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

Abstract

Provided are: a liquid crystal alignment agent from which a liquid crystal alignment film having a high voltage holding ratio even after prolonged exposure under high-temperature and high-humidity conditions, and having excellent residual image characteristics due to rapid relaxation of accumulated charges can be obtained; a liquid crystal alignment film obtained from the liquid crystal alignment agent; and a liquid crystal display element using the same. Furthermore, provided are: a liquid crystal alignment agent from which a liquid crystal alignment film having high light transmittance can be obtained; a liquid crystal alignment film obtained from the liquid crystal alignment agent; and a liquid crystal display element using the same.　The liquid crystal alignment agent contains a polymer component having: a first repeating unit (a1) selected from the group consisting of a repeating unit represented by formula (1-a) and a repeating unit represented by formula (1-i); and a second repeating unit (a2) selected from the group consisting of a repeating unit represented by formula (2-a) and a repeating unit represented by formula (2-i). (The meaning of each substituent is as described in the specification.)

Description

[Technical field]

[0001] The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film obtained from the liquid crystal aligning agent, and a liquid crystal display device having the liquid crystal alignment film. [Background technology]

[0002] Conventionally, various driving methods have been developed for liquid crystal display elements, which differ in electrode structure and physical properties of liquid crystal molecules used, and various display elements such as TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, VA (Vertical Alignment) type, IPS (In Plane Switching) type, and FFS (Fringe Field Switching) type are known. These liquid crystal display elements have a liquid crystal alignment film for aligning the liquid crystal molecules. Known materials for the liquid crystal alignment film include, for example, polyamic acid, polyamic acid ester, polyimide, and polyamide. In VA-type liquid crystal display elements, which are one of the driving methods for liquid crystal display elements, a technology is known in which a photopolymerizable compound is added to the liquid crystal composition in advance, a vertical alignment film such as a polyimide film is used, and ultraviolet light is irradiated while a voltage is applied to the liquid crystal cell, thereby increasing the response speed of the liquid crystal (PSA (Polymer Sustained Alignment) type element) (see, for example, Patent Document 1 and Non-Patent Document 1).

[0003] On the other hand, in this type of liquid crystal display element, if static electricity accumulates in the liquid crystal cell, or if charge accumulates in the liquid crystal cell due to the application of positive and negative asymmetric voltages generated by driving, these accumulated charges affect the display as disturbances in the liquid crystal alignment and residual images, significantly reducing the display quality of the liquid crystal element. Patent Document 2 proposes a polyimide-based liquid crystal alignment film having a pyrrole structure as a liquid crystal alignment film that solves these problems. In recent years, large-screen, high-definition liquid crystal televisions have been widely used, and liquid crystal display elements for such applications are required to have stricter requirements for image retention than display applications that mainly display characters and still images, and are also required to have characteristics that can withstand long-term use in harsh environments. Therefore, the liquid crystal alignment film used therein is required to be more reliable than before, and the electrical characteristics of the liquid crystal alignment film are required to not only have good initial characteristics, but also to maintain good characteristics even after long-term exposure to high temperature and high humidity, for example. As a liquid crystal alignment film that solves such problems, Patent Document 3 proposes a polyimide-based liquid crystal alignment film having a diphenylamine structure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2003-307720 [Patent Document 2] International Publication No. 2019 / 013339 [Patent Document 3] International Publication No. 2009 / 093709 [Non-patent literature]

[0005] [Non-Patent Document 1] K.Hanaoka,SID 04 DIGEST, P1200-1202 Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, in ultra-high definition liquid crystal display elements such as 4K or 8K, the occupancy rate of the black matrix (BM) and TFT increases, reducing the aperture ratio of the panel, so improving the transmittance of the display area is considered important.

[0007] In view of the above circumstances, the object of the present invention is to provide a liquid crystal aligning agent capable of obtaining a liquid crystal alignment film which has a high voltage retention rate even after long-term exposure to high temperature and high humidity, and which quickly relaxes accumulated charges and has excellent afterimage characteristics, a liquid crystal alignment film obtained from the liquid crystal aligning agent, and a liquid crystal display element using the same. Further, the present invention aims to provide a liquid crystal aligning agent capable of obtaining a liquid crystal alignment film having high light transmittance, a liquid crystal alignment film obtained from the liquid crystal aligning agent, and a liquid crystal display element using the same. [Means for solving the problem]

[0008] Means for Solving the Problems The present inventors have conducted intensive research to achieve the above object, and as a result have found that a liquid crystal aligning agent containing a specific component is effective in achieving the above object, thereby completing the present invention.

[0009] The present invention is based on these findings and has the following gist. A first repeating unit (a1) selected from the group consisting of a repeating unit represented by the following formula (1-a) and a repeating unit represented by the following formula (1-i), A liquid crystal aligning agent comprising a polymer component having a repeating unit represented by the following formula (2-a) and a second repeating unit (a2) selected from the group consisting of repeating units represented by the following formula (2-i): [ka] [ka] (X1 and X2 each represent a tetravalent organic group. Y1 represents a divalent organic group having any of the structures represented by the following formulae (S1) to (S3). Y2 represents a divalent organic group represented by the following formula (2c). Two R1s and R2 each independently represent a hydrogen atom or a monovalent organic group. Two Z1s and Z2 each independently represent a hydrogen atom or a monovalent organic group.) [ka] (X 1 and X2 are each independently a single bond, -(CH2) a -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -COO-, -OCO- or -((CH2) a1 -A1) m1 In this, a1 is an integer of 1 to 15, A1 is -O- or -COO-, and m1 is an integer of 1 to 2. 1 and G 2 Each independently represents a divalent cyclic group selected from the group consisting of a divalent aromatic group having 6 to 12 carbon atoms and a divalent alicyclic group having 3 to 8 carbon atoms. Any hydrogen atom on the cyclic group may be substituted. Each of m and n independently represents an integer of 0 to 3, and m+n is 1 to 6, preferably 1 to 4. R 1 represents 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; R 1 Any hydrogen atom forming X may be substituted with a fluorine atom. 1 , X 2 , G 1 , G 2 If a1, m1 and A1 exist multiple times, then there are multiple X 1 , X 2 , G 1 , G 2 , a1, m1 and A1 each independently have the above definition. [ka] (X 3 represents a single bond, -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -CHO-, -COO- or -OCO-. 2 represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms; R 2 Any hydrogen atom forming the formula (I) may be substituted with a fluorine atom. [ka] (X 4represents -CONH-, -NHCO-, -O-, -CHO-, -COO- or -OCO-. 3 represents a structure having a steroid skeleton.) [ka] (R represents a hydrogen atom or a monovalent organic group. * represents a bond.)

[0010] In this specification, * represents a bond in all cases. Boc represents a tert-butoxycarbonyl group. Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms. Examples of carbamate-based protecting groups include tert-butoxycarbonyl groups and 9-fluorenylmethoxycarbonyl groups. Effect of the Invention

[0011] According to the liquid crystal aligning agent of the present invention, it is possible to obtain a liquid crystal alignment film which has a high voltage retention rate even after long-term exposure to high temperature and high humidity, and which quickly relaxes accumulated charges and has excellent afterimage characteristics. Furthermore, the liquid crystal aligning agent of the present invention can provide a liquid crystal alignment film having high light transmittance. The mechanism by which the above-mentioned effects of the present invention are obtained is not necessarily clear, but the following is considered to be one of the reasons. That is, by using a liquid crystal alignment agent containing the above-mentioned polymer, hydrolysis of the polymer is unlikely to occur even under high temperature and high humidity conditions, so it is considered that a liquid crystal alignment film with a high voltage retention rate can be obtained. In addition, when the absorbance in the visible region was measured using an oxidized form of the polymer, which is one of the factors that reduces light transmittance, as a model compound, the absorbance of the oxidized form of the above-mentioned polymer was extremely small, so it is considered that a liquid crystal alignment film with high light transmittance can be obtained. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, each component contained in the liquid crystal aligning agent of the present disclosure and other components that are optionally blended as necessary will be described. <Polymer component> The liquid crystal aligning agent of the present invention comprises a first repeating unit (a1) selected from the group consisting of a repeating unit represented by the above formula (1-a) and a repeating unit represented by the above formula (1-i), It contains a polymer component having a repeating unit represented by the above formula (2-a) and a second repeating unit (a2) selected from the group consisting of repeating units represented by the above formula (2-i).

[0013] Specific examples of the polymer component include (i) at least one polymer (P-a1+a2) selected from the group consisting of polyimide precursors having the first repeating unit (a1) and the second repeating unit (a2) in the same molecule and imidized polymers thereof (hereinafter also referred to as copolymers), and (ii) a mixture (hereinafter also referred to as polymer blends) of at least one polymer (P-a1) selected from the group consisting of polyimide precursors having the first repeating unit (a1) and imidized polymers thereof and at least one polymer (P-a2) selected from the group consisting of polyimide precursors having the second repeating unit (a2) and imidized polymers thereof. The copolymers or polymer blends may be used alone or in combination. The polymer component may further contain at least one polymer selected from the group consisting of polyimide precursors and imidized polymers thereof, which do not have either the first repeating unit (a1) or the second repeating unit (a2).

