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

Abstract

A liquid crystal aligning agent which contains a polymer (A) that is obtained by a polymerization reaction of a diamine component and a tetracarboxylic acid derivative component that contains a diimide diester compound (B) represented by formula (1), wherein the polymer (A) has a group that is derived from the diimide diester compound (B) and is represented by formula (1A). In formula (1), X1 represents a tetravalent organic group that is derived from an acyclic aliphatic tetracarboxylic acid dianhydride, an alicyclic tetracarboxylic acid dianhydride or a derivative thereof; and each R independently represents a monovalent organic group having 1 to 5 carbon atoms. In formula (1A), R represents a monovalent organic group having 1 to 5 carbon atoms; and * represents a bonding hand that is bonded to X1.

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 that impart liquid crystal alignment ability by irradiating with polarized radiation are known. 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 alignment films used in liquid crystal display elements with the IPS driving method or the FFS driving method, a high alignment control force is required to suppress afterimages (hereinafter also referred to as AC afterimages) generated by long-term AC driving. In Patent Document 2, as a means for solving the above problems, a liquid crystal aligning agent containing a polyimide precursor or polyimide having a specific structure 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 requirements for higher quality of liquid crystal display elements have increased more than ever. In particular, as the liquid crystal display elements become larger, a problem has occurred in that the twist angle of the liquid crystal within the plane of the liquid crystal display element slightly varies due to variations in the manufacturing process. Such variations result in non-uniform brightness within the plane when the liquid crystal display element is in black display, leading to a decrease in the quality of the liquid crystal display element.

[0008] From the above, an object of the present invention is to provide a liquid crystal aligning agent capable of obtaining a liquid crystal aligning film with small variation (non-uniformity) in the twist angle of liquid crystal in the plane of the liquid crystal aligning film and capable of suppressing AC afterimage, a liquid crystal aligning film obtained from the liquid crystal aligning agent, a liquid crystal display element using the liquid crystal aligning film, as well as a compound and a polymer that can be used therein.

Means for Solving the Problems

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

[0010] The present invention includes the following aspects. One or more polymers (A) selected from the group consisting of a polyimide precursor obtained by subjecting a tetracarboxylic acid derivative component containing at least one compound selected from the group consisting of tetracarboxylic dianhydrides and their derivatives (excluding tetracarboxylic diimide diester compounds) and a diimide diester compound (B) represented by the following formula (1) to a polymerization reaction with a diamine component, and a polyimide which is an imidized product of the polyimide precursor, where the polymer (A) has a group represented by the following formula (1A) derived from the diimide diester compound (B), Liquid crystal aligning agent.

Chemical formula

Chemical formula

Effects of the Invention

[0011] According to the present invention, it is possible to provide a liquid crystal alignment agent that can produce a liquid crystal alignment film in which the variation (non-uniformity) of the twist angle of liquid crystals within the liquid crystal alignment film surface is small and AC afterimage can be suppressed, 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 the present invention is not entirely clear, but the following is considered to be one of the contributing factors. The portion of polymer (A) derived from the diimide diester compound (B) is less susceptible to imidization during firing, so the amount of decomposition is suppressed when irradiated with polarized ultraviolet light, and the reorientation of the polymer is thought to be improved. Furthermore, when polymers having the group represented by formula (1A) contain two or more types of polymers, an effect is exhibited that enhances the uneven distribution on the surface, which is thought to contribute to the above effects. [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). Polymer (A) is one or more selected from the group consisting of polyimide precursors and polyimides which are imidized products of the polyimide precursors. Polyimide precursors are obtained by polymerizing a tetracarboxylic acid derivative component and a diamine component. The tetracarboxylic acid derivative component includes at least one compound selected from the group consisting of tetracarboxylic dianhydrides and their derivatives (excluding tetracarboxylic diimide diester compounds; hereinafter these are collectively referred to as tetracarboxylic dianhydride compounds) and diimide diester compound (B) represented by the above formula (1). Polymer (A) has a group represented by the above formula (1A) derived from diimide diester 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] <<Polymer (A)>> When polymer (A) is a polyamic acid, polymer (A) can be obtained, for example, by polymerizing (polycondensing) a tetracarboxylic acid derivative component containing a tetracarboxylic acid dianhydride and a diimide diester compound (B) represented by formula (1) above, and a diamine component. Furthermore, the polyimide in polymer (A) can be obtained by imidizing the polyamic acid. When polymer (A) is a polyamic acid ester, it can be obtained by the method described later, and the polyimide can be obtained by imidizing the polyamic acid ester.

[0015] <<<Tetracarboxylic acid dianhydride compounds>>> The above-mentioned tetracarboxylic dianhydride compounds include, for example, aromatic tetracarboxylic dianhydrides, acyclic aliphatic tetracarboxylic dianhydrides, or alicyclic tetracarboxylic dianhydrides, or derivatives thereof. Here, aromatic tetracarboxylic dianhydrides are acidic dianhydrides obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to an aromatic ring. Acyclic aliphatic tetracarboxylic dianhydrides are acidic dianhydrides obtained by intramolecular dehydration of four carboxyl groups bonded to a chain-like hydrocarbon structure. However, they do not need to consist solely of a chain-like hydrocarbon structure; they may also have an alicyclic structure or an aromatic ring structure in part.

[0016] 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.

[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] (X represents a structure selected from the group consisting of the following equations (x-1)~(x-18) and (xr-1)~(xr-2).)

[0019] [ka] [ka] (R 1 ~R 4Each of these independently represents a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C2-C6 alkenyl group, a C2-C6 alkynyl group, a C1-C6 monovalent organic group containing a fluorine atom, a C1-C6 alkoxy group, a C2-C6 alkoxyalkyl group, a C2-C6 alkyloxycarbonyl group, or a phenyl group. 5 and R 6 Each of these independently represents either a hydrogen atom or a methyl group. In equation (x-9) [ka] This represents a single bond or a double bond. 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. Multiple A2s 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]

[0026] <<<Diimidodiester compound (B)>>> The polymer (A) of the present invention is obtained by using a tetracarboxylic acid derivative component containing a diimide diester compound (B) represented by the above formula (1). By adopting this configuration, it is possible to impart to the resulting liquid crystal alignment film high AC afterimage resistance and low variation (non-uniformity) in the twist angle when used as a liquid crystal display element. In addition, the diimide diester compound (B) itself is also a subject of the present invention, independently of the liquid crystal alignment agent of the present invention.

[0027] Examples of monovalent organic groups having 1 to 5 carbon atoms in formula (1) above include alkyl groups having 1 to 5 carbon atoms (e.g., methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, tert-butyl group, etc.), alkenyl groups having 2 to 5 carbon atoms (vinyl group, 2-propenyl group, etc.), alkynyl groups having 2 to 5 carbon atoms (2-propynyl group, etc.), heteroatom-containing groups including groups having a heteroatom between the carbon-carbon bonds of these groups, and groups in which some or all of the hydrogen atoms of the alkyl groups, alkenyl groups, alkynyl groups and heteroatom-containing groups are substituted with substituents.

[0028] Examples of heteroatom-containing groups include groups having at least one atom selected from the group consisting of oxygen, nitrogen, silicon, phosphorus, and sulfur atoms, and include -O-, -NR- (where R represents a hydrogen atom or a methyl group), -CO-, -S-, -CO-, -Si(R')(R')- (where R' independently represents an alkyl group having 1 to 3 carbon atoms), and combinations thereof. Among these, -O- is preferred.

[0029] Examples of the substituents mentioned above include halogen atoms; alkoxy groups such as methoxy, ethoxy, and propoxy groups; alkoxycarbonyl groups such as methoxycarbonyl and ethoxycarbonyl groups; alkoxycarbonyloxy groups such as methoxycarbonyloxy and ethoxycarbonyloxy groups; cyano groups, nitro groups, and hydroxyl groups.

[0030] From the viewpoint of improving liquid crystal alignment, it is preferable that R in formula (1) above is independently an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, or a group in which some or all of the hydrogen atoms of the alkyl group, alkenyl group, or alkynyl group are substituted with substituents.

