KR100850242B1 - Liquid crystal aligning agent, liquid crystal aligning film and liquid crystal display device - Google Patents

Abstract

An object of the present invention is to provide an alignment film which can provide a liquid crystal display device excellent in high reliability, high liquid crystal alignment property, and high rubbing resistance, and which can be easily peeled off for substrate regeneration.

A liquid crystal aligning film comprising a polymer or mixture thereof having at least one of an imide bond unit and an amic acid bond unit formed by a reaction of tetracarboxylic dianhydride and diamine. The tetracarboxylic dianhydride for the polymer or mixtures thereof is 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 3,3 ', 4,4'-dicyclohexyltetracarboxylic acid 2 Anhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 3,5,6-tricarboxynobornane-2-acetic acid dianhydride, 2,3,4,5-tetrahydrofurantetetracarboxylic acid 2 Anhydride, bicyclo [2.2.2] -octo-7-ene-2,3,5,6-tetracarboxylic dianhydride, 1,3,3a, 4,5,9b-hexahydro-8-methyl- At least three selected from the group consisting of 5- (tetrahydro-2,5-dioxo-3-furanyl) naphtho [1,2-c] furan-1,3-dione and pyromellitic dianhydride And the diamine is p-phenylenediamine, bisaminopropyltetramethyldisiloxane, 4,4'-diaminodiphenylmethane, 2,2'-dimethyl-4,4'-diaminobiphenyl and 3 At least one selected from the group consisting of 6-bis (4-aminobenzoyloxy) cholestane It contains the three species.

Description

Liquid crystal aligning agent, liquid crystal aligning film and liquid crystal display device {LIQUID CRYSTAL ALIGNING AGENT, LIQUID CRYSTAL ALIGNING FILM AND LIQUID CRYSTAL DISPLAY DEVICE}

This invention relates to a liquid crystal aligning agent, a liquid crystal aligning film, and a liquid crystal display element. In detail, it is excellent in reliability, low afterimage, rubbing resistance, and liquid crystal orientation, and is particularly applied to a large substrate, and can be easily peeled off by a commercially available liquid-based or organic liquid crystal alignment film stripping liquid for regenerating the substrate. A liquid crystal aligning agent for providing a liquid crystal aligning film, a liquid crystal aligning film thereof, and the liquid crystal display element using the same.

Conventionally, a layer of nematic liquid crystals having positive dielectric anisotropy is formed between two substrates on which a liquid crystal alignment film is formed on the surface via a transparent conductive film to form a sandwich cell, and the long axis of the liquid crystal molecules is one substrate. A TN type liquid crystal display device having a TN (Twisted Nematic) type liquid crystal cell which is twisted continuously by 90 degrees from the side toward the other substrate is known.

Furthermore, the addition of a chiral agent achieves a state in which the major axis of the liquid crystal molecules is twisted continuously over 180 degrees between the substrates, and the STN (Super Twisted Nematic) type liquid crystal display device using the birefringence effect generated thereby. Also exists. In recent years, nematic liquid crystal layers or homeotropic liquid crystal layers having negative dielectric anisotropy and opposing substrates form cholesteric liquid crystal layers in which a spiral axis is parallel to a substrate normal, and these liquid crystal layers The guest-host reflection type liquid crystal display element which added the pigment | dye was also developed. Here, as a material of the liquid crystal aligning film which comprises a liquid crystal display element, polyimide, polyamide, polyester, etc. are known conventionally. In particular, polyimides are used in many liquid crystal display devices because of their excellent heat resistance, affinity with liquid crystals, mechanical strength, and the like.

However, in recent years, liquid crystal display devices have also made remarkable developments as high-performance display devices in terms of size, light weight, low power consumption, and the like, and accordingly, the required performance of liquid crystal alignment films has become increasingly strict. In particular, there has been a strict demand for process improvement and low cost in accordance with the enlargement of substrates. However, a liquid crystal aligning film made of a polyamic acid, which is a precursor of a polyimide known in the art, or an imide-based polymer having a structure obtained by dehydrating and ring-closing a polyimide is a substrate for realizing its high reliability, high alignment control force, and high rubbing resistance. High adhesiveness and applicability are given. As a result, even when attempting to regenerate a large substrate in order to realize low cost, and trying to peel an alignment film using commercial water-based and organic type liquid crystal aligning film peeling liquid, it could not peel enough. On the other hand, the alignment film which can be easily peeled off using a commercial liquid crystal aligning film peeling liquid has a problem that reliability, orientation control force, and rubbing resistance fall.

 SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal aligning agent which provides good liquid crystal alignment film that can be easily peeled off with a commercial aqueous and organic peeling solution while exhibiting good reliability, orientation characteristics and rubbing resistance.

Another object of the present invention is to provide a liquid crystal alignment film having excellent various performances as described above.

Another object of the present invention is to provide a liquid crystal display device comprising the liquid crystal alignment film of the present invention.

Still other objects and advantages of the present invention will become apparent from the following description.

