KR101999240B1 - Liquid crystal aligning agent, liquid crystal alignment film, liquid crystal display device, and manufacturing method for the liquid crystal alignment film - Google Patents

Abstract

(식 중, A는 단결합 또는 2가의 유기기이고, B는 2가의 유기기이고; R¹은 치환기이고, n은 0∼4의 정수임).Disclosed is a liquid crystal aligning agent which has a high liquid crystal alignment regulating force, is excellent in burn-in characteristics, and can give a liquid crystal display element excellent in electric characteristics.
(Solution) The liquid crystal aligning agent contains a polymer such as polyamic acid obtained by reacting a tetracarboxylic acid dianhydride with a diamine, wherein 60 mol% or more of the tetracarboxylic acid dianhydride is tetracarbon Acid dianhydride, and as the diamine, a compound represented by the following formula (1): < EMI ID =

(Wherein A is a single bond or a divalent organic group, B is a divalent organic group, R ¹ is a substituent, and n is an integer of 0 to 4).

Description

TECHNICAL FIELD [0001] The present invention relates to a liquid crystal alignment film, a liquid crystal alignment film, a liquid crystal display device, and a method of manufacturing a liquid crystal alignment film,

The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, a liquid crystal display element and a process for producing a liquid crystal alignment film. And more particularly to a liquid crystal aligning agent having a sufficient liquid crystal alignment regulating force, excellent burn-in characteristics, and capable of providing a liquid crystal display element having excellent electric characteristics.

In a liquid crystal display element, a liquid crystal alignment film is formed on a surface of a substrate in order to orient liquid crystal molecules in a predetermined direction with respect to the substrate surface. This liquid crystal alignment film is usually formed by a method (rubbing method) of rubbing the surface of the organic film formed on the substrate surface with a cloth such as rayon in one direction. However, when the formation of the liquid crystal alignment film is carried out by rubbing treatment, dust or static electricity is liable to be generated during the rubbing process, so that dust adheres to the surface of the alignment film to cause display defects. There is a problem that the circuit breakage of the TFT element occurs due to the generated static electricity, which causes a decrease in the product yield. Therefore, as another means of forming a liquid crystal alignment film, a photo alignment method in which a liquid crystal aligning ability is imparted to an organic thin film on a substrate by irradiating polarized or non-polarized radiation to the radiation-sensitive organic thin film formed on the substrate surface (See Patent Documents 1 to 4).

Examples of the liquid crystal display element include a liquid crystal display element having a liquid crystal cell of a longitudinal field type such as a TN type, an STN type and a VA type, and a liquid crystal display element such as IPS (In-Plane Switching) type or FFS (Fringe Field Switching) There is known a transverse electric field type liquid crystal display element in which an electrode is formed on one of a pair of substrates arranged opposite to each other and an electric field is generated in a direction parallel to the substrate (refer to Patent Documents 5 to 7). This transverse electric field type liquid crystal display element has a wider viewing angle characteristic than that of the liquid crystal display element of the conventional system, and high-quality display is possible. Since the liquid crystal display element of the transverse electric field system responds to the electric field only in the direction parallel to the substrate, the change of the refractive index in the major axis direction of the liquid crystal molecule is not a problem, and even when the viewing angle is changed, The change in the display color hue is small, and therefore, high-quality display can be performed irrespective of the time.

Japanese Patent Application Laid-Open No. 2003-307736 Japanese Laid-Open Patent Publication No. 2004-163646 Japanese Patent Application Laid-Open No. 2002-250924 Japanese Patent Application Laid-Open No. 2004-83810 U.S. Patent No. 5928733 Japanese Laid-Open Patent Publication No. 56-91277 Japanese Laid-Open Patent Publication No. 2008-46184 Japanese Laid-Open Patent Publication No. 2010-97188

In the transverse electric field type liquid crystal display element, when the liquid crystal alignment property is given to the liquid crystal alignment film, it is desired to use the photo alignment method in order to avoid the drawbacks of the above rubbing method. However, the liquid crystal aligning agent applicable to the photo alignment method tends to be insufficient in the liquid crystal alignment regulating force of the formed liquid crystal alignment film, and due to the insufficient liquid crystal alignment regulating force, when it is applied to a liquid crystal display element, Display failure may be seen.

In a liquid crystal display device manufactured by using a spacer of a type dispersing a bead having a small particle diameter, only a part of the bead is whitened at the time of black display. Since the bead is small particle size in the order of microns, if this white paper is the only one, it is not a problem in view of the viewer. However, in some cases, in addition to the whitening of the bead portion, there may be a case where a white line connecting the adjacent beads is seen. This white line may be recognized by the viewer as a display defect and should not exist on the screen. In this specification, disclination refers to such a display defect (linear white defect). It is presumed that this display defect occurs due to a lack of the liquid crystal alignment regulating force of the liquid crystal alignment film.

Disclination as described above has not been a serious problem in the degree of image resolution in the analog broadcasting era. However, in recent years, imaging technology and video transmission technology have made remarkable progress, and so-called high-vision broadcasting has begun to be digitalized even for home TV broadcasting. Further, along with this, the liquid crystal display element is further focussed with high definition, and the above deskewing is presently made. As a liquid crystal display element, it is required to realize reduction of destruction (that is, enhancement of liquid crystal alignment restraining force), compatibility with burn-in characteristics, electrical characteristics, and the like.

An object of the present invention is to provide a liquid crystal aligning agent capable of imparting a liquid crystal display element having a high liquid crystal alignment regulating force, excellent burning property, and excellent electric characteristics.

