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

Abstract

A liquid crystal alignment agent suitable for a photoalignment method is provided, which can obtain a liquid crystal display element with improved contrast, having high liquid crystal alignment and suppressing deviation in brightness within a plane during black display. The liquid crystal alignment agent comprises a polymer (A) which is an imidized polymer of a polyimide precursor containing a repeating unit of the following formula (0) and a repeating unit of the following formula (1), wherein the imidization rate of the imidized polymer is 80 to 95%. (In the formulas, X represents a tetravalent organic group represented by the following formula (g), Y represents a divalent organic group derived from an aromatic diamine satisfying conditions (1) and (2), Y1 represents a divalent organic group derived from an aromatic diamine (d1) satisfying conditions (1) and (3) below, and R and Z each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. In formulas (0) and (1), X may be the same or different.)

Description

Technology Field

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

[0002] Liquid crystal display devices have been widely used as display units for personal computers, smartphones, mobile phones, television receivers, etc. A liquid crystal display device comprises, for example, a liquid crystal layer placed between a device substrate and a color filter substrate, a pixel electrode and a common electrode that apply an electric field to the liquid crystal layer, an alignment layer that controls the orientation of liquid crystal molecules in the liquid crystal layer, and a thin-film transistor (TFT) that switches an electrical signal supplied to the pixel electrode. As for the driving method of liquid crystal molecules, forward electric field methods such as TN and VA methods, and transverse electric field methods such as IPS and FFS (Fringe Field Switching) methods are known.

[0003] Currently, the most widely used liquid crystal alignment film in industry is manufactured by performing a so-called rubbing treatment, which involves rubbing the surface of a film formed on an electrode substrate—composed of polyamic acid and / or polyimide formed by imidizing it—in a unidirectional manner with a cloth such as cotton, nylon, or polyester. Rubbing is an industrially useful method that is simple and offers excellent productivity. However, with the increase in performance, miniaturization, and size of liquid crystal display devices, various problems arising from rubbing treatment are becoming apparent, such as surface scratches, oscillations, effects caused by mechanical forces or static electricity, and non-uniformity within the alignment surface. As an alignment treatment method to replace rubbing, photoalignment is known, which imparts liquid crystal alignment capability by irradiating with polarized radiation. Photoalignment methods utilizing photoisomerization reactions, photocrosslinking reactions, and photodecomposition reactions have been proposed (see Non-patent Literature 1 and Patent Literature 1).

[0004] A liquid crystal alignment layer, which is a component of a liquid crystal display element, is a film for uniformly arranging liquid crystals, and liquid crystal alignment is one of the important characteristics. However, liquid crystal alignment layers obtained by the above photo-alignment method tend to have lower liquid crystal alignment compared to liquid crystal alignment layers obtained by conventional rubbing treatment, and thus the range of application for liquid crystal display devices equipped with such liquid crystal alignment layers has been limited. Prior art literature

[0005] Japanese Patent Publication No. Hei 9-297313, International Publication No. 2015 / 050135, Pamphlet

[0006] "Liquid Crystal Optical Alignment Layer" Waki ​​Kido, Ichimura Functional Materials, November 1997 Issue Vol.17, No.11, pp. 13–22 The problem to be solved

[0007] Furthermore, in actual liquid crystal display devices, the twist angle within the display surface becomes slightly distorted due to manufacturing variations and other factors. Consequently, caused by such in-plane deviations, the brightness of the liquid crystal display device during black display becomes distorted within the surface.

[0008] The present invention has been made in consideration of the above circumstances, and has one objective of providing a liquid crystal alignment agent suitable for photo-alignment methods, which can obtain a liquid crystal display element with improved contrast that has high liquid crystal alignment and suppresses brightness variation within a plane during black display. means of solving the problem

[0009] As a result of conducting the aforementioned research, the inventors discovered that the above problem could be solved by using a liquid crystal alignment agent containing a specific component, and thus completed the present invention. Specifically, the gist of the invention is as follows.

[0010] In addition, throughout this specification, halogen atoms may include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc., and * indicates a bond loss.

[0011] A liquid crystal orientation agent characterized by containing a polymer (A) in which the imidization rate of the imidization polymer is 80 to 95%, as an imidized polymer of a polyimide precursor containing a repeating unit (a0) represented by the following formula (0) and a repeating unit (a1) represented by the following formula (1).

[0012] [Chemical Formula 1]

[0013]

[0014] (In formulas (0) and (1), X represents a tetravalent organic group represented by the following formula (g), Y represents a divalent organic group derived from an aromatic diamine (d0) satisfying the following conditions (1) and (2), Y1 represents a divalent organic group derived from an aromatic diamine (d1) satisfying the following conditions (1) and (3), R and Z each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and X may be the same or different.)

[0015] [Chemical Formula 2]

[0016]

[0017] (In formula (g), 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 among the definitions above, and also, a portion of the -CH2- included in the alkyl group, alkenyl group, alkynyl group and the monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom may be substituted with -O-.)

[0018] Condition (1): It does not have a side chain with 6 or more carbon atoms.

[0019] Condition (2): The two carbon-nitrogen bond axes originating from the amino group are not parallel to each other.

[0020] Condition (3): Two carbon-nitrogen bond axes originating from the amino group are parallel to each other and have a substructure represented by the following formula (O).

[0021] [Chemical Formula 3]

[0022]

[0023] (In formula (O), Ar independently represents a benzene ring, a biphenyl structure, or a naphthalene ring, any hydrogen atom on the ring may be substituted with a halogen atom or a monovalent organic group, and Q2 is -(CH2) n - (n is an integer from 2 to 18), or the above -(CH2) n - represents a group formed by substituting any -CH2- with -O-, -C(=O)-, or -OC(=O)-, and * represents an associative hand.). Effects of the invention

[0024] According to the present invention, a liquid crystal display element with high liquid crystal alignment and excellent contrast with suppressed brightness variation within a plane during black display, and a liquid crystal alignment agent suitable for a photo-alignment method capable of obtaining the same are provided. Specific details for implementing the invention

[0025] <Polymer (A)>

[0026] The liquid crystal alignment agent of the present invention is an imidized polymer of a polyimide precursor containing a repeating unit (a0) represented by the formula (0) and a repeating unit (a1) represented by the formula (1), and contains a polymer (A) in which the imidization rate of the imidized polymer is 80 to 95%.

[0027] [Chemical Formula 4]

[0028]

[0029] (In formulas (0) and (1), X represents a tetravalent organic group represented by the following formula (g), Y represents a divalent organic group derived from an aromatic diamine (d0) satisfying the following conditions (1) and (2), Y1 represents a divalent organic group derived from an aromatic diamine (d1) satisfying the following conditions (1) and (3), R and Z each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and X may be the same or different.)

[0030] [Chemical Formula 5]

[0031]

[0032] (In formula (g), 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 definitions, and also, a portion of the -CH2- included in the alkyl group, alkenyl group, alkynyl group and the monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom may be substituted with -O-, and * indicates a bond loss.)

[0033] Condition (1): It does not have a side chain with 6 or more carbon atoms.

[0034] Condition (2): The two carbon-nitrogen bond axes originating from the amino group are not parallel to each other.

[0035] Condition (3): Two carbon-nitrogen bond axes originating from the amino group are parallel to each other and have a substructure represented by the following formula (O).

[0036] [Chemical Formula 6]

[0037]

[0038] (In formula (O), Ar independently represents a benzene ring, a biphenyl structure, or a naphthalene ring, any hydrogen atom on the ring may be substituted with a halogen atom or a monovalent organic group, and Q2 is -(CH2) n - (n is an integer from 2 to 18), or the above -(CH2) n - represents a group formed by substituting any -CH2- with -O-, -C(=O)-, or -OC(=O)-, and * represents an associative hand.)

[0039] By configuring it in this way, a liquid crystal display element with high liquid crystal alignment and excellent contrast can be obtained.

[0040] Here, the phrase “two carbon-nitrogen bond axes originating from the amino group are parallel to each other” in the above condition (3) means that when the aromatic diamine is represented as a spherical or rod-shaped molecular structure model (e.g., the HGS molecular structure model manufactured by Maruzen Publishing), the two carbon-nitrogen bond axes originating from the amino group can be arranged to be parallel to each other. Also, the phrase “two carbon-nitrogen bond axes originating from the amino group are not parallel to each other” in the above condition (2) means that when the aromatic diamine is represented as a spherical or rod-shaped molecular structure model, the two carbon-nitrogen bond axes originating from the amino group cannot be arranged to be parallel to each other.

[0041] In addition to the above method, for example, by using molecular modeling (Chem3D Ultra Version 16.0.1.4) to optimize the molecular structure and minimize energy with default MM2 force field settings, and converging to a minimum (root mean square) RMS gradient of 0.010, the case where two carbon-nitrogen bond axes originating from the amino group are arranged to be parallel to each other is defined as "two carbon-nitrogen bond axes originating from the amino group are parallel to each other" in the above condition (3), and the case where two carbon-nitrogen bond axes originating from the amino group are not arranged to be parallel to each other is defined as "two carbon-nitrogen bond axes originating from the amino group are not parallel to each other" in the above condition (2).

