Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element using the same

Abstract

Provided is a liquid crystal aligning agent that can obtain a liquid crystal alignment film having good liquid crystal alignment properties and that increases the sensitivity margin. A liquid crystal aligning agent characterized by containing at least one polymer selected from the group consisting of a polyamide acid and a polyimide obtained by imidizing the polyamide acid, the polyamide acid being obtained by the reaction of a diamine component containing a diamine having a structure represented by the following formula [1] and a tetracarboxylic dianhydride component. (In formula [1], A1 and A2 are each independently a monocyclic group or a fused ring group optionally having a substituent, and A1 and A2 are not simultaneously a monocyclic group. X1 and X2 are each independently a single bond, an oxygen atom, or a sulfur atom. Q is an alkylene group having a carbon number of 1 or 2. m and n are each independently an integer of 1 to 3.)

Description

TECHNICAL FIELD

[0001] The present application relates to a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element using the same. BACKGROUND

[0002] Now, in most cases, a liquid crystal alignment film used in a liquid crystal display element uses a polyimide film. The liquid crystal alignment film of the polyimide film is produced by a method of coating a solution of a polyamic acid which is a precursor of a polyimide or a solution of a solvent-soluble polyimide on a substrate, performing baking to obtain a film, and performing orientation treatment such as rubbing treatment on the film. The polyamic acid, the solvent-soluble polyimide is usually produced by polycondensation of a tetracarboxylic acid derivative such as a tetracarboxylic dianhydride and a diamine compound.

[0003] A diamine compound which is a raw material of the above-mentioned polyamic acid, polyimide, etc. has an influence on the characteristics of a liquid crystal alignment film obtained therefrom, and further on the characteristics of a liquid crystal display element, and thus is important. Various diamine compounds have been used and proposed in the past.

[0004] For example, Patent Literature 1 proposes a liquid crystal alignment agent obtained from the following diamine compound.

[0005]

[0006] PRIOR ART DOCUMENTS

[0007] PATENT LITERATURE

[0008] Patent Literature 1: Japanese Patent Application Laid-Open No. 2005-157346 SUMMARY

[0009] Problems to be solved by the invention

[0010] However, in recent years, the liquid crystal display element has progressed in high performance, large area, power saving of display devices, etc., and in addition thereto, the liquid crystal display element is used in various environments, and the characteristics required for the liquid crystal alignment film have become more and more strict. In particular, with the progress of the use of the liquid crystal display element, the problem of difficulty in securing good liquid crystal alignment properties, and the problem of small margin of sensitivity in the production of the liquid crystal alignment film have become remarkable. Note that, here, the margin of sensitivity refers to a range of sensitivity in which good liquid crystal alignment properties can be obtained when polarized ultraviolet rays are irradiated.

[0011] If good liquid crystal alignment properties cannot be ensured, light leakage and poor alignment are likely to occur. In addition, if the sensitivity margin is small, in-plane deviation of the liquid crystal alignment azimuth due to display unevenness over time, or unevenness in the illuminance of an ultraviolet irradiation machine, causes light leakage and unevenness when black is displayed. Thus, while good liquid crystal alignment properties and improved sensitivity margin are strongly required, the above requirements cannot be sufficiently satisfied when the techniques proposed in the past are used.

[0012] The present application was made in view of the above, and aims to provide a liquid crystal alignment agent that can provide a liquid crystal alignment film having good liquid crystal alignment properties and that can increase the sensitivity margin.

[0013] Solution to the problem

[0014] The present inventors and others conducted intensive research in order to solve the above problems, and as a result, found that a liquid crystal alignment agent containing a polymer obtained from a novel diamine satisfies the above problems.

[0015] The present application is based on the above finding, and the gist is as follows.

[0016] A liquid crystal alignment agent characterized by containing at least one polymer selected from the group consisting of a polyamide acid and a polyimide obtained by imidizing the polyamide acid, the polyamide acid being obtained by the reaction of a diamine component containing a diamine having the structure shown in the following formula [1] and a tetracarboxylic dianhydride component.

[0017]

[0018] (In formula [1], A1and A2are each independently a monocyclic group or a fused ring group optionally having a substituent, and A1and A2are not simultaneously a monocyclic group. X1and X2are each independently a single bond, an oxygen atom, or a sulfur atom. Q is an alkylene group having 1 or 2 carbon atoms. m and n are each independently an integer of 1 to 3.)

[0019] Effects of the invention

[0020] The liquid crystal alignment agent according to the present application can provide a liquid crystal alignment film having good liquid crystal alignment properties, and can increase the sensitivity margin. DETAILED DESCRIPTION

[0021] <Specific diamine of the present application>

[0022] The diamine used as a raw material of the liquid crystal alignment agent of the present application is a diamine having the structure shown in the following formula [1].

[0023]

[0024] In the above formula [1], A1and A2are each independently a monocyclic group or a fused ring group optionally having a substituent, and A1and A2are not simultaneously a monocyclic group. X1and X2are each independently a single bond, an oxygen atom, or a sulfur atom. Q is an alkylene group having a carbon number of 1 or 2. m and n are each independently an integer of 1 to 3.

[0025] The monocyclic group refers to a group of atoms remaining by removing two hydrogen atoms from a monocyclic ring. As the monocyclic ring, there can be mentioned, for example, benzene; a 5-membered heterocyclic ring such as furan, thiophene, pyrrole, oxazole, thiazole, imidazole, and pyrazole; and a 6-membered heterocyclic ring such as pyran, pyranone, pyridine, pyridazine, pyrimidine, and pyrazine. The monocyclic ring is preferably benzene or pyridine. Note that in the case where the monocyclic ring is benzene, the monocyclic group is a phenylene group.

[0026] The fused ring group refers to a group of atoms remaining by removing two hydrogen atoms from a fused ring. As the fused ring, there can be mentioned, for example, a fused polycyclic aromatic hydrocarbon such as naphthalene, tetrahydronaphthalene, indene, fluorene, anthracene, phenanthrene, and pyrene; and a fused polycyclic heterocyclic ring such as benzofuran, thionaphthene, indole, carbazole, coumarin, benzoxazinone, quinoline, isoquinoline, acridine, phthalazine, quinazoline, and quinoxaline. The fused ring is preferably naphthalene, anthracene, pyrene, indole, carbazole, coumarin, benzoxazinone, quinoline, or isoquinoline.

[0027] The monocyclic group and the fused ring group can further have a substituent. As the substituent optionally present in the monocyclic group and the fused ring group, there can be mentioned an alkyl group having a carbon number of 1 to 4, an alkoxy group having a carbon number of 1 to 4, and a halogen atom.

[0028] X1and X2are preferably an oxygen atom. From the viewpoint of liquid crystal alignment restraining force, Q is preferably an alkylene group having a carbon number of 2. m and n are preferably 1.

[0029] As preferable specific examples of the specific diamine, there can be mentioned the following diamines, but they are not limited thereto.

[0030]

[0031] < Tetra-Carboxylic Dianhydride Component >

[0032] In order to obtain the polyimide precursor of the present application, it is preferable to use a tetra-carboxylic dianhydride represented by the following formula [7] (also referred to as a specific tetra-carboxylic dianhydride) or a derivative thereof as a part of the tetra-carboxylic dianhydride component.

[0033]

[0034] In formula [7], Z1is a tetravalent organic group, and there can be mentioned, for example, the structures of the following formulas (X1-1) to (X1-19).

[0035]

[0036] In the above formulas (X1-1) and (X1-2), R3to R6are each independently a hydrogen atom or an alkyl group having a carbon number of 1 to 4.12 each independently is a hydrogen atom, a halogen atom, an alkyl group having a carbon number of 1 to 6, an alkenyl group having a carbon number of 2 to 6, an alkynyl group having a carbon number of 2 to 6, a monovalent organic group having a carbon number of 1 to 6 containing a fluorine atom, or a phenyl group. Among them, at least one of R3to R6is a group other than a hydrogen atom.

[0037] From the viewpoint of liquid crystal alignment, the structure of X1is preferably the above-described formula (X1-1), (X1-3), (X1-4), among them, more preferably at least one selected from the structures represented by the following formulas (X1-1-1) to (X1-1-5), particularly preferably the following formula (X1-1-1). The tetracarboxylic dianhydride represented by formula [7] or a derivative thereof can be used by mixing two or more.

[0038]

[0039] The use ratio of the tetracarboxylic dianhydride represented by the above-described formula [7] or a derivative thereof is preferably 50 mol% or more, more preferably 70 mol% or more, further preferably 80 mol% or more, with respect to 1 mol of the tetracarboxylic dianhydride component used in the polymer of the present application.

[0040] In addition, the tetracarboxylic dianhydride component used in the polymerization of the polymer of the present application preferably contains the tetracarboxylic dianhydride represented by the above-described formula [7] or a derivative thereof from the viewpoint of the suppression of bright spots caused by decomposition products and the liquid crystal alignment.

[0041] The tetracarboxylic dianhydride component used in the polymerization of the polymer of the present application can also contain a tetracarboxylic dianhydride other than the above-described formula [7] or a derivative thereof.