According to the present invention, the above objects and advantages of the present invention can be attained by a liquid crystal alignment layer containing at least one selected from the group consisting of a polyamic acid obtained by reacting a tetracarboxylic acid dianhydride with a diamine, an imidized polymer thereof, and a polyamic acid ester As a matter of fact,

Wherein at least 60 mol% of the tetracarboxylic acid dianhydride is a tetracarboxylic acid dianhydride having an alicyclic structure having a five-

Wherein the diamine comprises a compound represented by the following formula (1): < EMI ID =

(Wherein A is a single bond or a divalent organic group, B is a divalent organic group, R ¹ is a substituent, and n is an integer of 0 to 4).

The liquid crystal alignment film formed of the liquid crystal aligning agent of the present invention can impart a liquid crystal display element having a high liquid crystal alignment regulating force and good burn-in characteristics and electrical characteristics. In particular, the above effects can be exhibited while exhibiting advantageous effects of the transverse electric field system by the photo alignment method, and thus the present invention can be preferably applied to a liquid crystal alignment film of a liquid crystal display element of a transverse electric field system.

1 is an explanatory view showing a pattern of a comb-like conductive film.

(Mode for carrying out the invention)

Hereinafter, the present invention will be described in detail. The liquid crystal aligning agent of the present invention contains at least one member selected from the group consisting of a polyamic acid obtained by reacting a tetracarboxylic acid dianhydride with a diamine, an imidized polymer thereof, and a polyamic acid ester as a polymer component. Hereinafter, the polymer components contained in the liquid crystal aligning agent of the present invention, and other components arbitrarily blended as required, will be described.

[Polyamic acid]

(Tetracarboxylic acid dianhydride)

The tetracarboxylic acid dianhydride used in the synthesis of the polyamic acid (hereinafter also referred to as " specific polyamic acid ") in the present invention is preferably at least 60 mol% of the total amount of the tetracarboxylic acid dianhydride used in the reaction, (Hereinafter also referred to as " specific tetracarboxylic acid dianhydride ") having an alicyclic structure having an aromatic ring or more.

The alicyclic structure of the specific tetracarboxylic acid dianhydride is preferably an alicyclic structure in which the acid anhydride group is bonded is a five-membered ring or more, preferably a 5- to 8-membered ring, and more preferably a 5- to 7-membered ring. When the alicyclic structure to which an acid anhydride group is bonded is a polycyclic structure, the number of atoms constituting the ring in all the rings included in the polycyclic structure is 5 or more. The specific tetracarboxylic acid dianhydride may have an acid anhydride group bonded to an alicyclic structure and may have a chain hydrocarbon structure or an aromatic ring structure together with an alicyclic structure.

Specific examples of the specific tetracarboxylic acid dianhydride include 2,3,5-tricarboxycyclopentyl acetic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 1,3,3a, (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 [ 3,5,6-tricarboxy-2-carboxymethylnorbornane-2; 3,5; 6-2 anhydride, 2,4,6,8-tetracarboxybicyclo [3.3.0] , 6; 8-2 anhydride, 3-oxabicyclo [3.2.1] octane-2,4-dione-6-spiro- Dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 4,9-dioxatricyclo [5.3.1.0 ^2,6 ] undecane -3,5,8,10-tetraone, and the like.

The specific tetracarboxylic acid dianhydride preferably includes at least one of 2,3,5-tricarboxycyclopentylacetic acid dianhydride and 1,2,4,5-cyclohexanetetracarboxylic dianhydride , And more preferably 2,3,5-tricarboxycyclopentyl acetic acid dianhydride.

As the tetracarboxylic acid dianhydride used for synthesizing the specific polyamic acid in the present invention, only the above-mentioned specific tetracarboxylic acid dianhydride may be used, or other tetracarboxylic acid dianhydrides may be used in combination with it.

Examples of other tetracarboxylic acid dianhydrides which can be used herein include aliphatic tetracarboxylic acid dianhydrides, alicyclic tetracarboxylic dianhydrides (except those corresponding to the above specific tetracarboxylic dianhydrides), aromatic Tetracarboxylic acid dianhydride, and the like. Specific examples thereof include aliphatic tetracarboxylic acid dianhydrides such as butanetetracarboxylic dianhydride;

As the alicyclic tetracarboxylic acid dianhydride, for example, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride and the like of;

Examples of the aromatic tetracarboxylic acid dianhydride include 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, pyromellitic dianhydride, and the like, and also JP-A-2010-97188 Can be used.

As the tetracarboxylic acid dianhydride used for synthesizing the specific polyamic acid in the present invention, the aforementioned specific tetracarboxylic acid dianhydride is contained in an amount of 60 mol% or more based on the total amount of the tetracarboxylic acid dianhydride used in the synthesis , Preferably 80 mol% or more, and more preferably 90 mol% or more.

(Diamine)

The diamine used for the synthesis of the specific polyamic acid includes a compound represented by the formula (1) (hereinafter also referred to as "specific diamine").

Examples of the divalent organic group represented by A in the formula (1) include a divalent hydrocarbon group such as a chain hydrocarbon group, an alicyclic hydrocarbon group and an aromatic hydrocarbon group, and a carbon-carbon bond in the hydrocarbon group, COO-, -CO-, -NHCO-, -S-, -NH- and the like, and a divalent group in which a part or all of the hydrogen atoms of the hydrocarbon group is substituted with a halogen atom such as a fluorine atom And the like.