[0042] Specific examples of the alkyl group having 1 to 6 carbon atoms in R1 to R4 of the above formula (g) include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, etc. Specific examples of the alkenyl group having 2 to 6 carbon atoms in R1 to R4 include, for example, a vinyl group, a propenyl group, a butynyl group, etc., and these may be in a straight chain form or a branched form. Specific examples of the alkynyl group having 2 to 6 carbon atoms in R1 to R4 include, for example, an ethynyl group, a 1-propynyl group, a 2-propynyl group, etc. The halogen atoms in R1 to R4 include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. Examples of monovalent organic groups having 1 to 6 carbon atoms containing fluorine atoms include fluoromethyl groups, trifluoromethyl groups, etc. In addition, some of the -CH2- included in the above alkyl groups, alkenyl groups, alkynyl groups, and monovalent organic groups having 1 to 6 carbon atoms containing fluorine atoms may be substituted with -O-.

[0043] In addition, for the purpose of efficiently obtaining the effects of the present invention, at least one of R1 to R4 represents a group other than a hydrogen atom in the above definition. By making the above configuration, the photoreactivity of the polyimide film is increased, and the in-plane anisotropy of the resulting liquid crystal alignment film is increased, so the decrease in contrast caused by the deviation of the twist angle within the liquid crystal display element surface that occurs during manufacturing is suppressed.

[0044] From the perspective of high photoreactivity, the tetravalent organic group represented by the above formula (g) is preferably a tetravalent organic group represented by any one of the following formulas (g-1) to (g-5), and more preferably a tetravalent organic group represented by the following formula (g-1). * indicates a bond loss.

[0045] [Chemical Formula 7]

[0046]

[0047] Any hydrogen atom on the ring of Ar in the above formula (O) may be substituted with a monovalent organic group, such as 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, or a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom. Specific examples of these monovalent organic groups include the structures exemplified in R1 to R4 above.

[0048] (aromatic diamine (d0))

[0049] The above aromatic diamine (d0) is preferably an aromatic diamine having 4 to 40 carbon atoms, in particular, from the view that the effects of the present invention are efficiently obtained. Specific examples include an aromatic diamine containing one aromatic ring within the molecule; an aromatic diamine containing two aromatic rings within the molecule, wherein the two aromatic rings are connected to a divalent organic group in which -CH2-, -C(CH3)2-, -O-, -C(=O)-, -OC(=O)-, -NR-C(=O)-, -NR- (where R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a phenyl group, a tert-butoxycarbonyl group), an alkylene group having 2 to 20 carbon atoms, or a portion of the -CH2- of the alkylene group is substituted with -O-, -Si(CH3)2-, -C(=O)-, -OC(=O)-, -NR-C(=O)-, -NR-, and the total number of carbon atoms, oxygen atoms, silicon atoms, and nitrogen atoms in the main chain direction of the linker is odd; and an aromatic diamine having one aromatic ring within the molecule and Examples include aromatic diamines having a monocyclic structure, aromatic diamines having three or more aromatic rings within the molecule, and aromatic diamines having a heterocyclic structure. Examples of the aromatic rings include, for instance, a benzene ring, a naphthalene ring, and an anthracene ring; benzene rings and naphthalene rings are preferred, and benzene rings are more preferred. Additionally, some of the hydrogen atoms on the aromatic ring may be substituted with a hydroxyl group, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a carboxyl group, a halogen atom, a monovalent organic group having 1 to 5 carbon atoms containing a fluorine atom, a group in which some of the hydrogen atoms on the alkyl group having 1 to 5 carbon atoms are substituted with a hydroxyl group, or -NH(Boc) (Boc represents a tert-butoxycarbonyl group).

[0050] More specifically, examples include aromatic diamines represented by the following formulas (d0-1) to (d0-15), 1,3-bis(4-aminophenoxy)benzene, and bis[4-(4-aminophenoxy)phenyl]ether.

[0051] [Chemical Formula 8]

[0052]

[0053] [Chemical Formula 9]

[0054]

[0055] (In the above formula, R represents a hydroxyl group, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a carboxyl group, a halogen atom, a monovalent organic group having 1 to 5 carbon atoms containing a fluorine atom, or a group in which a portion of the hydrogen atoms on the alkyl group having 1 to 5 carbon atoms are substituted with a hydroxyl group, and R' represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Also, if there are multiple R and R', each R and R' may be identical or different from each other. L represents -CH2-, -C(CH3)2-, -O-, -C(=O)-, -OC(=O)-O-, -NR-C(=O)-NR-, -NR- (R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a phenyl group, or a tert-butoxycarbonyl group (represents), represents a divalent organic group having 2 to 20 carbon atoms, or a portion of the -CH2- of the alkylene group substituted with -O-, -Si(CH3)2-, -C(=O)-, -OC(=O)-, -NR-C(=O)-, or -NR-, and the total number of carbon atoms, oxygen atoms, silicon atoms, and nitrogen atoms in the direction of the main chain is odd. L' represents a divalent organic group other than -NR- among the divalent organic groups defined by L above. Q, Q', and Q' represent complex rings. However, each bond formed between Q' and the benzene ring is not parallel to each other, and in Equations (d0-10) and (d0-11), each bond formed between Q' and the nitrogen atom is not parallel to each other. In Equation (d0-9), when n is 0, each bond formed between Q' and the nitrogen atom is When n is 1, the respective bonds formed between Q" and the nitrogen atom are not parallel to each other. Also, in Equation (d0-13), the bonds formed between Q and the adjacent nitrogen atom and carbon atom are not parallel to each other. When there are multiple Qs in the above equation, each Q may be the same or different.Also, n in the above identical expressions may be the same or different.)

[0056] Specific examples of the complex ring in the above Q, Q', and Q' include pyrrole, imidazole, pyrazol, triazole, pyridine, pyrimidine, pyridazine, pyrazine, indole, benzimidazole, purine, quinoline, isoquinoline, naphthiridine, quinoxaline, phthalazine, triazine, carbazole, acridine, piperidine, piperazine, pyrrolidine, hexamethyleneimine, oxazolin, etc. Additionally, any hydrogen atom on the complex ring may be substituted with at least one selected from the group consisting of a C1-3 alkyl group, a C1-3 alkoxy group, a C1-3 fluorine-containing alkyl group, a C1-3 fluorine-containing alkoxy group, and a fluorine atom. A more preferred specific example of the complex ring is These are pyrrole, pyridine, pyrimidine, pyridazine, pyrazine, benzimidazole, carbazole, piperidine, piperazine, and oxazolin. The statement “each bond formed between Q’ and the benzene ring is not parallel to each other” indicates, for example, that, taking pyridine as an example, the bonding position of pyridine bonded to the benzene ring is the 2,4- position, 2,6- position, or 3,5- position, and the statement “each bond formed between Q” and the nitrogen atom is not parallel to each other” indicates, for example, that, taking pyridine as an example, the bonding position of pyridine bonded to the nitrogen atom is the 2,4- position, 2,6- position, or 3,5- position. "Each bond formed between 'Q' and the nitrogen atom is parallel to each other" indicates that, taking pyridine as an example, the bond position of pyridine bonded to the nitrogen atom is the 2,5-position. Also, "each bond formed between Q and the adjacent nitrogen atom and carbon atom is not parallel to each other" indicates that, taking pyridine as an example, the bond position of pyridine bonded to the adjacent nitrogen atom or carbon atom is the 2,4-position, 2,6-position, or 3,5-position.

[0057] As a more preferred specific example of an aromatic diamine (d0), 1,3-diaminobenzene, 2,4-diaminotoluene, 2,6-diaminotoluene, 2,4-diaminophenol, 3,5-diaminophenol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzoic acid, 3,5-diaminobenzoic acid, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, bis(4-aminophenoxy)methane, 1,5-bis(4-aminophenoxy)pentane, 1,3-bis(4-aminophenethyl)urea, 4,4'-diaminodiphenyl ether, 2,2-bis(3-aminophenyl)propane, 2,2-bis(4-aminophenyl)propane, 4,4'-Diaminobenzophenone, 1-(4-aminophenyl)-1,3,3-trimethyl-1H-indane-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine, diamines represented by the following formulas (Dp-1) to (Dp-2), diamines represented by the following formulas (5-1) to (5-4), 1,3-bis(4-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]ether, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, the following formula Examples include aromatic diamines containing a complex ring within the molecule, such as (z-1) ~ (z-17), the following formulas (Ox-1) ~ (Ox-2), or a diamine represented by the following formula (Si-1). Among the following formulas (5-1) ~ (5-4), "Boc" represents a tert-butoxycarbonyl group.

[0058] [Chemical Formula 10]

[0059]

[0060] [Chemical Formula 11]

[0061]

[0062] [Chemical Formula 12]

[0063]

[0064] (In the formula, Py represents, respectively, a 2,5-pyridinylene group or a 2,5-pyrimidinylene group.)

