulsive group on the surface of the pigment for stabilizing the dispersion, so that the pigments are agglomerated gently, and as a result, the color paste exhibits pseudoplasticity. When such a color paste is spin-coated with a spin coater, the film thickness of the portion where the normal stress is small at the center of rotation is increased. A dip coating method or a curtain flow coating method is suitable for such pseudo-plastic coating material. However, since the degree of agglomeration varies depending on the type of pigment, particularly with pastes using green and blue pigments, sagging occurred during dip application and color unevenness due to wind occurred during drying in an oven.

Further, the color filter obtained by using such a conventional color paste has insufficient hardness and is liable to be flawed in the manufacturing process.

[0006]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a colored paste for a pigment-dispersed color filter which has the same rheological properties of RGB (red, green, and blue) colors, and has no sagging during coating or drying. It is to provide a color paste that does not cause color unevenness due to wind. Another object of the present invention is to provide a color filter that uses a colored layer having a high surface hardness made of such a colored paste and further includes a transparent substrate and a transparent electrode. A further object of the invention is to provide a method of manufacturing such a color filter.

[0007]

That is, the object of the present invention is achieved by the following constitution. (1) A transparent resin composition containing a pigment, which has a yield value s0 of 0.1 Pa or more and a non-Newtonian viscosity index n of 0.9 or less. (2) A transparent resin composition containing a pigment, which contains fine particles of silicon oxide as an essential component. (3) A color filter including a transparent substrate, a colored layer, and a transparent electrode, wherein the colored layer is made of a transparent resin containing a pigment as a colorant, and contains silicon oxide fine particles as an essential component. The color filter to use. (4) When manufacturing a color filter including a transparent substrate, a colored layer and a transparent electrode, a transparent resin composition containing silicon oxide fine particles and a pigment as essential components is applied by a dip method to form a colored layer. And a method for manufacturing a color filter. (5) When manufacturing a color filter including a transparent substrate, a colored layer and a transparent electrode, a transparent resin composition containing silicon oxide fine particles and a pigment as essential components is applied by a curtain flow method to form a colored layer. A method for manufacturing a color filter, comprising:

The details of the present invention will be described below.

The transparent resin used in the present invention is not particularly limited, but a polyimide resin is preferably used. The polyimide resin reacts an acid dianhydride and a diamino compound in the presence of a solvent.

The acid dianhydride for synthesizing the polyimide resin is, for example, pyromellitic dianhydride, 3,3 ′,
4,4'-benzophenone tetracarboxylic dianhydride, 2,
2 ', 3,3'-benzophenone tetracarboxylic dianhydride,
3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 3,
3 ', 4,4'-diphenylsulfone tetracarboxylic acid dianhydride, 4,4'-oxydiphthalic acid dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,2,3,4- Examples thereof include cyclobutanetetracarboxylic dianhydride and 1,2,3,4-cyclopentanetetracarboxylic dianhydride.
Preferably, 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride, 2,2', 3,3'-benzophenone tetracarboxylic dianhydride, 3,3 ', 4,4'-biphenyl Tetracarboxylic acid dianhydride is used. These tetracarboxylic dianhydrides can be used in combination of two or more kinds.

Examples of the diamino compound for synthesizing the polyimide resin include 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 3,3′-diaminodiphenylmethane, 4 , 4'-Diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, paraphenylenediamine, metaphenylenediamine, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 1,4-bis (4-amino Examples thereof include phenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, and bis- (4-aminophenyl) tetramethyldisiloxane. Preferably 4,4 '
-Diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 3,3 '
-Using diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone and 3,3'-diaminodiphenylsulfone. These diamino compounds may be used in combination of two or more kinds. Further, in order to improve the adhesiveness with the substrate, it is also preferable to replace 1 to 8 mol% of the diamine with a diaminosiloxane compound. Examples of the diaminosiloxane compound include bis- (3-aminopropyl) tetramethyldisiloxane.

