JP2001228481A - Liquid crystal alignment film and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal alignment film formed from a polyamic acid and polyimide, which exhibits good alignment characteristics, has a high voltage holding rate and does not cause irregular contrast or display defects when a voltage is applied for a long time. SOLUTION: The liquid crystal alignment film consists of (a) a polymer having imide coupling units or a polymer having both of amic acid coupling units and imide coupling units, wherein the percentage of the imide coupling units to the total coupling units of the imide coupling units and amic acid coupling units in the polymer ranging is 30 to 100%, (b) the polar term in the surface tension of the film is >=10 dyn/cm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal alignment film and a liquid crystal display device. More specifically, in a liquid crystal display device which is excellent in voltage holding ratio and liquid crystal orientation, and particularly exhibits a threshold voltage of 3 V or less, a liquid crystal capable of preventing display defects such as contrast unevenness and display defects occurring after long-time voltage application. The present invention relates to an alignment film and the liquid crystal display device.

[0002]

2. Description of the Related Art Conventionally, a sandwich structure is formed by forming a layer of a nematic liquid crystal having a positive dielectric anisotropy between two substrates having a liquid crystal alignment film formed on the surface thereof through a transparent conductive film. And a TN (Twisted Nematic) liquid crystal cell having a long axis of the liquid crystal molecules twisted continuously by 90 degrees from one substrate to the other substrate. I have.

Further, by adding a chiral agent, a state in which the major axis of the liquid crystal molecules is continuously twisted over 180 degrees between the substrates is achieved, and an STN (Super Twisted Nem) utilizing the birefringence effect generated thereby is achieved.
Atic) type liquid crystal display elements also exist. More recently, a nematic liquid crystal layer having a homeotropic alignment state having negative dielectric anisotropy and a cholesteric liquid crystal layer having a helical axis parallel to the substrate normal are formed between opposing substrates. A guest-host type reflective liquid crystal display device in which a dye is added to a liquid crystal display device has also been developed. Orientation of the liquid crystal in these liquid crystal display elements is usually exhibited by a liquid crystal alignment film subjected to a rubbing treatment. Here, as a material of a liquid crystal alignment film constituting a liquid crystal display element, polyimide, polyamide, polyester, and the like are conventionally known. In particular, polyimide is used in many liquid crystal display devices because of its excellent heat resistance, affinity with liquid crystal, mechanical strength, and the like.

However, recently, liquid crystal display elements have been remarkably developed as high-performance display elements from the viewpoints of enlargement, weight reduction, and low power consumption, and accordingly, the required performance of liquid crystal alignment films has become increasingly severe. Is coming.
In particular, in a low voltage driving type liquid crystal display element for low power consumption, a demand for a voltage holding ratio and a reliability test for applying a voltage for a long time at a high temperature has become strict. However, a liquid crystal alignment film made of polyamic acid, which is a precursor of a conventionally known polyimide, or an imide polymer having a structure obtained by dehydrating and cyclizing the same, uses the liquid crystal alignment film. When a liquid crystal display device is prepared by the method described above, even if the liquid crystal display device has an excellent liquid crystal alignment capability and a stable pretilt angle, a sufficient voltage holding ratio cannot be obtained, or contrast unevenness during a reliability test of the liquid crystal display device.
Many objects have a problem that display defects occur. For this reason, a polyimide precursor having an alicyclic structure and a polyimide have a higher voltage holding ratio and a good result in a reliability test in many cases because the polyimide precursor and the polyimide have an alicyclic structure. It has become more frequent to use a liquid crystal alignment film. However, there has been a problem that a liquid crystal alignment film manufactured only based on such knowledge may not show durability against a sufficient reliability test.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyimide precursor, which is useful as a liquid crystal alignment film, comprising a polyamic acid and a polyimide. It is an object of the present invention to provide a liquid crystal alignment film which has high contrast and does not cause contrast unevenness and display defects when a voltage is applied for a long time. Another object of the present invention is to provide a liquid crystal display device provided with the liquid crystal alignment film of the present invention exhibiting the above excellent performance. Still other objects and advantages of the present invention will become apparent from the following description.

[0006]

SUMMARY OF THE INVENTION The above objects and advantages of the present invention are as follows. According to the present invention, (a) a polymer having an imide bond unit or both an amic acid bond unit and an imide bond unit are used. A liquid crystal alignment film comprising a polymer having a percentage of the number of imide bond units to the total number of imide bond units and amic acid bond units in the polymer of 30 to 100%, and (b) )
The liquid crystal alignment film is characterized in that the polar term of the surface tension is 10 dyn / cm or more. According to the present invention, the above objects and advantages of the present invention are secondly achieved by a liquid crystal display device including the liquid crystal alignment film of the present invention.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The liquid crystal alignment film in the present invention is usually formed by applying a liquid crystal alignment agent containing polyimide and / or a polyamic acid as a precursor thereof on a transparent electrode substrate, and then drying (normally, heating and drying), It is used after performing an alignment treatment on the film surface such as rubbing. Each of polyimide and polyamic acid can be used alone or in combination of two or more. Also,
When the liquid crystal alignment agent used in the present invention contains both polyimide and polyamic acid, a mixture of polyimide and polyamic acid may be contained, or a polymer having imide bond units and amide bond units May be contained. In the polymer, the imide bond unit and the amide bond unit may be contained at random or in a block shape.

In the liquid crystal alignment film of the present invention, in the step of applying and drying the above liquid crystal alignment agent on a substrate, heating and drying are performed to dehydrate and close the amide bond unit in the liquid crystal alignment agent to form an imide bond. It can also be a unit. The percentage of the number of imide bond units to the total number of imide bond units and amic acid bond units in the resulting polymer forming the liquid crystal alignment film of the present invention (hereinafter also referred to as “imidization ratio”) is 30. In particular, when used for a TN-TFT type element, it is preferably 30 to 70% because there is no image sticking and the reliability is high.

