Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element using the same

Abstract

The present invention provides a liquid crystal alignment agent that can form a liquid crystal alignment film with less afterimages from residual DC and AC afterimages, easy reprocessing, and high transmittance. The liquid crystal alignment agent of the present invention is characterized in that it contains the following (A) components and (B) components. (A) component: a polymer (A) having a repeating unit represented by the following formula (1). (B) component: a polymer (B) having a repeating unit represented by the following formula (2) and a repeating unit represented by the following formula (3). (X1 is a tetravalent organic group; Y1 is a divalent organic group; X2 and X3 are tetravalent organic groups derived from alicyclic tetracarboxylic dianhydride or non-cyclic aliphatic tetracarboxylic dianhydride; R2 is a hydrogen atom, etc.; Z 21 , Z 22 , Z 31 , Z 32 is a hydrogen atom, etc.; Y3 is a divalent organic group having a partial structure represented by the following formula (n); R3 is a hydrogen atom, etc.; Q2 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; Q3 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; * is a bonding bond. )

Description

Technical Field

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

[0002] In the past, liquid crystal devices were widely used as display units for personal computers, smart phones, mobile phones, television monitors, etc. Liquid crystal devices include, for example: a liquid crystal layer sandwiched between an element substrate and a color filter substrate; pixel electrodes and common electrodes for applying an electric field to the liquid crystal layer; an orientation film for controlling the orientation of liquid crystal molecules in the liquid crystal layer; and a thin film transistor (TFT: Thin Film Transistor) for switching the electrical signal supplied to the pixel electrode. As driving methods for liquid crystal molecules, known are longitudinal electric field methods such as TN (Twisted Nematic) method and VA (Vertical Alignment) method; and transverse electric field methods such as IPS (In-Plane Switching) method and FFS (FringeField Switching) method (Patent Document 1).

[0003] Generally, in the transverse electric field method in which electrodes are formed only on one side of a substrate and an electric field is applied in a direction parallel to the substrate, compared with the conventional longitudinal electric field method in which a voltage is applied to electrodes formed on upper and lower substrates to drive liquid crystal, a liquid crystal display element having a wide viewing angle characteristic and capable of high-quality display is known. As a method for orienting liquid crystal in a certain direction, there is a method of forming a polymer film such as polyimide on a substrate and rubbing the surface with a cloth to perform a so-called brushing treatment, which is also widely used in industry.

[0004] The liquid crystal alignment film, which is a component of the liquid crystal display element, is a film used to uniformly align the liquid crystal, but it requires not only the uniformity of the orientation of the liquid crystal but also various characteristics. For example, there are problems such as the following: due to the voltage driving the liquid crystal, charges are accumulated in the liquid crystal alignment film, and these accumulated charges disturb the orientation of the liquid crystal, or affect the display in the form of afterimages and afterimages (hereinafter referred to as afterimages derived from residual DC), which significantly reduces the display quality level of the liquid crystal display element. Therefore, a liquid crystal alignment agent that overcomes these problems has been proposed (Patent Document 2).

[0005] In addition, in the IPS mode and the FFS driving mode, the stability of the liquid crystal orientation also becomes important. If the stability of the orientation is small, the liquid crystal cannot return to its initial state when the liquid crystal is driven for a long time, which causes a reduction in contrast and afterimage (hereinafter referred to as AC afterimage). As a method for solving the above problems, in Patent Document 3, the following liquid crystal orientation agent is disclosed, which contains a polymer and a specific compound, and the polymer is selected from the group consisting of a polyamic acid containing a specific tetracarboxylic dianhydride and a specific diamine and an imidized polymer thereof.

[0006] In addition, economic efficiency in the production process is very important, so it is also required to be easy to recycle the element substrate. That is, after the liquid crystal alignment film is formed by the liquid crystal alignment agent, when the orientation is inspected and defects occur, it is required to be able to easily implement the reprocessing process of removing the liquid crystal alignment film from the substrate and recovering the substrate.

[0007] In addition, in the IPS method and the FFS driving method, a liquid crystal material having a positive Δε (p-type liquid crystal material) or a liquid crystal material having a negative Δε (n-type liquid crystal material) is generally used (see Patent Document 4).

[0008] Compared with liquid crystal display elements using n-type liquid crystal materials, when p-type liquid crystal materials are used for liquid crystal display elements, the amount of backlight that can pass through the panel tends to deteriorate. From the perspective of further improving the transmittance, a liquid crystal alignment film with high transmittance is required.

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent Application Publication No. 2013-167782

[0012] Patent Document 2: WO2002 / 33481 Pamphlet

[0013] Patent Document 3: WO2016 / 063834 Pamphlet

[0014] Patent Document 4: WO2015 / 056644 Pamphlet Summary of the invention

[0015] Problems to be solved by the invention

[0016] Furthermore, in order to obtain a panel with high contrast, black quality when no voltage is applied is also important, and a liquid crystal alignment film having a higher black quality is required without causing defects due to a rubbing process or a decrease in black quality due to insufficient orientation.

[0017] On the other hand, when an n-type liquid crystal material is used, a decrease in voltage holding ratio, which causes display failure, is likely to occur, and therefore a liquid crystal alignment film having a high voltage holding ratio is required.

[0018] It is not necessarily possible to say that the liquid crystal aligning agents proposed in the past can fully solve all the above problems. In addition, when the liquid crystal aligning agents proposed in Patent Documents 2 and 3 are used, there is also a problem that the light transmittance of the obtained liquid crystal aligning film becomes low, and there is room for further improvement.

[0019] The present invention is completed based on the above situation, and its purpose is to provide a liquid crystal alignment agent that can form a liquid crystal alignment film with less afterimages from residual DC and AC afterimages, high transmittance, contrast and voltage retention characteristics, and good reprocessability.

[0020] Solutions for solving problems

[0021] The present inventors have conducted intensive studies and, as a result, have found that the above-mentioned problems can be solved by using a liquid crystal aligning agent containing a combination of components consisting of specific polymers, thereby completing the present invention.

[0022] The present invention has the following aspects.

[0023] A liquid crystal aligning agent characterized by containing the following (A) component and (B) component.

[0024] Component (A): A polymer (A) having a repeating unit represented by the following formula (1).

[0025] Component (B): a polymer (B) having a repeating unit represented by the following formula (2) and a repeating unit represented by the following formula (3).

[0026]

[0027] (X1 is a tetravalent organic group; Y1 is a divalent organic group.)

[0028]

[0029] (X2 is a tetravalent organic group derived from alicyclic tetracarboxylic dianhydride or non-cyclic aliphatic tetracarboxylic dianhydride. R2 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Z 21 , Z 22 Each independently represents a hydrogen atom or a monovalent organic group. )

[0030]

[0031] (X3 is a tetravalent organic group derived from alicyclic tetracarboxylic dianhydride or non-cyclic aliphatic tetracarboxylic dianhydride. Y3 is a divalent organic group having a partial structure represented by the following formula (n). R3 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; Z 31 , Z 32 Respectively with Z in the above formula (2) 21 , Z 22 Synonymous.)

[0032]

[0033] (Q2 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and Q3 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. * represents a bonding bond.)

[0034] Effects of the Invention

[0035] According to the liquid crystal alignment agent of the present invention, a liquid crystal alignment film having high transmittance and voltage holding characteristics and good reprocessability can be obtained. In addition, according to the liquid crystal alignment agent of the present invention, a liquid crystal display element that is not prone to residual images and AC residual images from residual DC, has few display defects, and has excellent contrast can be obtained. DETAILED DESCRIPTION

[0036] Hereinafter, each component contained in the liquid crystal aligning agent of this indication and other components mix|blended arbitrarily as needed are demonstrated.

[0037] <(A)Component>

[0038] The liquid crystal aligning agent of the present invention contains a component (A) composed of a polymer (A) having a repeating unit represented by the above formula (1). By containing the component (A), a liquid crystal aligning film with less AC afterimage and high transmittance can be obtained, and a liquid crystal display element with high voltage holding ratio and suppressed contrast reduction can be obtained.

[0039] In the above formula (1), X1 and Y1 are as defined above. As X1 in formula (1), a tetravalent organic group derived from tetracarboxylic dianhydride can be listed. For example, a tetravalent organic group derived from aromatic tetracarboxylic dianhydride, non-cyclic aliphatic tetracarboxylic dianhydride, and alicyclic tetracarboxylic dianhydride can be listed. Y1 in formula (1) is a divalent organic group derived from a diamine compound.

[0040] Here, aromatic tetracarboxylic dianhydride refers to an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups including at least one carboxyl group bonded to an aromatic ring. Non-cyclic aliphatic tetracarboxylic dianhydride refers to an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. Among them, it is not necessary to be composed only of a chain hydrocarbon structure, and a part of it may also have an alicyclic structure and an aromatic ring structure. Alicyclic tetracarboxylic dianhydride refers to 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 are bonded to an aromatic ring. In addition, it is not necessary to be composed only of an alicyclic structure, and a part of it may also have a chain hydrocarbon structure and an aromatic ring structure.

[0041] From the viewpoint of improving the solubility of the polymer (A), X1 is preferably a tetravalent organic group selected from the group consisting of the following formulae (4a) to (4n), the following formula (5a) and the following formula (6a).

[0042]

[0043] (x and y are each independently a single bond, -O-, -CO-, -COO-, an alkylene group having 1 to 5 carbon atoms, 1,4-phenylene, a sulfonyl group or an amide group. 1 ~Z 6 Each independently represents a hydrogen atom, a methyl group, an ethyl group, a propyl group, a chlorine atom or a benzene ring. j and k are integers of 0 or 1. m is an integer of 1 to 5. * represents a bonding bond. )

[0044] As a preferred specific example of the above formula (4a) from the viewpoint of reducing AC afterimages, there can be mentioned structures represented by any of the following formulas (4a-1) to (4a-4).

[0045]

[0046] Examples of the alkylene group having 1 to 5 carbon atoms in x and y in the above formulae (5a) and (6a) include a methylene group, an ethylene group, a 1,3-propylene group, a 1,4-butylene group, and a 1,5-pentylene group.

