JPH1184391A - Liquid crystal orientation treating agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyimide material which can be easily imidized and which has lower dependence of a voltage holding rate on the imidization rate by incorporating one kind selected from polymers produced by the reaction of a specified tetracarboxylic acid dianhydride and its deriv. and a specified diamine compd. SOLUTION: This treating agent contains at least one kind selected from polyamic acids described below or polymers with a % imidization rate of the polyamic acids, wherein a satisfies 0<a<=100. The polyamic acids are produced by the reaction of a tetracarboxylic acid dianhydride and its deriv. containing at least 1 mol.% of tetracarboxylic acid dianhydride expressed by formula I (3,5,6-tricarboxy-2-carboxynorbornane-2:3, 5:6-dianhydride) and a diamine compd. expressed by formula II. In the formula II, R is a bivalent org. group. After the agent is applied on a substrate having a transparent electrode, then dried and calcined to form a polyimide film. The surface of the film is subjected to orientation treatment such as rubbing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel liquid crystal aligning agent for a liquid crystal display device. More specifically, the present invention relates to a liquid crystal alignment treatment agent having excellent voltage holding ratio of a liquid crystal cell and excellent liquid crystal alignment.

[0002]

2. Description of the Related Art A liquid crystal display device is a display device utilizing electro-optical change of liquid crystal, and has been remarkably developed as a display device for various displays because of its characteristics such as small size, light weight and low power consumption. Above all, using nematic liquid crystal having positive dielectric anisotropy, the liquid crystal molecules of a pair of opposing electrode substrates are arranged parallel to the substrate, and both substrates are oriented so that the orientation directions of the liquid crystal molecules are perpendicular to each other. A twisted nematic (TN type) field-effect type liquid crystal display element, which is a combination of the above, is a typical example thereof. Further, a super twisted nematic type (STN type) in which both substrates are twisted by 180 to 270 degrees has been developed, and a liquid crystal display element having good display quality even on a large screen can be obtained. In recent years, active matrix driving methods using thin film transistors have been actively developed due to their excellent display characteristics.
The FT (Thin Film Transister) driving method is the most typical one, and its display characteristics have been further improved.

[0003] Accordingly, requirements for a liquid crystal alignment film are becoming more and more severe. Generally, it is necessary to increase the voltage holding ratio in the TFT driving method, and in recent years, it has been desired to obtain a higher voltage holding ratio even at a high temperature such as 60 ° C. to 90 ° C. from the viewpoint of reliability. Therefore, a liquid crystal alignment treatment agent for obtaining a liquid crystal alignment film having a higher voltage holding ratio than before has been required.

Conventionally, polyimide or polyamic acid has been widely used as a liquid crystal alignment film. A typical example is a polyimide using cyclobutanetetracarboxylic dianhydride (JP-A-61-47932).
JP, JP-A-2-287324, polyimides using 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalenesuccinic anhydride, and polyimides characterized by the diamine component used (JP-A-5-436
No. 88) and polyimides using 2,3,5-tricarboxycyclopentylacetic acid or its dianhydride (JP-A-61-205924, JP-A-64-25)
No. 126) and the like.

[0005] Further, since polyamic acid is imidized by being applied on a substrate and then baked, in general, a high voltage holding ratio is often not exhibited unless baked at a high temperature of 200 ° C or higher. In particular, voltage holding ratio at high temperature, for example, 60 ° C. to 90
It is not easy to obtain a device with a sufficiently high voltage holding ratio at high temperatures such as ℃, and there is a problem that the voltage holding ratio is easily changed by firing conditions. In actual production of a liquid crystal device, the firing conditions are strictly controlled. There was a need.

On the other hand, a liquid crystal alignment treatment agent using a solvent-soluble polyimide is obtained by dissolving a polyimide which has already been sufficiently imidized in a solvent, and exhibits a relatively high voltage holding ratio even at a low firing temperature. It is known that the dependence on temperature is small. However, even in this case, it is not always easy to obtain a material having a sufficiently high voltage holding ratio at a high temperature such as 60 ° C. to 90 ° C., and it is necessary to appropriately select a polyimide structure.

