JPH10123532A - Orientation treating agent for liquid crystal cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an orientation treating agent for a liquid crystal cell with which a liquid crystal oriented film having a low graded orientation angle stable to a heat treatment is obtainable and a uniform liquid crystal display of a high contrast is obtainable and the orientation treating agent for the liquid crystal cell which is the orientation treating agent for the liquid crystal cell obtd. by using feroelectric liquid crystals or antiferroelectric liquid crystals and which uniformly controls the orientation state of the liquid crystals. SOLUTION: At least part of the diamine component of the orientation treating agent for the liquid crystal cell consisting essentially of a tetracarboxylic acid deriv. component and the polyimide and/or polyimide precursor obtd. by bringing the diamine component into reaction polymn. is the diamine component expressed by the formula (where, (n) is an integer from 1 to 12) and imparts the graded orientation angle of <=2 deg. to the nematic liquid crystals.

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 cell, and more particularly, to a liquid crystal cell in which a nematic liquid crystal molecule has a low tilt alignment angle with respect to a substrate and has a tilt alignment angle in a heat treatment after liquid crystal injection. The present invention relates to an alignment treatment agent for a liquid crystal cell which shows good alignment stability without change and also has excellent alignment uniformity with respect to ferroelectric liquid crystals and antiferroelectric liquid crystals.

[0002]

2. Description of the Related Art A liquid crystal display element is a display element utilizing electro-optical change of liquid crystal, and is small and light in terms of a device.
Attention has been paid to characteristics such as low power consumption, and in recent years, display devices for various displays have been remarkably developed. Above all, using nematic liquid crystal having positive dielectric anisotropy, liquid crystal molecules are arranged parallel to the substrate at each interface of a pair of electrode substrates facing each other, and the orientation directions of the liquid crystal molecules are orthogonal to each other. A twisted nematic (TN type) field effect type liquid crystal display element combining both substrates is a typical example thereof.

In such a TN-type liquid crystal display device, the major axis direction of the liquid crystal molecules must be uniformly aligned in parallel with the substrate surface, and the liquid crystal molecules must be aligned with a constant tilt alignment angle with respect to the substrate. is important. As a typical method for aligning liquid crystal molecules in this manner, two methods have been conventionally known. A first method is a method in which an inorganic substance such as silicon oxide is obliquely vapor-deposited on a substrate to form an inorganic film on the substrate, and liquid crystal molecules are aligned in a vapor deposition direction. In this method, a stable orientation having a fixed tilt orientation angle can be obtained, but it is not industrially efficient. The second method is a method in which an organic film is formed on the substrate surface, the surface is rubbed in a certain direction with a cloth such as cotton, nylon, or polyester, and the liquid crystal molecules are aligned in the rubbing direction. In this method, a stable orientation can be obtained relatively easily, and therefore, this method is exclusively used industrially.
Examples of the organic film include polyvinyl alcohol, polyoxyethylene, polyamide, and polyimide. Among them, polyimide is most commonly used in terms of chemical stability, thermal stability, and the like. A typical example of polyimide used for such a liquid crystal alignment film is disclosed in
There is one disclosed in Japanese Patent No. 47932.

On the other hand, using a ferroelectric liquid crystal or an antiferroelectric liquid crystal having a chiral smectic phase, liquid crystal molecules are oriented in one direction with respect to the substrate at each interface between a pair of electrode substrates facing each other. In the ferroelectric and antiferroelectric liquid crystal display elements arranged in a matrix, the direct interaction between the spontaneous polarization of the liquid crystal molecules and the electric field makes the high-speed response and high field of view superior to the nematic liquid crystal display element. It is known to have angular properties. In addition, in the case of surface-stable ferroelectric liquid crystal devices and cell-stable antiferroelectric liquid crystal devices in which the cell gap is thinner than the helical pitch of ferroelectric liquid crystals and antiferroelectric liquid crystals, nematic liquid crystal display devices It is known that a high-definition display element can be manufactured even with a simple matrix electrode structure, showing no bistability or tri-stability.

In such ferroelectric liquid crystal devices and antiferroelectric liquid crystal devices, it is extremely important to uniformly align liquid crystal molecules in a certain direction. As a typical method of aligning the liquid crystal in this way, as in the case of a nematic liquid crystal display element, an inorganic material such as silicon oxide is vapor-deposited obliquely to form an inorganic film on a substrate, and an induction film is formed on the substrate surface. A method is known in which the surface is rubbed in a certain direction with a cloth. As an organic film to be rubbed,
As with the nematic liquid crystal display device, polyimide is generally used in terms of chemical stability, thermal stability, and the like. However, conventional polyimides have not always been able to provide a sufficiently satisfactory orientation for ferroelectric liquid crystals or antiferroelectric liquid crystals. Even if a good orientation is obtained, there is a problem in the synthesis of polyimide, which is a problem in practical use.

[0006]

SUMMARY OF THE INVENTION A nematic liquid crystal having a positive dielectric anisotropy is used. At each interface between a pair of opposing electrode substrates, liquid crystal molecules are arranged parallel to the substrate. In a TN field-effect type liquid crystal display device in which both substrates are combined so that the alignment directions are orthogonal to each other, the major axis direction of the liquid crystal molecules is aligned uniformly and parallel to the substrate surface, and the liquid crystal molecules are further aligned on the substrate. On the other hand, it is important to orient with a certain tilt orientation angle.
Particularly in recent years, in a TN-type field-effect liquid crystal display device,
In order to improve the contrast, it is required to stably obtain a low tilt orientation angle of 2 ° or less.

However, a conventional liquid crystal alignment film using polyimide exhibits a low tilt angle after tilting the liquid crystal, but is heated to a temperature higher than the isotropic temperature of the liquid crystal (hereinafter referred to as isotropic treatment). ) In some cases, the tilt orientation angle changes. In addition, there is also a problem that the isotropic treatment lowers the tilt alignment angle and disturbs the alignment of liquid crystal molecules.
These problems are extremely important in achieving even higher contrast and uniform liquid crystal display in a future liquid crystal display device, and provide a stable low tilt angle of 2 ° or less to heat treatment. A polyimide alignment film has been desired.