As a solvent for synthesizing the polyimide resin, a polar solvent is preferable mainly from the viewpoint of solubility. Examples of polar solvents are dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methyl-2-
Pyrrolidone, hexamethylphosphoramide, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, acetic acid ethylene glycol monomethyl ether, ethylene acetate Examples thereof include glycol monoethyl ether, ethylene glycol monobutyl ether acetate, γ-butyrolactone, and cyclohexanone. Preferably,
Dimethylacetamide, N-methyl-2-pyrrolidone,
Ethylene glycol monobutyl ether and γ-butyrolactone are used. These solvents may be used in combination of two or more. In addition, a solvent having a low boiling point such as methanol, ethanol or propanol can be added to improve the coating property and the drying property.

The pigments used in the present invention include organic pigments and inorganic pigments, and organic pigments are particularly preferable. R (red), G
In order to adjust the (green) and B (blue) filters to desired colors, yellow, orange and purple pigments may be mixed as auxiliary pigments with the main pigments red, green and blue pigments.

Examples of organic pigments include, for example, R-88,122,144,146,149,168,177,202,209,216 as red pigments,
As a yellow pigment Y-17,24,83,93,94,108,109,110,138,147
, G-7,36 as green pigment, B-15: 2,15: 3, as blue pigment
15: 4,15: 6, and V-19,23,32,37 and the like as purple pigments.

The pigment is usually contained in the transparent resin composition in a dispersed state.

The paste of the present invention has a yield value s0 of 0.
It is 1 Pa or more and the non-Newtonian viscosity index n is 0.
It must be 9 or less. The yield value s0 and the non-Newtonian viscosity index n are evaluation criteria for pseudoplasticity according to the Herschel Berkeley flow equation. S = shear rate, D
= Shear stress, s0 = yield value, n = non-Newtonian viscosity index, μ = non-Newtonian viscosity coefficient, the flow equation is expressed by S = s0 + μD ⁿ . In dip coating and curtain flow coating, the lower the non-Newtonian viscosity index n, the lower the viscosity at high shear rate, and the better the leveling performance for smoothing the film immediately after coating. Further, the higher the yield value s0 is, the less the sagging occurs in the dip coating, and the more the drying in the oven prevents the unevenness due to the wind. That is, the paint is required to satisfy these two parameters. The yield value s0 must be 0.1 Pa or more, preferably 0.3 Pa or more,
More preferably, it is 0.5 Pa or more. The yield value s0 is usually 5 Pa or less. The non-Newtonian viscosity index n is preferably 0.9 or less, more preferably 0.85 or less. The non-Newtonian viscosity index n is usually 0.1 or more.

The pigment concentration of the color paste of the present invention is 1w.
t% or more and 50 wt% or less is preferable and 2 wt% or more and 40
It is more preferably not more than wt%. If the concentration is less than 1%, it is difficult to coat the film to a predetermined thickness. On the other hand, if it exceeds 50%, the viscosity becomes too high, and the coating speed becomes slow, and coating defects are likely to occur.

The color filter color paste of the present invention having such a yield value s0 of 0.1 Pa or more and a non-Newtonian viscosity index n of 0.9 or less is obtained by, for example, adding silicon oxide fine particles to the color paste. It can also be obtained by doing.

As the silicon oxide fine particles used in the present invention, various kinds can be used, but those having a primary particle diameter of about 1 to 100 nm are preferably used. It is also possible to use dry silica fine particles and colloidal silica in which silicon oxide is previously dispersed in a solvent. Examples of the dry silicon oxide fine particles include "Aerosil" manufactured by Nippon Aerosil Co., Ltd., "Reorosil" manufactured by Soda Tokuyama, and the like. Examples of colloidal silica include "Snowtex" manufactured by Nissan Chemical Co., Ltd. and "Oscar" manufactured by Catalytic Chemical Co., Ltd.

The method for adding the silicon oxide fine particles is not particularly limited, but it is preferable to disperse the dry silica fine particles or colloidal silica in a solvent together with the pigment. It is also preferable to disperse dry silica fine particles or colloidal silica, a pigment and a polyimide resin together in a solvent. Further, the colloidal silica may be added at any time before and after the dispersion.

