JP3933773B2 - Insulating agent for active matrix liquid crystal display elements - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a material for obtaining an insulating film for an active matrix liquid crystal display element, and more particularly to an insulating material for an active matrix liquid crystal display element having an extremely low dielectric constant and a high transmittance.
[0002]
[Prior art]
Liquid crystal displays (LCDs) are widely used as thin and low power consumption displays. In particular, TFT liquid crystal displays (TFT-LCDs), which are active matrix LCDs using thin film transistors (TFTs), are often used for applications that require high-definition display.
[0003]
On the substrate (TFT substrate) on which the TFT, which is one of the substrates with a transparent electrode constituting the TFT-LCD, is formed, wiring for sending a display signal to the transparent electrode and wiring for switching the TFT are orthogonally crossed vertically and horizontally. The transparent electrode which is provided in a stitch shape and is a display part is surrounded by these wirings. Therefore, in the peripheral part of the transparent electrode, the liquid crystal is aligned in a different direction from the central part due to the influence of the electric field by the wiring, and it is necessary to shield this part. The opening) could not be made sufficiently large.
[0004]
On the other hand, a method of providing a transparent interlayer insulating film between the wiring on the TFT substrate and between the TFT and the transparent conductive film for display has been studied. Since the transparent electrode and the wiring can have a sufficient distance in the thickness direction due to the interlayer insulating film, the alignment defect as described above does not occur and the opening can be widened.
[0005]
After forming the insulating film, it is necessary to sufficiently flatten the unevenness of the original substrate, such as TFT, because of the need to form a transparent electrode thereon. Therefore, since heat resistance, smoothness, and insulation are excellent, it is considered to apply a polyimide resin used as an insulator in a semiconductor.
[0006]
On the other hand, other required characteristics of the TFT-LCD insulating film are as follows: (1) High transmittance, (2) Dielectric constant at 1 MHz is 3 or less, (3) Low temperature firing at 250 ° C. or less which is the heat resistance temperature of the color filter , Etc.
[0007]
On the other hand, the film after baking of the conventional polyimide-type resin is generally colored in dark color, and there are few things which were excellent in the light transmittance of the short wavelength range around 400 nm. Although there are several excellent dielectric constants, the firing temperature is generally 350 ° C. or higher. For the above reasons, it has been difficult to apply to an insulating film for TFT-LCD.
[0008]
[Problems to be solved by the invention]
The present invention solves the problems of the polyimide resin composition as described above, and provides an insulating agent for a liquid crystal display element that has excellent insulation at a low baking temperature of 250 ° C. or less and has high transmittance. Is.
[0009]
[Means for Solving the Problems]
The present invention
[1] An insulating material for an active matrix liquid crystal display element comprising, as a resin component, a polyimide having a repeating unit represented by the general formula (1), wherein X and / or Y in the formula is an organic group having at least one fluorine. Yes,
[0010]
[Chemical 1]
(In the formula, X represents a tetravalent organic group, and Y represents a divalent organic group.)
[0011]
[2] X is the formula (2), (3), (4), (5), (6), (7), (8), (9), (10) and / or (11) [ 1] An insulating material for an active matrix liquid crystal display element comprising the polyimide described in [1] as a resin component,
[0012]
[Chemical 2]
[0013]
[Chemical 3]
[0014]
[Formula 4]
[0015]
[Chemical formula 5]
[0016]
[Chemical 6]
[0017]
[Chemical 7]
[0018]
[Chemical 8]
[0019]
[Chemical 9]
[0020]
[Chemical Formula 10]
[0021]
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[0022]
[3] An insulating material for an active matrix liquid crystal display element comprising a polyimide as a resin component according to [1], wherein Y is a formula (12), (13) and / or (14).
[0023]
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[0024]
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[0025]
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[0026]
The insulating agent for an active matrix display element of the present invention is a resin composition containing the general formula (1) and a polar organic solvent as components.
[0027]
Examples of the solvent of the general formula (1) include, but are not limited to, N-methyl-2-pyrrolidone, γ-butyrolactone, dimethylacetamide, N-vinyl-2-pyrrolidone, dimethyl sulfoxide and the like.
[0028]
The resin component in the present invention is a polyimide resin such as polyamic acid, polyamic acid ester which is a polyimide precursor, and solvent-soluble polyimide, but an epoxy resin or the like may be mixed or an inorganic filler may be added. .
[0029]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates a detail, this invention is not limited at all by these Examples.
