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

Abstract

Provided are: a liquid crystal alignment agent containing a new solvent component that is suitable for liquid crystal alignment agents; a liquid crystal alignment film obtained from the liquid crystal alignment agent; and a liquid crystal display element using same. Also provided is a liquid crystal display element from which superior display characteristics are obtained even when a liquid crystal alignment film is caused to have an improved application property with respect to end portions and is used for a liquid crystal display element having a large display surface.　This liquid crystal alignment agent contains: at least one polymer (P) selected from the group consisting of polyimide precursors and polyimides that are imidized products of said polyimide precursors; and a solvent component containing a compound (a) represented by formula (A).

Description

[Technical Field]

[0001] The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film. [Background technology]

[0002] Conventionally, various driving methods have been developed for liquid crystal display elements, differing in electrode structure and the physical properties of the liquid crystal molecules used. For example, various display elements such as TN (Twisted Nematic), STN (Super Twisted Nematic), VA (Vertical Alignment), IPS (In Plane Switching), and FFS (Fringe Field Switching) are known. These liquid crystal display elements have a liquid crystal alignment film for aligning the liquid crystal molecules. As materials for the liquid crystal alignment film, for example, polyimide precursors such as polyamic acid and polyamic acid esters, or polymers represented by polyimide are known.

[0003] In VA-type liquid crystal display elements, one of the driving methods for liquid crystal display elements, a technique is known to increase the response speed of the liquid crystal by adding a photopolymerizable compound to the liquid crystal composition in advance, using a vertical alignment film such as a polyimide-based film, and irradiating the liquid crystal cell with ultraviolet light while applying a voltage (PSA (Polymer Sustained Alignment) type element) (see, for example, Patent Document 1 and Non-Patent Document 1). In addition, a technique is known to increase the response speed of the liquid crystal by adding a photopolymerizable compound to a polyimide-based vertical liquid crystal alignment agent, and irradiating a liquid crystal cell equipped with a liquid crystal alignment film obtained from the liquid crystal alignment agent with ultraviolet light while applying a voltage (SC-PVA method (see, for example, Non-Patent Document 2)).

[0004] Liquid crystal alignment agents, which are materials used to form liquid crystal alignment films, have polymer components dissolved in a solvent. A liquid crystal alignment film is formed by coating the liquid crystal alignment agent onto a substrate and heating it. In this case, organic solvents with high polymer solubility, such as aprotic polar solvents like N-methyl-2-pyrrolidone or γ-butyrolactone, are generally used as the solvent for the liquid crystal alignment agent. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2003-307720 [Non-Patent Document 1] K. Hanaoka, SID 04 DIGEST, pp.1200-1202 [Non-Patent Document 2] You-Jin Lee et al.,Optics Express,June 8, 2009,Vol.17, Issue 12,pp.10298-10303 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The above-mentioned N-methyl-2-pyrrolidone and γ-butyrolactone are used in many technological fields, not just as liquid crystal alignment agents, and their usage is expected to increase in the future. Therefore, there is a possibility of supply shortages in the future, making it necessary to search for new solvent components suitable for liquid crystal alignment agents.

[0007] Furthermore, in recent years, liquid crystal display elements have been used in applications such as smartphones and tablet devices. In these applications, in order to secure as much display surface as possible, the sealant used to bond the substrates of the liquid crystal display elements is located close to the edges of the liquid crystal alignment film. Therefore, if the coating properties of the edges of the liquid crystal alignment film deteriorate, that is, if there is a large area where the edges of the liquid crystal alignment film are raised (uneven film thickness at the film edges), the contrast at the edges of the liquid crystal alignment film will fluctuate, degrading the display characteristics of the liquid crystal display element.

[0008] In view of the above circumstances, the object of the present invention is to provide a liquid crystal alignment agent containing a novel solvent component suitable for a liquid crystal alignment agent, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element using the same. Furthermore, the object is to provide a liquid crystal display element that can obtain high display characteristics even when applied to a liquid crystal display element with a large display surface by improving the coatability of the edges of the liquid crystal alignment film. [Means for solving the problem]

[0009] This invention is based on the aforementioned findings and its gist is as follows.

[0010] A liquid crystal alignment agent comprising at least one polymer (P) selected from the group consisting of a polyimide precursor and a polyimide which is an imidized product of the polyimide precursor, and a solvent component containing a compound (a) represented by the following formula (A).

[0011] [ka]

[0012] In this specification, * represents a bond in all cases. Boc represents a tert-butoxycarbonyl group. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine. Examples of carbamate protecting groups include a tert-butoxycarbonyl group and a 9-fluorenylmethoxycarbonyl group. [Effects of the Invention]

[0013] By using compound (a) as at least a part of the solvent component of the liquid crystal aligning agent of the present invention, the coating properties of the polyimide precursor and the polyimide can be improved. More specifically, the uniformity of the film thickness at the edge of the obtained liquid crystal alignment film is improved, and high display characteristics can be obtained even when applied to a liquid crystal display device having a large display surface. In addition to this, the liquid crystal alignment film of the present invention achieves both high film thickness uniformity and high liquid crystal alignment property.

[0014] The mechanism by which the above effects of the present invention are obtained is not necessarily clear, but the following factors are considered. Compound (a) has a higher boiling point and viscosity than N-methyl-2-pyrrolidone, which is mainly used in the liquid crystal aligning agent. Furthermore, since it has a polarized structure, the precipitation of the polyimide precursor and the polyimide is suppressed. Therefore, it is considered that the above effects are obtained because the precipitation of the polyimide precursor and the polyimide does not occur during printing in the liquid crystal aligning agent using compound (a), and the coating dimensions are highly controlled.

Brief Description of the Drawings

[0015] [Figure 1] It is a diagram showing a polyimide film printed on a Cr-deposited substrate and film thickness unevenness. [Figure 2] It is a diagram showing film thickness unevenness of the edge portion of the polyimide film obtained by magnifying the dotted line portion in FIG. 1 with an optical microscope.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, each component included in the liquid crystal aligning agent of the present disclosure and other components optionally blended as necessary will be described. <Polymer (P)> The liquid crystal alignment agent of the present invention contains at least one polymer (P) selected from the group consisting of a polyimide precursor and a polyimide which is an imidized product of the polyimide precursor. Examples of the polyimide precursor include polyamic acid and polyamic acid esters. In addition, as the tetracarboxylic acid component for obtaining the polymer (P), not only tetracarboxylic acid dianhydride but also derivatives of tetracarboxylic acid dianhydride such as tetracarboxylic acid, tetracarboxylic acid dihalide, tetracarboxylic acid dialkyl ester, or tetracarboxylic acid dialkyl ester dihalide can be used.

[0017] (Polyamic acid) The polyamic acid (P'), which is a polyimide precursor of the polymer (P) described above, can be obtained by a polymerization reaction between a diamine component and a tetracarboxylic acid component containing a tetracarboxylic dianhydride or a derivative thereof.

[0018] (Diamine) The diamine component used in the production of the above-mentioned polyamic acid (P') can be a variety of diamines depending on the purpose. The diamine used in the production of polyamic acid (P') may be used alone or in combination of two or more types. Preferred specific examples of the diamine used in the production of polyamic acid (P') (hereinafter also referred to as diamine (p)) include the following diamines.

