Liquid crystal aligning agent, liquid crystal aligning film, liquid crystal display element, compound, and polymer

Abstract

A liquid crystal alignment agent containing a polymer (A) obtained by subjecting a tetracarboxylic acid derivative component including a diimide diester compound (B) represented by the following formula (1) and a diamine component to a polymerization reaction, the polymer (A) having a group represented by the following formula (1A) derived from the diimide diester compound (B). Formula (1) (X1 represents a tetravalent organic group derived from an acyclic aliphatic tetracarboxylic dianhydride or an alicyclic tetracarboxylic dianhydride or a derivative thereof. Each of R independently represents a monovalent organic group having 1 to 5 carbon atoms.) Formula (1A) (R represents a monovalent organic group having 1 to 5 carbon atoms. * represents a bonding bond to X1.)

Description

Technical Field

[0001] This invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, a liquid crystal display element, and compounds and polymers that can be used in them. Background Technology

[0002] Previously, liquid crystal displays (LCDs) were widely used as display units in personal computers, smartphones, mobile phones, television receivers, and the like. An LCD typically includes: a liquid crystal layer sandwiched between a component 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 a thin-film transistor (TFT) that switches the electrical signals supplied to the pixel electrodes. Known driving methods for liquid crystal molecules include vertical electric field methods such as TN (Twisted Nematic) and VA (Vertical Alignment); and lateral electric field methods such as IPS (In-Plane Switching) and FFS (Fringe Field Switching).

[0003] Currently, the most widely used liquid crystal alignment film in industry is manufactured by rubbing the surface of a film formed on an electrode substrate, which is composed of polymers such as polyamic acid and / or polyimide formed by imidizing it, in one direction using a cloth such as cotton, nylon, or polyester—a process known as rubbing treatment. Rubbing treatment is a simple and highly productive method useful in industry. However, with the increasing performance, resolution, and size of liquid crystal display elements, various problems have become apparent during rubbing treatment, including surface damage, dust generation, mechanical stress, static electricity effects, and inhomogeneities within the alignment treatment surface. As an alternative to rubbing treatment, photoalignment methods, which impart alignment capabilities to liquid crystals by irradiating them with polarized radiation, are known. Regarding photoalignment methods, methods utilizing photoisomerization reactions, photocrosslinking reactions, and photodecomposition reactions have been proposed (see, for example, Non-Patent Literature 1 and Patent Literature 1).

[0004] For liquid crystal alignment films used in IPS and FFS driving liquid crystal display elements, a high alignment constraint force is required to suppress image retention (hereinafter also referred to as AC image retention) caused by long-term AC driving.

[0005] In Patent Document 2, as a method to solve the above problems, a liquid crystal alignment agent containing a polyimide precursor or polyimide having a specific structure is proposed.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 9-297313

[0009] Patent Document 2: WO2016 / 152928

[0010] Non-patent literature

[0011] Non-Patent Literature 1: "Liquid Crystal Optical Alignment Film" by Kido Waki ​​and Ichimura Functional Materials, November 1997, Vol. 17, No. 1113-22 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] In recent years, large-screen and high-definition liquid crystal display (LCD) elements have become the mainstream, leading to higher requirements for their quality. In particular, with the increasing size of LCD elements, slight unevenness in the twist angle of the liquid crystal within the element's surface can occur due to manufacturing deviations. This unevenness results in inconsistent brightness within the LCD element when displaying black, thus lowering its overall quality level.

[0014] Based on the above, the object of the present invention is to provide a liquid crystal alignment agent, 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 in them, wherein the liquid crystal alignment agent can produce a liquid crystal alignment film with small non-uniformity of the twist angle of the liquid crystal within the liquid crystal alignment film surface, and further suppresses AC image retention.

[0015] Solution for solving the problem

[0016] In order to solve the above problems, the inventors conducted in-depth research and found that liquid crystal alignment agents containing polymers with specific compounds as constituent components are extremely effective in achieving the above objectives, thus completing the present invention.

[0017] The present invention includes the following solutions.

[0018] A liquid crystal alignment agent comprising one or more polymers (A) selected from the group consisting of a polyimide precursor and an imide derivative thereof, wherein the polyimide precursor is obtained by polymerizing a tetracarboxylic acid derivative component comprising at least one compound selected from the group consisting of tetracarboxylic dianhydrides and their derivatives (excluding tetracarboxylic acid diimide diesters) and a diimide diester compound (B) represented by formula (1) below with a diamine component, wherein the polymer (A) has a group derived from the diimide diester compound (B) represented by formula (1A) below.

[0019]

[0020] (X1 represents a tetravalent organic group derived from acyclic aliphatic tetracarboxylic dianhydrides or alicyclic tetracarboxylic dianhydrides or their derivatives. R independently represents a monovalent organic group with 1 to 5 carbon atoms.)

[0021]

[0022] (R represents a monovalent organic group with 1 to 5 carbon atoms. * indicates a bond bonded to X1.)

[0023] Invention Effects

[0024] According to the present invention, a liquid crystal alignment agent, 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 in them are provided, wherein the liquid crystal alignment agent can produce a liquid crystal alignment film with small non-uniformity of the twist angle of the liquid crystal within the liquid crystal alignment film surface, and further suppresses AC image retention.

[0025] The mechanism by which the above-mentioned effects are obtained through the present invention may not be clear, but the following description is considered to be one of the reasons. It can be considered that the portion of polymer (A) derived from the diimide diester compound (B) is less prone to imidization during calcination, thus suppressing decomposition during polarized ultraviolet irradiation and improving the reorientation of the polymer. Furthermore, it can be considered that when the polymer having the group shown in formula (1A) comprises two or more polymers, it exhibits an effect of increasing the presence of bias on the surface, thus achieving the above-mentioned effects. Detailed Implementation

[0026] Hereinafter, 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 will be described in detail. The description of the necessary conditions for the construction described below is an example of one embodiment of the present invention and is not specific to these contents.

[0027] In the following description, "halogen atom" can be listed as: fluorine atom, chlorine atom, bromine atom, iodine atom, etc. "Boc" represents tert-butyloxycarbonyl, and "*" indicates the bonding position.

[0028] <Polymer (A)>

[0029] The liquid crystal alignment agent of the present invention contains polymer (A).

[0030] The polymer (A) is one or more selected from the group consisting of a polyimide precursor and a polyimide that is an imide derivative of the polyimide precursor.

[0031] The polyimide precursor is obtained by polymerizing a tetracarboxylic acid derivative component with a diamine component.

[0032] The tetracarboxylic acid derivative component comprises at least one compound selected from the group consisting of tetracarboxylic dianhydrides and their derivatives (excluding tetracarboxylic dianhydride diesters, which are also referred to as tetracarboxylic dianhydride compounds below) and the diimide diester compound (B) shown in formula (1) above.

[0033] The polymer (A) has a group derived from the diimide diester compound (B) and represented by the formula (1A) above.

[0034] Examples of polyimide precursors include: polyamic acid and polyamic ester. Examples of tetracarboxylic dianhydride derivatives include: tetracarboxylic acid dihalides, tetracarboxylic acid dialkyl esters, or tetracarboxylic acid dialkyl ester dihalides.

[0035] It should be noted that polymer (A) is independent of the liquid crystal alignment agent of the present invention, but is also the subject of the present invention.

[0036] <<Polymer (A)>>

[0037] When the polymer (A) is a polyamic acid, polymer (A) is obtained, for example, by polymerizing (condensing) a tetracarboxylic acid derivative component comprising a tetracarboxylic dianhydride and a diimide diester compound (B) as shown in formula (1) with a diamine component. Furthermore, the polyimide in the polymer (A) is obtained by imidizing the polyamic acid. Additionally, when the polymer (A) is a polyamic acid ester, it can be obtained by the method described later, by imidizing the polyamic acid ester to obtain the polyimide.

[0038] <<<Tetracarboxylic dianhydride compounds>>>

[0039] Examples of the aforementioned tetracarboxylic dianhydride compounds include aromatic tetracarboxylic dianhydrides, acyclic aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, or their derivatives. Here, aromatic tetracarboxylic dianhydrides are obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to an aromatic ring. Acyclic aliphatic tetracarboxylic dianhydrides are obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. It is not necessary for the structure to consist solely of a chain hydrocarbon; a portion of the structure may also have an alicyclic or aromatic ring structure.

[0040] Furthermore, alicyclic tetracarboxylic dianhydrides are obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to the alicyclic structure. None of these four carboxyl groups are bonded to an aromatic ring.

[0041] Furthermore, it does not need to consist solely of an alicyclic structure; it can also have a chain hydrocarbon structure or an aromatic ring structure in a portion of it.

[0042] Of the above-mentioned aromatic tetracarboxylic dianhydrides, acyclic aliphatic tetracarboxylic dianhydrides, or alicyclic tetracarboxylic dianhydrides, the tetracarboxylic dianhydride shown in formula (2) is preferred.

[0043]

[0044] (X represents the structure selected from the group consisting of the following formulas (x-1)~(x-18) and (xr-1)~(xr-2).)

[0045]

[0046] (R 1 ~R 4 Each of these can independently represent a hydrogen atom, a halogen atom, an alkyl group with 1 to 6 carbon atoms, an alkenyl group with 2 to 6 carbon atoms, an alkynyl group with 2 to 6 carbon atoms, a monovalent organic group containing a fluorine atom with 1 to 6 carbon atoms, an alkoxy group with 1 to 6 carbon atoms, an alkoxyalkyl group with 2 to 6 carbon atoms, an alkoxycarbonyl group with 2 to 6 carbon atoms, or a phenyl group. 5 and R 6 Each can be used independently to represent a hydrogen atom or a methyl group.

[0047] The following structures in equation (x-9) represent single or double bonds.

[0048]

[0049] j and k are integers of 0 or 1. A1 and A2 independently represent single bonds, -O-, -CO-, -COO-, phenylene, sulfonyl, or amide groups. Multiple A2 groups may be identical or different. *1 represents a bond bonded to the anhydride group of one group, and *2 represents a bond bonded to the anhydride group of the other group.

[0050] As a preferred specific example of the tetracarboxylic dianhydride shown in the above formula (2), X can be selected from the tetracarboxylic dianhydrides in the above formulas (x-1)~(x-8), (x-10)~(x-11) and (xr-1)~(xr-2).

[0051] Regarding the above formula (x-1), it is preferred to select from the group consisting of the following formulas (x1-1) to (x1-6).

