Liquid crystal alignment agents, liquid crystal alignment films, liquid crystal display elements, compounds, and polymers

Abstract

The present invention provides: a liquid crystal alignment agent that makes it possible to obtain a liquid crystal alignment film having little variation (non-uniformity) in the twist angle of liquid crystals in the plane of the liquid crystal alignment film; a liquid crystal alignment film that is obtained from the liquid crystal alignment agent; a liquid crystal display element that uses the liquid crystal alignment film; a compound that can be used in these; and a polymer.　Provided is a liquid crystal alignment agent comprising at least one polymer (A) selected from the group consisting of: polyimide precursors which are obtained by reacting an active ester compound (B) represented by formula (1), a diamine component, and a tetracarboxylic acid derivative component that contains at least one compound selected from the group consisting of tetracarboxylic acid dianhydrides and derivatives thereof; and polyimides which are imidization products of the polyimide precursors. The polymer (A) has a group represented by formula (1A) derived from the active ester compound (B). Formula (1) (The definition of each symbol is as described in the specification.) Formula (1A) (The definition of each symbol is as described in the specification.)

Description

[Technical Field]

[0001] The present invention relates to liquid crystal alignment agents, liquid crystal alignment films, liquid crystal display elements, and compounds and polymers that can be used therein. [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. However, with the increasing performance, resolution, and size of liquid crystal display elements, various problems have become apparent, such as surface scratches on the alignment film caused by the rubbing process, dust generation, effects from mechanical forces and static electricity, and non-uniformity within the alignment surface. As an alternative alignment method to rubbing, photo-alignment methods are known, which impart liquid crystal alignment ability by irradiating with polarized radiation. 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] For liquid crystal display elements using the IPS driving method or the FFS driving method, high contrast is required. In Patent Document 2, a liquid crystal alignment agent containing a polyimide precursor or polyimide having a specific structure, which is suitable for a liquid crystal display element capable of obtaining good display characteristics even when a negative-type liquid crystal for enhancing contrast is applied, has been proposed.

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] In recent years, large-screen and high-definition liquid crystal display elements have become the mainstream, and the demand for higher quality of liquid crystal display elements has increased even more than before. In particular, as the liquid crystal display element becomes larger, a problem has occurred in that the twist angle of the liquid crystal in the plane of the liquid crystal display element varies slightly due to variations in the manufacturing process. Such variations result in non-uniform brightness in the plane when the liquid crystal display element is in a black display state, leading to a decrease in the quality of the liquid crystal display element.

[0008] For the reasons described above, the object of the present invention is to provide a liquid crystal alignment agent that can produce a liquid crystal alignment film with small variation (non-uniformity) in the twist angle of liquid crystals within the liquid crystal alignment film surface, a liquid crystal alignment film obtained from the liquid crystal alignment agent, a liquid crystal display element using the liquid crystal alignment film, and compounds and polymers that can be used therein. [Means for solving the problem]

[0009] As a result of diligent research to achieve the above objectives, the inventors of the present invention discovered that a liquid crystal alignment agent containing a polymer having a specific compound as a constituent component is extremely effective in achieving the above objectives, and thus completed the present invention.

[0010] The present invention encompasses the following embodiments. It contains a polyimide precursor obtained by reacting a tetracarboxylic acid derivative component, which includes at least one compound selected from the group consisting of tetracarboxylic dianhydrides and their derivatives, with a diamine component and an active ester compound (B) represented by the following formula (1), and one or more polymers (A) selected from the group consisting of polyimides, which are imidized products of the polyimide precursor. The polymer (A) has a group represented by the following formula (1A) derived from the active ester compound (B), Liquid crystal alignment agent. [ka] (W represents an organic group having a protected amino moiety selected from the group consisting of *1-NH(Boc), *1-N(Boc)2, and "*1-N(Boc)-*1)" (*1 represents a bond attached to a carbon atom), and having 1 to 30 carbon atoms excluding the Boc group. Boc represents a tert-butoxycarbonyl group.) R represents an active ester-forming group. However, if R represents a group derived from N-hydroxysuccinimide, W has two or more of the above-mentioned protective amino moieties. [ka] (W is equivalent to equation (1). * represents a bond that connects to the polymer.) [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 small variation (non-uniformity) in the twist angle of liquid crystals within the liquid crystal alignment film surface, a liquid crystal alignment film obtained from the liquid crystal alignment agent, a liquid crystal display element using the liquid crystal alignment film, and compounds and polymers that can be used therein. The mechanism by which the above effects are obtained by this invention is not entirely clear, but the following is considered to be one of the contributing factors. The active ester compound (B) reacts with the polymer ends, resulting in a highly hydrophobic polymer with protective amino groups introduced at the ends. When different types of polymers are mixed, the polymer with the introduced protective amino groups tends to be unevenly distributed on the film surface, thus enabling the production of a liquid crystal alignment film with improved orientation uniformity. Furthermore, the reaction of the active ester compound (B) with the polymer ends protects the polymer ends. As a result, the decrease in polymer molecular weight due to amide exchange that occurs during film firing is suppressed, which is thought to be the reason why a liquid crystal alignment film with high orientation uniformity can be obtained. [Modes for carrying out the invention]

[0012] The following describes in detail a liquid crystal alignment agent containing a specific polymer, 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 polymer (A) (hereinafter also referred to as polyimide polymer (A)). Polymer (A) is one or more selected from the group consisting of polyimide precursors and polyimides which are imidized products of the polyimide precursors. The polyimide precursor in polymer (A) is obtained by reacting a tetracarboxylic acid derivative component, a diamine component, and the above-mentioned active ester compound (B). 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). Polymer (A) has a group represented by the above formula (1A) derived from the active ester compound (B). 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. Furthermore, the polymer (A) itself is also a subject of this invention, independently of the liquid crystal alignment agent of the present invention.

