Polymer and compound

Abstract

A polymer is a polymer (A) that is at least one type selected from the group consisting of polyimide precursors having a repeating unit (a1) represented by formula (1) and polyimides that are imides of the polyimide precursors. In formula (1), X1 represents a tetravalent organic group; y1 represents a divalent organic group represented by formula (H) and having three or more benzene rings; r and Z each independently represent a hydrogen atom or a monovalent organic group, in formula (H), L1 and L1'each independently represent a single bond,-O-,-S-,-C (= O)-,-O-C (= O)-or-C (= O)-NR-, in the-C (= O)-NR-, R represents a hydrogen atom or a monovalent organic group, A represents an alkylene group having 4-10 carbon atoms, and Ar1 and Ar1 'each independently represent a benzene ring, a biphenyl structure or a naphthalene ring; any hydrogen atom on the ring of Ar1 and Ar1 'may be substituted by a monovalent group, and * represents a bond.

Description

Polymers and compounds

[0001] This application is a divisional application of the following application: Invention title: Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element.

[0002] International application date: February 25, 2022.

[0003] International application number: PCT / JP2022 / 007826.

[0004] National application number: 202280019421.1. Technical Field

[0005] This invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element. Background Technology

[0006] 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).

[0007] Currently, the most widely used liquid crystal alignment film in industry is manufactured by brushing the surface of a film formed on an electrode substrate, which is composed of polyamic acid and / or polyimide formed by imidizing it, in one direction using a cloth such as cotton, nylon, or polyester. Brushing 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 brushing, such as damage to the alignment film surface, dust generation, mechanical stress, effects caused by static electricity, and inhomogeneities within the alignment surface. As an alternative to brushing, photoalignment, which imparts alignment capability to liquid crystals by irradiating them with polarized radiation, is known. Regarding photoalignment, methods utilizing photoisomerization reactions, photocrosslinking reactions, and photodecomposition reactions have been proposed (see, for example, Non-Patent Literature 1, Patent Literature 1, and Patent Literature 2).

[0008] Prior Art Documents: Patent Documents: Patent Document 1: Japanese Patent Application Publication No. Hei 9-297313; Patent Document 2: Japanese Patent Application Publication No. 2004-206091; Non-Patent Documents: Non-Patent Document 1: "Liquid Crystal Optical Alignment Film", Kido Waki, Ichimura Functional Materials, November 1997, Vol. 17, No. 11, pp. 13-22. Summary of the Invention

[0009] The problem this invention aims to solve is that, for liquid crystal alignment films used in IPS-driven and FFS-driven liquid crystal display elements, a high alignment constraint force is needed to suppress image retention (hereinafter also referred to as AC image retention) caused by long-term AC driving. Furthermore, when performing alignment processing using photo-alignment, the amount of light irradiation is a factor affecting energy consumption and production speed; therefore, it is preferable to perform alignment processing with a low amount of light irradiation.

[0010] However, the inventors conducted research and determined that, for liquid crystal alignment films that can achieve liquid crystal alignment with a small amount of light irradiation, the range of light irradiation required to obtain liquid crystal alignment films with small unevenness (non-uniformity) of the twist angle of the liquid crystal within the liquid crystal alignment film surface is narrow. Therefore, when pursuing larger screen sizes for liquid crystal display elements, the liquid crystal alignment becomes incomplete in a portion of the obtained liquid crystal alignment film. During long-term image display, the brightness within the surface may deviate, reducing the display quality level.

[0011] Therefore, 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, and a liquid crystal display element using the liquid crystal alignment film. The liquid crystal alignment agent can expand the range of light irradiation required to obtain a liquid crystal alignment film with small unevenness (non-uniformity) of the twist angle of the liquid crystal within the liquid crystal alignment film surface, thereby efficiently obtaining a high-quality liquid crystal alignment film. Furthermore, 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, and a liquid crystal display element using the liquid crystal alignment film. The liquid crystal alignment agent can expand the range of light irradiation required to obtain a liquid crystal alignment film capable of suppressing AC image retention, thereby efficiently obtaining a high-quality liquid crystal alignment film.

[0012] The inventors conducted in-depth research on solutions to the problem and discovered that the above-mentioned problem could be solved by using a liquid crystal alignment agent containing specific components, thus completing the present invention. Specifically, the following is the main content.

[0013] A liquid crystal alignment agent, characterized in that it contains a polymer (A), which is at least one selected from the group consisting of a polyimide precursor having a repeating unit (a1) as shown in the following formula (1) and a polyimide as an imide derivative of the polyimide precursor. (In formula (1), X1 represents a tetravalent organic group. Y1 is a divalent organic group with three or more benzene rings as shown in formula (H) below. R and Z each independently represent a hydrogen atom or a monovalent organic group.) (In formula (H), L1 and L 1’ Each can independently represent a single bond, -O-, -S-, -C(=O)-, -O-C(=O)-, or -C(=O)-NR- (R represents a hydrogen atom or a monovalent organic group).

[0014] A represents an alkylene group with 4 to 10 carbon atoms.

[0015] Ar1 and Ar 1’ Each can independently represent a benzene ring, biphenyl structure, or naphthalene ring. Ar1 and Ar 1’ Any hydrogen atom on the ring may be optionally replaced by a monovalent group. It should be noted that, throughout this specification, halogen atoms may include: fluorine, chlorine, bromine, iodine, etc., with * indicating a bond.

[0016] Effects of the Invention According to the present invention, a liquid crystal alignment agent, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element using the liquid crystal alignment film can be obtained. The liquid crystal alignment agent can expand the range of light irradiation for obtaining a liquid crystal alignment film with small unevenness (non-uniformity) of the twist angle of the liquid crystal within the liquid crystal alignment film surface, thus efficiently obtaining a liquid crystal alignment film of good quality. Furthermore, a liquid crystal alignment agent, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element using the liquid crystal alignment film can be obtained. The liquid crystal alignment agent can expand the range of light irradiation for obtaining a liquid crystal alignment film capable of suppressing AC image retention, thus efficiently obtaining a liquid crystal alignment film of good quality. Attached Figure Description

[0017] Figure 1 is a schematic cross-sectional view showing an example of a transverse electric field liquid crystal display element of the present invention.

[0018] Figure 2 is a schematic cross-sectional view showing another example of the transverse electric field liquid crystal display element of the present invention. Detailed Implementation

[0019] <Polymer (A)> The liquid crystal alignment agent of the present invention contains a polymer (A), which is selected from at least one group consisting of a polyimide precursor having a repeating unit (a1) shown in the following formula (1) and a polyimide as an imide derivative of the polyimide precursor. It should be noted that the polymer (A) may also be one or composed of two or more. (In formula (1), X1 represents a tetravalent organic group. Y1 is a divalent organic group having three or more benzene rings as shown in the following formula (H). R and Z each independently represent a hydrogen atom or a monovalent organic group.) More preferably, polymer (A) has the divalent organic group shown in the above formula (H) in the main chain direction of polymer (A). Furthermore, more preferably, polymer (A) has the benzene rings that Y1 has in the main chain direction of polymer (A).

[0020] The main chain of a polymer refers to the part composed of the longest atomic chains in the polymer.

[0021] Furthermore, "polymer (A) has the divalent organic group shown in formula (H) above in the main chain direction of polymer (A)" means that the longest atomic chain of the divalent organic group shown in formula (H) constitutes the main chain of polymer (A). In other words, "polymer (A) has the divalent organic group shown in formula (H) above in the main chain direction of polymer (A)" means that the two ends of the longest atomic chain of the divalent organic group shown in formula (H) are respectively bonded to two nitrogen atoms bonded to Y1 in formula (1).

[0022] Furthermore, it refers to the fact that at least two carbon atoms of each benzene ring in all the benzene rings of Y1 constitute the main chain of polymer (A).

[0023] Here, the benzene ring in "a divalent organic group having three or more benzene rings" also includes the benzene ring that forms a condensation ring. Furthermore, when counting the number of benzene rings in formula (H), the counting is performed as follows.

[0024] The naphthalene ring is assumed to have two benzene rings.

[0025] The biphenyl structure is assumed to have two benzene rings.

[0026] There is no particular limitation on the number of benzene rings in Y1 as long as there are three or more. For example, it can be three or more but less than eight, or three or more but less than six. From the viewpoint of properly obtaining the effects of the present invention, it can also be four or more but less than six. (In formula (H), L1 and L 1’ Each can independently represent a single bond, -O-, -S-, -C(=O)-, -O-C(=O)-, or -C(=O)-NR- (R represents a hydrogen atom or a monovalent organic group).

[0027] A represents an alkylene group having 4 to 10 carbon atoms, more preferably an alkylene group having 4, 6, 8 or 10 carbon atoms, and even more preferably an alkylene group having 4 or 6 carbon atoms.

[0028] Ar1 and Ar 1’Each can independently represent a benzene ring, biphenyl structure, or naphthalene ring. Ar1 and Ar 1’ Any hydrogen atom on the ring may be optionally replaced by a monovalent group. (As L1 and L above) 1’ The monovalent organic group in the R of the group "-C(=O)-NR-" can be listed as: alkyl with 1 to 3 carbon atoms, alkoxy with 1 to 3 carbon atoms, alkenyl with 2 to 3 carbon atoms, acyl with 2 to 3 carbon atoms, alkylsilyl with 1 to 3 carbon atoms, alkoxysilyl with 1 to 3 carbon atoms, tert-butoxycarbonyl, or a monovalent organic group in which a portion of the hydrogen atom of these groups is replaced by at least any one of a halogen atom and a hydroxyl group.

[0029] Ar1 and Ar in the above formula (H) 1’ For monovalent groups substituting any hydrogen atom on the ring, examples include: halogen atoms, alkyl groups having 1 to 3 carbon atoms, and alkyl groups having 1 to 3 carbon atoms formed by replacing at least a portion of the hydrogen atoms with at least any one of the aforementioned halogen atoms and hydroxyl groups; alkoxy groups having 1 to 3 carbon atoms, and alkoxy groups having 1 to 3 carbon atoms formed by replacing at least a portion of the hydrogen atoms with at least any one of the aforementioned halogen atoms and hydroxyl groups; alkenyl groups having 2 to 3 carbon atoms; acyl groups having 2 to 3 carbon atoms; alkylsilyl groups having 1 to 3 carbon atoms; alkoxysilyl groups having 1 to 3 carbon atoms; hydroxyl groups; nitrile groups; and other monovalent groups.

[0030] If we list the groups "*-L1-A-L" in the above formula (H) 1’ Specific examples of preferred groups include: group "*-(CH2)". n -*”, group "*-O-(CH2)" n -O-*”, group “*-C(=O)-(CH2)” n -C(=O)-*”, group "*-C(=O)-NR-(CH2)" n -O-*”, group “*-O-C(=O)-(CH2)” n -O-*”, group “*-O-C(=O)-(CH2)” n -O-C(=O)-*”, group “*-O-C(=O)-(CH2)” n -C(=O)-O-*”, group "*-S-(CH2)" n -S-*”, group "*-C(=O)-NR-(CH2)" n -NR-C(=O)-*”, group "*-C(=O)-O-(CH2)" n -O-C (=O)-*”, group "*-O-(CH2)" n -*”, group “*-S-(CH2) n-*" or the group "*-NR-C(=O)-(CH2)" n -C(=O)-NR-*""R represents a hydrogen atom or a monovalent organic group. Examples of such monovalent organic groups can be found in L1 and L" above." 1’ The structure exemplified in R is the group "-C(=O)-NR-". From the viewpoint of appropriately obtaining the effects of the present invention, the aforementioned group "*-L1-A-L" 1’ -*” is preferably the group “*-(CH2)”. n -*”, group "*-O-(CH2)" n -O-*”, group “*-O-(CH2” n -*".

[0031] n is an integer from 4 to 10, preferably an integer of 4, 6, 8 or 10, and more preferably an integer of 4 or 6.