<Polyamic Acid> The polyamic acid used in the present invention is obtained by ring-opening polyaddition of a tetracarboxylic dianhydride and a diamine compound. [Tetracarboxylic dianhydride] Examples of the tetracarboxylic dianhydride used in the synthesis reaction of the polyamic acid, which is a precursor of polyimide, include butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutane Tetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride 1,1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3 ', 4,4'-dicyclohexyltetracarboxylic dianhydride 2,3,5-trica Ruboxycyclopentylacetic dianhydride, 3,5,6-tricarboxynorbornane-2-acetic dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, 1,3,3a,
4,5,9b-Hexahydro-5 (tetrahydro-2,5
-Dioxo-3-furanyl) -naphtho [1,2-c]-
Furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c]- Furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-5-ethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c]- Franc-
1,3-dione, 1,3,3a, 4,5,9b-hexahydro-7-methyl-5 (tetrahydro-2,5-dioxo-
3-furanyl) -naphtho [1,2-c] -furan-1,3
-Dione, 1,3,3a, 4,5,9b-hexahydro-7
-Ethyl-5 (tetrahydro-2,5-dioxo-3-
Furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5 (tetrahydro-2,5-dioxo-3- Furanyl) -naphtho [1,2-c] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-8-ethyl-5 (tetrahydro-2,5-dioxo-3- Furanyl) -naphtho [1,2-c] -furan-1,3-dione;
1,3,3a, 4,5,9b-Hexahydro-5,8-dimethyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3- Zeon,
5- (2,5-dioxotetrahydrofural) -3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, bicyclo [2,2,2] -oct-7-ene-2,
Aliphatic and alicyclic tetracarboxylic dianhydrides such as 3,5,6-tetracarboxylic dianhydride, compounds represented by the following formulas (I) and (II);

[0010]

Embedded image

(Wherein, R ¹ and R ⁴ represent a divalent organic group having an aromatic ring, R ² and R ³ represent a hydrogen atom or an alkyl group, and a plurality of R ² and R ³ are present. May be the same or different.) Pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4,4′-
Biphenylsulfonetetracarboxylic dianhydride, 1,4,
5,8-Naphthalenetetracarboxylic dianhydride, 2,3,
6,7-naphthalenetetracarboxylic dianhydride, 3,
3 ', 4,4'-biphenylethertetracarboxylic dianhydride, 3,3', 4,4'-dimethyldiphenylsilanetetracarboxylic dianhydride, 3,3 ', 4,4'-tetraphenylsilane Tetracarboxylic dianhydride, 1,2,3,
4-furantetracarboxylic dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenyl sulfone dianhydride 4,4'-bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride, 3,3 ', 4,4'-perfluoroisopropylidene diphthalic dianhydride, 3,3', 4 , 4'-biphenyltetracarboxylic dianhydride, bis (phthalic acid)
Phenylphosphine oxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride, m-phenylene-bis (triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4'- Diphenyl ether dianhydride, bis (triphenylphthalic acid) -4,
4'-diphenylmethane dianhydride, ethylene glycol-bis (anhydrotrimellitate), propylene glycol-bis (anhydrotrimellitate), 1,4-
Butanediol-bis (anhydrotrimellitate),
1,6-hexanediol-bis (anhydrotrimellitate), 1,8-octanediol-bis (anhydrotrimellitate), 2,2-bis (4-hydroxyphenyl) propane-bis (anhydrotrimellitate) Melitate) and aromatic tetracarboxylic dianhydrides such as compounds represented by the following formulas (1) to (4).
These are used alone or in combination of two or more.

[0012]

Embedded image

Of these, butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride Anhydride, 1,3-dimethyl-1,
2,3,4-cyclobutanetetracarboxylic dianhydride,
1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,
2,3,4-cyclobutanetetracarboxylic dianhydride,
1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3 ', 4,4'-dicyclohexyltetracarboxylic dianhydride 2,3,5-tricarboxycyclopentylacetic dianhydride, 3,5,6-tricarboxynorbornane-2-acetic dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, bicyclo [ 2.2.
2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, cis-3,7-dibutylcycloocta-
Compounds containing an aliphatic acid anhydride group such as 1,5-diene-1,2,5,6-tetracarboxylic dianhydride are preferred.

Examples of the diamine compound used in the synthesis reaction of the polyamic acid include p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylethane,
4,4′-diaminodiphenyl sulfide, 4,4′-diaminodiphenyl sulfone, 3,3′-dimethyl-4,
4'-diaminobiphenyl, 4,4'-diaminobenzanilide, 4,4'-diaminodiphenyl ether, 1,
5-diaminonaphthalene, 3,3-dimethyl-4,4'-
Diaminobiphenyl, 5-amino-1- (4′-aminophenyl) -1,3,3-trimethylindane, 6-amino-1- (4′-aminophenyl) -1,3,3-trimethylindane, 4,4'-diaminodiphenyl ether, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, , 2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-
Bis (4-aminophenyl) hexafluoropropane,
2,2-bis [4- (4-aminophenoxy) phenyl] sulfone, 1,4-bis (4-aminophenoxy)
Benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 9,9-bis (4-aminophenyl) -10-hydroanthracene, 2,7-diamino Fluorene, 9,9-
Bis (4-aminophenyl) fluorene, 4,4′-methylene-bis (2-chloroaniline), 2,2 ′, 5,
5'-tetrachloro-4,4'-diaminobiphenyl,
2,2'-dichloro-4,4'-diamino-5,5'-dimethoxybiphenyl, 3,3'-dimethoxy-4,4'-
Diaminobiphenyl, 1,4.4 '-(p-phenyleneisopropylidene) bisaniline, 4,4'-(m-phenyleneisopropylidene) bisaniline, 2,2'-bis [4- (4-amino-2-triene Fluoromethylphenoxy) phenyl] hexafluoropropane, 4,4'-
Aromatic diamines such as diamino-2,2′-bis (trifluoromethyl) biphenyl, 4,4′-bis [(4-amino-2-trifluoromethyl) phenoxy] -octafluorobiphenyl; 1,1-meta Xylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1,4-diaminocyclohexane , Isophoronediamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoindanylene dimethylenediamine, tricyclo [6,2,1,
0 ^2.7 ] -undecylenedimethyldiamine, aliphatic and alicyclic diamines such as 4,4'-methylenebis (cyclohexylamine); monosubstituted phenylenediamines represented by the following formula (III); and represented by the following formula (IV) Diaminoorganosiloxane;

