WO2020116459A1 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

Provided are: a liquid crystal alignment film that exhibits good resistance to AC image persistence or residual DC-derived image persistence, and has good adhesion to a sealing agent; and a liquid crystal alignment agent that can be used to obtain a liquid crystal display element which inhibits in-plane variations in brightness during black displaying, and has excellent contrast characteristics. This liquid crystal alignment agent is characterized by containing component (A) and component (B). Component (A): a polymer (A) having a repeating unit represented by formula (1). Component (B): a polymer (B) having a repeating unit represented by formula (3). (In formula (1), R₁-R₄ each represent a hydrogen atom, a halogen atom, an alkyl group having 1-6 carbon atoms, or the like, at least one of R₁-R₄ is a group as defined above but, excluding a hydrogen atom. Y₁ represents a divalent organic group having a moiety structure represented by formula (H). In formula (3), X₃ represents a tetravalent organic group derived from an aromatic acid dianhydride, Y₃ represents a divalent organic group having a moiety structure represented by formula (m). R₃₀ represents a hydrogen atom or an alkyl group having 1-4 carbon atoms. Z₃₁ and Z₃₂ each represent a hydrogen atom or the like.) (Q³ represents -(CH₂)_n- (n is 2-20), any -CH₂- may be substituted by -O-. Note that oxygen atoms are not directly bonded together. Any hydrogen atom on the benzene ring may be substituted by a monovalent organic group. * represents a bond.)

Description

Liquid crystal aligning agent, liquid crystal aligning film and liquid crystal display device

The present invention relates to a liquid crystal aligning agent, a liquid crystal aligning film, and a liquid crystal display device using the same.

Conventionally, liquid crystal devices have been widely used as display units for personal computers, smartphones, mobile phones, televisions, and the like. The liquid crystal device includes, for example, a liquid crystal layer sandwiched between an element substrate and a color filter substrate, a pixel electrode and a common electrode that apply an electric field to the liquid crystal layer, an alignment film that controls the alignment of liquid crystal molecules in the liquid crystal layer, and a pixel. A thin film transistor (TFT) for switching an electric signal supplied to the electrode is provided. Known driving methods of liquid crystal molecules include a vertical electric field method such as a TN method and a VA method, and a lateral electric field method such as an IPS method and a fringe field switching (hereinafter, FFS) method.

At present, the most widely used liquid crystal alignment film in the industry is to coat the surface of a film made of polyamic acid and/or polyimide imidized on an electrode substrate with a cloth such as cotton, nylon or polyester. It is manufactured by rubbing in one direction, that is, a so-called rubbing treatment. The rubbing treatment is an industrially useful method that is simple and excellent in productivity. However, due to the high performance, high definition, and large size of liquid crystal display elements, scratches on the surface of the alignment film generated by rubbing treatment, dust generation, the influence of mechanical force and static electricity, Various problems such as non-uniformity have become clear. As a liquid crystal alignment treatment method that replaces the rubbing treatment, a photoalignment method is known, which imparts liquid crystal alignment ability by irradiating polarized radiation. As the liquid crystal alignment treatment by the photo-alignment method, a method utilizing a photoisomerization reaction, a method utilizing a photocrosslinking reaction, a method utilizing a photodecomposition reaction, etc. have been proposed (see Non-Patent Document 1 and Patent Document 1). ..

The liquid crystal alignment film, which is a component of the liquid crystal display element, is a film for uniformly aligning the liquid crystals, but various characteristics are required in addition to the alignment uniformity of the liquid crystals. For example, charges are accumulated in the liquid crystal alignment film due to the voltage for driving the liquid crystal, and the display is affected as an afterimage or image sticking (hereinafter referred to as an afterimage due to residual DC), which significantly deteriorates the display quality of the liquid crystal display element. Therefore, a liquid crystal aligning agent that overcomes these problems has been proposed (see Patent Document 2).

Also, in the IPS method and FFS driving method, the stability of liquid crystal alignment is also important. If the alignment stability is low, the liquid crystal will not return to the initial state when the liquid crystal is driven for a long time, which may cause a decrease in contrast and burn-in (hereinafter referred to as AC afterimage). As a method for solving the above problems, Patent Document 3 discloses a specific liquid crystal aligning agent.

Furthermore, with the spread of tablets and smartphones, the development of liquid crystal display elements with a narrow frame that secures the display area as wide as possible is underway. Due to this narrowing of the frame, it has become necessary to apply a sealant on the liquid crystal alignment film. Therefore, Patent Document 4 discloses a liquid crystal aligning agent having good adhesiveness with the sealant while maintaining the liquid crystal alignment. There is.

Japanese Unexamined Patent Publication No. 9-297313 International Publication No. 2005/083504 Pamphlet International Publication No. 2015/050135 Pamphlet International Publication No. 2015/060360 Pamphlet

However, in an actual liquid crystal display element, the twist angle slightly varies within the surface of the liquid crystal display element due to manufacturing variations and the like. Then, due to such in-plane variation, the brightness at the time of black display in the liquid crystal display element varies in the plane. Further, the demand for higher definition for liquid crystal display elements is further increasing, and it is becoming more important than ever to exhibit good display quality.
The present invention has been made in view of the above circumstances, and exhibits good resistance to an afterimage of AC or an afterimage of residual DC and exhibits good adhesion with a sealant, and a liquid crystal alignment film and black display. An object of the present invention is to provide a liquid crystal aligning agent capable of obtaining a liquid crystal display device having excellent contrast characteristics, in which variation in brightness within the plane is suppressed.

As a result of intensive research, the present inventor has found that the above problem can be solved by using a liquid crystal aligning agent containing a specific component, and has completed the present invention. Specifically, the following is the summary.

A liquid crystal aligning agent comprising the following component (A) and component (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).

(R ₁ to R ₄ each independently contain 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, or a fluorine atom. Which is a monovalent organic group having 1 to 6 carbon atoms or a phenyl group, and at least one of R ₁ to R ₄ represents a group other than a hydrogen atom in the above definition, and Y ₁ is represented by the following formula (H): It represents a divalent organic group having a partial structure represented.)

(Q ³ is a structure represented by —(CH ₂ ) _n — (provided that n is an integer of 2 to 20 and arbitrary —CH ₂ — may be replaced with —O—. (Oxygen atoms are not directly bonded to each other.) Any hydrogen atom on the two benzene rings may be replaced with a monovalent organic group. * represents a bond.)

(X ₃ represents a tetravalent organic group derived from an aromatic acid dianhydride, Y ₃ represents a divalent organic group having a partial structure represented by the following formula (m), and * represents a bond. R ₃₀ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; Z ₃₁ and Z ₃₂ are each 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, Represents.)

According to the liquid crystal aligning agent of the present invention, it is possible to obtain a liquid crystal aligning film having good adhesion to the sealant. Further, it is possible to obtain a liquid crystal display element which is less likely to cause an afterimage due to residual DC and an AC afterimage, and has excellent contrast in which variation in brightness in a plane during black display is suppressed.

<Polymer (A)>
The liquid crystal aligning agent of the present invention contains a polymer (A) having a repeating unit represented by the above formula (1). With such a structure, a liquid crystal alignment film with less generation of AC afterimage can be obtained, and a liquid crystal display device with excellent contrast can be obtained. In the above formula (1), X ₂ , Y ₁ , Y ₂ , R ₁ , R ₂ , R ₃ and R ₄ are as defined above.

The tetravalent organic group represented by X _{2 in} the formula (1) is preferably a tetravalent organic group having a 5- to 8-membered alicyclic structure, and a 4-valent alicyclic structure having a 5- to 7-membered alicyclic structure. More preferably, it is a valent organic group. In addition, when the alicyclic structure to which the imide group is bonded is a polycyclic structure, the alicyclic structure having five or more membered rings means the number of atoms constituting the ring in each ring included in the polycyclic structure. Indicates that all are 5 or more. The alicyclic structure may be bonded to at least one of the two imide groups, and may have a chain hydrocarbon structure or an aromatic ring structure together with the alicyclic structure.