[0031] In formula (1) above, X1 represents a tetravalent organic group derived from an acyclic aliphatic tetracarboxylic dianhydride or an alicyclic tetracarboxylic dianhydride or a derivative thereof. A specific example of an acyclic aliphatic tetracarboxylic dianhydride that gives the diimide diester compound (B) represented by formula (1) above is an acidic dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to a chain-like hydrocarbon structure. However, it is not necessary to consist solely of a chain-like hydrocarbon structure; it may also have an alicyclic or aromatic ring structure in part. The number of carbon atoms in the above-mentioned chain-like hydrocarbon structure is preferably 2 to 15. The chain-like hydrocarbon structure may be linear or branched, and may contain oxygen atom-containing groups (-O-, -CO-, etc.) and / or nitrogen atom-containing groups (secondary, tertiary, quaternary amines, etc.) and / or sulfur atom-containing groups (-S-, -CS-, etc.). Furthermore, the above-mentioned chain-like hydrocarbon structure may be saturated or unsaturated hydrocarbon structures. Preferred specific examples when X1 in formula (1) above represents a tetravalent organic group derived from an acyclic aliphatic tetracarboxylic dianhydride or its derivative include formulas (x-8), (x-10), or (x-12).

[0032] A specific example of an alicyclic tetracarboxylic dianhydride that gives the diimide diester compound (B) represented by formula (1) above is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to the alicyclic structure. However, none of these four carboxyl groups are bonded to an aromatic ring. Furthermore, it is not necessary to consist solely of an alicyclic structure; it may also have a chain-like hydrocarbon structure or an aromatic ring structure in part. The alicyclic structure described above preferably has 3 to 20 carbon atoms, and more preferably 4 to 20. The alicyclic structure may also contain oxygen atom-containing groups (-O-, -CO-, etc.) and / or nitrogen atom-containing groups (secondary, tertiary, or quaternary amines, etc.) and / or sulfur atom-containing groups (-S-, -CS-, etc.). Furthermore, the alicyclic structure may be either a saturated or unsaturated alicyclic structure. A preferred specific example in which X1 in formula (1) above represents a tetravalent organic group derived from an alicyclic tetracarboxylic dianhydride or a derivative thereof is given by formula (x-1).

[0033] In particular, from the viewpoint of favorably obtaining the effects of the present invention, X1 in formula (1) is preferably a tetravalent organic group derived from an acyclic aliphatic hydrocarbon group having 4 to 16 carbon atoms or a tetracarboxylic dianhydride or derivative thereof having an alicyclic aliphatic hydrocarbon group having 4 to 16 carbon atoms, and is more preferably represented by any of formulas (x-1) to (x-18).

[0034] Particularly preferred is that the diimide diester compound represented by formula (1) is one of the compounds represented by the following formulas (b-1) to (b-9).

[0035] [ka]

[0036] When producing polymer (A), the amount of diimide diester compound (B) represented by the above formula (1) used is preferably 1 mol% or more, and more preferably 5 mol% or more, relative to 1 mole of the total tetracarboxylic acid derivative component reacted with the diamine component. Furthermore, when producing polymer (A), the amount of tetracarboxylic dianhydride represented by formula (2) or its derivative used is preferably 99 mol% or less, and more preferably 95 mol% or less, relative to 1 mole of the total tetracarboxylic derivative component reacted with the diamine component.

[0037] << The method for obtaining the above-mentioned diimidediester compound (B) is described below. The method for synthesizing the diimidediester compound of the present invention is not particularly limited, but for example, one method is to synthesize it by reacting a diimide compound (DI-0) with a dicarbonate diester compound. [ka]

[0038] Dicarbonate diester compounds can be purchased from reagent companies. Examples include di-tert-butyl dicarbonate, diallyl dicarbonate, and di-tert-amyl dicarbonate, as shown in the formula below. [ka]

[0039] The reaction can be carried out in the presence of a catalyst. An example of a catalyst is 4-dimethylaminopyridine.

[0040] Although not a catalytic reaction, a method has also been reported in which sodium iodide is added to react the diimide compound with the dicarbonate diester (Journal of Chemical and Pharmaceutical Research (2016), 8(1), 510-518).

[0041] Reaction solvents include aprotic polar organic solvents (DMF (N,N-dimethylformamide), DMSO (dimethyl sulfoxide), DMAc (N,N-dimethylacetamide), NMP (N-methyl-2-pyrrolidone), etc.); ethers (Et2O (diethyl ether), i-Pr2O (diisopropyl ether), TBME (tert-butyl methyl ether), CPME (cyclopentyl methyl ether), THF (tetrahydrofuran), dioxane, etc.); and aliphatic hydrocarbons (pentane, hexane, hep The following solvents can be used: tan, petroleum ether, etc.; aromatic hydrocarbons (benzene, toluene, xylene, mesitylene, chlorobenzene, dichlorobenzene, nitrobenzene, tetralin, etc.); halogenated hydrocarbons (chloroform, dichloromethane, carbon tetrachloride, dichloroethane, etc.); lower fatty acid esters (methyl acetate, ethyl acetate, butyl acetate, methyl propionate, etc.); nitriles (acetonitrile, propionitrile, butyronitrile, etc.); alcohols (methanol, ethanol, 2-propanol, etc.). These solvents can be appropriately selected considering the ease of reaction, etc., and can be used individually or in mixtures of two or more.

[0042] The reaction temperature can preferably be selected from a range of -10°C or higher to the boiling point of the reaction solvent used. The reaction time is 0.1 to 1000 hours, more preferably 0.5 to 100 hours. The diimide diester compound (B) obtained by the above reaction is preferably purified by recrystallization or column chromatography using silica gel or the like.

[0043] Another method involves reacting a diimide compound (DI-0) with a chloroformate ester compound in the presence of a base such as triethylamine to obtain a diimide diester compound (B).

[0044] [ka]

[0045] Chloroformate ester compounds can be purchased from reagent companies. Examples include methyl chloroformate, ethyl chloroformate, allyl chloroformate, isopropyl chloroformate, propyl chloroformate, isobutyl chloroformate, butyl chloroformate, 2-methoxyethyl chloroformate, and amyl chloroformate, as shown in the formula below. [ka]

[0046] Inorganic bases such as sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium bicarbonate, potassium bicarbonate, potassium phosphate, sodium carbonate, potassium carbonate, lithium carbonate, and cesium carbonate can be used as bases; organic bases such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, dipropylamine, tripropylamine, isopropylamine, diisopropylamine, triisopropylamine, butylamine, dibutylamine, tributylamine, diisopropylethylamine, pyridine, imidazole, quinoline, colidine, pyrrolidine, piperidine, morpholine, and N-methylmorpholine can be used.

[0047] Suitable reaction solvents include water, aprotic polar organic solvents (DMF, DMSO, DMAc, NMP, etc.), ethers (Et2O, i-Pr2O, TBME, CPME, THF, dioxane, etc.), aliphatic hydrocarbons (pentane, hexane, heptane, petroleum ether, etc.), aromatic hydrocarbons (benzene, toluene, xylene, mesitylene, chlorobenzene, dichlorobenzene, nitrobenzene, tetralin, etc.), halogenated hydrocarbons (chloroform, dichloromethane, carbon tetrachloride, dichloroethane, etc.), lower fatty acid esters (methyl acetate, ethyl acetate, butyl acetate, methyl propionate, etc.), and nitriles (acetonitrile, propionitrile, butyronitrile, etc.). These solvents can be appropriately selected considering the ease of reaction, etc., and can be used individually or in combination of two or more.

[0048] The reaction temperature can preferably be selected from a range of -10°C or higher to the boiling point of the reaction solvent used. The reaction time is 0.1 to 1000 hours, more preferably 0.5 to 100 hours. The diimide diester compound (B) obtained by the above reaction is preferably purified by recrystallization or column chromatography using silica gel or the like.

[0049] Diimide compounds (DI-0) can be obtained by reacting tetracarboxylic dianhydride with ammonium compounds.

[0050] [ka]

[0051] Ammonium compounds can be purchased from reagent companies. Examples include ammonium chloride, ammonium acetate, hydroxylamine hydrochloride, ammonium hydroxide (ammonia water), urea, and formamide.