[0052]

[0053] (*1 represents a bond bonded to the anhydride group of one acid, and *2 represents a bond bonded to the anhydride group of the other acid.)

[0054] As preferred examples of the above formulas (xr-1) and (xr-2), the following formulas (xr-3) to (xr-18) can be listed.

[0055]

[0056]

[0057] <<<Diimide Diester Compound (B)>>>

[0058] The polymer (A) of the present invention is obtained by using a tetracarboxylic acid derivative component comprising the diimide diester compound (B) shown in formula (1) above. By adopting such a method, the obtained liquid crystal alignment film can be endowed with high AC image retention resistance and low non-uniformity of the twist angle when manufacturing liquid crystal display elements.

[0059] It should be noted that the diimide diester compound (B) is independent of the liquid crystal alignment agent of the present invention, but is also the subject of the present invention.

[0060] Examples of monovalent organic groups with 1 to 5 carbon atoms in R in formula (1) above include: alkyl groups with 1 to 5 carbon atoms (e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, etc.), alkenyl groups with 2 to 5 carbon atoms (vinyl, 2-propenyl, etc.), alkynyl groups with 2 to 5 carbon atoms (2-propynyl, etc.), or heteroatom-containing groups containing heteroatoms between the carbon-carbon bonds of these groups, and groups in which some or all of the hydrogen atoms of the above alkyl, alkenyl, alkynyl and heteroatom-containing groups are replaced by substituents.

[0061] Examples of heteroatom-containing groups include those having at least one atom selected from the group consisting of oxygen, nitrogen, silicon, phosphorus, and sulfur atoms, such as -O-, -NR- (where R represents a hydrogen atom or a methyl group), -CO-, -S-, -Si(R')(R')- (where each R' independently represents an alkyl group having 1 to 3 carbon atoms), and groups formed by combining these. Among these, -O- is preferred.

[0062] Examples of substituents mentioned above include: halogen atoms; alkoxy groups such as methoxy, ethoxy, and propoxy; alkoxycarbonyl groups such as methoxycarbonyl and ethoxycarbonyl; alkoxycarbonyloxy groups such as methoxycarbonyloxy and ethoxycarbonyloxy; cyano, nitro, and hydroxyl groups.

[0063] From the viewpoint of improving the orientation of liquid crystals, R in the above formula (1) is preferably an alkyl group with 1 to 5 carbon atoms, an alkenyl group with 2 to 5 carbon atoms, an alkynyl group with 2 to 5 carbon atoms, or a group in which some or all of the hydrogen atoms of the above alkyl, alkenyl, or alkynyl groups are replaced by substituents.

[0064] In formula (1) above, X1 represents a tetravalent organic group derived from acyclic aliphatic tetracarboxylic dianhydrides or alicyclic tetracarboxylic dianhydrides or their derivatives. As a specific example of an acyclic aliphatic tetracarboxylic dianhydride providing the diimide diester compound (B) shown in formula (1) above, it is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. It is not necessary for it to consist solely of a chain hydrocarbon structure; it may also have an alicyclic or aromatic ring structure in a portion thereof.

[0065] The number of carbon atoms in the above-mentioned chain hydrocarbon structure is preferably 2 to 15. It should be noted that the chain hydrocarbon structure can be straight-chain or branched, and may contain oxygen-containing groups (-O-, -CO-, etc.) and / or nitrogen-containing groups (secondary amines, tertiary amines, quaternary amines, etc.) and / or sulfur-containing groups (-S-, -CS-, etc.). Furthermore, the above-mentioned chain hydrocarbon structure can be a saturated hydrocarbon structure or an unsaturated hydrocarbon structure.

[0066] If we list specific examples of the preferred case where X1 in the above formula (1) represents a tetravalent organic group derived from a non-cyclic aliphatic tetracarboxylic dianhydride or its derivative, we can list: the above formulas (x-8), (x-10) or (x-12).

[0067] As a specific example of an alicyclic tetracarboxylic dianhydride providing the diimide diester compound (B) shown in formula (1) above, it is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to the alicyclic structure. None of these four carboxyl groups are bonded to an aromatic ring. Furthermore, it is not necessary to consist solely of an alicyclic structure; a portion of it may also have a chain hydrocarbon structure or an aromatic ring structure.

[0068] The number of carbon atoms in the above-mentioned alicyclic structure is preferably 3 to 20, more preferably 4 to 20. It should be noted that the alicyclic structure may also include oxygen-containing groups (-O-, -CO-, etc.) and / or nitrogen-containing groups (secondary amines, tertiary amines, quaternary amines, etc.) and / or sulfur-containing groups (-S-, -CS-, etc.). Furthermore, the above-mentioned alicyclic structure can be either a saturated alicyclic structure or an unsaturated alicyclic structure.

[0069] If we list a preferred specific example of the case where X1 in the above formula (1) represents a tetravalent organic group derived from an alicyclic tetracarboxylic dianhydride or its derivative, the above formula (x-1) can be listed.

[0070] From the viewpoint of properly obtaining the effects of the present invention, X1 in formula (1) is preferably a tetravalent organic group derived from a tetracarboxylic acid dianhydride or its derivative having a noncyclic aliphatic hydrocarbon group having 4 to 16 carbon atoms or an alicyclic aliphatic hydrocarbon group having 4 to 16 carbon atoms, and more preferably any formula in formulas (x-1) to (x-18).

[0071] Particularly preferred is that the diimide diester compound represented by formula (1) above is any one of the compounds represented by formulas (b-1) to (b-9) below.

[0072]

[0073] When manufacturing polymer (A), the amount of diimide diester compound (B) shown in formula (1) above used is preferably 1 mol% or more, more preferably 5 mol% or more, relative to 1 mole of all tetracarboxylic acid derivative components that react with the diamine component.

[0074] Furthermore, when manufacturing polymer (A), the amount of tetracarboxylic acid dianhydride or its derivative shown in formula (2) above is preferably 99 mol% or less, more preferably 95 mol% or less, relative to 1 mole of all tetracarboxylic acid derivative components that react with the diamine component.

[0075] <<<<Preparation method of diimide diester compound (B)>>>>

[0076] The method for obtaining the above-mentioned diimide diester compound (B) will be described below. The method for synthesizing the diimide diester compound of the present invention is not particularly limited; for example, a method by reacting a diimide compound (DI-O) with a dicarbonate diester compound can be cited.

[0077]

[0078] Dicarbonate esters can be purchased from reagent companies. Examples include di-tert-butyl dicarbonate, diallyl dicarbonate, and di-tert-pentyl dicarbonate, all of which are shown in the following formulas.

[0079]

[0080] The reaction can be carried out in the presence of a catalyst. Examples of catalysts include 4-dimethylaminopyridine.

[0081] A method for reacting diimide compounds with dicarbonate by adding sodium iodide, which is not a catalytic reaction, was also reported (Journal of Chemical and Pharmaceutical Research (2016), 8(1), 510-518).

[0082] As reaction solvents, the following can be used: 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.). Hexacyclic hydrocarbons (e.g., hexane, heptane, petroleum ether, etc.); aliphatic hydrocarbons (pentane, hexane, heptane, petroleum ether, etc.); aromatic hydrocarbons (benzene, toluene, xylene, mesitylene, chlorobenzene, dichlorobenzene, nitrobenzene, tetrahydronaphthalene, 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, and one or more can be used alone or in combination.

[0083] The reaction temperature is preferably selected from a range of -10°C or higher up 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.

[0084] The diimide diester compound (B) obtained by the above reaction is preferably purified by recrystallization or column chromatography using silica gel or the like.

[0085] As another method, a diimide diester compound (B) can be obtained by reacting a diimide compound (DI-0) with a chloroformate compound in the presence of a base such as triethylamine.

[0086]

[0087] Chloroformate 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 pentyl chloroformate, all represented by the following formulas.

[0088]

[0089] As alkalis, the following can be used: 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; and organic bases such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, dipropylamine, tripropylamine, isopropylamine, diisopropylamine, triisopropylamine, butylamine, dibutylamine, tributylamine, diisopropylethylamine, pyridine, imidazole, quinoline, trimethylpyridine (collidine), pyrrolidine, piperidine, morpholine, and N-methylmorpholine.

[0090] As reaction solvents, the following can be used: 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, tetrahydronaphthalene, 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.). These solvents can be appropriately selected considering the ease of reaction, and one or more can be used alone or in combination.

[0091] The reaction temperature is preferably selected from a range of -10°C or higher up 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.

[0092] The diimide diester compound (B) obtained by the above reaction is preferably purified by recrystallization or column chromatography using silica gel or the like.

[0093] Diimide compounds (DI-0) can be obtained by reacting tetracarboxylic dianhydride with an ammonium compound.

[0094]

[0095] Ammonium compounds can be purchased from reagent companies. Examples include: ammonium chloride, ammonium acetate, hydroxylamine hydrochloride, ammonium hydroxide (ammonia water), urea, and formamide.

[0096] Any reaction solvent that is stable and inert under the stated reaction conditions and does not hinder the reaction 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, tetrahydronaphthalene, 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.). These solvents can be appropriately selected considering the ease of the reaction, and one or more can be used alone or in combination.

[0097] The reaction temperature is preferably selected from a range of -10°C or higher up 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.

[0098] The diimide compound (DI-0) obtained by the above reaction is preferably purified by recrystallization or column chromatography using silica gel or the like.

[0099] <<<Diamine Component>>>

[0100] The diamine component used to manufacture the polyimide precursor is not particularly limited, but it is preferred to contain a diamine component that contains the diamine shown in formula (3) below.

[0101]

[0102] (Ar1 and Ar 1’ Each represents a benzene ring, a biphenyl structure, or a naphthalene ring, wherein one or more hydrogen atoms on the benzene ring, the biphenyl structure, or the naphthalene ring are optionally substituted with monovalent groups. L1 and L 1’Each represents a single bond, -O-, -C(=O)-, or -O-C(=O)-. A represents a -CH2- group, an alkylene group having 2 to 12 carbon atoms, or a divalent organic group formed by inserting at least any group selected from -O-, -C(=O)-O-, and -O-C(=O)- between the carbon-carbon bonds of the alkylene group. Any hydrogen atom in A may optionally be replaced by a halogen atom.