[0042] The tetracarboxylic dianhydride other than the above-described formula [7] or a derivative thereof can be used in one or two or more kinds in consideration of the liquid crystal alignment, voltage holding properties, and properties such as accumulated charge of the liquid crystal alignment film formed.

[0043] <Polymers of the Invention>

[0044] The polymer in the present application refers to a polyamide acid, and / or a polyimide obtained by imidizing the polyamide acid.

[0045] <Polymide Acid>

[0046] The polyamide acid of the present application is obtained by the reaction of a diamine component containing a specific diamine and a tetracarboxylic dianhydride component.

[0047] There is no limitation on the content ratio of the specific diamine in the diamine component used to obtain the polyamic acid by the reaction with the above-mentioned tetracarboxylic dianhydride component. The content of the specific diamine in the diamine component can be 100%. However, from the viewpoint of satisfying various properties required for the liquid crystal alignment film, such as the property of increasing the pretilt angle of the liquid crystal, the property of improving the vertical alignment property of the liquid crystal, and the like, various diamines can be used in combination. The content ratio of the specific diamine in the diamine component used in the polymerization is preferably 1 to 50 mol%, and particularly preferably 5 to 30 mol%.

[0048] As the diamine other than the specific diamine (hereinafter also referred to as the other diamine) used in combination in the case where the content of the specific diamine is less than 100 mol% in the above-mentioned diamine component, there can be mentioned alicyclic diamines, aromatic-aliphatic diamines, aromatic diamines, heterocyclic diamines, aliphatic diamines, and the like.

[0049] As examples of the alicyclic diamines, there can be mentioned 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 4,4'-diaminodicyclohexylmethane, 4,4'-diamino-3,3'-dimethyldicyclohexylamine, isophorone diamine, and the like.

[0050] Examples of aromatic diamines include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,4-diaminotoluene, 2,5-diaminotoluene, 3,5-diaminotoluene, 1,4-diamino-2-methoxybenzene, 2,5-diamino-p-xylene, 1,3-diamino-4-chlorobenzene, 3,5-diaminobenzoic acid, 1,4-diamino-2,5-dichlorobenzene, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-2,2'-dimethylbibenzyl, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 2,2'-diaminostilbene, 4,4'-diamino-2,2' ...phenylethane, 4,4' -Diaminostilbene, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminobenzophenone, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 3,5-bis(4-aminophenoxy)benzoic acid, 4,4'-bis(4-aminophenoxy)bibenzyl, 2,2-bis[(4-aminophenoxy)methyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, bis[4-(3-aminophenoxy)phenyl]propane 1,1-bis(4-aminophenyl)cyclohexane, α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene, 9,9-bis(4-aminophenyl)fluorene, 2,2-bis(3-aminophenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-diaminodiphenylamine, 2,4-diaminodiphenylamine, 1,8-diaminonaphthalene, 1,5-diaminonaphthalene, 1,5-diaminoanthraquinone, 1,3-diaminopyrene, 1,6-diaminopyrene, 1,8-diaminopyrene, 2,7-diaminofluorene, 1,3-bis(4-aminophenyl)tetramethyldisiloxane, benzidine, 2,2'-dimethylbenzidine, 1, ,2-bis(4-aminophenyl)ethane, 1,3-bis(4-aminophenyl)propane, 1,4-bis(4-aminophenyl)butane, 1,5-bis(4-aminophenyl)pentane, 1,6-bis(4-aminophenyl)hexane, 1,7-bis(4-aminophenyl)heptane, 1,8-bis(4-aminophenyl)octane, 1,9-bis(4-aminophenyl)nonane, 1,10-bis(4-aminophenyl)decane, 1,3-bis(4-aminophenoxy)propane, 1,4-bis(4-aminophenoxy)butane, 1,5-bis(4-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, 1,7-bis(4-aminophenyl)heptane, 1,8-bis(4-aminophenyl)octane, 1,9-bis(4-aminophenyl)nonane,9-bis(4-aminophenoxy)nonane, 1,10-bis(4-aminophenoxy)decane, bis(4- aminophenyl)propane-1,3-dicarboxylate, bis(4-aminophenyl)butane-1,4-dicarboxylate, bis(4-aminophenyl)pentane-1,5-dicarboxylate, bis(4-aminophenyl)hexane-1,6- dicarboxylate, bis(4-aminophenyl)heptane-1,7-dicarboxylate, bis(4- aminophenyl)octane-1,8-dicarboxylate, bis(4-aminophenyl)nonane-1,9- dicarboxylate, bis(4-aminophenyl)decane-1,10-dicarboxylate, 1,3- bis[4-(4-aminophenoxy)phenoxy]propane, 1,4-bis[4-(4- aminophenoxy)phenoxy]butane, 1,5-bis[4-(4-aminophenoxy)phenoxy]pentane, 1,6-bis[4-(4-aminophenoxy)phenoxy]hexane, 1,7-bis[4-(4- aminophenoxy)phenoxy]heptane, 1,8-bis[4-(4-aminophenoxy)phenoxy]octane, 1,9-bis[4-(4-aminophenoxy)phenoxy]nonane, 1,10-bis[4-(4- aminophenoxy)phenoxy]decane, and the like.

[0051] As examples of the aromatic-aliphatic diamine, 3-aminobenzylamine, 4- aminobenzylamine, 3-amino-N-methylbenzylamine, 4-amino-N- methylbenzylamine, 3-aminophenethylamine, 4-aminophenethylamine, 3- amino-N-methylphenethylamine, 4-amino-N-methylphenethylamine, 3-(3- aminopropyl)aniline, 4-(3-aminopropyl)aniline, 3-(3-methylaminopropyl)aniline, 4-(3-methylaminopropyl)aniline, 3-(4-aminobutyl)aniline, 4-(4- aminobutyl)aniline, 3-(4-methylaminobutyl)aniline, 4-(4- methylaminobutyl)aniline, 3-(5-aminopentyl)aniline, 4-(5- aminopentyl)aniline, 3-(5-methylaminopentyl)aniline, 4-(5- methylaminopentyl)aniline, 2-(6-aminonaphthyl)methylamine, 3-(6- aminonaphthyl)methylamine, 2-(6-aminonaphthyl)ethylamine, 3-(6- aminonaphthyl)ethylamine, and the like can be given.

[0052] As examples of the heterocyclic diamine, 2,6-diaminopyridine, 2,4- diaminopyridine, 2,4-diamino-1,3,5-triazine, 2,7-diaminodibenzofuran, 3,6- diaminocarbazole, 2,4-diamino-6-isopropyl-1,3,5-triazine, 2,5-bis(4- aminophenyl)-1,3,4-oxadiazole, and the like can be given.

[0053] As examples of the aliphatic diamine, 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,3-diamino-2,2-dimethylpropane, 1,6-diamino-2,5-dimethylhexane, 1,7-diamino-2,5-dimethylheptane, 1,7-diamino-4,4-dimethylheptane, 1,7-diamino-3-methylheptane, 1,9-diamino-5-methylnonane, 1,12-diaminododecane, 1,18-diamino-octadecane, 1,2-bis(3-aminopropoxy)ethane, and the like can be given.

[0054] A diamine having a side chain having an alkyl group, a fluorine-containing alkyl group, an aromatic ring, an aliphatic ring, a heterocyclic ring, or a macrocyclic substituent including them can also be used in combination. Specifically, diamines represented by the following formulae [DA-101] to [DA-130] can be given as examples.

[0055]

[0056] (R6is an alkyl group or a fluorine-containing alkyl group having a carbon number of 1 to 22.)

[0057]

[0058] (S5is -COO-, -OCO-, -CONH-, -NHCO-, -CH2-, -O-, -CO-, or NH-, R6is an alkyl group or a fluorine-containing alkyl group having a carbon number of 1 to 22.)

[0059]

[0060] (S6is -O-, -OCH2-, -CH2O-, -COOCH2-, or CH2OCO-, R7is an alkyl group, an alkoxy group, a fluorine-containing alkyl group, or a fluorine-containing alkoxy group having a carbon number of 1 to 22.)

[0061]

[0062] (S7is -COO-, -OCO-, -CONH-, -NHCO-, -COOCH2-, -CH2OCO-, -CH2O-, -OCH2-, or CH2-, R8is an alkyl group, an alkoxy group, a fluorine-containing alkyl group, or a fluorine-containing alkoxy group having a carbon number of 1 to 22.)

[0063]

[0064] (S8 is -COO-, -OCO-, -CONH-, -NHCO-, -COOCH2-, -CH2OCO-, -CH2O-, -OCH2-, -CH2-, -O-, or NH-, and R9 is a fluorine group, a cyano group, a trifluoromethane group, a nitro group, an azo group, a formyl group, an acetyl group, an acetoxy group, or a hydroxyl group.)

[0065]

[0066] (R 10 is an alkyl group having 3 to 12 carbon atoms, and the cis-trans isomers of 1,4-cyclohexylene are the trans isomer.

