JP2811675B2 - Heat-resistant coloring paste for color filters - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heat-resistant colored paste for a color filter used for a liquid crystal display, an imaging device, and the like.

[Prior art] Conventionally, as a heat-resistant coloring paste for a color filter,
3,3 ', 4,4 with excellent heat resistance, transparency, pattern processing
4'-biphenyltetracarboxylic dianhydride and 3,3'-
A polyimide precursor varnish polymerized from (or 4,4'-) diaminodiphenyl sulfone in which an organic pigment having high heat resistance is dispersed has been proposed (JP-A-60-184202).
JP, JP-A-60-184203).

[Problem to be Solved by the Invention] 3,3 ', 4,4'-Biphenyltetracarboxylic dianhydride and 3,3'-(or 4,3'-
The polyimide precursor polymerized from 4 '-) diaminodiphenyl sulfone is excellent in heat resistance, transparency, and pattern processability but has poor solvent resistance. Therefore, a color filter is prepared using a heat-resistant colored paste using this polyimide precursor. When manufacturing, the manufacturing conditions, for example, the thickness of the color filter, the coating solvent for the photoresist, the pattern processing conditions, the resist stripping agent, etc. are limited, the process tolerance is very narrow, and even a little outside this condition, There is a problem that cracks occur in the color filter layer to cause cloudiness and the like, and the transparency is greatly reduced.

An object of the present invention is to solve the above-mentioned drawbacks and to provide a heat-resistant coloring paste which is excellent in heat resistance, transparency, pattern processability and solvent resistance and has a wide process tolerance.

[Means for Solving the Problems] An object of the present invention is to provide a heat-resistant colored paste for a color filter comprising a polyimide precursor, a solvent and a pigment, wherein the polyimide precursor is 3,3 ′, 4,4′- Biphenyltetracarboxylic dianhydride and 3,3'- (or 4,4'-)
Diaminodiphenyl sulfone and 1,3-bis (3-aminophenoxy) benzene, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, metaphenylenediamine, 3,3'-diaminodiphenyl ether, 4,4'- It is polymerized from one or more diamine compounds selected from the group consisting of diaminodiphenyl ethers, and 3,3 '-(or 4,4'-) diaminodiphenylsulfone accounts for 30 moles of all diamine components. % To 70
It is achieved by a heat-resistant coloring paste for a color filter, which is characterized in that it is mol%.

The polyimide precursor in the present invention is 3,3 ', 4,4'
-Biphenyltetracarboxylic dianhydride (hereinafter abbreviated as BPDA), 3,3 '-(or 4,4'-) diaminodiphenylsulfone (hereinafter abbreviated as DDS) and 1,3-bis (3-aminophenoxy) benzene 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, metaphenylenediamine, 3,3'-diaminodiphenylether,
It is polymerized from one or more diamine compounds selected from the group consisting of 4,4'-diaminodiphenyl ether (hereinafter referred to as a third component). Here, the polyimide precursor can be a polyimide having an imide ring by heating or an appropriate catalyst.

3,3'- (or 4,4'-) which is an essential diamine component
The content of DDS is preferably from 30 mol% to 70 mol% based on all the diamine components contained in the polyimide precursor.

3,3'- (or 4,4'-) DDS content is 30 mol%
If the amount is less than 3,3′- (or 4,4′-) DDS component, transparency and pattern processability are extremely lowered, which is not preferable. Not improved.

Further, the polyimide precursor may be copolymerized with an aliphatic diamine having a siloxane structure within a range that does not reduce the heat resistance of the polyimide in order to improve the adhesiveness. Preferred specific examples include bis (3-aminopropyl) tetramethyldisiloxane. The copolymerization amount of the aliphatic diamine is 1 to 5 of the total diamine component.
Molar% is preferred from the viewpoint of heat resistance.

Further, the diamine component introduced as the third component has a nuclear substituent such as an amino group, an amide group, a carboxyl group, a sulfonamide group, and a methyl group within a range that does not adversely affect the heat resistance of the polyimide. Is also good.

When two or more third components are used, the mixing ratio of each component is not particularly limited, and can be arbitrarily selected within a range satisfying the above-described mixing conditions.

Particularly preferred examples of the combination of the polyimide precursors in the present invention include BPDA, 3,3 '-(or 4,4'-) DDS and 1,3-bis (3
-Aminophenoxy) benzene and bis (3-aminopropyl) tetramethyldisiloxane, BPDA and 3,3 '-(or 4,4'-) DDS and 3,3 '-(or 4,4'-) diaminodiphenylmethane And screws (3
-Aminopropyl) tetramethyldisiloxane, BPDA and 3,3 '-(or 4,4'-) DDS and 3,3 '-(or 4,4'-) diaminodiphenyl ether and bis (3-aminopropyl) tetra But not limited thereto.

The solvent used in the present invention is preferably a polar solvent from the viewpoint of solubility of the polyimide precursor.

