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

Abstract

Provided is a liquid crystal alignment film which suppresses AC afterimage at a high level and which reduces charge accumulation and flicker due to backlight. The liquid crystal aligning agent contains the following polymer (A) and polymer (B). The polymer (A) is selected from the group consisting of polyimide precursors having formula (A1) and polyimides that are imides of the polyimide precursors. The polymer (B) is selected from the group consisting of polyimide precursors of formula (B1) and polyimides that are imides of the polyimide precursors, and the proportion of tetravalent organic groups represented by formula (X-10) is 40 mol% or more with respect to the total of 1 mol of tetracarboxylic acid residues of the polymer (B). # imgabs0 # (wherein the meaning of each symbol in the formula is as defined in the description. ) # imgabs1 # (* represents a bond).

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 devices are widely used as display units of personal computers, smartphones, mobile phones, televisions, and the like. A liquid crystal display device generally includes: a liquid crystal layer sandwiched between a display element substrate and a color filter substrate; a pixel electrode and a common electrode for applying an electric field to the liquid crystal layer; an alignment film for controlling the orientation 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 of liquid crystal molecules, known are longitudinal electric field methods such as TN (Twisted Nematic) method, VA (Vertical Alignment) method, etc.; IPS (In Plane Switching) driving method; transverse electric field methods such as FFS (Fringe Field Switching) driving method, etc.

[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 made of polyamic acid and / or polyimide obtained by imidizing the polyamic acid, using a cloth such as cotton, nylon, polyester. The rubbing treatment is a simple and industrially useful method with excellent productivity. As an alignment treatment method alternative to 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 photoisomerization reaction; methods using a photocrosslinking reaction; methods using a photodecomposition reaction, etc. have been proposed (for example, refer to Non-Patent Document 1, Patent Documents 1, 2, 3).

[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] Patent Document 3: WO2017 / 047596

[0009] Non-Patent Documents

[0010] Non-Patent Document 1: "Functional Materials", November 1997 issue, Vol. 17, No. 11, pages 13 to 22 Summary of the Invention

[0011] Problems to be Solved by the Invention

[0012] In recent years, large-screen and high-definition liquid crystal display elements have become the mainstay. In addition, the popularization of small display terminals such as smart phones, tablet PCs, and car navigation systems is advancing, and the requirement for higher quality of liquid crystal display elements has been further increased compared to the past. In particular, in the liquid crystal alignment films used in liquid crystal display elements represented by the IPS method and the FFS method, 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, after the liquid crystal display element has just been driven, the backlight irradiates the liquid crystal display element. Thus, sometimes charges accumulate inside the liquid crystal display element, and therefore afterimages are generated even during short-term driving. In addition, sometimes problems such as flickering (flicker) occur during driving. This phenomenon significantly reduces the display quality level of the liquid crystal display element, and therefore a liquid crystal alignment film that can obtain a liquid crystal display element without problems such as flickering is sought.

[0013] Therefore, 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 at a higher level than in the past and reduces charge accumulation and flickering caused by the backlight.

[0014] Solutions to the Problems

[0015] The present inventors conducted in-depth research and found that the above technical problems can be solved by using a liquid crystal aligning agent containing specific components, thereby completing the present invention.

[0016] Specifically, the present invention has the following solutions.

[0017] One aspect of the present invention is a liquid crystal aligning agent containing the following polymer (A) and polymer (B).

[0018] Polymer (A): A polymer selected from the group consisting of a polyimide precursor having a repeating unit (a1) represented by the following formula (A1) and a polyimide which is an imidized product of the polyimide precursor.

[0019] Polymer (B): A polymer selected from the group consisting of a polyimide precursor having a repeating unit (b1) represented by the following formula (B1) and a repeating unit (b2) represented by the following formula (B2), and a polyimide which is an imidized product of the polyimide precursor, wherein the proportion of the tetravalent organic group represented by the following formula (X-10) is 40 mol% or more with respect to 1 mol of the total amount of the tetracarboxylic acid residues contained in the polymer (B).

[0020]

[0021] (X1 represents a tetravalent organic group represented by the following formula (X-1). Y1 represents a divalent organic group. R and Z each independently represent a hydrogen atom or a monovalent organic group. A plurality of R and Z each independently have the above definitions.)

[0022]

[0023] (R1 to R4 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group, and at least one of R1 to R4 represents a group other than a hydrogen atom in the above definition. * represents a bonding bond.)

[0024]

[0025] (X 1’ (represents a tetravalent organic group represented by the following formula (X-10). R' and Z' each independently represent a hydrogen atom or a monovalent organic group. A plurality of R' and Z' each independently have the above definitions.)

[0026]

[0027] (X 2’ (represents a tetravalent organic group represented by the following formula (X-10). R' and Z' each independently represent a hydrogen atom or a monovalent organic group. A plurality of R' and Z' each independently have the above definitions.)

[0028]

[0029] (* represents a bonding bond.)

[0030] It should be noted that throughout this specification, the meanings of the following terms and abbreviations are as described below. A halogen atom is a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.

[0031] * represents a bonding bond in any case. In addition, Boc represents tert-butoxycarbonyl, and Fmoc represents 9-fluorenylmethoxycarbonyl.

[0032] Advantages of the Invention

[0033] According to the present invention, a liquid crystal aligning agent, the following liquid crystal alignment film, and a liquid crystal display element using the following liquid crystal alignment film can be provided. The liquid crystal aligning agent can obtain a liquid crystal alignment film that suppresses AC afterimages at a higher level than before and reduces charge accumulation and flicker caused by a backlight.

[0034] The mechanism by which the present invention achieves the above effects is not necessarily clear, but the following is considered to be one of the reasons. It is considered that by improving the intermolecular packing property, the physical stability of the aligning agent due to the AC afterimage characteristics is improved, and further by increasing the density of π-conjugated system molecules, the charge transfer is promoted, the charge accumulation and the resulting flicker are suppressed, and thus the above effects are obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 FIG. is a schematic cross-sectional view of an example of a transverse electric field liquid crystal display element including a liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention.

[0036] Figure 2 FIG. is a schematic cross-sectional view of another example of a transverse electric field liquid crystal display element including a liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0037] <Polymer (A)>

[0038] The liquid crystal aligning agent of the present invention contains a polymer (A) selected from the group consisting of a polyimide precursor having a repeating unit (a1) represented by the above formula (A1) and a polyimide which is an imidized product of the polyimide precursor.

[0039] It should be noted that the polymer (A) contained in the liquid crystal aligning agent may be composed of one or two or more polymers.

[0040] In addition, the repeating unit constituting the polymer (A) may be one repeating unit, or two, three, or four or more different repeating units.

[0041] Examples of the monovalent organic group in R and Z in the above formula (A1) include: a monovalent hydrocarbon group having 1 to 20 carbon atoms, and a methylene group in the hydrocarbon group is replaced by -O-, -S-, -CO-, -COO-, -COS-, -NR 3 -, -CO-NR 3 -, -Si(R 3 )2-, -SO2-, etc. substituted monovalent group A (wherein, R 3 is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, and when there are a plurality of R 3 , each R 3(which may be the same or different); at least one of the hydrogen atoms bonded to the carbon atom of the monovalent hydrocarbon group or the monovalent group A is replaced by a halogen atom, a hydroxyl group, an alkoxy group, a nitro group, an amino group, a mercapto group, a nitroso group, an alkylsilyl group, an alkoxysilyl group, a silanol group, a sulfino group, a phosphino group, a carboxyl group, a cyano group, a sulfo group, an acyl group, etc.; a monovalent group having a heterocyclic ring; etc. As the monovalent organic group in R and Z in the above formula (A1), an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, Boc or Fmoc is preferred, and an alkyl group having 1 to 3 carbon atoms is more preferred, and methyl is even more preferred.

[0042] From the viewpoint of appropriately obtaining the effects of the present invention, R and Z are each independently preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom or a methyl group.

[0043] Specific examples of the alkyl group having 1 to 6 carbon atoms in R1 to R4 in the above formula (X-1) include: methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, etc.

[0044] Specific examples of the alkenyl group having 2 to 6 carbon atoms in R1 to R4 include: vinyl, propenyl, butenyl, etc., and these groups can be linear or branched.

[0045] Specific examples of the alkynyl group having 2 to 6 carbon atoms in R1 to R4 include: ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, etc.

[0046] Specific examples of the monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom in R1 to R4 include: fluoromethyl, trifluoromethyl, trifluoromethoxy, 2,2,2-trifluoroethyl, 2,2,2-trifluoroethoxy, pentafluoroethyl, pentafluoropropyl, etc.

[0047] In the above formula (X-1), a structure selected from the group consisting of the following formulas (x1-1) to (x1-5) is preferred.

[0048]

[0049] Specific examples of the divalent organic group Y1 include a divalent organic group derived from a diamine (hereinafter, also referred to as specific diamine (a)) having a structure of -N(Z)-Y1-N(Z)- (the definitions of Y1 and Z are the same as above).

[0050] It should be noted that the divalent organic group derived from a diamine means an organic group existing between the two amino groups of the diamine.

[0051] As specific examples of the above-mentioned specific diamine (a), for example, diamine H-N(Z)-Y1-N(Z)-H (where Y1 and Z each represent the above definitions) can be cited.

[0052] As the specific diamine (a) that provides Y1 in the above formula (A1), the following preferred specific examples are cited, but are not limited thereto.

