Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element

Abstract

This invention provides a liquid crystal alignment agent capable of forming a liquid crystal alignment film with a high voltage retention rate, and capable of suppressing image retention caused by long-term AC driving and reducing the accumulated charge within liquid crystal cells caused by liquid crystal driving in a short time, and provides suitable novel diamines and polymers for these. A liquid crystal alignment agent comprises a polymer selected from the group consisting of a polyimide precursor obtained using a diamine component containing a diamine represented by the following formula (DA) and a polyimide that is a polyimide derivative of the polyimide precursor. The definitions of each designation are as described in the specification.

Description

Technical Field

[0001] This invention relates to liquid crystal alignment agents, liquid crystal alignment films obtained from the liquid crystal alignment agents, liquid crystal display elements having the liquid crystal alignment films, and novel diamines and polymers suitable for them. Prior Technology

[0002] Liquid crystal display (LCD) elements are widely used in applications ranging from small devices like mobile phones and smartphones to larger applications such as televisions and monitors. Furthermore, various driving methods have been developed, including different electrode structures and the physical properties of the liquid crystal molecules used. Examples include LCD elements employing TN (Twisted Nematic), STN (Super Twisted Nematic), VA (Vertical Alignment), IPS (In-Plane Switching), and FFS (Fringe Field Switching). These LCD elements generally possess a liquid crystal alignment film, essential for controlling the alignment of liquid crystal molecules. Considering factors such as heat resistance, mechanical strength, and liquid crystal affinity, polyamide and polyimide are commonly used for the materials of the liquid crystal alignment film.

[0003] For liquid crystal display elements, high display quality is required, such as high voltage retention rate, which is one of the required characteristics. To this end, Patent Document 1 discloses a composition for liquid crystal alignment films containing aromatic diamines such as 1,5-bis(4-aminophenoxy)pentane. [Previous Technical Documents] [Patent Literature]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 06-194670 Summary of the Invention

[0005] (The problem the invention aims to solve)

[0006] In recent years, with the increasing performance of liquid crystal display (LCD) elements, in addition to large-screen and high-resolution LCD televisions, research has been conducted on their application in automotive applications, such as car navigation systems, dashboards, surveillance cameras, and medical camera screens. Therefore, the requirements for LCD elements, especially high resolution and high performance, are even higher, and the requirements for liquid crystal alignment films are more stringent in terms of various characteristics of the LCD elements.

[0007] One objective of this invention is to form a liquid crystal alignment film with a high voltage retention rate, which suppresses the occurrence of display defects such as image burn-in (image burn-in of areas and lines), spots, or dirt caused by external stimuli such as light and temperature over time, thereby bringing about conditions for long-term reliability of display quality. Another objective is to provide a liquid crystal alignment agent that can form a liquid crystal alignment film that can suppress image retention (hereinafter also referred to as AC image retention) caused by long-term AC driving and reduce the charge accumulation in the liquid crystal cells caused by liquid crystal driving in a short time, as well as a liquid crystal display element having the liquid crystal alignment film, and novel diamines and polymers suitable for them. (Methods for solving problems)

[0008] In order to achieve the above-mentioned objectives, the inventors of this invention conducted extensive research and discovered that liquid crystal alignment agents containing polymers of novel diamines with specific structures are effective in achieving the above objectives, thus completing this invention.

[0009] The present invention relates to a liquid crystal alignment agent, characterized in that it contains a polymer (P), which is selected from at least one of the group consisting of a polyimide precursor obtained by using a diamine component containing a diamine (O) represented by the following formula (DA) and a polyimide that is a polyimide derivative of the polyimide precursor, and is a liquid crystal alignment film obtained by the liquid crystal alignment agent and a liquid crystal display element having the liquid crystal alignment film. [Chemistry 1] In the above formula, R represents a hydrogen atom or a methyl group. L independently represents a single bond or a divalent linkage group; when L has a carbon atom, it represents a divalent organic group with 1 to 14 carbon atoms. Ar independently represents a divalent aromatic group. n is an integer from 6 to 20.

[0010] Furthermore, in this invention, halogen atoms may include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc., and * indicates an atomic bond. Boc represents a third butoxycarbonyl group. (Effects of the invention)

[0011] According to the present invention, a liquid crystal alignment agent that forms a liquid crystal alignment film with high voltage retention and suppresses image retention, and can reduce the accumulated charge in a short time, a liquid crystal alignment film obtained from the liquid crystal alignment agent, a high-performance liquid crystal display element having the liquid crystal alignment film, and novel diamines and polymers used in the manufacture of the same are obtained.

[0012] The mechanism by which the above-mentioned effects of the present invention are obtained is not clear, but it is generally presumed to be as follows: It is believed that by introducing a specific alkyl glycol chain into a specific diamine, the elongation of the membrane is improved, thus obtaining the above-mentioned effects. Implementation

[0013] <Specific diamine> The liquid crystal alignment agent of the present invention, as described above, is characterized by containing a polymer (P), which is selected from at least one of the following groups: a polyimide precursor obtained by using a diamine component containing a diamine (O) represented by the above formula (DA) (also referred to as a specific diamine in the present invention); and a polyimide constituting a polyimide of the polyimide precursor.

[0014] The diamine represented by the above formula (DA) can be one type of diamine or multiple types of diamines.

[0015] In the above formula (DA), L independently represents a single bond or a divalent group. Examples of divalent groups in L in the above formula (DA) include: -C(=O)-, -OC(=O)-, -NR 1-C(=O)- (R 1 represents a hydrogen atom or a methyl group), -NR 1-C(=O)-NR 1-C(=O)- (R 1 independently represents a hydrogen atom or a methyl group), or *1-L'-GL”-*2. G represents a hydrocarbon group with 1 to 6 carbon atoms. L' represents a single bond, -O-, -C(=O)-, -OC(=O)-, -NR 2-C(=O)- (R 2 represents a hydrogen atom or a methyl group), -NR 2- (R 2 represents a hydrogen atom or a methyl group), or -NR 2-C(=O)-NR 2- (R 2 independently represents a hydrogen atom or a methyl group). "L" indicates a single bond, -C(=O)-, -OC(=O)-, -NR 3-C(=O)- (R 3 represents a hydrogen atom or a methyl group), -NR 3-C(=O)-NR 3-C(=O)- (R 3 independently represents a hydrogen atom or a methyl group), or -NR 3-C(=O)-C(=O)- (R 3 represents a hydrogen atom or a methyl group). *1 represents an atomic bond with Ar. *2 represents an atomic bond with oxygen.

[0016] In the above formula (DA), each Ar independently represents a divalent aromatic group. The divalent aromatic group in Ar can also be any of a divalent aromatic hydrocarbon group or a divalent aromatic heterocyclic group. The above aromatic group can be either monocyclic or polycyclic, and the number of atoms constituting its ring skeleton (ring members) is not particularly limited, but 3 to 20 is preferred.

[0017] The divalent aromatic hydrocarbon groups mentioned above can be categorized as divalent groups that have removed two hydrogen atoms from an aromatic hydrocarbon (benzene ring, naphthalene ring, etc.), or divalent hydrocarbon groups formed by the connection of two aromatic hydrocarbon atoms by a single bond. The divalent aromatic heterocyclic groups mentioned above can be categorized as divalent groups that have removed two hydrogen atoms from aromatic heterocycles (e.g., pyridine ring, pyrimidine ring, pyridine ring, triphenyl ring, pyrrole ring, imidazole ring, pyrazole ring, quinoline ring, isoquinoline ring, carbazole ring, benzimidazole ring, indole ring, quinoline ring, acridine ring, etc.).

[0018] Furthermore, the aforementioned aromatic hydrocarbon groups and aromatic heterocyclic groups may also have substituents. Here, "may also have substituents" means that one or more hydrogen atoms constituting the aromatic hydrocarbon group or aromatic heterocyclic group may be replaced by groups other than hydrogen atoms (substituents). Examples of substituents include methyl, methoxy, trifluoromethyl, halogen atom, carboxyl, hydroxyl, cyano, and nitro.

[0019] The divalent aromatic group in Ar of the above formula (DA) is preferably a divalent group from which two hydrogen atoms have been removed from a benzene ring, biphenyl structure, naphthyl ring, pyridine ring, pyrimidine ring, pyridine ring, triphenyl ring, pyrrole ring, imidazole ring, pyrazole ring, quinoline ring, isoquinoline ring, carbazole ring, benzimidazole ring, indole ring, quinoline ring, or acridine ring.

[0020] The diamine represented by the above formula (DA) is preferably represented by the following formula (D a). [Chemistry 2]

[0021] In the above formula (DA), L, R, and n are synonyms with L, R, and n in the above formula (DA). The hydrogen atoms on the benzene ring can also be replaced by monovalent groups.

[0022] In the above formulas (DA) and (D a), n is an integer from 6 to 20. Considering the viewpoint of obtaining high liquid crystal alignment, 6 to 18 is better, and 6 to 16 is even better.

[0023] In the above formulas (DA) and (D a), the specific examples of the hydrocarbon group in *1-L'-GL”-*2 of G are, for example, chain hydrocarbons with 1 to 6 carbon atoms such as alkanes such as methane, ethane, propane, and butane; alkenes such as ethylene, propylene, butene, and pentene; alkynes such as acetylene, propyne, butyne, and pentyne; cycloalkanes such as cyclopropane, cyclobutane, cyclopentane, and cyclohexane; cycloalkenes such as cyclopropylene, cyclobutene, cyclopentene, and cyclohexene; alicyclic hydrocarbons with 3 to 6 carbon atoms such as cycloalkenes; and aromatic hydrocarbons such as benzene.

[0024] In the above formulas (DA) and (Da), L represents the ideal effect of the present invention, especially single bonds, -C(=O)-, -OC(=O)-, and -NR 1-C(=O)- (R 1 represents a hydrogen atom or a methyl group).

[0025] The hydrogen atoms on the benzene ring in formula (D a) can also be replaced by monovalent groups, such as methyl, methoxy, trifluoromethyl, halogen atoms, carboxyl, hydroxyl, cyano, and nitro groups. Among these, halogen atoms are preferred.

[0026] In the above formula (D a), considering the viewpoint of obtaining high liquid crystal alignment, the two amine groups are preferably para-positioned, which is better than the divalent organic group that links the benzene ring.

[0027] An ideal example of the above equation (D a) can be listed as the following equations (d a-1)~(d a-3). [Chemistry 3] In the formula, n is an integer from 6 to 20. Hydrogen atoms on the benzene ring can also be substituted with monovalent groups.