On the other hand, in a ferroelectric liquid crystal element and an antiferroelectric liquid crystal element, it is extremely important to obtain a uniform initial alignment of the liquid crystal, and it is known that this alignment state greatly affects the performance of the liquid crystal element. Have been. However, it is difficult to control the alignment state of ferroelectric liquid crystal and antiferroelectric liquid crystal uniformly. Generally, alignment defects such as zigzag defects are observed on a rubbed polyimide film, and this is a cause of liquid crystal elements such as a decrease in contrast. There is a problem that the performance of the device is significantly reduced. An aliphatic diamine having an alkylene group in the main chain as disclosed in JP-A-8-248424 can be used as an alignment film for well aligning ferroelectric liquid crystals. However, such an aliphatic diamine is inferior in polymerization reactivity and has a problem in obtaining a certain polyimide varnish.

It is an object of the present invention to provide a liquid crystal alignment film having a low tilt alignment angle that is stable against heat treatment in a liquid crystal cell alignment treatment agent using a nematic liquid crystal, and provides a high contrast and uniform liquid crystal display. Liquid crystal cell alignment treatment agent and a liquid crystal cell alignment treatment agent using a ferroelectric liquid crystal or an anti-ferroelectric liquid crystal, the liquid crystal cell alignment treatment agent for uniformly controlling the alignment state of the liquid crystal. On offer.

[0010]

SUMMARY OF THE INVENTION The present invention relates to an alignment agent for a liquid crystal cell using a nematic liquid crystal. As a result of detailed and systematic intensive studies on the alignment treatment agent for cells, the present invention has been completed.

That is, the present invention provides an alignment treatment agent for a liquid crystal cell containing a polyimide and / or a polyimide precursor obtained by reacting and polymerizing a tetracarboxylic acid derivative component and a diamine component. Partly the following formula (1)

[0012]

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Wherein n is a diamine represented by the formula (1), and which gives a tilt alignment angle of 2 ° or less to the nematic liquid crystal. Things.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The diamine represented by the formula (1) used in the present invention is generally synthesized as follows. After dissolving α, ω-dihalogenoalkane and nitrophenol in acetonitrile at a molar ratio of 1: 2, the mixture is refluxed at 80 ° C. in the presence of potassium carbonate to obtain a dinitro compound. The dinitro compound is reduced to obtain a diamine represented by the formula (1). Examples of the reduction method include a catalytic hydrogenation method using a palladium-carbon (Pd / C) catalyst at room temperature.

The liquid crystal aligning agent according to the present invention comprises a polyimide having a specific diamine structure and / or a polyimide precursor, and a resin solution obtained by dissolving the same in an organic polar solvent is coated on a substrate having a transparent electrode. After drying,
A polyimide resin film is formed by baking, and then the film surface is subjected to an alignment treatment such as a rubbing treatment to be used as a liquid crystal alignment film.

The liquid crystal aligning agent of the present invention has a nematic liquid crystal molecule having a low tilt alignment angle with respect to a substrate, has a good alignment property in which the tilt alignment angle does not change during heat treatment, and has the above-mentioned properties. When the liquid crystal alignment treatment agent is used as an alignment treatment agent for ferroelectric liquid crystals and antiferroelectric liquid crystals, it has good alignment properties. The tetracarboxylic dianhydrides and derivatives thereof used in the present invention include pyromellitic acid, benzophenone tetracarboxylic acid, aromatic tetracarboxylic acids such as biphenyltetracarboxylic acid and naphthalenetetracarboxylic acid, and dianhydrides thereof and these. Dicarboxylic diacid halide, furthermore,
Cyclobutanetetracarboxylic acid, cyclopentanetetracarboxylic acid, cyclohexanetetracarboxylic acid and 3,
4-dicarboxy-1,2,3,4-tetrahydro-1
-Alicyclic tetracarboxylic acids such as naphthalene succinic acid and the like and dianhydrides thereof, dicarboxylic acid diacid halides thereof, aliphatic tetracarboxylic acids such as butanetetracarboxylic acid and the like, dianhydrides thereof and dicarboxylic acids thereof And diacid halides. Among them, it is particularly preferable to use an aromatic tetracarboxylic acid such as pyromellitic acid or cyclobutanetetracarboxylic acid in order to sufficiently obtain the effects of the present invention.

These tetracarboxylic acids and their derivatives may be used singly or as a mixture of two or more. Equation (1)

[0018]

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The diamine component represented by the formula (where n is an integer of 1 to 12) is represented by the formula (2)

[0020]

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A bis (4-aminophenoxy) alkane represented by the formula (where n is an integer of 1 to 12) is practically preferable. N in the formulas (1) and (2) is preferably 1 to since the heat resistance of the obtained polyimide decreases as n increases.
12, preferably 1 to 10, more preferably 1 to 8.

Specific examples of the formula (2) include bis (4-aminophenoxy) methane, 1,2-bis (4-aminophenoxy) ethane, 1,3-bis (4-aminophenoxy) propane, 4-bis (4-aminophenoxy)
Butane, 1,5-bis (4-aminophenoxy) pentane, 1,6-bis (4-aminophenoxy) hexane,
1,7-bis (4-aminophenoxy) heptane, 1,
8-bis (4-aminophenoxy) octane, 1,9-
Bis (4-aminophenoxy) nonane, 1,10-bis (4-aminophenoxy) decane and the like can be mentioned.

In particular, 1,3-bis (4-aminophenoxy) propane, 1,4-bis (4-aminophenoxy)
Butane, 1,5-bis (4-aminophenoxy) pentane, 1,6-bis (4-aminophenoxy) hexane,
1,7-bis (4-aminophenoxy) heptane, 1,
8-Bis (4-aminophenoxy) octane is preferred. The proportion of the diamine component represented by the formula (1) in the total diamine component is not particularly limited as long as it is within a range that gives a low tilt angle of 2 ° or less to the nematic liquid crystal. 50 to 100 represented by 1)
mol%, preferably 70-100 mol%, especially 8
5 to 100 mol%.