[0047] From the viewpoint of reducing AC afterimages and ensuring solubility, X1 in the above formula (1) is preferably a tetravalent organic group selected from the group consisting of the above formulae (4a) to (4h), (4j), and (4l) to (4n).

[0048] The diamine compound of Y1 in the formula (1) that can be used to form the polymer (A) is not particularly limited, but specific examples thereof include the following non-cyclic aliphatic diamines, alicyclic diamines, and aromatic diamines.

[0049] Examples of the non-cyclic aliphatic diamine include meta-xylylenediamine, ethylenediamine, 1,3-propylenediamine, tetramethylenediamine, hexamethylenediamine, and 1,3-bis(3-aminopropyl)-tetramethyldisiloxane.

[0050] Examples of the alicyclic diamine include p-cyclohexanediamine and 4,4′-methylenebis(cyclohexylamine).

[0051] As the aromatic diamine, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminoazobenzene, 3,5-diaminobenzoic acid, bis(4-aminophenyl)amine, N,N-bis(4-aminophenyl)methylamine, 1,4-bis(4-aminophenyl)-piperazine, N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine, 2, 2'-dimethyl-4,4'-diaminobiphenyl, 1,3-bis(4-aminophenyloxy)benzene, 1,4-bis(4-aminophenyloxy)benzene, bis[4-(4-aminophenyloxy)phenyl]ether, 4,4'-bis(4-aminophenyloxy)biphenyl, 4-(4-aminophenyloxycarbonyl)-1-(4-aminophenyl)piperidine, 4,4'-[4,4'-propane-1,3-diylbis(piperidine-1,4-diyl)]diphenylamine, etc.

[0052] In addition, examples of diamine compounds that can be used to form Y1 in formula (1) include diamines represented by the following formula (Q) described in International Publication (hereinafter referred to as WO) No. 2015 / 122413, and diamines in which two amino groups are bonded to a divalent organic group having a partial structure represented by the following formula (H).

[0053]

[0054] (R 11 represents a hydrogen atom, a methyl group or a tert-butyloxycarbonyl group, two R 12 Each independently represents a hydrogen atom or a methyl group. 11 represents a straight-chain alkylene group having 1 to 5 carbon atoms. Specific examples of the straight-chain alkylene group include methylene, ethylene, trimethylene, tetramethylene, and pentamethylene.

[0055]

[0056] (R 13 -NRCO-, -COO-, -OCO-, -NRCONR-, -CONR- or -(CH2) n-(n is an integer of 1 to 20), when n is 2 to 20, any -CH2- is optionally substituted by -O-, -COO-, -OCO-, -ND-, -NRCO-, -CONR-, -NRCONR-, -NRCOO- or -OCOO- under the condition that they are not adjacent to each other. D represents a thermally detachable group, and R represents a hydrogen atom or a monovalent organic group. R 14 is a single bond or a benzene ring, and any hydrogen atom on the benzene ring is optionally substituted by a monovalent organic group. *1 and *2 represent a bond. 14 In the case of a single bond, *2 is bonded to the nitrogen atom in the amino group. 14 In the case of a benzene ring, R 13 Optionally a single bond. )

[0057] From the viewpoint of reducing AC afterimages, Y1 in the above formula (1) is preferably a divalent organic group having a partial structure represented by the above formula (H). In this case, R 14 When it is a single bond, *2 is bonded to the nitrogen atom in the imide ring. Among them, Y1 in the above formula (1) is preferably a divalent organic group having a partial structure represented by any of the following formulae (H-1) to (H-14).

[0058]

[0059] (*1 and *2 represent a bond, and *2 is bonded to a nitrogen atom in the imide ring. Boc in this specification represents a tert-butoxycarbonyl group.)

[0060] From the viewpoint of easy synthesis, Y1 in the above formula (1) is preferably a divalent organic group represented by the above formulas (H-1) to (H-14) or the following formula (MH-1) or (MH-2).

[0061]

[0062] (*1Bonded to the nitrogen atom in the imide ring.)

[0063] The polymer (A) may further have a repeating unit represented by the following formula (PA-1) in addition to the repeating unit represented by the above formula (1).

[0064]

[0065] In the formula (PA-1), X1 and Y1 have the same meanings as X1 and Y1 in the formula (1), including preferred embodiments. R1 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. 11 , Z 12 Respectively with Z in the above formula (2) 21 , Z 22Synonymous.

[0066] Specific examples of the alkyl group having 1 to 5 carbon atoms in R1 include methyl, ethyl, propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, and n-pentyl. It should be noted that "i-" represents iso, "s-" represents secondary, and "t-" represents tertiary. From the perspective of ease of imidization by heating, R1 is preferably a hydrogen atom or a methyl group.

[0067] From the perspective of less AC afterimage, Z 11 , Z 12 Each independently preferably is a hydrogen atom or a methyl group.

[0068] The polymer (A) may have a structure represented by the following formula (6) at its terminal. Such a structure is preferred in that the layer separation with the polymer (B) described later is promoted and a liquid crystal alignment film having reduced AC afterimages and afterimages derived from residual DC is obtained.

[0069]

[0070] (* represents a bond, and Z represents a monovalent organic group.)

[0071] Examples of Z in the formula (6) include methyl, ethyl, propyl, 2,2,2-trichloroethyl, 2-trimethylsilylethyl, 1,1-dimethylpropynyl, 1-methyl-1-phenylethyl, 1-methyl-1-(4-biphenylyl)ethyl, 1,1-dimethyl-2-haloethyl, 1,1-dimethyl-2-cyanoethyl, tert-butyl, cyclobutyl, 1-methylcyclobutyl, 1-adamantyl, vinyl, allyl, cinnamyl, 8-quinolyl, N-hydroxypiperidinyl, benzyl, p-nitrobenzyl, 3,4-dimethoxy-6-nitrobenzyl, 2,4-dichlorobenzyl, and 9-fluorenylmethyl.

[0072] As Z, from the viewpoint of high effect obtained, a methyl group, an ethyl group, a propyl group, a tert-butyl group, a 2,2,2-trichloroethyl group, a 2-trimethylsilylethyl group, a 1,1-dimethylpropynyl group, a 1-methyl-1-(4-biphenylyl)ethyl group, a 1,1-dimethyl-2-haloethyl group, a 1,1-dimethyl-2-cyanoethyl group, a cyclobutyl group, a 1-methylcyclobutyl group, a vinyl group, an allyl group, a cinnamyl group, an N-hydroxypiperidinyl group, a benzyl group, and a 9-fluorenylmethyl group are preferred.

[0073] From the viewpoint of less AC afterimage, it is preferred that the polymer (A) contains 1 to 95 mol % of the repeating unit represented by the above formula (1) relative to the total repeating units possessed by the polymer (A), and it is more preferred that the polymer (A) contains 50 to 90 mol % of the repeating unit represented by the above formula (1) relative to the total repeating units possessed by the polymer (A).

[0074] <(B) Ingredient>

[0075] The liquid crystal aligning agent of the present invention contains a component (B) composed of a polymer (B) having a repeating unit represented by the above formula (2) and a repeating unit represented by the above formula (3). By adopting such a structure, a liquid crystal aligning film having high transmittance and reduced afterimages due to residual DC can be obtained. In the above formulas (2) and (3), X2, X3, Y3, R2, R3, Z 21 , Z 22 , Z 31 , Z 32 As defined above.

[0076] Z in the above formula (2) 21 , Z 22 The monovalent organic group in is an alkyl group having 1 to 10 carbon atoms which may have a substituent, an alkenyl group having 2 to 10 carbon atoms which may have a substituent, an alkynyl group having 2 to 10 carbon atoms which may have a substituent, a tert-butoxycarbonyl group or a 9-fluorenylmethoxycarbonyl group.

[0077] As the above Z 21 , Z 22 Specific examples of the alkyl group having 1 to 10 carbon atoms include, in addition to the specific examples of the alkyl group having 1 to 5 carbon atoms exemplified in R1 above, hexyl, heptyl, octyl, nonyl, decyl, etc. 21 , Z 22 Specific examples of alkenyl groups having 2 to 10 carbon atoms include vinyl, propenyl, butenyl, etc., which may be linear or branched. 21 , Z 22 Specific examples of the alkynyl group having 2 to 10 carbon atoms include ethynyl, 1-propynyl, and 2-propynyl.

[0078] Z 21 , Z 22 It may have a substituent, and examples of the substituent include a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), a hydroxyl group, a cyano group, an alkoxy group, and the like.

[0079] Specific examples of the alkyl group having 1 to 5 carbon atoms in R2 and R3 include the structures exemplified in R1 of the above formula (PA-1). In view of the ease of imidization by heating, R2 and R3 are each independently preferably a hydrogen atom or a methyl group.

[0080] From the perspective of less AC afterimage, Z 21 , Z 22 , Z 31 , Z 32 Preferably, they are each independently a hydrogen atom or a methyl group.

[0081] As the tetravalent organic group derived from alicyclic tetracarboxylic dianhydride or non-cyclic aliphatic tetracarboxylic dianhydride of X2 and X3, the tetravalent organic group derived from alicyclic tetracarboxylic dianhydride or non-cyclic aliphatic tetracarboxylic dianhydride exemplified in X1 above can be cited. From the viewpoint of suppressing AC residual image, X2 and X3 are preferably tetravalent organic groups selected from the group consisting of the above formulae (4a) to (4n).

[0082] As the alkyl group with 1 to 3 carbon atoms of Q2 and Q3 in the above formula (n), methyl, ethyl, propyl, etc. can be listed. From the viewpoint of improving the transmittance of the liquid crystal alignment film, suppressing AC residual images and residual images derived from residual DC, Q2 and Q3 are preferably methyl groups. It should be noted that any hydrogen atom of the benzene ring in formula (n) is optionally substituted by a monovalent organic group, and as the monovalent organic group, alkyl, alkenyl, alkoxy, fluoroalkyl, fluoroalkenyl or fluoroalkoxy, etc. having 1 to 3 carbon atoms can be listed.