[0019] Aromatic diamines represented by "AXJ" (the definitions of A, X, and J will be described later) (d), 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'-diaminobiphenyl, 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, 1,5-diaminonaphthalene, 1,6-diaminonaphthalene, 1,7-diaminonaphthalene, 2,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,7-diaminonaphthalene, bis(4-aminophenoxy)methane, 1,2-bis(4-aminophenyl)ethane, 1,2-bis(4-aminophenoxy)ethane, 1,3-bis(3-aminophenyl)propane, 1,4-bis(4-aminophenyl)butane, 1,4-bis(4-amino-2-methylphenyloxy)butane, 1,4-bis(3-aminophenyl)butane, bis(3,5-diethyl-4-aminophenyl)methane, 1,5-bis(4 -aminophenoxy)pentane, 1,5-bis(3-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, 1,6-bis(3-aminophenoxy)hexane, 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, 3-[2-[2-(4-aminophenoxy)ethoxy]ethoxy]benzeneamine, 1,4-Bis(4-aminophenoxy)benzene, 1,3-Bis(4-aminophenoxy)benzene, 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-naphthyloxy)ethane, 1,2-Bis(6-amino-2-naphthyl)ethane, 6-[2-(4-aminophenoxy)ethoxy]-2-naphthylamine, 4'-[2-(4-aminophenoxy)ethoxy]-[1,1'-biphenyl]-4-amine, 1,4-Bis[2-(4-aminophenyl)ethyl]butanediate, 1,6-Bis[ 2-(4-aminophenyl)ethyl]hexanediate, 1,4-phenylenebis(4-aminobenzoate), 1,4-phenylenebis(3-aminobenzoate), 1,3-phenylenebis(4-aminobenzoate), 1,3-phenylenebis(3-aminobenzoate), bis(4-aminophenyl)terephthalate, bis(3-aminophenyl)terephthalate, bis(4-aminophenyl)isophthalate, bis(3-aminophenyl)isophthalate (hereinafter, these diamines are also called diamine(1)); 4,4'-diaminoazobate Nzen, diaminotran, 4,4'-diaminochalcone, or [4-[(E)-3-[2-(2,4-diaminophenyl)ethoxy]-3-oxo-propa-1-enyl]phenyl]4-(4,4,4-trifluorobutoxy)benzoate, or [4-[(E)-3-[[5-amino-2-[4-amino-2-[[(E)-3-[4-[4-(4,4,4-trifluorobutoxy)benzoyl]oxyphenyl]propa-2-enoyl]oxymethyl]phenyl]phenyl]methoxy]-3-oxo-propa-1-enyl]phenyl]4-(4,4Diamines having photo-directing groups, such as aromatic diamines with a cinnamate structure in the side chain, represented by 4-trifluorobutoxy)benzoate; diamines having photopolymerizable groups at the terminal, such as 2-(2,4-diaminophenoxy)ethyl methacrylate and 2,4-diamino-N,N-diallylaniline; benzoin, represented by 1-(4-(2-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylpropanone and 2-(4-(2-hydroxy-2-methylpropanoyl)phenoxy)ethyl-3,5-diaminobenzoate. Diamines having groups in their molecules that exhibit radical polymerization initiator functions, such as alkyl ether derivatives thereof, benzyl ketals, acetophenones, acylphosphine oxides, benzophenones, or aminobenzophenones (hereinafter also referred to as diamines with radical initiation function); diamines having amide bonds, such as 4,4'-diaminobenzanilide; diamines having urea bonds, such as 1,3-bis(4-aminophenyl)urea, 1,3-bis(4-aminobenzyl)urea, and 1,3-bis(4-aminophenethyl)urea; 4,4 '-Sulfonyldianiline, 3,3'-Sulfonyldianiline, Bis(4-aminophenyl)silane, Bis(3-aminophenyl)silane, Dimethyl-bis(4-aminophenyl)silane, Dimethyl-bis(3-aminophenyl)silane, 4,4'-Thiodianiline, 3,3'-Thiodianiline, 3,3'-Diaminodiphenyl ether, 3,4'-Diaminodiphenyl ether, 4,4'-Diaminodiphenyl ether, 2,2-Bis[4-(4-aminophenoxy)phenyl]propane, 2,2-Bis[4-(4-aminophenoxy)phenyl] Xafluoropropane, 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, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 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-diaminoacrididine, N-ethyl-3,6-diaminocarbazole Bazole, N-phenyl-3,6-diaminocarbazole, N-(3-(1H-imidazole-1-yl)propyl-3,5-diaminobenzamide, 4-[4-[(4-aminophenoxy)methyl]-4,5-dihydro-4-methyl-2-oxazolyl]benzeneamine, 1,4-bis(p-aminobenzyl)piperazine, 4,4'-[propane-1,3-diylbis(piperidine-1,4-diyl)]dianiline, 4-(4-ami (Nophenoxycarbonyl)-1-(4-aminophenyl)piperidine, diamines represented by the following formulas (z-1) to (z-5), 2,5-bis(4-aminophenyl)pyrrole, 4,4'-(1-methyl-1H-pyrrole-2,5-diyl)bis[benzeneamine], 1,4-bis-(4-aminophenyl)-piperazine, 2-N-(4-aminophenyl)pyridine-2,5-diamine, 2-N-(5-aminopyridine-2-yl)pyrid Heterocyclic diamines such as n-2,5-diamine, 2-(4-aminophenyl)-5-aminobenzimidazole, 2-(4-aminophenyl)-6-aminobenzimidazole, 5-(1H-benzimidazole-2-yl)benzene-1,3-diamine, or 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl-N-methylamine, N,N'-bis(4-aminophenyl)-1,4-benzenediamine, N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine, or N,N'-bis(4-aminophenyl)-N,N'-dimethyl-1,Diamines having a diphenylamine structure, such as 4-benzenediamine, which have at least one nitrogen-containing structure selected from the group consisting of a nitrogen-containing heterocycle, a secondary amino group, and a tertiary amino group (hereinafter also referred to as a specific nitrogen-containing structure), (however, they do not have amino groups to which protecting groups that are eliminated by heating and replaced by hydrogen atoms are attached in the molecule); 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, 4,4'-diaminobiphenyl-3-carboxylic acid, 4,4'-diaminodiphenylmethane-3- Carboxy groups such as carboxylic acids, 4,4'-diaminodiphenylethane-3-carboxylic acid, 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. Diamines containing: 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 4,4'-diamino-3,3'-dihydroxybiphenyl; 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 1-(4-aminophenyl)-1,3,3-trimethyl-1H-indane-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indane-6-amine; N,N'-bis(2-tert-butoxycarbonylamino-4-aminophenyl)adipamide, 4-amino-N-(2-tert-butoxycarbonylamino-4-aminophenyl)benzamide, carbamic acid, N-[(2,5-diaminophenyl)methyl]-,1,1-dimethylethyl ester, carbamic acid, N-[3-(2,5-diaminophenyl)propyl]-,1,1-dimethylethyl ester, carbamic acid, N,N-[(2,5-diamino-1,3-phenylene)di-3,1-propanediyl]bis-,C,C-bis(1,1-Dimethylethyl) ester, N-tert-butoxycarbonyl-N-(2-(4-aminophenyl)ethyl)-N-(4-aminobenzyl)amine, benzoic acid, 4-amino-2-tert-butoxycarbonylamino-,1,1'-[(1,1,3,3-tetramethyl-1,3-disiloxanediyl)di-4,1-butanediyl] ester, carbamic acid, N-[2-(4, Groups such as -aminophenyl)ethyl]-N-[[[2-(4-aminophenyl)ethyl]amino]carbonyl]-,1,1-dimethylethyl ester, carbamic acid, N-(4-aminophenyl)-N-[[1-(4-aminophenyl)-4-piperidinyl]methyl]-,1,1-dimethylethyl ester, etc., "-N(D)-" (where D represents a protecting group that is removed by heating and replaced by a hydrogen atom, preferably tert-butoxyl) Diamines having a vonyl group; 1-dodecanoxy-2,4-diaminobenzene, 1-tetradecanoxy-2,4-diaminobenzene, 1-pentadecanoxy-2,4-diaminobenzene, 1-hexadecanoxy-2,4-diaminobenzene, 1-octadecanoxy-2,4-diaminobenzene, 1-dodecanoxy-2,5-diaminobenzene, 1-tetradecanoxy-2,5-diaminobenzene, 1-pentadecanoxy Aromatic diamines having long-chain alkyl groups with 12 to 20 carbon atoms, such as xy-2,5-diaminobenzene, 1-hexadecanoxy-2,5-diaminobenzene, and 1-octadecanoxy-2,5-diaminobenzene (tn); diamines having siloxane bonds, such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane and 1,3-bis[3-(p-aminophenylcarbamoyl)propyl]tetramethyldisiloxane; metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), and diamines in which two amino groups are bonded to a group represented by any of the formulas (Y-1) to (Y-167) described in International Publication No. 2018 / 117239.

[0020] [ka] (In equation (z-2), m may be the same or different.)

[0021] In the above aromatic diamine (d), A represents a monovalent group in which two primary amino groups are bonded to an aromatic group. Specific examples of aromatic groups include benzene rings, naphthalene rings, and biphenyl structures. X represents a single bond, -(CH2) a -(a is an integer between 1 and 15), -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -COO-, -OCO-, or -(A0) m0 -((CH2) a1 -A1) m1 -(a1 is an integer from 1 to 15, A 0、 Each A1 independently represents an oxygen atom or -COO-, m0 is an integer of 0 or 1, and m1 is an integer of 1 to 2. If m1 is 2, then multiple a1 and A1 each independently have the above definition.

[0022] J represents a monovalent organic group having at least one group selected from the group consisting of alicyclic hydrocarbon groups having 4 to 40 carbon atoms and aromatic hydrocarbon groups having 6 to 40 carbon atoms. However, at least one of the hydrogen atoms in the above alicyclic hydrocarbon group and aromatic hydrocarbon group is substituted by a substituent (v) which is one of the following: a halogen atom, a halogen atom-containing alkyl group, a halogen atom-containing alkoxy group, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, and an alkenyl group having 3 to 10 carbon atoms. Furthermore, any carbon-carbon single bond in these substituents (v) (except for halogen atoms) may be interrupted by -O-. In addition, J may further have at least one group selected from the group consisting of alicyclic hydrocarbon groups and aromatic hydrocarbon groups that are unsubstituted or substituted with substituents other than the substituents (v) described above.

[0023] Examples of halogen atom-containing alkyl groups include halogen atom-containing alkyl groups having 1 to 10 carbon atoms.

[0024] Examples of the halogen atom-containing alkoxy group include a halogen atom-containing alkoxy group having 1 to 10 carbon atoms.

[0025] Examples of the alicyclic hydrocarbon group of J include a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cyclodecane ring, a steroid skeleton (for example, a cholestanyl group, a cholesteryl group, a lanostanyl group, etc.), and examples of the aromatic hydrocarbon group include a benzene ring, a naphthalene ring, etc. When J has at least one of a cyclohexane ring and a benzene ring, examples of the group “-X-J” include the following structure (S1), and more preferable structures include the following formulas (S1-1) to (S1-5).

[0026] [Chemical formula]

[0027] X 1 is a single bond, -(CH2) a -(a is an integer of 1 to 15), -CONH-, -CO-N(CH3)-, -NH-, -O-, -COO-, or -(A0) m0 -((CH2) a1 -A1) m1 -(a1 is an integer of 1 to 15, A0 and A1 each independently represent an oxygen atom or -COO-, m0 is an integer of 0 or 1, and m1 is an integer of 1 to 2. When m1 is 2, a plurality of a1 and A1 each independently have the above definition.).

[0028] G 1 represents a divalent cyclic group selected from a phenylene group and a cyclohexylene group. Any hydrogen atom on the cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluorine-containing alkyl group having 1 to 3 carbon atoms, a fluorine-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom.

[0029] m is an integer between 1 and 4. If m is 2 or greater, multiple X 1 , G 1 Each of these has its own independent definition.

[0030] R 1 This represents a fluorine atom, a fluorine atom-containing alkyl group having 1 to 10 carbon atoms, a fluorine atom-containing alkoxy group having 1 to 10 carbon atoms, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, or an alkoxyalkyl group having 3 to 10 carbon atoms.