[0053] p-Phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, m-phenylenediamine, 2,4-dimethyl-m-phenylenediamine, 2,5-diaminotoluene or 2,6-diaminotoluene and other phenylenediamines and their derivatives; 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, or 2,3'-diaminobiphenyl and other biphenyldiamines and their derivatives; the diamine represented by the following formula (d AL ) (preferably the diamine represented by the following formula (d AL -1) to (d AL-12), 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; diamines having a pyromellitimide structure such as 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; diamines having a photo-orienting group such as diamines represented by the following formulas (g-1) to (g-9); 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 radical polymerization initiator function such as 1-(4-(2-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylpropanone, 2-(4-(2-hydroxy-2-methylpropanoyl)phenoxy)ethyl 3,5-diaminobenzoate; diamines having a urea bond such as diamines represented by the following formulas (u-1) to (u-3) (wherein the diamine does not have a carbamate-based protecting group in the molecule); diamines having an amide bond such as diamines represented by the following formulas (u-4) to (u-7) (wherein the diamine does not have a carbamate-based protecting group in the molecule);4,4'-Diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 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) or a diamine having a diphenylamine structure such as 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl-N-methylamine, N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine or N,N'-bis(4-aminophenyl)-N,N'-dimethyl-1,4-benzenediamine, which has 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. In this case, the specific nitrogen atom-containing structure is a group other than the two amino groups participating in the polycondensation reaction); 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 4,4'-diamino-3,3'-dihydroxybiphenyl;Diamines having a carboxyl group such as 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, or 4,4'-diaminodiphenyl ether-3,3'-dicarboxylic acid; semi-aromatic diamines having a primary amino group and a secondary amino group (preferably 4-(2-(methylamino)ethyl)aniline) (wherein, the semi-aromatic diamine means a diamine in which one amino group is bonded to an aromatic ring and the other amino group is not bonded to an aromatic ring); semi-aromatic diamines having two primary amino groups (preferably 4-(2-aminoethyl)aniline or 2-(6-amino-2-naphthyl)ethylamine); 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)-" (D represents a protecting group that is removed by heating and replaced with a hydrogen atom, preferably a carbamate-based protecting group, more preferably Boc) such as 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, lanosteryl 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); diamines having a siloxane bond such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane; m-xylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), diamines formed by bonding two amino groups to a group represented by any one of the formulas (Y-1) to (Y-167) described in WO2018 / 117239, etc.;

[0054]

[0055] (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 with a monovalent group. L1 and L 1’Each independently represents a single bond, -O-, -C(=O)- or -O-C(=O)-. A represents -CH2-, an alkylene group having 2 to 12 carbon atoms, or a divalent organic group 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. Any hydrogen atom possessed by A is optionally substituted by a halogen atom.

[0056] One or more hydrogen atoms on the above 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 alkyloxycarbonyl group having 2 to 3 carbon atoms, a cyano group, a nitro group, etc.)

[0057]

[0058] (In formula (d AL -6), the sum of m1, m2 and n is 1 to 12. In formula (d AL -8), the sum of m1, m2 and n is 3 to 12.

[0059] In formula (d AL -11) and (d AL -12), the sum of m1, m2 and n is 3 to 12.)

[0060]

[0061]

[0062]

[0063] (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-.

[0064] R 1 represents a fluorine atom, a fluorine atom-containing alkyl group having 1 to 10 carbon atoms, a fluorine atom-containing alkoxy 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 an alkoxyalkyl group having 2 to 10 carbon atoms, etc., as monovalent groups.

[0065] In the above formula (V-2), X 2It represents -O-, -CH2O-, -CH2-OCO-, -COO- or -OCO-. In the case where there are two m, n, X 1 , R 1 , they each independently have the above definitions.)

[0066] From the viewpoint of appropriately obtaining the effects of the present invention, the polymer (A) is preferably at least one polymer selected from the group consisting of a polyimide precursor and a polyimide which is an imidized product of the polyimide precursor, the polyimide precursor containing a repeating unit in which the above Y1 has a divalent organic group derived from a diamine, and the diamine being: phenylenediamine and its derivatives, biphenylenediamine and its derivatives, the diamine represented by the above formula (d AL ), the diamine having a tetracarboxylic diimide structure, the diamine having a photo-orienting group, the diamine having a urea bond, the diamine having an amide bond, a diamine having a structure containing at least one nitrogen atom selected from the group consisting of a nitrogen atom-containing heterocycle, a secondary amino group, and a tertiary amino group, the semi-aromatic diamine having a primary amino group and a secondary amino group, the semi-aromatic diamine having two primary amino groups, or the diamine having the group "-N(D)-".

[0067] From the viewpoint of appropriately obtaining the effects of the present invention, for the polymer (A), the total of the repeating unit (a1) and the imidized structural unit of the repeating unit (a1) is preferably 5 to 100 mol%, more preferably 10 to 100 mol%, of all the repeating units possessed by the polymer (A).

[0068] It should be noted that in this total, the case where either the repeating unit (a1) or the imidized structural unit of the repeating unit (a1) is 0 mol% is also included. In the following, when also referred to as the total, the case where one or more of the constituent elements is 0 mol% is also included.

[0069] In the case where the polymer (A) contains repeating units other than the repeating unit (a1) and / or the imidized structural unit of the repeating unit (a1), it is preferable that the total of the repeating unit (a1) and the imidized structural unit of the repeating unit (a1) is 95 mol% or less, more preferably 90 mol% or less, of all the repeating units possessed by the polymer (A).

[0070] From the viewpoint of appropriately obtaining the effects of the present invention, for the polymer (A), the proportion of the tetravalent organic group represented by the above formula (X-1) is preferably 50 mol% or more, more preferably 70 mol% or more, further preferably 80 mol% or more, and most preferably 90 mol% or more, relative to 1 mol of the total of the tetracarboxylic acid residues contained in the polymer (A).

[0071] Here, the tetracarboxylic acid residue contained in the polymer (A) represents a tetravalent organic group between four carbonyl groups possessed by, for example, a tetracarboxylic dianhydride or its derivative (e.g., tetracarboxylic acid, tetracarboxylic dihalide, dialkyl tetracarboxylate, or dialkyl tetracarboxylate dihalide, etc.) used for synthesizing the polymer (A).

[0072] The above polymer (A) can be a polymer selected from the group consisting of a polyimide precursor having a repeating unit (a1) represented by the above formula (A1) and further having a repeating unit (a2) represented by the following formula (A2), and a polyimide which is an imidized product of the polyimide precursor. It should be noted that the repeating unit (a2) can be composed of one or two or more repeating units.

[0073]

[0074] In the above formula (A2), R has the same meaning as R in the above formula (A1), and Z has the same meaning as Z in the above formula (A1).

[0075] X2 represents a tetravalent organic group other than the tetravalent organic group represented by the above formula (X - 1), and Y2 represents a divalent organic group.

[0076] Specific examples of the tetravalent organic group other than the tetravalent organic group represented by the above formula (X - 1) include other tetravalent tetracarboxylic acid residues other than the tetravalent organic group represented by the above formula (X - 1).

[0077] Specific examples of other tetravalent tetracarboxylic acid residues include tetravalent tetracarboxylic acid residues derived from an alicyclic tetracarboxylic dianhydride, an acyclic aliphatic tetracarboxylic dianhydride, an aromatic tetracarboxylic dianhydride, or a derivative of these substances other than the tetravalent organic group represented by the above formula (X - 1).

[0078] Among the above alicyclic tetracarboxylic dianhydrides, aromatic tetracarboxylic dianhydrides, or derivatives of these substances, 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 is more preferred.

[0079] 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 does not need 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.

[0080] 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 does not need 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.

[0081] An aromatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an aromatic ring. Among them, it does not need to be composed only of an aromatic ring structure, and a chain hydrocarbon structure or an alicyclic structure may be present in a part thereof.

[0082] From the viewpoint of appropriately obtaining the effects of the present invention, X2 in the above formula (A2) may be exemplified by a tetravalent organic group represented by any one of the following formulas (X-2) to (X-27), the following formulas (Xa-1) to (Xa-2), or the following formulas (Xr-1) to (Xr-7).

[0083] From the viewpoint of appropriately obtaining the effects of the present invention, X2 in the above formula (A2) is more preferably a tetravalent organic group represented by any one of the following formulas (X-2) to (X-12).

[0084]

[0085] (In the formulas (Xa-1) and (Xa-2), x and y are each independently a single bond, -O-, -C(=O)-, -C(=O)-O-, -O-C(=O)-, an alkanediyl having 1 to 10 carbon atoms, 1,4-phenylene, -S(=O)2-, or -C(=O)-NR- (R is a hydrogen atom or a methyl group). j and k are 0 or 1. When there are a plurality of y's, they may be the same or different from each other.)

[0086]

[0087] The tetravalent organic group represented by the above formula (Xa-1) or (Xa-2) may be a structure represented by any one of the following formulas (Xa-3) to (Xa-19).

[0088]

[0089] As a specific example of Y2 in the above formula (A2), for example, a structure exemplified by the divalent organic group Y1 of the above formula (A1) can be cited.

[0090] From the viewpoint of appropriately obtaining the effects of the present invention, for the polymer (A), the total of the imidized structural units of the repeating unit (a2) and the repeating unit (a2) is preferably 5 mol% or more, more preferably 10 mol% or more, of all the repeating units of the polymer (A).

[0091] In addition, for the polymer (A), the total of the imidized structural units of the repeating unit (a2) and the repeating unit (a2) is preferably 95 mol% or less, more preferably 90 mol% or less, of all the repeating units of the polymer (A).

[0092] From the viewpoint of appropriately obtaining the effects of the present invention, the polymer (A) is more preferably a polymer selected from the group consisting of a polyimide precursor and a polyimide which is an imidized product of the polyimide precursor, the polyimide precursor containing a repeating unit having a divalent organic group derived from a diamine, and the diamine being: phenylenediamine and its derivatives, biphenylenediamine and its derivatives, the diamine represented by the above formula (d AL ), the diamine having a tetracarboxylic diimide structure, the diamine having a photo-aligning group, the diamine having a urea bond, the diamine having an amide bond, the diamine having a nitrogen atom-containing structure, the semi-aromatic diamine having a primary amino group and a secondary amino group, the semi-aromatic diamine having two primary amino groups, or the diamine having the group “-N(D)-”.

