KR100719425B1 - Liquid Crystal Aligning Film and Liquid Crystal Display Device - Google Patents

Abstract

The present invention provides a liquid crystal alignment film containing a polyamic acid and a polyimide, and capable of expressing good orientation characteristics, and having a high voltage retention and no contrast unevenness or display defect when a voltage is applied for a long time. will be.

The present invention also provides a liquid crystal alignment film comprising (a) a polymer having an imide bond unit or a polymer having both an amic acid bond unit and an imide bond unit, wherein the imide bond unit and the amic acid bond in the polymer A percentage ratio of the number of imide bond units to the total number of bond units of units is 30 to 100%, and (b) a liquid crystal alignment film having a polar value of surface tension of 10 dyn / cm or more.

Polyamic acid, polyimide, a liquid crystal aligning film, voltage retention, display defect, contrast unevenness, the polarity value of surface tension, a liquid crystal display element.

Description

Liquid Crystal Alignment Film and Liquid Crystal Display Device

The present invention relates to a liquid crystal alignment film and a liquid crystal display element. More specifically, in a liquid crystal display device which is excellent in voltage retention and liquid crystal alignment property, and particularly exhibits a threshold voltage of 3 V or less, a liquid crystal alignment film capable of preventing display defects such as contrast unevenness and display defects occurring after long-term voltage application; It relates to the liquid crystal display device.

Conventionally, a nematic liquid crystal layer having positive dielectric anisotropy is formed between two substrates on which a liquid crystal alignment layer is formed on the surface through a transparent conductive film, thereby making a cell having a sandwich structure, and the long axis of the liquid crystal molecules differs from one substrate to another. A TN type liquid crystal display element having a TN (Twisted Nematic) type liquid crystal cell which is continuously twisted 90 degrees to the substrate of the side is known.

In addition, the addition of a chiral agent causes the long axis of the liquid crystal molecules to be continuously twisted over 180 degrees between the substrates, and there is also a STN (Super Twisted Nematic) type liquid crystal display device using the birefringence effect. do. Also, recently, a nematic liquid crystal layer or spiral axis in a homeotropic alignment state having negative dielectric anisotropy between opposing substrates forms a cholesteric liquid crystal layer in parallel with the normal of the substrate to form a pigment in these liquid crystal layers. The guest-host reflection type liquid crystal display element which added is also developed. Orientation of the liquid crystal in these liquid crystal display elements is normally expressed by the liquid crystal aligning film in which the rubbing process was performed. As a material of the liquid crystal aligning film which comprises a liquid crystal display element here, 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 been remarkably developed as high-performance display devices in terms of size, weight reduction, low power consumption, and the like. In particular, in the low voltage drive type liquid crystal display element for the purpose of low power consumption, the demand for the reliability test which applies voltage for a long time at high voltage retention or high temperature is increasing. However, in the liquid crystal aligning film containing the polyamic acid which is a precursor of the polyimide known conventionally, the imide type polymer which has a structure obtained by dehydrating and ring-closing it, etc., when a liquid crystal display element is manufactured using this liquid crystal aligning film, the liquid crystal aligning ability, for example, Even if it was excellent and the pretilt angle was stable, there existed many problems that sufficient voltage retention was not obtained or contrast spots and display defects generate | occur | produce during the reliability test of a liquid crystal display element. For this reason, since the precursor and polyimide of the polyimide which have alicyclic structure show a higher voltage retention and show a favorable result also in a reliability test, when making the precursor and polyimide of polyimide which have alicyclic structure as a liquid crystal aligning film, There are many. However, the liquid crystal aligning film produced only by such knowledge had a problem which does not show durability to sufficient reliability test.

An object of the present invention includes polyamic acid and polyimide, which are precursors of polyimide useful as a liquid crystal aligning film, can exhibit good orientation characteristics, high voltage retention, and lack of contrast unevenness and display when a long time voltage is applied. It is providing the liquid crystal aligning film which did not generate | occur | produce.

Another object of the present invention is to provide a liquid crystal display device having the liquid crystal alignment film of the present invention which exhibits the excellent performance as described above.

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

Firstly, the above objects and advantages of the present invention are

(a) A liquid crystal aligning film containing a polymer having an imide bond unit or a polymer having both an amic acid bond unit and an imide bond unit, wherein the total bond units of the imide bond unit and the amic acid bond unit in the polymer The percentage ratio of the number of imide bond units to the number is 30 to 100%,

(b) the polarity value of the surface tension is 10 dyn / cm or more

It is achieved by the liquid crystal aligning film characterized by the above-mentioned.