[0015]

Embedded image

(Wherein R ⁵ represents —O—, —COO—,
OCO-, -NHCO-, -CONH- and -CO-
And R ⁶ represents a monovalent organic group having a steroid skeleton or a trifluoromethyl group. )

[0017]

Embedded image

(Wherein R ⁷ represents a hydrocarbon group having 1 to 12 carbon atoms, a plurality of R ^{7 s} may be the same or different, p is an integer of 1 to 3, and q is 1-2
It is an integer of 0. Examples include compounds represented by the following formulas (9) to (13). These diamine compounds can be used alone or in combination of two or more.

[0019]

Embedded image

(In the formula, y is an integer of 2 to 12, and z is an integer of 1 to 5.) Ratio of tetracarboxylic dianhydride and diamine compound to be used in the synthesis reaction of polyamic acid Is preferably a ratio in which the amount of the acid anhydride group contained in the tetracarboxylic dianhydride is 0.2 to 2 equivalents, more preferably 0.3 to 1.3 equivalents to 1 equivalent of the amino group contained in the diamine compound. This is a ratio equivalent to 4 equivalents. When the ratio of the acid anhydride group contained in the tetracarboxylic dianhydride is less than 0.2 equivalent,
In any case where the amount exceeds the equivalent, the molecular weight of the obtained polymer may be too small, and the coating property of the liquid crystal aligning agent may be poor.

The polyamic acid constituting the liquid crystal aligning agent in the present invention is synthesized by reacting a tetracarboxylic dianhydride with a diamine compound. The synthesis reaction of the polyamic acid is performed in an organic solvent, preferably at a temperature of 0 to 150 ° C, more preferably 0 to 100 ° C. If the reaction temperature is 0 ° C or lower, the solubility of the compound in a solvent may be poor, and if it exceeds 150 ° C, the molecular weight of the obtained polymer may decrease.

The organic solvent used for the synthesis of the polyamic acid is not particularly limited as long as it can dissolve the tetracarboxylic dianhydride, the diamine compound and the polyamic acid formed by the reaction. For example, γ-butyrolactone, N Aprotic systems such as -methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, tetramethylurea, hexamethylphosphoryltriamide, 1,3-dimethyl-2-imidazolidinone Polar solvents; phenolic solvents such as m-cresol, xylenol, phenol, halogenated phenol and the like can be mentioned. The amount (A) of the organic solvent used is such that the total amount (B) of the tetracarboxylic dianhydride and the diamine compound as the reaction raw materials becomes 0.1 to 30% by weight based on the total amount (A + B) of the reaction solution. It is preferred that

The above organic solvents include alcohols, ketones, esters which are poor solvents for polyamic acid,
Ethers, halogenated hydrocarbons, hydrocarbons and the like can be used in combination as long as the generated polyamic acid does not precipitate. Specific examples of such poor solvents include, for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol,
Triethylene glycol, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, diethyl oxalate,
Diethyl malonate, diethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethylene Glycol methyl ether acetate, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol methyl ether, dipropylene glycol ethyl ether Le, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, ethylene glycol ethyl ether acetate, 4
-Hydroxy-4-methyl-2-pentanone, ethyl 2-hydroxypropionate, ethyl lactate, methyl lactate,
Butyl lactate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, 3-
Methyl methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, 3-methyl-3-methoxybutanol, 3-ethyl-3-methoxybutanol, 2-methyl-2-methoxybutanol,
2-ethyl-2-methoxybutanol, 3-methyl-3
-Ethoxybutanol, 3-ethyl-3-ethoxybutanol, 2-methyl-2-ethoxybutanol, 2-ethyl-2-ethoxybutanol, tetrahydrofuran,
Dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-
Examples thereof include dichlorobenzene, hexane, heptane, octane, benzene, toluene, and xylene. These can be used alone or in combination of two or more.

By the above synthesis reaction, a polymer solution obtained by dissolving the polyamic acid is obtained. The polymer solution is poured into a large amount of a poor solvent to obtain a precipitate, and the precipitate is dried under reduced pressure to obtain a polyamic acid. Further, the polyamic acid can be purified by dissolving the polyamic acid in an organic solvent again and then performing the step of precipitating with a poor solvent once or several times.

<Polyimide> The polyimide constituting the liquid crystal aligning agent in the present invention can be prepared by the following methods (1) to (3). Further, a polymer in which a so-called imidation ratio of less than 100%, in which a part of the repeating unit of the polyamic acid is dehydrated and ring-closed, is also suitably used as the liquid crystal aligning agent in the present invention.

Method (1): A method in which a polyamic acid is heated to effect dehydration and ring closure. The reaction temperature in this method is preferably from 60 to 300 ° C, more preferably from 120 to 300 ° C.
250 ° C. When the reaction temperature is lower than 60 ° C., the imidization reaction does not sufficiently proceed, and when the reaction temperature is higher than 250 ° C., the molecular weight of the obtained polyimide may be small.

Method (2): a method in which a polyamic acid is dissolved in an organic solvent, a dehydrating agent and an imidization catalyst are added to the solution, and the solution is heated if necessary. In this method, an acid anhydride such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used as the dehydrating agent. The amount of the dehydrating agent used is preferably 1.6 to 20 mol per 1 mol of the repeating unit of the polyamic acid.
As the imidation catalyst, for example, tertiary amines such as pyridine, collidine, lutidine, and triethylamine can be used. However, it is not limited to these. The amount of the imidation catalyst used is preferably 0.5 to 10 mol per 1 mol of the dehydrating agent used. Examples of the organic solvent used in the imidization reaction include the same organic solvents as those exemplified as the organic solvent used in the synthesis of the polyamic acid. And the reaction temperature of an imidation reaction becomes like this. Preferably it is 0-180 degreeC, More preferably, it is 60-150 degreeC.