According to the present invention, the object and advantages of the present invention are firstly a polymer or mixture thereof having at least one of an imide linkage unit and an amic acid linkage unit formed by the reaction of tetracarboxylic dianhydride and diamine. As said liquid crystal aligning agent, the said tetracarboxylic dianhydride with respect to the said polymer or its mixture is a 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 3,3 ', 4,4'-dicyclo Hexyl tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetate dianhydride, 3,5,6-tricarboxynobornane-2-acetic acid dianhydride, 2,3,4,5-tetrahydro Furantetracarboxylic dianhydride, bicyclo [2.2.2] -octo-7-ene-2,3,5,6-tetracarboxylic dianhydride, 1,3,3a, 4,5,9b-hexa In the group consisting of hydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) naphtho [1,2-c] furan-1,3-dione and pyromellitic dianhydride Three kinds of paper chosen Phase, and the diamine is p-phenylenediamine, bisaminopropyltetramethyldisiloxane, 4,4'-diaminodiphenylmethane, 2,2'-dimethyl-4,4'-diaminobiphenyl And 3,6-bis (4-aminobenzoyloxy) cholesterane, and at least three kinds selected from the group consisting of.

According to the present invention, the above objects and advantages of the present invention are achieved by a liquid crystal alignment film formed of the liquid crystal alignment agent of the present invention.

According to the present invention, the above objects and advantages of the present invention are thirdly achieved by a liquid crystal display device comprising the liquid crystal alignment film of the present invention.

Still other objects and advantages of the present invention will become apparent from the following description.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail. The liquid crystal aligning film of this invention is normally formed by apply | coating the liquid crystal aligning agent of this invention on a transparent electrode board | substrate, and then drying (usually heat-drying), and using it after performing the orientation process on the film surface, such as rubbing. do. The liquid crystal aligning agent of this invention consists of a polymer which has at least one of the imide bond unit and the amic acid bond unit formed by reaction of tetracarboxylic dianhydride and diamine, or its mixture. When the liquid crystal aligning agent contains both bonding units, a mixture of polyimide and polyamic acid may be contained, or a polymer having both an imide bond unit and an amide bond unit may be contained. In this polymer, the imide bond unit and the amide bond unit may be contained randomly or in any one of the block phases.

The liquid crystal aligning film of the present invention may be heat-dried at the time of applying and drying the liquid crystal aligning agent on a substrate to dehydrate and close the amide bonding unit in the liquid crystal aligning agent to form an imide bonding unit. .

<Polyamic acid>

The polyamic acid used by this invention is obtained by ring-opening polyaddition of tetracarboxylic dianhydride and a diamine compound.

[Tetracarboxylic dianhydride]

As tetracarboxylic dianhydride, 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 3,3 ', 4,4'- dicyclohexyl tetracarboxylic dianhydride, 2,3,5 -Tricarboxycyclopentyl acetate dianhydride, 3,5,6-tricarboxynobornane-2-acetic acid dianhydride, 2,3,4,5-tetrahydrofurante tetracarboxylic dianhydride, bicyclo [2.2. 2] -octo-7-ene-2,3,5,6-tetracarboxylic dianhydride, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2 , 5-dioxo-3-furanyl) naphtho [1,2-c] furan-1,3-dione and pyromellitic dianhydride are used.

As tetracarboxylic dianhydride, it is necessary to use it combining 3 or more types from the said 8 types of compounds. By using three or more types in combination, it becomes possible to peel a liquid crystal aligning film from a board | substrate easily with a peeling liquid as needed. It is preferable to contain pyromellitic dianhydride in 3 or more types of combination, and it is especially preferable to contain pyromellitic dianhydride in 30 mol% or more with respect to 100 mol% of total tetracarboxylic dianhydrides.

The polyamic acid used by this invention can contain other tetracarboxylic dianhydride as needed in addition to the said eight types of compounds as tetracarboxylic dianhydride.

As such other tetracarboxylic dianhydride, butane tetracarboxylic dianhydride, a 1, 2- dimethyl- 1, 2, 3, 4- cyclobutane tetracarboxylic 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 acid 2 Anhydride, 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] -furan-1,3-dione, 1,3,3a, 4,5,9b-hexahydro-7-methyl-5 (tetrahydro-2,5-dioxo-3-furanyl)- I Earth [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-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-dione, 5- (2,5-dioxotetrahydrofural) -3- Aliphatic and alicyclic tetracarboxylic dianhydrides such as methyl-3-cyclohexene-1,2-dicarboxylic dianhydride and compounds represented by the following formulas (I) and (II);

(In formula, R <^1> and R <^4> represents the bivalent organic group which has an aromatic ring, R <^2> and R <^3> represents a hydrogen atom or an alkyl group, and ^two or more R <^2> and R <^3> may be same or different, respectively. )

