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

Abstract

Provided is a liquid crystal alignment film that suppresses AC afterimage even when the amount of light irradiated during alignment processing using a photo-alignment method is small. Also provided is a liquid crystal alignment film capable of reducing unevenness (unevenness) of the twist angle of liquid crystals in the liquid crystal alignment film plane. A liquid crystal aligning agent containing at least one polymer (P) selected from the group consisting of polyimide precursors obtained using tetracarboxylic acid components and diamine components and polyimides that are imides of the polyimide precursors, the tetracarboxylic acid component includes at least one selected from the group consisting of tetracarboxylic acid dianhydrides represented by formula (1) and derivatives thereof, and the diamine component includes a diamine represented by formula (2). # imgabs0 # (the meaning of each symbol in the formula is as defined in the description).

Description

Technical Field

[0001] The present invention relates to a liquid crystal aligning agent, a liquid crystal alignment film, and a liquid crystal display element. Background Art

[0002] Liquid crystal display elements are widely used as display units for personal computers, mobile phones, smartphones, televisions, and the like. A liquid crystal display element includes, for example: a liquid crystal layer sandwiched between an element substrate and a color filter substrate; a pixel electrode and a common electrode for applying an electric field to the liquid crystal layer; a liquid crystal alignment film for controlling the liquid crystal alignment of liquid crystal molecules in the liquid crystal layer; a thin film transistor (TFT: Thin Film Transistor) for switching an electric signal supplied to the pixel electrode; and the like. As driving methods for liquid crystal molecules, known are longitudinal electric field methods such as TN (Twisted Nematic) method and VA (Vertical Alignment) method; IPS (In Plane Switching) method; and lateral electric field methods such as FFS (Fringe Field Switching) method. In a lateral electric field method in which electrodes are formed only on one side of a substrate and an electric field is applied in a direction parallel to the substrate, there is known a liquid crystal display element having a wider viewing angle characteristic and capable of performing high-quality display as compared with a conventional longitudinal electric field method in which a voltage is applied to electrodes formed on upper and lower substrates to drive liquid crystal.

[0003] The most industrially widespread liquid crystal alignment film is produced by performing a so-called rubbing treatment, which is a unidirectional rubbing of the surface of a film formed on an electrode substrate and formed of polyamic acid and / or polyimide obtained by imidizing the polyamic acid, using a cloth such as cotton, nylon, or polyester. The rubbing treatment is a simple and industrially useful method with excellent productivity. However, with the high performance, high definition, and large size of liquid crystal display elements, various problems such as damage to the surface of the alignment film, dust generation, mechanical force, influence caused by static electricity, and unevenness in the alignment treatment surface during the rubbing treatment have become apparent. As an alignment treatment method to replace the rubbing treatment, a photo-alignment method of imparting liquid crystal alignment ability by irradiating polarized radiation is known. Regarding the photo-alignment method, methods using a photo-isomerization reaction, a photo-crosslinking reaction, a photo-decomposition reaction, etc. have been proposed (for example, see Non-Patent Document 1, Patent Documents 1 and 2).

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Laid-Open No. 9-297313

[0007] Patent Document 2: Japanese Patent Laid-Open No. 2004-206091

[0008] Non-Patent Document

[0009] Non-Patent Document 1: "Functional Materials", November 1997 issue, Vol. 17, No. 11, pages 13 to 22 Summary of the Invention

[0010] Problems to be Solved by the Invention

[0011] In the liquid crystal alignment films used in the above-mentioned IPS driving method and FFS driving method liquid crystal display elements, a high alignment restraining force is required to suppress afterimages (hereinafter also referred to as AC afterimages) generated by long-term AC driving. In addition, in the case of performing alignment treatment by the photo-alignment method, the light irradiation amount is a factor that affects the energy cost and production speed. Therefore, it is more preferable to be able to perform alignment treatment with a small light irradiation amount.

[0012] However, the present inventors have studied and found that a liquid crystal alignment film capable of achieving liquid crystal alignment with a small light irradiation amount in the alignment treatment using the photo-alignment method has problems such as being prone to generating AC afterimages or unevenness (non-uniformity) of the twist angle of the liquid crystal in the plane of the liquid crystal alignment film. Therefore, it can be envisioned that the risk of generating AC afterimages due to liquid crystal driving is high, and it is difficult to obtain a liquid crystal display element with a high display quality level having excellent contrast. In addition, when aiming for a larger screen size of the liquid crystal display element, the liquid crystal alignment is incomplete in a part of the obtained liquid crystal alignment film, and it may be difficult to obtain a liquid crystal display element with a high display quality level having excellent contrast.

[0013] In view of the above, an object of the present invention is to provide a liquid crystal aligning agent, the following liquid crystal alignment film, and a liquid crystal display element using the following liquid crystal alignment film, wherein the liquid crystal aligning agent can obtain a liquid crystal alignment film that suppresses AC afterimages even when the light irradiation amount in the alignment treatment using the photo-alignment method is small. In addition, the present invention provides a liquid crystal display element using the liquid crystal aligning agent, the following liquid crystal alignment film, and the following liquid crystal alignment film, wherein the liquid crystal aligning agent can obtain a liquid crystal alignment film that can reduce the unevenness (non-uniformity) of the twist angle of the liquid crystal in the plane of the liquid crystal alignment film.

[0014] Means for Solving the Problems

[0015] The present inventors conducted in-depth research to achieve the above object, and as a result, found that by using a specific tetracarboxylic acid component and a specific diamine component, it is effective for achieving the above object. And it was found that a liquid crystal aligning agent based on the following constitution is optimal for achieving the above object, thus completing the present invention.

[0016] Thus, based on the above insights, the present invention has the following content.

[0017] A liquid crystal aligning agent containing at least one polymer (P) selected from the group consisting of a polyimide precursor obtained from a tetracarboxylic acid component and a diamine component and a polyimide which is an imidized product of the polyimide precursor, wherein the tetracarboxylic acid component contains at least one selected from the group consisting of tetracarboxylic dianhydrides represented by the following formula (1) and derivatives thereof, and the diamine component contains a diamine represented by the following formula (2).

[0018]

[0019] (R 1 ~R 4 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group, and at least one of R 1 ~R 4 represents a group other than a hydrogen atom in the above definition.

[0020] A2 represents an alkyl group having 1 to 3 carbon atoms.)

[0021] It should be noted that throughout this specification, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc., and * represents a bonding bond. Boc represents a tert-butoxycarbonyl group.

[0022] Advantages of the Invention

[0023] By using the liquid crystal aligning agent of the present invention, a liquid crystal alignment film that suppresses AC afterimages can be obtained even when the amount of light irradiation during the alignment treatment using the photo-alignment method is small. In addition, a liquid crystal alignment film capable of reducing the non-uniformity (inhomogeneity) of the twist angle of the liquid crystal in the plane of the liquid crystal alignment film can be obtained.

[0024] The mechanism by which the present invention achieves the above effects is not necessarily clear, but the following can be presumed as one of the reasons.

[0025] The liquid crystal aligning agent of the present invention does not locally undergo thermal cyclization, and the decrease in molecular weight after irradiation with polarized ultraviolet light is suppressed, thereby obtaining a liquid crystal alignment film that suppresses AC afterimages and can reduce the non-uniformity (inhomogeneity) of the twist angle of the liquid crystal in the plane of the liquid crystal alignment film. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic cross-sectional view showing an example of a liquid crystal display element of the in-plane switching mode of the present invention.

[0027] Figure 2This is a schematic cross-sectional view showing another example of the lateral electric field mode liquid crystal display element of the present invention. Detailed implementation mode

[0028] <Polymer (P)>

[0029] The liquid crystal aligning agent of the present invention contains at least one polymer (P) selected from the group consisting of a polyimide precursor obtained by using a tetracarboxylic acid component and a diamine component and a polyimide which is an imidized product of the polyimide precursor. The tetracarboxylic acid component contains at least one selected from the group consisting of the tetracarboxylic dianhydride represented by the above formula (1) and its derivatives (also referred to as a specific alicyclic tetracarboxylic acid component (p) in the present invention), and the diamine component contains the diamine represented by the above formula (2) (also referred to as a specific diamine (p) in the present invention). The polymer (P) can be one kind or two or more kinds.

[0030] Here, the polyimide precursor is a polymer such as polyamic acid or polyamic acid ester that can be imidized to obtain polyimide.

[0031] (Tetracarboxylic acid component)

[0032] The polyamic acid (P') which is a polyimide precursor of the polymer (P) can be obtained, for example, by a polymerization reaction of a diamine component containing the above specific diamine (p) and the tetracarboxylic dianhydride represented by the above formula (1).

[0033] When producing the polymer (P), the tetracarboxylic acid component reacting with the diamine component can use not only the tetracarboxylic dianhydride but also derivatives of tetracarboxylic acid such as tetracarboxylic acid, tetracarboxylic dihalide, tetraalkyl ester of tetracarboxylic acid or tetraalkyl ester dihalide of tetracarboxylic acid.

[0034] As the above R 1 ~R 4 Specific examples of the alkyl group having 1 to 6 carbon atoms include: methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, etc. As the above R 1 ~R 4 Specific examples of the alkenyl group having 2 to 6 carbon atoms include: vinyl, propenyl, butenyl, etc., and these groups can be linear or branched. As the above R 1 ~R 4 Specific examples of the alkynyl group having 2 to 6 carbon atoms include: ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, etc. As the above R 1 ~R 4The monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom may include: fluoromethyl, trifluoromethyl, pentafluoroethyl, pentafluoropropyl, trifluoromethoxy, 2,2,2-trifluoroethyl, 2,2,2-trifluoroethoxy, and the like.

[0035] From the viewpoint of high photoreactivity, more preferably, R 1 ~R 4 At least two of them represent groups other than a hydrogen atom in the above definition. In addition, from the viewpoint of high photoreactivity, more preferably, R 1 and R 4 represent groups other than a hydrogen atom, and R 2 and R 3 represent a hydrogen atom.

