JP2002131751A - Composition for liquid crystal aligning film, liquid crystal aligning film, liquid crystal holding substrate, liquid crystal display and horizontal electric field liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for a liquid crystal aligning film which ensures good aligning function independently of rubbing conditions, a liquid crystal aligning film using the composition and giving an image of high image quality, liquid crystal holding substrates, a liquid crystal display and a horizontal electric field liquid crystal display. SOLUTION: The composition contains a polyimide having repeating units of formula (I) (where W is a tetravalent organic group and R is a divalent organic group) or its precursor. At least part of the repeating units have a specified divalent organic group as the symbol R. The liquid crystal aligning film is obtained by rubbing a polyimide film formed from the composition. Each of the liquid crystal holding substrates has the liquid crystal aligning film. Each of the liquid crystal display and the horizontal electric field liquid crystal display has the liquid crystal holding substrates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a composition for a liquid crystal alignment film for controlling the alignment of a liquid crystal, a liquid crystal alignment film, a liquid crystal sandwiching substrate,
The present invention relates to a liquid crystal display and a lateral electric field liquid crystal display.

[0002]

2. Description of the Related Art A conventional liquid crystal display device employs a display system typified by a twisted nematic display system by using a transparent electrode made of ITO (indium tin oxide) or the like for each opposing substrate. . A liquid crystal alignment film is provided on the transparent electrode, and a polyimide-based liquid crystal alignment film (see JP-A-55-10180, JP-A-63-259515, etc.) is used. These are obtained by drying and dehydrating and ring-closing the material applied on the substrate in the range of 180 to 350 ° C. to form a polyimide film, and performing a rubbing treatment.

[0003] Liquid crystal displays (LCDs) are widely used as thin and low power consumption displays, the main one of which is the twisted nematic system (TN system) using nematic liquid crystal. No. As means for solving this problem, an in-plane switching method (IP) in which a comb-shaped electrode is provided on one substrate and a display is driven by applying a horizontal electric field parallel to the substrate.
S type) liquid crystal display device (see Japanese Patent Application Laid-Open No. 6-160878)
Has been proposed. In order for these liquid crystal display devices to become more general-purpose, it is required to display images of higher quality.

In the IPS method, rubbing is not sufficiently performed due to the influence of the step between the comb-teeth electrode and the thin film transistor (TFT), and an alignment defect may occur at that portion. The liquid crystal alignment film material shown has been eagerly desired. In addition, a photo-liquid crystal alignment film material using ultraviolet light, laser light or the like (for example, M. Schadt et al., Japanese Journal
nal of Applied Physics, 31, P.2155 (1992), JP-A-5-34
699, JP-A-6-281937, JP-A-11-14995, etc.) have also been proposed, but when ultraviolet light or laser light is used, the deterioration of the film surface progresses and the voltage holding ratio decreases. And problems such as deterioration of the afterimage characteristics occur. Therefore, it is difficult to put the photo-liquid crystal alignment film material into practical use.

An object of the present invention is to solve the drawbacks of the prior art and to provide a composition for a liquid crystal alignment film capable of obtaining a good alignment function regardless of rubbing conditions. Further, a second object of the present invention is to provide a liquid crystal alignment film, a liquid crystal holding substrate, a liquid crystal holding device, and a horizontal electric field liquid crystal display device which use the composition for a liquid crystal alignment film and show a high-quality image.

[0006]

The present invention provides a compound represented by the general formula (I):

Embedded image (Wherein, W has a tetravalent organic group and R represents a divalent organic group), and at least a part of the total number of the repeating units is represented by the general formula (II)

Embedded image Or general formula (III)

Embedded image(Where R¹, R^Two, R^ThreeAnd R^FourAre independent of each other
Child or-(CH_Two)_n-CH _ThreeAnd n is an integer of 0 to 7
A) a polyimide having a divalent organic group represented by
A composition for a liquid crystal alignment film comprising the precursor
You.

The present invention also relates to the liquid crystal alignment film, wherein at least 50 mol% of the total number of the repeating units has a diamine residue represented by the general formula (II) or (III) as R. Composition. The present invention also relates to the composition for a liquid crystal alignment film, wherein at least a part of the total number of the repeating units has an oxydiphthalic dianhydride residue as a tetravalent organic group represented by W. The present invention also relates to the composition for a liquid crystal alignment film, wherein at least 30 mol% of the total number of the repeating units has an oxydiphthalic dianhydride residue as W.

The present invention also relates to a liquid crystal alignment film obtained by rubbing a polyimide film formed from any one of the above-mentioned compositions for a liquid crystal alignment film. The present invention also relates to the liquid crystal alignment film having a pretilt angle of 2 degrees or less.

Further, the present invention relates to a liquid crystal sandwiching substrate having the above-mentioned liquid crystal alignment film. Further, the present invention relates to a liquid crystal display device having the liquid crystal sandwiching substrate. Further, the present invention relates to a horizontal electric field liquid crystal display device having the liquid crystal sandwiching substrate.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The composition for a liquid crystal alignment film of the present invention comprises:
It contains a polyimide having a repeating unit represented by the general formula (I) or a precursor thereof. Here, the polyimide precursor refers to a material that can be closed to form a polyimide having the repeating unit represented by the general formula (I), and is generally a polyamic acid, a polyamic acid ester, a polyamic acid amide, or a partial imide thereof. And a polyimide precursor in which those structures are mixed. Among them, polyamic acid, a partially imidized product thereof, and a mixture thereof are preferable.

The polyimide precursor is prepared, for example, by mixing a tetracarboxylic dianhydride which gives a residue represented by W in the general formula (I) and a diamine compound which gives a residue represented by R, preferably at a temperature of 100 ° C. or lower. Preferably 80 ° C
It is obtained by reacting below. In this case, it is mainly composed of polyamic acid, but may be partially imidized or may be a mixture. The polyimide and the polyimide precursor are preferably soluble in the solvent of the composition for a liquid crystal alignment film.