[0103] Ar1 and Ar in the above formula (3) 1’ Each 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 are optionally replaced by a monovalent group. Examples of such monovalent groups include: halogen atoms, alkyl groups with 1 to 3 carbon atoms, alkenyl groups with 2 to 3 carbon atoms, alkoxy groups with 1 to 3 carbon atoms, fluoroalkyl groups with 1 to 3 carbon atoms, fluoroalkenyl groups with 2 to 3 carbon atoms, fluoroalkoxy groups with 1 to 3 carbon atoms, alkoxycarbonyl groups with 2 to 3 carbon atoms, cyano groups, nitro groups, etc.

[0104] In the above equation (3), Ar1 and Ar 1’ In, amino and L1 or L 1’ The bonding position on the benzene ring is more preferably 1,4- or 1,3-, and even more preferably 1,4-. The amino group and L1 or L... 1’ The bonding position in the biphenyl structure is more preferably at the 4,4'- or 3,3'- position, and even more preferably at the 4,4'- position. The amino group and L1 or L... 1’ The bonding position of the naphthalene ring is more preferably at the 1,5-position or the 2,6-position, and even more preferably at the 2,6-position.

[0105] A represents -CH2-, or an alkylene group having 2 to 12 carbon atoms, or a divalent organic group formed by inserting at least any group from -O-, -C(=O)-O-, and -O-C(=O)- between the carbon-carbon bonds of the alkylene group. Any hydrogen atom in A may optionally be replaced by a halogen atom.

[0106] The alkylene groups having 2 to 12 carbon atoms can be either straight-chain or branched, with straight-chain being preferred.

[0107] The -O-, -C(=O)-O-, and -O-C(=O)- inserted into the divalent organic group can each be one or more.

[0108] The following lists the groups -L1-A-L in formula (3) above. 1’ - A preferred specific example.

[0109] -(CH2) n -.

[0110] -O-(CH2) n -.

[0111] -O-(CH2) n -O-.

[0112] -C(=O)-(CH2) n -C(=O)-.

[0113] -O-C(=O)-(CH2) n -O-.

[0114] -O-C(=O)-(CH2) n -O-C(=O)-.

[0115] -O-C(=O)-(CH2) n -C(=O)-O-.

[0116] -C(=O)-O-(CH2) n -O-C(=O)-.

[0117] -(CH2) m1 -O-(CH2) n’ -O-(CH2) m2 -.

[0118] -(CH2) m1 -O-C(=O)-(CH2) n’ -C(=O)-O-(CH2) m2 -.

[0119] -(CH2) m1 -C(=O)-O-(CH2) n’ -O-C(=O)-(CH2) m2 -.

[0120] In the above group -L1-A-L 1’ In a preferred specific example, 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.

[0121] The sum of m1, m2, and n' is an integer from 3 to 12, more preferably an integer from 6 to 12. m1 and m2 are each more preferably integers from 1 to 4, and even more preferably integers from 2 to 4. n' is more preferably an integer from 2 to 6, and even more preferably an integer from 2 to 4.

[0122] The proportion of the diamine shown in formula (3) relative to 1 mole of the diamine component is preferably 1 mol% or more, more preferably 10 mol% or more, and even more preferably 20 mol% or more.

[0123] Polymer (A) may also contain other diamines besides the diamines described above. Examples of other diamines are listed below, but the present invention is not limited thereto. When other diamines are used in addition to the diamine shown in formula (3) above, the amount of the diamine shown in formula (3) relative to the diamine component is preferably 90 mol% or less, more preferably 80 mol% or less. Examples of other diamines are listed below, but the present invention is not limited thereto. The above-mentioned other diamines may be used alone or in combination of two or more.

[0124] 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, 2,2'-Dimethyl-4,4 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-diaminonaphthalene, 2,7 -Diaminonaphthalene; N,N'-bis(4-aminophenyl)-cyclobutane-(1,2,3,4)-tetracarboxylic acid diimide, N,N'-bis(4-aminophenyl)-1,3-dimethylcyclobutane-(1,2,3,4)-tetracarboxylic acid diimide, N,N'-bis(2,2'-bis(trifluoromethyl)-4'-amino-1,1'-biphenyl-4-yl)-cyclobutane-(1,2,3,4)-tetracarboxylic acid diimide, and other diamines with a tetracarboxylic acid diimide structure.

[0125] 1,4-Phenylidene bis(4-aminobenzoate), 1,4-Phenylidene bis(3-aminobenzoate), 1,3-Phenylidene bis(4-aminobenzoate), 1,3-Phenylidene bis(3-aminobenzoate), bis(4-aminophenyl) terephthalate, bis(3-aminophenyl) terephthalate, bis(4-aminophenyl) isophthalate, bis(3-aminophenyl) isophthalate; 4,4'-Diamino Benzyl azobenzene, diaminodiphenylacetylene, 4,4-diaminochalcone, or [4-[(E)-3-[2-(2,4-diaminophenyl)ethoxy]-3-oxo-prop-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]prop-2-enoyl]oxymethyl]phenyl]phenyl]methoxy]-3-oxo-prop-1-enyl]phenyl]4-(4,4,4-trifluorobutoxy)benzoate, representing aromatic diamines with cinnamic acid ester structures and other photo-oriented groups; diamines with photopolymerizable groups at the ends, such as 2-(2,4-diaminophenoxy)ethyl methacrylate or 2,4-diamino-N,N-diallyl aniline; diamines with free radical polymerization initiator functions, such as 1-(4-(2-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylacetone, 2-(4-(2-hydroxy-2-methylpropionyl)phenoxy)ethyl-3,5-diaminobenzoate; diamines with amide bonds, such as 4,4'-diaminobenzoylaniline; diamines with urea bonds, such as 4,4'-diaminodiphenylurea; H2N-Y D -NH2(Y D This refers to diamines with thermally detachable groups, such as divalent organic groups (where D represents a protecting group that is removed and replaced by a hydrogen atom upon heating).

[0126] 3,3'-Diaminodiphenyl ether, 3,4'-Diaminodiphenyl ether, 4,4'-Diaminodiphenyl ether, 4,4'-Sulfodiphenylamine, 3,3'-Sulfodiphenylamine, bis(4-aminophenyl)silane, bis(3-aminophenyl)silane, dimethyl-bis(4-aminophenyl)silane, dimethyl-bis(3-aminophenyl)silane, 4,4'-Thiodiphenylamine, 3,3'-Thiodiphenylamine, 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-Diaminodiphenylamine 3,4-Diaminopyridine, 2,4-Diaminopyrimidine, 3,6-Diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N-(3-(1H-imidazol-1-yl)propyl-3,5-diaminobenzamide, 4-[4-[(4-aminophenoxy)methyl]-4,5-dihydro-4-methyl-2-oxazolyl]-aniline, 4-[4-[(4-aminophenoxy)methyl]-4,5-dihydro-2-oxazolyl]-aniline, 1,4-bis(p-aminobenzyl)piperazine, 4,4'- [4,4'-propane-1,3-diylbis(piperidine-1,4-diyl)]diphenylamine, 4-(4-aminophenoxycarbonyl)-1-(4-aminophenyl)piperidine, 2,5-bis(4-aminophenyl)pyrrole, 4,4'-(1-methyl-1H-pyrrole-2,5-diyl)bis[aniline], 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)phenyl-1,3-diamine or The diamines represented by the following formulas (z-1) to (z-5) are heterocyclic diamines, or diamines with a diphenylamine structure such as 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl-N-methylamine, N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine, or N,N'-bis(4-aminophenyl)-N,N'-dimethyl-1,4-phenylenediamine, which have at least one nitrogen-containing structure selected from the group consisting of a heterocycle, a secondary amino group, or a tertiary amino group (excluding amino groups derived from -N(D)- (D represents a protecting group that is removed and substituted with a hydrogen atom by heating)).

[0127] 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'-dicarboxylic acid Acids, 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, and other diamines with carboxyl groups; 1-(4-aminophenyl)-1,3,3-trimethyl-1H-indane-5-amine, 1-(4-aminophenyl) Diamines with a steroidal skeleton, such as cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholesteryl ester of 3,5-diaminobenzoate, cholesteryl ester of 3,5-diaminobenzoate, cholesteryl ester of 3,5-diaminobenzoate, and lanostane of 3,6-bis(4-aminobenzoyloxy)cholestane; diamines represented by the following formulas (V-1) to (V-2); 1 Diamines containing siloxane bonds, such as 3-bis(3-aminopropyl)-tetramethyldisiloxane; acyclic aliphatic diamines such as m-phenylenediamine, 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 formed by bonding two amino groups to any of the formulas (Y-1) to (Y-167) described in WO2018 / 117239.

[0128]

[0129]

[0130] In equation (V-1), m and n are integers from 0 to 3 (where 1≤m+n≤4), j is an integer of 0 or 1, and X 1 It represents -(CH2) a - (a is an integer from 1 to 15), -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -CH2O-, -CH2-OCO-, -COO-, or -OCO-. R 1This refers to a fluorine atom, an alkyl group containing fluorine atoms with 1 to 10 carbon atoms, an alkoxy group containing fluorine atoms with 1 to 10 carbon atoms, an alkyl group with 3 to 10 carbon atoms, an alkoxy group with 3 to 10 carbon atoms, or an alkoxyalkyl group with 3 to 10 carbon atoms. In formula (V-2), X 2 Represents -O-, -CH2O-, -CH2-OCO-, -COO-, or -OCO-, R 2 This refers to alkyl groups with 3 to 30 carbon atoms, and alkyl groups containing fluorine atoms with 3 to 20 carbon atoms. In the presence of two m, n, X... 1 and R 1 In the case of each, they each independently possess the above definition.

[0131] It should be noted that the D in the -N(D)- group of the other diamines mentioned above is preferably an organic group of the carbamate system, such as benzyloxycarbonyl, 9-fluorenyloxycarbonyl, allyloxycarbonyl, or Boc. From the viewpoint of good efficiency in thermal release, release at relatively low temperatures, and release as a harmless gas during release, Boc is particularly preferred.

[0132] Preferred examples of diamines having thermally detachable groups, as exemplified by the other diamines mentioned above, are preferably selected from the diamines of the following formulas (d-1) to (d-7).

[0133]

[0134] (In formulas (d-2), (d-6), and (d-7), R represents a hydrogen atom or Boc.)

[0135] When using the aforementioned diamine with thermally detachable groups as the diamine component for manufacturing polyimide precursors, from the viewpoint of appropriately obtaining the effects of the present invention, it is preferable that the diamine component is 5 to 40 mol%, more preferably 5 to 35 mol%, and even more preferably 5 to 30 mol%, relative to 1 mole of the diamine component.

