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

Abstract

A liquid crystal aligning agent that enables obtaining a liquid crystal aligned film with high film strength and suppressed AC afterimage, a liquid crystal aligned film obtained from said liquid crystal aligning agent, and a liquid crystal display element that uses this are provided.　This liquid crystal aligning agent contains the component (A) below and the compound (B) represented by formula (1). Component (A) is a polymer component that includes a polymer (A) selected from the group comprising: a polyimide precursor obtained by a polymerization reaction brought about between a diamine component and a tetracarboxylic acid derivative component containing at least one compound selected from the group comprising a tetracarboxylic dianhydride and a derivative thereof; and a polyimide which is an imide compound of said polyimide precursor. [Chemical formula 1] (1) (the definitions of the symbols are as described in the detailed description.) [Chemical formula 2] (EG) (the definitions of the symbols are as described in the detailed description.)

Description

[Technical Field]

[0001] This invention relates to liquid crystal alignment agents, liquid crystal alignment films, liquid crystal display elements, and compounds that can be used in these. [Background technology]

[0002] Liquid crystal display devices have long been widely used as display units in personal computers, smartphones, mobile phones, television receivers, and other devices. A liquid crystal display device includes, for example, a liquid crystal layer sandwiched between an element substrate and a color filter substrate, pixel electrodes and a common electrode that apply an electric field to the liquid crystal layer, an alignment film that controls the orientation of the liquid crystal molecules in the liquid crystal layer, and thin-film transistors (TFTs) that switch the electrical signals supplied to the pixel electrodes. Known methods for driving liquid crystal molecules include vertical electric field methods such as the TN (Twisted Nematic) method and the VA (Vertical Alignment) method, and horizontal electric field methods such as the IPS (In-Plane Switching) method and the FFS (Fringe Field Switching) method.

[0003] Currently, the most widely used liquid crystal alignment films in industry are manufactured by a so-called rubbing process, in which the surface of a film made of a polymer, such as polyamic acid and / or polyimide (an imidized version thereof), formed on an electrode substrate, is rubbed in one direction with a cloth such as cotton, nylon, or polyester. Rubbing is a simple and highly productive method that is useful in industry. On the other hand, with the increasing performance, resolution, and size of liquid crystal display elements, photo-alignment methods, which impart liquid crystal alignment ability by irradiating with polarized radiation, have been developed as an alternative alignment method to rubbing. Photo-alignment methods utilizing photoisomerization reactions, photocrosslinking reactions, and photodecomposition reactions have been proposed (see, for example, Non-Patent Document 1 and Patent Document 1).

[0004] In recent years, large-screen and high-definition liquid crystal TVs have become the mainstream, and the popularity of small display terminals such as smartphones, tablet PCs, and car navigation systems has been increasing. As a reliability test for liquid crystal display elements used in mobile applications such as smartphones and in-vehicle applications such as car navigation systems, a panel vibration test may be conducted. In this vibration test, it is required that no defects such as bright spots occur. In order to obtain a liquid crystal display element that does not develop defects after the vibration test, for example, a method of enhancing the mechanical strength of the liquid crystal alignment film can be considered. As a method of improving the mechanical strength, particularly the film strength, of the liquid crystal alignment film, a method of adding a crosslinking agent to the liquid crystal aligning agent can be mentioned. In addition, in the IPS mode and the FFS mode, the stability of liquid crystal alignment is also important. If the alignment stability is low, when the liquid crystal is driven for a long time, the liquid crystal cannot return to its initial state, which causes a decrease in contrast and image sticking (hereinafter referred to as AC residual image). As a means of solving these problems, a liquid crystal aligning agent containing a specific polyimide component and a specific hydroxyalkylamide compound has been proposed (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Non-Patent Documents

[0006]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, with the increasing high definition of liquid crystal display elements, the level for the above requirements has become higher, and there is a need for a liquid crystal aligning agent that can satisfy all of these requirements at a high level.

[0008] From the above, an object of the present invention is to provide a liquid crystal aligning agent capable of obtaining a liquid crystal alignment film having high film strength and suppressing AC afterimages, a liquid crystal alignment film obtained from the liquid crystal aligning agent, and a liquid crystal display element using the same.

Means for Solving the Problems

[0009] As a result of intensive studies to achieve the above problems, the present inventor has found that a liquid crystal aligning agent containing a specific compound and a polymer component as constituent components is extremely effective for achieving the above object, and has completed the present invention.

[0010] The present invention includes the following aspects. A liquid crystal aligning agent containing the following component (A) and a compound (B) represented by the following formula (1). (Component (A): A polymer component containing a polymer (A) selected from the group consisting of a polyimide precursor obtained by subjecting a tetracarboxylic acid derivative component containing at least one compound selected from the group consisting of tetracarboxylic dianhydrides and their derivatives and a diamine component to a polymerization reaction, and a polyimide which is an imidized product of the polyimide precursor.

Chemical formula

Chemical formula

Effects of the Invention

[0011] According to the present invention, it is possible to provide a liquid crystal alignment agent that can produce a liquid crystal alignment film with high film strength and suppressed AC afterimage, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element using the same. The mechanism by which the above effects are obtained by the present invention is not entirely clear, but the following is considered to be one of the contributing factors. Specifically, it is thought that the above effects are obtained because the introduction of a specific alkylene glycol chain into the crosslinking agent structure added to the liquid crystal alignment agent provides appropriate flexibility to the crosslinking structure of the formed liquid crystal alignment film. [Modes for carrying out the invention]

[0012] The following will describe in detail a liquid crystal alignment agent containing specific components, a liquid crystal alignment film formed using the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film. However, the description of the constituent elements described below is merely an example of one embodiment of the present invention and is not limited to these contents. In the following explanation, "halogen atoms" include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc. "Boc" represents a tert-butoxycarbonyl group, and "*" indicates a bond position.

[0013] <Polymer (A)> The liquid crystal alignment agent of the present invention contains component (A) above. The polymer component refers to a component made of polymers, and may consist of one type of polymer or multiple types of polymers. Furthermore, polymer (A) may be one type or two or more types. The polymer (A) contained in component (A) above is a polymer selected from the group consisting of a polyimide precursor and a polyimide which is an imidized product of the polyimide precursor, obtained by polymerizing a tetracarboxylic acid derivative component containing at least one compound selected from the group consisting of tetracarboxylic dianhydride and its derivatives with a diamine component. (Hereinafter also referred to as polyimide polymer (A)). The polyimide precursor in polyimide polymer (A) is obtained by polymerizing a tetracarboxylic acid derivative component and a diamine component. The tetracarboxylic acid derivative component includes at least one compound selected from the group consisting of tetracarboxylic dianhydrides and their derivatives (hereinafter, these are collectively referred to as tetracarboxylic dianhydride compounds). Examples of the polyimide precursors mentioned above include polyamic acid and polyamic acid esters. Examples of the derivatives of the tetracarboxylic dianhydride mentioned above include tetracarboxylic dihalides, tetracarboxylic dialkyl esters, or tetracarboxylic dialkyl ester dihalides.

[0014] <<Polyimide polymer (A)>> When the above polyimide polymer (A) is a polyamic acid, the polyimide polymer (A) can be obtained, for example, by polymerizing (polycondensing) a tetracarboxylic acid derivative component containing a tetracarboxylic acid dianhydride with a diamine component. Furthermore, the polyimide in the above polyimide polymer (A) can be obtained by imidizing the above polyamic acid. Moreover, when the above polyimide polymer (A) is a polyamic acid ester, it can be obtained by the method described later, and the polyimide can be obtained by imidizing the polyamic acid ester.

[0015] <<<Tetracarboxylic acid dianhydride compounds>>> The above-mentioned tetracarboxylic dianhydride compounds include, for example, aromatic tetracarboxylic dianhydrides, acyclic aliphatic tetracarboxylic dianhydrides, or alicyclic tetracarboxylic dianhydrides, or derivatives thereof. Here, aromatic tetracarboxylic dianhydrides are acidic dianhydrides obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to an 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 a chain-like hydrocarbon structure; they may also have an alicyclic structure or an aromatic ring structure in part.

[0016] The above aromatic tetracarboxylic dianhydrides, or derivatives thereof, are preferably tetracarboxylic dianhydrides or derivatives thereof having at least one substructure selected from the group consisting of a benzene ring structure, a naphthalene ring structure, and an aromatic heterocyclic structure, from the viewpoint of enhancing liquid crystal orientation.

[0017] Furthermore, 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 the aromatic ring. Furthermore, it is not necessary for the structure to consist solely of alicyclic structures; it may also contain chain-like hydrocarbon structures or aromatic ring structures as part of it.

[0018] The above acyclic aliphatic or alicyclic tetracarboxylic dianhydrides, or derivatives thereof, are preferably tetracarboxylic dianhydrides or derivatives thereof having at least one substructure selected from the group consisting of a cyclobutane ring structure, a cyclopentane ring structure, and a cyclohexane ring structure, from the viewpoint of enhancing liquid crystal orientation.

[0019] Among the above aromatic tetracarboxylic dianhydrides, acyclic aliphatic tetracarboxylic dianhydrides, or alicyclic tetracarboxylic dianhydrides, tetracarboxylic dianhydrides represented by the following formula (2) are preferred. [ka] (In equation (2), X represents a structure selected from the group consisting of the following equations (x-1) to (x-17) and (xr-1) to (xr-2).) [ka] [ka] (In formula (x-1), R 1 ~R 4Each of these independently represents a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C2-C6 alkenyl group, a C2-C6 alkynyl group, a C1-C6 monovalent organic group containing a fluorine atom, a C1-C6 alkoxy group, a C2-C6 alkoxyalkyl group, a C2-C6 alkyloxycarbonyl group, or a phenyl group. In formula (x-7), R 5 and R 6 Each of these independently represents a hydrogen atom or a methyl group. In formulas (xr-1) to (xr-2), j and k are integers of 0 or 1, and A1 and A2 independently represent a single bond, -O-, -CO-, -COO-, a phenylene group, a sulfonyl group, or an amide group. The multiple A2s in formula (xr-2) may be the same or different. *1 is a bond attached to one acid anhydride group, and *2 is a bond attached to the other acid anhydride group.