Secondly, according to the present invention, the above objects and advantages of the present invention are achieved by a liquid crystal display device fabricated with the liquid crystal alignment film of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail. The liquid crystal aligning film in this invention is normally formed by apply | coating the liquid crystal aligning agent containing a polyimide and / or the polyamic acid which is its precursor on a transparent electrode substrate, and then drying (usually heat-drying), and rubbing etc. It is used after performing an orientation treatment on the film surface. Polyimide and polyamic acid can be used individually or in combination of 2 types or more, respectively. In addition, when the liquid crystal aligning agent used in the present invention contains both polyimide and polyamic acid, a mixture of polyimide and polyamic acid may be contained, and a polymer having an imide bond unit and an amide bond unit may be contained.

Also in the polymer, the imide bond unit and the amide bond unit may be contained randomly or in blocks.

In the liquid crystal aligning film of this invention, in the process of apply | coating and drying the said liquid crystal aligning agent on a board | substrate, you may heat-dry, and the amide bond unit in this liquid crystal aligning agent may be dehydrated-closed and the imide bond unit may be formed. The percentage ratio of the number of imide bond units with respect to the total number of bond units of the imide bond unit and the amic acid bond unit in the polymer forming the liquid crystal alignment film of the present invention to be obtained is hereinafter referred to as "imidization rate". 100%, especially when used in a TN-TFT type device, it is preferably 30 to 70% because of no sticking and high reliability.

<Polyamic acid>

The polyamic acid used in the present invention can be obtained by ring-opening polyaddition of tetracarboxylic dianhydride and diamine compound.

Tetracarboxylic dianhydride

As tetracarboxylic dianhydride used for the synthesis reaction of such polyamic acid which is a precursor of a polyimide, for example, butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic 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'-dicyclohexyl tetracarboxylic dianhydride , 2,3,5-tricarboxycyclopentylacetic dianhydride, 3,5,6-tricarboxynorbornane-2-acetic acid dianhydride, 2,3,4,5-tetrahydrofurantetetracarboxylic 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-l, 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) -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-dione, 5- (2,5-dioxotetrahydrofuranyl)- 3-Methyl-3-cyclohexene-1,2-dicarboxylic dianhydride, bicyclo [2,2,2] -octo-7-ene-2,3,5,6-tetracarboxylic dianhydride Aliphatic and alicyclic tetracarboxylic dianhydrides such as compounds represented by the following formulas (1) and (2);

Pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-biphenylsulfontetracarboxylic 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'-tetraphenylsilanetetracarboxylic dianhydride, 1,2,3,4-furantetracarboxylic Acid dianhydrides, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylsulfide dianhydrides, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydrides, 4 , 4'-bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride, 3,3 ', 4,4'-perfluoroisopropylidenediphthalic 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 (anhydrotrimelitate), propylene glycol -bis (anhydrotrimelitate), 1,4-butanediol-bis (anhydrotrimelitate), 1,6-hexanediol-bis (an Hydrotrimellitate), 1,8-octanediol-bis (anhydrotrimelitate), 2,2-bis (4-hydroxyphenyl) propane-bis (anhydrotrimelitate), the following formulas 3 to Aromatic tetracarboxylic dianhydrides, such as the compound represented by 6, are mentioned. These are used individually by 1 type or in combination of 2 or more types.

In the formula,

R ¹ and R ⁴ represent a divalent organic group having 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.

Of these, butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic 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-tri Carboxynorbornane-2-acetic acid dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, bicyclo [2.2.2] -octo-7-ene-2,3,5,6 Tetracarboxylic dianhydride, cis-3,7-dibutylcycloocta-1,5-diene-1,2,5,6-tetracarboxylic dianhydride The aliphatic compound containing an acid anhydride such as water is preferred.

As a diamine compound used for the synthesis reaction of polyamic acid, it is p-phenylenediamine, m-phenylenediamine, 4,4'- diamino diphenylmethane, 4,4'- diamino diphenylethane, 4, for example. , 4'-diaminodiphenylsulfide, 4,4'-diaminodiphenylsulfone, 3,3'-dimethyl-4,4'-diamino biphenyl, 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-aminophenyl) -10-hydroanthracene, 2,7-diaminofluorene, 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-trifluoromethylphenoxy) Phenyl] hexafluoropropane, 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl, 4,4'-bis [(4-amino-2-trifluoromethyl) phenoxy Aromatic diamines such as ci] -octafluorobiphenyl;

1,1-methaxylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 4,4-diaminoheptamethylenediamine, 1 , 4-diaminocyclohexane, isophoronediamine, tetrahydrodicyclopentadienylenediamine, hexahydro-4,7-methanoindenylenedimethylenediamine, tricyclo [6,2,1, O ^2.7 ] -unde Aliphatic and alicyclic diamines such as silendimethyldiamine and 4,4'-methylenebis (cyclohexylamine);

Monocyclic phenylenediamines represented by the following formula (7); The diamino organosiloxane represented by following formula (8), the compound represented by following formula (9) -13, etc. are mentioned. These diamine compounds can be used individually or in combination of 2 or more types.