[0036] From the viewpoint of high photoreactivity, R 1 ~R 4 are each independently a hydrogen atom or a methyl group. More preferably, at least one of R 1 ~R 4 is a methyl group. Further preferably, at least two of R 1 ~R 4 are methyl groups. Most preferably, R 1 and R 4 are methyl groups, and R 2 and R 3 are hydrogen atoms.

[0037] The usage ratio of the above-mentioned specific alicyclic tetracarboxylic acid component (p) is more preferably 10 mol% or more, further preferably 20 mol% or more, and most preferably 50 mol% or more relative to 1 mol of all the tetracarboxylic acid components used in the polymer (P).

[0038] The tetracarboxylic acid component used for manufacturing the polymer (P) may include a tetracarboxylic acid component other than the above-mentioned specific alicyclic tetracarboxylic acid component (p) (hereinafter, also referred to as other tetracarboxylic acid components).

[0039] When, in addition to using the above-mentioned specific alicyclic tetracarboxylic acid component (p), other tetracarboxylic acid components are also used in combination, the content of the specific alicyclic tetracarboxylic acid component (p) is more preferably 95 mol% or less, further preferably 90 mol% or less relative to 1 mol of all the tetracarboxylic acid components used in the polymer (P).

[0040] In addition, the content of the other tetracarboxylic acid components is more preferably 5 mol% to 90 mol%, further preferably 10 to 80 mol%, and most preferably 10 to 50 mol% relative to 1 mol of all the tetracarboxylic acid components used in the polymer (P).

[0041] Examples of the other tetracarboxylic acid components include acyclic aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides other than the tetracarboxylic dianhydrides represented by the above formula (1), aromatic tetracarboxylic dianhydrides, or derivatives thereof.

[0042] Among them, the acyclic aliphatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. Among them, it is not necessary to be composed only of a chain hydrocarbon structure, and it may have an alicyclic structure or an aromatic ring structure in a part thereof.

[0043] The alicyclic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an alicyclic structure. Among them, none of these four carboxyl groups is bonded to an aromatic ring. In addition, it is not necessary to be composed only of an alicyclic structure, and it may have a chain hydrocarbon structure or an aromatic ring structure in a part thereof.

[0044] The aromatic tetracarboxylic dianhydride is not particularly limited as long as it is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an aromatic ring.

[0045] Regarding the above acyclic aliphatic or alicyclic tetracarboxylic dianhydrides or derivatives thereof, from the viewpoint of improving the liquid crystal alignment, a tetracarboxylic dianhydride or a derivative thereof having at least one partial structure selected from the group consisting of a cyclobutane ring structure, a cyclopentane ring structure, and a cyclohexane ring structure is preferably used. Regarding the above aromatic tetracarboxylic dianhydride or a derivative thereof, from the viewpoint of improving the liquid crystal alignment, a tetracarboxylic dianhydride or a derivative thereof having a benzene ring structure is preferably used.

[0046] Specific examples of the tetracarboxylic dianhydride or a derivative thereof that can be used as the other tetracarboxylic acid component include the following embodiments.

[0047] 1,2,3,4-butanetetracarboxylic dianhydride or (Q)2-A (where Q represents a monovalent succinic anhydride structure, A represents -CH2-, an alkylene group having 2 to 18 carbon atoms, or a divalent organic group in which a part of -CH2- in the alkylene group is substituted with at least any one of a phenylene group, -O-, -NR- (R represents a hydrogen atom or a methyl group), -C(=O)-NR- (R represents a hydrogen atom or a methyl group), -C(=O)-O-, and -O-C(=O)- (where -O- or -NR- do not bond adjacent to each other)) and other acyclic aliphatic tetracarboxylic dianhydrides; 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3',4,4'-dicyclohexyltetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 4-(2,5-dioxotetrahydrofuran-3-yl)tetralin-1,2-dicarboxylic anhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic dianhydride, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride and other alicyclic tetracarboxylic dianhydrides; pyromellitic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3',4,4'-diphenylethertetracarboxylic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)-2,2-diphenylpropane dianhydride, ethylene glycol bistrimellitic anhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 4,4'-carbonyldiphthalic anhydride, 4,4'-(1,4-phenylenedioxy)bis(phthalic anhydride) or 4,4'-(1,4-phenylenedimethylene)bis(phthalic anhydride) and other aromatic tetracarboxylic dianhydrides; in addition, tetracarboxylic dianhydrides described in Japanese Patent Application Laid-Open No. 2010-97188, etc.

[0048] (specific diamine (p))

[0049] The specific diamine (p) of the present invention is the diamine represented by the above formula (2). The above specific diamine (p) may be used alone or in combination of two or more.

[0050] The content of the specific diamine (p) is preferably 5 mol% or more, more preferably 10 mol% or more, relative to 1 mol of the diamine component used to produce the polymer (P).

[0051] A2 in the above formula (2) is an alkyl group having 1 to 3 carbon atoms. Specific examples include methyl, ethyl, n-propyl, or isopropyl. From the viewpoint of improving the liquid crystal alignment, A2 is more preferably methyl or ethyl.

[0052] More preferred specific examples of the diamine represented by the above formula (2) include diamines represented by any of the following formulas (d2-1) to (d2-3).

[0053]

[0054] The above diamine component used to produce the polymer (P) may contain a diamine other than the specific diamine (p) (hereinafter also referred to as other diamines). When using the above specific diamine (p) in combination with other diamines, the content of the specific diamine (p) relative to the diamine component is preferably 95 mol% or less, more preferably 90 mol% or less, relative to 1 mol of the diamine component used to produce the polymer (P).

[0055] Examples of other diamines are listed below, but are not limited to these diamines. The above other diamines may be used alone, or two or more may be used in combination, or three or more may be used in combination.

[0056] p-Phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, m-phenylenediamine, 2,4-dimethyl-m-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(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 4,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'-diaminobiphenyl, 2,3'-diaminobiphenyl and other diaminobiphenyl compounds; the diamine represented by the following formula (d AL ) (preferably represented by the following formula (d AL -1) to (d AL-11) diamine), 1,7-bis(4-aminophenoxy)heptane, 1,7-bis(3-aminophenoxy)heptane, 1,8-bis(4-aminophenoxy)octane, 1,8-bis(3-aminophenoxy)octane, 1,9-bis(4-aminophenoxy)nonane, 1,9-bis(3-aminophenoxy)nonane, 1,10-bis(4-aminophenoxy)decane, 1,10-bis(3-aminophenoxy)decane, 1,11-bis(4-aminophenoxy)undecane, 1,11-bis(3-aminophenoxy)undecane, 1,12-bis(4-aminophenoxy)dodecane, 1,12-bis(3-aminophenoxy)dodecane, 1,2-bis(6-amino-2-naphthyloxy)ethane, 1,2-bis(6-amino-2-naphthyl)ethane, or 6-[2-(4-aminophenoxy)ethoxy]-2-naphthylamine), 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)diphenyl ether, 1,4-bis[4-(4-aminophenoxy)phenoxy]benzene and other diamines having a diphenyl ether structure (hereinafter, they are also collectively referred to as the first diamine); N,N'-bis(4-aminophenyl)-cyclobutane-(1,2,3,4)-tetracarboxylic diimide, N,N'-bis(4-aminophenyl)-1,3-dimethylcyclobutane-(1,2,3,4)-tetracarboxylic diimide, N,N'-bis(2,2'-bis(trifluoromethyl)-4'-amino-1,1'-biphenyl-4-yl)-cyclobutane-(1,2,3,4)-tetracarboxylic diimide and other diamines having a tetracarboxylic diimide structure; 4,4'-diaminoazobenzene and other aromatic diamines having an azobenzene structure; 4,4'-diaminostilbene and other aromatic diamines having a stilbene structure; diaminodiphenylacetylene and other aromatic diamines having a diphenylacetylene structure, 4,4'-diaminochalcone and other aromatic diamines having a chalcone structure; 1,4-phenylenebis(4-aminobenzoate), 1,4-phenylenebis(3-aminobenzoate), 1,3-phenylenebis(4-aminobenzoate), 1,3-phenylenebis(3-aminobenzoate), bis(4-aminophenyl)terephthalate, bis(3-aminophenyl)terephthalate, bis(4-aminophenyl) isophthalate, bis(3-aminophenyl) isophthalate and other aromatic diamines having a phenyl benzoate structure;Or diamines having a photo-orienting group represented by an aromatic diamine having a cinnamate structure, such as (E)-4-aminophenyl 3-(4-aminophenyl)acrylate, (E)-4-amino-2-methylphenyl 3-(4-aminophenyl)acrylate, (E)-4-aminophenethyl 3-(4-aminophenyl)acrylate, (E,E)-bis-(4'-aminophenyl) 1,3-benzenediacrylate, (E,E)-bis-(4'-aminophenyl) 1,4-benzenediacrylate, or 4-aminophenyl (2E)-3-(4-aminophenyl)-2-methyl-2-propenoate; diamines having a photopolymerizable group at the terminal, such as 2-(2,4-diaminophenoxy)ethyl methacrylate or 2,4-diamino-N,N-diallylaniline; diamines having a function of a radical polymerization initiator, such as 1-(4-(2-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylpropanone or 2-(4-(2-hydroxy-2-methylpropanoyl)phenoxy)ethyl 3,5-diaminobenzoate; diamines having an amide bond, such as 4,4'-diaminobenzanilide; diamines having a urea bond, such as 1,3-bis(4-aminophenyl)urea, 1,3-bis(4-aminobenzyl)urea, or 1,3-bis(4-aminophenethyl)urea; 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(3-aminophenyl)hexafluoropropane, 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(3-amino-4-methylphenyl)propane, 4,4'-diaminobenzophenone, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene;2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis(4-aminophenyl)-piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, N-[3-(1H-imidazol-1-yl)propyl]-3,5-diaminobenzamide, 4-[4-[(4-aminophenoxy)methyl]-4,5-dihydro-4-methyl-2-oxazolyl]-aniline, or a heterocyclic diamine such as a diamine represented by the following formula (z-1) to formula (z-13), 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl-N-methylamine, a diamine represented by the following formula (z-14), N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine, or N,N'-bis(4-aminophenyl)-N,N'-dimethyl-1,4-benzenediamine, etc., which are represented by a diamine having a diphenylamine structure and having at least one nitrogen atom-containing structure selected from the group consisting of a nitrogen atom-containing heterocycle, a secondary amino group, and a tertiary amino group (hereinafter, also referred to as a specific nitrogen atom-containing structure. Among them, the specific nitrogen atom-containing structure is a functional group other than the two amino groups participating in the polycondensation reaction) (wherein, the molecule does not have an amino group bonded to a protecting group that detaches by heating and is replaced by a hydrogen atom); 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-bis(4-aminophenyl)ethane-3,3'-dicarboxylic acid, 4,4'-diaminodiphenyl ether-3,3'-dicarboxylic acid, etc., diamines having a carboxyl group; 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 1-(4-aminophenyl)-1,3,3-trimethyl-1H-indan-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine;Diamines having a group “—N(D)—” (where D represents a protecting group that detaches upon heating and is replaced by a hydrogen atom, preferably a carbamate-based protecting group, more preferably tert-butoxycarbonyl. Among them, the above-mentioned specific diamines are excluded), such as those represented by the following formulas (5-1) to (5-6); cholesteryloxy-3,5-diaminobenzene, cholestenyloxy-3,5-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholesteryl 3,5-diaminobenzoate, cholestenyl 3,5-diaminobenzoate, lanosterol 3,5-diaminobenzoate, and 3,6-bis(4-aminobenzoyloxy)cholestane and other diamines having a steroid skeleton; diamines represented by the following formulas (V-1) to (V-2); aromatic diamines represented by 2,7-diaminofluorene, 9,9-bis(4-aminophenyl)fluorene and other diamines having a fluorene skeleton; diamines having a siloxane bond such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane; acyclic aliphatic diamines represented by m-xylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, etc.; alicyclic diamines represented by 1,3-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), etc. In addition, diamines in which two amino groups are bonded to a group represented by any one of the formulas (Y-1) to (Y-167) described in WO2018 / 117239;