[0028] The hydrogen atoms on the benzene ring in formulas (da-1) to (da-3) can also be replaced by monovalent groups, such as methyl, methoxy, trifluoromethyl, halogen atoms, carboxyl, hydroxyl, cyano, and nitro groups. Among these, halogen atoms are preferred.

[0029] (Polymer(P)) The polymer (P) contained in the liquid crystal alignment agent of the present invention is a polyimide precursor obtained using a diamine component containing the above-mentioned diamine (0), or a polyimide of a amide of the polyimide precursor. The polyimide precursor is a polymer such as polyamide or polyamide ester that can be amide-modified to obtain polyimide. Polyamide (P'), the polyimide precursor of the above polymer (P), can be obtained by polymerization of a diamine component containing the above diamine (0) and a tetracarboxylic acid component. The above diamine (0) can be used alone or in combination of two or more. The amount of diamine (0) used relative to the total diamine content is ideally 1 mol% or more, 2 mol% or more is better, and 3 mol% or more is even better.

[0030] The diamine component used in the manufacture of the above-mentioned polyamide (P') may also contain diamines other than diamine (0) (hereinafter also referred to as other diamines). When other diamines are used in addition to the above-mentioned diamine (0), the amount of diamine (0) used relative to the diamine component is ideally 99 mol% or less, preferably 98 mol% or less, and even better 97 mol% or less.

[0031] Examples of other diamines are listed below, but are not limited to these. The aforementioned other diamines may be used alone or in combination of two or more.

[0032] p-Phenylenediamine, 2,3,5,6-Tetramethyl-p-phenylenediamine, 2,5-Dimethyl-p-phenylenediamine, m-Phenylenediamine, 2,4-Dimethyl-m-phenylenediamine, 2,5-Diaminotoluene, 2,6-Diaminotoluene, 2,2'-Dimethyl-4,4'-Diaminobiphenyl, 3,3'-Dimethyl-4,4'-Diaminobiphenyl, 3,3'-Dimethoxy-4,4'-Diaminobiphenyl, 3,3'-Dihydroxy-4,4'-Diamine 2,2'-difluoro-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 4,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'-diaminobiphenyl, 2,3'-diaminobiphenyl, and the following formula (d AL-1)~(d AL-10) represents diamines, 1,7-bis(4-aminophenoxy)heptane, 1,7-bis(3-aminophenoxy)heptane, 1,8-bis(4-aminophenoxy)octane, 1,8-bis(3-aminophenoxy)octane, 1,9-bis(4-aminophenoxy)nonane, 1,9-bis(3-aminophenoxy)nonane, 1,10-bis(4-aminophenoxy)decane, 1,10-bis(3-aminophenoxy)decane, 1,11-bis(4-aminophenoxy)undecane, 1,11-bis(3-aminophenoxy)undecane, 1,12-bis(4-aminophenoxy)dodecane, 1,12-bis(3-aminophenoxy)dodecane, 1,4-bis... (4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)diphenyl ether, 1,4-bis[4-(4-aminophenoxy)phenoxy]benzene, 1,2-bis(6-amino-2-naphthyl)ethane, 1,2-bis(6-amino-2-naphthyl)ethane, 6-[2-(4-aminophenoxy)ethoxy]-2-naphthylamine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene (hereinafter collectively referred to as diamines (ph)).); 1,4-Phenylbis(4-aminobenzoate), 1,4-Phenylbis(3-aminobenzoate), 1,3-Phenylbis(4-aminobenzoate), 1,3-Phenylbis(3-aminobenzoate), bis(4-aminophenyl)terephthalate, bis(3-aminophenyl)terephthalate, bis(4-aminophenyl)isophthalate, bis(3-aminophenyl)isophthalate; diamines with photoaligning groups such as 4,4'-diaminoazobenzene or diaminodiphenylacetylene; diamines with photopolymerizable groups at the end such as 2-(2,4-diaminophenoxy)ethyl methacrylate or 2,4-diamino-N,N-diallyl aniline methacrylate; 1-(4-( Diamines with free radical polymerization initiator functions, such as 2-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylpropanone and 2-(4-(2-hydroxy-2-methylpropoxy)ethyl 3,5-diaminobenzoic acid; diamines with amide bonds, such as 4,4'-diaminophenoxyaniline; diamines with urea bonds, such as 1,3-bis(4-aminophenyl)urea, 1,3-bis(4-aminobenzyl)urea, and 1,3-bis(4-aminophenylethyl)urea; 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(3-aminophenyl)hexafluoropropane, 2, 2-Bis(3-amino-4-methylphenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(3-amino-4-methylphenyl)propane, 4,4'-diaminodiphenyl ketone, 1,4-bis(4-aminobenzyl)benzene; 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N-[3-(1H-imidazol-1-yl)propyl]-3,5-diaminobenzylamine, 4 -[4-[(4-aminophenoxy)methyl]-4,5-dihydro-4-methyl-2-azolyl]-aniline, or diamines containing heterocycles such as those represented by formulas (z-1) to (z-13), or diamines with a diphenylamine structure such as 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl-N-methylamine, N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine, or N,N'-bis(4-aminophenyl)-N,N'-dimethyl-1,4-phenylenediamine, are representative of diamines with a diphenylamine structure having at least one nitrogen-containing atom selected from the group consisting of heterocycles, secondary amine groups, and tertiary amine groups (hereinafter also referred to as specific nitrogen-containing structures).(The diamines mentioned above are excluded, except that they do not contain an amino group that has been decoupled and replaced by a hydrogen atom by heating.) 2,4-Diaminophenol, 3,5-Diaminophenol, 3,5-Diaminobenzyl alcohol, 2,4-Diaminobenzyl alcohol, 4,6-Diaminoresorcinol, 4,4'-Diamino-3,3'-Dihydroxybiphenyl; 2,4-Diaminobenzoic acid, 2,5-Diaminobenzoic acid, 3,5-Diaminobenzoic acid, 4,4'-Diaminobiphenyl-3-carboxylic acid, 4,4'-Diaminodiphenylmethane-3-carboxylic acid, 1,2-bis(4-aminophenyl)ethane-3-carboxylic acid, Diamines containing carboxyl groups, such as 4,4'-diaminobiphenyl-3,3'-dicarboxylic acid, 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid, 3,3'-diaminobiphenyl-4,4'-dicarboxylic acid, 3,3'-diaminobiphenyl-2,4'-dicarboxylic acid, 4,4'-diaminodiphenylmethane-3,3'-dicarboxylic acid, 1,2-bis(4-aminophenyl)ethane-3,3'-dicarboxylic acid, and 4,4'-diaminodiphenyl ether-3,3'-dicarboxylic acid; and 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, and 1-(4-aminophenyl)-1,3,3-trimethyl-1H-dihydroindene. -5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine; diamines of formulas (5-1)~(5-6) having the group "-N(D)-" (D represents a protecting group that is removed and replaced by a hydrogen atom upon heating, preferably a carbamate protecting group, more preferably a tert-butoxycarbonyl group), cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, lanostane 3,6-diaminobenzoate, and cholesteryl 3,6-diaminobenzoate. -Diamines having a steroid skeleton, such as bis(4-aminobenzoyloxy)cholestane; diamines represented by formulas (V-1) to (V-2); diamines having a siloxane bond, such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane; diamines with two amino groups represented by any of the formulas (Y-1) to (Y-167) disclosed in International Publication No. 2018 / 117239.

[0033] [Chemistry 4]

[0034] [Chemistry 5]

[0035] [Chemistry 6]

[0036] [Chemistry 7]

[0037] [Chemistry 8] In equation (V-1) above, m and n are integers from 0 to 3, and satisfy 1 ≤ m + n ≤ 4. j is an integer of 0 or 1. X1 represents -(CH2)a- (a is an integer from 1 to 15), -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -CH2O-, -CH2-OCO-, -COO-, or -OCO-. R1 represents a fluorine atom, an alkyl group containing fluorine atoms with 1 to 10 carbon atoms, an alkoxy group containing fluorine atoms with 1 to 10 carbon atoms, an alkyl group with 1 to 10 carbon atoms, an alkoxy group with 1 to 10 carbon atoms, and an alkoxyalkyl group with 2 to 10 carbon atoms, etc., all of which are monovalent groups. In equation (V-2) above, X2 represents -O-, -CH2O-, -CH2-OCO-, -COO-, or -OCO-. When two of m, n, X1, and R1 exist, each of them independently possesses the above definition.

[0038] When other diamines are used in addition to the diamine (0) mentioned above, the amount of the other diamine used relative to the total diamine component used is preferably 1 to 99 mol%, more preferably 2 to 98 mol%, and even more preferably 3 to 97 mol.

[0039] From the perspective of improving the alignment of liquid crystals, the other diamines mentioned above can also be at least one diamine selected from the diamines (ph) mentioned above.

[0040] (Tetracarboxylic acid component) When manufacturing the above-mentioned polyamide (P'), the tetracarboxylic acid component that reacts with the diamine component can be not only tetracarboxylic dianhydride, but also derivatives of tetracarboxylic dianhydride such as tetracarboxylic acid, tetracarboxylic acid dihalides, tetracarboxylic acid dialkyl esters, or tetracarboxylic acid dialkyl ester dihalides.

[0041] The aforementioned tetracarboxylic dianhydrides or their derivatives may include acyclic aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, aromatic tetracarboxylic dianhydrides, or derivatives thereof. It is preferable that the tetracarboxylic dianhydrides or their derivatives contain at least one substructure selected from the group consisting of a benzene ring, a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring. It is particularly desirable that the tetracarboxylic dianhydrides or their derivatives contain at least one structure selected from the group consisting of a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring. The tetracarboxylic acid dianhydride or its derivatives in the tetracarboxylic acid component may be one or more.

