JPH04186320A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To form a film free from coloration at a relatively low temperature in a short time and suppress the influence applied to a substrate, color filter, transparent electrode, etc. and improve reliability by using the polyamide resin having specific repetitive units for the orientation control film. CONSTITUTION:The orientation control film of a liquid crystal element is constituted of the polyamide resin having the repetitive unit shown by the formula I. In the formula I, R' is a bivalent residual group which is the result of removing the amino group from diamine. R<2> is the straight chained or branched chained alkyl group having the number of carbon atoms of 1 - 30. This polyamide polymer can not be dissolved in liquid crystal and water, and this polymer is dissolved into a specific solvent, and applied on a substrate, and after heating drying, the orientation control film is obtained after rubbing. Accordingly, coloration is prevented, and the film having a high strength can be prepared at a relatively low temperature in a short time, and no influence is given to the substrate, color filter, transparent electric conductive film, etc., and the superior contrast and visual characteristic can be obtained without reducing yield, and the liquid crystal display element having the reliability for a long period free from the generation of the orientation disorder even after the heat treatment for a long period can be obtained.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a liquid crystal display element.

(Prior art) Conventionally, as a liquid crystal display element that utilizes the electro-optical properties of liquid crystal, there has been a Da-type liquid crystal display element that uses a nematic liquid crystal with dielectric anisotropy and utilizes a dynamic scattering effect by applying an electric field. was being used. However, recently it has been replaced by twisted nematic (TN) liquid crystal display elements, which have liquid crystal molecules oriented in a spiral structure (Japanese Patent Publication No. 51-13666
Publication No.). As a method for producing an alignment control film for this purpose.

A method in which a thin film made of an inorganic compound such as silicon dioxide is obliquely deposited on a substrate, or a film of a surfactant or organic polymer is formed on the substrate and then rubbed (rubbed in a certain direction with a felt cloth, etc.). method is known.

(Problem to be solved by the invention) However, the method of obliquely vapor depositing silicon dioxide, etc. is difficult to apply a stable orientation control film over a large area, and is not suitable for mass production in terms of cost. Orientation control H (%Kokai No. 51-65960) was #
Although a highly reliable liquid crystal display element that is insoluble in the resin and has high heat resistance can be obtained, the display quality deteriorates because the resin itself is yellowish brown. Furthermore, since heat treatment is required at 300° C. or higher for 30 minutes or longer to complete the ring-closing condensation of the imide ring, there are problems such as deformation of the substrate, discoloration of the color filter, and increase in the resistance value of the transparent conductive film. In order to solve these problems, a liquid crystal display element (Japanese Patent Application Laid-Open No. 63-205640) using a ring-closed type aliphatic polyimide resin has been devised. This liquid crystal display element has a heat treatment temperature of 200
Although the film has a low hardness and is excellent in transparency, it has the disadvantage that it is scratched by rubbing and reduces the yield.

Therefore, the present invention solves the above-mentioned problems, and provides an alignment control film that is free from coloration, can be formed at a relatively low temperature in a short time, and does not affect substrates, color filters, transparent electrodes, etc. To provide a liquid crystal display element with high long-term reliability, which has excellent contrast and visual characteristics, which does not cause a decrease in yield, and which does not cause alignment disturbance even after long-term heat treatment tests.

(Measures to Solve the Problems) The present invention provides an alignment control film for a liquid crystal display element having the general formula (D (wherein R' represents a divalent residue of diamine excluding the amino group); The present invention relates to a liquid crystal display element which is a polyamide resin having a repeating unit represented by R'' represents a linear or branched alkyl group having 1 to 30 carbon atoms.

The polyamide polymer in the present invention is insoluble in liquid crystals and water, and this polymer is dissolved in a specific solvent and coated on a transparent conductive film such as indium oxide substrate.
After drying by heating at 0 to 200°C, an alignment control film can be obtained by rubbing. A liquid crystal display element having satisfactory characteristics can be completed by arranging the alignment control films of the two substrates thus produced in parallel and facing each other, and filling the liquid crystal between them.

The liquid crystal display element of the present invention generally has good alignment of the liquid crystal and a high refractive index of the film, so that the pattern of the transparent conductive film is less likely to be visible even when the light is not lit (nesa visibility). Since there is almost no coloring, a bright element with good contrast can be completed.