[0057]

[0058] (Ar1 and Ar1' each independently represent a benzene ring, a biphenyl structure, or a naphthalene ring, and one or more hydrogen atoms on the benzene ring, the biphenyl structure, or the naphthalene ring are optionally substituted by a monovalent group. L1 and L 1’ each independently represent a single bond, —O—, —C(═O)—, or —O—C(═O)—. A represents —CH2—, an alkylene group having 2 to 12 carbon atoms, or a divalent organic group in which at least any one of —O—, —C(═O)—O—, and —O—C(═O)— is inserted between the carbon-carbon bonds of the alkylene group. Among them, any hydrogen atom of A is optionally substituted by a halogen atom.)

[0059] One or more hydrogen atoms on the above-mentioned benzene ring, biphenyl structure, or naphthalene ring are optionally substituted by a monovalent group. Examples of the monovalent group include: a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, a fluoroalkenyl group having 2 to 3 carbon atoms, a fluoroalkoxy group having 1 to 3 carbon atoms, an alkoxycarbonyl group having 2 to 3 carbon atoms, a cyano group, a nitro group, etc.

[0060]

[0061] (In formula (dAL In (1-2), the sum of l, m, and n is from 1 to 12.

[0062] Formula (d AL -6), the sum of m1, m2, and n is from 1 to 12. In formula (d AL -8), the sum of m1, m2, and n is from 3 to 12.

[0063] Formula (d AL -11), the sum of l, m, and n is from 3 to 12.)

[0064]

[0065]

[0066] In the above formula (V-1), m and n are integers from 0 to 3, satisfying 1 ≤ m + n ≤ 4. j is an integer of 0 or 1. X 1 represents -(CH2) a -(where a is an integer from 1 to 15), -CONH-, -NHCO-, -CO-N(CH3)-, -NH-, -O-, -CH2O-, -CH2-OCO-, -COO-, or -OCO-. R 1 represents a fluorine atom, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and a alkoxyalkyl group having 2 to 10 carbon atoms and other monovalent groups. In the above formula (V-2), X 2 represents -O-, -CH2O-, -CH2-OCO-, -COO-, or -OCO-. When there are two m, n, X 1 , R 1 , they each independently have the above definitions.

[0067] As the heterocyclic ring containing a nitrogen atom optionally possessed by the diamine having the above specific nitrogen atom-containing structure, for example, pyrrole, imidazole, pyrazole, triazole, pyridine, pyrimidine, pyridazine, pyrazine, indole, benzimidazole, purine, quinoline, isoquinoline, naphthyridine, quinoxaline, phthalazine, triazine, carbazole, acridine, piperidine, piperazine, pyrrolidine, hexamethyleneimine can be cited. Among them, pyridine, pyrimidine, pyrazine, piperidine, piperazine, quinoline, carbazole, or acridine is preferred.

[0068] From the viewpoint of improving the liquid crystal alignment property, the above other diamine can be a diamine selected from the group consisting of the above first diamine, the diamine having a tetracarboxylic diimide structure, the diamine having an amide bond, the diamine having a urea bond, and the diamine having a group "-N(D)-".

[0069] The content of the above other diamine is more preferably 10 to 95 mol%, further preferably 10 to 90 mol%, still more preferably 20 to 90 mol% relative to 1 mol of the diamine component used to produce the polymer (P). In addition, when two or more other diamines are included, the content of each diamine constituting each other diamine can be 30 mol% or less.

[0070] (Liquid crystal aligning agent)

[0071] The liquid crystal aligning agent of the present invention is a liquid composition in which the polymer (P) and other components used as needed are preferably dispersed or dissolved in an appropriate solvent.

[0072] The liquid crystal aligning agent of the present invention may contain other polymers in addition to the polymer (P). Specific examples of other polymers include polymers selected from the group consisting of the following two types of polymers, polysiloxanes, polyesters, polyamides, polyureas, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene derivatives, poly(styrene - maleic anhydride) copolymers, poly(isobutene - maleic anhydride) copolymers, poly(vinyl ether - maleic anhydride) copolymers, poly(styrene - phenyl maleimide) derivatives, poly(meth)acrylates, etc., other than the polymer (P) described above. One of the two types of polymers is at least one selected from the group consisting of a polyimide precursor obtained by using a tetracarboxylic acid component that does not contain the above - specific alicyclic tetracarboxylic acid component (p) and a polyimide that is an imidized product of the polyimide precursor. The other of the two types of polymers is at least one selected from the group consisting of a polyimide precursor obtained by using a diamine component that does not contain the above - specific diamine (p) and a polyimide that is an imidized product of the polyimide precursor. (In the present invention, the above polymers are collectively referred to as polymer (B)).

[0073] Specific examples of the poly(styrene - maleic anhydride) copolymer include SMA1000, SMA2000, SMA3000 (manufactured by Cray Valley), GSM301 (manufactured by Gifu Shellac Manufacturing), etc. Specific examples of the poly(isobutene - maleic anhydride) copolymer include ISOBAM - 600 (manufactured by Kuraray). Specific examples of the poly(vinyl ether - maleic anhydride) copolymer include Gantrez AN - 139 (methyl vinyl ether maleic anhydride resin, manufactured by Ashland).

[0074] Among them, from the viewpoint of less afterimage derived from residual DC, polymer (B) is more preferred.

[0075] One of the above other polymers may be used alone, or two or more thereof may be used in combination. The content ratio of the other polymers is preferably 90 parts by mass or less, more preferably 10 to 90 parts by mass, and still more preferably 20 to 80 parts by mass, based on 100 parts by mass in total of the polymers contained in the liquid crystal aligning agent.

[0076] (Polymer (B))

[0077] Specific examples of the tetracarboxylic acid component used to produce the above polymer (B) include the same compounds as those exemplified for the compound in polymer (P), and may include: acyclic aliphatic tetracarboxylic dianhydride, alicyclic tetracarboxylic dianhydride, aromatic tetracarboxylic dianhydride or their derivatives. The tetracarboxylic acid component for producing polymer (B) more preferably contains a tetracarboxylic dianhydride or its derivative having at least one partial structure selected from the group consisting of a benzene ring, a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring (hereinafter, they will also be referred to as specific tetracarboxylic acid component (B)).

[0078] In addition, the content of the above specific tetracarboxylic acid component (B) is preferably 10 mol% or more, more preferably 20 mol% or more, and still more preferably 50 mol% or more, based on 1 mol of all the tetracarboxylic acid components used to produce polymer (B).

[0079] As the diamine component for obtaining polymer (B), for example, the diamines exemplified for the above polymer (P) can be mentioned. Among them, it preferably contains at least one diamine selected from the group consisting of the above first diamine, diamine having a urea bond, diamine having an amide bond, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(3-aminophenyl)hexafluoropropane, 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl)propane, 2,2-bis(3-amino-4-methylphenyl)propane, 4,4'-diaminobenzophenone, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene, the above diamine having a specific nitrogen atom-containing structure, the above diamine having a carboxyl group, 4-(2-(methylamino)ethyl)aniline, and 4-(2-aminoethyl)aniline (in the present invention, they will also be referred to as specific diamine (b)). The above diamine component may use one diamine alone, or two or more thereof may be used in combination.

[0080] When using the above-mentioned specific diamine (b), its content is preferably 10 mol% or more, more preferably 20 mol% or more, based on all the diamine components used for producing the polymer (B). When using a diamine other than the specific diamine (b), the content of the specific diamine (b) is preferably 90 mol% or less, more preferably 80 mol% or less, per 1 mol of all the diamine components used for producing the polymer (B).