[0042] The tetracarboxylic acid components that can be used in the manufacture of the above-mentioned polyacrylic acid (P') are preferably tetracarboxylic dianhydrides or their derivatives (in this invention, they are also collectively referred to as specific tetracarboxylic acid derivatives). Acyclic aliphatic tetracarboxylic anhydrides such as 1,2,3,4-butanetetracarboxylic anhydride; 1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,3-dichloro-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,3-difluoro-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,3-bis(trifluoromethyl)-1,2,3,4-cyclobutanetetracarboxylic anhydride, 1,2 3,4-Cyclopentanetetracarboxylic anhydride, 1,2,4,5-Cyclohexanetetracarboxylic anhydride, 3,3',4,4'-Dicyclohexyltetracarboxylic anhydride, 2,3,5-Tricarboxycyclopentylacetic anhydride, 4-(2,5-di-side-oxytetrahydrofuran-3-yl)tetrahydronaphthyl-1,2-dicarboxylic anhydride, 5-(2,5-di-side-oxytetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-di-side-oxytetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1 3-Diketone, bicyclic [2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, bicyclic [2.2.2]octane-2,3,5,6-tetracarboxylic dianhydride, 2,4,6,8-tetracarboxylic bicyclic [3.3.0]octane-2:4,6:8-dianhydride and other alicyclic tetracarboxylic dianhydrides; benzopyrene dianhydride, 3,3',4,4'-diphenyl ketone tetracarboxylic dianhydride, 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3',4,4'-diphenyl ether tetracarboxylic dianhydride, 3,3' Aromatic tetracarboxylic acid dianhydrides such as 4,4'-biphenyltetracarboxylic acid dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)-2,2-diphenylpropane dianhydride, ethylene glycol bis(triphenylene oxide) anhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 4,4'-carbonyldiphthalic anhydride, 4,4'-(1,4-epylphenyldioxy)bis(phthalic anhydride), or 4,4'-(1,4-epylphenyldimethyl)bis(phthalic anhydride); in addition, tetracarboxylic acid dianhydrides as described in Japanese Patent Application Publication No. 2010-97188, etc.

[0043] Ideal examples of the aforementioned specific tetracarboxylic acid derivatives include 1,2,3,4-butanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3 -Difluoro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-bis(trifluoromethyl)-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3',4,4'-dicyclohexyltetracarboxylic dianhydride, 2,3,5-tricarboxylated cyclopentylacetic acid dianhydride, 5-(2,5-disideloxytetrahydrofuran) 5-(2,5-di-side-oxytetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxylic acid bicyclo[3.3.0]octane-2:4,6:8-dianhydride, benzopyrene dicarboxylic acid ... Anhydride, 3,3',4,4'-diphenyl ketone tetracarboxylic anhydride, 3,3',4,4'-diphenyl ether tetracarboxylic anhydride, 1,4,5,8-naphthalene tetracarboxylic anhydride, 2,3,6,7-naphthalene tetracarboxylic anhydride, 3,3',4,4'-diphenyl ether tetracarboxylic anhydride, 3,3',4,4'-biphenyl tetracarboxylic anhydride, 2,2',3,3'-biphenyl tetracarboxylic anhydride, or derivatives thereof.

[0044] The ideal proportion of the aforementioned specific tetracarboxylic acid derivatives relative to the total tetracarboxylic acid components used is 0 mol% or more, 20 mol% or more is better, and 50 mol% or more is even better.

[0045] (Liquid crystal alignment agent) The liquid crystal alignment agent of the present invention is a liquid composition formed by ideally dispersing or dissolving a polymer (P) and other components as needed in a suitable solvent. The content (concentration) of the polymer component in the liquid crystal alignment agent of the present invention can be appropriately changed according to the desired coating thickness. Considering the formation of a uniform and defect-free coating, it is more ideal to have a content of 1% by mass or more relative to the total amount of the liquid crystal alignment agent. Considering the storage stability of the solution, it is better to have a content of 10% by mass or less. From the viewpoint of ideally achieving the effects disclosed herein, the proportion of polymer (P) in the liquid crystal alignment agent is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably 50 parts by mass or more, relative to 100 parts by mass of the total polymer content in the liquid crystal alignment agent. When the liquid crystal alignment agent contains other polymers described later, the proportion of polymer (P) relative to 100 parts by mass of the polymer component in the liquid crystal alignment agent is preferably 10 to 90 parts by mass, and more preferably 20 to 80 parts by mass.

[0046] The liquid crystal alignment agent of the present invention may also contain polymers other than polymer (P). Specific examples of other polymers include, in addition to polymer (P) mentioned above, polymers selected from the following group: polymers selected from at least one of the following groups consisting of a polyimide precursor obtained using a diamine component that does not contain a specific diamine and a polyimide that is a polyimide derivative of the polyimide precursor (also referred to as polymer (B) in the present invention), polysiloxanes, polyesters, polyamides, polyureas, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene derivatives, poly(styrene-maleic anhydride) copolymers, poly(isobutylene-maleic anhydride) copolymers, poly(vinyl ether-maleic anhydride) copolymers, poly(styrene-phenylmaleimide) derivatives, and poly(meth)acrylates.

[0047] Specific examples of poly(styrene-maleic anhydride) copolymers include SMA1000, SMA2000, SMA3000 (manufactured by Cray Valley), and GSM301 (manufactured by GIFUSHELLAC). Specific examples of poly(isobutylene-maleic anhydride) copolymers include ISOBAM-600 (manufactured by Kuraray). Specific examples of poly(vinyl ether-maleic anhydride) copolymers include Gantrez AN-139 (methyl vinyl ether maleic anhydride resin, manufactured by Ashland). Among these, considering the reduction of residual DC artifacts, polymer (B) is more ideal. The other polymers mentioned above can be used alone or in combination of two or more. Ideally, the proportion of the other polymers should be less than 90 parts by mass relative to the total number of polymers in the liquid crystal alignment agent (100 parts by mass), 10-90 parts by mass is better, and 20-80 parts by mass is even better.

[0048] (Polymer(B)) Specific examples of the tetracarboxylic acid component used in the manufacture of the polymer (B), including ideal examples, are the same compounds as those exemplified in polymer (P). The tetracarboxylic acid component used in the manufacture of polymer (B) is preferably a tetracarboxylic dianhydride or a derivative thereof having at least one substructure selected from the group consisting of a benzene ring, a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring. Such specific tetracarboxylic acid derivatives are even more desirable, and even more desirable examples of such specific tetracarboxylic acid derivatives are most desirable. Furthermore, the amount of the aforementioned specific tetracarboxylic acid derivative used is ideally 10 mol% or more relative to the total tetracarboxylic acid content used in the manufacture of polymer (B), preferably 20 mol% or more, and even more than 50 mol% or more.

[0049] The diamine component used to obtain polymer (B) is, for example, the diamine exemplified in the polymer (P) described above. Preferably, it contains at least one diamine selected from the group consisting of a urea bond, a amide bond, a carboxyl group, and a hydroxyl group, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, diamines represented by formulas (dAL-1) to (dAL-10) above, and at least one diamine from the group consisting of diamines having a specific nitrogen-containing structure (also referred to in this invention as specific diamines (b)). The aforementioned diamine component can be used alone or in combination of two or more diamines. When using the specific diamine (b) mentioned above, it is ideal to use at least 10 mol% of the total diamine content used in the manufacture of polymer (B), and more preferably at least 20 mol%. When using diamines other than the specific diamine (b), it is ideal to use at least 90 mol% of the total diamine content used in the manufacture of polymer (B), and more preferably at least 80 mol%.

[0050] (Manufacturing of polyacrylic acid) Polyamide is manufactured by reacting a diamine with a tetracarboxylic acid in an organic solvent. For the ratio of tetracarboxylic acid to diamine used in the polyamide manufacturing reaction, an ideal ratio is 0.5 to 2 equivalents of anhydride groups in the tetracarboxylic acid, more preferably 0.8 to 1.2 equivalents, relative to 1 equivalent of the amino groups in the diamine. Similar to conventional polycondensation reactions, the closer the equivalent of the anhydride groups in the tetracarboxylic acid is to 1 equivalent, the larger the molecular weight of the resulting polyamide. The ideal reaction temperature for the production of polyacrylic acid is -20 to 150°C, with 0 to 100°C being even more ideal. Furthermore, the ideal reaction time is 0.1 to 24 hours, with 0.5 to 12 hours being even more ideal. Polyacrylic acid can be produced at any concentration, but the preferred concentration is 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction is initially carried out at a high concentration, and solvent can be added subsequently.

[0051] Specific examples of the aforementioned organic solvents include cyclohexanone, cyclopentanone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and 1,3-dimethyl-2-imidazolidineone. Furthermore, when the polymer has high solvent solubility, solvents such as methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, diethylene glycol monomethyl ether, or diethylene glycol monoethyl ether can be used.

[0052] (Manufacturing of polyamides) Polyamide esters can be obtained by known methods such as [I] reacting polyamide obtained by the above methods with an esterifying agent, [II] reacting tetracarboxylic acid diester with a diamine, and [III] reacting a tetracarboxylic acid diester dihalide with a diamine.

[0053] (Manufacturing of polyimide) Polyimides can be obtained by cyclizing (nitroimizing) polyimide precursors such as polyamides or polyamide esters. Furthermore, the nitroimization rate referred to in this specification is the proportion of nitroimide groups to the total amount of nitroimide groups and carboxyl groups (or their derivatives) derived from tetracarboxylic dianhydrides or their derivatives. The nitroimization rate does not necessarily have to be 100% and can be adjusted arbitrarily according to the application and purpose.

[0054] As a method for amide-imidizing polyimide precursors, thermal amide-imidization can be performed by directly heating a solution of the polyimide precursor, or catalytic amide-imidization can be performed by adding a catalyst to a solution of the polyimide precursor. The temperature at which the polyimide precursor is thermally amided in solution is preferably 100~400℃, more preferably 120~250℃, and it is preferable to remove the generated water outside the system during the amided reaction.

[0055] Catalytic amide formation of polyimide precursors can be achieved by adding an alkaline catalyst and an acid anhydride to a solution of the polyimide precursor, preferably at -20 to 250°C, more preferably at 0 to 180°C with stirring. The amount of alkaline catalyst is preferably 0.5 to 30 moles of the amide group, more preferably 2 to 20 moles, and the amount of acid anhydride is preferably 1 to 50 moles of the amide group, more preferably 3 to 30 moles. Examples of alkaline catalysts include pyridine, triethylamine, trimethylamine, tributylamine, or trioctylamine, among which pyridine is preferred due to its ability to provide adequate alkalinity for the reaction. Examples of acid anhydrides include acetic anhydride, trimellitic anhydride, or phenylmethyltetrahydroquinone anhydride, among which acetic anhydride is preferred because it facilitates purification after the reaction. The amide ratio achieved by catalytic amide imidization can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

[0056] When recovering polyimide precursors or polyimide from a reaction solution of polyimide precursors or polyimide, the reaction solution is simply added to a solvent to precipitate it. Solvents used for precipitation include methanol, ethanol, isopropanol, acetone, hexane, butylceryl ketone, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water. The polymer obtained after precipitation can be recovered by filtration and then dried at room temperature or under normal or reduced pressure. Furthermore, if the recovered polymer is redissolved in an organic solvent and reprecipitated, repeating this operation 2 to 10 times, impurities in the polymer can be reduced. Solvents such as alcohols, ketones, or hydrocarbons are used; ideally, using three or more solvents selected from these sources will result in higher purification efficiency.