In the formula,

R ⁵ represents a divalent organic group selected from -O-, -COO-, -OCO-, -NHCO-, -CONH- and -CO-,

R ⁶ represents a monovalent organic group having a steroid structure or a trifluoromethyl group.

In the formula,                     

R ⁷ represents a hydrocarbon group having 1 to 12 carbon atoms, and a plurality of R ^{7 's} may be the same or different, and

p is an integer of 1 to 3,

q is an integer of 1-20.

In the formula,

y is an integer from 2 to 12,

z is an integer from 1 to 5.

The use ratio of the tetracarboxylic dianhydride and the diamine compound used in the polyamic acid synthesis reaction is 0.2 to 2 equivalents of the acid anhydride group contained in the tetracarboxylic dianhydride relative to 1 equivalent of the amino group included in the diamine compound. The ratio which becomes this is preferable, and the ratio which becomes 0.3-1.4 equivalent is more preferable. When 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 falls There is.

In this invention, the polyamic acid which comprises a liquid crystal aligning agent is synthesize | combined by reaction of tetracarboxylic dianhydride and a diamine compound. Synthesis reaction of polyamic acid is performed in organic solvent, Preferably it is 0-150 degreeC, More preferably, it is carried out under the temperature conditions of 0-100 degreeC. When reaction temperature is 0 degrees C or less, the solubility to the 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 thereof. For example, γ-butyrolactone and N- Methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetoamide, dimethyl sulfoxide, tetramethylurea, hexamethylphosphoryltriamide, 1,3-dimethyl-2-imidazoli Aprotic polar solvents such as dinon; Phenol solvents, such as m-cresol, xylenol, a phenol, and a halogenated phenol, are mentioned.

The amount of the organic solvent (A) is preferably an amount such that the total amount (B) of the 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.

In the organic solvent, alcohols, ketones, esters, ethers, halogenated hydrocarbons, hydrocarbons, and the like, which are poorly soluble solvents of polyamic acid, may be used in combination within the range in which the produced polyamic acid is not precipitated. Specific examples of such poorly soluble solvents include methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclo Hexanone, 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, pro Ethylene 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 , Ethyl 2-hydroxypropionate, ethyl lactate, methyl lactate, butyl lactate, ethyl ethoxyacetate, ethyl hydroxyacetate, 2-hydroxy-3-methylbutane, methyl 3-methoxypropionate, 3-methoxy Ethyl propionate, 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-dichlorobenzene, hexane, heptane And octane, benzene, toluene, xylene and the like. These can be used individually by 1 type or in combination of 2 or more types.

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

<Polyimide>                     

The polyimide which comprises the liquid crystal aligning agent of this invention can be manufactured by the following method (1)-(3). In addition, a polymer having a so-called imidation ratio of less than 100% in which a part of the repeating unit of the polyamic acid is dehydrated and closed is also suitably used in the liquid crystal aligning agent of the present invention.

Method (1): A method of heating and dehydrating the polyamic acid to ring closure.

In this method, the reaction temperature is preferably 60 to 300 ° C, more preferably 120 to 250 ° C. If reaction temperature is less than 60 degreeC, imidation reaction will not fully advance but if reaction temperature exceeds 250 degreeC, the molecular weight of the polyimide obtained may become small.

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

In this method, anhydrides such as acetic anhydride, propionic anhydride and trifluoroacetic anhydride can be used as the dehydrating agent. The amount of the dehydrating agent is preferably 1.6 to 20 moles with respect to 1 mole of the repeating unit of the polyamic acid. As the imidation catalyst, tertiary amines such as pyridine, collidine, lutidine and triethylamine can be used, for example. However, it is not limited to these. As for the usage-amount of the imidation catalyst, 0.5-10 mol is preferable with respect to 1 mol of dehydrating agents used. As an organic solvent used for imidation reaction, the same organic solvent as what was illustrated by the organic solvent 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 60-1500 degreeC.

Method (3): The method of condensing by mixing tetracarboxylic dianhydride and a diisocyanate compound.

Specific examples of the diisocyanate compound used in this method include aliphatic diisocyanate compounds such as hexamethylene diisocyanate; Alicyclic diisocyanate compounds 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, diphenyldichloromethane-4,4'-diisocyanate, diphenylfluoromethane-4, Aromatic diisocyanate compounds, such as 4'- diisocyanate, benzophenone-4,4'- diisocyanate, and N-phenylbenzoic acid amide-4,4'- diisocyanate, are mentioned. These can be used individually or in combination of 2 or more types. The catalyst is not particularly required for this method, and the reaction temperature is preferably 50 to 200 ° C, more preferably 100 to 160 ° C.

Thus, a polyimide can be refine | purified by performing the operation similar to the purification method of a polyamic acid with respect to the polymer solution obtained in this way.