Specific examples of the alkyl group having 1 to 6 carbon atoms in R ₁ to R ₄ include methyl group, ethyl group, propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, Examples thereof include t-butyl group and n-pentyl group. Specific examples of the alkenyl group having 2 to 6 carbon atoms in R ₁ to R ₄ include a vinyl group, a propenyl group, a butynyl group and the like, which may be linear or branched. Specific examples of the alkynyl group having 2 to 6 carbon atoms in R ₁ to R ₄ include ethynyl group, 1-propynyl group, 2-propynyl group and the like. Examples of the halogen atom in R ₁ to R ₄ include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. Examples of the monovalent organic group containing a fluorine atom having 1 to 6 carbon atoms include a fluoromethyl group and a trifluoromethyl group. From the viewpoint of high photoreactivity, R ₁ to R ₄ are each a hydrogen atom or a methyl group, and at least one of R ₁ to R ₄ is preferably a methyl group, and more preferably at least one of R ₁ to R ₄ . Two is preferably a methyl group. More preferred is when R ₁ and R ₃ are methyl groups and R ₂ and R ₄ are hydrogen atoms.

Specific examples of the monovalent organic group in the formula (H) include 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, and a fluorine atom. Examples thereof include monovalent organic groups having 1 to 6 carbon atoms, and examples thereof include the structures exemplified for R ₁ to R ₄ . As the partial structure represented by the formula (H), a partial structure represented by any of the following formulas (H-1) to (H-6) can be mentioned from the viewpoint of less generation of AC afterimage.

As a preferred specific example of Y ₁ in the above formula (1), a divalent organic group represented by any of the following formulas (h-1) to (h-7) is preferable from the viewpoint of less generation of an AC afterimage. Can be mentioned.

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

(In the formula, X ₂ is a tetravalent organic group having a 5- or more-membered alicyclic structure. Y ₂ is a divalent organic group having a partial structure represented by the above formula (H). )

The tetravalent organic group represented by X _{2 in} the formula (2) is preferably a tetravalent organic group having a 5- to 8-membered alicyclic structure and 4 having a 5- to 7-membered alicyclic structure. More preferably, it is a valent organic group. In addition, when the alicyclic structure to which the imide group is bonded is a polycyclic structure, the alicyclic structure having five or more membered rings means the number of atoms constituting the ring in each ring included in the polycyclic structure. Indicates that all are 5 or more. The alicyclic structure may be bonded to at least one of the two imide groups, and may have a chain hydrocarbon structure or an aromatic ring structure together with the alicyclic structure.

Specific preferred examples of X ₂ include tetravalent organic groups represented by any of the following formulas (X2-1) to (X2-12).

(X2-1) to (X2-4) are more preferable from the viewpoint of less occurrence of AC afterimage and enhancing the contrast of the liquid crystal display element.

Specific preferred examples of Y ₂ in the above formula (2) are the same as the preferred specific examples of Y ₁ in the above formula (1).

The polymer (A) is at least one 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), from the viewpoint of enhancing the contrast of a liquid crystal display device. It may further have a repeating unit of.

R ₄₁ to R ₄₄ in the formulas (4) and (5) have the same meanings as R ₁ to R _{4 in} the formula (1), including preferred specific examples. X ₅ in formula (5) has the same meaning as X _{2 in} formula (2). Y ₄ and Y ₅ represent a divalent organic group represented by the following formula (I).

In the above 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 replaced with a monovalent organic group, and as such a monovalent organic group, the structures exemplified in the specific examples of the monovalent organic group in the above formula (H) can be used. Is mentioned.

2 _{Y 5} of the formula _{Y 4} and the formula (4) (5), from the viewpoint of enhancing the contrast of the liquid crystal display device, which is represented by any one of the following formulas (I-1) ~ (I -3) It is preferably a valent organic group. In the following formula, * represents a bond.

The polymer (A) is at least 1 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), from the viewpoint of enhancing the adhesiveness with a sealant. You may further have a repeating unit of a kind.

(In the formula, R ₆₁ to R ₆₄ have the same meanings as R ₁ to R _{4 in} the formula (1) including preferable specific examples, and Y ₆ and Y ₇ are independently the following formula (J-1). divalent organic groups having a partial structure represented in, or the following formula (J-2) X ₇ in. equation (7) represents a divalent organic group represented by X ₂ in the formula (2) Is synonymous with.)

In the formulas (J-1) and (J-2), Q ₅ is a single bond, —(CH ₂ ) _n — (n is an integer of 1 to 20) or —(CH ₂ ) _n —. , - _- -O under conditions which are not adjacent each - -CH ₂ of _{COO -, - OCO -, -} NQ 9 -, - NQ 9 CO -, - CONQ 9 -, - NQ 9 CONQ 10 -, - NQ 9 COO- and -OCOO- are substituted groups, and Q ₉ and Q ₁₀ each independently represent a hydrogen atom or a monovalent organic group;
Q ₆ and Q ₇ each independently represent a group having —H, —NHD, —N(D) ₂ , —NHD, or a group having —N(D) ₂ . Q ₈ represents a group having —NHD, —N(D) ₂ , and —NHD, and a group having —N(D) ₂ . D represents a carbamate-based protecting group, and examples of the carbamate-based protecting group include a tert-butoxycarbonyl group and a 9-fluorenylmethoxycarbonyl group. However, at least one of Q ₅ , Q ₆ and Q ₇ has a carbamate-based protecting group in the group. *1 represents a bond. Preferred specific examples of Y ₆ and Y ₇ are 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. And a divalent organic group. “Boc” represents a tert-butoxycarbonyl group.

The polymer (A) is represented by 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), and the above formula (5). In addition to the repeating unit represented by the formula (6) and the repeating unit represented by the formula (7), the repeating unit represented by the formula (PI-A-1) and (PA) It may have at least a repeating unit selected from the group consisting of repeating units represented by -1).

In formula (PI-A-1), X _I1 represents a tetravalent organic group, and Y _I1 represents a divalent organic group. However, when X _I1 has the same meaning as a tetravalent organic group represented by the following formula (g) or X _{2 in the} above formula (2), Y _I1 represents a partial structure represented by the above formula (H). A divalent organic group having, a divalent organic group represented by the formula (I), a divalent organic group having a partial structure represented by the formula (J-1), the formula (J-2) Represents a structure other than the divalent organic group represented by. Examples of X _I1 include a tetravalent organic group represented by the following formula (g), a tetravalent organic group exemplified as X ₂ in the above formula (2), and the following formulas (X _I1 −1) to (X _{And a} tetravalent organic group represented by any one of I1-13) and a tetravalent organic group derived from an aromatic tetracarboxylic dianhydride.

_{(R 1, R 2, R 3} , R 4 have the same meaning as _{R 1, R 2, R 3} , R 4 in the formula (1).)

Here, the aromatic tetracarboxylic dianhydride is 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). The tetravalent organic group can be mentioned.

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

In formula (PI-A-1), specific examples of the divalent organic group represented by Y _I1 include a divalent organic group having a partial structure represented by formula (H), and a divalent organic group represented by formula (I). In addition to the divalent organic group represented by the formula (J-1), the divalent organic group having a partial structure represented by the formula (J-1), the divalent organic group represented by the formula (J-2), Divalent organic groups represented by (o-1) to (o-23), groups represented by any of the formulas (Y-1) to (Y-167) described in International Publication No. 2018/117239. Etc.

In formula (PA-1), X _A1 represents a tetravalent organic group, and Y _A1 represents a divalent organic group. Specific examples of X _A1 include the structures exemplified by X _I1 of the above formula (PI-A-1), and specific examples of Y _A1 include Y _I1 of the above formula (PI-A-1). The structure can be mentioned.

In formula (PA-1), R _A1 represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; Z _A11 and Z _A12 each independently represent a hydrogen atom or a C ₁ to C ₁ which may have a substituent. 10-alkyl group, optionally substituted C2-C10 alkenyl group, optionally substituted C2-C10 alkynyl group, tert-butoxycarbonyl group, or 9-fluorene It is a nylmethoxycarbonyl group.

Specific examples of the alkyl group having 1 to 5 carbon atoms of R _A1 include methyl group, ethyl group, propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl group. Group, n-pentyl group and the like. From the viewpoint of ease of imidization by heating, R ₁ is preferably a hydrogen atom or a methyl group.

Specific examples of the alkyl group having 1 to 10 carbon atoms of Z _A11 and Z _A12 include, in addition to the specific examples of the alkyl group having 1 to 5 carbon atoms exemplified for R ₁ , a hexyl group, a heptyl group, an octyl group. , Nonyl group, decyl group and the like. Specific examples of the alkenyl group having 2 to 10 carbon atoms of Z _A11 and Z _A12 include a vinyl group, a propenyl group, a butynyl group and the like, and these may be linear or branched. Specific examples of the alkynyl group having 2 to 10 carbon atoms of Z _A11 and Z _A12 include ethynyl group, 1-propynyl group, 2-propynyl group and the like.