[0057] When manufacturing the polyimide precursor and polyimide of this invention, a tetracarboxylic acid component containing tetracarboxylic dianhydride or its derivative, a diamine component containing the aforementioned diamine, and a suitable capping agent can also be used to manufacture a capped polymer. The capped polymer has the effect of increasing the film hardness of the liquid crystal alignment film obtained from the coating and improving the adhesion properties between the sealant and the liquid crystal alignment film. Examples of the polyimide precursors and the ends of the polyimides of this invention include amino groups, carboxyl groups, anhydride groups, or groups derived from the capping agents described below. Amine, carboxyl, and anhydride groups can be obtained through conventional condensation reactions or by sealing the ends using the capping agents described below.

[0058] End-capping agents, such as: acetic anhydride, maleic anhydride, naphthalic anhydride, phthalic anhydride, itaconic anhydride, 1,2-cyclohexanedicarboxylic anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, 3-(3-trimethoxysilyl)propyl)-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, 4-ethynyl phthalic anhydride, etc.; dibutyl dicarbonate, diallyl dicarbonate, etc.; acrylamide chloride, methyl propylene. Chlorocarbonyl compounds such as chlorochloro and nicotinic chlorochloro; monoamine compounds such as aniline, 2-aminophenol, 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine; and isocyanates with unsaturated bonds such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate, or 2-propenyoxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, etc. The preferred ratio of the capping agent to the total 100 moles of diamine used is 0.01 to 20 moles, and even better is 0.01 to 10 moles.

[0059] The weight-average molecular weight (Mw) of the polyimide precursor and polyimide, as determined by gel permeation chromatography (GPC) based on polystyrene, is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. Furthermore, the molecular weight distribution (Mw / Mn), expressed as the ratio of Mw to the number-average molecular weight (Mn) of polystyrene determined by GPC, is preferably 15 or less, more preferably 10 or less. Within this molecular weight range, good alignment of the liquid crystal display element can be ensured.

[0060] The organic solvent contained in the liquid crystal alignment agent of this invention is not particularly limited, as long as it is an organic solvent that can uniformly dissolve the polymer (P) and other polymers added as needed. Examples include: N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactamide, N,N-dimethylpropionic acid, tetramethylurea, N,N-diethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolidinedione, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3 -Methoxy-N,N-dimethylpropionic acid, 3-butoxy-N,N-dimethylpropionic acid, N-(n-propyl)-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(tert-butyl)-2-pyrrolidone, N-(n-pentyl)-2-pyrrolidone, N-(3-methoxypropyl)-2-pyrrolidone, N-(2-ethoxyethyl)-2-pyrrolidone, N-(4-methoxybutyl)-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone (also collectively referred to as good solvents), etc. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropionic acid, 3-butoxy-N,N-dimethylpropionic acid, or γ-butyrolactone are preferred. The content of the good solvent is preferably 20-99% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 20-90% by mass, and particularly ideally 30-80% by mass.

[0061] Furthermore, for the organic solvents contained in the liquid crystal alignment agent, it is preferable to use a mixed solvent that, in addition to the solvents mentioned above, also includes solvents that improve the coatability and surface smoothness of the coating film (also known as undesirable solvents). Specific examples of undesirable solvents are as follows, but are not limited to these. The content of undesirable solvents is ideally 1-80% by mass of the total solvents contained in the liquid crystal alignment agent, 10-80% by mass is better, and 20-70% by mass is especially good. The type and content of undesirable solvents can be appropriately selected according to the coating equipment, coating conditions, coating environment, etc. of the liquid crystal alignment agent.

[0062] Unsuitable solvents include: diisopropyl ether, diisobutyl ether, diisobutylmethanol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propyl carbonate, ethyl carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol, 2-(2-butoxyethoxy) 1-Propanol, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monopropyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol diacetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, cyclohexyl acetate, 4-methyl-2-pentyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, diisobutyl ketone (2,6-dimethyl-4-heptanone), etc.

[0063] Among them, diisobutylmethanol, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, or diisobutyl ketone are preferred.

[0064] Ideal solvent combinations of good and bad solvents include: N-methyl-2-pyrrolidone with ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone with γ-butyrolactone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone with γ-butyrolactone and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone with propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone with propylene glycol diacetate; N,N-dimethyllactamine with diisobutyl ketone; N-methyl-2-pyrrolidone with ethyl 3-ethoxypropionate; N-ethyl-2-pyrrolidone with ethyl 3-ethoxypropionate; N-methyl-2-pyrrolidone with ethyl 3-ethoxypropionate and dipropylene glycol monomethyl ether; N... N-methyl-2-pyrrolidone with ethyl 3-ethoxypropionate and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone with ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether, N-ethyl-2-pyrrolidone with ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether, N-methyl-2-pyrrolidone with ethylene glycol monobutyl ether acetate, N-ethyl-2-pyrrolidone with dipropylene glycol dimethyl ether, N,N-dimethyllactamine with ethylene glycol monobutyl ether, N,N-dimethyllactamine with propylene glycol diacetate, N-ethyl-2-pyrrolidone with diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone with diethylene glycol monoethyl ether and butylceroxose acetate, N-methyl-2-pyrrolidone with diethylene glycol monomethyl ether and butylceroxose acetate, N,N-Dimethyllactic acid with diethylene glycol diethyl ether, N-methyl-2-pyrrolidone with γ-butyrolactone with 4-hydroxy-4-methyl-2-pentanone with diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone with N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone, N-ethyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with propylene glycol monobutyl ether, N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with diisobutyl ketone, N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with dipropylene glycol monomethyl ether, N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with diisobutyl ketone, N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with dipropylene glycol monomethyl ether, N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone N-methyl-2-pyrrolidone with propylene glycol monobutyl ether, N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with propylene glycol diacetate, N-ethyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with dipropylene glycol dimethyl ether, γ-butyrolactone with 4-hydroxy-4-methyl-2-pentanone with diisobutyl ketone, γ-butyrolactone with 4-hydroxy-4-methyl-2-pentanone with propylene glycol diacetate, N-methyl-2-pyrrolidone with γ-butyrolactone with propylene glycol monobutyl ether with diisobutyl ketone, N-methyl-2-pyrrolidone with γ-butyrolactone with propylene glycol monobutyl ether with diisopropyl ether, N-methyl-2-pyrrolidone with γ-butyrolactone with propylene glycol monobutyl ether with diisopropyl ether, N-methyl-2-pyrrolidone with γ-butyrolactone N-methyl-2-pyrrolidone with γ-butyrolactone with propylene glycol monobutyl ether and diisobutylmethanol, N-methyl-2-pyrrolidone with γ-butyrolactone with dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone with propylene glycol monobutyl ether and dipropylene glycol dimethyl ether, N-ethyl-2-pyrrolidone with propylene glycol monobutyl ether and dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone with diethylene glycol diethyl ether and dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone with propylene glycol monobutyl ether and propylene glycol diacetate, N-ethyl-2-pyrrolidone with propylene glycol monobutyl ether and diisobutyl ketone, N-ethyl-2-pyrrolidone with γ-butyrolactone and diisobutyl ketone, N-ethyl-2 - Pyrrolidone with N,N-dimethyllactamine and diisobutyl ketone, N-methyl-2-pyrrolidone with ethylene glycol monobutyl ether and ethylene glycol monobutyl ether acetate, γ-butyrolactone with ethylene glycol monobutyl ether acetate and dipropylene glycol dimethyl ether, N-ethyl-2-pyrrolidone with ethylene glycol monobutyl ether acetate and propylene glycol dimethyl ether, N-methyl-2-pyrrolidone with 4-methyl-2-pentyl acetate and ethylene glycol monobutyl ether, N-ethyl-2-pyrrolidone with cyclohexyl acetate and 4-hydroxy-4-methyl-2-pentanone, cyclohexanone with propylene glycol monomethyl ether, cyclopentanone with propylene glycol monomethyl ether, N-methyl-2-pyrrolidone with cyclohexanone and propylene glycol monomethyl ether, etc.

[0065] (Liquid crystal alignment agent) The liquid crystal alignment agent of the present invention may also contain other components (hereinafter also referred to as additive components) in addition to the above-mentioned polymer (P), other polymers, and organic solvents. These additive components may include, for example, at least one crosslinking compound selected from the group consisting of crosslinking compounds having at least one substituent selected from ethylene oxide, propylene oxide, terminal isocyanate groups, oxazolino groups, cyclic carbonate groups, hydroxyl groups, and alkoxy groups, and crosslinking compounds having polymerizable unsaturated groups; functional silane compounds; metal chelate compounds; curing accelerators; surfactants; antioxidants; sensitizers; preservatives; and compounds used to adjust the dielectric constant and resistance of the obtained liquid crystal alignment film.