[0031] [ka]

[0032] X 1 , R 1 X in the above equation (S1) is 1 , R 1 It is synonymous with [the above]. Specific examples of the above aromatic diamine (d) include diamines represented by the following formulas (d-1) to (d-2). More preferred examples include diamines represented by formulas (d-1) to (d-2) in which the group "-XJ" is one of the above structure (S1) or the above formulas (S1-1) to (S1-5), as well as diamines having a steroid skeleton such as cholestanyloxy-3,5-diaminobenzene, cholestanyloxy-3,5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestanyl 3,5-diaminobenzoate, cholestenyl 3,5-diaminobenzoate, lanostanyl 3,5-diaminobenzoate, and 3,6-bis(4-aminobenzoyloxy)cholestane.

[0033] [ka]

[0034] X and J are synonymous with X and J of the above aromatic diamine (d), including preferred embodiments. In formula (d-2), the two X and J may be the same or different from each other. As the above-mentioned diamine (p), for example, it can be appropriately selected and used from the above-mentioned diamines depending on the driving mode of the liquid crystal display element to be manufactured. Specifically, by using the above-mentioned diamine (1), the above-mentioned diamine having a specific nitrogen-containing structure, or the above-mentioned diamine having a urea bond as the above-mentioned diamine (p), a liquid crystal alignment agent suitable for IPS type and FFS type liquid crystal display elements can be manufactured. Furthermore, by using the above-mentioned diamine (1) or aromatic diamine (tn), a liquid crystal alignment agent suitable for TN type liquid crystal display elements can be manufactured, and by using the above-mentioned aromatic diamine (d), a liquid crystal alignment agent suitable for VA type liquid crystal display elements can be manufactured. Furthermore, by using the above-mentioned diamine having a radical initiation function or a diamine having a photopolymerizable group at its terminal, a liquid crystal alignment agent suitable for PSA type and SC-PVA type liquid crystal display elements can be manufactured. Furthermore, when imparting photo-orientation properties to the polyamic acid (P'), a diamine having the above-mentioned photo-orientation group can be used as the diamine (p). In addition, when imparting solubility to the polyamic acid (P'), a diamine having the above-mentioned carboxyl group, a diamine having the above-mentioned group "-N(D)-", or a diamine (K) having -Ar-K-Ar- (Ar represents an unsubstituted or substituted phenylene group; K represents -C(CH3)2-, -C(CF3)2-, -O-, or -CH2-; and the -Ar-K-Ar- is formed in the direction of the main chain of the polymer) can be used. Specific examples of diamines (K) include 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 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, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, and 4,4'-diaminodiphenylmethane.

[0035] When the above aromatic diamine (d) is used as the above diamine (p), 5 to 95 mol% and more preferably 10 to 90 mol% of the total diamine component used to produce the polyamic acid (P') is preferred. When using the above-mentioned diamine (p), the above-mentioned diamine (1), the above-mentioned diamine having a specific nitrogen-containing structure, or the above-mentioned diamine having a urea bond, the diamine (p) is preferably 5 to 95 mol%, and more preferably 10 to 90 mol%, of the total diamine component used to produce the polyamic acid (P'). When using a diamine (p) having a photo-directing group, a diamine having a radical initiation function, or a diamine having a photopolymerizable group at its terminus, it is preferable that the diamine component used to produce polyamic acid (P') is 5 to 60 mol%, and more preferably 10 to 60 mol%. When using a diamine having the carboxyl group or a diamine having the group "-N(D)-" as the above diamine (p), 5 to 90 mol% and more preferably 10 to 80 mol% of the total diamine component used to produce polyamic acid (P') is preferred.

[0036] (Tetracarboxylic acid dianhydride) The tetracarboxylic dianhydrides that can be used in the synthesis of the above polyamic acid (P') include at least one compound selected from the group consisting of acyclic aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, and aromatic tetracarboxylic dianhydrides. In particular, it is more preferable to include a tetracarboxylic dianhydride having at least one substructure selected from the group consisting of a benzene ring, a cyclobutane ring structure, a cyclopentane ring structure, and a cyclohexane ring structure, and even more preferable to include a tetracarboxylic dianhydride having at least one substructure selected from the group consisting of a cyclobutane ring structure, a cyclopentane ring structure, and a cyclohexane ring structure. Aromatic tetracarboxylic dianhydrides are acidic dianhydrides obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to the aromatic ring. Acyclic aliphatic tetracarboxylic dianhydrides are acidic dianhydrides obtained by intramolecular dehydration of four carboxyl groups bonded to a chain-like hydrocarbon structure. However, they do not need to consist solely of chain-like hydrocarbon structures; they may also contain alicyclic or aromatic ring structures as part of their structure. Alicyclic tetracarboxylic dianhydrides are acidic dianhydrides obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to the alicyclic structure. However, none of these four carboxyl groups are bonded to an aromatic ring. Furthermore, they do not need to consist solely of alicyclic structures; they may also contain a chain-like hydrocarbon structure or an aromatic ring structure as part of their composition. The tetracarboxylic acid components that can be used in the synthesis of polyamic acid (P') preferably include the following tetracarboxylic dianhydrides or their derivatives (hereinafter collectively referred to as specific tetracarboxylic acid derivatives).

[0037] Furthermore, the above-mentioned tetracarboxylic dianhydride or its derivative may be used individually or in combination of two or more types.

[0038] Acyclic aliphatic tetracarboxylic dianhydrides such as 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-dichloro-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-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 acid dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)tetrahydronaphthalene-1,2-dicarboxylic acid dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3- Dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, bicyclo[2.2.2]octa-7-en-2,3,5,6-tetracarboxylic dianhydride, bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic dianhydride, 2,4,6,8-tetracarboxybicyclo[3.3.0] Alicyclic tetracarboxylic dianhydrides such as octane-2:4,6:8-dianhydride; pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenylsulfone tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3',4,4'-biphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-perfluoroisopropylidene diphthalic acid dianhydride, 3,3',4,4'-biphenyl tetracarboxylic dianhydride, 2,2 Aromatic tetracarboxylic dianhydrides such as ',3,3'-biphenyltetracarboxylic dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylpropane dianhydride, ethylene glycol bisanhydrotrimellitate, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 4,4'-carbonyldiphthalic anhydride, 4,4'-oxydi(1,4-phenylene)bis(phthalic acid) dianhydride, or 4,4'-methylenedi(1,4-phenylene)bis(phthalic acid) dianhydride; and other tetracarboxylic dianhydrides described in Japanese Patent Publication No. 2010-97188.

[0039] Preferred examples of the above-mentioned specific tetracarboxylic acid derivatives include 1,2,3,4-butanetetracarboxylic acid dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,3-difluoro-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,3-bis(trifluoromethyl)-1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride, 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, 3,3',4,4'-dicyclohexyltetracarboxylic acid dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 5-(2, 5-Dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, pyromellitic dianhydride, 3,3',4,4 These are '-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenylsulfonetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3',4,4'-biphenylethertetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 2,2',3,3'-biphenyltetracarboxylic dianhydride.

[0040] The proportion of the above-mentioned specific tetracarboxylic acid derivative used is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 50 mol% or more, based on 1 mole of the total tetracarboxylic acid component used.

[0041] (Synthesis of polyamic acids) The synthesis of polyamic acids is carried out by reacting a diamine component containing the above-mentioned diamine with a tetracarboxylic acid component containing the above-mentioned tetracarboxylic dianhydride or a derivative thereof in an organic solvent. The ratio of tetracarboxylic dianhydride to diamine used in the synthesis reaction of polyamic acids is preferably such that the acid anhydride groups of the tetracarboxylic dianhydride are in the proportion of 0.5 to 2 equivalents, and more preferably 0.8 to 1.2 equivalents, per 1 equivalent of amino groups of the diamine. As with ordinary polycondensation reactions, the closer the equivalent amount of acid anhydride groups of the tetracarboxylic dianhydride is to 1 equivalent, the larger the molecular weight of the resulting polyamic acid.

[0042] The reaction temperature for the synthesis of polyamic acids is preferably -20 to 150°C, and more preferably 0 to 100°C. The reaction time is preferably 0.1 to 24 hours, and more preferably 0.5 to 12 hours.

[0043] The synthesis reaction of polyamic acids can be carried out at any concentration, but preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction can be carried out at a high concentration initially, and then the solvent can be added.

[0044] Specific examples of the above organic solvents include compound (a), 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-imidazolidinone. Furthermore, if the solvent solubility of the polymer is high, 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.

[0045] (Synthesis of polyamic acid SL) Polyamic acid esters can be obtained by known methods, such as [I] reacting the polyamic acid obtained by the above method with an esterifying agent, [II] reacting a tetracarboxylic acid diester with a diamine, or [III] reacting a tetracarboxylic acid dihalide with a diamine.

[0046] (Synthesis of polyimides) Furthermore, polyimides can be obtained by cyclizing (imidizing) polyimide precursors such as the above-mentioned polyamic acid or polyamic acid ester. In this specification, the imidization rate refers to the ratio of imide groups to the total amount of imide groups and carboxyl groups (or their derivatives) derived from tetracarboxylic dianhydride or its derivatives. The imidization rate does not necessarily have to be 100% and can be arbitrarily adjusted depending on the application and purpose. For example, from the viewpoint of ensuring the solubility of the polyimide, the imidization rate may be 30% or more, 40-99%, or 50-99%.

[0047] Methods for imidizing a polyimide precursor include thermal imidation, which involves heating the polyimide precursor solution directly, and catalytic imidation, which involves adding a catalyst to the polyimide precursor solution.

[0048] The temperature at which the polyimide precursor is thermally imidized in solution is preferably 100 to 400°C, more preferably 120 to 250°C, and it is preferable to remove the water produced by the imidization reaction from the system.

