KR101980637B1 - Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display device, and compound and polymer used for producing the same - Google Patents

Abstract

Disclosed is a liquid crystal aligning agent for obtaining a liquid crystal display element exhibiting a high voltage holding ratio under a high temperature environment and exhibiting low residual image characteristics.
A liquid crystal aligning agent containing at least one polymer selected from the group consisting of a polyamic acid obtained by reacting a tetracarboxylic acid dianhydride with a diamine and an imidized polymer thereof, ). ≪ / RTI >

Description

TECHNICAL FIELD [0001] The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film and a liquid crystal display element, and a compound and a polymer used in the production thereof. BACKGROUND ART [0002]

The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film and a liquid crystal display element, and a compound and a polymer used for their production.

BACKGROUND ART [0002] Liquid crystal displays are currently used in many devices such as televisions, car navigation systems, mobile phones, and the like, and are used in various environments as a necessity of everyday life. For example, in car navigation systems, use in a high temperature environment in summer, use for a long time, etc. is assumed. Therefore, it is desired to develop a liquid crystal display that exhibits high-quality display characteristics under a high-temperature environment and exhibits low-persistence characteristics with a small burn-in when a long time display is performed. Further, in order to obtain a liquid crystal display having such characteristics, development of a liquid crystal display device capable of maintaining a high voltage holding ratio even under a high temperature environment, less charge accumulation (residual DC) with respect to a direct current voltage, Is required. To develop such a liquid crystal display element, the enhancement of the performance of the liquid crystal alignment film, which greatly affects the voltage holding ratio and the residual DC characteristics, is key. On the other hand, an alignment film having a low residual image characteristic often increases the ion density in the liquid crystal, and it has been difficult to produce an alignment film exhibiting a good low residual image characteristic and a high voltage holding ratio.

In order to solve such problems, conventionally, various liquid crystal aligning agents for forming a liquid crystal alignment film have been proposed (for example, see Patent Document 1 and Patent Document 2). Patent Document 1 proposes a liquid crystal aligning agent comprising an imidized polymer obtained by reacting a diamine having two primary amino groups and nitrogen atoms other than the primary amino group in the molecule with a tetracarboxylic dianhydride. In Patent Document 2, a liquid crystal aligning agent containing a polyamic acid or the like obtained by the reaction of a diamine represented by 4,4'-diaminodiphenylamine with a tetracarboxylic acid dianhydride is used to measure a voltage It is proposed to improve the maintenance ratio and the low residual image characteristic.

Japanese Patent Application Laid-Open No. 10-104633 Japanese Patent No. 4052307

In recent years, there has been a growing demand for higher performance of liquid crystal displays and higher performance of liquid crystal display elements, and evaluation and selection of materials are performed under more stringent conditions. In view of this, there is a demand for a liquid crystal alignment film material exhibiting more excellent physical properties than conventional ones.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a liquid crystal aligning agent exhibiting a high voltage holding ratio under a high temperature environment and having a low afterimage characteristic, a novel compound useful as a component of the liquid crystal aligning agent, And a liquid crystal alignment film and a liquid crystal display device manufactured using the same.

DISCLOSURE OF THE INVENTION The present inventors have intensively studied in order to solve the problems of the prior art as described above, and as a result, they found that the above problems can be solved by including a polyamic acid having a specific structure derived from pyridine and an imidized polymer thereof in a liquid crystal aligning agent Thus, the present invention has been completed. Specifically, the following liquid crystal aligning agent, liquid crystal alignment film, liquid crystal display element, compound and polymer are provided by the present invention.

According to the present invention, there is provided a polyamic acid comprising at least one polymer selected from the group consisting of a polyamic acid obtained by reacting a tetracarboxylic dianhydride with a diamine, and an imidized polymer thereof, wherein the polymer has a structure represented by the following formula (1) And a liquid crystal alignment agent.

(Wherein (1), R ¹ is a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkyl group in an alkoxy group or a fluoro; m is an integer from 0 to 3, and when m is 2 or 3, a plurality of R ¹ Each independently having the above definition; " * "

According to the liquid crystal aligning agent of the present invention, it is possible to produce a liquid crystal alignment film for obtaining a liquid crystal display element exhibiting a high voltage holding ratio under a high temperature environment and having a low afterimage characteristic. Further, by producing a liquid crystal display element using the liquid crystal alignment film of the present invention, it is possible to maintain a high-quality display in a high-temperature environment in the liquid crystal display element, and to make it difficult to generate burn- have.

In the present invention, as the diamine, a compound represented by the following formula (2) may be used. More specifically, as A in the following formula (2), a compound which is a phenylene group or a substituted phenylene group, It is good to use.

(In the formula (2), A independently represents a single bond, a methylene group, an alkylene group having 2 to 6 carbon atoms, a phenylene group, a naphthylene group, a pyridylene group, a pyrimidinylene group or a triadienylene group, B is independently a monovalent group, -CO-, -COO- or -CO-NH-, R ¹ is a halogen atom, a cycloalkyl group having 1 to 6 carbon atoms An alkyl group, an alkoxy group or a fluoroalkyl group, m is an integer of 0 to 3, and when m is 2 or 3, plural R ^{1 s} each independently have the above definition).

According to the present invention, there is also provided a liquid crystal alignment film formed by the above liquid crystal aligning agent and a liquid crystal display device comprising the liquid crystal alignment film. These liquid crystal alignment films and liquid crystal display elements can be suitably used particularly for IPS liquid crystal display elements.

According to the present invention, there is provided a compound represented by the following formula (3). Further, a polymer (a polyamic acid and an imidized polymer thereof) obtained by reacting the compound with a tetracarboxylic dianhydride is provided.

(Wherein, in the formula (3), B is independently a single bond, -CO-, -COO- or -CO-NH-; R ¹ and R ² are each independently a halogen atom, An alkyl group, an alkoxy group or a fluoroalkyl group, m is an integer of 0 to 3, and when m is 2 or 3, plural R ¹ each independently have the above definition; It is an integer of 4, and if R ² is a plurality is present, they are R ² has the above definition, each independently).