[0052] Any reaction solvent that is stable, inert, and does not interfere with the reaction under the given reaction conditions can be used. Suitable reaction solvents include acetic acid, aprotic polar organic solvents (DMF, DMSO, DMAc, NMP, etc.), ethers (Et2O, i-Pr2O, TBME, CPME, THF, dioxane, etc.), aliphatic hydrocarbons (pentane, hexane, heptane, petroleum ether, etc.), aromatic hydrocarbons (benzene, toluene, xylene, mesitylene, chlorobenzene, dichlorobenzene, nitrobenzene, tetralin, etc.), halogenated hydrocarbons (chloroform, dichloromethane, carbon tetrachloride, dichloroethane, etc.), lower fatty acid esters (methyl acetate, ethyl acetate, butyl acetate, methyl propionate, etc.), and nitriles (acetonitrile, propionitrile, butyronitrile, etc.). These solvents can be appropriately selected considering the ease of reaction, and can be used individually or in combination of two or more.

[0053] The reaction temperature can preferably be selected from a range of -10°C or higher to the boiling point of the reaction solvent used. The reaction time is 0.1 to 1000 hours, more preferably 0.5 to 100 hours. The diimide compound (DI-0) obtained by the above reaction is preferably purified by recrystallization or column chromatography using silica gel or the like.

[0054] <<<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] (Ar1 and Ar 1’ L1 and L1 represent a benzene ring, a biphenyl structure, or a naphthalene ring, respectively, and one or more hydrogen atoms on the benzene ring, the biphenyl structure, or the naphthalene ring may be substituted with a monovalent group. 1’ A represents a single bond, -O-, -C(=O)-, or -OC(=O)-, respectively. A represents -CH2-, 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.

[0055] In the above formula (3), Ar1 and Ar 1’ Each of these represents a benzene ring, a biphenyl structure, or a naphthalene ring. One or more hydrogen atoms on the benzene ring, biphenyl structure, or naphthalene ring may be substituted with a monovalent group, and examples of such monovalent groups include halogen atoms, C1-C3 alkyl groups, C2-C3 alkenyl groups, C1-C3 alkoxy groups, C1-C3 fluoroalkyl groups, C2-C3 fluoroalkenyl groups, C1-C3 fluoroalkoxy groups, C2-C3 alkyloxycarbonyl groups, cyano groups, nitro groups, and the like.

[0056] 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 more preferably the 1,4-position or 1,3-position, and even more preferably the 1,4-position. The bonding position of the amino group to the biphenyl structure and L1 or L 1’ is more preferably the 4,4'-position or 3,3'-position, and even more preferably the 4,4'-position. The bonding position of the amino group to the naphthalene ring and L1 or L 1’ is more preferably the 1,5-position or 2,6-position of the naphthalene ring, and even more preferably the 2,6-position.

[0057] A represents -CH2-, or an alkylene group having 2 to 12 carbon atoms, or a divalent organic group in which at least one of -O-, -C(=O)-O-, and -O-C(=O)- is inserted between the carbon-carbon bonds of the alkylene group. Any hydrogen atom possessed by A may be substituted with a halogen atom. The alkylene group having 2 to 12 carbon atoms may be linear or branched, but is preferably linear. -O-, -C(=O)-O-, and -O-C(=O)- inserted into the divalent organic group may each be one or a plurality.

[0058] Preferred specific examples of the group -L1-A-L in the above formula (3) 1’ - are given below. -(CH2) n - -O-(CH2) n - -O-(CH2) n -O- -C(=O)-(CH2) n -C(=O)- -O-C(=O)-(CH2) n -O- -O-C(=O)-(CH2) n -O-C(=O)- -O-C(=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 -

[0059] The above base-L1-AL 1’ In a preferred example of -, n is an integer from 1 to 12, more preferably an integer from 2 to 12, and even more preferably an integer from 2 to 6. m1, m2, and n' are integers whose sum is between 3 and 12, more preferably between 6 and 12. m1 and m2 are more preferably integers between 1 and 4, and even more preferably between 2 and 4, respectively. n' is more preferably an integer between 2 and 6, and even more preferably between 2 and 4, respectively.

[0060] The proportion of the diamine represented by formula (3) is preferably 1 mole or more, more preferably 10 mole or more, and even more preferably 20 mole or more, per mole of the diamine component.

[0061] Polymer (A) may contain other diamines besides the diamine described above. Examples of other diamines are listed 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 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 listed 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.

[0062] 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-methoxybenzene, 2,5-diaminotoluene, 2,6-diaminotoluene, 4-aminobenzylamine, 2-(4-aminophenyl)ethylamine, 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 2-(6-aminonaphthyl)ethylamine n, 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, 3,4'-diaminobiphenyl, 4,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'-diaminobiphenyl, 2,3'-diaminobiphenyl, 1,5-diaminonaphthalene, 1,6-diaminonaphthalene, 1,7-diaminonaphthalene, 2,5-diaminonaphthalene, 2,6-diamino Diamines having a tetracarboxylic acid diimide structure, such as naphthalene, 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, and N,N'-bis(2,2'-bis(trifluoromethyl)-4'-amino-1,1'-biphenyl-4-yl)-cyclobutane-(1,2,3,4)-tetracarboxylic acid diimide;

[0063] 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'-diamino Azobenzene, diaminotran, 4,4-diaminochalcone, or [4-[(E)-3-[2-(2,4-diaminophenyl)ethoxy]-3-oxopropa-1-enyl]phenyl]4-(4,4,4-trifluorobutoxy)benzoate, or [4-[(E)-3-[[5-amino-2-[4-amino-2-[[(E)-3-[4-[4-(4,4,4-trifluorobutoxy)benzoyl]oxyphenyl]propa Diamines having photo-directing groups, such as aromatic diamines with a cinnamate structure represented by -2-enoyl]oxymethyl]phenyl]phenyl]methoxy]-3-oxo-propa-1-enyl]phenyl]4-(4,4,4-trifluorobutoxy)benzoate; diamines having photopolymerizable groups at the termini, such as 2-(2,4-diaminophenoxy)ethyl methacrylate or 2,4-diamino-N,N-diallylaniline; diamines with radical polymerization initiator functions, such as 1-(4-(2-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylpropanone and 2-(4-(2-hydroxy-2-methylpropanoyl)phenoxy)ethyl-3,5-diaminobenzoate; diamines having amide bonds, such as 4,4'-diaminobenzanilide; diamines having urea bonds, such as 4,4'-diaminodiphenylurea; 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;

[0064] 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)benzene, 1,3-bis(4-aminophenyl)benzene, 4,4'-diaminobenzophenone, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene;2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-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'-[4,4'-propane-1,3-diylbis(piperidine-1,4-diyl)]dianiline, 4-(4-aminophenoxycarbonyl)-1-(4-aminophenyl)piperidine, 2,5-bis(4-aminophenyl)pyrrole, 4,4'-(1-methyl-1H-pyrrole-2,5-diyl)bis[benzeneamine], 1,4-bis-(4-aminophenyl)- Piperazine, 2-N-(4-aminophenyl)pyridine-2,5-diamine, 2-N-(5-aminopyridine-2-yl)pyridine-2,5-diamine, 2-(4-aminophenyl)-5-aminobenzimidazole, 2-(4-aminophenyl)-6-aminobenzimidazole, 5-(1H-benzimidazole-2-yl)benzene-1,3-diamine, or heterocyclic diamines such as those represented by the following formulas (z-1) to (z-5), or 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl-N-methylamine Diamines having a diphenylamine structure, such as N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine, or N,N'-bis(4-aminophenyl)-N,N'-dimethyl-1,4-benzenediamine, which have at least one nitrogen atom-containing structure selected from the group consisting of a heterocyclic ring containing a nitrogen atom, 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));

[0065] 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)-3-carboxylic acid, 4,4'-diaminobiphenyl-3,3'-dicarb Diamines having a carboxyl group, such as nic 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)-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) -2,3-dihydro-1,3,3-trimethyl-1H-inden-6-amine; diamines having a steroid skeleton such as cholestanyloxy-3,5-diaminobenzene, cholestanyloxy-3,5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestanyl 3,5-diaminobenzoate, cholestenyl 3,5-diaminobenzoate, lanostanyl 3,5-diaminobenzoate and 3,6-bis(4-aminobenzoyloxy)cholestane; diamines represented by the following formulas (V-1)~(V-2); 1,3-bis(3-amino Diamines having siloxane bonds, such as 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.

[0066] [ka]

[0067] [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.

[0068] In addition, the D in the -N(D)- of the other diamines mentioned above is preferably a carbamate-based organic group such as a benzyloxycarbonyl group, a 9-fluorenylmethyloxycarbonyl group, an allyloxycarbonyl group, or Boc. Boc is particularly preferred from the viewpoint of having good thermal desorption efficiency, desorption occurring at relatively low temperatures, and being discharged as a harmless gas upon desorption.