<Intrinsic Viscosity of Polyamic Acid and Polyimide>

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

<Terminal modified polymer>                     

The polyamic acid and polyimide used for the liquid crystal aligning agent which forms the liquid crystal aligning film of this invention may be a terminal modified polymer. This terminal-modified polymer can improve the application | coating characteristic of a liquid crystal aligning agent, etc. without adjusting molecular weight and impairing the effect of this 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 modified polymer, maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecyl succinic anhydride, n-tetradecylsuccinic anhydride, n-hexadecylsuccinic 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>

The liquid crystal aligning film of this invention is formed with the liquid crystal aligning agent comprised by melt | dissolving and containing the said polyimide and / or polyamic acid normally in an organic solvent.

As an organic solvent which comprises the liquid crystal aligning agent of this invention, the thing similar to the organic solvent illustrated as an organic solvent used for the synthesis reaction of polyamic acid is mentioned. In addition, the same poorly soluble solvents as those exemplified as the poorly soluble solvents that can be used in the synthesis reaction of the polyamic acid can be appropriately selected and used in combination.

Solid content concentration in the liquid crystal aligning agent which provides the liquid crystal aligning film of this invention is chosen in consideration of viscosity, volatility, etc., Preferably it is the range of 1 to 10 weight%. That is, although the liquid crystal aligning agent of this invention forms a coating film which becomes a liquid crystal aligning film by apply | coating to the surface of a board | substrate, when solid content concentration is less than 1 weight%, the film thickness of this coating film becomes too thin and it is difficult to obtain a favorable liquid crystal aligning film. When solid content concentration exceeds 10 weight%, the film thickness of a coating film becomes too thick and it is difficult to obtain a favorable liquid crystal aligning film, and the viscosity of a liquid crystal aligning agent increases, and coating property tends to fall. Moreover, the temperature at the time of manufacturing 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.

It is preferable that the liquid crystal aligning agent which forms the liquid crystal aligning film of this invention contains the compound which has one or more epoxy groups in a molecule | numerator from a viewpoint of improving the adhesiveness to a board | substrate surface. Examples of such epoxy group-containing compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropyl 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. These epoxy compounds can be used individually or in combination of 2 or more types. The blending ratio of these epoxy compounds is preferably 40 parts by weight or less, more preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the polymer.

Moreover, the liquid crystal aligning agent which forms the liquid crystal aligning film of this invention can contain a functional silane containing compound from a viewpoint of improving the adhesiveness to the surface of a board | substrate. As such a functional silane containing compound, 3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, 2-aminopropyl trimethoxysilane, 2-aminopropyl triethoxysilane, 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-trimethoxy Silylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3, 6-diazonyl acetate, 9-triethoxysilyl-3,6-diazanyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-ben Jyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene) -3-aminopropyl tri Methoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, etc. The compounding ratio of these functional silane containing compounds becomes like this. Preferably it is 40 weight part or less with respect to 100 weight part of polymers, More preferably, it is 0.1-30 weight part.

<Liquid crystal aligning film and liquid crystal display element>

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

(1) The liquid crystal aligning agent which forms the liquid crystal aligning film of this invention on one surface of the board | substrate with which the patterned transparent conductive film is provided is apply | coated by methods, such as a roll coating method, the spinning method, the printing method, and then a coating surface. The coating film is formed by heating. 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. Transparent conductive films provided on one side of the substrate include NESA films (registered trademark of PPG, USA) made of tin oxide (SnO ₂ ), and ITO films made of indium tin oxide (In ₂ O ₃ -SnO ₂ ). Etc. can be used. The photoetching method or the method using a preliminary mask is used for patterning these transparent conductive films. In application | coating of a liquid crystal aligning agent, in order to make the adhesiveness of a board | substrate surface, a transparent conductive film, and a coating film favorable, you may apply | coat a functional silane containing compound, a functional titanium containing compound, etc. previously on the said surface of a board | substrate. The heating temperature after liquid crystal aligning agent application becomes like this. Preferably it is 80-300 degreeC, More preferably, it is 120-250 degreeC. In addition, although the liquid crystal aligning agent of this invention containing a polyamic acid forms the coating film which becomes an orientation film by removing an organic solvent after application | coating, you may form a coating film using the imidized thing by advancing dehydration ring-close by heating. The film thickness of the coating film formed becomes like this. Preferably it is 0.1-1 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 constant direction with a roll of cloth made of fibers such as nylon, rayon, cotton, or the like. Thereby, the orientation ability of liquid crystal molecules is provided to a coating film, and a liquid crystal aligning film is manufactured.