Method (3): A method in which tetracarboxylic dianhydride and a diisocyanate compound are mixed and condensed.
Specific examples of the diisocyanate compound used in this method include: an aliphatic diisocyanate compound such as hexamethylene diisocyanate; an alicyclic diisocyanate compound such as cyclohexane diisocyanate; diphenylmethane-4,4'-diisocyanate, diphenylether-4,4'- Diisocyanate, diphenylsulfone-4,4'-diisocyanate, diphenylsulfide-4,4'-diisocyanate, 1,2-diphenylethane-p, p'-diisocyanate, 2,2-diphenylpropane-p, p'-diisocyanate, 2,2-diphenyl-1,1,1,3,3,3-hexafluoropropane-p, p'-diisocyanate, 2,2-diphenylbutane-p, p'-diisocyanate, diphenyl dichloromethane-4,4 ' -Diisocyanates, diphs Fluoroacrylate-4,4'-diisocyanate, benzophenone-4,4'-diisocyanate, and aromatic diisocyanate compounds such as N- phenyl-benzamide 4,4'-diisocyanate. These can be used alone or in combination of two or more.
This method does not require a catalyst, and the reaction temperature is preferably 50 to 200 ° C., more preferably 100 to 1 ° C.
60 ° C. A polyimide can be purified by subjecting the polymer solution thus obtained to the same operation as the method for purifying a polyamic acid.

<Intrinsic Viscosity of Polyamic Acid and Polyimide> The intrinsic viscosity of the polyamic acid and polyimide obtained as described above (measured in N-methyl-2-pyrrolidone at 30 ° C .; the same applies hereinafter) is preferable. 0.05 to 10 dl / g, more preferably 0.05 to 5 d
1 / g.

<Terminal-Modified Polymer> The polyamic acid and polyimide used for the liquid crystal aligning agent for forming the liquid crystal alignment film of the present invention may be terminal-modified polymers. The molecular weight of the terminal-modified polymer is controlled, and the coating characteristics of the liquid crystal aligning agent can be improved without impairing the effects of the present invention. The terminal-modified polymer can be synthesized by adding an acid anhydride, a monoamine compound or a monoisocyanate compound to the reaction system when synthesizing the polyamic acid.

Examples of the acid anhydride to be added to the reaction system for synthesizing the polyamic acid to obtain a terminal-modified polymer include, for example, maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic acid. Anhydride, n-dodecyl succinic anhydride, n-tetradecyl succinic anhydride, n-hexadecyl succinic anhydride and the like can be mentioned. Examples of the monoamine added to the reaction system include, for example, aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-eicosyl Alkylamines such as amines; 3-aminopropylmethyldiethoxysilane, 3- [N-allyl-N- (2-aminoethyl)] aminopropyltrimethoxysilane, N- (2
-Aminoethyl) -3-aminopropylmethyldimethoxysilane, N-[(3-trimethoxysilyl) propyl] diethylenetriamine and the like.
In addition, examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

<Liquid Crystal Alignment Agent> In the liquid crystal alignment film of the present invention, the above-mentioned polyimide and / or polyamic acid is usually used.
It is formed from a liquid crystal alignment agent which is constituted by being dissolved and contained in an organic solvent. Examples of the organic solvent constituting the liquid crystal aligning agent of the present invention include the same organic solvents as those exemplified as the organic solvent used in the synthesis reaction of the polyamic acid. In addition, the same poor solvents as those exemplified as the poor solvent that can be used together in the synthesis reaction of the polyamic acid can be appropriately selected and used in combination.

The solid content concentration in the liquid crystal aligning agent for providing the liquid crystal alignment film of the present invention is selected in consideration of viscosity, volatility and the like, but is preferably in the range of 1 to 10% by weight.
That is, the liquid crystal aligning agent of the present invention is applied to the substrate surface to form a coating film serving as a liquid crystal alignment film. When the solid content concentration is less than 1% by weight, the thickness of the coating film is reduced. It is too small to obtain a good liquid crystal alignment film. Solid concentration of 10
If the amount exceeds 10% by weight, the thickness of the coating film becomes excessively large, making it difficult to obtain a good liquid crystal alignment film, and the viscosity of the liquid crystal alignment agent is increased, so that the coating characteristics are likely to be inferior. The temperature at the time of preparing the liquid crystal alignment agent of the present invention is preferably 0 ° C to 200 ° C.
° C, more preferably 20 ° C to 60 ° C.

The liquid crystal alignment agent for forming the liquid crystal alignment film of the present invention has the following properties from the viewpoint of improving the adhesion to the substrate surface.
It is preferable that a compound having at least one epoxy group in the molecule is contained. Such epoxy group-containing compounds include, for example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1.6 -Hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N, N, N ', N ', -Tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N', N ',-tetraglycidyl-4,4'-
Diaminodiphenylmethane and the like can be mentioned as preferred. These epoxy compounds can be used alone or in combination of two or more. The mixing ratio of these epoxy compounds is preferably 40 parts by weight or less, more preferably 0.1 part by weight, based on 100 parts by weight of the polymer.
1 to 30 parts by weight.

The liquid crystal aligning agent for forming the liquid crystal alignment film of the present invention may contain a functional silane-containing compound from the viewpoint of improving the adhesion to the substrate surface. Such functional silane-containing compounds include, for example, 3
-Aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane,
N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3
-Aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-
Trimethoxysilyl-1,4,7-triazadecane, 10
-Triethoxysilyl-1,4,7-triazadecane, 9
-Trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriacetate Ethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-
Aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane and the like can be mentioned. The compounding ratio of these functional silane-containing compounds is preferably 40 parts by weight or less, more preferably 0.1 to 30 parts by weight, based on 100 parts by weight of the polymer.

