Manufacturing methods of liquid crystal alignment agents, liquid crystal alignment films, liquid crystal display elements, and liquid crystal display elements

Abstract

This invention provides a liquid crystal alignment agent, etc., which provides a liquid crystal alignment film with excellent resistance to AC image retention and low pretilt angle characteristics. A liquid crystal alignment agent contains component (A) and component (B). Component (A): Polymer (A), selected from at least one of the following groups: a tetracarboxylic acid dianhydride represented by formula (Tc) comprising 100 mol% of all tetracarboxylic acid derivative components; a diamine represented by formula (dAL) comprising 60% or more of all diamine components; a polyimide precursor; and polyimides. (B) Composition: Polymer (B) is selected from at least one of the following groups: a tetracarboxylic acid dianhydride represented by formula (Tf) comprising at least 5 mol% of all tetracarboxylic acid derivative components; a polyimide precursor comprising a reaction product containing a diamine represented by formula (dAL) and a diamine represented by formula (dn); and polyimides. The meanings of the symbols in the above formula are as defined in the specification.

Description

[Technical Field]

[0001] This invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, a method for manufacturing a liquid crystal display element, and a liquid crystal display element. [Previous Technology]

[0002] Liquid crystal display elements used in LCD TVs, navigators, smartphones, etc., typically have a liquid crystal alignment film within the element to control the alignment of liquid crystals. The liquid crystal alignment film functions to control the alignment of liquid crystal molecules in a specific direction within the liquid crystal display element. For example, a liquid crystal display element has a structure in which liquid crystal molecules, forming a liquid crystal layer, are held together by liquid crystal alignment films formed on the surfaces of a pair of substrates. The liquid crystal molecules are aligned in a specific direction by the liquid crystal alignment film and respond to the voltage applied to electrodes located between the substrate and the liquid crystal alignment film. As a result, the liquid crystal display element displays the desired image by utilizing the alignment changes caused by the response of the liquid crystal molecules. To date, liquid crystal alignment films have primarily used polyimide-based liquid crystal alignment films, which are formed by coating a solution of polyimide precursors such as polyamic acid and soluble polyimide as the main components onto a glass substrate and then calcining.

[0003] In recent years, with the increasing performance of liquid crystal display (LCD) elements, in addition to applications such as large-screen and high-resolution LCD televisions, LCD elements are also used in automotive applications (e.g., car navigation systems, dashboards), surveillance cameras, and medical camera screens. Due to the requirements of viewing angle characteristics, some researchers have explored transverse electric field methods such as IPS (In-Plane Switching) and FFS (Fringe Field Switching) (Patent Document 1, Patent Document 2). [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] WO2017-061575 Publication No. [Patent Document 2] WO2020-116585 Publication No. [Summary of the Invention]

[0005] (The problem the invention aims to solve)

[0006] The liquid crystal alignment film used in liquid crystal display elements with IPS driving and FFS driving methods needs to have alignment regulation force to suppress image retention (hereinafter also referred to as AC image retention) caused by long-term AC driving. As liquid crystal display elements with rapidly increasing precision are gradually adopting backlights with higher brightness than before, the specifications for display defects such as "image retention" are becoming increasingly stringent.

[0007] Patent document 1 describes a liquid crystal alignment film for photoalignment of liquid crystal display elements suitable for IPS driving mode and FFS driving mode.

[0008] Furthermore, Patent Document 2 describes a liquid crystal alignment film obtained from a liquid crystal alignment agent containing two types of polyacrylic acids, which exhibits high resistance to AC image retention. On the other hand, the liquid crystal display elements used in the above applications require a lower pretilt angle than before due to the need for viewing angle characteristics. However, after review, the inventors of this case found that the effect of reducing the pretilt angle of the liquid crystal alignment film is not sufficient.

[0009] In view of the above circumstances, the present invention aims to provide a liquid crystal alignment agent that yields a liquid crystal alignment film with excellent resistance to AC image retention and low pretilt angle characteristics, the liquid crystal alignment film, and a liquid crystal display element using the liquid crystal alignment film. (Solution to the problem)

[0010] In order to achieve the above-mentioned objectives, the inventors of this case have made great efforts in research and found that by using a liquid crystal alignment agent containing a specific polymer component to form a liquid crystal alignment film, it is effective to achieve the above-mentioned objectives, and thus the present invention was completed.

[0011] This invention is based on this knowledge and insight, and the following are the main points.

[0012] A liquid crystal alignment agent, characterized by containing the following (A) component and (B) component: (A) polymer (A), which is selected from at least one of the following groups: a polyimide precursor composed of a tetracarboxylic acid derivative component containing 100 mol% of all tetracarboxylic acid derivative components and a diamine component containing 60% or more of all diamine components, representing a reaction product of a polyimide precursor and a diamine component containing 60% or more of all diamine components; (B) polymer (B), which is selected from a tetracarboxylic acid derivative component containing 5 mol% or more of all tetracarboxylic acid derivative components and a diamine component containing 60% or more of the reaction product of a tetracarboxylic acid derivative component containing 60% or more of all diamine components, representing a reaction product of a tetracarboxylic acid derivative component containing 60% or more of all tetracarboxylic acid derivative components and a diamine component containing 60% or more of all tetracarboxylic acid derivative ... The reaction product of a diamine represented by AL and a diamine component represented by the following formula (dn) is a polyimide precursor, and a polyimide consisting of a polyimide of a polyimide precursor.

[0013] [Chemical 1]

[0014] R 11 to R 14 each independently represent 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 organogroup having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group, and at least one of R 11 to R 14 represents a group other than a hydrogen atom as defined above.

[0015] [Chemical 2]

[0016] A represents a divalent organogroup having the radical "*11-(CH 2) nO-*12" (*11 represents an atomic bond with an oxygen atom or an atomic bond with a carbon atom constituting the benzene ring, and *12 represents an atomic bond. n is an integer from 1 to 5.). Any hydrogen atom of the aforementioned benzene ring bonded to the NH 2 group can also be replaced by a monovalent group.

[0017] [Chemical 3]

[0018] X f is a tetravalent organic group with an alicyclic structure having 5 or more member rings.

[0019] [Chemical 4]

[0020] Y represents a divalent organic group having a structure containing nitrogen atoms, selected from a heterocycle containing a nitrogen atom and a group consisting of a nitrogen-containing group "*21-NR-*22" (*21 and *22 represent atomic bonds formed with carbon atoms constituting an aromatic ring. However, 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, wherein the aforementioned monovalent organic group is bonded to a nitrogen atom by a carbon atom other than a carbonyl carbon.) Furthermore, throughout this specification, the following terms and abbreviations have the following meanings: Halogen atoms are fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc., preferably fluorine atoms. * represents an atomic bond. Also, Boc represents a terbutoxycarbonyl group. (Effects of the Invention)

[0021] According to the liquid crystal alignment agent of the present invention, a liquid crystal alignment agent that provides a liquid crystal alignment film with excellent resistance to AC image retention and low pretilt angle characteristics can be obtained. Furthermore, a liquid crystal display element having this liquid crystal alignment film exhibits excellent viewing angle characteristics and high display quality.

[0022] The mechanism by which the present invention achieves the above-mentioned effects is not necessarily clear, but it is generally speculated as follows. That is, it is believed that by using two polymers as polymer components used as liquid crystal alignment agents, and by using diamines with specific alkyl chain lengths in the raw material components of both polymers, a highly linear polymer will be formed, thus exhibiting an improved resistance to AC image retention.

[0023] Furthermore, by using two different polymer components, the two polymers can be easily separated into two layers, which is believed to be able to take into account both high resistance to AC ghosting and low pretilt angle characteristics.

Implementation Method

[0025] The following describes the components contained in the liquid crystal alignment agent of the present invention, and other components that may be arbitrarily incorporated as needed. The polymers (A) and (B) contained in the liquid crystal alignment agent of the present invention are polyimide precursors obtained using tetracarboxylic acid derivative components and diamine components, or amides of the polyimide precursors, i.e., polyimides. The polyimide precursor is a polymer that can be obtained by amide-imidizing polyacrylic acid, polyacrylic ester, etc.

[0026] Polymers (A) and (B) are preferably polyimide precursors, with polyamide being even more preferred, from the viewpoint of ideally achieving the effects of the present invention. <Polymer (A)> The polyimide precursor of the above-mentioned polymer (A) is polyamide (A'), which can be obtained by polymerization of a diamine component and a tetracarboxylic acid derivative component. In the manufacturing of the polymer (A) contained in the liquid crystal alignment agent of the present invention, the content of the diamine represented by the following formula (dAL) is 60% or more of the total diamine component. The diamine represented by formula (dAL) can be used alone or in combination of two or more.

[0027] [Chemical 5]

[0028] A represents a divalent organic group having the radical "*11-(CH2)nO-*12" (*11 represents an atomic bond with an oxygen atom or an atomic bond with a carbon atom constituting the benzene ring, and *12 represents an atomic bond. n is an integer from 1 to 5.). Any hydrogen atom of the aforementioned benzene ring bonded to the NH2 group can also be replaced by a monovalent group. By having A in the above formula (dAL) in the above state, the resistance to AC remnants is improved, and when using the two polymers, they are moderately miscible, resulting in low pretilt angle characteristics.

[0029] From the perspective of obtaining high liquid crystal alignment, *11 is a better atomic bond with oxygen atoms.

[0030] From the perspective of obtaining low pretilt angle characteristics, it is more ideal for n in the base "*11-(CH 2) nO-*12" to be an integer from 2 to 5, and integers of 2 and 5 are even more ideal.

[0031] Regarding the two amine groups in the above formula (d AL), from the point of view of obtaining high liquid crystal alignment, it is better to have them in the para position relative to A.

[0032] In the above formula (d AL), A is preferably a divalent organic group with 1 to 18 carbons, more preferably a carbon number of 1 to 14 carbons, and even more preferably a carbon number of 1 to 12 carbons, from the point of view of ideally obtaining the effect of the present invention.

[0033] In the above formula (d AL), the monovalent group may include halogen atoms, alkyl groups with 1 to 10 carbon atoms (preferably 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms), alkenyl groups with 2 to 10 carbon atoms (preferably 2 to 5 carbon atoms, more preferably 2 to 3 carbon atoms), alkoxy groups with 1 to 10 carbon atoms (preferably 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms), fluoroalkyl groups with 1 to 10 carbon atoms (preferably 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms), fluoroalkenyl groups with 2 to 10 carbon atoms (preferably 2 to 5 carbon atoms, more preferably 2 to 3 carbon atoms), fluoroalkoxy groups with 1 to 10 carbon atoms (preferably 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms), carboxyl groups, hydroxyl groups, alkoxycarbonyl groups with 1 to 10 carbon atoms (preferably 2 to 5 carbon atoms, more preferably 2 to 3 carbon atoms), cyano groups, nitro groups, etc.

[0034] From the point of view of ideally obtaining the effects of the present invention, the diamines represented by the above formula (dAL) are preferred, considering the diamines represented by the formulas (dAL-1) to (dAL-9).

[0035] [Chemical 6]

[0036] In the above formulas (d AL-1)~(d AL-2) and (d AL-4)~(d AL-5), considering the viewpoint of obtaining low pretilt angle characteristics, n is more ideally 2~5.