Herein, in the present specification, the term "chain hydrocarbon group" means a hydrocarbon group which does not contain a cyclic structure in its main chain and is composed of only a chain structure. However, the chain structure may be linear or branched. The "alicyclic hydrocarbon group" means a hydrocarbon group containing only the structure of an alicyclic hydrocarbon and not containing an aromatic ring structure as the ring structure. However, it is not always necessary to be constituted by only the structure of alicyclic hydrocarbons, and some of them include those having a chain structure. The term "aromatic hydrocarbon group" means a hydrocarbon group having an aromatic ring structure as a ring structure. However, it need not be constituted only of an aromatic ring structure, and a part thereof may contain a chain structure or a structure of an alicyclic hydrocarbon.

Specific examples of the bivalent hydrocarbon group include straight chain hydrocarbon groups such as methylene, ethylene, propanediyl, butanediyl, pentanediyl, hexanediyl, heptanediyl, octanediyl, An alkanediyl group having 1 to 10 carbon atoms such as a decanediyl group; An alkenyl group having 1 to 10 carbon atoms such as an ethynyl group, a propenyl group, and a butenyl group; An alkynyl group having 1 to 10 carbon atoms such as an ethynyl group and a propynyl group, and the like, and they may be linear or branched. Examples of the alicyclic hydrocarbon group include a cyclohexylene group, a group in which a part or all of hydrogen atoms contained in a cyclohexylene group are substituted with an alkyl group having 1 to 10 carbon atoms, and the like; Examples of the aromatic hydrocarbon group include a phenylene group, a group in which a part or all of the hydrogen atoms contained in the phenylene group are substituted with an alkyl group having 1 to 10 carbon atoms, and the like; Respectively.

A is preferably a single bond among them.

Examples of the divalent organic group of B include groups exemplified as the divalent organic group of A above or groups such as -C ₆ H ₄ -DC ₆ H ₄ - *, -C ₆ H ₄ -DC ₆ H ₁₀ - *, -C ₆ H _10- DC ₆ H ₄ - *, -C ₆ H ₁₀ -DC ₆ H ₁₀ - *, and the like. Wherein D represents a single bond, an alkyl group having 1 to 10 carbon atoms, -CH = CH-COO-, -OCO-CH = CH-, or a part or all of the hydrogen atoms of the alkyl group having 1 to 10 carbon atoms Lt; / RTI >&Quot; * " represents a bonding hand bonding to the primary amino group. In addition, the group "-C ₆ H ₄ -" or the group "-C ₆ H ₁₀ -" some or all of the hydrogen atoms is, may be substituted with an alkyl group having 1 to 10 carbon atoms.

Among the above, B is preferably a phenylene group, a cyclohexylene group, -C ₆ H ₄ -DC ₆ H ₄ - *, -C ₆ H ₄ -DC ₆ H ₁₀ - *, -C ₆ H ₁₀ -DC ₆ H ₄ -, -C ₆ H ₁₀ -DC ₆ H ₁₀ - *, or a group in which some or all of the hydrogen atoms contained in the ring structures of these groups are substituted with an alkyl group having 1 to 10 carbon atoms, -C ₆ H ₄ -DC ₆ H ₄ - * or a group in which some or all of the hydrogen atoms of the phenylene group in the phenylene group and -C ₆ H ₄ -DC ₆ H ₄ - * are replaced by an alkyl group having 1 to 10 carbon atoms More preferably a substituted group.

Examples of the substituent for R ¹ include an alkyl group having 1 to 10 carbon atoms, a halogen atom (such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom), and the like. n is an integer of 0 to 4, and is preferably 0.

Examples of the specific diamine include compounds represented by the following formulas (1-1) to (1-6), and the like. Among them, the specific diamine is preferably a compound represented by the following formula (1-1) or (1-6).

As the diamine used for synthesizing the specific polyamic acid in the present invention, only the above specific diamine may be used, or other diamines may be used in combination with the specific diamine.

Examples of other diamines usable herein include aliphatic diamines, alicyclic diamines, aromatic diamines, diaminoorganosiloxanes, and the like. Specific examples thereof include aliphatic diamines such as meta-xylene diamine, 1,3-propanediamine, tetramethylene diamine, pentamethylene diamine, hexamethylene diamine and the like;

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

As aromatic diamines, for example, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfide, 1,5-diaminonaphthalene, 2,2'-dimethyl Diaminobiphenyl, 4,4'-diamino-2,2'-bis (trifluoromethyl) biphenyl, 2,7-diaminofluorene, 4,4'-diamino Diphenyl ether, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 9,9- 4,4'- (m-tert-butylphenyl) hexafluoropropane, 2,2-bis (4-aminophenyl) hexafluoropropane, Bis (4-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) biphenyl, 2,6-diaminopyridine, 3,4 - diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminoacrylidine, 3,6-diaminocarbazole, N-methyl- , 6-diaminocarbazole, N-phenyl N, N'-bis (4-aminophenyl) benzidine, N, N'-bis (4-aminophenyl) -N, N'-dimethylbenzidine and the like;

As the diaminoorganosiloxane, for example, 1,3-bis (3-aminopropyl) -tetramethyldisiloxane and the like can be used, and diamines described in JP-A-2010-97188 can be used .

The diamine used for synthesizing the specific polyamic acid preferably contains 10 mol% or more, more preferably 30 mol% or more, of the compound represented by the formula (1) based on the total amount of the diamine used for the synthesis , And more preferably 50 mol% or more.

[Synthesis of polyamic acid]

The ratio of the tetracarboxylic dianhydride and the diamine used in the synthesis of the polyamic acid is preferably such that the ratio of the acid anhydride group of the tetracarboxylic dianhydride to the equivalent of the amino group contained in the diamine is 0.2 to 2 equivalents And more preferably 0.3 to 1.2 equivalents.