[0032] From the viewpoint of properly obtaining the effects of the present invention, Y1 in the above formula (1) is preferably a divalent organic group represented by any of the following formulas (h-1) to (h-4). (In equations (h-1) to (h-4), R) a1 ~R a4 This represents a monovalent organic group. Specific examples include Ar1 and Ar in the above formula (H). 1’ The structure is illustrated by substituents on the hydrogen atoms of the ring. L represents the group "*-L1-A-L" in the above formula (H). 1’ -* (* represents a bond).

[0033] m are independent integers from 0 to 6, and n are independent integers from 0 to 4. In the case of multiple R... a1 ~R a4 In the case of, they may be either the same or different. ) As monovalent organic groups in R and Z in the above formula (1), the following can be listed: monovalent hydrocarbon groups with 1 to 20 carbon atoms; the methylene group of the hydrocarbon group is surrounded by -O-, -S-, -CO-, -COO-, -COS-, -NR 3 -、-CO-NR 3 -, -Si(R) 3 )2-(where R 3A monovalent group A formed by replacing hydrogen atoms or monovalent hydrocarbon groups with 1 to 10 carbon atoms, such as -SO2-; a monovalent group formed by replacing at least one hydrogen atom of the aforementioned monovalent hydrocarbon group or monovalent group A bonded to a carbon atom with a halogen atom, hydroxyl group, alkoxy group, nitro group, amino group, mercapto group, nitroso group, alkylsilyl group, alkoxysilyl group, silanol group, sulfinyl group, phospho group, carboxyl group, cyano group, sulfonyl group, acyl group, etc.; a monovalent group having a heterocyclic ring.

[0034] As the monovalent organic groups in R and Z in the above formula (1), preferably alkyl, alkenyl, alkynyl, tert-butoxycarbonyl or 9-fluorenoxycarbonyl with 1 to 10 carbon atoms, more preferably alkyl with 1 to 3 carbon atoms, and even more preferably methyl.

[0035] From the viewpoint of properly obtaining the effects of the present invention, R and Z are each independently preferred to be alkyl groups having 1 to 3 carbon atoms, more preferably hydrogen atoms or methyl groups.

[0036] From the viewpoint of properly obtaining the effects of the present invention, the polymer (A) described above may also be at least one polymer selected from the group consisting of a polyimide precursor having a repeating unit (a2) shown in formula (2) below and a polyimide as an imide derivative of the polyimide precursor. In other words, the polymer (A) described above may also further have at least any one of the repeating unit (a2) shown in formula (2) below and an imide structure of the repeating unit (a2) shown in formula (2) below. It should be noted that the repeating unit (a2) may also be one or composed of two or more. (In formula (2), X2 represents a tetravalent organic group. Y2 represents a divalent organic group as shown in formulas (o-1) to (o-14) below. R and Z have the same meaning as R and Z in formula (1) above.) (In formulas (o-13) to (o-14), the two m's are independent. Any hydrogen atom on the ring of the benzene ring, biphenyl structure, or naphthalene ring in formulas (o-1) to (o-14) may optionally be replaced by a monovalent group.) As for the monovalent group that serves as a substituent for any hydrogen atom on the ring of the benzene ring, biphenyl structure, or naphthalene ring in formulas (o-1) to (o-14), examples include: halogen atoms, alkyl groups having 1 to 3 carbon atoms, and alkyl groups having at least a portion of hydrogen atoms replaced by at least any of the aforementioned halogen atoms and hydroxyl groups; alkoxy groups having 1 to 3 carbon atoms and alkoxy groups having at least a portion of hydrogen atoms replaced by at least any of the aforementioned halogen atoms and hydroxyl groups; alkenyl groups having 2 to 3 carbon atoms; acyl groups having 2 to 3 carbon atoms; alkylsilyl groups having 1 to 3 carbon atoms, alkoxysilyl groups having 1 to 3 carbon atoms, hydroxyl groups, nitrile groups, and other monovalent groups.

[0037] From the viewpoint of properly obtaining the effects of the present invention, the polymer (A) described above may also be at least one polymer selected from the group consisting of a polyimide precursor and a polyimide as an imide derivative of the polyimide precursor, wherein the polyimide precursor further has at least one selected from the group consisting of a repeating unit (a2') shown in formula (2') and a repeating unit (a3) ​​shown in formula (3). In other words, the polymer (A) described above may also further have at least any one of the repeating unit (a2') shown in formula (2'), an imidized structure of the repeating unit (a2') shown in formula (2'), a repeating unit (a3) ​​shown in formula (3), and an imidized structure of the repeating unit (a3) ​​shown in formula (3). (In equations (2') and (3), X) 2’ X3 represents a tetravalent organic group, Y 2’ Y2 represents the divalent organic group shown in the following formula (O2), and Y3 represents a divalent organic group with 6 to 30 carbon atoms containing the group "-N(D)- (D represents a carbamate protecting group)". R and Z have the same meaning as R and Z in the above formula (1). In equation (O2), m represents an integer from 0 to 2. When m is 0, Ar 2’ Indicating a benzene ring or naphthalene ring, when m is 1 to 2, Ar 2’ Each element independently represents a benzene ring. Ar 2’ Any hydrogen atom on the ring may be optionally replaced by a monovalent group, such as the structures exemplified as monovalent groups that are substituents for any hydrogen atom of the benzene ring, biphenyl structure, or naphthalene ring in the above formulas (o-1) to (o-14). Q 2’ Indicates a single bond or -O-. In the presence of multiple Ar... 2’ and Q2’ In the case of multiple Ar 2’ and Q 2’ Each may be optionally the same or different. As the divalent organic group represented by the above formula (O2), from the viewpoint of minimizing the generation of AC residuals, it is preferable to be a divalent organic group formed by removing two amino groups from the following diamines, wherein the diamine is selected from p-phenylenediamine, m-phenylenediamine, 2,5-diaminotoluene, 2,5-diaminop-xylene, 1,4-diaminotrimethylbenzene, 1,4-diaminotetramethylbenzene, 1,4-diamino-2,5-methoxybenzene, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diphenylbenzene, etc. The group consisting of aminobiphenyl, 2,2'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 2,2'-dihydroxy-4,4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3-trifluoromethyl-4,4'-diaminobiphenyl, 2-trifluoromethyl-4,4'-diaminobiphenyl, 3-fluoro-4,4'-diaminobiphenyl, 2-fluoro-4,4'-diaminobiphenyl, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 2,6-diaminonaphthalene, and 1,5-diaminonaphthalene.

[0038] The D in Y3 above represents a urethane-based protecting group. Examples of urethane-based protecting groups include tert-butoxycarbonyl or 9-fluorenemethoxycarbonyl.

[0039] As a specific example of Y3 mentioned above, divalent organic groups represented by the following formula (Dx) can be listed. In formula (Dx), Q5 is a single bond and -(CH2). n - (n is an integer from 1 to 20), or - (CH2). n Any -CH2- is replaced by -O-, -Si(CH3)2-, -COO-, -OCO-, -NQ9-, -NQ9CO-, -CONQ9-, -NQ9CONQ 10 A group formed by substituting -, -NQ9COO- or -OCOO-, Q9 and Q 10Each of the following groups independently represents a hydrogen atom or a monovalent organic group; Q6 and Q7 independently represent -H, -NHD, -N(D)2, a group having -NHD, or a group having -N(D)2 (D represents a urethane protecting group). Wherein, when m=0, Q6 has a urethane protecting group; when m=1, at least one of Q5, Q6, and Q7 has a urethane protecting group in its group. Furthermore, in Q6 and Q7, when representing groups other than hydrogen atoms, the preferred number of carbon atoms is 1 to 8.

[0040] As mentioned above, Q9 and Q 10 Monovalent organic groups can be listed as: alkyl groups with 1 to 3 carbon atoms, alkenyl groups with 2 to 3 carbon atoms, alkynyl groups with 2 to 3 carbon atoms, and monovalent organic groups with 1 to 3 carbon atoms containing fluorine atoms.

[0041] As a preferred specific example of Y3, from the viewpoint of fewer AC residuals, any of the following formulas (Y3-1) to (Y3-9) can be listed as divalent organic groups. “Boc” represents tert-butoxycarbonyl. As for the aforementioned X1, X2, X 2’ And X3, which can be listed as a tetravalent organic group derived from acyclic aliphatic tetracarboxylic dianhydride or its derivatives, alicyclic tetracarboxylic dianhydride or its derivatives, or aromatic tetracarboxylic dianhydride or its derivatives.

[0042] Here, as derivatives of tetracarboxylic dianhydride, examples include: tetracarboxylic dihalides, tetracarboxylic dialkyl esters, and tetracarboxylic dialkyl ester dihalides.

[0043] More preferably, it is a tetravalent organic group derived from a tetracarboxylic dianhydride or a derivative thereof having at least one partial structure selected from the group consisting of a cyclobutane ring structure, a cyclopentane ring structure, and a cyclohexane ring structure. If X1, X2, X... are listed... 2’ Specific examples of preferred X3, besides the tetravalent organic group shown in formula (g) below, include: any tetravalent organic group shown in formulas (X-1) to (X-25) below, tetravalent organic groups derived from aromatic tetracarboxylic acid dianhydrides, etc. From the viewpoint of appropriately obtaining the effects of the present invention, X1, X2, X... 2’ X3 is more preferably a tetravalent organic group as shown in formula (g), (X-1) to (X-5), (X-11), (X-21) to (X-23), and even more preferably a tetravalent organic group as shown in formula (g). (In formula (g), R1 to R4 each 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 with 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group, and at least one of R1 to R4 represents a group other than a hydrogen atom as defined above.) Specific examples of alkyl groups having 1 to 6 carbon atoms in R1 to R4 of the above formula (g) include: methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, etc. Specific examples of alkenyl groups having 2 to 6 carbon atoms in R1 to R4 include: vinyl, propenyl, butenyl, etc., which are optionally linear or branched. Specific examples of alkynyl groups having 2 to 6 carbon atoms in R1 to R4 include, for example: ethynyl, 1-propynyl, 2-propynyl, etc. Specific examples of monovalent organic groups having 1 to 6 carbon atoms containing fluorine atoms in R1 to R4 include: fluoromethyl, trifluoromethyl, pentafluoroethyl, pentafluoropropyl, etc. Regarding more preferred combinations of R1 to R4, from the viewpoint of high photoreactivity, R1 to R4 are hydrogen atoms or methyl groups; preferably, at least one of R1 to R4 is methyl; more preferably, at least two of R1 to R4 are methyl groups. Further preferred cases are those where R1 and R4 are methyl groups and R2 and R3 are hydrogen atoms.

[0044] Here, aromatic tetracarboxylic acid dianhydrides refer to acid dianhydrides obtained by intramolecular dehydration of carboxyl groups bonded to aromatic rings such as benzene rings and naphthalene rings. Specific examples include: tetravalent organic groups represented by any of the following formulas (Xa-1) to (Xa-2), and tetravalent organic groups represented by any of the following formulas (Xr-1) to (Xr-7). (In formulas (Xa-1) and (Xa-2), x and y are each independently a single bond, ether bond, carbonyl group, ester bond, alkylene group with 1 to 10 carbon atoms, 1,4-phenylene group, sulfonyl group, or amide bond. j and k are integers of 0 or 1.) The tetravalent organic group shown in the above formula (Xa-1) or (Xa-2) can also be any of the structures shown in the following formulas (Xa-3) to (Xa-19). The polymer (A) described above may also be at least one polymer selected from the group consisting of a polyimide precursor and a polyimide as an imide derivative of the polyimide precursor, wherein the polyimide precursor has, in addition to having the repeating unit (a1), repeating unit (a2), repeating unit (a2') and repeating unit (a3) ​​described above, a repeating unit (a4) shown in the following formula (4). In formula (4), X4 represents a tetravalent organic group, and Y4 represents a divalent organic group other than the divalent organic group shown in formula (H) above, the divalent organic groups shown in formulas (o-1) to (o-14) above, the divalent organic groups with 6 to 30 carbon atoms containing the above group "-N(D)- (D represents a carbamate protecting group)", and the divalent organic group shown in formula (O2) above. R and Z have the same meaning as R and Z in formula (1) above.