In general, the voltage holding ratio is a characteristic that strongly depends on the structure of the polyimide used. In particular, polyimide having an alicyclic structure often shows a higher voltage holding ratio. Gazette, JP
2-287324 and JP-A-61-205924
The alicyclic structure-based polyimide disclosed in Japanese Patent Application Laid-Open Publication No. H10-163, etc. is frequently used. However, these polyimides have problems in that they may not be easily imidized by heating and baking after being applied on a substrate, and that a sufficient voltage holding ratio may not be obtained when the imidation ratio is low. Was.

[0008]

That is, in particular, in the future, TFT
In order to further improve the performance of the liquid crystal display element by the driving method, higher reliability is required than before, showing a higher voltage holding ratio than before, and it is easier to imidize than conventional polyimide, and the voltage holding ratio is higher. There has been a demand for the development of a polyimide material having a smaller dependence on the imidation ratio.

An object of the present invention is to provide a liquid crystal alignment film,
An object of the present invention is to provide a liquid crystal alignment treatment agent comprising a polyimide material which exhibits a higher voltage holding ratio than the conventional one, is easier to imidize than conventional polyimides, and has a smaller dependence of the voltage holding ratio on the imidization ratio.

[0010]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, completed the present invention. That is, the present invention provides the following formula (1)

[0011]

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A tetracarboxylic acid containing at least 1 mol% of a tetracarboxylic dianhydride (3,5,6-tricarboxy-2-carboxynorbornane-2: 3,5: 6-dianhydride) represented by the formula: Acid dianhydride and its derivative and the following formula (2)

[0013]

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(In the formula (2), R represents a divalent organic group.) A polyamic acid produced by reacting with a diamine compound represented by the following formula: The present invention relates to a liquid crystal aligning agent comprising at least one selected from polymers corresponding to the range of ≦ 100.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The liquid crystal alignment treatment agent in the present invention is applied on a substrate with a transparent electrode, then dried and baked to form a polyimide film, and the film surface is subjected to an alignment treatment such as rubbing treatment to form a liquid crystal alignment film. It is used.

In obtaining the liquid crystal aligning agent of the present invention, the content of the tetracarboxylic acid represented by the formula (1) and its derivative in the tetracarboxylic dianhydride and its derivative used is 1 mol%. However, in order to obtain a high voltage holding ratio, it is preferably 30 mol% or more, more preferably 70 mol% or more.
% Or more. The imidation ratio of the polyamic acid varies depending on the solvent used, but in order to obtain a high voltage holding ratio, the imidization ratio is preferably 30% or more, more preferably 50 to 100%.

The method for producing the tetracarboxylic dianhydride represented by the formula (1) used in the present invention is not particularly limited. For example, it is synthesized by the method disclosed in Japanese Patent Publication No. 4-80916. You. Specific examples of the tetracarboxylic dianhydride and its derivative that can be used together with the formula (1) include the following, but the present invention is not particularly limited thereto.

Aromatic tetracarboxylic acids such as pyromellitic acid, benzophenonetetracarboxylic acid, biphenyltetracarboxylic acid and naphthalenetetracarboxylic acid and their dianhydrides and dicarboxylic acid diacid halides, cyclobutanetetracarboxylic acid, cyclobutane Alicyclic tetracarboxylic acids such as pentanetetracarboxylic acid and cyclohexanetetracarboxylic acid and dianhydrides thereof, dicarboxylic acid diacid halides thereof, and aliphatic tetracarboxylic acids such as butanetetracarboxylic acid and dianhydrides thereof And dicarboxylic acid diacid halides.