[0065] [Chemical Formula 13]

[0066]

[0067] [Chemical Formula 14]

[0068]

[0069] [Chemical Formula 15]

[0070]

[0071] [Chemical Formula 16]

[0072]

[0073] In the above formula (1), Y is preferably a divalent organic group derived from 1,3-diaminobenzene, 2,4-diaminotoluene, 2,6-diaminotoluene, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, bis(4-aminophenoxy)methane, 1,5-bis(4-aminophenoxy)pentane, 1,3-bis(4-aminophenethyl)urea, 4,4'-diaminodiphenyl ether, 2,2-bis(3-aminophenyl)propane, 2,2-bis(4-aminophenyl)propane, 4,4'-diaminobenzophenone, or 1,3-bis(4-aminophenoxy)benzene, in order to increase liquid crystal orientation.

[0074] (aromatic diamine (d1))

[0075] The above aromatic diamine (d1) is preferably an aromatic diamine having 4 to 40 carbon atoms, in particular, from the perspective of efficiently obtaining the effects of the present invention. In addition, it is preferable that the total number of carbon atoms and oxygen atoms in the main chain direction of Q2 in (d1) is an even number. The preferred total number of carbon atoms and oxygen atoms in the main chain direction is 2n (where n represents an integer from 1 to 9, 1 to 8 is preferred, and 1 to 6 is more preferred). As a specific example of an aromatic diamine, an aromatic diamine in which two amino groups are bonded to the substructure represented by the above formula (O) can be cited.

[0076] In the above formula (1), Y1 is preferably a divalent organic group derived from a diamine represented by the following formulas (d1-1) to (d1-14) in order to increase liquid crystal orientation.

[0077] [Chemical Formula 17]

[0078]

[0079] [Chemical Formula 18]

[0080]

[0081] The polymer (A) may additionally be an imidized polymer of a polyimide precursor having a repeating unit (a2) represented by the following formula (2) which is different from the repeating unit (a0) or (a1).

[0082] [Chemical Formula 19]

[0083]

[0084] In the above formula (2), X2 represents a tetravalent organic group, Y2 represents a divalent organic group derived from an aromatic diamine that does not have a side chain with 6 or more carbon atoms, and R and Z have the same meaning as R and Z of the above formula (0). However, if X2 has the same meaning as the tetravalent organic group represented by the above formula (g), Y2 represents a structure other than the divalent organic group defined as Y in the above formula (0) or the divalent organic group defined as Y1 in the above formula (1). Specific examples of X2 include, in addition to the tetravalent organic group represented by the above formula (g), a tetravalent organic group represented by any one of the following formulas (X-1) to (X-25), a tetravalent organic group derived from an aromatic tetracarboxylic acid dihydride, etc.

[0085] [Chemical Formula 20]

[0086]

[0087] [Chemical Formula 21]

[0088]

[0089] Here, aromatic tetracarboxylic acid dihydride refers to an acid dihydride obtained by intramolecular dehydration of a carboxyl group bonded to an aromatic ring, such as a benzene ring or a naphthalene ring. Specific examples include a tetravalent organic group represented by any one of the following formulas (Xa-1) to (Xa-2) and a tetravalent organic group represented by the following formulas (Xr-1) to (Xr-7).

[0090] [Chemical Formula 22]

[0091]

[0092] (In the above formulas (Xa-1) to (Xa-2), x and y are each independently a single bond, ether, carbonyl, ester, an alkanediyl group having 1 to 10 carbon atoms, 1,4-phenylene, sulfonyl, or amide group. j and k are integers of 0 or 1. * indicates a bond hand.)

[0093] [Chemical Formula 23]

[0094]

[0095] The tetravalent organic group represented by the above formula (Xa-1) or (Xa-2) may be a structure represented by any of the following formulas (Xa-3) to (Xa-19).

[0096] [Chemical Formula 24]

[0097]

[0098] [Chemical Formula 25]

[0099]

[0100] In order to efficiently obtain the effects of the present invention, it is preferable that X2 is a tetravalent organic group represented by the above formula (g) or a tetravalent organic group represented by any one of the above formulas (X-1) to (X-25), and it is more preferable that X2 is a tetravalent organic group represented by the above formula (g).

[0101] Specific examples of the divalent organic group of Y2 include, in addition to the divalent organic group defined as Y in Formula (0) or the divalent organic group defined as Y1 in Formula (1), 2 from diamines such as p-phenylenediamine, 4,4'-diamino-2,2'-dimethylbiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, and 4,4'-diaminobenzanilide. A group from which two amino groups have been removed; a divalent organic group represented by the following formula (h-1); a divalent organic group having a photooriented group such as the following formulas (h-2) to (h-4); a divalent organic group represented by (h-5); 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 2,5-diaminobenzoic acid, 4,4'-diaminobiphenyl-3,3'-dicarboxylic acid; a diamine having a diphenylamine backbone such as the following formulas (Dp-5) to (Dp-6); a diamine having "-N(D)- (D represents a carbamate-based protecting group, more preferably a tert-butoxycarbonyl group)" in the molecule such as the following formulas (5-5) to (5-9); a diamine from which two amino groups have been removed, such as the diamine represented by (z-18) to (z-23). Can lift the flag.

[0102] [Chemical Formula 26]

[0103]

[0104] (In the above formula, * represents coupling loss.)

[0105] [Chemical Formula 27]

[0106]

[0107] [Chemical Formula 28]

[0108]

[0109] (In the above formula, Boc represents a tert-butoxycarbonyl group.)

[0110] [Chemical Formula 29]

[0111]

[0112] (In the above formulas, Py independently represents a 2,5-pyridinylene group or a 2,5-pyrimidinylene group.)

[0113] The polymer (A) may additionally be an imidized polymer of a polyimide precursor having a repeating unit (a3) ​​represented by the following formula (3) which is different from the repeating units (a0), (a1), and (a2).

[0114] [Chemical Formula 30]

[0115]

[0116] In the formula, X3 represents a tetravalent organic group, Y3 represents a divalent organic group other than the divalent organic group defined as Y2 in the formula (2), and R and Z have the same meaning as R and Z in the formula (0). However, if X3 has the same meaning as the tetravalent organic group represented by the formula (g), Y3 represents a structure other than the divalent organic group defined as Y in the formula (0) or the divalent organic group defined as Y1 in the formula (1). Specific examples of X3 include the structure exemplified by X2 in the formula (2), and from the perspective of obtaining the effects of the present invention, it is preferably the tetravalent organic group represented by the formula (g).

[0117] Specific examples of the divalent organic group of Y3 include diamines having a photopolymerizable group at the terminal end such as N-phenyl-3,6-diaminocarbazole, 2-(2,4-diaminophenoxy)ethyl methacrylate, and 2,4-diamino-N,N-diallyaniline; diamines having a steroid backbone such as cholestanyloxy-3,5-diaminobenzene, cholestenioxy-3,5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, 3,5-diaminobenzoate cholestanyl, 3,5-diaminobenzoate cholestenyl, 3,5-diaminobenzoate lanostanyl, and 3,6-bis(4-aminobenzoyloxy)cholestan; diamines represented by the following formulas (V-1) to (V-6); diamines represented by the following formulas (z-24) to (z-25); and the following formulas (5-10). Examples include a diamine represented by (5-13), alicyclic diamines such as bis(4-aminocyclohexyl)methane and bis(4-amino-3-methylcyclohexyl)methane, a group obtained by removing two amino groups from a diamine such as 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, and 1,12-diaminododecane, and aliphatic diamines such as 1,10-diaminodecane, 1,11-diaminoundecane, and 1,12-diaminododecane, and a group represented by any of the formulas (Y-1) to (Y-167) described in International Publication No. 2018 / 117239. In order to obtain the effects of the present invention in a desirable manner, Y3 is preferably a group obtained by removing two amino groups from a diamine represented by formulas (5-10) to (5-13).

[0118] [Chemical Formula 31]

[0119]

[0120] (Among the above equations (V-1) ~ (V-6), X v1 ~ X v4 , X p1 ~ X p2 is, each independently, -(CH2) a- (a is an integer from 1 to 15), representing -CONH-, -NHCO-, -CON(CH3)-, -NH-, -O-, -CH2O-, -CH2OCO-, -COO-, or -OCO-, and X v5 represents -O-, -CH2O-, -CH2OCO-, -COO-, or -OCO-, and Xa is a single bond, -O-, -NH-, -O-(CH2) m -O- (m represents an integer from 1 to 6), and R v1 ~ R v4 , R 1a ~ R 1b Each represents, independently, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms.

[0121] [Chemical Formula 32]

[0122]

[0123] [Chemical Formula 33]

[0124]

[0125] (In the above formula, Boc represents a tert-butoxycarbonyl group.)

[0126] In order to obtain the effects of the present invention, the polymer (A) preferably has a sum of repeating units (a0), repeating units (a1), and their imidized repeating units of 5 mol% or more with respect to the total repeating units, and more preferably 10 mol% or more.