The polyimide used in the composition of the present invention has a repeating unit represented by the above general formula (I), and the polyimide precursor is a repeating unit which can become a repeating unit represented by the above general formula (I) by ring closure. Has units. In the general formula (I), the tetravalent organic group represented by W is generally two acid anhydride groups (—CO—O—CO 2) of the tetracarboxylic dianhydride used as a raw material.
-), And the divalent organic group represented by R is generally a divalent compound of the diamine compound used as a raw material.
It is a residue excluding _two amino groups (-NH2).

The polyimide or polyimide precursor used in the composition of the present invention uses an aromatic diamine which gives a specific residue represented by the above general formula (II) or (III). The effect increases,
It shows good characteristics for improving the orientation. Among them, R ¹ , R ² , R
^At least one of R ³ and R ⁴ is — (CH ₂ ) _n —CH ₃
It is preferable that

As the aromatic diamine providing a specific residue represented by the general formula (II) or (III), 2,3,5,
6-tetramethyl-1,4-phenylenediamine, 2,
3,5,6-tetraethyl-1,4-phenylenediamine, 2,5-dimethyl-1,4-phenylenediamine,
2,5, -dimethyl-1,3-phenylenediamine,
2,5, -diethyl-1,4-phenylenediamine,
2,5-diethyl-1,3-phenylenediamine, p-
Phenylenediamine, m-phenylenediamine, 2,
4,6-trimethyl-1,3-phenylenediamine,
2,4,6-triethyl-1,3-phenylenediamine and the like. In order to obtain good orientation, it is preferable to use 50 mol% or more of the total number of repeating units, and to make it 70 mol% or more. Is more preferable. The ratio can be adjusted by, for example, making the mixing ratio of the diamine to the total diamine used as the material the same. These diamines are used alone or in combination of two or more.

Other diamine compounds which provide the residue represented by R in the general formula (I) include 2,2'-bis (trifluoromethyl) -benzidine and 2,2'-bis (trifluoromethoxy)- Benzidine, 2-trifluoromethyl-benzidine, 2-trifluoromethoxy-benzidine, 2,2'-bis (pentafluoroethyl) -benzidine, 2,2'-bis (pentafluoroethoxy) -benzidine, 2-pentafluoro Ethyl-benzidine, 2-pentafluoroethoxy-benzidine,
2,2'-bis (heptafluoropropane) -benzidine, 2,2'-bis (heptafluoroproxy) -benzidine, 2-heptafluoropropane-benzidine,
-Heptafluoroproxy-benzidine, 2-pentafluoroethoxy-benzidine, 2,2'-bis (heptadecafluorooctane) -benzidine, 2,2'-bis (heptadecafluorooctoxy) -benzidine, 2-
Heptadecafluorooctane-benzidine, 2-heptadecafluorooctoxy-benzidine, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenyl sulfone,
4,4'-diaminodiphenyl sulfide, 3,4'-
Diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, bis (4- (3-aminophenoxy) phenyl) sulfone, bis (4- (4-aminophenoxy) phenyl) sulfone, bis (4- (4-aminophenoxy) ) Phenyl) sulfide, bis (4- (3-
Aminophenoxy) phenyl) sulfide, 4,4'-
Diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 2,4'-diaminodiphenyl ether, 4,4 '
-Diaminodiphenylmethane, 2,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane,
3,3'-diaminodiphenylmethane, 2-bis (4-
(4-aminophenoxy) phenyl) propane, 2,2
-Bis (4- (4-aminophenoxy) phenyl) hexafluoropropane, 2,2-bis (4- (3-aminophenoxy) phenyl) hexafluoropropane, 2,
2-bis (4-aminophenoxy) hexafluoropropane, 1,6-hexamethylenediamine, 1,8-octamethylenediamine, 1,10-decamethylenediamine, 1,12-dodecamethylenediamine, azelaic dihydrazide, sebacin Acid dihydrazide, 2,6-naphthoic acid dihydrazide, 2,4'-diamino-3-methyl-stearylphenyl ether, 2,4'-diamino-
3-methyl-lauryl phenyl ether, 2,4'-diamino-3-methyl-palmityl phenyl ether,
2,4'-diamino-1-octyloxybenzene,
2,2-bis (4- (4-aminophenoxy) phenyl) octane, 2,2-bis (4- (4-aminophenoxy) phenyl) tridecane, 2,2-bis (4- (4
-Aminophenoxy) phenyl) pentadecane, bis (4- (4-aminobenzoyloxy) benzoic acid) octane, bis (4- (4-aminobenzoyloxy) benzoic acid) decane, bis (4- (4-aminobenzoyloxy) ) Benzoic acid) dodecane, bis (4- (4-aminobenzoyloxy) benzoic acid) methylcyclohexane, bis (4- (4-aminobenzoyloxy) benzoic acid) methane, bis (4- (3-aminobenzoyloxy) (Benzoic acid) butane, diaminosiloxane, 1,3-di (3-aminopropyl) -1,1,3,3-tetramethyldisiloxane, and the like. These may be used alone or in combination of two or more. Can be In particular, to reduce the pretilt angle and increase the contrast ratio, it is preferable to use a diamine having no fluorine compound.