[0093] <Polymer (B)>

[0094] The liquid crystal aligning agent of the present invention contains the following polymer, which is a polymer (B) selected from the group consisting of a polyimide precursor having a repeating unit (b1) represented by the above formula (B1) and a repeating unit (b2) represented by the above formula (B2), and a polyimide which is an imidized product of the polyimide precursor, wherein the proportion of the tetravalent organic group represented by the above formula (X-10) is 40 mol% or more relative to 1 mol of the total of the tetracarboxylic acid residues contained in the polymer (B).

[0095] The polymer (B) is a polymer different from the above polymer (A).

[0096] The proportion of the tetravalent organic group represented by the above formula (X-10) is preferably 50 mol% or more, more preferably 60 mol% or more relative to 1 mol of the total of the tetracarboxylic acid residues contained in the polymer (B).

[0097] Herein, the tetracarboxylic acid residue contained in the polymer (B) represents a tetravalent organic group existing between four carbonyl groups of the tetracarboxylic dianhydride or its derivative used for synthesizing the polymer (B).

[0098] From the viewpoint of appropriately obtaining the effects of the present invention, for the polymer (B), the total of the repeating unit (b1), the repeating unit (b2), and the imidized structural units of these substances is preferably 20 to 100 mol%, more preferably 40 to 100 mol% of all the repeating units possessed by the polymer (B).

[0099] The total proportion of the divalent organic groups represented by 1,3-phenylene in the above formula (B2) and 1,4-phenylene in the above formula (B1) is more preferably 60 mol% or more, still more preferably 80 mol% or more, relative to 1 mol of the total divalent organic groups derived from the diamines contained in the polymer (B).

[0100] The proportion of the divalent organic group represented by 1,4-phenylene in the above formula (B1) is more preferably 40 mol% or more, still more preferably 50 mol% or more, relative to 1 mol of the total divalent organic groups derived from the diamines contained in the polymer (B).

[0101] The proportion of the divalent organic group represented by 1,3-phenylene in the above formula (B2) is more preferably 5 mol% or more, still more preferably 10 mol% or more, relative to 1 mol of the total divalent organic groups derived from the diamines contained in the polymer (B).

[0102] Among them, both ends of the above 1,3-phenylene or 1,4-phenylene are bonded to nitrogen atoms.

[0103] It should be noted that the divalent organic groups derived from the diamines contained in the polymer (B) refer to the organic groups existing between the two amino groups of the diamines or their derivatives used for synthesizing the polymer (B).

[0104] As specific examples of the monovalent organic groups in R' and Z' in the above formulas (B1) and (B2), the structures exemplified by the monovalent organic groups in R and Z in the above formula (A1) can be cited.

[0105] The preferred embodiments of R' and Z' in the above formulas (B1) and (B2) are the same as those of R and Z in the above formula (A1).

[0106] From the viewpoint of appropriately obtaining the effects of the present invention, the above polymer (B) can be a polymer selected from the group consisting of a polyimide precursor having the above repeating unit (b1), repeating unit (b2), and imidized structural units of these substances and further having a repeating unit (b3) represented by the following formula (B3), and a polyimide which is an imidized product of the polyimide precursor. It should be noted that the repeating unit (b3) can be composed of one or two or more repeating units.

[0107]

[0108] In the above formula (B3), R' has the same meaning as R' in the above formula (B1), and Z' has the same meaning as Z' in the above formula (B1).

[0109] X 3’ represents a tetravalent organic group, Y 3’represents a divalent organic group and satisfies either of the following conditions (1) or (2).

[0110] (1) In Y 3’ When X represents a divalent organic group represented by 1,3-phenylene or 1,4-phenylene, 3’ represents a tetravalent organic group other than the tetravalent organic group represented by the above formula (X-10).

[0111] (2) In Y 3’ When X represents a divalent organic group other than 1,3-phenylene or 1,4-phenylene, 3’ represents a tetravalent organic group.

[0112] As X in (2) above 3’ Specific examples of the tetravalent organic group include the same tetravalent organic group as X1 in the above formula (A1) or the same tetravalent organic group as X2 in the above formula (A2).

[0113] From the viewpoint of appropriately obtaining the effects of the present invention, X 3’ The tetravalent organic group is preferably a tetracarboxylic dianhydride derived from the above-mentioned non-aliphatic or alicyclic tetracarboxylic dianhydride or a derivative thereof. The tetravalent organic group derived from alicyclic tetracarboxylic dianhydride or a derivative thereof is preferably a tetracarboxylic dianhydride 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.

[0114] More preferably X 3’ It is a tetravalent organic group represented by any of the above formulae (X-1) to (X-15).

[0115] When the polymer (B) has a tetravalent organic group other than the tetravalent organic group represented by the above formula (X-10), the ratio of the tetravalent organic group other than the tetravalent organic group represented by the above formula (X-10) is preferably 60 mol% or less, more preferably 50 mol% or less, and even more preferably 40 mol% or less, relative to 1 mol of the total tetracarboxylic acid residues contained in the polymer (B). Furthermore, the ratio of the tetravalent organic group other than the tetravalent organic group represented by the above formula (X-10) is preferably 1 mol% or more, more preferably 5 mol% or more, relative to 1 mol of the total tetracarboxylic acid residues contained in the polymer (B).

[0116] Examples of the divalent organic group other than 1,3-phenylene or 1,4-phenylene in the above-mentioned (2) include divalent organic groups derived from other diamines (3') other than the diamine H-N(Z')-Y'-N(Z')-H (Y' represents 1,3-phenylene or 1,4-phenylene, and the definition of Z' is the same as that of the above-mentioned formula (B3)).

[0117] It should be noted that the divalent organic group derived from other diamines (3') refers to the organic group existing between the two amino groups of the diamine.

[0118] Other diamines (3') can be represented, for example, by the diamine H-N(Z')-Y 3’ -N(Z')-H (Y 3’ represents a divalent organic group other than 1,3-phenylene or 1,4-phenylene, and Z' represents the above-defined group).

[0119] As preferred specific examples of the above other diamines (3'), for example, compounds exemplified by the specific examples of the above specific diamine (a) other than m-phenylenediamine and p-phenylenediamine can be cited.

[0120] From the viewpoint of appropriately obtaining the effects of the present invention, the polymer (B) is preferably a polymer selected from the group consisting of a polyimide precursor and a polyimide which is an imidized product of the polyimide precursor, and the polyimide precursor contains Y 3’ and has a repeating unit having a divalent organic group derived from a diamine (collectively also referred to as a specific divalent organic group (b)), and the diamine is: the above diamine having a urea bond, the above diamine having an amide bond, or the above diamine having a nitrogen atom-containing structure, the above semi-aromatic diamine having a primary amino group and a secondary amino group, or a semi-aromatic diamine having two primary amino groups.

[0121] The polymer (B) is more preferably a polymer selected from the group consisting of the following combinations (pb1) to (pb2). It should be noted that in the following schemes, the terminals of the polymer are optionally capped.

[0122] (pb1): A polymer selected from the group consisting of a polyimide precursor containing the above repeating unit (b1) and the above repeating unit (b2) and a polyimide which is an imidized product of the polyimide precursor.

[0123] (pb2): A polymer selected from the group consisting of a polyimide precursor containing the above repeating unit (b1), the above repeating unit (b2), and the above repeating unit (b3) and a polyimide which is an imidized product of the polyimide precursor.

[0124] From the viewpoint of appropriately obtaining the effects of the present invention, for the polymer (B), the proportion of the above specific divalent organic group (b) is preferably 1 mol% or more, more preferably 5 mol% or more, relative to 1 mol of the total of the divalent organic groups derived from the diamines contained in the polymer (B).

[0125] In addition, the proportion of the above specific divalent organic group (b) is preferably 40 mol% or less, more preferably 20 mol% or less, relative to 1 mol in total of the divalent organic groups derived from the diamines contained in the polymer (B).

[0126] From the viewpoint of less afterimage derived from the residual DC, the mass ratio of the content of the polymer (A) to the content of the polymer (B) (content of the polymer (A) / content of the polymer (B)) is preferably 10 / 90 to 90 / 10, more preferably 20 / 80 to 90 / 10, and still more preferably 20 / 80 to 80 / 20.

[0127] <Manufacturing methods of the polymer (A) and the polymer (B)>

[0128] In the present invention, polyimide precursors (such as polyamide acid esters and polyamic acids) in the polymer (A) and the polymer (B), and polyimides which are imidized products of these polyimide precursors can be synthesized, for example, by known methods described in WO2013 / 157586.

[0129] Specifically, it is synthesized by reacting a diamine component and a tetracarboxylic acid derivative component in a solvent (polycondensation reaction). Examples of the above tetracarboxylic acid derivative component include tetracarboxylic dianhydrides or their derivatives (tetracarboxylic dihalides, tetracarboxylic diesters or tetracarboxylic diester dihalides). When a part of the polymer (A) and the polymer (B) contains an amic acid structure, for example, by reacting a tetracarboxylic dianhydride component and a diamine component, a polymer having an amic acid structure (polyamic acid) can be obtained. The solvent is not particularly limited as long as the resulting polymer is soluble therein.

[0130] Specific examples are listed. The diamine component and the tetracarboxylic acid derivative component for obtaining the polyimide precursor of the polymer (A) are each selected and used in such a way as to obtain the structure of the repeating unit represented by the above formulas (A1) and (A2) possessed by the polymer (A).

[0131] For example, in the case of having the repeating unit represented by the formula (A1) possessed by the polymer (A), as the diamine component, a specific diamine (a) is used, and in addition, as the tetracarboxylic acid derivative component, a tetracarboxylic acid derivative having the above structure of X1 is used.

[0132] Specific examples of the above solvent when reacting a diamine component and a tetracarboxylic acid derivative component include: 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, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, and H3C-CH(OH)-CH2-O-D 1 (D 1 represents an alkyl group having 1 to 3 carbon atoms), HO-CH2-CH2-O-D 2 (D 2 represents an alkyl group having 1 to 3 carbon atoms) or HO-CH2-CH2-O-CH2-CH2-O-D 3 (D 3 represents an alkyl group having 1 to 4 carbon atoms) can be used as the solvent.