(Mode for carrying out the invention)

The liquid crystal aligning agent of the present invention contains at least any polymer of a polyamic acid obtained by reacting a tetracarboxylic acid dianhydride with a diamine and an imidized polymer thereof. Hereinafter, the liquid crystal aligning agent of the present invention will be described in detail.

<Polyamic acid>

At least a part of the polyamic acid contained in the liquid crystal aligning agent of the present invention is represented by the following formula (1):

(Wherein (1), R ¹ is a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkyl group in an alkoxy group or a fluoro; m is an integer from 0 to 3, and when m is 2 or 3, a plurality of R ¹ Each independently have the above definition; &quot; * &quot;

Lt; / RTI &gt;

In R ¹ in the above formula (1), examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

Examples of the alkyl group having 1 to 6 carbon atoms may be linear or branched. Specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, An n-pentyl group, an isopentyl group, a neopentyl group, an n-hexyl group, and an isohexyl group.

As the fluoroalkyl group having 1 to 6 carbon atoms for R ¹ , there can be mentioned those in which at least one hydrogen atom of the above-mentioned alkyl group having 1 to 6 carbon atoms is substituted with a fluorine atom. Examples of the alkoxy group having 1 to 6 carbon atoms include those having an alkyl group having 1 to 6 carbon atoms bonded to an oxygen atom, and specific examples thereof include a methoxy group and an ethoxy group.

m is an integer of 0 to 3, preferably 0 to 2, and more preferably 0. When m is 2 or 3, plural R ^{1 s} may be the same or different.

The bonding position of the two NH groups in the pyridine ring of the formula (1) is not particularly limited, and examples thereof include a 2,6-position, a 2,5-position, a 2,4- Location, and so on. Of these, the bonding position of two NH groups is preferably a 2,6-position or a 2,4-position, more preferably a 2,6-position.

In order to obtain a polyamic acid having the structure represented by the above formula (1), for example, a tetracarboxylic acid dianhydride having a structure represented by the above formula (1) may be reacted with a diamine or a tetracarboxylic acid dianhydride And a diamine having a structure represented by the above formula (1). Of these, the latter is preferable.

[Tetracarboxylic acid dianhydride]

Examples of the tetracarboxylic acid dianhydride for synthesizing the polyamic acid in the present invention include aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, and aromatic tetracarboxylic dianhydride.

Specifically, examples of the aliphatic tetracarboxylic acid dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride and the like;

Examples of the alicyclic tetracarboxylic acid dianhydride include 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,3,3a, 4 , 5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [ (Tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-c] furan-1,3-dione, 3,9- -Tetrahydrofuran-2 &apos;, 5 ' -dione), 5- (2,5-dioxotetrahydro- 3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2: 3,5: 6-2 anhydride , 2,4,6,8-tetracarboxybicyclo [3.3.0] octane-2: 3,5: 6-2 anhydride, 2,4,6,8-tetracarboxybicyclo [3.3.0] octane- 2: 4,6: 8-2 anhydride, 4,9-dioxatricyclo [5.3.1.0 ^2,6 ] undecane-3,5,8,10-tetraone, 1S, 2S, 4R, 5R- Hexantate A carboxylic acid dianhydride, 1R, 2S, 4S, 5R- like cyclohexane tetracarboxylic acid dianhydride;

Examples of the aromatic tetracarboxylic acid dianhydride include pyromellitic dianhydride (PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-benzo Phenone tetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, and the like;

Other than the above, tetracarboxylic acid dianhydride described in JP-A-2010-97188 can be used. The tetracarboxylic acid dianhydrides may be used singly or in combination of two or more.

The tetracarboxylic acid dianhydride used for synthesizing the polyamic acid preferably contains an alicyclic tetracarboxylic acid dianhydride. In this case, the proportion of the alicyclic tetracarboxylic acid dianhydride is preferably from 10 to 100 mol%, more preferably from 50 to 100 mol%, based on the total amount of the tetracarboxylic acid dianhydride used in the synthesis of the polyamic acid , And still more preferably 80 to 100 mol%. By setting the thickness within the above range, a high voltage holding ratio can be maintained in a high temperature environment in a manufactured liquid crystal display element, and a low afterimage characteristic can be further improved.

[Diamine]

The diamine used for synthesizing the polyamic acid in the present invention preferably contains a compound represented by the following formula (2) (hereinafter also referred to as a diamine (D-1)).

(In the formula (2), A independently represents a single bond, a methylene group, an alkylene group having 2 to 6 carbon atoms, a phenylene group, a naphthylene group, a pyridylene group, a pyrimidinylene group or a triadienylene group, R ¹ and m each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, And R &^lt; ¹ &gt;

Examples of R ¹ in the formula (2) may be applied to the description of R ¹ in the formula (1) as it is. Further, regarding the bonding position of the NH group in the pyridine ring, the description of the above formula (1) can be applied as it is.

B is a single bond, -CO-, -COO- or -CO-NH-, and two B's in the formula (2) may be the same or different. Preferably, B is a single bond.

Examples of the alkylene group having 2 to 6 carbon atoms in A in the formula (2) may be linear or branched, and examples thereof include an ethylene group, a 1,3-propylene group, a 1,2-propylene group, , 4-butylene group and the like;

Examples of the phenylene group include a 1,3-phenylene group, a 1,4-phenylene group and the like;

Examples of the naphthylene group include 1,4-naphthylene group, 1,5-naphthylene group and the like;

Examples of the pyridyl group include a 2,4-pyridyl group, a 2,5-pyridyl group and the like;

Examples of the pyrimidinylene group include a 2,5-pyrimidinylene group and the like;

Examples of the triadienylene group include a 2,4-triadienylene group and the like;

Respectively. Examples of the substituent which these groups may have include halogen atoms such as a fluorine atom and a chlorine atom, cyano group, and the groups exemplified for R ¹ above.

Among them, A is preferably a substituted or unsubstituted phenylene group. That is, the diamine in the present invention preferably contains a compound represented by the following formula (3) (hereinafter also referred to as a diamine (D-1-1)). By including the diamine (D-1-1) as the diamine in the present invention, the interaction between the liquid crystal molecule and the benzene ring in the liquid crystal alignment film is easily induced, and the liquid crystal alignability is improved can do.