On the other hand, tetracarboxylic dianhydride which gives a residue represented by W in the above general formula (I) includes:
Oxydiphthalic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 1,2,3,4
-Butanetetracarboxylic dianhydride, 1,2,4,5-
Pentanetetracarboxylic dianhydride, 1,2,3,4-
Cyclobutanetetracarboxylic dianhydride, 1,2,3
4-cyclopentanetetracarboxylic dianhydride, 1,
2,4,5-cyclohexanetetracarboxylic dianhydride, bicyclo (2,2,2) oct-7-ene-2,
3,5,6-tetracarboxylic dianhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalenesuccinic dianhydride, pyromellitic dianhydride, 3,
3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxylphenyl)
Hexafluoropropanoic dianhydride, octyl succinic dianhydride, dodecyl succinic dianhydride, octyl malonic dianhydride, dimethylene bis trimellitate dianhydride, trimethylene bis trimellitate dianhydride, tetra Methylene bis trimellitate dianhydride, pentamethylene bis trimellitate dianhydride, hexamethylene bis trimellitate dianhydride, octamethylene bis trimellitate dianhydride, decamethylene bis trimellitate dianhydride, dodeca Methylene bis trimellitate dianhydride, hexadecamethylene bis trimellitate dianhydride, methylene-1,2-bis (1,3-dihydro-
1,3-dioxo-5-isobenzofuranyl) diether, propylene-1,3-bis (1,3-dihydro-
(1,3-dioxo-5-isobenzofuranyl) diether, 1,3-cyclohexanebistrimellitate dianhydride, 1,4-cyclohexanebistrimellitate dianhydride, 1,2-cyclohexanebistrimellitate acid Examples thereof include dianhydrides, which can be used alone or in combination of two or more.

Of these, the use of oxydiphthalic dianhydride is particularly preferred because it has an effect on stabilizing the orientation and the pretilt angle. From the viewpoint of the above effect, the content of the repeating unit having W derived from oxydiphthalic dianhydride is preferably at least 30 mol% of the total number of repeating units. This ratio can be adjusted by converting at least 30 mol% of the total carboxylic dianhydride used as a raw material to oxydiphthalic dianhydride.

In the present invention, the ratio of the total number of moles of the diamine compound to the number of moles of the acid dianhydride is preferably in the range of 0.8 to 1.2, more preferably 1.0. Can be done. As the inert solvent that can be used at this time, it is not necessary to dissolve all of the above monomers, but one that dissolves the generated polyamic acid is preferable. For example, N-methyl-2-pyrrolidone, N ,
N-dimethylformamide, N, N-dimethylacetamide, γ-butyrolactone, ε-caprolactone, γ-
Examples thereof include caprolactone, γ-valerolactone, dimethyl sulfoxide, 1,4-dioxane, and cyclohexanone, and two or more of these may be used in combination.

In the present invention, the solid content of the composition for liquid crystal alignment film (varnish) is preferably 1 to 20% by weight, more preferably 3 to 15% by weight. When the concentration is less than 1% by weight, the film thickness after application becomes thin, and a good film may not be obtained. When the concentration exceeds 20% by weight, the viscosity becomes high. Poor coating properties also tend to be inferior.

Further, a solvent for improving the wettability to the printing medium can be added before or after the reaction. As these solvents, for example, ethyl cellosolob,
Ethyl cellosorb acetate, butyl cellosorb, butyl cellosorb acetate, xylene, toluene, 1-ethoxy-2-acetoxypropane, diisobutyl ketone, methyl-n-hexyl ketone, and the like.

In the present invention, the obtained composition containing the polyimide precursor is preferably used as it is as a composition for a liquid crystal alignment film, but if necessary, it may be used as a composition containing a ring-closed polyimide. Can be.
The ring closing reaction is performed by (a) a method of heating a polyimide precursor,
(Ii) A method in which a dehydrating agent and a dehydration ring-closing catalyst are added to a polyimide precursor such as polyamic acid to cause a ring-closing reaction, and if necessary, further heating is performed.

In the method (a) obtained by heating, the reaction temperature is preferably from 130 to 170 ° C. When the reaction temperature is lower than 100 ° C., the dehydration ring-closing reaction does not sufficiently proceed, and when the reaction temperature exceeds 200 ° C., the thermal imidization and the decrease in molecular weight are observed at the same time. In the method (b), as the dehydrating agent, for example, acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used. The amount of the dehydrating agent used is preferably 1 to 20 mol per 1 mol of the repeating unit of the polyimide precursor such as polyamic acid.

As the dehydration ring-closing catalyst, for example, tertiary amines such as pyridine, triethylamine, collidine and lutidine can be used. The amount of the dehydration ring-closing catalyst used is preferably 0.5 to 10 mol per 1 mol of the dehydrating agent. In addition, as an organic solvent used for the dehydration ring closure reaction, an organic solvent used for synthesizing a polyamic acid can be exemplified.

As a method of forming a polyimide film as a liquid crystal alignment film, a spin coating method, a dipping method, a printing method, a spraying method and the like can be mentioned. More preferably, the production of a resin film by a flexographic printing machine, which easily retains the varnish and transfers a large amount to a printing medium, is more preferable. The printing medium used at this time includes a plastic substrate, a glass substrate, a silicon wafer, and the like.

The composition for a liquid crystal alignment film of the present invention comprises a silane coupling agent for improving the adhesion to glass.
A coupling agent such as a titanium coupling agent can be added.

Examples of the coupling agent include γ-
Aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltripropoxysilane, γ-aminopropyltributoxysilane,
γ-aminoethyltriethoxysilane, γ-aminoethyltrimethoxysilane, γ-aminoethyltripropoxysilane, γ-aminoethyltributoxysilane, γ-
Aminobutyltriethoxysilane, γ-aminobutyltrimethoxysilane, γ-aminobutyltripropoxysilane, γ-aminobutyltributoxysilane, and the like, and examples of the titanium coupling agent include γ-aminopropyl Triethoxytitanium, γ-aminopropyltrimethoxytitanium, γ-aminopropyltripropoxytitanium, γ-aminopropyltributoxytitanium, γ-aminoethyltriethoxytitanium, γ-aminoethyltrimethoxytitanium, γ-aminoethyltripropoxy Titanium, γ-aminoethyltributoxytitanium, γ-aminobutyltriethoxytitanium, γ-aminobutyltrimethoxytitanium, γ-aminobutyltripropoxytitanium, γ-aminobutyltributoxytitanium and the like can be mentioned. These may be used in combination of two or more.
The amount used at this time is 0.5 to 100 parts by weight of the resin.
It is preferable to set it to 5 parts by weight.