[0081] (Production of polyamic acid)

[0082] The production of polyamic acid is carried out by reacting a diamine component with a tetracarboxylic acid component in an organic solvent. Regarding the usage ratio of the tetracarboxylic acid component to the diamine component for the production reaction of polyamic acid, the acid anhydride groups of the tetracarboxylic acid component preferably form a ratio of 0.5 to 2 equivalents, more preferably 0.8 to 1.2 equivalents, per 1 equivalent of the amino groups of the diamine component. Similar to a usual polycondensation reaction, the closer the equivalent of the acid anhydride groups of the tetracarboxylic acid component is to 1 equivalent, the larger the molecular weight of the resulting polyamic acid.

[0083] The reaction temperature during the production of polyamic acid is preferably -20 to 150 °C, more preferably 0 to 100 °C. In addition, the reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours. The production of polyamic acid can be carried out at any concentration, but the concentration of polyamic acid is preferably 1 to 50 mass%, more preferably 5 to 30 mass%. It is also possible to carry out the reaction at a high concentration in the initial stage and then add a solvent.

[0084] Specific examples of the above-mentioned organic solvents include: cyclohexanone, cyclopentanone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone. In addition, when the solubility of the polymer in the solvent is high, solvents such as 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.

[0085] (Production of polyamic acid ester)

[0086] Polyamic acid ester can be obtained, for example, by the following known methods:

[0087] [I] A method of reacting the polyamic acid obtained by the above method with an esterifying agent.

[0088] [II] A method of reacting a tetracarboxylic acid diester with a diamine.

[0089] [III] A method of reacting a tetracarboxylic acid diester dihalide with a diamine, etc.

[0090] (Manufacture of Polyimide)

[0091] In the case of polyimide, polyimide can be obtained by subjecting a polyimide precursor such as the above polyamic acid or polyamic acid ester to ring closure (imidization). It should be noted that the imidization rate referred to in this specification is the ratio of the imide group to the total amount of the imide group and carboxyl group (or their derivatives) derived from the tetracarboxylic dianhydride or its derivatives. The imidization rate does not necessarily have to be 100%, and can be arbitrarily adjusted according to the use and purpose.

[0092] As a method for imidizing the polyimide precursor, thermal imidization in which the solution of the polyimide precursor is heated while maintaining this state or catalytic imidization in which a catalyst is added to the solution of the polyimide precursor can be cited.

[0093] When thermally imidizing the polyimide precursor in solution, the temperature is preferably 100 to 400 °C, more preferably 120 to 250 °C, and it is preferably carried out while removing the water generated by the imidization reaction to the outside of the system.

[0094] Catalytic imidization of the polyimide precursor can be carried out by adding a basic catalyst and an acid anhydride to the solution of the polyimide precursor, and preferably stirring at -20 to 250 °C, more preferably at 0 to 180 °C. The amount of the basic catalyst is preferably 0.5 to 30 molar times, more preferably 2 to 20 molar times, the amount of the acid anhydride is preferably 1 to 50 molar times, more preferably 3 to 30 molar times, based on the amic acid group. As the basic catalyst, pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, etc. can be cited. Among them, pyridine has an appropriate basicity for the reaction to proceed, so it is preferred. As the acid anhydride, acetic anhydride, trimellitic anhydride, pyromellitic dianhydride, etc. can be cited. Among them, when acetic anhydride is used, purification after the reaction becomes easy, so it is preferred. The imidization rate based on catalytic imidization can be controlled by adjusting the amount of the catalyst, reaction temperature, and reaction time.

[0095] When recovering the produced polyimide precursor or polyimide from the reaction solution of the polyimide precursor or polyimide, it is only necessary to pour the reaction solution into a solvent to precipitate it. Examples of the solvent for precipitation include: methanol, ethanol, isopropanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, water, etc. The polymer precipitated by pouring into the solvent can be recovered by filtration and then dried at normal pressure or reduced pressure at room temperature or by heating. In addition, when the recovered polymer is repeatedly subjected to the operations of redissolving in an organic solvent and reprecipitating and recovering 2 to 10 times, the impurities in the polymer can be reduced. Examples of the solvent at this time include, for example: alcohols, ketones or hydrocarbons, etc. When using three or more solvents selected from these, the purification efficiency is further improved, so it is preferred.

[0096] When producing the polyimide precursor and polyimide in the present invention, an appropriate end-capping agent can also be used together with the tetracarboxylic acid component containing a tetracarboxylic dianhydride or its derivative and the diamine component containing a diamine to produce a capped polymer. The capped polymer has the effects of improving the film hardness of the liquid crystal alignment film obtained from the coating film and improving the adhesion characteristics between the sealant and the liquid crystal alignment film.

[0097] Examples of the ends of the polyimide precursor and polyimide in the present invention include: amino group, carboxyl group, acid anhydride group or a group derived from the end-capping agent described later. The amino group, carboxyl group, and acid anhydride group can be obtained by a usual condensation reaction or by end-capping using the following end-capping agent.

[0098] Examples of the end-capping agent include, for example: acid anhydrides such as acetic anhydride, maleic anhydride, nadic anhydride, phthalic anhydride, itaconic anhydride, 1,2-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-ethynylphthalic anhydride, etc.; dicarbonate diester compounds such as di-tert-butyl carbonate, diallyl carbonate, etc.; chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride, nicotinoyl chloride, etc.; 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, n-octylamine, etc.; isocyanates having an unsaturated bond such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate or 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, etc.

[0099] The use ratio of the end-capping agent is preferably set to 0.01 to 20 mol parts, more preferably 0.01 to 10 mol parts, relative to 100 mol parts of the total of the diamine components used.

[0100] The polystyrene-reduced weight-average molecular weight (Mw) of the polyimide precursor and the polyimide measured by gel permeation chromatography (GPC) is preferably from 1,000 to 500,000, more preferably from 2,000 to 300,000. In addition, the molecular weight distribution (Mw / Mn) represented by the ratio of Mw to the polystyrene-reduced number-average molecular weight (Mn) measured by GPC is preferably 15 or less, more preferably 10 or less. By being in this molecular weight range, good liquid crystal alignment properties of the liquid crystal display element can be ensured.

[0101] The organic solvent contained in the liquid crystal aligning agent of the present invention is not particularly limited as long as it can uniformly dissolve the polymer (P) and other polymers added as needed. Examples thereof include: N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyl lactamide, N,N-dimethylpropionamide, tetramethylurea, N,N-diethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, N-n-propyl-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-n-butyl-2-pyrrolidone, N-tert-butyl-2-pyrrolidone, N-n-pentyl-2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone (collectively referred to as good solvents), and the like. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, or γ-butyrolactone is preferred. The content of the good solvent is preferably 20 to 99% by mass, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass of the total solvent contained in the liquid crystal aligning agent.

[0102] In addition, the organic solvent contained in the liquid crystal aligning agent preferably uses a mixed solvent in which, in addition to the above solvents, a solvent (also called a poor solvent) that improves the coatability and the surface smoothness of the coating film when coating the liquid crystal aligning agent is used in combination. Specific examples of the poor solvent are described below, but are not limited thereto. The content of the poor solvent is preferably 1 to 80% by mass, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass of the total solvent contained in the liquid crystal aligning agent. The type and content of the poor solvent are appropriately selected according to the coating device, coating conditions, coating environment, etc. of the liquid crystal aligning agent.

[0103] Examples of the poor solvent include diisopropyl ether, diisobutyl ether, 2,6-dimethyl-4-heptanol, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-dibutoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol, 2-(2-butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, 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 diacetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, cyclohexyl acetate, 4-methyl-2-pentyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, 2,6-dimethyl-4-heptanone, etc.

[0104] Among them, 2,6-dimethyl-4-heptanol, 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 2,6-dimethyl-4-heptanone is preferred.

[0105] As a preferred combination of a good solvent and a poor solvent, examples include: N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone and propylene glycol diacetate; N,N-dimethyl lactamide and diisobutyl ketone; N-methyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate; N-methyl-2-pyrrolidone, ethyl 3-ethoxypropionate, and dipropylene glycol monomethyl ether; N-ethyl-2-pyrrolidone, ethyl 3-ethoxypropionate, and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, ethyl 3-ethoxypropionate, and diethylene glycol monopropyl ether; N-ethyl-2-pyrrolidone, ethyl 3-ethoxypropionate, and diethylene glycol monopropyl ether; N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether acetate; N-ethyl-2-pyrrolidone and dipropylene glycol dimethyl ether; N,N-dimethyl lactamide and ethylene glycol monobutyl ether; N,N-dimethyl lactamide and propylene glycol diacetate; N-ethyl-2-pyrrolidone and diethylene glycol diethyl ether; N-ethyl-2-pyrrolidone, diethylene glycol monoethyl ether, and butyl cellosolve acetate; N-methyl-2-pyrrolidone, diethylene glycol monomethyl ether, and butyl cellosolve acetate; N,N-dimethyl lactamide and diethylene glycol diethyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and diethylene glycol diethyl ether; N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone, and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and diisobutyl ketone; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and dipropylene glycol monomethyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and propylene glycol monobutyl ether; N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and propylene glycol diacetate; N-ethyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and dipropylene glycol dimethyl ether; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and diisobutyl ketone; γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and propylene glycol diacetate; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether, and diisobutyl ketone; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether, and diisopropyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether, and diisobutyl carbinol;N-methyl-2-pyrrolidone, γ-butyrolactone, and dipropylene glycol dimethyl ether; N-methyl-2-pyrrolidone, propylene glycol monobutyl ether, and dipropylene glycol dimethyl ether; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, and dipropylene glycol monomethyl ether; N-ethyl-2-pyrrolidone, diethylene glycol diethyl ether, and dipropylene glycol monomethyl ether; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, and propylene glycol diacetate; N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether, and diisobutyl ketone; N-ethyl-2-pyrrolidone, γ-butyrolactone, and diisobutyl ketone; N-ethyl-2-pyrrolidone, N,N-dimethyl lactamide, and diisobutyl ketone; N-methyl-2-pyrrolidone, ethylene glycol monobutyl ether, and ethylene glycol monobutyl ether acetate; γ-butyrolactone, ethylene glycol monobutyl ether acetate, and dipropylene glycol dimethyl ether; N-ethyl-2-pyrrolidone, ethylene glycol monobutyl ether acetate, and propylene glycol dimethyl ether; N-methyl-2-pyrrolidone, 4-methyl-2-pentyl acetate, and ethylene glycol monobutyl ether; N-ethyl-2-pyrrolidone, cyclohexyl acetate, and 4-hydroxy-4-methyl-2-pentanone; cyclohexanone and propylene glycol monomethyl ether; cyclopentanone and propylene glycol monomethyl ether; N-methyl-2-pyrrolidone, cyclohexanone, and propylene glycol monomethyl ether, etc.;

[0106] (Liquid crystal aligning agent)

[0107] The liquid crystal aligning agent of the present invention contains the above polymer (P), the above other polymers as required, and the above organic solvent.