[0037] Considering the need to obtain low pretilt angle characteristics, it is more ideal for m and n in the above formula (d AL-3) to be 2~5 independently.

[0038] In the above formula (d AL-6), n is preferably 2 to 4, with 2 or 4 being more ideal. In the above formula (d AL-6), m1 and m2 are each preferably 1 to 3, with 1 to 2 being more ideal. Furthermore, the sum of m1, m2, and n is 3 to 16. Considering the viewpoint of obtaining low pretilt angle characteristics, 3 to 12 is better, with 3 to 10 being more ideal.

[0039] In the above formulas (d AL-7) and (d AL-9), considering the viewpoint of obtaining low pretilt angle characteristics, n is more ideally 2~5.

[0040] In the above formula (d AL-8), n is better if it is 1~4, better if it is 1~3, and more ideal if it is 1~2. In the above formula (d AL-8), m1 and m2 are each better if they are 1~4, better if they are 1~3, and more ideal if they are 1~2. Also, the sum of m1, m2 and n is 3~15. Considering the point of view of obtaining low pretilt angle characteristics, 3~14 is better, and 3~12 is more ideal.

[0041] In the above formulas (d AL-1)~(d AL-9), the two amine groups are para-positioned, which is better than the divalent organic group that links the benzene ring, considering the viewpoint of obtaining high liquid crystal alignment.

[0042] In the constituent components of the polymer (A) described above, the ideal content of the diamine represented by the above formula (dAL) is preferably 60 mol% or more, more preferably 70 mol% or more, and more preferably 80 mol% or more. When other diamines described below are used in combination, the diamine represented by the above formula (dAL) is preferably 95 mol% or less, more preferably 90 mol% or less, and even more preferably 85 mol% or less.

[0043] The diamine component used in the manufacture of the polymer (A) contained in the liquid crystal alignment agent of the present invention, in addition to the diamines mentioned above, can use various diamines (hereinafter also referred to as other diamines) depending on the desired characteristics of the liquid crystal alignment agent. The aforementioned other diamines can be the following. Among the other diamines, from the viewpoint of ideally obtaining the effects of the present invention, diamines without side chain groups having 4 or more carbon atoms (except for the protecting groups that are removed and replaced by hydrogen atoms by heating, as described later) are preferred. One diamine can be used alone or in combination of two or more.

[0044] The above formula (dn) represents diamines, p-phenylenediamine, 2,3,5,6-tetramethylp-phenylenediamine, 2,5-dimethylp-phenylenediamine, m-phenylenediamine, 2,4-dimethylm-phenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene, and other phenylenediamines; 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 2,2'-difluoro-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-diaminobiphenyl, 2,2'-bis( Diamines containing a biphenyl structure, such as trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 4,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'-diaminobiphenyl, and 2,3'-diaminobiphenyl; 1,2-bis(6-amino-2-naphthyl)ethane, 1,2-bis(6-amino-2-naphthyl)ethane, 6-[2-(4-aminophenoxy)ethoxy]-2-naphthylamine, 1,5-diaminonaphthalene, 1,6-diaminonaphthalene, 1,7-diaminonaphthalene, 2,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,7- Diamines with a naphthalene structure, such as diaminonaphthalene; diamines with photoalignment groups, such as 4,4'-diaminoazobenzene or diaminodiphenylacetylene; diamines with amide or urea bonds, such as those represented by formulas (h-1) to (h-5); 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 1,2-bis(4-aminophenyl)ethane, 1,2-bis(3-aminophenyl)ethane, 1,3-bis(4-aminophenyl)propane, 1,3-bis(3-aminophenyl)propane, 1,4-bis(4-aminophenyl)butane, 1,4-bis... (3-aminophenyl)butane, 1,5-bis(4-aminophenyl)pentane, 1,5-bis(3-aminophenyl)pentane, 1,6-bis(4-aminophenyl)hexane, 1,6-bis(3-aminophenyl)hexane, 4,4'-diaminodiphenyl ketone, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene, diamines represented by the following formula (do); 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol; 4,4'-diamino-3,3'-dihydroxybiphenyl;2,4-Diaminobenzoic acid, 2,5-Diaminobenzoic acid, 3,5-Diaminobenzoic acid, 4,4'-Diaminobiphenyl-3-carboxylic acid, 4,4'-Diaminodiphenylmethane-3-carboxylic acid, 1,2-bis(4-aminophenyl)ethane-3-carboxylic acid, 4,4'-Diaminobiphenyl-3,3'-dicarboxylic acid, 4,4'-Diaminobiphenyl-2,2'-dicarboxylic acid, 3,3'-Diaminobiphenyl-4,4'-dicarboxylic acid, 3,3'-Diaminobiphenyl-2,4'-dicarboxylic acid, 4,4'-Diaminodiphenylmethane-3,3'-dicarboxylic acid, 1,2- Diamines with carboxyl groups, such as bis(4-aminophenyl)ethane-3,3'-dicarboxylic acid and 4,4'-diaminodiphenyl ether-3,3'-dicarboxylic acid; diamines with carboxyl groups, such as 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 1-(4-aminophenyl)-1,3,3-trimethyl-1H-dihydroindene-5-amine, and 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine; and tert-terminated photopolymerizable methacrylates such as 2-(2,4-diaminophenoxy)ethyl and 2,4-diamino-N,N-diallylaniline. Diamines with a steroidal skeleton, such as cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-3,5-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholesteryl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, lanosteryl 3,5-diaminobenzoate, and 3,6-bis(4-aminobenzoyloxy)cholestane; diamines represented by formulas (V-1) to (V-2); and diamines with a "-N(D)-" group (D represents a protecting group that is removed and replaced by a hydrogen atom upon heating), etc., as shown in formulas (5-1) to (5-9). Preferred to be a tert-butoxycarbonyl group. Diamines of the form (except for diamines represented by formula (dn)); diamines having siloxane bonds, such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane; m-xylene diamine, 1,3-propane diamine, tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), and diamines with two amino groups bonded to any of the formulas (Y-1) to (Y-167) as described in WO2018 / 117239.

[0045] [Chemical 7]

[0046] [Chemical 8]

[0047] When there are two or more m, the two or more m can be the same or different. One or more hydrogen atoms on the benzene ring can also be substituted by a monovalent group. An example of formula (d 0) is given later.

[0048] [Chemical 9]

[0049] In formula (V-1), m and n are integers from 0 to 3 (but 1 ≤ m + n ≤ 4), j is an integer of 0 or 1, X 1 represents -(CH 2) a- (a is an integer from 1 to 15), -CONH-, -NHCO-, -CO-N(CH 3)-, -NH-, -O-, -CH 2O-, -CH 2-OCO-, -COO-, or -OCO-. R 1 represents a fluorine atom, an alkyl group containing fluorine atoms with 1 to 10 carbon atoms, an alkoxy group containing fluorine atoms with 1 to 10 carbon atoms, an alkyl group with 3 to 10 carbon atoms, an alkoxy group with 3 to 10 carbon atoms, or an alkoxyalkyl group with 3 to 10 carbon atoms. In equation (V-2), X2 represents -O-, -CH2O-, -CH2-OCO-, -COO-, or -OCO-. When two of m, n, X1, and R1 exist, they each independently possess the above definitions.

[0050] [Chemical 10]

[0051] A specific example of the monovalent base in the above formula (do) can be listed as the structure of the monovalent base in the above formula (d AL).

[0052] For the diamine represented by the above formula (do), considering the viewpoint of making the pretilt angle low, it is preferable to use the diamine, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether and 4,4'-diaminodiphenyl ether represented by the following formulas (do-1)~(do-6).

[0053] [Chemical 11]

[0054] In the manufacture of the polymer (A) contained in the liquid crystal alignment agent of the present invention, the content of tetracarboxylic acid dianhydride represented by the above formula (T c) is 100 moles of all tetracarboxylic acid derivative components.

[0055] By containing the specific tetracarboxylic dianhydride described above, the configuration during acetylation is restricted. Therefore, the obtained polymer (A) exhibits high stereoregularity, resulting in a liquid crystal alignment film with excellent resistance to AC image retention. Furthermore, the specific tetracarboxylic dianhydride described above has a substituted structure, thus increasing the probability that the polymer (A) component with high liquid crystal alignment is concentrated on the surface layer, which is believed to ideally achieve the effects of the present invention. In formula (Tc), examples of alkyl groups having 1 to 6 carbons, preferably 1 to 3, include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, dibutyl, tributyl, n-pentyl, etc. Examples of alkenyl groups having 2 to 6 carbons, preferably 2 to 4, include vinyl, propenyl, butenyl, etc., which can be linear or branched. The 2-6 carbon atoms in R11-R14 are preferably 2-3 alkynyl groups, such as ethynyl, 1-propynyl, 2-propynyl, etc. The 1-6 carbon atoms containing fluorine atoms in R11-R14 are preferably 1-3 monovalent organogroups, such as fluoromethyl, trifluoromethyl, pentafluoroethyl, pentafluoropropyl, etc. A more ideal combination of R11-R14, considering the low pretilt angle characteristic, preferably has R11 and R14 with the same structure, and R12 and R13 with the same structure. Furthermore, it is preferable that R11-R14 is a hydrogen atom or a methyl group, and at least one of R11-R14 is methyl; more preferably, at least two of R11-R14 are methyl. More ideally, R11 and R14 are methyl groups, and R12 and R13 are hydrogen atoms. <Polymer (B)> The diamine component used in the manufacture of the polymer (B) in the liquid crystal alignment agent of this invention contains a diamine represented by the above formula (dAL) and a diamine represented by the above formula (dn). The diamine represented by the above formula (dAL) and the diamine represented by the above formula (dn) can be used individually or in combination.

[0056] The ideal state of the diamine represented by the above formula (d AL) used in the manufacture of polymer (B) is the same as the ideal state of the diamine represented by the above formula (d AL) used in the manufacture of polymer (A).

[0057] In the above-mentioned polymer (B), the content of diamine represented by the above formula (dAL) is preferably 5 to 80 mol% of all diamine components used in the synthesis of polymer (B), 10 to 70 mol% is more preferred, and 40 to 60 mol% is even more ideal.

[0058] The nitrogen-containing heterocycle in the above formula (dn) includes, for example: pyrrole ring, imidazole ring, pyrazole ring, triazole ring, pyridine ring, pyrimidine ring, terpinen ring, pyridine ring, indole ring, benzimidazole ring, purine ring, quinoline ring, isoquinoline ring, acetidine ring, quinoline ring, phthaloline ring, triphthaloline ring, carbazole ring, acridine ring, piperidine ring, piperidine ring, pyrroleidine ring, hexamethyleneimine ring, etc. Among these, pyridine ring, pyrimidine ring, pyridine ring, piperidine ring, piperidine ring, quinoline ring, carbazole ring, or acridine ring are preferred.

[0059] The monovalent organic group of R in the above formula (dn) is, for example: alkyl such as methyl, ethyl, propyl; alkenyl such as vinyl; cycloalkyl such as cyclohexyl; aryl such as phenyl, methylphenyl, alkoxy (e.g., methoxy, ethoxy), etc. R is preferably a hydrogen atom or methyl.