Z _A11 and Z _A12 may have a substituent, and examples of the substituent include a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), a hydroxyl group, a cyano group, an alkoxy group and the like. Be done.

From the viewpoint of less AC afterimage, the polymer (A) has a repeating unit represented by the above formula (1) and a repeating unit represented by the above formula (2) in an amount of 1 to 95 mol% of all repeating units. It is preferable to include.

<Polymer (B)>
The liquid crystal aligning agent of the present invention contains a polymer (B) having a repeating unit represented by the above formula (3). With such a configuration, the heat resistance of the obtained liquid crystal alignment film can be enhanced, so that a liquid crystal alignment film with less AC afterimage can be obtained and variation in twist angle in the plane that occurs during manufacturing can be suppressed. Thus, a liquid crystal display device having excellent contrast can be obtained. In the above formula (3), X ₃ , Y ₃ , R ₃₀ , Z ₃₁ , and Z ₃₂ are as defined above.

Specific examples of the alkyl group having 1 to 5 carbon atoms for R ₃₀ include the structures exemplified for R _A1 in the formula (PA-1). From the viewpoint of easiness of imidization by heating, it is preferable that each R ₃₀ is independently a hydrogen atom or a methyl group.

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 of Z ₃₁ and Z ₃₂ include Z _{A1 of} the above formula (PA-1), The structure etc. which were illustrated by _ZA2 are mentioned.

Z ₃₁ and Z ₃₂ may have a substituent, and examples of the substituent include the structures exemplified as Z _A1 and Z _A2 in the above formula (PA-1).

From the viewpoint of less AC afterimage, Z ₃₁ and Z ₃₂ are preferably each independently a hydrogen atom or a methyl group.

As Y _{3 in the} formula (3), a divalent organic group selected from the following formulas (Y3-1) to (Y3-2) may be used from the viewpoint of less AC afterimage.

Specific examples of the aromatic dianhydride in X ₃ of the above formula (3) include the structures exemplified in the above X _I1 . X ₃ is preferably a tetravalent organic group represented by the above formula (X3-1) or (X3-2), from the viewpoint of less AC afterimage. As the tetravalent organic group represented by the above formula (X3-1) or (X3-2), more preferable specific examples are the structures represented by any of the following formulas (X3-3) to (X3-19). Is mentioned.

The polymer (B) is represented by the repeating unit represented by the following formula (8) and the following formula (9) from the viewpoint of enhancing the seal adhesion of the liquid crystal alignment film and reducing the residual image derived from residual DC. It may have at least one type of repeating unit selected from the group consisting of repeating units.

(In the formula, X ₈ is a tetravalent organic group having an alicyclic structure having 5 or more membered rings, and has the same meaning as X _{2 in the} above formula (2) including a preferred embodiment. X ₉ is a 5 or more membered ring. Which is a tetravalent organic group having an alicyclic structure or a tetravalent organic group derived from an aromatic acid dianhydride, and is a preferred embodiment with X _{2 of the} formula (2) or X _{3 of the} formula (3). Y ₈ has the same meaning as Y _{3 in the} above formula (3), and Y ₉ represents a divalent organic compound having a partial structure represented by the following formula (n-1) or (n-2). Z ₈₁ , Z ₈₂ , Z ₉₁ , and Z ₉₂ have the same meanings as Z ₃₁ and Z ₃₂ of the formula (3), respectively, and R ₈ and R ₉ each independently represent a hydrogen atom or a carbon number of 1. Are alkyl groups of 4 to 4, and Q ₁ and Q ₂ each independently represent a hydrogen atom or a methyl group.)

Specific examples of the divalent organic group having the partial structure represented by the above formula (n-1) or (n-2) include, for example, the following formulas (ND-1-2) and (ND-2-1). The structure represented by any one of to (ND-2-3) and (ND-5) is mentioned.

(R ²¹ and R ²² each independently represent a hydrogen atom or a methyl group, Q ²² independently represents a single bond, or *1-R ²³ -Ph-*2, R ²³ represents a single bond, -O Represents a divalent organic group selected from —, —COO—, —OCO—, —(CH ₂ ) _l —, —O(CH ₂ ) _m O—, —CONH—, and —NHCO— (l, m Represents an integer of 1 to 5), *1 represents a site bonded to a benzene ring in formula (ND-1-2), and *2 bonds to an amino group in formula (ND-1-2). Represents a moiety, Ph represents a phenylene group, and n represents an integer of 1 to 3.)

In the formula, R ²¹ and R ²² are each a hydrogen atom or a methyl group. R ^24's each independently represent a single bond or the structure of formula (Ar) below, and n represents an integer of 1 to 3. * Represents a bond. Further, 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.).

In the formula, R ²⁵ is selected from a single bond, —O—, —COO—, —OCO—, —(CH ₂ ) _l —, —O(CH ₂ ) _m O—, —CONR—, and —NRCO—. Represents a divalent organic group, and k represents an integer of 1 to 5. In addition, R represents hydrogen or a monovalent organic group such as 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 bonds to the benzene ring in formulas (ND-2-1) to (ND-2-3).

(R ⁵¹ and R ⁵² each independently represent a hydrogen atom or a methyl group. A ₅ is a single bond or a divalent group such as —O—, —(CH ₂ ) _n — (n is an integer of 1 to 4). Represents the organic group of.)

Specific preferred examples of the formula (ND-1-2) include structures represented by any of the following formulas (n1-9) to (n1-14).

Preferred specific examples of the formulas (ND-2-1) to (ND-2-3) include structures represented by any of the following formulas (n2-1) to (n2-6).

Preferred specific examples of the formula (ND-5) include structures represented by any of the following formulas (n5-1) to (n5-8).

The polymer (B) has the following formula (PA-) 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). It may have a repeating unit represented by 2).

In formula (PA-2), X _A2 represents a tetravalent organic group, and Y _A2 represents a divalent organic group. _However, if the _{X A2} is the same meaning as _{X 9} in formula _{(9), Y A2} is the bivalent organic group or the above formula having a partial structure represented by formula (m) (n-1) or It represents a structure other than the divalent organic group having the partial structure represented by (n-2). R _A2 has the same meaning as R _{3 of the} formula (3) including preferred embodiments, and Z _A21 and Z _A22 have the same meaning as Z ₃₁ and Z ₃₂ of the formula (3) including preferred embodiments.

Specific examples of X _A2 include an aliphatic tetracarboxylic dianhydride and an alicyclic tetracarboxylic dianhydride, in addition to the aromatic tetracarboxylic dianhydride exemplified as X ₃ in the above formula (3). And a tetravalent organic group.
Specific examples of Y _A2 include a divalent organic group having a partial structure represented by the formula (m) or a divalent organic group having a partial structure represented by the formula (n-1) or (n-2). In addition to the organic groups described in WO2017/126627, the pyrrole structure described in WO2017/126627 is added to a divalent organic group, preferably a divalent organic group represented by the following formula (pr), in International Publication WO2018/092759. A divalent organic group having a thiophene or furan structure, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol , 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid or 3,5-diaminobenzoic acid, and a carboxyl group such as a diamine compound represented by the following formula [3b-1] to [3b-4] A divalent organic group obtained by removing two amino groups from a diamine, a divalent organic group having —NH—CO—NH— in the molecule of the following formulas (U-1) to (U-9), etc. Examples thereof include the divalent organic groups described in paragraphs [0013] to [0030] of Published Publication WO2018-181566.

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”, and R ⁸³ represents a single bond, Represents a divalent organic group selected from —O—, —COO—, —OCO—, —(CH ₂ ) _l —, —O(CH ₂ ) _m O—, —CONH—, and —NHCO— (l , M represents an integer 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 nitrogen atom in the formula (PA-2). .. Ph represents a phenylene group. n represents 1 to 3.