These tetracarboxylic acids and derivatives thereof are not always used, and one kind or a mixture of two or more kinds may be used. Further, specific examples of the diamine in (2) include the following, but the present invention is not particularly limited thereto. p-phenylenediamine 1,4-bis (4-aminophenyl) benzene 4,4′-diaminobiphenyl 3,3′-dimethyl-4,4′-diaminobiphenyl 3,3′-dimethoxy-4,4′-diamino Biphenyl 3,3'-dihydroxy-4,4'-diaminobiphenyl 3,3'-dichloro-4,4'-diaminobiphenyl 3,3'-dicarboxy-4,4'-diaminobiphenyl 4,4'-bis (4-aminophenoxy) biphenyl diaminodiphenylmethane, diaminodiphenylether, 2,2-diaminodiphenylpropane, 4,4′diaminodiphenylsulfone, diaminobenzophenone, 1,3-bis (4-aminophenoxy) benzene,
1,4-bis (4-aminophenoxy) benzene, 4,
4'-di (4-aminophenoxy) diphenylsulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane 1,1,1,3,3,3-hexafluoro-2,2-bis Aromatic diamines such as [4- (4-aminophenoxy) phenyl] propane; alicyclic diamines such as diaminodicyclohexylmethane, diaminodicyclohexyl ether and diaminocyclohexane; 1,2-diaminoethane; 1,3-diaminopropane And aliphatic diamines such as 1,4-diaminobutane and 1,6-diaminohexane. Furthermore,

[0020]

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(L is an integer of 1 to 10). In order to increase the tilt angle of the liquid crystal, 4,4′-diamino-3-dodecyldiphenyl ether 1-dodecanoxy-2,4-diaminobenzene, 1,1,
-Bis (4-aminophenyl) cyclohexane A diamine having a long-chain alkyl group represented by 2,2-bis [4- (4-aminophenoxy) phenyl] octane or the like can be used.

Further, one or more of these diamines can be used in combination. The tetracarboxylic dianhydride and the diamine are reacted and polymerized to form a polyamic acid. In this case, a tetracarboxylic dianhydride is generally used as the tetracarboxylic acid derivative used.
The molar ratio of tetracarboxylic dianhydride to diamine is preferably 0.8 to 1.2. As in the ordinary polycondensation reaction, the degree of polymerization of the produced polymer increases as the molar ratio approaches 1.

If the degree of polymerization is too low, the strength of the polyimide coating film is insufficient, and if the degree of polymerization is too high, the workability during the formation of the polyimide coating film may deteriorate. Therefore,
The degree of polymerization of the product in this reaction is 0.05 to 5.0 dl / g (at a temperature of 30) in terms of reduced viscosity of the polyamic acid solution.
The concentration is preferably 0.5 g / dl in N-methylpyrrolidone at ° C.

The method of reacting and polymerizing the tetracarboxylic dianhydride with the diamine is not particularly limited,
Generally, a polyamic acid is synthesized by reacting a tetracarboxylic dianhydride with a diamine in an organic polar solvent such as N-methylpyrrolidone. The reaction temperature at that time is from -20 ° C to 1
Any temperature of 50 ° C, preferably -5 ° C to 100 ° C, can be selected.

Further, as a polymerization method of the polyamic acid, an ordinary solution method is preferable. Specific examples of the solvent used in the solution polymerization method include N, N-dimethylformamide,
Examples thereof include N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylphosphoramide, butyllactone, and the like. These may be used alone or as a mixture. Further, even if the solvent does not dissolve the polyamic acid, the solvent may be used by adding the solvent to the above-mentioned solvent as long as a homogeneous solution can be obtained.

The liquid crystal alignment treating agent of the present invention may contain a polyamic acid solution as it is, but contains an organic solvent-soluble polyimide resin adjusted to an arbitrary imidation ratio, that is, contains a polyamic acid and a soluble polyimide, or You may use as a liquid-crystal aligning agent only of soluble polyimide.
The method for obtaining the organic solvent-soluble polyimide resin is not particularly limited, but generally it can be obtained by dehydrating a ring-closing imidized polyamic acid.

The polyamic acid obtained by reacting the tetracarboxylic dianhydride with the diamine can be directly imidized in the solution to obtain a solvent-soluble polyimide solution. When polyamic acid is converted to polyimide in a solution, a method of dehydrating and cyclizing by heating is usually employed. The ring closure temperature by this heat dehydration is 100 ° C to 35 ° C.
Any temperature of 0 ° C., preferably 100 ° C. to 250 ° C., can be selected. The imidation ratio can be controlled to an arbitrary value by selecting the temperature or time during the dehydration ring closure.