The content of silicon oxide fine particles is 100
Usually, 1 part by weight or more and 200 parts by weight or less are preferable with respect to parts by weight. More preferably, it is 10 parts by weight or more and 100 parts by weight or less.

In the present invention, the dispersion of the pigment and the silicon oxide fine particles in the transparent resin composition can be carried out by an ordinary method. For example, the dispersion method of the pigment and the silicon oxide fine particles is a sand mill, a ball mill, an attritor or a three roll mill. , Kneader, ultrasonic disperser and the like. Thus, the color filter color paste of the present invention is obtained.

Since the rheological properties of the color filter color paste of the present invention can be adjusted by the addition amount of the silicon oxide fine particles, the rheological properties of three colors of RGB (red, green, blue) can be made uniform, and further, at the time of coating. It is a color paste that does not cause pigment aggregation, dripping, or wind unevenness during drying. In particular, it is possible to effectively eliminate the drawback that color unevenness occurs due to pigment aggregation when applying green and blue pastes.

The color filter color paste of the present invention can be applied on a transparent substrate to form a color layer. As a method for forming the colored layer, in the present invention, preferably, dip coating (dip coating)
Alternatively, curtain flow type coating (curtain flow coating) is preferably used. The dip coating is a method in which the transparent substrate is dipped in a coloring paste and then smoothly pulled up to apply. Curtain flow coating is a method in which the coating material is discharged in a curtain shape from the lip tip of a die called a die head, a T die, or a slit die, and is applied to the substrate in a non-contact manner. The method of these dip coating and curtain flow coating is not particularly limited,
It can be performed by a conventional method. The obtained colored layer is
Since the fine particles of silicon oxide having a hardness higher than that of the binder resin are contained as the filler, the hardness of the obtained color filter is remarkably improved.

A color filter can be obtained by forming a transparent electrode on the thus-formed colored layer by a conventional method such as vapor deposition or sputtering. In addition,
It is also possible to form a protective film and a passivation film before forming the transparent electrode.

The transparent substrate and transparent electrode used in the present invention are not particularly limited, and a commonly used transparent substrate and transparent electrode can be used.

[0027]

The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

Reference Example 1 (Production of Polyamic Acid Polymer A) 3059 g of N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP) was weighed in a three-necked flask. To this, 346 g of 4,4′-diaminodiphenyl ether and 17.9 g of bis (3-aminopropyl) tetramethyldisiloxane (hereinafter abbreviated as SiDA) were added at 50 ° C. while stirring the solvent, and completely dissolved. Four,
When 4'-DAE is completely dissolved, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (hereinafter abbreviated as BPDA) 51
3.7g was added little by little and it was made to react at 50 degreeC for 3 hours. The viscosity of the resulting varnish was measured with an E-type viscometer manufactured by Tokyo Keiki Co., Ltd., and it was 94 poise at 25 ° C.

Reference Example 2 (Production of Polyamic Acid Polymer B) NMP769.2 g
Was weighed into a 3 neck 2L flask. To this, 59.5 g of 3,3'-diaminodiphenyl sulfone, 47.5 g of 4,4'-diaminodiphenylmethane, and 5.2 g of SiDA were added.
The solvent was added with stirring at 0 ° C. to completely dissolve it. When completely dissolved, 144.2 g of BPDA was added little by little and reacted at 50 ° C. for 3 hours. The viscosity of the resulting varnish was measured with an E-type viscometer manufactured by Tokyo Keiki Co., Ltd.
It was 110 poise at ° C.

Example 1 34.4 g of phthalocyanine blue (B-15: 6) and 3.8 g of dioxazine violet (V-23), 29.8 g of "Aerosil # 200" manufactured by Nippon Aerosil Co., Ltd. and NMP of 612 g were mixed, and then mixed in a sand mill. Dispersed for 1 hour. To 550 g of the obtained dispersion liquid, 265 g of the polyamic acid obtained in Reference Example 2, 485 g of NMP and 295 g of butyl cellosolve (hereinafter abbreviated as BC) were added and filtered to obtain a color paste. The viscosity of this product was measured with an R-type viscometer (manufactured by Toki Sangyo Co., Ltd.), and calculated from the Herschel Berkeley equation, the yield value was s0 = 0.310 Pa and the non-Newtonian viscosity index n = 0.701.