In the present invention, after coating a specific polyamide polymer on a substrate, the solvent is simply evaporated and dried.

Compared to oblique evaporation methods, etc., since it only requires a rubbing process,
An alignment control film can be obtained in a short time. for example.

The film thickness to be formed is 100 to 30,000 AJ, preferably 2
Because it is a very thin film at about 0.00 to 2000 °C, it can be sufficiently dried even below the boiling point of the solvent, and compared to the method of forming a polyimide film, it takes about 5 to 30 minutes at 100 to 200 °C
Films can be formed at low temperatures and in a short time.

As the substrate, a glass plate, polyether sulfone,
A transparent conductive film formed by vapor-depositing an association made of indium oxide and tin oxide on a film made of polysulfone, polyethylene terephthalate, etc. can be used.

The polyamide polymer used in the present invention is:

General formula (flu) as a carboxylic acid component (however, R8
is the same meaning as in general formula (I)), or this dino-1ride or diester and the general formula surface H2N-R''-NH2 ((2) (However, R' is the general formula ( It can be produced by polycondensation with the diamine represented by (same meaning as in I).

The number of carbon atoms in the straight branched alkyl group in general formula (I) is 1 to 30, preferably 1 to 10. When it exceeds 30, heat resistance decreases. The alkyl group includes 2, for example, a methyl group, an ethyl group,
n-propyl group, isopropyl group, n-butyl group, 5e
e-butyl group, fert-butyl pentyl group, impentyl group, hexful group, heptyl group, octyl group,
Examples include 2-ethyl-hexyl group, nonyl group, decyl group, dodecyl group, octadecyl group, eicosyl group, tocosyl group, triquaco/tyl group, and the like.

As the dicarboxylic acid represented by the above general formula (Il).

Examples include 5-hydroxyisophthalic acid hexanoate, 5-hydroxyisophthalic acid dodecanoate, and 5-hydroxyisophthalic acid octadecanoate.

These dicarboxylic acids represented by general formula (I) are:

For example, it can be easily obtained by reacting 5-hydroxyphyiso7tallic acid toalkylic acid chloride in the presence of pyridine or the like. The dicarboxylic acid thus obtained can be converted into an acid derivative such as cybaride or diester according to a known method.

The diamino represented by the above general formula (3) is m-tolulene diamine, m-phenylene diamine.

p-phenylenediamine, 5-rioo-m-7znylenediamine, 4,4'-diaminodiphenyl ether, λ3'-dimethyl-44'-diaminodiphenyl ether, 43'-dimethoxy-4,4'-diaminodiphenyl ether, λ3'-sia ξNodiphenyl ether, 3.4'-diaminodiphenyl ether 4゜4'-
Benzidine, 4.4'-diaminodiphenylthioether, 3'-diaminodiphenylthioether, 44'
-diaminobenozophenono, 3'-diaminodiphenylmethane, 44'-diaminodiphenylmethane, z2-
Bis(3-aminophenyl)propane, 42-bis(4
-aminophenyl)furopane, 4,4'-diaminodiphenylsulfo/, 44'-diaminodiphenylsulfoxide, 3,3'-diaminodiphenylsulfono, a3'-diaminobiphenyl, 1,3-bis(4-aminophenoxy) Benzene, 1.3-bis(3-aminophenoxy)benzene, 1.4-bis(4-aminophenoxy)benzene, 4.4'-[1,3-7 22lenebis(1-methylethylidene)co, 4.4'-[1,
4-phenyne/bis(1-methylethylidene)], ]su2-bisE4-4-aminophenoxy7)phenyl]propane, 2,2-bis[3-methyl-4-(4-aminophenoxy)phenylconitane , 2.2-bis[3-
Chloro-4-(4-aminophenoxy]phenyl"propane, 1.1-bis[4-(4-aminophenoxy)phenylconitane, bis[:4-(4-amino7cnoxy)phenylcomethane, 3.3 '-dimethoxy-44
'-Diamine biphenyl, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone.