(In the formula (3), each of B independently represents a single bond, -CO-, -COO- or -CO-NH-; R ² each independently represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, alkoxy group or a fluoroalkyl group; r are, each independently, in the case of an integer of 0~4, R ² a plurality is present, they R ² has the above definition, each independently; R ^1, m has the formula R ^1, m and Im), respectively, as defined in (1).

R ^{2 in} the formula (3) includes the same groups as those exemplified for R ¹ in the formula (1).

As r, 0 to 2 are preferable, and 0 is more preferable.

In the benzene ring to be bonded to B, the bonding position of the primary amino group is not particularly limited, but is preferably 3-position or 4-position with respect to B, and more preferably 4-position.

Specific examples of the diamine (D-1) include 2,6-bis (4-aminoanilino) pyridine, 2,4-bis (4-aminoanilino) pyridine, 2,6- ) Pyridine, and 2,4-bis (3-aminoanilino) pyridine are preferable, and 2,6-bis (4-aminoanilino) pyridine is particularly preferable. By using at least one of these compounds, the structure of "-NH-pyridine ring -NH-" is introduced into the main chain of the polyamic acid. Accordingly, when a liquid crystal display element is manufactured using the liquid crystal alignment film formed, it can be considered that the voltage storage ratio characteristics and the low afterimage characteristics under the high temperature environment of the liquid crystal display element can be further enhanced.

As the diamine for synthesizing the polyamic acid in the present invention, only the diamine (D-1) represented by the formula (2) may be used, or other diamines may be used together with the diamine (D-1).

Examples of other diamines usable herein include aliphatic diamines, alicyclic diamines, aromatic diamines, diaminoorganosiloxanes, and the like, which are shown below. Specific examples thereof include aliphatic diamines such as 1,1-meta-xylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine and the like;

As the alicyclic diamine, for example, 1,4-diaminocyclohexane, 4,4'-methylenebis (cyclohexylamine), 1,3-bis (aminomethyl) cyclohexane and the like;

Examples of the aromatic diamine include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'- Diaminobiphenyl, 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl, 2,7'- Bis (4-aminophenoxy) phenyl] propane, 9,9-bis (4-aminophenyl) fluorene, 2, 4-diaminodiphenyl ether, (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, 4,4 '- (p- phenylenediisopropylidene ) Bisaniline, 4,4'- (m-phenylene diisopropylidene) bisaniline, 1,4-bis (4-aminophenoxy) benzene, 4,4'- , 2,4-diaminopyrimidine, 3,6-diaminoacrylidine, 3,6-diaminocarbazole, N-methyl-3, 6-diaminocarbazole, N, N'-bis (4-aminophenyl) benzidine, N, N'- Aminophenyl) -N, N'-dimethylbenzidine, 1,4-bis- (4-aminophenyl) -piperazine, 3,5- diaminobenzoic acid, dodecaneoxy- Oxy-2,4-diaminobenzene, pentadecanoxy-2,4-diaminobenzene, hexadecaneoxy-2,4-diaminobenzene, octadecanoxy- 2,5-diaminobenzene, pentadecaneoxy-2,5-diaminobenzene, hexadecaneoxy-2,5-diaminobenzene, octadecanoxy-2, 5-diaminobenzene, cholestanyloxy-3,5-diaminobenzene, cholestenyloxy-3,5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestenyloxy- 2,4-diaminobenzene, 3,5-diaminobenzoic acid cholestanyl, 3,5-diaminobenzoic acid cholestenyl, 3,5-diaminobenzoic acid ranostanyl, (4-aminobenzoyloxy) cholestane, 3,6-bis (4-aminophenoxy) cholestane, 4- (4'-trifluoromethoxybenzoyloxy) cyclohexyl-3,5-diaminobenzoate, Bis (4 - ((aminophenyl) methyl) phenyl) -4-butylcyclohexane, 1 (4'-trifluoromethylbenzoyloxy) cyclohexyl-3,5-diaminobenzoate, Heptylcyclohexane, 1,1-bis (4 - ((aminophenoxy) methyl) phenyl) -4-heptylcyclohexane, Diamino-N, N-diallylaniline, 4-aminobenzylamine, 3-aminobenzylamine, 3-aminobenzylamine, -Aminobenzylamine, 1- (2,4-diaminophenyl) piperazine-4-carboxylic acid, 4- (4-aminophenyl) piperidinyl) propane,? -Amino-? -Aminophenyl alkylene, and a compound represented by the following formula (A-1):

Wherein X ^I and X ^II are each a single bond, -O- or -COO-, R ^I is an alkanediyl group having 1 to 3 carbon atoms, a is 0 or 1, , b is an integer of 0 to 2, c is an integer of 1 to 20, and n is 0 or 1 (provided that a and b are not 0 at the same time)

And the like;

Examples of the diaminoorganosiloxane include 1,3-bis (3-aminopropyl) -tetramethyldisiloxane and the like, and diamines described in JP-A-2010-97188 Can be used.

Examples of the divalent group represented by -X ^I - (R ^I -X ^II ) _n - in the above formula (A-1) include an alkanediyl group having 1 to 3 carbon atoms, * -O-, * -COO- or * -O-CH ₂ CH ₂ -O- (provided that the bonding hand to which "*" is bonded is bonded to a diaminophenyl group). Specific examples of the group C 2 _{C 2} - ₁ - include a methyl group, an ethyl group, a n-propyl group, an n-butyl group, an n-pentyl group, N-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-hexadecyl group, n-hexadecyl group, an n-nonadecyl group, and an n-eicosyl group. The two primary amino groups in the diaminophenyl group are preferably in the 2,4-position or 3,5-position relative to the other groups.

Specific examples of the compound represented by the formula (A-1) include compounds represented by the following formulas (A-1-1) to (A-1-3).

The ratio of the diamine (D-1) to the total amount of the diamine is preferably from 10 to 100 mol% from the viewpoint of maintaining a high voltage holding ratio in a high temperature environment and further improving low residual image characteristics, , More preferably 50 to 100 mol%, and still more preferably 80 to 100 mol%.