When the composition for a liquid crystal alignment film of the present invention contains a polyimide precursor, a polyimide film is formed by heat drying and dehydration ring closure. The heating temperature is generally 100 to 3
It is 50 degreeC, Preferably it is 110-230 degreeC. Further, for a plastic substrate, it is preferable to heat in the range of 120 to 160 ° C. The heating time is usually 1 minute to 6 hours, preferably 1 minute to 3 hours. The thickness of the formed polyimide film is usually 0.01 to 3 μm.

In particular, in order to obtain good display characteristics in the IPS mode liquid crystal display device, it is necessary to make the cell gap uniform. Therefore, it is required to fill the steps of the comb-teeth electrode to improve the flatness. It preferably has a thickness of 0.05 to 1 μm. In order to further obtain a high contrast ratio, the pretilt angle after the rubbing treatment is preferably 2 degrees or less, and more preferably the pretilt angle is 1 degree or less.

The composition for a liquid crystal alignment film of the present invention is previously coated on a transparent electrode such as ITO (Indium Tin Oxide) or a transparent substrate such as glass or plastic film with silicon nitride by using a spinner, a printing machine or the like. Then, if necessary, a heat curing treatment can be performed to form a resin film.

Examples of the liquid crystal display element substrate on which the liquid crystal alignment film is formed include glass such as fluorinated glass having good smoothness, polyester such as polyethylene terephthalate and polybutylene terephthalate, epoxy resin, phenol resin, and the like. Polyimide, polycarbonate, polysulfone, polyethersulfone, polyetherimide, acetylcellulose, polyamino acid ester, heat-resistant resin such as aromatic polyamide, polystyrene,
Polyacrylate, polymethacrylate,
Plastic films formed from vinyl polymers such as polyacrylamide, polyethylene, and polypropylene, fluorine-containing resins such as polyvinylidene fluoride, and denatured products thereof, and the like can be given.

The polyimide film formed on the substrate is used as a liquid crystal alignment film by subjecting the surface to a rubbing treatment. A liquid crystal display device can be obtained by a known method using the liquid crystal sandwiching substrate having the liquid crystal alignment film obtained as described above. As the liquid crystal sandwiched between the substrates, a material suitable for each of TN, STN, TFT, and FLC (ferroelectric liquid crystal) is used depending on the type of the liquid crystal display element.

A spacer is used to secure a gap between both alignment films. Glass fiber,
Glass beads, plastic beads, metal oxide particles such as alumina and silica are used.

The liquid crystal display of the present invention is not particularly limited except that it has the liquid crystal alignment film. As a structure of the liquid crystal display device, (1) a display pixel, a TFT, and an electrode group are formed on a substrate, and a liquid crystal alignment film is formed on the substrate via an insulating layer. (2) a liquid crystal display device provided with a deflecting means for changing a deflection characteristic for changing an optical characteristic of the liquid crystal layer, wherein the liquid crystal alignment film is formed of the composition for a liquid crystal alignment film; A) a pixel electrode is formed on a substrate by a scanning signal electrode, a video signal electrode, a pixel electrode, a common electrode, and a TFT, and a liquid crystal alignment film is disposed on the substrate via an insulating layer, and the liquid crystal layer is sandwiched between the substrates. The electrode group is configured to apply an electric field substantially parallel to the substrate surface to the liquid crystal layer, and the electrode group includes a deflecting unit that changes a deflection characteristic that changes an optical characteristic of the liquid crystal layer. Was In crystal display device, the liquid crystal alignment film wherein liquid crystal display device which is formed by a liquid crystal alignment film composition.

[0034]

The present invention will be described below in more detail with reference to examples.

Synthesis Example 1 192.61 g of N-methyl-2-pyrrolidone was added to a four-neck separable flask equipped with a thermometer, a stirrer, a condenser tube and a nitrogen inlet tube, and p-phenylenediamine was added to the flask. After dissolving 26 g (0.1 mol), 1,2,2
17.46 g of 3,4-butanetetracarboxylic dianhydride
(0.07 mol), oxydiphthalic dianhydride 24.8
After adding 2 g (0.03 mol) and stirring at room temperature for 16 hours, the viscosity was adjusted to obtain a 15% by weight polyamic acid varnish. The viscosity was 3500 in an E-type viscometer (25 ° C.)
mPa · s.

The obtained polyamic acid varnish contains one part of resin.
After adding weight% of γ-aminopropyltriethoxysilane, it was diluted with N-methyl-2-pyrrolidone and butyl cellosolve so as to obtain 4% by weight of polyamic acid varnish. The viscosity of the obtained polyamic acid varnish A is 30 mP.
a · s.

Synthesis Example 2 137.80 g of N-methyl-2-pyrrolidone was added to a four-neck separable flask equipped with a thermometer, a stirrer, a cooling tube and a nitrogen inlet tube. 8.21 g of 6-tetramethyl-1,4-phenylenediamine (0.
05 mol), 4,4'-diaminodiphenylmethane 9.
After dissolving 91 g (0.05 mol), 3,3 ',
4,4'-benzophenonetetracarboxylic dianhydride 1
After adding 6.11 g (0.05 mol) and 15.51 g (0.05 mol) of oxydiphthalic dianhydride and stirring at room temperature for 16 hours, the viscosity was adjusted to obtain a 15% by weight polyamic acid varnish. . The viscosity was 3000 mPa · s in an E-type viscometer (25 ° C.).

The obtained polyamic acid varnish contains one part of resin.
After adding weight% of γ-aminopropyltriethoxysilane, it was diluted with N-methyl-2-pyrrolidone and butyl cellosolve so as to obtain 4% by weight of polyamic acid varnish. The viscosity of the obtained polyamic acid varnish B is 25 mP.
a · s.