The synthesis reaction of the polyamic acid is preferably carried out in an organic solvent. Examples of the organic solvent include N, N-dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide, γ-butyrolactone, tetramethylurea, hexamethyl Aprotic polar solvents such as phosphotriamide; Phenol-based solvents such as phenol, m-cresol, xylenol, and halogenated phenol;

Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; But are not limited to, ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, diethyl oxalate, diethyl malonate, isoamyl propionate, ester;

N-propyl ether, ethylene glycol-n-propyl ether, ethylene glycol-n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, ethylene glycol monomethyl ether, diethylene glycol monobutyl ether, diisopentyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, Ethers such as 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 and tetrahydrofuran;

Halogenated hydrocarbons such as dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, trichloroethane, chlorobenzene and o-dichlorobenzene; And hydrocarbons such as benzene, toluene, xylene, and the like, and at least one selected from the above can be used.

The reaction temperature for the synthesis reaction of the polyamic acid is preferably -20 to 150 캜, more preferably 0 to 100 캜. The reaction time is preferably 0.5 to 24 hours, more preferably 2 to 12 hours.

[Imidized polymer]

The imidized polymer (hereinafter also referred to as " specific imidized polymer ") in the present invention can be synthesized by dehydrating and ring closure of a specific polyamic acid synthesized as described above. The specific imidized polymer may be a completely imidized product obtained by dehydrating and ring closure of the whole of the arid acid structure possessed by the polyamic acid and may be a partially imidized product in which only a part of the arid acid structure is subjected to dehydration ring closure, good.

The imidization ratio of the specific imidized polymer is preferably 5% or more, more preferably 10 to 60%, and even more preferably 15 to 50%. 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 a polyamic acid or a method of dissolving a polyamic acid in an organic solvent, adding a dehydrating agent and a dehydrating ring-closing catalyst to the solution, All. Of these, the latter method is particularly 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 use ratio of the dehydrating agent 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 use ratio of the dehydration ring-closing catalyst is preferably 0.01 to 10 mol per 1 mol of the dehydrating agent to be used. As the organic solvent used in the dehydration ring-closure reaction, the organic solvents exemplified above may be used for the synthesis of polyamic acid. The reaction temperature for 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.

[Polyamic acid ester]

The polyamic acid ester (hereinafter also referred to as "specific polyamic acid ester") in the present invention can be synthesized by reacting, for example, [I] the specific polyamic acid with a hydroxyl group-containing compound, a halide, , A method of reacting [II] tetracarboxylic acid diester with a diamine containing the specific diamine, [III] a method of reacting a tetracarboxylic acid diester dihalide with a diamine containing the specific diamine .

Examples of the hydroxyl group-containing compound used in the method [I] include alcohols such as methanol, ethanol and propanol; Phenols such as phenol and cresol, and the like. Examples of the halide include methyl bromide, ethyl bromide, stearyl bromide, methyl chloride, stearyl chloride, 1,1,1-trifluoro-2-iodoethane and the like, and the epoxy group-containing compound For example, propylene oxide. The tetracarboxylic acid diester used in the method [II] can be obtained by ring opening the above-exemplified tetracarboxylic dianhydride using the above-mentioned alcohols. However, 60 mol% or more of the total amount of the tetracarboxylic acid diester used in the synthesis is a tetracarboxylic acid diester having a 5-membered ring or more alicyclic structure.

The tetracarboxylic acid diester dihalide used in the method [III] can be obtained by reacting the tetracarboxylic acid diester thus obtained with a suitable chlorinating agent such as thionyl chloride. However, 60 mol% or more of the total amount of the tetracarboxylic acid diester dihalide used in the synthesis is a tetracarboxylic acid diester dihalide having an alicyclic structure of 5 or more rings. Further, the polyamic acid ester (P) may have only an amide ester structure, or may be a partial esterified product in which the amide structure and the amide ester structure coexist.

The polyamic acid, the imidized polymer and the polyamic acid ester obtained as described above preferably have a solution viscosity of 20 to 1,000 mPa · s and a viscosity of 30 to 800 mPa · s s of solution viscosity. The solution viscosity (mPa · s) of this polymer was determined by using a solution of these polymers (for example, γ-butyrolactone, N-methyl-2-pyrrolidone and the like) % Of the polymer solution at 25 占 폚 using an E-type rotational viscometer.

The weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) of the polyamic acid, the imidized polymer thereof and the polyamic acid ester obtained by the above synthesis is preferably 1,000 to 500,000, More preferably 300,000. The ratio (Mw / Mn) of the Mw to the polystyrene reduced number average molecular weight (Mn) measured by gel permeation chromatography (GPC) is preferably 15 or less, more preferably 10 or less. Within this molecular weight range, the stability of the liquid crystal aligning agent can be increased and satisfactory alignment properties in the obtained liquid crystal display element can be ensured.

<Other components>

The liquid crystal aligning agent of the present invention contains at least one kind of polymer selected from the group consisting of the specific polyamic acid, specific imidized polymer and specific polyamic acid ester (hereinafter also referred to as &quot; specific polymer &quot;) as an essential component However, other components may be contained as needed. Other components include, for example, other polymers other than the specific polymer, a compound having at least one epoxy group in the molecule (hereinafter also referred to as an &quot; epoxy compound &quot;), and a functional silane compound.

[Other Polymers]

These other polymers can be used for improvement of solution characteristics and electrical properties. Examples of the other polymer include polyamic acid other than the specific polyamic acid, imidized polymer other than the specific imidized polymer, polyamic acid ester other than the specific polyamic acid ester, polyester, polyamide, polysiloxane, cellulose derivative, Polystyrene and derivatives thereof, poly (styrene phenylmaleimide) and derivatives thereof, and poly (meth) acrylate, and at least one selected from the above can be used.