<Liquid Crystal Alignment Film and Liquid Crystal Display Element> The liquid crystal alignment film of the present invention can be manufactured, for example, by the following method. (1) A liquid crystal aligning agent for forming a liquid crystal alignment film of the present invention is applied to one surface of a substrate on which a patterned transparent conductive film is provided, for example, by a method such as a roll coater method, a spinner method, or a printing method. Then, a coating film is formed by heating the application surface. As the substrate, for example, a transparent substrate made of glass such as float glass or soda glass; or a plastic such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, or polycarbonate can be used. As the transparent conductive film provided on one surface of a substrate, NESA film (US PPG registered trademark) made of tin oxide (SnO _2), indium oxide - IT consisting of tin oxide (In ₂ O ₃ -SnO ₂₎
An O film or the like can be used. A photo-etching method or a method using a mask in advance is used for patterning these transparent conductive films. In applying the liquid crystal aligning agent, a functional silane-containing compound, a functional titanium-containing compound, etc. are applied in advance to the substrate surface and the surface of the substrate in order to further improve the adhesion between the transparent conductive film and the coating film. You can also. The heating temperature after application of the liquid crystal aligning agent is preferably 80 to 300 ° C, more preferably 120 to 2 ° C.
50 ° C. The liquid crystal aligning agent of the present invention containing a polyamic acid forms a coating film to be an alignment film by removing the organic solvent after coating, but further heats the dehydration ring closure to be further imidized. It can also be a coating film. The thickness of the formed coating film is preferably 0.001 to 1 μm, more preferably 0.01 to 1 μm.
It is 0.5 to 0.5 μm.

(2) A rubbing treatment is performed in which the formed coating film surface is rubbed in a certain direction with a roll around which a cloth made of fibers such as nylon, rayon, cotton or the like is wound. Thereby, the alignment ability of the liquid crystal molecules is imparted to the coating film to form a liquid crystal alignment film. Further, the liquid crystal alignment film formed by the liquid crystal alignment agent of the present invention, for example, as disclosed in JP-A-6-222366 and JP-A-6-281937,
A process of changing the pretilt angle by partially irradiating ultraviolet rays, or Japanese Patent Application Laid-Open No. Hei 5-10754.
No. 4, as described in Japanese Patent Application Laid-Open Publication No. 4 (1999) -1995, a resist film is partially formed on a rubbed liquid crystal alignment film surface, and the rubbing process is performed in a direction different from the previous rubbing process, and then the resist film is removed. By performing a process for changing the liquid crystal alignment ability of the liquid crystal alignment film, the visibility characteristics of the liquid crystal display element can be improved. Further, the liquid crystal display element of the present invention can be obtained, for example, by the following steps following the above steps.

(3) Two substrates on each of which a liquid crystal alignment film is formed as described above are prepared, and the two substrates are opposed to each other with a gap (cell gap) therebetween. A liquid crystal cell is formed by bonding using a sealant, injecting and filling a liquid crystal into the substrate surface and a cell gap defined by the sealant, and sealing the injection hole. Then, by attaching a polarizing plate to the outer surface of the liquid crystal cell, that is, the other surface of each substrate constituting the liquid crystal cell, a liquid crystal display element is obtained. As the sealing agent, for example, an epoxy resin containing a hardening agent and aluminum oxide spheres as a spacer can be used.

Examples of the liquid crystal include nematic liquid crystals, such as Schiff base liquid crystal, azoxy liquid crystal, biphenyl liquid crystal, phenylcyclohexane liquid crystal, ester liquid crystal, terphenyl liquid crystal, biphenylcyclohexane liquid crystal, and pyrimidine liquid crystal. A liquid crystal, a dioxane-based liquid crystal, a bicyclooctane-based liquid crystal, a cubane-based liquid crystal, or the like can be used. In addition, cholesteric liquid crystals such as cholesteryl chloride, cholesteryl nonaate, and cholesteryl carbonate, and chiral agents such as those sold under the trade names "C-15" and "CB-15" (manufactured by Merck & Co.) It can also be used by adding it. Further, as a polarizing plate to be bonded to the outer surface of the liquid crystal cell, a polarizing plate or an H film in which a polarizing film called an H film absorbing iodine is sandwiched by a cellulose acetate protective film while stretching and aligning polyvinyl alcohol. A polarizing plate composed of itself can be mentioned.

[0040]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. The imidation ratio of the liquid crystal alignment film in Examples and Comparative Examples in this specification was obtained by analyzing a coating film on a silicon wafer using FT-IR. The polar term of the surface tension was calculated from the contact angle of water and diiodomethane, ie, methylene iodide, with the liquid crystal alignment film formed on the glass substrate. Further, a voltage holding ratio and a reliability test of a liquid crystal display device manufactured using the alignment film were evaluated by the following methods.

(Imidation ratio) 1 in FT-IR measurement
And absorption near 381cm ^-1 (C-N-C bending vibration = absorption of imide bond), the peak area ratio of the absorption near 1503cm ^-1 (absorption of the amic acid linkages), the imidization ratio by the following formula Calculated. Imidization ratio _{= {α 1 / (α 1} + α 2)} × 100 (%) α1: 1381cm -1 peak area of absorption around [alpha] 2: peak area of absorption around 1503cm ^-1 Incidentally, alpha ₂ is a coating film This is a value obtained by assuming that the absorption near 1503 cm ^-1 of the sample heated on a hot plate at 300 ° C. for 10 minutes is 0, and the peak area is determined.