[0067]

[0068] In the case of orientation treatment by light, further stable pretilt angles can be obtained by using specific diamines in combination with the diamines of the above [DA-101] to [DA-130], and thus are preferred. As more preferred diamines that can be used in combination, diamines of the formulae [DA-110] to [DA-130], more preferably [DA-110] to [DA-116] are preferred. The preferred content of these diamines is not particularly limited, and is preferably 5 to 50 mol% in the diamine component, and from the viewpoint of printability, 5 to 30 mol% is preferred.

[0069] In addition, diamines represented by the formulae [DA-131] to [DA-138] below can also be used in combination.

[0070]

[0071] (m is an integer of 0 to 3, and n in the formula [DA-138] is an integer of 1 to 5).

[0072] By containing diamines of the formula [DA-131], the formula [DA-132], and the like, the voltage holding properties at the time of forming a liquid crystal alignment film can be improved, and the diamines of the formulae [DA-133] to [DA-138] can effectively reduce accumulated charges.

[0073] Further, diamino siloxanes represented by the formula [DA-139] below and the like can also be cited as other diamines.

[0074]

[0075] (m is an integer of 1 to 10).

[0076] Further, diamines represented by the following formula (8) can also be cited as other diamines.

[0077] H2N-Y2-NH2 (8)

[0078] (In formula (8), Y2is a 2-valent organic group having a nitrogen atom bonded to an aromatic group or a nitrogen-containing aromatic heterocycle.)

[0079] As examples of Y2in formula (8), the following formulae (Y2-1) to (Y2-12) can be listed.

[0080]

[0081] Other diamines can also be used in one kind, or two or more kinds in mixture, depending on the liquid crystal alignment properties, voltage holding properties, accumulated charge, and other properties when forming a liquid crystal alignment film.

[0082] <Manufacture of polyamic acid>

[0083] The method of obtaining the polyamic acid of the present application by the reaction of the tetracarboxylic dianhydride component and the diamine component can use a known method. For example, there is a method of reacting the tetracarboxylic dianhydride component and the diamine component in an organic solvent. At this time, the reaction of the tetracarboxylic dianhydride component and the diamine is advantageous from the viewpoint that it proceeds relatively easily in an organic solvent, and no by-products are produced.

[0084] As the organic solvent used in the reaction of the tetracarboxylic dianhydride component and the diamine, there is no limitation if the produced polyamic acid dissolves. Specific examples thereof are listed below.

[0085] N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-methylcaprolactam, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, γ-butyrolactone, isopropyl alcohol, methoxymethylamyl alcohol, dipentene, ethylamyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methyl cyclohexene, propyl ether, dihexyl ether, dioxane, n-hexane, n-pentane, n-octane, diethyl ether, cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, diethylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, 3-methoxy-N,N-dimethylpropanamide, 3-ethoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, and the like. They can be used alone or in combination. Furthermore, even solvents that do not dissolve polyamic acid can be used in combination with the above solvents within a range in which the generated polyamic acid does not precipitate.

[0086] In addition, moisture in the organic solvent inhibits the polymerization reaction and further becomes a cause of hydrolysis of the generated polyamic acid, and thus it is preferable that the organic solvent be dried as much as possible.

[0087] When the tetracarboxylic dianhydride component and the diamine component are reacted in an organic solvent, any of the following methods can be used: a method in which a solution in which the diamine component is dispersed or dissolved in an organic solvent is stirred; a method in which the tetracarboxylic dianhydride component is added directly or dispersed or dissolved in an organic solvent; a method in which the diamine component is added to a solution in which the tetracarboxylic dianhydride component is dispersed or dissolved in an organic solvent; and a method in which the tetracarboxylic dianhydride component and the diamine component are alternately added. In addition, when the tetracarboxylic dianhydride component or the diamine component contains a plurality of compounds, the reaction can be performed in a state in which they are previously mixed, or the reactions can be performed sequentially, or low-molecular-weight bodies obtained by the respective reactions can be mixed to obtain a high-molecular-weight body.

[0088] The temperature at which the tetracarboxylic dianhydride component and the diamine component are reacted can be any temperature in the range of -20 to 150°C, and is preferably in the range of -5 to 100°C. In addition, the reaction can be performed at any concentration, but if the concentration is too low, it is difficult to obtain a polymer having a high molecular weight, and if the concentration is too high, the viscosity of the reaction solution is too high, and it is difficult to perform uniform stirring, and therefore the total concentration of the tetracarboxylic dianhydride component and the diamine component in the reaction solution is preferably 1 to 50% by mass, and more preferably 5 to 30% by mass. The reaction can be performed at a high concentration at the initial stage, and then an organic solvent can be added.

[0089] In the polymerization reaction of the polyamic acid, the ratio of the total number of moles of the tetracarboxylic dianhydride component to the total number of moles of the diamine component is preferably 0.8 to 1.2, and more preferably 0.9 to 1.1. As in the case of a general polycondensation reaction, the closer the molar ratio is to 1.0, the greater the molecular weight of the polyamic acid produced.

[0090] < Polyimide >

[0091] The polyimide of the present application is a polyimide obtained by dehydrating and ring-closing the aforementioned polyamic acid, and is useful as a polymer for obtaining a liquid crystal alignment film.

[0092] In the polyimide of the present application, the dehydration and ring-closing rate (imidization rate) of the amic acid group does not necessarily need to be 100%, and can be arbitrarily adjusted depending on the use and purpose.

[0093] As a method of imidizing the polyamic acid, a thermal imidization method in which a solution of the polyamic acid is directly heated, and a catalytic imidization method in which a catalyst is added to a solution of the polyamic acid can be cited.

[0094] The temperature at which the polyamic acid is subjected to thermal imidization in a solution is 100 to 400°C, and is preferably 120 to 250°C, and it is preferable to perform this while removing water produced by the imidization reaction to the outside of the system.

[0095] The catalytic imidization of the polyamic acid can be performed by adding a basic catalyst and an acid anhydride to a solution of the polyamic acid, and stirring at -20 to 250°C, preferably 0 to 180°C. The amount of the basic catalyst is 0.5 to 30 moles, preferably 2 to 20 moles, per mole of the amic acid group, and the amount of the acid anhydride is 1 to 50 moles, preferably 3 to 30 moles, per mole of the amic acid group. As the basic catalyst, pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, and the like can be exemplified, among which pyridine is preferred because of its suitable basicity for the reaction. As the acid anhydride, acetic anhydride, trimellitic anhydride, pyromellitic anhydride, and the like can be exemplified, among which acetic anhydride is preferred because purification after the reaction becomes easy. The imidization rate achieved by the catalytic imidization can be controlled by adjusting the amount of the catalyst, the reaction temperature, the reaction time, and the like.

[0096] The molecular weight of the polymer contained in the liquid crystal alignment agent of the present application is preferably 5,000 to 1,000,000, more preferably 10,000 to 150,000, in terms of the weight average molecular weight determined by the gel permeation chromatography (GPC) method, in consideration of the strength of the obtained coating film, the workability at the time of coating film formation, and the uniformity of the coating film.

[0097] < Liquid crystal alignment agent >

[0098] The liquid crystal alignment agent of the present application is a coating liquid for forming a liquid crystal alignment film, and is a solution in which a resin component for forming a resin coating film is dissolved in an organic solvent. Here, the aforementioned resin component contains at least one polymer selected from the polymers of the present application described above. The content of the resin component in the liquid crystal alignment agent is preferably 1 to 20 mass%, more preferably 3 to 15 mass%, particularly preferably 3 to 10 mass%.

[0099] The resin component can be the polymer of the present application alone, or can be mixed with other polymers in addition thereto. In this case, the content of the aforementioned other polymers in the resin component is 0.5 to 15 mass%, preferably 1 to 10 mass%.

[0100] The other polymers can be exemplified by, for example, a polyamic acid or a polyimide obtained by using a diamine compound other than the specific diamine compound as a diamine component that reacts with a tetracarboxylic dianhydride component.

[0101] The organic solvent used in the liquid crystal alignment agent of the present application is not particularly limited as long as it is an organic solvent that dissolves the resin component. Specific examples thereof are listed below.

[0102] As the solvent (poor solvent) for improving the uniformity of film thickness and surface smoothness, the following solvents can be exemplified.

[0103] The liquid crystal alignment agent of the present application can contain components other than the above. As examples thereof, there are solvent materials and the like for improving the uniformity of film thickness and surface smoothness when the liquid crystal alignment agent is applied, compounds and the like for improving the adhesion of the liquid crystal alignment film to a substrate.

[0104] As specific examples of the solvent (poor solvent) for improving the uniformity of film thickness and surface smoothness, the following solvents can be exemplified.