[0069] As a preferred example of the other diamines exemplified above, diamines selected from the following formulas (d-1) to (d-7) are preferred. [ka] (In formulas (d-2), (d-6), and (d-7), R represents a hydrogen atom or Boc.)

[0070] 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.

[0071] 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 that does not contain the diimide diester compound (B) represented by formula (1), and a polyimide which is an imidized product of the polyimide precursor; a polymer 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 polymer (Q), from the viewpoint of increasing voltage retention, at least one polymer (Q') selected from the group consisting of a polyimide precursor obtained using a diamine component containing the nitrogen atom-containing structure and an imidized product of the polyimide precursor is included. Specific examples of poly(styrene-maleic anhydride) copolymers include SMA1000, SMA2000, SMA3000 (manufactured by Cray Valley), and GSM301 (manufactured by Gifu Ceratek Manufacturing Co., Ltd.). Specific examples of poly(isobutylene-maleic anhydride) copolymers include Isoban-600 (manufactured by Kuraray Co., Ltd.). Specific examples of poly(vinyl ether-maleic anhydride) copolymers include Gantrez AN-139 (methyl vinyl ether maleic anhydride resin, manufactured by Ashland). Other polymers may be used individually or in combination of two or more. The content of the other polymers is more preferably 10 to 90 parts by mass, and even 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).

[0072] Examples of tetracarboxylic acid derivative components for obtaining the above polymer (Q') include tetracarboxylic acid derivative components containing the tetracarboxylic acid dianhydride compounds exemplified in polymer (A) above (however, not including the diimide diester compound (B) represented by formula (1) above). Among these, tetracarboxylic acid dianhydride represented by formula (2) above or its derivative is preferred. The amount of tetracarboxylic acid dianhydride represented by formula (2) above 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.

[0073] <Method for producing polyimide precursors> Polyamic acid, one of the polyimide precursors, can be produced by the following method. Specifically, it can be synthesized by reacting (polycondensation reaction) a tetracarboxylic acid derivative component containing a tetracarboxylic dianhydride with the above-mentioned diamine component in the presence of an organic solvent at -20 to 150°C, preferably 0 to 50°C, for 30 minutes to 24 hours, preferably 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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, 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, 3-aminophenol, 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 the 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.

[0078] <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.

[0079] Methods for obtaining polyimide by imidizing the above-mentioned polyamic acid or polyamic acid ester include thermal imidation, in which the solution of the polyamic acid or polyamic acid ester is heated directly, and catalytic imidation, 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.

[0080] <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.).

[0081] 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.

[0082] <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, 1% by mass or more is preferred, and from the viewpoint of the storage stability of the solution, 10% by mass or less is preferred.

[0083] 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, 3-butoxy-N,N-dimethylpropanamide Examples include ropanamide, N-(n-propyl)-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(tert-butyl)-2-pyrrolidone, N-(n-pentyl)-2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone, 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 solvents 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.

[0084] 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.

[0085] For example, diisopropyl ether, diisobutyl ether, diisobutylcarbinol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, 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 acetate, propylene 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 liquid crystal alignment agent coating apparatus, coating conditions, and coating environment.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] Examples of the above-mentioned crosslinkable compounds include at least one crosslinkable compound selected from the group consisting of a crosslinkable compound (c-1) having at least one substituent selected from epoxy groups, oxetanyl groups, oxazoline structures, cyclocarbonate groups, blocked isocyanate groups, hydroxyl groups, and alkoxy groups, and a crosslinkable compound (c-2) having a polymerizable unsaturated group. Preferred specific examples of the above crosslinkable compounds (c-1) and (c-2) include the following compounds: Compounds having an epoxy group include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromo neopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, and bisphenol A type epoxy resins such as Epicote 828 (manufactured by Mitsubishi Chemical Corporation). Bisphenol F type epoxy resins such as Epicote 807 (Mitsubishi Chemical Corporation), hydrogenated bisphenol A type epoxy resins such as YX-8000 (Mitsubishi Chemical Corporation), biphenyl skeleton-containing epoxy resins such as YX6954BH30 (Mitsubishi Chemical Corporation), phenol novolac type epoxy resins such as EPPN-201 (Nippon Kayaku Co., Ltd.), (o,m,p-)cresol novolac type epoxy resins such as EOCN-102S (Nippon Kayaku Co., Ltd.), tetrakis(glycidyloxymethyl)methane, N,N,N',N'-tetraglycidyl-1,4-phenylenediamine, N,N,N',N'-tetraglycidyl-2,2'-dimethyl-4.Compounds in which a tertiary nitrogen atom is bonded to an aromatic carbon atom, such as 4'-diaminobiphenyl, 2,2-bis[4-(N,N-diglycidyl-4-aminophenoxy)phenyl]propane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane; N,N,N',N'-tetraglycidyl-1,2-diaminocyclohexane, N,N,N',N'-tetraglycidyl-1,3-diaminocyclohexane, N,N,N',N'-tetraglycidyl-1,4-diaminocyclohexane, bis(N,N-diglycidyl-4-aminocyclohexyl)methane, bis(N,N-diglycidyl-2-methyl-4-aminocyclohexyl)methane, bis(N,N-diglycidyl-3-methyl-4-aminocyclohexyl) Compounds in which a tertiary nitrogen atom is bonded to an aliphatic carbon atom, such as methane, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,4-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,3-bis(N,N-diglycidylaminomethyl)benzene, 1,4-bis(N,N-diglycidylaminomethyl)benzene, 1,3,5-tris(N,N-diglycidylaminomethyl)cyclohexane, and 1,3,5-tris(N,N-diglycidylaminomethyl)benzene; isocyanurate compounds such as triglycidyl isocyanurates (manufactured by Nissan Chemical Corporation); compounds described in paragraph

[0037] of Japanese Patent Publication No. 10-338880; and compounds described in WO2017 / 170483, etc. Examples of compounds having an oxetanyl group include 1,4-bis{[(3-ethyl-3-oxetanyl)methoxy]methyl}benzene (Aronoxetane OXT-121(XDO)), di[2-(3-oxetanyl)butyl]ether (Aronoxetane OXT-221(DOX)), 1,4-bis[(3-ethyloxetan-3-yl)methoxy]benzene (HQOX), 1,3-bis[(3-ethyloxetan-3-yl)methoxy]benzene (RSOX), 1,2-bis[(3-ethyloxetan-3-yl)methoxy]benzene (CTOX), and compounds having two or more oxetanyl groups as described in paragraphs

[0170] to

[0175] of Publication No. WO2011 / 132751; Compounds having an oxazoline structure include compounds such as 2,2'-bis(2-oxazoline) and 2,2'-bis(4-methyl-2-oxazoline), polymers and oligomers having an oxazoline group such as Epocross (trade name, manufactured by Nippon Shokubai Co., Ltd.), and compounds described in paragraph

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

[0025] to

[0030] and

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

[0046] to

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

[0119] to

[0120] of WO2015 / 141598; Compounds having a hydroxyl group and / or alkoxy group include N,N,N',N'-tetrakis(2-hydroxyethyl)adipoamide, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethoxymethylphenyl)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.

[0090] The above compounds are examples of crosslinkable compounds and are not limited to these. For example, other components disclosed on pages 53

[0105] to 55

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

[0091] 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.

[0092] 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, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyl 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, N-bis(oxyethylene)-3-aminopropyltrimethoxysilane, N-bis(oxyethylene)-3-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,Examples of silane coupling agents include 4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris-(trimethoxysilylpropyl)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.

[0093] (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's method for manufacturing a liquid crystal alignment film includes, for example, applying the above-mentioned liquid crystal alignment agent to a substrate and irradiating the resulting film with 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)).

[0094] <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.

[0095] 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 application and film formation is particularly suitable.

[0096] <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 for evaporating the solvent of the liquid crystal alignment agent can be, for example, 40 to 180°C. From the viewpoint of shortening the process, it may also be performed at 40 to 150°C. The firing time is not particularly limited, but examples include 1 to 10 minutes or 1 to 5 minutes. When thermally imidizing the amic acid or amic acid ester in the polymer is performed, after the step of evaporating the solvent, a firing step can be performed at a temperature range of, for example, 150 to 300°C or 150 to 250°C. While there are no particular restrictions on the baking time, typical baking times are 5 to 40 minutes, or 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.