[0045] As a specific example of X4, examples can be listed in the above X1, X2, X... 2’ And the tetravalent organic group exemplified in the description of X3. From the viewpoint of properly obtaining the effects of the present invention, X4 is preferably a tetravalent organic group shown in formula (g) above or a tetravalent organic group shown in any of the formulas (X-1) to (X-25) above, more preferably a tetravalent organic group shown in formula (g), (X-1) to (X-5), (X-11), (X-21) to (X-23) above, and even more preferably a tetravalent organic group shown in formula (g) above.

[0046] Y4 represents a divalent organic group other than the divalent organic group shown in formula (H) above, the divalent organic groups shown in formulas (o-1) to (o-14) above, the divalent organic group with 6 to 30 carbon atoms having the group "-N(D)- (D represents a carbamate protecting group)" in the molecule, and the divalent organic group shown in formula (O2) above (hereinafter also referred to as other divalent organic groups). As such other divalent organic groups, divalent organic groups formed by removing two amino groups from the following diamines can be listed.

[0047] Examples of divalent organic groups formed by removing two amino groups from the following diamines include: groups represented by any of the formulas (Y-1) to (Y-167) as described in WO2018 / 117239: 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane; diamines having photo-oriented groups, such as the diamines represented by formulas (g-1) to (g-10); diamines having urea bonds, such as the diamines represented by formulas (u-1) to (u-3) (wherein, the diamine does not have an intramolecular carbamate protecting group); diamines having amide bonds, such as the diamines represented by formulas (u-4) to (u-8) (wherein, the diamine does not have an intramolecular carbamate protecting group); and heterocycles selected from nitrogen atoms and groups "*". 21 -NR-* 22 (*) 21 and* 22This indicates a bond bonded to a carbon atom constituting an aromatic ring. The carbon atom does not form a ring with the nitrogen atom bonded to R. R represents a hydrogen atom or a monovalent organic group (the aforementioned monovalent organic group is bonded to a nitrogen atom via a carbon atom other than a carbonyl carbon). The diamine is composed of at least one nitrogen-containing structure (hereinafter also referred to as a nitrogen-containing structure) from the group consisting of amino groups; 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol; 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, 4,4'-diaminobiphenyl-3-carboxylic acid, 4,4'-diaminodiphenylmethane-3-carboxylic acid, 4,4'-diaminodiphenylethane-3-carboxylic acid, 4,4'-diaminobiphenyl-3,3'-dicarboxylic acid, Diamines with carboxyl groups, such as 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, 4,4'-diaminodiphenylethane-3,3'-dicarboxylic acid, and 4,4'-diaminodiphenyl ether-3,3'-dicarboxylic acid; 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 4,4'-diaminobenzophenone, and 1-(4-aminophenyl)-1,3,3-trimethyl-1H-indane-5-amine. 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine; diamines with photopolymerizable groups at the ends, such as 2-(2,4-diaminophenoxy)ethyl methacrylate and 2,4-diamino-N,N-diallyl aniline; 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 lanosteryl ester of 3,6-bis(4-aminobenzoyloxy)cholesteryl ester. Diamines with a steroidal skeleton, such as steranes; diamines represented by formulas (V-1) to (V-6) below; diamines with siloxane bonds, such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane; diamines with an oxazoline ring structure, such as formulas (Ox-1) to (Ox-2) below; diamines with free radical polymerization initiator functions, such as 1-(4-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylacetone, 2-(4-(2-hydroxy-2-methylpropionyl)phenoxy)ethyl ester of 3,5-diaminobenzoic acid, 4,4'-diaminobenzophenone, and 3,3'-diaminobenzophenone. (In the above formulas (V-1) to (V-6), X) v1 ~Xv4 and X p1 ~X p2 Each can be represented independently as – (CH2) a - (a is an integer from 1 to 15), -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -CH2O-, -CH2-OCO-, -COO- or -OCO-, X v5 This represents -O-, -CH2O-, -CH2-OCO-, -COO-, or -OCO-. X a Represents single bonds, -O-, -NH-, -O- (CH2). m -O- (m represents an integer from 1 to 6), -C(CH3)2-, -CO-, -(CH2) m - (m represents an integer from 1 to 6), -SO2-, -O-C(CH3)2-, -CO-(CH2) m - (m represents an integer from 1 to 6), -NH- (CH2) m - (m represents an integer from 1 to 6), -SO2-(CH2) m - (m represents an integer from 1 to 6), -CONH- (CH2) m - (m represents an integer from 1 to 6), -CONH- (CH2) m -NHCO- (m represents an integer from 1 to 6), -COO- (CH2) m -OCO- (m represents an integer from 1 to 6), -CONH-, -NH- (CH2) m -NH- (m represents an integer from 1 to 6) or -SO2- (CH2) m -SO2- (m represents an integer from 1 to 6), R v1 ~R v4 and R 1a ~R 1b Each can be independently represented as an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms. Examples of nitrogen-containing heterocycles include: pyrrole, imidazole, pyrazole, triazole, pyridine, pyrimidine, pyridazine, pyrazine, indole, benzimidazole, purine, quinoline, isoquinoline, naphthidine, quinoxaline, phthalazine, triazine, carbazole, acridine, piperidine, piperazine, pyrrolidine, hexamethyleneimine, etc. Among these, pyridine, pyrimidine, pyrazine, piperidine, piperazine, quinoline, carbazole, or acridine are preferred.

[0048] As the above-mentioned group "*" 21 -NR-* 22The R in the text represents a monovalent organic group, which is a monovalent hydrocarbon group with 1 to 10 carbon atoms, a monovalent group formed by inserting -O- or -C (=O)- between a portion of the carbon-carbon bond of the hydrocarbon group, or a monovalent organic group formed by replacing a portion of the hydrogen atoms of the above-mentioned hydrocarbon group and the above-mentioned monovalent group with halogen atoms or hydroxyl groups. R is preferably a hydrogen atom or a methyl group.

[0049] Specific examples of diamines having a nitrogen-containing structure include: 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-diaminoacridine, compounds represented by formulas (Dp-1) to (Dp-8) below, or compounds represented by formulas (z-1) to (z-13) below. From the viewpoint of properly obtaining the effects of the present invention, the aforementioned other divalent organic groups are preferably divalent organic groups without a side chain structure having 4 or more carbon atoms. Examples of such divalent organic groups without a side chain structure having 4 or more carbon atoms include divalent organic groups formed by removing two amino groups from diamines selected from the group consisting of diamines excluding 2-(2,4-diaminophenoxy)ethyl methacrylate, 2,4-diamino-N,N-diallyl aniline, the aforementioned diamines having a steroidal skeleton, the diamines shown in formulas (V-1) to (V-6), 1-(4-(2-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylacetone, 2-(4-(2-hydroxy-2-methylpropionyl)phenoxy)ethyl 3,5-diaminobenzoic acid, N-phenyl-3,6-diaminocarbazole, and diamines shown in (z-4) and (z-6).

[0050] From the viewpoint of properly obtaining the effects of the present invention, polymer (A) preferably contains the repeating unit (a1) and the imidized structure of the repeating unit (a1) in a manner totaling 5 to 100 mol% of all repeating units, and more preferably in a manner totaling 10 to 100 mol% of all repeating units. It should be noted that the total here also includes cases where any one of the repeating unit (a1) and the imidized structure of the repeating unit (a1) is 0 mol%. When total is also mentioned below, it also includes cases where one or more of the constituent elements are 0 mol%.

[0051] When polymer (A) contains repeating units other than repeating unit (a1) and imidized structure of repeating unit (a1), polymer (A) preferably contains repeating unit (a1) and imidized structure of repeating unit (a1) in a manner that totals less than 95 mol% of all repeating units, more preferably contains repeating unit (a1) and imidized structure of repeating unit (a1) in a manner that totals less than 90 mol% of all repeating units, and even more preferably contains repeating unit (a1) and imidized structure of repeating unit (a1) in a manner that totals less than 80 mol% of all repeating units.

[0052] From the viewpoint of properly obtaining the effects of the present invention, polymer (A) preferably contains repeating unit (a2) and the imidized structure of repeating unit (a2) in a manner that totals 5 mol% or more of all repeating units, more preferably contains repeating unit (a2) and the imidized structure of repeating unit (a2) in a manner that totals 10 mol% or more of all repeating units, and even more preferably contains repeating unit (a2) and the imidized structure of repeating unit (a2) in a manner that totals 20 mol% or more of all repeating units. Furthermore, the upper limit is preferably 90 mol%, more preferably 85 mol%.

[0053] From the viewpoint of properly obtaining the effects of the present invention, the polymer (A) preferably contains repeating units (a1) and (a2) and their imidized structures in a total of 10 mol% or more of all repeating units, more preferably 20 mol% or more of all repeating units. When the polymer (A) contains repeating units other than repeating units (a1) and (a2) and their imidized structures, the upper limit of the total number of repeating units (a1) and (a2) and their imidized structures is preferably 95 mol%, more preferably 90 mol%.

[0054] In the case where polymer (A) comprises at least any one of the repeating unit (a2') and the imidized structure of the repeating unit (a2'), from the viewpoint of properly obtaining the effects of the present invention, polymer (A) preferably comprises the imidized structure of the repeating unit (a2') and the repeating unit (a2') in a manner totaling 1 to 50 mol% of all repeating units, more preferably in a manner totaling 1 to 40 mol% of all repeating units, and even more preferably in a manner totaling 1 to 30 mol% of all repeating units. In the case where polymer (A) comprises at least any one of the repeating unit (a1) and its imidized structure and at least any one of the repeating unit (a2') and its imidized structure, the minimum value of the total amount of the repeating unit (a1) and the repeating unit (a2') and their imidized structures is preferably 5 mol%, more preferably 10 mol%.

[0055] From the viewpoint of properly obtaining the effects of the present invention, the polymer (A) comprises: at least any one of repeating units (a1) and their imidized structures, at least any one of repeating units (a2) and their imidized structures, and at least any one of repeating units (a2') and their imidized structures. The total of the repeating units (a1), (a2), and (a2') and their imidized structures is preferably 30 mol% or more, more preferably 40 mol% or more. When the polymer (A) comprises repeating units other than the repeating units (a1), (a2), and (a2') and their imidized structures, the upper limit of the total of the repeating units (a1), (a2), and (a2') and their imidized structures is preferably 95 mol%, more preferably 90 mol%.

[0056] In cases where the polymer (A) comprises at least any one of the repeating unit (a3) ​​and the imidized structure of the repeating unit (a3), from the viewpoint of properly obtaining the effects of the present invention, the polymer (A) preferably comprises the repeating unit (a3) ​​and the imidized structure of the repeating unit (a3) ​​in a manner totaling 1 to 40 mol% of all repeating units, more preferably in a manner totaling 1 to 30 mol% of all repeating units, and even more preferably in a manner totaling 1 to 25 mol% of all repeating units.

[0057] The polymer (A) may also contain repeating units (a2') and repeating units (a3) ​​and at least any of their imidized structures.