[0108] The total content of the polymers contained in the liquid crystal aligning agent of the present invention can also be appropriately changed according to the setting of the thickness of the coating film to be formed. From the aspect of forming a uniform and defect-free coating film, it is preferably 1% by mass or more, and from the aspect of the storage stability of the solution, it is preferably 10% by mass or less. The particularly preferred total content of the polymers is 2 to 8% by mass.

[0109] The content of the polymer (P) used in the present invention is preferably 1 to 100% by mass, more preferably 10 to 100% by mass, and particularly preferably 20 to 100% by mass relative to the total of the polymers contained in the liquid crystal aligning agent.

[0110] In addition to containing the above-mentioned polymer (P), the above-mentioned other polymer, and the above-mentioned organic solvent, the liquid crystal aligning agent of the present invention may also contain components other than these (hereinafter, also referred to as additive components). Examples of the additive components include at least one crosslinking compound selected from the group consisting of a crosslinking compound having a substituent and a crosslinking compound having a polymerizable unsaturated group; a functional silane compound; a metal chelate compound; a curing accelerator; a surfactant; an antioxidant; a sensitizer; a preservative; a compound for adjusting the dielectric constant and resistance of the obtained liquid crystal alignment film; etc., wherein the substituent is selected from at least one of an epoxyethyl group, an oxetanyl group, a blocked isocyanate group, an oxazolinyl group, a cyclic carbonate group, a hydroxyalkyl group, and an alkoxy group.

[0111] As preferred specific examples of the above crosslinkable compounds, the following can be cited: 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, dibromoneopentyl glycol diglycidyl ether, 1,3,5,6 - tetraglycidyl - 2,4 - hexanediol, bisphenol A type epoxy resins such as EPIKOTE 828 (manufactured by MITSUBISHI CHEMICAL), bisphenol F type epoxy resins such as EPIKOTE 807 (manufactured by MITSUBISHI CHEMICAL), hydrogenated bisphenol A type epoxy resins such as YX - 8000 (manufactured by MITSUBISHI CHEMICAL), epoxy resins containing a biphenyl skeleton such as YX6954BH30 (manufactured by MITSUBISHI CHEMICAL), phenol novolak type epoxy resins such as EPPN - 201 (manufactured by Nippon Kayaku Co., Ltd.), (o -, m -, p -) cresol novolak type epoxy resins such as EOCN - 102S (manufactured by Nippon Kayaku Co., Ltd.), isocyanuric acid triglycidyl ester such as TEPIC (manufactured by Nissan Chemical Industries, Ltd.), alicyclic epoxy resins such as CELLOXIDE2021P (manufactured by Daicel Corporation), compounds containing a tertiary nitrogen atom represented by N, N, N’, N’ - tetraglycidyl - m - xylylenediamine, 1,3 - bis(N, N - diglycidylaminomethyl) cyclohexane or N, N, N’, N’ - tetraglycidyl - 4,4’ - diaminodiphenylmethane, compounds having two or more oxirane groups such as tetrakis(glycidyloxymethyl) methane; compounds having two or more oxetanyl groups described in paragraphs 0170 to 0175 of WO2011 / 132751; compounds having a blocked isocyanate group such as CORONATE AP stable M, CORONATE2503, 2515, 2507, 2513, 2555, MILLIONATE MS - 50 (all of the above, manufactured by TOSOH Corporation), TAKENATE B - 830, B - 815N, B - 820NSU, B - 842N, B - 846N, B - 870N, B - 874N, B - 882N (all of the above, manufactured by Mitsui Chemicals, Inc.); compounds having an oxazoline group such as 2,2’ - bis(2 - oxazoline), 2,2’ - bis(4 - methyl - 2 - oxazoline), 2,2’ - bis(5 - methyl - 2 - oxazoline), 1,2,4 - tris(2 - oxazolinyl) - benzene, and compounds such as EPOCROS (manufactured by Nippon Shokubai Co., Ltd.); compounds having a cyclic carbonate group described in paragraphs 0025 to 0030, 0032 of WO2011 / 155577;Compounds having hydroxyl groups and alkoxy groups, such as N,N,N',N'-tetrakis(2-hydroxyethyl)adipamide, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethoxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)-1,1,1,3,3,3-hexafluoropropane; compounds represented by glycerol mono(meth)acrylate, glycerol di(meth)acrylate (mixture of 1,2- and 1,3-types), glycerol tri(meth)acrylate, glycerol 1,3-diglycerolate di(meth)acrylate, pentaerythritol tri(meth)acrylate, diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, pentaethylene glycol mono(meth)acrylate, hexaethylene glycol mono(meth)acrylate.

[0112] The content of the crosslinkable compound is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, relative to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent.

[0113] As the compound for adjusting the dielectric constant and resistance, there can be mentioned monoamines having an aromatic heterocycle containing a nitrogen atom, such as 3-aminomethylpyridine. The content of the monoamine having an aromatic heterocycle containing a nitrogen atom is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, relative to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent.

[0114] As preferred specific examples of the above functional silane compounds, the following can be cited: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris[3-(trimethoxysilyl)propyl]isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, etc. The content of the functional silane compound is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, relative to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent.

[0115] The solid content concentration in the liquid crystal aligning agent (the proportion of the total mass of the components other than the solvent in the liquid crystal aligning agent in the total mass of the liquid crystal aligning agent) is appropriately selected in consideration of viscosity, volatility, etc., and is preferably 1 to 10% by mass.

[0116] The particularly preferred range of the solid content concentration varies depending on the method used when coating the liquid crystal aligning agent on the substrate. For example, in the case of using the spin coating method, the solid content concentration is particularly preferably 1.5 to 4.5% by mass. In the case of using the printing method, the solid content concentration is particularly preferably set to 3 to 9% by mass, thereby setting the solution viscosity to 12 to 50 mPa·s. In the case of using the inkjet method, the solid content concentration is particularly preferably set to 1 to 5% by mass, thereby setting the solution viscosity to 3 to 15 mPa·s. The temperature during the preparation of the liquid crystal aligning agent is preferably 10 to 50°C, more preferably 20 to 30°C.

[0117] (Liquid Crystal Alignment Film · Liquid Crystal Display Element)

[0118] By using the above liquid crystal aligning agent, a liquid crystal alignment film can be manufactured. The liquid crystal display element of the present invention includes the above liquid crystal alignment film. The operation mode of the liquid crystal display element of the present invention is not particularly limited. For example, it can be applied to various operation modes such as TN mode, STN (Super Twisted Nematic) mode, vertical alignment mode (including VA-MVA (Multi-domain Vertical Alignment) mode, VA-PVA (Patterned Vertical Alignment) mode, etc.), IPS mode, FFS mode, optically compensated bend mode (OCB mode), etc. The liquid crystal alignment film of the present invention is a liquid crystal alignment film suitable for liquid crystal display elements in horizontal alignment modes such as IPS mode or FFS mode.

[0119] The liquid crystal display element of the present invention can be manufactured, for example, by a method including the following steps (1) to (3), a method including steps (1) to (4), a method including steps (1) to (3), (3b), and (4), a method including steps (1) to (3), (3a), (3b), and (4), a method including steps (1) to (2) and (4), a method including steps (1) to (3), (4), and (5), or a method including steps (1) to (3), (4), and (6).

[0120] <Step (1): Step of coating the liquid crystal aligning agent on at least one of the first substrate and the second substrate>

[0121] Step (1) is a step of coating the liquid crystal aligning agent of the present invention on a substrate. Specific examples of Step (1) are described below.

[0122] For example, by an appropriate coating method such as a roll coater method, a spin coating method, a printing method, an inkjet method, etc., the liquid crystal aligning agent of the present invention is coated on one surface of a substrate provided with a patterned transparent conductive film. Here, as the substrate, as long as it has high transparency, there is no particular limitation, and plastic substrates such as acrylic substrates and polycarbonate substrates can also be used together with glass substrates and silicon nitride substrates. In addition, in a reflective liquid crystal display element, if it is only a single substrate, an opaque object such as a silicon wafer can also be used, and in this case, an electrode can also be made of a light-reflecting material such as aluminum. Moreover, in the case of manufacturing a liquid crystal display element in IPS mode or FFS mode, a substrate provided with an electrode composed of a transparent conductive film or a metal film patterned in a comb shape and a counter substrate without an electrode are used. The transparent conductive film can be, for example, indium tin oxide (ITO), indium zinc oxide (IZO), or a mixture thereof, and is formed by a known method.