&Lt; Molecular weight regulator &

In synthesizing the polyamic acid, the endmodified polymer may be synthesized using a suitable molecular weight regulator together with the tetracarboxylic dianhydride and the diamine as described above. By using such a polymer having a terminal modification type, the coating property (printing property) of the liquid crystal aligning agent can be further improved without impairing the effect of the present invention.

Examples of the molecular weight regulator include acid monoanhydrides, monoamine compounds, and monoisocyanate compounds. Specific examples thereof include acid anhydrides such as maleic anhydride, phthalic anhydride, itaconic anhydride, n-decylsuccinic anhydride, n-dodecylsuccinic anhydride, n-tetradecylsuccinic anhydride, n-hexadecylsuccinic anhydride My back;

As the monoamine compound, for example, aniline, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine and the like;

Examples of the monoisocyanate compound include phenyl isocyanate and naphthyl isocyanate.

The use ratio of the molecular weight regulator is preferably 20 parts by weight or less, more preferably 10 parts by weight or less, based on 100 parts by weight of the total amount of tetracarboxylic acid dianhydride and diamine to be used.

&Lt; Synthesis of diamine (D-1-1)

The diamine (D-1-1), which is a novel compound represented by the formula (3), can be suitably prepared by an organic chemical method. Specifically, when B in the formula (3) is a compound of a single crystal, for example, the compound (M-1) represented by the following formula is reacted with the compound (M-2) 3) (see Reaction Scheme (I) below).

(Wherein R ¹ , R ² , m and r are the same as defined for R ¹ , R ² , m and r in the formula (3), respectively).

Examples of the halogen atom of Y include a bromine atom, a chlorine atom, an iodine atom and a fluorine atom. Of these, bromine atoms are preferable from the viewpoint of reactivity.

The reaction of the reaction formula (I) is preferably carried out using a catalyst such as a palladium catalyst in the presence of a base, and it is preferable to carry out the reaction using a phosphine compound at that time.

Examples of the palladium catalyst used in the above reaction include tris (dibenzylidene) acetone dipalladium, Pd (PPh ₃ ) ₄ , PdCl ₂ (PPh ₃ ) ₂ , Pd (OAc) ₂ , tris ) Dipalladium chloroform complex and the like.

Examples of the phosphine compound include 2- (di-tert-butylphosphino) biphenyl, tri (tert-butyl) phosphine, tricyclohexylphosphine, 1,1'- Bis (di-tert-butylphosphino) -1,1'-binaphthyl, 2-di-tert-butylphosphino-2 ', 4', 6'-tri Isopropyl biphenyl, 2- (dicyclohexylphosphino) biphenyl, and the like.

Examples of the base include sodium carbonate, potassium carbonate, sodium hydrogencarbonate, sodium hydroxide, potassium hydroxide, barium hydroxide, sodium ethoxide, sodium tert-butoxide and sodium acetate.

The reaction temperature in Scheme (I) may be suitably set according to the reaction method, but is preferably 0 to 150 캜, more preferably 80 to 150 캜. Examples of the organic solvent used in the reaction include toluene and the like.

Subsequently, for the intermediate (M-3), reduction of the nitro group and reduction of the hydroxyl group are carried out under catalytic reduction conditions. As a result, a diamine (D-1-1), which is a compound represented by the formula (3), can be obtained (see the following reaction formula (II)).

(Wherein R ¹ , R ² , m and r are the same as defined for R ¹ , R ² , m and r in the formula (3), respectively).

Reaction of the reaction formula (II) is nickel, palladium-carbon, using, PtO _2, a catalyst such as Pd (OH) _2, and preferably carried out in -20~150 ℃, is more preferably performed at 0~120 ℃ . Examples of the solvent used in the reaction include tetrahydrofuran, toluene, N, N-dimethylformamide, N, N-dimethylacetamide and 1-methyl-2-pyrrolidone.

<Synthesis of polyamic acid>

The polyamic acid in the present invention can be obtained, for example, by reacting a diamine containing the compound represented by the formula (2), preferably the compound represented by the formula (3), with the tetracarboxylic acid dianhydride have. The ratio of the tetracarboxylic acid dianhydride and the diamine to be used in the synthesis reaction of the polyamic acid is preferably 0.2 to 2 equivalents of the tetracarboxylic acid dianhydride to the equivalent of 1 equivalent of the amino group of the diamine, To 1.2 equivalents is more preferable.

The synthesis reaction of the polyamic acid is preferably carried out in an organic solvent. The reaction temperature is preferably -20 ° C to 150 ° C, more preferably 0 ° C to 100 ° C. The reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours.

Examples of the organic solvent include non-protic polar solvents, phenol and derivatives thereof, alcohols, ketones, esters, ethers, halogenated hydrocarbons and hydrocarbons.

Specific examples of these organic solvents include non-protonic polar solvents such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, Butyrolactone, tetramethylurea, hexamethylphosphotriamide and the like;

As the phenol derivative, for example, m-cresol, xylenol, halogenated phenol and the like;

As the alcohol, for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 1,4-butanediol, triethylene glycol, ethylene glycol monomethyl ether and the like;

Examples of the ketone include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanol and the like;

As the ester, for example, ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, diethyl malonate and the like;

Examples of the ether include diethyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol n-butyl ether, ethylene glycol dimethyl ether, Ethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, tetraethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether acetate, Hydrofuran and the like;

As the halogenated hydrocarbon, for example, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene, o-dichlorobenzene and the like;

Examples of the hydrocarbons include hexane, heptane, octane, benzene, toluene, xylene, isoamyl propionate, isoamyl isobutyrate, and diisopentyl ether.

Among these organic solvents, at least one selected from the group consisting of an aprotic polar solvent and a group consisting of phenol and a derivative thereof (first group of organic solvents), or an organic solvent of the first group and at least one alcohol , A ketone, an ester, an ether, a halogenated hydrocarbon and a hydrocarbon (second group of organic solvents). In the latter case, the use ratio of the organic solvent of the second group is preferably 50% by weight or less, more preferably 40% by weight or less based on the total amount of the organic solvent of the first group and the organic solvent of the second group to be.

The amount (a) of the organic solvent used is preferably such that the total amount (b) of the tetracarboxylic acid dianhydride and the diamine is 0.1 to 50 wt% with respect to the total amount (a + b) of the reaction solution.