[0127] In order to obtain the effects of the present invention, the polymer (A) preferably comprises 1 to 40 mol% of repeating units (a1) and the imidized repeating units with respect to the total repeating units, more preferably 1 to 35 mol%, and even more preferably 1 to 30 mol%.

[0128] In order to obtain the effects of the present invention, the polymer (A) preferably comprises 1 to 95 mol% of repeating units (a2) and the imidized repeating units with respect to the total repeating units, more preferably 1 to 90 mol%, and even more preferably 5 to 90 mol%.

[0129] In order to obtain the effects of the present invention, the polymer (A) preferably comprises 1 to 40 mol% of repeating units (a3) ​​and the imidized repeating units with respect to the total repeating units, more preferably 1 to 30 mol%, and even more preferably 1 to 25 mol%.

[0130] In addition, the imidized repeating unit of the polymer (A) is 95 mol% or less.

[0131] When the polymer (A) comprises repeating units other than repeating units (a0), repeating units (a1), and their imidized repeating units, it is preferable that the sum of the repeating units (a0), repeating units (a1), and their imidized repeating units be 95 mol% or less, and more preferable that it be 90 mol% or less.

[0132] <Polymer (B)>

[0133] In addition to the polymer (A), the liquid crystal alignment agent of the present invention may contain at least one polymer (B) selected from the group consisting of a polyimide precursor and a polyimide with an imidization rate of less than 80%. For efficient use of the effects of the present invention, the polymer (B) may be a polymer having a repeating unit represented by the following formula (4).

[0134] [Chemical Formula 34]

[0135]

[0136] (In the above formula (4), X4 is a tetravalent organic group and Y4 is a divalent organic group. Z represents, respectively, a hydrogen atom, an alkyl group having 1 to 10 carbon atoms that may have a substituent, an alkenyl group having 2 to 10 carbon atoms that may have a substituent, an alkynyl group having 2 to 10 carbon atoms that may have a substituent, a tert-butoxycarbonyl group, or a 9-fluorenylmethoxycarbonyl group, and R represents, respectively, a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.)

[0137] The tetravalent organic group in X4 of the above formula (4) may be a tetravalent organic group derived from an aliphatic tetracarboxylic acid dihydride, a tetravalent organic group derived from an alicyclic tetracarboxylic acid dihydride, or a tetravalent organic group derived from an aromatic tetracarboxylic acid dihydride, and as a specific example, the tetravalent organic group exemplified in X2 above may be used. From the perspective of efficiently obtaining the effects of the present invention, X4 is preferably a tetravalent organic group represented by the above formula (g), a tetravalent organic group represented by any one of the above formulas (X-1) to (X-25), a tetravalent organic group represented by the above formulas (Xa-1) to (Xa-2), or a tetravalent organic group represented by the above formulas (Xr-1) to (Xr-7) (these are collectively referred to as "specific tetravalent organic groups").

[0138] In order to efficiently obtain the effects of the present invention, the polymer (B) preferably contains at least 5 mol% of the total repeating units containing X4, which is the specific tetravalent organic group, and more preferably contains at least 10 mol%.

[0139] As for the divalent organic group in Y4 of the above equation (4), examples include the divalent organic group in the above equation (0) or the divalent organic group exemplified in Y1 to Y3 in the above equations (1) to (3). In the view that there is little residual DC-derived residue, the polymer (B) is preferably a polymer comprising repeating units that are selected from the group consisting of at least one nitrogen-containing structure (hereinafter also referred to as a nitrogen-containing structure) selected from the group consisting of a diamine having a nitrogen-containing heterocyclic ring, a secondary amino group, and a tertiary amino group, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, a divalent organic group from which two amino groups have been removed from a diamine having a carboxyl group, and a divalent organic group from which two amino groups have been removed from a diamine having a urea bond, such as 1,3-bis(4-aminophenethyl)urea (these are collectively referred to as "specific divalent organic groups").

[0140] Examples of the above nitrogen-containing heterocyclic rings include pyrrole, imidazole, pyrazol, triazole, pyridine, pyrimidine, pyridazine, pyrazine, indole, benzimidazole, purine, quinoline, isoquinoline, naphthiridine, quinoxaline, phthalazine, triazine, carbazole, acridine, piperidine, piperazine, pyrrolidine, hexamethyleneimine, etc. Among these, pyridine, pyrimidine, pyrazine, piperidine, piperazine, quinoline, carbazole, or acridine are preferred.

[0141] The secondary amino group and the tertiary amino group that may be present in a diamine having a nitrogen-containing structure are, for example, represented by the following formula (n).

[0142] [Chemical Formula 35]

[0143]

[0144] In the above formula (n), R represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, and "*" represents a bonding loss bonded to the hydrocarbon group.

[0145] Examples of monovalent hydrocarbon groups of R in the above formula (n) include alkyl groups such as methyl, ethyl, and propyl groups; cycloalkyl groups such as cyclohexyl groups; and aryl groups such as phenyl and methylphenyl groups. R is preferably a hydrogen atom or a methyl group.

[0146] Specific examples of diamines having a nitrogen-containing structure include, for example, 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,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine, 4,4'-diaminodiphenylamine, N,N-bis(4-aminophenyl)-methylamine, diamines represented by formulas (Dp-1) to (Dp-6) or diamines represented by formulas (z-1) to (z-25). Can be lifted.

[0147] Specific examples of the diamine having the above-mentioned carboxyl group include 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, or 4,4'-diaminobiphenyl-3,3'-dicarboxylic acid.

[0148] In the view that the polymer (B) has less residual DC-derived residue, Y4 may contain at least 1 mol% of the specific divalent organic repeating unit and at least 5 mol% of the total repeating unit included in the polymer (B).

[0149] In the view that there is less residual DC-derived residue, the content ratio of polymer (A) and polymer (B) may be 10 / 90 to 90 / 10 in mass ratio of [polymer (A)] / [polymer (B)], 20 / 80 to 90 / 10, or 20 / 80 to 80 / 20.

[0150] Method for manufacturing polyamic acid, polyamic acid ester, and polyimide

[0151] The polyimide precursors used in the present invention, namely polyamic acid esters, polyamic acids, and polyimides, which are imidized polymers thereof, can be synthesized by known methods, for example, as described in International Publication WO2013 / 157586.

[0152] The polymer (A) of the present invention is obtained by imidizing the polyimide precursor described above. In the polymer (A), the repeating unit of the polyimide precursor is closed, but the ratio of the repeating unit that is closed to the total repeating unit of the polyimide precursor (also called the closing rate or imidization rate) is 80 to 95%, preferably 82 to 95%, and more preferably 85 to 95%.

[0153] By configuring as above, the liquid crystal alignment film obtained has high liquid crystal alignment properties, so it is possible to obtain the effects of the present invention as described above.

[0154] <Solution Viscosity and Molecular Weight of Polymer>

[0155] The polyamic acid, polyamic acid ester, and polyimide used in the present invention are preferably, from the perspective of workability, to have a solution viscosity of, for example, 10 to 1000 mPa·s when prepared as a solution of 10 to 15 mass%, but are not particularly limited. In addition, the solution viscosity (mPa·s) of the polymer is a value measured at 25°C using an E-type rotary viscometer for a polymer solution of 10 to 15 mass% prepared using a solvent of the polymer (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

[0156] The weight-average molecular weight (Mw) of the above polyamic acid, polyamic acid ester, and polyimide, measured by gel permeation chromatography (GPC), is preferably 1,000 to 500,000 and more preferably 2,000 to 300,000. In addition, the molecular weight distribution (Mw / Mn), expressed as the ratio of Mw to the number-average molecular weight (Mn) of polystyrene measured by GPC, is preferably 15 or less and more preferably 10 or less. By being within this molecular weight range, good orientation and stability of the liquid crystal display device can be secured.

[0157] Liquid crystal alignment agent

[0158] The liquid crystal alignment agent of the present invention contains a polymer (A) and, optionally, a polymer (B). The liquid crystal alignment agent of the present invention may contain other polymers in addition to the polymer (A) and polymer (B). Examples of other polymers include polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene or its derivative, poly(styrene-phenylmaleimide) derivative, poly(meth)acrylate, etc.

[0159] A liquid crystal alignment agent is used to manufacture a liquid crystal alignment film and takes the form of a coating solution in order to form a uniform thin film. In the liquid crystal alignment agent of the present invention, it is preferable that it be a coating solution containing the above-mentioned polymer component and an organic solvent. At that time, the concentration of the polymer in the liquid crystal alignment agent can be appropriately changed according to the setting of the thickness of the coating film to be formed. In terms of forming a uniform and defect-free coating film, 1 mass% or more is preferable, and in terms of the storage stability of the solution, 10 mass% or less is preferable. A particularly preferred polymer concentration is 2 to 8 mass%.