[0020] A preferred specific example of the tetracarboxylic dianhydride represented by formula (2) above is one in which X is selected from (x-1) to (x-8), (x-10) to (x-11), and (xr-1) to (xr-2).

[0021] The above equation (x-1) is preferably selected from the group consisting of the following equations (x1-1) to (x1-6). [ka] (*1 is a bond that attaches to one acid anhydride group, and *2 is a bond that attaches to the other acid anhydride group.)

[0022] Preferred specific examples of the above equations (xr-1) and (xr-2) include the following equations (xr-3) to (xr-18). [ka] [ka] (In the above formula, * represents a bond that connects to the acid anhydride group.)

[0023] When producing the polyimide polymer (A), the amount of tetracarboxylic dianhydride represented by formula (2) or its derivative used is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 20 mol% or more, based on 1 mole of the total tetracarboxylic derivative component reacted with the diamine component.

[0024] <<<Diamine component>>> The diamine component used in the production of the polyimide precursor is not particularly limited, but a diamine component containing a diamine represented by the following formula (3) is preferred. [ka] (In formula (3), Ar1 and Ar 1’ Each independently represents a benzene ring, a biphenyl structure, or a naphthalene ring, and one or more hydrogen atoms on the benzene ring, the biphenyl structure, or the naphthalene ring may be substituted with a monovalent group. L1 and L 1’ Each of these independently represents a single bond, -O-, -C(=O)-, -C(=O)-O-, or -OC(=O)-. A represents -CH2-, an alkylene group having 2 to 12 carbon atoms, or a divalent organic group formed by the insertion of at least one of the groups -O-, -C(=O)-O-, and -OC(=O)- between the carbon-carbon bonds of the alkylene group. Any hydrogen atom in A may be substituted with a halogen atom.

[0025] In the above formula (3), Ar1 and Ar 1’ Each of these independently represents a benzene ring, a biphenyl structure, or a naphthalene ring. One or more hydrogen atoms on the benzene ring, the biphenyl structure, or the naphthalene ring may be substituted with a monovalent group, and examples of such monovalent groups include halogen atoms, C1-C3 alkyl groups, C2-C3 alkenyl groups, C1-C3 alkoxy groups, C1-C3 fluoroalkyl groups, C2-C3 fluoroalkenyl groups, C1-C3 fluoroalkoxy groups, C2-C3 alkyloxycarbonyl groups, cyano groups, nitro groups, and the like.

[0026] In Ar1 and Ar of the above formula (3), 1’ the bonding position of the amino group to the benzene ring and L1 or L 1’ is preferably the 1,4-position or 1,3-position, more preferably the 1,4-position. The bonding position of the amino group to the biphenyl structure and L1 or L 1’ is preferably the 4,4'-position or 3,3'-position, more preferably the 4,4'-position. The bonding position of the amino group to the naphthalene ring and L1 or L 1’ is preferably the 1,5-position or 2,6-position, more preferably the 2,6-position. Preferred specific examples of Ar1 and Ar 1’ include a benzene ring, a biphenyl structure, and a naphthalene ring.

[0027] A in the above formula (3) represents -CH2-, an alkylene group having 2 to 12 carbon atoms, or a divalent organic group in which at least one of -O-, -C(=O)-O-, and -O-C(=O)- is inserted between carbon-carbon bonds of the alkylene group. Any hydrogen atom of A may be substituted with a halogen atom. The alkylene group having 2 to 12 carbon atoms may be linear or branched, but is preferably linear. Preferred specific examples of A include linear alkylene groups having 2 to 6 carbon atoms. -O-, -C(=O)-O-, and -O-C(=O)- inserted into the divalent organic group may each be one or a plurality.

[0028] Preferred specific examples of the group -L1-A-L 1’ - in the above formula (3) are given below. -(CH2) n - -O-(CH2) n - -O-(CH2) n -O- -C(=O)-(CH2) n -C(=O)- -O-C(=O)-(CH2) n -O- -OC(=O)-(CH2) n -OC(=O)-, -OC(=O)-(CH2) n -C(=O)-O-, -C(=O)-O-(CH2) n -OC(=O)-, -(CH2) m1 -O-(CH2) n’ -O-(CH2) m2 -, -(CH2) m1 -OC(=O)-(CH2) n’ -C(=O)-O-(CH2) m2 -, -(CH2) m1 -C(=O)-O-(CH2) n’ -OC(=O)-(CH2) m2 -

[0029] The above base-L1-AL 1’ In a preferred example of -, n is an integer between 1 and 12, more preferably an integer between 2 and 12, and even more preferably an integer between 2 and 6. The sum of m1, m2, and n' is an integer between 3 and 12, preferably between 6 and 12. m1 and m2 are preferably integers between 1 and 4, and more preferably between 2 and 4, respectively. n' is preferably an integer between 1 and 6, more preferably between 2 and 6, and even more preferably between 2 and 4.

[0030] The proportion of the diamine represented by formula (3) is preferably 1 mol% or more, more preferably 10 mol% or more, and even more preferably 20 mol% or more, per mole of the diamine component.

[0031] The polyimide polymer (A) may contain other diamines besides the diamine described above. Examples of other diamines are given below, but the present invention is not limited to these. When other diamines are used in combination with the diamine represented by formula (3) above, the amount of the diamine represented by formula (3) relative to the diamine component is preferably 90 mol% or less, and more preferably 80 mol% or less. Examples of other diamines are given below, but the present invention is not limited to these. The above other diamines may be used individually or in combination of two or more.

[0032] p-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, m-phenylenediamine, 2,4-dimethyl-m-phenylenediamine, 1,4-diamino-2,5-dimethoxybenzene, 2,5-diaminotoluene, 2,6-diaminotoluene, 4-aminobenzylamine, 2-(4-aminophenyl)ethylamine, and semi-aromatic diamines having a secondary amino group and a primary amino group (preferably 4-(2-(methylamino)ethyl)aniline). (Here, a semi-aromatic diamine refers to a diamine in which one amino group is bonded to an aromatic ring and the other amino group is not bonded to an aromatic ring.)), 4-(2-aminoethyl)aniline, 2-(6-amino-2-naphthyl)ethylamine, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 3-trifluoromethyl-4,4'-diaminobiphenyl, 2-trifluoromethyl-4,4'-diaminobiphenyl, 3-fluoro-4,4'-diaminobiphenyl, 2-fluoro-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 Diamines having a tetracarboxylic acid diimide structure, such as Nyl, 3,4'-diaminobiphenyl, 4,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'-diaminobiphenyl, 2,3'-diaminobiphenyl, 1,5-diaminonaphthalene, 1,6-diaminonaphthalene, 1,7-diaminonaphthalene, 2,6-diaminonaphthalene, 2,7-diaminonaphthalene; N,N'-bis(4-aminophenyl)-cyclobutane-(1,2,3,4)-tetracarboxylic acid diimide, N,N'-bis(4-aminophenyl)-1,3-dimethylcyclobutane-(1,2,3,4)-tetracarboxylic acid diimide, N,N'-bis(2,2'-bis(trifluoromethyl)-4'-amino-1,1'-biphenyl-4-yl)-cyclobutane-(1,2,3,4)-tetracarboxylic acid diimide;

[0033] 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; 4,4'-diaminoazobenzene, diaminotran, 4,4-diaminochalcone, or [4-[(E)-3-[[5-amino-2-[4- Diamines having photo-directing groups, such as aromatic diamines having a cinnamate structure, represented by 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-(4,4,4-trifluorobutoxy)benzoate; diamines having photopolymerizable groups at the terminal, such as 2-(2,4-diaminophenoxy)ethyl methacrylate or 2,4-diamino-N,N-diallylaniline; 1-(4-(2-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylpropanone, 2-(4-(2-hydroxy-2-methylpropanoyl)phenoxy)ethyl Diamines with radical polymerization initiator function, such as 3,5-diaminobenzoate; diamines with amide bonds, such as 4,4'-diaminobenzanilide; diamines with urea bonds, such as 1,3-bis(4-aminophenyl)urea; H2N-Y D -NH2(Y D Diamines having a thermally detachable group such as -N(D)- (where D represents a protecting group that is removed by heating and replaced by a hydrogen atom) within the molecule;

[0034] 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)diphenyl ether, 1,4-bis[4-(4-aminophenoxy)phenoxy]benzene, 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, 1,4-Bis(4-aminophenyl)benzene, 1,3-Bis(4-aminophenyl)benzene, 4,4'-Diaminobenzophenone, 1,4-Bis(4-aminobenzyl)benzene;2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N-[3-(1H-imidazole-1-yl)propyl]-3,5-diaminobenzamide, 4-[4-[(4-aminophenoxy)methyl]-4,5-dihydro-4-methyl-2-oxazolyl ]-Benzeneamine, 4-[4-[(4-aminophenoxy)methyl]-4,5-dihydro-2-oxazolyl]-benzeneamine, 1,4-bis(p-aminobenzyl)piperazine, 4,4'-[propane-1,3-diylbis(piperidine-1,4-diyl)]dianiline, 4-(4-aminophenoxycarbonyl)-1-(4-aminophenyl)piperidine, 2,5-bis(4-aminophenyl)pyrrole, 4,4'-(1-methyl-1H-pyrrole-2,5-diyl)bis[benzeneamine], 1,4-bis-(4-aminophenyl)-piperazine Radins, 2-N-(4-aminophenyl)pyridine-2,5-diamine, 2-N-(5-aminopyridine-2-yl)pyridine-2,5-diamine, 2-(4-aminophenyl)-5-aminobenzimidazole, 2-(4-aminophenyl)-6-aminobenzimidazole, 5-(1H-benzimidazole-2-yl)benzene-1,3-diamine, or heterocyclic diamines such as diamines represented by the following formulas (z-1) to (z-5), or 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl-N-methylamine, Diamines having a diphenylamine structure, such as N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine, or N,N'-bis(4-aminophenyl)-N,N'-dimethyl-1,4-benzenediamine, which have at least one nitrogen atom-containing structure selected from the group consisting of a heterocyclic ring containing a nitrogen atom and a secondary or tertiary amino group (excluding amino groups derived from -N(D)- (where D represents a protecting group that is eliminated by heating and replaced by a hydrogen atom));