[0030]
(Synthesis Example 1) 2,2-bis (3-amino-4-methylphenyl) hexafluoropropane in a four-necked separable flask equipped with a thermometer, a stirrer, a raw material inlet, and a dry nitrogen gas inlet tube 8 g (0.10 mol) is dissolved in 256.9 g N-methyl-2-pyrrolidone (NMP). To this system, 19.8 g (0.10 mol) of butanetetracarboxylic dianhydride was charged from the raw material charging port, and stirring was continued for 5 hours under flowing nitrogen while keeping the temperature of the system at 10 ° C. The temperature of the system was returned to room temperature, and stirring was further continued for 3 hours to obtain an NMP solution of polyamic acid. Add 60 g of toluene to the system, remove the dropping funnel and replace it with a Dean starch reflux condenser to raise the temperature of the system. Toluene is refluxed to carry out dehydration and imidization reaction. When the generation of moisture is completed, the temperature of the system is returned to room temperature, and dropped into 20 times amount of methanol to recover the solid content of polyimide. The solid content was dried with a vacuum dryer for 24 hours, and then dissolved in γ-butyrolactone so that the resin component concentration was 10% to obtain a polyimide solution (1).
[0031]
Synthesis Example 2 2,2-bis (3-amino-4-methylphenyl) hexafluoropropane in a four-necked separable flask equipped with a thermometer, stirrer, raw material inlet, and dry nitrogen gas inlet tube 8 g (0.10 mol) is dissolved in 312.8 g of N-methyl-2-pyrrolidone (NMP). To this system, 44.4 g (0.10 mol) of 2,2-bis (3,4-anhydrodicarboxyphenyl) hexafluoropropane was introduced from the raw material inlet, and nitrogen was maintained while maintaining the temperature of the system at 10 ° C. Stirring was continued for 5 hours under inflow. The temperature of the system was returned to room temperature, and stirring was further continued for 3 hours to obtain an NMP solution of polyamic acid. Add 60 g of toluene to the system, remove the dropping funnel and replace it with a Dean starch reflux condenser to raise the temperature of the system. Toluene is refluxed to carry out dehydration and imidization reaction. When the generation of moisture is completed, the temperature of the system is returned to room temperature, and dropped into 20 times amount of methanol to recover the solid content of polyimide. The solid content was dried with a vacuum dryer for 24 hours, and then dissolved in γ-butyrolactone so that the resin component concentration was 10% to obtain a polyimide solution (2).
[0032]
Synthesis Example 3 2,2-bis (3-amino-4-methylphenyl) hexafluoropropane 44. in a four-necked separable flask equipped with a thermometer, stirrer, raw material inlet, and dry nitrogen gas inlet tube. 4 g (0.10 mol) is dissolved in 240.9 g N-methyl-2-pyrrolidone (NMP). To this system, 26.4 g (0.10 mol) of 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride was charged from the raw material charging port, While maintaining the temperature of the system at 10 ° C., stirring was continued for 5 hours under nitrogen flow. The temperature of the system was returned to room temperature, and stirring was further continued for 3 hours to obtain an NMP solution of polyamic acid. Add 60 g of toluene to the system, remove the dropping funnel and replace it with a Dean starch reflux condenser to raise the temperature of the system. Toluene is refluxed to carry out dehydration and imidization reaction. When the generation of moisture is completed, the temperature of the system is returned to room temperature, and dropped into 20 times amount of methanol to recover the solid content of polyimide. The solid content was dried by a vacuum dryer for 24 hours, and then dissolved in γ-butyrolactone so that the resin component concentration was 10% to obtain a polyimide solution (3).
[0033]
(Synthesis Example 4) In a four-necked separable flask equipped with a thermometer, a stirrer, a raw material inlet, and a dry nitrogen gas inlet tube, 32.0 g (0.10 mol) of 2,2′-bis (trifluoromethyl) benzidine Is dissolved in 305.6 g of N-methyl-2-pyrrolidone (NMP). To this system, 44.4 g (0.10 mol) of 2,2-bis (3,4-anhydrodicarboxyphenyl) hexafluoropropane was introduced from the raw material inlet, and nitrogen was maintained while maintaining the temperature of the system at 10 ° C. Stirring was continued for 5 hours under inflow. The temperature of the system was returned to room temperature, and stirring was further continued for 3 hours to obtain an NMP solution of polyamic acid. Add 60 g of toluene to the system, remove the dropping funnel and replace it with a Dean starch reflux condenser to raise the temperature of the system. Toluene is refluxed to carry out dehydration and imidization reaction. When the generation of moisture is completed, the temperature of the system is returned to room temperature, and dropped into 20 times amount of methanol to recover the solid content of polyimide. The solid content was dried with a vacuum dryer for 24 hours, and then dissolved in γ-butyrolactone so that the resin component concentration was 10% to obtain a polyimide solution (4).