Moreover, the ultraviolet-ray as described in Unexamined-Japanese-Patent No. 6-222366 and Unexamined-Japanese-Patent No. 6-281937 to the liquid crystal aligning film formed by the liquid crystal aligning agent of this invention partially, for example. The resist film is partially formed on the surface of the liquid crystal alignment film subjected to the treatment of changing the pretilt angle by irradiation or the rubbing treatment as described in JP-A-5-107544, and rubbing in a direction different from the rubbing treatment described above. After the treatment, the resist film is removed to perform the treatment of changing the liquid crystal alignment ability of the liquid crystal alignment film, thereby improving the field of view characteristics of the liquid crystal display element.

 Moreover, the liquid crystal display element of this invention is obtained by performing the following processes following the said process, for example.

 (3) The two substrates in which the liquid crystal alignment film was formed as described above were prepared, and the two substrates were disposed to face each other with a gap (cell gap), and the peripheral portions of the two substrates were bonded together using a sealing agent, and the substrate surface and the sealing agent were used. The liquid crystal is injected and filled into the partitioned cell gap and the injection hole is sealed to form a liquid crystal cell. And a liquid crystal display element can be 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 sealing agent, for example, an epoxy resin containing aluminum oxide spheres as a curing agent and a spacer can be used.

Examples of the liquid crystals include nematic liquid crystals, and for example, cifbase liquid crystals, subfamily clock liquid crystals, biphenyl liquid crystals, phenylcyclohexane liquid crystals, ester liquid crystals, terphenyl liquid crystals, biphenyl cyclohexane liquid crystals, 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 sells to these liquid crystals by cholesteric-type liquid crystals, such as cholestyl chloride, cholesteryl nonate, cholesteryl carbonate, or brand name "C-15" "CB-15" (product made by Merck Corporation), for example. The same chiral agent as that used, etc. can be added and used.

Moreover, as a polarizing plate bonded to the outer surface of a liquid crystal cell, the polarizing plate which carried out the polyvinyl alcohol extending orientation, and absorbed the iodine, the polarizing film called H film | membrane as the cellulose acetate protective film, or the polarizing plate which consists of H film itself is mentioned.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

In the Example and the comparative example of this specification, the imidation ratio of the liquid crystal aligning film was calculated | required by analyzing the coating film on a silicon wafer using FT-IR. In addition, the polarity value of surface tension was computed by the contact angle of water and diiomethane, ie, methylene iodide, with respect to the liquid crystal aligning film formed on the glass substrate. In addition, the voltage retention and the reliability test of the liquid crystal display element produced using this alignment film were evaluated by the following method.

(Imidization rate)

In the FT-IR measurement, the peak area ratio between absorption near 1381 cm ⁻¹ (CNC variable vibration = absorption of imide bond) and absorption near 1503 cm ⁻¹ (absorption of amic acid bond) is already obtained by the following equation (1). The dehydration rate was calculated.

Imidation ratio = {α1 / (αl + α2)} × 100 (%)

α1: peak area of absorption near 1381 cm ⁻¹

α2: peak area of absorption around 1503 cm ^−l

Α2 is 1503 in that the coating film is heated with a 300 ° C. hot plate for 10 minutes.

cm ^-l is the value determined by the peak area in the vicinity of the absorption to zero.

(Surface tension)

See JOURNAL OF APPLIED POLYMER SCIENCE VOL. 13, PP. 1741-1747 (1969) ", the surface free energy (surface tension) of the liquid crystal aligning film was calculated | required from the contact angle of pure water and the contact angle of methylene iodide on a liquid crystal aligning film as follows. 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 represented by the following equation.                     

γ _L : surface free energy of liquid

γ _L ^d : dispersion of surface free energy of liquid

γ _L ^P : Polarity value of surface free energy of liquid

γ ^S _d : dispersion of surface free energy of solid

γ _S ^p : Polarity value of surface free energy of solid

θ: contact angle

Under conditions of 20 ° C., gamma _L = 72.8, gamma _L ^d = 21.8 and gamma _L ^P = 51.0 (all units are dyn / cm) for pure water, gamma _L = 50.8, gamma _L ^d = 49.5 for methylene iodide And γ _L ^P = 1.3. Substituting these values into Equation 2 yields Equation 3 below for pure water and Equation 4 below for methylene iodide. Where θ ₁ and θ ₂ are the contact angles of pure water and methylene iodide, respectively.

Therefore, the measured values of the contact angle were substituted into the above equations (3) and (4), γ _S ^d and γ _S ^p were obtained from the simultaneous equation, and the surface free energy γ _s of the film was obtained by the following equation (5).

The contact angle was calculated | required by using the contact angle measuring apparatus "CA-A type" (made by Kyowa Kaimen Kagaku Co., Ltd.), 4 microliters of water or methylene iodide was dripped on a film, and measuring the contact angle after 1 minute passed.

(Voltage retention)

The liquid crystal display element was left to stand for 10 minutes in a 60 degreeC high temperature bath, and the voltage retention (frame period 16.7 ms) of the liquid crystal display element after standing was measured using "VHR-1" (Toyo Technica).

