JPH0812757A - Polyimide having mesogenic group - Google Patents

Abstract

PURPOSE:To obtain a new polyimide which can be produced by firing at low temperatures for a short time and is useful for a liquid crystal aligning film excellent in the ability to align liquid crystals without causing the fading deterioration of a color filter, etc., in producing a liquid crystal cell. CONSTITUTION:This polyimide comprises structural units represented by formulae I and II, wherein, m is an integer of 2-20; n is 1 or 2; r is 1-20 C alkyl or alkoxy; and A is phenyl or 3,3',4,4'-biphenyl.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyimide having a mesogen group, a liquid crystal alignment film using the same, and a liquid crystal display device.

[0002]

2. Description of the Related Art Polyimide resin is an excellent plastic that has the highest heat resistance among commercially available plastics, has little change in characteristics with temperature, and has good impact resistance, dimensional stability, electrical characteristics, and abrasion resistance. . Utilizing these characteristics, it is used as a material for aerospace and machinery, including electrical and electronic fields such as insulation and sealing materials and printed circuit boards. In addition, in a liquid crystal display element, generally, a liquid crystal alignment film using a polyimide polymer film is formed on the surface of a transparent electrode on the inner surface of a transparent substrate which is arranged to face each other with a predetermined gap. In recent years, a polyimide resin has attracted attention as a material for a liquid crystal alignment film of the liquid crystal display element, and many polyimide-based alignment films have been developed.

In a liquid crystal display element used in a timepiece or a calculator, a pair of upper and lower sheets are paired with each other. The nematic liquid crystal molecules are aligned 90 degrees between the substrates on which the liquid crystal alignment film using the polyimide polymer film is formed.
The twisted nematic (hereinafter abbreviated as TN) mode with a twisted structure is mainly adopted. A super twisted nematic (hereinafter abbreviated as STN) mode in which a liquid crystal has a twist angle of 180 to 270 degrees is also commonly used at present, and is mass-produced for large displays such as word processors and personal computers. The liquid crystal alignment film used in such a liquid crystal display device is not sufficient to simply align the liquid crystal molecules, and the liquid crystal alignment film is formed in order to improve the response and ensure the bistability. Between the substrate surface and liquid crystal molecules, 1 to 4 degrees in TN mode, 4 to 8 in STN mode
It must have a pretilt angle of degrees. Further, although it is desired to color the liquid crystal display element, there is a color filter method as one of the color display methods that are currently widely used. This is a system in which a color filter is provided on a transparent electrode of a liquid crystal cell, and its application to a liquid crystal color television or a display for a personal computer is actively carried out. But,
Since the dye type color filter has relatively low heat resistance, the filter may be discolored by firing. Therefore,
When a dye-type color filter is attached, it is desirable to fire at a temperature as low as possible when manufacturing a liquid crystal cell.

Japanese Unexamined Patent Publication Nos. 3-179322 and 3
JP-A-179323 and JP-A-5-27244 disclose a polyimide and a liquid crystal alignment film using a diamine having a mesogenic group in a side chain as a monomer. However, these polyimides need to be baked at a temperature of 200 to 250 ° C. for 1 to 2 hours to form a polyimide when forming the polyimide, and when a dye color filter having low heat resistance is attached to the substrate, There was a risk of fading deterioration of the filter.

[0005]

[Problems to be Solved by the Invention] From the above problems,
An object of the present invention is to produce a polyimide film at a low temperature (200
An electric and electronic material which can be produced by firing for a short time (30 minutes or less), particularly a liquid crystal cell without causing deterioration of discoloration of a color filter or the like,
A novel polyimide useful as a liquid crystal alignment film capable of having a pretilt angle of about 1 to 8 degrees.

[0006]

SUMMARY OF THE INVENTION The inventors of the present invention have developed a high polyimide film which has excellent adhesion to a substrate, a pretilt angle of 1 to 8 degrees, can be manufactured by firing at low temperature for a short time, and is excellent in heat resistance. We have made extensive studies on the molecular film. As a result, the side chain has a spacer made of a flexible alkyl chain,
A diamine component having a mesogenic group such as a phenylcyclohexyl group or a phenylbicyclohexyl group at its tip and a polyamic acid obtained by using 2,2-bis (4-aminophenoxyphenyl) -propane as a monomer are obtained by firing Since the polyimide having the structural units of Chemical formulas 1 and 2 can be manufactured by firing at a relatively low temperature for a short time, it does not cause deterioration of discoloration of a color filter or the like at the time of manufacturing a liquid crystal cell, and further has a film forming property and a substrate property. The inventors have found that they have excellent adhesion and thermal stability and have a pretilt angle of 1 to 8 degrees, and completed the present invention.