[0136] The liquid crystal alignment agent of the present invention may also contain polymers other than polymer (A). Specific examples of other polymers include polymers selected from the group consisting of: at least one polymer (Q) selected from the group consisting of a polyimide precursor obtained by using a tetracarboxylic acid derivative component and a diamine component that does not contain the diimide diester compound (B) shown in formula (1) above, and an imide as an imide of the polyimide precursor; polysiloxanes; polyesters; polyamides; polyureas; polyorganosiloxanes; cellulose derivatives; polyacetals; polystyrene derivatives; poly(styrene-maleic anhydride) copolymers; poly(isobutylene-maleic anhydride) copolymers; poly(vinyl ether-maleic anhydride) copolymers; poly(styrene-phenylmaleimide) derivatives; and poly(meth)acrylates. From the viewpoint of improving voltage retention, at least one polymer (Q') selected from the group consisting of a polyimide precursor obtained using a diamine component containing a diamine having a nitrogen-containing structure and an imide derivative of that polyimide precursor can be cited as examples of the aforementioned polymer (Q). Specific examples of poly(styrene-maleic anhydride) copolymers include: SMA1000, SMA2000, SMA3000 (manufactured by Cray Valley), GSM301 (manufactured by Gifu Shellac Manufacturing), etc. Specific examples of poly(isobutylene-maleic anhydride) copolymers include: ISOBAM-600 (manufactured by Kuraray), and specific examples of poly(vinyl ether-maleic anhydride) copolymers include: Gantrez AN-139 (methyl vinyl ether maleic anhydride resin, manufactured by Ashland).

[0137] Other polymers may be used alone, or in combination of two or more. The proportion of other polymers relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent is more preferably 10 to 90 parts by mass, and even more preferably 20 to 80 parts by mass.

[0138] It should be noted that, in this specification, "polymer component" refers to the collective term for polymer (A) contained in the liquid crystal alignment agent and other polymers besides polymer (A). When the liquid crystal alignment agent contains only polymer (A), the polymer component refers to polymer (A).

[0139] As a tetracarboxylic acid derivative component for obtaining the above polymer (Q'), examples include: a tetracarboxylic acid dianhydride compound included in the above polymer (A) (wherein, the diimide diester compound (B) shown in formula (1) is not included). Among them, the tetracarboxylic acid dianhydride or its derivative shown in formula (2) is preferred. The amount of the tetracarboxylic acid dianhydride or its derivative shown in formula (2) used is preferably 10 mol% or more, more preferably 20 mol% or more, relative to 1 mole of the total tetracarboxylic acid derivative component reacting with the diamine component.

[0140] <Method for manufacturing polyimide precursors>

[0141] Polyamic acid, as one of the precursors of polyimide, can be manufactured by the following method. Specifically, it is synthesized by reacting a tetracarboxylic acid derivative component containing tetracarboxylic acid dianhydride with the above-mentioned diamine component in the presence of an organic solvent at -20 to 150°C, preferably at 0 to 50°C, for 30 minutes to 24 hours, preferably for 1 to 12 hours (condensation reaction).

[0142] Specific examples of organic solvents used in the above reactions include: N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and 1,3-dimethyl-2-imidazolinone. Furthermore, where 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 can also be mixed.

[0143] The reaction can be carried out at any concentration, preferably 1-50% by mass, more preferably 5-30% by mass. Alternatively, the reaction can be carried out at a high concentration initially, followed by the addition of solvent. In the reaction, the ratio of the total molar number of the diamine component to the total molar number of the tetracarboxylic acid derivative component is preferably 0.8-1.2. Similar to conventional polycondensation reactions, the closer this molar ratio is to 1.0, the larger the molecular weight of the resulting polyamic acid.

[0144] The polyamic acid obtained in the above reaction can be recovered by precipitating it out and injecting the reaction solution into a poor solvent while stirring thoroughly. Alternatively, after several precipitation processes, washing with the poor solvent, and drying at room temperature or by heating, purified polyamic acid powder can be obtained. Poor solvents are not particularly limited, but examples include: water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.

[0145] Polyamic acid esters, as one of the precursors of polyimide, can be manufactured by the following known methods: (1) esterification of the above-mentioned polyamic acid; (2) reaction of a tetracarboxylic acid derivative component containing a tetracarboxylic acid diester dichloride with a diamine component; (3) polycondensation of a tetracarboxylic acid derivative component containing a tetracarboxylic acid diester with a diamine, etc.

[0146] The aforementioned polyamic acid and polyamic ester can also be end-modified polymers obtained by using a suitable end-capping agent together with the tetracarboxylic acid derivative component and diamine component as described above during their manufacture.

[0147] Examples of capping agents include: acetic anhydride, maleic anhydride, nadic anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, 3-(3-trimethoxysilyl)propyl-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, 4-ethynyl phthalic anhydride, etc.; dicarbonate diesters such as ditert-butyl dicarbonate and diallyl dicarbonate; chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride, and nicotinyl chloride; aniline, etc. Monoamine compounds such as 2-aminophenol, 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, and n-octylamine; monoisocyanate compounds 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.

[0148] The proportion of the capping agent used relative to the total 100 moles of the diamine component used is preferably 40 moles or less, and more preferably 30 moles or less.

[0149] <Manufacturing Method of Polyimide>

[0150] The polyimide used in this invention is manufactured by imidizing the above-mentioned polyimide precursor using a known method.

[0151] In polyimides, the ring-closing rate (also known as the imidization rate) of the functional groups in polyamic acid or polyamic ester does not necessarily have to be 100% and can be adjusted arbitrarily according to the application and purpose.

[0152] Methods for obtaining polyimide by imidizing the above-mentioned polyamic acid or polyamic acid ester include: thermal imidization by heating while maintaining the solution of the above-mentioned polyamic acid or polyamic acid ester in this state, or catalytic imidization by adding a catalyst (e.g., a basic catalyst such as pyridine, an acid anhydride such as acetic anhydride) to the solution of the above-mentioned polyamic acid or polyamic acid ester.

[0153] <Polymer solution viscosity / molecular weight>

[0154] Regarding the polyamic acid, polyamic acid ester, and polyimide used in this invention, from an operational point of view, when preparing a solution with a concentration of 10-15% by mass, a solution viscosity of 10-1000 mPa·s is preferred, for example, but not particularly limited. It should be noted that the solution viscosity (mPa·s) of the aforementioned polymers is a value measured at 25°C using an E-type rotational viscometer for a polymer solution with a concentration of 10-15% by mass prepared using a good solvent for the polymer (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0155] The weight-average molecular weight (Mw) of the polyamic acid, polyamic acid ester, and polyimide, as determined by gel permeation chromatography (GPC) of polystyrene, is preferably 1,000 to 500,000, more preferably 2,000 to 500,000. Furthermore, the molecular weight distribution (Mw / Mn) shown by the ratio of Mw to the number-average molecular weight (Mn) of polystyrene determined by GPC is preferably 15 or less, more preferably 10 or less. Within this molecular weight range, good liquid crystal alignment of the liquid crystal display element can be ensured.

[0156] <Liquid Crystal Alignment Agent>

[0157] The liquid crystal alignment agent of the present invention is used to manufacture liquid crystal alignment films, and from the viewpoint of forming a uniform thin film, it is adopted in the form of a coating liquid. In the liquid crystal alignment agent of the present invention, a coating liquid containing the aforementioned polymer component and solvent is preferred.

[0158] The content (concentration) of the polymer component contained in the liquid crystal alignment agent of the present invention can also be appropriately changed according to the desired thickness of the coating film. From the perspective of forming a uniform and defect-free coating film, it is preferably 1% by mass or more, and from the perspective of the storage stability of the solution, it is preferably 10% by mass or less.

[0159] The solvent used in liquid crystal alignment agents is not particularly limited as long as it uniformly dissolves the polymer components. Specific examples include: N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactic acid, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-... Dimethylpropionamide, N-n-propyl-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-n-butyl-2-pyrrolidone, N-tert-butyl-2-pyrrolidone, N-n-pentyl-2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone (also collectively referred to as "good solvents"), etc. Among these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, or γ-butyrolactone are preferred. The content of the good solvent is preferably 20-99% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 20-90% by mass, and particularly preferably 30-80% by mass.

[0160] Furthermore, the solvent contained in the liquid crystal alignment agent is preferably a mixed solvent that, in addition to the solvents mentioned above, also uses a solvent that improves the coatability and surface smoothness of the coating film when applying the liquid crystal alignment agent (also known as a poor solvent). Specific examples of the poor solvents used are described below, but are not limited thereto.

[0161] Examples include: diisopropyl ether, diisobutyl ether, diisobutylmethanol (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-ethoxyacetic acid butyl ester, 1-methylacetic acid pentyl ester, 2-ethylacetic acid butyl ester, 2-ethylacetic acid hexyl ester, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol, 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, diisobutyl ketone (2,6-dimethyl-4-heptanone), etc. The content of the undesirable 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 undesirable solvent are appropriately selected according to the coating apparatus, coating conditions, coating environment, etc. of the liquid crystal alignment agent.

[0162] Among them, diisobutyl methanol, 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.

[0163] Preferred combinations of good and bad solvents include: N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and diethylene glycol monobutyl ether. Diethyl ether; N-methyl-2-pyrrolidone, γ-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 diisobutylmethanol; N-methyl-2-pyrrolidone, γ-butyrolactone and dipropylene glycol dimethyl ether; N-methyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol dimethyl ether, etc.

[0164] The liquid crystal alignment agent of the present invention may also contain additional components (hereinafter also referred to as additive components) other than polymer components and solvents. Examples of such additive components include: compounds for improving the strength of the liquid crystal alignment film (hereinafter also referred to as crosslinking compounds); adhesion promoters 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; dielectrics, conductive materials, etc., for adjusting the dielectric constant and resistance of the liquid crystal alignment film.

[0165] Examples of such crosslinking compounds include at least one crosslinking compound selected from the group consisting of crosslinking compounds having substituents (c-1) and crosslinking compounds having polymerizable unsaturated groups (c-2), wherein the substituents are selected from at least one of epoxy groups, oxacyclobutane groups, oxazoline structures, cyclic carbonate groups, terminal isocyanate groups, hydroxyl groups, and alkoxy groups.