[0066] Ideal specific examples of the aforementioned crosslinking compounds 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, glycerol diglycidyl ether, dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetracyclooxypropyl-2,4-hexanediol, and EPIKOTE. Bisphenol A type epoxy resins such as 828 (manufactured by Mitsubishi Chemical Corporation), bisphenol F type epoxy resins such as EPIKOTE807 (manufactured by Mitsubishi Chemical Corporation), hydrogenated bisphenol A type epoxy resins such as YX-8000 (manufactured by Mitsubishi Chemical Corporation), epoxy resins containing biphenyl backbones such as YX6954BH30 (manufactured by Mitsubishi Chemical Corporation), and phenolic varnish type epoxy resins such as EPPN-201 (manufactured by Nippon Kayaku Co., Ltd.) Compounds containing tertiary nitrogen atoms, such as EOCN-102S (manufactured by Nippon Kayaku Co., Ltd.) and others (ortho, meta, para) cresol phenolic varnish epoxy resins; trichloropropylene isocyanate such as TEPIC (manufactured by Nissan Chemical Co., Ltd.); alicyclic epoxy resins such as CELLOXIDE2021P (manufactured by Daicel Co., Ltd.); compounds containing tertiary nitrogen atoms, such as N,N,N',N'-tetracyclooxypropyl-4,4'-diaminodiphenylmethane; compounds containing two or more ethylene oxides, such as tetra(epoxypropoxymethyl)methane; compounds containing two or more propylene oxides as described in paragraphs

[0170] to

[0175] of WO2011 / 132751; CORONATEAP stable Compounds containing terminal isocyanate groups, such as M, CORONATE2503, 2515, 2507, 2513, 2555, MILLIONATEMS-50 (all manufactured by Tosoh Corporation), TAKENATEB-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, and B-882N; Compounds containing an acezoline group, such as 2,2'-bis(2-acezoline), 2,2'-bis(4-methyl-2-acezoline), 2,2'-bis(5-methyl-2-acezoline), 1,2,4-tris(2-acezoline)-benzene, and EPOCROS (manufactured by Nippon Shokubai Co., Ltd.); compounds containing a cyclic carbonate group as described in paragraphs

[0025] to

[0030] and

[0032] of WO2011 / 155577.Compounds containing hydroxyl or alkoxy groups, such as N,N,N',N'-tetra(2-hydroxyethyl)hexamethylenediamine, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethoxyphenyl)propane, and 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)-1,1,1,3,3,3-hexafluoropropane; and compounds represented by glycerol mono(meth)acrylate, glycerol di(meth)acrylate (1,2-,1,3-dimethyl mixture), glycerol tri(meth)acrylate, glycerol 1,3-diglyceric acid di(meth)acrylate, pentaerythritol tri(meth)acrylate, diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, pentaethylene glycol mono(meth)acrylate, and hexaethylene glycol mono(meth)acrylate.

[0067] The compounds used to adjust dielectric constant and resistance include, for example, monoamines containing nitrogen-containing aromatic heterocycles such as 3-pyridinemethylamine. The content of the monoamine containing nitrogen-containing aromatic heterocycles is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the polymer component in the liquid crystal alignment agent, and more preferably 0.1 to 20 parts by mass.

[0068] Ideal specific examples of the aforementioned functional silane compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureopropyltrimethoxysilane, 3-ureopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-epoxypropoxypropylmethyldimethoxysilane. Alkane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-epoxypropoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-propenyloxypropyltrimethoxysilane, tris(3-(trimethoxysilyl)propyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, etc. The content of functional silane compounds is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of polymer components contained in the liquid crystal alignment agent, and more preferably 0.1 to 20 parts by mass.

[0069] The concentration of solid components in the liquid crystal alignment agent (the ratio of the total mass of components other than the solvent in the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) can be appropriately selected by taking into account viscosity, volatility, etc., and is preferably 1 to 10 by mass. The ideal range of solid content concentration depends on the method used to coat the liquid crystal alignment agent onto the substrate. For example, when using spin coating, a solid content concentration of 1.5 to 4.5% by mass is preferred. When using printing, a solid content concentration of 3 to 9% by mass is preferable, thereby achieving a solution viscosity of 12 to 50 mPa·s. When using inkjet printing, a solid content concentration of 1 to 5% by mass is preferable, thereby achieving a solution viscosity of 3 to 15 mPa·s. The preferred temperature for preparing the polymer composition is 10 to 50°C, more preferably 20 to 30°C.

[0070] (Liquid crystal alignment film and liquid crystal display element) The liquid crystal display element of the present invention includes a liquid crystal alignment film formed using the aforementioned liquid crystal alignment agent. The operating mode of the liquid crystal display element is not particularly limited, and it can employ various operating modes such as TN mode, STN mode, vertical alignment mode (including VA-MVA mode, VA-PVA mode, etc.), in-plane switching mode (IPS mode, FFS mode), and optically compensated bending mode (OCB mode).

[0071] The liquid crystal display element of the present invention can be manufactured by, for example, a method including the following steps (1) to (4), a method including steps (1) to (2) and (4), a method including steps (1) to (3), (4-2) and (4-4), or a method including steps (1) to (3), (4-3) and (4-4).

[0072] <Step (1): The step of coating the liquid crystal alignment agent on the substrate> Step (1) is the step of coating the liquid crystal alignment agent of the present invention onto the substrate. A specific example of step (1) is as follows. On one side of a substrate having a patterned transparent conductive film, the liquid crystal alignment agent of the present invention is applied using a suitable coating method such as roll coating, spin coating, printing, or inkjet coating. Here, the substrate is not particularly limited to any substrate with high transparency; glass substrates, silicon nitride substrates, acrylic substrates, polycarbonate substrates, and other plastic substrates can also be used. Furthermore, for reflective liquid crystal display elements, if only a single-sided substrate is used, opaque materials such as silicon wafers can be used; in this case, the electrodes can also be made of light-reflecting materials such as aluminum. Moreover, when manufacturing IPS or FFS type liquid crystal display elements, a substrate having electrodes composed of a patterned comb-shaped transparent conductive film or metal film is used, along with a facing substrate without electrodes. An IPS substrate is a comb-shaped electrode substrate used in IPS-type liquid crystal display elements. For example, it has a substrate, a plurality of linear electrodes formed and arranged in a comb shape on the substrate, and a liquid crystal alignment film formed on the substrate in such a way as to cover the linear electrodes. Furthermore, the FFS substrate used in the comb electrode substrate of the FFS liquid crystal display element may, for example, have a substrate, a surface electrode formed on the substrate, an insulating film formed on the surface electrode, a plurality of linear electrodes formed on the insulating film and arranged in a comb shape, and a liquid crystal alignment film formed on the insulating film in such a way as to cover the linear electrodes.

[0073] Methods for coating liquid crystal alignment agents onto a substrate and forming a film include screen printing, offset printing, flexographic printing, inkjet printing, and spraying. Among these, inkjet printing is an ideal coating and film-forming method.

[0074] <Step (2): Calcination of the coated liquid crystal alignment agent> Step (2) is the step of calcining the liquid crystal alignment agent that has been coated on the substrate to form a film. A specific example of step (2) is as follows. After coating the liquid crystal alignment agent onto the substrate in step (1), a heating method such as a hot plate, a thermally circulating oven, or an IR (infrared) oven can be used to evaporate the solvent or to thermally amide polyamide or polyamide ester. The drying and calcination steps after coating the liquid crystal alignment agent of this invention can be performed at any temperature and for any time, and can be repeated multiple times. For example, the calcination temperature of the liquid crystal alignment agent can be 40-180°C. From the viewpoint of reducing processing time, it can be performed at 40-150°C. The calcination time is not particularly limited, and can be 1-10 minutes or 1-5 minutes. When performing thermal amide amide as a representative polyamide precursor, a calcination step at a temperature range of, for example, 150-300°C or 150-250°C can be added after the above steps. The calcination time is not specifically limited; examples include calcination times of 5-40 minutes or 5-30 minutes. If the film after calcination is too thin, the reliability of the liquid crystal display element will be reduced. Therefore, 5~300nm is more ideal, and 10~200nm is even more ideal.

[0075] <Step (3): The step of performing alignment treatment on the membrane obtained in step (2)> Step (3) involves performing alignment treatment on the film obtained in step (2), depending on the circumstances. That is, for horizontally aligned liquid crystal display elements such as IPS or FFS types, the coating is subjected to alignment capability treatment. On the other hand, for vertically aligned liquid crystal display elements such as VA or PSA (Polymer Sustained Alignment) types, the formed coating can be directly used as a liquid crystal alignment film, but alignment capability treatment can also be performed on the coating. Alignment treatment methods for liquid crystal alignment films include rubbing treatment and photoalignment treatment. For photoalignment treatment, a method is to irradiate the surface of the film with radiation deflected in a certain direction, and, depending on the circumstances, heat it at a temperature of 150~250°C to impart liquid crystal alignment properties (also called liquid crystal alignment capability). The radiation can be ultraviolet light or visible light with a wavelength of 100~800nm. Among them, ultraviolet light with a wavelength of 100~400nm is preferred, and more preferably 200~400nm is preferred.

[0076] The ideal radiation dose is 1 to 10,000 mJ / cm², with 100 to 5,000 mJ / cm² being even more ideal. Furthermore, to improve liquid crystal alignment, the substrate with the aforementioned film can be heated to 50 to 250°C while being irradiated with radiation. The liquid crystal alignment film prepared in this manner enables the liquid crystal molecules to be stably aligned in a specific direction.

[0077] Alternatively, for coatings irradiated with polarized radiation as described above, or coatings that have undergone friction alignment treatment, contact treatment can be performed using water or a solvent. Alternatively, films that have undergone the above alignment treatment can be subjected to heat treatment without contact treatment. Furthermore, films that have undergone the above contact treatment can be further subjected to heat treatment.

[0078] The solvents used in the above-mentioned contact treatment can be any solvent that can dissolve the decomposition products generated from the film due to radiation irradiation; there are no special restrictions. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl ceroxysulfate, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate, etc. The solvent can be one or a combination of two or more.

[0079] The preferred temperature for heat treatment of the above-mentioned radiation-exposed coatings is 50~300℃, and even more preferably 120~250℃. The preferred heat treatment time is 1~30 minutes.