[0133] As specific examples of the above solvents represented by H3C-CH(OH)-CH2-O-D 1 , HO-CH2-CH2-O-D 2 , HO-CH2-CH2-O-CH2-CH2-O-D 3 include: propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, etc.

[0134] These solvents can be used alone or in combination. Moreover, even solvents that do not dissolve the polymer can be used in combination with the above solvents within the range where the formed polymer does not precipitate.

[0135] When reacting the diamine component and the tetracarboxylic acid derivative component in a solvent, the reaction can be carried out at any concentration. The solvent is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. It is also possible to carry out the reaction at a high concentration in the initial stage and then add the solvent later.

[0136] In the reaction, the ratio of the total molar amount of the diamine component to the total molar amount of the tetracarboxylic acid derivative component (total molar amount of the tetracarboxylic acid derivative component / total molar amount of the diamine component) is preferably 0.8 to 1.2. Similar to the usual polycondensation reaction, the closer this molar ratio is to 1.0, the larger the molecular weights of the resulting polymers (A) and (B).

[0137] Polyamide esters can be obtained, for example, by the following known methods:

[0138] [I] A method of reacting the polyamic acid obtained by the above method with an esterifying agent.

[0139] [II] Method for reacting a dicarboxylic acid diester with a diamine.

[0140] [III] Method for reacting a dicarboxylic acid diester dihalide with a diamine, etc.

[0141] As a method for obtaining a polyimide, there can be mentioned: thermal imidization in which a solution containing a polyimide precursor such as polyamic acid or polyamic acid ester obtained in the above reaction is heated while maintaining this state, or catalytic imidization in which a catalyst is added to the above solution.

[0142] In the polyimide in the polymer (A) and polymer (B) of the present invention, a part or all of the repeating units possessed by the above polyimide precursor are cyclized. In the above polyimide, the imidization rate is preferably 20 to 95%, more preferably 30 to 95%, and still more preferably 50 to 95%.

[0143] <Solution viscosity and molecular weight of the polymer>

[0144] When a solution of the polyimide precursor and polyimide in the polymer (A) and polymer (B) of the present invention is made into a solution with a concentration of 10 to 15% by mass, for example, from the viewpoint of workability, it is preferably maintained at a solution viscosity of 10 to 1000 mPa·s, but there is no particular limitation. It should be noted that the solution viscosity (mPa·s) of the above polymer is a value measured at 25°C using an E-type rotational viscometer for a polymer solution with a concentration of 10 to 15% by mass prepared using a good solvent for the polymer (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0145] The polystyrene-reduced weight-average molecular weight (Mw) of the above polyimide precursor and polyimide measured by gel permeation chromatography (GPC) is preferably 1000 to 500000, more preferably 2000 to 300000. 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 within this molecular weight range, good alignment and stability of the liquid crystal display element can be ensured.

[0146] <End-capping agent>

[0147] When synthesizing the polymer (A) and polymer (B) in the present invention, an appropriate end-capping agent can also be used together with the above-mentioned tetracarboxylic acid derivative component and diamine component to synthesize an end-capped polymer. The end-capped polymer has the effect 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.

[0148] Examples of the ends of polymer (A) and polymer (B) in the present invention include: amino group, carboxyl group, acid anhydride group or their derivatives. The amino group, carboxyl group, and acid anhydride group can be obtained by ordinary condensation reactions or by end-capping with the following end-capping agents. For example, they can be obtained in the same manner by using the following end-capping agents.

[0149] Examples of the end-capping agents include: acid anhydrides such as acetic anhydride, maleic anhydride, nadic anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, 3-(3-trimethoxysilyl)propyl-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, 4-ethynylphthalic anhydride; dicarbonate diester compounds such as di-tert-butyl dicarbonate, diallyl dicarbonate; chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride, nicotinoyl chloride; 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; monoisocyanate compounds such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate, 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate having an unsaturated bond; isothiocyanate compounds such as ethyl isothiocyanate, allyl isothiocyanate, etc.

[0150] The use ratio of the end-capping agent is preferably 0.01 to 20 mol parts, more preferably 0.01 to 10 mol parts, based on 100 mol parts in total of the diamine components used.

[0151] <Liquid crystal aligning agent>

[0152] The liquid crystal aligning agent of the present invention contains polymer (A) and polymer (B) as required. In addition to containing polymer (A) and polymer (B), the liquid crystal aligning agent of the present invention may further contain other polymers. Specific examples of other polymers include polymers selected from the group consisting of polysiloxane, polyester, polyamide, polyurea, polyurethane, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene derivative, poly(styrene-maleic anhydride) copolymer, poly(isobutene-maleic anhydride) copolymer, poly(vinyl ether-maleic anhydride) copolymer, poly(styrene-phenylmaleimide) derivative, poly(meth)acrylate.

[0153] As specific examples of the poly(styrene - maleic anhydride) copolymer, the following can be cited: SMA1000, 2000, 3000 (manufactured by Cray Valley), GSM301 (manufactured by Gifu Shellac Manufacturing), etc. As specific examples of the poly(isobutylene - maleic anhydride) copolymer, ISOBAM - 600 (manufactured by Kuraray) can be cited. As specific examples of the poly(vinyl ether - maleic anhydride) copolymer, Gantrez AN - 139 (methyl vinyl ether maleic anhydride resin, manufactured by Ashland) can be cited. Other polymers can be used alone or in combination of two or more.

[0154] The content ratio of other polymers is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, and further preferably 50 parts by mass or less, based on 100 parts by mass in total of the polymers contained in the liquid crystal aligning agent. In addition, it is preferably 0.1 part by mass or more, more preferably 1 part by mass or more.

[0155] The liquid crystal aligning agent is used to form a liquid crystal alignment film and is in the form of a coating solution from the viewpoint of forming a uniform thin film. In the liquid crystal aligning agent of the present invention, a coating solution containing the above polymer component and an organic solvent is also preferred. At this time, the concentration of the polymer in the liquid crystal aligning agent can be appropriately changed according to the thickness of the coating film to be formed. From the aspect of forming a uniform and defect - free coating film, the concentration of the polymer is preferably 1% by mass or more, and from the aspect of the storage stability of the solution, the concentration of the polymer is preferably 10% by mass or less. The particularly preferred concentration of the polymer is 2 - 8% by mass.

[0156] From the viewpoint of appropriately obtaining the effects of the present invention, the total content of polymer (A) and polymer (B) in the liquid crystal aligning agent is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and further preferably 50 parts by mass or more, based on 100 parts by mass in total of the polymer components contained in the liquid crystal aligning agent.

[0157] When the liquid crystal aligning agent contains the above - mentioned other polymers, the total content of polymer (A) and polymer (B) is preferably 99.9 parts by mass or less, more preferably 99 parts by mass or less, based on 100 parts by mass in total of the polymers contained in the liquid crystal aligning agent.

[0158] The organic solvent contained in the liquid crystal aligning agent is not particularly limited as long as it can uniformly dissolve the polymer component. Specific 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"). 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.

[0159] 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 that improves the coatability and the surface smoothness of the coating film when coating the liquid crystal aligning agent (also called a poor solvent) is used. 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.

[0160] Specific examples of the above poor solvents are described below, but are not limited to these poor solvents.

[0161] Examples include: diisopropyl ether, diisobutyl ether, diisobutyl carbinol (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, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monopropyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol acetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, cyclohexyl acetate, 4-methyl-2-pentyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, diisobutyl ketone (2,6-dimethyl-4-heptanone), etc.

[0162] As a poor solvent, preferably, diisobutyl carbinol, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate or diisobutyl ketone.

[0163] Examples of preferred combinations of solvents as good solvents and poor solvents include: N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, and ethylene glycol monobutyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether; N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone; N-ethyl-2-pyrrolidone and propylene glycol diacetate; N,N-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, diacetone alcohol cyclohexanone, and propylene glycol monomethyl ether; cyclopentanone and propylene glycol monomethyl ether; N-methyl-2-pyrrolidone, cyclohexanone, and propylene glycol monomethyl ether, etc.;

[0164] The liquid crystal aligning agent of the present invention may also additionally contain components other than the polymer component and the organic solvent (hereinafter, also referred to as additive components). Examples of such additive components include: adhesion aids for improving the adhesion between the liquid crystal alignment film and the substrate and between the liquid crystal alignment film and the sealant; compounds for improving the strength of the liquid crystal alignment film (hereinafter, also referred to as crosslinkable compounds); compounds for promoting imidization; dielectrics or conductive substances for adjusting the dielectric constant and resistance of the liquid crystal alignment film, etc.

[0165] As the above-mentioned adhesion aids, for example, 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, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, 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 and other silane coupling agents.

[0166] From the viewpoint of appropriately obtaining the effects of the present invention, when using a silane coupling agent, it 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.

[0167] From the viewpoint of appropriately obtaining the effects of the present invention, as the above-mentioned crosslinkable compound, at least one compound selected from the group consisting of a crosslinkable compound having a substituent and a crosslinkable compound having a polymerizable unsaturated group can be cited, wherein the substituent is selected from at least one of an epoxy group, an isocyanate group, an oxetanyl group, a blocked isocyanate group, an oxazolinyl group, a cyclic carbonate group, a mesityl oxide structure, a hydroxyl group, and an alkoxy group.