[0014] <<Polyimide polymer (A)>> When the above polyimide polymer (A) is polyamic acid, the polyimide polymer (A) can be obtained, for example, by polymerizing (polycondensing) a tetracarboxylic acid derivative component containing tetracarboxylic dianhydride, a diamine component, and an active ester compound (B). Alternatively, a tetracarboxylic acid derivative component containing tetracarboxylic dianhydride and a diamine component may be reacted to obtain a polymer solution containing unmodified polyamic acid, and then the active ester compound (B) may be added to the polymer solution to prepare the polyamic acid that will become the polyimide polymer (A). 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. 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.

[0016] 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. 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.

[0017] Among the above aromatic tetracarboxylic dianhydrides, acyclic aliphatic tetracarboxylic dianhydrides, or alicyclic tetracarboxylic dianhydrides, tetracarboxylic dianhydrides represented by the following formula (2) are preferred.

[0018] [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).)

[0019] [ka] [ka] (In formula (x-1), R 1 ~R 4 Each 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).

[0022] [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.)

[0023] Preferred specific examples of the above equations (xr-1) and (xr-2) include the following equations (xr-3) to (xr-18).

[0024] [ka]

[0025] [ka] (In the above formula, * represents a bond that connects to the acid anhydride group.)

[0026] 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.

[0027] <<<Activated ester compound (B)>>> The polyimide polymer (A) of the present invention is obtained by using the active ester compound (B) represented by the above formula (1). By adopting this configuration, it is possible to provide a function that reduces the variation (non-uniformity) of the twist angle when used as a liquid crystal display element. Furthermore, the active ester compound (B) itself is also a subject of the present invention, independently of the liquid crystal alignment agent of the present invention.

[0028] In formula (1) above, R represents an active ester-forming group. Here, "active ester-forming group" refers to a chemical group that, together with the carbonyl group to which it is bound, forms an ester that activates the carbonyl group in a coupling reaction with an amino group-containing compound that forms an amide group, or in other coupling reactions.

[0029] Examples of active ester-forming groups include hydroxy compounds such as 1-hydroxybenzotriazole (HOBt), 1-hydroxy-7-azabenzotriazole (HOAt), N-hydroxysuccinimide (HOSu), 2-cyano-2-(hydroxyimino)ethyl acetate (oxyma), 3,4-dihydro-3-hydroxy-4-oxo-1,2,3-benzotriazine (HOOBt or HODhbt), N-hydroxy-5-norbornene-2,3-dicarboximide (HONB), 2,3,4,5,6-pentafluorophenol (HOPfp), or 6-chloro-1-hydroxy-1H-benzotriazole (Cl-HOBt), from which the hydroxyl group has been removed (see, for example, Watanabe Chemical's catalog, Amino acids and chiral building blocks to new medicine; hereinafter, these will be collectively referred to as hydroxy compounds (Ae)). Among these, from the viewpoint of suitably obtaining the effects of the present invention, HOBt, HOAt, HOSu, or a group obtained by removing a hydroxyl group from HOBt is preferred, and a group obtained by removing a hydroxyl group from HOBt, HOAt, or HOBt is more preferred. Furthermore, when the active ester-forming group represents a group derived from HOSu, W has two or more of the aforementioned protective amino moieties. Since the active ester derived from HOSu is thought to be relatively unresponsive to polymer ends, sufficient effect can be obtained by introducing two or more protective amino groups in this case.

[0030] In formula (1) above, W represents an organic group having one or more protected amino moieties selected from the group consisting of *1-NH(Boc), *1-N(Boc)2, and "*1-N(Boc)-*1)" (*1 represents a bond attached to a carbon atom), and having 1 to 30 carbon atoms excluding the Boc group. If there are two or more protected amino moieties, each protected amino moiety may be the same or different. From the viewpoint of suitably obtaining the effects of the present invention, the number of protective amino moieties is preferably one or more, and from the viewpoint of the effect of liquid crystal alignment, the number of protective amino moieties is preferably four or less. In W, the organic group having 1 to 30 carbon atoms, excluding the Boc group mentioned above, is preferably an organic group having 1 to 12 carbon atoms, and more preferably an organic group having 1 to 6 carbon atoms. Specifically, W refers to a group obtained by removing the carboxyl group from a carboxylic acid represented by "W-COOH" (where W is synonymous with formula (1); hereafter also referred to as carboxylic acid (W)). The above active ester compound (B) is synthesized, for example, from carboxylic acid (W) and the above hydroxy compound (Ae). The above carboxylic acid (W) has a group having a protected amino moiety selected from the group consisting of *1-NH(Boc), *1-N(Boc)2, and "*1-N(Boc)-*1)" (*1 represents a bond attached to a carbon atom). The above carboxylic acid (W) can be obtained, for example, by protecting the amino groups of a carboxyl group-containing polyamine (pA) having two or more amino groups, such as a carboxyl group-containing monoamine (mA) or a carboxyl group-containing diamine. Note that the protection of the amino groups may involve protecting some of the amino groups of the amine, or all of them.