3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-biphenylsulfontetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarb Acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ', 4,4'-biphenylethertetracarboxylic dianhydride, 3,3', 4,4 ' -Dimethyldiphenylsilanetetracarboxylic dianhydride, 3,3 ', 4,4'-tetraphenylsilanetetracarboxylic dianhydride, 1,2,3,4-furtetracarboxylic dianhydride, 4, 4'-bis (3,4-dicarboxyphenoxy) diphenylsulfide dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride, 4,4'-bis ( 3,4-dicarboxyphenoxy) diphenylpropane dianhydride, 3,3 ', 4,4'-perfluoroisopropylidenediphthalic dianhydride, 3,3', 4,4'-biphenyltetracarb Acid dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride, m-phenylene-bis (triphenylphthalic acid) dianhydride, non (Triphenylphthalic acid) -4,4'- diphenyl ether dianhydride, bis (triphenylphthalic acid) -4,4'- diphenylmethane dianhydride, ethylene glycol -bis (anhydro trimellitate), propylene glycol- Bis (anhydrotrimerate), 1,4-butanediol-bis (anhydrotrimerate), 1,6-hexanediol-bis (anhydrotrimerate), 1,8-octanediol-bis (an Aromatic tetracarboxylic acids 2 such as hydrotrimerate), 2,2-bis (4-hydroxyphenyl) propane-bis (anhydrotrimerate), and compounds represented by the following formulas (1) to (4): Anhydrides are mentioned. These other tetracarboxylic dianhydrides are used individually by 1 type or in combination of 2 or more types.

These other tetracarboxylic dianhydrides are preferably 50 to 0.1 mol%, more preferably 30 to 0.1 mol% with respect to all the tetracarboxylic dianhydrides with respect to the polymer or a mixture thereof used in the present invention. Especially preferably, it is used at 25-0.1 mol%.

[Diamine Compound]

Examples of the diamine compound include p-phenylenediamine, bisaminopropyltetramethyldisiloxane, 4,4'-diaminodiphenylmethane, 2,2'-dimethyl-4,4'-diaminobiphenyl and 3,6 -Bis (4-aminobenzoyloxy) cholestane is used. As a diamine, it is necessary to use it combining 3 or more types out of these 5 types of diamine.

By using three or more types in combination, it becomes possible to peel a liquid crystal aligning film from a board | substrate easily with a peeling liquid as needed.

The polyamic acid used by this invention can contain other diamine compounds as needed in addition to the said 5 types of compounds as a diamine compound.

As such another diamine compound, m-phenylenediamine, 4,4'- diamino diphenyl ethane, 4,4'- diamino diphenyl sulfide, 4,4'- diamino diphenyl sulfone, 3 , 3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diaminobenzanilide, 4,4'-diaminodiphenylether, 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, 3,4'-diaminodiphenylether, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 2 , 2'-bis [4- (4-aminophenoxy) phenyl] propane, 2,2'-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- Minophenyl) -10-hydroanthracene, 2,7-diaminofluorene, 9,9-bis (4-aminophenyl) fluorene, 4,4'-methylene-bis (2-chloroaniline), 2,2 '-Ditolylfluoromethyl-4,4'-diamino diphenyl, 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-trifluoromethylphenoxy) phenyl] hexafluoropropane, 4, 4'-diamino-2,2'-bis (trifluoromethyl) biphenyl, 4,4'-bis [(4-amino-2-trifluoromethyl) phenoxy] -octafluorobiphenyl Aromatic diamines; p-xylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, heptamethylenediamine, 1,4-diaminocyclohexane , Isophoronediamine, tetrahydrodisclopentadienylenediamine, hexahydro-4,7-methanoindanylenedimethylenediamine, tricyclo [6,2,1,0 ^2.7 ] -undecylenedimethyldiamine, 4,4 ' Aliphatic and alicyclic diamines such as -methylenebis (cyclohexylamine);

Monosubstituted phenylenediamines represented by the following formula (III); Diaminoorganosiloxane represented by the following formula (IV), except for bisaminopropyltetramethyldisiloxane;

(Wherein X represents a divalent organic group selected from -O-, -COO-, -OCO-, -NHCO-, -CONH-, and -CO-, and R ⁵ represents a steroid skeleton or a trifluoromethyl group R <^9> represents a C1-C12 hydrocarbon group, two or more R <^9> may be same or different, respectively, p is an integer of 1-3 and q is an integer of 1-20. )

The compound etc. which are represented by following formula (5)-(8) are mentioned. These diamine compounds can be used individually or in combination of 2 or more types.

(In formula, y is an integer of 2-12, z is an integer of 1-5.)

These other diamine compounds are preferably 80 to 0.1 mol%, more preferably 60 to 0.1 mol%, particularly preferably 50 to the total diamine compound with respect to the polymer or mixture thereof used in the present invention. 0.1 mol% is used.

The use ratio of the tetracarboxylic dianhydride and the diamine compound provided for the synthesis reaction of the polyamic acid is 0.2 to 2 equivalents of the acid anhydride group contained in the tetracarboxylic dianhydride relative to 1 equivalent of the amino group contained in the diamine compound. The ratio which becomes is preferable, More preferably, it is the ratio which becomes 0.3-1.4 equivalent. In the case where the ratio of the acid anhydride group contained in tetracarboxylic dianhydride is less than 0.2 equivalent or more than 2 equivalent, the molecular weight of the polymer obtained becomes too small and the applicability | paintability of a liquid crystal aligning agent will become inferior There is a case.