[0058] <Polymer (B)> In addition to the polymer (A) described above, the liquid crystal alignment agent of the present invention may also contain a polymer (B) that does not have the repeating unit (a1) and its imidized structure within the molecule. It should be noted that polymer (B) may be one or composed of two or more. From the viewpoint of properly obtaining the effects of the present invention, polymers having the repeating unit or its imidized structure shown in the following formula (5) can be listed as polymer (B). Furthermore, the repeating unit or its imidized structure constituting polymer (B) may be one or composed of two or more. (In formula (5), X5 is a tetravalent organic group and Y5 is a divalent organic group. R and Z have the same meaning as R and Z in formula (1) above.) As the tetravalent organic group in X5 above, examples can be listed as: a tetravalent organic group derived from acyclic aliphatic tetracarboxylic dianhydride or its derivatives, a tetravalent organic group derived from alicyclic tetracarboxylic dianhydride or its derivatives, or a tetravalent organic group derived from aromatic tetracarboxylic dianhydride or its derivatives. As specific examples, the tetravalent organic groups exemplified in X1 above can be listed. From the viewpoint of properly obtaining the effects of the present invention, and from the viewpoint of improving liquid crystal orientation, the acyclic aliphatic or alicyclic tetracarboxylic dianhydride or its derivatives are preferably tetracarboxylic dianhydride or its derivatives having at least one partial structure selected from the group consisting of cyclobutane ring structure, cyclopentane ring structure and cyclohexane ring structure. More preferably, X5 is a tetravalent organic group shown in formula (g) above, a tetravalent organic group shown in any of the formulas (X-1) to (X-25) above, a tetravalent organic group shown in formulas (Xa-1) to (Xa-2) above, or a tetravalent organic group shown in formulas (Xr-1) to (Xr-7) above (these are also collectively referred to as specific tetravalent organic groups).

[0059] From the viewpoint of properly obtaining the effects of the present invention, polymer (B) preferably contains, in a manner of 5 mol% or more of all repeating units contained in polymer (B), repeating units of formula (5) with X5 being the aforementioned specific tetravalent organic group, or their imidized structures, more preferably, repeating units of formula (5) with X5 being the aforementioned specific tetravalent organic group, in a manner of 10 mol% or more of all repeating units contained in polymer (B).

[0060] As divalent organic groups in Y5 above, examples of divalent organic groups exemplified in Y4 above can be listed. From the viewpoint of minimizing residual DC, polymer (B) is preferably a polymer containing a repeating unit or its imidized structure of formula (5) in which Y5 is a divalent organic group formed by removing two amino groups from the following diamines (also collectively referred to as specific divalent organic groups), said diamine being: the diamine having a urea bond, the diamine having an amide bond, the diamine having a nitrogen-containing structure, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, the diamine having a carboxyl group, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, p-phenylenediamine, and m-phenylenediamine.

[0061] From the viewpoint of improving transmittance, polymer (B) is more preferably having two or more repeating units or imidized structures of the above formula (5), including: at least any one of the repeating units and imidized structures of formula (5) having Y5 as a divalent organic group formed by removing two amino groups from a diamine; and at least any one of the repeating units and imidized structures of formula (5) having Y5 as a divalent organic group formed by removing two amino groups from a diamine other than the above, wherein the diamine is: the above-mentioned diamine having a urea bond, the above-mentioned diamine having an amide bond, or the above-mentioned diamine having a structure containing a nitrogen atom.

[0062] From the viewpoint of minimizing residual DC, polymer (B) may contain repeating units of formula (5) with Y5 as the aforementioned specific divalent organic group and their imidized structures in an amount of 1 mol% or more of all repeating units contained in polymer (B), or may contain repeating units of formula (5) with Y5 as the aforementioned specific divalent organic group and their imidized structures in an amount of 5 mol% or more of all repeating units contained in polymer (B). More preferably, it is 10 mol% or more, and even more preferably, it is 20 mol% or more.

[0063] From the perspective of minimizing residual images originating from residual DC, the ratio of polymer (A) to polymer (B) in the liquid crystal alignment agent, expressed as the mass ratio of [polymer (A)] to [polymer (B)], can be 10 / 90 to 90 / 10, 20 / 80 to 90 / 10, or 20 / 80 to 80 / 20.

[0064] <Methods for manufacturing polyamic acid, polyamic acid ester and polyimide> The polyamic acid ester and polyamic acid used as polyimide precursors and the polyimide as their imide derivatives used in this invention can be synthesized, for example, by a known method as described in WO2013 / 157586.

[0065] More specifically, this is carried out by reacting the diamine component with the tetracarboxylic acid derivative component in a solvent via a (condensation) reaction. Examples of the aforementioned tetracarboxylic acid derivative component include: tetracarboxylic dianhydride and its derivatives (tetracarboxylic acid dihalides, tetracarboxylic acid diesters, or tetracarboxylic acid diester dihalides). When a portion of polymer (A) or (B) contains an ammonium acid structure, a polymer having an ammonium acid structure (polyamic acid) is obtained, for example, by reacting the tetracarboxylic dianhydride component with the diamine component. The solvent is not particularly limited as long as it dissolves the resulting polymer.

[0066] Specific examples of the solvents mentioned above 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 solvents shown in formulas [D-1] to [D-3] below can be used. (In formula [D-1], D) 1 In formula [D-2], D represents an alkyl group having 1 to 3 carbon atoms. 2 In formula [D-3], D represents an alkyl group having 1 to 3 carbon atoms. 3 (This refers to alkyl groups having 1 to 4 carbon atoms.) These solvents can be used alone or in mixtures. Moreover, even solvents that do not dissolve polymers can be mixed with the above solvents as long as the resulting polymer does not precipitate.

[0067] When the diamine component reacts with the tetracarboxylic acid derivative component in a solvent, the reaction can be carried out at any concentration, preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction can be carried out at a high concentration initially, followed by the addition of solvent.

[0068] 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 to 1.2. Similar to conventional polycondensation reactions, the closer this molar ratio is to 1.0, the larger the molecular weight of the resulting polymers (A) and (B).

[0069] Polyamates can be obtained, for example, by known methods such as: [I] reacting the polyamic acid obtained by the above method with an esterifying agent; [II] reacting a tetracarboxylic acid diester with a diamine; [III] reacting a tetracarboxylic acid diester dihalide with a diamine.

[0070] Examples of methods for obtaining polyimide include thermal imidization, which involves heating a solution of the polymer obtained by the above reaction while maintaining it in that state; and catalytic imidization, which involves adding a catalyst to a solution of the polymer.

[0071] With regard to the polyimides in polymers (A) and (B) of the present invention, some or all of the repeating units of the aforementioned polyimide precursor are closed-ringed. In the aforementioned polyimides, the imidization rate is preferably 20-95%, more preferably 30-95%, and even more preferably 50-95%.

[0072] <Polymer Solution Viscosity / Molecular Weight> Regarding the polyamic acid, polyamic acid ester, and polyimide used in this invention, from an operational point of view, a solution viscosity of 10 to 1000 mPa·s is preferred when preparing a solution with a concentration of 10 to 15% by mass, but there is no particular limitation. It should be noted that the above-mentioned polymer solution viscosity (mPa·s) is a value measured using an E-type rotational viscometer at 25°C for a polymer solution with a concentration of 10 to 15% by mass prepared using a good solvent for the polymer (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0073] The weight-average molecular weight (Mw) of the polyamic acid, polyamic acid ester, and polyimide, as determined by gel permeation chromatography (GPC), converted from polystyrene, is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. 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 orientation and stability of the liquid crystal display element can be ensured.

[0074] <Capping Agent> When synthesizing polymers (A) and (B) of this invention, a suitable capping agent can also be used in conjunction with the tetracarboxylic acid derivative component and the diamine component as described above to synthesize capped polymers. Capped polymers have the effect of increasing the film hardness of the liquid crystal alignment film obtained by coating and improving the adhesion properties between the sealant and the liquid crystal alignment film.

[0075] Examples of the ends of polymers (A) and (B) in this invention include: amino, carboxyl, anhydride, or groups derived from the capping agent described later. Amino, carboxyl, and anhydride groups can be obtained through conventional condensation reactions or by capping the ends using the capping agents described below.

[0076] 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; and aniline. 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.

[0077] The proportion of the capping agent used relative to 100 moles of the total diamine components used is preferably 0.01 to 20 moles, more preferably 0.01 to 10 moles.

[0078] <Liquid Crystal Alignment Agent> The liquid crystal alignment agent of the present invention contains polymer (A) and, if necessary, polymer (B). In addition to polymer (A) and polymer (B), the liquid crystal alignment agent of the present invention may also contain other polymers. Specific examples of other polymers include polymers selected from the group consisting of polysiloxanes, polyesters, polyamides, polyureas, polyurethanes, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene derivatives, poly(styrene-maleic anhydride) copolymers, poly(isobutylene-maleic anhydride) copolymers, poly(vinyl ether-maleic anhydride) copolymers, poly(styrene-phenylmaleimide) derivatives, and poly(meth)acrylates. Specific examples of poly(styrene-maleic anhydride) copolymers include SMA1000, 2000, 3000 (manufactured by Cray Valley), and GSM301 (manufactured by Gifu Shellac Manufacturing). Examples of poly(isobutylene-maleic anhydride) copolymers include ISOBAM-600 (manufactured by Kuraray). Examples of poly(vinyl ether-maleic anhydride) copolymers include Gantrez AN-139 (methyl vinyl ether maleic anhydride resin, manufactured by Ashland). Other polymers can be used alone, or in combination of two or more.

[0079] The proportion of other polymers is preferably 90 parts by mass or less, more preferably 10 to 90 parts by mass, and even more preferably 20 to 80 parts by mass, relative to 100 parts by mass of the total polymers contained in the liquid crystal alignment agent.

[0080] The liquid crystal alignment agent is used to produce a liquid crystal alignment film, and from the viewpoint of forming a uniform film, it is preferably 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 organic solvent is preferred. In this case, the concentration of the polymer in the liquid crystal alignment agent can be appropriately varied according to the desired thickness of the coating film. From the viewpoint of forming a uniform and defect-free coating film, the concentration of the polymer in the liquid crystal alignment agent is preferably 1% by mass or more, and from the viewpoint of the storage stability of the solution, it is preferably 10% by mass or less. A particularly preferred polymer concentration is 2 to 8% by mass.

[0081] The organic solvent contained in the liquid crystal alignment agent is not particularly limited as long as it uniformly dissolves the polymer components. Specific examples include: N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllacticamide, N,N-dimethylpropionamide, tetramethylurea, N,N-diethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, and 3-methoxy-N,N-dimethyl... Acrylamide, 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, and N-cyclohexyl-2-pyrrolidone (also collectively referred to as "good solvents"). Preferably, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, or γ-butyrolactone. 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.

[0082] Furthermore, the organic 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). The content of the poor solvent is preferably 1 to 80% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass. The type and content of the poor solvent are appropriately selected according to the coating apparatus, coating conditions, coating environment, etc. of the liquid crystal alignment agent. Specific examples of the poor solvents used are described below, but are not limited thereto.

[0083] 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-dibutoxyethane, 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 monomethyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol, 2-(2-butoxy) Ethoxy-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 monopropyl ether, 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, cyclohexyl acetate, 4-methyl-2-pentyl 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.

[0084] Among them, diisobutylmethanol, 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.