In formula [3b-1], A ¹ is a single bond, —CH ₂ —, —C ₂ H ₄ —, —C(CH ₃ ) ₂ —, —CF ₂ —, —C(CF ₃ ) ₂ —, — _{O -, - CO -, -} NH -, - N (CH 3) -, - CONH -, - NHCO -, - CH 2 O -, - OCH 2 -, - COO -, - OCO -, - CON (CH ₃ )- or N(CH ₃ )CO—, m ¹ and m ² each independently represents an integer of 0 to 4, and m ¹ +m ² represents an integer of 1 to 4 and is represented by the formula [3b -2], m ³ and m ⁴ each independently represent an integer of 1 to 5, and in the formula [3b-3], A ² represents a linear or branched alkylene group having 1 to 5 carbon atoms, m ⁵ represents an integer of 1 to 5, and in the formula [3b-4], A ³ and A ⁴ are each independently a single bond, —CH ₂ —, —C ₂ H ₄ —, or —C(CH ₃ ) ₂ —, —CF ₂ —, —C(CF ₃ ) ₂ —, —O—, —CO—, —NH—, —N(CH ₃ )—, —CONH—, —NHCO—, —CH ₂ O. Represents —, —OCH ₂ —, —COO—, —OCO—, —CON(CH ₃ )— or N(CH ₃ )CO—, and m ⁶ represents an integer of 1 to 4.

From the viewpoint of enhancing the contrast, the polymer (B) of the present invention preferably contains the repeating unit represented by the above formula (3) in an amount of 30 to 100 mol% based on all repeating units of the polymer (B). Alternatively, it is preferably 40 to 100 mol %, or preferably 50 to 100 mol %.

From the viewpoint of less afterimages due to AC and residual DC, the orientation ratio between the polymer (A) and the polymer (B) is 5/95 in terms of the polymer (A)/polymer (B) mass ratio. It is preferably from 95/5. From the viewpoint of obtaining a liquid crystal alignment film with high reproducibility, the alignment ratio of the polymer (A) and the polymer (B) is 10/in the mass ratio of polymer (A)/polymer (B). 90 to 90/10 is more preferable, and 20/80 to 80/20 is still more preferable.

<Method for producing polyamic acid, polyamic acid ester and polyimide>
The polyimide precursor polyamic acid ester, polyamic acid and polyimide used in the present invention can be synthesized by a known method as described in, for example, International Publication WO 2013/157586.

<Liquid crystal aligning agent>
The liquid crystal aligning agent of the present invention contains a polymer (A) and a polymer (B). The liquid crystal aligning agent of the present invention may contain other polymer in addition to the polymer (A) and the polymer (B). Other types of polymers include polyamic acid, polyimide, polyamic acid ester, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene or its derivative, poly(styrene-phenylmaleimide) derivative, poly(meth) ) Acrylate etc. can be mentioned.

The liquid crystal aligning agent is used for producing a liquid crystal aligning film, and takes the form of a coating liquid from the viewpoint of forming a uniform thin film. Also in the liquid crystal aligning agent of the present invention, a coating liquid containing the above-mentioned polymer component and an organic solvent is preferable. At that time, the concentration of the polymer in the liquid crystal aligning agent can be appropriately changed by setting the thickness of the coating film to be formed. From the viewpoint of forming a uniform and defect-free coating film, 1% by mass or more is preferable, and from the viewpoint of storage stability of the solution, 10% by mass or less is preferable. A particularly preferable polymer concentration is 2 to 8% by mass.

The organic solvent contained in the liquid crystal aligning agent is not particularly limited as long as the polymer component is uniformly dissolved therein. Specific examples thereof include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone and 1,3-dimethyl. -Imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide (collectively referred to as "good solvent"), etc. Can be mentioned. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide or γ-butyrolactone can be used. preferable. The good solvent in the liquid crystal aligning agent of the present invention is preferably 20 to 99% by mass, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass based on the whole solvent contained in the liquid crystal aligning agent. Is.

As the organic solvent contained in the liquid crystal aligning agent, a solvent (also referred to as a poor solvent) is used in addition to the solvent as described above, which improves the coating properties when applying the liquid crystal aligning agent and the surface smoothness of the coating film. It is preferable to use the mixed solvent described above. Specific examples of the organic solvent used in combination are shown below, but the invention is not limited to these examples.
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 monoisoamyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2- Propanol, 2-(2-butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, ethylene glycol mono Acetate, 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 acetate Glycol monoethyl ether, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, Examples thereof include diethylene glycol monoethyl ether and diisobutyl ketone (2,6-dimethyl-4-heptanone).

Among them, 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 is preferred.

Preferred solvent combinations of a good solvent and a poor solvent include N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and ethylene glycol monobutyl ether, and N-methyl-2-. Pyrrolidone, γ-butyrolactone and propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and 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 And propylene glycol monobutyl ether and dipropylene glycol dimethyl ether. The amount of the poor solvent is preferably 1 to 80% by mass, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass, based on the whole solvent contained in the liquid crystal aligning agent. The type and content of such a solvent are appropriately selected depending on the application device of the liquid crystal alignment agent, the application conditions, the application environment, and the like.

The liquid crystal aligning agent of the present invention may additionally contain components other than the polymer component and the organic solvent. Examples of such additional components include an adhesion aid for increasing the adhesion between the liquid crystal alignment film and the substrate and the adhesion between the liquid crystal alignment film and the sealing material, and a compound (crosslinking compound) for increasing the strength of the liquid crystal alignment film. Also referred to as a), a dielectric or a conductive substance for adjusting the dielectric constant or electric resistance of the liquid crystal alignment film.

The crosslinkable compound includes an oxiranyl group, an oxetanyl group, a protected isocyanate group, a protected isothiocyanate group, a group containing an oxazoline ring structure, and a Meldrum's acid structure, from the viewpoint of less generation of an AC afterimage and a high effect of improving film strength. A compound having a group, a cyclocarbonate group, a group represented by the following formula (d), or a compound represented by the following formula (e) (these are generically referred to as compound (C)) is preferable.

In formulas (d) and (e), R ₇₁ , R _72, and R ₇₃ are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or *—CH ₂ —OH. * Indicates a bond. A represents a (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.

Specific examples of the compound having an oxiranyl group include, for example, the compound described in paragraph [0037] of JP-A-10-338880 and the compound having a triazine ring in the skeleton described in WO2017/170483. And a compound having two or more oxiranyl groups. Of these, N,N,N',N',-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N', -Tetraglycidyl-4,4'-diaminodiphenylmethane, N,N,N',N'-tetraglycidyl-p-phenylenediamine, represented by any of the following formulas (r-1) to (r-3) Particularly preferred are compounds containing a nitrogen atom, such as compounds.

Specific examples of the compound having an oxetanyl group include, for example, the compounds having two or more oxetanyl groups described in paragraphs [0170] to [0175] of International Publication WO2011/132571.

Specific examples of the compound having a protected isocyanate group include, for example, compounds having two or more protected isocyanate groups described in paragraphs [0046] to [0047] of JP-A-2014-224978, International Publication WO 2015/ Examples thereof include the compounds having three or more protected isocyanate groups described in paragraphs [0119] to [0120] of No. 141598. Of these, compounds represented by any of the following formulas (bi-1) to (bi-3) are preferable.

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

Specific examples of the compound having a group containing an oxazoline ring structure include the compounds containing two or more oxazoline structures described in paragraph [0115] of JP-A-2007-2866597.

Specific examples of the compound having a group containing Meldrum's acid structure include compounds having two or more Meldrum's acid structures described in International Publication WO2012/091088.
Specific examples of the compound having a cyclocarbonate group include the compounds described in International Publication WO2011/155557.

Examples of the alkyl group having 1 to 3 carbon atoms which is R ₇₁ , R ₇₂ and R ₇₃ in the formula (d) include a methyl group, an ethyl group and a propyl group.

Specific examples of the compound having a group represented by the formula (d) include, for example, the formula (B) described in International Publication WO2015/072554 and paragraph [0058] of Japanese Unexamined Patent Publication No. 2016-118753. Examples thereof include compounds having two or more groups represented by d), compounds described in JP-A-2016-200798, and the like. Among these, compounds represented by any of the following formulas (hd-1) to (hd-8) are preferable.

Examples of the (m+n)-valent organic group having an aromatic ring in A of the formula (e) include (m+n)-valent aromatic hydrocarbon groups having 5 to 30 carbon atoms and aromatic hydrocarbon groups having 5 to 30 carbon atoms. Examples thereof include a (m+n)-valent organic group in which is bonded directly or via a linking group, and a (m+n)-valent group having an aromatic heterocycle. Examples of the aromatic hydrocarbon group include benzene and naphthalene. Examples of the aromatic heterocycle include pyrrole ring, imidazole ring, pyrazole ring, pyridine ring, pyrimidine ring, quinoline ring, isoquinoline ring, carbazole ring, pyridazine ring, pyrazine ring, benzimidazole ring, benzimidazole ring, indole ring, quinoxaline. Ring, 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. In addition, any hydrogen atom of the alkylene group may be substituted with a fluorine atom or an organic group such as a trifluoromethyl group. Specific examples include the compounds described in International Publication WO2010/074269. Preferred specific examples include any of the following formulas (e-1) to (e-9).