[0168] As preferable specific examples of the above crosslinkable compounds, the following can be mentioned: 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 Corporation), bisphenol F type epoxy resins such as EPIKOTE 807 (manufactured by Mitsubishi Chemical Corporation), hydrogenated bisphenol A type epoxy resins such as YX - 8000 (manufactured by Mitsubishi Chemical Corporation), epoxy resins containing a biphenyl skeleton such as YX6954BH30 (manufactured by Mitsubishi Chemical Corporation), phenol novolac type epoxy resins such as EPPN - 201 (manufactured by Nippon Kayaku Co., Ltd.), (ortho, meta, para -) cresol novolac type epoxy resins such as EOCN - 102S (manufactured by Nippon Kayaku Co., Ltd.), triglycidyl isocyanurate 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 oxetanyl groups described in paragraphs 0170 to 0175 of WO2011 / 132751; compounds having two or more blocked isocyanate groups described in paragraphs 0046 to 0047 of JP - A - 2014 - 224978; compounds having three or more blocked isocyanate groups described in paragraphs 0119 to 0120 of WO2015 / 141598 (preferably CORONATE AP stable M, CORONATE2503, 2515, 2507, 2513, 2555, MILLIONATE MS - 50 (above, manufactured by TOSOH Corporation), TAKENATE B - 830, B - 815N, B - 820NSU, B - 842N, B - 846N, B - 870N, B - 874N, B - 882N (above, manufactured by Mitsui Chemicals, Inc.)) and other compounds having a blocked isocyanate group;The compounds containing two or more oxazoline groups (preferably 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, EPOCROS (manufactured by Nippon Shokubai Co., Ltd.), etc.) having an oxazoline group as described in Paragraph 0115 of JP-A-2007-286597; the compounds having a cyclic carbonate group as described in Paragraphs 0025 to 0030 and 0032 of WO2011 / 155577; the compounds having two or more Meldrum's acid structures as described in WO2012 / 091088; the compounds having a hydroxyl group and an alkoxy group 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; the compounds represented by glycerol mono(meth)acrylate, glycerol di(meth)acrylate (1,2-, 1,3-type mixture), 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.;

[0169] The content of the above crosslinkable compound is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, based on 100 parts by mass of the polymer component contained in the liquid crystal aligning agent.

[0170] As the compound for promoting imidization described above, a compound having a basic site (e.g., primary amino group, aliphatic heterocycle (e.g., pyrrolidine skeleton), aromatic heterocycle (e.g., imidazole ring, indole ring), or guanidyl group, etc.) is preferred (wherein, the above crosslinkable compound and adhesion promoter are not included); or a compound that generates the above basic site during firing. A compound that generates the above basic site during firing is more preferred. If specific preferred examples are listed, amino acids in which a part or all of the basic sites possessed by the amino acids are protected can be listed. As the protecting group for the basic site possessed by the above amino acids, carbamate-based protecting groups such as Boc can be listed. Specific examples of the above amino acids include: glycine, alanine, cysteine, methionine, asparagine, glutamic acid, valine, leucine, phenylalanine, tyrosine, tryptophan, proline, hydroxyproline, arginine, histidine, lysine, ornithine. If more specific preferred examples of the compound for promoting imidization are listed, N-α-(9-fluorenylmethoxycarbonyl)-N-τ-(tert-butoxycarbonyl)-L-histidine can be listed.

[0171] The content of the above compound for promoting imidization contained in the liquid crystal aligning agent of the present invention is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, and further preferably 5 to 20 parts by mass with respect to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent.

[0172] The solid content concentration in the liquid crystal aligning agent of the present invention (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 in the range of 1 to 10% by mass.

[0173] 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. As described in the subsequent step (1), as the method of coating the liquid crystal aligning agent on the substrate, for example, a roll coater method, a spin coating method, a printing method, an inkjet method, etc. can be listed. In the case of using the roll coater method, the solid content concentration is particularly preferably in the range of 4 to 10% by mass. In the case of using the spin coating method, the solid content concentration is particularly preferably in the range of 1.5 to 4.5% by mass. In the case of using the printing method, the solid content concentration is particularly preferably set in the range of 3 to 9% by mass, thereby setting the solution viscosity in the range of 12 to 50 mPa·s. In the case of using the inkjet method, the solid content concentration is particularly preferably set in the range of 1 to 5% by mass, thereby setting the solution viscosity in the range of 3 to 15 mPa·s. The temperature during the preparation of the liquid crystal aligning agent is preferably 10 to 50 °C, and more preferably 20 to 30 °C.

[0174] <Liquid crystal alignment film>

[0175] The liquid crystal alignment film of the present invention is obtained from the above liquid crystal aligning agent. The liquid crystal alignment film of the present invention can be used for a liquid crystal alignment film in a horizontal alignment mode or a vertical alignment mode (VA mode), wherein the liquid crystal alignment film is a liquid crystal alignment film suitable for a liquid crystal display element in a horizontal alignment mode such as an IPS driving mode or an FFS driving mode. In addition, it is more preferably used for a liquid crystal alignment film for a photo-alignment treatment method. In addition, the liquid crystal alignment film can be effectively applied to various technical uses, for example, it can also be applied to a liquid crystal alignment film other than the above uses (a liquid crystal alignment film for a retardation film, a scanning antenna, a liquid crystal array antenna, or a liquid crystal alignment film for a transmissive scattering type liquid crystal dimming element).

[0176] The liquid crystal alignment film of the present invention can be manufactured, for example, by a method including the following steps (1) to (3).

[0177] <Step (1): Step of coating the liquid crystal aligning agent on a substrate>

[0178] For example, by an appropriate coating method such as a roll coating 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 is a substrate with 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-sided substrate, an opaque object such as a silicon wafer can also be used, and in this case, an electrode that reflects light such as aluminum can also be used for the electrode. In addition, in the case of manufacturing a liquid crystal display element in an IPS driving mode or an FFS driving 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.

[0179] As a method of coating the liquid crystal aligning agent on a substrate to form a film, there can be mentioned: screen printing, offset printing, flexographic printing, inkjet method or spraying method, etc. Among them, a coating and film-forming method using the inkjet method can be preferably used.

[0180] As an IPS substrate of a comb-shaped electrode substrate used in the IPS mode, it has: a substrate; a plurality of linear electrodes formed on the substrate and arranged in a comb shape; and a liquid crystal alignment film formed on the substrate so as to cover the linear electrodes.

[0181] It should be noted that as an FFS substrate of a comb-shaped electrode substrate used in the FFS mode, it 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 shape; and a liquid crystal alignment film formed on the insulating film so as to cover the linear electrodes.

[0182] Figure 1 This is a schematic cross-sectional view showing an example of an in-plane switching (IPS) mode lateral electric field liquid crystal display element having a liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention.

[0183] In Figure 1 In the lateral electric field liquid crystal display element 1 exemplified in

[0184] In Figure 1 the lateral electric field liquid crystal display element 1, when a voltage is applied to the linear electrodes 2b, an electric field is generated between the linear electrodes 2b as indicated by the power lines L.

[0185] Figure 2 This is a schematic cross-sectional view showing another example of a fringe field switching (FFS) mode lateral electric field liquid crystal display element having a liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention.

[0186] In Figure 2 In the lateral electric field liquid crystal display element 1 exemplified in

[0187] In Figure 2 the lateral electric field liquid crystal display element 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 indicated by the power lines L.

[0188] <Process (2): Process of baking the coated liquid crystal aligning agent>

[0189] Step (2) is a step of baking the liquid crystal aligning agent coated on a substrate to form a film. After coating the liquid crystal aligning agent on the substrate, 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 carried out. The drying and baking steps after coating the liquid crystal aligning agent of the present invention can be carried out at any temperature and time, and can also be carried out multiple times. As the baking temperature, for example, it can be carried out at 40 to 180°C. From the viewpoint of shortening the process, it can be carried out at 40 to 150°C. As the baking time, there is no particular limitation, and examples include 1 to 10 minutes, preferably 1 to 5 minutes. In the case of thermal imidization of a polyimide precursor represented by polyamic acid or polyamic acid ester, when a high-boiling solvent is applied to the liquid crystal aligning agent, after the above baking step, for example, a baking step can be carried out in a temperature range of 150 to 300°C, preferably 150 to 250°C. As the baking time, there is no particular limitation, and examples include a baking time of 5 to 40 minutes, preferably 5 to 30 minutes.

[0190] If the film-like material after baking 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.

[0191] <Step (3): A step of performing an alignment treatment on the film obtained in Step (2)>

[0192] Step (3) is a step of performing an alignment treatment on the film obtained in Step (2) as needed. That is, in a liquid crystal display element with a horizontal alignment method such as an IPS driving method or an FFS driving method, an alignment treatment can be imparted to the coated film. On the other hand, in a liquid crystal display element with a vertical alignment method such as a VA method or a PSA method, the formed coated film can be used as the liquid crystal alignment film as it is, or an alignment treatment can be performed on the coated film. As a method for aligning the liquid crystal alignment film, a rubbing treatment method and a photo-alignment treatment method can be cited, and the photo-alignment treatment method is more preferred. As the photo-alignment treatment method, the following method can be cited: irradiating the surface of the above film-like material with radiation polarized in a certain direction, and performing a heating treatment as appropriate to impart liquid crystal alignment (also referred to as liquid crystal alignment energy). 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.

[0193] The irradiation amount of the above radiation is preferably 1 to 10000 mJ / cm 2 and more preferably 100 to 5000 mJ / cm 2 and further preferably 100 to 1500 mJ / cm 2, particularly preferably 100 to 1000 mJ / cm 2 , more preferably 100 to 400 mJ / cm 2 .

[0194] As the light source of the irradiation light, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deep ultraviolet (Deep UV) lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, a mercury-xenon lamp, an excimer laser (e.g., a KrF excimer laser), a fluorescent lamp, an LED lamp, a halogen lamp (e.g., a sodium lamp), a microwave-excited electrodeless lamp, etc. can be used.

[0195] In addition, when light in a polarized state is used as the irradiation light, the higher the extinction ratio of the polarized light, the higher the anisotropy that can be imparted. For example, in the case of ultraviolet light, the extinction ratio of polarized ultraviolet light is more preferably 10:1 or more, and further preferably 20:1 or more.