[0123] As a method of coating a liquid crystal aligning agent on a substrate to form a film, the following methods can be cited: screen printing, offset printing, flexographic printing, inkjet method, spray method, etc. Among them, the coating and film-forming method using the inkjet method can be preferably used.

[0124] <Step (2): Step of baking the coated liquid crystal aligning agent>

[0125] Step (2) is a step of baking the liquid crystal aligning agent coated on the substrate to form a film. Specific examples of Step (2) are described below.

[0126] After coating the liquid crystal aligning agent on the substrate in Step (1), a heating unit such as a hot plate, a hot air circulation oven, or an IR (infrared) type oven can be used to evaporate the solvent, or thermal imidization of polyamic acid or polyamic acid ester can be performed. The drying and baking steps after coating the liquid crystal aligning agent of the present invention can be selected at any temperature and time, and can also be performed multiple times. As the temperature for reducing the solvent of the liquid crystal aligning agent, for example, it can be performed at 40 to 180°C. From the viewpoint of shortening the process, it can be performed at 40 to 150°C. As the baking time, there is no particular limitation, and 1 to 10 minutes or 1 to 5 minutes can be cited. In the case of performing thermal imidization of polyamic acid or polyamic acid ester, after the above steps, for example, a baking step can be added at a temperature range of 150 to 300°C or 150 to 250°C. As the baking time, there is no particular limitation, and a baking time of 5 to 40 minutes or 5 to 30 minutes can be cited.

[0127] If the film thickness of the baked film-like material is too thin, the reliability of the liquid crystal display element may sometimes decrease, so it is preferably 5 to 300 nm, more preferably 10 to 200 nm.

[0128] <Step (3): Step of performing an alignment treatment on the film obtained in Step (2)>

[0129] Step (3) is a step of performing an alignment treatment on the film obtained in Step (2) as appropriate. That is, in a liquid crystal display element with a horizontal alignment method such as the IPS method or the FFS method, an alignment energy imparting treatment can be performed on the coated film. On the other hand, in a vertically aligned liquid crystal display element such as the VA method or the PSA method, the formed coated film can be used as it is as a liquid crystal alignment film, or an alignment energy imparting treatment can be performed on the coated film. As a method for aligning the liquid crystal alignment film, a rubbing treatment method and a photoalignment treatment method can be cited, and the photoalignment treatment method is more preferably used.

[0130] As a photoalignment treatment method, the following methods can be cited: irradiating the surface of the above film-like material with radiation (more preferably polarized radiation) to impart liquid crystal alignment (also referred to as liquid crystal alignment energy).

[0131] As the radiation, ultraviolet rays or visible light having a wavelength of 100 to 800 nm can be used. Among them, ultraviolet rays having a wavelength of 100 to 400 nm are preferred, and ultraviolet rays having a wavelength of 200 to 400 nm are more preferred.

[0132] As the above-mentioned rubbing treatment method, for example, there can be mentioned a treatment in which a roller wound with a cloth made of fibers such as nylon, rayon, and cotton rubs the coating film in a certain direction.

[0133] In the above-mentioned photo-alignment treatment method, when the radiation is polarized, it can be linearly polarized or partially polarized. In addition, when the radiation used is linearly polarized or partially polarized, the irradiation can be performed from a direction perpendicular to the substrate surface, from an inclined direction, or a combination thereof. When irradiating non-polarized radiation, the irradiation direction is preferably set to an inclined direction.

[0134] The irradiation amount of the above-mentioned radiation is more preferably 1 to 10,000 mJ / cm 2 , further preferably 100 to 1,000 mJ / cm 2 , most preferably 100 to 500 mJ / cm 2 .

[0135] In addition, when irradiating radiation in the above-mentioned photo-alignment treatment method, in order to improve the liquid crystal alignment property, for example, the substrate having the film-like substance can be irradiated while being heated at 50 to 250 °C. The liquid crystal alignment film thus produced can make the liquid crystal molecules stably align in a certain direction.

[0136] The liquid crystal alignment film obtained by the above method can be further subjected to a step of contact treatment using a solvent (hereinafter, also referred to as step (3a)).

[0137] As the solvent for contact treatment in the above-mentioned step (3a), as long as it is a solvent that dissolves the decomposition products generated from the film-like substance by irradiation with radiation, there is no particular limitation. As specific examples, there can be mentioned: water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propyl acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate, etc. Among them, from the viewpoints of versatility and solvent safety, water, 2-propanol, 1-methoxy-2-propanol, or ethyl lactate is preferred. More preferably, water, 1-methoxy-2-propanol, or ethyl lactate. The solvent can be one kind or a combination of two or more kinds.

[0138] The liquid crystal alignment film for the liquid crystal display element of the present invention can also be produced by performing the following treatment of step (3b) after the above step (3). Step (3b) can be performed not only on the film that has been subjected to the alignment treatment in step (3), but also on the treated film that has been subjected to the treatment of the above step (3a).

[0139] <Step (3b): Step of performing heat treatment>

[0140] The radiation-irradiated coating film described above can also be subjected to heat treatment. The temperature of the heat treatment is preferably 50 to 300 °C, more preferably 120 to 250 °C. As the time of the heat treatment, it is preferably set to 1 to 30 minutes respectively.

[0141] <Step (4): Step of producing a liquid crystal cell by disposing a liquid crystal layer between a first substrate and a second substrate in a manner adjacent to the film after the alignment treatment>

[0142] Step (4) is a step of producing a liquid crystal cell by disposing a liquid crystal layer between a first substrate and a second substrate in a manner adjacent to the film after the alignment treatment. It should be noted that hereinafter, the case where liquid crystal alignment films are respectively formed on the first substrate and the second substrate will be exemplified. Specifically, the following two methods can be cited.

[0143] Regarding the first method, first, two substrates are disposed opposite to each other with a gap (cell gap) therebetween in a manner where their respective liquid crystal alignment films face each other. Then, the peripheral portions of the two substrates are bonded using a sealant, and a liquid crystal composition is injected into the cell gap defined by the substrate surfaces and the sealant. After contacting the film surface, the injection hole is sealed.

[0144] In addition, the second method is a method called the ODF (One Drop Fill) method. For example, a UV-curable resin composition (hereinafter, also referred to as a sealant) is coated on a specified portion of one of the two substrates on which the liquid crystal alignment film is formed, and the liquid crystal composition is further dropped at several specified locations on the liquid crystal alignment film surface. Then, the other substrate is bonded in a manner where the liquid crystal alignment films face each other, and the liquid crystal composition is spread over the entire surface of the substrate and brought into contact with the film surface. Then, ultraviolet light is irradiated onto the entire surface of the substrate to cure the sealant. In any case of using either method, it is ideal to further heat to the temperature at which the liquid crystal composition used becomes an isotropic phase and then slowly cool to room temperature, thereby removing the flow alignment during liquid crystal filling.

[0145] It should be noted that in the case where the coating film has been subjected to rubbing treatment, the two substrates are disposed opposite to each other in a manner where the rubbing directions of the respective coating films form a specified angle with each other, for example, an orthogonal or antiparallel angle.

[0146] As the sealant, for example, an epoxy resin containing a curing agent and alumina balls as spacers can be used.

[0147] The above liquid crystal composition is not particularly limited and is a composition containing at least one liquid crystal compound (liquid crystal molecule). Various liquid crystal compositions with positive or negative dielectric anisotropy can be used. It should be noted that hereinafter, a liquid crystal composition with positive dielectric anisotropy will also be referred to as a positive-type liquid crystal, and a liquid crystal composition with negative dielectric anisotropy will also be referred to as a negative-type liquid crystal.

[0148] The above liquid crystal composition may contain a liquid crystal compound having a fluorine atom, a hydroxyl group, an amino group, a fluorine atom-containing group (e.g., trifluoromethyl), a cyano group, an alkyl group, an alkoxy group, an alkenyl group, an isothiocyanate group, a heterocycle, a cycloalkane, a cycloalkene, a steroid skeleton, a benzene ring, or a naphthalene ring, or may also contain a compound having two or more rigid sites (mesogenic skeletons) exhibiting liquid crystallinity in the molecule (e.g., a bis-mesogenic compound in which two rigid biphenyl structures or terphenyl structures are linked by an alkylene group).

[0149] The liquid crystal composition can be a nematic liquid crystal composition, a smectic liquid crystal composition, or a cholesteric liquid crystal composition.

[0150] In addition, from the viewpoint of improving liquid crystal alignment, the above liquid crystal composition may further contain additives. Such additives include: photopolymerizable monomers such as compounds having a polymerizable group; optically active compounds (e.g., S-811 manufactured by Merck & Co., Inc.); antioxidants; ultraviolet absorbers; pigments; defoamers; polymerization initiators; or polymerization inhibitors, etc.

[0151] Examples of positive-type liquid crystals include ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, or MLC-7081 manufactured by Merck & Co., Inc.

[0152] Examples of negative-type liquid crystals include MLC-6608, MLC-6609, MLC-6610, or MLC-7026-100 manufactured by Merck & Co., Inc.

[0153] In addition, examples of liquid crystals containing a compound having a polymerizable group include MLC-3023 manufactured by Merck & Co., Inc.

[0154] The liquid crystal aligning agent of the present invention is also preferably used for a liquid crystal display element (a liquid crystal display element of the PSA method) manufactured through the following steps and having a liquid crystal layer between a pair of substrates each having an electrode: a liquid crystal composition containing a polymerizable compound polymerized by at least one of active energy rays and heat is disposed between the pair of substrates, a voltage is applied between the electrodes, and the polymerizable compound is polymerized by at least one of irradiation with active energy rays and heating (hereinafter, this step will also be referred to as step (5)).

[0155] In addition, the liquid crystal aligning agent of the present invention is also preferably used for a liquid crystal display element (a liquid crystal display element of the SC-PVA method) manufactured through the following steps and having a liquid crystal layer between a pair of substrates each having an electrode: a liquid crystal alignment film containing a polymerizable group polymerized by at least one of active energy rays and heat is disposed between the pair of substrates, and a voltage is applied between the electrodes (hereinafter, this step will also be referred to as step (6)).