[0160] The organic solvent contained in the liquid crystal alignment agent is not particularly limited as long as the polymer component is uniformly dissolved. Specific examples include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide (collectively referred to as "both solvents"), etc. Among these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, or γ-butyrolactone are preferred. The content of both solvents is preferably 20 to 99 mass% of the total solvent included in the liquid crystal alignment agent, more preferably 20 to 90 mass%, and particularly preferably 30 to 80 mass%.

[0161] In addition, for the organic solvent contained in the liquid crystal alignment agent, it is preferable to use a mixed solvent that combines the above solvent with a solvent (also called a co-solvent) that improves the applicability or surface smoothness of the coating film when applying the liquid crystal alignment agent. Specific examples of the co-solvent used in combination are shown below, but are not limited to these.

[0162] For example, diisopropyl ether, diisobutyl ether, diisobutylcarbinol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol, 2-(2-butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetate, 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, 3-methyl methoxypropionate, 3-ethyl ethoxypropionate, 3-ethyl methoxypropionate, 3-propyl methoxypropionate, 3-butyl methoxypropionate, Examples include n-butyl lactic acid, isoamyl lactic acid, diethylene glycol monoethyl ether, diisobutyl ketone (2,6-dimethyl-4-heptanone), etc.

[0163] Among these, diisobutylcarbinol, 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 is preferred.

[0164] The content of the solvent-free solvent is preferably 1 to 80 mass% of the total solvent included in the liquid crystal alignment agent, more preferably 20 to 80 mass%, and particularly preferably 20 to 70 mass%. The type and content of the solvent-free solvent are appropriately selected according to the coating device, coating conditions, coating environment, etc., of the liquid crystal alignment agent.

[0165] Preferred combinations of solvents of both solvent and poor solvent include N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and diisobutyl ketone, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and diisopropyl ether. Examples include N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether, and diisobutylcarbinol; N-methyl-2-pyrrolidone, γ-butyrolactone, and dipropylene glycol dimethyl ether; N-methyl-2-pyrrolidone, propylene glycol monobutyl ether, and dipropylene glycol dimethyl ether.

[0166] The liquid crystal alignment agent of the present invention may additionally contain components other than polymer components and organic solvents (hereinafter also referred to as additive components). Such additive components may include adhesion aids for increasing the adhesion between the liquid crystal alignment film and the substrate or between the liquid crystal alignment film and the sealant, compounds for promoting imidation, compounds for increasing the strength of the liquid crystal alignment film (hereinafter also referred to as crosslinking compounds), dielectric or conductive materials for adjusting the dielectric constant or electrical resistance of the liquid crystal alignment film.

[0167] As the above-mentioned crosslinking compound, in terms of exhibiting good resistance to AC residue and high improvement in film strength, it may be a compound having at least one group selected from the group consisting of oxiranyl group, oxetanyl group, protected isocyanate group, protected isothiocyanate group, group including oxazoline ring structure, group including meldrum acid structure, cyclocarbonate group, and group represented by the following formula (d), and at least one compound selected from the group consisting of the following formula (e) (hereinafter collectively referred to as compound (C).

[0168] [Chemical Formula 36]

[0169]

[0170] (In formula (d), R2 and R3 are each independently a hydrogen atom, a C1-C3 alkyl group, or "*-CH2-OH", and * represents a bond hand. In formula (e), A represents an organic group of (m + n) having an aromatic ring, R represents a hydrogen atom or a C1-C5 alkyl group, m represents an integer from 1 to 6, and n represents an integer from 0 to 4.)

[0171] In formula (e), the hydrogen atom on the aromatic ring of A may be substituted with a monovalent organic group such as a halogen atom, a carbon-1 to carbon-6 alkyl group, a carbon-2 to carbon-6 alkenyl group, a carbon-2 to carbon-6 alkynyl group, or a carbon-1 to carbon-6 monovalent organic group containing a fluorine atom.

[0172] Specific examples of compounds having oxiranyl groups include compounds having two or more oxiranyl groups, such as the compound described in paragraph

[0037] of Japanese Patent Publication No. Hei 10-338880 or the compound having a triazine ring backbone described in International Patent Publication No. WO2017 / 170483. Among these, the compounds may be compounds containing nitrogen atoms, such as N,N,N',N'-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetraglycidyl-p-phenylenediamine, and compounds represented by the following formulas (r-1) to (r-3).

[0173] [Chemical Formula 37]

[0174]

[0175] Specific examples of compounds having an oxetanyl group include compounds having two or more oxetanyl groups as described in paragraphs

[0170] to

[0175] of International Publication No. 2011 / 132751.

[0176] Specific examples of compounds having a protected isocyanate group include compounds having two or more protected isocyanate groups as described in paragraphs

[0046] to

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

[0119] to

[0120] of International Patent Publication No. 2015 / 141598, and may also be compounds represented by the following formulas (bi-1) to (bi-3).

[0177] [Chemical Formula 38]

[0178]

[0179] Specific examples of compounds having a protected isothiocyanate group include a compound having two or more protected isothiocyanate groups as described in Japanese Patent Publication No. 2016-200798.

[0180] Specific examples of compounds having a group including an oxazoline ring structure include a compound including two or more oxazoline ring structures as described in paragraph

[0115] of Japanese Patent Publication No. 2007-286597.

[0181] Specific examples of compounds having a group including a meldrum acid structure include compounds having two or more meldrum acid structures as described in International Publication WO2012 / 091088.

[0182] Specific examples of compounds having a cyclocarbonate group include the compound described in International Publication WO2011 / 155577.

[0183] Examples of alkyl groups having 1 to 3 carbon atoms in R2 and R3 of the group represented by formula (d) include methyl, ethyl, propyl, and isopropyl groups.

[0184] Specific examples of compounds having a group represented by formula (d) include compounds having two or more groups represented by formula (d) as described in International Patent Publication WO2015 / 072554 or paragraph

[0058] of Japanese Patent Publication No. 2016-118753, compounds described in Japanese Patent Publication No. 2016-200798, etc., and may also be compounds represented by the following formulas (hd-1) to (hd-8).

[0185] [Chemical Formula 39]

[0186]

[0187] Examples of (m + n) valent organic groups having an aromatic ring in A of formula (e) include (m + n) valent aromatic hydrocarbon groups having 6 to 30 carbon atoms, (m + n) valent organic groups formed by directly or through linking groups of aromatic hydrocarbon groups having 6 to 30 carbon atoms, and (m + n) valent groups having an aromatic complex ring. Examples of aromatic hydrocarbon groups include benzene, naphthalene, etc. Examples of aromatic complex rings include pyrrole rings, imidazole rings, pyrazol rings, pyridine rings, pyrimidine rings, quinoline rings, isoquinoline rings, carbazole rings, pyridazine rings, pyrazine rings, benzimidazole rings, indole rings, quinoxaline rings, acridine rings, etc. Examples of linking groups include -NR- (where R is a hydrogen atom or a methyl group), an alkylene group having 1 to 10 carbon atoms, a group from which one hydrogen atom has been removed from an alkylene group, a divalent or trivalent cyclohexane ring, etc. Additionally, any hydrogen atom of the alkylene group may be substituted with an organic group such as a fluorine atom or a trifluoromethyl group. Specific examples of the alkyl groups having 1 to 5 carbon atoms in R of formula (e) may be the alkyl groups exemplified in R1 to R4 of formula (g).

[0188] Specific examples include compounds described in International Publication WO2010 / 074269 and compounds represented by the following formulas (e-1) to (e-10).

[0189] [Chemical Formula 40]

[0190]

[0191] The above compounds are examples of crosslinkable compounds, but are not limited to them. For example, other components disclosed on pages 53

[0105] to 55

[0116] of International Publication No. 2015 / 060357 may be cited. In addition, two or more types of crosslinkable compounds may be combined.

[0192] The content of the crosslinkable compound in the liquid crystal alignment agent of the present invention is preferably 0.5 to 20 parts by mass per 100 parts by mass of the polymer component included in the liquid crystal alignment agent, and more preferably 1 to 15 parts by mass from the view that the crosslinking reaction proceeds and also exhibits good resistance to AC afterimages.

[0193] The above adhesion aids include, for example, 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-ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-Triethoxysilyl-1,4,7-Triazadecane, 9-Trimethoxysilyl-3,6-Diazanonyl Acetate, 9-Triethoxysilyl-3,6-Diazanonyl Acetate, N-Benzyl-3-AminopropylTrimethoxysilane, N-Benzyl-3-AminopropylTrimethoxysilane, N-Phenyl-3-AminopropylTrimethoxysilane, N-Phenyl-3-AminopropylTrimethoxysilane, N-Bis(Oxyethylene)-3-AminopropylTrimethoxysilane, N-Bis(Oxyethylene)-3-AminopropylTrimethoxysilane, VinylTrimethoxysilane, VinylTrimethoxysilane, 2-(3,4-Epoxycyclohexyl)ethylTrimethoxysilane, 3-GlycidoxypropylMethylDimethoxysilane, 3-GlycidoxypropylTrimethoxysilane, Examples of silane coupling agents include 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris-(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatepropyltriethoxysilane. When using a silane coupling agent, from the viewpoint of exhibiting good resistance to AC afterimages, it is preferable that the amount be 0.1 to 30 parts by mass per 100 parts by mass of the polymer component included in the liquid crystal alignment agent, and 0.It is more preferable that it be 1 to 20 parts by mass.