That is, the present invention has the following configuration. (1) A polyimide comprising a structural unit represented by Chemical formula 9 and a structural unit represented by Chemical formula 10.

[Chemical 9] (However, m = 2-20 integer, n = 1-2, R has 1 carbon atom
To 20 alkyl groups or alkoxy groups, and A represents a phenyl group or a 3,3 ′, 4,4′-biphenyl group. )

[Chemical 10] (However, A represents a phenyl group or a 3,3 ′, 4,4′-biphenyl group.) (2) A polyimide comprising the structural unit represented by Chemical formula 11.

[Chemical 11] (However, m = 2-20 integer, n = 1-2, R has 1 carbon atom
To 20 alkyl groups or alkoxy groups, and A represents a phenyl group or a 3,3 ′, 4,4′-biphenyl group. (3) By reacting the diamino compounds represented by Chemical formulas 12 and 13 with a tetracarboxylic dianhydride represented by Chemical formula 14 in a solvent to produce a polyamic acid, and heating the polyamic acid. The resulting polyimide.

[Chemical 12] (However, m = 2-20 integer, n = 1-2, R has 1 carbon atom
To 20 alkyl groups or alkoxy groups. )

[Chemical 13]

Embedded image (However, A is a phenyl group or 3,3 ', 4,4'-
Indicates a biphenyl group. (4) A polyimide obtained by reacting a diamino compound represented by Chemical formula 15 with a tetracarboxylic dianhydride represented by Chemical formula 16 in a solvent to produce a polyamic acid, and heating the polyamic acid. .

[Chemical 15] (However, m = 2-20 integer, n = 1-2, R has 1 carbon atom
To 20 alkyl groups or alkoxy groups. )

Embedded image (However, A is a phenyl group or 3,3 ', 4,4'-
Indicates a biphenyl group. (5) A liquid crystal alignment film comprising the polyimide described in any one of the above items (1) to (4). (4) A liquid crystal display device comprising the liquid crystal alignment film according to the item (5).

In the polyimide of the present invention, a polyimide precursor polyamic acid obtained by a condensation reaction of a diamine and a tetracarboxylic dianhydride is coated on a substrate and heat-treated for dehydration reaction to form a polyimide film on the substrate. It is manufactured by forming. That is, in the present invention, as the diamine, 3,5-diaminobenzoic acid [4- (4-alkyl-transcyclohexyl) phenoxyalkyl] ester represented by Chemical Formula 15 is converted into a compound represented by Chemical Formula 15 alone or A mixture of 2,2-bis (4-aminophenoxyphenyl) -propane represented by 13 is used.

The 3,5-diaminobenzoic acid [4- (4-propyl-transcyclohexyl) phenoxyalkyl] ester represented by the above Chemical formula 15 can be produced according to the reaction formula of the following Chemical formula 17.

[Chemical 17] (However, m = 1 to integer 20, n = 1 to 2, R is 1 carbon atom
To 20 alkyl groups or alkoxy groups, and X represents halogen. )

That is, first, 4- (4-propyl-transcyclohexyl) phenol and α, ω-alkylenehalohydrin were added in the presence of excess potassium carbonate.
Dimethylacetamide (DMAc), N-methyl-2-
The alcohol compound is obtained by condensation in a solvent such as pyrrolidone (NMP) or dimethylformamide (DMF) at a temperature of 100 to 150 ° C. At this time, the number of moles of α, ω-alkylenehalohydrin is preferably equal to or more than the number of moles of 4- (4-propyl-transcyclohexyl) phenol. Subsequently, this compound was treated with tetrahydrofuran (TH) in the presence of a tertiary organic base such as triethylamine and pyridine.
F), in a solvent such as toluene or dioxane, -1
It is condensed with 3,5-dinitrobenzoyl chloride at a temperature of 0 to 20 ° C. to give 3,5-dinitrobenzoic acid [4-
(4-Propyl-transcyclohexyl) phenoxyalkyl] ester is obtained. At this time, it is desirable that the chloride is 0.9 to 1.1 mol and the amine is 1.0 mol or more per 1 mol of the compound. Finally, this compound is catalytically reduced in the presence of a palladium-carbon catalyst in an amount of about 1/10 to 1/2 weight of the compound in a solvent such as ethyl acetate, toluene, THF, or an alcohol system to give 3,5-diaminobenzoic acid. [4- (4-propyl-transcyclohexyl)
Phenoxyalkyl] ester is obtained.