[0035] 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 4,4'-diamino-3,3'-dihydroxybiphenyl; 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, 4,4'-diaminobiphenyl-3-carboxylic acid, 4,4'-diaminodiphenylmethane-3-carboxylic acid, 1,2-bis(4-aminophenyl)ethane-3-carboxylic acid, 4,4'-diaminobiphenyl-3,3'-dihydroxybiphenyl Diamines having a carboxyl group, such as rubonic 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, 4,4'-diaminodiphenyl ether-3,3'-dicarboxylic acid; 1-(4-aminophenyl)-1,3,3-trimethyl-1H-indan-5-amine, 1-(4-aminophenyl Diamines having a steroid skeleton such as cholestanyloxy-3,5-diaminobenzene, cholestanyloxy-3,5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestanyl 3,5-diaminobenzoate cholestanyl, 3,5-diaminobenzoate cholestanyl, 3,5-diaminobenzoate lanostanyl and 3,6-bis(4-aminobenzoyloxy)cholestane; diamines represented by the following formulas (V-1)~(V-2); 1,3-bis(3-amine Diamines having siloxane bonds, such as nopropyl)-tetramethyldisiloxane; acyclic aliphatic diamines such as metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, and hexamethylenediamine; alicyclic diamines such as 1,3-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, and 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 WO2018 / 117239. [ka] [ka] (In equation (V-1), m and n are integers from 0 to 3 (where 1 ≤ m + n ≤ 4), and j is an integer of 0 or 1, X 1 is, -(CH2) a -(a is an integer from 1 to 15), represents -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -CH2O-, -CH2-OCO-, -COO-, or -OCO-. 1 X 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. In formula (V-2), X 2 R represents -O-, -CH2O-, -CH2-OCO-, -COO-, or -OCO-, 2 m, n, X represent alkyl groups with 3 to 30 carbon atoms and fluorine-containing alkyl groups with 3 to 20 carbon atoms. 1 , and R 1 If two such entities exist, each independently has the above definition.

[0036] Furthermore, the D in the -N(D)- of the other diamines mentioned above is preferably a carbamate-based organic group such as a benzyloxycarbonyl group, a 9-fluorenylmethyloxycarbonyl group, an allyloxycarbonyl group, or Boc. Boc is particularly preferred from the viewpoint of efficient thermal elimination, elimination at relatively low temperatures, and emission as a harmless gas upon elimination.

[0037] Preferred examples of diamines having a thermally detachable group, as exemplified above as other diamines, include diamines selected from the following formulas (d-1) to (d-7). [ka] (In formulas (d-2), (d-6), and (d-7), R represents a hydrogen atom or Boc.)

[0038] When using a diamine having the above-mentioned thermally detachable group as the diamine component used in the production of a polyimide precursor, from the viewpoint of suitably obtaining the effects of the present invention, it is preferably 5 to 40 mol%, more preferably 5 to 35 mol%, and even more preferably 5 to 30 mol% per mole of the diamine component.

[0039] The polymer (A) may contain, from the viewpoint of reducing residual DC afterimages or improving electrical properties, at least one polymer (hereinafter also referred to as polyimide polymer (Q)) selected from the group consisting of a polyimide precursor obtained using a diamine component selected from the group consisting of a diamine having the above nitrogen atom-containing structure and a semi-aromatic diamine having a secondary amino group and a primary amino group, and an imidized product of the polyimide precursor. Examples of tetracarboxylic acid derivative components for obtaining the above-mentioned polyimide polymer (Q) include tetracarboxylic acid derivative components containing the above-mentioned tetracarboxylic acid dianhydride compounds. Among these, the tetracarboxylic acid dianhydride represented by formula (2) or its derivative is preferred. The amount of the tetracarboxylic acid dianhydride represented by formula (2) or its derivative used is preferably 10 mol% or more, and more preferably 20 mol% or more, based on 1 mole of the total tetracarboxylic acid derivative component reacted with the diamine component. As the diamine component for obtaining the above polyimide polymer (Q), the amount of diamine selected from the group consisting of diamines having the above nitrogen atom-containing structure and semi-aromatic diamines having a secondary amino group and a primary amino group is preferably 5 to 100 mol%, more preferably 10 to 95 mol%, and even more preferably 20 to 80 mol%, relative to the total amount of diamine component for obtaining polymer (Q). The diamine component for obtaining the above polyimide polymer (Q) may further contain diamines other than the above-mentioned diamine having a nitrogen atom-containing structure and semi-aromatic diamines having a secondary amino group and a primary amino group. A preferred specific example of the diamine is a diamine having at least one group selected from the group consisting of a urea bond, an amide bond, a carboxyl group, and a hydroxyl group in its molecule (hereinafter also referred to as diamine (c)). The amount of diamine (c) used is preferably 1 to 95 mol%, more preferably 5 to 90 mol%, and even more preferably 20 to 80 mol%, relative to the total amount of diamine components for obtaining polymer (Q).

[0040] Component (A) contained in the liquid crystal alignment agent of the present invention may be a mixture of the above-mentioned polyimide polymer (Q) and at least one polymer selected from the group consisting of a polyimide precursor obtained using a diamine component that does not contain a diamine having a nitrogen atom structure and a semi-aromatic diamine having a secondary amino group and a primary amino group, and an imidized product of the polyimide precursor (hereinafter also referred to as polyimide polymer (H)). As a diamine component for obtaining the above polyimide polymer (H), it may contain at least one diamine selected from the group consisting of the diamine represented by formula (3) above, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)diphenyl ether, and 1,4-bis[4-(4-aminophenoxy)phenoxy]benzene. The content ratio of polyimide polymer (Q) to polyimide polymer (H) is preferably 10 / 90 to 90 / 10, more preferably 20 / 80 to 80 / 20, and even more preferably 30 / 70 to 70 / 30, in terms of the mass ratio of [polyimide polymer (Q)] / [polyimide polymer (H)].

[0041] Component (A) contained in the liquid crystal alignment agent of the present invention may contain polymers other than polymer (A). Specific examples of other polymers include polymers selected from the group consisting of polysiloxane, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene derivative, poly(styrene-maleic anhydride) copolymer, poly(isobutylene-maleic anhydride) copolymer, poly(vinyl ether-maleic anhydride) copolymer, poly(styrene-phenylmaleimide) derivative, and poly(meth)acrylate. 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). Other polymers may be used individually or in combination of two or more. The content of the other polymers is more preferably 0.1 to 90 parts by mass, and even more preferably 1 to 90 parts by mass, per 100 parts by mass of component (A) contained in the liquid crystal alignment agent.

[0042] <Method for producing polyimide precursors> Polyamic acid, one of the polyimide precursors, can be produced by the following method. Specifically, it can be synthesized by reacting (polycondensation reaction) a tetracarboxylic acid derivative component containing a tetracarboxylic dianhydride with the above-mentioned diamine component in the presence of an organic solvent, preferably at -20 to 150°C, more preferably at 0 to 50°C, preferably for 30 minutes to 24 hours, more preferably for 1 to 12 hours. Specific examples of organic solvents used in the above reaction include 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 polymer has high solvent solubility, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or 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. Two or more of these may be used in combination.

[0043] The reaction 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. In the reaction, the ratio of the total number of moles of diamine components to the total number of moles of tetracarboxylic acid derivative components is preferably 0.8 to 1.2. As with ordinary polycondensation reactions, the closer this molar ratio is to 1.0, the larger the molecular weight of the resulting polyamic acid.

[0044] The polyamic acid obtained from the above reaction can be recovered by precipitation by injecting the reaction solution into a poor solvent while stirring well. Alternatively, after repeating the precipitation process several times and washing with a poor solvent, purified polyamic acid powder can be obtained by drying at room temperature or by heating. The poor solvent is not particularly limited, but examples include water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.

[0045] Polyamic acid esters, which are one of the polyimide precursors, can be produced by known methods such as (1) esterifying the above polyamic acid, (2) reacting a tetracarboxylic acid derivative component containing a tetracarboxylic acid diester dichloride with a diamine component, or (3) polycondensing a tetracarboxylic acid derivative component containing a tetracarboxylic acid diester with a diamine.

[0046] The above-mentioned polyamic acid and polyamic acid ester may be end-modified polymers obtained by using a suitable end-capturing agent together with the above-mentioned tetracarboxylic acid derivative component and diamine component during their production. Examples of end-capturing agents include acid monoanhydrides such as acetic anhydride, maleic anhydride, nadic anhydride, phthalic anhydride, itaconic anhydride, 1,2-cyclohexanedicarboxylic acid anhydride, 1,3-cyclohexanedicarboxylic acid anhydride, 3-hydroxyphthalic acid anhydride, trimellitic acid anhydride, 3-(3-trimethoxysilyl)propyl)-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, and 4-ethynylphthalic acid 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; aniline and 2-aminophenol Examples include monoamine compounds such as 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; monoisocyanate compounds such as isocyanates having unsaturated bonds, such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate, 2-acryloyloxyethyl isocyanate, and 2-methacryloyloxyethyl isocyanate; and isothiocyanate compounds such as ethyl isothiocyanate and allyl isothiocyanate. The proportion of end-capturing agent used is preferably 40 moles or less, and more preferably 30 moles or less, per 100 moles of the total diamine components used. Furthermore, the proportion of end-capturing agent used is preferably 0.01 moles or more, and more preferably 0.1 moles or more, per 100 moles of the total diamine components used.