[0049] Catalytic imidation of polyimide precursors can be carried out by adding a basic catalyst and an acid anhydride to a solution of the polyimide precursor and stirring at a temperature preferably -20 to 250°C, more preferably 0 to 180°C. The amount of basic catalyst is preferably 0.5 to 30 molar times, more preferably 2 to 20 molar times, of the amic acid groups, and the amount of acid anhydride is preferably 1 to 50 molar times, more preferably 3 to 30 molar times, of the amic acid groups. Examples of basic catalysts include pyridine, triethylamine, trimethylamine, tributylamine, or trioctylamine, with pyridine being preferred because it has a suitable basicity for the reaction to proceed. Examples of acid anhydrides include acetic anhydride, trimellitic anhydride, or pyromellitic anhydride, with acetic anhydride being preferred because it facilitates purification after the reaction. The imidation rate by catalytic imidation can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

[0050] To recover the polyimide precursor or polyimide from a reaction solution of a polyimide precursor, the reaction solution can be placed in a solvent and precipitated. Examples of solvents that can be used for precipitation include methanol, ethanol, isopropyl alcohol, acetone, hexane, butyl cellsolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water. The polymer precipitated in the solvent can be recovered by filtration and then dried at room temperature or under normal or reduced pressure.

[0051] <End capping agent> In synthesizing the polyimide precursor or polyimide in the present invention, a tetracarboxylic acid component containing tetracarboxylic dianhydride or its derivative, and a diamine component containing the above-mentioned diamine, may be used together with a suitable end-sealing agent to synthesize a end-sealed polymer. The end-sealed polymer has the effect of improving the film hardness of the liquid crystal alignment film obtained by the coating film and improving the adhesion characteristics between the sealant and the liquid crystal alignment film.

[0052] Examples of polyimide precursors and polyimide ends in the present invention include amino groups, carboxyl groups, acid anhydride groups, or groups derived from end-capturing agents described later. Amino groups, carboxyl groups, and acid anhydride groups can be obtained by conventional condensation reactions or by encapsulating the ends using the following end-capturing agents.

[0053] Examples of end-capturing agents include acid anhydrides such as acetic anhydride, maleic anhydride, nadic anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic acid anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, 3-(3-trimethoxysilyl)propyl)-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, and 4-ethynylphthalic anhydride; dicarbonate diester compounds such as di-tert-butyl dicarbonate and diallyl dicarbonate; chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride, and nicotinic acid chloride; and aniline Examples include monoamine compounds such as n-aminophenol, 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, and n-octylamine; and isocyanates having unsaturated bonds such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate, or 2-acryloyloxyethyl isocyanate and 2-methacryloyloxyethyl isocyanate.

[0054] The proportion of end-capturing agent used is preferably 0.01 to 20 moles, and more preferably 0.01 to 10 moles, per 100 moles of the total diamine components used.

[0055] The weight-average molecular weight (Mw) of the polyimide precursor and polyimide, measured by gel permeation chromatography (GPC), is preferably 1,000 to 500,000, and 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) measured by GPC, is preferably 15 or less, and more preferably 10 or less. This molecular weight range ensures good orientation of the liquid crystal display element.

[0056] (Liquid crystal alignment agent) The liquid crystal alignment agent of the present invention comprises a polymer (P) and a compound (a) represented by the above formula (A) as a solvent component. Liquid crystal alignment agents are used to produce liquid crystal alignment films, and from the viewpoint of forming a uniform thin film, they preferably take the form of a coating solution. The concentration of polymer in the liquid crystal alignment agent can be appropriately changed depending on the desired thickness of the coating film to be formed. From the viewpoint of forming a uniform and defect-free coating film, the concentration of polymer in the liquid crystal alignment agent (total concentration of polymer components) is preferably 1% by mass or more, and from the viewpoint of the storage stability of the solution, it is preferably 10% by mass or less. A particularly preferred polymer concentration is 2 to 8% by mass. The content of compound (a) can be adjusted as appropriate depending on the purpose. For example, from the viewpoint of improving printability, the content may be 0.1% by mass or more, 1% by mass or more, 5% by mass or more, or 10% by mass or more, relative to the total amount of solvent components contained in the liquid crystal alignment agent. Furthermore, regarding the upper limit of the content, from the viewpoint of printability, it may be 90% by mass or less, 85% by mass or less, or 80% by mass or less, relative to the total amount of solvent components contained in the liquid crystal alignment agent. Compound (a) may contain impurities such as levoglucosan and levoglucocenone. In such cases, the preferred range for the content ratio of compound (a) shall be defined by the amount of compound (a) including these impurities. Compound (a) may be a single stereoisomer or a mixture containing multiple stereoisomers. A commercially available example of compound (a) is Cyrene™ manufactured by Merck.

[0057] Other solvents besides compound (a) above may be used as the solvent for preparing the liquid crystal alignment agent of the present invention. Examples of such other solvents include lactone solvents such as γ-valerolactone, γ-butyrolactone, and α,α-dimethyl-γ-butyrolactone; γ-butyrolactam, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 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, and N-(2-ethoxyethyl)- Lactam solvents such as 2-pyrrolidone, N-(4-methoxybutyl)-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, N-acetyl-ε-caprolactam (N-acetyl-2-oxohexamethyleneimine), N-methyl-ε-caprolactam; N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylpropionamide, N,N-dimethylisobutylamide (N,N,2-trimethylpropionamide), N,N-di Amide solvents such as ethylpropionamide, N,N-dipropylacetamide, N,N-diisopropylacetamide, N,N-dibutylacetamide, N,N-dimethyllactamide, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide; tetramethylurea, N,N'-dimethylpropyleneurea, N-propionylmorpholine, 4-oxotetrahydropyran (tetrahydro-4H-pyran-4-one), tetramethylene sulfoxide, trimethyl phosphate, triethyl phosphate Chil, hexamethyl phosphate triamide, 3-methyl-2-oxazolidone, 1,3-dimethyl-2-imidazolidinone (N,N'-dimethylethylene urea), 1,4-diacetylpiperazine, cyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone (diacetone alcohol), isopropyl acetate, n-butyl acetate, isobutyl acetate, tert-butyl acetate, propylene glycol monoethyl ether acetate, cyclohexyl acetate,4-methyl-2-pentyl acetate, 3-methoxybutyl acetate (3-methoxybutyl acetate), isopropyl lactate, n-butyl lactate, isobutyl lactate, tert-butyl lactate, isoamyl lactate (isopentyl lactate), 2-(2-ethoxyethoxy)ethyl acetate (ethylene glycol monoethyl ether acetate), methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl 2-hydroxyisobutyrate (methyl 2-Hydroxy-2-methylpropionate), ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, ethylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, ethylene glycol diacetate, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol diacetate, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, diethylene glycol Diethylpropyl ether, diethylene glycol butyl methyl ether, diethylene glycol dibutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate (2-(2-ethoxyethoxy)ethyl acetate, carbitol acetate), diethylene glycol monobutyl ether acetate (butyl carbitol acetate), dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, 1-(2-butoxyethoxy)-2-propanol, 2-(2-butoxyethoxy)-1-propanol, diisobutylcarbinol (2,6-dimethyl-4-heptanol),Examples include diisobutyl ketone, isoamyl propionate (isoamyl propionate), isoamyl isobutyrate (isoamyl isobutyrate), diisopentyl ether, ethylene carbonate, and propylene carbonate. Two or more of these can be used in combination.

[0058] The liquid crystal alignment agent of the present invention may contain, as a solvent component, a solvent selected from the group consisting of γ-valerolactone, γ-butyrolactone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 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-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, the above amide solvents, 1,3-dimethyl-2-imidazolidinone, tetramethylurea, hexamethylphosphoramide, cyclohexanone, and cyclopentanone (hereinafter, these are collectively referred to as "solvent (1)"). The content of the above solvent (1) is preferably 20 to 99% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass.

[0059] The liquid crystal alignment agent of the present invention, from the viewpoint of improving the printability of the liquid crystal alignment agent, includes, as a solvent component, 4-hydroxy-4-methyl-2-pentanone, n-butyl acetate, propylene glycol monoethyl ether acetate, cyclohexyl acetate, 4-methyl-2-pentyl acetate, n-butyl lactate, isoamyl lactate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol dimethyl ether, and ethylene glycol monobutyl ether acetate. The liquid crystal alignment agent may contain a solvent selected from the group consisting of propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, diisobutylcarbinol, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, ethylene carbonate, and propylene carbonate (hereinafter, these are collectively referred to as "solvent (2)"). The content of solvent (2) is preferably 5 to 70% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 10 to 60% by mass, and particularly preferably 10 to 50% by mass.

[0060] The solvent component contained in the liquid crystal alignment agent of the present invention may include a combination of multiple solvents. For example, a solvent component containing compound (a) and solvent (1), a solvent component containing compound (a) and solvent (2), and a solvent component containing compound (a), solvent (1), and solvent (2) are examples. Among these, a more preferred specific example is a solvent component including the following embodiments. In the following embodiments, BCS represents ethylene glycol monobutyl ether, PB represents propylene glycol monobutyl ether, DAA represents 4-hydroxy-4-methyl-2-pentanone, DIBK represents diisobutyl ketone, BCA represents ethylene glycol monobutyl ether acetate, PGME represents propylene glycol monomethyl ether, PGMEA represents propylene glycol monomethyl ether acetate, PGA represents propylene glycol diacetate, DEDE represents diethylene glycol diethyl ether, DPM represents dipropylene glycol monomethyl ether, NMP represents N-methyl-2-pyrrolidone, GBL represents γ-butyrolactone, CHN represents cyclohexanone, CPN represents cyclopentanone, 3MDP represents 3-methoxy-N,N-dimethylpropanamide, 3BDP represents 3-butoxy-N,N-dimethylpropanamide, DP represents N,N-dimethylpropionamide, and TMP represents N,N,2-trimethylpropionamide.