[0156] And a liquid crystal display element can be obtained by attaching a polarizing plate to the outer surface of the liquid crystal cell as needed. Examples of the polarizing plate attached to the outer surface of the liquid crystal cell include a polarizing plate formed by sandwiching a polarizing film called an "H film" with a cellulose acetate protective film; or a polarizing plate constituted by the H film itself, which is formed by stretching and orienting polyvinyl alcohol and absorbing iodine.

[0157] An IPS substrate, which is a comb-tooth electrode substrate used in the IPS mode, has: a substrate; a plurality of linear electrodes formed on the substrate and arranged in a comb-tooth shape; and a liquid crystal alignment film formed on the substrate so as to cover the linear electrodes.

[0158] It should be noted that an FFS substrate, which is a comb-tooth electrode substrate used in the FFS mode, has: a substrate; a surface electrode formed on the substrate; an insulating film formed on the surface electrode; a plurality of linear electrodes formed on the insulating film and arranged in a comb-tooth shape; and a liquid crystal alignment film formed on the insulating film so as to cover the linear electrodes.

[0159] Figure 1 is a schematic cross-sectional view showing an example of a liquid crystal display element of the in-plane switching mode of the present invention and is an example of a liquid crystal display element of the IPS mode.

[0160] In Figure 1In the in-plane switching (IPS) mode liquid crystal display device 1 shown as an example, a liquid crystal 3 is sandwiched between a comb-shaped electrode substrate 2 having a liquid crystal alignment film 2c and a counter substrate 4 having a liquid crystal alignment film 4a. The comb-shaped electrode substrate 2 includes: a base material 2a; a plurality of linear electrodes 2b formed on the base material 2a and arranged in a comb shape; and a liquid crystal alignment film 2c formed on the base material 2a so as to cover the linear electrodes 2b. The counter substrate 4 includes: a base material 4b; and a liquid crystal alignment film 4a formed on the base material 4b. The liquid crystal alignment film 2c is, for example, the liquid crystal alignment film of the present invention. Similarly, the liquid crystal alignment film 4a is also the liquid crystal alignment film of the present invention.

[0161] In this in-plane switching (IPS) mode liquid crystal display device 1, when a voltage is applied to the linear electrodes 2b, an electric field is generated between the linear electrodes 2b as shown by the electric field lines L.

[0162] Figure 2 FIG. [FIG. number not provided in the original] is a schematic cross-sectional view showing another example of the in-plane switching (IPS) mode liquid crystal display device of the present invention, which is an example of a fringe field switching (FFS) mode liquid crystal display device.

[0163] In Figure 2 In the in-plane switching (IPS) mode liquid crystal display device 1 shown as an example, a liquid crystal 3 is sandwiched between a comb-shaped electrode substrate 2 having a liquid crystal alignment film 2h and a counter substrate 4 having a liquid crystal alignment film 4a. The comb-shaped electrode substrate 2 includes: a base material 2d; a planar electrode 2e formed on the base material 2d; an insulating film 2f formed on the planar electrode 2e; a plurality of linear electrodes 2g formed on the insulating film 2f and arranged in a comb shape; and a liquid crystal alignment film 2h formed on the insulating film 2f so as to cover the linear electrodes 2g. The counter substrate 4 includes: a base material 4b; and a liquid crystal alignment film 4a formed on the base material 4b. The liquid crystal alignment film 2h is, for example, the liquid crystal alignment film of the present invention. Similarly, the liquid crystal alignment film 4a is also the liquid crystal alignment film of the present invention.

[0164] In this in-plane switching (IPS) mode liquid crystal display device 1, when a voltage is applied to the planar electrode 2e and the linear electrodes 2g, an electric field is generated between the planar electrode 2e and the linear electrodes 2g as shown by the electric field lines L.

[0165] In addition to the liquid crystal alignment film for the above-mentioned uses, the liquid crystal alignment film of the present invention can also be applied to various uses, for example, it can be used as a liquid crystal alignment film for a retardation film; a liquid crystal alignment film for a scanning antenna or a liquid crystal array antenna; or a liquid crystal alignment film for a transmissive scattering type liquid crystal dimming element. Furthermore, it can also be used for uses other than the liquid crystal alignment film, for example, it can be used as a protective film (e.g., a protective film for a color filter), a spacer film, an interlayer insulating film, an antireflection film, a wiring coating film, an antistatic film, a motor insulating film (a gate insulating film for a flexible display).

[0166] The liquid crystal display element of the present invention can be effectively applied to various devices, for example, it can be used in various display devices such as clocks, portable game consoles, word processors, notebook computers, car navigation systems, camcorders, PDAs (Personal Digital Assistants), digital cameras, mobile phones, smartphones, various monitors, liquid crystal TVs, and information displays.

[0167] [Examples]

[0168] Hereinafter, examples are given to explain the present invention in more detail, but the present invention is not limited to these examples. The abbreviations of the compounds used and the measurement methods of various physical properties are as follows.

[0169] (Organic solvent)

[0170] NMP: N-methyl-2-pyrrolidone.

[0171] BCS: ethylene glycol monobutyl ether.

[0172] (Tetracarboxylic dianhydride)

[0173] CA-1: A compound represented by the following formula (CA-1).

[0174]

[0175] (Diamine)

[0176] DA-1 to DA-5: Compounds represented by the following formulas (DA-1) to (DA-5), respectively.

[0177]

[0178] <Measurement of viscosity>

[0179] Using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.), with a sample volume of 1.1 mL, using a conical rotor TE-1 (1°34’, R24), the measurement was carried out at a temperature of 25°C.

[0180] [Synthesis of polymer]

[0181] <Synthesis Example 1>

[0182] In a 50 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, DA-1 (0.449 g, 3.68 mmol), DA-2 (0.397 g, 3.67 mmol), DA-3 (1.80 g, 7.35 mmol), DA-4 (1.57 g, 4.90 mmol), DA-5 (1.95 g, 4.90 mmol) and NMP (70.9 g) were added, and while introducing nitrogen, the mixture was stirred at room temperature until dissolved. Then, CA-1 (5.30 g, 23.6 mmol) and NMP (13.2 g) were added, and the mixture was stirred at 40 °C for 20 hours to obtain a solution of polyamic acid (PAA-1) with a solid component concentration of 12% by mass (viscosity: 574 mPa·s).

[0183] <Synthesis Example 2>

[0184] In a 50 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, DA-2 (0.540 g, 4.99 mmol), DA-3 (1.83 g, 7.49 mmol), DA-4 (2.40 g, 7.49 mmol), DA-5 (1.99 g, 4.99 mmol) and NMP (68.4 g) were added, and while introducing nitrogen, the mixture was stirred at room temperature until dissolved. Then, CA-1 (5.31 g, 23.7 mmol) and NMP (20.1 g) were added, and the mixture was stirred at 40 °C for 20 hours to obtain a solution of polyamic acid (PAA-R1) with a solid component concentration of 12% by mass (viscosity: 402 mPa·s).

[0185] <Synthesis Example 3>

[0186] In a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, DA-2 (0.973 g, 9.00 mmol), DA-3 (2.20 g, 9.01 mmol), DA-4 (1.92 g, 5.99 mmol), DA-5 (2.39 g, 6.00 mmol) and NMP (86.0 g) were added, and while introducing nitrogen, the mixture was stirred at room temperature until dissolved. Then, CA-1 (6.42 g, 28.6 mmol) and NMP (15.0 g) were added, and the mixture was stirred at 40 °C for 20 hours to obtain a solution of polyamic acid (PAA-R2) with a solid component concentration of 12% by mass (viscosity: 382 mPa·s).

[0187] The specifications of the polyamic acids obtained in the above synthesis examples are shown in Table 1. In Table 1, the values in parentheses for the tetracarboxylic acid component and the diamine component represent the contents (mole parts) of each tetracarboxylic acid component and each diamine component relative to 100 mole parts of the total amount of the diamine components used in each polymerization step.

[0188] [Table 1]

[0189]

[0190] [Preparation of Liquid Crystal Alignment Agent]

[0191] <Example 1>

[0192] Using the solution of polyamic acid (PAA-1) obtained in Synthesis Example 1, it was diluted with NMP and BCS and stirred at room temperature for 2 hours, whereby a liquid crystal alignment agent (AL-1) with a mass ratio of polymer solid content to each solvent (polymer solid content∶NMP∶BCS) of 4.5∶75.5∶20 was obtained.

[0193] <Comparative Examples 1-2>

[0194] The polyamic acid used was replaced from (PAA-1) with (PAA-R1) to (PAA-R2), and the rest was carried out in the same manner as in Example 1, whereby liquid crystal alignment agents (AL-R1) to (AL-R2) were obtained.

[0195] The specifications of the liquid crystal alignment agents obtained in the above Examples and Comparative Examples are shown in Table 2.

[0196] [Table 2]

[0197]

[0198] In the liquid crystal alignment agents (AL-1), (AL-R1), and (AL-R2) obtained as described above, no abnormalities such as turbidity and precipitation were found, and they were confirmed to be uniform solutions. The liquid crystal alignment properties of the obtained liquid crystal alignment agents were evaluated.

[0199] [Fabrication of FFS-Driven Liquid Crystal Cell]

[0200] A liquid crystal cell having the structure of an FFS-mode liquid crystal display element was fabricated.