Examples of the diamine other than the diamine component represented by the formula (1) in the present invention include 2,5-diaminotoluene, 2,6-diaminotoluene, 4'-diaminobiphenyl, 3,
3′-dimethyl-4, 4′-diaminobiphenyl, 3,
3'-dimethoxy-4,4'-diaminobiphenyl, diaminodiphenylether, 2,2'-diaminodiphenylpropane, bis (3,5-diethyl-4-aminophenyl) methane, diaminodiphenylsulfone, diaminobenzophenone, diamino Naphthalene, 1,4-bis (4-aminophenoxy) benzene, 1,4-bis (4
-Aminophenyl) benzene, 9,10-bis (4-aminophenyl) anthracene, 1,3-bis (4-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) diphenylsulfone, 2,2 -Bis [4-
Aromatic diamines such as (4-aminophenoxy) phenyl] propane; alicyclic diamines such as bis (4-aminocyclohexyl) methane and bis (4-amino-3-methylcyclohexyl) methane;

[0025]

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(M is an integer of 1 to 10). Also, one or more of these diamines can be used in combination. Tetracarboxylic dianhydride and a diamine are reacted and polymerized to obtain a polyimide precursor. In this case, a tetracarboxylic dianhydride is generally used as a tetracarboxylic acid derivative. 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 (in N-methylpyrrolidone at a temperature of 30 ° C., a concentration of 0.5 dl / d) in terms of reduced viscosity of the polyimide precursor solution.
l) is preferable.

As a method for reacting and polymerizing a tetracarboxylic dianhydride and a primary diamine, a solution method is generally preferred. Specific examples of the solvent used in the solution polymerization method include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, Examples thereof include dimethyl sulfone, hexamethylphosphoramide, and butyl lactone. These may be used alone or as a mixture. Further, even if the solvent does not dissolve the polyimide resin precursor, the solvent may be used in addition to the above solvent within a range where a uniform solution can be obtained. At that time, the reaction temperature was -20.
Any temperature from ℃ to 150 ° C, preferably from -5 ° C to 100 ° C can be selected.

In order to convert the polyimide resin precursor into a polyimide resin, a method of dehydrating and ring-closing by heating is employed. As this heat dehydration ring closure temperature, any temperature of 150 ° C to 450 ° C, preferably 170 ° C to 350 ° C can be selected. The time required for this dehydration ring closure depends on the reaction temperature, but is suitably 30 seconds to 10 hours, preferably 5 minutes to 5 hours.

In the case of a so-called soluble polyimide in which the polyimide is dissolved in an organic solvent, a polyimide precursor obtained by reacting a tetracarboxylic dianhydride with a primary diamine is used in a solution by using a known dehydration ring-closing catalyst. It can be imidized. The polyimide resin solution thus obtained can be used as it is, or can be used after being dissolved again in a poor solvent such as methanol or ethanol.

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, diglyme and the like.

The polyimide and / or polyimide precursor solution of the present invention obtained as described above is applied to a transparent substrate such as glass or plastic with a transparent electrode by using a method such as spin coating or transfer printing. It is applied and heat-treated under the above conditions to form a polyimide film. At this time, the thickness of the polyimide film is not particularly limited, but is suitably set to 100 to 3,000 when used as a normal liquid crystal alignment film. Next, the resin film is subjected to an alignment treatment such as a rubbing treatment, and can be used as a liquid crystal alignment treatment agent. Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

[0033]

【Example】

Example 1 1,4-bis (4-aminophenoxy) butane 22.8
g (0.1 mol) and 19.2 g (0.098 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride in N-methylpyrrolidone (hereinafter abbreviated as NMP) 34
The reaction was carried out at room temperature for 10 hours in 3.5 g to prepare a polyimide precursor (polyamic acid) solution. The polymerization reaction proceeds easily and uniformly, and the reduced viscosity is 0.9 dl / g (concentration 0.5
g / dl, 30 ° C. in NMP).

This solution was added with NMP to a total solid content of 4% by weight.
After diluting, a glass substrate was spin-coated at 3500 rpm, and then heat-treated at 80 ° C. for 5 minutes and at 250 ° C. for 1 hour to form a polyimide resin film having a thickness of 1000 °. After rubbing this coating film with a cloth, the rubbing direction was antiparallel sandwiched by a 50 μm spacer, and the assembly was performed to obtain a nematic liquid crystal (ZLI-2293 manufactured by Merck).
Was injected to form a liquid crystal cell.

When the alignment state of the liquid crystal cell was observed with a polarizing microscope, it was confirmed that the liquid crystal cell had a uniform alignment without any defect. Further, when the tilt orientation angle of the liquid crystal was measured for this cell by the crystal rotation method, it was 1.0 °, which was a low and stable tilt orientation angle. Further, this liquid crystal cell is
After heat treatment in an oven at 0 ° C. for 1 hour, the alignment state was observed with a polarizing microscope, and it was confirmed that the alignment was uniform without defects. Further about this cell,
When the tilt orientation angle of the liquid crystal was measured by the crystal rotation method,
1.0 °, which was a low tilt orientation angle.

Example 2 1,5-bis (4-aminophenoxy) pentane
2 g (0.1 mol) and 19.2 g (0.098 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride
To N-methylpyrrolidone (hereinafter abbreviated as NMP) 34
The reaction was carried out at room temperature for 10 hours in 3.5 g to prepare a polyimide precursor (polyamic acid) solution. The polymerization reaction proceeds easily and uniformly, and the reduced viscosity is 0.8 dl / g (concentration 0.5
g / dl, 30 ° C. in NMP).

This solution was added with NMP to a total solid content of 4% by weight.
After diluting, a glass substrate was spin-coated at 3500 rpm, and then heat-treated at 80 ° C. for 5 minutes and at 250 ° C. for 1 hour to form a polyimide resin film having a thickness of 1000 °. After rubbing this coating film with a cloth, the rubbing direction was antiparallel sandwiched by a 50 μm spacer, and the assembly was performed to obtain a nematic liquid crystal (ZLI-2293 manufactured by Merck).
Was injected to form a liquid crystal cell.

When the alignment state of the liquid crystal cell was observed with a polarizing microscope, it was confirmed that the liquid crystal cell had a uniform alignment without any defect. Further, when the tilt orientation angle of the liquid crystal of this cell was measured by a crystal rotation method, it was 0.9 °, which was a low tilt orientation angle. Further, the liquid crystal cell was heated at 120 ° C.
After heat treatment in an oven for one hour, the alignment state was observed with a polarizing microscope, and it was confirmed that the alignment was uniform without defects. Further, when the tilt orientation angle of the liquid crystal of this cell was measured by the crystal rotation method,
゜, which was a low and stable tilt orientation angle.