[0061] Compound (a) and BCS, Compound (a) and GBL and BCS, Compound (a) and trimethyl phosphate and BCS, Compound (a) and triethyl phosphate and BCS, Compound (a) and PB, Compound (a) and GBL and PB, Compound (a) and NMP and PB, Compound (a) and DAA, Compound (a) and GBL and DAA, Compound (a) and DAA and BCS, Compound (a) and N,N-dimethylisobutylamide and DAA, Compound (a) and NMP and DAA, Compound (a) and N-ethyl-2-pyrrolidone and DAA, Compound (a) and N,N-dimethyllactamide and DAA, Compound (a) and phosphate Rimethyl and DAA, compound (a) and triethyl phosphate and DAA, compound (a) and DAA and 3MDP, compound (a) and DAA and 3BDP, compound (a) and DIBK, compound (a) and GBL and DIBK, compound (a) and γ-valerolactone and DIBK, compound (a) and DIBK and 3MDP, compound (a) and DIBK and 3BDP, compound (a) and DIBK and DAA, compound (a) and DIBK and PB, compound (a) and DEDE, compound (a) and GBL and DEDE, compound (a) and 1,3-dimethyl-2-imidazolidinone and DEDE, compound (a) and NMP and DED E, compound (a) and N-butyl-2-pyrrolidone and DEDE, compound (a) and DEDE and DAA, compound (a) and DEDE and DIBK, compound (a) and DEDE and BCS, compound (a) and DEDE and butyl lactate, compound (a) and NMP and GBL and PB and DIBK, compound (a) and DPM, compound (a) and DPM and DAA, compound (a) and PB and DPM, compound (a) and PGA, compound (a) and PGA and DAA, compound (a) and PGA and PB, compound (a) and diisopropyl ether, compound (a) and PB and diisopropyl ether, compound (a) and diisopropyl ether Diisopentyl ether, compound (a) and NMP and diisopentyl ether, compound (a) and N-ethyl-2-pyrrolidone and diisopentyl ether, compound (a) and N-butyl-2-pyrrolidone and diisopentyl ether, compound (a) and diisobutylcarbinol, compound (a) and diisobutylcarbinol and DIBK, compound (a) and diisobutylcarbinol and PB, compound (a) and dipropylene glycol dimethyl ether, compound (a) and dipropylene glycol dimethyl ether and PB, compound (a) and diethylene glycol ethyl methyl ether,Compound (a) and diethylene glycol ethyl methyl ether and DIBK, Compound (a) and diethylene glycol ethyl methyl ether and PB, Compound (a) and diethylene glycol ethyl propyl ether, Compound (a) and diethylene glycol butyl ethyl ether, Compound (a) and CPN and PGME, Compound (a) and CPN and PB, Compound (a) and CPN and diethylene glycol monoethyl ether, Compound (a) and CPN and PGA, Compound (a) and CPN and DIBK, Compound (a) and CPN and n-butyl acetate, Compound (a) and CHN and n-butyl acetate Compound (a) and CHN and BCS, Compound (a) and CHN and PGME, Compound (a) and tetramethylurea and PGMEA, Compound (a) and CHN and PB, Compound (a) and CHN and diethylene glycol monoethyl ether, Compound (a) and CHN and DIBK, Compound (a) and methyl isobutyl ketone and PB, Compound (a) and methyl ethyl ketone and PB, Compound (a) and CPN and DAA, Compound (a) and CPN and DEDE, Compound (a) and CHN and DAA, Compound (a) and CHN and DEDE, Compound (a) and CHN and PGA, Compound (a) and tetramethylurea and PGME, compound (a) and tetramethylurea and PGA, compound (a) and tetramethylurea and PB, compound (a) and tetramethylurea and CHN and PGME, compound (a) and DP and PGME, compound (a) and DP and PGMEA, compound (a) and DP and PB, compound (a) and DP and BCS, compound (a) and DP and DEDE, compound (a) and N,N-diethylformamide and PGME, compound (a) and N,N-diethylformamide and DAA, compound (a) and N,N-diethylpropionamide and PGME, compound (a) and TMP and PGME, compound (a) and T MP and PGMEA, compound (a) and TMP and PB, compound (a) and TMP and BCS, compound (a) and TMP and DEDE, compound (a) and BCA, compound (a) and BCS and BCA, compound (a) and ethyl 3-ethoxypropionate, compound (a) and GBL and ethyl 3-ethoxypropionate, compound (a) and CHN and ethyl 3-ethoxypropionate, compound (a) and propylene carbonate and ethyl 3-ethoxypropionate, compound (a) and DP and ethyl 3-ethoxypropionate, compound (a) and tetramethylurea and ethyl 3-ethoxypropionate,And compound (a), trimethyl phosphate, ethyl 3-ethoxypropionate, etc.

[0062] The liquid crystal alignment agent of the present invention may also contain other components as needed. Examples of such components include other polymers (Q) other than the polymer (P) described above, at least one crosslinkable compound selected from the group consisting of a crosslinkable compound (c-1) having at least one substituent selected from epoxy groups, oxetanyl groups, oxazoline groups, cyclocarbonate groups, blocked isocyanate groups, hydroxyl groups, and alkoxy groups, and a crosslinkable compound (c-2) having a polymerizable unsaturated group, functional silane compounds, metal chelate compounds, curing accelerators, surfactants, antioxidants, sensitizers, preservatives, and compounds for adjusting the dielectric constant and electrical resistance of the liquid crystal alignment film.

[0063] Other specific examples of polymers (Q) include polymers selected from the group consisting of 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. Specific examples of poly(styrene-maleic anhydride) copolymers include SMA1000, SMA2000, SMA3000 (manufactured by Cray Valley), and GSM301 (manufactured by Gifu Ceratek Manufacturing Co., Ltd.). Specific examples of poly(isobutylene-maleic anhydride) copolymers include Isoban-600 (manufactured by Kuraray Co., Ltd.). Specific examples of poly(vinyl ether-maleic anhydride) copolymers include Gantrez AN-139 (methyl vinyl ether maleic anhydride resin, manufactured by Ashland).

[0064] The other polymer (Q) may be used alone or in combination of two or more. The content of the other polymer (Q) is preferably 50 parts by mass or less, more preferably 1 to 50 parts by mass, and even more preferably 5 to 40 parts by mass, based on 100 parts by mass of the total amount of polymers contained in the liquid crystal alignment agent. Preferred specific examples of the above crosslinkable compounds (c-1) and (c-2) include the following compounds.

[0065] Compounds containing epoxy groups include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromo neopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, and bisphenol A type epoxy resins such as Epicote 828 (manufactured by Mitsubishi Chemical Corporation). Bisphenol F type epoxy resins such as Epicote 807 (Mitsubishi Chemical Corporation), hydrogenated bisphenol A type epoxy resins such as YX-8000 (Mitsubishi Chemical Corporation), biphenyl skeleton-containing epoxy resins such as YX6954BH30 (Mitsubishi Chemical Corporation), phenol novolac type epoxy resins such as EPPN-201 (Nippon Kayaku Co., Ltd.), (o,m,p-)cresol novolac type epoxy resins such as EOCN-102S (Nippon Kayaku Co., Ltd.), tetrakis(glycidyloxymethyl)methane, N,N,N',N'-tetraglycidyl-1,4-phenylenediamine, N,N,N',N'-tetraglycidyl-2,2'-dimethyl-4.Compounds in which a tertiary nitrogen atom is bonded to an aromatic carbon atom, such as 4'-diaminobiphenyl, 2,2-bis[4-(N,N-diglycidyl-4-aminophenoxy)phenyl]propane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane; N,N,N',N'-tetraglycidyl-1,2-diaminocyclohexane, N,N,N',N'-tetraglycidyl-1,3-diaminocyclohexane, N,N,N',N'-tetraglycidyl-1,4-diaminocyclohexane, bis(N,N-diglycidyl-4-aminocyclohexyl)methane, bis(N,N-diglycidyl-2-methyl-4-aminocyclohexyl)methane, bis(N,N-diglycidyl-3-methyl-4-aminocyclohexyl)methane Compounds in which a tertiary nitrogen atom is bonded to an aliphatic carbon atom, such as tan, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,4-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,3-bis(N,N-diglycidylaminomethyl)benzene, 1,4-bis(N,N-diglycidylaminomethyl)benzene, 1,3,5-tris(N,N-diglycidylaminomethyl)cyclohexane, and 1,3,5-tris(N,N-diglycidylaminomethyl)benzene; isocyanurate compounds such as triglycidyl isocyanurates (manufactured by Nissan Chemical Corporation); compounds described in paragraph

[0037] of Japanese Patent Publication No. 10-338880; and compounds described in International Publication No. 2017 / 170483, etc. Examples of compounds having an oxetanyl group include 1,4-bis{[(3-ethyl-3-oxetanyl)methoxy]methyl}benzene (Aronoxetane OXT-121(XDO)), di[2-(3-oxetanyl)butyl]ether (Aronoxetane OXT-221(DOX)), 1,4-bis[(3-ethyloxetan-3-yl)methoxy]benzene (HQOX), 1,3-bis[(3-ethyloxetan-3-yl)methoxy]benzene (RSOX), 1,2-bis[(3-ethyloxetan-3-yl)methoxy]benzene (CTOX), and compounds having two or more oxetanyl groups as described in paragraphs

[0170] to

[0175] of International Publication No. 2011 / 132751; Compounds having an oxazoline group include compounds such as 2,2'-bis(2-oxazoline) and 2,2'-bis(4-methyl-2-oxazoline), polymers and oligomers having an oxazoline group such as Epocross (trade name, manufactured by Nippon Shokubai Co., Ltd.), and compounds described in paragraph

[0115] of Japanese Patent Publication No. 2007-286597; Examples of compounds having a cyclocarbonate group include N,N,N',N'-tetra[(2-oxo-1,3-dioxolan-4-yl)methyl]-4,4'-diaminodiphenylmethane, N,N'-di[(2-oxo-1,3-dioxolan-4-yl)methyl]-1,3-phenylenediamine, and the compounds described in paragraphs