The tetracarboxylic dianhydride used in the present invention is a compound represented by Chemical formula 16, for example, pyromellitic dianhydride (PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride. Anhydrous (BPDA) is used.

The condensation reaction between the above diamine and the tetracarboxylic dianhydride is carried out under anhydrous conditions such as dimethylacetamide (DMAc) and N-methyl-2-pyrrolidone (NM).
P), dimethylformamide (DMF), dimethylsulfoxide (DMSO), sulfolane, butyrolactone,
-10 to 30 in a solvent such as cresol, phenol, halogenated phenol, cyclohexanone, dioxane, or tetrahydrofuran, preferably in NMP solvent.
It is carried out at a temperature of ° C to obtain a polyamic acid.

In order to form the polyimide film or the liquid crystal alignment film of the present invention on the substrate, the polyamic acid obtained by the above method is added to NMP, DMAc, DMF, DMS.
Dissolve in a solvent such as O, butyl cellosolve, or ethyl carbitol, and adjust to a 0.1 to 30 wt% solution,
This solution is applied onto a substrate by a brush coating method, a dipping method, a spin coating method, a spray method, a printing method, etc., and then the coated substrate is subjected to a heat treatment at 200 ° C. or lower for 30 minutes or less, and a dehydration ring-closing reaction. Then, a polyimide-based polymer film is formed. The heat treatment conditions at this time are preferably 180 to 200 ° C. and 3
Although it is 0 minutes, it can be performed at 100 to 450 ° C. for 30 minutes to 2 hours.

Before applying the polyamic acid solution on the substrate, the surface of the substrate is surface-treated with a silane coupling agent,
Forming a polyimide polymer film on it improves the adhesion between the film and the substrate. Then, the formed polyimide film surface is rubbed in one direction with a cloth or the like to obtain a liquid crystal alignment film. The liquid crystal aligning film of the present invention has a good liquid crystal aligning property of 1 to 8
Can have a pretilt angle of degrees.

The molar ratio of the structural units represented by Chemical formulas 11 and 10 in the polyimide molecule is as follows.
Is preferably 90 to 90 mol%, Compound 10 is preferably 95 to 10 mol%,
More preferably, the chemical formula 11 is 30 to 70 mol%,
Is 70 to 30 mol%. By using a polyimide having a molar ratio of each structural unit, a polyimide having excellent film-forming properties and adhesion to a substrate can be obtained.

A glass substrate is usually used as a substrate used as a liquid crystal display element, and an electrode, specifically, a transparent electrode of ITO (indium oxide-tin oxide) or tin oxide is formed. An insulating film for preventing alkali elution from the substrate, an undercoat film such as a color filter or color filter overcoat may be provided between the substrate and the electrode, and an overcoat such as an insulating film or a color filter film may be provided. A membrane may be provided. Also,
Active elements such as thin film transistor elements and metal insulator metal elements may be formed on the electrodes.
These electrodes, undercoat, and other internal structure of the liquid crystal cell can be used in the same structure as the conventional liquid crystal display element.

A cell is formed using the substrate thus formed, liquid crystal is injected, and the injection port is sealed to produce a liquid crystal display element. As the liquid crystal to be enclosed, various liquid crystals such as a normal nematic liquid crystal and a liquid crystal added with a dichroic dye can be used.

The liquid crystal display device of the present invention is characterized in that it has a liquid crystal alignment film having a good liquid crystal alignment property and a pretilt angle of 1 to 8 degrees, that is, the liquid crystal alignment film of the present invention. Yes, it is usually composed of a substrate, a voltage applying means, a liquid crystal alignment film, a liquid crystal layer and the like.