[0060] Specific examples of diamines represented by the above formula (dn) include: 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, or diamines represented by the following formulas (dn-1) to (dn-3).

[0061] [Chemical 12]

[0062] In formula (d n-1), m1 and m1' are each an integer from 1 to 2. n1 is an integer from 1 to 3. R1 is synonymous with the R of the amino group represented by "*21-NR-*22" above.

[0063] When there are multiple R1 and m1', the multiple R1 and m1' can be the same or different.

[0064] In formula (d n-2), X 2 represents a nitrogen-containing heterocyclic group with a monovalent nitrogen atom. Specific examples of nitrogen-containing heterocycles in this monovalent nitrogen-containing heterocyclic group can be listed in the structure of the nitrogen-containing heterocycles illustrated in the above formula (dn).

[0065] n1 is an integer from 1 to 2, and n2 is an integer that satisfies n1 + n2 = 2. L1 and L2 are each independently a single bond, -CO-, an alkyl group with 1 to 6 carbon atoms, or a divalent organic group in which -O- or -CO- is inserted between or at the end of the carbon-carbon bond of the alkyl group and is bonded to the nitrogen atom by a carbon atom. R represents a hydrogen atom or a methyl group.

[0066] When there are multiple X2, L2, and R, the multiple X2, L2, and R can be the same or different.

[0067] In formula (d n-3), X 3 represents a divalent group of a nitrogen-containing heterocycle. Specific examples of such nitrogen-containing heterocycles can be listed in the structures of the nitrogen-containing heterocycles illustrated in formula (dn) above.

[0068] Ar 3 represents a divalent aromatic cyclic group or a divalent saturated heterocyclic group containing a nitrogen atom. Specific examples of aromatic rings in divalent aromatic cyclic groups include benzene rings, naphthyl rings, anthracene rings, pyridine rings, pyrimidine rings, pyridine rings, triphenyl ether rings, pyrrole rings, imidazole rings, pyrazole rings, quinoline rings, isoquinoline rings, carbazole rings, benzimidazole rings, indole rings, quinoline rings, and acridine rings. Specific examples of saturated heterocyclic groups containing nitrogen atoms in divalent nitrogen atom-containing saturated heterocyclic groups include piperidine rings and piperidine rings. Any hydrogen atom in the aromatic cyclic group and the saturated heterocyclic group containing a nitrogen atom can also be replaced by a monovalent group. The structures of monovalent groups can be exemplified by the monovalent groups shown in the above formula (d AL).

[0069] L 3 represents a single bond, -(CH 2) n- (n is an integer from 1 to 6), -NR'-, -(CH 2) n-NR'- (n is an integer from 1 to 6), -O-, -NR'-CO-, -CO-NR'-, -O-CO-, or -CO-O-, and R' represents a hydrogen atom, methyl, or third butoxycarbonyl.

[0070] m3 and m3' are each an integer from 0 to 2, and either m3 or m3' is an integer greater than 1.

[0071] When there are multiple Ar 3 and L 3, the multiple Ar 3 and L 3 can be the same or different.

[0072] Also, the NH 2 groups at both ends of formula (d n-3) are bonded to the carbon atoms that form the aromatic ring.

[0073] Ideal specific examples of diamines represented by the above formulas (d n-1) to (d n-3) can be listed as diamines represented by the following formulas (Dp-1) to (Dp-6) and diamines represented by the following formulas (z-1) to (z-14).

[0074] [Chemical 13]

[0075] [Chemical 14]

[0076] [Chemical 15]

[0077] In the above-mentioned polymer (B), the content of diamine represented by the above formula (dn) is preferably 20-95 mol% of all diamine components used in the manufacture of polymer (B), more preferably 30-90 mol%, and ideally 40-60 mol%.

[0078] In the manufacture of the polymer (B) contained in the liquid crystal alignment agent of the present invention, the diamine component used, in addition to the above-mentioned diamine, can be various diamines (hereinafter also referred to as other diamines (b)) depending on the characteristics of the liquid crystal alignment agent required.

[0079] Other diamines (b), such as compounds of diamines exemplified in the manufacture of the polymer (A) described above. Among the other diamines (b), from the viewpoint of ideally obtaining the effects of the present invention, diamines without side chain groups having four or more carbon atoms (except for the protecting groups that are removed and replaced by hydrogen atoms upon heating) are preferred. The other diamines (b) described above may be used individually or in combination of two or more.

[0080] In the manufacture of the polymer (B) contained in the liquid crystal alignment agent of the present invention, the content of the tetracarboxylic acid derivative component represented by the above formula (Tf) is more than 5 mol% of the total tetracarboxylic acid derivative component.

[0081] By containing a tetracarboxylic dianhydride represented by the above formula (Tf), the decrease in molecular weight of polymer (B) is suppressed, thus obtaining a liquid crystal alignment film with high liquid crystal alignment and excellent resistance to AC image retention. Furthermore, polymer (B) has a specific tetracarboxylic dianhydride that is not easily amided, thus obtaining a polymer with many hydrophilic groups such as carboxyl groups, and obtaining a liquid crystal alignment film with excellent two-layer separation between polymer (A) and polymer (B). Therefore, a liquid crystal alignment film with high liquid crystal alignment and excellent resistance to AC image retention, as described above, can be obtained.

[0082] In the aforementioned formula (Tf), the tetravalent organic group of Xf with an alicyclic structure of 5 or more members is preferably a tetravalent organic group with an alicyclic structure of 5 to 8 members, and even more preferably a tetravalent organic group with an alicyclic structure of 5 to 7 members. Furthermore, an alicyclic structure of 5 or more members refers to a polycyclic alicyclic structure in which the anhydride group is bonded, wherein each ring in this polycyclic structure contains 5 or more atoms constituting the ring. Also, the aforementioned alicyclic structure only needs to be bonded to at least one of the two anhydride groups, and can also simultaneously possess an alicyclic structure, a chain hydrocarbon structure, and an aromatic ring structure.

[0083] An ideal specific example of Xf can be listed as a tetravalent organic group represented by any of the formulas (Xf-1) to (Xf-17). From the viewpoint of ideally obtaining the effects of the present invention, Xf is more ideally represented by (Xf-1) to (Xf-4).

[0084] [Chemical 16]

[0085] Regarding the total amount of tetracarboxylic dianhydrides represented by the above formula (Tf), from the viewpoint of obtaining the effect of the present invention, it is preferable that the total amount of all tetracarboxylic acid derivative components used in the manufacture of polymer (B) is 10 mol% or more, and 20 mol% or more is even more preferred. In addition to the tetracarboxylic acid dianhydrides represented by the above formula (Tf), the tetracarboxylic acid derivative components used in the manufacture of polymer (B) in the liquid crystal alignment agent of the present invention may also use tetracarboxylic acid dianhydrides other than those represented by the above formula (Tf) (also collectively referred to as other tetracarboxylic acid dianhydrides (b)) depending on the desired characteristics of the liquid crystal alignment agent. The aforementioned other tetracarboxylic acid dianhydrides (b) may be used alone or in combination of two or more.

[0086] Specific examples of other tetracarboxylic dianhydrides (b) may include alicyclic tetracarboxylic dianhydrides, noncyclic aliphatic tetracarboxylic dianhydrides, or aromatic tetracarboxylic dianhydrides other than those represented by the above formula (T f).

[0087] Here, alicyclic tetracarboxylic dianhydrides are acidic dianhydrides obtained by intramolecularly dehydrating four carboxyl groups, including at least one carboxyl group bonded by an alicyclic structure. However, none of these four carboxyl groups are bonded to an aromatic ring. Furthermore, it is not necessary for it to be composed solely of an alicyclic structure; a portion of it may also have a chain hydrocarbon structure or an aromatic ring structure. Acyclic alicyclic tetracarboxylic dianhydrides are acidic dianhydrides obtained by intramolecularly dehydrating four carboxyl groups bonded by a chain hydrocarbon structure. However, it is not necessary for it to be composed solely of a chain hydrocarbon structure; a portion of it may also have an alicyclic structure or an aromatic ring structure. Aromatic tetracarboxylic dianhydrides are acidic dianhydrides obtained simply by intramolecularly dehydrating four carboxyl groups, including at least one carboxyl group bonded by an aromatic ring; there are no particular restrictions.

[0088] Among the other tetracarboxylic dianhydrides (b) mentioned above, the non-cyclic aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, or aromatic tetracarboxylic dianhydrides are preferably tetracarboxylic dianhydrides represented by the above formula (T c) or tetracarboxylic dianhydrides represented by the following formula (t).

[0089] [Chemical 17]

[0090] In the formula, X1 is selected from the structure of the following formulas (X1-1)~(X1-10).

[0091] [Chemical 18]

[0092] [Chemical 19]

[0093] In formulas (X1-9) to (X1-10), j and k are integers of 0 or 1, and A1 and A2 independently represent single bonds, -O-, -CO-, -COO-, phenyl, sulfonyl, or amide bonds. Multiple A2s can be the same or different. * indicates an atomic bond. Ideal concrete examples of the above formulas (X1-9) to (X1-10) can be listed in the following formulas (XR-1) to (XR-14). Considering the viewpoint of improving the alignment of liquid crystals, the above formulas (X1-9) to (X1-10) are more ideal than (XR-1) to (XR-8), and (XR-1), (XR-4) to (XR-6), and (XR-8) are even more ideal.

[0094] [Chemical 20]

[0095] [Chemical 21]

[0096] When the liquid crystal alignment agent of the present invention contains other tetracarboxylic acid dianhydrides (b), the content of the other tetracarboxylic acid dianhydrides (b) is preferably 5 mol% to 95 mol%, more preferably 10 to 90 mol%, and even more preferably 20 to 80 mol% of all tetracarboxylic acid derivative components used in the manufacture of polymer (B). Furthermore, in this case, the total amount of tetracarboxylic acid dianhydrides represented by the above formula (Tf) is preferably 5 to 95 mol%, more preferably 10 to 90 mol%, and even more preferably 20 to 80 mol% of all tetracarboxylic acid derivative components.

[0097] Regarding the content ratio of the above-mentioned components (A) and (B), from the perspective of obtaining the effect of the present invention, the content ratio of components (A) and (B) by mass ratio of [(A) component] / [(B) component] can be 10 / 90~90 / 10, 20 / 80~90 / 10, or 20 / 80~80 / 20. <Manufacturing of Polymer (A) and Polymer (B)> (Synthesis of Polyamide) The polyimide precursor polyamide contained in the liquid crystal alignment agent of the present invention can be manufactured, for example, by the following method. Furthermore, the tetracarboxylic acid derivative used in the manufacturing of polymer (A) or polymer (B) can be not only tetracarboxylic dianhydride, but also its derivatives, tetracarboxylic dihalides, tetracarboxylic dialkyl esters, tetracarboxylic dialkyl ester dihalides, etc. Specifically, the synthesis can be achieved by reacting a tetracarboxylic acid derivative containing the aforementioned tetracarboxylic acid dianhydride with a diamine containing the aforementioned diamine in the presence of an organic solvent, preferably at -20 to 150°C, more preferably at 0 to 50°C, preferably for 0.5 to 24 hours, and more preferably for 1 to 12 hours (condensation).