[0201] First, prepare a substrate with electrodes. The substrate used is a rectangular glass substrate with dimensions of 30 mm × 50 mm and a thickness of 0.7 mm. On the substrate, as the first layer, an ITO electrode with a pattern covering the entire surface, which constitutes a common electrode, is formed. On the common electrode of the first layer, as the second layer, a SiN (silicon nitride) film formed by CVD (chemical vapor deposition) method is formed. The film thickness of the SiN film in the second layer is 300 nm, which is the film thickness that functions as an interlayer insulating film. On the SiN film in the second layer, as the third layer, comb-shaped pixel electrodes formed by patterning an ITO film are arranged to form two pixels, namely the first pixel and the second pixel. The size of each pixel is 10 mm in length and 5 mm in width. This substrate with electrodes has a structure in which the common electrode in the first layer and the pixel electrodes in the third layer are insulated by the SiN film in the second layer.

[0202] The pixel electrodes in the third layer have a comb shape in which electrode lines with a width of 3 μm and bent at an inner angle of 160° within the central part are arranged in parallel at intervals of 6 μm. One pixel is formed by a plurality of electrode lines and has a first region and a second region with a line connecting the bent parts as the boundary.

[0203] Next, the liquid crystal aligning agent obtained above is filtered through a filter with a pore size of 1.0 μm and then coated on the above-mentioned substrate with electrodes (hereinafter referred to as the electrode substrate) and a glass substrate (hereinafter referred to as the counter substrate) having columnar spacers with a height of 4 μm and an ITO film formed on the back surface by spin coating. After drying on a hot plate at 80 °C for 1 minute, firing is performed in an infrared (IR) type oven at 230 °C for 30 minutes to form a coating film with a film thickness of 100 nm. On the surface of this coating film, with 200 mJ / cm 2The substrate with a liquid crystal alignment film was obtained by irradiating polarized ultraviolet light with an exposure amount through a 254 nm band-pass filter and a polarizer, and then baking it in an infrared (IR) oven at 230 °C for 30 minutes to perform an alignment treatment. It should be noted that the alignment treatment of the liquid crystal alignment film formed on the electrode substrate was performed in such a way that the direction bisecting the inner angle of the pixel bending portion was orthogonal to the liquid crystal alignment direction. When manufacturing the liquid crystal cell, the alignment treatment of the alignment film formed on the counter substrate was performed in such a way that the liquid crystal alignment direction on the electrode substrate was consistent with the liquid crystal alignment direction on the counter substrate. The above two substrates were used as a set, and a sealant (XN-1500T manufactured by Mitsui Chemicals, Inc.) was printed on the substrates using a dispenser, and the other substrate was bonded with the liquid crystal alignment film alignment directions facing each other at 0°. Then, the bonded substrates were pressed, and heated in a hot air circulation oven at 150 °C for 60 minutes to cure the sealant, thus producing an empty cell. A positive liquid crystal MLC-3019 (manufactured by Merck) was injected into the empty cell by a vacuum injection method, and the injection port was sealed, thereby obtaining a FFS-driven liquid crystal cell. Then, the obtained liquid crystal cell was heated at 120 °C for 1 hour, left overnight at 23 °C, and then used for evaluation.

[0204] [Evaluation of Liquid Crystal Alignment Stability]

[0205] This evaluation evaluates the afterimage (also called AC afterimage) caused by the degradation of the alignment performance of the liquid crystal alignment film during long-term AC driving.

[0206] For the FFS-driven liquid crystal cell manufactured above, under a high-brightness backlight with a surface temperature of 50 °C (light source: LED, brightness: 25000 cd / m 2) Above, an AC voltage of ±8V is applied at a frequency of 30Hz for 168 hours. Then, the pixel electrode and the common electrode of the liquid crystal cell are short-circuited and left at room temperature (23°C) for one day. Regarding the liquid crystal cell that has undergone the above treatment, the deviation between the liquid crystal alignment directions of the first region and the second region of the pixel in the state without voltage application is calculated in terms of angle. Specifically, the liquid crystal cell is placed between two polarizing plates arranged with their polarization axes orthogonal, the backlight is lit, and the configuration angle of the liquid crystal cell is adjusted to minimize the transmitted light intensity of the first region of the first pixel. Then, the rotation angle required to minimize the transmitted light intensity of the second region of the first pixel is calculated as the angle Δ. The second pixel is also compared between the first region and the second region in the same way, and the same angle Δ is calculated. And the average value of the angle Δ of the first pixel and the second pixel is calculated as the rotation angle Δ of the liquid crystal cell. It can be said that the smaller the value of this rotation angle Δ, the better the stability of the liquid crystal alignment. As an evaluation criterion, the case where the value of the rotation angle Δ of the liquid crystal cell obtained above is 0.05° or less is set as "good", and the case where the value of the rotation angle Δ of the liquid crystal cell obtained above is greater than 0.05° is set as "bad". The results are shown in Table 3.

[0207] [Evaluation of in-plane uniformity of contrast ratio]

[0208] The evaluation of the unevenness of the twist angle of the liquid crystal cell was performed using AxoStep manufactured by AXOMETRICS. The liquid crystal cell fabricated above was set on the measurement stage, and in the state without voltage application, the distribution of circular retardance in the pixel plane was measured, and 3σ, which is three times the standard deviation σ, was calculated. It can be said that the smaller the value of this 3σ, the better the in-plane uniformity. As an evaluation criterion, the case where the above 3σ value is 1.00 or less is set as "good", and the case where the above 3σ value is greater than 1.00 is set as "bad". The results are shown in Table 3.

[0209] [Table 3]

[0210]

[0211] Explanation of reference numerals:

[0212] 1: Transverse electric field type liquid crystal display element; 2: Comb electrode substrate; 2a: Substrate; 2b: Linear electrode; 2c: Liquid crystal alignment film; 2d: Substrate; 2e: Surface electrode; 2f: Insulating film; 2g: Linear electrode; 2h: Liquid crystal alignment film; 3: Liquid crystal; 4: Opposite substrate; 4a: Liquid crystal alignment film; 4b: Substrate; L: Power line.

[0213] It should be noted that the entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2022-197518 filed on December 9, 2022 are hereby incorporated by reference as the disclosure of the specification of the present invention.

Claims

1. A liquid crystal aligning agent, wherein, the liquid crystal aligning agent contains at least one polymer P selected from the group consisting of a polyimide precursor obtained by using a tetracarboxylic acid component and a diamine component and a polyimide which is an imidized product of the polyimide precursor, the tetracarboxylic acid component contains at least one selected from the group consisting of tetracarboxylic dianhydrides represented by the following formula (1) and derivatives thereof, and the diamine component contains a diamine represented by the following formula (2), R 1 ~R 4 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group, R 1 ~R 4 at least one of which represents a group other than a hydrogen atom in the above definition, A2 represents an alkyl group having 1 to 3 carbon atoms.

2. The liquid crystal aligning agent according to claim 1, wherein, the content of the diamine represented by the formula (2) is 5 mol% or more per 1 mol of the diamine component used for manufacturing the polymer P.

3. The liquid crystal aligning agent according to claim 1, wherein, the diamine represented by the formula (2) is a diamine represented by any one of the following formulas (d2-1) to (d2-3), 4. The liquid crystal aligning agent according to claim 1, wherein, R in the formula (1) 1 ~R 4 At least two of them represent a group other than a hydrogen atom in the said definition.

5. The liquid crystal aligning agent according to claim 1, wherein, the content of the tetracarboxylic dianhydride represented by the formula (1) and its derivatives is 10 mol% or more per 1 mol of the tetracarboxylic acid component used for manufacturing the polymer P.

6. The liquid crystal aligning agent according to claim 1, wherein, The diamine component further contains other diamines selected from the group consisting of phenylenediamine, diaminobiphenyl compounds, diamines represented by the following formula (d AL ), diamines having a diphenyl ether structure, diamines having a tetracarboxylic diimide structure, diamines having an amide bond, diamines having a urea bond, and diamines having a group "-N(D)-", and at least one of them. Ar1 and Ar1' each independently represent a benzene ring, a biphenyl structure or a naphthalene ring, and one or more hydrogen atoms on the benzene ring, the biphenyl structure or the naphthalene ring are optionally substituted by a monovalent group, and L1 and L 1’ each independently represent a single bond, -O-, -C(=O)- or -O-C(=O)-, A represents -CH2-, an alkylene group having 2 to 12 carbon atoms or a divalent organic group in which -O-, -C(=O)-O- and -O-C(=O)- are inserted between the carbon-carbon bonds of the alkylene group, and any hydrogen atom possessed by A is optionally substituted by a halogen atom.

7. The liquid crystal aligning agent according to claim 6, wherein, the diamine component contains two or more other diamines.

8. The liquid crystal aligning agent according to claim 6, wherein, the content of the diamine represented by the formula (2) is 90 mol% or less per 1 mol of the diamine component used for manufacturing the polymer P, and the content of the other diamines is 10 to 95 mol% per 1 mol of the diamine component used for manufacturing the polymer P.

9. A liquid crystal alignment film obtained from the liquid crystal aligning agent according to any one of claims 1 to 8.

10. A liquid crystal display element comprising the liquid crystal alignment film according to claim 9.

11. A method for manufacturing a liquid crystal display element, which includes the following steps (1) to (4), Step (1): A step of coating the liquid crystal aligning agent according to any one of claims 1 to 8 on at least one of a first substrate and a second substrate; Step (2): A step of firing the coated liquid crystal aligning agent to obtain a film; Step (3): A step of performing an alignment treatment on the film obtained in step (2); and Step (4): A step of fabricating a liquid crystal cell by disposing a liquid crystal layer between the first substrate and the second substrate in a manner adjacent to the alignment-treated film.

12. The method for manufacturing a liquid crystal display element according to claim 11, wherein, the alignment treatment is a photoalignment treatment.

13. The method for manufacturing a liquid crystal display element according to claim 12, wherein, between step (3) and step (4), a heating treatment step (3b) is further included.

14. The method for manufacturing a liquid crystal display element according to claim 13, wherein, the liquid crystal display element is an in-plane switching (IPS) mode or a fringe field switching (FFS) mode liquid crystal display element.

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