[0083] In the above formula (n), the bonding position of the group "-NQ3-Ph-" (Ph represents a phenylene group) is preferably bonded to the 3-position of the carbazole skeleton from the viewpoint of less steric hindrance.

[0084] From the viewpoint of reducing afterimages due to residual DC, the divalent organic group having a partial structure represented by the above formula (n) is preferably a divalent organic group selected from the group consisting of the following formulae (n-1) to (n-3).

[0085]

[0086] In formulas (n-1) to (n-3), Q 2 , Q 3 Including preferred specific examples, respectively with Q of the above formula (n) 2 , Q 3 Synonymous. 4 Each independently represents a single bond or a structure of the following formula (Ar), and n represents an integer of 1 to 3. * represents a bond. In addition, any hydrogen atom of the benzene ring may be substituted with a monovalent organic group as in the case of the above formula (n).

[0087]

[0088] In formula (Ar), Q 5 It represents a single bond, -O-, -COO-, -OCO-, -(CH2) l -, -O(CH2) m The divalent organic group in the group consisting of O-, -CONQ- and -NQCO-, k represents an integer of 1 to 5. Q represents hydrogen or a monovalent organic group, and l and m represent integers of 1 to 5. *1 and *2 represent a bond, and *1 is bonded to the benzene ring in formula (n-1) to formula (n-3).

[0089] Examples of the monovalent organic group in Q of the above formula (Ar) include alkyl groups having 1 to 3 carbon atoms.

[0090] From the viewpoint of easy synthesis, the divalent organic group having the partial structure represented by the above formula (n) is preferably a divalent organic group represented by any of the following formulae (cbz-1) to (cbz-6). * represents a bonding bond.

[0091]

[0092]

[0093] From the viewpoint of reducing afterimages due to residual DC, the polymer (B) may further have at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (4) and a repeating unit represented by the following formula (5).

[0094]

[0095] In formula (4) and (5), X4 and X5 are tetravalent organic groups derived from aromatic tetracarboxylic dianhydride, and examples thereof include the tetravalent organic groups derived from aromatic tetracarboxylic dianhydride exemplified in X1 of the above formula (1). From the viewpoint of less AC afterimage and less afterimage derived from residual DC, X4 and X5 are preferably tetravalent organic groups selected from the group consisting of the above formula (5a) and (6a).

[0096] More preferred specific examples of the tetravalent organic group represented by the above formulae (5a) and (6a) include structures represented by any of the following formulae (a-1) to (a-17).

[0097]

[0098] (* indicates a bond.)

[0099] In formula (4) and (5), R4, including preferred embodiments, has the same meaning as R2 in formula (2), and Z 41 , Z 42 Including the preferred embodiment, respectively with Z of the above formula (2) 21 , Z 22 Y5, including preferred embodiments, has the same meaning as Y3 in the above formula (3); R5, including preferred embodiments, has the same meaning as R3 in the above formula (3); Z 51 , Z 52 Including the preferred embodiment, respectively with Z of the above formula (3) 31 , Z 32 Synonymous.

[0100] When the polymer (B) has at least one repeating unit selected from the group consisting of the repeating unit represented by the above formula (4) and the repeating unit represented by the above formula (5), from the viewpoint of obtaining high transmittance, the total amount of the repeating units of the formula (4) and the formula (5) is preferably 0.1 to 30 mol % of the total repeating units, and more preferably 1 to 25 mol % of the total repeating units.

[0101] The polymer (B) may further have a repeating unit represented by the following formula (PA-2) in addition to the repeating unit represented by the above formula (2), the repeating unit represented by the above formula (3), the repeating unit represented by the above formula (4), and the repeating unit represented by the above formula (5).

[0102]

[0103] In formula (PA-2), X6 represents a tetravalent organic group, and Y6 represents a divalent organic group. In the case where X6 is a tetravalent organic group derived from alicyclic tetracarboxylic dianhydride, non-cyclic aliphatic tetracarboxylic dianhydride or aromatic tetracarboxylic dianhydride, Y6 represents a structure other than a phenylene group or a divalent organic group having a partial structure represented by formula (n). R6, including preferred embodiments, has the same meaning as R2 in formula (2), and Z 61 , Z 62 Including the preferred embodiment and Z of the above formula (2) 21 , Z 22 Synonymous.

[0104] Specific examples of X6 include: tetravalent organic groups derived from aromatic tetracarboxylic dianhydride, non-cyclic aliphatic tetracarboxylic dianhydride or alicyclic tetracarboxylic dianhydride as exemplified in X1 of the above formula (1); tetravalent organic groups derived from tetracarboxylic dianhydride described in paragraphs

[0036] to

[0052] of JP-A-2010-156953; and the like.

[0105] Specific examples of Y6 include the following divalent organic groups (a) to (d), in addition to the divalent organic groups derived from the diamines exemplified in Y1 of the above formula (1).

[0106] The divalent organic group derived from the diamine having a pyrrole structure described in WO2017 / 126627 is preferably a divalent organic group (a) derived from a diamine represented by the following formula (pr).

[0107]

[0108] (R 1 represents a hydrogen atom, a fluorine atom, a cyano group, a hydroxyl group or a methyl group. 2 Each independently represents a single bond or a group "*1-R 3 -Ph-*2”,R 3 It represents a single bond, -O-, -COO-, -OCO-, -(CH2) l -, -O(CH2) m A divalent organic group in the group consisting of O-, -CONH- and -NHCO- (l, m are integers of 1 to 5, *1 represents a site bonded to the benzene ring in the formula (pr), and *2 represents a site bonded to the amino group in the formula (pr). Ph represents a phenylene group. n represents an integer of 1 to 3.)

[0109] The divalent organic group derived from the diamine having a pyrrole structure described in WO2018 / 062197 is preferably a divalent organic group (b) derived from a diamine represented by the following formula (pn).

[0110]

[0111] (R 1 , R 2 represents a hydrogen atom or a methyl group. 3 Each independently represents a single bond or a group "*1-R 4 -Ph-*2”,R 4 It represents a single bond, -O-, -COO-, -OCO-, -(CH2) l -, -O(CH2) m A divalent organic group in the group consisting of O-, -CONH- and -NHCO- (l, m are integers of 1 to 5, *1 represents a site bonded to the benzene ring in the formula (pn), and *2 represents a site bonded to the amino group in the formula (pn). Ph represents a phenylene group. n represents an integer of 1 to 3.)

[0112] The divalent organic group derived from the diamine having a thiophene or furan structure described in WO2018 / 092759 is preferably a divalent organic group (c) derived from a diamine represented by the following formula (sf).

[0113]

[0114] (Y 1 represents a sulfur atom or an oxygen atom. R2 each independently represents a single bond or a group "*1-R 5 -Ph-*2”,R 5 It represents a single bond, -O-, -COO-, -OCO-, -(CH2) l -, -O(CH2) m A divalent organic group in the group consisting of O-, -CONH- and -NHCO- (l, m are integers of 1 to 5, *1 represents a site bonded to the benzene ring in the formula (pn), and *2 represents a site bonded to the amino group in the formula (pn). Ph represents a phenylene group. n represents 1 to 3.)

[0115] The divalent organic group (d) described in paragraphs

[0013] to

[0030] of WO2018-181566.

[0116] In the liquid crystal aligning agent of the present invention, from the viewpoint of less AC residual image and residual image derived from residual DC, the content ratio of the above-mentioned polymer (A) and the above-mentioned polymer (B) is preferably 5 / 95 to 95 / 5 in terms of the mass ratio of [polymer (A)] / [polymer (B)]. From the viewpoint of obtaining a liquid crystal aligning film with high reproducibility, the mass ratio of [polymer (A)] / [polymer (B)] is more preferably 10 / 90 to 90 / 10, and further preferably 20 / 80 to 80 / 20.

[0117] <Method for producing polymers (A) and (B)>

[0118] The polymer (A), polymer (B), or the raw material intermediates thereof, that is, polyamic acid, polyamic acid ester, and polyimide as polyimide precursors, are obtained by known methods. For example, they can be synthesized by the methods shown below.

[0119] (Method for producing polyamic acid)

[0120] The polyamic acid can be synthesized by reacting tetracarboxylic dianhydride and diamine in the presence of an organic solvent at -20 to 150°C, preferably at 0 to 50°C, for 30 minutes to 24 hours, preferably for 1 to 12 hours.

[0121] From the solubility of monomers and polymers, the organic solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone or γ-butyrolactone, which can be used alone or in combination of two or more. From the viewpoint of not easily causing the precipitation of the polymer and easily obtaining a high molecular weight substance, the concentration of the polymer is preferably 1 to 30% by mass, more preferably 5 to 20% by mass.

[0122] The polyamic acid obtained as described above can be recovered by injecting the reaction solution into a poor solvent while fully stirring the reaction solution, so that the polymer is precipitated. In addition, precipitation is performed several times, and after washing with a poor solvent, the purified polyamic acid powder can be obtained at room temperature or by heating and drying. The poor solvent is not particularly limited, and examples thereof include water, methanol, ethanol, hexane, butyl cellosolve, acetone, toluene, etc.

[0123] The polyamic acid ester which is a polyimide precursor used in the present invention can be synthesized by, for example, the method (1), (2) or (3) shown below.

[0124] (1) Synthesis from polyamic acid

[0125] Polyamic acid ester can be synthesized by esterifying a polyamic acid obtained from tetracarboxylic dianhydride and diamine.

[0126] Specifically, the polyamic acid and the esterification agent can be reacted in the presence of an organic solvent at -20 to 150°C, preferably at 0 to 50°C, for 30 minutes to 24 hours, preferably for 1 to 4 hours.

[0127] As the esterifying agent, an esterifying agent that can be easily removed by purification is preferred, and examples thereof include: N,N-dimethylformamide dimethyl acetal, N,N-dimethylformamide di-tert-butyl acetal, 1-methyl-3-p-tolyltriazene, 4-(4,6-dimethoxy-1,3,5-triazine-2-yl)-4-methylmorpholinium chloride, etc. The amount of the esterifying agent added is preferably 2 to 6 molar equivalents relative to 1 mole of the repeating unit of the polyamic acid.