[0196] In addition, when irradiating radiation, in order to improve the liquid crystal alignment property, the substrate having the film-like material 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.

[0197] Moreover, in the above method, the liquid crystal alignment film irradiated with polarized radiation can be subjected to a contact treatment with water or a solvent, or the liquid crystal alignment film irradiated with radiation can be subjected to a heat treatment.

[0198] As the solvent for the above contact treatment, as long as it is a solvent that dissolves the decomposition products generated from the film-like material by the irradiation of radiation, there is no particular limitation. Specific examples include: water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate, etc. Among 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.

[0199] The film coated with radiation or the film subjected to the contact treatment can also be subjected to a heat treatment. The temperature of the heat treatment is preferably 50 to 300 °C, more preferably 120 to 250 °C. As the heat treatment time, it is preferably set to 1 to 30 minutes respectively.

[0200] <Liquid Crystal Display Element>

[0201] The liquid crystal display element of the present invention includes the liquid crystal alignment film of the present invention.

[0202] The liquid crystal display element of the present invention can be manufactured, for example, by a method including the following step (4).

[0203] The liquid crystal display element of the present invention can preferably be manufactured by a method including the above steps (1) to (3) and the following step (4).

[0204] <Step (4): Step of manufacturing a liquid crystal cell>

[0205] As described above, two substrates each having a liquid crystal alignment film formed thereon are prepared, and a liquid crystal is disposed between the two substrates disposed opposite to each other. Specifically, the following two methods can be cited.

[0206] In the first method, first, two substrates are disposed opposite to each other with a gap (cell gap) therebetween such that their respective liquid crystal alignment films face each other. Next, the peripheral portions of the two substrates are bonded to each other using a sealant, and a liquid crystal composition is filled into the cell gap defined by the substrate surfaces and the sealant through an injection hole. After contacting the film surface, the injection hole is sealed.

[0207] The second method is a method called the ODF (One Drop Fill) method. For example, an ultraviolet curable sealant is applied to a predetermined portion on one of the two substrates having a liquid crystal alignment film formed thereon, and a liquid crystal composition is further dropped at several predetermined locations on the liquid crystal alignment film surface. Then, the other substrate is bonded in such a manner that 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. Next, ultraviolet light is irradiated onto the entire surface of the substrate to cure the sealant.

[0208] In any of the cases where the above methods are used, it is desirable to further heat to a 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.

[0209] It should be noted that in the case where the coating film has been subjected to a rubbing treatment, the two substrates are disposed opposite to each other such that the rubbing directions of the respective coating films form a predetermined angle, for example, an orthogonal or antiparallel angle.

[0210] As the sealant, for example, an epoxy resin containing a curing agent and alumina balls as spacers can be used.

[0211] The above liquid crystal composition is not particularly limited, and is a composition containing at least one liquid crystal compound (liquid crystal molecule), and various liquid crystal compositions having a positive or negative dielectric anisotropy can be used. It should be noted that hereinafter, a liquid crystal composition having a positive dielectric anisotropy will also be referred to as a positive-type liquid crystal, and a liquid crystal composition having a negative dielectric anisotropy will also be referred to as a negative-type liquid crystal.

[0212] Examples of the liquid crystal composition include a nematic liquid crystal composition, a smectic liquid crystal composition, and a cholesteric liquid crystal composition, among which a nematic liquid crystal composition is preferred.

[0213] 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 (such as a trifluoromethyl group), 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 contain a compound having two or more rigid sites (mesogenic skeletons) exhibiting liquid crystallinity in the molecule (for example, a bis-mesogenic compound in which two rigid biphenyl structures or terphenyl structures are linked by an alkyl group).

[0214] From the viewpoint of improving the liquid crystal alignment property, an additive may be further added to the above liquid crystal composition. Examples of such an additive include a compound having a polymerizable group ((meth)acryloyl group, etc.) (hereinafter, also referred to as a polymerizable compound); an optically active compound (e.g., S-811 manufactured by Merck & Co., Inc.); an antioxidant; an ultraviolet absorber; a pigment; an antifoaming agent; a polymerization initiator; or a polymerization inhibitor, etc.

[0215] Examples of the positive liquid crystal include ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, or MLC-7081 manufactured by Merck & Co., Inc.; PA-1492 manufactured by DIC Corporation, etc.

[0216] Examples of the negative liquid crystal include MLC-6608, MLC-6609, MLC-6610, MLC-6882, MLC-6886, MLC-7026, MLC-7026-000, MLC-7026-100, or MLC-7029 manufactured by Merck & Co., Inc., etc.

[0217] In addition, examples of the liquid crystal containing a compound having a polymerizable group include MLC-3023 manufactured by Merck & Co., Inc.

[0218] 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, which has a liquid crystal layer between a pair of substrates having electrodes: 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.

[0219] In addition, the liquid crystal aligning agent of the present invention is also preferably used in a liquid crystal display element (SC-PVA type liquid crystal display element) manufactured through the following steps and having a liquid crystal layer between a pair of substrates provided with electrodes: 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.

[0220] <Process (4-1): For the case of a PSA type liquid crystal display element>

[0221] Inject or drop a liquid crystal composition containing a polymerizable compound, and otherwise, carry out the same as in the above (4). Examples of the polymerizable compound include compounds having one or more polymerizable groups such as acrylate groups and methacrylate groups in the molecule.

[0222] <Process (4-2): For the case of an SC-PVA type liquid crystal display element>

[0223] It is also possible to adopt a method of manufacturing a liquid crystal display element by carrying out the same as in the above (4) and then through a process of irradiating ultraviolet rays described later. According to this method, similar to the case of manufacturing the above PSA type liquid crystal display element, a liquid crystal display element excellent in response speed under a small light irradiation amount can be obtained.

[0224] The polymerizable compound may be a compound having one or more of the above polymerizable groups in the molecule, and its content is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, based on 100 parts by mass of all the polymer components contained in the liquid crystal aligning agent.

[0225] In addition, the above polymerizable group may also be present in the polymer used for the liquid crystal aligning agent. Examples of such a polymer include a polymer obtained by using a diamine component containing a diamine having the above photopolymerizable group at the terminal for the reaction.

[0226] <Process (4-3): Process of irradiating ultraviolet rays>

[0227] While applying a voltage between the conductive films of the pair of substrates obtained in the above (4-1) or (4-2), the liquid crystal cell is irradiated with light. The voltage applied here can be, for example, a direct current or an alternating current of 5 to 50 V. In addition, as the light for irradiation, for example, ultraviolet rays and visible light including light having a wavelength of 150 to 800 nm can be used, and ultraviolet rays containing light having a wavelength of 300 to 400 nm are preferred. As the light source for irradiation, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, etc. can be used. The light irradiation amount is preferably 1000 to 200000 J / m 2 and more preferably 1000 to 100000 J / m2 .

[0228] Furthermore, a liquid crystal display element can be obtained by attaching a polarizing plate to the outer surface of the liquid crystal cell as needed. Examples of polarizing plates attached to the outer surface of the liquid crystal cell include those formed by sandwiching a polarizing film called an "H film" between cellulose acetate protective films, or those composed solely of the H film, which is formed by absorbing iodine while stretching and aligning polyvinyl alcohol.

[0229] [Example]

[0230] The present invention will be described in further detail below with reference to Examples, but the present invention is not limited to these Examples. The abbreviations of the following compounds and the methods for measuring the various properties are as follows.

[0231] (Tetracarboxylic dianhydride)

[0232] CA-1 to CA-4: compounds represented by the following formulae (CA-1) to (CA-4), respectively.

[0233]

[0234] (Diamine)

[0235] DA-W1 to DA-W2, DA-1 to DA-7: compounds represented by the following formulae (DA-W1) to (DA-W2), (DA-1) to (DA-7), respectively.

[0236]

[0237] (additive)

[0238] AD-1 to AD-2: compounds represented by the following formulae (AD-1) to (AD-2), respectively.

[0239]

[0240] (Solvent)

[0241] NMP: N-methyl-2-pyrrolidone.

[0242] BCS: Ethylene glycol monobutyl ether.

[0243] <Viscosity measurement>

[0244] The measurement was performed at a temperature of 25° C. using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample amount of 1.1 mL and a conical rotor TE-1 (1°34′, R24).

[0245] [Synthesis of polymer]

[0246] <Example 1-1>

[0247] In a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, DA-W1 (2.97 g, 27.4 mmol), DA-W2 (0.742 g, 6.86 mmol), and NMP (56.1 g) were added, and while nitrogen was being fed, the mixture was stirred at room temperature (23 °C, the same hereinafter) until dissolved. Then, CA-1 (6.50 g, 33.2 mmol) and NMP (18.8 g) were added, and the mixture was stirred at room temperature for 1 hour, thereby obtaining a solution of polyamic acid (PAA-A1) (viscosity: 327 mPa·s).

[0248] <Example 1-2>

[0249] In a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, DA-W1 (1.97 g, 18.2 mmol), DA-W2 (0.655 g, 6.06 mmol), DA-1 (1.81 g, 6.06 mmol), and NMP (67.0 g) were added, and while nitrogen was being fed, the mixture was stirred at room temperature until dissolved. Then, CA-1 (5.80 g, 29.6 mmol) and NMP (8.00 g) were added, and the mixture was stirred at room temperature for 1 hour, thereby obtaining a solution of polyamic acid (PAA-A2) (viscosity: 323 mPa·s).

[0250] <Example 1-3>

[0251] In a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, DA-W1 (2.83 g, 26.2 mmol), DA-W2 (0.707 g, 6.54 mmol), and NMP (53.5 g) were added, and while nitrogen was being fed, the mixture was stirred at room temperature until dissolved. Then, CA-2 (2.05 g, 8.18 mmol) and NMP (6.59 g) were added, and the mixture was stirred at room temperature for 2 hours. Then, CA-1 (4.64 g, 23.7 mmol) and NMP (14.9 g) were added, and the mixture was stirred at room temperature for 1 hour, thereby obtaining a solution of polyamic acid (PAA-A3) (viscosity: 320 mPa·s).