[0098] Specific examples of organic solvents used in the above reactions include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidineone, etc. Furthermore, when the polymer has high solvent solubility, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, diethylene glycol monomethyl ether, or diethylene glycol monoethyl ether can be used. Two or more of these solvents can also be mixed.

[0099] The reaction of polyamide can be carried out at any concentration, preferably 1-50% by mass, more preferably 5-30% by mass. The reaction can be carried out at a high concentration initially, followed by the addition of solvent. During the reaction, the ratio of the total moles of the diamine components to the total moles of the tetracarboxylic acid components is preferably 0.8-1.2. Similar to conventional polycondensation reactions, the closer this mole ratio is to 1.0, the larger the molecular weight of the resulting polyamide.

[0100] The polyamide obtained by the above reaction can be precipitated and recovered by injecting the reaction solution into a poor solvent while stirring it thoroughly. Alternatively, the precipitation can be repeated several times, washed with a poor solvent, and then dried at room temperature or by heating to obtain refined polyamide powder. The poor solvent is not particularly limited, and examples include water, methanol, ethanol, hexane, butylceroxose, acetone, toluene, etc. (Synthesis of polyamide esters) Polyamide esters can be obtained by known methods such as: [I] reacting the polyamide 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, etc. (Synthesis of Polyimide) Polyimide can also be obtained by cyclizing (nitroimidizing) the aforementioned polyimide precursors such as polyamides or polyamide esters. Furthermore, the nitroimidization rate referred to in this specification is the ratio of nitroimide groups to the total amount of nitroimide groups and carboxyl groups (or their derivatives) derived from tetracarboxylic dianhydride or its derivatives. The nitroimidization rate does not necessarily need to be 100% and can be adjusted arbitrarily according to the application and purpose. [End-capping agent] When synthesizing polymers (A) and (B) of this invention, tetracarboxylic acid derivatives containing tetracarboxylic dianhydride, diamine components, and appropriate end-capping agents can also be used to synthesize end-sealed polymers.

[0101] End-capping agents, such as acetic anhydride, maleic anhydride, natriuretic 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 and other acid-anhydrides; dibutyl dicarbonate, diallyl dicarbonate and other dicarbonate diester compounds; acrylonitrile chloride, methacrylonitrile chloride, nicotinic acid chloride and other chlorocarbonyl compounds; Monoamine compounds such as aniline, 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.

[0102] The ratio of the capping agent to the total 100 moles of diamine used is preferably 0.1 to 30 moles, and more preferably 0.1 to 20 moles.

[0103] When recovering polyacrylic acid from the reaction solution, the reaction solution can be added to a solvent to precipitate it. Solvents used for precipitation include methanol, ethanol, isopropanol, acetone, hexane, butylceryl ketone, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water. After filtering and recovering the polyacrylic acid that has been added to the solvent and precipitated, it can be dried at room temperature or under normal or reduced pressure. Furthermore, if the process of re-dissolving the precipitated polymer in an organic solvent and then re-precipitating it is repeated 2 to 10 times, impurities in the polymer can be reduced. Solvents used in this process include, for example, alcohols, ketones, or hydrocarbons. Using three or more solvents selected from these sources will result in higher purification efficiency, which is ideal.

[0104] Regarding the molecular weight of the polymers (A) and (B) used in this invention, when considering the strength of the liquid crystal alignment film obtained therefrom, the workability during film formation, and the coating properties, a weight-average molecular weight of 5,000 to 1,000,000 as determined by the GPC (Gel Permeation Chromatography) method is more ideal, and more preferably 10,000 to 150,000.

[0105] The total content of polymers contained in the liquid crystal alignment agent of the present invention can also be appropriately varied depending on the desired coating thickness. From the viewpoint of forming a uniform and defect-free coating, 1% by mass or more is more ideal, while from the viewpoint of the storage stability of the solution, 10% by mass or less is more preferred. In particular, the ideal total polymer content is 2 to 8% by mass.

[0106] The liquid crystal alignment agent of the present invention may also contain polymers other than polymer (A) and polymer (B). Specific examples of other polymers include polymers selected from the group consisting of polyimide precursors or polymers other than polymer (A) and polymer (B), such as polyimide, polysiloxane, polyester, polyamide, polyurea, polyurethane, polyorganosiloxane, cellulose derivatives, polyacetal, polystyrene derivatives, poly(styrene-maleic anhydride) copolymer, poly(isobutylene-maleic anhydride) copolymer, poly(vinyl ether-maleic anhydride) copolymer, poly(styrene-phenylmaleimide) derivative, and poly(meth)acrylate. Specific examples of poly(styrene-maleic anhydride) copolymers include SMA1000, 2000, 3000 (manufactured by Cray Valley), GSM301 (manufactured by Gifushellac), etc. Specific examples of poly(isobutylene-maleic anhydride) copolymers include ISOBAM-600 (manufactured by Kuraray), and specific examples of poly(vinyl ether-maleic anhydride) copolymers include GANTREZ AN-139 (methyl vinyl ether maleic anhydride resin, manufactured by ISP JAPAN).

[0107] Other polymers may be used alone or in combination of two or more. Ideally, the proportion of other polymers should be less than 90 parts by mass relative to the total number of polymers contained in the liquid crystal alignment agent (100 parts by mass), 10 to 90 parts by mass is better, and 20 to 80 parts by mass is more ideal.

[0108] The liquid crystal alignment agent of the present invention is preferably a liquid composition obtained by dissolving or dispersing the above-mentioned polymers (A) and (B) in an organic solvent. Specifically, the organic solvent contained in the above-mentioned liquid crystal alignment agent is not particularly limited as long as the polyacrylic acid can be uniformly dissolved. Examples include N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-dimethyllactamide, N,N-dimethylpropionic acid, tetramethylurea, N,N-diethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolidinedione, methyl ethyl ketone, cyclohexanone, and cyclopentanone. Ketones, 3-methoxy-N,N-dimethylpropionic acid, 3-butoxy-N,N-dimethylpropionic acid, N-(n-propyl)-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(tert-butyl)-2-pyrrolidone, N-(n-pentyl)-2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone (these are also collectively referred to as "good solvents"), etc. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropionic acid, 3-butoxy-N,N-dimethylpropionic acid, or γ-butyrolactone are preferred. The content of 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 ideally 30-80% by mass.

[0109] Furthermore, the organic solvent contained in the liquid crystal alignment agent should preferably be a mixed solvent, in addition to the solvents mentioned above, that improves the coatability and surface smoothness of the coating film when applying the liquid crystal alignment agent (also known as a poor solvent). Specific examples of the poor solvents used are as follows, but not limited to these. The content of the poor solvent is ideally 1-80% by mass of the total solvents contained in the liquid crystal alignment agent, more preferably 10-80% by mass, and especially preferably 20-70% by mass. The type and content of the poor solvent can be appropriately selected according to the coating equipment, coating conditions, coating environment, etc. of the liquid crystal alignment agent.

[0110] Unsuitable solvents, such as: diisopropyl ether, diisobutyl ether, diisobutylmethanol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propyl carbonate, ethyl 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-Butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monopropyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol acetate, 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.

[0111] 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.

[0112] Ideal solvent combinations of good and bad solvents include N-methyl-2-pyrrolidone with γ-butyrolactone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone with γ-butyrolactone and propylene glycol monobutyl ether, N,N-dimethyllactamidine with diisobutyl ketone, N-methyl-2-pyrrolidone with ethyl 3-ethoxypropionate and dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone with ethyl 3-ethoxypropionate and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone with ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether, N-ethyl-2-pyrrolidone with ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether, N,N-dimethyllactamidine with ethylene glycol monobutyl ether, and N,N-dimethyllactamidine with propylene glycol. Diacetate, N-ethyl-2-pyrrolidone with diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone with diethylene glycol monoethyl ether and butyl ceroxoxetine, N-methyl-2-pyrrolidone with diethylene glycol monomethyl ether and butyl ceroxoxetine, N,N-dimethyllactamine with diethylene glycol diethyl ether, N-methyl-2-pyrrolidone with γ-butyrolactone and 4-hydroxy-4-methyl-2-pentanone with diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone with N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone, N-ethyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone and diisocyanate Butyl ketone, N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with dipropylene glycol monomethyl ether, N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with propylene glycol monobutyl ether, N-methyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with propylene glycol diacetate, N-ethyl-2-pyrrolidone with 4-hydroxy-4-methyl-2-pentanone with dipropylene glycol dimethyl ether, γ-butyrolactone with 4-hydroxy-4-methyl-2-pentanone with diisobutyl ketone, γ-butyrolactone with 4-hydroxy-4-methyl-2-pentanone with propylene glycol diacetate, N-methyl-2-pyrrolidone with γ-butyrolactone with propylene glycol monobutyl ether with diisobutyl ketone, N-methyl-2-pyrrolidone with γ-butyrolactone Lactone with propylene glycol monobutyl ether with diisopropyl ether, N-methyl-2-pyrrolidone with γ-butyrolactone with propylene glycol monobutyl ether with diisobutylmethanol, N-methyl-2-pyrrolidone with γ-butyrolactone with dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone with propylene glycol monobutyl ether with dipropylene glycol dimethyl ether, N-ethyl-2-pyrrolidone with propylene glycol monobutyl ether with dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone with diethylene glycol diethyl ether with dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone with propylene glycol monobutyl ether with propylene glycol diacetate, N-ethyl-2-pyrrolidone with propylene glycol monobutyl ether with diisobutyl ketone, N-ethyl-2-pyrrolidone with γ-butyrolactone with diisobutyl ketone, N-ethyl-2-pyrrolidone with N,N-Dimethyllactamamine with diisobutyl ketone, N-methyl-2-pyrrolidone with ethylene glycol monobutyl ether and ethylene glycol monobutyl ether acetate, γ-butyrolactone with ethylene glycol monobutyl ether acetate and dipropylene glycol dimethyl ether, N-ethyl-2-pyrrolidone with ethylene glycol monobutyl ether acetate and propylene glycol dimethyl ether, N-methyl-2-pyrrolidone with 4-methyl-2-pentyl acetate and ethylene glycol monobutyl ether, N-ethyl-2-pyrrolidone with cyclohexyl acetate and diacetone alcohol, cyclohexanone with propylene glycol monomethyl ether, cyclopentanone with propylene glycol monomethyl ether, N-methyl-2-pyrrolidone with cyclohexanone and propylene glycol monomethyl ether, tetramethylurea with 4-hydroxy-4-methyl-2-pentanone Tetramethylurea with propylene glycol diacetate, N,N-dimethylpropionic acid with propylene glycol monobutyl ether, tetramethylurea with propylene glycol monobutyl ether, tetramethylurea with cyclohexanone with propylene glycol monomethyl ether, N,N-dimethylpropionic acid with propylene glycol monomethyl ether, N,N-dimethylpropionic acid with ethylene glycol monobutyl ether acetate, N,N-dimethylpropionic acid with ethylene glycol monobutyl ether, tetramethylurea with propylene glycol monomethyl ether, N,N-dimethylpropionic acid with cyclohexanone with diethylene glycol diethyl ether, N,N-diethylmethoxylamine with propylene glycol monomethyl ether, N,N-diethylmethoxylamine with 4-hydroxy-4-methyl-2-pentanone, N,N-diethylmethoxylamine with propylene glycol monomethyl ether, etc.