As another method for converting a polyamic acid into a polyimide, the ring can be chemically closed using a known dehydration ring-closing catalyst. The imidation ratio can be controlled to an arbitrary value by selecting the temperature or time during the dehydration ring closure. The polyimide solution thus obtained can be used as it is, and methanol,
Polyimide can be used as a powder by precipitating and isolating in a poor solvent such as ethanol, or the polyimide powder can be redissolved in an appropriate solvent before use.

The solvent to be redissolved is not particularly limited as long as it can dissolve the obtained polyimide resin, and examples thereof include 2-pyrrolidone, N-methylpyrrolidone,
N-ethylpyrrolidone, N-vinylpyrrolidone, N, N
-Dimethylacetamide, N, N-dimethylformamide, γ-butyrolactone and the like. The above-described polyamic acid and solvent-soluble polyimide can be used as they are, but may be used as a mixture with one or more polyamic acids or solvent-soluble polyimides. The mixing ratio can be arbitrarily selected.

The solvent used for the liquid crystal aligning agent of the present invention is not particularly limited as long as it can dissolve the polyimide resin. Examples thereof include 2-pyrrolidone, N-methylpyrrolidone, N-ethylpyrrolidone, and N-ethylpyrrolidone. -Vinylpyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, γ-butyrolactone and the like.

Further, even a solvent which does not dissolve the polymer by itself can be used in addition to the above solvents as long as the solubility is not impaired. Examples include ethyl cellosolve, butyl cellosolve, ethyl carbitol-
Butyl carbitol, ethyl carbitol acetate
And ethylene glycol.

Further, propylene glycol derivatives (Japanese Patent Application Laid-Open No. 7-109438) and lactic acid derivatives (Japanese Patent Application Laid-Open No.
No. 28839) can also be used. In order to further improve the adhesion between the polyimide resin film and the substrate, an additive such as a coupling agent can be added to the obtained resin solution. The liquid crystal alignment treatment agent of the present invention is applied to a transparent substrate such as glass or plastic with a transparent electrode, and is baked to form a polyimide film. It can be used as an alignment film.

The liquid crystal used in the present invention is not particularly limited, but is preferably a nematic liquid crystal used in various modes such as TN, STN, TFT and SBE. Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

[0034]

【Example】

Example 1 3,5,6-tricarboxy-2-carboxynorbornane-2: 3,5: 6-dianhydride (hereinafter abbreviated as NDA)
25.02 g (0.1 mol), 10.81 g (0.1 mol) of p-phenylenediamine (hereinafter abbreviated as p-PD)
1) was reacted in 203 g of NMP at room temperature for 24 hours to prepare a polyamic acid solution.

To 50 g of the polyamic acid solution, 21.4 g of acetic anhydride and 9.9 g of pyridine were added as imidization catalysts and reacted at 80 ° C. for 1 hour to obtain a polyimide resin solution. The reduced viscosity ηsp / c of the obtained resin is 0.4 dl / g.
(0.5% by weight NMP solution, 30 ° C.). This solution was poured into 500 ml of methanol, and the obtained white precipitate was separated by filtration and dried to obtain a white polyimide resin powder. NMR confirmed that this polyimide resin powder was 50% imidized.

4 g of this powder was mixed with 76 g of γ-butyrolactone.
To obtain a solvent-soluble polyimide resin (NDA / p-PD) solution having a solid content of 5%. This solution was spin-coated on a glass substrate with a transparent electrode at 2000 rpm,
The resultant was baked at 50 ° C. for 60 minutes to obtain a polyimide film having a thickness of 1000 °. The imidation ratio of this polyimide film was confirmed to be 90% from the IR spectrum.

After rubbing this coating film,
After spraying a 6μ spacer on the film surface, the rubbing direction was almost perpendicular to the nematic liquid crystal (MLC-20 manufactured by Merck).
03) was injected to form a 90 ° twist liquid crystal cell.
Observation of the alignment state of the liquid crystal cell with a polarizing microscope confirmed that the liquid crystal cell had a uniform alignment without any defect. When the voltage holding ratio of the liquid crystal cell was measured, the values were as high as 98% at 23 ° C. and 88% at 90 ° C. The holding ratio of the liquid crystal cell was ± 5 V for the liquid crystal cell and the pulse width was 64 μm.
s and a frequency of 64 μs.

