JP2618557B2 - Alignment agent for liquid crystal display device and liquid crystal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alignment agent for a liquid crystal display device and a liquid crystal display device. More specifically, the present invention relates to a liquid crystal display device having excellent storage stability and excellent adhesion to a silicon nitride surface which can be cured at a low temperature. The present invention relates to an alignment agent for a liquid crystal display element from which a liquid crystal alignment film can be obtained and a liquid crystal display element using the same.

[0002]

2. Description of the Related Art A liquid crystal display device is a display device utilizing the electro-optical change of liquid crystal, and is widely used as a display for a small computer, a word processor or the like because of its thinness, light weight and small power consumption. The most common liquid crystal display device currently used is to align nematic liquid crystal uniformly on an electrode substrate so that the long axis of the molecule is in a fixed direction, and to align the long axis of the liquid crystal molecule.
Twisted nematic type (hereinafter referred to as T) in which electrode substrates are combined so as to be twisted by 90 degrees or more.
It is a liquid crystal display element of a super twisted nematic type (hereinafter abbreviated as STN type) or a super twisted nematic type.

As described above, in the TN type and STN type liquid crystal display devices, it is important to orient the major axes of the liquid crystal molecules in a certain direction. There are two methods for aligning the liquid crystal molecules in this way: (a) a method in which an inorganic substance such as silicon oxide is vapor-deposited on a substrate, and (b) an alignment film that is an organic film is formed on the substrate and the surface thereof is formed. Rubbing in a certain direction with a cloth such as cotton, nylon, polyester, etc.
The method (b) is not industrially efficient due to cost and processing time, so the method (b) is used industrially.

[0004] As the organic film used here, polyvinyl alcohol, polyoxyethylene, polyamide,
Polyimides and the like have been studied, but polyimides are generally used at present from the viewpoints of orientation and chemical stability. As a method of forming a polyimide film as an alignment film on a substrate, a heating treatment is performed after coating an alignment agent in which a polyamic acid is dissolved in an organic solvent on a substrate, the solvent is volatilized, and the polyamic acid is dehydrated and closed by dehydration. Is generally used.

However, if the polyamic acid solution is left at room temperature for a long period of time, it changes in viscosity, making it difficult to process or severely gelling, making it unusable. It must be stored, requires a freezer warehouse, and takes time to return to room temperature during use. Furthermore, in recent years, the use of organic color filters for colorization of liquid crystal display elements and the use of plastic substrates have caused a problem that the high-temperature curing process of about 300 ° C. required for dehydration and ring closure of polyamic acid has an adverse effect. Has also arisen.

On the other hand, Japanese Patent Application Laid-Open Nos.
As described in JP 39525, a polyimide soluble in a solvent is synthesized even by dehydration and ring closure by using an aliphatic cyclic compound for the tetracarboxylic acid component, and the solvent is only volatilized at a temperature of about 200 ° C. Have been proposed. However, these soluble imide type alignment agents,
Poor adhesion to substrate compared to polyamic acid type,
In the rubbing process, there is a problem that the rubbing process may be peeled off from the substrate. In particular, in an active matrix type liquid crystal display element which has been put into practical use in recent years due to a demand for high image quality, there are irregularities of a switching element such as a transistor or a diode on a substrate surface, and corners of the element are easily peeled off. In addition, since many parts including these elements are coated with silicon nitride to which the polyimide resin is difficult to adhere, the problem related to the adhesion is serious.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an alignment agent for a liquid crystal display device which is excellent in storage stability and which can obtain a liquid crystal alignment film having an excellent adhesion to a silicon nitride surface which can be cured at a low temperature. To provide.

[0008]

According to the present invention, an imidation ratio is reduced.
1% by weight of a polymer (A) having a structure represented by the general formula (1) after heat treatment of 30% or more, and an imidation ratio of 30%
As described above, 0.001 to 0.25 parts by weight of a silicone imide compound having a structure represented by the general formula (2) after the heat treatment;
A liquid crystal display element comprising a liquid crystal display element comprising a solvent and an alignment film obtained by applying and heating the liquid crystal display element alignment agent.

[0009]

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[0010]

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[0011]

The alignment agent for a liquid crystal display element of the present invention has excellent storage stability, can be cured at a low temperature, and has good adhesion of a cured film, and in particular, generally does not easily adhere to a polyimide resin. It is to exhibit extremely excellent adhesion to the silicon nitride surface.