[0047] <Method for producing polyimide> The polyimide used in the present invention can be produced by imidizing the above-mentioned polyimide precursor using a known method. In polyimides, the ring-closing rate (also called the imidization rate) of the functional groups of polyamic acid or polyamic acid ester does not necessarily have to be 100%, and can be arbitrarily adjusted depending on the application and purpose. From the viewpoint of reducing the occurrence rate of labeling defects, the imidization rate of the polyimide in polymer (A) of the present invention is preferably 20 to 100%, more preferably 50 to 99%, and even more preferably 60 to 99%.

[0048] Methods for obtaining polyimide by imidizing the above-mentioned polyamic acid or polyamic acid ester include thermal imidization, in which the solution of the polyamic acid or polyamic acid ester is heated directly, and catalytic imidization, in which a catalyst (e.g., a basic catalyst such as pyridine, or an acid anhydride such as acetic anhydride) is added to the solution of the polyamic acid or polyamic acid ester.

[0049] <Solution viscosity and molecular weight of polymers> The polyamic acids, polyamic acid esters, and polyimides used in the present invention are preferably, from the viewpoint of workability, those having a solution viscosity of, for example, 10 to 1000 mPa·s when prepared as a solution with a concentration of 10 to 15% by mass, but are not particularly limited. The solution viscosity (mPa·s) of the above polymers is the value measured at 25°C using an E-type rotational viscometer for a polymer solution with a concentration of 10 to 15% by mass prepared using a good solvent for the polymer (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0050] The weight-average molecular weight (Mw) of the above-mentioned polyamic acid, polyamic acid ester, and polyimide, measured by gel permeation chromatography (GPC), is preferably 1,000 to 500,000, and more preferably 2,000 to 500,000. 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. Being within this molecular weight range ensures good liquid crystal alignment of the liquid crystal display element.

[0051] <<<Compound (B)>>> The liquid crystal alignment agent of the present invention comprises compound (B) represented by the above formula (1). Compound (B) may be used as one type or as two or more types. In addition, compound (B) itself is also a subject of the present invention, independently of the liquid crystal alignment agent of the present invention.

[0052] Examples of the divalent organic group having 1 to 10 carbon atoms in L1 of formula (1) above include a divalent hydrocarbon group having 1 to 10 carbon atoms, a divalent heteroatom-containing group that includes a group having a heteroatom between the carbon atoms of the hydrocarbon group, and a divalent organic group in which some or all of the hydrogen atoms of the above-mentioned divalent hydrocarbon group and divalent heteroatom-containing group are replaced with substituents. Examples of substituents include halogen atoms; alkoxy groups such as methoxy, ethoxy, and propoxy groups; alkoxycarbonyl groups such as methoxycarbonyl and ethoxycarbonyl groups; alkoxycarbonyloxy groups such as methoxycarbonyloxy and ethoxycarbonyloxy groups; cyano groups, nitro groups, and hydroxyl groups. Among these, halogen atoms are preferred in that they allow for the optimal acquisition of the effects of the present invention. Examples of heteroatom-containing groups include groups having at least one atom selected from the group consisting of oxygen, nitrogen, silicon, phosphorus, and sulfur atoms, and include -O-, -NR- (where R represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms), -CO-, -S-, and combinations thereof. Among these, -O- is preferred. Specific examples of divalent hydrocarbon groups include, for example, alkanes such as methane, ethane, propane, and butane; alkenes such as ethylene, propene, butene, and pentene; chain hydrocarbons having 1 to 10 carbon atoms such as ethyne, propyne, butyne, and pentine; alicyclic hydrocarbons having 3 to 10 carbon atoms such as cycloalkanes such as cyclopropane, cyclobutane, cyclopentane, and cyclohexane; cycloalkenes such as cyclopropene, cyclobutene, cyclopentene, and cyclohexene; and aromatic hydrocarbons having 6 to 10 carbon atoms such as benzene, toluene, xylene, mesitylene, naphthalene, methylnaphthalene, and dimethylnaphthalene, as well as divalent hydrocarbon groups obtained by removing two hydrogen atoms from hydrocarbons.

[0053] In formula (1) above, L1 is preferably a divalent hydrocarbon group having 1 to 10 carbon atoms, more preferably a divalent chain hydrocarbon having 1 to 10 carbon atoms, or a divalent hydrocarbon group obtained by removing two hydrogen atoms from an aromatic hydrocarbon having 6 to 10 carbon atoms. Divalent chain hydrocarbons having 1 to 10 carbon atoms are preferred, and more preferably, divalent chain hydrocarbons having 2 to 10 carbon atoms are preferred, and more preferably, divalent chain hydrocarbons having 2 to 8 carbon atoms.

[0054] In formula (1) above, E is a divalent organic group obtained by removing the hydrogen atoms contained in the two hydroxyl groups from an organic diol, and the organic diol contains a divalent organic group represented by formula (EG). The organic diol containing the divalent organic group represented by formula (EG) is not particularly limited as long as it contains formula (EG) in its molecule, but examples include: a diol in which hydrogen atoms are bonded to both ends of formula (EG); a polyester diol obtained by reacting a diol in which hydrogen atoms are bonded to both ends of formula (EG) with a polybasic acid; a polycarbonate diol having a skeleton derived from a diol in which hydrogen atoms are bonded to both ends of formula (EG) and a carbonate skeleton; and a polylactone diol obtained by ring-opening addition reaction of a diol in which hydrogen atoms are bonded to both ends of formula (EG) with lactones such as γ-butyrolactone, ε-caprolactone, and δ-valerolactone. From the viewpoint of suitably obtaining the effects of the present invention, a more preferred example is a diol in which hydrogen atoms are bonded to both ends of formula (EG). In a diol in which hydrogen atoms are bonded to both ends of the above formula (EG), the upper limit of n is preferably set so that the upper limit of the weight-average molecular weight of the diol is 5,000, more preferably so that the upper limit of the weight-average molecular weight of the diol is 4,000, and even more preferably so that the upper limit of the weight-average molecular weight of the diol is 3,000. From the viewpoint of improving liquid crystal orientation, the upper limit of n is preferably 40, more preferably 30, and particularly preferably 20.

[0055] Specific examples of diols containing a divalent organic group represented by the above formula (EG) include tetraethylene glycol, pentaethylene glycol, hexaethylene glycol, and the following products manufactured by Sanyo Chemical Industries: PEG-300, PEG-400, PEG-600, PEG-1000, PEG-1500, PEG-2000, PEG-4000N, PEG-4000S, PEG-6000E, PEG-6000P, PEG-10000, PEG-13000, PEG-20000; and the following products manufactured by Merck: PEG300, PEG1000, PEG2000, PEG4000, PEG6000, PEG8000, PEG10000, PEG1 2000, PEG20000, PEG35000; SIGMA-ALDRICH product numbers P2139, P3265, P3515, 81210, 81240, 81260, 81285, 81310, 181986, 181994, 182001, 182028, 189456, 202304, 202312 ,202320,202339,202398,202421,202436,202444,202452,295906,309028,372773,372781,373001,412325,435406,435422,435457,637726;Product name SINOPOL manufactured by Chunichi Synthetic Chemical Co., Ltd. Examples include PEG600, SINOPOL PEG1000, SINOPOL PEG1500, SINOPOL PEG4000; products sold under the brand names PEG#300, PEG#400, PEG#600, PEG#1000, PEG#1500, PEG#1540, PEG#4000, and PEG#6000M by Lion Specialty Chemicals; and products sold under the brand names Polyethylene Glycol 400 and Polyethylene Glycol 600 by Tokyo Chemical Industry Co., Ltd.Preferred specific examples of diols in which hydrogen atoms are bonded to both ends of the above formula (EG) include pentaethylene glycol, hexaethylene glycol, Sanyo Chemical Industries' trade names PEG-300, PEG-400, PEG-600, PEG-1000, Merck's trade names PEG300, PEG1000, Chunichi Synthetic Chemicals' trade names SINOPOL PEG600, SINOPOL PEG1000, Lion Specialty Chemicals' trade names PEG#300, PEG#400, PEG#600, PEG#1000, and Tokyo Chemical Industries' trade names Polyethylene Glycol 400, Polyethylene Glycol Examples include polyethylene glycol represented by 600, or tetrapropylene glycol, pentapropylene glycol, hexapropylene glycol, polypropylene glycol (more preferably polypropylene glycol with an average molecular weight of 400 to 5,000), copolymers consisting of ethylene oxide and propylene oxide with an average molecular weight of 500 to 5,000, etc. The polyethylene glycol and polypropylene glycol mentioned above may be obtained by an anionic ring-opening polymerization reaction of ethylene oxide or propylene oxide. This anionic ring-opening polymerization reaction can be carried out using water, ethylene glycol, or propylene glycol and a catalytic amount of base (e.g., potassium hydroxide). In addition, the average molecular weight of the glycol exemplified in the diol containing a divalent organic group represented by (EG) above is the weight-average molecular weight obtained using polystyrene as the reference by gel permeation chromatography (GPC).

[0056] As for compound (B), which is the compound represented by formula (1) above, a compound represented by any of the following formulas (b-1) to (b-4) is more preferable. [ka]

[0057] The content of compound (B) 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, per 100 parts by mass of component (A).