Example 2 NDA 25.02 g (0.1 mol), diaminodiphenyl ether (hereinafter abbreviated as DDE) 20.02 g (0.
(1 mol) in 255 g of NMP at room temperature for 24 hours to prepare a polyamic acid solution. 50 g of this polyamic acid solution was mixed with 17.0 acetic anhydride as an imidization catalyst.
g of pyridine and 7.9 g of pyridine were added and reacted at 140 ° C. for 1 hour to obtain a polyimide resin solution. The reduced viscosity ηsp / c of the obtained resin is 0.4 dl / g (0.5% by weight NMP solution,
30 ° C). This solution was poured into 500 ml of methanol, and the obtained white precipitate was separated by filtration and dried to obtain a white polyimide resin powder. NMR confirmed that the polyimide resin powder was 94% imidized.

4 g of this powder was mixed with 76 g of γ-butyrolactone.
To obtain a solvent-soluble polyimide resin (NDA / DDE) solution having a solid concentration of 5%. This solution was spin-coated at 2000 rpm on a glass substrate with a transparent electrode,
It was baked for 0/60 minutes to obtain a polyimide film having a thickness of 1000 °. The imidation ratio of this polyimide film was confirmed to be 94% from the IR spectrum.

After rubbing the coating film in the same manner as in Example 1, a 6 μm spacer was sprayed on the film surface, and then the rubbing direction was made almost perpendicular to the liquid crystal (MLC-2 manufactured by Merck).
003) was injected to form a 90 ° twist liquid crystal cell. Observation of the alignment state of the liquid crystal cell with a polarizing microscope confirmed that the liquid crystal cell had a uniform alignment without any defect.

When the voltage holding ratio of the liquid crystal cell was measured, it showed a high value of 97% at 23 ° C. and 84% at 90 ° C.

Comparative Example 1 30.03 g (0.1 mol) of 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalenesuccinic dianhydride (hereinafter abbreviated as TDA), p-PD10. 8
1 g (0.1 mol) was reacted in 231 g of NMP at room temperature for 3 hours to prepare a polyamic acid solution.

To 50 g of the polyamic acid solution, 18.7 g of acetic anhydride and 8.7 g of pyridine were added as imidization catalysts and reacted at 80 ° C. for 1 hour to obtain a polyimide resin solution. The reduced viscosity ηsp / c of the obtained resin is 0.8 dl / g.
(0.5% by weight NMP solution, 30 ° C.). This solution was poured into 500 ml of methanol, and the obtained white precipitate was separated by filtration and dried to obtain a white polyimide resin powder. NMR confirmed that the polyimide resin powder was 90% imidized.

4 g of this powder was mixed with γ-butyrolactone 76
g) to obtain a solvent-soluble polyimide resin (TDA / p-PD) solution having a solid concentration of 5%. This solution was spin-coated on a glass substrate with a transparent electrode at 3000 rpm,
It was baked at 00 ° C. for 60 minutes to obtain a polyimide film having a thickness of 1000 °. The imidation ratio of this polyimide film was confirmed to be 90% from the IR spectrum.

Thereafter, in the same manner as in Example 1, TDA / p-P
A liquid crystal cell of D was prepared. Observation of the alignment state of the liquid crystal cell with a polarizing microscope confirmed that the liquid crystal cell had a uniform alignment without any defect. When the voltage holding ratio of the liquid crystal cell of TDA / p-PD was measured, it was 97% at 23 ° C.
77% at 90 ° C. NDA / p-PD of Example 1
The voltage holding ratio at a high temperature is lower than that of a liquid crystal cell using.

