JPH01262528A - Composition for liquid crystal orienting agent - Google Patents

Abstract

PURPOSE:To obtain the orienting agent for a liquid crystal cell which is large in the oblique orientation angle of a liquid crystal and has uniform coatability by incorporating a specific polyimide resin precursor and specific diimide compd. precursor as a compsn. for the liquid crystal orienting agent. CONSTITUTION:This compsn. contains the polyimide resin precursor having the repeating unit expressed by formula I (in formula I, R1 denotes an org. group constituting tetracarboxylic acid or the deriv. thereof; R2 denotes a divalent org. group constituting diamine) and the diimide compd. precursor expressed by formula II (in formula II, R3 denotes an org. group constituting tetracarboxylic acid or the deriv. thereof; R4, R5 denote an org. group constituting monoamine having an alkyl group of 6-20C or the deriv. thereof). The amt. of diimide compd. precursor expressed by formula II is used usually at 0.1-100wt.% of the polyimide resin precursor expressed by formula I. The oblique orientation angle of the liquid crystal is thereby increased and the uniform coatability is obtd. when the compsn. is coated on a substrate.

Description

Detailed description of the invention (a) Industrial application field The present invention relates to a composition for a liquid crystal aligning agent,
More specifically, the present invention relates to a composition used as an alignment treatment agent for liquid crystal cells, in which liquid crystal molecules have an increased oblique alignment angle with respect to a substrate, and have excellent uniformity.

(b) Conventional technology Organic resin films such as polyimide resin films have conventionally been used as substrate processing agents for aligning nematic liquid crystal molecules almost parallel to a transparent substrate such as glass or plastic film with transparent electrodes. Most commonly used.

In this case, by rubbing the organic resin film formed on the substrate in a certain direction with a cloth, the liquid crystal molecules are aligned in the rubbing direction, and at the same time, the liquid crystal tilt orientation angle is usually about 1 to 3 degrees with respect to the substrate surface. known to occur.

Furthermore, as a method for greatly tilting liquid crystal molecules, a method has conventionally been used in which an inorganic film such as silicon oxide is deposited on a substrate.

(c) Problems to be Solved by the Invention With the conventional method of rubbing an organic resin film formed on a substrate, it is difficult to achieve a large tetrahedral orientation of liquid crystal molecules.

In addition, the method of vapor depositing M-detachment on the substrate is more complicated than the rubbing method, and is not necessarily an appropriate method for actual industrial production.

(d) Means for solving the problems As a means for solving the above problems, Japanese Patent Laid-Open No. 62-262
No. 829 proposes the use of a composition comprising a polyimide resin precursor and a monoamine having a long-chain alkyl group as a liquid crystal aligning agent.

According to this method, it has become possible to increase the tilt orientation angle of the liquid crystal by the rubbing treatment.

However, the compatibility of the polyimide precursor constituting the above composition with the monoamine having a long-chain alkyl group is not necessarily sufficient, and when applied to a substrate as a liquid crystal aligning agent, problems may arise in uniform application. However, it was not always satisfactory when considering industrial production.

The present inventors have completed the present invention as a result of diligent efforts and studies to solve the above problems.

That is, the present invention provides a repeating unit represented by the general formula (1) (wherein R represents an i group constituting a tetracarboxylic acid or a derivative thereof, and R2 represents a divalent organic group constituting a diamine) A polyimide resin precursor having the general formula (n) (wherein, R1 represents an a group constituting a tetracarboxylic acid or a derivative thereof, and R, R, represents a monoamine having an alkyl group having 6 to 20 carbon atoms. The present invention relates to a composition for a liquid crystal aligning agent containing a diimide compound precursor represented by the following formula.

The composition of the present invention can be used as an alignment treatment agent for liquid crystal cells by coating it on a transparent substrate such as glass or plastic film with transparent electrodes, forming a polyimide resin film after curing, and then subjecting it to a rubbing treatment. can do.

The polyimide 1 resin precursor of the general formula ([) used in the composition of the present invention is represented by the general formula (III) (wherein R1 represents a tetravalent organic group constituting a tetracarboxylic acid, and R, Each of the four bonded carbonyl groups is directly bonded to a separate carbon atom.) One or more compounds selected from tetracarboxylic acids and their derivatives represented by formula (IV) 11□ N
-Rg-N++t (■)(
In the formula, R2 represents a divalent organic group constituting the diamine.

) It is obtained by reacting the diamine represented by

The reaction conditions are not particularly limited, and any method for obtaining a polyimide resin precursor may be used.

For example, using tetracarboxylic dianhydride as the tetracarboxylic acid and its derivative of formula -1 (I[[]), formula -C (rV ) is most preferable.Furthermore, the molar ratio of the tetracarboxylic dianhydride and diamine to be reacted is 0.
．． 5 to 2, preferably 0.9 to 1.1, and as in normal polycondensation reactions, the closer the molar ratio of these two components is to 1, the greater the molecular weight of the polyimide resin precursor produced.