[0105] As the solvent having a low surface tension, for example, isopropyl alcohol, methoxypentanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butyl carbitol, ethyl carbitol, ethyl carbitol acetate, ethylene glycol, ethylene glycol monoacetate, ethylene glycol mono isopropyl ether, ethylene glycol mono butyl ether, propylene glycol, propylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoacetate, diethylene glycol dimethyl ether, dipropylene glycol monoacetate monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoacetate monopropyl ether, dipropylene glycol dimethyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycol methyl ether, 3-methyl-3-methoxybutanol, diisopropyl ether, ethyl isobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butyl ether, diisobutyl ketone, methyl cyclohexene, propyl ether, dihexyl ether, 1-hexanol, n-hexane, n-pentane, n-octane, diethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 2-butoxy-1-propanol, 2,6-dimethyl-4-heptanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2-(2-ethoxypropoxy)propanol, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, and the like can be exemplified.

[0106] These poor solvents can be used singly or in a mixture of two or more. In the case of using the above-mentioned solvents, it is preferred that 5 to 80% by mass, more preferably 20 to 60% by mass, of the total solvents contained in the liquid crystal alignment agent.

[0107] As the compound for improving the uniformity of film thickness and surface smoothness, a fluorine-based surfactant, a silicone-based surfactant, a nonionic surfactant, and the like can be exemplified.

[0108] More specifically, for example, F-top EF301, EF303, EF352 (manufactured by TOHKEM PRODUCT S Corporation), Megaface F171, F173, R-30 (manufactured by DIC Corporation), Fluorad FC430, FC431 (manufactured by Sumitomo 3M Limited), AsahiGuard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.), etc. The usage ratio of these surfactants is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, relative to 100 parts by mass of the resin component contained in the liquid crystal aligning agent.

[0109] As a specific example of the compound which improves the adhesiveness of a liquid crystal aligning film and a substrate, the compound containing a functional silane shown below, the compound containing an epoxy group, etc. are mentioned.

[0110] For example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2- aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3- aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N- ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3- aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N- trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10- triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9- triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N- benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N- phenyl-3-aminopropyltriethoxysilane, N-bis(oxaethylidene)-3- aminopropyltrimethoxysilane, N-bis(oxaethylidene)-3-aminopropyltriethoxysilane, 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, glycerol diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, and the like can be cited.

[0111] Further, in addition to improving the adhesion of the substrate and the film, in order to prevent a decrease in electrical characteristics due to the backlight, etc., it is preferable to contain a phenolic plastic-based additive such as the following. Specific phenolic plastic-based additives are shown below.

[0112]

[0113] In the case of using a compound that improves adhesion to the substrate, the amount used is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, with respect to 100 parts by mass of the resin component. If the amount used is less than 0.1 parts by mass, the effect of improving adhesion cannot be expected, and if it is more than 30 parts by mass, the alignment properties of the liquid crystal can deteriorate.

[0114] In addition to the above, the liquid crystal aligning agent of the present invention may contain a dielectric, a conductive substance, or a crosslinking compound for improving the hardness and density of the liquid crystal aligning film in order to change the electrical properties such as the dielectric constant and conductivity of the liquid crystal aligning film.

[0115] <Liquid crystal alignment film and liquid crystal display element>

[0116] The liquid crystal alignment agent of the present invention can be applied to a substrate and fired, and then oriented by rubbing, light irradiation, etc., or not oriented in vertical alignment applications, thereby used as a liquid crystal alignment film. At this time, as the substrate used, if it is a substrate with high transparency, it is not particularly limited, and plastic substrates such as glass substrates, acrylic substrates, polycarbonate substrates, etc. can be used. In addition, from the viewpoint of process simplification, it is preferred to use a substrate formed with an ITO electrode for driving liquid crystals, etc. In addition, in a reflective liquid crystal display element, if only a single-sided substrate is used, then an opaque object such as a silicon wafer can be used, and the electrode at this time can also use a material that reflects light such as aluminum.

[0117] The method for applying the liquid crystal aligning agent is not particularly limited, and is generally performed industrially by screen printing, offset printing, flexographic printing, inkjet printing, etc. Other coating methods include dipping, roll coating, slit coating, spin coating, etc., which can be used as needed.

[0118] After the liquid crystal alignment agent is applied to the substrate, the calcination can be performed by heating means such as a hot plate at 50 to 300°C, preferably 80 to 250°C, to evaporate the solvent and form a coating film. The thickness of the coating film formed after calcination is preferably 5 to 300 nm, more preferably 10 to 100 nm, because if it is too thick, it will be disadvantageous in terms of power consumption of the liquid crystal display element, while if it is too thin, the reliability of the liquid crystal display element may be reduced. When the liquid crystal is horizontally aligned or tilted, the calcined coating film is treated by friction or irradiation with polarized ultraviolet light.

[0119] The method for performing an orientation treatment on the liquid crystal alignment film obtained by the liquid crystal alignment agent of the present invention may be a rubbing treatment method. However, when using the liquid crystal alignment agent of the present invention, since the orientation treatment can be performed with an expanded irradiation margin as described above, a photo-alignment treatment method is preferred. As a preferred example of the photo-alignment treatment method, radiation having a wavelength of 100 to 800 nm, preferably ultraviolet light or visible light, can be used on the surface of the liquid crystal alignment film. Among them, ultraviolet light having a wavelength of 100 to 400 nm is preferred, and more preferably 200 to 400 nm.

[0120] The light irradiation dose in the photo-alignment treatment method is preferably 1 to 10,000 mJ / cm 2, wherein more preferably 100 to 5000 mJ / cm 2 , particularly preferably 100 to 2000 mJ / cm 2 .

[0121] The liquid crystal display element of the present application is formed by preparing a substrate having a liquid crystal alignment film using the liquid crystal alignment agent of the present application by the above-mentioned method, and then forming a liquid crystal cell using a known method.

[0122] If an example of the liquid crystal cell preparation is cited, a method of preparing one pair of substrates having a liquid crystal alignment film formed thereon, adhering the other substrate to the liquid crystal alignment film surface of one substrate in a manner that the inside is formed by the liquid crystal alignment film surface, injecting liquid crystal under reduced pressure, and sealing, or a method of adhering a substrate to the liquid crystal alignment film surface on which spacers are dispersed, and sealing after dropping liquid crystal, and the like can be exemplified. The thickness of the spacers is preferably 1 to 30 μm, more preferably 2 to 10 μm.

[0123] Example

[0124] The following examples are given to more specifically illustrate the present application, but the present application is not limited by them. The abbreviations of the following compounds and the measuring methods of each property are described below.

[0125] NMP: N-methyl-2-pyrrolidone, GBL: γ-butyrolactone,

[0126] BCS: butyl cellosolve,

[0127]

[0128]

[0129] 1. Synthesis example of compound [DA-3]

[0130] The compound [DA-3] was synthesized according to the following scheme.

[0131]

[0132] Synthesis of compound [1]

[0133] To dimethylformamide (1050 g) was added 6-bromonaphthalen-2-ol (150 g, 672 mmol) under ice cooling. To this was added sodium hydride (60%, 29.6 g) little by little under ice cooling, and after stirring for 1 hour under ice cooling, benzyl bromide (121 g) was added, and stirred for 1 hour at room temperature. Further, pure water (750 g) was added little by little under ice cooling and stirred to precipitate crystals. The obtained liquid containing crystals was filtered, and to the filtrate was performed slurry washing with methanol (750 g), and the filtrate was filtered and dried, whereby Compound [1] (yield: 207 g, yield: 98%, white crystals) was obtained.

[0134] 1H-NMR (400 MHz, DMSO-d6, δ ppm): 8.13 (d, 1H, J = 2.0 Hz), 7.85 (d, 1H, J = 9.2 Hz), 7.78 (d, 1H, J = 8.8 Hz), 7.58 (dd, 1H, J = 8.8 Hz, 2.4 Hz), 7.53-7.48 (m, 3H), 7.44-7.40 (m, 2H), 7.38-7.33 (m, 1H), 7.30 (dd, 1H, J = 9.0 Hz, 2.6 Hz), 5.22 (s, 2H).

[0135] Synthesis of Compound [2]

[0136] To tetrahydrofuran (1000 g) was added sodium tert-butoxide (82.6 g) and benzophenone imine (126 g), and stirred for 30 minutes at room temperature. To this was added Compound [1] (207 g, 661 mmol), Pd2(dba)3(3.03 g) and BINAP (6.17 g), and stirred for 23 hours at 65°C under nitrogen atmosphere. After cooling to room temperature, 1 N hydrochloric acid (1000 g) was added, and stirred for 15 minutes at room temperature, and the aqueous layer was separated. Further, to the organic layer was added ethyl acetate (200 g), hexane (100 g) and 1 N hydrochloric acid (500 g), and added to the separated aqueous layer. Under water cooling, sodium hydroxide (80 g) was added to make alkaline. The organic layer was separated, washed with saturated sodium chloride aqueous solution, dried with sodium sulfate, filtered, and the filtrate was concentrated, whereby a crude product (154 g) was obtained. To the crude product was added ethyl acetate (462 g) to dissolve by heating at 70°C, and hexane (770 g) was added, and cooled. Then, it was filtered, and the filtrate was dried, whereby Compound [2] (yield: 124 g, yield: 74%, light brown crystals) was obtained.