Synthesis Example 3 N-methyl-2-pyrrolidone 2 was placed in a four-neck separable flask equipped with a thermometer, a stirrer, a cooling tube and a nitrogen inlet tube.
49.75 g was added, and to this, 16.41 g of 2,3,5,6-tetramethyl-1,4-phenylenediamine (0.41 g) was added.
(1 mol), and 3.94 g of 3,3 ', 4,4'-bicyclohexyltetracarboxylic dianhydride (0.94 g).
03 mol), 21.72 g of oxydiphthalic dianhydride
(0.07 mol) and stirred at room temperature for 16 hours.
The viscosity was adjusted to obtain a polyamic acid varnish of 15% by weight. Viscosity is 3000 mPa · E-type viscometer (25 ° C)
s.

The obtained polyamic acid varnish has a resin content of 1%.
After adding weight% of γ-aminopropyltriethoxysilane, it was diluted with N-methyl-2-pyrrolidone and butyl cellosolve so as to obtain 4% by weight of polyamic acid varnish. The viscosity of the obtained polyamic acid varnish C is 25 mP.
a · s.

Synthesis Example 4 N-methyl-2-pyrrolidone 8 was placed in a four-neck separable flask equipped with a thermometer, a stirrer, a cooling tube and a nitrogen inlet tube.
5.13 g were added thereto, and 2,4,6-trimethyl-
After dissolving 15.02 g (0.1 mol) of 1,3-phenylenediamine, oxydiphthalic dianhydride 31.
After adding 02 g (0.1 mol) and stirring at room temperature for 16 hours, the viscosity was adjusted to obtain a 15% by weight polyamic acid varnish. The viscosity was 2800 in an E-type viscometer (25 ° C.)
mPa · s.

The polyamic acid varnish thus obtained was added with a resin component.
After adding weight% of γ-aminopropyltriethoxysilane, it was diluted with N-methyl-2-pyrrolidone and butyl cellosolve so as to obtain 4% by weight of polyamic acid varnish. The viscosity of the obtained polyamic acid varnish D is 23 mP.
a · s.

Comparative Synthesis Example 1 173.58 g of N-methyl-2-pyrrolidone was added to a four-neck separable flask equipped with a thermometer, a stirrer, a condenser tube and a nitrogen inlet tube, and 4,4'- After dissolving 20.02 g (0.1 mol) of diaminodiphenyl ether, 31.02 g (0.1 mol) of pyromellitic dianhydride was added, and the mixture was stirred at room temperature for 16 hours. % Polyamic acid varnish was obtained. The viscosity is E
It was 3500 mPa · s in a mold viscometer (25 ° C.).

The polyamic acid varnish thus obtained was added with a resin component.
After adding weight% of γ-aminopropyltriethoxysilane, it was diluted with N-methyl-2-pyrrolidone and butyl cellosolve so as to obtain 4% by weight of polyamic acid varnish. The viscosity of the obtained polyamic acid varnish E is 30 mP.
a · s.

Comparative Synthesis Example 2 N-methyl-2-pyrrolidone 5 was placed in a four-neck separable flask equipped with a thermometer, a stirrer, a cooling tube and a nitrogen inlet tube.
And 9.2 g of 2,2'-bis (4- (4
After dissolving 49.04 g (0.1 mol) of -aminophenoxy) phenyl) hexafluoropropane,
14.71 g (0.05 mol) of 3 ', 4,4'-biphenyltetracarboxylic dianhydride and 14.71 g (0.05 mol) of decamethylenebistrimellitate dianhydride were added, and the mixture was added at room temperature for 16 hours. After stirring, adjust the viscosity.
A polyamic acid varnish of 5% by weight was obtained. The viscosity was 2800 mPa · s in an E-type viscometer (25 ° C.).

The polyamic acid varnish thus obtained was added with a resin component.
After adding weight% of γ-aminopropyltriethoxysilane, it was diluted with N-methyl-2-pyrrolidone and butyl cellosolve so as to obtain 4% by weight of polyamic acid varnish. The viscosity of the obtained polyamic acid varnish F was 23 mPa ·
s.

Example 1 The varnish A obtained in Synthesis Example 1 was spin-coated on a glass substrate on which an ITO electrode was formed, and was heated on a hot plate at 80 ° C. for 2 minutes and in an oven at 200 ° C. for 30 minutes. Thus, a polyimide film having a thickness of 0.1 μm was obtained. The substrates were combined so that the orientation direction of the polyimide became 180 degrees by rubbing treatment, and the periphery was sealed. The rubbing strength was determined by T. Uchida et al. In Liquid Crystal, 5, p. 1127-11.
37 (1989).

[0048]

Rubbing strength: L (mm) = Nl (1 + 2πrn) / v (where N: number of rubbing (times), l: pushing amount of rubbing roll (mm), r: radius of rubbing roll (m)
m), n: number of rotations of the rubbing roll (s ^-1 ), v: stage moving speed (mm / s)

This time, N = 1, l = 0.4 mm, r = 22
mm, n = 7s ^-1 , v = 6mm / s, rubbing fiber: Yoshikawa Kako
A rubbing material YA-18-R (rayon) manufactured by Co., Ltd. was set, and rubbing treatment was performed at L = 65 mm.

No scraping or peeling was observed on the rubbed polyimide film. The cell gap was 25 μm with the liquid crystal sealed, and a polyethylene terephthalate film was interposed. The nematic liquid crystal MLC-
2042 (trade name, manufactured by Merck) was injected by a vacuum impregnation method. An isotropic treatment was performed at 110 ° C. for 20 minutes at a phase transition temperature of 80 ° C. or higher to obtain a pretilt angle evaluation liquid crystal display device (hereinafter abbreviated as anti-parallel cell). The prepared liquid crystal display element had good orientation. When the pretilt angle was evaluated by the crystal rotation method, it was 1.0 degree.