[0097] <Process (3)> Step (3) is a step of applying an orientation treatment to the film obtained in step (2), if applicable. That is, in vertically aligned liquid crystal display elements such as VA type or PSA mode, the formed coating can be used as is as a liquid crystal alignment film, but an orientation treatment may also be applied to the coating. The orientation treatment described here refers to a treatment that gives the film anisotropic orientation in the horizontal direction. As a method for aligning the liquid crystal alignment film, a rubbing treatment method may be used, but a photo-alignment treatment method is preferred. As a photo-alignment treatment method, the surface of the film-like material is irradiated with radiation to impart an orientation in a certain direction, and if applicable, preferably a heat treatment is performed at a temperature of 150 to 250°C to impart liquid crystal alignment properties (also called liquid crystal alignment ability). The type of radiation is not particularly limited, but ultraviolet rays, visible light, electron beams, etc. can be used, and when using ultraviolet rays or visible light, it is preferable to use light that has been polarized using a polarizer (also called a polarizing plate) (hereinafter referred to as polarized light). While it is important to use wavelengths in the ultraviolet and visible light range that trigger a reaction in the photosensitive sites within the polymer, and therefore the range is not particularly limited, ultraviolet and visible light in the range of 100 nm to 500 nm is preferred, and polarized ultraviolet light in the range of 200 nm to 400 nm is particularly preferred.

[0098] The radiation doses mentioned above range from 1 to 10,000 mJ / cm². 2 This is preferable. In particular, 100 to 5,000 mJ / cm² is preferable. 2 This is preferable. Furthermore, when irradiating with radiation, heating may be performed while irradiating in order to improve the liquid crystal alignment. The temperature during heating is not particularly limited, but is preferably 50 to 250°C. The liquid crystal alignment film produced in this manner can stably align the liquid crystal molecules in a certain direction. Furthermore, the liquid crystal alignment film obtained by the above method may be subjected to a contact treatment using a solvent, and furthermore, a heat treatment may be performed after the contact treatment.

[0099] 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 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, cyclohexyl acetate, etc. Among these, water, 2-propanol, 1-methoxy-2-propanol, or ethyl lactate are preferred in terms of versatility and solvent safety. More preferred are water, 1-methoxy-2-propanol, or ethyl lactate. The solvent can be one type or a combination of two or more types. That's fine.

[0100] Examples of the above-mentioned contact treatments include immersion treatment and spray treatment (also called atomization treatment). The treatment time for these treatments is preferably 10 seconds to 1 hour, in order to efficiently dissolve the decomposition products generated by radiation irradiation. In particular, immersion treatment for 1 to 30 minutes is preferred. Furthermore, the above-mentioned contact treatment may be performed by cooling or heating, and the preferred temperature of the solvent used during the contact treatment is 10 to 80°C. In particular, 20 to 50°C is preferred. In addition, ultrasonic treatment or the like may be performed as needed in terms of the solubility of the decomposition products.

[0101] 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 more preferably 200 to 230°C. The calcination time is preferably 10 seconds to 30 minutes, more preferably 1 to 10 minutes. The heat treatment of the irradiated coating film described above is more preferably performed at 50-300°C for 1-30 minutes, and even more preferably at 120-250°C for 1-30 minutes.

[0102] (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 lateral electric field type liquid crystal display elements such as IPS type and FFS type, from the viewpoint of obtaining good horizontal uniaxial alignment, and is particularly useful as a liquid crystal alignment film for FFS type liquid crystal display elements. Liquid crystal display elements 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 encapsulating liquid crystal within the liquid crystal cell. Specifically, the following two methods can be used.

[0103] The first method involves first arranging two substrates opposite each other with a gap (cell gap) between them so that the 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 cells partitioned by the substrate surface and the sealant, bringing it into contact with the film surface, and then the injection holes are sealed.

[0104] The second method is called the ODF (One Drop Fill) method. In this method, an ultraviolet light-curable sealant is applied to one of two substrates on which a liquid crystal alignment film has been formed, creating compartments for encapsulating liquid crystal. A liquid crystal composition equivalent to the cell volume is then dropped onto the liquid crystal alignment film surface within these compartments at regular intervals. Subsequently, the other substrate is bonded to the substrate under vacuum so that the liquid crystal alignment films face each other, and the liquid crystal composition is spread across the entire surface of the substrate and brought into contact with the film surface. Next, ultraviolet light is irradiated through a photomask to prevent light from hitting the entire substrate or the liquid crystal alignment film, and after preliminary curing, the sealant is further cured by heat treatment to obtain a liquid crystal display element.

[0105] 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. Specific examples of compounds constituting the above-mentioned nematic liquid crystals include Schiff-based liquid crystal compounds, azoxy-based liquid crystal compounds, biphenyl-based liquid crystal compounds, phenylcyclohexane-based liquid crystal compounds, ester-based liquid crystal compounds, terphenyl-based liquid crystal compounds, biphenylcyclohexane-based liquid crystal compounds, pyrimidine-based liquid crystal compounds, dioxane-based liquid crystal compounds, bicyclooctane-based liquid crystal compounds, or cubane-based liquid crystal compounds.

[0106] The liquid crystal composition can be either a positive-type or negative-type liquid crystal composition, but a negative-type liquid crystal composition is preferred because it allows for higher transmittance during operation. Typical commercially available positive-type liquid crystal compositions include ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, or MLC-7081 from Merck, or PA-1492 from DIC. Representative commercially available negative liquid crystal compositions include MLC-6608, MLC-6609, MLC-6610, MLC-6882, MLC-6886, MLC-7026, MLC-7026-000, MLC-7026-100, and MLC-7029, all manufactured by Merck.

[0107] 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]

[0108] The present invention will be further described in detail below with reference to examples, but the present invention is not limited to these. The abbreviations for the compounds and the methods for measuring each property below are as follows.

[0109] (Diamine) [ka]

[0110] (Tetracarboxylic acid dianhydride) [ka]

[0111] (Diimide diester compounds) [ka]

[0112] (Additives) [ka]

[0113] (solvent) NMP:N-methyl-2-pyrrolidone BCS: Ethylene glycol monobutyl ether

[0114] <Viscosity Measurement> The viscosity of the solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample volume of 1.1 mL, using a cone rotor TE-1 (1°34', R24) at a temperature of 25°C.

[0115] <Measuring molecular weight> The molecular weight of the polymer was measured using a room-temperature gel permeation chromatography (GPC) apparatus (GPC-101) (manufactured by Showa Denko Corporation) and columns (KD-803 and KD-805 in series) (manufactured by Showa Denko Corporation) as follows. Column temperature: 50℃ Eluent: N,N-dimethylformamide (additives: lithium bromide monohydrate (LiBr·H2O) 30 mmol / L, anhydrous crystalline phosphoric acid (o-phosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 mL / L) Flow rate: 1.0ml / min Standard samples for calibration curve creation: TSK standard polyethylene oxide (molecular weight: approximately 900,000, 150,000, 100,000, and 30,000) (manufactured by Tosoh Corporation) and polyethylene glycol (molecular weight: approximately 12,000, 4,000, and 1,000) (manufactured by Polymer Laboratory Co., Ltd.).

[0116] <Synthesis of monomers> DI-1 to DI-4 are novel compounds not yet published in the literature, and their synthesis methods are described in detail below.

[0117] The products described in the monomer synthesis examples 1 to 4 below are 1 Identified by 1H-NMR analysis (analytical conditions are as follows). Equipment: Varian NMR System 400 NB (400 MHz) Measurement solvent: DMSO-d6 Reference substance: Tetramethylsilane (TMS) (δ 0.0 ppm for 1 H)

[0118] (Monomer Synthesis Example 1: Synthesis of DI-1)

[0119] [ka]

[0120] <Synthesis of DI-1-1> Into a 2 L four-necked flask, acetic acid (AcOH, 489 g), CA-1 (61.1 g, 312 mmol), and ammonium acetate (AcNH4, 24.0 g, 312 mmol) were charged and reacted under reflux conditions in a nitrogen atmosphere for about 2 days. After completion of the reaction, pure water (1500 g) was added to the reaction solution, stirred, and the resulting precipitate was filtered off. The filtrate was washed with pure water and methanol and dried to obtain DI-1-1 (yield: 51.9 g, 267 mmol, yield: 86%, property: white crystals).