[0252] <Example 1-4>

[0253] In a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, DA-W1 (1.88 g, 17.4 mmol), DA-W2 (0.627 g, 5.80 mmol), DA-1 (1.73 g, 5.80 mmol), and NMP (64.1 g) were added, and while nitrogen was being fed, the mixture was stirred at room temperature until dissolved. Then, CA-2 (1.81 g, 7.25 mmol) and NMP (1.03 g) were added, and the mixture was stirred at room temperature for 2 hours. Then, CA-1 (4.16 g, 21.2 mmol) and NMP (9.76 g) were added, and the mixture was stirred at room temperature for 1 hour, thereby obtaining a solution of polyamic acid (PAA-A4) (viscosity: 355 mPa·s).

[0254] <Example 1-5>

[0255] In a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, DA-W1 (1.80 g, 16.7 mmol), DA-W2 (0.601 g, 5.56 mmol), DA-1 (1.66 g, 5.56 mmol), and NMP (61.5 g) were added, and while nitrogen was being fed, the mixture was stirred at room temperature until dissolved. Then, CA-2 (3.48 g, 13.9 mmol) and NMP (10.4 g) were added, and the mixture was stirred at room temperature for 2 hours. Then, CA-1 (2.66 g, 13.6 mmol) and NMP (2.97 g) were added, and the mixture was stirred at room temperature for 1 hour, thereby obtaining a solution of polyamic acid (PAA-A5) (viscosity: 325 mPa·s).

[0256] <Example 1-6>

[0257] In a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, DA-W1 (2.97 g, 27.4 mmol), DA-W2 (0.742 g, 6.86 mmol), and NMP (56.1 g) were added, and while nitrogen was being fed, the mixture was stirred at room temperature until dissolved. Then, CA-3 (1.70 g, 8.58 mmol) and NMP (2.10 g) were added, and the mixture was stirred at 50 °C for 2 hours. Then, CA-1 (4.81 g, 24.5 mmol) and NMP (16.7 g) were added, and the mixture was stirred at room temperature for 1 hour, thereby obtaining a solution of polyamic acid (PAA-A6) (viscosity: 310 mPa·s).

[0258] <Comparative Example 1-1>

[0259] In a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, DA-W1 (2.79 g, 25.8 mmol), DA-2 (1.28 g, 6.46 mmol), and NMP (61.7 g) were added, and while introducing nitrogen, the mixture was stirred at room temperature until dissolved. Then, CA-1 (6.13 g, 31.2 mmol) and NMP (13.1 g) were added, and the mixture was stirred at room temperature for 1 hour, thereby obtaining a solution of polyamic acid (PAA-B1) with a solid component concentration of 12% by mass (viscosity: 347 mPa·s).

[0260] <Comparative Example 1-2>

[0261] In a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, DA-W1 (2.88 g, 26.6 mmol), DA-3 (1.01 g, 6.66 mmol), and NMP (58.9 g) were added, and while introducing nitrogen, the mixture was stirred at room temperature until dissolved. Then, CA-1 (6.32 g, 32.2 mmol) and NMP (15.9 g) were added, and the mixture was stirred at room temperature for 1 hour, thereby obtaining a solution of polyamic acid (PAA-B2) with a solid component concentration of 12% by mass (viscosity: 335 mPa·s).

[0262] <Comparative Example 1-3>

[0263] In a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, DA-W1 (2.83 g, 26.2 mmol), DA-W2 (0.707 g, 6.54 mmol), and NMP (53.5 g) were added, and while introducing nitrogen, the mixture was stirred at room temperature until dissolved. Then, CA-2 (6.14 g, 24.5 mmol) and NMP (17.4 g) were added, and the mixture was stirred at room temperature for 2 hours. Then, CA-1 (1.53 g, 7.78 mmol) and NMP (11.2 g) were added, and the mixture was stirred at room temperature for 1 hour, thereby obtaining a solution of polyamic acid (PAA-B3) with a solid component concentration of 12% by mass (viscosity: 311 mPa·s).

[0264] <Preparation Example 1-1>

[0265] In a 50 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, DA-W1 (0.461 g, 4.26 mmol), DA-4 (1.56 g, 6.39 mmol), DA-5 (2.05 g, 6.39 mmol), DA-6 (1.70 g, 4.26 mmol), and NMP (66.3 g) were added, and while nitrogen was being fed, the mixture was stirred at room temperature until dissolved. Then, CA-4 (4.46 g, 19.9 mmol) and NMP (8.68 g) were added, and the mixture was stirred at 40 °C for 20 hours, thereby obtaining a solution of polyamic acid (PAA-U1) with a solid component concentration of 12% by mass (viscosity: 200 mPa·s).

[0266] <Preparation Example 1-2>

[0267] In a 50 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, DA-W1 (0.476 g, 4.40 mmol), DA-4 (1.61 g, 6.60 mmol), DA-7 (1.80 g, 6.60 mmol), DA-6 (1.75 g, 4.40 mmol), and NMP (64.8 g) were added, and while nitrogen was being fed, the mixture was stirred at room temperature until dissolved. Then, CA-4 (4.61 g, 20.5 mmol) and NMP (10.3 g) were added, and the mixture was stirred at 40 °C for 20 hours, thereby obtaining a solution of polyamic acid (PAA-U2) with a solid component concentration of 12% by mass (viscosity: 207 mPa·s).

[0268] The specifications of the polyamic acid 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 content (mole parts) of each tetracarboxylic acid component or each diamine used relative to 100 mole parts of the total amount of the diamine component used in the polymerization.

[0269] [Table 1]

[0270]

[0271] [Preparation of Liquid Crystal Alignment Agent]

[0272] <Example 2-1>

[0273] Using the solution of polyamic acid (PAA-U1) obtained in Preparation Example 1-1 and the solution of polyamic acid (PAA-A1) obtained in Example 1-1, diluting them with NMP and BCS, and stirring at room temperature for 2 hours, a liquid crystal aligning agent (AL-1) was thus obtained. Among them, the solid content ratio of the polymers (PAA-U1:PAA-A1) was 40:60, the mass ratio of the total solid content of the polymers to each solvent (polymer solid content:NMP:BCS) was 5.5:64.5:30, and with respect to 100 parts by mass of the total amount of the polymers, the compounding ratios of AD-1 and AD-2 were 5 parts by mass and 1 part by mass, respectively.

[0274] <Examples 2-2 to 2-6, Comparative Examples 2-1 to 2-3>

[0275] As shown in Table 2, the polyamic acid used was replaced from PAA-A1 with PAA-A2 to PAA-A3, PAA-B1 to PAA-B3, and the rest was carried out in the same manner as in Example 2-1, whereby liquid crystal aligning agents (AL-2) to (AL-6), (AL-C1) to (AL-C3) were obtained.

[0276] <Example 2-7>

[0277] Using the solution of polyamic acid (PAA-U2) obtained in Preparation Example 1-2 and the solution of polyamic acid (PAA-A3) obtained in Example 1-3, diluting them with NMP and BCS, and stirring at room temperature for 2 hours, a liquid crystal aligning agent (AL-7) was thus obtained. Among them, the solid content ratio of the polymers (PAA-U2:PAA-A3) was 40:60, the mass ratio of the total solid content of the polymers to each solvent (polymer solid content:NMP:BCS) was 5.5:64.5:30, and with respect to 100 parts by mass of the total amount of the polymers, the compounding ratios of AD-1 and AD-2 were 5 parts by mass and 1 part by mass, respectively.

[0278] [Table 2]

[0279]

[0280] In Table 2, the values in parentheses of the polyamic acid represent the content (parts by mass) of each polyamic acid with respect to 100 parts by mass of the total amount of the polymers contained in each liquid crystal aligning agent. The values in parentheses of the additives represent the content (parts by mass) of each additive with respect to 100 parts by mass of the total amount of the polymers contained in each liquid crystal aligning agent.

[0281] [Fabrication of FFS-Driven Liquid Crystal Cell]

[0282] A liquid crystal cell having the structure of an FFS-mode liquid crystal display element was fabricated.

[0283] 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 having a pattern in a planar shape and constituting 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 of the second layer is 300 nm, which is a film thickness that functions as an interlayer insulating film. On the SiN film of the second layer, as the third layer, comb-shaped pixel electrodes formed by patterning an ITO film are arranged to form two pixels, namely a first pixel and a 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 of the first layer and the pixel electrodes of the third layer are insulated by the SiN film of the second layer.

[0284] The pixel electrodes of 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 portion 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 portions as a boundary.

[0285] Next, the obtained liquid crystal aligning agent is filtered through a filter with a pore diameter 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 with columnar spacers having a height of 4 μm and an ITO film formed on the back surface (hereinafter referred to as the counter substrate) by spin coating. After drying on a hot plate at 80°C for 2 minutes, firing is performed in a hot air circulation oven at 230°C for 20 minutes to form a coating film with a film thickness of 100 nm. On the surface of this coating film, at 300 mJ / cm 2The substrate with the 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 film formed on the counter substrate was aligned 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, and an empty cell was fabricated. 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 an FFS-driven liquid crystal cell. Then, the obtained liquid crystal cell was heated at 120 °C for 1 hour and left overnight at 23 °C for evaluation.

[0286] [Evaluation of Liquid Crystal Alignment Stability]

[0287] This evaluation assesses the afterimage (also known as AC afterimage) caused by the degradation of the alignment performance of the liquid crystal alignment film during long-term AC driving.

[0288] For the FFS-driven liquid crystal cell fabricated above, with a high-brightness backlight (light source: LED, brightness: 20000 cd / m 2) Above, an AC voltage of ±10V is applied at a frequency of 60Hz 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 direction in the first region of the pixel and the liquid crystal alignment direction in 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 in the first region of the first pixel. Then, the rotation angle required to minimize the transmitted light intensity in 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 0.15° 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 0.15° is set as "bad". The results are shown in Table 3.