Next, the varnish A obtained in Synthesis Example 1 was applied to a glass substrate (lower substrate) and a glass substrate (upper substrate) on which comb-tooth electrodes having an electrode width of 15 μm, an electrode width of 10 μm, and an electrode height of 0.05 μm were formed. The substrate was spin-coated so as to have a thickness of 0.1 μm, and was heated on a hot plate at 80 ° C. for 2 minutes and in an oven at 200 ° C. for 30 minutes to obtain a polyimide film. Subsequently, the substrates were combined by setting the rubbing directions of the polyimides to be substantially parallel to each other and forming an angle of 15 degrees with the direction of the applied voltage, and sealing the periphery. The cell gap is obtained by dispersing the polymer beads between the substrates and filling the liquid crystal with the liquid crystal.
The thickness was 5 μm.

MLC-2042 is sealed between the substrates,
Heat treatment was performed at 110 ° C., which is higher than the phase transition temperature, for 20 minutes to form an IPS mode liquid crystal display device (hereinafter abbreviated as IPS liquid crystal cell). Thereafter, the panel is sandwiched between two polarizing plates G1220D (trade name, manufactured by Nitto Denko Corporation), and the polarization transmission axis of one of the polarizing plates is substantially parallel to the rubbing direction, and the other is orthogonal to the rubbing direction to obtain a normally closed characteristic. Was. The liquid crystal alignment was good. The voltage holding ratio was 25 ° C., cycle 1
It was evaluated at 6.5 ms, frequency 30 Hz, amplitude 6 V, and offset 0 V, and showed a value of 99.2%.

The residual DC voltage was measured by the flicker elimination method. A rectangular wave having an amplitude of 3.0 V and a frequency of 30 Hz and an offset voltage of 1.0 V are applied to the IPS liquid crystal cell for 30 minutes,
Immediately after the offset voltage was set to 0 V, a voltage that minimizes flicker was measured, and this value was defined as a residual DC voltage. 25 ° C
Was 120 mV. And this IPS
The contrast ratio of the liquid crystal cell is determined by measuring the light transmittance under no voltage (dark state) and the light transmittance under a voltage (bright state) at which the light transmittance is maximized. The contrast ratio was determined. The contrast ratio was 350.

Example 2 A varnish A was obtained in the same manner as in Example 1 to obtain a polyimide film having a thickness of 0.1 μm. This is repeated N = 1 time, l = 0.4 mm, r = 22
mm, n = 5 s ^-1 , v = 24 mm / s, rubbing fiber: rubbing material YA-18-R manufactured by Yoshikawa Kako Co., Ltd., L = 12
Rubbing treatment was performed in mm. Rubbing and peeling were not observed on the rubbed polyimide film. Thereafter, an anti-parallel cell and an IPS liquid crystal cell were manufactured under the same conditions as in Example 1. Orientation, pretilt angle, voltage holding ratio,
Table 1 summarizes the results of the residual DC voltage and the contrast ratio.

Example 3 A varnish A was obtained in the same manner as in Example 1 to obtain a polyimide film having a thickness of 0.1 μm. This is repeated N = 1 time, l = 0.4 mm, r = 22
mm, n = 12 s ⁻¹ , v = 2 mm / s, rubbing fiber: rubbing material YA-18-R manufactured by Yoshikawa Kako Co., Ltd., L = 33
Rubbing was performed at 2 mm. Rubbing and peeling were not observed on the rubbed polyimide film. Thereafter, an anti-parallel cell and an IPS liquid crystal cell were manufactured under the same conditions as in Example 1. Table 1 summarizes the results of orientation, pretilt angle, voltage holding ratio, residual DC voltage, and contrast ratio.

Example 4 A varnish B was obtained in the same manner as in Example 1 to obtain a polyimide film having a thickness of 0.1 μm. This is repeated N = 1 time, l = 0.4 mm, r = 22
mm, n = 7s ^-1 , v = 6mm / s, rubbing fiber: Yoshikawa Kako
Set as rubbing material YA-18-R manufactured by Co., Ltd., L = 65 mm
Was rubbed. Rubbing and peeling were not observed on the rubbed polyimide film. Thereafter, an anti-parallel cell and an IPS liquid crystal cell were manufactured under the same conditions as in Example 1. Table 1 summarizes the results of orientation, pretilt angle, voltage holding ratio, residual DC voltage, and contrast ratio.

Example 5 A varnish B was obtained in the same manner as in Example 1 to obtain a polyimide film having a thickness of 0.1 μm. This is repeated N = 1 time, l = 0.4 mm, r = 22
mm, n = 5 s ^-1 , v = 24 mm / s, rubbing fiber: rubbing material YA-18-R manufactured by Yoshikawa Kako Co., Ltd., L = 12
Rubbing treatment was performed in mm. Rubbing and peeling were not observed on the rubbed polyimide film. Thereafter, an anti-parallel cell and an IPS liquid crystal cell were manufactured under the same conditions as in Example 1. Orientation, pretilt angle, voltage holding ratio,
Table 1 summarizes the results of the residual DC voltage and the contrast ratio.

Example 6 A varnish B was obtained in the same manner as in Example 1 to obtain a polyimide film having a thickness of 0.1 μm. This is repeated N = 1 time, l = 0.4 mm, r = 22
mm, n = 12 s ⁻¹ , v = 2 mm / s, rubbing fiber: rubbing material YA-18-R manufactured by Yoshikawa Kako Co., Ltd., L = 33
Rubbing was performed at 2 mm. Rubbing and peeling were not observed on the rubbed polyimide film. Thereafter, an anti-parallel cell and an IPS liquid crystal cell were manufactured under the same conditions as in Example 1. Table 1 summarizes the results of orientation, pretilt angle, voltage holding ratio, residual DC voltage, and contrast ratio.