Example 3 1,9-bis (4-aminophenoxy) nonane 34.2
g (0.1 mol) and 19.2 g (0.098 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride
With N-methylpyrrolidone (hereinafter abbreviated as NMP) 30
In 2.6 g, the mixture was reacted at room temperature for 10 hours to prepare a polyimide precursor (polyamic acid) solution. The polymerization reaction proceeds easily and uniformly, and the reduced viscosity is 0.75 dl / g (at a concentration of 0.1 dl / g).
A polyimide precursor (5 g / dl, 30 ° C. in NMP) was obtained.

This solution was added with NMP to a total solid content of 4% by weight.
After dilution, the glass substrate was spin-coated at 3000 rpm, and then heat-treated at 80 ° C. for 5 minutes and at 250 ° C. for 1 hour to form a polyimide resin film having a thickness of 1000 °. After rubbing this coating film with a cloth, the rubbing direction was anti-parallel sandwiched with a spacer of 50 μm, and the assembly was performed to obtain a nematic liquid crystal (ZLI-229 manufactured by Merck).
3) was injected to prepare a liquid crystal cell.

When the alignment state of the liquid crystal cell was observed with a polarizing microscope, it was confirmed that the liquid crystal cell had a uniform alignment without any defect. Further, when the tilt orientation angle of the liquid crystal of this cell was measured by a crystal rotation method, it was 0.9 °, which was a low tilt orientation angle. Further, the liquid crystal cell was heated at 120 ° C.
After heat treatment in an oven for one hour, the alignment state was observed with a polarizing microscope, and it was confirmed that the alignment was uniform without defects. Further, with respect to this cell, when the tilt orientation angle of the liquid crystal was measured by a crystal rotation method,
゜, which was a low and stable tilt orientation angle.

Example 4 1,12-bis (4-aminophenoxy) dodecane 3
8.4 g (0.1 mol) and 19.2 g (0.098 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride were mixed with N-methylpyrrolidone (hereinafter abbreviated as NMP).
The reaction was performed at room temperature for 10 hours in 326.4 g to prepare a polyimide precursor (polyamic acid) solution. The polymerization reaction proceeded easily and uniformly, and a polyimide precursor having a reduced viscosity of 0.70 dl / g (concentration: 0.5 g / dl, 30 ° C. in NMP) was obtained.

This solution was diluted with NMP to a total solid content of 4% by weight, spin-coated on a glass substrate at 2800 rpm, and then heat-treated at 80 ° C. for 5 minutes and 250 ° C. for 1 hour to obtain a polyimide resin having a thickness of 1000 mm. A film was formed. After rubbing this coating film with a cloth, the rubbing direction was anti-parallel sandwiched with a spacer of 50 μm, and the assembly was performed to obtain a nematic liquid crystal (ZLI-229 manufactured by Merck).
3) was injected to prepare a liquid crystal cell.

When the alignment state of the liquid crystal cell was observed with a polarizing microscope, it was confirmed that the liquid crystal cell had a uniform alignment without any defect. Further, when the tilt angle of the liquid crystal of this cell was measured by the crystal rotation method, it was 1.7 °, which was a low tilt angle. Further, the liquid crystal cell was heated at 120 ° C.
After heat treatment in an oven for one hour, the alignment state was observed with a polarizing microscope, and it was confirmed that the alignment was uniform without defects. Further, when the tilt orientation angle of the liquid crystal of this cell was measured by a crystal rotation method, it was 1.7.
゜, which was a low and stable tilt orientation angle.

Example 5 1,5-bis (4-aminophenoxy) pentane
1 g (0.05 mol), 10.1 g (0.05 mol) of diaminodiphenyl ether, and 19.2 g (0.09 g) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride
8 mol) in 234.6 g of N-methylpyrrolidone (hereinafter abbreviated as NMP) at room temperature for 10 hours to prepare a polyimide precursor (polyamic acid) solution. The polymerization reaction proceeds easily and uniformly, and the reduced viscosity is 0.86 dl / g
A polyimide precursor having a concentration of 0.5 g / dl and a temperature of 30 ° C. in NMP was obtained.

This solution was added with NMP to a total solid content of 4% by weight.
After diluting, a glass substrate was spin-coated at 3500 rpm, and then heat-treated at 80 ° C. for 5 minutes and at 250 ° C. for 1 hour to form a polyimide resin film having a thickness of 1000 °. After rubbing this coating film with a cloth, the rubbing direction was antiparallel sandwiched by a 50 μm spacer, and the assembly was performed to obtain a nematic liquid crystal (ZLI-2293 manufactured by Merck).
Was injected to form a liquid crystal cell.

When the alignment state of the liquid crystal cell was observed with a polarizing microscope, it was confirmed that the liquid crystal cell had a uniform alignment without any defect. Further, the tilt orientation angle of the liquid crystal of this cell measured by the crystal rotation method was 1.9 °, which was a low tilt orientation angle. Further, the liquid crystal cell was heated at 120 ° C.
After heat treatment in an oven for one hour, the alignment state was observed with a polarizing microscope, and it was confirmed that the alignment was uniform without defects. Further, with respect to this cell, the tilt orientation angle of the liquid crystal was measured by a crystal rotation method.
゜, which was a low and stable tilt orientation angle.

Example 6 1,5-bis (4-aminophenoxy) pentane19.
4 g (0.08 mol), 4 g (0.02 mol) of diaminodiphenyl ether, and 19.2 g (0.098 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride were mixed with N-methylpyrrolidone (hereinafter referred to as N-methylpyrrolidone). (Abbreviated as NMP)
The reaction was carried out at room temperature for 10 hours in 241.4 g to prepare a polyimide precursor (polyamic acid) solution. The polymerization reaction proceeded easily and uniformly, and a polyimide precursor having a reduced viscosity of 0.86 dl / g (concentration: 0.5 g / dl, in NMP at 30 ° C.) was obtained.

This solution was added with NMP to a total solid content of 4% by weight.
After diluting, a glass substrate was spin-coated at 4000 rpm, and then heat-treated at 80 ° C. for 5 minutes and 250 ° C. for 1 hour to form a polyimide resin film having a thickness of 1000 °. After rubbing this coating film with a cloth, the rubbing direction was antiparallel sandwiched by a 50 μm spacer, and the assembly was performed to obtain a nematic liquid crystal (ZLI-2293 manufactured by Merck).
Was injected to form a liquid crystal cell.

