JPH0625835B2 - Composition for liquid crystal 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 of the polyimide precursor and the monoamine having a long-chain alkyl group that constitute the above composition is not always sufficient, and may cause problems in uniform coating properties when applied on a substrate as a liquid crystal alignment treatment agent. However, considering industrial production, it was not always satisfactory.

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.) And a polyimide resin precursor having a repeating unit represented by the general formula [ II) (In the formula, R ₃ represents an organic group constituting a tetracarboxylic acid or a derivative thereof, and R ₄ and R ₅ represent an organic group constituting a monoamine having an alkyl group having 6 to 20 carbon atoms.) The present invention relates to a composition for a liquid crystal alignment treatment agent containing a compound precursor.

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 reacted with a diamine of the general formula [IV] in a polar solvent such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone. It is common to let 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, and 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 has the general formula [V] (In the formula, R ₃ represents a tetravalent organic group constituting tetracarboxylic acid, and the four carbonyl groups bonded to R ₃ are directly bonded to different carbon atoms.) Tetra One or more compounds selected from carboxylic acids and their derivatives and the general formulas [VI] and [VII] R ₄ —NH ₂ [VI] R ₅ —NH ₂ [VII] (wherein R ₄ , R ₅ represents an organic group constituting a monoamine having an alkyl group having 6 to 20 carbon atoms.).

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, a dicarboxylic acid dianhydride is used as the tetracarboxylic acid of the general formula [V] and its derivative, and the compound of the general formula [VI] and [VII] is used in a polar solvent such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone. It is common to carry out the reaction so that the molar ratio of the monoamine to the tetracarboxylic dianhydride 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 generated diimide compound precursor solution may be used as it is,
Also, throw in a large excess of water or a poor solvent such as methanol,
The diimide compound precursor may be recovered by precipitation and used.

The tetracarboxylic acids of the general formulas [III] and [V] and their derivatives may be the same or different from each other.

Specific examples thereof include aromatic tetracarboxylic acids such as pyromellitic acid, benzophenonetetracarboxylic acid, and 3,4,3 ′, 4′-biphenyltetracarboxylic acid, dianhydrides thereof, and dicarboxylic acid diacid halogens thereof. Compounds, alicyclic tetracarboxylic acids such as cyclobutanetetracarboxylic acid, cyclopentanetetracarboxylic acid and cyclohexanetetracarboxylic acid, and dianhydrides thereof, and dicarboxylic acid diacid halides thereof and aliphatic tetracarboxylic acids such as butanetetracarboxylic acid. Examples thereof include carboxylic acids, dianhydrides thereof, and dicarboxylic acid diacid halides thereof.

The tetracarboxylic acids represented by the general formulas [III] and [V] and their derivatives may be used alone or in combination of two or more.

Specific examples of the diamine of the general formula [IV] include p-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) 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- (4-aminophenoxy) phenyl]
Aromatic diamines such as propane And other diaminosiloxanes.

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} general formula [VI] monoamine of the general formula [VII]
May be the same or different from each other.

Specific examples thereof include n-hexylamine, n-octylamine, n-decylamine, n-dodecylamine, n.
-Hexadecylamine, 1,3-dimethylbutylamine,
Aliphatic amines such as 1,5-dimethylhexylamine and 2-ethylhexylamine, p-aminophenylhexane, p-aminophenyloctane, p-aminophenyldodecane, p-aminophenylhexadecane, p-aminophenoxyoctane, p- Aromatic amines such as aminophenoxydodecane and p-aminophenoxyhexadecane can be mentioned.

These monoamines may be used alone or in admixture of two or more.

When the carbon number of R ₄ and R ₅ which are alkyl groups of the monoamine of the general formula [II] is 5 or less, the effect of increasing the tilt alignment angle of liquid crystal molecules is not sufficient.

Further, if the carbon number of R ₄ and R ₅ exceeds 20, problems such as deterioration in coating property on the substrate are likely to occur.

The amount of the diimide compound precursor of the general formula [II] used is [I]
It is usually used in an amount of 0.1 to 100% by weight based on the polyimide resin precursor.

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.

Solvents are used in the preparation of 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]. Absent.

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, and generally the general formula [I] 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.

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,
Dissolving method, (3) after dissolving the diimide compound precursor in a solvent, a method of adding and dissolving the polyimide resin precursor of the general formula [I], (4) polyimide resin precursor and diimide of the general formula [I] A method in which the compound precursors are separately dissolved in a solvent and then mixed, (5) a method for adding a diimide compound precursor after manufacturing the polyimide resin precursor of the general formula [I], or a solution thereof dissolved in a solvent is used. Can be mentioned.

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 4.82 g (0.02 mol) of n-hexadecylamine was added to N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP).
After adding to 150 ml and stirring to make a uniform solution, 1,2,3,4-
Cyclobutane tetracarboxylic acid dianhydride 1.96 g
(0.01 mol) was added and stirring was continued for 4 hours at 20 ° C.

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, 2,2-bis [4- (4-aminophenoxy) phenyl]
Propane 4.1 g (0.01 mol) and cyclobutane tetracarboxylic acid dianhydride 1.92 g (0.0098 mol) were reacted in 54.2 g of N-methylpyrrolidone at 23 ° C. for 4 hours to give a polyimide resin precursor solution. It was adjusted.

Reduced viscosity ηsp / C0.7 of the obtained polyimide resin precursor
1 dl / g (0.5% by weight, N-methylpyrrolidone solution, 30
℃).

To 30 g of this polyimide resin precursor solution, 70 g of N-methylpyrrolidone was added, and the diimide compound precursor 0.09 was added.
g (3% by weight with respect to the polyimide resin precursor component) was added and sufficiently stirred to obtain a uniform solution. 2 this diluted solution
A glass substrate with a transparent electrode was spin-coated.

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 was measured by the magnetic field capacitance method and found to be 15 °.

Comparative Example 1 A liquid crystal cell was produced 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. When the liquid crystal tilt alignment angle of this liquid crystal cell was measured by the magnetic field capacitance method, it was as low as 2.7 °.

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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 the following formula: [II] (In the formula, R ₃ represents an organic group constituting a tetracarboxylic acid or a derivative thereof, and R ₄ and R ₅ represent an organic group constituting a monoamine having an alkyl group having 6 to 20 carbon atoms.) One or more compounds selected from acids and their derivatives, and 1 to 6 carbon atoms
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 monoamines.