Su2-bis[4-(3-aminophenoxy)phenylcofuropane, 4.4'-bis(4-aminophenoxy)biphenyl, Su2-bis[4-(4-aminophenoxy)
Phenylcohexafluoropropane, 9,9-bis(4
Aromatic diamines such as -aminophenyl)fluorene, 1
．． 3-diaminodicyclohexane, 1,4-diaminodicyclohexane.

Examples include aliphatic cyclic diamines such as 44'-diaminocyclohexylmethane.

The polyamide resin in the present invention contains aromatic dicarboxylic acids such as terephthalic acid, inphthalic acid, 4.4'-diphenyl ether dicarbo7M+44'-'; phenylcarboxylic acid, and 1.5-naphthalene dicarboxylic acid as a carboxylic acid component. May contain.

These are preferably used in an amount of 50 mol % or less based on the total carboxylic acid components. If these amounts are too large, the solubility in organic solvents tends to decrease. Also.

As a carboxylic acid component, aliphatic dicarboxylic acids such as adipic acid and sebacic acid are used in an amount of 50 mol% based on the total carboxylic acid component.
May be used below. Too much aliphatic dicarboxylic acid tends to reduce heat resistance.

Similarly, as a diamine component, hexamethylene diamine,
Aliphatic diamines such as ethylenediamine.

Alternatively, siloxane diamines such as L3-bis(3-aminopropyl)tetramethyldisiloxane and L3-bis(4-aminophenyl)tetramethyldisiloxane may be used to improve adhesion to glass substrates and metals. However, it is preferable to use it in an amount of 30 mol % or less based on the total diamine. If there are too many of these, heat resistance tends to decrease. The above-mentioned aromatic dicarboxylic acids and aliphatic dicarboxylic acids can be used as they are or dino-
Ride young is used as a diester.

The method for polycondensing the polyamide polymer is as follows.

A low temperature polycondensation method, a direct polycondensation method, an active ester method, etc. can be employed, and there are no particular restrictions.

In the low-temperature polycondensation method, the amount of civalide of the dicarboxylic acid is preferably 0.9 to 2, for example, per equivalent of the diamino.
Use 1.2 equivalents of triethylamine.

Tertiary amines such as tripropylamine, tributylamine, triamylamine, propylene oxide.

1.2 of styrene oxide, cyclohexene oxide, etc.
-N-methyl- in the presence of an oxidation acceptor such as an epoxide
The reaction is carried out in a non-reactive polar solvent such as 2-pyrrolidone or dimethylacetamide at a temperature ranging from minus a few degrees to the reflux temperature of the organic solvent.

In the direct polymerization method, for example, the above-mentioned dicarboxylic acid and the above-mentioned diamino are used in an equivalent or almost the same amount, and a phosphorus catalyst such as triphenyl phosphite, trichloride, phosphoric acid ester, etc. and pyridine or the above-mentioned diamino are used. The reaction is carried out in a non-reactive organic solvent similar to that at a temperature ranging from room temperature to reflux temperature. In this case, the phosphorus-based catalyst is used in an equivalent or approximately equivalent amount to the dicarboxylic acid or the diamine,
It is preferable that the derivative of pyridine is used in an amount of 10 mol % or more based on the dicarboxylic acid or diamine.

In the active ester method, for example, a benzotrianol ester is produced by reacting the dicarboxylic acid civalide with 1-hydroxybenzotriazole, this ester and the diamine are used in equivalent or nearly equivalent amounts, and the same non-reacting method as described above is used. The reaction is carried out in a polar organic solvent at room temperature or higher.

The reaction solution obtained as described above is poured into a large excess of a lower alcohol such as methanol and a solvent that is compatible with the above organic solvent such as water and is a poor solvent with respect to the resin to obtain a precipitate. The polyamide resin of the present invention can be recovered by filtering this and drying it.

The above polyamide resin is applied to the liquid crystal holding substrate and the electrodes using a solvent such as dimethyl sulfoxide, dimethyl formamide, dimethyl acetamide, N-methyl-2-pyrrolidone, dimethyl imidazolidinone, cyclohexanone, etc. alone or in a mixture thereof. Alternatively, a mixture of appropriate amounts of toluene, xylene, etc., within a range capable of dissolving the polyamide, is used to prepare a solution of α1 to 40% by weight, and this is prepared using the dip method.