(Surface tension) Reference "JOURNAL OF"
APPLIED POLYMER SCIENCE
VOL.13, PP.1741-1747 (1969) "
The surface free energy (surface tension) of the liquid crystal alignment film is calculated from the contact angle of pure water and the contact angle of methylene iodide on the liquid crystal alignment film according to the method of DK OWENS et al. I asked. In a system in which a liquid is in contact with the surface of a solid, the relationship between the surface free energy of the liquid, the surface free energy of the solid, and the contact angle is:
It is represented by the following equation (1). _{(1 + cosθ) × γ L} = 2 (γ S d × γ L d) 1/2 +2 (γ S p × γ L p) 1/2 ... (1) γ L: surface free energy gamma _L ^d of the liquid : Dispersion term of surface free energy of liquid γ _L ^p : Polarity term of surface free energy of liquid γ ^S _d : Dispersion term of surface free energy of solid γ _S ^p : Polarity term of surface free energy of solid θ: Contact angle

Under the condition of 20 ° C., for pure water, γ _L = 72.8, γ _L ^d = 21.8, and γ _L ^p = 51.0.
(All units are dyn / cm). For methylene iodide, γ _L = 50.8, γ _L ^d = 49.5 and γ _L
^p = 1.3. By substituting these values into Equation (1), Equation (2) below is obtained in the case of pure water, and Equation (3) below is obtained in the case of methylene iodide. Here, θ ₁ and θ ₂ are the contact angles of pure water and methylene iodide, respectively. _{(1 + cosθ 1) × 72.8} = 2 (γ S d × 21.8) 1/2 +2 (γ S p × 51.0) 1/2 ... (2) (1 + cosθ 2) × 50.8 = 2 (γ _S ^d × 49.5) ^1/2 +2 (γ _S ^p × 1.3) ^1/2 ... (3) Therefore, the measured values of the contact angle can be calculated using the above formulas (2) and (3). substituting obtains the gamma _S ^d and gamma _S ^p from the simultaneous equations to determine the surface free energy gamma _S of film by further following formula (4). ^{_{γ S = γ S d + γ}} S p ... (4) contact angle, contact angle measuring device "CA-A type" using (Kyowa Interface Science Co., Ltd.), film of water or methylene iodide And the contact angle after 1 minute was measured.

(Voltage holding ratio) The liquid crystal display device was left in a high-temperature bath at 60 ° C. for 10 minutes, and the voltage holding ratio (frame period of 16.7 ms) of the liquid crystal display device after standing was set to “VHR−
1 "(manufactured by Toyo Corporation). (Reliability test) A liquid crystal display element was placed in a 70 ° C. constant temperature bath, and a drive waveform generator “Function / arbi” was used.
TRY WAVEFORM GENERATOR "
(Hewlett Packard) for 24 hours
After the continuous driving, the presence or absence of contrast unevenness and display defect is checked.

Synthesis Example 1 224.17 g (1 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride and 108.14 g (1 mol) of p-phenylenediamine as diamine compound were added to N -Methyl-2-pyrrolidone was dissolved in 4500 g and reacted at 60 ° C. for 6 hours. Then, the reaction solution was poured into a large excess of methyl alcohol to precipitate a reaction product. Thereafter, the resultant is washed with methyl alcohol and dried under reduced pressure at 40 ° C. for 15 hours to obtain a polyamic acid having a logarithmic viscosity of 0.90 dl / g and an imidation ratio of 0% (this is referred to as “polyamic acid (A-1)”).
410 g).

Synthesis Example 2 30 g of the polyamic acid obtained in Synthesis Example 1 was dissolved in 570 g of N-methyl-2-pyrrolidone.
4 g and 18.1 g of acetic anhydride were added thereto, followed by dehydration and ring closure at 110 ° C. for 4 hours. Precipitation, washing, and reduced pressure were performed in the same manner as described above, and the logarithmic viscosity was 0.85 dl / g, and the imidization ratio was 100%.
17.5 g of this polyimide (hereinafter referred to as "polyimide (B-1)") was obtained.

Synthesis Example 3 Synthesis Example 1 was repeated except that the diamine was changed to 198.27 g (1 mol) of 4,4′-diaminodiphenylmethane.
A polyamic acid (hereinafter, referred to as "polyamic acid (A-2)") was obtained in the same manner as in Synthesis Example 1, and an imidization reaction was further performed using the same to obtain a logarithmic viscosity of 1.16 dl. / G of polyimide (hereinafter referred to as "polyimide (B-2)") (22.2 g) was obtained. Synthesis Example 4 The procedure of Synthesis Example 1 was repeated except that the tetracarboxylic dianhydride was changed to 196.12 g (1 mol) of cyclobutanetetracarboxylic dianhydride. -3) ") 42
0 g was obtained. Synthesis Example 5 Synthesis Example 1 was repeated except that the tetracarboxylic dianhydride was changed to 109.06 g (0.5 mol) of pyromellitic anhydride and 98.06 g (0.5 mol) of cyclobutanetetracarboxylic dianhydride. Polyamic acid (this is referred to as "polyamic acid (A-4)") 485 in the same manner as in Example 1.
g was obtained.

Synthesis Example 6 Synthesis Example 1 was repeated except that the diamine was changed to 54.7 g (0.5 mol) of p-phenylenediamine and 99.14 g (0.5 mol) of 4,4′-diaminodiphenylmethane. A polyamic acid (hereinafter referred to as “polyamic acid (A-5)”) was obtained in the same manner as in Example 1, and an imidation reaction was carried out using this in the same manner as in Synthesis Example 2 to give a logarithmic viscosity of 1.
08 dl / g of polyimide (this is referred to as "polyimide (B-
3) ") was obtained. Synthesis Example 7 In Synthesis Example 1, 109.06 g (0.5 mol) of pyromellitic anhydride and 98.06 g (0.5 mol) of cyclobutanetetracarboxylic dianhydride were used as the tetracarboxylic dianhydride.
Mol) and the diamine is p-phenylenediamine 54.
Polyamic acid (this was referred to as "polyamic acid (A-6)") in the same manner as in Synthesis Example 1 except that 7 g (0.5 mol) and 99.14 g (0.5 mol) of 4,4'-diaminodiphenylmethane were used. And).