[0113] (Additive Components) The liquid crystal alignment agent of the present invention may also additionally contain components other than (A), (B), and organic solvents (hereinafter also referred to as additive components). Such additive components include, for example, crosslinking compounds, functional silane compounds, metal chelate compounds, curing accelerators, surfactants, antioxidants, sensitizers, preservatives, compounds for adjusting the dielectric constant and resistance of resin films, etc. The crosslinking compound is selected from at least one of the following groups: crosslinking compounds having at least one substituent selected from epoxy groups, oxacyclobutane groups, oxazoline structures, cyclic carbonate groups, capped isocyanate groups, hydroxyl groups, and alkoxy groups (c-1), and crosslinking compounds having polymerizable unsaturated groups (c-2).

[0114] Ideal specific examples of the above-mentioned crosslinking compounds (c-1) and (c-2) can be listed below. Compounds having epoxy groups 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-tetracyclooxypropyl-2,4-hexanediol, bisphenol A type epoxy resins such as EPIKOTE828 (manufactured by Mitsubishi Chemical Corporation), bisphenol F type epoxy resins such as EPIKOTE807 (manufactured by Mitsubishi Chemical Corporation), hydrogenated bisphenol A type epoxy resins such as YX-8000 (manufactured by Mitsubishi Chemical Corporation), and YX6... Epoxy resins containing a biphenyl backbone, such as 954BH30 (manufactured by Mitsubishi Chemical Corporation); phenol-formaldehyde varnish-type epoxy resins, such as EPPN-201 (manufactured by Nippon Kayaku Co., Ltd.); cresol-formaldehyde varnish-type epoxy resins (ortho, meta, para) such as EOCN-102S (manufactured by Nippon Kayaku Co., Ltd.); tetra(epoxypropoxymethyl)methane; N,N,N',N'-tetracyclooxypropyl-1,4-phenylenediamine; N,N,N',N'-tetracyclooxypropyl-2,2'-dimethyl-4,4'-diaminobiphenyl; 2,2-bis[4-(N,N-dicyclooxypropyl-4-aminophenoxy)phenyl]propane; N,N,N',N'-tetracyclooxypropyl Compounds consisting of tertiary nitrogen atoms and aromatic carbon atoms bonded together, such as -4,4'-diaminodiphenylmethane; N,N,N',N'-tetracyclooxypropyl-1,2-diaminocyclohexane, N,N,N',N'-tetracyclooxypropyl-1,3-diaminocyclohexane, N,N,N',N'-tetracyclooxypropyl-1,4-diaminocyclohexane, bis(N,N-dicyclooxypropyl-4-aminocyclohexyl)methane, bis(N,N-dicyclooxypropyl-2-methyl-4-aminocyclohexyl)methane, bis(N,N-dicyclooxypropyl-3-methyl-4-aminocyclohexyl)methane, 1,3-bis(N,N-dicyclooxypropylaminomethyl)cyclohexane, 1, Compounds of tertiary nitrogen atom system and aliphatic carbon atom bonded by 4-bis(N,N-dicyclooxypropylaminomethyl)cyclohexane, 1,3-bis(N,N-dicyclooxypropylaminomethyl)benzene, 1,4-bis(N,N-dicyclooxypropylaminomethyl)benzene, 1,3,5-tris(N,N-dicyclooxypropylaminomethyl)cyclohexane, 1,3,5-tris(N,N-dicyclooxypropylaminomethyl)benzene, etc.; isocyanurate compounds such as tricyclooxypropyl isocyanurate produced by Nissan Chemical Co., Ltd.; compounds described in paragraph

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

[0170] to

[0175] of WO2011 / 132751. Compounds having an acezoline group include, for example, compounds such as 2,2'-bis(2-acezoline), 2,2'-bis(4-methyl-2-acezoline), polymers and oligomers having an acezoline group such as EPOCROS (trade name, manufactured by Nippon Shokubai Co., Ltd.), and compounds described in paragraph

[0115] of Japanese Patent Application Publication No. 2007-286597; Compounds having cyclic carbonate groups include, for example, N,N,N',N'-tetratetra[(2-sideoxy-1,3-dioxolane-4-yl)methyl]-4,4'-diaminodiphenylmethane, N,N'-di[(2-sideoxy-1,3-dioxolane-4-yl)methyl]-1,3-phenylenediamine, and compounds described in paragraphs

[0025] to

[0030] and

[0032] of WO2011 / 155577; and compounds having terminal isocyanate groups include, for example, CORONATEAP STABLE. M, CORONATE2503, 2515, 2507, 2513, 2555, MILLIONATEMS-50 (all manufactured by Tosoh Corporation), TAKENATEB-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, B-882N (all manufactured by Mitsui Chemicals Corporation), compounds having two or more protected isocyanate groups as described in paragraphs

[0046] to

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

[0119] to

[0120] of WO2015 / 141598, etc.Compounds having hydroxyl and alkoxy groups include, for example, N,N,N',N'-tetra(2-hydroxyethyl)hexamethylenediamine, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethoxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)-1,1,1,3,3,3-hexafluoropropane, compounds described in paragraph

[0058] of Japanese Patent Application Publication No. WO2015 / 072554, Japanese Patent Application Publication No. 2016-118753, Japanese Patent Application Publication No. 2016-200798, and compounds described in WO2010 / 074269; Examples of crosslinkable compounds with polymerizable unsaturated groups include glycerol mono(meth)acrylate, glycerol di(meth)acrylate (a mixture of 1,2- and 1,3-dimethyl acrylates), glycerol tri(meth)acrylate, glycerol 1,3-diglyceric acid di(meth)acrylate, neopentyl tert-ol tri(meth)acrylate, diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, pentaethylene glycol mono(meth)acrylate, and hexaethylene glycol mono(meth)acrylate.

[0115] The content of crosslinking compounds (c-1) and (c-2) in the liquid crystal alignment agent of the present invention is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the total polymer components contained in the liquid crystal alignment agent, more preferably 0.1 to 20 parts by mass, and even more preferably 1 to 10 parts by mass.

[0116] Among the compounds mentioned above used to adjust the dielectric constant and resistance of the resin film, monoamines containing nitrogen atoms, such as 3-pyridinemethylamine, are examples. When using a monoamine containing nitrogen atoms, its content is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent, and more preferably 0.1 to 20 parts by mass.

[0117] Ideal specific examples of functional silane compounds 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, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane. Oxysilanes, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, 3-epoxypropoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-propenyloxypropyltrimethoxysilane, tris(3-trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, etc. When using functional silane compounds, it is preferable that their content is 0.1 to 30 parts by mass relative to 100 parts by mass of polymer components contained in the liquid crystal alignment agent, and more preferably 0.1 to 20 parts by mass.

[0118] 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 liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) can be appropriately selected by taking into account viscosity, volatility, etc., and is preferably in the range of 1 to 10% by mass.

[0119] The ideal range of solid component concentration depends on the method used when coating the liquid crystal alignment agent onto the substrate. For example, when using spin coating, a solid component concentration of 1.5 to 4.5% by mass is particularly preferred. When using printing, a solid component concentration of 3 to 9% by mass is preferable, thereby achieving a solution viscosity of 12 to 50 mPa·s. When using inkjet printing, a solid component concentration of 1 to 5% by mass is preferable, thereby achieving a solution viscosity 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.

[0120] The liquid crystal alignment agent described above can be effectively applied to various technical applications, such as liquid crystal alignment films (liquid crystal alignment films for phase difference films, scanning antennas, liquid crystal array antennas, or liquid crystal alignment films for transmission-scattering type liquid crystal dimming elements), protective films (e.g., protective films for color filters), spacer films, interlayer insulating films, anti-reflective films, wiring coating films, antistatic films, motor insulating films (gate insulating films for flexible displays), etc. [Liquid crystal alignment film and liquid crystal display element] By using the above-described liquid crystal alignment agent, a liquid crystal alignment film can be manufactured. Furthermore, the liquid crystal display element of the present invention includes a liquid crystal alignment film formed using the above-described liquid crystal alignment agent. The operating mode of the liquid crystal display element of this invention is not particularly limited, and it can be applied to various operating modes such as TN type, STN (Super Twisted Nematic) type, vertical alignment type (including VA-MVA type, VA-PVA type, etc.), in-plane switching type (IPS type, FFS type), optically compensated bending type (OCB type), etc.

[0121] The liquid crystal display element of the present invention can be manufactured, for example, by a method including the following steps (1) to (4), a method including steps (1) to (2) and (4), a method including steps (1) to (3), (4-2) and (4-4), or a method including steps (1) to (3), (4-3) and (4-4). <Step (1): Step of coating the liquid crystal alignment agent on the substrate> Step (1) is the step of coating the liquid crystal alignment agent of the present invention on the substrate. Specific examples of step (1) are as follows.

[0122] The liquid crystal alignment agent of the present invention is applied to one side of a substrate having a patterned transparent conductive film using a suitable coating method such as roll coating, spin coating, printing, or inkjet coating. Here, the substrate is not particularly limited to any substrate with high transparency; glass substrates, silicon nitride substrates, acrylic substrates, polycarbonate substrates, and other plastic substrates can also be used. Furthermore, for reflective liquid crystal display elements, if only a single-sided substrate is used, an opaque material such as a silicon wafer can be used; in this case, the electrodes can also be made of light-reflecting materials such as aluminum. Moreover, when manufacturing 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 a facing substrate without electrodes are used.

[0123] Methods for coating liquid crystal alignment agents onto a substrate and forming a film include screen printing, offset printing, flexographic printing, inkjet printing, and spraying. Among these, inkjet printing is an ideal coating and film forming method. <Step (2): The step of calcining the coated liquid crystal alignment agent> Step (2) is the step of calcining the liquid crystal alignment agent coated on the substrate to form a film. The specific example of step (2) is as follows.

[0124] After coating the liquid crystal alignment agent onto the substrate in step (1), a heating method such as a hot plate, a thermally circulating oven, or an IR (infrared) oven can be used to evaporate the solvent or perform thermal amide formation of polyamide or polyamide ester. The drying and calcination steps after coating the liquid crystal alignment agent of the present invention can be performed at any temperature and for any time, and can be repeated multiple times. The calcination temperature of the liquid crystal alignment agent can be, for example, 40~180°C. From the viewpoint of reducing processing, it can also be performed at 40~150°C. The calcination time is not particularly limited, and can be 1~10 minutes or 1~5 minutes. When performing thermal amide formation of polyamide, a calcination step at a temperature range of, for example, 150~300°C or 150~250°C can be added after the above steps. The calcination time is not particularly limited; examples include calcination times of 5 to 40 minutes or 5 to 30 minutes.

[0125] If the film after calcination is too thin, the reliability of the liquid crystal display element will be reduced. Therefore, 5~300nm is more ideal, and 10~200nm is even more ideal.

