JPH0625834B2 - Composition for liquid crystal cell alignment treatment agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a composition for liquid crystal alignment treatment 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 tilt alignment angle with respect to a substrate and which is excellent in uniform coating property.

(B) Conventional technology As a substrate treating agent for orienting nematic liquid crystal molecules substantially parallel to a transparent substrate such as glass or a plastic film having a transparent electrode, organic resin films such as polyimide resin film have been conventionally used. Most commonly used.

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

Further, as a method of largely orienting liquid crystal molecules, a method of depositing an inorganic film such as silicon oxide on a substrate has been conventionally performed.

(C) Problems to be Solved by the Invention In the conventional method of rubbing the organic resin film formed on the substrate, it is difficult to align the liquid crystal molecules to a large tilt.

Further, the method of depositing an inorganic film on a substrate is more complicated than the rubbing method, and is not necessarily an appropriate method in actual industrial production.

(D) Means for Solving the Problems As means for solving the above problems, JP-A-62-262
No. 829 proposes using a composition comprising a polyimide resin precursor and a monoamine having a long-chain alkyl group as a liquid crystal alignment treatment agent.

According to this method, the tilt alignment angle of the liquid crystal can be increased by the rubbing treatment.

However, the compatibility between the polyimide precursor and the monoamine having a long-chain alkyl group and the compatibility thereof are not always sufficient, and may cause a problem in uniform coatability when applied on a substrate as a liquid crystal alignment treatment agent. However, it was not always satisfactory when industrial production was taken into consideration.

The present inventors have completed the present invention as a result of earnestly studying to solve the above problems.

That is, the present invention has the general formula [I] (In the formula, R ₁ represents an organic group constituting a tetracarboxylic acid or a derivative thereof, and R ₂ represents a divalent organic group constituting a diamine.) A polyimide resin precursor having a repeating unit represented by Formula [II] (In the formula, R ₃ represents a divalent organic group which constitutes diamine,
₄ and R ₅ each represent an organic group constituting a dicarboxylic acid having a C 6 to C 20 alkyl group or a derivative thereof. ] It is related with the composition for liquid crystal aligning agents containing the diimide compound precursor represented by these.

The composition of the present invention is used as an alignment treatment agent for liquid crystal cells by applying it on a transparent substrate such as glass or a plastic film having a transparent electrode and curing it to form a polyimide resin film, and then subjecting it to a rubbing treatment. be able to.

The polyimide resin precursor of the general formula [I] used in the composition of the present invention has the general formula [III] (In the formula, R ₁ represents a tetravalent organic group constituting tetracarboxylic acid, and the four carbonyl groups bonded to R ₁ are directly bonded to different carbon atoms.) Tetra One or more compounds selected from carboxylic acids and their derivatives and the general formula [IV] H ₂ NR ₂ —NH ₂ [IV] (wherein R ₂ represents a divalent organic group constituting diamine) .) Is obtained by reacting a diamine represented by

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

For example, a tetracarboxylic acid dianhydride is used as the tetracarboxylic acid of the general formula [III] and its derivative, and is reacted with a diamine of the general formula [IV] in a polar solvent such as dimethylformamide, dimethylacetamide and N-methylpyridone. Is common. The molar ratio of the tetracarboxylic dianhydride and the diamine to be further reacted is 0.5 to
2, preferably 0.9 to 1.1. Like the usual polycondensation reaction, the closer the molar ratio of these two components is to 1, the larger the molecular weight of the polyimide resin precursor produced.

The reaction temperature for forming the polyimide resin precursor is −20 to 20.
It is 150 ° C, preferably -5 to 100 ° C.

The diimide compound precursor of the general formula [II] used in the composition of the present invention is represented by the general formula [V] H ₂ NR ₃ —NH ₂ [V] (wherein R ₃ is a divalent organic compound that constitutes a diamine). And a compound of the formula [VI] and a compound of the formula [VII] (Wherein R ₄ and R ₅ represent an organic group constituting a dicarboxylic acid having an alkyl group having 6 to 20 carbon atoms or a derivative thereof), and are obtained by reacting with a dicarboxylic acid represented by or a derivative thereof. To be

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

For example, as the dicarboxylic acid or a derivative thereof of the general formulas [VI] and [VII], a dicarboxylic acid anhydride is used, and in a polar solvent such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, the general formulas [VI] and [VI] are used. VI
It is common to carry out the reaction so that the ratio of the number of moles of the dicarboxylic acid anhydride represented by I] to the number of moles of the diamine of the general formula [V] is 1: 1: 1.