[0194] The compound for promoting imidation is preferably a compound having a basic site (e.g., primary amino group, aliphatic heterocycle (e.g., pyrrolidine backbone), aromatic heterocycle (e.g., imidazole ring, indole ring), or guanidino group, etc.) (except for the crosslinking compound and adhesion aid), or a compound in which the basic site is generated during calcination. More preferably, the compound is one in which the basic site is generated during calcination, and specific examples include compounds represented by the following formulas (B-1) to (B-17). The content of the compound for promoting imidation is preferably 2 moles or less, more preferably 1 mole or less, and even more preferably 0.5 moles or less per 1 mole of the amic acid or amic acid ester portion of the polymer (A).

[0195] [Chemical Formula 41]

[0196]

[0197] (In the above formulas (B-1) to (B-17), D represents an organic group that is detached by heating, preferably either a tert-butoxycarbonyl group or a 9-fluorenylmethoxycarbonyl group, and if there are multiple Ds, each D may be the same or different from one another.)

[0198] Method for manufacturing a liquid crystal alignment layer

[0199] The method for manufacturing a liquid crystal alignment film using the liquid crystal alignment agent of the present invention is characterized by sequentially performing the following steps: applying the liquid crystal alignment agent onto a substrate (step (1)); heating the applied liquid crystal alignment agent to obtain a film (step (2)); irradiating the film obtained in step (2) with polarized ultraviolet light (step (3)); and, if necessary, additionally, firing the film obtained in step (3) at a temperature of 100°C or higher, and also higher than that of step (2) (step (4)).

[0200] <Process (1)>

[0201] The substrate on which the liquid crystal alignment agent used in the present invention is applied is not particularly limited as long as it is a highly transparent substrate, and may use glass substrates, silicon nitride substrates, acrylic substrates, or plastic substrates such as polycarbonate substrates. In that case, using a substrate on which an ITO electrode or the like is formed to drive the liquid crystal is preferable in terms of simplifying the process. Furthermore, in the case of a reflective liquid crystal display device, if only one side of the substrate is used, an opaque material such as a silicon wafer may be used, and in this case, a light-reflecting material such as aluminum may be used for the electrode.

[0202] The method of applying the liquid crystal alignment agent is not particularly limited, but industrially, methods such as screen printing, offset printing, flexographic printing, or inkjet printing are commonly used. Other application methods include the dip method, roll coater method, slit coater method, spinner method, or spray method, and these may be used depending on the purpose.

[0203] <Process (2)>

[0204] Process (2) is a process of forming a film by heating a liquid crystal alignment agent applied on a substrate. Specifically, the liquid crystal alignment agent applied on the substrate in process (1) can be heated by a heating means such as a hot plate, a thermal circulation type oven, or an IR (infrared) type oven to evaporate the solvent or perform thermal imidation of the amic acid or amic acid ester in the polymer. The heating process of the liquid crystal alignment agent applied on the substrate in process (1) can be performed at any temperature and time, and can be performed multiple times. As for the heating temperature, for example, it can be performed at 40 to 180°C, and from the view of shortening the process, it is preferable to perform it at 40 to 150°C, and more preferable to perform it at 40 to 120°C. As for the heating time, it is not particularly limited, but 1 to 10 minutes or 1 to 5 minutes may be used. When thermal imidation of the amic acid or amic acid ester in the polymer is performed, after the above process, a heating process may be carried out at a temperature range of, for example, 190 to 250°C or 200 to 240°C. The heating time is not particularly limited, but a heating time of 5 to 40 minutes or 5 to 30 minutes may be used.

[0205] <Process (3)>

[0206] Process (3) is a process of irradiating the film obtained in process (2) with polarized ultraviolet light. The wavelength of the ultraviolet light is preferably 200 to 400 nm, and among these, ultraviolet light having a wavelength of 200 to 300 nm is more preferable. In order to improve liquid crystal alignment, the substrate coated with the liquid crystal alignment film may be heated at 50 to 250 ℃ while irradiating with ultraviolet light. Also, the irradiation dose of the above radiation is 1 to 10,000 mJ / cm² 2 It is preferable, and 100 to 5,000 mJ / cm 2It is more preferable. The liquid crystal alignment layer manufactured in this way can stably align liquid crystal molecules in a specific direction.

[0207] The higher the extinction ratio of polarized ultraviolet light, the more desirable it is because it allows for greater anisotropy. Specifically, the extinction ratio of linearly polarized ultraviolet light is preferably 10:1 or higher, and more preferably 20:1 or higher.

[0208] <Process (4)>

[0209] Process (4) is a process of sintering the film obtained in process (3) at a temperature of 100°C or higher and also higher than that of process (2). The sintering temperature is 100°C or higher and is not particularly limited as long as it is higher than the sintering temperature in process (2), but 150 to 300°C is preferred, 150 to 250°C is more preferred, and 200 to 250°C is even more preferred. The sintering time is 5 to 120 minutes, more preferably 5 to 60 minutes, and even more preferably 5 to 30 minutes.

[0210] Since the reliability of the liquid crystal display device may be reduced if the thickness of the liquid crystal alignment film after firing is excessively thin, it is preferable for the thickness to be 5 to 300 nm, and more preferable for the thickness to be 10 to 200 nm.

[0211] In addition, after performing either process (3) or (4) above, the obtained liquid crystal alignment film may be subjected to contact treatment using water or a solvent.

[0212] The solvent used in the above contact treatment is not particularly limited as long as it is a solvent that dissolves the decomposition product generated from the liquid crystal alignment film by irradiation with ultraviolet light. 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, or cyclohexyl acetate. Among these, water, 2-propanol, 1-methoxy-2-propanol, or ethyl lactate are preferred in terms of general utility and solvent safety, and water, 1-methoxy-2-propanol, or ethyl lactate are more preferred. The solvent may be of one type or a combination of two or more types.

[0213] Examples of the above contact treatment, that is, the method of treating a liquid crystal alignment film irradiated with polarized ultraviolet light with water or a solvent, include immersion treatment or spray treatment (also called spray treatment). The treatment time for these treatments is preferably 10 seconds to 1 hour in order to efficiently dissolve the decomposition products generated from the liquid crystal alignment film by ultraviolet light. Among these, it is preferable to perform immersion treatment for 1 to 30 minutes. In addition, the solvent during the above contact treatment may be heated even at room temperature, but preferably 10 to 80°C, and more preferably 20 to 50°C. Furthermore, in terms of the solubility of the decomposition products, ultrasonic treatment or the like may be performed as necessary.

[0214] After the above contact treatment, it is preferable to perform rinsing (also called rinsing) with a low-boiling point solvent such as water, methanol, ethanol, 2-propanol, acetone, or methyl ethyl ketone, or to perform calcination of the liquid crystal alignment film. At that time, either rinsing or calcination may be performed, or both may be performed. The calcination temperature is preferably 150 to 300°C, more preferably 180 to 250°C, and even more preferably 200 to 230°C. In addition, the calcination time is preferably 10 seconds to 30 minutes, more preferably 1 to 10 minutes.

[0215] Liquid crystal alignment layer

[0216] The liquid crystal alignment film of the present invention is obtained from the liquid crystal alignment agent.

[0217] The liquid crystal alignment layer of the present invention is preferred as a liquid crystal alignment layer for a liquid crystal display device of a transverse electric field method such as an IPS method or an FFS method, and is particularly useful as a liquid crystal alignment layer for a liquid crystal display device of an FFS method.

[0218] Liquid Crystal Display

[0219] The liquid crystal display element of the present invention comprises the liquid crystal alignment layer.

[0220] A liquid crystal display element is obtained by obtaining a substrate to which a liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention is attached, manufacturing a liquid crystal cell by a known method, and using the liquid crystal cell.

[0221] As an example of a method for manufacturing a liquid crystal cell, a liquid crystal display device with a passive matrix structure is described. Additionally, it may be a liquid crystal display device with an active matrix structure in which switching elements, such as TFTs (Thin Film Transistors), are formed in each pixel portion constituting the image display.

[0222] Specifically, a transparent glass substrate is prepared, and a common electrode is formed on one substrate and a segment electrode is formed on the other substrate. These electrodes can be, for example, ITO electrodes and are patterned to display a desired image. Subsequently, an insulating film is formed by covering the common electrode and the segment electrode on each substrate. The insulating film can be, for example, a SiO2-TiO2 film formed by the sol-gel method.