[0126] <Step (3): Step of aligning the film obtained in step (2)> Step (3) is a step of aligning the film obtained in step (2) as appropriate. That is, for horizontally aligned liquid crystal display elements such as IPS or FFS, the coating is subjected to alignment capability imparting treatment. On the other hand, for vertically aligned liquid crystal display elements such as VA or PSA, the formed coating can be used directly as a liquid crystal alignment film, but alignment capability imparting treatment can also be performed on the coating. Alignment treatment methods for liquid crystal alignment films include rubbing treatment and photoalignment treatment. For photoalignment treatment, the surface of the above-mentioned film is irradiated with radiation deflected in a certain direction, and, as appropriate, it is preferably heated at a temperature of 150~250°C to impart liquid crystal alignment properties (also known as liquid crystal alignment capability). The radiation can be ultraviolet light or visible light with a wavelength of 100~800nm. Among them, ultraviolet light with a wavelength of 100~400nm is preferred, and more preferably 200~400nm is preferred.

[0127] The radiation dose is preferably 1 to 10,000 mJ / cm², with 100 to 5,000 mJ / cm² being more preferred. Furthermore, during radiation irradiation, to improve liquid crystal alignment, the substrate having the film can be heated at 50 to 250°C while being irradiated. The liquid crystal alignment film prepared in this manner enables the liquid crystal molecules to be stably aligned in a specific direction.

[0128] Alternatively, the liquid crystal alignment film irradiated with polarized radiation as described above may be subjected to contact treatment with water or solvent, or the liquid crystal alignment film irradiated with radiation may be subjected to heat treatment.

[0129] The solvent used in the above-mentioned contact treatment is not particularly limited as long as it can dissolve the decomposition products generated from the film due to radiation irradiation. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl ceroxysulfate, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate, etc. The solvent may be one type or a combination of two or more.

[0130] The temperature for heat treatment of the above-mentioned irradiated coating is preferably 50~300℃, and even more preferably 120~250℃. The heat treatment time is preferably 1~30 minutes. <Step (4): Steps for fabricating liquid crystal cells> Prepare two substrates on which liquid crystal alignment films have been formed as described above, and place liquid crystal between the two opposing substrates. Specifically, the following two methods can be listed.

[0131] In the first method, two substrates are first arranged facing each other with their respective liquid crystal alignment films facing each other and separated by a cell gap. Then, the two substrates are bonded together at their periphery using a sealant, and liquid crystal composition is injected into the cell gaps separated by the substrate surface and the sealant. After the liquid crystal composition contacts the film surface, the injection hole is sealed.

[0132] There are no special limitations on the above-mentioned liquid crystal composition. Various liquid crystal compositions containing at least one liquid crystal compound (liquid crystal molecule) and having positive or negative dielectric constant anisotropy can be used. Furthermore, liquid crystal compositions with positive dielectric constant anisotropy are also referred to as positive liquid crystals, and liquid crystal compositions with negative dielectric constant anisotropy are also referred to as negative liquid crystals. The above-mentioned liquid crystal composition may also contain liquid crystal compounds having fluorine atoms, hydroxyl groups, amino groups, groups containing fluorine atoms (e.g., trifluoromethyl), cyano groups, alkyl groups, alkoxy groups, alkenyl groups, isothiocyanate groups, heterocyclic groups, cycloalkanes, cycloalkenes, steroid skeletons, benzene rings, or naphthyl rings. It may also contain compounds having two or more rigid sites (liquid crystal proto-skeletons) exhibiting liquid crystal properties within the molecule (e.g., rigid two biphenyl structures, or biphenyl structures linked by alkyl groups to form a double liquid crystal proto-skeleton, etc.). The liquid crystal composition may be a nematic liquid crystal composition, a lamellar liquid crystal composition, or a cholesterol liquid crystal composition. Furthermore, considering the need for improved liquid crystal alignment, additives can be added to the aforementioned liquid crystal composition. Examples of such additives include photopolymerizable monomers such as compounds with polymerizable groups; optically active compounds (e.g., Merck S-811); antioxidants; ultraviolet absorbers; pigments; defoamers; polymerization initiators; or polymerization inhibitors. Positive liquid crystals include Merck's ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, and MLC-7081. Negative liquid crystals include, for example, Merck's MLC-6608, MLC-6609, MLC-6610, MLC-6882, MLC-6886, MLC-7026, MLC-7026-000, MLC-7026-100, and MLC-7029. Furthermore, in PSA mode, liquid crystals containing polymerizable compounds can be exemplified by Merck's MLC-3023.

[0133] Furthermore, the second method is called the ODF (One Drop Fill) method. A UV-curable sealant, for example, is applied to a predetermined location on one of the two substrates on which the liquid crystal alignment film has been formed. Then, liquid crystal composition is dropped onto predetermined locations on the surface of the liquid crystal alignment film. Next, the other substrate is bonded with the liquid crystal alignment films facing each other, pressing the liquid crystal composition onto the entire surface of the substrate so that it contacts the film surface. Then, the entire surface of the substrate is irradiated with UV light to harden the sealant. When using either method, it is advisable to further heat until the liquid crystal composition reaches a temperature of isotropic phase, and then slowly cool it to room temperature to remove the flow alignment during liquid crystal filling.

[0134] Furthermore, when the coating is subjected to friction treatment, the two substrates are arranged facing each other with the friction directions of each coating at a predetermined angle, such as orthogonal or antiparallel.

[0135] For sealants, epoxy resins containing alumina spheres can be used as hardeners and spacers. Nematic liquid crystals and smectic liquid crystals can be used, with nematic liquid crystals being preferred. Examples of suitable liquid crystals include fluorine-based liquid crystals, cyano-based liquid crystals, Schiff base-based liquid crystals, azoxy-based liquid crystals, biphenyl-based liquid crystals, phenylcyclohexane-based liquid crystals, ester-based liquid crystals, terphenyl-based liquid crystals, biphenylcyclohexane-based liquid crystals, pyrimidine-based liquid crystals, dialkyl-based liquid crystals, dicyclooctane-based liquid crystals, and cubane-based liquid crystals. Furthermore, cholesterol liquid crystals such as cholesterol chloride, cholesteryl nonanoate, and cholesteryl carbonate; chiral reagents sold under trade names "C-15" and "CB-15" (manufactured by Merck); and strongly dielectric liquid crystals such as decoxybenzyl-p-amino-2-methylbutyl cinnamate can also be added to these liquid crystals before use. In addition, various substances as disclosed in Japanese Patent Application Publication No. 2019-132952 may be used.

[0136] The above-mentioned liquid crystals are generally prepared by mixing several liquid crystals in a manner that meets the desired physical properties according to the intended use (hereinafter, the liquid crystal composition obtained by mixing multiple liquid crystals is also referred to as mixed liquid crystal).

[0137] Among these, it is preferable to use fluorine-based mixed liquid crystals commonly used in current liquid crystal display devices. Here, fluorine-based mixed liquid crystals in this specification refer to mixed liquid crystals containing one or more fluorine-based liquid crystals, and cyano-based mixed liquid crystals refer to mixed liquid crystals containing one or more cyano-based liquid crystals.

[0138] The aforementioned mixed liquid crystals are generally known and commercially available. For example, fluorine-based mixed liquid crystals, specifically liquid crystals with a positive dielectric constant anisotropy Δε (also known as positive liquid crystals), are sold under the trade name ZLI-4792, and liquid crystals with a negative dielectric constant anisotropy Δε (also known as negative liquid crystals) are sold under the trade name MLC-6608 by Merck. Furthermore, in cyano-based mixed liquid crystals, positive liquid crystals are sold under the trade name JC-5066XX by CHISSO Petrochemicals. In this invention, a liquid crystal alignment film suitable for use in liquid crystal display elements employing negative liquid crystals is provided, as well as a liquid crystal alignment agent applied to the liquid crystal alignment film.

[0139] The liquid crystal alignment agent of the present invention is also suitable for use in liquid crystal display elements (PSA type liquid crystal display elements) that have a liquid crystal layer between a pair of substrates having electrodes, and a liquid crystal composition containing a polymerizable compound that is polymerized by at least one of active energy rays and heat disposed between the pair of substrates, and polymerize the polymerizable compound by applying voltage between the electrodes and irradiating with active energy rays and heating.

[0140] Furthermore, the liquid crystal alignment agent of the present invention can also be used in a liquid crystal display element (SC-PVA type liquid crystal display element) manufactured by applying a voltage between the electrodes, wherein a liquid crystal layer is provided between the two substrates, and a liquid crystal alignment film containing polymerizable groups that are polymerized by at least one of active energy rays and heat is disposed between the two substrates. <Step (4-2): Case of PSA type liquid crystal display element> Except for injecting or dropping a point containing a liquid crystal composition containing a polymerizable compound, it is performed in the same way as (4) above. Examples of polymerizable compounds include polymerizable compounds having one or more polymerizable unsaturated groups such as acrylate groups and methacrylate groups in the molecule. <Step (4-3): Case of SC-PVA type liquid crystal display element> It is also possible to manufacture a liquid crystal display element by irradiating ultraviolet light as described later after performing the same steps as (4) above. Following this method, similar to manufacturing the aforementioned PSA-type liquid crystal display element, a liquid crystal display element with excellent response speed can be obtained with a low amount of light irradiation. The compound having a polymerizable group can be a compound having one or more polymerizable unsaturated groups as described above within its molecule, and its content relative to 100 parts by mass of the total polymer component is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass. Furthermore, the aforementioned polymerizable group can be present in the polymer used as a liquid crystal alignment agent. Examples of such polymers include those obtained by using a diamine component containing a diamine terminally having the aforementioned photopolymerizable group in the reaction. <Step (4-4): Step of irradiating with ultraviolet light> The liquid crystal cell is irradiated with light while applying a voltage between the conductive films on the substrate obtained in (4-2) or (4-3) above. Here, the applied voltage can be, for example, DC or AC of 5 to 50V. Furthermore, the irradiation light can be ultraviolet light or visible light containing wavelengths of, for example, 150-800 nm, but ultraviolet light containing wavelengths of 300-400 nm is preferred. The light source can be, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonant lamp, a xenon lamp, or an excimer laser. The light intensity is preferably 1,000-200,000 J / m², more preferably 1,000-100,000 J / m².

[0141] Furthermore, a polarizing plate can be attached to the outer surface of the liquid crystal cell as needed to obtain a liquid crystal display element. Examples of polarizing plates attached to the outer surface of the liquid crystal cell include: a polarizing film called "H film" which is oriented by extending polyvinyl alcohol on one side and absorbing iodine on the other side, which is sandwiched with a cellulose acetate protective film; or a polarizing plate composed of the H film itself.

[0142] Furthermore, a polarizing plate can be attached to the outer surface of the liquid crystal cell as needed to obtain a liquid crystal display element. Examples of polarizing plates attached to the outer surface of the liquid crystal cell include: a polarizing film called "H film" which is oriented by extending polyvinyl alcohol on one side and absorbing iodine on the other side, which is sandwiched with a cellulose acetate protective film; or a polarizing plate composed of the H film itself.

[0143] The comb electrode substrate used in IPS mode, namely the IPS substrate, has: a substrate, and a plurality of linear electrodes formed on the substrate and arranged in a comb shape; and a liquid crystal alignment film formed on the substrate in such a way as to cover the linear electrodes.

[0144] Furthermore, the comb electrode substrate used in the FFS mode, namely the FFS substrate, 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 arranged in a comb-like shape; and a liquid crystal alignment film formed on the insulating film in such a way as to cover the linear electrodes.