The resulting color paste was dip-coated on a transparent glass substrate to a film thickness of 1.2 μm, dried in an oven at 120 ° C. for 10 minutes, and then heat-cured at 300 ° C. for 30 minutes. The obtained coating film had the pigment uniformly dispersed and had a surface gloss. Further, as a result of visual observation under a monochromatic ray of a sodium lamp, no dripping or unevenness due to wind during drying was observed.

Example 2 The color paste obtained in Example 1 was curtain-flow coated on a transparent glass substrate to a film thickness of 1.2 μm, dried in an oven at 120 ° C. for 10 minutes, and then dried.
It was heat-cured at 30 ° C for 30 minutes. The obtained coating film had the pigment uniformly dispersed and had a surface gloss. Further, as a result of visual observation under a monochromatic ray of a sodium lamp, no unevenness due to wind during drying was observed.

Example 3 32.7 g of phthalocyanine blue (B-15: 6) and 3.6 g of dioxazine violet (V-23), 23.7 g of "Aerosil # 200" manufactured by Nippon Aerosil Co., Ltd., and 540 g of NMP were mixed, and a sand mill was used. Dispersed for 1 hour. 530 g of the obtained dispersion liquid, 359 g of the polyamic acid obtained in Reference Example 2, 732 g of NMP, and 264 g of BC.
Was added and filtered to obtain a color paste. The viscosity of this product was measured with an R-type viscometer (manufactured by Toki Sangyo Co., Ltd.) and calculated from the Herschel Berkeley equation, yield value s0 = 0.17
It was 2 Pa and the non-Newtonian viscosity index n = 0.833.

The resulting color paste was dip-coated on a transparent glass substrate to a film thickness of 1.2 μm, dried in an oven at 120 ° C. for 10 minutes, and then heat-cured at 300 ° C. for 30 minutes. The obtained coating film had the pigment uniformly dispersed and had a surface gloss. Further, as a result of visual observation under a monochromatic ray of a sodium lamp, no dripping or unevenness due to wind during drying was observed.

Example 4 22.4 g of brominated phthalocyanine green (G-36)
And Disazo Yellow (Y-83) 4.9 g, Nippon Aerosil "Aerosil # 200" 7.9 g and NM
P184 g was mixed and dispersed by a sand mill for 1 hour. To 210 g of the obtained dispersion liquid, 157 g of the polyamic acid obtained in Reference Example 1, 297 g of NMP and 149 g of BC were added and filtered to obtain a color paste. The viscosity of this product was measured with an R-type viscometer (manufactured by Toki Sangyo), and calculated from the Herschel Berkeley equation, the yield value s0 = 0.325Pa
And the non-Newtonian viscosity index n = 0.718.

The resulting color paste was dip-coated on a transparent glass substrate to a film thickness of 1.2 μm, dried in an oven at 120 ° C. for 10 minutes, and then heat-cured at 300 ° C. for 30 minutes. The obtained coating film had the pigment uniformly dispersed and had a surface gloss. Further, as a result of visual observation under a monochromatic ray of a sodium lamp, no dripping or unevenness due to wind during drying was observed.

Example 5 8.3 g of dianthraquinone red (R-177) and 3.6 g of disazo yellow (Y-83), 1.2 g of "Aerosil # 200" manufactured by Nippon Aerosil and NMP15
After dispersing 8 g by a sand mill for 1 hour, the polyamic acid 5 obtained in Reference Example 1 was added to 155 g of the obtained dispersion.
1.7 g, NMP126 g, and BC55 g were added and filtered to obtain a color paste. The viscosity of this product was measured with an R-type viscometer (manufactured by Toki Sangyo Co., Ltd.) and calculated from the Herschel Berkeley equation, yield value s0 = 0.436 Pa,
The non-Newtonian viscosity index n = 0.562.