The major reason why excellent storage stability can be obtained is that the imidation ratio of the polymer (A) and the silicone imide compound is set to 30% or more. On the other hand, when the imidation ratio is less than 30%, the same viscosity change as that of a polyamic acid having an imidation ratio of 0% generally occurs, which is not preferable.

Further, since both the polymer (A) and the silicone imide compound have a flexible molecular structure,
Curing can be performed at about the same temperature, and does not have the adverse effect of high temperatures.

Further, a silicone imide compound can impart extremely excellent adhesion to a polyimide film by adding a small amount thereof. This is because the silicone component in the structure of the general formula (2) shows extremely good adhesion to silicon and a silicon compound, and the general formula (2) has an imide structure. This is because good compatibility with the coalescence is exhibited. However, silicone imide compounds
The product has a poor orientation when copolymerized with an acid anhydride having an alicyclic structure.
bad. A polymer having a structure represented by the general formula (1) and a general
A silicone imide compound having a structure represented by the formula (2)
Is blended in the range of 1: 0.001 to 0.25.
It shows good orientation and excellent adhesion.

For these reasons, the alignment agent for a liquid crystal display device of the present invention can provide a liquid crystal alignment film having excellent storage stability, capable of being cured at a low temperature, and having extremely excellent adhesion to a silicon nitride surface. Further, the liquid crystal display element of the present invention has high reliability without defects due to peeling of the alignment film.

The polymer (A) can be obtained by reacting a tetracarboxylic dianhydride having an alicyclic structure with a diamine compound in a polar organic solvent. Preferred examples of the tetracarboxylic dianhydride at this time include 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, cis ,
Cis, cis, cis-1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, bicyclo [2,2,2] oct-7-ene -2,3,5,6-
Examples include tetracarboxylic dianhydride and cyclobutanetetracarboxylic dianhydride, but are not particularly limited thereto. Further, preferred examples of the diamine compound include 4,4′-diaminodiphenylmethane and 4,4′-bis.
(4-aminophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 4,4 ′ -
Examples include, but are not limited to, diaminodiphenyl sulfone, 1,4-diaminocyclohexane, 4,4′-diaminodicyclohexylmethane, 1,3-bis (aminomethyl) cyclohexane, and hexamethylenediamine. Preferred examples of the solvent at this time include N, N-dimethylformamide, N, N-dimethylacetamide, N, N-dimethylacrylamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, cresol and the like. However, the present invention is not particularly limited to these.

The silicone imide compound can be obtained by reacting a tetracarboxylic dianhydride with a bis (aminopropyl) siloxane compound represented by the general formula (3) in a polar organic solvent.

[0018]

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Preferred examples of the tetracarboxylic dianhydride at this time include 5- (2,5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride. Cis, cis, cis, cis, cis-1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, bicyclo [2,2,2] oct -7-ene-2,3,5,6-tetracarboxylic dianhydride, cyclobutanetetracarboxylic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 4,4' -Oxydiphthalic dianhydride, pyromellitic dianhydride, 3,3 ', 4,4'-
Biphenyltetracarboxylic dianhydride, 2,2-bis (3,4-
(Dicarboxyphenyl) hexafluoropropane dianhydride, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride, and the like, but are not particularly limited thereto. Preferred examples of the solvent in this case include N, N-dimethylformamide, N, N-dimethylacetamide, N, N-dimethylacrylamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, cresol and the like. However, the present invention is not particularly limited to these.

The polymer (A) and the silicone imide compound are mixed in a solution state or a solid, and diluted to a predetermined concentration with a solvent to obtain an alignment agent for a liquid crystal display device. At this time, the silicone imide compound is mixed so as to be 0.001 to 0.25 parts by weight with respect to 1 part by weight of the polymer (A). When the amount of the silicone imide compound is less than 0.001 part by weight, sufficient adhesiveness cannot be obtained, and when the amount is more than 0.25 part by weight, the orientation of the liquid crystal deteriorates and good display cannot be obtained.

Preferred examples of the solvent for the aligning agent of the present invention include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, and γ-butyrolactone. It is not limited.

The orientation agent of the present invention can be used by applying it on a substrate provided with a transparent electrode by printing or spin coating, curing it by heating to 150 to 250 ° C., and then subjecting it to a rubbing treatment. Hereinafter, the present invention will be described in more detail with reference to examples.