[0025] to

[0030] and

[0032] of Publication No. WO2011 / 155577; Examples of compounds having blocked isocyanate groups include Coronate AP Stable M, Coronate 2503, 2515, 2507, 2513, 2555, Millionate MS-50 (all manufactured by Tosoh Corporation), Takenate B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, B-882N (all manufactured by Mitsui Chemicals, Inc.), compounds having two or more protected isocyanate groups as described in paragraphs

[0046] to

[0047] of Japanese Patent Publication No. 2014-224978, and compounds having three or more protected isocyanate groups as described in paragraphs

[0119] to

[0120] of WO2015 / 141598; Compounds having hydroxyl and alkoxy groups include N,N,N',N'-tetrakis(2-hydroxyethyl)adipoamide, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethoxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)-1,1,1,3,3,3-hexafluoropropane, compounds described in International Publication No. 2015 / 072554, paragraph

[0058] of Japanese Patent Publication No. 2016-118753, compounds described in Japanese Patent Publication No. 2016-200798, compounds described in International Publication No. 2010 / 074269, etc. Examples of crosslinkable compounds having polymerizable unsaturated groups include glycerin mono(meth)acrylate, glycerin di(meth)acrylate (1,2-,1,3-compound mixture), glycerin tris(meth)acrylate, glycerol 1,3-diglycerolate 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, hexaethylene glycol mono(meth)acrylate, etc.

[0066] The content of the crosslinkable group-containing compounds (c-1) and (c-2) contained in the liquid crystal alignment agent of the present invention is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, and even more preferably 1 to 10 parts by mass, based on 100 parts by mass of the total polymer components contained in the liquid crystal alignment agent.

[0067] Examples of compounds used to adjust dielectric constant and electrical resistance include monoamines having nitrogen-containing aromatic heterocycles, such as 3-picolylamine. When using monoamines having nitrogen-containing aromatic heterocycles, the amount is preferably 0.1 to 30 parts by mass, and more preferably 0.1 to 20 parts by mass, per 100 parts by mass of the polymer component contained in the liquid crystal alignment agent.

[0068] Preferred specific examples of functionalized silane compounds include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, Examples include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris[3-(trimethoxysilyl)propyl]isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatetopropyltriethoxysilane. When using functionalized silane compounds, the amount is preferably 0.1 to 30 parts by mass, and more preferably 0.1 to 20 parts by mass, per 100 parts by mass of the polymer component contained in the liquid crystal alignment agent.

[0069] The solid content concentration in the liquid crystal alignment agent (the ratio of the total mass of components other than the solvent to the total mass of the liquid crystal alignment agent) is appropriately selected considering viscosity, volatility, etc., but is preferably 1 to 10% by mass. The range of particularly preferred solid content concentrations differs depending on the method used to coat the liquid crystal alignment agent onto the substrate. For example, when using the spin coating method, a solid content concentration of 1.5 to 4.5% by mass is particularly preferred. When using the printing method, a solid content concentration of 3 to 9% by mass is particularly preferred, resulting in a solution viscosity of 12 to 50 mPa·s. When using the inkjet method, a solid content concentration of 1 to 5% by mass is particularly preferred, resulting in a solution viscosity of 3 to 15 mPa·s.

[0070] <Liquid crystal alignment film> The liquid crystal alignment film of the present invention is obtained from the above-mentioned liquid crystal alignment agent. The liquid crystal alignment film of the present invention can be used as a horizontally aligned or vertically aligned liquid crystal alignment film. Among the vertically aligned liquid crystal alignment films, those used in vertically aligned liquid crystal display elements such as VA type, PSA type, or SC-PVA type are preferred. Furthermore, the liquid crystal alignment agent of the present invention can be used as a liquid crystal alignment film for phase difference films, a liquid crystal alignment film for scanning antennas or liquid crystal array antennas, or a liquid crystal alignment film for transmission-scattering type liquid crystal dimming elements, or for other applications such as protective films for color filters, gate insulating films for flexible displays, and substrate materials.

[0071] <Liquid crystal display element> The liquid crystal display element of the present invention comprises the above-mentioned liquid crystal alignment film. The liquid crystal alignment agent of the present invention is preferably used in liquid crystal display elements that have a liquid crystal layer between a pair of substrates equipped with electrodes, and are manufactured by placing a liquid crystal composition containing a polymerizable compound that polymerizes by at least one of active energy rays and heat between the pair of substrates, and polymerizing the polymerizable compound by irradiation with active energy rays and heating while applying a voltage between the electrodes.

[0072] The liquid crystal display element of the present invention can be manufactured, for example, by performing the following steps (1) to (3) or steps (1) to (4) in that order. (1) A step of applying a liquid crystal alignment agent onto at least one of a pair of substrates having a conductive film to form a coating film. A patterned transparent conductive film is applied to at least one surface of one of a pair of substrates, using an appropriate coating method such as a roll coater, spin coat, printing, or inkjet to create a coating film. The substrate is not particularly limited as long as it is highly transparent, and can be glass substrates, silicon nitride substrates, as well as plastic substrates such as acrylic substrates and polycarbonate substrates. In the case of a reflective liquid crystal display element, an opaque material such as a silicon wafer can be used for only one of the substrates, and in this case, a light-reflecting material such as aluminum can be used for the electrodes. (2) Process of firing the coating film After applying the liquid crystal alignment agent, the coating film is baked to prevent dripping of the applied alignment agent. Preferably, preheating (pre-bake) is performed first. The pre-bake temperature is preferably 30 to 200°C, more preferably 40 to 150°C, and particularly preferably 40 to 100°C. The pre-bake time is preferably 0.25 to 10 minutes, and more preferably 0.5 to 5 minutes. Then, a heating (post-bake) step is preferably performed. The post-bake temperature is preferably 80 to 300°C, and more preferably 120 to 250°C. The post-bake time is preferably 5 to 200 minutes, and more preferably 10 to 100 minutes. The film thickness of the film formed in this way is preferably 5 to 300 nm, and more preferably 10 to 200 nm.

[0073] The coating film formed in steps (1) and (2) above can be used as is as a liquid crystal alignment film, but the coating film may also be subjected to an alignment-imparting treatment. Examples of alignment-imparting treatments include rubbing, in which the coating film is rubbed in a certain direction with a roll wrapped with a cloth made of fibers such as nylon, rayon, or cotton, and photo-alignment, in which the coating film is irradiated with polarized or unpolarized radiation.

[0074] In photo-alignment processing, ultraviolet and visible light, including wavelengths of 150 to 800 nm, can be used as radiation to irradiate the coating film. If the radiation is polarized, it may be linearly polarized or partially polarized. Furthermore, if the radiation used is linearly polarized or partially polarized, irradiation may be performed perpendicular to the substrate surface, at an oblique angle, or a combination of these. When irradiating with unpolarized radiation, the irradiation direction should be oblique. (3) A process of forming a liquid crystal layer between the pair of substrates to produce a liquid crystal cell. (3-1) When manufacturing a VA type liquid crystal display element As described above, two substrates are prepared, each having a liquid crystal alignment film of the present invention formed on at least one of them, and liquid crystal is placed between the two substrates which are placed opposite each other. Specifically, the following two methods can be used. The first method is a conventionally known method. First, two substrates are placed opposite each other with a gap (cell gap) in between so that their respective liquid crystal alignment films face each other. Next, a sealant is applied to the periphery of the two substrates and they are bonded together. A liquid crystal composition is then injected and filled into the cell gap partitioned by the substrate surface and the sealant, and after contact with the film surface, the injection holes are sealed. The above-mentioned liquid crystal composition is not particularly limited, and any composition containing at least one liquid crystal compound (liquid crystal molecule) can be used, and various liquid crystal compositions with positive or negative dielectric anisotropy can be used. In the following, a liquid crystal composition with positive dielectric anisotropy will also be called a positive-type liquid crystal, and a liquid crystal composition with negative dielectric anisotropy will also be called a negative-type liquid crystal. The above liquid crystal composition may contain liquid crystal compounds having a fluorine atom, a hydroxyl group, an amino group, a fluorine atom-containing group (e.g., a trifluoromethyl group), a cyano group, an alkyl group, an alkoxy group, an alkenyl group, an isothiocyanate group, a heterocycle, a cycloalkane, a cycloalkene, a steroid skeleton, a benzene ring, or a naphthalene ring, and may also contain compounds having two or more rigid sites (mesogenic skeletons) that exhibit liquid crystallinity within the molecule (for example, a bimesogenic compound in which two rigid biphenyl structures or terphenyl structures are linked by alkyl groups). The liquid crystal composition may be a liquid crystal composition exhibiting a nematic phase, a liquid crystal composition exhibiting a smectic phase, or a liquid crystal composition exhibiting a cholesteric phase. Furthermore, the above liquid crystal composition may contain additional additives from the viewpoint of improving liquid crystal alignment. Examples of such additives include photopolymerizable monomers such as compounds having polymerizable groups; optically active compounds (e.g., S-811 manufactured by Merck KGaA); antioxidants; ultraviolet absorbers; dyes; defoamers; polymerization initiators; or polymerization inhibitors. Examples of positive-type LCDs include the Merck ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, or MLC-7081. Examples of negative-type liquid crystal displays include Merck's MLC-6608, MLC-6609, MLC-6610, MLC-6882, MLC-6886, MLC-7026, MLC-7026-000, MLC-7026-100, and MLC-7029. In addition, in PSA mode, Merck's MLC-3023 is an example of a liquid crystal containing a polymerizable compound.