[0031] Specific examples of monoamines (mA) include 1-carboxy-8-aminonaphthalene, 1-carboxy-7-aminonaphthalene, 1-carboxy-6-aminonaphthalene, 1-carboxy-5-aminonaphthalene, 1-carboxy-4-aminonaphthalene, 1-carboxy-3-aminonaphthalene, 1-carboxy-2-aminonaphthalene, 1-amino-7-carboxynaphthalene, 2-carboxy-7-aminonaphthalene, 2-carboxy-6-aminonaphthalene, and 2-carboxy-5-aminonaphthalene. Aromatic monoamines such as 2-carboxy-4-aminonaphthalene, 2-carboxy-3-aminonaphthalene, 1-amino-2-carboxynaphthalene, 2-aminonicotinic acid, 4-aminonicotinic acid, 5-aminonicotinic acid, 6-aminonicotinic acid, 3-amino-o-toluic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, or 4-aminobenzoic acid; and aliphatic monoamines such as glycine, alanine, methionine, isoleucine, norleucine, phenylalanine, or proline.

[0032] Specific examples of polyamines (pA) include diaminobenzoic acids such as 3,5-diaminobenzoic acid; carboxybiphenyl compounds such as 4,4'-diaminobiphenyl-3-carboxylic acid; carboxydiphenyl alkanes such as 4,4'-diaminodiphenylmethane-3-carboxylic acid or 4,4'-diaminodiphenylethane-3-carboxylic acid; aromatic polyamines represented by carboxydiphenyl ethers such as 4,4'-diaminodiphenyl ether-3-carboxylic acid or 4,4'-diaminodiphenyl ether-3-carboxylic acid; and aliphatic polyamines such as arginine, lysine, ornithine, or histidine.

[0033] From the viewpoint of suitably obtaining the effects of the present invention, the above-mentioned carboxylic acid (W), monoamine (mA), and polyamine (pA) are preferably those having a nitrogen atom-containing heterocycle or a derivative thereof. Specific examples of the nitrogen atom-containing heterocycle include aziridine, azetidine, pyrrole, imidazole, imidazolidine, pyrrolidine, piperidine, piperazine, morpholine, pyrazole, indole, benzimidazole, or carbazole. Specific examples of derivatives of the nitrogen atom-containing heterocycle include compounds in which any hydrogen atom of the nitrogen atom-containing heterocycle is substituted by a substituent. Examples of the substituents mentioned above include linear or branched C1-C4 alkyl groups, linear or branched C1-C4 alkoxy groups, hydroxyl groups, halogen atoms, nitro groups, cyano groups, trifluoromethyl groups, -NR7R8, or -CONR7R8 groups, where R7 and R8 independently represent a hydrogen atom and a linear or branched C1-C4 alkyl group, respectively.

[0034] The active ester compound represented by formula (1) above is preferably one of the compounds represented by the following formulas (b-1) to (b-7).

[0035] [ka]

[0036] When producing the polyimide polymer (A), the proportion of the active ester compound (B) used is preferably 0.01 to 50 moles, and more preferably 0.1 to 30 moles, per 100 moles of the total diamine components used.

[0037] <<<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 Ar1’ 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 independently represents a single bond, -O-, -C(=O)-, -C(=O)-O-, or -O-C(=O)-. A represents -CH2-, an alkylene group having 2 to 12 carbon atoms, or a divalent organic group formed by inserting at least one of the groups -O-, -C(=O)-O-, and -O-C(=O)- between carbon-carbon bonds of the alkylene group. Any hydrogen atom possessed by A may be substituted with a halogen atom.)

[0038] Ar1 and Ar in the above formula (3) 1’ each 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 the monovalent group include a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, a fluoroalkenyl group having 2 to 3 carbon atoms, a fluoroalkoxy group having 1 to 3 carbon atoms, an alkyloxycarbonyl group having 2 to 3 carbon atoms, a cyano group, a nitro group, etc.

[0039] Ar1 and Ar in the above formula (3) 1’ in, the bonding position of the amino group to the benzene ring and L1 or L 1’ is preferably the 1,4-position or the 1,3-position, and 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 the 3,3'-position, and 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 the 2,6-position, and more preferably the 2,6-position. Ar1 and Ar 1’ Preferred specific examples of include a benzene ring, a biphenyl structure, and a naphthalene ring.

[0040] In formula (3) above, A represents -CH2-, or an alkylene group having 2 to 12 carbon atoms, or a divalent organic group in which at least one of the groups -O-, -C(=O)-O-, and -OC(=O)- is inserted between the carbon-carbon bonds of the alkylene group. Any hydrogen atom in A may be substituted with a halogen atom. The alkylene group having 2 to 12 carbon atoms may be linear or branched, but it is preferable that it be linear. The -O-, -C(=O)-O-, and -OC(=O)- groups inserted into the divalent organic group may be one or more. A preferred specific example of A is a linear alkylene group having 2 to 6 carbon atoms.