[0023]

【Example】

(Example 1) (1) Synthesis (1-1) In a four-neck separable flask equipped with a thermometer, a stirrer, a raw material inlet, and a dry nitrogen gas inlet tube, 4,4'-
15.86 g of diaminodiphenylmethane (hereinafter abbreviated as DDM)
(0.08 mol) is dissolved in 200 g of N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP). 5- (2,5-
Dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride (hereinafter abbreviated to FMCDA)
21.15 g (0.08 mol) was added at once, and stirring was continued for 5 hours while maintaining at 20 ° C. to obtain a polyamic acid solution.

To this system, 20 g of toluene was added, the dry nitrogen gas inlet tube was removed, and instead a Dean starch reflux cooling tube was attached to raise the temperature of the system. The heating was continued while removing the water produced by the imidization out of the system by azeotropic distillation with toluene, and the reaction was allowed to proceed at 160 to 170 ° C., and the reaction was terminated after 3 hours. The resulting solution was dropped into 30 liters of methanol with stirring over 1 hour to precipitate the polymer, and only the solid content was recovered by filtration, followed by drying at 40 ° C. for 48 hours in a vacuum dryer. Was. The imidization ratio, was determined from the absorption based on imide rings appearing in the absorption and 1780 cm ^-1 based on the imidization before amide bond appearing at 1650 cm ^-1 measured FT-IR spectrum was 100%.

(1-2) In a four-neck separable flask equipped with a thermometer, a stirrer, a raw material inlet, and a dry nitrogen gas inlet tube, 21.15 g (0.08 mol) of FMCDAg is dissolved in 200 g of NMP. Under a flow of dry nitrogen gas, 1,3-bis (3-aminopropyl) tetramethyldisiloxane (hereinafter abbreviated as APDS) 19.88
g (0.08 mol) was dropped from the dropping funnel.
Stirring was continued for 5 hours while maintaining the temperature at ° C to obtain a silicone amic acid solution.

To this system, 20 g of toluene was added, the dry nitrogen gas inlet tube was removed, and instead a Dean starch reflux cooling tube was attached to raise the temperature of the system. Heating was continued while removing the water generated by the imidization by azeotropic distillation with toluene, the reaction was advanced at 160 to 170 ° C., the reaction was terminated after 3 hours, and the toluene was removed from the system under reduced pressure. . The resulting solution was added dropwise to 60 liters of cold water with stirring over 1 hour to precipitate the polymer, and only the solid content was recovered by filtration, followed by drying in a vacuum dryer at 40 ° C. for 48 hours. Was. The imidation ratio determined by FT-IR was 100%.

5.0 g of the polymer (1-1) and 0.5 g of the silicone imide compound of (1-2) were dissolved in 95.0 g of γ-butyrolactone to prepare an alignment agent for a liquid crystal display device.

(1/2) Evaluation of Characteristics The orientation agent synthesized in (1) was spin-coated on a silicon wafer coated with silicon nitride so as to have a thickness of 0.1 μm after curing, and then dried at 200 ° C. in a drier. Heat drying was performed for 1 hour.
This sample was evaluated for adhesion according to JIS D0202, and the ratio (number of peelings / total number) was 0/100, indicating good adhesion.

The alignment agent synthesized in (1) was spin-coated on a glass substrate with an ITO electrode so as to have a thickness of 0.1 μm after curing, and then heat-treated at 200 ° C. for 1 hour in a drier to perform a rubbing treatment. When a TN-type liquid crystal display device was manufactured using liquid crystal ZLI-1132 manufactured by Merck, the orientation of the liquid crystal was good. When the device was subjected to an acceleration test in which the device was held at 80 ° C. for 3 weeks, the orientation of the liquid crystal was good. The viscosity of this alignment agent at the time of synthesis was measured with an E-type viscometer.
The measured viscosity after storage at 23 ° C. for one month was 41 mPa · s, indicating good room temperature storage stability.

Example 2 (2) Synthesis In a four-neck separable flask equipped with a thermometer, a stirrer, a raw material inlet, and a dry nitrogen gas inlet tube, 3,3 ′, 4,4′-benzophenone tetra Carboxylic acid 25.78 g (hereinafter abbreviated as BTDA) (0.
08 mol) in 200 g of NMP. Under dry nitrogen gas inflow, 19.88 g (0.08 mol) of APDS was dropped from the dropping funnel,
After completion of the dropwise addition, stirring was continued for 5 hours while maintaining the temperature at 20 ° C. to obtain a silicone amic acid solution.