The polyamic acid which comprises the liquid crystal aligning agent of this invention is synthesize | combined by reaction of the said tetracarboxylic dianhydride and the said diamine compound. The synthesis reaction of the polyamic acid is usually carried out in an organic solvent under a temperature condition of 0 to 150 ° C, preferably 0 to 100 ° C. When reaction temperature is 0 degrees C or less, the solubility to a solvent of a compound may fall, and when it exceeds 150 degreeC, the molecular weight of the polymer obtained may fall.

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 produced by the reaction. For example, γ-butyrolactone and N-methyl 2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, tetramethylurea, hexamethylphosphoryltriamide, 1,3-dimethyl-2-imidazolidinone Aprotic polar solvents such as these; and phenol solvents such as m-cresol, xylenol, phenol, and halogenated phenol.                     

The amount (A) of the organic solvent is preferably an amount such that the total amount (B) of tetracarboxylic dianhydride and the diamine compound as the reaction raw material is 0.1 to 30% by weight based on the total amount (A + B) of the reaction solution. .

Moreover, alcohol, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, etc. which are poor solvents of polyamic acid can be used together with the said organic solvent in the range which does not precipitate polyamic acid which produces | generates. . As a specific example of such a poor solvent, 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, di Ethylene 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, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, ethylene glycol ethyl ether acetate, 4-hydroxy-4-methyl-2-pentanone, 2-hydrate Ethyl oxypropionate, ethyl lactate, methyl lactate, butyl lactate, ethyl ethoxy acetate, ethyl hydroxy acetate, methyl 2-hydroxy-3-methylbutane, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, 3 Methyl 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-dichlorobenzene, hexane, heptane, octane, benzene, toluene, xylene, etc. The can. These can be used individually by 1 type or in combination of 2 or more types.

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

<Polyimide>

The polyimide which comprises the liquid crystal aligning agent of this invention can be prepared by the following method (1)-(2). In addition, a polymer having a so-called imidation ratio of less than 100% in which some of the repeating units of the polyamic acid are dehydrated and closed is also suitably used for the liquid crystal aligning agent of the present invention.

Method (1): The method of heating and dehydrating a polyamic acid for ring closure.

Reaction temperature in this method becomes like this. Preferably it is 60-300 degreeC, More preferably, it is 120-250 degreeC. If reaction temperature is less than 60 degreeC, the imidation reaction may not fully advance, but when reaction temperature exceeds 250 degreeC, the molecular weight of the polyimide obtained may become small.

Method (2): A method of dissolving a polyamic acid in an organic solvent, adding a dehydrating agent and an imidization catalyst in this solution, and heating as needed.

In this method, for example, acid anhydrides such as acetic anhydride, propionic anhydride and trifluoroacetic anhydride can be used. It is preferable that the usage-amount of a dehydrating agent shall be 1.6-20 mol with respect to 1 mol of repeating units of a polyamic acid. As the imidization catalyst, tertiary amines such as pyridine, collidine, lutidine, triethylamine, and the like can be used, but are not limited thereto. It is preferable that the usage-amount of an imidation catalyst shall be 0.5-10 mol with respect to 1 mol of dehydrating agents to be used. Moreover, as an organic solvent used for imidation reaction, the thing similar to the organic solvent illustrated as what is used for the synthesis | combination of a polyamic acid is mentioned. And reaction temperature of imidation reaction becomes like this. Preferably it is 0-180 degreeC, More preferably, it is 60-150 degreeC.

<Intrinsic Viscosity of Polyamic Acid and Polyimide>

The intrinsic viscosity of the polyamic acid and the polyimide obtained as described above (measured in N-methyl-2-pyrrolidone at 30 ° C., which is the same below) is preferably 0.05 to 10 dl / g, more preferably. Preferably it is 0.05-5d1 / g.

<Terminal Formula Polymer>

The terminal-type polymer may be sufficient as the polyamic acid and polyimide used for the liquid crystal aligning agent which forms the liquid crystal aligning film of this invention. The molecular weight of this terminally modified polymer can be adjusted to improve the coating properties and the like of the liquid crystal aligning agent 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.

As an acid anhydride added to the reaction system at the time of synthesize | combining a polyamic acid, in order to obtain a terminal type polymer, a maleic anhydride, a phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecyl succinic anhydride, n Tetradecyl succinic anhydride, n-hexadecyl succinic anhydride, etc. are mentioned. As the monoamine added to the reaction system, 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 alkylamines such as n-eicosylamine; 3-aminopropylmethyldiethoxysilane, 3- [N-allyl-N- (2-aminoethyl)] aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N-[(3-trimethoxysilyl) propyl] diethylenetriamine, etc. are mentioned. Moreover, as a monoisocyanate compound, phenyl isocyanate, naphthyl isocyanate, etc. are mentioned, for example.

<Liquid crystal aligning agent>

In the liquid crystal aligning film of this invention, the said polyimide and / or polyamic acid are normally formed with the liquid crystal aligning agent comprised by melt-containing in an organic solvent.

As an organic solvent which comprises the liquid crystal aligning agent of this invention, the thing similar to the solvent illustrated as what is used for the synthesis reaction of polyamic acid is mentioned. Moreover, the poor solvent illustrated as what can be used together at the time of the synthesis reaction of a polyamic acid can also be selected suitably, and can be used together.                     