[0080] <Step (4): Steps for fabricating liquid crystal cells> Prepare two substrates with liquid crystal alignment films formed as described above, and place liquid crystal between the two opposing substrates. Specifically, the following two methods can be listed. The first method involves aligning two substrates with their respective liquid crystal alignment films facing each other, separated by a cell gap. Then, the two substrates are bonded together at their peripheries using a sealant, and liquid crystal composition is injected into the cell gaps separated by the substrate surface and the sealant. After the composition contacts the film surface, the injection holes are sealed. There are no special restrictions on the liquid crystal composition mentioned above; various liquid crystal compositions containing at least one liquid crystal compound (liquid crystal molecule) and having positive or negative dielectric anisotropy can be used. Furthermore, liquid crystal compositions with positive dielectric anisotropy will be referred to as positive liquid crystals, and liquid crystal compositions with negative dielectric anisotropy will be referred to as negative liquid crystals. The aforementioned liquid crystal composition may also contain liquid crystal compounds having fluorine atoms, hydroxyl groups, amino groups, fluorine-containing groups (e.g., trifluoromethyl), cyano groups, alkyl groups, alkoxy groups, alkenyl groups, isothiocyanate groups, heterocyclic groups, cycloalkanes, cycloalkenes, steroid skeletons, benzene rings, or naphthyl rings. It may also contain compounds with two or more rigid sites (liquid crystal proto-skeletons) exhibiting liquid crystal properties within the molecule (e.g., rigid biphenyl structures, or biphenyl structures linked by alkyl groups forming a double liquid crystal proto-skeleton). The liquid crystal composition may also be a nematic phase liquid crystal composition, a lamellar phase liquid crystal composition, or a cholesterol phase liquid crystal composition. Furthermore, in view of improving the alignment properties of the liquid crystal, additives can be added to the aforementioned liquid crystal composition. Such additives include photopolymerizable monomers such as compounds with polymerizable groups (such as methacrylic acid groups); optically active compounds (e.g., S-811 manufactured by Merck); antioxidants; ultraviolet absorbers; pigments; defoamers; polymerization initiators or polymerization inhibitors, etc. Positive LCDs include those manufactured by Merck such as ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, and MLC-7081. Negative liquid crystal displays include those manufactured by Merck, such as MLC-3023, MLC-6608, MLC-6609, MLC-6610, MLC-6882, MLC-6886, MLC-7026, MLC-7026-000, MLC-7026-100, and MLC-7029. Furthermore, in the PSA mode, an example of a liquid crystal containing a compound with polymerizable groups is MLC-3023 manufactured by Merck.

[0081] The second method is called the ODF (One Drop Fill) method. On one of the two substrates with a pre-formed liquid crystal alignment film, a UV-curable sealant is applied to a predetermined location. Then, liquid crystal composition is dropped onto predetermined locations on the liquid crystal alignment film surface. Next, the other substrate is bonded with the liquid crystal alignment films facing each other, pressing the liquid crystal composition onto the entire surface of the substrate so that it contacts the film surface. Then, the entire surface of the substrate is irradiated with UV light to harden the sealant. When using either method, it is advisable to further heat until the liquid crystal composition reaches a temperature suitable for isotropic phase, and then slowly cool it to room temperature to remove the flow alignment during liquid crystal filling. Furthermore, when the coating is subjected to friction treatment, the two substrates are arranged facing each other at a predetermined angle, such as orthogonal or antiparallel, with the friction directions of each coating film being opposite each other. For sealants, epoxy resins containing alumina spheres can be used as hardeners and spacers. For liquid crystals, nematic liquid crystals and smectic liquid crystals are examples, with nematic liquid crystals being preferred.

[0082] The liquid crystal alignment agent of the present invention is also suitable for use in liquid crystal display elements (PSA type liquid crystal display elements) that have a liquid crystal layer between a pair of substrates having electrodes, and a liquid crystal composition containing a polymerizable compound that is polymerized by at least one of active energy rays and heat disposed between the pair of substrates, and that polymerizable compound is polymerized by applying voltage between the electrodes and by irradiation with active energy rays and heating. Furthermore, the liquid crystal alignment agent of the present invention is also suitable for use in liquid crystal display elements (SC-PVA type liquid crystal display elements) manufactured by applying a voltage between electrodes, wherein a liquid crystal layer is provided between a pair of substrates having an electrode, and a liquid crystal alignment film containing polymerizable groups that are polymerized by at least one of active energy rays and heat is disposed between the pair of substrates.

[0083] <Step (4-2): Case of PSA liquid crystal display element> Except for injecting or dropping the liquid crystal composition containing the polymeric compound, the process is the same as described in (4) above. Examples of polymeric compounds include polymeric compounds having one or more polymeric unsaturated groups such as acrylate groups or methacrylate groups within their molecules.

[0084] Step (4-3): The situation of liquid crystal display element of SC-PVA method Alternatively, after proceeding in the same manner as described in (4) above, a method for manufacturing liquid crystal display elements by irradiating with ultraviolet light as described later can be adopted. If this method is followed, a liquid crystal display element with excellent response speed with low light irradiation can be obtained, similar to the liquid crystal display element manufactured in the PSA manner described above. The compound having a polymerizable group can be a compound having one or more of the above-mentioned polymerizable unsaturated groups in the molecule, and its content is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the total polymer component, more preferably 1 to 20 parts by mass. Furthermore, the polymer used as a liquid crystal alignment agent can have the above-mentioned polymerizable group. Such a polymer can be exemplified by, for example, a polymer obtained by using a diamine component containing a diamine terminally having the above-mentioned photopolymerizable group in the reaction.

[0085] Step (4-4): Steps for irradiating with ultraviolet light The liquid crystal cells are irradiated with a voltage applied between the conductive films on the substrate as obtained in either (4-2) or (4-3) above. The applied voltage can be, for example, DC or AC of 5-50V. The irradiated light can be ultraviolet light or visible light containing wavelengths of, for example, 150-800nm, but ultraviolet light containing wavelengths of 300-400nm is preferred. The light source can be, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonant lamp, a xenon lamp, or an excimer laser. The irradiation intensity is preferably 1,000-200,000 J / m², more preferably 1,000-100,000 J / m².

[0086] Furthermore, a polarizing plate can be attached to the outer surface of the liquid crystal cell as needed to obtain a liquid crystal display element. Examples of polarizing plates attached to the outer surface of the liquid crystal cell include: a polarizing film called an "H film" that has polyvinyl alcohol extended and aligned on one side and absorbs iodine on the other side, which is sandwiched with a cellulose acetate protective film to obtain a polarizing plate, or a polarizing plate composed of the H film itself. [Example]

[0087] The following examples illustrate the invention in more detail, but the invention is not limited to these examples. Furthermore, the methods for determining the properties of the compounds are shown below.

[0088] (Organic solvents) NMP: N-methyl-2-pyrrolidone GBL: γ-Butyrolactone BCS: Butylcerox (ethylene glycol monobutyl ether) THF: Tetrahydrofuran DMF: N,N-Dimethylformamide

[0089] (Diamine) DA-1 to DA-10: Each is a compound represented by the formula (DA-1) to (DA-10). Also, DA-2 to DA-4 represent mixtures containing multiple compounds with n being any integer from 6 to 16. The diamines belonging to the specific diamines of this invention are compounds represented by the formula (DA-1) to (DA-4). [Chemistry 9]

[0090] (Tetracarboxylic acid derivative) CA-1~CA-4: Each is a compound represented by the formula (CA-1)~(CA-4). [Chemistry 10]

[0091] (additive) AD-1~AD-2: Each is a compound represented by the formula (AD-1)~(AD-2). [Chemistry 11]

[0092] <Viscosity> In the synthesis example, the viscosity of the polymer solution was measured using a TVE-22H E-type viscometer (manufactured by Toki Sangyo Co., Ltd.) with a sample volume of 1.1 mL, a conical rotor TE-1 (1°34', R24), and a temperature of 25°C.

[0093] [Synthesis of Monomers] DA-1 was synthesized according to the method described in Chemical Communications (2016), 52(45), 7310-7313. DA-2 to DA-4 are novel compounds not disclosed in the literature, and their synthesis methods are described in detail below. The products described in the following monomer synthesis examples were identified by 1H-NMR analysis (analytical conditions are as follows). Apparatus: Fourier transform superconducting nuclear magnetic resonance (FT-NMR) device "AVANCE III" (BRUKER) 500MHz. Solvent: Deuterated dimethyl sulfoxide (DMSO-d6); Standard substance: Tetramethylsilane

[0094] (Single Synthesis Example 1: Synthesis of DA-2) [Chemistry 12] 4-Nitrophenyl isocyanate (5.00 g, 30.5 mmol) and DMF (40 g) were added to a flask, cooled to 0°C, and stirred. After stirring for 30 minutes, a solution of PEG600 (Tokyo Chemical Industries, Ltd., 8.71 g, 14.5 mmol) dissolved in DMF (15 g) was slowly added dropwise to the flask using a dropping funnel while stirring. After the addition was complete, the mixture was stirred at room temperature (25°C) to allow the reaction to proceed. Once the reaction was confirmed to be complete, the reaction solution was transferred to a separatory funnel, and ethyl acetate (300 g) and pure water (100 g) were added, followed by separation. The organic layer was separated and washed with pure water. The organic layer was dried over magnesium sulfate and filtered, and the solvent was removed by distillation to obtain DA-2-1 (yield 10.2 g, 11.0 mmol, 76%). The 1H-NMR results shown below confirmed that it was DA-2-1. Furthermore, the protons in the 3.66-3.33 ppm range originate from the repeating unit "**-O-[CH 2-CH 2-O] n-** (** represents the atomic bond with the carbon atom of the methylene group. n is an integer representing the repeating unit.)" or from the β-methylene hydrogen of the carbamate bond, and there are protons with an integral value of approximately 50. 1H-NMR (500MHz), in DMSO-d 6: δ (ppm) = 10.52 (s, 2H), 8.20 (d, 4H), 7.70 (d, 4H), 4.26 (t, 4H), 3.66-3.33 (m)

[0095] [Chemistry 13] DA-2-1 (10.2 g, 11.0 mmol) and THF (40 g) were added to a flask and dissolved. Then, 1.0 g of carbon-supported palladium (5% Pd carbon powder (50% aqueous content), K type, manufactured by NE Chemcat) was added for hydrogen substitution. The mixture was stirred at room temperature (25 °C) to allow the reaction to proceed. After the reaction was complete, the carbon-supported palladium was removed using a membrane filter, and the THF was distilled off to obtain DA-2 (yield 7.90 g, 9.1 mmol, 83%). The 1H-NMR results shown below confirmed that this viscous substance was DA-2. Furthermore, the protons in the 3.61-3.32 ppm range originate from the repeating unit "**-O-[CH 2-CH 2-O] n-** (** represents the atomic bond with the carbon atom from the methylene group. n is an integer representing the repeating unit.)" or from the β-methylene hydrogen atom of the carbamate bond, and there are protons with an integral value of approximately 50. 1H-NMR (500MHz), in DMSO-d 6: δ (ppm) = 9.19 (s, 2H), 7.07 (d, 4H), 6.47 (m, 4H), 4.76 (s, 4H), 4.13 (t, 4H), 3.61-3.32 (m)