(Reliability test)

The liquid crystal display element was put in a 70 degreeC thermostat, and it drive for 24 hours continuously by the drive waveform generator "Function / arbitrary waveform generator" (made by Hewlett Packard), and it confirms the presence or absence of a contrast unevenness and display defect.

Synthesis Example 1

224.17 g (1 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride as tetracarboxylic dianhydride and 108.14 g (1 mol) of p-phenylenediamine as diamine compound were added to N-methyl-2-pyrroli. It melt | dissolved in 4500 g of toluco, and made it react at 60 degreeC for 6 hours. The reaction solution was then poured into very excess 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 a polyamic acid having a logarithmic viscosity of 0.90 dl / g and an imidization ratio of 0% (this is referred to as “polyamic acid (A-1)”).

Synthesis Example 2

30 g of the polyamic acid obtained in Synthesis Example 1 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 washed, and depressurized and obtained 17.5g of polyimides (it calls this "polyimide (B-1)") of 0.85 dl / g of logarithmic viscosity and 100% of imidation ratio.

Synthesis Example 3

In Synthesis Example 1, the polyamic acid was referred to in the same manner as in Synthesis Example 1 except that diamine was replaced with 198.27 g (1 mol) of 4,4'-diaminodiphenylmethane (this is referred to as "polyamic acid (A-2)"). ), And an imidization reaction was carried out in the same manner as in Synthesis example 2 to obtain 22.2 g of a polyimide having a logarithmic viscosity of l.16 dl / g (this is referred to as "polyimide (B-2)").

Synthesis Example 4

Polyamic acid (this is called "polyamic acid (A-3)") in the same manner as in Synthesis example 1 except that tetracarboxylic dianhydride was 196.12 g (1 mol) of cyclobutanetetracarboxylic dianhydride in Synthesis Example 1. 420 g was obtained.

Synthesis Example 5

Polyamic acid was synthesized in the same manner as in Synthesis Example 1 except that tetracarboxylic dianhydride was replaced with 109.06 g (0.5 mol) of pyromellitic anhydride and 98.06 g (0.5 mol) of cyclobutanetetracarboxylic dianhydride in Synthesis Example 1. 485 g (this is called "polyamic acid (A-4)") was obtained.

Synthesis Example 6

In Synthesis Example 1, a polyamic acid was prepared in the same manner as in Synthesis Example 1 except that diamine was replaced with 54.7 g (0.5 mol) of p-phenylenediamine and 99.14 g (0.5 mol) of 4,4'-diaminodiphenylmethane. This was called "polyamic acid (A-5)", and the imidation reaction was carried out in the same manner as in Synthesis example 2 using the polyimide having a logarithmic viscosity of 1.08 dl / g (this was referred to as "polyimide (B-3)"). 21 g was obtained.

Synthesis Example 7

In Synthesis Example 1, tetracarboxylic dianhydride was replaced with 109.06 g (0.5 mol) of pyromellitic anhydride and 98.06 g (0.5 mol) of cyclobutanetetracarboxylic dianhydride, and diamine was substituted with p-phenylenediamine 54.7 Polyamic acid (this is called "polyamic acid (A-6)") in the same manner as in Synthesis example 1 except that g (0.5 mol) and 99.14 g (0.5 mol) of 4,4'-diaminodiphenylmethane were replaced with Got it.

Synthesis Example 8

In Synthesis Example 1, tetracarboxylic dianhydride was replaced with 224.00 g (1.0 mol) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride, and diamine was 4,4'-diaminodiphenyl. Polyamic acid was prepared in the same manner as in Synthesis Example 1 except that 99.14 g (0.5 mol) of methane and 205.26 g (0.5 mol) of 2,2-bis [4- (4-aminophenoxy) phenyl] propane were substituted. (A-7) ") 385 g were obtained.

Synthesis Example 9

In the synthesis example 1, tetracarboxylic dianhydride is made into 224.00 g (1.0 mol) of 1,2,4,5-cyclohexane tetracarboxylic dianhydride, and diamine is 4,4'- diamino diphenyl methane. 158.62 g (0.8 mole) and 2,2-bis [4- (4-aminophenoxy) phenyl] propane, except for being replaced with 82.10 g (0.2 mole) of polyamic acid ( A-8) "406 g were obtained.