[0058] <Liquid crystal alignment agent> The liquid crystal alignment agent of the present invention is used to produce a liquid crystal alignment film, and from the viewpoint of forming a uniform thin film, it takes the form of a coating solution. In the liquid crystal alignment agent of the present invention, it is preferable that it is a coating solution containing the polymer component described above and a solvent. The content (concentration) of the polymer component contained in the liquid crystal alignment agent of the present invention can be appropriately changed depending on the desired thickness of the coating film to be formed. However, from the viewpoint of forming a uniform and defect-free coating film, it is preferable to have 1% by mass or more relative to the total amount of the liquid crystal alignment agent, and from the viewpoint of the storage stability of the solution, it is preferable to have 10% by mass or less. From the viewpoint of suitably obtaining the effects of this disclosure, the content ratio of polymer (A) in the liquid crystal alignment agent is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably 50 parts by mass or more, based on 100 parts by mass of the total amount of polymers contained in the liquid crystal alignment agent. When the liquid crystal alignment agent contains other polymers, the content ratio of polymer (A) is preferably 10 to 90 parts by mass, and more preferably 20 to 80 parts by mass, based on 100 parts by mass of polymer components contained in the liquid crystal alignment agent.

[0059] The solvent contained in the liquid crystal alignment agent is not particularly limited as long as it allows the polymer components to dissolve uniformly. Specific examples include N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropanamide, and 3-butoxy-N,N-dimethylpropanamide. Examples include 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, and N-cyclohexyl-2-pyrrolidone (collectively referred to as "good solvents"). Among these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, or γ-butyrolactone are preferred. The content of good solvent 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.

[0060] Furthermore, it is preferable to use a mixed solvent in which the solvent contained in the liquid crystal alignment agent is combined with a solvent (also called a poor solvent) that improves the coatability and surface smoothness of the coating film when applying the liquid crystal alignment agent. Specific examples of poor solvents used in combination are listed below, but are not limited to these.

[0061] For example, diisopropyl ether, diisobutyl ether, diisobutylcarbinol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol Examples include 2-(2-butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, and diisobutyl ketone (2,6-dimethyl-4-heptanone). The content of the poor solvent is preferably 1 to 80% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass. The type and content of the poor solvent are appropriately selected depending on the coating apparatus, coating conditions, and coating environment of the liquid crystal alignment agent.

[0062] Among these, diisobutylcarbinol, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, or diisobutyl ketone are preferred.

[0063] Preferred solvent combinations of good and poor solvents include: N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and diisobutyl ketone, N-methyl-2-pyrrolidone and γ- Examples include butyrolactone, propylene glycol monobutyl ether and diisopropyl ether; N-methyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol monomethyl ether; N-methyl-2-pyrrolidone, 3-ethoxypropionate ethyl and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, propylene glycol monobutyl ether and diethylene glycol monoethyl ether; γ-butyrolactone, dipropylene glycol monomethyl ether and dipropylene glycol dimethyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisobutylcarbinol; N-methyl-2-pyrrolidone, γ-butyrolactone and dipropylene glycol dimethyl ether; and N-methyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol dimethyl ether.

[0064] The liquid crystal alignment agent of the present invention may additionally contain components other than polymer components and solvents (hereinafter also referred to as additive components). Examples of such additive components include compounds for increasing the strength of the liquid crystal alignment film (hereinafter also referred to as crosslinking compounds), adhesion aids for improving the adhesion between the liquid crystal alignment film and the substrate, and the adhesion between the liquid crystal alignment film and the sealant, and dielectrics and conductive materials for adjusting the dielectric constant and electrical resistance of the liquid crystal alignment film.

[0065] Examples of the above-mentioned crosslinkable compounds include 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 structures, cyclocarbonate groups, blocked isocyanate groups, hydroxyl groups, and alkoxy groups, and a crosslinkable compound (c-2) having a polymerizable unsaturated group. Preferred specific examples of the above crosslinkable compounds (c-1) and (c-2) include the following compounds: Compounds having an epoxy group 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) Compounds in which a tertiary nitrogen atom is bonded to an aliphatic carbon atom, such as methane, 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 WO2017 / 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 Publication No. WO2011 / 132751; Compounds having an oxazoline structure 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 a hydroxyl group and / or alkoxy group 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-dimethoxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)-1,1,1,3,3,3-hexafluoropropane, compounds described in WO2015 / 072554, paragraph

[0058] of Japanese Patent Publication No. 2016-118753, compounds described in Japanese Patent Publication No. 2016-200798, compounds described in WO2010 / 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 above compounds are examples of crosslinkable compounds and are not limited to these. For example, other components disclosed on pages 53

[0105] to 55

[0116] of WO2015 / 060357 may be included. Furthermore, two or more crosslinkable compounds may be combined.

[0067] When using a crosslinkable compound, the content of the crosslinkable compound in the liquid crystal alignment agent is preferably 0.5 to 20 parts by mass, and more preferably 1 to 15 parts by mass, per 100 parts by mass of the polymer component contained in the liquid crystal alignment agent.

[0068] Examples of the adhesion aids mentioned above 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, and N-ethoxycarbonyl-3-aminopropyl Trimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-3-triethoxysilylpropyltriethylenetetramine, N-3-trimethoxysilylpropyltriethylenetetramine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonylacetate, 9-triethoxysilyl-3,6-diazanonylacetate, N-benzyl-3-aminopropyltrimethoxysilane, N- Benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane Examples of silane coupling agents include silane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris[3-(trimethoxysilyl)propyl]isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatetopropyltriethoxysilane. When an adhesion aid is used, the content of the adhesion aid in the liquid crystal alignment agent 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. Examples of dielectric or conductive materials include monoamines having nitrogen-containing aromatic heterocycles, such as 3-picolylamine. When a dielectric or conductive material is used, the content of the dielectric or conductive material in the liquid crystal alignment agent 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] (Liquid crystal alignment film) The liquid crystal alignment film of the present invention is formed using the liquid crystal alignment agent of the present invention described above. The liquid crystal alignment film of the present invention can be used for horizontal alignment or vertical alignment. Among the vertical alignment type liquid crystal alignment films, liquid crystal alignment films used in vertical alignment type liquid crystal display elements such as the VA method, PSA (Polymer Sustained Alignment) method, or SC-PVA (Surface-Controlled Patterned Vertical Alignment) method are preferred. Among the horizontal alignment type liquid crystal alignment films, liquid crystal alignment films used in liquid crystal display elements such as the TN method, IPS method, or FFS method are preferred. Furthermore, the liquid crystal alignment agent of the present invention can be used for liquid crystal alignment films for phase difference films, liquid crystal alignment films for scanning antennas and liquid crystal array antennas, or liquid crystal alignment films 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.

[0070] The present invention provides a method for manufacturing a liquid crystal alignment film, which includes, for example, applying the above-mentioned liquid crystal alignment agent to a substrate, firing it, and irradiating the resulting film with polarized radiation. A preferred embodiment of the method for manufacturing a liquid crystal alignment film of the present invention includes, for example, a step of applying the above-mentioned liquid crystal alignment agent to a substrate (step (1)), a step of firing the applied liquid crystal alignment agent (step (2)), and optionally a step of performing an alignment treatment on the film obtained in step (2) (step (3)).

[0071] <Process (1)> The substrate on which the liquid crystal alignment agent used in the present invention is coated is not particularly limited as long as it is a highly transparent substrate, and can be a glass substrate, a silicon nitride substrate, an acrylic substrate, a plastic substrate such as a polycarbonate substrate, etc. In this case, it is preferable to use a substrate on which ITO (Indium Tin Oxide) electrodes for driving the liquid crystal are formed, from the viewpoint of simplifying the process. Furthermore, in the case of a reflective liquid crystal display element, an opaque material such as a silicon wafer can be used for only one side of the substrate, and in this case, a light-reflecting material such as aluminum can be used for the electrodes.

[0072] Methods for applying liquid crystal alignment agents to a substrate and forming a film include screen printing, offset printing, flexographic printing, inkjet printing, and spray printing. Among these, the inkjet method for coating and forming the film is particularly suitable.

[0073] <Process (2)> Step (2) is a step of firing the liquid crystal alignment agent coated on the substrate to form a film. After coating the liquid crystal alignment agent on the substrate, the solvent can be evaporated or the amic acid or amic acid ester in the polymer can be thermally imidized using a heating means such as a hot plate, a heat circulation oven, or an IR (infrared) oven. The drying and firing steps after coating the liquid crystal alignment agent of the present invention can be performed at any temperature and time, and may be performed multiple times. The temperature at which the solvent of the liquid crystal alignment agent is evaporated can be, for example, 40 to 180°C as the temperature of the heating means, but from the viewpoint of shortening the process, it may be performed at 40 to 150°C. The firing time is not particularly limited, but for example it is 1 to 10 minutes, preferably 1 to 5 minutes. If, in addition to the step of evaporating the solvent, a step of thermally imidizing the amic acid or amic acid ester in the polymer is performed, after the step of evaporating the solvent, a further firing step can be performed at a temperature range of, for example, 150 to 300°C, preferably 150 to 250°C as the temperature of the heating means. The firing time in the thermal imidization process is not particularly limited, but is, for example, 5 to 40 minutes, preferably 5 to 30 minutes. If the resulting film is too thin, the reliability of the liquid crystal display element may decrease. Therefore, the film thickness is preferably 5 to 300 nm, and more preferably 10 to 200 nm.