[0137] 1H-NMR (400 MHz, DMSO-d6, δ ppm): 7.50-7.43 (m, 4H), 7.42-7.37 (m, 2H), 7.35-7.30 (m, 1H), 7.19 (d, 1H, J = 2.8 Hz), 7.04 (dd, 1H, J = 8.8 Hz, 2.8 Hz), 6.90 (dd, 1H, J = 8.8 Hz, 2.0 Hz), 6.80 (d, 1H, J = 2.0 Hz), 5.13 (br, 4H).

[0138] Synthesis of compound [3]

[0139] To dichloromethane (1000 g) were added compound [2] (124 g, 497 mmol) and di-tert-butyl dicarbonate (130 g), and stirred at room temperature for 20 hours. Since the reaction was not completed, di-tert-butyl dicarbonate (10 g) was further added, and stirred at room temperature for 20 hours. Saturated aqueous sodium bicarbonate solution (1000 mL) and dichloromethane (300 g) were added, and subjected to liquid separation. The organic layer was washed with pure water (450 mL), saturated aqueous sodium chloride solution (300 mL) in this order, dried over sodium sulfate, and subjected to filtration, and the filtrate was concentrated, whereby a crude product (198 g) was obtained. To the crude product was added ethyl acetate (600 g), and dissolved by heating at 70°C, and then hexane (1000 g) was added, and subjected to cooling. Then, filtration was performed, and the filtrate was dried, whereby compound [3] (yield: 142 g, 82%, white crystal) was obtained.

[0140] 1H-NMR (400 MHz, DMSO-d6, δ ppm): 9.46 (s, 1H), 8.02 (s, 1H), 7.69 (t, 2H, J = 8.6 Hz), 7.52-7.49 (m, 2H), 7.45 (dd, 1H, J = 9.0 Hz, 2.2 Hz), 7.43-7.39 (m, 2H), 7.37-7.32 (m, 2H), 7.17 (dd, 1H, J = 9.0 Hz, 2.6 Hz), 5.18 (s, 2H), 1.50 (s, 9H).

[0141] Synthesis of compound [4]

[0142] To ethanol (976 g) were added compound [3] (122 g, 349 mmol) and 5% palladium-carbon (12.2 g), and stirred at 40°C for 96 hours under a hydrogen gas atmosphere. The catalyst was filtered from the obtained stirred solution, and the filtrate was concentrated, whereby compound [4] (yield: 89.3 g, 99%, white crystal) was obtained.

[0143] 1H-NMR (400 MHz, DMSO-d6, δ ppm): 9.52 (s, 1H), 9.37 (s, 1H), 7.94 (s, 1H), 7.62-7.59 (m, 1H), 7.56 (d, 1H, J = 9.2 Hz), 7.39 (dd, 1H, J = 9.0 Hz, 2.2 Hz), 7.04-7.00 (m, 2H), 1.50 (s, 9H).

[0144] Synthesis of compound [5]

[0145] To dimethyl sulfoxide (500 g) were added 4-chloronitrobenzene (100 g, 635 mmol), ethylene glycol (551 g), and sodium hydroxide (23.1 g), and stirred at 100°C for 19 hours. After cooling to room temperature, ethyl acetate (560 g) and pure water (700 g) were added, and partitioned. The upper layer was recovered, and to the lower layer was added ethyl acetate (300 g) and partitioned, and the upper layers were combined. To the combined upper layer was added pure water (400 g) and saturated sodium chloride aqueous solution (200 g) and partitioned again, and the ethyl acetate layer was dried with sodium sulfate, filtered, and concentrated, thereby obtaining a crude product (110 g). To the crude product was added ethyl acetate (330 g) and dissolved by heating at 60°C, and then hexane (550 g) was added and cooled. The resulting liquid was filtered, and the filtrate was dried, thereby obtaining compound [5] (yield: 64.2 g, 55%, pale yellow crystals).

[0146] 1H-NMR (400 MHz, DMSO-d6, δ ppm): 8.21 (d, 2H, J = 9.4 Hz), 7.16 (d, 2H, J = 9.4 Hz), 4.97 (t, 1H, J = 5.6 Hz), 4.15 (t, 2H, J = 4.8 Hz), 3.77-3.73 (m, 2H).

[0147] Synthesis of compound [6]

[0148] To dichloromethane (1264 g) was added compound [5] (63.2 g, 345 mmol) and cooled under ice cooling. To this was added triethylamine (52.4 g), tosyl chloride (69.0 g), and 4-dimethylaminopyridine (1.26 g), and stirred at room temperature for 19 hours. Pure water (632 g) was added, partitioned, and the dichloromethane layer was recovered, and successively washed with IN hydrochloric acid (300 g), pure water (300 g), saturated sodium chloride aqueous solution (300 g), dried with anhydrous sodium sulfate, filtered, and the filtrate was concentrated, thereby obtaining compound [6] (yield: 108 g, 93%, white crystals).

[0149] 1H-NMR (400 MHz, DMSO-d6, δ ppm): 8.18 (d, 2H, J = 9.2 Hz), 7.80 (d, 2H, J = 8.6 Hz), 7.47 (d, 2H, J = 8.6 Hz), 7.05 (d, 2H, J = 9.2 Hz), 4.40-4.37 (m, 2H), 4.35-4.31 (m, 2H), 2.41 (s, 3H).

[0150] Synthesis of compound [7]

[0151] To dimethylformamide (360 g) were added compound [4] (45.0 g, 174 mmol), compound [6] (61.5 g), and potassium carbonate (36.0 g), and stirred at 80°C for 21 hours. After cooling to room temperature, water (720 g) was added to precipitate crystals. The resulting liquid containing crystals was filtered, and the filtrate was washed with slurry using methanol (360 g), filtered, and dried, thereby obtaining compound [7] (yield: 67.2 g, yield: 91%, light yellowish crystal).

[0152] 1H-NMR (400 MHz, DMSO-d6, δ ppm): 9.47 (s, 1H), 8.23 (d, 2H, J = 9.2 Hz), 8.02 (s, 1H), 7.72-7.69 (m, 2H), 7.46 (dd, 1H, J = 8.8 Hz, 2.0 Hz), 7.31 (d, 1H, J = 2.4 Hz), 7.24 (d, 2H, J = 9.2 Hz), 7.14 (dd, 1H, J = 9.0 Hz, 2.6 Hz), 4.56-4.53 (m, 2H), 4.46-4.43 (m, 2H), 1.50 (s, 9H).

[0153] Synthesis of compound [8]

[0154] To chloroform (1096 g) was added compound [7] (73.1 g, 172 mmol), and while stirring under water cooling, trifluoroacetic acid (98.1 g) was added, and stirred at 50°C for 19 hours. After cooling the resulting stirred solution to room temperature, triethylamine (87.0 g) and water (1096 g) were added to precipitate crystals. The resulting liquid containing crystals was filtered, and the filtrate was washed with slurry using methanol (365 g), filtered, and dried, thereby obtaining a crude product (49.5 g). To the crude product was added dimethylformamide (124 g), and after dissolving by heating at 80°C, methanol (248 g) was added to cool, and crystals were precipitated. The resulting liquid containing crystals was filtered, and the filtrate was dried, thereby obtaining compound [8] (yield: 47.3 g, yield: 85%, orange crystal).

[0155] 1H-NMR (400MHz, DMSO-d6, δppm): 8.23 ​​(d, 2H, J = 9.2Hz), 7.51 (dd, 1H, J = 8.8Hz, 2.4Hz), 7.45 (dd, 1H, J = 8.8Hz, 2.4Hz), 7.24 (dd, 2H, J = 9. 2Hz, 2.4Hz), 7.27 (s, 1H), 7.01 (d, 1H, J = 9.2Hz), 6.91 (d, 1H, J = 8.8Hz), 6.80 (s, 1H), 5.15 (br, 2H), 4.55-4.51 (m, 2H), 4.41-4.37 (m, 2H).

[0156] Synthesis of compound [DA-3]

[0157] Compound [8] (46.4 g, 143 mmol) and 5% palladium carbon (4.6 g) were added to dimethylformamide (371 g) and stirred at 60°C for 19 hours under a hydrogen atmosphere. Since the reaction did not proceed much, the mixture was stirred at 60°C for 8 hours under a 0.4 MPa hydrogen atmosphere in an autoclave. After nitrogen substitution, the catalyst was filtered and the filtrate was concentrated to a content of 80 g. Dimethylformamide (46 g) was added and dissolved by heating at 90°C. Methanol (210 g) was added and cooled to precipitate crystals. The resulting liquid containing the crystals was then filtered and the filtrate was dried to obtain compound [DA-3] (yield: 33.4 g, yield: 79%, pale purple crystals).

[0158] 1H-NMR (400MHz, DMSO-d6, δppm): 7.50 (d, 1H, J = 8.8Hz), 7.44 (d, 1H, J = 8.8Hz), 7.13 (d, 1H, J = 2.8Hz), 7.00 (dd, 1H, J = 8.8Hz, 2.8Hz), 6.90 (dd, 1H, J = 8 .8Hz,2.4Hz),6.79(d,1H,J=2.4Hz),6.71(d,2H,J=8.8Hz),6.52(d,2H,J= 8.8Hz),5.13(br,2H),4.63(br,2H),4.28-4.25(m,2H),4.20-4.17(m,2H).