The obtained color paste was dip-coated on a transparent glass substrate to a film thickness of 1.2 μm, dried in an oven at 120 ° C. for 10 minutes, and then heat-cured at 300 ° C. for 30 minutes. The obtained coating film had the pigment uniformly dispersed and had a surface gloss. Further, as a result of visual observation under a monochromatic ray of a sodium lamp, no dripping or unevenness due to wind during drying was observed.

Example 5 The green paste obtained in Example 4 was dip-coated on a transparent glass substrate to a film thickness of 1.2 μm and dried in an oven at 120 ° C. for 10 minutes. A positive photoresist was spin-coated on it and dried on a hot plate at 100 ° C. for 10 minutes. After exposing it with a high pressure mercury lamp with a predetermined mask on it, etching with an alkaline aqueous solution,
The resist was peeled off with butyl acetate and heat-cured at 300 ° C. for 30 minutes to form a G pixel. Subsequently, the red paste obtained in Example 5 and the blue paste obtained in Example 1 were similarly patterned to form RGB pixels. An ITO transparent electrode was formed thereon by sputtering to a thickness of 1200 Å to obtain a color filter.
This color filter had a hard surface hardness. Furthermore, when a color liquid crystal display device was assembled using this color filter, a good liquid crystal display device without flaws was obtained.

Comparative Example 1 29.0 g of brominated phthalocyanine green (G-36)
And Disazo Yellow (Y-83) 6.4 g and N
MP186g was mixed and dispersed by a sand mill for 1 hour.
To 210 g of the obtained dispersion liquid, 240 g of the polyamic acid obtained in Reference Example 1, 439 g of NMP and 141 g of BC were added and filtered to obtain a color paste. The viscosity of this product was measured with an R-type viscometer (manufactured by Toki Sangyo), and calculated from the Herschel Berkeley equation, the yield value s0 = 0.065P
and a non-Newtonian viscosity index n = 0.91.

The obtained color paste was dip-coated on a transparent glass substrate to a film thickness of 1.2 μm, dried in an oven at 120 ° C. for 10 minutes, and then heat-cured at 300 ° C. for 30 minutes. As a result of visually observing the obtained coating film under a monochromatic light beam of a sodium lamp, unevenness of sagging occurred, and unevenness due to wind during drying was so severe that it could not be used as a color filter.

Comparative Example 2 S-BEN (manufactured by Toyojun Yoko) which is an organic bentonite rheology modifier in place of Aerosil in Example 1
A coated film was obtained in exactly the same manner except that was added.
As a result of visual observation of the obtained coating film, the pigment was agglomerated severely and had no surface gloss, so that it could not be used as a color filter.

[0043]

Since the color paste of the present invention can adjust the rheological characteristics, it is possible to match the characteristics of RGB, and in dip coating and curtain flow coating, a coating film free from color unevenness due to dripping or wind during drying can be formed. Obtainable. Further, the color filter according to the present invention,
Since the hardness is remarkably improved, it is possible to provide a more industrially practical color filter and its manufacturing method.

Claims (5)

[Claims] 1. A coloring material for a color filter, which is a transparent resin composition containing a pigment and has a yield value s0 of 0.1 Pa or more and a non-Newtonian viscosity index n of 0.9 or less. paste. 2. A colored resin-containing paste for a color filter, which is a transparent resin composition containing a pigment and contains silicon oxide fine particles as an essential component. I 3. A color filter der that includes a transparent substrate and a colored layer and a transparent electrode, said colored layer comprises a transparent resin and a coloring agent a pigment, and containing silicon oxide fine particles as essential components Is a color filter. 4. When manufacturing a color filter comprising a transparent substrate, a colored layer and a transparent electrode, a transparent resin composition containing silicon oxide fine particles and a pigment as essential components is applied by a dip method to form a colored layer. A method of manufacturing a color filter, comprising: 5. When producing a color filter comprising a transparent substrate, a colored layer and a transparent electrode, a transparent resin composition containing silicon oxide fine particles and a pigment as essential components is applied by a curtain flow method to form a colored layer. A method for manufacturing a color filter, which comprises forming the color filter.