[0014] When the polymer component is the copolymer, the total of the first repeating unit (a1) and the second repeating unit (a2) is preferably 5 to 100 mol %, more preferably 10 to 100 mol %, of all repeating units constituting the copolymer. The content of the repeating unit (a1) is preferably from 1 to 90 mol %, and more preferably from 1 to 85 mol %, of all the repeating units constituting the copolymer.

[0015] When the polymer component is the polymer blend, the content of the repeating unit (a1) is, in terms of enhancing liquid crystal alignment, preferably from 1 mol % to 99 mol %, more preferably from 2 mol % to 95 mol %, and even more preferably from 5 mol % to 90 mol %, of the total repeating units constituting the polymer (P-a1). In addition, from the viewpoint of efficiently obtaining the effects of the present invention, the content of the repeating unit (a2) is preferably from 5 mol % to 90 mol % of all the repeating units constituting the polymer (P-a2), and more preferably from 10 mol % to 80 mol %.

[0016] The mass ratio of the content of the polymer (P-a2) to the content of the polymer (P-a1) is preferably from 5 / 95 to 95 / 5, and more preferably from 10 / 90 to 90 / 10.

[0017] (First repeating unit (a1)) In the above formula (1-a) and formula (1-i), Y1 represents a divalent organic group having a structure represented by the above formulas (S1) to (S3). Y1 is preferably a divalent organic group derived from a diamine having a structure represented by the above formulas (S1) to (S3). Specific examples of the divalent organic group having the structure represented by the above formulae (S1) to (S3) include divalent organic groups derived from aromatic diamine (d) having the structure represented by the above formulae (S1) to (S3) in its side chain. The divalent organic group having the structure represented by the above formulae (S1) to (S3) is preferably a group obtained by removing two amino groups from the aromatic diamine (d).

[0018] G in the above formula (S1) 1 and G 2In the above, examples of the substituent on the cyclic group include substituents selected from the group consisting of halogen atoms, halogen atom-containing alkyl groups, halogen atom-containing alkoxy groups, alkyl groups having 1 to 10 carbon atoms, alkoxy groups having 1 to 10 carbon atoms, alkenyl groups having 1 to 10 carbon atoms, and heteroatom-containing groups in which a carbon-carbon bond in any methylene group of the halogen atom-containing alkyl groups, halogen atom-containing alkoxy groups, alkyl groups, alkoxy groups, and alkenyl groups is interrupted by an oxygen atom. Preferred specific examples of the structure represented by formula (S1) include structures represented by formulas (S1-1) to (S1-7) below. Preferred specific examples of the structure represented by formula (S3) include a structure represented by formula (S3-a). In formula (S3-a), X represents formula (X1), formula (X2), or -CH2O-, Col represents formula (Col-1), formula (Col-2), or formula (Col-3), and G represents formula (G1), formula (G2), formula (G3), or formula (G4). [ka]

[0019] In the above formula, R 1 represents 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. p is -(CH2) a A1 represents an oxygen atom or -COO-* (wherein the bond marked with "*" is (CH2)), -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -CHO-, -CH2-OCO-, -COO-, or -OCO-). a2 A2 is an oxygen atom or *-COO- (where the bond marked with "*" is (CH2) a2 each of a1 and a3 independently represents an integer of 0 or 1, a2 represents an integer of 1 to 10, and Cy represents a 1,4-cyclohexylene group or a 1,4-phenylene group. [ka]

[0020] In the above formula (S2), X 3 is preferably -CONH-, -NHCO-, -O-, -CHO-, -COO- or -OCO- from the viewpoint of enhancing liquid crystal alignment properties. R 2 From the viewpoint of liquid crystal alignment, R is preferably an alkyl group having 3 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms. 2 Any hydrogen atom forming the formula (I) may be substituted with a fluorine atom.

[0021] The aromatic diamine (d) preferably has at least one benzene ring. Specific examples of the aromatic diamine (d) include diamines represented by the following formula (d1) or formula (d2). [ka] (X is a single bond, -O-, -C(CH3)2-, -NH-, -CO-, -(CH2) m -, -SO2-, -O-(CH2) m -O-, -OC(CH3)2-, -CO-(CH2) m -, -NH-(CH2) m -, -SO2-(CH2) m -, -CONH-(CH2) m -, -CONH-(CH2) m -NHCO- or -COO-(CH2) m represents a divalent organic group of -OCO-. m is an integer of 1 to 8. Y represents any of the structures of the above formulae (S1) to (S3). In the above formula (d2), the two Y's may be the same or different.

[0022] Preferred examples of the diamine represented by the above formula (d1) include the following formulas (d1-1) to (d1-7): Preferred examples of the diamine represented by the above formula (d2) include the following formulas (d2-1) to (d2-6): [ka] [ka] (X v1 ~X v4 , X p1 ~X p8 are each independently -(CH2) a -(a is an integer of 1 to 15), -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -CHO-, -CH2-OCO-, -COO-, or -OCO-; X V5 ~X V6 , X s1 ~X s4 Each independently represents -O-, -CH2O-, -COO- or -OCO-. X v7 represents a single bond, -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -CHO-, -COO- or -OCO-. X a ~X f is a single bond, -O-, -NH-, or -O-(CH2) m -O- (m represents an integer of 1 to 8), R v1 ~R v4 , R 1a ~R 1h are each independently: -C n H 2n+1 (n represents an integer of 1 to 20), or -OC n H 2n+1 (n represents an integer from 2 to 20.)

[0023] In the above formula (1-a) and formula (1-i), X1 represents a tetravalent organic group. X1 preferably represents a tetravalent organic group derived from a tetracarboxylic dianhydride or a derivative thereof. The tetravalent organic group may be a tetravalent organic group derived from an acyclic aliphatic tetracarboxylic dianhydride or a derivative thereof, a tetravalent organic group derived from an alicyclic tetracarboxylic dianhydride or a derivative thereof, or a tetravalent organic group derived from an aromatic tetracarboxylic dianhydride or a derivative thereof, and is preferably a tetravalent organic group derived from a tetracarboxylic dianhydride or a derivative thereof represented by the following formula (3). [ka] (X represents a structure selected from any one of the following formulas (x-1) to (x-13).) [ka] (R 1 ~R 4 R each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group. 5 and R 6 Each of A1 and A2 independently represents a hydrogen atom or a methyl group. Each of j and k is an integer of 0 or 1, and each of A1 and A2 independently represents a single bond, -O-, -CO-, -COO-, phenylene, a sulfonyl group, or an amide group. *1 is a bond bonded to one acid anhydride group, and *2 is a bond bonded to the other acid anhydride group. In the above formula (x-13), the two A2 may be the same or different from each other.)

[0024] More preferred specific examples of the above formula (x-1) include the following formulae (X1-1) to (X1-6).

[0025] [ka]

[0026] Preferred specific examples of the above formulae (x-12) and (x-13) include the following formulae (x-14) to (x-29). [ka] [ka]

[0027] Preferred examples of the tetracarboxylic dianhydride represented by the above formula (3) or a derivative thereof include tetracarboxylic dianhydrides represented by the formula (3) in which X is any of the above formulae (x-1) to (x-7) and (x-11) to (x-13) or a derivative thereof.

[0028] In the above formula (1-a), two R1 each independently represents a hydrogen atom or a monovalent organic group. Examples of the monovalent organic group include a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Two R1 each independently preferably represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. In the above formula (1-a), two Z1 each independently represents a hydrogen atom or a monovalent organic group. Examples of the monovalent organic group include a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, an alkenyl group having 2 to 10 carbon atoms which may have a substituent, an alkynyl group having 2 to 10 carbon atoms which may have a substituent, a tert-butoxycarbonyl group, or a 9-fluorenylmethoxycarbonyl group. Examples of the substituent include a halogen atom, a hydroxyl group, a carboxyl group, an amino group, and a nitrile group. Two Z1 each independently preferably represent a hydrogen atom or a methyl group. In the above formula (1-a) and formula (1-i), each of X1, Y1, R1, and Z1 may be one type or two or more types.

[0029] (Second repeating unit (a2)) In the above formula (2-a) and formula (2-i), Y2 represents a divalent organic group represented by the following formula (2c).

[0030] [ka] (R represents a hydrogen atom or a monovalent organic group.)

[0031] Examples of the monovalent organic group for R in the above formula (2c) include an alkyl group, an alkoxyalkyl group, and a phenyl group having 1 to 12 carbon atoms. Examples of the alkyl group having 1 to 12 carbon atoms include a methyl group, an ethyl group, and a propyl group.

[0032] In the above formula (2c), R is preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxyalkyl group, or a phenyl group, from the viewpoint of suitably achieving the effects of the present invention.

[0033] More preferred examples of Y2 include groups in which two amino groups have been removed from carbazole selected from the group consisting of 3,6-diaminocarbazole, 9-methyl-3,6-diaminocarbazole, 9-ethyl-3,6-diaminocarbazole, and 9-phenyl-3,6-diaminocarbazole.

[0034] X2 in the above formula (2-a) and formula (2-i) may be the same as X1 in the above formula (1-a) and formula (1-i). Examples of R2 in the above formula (2-a) include the same as R1 in the above formula (1-a). Z2 in the above formula (2-a) may be the same as Z1 in the above formula (1-a). In the above formula (2-a) and formula (2-i), each of X2, Y2, R2, and Z2 may be one type or two or more types.