[0159] 2. Synthesis example of compound [DA-4]

[0160] Compound [DA-4] was synthesized according to the following scheme.

[0161]

[0162] Synthesis of compound [4]

[0163] Compound [4] was used as a synthetic intermediate of Compound [3].

[0164] Synthesis of Compound [9]

[0165] To dimethylformamide (607 g) were added ethylene glycol dimethanesulfonate (60.7 g, 164 mmol), Compound [4] (89.3 g), and potassium carbonate (56.7 g), and stirred at 80°C for 22 hours. After the stirred solution was cooled to room temperature, water (1200 g) was added to precipitate crystals. Then, the obtained crystal-containing liquid was filtered, and the filtrate was washed with a slurry using methanol (450 g), filtered, and dried, thereby obtaining a crude product (83.9 g). To the crude product was added dimethylformamide (839 g), and after the solution was dissolved by heating at 90°C, methanol (839 g) was added to cool and precipitate crystals. Then, the obtained crystal-containing liquid was filtered, and the filtrate was dried, thereby obtaining Compound [9] (yield: 71.2 g, 80%, orange crystals).

[0166] 1H-NMR (400 MHz, DMSO-d6, δ ppm): 9.43 (s, 2H), 7.99 (br, 2H), 7.67 (d, 4H, J = 8.8 Hz), 7.43 (dd, 2H, J = 8.8 Hz, 2.4 Hz), 7.28 (d, 2H, J = 2.4 Hz), 7.12 (dd, 2H, J = 8.8 Hz, 2.4 Hz), 4.42 (s, 4H), 1.47 (s, 18H).

[0167] Synthesis of Compound [DA-4]

[0168] To chloroform (1143 g) was added Compound [9] (71.2 g, 129 mmol), and cooled under water cooling. To this was added trifluoroacetic acid (160 g), and stirred at 50°C for 24 hours. After cooling to room temperature, triethylamine (142 g) and water (1143 g) were added to precipitate crystals. Then, the obtained crystal-containing liquid was filtered, and the filtrate was washed with a slurry using methanol (400 g), filtered, and dried, thereby obtaining a crude product (37.5 g). To the crude product was added dimethylformamide (225 g), and after the solution was dissolved by heating at 90°C, methanol (225 g) was added to cool and precipitate crystals. The obtained crystal-containing liquid was filtered, and the filtrate was dried, thereby obtaining Compound [DA-4] (yield: 33.5 g, 75%, light red purple crystals).

[0169] 1H-NMR (400 MHz, DMSO-d6, δ ppm): 7.51 (d, 2H, J = 8.8 Hz), 7.45 (d, 2H, J = 8.8 Hz), 7.17 (d, 2H, J = 2.4 Hz), 7.02 (dd, 2H, J = 8.8 Hz, 2.4 Hz), 6.91 (dd, 2H, J = 8.8 Hz, 2.4 Hz), 6.80 (d, 2H, J = 2.4 Hz), 5.14 (br, 4H), 4.37 (s, 4H).

[0170] 3. Synthesis example of compound [DA-5]

[0171] The compound [DA-5] was synthesized according to the following scheme.

[0172]

[0173] Synthesis of compound [4]

[0174] The compound [4] was used as an intermediate for synthesis of the compound [3].

[0175] Synthesis of compound

[10]

[0176] To 4-hydroxy-4'-nitro-biphenyl (5.00 g, 23.2 mmol) and potassium carbonate (8.02 g) in dimethylformamide (35 g) was stirred at 80°C for 30 minutes. To this was added a solution of 2-bromoethanol (4.35 g) in dimethylformamide (5 g) and stirred at 100°C for 16 hours. After cooling to room temperature, pure water (80 g) was added and stirred, and the precipitate was filtered. The filtrate was washed with slurry using methanol (35 g), filtered, and the filtrate was dried, thereby obtaining the compound

[10] (yield: 4.35 g, yield: 72%, yellow crystal).

[0177] 1H-NMR (400 MHz, DMSO-d6, δ ppm): 8.27 (d, 2H, J = 7.2 Hz), 7.92 (d, 2H, J = 7.2 Hz), 7.76 (d, 2H, J = 6.8 Hz), 7.09 (d, 2H, J = 6.8 Hz), 4.90 (t, 1H, J = 4.2 Hz), 4.07 (t, 2H, J = 4.0 Hz), 3.77-3.73 (m, 2H).

[0178] Synthesis of compound

[11]

[0179] To compound

[10] (4.00 g, 15.4 mmol) in dichloromethane (80 g) was added triethylamine (2.34 g), tosyl chloride (3.09 g) and 4-dimethylaminopyridine (0.06 g) under ice cooling. After stirring at room temperature for 21 hours, water (40 g) was added, and the mixture was subjected to liquid separation. The dichloromethane layer was recovered, and subjected to liquid separation washing with IN hydrochloric acid (40 g), water (40 g) and saturated sodium chloride aqueous solution (20 g) in this order, dried over anhydrous magnesium sulfate, filtered, and concentrated. Thus, compound

[11] (6.10 g, yield: 96%, orange solid) was obtained.

[0180] 1H-NMR (400 MHz, DMSO-d6, δ ppm): 8.27 (d, 2H, J = 7.2 Hz), 7.92 (d, 2H, J = 7.2 Hz), 7.81 (d, 2H, J = 6.8 Hz), 7.74 (d, 2H, J = 7.2 Hz), 7.48 (d, 2H, J = 6.8 Hz), 7.00 (d, 2H, J = 7.2 Hz), 4.39-4.36 (m, 2H), 4.26-4.23 (m, 2H), 2.09 (s, 3H).

[0181] Synthesis of compound

[12]

[0182] To compound [4] (3.64 g, 14.0 mmol), compound

[11] (6.10 g) and potassium carbonate (2.91 g) in dimethylformamide (36 g) was added, and stirred at 80°C for 21 hours. After cooling to room temperature, water (72 g) was added to precipitate crystals. The mixture was filtered, and the filter was washed with methanol (36 g) to obtain compound

[12] (5.80 g, yield: 83%, pale yellow crystals).

[0183] 1H-NMR (400 MHz, DMSO-d6, δ ppm): 9.44 (s, 1H), 8.27 (d, 2H, J = 7.2 Hz), 8.01 (s, 1H), 7.94 (d, 2H, J = 7.2 Hz), 7.80-7.77 (m, 2H), 7.71 (d, 2H, J = 7.2 Hz), 7.47 (dd, 1H, J = 7.2 Hz, 1.6 Hz), 7.31 (d, 1H, J = 1.6 Hz), 7.19-7.15 (m, 3H), 4.46-4.44 (m, 4H), 1.50 (s, 9H).

[0184] Synthesis of compound

[13]

[0185] Compound

[12] (5.80 g, 11.6 mmol) was added to chloroform (87 g) and cooled under water cooling. Trifluoroacetic acid (6.61 g) was added thereto and stirred at 50°C for 22 hours. After cooling to room temperature, triethylamine (5.86 g) and pure water (87 g) were added to precipitate crystals. The obtained liquid containing crystals was filtered, and the filtrate was slurry-washed with methanol (60 g), filtered, and the filtrate was dried to obtain a crude product (4.3 g). Dimethylformamide (43 g) was added to the crude product, and after heating and stirring at 80°C, methanol (43 g) was added and cooled, filtered, and the filtrate was dried to obtain compound

[13] (yield: 4.13 g, yield: 89%, orange crystals).

[0186] 1H-NMR (400MHz, DMSO-d6, δppm): 8.27 (d, 2H, J = 6.8Hz), 7.94 (d, 2H, J = 6.8Hz), 7.78 (d, 2H, J = 6.8Hz), 7.52 (d, 1H, J = 6.8Hz), 7.46 (d, 1H, J = 6.8Hz),7.47-7.45(m,3H),7.03(d,1H,J=6.8Hz),6.92(d,1H,J=6.8Hz),6.82(s,1H),5.22(br,2H),4.46-4.42(m,2H),4.40-4.37(m,2H).

[0187] Synthesis of compound [DA-5]

[0188] Compound

[13] (4.13 g, 10.3 mmol) and 5% palladium carbon (0.41 g) were added to dimethylformamide (41 g) and stirred at room temperature for 25 hours under a hydrogen atmosphere. After nitrogen replacement, dimethylformamide (82 g) was added and heated to 120°C. The catalyst was filtered by hot filtration and the filtrate was concentrated to obtain a crude product (3.84 g). Dimethylformamide (19 g) was added to the crude product and heated to 100°C to dissolve it. Methanol (31 g) was then added little by little and cooled to precipitate crystals. The resulting liquid containing the crystals was filtered and the filtrate was dried to obtain compound [DA-5] (yield: 3.33 g, yield: 87%, brown crystals).