Comparative Example 2 30.03 g (0.1 mol) of TDA, 20.0 DDE
2 g (0.1 mol) was reacted in 231 g of NMP at room temperature for 3 hours to prepare a polyamic acid solution. 50 g of this polyamic acid solution was mixed with acetic anhydride 1 as an imidation catalyst.
5.3 g and pyridine 7.1 g were added and reacted at 80 ° C. for 1 hour to obtain a polyimide resin solution. The reduced viscosity ηsp / c of the obtained resin was 0.8 dl / g (0.5% by weight NMP solution, 30 ° C.). This solution was poured into 500 ml of methanol, and the resulting white precipitate was filtered off, dried,
A white polyimide resin powder was obtained. NMR confirmed that the polyimide resin powder was 100% imidized.

4 g of this powder was γ-butyrolactone 76
g) to obtain a solvent-soluble polyimide resin (TDA / DDE) solution having a solid content of 5%. This solution was spin-coated on a glass substrate with a transparent electrode at 3000 rpm,
The resultant was baked at 0 ° C. for 60 minutes to obtain a polyimide film having a thickness of 1000 °. The imidation ratio of this polyimide film was confirmed to be 100% from the IR spectrum.

Thereafter, TDA / DDE is performed in the same manner as in the first embodiment.
Liquid crystal cell was prepared. Observation of the alignment state of the liquid crystal cell with a polarizing microscope confirmed that the liquid crystal cell had a uniform alignment without any defect. When the voltage holding ratio of the TDA / DDE liquid crystal cell was measured, the voltage holding ratio was 97% at 23 ° C.
It was 71% at ° C. The voltage holding ratio at high temperature is lower than that of the liquid crystal cell using NDA / DDE of Example 2.

Comparative Example 3 19.41 g (0.099 m) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (hereinafter abbreviated as CBDA)
ol), 10.81 g (0.1 mol) of p-PD was added to NM
The reaction was carried out at room temperature for 3 hours in 171 g of P to prepare a polyamic acid solution. The reduced viscosity ηsp / c of the obtained resin is 1.
It was 0 dl / g (0.5% by weight NMP solution, 30 ° C.). This polyamic acid (CBDA / p-PD) solution was diluted with NMP to a solid concentration of 4%, and the solution was spin-coated at 3000 rpm on a glass substrate with a transparent electrode, and baked in a vacuum at 300 ° C. for 60 minutes. And a film thickness of 100
A 0 ° polyimide film was obtained. The imidation ratio of this polyimide film was confirmed to be 90% from the IR spectrum.

Thereafter, CBDA / p-
A PD liquid crystal cell was prepared. Observation of the alignment state of the liquid crystal cell with a polarizing microscope confirmed that the liquid crystal cell had a uniform alignment without any defect. The voltage holding ratio of the CBDA / p-PD liquid crystal cell was measured.
% At 90 ° C. was 53%. The voltage holding ratio at a high temperature was lower than that of a liquid crystal cell using NDA. ND of Example 1
The voltage holding ratio at high temperatures is lower than that of a liquid crystal cell using A / p-PD.

Comparative Example 4 19.41 g (0.099 mol) of CBDA, DDE2
0.02 g (0.1 mol) was reacted in 224 g of NMP at room temperature for 3 hours to prepare a polyamic acid solution. The reduced viscosity ηsp / c of the obtained resin is 1.0 dl / g (0.5
Wt% NMP solution, 30 ° C). This polyamic acid (CBDA / DDE) solution was diluted with NMP so as to have a solid concentration of 4%, and this solution was spin-coated at 3000 rpm on a glass substrate with a transparent electrode.
The resultant was fired in vacuum for 0 minutes to obtain a polyimide film having a thickness of 1000 °. The imidation ratio of this polyimide film was confirmed to be 95% from the IR spectrum.

Thereafter, CBDA / DD was performed in the same manner as in Example 1.
A liquid crystal cell of E was prepared. Observation of the alignment state of the liquid crystal cell with a polarizing microscope confirmed that the liquid crystal cell had a uniform alignment without any defect. When the voltage holding ratio of the CBDA / DDE liquid crystal cell was measured, it was 96% at 23 ° C.
It was 47% at 90 ° C. The voltage holding ratio at high temperature is lower than that of the liquid crystal cell using NDA / DDE of Example 2.