To this system, 60 g of toluene was added, and the dry nitrogen gas inlet tube was removed, and instead, a Dean starch reflux cooling tube was attached, and the temperature of the system was raised. The heating was continued while removing the water generated by the imidization out of the system by azeotropic distillation with toluene, the reaction was advanced at 140 to 145 ° C, and the reaction was terminated after 2 hours, and the toluene was removed out of the system under reduced pressure. . The resulting solution was added dropwise to 60 liters of cold water with stirring over 1 hour to precipitate the polymer, and only the solid content was recovered by filtration, followed by drying in a vacuum dryer at 40 ° C. for 48 hours. Was. The imidation ratio determined by FT-IR was 75%.

0.3 g of this silicone imide compound and 5.0 g of the polymer shown in (1-1) of Example 1 were dissolved in 95.0 g of γ-butyrolactone to prepare an aligning agent for a liquid crystal display device.

(2/2) Evaluation of Characteristics When evaluated in the same manner as in Example 1, the adhesion to the silicon nitride surface (number of peelings / total number) was 0/100, indicating good adhesion. In addition, the orientation of the liquid crystal when the liquid crystal display element was assembled was good, and the imidation ratio after heat treatment at 200 ° C. for 1 hour was 1
00%. When the device was subjected to an acceleration test in which the device was held at 80 ° C. for 3 weeks, the orientation of the liquid crystal was good. The viscosity of this aligning agent at the time of synthesis was 40 mPa · s when measured with an E-type viscometer, and the viscosity after storage at 23 ° C. for one month was 42 mPa · s, showing good room temperature storage stability. showed that.

Example 3 (3) Synthesis (3-1) 1,3-bis (amino) was placed in a four-neck separable flask equipped with a thermometer, a stirrer, a material inlet, and a dry nitrogen gas inlet tube. Methyl) cyclohexane 11.38 g (0.08 mol)
Dissolve in 200 g of NMP. Under dry nitrogen gas inflow, 16.81 g (0.08 mol) of cis, cis, cis, cis-1,2,3,4-cyclopentanetetracarboxylic anhydride was added all at once, and stirring was continued for 5 hours while maintaining the temperature at 20 ° C. Thus, a polyamic acid solution was obtained.

To this system, 20 g of toluene was added, and the dry nitrogen gas inlet tube was removed, and a Dean starch reflux cooling tube was attached instead, and the temperature of the system was raised. The heating was continued while removing the water produced by the imidization out of the system by azeotropic distillation with toluene, and the reaction was allowed to proceed at 160 to 170 ° C., and the reaction was terminated after 3 hours. The resulting solution was dropped into 30 liters of methanol with stirring over 1 hour to precipitate the polymer, and only the solid content was recovered by filtration, followed by drying at 40 ° C. for 48 hours in a vacuum dryer. Was. The imidation ratio determined by FT-IR was 75%.

(3-2) In a four-neck separable flask equipped with a thermometer, stirrer, material inlet, and dry nitrogen gas inlet tube, 21.15 g (0.08 mol) of FMCDAg is dissolved in 200 g of NMP. Under the flow of dry nitrogen gas, 44.24 g (0.08 mol) of a silicone diamine represented by the formula (4) was dropped from a dropping funnel,
After completion of the dropwise addition, stirring was continued for 5 hours while maintaining the temperature at 20 ° C. to obtain a silicone amic acid solution.

[0037]

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To this system, 20 g of toluene was added, the dry nitrogen gas inlet tube was removed, and instead a Dean starch reflux cooling tube was attached to raise the temperature of the system. The heating was continued while removing the water produced by the imidization out of the system by azeotropic distillation with toluene, the reaction was allowed to proceed at 160 to 170 ° C, and the reaction was terminated after 2 hours, and the toluene was removed out of the system under reduced pressure. . The resulting solution was added dropwise to 60 liters of cold water with stirring over 1 hour to precipitate the polymer, and only the solid content was recovered by filtration, followed by drying in a vacuum dryer at 40 ° C. for 48 hours. Was. The imidation ratio determined by FT-IR was 100%.