[0074] <Process (3)> Step (3) is a step of aligning the film obtained in step (2), if applicable. That is, in vertically aligned liquid crystal display elements such as the VA method or PSA method (Polymer Sustained Alignment), the formed coating can be used as is as a liquid crystal alignment film, but the coating may be subjected to an alignment-imparting treatment. As a method for aligning the liquid crystal alignment film, a rubbing method may be used, but a photo-alignment method is preferred. As a photo-alignment method, the surface of the film-like material is irradiated with radiation polarized in a certain direction, and if applicable, a heat treatment is performed to impart liquid crystal alignment properties (also called liquid crystal alignment ability). As radiation, ultraviolet light or visible light having a wavelength of 100 to 800 nm can be used. In particular, ultraviolet light having a wavelength of 100 to 400 nm, and more preferably 200 to 400 nm, is preferred.

[0075] The radiation doses mentioned above range from 1 to 10,000 mJ / cm². 2 Preferably, 100 to 5,000 mJ / cm² 2 This is more preferable. Furthermore, when irradiating with radiation, the substrate having the above-mentioned film may be irradiated while being heated at 50 to 250°C in order to improve the liquid crystal alignment. The liquid crystal alignment film produced in this manner can stably align liquid crystal molecules in a certain direction. Furthermore, using the method described above, the liquid crystal alignment film irradiated with polarized radiation can be brought into contact with these materials using a solvent, or the irradiated liquid crystal alignment film can be heat-treated.

[0076] The solvent used in the above contact treatment is not particularly limited, as long as it is a solvent that dissolves the decomposition products generated from the film-like material by irradiation with radiation. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, and cyclohexyl acetate. Among these, water, 2-propanol, 1-methoxy-2-propanol, or ethyl lactate are preferred in terms of versatility and solvent safety. More preferably, water, 1-methoxy-2-propanol, or ethyl lactate are preferred. The solvent may be used individually or in combination of two or more types.

[0077] Examples of the above-mentioned contact treatments include immersion treatment and spray treatment. The treatment time in these treatments is preferably 10 seconds to 1 hour, in order to efficiently dissolve the decomposition products generated from the film-like material by irradiation with radiation. In particular, immersion treatment for 1 to 30 minutes is more preferable. The solvent used in the above-mentioned contact treatment may be at room temperature or heated, but is preferably 10 to 80°C, and more preferably 20 to 50°C. In addition, ultrasonic treatment or the like may be performed as needed in terms of the solubility of the decomposition products.

[0078] After the above contact treatment, it is preferable to rinse (also called rinsing) or calcination with a low-boiling point solvent such as water, methanol, ethanol, 2-propanol, acetone, or methyl ethyl ketone. In this case, either rinsing or calcination may be performed, or both may be performed. The calcination temperature is preferably 150 to 300°C, more preferably 180 to 250°C, and even more preferably 200 to 230°C. The calcination time is preferably 10 seconds to 30 minutes, and more preferably 1 to 10 minutes. The heat treatment of the irradiated coating film is preferably performed at 50 to 300°C for 1 to 30 minutes, and more preferably at 120 to 250°C for 1 to 30 minutes.

[0079] (Liquid crystal display element) The liquid crystal display element of the present invention has the liquid crystal alignment film of the present invention. The liquid crystal alignment film of the present invention is suitable as a liquid crystal alignment film for transverse electric field type liquid crystal display elements such as IPS type and FFS type, from the viewpoint of obtaining high liquid crystal alignment properties, and is particularly useful as a liquid crystal alignment film for FFS type liquid crystal display elements. A liquid crystal display element can be manufactured by first obtaining a substrate with a liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention, then fabricating a liquid crystal cell by a known method, and finally arranging liquid crystal within the liquid crystal cell. Specifically, the following two methods can be mentioned.

[0080] The first method involves first arranging two substrates opposite each other with a gap (cell gap) in between so that their respective liquid crystal alignment films face each other. Next, the periphery of the two substrates is bonded together using a sealant, and the liquid crystal composition is injected and filled into the cell gaps partitioned by the substrate surface and the sealant, making contact with the film surface, and then the injection holes are sealed.

[0081] 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. After that, the other substrate is bonded together so that the liquid crystal alignment films face each other, and the liquid crystal composition is spread over 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.

[0082] In either the first or second 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. When a rubbing treatment is performed on the coating film, the two substrates are positioned opposite each other so that the rubbing directions in each coating film are at a predetermined angle to each other, for example, orthogonal or antiparallel. Similarly, when a photo-alignment treatment is performed, the substrates are positioned opposite each other so that their orientation directions are at a predetermined angle to each other, for example, orthogonal or antiparallel. As a sealant, for example, an epoxy resin containing aluminum oxide spheres as a curing agent and spacer can be used. Examples of liquid crystals include nematic liquid crystals and smectic liquid crystals, with nematic liquid crystals being preferred.

[0083] The liquid crystal composition is not particularly limited and is a composition containing at least one liquid crystal compound (liquid crystal molecule). Either a liquid crystal composition with positive dielectric anisotropy (also called a positive-type liquid crystal composition or positive-type liquid crystal) or a liquid crystal composition with negative dielectric anisotropy (also called a negative-type liquid crystal composition or negative-type liquid crystal) may be used, but a negative-type liquid crystal composition is preferred. 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 (methacryloyl groups, etc.); optically active compounds (e.g., S-811 from 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. Next, the polarizing plates are installed. Specifically, a pair of polarizing plates are attached to the side of the two substrates opposite to the liquid crystal layer. Examples of polarizing plates include polarizing plates 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 polarizing plates made of the H film itself. [Examples]

[0084] The present invention will be further described in detail below with reference to examples, but the present invention is not limited to these examples. The abbreviations of the compounds used and the methods for measuring each of their physical properties are as follows.

[0085] (organic solvent) NMP:N-methyl-2-pyrrolidone GBL: γ-Butyrolactone BCS: Butyl cellosolve DMSO: Dimethyl sulfoxide

[0086] (Diamine) DA-1 to DA-13: Compounds represented by the following formulas (DA-1) to (DA-13), respectively. [ka] [ka]

[0087] (Tetracarboxylic acid dianhydride) CA-1 to CA-5: Compounds represented by the following formulas (CA-1) to (CA-5), respectively. [ka]

[0088] (Compound (B)) [ka]

[0089] (Other additives) [ka]

[0090] (Reaction reagent) TBACl: Tetrabutylammonium chloride DMAP: 4-dimethylaminopyridine Boc2O: Ditert-butyl dicarbonate

[0091] <Viscosity> In the synthesis example, the viscosity of the polymer solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample volume of 1.1 mL, a cone rotor TE-1 (1°34', R24), and a temperature of 25°C.

[0092] <Measurement of the imidization rate of polyimides> The imidization rate of polyimides in the synthesis example was measured as follows. 30 mg of polyimide powder was placed in an NMR (nuclear magnetic resonance) sample tube (NMR sampling tube standard, φ5 (manufactured by Kusano Science Co., Ltd.)), 0.53 mL of deuterated dimethyl sulfoxide (DMSO-d6, 0.05 mass% TMS (tetramethylsilane) mixture) was added, and the solution was completely dissolved by sonication. The 500 MHz proton NMR of this solution was measured using an NMR analyzer (JNW-ECA500) (manufactured by JEOL Datum Corporation). The imidization rate was determined by using the following formula, with a reference proton derived from a structure that does not change before and after imidization, 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 appearing around 9.5 ppm to 10.0 ppm. Imidization rate (%) = (1 - α·x / y) × 100 In the above formula, x is the integrated value of proton peaks derived from the NH group of the amic acid, y is the integrated value of the reference proton peaks, and α is the ratio of the number of reference protons to one NH group proton of the amic acid in the case of polyamic acid (imidization rate of 0%).

[0093] [Synthesis of compound (B)] Compound (B), AD-1, is a novel compound not yet published in the literature, and its synthesis method is described in detail below.

[0094] The product described in Synthesis Example 1 below is 1 Identified by 1H-NMR analysis (analytical conditions are as follows). Equipment: BRUKER ADVANCE III-500MHz Measurement solvent: Deuterated dimethyl sulfoxide (DMSO-d6) Reference substance: Tetramethylsilane (TMS) (δ 0.0 ppm for 1 H)

[0095] (Synthesis Example 1: Synthesis of AD-1) [ka]

[0096] To tetraethylene glycol (10.0 g, 51.5 mmol), succinic anhydride (12.9 g, 129 mmol), dichloromethane (60 g), and DMAP (3.14 g, 25.7 mmol) were added and the mixture was heated under reflux at 50°C for 6 hours to allow the reaction to proceed. After the reaction was complete, the mixture was cooled to room temperature (25°C) and washed twice with 2 N hydrochloric acid (60 g). The organic phase was concentrated and vacuum-dried at 40°C to obtain AD-1-1 (yield: 15.6 g, 39.6 mmol, yield: 77%). The results are as follows: 1 The results of the 1H-NMR spectrum confirmed that it was AD-1-1. 1H-NMR(500MHz)in DMSO-d6:δ(ppm)=12.20(br,2H),4.12(t,4H),3.59(t,4H),3.53(s,8H),2.51(t,4H),2.47(t,4H).

[0097] AD-1-1 (5.00 g, 12.7 mmol), TBACl (1.06 g, 3.80 mmol), and DMSO (15 g) were added to a flask and stirred at room temperature (25°C). Epichlorohydrin (7.04 g, 76.1 mmol) was added dropwise, and the mixture was heated and stirred at 80°C for 22 hours. Stirring was stopped, ethyl acetate (50 g) and water (15 g) were added, and then heptane (10 g) was added to dilute the mixture. The separated organic phase was washed twice with water (30 g) (hereinafter referred to as organic phase 1). Ethyl acetate (40 g) and heptane (10 g) were added to the separated aqueous phase, and the organic phase was extracted by liquid-liquid extraction (hereinafter referred to as organic phase 2). The mixture of organic phase 1 and organic phase 2 described above was concentrated to obtain an AD-1-2 mixture (yield: 7.02 g, also containing some AD-1). The obtained AD-1-2 mixture was used directly in the next step.