Example 7 A varnish C was obtained in the same manner as in Example 1 to obtain a polyimide film having a thickness of 0.1 μm. This is repeated N = 1 time, l = 0.4 mm, r = 22
mm, n = 7s ^-1 , v = 6mm / s, rubbing fiber: Yoshikawa Kako
Set as rubbing material YA-18-R manufactured by Co., Ltd., L = 65 mm
Was rubbed. Rubbing and peeling were not observed on the rubbed polyimide film. Thereafter, an anti-parallel cell and an IPS liquid crystal cell were manufactured under the same conditions as in Example 1. Table 1 summarizes the results of orientation, pretilt angle, voltage holding ratio, residual DC voltage, and contrast ratio.

Example 8 A varnish C was obtained in the same manner as in Example 1 to obtain a polyimide film having a thickness of 0.1 μm. This is repeated N = 1 time, l = 0.4 mm, r = 22
mm, n = 5 s ^-1 , v = 24 mm / s, rubbing fiber: rubbing material YA-18-R manufactured by Yoshikawa Kako Co., Ltd., L = 12
Rubbing treatment was performed in mm. Rubbing and peeling were not observed on the rubbed polyimide film. Thereafter, an anti-parallel cell and an IPS liquid crystal cell were manufactured under the same conditions as in Example 1. Orientation, pretilt angle, voltage holding ratio,
Table 1 summarizes the results of the residual DC voltage and the contrast ratio.

Example 9 A varnish C was obtained in the same manner as in Example 1 to obtain a polyimide film having a thickness of 0.1 μm. This is repeated N = 1 time, l = 0.4 mm, r = 22
mm, n = 12 s ⁻¹ , v = 2 mm / s, rubbing fiber: rubbing material YA-18-R manufactured by Yoshikawa Kako Co., Ltd., L = 33
Rubbing was performed at 2 mm. Rubbing and peeling were not observed on the rubbed polyimide film. Thereafter, an anti-parallel cell and an IPS liquid crystal cell were manufactured under the same conditions as in Example 1. Table 1 summarizes the results of orientation, pretilt angle, voltage holding ratio, residual DC voltage, and contrast ratio.

Example 10 A varnish D was prepared in the same manner as in Example 1 to obtain a polyimide film having a thickness of 0.1 μm. This is repeated N = 1 time, l = 0.4 mm, r = 22
mm, n = 7s ^-1 , v = 6mm / s, rubbing fiber: Yoshikawa Kako
Set as rubbing material YA-18-R manufactured by Co., Ltd., L = 65 mm
Was rubbed. Rubbing and peeling were not observed on the rubbed polyimide film. Thereafter, an anti-parallel cell and an IPS liquid crystal cell were manufactured under the same conditions as in Example 1. Table 1 summarizes the results of orientation, pretilt angle, voltage holding ratio, residual DC voltage, and contrast ratio.

Example 11 A varnish D was prepared in the same manner as in Example 1 to obtain a polyimide film having a thickness of 0.1 μm. This is repeated N = 1 time, l = 0.4 mm, r = 22
mm, n = 5 s ^-1 , v = 24 mm / s, rubbing fiber: rubbing material YA-18-R manufactured by Yoshikawa Kako Co., Ltd., L = 12
Rubbing treatment was performed in mm. Rubbing and peeling were not observed on the rubbed polyimide film. Thereafter, an anti-parallel cell and an IPS liquid crystal cell were manufactured under the same conditions as in Example 1. Orientation, pretilt angle, voltage holding ratio,
Table 1 summarizes the results of the residual DC voltage and the contrast ratio.

Example 12 A varnish D was prepared in the same manner as in Example 1 to obtain a polyimide film having a thickness of 0.1 μm. This is repeated N = 1 time, l = 0.4 mm, r = 22
mm, n = 12 s ⁻¹ , v = 2 mm / s, rubbing fiber: rubbing material YA-18-R manufactured by Yoshikawa Kako Co., Ltd., L = 33
Rubbing was performed at 2 mm. Rubbing and peeling were not observed on the rubbed polyimide film. Thereafter, an anti-parallel cell and an IPS liquid crystal cell were manufactured under the same conditions as in Example 1. Table 1 summarizes the results of orientation, pretilt angle, voltage holding ratio, residual DC voltage, and contrast ratio.

Comparative Example 1 A varnish E was obtained in the same manner as in Example 1 to obtain a polyimide film having a thickness of 0.1 μm. This is repeated N = 1 time, l = 0.4 mm, r = 22
mm, n = 7s ^-1 , v = 6mm / s, rubbing fiber: Yoshikawa Kako
Set as rubbing material YA-18-R manufactured by Co., Ltd., L = 65 mm
Was rubbed. Rubbing and peeling were not observed on the rubbed polyimide film. Thereafter, an anti-parallel cell and an IPS liquid crystal cell were manufactured under the same conditions as in Example 1. Table 1 summarizes the results of orientation, pretilt angle, voltage holding ratio, residual DC voltage, and contrast ratio.

Comparative Example 2 A varnish E was obtained in the same manner as in Example 1 to obtain a polyimide film having a thickness of 0.1 μm. This is repeated N = 1 time, l = 0.4 mm, r = 22
mm, n = 5 s ^-1 , v = 24 mm / s, rubbing fiber: rubbing material YA-18-R manufactured by Yoshikawa Kako Co., Ltd., L = 12
Rubbing treatment was performed in mm. Rubbing and peeling were not observed on the rubbed polyimide film. Thereafter, an anti-parallel cell and an IPS liquid crystal cell were manufactured under the same conditions as in Example 1. Orientation, pretilt angle, voltage holding ratio,
Table 1 summarizes the results of the residual DC voltage and the contrast ratio.