[0166] Specific examples of preferred crosslinking compounds (c-1) and (c-2) mentioned above include the following compounds.As compounds with epoxy groups, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, 2,2-dibromonepentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, bisphenol A type epoxy resins such as EPIKOTE 828 (manufactured by MITSUBISHI CHEMICAL), bisphenol F type epoxy resins such as EPIKOTE 807 (manufactured by MITSUBISHI CHEMICAL), and YX-8000 (manufactured by MITSUBISHI...) are examples of such epoxy resins. Hydrogenated bisphenol A type epoxy resin (manufactured by CHEMICAL), YX6954BH30 (manufactured by MITSUBISHI CHEMICAL) and other epoxy resins containing a biphenyl backbone, EPPN-201 (manufactured by Nippon Kayaku Co.) and other phenolic varnish type epoxy resins, EOCN-102S (manufactured by Nippon Kayaku Co.) and other (o-, m-, p-)cresol phenolic varnish type epoxy resins, tetra(glycidyloxymethyl)methane, N,N,N',N'-tetraglycidyl-1,4-phenylenediamine, N, Compounds in which tertiary nitrogen atoms are bonded to aromatic carbon atoms, such as N,N',N'-tetraglycidyl-2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2-bis[4-(N,N-diglycidyl-4-aminophenoxy)phenyl]propane, and N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane; N,N,N',N'-tetraglycidyl-1,2-diaminocyclohexane, N,N,N',N'-tetraglycidyl-1,3-diaminocyclohexane, and N,N,N' N'-Tetraglycidyl-1,4-diaminocyclohexane, bis(N,N-diglycidyl-4-aminocyclohexyl)methane, bis(N,N-diglycidyl-2-methyl-4-aminocyclohexyl)methane, bis(N,N-diglycidyl-3-methyl-4-aminocyclohexyl)methane, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,4-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,3-bis(N,N-diglycidylaminomethyl)benzene, 1,4 - Compounds in which tertiary nitrogen atoms are bonded to aliphatic carbon atoms, such as 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 TEPIC (manufactured by Nissan Chemical Co., Ltd.); compounds described in paragraph 0037 of Japanese Patent Application Publication No. 10-338880; and compounds described in WO2017 / 170483, etc.

[0167] Compounds having oxetyl groups include 1,4-bis{[(3-ethyl-3-oxetyl)methoxy]methyl}benzene (ARON OXETANE OXT-121(XDO)), di[2-(3-oxetyl)butyl] ether (ARON OXETANE OXT-221(DOX)), 1,4-bis[(3-ethyloxetane-3-yl)methoxy]benzene (HQOX), 1,3-bis[(3-ethyloxetane-3-yl)methoxy]benzene (RSOX), 1,2-bis[(3-ethyloxetane-3-yl)methoxy]benzene (CTOX), and compounds having two or more oxetyl groups as described in paragraphs 0170 to 0175 of WO2011 / 132751.

[0168] Compounds having an oxazoline structure include 2,2'-bis(2-oxazoline), 2,2'-bis(4-methyl-2-oxazoline), etc.; polymers and oligomers with an oxazoline group, such as EPOCROS (trade name, Nippon Shokubai Co., Ltd.); and compounds described in paragraph 0115 of Japanese Patent Application Publication No. 2007-286597.

[0169] Compounds having a cyclic carbonate group include N,N,N',N'-tetratetra[(2-oxo-1,3-dioxolane-4-yl)methyl]-4,4'-diaminodiphenylmethane, N,N',-di[(2-oxo-1,3-dioxolane-4-yl)methyl]-1,3-phenylenediamine, and compounds described in paragraphs 0025 to 0030 and 0032 of WO2011 / 155577.

[0170] Compounds having end-capped isocyanate groups include: CORONATE AP stable M, CORONATE 2503, 2515, 2507, 2513, 2555, MILLIONATE MS-50 (all manufactured by TOSOH); TAKENATE B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, B-882N (all manufactured by Mitsui Chemicals); compounds having two or more protected isocyanate groups as described in paragraphs 0046 to 0047 of Japanese Patent Application Publication No. 2014-224978; and compounds having three or more protected isocyanate groups as described in paragraphs 0119 to 0120 of WO2015 / 141598.

[0171] Compounds having hydroxyl and / or alkoxy groups include N,N,N',N'-tetra(2-hydroxyethyl)hexamethylenediamine, 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 paragraph 0058 of Japanese Patent Application Publication No. 2015 / 072554 and No. 2016-118753, compounds described in Japanese Patent Application Publication No. 2016-200798, and compounds described in WO2010 / 074269.

[0172] As cross-linked compounds with polymerizable unsaturated groups, these include mono(meth)acrylates, di(meth)acrylates (a mixture of 1,2- and 1,3-type compounds), tri(meth)acrylates, glycerol 1,3-diglyceryl alcohol di(meth)acrylate, pentaerythritol tri(meth)acrylate, diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, pentaethylene glycol mono(meth)acrylate, and hexaethylene glycol mono(meth)acrylate.

[0173] The above-described compound is an example of a cross-linking compound, but is not limited thereto. Examples include, for instance, components other than those described above, disclosed on page 53, paragraph 0105 to page 55, paragraph 0116 of WO2015 / 060357. Furthermore, two or more cross-linking compounds may be combined.

[0174] When using a crosslinking compound, the content of the crosslinking compound in the liquid crystal alignment agent is preferably 0.5 to 20 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent, more preferably 1 to 15 parts by mass.

[0175] Examples of such sealing agents include: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureopropyltrimethoxysilane, 3-ureopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxy 3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 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 Silane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis(oxoethylidene)-3-aminopropyltrimethoxysilane, N-bis(oxoethylidene)-3-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-epoxypropoxypropyl Silane coupling agents such as oxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanopropyltriethoxysilane.

[0176] When using an adhesive additive, the content of the adhesive additive in the liquid crystal alignment agent is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent, more preferably 0.1 to 20 parts by mass.

[0177] (Liquid crystal alignment film)

[0178] The liquid crystal alignment film of the present invention is formed using the liquid crystal alignment agent of the present invention described above.

[0179] The manufacturing method of the liquid crystal alignment film of the present invention includes, for example, coating the above-mentioned liquid crystal alignment agent onto a substrate, firing it to obtain a film, and irradiating the film with radiation.

[0180] As a preferred embodiment of the manufacturing method of the liquid crystal alignment film of the present invention, a manufacturing method of the liquid crystal alignment film including the following steps can be listed, for example: a step of coating the above-mentioned liquid crystal alignment agent onto a substrate (step (1)); a step of firing the coated liquid crystal alignment agent (step (2)); and a step of aligning the film obtained in step (2) as appropriate (step (3)).

[0181] <Process (1)>

[0182] As for the substrate used in this invention for coating the liquid crystal alignment agent, there are no particular limitations as long as it is a highly transparent substrate; glass substrates, silicon nitride substrates, acrylic substrates, polycarbonate substrates, and other plastic substrates can also be used. In this case, using a substrate with ITO (Indium Tin Oxide) electrodes for driving the liquid crystal is preferable from the perspective of process simplification. Furthermore, in reflective liquid crystal display elements, if the substrate is only on one side, an opaque object such as a silicon wafer can be used, and the electrodes can be made of light-reflecting materials such as aluminum.

[0183] Methods for coating a liquid crystal alignment agent onto a substrate to form a film include screen printing, offset printing, flexographic printing, inkjet printing, and spraying. Among these, inkjet printing is preferred.

[0184] <Process (2)>

[0185] Step (2) is a step of firing the liquid crystal alignment agent coated on the substrate to form a film. After the liquid crystal alignment agent is coated on the substrate, the solvent can be evaporated using a heating unit such as a heating plate, a thermally circulating oven, or an IR (infrared) oven; or thermal imidization of the amyl acid or amyl ester in the polymer can be performed. 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 can be performed multiple times. As for the temperature at which the solvent of the liquid crystal alignment agent is evaporated, it can be performed, for example, at 40 to 180°C. From the viewpoint of shortening the process, it can be performed at 40 to 150°C. As for the firing time, there is no particular limitation, and examples include 1 to 10 minutes or 1 to 5 minutes. In the case of thermal imidization of the amyl acid or amyl ester in the polymer, the firing step can also be performed after the above-mentioned solvent evaporation step, for example, at a temperature range of 150 to 300°C or 150 to 250°C. As for the firing time, there is no particular limitation, and examples include 5 to 40 minutes or 5 to 30 minutes.

[0186] If the film after firing is too thin, the reliability of the liquid crystal display element may be reduced. Therefore, 5 to 300 nm is preferred, and 10 to 200 nm is more preferred.

[0187] <Process (3)>

[0188] Step (3) is a step of aligning the film obtained in step (2) as needed. That is, in vertically aligned liquid crystal display elements such as VA mode or PSA (Polymer-Sustained Alignment) mode, the formed coating can be kept in this state and used as a liquid crystal alignment film, or the coating can be aligned. The alignment treatment mentioned here refers to the treatment that has anisotropy in the horizontal direction. As an alignment treatment method for liquid crystal alignment film, a friction treatment method can be used, but a photo-alignment treatment method is preferred. As a photo-alignment treatment method, the following methods can be listed: irradiating the surface of the above-mentioned film with radiation in a way that imparts an orientation in a certain direction, and, depending on the situation, preferably performing a heating treatment at a temperature of 150 to 250°C to impart liquid crystal alignment properties (also known as liquid crystal alignment capability). There is no particular limitation on the type of radiation, and ultraviolet light, visible light, electron beams, etc. can be used. When using ultraviolet light or visible light, it is preferred to use light that is polarized by using a polarizer (also known as a polarizing plate) (hereinafter referred to as polarized light). Among the wavelengths of ultraviolet and visible light, it is important to use the wavelengths that react to the photosensitive sites in the polymer. Therefore, there are no particular limitations, but ultraviolet and visible light in the range of 100 nm to 500 nm are preferred, and polarized ultraviolet light in the range of 200 to 400 nm is particularly preferred.

[0189] The preferred radiation dose is 1–10,000 mJ / cm². 2 The preferred value is 100–5000 mJ / cm³. 2 Furthermore, to improve liquid crystal alignment, heating can be performed simultaneously with irradiation when exposed to radiation. The heating temperature is not particularly limited, but is preferably 50–250°C. The liquid crystal alignment film produced in this way allows the liquid crystal molecules to be stably aligned in a specific direction.

[0190] Furthermore, a solvent can be used to contact the liquid crystal alignment film obtained by the above method, and a heat treatment can be performed after the contact treatment.