[0128] From the solubility of the polymer, the solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone or γ-butyrolactone, which can be used alone or in combination of two or more. From the viewpoint of not easily causing the precipitation of the polymer and easily obtaining a high molecular weight substance, the concentration during synthesis is preferably 1 to 30% by mass, more preferably 5 to 20% by mass.

[0129] (2) Synthesis by reaction of tetracarboxylic acid diester dichloride and diamine

[0130] Polyamic acid ester can be synthesized from tetracarboxylic acid diester dichloride and diamine. Specifically, it can be synthesized by reacting tetracarboxylic acid diester dichloride and diamine in the presence of a base and an organic solvent at -20 to 150°C, preferably at 0 to 50°C for 30 minutes to 24 hours, preferably for 1 to 4 hours.

[0131] The base may be pyridine, triethylamine or the like, but pyridine is preferred for mild reaction. The amount of the base added is preferably 2 to 4 times the molar amount of the tetracarboxylic acid diester dichloride from the viewpoint of easy removal and easy acquisition of a high molecular weight product.

[0132] From the solubility of monomers and polymers, the solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone, which can be used alone or in combination of two or more. From the viewpoint of not easily producing polymer precipitation and easily obtaining high molecular weight substances, the polymer concentration during synthesis is preferably 1 to 30% by mass, more preferably 5 to 20% by mass. In addition, in order to prevent the hydrolysis of tetracarboxylic acid diester dichloride, the solvent used in the synthesis of polyamic acid ester is preferably dehydrated as much as possible, preferably in a nitrogen environment, to prevent the mixing of external air.

[0133] (3) Synthesis from tetracarboxylic acid diester and diamine

[0134] Polyamic acid ester can be synthesized by polycondensing a tetracarboxylic acid diester and a diamine.

[0135] Specifically, it can be synthesized by reacting a tetracarboxylic acid diester with a diamine in the presence of a condensing agent, a base and an organic solvent at 0 to 150° C., preferably 0 to 100° C., for 30 minutes to 24 hours, preferably 3 to 15 hours.

[0136] As the condensing agent, known compounds such as triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N,N′-carbonyldiimidazole, and dimethoxy-1,3,5-triazinylmethylmorpholinium can be used.

[0137] As the above-mentioned base, a tertiary amine such as pyridine can be used.

[0138] In order to obtain high molecular weight polyamic acid ester among the above three synthesis methods of polyamic acid ester, the synthesis method of (1) or (2) is particularly preferred.

[0139] <Production method of polyimide>

[0140] The polyimide used in the present invention can be manufactured by imidizing the above-mentioned polyamic acid ester or polyamic acid. In the case of manufacturing polyimide from polyamic acid ester, chemical imidization in which a basic catalyst is added to the above-mentioned polyamic acid ester solution or to a polyamic acid solution obtained by dissolving polyamic acid ester resin powder in an organic solvent is simple. Chemical imidization carries out imidization reaction at a relatively low temperature, and it is not easy to produce a decrease in the molecular weight of the polymer during imidization, so it is preferred.

[0141] Chemical imidization can be carried out by stirring the polyamic acid ester to be imidized in an organic solvent in the presence of a basic catalyst. As the organic solvent, the above-mentioned solvent used in the polymerization reaction can be used. As the basic catalyst, pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, etc. can be listed. Among them, triethylamine has sufficient alkalinity to allow the reaction to proceed, so it is preferred.

[0142] The temperature during the imidization reaction is -20 to 140°C, preferably 0 to 100°C, and the reaction time can be carried out for 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 molar times of the amic acid ester group, preferably 2 to 20 molar times. The imidization rate of the obtained polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time. The added catalyst remains in the solution after the imidization reaction, so it is preferred to recover the obtained imidized polymer by the method described below, and redissolve it in an organic solvent to prepare the liquid crystal alignment agent of the present invention.

[0143] In the case of preparing polyimide from polyamic acid, chemical imidization in which a catalyst is added to a solution of the polyamic acid obtained by the reaction of a diamine component with tetracarboxylic dianhydride is simple. Chemical imidization is preferred because it carries out the imidization reaction at a relatively low temperature and the molecular weight of the polymer is not easily reduced during the imidization process.

[0144] Chemical imidization can be carried out by stirring the polymer to be imidized in an organic solvent in the presence of a basic catalyst and an acid anhydride. As the organic solvent, the solvent used in the polymerization reaction mentioned above can be used. As the basic catalyst, pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine, etc. can be listed. Among them, pyridine has a moderate alkalinity that allows the reaction to proceed, so it is preferred. In addition, as anhydrides, acetic anhydride, trimellitic anhydride, pyromellitic anhydride, etc. can be listed. Among them, if acetic anhydride is used, purification after the reaction is completed becomes easy, so it is preferred.

[0145] The temperature during the imidization reaction is -20 to 140°C, preferably 0 to 100°C, and the reaction time can be 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 times by mole of the amic acid group, preferably 2 to 20 times by mole, and the amount of the acid anhydride is 1 to 50 times by mole of the amic acid group, preferably 3 to 30 times by mole. The imidization rate of the obtained polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time.

[0146] Since the added catalyst and the like remain in the solution after the imidization reaction of the polyamic acid ester or the polyamic acid, it is preferable to recover the obtained imidized polymer by the method described below, and to redissolve it in an organic solvent to obtain the liquid crystal aligning agent of the present invention.

[0147] The polyimide solution obtained as described above is poured into a poor solvent while being fully stirred to precipitate a polymer. The precipitation is performed several times, and after washing with a poor solvent, it is dried at room temperature or by heating to obtain a purified polyimide powder.

[0148] The poor solvent is not particularly limited, and examples thereof include methanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, and benzene.

[0149] <Method for producing terminally modified polymer (A)>

[0150] A polymer (A) having a group represented by the above formula (6) at the end can be obtained, for example, by the following method: when at least one tetracarboxylic acid derivative selected from the group consisting of tetracarboxylic dianhydride, tetracarboxylic diester dichloride and tetracarboxylic diester is reacted with a diamine to produce the above polymer (A), a terminal modifier such as a carbonate, a monocarbonyl chloride, or an acid anhydride, a monoamine having a group "*-CO-O-Z" (Z is synonymous with Z in the above formula (6). * represents a bonding bond) is allowed to exist and react.

[0151] Preferred specific examples of the terminal modification agent include compounds represented by the following formula (R-1) or (R-2), monoamines having a group represented by the above formula (6), etc. The terminal modification agent may be used alone or in combination of two or more.

[0152]

[0153] In the formula (R-1) and (R-2), R 22 , R 22' represents a monovalent organic group. Specific examples thereof include methyl, ethyl, propyl, 2,2,2-trichloroethyl, 2-trimethylsilylethyl, 1,1-dimethylpropynyl, 1-methyl-1-phenylethyl, 1-methyl-1-(4-biphenylyl)ethyl, 1,1-dimethyl-2-haloethyl, 1,1-dimethyl-2-cyanoethyl, tert-butyl, cyclobutyl, 1-methylcyclobutyl, 1-adamantyl, vinyl, allyl, cinnamyl, 8-quinolyl, N-hydroxypiperidinyl, benzyl, p-nitrobenzyl, 3,4-dimethoxy-6-nitrobenzyl, 2,4-dichlorobenzyl, 9-fluorenylmethyl, and the like.

[0154] When synthesizing a polymer (A) having a group represented by the above formula (6) at a terminal, the amount of the terminal modifier used is preferably 20 parts by mole or less, more preferably 0.001 to 10 parts by mole, based on 100 parts by mole of the total diamine used to produce the polymer (A).

[0155] <Liquid crystal alignment agent>

[0156] The liquid crystal aligning agent of the present invention contains a polymer (A) as the (A) component and a polymer (B) as the (B) component. In addition to the polymer (A) and the polymer (B), the liquid crystal aligning agent of the present invention may also contain other polymers. As other polymers, polyamic acid, polyimide, polyamic acid ester, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivatives, polyacetal, polystyrene or its derivatives, poly (styrene-phenylmaleimide) derivatives, poly (meth) acrylates, etc. can be listed.

[0157] The liquid crystal alignment agent is used to make a liquid crystal alignment film, and from the viewpoint of forming a uniform film, it takes the form of a coating liquid. In the liquid crystal alignment agent of the present invention, a coating liquid containing the above-mentioned polymer component and an organic solvent is also preferred. At this time, the content (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. From the perspective of forming a uniform and defect-free coating film, the concentration of the polymer is preferably 1% by mass or more, and from the perspective of the storage stability of the solution, the concentration of the polymer is preferably 10% by mass or less. The concentration of the polymer is particularly preferably 2 to 8% by mass.

[0158] The organic solvent contained in the liquid crystal alignment agent is not particularly limited as long as it uniformly dissolves the polymer component. If specific examples are given, they 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-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide (collectively referred to as good solvents), etc. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N, N-dimethylpropaneamide, 3-butoxy-N, N-dimethylpropaneamide or γ-butyrolactone is preferably used. The good solvent is preferably 20 to 99% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass.

[0159] In addition, the organic solvent contained in the liquid crystal aligning agent is preferably a mixed solvent of a solvent (also called a poor solvent) that improves the coating property and surface smoothness of the coating film when the liquid crystal aligning agent is applied, in addition to the solvents described above. Specific examples of the poor solvents used are listed below, but are not limited to these examples.

[0160] For example, diisopropyl ether, diisobutyl ether, diisobutyl carbinol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 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 monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol, 2-( 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, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isopentyl lactate, diethylene glycol monoethyl ether, diisobutyl ketone (2,6-dimethyl-4-heptanone), etc.

[0161] As the poor solvent, 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 are preferred. The poor solvent is preferably 1 to 80% by mass of the total solvent contained in the liquid crystal aligning agent, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass. 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.

[0162] Preferred combinations of 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-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether; 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-methyl-2-pyrrolidone, γ-butyrolactone, ethylene glycol monobutyl ether and dipropylene glycol monomethyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone and ethylene glycol monobutyl ether monoacetate; N-methyl-2-pyrrolidone, γ-butyrolactone, ethylene glycol monobutyl ether monoacetate and dipropylene glycol monomethyl ether, etc.

[0163] The liquid crystal aligning agent of the present invention may also contain additional components other than the polymer component and the organic solvent. Such additional components include: a close adhesion aid for improving the close adhesion between the liquid crystal aligning film and the substrate, and the close adhesion between the liquid crystal aligning film and the sealant; a compound for improving the strength of the liquid crystal aligning film (hereinafter, also referred to as a cross-linking compound); a dielectric for adjusting the dielectric constant and resistance of the liquid crystal aligning film, a conductive material, etc.

[0164] As the above-mentioned cross-linking compound, from the viewpoint of less generation of AC afterimages and high improvement effect of film strength, it is preferably selected from the group consisting of the following compounds: a compound having at least one group selected from the group consisting of an oxirane group, an oxetane group, a protected isocyanate group, a protected isothiocyanate group, a group containing an oxazoline ring structure, a group containing a Michaelis acid structure, a cyclocarbonate group as shown below and a group represented by formula (d); and a compound represented by the following formula (e) (hereinafter collectively referred to as compound (C)).

[0165]

[0166] (R 32 and R 33 Each of them is independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or "*-CH2-OH". * represents a bond. A represents an organic group having an aromatic ring and having a valence of (m+n). m represents an integer of 1 to 6, and n represents an integer of 0 to 4.)

[0167] Specific examples of compounds having an oxirane group include, for example, compounds described in paragraph

[0037] of Japanese Patent Application Laid-Open No. 10-338880, compounds having a triazine ring described in WO2017 / 170483, and compounds having two or more oxirane groups. Among them, N,N,N',N'-tetraglycidyl-m-xylene diamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetraglycidyl-p-phenylenediamine, and compounds of the following formulas (r-1) to (r-3) that contain nitrogen atoms are particularly preferred.

[0168]

[0169] Specific examples of the compound having an oxetane group include compounds having two or more oxetane groups described in paragraphs

[0170] to

[0175] of WO2011 / 132751.

[0170] Specific examples of compounds having protected isocyanate groups include, for example, compounds having two or more protected isocyanate groups described in paragraphs

[0046] to

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

[0119] to

[0120] of WO2015 / 141598, etc. Among them, compounds represented by any of the following formulas (bi-1) to (bi-3) are preferred.

[0171]

[0172] Specific examples of the compound having a protected isothiocyanate group include compounds having two or more protected isothiocyanate groups described in JP-A-2016-200798.

[0173] Specific examples of the compound having a group containing an oxazoline ring structure include compounds containing two or more oxazoline structures described in paragraph

[0115] of JP-A-2007-286597.

[0174] Specific examples of the compound having a group containing a Michaelis acid structure include compounds having two or more Michaelis acid structures described in WO2012 / 091088.

[0175] Specific examples of the compound having a cyclic carbonate group include compounds described in WO2011 / 155577.

[0176] R as the group represented by the above formula (d) 32 , R 33 Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group.

[0177] Specific examples of the compound having a group represented by the above formula (d) include, for example, compounds having two or more groups represented by the above formula (d) described in paragraph

[0058] of WO2015 / 072554 and JP-A-2016-118753; compounds described in JP-A-2016-200798, etc. Among them, compounds represented by any of the following formulas (hd-1) to (hd-8) are preferred.

[0178]

[0179] Examples of the (m+n)-valent organic group having an aromatic ring in A of the above formula (e) include: an (m+n)-valent aromatic hydrocarbon group having 6 to 30 carbon atoms, an (m+n)-valent organic group formed by directly or via a linking group bonding an aromatic hydrocarbon group having 6 to 30 carbon atoms, and an (m+n)-valent group having an aromatic heterocyclic ring. Examples of the above aromatic hydrocarbon group include: benzene, naphthalene, etc.

[0180] Examples of the aromatic heterocyclic ring include a pyrrole ring, an imidazole ring, a pyrazole ring, a pyridine ring, a pyrimidine ring, a quinoline ring, an isoquinoline ring, a carbazole ring, a pyridazine ring, a pyrazine ring, a benzimidazole ring, an indole ring, a quinoxaline ring, and an acridine ring.

[0181] As the above-mentioned linking group, there can be listed: an alkylene group having 1 to 10 carbon atoms, or a group in which one hydrogen atom is removed from the above-mentioned alkylene group, a divalent or trivalent cyclohexane ring, etc. It should be noted that any hydrogen atom of the above-mentioned alkylene group is optionally substituted by an organic group such as a fluorine atom or a trifluoromethyl group. If specific examples are listed, the compounds described in WO2010 / 074269 can be listed. As preferred specific examples, compounds of any formula in the following formulas (e-1) to (e-9) can be listed.

[0182]

[0183] The above compound is an example of a crosslinking compound, but is not limited thereto. For example, components other than those disclosed in paragraphs

[0105] to

[0116] of WO2015 / 060357 can be cited. In addition, the crosslinking compound contained in the liquid crystal aligning agent of the present invention may be one kind or a combination of two or more kinds.

[0184] The content of the crosslinkable compound in the liquid crystal aligning agent of the present invention is preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent, and is more preferably 1 to 15 parts by mass from the viewpoint that the crosslinking reaction proceeds, the target effect is achieved, and AC residual image characteristics are small.

[0185] Examples of the adhesion aid include 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, and N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane. Ethoxycarbonyl-3-aminopropyl triethoxysilane, N-triethoxysilylpropyl triethylenetriamine, N-trimethoxysilylpropyl triethylenetriamine, 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-aminopropyl trimethoxysilane, N-benzyl-3-aminopropyl triethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis(oxyethylene)-3-aminopropyltrimethoxysilane, N-bis(oxyethylene)-3-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyl Silane coupling agents such as oxypropyl triethoxysilane, p-phenylvinyl trimethoxysilane, 3-methacryloxypropyl methyl dimethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-methacryloxypropyl methyl diethoxysilane, 3-methacryloxypropyl triethoxysilane, 3-acryloxypropyl trimethoxysilane, tris-(trimethoxysilylpropyl) isocyanurate, 3-mercaptopropyl methyl dimethoxysilane, 3-mercaptopropyl trimethoxysilane, and 3-isocyanate propyl triethoxysilane. When using a silane coupling agent, from the viewpoint of less AC residual image, the amount is preferably 0.1 to 30 parts by mass, and 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.

[0186] <Liquid crystal alignment film / liquid crystal display element>

[0187] The liquid crystal alignment film is a film obtained by applying the above-mentioned liquid crystal alignment agent to a substrate, drying and firing. As a substrate for applying the liquid crystal alignment agent of the present invention, there is no particular limitation as long as it is a substrate with high transparency, and a glass substrate, a silicon nitride substrate, and a plastic substrate such as an acrylic substrate, a polycarbonate substrate, etc. can be used. At this time, if a substrate having an ITO electrode or the like for driving a liquid crystal is used, it is preferred from the perspective of process simplification. 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 the electrode in this case can also use a material that reflects light such as aluminum.

[0188] The coating method of the liquid crystal alignment agent on the substrate is not particularly limited, and is generally performed by screen printing, offset printing, flexographic printing or inkjet method in industry. Other coating methods include dipping, roll coating, slit coating, spin coating or spray coating, and they can be used according to the purpose.

[0189] After the liquid crystal alignment agent is applied to the substrate, the solvent can be evaporated by a heating unit such as a heating plate, a heat circulation oven or an IR (infrared) oven to form a liquid crystal alignment film. The drying and firing processes after the liquid crystal alignment agent is applied can select any temperature and time. Usually, in order to fully remove the contained solvent, the conditions of firing at 50 to 120°C for 1 to 10 minutes and then firing at 150 to 300°C for 5 to 120 minutes can be listed. If the thickness of the liquid crystal alignment film after firing is too thin, the reliability of the liquid crystal display element will sometimes be reduced, so it is preferably 5 to 300nm, and more preferably 10 to 200nm.

[0190] The method of performing an alignment treatment on the liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention may be a brushing treatment method, or a photo-alignment treatment method may be used.

[0191] In the orientation treatment utilizing brushing or photo-orientation, in order to improve the orientation of the liquid crystal, it is preferred, depending on the circumstances, to carry out the orientation treatment after heating at a temperature of 150 to 250°C. Alternatively, the substrate coated with a liquid crystal orientation film may be heated at 50 to 250°C while being oriented.

[0192] Furthermore, in the above-mentioned method, the liquid crystal alignment film after the alignment treatment may be subjected to contact treatment using water or a solvent to remove impurities attached to the liquid crystal alignment film.

[0193] The solvent used in the contact treatment is not particularly limited, and specific examples thereof 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, and cyclohexyl acetate.

[0194] The liquid crystal alignment film of the present invention is preferably used as a liquid crystal alignment film of a liquid crystal display element of a transverse electric field mode such as an IPS mode and an FFS mode, and is particularly useful as a liquid crystal alignment film of an entire liquid crystal display element of the FFS mode. The liquid crystal display element is obtained by preparing a liquid crystal cell by a known method after obtaining a substrate with a liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention, and using the liquid crystal cell.

[0195] As an example of a method for manufacturing a liquid crystal cell, a passive matrix liquid crystal display element is used as an example. It should be noted that an active matrix liquid crystal display element in which a conversion element such as a TFT (Thin Film Transistor) is provided in each pixel portion constituting an image display may also be used.

[0196] Specifically, a transparent glass substrate is prepared, a common electrode is provided on one substrate, and a segmented electrode is provided on the other substrate. These electrodes can be, for example, ITO electrodes, and patterned in a manner that can display a desired image. Next, an insulating film is provided on each substrate in a manner that covers the common electrode and the segmented electrode. The insulating film can be, for example, a SiO2-TiO2 film formed by a sol-gel method.

[0197] Next, a liquid crystal alignment film is formed on each substrate, and the substrate of one side is superimposed with the substrate of the other side in a manner that the liquid crystal alignment film faces face each other, and the periphery is bonded by a sealant. In order to control the gap between the substrates, spacers are usually mixed into the sealant. In addition, it is preferred to pre-spread spacers for controlling the gap between the substrates in the surface where the sealant is not provided. In a part of the sealant, an opening that can be filled with liquid crystal from the outside is pre-set. Next, through the opening provided in the sealant, liquid crystal material is injected into the space surrounded by the two substrates and the sealant, and then the opening is sealed with an adhesive. The injection can be performed by a vacuum injection method or by a method that utilizes capillary phenomena in the atmosphere. The liquid crystal material can use any one of a positive liquid crystal material and a negative liquid crystal material, preferably a negative liquid crystal material. Next, a polarizing plate is set. Specifically, a pair of polarizing plates are bonded to the surface of the two substrates on the opposite side of the liquid crystal layer.

[0198] Example

[0199] The following examples are given to further illustrate the present invention, but the present invention is not limited thereto. The abbreviations of the following compounds and the methods for measuring the properties are as follows. In addition, "%" means "mass %" unless otherwise specified.

[0200] (Diamine)

[0201] l-1: A compound represented by the following formula (l-1).

[0202] m-1: a compound represented by the following formula (m-1).

[0203] n-1: a compound represented by the following formula (n-1).

[0204] DA-1 to DA-7: compounds represented by the following formulae (DA-1) to (DA-7), respectively.

[0205] (Tetracarboxylic dianhydride)

[0206] CA-1 to CA-4: compounds represented by the following formulae (CA-1) to (CA-4), respectively.

[0207] (Compound C)

[0208] C-1: A compound represented by the following formula (C-1).

[0209] (Compound D)

[0210] D-1: A compound represented by the following formula (D-1).

[0211] (Compound E)

[0212] E-1: A compound represented by the following formula (E-1).

[0213] (Organic Solvent)

[0214] NMP: N-methyl-2-pyrrolidone, GBL: γ-butyrolactone.

[0215] BCS: Butyl Cellosolve.

[0216]

[0217]

[0218] (Et represents ethyl.)

[0219] <Measurement of Imidization Ratio>

[0220] Add polyimide powder (20 mg) to an NMR sample tube (NMR standard sampling tube, φ5 (manufactured by Kusano Scientific Co., Ltd.)), add deuterated dimethyl sulfoxide (DMSO-d6, 0.05% TMS (tetramethylsilane) mixture) (0.53 ml), and apply ultrasound to completely dissolve it. The solution was measured by 500 MHz proton NMR in an NMR measuring machine (JNW-ECA500, manufactured by JEOL DATUM Co., Ltd.). The imidization rate was calculated as follows: the proton derived from the structure that does not change before and after imidization is determined as the reference proton, and the peak integral value of the proton derived from the NH group of the amic acid appearing near 9.5 ppm to 10.0 ppm is used to calculate it using the following formula.

[0221] Imidization rate (%) = (1-α·x / y) × 100

[0222] In the above formula, x is the peak integral value of protons derived from NH groups of amic acid, y is the peak integral value of reference protons, and α is the ratio of the number of reference protons to protons of one NH group of amic acid in the case of polyamic acid (imidation ratio 0%).

[0223] [Synthesis of polymer]

[0224] <Synthesis example 1>

[0225] DA-2 (8.60 g, 35.2 mmol), DA-4 (5.34 g, 9.59 mmol) and DA-3 (7.65 g, 19.1 mmol) were weighed into a 1L four-necked flask equipped with a stirring device and a nitrogen inlet tube, and NMP was added so that the solid content concentration was 12%, and the mixture was stirred and dissolved while nitrogen was supplied. CA-1 (9.32 g, 41.6 mmol) was added while stirring the diamine solution under water cooling, and NMP was further added so that the solid content concentration was 15%, and the mixture was stirred at 40°C for 3 hours under a nitrogen environment. Furthermore, CA-2 (2.82 g, 14.3 mmol) was added, and NMP was further added so that the solid content concentration was 15%, and the mixture was stirred at 23°C for 4 hours under a nitrogen environment to obtain a polyamic acid solution.

[0226] The polyamic acid solution (80.0 g) obtained above was taken into a 3L conical flask with a stirrer, and NMP (70.0 g), acetic anhydride (6.97 g) and pyridine (1.80 g) were added. After stirring at room temperature for 30 minutes, the mixture was reacted at 55° C. for 3 hours. The reaction solution was put into 560 g of methanol, and the obtained precipitate was filtered out. After the precipitate was washed with methanol, it was dried under reduced pressure at 60° C. to obtain a polyimide powder (imidization rate: 75%).

[0227] Polyimide powder (9.00 g) was taken out into a 300 mL Erlenmeyer flask containing a stirrer, NMP (36.0 g) was added, and the mixture was stirred at 50° C. for 20 hours to dissolve the mixture, thereby obtaining a polyimide (PI-A-1) solution having a solid content concentration of 20%.

[0228] <Synthesis example 2>

[0229] The diamine, tetracarboxylic acid derivative and organic solvent shown in Table 1 below were used, and the same order as in Synthesis Example 1 was used to implement the polyamic acid of the composition shown in Table 1 below. The obtained polyamic acid solution (1000.0 g) was taken, and compound E-1 (45.32 g, 207.63 mmol) was added. After further stirring for 12 hours, NMP, acetic anhydride and pyridine were used in the same manner as in Synthesis Example 1 to obtain a solution of polyimide (PI-A-2). In Table 1, for the numerical values ​​in brackets, for the tetracarboxylic acid component, the mixing ratio (mol parts) of each compound relative to 100 mol parts of the total amount of the diamines used for synthesis is indicated, and for the diamine component, the mixing ratio (mol parts) of each compound relative to 100 mol parts of the total amount of the diamines used for synthesis is indicated. For the organic solvent, the mixing ratio (mass parts) of each organic solvent relative to 100 mass parts of the total amount of the organic solvents used for synthesis is indicated.

[0230] <Synthesis Example 3>

[0231] l-1 (12.00 g, 111.0 mmol), m-1 (29.34 g, 148.0 mmol) and n-1 (46.79 g, 111.0 mmol) were measured in a 1L four-necked flask equipped with a stirring device and a nitrogen inlet tube, and NMP (451.7 g) and GBL (194.7 g) were added so that the solid content concentration became 12%, and stirred to dissolve while nitrogen was supplied. While stirring the diamine solution under water cooling, CA-2 (55.14 g, 281.1 mmol) and GBL were added so that the solid content concentration became 14.5%, and stirred for 2 hours under water cooling in a nitrogen atmosphere. CA-3 (16.14 g, 74.0 mmol) was then added, and GBL was added to give a solid content concentration of 15%. The mixture was stirred at 50° C. for 15 hours under a nitrogen atmosphere to obtain a polyamic acid (PAA-B-1) solution having a solid content of 15% and NMP / GBL=50 / 50.

[0232] <Synthesis Example 4>

[0233] l-1 (12.00 g, 111.0 mmol), m-1 (29.34 g, 148.0 mmol) and n-1 (46.79 g, 111.0 mmol) were measured in a 1L four-necked flask equipped with a stirring device and a nitrogen inlet tube, and NMP (447.1 g) and GBL (199.3 g) were added so that the solid content concentration became 12%, and stirred to dissolve while nitrogen was supplied. While stirring the diamine solution under water cooling, CA-2 (69.65 g, 355.2 mmol) and GBL were added so that the solid content concentration became 15.0%, and stirred for 5 hours under water cooling under a nitrogen atmosphere to obtain a polyamic acid (PAA-B-2) solution with a solid content of 15% and NMP / GBL = 50 / 50.

[0234] <Synthesis Examples 5 to 9>

[0235] The diamines, tetracarboxylic acid derivatives and organic solvents shown in Table 1 below were used and the same order as in Synthesis Example 3 was followed to obtain solutions of polyamic acids (PAA-B-3) to (PAA-B-7) shown in Table 1 below. In Table 1, the numerical values ​​in parentheses indicate the mixing ratio (mol parts) of each compound relative to 100 mol parts of the total amount of diamines used for synthesis for the tetracarboxylic acid component, and the mixing ratio (mol parts) of each compound relative to 100 mol parts of the total amount of diamines used for synthesis for the diamine component. For the organic solvent, the mixing ratio (mass parts) of each organic solvent relative to 100 parts by mass of the total amount of organic solvents used for synthesis is indicated.

[0236] <Synthesis Example 10>

[0237] The diamines, tetracarboxylic acid derivatives and organic solvents shown in Table 1 below were used and the same order as in Synthesis Example 4 was followed to obtain a solution of a polyamic acid (PAA-B-8) shown in Table 1 below. In Table 1, the values ​​in parentheses indicate the mixing ratio (mol parts) of each compound relative to 100 mol parts of the total amount of the diamines used for synthesis for the tetracarboxylic acid component, and the mixing ratio (mol parts) of each compound relative to 100 mol parts of the total amount of the diamines used for synthesis for the diamine component. For the organic solvent, the mixing ratio (mass parts) of each organic solvent relative to 100 parts by mass of the total amount of the organic solvents used for synthesis is indicated.

[0238] [Table 1]

[0239]

[0240] <Example 1>

[0241] [Preparation of Liquid Crystal Alignment Agent]

[0242] The solution of the polyimide (PI-A-2) obtained in Synthesis Example 2 and the solution of the polyamic acid (PAA-B-1) obtained in Synthesis Example 3 were diluted with NMP, GBL and BCS, and the compound (C-1) was further added so that the amount of the compound (C-1) was 3 parts by mass relative to 100 parts by mass of all polymers. 1 part by mass of the compound (D-1) was added relative to a total of 100 parts by mass of all polymers, and the mixture was stirred at room temperature. Next, the obtained solution was filtered using a filter having a pore size of 0.5 μm, thereby obtaining a liquid crystal aligning agent (1) (see Table 2 below), wherein the polymer component ratio is (PI-A-2): (PAA-B-1) = 40: 60 (solid content conversion mass ratio), the solvent composition ratio is solid content: NMP: GBL: BCS = 4.5: 30: 45.5: 20 (mass ratio), and the compound (C-1) and the compound (D-1) are respectively 3 parts by mass and 1 part by mass relative to a total of 100 parts by mass of the polymer component. No abnormalities such as turbidity and precipitation were observed in the liquid crystal aligning agent, and it was confirmed to be a uniform solution.

[0243] <Examples 2 to 8, Comparative Examples 1 to 4>

[0244] Except for the polymer and polymerization ratio shown in Table 2 below, the same method as in Example 1 was used to obtain liquid crystal aligning agents (2) to (12). In Table 2, for the values ​​in brackets, for polymers and compounds (C), the proportions (parts by mass) of each polymer component or compound (C) relative to a total of 100 parts by mass of the polymer components used to prepare the liquid crystal aligning agent are represented. For organic solvents, the proportions (parts by mass) of each organic solvent relative to a total of 100 parts by mass of the organic solvents contained in the liquid crystal aligning agent are represented.

[0245] [Table 2]

[0246]

[0247] [Fabrication of FFS-type liquid crystal display element]

[0248] A liquid crystal cell having a structure of a fringe field switching (FFS) mode liquid crystal display element was produced.

[0249] First, a substrate with electrodes was prepared. The substrate was a glass substrate with a size of 30 mm × 35 mm and a thickness of 0.7 mm. On the substrate, as the first layer, an ITO electrode with a closely packed pattern constituting a counter electrode was formed. On the counter electrode of the first layer, as the second layer, a SiN (silicon nitride) film formed by CVD (chemical vapor deposition) was formed. The thickness of the second layer of SiN film was 500 nm, and it functions as an interlayer insulating film. On the second layer of SiN film, as the third layer, a comb-shaped pixel electrode formed by patterning the ITO film was arranged, forming two types of pixels, the first pixel and the second pixel. The size of each pixel is 10 mm long and about 5 mm wide. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated due to the action of the SiN film of the second layer.

[0250] The pixel electrode of the third layer has a comb-like shape formed by arranging a plurality of electrode elements in the shape of a "< symbol" with a bent central portion. The width of each electrode element in the short dimension direction is 3μm, and the interval between the electrode elements is 6μm. The pixel electrode forming each pixel is composed of a plurality of electrode elements in the shape of a "< symbol" with a bent central portion, so the shape of each pixel is not a rectangle, but a shape similar to a bold "< symbol" that is bent in the central portion like the electrode elements. In addition, each pixel is divided into upper and lower parts with the bent portion in the center as the boundary, and has a first area on the upper side of the bent portion and a second area on the lower side.

[0251] Comparing the first area and the second area of ​​each pixel, the formation direction of the electrode elements constituting their pixel electrodes is different. That is, with the brushing direction of the liquid crystal alignment film described later as a reference, in the first area of ​​the pixel, the electrode elements of the pixel electrode are formed in a manner to become an angle of +10° (clockwise), and in the second area of ​​the pixel, the electrode elements of the pixel electrode are formed in a manner to become an angle of -10° (clockwise). That is, in the first area and the second area of ​​each pixel, the directions of the rotational movement (in-plane / switching) of the liquid crystal within the substrate surface induced by the voltage application between the pixel electrode and the opposing electrode are configured to be opposite to each other.

[0252] Next, after filtering the liquid crystal alignment agent with a 1.0 μm filter, it was applied by spin coating on the prepared substrate with electrodes and a glass substrate with a columnar spacer with a height of 4 μm and an ITO film formed on the back. After drying on a hot plate at 80°C for 5 minutes, it was sintered in a hot air circulation oven at 230°C for 20 minutes to obtain a polyimide film with a film thickness of 60 nm. The polyimide film was brushed with rayon cloth (roller diameter: 120 mm, roller speed: 500 rpm, moving speed: 30 mm / sec, pressing length: 0.3 mm, brushing direction: 10° tilted relative to the third layer of IZO comb electrode), and then irradiated with ultrasonic waves in pure water for 1 minute for cleaning, and water droplets were removed by air blowing. Then, it was dried at 80°C for 15 minutes to obtain a substrate with a liquid crystal alignment film. The two substrates with liquid crystal alignment films were grouped together, and the sealant was printed in the form of a liquid crystal injection port remaining on the substrate. The other substrate was bonded in a manner that the liquid crystal alignment film surface faced each other and the brushing direction became reversely parallel. Then, the sealant was cured to produce an empty box with a cell gap of 4μm. Negative liquid crystal MLC-7026-100 (manufactured by MERCK) was injected into the empty box by the reduced pressure injection method, and the injection port was sealed to obtain an FFS liquid crystal box. Then, the obtained liquid crystal box was heated at 120°C for 1 hour, left at 23°C overnight, and used for the evaluation of liquid crystal orientation.

[0253] [Preparation of Liquid Crystal Cell for Voltage Holding Ratio Measurement]

[0254] After filtering the liquid crystal alignment agent with a filter with a pore size of 1.0 μm, it was applied to a substrate with an electrode (a glass substrate with a size of 30 mm long × 40 mm wide and a thickness of 1.1 mm. The electrode is an ITO electrode with a rectangular size of 10 mm wide × 40 mm long and a thickness of 35 nm) by spin coating. After drying on a hot plate at 50°C for 5 minutes, it was calcined in an IR oven at 230°C for 20 minutes to form a coating with a film thickness of 60 nm to obtain a substrate with a liquid crystal alignment film. The liquid crystal alignment film was brushed with rayon cloth (YA-20R made by Yoshikawa Chemical Industry) (roller diameter: 120 mm, roller rotation speed: 1000 rpm, moving speed: 30 mm / sec, pressing length: 0.3 mm), and then irradiated with ultrasonic waves in pure water for 1 minute for cleaning. After removing water droplets by blowing, it was dried at 80°C for 15 minutes to obtain a substrate with a liquid crystal alignment film.

[0255] Prepare two substrates with liquid crystal alignment films as described above, spread spacers with a height of 4 μm on the surface of one liquid crystal alignment film, print a sealant from above, and bond the other substrate in the opposite direction of the brushing direction and with the film surfaces facing each other, and then cure the sealant to make an empty box. Inject negative liquid crystal MLC-7026-100 (made by MERCK) into the empty box by the reduced pressure injection method, seal the injection port, and obtain a liquid crystal box. Then, heat the obtained liquid crystal box at 120°C for 1 hour and leave it at 23°C overnight to obtain a liquid crystal box for voltage retention measurement.

[0256] [Preparation of Transmittance Evaluation Substrate]

[0257] After filtering the obtained liquid crystal alignment agent with a filter having a pore size of 1.0 μm, the alignment agent was spin-coated on a quartz substrate, dried on a hot plate at 80°C for 2 minutes, and then calcined at 230°C for 20 minutes to form a polyimide film with a thickness of 100 nm. Double-sided tape was applied only to the two sides facing the coating surface of the substrate, and the film was bonded to a quartz substrate without any film formation. The substrate formed by injecting benzyl benzoate into the simple box thus prepared was used as an evaluation substrate.

[0258] [evaluate]

[0259] 1. Image retention evaluation based on long-term AC drive

[0260] A liquid crystal cell having the same structure as that used in the above-mentioned afterimage evaluation was prepared.

[0261] Using this liquid crystal cell, an AC voltage of ±5 V with a frequency of 60 Hz was applied for 120 hours in a constant temperature environment of 60° C. Then, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited and left at room temperature for one day.

[0262] After placement, the liquid crystal box is placed between two polarizing plates arranged in a manner such that the polarization axes are orthogonal, the backlight is turned on without applying voltage, and the configuration angle of the liquid crystal box is adjusted to minimize the brightness of the transmitted light. Then, the rotation angle when the liquid crystal box is rotated from the angle at which the second area of ​​the first pixel becomes the darkest to the angle at which the first area becomes the darkest is calculated as angle Δ. Similarly, for the second pixel, the second area is compared with the first area, and the same angle Δ is calculated.

[0263] When the angle Δ is less than 0.13°, the liquid crystal orientation is favorable.

[0264] 2. Determination of the relaxation rate of accumulated charge

[0265] The liquid crystal box produced in the same manner as above (production of liquid crystal box) was placed between two polarizing plates arranged in an orthogonal manner, and the LED backlight was irradiated from below the two polarizing plates while the pixel electrode and the opposing electrode were short-circuited to be at the same potential. The angle of the liquid crystal box was adjusted so that the brightness of the LED backlight transmission light measured on the two polarizing plates was minimized. Then, while applying an AC voltage with a frequency of 60 Hz to the liquid crystal box, the V-T curve (voltage-transmittance curve) was measured, and the AC voltage at which the relative transmittance became 23% was calculated as the driving voltage.

[0266] In the afterimage evaluation, the liquid crystal cell was driven for 120 minutes while applying an AC voltage of 60 Hz at a relative transmittance of 23% and simultaneously applying a DC voltage of 1 V. Then, the DC voltage was stopped and the liquid crystal cell was driven for another 15 minutes only with the AC voltage.

[0267] The case where the relative transmittance relaxed to 25% or less within 10 minutes from the time when the DC voltage application was stopped was evaluated as "good", and the case where it took more than 10 minutes for the relative transmittance to drop to 25% or less was evaluated as "poor".

[0268] Furthermore, the afterimage evaluation according to the above method was performed under the temperature condition that the temperature of the liquid crystal cell was 40°C.

[0269] 3. Black level evaluation

[0270] The liquid crystal box produced in the same manner as above (production of liquid crystal box) was placed between two polarizing plates arranged in a manner that the polarization axes were orthogonal to each other. The backlight was turned on without applying voltage, and the configuration angle of the liquid crystal box was adjusted to minimize the brightness of the transmitted light. The liquid crystal box was observed using a digital CCD camera "C8800-21C" manufactured by Hamamatsu Photonics, and the brightness of the captured image was quantified using the company's analysis software "ExDcam Image capture Software". If the brightness value of the liquid crystal box is 580 or less, it is considered "good", and if it is above, it is considered "bad".