[0075] The second method is called the ODF (One Drop Fill) method. In this method, a UV-curable sealant is applied to a predetermined location on one of two substrates on which a liquid crystal alignment film has been formed, and then liquid crystal composition is dropped onto several predetermined locations on the surface of the liquid crystal alignment film. The other substrate is then bonded together so that the liquid crystal alignment films face each other, and the liquid crystal composition is spread across the entire surface of the substrate and brought into contact with the film surface. Next, the entire surface of the substrate is irradiated with UV light to cure the sealant.

[0076] In either method, it is desirable to further remove the flow orientation during liquid crystal filling by heating the liquid crystal composition to a temperature at which it forms an isotropic phase, and then slowly cooling it to room temperature. (3-2) When manufacturing a liquid crystal display element using the PSA method The procedure is the same as in (3-1) above, except that a liquid crystal composition containing a polymerizable compound is injected or dropped. Examples of polymerizable compounds include compounds having a mesogenic structure and two or more photopolymerizable or thermally polymerizable groups. Examples of mesogenic structures include structures in which two or more aromatic or aliphatic groups are linked, such as biphenyl structures, terphenyl structures, naphthalene rings, groups obtained by removing two hydroxyl groups from bisphenol A, or fluorine atom-containing structures in which some of the hydrogen atoms in these structures are replaced with fluorine atoms. Specific examples of compounds include 4,4'-dimethacryloxybiphenyl or 3-fluoro-1,1'-biphenyl-4,4'-diyldimethacrylate. (3-3) When a coating film is formed on a substrate using a liquid crystal alignment agent containing a polymerizable compound (SC-PVA method) A method may be adopted in which the liquid crystal display element is manufactured by following the same procedure as in (3-1) above, followed by a step of irradiating with ultraviolet light as described later. According to this method, a liquid crystal display element with excellent response speed can be obtained with a small amount of light irradiation, similar to the case in which the PSA method liquid crystal display element is manufactured. The compound having polymerizable groups may be the compound having polymerizable groups described above, and its content is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, per 100 parts by mass of all polymer components. Furthermore, the polymerizable groups may be present in the polymer used as a liquid crystal alignment agent, and examples of such polymers include polymers obtained by using a diamine component containing a diamine having the above-mentioned photopolymerizable groups at its terminals in the reaction. (4) Process of irradiating the liquid crystal cell with light The liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates obtained in (3-2) or (3-3) above. The applied voltage can be, for example, 5 to 50 V DC or AC. As the irradiated light, ultraviolet light and visible light including wavelengths of 150 to 800 nm can be used, but ultraviolet light including wavelengths of 300 to 400 nm is preferred. As the light source for the irradiation light, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, or an excimer laser can be used. The amount of light irradiated is preferably 1,000 to 200,000 J / m 2 More preferably, 1,000 to 100,000 J / m 2 That is the case.

[0077] A liquid crystal display element can then be obtained by laminating a polarizing plate onto the outer surface of the liquid crystal cell. Examples of polarizing plates that can be laminated onto the outer surface of the liquid crystal cell include a polarizing plate made by sandwiching a polarizing film called an "H film," which is made by stretching and oriented polyvinyl alcohol while absorbing iodine, between cellulose acetate protective films, or a polarizing plate made of the H film itself.

[0078] The liquid crystal display element of the present invention can be effectively applied to various devices, for example, it can be used in various display devices such as watches, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, liquid crystal televisions, and information displays. [Examples]

[0079] The present invention will be described in further detail below based on the examples, but the present invention is not limited in any way by these examples. The abbreviations of the compounds used and the methods for measuring each of their physical properties are as follows. (solvent) NMP:N-methyl-2-pyrrolidone BCS: Ethylene glycol monobutyl ether Cyrene: (1S,5R)-6,8-dioxabicyclo[3.2.1]octan-4-one (corresponding to compound (a))

[0080] [ka]

[0081] (Tetracarboxylic acid dianhydride) CA-1 to CA-2: Compounds represented by the following formulas (CA-1) to (CA-2), respectively.

[0082] [ka]

[0083] (Diamine) DA-1 to DA-2: Compounds represented by the following formulas (DA-1) to (DA-2), respectively.

[0084] [ka]

[0085] <Measuring molecular weight> The following measurements were performed using a room-temperature GPC (gel permeation chromatography) apparatus, and Mn and Mw were calculated as equivalent values ​​for polyethylene glycol and polyethylene oxide. GPC apparatus: SSC-7200 (Senshu Scientific Co., Ltd.), Columns: GPC KD-803 and GPC KD-805 (Showa Denko Co., Ltd.) in series, Column temperature: 50°C, Eluent: N,N-dimethylformamide (additives: lithium bromide monohydrate (LiBr·H2O) 30 mmol / L, anhydrous crystalline phosphoric acid (o-phosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 mL / L), Flow rate: 1.0 mL / min Standard samples for calibration curve creation: TSK standard polyethylene oxide (molecular weight: approximately 900,000, 150,000, 100,000, and 30,000) (manufactured by Tosoh Corporation) and polyethylene glycol (molecular weight: approximately 12,000, 4,000, and 1,000) (manufactured by Polymer Laboratory Co., Ltd.).

[0086] <Measurement of Imidification Rate> 20 mg of polyimide powder was placed in an NMR sample tube (NMR sampling tube standard, φ5 (manufactured by Kusano Science Co., Ltd.)), 1.0 mL of deuterated dimethyl sulfoxide ([D6]-DMSO, 0.05% tetramethylsilane (TMS) mixture) was added, and the powder was completely dissolved by sonication. The proton NMR of this solution was measured at 500 MHz using a Fourier transform superconducting nuclear magnetic resonance spectrometer (FT-NMR) "AVANCE III" (manufactured by BRUKER).

[0087] The (chemical) imidation rate was determined by using the following formula, with a reference proton derived from a structure that does not change before and after imidation, and the sum of the peak values ​​of this proton and the sum of the proton peaks derived from the NH group of the amic acid that appears around 9.5-10.0 ppm. In the following formula, x represents the sum of the proton peaks derived from the NH group of the amic acid, y represents the sum of the peak values ​​of the reference proton, and α represents the ratio of the number of reference protons to one proton of the NH group of the amic acid in the case of polyamic acid (imidation rate of 0%).

[0088] Imidization rate (%) = (1 - α·x / y) × 100

[0089] [Synthesis of polymers] <Synthesis Example 1> In a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, DA-1 (5.09 g, 11.7 mmol), DA-2 (4.15 g, 27.3 mmol), CA-2 (7.32 g, 29.3 mmol), and NMP (66.2 g) were added, and the mixture was stirred at 80°C for 3 hours while supplying nitrogen. After cooling to room temperature, CA-1 (1.87 g, 9.54 mmol) and NMP (7.49 g) were added, and the mixture was stirred at 40°C for 18 hours to obtain a polyamic acid solution. To the polyamic acid solution (50.0 g) obtained above, NMP (103 g), acetic anhydride (10.8 g), and pyridine (3.34 g) were added and stirred at room temperature for 30 minutes, then reacted at 80°C for 5 hours. This reaction solution was added to methanol (587 g), and the resulting precipitate was filtered off. This precipitate was washed with methanol and dried under reduced pressure at 60°C to obtain polyimide (SPI-1) powder. The imidization rate of this polyimide powder was 81%, with Mn being 12,502 and Mw being 36,348.

[0090] [Preparation of liquid crystal alignment agent] <Example 1> 2.00 g of polyimide (SPI-1) powder was mixed with 8.00 g of NMP and stirred at 70°C for 15 hours to dissolve, obtaining a polyimide solution. Using the above polyimide solution, it was diluted with cyrene and BCS, and stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (AL-1) with a mass ratio of polymer solids to each solvent (polymer solids:cyrene:NMP:BCS) of 6:30:24:40.

[0091] <Example 2> Cyrene (11.3g) was added to polyimide (SPI-1) powder (2.00g), and the mixture was stirred at 70°C for 15 hours to dissolve it and obtain a polyimide solution. Using the above polyimide solution, dilution with Cyrene and BCS was performed, and the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (AL-2) with a mass ratio of polymer solids to each solvent (polymer solids:Cyrene:BCS) of 6:54:40.

[0092] <Comparative Example 1> 2.00 g of polyimide (SPI-1) powder was mixed with 11.3 g of NMP and stirred at 70°C for 15 hours to dissolve, obtaining a polyimide solution. Using the above polyimide solution, it was diluted with NMP and BCS, and stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (AL-3) with a mass ratio of polymer solids to each solvent (polymer solids:NMP:BCS) of 6:54:40.

[0093] Table 1 shows the specifications of each liquid crystal alignment agent prepared above.

[0094] [Table 1]

[0095] [Evaluation of printability] The liquid crystal alignment agents AL-1 to AL-3 obtained in Examples 1 to 2 and Comparative Example 1 were filtered through a 1.0 μm pore size filter, and then flexographic printing was performed on a washed Cr-deposited substrate using an alignment film printing machine ("Angstromer" manufactured by Nippon Printing Co., Ltd.) to conduct printability tests. Specifically, approximately 1.0 mL of liquid crystal alignment agent was dropped onto an anilox roll, and after five empty runs, printing was performed on one Cr-deposited substrate (100 mm x 100 mm, 1.0 mm thick) with a print setting of 80 mm x 80 mm and a print pressure of 0.2 mm. After printing, the substrate was left on a 70°C hot plate for 90 seconds to pre-dry the coating, and the film condition was observed. Film thickness unevenness at the edges was observed visually and with an optical microscope (Nikon "ECLIPSE ME600") at 50x magnification. As an evaluation criterion, the area with the largest film thickness unevenness at the edge of the printed coating was selected, and if the width of this largest film thickness unevenness was 1.5 mm or less, it was marked as "○", and if it was wider, it was marked as "×". More specifically, in a polyimide film printed on a Cr-deposited substrate (Figure 1), the area with the largest film thickness variation (dotted line in Figure 1) was selected, and the length of A in Figure 2 of the polyimide film image obtained by observing it with an optical microscope at 50x magnification was measured. This length of A corresponds to the width of the film thickness variation mentioned above. The results are shown in Table 2.