When the alignment state of the liquid crystal cell was observed with a polarizing microscope, it was confirmed that the liquid crystal cell was uniformly aligned without any defect. Further, when the tilt angle of the liquid crystal of this cell was measured by the crystal rotation method, it was 1.7 °, which was a low tilt angle. Further, the liquid crystal cell was heated at 120 ° C.
After heat treatment in an oven for one hour, the alignment state was observed with a polarizing microscope, and it was confirmed that the alignment was uniform without defects. Further, when the tilt orientation angle of the liquid crystal of this cell was measured by a crystal rotation method, it was 1.7.
゜, which was a low and stable tilt orientation angle.

Example 7 1,4-bis (4-aminophenoxy) butane 22.8
g (0.1 mol) and 21.8 g of pyromellitic dianhydride
(0.096 mol) with N-methylpyrrolidone (hereinafter NM)
The reaction was carried out at room temperature for 10 hours in 252.7 g of P) to prepare a polyimide precursor (polyamic acid) solution. The polymerization reaction proceeds easily and uniformly and has a reduced viscosity of 0.9
A polyimide precursor of 2 dl / g (concentration 0.5 g / dl, 30 ° C. in NMP) was obtained.

This solution was subjected to NMP to a total solid content of 4% by weight.
After diluting, a glass substrate was spin-coated at 4000 rpm, and then heat-treated at 80 ° C. for 5 minutes and 250 ° C. for 1 hour to form a polyimide resin film having a thickness of 1000 °. After rubbing this coating film with a cloth, the rubbing direction was antiparallel sandwiched by a 50 μm spacer, and the assembly was performed to obtain a nematic liquid crystal (ZLI-2293 manufactured by Merck).
Was injected to form a liquid crystal cell.

When the alignment state of the liquid crystal cell was observed with a polarizing microscope, it was confirmed that the alignment was uniform with no defects. Further, when the tilt orientation angle of the liquid crystal of this cell was measured by a crystal rotation method, it was 0.9 °, which was a low tilt orientation angle. Further, the liquid crystal cell was heated at 120 ° C.
After heat treatment in an oven for one hour, the alignment state was observed with a polarizing microscope, and it was confirmed that the alignment was uniform without defects. Further, with respect to this cell, when the tilt orientation angle of the liquid crystal was measured by a crystal rotation method,
゜, which was a low and stable tilt orientation angle.

Example 8 1,7-bis (4-aminophenoxy) heptane
4 g (0.1 mol) and 19.2 g (0.098 mol) of 1,2,3,4, -cyclobutanetetracarboxylic dianhydride were mixed with N-methylpyrrolidone (hereinafter abbreviated as NMP).
The reaction was performed at room temperature for 10 hours in 286.7 g to prepare a polyimide precursor (polyamic acid) solution. The polymerization reaction proceeded easily and uniformly, and a polyimide precursor having a reduced viscosity of 0.76 dl / g (concentration: 0.5 g / dl, 30 ° C. in NMP) was obtained with good reproducibility.

This solution was added with NMP to a total solid content of 4% by weight.
After diluting, a glass substrate was spin-coated at 3000 rpm, and then heat-treated at 80 ° C. for 5 minutes and at 250 ° C. for 1 hour to form a polyimide resin film having a thickness of 1000 °. After rubbing this coating film with a cloth, the rubbing direction was antiparallel sandwiched by a 50 μm spacer, and the assembly was performed to obtain a nematic liquid crystal (ZLI-2293 manufactured by Merck).
Was injected to form a liquid crystal cell.

When the alignment state of the liquid crystal cell was observed with a polarizing microscope, it was confirmed that the liquid crystal cell had a uniform alignment without any defect. Further, the tilt orientation angle of the liquid crystal of this cell was measured by a crystal rotation method and found to be 1.0 °, which was a low tilt orientation angle. Further, the liquid crystal cell was heated at 120 ° C.
After heat treatment in an oven for one hour, the alignment state was observed with a polarizing microscope, and it was confirmed that the alignment was uniform without defects. Further, when the tilt orientation angle of the liquid crystal of this cell was measured by the crystal rotation method,
゜, which was a low and stable tilt orientation angle. Example 9 1,5-bis (4-aminophenoxy) pentane24.
2 g (0.1 mol) and pyromellitic dianhydride 21.8
g (0.096 mol) of N-methylpyrrolidone (hereinafter referred to as N
The reaction was carried out at room temperature for 10 hours in 260.6 g of MP to prepare a polyimide precursor (polyamic acid) solution. The polymerization reaction proceeds easily and uniformly and has a reduced viscosity of 0.9
4 dl / g (concentration 0.5 g / dl, 30 ° C. in NMP)
Was obtained with good reproducibility.

This solution was added with NMP to a total solid content of 4% by weight.
After that, the glass substrate was spin-coated at 4500 rpm, and then heat-treated at 80 ° C. for 5 minutes and 250 ° C. for 1 hour to form a polyimide resin film having a thickness of 1000 °. After rubbing this coating film with a cloth, the rubbing direction was antiparallel sandwiched by a 50 μm spacer, and the assembly was performed to obtain a nematic liquid crystal (ZLI-2293 manufactured by Merck).
Was injected to form a liquid crystal cell.

When the alignment state of the liquid crystal cell was observed with a polarizing microscope, it was confirmed that the liquid crystal cell had a uniform alignment without any defect. Further, when the tilt orientation angle of the liquid crystal of this cell was measured by a crystal rotation method, it was 0.9 °, which was a low tilt orientation angle. Further, the liquid crystal cell was heated at 120 ° C.
After heat treatment in an oven for one hour, the alignment state was observed with a polarizing microscope, and it was confirmed that the alignment was uniform without defects. Further, with respect to this cell, when the tilt orientation angle of the liquid crystal was measured by a crystal rotation method,
゜, which was a low and stable tilt orientation angle.

Example 10 The same polyimide precursor (polyamic acid) solution as in Example 1 was prepared. That is, 22.8 g (0.1 mole) of 1,4-bis (4-aminophenoxy) butane and 1,2,3
19.2 g of 4-cyclobutanetetracarboxylic dianhydride
(0.098 mol) with N-methylpyrrolidone (hereinafter NM)
The mixture was reacted at room temperature in 343.5 g for 10 hours to prepare a polyimide precursor (polyamic acid) solution. The polymerization reaction proceeds easily and uniformly and has a reduced viscosity of 0.9
A dl / g (concentration: 0.5 g / dl, 30 ° C. in NMP) polyimide precursor was obtained.