When other polymers are used, the use ratio thereof is preferably 90% by weight or less, more preferably 60% by weight or less, based on the sum of the polymer components (the total of the specific polymer and other polymers, , And more preferably 30 wt% or less.

[Epoxy Compound]

The epoxy compound can be used for the purpose of improving the adhesiveness with the substrate surface in the liquid crystal alignment film and the electric characteristics. 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, and at least one selected from these may be used.

When the epoxy compound is used, the amount of the epoxy compound is preferably 40 parts by weight or less, more preferably 0.1 to 30 parts by weight, based on 100 parts by weight of the total amount of the polymer.

[Functional silane compound]

The functional silane compound can be used for the purpose of improving the printability of a liquid crystal aligning agent or the like. 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, and at least one selected from the above can be used.

When the functional silane compound is used, the use 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 amount of the polymer.

&Lt; Preparation of liquid crystal aligning agent &

The liquid crystal aligning agent of the present invention is constituted as a solution phase composition obtained by dissolving the above specific polymer and optionally other components optionally used 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, and the like isoamyl isobutyrate, di-isopentyl ether, ethylene carbonate, propylene carbonate, may be used one or more selected from these into.

The solid concentration in the liquid crystal aligning agent of the present invention (the ratio of the total weight of components other than the solvent in the liquid crystal aligning agent to the total weight of the liquid crystal aligning agent) is appropriately selected in consideration of viscosity, volatility, etc., 1 to 10% by weight. By setting the solid concentration in this range, it is preferable to form a liquid crystal alignment film having a suitable film thickness with good coating properties.

A particularly preferable range of the solid concentration is different depending on the method used when the liquid crystal aligning agent is applied on the substrate. For example, in the case of the spinner method, it is particularly preferable that the solid content concentration is in the range of 1.5 to 4.5 wt%. In the case of the printing method, it is particularly preferable that the solid concentration is in the range of 3 to 9% by weight. In the case of the ink-jet method, it is particularly preferable that the solid concentration is in the range of 1 to 5 wt%. 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.

&Lt; Liquid Crystal Alignment Film and Manufacturing Method Thereof &

The liquid crystal alignment film of the present invention can be produced using the liquid crystal aligning agent of the present invention and is preferably produced by a method including the following steps (1) and (2).

(1) a step (coating step) of applying a liquid crystal aligning agent of the present invention on a substrate to form a coating film; and (2) a step of irradiating light onto the coating film (light irradiation step).

(1) Coating process

When the liquid crystal aligning agent of the present invention is applied to a liquid crystal display element having a liquid crystal cell of the past system type, two substrates on which a patterned transparent conductive film is formed are made into a pair, , The liquid crystal aligning agent of the present invention is applied to form a coating film. On the other hand, when the liquid crystal aligning agent of the present invention is applied to a liquid crystal display element having a liquid crystal cell of a transverse electric field system, a substrate having a pair of electrodes patterned in a comb- And the liquid crystal aligning agent of the present invention is coated on one surface of the comb-like electrode and one surface of the opposite substrate to form a coating film.

Examples of the conventional system and the transverse electric system include glass such as float glass and soda glass; A transparent substrate made of plastic such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, or the like can be used. As the transparent conductive film, for example, an ITO film made of In ₂ O ₃ -SnO ₂ , a NESA (registered trademark) film made of SnO ₂ , or the like can be used. As the metal film, for example, a film made of a metal such as chromium can be used. The patterning of the transparent conductive film and the metal film includes, for example, a method of forming a pattern by a photo-etching method or a sputtering method after forming a pattern-free transparent conductive film, a method of using a mask having a desired pattern in forming a transparent conductive film And so on.

A functional silane compound, titanate or the like is coated on the substrate and the electrode in order to improve the adhesion between the substrate and the electrode and the coating film upon application of the liquid crystal aligning agent onto the substrate, Or may be carried out prior to the processing.

The application of the liquid crystal aligning agent onto the substrate can be preferably carried out by an appropriate application method such as an offset printing method, a spin coating method, a roll coater method, or an inkjet printing method. After the application, the coated surface can be formed by preheating (prebaking) the coating surface and then baking (postbaking). The prebaking condition is, for example, a heating time of 0.1 to 5 minutes at a heating temperature of 40 to 120 캜. The post baking condition is, for example, a heating time of 120 to 300 캜, preferably 150 to 250 캜, for example, 5 to 200 minutes, preferably 10 to 100 minutes. The film thickness of the coated film after post-baking is preferably 0.001 to 1 mu m, more preferably 0.005 to 0.5 mu m.

(2) Light irradiation process

In this step, a coating film formed on a substrate is irradiated with a radiation of polarized light or non-polarized light to impart a liquid crystal aligning ability to the coating film to form a liquid crystal alignment film. As the light to be irradiated here, for example, ultraviolet rays including visible light having a wavelength of 150 to 800 nm, visible light, or the like can be used. Among them, ultraviolet rays containing light having a wavelength of 200 to 400 nm are preferable.

When the radiation used for light irradiation is polarized (linearly polarized light or partial polarized light), it may be irradiated from an oblique direction to give a pretilt angle even when irradiated from a perpendicular direction to the coated film surface. On the other hand, in the case of irradiating non-polarized radiation, it is necessary to conduct irradiation from the oblique direction with respect to the coated film surface.