[0096] (Single Synthesis Example 2; Synthesis of DA-3) [Chemistry 14] Add PEG600 (manufactured by Tokyo Chemical Industry Co., Ltd., 6.0 g, 10 mmol) and THF (108 g) to a flask and dissolve them. Cool to 0°C and while stirring, gradually add small amounts of sodium hydride (60%, dispersed in flowing paraffin, 1.0 g, 25 mmol). After stirring for 15 minutes, slowly add a solution of 4-fluoronitrobenzene (2.8 g, 20 mmol) dissolved in THF (12 g) to the flask using a dropping funnel. After the addition is complete, stir at room temperature (25°C) to allow the reaction to proceed. Once the reaction is confirmed to be complete, cool the reaction vessel in a water bath and carefully foam while gradually adding small amounts of methanol (12 g) to deactivate any unreacted sodium hydride. Add ethyl acetate (240 g) and pure water (60 g) and separate the layers. Separate the organic layer and wash it in the following order: pure water (60 g) and 5% sodium bicarbonate solution (60 g). The organic layer was dried with magnesium sulfate and filtered, followed by solvent distillation to obtain DA-3-1 (yield 7.8 g, 9.2 mmol, 92% yield). The 1H-NMR results shown below confirmed it to be DA-3-1. Furthermore, the protons in the 3.60–3.49 ppm range originated from the repeating unit "**-O-[CH₂-CH₂-O]n-**" (** represents the atomic bond to the carbon atom of the methylene group. n is an integer representing the repeating unit.)", with an integral value of approximately 44 protons present. 1H-NMR(500MHz), in DMSO-d 6:8.20(d,4H),7.16(d,4H),4.25(t,4H),3.78(t,4H),3.60-3.49(m)

[0097] [Chemistry 15] DA-3-1 (7.8 g, 9.2 mmol) was dissolved in methanol (157 g) in a flask. Then, 0.83 g of carbon-supported palladium (5% Pd carbon powder (50% aqueous) K type, NE Chemcat) was added for hydrogen substitution. The mixture was stirred at room temperature to allow the reaction to proceed. After the reaction was complete, the carbon-supported palladium was removed using a membrane filter, and the methanol was distilled off to obtain DA-3 (yield 7.2 g, 9.2 mmol, 100%). The 1H-NMR results shown below confirmed that this solid was DA-3. Furthermore, the protons in the 3.67-3.16 ppm range originated from the repeating unit "**-O-[CH₂-CH₂-O]n-**" (** represents the atomic bond with the carbon atom from the methylene group. n is an integer representing the repeating unit) or from the β-methylene hydrogen of the aromatic ether, with an integral value of approximately 48 protons present. 1H-NMR(500MHz) in DMSO-d 6:δ(ppm)=6.63(d,4H),6.48(d,4H),4.58(s,4H),3.91(t,4H),3.67-3.16(m)

[0098] (Single Synthesis Example 3; Synthesis of DA-4) [Chemistry 16] PEG600 (Tokyo Chemical Industries, Ltd., 12.0 g, 20 mmol) and THF (180 g) were added to a flask and dissolved. Triethylamine (5.0 g, 50 mmol) was then added, and the mixture was cooled to 0°C. While stirring, 4-nitrobenzyl chloride (7.6 g, 41 mmol) was added gradually in small amounts. After the addition was complete, the mixture was stirred at room temperature (25°C) to allow the reaction to proceed. After the reaction was complete, ethyl acetate (600 g) and pure water (240 g) were added, and the mixture was separated. The organic layer was separated and washed with pure water (240 g). The organic layer was dried over magnesium sulfate, filtered, and the solvent was removed by distillation to obtain DA-4-1 (yield 15.9 g, 17.7 mmol, 88%). The 1H-NMR results shown below confirmed that it was DA-4-1. Furthermore, the protons in the 3.79-3.31 ppm range originate from the repeating unit "**-O-[CH 2-CH 2-O] n-** (** represents the atomic bond with the carbon atom from the methylene group. n is an integer representing the repeating unit.)" or from the protons of the β-methylene hydrogen in the ester, and there are protons with an integral value of approximately 44. 1H-NMR(500MHz), in DMSO-d 6:8.35(d,4H),8.18(d,4H)4.45(t,4H),3.79-3.31(m)

[0099] [Chemistry 17] DA-4-1 (15.9 g, 17.7 mmol) was dissolved in methanol (248 g), and 1.59 g of carbon-supported palladium (5% Pd carbon powder (50% aqueous content), K type, NE Chemcat) was added for hydrogen substitution. The reaction was then stirred at room temperature (25 °C) to allow it to react. After the reaction was complete, the carbon-supported palladium was removed using a membrane filter, and the methanol was distilled off to obtain DA-4 (yield 14.46 g, 17.2 mmol, 97% yield). The 1H-NMR results shown below confirmed that this solid was DA-4. Furthermore, the protons in the range of 3.70–3.49 ppm originated from the repeating unit "**-O-[CH 2-CH 2-O] n-** (** represents the atomic bond with the carbon atom from the methylene group. n is an integer representing the repeating unit.)" or from the protons of the β-methylene hydrogen at the ester, with an integral value of approximately 48. 1H-NMR (500MHz), in DMSO-d 6: δ (ppm) = 7.65-7.63 (m, 4H), 6.57-6.55 (m, 4H), 5.95 (s, 4H) 4.27 (t, 4H), 3.70-3.49 (m)

[0100] [Polymer Synthesis] (Synthesis example 1) DA-1 (1.34 g, 2.88 mmol), DA-5 (2.61 g, 9.12 mmol), and NMP (29.0 g) were measured into a 100 mL flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred while supplying nitrogen to dissolve the diamine solution. CA-1 (2.26 g, 11.5 mmol) and NMP (16.6 g) were then added to this diamine solution while stirring under water cooling. The mixture was stirred for 4 hours under nitrogen to obtain a polyacrylic acid solution (PAA-1) (viscosity: 240 mPa·s).

[0101] (Synthesis Examples 2~16) Using the diamines and tetracarboxylic acid derivatives shown in Table 1 below, the same procedure as in Synthesis Example 1 was performed to obtain solutions of polyamides (PAA-2) to (PAA-16) shown in Table 1 below. In Table 1, the numerical values ​​marked under the compound names represent the mass of each compound used in the synthesis.

[0102] [Table 1]

[0103] [Preparation of Liquid Crystal Alignment Agents] (Example 1) The polyacrylic acid solution (PAA-1) (5.83 g) obtained in Synthesis Example 1 was measured into a 50 mL Erlenmeyer flask equipped with a stir bar, and NMP (0.52 g), GBL (9.30 g), BCS (4.00 g), and NMP solution containing 10% by mass of AD-1 (0.35 g) were added. The mixture was stirred at room temperature for 2 hours to obtain the liquid crystal alignment agent (1).

[0104] (Examples 2-12, Comparative Examples 1-6) The polyamide solution, solvent, and additives used were changed as shown in Table 2 below. Otherwise, the same operation as in Example 1 was performed to obtain liquid crystal alignment agents (2) to (18). Also, additives AD-1 and AD-2 in Table 2 were each added in the form of a solution containing 10% by mass of NMP.

[0105] [Table 2]

[0106] [Fabrication of FFS-driven liquid crystal cells] A liquid crystal cell comprising a liquid crystal display element having a fringe field switching (FFS) mode. First, prepare the substrate for the electrodes. The substrate is a 30mm × 35mm glass substrate with a thickness of 0.7mm. An ITO electrode (thickness: 50nm, electrode width: 20mm vertically, 10mm horizontally) with a full-surface pattern, constituting the first opposing electrode, is formed on the substrate. A SiN (silicon nitride) film, formed using CVD (chemical vapor deposition), is formed on top of the first opposing electrode. The second SiN film has a thickness of 300nm and acts as an interlayer insulating film. On top of the second SiN film, a comb-shaped pixel electrode (thickness: 50nm) formed by patterning the ITO film is disposed as the third layer, forming two pixels, the first and second pixels, each approximately 10mm vertically and 5mm horizontally. At this point, the first opposing electrode and the third pixel electrode are electrically insulated by the second SiN film. The third layer of pixel electrodes has a central portion with multiple arranged comb-like teeth, with 3μm wide electrode elements that are bent at an inner angle of 160° and spaced 6μm apart. Each pixel is divided into a first zone and a second zone by the line connecting the bent portions of multiple electrode elements. Comparing the first and second regions of each pixel, the electrode elements constituting them are formed in different directions. Specifically, when the direction of the bend connecting the multiple electrode elements is used as a reference, the first region of the pixel is formed with the electrode elements of the pixel electrode at an 80° clockwise angle, while the second region of the pixel is formed with the electrode elements of the pixel electrode at an 80° counterclockwise angle. In other words, in the first and second regions of each pixel, the direction of the rotational movement (in-plane switching) of the liquid crystal within the substrate surface caused by the voltage applied between the pixel electrode and the opposing electrode is formed in opposite directions. The obtained liquid crystal alignment agent was then filtered through a 1.0 μm pore size filter and spin-coated onto the surface of the prepared electrode substrate (first glass substrate) and the surface of the glass substrate with a 4 μm high columnar spacer on the back side where an ITO film has been formed. After drying on a hot plate at 80°C for 5 minutes, it was calcined in a hot air circulating oven at 230°C for 20 minutes to obtain a 100 nm thick polyimide film. This polyimide film was then rubbed with a silk cloth (YA-20R manufactured by Yoshikawa Chemical Co., Ltd.) (roller diameter: 120 mm, roller speed: 500 rpm, moving speed: 30 mm / sec, push-in length: 0.3 mm, rubbing direction: 180° relative to the direction of the bends of the multiple electrode elements connecting the third layer pixel electrode), ultrasonically irradiated in pure water for 1 minute, and washed. Water droplets were removed by blowing air. Then, the substrate was dried at 80°C for 15 minutes to obtain a substrate with a liquid crystal alignment film. Two substrates with liquid crystal alignment films were grouped together, and a sealant (Mitsui Chemicals XN-1500T) was printed on the substrates to retain the liquid crystal injection port. Another substrate was then bonded together with the liquid crystal alignment film surfaces facing each other and the friction direction antiparallel. The substrates were then heat-treated at 120°C for 90 minutes to harden the sealant, creating empty cells with a 4μm intercellular gap. These empty cells were then injected with negative liquid crystal MLC-7026 (Merck) using a reduced-pressure injection method, and the injection port was sealed to obtain an FFS-type liquid crystal cell. The obtained liquid crystal cell was then heated at 120°C for 1 hour and placed at 23°C overnight for evaluation.