As described above, a reaction solution obtained by dissolving polyamic acid is obtained. The reaction solution may be directly supplied to the preparation of the liquid crystal aligning agent, or may be provided in the preparation of the liquid crystal aligning agent after isolating the polyamic acid contained in the reaction solution. Alternatively, after the isolated polyamic acid is purified, it may be added to the preparation of the liquid crystal aligning agent. The polyamic acid can be isolated and purified by a known method.

<Imidized Polymer>

The imidized polymer (polyimide) in the present invention can be obtained by imidizing the synthesized polyamic acid by dehydration ring closure. In this case, the reaction solution obtained by dissolving polyamic acid may be directly supplied to the dehydration ring-closing reaction, or the polyamic acid contained in the reaction solution may be isolated and then subjected to dehydration ring-closing reaction. Alternatively, the polyamic acid isolated may be purified and then subjected to a dehydration ring-closing reaction.

The polyimide in the present invention may be a completely imidized product in which all of the arboric acid structure of the polyamic acid which is a precursor thereof is subjected to dehydration ring closure and only a part of the arboric acid structure is subjected to dehydration ring closure, Partial imide cargo may also be used. The imide ratio of the polyimide in the present invention is preferably 30% or more, more preferably 50 to 99%, and still more preferably 65 to 99%. The imidization rate is a percentage of the ratio of the number of imide ring structures to the sum of the number of amide structure and the number of imide ring structure of polyimide. Here, a part of the imide ring may be an isoimide ring.

The dehydration ring-closure of the polyamic acid is preferably carried out by a method of heating the polyamic acid, or a method of dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydrating ring-closing catalyst to the solution, . Of these, the latter method is preferable.

In the method of adding the dehydrating agent and the dehydrating ring-closing catalyst to the solution of the polyamic acid, an acid anhydride such as acetic anhydride, propionic anhydride, or trifluoroacetic anhydride can be used as the dehydrating agent. The amount of the dehydrating agent to be used is preferably 0.01 to 20 mol based on 1 mol of the acid structure of the polyamic acid. As the dehydration ring-closing catalyst, for example, tertiary amines such as pyridine, collidine, lutidine and triethylamine can be used. The amount of the dehydration ring-closing catalyst to be used is preferably 0.01 to 10 mol based on 1 mol of the dehydrating agent to be used. Examples of the organic solvent used in the dehydration ring-closure reaction include the organic solvents exemplified for use in the synthesis of polyamic acid. The reaction temperature of the dehydration ring-closing reaction is preferably 0 to 180 캜, more preferably 10 to 150 캜. The reaction time is preferably 1.0 to 120 hours, more preferably 2.0 to 30 hours.

In this way, a reaction solution containing polyimide is obtained. This reaction solution may be provided as it is in the preparation of a liquid crystal aligning agent or may be provided in the preparation of a liquid crystal aligning agent after removing the dehydrating agent and the dehydration ring-closing catalyst from the reaction solution. Alternatively, after the polyimide is isolated, Or may be provided to the preparation of a liquid crystal aligning agent after purification of the isolated polyimide. These purification operations can be carried out according to a known method.

&Lt; Solution viscosity of polymer &gt;

The polyamic acid or imidized polymer (hereinafter also referred to as a specific polymer) in the present invention obtained as described above preferably has a solution viscosity of 20 to 800 mPa · s when the solution is a 10 wt% concentration solution , And more preferably 30 to 500 mPa · s. The solution viscosity (mPa 占 퐏) of the polymer is preferably 10% by weight or less, more preferably 10% by weight or less, based on the polymer Solution at 25 占 폚 using an E-type rotational viscometer.

<Other additives>

The liquid crystal aligning agent of the present invention contains a specific polymer as described above, but may contain other additives as required. Such other additives include, for example, other polymers other than the specific polymer, a compound having at least one epoxy group in the molecule (hereinafter referred to as "epoxy compound"), and a functional silane compound.

[Other Polymers]

Other polymers may be used to improve solution properties and electrical properties. Such another polymer is a polymer other than a specific polymer. For example, a polyamic acid (hereinafter referred to as "other polyamic acid") obtained by reacting a diamine containing no compound represented by the formula (2) with a tetracarboxylic acid dianhydride Polyamide, polysiloxane, cellulose derivative, polyacetal, polystyrene derivative, poly (styrene-butadiene-styrene) copolymer, and other polyimides obtained by dehydrating and ring- Phenylmaleimide) derivatives, poly (meth) acrylates, and the like. Of these, other polyamic acids or other polyimides are preferable, and other polyamic acids are more preferable. Examples of tetracarboxylic dianhydrides and diamines used for synthesizing other polyamic acids or other polyimides include compounds used for synthesizing specific polymers.

When the other polymer is added to the liquid crystal aligning agent, the blending ratio thereof is preferably 50% by weight or less, more preferably 0.1 to 40% by weight, and more preferably 0.1 to 30% by weight based on the total amount of the polymer in the liquid crystal aligning agent More preferable.

[Epoxy Compound]

Examples of the epoxy compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, Neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, trimethylol propane triglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl N, N, N ', N'-bis (N, N-diglycidylaminomethyl) cyclohexane, N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N, N-diglycidyl-benzylamine, N, N-diglycidylaminomethylcyclohexane, N, Glycidyl-cyclohexylamine, and the like.

When these epoxy compounds are added to the liquid crystal aligning agent, the blending ratio thereof is preferably 40 parts by weight or less, more preferably 0.1 to 30 parts by weight per 100 parts by weight of the total amount of the polymers contained in the liquid crystal aligning agent.

[Functional silane compound]

Examples of the functional silane compound include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2 -Aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxy Silane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N- Trimethoxysilyl-1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3 , 6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, methyl 9-trimethoxysilyl-3,6-diazononanoate, Benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl- N-phenyl-3-aminopropyltriethoxysilane, glycidoxymethyltrimethoxysilane, glycidoxymethyltriethoxysilane, 2-glycidoxyethyltrimethoxysilane, 2-glycidoxyethyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and the like.

When these functional silane compounds are added to the liquid crystal aligning agent, the mixing ratio thereof is preferably 2 parts by weight or less, more preferably 0.02 to 0.2 parts by weight based on 100 parts by weight of the total of the polymers.