[0189] 1H-NMR (400 MHz, DMSO-d6, δ ppm): 7.51 (d, 1H, J = 6.8 Hz), 7.47-7.44 (m, 3H), 7.29 (d, 2H, J = 6.8 Hz), 7.16 (d, 1H, J = 1.6 Hz), 7.03-6.99 (m, 3H), 6.91 (dd, 1H, J = 6.8 Hz, 1.6 Hz), 6.80 (d, 1H, J = 1.6 Hz), 6.62 (d, 2H, J = 6.8 Hz), 5.11 (br, 4H), 4.35 (br, 4H).

[0190] 4. Synthesis example of compound [DA-14]

[0191] Compound [DA-14] was obtained by the same synthesis method as that of Compound [DA-3], except that 1,2-ethanediol was changed to 1,3-propanediol.

[0192] 5. Synthesis example of compound [DA-15]

[0193] Compound [DA-15] was obtained by the same synthesis method as that of Compound [DA-4], except that ethylene glycol ditosylate was changed to 1,3-propanediol ditosylate.

[0194] [Viscosity]

[0195] The measurement was performed using a viscometer TVE-22H (manufactured by Tokimec, Inc.) under the conditions of a sample amount of 1.1 mL, a cone-type rotor TE-1 (1° 34', R24), and a temperature of 25°C.

[0196] [Molecular weight]

[0197] The number average molecular weight (Mn) and the weight average molecular weight (Mw) were calculated as polyethylene glycol and polyethylene oxide conversion values by GPC (gel permeation chromatography) apparatus.

[0198] GPC apparatus: GPC-101 (manufactured by Shodex), chromatography column: KD803 and KD805 (manufactured by Shodex, connected in series), column temperature: 50°C, eluent: N,N-dimethylformamide (as additives, lithium bromide monohydrate (LiBr-H2O) 30 mmol / L, phosphoric acid anhydrous crystal (orthophosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 mL / L), flow rate: 1.0 mL / min

[0199] The standard samples used for the calibration curve preparation were: TSK standard polyethylene oxide manufactured by TOSOH CORPORATION (weight average molecular weight (Mw) of approximately 900,000, 150,000, 100,000, and 30,000) and polyethylene glycol manufactured by Polymer Laboratories Ltd. (peak molecular weight (Mp) of approximately 12,000, 4,000, and 1,000). To avoid peak overlap, two samples were measured: a mixture of four samples with Mw values ​​of 900,000, 100,000, 12,000, and 1,000, and a mixture of three samples with Mw values ​​of 150,000, 30,000, and 4,000.

[0200] [Determination of Imidization Ratio]

[0201] 20 mg of polyimide powder was placed in an NMR sample tube (NMR sample tube standard, φ5 (manufactured by Kusano Scientific Co., Ltd.)), deuterated dimethyl sulfoxide (DMSO-d6, 0.05% TMS (tetramethylsilane) mixture) (0.53 ml) was added, and ultrasonic waves were applied to completely dissolve the solution. This solution was measured for proton NMR at 500 MHz using an NMR analyzer (JNW-ECA500) (manufactured by JEOL DATUM Ltd.). The imidization rate was determined by using a proton derived from a structure that does not change before and after imidization as a reference proton, and the peak cumulative value of this proton and the peak cumulative value of the proton derived from the NH group of the amic acid appearing around 9.5 ppm to 10.0 ppm were used to determine the imidization rate according to the following formula.

[0202] Imidization rate (%) = (1-α·x / y) × 100

[0203] In the above formula, x is the peak cumulative value of protons derived from NH groups of amic acid, y is the peak cumulative value of reference protons, and α is the number ratio of reference protons to one NH group proton of amic acid in the case of polyamic acid (imidation rate 0%).

[0204] [Structure of FFS-driven liquid crystal unit]

[0205] For a liquid crystal cell for a fringe field switching (FFS) mode, a FOP (Finger on Plate) electrode layer formed of a surface-shaped common electrode-insulating layer-finger-shaped pixel electrode is formed on a first glass substrate of a surface, and a second glass substrate having a columnar spacer of a height of 4 μm on a surface and an ITO film for antistatic formed on a back surface as a set. The pixel electrode has a plurality of finger-shaped electrode elements each having a width of 3 μm and a bend of an inner angle of 160° arranged in parallel with a 6-μm interval, and one pixel has a first region and a second region with a line connecting the bends of the electrode elements as a boundary.

[0206] Note that the liquid crystal alignment film formed on the first glass substrate is subjected to alignment treatment in a manner that an inner angle bisector of the pixel bend is orthogonal to the alignment direction of the liquid crystal, and the liquid crystal alignment film formed on the second glass substrate is subjected to alignment treatment in a manner that the alignment direction of the liquid crystal on the first substrate coincides with the alignment direction of the liquid crystal on the second substrate at the time of manufacturing the liquid crystal cell.

[0207] [Manufacture of Liquid Crystal Cell]

[0208] On each surface of the above set of glass substrates, a liquid crystal alignment agent filtered with a filter having an aperture of 1.0 μm is applied by spin coating, and dried on a hot plate at 80°C for 2 minutes. Then, a prescribed amount of ultraviolet rays of a wavelength of 254 nm linearly polarized at an extinction ratio of 26:1 is irradiated to the coated surface by means of a polarizer, and then, baking is performed using a hot air circulating oven at 230°C for 30 minutes, to obtain a substrate with a liquid crystal alignment film having a film thickness of 100 nm.

[0209] Next, a sealing agent is printed on one of the above set of glass substrates with a liquid crystal alignment film, and the other substrate is attached with the liquid crystal alignment film surfaces opposed to each other, and the sealing agent is cured to manufacture an empty cell. To the empty cell, liquid crystal MLC-3019 (manufactured by Merck Ltd.) is injected by a reduced pressure injection method, and the injection port is sealed, to obtain an FFS-driven liquid crystal cell. Then, the obtained liquid crystal cell is heated at 120°C for 1 hour, and left overnight, and evaluation of residual image characteristics is performed.

[0210] [Evaluation of Residual Image Characteristics Due to Long-Term AC Drive]

[0211] To the above manufactured FFS-driven liquid crystal cell, an AC voltage of ±5 V is applied at a frequency of 60 Hz for 120 hours in a constant temperature environment at 60°C. Then, a state in which the pixel electrode and the counter electrode of the liquid crystal cell are short-circuited is formed, and left in this state at room temperature for one day.

[0212] For the liquid crystal cell subjected to the above treatment, the shift in the alignment direction of the liquid crystal in the first region of the pixel from the alignment direction of the liquid crystal in the second region in the no-voltage-applied state was calculated as an angle.

[0213] Specifically, the liquid crystal cell was disposed between two polarizing plates disposed in a crossed-nicole manner, the backlight was turned on, the disposition angle of the liquid crystal cell was adjusted in such a manner that the transmission light intensity of the first region of the pixel was the minimum, and then the rotation angle required to rotate the liquid crystal cell in such a manner that the transmission light intensity of the second region of the pixel was the minimum was found.

[0214] The smaller the value of the rotation angle, the better the residual image characteristics due to long-term AC driving can be said to be. The case where the value of the angle Δ of the liquid crystal cell was 0.1° or less was evaluated as "good".

[0215] [Synthesis Examples of Polyamic Acid and Polyimide]

[0216] The following shows synthesis examples of polyamic acid and polyimide. Note that in their names, A indicates the (A) component, B indicates the (B) component, C indicates neither the (A) component nor the (B) component, and PI indicates polyimide.

[0217] <SYNTHESIS EXAMPLE 1>

[0218] In a 200 mL four-necked flask equipped with a stirring device and a nitrogen gas inlet tube, DA-1 1.95 g (8.00 mmol), DA-2 1.30 g (12.0 mmol), DA-3 3.53 g (12.0 mmol), and DA-7 1.90 g (8.00 mmol) were taken, NMP 99.73 g was added, and stirring and dissolution were performed while supplying nitrogen gas. While the diamine solution was being stirred, CA-1 7.35 g (32.8 mmol) and CA-2 1.50 g (6.0 mmol) were added, and stirring was performed at 40°C for 24 hours, to thereby obtain a polyamic acid solution (A-1) (viscosity: 460 mPa-s). The molecular weight of the polyamic acid was Mn = 9100, Mw = 28000.

[0219] <SYNTHESIS EXAMPLES 2 to 11, 16 to 19>

[0220] The diamine component and the tetracarboxylic acid component were changed to the components shown in Table 1 below, and the same as in Synthesis Example 1 was performed, to thereby obtain the polyamic acid solutions (A-2) to (A-11), (B-1) to (B-4) shown in Table 1 below. The viscosity and the molecular weight of the obtained polyamic acid are shown in Table 1 below.