Example 3 The NDA / p-PD resin solution used in Example 1 was spin-coated at 2000 rpm on a glass substrate with a transparent electrode.
The resultant was baked at 90 ° C. for 60 minutes to obtain a polyimide film having a thickness of 1000 °. The imidation ratio of this polyimide film was confirmed to be 50% from the IR spectrum.

A liquid crystal (MLC-2003, manufactured by Merck) was injected in the same manner as in Example 1 to prepare a liquid crystal cell. Observation of the alignment state of the liquid crystal cell with a polarizing microscope confirmed that the liquid crystal cell had a uniform alignment without any defect. When the voltage holding ratio of this liquid crystal cell was measured, it was 97% at 23 ° C. and 77% at 90 ° C., indicating a high value even when the imidization ratio was low.

Comparative Example 5 30.03 g (0.1 mol) of TDA, p-PD10.
81 g (0.1 mol) in 231 g NMP at room temperature
The mixture was reacted for a period of time to prepare a polyamic acid solution. To 50 g of this polyamic acid solution, 18.7 g of acetic anhydride and 8.7 g of pyridine were added as imidation catalysts and reacted at 25 ° C. for 3 hours to obtain a polyimide resin solution. The reduced viscosity ηsp / c of the obtained resin is 0.8 dl / g (0.5 wt% NMP
Solution, 30 ° C.). This solution was poured into 500 ml of methanol, and the obtained white precipitate was separated by filtration and dried to obtain a white polyimide resin powder. NMR confirmed that this polyimide resin powder was 60% imidized.

4 g of this powder was mixed with γ-butyrolactone 76
g) to obtain a solvent-soluble polyimide resin (TDA / p-PD) solution having a solid concentration of 5%. This solution was spin-coated on a glass substrate with a transparent electrode at 3000 rpm,
The resultant was baked at 90 ° C. for 60 minutes to obtain a polyimide film having a thickness of 1000 °. The imidation ratio of this polyimide film was confirmed to be 60% from the IR spectrum.

Thereafter, a liquid crystal cell was prepared in the same manner as in Example 1. Observation of the alignment state of the liquid crystal cell with a polarizing microscope confirmed that the liquid crystal cell had a uniform alignment without any defect. When the voltage holding ratio of this TDA / p-PD liquid crystal cell was measured, it was 96% at 23 ° C. and 65% at 90 ° C.
And the NDA of Example 3 lower than 60%
The voltage holding ratio at high temperatures is lower than that of a liquid crystal cell using p-PD.

Example 4 The NDA / p-PD resin solution used in Example 1 was spin-coated at 2000 rpm on a glass substrate with a transparent electrode.
It was baked at 00 ° C. for 60 minutes to obtain a polyimide film having a thickness of 1000 °. The imidation ratio of this polyimide film was confirmed to be 50% from the IR spectrum.

A nematic liquid crystal (ZLI-2293 manufactured by Merck) was injected into the cell prepared in the same manner as in Example 1. Observation of the alignment state of the liquid crystal cell with a polarizing microscope confirmed that the liquid crystal cell had a uniform alignment without any defect. When the voltage holding ratio of this liquid crystal cell was measured, even when the imidation ratio was as low as 50%, it was 97 ° C at 23 ° C.
%, 84% at 70 ° C and 74% at 80 ° C.

Example 5 The NDA / p-PD resin solution used in Example 1 was spin-coated on a glass substrate with a transparent electrode at 2000 rpm, and
The resultant was baked at 50 ° C. for 60 minutes to obtain a polyimide film having a thickness of 1000 °. The imidation ratio of this polyimide film was confirmed to be 90% from the IR spectrum.

A liquid crystal (ZLI-2293 manufactured by Merck) was injected into the cell prepared in the same manner as in Example 1. Observation of the alignment state of the liquid crystal cell with a polarizing microscope confirmed that the liquid crystal cell had a uniform alignment without any defect. When the voltage holding ratio of this liquid crystal cell was measured,
At 98 ° C., 87% at 70 ° C., and 78% at 80 ° C.

Comparative Example 6 The TDA / p-PD solution used in Comparative Example 1 was spin-coated on a glass substrate with a transparent electrode at 3000 rpm, and
The resultant was baked at 60 ° C. for 60 minutes to obtain a polyimide film having a thickness of 1000 °. The imidation ratio of this polyimide film was confirmed to be 90% from the IR spectrum.