As specific examples, dimethylsulfoxide, dimethylformamide, N-methyl-2-pyrrolidone, dimethylacetamide, hexamethylphosphoramide and the like are preferably used.

Further, in order to improve the dispersibility of the pigment and the coating properties of the heat-resistant coloring paste, a part of the polar solvent may be replaced with a solvent such as a hydrocarbon, an ester, or a higher alcohol.

As the pigment used in the present invention, an organic pigment is used, and a pigment having high transparency, excellent light resistance, heat resistance, and chemical resistance is preferably used. The amount of the pigment added to the polyimide precursor is 10 g to 30 g, and preferably 20 g to 150 g, based on 100 g of the polyimide precursor. When the amount of the pigment added is less than 10 g, sufficient performance is not obtained at a commonly used color filter film thickness of 0.5 μm to 5.0 μm, and 300 g
If the amount exceeds the range, it becomes difficult to uniformly disperse the pigment, and the film-forming ability is impaired.

Representative examples of the organic pigments that can be used in the present invention are represented by a color index (CI) number. For yellow pigments, CI Pigment Yellow 24, CI Pigment Yellow 83, CI Pigment Yellow 93, CI Pigment Yellow 94, and CI Pigment Yellow 147 .

For orange pigments, CI Pigment Orange 13, CI
Pigment Orange 36, CI Pigment Orange 43, C.I.
I. Pigment Orange 61, CI Pigment Orange 64,
CI Pigment Orange 65.

Red pigments include CI Pigment Red 48, CI Pigment Red 144, CI Pigment Red 166, CI Pigment Red 177, CI Pigment Red 216, and CI Pigment Red 224.

For purple pigments, CI Pigment Violet 19, CI Pigment Violet 23, CI Pigment Violet
32, CI Pigment Violet 37.

As blue pigments, CI Pigment Blue 15, CI Pigment Blue 15: 3, CI Pigment Blue 15: 4, CI Pigment Blue 15: 6, CI Pigment Blue 60.

Green pigments include CI Pigment Green 7 and CI Pigment Green 36.

 Examples of black pigments include C.I. Pigment Black 7.

In addition to the components comprising the polyimide precursor, solvent and pigment, the performance as a color filter, as long as the heat resistance is not significantly impaired, a surfactant, an adhesion improver, etc. may be added in small amounts as necessary. . As a surfactant, for example, "Fluorard" FC-430 (manufactured by 3M), and as an adhesion improver, S
H-430 (manufactured by Toray Silicone Co., Ltd.) is a specific example.

Next, a method for producing the heat-resistant paste for a color filter of the present invention will be described.

The whole amount of the diamine component is added and dissolved in a solvent (eg, dimethylacetamide) heated to about 50 ° C. while stirring. Next, BPDA is added and polymerized to synthesize a polyamic acid having a predetermined composition.

Next, an organic pigment is added to the obtained polyamic acid, and the pigment is dispersed using a three-roll, sand grinder or the like,
A desired heat-resistant colored paste for a color filter is obtained.

The heat resistance of the colored paste for a color filter of the present invention means that heat treatment at 300 ° C. for 20 minutes or more is possible.

[Action] As described above, BPDA and 3,3'- (or 4,4'-)
Colored paste formed from a polyimide precursor varnish containing DDS as a main component has excellent heat resistance, transparency, and pattern processability, but has poor solvent resistance and is extremely process-tolerant when actually assembled in a manufacturing process. Was narrow. On the other hand, according to the present invention, by replacing a specific amount of the 3,3′- (or 4,4′-) DDS with a specific diamine component having excellent solvent resistance and transparency, heat resistance, It has become possible to produce a polyimide precursor having a good balance of transparency, pattern processability and solvent resistance.

[Effects of the Invention] By using the heat-resistant coloring paste of the present invention, it has become possible to produce a filter having no transparency and particularly having high transparency in a blue filter. Further, since the solvent resistance was greatly improved, the allowable range of the process in the manufacturing process was widened, and the production efficiency was significantly improved.

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.

Example 1 N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP) solvent 1
286.5 g was weighed into a 3 l three-necked flask, and the 3,3′-D
119.2 g of DS and 140.3 g of 1,3-bis (3-aminophenoxy) benzene (hereinafter abbreviated as APB) were added at 50 ° C. while stirring the solvent, and completely dissolved. Next, 282.0 g of BPDA was added little by little and reacted. After reacting at 50 ° C for 5 hours, BPDA (10
(0 mol%), 3,3'-DDS (50 mol%) and APB (50 mol%) to obtain a polyamic acid varnish. The viscosity at this time was measured with an E-type viscometer manufactured by Tokyo Keiki Co., Ltd.
It was 6 poise / 25 ° C.