[0034]
(Synthesis Example 5) 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl- in a four-necked separable flask equipped with a thermometer, a stirrer, a raw material inlet, and a dry nitrogen gas inlet tube 26.42 g (0.10 mol) of 3-cyclohexene-1,2-dicarboxylic anhydride is dispersed in 300 g of N-methyl-2-pyrrolidone (NMP). To this system, 41.05 g (0.10 mol) of 2,2-bis [4,4 ′-(4-aminophenoxy) phenyl] propane was charged from the raw material inlet, and the temperature of the system was maintained at 10 ° C. Stirring was continued for 5 hours under nitrogen flow. The temperature of the system was returned to room temperature, and stirring was further continued for 3 hours to obtain an NMP solution of polyamic acid. Add 60 g of toluene to the system, remove the dropping funnel and replace it with a Dean starch reflux condenser to raise the temperature of the system. Toluene is refluxed to carry out dehydration and imidization reaction. When the generation of moisture is completed, the temperature of the system is returned to room temperature, and dropped into 20 times amount of methanol to recover the solid content of polyimide. The solid content was dried by a vacuum dryer for 24 hours, and then dissolved in γ-butyrolactone so that the resin component concentration was 10% to obtain a polyimide solution (5).
[0035]
(Example 1) The polyimide solution obtained in Synthesis Example 1 was applied to an aluminum plate having a thickness of 100 µm by spin coating and baked at 250 ° C to form a 10 µm polyimide film. Thereafter, the dielectric constant of this aluminum plate was measured according to JIS-K6911. As a result, the dielectric constant at 1 MHz was 2.91, and the transmittance at 400 nm was 90%.
[0036]
(Example 2) The polyimide solution obtained in Synthesis Example 2 was applied to an aluminum plate having a thickness of 100 µm by spin coating and baked at 250 ° C to form a 10 µm polyimide film. Thereafter, the dielectric constant of this aluminum plate was measured according to JIS-K6911. As a result, the dielectric constant at 1 MHz was 2.68, and the transmittance at 400 nm was 88%.
[0037]
(Comparative Example 1) The polyimide solution obtained in Synthesis Example 3 was applied to an aluminum plate having a thickness of 100 μm by spin coating and baked at 250 ° C. to form a 10 μm polyimide film. Thereafter, the dielectric constant of this aluminum plate was measured according to JIS-K6911. As a result, the dielectric constant at 1 MHz was 3.40, and the transmittance at 400 nm was 36%.
[0038]
(Comparative Example 2) The polyimide solution obtained in Synthesis Example 4 was applied to an aluminum plate having a thickness of 100 μm by spin coating and baked at 250 ° C. to form a 10 μm polyimide film. Thereafter, the dielectric constant of this aluminum plate was measured according to JIS-K6911. As a result, the dielectric constant at 1 MHz was 3.10, and the transmittance at 400 nm was 95%.
[0039]
Comparative Example 3 The polyimide solution obtained in Synthesis Example 5 was applied to an aluminum plate having a thickness of 100 μm by spin coating and baked at 250 ° C. to form a 10 μm polyimide film. Thereafter, the dielectric constant of this aluminum plate was measured according to JIS-K6911. As a result, the dielectric constant at 1 MHz was 3.4, and the transmittance at 400 nm was 26.6%.
[0040]
In Examples 1 and 2, the dielectric constant at 1 MHz was low, and the transmittance at 400 nm was high.
[0041]
In Comparative Example 1, since no fluorine was introduced into the acid anhydride, the dielectric constant at 1 MHz was high. Further, the fired film was colored deeply, and the transmittance at 400 nm was low.
In Comparative Example 2, since the firing temperature was too low, the dielectric constant at 1 MHz was high.
In Comparative Example 3, the dielectric constant was high because fluorine was not introduced in both the acid anhydride and diamine. Further, the fired film was colored deeply, and the transmittance at 400 nm was low.
[0042]
【The invention's effect】
The polyimide resin composition of the present invention is an insulating agent for active matrix liquid crystal display elements that has excellent insulation at a low baking temperature of 250 ° C. or less and has high transmittance.

Claims (1)

An insulating material for an active matrix liquid crystal display element comprising, as a resin component, a polyimide having a repeating unit represented by the general formula (1) in which X and / or Y in the formula is an organic group having at least one fluorine , X is the formula (2), An insulating material for an active matrix liquid crystal display element, wherein Y is a formula (12), (13), and / or (14).
(In the formula, X represents a tetravalent organic group, and Y represents a divalent organic group.)