[0085] 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-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone and propylene glycol diacetate; N,N-dimethyllactic acid and diisobutyl ketone; N-methyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-methyl-2-pyrrolidone, ethyl 3-ethoxypropionate, and... and dipropylene glycol monomethyl ether; N-ethyl-2-pyrrolidone, ethyl 3-ethoxypropionate and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether; N-ethyl-2-pyrrolidone, ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether; N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether acetate; N-ethyl-2-pyrrolidone and dipropylene glycol dimethyl ether; N,N-dimethyl lactamide and ethylene glycol monobutyl ether; N,N-dimethyl lactamide and propylene glycol diacetate; N-ethyl-2-pyrrolidone and diethylene glycol diethyl ether; N-ethyl-2-pyrrolidone, diethylene glycol monoethyl ether and butyl cellosolve acetate, N-methyl-2-pyrrolidone Ketones, diethylene glycol monomethyl ethers, and butyl cellosolve acetate; N,N-dimethyl lactamide and diethylene glycol diethyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and diethylene glycol diethyl ether; N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone, and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and diisobutyl ketone; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and dipropylene glycol monomethyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and diisobutyl ketone; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and dipropylene glycol monomethyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and diisobutyl ketone; N-methyl-2-pentanone and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; N-ethyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol dimethyl ether; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and propylene glycol diacetate; 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; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, and dipropylene glycol monomethyl ether; N-ethyl-2-pyrrolidone, diethylene glycol diethyl ether, and dipropylene glycol monomethyl ether; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, and propylene glycol diacetate; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, and diisobutyl ketone; N-ethyl-2-pyrrolidone, γ-butyrolactone, and diisobutyl ketone; N-ethyl-2-pyrrolidone, N... N-Dimethyllactic acid and diisobutyl ketone; N-Methyl-2-pyrrolidone, ethylene glycol monobutyl ether and ethylene glycol monobutyl ether acetate; γ-Butyrolactone, ethylene glycol monobutyl ether acetate and dipropylene glycol dimethyl ether; N-Ethyl-2-pyrrolidone, ethylene glycol monobutyl ether acetate and propylene glycol dimethyl ether; N-Methyl-2-pyrrolidone, 4-methyl-2-pentyl acetate and ethylene glycol monobutyl ether; N-Ethyl-2-pyrrolidone, cyclohexyl acetate, diacetone alcohol cyclohexanone and propylene glycol monomethyl ether; cyclopentanone and propylene glycol monomethyl ether; N-Methyl-2-pyrrolidone, cyclohexanone and propylene glycol monomethyl ether, etc.

[0086] 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 organic solvents. Examples of such additive components include: 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; compounds for improving the strength of the liquid crystal alignment film (hereinafter also referred to as crosslinking compounds); compounds for promoting imidization; and dielectrics and conductive materials for adjusting the dielectric constant and resistance of the liquid crystal alignment film.

[0087] From the viewpoint of exhibiting good resistance to AC remnants and significantly improving film strength, the aforementioned crosslinking compound can be at least one compound selected from the group consisting of: compounds having at least one group selected from the group consisting of ethylene oxide, oxetane, protected isocyanate group, protected isothiocyanate group, a group containing an oxazoline ring structure, a group containing a Michaelis acid structure, a cyclic carbonate group, and a hydroxyalkylamide bond; and phenolic compounds having at least one of alkoxymethyl and hydroxymethyl.

[0088] Specific examples of compounds containing ethylene oxide include: ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol diglycidyl ether, 2,2-dibromonepentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, and 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); hydrogenated bisphenol A type epoxy resins such as YX-8000 (manufactured by MITSUBISHI CHEMICAL); and YX6954BH30 (manufactured by MITSUBISHI CHEMICAL). Epoxy resins containing a biphenyl backbone, such as those manufactured by CHEMICAL; linear phenolic epoxy resins such as EPPN-201 (manufactured by Nippon Kayaku Co., Ltd.); linear phenolic epoxy resins such as EOCN-102S (manufactured by Nippon Kayaku Co., Ltd.) (ortho-, meta-, and para-)cresols; triglycidyl isocyanurate such as TEPIC (manufactured by Nissan Chemical Co., Ltd.); alicyclic epoxy resins such as CELLOXIDE2021P (manufactured by Daicel Chemical Industries); N,N,N',N'-tetraglycidyl-m-phenylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, and tetra(glycidyloxymethyl)methane.

[0089] Specific examples of compounds having oxetane groups include compounds having two or more oxetane groups as described in paragraphs 0170 to 0175 of WO2011 / 132751.

[0090] Specific examples of compounds having protected isocyanate groups include: compounds having two or more protected isocyanate groups as described in paragraphs 0046 and 0047 of Japanese Patent Application Publication No. 2014-224978, and compounds having three or more protected isocyanate groups as described in paragraphs 0119 and 0120 of WO2015 / 141598. Commercially available products preferably 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).

[0091] Specific examples of compounds having protected isothiocyanate groups include compounds having two or more protected isothiocyanate groups as described in Japanese Patent Application Publication No. 2016-200798.

[0092] Specific examples of compounds having groups containing an oxazoline ring structure include compounds containing two or more oxazoline ring structures as described in paragraph 0115 of Japanese Patent Application Publication No. 2007-286597.

[0093] Specific examples of compounds having groups containing Michaelis acid structures include compounds having two or more Michaelis acid structures as described in WO2012 / 091088.

[0094] Specific examples of compounds having cyclic carbonate groups include the compounds described in WO2011 / 155577.

[0095] Specific examples of compounds having hydroxyalkylamide bonds include: compounds having two or more groups shown in formula (d) below, as described in paragraph 0058 of Japanese Patent Application Publication No. WO2015 / 072554 and Japanese Patent Application Publication No. 2016-118753, and compounds described in Japanese Patent Application Publication No. 2016-200798. (R2 and R3 are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or "*-CH2-OH".) As a specific example of the above-mentioned phenolic compounds having at least one of alkoxyalkyl and hydroxymethyl, the compounds described in WO2010 / 074269 can be cited.

[0096] The above-described compound is an example of a cross-linking compound, but is not limited thereto. For example, other components not described above may be listed in publication No. WO2015 / 060357, from page 53, paragraph 0105 to page 55, paragraph 0116. Furthermore, two or more cross-linking compounds may be combined.

[0097] Of the aforementioned crosslinking compounds, N,N,N',N'-tetraglycidyl-m-phenylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, and TAKENATE are preferred. B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, B-882N, 1,3,5-tris(2-hydroxyethyl)isocyanurate, triglycidyl isocyanurate, 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-dimethoxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)-1,1,1,3,3,3-hexafluoropropane.

[0098] The content of the crosslinking compound in the liquid crystal alignment agent of the present invention 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. From the viewpoint of promoting the progress of the crosslinking reaction and exhibiting good resistance to AC image retention, it is more preferably 1 to 15 parts by mass.

[0099] 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, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropylmethyl Silane coupling agents including 3-dimethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-epoxypropoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris-(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanate-propyltriethoxysilane. When using a silane coupling agent, from the viewpoint of exhibiting good resistance to AC image retention, the polymer component contained in the liquid crystal alignment agent is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, relative to 100 parts by mass of the polymer component.

[0100] As the compounds used to promote imidization, compounds having a basic site (e.g., primary amino group, aliphatic heterocycle (e.g., pyrrolidine skeleton), aromatic heterocycle (e.g., imidazole ring, indole ring), or guanidine group, etc.) are preferred (excluding the aforementioned crosslinking compounds and binding aids); or compounds that generate the aforementioned basic site during calcination. More preferably, compounds that generate the aforementioned basic site during calcination are preferred; specific examples include compounds shown in formulas (B-1) to (B-17) below. The content of the compound used to promote imidization is preferably 2 moles or less, more preferably 1 mole or less, and even more preferably 0.5 moles or less, relative to 1 mole of the amic acid or amic acid ester site of the polymer (A). (D represents an organic group that is removed by heating, preferably tert-butoxycarbonyl or 9-fluorenoxycarbonyl.) The concentration of solid components in the liquid crystal alignment agent (the proportion of the total mass of components other than the solvent in the total mass of the liquid crystal alignment agent) should be appropriately selected considering viscosity, volatility, etc., and is preferably in the range of 1 to 10% by mass.

[0101] The particularly preferred range of solid component concentration varies depending on the method used to coat the liquid crystal alignment agent onto the substrate. For example, when using spin coating, the solid component concentration is particularly preferably in the range of 1.5 to 4.5% by mass. When using printing, the solid component concentration is particularly preferably in the range of 3 to 9% by mass, thereby setting the solution viscosity to the range of 12 to 50 mPa·s. When using inkjet printing, the solid component concentration is particularly preferably in the range of 1 to 5% by mass, thereby setting the solution viscosity to the range of 3 to 15 mPa·s. The temperature for preparing the polymer composition is preferably 10 to 50°C, more preferably 20 to 30°C.

[0102] <Liquid Crystal Alignment Film / Liquid Crystal Display Element> The liquid crystal alignment film of the present invention is obtained from the above-described liquid crystal alignment agent. The liquid crystal alignment film of the present invention can be used for horizontally aligned or vertically aligned (VA type) liquid crystal alignment films, wherein the liquid crystal alignment film of the present invention is suitable for horizontally aligned liquid crystal display elements such as IPS or FFS types. Furthermore, the liquid crystal alignment film of the present invention is more preferably used for liquid crystal alignment films in photo-alignment processing methods. In addition, the liquid crystal alignment film of the present invention can be effectively applied to various technical applications, such as liquid crystal alignment films other than those described above (liquid crystal alignment films for phase difference films, liquid crystal alignment films for scanning antennas, liquid crystal array antennas, or liquid crystal alignment films for transmission and scattering type liquid crystal dimming elements), or it can also be applied to other applications, such as protective films (e.g., protective films for color filters), spacer films, interlayer insulating films, anti-reflective films, wiring coating films, anti-charge films, motor insulating films (gate insulating films for flexible displays), etc. The liquid crystal display element of the present invention includes the above-described liquid crystal alignment film. The liquid crystal display element of the present invention can be manufactured, for example, by a method including the following steps (1) to (3). The liquid crystal display element of the present invention can be manufactured, for example, by a method including the following steps (1) to (3) and (5) or steps (1) to (2) and (5). More preferably, it can be manufactured by a method including steps (1) to (5).

[0103] <Step (1): Step of applying liquid crystal alignment agent to substrate> Step (1) is the step of applying the liquid crystal alignment agent of the present invention to substrate. Specific examples of step (1) are described below.

[0104] For example, the liquid crystal alignment agent of the present invention is coated onto one side of a substrate having a patterned transparent conductive film using a suitable coating method such as a roller coater, spin coater, printing, or inkjet printer. Here, the substrate is not particularly limited as long as it is highly transparent; it can also be used in conjunction with glass substrates, silicon nitride substrates, or plastic substrates such as acrylic substrates or polycarbonate substrates. Furthermore, in reflective liquid crystal display elements, if the substrate is only on one side, an opaque material such as a silicon wafer can be used, and the electrodes can be made of light-reflecting materials such as aluminum. Moreover, in the manufacture of IPS or FFS type liquid crystal display elements, a substrate having electrodes composed of a patterned comb-shaped transparent conductive film or metal film and an opposing substrate without electrodes are used.

[0105] 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.

[0106] <Process (2): Process of firing the coated liquid crystal alignment agent> Process (2) is a process of firing the liquid crystal alignment agent coated on the substrate to form a film. Specific examples of process (2) are described below.

[0107] After the liquid crystal alignment agent is coated onto the substrate in step (1), the solvent can be evaporated by a heating unit such as a heating plate, a thermal cycling oven, or an IR (infrared) oven; or thermal imidization of polyamic acid or polyamic acid ester 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. For example, the firing temperature can be 40 to 180°C. From the viewpoint of shortening the process, it can be performed at 40 to 150°C. The firing time at this time is not particularly limited, and examples include 1 to 10 minutes or 1 to 5 minutes. In the case of thermal imidization of polyamic acid or polyamic acid ester, a firing step can be added after the step of removing the above-mentioned organic solvent, for example, in the temperature range of 150 to 300°C or 150 to 250°C. The firing time at this time is not particularly limited, and examples include 5 to 40 minutes or 5 to 30 minutes.

[0108] 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.