[0041] In the above formula (3), the base-L1-AL 1’ The following are some preferred examples of -. -(CH2) n -, -O-(CH2) n -, -O-(CH2) n -O-, -C(=O)-(CH2) n -C(=O)-, -OC(=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 -

[0042] The above base-L1-AL 1’ In a preferred example of -, n is an integer from 1 to 12, more preferably from 2 to 12, and even more preferably from 2 to 6. The sum of m1, m2 and n' is an integer from 3 to 12, preferably from 6 to 12. m1 and m2 are preferably integers from 1 to 4, and more preferably from 2 to 4, respectively. n' is preferably an integer from 1 to 6, more preferably from 2 to 6, and even more preferably from 2 to 4.

[0043] 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.

[0044] 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.

[0045] 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;

[0046] 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;

[0047] 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 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)silane Nophenoxy)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, 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-aminophenoxy Rubonyl)-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, 2-N-(4-aminophenyl)pyridine-2,5-diamine, 2-N-(5-aminopyridine-2-yl)pyridine-2,5-diamine, 2-(4-aminophenyl)-5-aminobenzimid Diamines containing heterocyclic compounds such as zole, 2-(4-aminophenyl)-6-aminobenzimidazole, 5-(1H-benzimidazole-2-yl)benzene-1,3-diamine, or diamines represented by the following formulas (z-1) to (z-5), or 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl-N-methylamine, N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N, Diamines having a diphenylamine structure, such as N'-dimethylbenzidine or N,N'-bis(4-aminophenyl)-N,N'-dimethyl-1,4-benzenediamine, which include 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));

[0048] 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.

[0049] [ka]

[0050] [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.

[0051] Furthermore, the D in the -N(D)- of the other diamines mentioned above is preferably a carbamate-based protecting 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.

[0052] 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.)

[0053] 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.

[0054] The liquid crystal alignment agent of the present invention may contain polymers other than polymer (A). Specific examples of other polymers include at least one polymer (Q) selected from the group consisting of a polyimide precursor obtained using a tetracarboxylic acid derivative component and a diamine component without using the active ester compound (B) represented by formula (1) above as a raw material, and a polyimide which is an imidized product of the polyimide precursor; 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. As the polymer (Q) mentioned above, from the viewpoint of increasing the voltage retention rate, at least one polymer selected from the group consisting of a polyimide precursor obtained using a diamine component containing the above-mentioned nitrogen atom-containing structure and an imidized product of the polyimide precursor (hereinafter also referred to as polyimide polymer (Q)) can be mentioned. Specific examples of poly(styrene-maleic anhydride) copolymers include SMA1000, SMA2000, SMA3000 (manufactured by Cray Valley), and GSM301 (manufactured by Gifu Cerates Manufacturing Co., Ltd.), a specific example of poly(isobutylene-maleic anhydride) copolymer is Isoban-600 (manufactured by Kuraray Co., Ltd.), and a specific example of poly(vinyl ether-maleic anhydride) copolymer is 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 preferably 10 to 90 parts by mass, and more preferably 20 to 80 parts by mass, per 100 parts by mass of polymer components contained in the liquid crystal alignment agent. In this specification, the term "polymer component" refers to the collective term for polymer (A) and other polymers other than polymer (A) contained in the liquid crystal alignment agent. If polymer (A) is the only polymer contained in the liquid crystal alignment agent, the term "polymer component" refers to polymer (A).

[0055] Examples of tetracarboxylic acid derivative components for obtaining the above-mentioned polyimide polymer (Q) include tetracarboxylic acid derivative components containing the tetracarboxylic acid dianhydride compounds exemplified in the above-mentioned polyimide polymer (A). Among the tetracarboxylic acid dianhydride compounds for obtaining the polyimide polymer (Q), 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.

[0056] <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 acid 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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, 3-hydroxyphthalic anhydride, trimellitic anhydride, 3-(3-trimethoxysilyl)propyl)-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, and 4-ethynylphthalic anhydride; dicarbonate diester compounds such as di-tert-butyl dicarbonate and diallyl dicarbonate; chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride, and nicotinic acid chloride; aniline, 2-aminophenol, and 3-aminophenone. Examples include monoamine compounds such as 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.

[0061] <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. The imidization rate of polyimide in polymer (A) of the present invention may be 20-100%, 50-99%, or 70-99%, for example, from the viewpoint of reducing the rate of label defects.

[0062] 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.

[0063] <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.).

[0064] 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.

[0065] <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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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, and N-methyl-2-pyrrolidone and γ- Examples include butyrolactone, propylene glycol monobutyl ether and diisobutyl ketone; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisopropyl 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.

[0071] 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.