Synthesis Example 8 In Synthesis Example 1, tetracarboxylic dianhydride was changed to 1,2,
4,5-cyclohexanetetracarboxylic dianhydride 22
The amount of the diamine was 99.14 g (0.5 mol) and 2,2-bis [4- (4-aminophenoxy) phenyl] propane (205.26 g). 385 g of a polyamic acid (hereinafter referred to as “polyamic acid (A-7)”) was obtained in the same manner as in Synthesis Example 1 except that the amount was changed to 0.5 mol. Synthesis Example 9 In Synthesis Example 1, tetracarboxylic dianhydride was changed to 1,2,
4,5-cyclohexanetetracarboxylic dianhydride 22
4.00 g (1.0 mol), the diamine was 4,4'-diaminodiphenylmethane 158.62 g (0.8 mol) and 2,2-bis [4- (4-aminophenoxy) phenyl] propane 82.10 g 406 g of a polyamic acid (hereinafter referred to as “polyamic acid (A-8)”) was obtained in the same manner as in Synthesis Example 1 except that the amount was 0.2 mol.

Synthesis Example 10 As the tetracarboxylic dianhydride, 224.17 g of 2,3,5-tricarboxycyclopentylacetic dianhydride (0.5%)
Mol) 1,3,3a, 4,5,9b-Hexahydro-5-
157.14 g (0.5 mol) of methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione and p-phenylenediamine as a diamine compound 94.62 g (0.875 mol), 2,2-ditrifluoromethyl-4,4-diaminobiphenyl 32.02 g (0.1 mol), 3,6-bis (4-aminobenzoyloxy) cholestane 6.43 g
(0.01 mol), 4.04 g (0.015 mol) of 4-aminophenyloctadecyl ether was added to N-methyl-2-
It was dissolved in 4500 g of pyrrolidone and reacted at 60 ° C. for 6 hours. Then, the reaction solution was poured into a large excess of methyl alcohol to precipitate a reaction product. Thereafter, it is washed with methyl alcohol and dried under reduced pressure at 40 ° C. for 15 hours to obtain a logarithmic viscosity of 0.87 dl / g and an imidation ratio of 0%.
Of polyamic acid was obtained. 30 g of the obtained polyamic acid was dissolved in 570 g of N-methyl-2-pyrrolidone, 23.4 g of pyridine and 18.1 g of acetic anhydride were added, and the resultant was subjected to dehydration and ring closure at 110 ° C. for 4 hours. The pressure was reduced and the logarithmic viscosity was 0.80 dl /
g, 17.5 g of a polyimide having an imidation ratio of 100% (this is referred to as "polyimide (B-4)").

Synthesis Example 11 224.17 g (0.5%) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as tetracarboxylic dianhydride
Mol) 1,3,3a, 4,5,9b-Hexahydro-5-
157.14 g (0.5 mol) of methyl-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione and p-phenylenediamine as a diamine compound 94.62 g (0.875 mol), bisaminopropyltetramethyldisiloxane 2
4.85 g (0.1 mol), 6.43 g (0.01 mol) of 3,6-bis (4-aminobenzoyloxy) cholestane, 4-aminophenyloctadecyl ether 4.0
4 g (0.015 mol) was dissolved in 4500 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours. Then, the reaction solution was poured into a large excess of methyl alcohol to precipitate a reaction product. Thereafter, by washing with methyl alcohol and drying under reduced pressure at 40 ° C. for 15 hours,
370 g of a polyamic acid having a logarithmic viscosity of 0.82 dl / g and an imidation ratio of 0% was obtained. 30 g of the obtained polyamic acid
Was dissolved in 570 g of N-methyl-2-pyrrolidone, 23.4 g of pyridine and 18.1 g of acetic anhydride were added, and 11
After dehydration and ring closure at 0 ° C. for 4 hours, precipitation, washing, and reduced pressure were performed in the same manner as described above, and a polyimide having an intrinsic viscosity of 0.77 dl / g and an imidation ratio of 100% (this was referred to as “polyimide (B-
5) ") 18.5 g was obtained.

Synthesis Example 12 In Synthesis Example 1, 196.12 g (1.0 mol) of cyclobutanetetracarboxylic dianhydride was used as the tetracarboxylic dianhydride, and 20.2 g (1.0 mol) of 4,4-diaminodiphenyl ether was used as the diamine. ) Except that polyamic acid (this was referred to as “polyamic acid (A-
485 g). Synthesis Example 13 In Synthesis Example 1, 196.12 g (1.0 mol) of cyclobutanetetracarboxylic dianhydride was used as the tetracarboxylic dianhydride, and 212 g (1.0 mol) of the diamine was used as 2,2-dimethyl-4,4-diaminobiphenyl. Synthesis Example 1 except that
475 g of a polyamic acid (hereinafter, referred to as “polyamic acid (A-10)”) was obtained in the same manner as described above.

Synthesis Example 14 In Synthesis Example 5, 112.09 g (0.5 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride as a tetracarboxylic dianhydride and 109.000 mmol of pyromellitic anhydride were used. 06 g (0.5 mol), 2,2-bis [4- (4-aminophenoxy) as a diamine compound
Phenyl] propane was used in the same manner as in Synthesis Example 1 except that 410.52 g (1.0 mol) was used, and the logarithmic viscosity was 0.83 d.
l / g of polyamic acid (this is referred to as "polyamic acid (A
-11) "), and further subjected to an imidation reaction in the same manner as in Synthesis Example 2 to obtain a polyimide having a logarithmic viscosity of 1.28 dl / g (this was referred to as" polyimide (B-6) "). To do).

Synthesis Example 15 218.12 g (1 mol) of pyromellitic anhydride as tetracarboxylic dianhydride and p as diamine compound
-Logarithmic viscosity was 1.95 d in the same manner as in Synthesis Example 1 except that 108.14 g (1 mol) of phenylenediamine was used.
l / g of polyamic acid (this is referred to as "polyamic acid (A
-12 g) was obtained. Synthesis Example 16 A polyamic acid having an logarithmic viscosity of 0.9 dl / g was prepared in the same manner as in Synthesis Example 5 except that the diamine was changed to 20.2 g (1.0 mol) of 4,4-diaminodiphenyl ether. 380 g of “polyamic acid (A-13)” was obtained.