Examples of the crosslinkable compound are not limited to these. For example, components other than those disclosed in [0105] to [0116] of WO 2015/060357 may be mentioned. Further, the crosslinkable compounds may be used in combination of two or more kinds.
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 the desired effect is exhibited. However, the amount is more preferably 1 to 15 parts by mass from the viewpoint of less generation of AC afterimage.

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-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl -1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diaza Nonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, 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-glycidoxypropyltriethoxysilane, p -Styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxy Silane cups such as silane, tris-(trimethoxysilylpropyl) isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane Ring agents can be mentioned. When these silane coupling agents are used, the amount used is 0.1 to 30 parts by mass based on 100 parts by mass of the polymer component contained in the liquid crystal aligning agent, from the viewpoint of less generation of AC afterimage. The amount is preferably 0.1 to 20 parts by mass.

<Method for producing liquid crystal alignment film>
The method for producing a liquid crystal alignment film using the liquid crystal alignment agent of the present invention comprises a step of applying the above liquid crystal alignment agent (step (A)), heating the coating film of the liquid crystal alignment agent obtained in the step (A). To obtain a film (step (B)), a step of irradiating the film obtained in step (B) with polarized ultraviolet light (step (C)), and more preferably a film obtained in step (C) Is baked at a temperature of 100° C. or higher and a temperature higher than that of the step (B) (the step (D) is included.

<Process (A)>
The substrate to which the liquid crystal aligning agent used in the present invention is applied is not particularly limited as long as it is a highly transparent substrate, and a plastic substrate such as an acrylic substrate or a polycarbonate substrate can be used together with a glass substrate or a silicon nitride substrate. .. At that time, it is preferable to use a substrate on which an ITO electrode or the like for driving the liquid crystal is formed, from the viewpoint of simplifying the process. Further, in the reflection type liquid crystal display element, an opaque material such as a silicon wafer can be used if only one substrate is used, and in this case, a material that reflects light such as aluminum can be used for the electrode.
The method for applying the liquid crystal aligning agent is not particularly limited, but industrially, a method such as screen printing, offset printing, flexo printing, or inkjet method is generally used. Other coating methods include a dip method, a roll coater method, a slit coater method, a spinner method or a spray method, and these may be used depending on the purpose.

<Process (B)>
The step (B) is a step of baking the liquid crystal aligning agent applied on the substrate to form a film. After applying the liquid crystal aligning agent on the substrate, the solvent is evaporated or the amic acid or amic acid ester in the polymer is heated by a heating means such as a hot plate, a heat circulation type oven or an IR (infrared) type oven. It can be imidized. The drying and firing steps after applying the liquid crystal aligning agent of the present invention can be performed at any temperature and time and may be performed a plurality of times. The temperature for removing the organic solvent of the liquid crystal aligning agent can be, for example, in the temperature range of 40 to 150°C. From the viewpoint of shortening the process, it may be carried out at 40 to 120°C. The firing time is not particularly limited, but examples thereof include 1 to 10 minutes or 1 to 5 minutes. When the thermal imidization of the amic acid or amic acid ester in the polymer is performed, a step of baking at a temperature range of 190 to 250° C. or 200 to 240° C. can be performed after the step of removing the organic solvent. .. The firing time is not particularly limited, but may be 5 to 40 minutes, or 5 to 30 minutes.

<Process (C)>
Step (C) is a step of irradiating the film obtained in step (B) with polarized ultraviolet light. As the ultraviolet rays, ultraviolet rays having a wavelength of 200 to 400 nm are preferably used, and among them, ultraviolet rays having a wavelength of 200 to 300 nm are more preferable. In order to improve the liquid crystal alignment, the substrate coated with the liquid crystal alignment film may be irradiated with ultraviolet rays while being heated at 50 to 250°C. The irradiation dose of the radiation is preferably 1 to 10,000 mJ/cm ² . Among them, 100 to 5,000 mJ/cm ² is preferable. The liquid crystal alignment film thus produced can stably align liquid crystal molecules in a certain direction.
The higher the extinction ratio of polarized ultraviolet rays, the higher anisotropy can be imparted, which is preferable. Specifically, the extinction ratio of linearly polarized ultraviolet light is preferably 10:1 or more, more preferably 20:1 or more.

<Process (D)>
Step (D) is a step of firing the film obtained in step (C) at a temperature of 100° C. or higher and a temperature higher than that of 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 the step (B), but is preferably 150 to 300° C., more preferably 150 to 250° C., further preferably 200 to 250° C. .. The firing time is preferably 5 to 120 minutes, more preferably 5 to 60 minutes, and further preferably 5 to 30 minutes.
If the thickness of the liquid crystal alignment film after firing is too thin, the reliability of the liquid crystal display element may decrease, so that the thickness is preferably 5 to 300 nm, more preferably 10 to 200 nm.

Furthermore, after performing either of the steps (C) or (D), the obtained liquid crystal alignment film may be subjected to contact treatment with water or a solvent.
The solvent used in the above contact treatment is not particularly limited as long as it is a solvent that dissolves the decomposition product generated from the liquid crystal alignment film by irradiation with ultraviolet rays. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, 3- Examples thereof include methyl methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate or cyclohexyl acetate. Among them, water, 2-propanol, 1-methoxy-2-propanol or ethyl lactate is preferable from the viewpoint of versatility and solvent safety. More preferred is water, 1-methoxy-2-propanol or ethyl lactate. You may use a solvent in combination of 2 or more types.

As the above-mentioned contact treatment, that is, treatment of the liquid crystal alignment film irradiated with polarized ultraviolet rays with water or a solvent, immersion treatment or spray treatment (also referred to as spray treatment) can be mentioned. The treatment time in these treatments is preferably 10 seconds to 1 hour from the viewpoint of efficiently dissolving the decomposition product generated from the liquid crystal alignment film by ultraviolet rays. Above all, it is preferable to perform the immersion treatment for 1 to 30 minutes. The solvent used in the contact treatment may be at room temperature or may be heated, but is preferably 10 to 80°C. Above all, 20 to 50° C. is preferable. In addition, from the viewpoint of solubility of the decomposed product, ultrasonic treatment may be performed as necessary.

After the contact treatment, it is preferable to perform rinsing (also referred to as rinsing) with a low boiling point solvent such as water, methanol, ethanol, 2-propanol, acetone or methyl ethyl ketone and baking of the liquid crystal alignment film. At that time, either one of rinsing and baking may be performed, or both may be performed. The firing temperature is preferably 150 to 300°C. Of these, 180 to 250° C. is preferable. More preferably, it is 200 to 230°C. The firing time is preferably 10 seconds to 30 minutes. Of these, 1 to 10 minutes is preferable.

INDUSTRIAL APPLICABILITY The liquid crystal alignment film of the present invention is suitable as a liquid crystal alignment film of a horizontal electric field type liquid crystal display device such as an IPS system or an FFS system, and is particularly useful as a liquid crystal alignment film of an FFS system liquid crystal display device. The liquid crystal display device is obtained by obtaining a substrate with a liquid crystal alignment film obtained from the liquid crystal aligning agent of the present invention, producing a liquid crystal cell by a known method, and using the liquid crystal cell.
As an example of a method of manufacturing a liquid crystal cell, a liquid crystal display element having a passive matrix structure will be described as an example. A liquid crystal display element having an active matrix structure in which a switching element such as a TFT (Thin Film Transistor) is provided in each pixel portion that constitutes image display may be used.

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, for example, ITO electrodes and are patterned so that a desired image can be displayed. Next, an insulating film is provided on each substrate so as to cover the common electrodes and the segment electrodes. The insulating film can be, for example, a SiO ₂ —TiO ₂ film formed by a sol-gel method.
Next, a liquid crystal alignment film is formed on each substrate, one substrate is overlaid with the other substrate so that their liquid crystal alignment film surfaces face each other, and the periphery is bonded with a sealant. It is preferable that a spacer is usually mixed in the sealant in order to control the substrate gap, and spacers for controlling the substrate gap are also scattered on the in-plane portion where the sealant is not provided. An opening that can be filled with liquid crystal from the outside is provided in part of the sealant. Next, a liquid crystal material is injected into the space surrounded by the two substrates and the sealing agent through the opening provided in the sealing agent, and then the opening is sealed with an adhesive. For the injection, a vacuum injection method may be used, or a method utilizing a capillary phenomenon in the atmosphere may be used. As the liquid crystal material, either a positive type liquid crystal material or a negative type liquid crystal material may be used. Next, a polarizing plate is installed. Specifically, a pair of polarizing plates are attached to the surfaces of the two substrates opposite to the liquid crystal layer.