[0096] [Fabrication of liquid crystal cells] A liquid crystal cell was fabricated using the liquid crystal alignment agent obtained above, following the procedure shown below. The liquid crystal alignment agent was spin-coated onto a glass substrate (3 cm wide x 4 cm long) with ITO electrodes, dried on a hot plate at 70°C for 90 seconds, and then fired in an infrared heating furnace at 230°C for 20 minutes to form a liquid crystal alignment film with a thickness of 100 nm. Two substrates with this liquid crystal alignment film were prepared. A 4 μm diameter bead spacer (JGC Catalysts & Chemicals, brass ball, SW-D1) was applied to the liquid crystal alignment film on one of the substrates, and a thermosetting sealant (Mitsui Chemicals, XN-1500T) was printed around the periphery, leaving a liquid crystal injection port. Next, the other substrate was bonded to the first substrate with the side of the liquid crystal alignment film facing inward, and the sealant was cured to create an empty cell. Liquid crystal MLC-3023 (Merck) was injected into this empty cell by a reduced-pressure injection method to fabricate a liquid crystal cell. Next, with a DC voltage of 15V applied to the liquid crystal cell, ultraviolet light with a wavelength of 325nm or less, passed through a cut filter, was shone from the outside of the liquid crystal cell at a rate of 10J / cm². 2The cells were irradiated. The ultraviolet irradiance was measured using an ultraviolet irradiator / light meter UV-M03A manufactured by Oak Manufacturing Co., Ltd. Subsequently, in order to deactivate any unreacted polymerizable compounds remaining in the liquid crystal cells, ultraviolet light (UV lamp: FLR40SUV32 / A-1) was irradiated for 30 minutes using a UV-FL irradiation device manufactured by Toshiba Lighting & Technology Corporation without applying any voltage.

[0097] [Evaluation of liquid crystal alignment] The liquid crystal alignment of the liquid crystal display elements was observed using a polarizing microscope (Nikon "ECLIPSE E600WPOL") to confirm whether the liquid crystals were oriented perpendicularly. The evaluation criteria were as follows: "○" indicated no defects due to liquid crystal flow or bright spots due to alignment defects, while "×" indicated the presence of defects due to liquid crystal flow or bright spots due to alignment defects. The evaluation results are shown in Table 2.

[0098] [Table 2]

[0099] As shown in Table 2, Examples 1 and 2, which used a liquid crystal alignment agent containing compound (a) represented by the above formula (A), showed better printability and no problems with liquid crystal alignment characteristics compared to Comparative Example 1, which used a liquid crystal alignment agent that did not contain compound (a).

[0100] Furthermore, the entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2021-142711, filed on September 1, 2021, are incorporated herein by reference as disclosure of the specification of the present invention.

Claims

1. A liquid crystal alignment agent comprising at least one polymer (P) selected from the group consisting of a polyimide precursor and a polyimide which is an imidized product of the polyimide precursor, and a solvent component containing a compound (a) represented by the following formula (A). 【Chemistry 1】

2. The liquid crystal alignment agent according to claim 1, wherein the content of compound (a) is 5% by mass or more relative to the total amount of solvent components contained in the liquid crystal alignment agent.

3. The liquid crystal alignment agent according to claim 1 or 2, wherein the polymer (P) is a polymer obtained by a polymerization reaction between a diamine component and a tetracarboxylic acid component containing a tetracarboxylic dianhydride.

4. The liquid crystal aligning agent according to any one of claims 1 to 3, wherein the polymer (P) is obtained by a polymerization reaction between a diamine component and a tetracarboxylic acid component containing a tetracarboxylic acid dianhydride, and the tetracarboxylic acid dianhydride is at least one compound selected from acyclic aliphatic tetracarboxylic acid dianhydride, alicyclic tetracarboxylic acid dianhydride, and aromatic tetracarboxylic acid dianhydride.

5. The liquid crystal alignment agent according to claim 3 or 4, wherein the tetracarboxylic acid component comprises a tetracarboxylic dianhydride having at least one substructure selected from the group consisting of a benzene ring, a cyclobutane ring structure, a cyclopentane ring structure, and a cyclohexane ring structure.

6. The aforementioned solvent components may further include γ-valerolactone, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 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, N,N-dimethylformamide, N,N-diethylformamide, N,N- A liquid crystal alignment agent according to any one of claims 1 to 5, comprising a solvent selected from the group consisting of dimethylacetamide, N,N-diethylacetamide, N,N-dimethylpropionamide, N,N-dimethylisobutylamide (N,N,2-trimethylpropionamide), N,N-diethylpropionamide, N,N-dipropylacetamide, N,N-diisopropylacetamide, N,N-dibutylacetamide, N,N-dimethyllactamide, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, tetramethylurea, hexamethylphospholtriamide, cyclohexanone, and cyclopentanone.

7. The aforementioned solvent components may further include 4-hydroxy-4-methyl-2-pentanone, n-butyl acetate, propylene glycol monoethyl ether acetate, cyclohexyl acetate, 4-methyl-2-pentyl acetate, n-butyl lactate, isoamyl lactate (isopentyl lactate), methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol n-propyl ether, ethylene glycol isopropyl ether, ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, and propyl A liquid crystal alignment agent according to any one of claims 1 to 6, comprising a solvent selected from the group consisting of ethylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, diisobutylcarbinol, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, ethylene carbonate, and propylene carbonate.

8. The liquid crystal alignment agent according to any one of claims 3 to 5, wherein the diamine component contains an aromatic diamine (d) represented by "A-X-J". (A represents a monovalent group in which two primary amino groups are bonded to an aromatic group. X is a single bond, -(CH ２ ) ａ -(a is an integer from 1 to 15), -CONH-, -NHCO-, -CO-N(CH ３ )-, -NH-, -O-, -COO-, -OCO- or -(A ０ ) ｍ０ -( (CH ２ ) ａ１ -A １ ) ｍ１ -(a1 is an integer from 1 to 15, and A ０、 A １ each independently represents an oxygen atom or -COO-, m0 is an integer of 0 or 1, and m1 is an integer from 1 to 2.) If m1 is 2, then multiple a1 and A １ Each of these has its own independent definition. J represents a monovalent organic group having at least one group selected from the group consisting of alicyclic hydrocarbon groups having 4 to 40 carbon atoms and aromatic hydrocarbon groups having 6 to 40 carbon atoms. However, at least one of the hydrogen atoms in the above alicyclic hydrocarbon group and aromatic hydrocarbon group is substituted by a substituent (v) which is one of the following: a halogen atom, a halogen atom-containing alkyl group, a halogen atom-containing alkoxy group, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, and an alkenyl group having 3 to 10 carbon atoms. Furthermore, any carbon-carbon single bond in these substituents (v) (except for halogen atoms) may be interrupted by -O-. In addition, J may further have at least one group selected from the group consisting of alicyclic hydrocarbon groups and aromatic hydrocarbon groups that are unsubstituted or substituted with substituents other than the substituents (v) described above.

9. The liquid crystal alignment agent according to claim 8, wherein the aromatic diamine (d) described above has the following structure (S1) as the group "-X-J". 【Chemistry 2】 (X １ is a single bond, -(CH ２ ) ａ - (a is an integer from 1 to 15), -CONH-, -CO-N(CH ３ )-, -NH-, -O-, -COO-, or -(A ０ ) ｍ０ - ((CH ２ ) ａ１ -A １ ) ｍ１ - (a1 is an integer from 1 to 15, A ０、 A １ Each of these independently represents an oxygen atom or -COO-, where m0 is an integer of 0 or 1, and m1 is an integer of 1 to 2. If m1 is 2, then multiple a1 and A １ Each of these has its own independent definition. G １ This represents a divalent cyclic group selected from a phenylene group and a cyclohexylene group. Any hydrogen atom on the cyclic group may be substituted with a C1-C3 alkyl group, a C1-C3 alkoxy group, a C1-C3 fluorine-containing alkyl group, a C1-C3 fluorine-containing alkoxy group, or a fluorine atom. m is an integer from 1 to 4. If m is 2 or greater, multiple X １ G １ Each of these has its own independent definition. R １ (This represents a fluorine atom, a fluorine atom-containing alkyl group having 1 to 10 carbon atoms, a fluorine atom-containing alkoxy group having 1 to 10 carbon atoms, an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, or an alkoxyalkyl group having 3 to 10 carbon atoms.)

10. The liquid crystal alignment agent according to claim 8 or 9, wherein the aromatic diamine (d) is a diamine represented by the following formulas (d-1) to (d-2). 【Transformation 3】 (X and J are defined as in claim 8. In formula (d-2), the two X and J may be the same or different from each other.)

11. A liquid crystal alignment agent according to any one of claims 1 to 10, used for forming a horizontally or vertically aligned liquid crystal alignment film, a liquid crystal alignment film for a phase difference film, a liquid crystal alignment film for a scanning antenna or a liquid crystal array antenna, or a liquid crystal alignment film for a transmission-scattering type liquid crystal dimming element.

12. A liquid crystal alignment film obtained from a liquid crystal alignment agent according to any one of claims 1 to 11.

13. A liquid crystal display element comprising the liquid crystal alignment film described in claim 12.

14. A method for manufacturing a liquid crystal display element, comprising performing the following steps (1) to (3) in this order. Step (1): A step of applying the liquid crystal alignment agent according to any one of claims 1 to 11 onto at least one of a pair of substrates having a conductive film to form a coating film. Step (2): A step of firing the coating film. Step (3): A step to produce a liquid crystal cell by forming a liquid crystal layer between the pair of substrates.

15. A method for manufacturing a liquid crystal display element according to claim 14, further comprising performing the following step (4) after steps (1) to (3). Step (4): Step of irradiating the liquid crystal cell with light.

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