[0072] 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, dibromo neopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, bisphenol A type epoxy resins such as Epicote 828 (manufactured by Mitsubishi Chemical Corporation), and Epi Bisphenol F type epoxy resins such as Coat 807 (manufactured by Mitsubishi Chemical Corporation), hydrogenated bisphenol A type epoxy resins such as YX-8000 (manufactured by Mitsubishi Chemical Corporation), biphenyl skeleton-containing epoxy resins such as YX6954BH30 (manufactured by Mitsubishi Chemical Corporation), phenol novolac type epoxy resins such as EPPN-201 (manufactured by Nippon Kayaku Co., Ltd.), (o,m,p-) cresol novolac type epoxy resins such as EOCN-102S (manufactured by Nippon Kayaku Co., Ltd.), tetrakis(glycidyloxymethyl)methane, N,N,N',N'-tetraglycidyl-1,4-phenylenediamine, N,N,N',N'-tetraglycidyl-2,2'-dimethyl-4.Compounds in which a tertiary nitrogen atom is bonded to an aromatic carbon atom, such as 4'-diaminobiphenyl, 2,2-bis[4-(N,N-diglycidyl-4-aminophenoxy)phenyl]propane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane; N,N,N',N'-tetraglycidyl-1,2-diaminocyclohexane, N,N,N',N'-tetraglycidyl-1,3-diaminocyclohexane, N,N,N',N'-tetraglycidyl-1,4-diaminocyclohexane, bis(N,N-diglycidyl-4-aminocyclohexyl)methane, bis(N,N-diglycidyl-2-methyl-4-aminocyclohexyl)methane, bis(N,N-diglycidyl-3-methyl-4-aminocyclohexyl)methane Compounds in which a tertiary nitrogen atom is bonded to an aliphatic carbon atom, such as tan, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,4-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,3-bis(N,N-diglycidylaminomethyl)benzene, 1,4-bis(N,N-diglycidylaminomethyl)benzene, 1,3,5-tris(N,N-diglycidylaminomethyl)cyclohexane, and 1,3,5-tris(N,N-diglycidylaminomethyl)benzene; isocyanurate compounds such as triglycidyl isocyanurates (manufactured by Nissan Chemical Corporation); compounds described in paragraph

[0037] of Japanese Patent Publication No. 10-338880; and compounds described in 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)), bis[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.

[0073] 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 used. Furthermore, two or more crosslinkable compounds may be used in combination.

[0074] 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.

[0075] 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.

[0076] (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 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)).

[0077] <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.

[0078] 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.

[0079] <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 film-like material after firing is too thin, the reliability of the liquid crystal display element may decrease, so a thickness of 5 to 300 nm is preferred, and 10 to 200 nm is more preferred.

[0080] <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 (Polymer Sustained Alignment) method, 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.

[0081] 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.

[0082] 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.

[0083] Examples of the above-mentioned contact treatments include immersion treatment and spray treatment. The treatment time for 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 minute to 30 minutes is more preferable. The solvent used during 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.

[0084] 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 minute 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.

[0085] (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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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 material 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 as described below, optically active compounds (e.g., S-811 from Merck), 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]

[0090] 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.

[0091] (organic solvent) NMP:N-methyl-2-pyrrolidone BCS: Butyl cellosolve (ethylene glycol monobutyl ether)

[0092] (Tetracarboxylic acid dianhydride) [ka]

[0093] (Diamine) [ka]

[0094] (Terminal modifiers) [ka]

[0095] <Measurement of Viscosity> Using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.), with a sample volume of 1.1 mL and a cone rotor TE-1 (1°34’, R24), the measurement was carried out at a temperature of 25°C.

[0096] [Synthesis of Terminal Modifying Agent] AD-1 to AD-6 are novel compounds not disclosed in the literature etc., and the synthesis methods will be described in detail below. Incidentally, AD-7 was purchased as a commercially available product (manufactured by Merck & Co., Inc.) and used.

[0097] The products described in the following monomer synthesis examples 1 to 6 were 1 Identified by 1H-NMR analysis (the analysis conditions are as follows). Apparatus: ADVANCE III-500MHz manufactured by BRUKER Measurement solvent: Deuterated dimethyl sulfoxide (DMSO-d6) or deuterated chloroform (CDCl3) Reference substance: Tetramethylsilane (TMS) (δ 0.0 ppm for 1 1H)

[0098] The abbreviations in the present invention respectively indicate the following meanings. Boc2O: Di-tert-butyl dicarbonate THF: Tetrahydrofuran DMF: N,N-Dimethylformamide EDC: 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide BOP reagent: Benzotriazolyl-N-hydroxytri(dimethylamino)phosphonium hexafluorophosphate salt

[0099] [Synthesis of Monomer Synthesis Example 1 AD-1]

Chemical Formula

[0100] <Synthesis of AD-1> Into a flask, AD-1-1 (1.75 g, 4.96 mmol) and THF (12.3 g) were added and dissolved, EDC (1.16 g, 7.44 mmol) was added, and the mixture was stirred at room temperature (25 °C) for 30 minutes. Then, a solution of 3,4-dihydro-3-hydroxy-4-oxo-1,2,3-benzotriazine (0.816 g, 5.00 mmol) dissolved in THF (5.3 g) was added, and the mixture was stirred at room temperature (25 °C) for 15 hours. After the reaction was completed, ethyl acetate (18 g) and pure water (18 g) were added for liquid separation operation, and the organic layer was washed twice with pure water. The obtained organic layer was concentrated and vacuum dried at 40 °C to obtain AD-1 (Yield: 1.80 g, 3.62 mmol, brown solid, yield: 73%). As shown below 1 From the results of 1H-NMR, it was confirmed that this solid was AD-1. 1 1H-NMR (500 MHz) in DMSO-d6: δ (ppm) = 9.78 (s, 2H), 8.39 - 8.37 (m, 2H), 8.25 - 8.18 (m, 1H), 8.08 - 8.04 (m, 4H), 1.49 (s, 18H).