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

The produced diimide compound precursor solution may be used as it is, or may be used by precipitating and recovering the diimide compound precursor by throwing it in a large excess of a poor solvent such as water or methanol.

Specific examples of the general formula [III] include aromatic tetracarboxylic acids such as pyromellitic acid, benzophenonetetracarboxylic acid, 3,4,3 ', 4'-biphenyltetracarboxylic acid, and their dianhydrides and their dianhydrides. Dicarboxylic acid diacid halide, cyclobutanetetracarboxylic acid, cyclopentanetetracarboxylic acid, alicyclic tetracarboxylic acid such as cyclohexanetetracarboxylic acid and dianhydrides thereof, and dicarboxylic acid diacid halide and butanetetracarboxylic acid And aliphatic carboxylic acids, dianhydrides thereof, dicarboxylic acid diacid halides thereof, and the like.

The tetracarboxylic acid of the general formula [III] and its derivative may be used alone or in combination of two or more.

The diamines represented by the general formulas [IV] and [V] may be the same or different from each other.

Specific examples thereof include p-phenylenediamine, m-phenylenediamine, diaminodiphenylmethane, diaminophenyl ether, 2,2-diaminodiphenylpropane, diaminodiphenylsulfone, diaminobenzophenone, diaminonaphthalene, 1,3-bis (4-amino). Phenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 4,4'-di (4-aminophenoxy) diphenyl sulfone, 2,2'-bis [4- (4-aminophenoxy) phenyl] propane , 1,1,1,3,3,3-hexafluoro-2,2-bis [4-aminophenyl] propane, 1,1,1,3,3,3-hexafluoro-2,2-bis [ 4-
Aromatic diamine such as (4-aminophenoxy) phenyl] propane, Can be given.

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

Further, one kind or a mixture of two or more kinds of these diamines can be used.

R ₄ and R ₅ of the dicarboxylic acid of the general formula [VI] or the general formula [VII] or a derivative thereof may be the same or different from each other.

Specific examples thereof include n-hexyl succinic acid, n-octyl succinic acid, n-dodecyl succinic acid, n-tetradecyl succinic acid, n-hexadecyl succinic acid, n-dodecyl glutaric acid, n-hexadecyl glutaric acid. , N-octylphthalic acid, n-dodecylphthalic acid, n-hexadecylphthalic acid, 3-hexadecyloxyphthalic acid, 3-dodecyloxycarbonylphthalic acid, 3-tetradecyloxycarbonylphthalic acid, 3-hexadecyloxy Carbonyl phthalic acid, n-octyl hexahydrophthalic acid, n
-Dodecylhexahydrophthalic acid or a derivative thereof and the like can be mentioned, but the invention is not limited thereto.

The above dicarboxylic acids or their derivatives can be used alone or in admixture of two or more.

When the carbon number of the alkyl group contained in this dicarboxylic acid or its derivative is 5 or less, the effect of increasing the tilt alignment angle of the liquid crystal molecules is not sufficient.

Further, if the number of carbon atoms of the alkyl group exceeds 20, problems such as poor coatability on the substrate are likely to occur.

The amount of the diimide compound precursor of the general formula [II] used is usually 0.1 to 1 with respect to the polyimide resin precursor of the general formula [I].
It is used in an amount of 00% by weight.

The amount of the diimide compound precursor of the general formula [II] 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, inconvenience such as deterioration of coating property on the substrate is likely to occur.

A solvent is used to prepare the composition of the present invention.

These solvents are not particularly limited as long as they dissolve the polyimide resin precursor of the general formula [I] and the diimide compound precursor of the general formula [II].

Specific examples of these solvents include N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone,
Hexamethylphosphoramide, butyl taraton and the like can be mentioned.

These may be used alone or in combination.

Furthermore, even if the solvent alone does not provide a uniform solution,
You may use the solvent in addition to the said solvent within the range which can obtain a homogeneous solution.

Further, the amount of the solvent used may be within a range in which the polyimide resin precursor of the general formula [I] and the diimide compound precursor of the general formula [II] are uniformly dissolved. 0.5 to 100 parts by weight is used for 1 part by weight of the total amount of the polyimide resin precursor and the diimide compound precursor of I].

The method for preparing the composition of the present invention includes (1) a method of simultaneously dissolving a polyimide resin precursor of general formula [I] and a diimide compound precursor, and (2) a polyimide resin precursor of general formula [I] in a solvent. After dissolution, add diimide compound precursor,
Method of dissolving, (3) a method of adding and dissolving a polyimide resin precursor of general formula [I] after dissolving the diimide compound precursor, (4) polyimide resin precursor and diimide compound precursor of general formula [I] A method in which the bodies are separately dissolved in a solvent and then mixed.