The reaction temperature for producing polyimide resin precursor is -20~
The temperature is 150°C, preferably -5 to 100°C.

The diimide compound precursor of general formula [■] used in the composition of the present invention is -FIQ formula (V) (wherein, R3 represents a tetravalent organic group constituting a tetracarboxylic acid, and is bonded to R1. (4 carbonyl groups are directly bonded to separate carbon atoms.) One or more compounds selected from tetracarboxylic acids and their derivatives represented by formula (■) and general formula [ ■] R4-Ni1□ (Vl)
1?5-1111□ [■
It is obtained by reacting a monoamine represented by the formula (in the formula, R,, R, represents 1g constituting a monoamine having an alkyl group having 6 to 20 carbon atoms).

The reaction conditions are not particularly limited, and any method similar to the method for obtaining the polyimide resin precursor may be used.

For example, in a polar solvent such as dimethylformamide, dimethylacetamide, or N-methylpyrrolidone, the tetracarboxylic acid of formula (V) and the number of moles of the monoamine of general (Vl) and [~1] It is best to carry out the reaction so that the molar ratio of the acid dianhydride is 1=l:l.

The reaction temperature for producing the diimide compound precursor is -20
-150'C1, preferably -5 to 100°C.

The generated diimide compound precursor solution may be used as it is, or may be poured into a large excess of water or a poor solvent such as methanol, and the diimide compound precursor may be precipitated and recovered for use.

The tetracarboxylic acids and derivatives thereof of general formula (I[I) and general formula (V) may be the same or different from each other.

Specific examples thereof include aromatic tetracarboxylic acids such as biromellisic 1-acid, benzophenonetetracarboxylic acid, 3,4.3'', 4'-biphenyltetracarboxylic acid, their dianhydrides, and their dicarboxylic and diconic acids. Halides, aliphatic tetracarboxylic acids such as cyclobutanetetracarboxylic acid, cyclopentanetetracarboxylic acid, and cyclohexanetetracarboxylic acid, and their dianhydrides, and aliphatic compounds such as dicarboxylic acid halides, butanetetracarboxylic acid, etc. Examples include tetracarboxylic acids, their dianhydrides, and their dicarboxylic acid halides.

Further, the tetracarboxylic acid and its derivatives of formula (V) -C ([[IL-1) may be used alone or in combination of two or more.

-S Specific examples of the diamine of formula (IV) include ρ-phenylenediamine, m-phenylenediamine, diaminodiphenylmethane, diaminodiphenyl ether, 2.2
-diaminodiphenylpropane, diaminodiphenylsulfone, diaminobenzophenone, diaminonaphthalene, 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(4-aminophenyl)propane, 1
．． 1. Aromatic diamines such as 1.1.3,3.3-hexafluoro-2,2-bis(4-(4-aminophenoxy)phenyl)propane, and diaminosiloxanes such as:

Other alicyclic diamines and aliphatic diamines may be used depending on the purpose.

Further, these diamines may be used alone or in combination of two or more.

R= of the monoamine of general formula (Vl) and general formula [■],
Rs may be the same or different.

Specific examples include n-hexylamine, n-octylamine, n-decylamine, n-dodecylamine, n-
- Aliphatic amines such as hexadecylamine, 1,3-dimethylbutylamine, 1,5-dimethylhexylamine and 2-ethylhexylamine, p-aminophenylhexane, p-aminophenyl octane, p-aminophenyldodecane, p- Aminophenylhexadecane, p-
Aromatic amines such as aminophenoxyoctane, p-aminophenoxydodecane, and p-aminophenoxyhexadecane are mentioned.

Further, these monoamines can be used alone or in combination of two or more.

When the number of carbon atoms in R4 and R5, which are alkyl groups of the monoamine of general formula (n), is 5 or less, the effect of increasing the tilt orientation angle of liquid crystal molecules is not sufficient.

Furthermore, if the number of carbon atoms in R4 and R2 exceeds 20, problems such as poor applicability to a substrate tend to occur.

-Ffa The amount of the diimide compound precursor of formula (II) to be used is usually 0.00% relative to the polyimide resin precursor of general formula (I).
1~100 heavy view% usage weight.

The amount of diimide compound precursor of general formula (n) used is 0.1
If it is less than 100% by weight, the effect may not be sufficiently observed, and if it exceeds 100% by weight, problems such as poor applicability to the substrate tend to occur.

Solvents are used in the preparation of the composition of the present invention, but these solvents are particularly limited as long as they can dissolve the polyimide resin precursor of formula (1) and the diimide compound precursor of general formula (II). There isn't.

Specific examples of these solvents include N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylphosphoramide, and Butylthalaton and the like can be mentioned.

These may be used alone or in combination.

Furthermore, even if a solvent cannot produce a homogeneous solution by itself,
The solvent may be used in addition to the above-mentioned solvent within the range where a homogeneous solution can be obtained.