[0109] <Step (3): Alignment Process> Step (3) is a process of aligning the fired film (coating) obtained in step (2) as needed. That is, in horizontally aligned liquid crystal display elements such as IPS or FFS, the coating is subjected to an alignment capability imparting process. On the other hand, in vertically aligned liquid crystal display elements such as VA or PSA, the formed coating can be kept in this state and used as a liquid crystal alignment film, or the coating can be subjected to an alignment capability imparting process. As an alignment process for liquid crystal alignment films, brushing process and photo-alignment process can be listed, and photo-alignment process is more preferred. As a photo-alignment process, the following method can be listed: irradiating the surface of the above-mentioned film with radiation polarized in a certain direction, and, as needed, preferably performing a heating process at a temperature of 150 to 250°C to impart liquid crystal alignment (also called liquid crystal alignment capability). As radiation, ultraviolet light or visible light with a wavelength of 100 to 800 nm can be used. Among them, ultraviolet light with a wavelength of 100 to 400 nm is preferred, and ultraviolet light with a wavelength of 200 to 400 nm is more preferred.

[0110] The preferred radiation dose is 1–10,000 mJ / cm². 2 More preferably, it is 100–5000 mJ / cm². 2 More preferably, it is 100–1500 mJ / cm 2 The preferred value is 100–1000 mJ / cm³. 2 More preferably, it is 100–400 mJ / cm 2 When using conventional liquid crystal alignment agents, the light irradiation dose during the alignment process is 100–5000 mJ / cm². 2 However, in the liquid crystal alignment agent of the present invention, even if the amount of light irradiation during the alignment process is reduced, a liquid crystal alignment film that suppresses the deviation (non-uniformity) of liquid crystal alignment within the liquid crystal alignment film surface can be obtained.

[0111] Furthermore, to improve liquid crystal alignment when irradiated with radiation, the substrate having the aforementioned film can be irradiated while being heated at 50–250°C. The liquid crystal alignment film produced in this way allows liquid crystal molecules to be stably aligned in a specific direction.

[0112] Furthermore, in the above methods, water or solvents can be used to contact the liquid crystal alignment film irradiated with polarized radiation; or the liquid crystal alignment film irradiated with radiation can be heated.

[0113] The solvent used in the above-mentioned contact treatment is not particularly limited as long as it dissolves the decomposition products generated by the film-like material through 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, considering versatility and solvent safety, water, 2-propanol, 1-methoxy-2-propanol, or ethyl lactate are preferred. 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.

[0114] <Process (4): Process of heat treatment> Process (4) is a process of heat treatment of the liquid crystal alignment film that has undergone alignment treatment in process (3).

[0115] The irradiated film (coating) that has been irradiated with the above-mentioned radiation can also be subjected to heat treatment.

[0116] The preferred temperature for heat treatment of the coating irradiated with the above-mentioned radiation is 50–300°C, more preferably 120–250°C. The preferred heat treatment time is 1–30 minutes.

[0117] <Step (5): Step for manufacturing a liquid crystal cell> Prepare two substrates with liquid crystal alignment films formed as described above, and place liquid crystal between the two substrates that are placed opposite each other. Specifically, the following two methods can be listed.

[0118] In the first method, two substrates are first arranged opposite each other with their respective liquid crystal alignment films facing each other and separated by a gap (cell gap). Next, the two substrates are bonded together at the periphery using a sealant, and a liquid crystal composition is injected into the cell gap defined by the substrate surface and the sealant. After contact with the film surface, the injection hole is sealed.

[0119] In addition, a second method is known as the ODF (One Drop Fill) method. For example, a UV-curable sealant is applied to a predetermined area on one of the two substrates forming the liquid crystal alignment film, and then a liquid crystal composition is dropped onto several predetermined points on the surface of the alignment film. The other substrate is then bonded with the alignment film facing it, and the liquid crystal composition is spread across the entire surface of the substrate, contacting the film surface. Next, the entire surface of the substrate is irradiated with UV light to cure the sealant. Regardless of the method 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 alignment during liquid crystal filling.

[0120] It should be noted that when the coating is brushed, the two substrates are arranged at a predetermined angle to each other with the brushing direction of each coating, for example, in an orthogonal or antiparallel manner.

[0121] As a sealant, for example, epoxy resin containing a curing agent and alumina spheres as spacers can be used. There are no particular limitations on the liquid crystal composition described above; various liquid crystal compositions containing at least one liquid crystal compound (liquid crystal molecule) and having positive or negative dielectric anisotropy can be used. It should be noted that, hereinafter, liquid crystal compositions with positive dielectric anisotropy are referred to as positive liquid crystals, and liquid crystal compositions with negative dielectric anisotropy are referred to as negative liquid crystals. Examples of liquid crystal compositions include those exhibiting a nematic phase and those exhibiting a smectic phase, with nematic liquid crystal compositions being preferred.

[0122] The liquid crystal composition described above may contain liquid crystal compounds having fluorine, hydroxyl, amino, fluorine-containing groups (e.g., trifluoromethyl), cyano, alkyl, alkoxy, alkenyl, isothiocyanate, heterocyclic, cycloalkanes, cycloolefins, steroidal skeletons, benzene rings or naphthalene rings, or may contain compounds having two or more rigid sites (mesocrystalline skeletons) that exhibit liquid crystal properties (e.g., bimesocrystalline compounds formed by two rigid biphenyl or terphenyl structures linked by an alkyl group).

[0123] From the viewpoint of improving liquid crystal orientation, the above-mentioned liquid crystal composition may further contain additives. Such additives include: photopolymerizable monomers such as compounds with polymerizable groups; optically active compounds (e.g., S-811 manufactured by MERCK Co., Ltd.); antioxidants; ultraviolet absorbers; pigments; defoamers; polymerization initiators; or polymerization inhibitors, etc.

[0124] Examples of positive liquid crystal displays include: ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, and MLC-7081 manufactured by MERCK.

[0125] Examples of negative liquid crystals include MLC-6608, MLC-6609, MLC-6610, and MLC-7026-100 manufactured by MERCK.

[0126] In addition, MLC-3023 manufactured by MERCK is an example of a liquid crystal containing compounds with polymerizable groups.

[0127] Furthermore, a liquid crystal display element can be obtained by attaching a polarizing plate to the outer surface of the liquid crystal cell as needed. Examples of polarizing plates attached to the outer surface of the liquid crystal cell include: a polarizing plate made by sandwiching a polarizing film called an "H film" between a cellulose acetate protective film; or a polarizing plate composed of the H film itself, wherein the H film is formed by absorbing iodine while extending and oriented polyvinyl alcohol.

[0128] The IPS substrate, which is a comb-electrode substrate used in IPS (In-Plane Switching) mode, includes: a substrate; a plurality of linear electrodes formed on the substrate and configured in a comb-like shape; and a liquid crystal alignment film formed on the substrate in a manner that covers the linear electrodes.

[0129] It should be noted that the FFS substrate, which is used as a comb electrode substrate in the FFS (Frindge Field Switching) mode, has: a substrate; a surface electrode formed on the substrate; an insulating film formed on the surface electrode; a plurality of linear electrodes formed on the insulating film and configured in a comb shape; and a liquid crystal alignment film formed on the insulating film in a manner that covers the linear electrodes.

[0130] Figure 1 is a schematic cross-sectional view showing an example of a lateral electric field liquid crystal display element of the present invention, which is an example of an IPS mode liquid crystal display element.

[0131] In the lateral electric field liquid crystal display element 1 illustrated in FIG1, liquid crystal 3 is sandwiched between a comb-shaped electrode substrate 2 having a liquid crystal alignment film 2c and an opposing substrate 4 having a liquid crystal alignment film 4a. The comb-shaped electrode substrate 2 includes: a substrate 2a; a plurality of linear electrodes 2b formed on the substrate 2a and arranged in a comb-like pattern; and a liquid crystal alignment film 2c formed on the substrate 2a to cover the linear electrodes 2b. The opposing substrate 4 includes: a substrate 4b and a liquid crystal alignment film 4a formed on the substrate 4b. The liquid crystal alignment film 2c is, for example, the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4c is also, similarly, the liquid crystal alignment film of the present invention.

[0132] In this transverse electric field liquid crystal display element 1, when a voltage is applied to the linear electrode 2b, an electric field is generated between the linear electrodes 2b as shown by the electric field line L.

[0133] Figure 2 is a schematic cross-sectional view showing another example of the transverse electric field liquid crystal display element of the present invention, which is an example of an FFS mode liquid crystal display element.

[0134] In the lateral electric field liquid crystal display element 1 illustrated in Figure 2, liquid crystal 3 is sandwiched between a comb-shaped electrode substrate 2 having a liquid crystal alignment film 2h and a counter substrate 4 having a liquid crystal alignment film 4a. The comb-shaped electrode substrate 2 includes: a substrate 2d; a surface electrode 2e formed on the substrate 2d; an insulating film 2f formed on the surface electrode 2e; a plurality of linear electrodes 2g arranged in a comb-like pattern formed on the insulating film 2f; and a liquid crystal alignment film 2h formed on the insulating film 2f to cover the linear electrodes 2g. The counter substrate 4 includes: a substrate 4b and a liquid crystal alignment film 4a formed on the substrate 4b. The liquid crystal alignment film 2h is, for example, the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4a is also, similarly, the liquid crystal alignment film of the present invention.

[0135] In this transverse electric field liquid crystal display element 1, when a voltage is applied to the surface electrode 2e and the linear electrode 2g, an electric field is generated between the surface electrode 2e and the linear electrode 2g as shown by the electric field line L.

[0136] The following examples illustrate the invention in further detail, but are not intended to limit it. The abbreviations of the compounds used and the methods for determining their properties are described below. Furthermore, "Boc" represents tert-butoxycarbonyl.

[0137] (Specific diamine) WA-1 to WA-2: These are compounds represented by the formulas (WA-1) to (WA-2) below. (Other diamines) A1 to A8: These are compounds represented by the formulas (A1) to (A8) below. The compounds shown in formulas A4 and A5 were synthesized by the synthetic method described in WO2020 / 080477.

[0138] (Tetracarboxylic acid dianhydride) B1~B2: These are compounds represented by the formulas (B1)~(B2) below. (Additives) AD-1 to AD-2: These are compounds represented by the formulas (AD-1) to (AD-2) below. (Solvent) NMP: N-methyl-2-pyrrolidone.

[0139] BCS: Ethylene glycol monobutyl ether.

[0140] DMF: Dimethylformamide.

[0141] DMAc: Dimethylacetamide.

[0142] THF: Tetrahydrofuran.

[0143] (Viscosity determination) 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.

[0144] (Determination of molecular weight) The molecular weight of polyamic acid was determined using a room temperature gel permeation chromatography (GPC) apparatus (GPC-101) (manufactured by Showa Denko Corporation) and a chromatographic column (KD-803 and KD-805 in series) (manufactured by Showa Denko Corporation), as described below.

[0145] Column temperature: 50℃.

[0146] Eluent: N,N-dimethylformamide (as additives, lithium bromide monohydrate (LiBr·H2O) 30 mmol / L, phosphoric acid / anhydrous crystals (o-phosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 mL / L).

[0147] Flow rate: 1.0 ml / min.

[0148] 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 Laboratory).

[0149] <Synthesis of Specific Diamines (WA-1) to (WA-2)> The synthesis methods of specific diamines (WA-1) to (WA-2) are described in detail below. It should be noted that diamine (WA-2) is a novel compound not disclosed in the literature.

[0150] ( 1 (Measurement of H-NMR) Apparatus: Fourier transform superconducting nuclear magnetic resonance device (FT-NMR) "AVANCE III" (BRUKER) 500MHz.

[0151] Solvent: Deuterated dimethyl sulfoxide (DMSO-d6, standard substance: tetramethylsilane).

[0152] (Single Synthesis Example 1: Synthesis of (WA-1)) The diamine (WA-1) was synthesized according to the route shown below. In a 1 L four-necked flask, 6-bromo-2-naphthol (31.1 g, 140 mmol), potassium carbonate (38.7 g, 280 mmol), and potassium iodide (1.16 g, 7 mmol) were dissolved in DMF (249 g), and the mixture was heated to 100 °C and stirred. A mixture of 1,4-dichlorobutane (8.8 g, 70 mmol) dissolved in DMF (63 g) was slowly added, and the mixture was stirred for 15 hours. After confirming the completion of the reaction by HPLC, the mixture was cooled to room temperature, and pure water (620 g) was added, followed by stirring for 1 hour. The solid obtained after filtering the precipitated crystals with methanol was then dried under reduced pressure to obtain WA-1-1 (yield 28.7 g, 57.4 mmol, 82% yield, white solid).