(5) A method in which the polyimide resin precursor of the general formula [I] is manufactured and then the oligomer precursor or a solution thereof dissolved in a solvent is added.

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

That is, the composition of the present invention is applied uniformly on a transparent substrate such as glass or plastic film having a transparent electrode by a spin coating method or a printing method, and then 100-400.
C., preferably 150 to 250.degree. C., and cured for 1 minute to 2 hours to form a polyimide resin film having a film thickness of 200 to 3000.degree.

(E) Effect of the Invention The composition of the present invention can be used as an alignment treatment agent for liquid crystal cells, which has a large liquid crystal tilt alignment angle and is excellent in uniform coating property.

Further, the liquid crystal tilt alignment angle can be arbitrarily adjusted by changing the amount of the diimide compound precursor of the general formula [II] used.

(F) Examples Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto.

Example 1 4.1 g ((0.01 mol)) of 2,2-bis [4- (4-aminophenoxy) phenyl] propane was added to 20 g of N-methylpyrrolidone.
After adding to 0 ml and stirring to make a uniform solution, 6.48 g (0.02 mol) of n-hexadecyl succinic anhydride was added and stirring was continued at 20 ° C. for 4 hours.

This solution was poured into a large amount of water, the white precipitate thus deposited was filtered, and then 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.
Was reacted in 54.2 g of N-methylpyrrolidone at 23 ° C. for 4 hours to prepare a polyimide resin precursor solution. The reduced viscosity ηsp / C of the obtained polyimide resin precursor is 0.71 dl / g.
(0.5% by weight, N-methylpyrrolidone solution, 30 ° C.).

To 30 g of this polyimide resin precursor solution, 70 g of N-methylpyrrolidone and 0.3 g of the diimide compound (10% by weight based on the polyimide resin precursor component) were added, and sufficiently stirred to obtain a uniform solution.

This diluted solution was spin-coated on two glass substrates with transparent electrodes.

No cissing was observed on the transparent electrode portion, the glass substrate portion and the boundary portion between the two portions, and uniform coating could be performed.

Then, 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, assemble it with rubbing directions parallel to each other with a 50μ spacer in between.
A liquid crystal cell (manufactured by Merck: ZLI-2293) was injected to prepare a homogeneously aligned liquid crystal cell.

When this liquid crystal cell was rotated in crossed Nicols, clear light and dark were seen, and it was confirmed that the liquid crystal cell was favorably aligned in the rubbing direction.

The liquid crystal tilt alignment angle of this liquid crystal cell measured by the magnetic field capacitance method was 19 °.

Example 2 2.48 g (0.01 mol) of N-methylpyrrolidone 8.
After adding to 06 g and stirring to make a uniform solution, 6.48 g (0.02 mol) of n-hexadecyl succinic anhydride was added and stirring was continued at 20 ° C. for 4 hours to prepare a diimide compound precursor solution.

Next, a polyimide precursor was prepared in the same manner as in Example 1,
The diimide compound precursor 2.4 was added to 30 g of this solution.
g and 67.6 g of N-methylpyrrolidone were added and sufficiently stirred to form a uniform solution.

This diluted solution was spin-coated on two glass substrates with transparent electrodes. No cissing was observed on the transparent electrode portion, the glass substrate portion, and the boundary portion between the two portions in this test product, and uniform coating could be performed. After that, a liquid crystal cell was prepared in the same manner as in Example 1 and the liquid crystal tilt alignment angle was measured by the magnetic field capacitance method and found to be 12 °.

Comparative Example 1 A liquid crystal cell was prepared in the same manner as in Example 1, except that the polyimide precursor solution shown in Example 1 was used without using the diimide compound precursor.

The tilt orientation angle of this liquid crystal cell was measured.
It was as low as 7 °.

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Claims (1)

[Claims] 1. A general formula [I] (In the formula, R ₁ represents an organic group constituting a tetracarboxylic acid or a derivative thereof, and R ₂ represents a divalent organic group constituting a diamine.) A polyimide resin precursor having a repeating unit represented by Formula [II] (In the formula, R ₃ is a divalent organic group R ₄ constituting diamine,
R ₅ represents an organic group constituting a dicarboxylic acid having a C 6-20 alkyl group or a derivative thereof. ) One or more diamines represented by
A composition for a liquid crystal alignment treatment agent, which comprises a diimide compound precursor which is a compound obtained by reacting one or two kinds of dicarboxylic acids having 0 alkyl groups or derivatives thereof.