It can be applied onto the substrate and electrodes by a spray method, a printing method, a brush coating method, or the like.

Here, for the purpose of improving the adhesion between the substrate and the electrode, the substrate and the electrode may be pretreated using a commercially available coupling agent 2, such as a silane type or a titanate type, or added to the polyamide solution.

After coating, a polyamide resin film is obtained by drying at 100 to 300°C, but here.

A temperature of 100 to 200°C is also sufficient. A liquid crystal alignment control film can be obtained by rubbing this resin film. A liquid crystal display element can be obtained by arranging the alignment control films of the two substrates thus produced in parallel and facing each other, and filling liquid crystal between them.

(Example) Next, two examples of the present invention will be explained.

For evaluation of alignment stability, a 90° twisted cell with a gap of 6 μm was used, and ZLI-1132 (manufactured by Merck & Co., Ltd.) was used as the enclosed liquid crystal.

Example 1 285 g of 44'-diaminodiphenyl ether (14,
3mmol), 5-hydroxyisophthalic acid hexanoate 4.00g (143mmol), triphenylphosphite 8.8g (21L3mmol)
), 45 g (57.0 mmol) of pyridine, and 0.5 g (11.8 mmol) of lithium chloride in N-methyl-
It was dissolved in 40 ml of 2-pyrrolidone and reacted at 110°C, and the resulting polyamide resin was isolated. N again
The polyamide resin is isolated by dissolving it in methyl-2-pyrrolidone and pouring it into a 1:1 mixture of water and methanol, and then purifying it by boiling it with methanol. Add N-methyl-2 to 3% by weight of this polyamide resin.
- Dissolved in a 6=4 mixture of pyrrolidone and butylseron lupacetate to prepare a varnish. This varnish was uniformly applied onto a glass plate having a transparent conductive film that had been thoroughly cleaned using a spinner at 300 rpm. 200℃
This was dried for 30 minutes to form a polyamide resin film with a thickness of 700 mm. The pencil strength of the film at this time was 5H. This film was rubbed in a fixed direction with T-7 Elt to produce a glass substrate having an alignment control film. A liquid crystal display element for evaluation of alignment stability was prepared from this substrate and evaluated, and it was found to exhibit good alignment.

Example 2, 4.4'-diaminodiphenyl ether λ85g
(143 mmol) instead of 1,4-bis(4-aminophenoxy)benzene 4.17 g (14,3 mmol)
o, l) A polyamide resin was synthesized by carrying out the same operation as in Example 1, except that the whole sample was used. A glass substrate having an alignment control film was prepared from this polyamide resin in the same manner as in Example 1, and the alignment stability was evaluated, and it was found to have good alignment. Further, the lead*@ degree of this film was 5H.

Example 3'44'-diaminodiphenyl ether 2.85 g (14
, 3 mmol) instead of 4,4'-bis(4-aminophenoxy)biphenyl & 26 g (14,3 mmol)
) A polyamide resin was synthesized by carrying out the same operation as in Example 1, except for using the following. A glass substrate having an alignment control film was prepared from this polyamide resin in the same manner as in Example 1, and the alignment stability was evaluated, and it was found to have good alignment. Further, the pencil strength of this film was 5H.

Example 4 5-hydroxyinphthalic acid hexanoate 4.00 g
(14.3 mmol) instead of 5-hydroxyisophthalic acid hexanoate 5.21 g (14.3 mmol)
) Synthesis was carried out on a polyamide resin in the same manner as in Example 1 except that the whole sample was used. A glass substrate with an orientation control of 1K was prepared from this polyamide resin in the same manner as in Example 1, and when the orientation stability was evaluated, it was found to have good orientation. Further, the pencil strength of this film was 5H.

Example 5 4.4'-diaminodiphenyl ether 185g (14
A polyamide resin was synthesized in the same manner as in Example 4, except that 4.17 g (14.3 mmol) of 1,4-bis(4-aminophenoxy)benzea was used instead of 1.4-bis(4-aminophenoxy)benzea. A glass substrate having an alignment control film was prepared from this polyamide resin in the same manner as in Example 1, and the alignment stability was evaluated.

It showed good orientation. In addition, the pencil strength of this film is 5H.
Met.