[0101] <Synthesis Example of Monomer AD-2>

Chemical Structure

[0102] <Example of Precipitator Synthesis 3: Synthesis of AD-3> [ka] In a flask, N-(tert-butoxycarbonyl)glycine (3.50 g, 20.0 mmol) and dichloromethane (35 g) were added and dissolved. EDC (3.26 g, 21.0 mmol) was added and the mixture was stirred at room temperature (25°C) for 30 minutes. Then, 3,4-dihydro-3-hydroxy-4-oxo-1,2,3-benzotriazine (3.59 g, 22.0 mmol) was added and the mixture was stirred at room temperature (25°C) for 18 hours to allow the reaction to proceed. After the reaction was complete, dichloromethane (35 g) and pure water (35 g) were added and liquid-liquid extraction was performed. The resulting organic layer was washed with saturated sodium bicarbonate aqueous solution, and the organic layer was concentrated to obtain the crude AD-3. Heptane and ethyl acetate were added to the crude layer and heated to 50°C until dissolved. The mixture was then cooled to room temperature to precipitate crystals. The crystals were filtered and vacuum-dried at 40°C to obtain AD-3 (yield: 1.41g, 4.40 mmol, white solid, yield: 22%). The results are shown below. 1 Based on the 1H-NMR results, it was confirmed that this solid is AD-3. 1 H-NMR(500MHz) in DMSO-d6:δ(ppm)=8.35-8.33(m,2H),8.22-8.20(m,1H),8.05-8.04(m,1H),7.60(s,1H),4.30-4.22(m,2H)1.41(s,9H).

[0103] <Monomer Synthesis Example 4: Synthesis of AD-4> [ka] N,N'-di-tert-butoxycarbonylhistidine (17.7 g, 49.8 mmol), triethylamine (6.28 g, 62.1 mmol), and dichloromethane (247 g) were added to a flask, and the resulting solution was cooled to 2°C. Furthermore, BOP reagent (22.1 g, 50.0 mmol) was added to the flask, and the mixture was stirred at 10°C for 1 hour to allow the reaction to proceed. After the reaction, the precipitated crystals were filtered off, and the solid was washed twice with 2-propanol (70.0 g) and twice with acetonitrile (70.0 g). The resulting wet product was vacuum-dried at 40°C to obtain AD-4 (yield: 8.31 g, 17.6 mmol, properties: white solid, yield: 35%). The following details are provided.1 Based on the 1H-NMR results, it was confirmed that this solid is AD-4. 1 H-NMR(500MHz) in CDCl3:δ(ppm)=8.09(d,1H,J=1.0Hz),8.03(d,1H,J=8.4Hz),7.61(d,1H,J=8.3Hz),7.52(t,1H,J=7.2Hz),7.41(t,1 H,J=8.0Hz),7.38(s,1H),6.18(d,1H,J=7.0Hz),4.99(q,1H,J=6.7Hz),3.39-3.25(m,2H),1.63(s,9H),1.48(s,9H).

[0104] <Monomer Synthesis Example 5: Synthesis of AD-5> [ka] In a flask, 4-(tert-butoxycarbonylamino)benzoic acid (5.12 g, 21.6 mmol) was dissolved in DMF (51 g), and 3,4-dihydro-3-hydroxy-4-oxo-1,2,3-benzotriazine (3.88 g, 23.8 mmol) was added, and the mixture was stirred at room temperature (25°C) for 30 minutes. Then, EDC (3.52 g, 22.7 mmol) was added to the reaction mixture, and the mixture was stirred at room temperature (25°C) for 18 hours to allow the reaction to proceed. After the reaction was complete, pure water (150 g) and toluene (100 g) were added, and liquid-liquid extraction was performed. The resulting organic layer was washed with saturated sodium bicarbonate aqueous solution, and a white solid precipitated in the organic layer. This was filtered off and vacuum-dried at 40°C to obtain AD-5 (yield: 7.10 g, 18.6 mmol, yield: 86%). 1 Based on the results of 1H-NMR, it was confirmed that this solid is AD-5. 1 H-NMR(500MHz) in DMSO-d6:δ(ppm)=10.01(s,1H),8.39-8.36(m,2H),8.24-8.22(m,1H),8.16-8.14(m,2H),8.06-8.04(m,1H),7.85-7.78(m,2H),1.50(s,9H).

[0105] <Monomer Synthesis Example 6: Synthesis of AD-6> [ka] AD-6 was obtained by following the same procedure as in monomer synthesis example 5, except that 3-(tert-butoxycarbonylamino)benzoic acid was used instead of 4-(tert-butoxycarbonylamino)benzoic acid (yield: 4.70 g, 12.3 mmol, yield: 93%). The results are shown below. 1 Based on the results of 1H-NMR, it was confirmed that this solid is AD-6. 1 H-NMR(500MHz) in DMSO-d6:δ(ppm)=9.82(s,1H),8.50(s,1H),8.40-8.37(m,2H),8.25-8.22(m , 1H), 8.08-8.05(m, 1H), 7.85-7.82(m, 2H), 7.62-7.59(m, 1H), 1.50(s, 9H).