Thereafter, a liquid crystal (ZLI-2293 manufactured by Merck) was injected in the same manner as in Example 3, and a liquid crystal (Merck manufactured by Merck) was injected.
MLC-2003) was injected to prepare a liquid crystal cell. Observation of the alignment state of the liquid crystal cell with a polarizing microscope confirmed that the liquid crystal cell had a uniform alignment without any defect. When the voltage holding ratio of this liquid crystal cell was measured, the voltage holding ratio was 97% at 23 ° C., 70% at 70 ° C., and was low at 70 ° C.

COMPARATIVE EXAMPLE 7 The TDA / p-PD solution used in Comparative Example 5 was spin-coated at 3000 rpm on a glass substrate with a transparent electrode.
The resultant was baked at 60 ° C. for 60 minutes to obtain a polyimide film having a thickness of 1000 °. The imidation ratio of this polyimide film was confirmed to be 60% from the IR spectrum.

Thereafter, a liquid crystal (ZLI-2293 manufactured by Merck & Co.) was injected in the same manner as in Example 3 to prepare a liquid crystal cell. Observation of the alignment state of the liquid crystal cell with a polarizing microscope confirmed that the liquid crystal cell had a uniform alignment without any defect. When the voltage holding ratio of this liquid crystal cell was measured, the voltage holding ratio was 96% at 23 ° C., 68% at 70 ° C., and was low at 70 ° C.

Comparative Example 8 4,10-dioxatricyclo [6.3.1.0 <2,
7>] dodecane-3,5,9,11-tetraone (hereinafter abbreviated as TCA) 22.42 g (0.1 mol), p-P
10.81 g (0.1 mol) of D in 188 g of NMP
The reaction was carried out at room temperature for 3 hours to prepare a polyamic acid solution.
The reduced viscosity ηsp / c of the obtained resin is 1.3 dl / g.
(0.5% by weight NMP solution, 30 ° C.). This polyamic acid (TCA / p-PD) solution was treated with a solid content of 5%.
%, Diluted with NMP, spin-coated on a glass substrate with a transparent electrode at 4000 rpm, and heated at 350 ° C./60.
By firing for a minute, a polyimide film having a thickness of 1000 ° was obtained. The imidation ratio of this polyimide film was 47% from the IR spectrum.
Was confirmed.

Thereafter, a liquid crystal (ZLI-2293 manufactured by Merck & Co.) was injected in the same manner as in Example 3 to prepare a liquid crystal cell. Observation of the alignment state of the liquid crystal cell with a polarizing microscope confirmed that the liquid crystal cell had a uniform alignment without any defect. When the voltage holding ratio of this liquid crystal cell was measured, it was 98% at 23 ° C., 81% at 70 ° C., and 65% at 80 ° C.
And a high voltage holding ratio, but inferior to NDA / p-PD.

[0068]

According to the liquid crystal alignment treatment agent of the present invention, a liquid crystal alignment film having a higher voltage holding ratio than before can be obtained regardless of the imidization ratio, and an excellent liquid crystal element can be obtained.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takayasu Nihira 722-1, Tsuboi-cho, Funabashi-shi, Chiba Nissan Chemical Industry Co., Ltd. (72) Inventor Hideyuki Nawata 722-1, Tsuboi-cho, Funabashi-shi, Chiba Nissan Chemical (72) Inventor Kiyoshi Sawahata 722-1 Tsuboi-cho, Funabashi-shi, Chiba Pref. Nissan Chemical Industry Co., Ltd.

Claims (1)

[Claims] (1) The following formula (1): A tetracarboxylic acid and a derivative thereof containing at least 1 mol% or more of a tetracarboxylic dianhydride and a derivative thereof represented by the following formula (2): (In the formula (2), R represents a divalent organic group.) A polyamic acid produced by reacting with a diamine compound represented by the following formula:
A liquid crystal alignment treatment agent comprising at least one selected from polymers corresponding to the range of <a ≦ 100.