Synthesis Example 10

224.17 g (0.5 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride as tetracarboxylic dianhydride, 1,3,3a, 4,5,9b-hexahydro-5-methyl-5 (tetrahydro 157.14 g (0.5 mole) of -2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione and 94.62 g (0.875 p-phenylenediamine as diamine compound) Moles), 2,2-ditrifluoromethyl-4,4-diaminobiphenyl 32.02 g (0.1 moles), 3,6-bis (4-aminobenzoyloxy) cholestane 6.43 g (0.01 moles), 4 4.04 g (0.015 mol) of aminophenyloctadecyl ether was dissolved in 4500 g of N-methyl-2-pyrrolidone and allowed to react at 60 ° C for 6 hours. The reaction solution was then poured into very excess methyl alcohol to precipitate the reaction product. Thereafter, the resultant was washed with methyl alcohol and dried under reduced pressure at 40 ° C. for 15 hours to obtain 410 g of polyamic acid having a logarithmic viscosity of 0.87 dl / g and an imidization 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 to dehydrate and close the ring at 110 DEG C for 4 hours. 17.5 g of polyimide (this is called "polyimide (B-4)") of 0.80 dl / g of logarithmic viscosity and 100% of imidation ratio was obtained.

Synthesis Example 11

224.17 g (0.5 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride as tetracarboxylic dianhydride, 1,3,3a, 4,5,9b-hexahydro-5-methyl-5 (tetrahydro 157.14 g (0.5 mole) of -2,5-dioxo-3-furanyl) -naphtho [1,2-c] -furan-1,3-dione and 94.62 g (0.875 p-phenylenediamine as diamine compound) Moles), 24.85 g (0.1 moles) of bisaminopropyltetramethyldisiloxane, 6.43 g (0.01 moles) of 3,6-bis (4-aminobenzoyloxy) cholestane, 4.04 g (0.015 moles of 4-aminophenyloctadecylether) ) Was dissolved in 4500 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 6 hours. The reaction solution was then poured into very excess methyl alcohol to precipitate the reaction product. Thereafter, the resultant was washed with methyl alcohol and dried under reduced pressure at 40 ° C. 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, 23.4 g of pyridine and 18.1 g of acetic anhydride were added and dehydrated and closed for 4 hours at 110 ° C., followed by precipitation, washing and decompression. 18.5 g of polyimide (this is called "polyimide (B-5)") of 0.77 dl / g of logarithmic viscosity and 100% of imidation ratio was obtained.

Synthesis Example 12

Tetracarboxylic dianhydride was replaced with 196.12 g (1.0 mol) of cyclobutanetetracarboxylic dianhydride and 200.2 g (1.0 mol) of diamine in 4,4-diaminodiphenyl ether in the synthesis example 1 Other than 485 g of polyamic acid (this is called "a polyamic acid (A-9)") similarly to the synthesis example 1 was obtained.

Synthesis Example 13

Tetracarboxylic dianhydride in Synthesis Example 1 196.12 g (1.0 mol) of cyclobutanetetracarboxylic dianhydride and diamine in 212 g (1.0 mol) of 2,2-dimethyl-4,4-diaminobiphenyl 475 g of polyamic acid (this was referred to as "polyamic acid (A-10)") was obtained in the same manner as in Synthesis example 1 except for the replacement.

Synthesis Example 14

In Synthesis Example 5, 112.09 g (0.5 mol) of 2,3,5-tricarboxycyclopentylacetic dianhydride as tetracarboxylic dianhydride and 109.06 g (0.5 mol) of pyromellitic anhydride, 2, as a diamine compound A polyamic acid having a logarithmic viscosity of 0.83 dl / g except for using 410.52 g (1.0 mole) of 2-bis [4- (4-aminophenoxy) phenyl] propane (this is referred to as "polyamic acid (A- 11) &quot;) to obtain an imidization reaction in the same manner as in Synthesis example 2 to obtain a polyimide having a logarithmic viscosity of 1.28 dl / g (this is referred to as “polyimide (B-6)”). .

Synthesis Example 15

The logarithmic viscosity was 1.95 dl / g in the same manner as in Synthesis Example 1, except that 218.12 g (1 mol) of pyromellitic anhydride as tetracarboxylic dianhydride and 108.14 g (1 mol) of p-phenylenediamine were used as the diamine compound. 276 g of polyamic acid (this is referred to as "polyamic acid (A-12)") was obtained.

Synthesis Example 16

In Synthesis Example 5, except that the diamine was replaced with 200.2 g (1.0 mol) of 4,4-diaminodiphenyl ether, the polyamic acid having a logarithmic viscosity of 0.9 dl / g was obtained in the same manner as in Synthesis Example 5. -13) "to 380 g.

Synthesis Example 17

1,3,3a, 4,5,9b-hexahydro-5 (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c]-as tetracarboxylic dianhydride 300.3 g (1 mol) of furan-1,3-dione, 97.2 g (0.9 mol) of p-phenylenediamine and 34.8 g (0.1 mol) of 1-hexadecaneoxy-2,4-diaminobenzene as diamine Otherwise, polyamic acid was obtained in the same manner as in Synthesis example 1, and in the same manner as in synthesis example 2, polyimide having an imidation ratio of 100% and a logarithmic viscosity of 0.43 dl / g (this is referred to as "polyimide (B-7)") 295 g Got.