[0107] [Assessment of alignment stability driven by long-term communication] This evaluation assesses the image retention (also known as AC image retention) caused by the deterioration of the alignment performance of the liquid crystal alignment film under long-term AC driving. Using the FFS liquid crystal cell fabricated above, an AC voltage of ±12V at a frequency of 30Hz was applied for 120 hours under a high-brightness backlight (luminance: 20000 cd / m²) with a surface temperature of 50°C. Afterwards, the pixel electrode and the opposing electrode of the liquid crystal cell were short-circuited, and the cell was left at room temperature for one day. Following this, the liquid crystal cell was placed between two polarizing plates configured with their polarization axes orthogonal. The backlight was then turned on without any applied voltage. The arrangement angle of the liquid crystal cell was adjusted to minimize the transmitted light intensity of region 1 of the first pixel. The rotation angle required to minimize the transmitted light intensity of region 2 of the first pixel was calculated and recorded as angle Δ. The same angle Δ was calculated for region 2 of the second pixel, comparing it to region 1. The average angle Δθ of the first and second pixels was then calculated as the rotation angle Δθ of the liquid crystal cell. Regarding the stability of liquid crystal alignment, a smaller value of the rotation angle Δθ is considered better. As an evaluation criterion, a rotation angle Δθ of less than 0.2 degrees is rated as "good," and a value greater than 0.20 degrees is rated as "poor."

[0108] [The mitigating properties of stored charge] The aforementioned FFS liquid crystal cell was placed between two polarizing plates arranged orthogonally to the polarizing axes. With the pixel electrode and the opposing electrode short-circuited and at the same potential, LED backlight was pre-illuminated from below the two polarizing plates. The angle of the liquid crystal cell was adjusted to minimize the brightness of the LED backlight transmitted light measured above the two polarizing plates. Then, while applying an AC voltage of 30 Hz to the liquid crystal cell, the VT curve (voltage-transmittance curve) was measured, and the AC voltage at which the relative transmittance reached 23% was defined as the driving voltage. Subsequently, while applying a rectangular wave of 30 Hz to the liquid crystal cell, the VT characteristics (voltage-transmittance characteristics) at a temperature of 23°C were measured, and the AC voltage at which the relative transmittance reached 23% was calculated. This AC voltage corresponds to the region where brightness varies greatly with voltage, and is therefore suitable for evaluating the stored charge through brightness. Then, an AC voltage of 60 Hz with a relative transmittance of 23% was applied to drive the liquid crystal cells while simultaneously applying a DC voltage of +1.0V for 30 minutes. After that, the application of the DC voltage was stopped, and the cells were driven again with only the AC voltage for 15 minutes. The faster the accumulated charge is neutralized, the faster the charge accumulates in the liquid crystal cells when the DC voltage is applied. Therefore, the neutralization characteristics of the accumulated charge are evaluated by measuring the change in relative transmittance immediately after the DC voltage is applied. The shorter this time, the better the neutralization characteristics of the accumulated charge. Starting from the moment the DC voltage is applied, if the relative transmittance drops below 28% within 10 minutes, it is rated as "◎"; if it exceeds 10 minutes but is within 20 minutes, it is rated as "○"; if it exceeds 20 minutes but is within 30 minutes, it is rated as "△"; if the relative transmittance does not drop below 28% within 30 minutes, it is rated as "×". Furthermore, the image retention evaluation according to the above method is performed under the temperature condition that the liquid crystal cell temperature is 40°C.

[0109] Fabrication of liquid crystal cells for voltage retention evaluation First, prepare the substrate with the electrodes. The substrate is a glass substrate with a size of 30mm × 40mm and a thickness of 1.1mm. Use ITO electrodes with a film thickness of 35nm that have been formed on the substrate, and the electrodes are in a stripe pattern with a spacing of 40mm vertically and 10mm horizontally. The obtained liquid crystal alignment agent was then filtered through a 1.0 μm pore size filter and spin-coated onto the prepared electrode substrate. After drying on a hot plate at 80°C for 2 minutes, it was calcined in an infrared furnace at 230°C for 20 minutes to form a 100 nm thick coating, obtaining a substrate with a liquid crystal alignment film. This liquid crystal alignment film was then subjected to friction alignment treatment using a spinning cloth (Yoshikawa Chemical, YA-20R) (roller diameter: 120 mm, roller speed: 1000 rpm, moving speed: 20 mm / sec, push-in length: 0.4 mm), followed by ultrasonic irradiation in pure water for 1 minute for cleaning. After removing water droplets by blowing air, it was dried at 80°C for 10 minutes to obtain the substrate with the liquid crystal alignment film. Two substrates with attached liquid crystal alignment films were prepared. On one substrate, spherical spacers with a particle size of 4 μm were dispersed on the surface of the liquid crystal alignment film. The liquid crystal injection port was left open, and a sealant (Mitsui Chemicals XN-1500T) was printed around it. The other substrate was then bonded together, with the friction directions opposite and the film surfaces facing each other. The substrate was then heat-treated at 120°C for 90 minutes to harden the sealant, creating a void cell. This void cell was then injected with negative liquid crystal MLC-7026 (Merck) using a depressurized injection method, and the injection port was sealed to obtain a liquid crystal cell. The obtained liquid crystal cell was then heated at 120°C for 1 hour and placed at 23°C overnight for various evaluations.

[0110] [Evaluation of Voltage Holding Rate] For the liquid crystal cells used to evaluate voltage retention rate as described above, a voltage of 1V is applied at 60°C for 60μsec, and the voltage is measured after 166.7ms. The voltage retained is calculated and defined as the voltage retention rate. A higher voltage retention rate is better. Furthermore, if the voltage retention rate, one of the electrical characteristics of liquid crystal display elements, increases, it indicates that burn-in, one of the display defects of liquid crystal display elements, becomes less likely to occur.

[0111] The evaluation results of the image retention characteristics, charge accumulation mitigation characteristics, and voltage retention rate of liquid crystal display elements using the liquid crystal alignment agents described above are shown in Table 3 below.

[0112] [Table 3]

[0113] By using the liquid crystal alignment agent of the embodiments of the present invention, a liquid crystal alignment film and a liquid crystal display element with good liquid crystal alignment (i.e., excellent AC retention characteristics) and excellent voltage retention rate were obtained. Furthermore, it is understood that the liquid crystal alignment agent of the embodiments of the present invention can obtain a liquid crystal alignment film and a liquid crystal display element with a fast charge accumulation rate. [Industrial Utilization]

[0114] The liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention can be widely used in liquid crystal display elements of various operating modes, and can also be used as, for example, liquid crystal alignment films for phase difference films, liquid crystal alignment films for scanning antennas, liquid crystal array antennas, or liquid crystal alignment films for transmission and scattering type liquid crystal dimming elements.

[0115] The liquid crystal display element of this invention can be effectively applied to devices with various functions, such as LCD TVs, clocks, portable games, word processors, laptops, navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various screens, information displays, etc.

[0116] Furthermore, the entire contents of the specification, scope of application and abstract of Japanese Patent Application No. 2021-177003, filed on October 28, 2021, are hereby cited and incorporated as disclosures of this invention.

Claims

1. A liquid crystal alignment agent, characterized in that it contains a polymer (P), the polymer (P) being selected from at least one of the group consisting of a polyimide precursor obtained using a diamine component containing a diamine represented by the following formula (Da) and a polyimide of the polyimide precursor, wherein in the case where L in the following formula (Da) represents a single bond, -C(=O)- or -OC(=O)-, the diamine component contains two or more diamines represented by the following formula (Da), excluding diamines represented by the following formula (1), wherein L represents a single bond, -C(=O)-, -OC(=O)-, or -NR1-C(=O)-, wherein, R1 represents a hydrogen atom or a methyl group, R represents a hydrogen atom or a methyl group, n is an integer from 6 to 20, and the hydrogen atom on the benzene ring can also be replaced by a monovalent group. In formula (1), R is hydrogen, -OH, alkyl with 1 to 6 carbons, or alkoxy with 1 to 6 carbons, and X1 and X2 are each independently a divalent organic group having alkyl and / or phenyl groups with 1 to 8 carbons.

2. The liquid crystal alignment agent as claimed in claim 1, wherein, In this formula (Da), L represents -NR1-C(=O)-, and R1 represents a hydrogen atom or a methyl group, and the formula contains two or more diamines represented by this formula (Da).

3. The liquid crystal alignment agent as requested in item 1 or 2, wherein, The diamine component also contains other diamines besides the diamine represented by formula (Da).

4. The liquid crystal alignment agent as requested in item 1 or 2, wherein, In formula (Da), the two amine groups are in the para position relative to the divalent organic group linking the benzene ring.

5. The liquid crystal alignment agent as requested in item 1 or 2, wherein, The diamine represented by formula (Da) is any diamine selected from the group consisting of formulas (da-1) to (da-3), where n is an integer from 6 to 20, and the hydrogen atom on the benzene ring can also be replaced by a monovalent group.

6. The liquid crystal alignment agent as requested in item 1 or 2, wherein, The polymer (P) is obtained by polycondensation of the diamine component with a tetracarboxylic acid component containing at least one compound selected from the group consisting of acyclic aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride, or derivatives thereof.

7. The liquid crystal alignment agent as requested in item 1 or 2, wherein, The formula (Da) indicates that the amount of diamine used is 1 mol% or more relative to the diamine component.

8. The liquid crystal alignment agent of claim 1 or 2 further comprises a polymer (B), which is selected from at least one of the group consisting of a polyimide precursor obtained by using a diamine component that does not contain the diamine represented by formula (Da) and a polyimide of a polyimide precursor.

9. A liquid crystal alignment film obtained from any one of claims 1 to 8.

10. A liquid crystal display element comprising a liquid crystal alignment film as claimed in claim 9.

11. A method for manufacturing a liquid crystal display element, comprising the following steps (1) to (3): Step (1): coating a liquid crystal alignment agent as claimed in any one of claims 1 to 8 onto a substrate; Step (2): calcining the coated liquid crystal alignment agent to obtain a film; Step (3): performing alignment treatment on the film obtained in step (2).

12. A method for manufacturing a liquid crystal display element as claimed in claim 11, wherein, This alignment process is an optical alignment process.

13. A diamine represented by the following formula (da-1), where n is an integer from 6 to 20, and the hydrogen atoms on the benzene ring may also be substituted with monovalent groups.

14. A polymer obtained from a diamine component containing the diamine of claim 13.

15. A polyimide precursor or a polyimide thereof, the polyimide precursor being obtained by a polycondensation reaction of a diamine component containing the diamine of claim 13 and a tetracarboxylic acid component.

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