Although solid content concentration in the liquid crystal aligning agent which gives the liquid crystal aligning film of this invention is selected in consideration of viscosity, volatility, etc., Preferably it becomes the range of 1 to 10 weight%. That is, although the liquid crystal aligning agent of this invention is apply | coated to the board | substrate surface, and the coating film which becomes a liquid crystal aligning film is formed, when solid content concentration is less than 1 weight%, the film thickness of this coating film becomes small and it is difficult to obtain a favorable liquid crystal aligning film. When the solid content concentration exceeds 10% by weight, the film thickness of the coating film becomes excessive, so that a good liquid crystal alignment film is difficult to be obtained, and the viscosity of the liquid crystal alignment agent increases, and the coating properties tend to deteriorate. Moreover, the temperature at the time of preparing the liquid crystal aligning agent of this invention becomes like this. Preferably it is 0 degreeC-200 degreeC, More preferably, it is 20 degreeC-60 degreeC.

<Epoxy group-containing compound>

The liquid crystal aligning agent which forms the liquid crystal aligning film of this invention can contain the compound which has at least 1 epoxy group in a molecule as needed. Examples of the epoxy compound having at least one epoxy group in the molecule include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, and 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, etc. are mentioned as a preferable thing. The blending ratio of these epoxy compounds is preferably 40 parts by weight or less, and more preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the polymer.

The liquid crystal aligning agent which forms the liquid crystal aligning film of this invention may contain the functional silane containing compound further from a viewpoint of improving the adhesiveness to the surface of a board | substrate. Examples of such functional silane-containing compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- ( 2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltrier Methoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-tri Methoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecan, 10-triethoxysilyl-1,4,7-triazadecan, 9-trimethoxysilyl- 3,6-diazonyl acetate, 9-triethoxysilyl-3,6-diazanyl acetate, N-benzyl-3-aminopropyl trimethoxysilane, N-ben Jyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-aminopropyltri Methoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, etc. are mentioned. The blending ratio of these functional silane-containing compounds is preferably 40 parts by weight or less, and more preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the polymer.

<Liquid Crystal Display Element>

The liquid crystal display element obtained using the liquid crystal aligning film of this invention can be manufactured, for example by the following method.                     

(1) Applying the liquid crystal aligning agent which forms the liquid crystal aligning film of this invention to one surface of the board | substrate with which the patterned transparent conductive film is formed by methods, such as a roll coater method, a spinner method, and a printing method, and then a coating surface The coating film is formed by heating. Here, as a board | substrate, For example, glass, such as float glass and a soda glass; A transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate or the like can be used. As the transparent conductive film formed on one surface of the substrate, an NESA film (registered trademark of PPG Co., Ltd.) made of tin oxide (SnO ₂ ), an ITO film made of indium tin oxide (In ₂ O ₃ -SnO ₂ ), or the like can be used. have. For the patterning of these transparent conductive films, a photo etching method or a method of using a mask in advance is used. When the liquid crystal aligning agent is applied, a functional silane-containing compound, a functional titanium-containing compound, or the like may be applied to the surface of the substrate in order to further improve the adhesion between the substrate surface and the transparent conductive film and the coating film. The heating temperature after liquid crystal aligning agent application | coating is preferably 80-300 degreeC, More preferably, it is 120-250 degreeC. Moreover, although the liquid crystal aligning agent of this invention containing polyamic acid forms the coating film which becomes an oriented film by removing an organic solvent after application | coating, it can also be made into the imidized coating film by further heating dehydration ring-closed. The film thickness of the coating film formed becomes like this. Preferably it is 0.001-1 micrometer, More preferably, it is 0.005-0.5 micrometer.

(2) A rubbing treatment is performed in which the formed coating film surface is rubbed in a predetermined direction by a roll wound with a cloth made of fibers such as nylon, rayon, or cotton. Thereby, the orientation ability of liquid crystal molecules is provided to a coating film, and it becomes a liquid crystal aligning film.

Further, the liquid crystal alignment film formed by the liquid crystal alignment agent of the present invention is free by partially irradiating ultraviolet rays as shown in, for example, Japanese Patent Application Laid-Open No. 6-222366 or Japanese Patent Application Laid-Open No. 6-281937. The resist film is partially formed on the surface of the liquid crystal alignment film subjected to the rubbing treatment shown in Japanese Patent Application Laid-open No. Hei 5-107544 or subjected to a rubbing treatment in a direction different from the previous rubbing treatment. By removing the resist film and changing the liquid crystal alignment ability of the liquid crystal alignment film, it is possible to improve the clock characteristic of the liquid crystal display element.

(3) The two board | substrates with a liquid crystal aligning film were produced as mentioned above, two board | substrates are opposingly arranged through a gap (cell gap), and the peripheral part of two board | substrates is bonded together using a sealing agent, The liquid crystal is injected and filled into the cell gap partitioned by the substrate surface and the sealing agent, and the injection hole is sealed to form a liquid crystal cell. And the liquid crystal display element of this invention is obtained by bonding a polarizing plate to the outer surface of a liquid crystal cell, ie, the other surface side of each board | substrate which comprises a liquid crystal cell.