[0145] FIG1 is a schematic cross-sectional view showing an example of the transverse electric field liquid crystal display element of the present invention, which is an example of an IPS mode liquid crystal display element.

[0146] In the transverse electric field liquid crystal display element 1 illustrated in FIG1, liquid crystal 3 is sandwiched between a comb electrode substrate 2 having a liquid crystal alignment film 2c and a counter substrate 4 having a liquid crystal alignment film 4a. The comb electrode substrate 2 has: a substrate 2a; a plurality of linear electrodes 2b formed and arranged in a comb-like shape on the substrate 2a; and a liquid crystal alignment film 2c formed on the substrate 2a in such a way as to cover the linear electrodes 2b. The counter substrate 4 has: 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 the liquid crystal alignment film of the present invention.

[0147] In this horizontal electric field liquid crystal display element 1, if a voltage is applied to the linear electrode 2b, an electric field will be generated between the linear electrodes 2b as shown by the electric field line L.

[0148] FIG2 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.

[0149] In the transverse electric field liquid crystal display element 1 illustrated in FIG2, liquid crystal 3 is sandwiched between a comb electrode substrate 2 having a liquid crystal alignment film 2h and a counter substrate 4 having a liquid crystal alignment film 4a. The comb electrode substrate 2 has: 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 formed on the insulating film 2f and arranged in a comb-like shape; and a liquid crystal alignment film 2h formed on the insulating film 2f in such a way as to cover the linear electrodes 2g. The counter substrate 4 has: 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 the liquid crystal alignment film of the present invention.

[0150] In this horizontal electric field liquid crystal display element 1, if a voltage is applied to the surface electrode 2e and the linear electrode 2g, an electric field will be generated between the surface electrode 2e and the linear electrode 2g as shown by the electric field line L.

[0151] The liquid crystal alignment film of the present invention, in addition to the liquid crystal alignment film for the above-mentioned uses, can also be used in various other applications, such as: liquid crystal alignment film for phase difference films, liquid crystal alignment film for scanning antennas, liquid crystal array antennas, or liquid crystal alignment film for transmission and scattering type liquid crystal dimming elements. Furthermore, it can also be used in applications other than liquid crystal alignment films, such as: protective films (e.g., protective films for color filters), spacer films, interlayer insulating films, anti-reflective films, wiring coating films, antistatic films, and motor insulating films (gate insulating films for flexible displays).

[0152] The liquid crystal display element of the present invention can be effectively applied in various devices, such as: clocks, portable game consoles, word processors, laptops, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various screens, LCD TVs, information displays, and other display devices. [Example]

[0153] The following specific description is given with reference to examples of the present invention, but the present invention is not limited to these examples. Furthermore, the abbreviations for compounds and solvents are as follows: (Organic solvents) NMP: N-methyl-2-pyrrolidone; GBL: γ-butyrolactone; BCS: butylceroxose.

[0154] (Diamine) [Chemical 22] The diamines of formula (DA-1), (DA-2) and (DA-5) are included in the range of diamines represented by formula (dAL). The diamine of formula (DA-3) is included in the range of diamines represented by formula (dn).

[0155] (Tetracarboxylic dianhydride) [Chemical 23] The tetracarboxylic dianhydride of formula (CA-1) is included in the range of tetracarboxylic dianhydrides represented by formula (Tc). The tetracarboxylic dianhydrides of formulas (CA-2) and (CA-4) are included in the range of tetracarboxylic dianhydrides represented by formula (Tf).

[0156] (Additive) AD-1: 3-Epoxypropoxypropyltriethoxysilane

[0157] [Chemical 24]

[0158] (Viscosity Measurement) In the synthesis example, the viscosity of the polymer solution was measured using a TVE-22H type E viscometer (manufactured by Toki Sangyo Co., Ltd.) with a sample volume of 1.1 mL, a conical rotor TE-1 (1°34', R24), and a temperature of 25°C. <Synthesis of Polyamide> (Synthesis Example 1) 3.15 g of DA-1 (11.0 mmol) was measured into a 100 mL round-bottom flask equipped with a stirring device and a nitrogen inlet tube. 28.4 g of NMP was added, and the solution was dissolved by stirring while introducing nitrogen. While stirring this diamine solution under water cooling, 2.37 g of CA-1 (10.6 mmol) was added, followed by 11.6 g of NMP. The solution was stirred at 40°C for 3 hours under nitrogen to obtain a polyamide solution (viscosity: 550 mPa·s) PAA-A1. (Synthesis Example 2) 3.66 g of DA-2 (15.0 mmol) and 2.99 g of DA-3 (15.0 mmol) were measured into a 100 mL round-bottom flask equipped with a stirrer and a nitrogen inlet tube. 59.9 g of NMP was added, and the solution was dissolved by stirring while introducing nitrogen. While stirring this diamine solution under water cooling, 5.63 g of CA-2 (22.5 mmol) was added, followed by 9.7 g of NMP. The mixture was stirred at 50°C under nitrogen for 2 hours. Then, 1.90 g of CA-3 (6.45 mmol) and 10.8 g of NMP were added. The mixture was stirred at 50°C under nitrogen for 15 hours to obtain a polyacrylic acid solution (viscosity: 515 mPa·s) PAA-B1. (Synthesis Example 3) 1.83 g of DA-2 (7.50 mmol), 0.540 g of DA-4 (5.00 mmol), 2.40 g of DA-5 (7.50 mmol), and 1.99 g of DA-6 (5.00 mmol) were measured into a 100 mL flask equipped with a stirrer and a nitrogen inlet tube. 77.8 g of NMP was added, and the solution was dissolved by stirring while introducing nitrogen. While stirring this diamine solution under water cooling, 5.38 g of CA-1 (24.0 mmol) was added, followed by 11.3 g of NMP. The mixture was stirred at 40°C under nitrogen for 15 hours to obtain a polyacrylic acid solution (viscosity: 410 mPa·s) PAA-A2. (Synthesis Example 4) Measure 6.97 g of DA-3 (35.0 mmol) and 6.94 g of DA-7 (35.0 mmol) into a 200 mL flask equipped with a stirrer and a nitrogen inlet tube. Add 102 g of NMP and stir while introducing nitrogen gas to dissolve the diamine solution. While stirring this diamine solution under water cooling, add 8.76 g of CA-2 (35.0 mmol) and then add 26.4 g of NMP. Stir at 50°C for 2 hours under nitrogen atmosphere.Furthermore, 9.54 g of CA-3 (32.4 mmol) and 53.7 g of NMP were added, and the mixture was stirred at 50°C for 15 hours under nitrogen atmosphere to obtain a polyacrylic acid solution (viscosity: 400 mPa・s) PAA-B2.

[0159] (Synthesis Example 5) 2.49 g of DA-2 (10.2 mmol) and 4.74 g of DA-3 (23.8 mmol) were measured into a 100 mL round-bottom flask equipped with a stirrer and a nitrogen inlet tube. 58.5 g of NMP was added, and the solution was dissolved by stirring while introducing nitrogen. While stirring this diamine solution under water cooling, 3.81 g of CA-4 (17.0 mmol) was added, followed by 4.1 g of NMP. The mixture was stirred at 50°C under nitrogen for 2 hours. Then, 4.35 g of CA-3 (14.8 mmol) and 24.7 g of NMP were added. The mixture was stirred at 50°C under nitrogen for 15 hours to obtain a polyacrylic acid solution (viscosity: 298 mPa·s) PAA-B3. The types and amounts of the diamine components and tetracarboxylic acid derivative components used in Synthesis Examples 1-5 are summarized in Table 1. In Table 1, the values ​​in parentheses represent the amount of monomer used relative to the total 100 moles of each component (moles).

[0160] [Table 1] Synthesis example polymer name Polymer types Tetracarboxylic acid derivative components diamine component 1 PAA-A1 polyamide CA-1(100) DA-1(100) 2 PAA-B1 polyamide CA-2(77) CA-3(23) DA-2(50) DA-3(50) 3 PAA-A2 polyamide CA-1(100) DA-2(30) DA-4(20) DA-5(30) DA-6(20) 4 PAA-B2 polyamide CA-2(52) CA-3(48) DA-3(50) DA-7(50) 5 PAA-B3 polyamide CA-3(47) CA-4(53) DA-2(30) DA-3(70)

[0161] <Preparation of Liquid Crystal Orientation Agent> (Examples 1-3 and Comparative Example 1) The polyamide solutions obtained in Synthesis Examples 1-5 were weighed to form a combination of the compositions of polymer 1 and polymer 2 as shown in the table below, and they were mixed. Then, NMP, GBL, BCS, a GBL solution containing 1% by weight of AD-1, and an NMP solution containing 10% by weight of AD-2 were added while stirring to form the compositions shown in Table 2 below, and stirred at room temperature for 2 hours to obtain the liquid crystal orientation agents (1)-(3) of Examples 1-3 and the liquid crystal orientation agent (R1) of Comparative Example 1. The specifications of the liquid crystal orientation agents obtained in Examples 1-3 and Comparative Example 1 are shown in Table 2.

[0162] [Table 2] Liquid crystal alignment agent Polymer 1 Polymer 2 organic solvents Additive solution NMP GBL BCS AD-1 AD-2 Example 1 (1) PAA-A1 1.50g PAA-B1 2.80g 5.40g 5.40g 4.00g 0.600g 0.300g Example 2 (2) PAA-A2 1.50g PAA-B1 2.80g 5.40g 5.40g 4.00g 0.600g 0.300g Example 3 (3) PAA-A1 1.50g PAA-B3 2.80g 5.40g 5.40g 4.00g 0.600g 0.300g Comparative Example 1 (R1) PAA-A2 1.50g PAA-B2 2.80g 5.40g 5.40g 4.00g 0.600g 0.300g

[0163] Using the liquid crystal alignment agents obtained above, an FFS-mode liquid crystal cell was fabricated according to the procedure shown below, and the pretilt angle and the retention characteristics due to long-term AC drive were evaluated. [Fabrication of FFS-mode liquid crystal cell] First, a glass substrate with an auxiliary electrode of size 30mm × 35mm and a thickness of 0.7mm was prepared. An IZO electrode with a full-page pattern constituting the first layer counter electrode was formed on the substrate. A SiN (silicon nitride) film formed by CVD (chemical vapor deposition) was formed on the first layer counter electrode. The thickness of the second layer SiN film was 500nm, which served as an interlayer insulating film. On the second layer SiN film, a comb-shaped pixel electrode formed by patterning the third layer IZO film was disposed, forming two pixels, the first pixel and the second pixel, each pixel having a size of 10mm in length and 5mm in width. At this point, the opposing electrode of the first layer and the pixel electrode of the third layer are electrically insulated by the SiN film of the second layer. The pixel electrode of the third layer has a comb-shaped structure in which multiple 3μm wide electrode elements with an inner angle of 160° are arranged in parallel at 6μm intervals. Each pixel has a first region and a second region, with the line connecting the bent portions of the multiple electrode elements as the boundary.