Synthesis Example 17 1,3,3a, 4,5,9 as tetracarboxylic dianhydride
b-Hexahydro-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-
30.3 g (1 mol) of 1,3-dione, 97.2 g (0.9 mol) of p-phenylenediamine as a diamine and 13.4 g of 1-hexadecanoxy-2,4-diaminobenzene.
A polyamic acid was obtained in the same manner as in Synthesis Example 1 except that 8 g (0.1 mol) was used.
A polyimide having an imidation ratio of 100% and a logarithmic viscosity of 0.43 dl / g (this is referred to as "polyimide (B-7)") 2.
95 g were obtained.

Example 1 The polyamic acid (A-1) obtained in Synthesis Example 1 was converted to N-methyl-2-pyrrolidone / γ-butyrolactone (1/9).
Dissolved in a mixed solvent to make a solution with a solid concentration of 4% by weight,
This solution was filtered using a filter having a pore size of 1 μm to prepare a liquid crystal aligning agent. The liquid crystal aligning agent was applied on a silicon wafer, dried on a hot plate at 180 ° C. for 10 minutes, and subjected to FT-IR analysis. As a result, the imidization ratio was about 95%. The polarity term of the surface tension calculated from the contact angle of water and diiodomethane with the liquid crystal alignment film formed on the glass substrate was 12 dyn / cm. Further, the above liquid crystal aligning agent was applied to the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film using a printing machine for coating a liquid crystal aligning film.
After drying for 0 minutes, a film having a dry average film thickness of 500 Å was formed. A rubbing machine having a roll in which a rayon cloth was wound around the coating film was subjected to a rubbing treatment at a roll rotation speed of 400 rpm, a stage moving speed of 3 cm / sec, and a hair foot pushing length of 0.4 mm. After immersing the substrate coated with the alignment film in isopropyl alcohol for 1 minute, both substrates were dried on a hot plate at 100 ° C. for 5 minutes. Next, at each outer edge of the pair of rubbed liquid crystal sandwiching substrates having a liquid crystal alignment film,
After an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm was applied, a pair of liquid crystal sandwiching substrates were overlapped with each other so that the surfaces of the liquid crystal alignment films faced each other, and pressed to cure the adhesive. Next, a nematic liquid crystal (MLC-6221 manufactured by Merck) is filled between the pair of substrates from the liquid crystal injection port, and then the liquid crystal injection port is sealed with an acrylic photocuring adhesive. A polarizing plate was laminated to produce a liquid crystal display device. The voltage holding ratio shows a high value of 99%,
After the reliability test, no contrast unevenness or display defect was observed.

Examples 2 to 20 and Comparative Examples 1 to 5 Using the polyamic acid and / or polyimide obtained in Synthesis Examples 2 to 17 and changing the drying temperature of the liquid crystal alignment film to imidize the liquid crystal alignment film A liquid crystal display device was manufactured in the same manner as in Example 1 except that the polarities of the ratio and the surface tension were changed. Examples 13, 14, 1
7, 18, 19, 20 and Comparative Examples 4 and 5, the polyamic acid and the polyimide were polyamic acids:
Polyimide was used at a ratio of 4: 1 (weight ratio). Table 1 shows the results.

[0058]

[Table 1]

[0059]

According to the liquid crystal alignment film of the present invention, when a liquid crystal display element is used, a display element exhibiting a high voltage holding ratio and having excellent reliability without contrast unevenness and display defects can be produced. The liquid crystal display device having the liquid crystal alignment film of the present invention can be suitably used for TN type and STN type liquid crystal display devices.
SH (Super Homeotropic) type, IP
It can be suitably used for an S (In-Plane Switching) type, ferroelectric and antiferroelectric liquid crystal display device and the like. Further, the liquid crystal display device having the liquid crystal alignment film of the present invention can be effectively used in various devices, and is used for display devices such as desktop calculators, watches, clocks, coefficient display plates, word processors, personal computers, and liquid crystal televisions. .

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme Court ゛ (Reference) C08L 63:00) C08L 63:00) (72) Inventor Masaki Obi 2-11-24 Tsukiji, Chuo-ku, Tokyo No. F-term (reference) in JSR Co., Ltd. TA22 TB01 TB02 UA022 UA032 UA041 UA042 UA051 UA052 UA061 UA081 UA082 UA121 UA122 UA131 UA132 UA141 UA142 UA151 UA152 UA241 UA261 UA262 UA511 UA621 UA761 UA762 UB011 UB012 UB021 UB061 UB062 UB121 UB122 UB131 UB132 UB151 UB152 UB162 UB171 UB241 UB271 UB281 UB282 UB301 UB302 UB312 UB351 XA13 YA05 YA06 YA07 YA08 ZA11 ZA12 ZB23

Claims (6)

[Claims] 1. A liquid crystal alignment film comprising (a) a polymer having an imide bonding unit or a polymer having both an amic acid bonding unit and an imide bonding unit, wherein the imide bonding unit and the amic acid The percentage ratio of the number of imide bond units to the total number of acid bond units is 3
(B) a polar term of surface tension of 10 dyn / cm or more. 2. A polymer obtained by reacting a tetracarboxylic dianhydride with a diamine, wherein the tetracarboxylic dianhydride is an aliphatic and / or alicyclic tetracarboxylic dianhydride. The liquid crystal alignment film according to claim 1, which is a substance. 3. The liquid crystal alignment film according to claim 1, wherein the percentage of the number of imide bond units to the total number of imide bond units and amic acid bond units in the polymer is 30% to 70%. 4. The method of claim 1, wherein the tetracarboxylic acid is butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid. Acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1 , 2,3,4-tetramethyl-
1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3 , 3 ', 4,4'-Dicyclohexyltetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 3,5,6-tricarboxynorbornane-2-acetic dianhydride, 2, 3,4,5-tetrahydrofurantetracarboxylic dianhydride, bicyclo [2.2.2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride and cis-3,7- The liquid crystal alignment film according to claim 1, wherein the liquid crystal alignment film is at least one selected from dibutylcycloocta-1,5-diene-1,2,5,6-tetracarboxylic dianhydride. 5. The liquid crystal alignment film according to claim 1, comprising a compound having at least one epoxy group in a molecule. 6. A liquid crystal display device comprising the liquid crystal alignment film according to claim 1.