[0121] <Synthesis of DI-1> Into a 1 L four-necked flask, N,N-dimethylacetamide (DMAc, 260 g), DI-1-1 (26.0 g, 134 mmol), 4-dimethylaminopyridine (DMAP, 1.64 g, 13.4 mmol), and triethylamine (Et3N, 34.9 g, 345 mmol) were charged, and ethyl chloroformate (32.0 g, 295 mmol) was added dropwise under ice-cooling conditions in a nitrogen atmosphere. After the dropwise addition, the reaction temperature was adjusted to room temperature (25 °C) and reacted for 15 hours to consume the raw materials (slurry solution). The slurry solution was filtered, and the filtrate was washed with an excess amount of methylene chloride and dried to obtain DI-1 (yield: 11.0 g, 32.5 mmol, yield: 24%, property: light peach-colored crystals). 1 1H-NMR (400 MHz, DMSO-d6): δ (ppm) = 4.37 (q, 4H, J = 7.2 Hz), 3.52 (s, 4H), 1.30 (t, 6H, J = 7.2 Hz)

[0122] (Synthesis Example 2 of Monomer DI-2)

[0123]

Chemical Structure

[0124] <Synthesis of DI-2> Into a 2 L four-necked flask, N,N-dimethylacetamide (250 g), DI-1-1 (25.0 g, 129 mmol), and 4-dimethylaminopyridine (1.58 g, 12.9 mmol) were charged, and di-tert-butyl dicarbonate (Boc2O, 61.9 g, 284 mmol) was added dropwise under a nitrogen atmosphere at room temperature (25 °C). After the dropwise addition, the reaction was carried out at room temperature for 14 hours to disappear the raw materials. After completion of the reaction, 2-propanol (750 g) was added to the reaction solution and stirred, and the resulting precipitate was filtered off and washed with 2-propanol to obtain DI-2 (yield: 48.1 g, 122 mmol, yield: 95%, property: white crystal). 1 H-NMR (400 MHz, DMSO-d6): δ (ppm) = 3.50 (s, 4H), 1.52 (s, 18H)

[0125] (Synthesis Example of Monomer 3: Synthesis of DI-3)

[0126]

Chemical Structure

[0127] (Synthesis of DI-3) By performing the same operations as described in Monomer Synthesis Example 1 and Monomer Synthesis Example 2, DI-3 was obtained by carrying out the content of the above scheme (yield: 20.6 g, 48.7 mmol, yield: 83%, property: white crystal). 1 H-NMR (400 MHz, DMSO-d6): δ (ppm) = 3.30 - 3.01 (m, 4H), 2.05 - 2.03 (m, 4H), 1.50 - 1.49 (m, 18H)

[0128] (Synthesis Example of Monomer 3: Synthesis of DI-4)

[0129]

Chemical Structure

[0130] (Synthesis of DI-4-1) Into a 300 mL four-necked flask, acetic acid (245 g), CA-4 (14.0 g, 46.3 mmol), and ammonium acetate (21.5 g, 278 mmol) were charged and reacted under reflux conditions in a nitrogen atmosphere for about 20 hours. After the reaction was completed, pure water (150 g) was added to the reaction solution and stirred. The resulting precipitate was filtered off, and the filter cake was washed with pure water and methanol and dried to obtain DI-4-1 (yield: 6.98 g, 23.2 mmol, yield: 50%, property: white crystals).

[0131] <Synthesis of DI-4> Into a 200 mL four-necked flask, tetrahydrofuran (125 g), DI-4-1 (6.0 g, 20 mmol), and 4-dimethylaminopyridine (0.024 g, 0.2 mmol) were charged, and di-tert-butyl dicarbonate (9.6 g, 44 mmol) was added dropwise under a nitrogen atmosphere at room temperature (25 °C). After the addition, the reaction was carried out at 40 °C for 16 hours. After the reaction was completed, hexane (150 g) was added to the reaction solution and stirred. The resulting precipitate was filtered off and washed with ethyl acetate (85 g) to obtain DI-4 (yield: 4.37 g, 8.73 mmol, yield: 44%, property: white crystals). 1 1H-NMR (400 MHz, DMSO-d6): δ (ppm) = 3.01 (s, 2H), 2.72 (s, 2H), 2.62 (s, 2H), 2.60 (s, 2H), 1.99 (s, 2H), 1.52 (d, 1H, J = 13.0 Hz), 1.48 (d, 18H, J = 3.2 Hz), 1.30 (d, 1H, J = 11.0 Hz), 1.10 (d, 1H, J = 11.0 Hz), 0.79 (d, 1H, J = 12.8 Hz).

[0132] <Synthesis of Polymer> (Synthesis Example 1) In a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, DA-1 (0.357 g, 3.30 mmol), DA-2 (0.806 g, 3.30 mmol), DA-3 (0.705 g, 2.20 mmol), DA-4 (0.877 g, 2.20 mmol), and NMP (30.4 g) were added and dissolved by stirring at room temperature. Then, CA-1 (2.34 g, 10.4 mmol) was added, and NMP was further added to bring the solid content concentration to 12% by mass. The mixture was stirred at 40°C for 24 hours to obtain a polyamic acid solution (PAA-R1) (viscosity: 388 mPa·s). The number-average molecular weight of this polyamic acid was 11,244, and the weight-average molecular weight was 30,370.

[0133] (Synthesis Example 2) In a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, DA-1 (0.357 g, 3.30 mmol), DA-2 (0.806 g, 3.30 mmol), DA-3 (0.705 g, 2.20 mmol), DA-4 (0.877 g, 2.20 mmol), and NMP (30.9 g) were added and dissolved by stirring at room temperature. Then, CA-1 (1.85 g, 8.25 mmol) and CA-2 (0.431 g, 2.20 mmol) were added, and NMP was further added to bring the solid content concentration to 12% by mass. The mixture was stirred at 40°C for 24 hours to obtain a polyamic acid solution (PAA-R2) (viscosity: 349 mPa·s). The number-average molecular weight of this polyamic acid was 12,175, and the weight-average molecular weight was 30,201.

[0134] (Synthesis Example 3) In a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, DA-1 (0.324 g, 3.00 mmol), DA-2 (0.733 g, 3.00 mmol), DA-3 (0.641 g, 2.00 mmol), DA-4 (0.797 g, 2.00 mmol), and NMP (30.8 g) were added and dissolved by stirring at room temperature. Then, DI-1 (0.677 g, 2.00 mmol) was added and dissolved by stirring at 60 °C for 5 hours. After that, the mixture was cooled to 40 °C, CA-1 (1.78 g, 7.95 mmol) was added, and NMP was further added to bring the solid content concentration to 12% by mass. The mixture was stirred at 40 °C for 24 hours to obtain a polymer solution (PAA-A1) (viscosity: 227 mPa·s). The number-average molecular weight of this polymer was 10,861, and the weight-average molecular weight was 26,472. The polymer obtained above 1 ¹H-NMR measurements revealed a peak near 1.29 ppm originating from the ethyl carbamate group, which was not observed in the polymers of Synthesis Example 1 and Synthesis Example 2, and the emergence of a new amide peak between 11.00 and 8.00 ppm, suggesting that the group represented by formula (1A) derived from DI-1 has been successfully introduced.

[0135] (Synthesis Example 4) In a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, DA-1 (0.324 g, 3.00 mmol), DA-2 (0.733 g, 3.00 mmol), DA-3 (0.641 g, 2.00 mmol), DA-4 (0.797 g, 2.00 mmol), and NMP (30.8 g) were added and dissolved by stirring at room temperature. Then, DI-2 (0.789 g, 2.00 mmol) was added and dissolved by stirring at 60 °C for 5 hours. After that, the mixture was cooled to 40 °C, CA-1 (1.78 g, 7.95 mmol) was added, and NMP was further added to bring the solid content concentration to 12% by mass. The mixture was stirred at 40 °C for 24 hours to obtain a polymer solution (PAA-A2) (viscosity: 225 mPa·s). The number-average molecular weight of this polymer was 10,531, and the weight-average molecular weight was 26,987. The polymer obtained above 1¹H-NMR measurements revealed a peak originating from the t-Bu group, distinct from the 1.42 ppm peak originating from the t-Bu carbamate group of DA-4 used in the polymers of Synthesis Example 1 and Synthesis Example 2, near 1.33 ppm. Additionally, a new amide peak was observed between 11.00 and 8.00 ppm. This suggests that the group represented by formula (1A) derived from DI-2 has been successfully introduced.