[0153] 1 H-NMR (500MHz, DMSO-d6); δ (ppm) = 8.10 (2H, s), 7.83-7.75 (4H, m), 7.56-7. 54 (2H, m), 7.38 (2H, s), 7.23-7.22 (2H, m), 4.19 (4H, t), 1.99-1.95 (4H, m).

[0154] Add WA-1-1 (20.0 g, 40 mmol), benzophenone imine (15.9 g, 88 mmol), tris(dibenzylacetone)palladium (Pd2(dba)3) (0.7 g, 0.8 mmol), 2-dicyclohexylphosphine-2',4',6'-triisopropyl-1,1'-biphenyl (XPhos) (1.52 g, 3.2 mmol), sodium tert-butoxide (10.8 g, 112 mmol), and THF (400 g) to a 1 L four-necked flask. Heat to 70 °C and stir for 1 hour. Concentrate the reaction solution to 200 g, add pure water (200 g), and stir for 1 hour. Collect the precipitated crystals by vacuum filtration, transfer to a four-necked flask, dissolve in DMAc (256 g), slowly add trifluoroacetic acid (12.5 g, 110 mmol), and heat to 50 °C. After stirring for 30 minutes, the solution was allowed to return to room temperature, and N,N,N',N'-tetramethylethylenediamine (TMEDA) (16.9 g, 146 mmol) was added for neutralization. The reaction solution was concentrated to 128 g, and methanol (256 g) was added, followed by stirring for 1 hour. The solid obtained by filtering out the precipitated crystals was washed with methanol and then dried under reduced pressure to obtain WA-1 (yield 13.0 g, 34.9 mmol, 88% yield, light brown solid).

[0155] According to the following... 1 The H-NMR results confirmed that the solid was a diamine (WA-1).

[0156] 1 H-NMR (500MHz, DMSO-d6); δ (ppm) = 7.49-7.47 (2H, m), 7.44-7.42 (2H, m), 7.10 (2H, d), 6.99-6. 97 (2H, m), 6.90-6.88 (2H, m), 6.79 (2H, d), 5.08-5.06 (4H, m), 4.08 (4H, t), 1.96-1.92 (4H, m).

[0157] (Single Synthesis Example 2: Synthesis of (WA-2)) The diamine (WA-2) was synthesized according to the route shown below. In a 300 mL four-necked flask, 1,4-dichlorobutane (63.5 g, 500 mmol) was dissolved in DMF (86 g), and potassium carbonate (13.8 g, 100 mmol) was added. The mixture was heated to 100 °C and stirred. A mixture containing 4-bromo-4'-hydroxybiphenyl (12.4 g, 50 mmol) dissolved in DMF (38 g) was added, and the mixture was stirred for 2 hours. After confirming the reaction was complete by HPLC, the mixture was cooled to room temperature, and the precipitated salt was removed. The solution was concentrated to 64 g, and methanol (180 g) and pure water (180 g) were added. The mixture was stirred for 1 hour. The solid obtained by filtering the precipitated crystals with methanol was washed and dried under reduced pressure to obtain WA-2-1 (yield 14.6 g, 43.0 mmol, 86% yield, white solid).

[0158] 1 H-NMR (500MHz, DMSO-d6); δ (ppm) = 7.61-7.58 (6H, m), 7.02 (2H, d), 4.05 (2H, t), 3.72 (2H, t), 1.88-1.87 (4H, m).

[0159] To a 500 mL four-necked flask, add WA-2-1 (13.6 g, 40 mmol), 6-bromo-2-naphthol (8.9 g, 40 mmol), potassium carbonate (13.8 g, 100 mmol), and DMF (135 g), heat to 100 °C, and stir for 18 hours. After confirming the reaction was complete by HPLC, allow the solution to return to room temperature, add pure water (202 g), and stir for 1 hour. Wash the solid obtained by filtering the precipitated crystals with acetonitrile, and then dry under reduced pressure to obtain WA-2-2 (yield 19.5 g, 37.1 mmol, 93% yield, white solid).

[0160] 1H-NMR (500MHz, DMSO-d6); δ (ppm) = 8.11 (1H, m), 7.83-7.75 (2H, m), 7.61-7.55 (7H, m) , 7.37 (1H, m), 7.23 (1H, m), 7.04-7.03 (2H, m), 4.17-4.11 (4H, m), 1.04-1.03 (4H, m).

[0161] Add WA-2-2 (19.4 g, 37 mmol), benzophenone imine (14.7 g, 81 mmol), tris(dibenzylacetone)palladium (Pd2(dba)3) (0.6 g, 0.7 mmol), 2-dicyclohexylphosphine-2',4',6'-triisopropyl-1,1'-biphenyl (XPhos) (1.41 g, 2.9 mmol), sodium tert-butoxide (9.9 g, 103 mmol), and THF (389 g) to a 1 L four-necked flask. Heat to 70 °C and stir for 1 hour. Concentrate the reaction solution to 190 g, add pure water (200 g), and stir for 1 hour. Collect the precipitated crystals by vacuum filtration, transfer to a four-necked flask, dissolve in THF (537 g), slowly add trifluoroacetic acid (12.6 g, 111 mmol), and heat to 50 °C. After stirring for 30 minutes, the solution was allowed to return to room temperature, and N,N,N',N'-tetramethylethylenediamine (TMEDA) (17.2 g, 148 mmol) was added for neutralization. The reaction solution was concentrated to 260 g, and methanol (260 g) was added, followed by stirring for 1 hour. The solid obtained by filtering out the precipitated crystals was washed with methanol and then dried under reduced pressure to obtain WA-2 (yield 13.3 g, 33.4 mmol, 90% yield, light brown solid).

[0162] According to the following... 1 The H-NMR results confirmed that the solid was a diamine (WA-2).

[0163] 1 H-NMR (500MHz, DMSO-d6); δ (ppm) = 7.49-7.42 (4H, m), 7.28-7.27 (2H, m), 7.09 (1H, d), 6.99-6.88 ( 4H, m), 6.79 (1H, d), 6.622-6.60 (2H, m), 5.11-5.10 (4H, m), 4.07-4.05 (4H, m), 1.98-1.90 (4H, m).

[0164] <Polymer Synthesis> (Synthesis Example 1) A1 (0.973 g, 9.00 mmol), A2 (2.20 g, 9.00 mmol), WA-1 (2.23 g, 6.00 mmol), A7 (2.39 g, 6.00 mmol), B1 (6.39 g, 28.5 mmol), and NMP (104 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours, thereby obtaining a solution of polyamic acid (A-1) with a solid content concentration of 12% by mass (viscosity: 379 mPa·s). The number-average molecular weight (Mn) of this polyamic acid was 13242, and the weight-average molecular weight (Mw) was 34231.

[0165] (Synthesis Example 2) A1 (0.973 g, 9.00 mmol), A2 (2.20 g, 9.00 mmol), WA-2 (2.39 g, 6.00 mmol), A7 (2.39 g, 6.00 mmol), B1 (6.42 g, 28.7 mmol), and NMP (105 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a solution of polyamic acid (A-2) with a solid content of 12% by mass (viscosity: 398 mPa·s). The Mn of this polyamic acid was 12019, and the Mw was 33291.

[0166] (Synthesis Example 3) A1 (0.649 g, 6.00 mmol), A8 (4.78 g, 24.0 mmol), B2 (5.59 g, 28.5 mmol), and NMP (99.2 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at room temperature for 5 hours to obtain a solution of polyamic acid (B-1) with a solid content of 10% by mass (viscosity: 338 mPa·s). The Mn of this polyamic acid was 15932, and the Mw was 39013.

[0167] (Synthetic Example 4 (Comparative)) A1 (0.973 g, 9.00 mmol), A2 (2.20 g, 9.00 mmol), A3 (1.92 g, 6.00 mmol), A7 (2.39 g, 6.00 mmol), B1 (6.42 g, 28.7 mmol), and NMP (101 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a solution of polyamic acid (RA-1) with a solid content of 12% by mass (viscosity: 382 mPa·s). The Mn of this polyamic acid was 11912, and the Mw was 33413.

[0168] (Synthetic Example 5 (Comparative)) A1 (0.973 g, 9.00 mmol), A2 (2.20 g, 9.00 mmol), A4 (2.07 g, 6.00 mmol), A7 (2.39 g, 6.00 mmol), B1 (6.38 g, 28.4 mmol), and NMP (102 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a solution of polyamic acid (RA-2) with a solid content of 12% by mass (viscosity: 411 mPa·s). The Mn of this polyamic acid was 12018, and the Mw was 37021.

[0169] (Synthetic Example 6 (Comparative)) A1 (0.973 g, 9.00 mmol), A2 (2.20 g, 9.00 mmol), A5 (2.22 g, 6.00 mmol), A7 (2.39 g, 6.00 mmol), B1 (6.38 g, 28.4 mmol), and NMP (103 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a solution of polyamic acid (RA-3) with a solid content of 12% by mass (viscosity: 404 mPa·s). The Mn of this polyamic acid was 10383, and the Mw was 36113.

[0170] (Synthetic Example 7 (Comparative)) A1 (0.973 g, 9.00 mmol), A2 (2.20 g, 9.00 mmol), A6 (2.15 g, 6.00 mmol), A7 (2.39 g, 6.00 mmol), B1 (6.46 g, 28.8 mmol), and NMP (103 g) were added to a 100 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube. The mixture was stirred at 40 °C for 20 hours to obtain a solution of polyamic acid (RA-4) with a solid content of 12% by mass (viscosity: 401 mPa·s). The Mn of this polyamic acid was 10099, and the Mw was 36030.

[0171] Table 1 summarizes the types and amounts of diamine and tetracarboxylic acid components used in Synthetic Examples 1–7. In the table, the values ​​in parentheses indicate the amount (mole parts) of each monomer used relative to a total of 100 moles. <Preparation of liquid crystal alignment agent> (Example 1) NMP (9.33g) and BCS (4.00g) were added to the polyamic acid (A-1) solution (6.67g) obtained in Synthesis Example 1 and stirred at room temperature for 2 hours to obtain liquid crystal alignment agent (V-1).

[0172] (Example 2) The polyamic acid (A-1) solution (9.54g), NMP (3.78g), BCS (9.00g), a 10% NMP dilution of AD-1 (0.800g), and a 1% NMP dilution of AD-2 (1.59g) obtained in Synthesis Example 3 were added to the polyamic acid (B-1) solution (5.30g) obtained in Synthesis Example 1. The mixture was stirred at room temperature for 2 hours to obtain liquid crystal alignment agent (V-2).

[0173] (Example 3) The solution of polyamic acid used was changed from solution (A-1) to solution (A-2), and the same procedure as in Example 2 was followed, thereby obtaining liquid crystal alignment agent (V-3).

[0174] (Comparative Examples 1) to (Comparative Examples 4) changed the polyamic acid solution used from solution (A-1) to solutions (RA-1) to (RA-4), otherwise operated in the same manner as in Example 1, thereby obtaining liquid crystal alignment agents (RV-1) to (RV-4).

[0175] (Comparative Examples 5) to (Comparative Examples 6) changed the polyamic acid solution used from solution (A-1) to solutions (RA-2) to (RA-3), and operated in the same manner as in Example 2, thereby obtaining liquid crystal alignment agents (RV-5) to (RV-6).

[0176] The specifications of the liquid crystal alignment agents obtained in Examples 1-3 and Comparative Examples 1-6 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. 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.