[0019]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

The physical properties of the polyimide or polyamic acid obtained in the examples were measured by the following methods. Decomposition temperature (Td): A differential thermogravimetric simultaneous measurement device (TG / DTA-220 manufactured by Seiko Denshi Kogyo Co., Ltd.) was used to measure the temperature at a temperature rising rate of 10 ° C./min. Logarithmic viscosity: 3 in MNP solvent using Ubbelohde viscometer
It was measured at a concentration of 0.5 g / dl at 0 ° C. Pretilt angle: Measured using the crystal rotation method.

[0021]

【Example】

Example 1 Production of Polyimide Comprising Structural Units of Chemical Formulas 11 and 10: 1) 3,5-Diaminobenzoic Acid [4-
(4-Propyl-transcyclohexyl) phenoxyhexyl] ester (provided that m = 6, n = 1, R = C
₃ H ₇ ) production. In a 1 L three-necked flask equipped with a condenser and a stirrer, 500 ml of dimethylformamide and 21.8 g (0.10 g) of 4- (4-propyl-transcyclohexyl) phenol.
mol) and 41.4 g (0.3 mol) of potassium carbonate were added and stirred at room temperature. 16.4 g (0.12 mol) of 6-chloro-1-hexanol was added thereto, and the mixture was vigorously stirred at 100 ° C. After reacting for 10 hours, this solution was added to 2 L of water and extracted with 1.5 L of ethyl acetate. Then 3 organic layers
It was washed 3 times with N hydrochloric acid, 3 times with 2N aqueous sodium hydroxide solution, and further washed with water. The obtained ethyl acetate layer was dried over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure, and the obtained crystal was recrystallized twice with n-heptane to give 4- (4-propyl-transcyclohexyl) phenoxyhexanol 2
2.6 g (0.071 mol) was obtained. Melting point (C-S point)
Was 59.4 to 60.5 ° C.

Then, 200 ml of tetrahydrofuran (THF) was added to a 500 ml three-necked flask equipped with a stirrer.
And 4- (4-propyl-transcyclohexyl) phenoxyhexanol (12.1 g, 0.038)
mol) and 6.4 ml of triethylamine were added, and the mixture was stirred at 0 ° C. A solution prepared by dissolving 9.64 g (0.042 mol) of 3,5-dinitrobenzoyl chloride in 50 ml of THF was added dropwise thereto over 30 minutes, and the reaction was carried out for 6 hours as it was. After completion of the reaction, this liquid was added to 1 L of water and extracted with 1.5 L of ethyl acetate. Then, the organic layer was washed with 3N hydrochloric acid three times,
The extract was washed 3 times with saturated aqueous sodium hydrogen carbonate and further with water. The obtained ethyl acetate layer was dried over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure, and the obtained crystal was recrystallized twice with ethyl acetate to give 3,5-dinitrobenzoic acid [4- (4- Propyl-transcyclohexyl) phenoxyhexyl] ester 1
4.8 g (0.029 mol) was obtained. Melting point is 85.6 ~
It was 87.0 ° C. The structure of this compound is IR and NMR
After confirming in step 1, the compound was catalytically reduced.

That is, 3,5-dinitrobenzoic acid [4
1-4.0 g (0.027 mol) of-(4-propyl-transcyclohexyl) phenoxyhexyl] ester was dissolved in 300 ml of ethyl acetate, 2 g of 5 wt% palladium-carbon was added, and catalytic reduction was carried out under normal temperature and normal pressure. After completion of the reaction, the catalyst was filtered off, the solvent was distilled off under reduced pressure, and the obtained crystals were recrystallized twice with n-heptane / ethyl acetate to give 3,5-
11.3 g of diaminobenzoic acid [4- (4-propyl-transcyclohexyl) phenoxyhexyl] ester
(0.025 mol) was obtained. The melting point of this compound is 99.
It was 2-101.8 degreeC.