[0136] (Synthesis Example 5) In a 200 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, DA-5 (6.38 g, 32.0 mmol), DA-6 (1.22 g, 8.00 mmol), and NMP (109 g) were added and stirred at room temperature until dissolved. Then, CA-3 (11.3 g, 38.3 mmol) was added, and NMP was further added until the solid content concentration reached 12% by mass. The mixture was stirred at room temperature for 24 hours to obtain polyamic acid solution (PAA-B1) (viscosity: 384 mPa·s).

[0137] <Synthesis Example 6> In a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, DA-1 (0.324 g, 3.00 mmol), DA-2 (0.733 g, 3.00 mmol), DA-3 (0.641 g, 2.00 mmol), DA-4 (0.797 g, 2.00 mmol), and NMP (30.8 g) were added and dissolved by stirring at room temperature. Then, DI-3 (0.634 g, 1.50 mmol) was added and dissolved by stirring at 60°C for 5 hours. After that, the mixture was cooled to 40°C, CA-1 (1.79 g, 8.00 mmol) was added, and NMP was further added to bring the solid content concentration to 12% by mass. The mixture was stirred at 40°C for 24 hours to obtain a polymer solution (PAA-A3) (viscosity: 56.7 mPa·s). The number-average molecular weight of this polymer was 6,432, and the weight-average molecular weight was 13,826. The polymer obtained above 1¹H-NMR measurements revealed a peak originating from the t-Bu group, distinct from the 1.42 ppm peak originating from the t-Bu carbamate group of DA-4 used in the polymers of Synthesis Example 1 and Synthesis Example 2, near 1.47 ppm. Additionally, a new amide peak was observed between 11.00 and 8.00 ppm. This suggests that the group represented by formula (1A) derived from DI-3 has been successfully introduced.

[0138] <Synthesis Example 7> In a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, DA-1 (0.324 g, 3.00 mmol), DA-2 (0.733 g, 3.00 mmol), DA-3 (0.641 g, 2.00 mmol), DA-4 (0.797 g, 2.00 mmol), and NMP (30.8 g) were added and dissolved by stirring at room temperature. Then, DI-4 (0.751 g, 1.50 mmol) was added and dissolved by stirring at 60°C for 5 hours. After that, the mixture was cooled to 40°C, CA-1 (1.79 g, 8.00 mmol) was added, and NMP was further added to bring the solid content concentration to 12% by mass. The mixture was stirred at 40°C for 24 hours to obtain a polymer solution (PAA-A4) (viscosity: 32.7 mPa·s). The number-average molecular weight of this polymer was 4,504, and the weight-average molecular weight was 9,731. The polymer obtained above 1 ¹H-NMR measurements revealed a peak originating from the t-Bu group, distinct from the 1.42 ppm peak originating from the t-Bu carbamate group of DA-4 used in the polymers of Synthesis Example 1 and Synthesis Example 2, near 1.40 ppm. Additionally, a new amide peak was observed between 11.00 and 8.00 ppm. This suggests that the group represented by formula (1A) derived from DI-4 has been successfully introduced.

[0139] [Table 1]

[0140] <Preparation of liquid crystal alignment agent> (Example 1) To the polymer solution PAA-A1 (8.33 g) obtained in Synthesis Example 3, NMP (5.67 g) and BCS (6.00 g) were added and stirred at room temperature for 2 hours to obtain liquid crystal alignment agent (V-1).

[0141] (Example 2) Liquid crystal alignment agent (V-2) was obtained by following the same procedure as in Example 1, except that the polymer solution used was changed from PAA-A1 to PAA-A2.

[0142] (Example 3) To the polymer solution PAA-A3 (10.00 g) obtained in Synthesis Example 6, NMP (14.00 g) and BCS (6.00 g) were added and stirred at room temperature for 2 hours to obtain liquid crystal alignment agent (V-3).

[0143] (Example 4) To the polymer solution PAA-A4 (10.00 g) obtained in Synthesis Example 7, NMP (14.00 g) and BCS (6.00 g) were added and stirred at room temperature for 2 hours to obtain the liquid crystal alignment agent (V-4).

[0144] (Example 5) To the polymer solution PAA-A2 (1.88 g) obtained in Synthesis Example 4, the polyamic acid solution PAA-B1 (4.39 g), NMP (3.80 g), BCS (4.80 g), a 10% by mass diluted solution of AD-1 with NMP (0.376 g), and a 1% by mass diluted solution of AD-2 with NMP (0.752 g) were added. The mixture was stirred at room temperature for 2 hours to obtain the liquid crystal alignment agent (V-5).

[0145] (Comparative Example 1) ~ (Comparative Example 2) Except for changing the polymer used from PAA-A1 to polyamic acid solutions PAA-R1 to PAA-R2, the liquid crystal alignment agents (RV-1) to (RV-2) were obtained by the same procedure as in Example 5.

[0146] Table 2 shows the specifications of the liquid crystal alignment agents obtained in Examples 1-5 and Comparative Examples 1-2. The numbers in parentheses for the polymer components represent the proportion (parts by mass) of each polymer component relative to 100 parts by mass of the total polymer components.

[0147]

Table 2

[0148] An FFS-driven liquid crystal cell was fabricated and various evaluations were performed using the liquid crystal aligning agent obtained above according to the procedure shown below.

[0149] <Configuration of FFS-driven liquid crystal cell> A liquid crystal cell having the configuration of an FFS-mode liquid crystal display element was fabricated. First, a substrate with electrodes was prepared. The substrate was a rectangular glass substrate with a size of 30 mm × 35 mm and a thickness of 0.7 mm. On the substrate, an ITO electrode with a solid pattern forming a common electrode was formed as the first layer. On the first-layer common electrode, a SiN (silicon nitride) film formed by CVD (chemical vapor deposition) was formed as the second layer. The thickness of the second-layer SiN film was 300 nm, which functions as an interlayer insulating film. On the second-layer SiN film, comb-shaped pixel electrodes formed by patterning an ITO film were arranged as the third layer, and two pixels, the first pixel and the second pixel, were formed. The size of each pixel was 10 mm in length and 5 mm in width. The substrate with electrodes had a structure in which the first-layer common electrode and the third-layer pixel electrodes were insulated by the second-layer SiN film. The third-layer pixel electrode had a comb shape in which the central part was bent at an inner angle of 160° and a plurality of electrode lines with a width of 3 μm were arranged in parallel at an interval of 6 μm. One pixel was formed by a plurality of electrode lines and had a first region and a second region with a line connecting the bent parts as a boundary. Next, the liquid crystal alignment agents (V-1) to (V-5) and (RV-1) to (RV-2) obtained in Examples 1 to 5 and Comparative Examples 1 to 2 were filtered through a filter with a pore size of 1.0 μm. The filtered liquid crystal alignment agents were then applied by spin coating to the electrode-equipped substrate (hereinafter referred to as the electrode substrate) and a glass substrate having a columnar spacer with a height of 4 μm and an ITO film deposited on its back surface (hereinafter referred to as the opposing substrate). After drying on an 80°C hot plate for 2 minutes, the substrate was baked in a 230°C hot air circulating oven for 20 minutes to form a coating with a thickness of 100 nm. The surface of this coating was irradiated with polarized ultraviolet light through a 254 nm bandpass filter and polarizer to perform an alignment treatment, and a substrate with a liquid crystal alignment film was obtained. The irradiation dose is shown in Table 3 below. The liquid crystal alignment film formed on the electrode substrate is oriented so that the direction dividing the inner angle of the pixel bending portion is perpendicular to the orientation direction of the liquid crystal. The liquid crystal alignment film formed on the opposing substrate is oriented so that the orientation direction of the liquid crystal on the electrode substrate matches the orientation direction of the liquid crystal on the opposing substrate when fabricating the liquid crystal cell. The two substrates described above were used as a pair, and a sealant (Mitsui Chemicals XN-1500T) was printed onto the substrate using a dispenser. The other substrate was then bonded to the pair so that the orientation directions of the respective liquid crystal alignment films were 0° and facing each other. The bonded substrates were then pressed together and heated in a 150°C hot air circulating oven for 60 minutes to cure the sealant and create an empty cell. Liquid crystal PA-1492 (DIC Corporation) 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. The obtained liquid crystal cell was then heated at 120°C for 1 hour, left overnight, and then used for evaluation.