[Organic solvents]

The liquid crystal aligning agent of the present invention is constituted by dissolving and containing a specific polymer and optionally other additives optionally mixed in an organic solvent.

Examples of the organic solvent used in the liquid crystal aligning agent of the present invention include N-methyl-2-pyrrolidone,? -Butyrolactone,? -Butyrolactam, N, N-dimethylformamide, Methylene-2-pentanone, ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxy propionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene Diethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, diethylene glycol dimethyl ether (ethylene glycol diethyl ether), ethylene glycol n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol- , Diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, di Isobutyl ketone, isoamyl propionate, isoamyl isobutyrate, di-isopentyl ether, ethylene carbonate, propylene carbonate, and the like. These may be used alone or in combination of two or more.

The solid concentration in the liquid crystal aligning agent (the ratio of the total weight of components other than the solvent of the liquid crystal aligning agent to the total weight of the liquid crystal aligning agent) is appropriately selected in consideration of viscosity, volatility, etc., By weight. That is, the liquid crystal aligning agent of the present invention is applied to the surface of the substrate as described later, and preferably is heated to form a coating film which becomes a liquid crystal alignment film or a liquid crystal alignment film. When the solid concentration is less than 1 wt% The film thickness of the coating film becomes too small to obtain a good liquid crystal alignment film. On the other hand, when the solid concentration exceeds 10% by weight, the film thickness of the coating film becomes excessively large, which makes it difficult to obtain a good liquid crystal alignment film, and further, the viscosity of the liquid crystal aligning agent is increased and the coating property may be deteriorated.

A particularly preferable range of the solid concentration is different depending on the method used when the liquid crystal aligning agent is applied to the substrate. For example, in the case of the spinner method, the solid content concentration is particularly preferably in the range of 1.5 to 6.0% by weight. In the case of the printing method, it is particularly preferable to set the solid concentration in the range of 3 to 9% by weight and the solution viscosity in the range of 12 to 50 mPa · s accordingly. In the case of the inkjet method, it is particularly preferable that the solid concentration is in the range of 1 to 5 wt%, and the solution viscosity is in the range of 3 to 15 mPa · s.

The temperature for preparing the liquid crystal aligning agent of the present invention is preferably 10 to 50 占 폚, more preferably 20 to 30 占 폚.

<Liquid Crystal Alignment Film and Liquid Crystal Display Device>

The liquid crystal alignment film of the present invention is formed by the above liquid crystal aligning agent. Further, the liquid crystal display element of the present invention comprises a liquid crystal alignment film formed by the above liquid crystal aligning agent. The operation mode of the liquid crystal display element may be applied to a horizontal alignment type such as an IPS type, a TN type, or an STN type, or to a vertically aligned type such as a VA type, It is particularly preferable to apply to the IPS type.

Hereinafter, a method of manufacturing a liquid crystal display element of the present invention will be described, and a method of manufacturing a liquid crystal alignment film of the present invention will be described. The liquid crystal display element of the present invention can be produced, for example, by the following steps (1) to (3). In the step (1), the substrate to be used differs depending on a desired operation mode. Steps (2) and (3) are common to each operation mode.

[Process (1): Formation of coating film]

First, the liquid crystal aligning agent of the present invention is coated on a substrate, and then a coated film is formed on the substrate by heating the coated surface.

(1-1) In the case of producing a TN type, STN type or VA type liquid crystal display device, two substrates on which a patterned transparent conductive film is formed are paired, and on the respective transparent conductive film forming surfaces, (Preferably preheating (prebaking) and firing (post baking) by applying the liquid crystal aligning agent of the liquid crystal aligning agent, preferably by an offset printing method, a spin coating method, a roll coater method or an inkjet printing method, ) To form a coating film.

Examples of the substrate include glass such as float glass and soda glass; A transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, and poly (alicyclic olefin) can be used.

As the transparent conductive film to be formed on one surface of the substrate, an ITO film made of NESA film (a registered trademark of PPG Corporation of the US) or indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ) made of tin oxide (SnO ₂ ) . In order to obtain a patterned transparent conductive film, for example, a method of forming a pattern by photoetching after forming a transparent conductive film without a pattern, a method of using a mask having a desired pattern for forming a transparent conductive film, and the like can do.

In the application of the liquid crystal aligning agent, a functional silane compound, a functional titanium compound or the like is added to the surface of the substrate surface on which the coating film is to be formed, in order to improve the adhesion between the substrate surface and the transparent conductive film and the coating film It is also possible to carry out the pre-treatment for applying the coating.

After applying the liquid crystal aligning agent, the coated surface is then preheated (prebaked) and further baked (post baked) to form a coated film. The prebaking conditions are, for example, 0.1 to 5 minutes at 40 to 120 占 폚, the postbaking conditions are preferably 120 to 300 占 폚, more preferably 150 to 250 占 폚, preferably 5 to 200 minutes , And more preferably 10 to 100 minutes. The film thickness of the formed coating film is preferably 0.001 to 1 mu m, more preferably 0.005 to 0.6 mu m.

(1-2) In the case of manufacturing an IPS type liquid crystal display element, on the surface of the substrate on which the transparent conductive film patterned in a comb shape is formed, and the opposite substrate on which the conductive film is not formed, And an orientation agent are then applied, and then each coating surface is heated to form a coating film. The material, the coating method, the heating conditions after application, the patterning method of the transparent conductive film, the pretreatment of the substrate, and the preferable film thickness of the coating film to be formed are the same as those in the above (1-1).

In both cases (1-1) and (1-2), a coating film to be an alignment film is formed by applying a liquid crystal aligning agent on a substrate and then removing the organic solvent. At this time, when the polymer contained in the liquid crystal aligning agent of the present invention is a polyamic acid or an imidized polymer having an imidazole ring structure and an arboric acid structure, the dehydration ring-closure reaction is further advanced by further heating after forming the coating film, Or may be a coated film.

[Process (2): rubbing treatment]

In the case of producing a TN type, STN type or IPS type liquid crystal display device, a coating film formed as described above is subjected to a rubbing treatment in which a cloth made of fibers such as nylon, rayon or cotton is rubbed in a predetermined direction . Accordingly, the alignment ability of the liquid crystal molecules is imparted to the coating film to form a liquid crystal alignment film.