[0223] Next, a liquid crystal alignment layer is formed on each substrate, and one substrate is overlapped with the other substrate so that their liquid crystal alignment layer surfaces face each other, and the periphery is bonded with a sealing agent. In the sealing agent, spacers are typically incorporated to control the gap between the substrates, and it is also desirable to distribute spacers for controlling the gap between substrates in the areas where the sealing agent is not formed. An opening is formed in a part of the sealing agent to allow liquid crystal to be filled from the outside. Subsequently, liquid crystal material is injected into the space enclosed by the two substrates and the sealing agent through the opening formed in the sealing agent, and then the opening is sealed with an adhesive. For injection, a vacuum injection method may be used, or a method utilizing capillary action in the atmosphere may be used. Either a positive liquid crystal material or a negative liquid crystal material may be used. Next, a polarizing plate is installed. Specifically, a pair of polarizing plates are attached to the side opposite to the liquid crystal layer of the two substrates.

[0224] By using the manufacturing method of the present invention, afterimages caused by long-term AC driving can be suppressed in liquid crystal display elements of IPS driving method or FFS driving method. In addition, in process (2), by removing the organic solvent in a temperature range of 40 to 150°C and then performing process (3), a liquid crystal alignment film can be obtained with fewer process steps than conventional methods. The liquid crystal alignment agent of the present invention can be particularly preferably used in a method for manufacturing a liquid crystal alignment film comprising a process of removing the organic solvent in a temperature range of 40 to 150°C in process (2) and then performing process (3).

[0225] Examples

[0226] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited thereto. The abbreviations of compounds and methods for measuring each characteristic described below are as follows.

[0227] (menstruum)

[0228] NMP: N-methyl-2-pyrrolidone

[0229] BCS : Butylcellosolve

[0230] (Diamine)

[0231] DA-1 ~ DA-13: Each, compounds represented by the following formulas (DA-1) ~ (DA-13).

[0232] (Tetracarboxylic acid 2 anhydride)

[0233] CA-1 ~ CA-3: Each, a compound (additive) represented by the following formulas (CA-1) ~ (CA-3)

[0234] C-1: Compound represented by the following formula (C-1)

[0235] S-1: A compound represented by the following formula (S-1),

[0236] F-1: Compound represented by the following formula (F-1)

[0237] [Chemical Formula 42]

[0238]

[0239] (In the above formula, Boc represents a tert-butoxycarbonyl group.)

[0240] [Chemical Formula 43]

[0241]

[0242] [Chemical Formula 44]

[0243]

[0244] (In the above formula, Boc represents a tert-butoxycarbonyl group. Fmoc represents a 9-fluorenylmethyloxycarbonyl group.)

[0245] Measurement of Imide Conversion Rate

[0246] 20 mg of polyimide powder was placed in an NMR sample tube (NMR sampling tube standard, φ5 (manufactured by Kusano Kagaku Co., Ltd.)), deuterated dimethyl sulfoxide (DMSO-d6, 0.05% TMS (tetramethylsilane) mixture) (0.53 mL) was added, and the solution was completely dissolved by applying ultrasound. The proton NMR of this solution at 500 MHz was measured using an NMR detector (JNW-ECA500) (manufactured by Nippon Eki Datum Co., Ltd.). The imidation rate was determined by the following formula using the peak integration value of a proton derived from a structure that does not change before and after imidation as a reference proton, and the peak integration value of this proton and the proton peak integration value derived from the NH group of the amic acid appearing around 9.5 ppm to 10.0 ppm.

[0247] Imidization rate (%) = (1 - α·x / y) × 100

[0248] In the above formula, x is the peak integration value of the NH group of the amic acid, y is the peak integration value of the reference proton, and α is the ratio of the number of reference protons to one NH group proton of the amic acid in the case of polyamic acid (imidization rate 0%).

[0249] [Example of polymer synthesis]

[0250] <Synthesized Example 1>

[0251] In a 100 mL branched flask equipped with a stirring device and a nitrogen inlet tube, 5.62 g (19.2 mmol) of DA-2, 4.18 g (10.5 mmol) of DA-10, and 2.92 g (5.24 mmol) of DA-7 were weighed and 50.9 g of NMP was added, and the mixture was dissolved by stirring while introducing nitrogen. While stirring the diamine solution under water cooling, 4.50 g (22.7 mmol) of CA-3 was added, followed by an additional 18.0 g of NMP, and the mixture was stirred at 50 °C for 1 hour under a nitrogen atmosphere. Additionally, 2.63 g (11.7 mmol) of CA-1 was added, NMP was added to achieve a concentration of 20 mass%, and the mixture was stirred at 40 °C for 24 hours to obtain a polyamic acid solution.

[0252] 25.0 g of the polyamic acid solution was aliquoted into a 100 mL Erlenmeyer flask containing a stirrer, 8.33 g of NMP, 2.96 g of acetic anhydride (3 equal amounts relative to the molar amount of polyamic acid), and 0.766 g of pyridine (3 equal amounts relative to the molar amount of polyamic acid) were added, and after stirring at room temperature for 30 minutes, the reaction was carried out at 55 °C for 3 hours. The reaction solution was added to 170 g of methanol, and the resulting precipitate was filtered and separated. After washing the precipitate with methanol, it was dried under reduced pressure at 80 °C to obtain polyimide resin powder (imidization rate: 86%). In addition, 4.00 g of this polyimide resin powder was taken into a 500 mL Erlenmeyer flask containing a stirrer, 29.3 g of NMP was added, and the mixture was dissolved by stirring at 70 °C for 24 hours to obtain a polyimide solution (PI-1).

[0253] <Synthesized Example 2>

[0254] In a 200 mL 4-neck flask equipped with a stirring device and a nitrogen inlet tube, 2.44 g (10.0 mmol) of DA-1, 2.37 g (10.0 mmol) of DA-3, 2.30 g (10.0 mmol) of DA-4, 2.98 g (10.0 mmol) of DA-6, and 3.44 g (10.0 mmol) of DA-9 were weighed and NMP was added to achieve a concentration of 12 mass%, and the mixture was dissolved by stirring while introducing nitrogen. While stirring this diamine solution, 10.6 g (47.2 mmol) of CA-1 was added, NMP was added to achieve a concentration of 12 mass%, and the mixture was stirred at 40 °C for 24 hours to obtain a polyamic acid solution.

[0255] 35 g (8.7 mmol) of the obtained polyamic acid solution was aliquoted into a 100 mL 4-neck flask equipped with a stirring device and a nitrogen inlet tube, 11.7 g of NMP was added, and the mixture was stirred for 30 minutes. To the obtained polyamic acid solution, 2.67 g of acetic anhydride (3 equal amounts relative to the molar amount of polyamic acid) and 0.69 g of pyridine (8 equal amounts relative to the molar amount of polyamic acid) were added, and chemical imidation was performed by heating at 55 °C for 3 hours. The resulting reaction mixture was added to 150 mL of methanol while stirring, the precipitated precipitate was filtered and collected, and the resin powder was washed by repeating the same operation twice. The mixture was then dried under reduced pressure at 60 °C for 12 hours to obtain polyimide resin powder. The imidation rate of this polyimide resin powder was 86%. 3.60 g of the obtained polyimide resin powder was aliquoted into a 100 mL Erlenmeyer flask, NMP was added to achieve a solid content concentration of 12 mass%, and the mixture was dissolved by stirring at 70 °C for 24 hours to obtain a polyimide solution (PI-2).

[0256] <Synthesized Examples 3 to 5>

[0257] Polyimide solutions (PI-3) to (PI-5) were obtained using the same method as in Synthesis Example 2, except that the type and amount of monomer used were changed as described in Table 1 below.

[0258] <Synthesized Example 6>

[0259] In a 200 mL 4-neck flask equipped with a stirring device and a nitrogen inlet tube, 2.69 g (9.0 mmol) of DA-6 and 7.17 g (36.0 mmol) of DA-11 were taken, NMP was added to a concentration of 12 mass%, and dissolved by stirring while introducing nitrogen. While stirring this diamine solution, 12.2 g (41.4 mmol) of CA-2 was added, NMP was added to a concentration of 12 mass%, and the mixture was stirred at 70 °C for 24 hours to obtain a polyamic acid solution (PAA-1).

[0260] In addition, the numbers in parentheses in Table 1 represent, for the tetracarboxylic acid component, the mixing ratio (molar parts) of each compound relative to 100 molar parts of the total amount of tetracarboxylic acid derivatives used in the synthesis, and for the diamine component, the mixing ratio (molar parts) of each compound relative to 100 molar parts of the total amount of diamines used in the synthesis. For the organic solvent, the mixing ratio (mass parts) of each organic solvent relative to 100 mass parts of the total amount of organic solvents used in the preparation of the polyimide solution is indicated.

[0261]

[0262] [Preparation of Liquid Crystal Orientation Agent]

[0263] <Comparative Example 1>

[0264] In a sample tube containing a stirrer, NMP and BCS were added to the polyimide solution (PI-1) obtained in Synthesis Example 1 to dilute it, and S-1, C-1, and F-1 were added in amounts of 1 part by mass, 10 parts by mass, and 15 parts by mass, respectively, relative to 100 parts by mass of polymer solids, and stirred for 30 minutes. In this way, a liquid crystal aligning agent (R1) was obtained having a solid content concentration of 6% of polyimide (PI-1) and a solvent composition of NMP : BCS = 80 : 20 by mass.