[0221] [Table 1]

[0222]

[0223] <SYNTHESIS EXAMPLE 12>

[0224] To 100 g of the obtained polyamic acid solution (A-1) in a 3L four-necked flask equipped with a stirrer and a nitrogen gas inlet tube, 50 g of NMP was added, and stirring was performed for 30 minutes. To the obtained polyamic acid solution, 16.30 g of acetic anhydride and 5.05 g of pyridine were added, and chemical imidization was performed by heating at 50°C for 3 hours. While stirring, the obtained reaction solution was poured into 600 ml of methanol, and the precipitated solid was filtered, and the same operation was performed twice to wash the resin powder, and then the resin powder was dried at 60°C for 12 hours to obtain a polyimide resin powder. The imidization ratio of the obtained polyimide resin powder was 71%, Mn = 11000, and Mw = 38000. To 3.60 g of the obtained polyimide resin powder in a 100 ml conical flask, 26.4 g of NMP was added so as to form a solid content concentration of 12%, and dissolution was performed by stirring at 70°C for 24 hours to obtain a polyimide solution (A-1-PI) (see Table 2 below).

[0225] <SYNTHESIS EXAMPLES 13 to 15, 20 to 21>

[0226] Instead of the polyamic acid solution (A-1), the polyamic acid of Table 2 below was used, and the imidization conditions were changed to the imidization conditions of Table 2 below, and otherwise the same as in Synthesis Example 8 to obtain a polyimide solution (A-2-PI) to a polyimide solution (A-11-PI). The molecular weight of the obtained polyimides is shown in Table 2 below.

[0227] [Table 2]

[0228]

[0229] [Manufacture of liquid crystal aligning agent]

[0230] <Example 1>

[0231] To 4.0 g of the 12 mass% polyimide solution (A-1-PI) obtained in Synthesis Example 12 and 4.8 g of the 15 mass% polyamic acid solution (B-1) obtained in Synthesis Example 10 in a 50 ml conical flask, 1.20 g of NMP, 6.00 g of GBL, and 4.00 g of BCS were added, and mixed at 25°C for 8 hours to obtain a liquid crystal aligning agent (1) (see Table 3 below). The liquid crystal aligning agent did not show turbidity, precipitation, or the like, and was confirmed to be a uniform solution.

[0232] <Examples 2 to 16, Comparative Examples 1 to 2>

[0233] Instead of the polyimide solution (A-1-PI) and the polyamic acid solution (B-1), the polyamic acid solutions and the polyimide solutions of Table 3 below were used, and otherwise similarly to Example 1, to thereby obtain liquid crystal alignment agents (2) to (18). No abnormalities such as turbidity, precipitation, etc. were found in these liquid crystal alignment agents, and they were confirmed to be uniform solutions.

[0234] [Table 3]

[0235]

[0236] [Results of evaluation of afterimage due to long-term AC drive (in the case where baking was performed before ultraviolet irradiation)]

[0237] Example 21

[0238] After the liquid crystal alignment agent (1) of Example 1 was filtered using a filter having a pore size of 1.0 μm, it was applied to the prepared above-mentioned electrode-equipped substrate and a glass substrate having a columnar spacer with a height of 4 μm, on the back surface of which an ITO film was formed, using spin coating. After drying on a hot plate at 80°C for 2 minutes, baking was performed using a hot air circulation oven at 230°C for 30 minutes, to thereby form a coating film having a film thickness of 100 nm. After the coating film surface was irradiated with ultraviolet rays of wavelength 254 nm, which were linearly polarized with an extinction ratio of 26:1, using a hot air circulation oven at 230°C for 30 minutes, a substrate having a liquid crystal alignment film was obtained. The obtained two above-mentioned substrates were used as one set, a sealant was printed on the substrates, and the other substrate was attached with the liquid crystal alignment film surface facing each other, with the alignment direction being formed at 0°, to thereby produce a cell after the sealant was cured. Liquid crystal MLC-3019 (manufactured by Merck Ltd.) was injected into the cell by a reduced-pressure injection method, the injection port was sealed, and an FFS-driven liquid crystal cell was obtained. The obtained liquid crystal cell was then heated at 120°C for 1 hour, left to stand overnight, and evaluation of afterimage due to long-term AC drive was performed. The value of the angle Δ of the liquid crystal cell after long-term AC drive was 0.09° in the case where the irradiation amount of the above-mentioned ultraviolet rays was 200 mJ / cm 2 , 0.1° in the case where it was 300 mJ / cm 2 , and 0.1° in each case, and thus good liquid crystal alignment properties were obtained using the liquid crystal alignment agent (1) (see Table 4 below).

[0239] Examples 22 to 32, Comparative Examples 21 and 22

[0240] Instead of the liquid crystal alignment agent (1) of Example 1, the liquid crystal alignment agents shown in Table 4 below were used, and the amount of ultraviolet irradiation was changed to that of Table 4 below, and otherwise, a FFS drive liquid crystal cell was produced by the same method as Example 21, and evaluation of residual image due to long-term AC drive was performed. The value of the angle Δ of the liquid crystal cell after each long-term AC drive is shown in Table 4.

[0241] [Table 4]

[0242]

[0243] [Results of evaluation of residual image due to long-term AC drive (in the case where no baking was performed before ultraviolet irradiation)]

[0244] Example 41

[0245] After the liquid crystal alignment agent (1) of Example 1 was filtered using a filter having a pore size of 1.0 μm, it was applied to the prepared above-mentioned electrode-equipped substrate and a glass substrate having a columnar spacer having a height of 4 μm on which an ITO film was formed on the back surface, using spin coating. After drying on a hot plate at 80°C for 2 minutes, to the coated film surface, ultraviolet rays of wavelength 254 nm, which were linearly polarized at an extinction ratio of 26:1, were irradiated using a polarizing plate, and then baking was performed using a hot air circulation oven at 230°C for 30 minutes, to obtain a substrate having a liquid crystal alignment film with a film thickness of 100 nm. The obtained two above-mentioned substrates were used as one set, a sealant was printed on the substrates, and the other substrate was attached with the liquid crystal alignment film surface facing each other, with the alignment direction being 0°, and after the sealant was cured, a cell was produced. To the cell, liquid crystal MLC-3019 (manufactured by Merck Ltd.) was injected by a reduced pressure injection method, and the injection port was sealed, to obtain a FFS drive liquid crystal cell. Then, the obtained liquid crystal cell was heated at 120°C for 1 hour, and left overnight, and evaluation of residual image due to long-term AC drive was performed. The value of the angle Δ of the liquid crystal cell after long-term AC drive was 0.07° in the case where the amount of irradiation of the above-mentioned ultraviolet rays was 200 mJ / cm 2 , 0.07° in the case where it was 300 mJ / cm 2 , and both were 0.1° or less, and thus good liquid crystal alignment properties were obtained using the liquid crystal alignment agent (1) (see Table 5 below)

[0246] Examples 42 to 49, Comparative Examples 41 and 42

[0247] Instead of the liquid crystal alignment agent (1) of Example 1, a liquid crystal alignment agent shown in Table 5 below was used, and the amount of ultraviolet irradiation was changed to the amount of ultraviolet irradiation of Table 5 below, and otherwise, a FFS drive liquid crystal cell was produced by the same method as Example 41, and evaluation of afterimage due to long-term AC drive was performed. The value of the angle Δ of the liquid crystal cell after each long-term AC drive is shown in Table 5.

[0248] [Table 5]

[0249]

[0250] As shown in Table 4 and Table 5, Examples 1 to 12 are excellent in improvement of display quality of the liquid crystal display element because the angle Δ (deg.) is an angle Δ of 0.1° or less, and the afterimage characteristics are good.

[0251] Industrial applicability

[0252] The liquid crystal alignment agent of the present application is used in a wide range of fields such as large-sized liquid crystal display elements, mobile liquid crystal display elements such as smartphones and portable telephones, and the like, which require high refinement and low cost.

[0253] Note that the specification, claims, drawings, and abstract of Japanese Patent Application No. 2018-196761 filed on October 18, 2018 are hereby incorporated by reference in their entirety as the disclosure of the present application.

Claims

1. A liquid crystal alignment agent, characterized in that: It contains at least one polymer selected from the group consisting of polyamic acid and polyimide obtained by imidizing the polyamic acid, wherein the polyamic acid is obtained by reacting a diamine component containing a diamine having the structure shown below with a tetracarboxylic dianhydride component, 2. The liquid crystal aligning agent according to claim 1, wherein The content of the diamine having the structure shown above in the diamine component is 5 to 95 mol%.

3. The liquid crystal aligning agent according to claim 1 or 2, wherein The tetracarboxylic dianhydride component is tetracarboxylic dianhydride or a derivative thereof represented by the following formula [7], In formula [7], Z1 is a tetravalent organic group.

4. The liquid crystal aligning agent according to claim 3, wherein Z1 is any of the structures represented by any of the following formulae (X1-1) to (X1-19), In formula (X1-1) and (X1-2), R3 to R 12 Each of R3 to R6 is independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group, wherein at least one of R3 to R6 is a group other than a hydrogen atom.

5. The liquid crystal alignment agent according to claim 4, wherein Z1 is a structure represented by formula (X1-1). 6 . A liquid crystal alignment film obtained from the liquid crystal alignment agent according to claim 1 . A liquid crystal display element comprising the liquid crystal aligning film according to claim 6 .

8. A diamine having the structure shown below,

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