As the sealant, for example, an epoxy resin or the like containing an aluminum oxide sphere as a curing agent and a spacer can be used.

Examples of the liquid crystal include nematic liquid crystals, and for example, chief base liquid crystals, subfamily clock liquid crystals, biphenyl liquid crystals, phenylcyclohexane liquid crystals, ester liquid crystals, terphenyl liquid crystals and biphenyls. Cyclohexane type liquid crystal, a pyrimidine type liquid crystal, a dioxane type liquid crystal, a bicyclooctane type liquid crystal, a cuban type liquid crystal, etc. can be used. Moreover, it is sold to these liquid crystals as cholesteric liquid crystals, such as cholestyl chloride, cholesteryl nonate, cholesteryl carbonate, and brand name "C-15", "CB-15" (made by Merck company), for example. The chiral agent etc. which were present can also be added and used.

Moreover, as a polarizing plate bonded to the outer surface of a liquid crystal cell, the polarizing plate which made the cellulose acetate protective film insert the polarizing film called the H film which absorbed iodine, and extended | stretched polyvinyl alcohol, or the polarizing plate which consists of H films themselves.

<Liquid crystal aligning film peeling liquid>

As a peeling liquid used for peeling the liquid crystal aligning film of this invention from a board | substrate, For example, Aqueous peeling liquid or N-methylpyrrolidone or (gamma) which contain a glycol solvent and an alkaline compound and / or nonionic surfactant is used. An organic solvent peeling liquid containing butyrolactone is mentioned.

Examples of the glycol solvent contained in the aqueous solution stripping solution include ethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monoisopropyl ether, diethylene glycol monobutyl ether acetate, and the like.

As the alkaline compound, for example, lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium hydrogen phosphate, diammonium hydrogen phosphate, dipotassium hydrogen phosphate, dihydrogen hydrogen phosphate, ammonium dihydrogen phosphate, potassium dihydrogen phosphate, sodium dihydrogen phosphate Lithium silicate, sodium silicate, potassium silicate, lithium carbonate, sodium carbonate, potassium carbonate, lithium borate, potassium borate, sodium borate, potassium borate, ammonia, tetramethylammonium hydroxide, 2 hydroxyethyltrimethylammonium hydroxide, monomethylamine Dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, ethanolamine, N-methylpiperidine, trimethylhydroxyethylammonium hydroxide, and the like. I can lift it.

As the nonionic surfactant, for example, polyoxyethylene alkyl ether, polyoxyethylene allyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene derivative, oxyethylene-oxypropylene block copolymer, sorbitan fatty acid ester, polyoxy Ethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene alkylamine and the like.

As the organic solvent stripping solution, for example, a stripping solution made of N-methylpyrrolidone or γ-butyrolactone or containing 20% or more thereof and 0 to 20% of the alkaline compound may be mentioned. have.

EXAMPLE

Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not restrict | limited to these Examples.

The peelability of the liquid crystal aligning film in the Example and comparative example of this specification was calculated | required from visually confirming the presence or absence of the film | membrane before and after immersing the coating film on a glass substrate in peeling liquid. The rubbing resistance was obtained by rubbing a coating film formed on a glass substrate 10 times and confirming the presence or absence of wear. In addition, the orientation and the reliability test of the liquid crystal display element produced using this alignment film were evaluated by the following method.

(Orientation Test)                     

The liquid crystal cell was produced from the board | substrate which apply | coated the said orientation film, and it was set as the evaluation of orientation, by checking whether a flow orientation generate | occur | produces when a liquid crystal is vacuum-injected into the cell.

(Reliability test)

The liquid crystal display element was placed in a 70 degreeC thermostat, and it operated continuously for 24 hours by the drive waveform generator "Function / arbitrary waveform generator" (made by Hewlett Packard), and the contrast deviation and the display defect were confirmed.

Synthesis Example 1

2,3,5-tricarboxycyclopentylacetic dianhydride 224.17 g (0.5 mole), 1,3,3a, 4,5,9b-hexahydro-5-methyl-5- (tetra) as tetracarboxylic dianhydride 157.14 g (0.5 mole) of hydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 94.62 g of p-phenylenediamine as a diamine compound ( 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) ) And 4.04 g (0.03 mol) of 4-aminophenyloctadecyl ether were dissolved in 4,500 g of N-methyl-2-pyrrolidone and allowed to react at 60 ° C for 6 hours. Then, the reaction solution was poured into a large excess of methyl alcohol to precipitate the reaction product. Thereafter, the resultant was washed with methyl alcohol and dried at 40 ° C. under reduced pressure for 15 hours to obtain 410 g of polyamic acid having a logarithmic viscosity of 0.87 d 1 / g and an imidation ratio of 0%. 30 g of the obtained polyamic acid was dissolved in 570 g of N-methyl-2-pyrrolidone, and 23.4 g of pyridine and 18.1 g of acetic anhydride were added, and the resultant was dehydrated and closed for 4 hours at 110 ° C. It carried out and obtained 17.5 g of polyimides (this is called "polyimide (A-1)") of 0.80 d1 / g of algebraic viscosity and 100% of imidation ratio.                     