[0098] In a flask, the AD-1-2 mixture (7.02 g), acetonitrile (42 g), and potassium carbonate (5.26 g, 38.1 mmol) were added and heated and stirred at 80°C for 20 hours. After stopping the stirring, the reaction mixture was filtered, and the filtrate was concentrated to obtain crude AD-1 (5.44 g). The crude AD-1 was purified by silica gel column chromatography (eluent: heptane / ethyl acetate = 1 / 1 → 1 / 4 (volume ratio)) to obtain AD-1 (yield: 2.34 g, 4.61 mmol, two-step yield from AD-1-1: 36%). The results are shown below. 1 The results of the 1H-NMR spectrum confirmed that it was AD-1. 1H-NMR(500MHz)in DMSO-d6:δ(ppm)=4.38(d,J=2.5Hz,1H),4.35(d,J=2.5Hz,1H),4.14-4.12(m,4H),3.85-3 .82(m,2H),3.60(t,4H),3.53(s,8H),3.19-3.17(m,2H),2.78(t,2H),2.63-2.58(m,10H).

[0099] [Synthesis of polymers] (Synthesis Example 2) In a 200 mL round-bottom flask equipped with a stirrer and nitrogen inlet tube, DA-1 (8.04 g, 40.2 mmol), DA-2 (4.36 g, 10.9 mmol), and DA-3 (12.2 g, 21.9 mmol) were weighed out, NMP (98.4 g) was added, and the mixture was stirred while supplying nitrogen to dissolve the compounds. While stirring this diamine solution under water cooling, CA-1 (9.40 g, 47.4 mmol) was added, followed by the addition of NMP (37.6 g), and the mixture was stirred at 50°C under a nitrogen atmosphere for 2 hours. Furthermore, CA-2 (4.65 g, 23.7 mmol) and NMP (18.6 g) were added, and the mixture was stirred at 23°C under a nitrogen atmosphere for 2 hours to obtain a polyamic acid solution (PAA-I, viscosity: 1250 mPa·s). The above polyamic acid solution (PAA-I) (100g) was weighed into a 200mL Erlenmeyer flask containing a stirring bar, and Boc2O (1.24g, 5.68 mmol), which is an end-capturing agent, was added. The mixture was stirred at 40°C for 15 hours to obtain end-modified polyamic acid solution (PAA-I-1). PAA-I-1 (100g) was placed in a 200mL Erlenmeyer flask containing a stirring bar, and NMP (66.7g), acetic anhydride (14.2g), and pyridine (4.70g) were added. The mixture was stirred at room temperature for 30 minutes, and then reacted at 60°C for 4 hours. The reaction solution was poured into methanol (650g), and the resulting precipitate was filtered off. After washing the precipitate with methanol, it was dried under reduced pressure at 80°C to obtain polyimide powder (imidization rate: 89%). Furthermore, 9.60 g of this polyimide powder was taken into a 100 mL Erlenmeyer flask containing a stirring bar, 70.4 g of NMP was added, and the mixture was stirred at 70°C for 24 hours to dissolve it and obtain a solution of polyimide (SPI-1).

[0100] (Synthesis Example 3) In a 50 mL round-bottom flask equipped with a stirrer and nitrogen inlet tube, DA-4 (2.70 g, 18.0 mmol) was weighed out, NMP (15.3 g) was added, and the mixture was stirred while supplying nitrogen to dissolve it. While stirring this diamine solution under water cooling, CA-3 (2.25 g, 9.00 mmol) was added, followed by NMP (12.8 g), and the mixture was stirred at 50°C under a nitrogen atmosphere for 6 hours. Furthermore, CA-4 (2.52 g, 8.55 mmol) and NMP (14.3 g) were added, and the mixture was stirred at 50°C under a nitrogen atmosphere for 3 hours to obtain a polyamic acid (PAA-1) solution (viscosity: 330 mPa·s).

[0101] (Synthesis Example 4) In a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, DA-9 (0.865 g, 8.00 mmol), DA-10 (3.84 g, 12.0 mmol), DA-11 (2.93 g, 12.0 mmol), DA-12 (2.73 g, 8.00 mmol), and NMP (119 g) were added, and the mixture was stirred at room temperature for 1 hour while supplying nitrogen. Subsequently, CA-5 (8.65 g, 38.6 mmol) and NMP (17.9 g) were added, and the mixture was stirred at 40°C for 18 hours to obtain a polyamic acid solution (viscosity: 405 mPa·s). 100 g of the obtained polyamic acid solution was weighed into a 200 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. NMP was added to achieve a solid content concentration of 9% by mass, followed by 7.60 g of acetic anhydride and 1.57 g of pyridine. The mixture was stirred at room temperature for 30 minutes, and then reacted at 55°C for 3 hours. The reaction solution was added to 428 g of methanol, and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 60°C to obtain polyimide powder. The imidization rate of this polyimide powder was 66%. To the obtained polyimide powder, NMP was added to achieve a solid content concentration of 12% by mass, and the mixture was stirred at 80°C for 18 hours to dissolve it, thereby obtaining a polyimide (SPI-2) solution.

[0102] (Synthesis Example 5) In a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, DA-6 (1.59 g, 7.98 mmol), DA-8 (0.790 g, 2.65 mmol), DA-13 (1.12 g, 2.66 mmol), and NMP (47.8 g) were added, and the mixture was stirred at room temperature for 1 hour while supplying nitrogen. Subsequently, CA-4 (3.73 g, 12.7 mmol) and NMP (5.30 g) were added, and the mixture was stirred at 70°C for 12 hours to obtain a solution of polyamic acid (PAA-2) with a solid content of 12% by mass (viscosity: 390 mPa·s).

[0103] [Preparation of liquid crystal alignment agent] (Example 1) In a 50 mL Erlenmeyer flask containing a stirring bar, weigh out 2.00 g of the polyimide (SPI-1) solution obtained in Synthesis Example 2 and 3.73 g of the polyamic acid (PAA-1) solution obtained in Synthesis Example 3. Add 0.83 g of NMP, 8.40 g of GBL, and 4.00 g of BCS, then add 0.24 g of a 10% by mass NMP solution of AD-1, and stir at room temperature for 2 hours to obtain liquid crystal alignment agent (1).

[0104] (Example 2, Comparative Examples 1-4) Liquid crystal alignment agents (2) to (6) were obtained by performing the same procedure as in Example 1, except that the type and amount of polymer solution and solvent used were changed as shown in Table 1 below. Additives AD-1 to AD-3 in Table 1 were added as NMP solutions containing 10% by mass each.

[0105] [Table 1]

[0106] [Fabrication of liquid crystal display elements (rubbing alignment treatment)] A liquid crystal cell is fabricated that incorporates a configuration of a liquid crystal display element in fringe field switching (FFS) mode. First, a substrate with electrodes was prepared. The substrate was a glass substrate measuring 35 mm x 40 mm and with a thickness of 0.7 mm. On the substrate, an ITO electrode (thickness: 50 nm, electrode width: 20 mm vertically, 10 mm horizontally) with a solid pattern was formed as the first layer, constituting the counter electrode. On top of the first layer counter electrode, a SiN (silicon nitride) film deposited by CVD (chemical vapor deposition) was formed as the second layer. The thickness of the second SiN film was 500 nm, and it was a thickness that functioned as an interlayer insulating film. On top of the second SiN film, a comb-shaped pixel electrode (thickness: 50 nm) formed by patterning the ITO film was placed as the third layer, forming two pixels, the first and second pixels. The size of each pixel was 10 mm vertically and approximately 5 mm horizontally. At this time, the first layer counter electrode and the third layer pixel electrode were electrically insulated by the action of the second layer SiN film.

[0107] The third layer of pixel electrodes had a comb-like shape, with multiple electrode elements, each 3 μm wide and bent at an internal angle of 160° in the center, arranged parallel to each other at intervals of 6 μm. Each pixel had a first region and a second region, separated by lines connecting the bent portions of the multiple electrode elements.

[0108] Comparing the first and second regions of each pixel, it was found that the formation directions of the electrode elements of the pixel electrodes constituting them were different. Specifically, using the direction connecting the bent portions of the multiple electrode elements as a reference, in the first region of the pixel, the electrode elements of the pixel electrodes were formed at an 80° clockwise angle, while in the second region of the pixel, the electrode elements of the pixel electrodes were formed at an 80° counterclockwise angle. In other words, the first and second regions of each pixel were configured such that the direction of the rotational movement (in-plane switching) of the liquid crystal induced by the voltage applied between the pixel electrode and the counter electrode was opposite to that of the first and second regions of the pixel.

[0109] Next, using the liquid crystal alignment agents (1) to (3) obtained in Example 1 and Comparative Examples 1 to 2, the liquid crystal alignment agent filtered through a 1.0 μm pore size filter was applied by spin coating to the electrode-equipped substrate and a glass substrate having a columnar spacer with a height of 4 μm and an ITO film deposited on its back surface, and dried on a hot plate at 80°C for 2 minutes. After that, it was baked in a hot air circulating oven at 230°C for 30 minutes to obtain a substrate with a liquid crystal alignment film thickness of 60 nm. The surface of this liquid crystal alignment film-equipped substrate was subjected to rubbing alignment treatment with a rayon cloth (YA-20R manufactured by Yoshikawa Chemical Co., Ltd.) (roller diameter: 120 mm, roller rotation speed: 1000 rpm, moving speed: 20 mm / sec, pressing length: 0.4 mm, rubbing direction: 180° to the direction connecting the bent portions of the multiple electrode elements of the third layer's pixel electrode). Subsequently, the substrates were cleaned by ultrasonic irradiation in pure water for 1 minute, water droplets were removed with an air blower, and then dried at 80°C for 15 minutes to obtain substrates with liquid crystal alignment films. Two of the obtained substrates with liquid crystal alignment films were made into a pair, and a sealant (Mitsui Chemicals XN-1500T) was printed on the substrates, leaving a liquid crystal injection port. The other substrate was then bonded to the pair with the liquid crystal alignment film surfaces facing each other and the rubbing directions being opposite parallel. After that, a heat treatment was performed at 120°C for 90 minutes to cure the sealant and create an empty cell with a cell gap of 4 μm. Negative liquid crystal MLC-7026 (Merck) was injected into this empty cell by a reduced-pressure injection method, and the injection port was sealed to obtain an FFS type liquid crystal display element. After that, the obtained liquid crystal display element was heated at 120°C for 1 hour, left overnight at 23°C, and then used for evaluation.