By using the manufacturing method of the present invention as described above, it is possible to suppress the afterimage caused by long-term AC driving that occurs in the liquid crystal display element of the IPS driving method or the FFS driving method. Further, in the step (B), the organic solvent is removed in the temperature range of 40 to 150° C., and then the step (C) is carried out, so that the liquid crystal alignment film can be obtained in a smaller number of steps than in the past. The liquid crystal aligning agent of the present invention is particularly preferably used in the method for producing a liquid crystal aligning film, which includes the step of carrying out step (C) after removing the organic solvent in the temperature range of 40 to 150° C. in step (B). You can

By using the liquid crystal aligning agent of the present invention as described above, it is possible to obtain a liquid crystal aligning film having a high seal adhesiveness with less generation of afterimages due to residual DC and AC afterimages. Further, it is possible to obtain a liquid crystal display element having excellent contrast in which variation in brightness in a plane during black display is suppressed, and a liquid crystal display element having good display quality can be obtained.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. The abbreviations of the compounds and the methods for measuring each property below are as follows.
(solvent)
NMP: N-methyl-2-pyrrolidone, GBL: γ-butyrolactone,
BCS: butyl cellosolve,
(Diamine)
DA-1 to DA-8: compounds represented by the following formulas (DA-1) to (DA-8),
(Tetracarboxylic acid dianhydride)
CA-1 to CA-4: compounds (additives) represented by the following formulas (CA-1) to (CA-4)
C-1: compound represented by the following formula (C-1) C-2: 2,2′-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane S-1: the following formula (S-1 ) A compound represented by

<Viscosity>
Using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.), the sample amount was 1.1 mL, the cone rotor TE-1 (1°34', R24), and the temperature was 25°C.

<Measurement of imidization ratio>
20 mg of polyimide powder was put into an NMR sample tube (NMR sampling tube standard, φ5 (Kusano Scientific Co., Ltd.)), and deuterated dimethyl sulfoxide (DMSO-d6, 0.05% TMS (tetramethylsilane) mixed product) (0. (53 ml) was added and ultrasonic waves were applied to completely dissolve. This solution was measured for proton NMR at 500 MHz with an NMR measuring device (JNW-ECA500, manufactured by JEOL Datum). The imidization ratio is determined by using a proton derived from a structure that does not change before and after imidization as a reference proton. It was calculated by the following formula using the integrated value.
Imidization rate (%)=(1-α·x/y)×100
In the above formula, x is the proton peak integrated value derived from the NH group of amic acid, y is the peak integrated value of the reference proton, and α is one NH group proton of the amic acid in the case of polyamic acid (imidization ratio is 0%). Is the ratio of the number of reference protons to.

[Example of polymer synthesis]
Hereinafter, synthesis examples of polyamic acid and polyimide will be shown. In these nomenclatures, A represents component (A), B represents component (B), and PI represents polyimide.

<Synthesis example 1>
In a 300 mL four-necked flask equipped with a stirrer and a nitrogen inlet tube, 4.89 g (20.0 mmol) of DA-1 and 2.59 g (24.0 mmol) of DA-2 and 4.61 g of DA-3 ( 20.0 mmol) and DA-5 (5.46 g (16.0 mmol)) were weighed out, 197 g of NMP was added, and the mixture was dissolved by stirring while feeding nitrogen. While stirring this 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) was obtained.

<Synthesis example 2>
52.6 g (0.264 mol) of DA-7 and 13.1 g (0.066 mol) of DA-8 were weighed out and added to a 1 L separable flask equipped with a stirrer and a nitrogen introducing tube, and 481.7 g of NMP was added. Then, it was dissolved by stirring while sending nitrogen. While stirring this diamine solution, 41.3 g (0.165 mol) of CA-2 and 124.5 g of NMP were added and reacted at 50° C. for 4 hours. Then, 45.1 g (0.153 mol) of CA-4 and 255.8 g of NMP were added, and the mixture was stirred at 70° C. for 24 hours to obtain a 15 wt% polyamic acid solution (B-1) (viscosity: 895 mPa·s). Obtained.

<Synthesis example 3>
In a 100 mL four-necked flask equipped with a stirrer and equipped with a nitrogen inlet tube, 3.42 g (0.014 mol) of DA-1 was weighed, 30.8 g of NMP was added, and the mixture was stirred while sending nitrogen to dissolve it. While stirring this 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, and a 12 wt% polyamic acid solution (B-2) (viscosity) was added. 129 mPa·s) was obtained.

<Synthesis example 4>
16.4 g (0.035 mol) of DA-6 and 22.2 g (0.091 mol) of DA-1 were weighed and put into a 500 mL separable flask equipped with a stirrer and a nitrogen introducing tube, and 283.6 g of NMP was added. Then, it was dissolved by stirring while sending nitrogen. While stirring this diamine solution, 6.51 g (0.026 mol) of CA-2 and 47.7 g of NMP were added and reacted at 50° C. for 2 hours. After that, 28.8 g (0.098 mol) of CA-4 and 87.9 g of NMP were added, followed by stirring for 12 hours to obtain a 15 wt% polyamic acid solution (B-3) (viscosity: 791 mPa·s). ..

<Synthesis example 5>
100 g of the obtained polyamic acid solution (A-1) was weighed in a 300 mL four-necked flask equipped with a stirrer and equipped with a nitrogen introducing tube, 50 g of NMP was added, and the mixture was stirred for 30 minutes. 16.78 g of acetic anhydride and 5.20 g of pyridine were added to the obtained polyamic acid solution, and the mixture was heated at 50° C. for 3 hours for chemical imidization. The obtained reaction solution is poured into 600 ml of methanol while stirring, the deposited precipitate is collected by filtration, and the same operation is performed twice to wash the resin powder, and then dried at 60° C. for 12 hours. Then, a polyimide resin powder was obtained. The imidation ratio of this polyimide resin powder was 71%. 3.60 g of the obtained polyimide resin powder was placed in a 100 ml Erlenmeyer flask, 26.4 g of NMP was added so that the solid content concentration was 12%, and the mixture was stirred and stirred at 70° C. for 24 hours to dissolve the polyimide solution (A-1- PI) was obtained.

Table 1 below shows the main points of the polyamic acid solution and the polyimide solution obtained in Synthesis Examples 1 to 5.

The values in parentheses in Table 1 represent, for the tetracarboxylic acid component, the compounding ratio (mol part) of each compound to 100 mol parts of the total amount of the tetracarboxylic acid derivative used in the synthesis, and for the diamine acid component, The compounding ratio (mol part) of each compound to 100 mol parts of the total amount of diamines used in the synthesis is shown. Regarding the organic solvent, the compounding ratio (parts by mass) of each organic solvent to the total amount of 100 parts by mass of the organic solvent used in the synthesis is shown.

[Preparation of liquid crystal aligning agent]
<Comparative Example 1>
In 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 0.63 g of NMP and 3. 60 g, 3.0 g of BCS, 0.90 g of GBL solution containing 1% by weight of S-1 and 0.27 g of NMP solution containing 10% by weight of C-1 were added, and the mixture was stirred for 30 minutes with a magnetic stirrer for liquid crystal alignment. The agent (R1) was obtained.

<Example 1>
3.67 g of the polyimide solution (A-1-PI) and 5.50 g of the polyamic acid solution (B-2) were weighed and put in a 20 ml sample tube containing a stirrer, and 0.50 g of NMP and 4. 90 g, 4.00 g of BCS, 1.10 g of GBL solution containing 1% by weight of S-1 and 0.33 g of NMP solution containing 10% by weight of C-1 were added, and the mixture was stirred with a magnetic stirrer for 30 minutes for liquid crystal alignment. The agent (1) was obtained.

<Example 2>
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 0.63 g of NMP and 3. 60 g, 3.0 g of BCS, 0.90 g of GBL solution containing 1% by weight of S-1 and 0.27 g of NMP solution containing 10% by weight of C-1 were added, and the mixture was stirred for 30 minutes with a magnetic stirrer for liquid crystal alignment. The agent (2) was obtained.