[0106] [Synthesis of polymers] <Synthesis Example 1> In a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, DA-1 (1.08 g, 9.99 mmol), DA-2 (3.66 g, 15.0 mmol), DA-3 (4.81 g, 15.0 mmol), DA-4 (3.98 g, 9.99 mmol), and NMP (132.0 g) were added, and the mixture was stirred at room temperature for 1 hour while supplying nitrogen. Subsequently, CA-1 (10.6 g, 47.2 mmol) and NMP (44.4 g) were added, and the mixture was stirred at 40°C for 12 hours to obtain a solution of polyamic acid (PAA-0) with a solid content of 12% by mass (viscosity: 440 mPa·s).

[0107] <Synthesis Example 2> A solution of polyamic acid PAA-0 (40.0 g) was weighed into a 50 mL Erlenmeyer flask containing a stirring bar, and AD-1 (1.00 g, 1.094 mmol), a terminal modifier, was added. The mixture was stirred at 40°C for 12 hours to obtain a solution of terminally modified polyamic acid (PAA-1).

[0108] <Synthesis Examples 3-8> Solutions of terminally modified polyamic acids (PAA-2) to (PAA-7) were obtained using the same procedure as in Synthesis Example 2, except that 1.094 mmol each of AD-2 to AD-7 were added instead of AD-1 as terminal modifiers.

[0109] <Synthesis Example 9> In a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, DA-5 (1.59 g, 7.98 mmol), DA-6 (0.790 g, 2.65 mmol), DA-7 (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-2 (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-B1) with a solid content of 12% by mass (viscosity: 390 mPa·s).

[0110] [Preparation of sample solution] <Comparative Example 1> In a 50 mL Erlenmeyer flask containing a stirring bar, 1.50 g of the polyamic acid (PAA-0) solution obtained in Synthesis Example 1 was weighed out, and 3.50 g of the polyamic acid (PAA-B1) solution obtained in Synthesis Example 9 was added. Further additions of NMP (2.00 g) and BCS (3.00 g) were made, and the mixture was stirred overnight with a magnetic stirrer to obtain the liquid crystal alignment agent (AL-C1).

[0111] <Examples 1-7> Liquid crystal alignment agents (AL-1) to (AL-7) were obtained using the same procedure as in Comparative Example 1, except that 1.50 g each of (PAA-1) to (PAA-7) was used instead of polyamic acid (PAA-0). The sample solutions prepared above are summarized in Table 1 below.

[0112] [Table 1]

[0113] [Fabrication of liquid crystal cells] A liquid crystal cell with an FFS mode liquid crystal display element configuration was fabricated. First, a substrate with electrodes was prepared. The substrate was a rectangular 35mm x 40mm glass substrate with a thickness of 0.7mm. On the substrate, an ITO electrode (thickness: 50nm, electrode width: 20mm vertically, 10mm 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 second layer SiN film had a thickness of 300nm, which functions as an interlayer insulating film. On top of the second layer SiN film, a comb-shaped pixel electrode formed by patterning the ITO film was placed as the third layer, forming two pixels, the first and second pixels, each with a size of 10mm vertically and approximately 5mm 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. 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. Next, the liquid crystal alignment agents AL-C1 and AL-1 to AL-7 obtained in Comparative Example 1 and Examples 1 to 7 were filtered through a filter with a pore size of 1.0 μm, and then applied by spin coating to the surface of the electrode-equipped substrate (first glass substrate) prepared above, and to the surface of a glass substrate (second glass substrate) having a columnar spacer with a height of 4 μm on which an ITO film was deposited on the back surface. Then, after drying on a hot plate at 80°C for 2 minutes, the mixture was baked in an IR oven at 230°C for 30 minutes to form a coating film with a thickness of 100 nm. Linearly polarized ultraviolet light with a wavelength of 254 nm and an extinction ratio of 26:1 was applied to this coating film surface at a rate of 500 mJ / cm² via a polarizing plate. 2The substrates were irradiated and subjected to alignment treatment, and then baked in an IR oven at 230°C for 30 minutes to obtain a substrate with a liquid crystal alignment film. The liquid crystal alignment film formed on the electrode substrate was oriented so that the direction dividing the inner angle of the pixel bending portion was perpendicular to the orientation direction of the liquid crystal. The liquid crystal alignment film formed on the second glass substrate was oriented so that when the liquid crystal cell was fabricated, the orientation direction of the liquid crystal on the first glass substrate and the orientation direction of the liquid crystal on the second glass substrate coincided. The two substrates were made into a pair, and a sealant (XN-1500T manufactured by Mitsui Chemicals, Inc.) was printed around the periphery, leaving a liquid crystal injection port, and the other substrate was bonded to it so that the orientation direction of the liquid crystal alignment film surfaces facing each other was 0°. After that, the sealant was heat-treated at 150°C for 60 minutes to cure and create an empty cell. Liquid crystal MLC-3019 (manufactured by Merck, Inc.) 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. Subsequently, the obtained liquid crystal cells were heated at 120°C for 1 hour, left overnight, and then used for evaluation.