As the light source to be used, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an Hg-Xe lamp and an excimer laser can be used. The ultraviolet ray of the above-mentioned preferable wavelength range can be obtained by a means for using the light source together with a filter, a diffraction grating, or the like. The dose of light is preferably 100 J / m 2 or more and less than 50,000 J / m 2, more preferably 500 to 20,000 J / m 2, and still more preferably 1,000 to 10,000 J / m 2.

<Liquid crystal display element>

The liquid crystal display element of the present invention can be manufactured as follows using a substrate having a liquid crystal alignment film formed as described above.

First, a pair of substrates on which a liquid crystal alignment film is formed as described above is prepared, and a liquid crystal cell having a configuration in which liquid crystal is sandwiched between the pair of substrates is manufactured. To produce a liquid crystal cell, for example, the following two methods can be used.

As a first method, a pair of substrates are disposed to face each other with a gap (cell gap) interposed therebetween such that the liquid crystal alignment layers of the respective substrates are opposed to each other, the periphery of the pair of substrates is bonded using a sealant, A liquid crystal is injected and filled in a cell gap defined by a liquid crystal cell, and then an injection port is sealed to manufacture a liquid crystal cell.

As a second method, for example, an ultraviolet curable sealant is applied to a predetermined place on one of the two substrates on which a liquid crystal alignment film is formed, and further liquid crystal is dropped to a predetermined number of places on the liquid crystal alignment film surface The liquid crystal is spread on the substrate surface and then the ultraviolet light is irradiated to the entire surface of the substrate or only the portion to which the sealing agent is applied to cure the sealing agent, . &Lt; / RTI &gt; This second method is a so-called ODF (One Drop Fill) method.

In either case, it is preferable that the liquid crystal cell is heated to a temperature at which the liquid crystal assumes an isotropic phase, and then the liquid crystal cell is gradually cooled to room temperature to remove the flow alignment at the time of filling the liquid crystal.

Then, the polarizing plate is brought into contact with the outer surface of the liquid crystal cell to obtain the liquid crystal display element of the present invention. Here, a desired liquid crystal display element can be obtained by appropriately adjusting the angle between the polarized direction of the linearly polarized light irradiated and the angle between each substrate and the polarizing plate in a pair of substrates on which the liquid crystal alignment film is formed.

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

As the liquid crystal, for example, nematic liquid crystal, smectic liquid crystal and the like can be used.

In the case of producing a TN type liquid crystal cell or an STN type liquid crystal cell, a nematic liquid crystal having positive dielectric anisotropy is preferable, and examples thereof include biphenyl type liquid crystal, phenyl cyclohexane type liquid crystal, ester type liquid crystal, Based liquid crystal, biphenylcyclohexane-based liquid crystal, pyrimidine-based liquid crystal, dioxane-based liquid crystal, bicyclooctane-based liquid crystal, quaternary liquid crystal and the like. Further, cholesteric liquid crystals such as cholesteryl chloride, cholesteryl nonanoate, and cholesteryl carbonate; Chiral agents such as those sold under the trade names "C-15" and "CB-15" (Merck); p-decyloxybenzylidene-p-amino-2-methylbutyl cinnamate and the like may be further added to the liquid crystal.

On the other hand, when a vertically aligned liquid crystal cell is manufactured, a nematic liquid crystal having a negative dielectric anisotropy is preferable. For example, a dicyanobenzene liquid crystal, a pyridazine liquid crystal, a heptbase liquid crystal, A liquid crystal, a biphenyl-based liquid crystal, a phenylcyclohexane-based liquid crystal, or the like can be used.

Examples of the polarizing plate used for the outside of the liquid crystal cell include 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 state is sandwiched by a cellulose acetate protective film or a polarizing plate made of H film itself have. The liquid crystal display element of the present invention manufactured in this way is excellent in various properties such as display characteristics and electrical characteristics.

[Example]

Hereinafter, the present invention will be described more specifically by way of examples, but the present invention is not limited to these examples.

In the following Synthesis Examples, the imidization ratio of the polymer and the solution viscosity of the polymer solution were measured by the following methods.

[Imidization Rate of Polymer]

The polyimide-containing solution was poured into pure water, and the obtained precipitate was sufficiently dried under reduced pressure at room temperature, and dissolved in deuterated dimethyl sulfoxide. ¹ H-NMR was measured at room temperature using tetramethylsilane as a reference material. From the obtained ¹ H-NMR spectrum, the imidation rate was obtained using the following equation (1): &lt; EMI ID =

Imidization rate [%] = {(1-A ¹ ) / (A ² x?)} 100 ... (One)

(In the formula (1), A ¹ is the peak area derived from the proton of the NH group near the chemical shift of 10 ppm, A ² is the peak area derived from the other proton, and α is the peak area derived from the proton The ratio of the number of other protons to one proton in the NH group).

[Solution viscosity of polymer solution]

The solution viscosity (mPa s) of the polymer solution was measured at 25 캜 using an E-type rotational viscometer.

&Lt; Synthesis of specific polymer (polyamic acid) &gt;

[Synthesis Example PA-1]

(0.01 mole) of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride as tetracarboxylic acid dianhydride and 2.54 g (0.01 mole) of the compound represented by the above formula (1-1) as a diamine were dissolved in N-methyl- -Pyrrolidone (NMP), and the mixture was reacted at 40 DEG C for 3 hours to obtain 31.8 g of a solution containing 15 wt% of polyamic acid (PA-1). The solution viscosity of this polyamic acid solution was 65 mPa · s.