<Example 3>
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 0.63 g of NMP and 3. 60 g, 3.0 g of BCS, 0.90 g of GBL solution containing 1% by weight of S-1, 0.027 g of C-2, and 0.27 g of NMP solution containing 10% by weight of C-1 are magnetically added. The mixture was stirred with a stirrer for 30 minutes to obtain a liquid crystal aligning agent (3).

<Example 4>
A 20 ml sample tube containing a stirrer weighs 3.00 g of the polyimide solution (A-1-PI) and 3.60 g of the polyamic acid solution (B-3), 0.45 g of NMP, and 3. 60 g, 3.0 g of BCS, 0.90 g of GBL solution containing 1% by weight of S-1, 0.027 g of C-2, and 0.45 g of NMP solution containing 10% by weight of C-1 are magnetically added. The liquid crystal aligning agent (4) was obtained by stirring with a stirrer for 30 minutes.

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

The numerical value in the parentheses in Table 2 is the blending ratio (parts by mass) of each polymer component or additive with respect to 100 parts by mass in total of the polymer components used in the preparation of the liquid crystal aligning agent for the polymer and the additive. Represent Regarding the organic solvent, the compounding ratio (parts by mass) of each organic solvent to 100 parts by mass of the total amount of the organic solvent used for preparing the liquid crystal aligning agent is shown.

<Production of liquid crystal display element>
A substrate with electrodes was prepared. The substrate is a glass substrate having a size of 30 mm×35 mm and a thickness of 0.7 mm. On the substrate, an IZO electrode having a solid pattern, which constitutes a counter electrode as a first layer, is formed. A SiN (silicon nitride) film formed by the CVD method is formed as a second layer on the counter electrode of the first layer. The film thickness of the second-layer SiN film is 500 nm and functions as an interlayer insulating film. A comb-teeth-shaped pixel electrode formed by patterning the IZO film is arranged as the third layer on the second-layer SiN film to form two pixels of the first pixel and the second pixel. ing. The size of each pixel is 10 mm in length and about 5 mm in width. At this time, the first-layer counter electrode and the third-layer pixel electrode are electrically insulated by the action of the second-layer SiN film.

The pixel electrode of the third layer has a comb-tooth shape formed by arranging a plurality of “doglegged” electrode elements whose central portion is bent at an internal angle of 160°. The width of each electrode element in the lateral direction is 3 μm, and the distance between the electrode elements is 6 μm. The pixel electrode that forms each pixel is configured by arranging a plurality of curved "dogleg"-shaped electrode elements in the central portion, so the shape of each pixel is not rectangular, but is similar to that of the electrode element. It has a shape that resembles a bold "dogleg" bent at a part. Each pixel is divided into upper and lower parts with a central bent portion as a boundary, and has a first region on the upper side and a second region on the lower side of the bent portion.
In addition to the above glass substrate with electrodes (hereinafter, also referred to as the first glass substrate), an ITO film for preventing electrification is formed on the back surface having a columnar spacer with a height of 3.5 μm on the front surface. Then, a second glass substrate was prepared and a set of liquid crystal cells was prepared.

A liquid crystal aligning agent filtered with a filter having a pore size of 1.0 μm was applied to the surface of each of the above-mentioned glass substrates by spin coating, and dried on a hot plate at 80° C. for 2 minutes. After that, a predetermined amount of linearly polarized ultraviolet light having a wavelength of 254 nm with an extinction ratio of 26:1 is applied to the coating film surface through a polarizing plate, and then baked in a hot air circulation oven at 230° C. for 30 minutes to form a liquid crystal having a film thickness of 100 nm. A substrate with an alignment film was obtained. The liquid crystal alignment film formed on the first glass substrate is subjected to an alignment treatment so that the direction that evenly divides the interior angle of the bent portion of the pixel and the alignment direction of the liquid crystal are orthogonal to each other, and the liquid crystal alignment film formed on the second glass substrate. The film was subjected to an alignment treatment so that the alignment direction of the liquid crystal on the first substrate and the alignment direction of the liquid crystal on the second substrate were the same when the liquid crystal cell was manufactured.
Next, a sealant was printed on one of the pair of glass substrates with a liquid crystal alignment film, the other substrate was attached so that the liquid crystal alignment film surfaces faced each other, and the sealant was cured to prepare an empty cell. Liquid crystal MLC-3019 (manufactured by Merck Ltd.) was injected into this 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, left overnight, and then used for evaluation.

[Evaluation]
<In-plane uniformity of contrast>
The twist angle of the liquid crystal display element was evaluated using OPTIPRO-micro manufactured by Shintech. The manufactured liquid crystal display device was placed on a measurement stage, and the standard deviation was calculated by measuring 20 points in the first pixel plane with no voltage applied. The evaluation was "bad" when the twist angle standard deviation was 0.4 or more, and "good" when the twist angle standard deviation was less than 0.4.

<Evaluation of stability of liquid crystal alignment>
Using the liquid crystal display element used in the above evaluation, an AC voltage of 10 VPP was applied at a frequency of 30 Hz for 168 hours under 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.
After leaving, the liquid crystal display element is installed between two polarizing plates arranged so that their polarization axes are orthogonal to each other, and the backlight is turned on with no voltage applied so that the brightness of transmitted light is minimized. The arrangement angle of the liquid crystal display element was adjusted. Then, the rotation angle when the liquid crystal display element was rotated from the angle where the second region of the first pixel was darkest to the angle where the first region was darkest was calculated as an angle Δ. Similarly, for the second pixel, the second region and the first region were compared, and the same angle Δ was calculated. Then, the average value of the angle Δ values of the first pixel and the second pixel was calculated as the angle Δ of the liquid crystal display element. When the value of the angle Δ of this liquid crystal display element exceeds 0.1 degree, it was evaluated as “poor”. When the value of the angle Δ of this liquid crystal cell did not exceed 0.1 degree, it was evaluated as “good”.

<Evaluation of relaxation characteristics of accumulated charge>
Afterimages were evaluated using the following optical systems and the like. The produced liquid crystal display element is placed between two polarizing plates arranged so that their polarization axes are orthogonal to each other, and the LED backlight is turned on with no voltage applied so that the brightness of transmitted light is minimized. The arrangement angle of the liquid crystal display element was adjusted.
Next, a VT curve (voltage-transmittance curve) was measured while applying an AC voltage having a frequency of 30 Hz to this liquid crystal display element, and an AC voltage having a relative transmittance of 23% was calculated as a driving voltage.
In the afterimage evaluation, an AC voltage having a frequency of 30 Hz at which the relative transmittance is 23% was applied to drive the liquid crystal display element, and at the same time, a DC voltage of 1 V was applied for 40 minutes. After that, the applied DC voltage value was set to 0 V, only the application of the DC voltage was stopped, and the device was further driven for 15 minutes in that state.
The evaluation was “good” when the relative transmittance decreased to 27% or less by the time 45 minutes passed after the start of the application of the DC voltage. When it took 45 minutes or more before the relative transmittance decreased to 27% or less, it was evaluated as "poor".
Then, the afterimage evaluation according to the above-described method was performed under the temperature condition in which the temperature of the liquid crystal display element was 23° C.

<Evaluation of seal adhesion>
[Sample preparation]
The liquid crystal aligning agent prepared above was applied onto a 30 mm×40 mm ITO substrate by spin coating. After drying on a hot plate at 80°C for 2 minutes, the coating film surface is irradiated with ultraviolet rays of 254 nm through a polarizing plate, and then baked at 230°C for 20 minutes in a hot air circulation type oven to obtain a coating film having a thickness of 100 nm. A film was formed. Two substrates thus obtained were prepared, a bead spacer having a diameter of 4 μm was applied on the liquid crystal alignment film surface of one substrate, and then a sealant (XN-1500T manufactured by Kyoritsu Chemical Co., Ltd.) was dropped. .. Next, the liquid crystal alignment film surface of the other substrate was placed inside, and bonding was performed so that the overlapping width of the substrates was 1 cm. At that time, the dropping amount of the sealing agent was adjusted so that the diameter of the sealing agent after bonding was 3 mm. After fixing the bonded two substrates with a clip, they were heat-cured at 150° C. for 1 hour to prepare a sample for evaluation of adhesion.

[Measurement of adhesion]
The sample substrate produced above is fixed on the top and bottom substrates using a tabletop precision universal testing machine (AGS-X 500N, manufactured by Shimadzu Corp.), and then pressed from the top of the center of the substrate for peeling. The strength (N) at that time was measured. A value obtained by standardizing the peeling strength (N) by the adhesion area (mm ² ) was defined as the seal adhesion (N/mm ² ) in each sample, and was evaluated as “good” when it was larger than 5 N/mm ² . .. When it was less than 5 N/mm ² , it was evaluated as “poor”.