[0035] (Third repeat unit) The polymer component may further include a third repeating unit (a3) ​​selected from the group consisting of a repeating unit represented by the following formula (3-a) and a repeating unit represented by the following formula (3-i). [ka] (X3 represents a tetravalent organic group. Y3 represents a divalent organic group, and represents a divalent organic group other than the divalent organic group having the structure represented by the above formulas (S1) to (S3) and the divalent organic group represented by the above formula (2c). Two R3s and two Z3s have the same meanings as R1 and Z1 in formula (1-a), respectively.)

[0036] Specific embodiments of the polymer component further having the third repeating unit (a3) ​​include copolymers and polymer blends. An example of the copolymer is at least one polymer selected from the group consisting of a polyimide precursor having the first repeating unit (a1), the second repeating unit (a2), and the third repeating unit (a3) ​​in the same molecule, and an imidized polymer thereof. Examples of the polymer blend include a mixture of at least one polymer (P-a1+a2) selected from the group consisting of polyimide precursors having the first repeating unit (a1) and the second repeating unit (a2) in the same molecule and imidized polymers thereof, and at least one polymer (P-a1+a3) selected from the group consisting of polyimide precursors having the first repeating unit (a1) and the third repeating unit (a3) ​​in the same molecule and imidized polymers thereof. The polymer (P-a1+a3) may not have the second repeating unit (a2). The copolymer or polymer blend may be used alone or in combination.

[0037] When the polymer component is the above copolymer, the content of the repeating unit (a3) ​​is preferably from 5 to 90 mol %, more preferably from 10 to 80 mol %, of all the repeating units constituting the above copolymer. In this case, the total amount of the first repeating unit (a1) and the second repeating unit (a2) is preferably 10 to 95 mol %, more preferably 20 to 90 mol %, of all the repeating units constituting the copolymer.

[0038] When the polymer component is the above-mentioned polymer blend, the mass ratio of the content of the above-mentioned polymer (P-a1+a3) to the content of the above-mentioned polymer (P-a1+a2) is preferably 5 / 95 to 95 / 5, and more preferably 10 / 90 to 90 / 10.

[0039] Y3 preferably represents a divalent organic group derived from a diamine. Specific examples of the divalent organic group of Y3 include p-phenylenediamine, m-phenylenediamine, 4-(2-(methylamino)ethyl)aniline, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, and diamine compounds having a carboxy group such as the diamine compounds represented by the following formulae (3b-1) to (3b-4), 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 1,2-bis(4-aminophenyl) ... 1,3-bis(4-aminophenyl)ethane, 1,3-bis(4-aminophenyl)propane, 1,4-bis(4-aminophenyl)butane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,2-bis(4-aminophenoxy)ethane, 1,2-bis(4-amino-2-methylphenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,4-bis(4-aminophenoxy)butane, 1,5-bis(4-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, 4-(2 -(4-aminophenoxy)ethoxy)-3-fluoroaniline, di(2-(4-aminophenoxy)ethyl)ether, 4-amino-4'-(2-(4-aminophenoxy)ethoxy)biphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,7-diaminonaphthalene, 2,2'-bis[4- diamines having a urea bond such as 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2'-bis(4-aminophenyl)propane, and 1,3-bis(4-aminophenethyl)urea; diamines having a photopolymerizable group at the end such as 2-(2,4-diaminophenoxy)ethyl methacrylate and 2,4-diamino-N,N-diallylaniline; diamines having a radical initiation function such as those represented by the following formulas (R1) to (R5); 4,4'-diaminobenzophenone;Examples of the diamine include, but are not limited to, diamines having a photosensitizing function that exhibits a sensitizing effect upon irradiation with light, such as 3'-diaminobenzophenone and 9,9-bis(4-aminophenyl)fluorene; 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine; diamines having a heterocycle such as those shown in the following formulae (z-1) to (z-18); diamines having a diphenylamine skeleton such as those shown in the following formulae (Dp-1) to (Dp-9); diamines having a group "-N(D)-" (D represents a protecting group that is eliminated by heating and replaced with a hydrogen atom, preferably a tert-butoxycarbonyl group) such as those shown in the following formulae (5-1) to (5-10); and diamines having an oxazoline structure such as those shown in the following formulae (Ox-1) to (Ox-2) (hereinafter also referred to as other diamines) from which two amino groups have been removed. [ka] (In formula (3b-1), A 1 represents a single bond, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CHO-, -OCH2-, -COO-, -OCO-, -CON(CH3)- or -N(CH3)CO-, m1 and m2 each independently represent an integer of 0 to 4, and m1+m2 represents an integer of 1 to 4. In formula (3b-2), m3 and m4 each independently represent an integer of 1 to 5. In formula (3b-3), A 2 represents a linear or branched alkyl group having 1 to 5 carbon atoms, and m5 represents an integer of 1 to 5. 3 and A 4 each independently represents a single bond, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CHO-, -OCH2-, -COO-, -OCO-, -CO-N(CH3)- or -N(CH3)CO-, and m6 represents an integer of 1 to 4. [ka] [ka] [ka] (In formulas (R3) to (R5), n is an integer of 1 to 6.) [ka] [ka] [ka]

[0040] The above 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, diamines having a photopolymerizable group at the terminal, diamines represented by the above formulae (R1) to (R5), and diamines represented by the above formulae (z-1) to (z-18) may be used alone or in combination when producing the above polymer component, in order to increase the response speed of a liquid crystal display element using a PSA mode or an SC-PVA mode.

[0041] As the other diamines, among the above, from the viewpoint of suitably obtaining the effects of the present invention, p-phenylenediamine, 3,5-diaminobenzoic acid, 4,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2-(2,4-diaminophenoxy)ethyl methacrylate, 2,4-diamino-N,N-diallylaniline, diamines represented by the above formulas (R1) to (R5), diamines represented by the above formulas (z-1) to (z-18), diamines represented by the above formulas (Dp-1) to (Dp-9), and diamines represented by the above formulas (Ox-1) to (Ox-2) are preferred.

[0042] X3 in the above formula (3-a) and the above formula (3-i) may be the same as X1 in the above formula (1-a) and the above formula (1-i). Examples of R3 in the above formula (3-a) include the same as R1 in the above formula (1-a). Z3 in the above formula (3-a) may be the same as Z1 in the above formula (1-a). In the above formula (3-a) and formula (3-i), each of X3, Y3, R3, and Z3 may be one type or two or more types.

[0043] <Method of Producing Polymer> The polyimide precursor used in the present invention includes polyamic acid, polyamic acid ester, etc. The polyimide precursor used in the present invention can be synthesized by a known method such as that described in International Publication WO2013 / 157586. Specifically, it is synthesized by reacting a diamine component with a tetracarboxylic acid derivative component in a solvent (condensation polymerization). The tetracarboxylic acid derivative component may be tetracarboxylic acid dianhydride or a derivative thereof (tetracarboxylic acid dihalide, tetracarboxylic acid diester, or tetracarboxylic acid diester dihalide). When a part of the polymer contains an amic acid structure, for example, a polymer having an amic acid structure (polyamic acid) can be obtained by reacting a tetracarboxylic acid dianhydride component with a diamine component. The solvent is not particularly limited as long as it dissolves the produced polymer. For example, when obtaining a polymer having a repeating unit represented by the above formula (1-a) in which R1 is a hydrogen atom, a diamine having a structure of -N(Z1)-Y1-N(Z1)- (wherein Y1 and Z1 are defined as in the above formula (1-a)) is used as the diamine component, and a tetracarboxylic acid derivative having the structure of the following formula is used as the tetracarboxylic acid derivative component. [ka] (X1 is defined as in formula (1-a) above.)

[0044] Moreover, polyimide can be obtained by ring-closing (imidization) the polyimide precursor. The imidization ratio in this specification means the ratio of imide groups to the total amount of imide groups derived from tetracarboxylic dianhydride or its derivatives and carboxyl groups (or its derivatives). In polyimide, the imidization ratio does not necessarily have to be 100%, and can be adjusted as desired depending on the application or purpose. The imidization rate of the polyimide contained in the liquid crystal aligning agent of the present invention is from 10 to 95%, preferably from 20 to 95%, and more preferably from 30 to 90%, from the viewpoint of ensuring solubility.

[0045] Methods for imidizing the polyimide precursor include thermal imidization, in which a solution of the polyimide precursor is heated as is, and catalytic imidization, in which a catalyst is added to a solution of the polyimide precursor.

[0046] The temperature when thermally imidizing the polyimide precursor in a solution is 100 to 400° C., preferably 120 to 250° C., and it is preferable to carry out the imidization while removing water generated by the imidization reaction from the system.

[0047] The catalytic imidization of the polyimide precursor can be carried out by adding a basic catalyst and an acid anhydride to a solution of the polyimide precursor and stirring at -20 to 250°C, preferably 0 to 180°C. The amount of the basic catalyst is 0.5 to 30 times by mol, preferably 2 to 20 times by mol, the amount of the acid anhydride is 1 to 50 times by mol, preferably 3 to 30 times by mol, the amount of the amic acid group. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine, among which pyridine is preferred because it has a suitable basicity for promoting the reaction. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride, among which acetic anhydride is preferred because it is easy to purify after the reaction. The imidization rate by catalytic imidization can be controlled by adjusting the amount of the catalyst, the reaction temperature, and the reaction time.