[0110] [Fabrication of liquid crystal display elements (photo-alignment treatment)] A glass substrate with electrodes and a spacer similar to those used in rubbing-oriented liquid crystal cells was employed. The liquid crystal alignment agents (4) to (6) obtained in Example 2 and Comparative Examples 3-4 were filtered through a pore size filter of 1.0 μm, and then applied to the prepared electrode substrate and glass substrate by spin coating. After drying on a hot plate at 80°C for 2 minutes, the coatings were baked in an IR oven at 230°C for 30 minutes to form a 100 nm thick coating. Polarized ultraviolet light at 300 mJ / cm² was then applied to the surface of this coating. 2The substrates were irradiated and oriented in such a manner. The substrates were then baked again in an IR oven at 230°C for 30 minutes to obtain a substrate with a liquid crystal alignment film. The two substrates were made into a pair, and a sealant (Mitsui Chemicals XN-1500T) was printed around the edges, leaving a liquid crystal injection port. The other substrate was then bonded to the substrate so that the orientation direction of the liquid crystal alignment film surfaces was 0°. After that, a heat treatment was performed at 120°C for 90 minutes to cure the sealant and create an empty cell. Negative liquid crystal MLC-7026 (Merck) was injected into this empty cell by a reduced-pressure injection method, and the injection port was sealed to obtain an FFS-driven liquid crystal cell.

[0111] [Evaluation of afterimage characteristics using long-term AC power] The FFS-driven liquid crystal cell prepared as described above was subjected to an AC voltage of ±5.8V at a frequency of 60Hz for 120 hours in a constant temperature environment of 60°C. After that, the pixel electrode and counter electrode of the liquid crystal cell were short-circuited and left at room temperature for one day. For the liquid crystal cell that underwent the above processing, the deviation between the orientation direction of the liquid crystal in the first region of the pixel and the orientation direction of the liquid crystal in the second region was calculated as the angle Δθ in the state where no voltage was applied. Specifically, a liquid crystal cell was placed between two polarizing plates arranged so that their polarization axes were orthogonal. The backlight was then turned on, and the arrangement angle of the liquid crystal cell was adjusted so that the transmitted light intensity of the first region of the pixel was minimized. Next, the rotation angle (Δθ) required to rotate the liquid crystal cell so that the transmitted light intensity of the second region of the pixel was minimized was determined. The afterimage characteristics under long-term AC drive are considered better the smaller this rotation angle value is. Specifically, a rotation angle of 0.20 degrees or less was evaluated as "○" and a rotation angle exceeding 0.20 degrees was evaluated as "×".

[0112] [Membrane strength evaluation] A liquid crystal alignment agent filtered through a 1.0 μm pore size filter was applied to the ITO surface of a glass substrate with ITO electrodes covering the entire surface by spin coating, and dried on an 80°C hot plate for 2 minutes. Then, it was baked in a 230°C hot air circulating oven for 30 minutes to obtain a substrate with a 60 nm thick liquid crystal alignment film. This liquid crystal alignment film was subjected to rubbing alignment treatment with a rayon cloth (roller diameter: 120 mm, roller rotation speed: 1000 rpm, movement speed: 20 mm / sec, pressing length: 0.5 mm, number of rubbings: 2). The haze value of this substrate was measured using a haze meter (Suga Test Instruments Co., Ltd., product name: HZ-V3). A smaller haze value indicates less film abrasion, i.e., higher film strength. A haze value of 0.15 or less was evaluated as "○", a value between 0.15 and 0.25 as "△", and a value above 0.25 as "×".

[0113] Table 1 below shows the evaluation results for afterimage evaluation of FFS-driven liquid crystal cells and the evaluation results for film hardness testing of liquid crystal alignment films in Examples 1-2 and Comparative Examples 1-4.

[0114] [Table 2]

[0115] As shown in Table 2, when AD-1 was applied as a liquid crystal alignment agent, a liquid crystal alignment film with good liquid crystal alignment properties and high film hardness was obtained. [Industrial applicability]

[0116] The liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention can be suitably used in various liquid crystal display elements, such as IPS-driven and FFS-driven liquid crystal display elements. Furthermore, these display elements are not limited to liquid crystal displays intended for display purposes, but are also useful in dimmable windows and light shutters that control the transmission and blocking of light.

[0117] Furthermore, the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2021-175589, filed on October 27, 2021, are incorporated herein by reference as disclosure of the present invention.

Claims

1. A liquid crystal alignment agent containing the following component (A) and compound (B) represented by the following formula (1). (A) A polymer component containing a polymer (A) selected from the group consisting of a polyimide precursor, which is obtained by polymerizing a tetracarboxylic acid derivative component containing at least one compound selected from the group consisting of tetracarboxylic dianhydrides and derivatives thereof, with a diamine component, and a polyimide which is an imidized product of the polyimide precursor. 【Chemistry 1】 (In formula (1), L １ It is a divalent organic group having 1 to 10 carbon atoms, and multiple L １ These may be the same or different. E is a divalent organic group obtained by removing the hydrogen atoms contained in the two hydroxyl groups from an organic diol, and includes a divalent organic group represented by the following formula (EG). 【Chemistry 2】 (In formula (EG), n is an integer greater than or equal to 4. R represents a hydrogen atom or a methyl group. * represents a bond position.)

2. Said L １ The liquid crystal alignment agent according to claim 1, wherein the group is a divalent hydrocarbon group having 1 to 10 carbon atoms.

3. The liquid crystal alignment agent according to claim 1 or 2, wherein E is a divalent organic group obtained by removing the hydrogen atoms contained in the two hydroxyl groups from a diol in which hydrogen atoms are bonded to both ends of formula (EG).

4. The liquid crystal alignment agent according to any one of claims 1 to 3, wherein E is a divalent organic group obtained by removing hydrogen atoms contained in two hydroxyl groups from an organic diol having an upper limit of 5,000 weight-average molecular weight.

5. The liquid crystal alignment agent according to any one of claims 1 to 4, wherein the compound (B) is represented by any one of the following formulas (b-1) to (b-4). 【Transformation 3】

6. The liquid crystal alignment agent according to any one of claims 1 to 5, wherein the tetracarboxylic acid derivative component includes a tetracarboxylic acid dianhydride represented by the following formula (2). 【Chemistry 4】 (In equation (2), X represents a structure selected from the group consisting of the following equations (x-1) to (x-17) and the following equations (xr-1) to (xr-2).) 【Transformation 5】 【Transformation 6】 (In formula (x-1), R １ to R ４ each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 6 carbon atoms, an alkyloxycarbonyl group having 2 to 6 carbon atoms, or a phenyl group. In formula (x-7), R ５ and R ６ each independently represents a hydrogen atom or a methyl group. In formulas (xr-1) to (xr-2), j and k are integers of 0 or 1, and A １ and A ２ each independently represents a single bond, -O-, -CO-, -COO-, a phenylene group, a sulfonyl group, or an amide group. The plurality of A ２ in formula (xr-2) may be the same or different from each other. *1 is a bond that binds to one acid anhydride group, and *2 is a bond that binds to the other acid anhydride group.)

7. The liquid crystal alignment agent according to claim 6, wherein the formula (x-1) is selected from the group consisting of the following formulas (x1-1) to (x1-6). 【Transformation 7】 (*1 is a bond that attaches to one acid anhydride group, and *2 is a bond that attaches to the other acid anhydride group.)

8. The liquid crystal alignment agent according to any one of claims 1 to 7, wherein the diamine component comprises a diamine represented by the following formula (3). 【Transformation 8】 (In formula (3), Ar １ and Ar １’ Each of these independently represents a benzene ring, a biphenyl structure, or a naphthalene ring, and one or more hydrogen atoms on the benzene ring, the biphenyl structure, or the naphthalene ring may be substituted with a monovalent group. １ and L １’ These independently represent a single bond, -O-, -C(=O)-, -C(=O)-O-, or -O-C(=O)-. A is -CH ２ - represents an alkylene group having 2 to 12 carbon atoms, or a divalent organic group formed by inserting at least one of the following groups between carbon atoms: -O-, -C(=O)-O-, and -O-C(=O)- between carbon atoms. Any hydrogen atom in A may be substituted with a halogen atom.

9. The liquid crystal alignment agent according to any one of claims 1 to 8, wherein the content of compound (B) is 0.1 to 30 parts by mass per 100 parts by mass of component (A).

10. A method for manufacturing a liquid crystal alignment film, comprising applying a liquid crystal alignment agent according to any one of claims 1 to 9 to a substrate, firing it, and, if necessary, irradiating the resulting film with polarized radiation.

11. The method for manufacturing a liquid crystal alignment film according to claim 10, wherein the firing temperature in the firing process is 150 to 250°C.

12. A liquid crystal alignment film formed from a liquid crystal alignment agent according to any one of claims 1 to 9.

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

14. The liquid crystal display element according to claim 13, which is driven by an IPS drive system or an FFS drive system.

15. Compounds represented by the following formulas (b-1) to (b-2). 【Chemistry 9】

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