5.0 g of the polymer shown in (3-1) and (3
-2) 0.4 g of the silicone imide compound was dissolved in 95.0 g of γ-butyrolactone to give an alignment agent for a liquid crystal display device.

(3/2) Evaluation of Characteristics When evaluated in the same manner as in Example 1, the adhesion to the silicon nitride surface (number of peelings / total number) was 0/100, indicating good adhesion. In addition, the orientation of the liquid crystal when the liquid crystal display element was assembled was good, and the imidation ratio after heat treatment at 200 ° C. for 1 hour was 1
00%. When the device was subjected to an acceleration test in which the device was held at 80 ° C. for 3 weeks, the orientation of the liquid crystal was good. The viscosity of this aligning agent at the time of synthesis was measured by an E-type viscometer to be 40 mPa · s, and the viscosity after storage at 23 ° C. for one month was 41 mPa · s. Demonstrated stability.

Example 4 (4) Synthesis (4-1) In a four-neck separable flask equipped with a thermometer, a stirrer, a raw material inlet, and a dry nitrogen gas inlet tube, DDM15.
86 g (0.08 mol) are dissolved in 200 g of NMP. Under dry nitrogen gas inflow, 19.86 g (0.08 mol) of bicyclo [2,2,2] oct-7-ene-2,3,5,6-tetracarboxylic anhydride was added at a stretch, and the temperature was kept at 20 ° C. for 5 hours. Stirring was continued for an hour to obtain a polyamic acid solution.

To this system, 20 g of toluene was added, the dry nitrogen gas inlet tube was removed, and instead a Dean starch reflux cooling tube was attached to raise the temperature of the system. The heating was continued while removing the water produced by the imidization out of the system by azeotropic distillation with toluene, and the reaction was allowed to proceed at 160 to 170 ° C., and the reaction was terminated after 3 hours. The resulting solution was dropped into 30 liters of methanol with stirring over 1 hour to precipitate the polymer, and only the solid content was recovered by filtration, followed by drying at 40 ° C. for 48 hours in a vacuum dryer. Was.

(4-2) 25.78 g (0.08 mol) of BTDA is dissolved in 200 g of NMP in a four-neck separable flask equipped with a thermometer, a stirrer, a raw material inlet, and a dry nitrogen gas inlet tube. Under a flow of dry nitrogen gas, 97.13 (0.08 mol) of the silicone diamine represented by the formula (5) was added dropwise from the dropping funnel. After completion of the addition, stirring was continued for 5 hours while maintaining the temperature at 20 ° C. to obtain a silicone amic acid solution.

[0044]

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To this system, 60 g of toluene was added, the dry nitrogen gas inlet tube was removed, and a Dean starch reflux cooling tube was attached instead, and the temperature of the system was raised. The heating was continued while removing the water generated by the imidization out of the system by azeotropic distillation with toluene, the reaction was advanced at 140 to 145 ° C, and the reaction was terminated after 2 hours, and the toluene was removed out of the system under reduced pressure. . The resulting solution was added dropwise to 60 liters of cold water with stirring over 1 hour to precipitate the polymer, and only the solid content was recovered by filtration, followed by drying in a vacuum dryer at 40 ° C. for 48 hours. Was. The imidation ratio determined by FT-IR was 80%.

5.0 g of the polymer shown in (4-1) and (4-
0.2 g of the silicone imide compound shown in 2) was dissolved in 95.0 g of γ-butyrolactone to prepare an alignment agent for a liquid crystal display device.

(4/2) Evaluation of Characteristics When evaluated in the same manner as in Example 1, the adhesion to the silicon nitride surface (number of peelings / total number) was 0/100, indicating good adhesion. In addition, the orientation of the liquid crystal when the liquid crystal display element was assembled was good, and the imidation ratio after heat treatment at 200 ° C. for 1 hour was 1
00%. When the device was subjected to an acceleration test in which the device was held at 80 ° C. for 3 weeks, the orientation of the liquid crystal was good. The viscosity of this aligning agent at the time of synthesis was 40 mPa · s when measured with an E-type viscometer, and the viscosity after storage at 23 ° C. for one month was 42 mPa · s, showing good room temperature storage stability. showed that.

Comparative Example 1 5.0 g of the polymer synthesized in (1-1) of Example 1 was dissolved in 95.0 g of γ-butyrolactone to prepare an aligning agent for a liquid crystal display device. When the adhesion was evaluated in the same manner as in Example 1, (the number of peelings / total number) was 76/100.
And the adhesion to the silicon nitride surface was insufficient.