2) Polymerization Reaction In a 100 ml three-necked flask, 3,5-diaminobenzoic acid [4- (4-propyl-transcyclohexyl) phenoxyhexyl] ester 0.4706 g (1.05 m) was added.
mol), 2,2-bis (4-aminophenoxyphenyl) -propane 0.1847 g (0.45 mmol), N
-Methyl-2-pyrrolidone (hereinafter abbreviated as NMP) (3 ml) was added, and the mixture was stirred and dissolved at room temperature under a nitrogen stream. Next, this liquid was kept at 10 ° C. and 0.4413 g (1.50 mmo) of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride.
l) was added. The vessel wall was rinsed with 3 ml of NMP, and the reaction was continued for 3 hours. The obtained reaction liquid was N-methyl-
2-pyrrolidone / butyl cellosolve = 1/1 solvent 4.
After diluting to 3 wt%, it was applied on an ITO glass substrate by a spin coating method (spinner method). 30 minutes at 200 ℃ after coating
It was baked for minutes to obtain a substrate on which a polyimide film having a film thickness of 600 angstrom was formed. This polyimide had a decomposition temperature of 373.5 ° C. The remaining reaction solution was poured into 300 ml of methanol, and the deposited precipitate was filtered. This filtered material was dried under reduced pressure at room temperature to obtain a polyamic acid.
The intrinsic viscosity of this polyamic acid is 0.66 (30 ° C, 0.
5 g / dl, NMP solution).

3) Cell preparation and pretilt angle measurement The film surfaces of the two polyimide film-formed substrates were each rubbed, and a liquid crystal cell having a cell thickness of 20 μm was assembled so that the rubbing directions were anti-parallel. Liquid crystal ZLI-1132 manufactured by K.K. Then, the liquid crystal was heat-treated at 120 ° C. for 30 minutes. After the heat treatment, the pretilt angle was calculated to be 2.7 degrees.

Examples 2-3 3,5-diaminobenzoic acid [4- (4-propyl-transcyclohexyl) phenoxyhexyl] ester,
And 2,2-bis (4-aminophenoxyphenyl)-
Example 2) was followed except that the propane component ratio was changed. Table 1 shows the component ratios and the physical properties of the obtained polyimide. The infrared absorption spectrum of the polyimide film obtained in Example 3 is shown in FIG.

Example 4 Except that the tetracarboxylic dianhydride was changed to pyromellitic dianhydride (0.3272 g, 1.50 mmol).
According to 2) of Example 1. Table 1 shows the physical properties of the obtained polyimide. A cell was assembled in the same manner as in 3) of Example 1, and the pretilt angle was measured and found to be 7.7 degrees.

Example 5 Preparation of Polyesterimide Consisting of Structural Units Shown Only in Chemical Formula 11, 3,5-diaminobenzoic acid [4- (4-propyl-transcyclohexyl) phenoxyhexyl] ester 0 in a 100 ml three-necked flask. .6723
g (1.50 mmol) and 3 ml of N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP) were added, and the mixture was stirred and dissolved at room temperature under a nitrogen stream. Then keep this solution at 10 ° C,
0.4413 g (1.50 mmol) of 3 ', 4,4'-biphenyltetracarboxylic dianhydride was added. NMP
The vessel wall was rinsed with 3 ml, and the reaction was continued for 3 hours.
The obtained reaction solution was diluted to 4.0 wt% with N-methyl-2-pyrrolidone / butyl cellosolve = 1/1 solvent, and then IT
It was applied on an O glass substrate by a spin coating method (spinner method). After coating, it was baked at 200 ° C. for 30 minutes to obtain a polyimide film. This polyimide had a decomposition temperature of 377.1 ° C. The remaining reaction solution was poured into 300 ml of methanol, and the deposited precipitate was filtered. This filtered material was dried under reduced pressure at room temperature to obtain a polyamic acid. The intrinsic viscosity of this polyamic acid is 0.44 (30 ° C, 0.5 g / dl, NM
P solution). The infrared absorption spectrum of the obtained polyimide film is shown in FIG.

Example 6 1) 3,5-diaminobenzoic acid [4-
(4-Ethyl-transcyclohexyl) phenoxypropyl] ester (provided that m = 3, n = 1, R = C ₂ H ₅ ).
Manufacturing of. 4- (4-Ethyl-transcyclohexyl) phenol was used instead of 4- (4-propyl-transcyclohexyl) phenol, and 3-bromo-1-propanol was used instead of 6-chloro-1-hexanol. It was manufactured according to 1) of Example 1. The melting point of this compound was 91.5 to 92.4 ° C.