[0191] The solvent used in the above-described contact treatment is not particularly limited as long as it can dissolve the decomposition products generated by radiation irradiation. 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 from the perspective of versatility and solvent safety. Water, 1-methoxy-2-propanol, or ethyl lactate are more preferred. One solvent may be used, or a combination of two or more may be used.

[0192] Examples of the contact treatments described above include immersion treatment and spray treatment (also known as coating treatment). From the perspective of efficiently dissolving the decomposition products generated by radiation irradiation, the treatment time in these treatments is preferably 10 seconds to 1 hour. Immersion treatment for 1 to 30 minutes is preferred. Furthermore, the contact treatments described above can be performed by cooling or heating, and the preferred temperature of the solvent used in the contact treatment is 10 to 80°C. Preferably, it is 20 to 50°C. In addition, from the perspective of the solubility of the decomposition products, ultrasonic treatment or the like can be performed as needed.

[0193] Following the above contact treatment, rinsing (also called washing) and firing are preferably performed using low-boiling-point solvents such as water, methanol, ethanol, 2-propanol, acetone, and methyl ethyl ketone. At this time, either rinsing or firing, or both, can be performed. The firing temperature is preferably 150–300°C, more preferably 180–250°C, and more preferably 200–230°C. Furthermore, the firing time is preferably 10 seconds to 30 minutes, preferably 1 to 10 minutes.

[0194] The heat treatment of the above-mentioned radiation-irradiated coating is more preferably performed at 50 to 300°C for 1 to 30 minutes, and even more preferably at 120 to 250°C for 1 to 30 minutes.

[0195] (Liquid crystal display element)

[0196] The liquid crystal display element of the present invention has the liquid crystal alignment film of the present invention.

[0197] From the viewpoint of obtaining good horizontal uniaxial alignment, the liquid crystal alignment film of the present invention is preferred as a liquid crystal alignment film for liquid crystal display elements of lateral electric field type such as IPS and FFS, and in particular, it is useful as a liquid crystal alignment film for liquid crystal display elements of FFS type.

[0198] Liquid crystal display elements can be manufactured as follows: after obtaining a substrate with a liquid crystal alignment film obtained by the liquid crystal alignment agent of the present invention, a liquid crystal cell is fabricated by a known method, and liquid crystal is sealed into the liquid crystal cell. Specifically, the following two methods can be listed.

[0199] In the first method, two substrates are first arranged opposite each other with a gap (cell gap) set so that their respective liquid crystal alignment films are facing each other. Next, the peripheries of the two substrates are bonded together using a sealant, and a liquid crystal composition is injected into the cell defined by the substrate surface and the sealant. After contact with the film surface, the injection hole is sealed.

[0200] The second method is known as the ODF (One Drop Fill) method. A UV-curable sealant is applied to either of two substrates on which a liquid crystal alignment film has been formed, creating an area for sealing the liquid crystal. An amount of liquid crystal composition, equivalent to the cell volume, is then dropped onto the liquid crystal alignment film surface within this area at regular intervals. Next, the other substrate is bonded under vacuum with the liquid crystal alignment films facing each other, spreading the liquid crystal composition across the entire substrate surface to contact the film surface. Then, UV light is irradiated through a photomask without exposing the entire substrate surface or the liquid crystal alignment film to light, resulting in temporary curing. The sealant is further cured by heat treatment, thereby obtaining a liquid crystal display element.

[0201] Regardless of whether the first or second method is used, it is ideal to further heat the liquid crystal composition to a temperature at which it becomes an isotropic phase, and then slowly cool it to room temperature, thereby removing the flow orientation during liquid crystal filling.

[0202] It should be noted that when the coating has undergone a friction treatment, the two substrates are arranged opposite each other at a predetermined angle, such as orthogonal or antiparallel, with the friction directions of each coating being opposite each other. Similarly, when a photo-alignment treatment has been performed, the substrates are arranged opposite each other with their alignment directions at a predetermined angle, such as orthogonal or antiparallel.

[0203] As a sealant, epoxy resin containing a curing agent and alumina spheres as spacers can be used, for example. Nematic liquid crystals and smectic liquid crystals can be cited as examples, with nematic liquid crystals being preferred.

[0204] Specific examples of compounds constituting the above-mentioned nematic liquid crystals include: Schiff base liquid crystal compounds, azo-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, etc.

[0205] The liquid crystal composition can be any type of positive liquid crystal composition or negative liquid crystal composition, but a negative liquid crystal composition is preferred from the perspective of maximizing transmittance during driving.

[0206] Representative commercially available positive liquid crystal compositions include ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019 or MLC-7081 manufactured by MERCK, or PA-1492 manufactured by DIC.

[0207] 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 manufactured by MERCK.

[0208] Next, the polarizing plates are set. Specifically, a pair of polarizing plates are attached to the surfaces of the two substrates opposite to the liquid crystal layer. Examples of polarizing plates include: a polarizing plate made by sandwiching a polarizing film called an "H film" between a cellulose acetate protective film; or a polarizing plate made of the H film itself, wherein the H film is formed by absorbing iodine while extending and oriented polyvinyl alcohol.

[0209] Example

[0210] The following examples illustrate the invention in further detail, but the invention is not limited thereto. The abbreviations of the compounds and the methods for determining their properties are described below.

[0211] (Diamine)

[0212]

[0213] (Tetracarboxylic acid dianhydride)

[0214]

[0215] (Diimide diester compound)

[0216]

[0217] (additive)

[0218]

[0219] (solvent)

[0220] NMP: N-methyl-2-pyrrolidone.

[0221] BCS: Ethylene glycol monobutyl ether.

[0222] <Viscosity Measurement>

[0223] The viscosity of the solution was measured using a TVE-22H type E viscometer (manufactured by Toki Sangyo Co., Ltd.), with a sample volume of 1.1 mL, using a conical rotor TE-1 (1°34', R24), at a temperature of 25°C.

[0224] <Determination of molecular weight>

[0225] The molecular weight of the polymer was determined using a room-temperature gel permeation chromatography (GPC) apparatus (GPC-101) (manufactured by Showa Denko Corporation) and chromatographic columns (KD-803 and KD-805 in series) (manufactured by Showa Denko Corporation), as described below.

[0226] Column temperature: 50℃.

[0227] Eluent: N,N-dimethylformamide (as additives, lithium bromide monohydrate (LiBr·H2O) 30 mmol / L, anhydrous phosphate (o-phosphate) 30 mmol / L, tetrahydrofuran (THF) 10 mL / L).

[0228] Flow rate: 1.0 ml / min.

[0229] Standard samples used for calibration curve preparation: TSK standard polyethylene oxide (molecular weight; approximately 900,000, 150,000, 100,000 and 30,000) (manufactured by TOSOH) and polyethylene glycol (molecular weight; approximately 12,000, 4,000 and 1,000) (manufactured by Polymer Laboratories).

[0230] <Synthesis of Monomers>

[0231] DI-1 to DI-4 are novel compounds not disclosed in the literature. The synthesis method is described in detail below.

[0232] The products described in Examples 1-4 of the following monomer synthesis were obtained by... 1 Identification was performed using H-NMR analysis (analytical conditions are described below).

[0233] Apparatus: Varian NMR System 400NB (400MHz).

[0234] Solvent used for determination: DMSO-d6.

[0235] Reference material: Tetramethylsilane (TMS) 1 H is δ 0.0 ppm).

[0236] (Synthesis of Monomer Example 1: Synthesis of DI-1)

[0237]

[0238] <Synthesis of DI-1-1>

[0239] Acetic acid (AcOH, 489 g), CA-1 (61.1 g, 312 mmol), and ammonium acetate (AcNH4, 24.0 g, 312 mmol) were added to a 2 L four-necked flask and reacted under reflux in a nitrogen atmosphere for about 2 days. After the reaction was completed, pure water (1500 g) was added to the reaction solution and stirred. The precipitate was filtered off, washed with pure water and methanol, and dried to obtain DI-1-1 (yield: 51.9 g, 267 mmol, yield: 86%, appearance: white crystals).

[0240] <Synthesis of DI-1>

[0241] 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 added to a 1 L four-necked flask. Ethyl chloroformate (32.0 g, 295 mmol) was added dropwise under a nitrogen atmosphere and ice-cold conditions. After the addition, the reaction was allowed to proceed at room temperature (25 °C) for 15 hours until the starting material disappeared (slurry solution). The slurry solution was filtered, and the filter was washed with excess dichloromethane and dried to obtain DI-1 (yield: 11.0 g, 32.5 mmol, yield: 24%, appearance: white-peach crystals).

[0242] 1 H-NMR (400MHz, DMSO-d6): δ (ppm) = 4.37 (q, 4H, J = 7.2Hz), 3.52 (s, 4H), 1.30 (t, 6H, J = 7.2Hz).

[0243] (Synthesis of Monomer Example 2: Synthesis of DI-2)

[0244]

[0245] <Synthesis of DI-2>

[0246] N,N-dimethylacetamide (250 g), DI-1-1 (25.0 g, 129 mmol), and 4-dimethylaminopyridine (1.58 g, 12.9 mmol) were added dropwise to a 2 L four-necked flask under a nitrogen atmosphere at room temperature (25 °C). Di-tert-butyl dicarbonate (Boc₂O, 61.9 g, 284 mmol) was added dropwise. After the addition, the reaction was allowed to proceed at room temperature for 14 hours to allow the starting material to dissipate. After the reaction was complete, 2-propanol (750 g) was added to the reaction mixture and stirred. The precipitate was filtered off and washed with 2-propanol to obtain DI-2 (yield: 48.1 g, 122 mmol, yield: 95%, appearance: white crystals).

[0247] 1 H-NMR (400MHz, DMSO-d6): δ (ppm) = 3.50 (s, 4H), 1.52 (s, 18H).

[0248] (Synthesis of Monomer Example 3: Synthesis of DI-3)

[0249]

[0250] <Synthesis of DI-3>

[0251] The above scheme was carried out by the same operation as described in Monomer Synthesis Example 1 and Monomer Synthesis Example 2, thereby obtaining DI-3 (yield: 20.6 g, 48.7 mmol, yield: 83%, appearance: white crystals).

[0252] 1 H-NMR (400MHz, DMSO-d6): δ (ppm) = 3.30-3.01 (m, 4H), 2.05-2.03 (m, 4H), 1.50-1.49 (m, 18H).