[0150] <Evaluation of in-plane contrast uniformity> The variation in the twist angle of liquid crystal display elements was evaluated using AxoStep 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 better the smaller this 3σ value is. As evaluation criteria, a 3σ value of 1.10 or less was classified as "excellent," a value greater than 1.10 and less than or equal to 1.30 was classified as "good," and a value greater than 1.30 was classified as "poor." Table 3 shows the evaluation results for liquid crystal display elements using each of the liquid crystal alignment agents described in the above examples and comparative examples.

[0151] <Evaluation of liquid crystal alignment stability> This evaluation assesses the afterimage (also known as AC afterimage) that occurs when the alignment performance of the liquid crystal alignment film deteriorates during long-term AC driving. The FFS-driven liquid crystal cell fabricated as described above was subjected to an AC voltage of ±4.2V at a frequency of 60Hz for 120 hours in a constant temperature environment of 60°C. Afterward, the pixel electrode and common electrode of the liquid crystal cell were short-circuited and left at room temperature (23°C) for one day. For the liquid crystal cell subjected to the above treatment, the deviation between the orientation direction of the liquid crystal in the first region of the pixel and the orientation direction of the liquid crystal in the second region of the pixel was calculated as an angle in the voltage-free state. Specifically, the liquid crystal cell was placed between two polarizing plates arranged so that their polarization axes were orthogonal, the backlight was turned on, and the arrangement angle of the liquid crystal cell was adjusted so that the transmitted light intensity of the first region of the pixel was minimized. Then, the rotation angle required to rotate the liquid crystal cell so that the transmitted light intensity of the second region of the pixel was minimized was determined. The stability of the liquid crystal orientation can be said to be better the smaller this rotation angle value is. As evaluation criteria, a rotation angle value of less than 0.100° was classified as "Excellent," a value between 0.100° and 0.200° was classified as "Good," and a value greater than 0.200° was classified as "Poor."

[0152] Table 3 shows the evaluation results for liquid crystal display elements using each of the liquid crystal alignment agents described in the above examples and comparative examples.

[0153] [Table 3]

[0154] A comparison of Examples 1-5 and Comparative Examples 1-2 showed that liquid crystal alignment films obtained from liquid crystal alignment agents using diimidediester compounds DI-1-DI-4 exhibited higher in-plane uniformity and higher liquid crystal alignment stability compared to liquid crystal alignment films obtained from liquid crystal alignment agents composed of components that do not contain diimidediester compound (B). [Industrial applicability]

[0155] 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.

Claims

1. At least one compound selected from the group consisting of tetracarboxylic dianhydrides and their derivatives (excluding tetracarboxylic diimide diester compounds). Furthermore, it contains one or more polymers (A) selected from the group consisting of a polyimide precursor obtained by polymerizing a tetracarboxylic acid derivative component containing a diimide diester compound (B) represented by the following formula (1) with a diamine component, and a polyimide which is an imidized product of the polyimide precursor. The polymer (A) has a group represented by the following formula (1A) derived from the diimide diester compound (B), Liquid crystal alignment agent. 【Chemistry 1】 (X １ (where R represents a tetravalent organic group derived from an acyclic aliphatic tetracarboxylic dianhydride or alicyclic tetracarboxylic dianhydride or its derivatives. Each R independently represents a monovalent organic group having 1 to 5 carbon atoms.) 【Chemistry 2】 (R represents a monovalent organic group with 1 to 5 carbon atoms. * represents X) １ (Represents a coupling that joins.)

2. X in equation (1) above １ The liquid crystal aligning agent according to claim 1, wherein the tetravalent organic group is derived from a tetracarboxylic dianhydride or a derivative thereof having an acyclic aliphatic hydrocarbon group having 4 to 16 carbon atoms or an alicyclic aliphatic hydrocarbon group having 4 to 16 carbon atoms.

3. X in equation (1) above １ The liquid crystal alignment agent according to claim 1, wherein the liquid crystal alignment agent represents any of the following formulas (x-1) to (x-18). 【Transformation 3】 (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. ５ and R ６ Each of these independently represents either a hydrogen atom or a methyl group. In equation (x-9) 【Chemistry 4】 (This represents a single bond or a double bond.)

4. The liquid crystal alignment agent according to claim 1, wherein the diimide diester compound (B) is at least one of the compounds represented by the following formulas (b-1) to (b-9). 【Transformation 5】

5. The liquid crystal alignment agent according to claim 1, wherein the tetracarboxylic acid derivative component includes a tetracarboxylic dianhydride represented by the following formula (2). 【Transformation 6】 (X represents a structure selected from the group consisting of the following equations (x-1) to (x-18) and (xr-1) to (xr-2).) 【Transformation 7】 【Transformation 8】 (R １ ~R ４ each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 6 carbon atoms, an alkyloxycarbonyl group having 2 to 6 carbon atoms, or a phenyl group. R ５ and R ６ each independently represents a hydrogen atom or a methyl group. In equation (x-9) 【Chemistry 9】 This represents a single bond or a double bond. 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. 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.)

6. The liquid crystal alignment agent according to claim 5, wherein formula (x-1) is selected from the group consisting of the following formulas (x1-1) to (x1-6). 【Chemistry 10】 (*1 is a bond that attaches to one acid anhydride group, and *2 is a bond that attaches to the other acid anhydride group.)

7. The liquid crystal alignment agent according to claim 1, wherein the diamine component comprises a diamine represented by the following formula (3). 【Chemistry 11】 (Ar １ , and Ar １’ Each represents a benzene ring, a biphenyl structure, or a naphthalene ring, and one or more hydrogen atoms on the benzene ring, the biphenyl structure, or the naphthalene ring may be substituted with a monovalent group. １ and L １’ These represent a single bond, -O-, -C(=O)-, or -O-C(=O)-, respectively. A is -CH ２ - represents an alkylene group having 2 to 12 carbon atoms, or a divalent organic group formed by inserting at least one of the following groups between carbon atoms: -O-, -C(=O)-O-, and -O-C(=O)- between carbon atoms. Any hydrogen atom in A may be substituted with a halogen atom.

8. A method for manufacturing a liquid crystal alignment film, comprising applying a liquid crystal alignment agent according to any one of claims 1 to 7 to a substrate, firing it, and irradiating the resulting film with radiation.

9. The method for manufacturing a liquid crystal alignment film according to claim 8, wherein the firing temperature in the firing process is 150 to 250°C.

10. A liquid crystal alignment film formed from a liquid crystal alignment agent according to any one of claims 1 to 7.

11. A liquid crystal display element comprising the liquid crystal alignment film described in claim 10.

12. The liquid crystal display element according to claim 11, which is driven by an IPS drive system or an FFS drive system.

13. A diimide diester compound that is one of the compounds represented by the following formulas (b-1) to (b-6) and formula (b-8). 【Chemistry 12】

14. At least one compound selected from the group consisting of tetracarboxylic dianhydrides and their derivatives (excluding tetracarboxylic diimide diester compounds). Furthermore, one or more selected from the group consisting of a polyimide precursor obtained by polymerizing a tetracarboxylic acid derivative component containing a diimide diester compound represented by the following formula (1) with a diamine component, and a polyimide which is an imidized product of the polyimide precursor. Having a group represented by the following formula (1A) derived from the aforementioned diimide diester compound, Polymer. 【Chemistry 13】 (X1 represents a tetravalent organic group derived from an acyclic aliphatic tetracarboxylic dianhydride or alicyclic tetracarboxylic dianhydride or a derivative thereof. R independently represents a monovalent organic group having 1 to 5 carbon atoms.) 【Chemistry 14】 (R represents a monovalent organic group with 1 to 5 carbon atoms. * represents X) １ (Represents a coupling that joins.)

15. The polymer according to claim 14, wherein X1 in formula (1) represents a tetravalent organic group derived from a tetracarboxylic dianhydride or derivative thereof having an acyclic aliphatic hydrocarbon group having 4 to 16 carbon atoms or an alicyclic aliphatic hydrocarbon group having 4 to 16 carbon atoms.

16. The polymer according to claim 14, wherein the diimide diester compound is any of the compounds represented by the following formulas (b-1) to (b-6) and (b-8). 【Chemistry 15】

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