2) Polymerization reaction 3,5-diaminobenzoic acid [4-
(4-ethyl-transcyclohexyl) phenoxypropyl] ester 0.2971 g (0.75 mmol),
2,2-bis (4-aminophenoxyphenyl) -propane, except that 0.3079 g (0.75 mmol) is used,
According to 2) of Example 1. Table 1 shows the physical properties of the obtained polyimide.

Example 7 1) 3,5-diaminobenzoic acid [4-
(Trans, trans-4'-propyl-4,4'-bicyclohexyl) Preparation of phenoxy hexyl] ester (provided that m = 6, n = 2, R = C 3 H 7). According to 1) of Example 1 except that 4- (trans, trans-4′-propyl-4,4′-bicyclohexyl) phenol was used instead of 4- (4-propyl-transcyclohexyl) phenol. Manufactured. The melting point (C-S point) of this compound was 162.3 to 163.8 ° C.

2) Polymerization reaction As a diamine component, 3,5-diaminobenzoic acid [4-
(Trans, trans-4'-propyl-4,4'-bicyclohexyl) phenoxyhexyl] ester 0.4
006 g (0.75 mmol), 2,2-bis (4-aminophenoxyphenyl) -propane 0.3079 g (0.7
5 mmol) was used, and the procedure was performed according to 2) of Example 1. Table 1 shows the physical properties of the obtained polyimide.

[0033]

[Table 1]

[0034]

The polyimide obtained according to the present invention can be produced by baking at low temperature for a short time and has a decomposition temperature of 350.
It is as high as ~ 400 ° C and can be used at high temperatures. Also,
The liquid crystal alignment film using this polyimide is excellent in the adhesion to the substrate and the liquid crystal alignment property, and has a pretilt angle of about 1 to 8 degrees, so it is used for the alignment film of ordinary liquid crystal cells (for TN and STN). It is useful as a material.

[Brief description of drawings]

1] IR of the polyimide film obtained in Example 3
It is a spectrum figure.

FIG. 2 IR of polyimide film obtained in Example 5
It is a spectrum figure.

Claims (6)

[Claims] 1. A polyimide comprising a structural unit represented by Chemical formula 1 and a structural unit represented by Chemical formula 2. Embedded image (However, m = 2-20 integer, n = 1-2, R has 1 carbon atom
To 20 alkyl groups or alkoxy groups, and A represents a phenyl group or a 3,3 ′, 4,4′-biphenyl group. ) (However, A represents a phenyl group or a 3,3 ′, 4,4′-biphenyl group.) 2. A polyimide comprising a structural unit represented by Chemical formula 3. Embedded image (However, m = 2-20 integer, n = 1-2, R has 1 carbon atom
To 20 alkyl groups or alkoxy groups, and A represents a phenyl group or a 3,3 ′, 4,4′-biphenyl group. ) 3. A diamino compound represented by Chemical formula 4 or 5 and a tetracarboxylic dianhydride represented by Chemical formula 6 are reacted in a solvent to produce a polyamic acid, and the polyamic acid is heated. The polyimide obtained by. [Chemical 4] (However, m = 2-20 integer, n = 1-2, R has 1 carbon atom
To 20 alkyl groups or alkoxy groups. ) [Chemical 5] [Chemical 6] (However, A is a phenyl group or 3,3 ', 4,4'-
Indicates a biphenyl group. ) 4. A diamino compound represented by Chemical formula 7 is reacted with a tetracarboxylic dianhydride represented by Chemical formula 8 in a solvent to produce a polyamic acid, which is obtained by heating the polyamic acid. Polyimide. [Chemical 7] (However, m = 2-20 integer, n = 1-2, R has 1 carbon atom
To 20 alkyl groups or alkoxy groups. ) [Chemical 8] (However, A is a phenyl group or 3,3 ', 4,4'-
Indicates a biphenyl group. ) 5. A liquid crystal alignment film comprising the polyimide according to any one of claims 1 to 4. 6. A liquid crystal display device comprising the liquid crystal alignment film according to claim 5.