[0048] When recovering the polyimide precursor or polyimide produced from the reaction solution of the polyimide precursor or polyimide, the reaction solution may be poured into a solvent to cause precipitation. Examples of the solvent used for precipitation include methanol, ethanol, isopropyl alcohol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water. The polymer precipitated by pouring into the solvent can be recovered by filtration, and then dried at room temperature or by heating under normal or reduced pressure. In addition, the polymer precipitated and recovered can be redissolved in an organic solvent and the reprecipitation and recovery operation can be repeated 2 to 10 times to reduce impurities in the polymer. Examples of the solvent in this case include alcohols, ketones, and hydrocarbons, and it is preferable to use three or more solvents selected from these because the efficiency of purification is further improved.

[0049] The molecular weight of the polymer used in the present invention is preferably 5,000 to 1,000,000, more preferably 10,000 to 150,000, in terms of weight average molecular weight measured by GPC (Gel Permeation Chromatography), taking into consideration the strength of the liquid crystal alignment film obtained therefrom, workability during film formation, and coating properties.

[0050] The blending ratio of the polymer components used in the manufacturing method of the liquid crystal alignment film of the present invention is not particularly limited, but for example, the total amount of the polymer components contained in the liquid crystal alignment agent is 0.1 to 30 mass %, preferably 3 to 10 mass %. Furthermore, for example, the content of the copolymer (polymer (P-a1+a2)) contained in the liquid crystal aligning agent is 1.5 to 9 mass %, preferably 2.5 to 9 mass %. Furthermore, for example, the total content of the polymer blend (a mixture of polymer (P-a1) and polymer (P-a2)) contained in the liquid crystal alignment agent is 1.5 to 9 mass %, preferably 2.5 to 9 mass %.

[0051] The liquid crystal alignment agent used for producing the liquid crystal alignment film may contain other polymers other than the above copolymer and the above polymer blend. In this case, the content of the other polymers is 0.5% by mass to 15% by mass, preferably 1% by mass to 10% by mass, of the total amount of the polymer components. Examples of the other polymers include polyimide precursors other than the above copolymers and the above polymer blends or imidized polymers thereof, acrylic polymers, methacrylic polymers, polystyrene, polyamides, polysiloxanes, etc.

[0052] The solvent contained in the liquid crystal alignment agent is not particularly limited as long as it can dissolve the polymer, and examples thereof include lactone solvents such as γ-valerolactone and γ-butyrolactone; γ-butyrolactam, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-(n-propyl)-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(tert-butyl)-2-pyrrolidone, N-(n- Lactam solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactamide, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, etc.;4-Hydroxy-4-methyl-2-pentanone, 2,6-dimethyl-4-heptanone (diisobutyl ketone), methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monobutyl ether, propylene glycol diacetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, isoamyl propionate, isoamyl isobutyrate, diisopropyl ether, diisopentyl ether; carbonate solvents such as ethylene carbonate and propylene carbonate, 1-hexanol, cyclohexanol, 1,2-ethanediol, 2,6-dimethyl-4-heptanol (diisobutyl carbinol), etc. These can be used alone or in combination of two or more.;

[0053] Preferred solvent combinations 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, and N-methyl-2-pyrrolidone, γ-butyrolactone and 4-hydroxy-4-methyl-2-pentanone. and diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone and N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol monomethyl ether, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and propylene glycol diacetate, gamma-butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and diisobutyl ketone, gamma-butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and propylene glycol diacetate, N-methyl-2-pyrrolidone, gamma-butyrolactone, propylene glycol monobutyl ether, and diisobutyl ketone, N-methyl-2 N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether, and diisopropyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether, and diisobutyl carbinol, N-methyl-2-pyrrolidone, γ-butyrolactone, and dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone, propylene glycol monobutyl ether, and dipropylene glycol dimethyl ether, etc. The type and content of such a solvent are appropriately selected depending on the coating device, coating conditions, coating environment, etc. of the liquid crystal alignment agent.

[0054] <Liquid crystal alignment agent> The liquid crystal aligning agent of the present invention may contain other components other than those described above, such as a crosslinkable compound, a functional silane compound, a surfactant, a compound having a photopolymerizable group, etc., if necessary.

[0055] The crosslinkable compound can be used for the purpose of increasing the strength of the liquid crystal alignment film. Examples of such crosslinkable compounds include compounds having an isocyanate group or a cyclocarbonate group, or compounds having at least one group selected from the group consisting of lower alkoxyalkyl groups, as described in paragraphs

[0109] to

[0113] of International Publication WO2016 / 047771, as well as compounds having a blocked isocyanate group.

[0056] The blocked isocyanate compound is commercially available, and for example, Coronate AP Stable M, Coronate 2503, 2515, 2507, 2513, 2555, Millionate MS-50 (all manufactured by Tosoh Corporation), Takenate B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, B-882N (all manufactured by Mitsui Chemicals, Inc.) and the like can be preferably used.

[0057] Specific examples of preferred crosslinkable compounds include compounds represented by the following formulas (CL-1) to (CL-11). [ka]

[0058] The above are examples of the crosslinkable compound, and the present invention is not limited to these. The crosslinkable compound used in the liquid crystal aligning agent of the present invention may be one type or a combination of two or more types.

[0059] The content of the other crosslinkable compounds in the liquid crystal aligning agent of the present invention is 0.1 to 150 parts by mass, or 0.1 to 100 parts by mass, or 1 to 50 parts by mass, based on 100 parts by mass of all polymer components.

[0060] The functional silane compound can be used for the purpose of improving the adhesion between the liquid crystal alignment film and the base substrate. Specific examples include the silane compounds described in paragraph

[0019] of International Publication No. 2014 / 119682. The content of the functional silane compound is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, based on 100 parts by mass of all polymer components.

[0061] The surfactant can be used for the purpose of improving the uniformity of the thickness and the surface smoothness of the liquid crystal alignment film. Examples of the compound include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants. Specific examples of these include the surfactants described in paragraph

[0117] of International Publication WO2016 / 047771. The amount of the surfactant used is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, based on 100 parts by mass of all polymer components contained in the liquid crystal alignment agent.

[0062] Examples of compounds having a photopolymerizable group include compounds having one or more polymerizable unsaturated groups, such as an acrylate group or a methacrylate group, in the molecule, such as compounds represented by the following formulas (M-1) to (M-7).

[0063] [ka]

[0064] Furthermore, the liquid crystal aligning agent of the present invention can be added with a nitrogen atom-containing heterocyclic amine compound represented by formula [M1] to formula [M156], more preferably 3-picolylamine and 4-picolylamine, as described in paragraphs

[0194] to

[0200] of International Publication WO2011 / 132751 (published on October 27, 2011), as a compound that promotes charge transfer in the liquid crystal alignment film and promotes charge escape from the element. This amine compound may be added directly to the liquid crystal aligning agent, but it is preferable to add it after making it into a solution with a concentration of 0.1 to 10% by mass, preferably 1 to 7% by mass. This solvent is not particularly limited as long as it dissolves the above polymer.

[0065] An imidization promoter or the like may be added to the liquid crystal aligning agent of the present invention for the purpose of efficiently promoting imidization by heating when baking the coating film.

[0066] The solid content concentration in the liquid crystal alignment agent (the ratio of the total mass of the components other than the solvent of the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) is appropriately selected taking into consideration viscosity, volatility, etc., but is preferably in the range of 0.5 to 15 mass%, more preferably 1 to 10 mass%. The particularly preferred range of solid content varies depending on the method used to apply the liquid crystal alignment agent to the substrate. For example, in the case of the spin coating method, the solid content is particularly preferably in the range of 1.5 to 4.5 mass%. In the case of the printing method, the solid content is particularly preferably in the range of 3 to 9 mass%, thereby making the solution viscosity in the range of 12 to 50 mPa·s. In the case of the inkjet method, the solid content is particularly preferably in the range of 1 to 5 mass%, thereby making the solution viscosity in the range of 3 to 15 mPa·s.

[0067] <Liquid crystal alignment film / Liquid crystal display element> The liquid crystal alignment film of the present invention is obtained from the liquid crystal alignment agent. The liquid crystal alignment film of the present invention can be used for horizontal alignment type or vertical alignment type liquid crystal alignment film, and is particularly suitable for vertical alignment type liquid crystal display elements such as VA mode or PSA mode. The liquid crystal display element of the present invention is provided with the 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) or steps (1) to (4). The liquid crystal alignment film of the present invention can be preferably used for a liquid crystal display element obtained by a manufacturing method of a liquid crystal display element, which comprises applying a coating film onto a pair of substrates having a conductive film to form a coating film, arranging the coating films so as to face each other via a layer of liquid crystal molecules to form a liquid crystal cell, and irradiating the liquid crystal cell with light while applying a voltage between the conductive films of the pair of substrates. More specifically, it is a PSA type liquid crystal display element or a liquid crystal display element for SC-PVA mode, which will be described later. (1) A process of applying a liquid crystal alignment agent onto a substrate The liquid crystal alignment agent of the present invention is applied to one side of a substrate on which a patterned transparent conductive film is provided by an appropriate application method such as a roll coater method, a spin coat method, a printing method, an inkjet method, etc. The substrate is not particularly limited as long as it is a highly transparent substrate, and plastic substrates such as acrylic substrates and polycarbonate substrates can be used in addition to glass substrates and silicon nitride substrates. In addition, in a reflective liquid crystal display element, an opaque material such as a silicon wafer can be used for only one substrate, and in this case, a light-reflecting material such as aluminum can be used for the electrode. (2) The coating is baked After applying the liquid crystal alignment agent, preliminary heating (pre-baking) is preferably performed first for the purpose of preventing dripping of the applied alignment agent. The pre-baking temperature is preferably 30 to 200°C, more preferably 40 to 150°C, and particularly preferably 40 to 100°C. The pre-baking time is preferably 0.25 to 10 minutes, more preferably 0.5 to 5 minutes. Then, it is preferable to further perform a heating (post-baking) step. The post-baking temperature is preferably 80 to 300°C, more preferably 120 to 250°C. The post-baking time is preferably 5 to 200 minutes, more preferably 10 to 100 minutes. The film thickness of the film thus formed is preferably 5 to 300 nm, more preferably 10 to 200 nm.