It is also possible to use a process of changing the pretilt angle of a part of the liquid crystal alignment film by irradiating a part of the liquid crystal alignment film with ultraviolet rays to the liquid crystal alignment film and a process of changing a pretilt angle of a part of the liquid crystal alignment film after the resist film is formed on a part of the surface of the liquid crystal alignment film It is possible to improve the clock characteristic of the obtained liquid crystal display element by making the liquid crystal alignment film have different liquid crystal aligning ability for each region.

In the case of manufacturing a VA type liquid crystal display device, the coating film formed as described above can be directly used as a liquid crystal alignment film, but the rubbing treatment may be performed.

[Process (3): Construction of liquid crystal cell]

With respect to a pair of substrates on which liquid crystal alignment layers are formed as described above, the liquid crystal cells are constructed by opposing each other so that the rubbing directions of the liquid crystal alignment layers of the two substrates are orthogonal or anti-parallel. To construct a liquid crystal cell, for example, the following two methods can be used.

The first method is such that two substrates are opposed to each other with a gap (cell gap) interposed therebetween so that the respective liquid crystal alignment films face each other, and the peripheral portions of the two substrates are bonded together using a sealing agent. Next, liquid crystal is injected and filled in the cell gap defined by the surface of the substrate and the sealant, and then the injection port is sealed to construct a liquid crystal cell.

The second method is a so-called ODF (One Drop Fill) method. In this method, first, an ultraviolet-curing sealant, for example, is applied to a predetermined place on one of the two substrates on which the liquid crystal alignment film is formed, and furthermore liquid crystal is dropped on the liquid crystal alignment film side, And the other substrate is bonded so that the liquid crystal alignment film faces the other substrate. Subsequently, ultraviolet light is applied to the entire surface of the substrate to cure the sealant, thereby constructing the liquid crystal cell.

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

Examples of the liquid crystal include nematic liquid crystal and smectic liquid crystal. Among them, a nematic liquid crystal is preferable. Examples thereof include a cypher base liquid crystal, an agglutinative liquid crystal, a biphenyl liquid crystal, a phenyl cyclohexane liquid crystal, , Terphenyl-based liquid crystals, biphenylcyclohexane-based liquid crystals, pyrimidine-based liquid crystals, dioxane-based liquid crystals, bicyclooctane-based liquid crystals, quaternary type liquid crystals and the like. Further, to these liquid crystals, for example, cholesteric liquid crystals such as cholesteryl chloride, cholesteryl nonanoate and cholesteryl carbonate; Chiral agent sold under the trade names "C-15" and "CB-15" (Merck); p-decyloxybenzylidene-p-amino-2-methylbutyl cinnamate, and the like may be added and used.

Then, a polarizing plate is bonded to the outer surface of the liquid crystal cell so that its polarization direction coincides with or rises orthogonally to the rubbing direction of the liquid crystal alignment film formed on each substrate. Thus, a liquid crystal display element can be obtained. As the polarizing plate to be bonded to the outer surface of the liquid crystal cell, a polarizing plate in which a polarizing film called &quot; H film &quot; in which iodine is absorbed while polyvinyl alcohol is oriented in a stretched polyvinyl alcohol is sandwiched by a cellulose acetate protective film or a polarizing plate comprising H film itself .

The liquid crystal display element of the present invention can be effectively applied to various apparatuses and can be applied to various devices such as a clock, a portable game, a word processor, a notebook personal computer, a car navigation system, a camcorder, a PDA, , Various monitors, liquid crystal TVs, and the like.

(Example)

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

<Synthesis of diamine>

[Synthesis Example 1]

Compound (d-1) was synthesized according to Reaction Scheme 1 below. Further, if necessary, by repeating the scaling at the following scales, the required amount of the polyamic acid in the synthesis example was ensured.

In a 1 L three-necked flask equipped with a stirrer, a condenser and a thermometer, 33.1 g of 4-nitroaniline, 23.7 g of 2,6-dibromopyridine, 3.7 g of tris (dibenzylidene) acetone dipalladium, (Di-tert-butylphosphino) biphenyl, 28.8 g of sodium tert-butoxide and 500 mL of toluene were mixed and reacted by heating at 110 DEG C for 12 hours with stirring. After allowing to cool, the precipitate was recovered by filtration. Washed thoroughly with distilled water and ethanol, and dried to obtain 28.8 g (yield: 82%) of an intermediate.

Subsequently, 28.8 g of the intermediate, 5.0 g of Pd / C, 400 ml of tetrahydrofuran and 100 ml of ethanol were mixed in a 1 L three-necked flask equipped with a cooling tube and a thermometer under nitrogen atmosphere and stirred. 41 ml of hydrazine hydrate was added dropwise, and the mixture was stirred at 25 캜 for 1 hour and then heated and stirred at 70 캜 for 6 hours. After adding 100 ml of N, N-dimethylformamide to the reaction solution, Pd / C was removed by filtration through Celite. The filtrate and 300 ml of distilled water were mixed, and the precipitate was recovered by filtration. Washed thoroughly with distilled water and ethanol, and dried to obtain 18.4 g (yield: 77%) of the diamine compound (d-1).

<Synthesis of polyamic acid>

[Synthesis Example 2]

291 g (1.0 mol) of the compound (d-1) obtained in the above Synthesis Example 1 as a diamine and 2,2,3,4-cyclohexanetetracarboxylic acid dianhydride as a tetracarboxylic acid dianhydride were added to 2800 g of N- (1.0 mol) of butane tetracarboxylic acid dianhydride was dissolved and reacted at 40 占 폚 for 4 hours. Thus, a solution containing 15 wt% of polyamic acid (PA-1) was obtained. This solution was diluted to 10% by weight and the viscosity was measured to be 58 mPa · s.

[Synthesis Examples 3 to 8, Comparative Synthesis Examples 1 to 6]

(PA-2) to (PA-7) and (PAR-1) were obtained in the same manner as in Synthesis Example 1, except that the kinds of tetracarboxylic acid dianhydrides and diamines, To (PAR-6) was obtained.