[0265] <Examples 1 to 8>

[0266] Liquid crystal alignment agents (1) to (8) were obtained by carrying out the same method as Comparative Example 1, except that the polymer components used were changed as described in Table 2 below. In Table 2, the numbers in parentheses represent the mixing ratio (parts by mass) of each polymer component or additive relative to 100 parts by mass of the total polymer components used to prepare the liquid crystal alignment agent, for polymers and additives. For organic solvents, they represent the mixing ratio (parts by mass) of each organic solvent relative to 100 parts by mass of the total amount of organic solvents used to prepare the liquid crystal alignment agent.

[0267]

[0268] Using the liquid crystal alignment agent obtained as described above, an FFS driving liquid crystal cell was manufactured in the order shown below, and a characteristic evaluation was performed.

[0269] [Composition of FFS driving liquid crystal cell]

[0270] A liquid crystal cell for Fringe Field Switching (FFS) mode comprises a first glass substrate having a Finger on Plate (FOP) electrode layer formed on its surface, the FOP layer consisting of a planar common electrode, an insulating layer, and a comb-shaped pixel electrode, and a second glass substrate having a columnar spacer with a height of 3.5 μm on its surface and an ITO film for anti-static protection formed on its back surface. The pixel electrode has a comb shape in which multiple electrode elements with a width of 3 μm, each having a central portion curved at an internal angle of 160°, are arranged parallel to each other at a distance of 6 μm, and each pixel has a first region and a second region separated by a line connecting the curved portions of the multiple electrode elements.

[0271] In addition, the liquid crystal alignment layer formed on the first glass substrate is aligned such that the direction dividing the inner angle of the pixel curvature equally and the alignment direction of the liquid crystal are orthogonal, and the liquid crystal alignment layer formed on the second glass substrate is aligned such that when a liquid crystal cell is manufactured, the alignment direction of the liquid crystal on the first substrate and the alignment direction of the liquid crystal on the second substrate coincide.

[0272] [Manufacturing of Liquid Crystal Cells]

[0273] A liquid crystal alignment agent filtered through a 1.0 μm filter was applied to the surface of each of the above-mentioned set of glass substrates by spin coating, and dried on a hot plate at 80°C for 2 minutes. Subsequently, a polarizer was interposed on the coating surface, and linearly polarized ultraviolet rays with a wavelength of 254 nm and an extinction ratio of 26:1 were irradiated at a rate of 150 to 350 mJ / cm². 2 After investigation, the substrate was sintered in a hot air circulating oven at 230°C for 30 minutes to obtain two substrates with a liquid crystal alignment film having a thickness of 100 nm.

[0274] Next, a sealant was printed on one side of the substrate to which the above set of liquid crystal alignment films was attached, and the other side of the substrate was laminated so that the liquid crystal alignment film surfaces faced each other, and the sealant was cured to produce an empty cell. Liquid crystal (Merck, MLC-3019) was vacuum injected into this empty cell at room temperature by a vacuum injection method, and the injection port was sealed to obtain an FFS driving liquid crystal cell. After that, the obtained liquid crystal cell was heated at 120°C for 1 hour (hereinafter also referred to as "ISO treatment"), left overnight, and then used for each evaluation.

[0275] Liquid Crystal Orientation Evaluation

[0276] Evaluation was conducted using liquid crystal cells prior to ISO treatment, defining those with initial flow orientation as “defective” and those without initial flow orientation as “good.”

[0277] <Evaluation of In-plane Contrast Uniformity>

[0278] The twist angle of the liquid crystal display element was evaluated using the OPTIPRO-micro manufactured by Syntec Co., Ltd. The manufactured liquid crystal cell was installed on a measurement stage, and the standard deviation was calculated by measuring 20 points within the first pixel plane in a state where no voltage was applied. The evaluation was conducted by defining the standard deviation of the twist angle as "defective" if it was 0.5 or higher, and "good" if it was less than 0.5.

[0279] <Evaluation Results>

[0280] The evaluation results for the liquid crystal display elements obtained using the liquid crystal alignment agents (1) to (8) and (R1) obtained in Examples 1 to 8 and Comparative Example 1 above are shown in Table 3.

[0281]

[0282] Industrial applicability

[0283] The liquid crystal alignment agent of the present invention is widely used in liquid crystal display devices of the TN method, VA method, etc., and especially in the IPS method, FFS method, etc.

[0284] In addition, the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2020-039387 filed on March 6, 2020 and Japanese Patent Application No. 2020-123014 filed on July 17, 2020 are incorporated herein by reference and accepted as disclosure of the specification of the present invention.

Claims

Claim 1 A liquid crystal orientation agent characterized by containing a polymer (A) in which the imidization rate of the imidization polymer is 80 to 95%, as an imidized polymer of a polyimide precursor containing a repeating unit (a0) represented by the following formula (0) and a repeating unit (a1) represented by the following formula (1). (In formulas (0) and (1), X represents a tetravalent organic group represented by the following formula (g), Y represents a divalent organic group derived from an aromatic diamine (d0) satisfying conditions (1) and (2) below, Y is a divalent organic group derived from 2,6-diaminotoluene, 3,3'-diaminodiphenylmethane or 1,5-bis(4-aminophenoxy)pentane, or a compound represented by the following formulas (DA-4), (DA-5), (DA-8), (DA-11), or (DA-13), Y1 represents a divalent organic group derived from an aromatic diamine (d1) satisfying conditions (1) and (3) below, R and Z each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and X may be the same or different.) (In formula (g), 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 definitions, and also, a portion of the -CH2- included in the alkyl group, alkenyl group, alkynyl group and the monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom may be substituted with -O-, and * indicates a bond loss.) Condition (1): Does not have a side chain group having 6 or more carbon atoms. Condition (2): The two carbon-nitrogen bond axes originating from the amino group are not parallel to each other. Condition (3): The two carbon-nitrogen bonds originating from the amino group The connecting axes are parallel to each other and have a substructure represented by the following equation (O). (In formula (O), Ar independently represents a benzene ring, a biphenyl structure, or a naphthalene ring, any hydrogen atom on the ring may be substituted with a halogen atom or a monovalent organic group, and Q2 is -(CH2) n - (n is an integer from 2 to 18), or the above -(CH2) n - represents a group formed by substituting any -CH2- with -O-, -C(=O)-, or -OC(=O)-, and * represents an associative hand.) Claim 2 delete Claim 3 A liquid crystal alignment agent according to claim 1, wherein Y1 in the above formula (1) is a divalent organic group derived from a diamine represented by the following formulas (d1-1) to (d1-14). Claim 4 A liquid crystal orientation agent according to claim 1, wherein the sum of the repeating unit (a0), the repeating unit (a1), and their imidized repeating units is 5 mol% or more with respect to the total repeating unit. Claim 5 A liquid crystal alignment agent according to claim 1, wherein the tetravalent organic group represented by the above formula (g) is a tetravalent organic group represented by any one of the following formulas (g-1) to (g-5). (In equations (g-1) through (g-5), * indicates a bonding hand.) Claim 6 A liquid crystal orientation agent according to claim 1, wherein the polymer (A) is an imidized polymer of a polyimide precursor having a repeating unit (a2) represented by the following formula (2) which is further different from the repeating unit (a0) or (a1). (In the formula, X2 represents a tetravalent organic group, Y2 represents a divalent organic group derived from an aromatic diamine that does not have a side chain with 6 or more carbon atoms, and R and Z have the same meaning as R and Z in the above formula (0).) Claim 7 A liquid crystal orientation agent according to claim 1, wherein either or both of the aromatic diamine (d0) and the aromatic diamine (d1) are aromatic diamines having 4 to 40 carbon atoms. Claim 8 In claim 1, a liquid crystal alignment agent for photo-alignment method. Claim 9 A liquid crystal alignment film obtained from a liquid crystal alignment agent described in any one of claims 1 and 3 to 8. Claim 10 A liquid crystal display element having a liquid crystal alignment layer as described in claim 9. Claim 11 A method for manufacturing a liquid crystal alignment film comprising the following processes (1) to (3): Process (1): A process of applying a liquid crystal alignment agent described in any one of claims 1 and 3 to 8 onto a substrate Process (2): A process of heating the liquid crystal alignment agent applied in process (1) to obtain a film Process (3): A process of irradiating the film obtained in process (2) with polarized ultraviolet light Claim 12 A method for manufacturing a liquid crystal alignment film according to claim 11, further comprising the following process (4): Process (4): A process of firing the film obtained in process (3) at a temperature of 100°C or higher, and also at a higher temperature than in process (2). Claim 13 In claim 11, the above process (2) is a method for manufacturing a liquid crystal alignment film, wherein the process is a process of obtaining a film by heating in a temperature range of 40 to 180 ℃. Claim 14 A liquid crystal display element having a liquid crystal alignment layer obtained by the method for manufacturing a liquid crystal alignment layer described in claim 11.

Images