[0068] The coating film formed in the above step (1) can be used as a liquid crystal alignment film as it is, but the coating film may be subjected to an alignment ability imparting treatment, such as a rubbing treatment in which the coating film is rubbed in a certain direction with a roll wrapped with a cloth made of fibers such as nylon, rayon, or cotton, or a photoalignment treatment in which the coating film is irradiated with polarized or non-polarized radiation.

[0069] In the photo-alignment treatment, the radiation to be irradiated to the coating film may be, for example, ultraviolet light and visible light containing light with a wavelength of 150 to 800 nm. When the radiation is polarized, it may be linearly polarized or partially polarized. When the radiation used is linearly polarized or partially polarized, the radiation may be applied from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these. When non-polarized radiation is applied, the radiation is applied in an oblique direction. (3) Forming the liquid crystal layer (3-1) VA type LCD element Two substrates on which a liquid crystal alignment film is formed are prepared as described above, and liquid crystal is placed between the two substrates arranged opposite each other. Specifically, the following two methods can be mentioned. The first method is a conventionally known method. First, the two substrates are arranged opposite each other with a gap (cell gap) between them so that the liquid crystal alignment films face each other. Next, the peripheries of the two substrates are bonded together using a sealant, and a liquid crystal composition is injected and filled into the substrate surfaces and the cell gap partitioned by the sealant to come into contact with the film surface, and then the injection hole is sealed.

[0070] The second method is a method called ODF (One Drop Fill) method. For example, a UV-curable sealant is applied to a predetermined location on one of the two substrates on which a liquid crystal alignment film is formed, and a liquid crystal composition is dropped at a predetermined number of locations on the liquid crystal alignment film surface. Thereafter, the other substrate is bonded so that the liquid crystal alignment film faces the other substrate, and the liquid crystal composition is spread over the entire surface of the substrate and contacted with the film surface. Next, the entire surface of the substrate is irradiated with UV light to cure the sealant. In either method, it is preferable to further remove the flow alignment during liquid crystal filling by heating to a temperature at which the liquid crystal composition used has an isotropic phase and then slowly cooling to room temperature.

[0071] (3-2) Manufacturing of PSA type liquid crystal display elements The procedure is the same as that of (3-1) above, except that a liquid crystal composition containing a polymerizable compound is injected or dropped. Examples of the polymerizable compound include the polymerizable compounds represented by the above formulas (M-1) to (M-7). (3-3) When a coating film is formed on a substrate using a liquid crystal alignment agent containing a compound having a polymerizable group A method of manufacturing a liquid crystal display element may be adopted in which, after the same procedure as in the above (3-1), a step of irradiating ultraviolet light described later is carried out. According to this method, a liquid crystal display element having excellent response speed can be obtained with a small amount of light irradiation, as in the case of manufacturing the above PSA type liquid crystal display element. The compound having a polymerizable group may be a compound having one or more polymerizable unsaturated groups in the molecule, such as acrylate groups or methacrylate groups, as represented by the above formulas (M-1) to (M-7), and the content thereof is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, relative to 100 parts by mass of all polymer components. The polymerizable group may be contained in a polymer used for a liquid crystal alignment agent, and an example of such a polymer is a polymer obtained by using a diamine component containing a diamine having the above photopolymerizable group at its terminal in a reaction.

[0072] (4) UV irradiation process The liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates obtained in (3-2) or (3-3) above. The voltage applied here can be, for example, 5 to 50 V DC or AC. The light to be irradiated can be, for example, ultraviolet light and visible light containing light with a wavelength of 150 to 800 nm, but ultraviolet light containing light with a wavelength of 300 to 400 nm is preferred. The light source for the irradiation light can be, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, or the like. The light irradiation dose is preferably 1,000 to 200,000 J / m 2 and more preferably 1,000 to 100,000 J / m 2 It is.

[0073] A liquid crystal display element can be obtained by attaching a polarizing plate to the outer surface of the liquid crystal cell. Examples of the polarizing plate to be attached to the outer surface of the liquid crystal cell include a polarizing film called an "H film" made by absorbing iodine while stretching and aligning polyvinyl alcohol, sandwiched between cellulose acetate protective films, and a polarizing plate made of the H film itself.

[0074] The liquid crystal display element of the present invention can be effectively applied to various devices, and can be used in various display devices such as watches, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, liquid crystal televisions, and information displays. EXAMPLES

[0075] The present invention will be described in further detail below with reference to examples, but the present invention is not limited to these examples in any way. <Synthesis of liquid crystal alignment agent> The abbreviations used in the preparation of the liquid crystal alignment agent below are as follows. (acid dianhydride) BODA: Bicyclo[3,3,0]octane-2,4,6,8-tetracarboxylic dianhydride CBDA: 1,2,3,4-cyclobutanetetracarboxylic dianhydride TCA: 2,3,5-tricarboxycyclopentylacetic dianhydride (Diamine) DA-1 to DA-11: Compounds represented by the following formulas (DA-1) to (DA-11), respectively. [ka] [ka] [ka] (Additives) AD-1: A compound represented by the following formula (AD-1): [ka] (solvent) NMP: N-methyl-2-pyrrolidone, BCS: Butyl cellosolve <Molecular weight measurement> Measurement equipment: room temperature gel permeation chromatography (GPC) (SSC-7200) manufactured by Senshu Scientific Co., Ltd., column: Shodex column (KD-803, KD-805 in series), column temperature: 50°C, eluent: N,N-dimethylformamide (additives: lithium bromide monohydrate (LiBr·H2O) 30 mmol / L, phosphoric acid·anhydrous crystal (o-phosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 mL / L), flow rate: 1.0 mL / min, standard sample for creating calibration curve: TSK standard polyethylene oxide manufactured by Tosoh Corporation (molecular weights: approximately 900,000, 150,000, 100,000, 30,000), and polyethylene glycol manufactured by Polymer Laboratory Co., Ltd. (molecular weights: approximately 12,000, 4,000, 1,000).

[0076] <Measurement of imidization rate> 20 mg of polyimide powder was placed in an NMR sample tube (Kusano Scientific NMR Sampling Tube Standard φ5), 1.0 mL of deuterated dimethyl sulfoxide (DMSO-d6, 0.05% TMS mixture) was added, and the mixture was sonicated to completely dissolve. This solution was measured by 500 MHz proton NMR using a JEOL Datum NMR analyzer (JNW-ECA500). The chemical imidization rate was determined by the following formula using a proton derived from a structure that does not change before and after imidization as a reference proton and the peak integrated value of this proton and the proton peak integrated value derived from the NH group of the amic acid appearing around 9.5 to 10.0 ppm: In the formula, x is the proton peak integrated value derived from the NH group of the amic acid, y is the peak integrated value of the reference proton, and α is the ratio of the number of reference protons to one proton of the NH group of the amic acid in the case of polyamic acid (imidization rate 0%). Imidization rate (%) = (1-α·x / y) × 100

[0077] <Synthesis Example 1> BODA (2.50 g, 10.0 mmol), DA-1 (2.76 g, 14.0 mmol), and DA-8 (2.28 g, 6.0 mmol) were dissolved in NMP (30.2 g) and reacted at 60° C. for 3 hours, after which CBDA (1.92 g, 9.8 mmol) and NMP (7.7 g) were added and reacted at 40° C. for 4 hours to obtain polyamic acid solution (1). The number average molecular weight Mn of this polyamic acid was 10,360 and the weight average molecular weight Mw was 30,350.

[0078] <Synthesis Example 2> BODA (2.50 g, 10.0 mmol), DA-2 (2.96 g, 14.0 mmol), and DA-8 (2.28 g, 6.0 mmol) were dissolved in NMP (31.0 g) and reacted at 60° C. for 3 hours, after which CBDA (1.92 g, 9.8 mmol) and NMP (7.7 g) were added and reacted at 40° C. for 4 hours to obtain polyamic acid solution (2). The Mn of this polyamic acid was 12,140 and the Mw was 37,600.

[0079] <Synthesis Example 3> BODA (2.50 g, 10.0 mmol), DA-4 (2.79 g, 14.0 mmol), and DA-8 (2.28 g, 6.0 mmol) were dissolved in NMP (30.3 g) and reacted at 60° C. for 3 hours, after which CBDA (1.92 g, 9.8 mmol) and NMP (7.7 g) were added and reacted at 40° C. for 4 hours to obtain polyamic acid solution (3). The Mn of this polyamic acid was 12,630 and the Mw was 36,540.