[0253] (Synthesis of Monomer Example 3: Synthesis of DI-4)

[0254]

[0255] <Synthesis of DI-4-1>

[0256] Acetic acid (245 g), CA-4 (14.0 g, 46.3 mmol), and ammonium acetate (21.5 g, 278 mmol) were added to a 300 mL four-necked flask and reacted under reflux at a nitrogen atmosphere for approximately 20 hours. After the reaction was complete, pure water (150 g) was added to the reaction solution and stirred. The precipitate was filtered off, washed with pure water and methanol, and dried to obtain DI-4-1 (yield: 6.98 g, 23.2 mmol, yield: 50%, appearance: white crystals).

[0257] <Synthesis of DI-4>

[0258] Tetrahydrofuran (125 g), DI-4-1 (6.0 g, 20 mmol), and 4-dimethylaminopyridine (0.024 g, 0.2 mmol) were added to a 200 mL four-necked flask. 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 complete, hexane (150 g) was added to the reaction solution and stirred. The precipitate was filtered off and washed with ethyl acetate (85 g) to obtain DI-4 (yield: 4.37 g, 8.73 mmol, 44% yield, appearance: white crystals).

[0259] 1 H-NMR (400MHz, 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, 1 H, J=13.0Hz), 1.48 (d, 18H, J=3.2Hz), 1.30 (d, 1H, J=11.0Hz), 1.10 (d, 1H, J=11.0Hz), 0.79 (d, 1H, J=12.8Hz).

[0260] <Polymer Synthesis>

[0261] (Synthesis example 1)

[0262] 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 to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and stirred at room temperature until dissolved. Then, CA-1 (2.34 g, 10.4 mmol) was added, followed by NMP at a solids concentration of 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 polyamic acid had a number-average molecular weight of 11244 and a weight-average molecular weight of 30370.

[0263] (Synthesis example 2)

[0264] 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 to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and stirred at room temperature until dissolved. Then, CA-1 (1.85 g, 8.25 mmol) and CA-2 (0.431 g, 2.20 mmol) were added, followed by NMP at a solids concentration of 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 polyamic acid had a number-average molecular weight of 12175 and a weight-average molecular weight of 30201.

[0265] (Synthesis example 3)

[0266] 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 to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and stirred at room temperature until dissolved. Then, DI-1 (0.677 g, 2.00 mmol) was added, and the mixture was stirred at 60 °C for 5 hours until dissolved. The mixture was then cooled to 40 °C, and CA-1 (1.78 g, 7.95 mmol) was added, followed by NMP at a solids concentration of 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 10861, and the weight-average molecular weight was 26472.

[0267] The polymer obtained above was subjected to 1 H-NMR measurements showed that a peak originating from ethyl carbamate, which was not observed in the polymers of Synthetic Example 1 and Synthetic Example 2, was confirmed near 1.29 ppm, and a new amide peak was confirmed in the range of 11.00 to 8.00 ppm. It can be considered that the group represented by formula (1A) originating from DI-1 was successfully introduced.

[0268] (Synthesis Example 4)

[0269] 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 to a 50 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and stirred at room temperature until dissolved. Then, DI-2 (0.789 g, 2.00 mmol) was added, and the mixture was stirred at 60 °C for 5 hours until dissolved. The mixture was then cooled to 40 °C, and CA-1 (1.78 g, 7.95 mmol) was added, followed by NMP at a solids concentration of 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 10531, and the weight-average molecular weight was 26987.

[0270] The polymer obtained above 1 H-NMR measurements showed that a peak derived from the tert-butyl group, which is different from the tert-butyl urethane group of DA-4 used in the polymers of Synthetic Examples 1 and 2, was identified at around 1.33 ppm, and a new amide peak was identified at 11.00 to 8.00 ppm. Therefore, it can be considered that the group represented by formula (1A) derived from DI-2 was successfully introduced.

[0271] (Synthesis Example 5)

[0272] DA-5 (6.38 g, 32.0 mmol), DA-6 (1.22 g, 8.00 mmol), and NMP (109 g) were added to a 200 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and stirred at room temperature until dissolved. Then, CA-3 (11.3 g, 38.3 mmol) was added, followed by NMP at a solids concentration of 12% by mass. The mixture was stirred at room temperature for 24 hours to obtain a polyamic acid solution (PAA-B1) (viscosity: 384 mPa·s).

[0273] <Synthesis Example 6>

[0274] 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 to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and stirred at room temperature until dissolved. Then, DI-3 (0.634 g, 1.50 mmol) was added, and the mixture was stirred at 60 °C for 5 hours until dissolved. The mixture was then cooled to 40 °C, and CA-1 (1.79 g, 8.00 mmol) was added, followed by NMP at a solids concentration of 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 6432, and the weight-average molecular weight was 13826.

[0275] The polymer obtained above 1 H-NMR measurements showed that a peak derived from the tert-butyl group, which is different from the tert-butyl urethane group of DA-4 used in the polymers of Synthetic Examples 1 and 2, was identified at around 1.47 ppm, and a new amide peak was identified at 11.00 to 8.00 ppm. Therefore, it can be considered that the group represented by formula (1A) derived from DI-3 was successfully introduced.

[0276] <Synthesis Example 7>

[0277] 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 to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, and stirred at room temperature until dissolved. Then, DI-4 (0.751 g, 1.50 mmol) was added, and the mixture was stirred at 60 °C for 5 hours until dissolved. The mixture was then cooled to 40 °C, and CA-1 (1.79 g, 8.00 mmol) was added, followed by NMP at a solids concentration of 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 4504, and the weight-average molecular weight was 9731.

[0278] The polymer obtained above 1H-NMR measurements showed that a peak derived from the tert-butyl group, which is different from the tert-butyl urethane group of DA-4 used in the polymers of Synthetic Examples 1 and 2, was identified around 1.40 ppm, and a new amide peak was identified in the range of 11.00 to 8.00 ppm. Therefore, it can be considered that the group represented by formula (1A) derived from DI-4 was successfully introduced.

[0279] [Table 1]

[0280]

[0281] <Preparation of Liquid Crystal Alignment Agent>

[0282] (Example 1)

[0283] NMP (5.67 g) and BCS (6.00 g) were added to the polymer solution PAA-A1 (8.33 g) obtained in Synthesis Example 3, and the mixture was stirred at room temperature for 2 hours to obtain liquid crystal alignment agent (V-1).

[0284] (Example 2)

[0285] The polymer solution used was changed from PAA-A1 to PAA-A2, but otherwise the operation was the same as in Example 1, thereby obtaining the liquid crystal alignment agent (V-2).

[0286] (Example 3)

[0287] NMP (14.00 g) and BCS (6.00 g) were added to the polymer solution PAA-A3 (10.00 g) obtained in Synthesis Example 6, and the mixture was stirred at room temperature for 2 hours to obtain liquid crystal alignment agent (V-3).

[0288] (Example 4)

[0289] NMP (14.00 g) and BCS (6.00 g) were added to the polymer solution PAA-A4 (10.00 g) obtained in Synthesis Example 7, and the mixture was stirred at room temperature for 2 hours to obtain liquid crystal alignment agent (V-4).

[0290] (Example 5)

[0291] Add the polyamic acid solution PAA-B1 (4.39 g), NMP (3.80 g), BCS (4.80 g), a 10% mass dilution of NMP1 in AD-1 (0.376 g), and a 1% mass dilution of NMP1 in AD-2 (0.752 g) obtained in Synthesis Example 5 to the polymer solution PAA-A2 (1.88 g) obtained in Synthesis Example 4. Stir at room temperature for 2 hours to obtain liquid crystal alignment agent (V-5).

[0292] (Comparative Example 1) to (Comparative Example 2)

[0293] The polymer used was changed from PAA-A1 to polyamic acid solutions PAA-R1 to PAA-R2, and the operation was otherwise the same as in Example 5, thereby obtaining liquid crystal alignment agents (RV-1) to (RV-2).

[0294] The specifications of the liquid crystal alignment agents obtained in Examples 1-5 and Comparative Examples 1-2 are shown in Table 2. The values ​​in parentheses for polymer components indicate the proportion (parts by mass) of each polymer component relative to 100 parts by mass of the total polymer components.

[0295] [Table 2]

[0296]

[0297] Using the liquid crystal alignment agent obtained above, an FFS-driven liquid crystal cell was fabricated in the order shown below, and various evaluations were performed.

[0298] <Composition of FFS-driven liquid crystal cells>

[0299] A liquid crystal cell with an FFS mode liquid crystal display element was manufactured.

[0300] First, a substrate with electrodes was prepared. The substrate was a rectangular glass substrate measuring 30mm × 35mm with a thickness of 0.7mm. On the substrate, a first layer was formed of ITO electrodes with a dense pattern constituting a common electrode. On the common electrode of the first layer, a second layer was formed of a SiN (silicon nitride) film deposited by CVD (chemical vapor deposition). The SiN film of the second layer had a thickness of 300nm and functioned as an interlayer insulating film. On the SiN film of the second layer, a third layer was formed of comb-shaped pixel electrodes formed by patterning the ITO film, forming two types of pixels: a first pixel and a second pixel. Each pixel had dimensions of 10mm in length and 5mm in width. This substrate with electrodes had a structure insulated between the common electrode of the first layer and the pixel electrode of the third layer by the SiN film of the second layer.

[0301] The third layer of pixel electrodes has a comb-like shape formed by multiple electrode lines with a width of 3μm and an inner angle of 160° arranged in parallel. Each pixel is formed by multiple electrode lines and has a first region and a second region with the line connecting the curved parts as the boundary.

[0302] 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 using a filter with a pore size of 1.0 μm. These agents were then spin-coated onto the aforementioned electrode substrate (hereinafter referred to as the electrode substrate) and a glass substrate with an ITO film on its back side and columnar spacers with a height of 4 μm (hereinafter referred to as the opposing substrate). After drying on a heating plate at 80°C for 2 minutes, the substrate was fired in a hot air circulating oven at 230°C for 20 minutes to form a coating film with a thickness of 100 nm. The coating surface was irradiated with polarized ultraviolet light filtered through a 254 nm bandpass filter and polarizer to perform alignment treatment, resulting in a substrate with a liquid crystal alignment film. The irradiation amounts are shown in Table 3 below. It should be noted that, regarding the liquid crystal alignment film formed on the aforementioned electrode substrate, the alignment process was performed such that the direction in which the inner angles of the pixel bends are equally divided is orthogonal to the alignment direction of the liquid crystal. Regarding the liquid crystal alignment film formed on the opposing substrate, the alignment process was performed such that the alignment direction of the liquid crystal on the electrode substrate is consistent with the alignment direction of the liquid crystal on the opposing substrate during the fabrication of the liquid crystal cell. Using the two substrates as a group, a sealant (Mitsui Chemicals XN-1500T) was printed onto the substrates using a dispensing machine. Another substrate was then bonded together with the alignment directions of each liquid crystal alignment film at 0° and facing each other. The bonded substrates were then pressed together and heated in a hot air circulating oven at 150°C for 60 minutes to cure the sealant, producing an empty cell. Liquid crystal PA-1492 (DIC Corporation) was injected into the empty cell using a depressurized injection method, and the injection port was sealed, thus obtaining an FFS-driven liquid crystal cell. The obtained liquid crystal cell was then heated at 120°C for 1 hour and left to stand overnight for evaluation.