100 g of this varnish was weighed into a 250 cc beaker, and phthalocyanine blue (CI pigment blue 15: 4) powder 10.5
g and dioxazine violet (CI Pigment Violet 23) powder 4.5 g were added and kneaded well with a three-roll mill. 185 g of NMP was further added to the colored varnish, and the mixture was stirred well to obtain a colored paste.

Example 2 1511.5 g of NMP, 119.2 g of 3,3'-DDS, 95.2 g of 4,4'-diaminodiphenylmethane (hereinafter abbreviated as 4,4'-DAM) and BPD
A A varnish consisting of BPDA (100 mol%), 3,3'-DDS (50 mol%) and 4,4'-DAM (50 mol%) was obtained from 282.5 g in the same manner as in Example 1. Was. At this time, the viscosity was 181 poise / 25 ° C.

100 g of this varnish was weighed into a 250 cc beaker, and phthalocyanine blue (CI pigment blue 15: 4) powder 8.75
g and dioxazine violet (CI Pigment Violet 23) powder (3.75 g) were added and kneaded well with a three-roll mill. 140 g of NMP was further added to the colored varnish and stirred well to obtain a colored paste.

Example 3 1552.4 g of NMP, 149.0 g of 3,3'-DDS, 80.1 g of 4,4'-diaminodiphenyl ether (hereinafter abbreviated as 4,4'-DAE) and B
From 288.34 g of PDA, in the same manner as in Example 1, BPDA (100 mol%), 3,3'-DDS (60 mol%) and 4,4'-DAE (40 mol%)
Mol%). At this time, the viscosity was 280 poise / 25 ° C.

100 g of this varnish was weighed into a 250 cc beaker, and phthalocyanine blue (CI pigment blue 15: 4) powder 8.75
g and dioxazine violet (CI Pigment Violet 23) powder 3.75 g were added and kneaded well with a three-roll mill. 140 g of NMP was further added to the colored varnish and stirred well to obtain a colored paste.

Comparative Example From 1266 g of NMP, 248.31 g of 3,3'-DDS and 288.34 g of BPDA, in the same manner as in Example 1, BPDA (100 mol%) and 3,3'-
A varnish consisting of DDS (100 mol%) was obtained. At this time, the viscosity was 188 poise / 25 ° C.

100 g of this varnish was weighed into a 250 cc beaker, and phthalocyanine blue (CI pigment blue 15: 4) powder 10.5
g and 4.5 g of dioxazine violet (CI Pigment Violet 23) powder were added and kneaded well with a three-roll mill. 185 g of NMP was further added to the colored varnish, and the mixture was stirred well to obtain a colored paste.

The following evaluation tests were performed using the colored pastes obtained in Examples 1 to 3 and Comparative Examples.

(Permeability measurement) The prepared colored paste was bar-coated on a Pyrex glass plate of 5 cm x 5 cm and 1.1 mm in thickness, and heated at 150 ° C for 30 minutes and 3 minutes.
After heating at 00 ° C. for 30 minutes, a colored film having a film thickness of 1.0 μm ± 0.2 μm was prepared, and its spectral characteristics were measured using a spectrophotometer. The results are shown in Table 1.

(Solvent resistance test) A sample was prepared in the same manner as described above. However, the film thickness was 2.0 μm ± 0.2 μm. After immersing each sample in NMP and acetone for 60 minutes and 5% NaOH for 10 minutes at room temperature, the surface was observed using an optical microscope. The results are shown in Table 1.

(Heat resistance test) Using the sample used for the transmittance measurement, a standing test was performed in air and nitrogen at 250 ° C. for 2 hours, and the spectral transmittance was examined. Was.

(Pattern processing) Pattern processing was performed using a positive photoresist according to a conventional method, and microscopic observation was performed. In Examples 1 and 2 that satisfied the present invention, both samples had sharp edges. It had been. However, in the case of the comparative examples, cracks occurred in the positive photoresist stripping step in each case.

As is clear from Table 1, the colored paste of the present invention has excellent solvent resistance while maintaining good transmittance, heat resistance and workability as compared with the colored paste of the comparative example.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-184203 (JP, A) JP-A-61-254905 (JP, A) JP-A-61-254906 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) G02B 5/20

Claims (1)

(57) [Claims] 1. A heat-resistant color paste for a color filter comprising a polyimide precursor, a solvent and a pigment, wherein the polyimide precursor comprises 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride and 3,3 '-(Or 4,4'-) diaminodiphenylsulfone and 1,3-bis (3-aminophenoxy) benzene, 3,3'-diaminodiphenylmethane,
4'-diaminodiphenylmethane, metaphenylenediamine, 3,3'-diaminodiphenylether, polymerized from one or more diamine compounds selected from the group consisting of 4,4'-diaminodiphenylether,
A heat-resistant coloring paste for color filters, characterized in that 3,3 '-(or 4,4'-) diaminodiphenylsulfone accounts for 30 mol% to 70 mol% of all diamine components.