[0177] <Construction of FFS-driven liquid crystal cell> A liquid crystal cell with an FFS mode liquid crystal display element is manufactured.

[0178] First, a substrate with electrodes was prepared. The substrate was a rectangular glass plate with a thickness of 0.7 mm and a diameter of 30 mm × 50 mm. On the substrate, an ITO electrode with a dense pattern constituting the counter electrode was formed as the first layer. On the counter electrode of the first layer, a SiN (silicon nitride) film formed by CVD (chemical vapor deposition) was formed as the second layer. The SiN film of the second layer had a thickness of 500 nm and functioned as an interlayer insulating film. On the SiN film of the second layer, a comb-shaped pixel electrode formed by patterning the ITO film was disposed as the third layer, forming two types of pixels: a first pixel and a second pixel. Each pixel had dimensions of 10 mm in length and 5 mm in width. At this point, the counter electrode of the first layer and the pixel electrode of the third layer were electrically insulated by the SiN film of the second layer.

[0179] The pixel electrode of the third layer has a comb-like shape in which multiple central portions are arranged in parallel with a width of 3μm and an inner angle of 160°, and are separated by a 6μm interval. A pixel has a first region and a second region bounded by the line connecting the curved portions of the multiple electrode elements.

[0180] Next, the liquid crystal alignment agents (V-1) to (V-3) and (RV-1) to (RV-6) obtained in Examples 1 to 3 and Comparative Examples 1 to 6 were filtered using a filter with a pore size of 1.0 μm. These agents were then spin-coated onto the prepared electrode substrate (first glass substrate) and a glass substrate with an ITO film on its back side and columnar spacers with a height of 4 μm (second glass substrate). After drying on a heating plate at 80°C for 2 minutes, the coating was fired in a hot air circulating oven at 230°C for 30 minutes to form a coating film with a thickness of 100 nm. The coating surface was then irradiated with linearly polarized ultraviolet light of 254 nm with extinction ratio of 26:1, as shown in Table 3, through a polarizing plate to perform alignment treatment, thereby obtaining a substrate with a liquid crystal alignment film. It should be noted that, regarding the liquid crystal alignment film formed on the aforementioned substrate with electrodes, the alignment process is 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 second glass substrate, the alignment process is performed such that the alignment direction of the liquid crystal on the first glass substrate is consistent with the alignment direction of the liquid crystal on the second glass substrate when the liquid crystal cell is manufactured. Using the two substrates as a group, a sealant (Mitsui Chemicals XN-1500T) is printed on the substrate, and the other substrate is bonded with the liquid crystal alignment film surfaces facing each other and the alignment direction at 0°. Then, a heat treatment at 150°C for 60 minutes is performed to cure the sealant, producing an empty cell. Liquid crystal MLC-3019 (MERCK) is injected into this empty cell using a reduced-pressure injection method, and the injection port is sealed to obtain an FFS-driven liquid crystal cell. Then, the obtained liquid crystal cell is heated at 120°C for 1 hour and left to stand overnight for evaluation.

[0181] <Evaluation of In-Plane Uniformity of Contrast Ratio> The AxoStep sensor manufactured by AXOMETRICS was used to evaluate the non-uniformity of the torsion angle of the liquid crystal cell. The liquid crystal cell fabricated above was placed on a measuring stage, and the distribution of Circular Retardance within the pixel plane was measured without applying voltage. Three times the standard deviation σ was calculated, i.e., 3σ. It can be said that the smaller the value of 3σ, the better the in-plane uniformity. As an evaluation benchmark, a value less than 1.00 was defined as "Excellent," a value between 1.00 and 1.10 as "Good," and a value greater than 1.10 as "Poor."

[0182] 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.

[0183] <Evaluation of the stability of liquid crystal alignment> This evaluation assesses the image retention (also known as AC image retention) caused by the deterioration of the alignment performance of the liquid crystal alignment film during long-term AC driving.

[0184] The FFS-driven liquid crystal cell fabricated above was subjected to an AC voltage of ±4V at a frequency of 60Hz for 120 hours under a constant temperature environment of 60°C. Then, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited and left at room temperature 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 and the liquid crystal in the second region of the pixel was calculated in the form of angles, in the state without applied voltage. 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. As an evaluation criterion, a value less than 0.05° was defined as "excellent," a value between 0.05° and 0.10° was defined as "good," and a value greater than 0.10° was defined as "poor."

[0185] 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. As shown in Table 3, the liquid crystal alignment film obtained using a liquid crystal alignment agent with specific diamines WA-1 to WA-2 exhibits higher in-plane uniformity with less light irradiation compared to the liquid crystal alignment film obtained using a liquid crystal alignment agent composed of a diamine component without specific diamines. Furthermore, it demonstrates liquid crystal alignment stability equal to or higher than that of conventional liquid crystal alignment films.

[0186] The liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention can be suitably used in liquid crystal display elements. Furthermore, these elements are useful in liquid crystal displays for display purposes, and also in dimming windows, optical shutters, etc., for controlling light transmission and blocking.

[0187] Industrial Applicability: By using the liquid crystal alignment agent of the present invention, the unevenness (non-uniformity) of the twist angle of the liquid crystal within the liquid crystal alignment film surface is small, which expands the range of light irradiation amounts used to obtain the liquid crystal alignment film, and efficiently obtains a high-quality liquid crystal alignment film. Therefore, its application in liquid crystal display elements requiring high display quality is expected. Furthermore, these elements are useful in liquid crystal displays for display purposes, and also in dimming windows, optical shutters, etc., for controlling light transmission and blocking.

[0188] Explanation of reference numerals in the attached figures: 1: Lateral electric field liquid crystal display element; 2: Comb electrode substrate; 2a: Substrate; 2b: Linear electrode; 2c: Liquid crystal alignment film; 2d: Substrate; 2e: Surface electrode; 2f: Insulating film; 2g: Linear electrode; 2h: Liquid crystal alignment film; 3: Liquid crystal; 4: Opposite substrate; 4a: Liquid crystal alignment film; 4b: Substrate; L: Electric field line.

Claims

1. A polymer, which is polymer (A), wherein polymer (A) is at least one selected from the group consisting of a polyimide precursor having a repeating unit (a1) as shown in formula (1) and a polyimide as an imide derivative of the polyimide precursor. In formula (1), X1 represents a tetravalent organic group; Y1 is a divalent organic group with three or more benzene rings as shown in formula (H); R and Z each independently represent a hydrogen atom or a monovalent organic group. In equation (H), L1 and L 1’ Each can independently represent a single bond, -O-, -S-, -C(=O)-, -O-C(=O)-, or -C(=O)-NR-, where -C(=O)-NR-, R represents a hydrogen atom or a monovalent organic group, A represents an alkylene group with 4 to 10 carbon atoms, and Ar1 and Ar 1’ Each independently represents a benzene ring, biphenyl structure, or naphthalene ring; Ar1 ​​and Ar 1’ Any hydrogen atom on the ring may be optionally replaced by a monovalent group; * indicates a bond.

2. The polymer according to claim 1, wherein, The group "*-L1-A-L" in formula (H) 1’ -*” represents the group "*-(CH2) n -*”, group "*-O-(CH2) n -O-*”, group "*-C(=O)-(CH2) n -C(=O)-*”, group "*-C(=O)-NR-(CH2) n -O-*”, group "*-O-C(=O)-(CH2) n -O-*”, group "*-O-C(=O)-(CH2) n -O-C(=O)-*”, group "*-O-C(=O)-(CH2) n -C(=O)-O-*”, group "*-S-(CH2) n -S-*”, group "*-C(=O)-NR-(CH2) n -NR-C(=O)-*”, group "*-C(=O)-O-(CH2) n -O-C (=O)-*”, group "*-O-(CH2) n -*”, group "*-S-(CH2) n -*” or group "*-NR-C(=O)-(CH2) n The group "-C(=O)-NR-*" represents a hydrogen atom or a monovalent organic group, where R represents a hydrogen atom or a monovalent organic group, n is an integer from 4 to 10, and * represents a bond. 1’ In the "-*", * represents a bond.

3. The polymer according to claim 1 or 2, wherein, In formula (1), Y1 is any divalent organic group represented by any of the following formulas (h-1), (h-2), and (h-4). In equations (h-1), (h-2), and (h-4), R a1 R a2 and R a4 The symbol represents a monovalent organic group; L represents the group "*-L1-A-L" in the formula (H). 1’ "-*", where * represents a bond; m are independent integers from 0 to 6, and n are independent integers from 0 to 4; in the presence of multiple R a1 R a2 and R a4 In the case of [missing information], each can be either the same or different; * indicates a bond.

4. The polymer according to claim 1 or 2, wherein, In formula (1), Y1 is derived from the compounds shown in formulas (WA-1) to (WA-2) below. 。 5. The polymer according to any one of claims 1 to 4, wherein, The polymer (A) is at least one polymer selected from the group consisting of a polyimide precursor having a repeating unit (a2) as shown in formula (2) below and a polyimide as an imide derivative of the polyimide precursor. In formula (2), X2 represents a tetravalent organic group; Y2 represents a divalent organic group as shown in formulas (o-1) to (o-14); R and Z each have the same meaning as R and Z in formula (1). In formulas (o-1) to (o-14), * represents a bond; in formulas (o-13) to (o-14), the two m are independent; any hydrogen atom on the ring of the benzene ring, biphenyl structure or naphthalene ring in formulas (o-1) to (o-14) may be substituted with a monovalent group.

6. The polymer according to any one of claims 1 to 5, wherein, The polymer (A) is at least one polymer selected from the group consisting of a polyimide precursor and a polyimide as an imide derivative of the polyimide precursor, wherein the polyimide precursor further comprises at least one selected from the group consisting of a repeating unit (a2') shown in formula (2') and a repeating unit (a3) ​​shown in formula (3). In equations (2') and (3), X 2’ X3 represents a tetravalent organic group, Y 2’ Y2 represents the divalent organic group shown in the following formula (O2), Y3 represents a divalent organic group with 6 to 30 carbon atoms having the group "-N(D)-" in the molecule; R and Z each have the same meaning as R and Z in the above formula (1), and in the group "-N(D)-", D represents a carbamate protecting group. In equation (O2), m represents an integer from 0 to 2; when m is 0, Ar 2’ Indicating a benzene ring or naphthalene ring, when m is 1 to 2, Ar 2’ Each independently represents a benzene ring; Ar 2’ Any hydrogen atom on the ring may be optionally replaced by a monovalent group; Q 2’ Indicates a single bond or -O-; * indicates a bonded bond; in the presence of multiple Ar... 2’ and Q 2’ In the case of [these conditions], each may choose to be the same or different.

7. The polymer according to any one of claims 1 to 6, wherein, X1 is a tetravalent organic group derived from acyclic aliphatic tetracarboxylic dianhydride or its derivatives, alicyclic tetracarboxylic dianhydride or its derivatives, or aromatic tetracarboxylic dianhydride or its derivatives, and derived from a tetracarboxylic dianhydride or its derivatives having at least one partial structure selected from the group consisting of cyclobutane ring structure, cyclopentane ring structure and cyclohexane ring structure.

8. The polymer according to any one of claims 1 to 7, wherein, The polymer (A) comprises the repeating unit (a1) and the imidized structure of the repeating unit (a1) in an amount of 5 to 100 mol% of all repeating units.

9. The polymer according to any one of claims 1 to 8, wherein, The polymer (A) comprises the repeating unit (a1) and the imidized structure of the repeating unit (a1) in such a manner that the total percentage is more than 5 mol% and less than 95 mol% of all repeating units.

10. The polymer according to any one of claims 5 and 7 to 9, wherein, The polymer (A) comprises repeating units (a1) and (a2) and their imidized structures in an amount totaling more than 10 mol% of all repeating units.

11. A compound represented by the following formulas (WA-1) to (WA-2), 。

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