[0080] <Synthesis Example 4> BODA (2.50 g, 10.0 mmol), DA-3 (5.90 g, 14.0 mmol), and DA-8 (2.28 g, 6.0 mmol) were mixed in NMP (38.3 g) and reacted at 60° C. for 3 hours, after which CBDA (1.81 g, 9.2 mmol) and NMP (7.8 g) were added and reacted at 40° C. for 3 hours to obtain polyamic acid solution (4). The Mn of this polyamic acid was 12,340 and the Mw was 46,260.

[0081] <Synthesis Example 5> BODA (2.50g, 10.0mmol), DA-1 (1.58g, 8.0mmol), DA-6 (1.94g, 8.0mmol) and DA-9 (1.58g, 4.0mmol) were mixed in NMP (30.4g) and reacted at 60°C for 3 hours, after which CBDA (1.94g, 9.9mmol) and NMP (7.7g) were added and reacted at 40°C for 3 hours to obtain a polyamic acid solution (5-a). The Mn of this polyamic acid was 11,450 and the Mw was 37,590. NMP (6.0g) and BCS (8.0g) were added to the obtained polyamic acid solution (5-a) (6.0g) and stirred at room temperature for 2 hours to obtain a polyamic acid solution (5).

[0082] <Synthesis Example 6> The polyamic acid solution (5-a) (20.0 g) obtained in Synthesis Example 5 was diluted to 6.5 mass% with NMP, and then acetic anhydride (4.27 g) and pyridine (1.33 g) were added as imidization catalysts and reacted at 50° C. for 3 hours. The reaction solution was poured into methanol (270 mL), and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 60° C. to obtain a polyimide powder. The imidization rate of this polyimide powder was 37%, Mn was 10,980, and Mw was 34,300. NMP (22.0 g) was added to the obtained polyimide powder (3.0 g), and the mixture was stirred at 70° C. for 12 hours to dissolve, to obtain a polyimide solution (1).

[0083] <Synthesis Example 7> BODA (2.50 g, 10.0 mmol), DA-2 (1.69 g, 8.0 mmol), DA-6 (1.94 g, 8.0 mmol) and DA-9 (1.58 g, 4.0 mmol) were mixed in NMP (30.8 g) and reacted at 60 ° C for 3 hours, then CBDA (1.94 g, 9.9 mmol) and NMP (7.8 g) were added and reacted at 40 ° C for 3 hours to obtain polyamic acid solution (6-a). Mn of this polyamic acid was 10,860 and Mw was 36,010. NMP (6.0 g) and BCS (8.0 g) were added to the obtained polyamic acid solution (6-a) (6.0 g) and stirred at room temperature for 2 hours to obtain polyamic acid solution (6).

[0084] <Synthesis Example 8> The polyamic acid solution (6-a) (20.0 g) obtained in Synthesis Example 7 was diluted to 6.5 mass% with NMP, and then acetic anhydride (4.23 g) and pyridine (1.31 g) were added as imidization catalysts and reacted at 50° C. for 3 hours. The reaction solution was poured into methanol (270 mL), and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 60° C. to obtain a polyimide powder. The imidization rate of this polyimide powder was 53%, Mn was 9,920, and Mw was 32,300. NMP (22.0 g) was added to the obtained polyimide powder (3.0 g), and the mixture was stirred at 70° C. for 12 hours to dissolve, to obtain a polyimide solution (2).

[0085] <Synthesis Example 9> BODA (2.50 g, 10.0 mmol), DA-4 (1.59 g, 8.0 mmol), DA-6 (1.94 g, 8.0 mmol) and DA-9 (1.58 g, 4.0 mmol) were mixed in NMP (30.4 g) and reacted at 60 ° C for 3 hours, then CBDA (1.92 g, 9.8 mmol) and NMP (7.7 g) were added and reacted at 40 ° C for 3 hours to obtain polyamic acid solution (7-a). Mn of this polyamic acid was 11,030 and Mw was 33,050. NMP (6.0 g) and BCS (8.0 g) were added to the obtained polyamic acid solution (7-a) (6.0 g) and stirred at room temperature for 2 hours to obtain polyamic acid solution (7).

[0086] <Synthesis Example 10> The polyamic acid solution (7-a) (20.0 g) obtained in Synthesis Example 9 was diluted to 6.5 mass% with NMP, and then acetic anhydride (4.27 g) and pyridine (1.32 g) were added as imidization catalysts and reacted at 50° C. for 3 hours. The reaction solution was poured into methanol (270 mL), and the resulting precipitate was filtered off. The precipitate was washed with methanol and dried under reduced pressure at 60° C. to obtain a polyimide powder. The imidization rate of this polyimide powder was 58%, Mn was 10,490, and Mw was 31,280. NMP (22.0 g) was added to the obtained polyimide powder (3.0 g), and the mixture was stirred at 70° C. for 12 hours to dissolve, to obtain a polyimide solution (3).

[0087] <Synthesis Example 11> BODA (2.50g, 10.0mmol), DA-3 (3.37g, 8.0mmol), DA-7 (1.42g, 6.0mmol) and DA-8 (2.28g, 6.0mmol) were mixed in NMP (38.3g) and reacted at 60°C for 3 hours, then CBDA (1.95g, 9.9mmol) and NMP (7.8g) were added and reacted at 40°C for 3 hours to obtain a polyamic acid solution. The Mn of this polyamic acid was 9,100 and the Mw was 24,540. The obtained polyamic acid solution (20.0g) was diluted to 6.5 mass% with NMP, and then acetic anhydride (3.54g) and pyridine (1.10g) were added as imidization catalysts and reacted at 80°C for 3 hours. This reaction solution was poured into methanol (230mL) and the resulting precipitate was filtered off. This precipitate was washed with methanol and dried under reduced pressure at 60°C to obtain a polyimide powder. The imidization rate of this polyimide powder was 78%, Mn was 9,040, and Mw was 21,020. NMP (22.0 g) was added to the obtained polyimide powder (3.0 g) and dissolved by stirring at 70°C for 12 hours to obtain a polyimide solution (4).

[0088] <Synthesis Example 12> TCA (4.37g, 19.5mmol), DA-1 (1.58g, 8.0mmol), DA-6 (1.94g, 8.0mmol) and DA-9 (1.58g, 4.0mmol) were mixed in NMP (37.9g) and reacted at 60°C for 6 hours to obtain a polyamic acid solution. The Mn of this polyamic acid was 11,860 and the Mw was 45,870. The obtained polyamic acid solution (20.0g) was diluted to 6.5 mass% with NMP, and then acetic anhydride (8.53g) and pyridine (1.32g) were added as imidization catalysts and reacted at 80°C for 4 hours. This reaction solution was poured into methanol (285mL) and the obtained precipitate was filtered off. This precipitate was washed with methanol and dried under reduced pressure at 60°C to obtain a polyimide powder. The imidization rate of this polyimide powder was 66%, Mn was 10,500, and Mw was 41,300. NMP (22.0 g) was added to the obtained polyimide powder (3.0 g) and dissolved by stirring at 70° C. for 12 hours, to obtain a polyimide solution (5).

[0089] <Synthesis Example 13> TCA (4.46 g, 19.9 mmol), DA-4 (1.59 g, 8.0 mmol), DA-6 (1.45 g, 6.0 mmol) and DA-8 (2.28 g, 6.0 mmol) were mixed in NMP (39.1 g) and reacted at 60 ° C for 6 hours to obtain a polyamic acid solution. The Mn of this polyamic acid was 11,900 and the Mw was 44,800. The obtained polyamic acid solution (20.0 g) was diluted to 6.5 mass % with NMP, and then acetic anhydride (6.66 g) and pyridine (1.29 g) were added as imidization catalysts and reacted at 100 ° C for 2 hours. This reaction solution was poured into methanol (243 mL) and the obtained precipitate was filtered off. This precipitate was washed with methanol and dried under reduced pressure at 60 ° C to obtain a polyimide powder. The imidization rate of this polyimide powder was 73%, Mn was 10,500, and Mw was 40,300. NMP (22.0 g) was added to the obtained polyimide powder (3.0 g) and dissolved by stirring at 70° C. for 12 hours, to obtain a polyimide solution (6).

[0090] <Synthesis Example 14> TCA (4.42 g, 19.7 mmol), DA-3 (3.37 g, 8.0 mmol), DA-8 (2.28 g, 6.0 mmol) and DA-7 (1.42 g, 6.0 mmol) were mixed in NMP (46.0 g) and reacted at 60 ° C for 6 hours to obtain a polyamic acid solution. The Mn of this polyamic acid was 11,750 and the Mw was 54,510. The obtained polyamic acid solution (20.0 g) was diluted to 6.5 mass % with NMP, and then acetic anhydride (5.65 g) and pyridine (1.09 g) were added as imidization catalysts and reacted at 80 ° C for 2 hours. This reaction solution was poured into methanol (239 mL) and the obtained precipitate was filtered off. This precipitate was washed with methanol and dried under reduced pressure at 60 ° C to obtain a polyimide powder. The imidization rate of this polyimide powder was 71%, Mn was 10,700, and Mw was 48,300. NMP (22.0 g) was added to the obtained polyimide powder (3.0 g) and dissolved by stirring at 70° C. for 12 hours, to obtain a polyimide solution (7).