Comparative Example 2 5.0 g of the polymer synthesized in (1-1) of Example 1 and 0.2 g of aminopropyltriethoxysilane were added.
4 g was dissolved in 95.0 g of γ-butyrolactone to give an alignment agent for a liquid crystal display device. When the adhesion was evaluated in the same manner as in Example 1, (the number of peelings / total number) was 7/100, and the adhesion to the silicon nitride surface was insufficient. When the TN type liquid crystal display element was manufactured, the initial orientation was good,
After holding at 80 ° C. for 3 weeks, disclination lines were partially observed, and the orientation was insufficient.

Comparative Example 3 (1) Synthesis In Example 1, 3.0 g of the polymer synthesized in (1-1) and 2.0 g of the silicone imide compound synthesized in (1-2) were γ
-The same procedure was carried out except that the compound was dissolved in 95.0 g of butyrolactone and used as an alignment agent for a liquid crystal display device.

(2) Evaluation of Characteristics When the evaluation was performed in the same manner as in Example 1, the adhesion (number of peelings / total number) was as good as 0/100, but the TN type liquid crystal display element was manufactured. In addition, disclination lines were observed on the entire surface, and the orientation was insufficient.

Comparative Example 4 (1) Synthesis 21.15 g (0.08 mol) of FMCDA was added to pyromellitic dianhydride.
A polyamic acid solution was obtained in the same manner as in Example 1 except that the amount was changed to 45 g (0.08 mol). Since it was found that the polymer was insolubilized when toluene was added and heated and dehydrated in the same manner as in Example 1, the polyamic acid solution was diluted with NMP so that the resin content became 5%, and used as an aligning agent for liquid crystal display elements. .

(2) Evaluation of Characteristics When the characteristics were evaluated in the same manner as in Example 1, the adhesion (the number of peelings / total number) was 0/100, which was good. The initial orientation was good, but after holding at 80 ° C. for 3 weeks, disclination lines were partially observed, and the orientation was insufficient. The imidation ratio after heat treatment at 200 ° C. for 1 hour was 60%. The viscosity during synthesis is
The viscosity after storage at 23 ° C for one month was 1
It was 4 mPa · s.

Each of the alignment agents for liquid crystal display elements of Examples 1 to 4 shows good adhesion and storage stability at room temperature. In addition, the imidation ratio after treatment at 200 ° C. for 1 hour is 100%, which indicates that low-temperature curing is possible. In Comparative Example 1, since no silicone imide compound was contained, the adhesion to the silicon nitride surface was insufficient. In Comparative Example 2, aminopropyltriethoxysilane, which is a general silane coupling agent, was added, but the adhesion was insufficient and the orientation was insufficient as compared with the examples. In Comparative Example 3, since the content of the silicone imide compound was as large as 0.6 times that of the polymer represented by the general formula (1), the adhesion was sufficient, but the orientation was insufficient. In Comparative Example 4, since no group having an alicyclic structure was used for R ₁ in the general formula (1), the imidation ratio after heat treatment at 200 ° C. for 1 hour was 60%.
Since low-temperature curing was impossible, the orientation was insufficient. Also, the imidization rate cannot be 30% or more,
As a result, storage stability was also insufficient.

[0055]

The alignment agent for a liquid crystal display device of the present invention has excellent storage stability, can be stored at room temperature for one month or more, and can be cured at a relatively low temperature of about 200 ° C. when used. . Furthermore, because of its excellent adhesion to the silicon nitride surface,
A liquid crystal display element of the present invention having an alignment film obtained by applying and heat-treating the liquid crystal display element of the present invention, which is an alignment agent for a liquid crystal display element that improves the yield in the manufacturing process and also has excellent reliability, It has excellent durability.

Claims (2)

(57) [Claims] 1. An imidation ratio of 30% or more, and 1 part by weight of a polymer (A) having a structure represented by the general formula (1) after heat treatment, and an imidation ratio of 30% or more. An alignment agent for a liquid crystal display device, comprising 0.001 to 0.25 parts by weight of a silicone imide compound having a structure represented by the general formula (2) after heat treatment, and a solvent. Embedded image Embedded image 2. A liquid crystal display device having an alignment film obtained by applying the liquid crystal display device alignment agent according to claim 1 and performing a heat treatment.