This solution was diluted with NMP to a total solid content of 4% by weight in the same manner as in Example 1, and then applied to a glass substrate at 3500 rpm.
m, and then heat-treated at 80 ° C. for 5 minutes and 250 ° C. for 1 hour to form a polyimide resin film having a thickness of 1000 °. After this film was rubbed with a cloth, each rubbed substrate was assembled with the rubbing direction parallel with a 2 μm spacer in between, and then a ferroelectric smectic liquid crystal (CS-101 manufactured by Chisso Corporation) was assembled.
4) was injected to prepare a surface-stabilized liquid crystal cell. When the orientation state of this cell was observed with a polarizing microscope,
No defects were observed over the entire area of the liquid crystal cell, confirming that the ferroelectric liquid crystal was uniformly oriented.

Example 11 The same polyimide precursor (polyamic acid) solution as in Example 2 was prepared. That is, 24.2 g (0.1 mol) of 1,5-bis (4-aminophenoxy) pentane and 1,2,2
3,4-cyclobutanetetracarboxylic dianhydride
2 g (0.098 mol) was reacted in 343.5 g of N-methylpyrrolidone (hereinafter abbreviated as NMP) at room temperature for 10 hours to prepare a polyimide precursor (polyamic acid) solution. The polymerization reaction proceeds easily and uniformly and has a reduced viscosity of 0.1.
A polyimide precursor of 8 dl / g (concentration 0.5 g / dl, 30 ° C. in NMP) was obtained.

This solution was diluted with NMP to a total solid content of 4% by weight in the same manner as in Example 2, and the solution was applied to a glass substrate at 3500 rpm.
m, and then heat-treated at 80 ° C. for 5 minutes and 250 ° C. for 1 hour to form a polyimide resin film having a thickness of 1000 °. After this film was rubbed with a cloth, each rubbed substrate was assembled with the rubbing direction parallel with a 2 μm spacer in between, and then a ferroelectric smectic liquid crystal (CS-101 manufactured by Chisso Corporation) was assembled.
4) was injected to prepare a surface-stabilized liquid crystal cell. When the orientation state of this cell was observed with a polarizing microscope,
No defects were observed over the entire area of the liquid crystal cell, confirming that the ferroelectric liquid crystal was uniformly oriented.

Example 12 The same polyimide precursor (polyamic acid) solution as in Example 3 was prepared. That is, 34.2 g (0.1 mol) of 1,9-bis (4-aminophenoxy) nonane and 1,2,3,
19.2 g of 4-cyclobutanetetracarboxylic dianhydride
(0.098 mol) with N-methylpyrrolidone (hereinafter NM)
In 302.6 g of the mixture, the mixture was reacted at room temperature for 10 hours to prepare a polyimide precursor (polyamic acid) solution. The polymerization reaction proceeds easily and uniformly and has a reduced viscosity of 0.7
5 dl / g (concentration 0.5 g / dl, 30 ° C. in NMP)
Was obtained.

This solution was diluted with NMP to a total solid content of 4% by weight in the same manner as in Example 3, and then applied to a glass substrate at 3000 rpm.
m, and then heat-treated at 80 ° C. for 5 minutes and 250 ° C. for 1 hour to form a polyimide resin film having a thickness of 1000 °. After this film was rubbed with a cloth, each rubbed substrate was assembled with the rubbing direction parallel with a 2 μm spacer in between, and then a ferroelectric smectic liquid crystal (CS-101 manufactured by Chisso Corporation) was assembled.
4) was injected to prepare a surface-stabilized liquid crystal cell. When the orientation state of this cell was observed with a polarizing microscope,
No defects were observed over the entire area of the liquid crystal cell, confirming that the ferroelectric liquid crystal was uniformly oriented.

Example 13 The same polyimide precursor (polyamic acid) solution as in Example 7 was prepared. That is, 22.8 g (0.1 mol) of 1,4-bis (4-aminophenoxy) butane and 21.8 g (0.096 mol) of pyromellitic dianhydride were mixed with N-methylpyrrolidone (hereinafter abbreviated as NMP). ) In 252.7 g,
The mixture was reacted at room temperature for 10 hours to prepare a polyimide precursor (polyamic acid) solution. The polymerization reaction proceeds easily and uniformly, and the reduced viscosity is 0.92 dl / g (concentration: 0.5 g / dl,
(30 ° C. in NMP) to obtain a polyimide precursor.

This solution was diluted with NMP to a total solid content of 4% by weight in the same manner as in Example 7, and then applied to a glass substrate at 4000 rpm.
m, and then heat-treated at 80 ° C. for 5 minutes and 250 ° C. for 1 hour to form a polyimide resin film having a thickness of 1000 °. After this coating film was rubbed with a cloth, each rubbed substrate was assembled with the rubbing direction parallel with a 2 μm spacer in between, and then a ferroelectric smectic liquid crystal (CS-101, manufactured by Chisso Corporation).
4) was injected to prepare a surface-stabilized liquid crystal cell. When the orientation state of this cell was observed with a polarizing microscope,
No defects were observed over the entire area of the liquid crystal cell, confirming that the ferroelectric liquid crystal was uniformly oriented.

Example 14 The same polyimide precursor (polyamic acid) solution as in Example 8 was prepared. That is, 31.4 g (0.1 mol) of 1,7-bis (4-aminophenoxy) heptane and 1,2,2
3,4, -cyclobutanetetracarboxylic dianhydride 1
9.2 g (0.098 mol) of N-methylpyrrolidone (hereinafter abbreviated as NMP) in 286.7 g at room temperature.
The reaction was carried out for a time to prepare a polyimide precursor (polyamic acid) solution. The polymerization reaction proceeds easily and uniformly, and the reduced viscosity is 0.76 dl / g (concentration: 0.5 g / dl, 3
0 ° C.) with good reproducibility.

This solution was diluted with NMP to a total solid content of 4% by weight in the same manner as in Example 8, and then applied to a glass substrate at 3000 rpm.
m, and then heat-treated at 80 ° C. for 5 minutes and 250 ° C. for 1 hour to form a polyimide resin film having a thickness of 1000 °. After this coating film was rubbed with a cloth, each rubbed substrate was assembled with the rubbing direction parallel with a 2 μm spacer in between, and then a ferroelectric smectic liquid crystal (CS-101, manufactured by Chisso Corporation).
4) was injected to prepare a surface-stabilized liquid crystal cell. When the orientation state of this cell was observed with a polarizing microscope,
No defects were observed over the entire area of the liquid crystal cell, confirming that the ferroelectric liquid crystal was uniformly oriented.