Synthesis Example 2

2,3,5-tricarboxycyclopentylacetic acid dianhydride 224.17 g (0.5 mol), 1,3,3a, 4,5,9b-hexahydro-5-methyl-5 (tetrahydro) as tetracarboxylic dianhydride -2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione, 157.14 g (0.5 mol), 94.62 g of p-phenylenediamine as a diamine compound ( 0.875 mol), 24.85 g (0.1 mol) of bisaminopropyltetramethyldisiloxane, 6.43 g (0.01 mol) of 3,6-bis (4-aminobenzoyloxy) cholestane, 4.04 g (0.03 of 4-aminophenyloctadecyl ether) Mole) 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 the reaction product. Thereafter, the resultant was washed with methyl alcohol and dried at 40 ° C. under reduced pressure for 15 hours to obtain 370 g of a polyamic acid having a logarithmic viscosity of 0.82 d1 / g and an imidation ratio of 0%. 30 g of the obtained polyamic acid was dissolved in 570 g of N-methyl-2-pyrrolidone, and 23.4 g of pyridine and 18.1 g of acetic anhydride were added thereto, followed by dehydration and ring closure at 110 ° C. for 4 hours. It carried out and obtained 18.5g of polyimide (this is called "polyimide (A-2)") of 0.77 dl / g of algebraic viscosity and 100% of imidation ratio.

Synthesis Example 3

218.12 g (1 mol) of pyromellitic dianhydrides as tetracarboxylic dianhydride and 108.14 g (1 mol) of p-phenylenediamine as a diamine compound are dissolved in 4500 g of N-methyl- 2-pyrrolidone, and it is 60 degreeC The reaction was carried out for 6 hours. Then, the reaction solution was poured into a large excess of methyl alcohol to precipitate the reaction product. 410 g of polyamic acid (this is called "polyamic acid (B-1)") having a logarithmic viscosity of 0.90d1 / g and an imidation ratio of 0% by washing with methyl alcohol and drying at 40 ° C under reduced pressure for 15 hours. Got it.

Synthesis Example 4

In Synthesis Example 3, except that tetracarboxylic dianhydride was used as 109.06 g (0.5 mol) of pyromellitic dianhydride and 98.06 g (0.5 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride 485 g of polyamic acid (this is called "polyamic acid (B-2)") was obtained in the same manner as in Synthesis example 1.

Synthesis Example 5

In Synthesis Example 3, a polyamic acid was obtained in the same manner as in Synthesis Example 3 except that diamine was changed to 198.28 g (1 mol) of 4,4'-diaminodiphenylmethane (this is referred to as "polyamic acid (B-3)"). 406 g were obtained.

Synthesis Example 6

A polyamic acid was synthesized in the same manner as in Synthesis Example 3 except that diamine was used as 2,2'-dimethyl-4,4'-diaminobiphenyl 212 g (1.0 mol) in Synthesis Example 3. 475 g was obtained.

Comparative Synthesis Example 1

Synthesis except that 196.12 g (1 mol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 108.14 g (1 mol) of p-phenylenediamine were used as a diamine compound as tetracarboxylic dianhydride. In the same manner as in Example 3, 276 g of a polyamic acid having a logarithmic viscosity of 1.95 d1 / g (this is referred to as "polyamic acid (B-5)") was obtained.

Comparative Synthesis Example 2                     

Tetracarboxylic dianhydride 1,3,3a, 4,5,9b-hexahydro-5-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1, 314.28 g (1 mol) of 2-c] -furan-1,3-dione and 410.52 g (1.0 mol) of 2,2-bis [4- (4-aminophenoxy) phenyl] propane as diamine compounds were used. In the same manner as in Synthesis Example 1, 300 g of a polyamic acid having a logarithmic viscosity of 0.83 d1 / g (referred to as "polyamic acid (B-6)") was obtained and imidized in the same manner as in Synthesis Example 2 using the same. The reaction was carried out to obtain a polyimide having a logarithmic viscosity of 1.28d1 / g (this is referred to as "polyimide (A-3)").

Example 1

The polyimide (A-1) obtained in Synthesis Example 1 and the polyamic acid (B-1) obtained in Synthesis Example 3 were dissolved in N-methyl-2-pyrrolidone / γ-butyrolactone (1/9) mixed solvent. It was made into the solution of 4 weight% of solid content concentration, this solution was filtered using the filter of 1 micrometer of pore diameters, and the liquid crystal aligning agent was prepared. The liquid crystal aligning agent was applied to a transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film using a liquid crystal aligning film coating printer, dried for 10 minutes on a 180 ° C. hot plate, and dried to a film thickness of 500 angstroms. A film was formed. When this film was immersed in the oriented film peeling liquid containing a glycol solvent and a nonionic surfactant for 10 minutes, and peeling was confirmed visually, it peeled. The rubbing process was performed 10 times by the rubbing machine which has the roll which wound the cloth made of rayon to this film at the rotation speed of 400 rpm, the moving speed of 3 cm / sec of a stage, and 0.4 mm of hair pushing lengths, and the rubbing tolerance test was done. As a result, wear and peeling could not be confirmed. On the other hand, after immersing the said orientation film application board | substrate which performed the rubbing process once in water for 1 minute, both board | substrates were dried for 10 minutes in the clean oven of 100 degreeC. Next, an epoxy resin adhesive containing 5.5 μm in diameter of divinylbenzene sphere was applied to each outer edge of the liquid crystal alignment film of the pair of rubbing treated liquid crystal alignment plate, and then the liquid crystal alignment layer faced the pair of liquid crystal support plates. Overlaid and pressed to cure, and the adhesive was cured. Subsequently, after filling a nematic liquid crystal (MLC-6221, Merck Co., Ltd.) between a pair of board | substrates from a liquid crystal inlet, the liquid crystal inlet is sealed with an acryl-type photocuring adhesive, and a polarizing plate is bonded to both surfaces of the outer side of a board | substrate, and a liquid crystal display is carried out. The device was manufactured. No flow orientation was seen, and no contrast deviation and no display defect were seen after the reliability test.