[Synthesis Examples PA-2 to PA-7 and pa-1 to pa-2]

A polyamic acid solution was obtained in the same manner as in Synthesis Example PA-1 except that tetracarboxylic acid dianhydride and diamine of the kind and amount shown in Table 1 below were used. Viscosity of each solution obtained is shown in Table 1 below.

 In Table 1, the tetracarboxylic dianhydrides and diamines have the following meanings respectively.

[Tetracarboxylic acid dianhydride]

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

t-2: (1S, 2S, 4R, 5R) -cyclohexanetetracarboxylic acid dianhydride

t-3: pyromellitic dianhydride

[Diamine]

d-1: The compound represented by the above formula (1-1)

d-2: Compound represented by the above formula (1-3)

d-3: Compound represented by the above formula (1-4)

d-4: A compound represented by the following formula (d-4)

d-5: Compound represented by the following formula (d-5)

[Synthesis Example PI-1]

15.9 g of N-methyl-2-pyrrolidone, 0.8 g of pyridine and 1.0 g of acetic anhydride were added to the polyamic acid solution obtained in the same manner as in Synthesis Example PA-1, followed by dehydration cyclization under stirring at 120 DEG C for 4 hours Followed by heating to obtain a solution containing polyimide (PI-1). The imidization rate of the polyimide (PI-1) contained in this solution was 47%.

[Synthesis Example sp-1]

(0.01 mol) of a compound represented by the following formula (DC-1) as a dicarboxylic acid, 2.02 g (0.01 mol) of a compound represented by the following formula (DE-3) as a diepoxy compound, Pyrrolidone was added to the reaction mixture and the mixture was stirred at 140 占 폚 for 6 hours to carry out a reaction to obtain a solution containing the polymer (sp-1).

[Synthesis Example PA-8, PA-9]

A polyamic acid solution was obtained in the same manner as in Synthesis Example PA-1 except that tetracarboxylic acid dianhydride and diamine of the kind and amount shown in Table 2 were used. Viscosity of each solution obtained is shown in Table 2 below.

 In Table 2, tetracarboxylic dianhydrides and diamines have the following meanings respectively.

[Tetracarboxylic acid dianhydride]

t-4: (1R, 2S, 4S, 5R) -cyclohexanetetracarboxylic acid dianhydride

[Diamine]

d-6: Compound represented by the above formula (1-6)

[Synthesis Example PI-2, PI-3]

Except that a polyamic acid solution obtained in the same manner as in Synthesis Example PA-2 was used for Synthesis Example PI-2 and a polyamic acid solution obtained in the same manner as in Synthesis Example PA-3 for Synthesis Example PI-3 was used A solution containing polyimide was obtained in the same manner as in Example PI-1. The imidization rate of the polyimide (PI-2) contained in the solution of the synthesis example PI-2 was 35%, the imidization rate of the polyimide (PI-3) contained in the solution of the synthesis example PI- Respectively.

[Example 1]

&Lt; Preparation of liquid crystal aligning agent &

N-methyl-2-pyrrolidone (NMP) and butyl cellosolve (BC) were added to a solution containing polyamic acid (PA-1) synthesized in Synthesis Example PA-1 as polyamic acid, 3.5% by weight and a solvent composition of NMP / BC = 70/30 (weight ratio), and filtered through a filter having a pore size of 0.2 탆 to prepare a liquid crystal aligning agent.

<Evaluation of Voltage Conservation Rate>

(1) Manufacture of liquid crystal display device for evaluation of voltage holding ratio

A glass substrate having a metal electrode made of chrome in a comb shape and having a metal electrode on one side and an opposing glass substrate on which no electrode is formed are formed as a pair, Was prebaked on a hot plate at 80 DEG C for 1 minute and then heated in an oven where the inside was replaced with nitrogen at 200 DEG C for 1 hour (post baking) to form a film having a thickness of 0.1 mu m Was formed. Subsequently, polarizing ultraviolet rays of 5000 J / m 2 containing a bright line of 313 nm were irradiated from the normal direction of the substrate to the surface of these coating films by using Hg-Xe lamps and Glan Taylor prisms respectively to obtain a pair of substrates on which liquid crystal alignment films were formed .

An epoxy resin adhesive containing aluminum oxide spheres having a diameter of 3.5 占 퐉 was applied to the periphery of the surface having one liquid crystal alignment film in the above substrate by screen printing and then the surfaces of the liquid crystal alignment films of the pair of substrates were opposed to each other, The optical axes were superimposed on each other so that the direction of projection on the substrate surface was parallel to each other, and the adhesive was thermally cured at 150 DEG C for 1 hour. Subsequently, a liquid crystal MLC-7028 manufactured by Merck Ltd. was filled in the gap between the substrates from the liquid crystal injection port, and then the liquid crystal injection port was sealed with an epoxy adhesive. Further, in order to remove the flow orientation at the time of injecting the liquid crystal, it was heated at 120 占 폚 for 10 minutes and then slowly cooled to room temperature. Next, the polarizing plate is bonded to both outer sides of the substrate so that the polarizing directions thereof are orthogonal to each other and the polarizing direction of either polarizing direction is parallel to the direction in which the optical axis of the polarized ultraviolet ray of the liquid crystal alignment film is projected to the substrate surface, A liquid crystal display element for evaluation was manufactured.

(2) Evaluation of Voltage Conservation Rate

A voltage of 5 V was applied to the liquid crystal display device manufactured at 60 캜 at an application time of 60 microseconds and a span of 167 milliseconds and then the voltage maintenance ratio after 167 milliseconds after the application was released was measured Quot; VHR-1 &quot;. (?) When the value was 98% or more, the voltage holding ratio was "good (?)", The voltage holding ratio was " . The evaluation results are shown in Table 3 below.