In Table 1, abbreviations of tetracarboxylic acid dianhydrides and diamines are respectively as follows.

[Tetracarboxylic acid dianhydride]

T-1: 2,3,5-tricarboxycyclopentyl acetic acid dianhydride

T-2: pyromellitic acid dianhydride

T-3: 1,2,3,4-Cyclobutane tetracarboxylic acid dianhydride

[Diamine]

d-2: p-phenylenediamine

d-3: 1,3-bis (4-aminophenoxy) benzene

d-4: 4-Aminophenyl-4'-aminobenzoate

d-5: 4,4'-diaminodiphenylamine

d-6: 2,4-diaminodiphenylamine

&Lt; Preparation of liquid crystal aligning agent &

[Example 1]

? -Butyrolactone (BL), N-methyl-2-pyrrolidone (NMP) and butyl cellosolve (BC) were added to a solution containing the polyamic acid (PA-1) obtained in Synthesis Example 2 , And further 20 parts by weight of N, N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylmethane as an epoxy compound relative to 100 parts by weight of the total of 100 parts by weight of the polymer, A solution having a composition of BL: NMP: BC = 40: 40: 20 (weight ratio) and a solid content concentration of 4.0% by weight. This solution was filtered using a filter having a pore diameter of 1 mu m to obtain a liquid crystal aligning agent.

[Examples 2 to 7 and Comparative Examples 1 to 6]

A liquid crystal aligning agent was prepared in the same manner as in Example 1 except that the kinds of polyamic acid were changed to (PA-2) to (PA-7) and (PAR-1) to .

&Lt; Production of liquid crystal cell &

Each liquid crystal aligning agent of each of the prepared liquid crystal aligning agents of Examples 1 to 7 and Comparative Examples 1 to 6 was applied to the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film by using a spin coater, After the solvent was removed by heating (prebaking), the film was heated on a hot plate at 200 ° C for 10 minutes (post baking) to form a coating film having an average film thickness of 600 Å. The coating film was rubbed with a rubbing machine having a roll wrapped with a rayon cloth at a roll rotation speed of 1000 rpm, a stage moving speed of 25 mm / sec, and a hair embroidering length of 0.4 mm to give a liquid crystal aligning ability . Thereafter, ultrasonic cleaning was performed for 1 minute in ultrapure water, and then the substrate was dried in a 100 占 폚 clean oven for 10 minutes to obtain a substrate having a liquid crystal alignment film. This operation was repeated to obtain a pair of substrates (two substrates) each having a liquid crystal alignment film.

Next, after an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 5.5 占 퐉 was applied to the outer edge of any one of the pair of substrates having the liquid crystal alignment film, the liquid crystal alignment film surface was opposed to each other, Direction so that they are orthogonal to each other, thereby curing the adhesive. Subsequently, a nematic liquid crystal (MLC-2042, manufactured by Merck Ltd.) was filled between a pair of substrates from a liquid crystal injection port, and then a liquid crystal injection hole was sealed with an acrylic photo-curable adhesive to manufacture a liquid crystal cell.

&Lt; Evaluation of liquid crystal cell &

(1) Measurement of voltage holding ratio

A voltage of 5 V was applied to the liquid crystal cell prepared above at a temperature of 90 캜 for an application time of 60 microseconds and a span of 167 milliseconds and then a voltage maintenance ratio (VHR) after 167 milliseconds from the application of the release was measured. The measurement apparatus used was VHR-1 manufactured by Toyo Technica Co., Ltd. The case where the voltage holding ratio was 90% or more was evaluated as "good", and the case where the voltage holding ratio was less than 90% was evaluated as "poor".

(2) Measurement of residual DC

A rectangular wave of 30 Hz / 3 V added with an offset voltage of 3 V was applied to the liquid crystal cell prepared above at a temperature of 60 캜 for 120 minutes and the residual DC voltage (V) remaining in the liquid crystal cell immediately after the offset voltage of 3 V was cut off And measured by flicker erase method. When the residual DC voltage was 1 V or less, it was evaluated as &quot; Good &quot; and when the residual DC voltage was greater than 1 V, it was evaluated as &quot; Poor &quot;.

The results of the above (1) and (2) are shown in Table 2 below.

As shown in Table 2, all of the liquid crystal cells of Examples 1 to 6 exhibited good voltage holding characteristics in a high temperature environment and good residual DC characteristics. Among them, the liquid crystal cells of Examples 1 and 6 are characterized in that the voltage holding ratio at 90 캜 is as high as 94% or more, the measured residual DC voltage is 0.2 V or less, and the voltage- Both were particularly good. On the contrary, in Comparative Examples 1 to 6, the voltage holding ratio was as low as less than 90%, and the residual DC voltage showed a large value of 1.2 V or more.

Claims (7)

At least one polymer selected from the group consisting of a polyamic acid obtained by reacting a tetracarboxylic acid dianhydride with a diamine and an imidated polymer thereof,
The polymer is a liquid crystal aligning agent having a structure represented by the following formula (1)

(Wherein (1), R ¹ is a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkyl group in an alkoxy group or a fluoro; m is an integer from 0 to 3, and when m is 2 or 3, a plurality of R ¹ Each independently having the above definition; &quot; * &quot; The method according to claim 1,
Wherein the diamine comprises a compound represented by the following formula (2): &lt; EMI ID =

(In the formula (2), A independently represents a single bond, a methylene group, an alkylene group having 2 to 6 carbon atoms, a phenylene group, a naphthylene group, a pyridylene group, a pyrimidinylene group or a triadienylene group; B is independently a monovalent group, -CO-, -COO- or -CO-NH-, R ¹ is a halogen atom, a cycloalkyl group having 1 to 6 carbon atoms An alkyl group, an alkoxy group or a fluoroalkyl group, m is an integer of 0 to 3, and when m is 2 or 3, plural R ^{1 s} each independently have the above definition). 3. The method of claim 2,
The A is independently a phenylene group or a substituted phenylene group. A liquid crystal alignment film formed by the liquid crystal aligning agent according to any one of claims 1 to 3. A liquid crystal display element comprising the liquid crystal alignment film according to claim 4. delete delete