[0164] Then, the liquid crystal alignment agents (1) to (3) and (R1) obtained in Examples 1 to 3 and Comparative Example 1 were filtered through a filter with a pore size of 1.0 μm and spin-coated onto the surface of the prepared electrode substrate (first glass substrate) and the surface of the glass substrate (second glass substrate) on which an ITO film has been formed on the back and which has columnar spacers with a height of 4 μm. Then, after drying on a hot plate at 80°C for 2 minutes, the substrate was calcined at 230°C for 20 minutes to obtain a polyimide film with a thickness of 60 nm on each substrate. The liquid crystal alignment film was rubbed with a cloth (roller diameter: 140 mm, roller speed: 1000 rpm, moving speed: 30 mm / sec, push length: 0.3 mm), then ultrasonically irradiated in pure water for 1 minute to clean it, and after removing water droplets by blowing air, it was dried at 80°C for 10 minutes to obtain a substrate with a liquid crystal alignment film. Using the two substrates with liquid crystal alignment films described above, they were combined in an antiparallel manner with their respective friction directions, retaining the liquid crystal injection port and sealing the surrounding area to create a vacant cell with a cell gap of 4μm. This vacant cell was then vacuum-injected with liquid crystal MLC-7026-100 (manufactured by Merck, a negative liquid crystal) at room temperature, and the injection port was sealed to create an antiparallel aligned liquid crystal cell. The obtained liquid crystal cell constituted an FFS mode liquid crystal display element. The liquid crystal cell was then heated at 120°C for 1 hour and placed at 23°C overnight before being used in the following evaluations. <Evaluation of Pretilt Angle> The pretilt angle of the above liquid crystal cell was evaluated using an AxoScan Mueller matrix polarimeter manufactured by OPTOMETRICS. The viewing angle characteristic was considered better with a lower pretilt angle. Specifically, a pretilt angle less than 2.0° was defined as "good," and a pretilt angle greater than 2.0° was defined as "poor." <Evaluation of Image Retention Characteristics Due to Long-Term AC Drive> Using the above-mentioned liquid crystal cell, an AC voltage of ±5.5V was applied at a frequency of 30Hz for 72 hours under high-brightness backlight (30,000 cd / m²). Afterwards, the pixel electrode and the opposing electrode of the liquid crystal cell were short-circuited.

[0165] After being placed at 23°C for one night, the liquid crystal cell is positioned between two polarizing plates with their polarization axes orthogonally aligned. The backlight is then turned on without any applied voltage, and the arrangement angle of the liquid crystal cell is adjusted to minimize the transmitted light brightness. Furthermore, the rotation angle Δθ1 is calculated and defined as the angle at which the liquid crystal cell rotates from the darkest angle in the second region of the first pixel to the darkest angle in the first region. Similarly, the angle Δθ2 is calculated by comparing the second and first regions of the second pixel. The average value of these Δθ1 and Δθ2 is defined as the angle Δθ of the liquid crystal cell. The smaller this value, the better the liquid crystal alignment is defined and rated. Specifically, when this angle Δθ is less than 0.4°, the image retention characteristics are excellent, i.e., defined and rated as "good"; when it is 0.4° or greater, it is defined and rated as "poor".

[0166] The evaluation results of liquid crystal display elements using the liquid crystal alignment agents of Examples 1 to 3 and Comparative Example 1 are shown in Table 3 below.

[0167] [Table 3] Liquid crystal alignment agent Polymer 1 Polymer 2 Pre-tilt angle (˚) Δθ(°) Example 1 (1) PAA-A1 PAA-B1 1.8 (Good) 0.18 (Good) Example 2 (2) PAA-A2 PAA-B1 1.9 (Good) 0.22 (Good) Example 3 (3) PAA-A1 PAA-B3 1.8 (Good) 0.20 (Good) Comparative Example 1 (R1) PAA-A2 PAA-B2 2.4 (Poor) 0.41 (Poor)

[0168] As shown in the table above, the liquid crystal display element using the liquid crystal alignment agent of Comparative Example 1 exhibits poor pretilt angle and image retention characteristics. In contrast, the liquid crystal display element using the liquid crystal alignment agent of the present invention in Examples 1-3 exhibits good pretilt angle and image retention characteristics. Therefore, it can be concluded that the liquid crystal display element using the liquid crystal alignment agent of the present invention has a small pretilt angle and good image retention characteristics.

[0169] Furthermore, the entire contents of the specification, scope of the application, drawings and abstract of Japanese Patent Application No. 2021-115167, filed on July 12, 2021, are hereby incorporated and used as disclosures in the specification of this invention. [Simplified Explanation of the Diagram]

[0024] FIG1 shows a schematic cross-sectional view of one example of the horizontal electric field liquid crystal display element of the present invention. FIG2 shows a schematic cross-sectional view of another example of the horizontal electric field liquid crystal display element of the present invention.

Claims

1. A liquid crystal alignment agent, characterized by comprising the following components (A) and (B): Component (A): Polymer (A), which is at least one of the following groups: a polyimide precursor, which is a product of the reaction of a tetracarboxylic acid dianhydride represented by formula (Tc) comprising 100 mol% of all tetracarboxylic acid derivative components and a diamine represented by formula (dAL) comprising 60 mol% or more of all diamine components; and a polyimide composed of a polyimide derivative of the polyimide precursor. (B) Composition: Polymer (B) is selected from at least one of the following groups: a tetracarboxylic acid derivative component containing a tetracarboxylic acid dianhydride of formula (Tf) at a content of 5 mol% or more of all tetracarboxylic acid derivative components; a diamine of formula (dAL) containing a diamine of formula (dn) where n is an integer from 2 to 5 in the group "*11-(CH2)nO-*12"; and a polyimide of a polyimide component that is a amide of the polyimide precursor; R11 to R14 each independently represent 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; and at least one of R11 to R14 represents a group other than a hydrogen atom as defined above. A represents the group "*11-(CH2)nO-*12", where, *11 represents an atomic bond with an oxygen atom or an atomic bond with a carbon atom constituting a benzene ring; *12 represents an atomic bond; n is an integer from 1 to 5; any hydrogen atom of the benzene ring bonded to an NH2 group can also be replaced by a monovalent group; Xf is a tetravalent organic group with an alicyclic structure of 5 or more members; Y represents a heterocyclic group selected from nitrogen-containing atoms and a group "*21-NR-*22", where *21 and *22 represent atomic bonds with carbon atoms constituting an aromatic ring, but 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, and the monovalent organic group is a divalent organic group with a nitrogen-containing structure in the group consisting of an amino group represented by ", which is a group of carbon atoms other than carbonyl carbons bonded to nitrogen atoms".

2. The liquid crystal alignment agent as claimed in claim 1, wherein, In the polymer (A), the A in the formula (dAL) is a divalent organic group with 1 to 18 carbon atoms.

3. The liquid crystal alignment agent as requested in item 1 or 2, wherein, The content of the diamine represented by formula (dAL) in the constituent components of the polymer (B) is 5 to 80 moles of all diamine components used in the manufacture of the polymer (B).

4. The liquid crystal alignment agent as requested in item 1 or 2, wherein, The content of the diamine represented by the above formula (dn) in the constituent components of the polymer (B) is 20 to 95 moles of all diamine components used in the manufacture of the polymer (B).

5. The liquid crystal alignment agent as requested in item 1 or 2, wherein, In this formula (dAL), *11 represents the atomic bond formed by the oxygen atom.

6. The liquid crystal alignment agent as requested in item 1 or 2, wherein, The diamine represented by formula (dAL) in the constituent components of polymer (A) is a diamine represented by formulas (dAL-1) to (dAL-9).

7. The liquid crystal alignment agent as claimed in claim 1 or 2, wherein, The diamine represented by formula (dn) is selected from at least one diamine in the group consisting of 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, and diamines represented by formulas (dn-1) to (dn-3). In formula (dn-1), m1 and m1' are each independently integers of 1 to 2, n1 is an integer of 1 to 3, and R1 is synonymous with the R in the amino group represented by "*21-NR-*22" in formula (dn). When there are multiple R1 and m1', the multiple R1 and m1' can be the same or different. In formula (dn-2), X2 represents a monovalent nitrogen-containing heterocyclic group, n1 is an integer from 1 to 2, n2 is an integer satisfying n1+n2=2, L1 and L2 each independently represent a single bond, -CO-, a alkyl group with 1 to 6 carbon atoms, or a divalent organic group in which -O- or -CO- is inserted between or at the end of the carbon-carbon bond of the alkyl group with 1 to 6 carbon atoms and is bonded to the nitrogen atom by a carbon atom, R represents a hydrogen atom or a methyl group. When there are multiple X2, L2, and R, the multiple X2, L2, and R can be the same or different. In formula (dn-3), X3 represents a divalent group with a nitrogen-containing heterocyclic ring, Ar3 represents a divalent aromatic cyclic group or a divalent nitrogen-containing saturated heterocyclic group; any hydrogen atom of the aromatic cyclic group and the nitrogen-containing saturated heterocyclic group can also be replaced by a monovalent group. L3 represents a single bond, -(CH2)n-, -NR'-, -(CH2)n-NR'-, -O-, -NR'-CO-, -CO-NR'-, -O-CO-, or -CO-O-, R' represents a hydrogen atom, methyl, or tert-butoxycarbonyl, n is an integer from 1 to 6, m3 and m3' are each an integer from 0 to 2, and either m3 or m3' is an integer greater than 1. When there are multiple Ar3 and L3, the multiple Ar3 and L3 can be the same or different, but the NH2 groups at both ends of formula (dn-3) are bonded to the carbon atoms that constitute the aromatic ring.

8. The liquid crystal alignment agent as claimed in claim 7, wherein, The diamine represented by formulas (dn-1) to (dn-3) is selected from the diamines represented by formulas (Dp-1) to (Dp-6) and the diamines represented by formulas (z-1) to (z-14).

9. The liquid crystal alignment agent as claimed in claim 1 or 2, wherein, The Xf series of formula (Tf) represents any of the four-valent organic groups in formulas (Xf-1) to (Xf-17), where * represents an atomic bond.

10. The liquid crystal alignment agent as claimed in claim 1 or 2, wherein, The ratio of component (A) to component (B), calculated as the mass ratio of [component (A)] to [component (B)], is 10 / 90 to 90 / 10.

11. The liquid crystal alignment agent as claimed in claim 1 or 2, wherein, The liquid crystal alignment agent further contains at least one additive component selected from the group consisting of crosslinking compounds, functional silane compounds, metal chelate compounds, curing accelerators, surfactants, antioxidants, sensitizers, preservatives, and compounds used to adjust the dielectric constant and resistance of the resin film. The crosslinking compound is selected from the group consisting of at least one crosslinking compound (c-1) having at least one substituent selected from epoxy group, oxacyclobutane group, oxazoline structure, cyclic carbonate group, terminal isocyanate group, hydroxyl group, and alkoxy group, and a crosslinking compound (c-2) having a polymerizable unsaturated group.

12. A liquid crystal alignment film formed using a liquid crystal alignment agent as claimed in any one of claims 1 to 11.

13. A liquid crystal display element comprising a liquid crystal alignment film as claimed in claim 12.

14. A method for manufacturing a liquid crystal display element, comprising the following steps (1) to (3): Step (1): applying a liquid crystal alignment agent as claimed in any one of claims 1 to 11 onto a substrate; Step (2): calcining the applied liquid crystal alignment agent to obtain a film; Step (3): performing alignment treatment on the film obtained in step (2).

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