The evaluation results of the liquid crystal display devices of Examples 1 to 4 and Comparative Example 1 are shown in Table 3 below.

The liquid crystal aligning agent of the present invention is useful for forming a liquid crystal aligning film in a wide variety of liquid crystal display devices such as an IPS driving system and an FFS driving system.
The entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2018-227376 filed on Dec. 4, 2018 are cited herein as disclosure of the specification of the present invention. , Take in.

Claims (19)

1. A liquid crystal aligning agent comprising the following component (A) and component (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 (3).
   

   

   (R ₁ to R ₄ each independently contain 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, or a fluorine atom. Which is a monovalent organic group having 1 to 6 carbon atoms or a phenyl group, and at least one of R ₁ to R ₄ represents a group other than a hydrogen atom in the above definition, and Y ₁ is represented by the following formula (H): It represents a divalent organic group having a partial structure represented.)
   

   

   (Q ³ is a structure represented by —(CH ₂ ) _n — (n is an integer of 2 to 20), and any —CH ₂ — may be replaced with —O—. Oxygen atoms are not directly bonded to each other.) Any hydrogen atom on the two benzene rings may be replaced with a monovalent organic group. * Represents a bond. )
   

   

   (X ₃ represents a tetravalent organic group derived from an aromatic dianhydride. Y ₃ represents a divalent organic group having a partial structure represented by the following formula (m), and * represents a bond. R ₃₀ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and Z ₃₁ and Z ₃₂ each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms which may have a substituent. Group, alkenyl group having 2 to 10 carbon atoms which may have a substituent, alkynyl group having 2 to 10 carbon atoms which may have a substituent, tert-butoxycarbonyl group, or 9-fluorenylmethoxycarbonyl group Represents a group.)
   

   
2. The liquid crystal aligning agent according to claim 1, wherein the component (A) is a polymer further having a repeating unit represented by the following formula (2).
   

   

   (X ₂ represents a tetravalent organic group having a 5- or more-membered alicyclic structure. Y ₂ represents a divalent organic group having a partial structure represented by the formula (H).)
3. _{X 1} in the formula (1), the _{X 2} of formula (2), each independently, is a tetravalent organic group represented by any one of the following formulas (X2-1) ~ (X2-12) The liquid crystal aligning agent according to claim 1 or 2.
   

   
4. Y ₁ and Y _{2 in the} formulas (1) and (2) each independently represent a divalent organic group having a partial structure represented by any one of the following formulas (H-1) to (H-6). The liquid crystal aligning agent according to any one of claims 1 to 3, which is
   

   
5. Y ₁ and Y _{2 in the} formulas (1) and (2) are each independently a divalent organic group represented by any of the following formulas (h-1) to (h-7), The liquid crystal aligning agent according to any one of claims 1 to 4.
   

   
6. The polymer (A) further has at least one type of repeating unit selected from the group consisting of repeating units represented by the following formula (4) and repeating units represented by the following formula (5): 6. The liquid crystal aligning agent according to any one of 1 to 5.
   

   

   (R ₄₁ to R ₄₄ have the same meanings as R ₁ to R _{4 in} the formula (1), respectively, and Y ₄ and Y ₅ represent a divalent organic group represented by the following formula (I). X ₅ represents It has the same meaning as X _{2 in the} above formula (2).)
   

   

   (Q represents a single bond or an oxygen atom, n represents 0 to 2. Any hydrogen atom on the benzene ring may be replaced with a monovalent organic group.)
7. The equation _{Y 5} of _{Y 4} and the formula (4) (5) is a divalent organic group represented by any one of the following formulas (I-1) ~ (I -3), according to claim 6 The liquid crystal aligning agent according to item 1.
   

   

   (* represents a bond.)
8. The polymer (A) further has at least one type of repeating unit selected from the group consisting of repeating units represented by the following formula (6) and repeating units represented by the following formula (7). 8. The liquid crystal aligning agent according to any one of items 7 to 7.
   

   

   (R ₆₁ to R ₆₄ have the same meaning as R ₁ to R _{4 in} the formula (1), and Y ₆ and Y ₇ each independently have a partial structure represented by the following formula (J-1): Represents a divalent organic group or a divalent organic group represented by the following formula (J-2), wherein X ₇ has the same meaning as X _{2 in the} above formula (2).
   

   

   (Q ₅ is a single bond, —(CH ₂ ) _n — (n is an integer of 1 to 20), or —O ₂ ) under the condition that any —CH ₂ — of —(CH ₂ ) _n — is not adjacent to each other. _{-, - COO -, - OCO} -, - NQ 9 -, - NQ 9 CO -, - CONQ 9 -, - NQ 9 CONQ 10 -, - NQ 9 COO -, - a group to be replaced in -OCOO-, Q ₉ and Q ₁₀ each independently represent a hydrogen atom or a monovalent organic group;
   Q ₆ and Q ₇ each independently represent a group having —H, —NHD, —N(D) ₂ , —NHD, or a group having —N(D) ₂ . Q ₈ represents a group having —NHD, —N(D) ₂ , and —NHD, and a group having —N(D) ₂ . D represents a carbamate-based protecting group. However, at least one of Q ₅ , Q ₆ and Q ₇ has a carbamate-based protecting group in the group. *1 represents a bond. ),
9. 9. The partial structure represented by the formula (J-1) is a partial structure represented by any of the following formulas (J-1-a) to (J-1-d). Liquid crystal aligning agent.
   

   
10. 10. The liquid crystal aligning agent according to claim 1, wherein X _{3 of the} formula (3) is selected from the following formulas (X3-1) to (X3-2).
    

    

    (X and y are each independently a single bond, ether, carbonyl, ester, alkanediyl group having 1 to 5 carbon atoms, 1,4-phenylene, sulfonyl or amide group. j and k are each independently. , 0 or 1. * represents a bond.)
11. The liquid crystal aligning agent according to any one of claims 1 to 10, wherein Y _{3 in the} formula (3) is a divalent organic group represented by (Y3-1) or (Y3-2).
    

    
12. The polymer (B) has at least one repeating unit selected from the group consisting of repeating units represented by the following formula (8) and repeating units represented by the following formula (9): 11. The liquid crystal aligning agent according to any one of 11.
    

    

    (X ₈ is a tetravalent organic group having a 5- or more-membered alicyclic structure, and X ₉ is derived from a tetravalent organic group having a 5- or more-membered alicyclic structure or an aromatic dianhydride. Represents a tetravalent organic group, Y ₈ has the same meaning as Y _{3 in the} formula (3), and Y ₉ represents a divalent group having a partial structure represented by the following formula (n-1) or (n-2). Z ₈₁ , Z ₈₂ , Z ₉₁ , and Z ₉₂ have the same meanings as Z ₃₁ and Z ₃₂ of the above formula (3), R ₈ and R ₉ are each independently a hydrogen atom or a carbon atom. An alkyl group of the numbers 1 to 4, Q ₁ and Q ₂ each represent a hydrogen atom or a methyl group.)
    

    
13. The content ratio of the polymer (A) and the polymer (B) is 5/95 to 95/5 by weight ratio of the polymer (A)/polymer (B). The liquid crystal aligning agent according to any one of items.
14. A liquid crystal alignment film obtained from the liquid crystal alignment agent according to any one of claims 1 to 13.
15. A liquid crystal display device comprising the liquid crystal alignment film according to claim 14.
16. A method for producing a liquid crystal alignment film, comprising the following steps (A) to (C).
    Step (A): A step of applying the liquid crystal aligning agent according to any one of claims 1 to 13 onto a substrate.
    Step (B): A step of heating the coating film of the liquid crystal aligning agent obtained in the step (A) to obtain a film.
    Step (C): A step of irradiating the film obtained in step (B) with polarized ultraviolet light.
17. The method for producing a liquid crystal alignment film according to claim 16, further comprising the following step (D).
    Step (D): A step of firing the film obtained in the step (C) at 100° C. or higher and at a temperature higher than that in the step (B).
18. The method for producing a liquid crystal alignment film according to any one of claims 16 to 17, wherein the coating film is heated in the temperature range of 40 to 180°C in the step (B).
19. A liquid crystal display device comprising a liquid crystal alignment film obtained by the method for producing a liquid crystal alignment film according to any one of claims 16 to 18.