Example 15 The same polyimide precursor (polyamic acid) solution as in Example 9 was prepared. That is, 24.2 g (0.1 mol) of 1,5-bis (4-aminophenoxy) pentane and 21.8 g (0.096 mol) of pyromellitic dianhydride were added to N-
Methylpyrrolidone (hereinafter abbreviated as NMP) 260.6
g, a reaction was performed at room temperature for 10 hours to prepare a polyimide precursor (polyamic acid) solution. The polymerization reaction proceeds easily and uniformly, and the reduced viscosity is 0.94 dl / g (concentration 0.5 g
/ Dl, 30 ° C in NMP) with good reproducibility.

This solution was diluted with NMP to a total solid content of 4% by weight in the same manner as in Example 9, and then 4500 r was added to the glass substrate.
pm, then 250 ° C. for 5 minutes at 80 ° C.
For 1 hour to form a polyimide resin film having a thickness of 1000 °. After rubbing this coating film with a cloth, each rubbed substrate was assembled with the rubbing direction parallel with a 2 μm spacer in between, and then a ferroelectric smectic liquid crystal (CS-10, manufactured by Chisso Corporation) was assembled.
14) was injected to produce a surface stabilized liquid crystal cell.
Observation of the orientation state of the cell with a polarizing microscope revealed no defects over the entire area of the liquid crystal cell, confirming that the ferroelectric liquid crystal was uniformly oriented.

Comparative Example 1 20.0 g (0.1 mol) of diaminodiphenyl ether
And 1,2,3,4-cyclobutanetetracarboxylic dianhydride (19.2 g, 0.098 mol) in N-methylpyrrolidone (hereinafter abbreviated as NMP) in 343.5 g at room temperature for 10 hours to obtain a polyimide precursor Body (polyamic acid)
A solution was prepared. The polymerization reaction proceeds easily and uniformly, and the reduced viscosity is 0.98 dl / g (concentration: 0.5 g / dl, NMP
30 ° C.). This solution is NM
After diluting to a total solid content of 3% by weight with P, 30
Spin coating at 00 rpm, then at 80 ° C. for 5 minutes, 2
By heating at 50 ° C for 1 hour, the thickness is 1000Å
Was formed. After this coating film was rubbed with a cloth, the rubbing direction was antiparallel sandwiched with a spacer of 50 μm, assembled, and a nematic liquid crystal (ZLI-2293 manufactured by Merck) was injected to prepare a liquid crystal cell.

When the alignment state of the liquid crystal cell was observed with a polarizing microscope, it was confirmed that the liquid crystal cell had a uniform alignment without any defect. Further, with respect to this cell, the tilt orientation angle of the liquid crystal was measured by a crystal rotation method and found to be 3.6 °.
Further, after the liquid crystal cell was heated in an oven at 120 ° C. for 1 hour, the alignment state was observed with a polarizing microscope. As a result, it was found that the liquid crystal cell had a uniform alignment without any defect. The measured tilt orientation angle was 4.1 °, and the heat treatment increased the tilt orientation angle. After the heat treatment, a low tilt orientation angle was not obtained.

Comparative Example 2 2,4 g (0.1 mol) of 4,4'-diamino-3,3'-dimethyldicyclohexylmethane and 1,2,3,4
-Cyclobutanetetracarboxylic dianhydride 19.2 g
(0.098 mol) with N-methylpyrrolidone (hereinafter NM)
The mixture was reacted at room temperature in 343.5 g for 10 hours to prepare a polyimide precursor (polyamic acid) solution. The polymerization reaction proceeds easily and uniformly and has a reduced viscosity of 0.7
A polyimide precursor of 8 dl / g (concentration 0.5 g / dl, 30 ° C. in NMP) was obtained.

This solution was added with NMP to a total solid content of 4% by weight.
After diluting, a glass substrate was spin-coated at 3500 rpm, and then heat-treated at 80 ° C. for 5 minutes and at 250 ° C. for 1 hour to form a polyimide resin film having a thickness of 1000 °. After rubbing this coating film with a cloth, the rubbing direction was antiparallel sandwiched by a 50 μm spacer, and the assembly was performed to obtain a nematic liquid crystal (ZLI-2293 manufactured by Merck).
Was injected to form a liquid crystal cell.

When the alignment state of the liquid crystal cell was observed with a polarizing microscope, it was confirmed that the liquid crystal cell had a uniform alignment without any defect. Further, for this cell, the tilt orientation angle of the liquid crystal measured by the crystal rotation method was 3.8 °.
After the liquid crystal cell was heated in an oven at 120 ° C. for 1 hour, the alignment state was observed with a polarizing microscope.

Comparative Example 3 20.0 g (0.1 mol) of diaminodiphenyl ether
And 1,2,3,4-cyclobutanetetracarboxylic dianhydride (19.2 g, 0.098 mol) in N-methylpyrrolidone (hereinafter abbreviated as NMP) in 343.5 g at room temperature for 10 hours to obtain a polyimide precursor Body (polyamic acid)
A solution was prepared. The polymerization reaction proceeds easily and uniformly, and the reduced viscosity is 0.98 dl / g (concentration: 0.5 g / dl, NMP
30 ° C.).

This solution was diluted with NMP to a total solid content of 3% by weight, spin-coated on a glass substrate at 3000 rpm, and then heat-treated at 80 ° C. for 5 minutes and at 250 ° C. for 1 hour to obtain a polyimide resin having a thickness of 1000 mm. A film was formed. After this film was rubbed with a cloth, each rubbed substrate was assembled with the rubbing direction parallel with a 2 μm spacer in between, and then a ferroelectric smectic liquid crystal (CS-1014 manufactured by Chisso Corporation) was injected. Thus, a surface stabilized liquid crystal cell was manufactured. Observation of the orientation state of the cell by a polarizing microscope revealed that many zigzag defects and linear defects were observed, and the orientation of the ferroelectric liquid crystal was non-uniform.