[0303] <Evaluation of in-plane uniformity of contrast>

[0304] The non-uniformity of the torsion angle of liquid crystal display elements was evaluated using AxoStep manufactured by AXOMETRICS. The liquid crystal cell fabricated above was placed on a measuring stage, and the distribution of circular retardation within the pixel plane was measured without applying voltage. Three times the standard deviation σ, or 3σ, was calculated. It can be said that the smaller the value of 3σ, the better the in-plane uniformity. As an evaluation criterion, a 3σ value of 1.10 or less was defined as "excellent," a 3σ value greater than 1.10 but less than 1.30 was defined as "good," and a 3σ value greater than 1.30 was defined as "poor."

[0305] The evaluation results of liquid crystal display elements using the liquid crystal alignment agents of the above embodiments and comparative examples are shown in Table 3.

[0306] <Evaluation of the stability of liquid crystal alignment>

[0307] This evaluation assesses image retention (also known as AC image retention) caused by the deterioration of the alignment properties of the liquid crystal alignment film during long-term AC driving.

[0308] The FFS-driven liquid crystal cell fabricated above was subjected to an AC voltage of ±4.2V at a frequency of 60Hz for 120 hours under a constant temperature environment of 60°C. Then, the pixel electrode and common electrode of the liquid crystal cell were short-circuited, and the cell was left at room temperature (23°C) for one day. For the liquid crystal cell subjected to the above treatment, the deviation in orientation direction between the liquid crystal in the first region of the pixel and the liquid crystal in the second region of the pixel, in the form of angles, was calculated. Specifically, the liquid crystal cell was placed between two polarizing plates arranged orthogonally to the polarization axes, the backlight was turned on, and the arrangement angle of the liquid crystal cell was adjusted to minimize the transmitted light intensity in the first region of the pixel. Then, the rotation angle required to minimize the transmitted light intensity in the second region of the pixel was determined. It can be said that the smaller the value of this rotation angle, the better the stability of the liquid crystal orientation.

[0309] As an evaluation criterion, cases with a rotation angle value less than 0.100° are designated as "excellent", cases with a rotation angle value greater than 0.100° and less than 0.200° are designated as "good", and cases with a rotation angle value greater than 0.200° are designated as "poor".

[0310] The evaluation results of liquid crystal display elements using the liquid crystal alignment agents of the above embodiments and comparative examples are shown in Table 3.

[0311] [Table 3]

[0312]

[0313] Based on the comparison between Examples 1 to 5 and Comparative Examples 1 to 2, the liquid crystal alignment film obtained by using a liquid crystal alignment agent containing diimide diester compounds DI-1 to DI-4 showed higher in-plane uniformity and higher stability of liquid crystal alignment compared to the liquid crystal alignment film obtained by using a liquid crystal alignment agent composed of a component without diimide diester compound (B).

[0314] Industrial availability

[0315] The liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention is preferably used in various liquid crystal display elements, including those using IPS driving and FFS driving methods. Furthermore, these display elements are not limited to liquid crystal displays intended for display purposes, but are also useful in dimming windows, optical shutters, and other applications that control light transmission and blocking.

Claims

1. A liquid crystal alignment agent comprising one or more polymers A selected from the group consisting of a polyimide precursor and an imide derivative thereof, wherein the polyimide precursor is obtained by polymerizing a tetracarboxylic acid derivative component comprising at least one compound selected from the group consisting of tetracarboxylic dianhydrides and their derivatives and a diimide diester compound B represented by formula (1) with a diamine component, wherein the at least one compound selected from the group consisting of tetracarboxylic dianhydrides and their derivatives does not include a tetracarboxylic acid diimide diester compound. The polymer A has a group derived from the diimide diester compound B, represented by the following formula (1A). In formula (1), X1 represents a tetravalent organic group derived from acyclic aliphatic tetracarboxylic dianhydride or alicyclic tetracarboxylic dianhydride or their derivatives; R each independently represents a monovalent organic group with 1 to 5 carbon atoms. In formula (1A), R represents a monovalent organic group with 1 to 5 carbon atoms; * represents a bond bonded to X1.

2. The liquid crystal alignment agent according to claim 1, wherein, In the formula (1), X1 represents a tetravalent organic group derived from a tetracarboxylic acid dianhydride or its derivative having a noncyclic aliphatic hydrocarbon group with 4 to 16 carbon atoms or an alicyclic aliphatic hydrocarbon group with 4 to 16 carbon atoms.

3. The liquid crystal alignment agent according to claim 1, wherein, In equation (1), X1 represents any one of the following equations (x-1) to (x-18). In equations (x-1) to (x-18), R 1 ~R 4 Each of these can independently represent a hydrogen atom, a halogen atom, an alkyl group with 1 to 6 carbon atoms, an alkenyl group with 2 to 6 carbon atoms, an alkynyl group with 2 to 6 carbon atoms, a monovalent organic group containing a fluorine atom with 1 to 6 carbon atoms, an alkoxy group with 1 to 6 carbon atoms, an alkoxyalkyl group with 2 to 6 carbon atoms, an alkoxycarbonyl group with 2 to 6 carbon atoms, or a phenyl group; R 5 and R 6 Each can independently represent a hydrogen atom or a methyl group. The following structures in equation (x-9) represent single or double bonds. 。 4. The liquid crystal alignment agent according to claim 1, wherein, The diimide diester compound B is at least any one of the compounds shown in formulas (b-1) to (b-9) below. 。 5. The liquid crystal alignment agent according to claim 1, wherein, The tetracarboxylic acid derivative component includes the tetracarboxylic acid dianhydride shown in formula (2) below. In equation (2), X represents the structure selected from the group consisting of the following equations (x-1) to (x-18) and (xr-1) to (xr-2). In equations (x-1)~(x-18) and (xr-1)~(xr-2), R 1 ~R 4 Each of these can independently represent a hydrogen atom, a halogen atom, an alkyl group with 1 to 6 carbon atoms, an alkenyl group with 2 to 6 carbon atoms, an alkynyl group with 2 to 6 carbon atoms, a monovalent organic group containing a fluorine atom with 1 to 6 carbon atoms, an alkoxy group with 1 to 6 carbon atoms, an alkoxyalkyl group with 2 to 6 carbon atoms, an alkoxycarbonyl group with 2 to 6 carbon atoms, or a phenyl group; R 5 and R 6 Each can independently represent a hydrogen atom or a methyl group. The following structures in equation (x-9) represent single or double bonds. j and k are integers of 0 or 1. A1 and A2 each independently represent a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl or amide group; multiple A2s may be the same or different; *1 is a bond bonded to the anhydride group of one party, and *2 is a bond bonded to the anhydride group of the other party.

6. The liquid crystal alignment agent according to claim 5, wherein, The expression (x-1) is selected from the group consisting of the following expressions (x1-1) to (x1-6). In equations (x1-1) to (x1-6), *1 is a bond bonded to the anhydride group of one side, and *2 is a bond bonded to the anhydride group of the other side.

7. The liquid crystal alignment agent according to claim 1, wherein, The diamine component comprises the diamine shown in formula (3) below. In equation (3), Ar1 and Ar 1’ Each represents a benzene ring, a biphenyl structure, or a naphthalene ring, wherein one or more hydrogen atoms on the benzene ring, the biphenyl structure, or the naphthalene ring are optionally substituted with monovalent groups; L1 and L 1’ Each represents a single bond, -O-, -C(=O)-, or -O-C(=O)-; A represents -CH2-, an alkylene group having 2 to 12 carbon atoms, or a divalent organic group formed by inserting at least any group among -O-, -C(=O)-O-, and -O-C(=O)- between the carbon-carbon bonds of the alkylene group; any hydrogen atom in A may optionally be replaced by a halogen atom.

8. A method for manufacturing a liquid crystal alignment film, comprising: The liquid crystal alignment agent as described in any one of claims 1 to 7 is coated onto a substrate, fired, and the resulting film is irradiated with radiation.

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

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

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

12. The liquid crystal display element according to claim 11, wherein, The liquid crystal display element is driven by either IPS or FFS.

13. A diimide diester compound, wherein, The diimide diester compound is any one of the compounds shown in formulas (b-1) to (b-6) and (b-8) below. 。 14. A polymer comprising one or more polyimide precursors selected from the group consisting of polyimide precursors and polyimides of imide derivatives thereof, wherein the polyimide precursor is obtained by polymerizing a tetracarboxylic acid derivative component comprising at least one compound selected from the group consisting of tetracarboxylic dianhydrides and their derivatives and a diimide diester compound represented by the following formula (1) with a diamine component, wherein the at least one compound selected from the group consisting of tetracarboxylic dianhydrides and their derivatives does not include a tetracarboxylic acid diimide diester compound. The polymer has groups derived from the diimide diester compound, represented by the following formula (1A). In formula (1), X1 represents a tetravalent organic group derived from acyclic aliphatic tetracarboxylic dianhydride or alicyclic tetracarboxylic dianhydride or their derivatives; R each independently represents a monovalent organic group with 1 to 5 carbon atoms. In formula (1A), R represents a monovalent organic group with 1 to 5 carbon atoms; * represents a bond bonded to X1.

15. The polymer according to claim 14, wherein, In the formula (1), X1 represents a tetravalent organic group derived from a tetracarboxylic acid dianhydride or its derivative having a noncyclic aliphatic hydrocarbon group with 4 to 16 carbon atoms or an alicyclic aliphatic hydrocarbon group with 4 to 16 carbon atoms.

16. The polymer according to claim 14, wherein, The diimide diester compound is any one of the compounds shown in formulas (b-1) to (b-6) and (b-8) below. 。

Images