<Evaluation of burn-in characteristics>

(1) Preparation of liquid crystal display element for evaluation of burn-in characteristics

In the above-mentioned &quot; manufacture of liquid crystal display element for evaluation of voltage holding ratio &quot;, as a glass substrate, a glass substrate having two lines of comb-shaped conductive film patterns made of chrome and a glass substrate having no conductive film were used as a pair, A liquid crystal display device was produced in the same manner as in &quot; Production of liquid crystal display device for voltage-holding ratio evaluation &quot; except that the liquid crystal aligning agent was applied on the conductive film of the substrate having the conductive film and on one side of the other substrate. Fig. 1 is a schematic view showing the electrode pattern configuration on the glass substrate. In the following, the two types of conductive film patterns of the liquid crystal display element manufactured as described above will be referred to as "electrode A" and "electrode B", respectively.

(2) Evaluation of burn-in characteristics

The liquid crystal display device prepared above was placed under an environment of 25 占 폚 and 1 atmospheric pressure, and a voltage of 3.5 V AC and 5 V DC voltage was applied to the electrode A for 2 hours without applying voltage to the electrode B. Immediately thereafter, a voltage of 4 V of AC was applied to both the electrode A and the electrode B. The time from when the voltage of 4 V of alternating current was started to the time when it became impossible to visually confirm the difference in light transmittance between the electrodes A and B was measured. The burn-in characteristic is "possible" when the burn-in characteristic is "good" (⊚) when the time is less than 15 seconds, less than 100 seconds when the burn-in characteristic is " . The evaluation results are shown in Table 3 below.

<Evaluation of Disclination>

(1) Manufacture of liquid crystal display device for evaluation of disclination

In the above-mentioned &quot; Production of liquid crystal display element for evaluation of voltage holding ratio &quot;, the diameter of the aluminum oxide spheres contained in the epoxy resin adhesive applied by screen printing was changed from 3.5 탆 to 5.5 탆, (HAYABEADS, manufactured by Hayakawa Rubber Co., Ltd.) having a diameter of 5 to 5.5 mu m was dispersed in an amount of about 20 to 30 per 10 cm &lt; 2 &gt;, and then a pair of substrates were opposed to each other. Manufacture of display element &quot;, a liquid crystal display element for a disclination evaluation was produced.

(2) Evaluation of disclination

The liquid crystal display obtained above was placed on a backlight in a voltage-unapplied state, and a 3 cm square area near the center of the display area was observed with a microscope at a magnification of 20 times. (?) "When the number of disclinations (line-like white defects) generated between the bead spacers was zero was defined as" good (?) " Was evaluated as &quot; defective (x) &quot;. The evaluation results are shown in Table 3.

[Examples 2 to 8 and Comparative Examples 1 to 3]

A liquid crystal aligning agent was prepared and evaluated in the same manner as in Example 1 except that the kind and amount of the polymer used were changed as shown in Table 3, respectively. The evaluation results are shown in Table 3, respectively. In Examples 6 and 7, additives were added as shown in Table 3 at the time of preparing the liquid crystal aligning agent. The numerical value in the weight part of the additive indicates the orientation ratio relative to the total amount of 100 parts by weight of the polymer component contained in the liquid crystal aligning agent.

In Table 3, abbreviations of additives are as follows.

[additive]

e-1: N, N, N ', N'-tetraglycidyl-4,4'-diaminodiphenylmethane

[Examples 9 to 20]

A liquid crystal aligning agent was prepared and evaluated in the same manner as in Example 1, except that the type and amount of the polymer used were changed as shown in Table 4, respectively. The evaluation results are shown in Table 4, respectively. In Examples 10, 11, 13, 14, 16, 17, 19, and 20, additives were added as shown in Table 4 at the time of preparing the liquid crystal aligning agent. The numerical value in the weight part of the additive indicates the orientation ratio relative to the total amount of 100 parts by weight of the polymer component contained in the liquid crystal aligning agent.

In Table 4, the abbreviations of the additives are as follows.

[additive]

e-2: N, N, N ', N'-tetraglycidyl-m-xylylenediamine

As shown in Table 3 and Table 4, in the examples, a liquid crystal display element having less occurrence of deskewing, high voltage holding ratio, and small burn-in was obtained. On the other hand, in the liquid crystal display devices of Comparative Examples 1 and 2, many disclinations were observed, and in the liquid crystal display device of Comparative Example 3, the voltage holding ratio was low.

Claims (6)

As a liquid crystal aligning agent containing at least one member selected from the group consisting of a polyamic acid obtained by reacting a tetracarboxylic acid dianhydride with a diamine, an imidized polymer thereof, and a polyamic acid ester,
Wherein at least 60 mol% of the tetracarboxylic acid dianhydride is a tetracarboxylic acid dianhydride having an alicyclic structure having a five-
A liquid crystal aligning agent characterized in that the diamine comprises a compound represented by the following formula (1)

(Wherein A is a single bond or a divalent organic group, B is a divalent organic group, R ¹ is a substituent, and n is an integer of 0 to 4). The method according to claim 1,
Wherein at least 60 mol% of the tetracarboxylic acid dianhydride is at least one of 2,3,5-tricarboxycyclopentyl acetic acid dianhydride and 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, . The method according to claim 1,
A liquid crystal aligning agent further containing, as an additive component, a compound having at least one epoxy group in the molecule. 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. A method for manufacturing a liquid crystal display device, comprising the steps of: applying a liquid crystal aligning agent according to any one of claims 1 to 3 on a substrate to form a coating film;
And irradiating the coating film with light.

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