[0114] [Evaluation of in-plane contrast uniformity] The variation in the twist angle of liquid crystal cells was evaluated using the AxoStep high-precision Müller matrix imaging polarimeter manufactured by AXOMETRICS. The liquid crystal cells fabricated as described above were placed on a measurement stage, and the distribution of circular retardance within the pixel plane was measured without applying voltage, and 3σ, which is three times the standard deviation σ, was calculated. In-plane uniformity is considered to be better the smaller this value of 3σ is. As evaluation criteria, a 3σ value of 1.50 or less was marked "◎", a value greater than 1.50 and less than or equal to 2.00 was marked "○", and a value greater than 2.00 was marked "×". The evaluation results for the in-plane uniformity of contrast in Comparative Example 1 and Examples 1 to 7 are shown in Table 2 below.

[0115] [Table 2]

[0116] As shown in Table 2, the liquid crystal alignment films obtained using the liquid crystal alignment agents AL-1 to AL-7 of Examples 1 to 7, which contain polyamic acids modified with end-modifiers AD-1 to AD-7, showed better in-plane contrast uniformity compared to the liquid crystal alignment film obtained using the liquid crystal alignment agent AL-C1 of Comparative Example 1, which does not contain end-modified polyamic acids. [Industrial applicability]

[0117] 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.

[0118] Furthermore, the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2021-170564, filed on October 18, 2021, are incorporated herein by reference as disclosure of the specification of the present invention.

Claims

1. The material contains a polyimide precursor obtained by reacting a tetracarboxylic acid derivative component, which includes at least one compound selected from the group consisting of tetracarboxylic dianhydrides and their derivatives, with a diamine component and an active ester compound (B) represented by the following formula (1), and one or more polymers (A) selected from the group consisting of polyimides, which are imidized products of the polyimide precursor. The polymer (A) has a group represented by the following formula (1A) derived from the active ester compound (B), Liquid crystal alignment agent. 【Chemistry 1】 (In equation (1), W is *1-NH(Boc), *1-N(Boc)) ２ W represents an organic group having one or more protected amino moieties selected from the group consisting of "*1-N(Boc)-*1" (where *1 represents a bond attached to a carbon atom), and having 1 to 30 carbon atoms excluding the Boc group. Boc represents a tert-butoxycarbonyl group. R represents an active ester-forming group. However, if R represents a group derived from N-hydroxysuccinimide, W has two or more of the aforementioned protected amino moieties. 【Chemistry 2】 (In formula (1A), W is equivalent to that in formula (1). * represents a bond that connects to the polymer.)

2. The liquid crystal alignment agent according to claim 1, wherein R is a group obtained by removing a hydroxyl group from a hydroxy compound selected from 1-hydroxybenzotriazole, 1-hydroxy-7-azabenzotriazole, N-hydroxysuccinimide, 2-cyano-2-(hydroxyimino)ethyl acetate, 3,4-dihydro-3-hydroxy-4-oxo-1,2,3-benzotriazine, N-hydroxy-5-norbornene-2,3-dicarboximide, 2,3,4,5,6-pentafluorophenol, and 6-chloro-1-hydroxy-1H-benzotriazole.

3. The above W is a group obtained by removing the carboxyl group from a carboxylic acid (W) represented by "W-COOH" (where W is synonymous with formula (1)). The liquid crystal alignment agent according to claim 1 or 2, wherein the carboxylic acid (W) is obtained by protecting an amino group of a carboxyl group-containing monoamine (mA) or a carboxyl group-containing polyamine (pA) having two or more amino groups.

4. The liquid crystal aligning agent according to claim 3, wherein the carboxylic acid (W), monoamine (mA), and polyamine (pA) have a nitrogen atom-containing heterocycle or a derivative thereof.

5. The liquid crystal alignment agent according to any one of claims 1 to 4, wherein the active ester compound (B) is at least one of the compounds represented by the following formulas (b-1) to (b-7). 【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 ~R ４ Each 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 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 of these independently represents a single bond, -O-, -CO-, -COO-, a phenylene group, a sulfonyl group, or an amide group. Multiple A in formula (xr-2) ２ These may be the same or different. (*1 is the bond that attaches to one acid anhydride group, and *2 is the bond that attaches 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 independently represent 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. L １ and L １’ each independently represent a single bond, -O-, -C(=O)-, -C(=O)-O-, or -O-C(=O)-. A represents -CH ２ -, an alkylene group having 2 to 12 carbon atoms, or a divalent organic group formed by inserting at least one of -O-, -C(=O)-O-, and -O-C(=O)- between carbon-carbon bonds of the alkylene group. Any hydrogen atom possessed by A may be substituted with a halogen atom.)

9. A method for manufacturing a liquid crystal alignment film, comprising applying a liquid crystal alignment agent according to any one of claims 1 to 8 to a substrate, firing it, and, if necessary, irradiating the resulting film with polarized radiation.

10. The method for manufacturing a liquid crystal alignment film according to claim 9, wherein the firing temperature in the firing process is 150 to 250°C.

11. A liquid crystal alignment film formed from a liquid crystal alignment agent according to any one of claims 1 to 8.

12. A liquid crystal display element comprising the liquid crystal alignment film described in claim 11.

13. The liquid crystal display element according to claim 12, wherein the driving method is IPS or FFS.

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