[0091] <Synthesis Example 15> BODA (2.50g, 10.0mmol), DA-5 (0.99g, 5.0mmol), DA-10 (0.66g, 2.0mmol), DA-7 (1.43g, 6.0mmol) and DA-9 (2.76g, 7.0mmol) were mixed in NMP (33.4g) and reacted at 60°C for 3 hours, then CBDA (1.93g, 9.8mmol) and NMP (7.7g) were added and reacted at 40°C for 3 hours to obtain a polyamic acid solution. The Mn of this polyamic acid was 11,900 and the Mw was 44,800. The obtained polyamic acid solution (20.0g) was diluted to 6.5% by mass with NMP, and then acetic anhydride (3.96g) and pyridine (1.23g) were added as imidization catalysts and reacted at 50°C for 3 hours. This reaction solution was poured into methanol (270 mL), and the resulting precipitate was filtered off. This precipitate was washed with methanol and dried under reduced pressure at 60°C to obtain a polyimide powder. The imidization rate of this polyimide powder was 59%, Mn was 9,260, and Mw was 23,400. NMP (22.0 g) was added to the obtained polyimide powder (3.0 g), and the mixture was stirred at 70°C for 12 hours to dissolve it, and then NMP (5.0 g) and BCS (20.0 g) were added and stirred at room temperature for 2 hours to obtain a polyimide solution (8).

[0092] <Synthesis Example 16> TCA (4.45g, 19.8mmol), DA-5 (1.39g, 7.0mmol), DA-10 (1.65g, 5.0mmol), DA-7 (0.94g, 4.0mmol) and DA-11 (3.03g, 4.0mmol) were mixed in NMP (45.9g) and reacted at 60°C for 6 hours to obtain a polyamic acid solution. The Mn of this polyamic acid was 10,360 and the Mw was 27,730. The obtained polyamic acid solution (20.0g) was diluted to 6.5 mass% with NMP, and then acetic anhydride (7.10g) and pyridine (1.10g) were added as imidization catalysts and reacted at 80°C for 4 hours. This reaction solution was poured into methanol (240mL) and the obtained precipitate was filtered off. This precipitate was washed with methanol and dried under reduced pressure at 60°C to obtain a polyimide powder. The imidization rate of this polyimide was 68%, Mn was 10,210, and Mw was 23,320. NMP (22.0 g) was added to the obtained polyimide powder (3.0 g) and dissolved by stirring at 70° C. for 12 hours, and then NMP (5.0 g) and BCS (20.0 g) were added and stirred at room temperature for 2 hours to obtain a polyimide solution (9).

[0093] The specifications of each polymer obtained in the above synthesis examples are as shown in Table 1 below. [Table 1]

[0094] <Preparation of Liquid Crystal Alignment Agent>

[0095] [Example 1] NMP (6.0 g) and BCS (8.0 g) were added to the polyamic acid solution (1) (6.0 g) obtained in Synthesis Example 1, and the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal aligning agent (A-1).

[0096] [Example 2, Comparative Examples 1 and 2] Liquid crystal alignment agents (A-2), (B-1), and (B-2) of Example 2 and Comparative Examples 1 and 2 were obtained in the same manner as in Example 1, except that polyamic acid solutions (2), (3), and (4) were used instead of polyamic acid solution (1).

[0097] [Example 3] NMP (2.0 g) and BCS (8.0 g) were added to the polyimide solution (1) (10.0 g) obtained in Synthesis Example 6, and the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (A-3).

[0098] [Examples 4 and 5, Comparative Examples 3 to 6] The liquid crystal alignment agents (A-4), (A-5), (B-3) to (B-6) of Examples 4 and 5 and Comparative Examples 3 to 6 were obtained in the same manner as in Example 3, except that the polyimide solutions (2), (5), (3), (4), (6), and (7) were used instead of the polyimide solution (1).

[0099] [Example 6] The polyamic acid solution (5) (7.0 g) obtained in Synthesis Example 5, the polyimide solution (8) (3.0 g) obtained in Synthesis Example 15, and AD-1 (0.06 g) were mixed to obtain a liquid crystal alignment agent (C-1).

[0100] [Example 7, Comparative Example 7] Liquid crystal alignment agents (C-2) and (C-3) of Example 7 and Comparative Example 7 were obtained in the same manner as in Example 6, except that polyamic acid solutions (6) and (7) were used instead of polyamic acid solution (5).

[0101] [Comparative Example 8] The liquid crystal alignment agent (B-4) (7.0 g) obtained in Comparative Example 4, the polyimide solution (9) (3.0 g) obtained in Synthesis Example 16, and AD-1 (0.06 g) were mixed to obtain a liquid crystal alignment agent (C-4).

[0102] [Table 2]

[0103] The liquid crystal alignment agents (A-1) to (A-5), (B-1) to (B-6), and (C-1) to (C-4) obtained as described above were confirmed to be homogeneous solutions without any abnormalities such as turbidity or precipitation. Using the obtained liquid crystal alignment agents, evaluation of transmittance, preparation of liquid crystal cells, evaluation of voltage holding ratio, residual DC voltage, and evaluation of afterimage characteristics were performed.

[0104] [Transmittance evaluation] The liquid crystal alignment agents (A-1) to (A-4), (B-1) to (B-3), and (C-1) to (C-4) obtained in the examples and comparative examples were spin-coated on a quartz substrate and dried on a hot plate at 70°C for 90 seconds. Then, the substrate was baked in an IR (infrared) oven at 230°C for 20 minutes to form a coating film with a thickness of 100 nm, thereby obtaining a substrate with a liquid crystal alignment film. The substrate with the liquid crystal alignment film was placed on the inside, and another quartz substrate was used to sandwich a refractive liquid (contact liquid manufactured by Shimadzu Device Manufacturing Co., Ltd.) in order to prevent light interference. The transmittance was evaluated using a UV-3600 (manufactured by Shimadzu Corporation) as a measuring device, at a temperature of 25°C, and a scanning wavelength of 380 to 800 nm. At that time, a substrate with a refractive liquid sandwiched between two quartz substrates without coating was used as a reference. The evaluation was based on the transmittance at a wavelength of 550 nm, and the values ​​are shown in Table 3 below.

[0105] [Preparation of liquid crystal display elements for evaluation of voltage holding ratio and residual DC characteristics] Using the liquid crystal alignment agents (A-1) to (A-5), (B-1) to (B-6), and (C-1) to (C-4) obtained in the examples and comparative examples, liquid crystal cells were prepared according to the procedure shown below. The liquid crystal alignment agent was spin-coated on a glass substrate with an ITO electrode, dried on a hot plate at 70°C for 90 seconds, and then baked in an IR oven at 230°C for 20 minutes to form a liquid crystal alignment film with a thickness of 100 nm. Two substrates with this liquid crystal alignment film were prepared, and a bead spacer with a diameter of 4 μm (manufactured by JGC Catalysts and Chemicals, Shinshikyu, SW-D1) was applied on one of the liquid crystal alignment films, and a thermosetting sealant (manufactured by Mitsui Chemicals, XN-1500T) was printed on it. Next, the surface of the other substrate on which the liquid crystal alignment film was formed was placed inside, and the other substrate was bonded to the previous substrate, and the sealant was cured to prepare an empty cell. Liquid crystal MLC-3023 (Merck) was injected into this empty cell by a reduced pressure injection method to prepare a liquid crystal cell. Next, while a DC voltage of 15 V was applied to this liquid crystal cell, UV light was applied from the outside of the liquid crystal cell at 10 J / cm2 through a filter that cuts off 325 nm or less. 2 The UV illuminance was measured using a UV-MO3A manufactured by ORC Corp. After that, in order to inactivate the unreacted polymerizable compound remaining in the liquid crystal cell, the cell was irradiated with UV (UV lamp: FLR40SUV32 / A-1) for 30 minutes using a UV-FL irradiation device manufactured by Toshiba Lighting & Technology Corp. in a state where no voltage was applied.

[0106] [Preparation of liquid crystal display element for evaluation of image retention characteristics] Using the liquid crystal alignment agents (A-1) to (A-5), (B-1) to (B-5), and (C-1) to (C-4) obtained in the examples and comparative examples, liquid crystal cells were prepared according to the procedure shown below. The liquid crystal alignment agent was spin-coated on the ITO surface of an ITO electrode substrate (length: 35 mm, width: 30 mm, thickness: 0.7 mm) on which an ITO electrode pattern with a pixel size of 200 μm × 600 μm and a line / space of 3 μm each was formed, and a glass substrate (length: 35 mm, width: 30 mm, thickness: 0.7 mm) with an ITO electrode on which a photospacer with a height of 3.2 μm was patterned, and then dried on a hot plate at 70 ° C for 90 seconds, and baked in an IR oven at 230 ° C for 20 minutes to form a liquid crystal alignment film with a thickness of 100 nm. The ITO electrode substrate on which this ITO electrode pattern is formed is divided into four areas in a cross-checkered pattern, so that each of the four areas can be driven separately. Next, a sealant (Mitsui Chemicals XN-1500T) was printed. Next, the other substrate was attached to the previous substrate with the surface on which the liquid crystal alignment film was formed facing inward, and the sealant was cured to create an empty cell. Liquid crystal MLC-3023 (Merck) was injected into this empty cell by a reduced pressure injection method to create a liquid crystal cell. With a DC voltage of 15 V applied to this liquid crystal cell, UV light was applied at 10 J / cm2 from the outside of the liquid crystal cell, passing through a filter that cuts off 325 nm or less. 2 The UV illuminance was measured using a UV-MO3A manufactured by ORC Corp. After that, in order to inactivate the unreacted polymerizable compound remaining in the liquid crystal cell, the cell was irradiated with UV (UV lamp: FLR40SUV32 / A-1) for 30 minutes using a UV-FL irradiation device manufactured by Toshiba Lighting & Technology Corp. in a state where no voltage was applied.