The amount of the solvent used may be within a range that uniformly dissolves the polyimide resin precursor of the -1'ff1 formula (+3) and the diimide compound precursor of the general formula (n); 0.5 to 100% per 1 part by weight of the total amount of the polyimide resin precursor and diimide compound precursor in 1)
Parts by weight are used.

The composition of the present invention can be prepared by (1) simultaneously dissolving the polyimide resin precursor of the general formula (1) and the diimide compound precursor, (2) dissolving the polyimide resin precursor of the -11Q formula (+) in a solvent. (3) A method of dissolving the diimide compound precursor in a solvent, then adding and dissolving the polyimide resin precursor of the -i formula [I], (4) ) - Single formula (a method in which the polyimide resin precursor of formula (H) and the diimide compound precursor are separately dissolved in a solvent and then mixed; (5) - the diimide compound precursor after producing the polyimide resin precursor of formula (1); Examples include a method of adding a solution thereof dissolved in a solvent, etc.

The composition of the present invention can be used as an alignment treatment agent for liquid crystal cells, and examples of the method include the following methods.

That is, after uniformly coating the composition of the present invention on a transparent substrate such as glass or plastic film with a transparent electrode by a spin code method or a printing method,
℃, preferably 150 to 250℃ for 1 minute to 2 hours to form a polyimide resin film with a film thickness of 200 to 3,000 layers, and then rub the polyimide resin m layer to obtain an alignment treatment agent for liquid crystal cells. can.

(E) Effects of the Invention The composition of the present invention can be used as an alignment treatment agent for liquid crystal cells that has a large liquid crystal tilt orientation angle and excellent uniform coating properties.

Further, the liquid crystal tilt orientation angle can be arbitrarily adjusted by changing the amount of the diimide compound precursor of the -m formula (If).

(f) Examples The present invention will be explained below with reference to Examples, but the present invention is not limited thereto.

Example 1 4.82 g (0.02 mol) of n-hexadecylamine was mixed with N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP).

) Add to 150a+42 and stir to make a homogeneous solution, then add 1
, 1.96 g (0.01 mol) of 2,3,4-cyclobutanetetracarboxylic dianhydride was added, and stirring was continued at 20°C for 4 hours.

This solution was poured into a large amount of water, and the precipitated white precipitate was filtered out and dried under reduced pressure at 30°C for 8 hours to prepare a diimide compound precursor having an alkyl chain having 16 carbon atoms.

Next, 4.1 g (0.01 mol) of 2,2-bis(4-(4-aminophenoxy)phenyl]propane and 1.92 g (0.0098 mol) of cyclobutanetetracarboxylic dianhydride were mixed with N- A polyimide resin precursor solution was prepared by reacting in 54.2 g of methylpyrrolidone at 23°C for 4 hours.

The reduced viscosity η, 2/C of the obtained polyimide resin precursor was 0.71 di/g (0.5% by weight N-methylpyrrolidone solution, 30°C).

70 g of N-methylpyrrolidone was added to 30 g of this polyimide resin precursor solution, and 0.0 g of the diimide compound precursor was added.
9g (aft amount% based on polyimide resin precursor component)
) and stirred thoroughly to form a homogeneous solution. This diluted solution was spin-coded onto two glass substrates with transparent electrodes.

No repellency was observed in the transparent electrode part, the glass substrate part, or the boundary between the two parts, and uniform coating could be performed.

Next, heat treatment was performed at 170° C. for 60 minutes to form a polyimide resin film.

After rubbing this polyimide resin film with a cloth, the rubbing direction was made parallel with a 50μ spacer in between, and the liquid crystal (
A homogeneously aligned liquid crystal cell was prepared by injecting ZLI-2293 (manufactured by Merck & Co., Ltd.).

When this liquid crystal cell was rotated in a crossed nicol environment, clear brightness and darkness were observed, confirming that it was well aligned in the rubbing direction.

Further, when the liquid crystal tilt orientation angle of this liquid crystal cell was measured using a magnetic field capacitance method, it was found to be 15°.

Comparative Example 1 A liquid crystal cell was produced in the same manner as in Example 1 using only the polyimide precursor solution shown in Example 1 without using the diimide compound precursor. When the liquid crystal tilt orientation angle of this liquid crystal cell was measured by a magnetic field capacitance method, it was found to be as low as 2.7°.

Claims (1)

[Claims] General formula [I] ▲ Numerical formulas, chemical formulas, tables, etc.▼ [I] (In the formula, R_1 is an organic group constituting a tetracarboxylic acid or its derivative, R_2 is a divalent group constituting a diamine. ) Polyimide resin precursor having a repeating unit represented by the general formula [II] ▲ Numerical formula, chemical formula, table, etc. ▼ [II] The constituent organic groups R_4 and R_5 represent organic groups constituting a monoamine having an alkyl group having 6 to 20 carbon atoms.) A composition for a liquid crystal aligning agent comprising a diimide compound precursor represented by: