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

Abstract

The present invention provides a liquid crystal alignment agent, which can obtain a liquid crystal alignment film that has good resistance to AC afterimages or afterimages derived from residual DC and has good adhesion to a sealant, and can obtain a liquid crystal display element that suppresses the deviation of brightness within the surface during black display and has excellent contrast characteristics. The liquid crystal alignment agent 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 (3). (In formula (1), R 1 ~R 4 is a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, etc., R 1 ~R 4 At least one of Y is a group other than a hydrogen atom as defined above. 1 is a divalent organic group having a partial structure represented by the following formula (H). 3 is a tetravalent organic group derived from an aromatic dianhydride, Y 3 is a divalent organic group having a partial structure represented by formula (m). 30 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 31 , Z 32 is a hydrogen atom, etc. )(Q 3 For - (CH 2 ) n -(n is 2 to 20), any -CH 2 - is optionally substituted by -O-. The oxygen atoms are not directly bonded to each other. Any hydrogen atom on the benzene ring is optionally substituted by a monovalent organic group. * represents a 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, televisions, 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 a driving method 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 fringe field switch (hereinafter referred to as FFS: Fringe Field Switching) method.

[0003] Now, the most popular liquid crystal alignment film in industry is made by so-called brushing treatment, and the brushing treatment is to rub the surface of the film formed by polyamic acid and / or polyimide formed by imidization on the electrode substrate with cotton, nylon, polyester, etc. along one direction. Brushing treatment is a simple and productive method useful in industry. However, with the high performance, high refinement and large-scale of liquid crystal display elements, the damage, dust, mechanical force, static electricity of the surface of the alignment film produced in the brushing treatment, and then the various problems such as the unevenness in the orientation treatment surface become obvious. As a liquid crystal orientation treatment method replacing brushing treatment, it is known that by irradiating polarized radiation, a light orientation method is given to liquid crystal orientation ability. With regard to the liquid crystal orientation treatment based on the light orientation method, it is proposed: liquid crystal orientation treatment using photoisomerization reaction, liquid crystal orientation treatment using photocrosslinking reaction, liquid crystal orientation treatment using photodecomposition reaction, etc. (refer to non-patent literature 1, patent literature 1).

[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 is the following problem: due to the voltage driving the liquid crystal, charges are accumulated in the liquid crystal alignment film, which affects the display as afterimages and afterimages (hereinafter referred to as afterimages derived from residual DC), significantly reducing the display quality level of the liquid crystal display element. Therefore, a liquid crystal alignment agent that overcomes these problems has been proposed (see Patent Document 2).

[0005] In addition, in the IPS mode and FFS driving mode, the stability of the liquid crystal orientation also becomes important. If the orientation stability is low, the liquid crystal cannot return to the initial state when the liquid crystal is driven for a long time, which becomes the cause of reduced contrast and residual image (hereinafter referred to as AC residual image). As a method for solving the above problems, a specific liquid crystal orientation agent is disclosed in Patent Document 3.

[0006] Furthermore, with the popularization of tablets and smart phones, the development of liquid crystal display elements with narrow frames that ensure the widest possible display area is being promoted. Due to the narrow frame, it is necessary to apply a sealant to the liquid crystal alignment film, so Patent Document 4 discloses: a liquid crystal alignment agent that maintains the liquid crystal orientation and has good adhesion with the sealant.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 9-297313

[0010] Patent Document 2: International Publication No. 2005 / 083504 Pamphlet

[0011] Patent Document 3: International Publication No. 2015 / 050135 Pamphlet

[0012] Patent Document 4: International Publication No. 2015 / 060360 Pamphlet

[0013] Non-patent literature

[0014] Non-patent document 1: "Liquid crystal photo-alignment film" Kidowaki, Ichimura, Functional Materials, November 1997, Vol. 17, No. 11, pp. 13-22 Summary of the invention

[0015] Problems to be solved by the invention

[0016] However, in actual liquid crystal display elements, the twist angle slightly deviates within the surface of the liquid crystal display element due to manufacturing deviations, etc. Therefore, due to such in-plane deviations, the brightness of the black display in the liquid crystal display element deviates within the surface. In addition, the demand for high-precision liquid crystal display elements is further increasing, and it is more important than before to show a good display quality level.

[0017] The present invention has been completed in view of the above situation, and one of its purposes is to provide a liquid crystal alignment agent that can obtain a liquid crystal alignment film that has good resistance to AC afterimages or afterimages derived from residual DC and good adhesion to a sealant, and can obtain a liquid crystal display element that suppresses the deviation of brightness within the plane during black display and has excellent contrast characteristics.

[0018] Solutions for solving problems

[0019] The present inventors have conducted intensive studies and have found that the above-mentioned problems can be solved by using a liquid crystal aligning agent containing specific components, thereby completing the present invention. Specifically, the following aspects are the main gist.

[0020] A liquid crystal aligning agent, characterized in that it contains 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) containing a repeating unit represented by the following formula (3).

[0021]

[0022] (R1 to R4 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group, and at least one of R1 to R4 represents a group other than a hydrogen atom in the above definition. Y1 represents a divalent organic group having a partial structure represented by the following formula (H).)

[0023]

[0024] (Q 3 For -(CH2) n - (where n is an integer of 2 to 20, and any -CH2- is optionally substituted by -O-. However, oxygen atoms are not directly bonded to each other), and any hydrogen atoms on the two benzene rings are optionally substituted by a monovalent organic group. * indicates a bond.)

[0025]

[0026] (X3 represents a tetravalent organic group derived from an aromatic acid dianhydride, Y3 is a divalent organic group having a partial structure represented by the following formula (m), and * is a bonding bond. 30 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; Z 31 , Z 32 Each independently represents a hydrogen atom, 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.)

[0027]

[0028] Effects of the Invention

[0029] According to the liquid crystal aligning agent of the present invention, a liquid crystal aligning film having good adhesion to a sealant can be obtained. In addition, a liquid crystal display element having excellent contrast and being less likely to produce residual images or AC residual images due to residual DC and suppressing the deviation of brightness within the plane during black display can be obtained. DETAILED DESCRIPTION

[0030] <Polymer (A)>

[0031] The liquid crystal aligning agent of the present invention contains a polymer (A) having a repeating unit represented by the above formula (1). By setting such a structure, a liquid crystal aligning film with less AC residual image generation can be obtained, and a liquid crystal display element with excellent contrast can be obtained. In the above formula (1), X2, Y1, Y2, R1, R2, R3, and R4 are as defined above.

[0032] As the tetravalent organic group of X2 in formula (1), a tetravalent organic group having an alicyclic structure of five to eight-membered rings is preferred, and a tetravalent organic group having an alicyclic structure of five to seven-membered rings is more preferred. It should be noted that the alicyclic structure having more than five-membered rings means that when the alicyclic structure to which the imide group is bonded is a polycyclic structure, the number of atoms constituting the ring in each ring contained in the polycyclic structure is 5 or more. In addition, the alicyclic structure only needs to be bonded to at least one of the two imide groups, and may also have an alicyclic structure, a chain hydrocarbon structure, and an aromatic ring structure.

[0033] Specific examples of the alkyl group having 1 to 6 carbon atoms in the above R1 to R4 include: methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, etc. Specific examples of the alkenyl group having 2 to 6 carbon atoms in the above R1 to R4 include: vinyl, propenyl, butenyl, etc., which may be linear or branched. Specific examples of the alkynyl group having 2 to 6 carbon atoms in the above R1 to R4 include: ethynyl, 1-propynyl, 2-propynyl, etc. Specific examples of the halogen atom in the above R1 to R4 include: fluorine atom, chlorine atom, bromine atom, iodine atom, etc. Examples of the monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom include fluoromethyl, trifluoromethyl, etc. From the viewpoint of high photoreactivity, it is preferred that R1 to R4 are hydrogen atoms or methyl groups, preferably at least one of R1 to R4 is a methyl group, more preferably at least two of R1 to R4 are methyl groups, and more preferably R1 and R3 are methyl groups and R2 and R4 are hydrogen atoms.

[0034] Specific examples of the monovalent organic group in the formula (H) include: halogen atoms, alkyl groups having 1 to 6 carbon atoms, alkenyl groups having 2 to 6 carbon atoms, alkynyl groups having 2 to 6 carbon atoms, and monovalent organic groups having 1 to 6 carbon atoms containing fluorine atoms, and the structures exemplified in the above R1 to R4 can be listed. As the partial structure represented by the formula (H), from the viewpoint of less generation of AC afterimages, the partial structure represented by any of the following formulas (H-1) to (H-6) can be listed.

[0035]

[0036] Preferred specific examples of Y1 in the formula (1) include divalent organic groups represented by any one of the following formulae (h-1) to (h-7) from the viewpoint of reducing the occurrence of AC afterimages.

[0037]

[0038] From the viewpoint of improving heat resistance, the polymer (A) preferably further has a repeating unit represented by the following formula (2).

[0039]

[0040] (In the formula, X2 is a tetravalent organic group having an alicyclic structure of five or more members. Y2 represents a divalent organic group having a partial structure represented by the above formula (H).)

[0041] As the tetravalent organic group of X2 in formula (2), a tetravalent organic group having an alicyclic structure of five to eight-membered rings is preferred, and a tetravalent organic group having an alicyclic structure of five to seven-membered rings is more preferred. It should be noted that the alicyclic structure having more than five-membered rings means that when the alicyclic structure to which the imide group is bonded is a polycyclic structure, the number of atoms constituting the ring in each ring contained in the polycyclic structure is 5 or more. In addition, the alicyclic structure only needs to be bonded to at least one of the two imide groups, and may also have an alicyclic structure, a chain hydrocarbon structure, and an aromatic ring structure.

[0042] Preferred specific examples of X2 include a tetravalent organic group represented by any one of the following formulae (X2-1) to (X2-12).

[0043]

[0044] From the viewpoint of reducing the occurrence of AC afterimages and improving the contrast of a liquid crystal display element, (X2-1) to (X2-4) are more preferred.

[0045] Preferred specific examples of Y2 in the above formula (2) are the same as preferred specific examples of Y1 in the above formula (1).

[0046] From the viewpoint of improving the contrast of a liquid crystal display element, the polymer (A) 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).

[0047]

[0048] In the formulas (4) and (5), R 41 To R 44 Including preferred specific examples, they have the same meanings as R1 to R4 in the above formula (1). X5 in the formula (5) has the same meaning as X2 in the above formula (2). Y4 and Y5 represent a divalent organic group represented by the following formula (I).

[0049]

[0050] In the formula (I), Q represents a single bond or an oxygen atom, and n represents 0 to 2. Any hydrogen atom on the benzene ring may be substituted with a monovalent organic group, and examples of such a monovalent organic group include the structures exemplified in the specific examples of the monovalent organic group in the formula (H).

[0051] From the viewpoint of improving the contrast of a liquid crystal display element, it is preferred that Y4 in the formula (4) and Y5 in the formula (5) are divalent organic groups represented by any one of the following formulae (I-1) to (I-3). In the following formulae, * represents a bonding bond.

[0052]

[0053] From the viewpoint of improving the adhesion with the sealant, the polymer (A) may further have at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (6) and a repeating unit represented by the following formula (7).

[0054]

[0055] (Where R 61 To R 64 Including preferred specific examples, they are synonymous with R1 to R4 of the above formula (1), and Y6 and Y7 each independently represent a divalent organic group having a partial structure represented by the following formula (J-1) or a divalent organic group represented by the following formula (J-2). X7 in formula (7) is synonymous with X2 in formula (2).

[0056]

[0057] In the formula (J-1) and (J-2), Q5 is a single bond, -(CH2) n-(n is an integer from 1 to 20) or -(CH2) n Any -CH2- in - is replaced by -O-, -COO-, -OCO-, -NQ9-, -NQ9CO-, -CONQ9-, -NQ9CONQ 10 -, -NQ9COO-, -OCOO-substituted groups, Q9 and Q 10 Each independently represents a hydrogen atom or a monovalent organic group; Q6 and Q7 independently represent -H, -NHD, -N(D)2, a group having -NHD, or a group having -N(D)2. Q8 represents -NHD, -N(D)2, a group having -NHD, or a group having -N(D)2. D represents a carbamate protecting group, and examples of the carbamate protecting group include tert-butoxycarbonyl and 9-fluorenylmethoxycarbonyl. Among them, at least one of Q5, Q6, and Q7 has a carbamate protecting group in the group. *1 represents a bonding bond. Preferred specific examples of Y6 and Y7 include divalent organic groups represented by any of the following formulas (J-1-a) to (J-1-d) and (J-2-1) from the viewpoint of less AC afterimage. "Boc" represents tert-butoxycarbonyl.

[0058]

[0059] In addition to the repeating unit represented by the above formula (1), the repeating unit represented by the above formula (2), the repeating unit represented by the above formula (4), the repeating unit represented by the above formula (5), the repeating unit represented by the above formula (6) and the repeating unit represented by the above formula (7), the polymer (A) may also have at least one repeating unit selected from the group consisting of the repeating unit represented by the following formula (PI-A-1) and the repeating unit represented by (PA-1).

[0060]

[0061] In the formula (PI-A-1), X I1 represents a tetravalent organic group, Y I1 represents a divalent organic group. I1 When Y is the same as the tetravalent organic group represented by the following formula (g) or X2 in the above formula (2), I1 represents a structure other than the divalent organic group having a partial structure represented by the formula (H), the divalent organic group represented by the formula (I), the divalent organic group having a partial structure represented by the formula (J-1), and the divalent organic group represented by the formula (J-2). I1 In addition to the tetravalent organic group represented by the following formula (g) and the tetravalent organic group exemplified in X2 of the above formula (2), the following formula (XI1 -1)~(X I1 -13) and a tetravalent organic group derived from an aromatic tetracarboxylic dianhydride.

[0062]

[0063] (R1, R2, R3, and R4 have the same meanings as R1, R2, R3, and R4 in the above formula (1).)

[0064]

[0065] Here, the aromatic tetracarboxylic dianhydride refers to an acid dianhydride obtained by intramolecular dehydration of a carboxyl group bonded to an aromatic ring such as a benzene ring or a naphthalene ring. Specific examples include a tetravalent organic group represented by any of the following formulas (X3-1) to (X3-2) and a tetravalent organic group represented by any of the following formulas (Xr-1) to (Xr-7).

[0066]

[0067] (x and y are each independently a single bond, an ether bond (-O-), a carbonyl group (-CO-), an ester bond (-COO-), an alkanediyl group having 1 to 5 carbon atoms, a 1,4-phenylene group, a sulfonyl group or an amide group. j and k are each independently an integer of 0 or 1. * represents a bond.)

[0068]

[0069] As Y in formula (PI-A-1) I1 Specific examples of the divalent organic group include, in addition to the divalent organic group having a partial structure represented by the formula (H), the divalent organic group represented by the formula (I), the divalent organic group having a partial structure represented by the formula (J-1), and the divalent organic group represented by the formula (J-2), the following divalent organic groups represented by formulas (o-1) to (o-23), and the group represented by any of the formulas (Y-1) to (Y-167) described in International Publication No. 2018 / 117239.

[0070]

[0071] In formula (PA-1), X A1 represents a tetravalent organic group, Y A1 represents a divalent organic group. A1 Specific examples include X of the formula (PI-A-1) I1 The structure shown in the example, as Y A1 Specific examples include Y of the formula (PI-A-1):I1 The structure shown in the example.

[0072] In formula (PA-1), R A1 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; Z A11 , Z A12 Each is independently a hydrogen atom, 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.

[0073] As the above R A1 Specific examples of the alkyl group having 1 to 5 carbon atoms include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, etc. From the viewpoint of ease of imidization by heating, R1 is preferably a hydrogen atom or a methyl group.

[0074] As the above Z A11 , Z A12 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. A11 , Z A12 Specific examples of alkenyl groups having 2 to 10 carbon atoms include vinyl, propenyl, butenyl, etc., which may be linear or branched. A11 , Z A12 Specific examples of the alkynyl group having 2 to 10 carbon atoms include ethynyl, 1-propynyl, and 2-propynyl.

[0075] Z A11 , Z A12 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.

[0076] From the viewpoint of reducing AC afterimages, the total amount of the repeating unit represented by the formula (1) and the repeating unit represented by the formula (2) in the polymer (A) is preferably 1 to 95 mol% of all the repeating units.

[0077] <Polymer (B)>

[0078] The liquid crystal aligning agent of the present invention contains a polymer (B) having a repeating unit represented by the above formula (3). By setting such a structure, the heat resistance of the obtained liquid crystal aligning film can be improved, so that a liquid crystal aligning film with less AC residual image can be obtained, and the deviation of the in-plane torsion angle generated during the manufacturing process can be suppressed, and a liquid crystal display element with excellent contrast can be obtained. In the above formula (3), X3, Y3, R 30 , Z 31 , Z 32 As defined above.

[0079] As the above R 30 Specific examples of the alkyl group having 1 to 5 carbon atoms include R in the above formula (PA-1): A1 From the perspective of ease of imidization by heating, R 30 Preferably, they are each independently a hydrogen atom or a methyl group.

[0080] As the above Z 31 , Z 32 Specific examples of the alkyl group having 1 to 10 carbon atoms, the alkenyl group having 2 to 10 carbon atoms, and the alkynyl group having 2 to 10 carbon atoms include Z in the above formula (PA-1): A1 , Z A2 The structure shown as an example, etc.

[0081] Z 31 , Z 32 It may have a substituent, and examples of the substituent include Z in the above formula (PA-1): A1 , Z A2 The structure shown as an example, etc.

[0082] From the perspective of less afterimage in AC, Z 31 , Z 32 Preferably, they are each independently a hydrogen atom or a methyl group.

[0083] As Y3 in the formula (3), from the viewpoint of reducing AC afterimages, a divalent organic group selected from the following formulae (Y3-1) to (Y3-2) may be used.

[0084]

[0085] Specific examples of the aromatic acid dianhydride in X3 of the formula (3) include the above-mentioned X I1 The structure shown as an example. From the viewpoint of less AC afterimage, X3 is preferably a tetravalent organic group represented by the formula (X3-1) or (X3-2). As a tetravalent organic group represented by the formula (X3-1) or (X3-2), a more preferred specific example is a structure represented by any one of the following formulas (X3-3) to (X3-19).

[0086]

[0087]

[0088] From the viewpoint of improving the sealing adhesion of the liquid crystal alignment film and reducing the afterimage caused by the residual DC, the polymer (B) may have at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (8) and a repeating unit represented by the following formula (9).

[0089]

[0090] (In the formula, X8 is a tetravalent organic group having an alicyclic structure of more than five-membered rings, and is synonymous with X2 in the formula (2) including the preferred embodiment. X9 is a tetravalent organic group having an alicyclic structure of more than five-membered rings or a tetravalent organic group derived from an aromatic acid dianhydride, and is synonymous with X2 in the formula (2) or X3 in the formula (3) including the preferred embodiment. Y8 is synonymous with Y3 in the formula (3), and Y9 is a divalent organic group having a partial structure represented by the following formula (n-1) or (n-2). Z 81 , Z 82 , Z 91 , Z 92 Respectively with Z of the formula (3) 31 , Z 32 R8 and R9 are independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and Q1 and Q2 are independently a hydrogen atom or a methyl group.

[0091]

[0092] Specific examples of the divalent organic group having a partial structure represented by the formula (n-1) or (n-2) include structures represented by any of the following formulae (ND-1-2), (ND-2-1) to (ND-2-3), and (ND-5).

[0093]

[0094] (R 21 and R 22 Each independently represents a hydrogen atom or a methyl group, Q 22 Each independently represents a single bond or *1-R 23 -Ph-*2, R 23 represents a single bond, selected from -O-, -COO-, -OCO-, -(CH2) l -, -O(CH2) mO-, -CONH- and -NHCO- are divalent organic groups (l and m represent integers of 1 to 5, *1 represents a site bonded to the benzene ring in the formula (ND-1-2), and *2 represents a site bonded to the amino group in the formula (ND-1-2). Ph represents a phenylene group. n represents an integer of 1 to 3.)

[0095]

[0096] In the formula, R 21 , R 22 are hydrogen atoms or methyl groups. 24 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 such as a methyl group, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.).

[0097]

[0098] In the formula, R 25 represents a single bond, selected from -O-, -COO-, -OCO-, -(CH2) l -, -O(CH2) m In the divalent organic group of O-, -CONR- and -NRCO-, k represents an integer of 1 to 5. In addition, R represents a monovalent organic group such as hydrogen or an alkyl group having 1 to 3 carbon atoms, 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 (ND-2-1) to formula (ND-2-3).

[0099]

[0100] (R 51 , R 52 A5 represents a single bond or -O-, -(CH2) n -(n is an integer of 1 to 4) etc. divalent organic groups.

[0101] Preferred specific examples of the formula (ND-1-2) include structures represented by any one of the following formulae (n1-9) to (n1-14).

[0102]

[0103] Preferred specific examples of the formulae (ND-2-1) to (ND-2-3) include structures represented by any one of the following formulae (n2-1) to (n2-6).

[0104]

[0105] Preferred specific examples of the formula (ND-5) include structures represented by any one of the following formulae (n5-1) to (n5-8).

[0106]

[0107] The polymer (B) may have a repeating unit represented by the following formula (PA-2) in addition to the repeating unit represented by the above formula (3), the repeating unit represented by the above formula (8), and the repeating unit represented by the above formula (9).

[0108]

[0109] In formula (PA-2), X A2 represents a tetravalent organic group, and Y A2 represents a divalent organic group. A2 When Y has the same meaning as X9 in the above formula (9), A2 represents a structure other than the divalent organic group having a partial structure represented by the above formula (m) or the divalent organic group having a partial structure represented by the above formula (n-1) or (n-2). A2 Including preferred embodiments, it has the same meaning as R3 in the formula (3), Z A21 , Z A22 Including the preferred embodiment and Z of the formula (3) 31 , Z 32 Synonymous.

[0110] As X A2 Specific examples include, in addition to the aromatic tetracarboxylic dianhydride exemplified as X3 in the above formula (3), tetravalent organic groups derived from aliphatic tetracarboxylic dianhydride and alicyclic tetracarboxylic dianhydride.

[0111] As Y A2Specific examples include, in addition to the divalent organic group having a partial structure represented by the formula (m) or the divalent organic group having a partial structure represented by the formula (n-1) or (n-2), a divalent organic group having a pyrrole structure described in International Publication WO2017 / 126627, preferably a divalent organic group represented by the following formula (pr), a divalent organic group having a thiophene or furan structure described in International Publication WO2018 / 092759, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzene Methanol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid or 3,5-diaminobenzoic acid, a divalent organic group obtained by removing two amino groups from a diamine having a carboxyl group such as a diamine compound represented by the following formula [3b-1] to [3b-4], a divalent organic group having -NH-CO-NH- in the molecule such as the following formula (U-1) to (U-9), a divalent organic group described in paragraphs 0013 to 0030 of International Publication No. WO2018-181566, and the like.

[0112]

[0113] In formula (pr), R 81 represents a hydrogen atom or a methyl group, R 82 Each independently represents a single bond or a group "*1-R 83 -Ph-*2”,R 83 represents a single bond, selected from -O-, -COO-, -OCO-, -(CH2) l -, -O(CH2) m The divalent organic group (l, m represents integers of 1 to 5) in O-, -CONH- and -NHCO-, *1 represents the site bonded to the benzene ring in formula (pr), and *2 represents the site bonded to the nitrogen atom in the above formula (PA-2). Ph represents a phenylene group. n represents 1 to 3.

[0114]

[0115] In formula [3b-1], A 1 represents a single bond, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CH2O-, -OCH2-, -COO-, -OCO-, -CON(CH3)-, or N(CH3)CO-, m 1 and m 2 Each independently represents an integer from 0 to 4, and m 1 +m 2represents an integer from 1 to 4, in formula [3b-2], m 3 and m 4 Each independently represents an integer of 1 to 5. In the formula [3b-3], A 2 represents a straight or branched alkylene group having 1 to 5 carbon atoms, m 5 represents an integer of 1 to 5, in formula [3b-4], A 3 and A 4 Each independently represents a single bond, -CH2-, -C2H4-, -C(CH3)2-, -CF2-, -C(CF3)2-, -O-, -CO-, -NH-, -N(CH3)-, -CONH-, -NHCO-, -CH2O-, -OCH2-, -COO-, -OCO-, -CON(CH3)- or N(CH3)CO-, m 6 Represents integers from 1 to 4.

[0116]

[0117] From the viewpoint of improving contrast, the polymer (B) of the present invention preferably contains 30 to 100 mol % of the repeating unit represented by the above formula (3) relative to all repeating units of the polymer (B), or preferably contains 40 to 100 mol %, or preferably contains 50 to 100 mol %.

[0118] From the viewpoint of less AC afterimage and afterimage derived from residual DC, the mixing ratio of the polymer (A) to the 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 alignment film with high reproducibility, the mixing ratio of the polymer (A) to the polymer (B) is more preferably 10 / 90 to 90 / 10, and further preferably 20 / 80 to 80 / 20 in terms of the mass ratio of polymer (A) / polymer (B).

[0119] <Production method of polyamic acid, polyamic acid ester, and polyimide>

[0120] The polyamic acid ester, the polyamic acid, and the polyimide which are polyimide precursors used in the present invention can be synthesized by a known method described in, for example, International Publication WO2013 / 157586.

[0121] <Liquid crystal alignment agent>

[0122] The liquid crystal aligning agent of the present invention contains a polymer (A) and a polymer (B). 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 the types of other polymers, there can be listed: 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.

[0123] 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 polymer component and an organic solvent is also preferred. At this time, the concentration of the polymer in the liquid crystal alignment agent can be appropriately changed according to the setting of the thickness of the coating film to be formed. From the perspective of forming a uniform and defect-free coating film, it is preferably more than 1% by mass, and from the perspective of the storage stability of the solution, it is preferably less than 10% by mass. The concentration of the polymer is particularly preferably 2 to 8% by mass.

[0124] 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 listed, they include: N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, 1, 3-dimethyl-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide (they are also collectively referred to as "good solvents"), etc. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide or γ-butyrolactone is preferably used. The good solvent in the liquid crystal aligning agent of the present invention is preferably 20 to 99% by mass of the whole solvent contained in the liquid crystal aligning agent, more preferably 20 to 90% by mass, particularly preferably 30 to 80% by mass.

[0125] 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. Specific examples of the organic solvents used are listed in the following content, but are not limited to these examples.

[0126] 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, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisopentyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol, 2 -(2-Butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol acetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl 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.

[0127] Among them, diisobutylcarbinol, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate or diisobutyl ketone is preferred.

[0128] 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 2,6-dimethyl-4-heptanone; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and diisopropyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether and 2,6-dimethyl-4-heptanol; N-methyl-2-pyrrolidone, γ-butyrolactone and dipropylene glycol dimethyl ether; N-methyl-2-pyrrolidone, γ-butyrolactone and dipropylene glycol dimethyl ether; N-methyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol dimethyl ether, etc. These poor solvents are preferably 1 to 80% by mass of the total solvent contained in the liquid crystal alignment agent, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass. The type and content of such solvents are appropriately selected according to the coating device, coating conditions, coating environment, etc. of the liquid crystal alignment agent.

[0129] 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 bonding aid for improving the adhesion between the liquid crystal aligning film and the substrate, the adhesion between the liquid crystal aligning film and the sealant, a compound for improving the strength of the liquid crystal aligning film (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.

[0130] As the cross-linking compound, from the viewpoint of less generation of AC afterimages and greater improvement in film strength, preferred are an oxiranyl group, an oxetane group, a protected isocyanate group, a protected isothiocyanate group, a group containing an oxazoline ring structure, a group containing a Meldrum acid structure, a cyclic carbonate group, a compound having a group represented by the following formula (d) or a compound represented by the following formula (e) (these are also collectively referred to as compound (C)).

[0131]

[0132] In formula (d) and (e), R 71 , R 72 and R 73 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 (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.

[0133] 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 in the skeleton described in International Publication No. WO2017 / 170483, and the like. Among them, compounds containing nitrogen atoms such as 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 represented by any of the following formulas (r-1) to (r-3) are particularly preferred.

[0134]

[0135] Specific examples of the compound having an oxetane group include compounds having two or more oxetane groups described in paragraphs 0170 to 0175 of International Publication No. 2011 / 132751.

[0136] Specific examples of compounds having protected isocyanate groups include compounds having two or more protected isocyanate groups described in paragraphs 0046 to 0047 of Japanese Patent Application Publication No. 2014-224978, compounds having three or more protected isocyanate groups described in paragraphs 0119 to 0120 of International Publication No. 2015 / 141598, etc. Among them, compounds represented by any one of the following formulas (bi-1) to (bi-3) are preferred.

[0137]

[0138] 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.

[0139] 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.

[0140] Specific examples of the compound having a group containing a Michaelis acid structure include compounds having two or more Michaelis acid structures described in International Publication No. WO2012 / 091088.

[0141] Specific examples of the compound having a cyclic carbonate group include compounds described in International Publication No. WO2011 / 155577.

[0142] As R in the formula (d) 71 , R 72 , R 73 The alkyl group having 1 to 3 carbon atoms includes, for example, a methyl group, an ethyl group, and a propyl group.

[0143] Specific examples of the compound having a group represented by the formula (d) include, for example, the compound having two or more groups represented by the formula (d) described in International Publication No. WO2015 / 072554, paragraph 0058 of Japanese Patent Application Publication No. 2016-118753, and the compound described in Japanese Patent Application Publication No. 2016-200798. Among them, the compound represented by any one of the following formulas (hd-1) to (hd-8) is preferred.

[0144]

[0145] Examples of the (m+n)-valent organic group having an aromatic ring in A of the formula (e) include: an (m+n)-valent aromatic hydrocarbon group having 5 to 30 carbon atoms, an (m+n)-valent organic group to which an aromatic hydrocarbon group having 5 to 30 carbon atoms is directly or via a linking group, and an (m+n)-valent group having an aromatic heterocyclic ring. Examples of the aromatic hydrocarbon group include benzene and naphthalene. 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, an acridine ring, and the like. Examples of the linking group include: an alkylene group having 1 to 10 carbon atoms, a group obtained by removing one hydrogen atom from the alkylene group, a divalent or trivalent cyclohexane ring, and the like. It should be noted that any hydrogen atom of the alkylene group may be substituted by an organic group such as a fluorine atom or a trifluoromethyl group. Specific examples include compounds described in International Publication No. WO2010 / 074269. As preferred specific examples, any of the following formulas (e-1) to (e-9) may be cited.

[0146]

[0147] Examples of the crosslinking compound are not limited to these. For example, components other than the above disclosed in International Publication Nos. 2015 / 060357 to 2015 / 060357 can be cited. In addition, two or more crosslinking compounds can be used in combination.

[0148] The content of the crosslinking compound in the liquid crystal aligning agent of the present invention is preferably 0.5 to 20 parts by mass, and more preferably 1 to 15 parts by mass, relative to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent, from the viewpoint of achieving the target effect and reducing the occurrence of AC afterimages.

[0149] 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, N-ethyl Oxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N -phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis(ethylene oxide)-3-aminopropyltrimethoxysilane, N-bis(ethylene oxide)-3-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxy Silane coupling agents such as triethoxypropylsilane, trimethoxypropyltrimethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, tris(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatepropyltriethoxysilane are used. When using these silane coupling agents, from the viewpoint of less generation of AC residual images, the amount of the silane coupling agent used 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.

[0150] <Method for producing liquid crystal alignment film>

[0151] The method for manufacturing a liquid crystal alignment film using the liquid crystal alignment agent of the present invention is characterized in that it includes: a process of applying the above-mentioned liquid crystal alignment agent (process (A)); a process of heating the coating film of the liquid crystal alignment agent obtained in process (A) to obtain a film (process (B)); and a process of irradiating polarized ultraviolet rays to the film obtained in process (B) (process (C)), and preferably includes: a process of calcining the film obtained in process (C) at a temperature above 100°C and higher than that in process (B) (process (D)).

[0152] <Process (A)>

[0153] As the substrate coated with the liquid crystal alignment agent used in the present invention, there is no particular limitation as long as it is a substrate with high transparency, and the following can be used together: glass substrate; silicon nitride substrate; plastic substrates such as acrylic substrates and polycarbonate substrates. In this case, if a substrate having an ITO electrode or the like for driving the liquid crystal is used, it is preferred from the perspective of simplifying the process. In addition, in a reflective liquid crystal display element, if only a single-sided substrate is used, an opaque object such as a silicon wafer can be used, and the electrode in this case can use a light-reflecting material such as aluminum.

[0154] The coating method of the liquid crystal alignment agent is not particularly limited, and is generally performed industrially by screen printing, gravure printing, flexographic printing, or inkjet printing, etc. Other coating methods include dipping, roll coating, slit coating, spin coating, or spray coating, and they can be used according to the purpose.

[0155] <Process (B)>

[0156] Step (B) is a step of firing the liquid crystal aligning agent applied on the substrate to form a film. After the liquid crystal aligning agent is applied on the substrate, the solvent can be evaporated or the thermal imidization of the amic acid or amic acid ester in the polymer can be performed by a heating unit such as a heating plate, a thermal circulation oven or an IR (infrared) oven. The drying and firing steps after the liquid crystal aligning agent of the present invention is applied can be selected at any temperature and time, and can be performed multiple times. As the temperature for removing the organic solvent of the liquid crystal aligning agent, for example, it can be carried out in a temperature range of 40 to 150°C. From the perspective of shortening the process, it can also be carried out within 40 to 120°C. The firing time is not particularly limited, and a firing time of 1 to 10 minutes or 1 to 5 minutes can be listed. In the case of thermal imidization of the amic acid or amic acid ester in the polymer, after the step of removing the above-mentioned organic solvent, the firing process can be carried out in a temperature range of 190 to 250°C or 200 to 240°C, for example. The firing time is not particularly limited, and examples thereof include a firing time of 5 to 40 minutes or 5 to 30 minutes.

[0157] <Process (C)>

[0158] Step (C) is a step of irradiating the film obtained in step (B) with polarized ultraviolet rays. As ultraviolet rays, ultraviolet rays with a wavelength of 200 to 400 nm are preferably used, and ultraviolet rays with a wavelength of 200 to 300 nm are more preferably used. In order to improve the orientation of the liquid crystal, the substrate coated with the liquid crystal orientation film can be heated at 50 to 250°C while irradiating with ultraviolet rays. In addition, the irradiation amount of the radiation is preferably 1 to 10,000 mJ / cm 2 Among them, 100 to 5000 mJ / cm 2 The liquid crystal alignment film produced in this way can stably align the liquid crystal molecules in a certain direction.

[0159] The higher the extinction ratio of the polarized ultraviolet light, the higher the anisotropy can be imparted, which is preferred. Specifically, the extinction ratio of the linearly polarized ultraviolet light is preferably 10:1 or more, and more preferably 20:1 or more.

[0160] <Process (D)>

[0161] Step (D) is a step of firing the film obtained in step (C) at a temperature of 100°C or higher and higher than that in step (B). The firing temperature is not particularly limited as long as it is 100°C or higher and higher than the firing temperature in step (B), but is preferably 150 to 300°C, more preferably 150 to 250°C, and even more preferably 200 to 250°C. The firing time is preferably 5 to 120 minutes, more preferably 5 to 60 minutes, and even more preferably 5 to 30 minutes.

[0162] When the thickness of the liquid crystal aligning film after baking is too thin, the reliability of the liquid crystal display element may decrease, and therefore, the thickness of the liquid crystal aligning film is preferably 5 to 300 nm, more preferably 10 to 200 nm.

[0163] And after performing any one of the said process (C) or (D), you may also perform contact treatment with water or a solvent on the obtained liquid crystal aligning film.

[0164] As a solvent used for the above-mentioned contact treatment, there is no particular limitation as long as it is a solvent that dissolves the decomposition product generated by the liquid crystal alignment film by irradiating ultraviolet rays. As specific examples, water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate or cyclohexyl acetate can be listed. Among them, from the perspective of versatility and the safety of the solvent, water, 2-propanol, 1-methoxy-2-propanol or ethyl lactate are preferred. Water, 1-methoxy-2-propanol or ethyl lactate are more preferred. Solvents can also be used in combination of two or more.

[0165] As the above-mentioned contact treatment, that is, the liquid crystal alignment film irradiated with polarized ultraviolet rays is treated with water or solvent, immersion treatment and spray treatment (also called spray treatment) can be listed. From the perspective of efficiently dissolving the decomposition products generated by the liquid crystal alignment film through ultraviolet rays, the treatment time of these treatments is preferably 10 seconds to 1 hour. Among them, it is preferred to perform an immersion treatment for 1 minute to 30 minutes. In addition, the solvent during the contact treatment can be at room temperature or heated, preferably 10 to 80°C. Among them, 20 to 50°C is preferred. In addition, from the perspective of the solubility of the decomposition product, ultrasonic treatment or the like can also be performed as needed.

[0166] After the contact treatment, it is preferred to perform rinsing (also referred to as leaching) with a low boiling point solvent such as water, methanol, ethanol, 2-propanol, acetone or methyl ethyl ketone, and calcining of the liquid crystal alignment film. At this time, either leaching or calcining may be performed, or both may be performed. The calcining temperature is preferably 150 to 300°C. Among them, 180 to 250°C is preferred. 200 to 230°C is more preferred. In addition, the calcining time is preferably 10 seconds to 30 minutes. Among them, 1 to 10 minutes is preferred.

[0167] 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 a liquid crystal display element of an 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.

[0168] As an example of a method for manufacturing a liquid crystal unit, a passive matrix liquid crystal display element is described 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.

[0169] Specifically, a transparent glass substrate is prepared, a common electrode is provided on one substrate, and a segment electrode is provided on the other substrate. These electrodes can be provided, for example, as ITO electrodes, and patterned in a manner that enables a desired image display. Next, an insulating film is provided on each substrate in a manner that covers the common electrode and the segment electrode. The insulating film can be provided, for example, as a SiO2-TiO2 film formed by a sol-gel method.

[0170] Next, a liquid crystal alignment film is formed on each substrate, and the substrate of one side is overlapped 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 with a sealant. In order to control the gap between the substrates, spacers are usually mixed in the sealant. In addition, it is preferred to also 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 of a positive liquid crystal material and a negative liquid crystal material. Next, a polarizing plate is set. Specifically, a pair of polarizing plates are bonded to the surface opposite to the liquid crystal layer of the two substrates.

[0171] As described above, by using the manufacturing method of the present invention, it is possible to suppress the residual image caused by long-term AC driving in the liquid crystal display elements of the IPS driving method and the FFS driving method. In addition, in step (B), after removing the organic solvent in the temperature range of 40 to 150°C, step (C) is implemented, thereby obtaining a liquid crystal alignment film with fewer steps than before. The liquid crystal alignment agent of the present invention can be particularly preferably used in a method for manufacturing a liquid crystal alignment film comprising the following steps: in step (B), after removing the organic solvent in the temperature range of 40 to 150°C, step (C) is implemented.

[0172] As described above, by using the liquid crystal aligning agent of the present invention, the generation of residual images from residual DC and AC residual images is small, and a liquid crystal aligning film with high sealing adhesion can be obtained. In addition, a liquid crystal display element with excellent contrast in which the deviation of the brightness within the surface during black display is suppressed can be obtained, and a liquid crystal display element with a good display quality grade can be obtained.

[0173] [Example]

[0174] The present invention will be described in more detail below with reference to Examples, but the present invention is not limited thereto. The abbreviations of the following compounds and the methods for measuring the properties are as follows.

[0175] (Solvent)

[0176] NMP: N-methyl-2-pyrrolidone, GBL: gamma-butyrolactone. BCS: butyl cellosolve.

[0177] (Diamine)

[0178] DA-1 to DA-8: compounds represented by the following formulas (DA-1) to (DA-8).

[0179] (Tetracarboxylic dianhydride)

[0180] CA-1 to CA-4: compounds represented by the following formulas (CA-1) to (CA-4).

[0181] (additive)

[0182] C-1: A compound represented by the following formula (C-1).

[0183] C-2: 2,2'-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane.

[0184]

[0185] S-1: A compound represented by the following formula (S-1).

[0186]

[0187] <Viscosity>

[0188] The measurement was performed at a temperature of 25° C. using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample amount of 1.1 mL and a conical rotor TE-1 (1°34′, R24).

[0189] <Measurement of Imidization Ratio>

[0190] 20 mg of polyimide powder was added to an NMR sample tube (NMR standard sampling tube, φ5 (manufactured by Kusano Scientific Co., Ltd.)), deuterated dimethyl sulfoxide (DMSO-d6, 0.05% TMS (tetramethylsilane) mixture) (0.53 ml) was added, and ultrasonic waves were applied 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 amide acid appearing near 9.5 ppm to 10.0 ppm is used to calculate it using the following formula.

[0191] Imidization rate (%) = (1-α·x / y) × 100

[0192] 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%).

[0193] [Synthesis Example of Polymer]

[0194] Synthesis examples of polyamic acid and polyimide are shown below. In addition, in these nomenclatures, A represents (A) component, B represents (B) component, and PI represents polyimide.

[0195] <Synthesis example 1>

[0196] 4.89 g (20.0 mmol) of DA-1, 2.59 g (24.0 mmol) of DA-2, 4.61 g (20.0 mmol) of DA-3 and 5.46 g (16.0 mmol) of DA-5 were weighed into a 300 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, and 197 g of NMP was added, and the mixture was stirred and dissolved while nitrogen was supplied. While stirring the diamine solution, 14.2 g (63.2 mmol) of CA-1 and 3.00 g (12.0 mmol) of CA-2 were added, and the mixture was stirred at 40° C. for 24 hours to obtain a polyamic acid solution (A-1) (viscosity: 425 mPa·s).

[0197] <Synthesis example 2>

[0198] In a 1L separable flask equipped with a stirring device and a nitrogen inlet tube, 52.6g (0.264mol) of DA-7 and 13.1g (0.066mol) of DA-8 were weighed, and 481.7g of NMP was added, and the mixture was dissolved while stirring while nitrogen was supplied. While stirring the diamine solution, 41.3g (0.165mol) of CA-2 and 124.5g of NMP were added, and the mixture was reacted at 50°C for 4 hours. Then, 45.1g (0.153mol) of CA-4 and 255.8g of NMP were added, and the mixture was stirred at 70°C for 24 hours to obtain a 15wt% polyamic acid solution (B-1) (viscosity: 895mPa·s).

[0199] <Synthesis Example 3>

[0200] 3.42 g (0.014 mol) of DA-1 was weighed into a 100 mL four-necked flask equipped with a stirring device and a nitrogen inlet tube, and 30.8 g of NMP was added, and the mixture was dissolved while nitrogen was supplied. While stirring the diamine solution, 3.62 g (0.012 mol) of CA-4 and 20.0 g of NMP were added, and the mixture was stirred at 50° C. for 12 hours to obtain a 12 wt% polyamic acid solution (B-2) (viscosity: 129 mPa·s).

[0201] <Synthesis example 4>

[0202] In a 500 mL separable flask equipped with a stirring device and a nitrogen inlet tube, 16.4 g (0.035 mol) of DA-6 and 22.2 g (0.091 mol) of DA-1 were weighed, and 283.6 g of NMP was added, and the mixture was dissolved while nitrogen was supplied. While stirring the diamine solution, 6.51 g (0.026 mol) of CA-2 and 47.7 g of NMP were added, and the mixture was reacted at 50° C. for 2 hours. Then, 28.8 g (0.098 mol) of CA-4 and 87.9 g of NMP were added, and the mixture was stirred for 12 hours to obtain a 15 wt% polyamic acid solution (B-3) (viscosity: 791 mPa·s).

[0203] <Synthesis example 5>

[0204] In a 300mL four-necked flask with a stirring device and a nitrogen inlet tube, 100g of the obtained polyamic acid solution (A-1) was measured, 50g of NMP was added, and stirred for 30 minutes. 16.78g of anhydrous acetic acid and 5.20g of pyridine were added to the obtained polyamic acid solution, and heated at 50°C for 3 hours for chemical imidization. The obtained reaction solution was put into 600ml of methanol while stirring, and the precipitate was filtered out. After washing the resin powder by performing the same operation twice, it was dried at 60°C for 12 hours to obtain a polyimide resin powder. The imidization rate of the polyimide resin powder was 71%. 3.60g of the obtained polyimide resin powder was taken to a 100ml conical flask, 26.4g of NMP was added to make the solid content concentration 12%, and it was stirred at 70°C for 24 hours to dissolve it, and a polyimide solution (A-1-PI) was obtained.

[0205] The main points of the polyamic acid solutions and polyimide solutions obtained in Synthesis Examples 1 to 5 are shown in Table 1 below.

[0206] [Table 1]

[0207]

[0208] The values ​​in parentheses in Table 1 indicate the mixing ratio (mol parts) of each compound relative to 100 mol parts of the total amount of the tetracarboxylic acid derivatives 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 acid 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.

[0209] [Preparation of Liquid Crystal Alignment Agent]

[0210] <Comparative Example 1>

[0211] Into a 20 ml sample tube containing a stirrer, 3.00 g of the polyimide solution (A-1-PI) and 3.60 g of the polyamic acid solution (B-1) were weighed, and further 0.63 g of NMP, 3.60 g of GBL, 3.0 g of BCS, 0.90 g of a GBL solution containing 1 wt % of S-1, and 0.27 g of an NMP solution containing 10 wt % of C-1 were added, and stirred for 30 minutes using a magnetic stirrer to obtain a liquid crystal aligning agent (R1).

[0212] <Example 1>

[0213] Into a 20 ml sample tube containing a stirrer, 3.67 g of the polyimide solution (A-1-PI) and 5.50 g of the polyamic acid solution (B-2) were weighed, and further 0.50 g of NMP, 4.90 g of GBL, 4.00 g of BCS, 1.10 g of a GBL solution containing 1 wt % of S-1, and 0.33 g of an NMP solution containing 10 wt % of C-1 were added, and stirred for 30 minutes using a magnetic stirrer to obtain a liquid crystal aligning agent (1).

[0214] <Example 2>

[0215] Into a 20 ml sample tube containing a stirrer, 3.00 g of the polyimide solution (A-1-PI) and 3.60 g of the polyamic acid solution (B-3) were weighed, and further 0.63 g of NMP, 3.60 g of GBL, 3.0 g of BCS, 0.90 g of a GBL solution containing 1 wt % of S-1, and 0.27 g of an NMP solution containing 10 wt % of C-1 were added, and stirred for 30 minutes using a magnetic stirrer to obtain a liquid crystal aligning agent (2).

[0216] <Example 3>

[0217] Into a 20 ml sample tube containing a stirrer, 3.00 g of the polyimide solution (A-1-PI) and 3.60 g of the polyamic acid solution (B-3) were weighed, and further 0.63 g of NMP, 3.60 g of GBL, 3.0 g of BCS, 0.90 g of a GBL solution containing 1 wt % of S-1, 0.027 g of C-2, and 0.27 g of an NMP solution containing 10 wt % of C-1 were added, and the mixture was stirred for 30 minutes using a magnetic stirrer to obtain a liquid crystal aligning agent (3).

[0218] <Example 4>

[0219] Into a 20 ml sample tube containing a stirrer, 3.00 g of the polyimide solution (A-1-PI) and 3.60 g of the polyamic acid solution (B-3) were weighed, and further 0.45 g of NMP, 3.60 g of GBL, 3.0 g of BCS, 0.90 g of a GBL solution containing 1 wt % of S-1, 0.027 g of C-2, and 0.45 g of an NMP solution containing 10 wt % of C-1 were added, and stirred for 30 minutes using a magnetic stirrer to obtain a liquid crystal aligning agent (4).

[0220] The points of the liquid crystal aligning agents obtained in Examples 1 to 4 and Comparative Example 1 are shown in Table 2 below.

[0221] [Table 2]

[0222]

[0223] The values ​​in brackets in Table 2 indicate the proportion (parts by mass) of each polymer component or additive relative to 100 parts by mass of the total polymer components used to prepare the liquid crystal aligning agent for polymers and additives, respectively. The values ​​in brackets in Table 2 indicate the proportion (parts by mass) of each organic solvent relative to 100 parts by mass of the total organic solvent used to prepare the liquid crystal aligning agent for organic solvents.

[0224] <Production of Liquid Crystal Display Devices>

[0225] A substrate with electrodes is prepared. The substrate is 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 IZO electrode with a dense pattern constituting a counter electrode is formed. On the counter electrode of the first layer, as the second layer, a SiN (silicon nitride) film formed by a CVD method is formed. The film thickness of the second layer SiN film is 500 nm, and it functions as an interlayer insulating film. On the second layer SiN film, as the third layer, a comb-shaped pixel electrode formed by patterning the IZO film is arranged to form two types of pixels, the first pixel and the second pixel. The size of each pixel is 10 mm in length and about 5 mm in width. 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 second layer SiN film.

[0226] 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 "<" with the central portion bent at an internal angle of 160°. 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 "<" with the central portion bent, so the shape of each pixel is not a rectangular shape, but has a shape similar to a bold "<" 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.

[0227] In addition, unlike the above-mentioned glass substrate with electrodes (hereinafter also referred to as the first glass substrate), a second glass substrate having a columnar spacer with a height of 3.5 μm on the surface and an ITO film for anti-static treatment formed on the back is prepared to produce a group of liquid crystal units.

[0228] The liquid crystal alignment agent filtered through a filter with an aperture of 1.0 μm was applied to the surface of each of the above-mentioned glass substrates by spin coating, and dried on a heating plate at 80°C for 2 minutes. Then, a prescribed amount of ultraviolet rays with a wavelength of 254 nm polarized along a linear direction with an extinction ratio of 26:1 were irradiated to the coating surface through a polarizing plate, and then calcined in a hot air circulation oven at 230°C for 30 minutes to obtain a substrate with a liquid crystal alignment film with a film thickness of 100 nm. It should be noted that the liquid crystal alignment film formed on the first glass substrate is oriented in a manner that the direction that divides the inner angle of the pixel bending part into equal parts is orthogonal to the orientation direction of the liquid crystal, and the liquid crystal alignment film formed on the second glass substrate is oriented in a manner that the orientation direction of the liquid crystal on the first substrate is consistent with the orientation direction of the liquid crystal on the second substrate when making a liquid crystal unit.

[0229] Next, a sealant was printed on one side of the glass substrate with a liquid crystal alignment film in the above group, and the other substrate was laminated in a manner facing the liquid crystal alignment film surface, and the sealant was cured to produce an empty cell. Liquid crystal MLC-3019 (Merck) was injected into the empty cell by a reduced pressure injection method, and the injection port was sealed to obtain an FFS driven liquid crystal cell. Then, the obtained liquid crystal cell was heated at 120°C for 1 hour and left overnight for evaluation.

[0230] [evaluate]

[0231] <Contrast uniformity within the plane>

[0232] The twist angle of the liquid crystal display element was evaluated using SYMTEC's OPTIPRO-micro. The produced liquid crystal display element was placed on a measuring table, and 20 points were measured in the first pixel plane without applying voltage, and the standard deviation was calculated. For evaluation, the case where the twist angle standard deviation was 0.4 or more was considered "poor", and the case where it was less than 0.4 was considered "good".

[0233] <Evaluation of Liquid Crystal Orientation Stability>

[0234] The liquid crystal display element used for the evaluation was used to apply an AC voltage of 10 VPP at a frequency of 30 Hz for 168 hours in a constant temperature environment of 60° C. Then, the pixel electrode and the counter electrode of the liquid crystal display element were short-circuited and left at room temperature for one day.

[0235] After placement, the liquid crystal display element is set between two polarizing plates configured in a manner orthogonal to the polarization axis, the backlight is turned on without applying voltage, and the configuration angle of the liquid crystal display element is adjusted to minimize the brightness of the transmitted light. Then, the rotation angle when the liquid crystal display element is rotated from the darkest angle of the second area of ​​the first pixel to the darkest angle of the first area is calculated as the angle Δ. Similarly in the second pixel, the second area is compared with the first area to calculate the same angle Δ. Then, the average value of the angle Δ values ​​of the first pixel and the second pixel is calculated as the angle Δ of the liquid crystal display element. When the value of the angle Δ of the liquid crystal display element exceeds 0.1 degrees, it is evaluated as "poor". When the value of the angle Δ of the liquid crystal unit does not exceed 0.1 degrees, it is evaluated as "good".

[0236] <Evaluation of the relaxation characteristics of stored charge>

[0237] Afterimages were evaluated using the following optical system, etc. The produced liquid crystal display element was placed between two polarizing plates arranged with their polarization axes orthogonal to each other, the LED backlight was turned on without applying voltage, and the arrangement angle of the liquid crystal display element was adjusted to minimize the brightness of the transmitted light.

[0238] Next, while applying an AC voltage with a frequency of 30 Hz to the liquid crystal display element, a VT curve (voltage-transmittance curve) was measured, and an AC voltage at which the relative transmittance became 23% was calculated as a driving voltage.

[0239] In the afterimage evaluation, the liquid crystal display element was driven by applying an AC voltage of 30 Hz at a relative transmittance of 23% and applying a DC voltage of 1 V for 40 minutes. Then, the DC voltage value was set to 0 V, and only the DC voltage was stopped, and the element was driven for another 15 minutes in this state.

[0240] The evaluation was “good” when the relative transmittance dropped to 27% or less within 45 minutes from the start of the DC voltage application. The evaluation was “poor” when it took more than 45 minutes for the relative transmittance to drop to 27% or less.

[0241] Then, the afterimage evaluation according to the above method was performed under the temperature condition that the temperature of the liquid crystal display element was 23°C.

[0242] <Evaluation of sealing tightness>

[0243] [Sample production]

[0244] The liquid crystal orientation agent prepared above was applied to a 30mm×40mm ITO substrate by spin coating. After drying on a hot plate at 80°C for 2 minutes, the coating surface was irradiated with 254nm ultraviolet rays through a polarizing plate, and then sintered in a hot air circulation oven at 230°C for 20 minutes to form a coating with a thickness of 100nm. The two substrates obtained in this way were prepared, and after a bead-shaped spacer with a diameter of 4μm was applied to the liquid crystal orientation film surface of one substrate, a sealant (XN-1500T manufactured by Kyoritsu Chemical) was dripped. Then, the liquid crystal orientation film surface of the other substrate was set to the inner side, and the substrates were bonded in such a way that the overlapping width became 1cm. At this time, the amount of sealant added was adjusted so that the diameter of the sealant after bonding became 3mm. After fixing the two bonded substrates with a clamp, they were thermally cured at 150°C for 1 hour to produce a sample for evaluating adhesion.

[0245] [Measurement of Adhesion]

[0246] The sample substrates prepared above were fixed with a table-top precision universal testing machine (manufactured by Shimadzu Corporation, AGS-X500N) to the ends of the upper and lower substrates. Then, the substrates were pressed from the upper center to measure the peeling strength (N). The peeling strength (N) was divided by the bonding area (mm 2 ) was set as the sealing tightness (N / mm 2), at 5N / mm 2 If the load is larger, it is evaluated as "good". 2 In the case of , the evaluation is "poor".

[0247] The evaluation results of each liquid crystal display element of Examples 1 to 4 and Comparative Example 1 are shown in Table 3 below.

[0248] [Table 3]

[0249]

[0250] Industrial Applicability

[0251] 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 IPS drive system and FFS drive system.

[0252] It should be noted that all the contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2018-227376 filed on December 4, 2018 are incorporated herein by reference and incorporated as a disclosure of the specification of the present invention.

Claims

1. A liquid crystal alignment agent, characterized in that: Contains the following components A and B, Component A: a polymer A having a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2), Component B: a polymer B having a repeating unit represented by the following formula (8) and a repeating unit represented by the following formula (9), In the formula, R1 to R4 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group, at least one of R1 to R4 represents a group other than a hydrogen atom in the above definition, and Y1 represents a divalent organic group having a partial structure represented by the following formula (H), In the formula, Q 3 For -(CH2) n -, wherein n is an integer of 2 to 20, any -CH2- is optionally substituted by -O-, but the oxygen atoms are not directly bonded to each other, any hydrogen atoms on the two benzene rings are optionally substituted by a monovalent organic group, and * represents a bonding bond, In the formula, X2 represents a tetravalent organic group having an alicyclic structure of five or more members, and Y2 represents a divalent organic group having a partial structure represented by the formula (H). In the formula, X8 is a tetravalent organic group having an alicyclic structure of five or more rings, X9 represents a tetravalent organic group derived from an aromatic acid dianhydride, Y8 is a divalent organic group having a partial structure represented by the following formula (m), * is a bonding bond, Y9 is a divalent organic group having a partial structure represented by the following formula (n-1) or (n-2), and Z 81 , Z 82 , Z 91 , Z 92 each independently represents a hydrogen atom, 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, R8 and R9 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, Q1 and Q2 represent a hydrogen atom or a methyl group, 2. The liquid crystal alignment agent according to claim 1, wherein The polymer A contains 1 to 95 mol% of the total amount of the repeating unit represented by the formula (1) and the repeating unit represented by the formula (2) based on all the repeating units.

3. The liquid crystal aligning agent according to claim 1 or 2, wherein: The polymer B contains 50 to 100 mol % of the repeating unit represented by the formula (8) and the repeating unit represented by the formula (9) based on all the repeating units of the polymer B.

4. The liquid crystal aligning agent according to claim 1 or 2, wherein X2 in the formula (2) is independently a tetravalent organic group represented by any one of the following formulas (X2-1) to (X2-12), 5. The liquid crystal aligning agent according to claim 1 or 2, wherein In the formula (1) and the formula (2), Y1 and Y2 are each independently a divalent organic group having a partial structure represented by any one of the following formulas (H-1) to (H-6), 6. The liquid crystal aligning agent according to claim 1 or 2, wherein: In the formula (1) and the formula (2), Y1 and Y2 are each independently a divalent organic group represented by any one of the following formulas (h-1) to (h-7), 7. The liquid crystal aligning agent according to claim 1 or 2, wherein: The polymer A further comprises 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), In the formula, R 41 ~R 44 are synonymous with R1 to R4 of the formula (1), Y4 and Y5 represent a divalent organic group represented by the following formula (I), and X5 is synonymous with X2 of the formula (2). In the formula, Q represents a single bond or an oxygen atom, n represents 0 to 2, and any hydrogen atom on the benzene ring may be optionally substituted by a monovalent organic group.

8. The liquid crystal alignment agent according to claim 7, wherein: Y4 in the formula (4) and Y5 in the formula (5) are divalent organic groups represented by any one of the following formulas (I-1) to (I-3), In the formula, * represents a bonding bond.

9. The liquid crystal alignment agent according to claim 1 or 2, wherein: The polymer A further comprises at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (6) and a repeating unit represented by the following formula (7), In the formula, R 61 To R 64 are synonymous with R1 to R4 of the above formula (1), Y6 and Y7 are independently a divalent organic group having a partial structure represented by the following formula (J-1) or a divalent organic group represented by the following formula (J-2), X7 is synonymous with X2 of the above formula (2), In the formula, Q5 is a single bond, -(CH2) n -, or -(CH2) n Any -CH2- in - is replaced by -O-, -COO-, -OCO-, -NQ9-, -NQ9CO-, -CONQ9-, -NQ9CONQ 10 -, -NQ9COO-, -OCOO-substituted group, n is an integer of 1 to 20, Q9 and Q 10 Each independently represents a hydrogen atom or a monovalent organic group; Q6 and Q7 independently represent -H, -NHD, -N(D)2, a group having -NHD, and a group having -N(D)2, respectively; Q8 represents -NHD, -N(D)2, a group having -NHD, and a group having -N(D)2; D represents a carbamate-based protecting group; at least one of Q5, Q6 and Q7 has a carbamate-based protecting group in the group; and *1 represents a bonding bond.

10. The liquid crystal alignment agent according to claim 9, wherein: The partial structure represented by the formula (J-1) is a partial structure represented by any one of the following formulas (J-1-a) to (J-1-d), 11. The liquid crystal alignment agent according to claim 1 or 2, wherein X9 in the formula (9) is selected from the following formulas (X3-1) to (X3-2), In the formula, x and y are each independently a single bond, an ether bond, a carbonyl group, an ester bond, an alkanediyl group having 1 to 5 carbon atoms, a 1,4-phenylene group, a sulfonyl group or an amide group, j and k are each independently 0 or 1, and * represents a bond.

12. The liquid crystal alignment agent according to claim 1 or 2, wherein: Y8 in the formula (8) is a divalent organic group represented by (Y3-1) or (Y3-2), 13. The liquid crystal aligning 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 weight ratio of polymer A / polymer B. 14 . A liquid crystal alignment film obtained from the liquid crystal aligning agent according to claim 1 . 15 . A liquid crystal display element comprising the liquid crystal alignment film according to claim 14 .

16. A method for manufacturing a liquid crystal alignment film, wherein: The method comprises the following steps A to C: Step A is a step of applying the liquid crystal aligning agent according to any one of claims 1 to 13 onto a substrate. Step B is a step of heating the coating film of the liquid crystal aligning agent obtained in step A to obtain a film. Step C is a step of irradiating the film obtained in step B with polarized ultraviolet rays.

17. The method for manufacturing a liquid crystal alignment film according to claim 16, wherein: It also includes the following step D, Step D is a step of firing the film obtained in step C at a temperature higher than that in step B and not lower than 100°C.

18. The method for producing a liquid crystal alignment film according to claim 16 or 17, wherein: In the step B, the coating film is heated within a temperature range of 40 to 180°C. 19 . A liquid crystal display element comprising a liquid crystal alignment film obtained by the method for producing a liquid crystal alignment film according to claim 16 .

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