Examples 2-8, Comparative Examples 1-2

Synthesis Examples 2 to 6, Comparative Synthesis Examples 1 and 2, which are liquid crystal alignment films, and Example 1 in Japanese Patent Application Laid-open No. Hei 8-220541, are liquid crystal alignment films formed of a mixed solution of a polyimide precursor solution and a soluble polyimide solution as described above. A liquid crystal display device was produced in the same manner as in Example 1 except that the obtained polyamic acid and / or polyimide was used. In Examples and Comparative Examples, polyamic acid and polyimide were used at a ratio of polyamic acid: polyimide = 4: 1 (weight ratio). The results are shown in Table 1.

Example / Comparative Example Polyimide Polyamic acid Peelability Rubbing resistance Orientation responsibility Example 2 A-2 B-1 Peeling No wear, no peeling No liquid orientation Contrast deviation, no indication loss Example 3 A-1 B-2 Peeling No wear, no peeling No liquid orientation Contrast deviation, no indication loss Example 4 A-2 B-2 Peeling No wear, no peeling No liquid orientation Contrast deviation, no indication loss Example 5 A-1 B-3 Peeling No wear, no peeling No liquid orientation Contrast deviation, no indication loss Example 6 A-2 B-3 Peeling No wear, no peeling No liquid orientation Contrast deviation, no indication loss Example 7 A-1 B-4 Peeling No wear, no peeling No liquid orientation Contrast deviation, no indication loss Example 8 A-2 B-4 Peeling No wear, no peeling No liquid orientation Contrast deviation, no indication loss Comparative Example 1 A-3 B-4 Cannot be peeled off No wear, no peeling No liquid orientation Contrast deviation, no indication loss Comparative Example 2 A-3 B-4 Cannot be peeled off No wear, no peeling No liquid orientation Contrast deviation, no indication loss

ADVANTAGE OF THE INVENTION According to this invention, the liquid crystal display element excellent in high reliability, high liquid crystal orientation, and high rubbing tolerance can be provided, and an alignment film can be peeled easily for board | substrate regeneration.

The liquid crystal display device having the liquid crystal alignment film made of the liquid crystal alignment agent of the present invention can be suitably used for TN type and STN type liquid crystal display elements, and by selecting a liquid crystal to be used, a SH (Super Homeotropic) type and an IPS (In- Plane Switching), ferroelectric and antiferroelectric liquid crystal display devices can be suitably used.

In addition, the liquid crystal display device of the present invention can be effectively used for various devices, and can be used for display devices such as a table calculator, a wristwatch, a table clock, a counting plate, a word processor, a personal computer, a liquid crystal television, and the like. .

Claims (5)

A liquid crystal aligning agent comprising a mixture of polyimide and polyamic acid formed by reaction of tetracarboxylic dianhydride and diamine, wherein the tetracarboxylic dianhydride with respect to the mixture is 1,2,3,4-cyclobutane Tetracarboxylic dianhydride, 3,3 ', 4,4'-dicyclohexyl tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic dianhydride, 3,5,6-tricarboxyno Bonane-2-acetic acid dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, bicyclo [2.2.2] -octo-7-ene-2,3,5,6-tetra Carboxylic dianhydride, 1,3,3a, 4,5,9b-hexahydro-8-methyl-5- (tetrahydro-2,5-dioxo-3-furanyl) naphtho [1,2- c] at least 3 selected from the group consisting of furan-1,3-dione and pyromellitic dianhydride, and the diamine is p-phenylenediamine, bisaminopropyltetramethyldisiloxane, 4,4 ' Diaminodiphenylmethane, 2, A liquid crystal aligning agent comprising at least three selected from the group consisting of 2'-dimethyl-4,4'-diaminobiphenyl and 3,6-bis (4-aminobenzoyloxy) cholestane. The liquid crystal aligning agent according to claim 1, wherein the tetracarboxylic dianhydride contains 30 mol% or more of pyromellitic dianhydride. The liquid crystal aligning agent according to claim 1 or 2, further comprising a compound having at least one epoxy group in the molecule. The liquid crystal aligning film formed from the liquid crystal aligning agent of Claim 1 or 2. The liquid crystal aligning film of Claim 4 is provided, The liquid crystal display element characterized by the above-mentioned.