[0289] [Evaluation of flicker generated during driving]

[0290] The liquid crystal cell fabricated above is placed between two polarizing plates arranged with their polarization axes orthogonal, and the LED backlight is lit in advance in the state without voltage application, and the configuration angle of the liquid crystal cell is adjusted to minimize the brightness of the transmitted light. Then, while applying an AC voltage of 30Hz to this liquid crystal cell, the V-T curve (voltage-transmittance curve) is measured, and the AC voltage at which the relative transmittance becomes 23% is calculated as the driving voltage.

[0291] In the measurement of flicker, the pre-lit LED backlight is temporarily turned off, shielded for 72 hours, and then the LED backlight is lit again. At the same time as the backlight starts to be lit, an AC voltage of 30Hz at which the relative transmittance becomes 23% is applied to drive the liquid crystal cell for 60 minutes, and the flicker amplitude is tracked. Regarding the flicker amplitude, the transmitted light of the LED backlight passing through the two polarizing plates and the liquid crystal cell therebetween is read using a data collection / data recorder switch unit 34970A (manufactured by Agilent technologies) connected via a photodiode and an I-V conversion amplifier. The value calculated using the following mathematical formula based on this data is used as the flicker level.

[0292] Flicker level (%) = {Flicker amplitude / (2 × z)} × 100

[0293] In the above formula, z is the value of the luminance when driven by an AC voltage with a frequency of 30 Hz and a relative transmittance of 23%, which is read out using the data collection / data logger switch unit 34970A.

[0294] Regarding the evaluation of flicker, starting from the time point when the LED backlight is turned on and the AC voltage is applied, for 60 minutes, the difference between 3 minutes after the start of measurement and 60 minutes later is calculated as the flicker Δ. It can be said that the smaller the value of this flicker Δ, the better. As an evaluation criterion, when the value of the flicker Δ of the liquid crystal cell obtained above is 0.3% or less, it is defined as "good", and when the value of the flicker Δ is greater than 0.3%, it is defined as "bad", and the evaluation was carried out.

[0295] The evaluation of the flicker level according to the above method is carried out under the temperature condition that the temperature of the liquid crystal cell is 23°C. The results are shown in Table 3.

[0296] [Table 3]

[0297]

[0298] As shown in Table 3, the liquid crystal alignment film obtained from the liquid crystal aligning agent using a diamine component containing DA-W1 and DA-W2 and a tetracarboxylic acid component containing 40 mol% or more of CA-1 exhibits higher liquid crystal alignment stability and higher flicker stability compared to the liquid crystal alignment film obtained from a liquid crystal aligning agent that does not meet the above conditions.

[0299] Industrial applicability

[0300] By using the liquid crystal aligning agent of the present invention, a liquid crystal alignment film can be obtained that suppresses AC afterimages at a higher level than before and reduces charge accumulation and flicker caused by the backlight. Therefore, it can be expected to be used in liquid crystal display elements that require a high display quality level, especially in liquid crystal display elements using the IPS driving method and the FFS driving method. And these elements are also useful in liquid crystal displays for display purposes, dimming windows for controlling light transmission and blocking, optical shutters, etc.

[0301] Explanation of reference numerals:

[0302] 1: Transverse electric field liquid crystal display element, 2: Comb electrode substrate, 2a: Substrate, 2b: Linear electrode, 2c: Liquid crystal alignment film, 2d: Substrate, 2e: Surface electrode, 2f: Insulating film, 2g: Linear electrode, 2h: Liquid crystal alignment film, 3: Liquid crystal, 4: Opposite substrate, 4a: Liquid crystal alignment film, 4b: Substrate, L: Power line.

[0303] It should be noted that the entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2022-209708 filed on December 27, 2022 are incorporated herein by reference as the disclosure of the specification of the present invention.

Claims

1. A liquid crystal aligning agent, characterized in that, Polymer A and Polymer B containing the following, Polymer A: A polymer selected from the group consisting of a polyimide precursor having a repeating unit a1 represented by the following formula (A1) and a polyimide which is an imidized product of the polyimide precursor, Polymer B: A polymer selected from the group consisting of a polyimide precursor having a repeating unit b1 represented by the following formula (B1) and a repeating unit b2 represented by the following formula (B2), and a polyimide which is an imidized product of the polyimide precursor, wherein the proportion of the tetravalent organic group represented by the following formula (X-10) is 40 mol% or more relative to 1 mol of the total of the tetracarboxylic acid residues contained in Polymer B, X1 represents a tetravalent organic group represented by the following formula (X-1), Y1 represents a divalent organic group, R and Z each independently represent a hydrogen atom or a monovalent organic group, and a plurality of R and Z each independently have the above definitions, R1 to R4 each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group, and at least one of R1 to R4 represents a group other than a hydrogen atom in the above definition, * represents a bonding bond, X 1’ represents a tetravalent organic group represented by the following formula (X-10), R' and Z' each independently represent a hydrogen atom or a monovalent organic group, and a plurality of R' and Z' each independently have the above definitions X 2’ represents a tetravalent organic group represented by the following formula (X-10), R' and Z' each independently represent a hydrogen atom or a monovalent organic group, and a plurality of R' and Z' each independently have the above definitions * represents a bonding bond.

2. The liquid crystal aligning agent according to claim 1, wherein, X1 in the formula (A1) is a tetravalent organic group selected from the group consisting of the following formulas (x1-1) to (x1-5), 3. The liquid crystal aligning agent according to claim 1, wherein, Said Y1 has a divalent organic group derived from a diamine, and the diamine is: phenylenediamine and its derivatives, biphenylenediamine and its derivatives, the diamine represented by the following formula (d AL ), a diamine having a tetracarboxylic diimide structure, a diamine having a photo-orienting group, a diamine having a urea bond, a diamine having an amide bond, a diamine having a structure containing at least one nitrogen atom selected from the group consisting of a nitrogen-containing heterocycle, a secondary amino group, and a tertiary amino group, a semi-aromatic diamine having a primary amino group and a secondary amino group, a semi-aromatic diamine having two primary amino groups, or a diamine having a group "-N(D)-". wherein D in the group "-N(D)-" represents a protecting group that is removed by heating and replaced with a hydrogen atom, The nitrogen-containing structure in the diamine having a nitrogen-containing structure is a group other than the two amino groups participating in the polycondensation reaction, 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.

4. The liquid crystal aligning agent according to claim 1, wherein, Polymer A contains 5 to 100 mol% of the total repeating units of Polymer A of the total of the repeating unit a1 and the imidized structural unit of the repeating unit a1.

5. The liquid crystal aligning agent according to claim 1, wherein, Polymer B is a polymer selected from the group consisting of a polyimide precursor further having a repeating unit b3 represented by the following formula (B3) and a polyimide which is an imidized product of the polyimide precursor, In the formula (B3), R' has the same meaning as R' in the above formula (B1), and Z' has the same meaning as Z' in the above formula (B1), X 3’ represents a tetravalent organic group, and Y 3’ represents a divalent organic group and satisfies any one of the following conditions (1) or (2). (1) In Y 3’ In the case of representing a divalent organic group represented by 1,3-phenylene or 1,4-phenylene, X 3’ represents a tetravalent organic group other than the tetravalent organic group represented by the formula (X-10), (2) In Y 3’ In the case where it represents a divalent organic group other than 1,3-phenylene or 1,4-phenylene, X 3’ represents a tetravalent organic group.

6. The liquid crystal aligning agent according to claim 5, wherein, Said X 3’ is a tetravalent organic group represented by any one of the formula (X-1), the following formulas (X-2) to (X-9), the formula (X-10), or the following formulas (X-11) to (X-15).

7. The liquid crystal aligning agent according to claim 1, wherein, The total proportion of the divalent organic groups represented by 1,3-phenylene in the formula (B2) and 1,4-phenylene in the formula (B1) is 60 mol% or more relative to 1 mol of the total divalent organic groups derived from the diamine contained in Polymer B, Both ends of the above 1,3-phenylene or 1,4-phenylene are bonded to a nitrogen atom.

8. The liquid crystal aligning agent according to claim 1 or 5, wherein, Polymer B is a polymer selected from the group consisting of the following combinations (pb1) to (pb2), It should be noted that in the following embodiments, the terminals of the polymer are optionally capped. (pb1): A polymer selected from the group consisting of a polyimide precursor containing repeating units b1 and b2 and a polyimide which is an imidized product of the polyimide precursor. (pb2): A polymer selected from the group consisting of a polyimide precursor containing repeating units b1, b2, and b3 and a polyimide which is an imidized product of the polyimide precursor.

9. The liquid crystal aligning agent according to any one of claims 1 to 7, wherein the liquid crystal aligning agent is used for a liquid crystal alignment film for a photo-alignment treatment method.

10. A liquid crystal alignment film obtained from the liquid crystal aligning agent according to any one of claims 1 to 7.

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

12. A method for manufacturing a liquid crystal alignment film, comprising the following steps (1) to (3): Step (1): A step of coating the liquid crystal aligning agent according to any one of claims 1 to 7 on a substrate; Step (2): A step of firing the coated liquid crystal aligning agent to form a film; and Step (3): A step of performing an alignment treatment on the film obtained in step (2) as needed.

13. The method for manufacturing a liquid crystal alignment film according to claim 12, wherein the alignment treatment is a photo-alignment treatment.

14. The method for manufacturing a liquid crystal alignment film according to claim 13, wherein the liquid crystal alignment film is used for a liquid crystal display element using an IPS driving method or an FFS driving method.

15. A method for manufacturing a liquid crystal display element, wherein a liquid crystal alignment film obtained by the manufacturing method according to claim 12 is formed on two substrates, and liquid crystal is disposed between the two substrates arranged in a facing manner with the liquid crystal alignment films.

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