Example 6 2.85 g of 44'-diaminodiphenyl ether (14
44'-bis(4-aminophenoxy)biphenyl 5.26 g (14.3 mmol) instead of 44'-bis(4-aminophenoxy)biphenyl
) The same procedure as in Example 1 was carried out to sweeten the polyamide resin, except that the entire stool was used. A glass substrate for forming an orientation control film was prepared from this polyamide resin in the same manner as in Example 1, and the orientation stability was evaluated, and it was found that the substrate had good orientation. In addition, the pencil strength of this film is 5H, which is 9.

Example 7 5-hydroxyisophthalic acid hexanoate 4.00
g (143 mmol) instead of 41 g (143 mmol) of 5-hydroxyhiso7talate octadecanoate a.
l) A polyamide resin was synthesized in the same manner as in Example 1, except that 1 was used. A glass substrate having an alignment control film was prepared from this polyamide resin in the same manner as in Example 1, and the alignment stability was evaluated, and it was found to have good alignment. Also.

The pencil strength of this film was measured at 5H.

Example 8 285 g of 44'-diaminodiphenyl ether (14,
A polyamide resin was synthesized by performing the same operation as in Example 7 except for using 4.17 g (14.3 mmol) of 1,4-bis(4-aminophenoxy)benzene instead of 3 mmol). A glass substrate having an alignment control film was prepared from this polyamide resin in the same manner as in Example 1, and the alignment stability was evaluated, and it was found to have good alignment. In addition, the pencil strength of this film is 5H.

Example 9 44'-') 7mi/diphenyl ether 185g (14
A polyamide resin was synthesized in the same manner as in Example 1, except that 5.26 g (143 mmol) of 4,4'-bis(4-aminophenoxy)biphenyl was used instead of 3 mmol). A glass substrate with orientation control W& was produced from this polyamide resin in the same manner as in Example 1,
Evaluation of orientation stability showed good orientation. Also, the pencil strength of this film was 5H.

Comparative Example 1 369 g (0
,9 mol), 1,3-bis(3-7minoprobyl)tetramethyldi/loxane 24.8 g (0.1 mol)
) and N-methyl-2-pyrrolitono (NMP) 1843
Add 396 g of bis(exo-bicyclo[λ2,1 cohebutane-43-dicarboxylic anhydride) sulfoyl(exo-bicyclo[λ2,1 cohebutane-43-dicarboxylic anhydride)
1.0 mol) was added. The reaction was carried out at room temperature for 4 hours to synthesize polyamic acid, and then the temperature was raised to 180°C.
A ring-closing dehydration reaction was carried out at 205°C for 4 hours and at 205°C for 2 hours. The obtained reaction solution was poured into a large amount of methanol, and the precipitate was filtered off and dried under reduced pressure to obtain a polyimide polymer. Reduced viscosity (IP/C) of this polymer (dimethylformamide 0
．． 2% by weight solution, measured at 30°C) is 0.97d(/g
Met. In addition, the glass transition temperature (Tg) of this polymer
The temperature was measured at 295°C. This polymer was mixed with N-methyl-2-pyrrolidone 9. From the thus obtained varnish, a glass substrate on which an alignment control film tV was to be applied was prepared in the same manner as in Example 1, and the alignment stability was evaluated, and good alignment was shown. Ta. However, the pencil strength of this film was as low as H. (Effects of the Invention) According to the present invention, by using a polyamide polymer for the alignment control film, there is no discoloration and the temperature is relatively low.

F5 plate is used to ensure that a high-quality film can be formed in a short period of time.

It does not cast a shadow on color filters, transparent conductive films, etc., has excellent contrast and visual characteristics without reducing retention, and has a long delivery life without causing orientation disturbance even after long-term heat treatment tests. A highly reliable liquid crystal display element can be obtained.

Agent Patent Attorney Kunihiko Wakabayashi

Claims (1)

[Claims] 1. The alignment control film of a liquid crystal display element has the general formula (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (I) (However, in the formula, R^1 excludes the amino group of diamine. Ta2
A liquid crystal display element which is a polyamide resin having repeating units represented by (representing a valent residue and R^2 represents a linear or branched alkyl group having 1 to 30 carbon atoms).