Comparative Example 3 A varnish E was prepared in the same manner as in Example 1 to obtain a polyimide film having a thickness of 0.1 μm. This is repeated N = 1 time, l = 0.4 mm, r = 22
mm, n = 12 s ⁻¹ , v = 2 mm / s, rubbing fiber: rubbing material YA-18-R manufactured by Yoshikawa Kako Co., Ltd., L = 33
Rubbing was performed at 2 mm. Rubbing and peeling were not observed on the rubbed polyimide film. Thereafter, an anti-parallel cell and an IPS liquid crystal cell were manufactured under the same conditions as in Example 1. Table 1 summarizes the results of orientation, pretilt angle, voltage holding ratio, residual DC voltage, and contrast ratio.

Comparative Example 4 A varnish F was obtained in the same manner as in Example 1 to obtain a polyimide film having a thickness of 0.1 μm. This is repeated N = 1 time, l = 0.4 mm, r = 22
mm, n = 7s ^-1 , v = 6mm / s, rubbing fiber: Yoshikawa Kako
Set as rubbing material YA-18-R manufactured by Co., Ltd., L = 65 mm
Was rubbed. Rubbing and peeling were not observed on the rubbed polyimide film. Thereafter, an anti-parallel cell and an IPS liquid crystal cell were manufactured under the same conditions as in Example 1. Table 1 summarizes the results of orientation, pretilt angle, voltage holding ratio, residual DC voltage, and contrast ratio.

Comparative Example 5 A varnish F was prepared in the same manner as in Example 1 to obtain a polyimide film having a thickness of 0.1 μm. This is repeated N = 1 time, l = 0.4 mm, r = 22
mm, n = 5 s ^-1 , v = 24 mm / s, rubbing fiber: rubbing material YA-18-R manufactured by Yoshikawa Kako Co., Ltd., L = 12
Rubbing treatment was performed in mm. Rubbing and peeling were not observed on the rubbed polyimide film. Thereafter, an anti-parallel cell and an IPS liquid crystal cell were manufactured under the same conditions as in Example 1. Orientation, pretilt angle, voltage holding ratio,
Table 1 summarizes the results of the residual DC voltage and the contrast ratio.

Comparative Example 6 A varnish F was obtained in the same manner as in Example 1 to obtain a polyimide film having a thickness of 0.1 μm. This is repeated N = 1 time, l = 0.4 mm, r = 22
mm, n = 12 s ⁻¹ , v = 2 mm / s, rubbing fiber: rubbing material YA-18-R manufactured by Yoshikawa Kako Co., Ltd., L = 33
Rubbing was performed at 2 mm. Rubbing and peeling were not observed on the rubbed polyimide film. Thereafter, an anti-parallel cell and an IPS liquid crystal cell were manufactured under the same conditions as in Example 1. Table 1 summarizes the results of orientation, pretilt angle, voltage holding ratio, residual DC voltage, and contrast ratio.

[0071]

[Table 1]

The composition for a liquid crystal alignment film of the present invention is stable at a pretilt angle of 2 degrees or less irrespective of rubbing conditions, has a high voltage holding ratio, and has a low residual DC, as compared with the conventional composition for a liquid crystal alignment film. It can be seen that the voltage and the high contrast ratio are shown.

[0073]

The composition for a liquid crystal alignment film according to the present invention is stable at a pretilt angle of 2 degrees or less regardless of the rubbing conditions, and a good alignment function can be obtained. It is possible to provide a liquid crystal alignment film, a liquid crystal holding substrate, and a lateral electric field liquid crystal display device suitable for this.

Continued on front page F term (reference) 2H090 HB08Y HB09Y HC05 HC06 HC08 MA02 MA06 MA10 MB01 4F071 AA60 AF29 AG13 AH19 BC02 4J043 PA02 PA04 PA19 QB15 QB26 QB31 RA35 SA06 SA43 SA44 SA54 SA55 SA56 SA62 SA72 SB01 SB02 TA02 TA02 TA02 TA02 TA02 UA041 UA042 UA052 UA082 UA121 UA122 UA131 UA132 UA151 UA261 UA622 UB011 UB012 UB021 UB061 UB062 UB121 UB122 UB131 UB132 UB152 UB161 UB251 UB281 UB301 UB351 VA041 VA081 ZA09A09 Z09A09Z

Claims (9)

[Claims] 1. A compound of the general formula (I)(Wherein, W has a tetravalent organic group, and R is a divalent organic group.
Has a repeating unit represented by
At least a part of the total number of units is represented by a general formula as R
(II)Or the general formula (III):(Where R¹, R^Two, R^ThreeAnd R^FourAre independent of each other
Child or-(CH_Two)_n-CH _ThreeAnd n is an integer of 0 to 7
A) a polyimide having a divalent organic group represented by
A composition for a liquid crystal alignment film comprising the precursor. 2. The method according to claim 1, wherein at least 50 mol% of the total number of repeating units is represented by the general formula (II) or the general formula (II)
The composition for a liquid crystal alignment film according to claim 1, which has a diamine residue represented by I). 3. The composition for a liquid crystal alignment film according to claim 1, wherein at least a part of the total number of the repeating units has an oxydiphthalic dianhydride residue as a tetravalent organic group represented by W. object. 4. The composition for a liquid crystal alignment film according to claim 3, wherein at least 30 mol% of the total number of the repeating units has an oxydiphthalic dianhydride residue as W. 5. A liquid crystal alignment film obtained by rubbing a polyimide film formed from the composition for a liquid crystal alignment film according to claim 1. 6. The pre-tilt angle is equal to or less than 2 degrees.
The liquid crystal alignment film as described in the above. 7. A liquid crystal sandwiching substrate comprising the liquid crystal alignment film according to claim 5. 8. A liquid crystal display device comprising the liquid crystal holding substrate according to claim 7. 9. A horizontal electric field liquid crystal display device comprising the liquid crystal holding substrate according to claim 7.