<Example 1>

The polyamic acid (A-1) obtained in Synthesis Example 1 was dissolved in a mixed solvent of N-methyl-2-pyrrolidone / γ-butyrolactone (1/9) to prepare a solution having a solid content of 4% by weight, and this solution Was filtered using a filter having a pore size of 1 m to prepare a liquid crystal aligning agent. The liquid crystal aligning agent was applied onto a silicon wafer, dried for 10 minutes with a 180 ° C. hot plate, and subjected to FT-IR analysis. As a result, the imidation ratio was about 95%. In addition, the polarity value of surface tension calculated from the contact angle of water and diiodomethane with respect to the liquid crystal aligning film formed on the glass substrate was 12 dyn / cm. In addition, 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 by using a printing machine for coating a liquid crystal alignment film, dried on a hot plate at 180 ° C. for 10 minutes, and a film having a dry average film thickness of 500 angstroms. Formed. The rubbing process was carried out by the rubbing machine which has the roll which wound the cloth made from rayon on this film at roll rotation speed 400rpm, the moving speed of 3 cm / sec of a stage, and the press-in length of a thread of 0.4 mm. After immersing the said oriented film coating board | substrate in isopropyl alcohol for 1 minute, both board | substrates were dried for 5 minutes on a 100 degreeC hotplate. Subsequently, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 μm was applied to each edge having a liquid crystal alignment film of the pair of rubbing treated liquid crystal sandwiched substrates, and then the pair of liquid crystal sandwiched substrates were placed on the liquid crystal alignment film surface. The adhesives were cured by overlapping each other so as to face each other. Subsequently, the nematic liquid crystal (MLC-6221, manufactured by Merck Co., Ltd.) was charged between the pair of substrates through the liquid crystal injection hole, and then the liquid crystal injection hole was sealed with an acrylic photocuring adhesive, and the polarizing plates were bonded to both sides of the outside of the substrate to form A display element was produced. The voltage retention showed a high value of 99%, and contrast stains and display defects were not confirmed after the reliability test.                     

<Examples 2 to 20 and Comparative Examples 1 to 5>

Liquid crystals were prepared in the same manner as in Example 1 except that the polarization values of the imidation ratio and the surface tension of the liquid crystal alignment film were changed by using the polyamic acid and / or polyimide obtained in Synthesis Examples 2 to 7 and changing the drying temperature of the liquid crystal alignment film. A display element was produced. In Examples 13, 14, 17, 18, l9, 20 and Comparative Examples 4 and 5, polyamic acid and polyimide were used at a ratio of polyamic acid: polyimide = 4: 1 (weight ratio). The results are shown in Table 1.

When producing a liquid crystal display element using the liquid crystal aligning film of this invention, it is possible to manufacture the display element which shows high voltage retention and is excellent in reliability without contrast unevenness and display defect.

The liquid crystal display element having the liquid crystal aligning film of the present invention can be suitably used for TN type and STN type liquid crystal display elements as well as SH (Super Homeotropic) type and IPS (In-Plane Switching) type by appropriately selecting the liquid crystal to be used. It can also be used suitably for a liquid crystal display device of a mold, ferroelectric and antiferroelectric.

Moreover, the liquid crystal display element which has the liquid crystal aligning film of this invention can be used effectively for various apparatuses, For example, it is used for display apparatuses, such as a table calculator, a wristwatch, a table clock, a counting plate, a word processor, a personal computer, a liquid crystal television, etc. do.

Claims (6)

(a) A liquid crystal aligning film containing a polymer having an imide bond unit or a polymer having both an amic acid bond unit and an imide bond unit, wherein the total bond units of the imide bond unit and the amic acid bond unit in the polymer The percentage ratio of the number of imide bond units to the number is 30 to 100%, (b) the polarity of the surface tension is 10.2 to 15.3 dyn / cm The liquid crystal aligning film characterized by the above-mentioned. The liquid crystal aligning film of Claim 1 whose polymer is a polymer obtained by making tetracarboxylic dianhydride and diamine react, and the said tetracarboxylic dianhydride is alicyclic tetracarboxylic dianhydride. The liquid crystal aligning film of Claim 1 whose percentage ratio of the number of imide bond units with respect to the total number of bond units of the imide bond unit and the amic acid bond unit in a polymer is 30%-70%. 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-cyclo Butanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic Acid 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 acid dianhydride, 2,3,4,5-tetrahydrofuranthratecarboxylic dianhydride, bicyclo [2.2.2] -octo-7-ene- 2,3,5,6-tetracarboxylic dianhydride and cis-3,7-dibutylcycloocta-1,5-di -1,2,5,6-tetracarboxylic acid dianhydride at least one member selected from a liquid crystal alignment film of water. · The liquid crystal aligning film of Claim 1 containing the compound which has one or more epoxy groups in a molecule | numerator. The liquid crystal aligning film of Claim 1 is provided, The liquid crystal display element characterized by the above-mentioned.