[0271] 4. Evaluation of voltage holding ratio and backlight tolerance

[0272] A voltage of 1 V was applied to the voltage holding ratio measurement liquid crystal cell at a temperature of 60° C. for 60 μsec, and the voltage was measured 167 msec later. The voltage holding ratio was calculated based on how much voltage was retained. This was taken as the initial voltage holding ratio.

[0273] Next, as a backlight tolerance test, the liquid crystal cell was placed under a high-brightness backlight (20,000 cd) at a surface temperature of 50° C. for 168 hours. The voltage holding ratio of the liquid crystal cell was measured in the same manner as above, and this was taken as the voltage holding ratio after the tolerance test.

[0274] Regarding the backlight tolerance of the voltage holding ratio, a value obtained by subtracting the value after the tolerance test from the initial value was rated as “good” if less than 1%, and was rated as “poor” if greater than 1%.

[0275] 5. Evaluation of reprocessability

[0276] The liquid crystal alignment agent of the present invention is applied to the ITO substrate by spin coating. After drying on a heating plate at 60°C for 1 minute and 30 seconds, it is fired in a hot air circulation oven at 230°C for 20 minutes to form a coating film with a thickness of 100 nm. Then, the prepared substrate is immersed in a reprocessing agent (KPX company, KR-31) heated to 35°C for 600 seconds for development, and then washed in ultrapure water for 30 seconds. Then, it is dried by air blowing and the amount of residual film is observed. At this time, the case with no residual film is set as "good", and the case with residual film is set as "poor".

[0277] 6. Transmittance evaluation

[0278] The transmittance was evaluated by measuring the transmittance of the substrate obtained by the above method. Specifically, the measuring device used Cary 5000 (manufactured by VARIAN) and the transmittance was measured at a temperature of 25°C and a scanning wavelength of 380 to 800 nm. At this time, a quartz substrate not coated with any substance was used in the reference example (reference example). For evaluation, the average transmittance of the wavelength of 380 to 800 nm was calculated, and the value was set as "good" if it was 98% or more, and "bad" if it was less than 98%.

[0279] The evaluation results carried out as described above about the liquid crystal display elements using each of the liquid crystal aligning agents of Examples 1 to 8 and Comparative Examples 1 to 4 are shown in Table 3 below.

[0280] [Table 3]

[0281] Long-term AC drive Mitigation of stored charge Black level evaluation Voltage holding ratio tolerance Reprocessability Transmittance Example 1 good good good good good good Example 2 good good good good good good Example 3 good good good good good good Example 4 good good good good good good Example 5 good good good good good good Example 6 good good good good good good Example 7 good good good good good good Example 8 good good good good good good Comparative Example 1 good good good good good bad Comparative Example 2 good bad good good bad good Comparative Example 3 bad good bad bad good good Comparative Example 4 good bad good good good good

[0282] Industrial Applicability

[0283] The liquid crystal aligning agent of the present invention is useful for forming a liquid crystal aligning film in a wide range of liquid crystal display elements such as an IPS drive system and an FFS drive system.

[0284] It should be noted that the entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2019-083223 filed on April 24, 2019 are incorporated herein by reference and introduced as a disclosure of the specification of the present invention.

Claims

1. A liquid crystal alignment agent, characterized in that: Containing the following components (A) and (B), Component (A): a polymer (A) having a repeating unit represented by the following formula (1), Component (B): a polymer (B) having a repeating unit represented by the following formula (2) and a repeating unit represented by the following formula (3), In formula (1), X1 is a tetravalent organic group derived from an aromatic tetracarboxylic dianhydride or an alicyclic tetracarboxylic dianhydride, and Y1 is a divalent organic group derived from an aromatic diamine compound. In formula (2), X2 is a tetravalent organic group derived from alicyclic tetracarboxylic dianhydride or non-cyclic aliphatic tetracarboxylic dianhydride, R2 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and Z 21 , Z 22 Each independently represents a hydrogen atom or a monovalent organic group, In formula (3), X3 is a tetravalent organic group derived from alicyclic tetracarboxylic dianhydride or non-cyclic aliphatic tetracarboxylic dianhydride, Y3 is a divalent organic group selected from the group consisting of the following formulas (n-1) to (n-3), R3 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and Z 31 , Z 32 Respectively with Z in the formula (2) 21 , Z 22 Synonymous, In formulas (n-1) to (n-3), Q 2 Each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and Q 3 Each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and Q 4 Each independently represents a single bond or a structure of the following formula (Ar), n represents an integer of 1 to 3, * represents a bonding bond, In formula (Ar), Q 5 It represents a single bond, -O-, -COO-, -OCO-, -(CH2) l -, -O(CH2) m The divalent organic group in the group consisting of O-, -CONQ- and -NQCO-, k represents an integer of 1 to 5, Q represents hydrogen or a monovalent organic group, l and m represent integers of 1 to 5, *1 and *2 represent a bond, and *1 is bonded to the benzene ring of formula (n-1) to formula (n-3).

2. The liquid crystal alignment agent according to claim 1, wherein The polymer (B) further has at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (4) and a repeating unit represented by the following formula (5), Wherein, X4 and X5 are tetravalent organic groups derived from aromatic tetracarboxylic dianhydride, R4 has the same meaning as R2 in formula (2), and Z 41 , Z 42 Respectively with Z in formula (2) 21 , Z 22 Y5 is synonymous with Y3 in formula (3), R5 is synonymous with R3 in formula (3), and Z 51 , Z 52 Respectively with Z in formula (3) 31 , Z 32 Synonymous.

3. The liquid crystal aligning agent according to claim 1 or 2, wherein: The terminal of the polymer (A) has a structure represented by the following formula (6): In formula (6), * represents a bonding bond, and Z represents a monovalent organic group.

4. The liquid crystal alignment agent according to claim 3, wherein: Z in the formula (6) is selected from the group consisting of methyl, ethyl, propyl, tert-butyl, 2,2,2-trichloroethyl, 2-trimethylsilylethyl, 1,1-dimethylpropynyl, 1-methyl-1-(4-biphenylyl)ethyl, 1,1-dimethyl-2-haloethyl, 1,1-dimethyl-2-cyanoethyl, cyclobutyl, 1-methylcyclobutyl, vinyl, allyl, cinnamyl, N-hydroxypiperidinyl, benzyl and 9-fluorenylmethyl.

5. The liquid crystal aligning agent according to claim 1 or 2, wherein Y1 in the formula (1) is a divalent organic group having a partial structure represented by the following formula (H), In formula (H), R 13 is a single bond, -NRCO-, -COO-, -OCO-, -NRCONR-, -CONR- or -(CH2) n - The structure shown in the figure, the -(CH2) n -, n is an integer of 1 to 20, and when n is 2 to 20, any -CH2- is optionally substituted by -O-, -COO-, -OCO-, -ND-, -NRCO-, -CONR-, -NRCONR-, -NRCOO- or -OCOO under the condition that they are not adjacent to each other, D represents a thermally detachable group, R represents a hydrogen atom or a monovalent organic group, R 14 is a single bond or a benzene ring, any hydrogen atom on the benzene ring is optionally replaced by a monovalent organic group, *1 and *2 represent a bonding bond, and in R 14 In the case of a single bond, *2 is bonded to the nitrogen atom in the imide ring. 14 In the case of a benzene ring, R 13 is a single bond, -OCO-, -NRCONR-, or -(CH2) n - The structure shown in the figure, the -(CH2) n -, n is an integer from 1 to 20.

6. The liquid crystal aligning agent according to claim 1 or 2, wherein: Y1 in the formula (1) is a divalent organic group having a partial structure represented by any of the following formulas (H-1) to (H-14), In formulae (H-1) to (H-14), *1 and *2 represent a bond, *2 bonds to a nitrogen atom in an imide ring, and Boc represents a tert-butoxycarbonyl group.

7. The liquid crystal aligning agent according to claim 1 or 2, wherein: Y1 in the formula (1) is a divalent organic group represented by the following formula (MH-1) or (MH-2), In these, *1 is bonded to the nitrogen atom in the imide ring, and Boc represents a tert-butoxycarbonyl group.

8. The liquid crystal aligning agent according to claim 1 or 2, wherein X1 in the formula (1) is a tetravalent organic group selected from the group consisting of the following formulae (4a) to (4n), the following formula (5a) and the following formula (6a), wherein x and y are each independently a single bond, -O-, -CO-, -COO-, an alkylene group having 1 to 5 carbon atoms, 1,4-phenylene, a sulfonyl group or an amide group, and Z 1 ~Z 6 Each independently represents a hydrogen atom, a methyl group, an ethyl group, a propyl group, a chlorine atom or a benzene ring, j and k are 0 or 1, m is an integer of 1 to 5, and * represents a bond.

9. The liquid crystal alignment agent according to claim 1 or 2, wherein: The content ratio of the polymer (A) to the polymer (B) is 5 / 95 to 95 / 5 in terms of the mass ratio of polymer (A) / polymer (B).

10. The liquid crystal aligning agent according to claim 1 or 2, wherein The compound (C) is selected from the following compounds: a compound having at least one group selected from the group consisting of an oxirane group, an oxetane group, a protected isocyanate group, a protected isothiocyanate group, a group containing an oxazoline ring structure, a group containing a Michaelis acid structure, a cyclocarbonate group, and a group represented by the following formula (d); and a compound represented by the following formula (e), In formula (d), R 32 and R 33 Each is independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or "*-CH2-OH", where * represents a bond. In formula (e), A represents an (m+n)-valent organic group having an aromatic ring, m represents an integer of 1 to 6, and n represents an integer of 0 to 4.

11. The liquid crystal alignment agent according to claim 10, wherein: Content of the said compound (C) is 0.5-20 mass parts with respect to 100 mass parts of polymer components contained in the liquid crystal aligning agent. 12 . A liquid crystal alignment film obtained from the liquid crystal alignment agent according to claim 1 . 13 . A liquid crystal display element comprising the liquid crystal alignment film according to claim 12 .

14. The liquid crystal display element according to claim 13, wherein The liquid crystal display element is driven by a transverse electric field.

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