Comparative Example 4 22.6 g (0.1 mol) of 4,4'-diamino-3,3'-dimethyldicyclohexylmethane and 1,2,3,4
19.2 g of cyclobutanetetracarboxylic dianhydride
(0.098 mol) with N-methylpyrrolidone (hereinafter NM)
The mixture was reacted at room temperature in 343.5 g for 10 hours to prepare a polyimide precursor (polyamic acid) solution. The polymerization reaction proceeds easily and uniformly and has a reduced viscosity of 0.7
A polyimide precursor of 8 dl / g (concentration 0.5 g / dl, 30 ° C. in NMP) was obtained.

This solution was diluted with NMP to a total solid content of 4% by weight, spin-coated on a glass substrate at 3500 rpm, and then heat-treated at 80 ° C. for 5 minutes and at 250 ° C. for 1 hour to obtain a polyimide resin having a thickness of 1000 mm. A film was formed. After this film was rubbed with a cloth, each rubbed substrate was assembled with the rubbing direction parallel with a 2 μm spacer in between, and then a ferroelectric smectic liquid crystal (CS-1014 manufactured by Chisso Corporation) was injected. Thus, a surface stabilized liquid crystal cell was manufactured. Observation of the orientation state of the cell by a polarizing microscope revealed that many zigzag defects and linear defects were observed, and the orientation of the ferroelectric liquid crystal was non-uniform.

Comparative Example 5 11.6 g (0.1 mol) of 1,6-diaminohexane and 19.2 g (0.098 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride were mixed with N-methyl. Pyrrolidone (hereinafter abbreviated as NMP) in 174.5 g at room temperature
The reaction was allowed to proceed for 0 hour to prepare a polyimide precursor (polyamic acid) solution. However, the polymerization reaction is 1,6-
Due to the high basicity of diaminohexane, a salt was formed and did not proceed uniformly. Furthermore, even when the amount of the acid anhydride used is the same, a salt is formed due to the high basicity of 1,6-diaminohexane, and the formation of the salt is not quantitative, so that the viscosity differs at each polymerization. Was obtained. As an example of polyimide precursors of different viscosities,
Reduced viscosity 0.5 dl / g (concentration 0.5 g / dl, NMP
30 ° C.).

This solution was treated with NMP to a total solid content of 6% by weight.
After diluting, a glass substrate was spin-coated at 3000 rpm, and then heat-treated at 80 ° C. for 5 minutes and at 250 ° C. for 1 hour to form a polyimide resin film having a thickness of 1000 °. After rubbing this coating film with a cloth, the rubbing direction was antiparallel sandwiched by a 50 μm spacer, and the assembly was performed to obtain a nematic liquid crystal (ZLI-2293 manufactured by Merck).
Was injected to form a liquid crystal cell.

When the alignment state of the liquid crystal cell was observed with a polarizing microscope, it was confirmed that the liquid crystal cell had a uniform alignment without any defect. Further, the tilt orientation angle of the liquid crystal of this cell measured by a crystal rotation method was 1.9 °.
Further, after the liquid crystal cell was heated in an oven at 120 ° C. for 1 hour, the alignment state was observed with a polarizing microscope. As a result, it was found that the liquid crystal cell had a uniform alignment without any defect. When the tilt orientation angle was measured, it was 2.5 °, and the heat treatment increased the tilt orientation angle. After the heat treatment, a low tilt orientation angle was not obtained.

Comparative Example 6 11.6 g (0.1 mol) of 1,6-diaminohexane and 19.2 g (0.098 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride were added to N-methyl Pyrrolidone (hereinafter abbreviated as NMP) in 174.5 g at room temperature
The reaction was allowed to proceed for 0 hour to prepare a polyimide precursor (polyamic acid) solution. The polymerization reaction formed a salt due to the high basicity of 1,6-diaminohexane, and did not proceed uniformly. Furthermore, even when the amount of the acid anhydride used is the same, a salt is formed due to the high basicity of 1,6-diaminohexane, and the formation of the salt is not quantitative, so that the viscosity differs at each polymerization. Was obtained. As an example of polyimide precursors of different viscosities, the reduced viscosity is 0.1.
A polyimide precursor of 5 dl / g (concentration 0.5 g / dl, 30 ° C. in NMP) was obtained.

This solution was treated with NMP to a total solid content of 6% by weight.
After diluting, a glass substrate was spin-coated at 3000 rpm, and then heat-treated at 80 ° C. for 5 minutes and at 250 ° C. for 1 hour to form a polyimide resin film having a thickness of 1000 °. After this film was rubbed with a cloth, each rubbed substrate was assembled with the rubbing direction parallel with a 2 μm spacer in between, and then a ferroelectric smectic liquid crystal (CS-1014 manufactured by Chisso Corporation) was injected. hand,
A surface stabilized liquid crystal cell was manufactured. Observation of the orientation state of the cell with a polarizing microscope revealed no defects over the entire area of the liquid crystal cell, confirming that the ferroelectric liquid crystal was uniformly oriented. However, although the orientation of the ferroelectric liquid crystal is good, 1,6-diaminohexane has a high basicity and forms a salt, and the formation of the salt is not quantitative. Since a polyimide precursor was obtained, it was difficult to prepare a polyimide precursor having good reproducibility.

[0085]

According to the liquid crystal alignment treating agent of the present invention, it is possible to obtain a thermally stable and excellent liquid crystal alignment film having a low tilt alignment angle, and to obtain a liquid crystal element having a higher contrast than before. . Further, by using the liquid crystal alignment treatment agent according to the present invention, a ferroelectric liquid crystal display device and an antiferroelectric liquid crystal display device exhibit excellent characteristics.

Continued on the front page (72) Inventor Hiroyoshi Fukuro 722-1, Tsuboi-cho, Funabashi-shi, Chiba Pref. Nissan Chemical Industry Co., Ltd. Central Research Laboratory

Claims (3)

[Claims] 1. An alignment treatment agent for a liquid crystal cell containing a polyimide and / or a polyimide precursor as a main component, which is obtained by reacting and polymerizing a tetracarboxylic acid derivative component and a diamine component. (1) (Wherein, n is an integer of 1 to 12) a diamine component, which gives a tilt alignment angle of 2 ° or less to a nematic liquid crystal. 2. The alignment agent for a liquid crystal cell according to claim 1, wherein the diamine represented by the formula (1) in the diamine component accounts for 50 mol% or more of all the diamine components. 3. The alignment agent for a liquid crystal cell according to claim 1, wherein the tetracarboxylic acid derivative component is at least one tetracarboxylic acid derivative selected from an aromatic tetracarboxylic acid derivative and a cyclobutanetetracarboxylic acid derivative.