[0107] [Evaluation of voltage holding ratio] The voltage retention rate was measured using a liquid crystal cell for evaluating the voltage retention rate after UV irradiation. A voltage of 1V was applied for 60μs in a 60℃ hot air circulating oven, and the voltage was measured 16.67msec later, and the extent to which the voltage was retained was calculated as the voltage retention rate. To measure the voltage retention rate, a VHR-1 manufactured by Toyo Corporation was used. The values ​​are shown in Table 3 below. The higher the value, the better the result.

[0108] [aging] The liquid crystal cell after PSA treatment was left in a high-temperature, high-humidity oven set at 85°C and 85% humidity for 3 to 7 days to be aged under high-temperature, high-humidity conditions. At this time, the voltage retention ratio was measured initially, after PSA treatment, and after aging. The decrease in voltage retention ratio due to aging (Δ(after PSA treatment - after aging)) was also calculated. The results are shown in Table 3 below.

[0109] [Evaluation of residual DC voltage] A 30Hz, 7.8Vpp square wave with 2V DC superimposed was applied to the liquid crystal cell for voltage holding ratio evaluation prepared above for 100 hours at 25℃, and the voltage remaining in the liquid crystal cell one hour after the DC voltage was turned off (residual DC voltage) was measured using the flicker elimination method. This value is an index of image retention caused by DC accumulation, and when this value is 50mV or less, the image retention characteristics are excellent, i.e., "good", and when it is greater than 50mV, it is "poor". The results are shown in Table 3 below.

[0110] [Afterimage characteristics] Using the liquid crystal cell for evaluating image retention characteristics prepared above, an AC voltage of 60 Hz and 20 Vp-p was applied to two of the four pixel areas, which were diagonally aligned, and the cell was driven at a temperature of 25°C for 168 hours. After that, all four pixel areas were driven with an AC voltage of 5 Vp-p, and the brightness difference between the pixels was visually observed. A state in which the brightness difference was almost unnoticeable was rated as "good," and a state in which the brightness difference was noticeable was rated as "poor." The evaluation results are shown in Table 3. [Table 3] *1) Aging for 3 days, *2) Aging for 7 days

[0111] As shown in Table 3, the liquid crystal alignment films obtained using the liquid crystal alignment agents (A-1) to (A-4), (C-1), and (C-2) of Examples 1 to 4, 6, and 7, which contain polyamic acid or polyimide obtained using the diamine having the structure represented by formula (S1) and the diamine having the structure represented by formula (2c), had higher transmittance than the liquid crystal alignment films obtained using the corresponding liquid crystal alignment agents (B-1) to (B-3), (C-3), and (C-4) of Comparative Examples 1 to 3, 7, and 8. Note that a 1% difference in transmittance is a significant difference in the technical field. In addition, it is found that the liquid crystal alignment agent obtained in the examples can provide a liquid crystal alignment film having a high voltage retention ratio in the evaluation of voltage retention ratio and aging. It is also found that the liquid crystal alignment film exhibits good characteristics in the evaluation of residual DC voltage and afterimage characteristics.

[0112] The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2020-060306, filed on March 30, 2020, are hereby incorporated by reference as the disclosure of the specification of the present invention.

Claims

1. A first repeating unit (a1) selected from the group consisting of a repeating unit represented by the following formula (1-a) and a repeating unit represented by the following formula (1-i), A liquid crystal aligning agent comprising a polymer component having a repeating unit represented by the following formula (2-a) and a second repeating unit (a2) selected from the group consisting of a repeating unit represented by the following formula (2-i): 【Chemistry 1】 【Chemistry 2】 (X １ , X ２ represents a tetravalent organic group. １ Y is any of the structures represented by the following formulas (S1-1) to (S1-7). ２ represents a divalent organic group represented by the following formula (2c). １ , R ２ Each of Z independently represents a hydrogen atom or a monovalent organic group. １ , Z ２ each independently represents a hydrogen atom or a monovalent organic group. 【Chemistry 3】 (R １ represents 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. ｐ is -(CH ２ ) ａ -(a is an integer of 2 to 15), -CONH-, -NHCO-, -CO-N(CH ３ )-, -NH-, -O-, -CH ２ O-, -CH ２ represents —OCO—, —COO—, or —OCO—. １ represents an oxygen atom or -COO-* (wherein the bond marked with "*" is (CH ２ ) ａ２ (combines with), A ２ represents an oxygen atom or *-COO- (where the bond marked with "*" is (CH ２ ) ａ２ and a １ , a ３ are each independently an integer of 0 or 1; ２ is an integer from 1 to 10, and Cy represents a 1,4-cyclohexylene group or a 1,4-phenylene group. 【Chemistry 4】 (R represents a hydrogen atom or a monovalent organic group. * represents a bond.)

2. The liquid crystal aligning agent according to claim 1, wherein the polymer component contains at least one polymer selected from the group consisting of a polyimide precursor having the repeating unit (a1) and the repeating unit (a2) in the same molecule and an imidized polymer thereof.

3. The polymer component contains at least one polymer (P-a1) selected from the group consisting of polyimide precursors having the repeating unit (a1) and imidized polymers thereof, and at least one polymer (P-a2) selected from the group consisting of polyimide precursors having the repeating unit (a2) and imidized polymers thereof. The liquid crystal aligning agent according to claim 1, comprising a mixture of the above.

4. The liquid crystal aligning agent according to any one of claims 1 to 3, wherein in the formula (2c), R represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxyalkyl group, or a phenyl group.

5. In the formula (2-a) and the formula (2-i), Y ２ is a group obtained by removing two amino groups from a carbazole selected from the group consisting of 3,6-diaminocarbazole, 9-methyl-3,6-diaminocarbazole, 9-ethyl-3,6-diaminocarbazole, and 9-phenyl-3,6-diaminocarbazole. The liquid crystal aligning agent according to any one of claims 1 to 4.

6. The polymer component further comprises a third repeating unit (a3) ​​selected from the group consisting of a repeating unit represented by the following formula (3-a) and a repeating unit represented by the following formula (3-i): The liquid crystal aligning agent according to any one of claims 1 to 5. 【Chemistry 5】 (X ３ represents a tetravalent organic group. ３ is any of the structures represented by the formulas (S1-1) to (S1-7). ３ , two Zs ３ are R in formula (1-a), １ , Z １ (Same meaning as above.)

7. The polymer component is selected from the group consisting of a polyimide precursor having the first repeating unit (a1) and the second repeating unit (a2) in the same molecule and an imidized polymer thereof (P-a1+a2), and a polyimide precursor having the first repeating unit (a1) and the third repeating unit (a3) ​​in the same molecule and an imidized polymer thereof (P-a1+a3). The liquid crystal aligning agent according to claim 6, comprising a mixture of at least one polymer selected from the group consisting of a polyimide precursor having the first repeating unit (a1) and the third repeating unit (a3) ​​in the same molecule and an imidized polymer thereof.

8. The polymer component is composed of at least one polymer selected from the group consisting of a polyimide precursor obtained by using a tetracarboxylic acid component containing a tetracarboxylic acid dianhydride represented by the following formula (3) or a derivative thereof, and an imidized polymer thereof. The liquid crystal aligning agent according to any one of claims 1 to 7. 【Chemistry 6】 (X represents a structure selected from the group consisting of the following (x-1) to (x-13).) 【Chemistry 7】 (R １ ~R ４ R each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group. ５ and R ６ Each of j and k is independently a hydrogen atom or a methyl group. １ and A ２ each independently represents a single bond, -O-, -CO-, -COO-, phenylene, a sulfonyl group, or an amide group. *1 is a bond bonded to one acid anhydride group, and *2 is a bond bonded to the other acid anhydride group. In the formula (x-13), ２ may be the same or different.)

9. The liquid crystal aligning agent according to any one of claims 1 to 8, further comprising at least one crosslinking compound selected from the group consisting of a compound having an isocyanate group or a cyclocarbonate group, a compound having a lower alkoxyalkyl group, and a compound having a blocked isocyanate group.

10. The liquid crystal aligning agent according to claim 3, wherein the mass ratio of the content of the polymer (P-a2) to the content of the polymer (P-a1) is 5 / 95 to 95 / 5.

11. A liquid crystal alignment film formed by using the liquid crystal aligning agent according to any one of claims 1 to 10.

12. A liquid crystal display device comprising the liquid crystal alignment film according to claim 11.

13. A method for manufacturing a liquid crystal display element, comprising the steps of: applying the liquid crystal alignment agent according to any one of claims 1 to 12 onto a pair of substrates having conductive films to form coating films; arranging the coating films so as to face each other via a layer of liquid crystal molecules to form a liquid crystal cell; and irradiating the liquid crystal cell with light while applying a voltage between the conductive films of the pair of substrates.

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