JPWO2020175559A1 - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal display element using it - Google Patents

Abstract

Provided is a liquid crystal alignment agent capable of obtaining a liquid crystal alignment film having good orientation and good adhesion to a sealing agent. A liquid crystal alignment agent comprising a polymer (A) having a repeating unit represented by the following formulas (1), (2), (3) and (4). [Chemical formula 1] (R1 to R4 independently represent a hydrogen atom, a halogen atom, an alkyl group, etc., Y1 represents a divalent organic group having a partial structure represented by the formula (H), and Q3. Is a structure represented by − (CH2) n−, X2 is a tetravalent organic group having an alicyclic structure of 5 members or more, and Y2 has a partial structure represented by the formula (H). Representing a divalent organic group, R31 to R34 have the same meaning as R1 to R4, X4 has the same meaning as X2, and Y3 and Y4 represent the divalent organic group represented by the formula (I).

Description

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

Conventionally, liquid crystal devices have been widely used as display units for personal computers, mobile phones, smartphones, television receivers, and the like. The liquid crystal apparatus 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 orientation of liquid crystal molecules in the liquid crystal layer, and pixels. It is equipped with a thin film transistor (TFT) that switches the electric signal supplied to the electrodes. As the driving method of the liquid crystal molecule, a vertical electric field method such as a TN method and a VA method, and a horizontal electric field method such as an IPS method and an FFS (fringe field switching) method are known.

Currently, the most widely used liquid crystal alignment film in the industry is a film made of polyamic acid and / or a polyimide imidized with a polyamic acid formed on an electrode substrate, and the surface of the film is made of a cloth such as cotton, nylon, or polyester. It is manufactured by performing a so-called rubbing process of rubbing in one direction. The rubbing process is a simple and highly productive industrially useful method. However, with the increase in performance, definition, and size of liquid crystal display elements, scratches on the surface of the alignment film generated by the rubbing process, dust generation, the effects of mechanical force and static electricity, and the in-plane alignment process Various problems such as non-uniformity of the above have been clarified. As a liquid crystal alignment treatment method instead of the rubbing treatment, a photoalignment method for imparting a liquid crystal alignment ability by irradiating polarized radiation is known. As the liquid crystal alignment treatment by the photoalignment method, one using a photoisomerization reaction, one using a photocrosslinking reaction, one using a photodecomposition reaction, etc. have been proposed (see Non-Patent Document 1 and Patent Document 1). ..

The liquid crystal alignment film, which is a constituent member of the liquid crystal display element, is a film for uniformly arranging liquid crystals, but not only the alignment uniformity of the liquid crystal but also various characteristics are required. For example, electric charges are accumulated in the liquid crystal alignment film by the voltage that drives the liquid crystal, which affects the display as afterimages and burn-in (hereinafter referred to as afterimages derived from residual DC), and significantly deteriorates the display quality of the liquid crystal display element. Therefore, a liquid crystal alignment agent that overcomes these problems has been proposed (see Patent Document 2).

Further, in the IPS system and the FFS drive system, the stability of the liquid crystal orientation is also important. If the stability of the liquid crystal orientation is small, the liquid crystal does not return to the initial state when the liquid crystal is driven for a long time, which causes 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 alignment agent.

Further, with the spread of tablets and smartphones, the development of a liquid crystal display element having a narrow frame that secures a display area as wide as possible is being promoted. Since it became necessary to apply a sealant on the liquid crystal alignment film due to this narrowing of the frame, Patent Document 4 discloses a liquid crystal alignment agent having good adhesion to the sealant while maintaining the liquid crystal alignment. There is.

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

"Liquid Crystal Light Alignment Film" Kidowaki, Ichimura Functional Materials November 1997 Vol. 17, No. 11 Pages 13-22

In addition, the demand for higher definition for liquid crystal display elements is increasing, and it is more important than ever to show good display quality.
The present invention has been made in view of the above circumstances, and the liquid crystal alignment film has good orientation of the liquid crystal and also has good adhesion to the sealing agent, and the adhesion between the liquid crystal alignment film and the sealing agent is good. It is a major object of the present invention to provide a liquid crystal alignment agent capable of narrowing the frame because of its good condition and obtaining a liquid crystal display element showing good display quality.

（Ｒ_１からＲ_４はそれぞれ独立して、水素原子、ハロゲン原子、炭素数１〜６のアルキル基、炭素数２〜６のアルケニル基、炭素数２〜６のアルキニル基、フッ素原子を含有する炭素数１〜６の１価の有機基、又はフェニル基であり、同一でも異なってよいが、Ｒ_１からＲ_４の少なくとも一つは上記定義中の水素原子以外の基を表す。Ｙ_１は下記式（Ｈ）で表される部分構造を有する２価の有機基を表す。）

（Ｑ^３は−（ＣＨ_２）_ｎ−で表される構造であり（ｎは２〜２０の整数である。）、任意の−ＣＨ_２−は−Ｏ−及び−Ｃ（＝Ｏ）−から選ばれる基に置き換えられてもよいが、酸素原子同士が直接結合することはない。２つのベンゼン環上の任意の水素原子は１価の有機基で置き換えられてもよい。＊は結合手を表す。）

（Ｘ_２は、５員環以上の脂環構造を有する４価の有機基である。Ｙ_２は上記式（Ｈ）で表される部分構造を有する２価の有機基を表す。）

（式（３）におけるＲ_３１からＲ_３４は、それぞれ、上記式（１）のＲ_１からＲ_４と同義である。式（４）におけるＸ_４は上記式（２）のＸ_２と同義である。Ｙ_３、Ｙ_４は下記式（Ｉ）で表される２価の有機基を表す。）

（＊は結合手を表す。）As a result of diligent research, the present inventor has found that the above problems can be solved by using a liquid crystal aligning agent containing a polymer component having a specific repeating unit, and has completed the present invention. rice field.
The gist of the present invention is as follows.
A liquid crystal alignment agent comprising a polymer (A) having a repeating unit represented by the following formula (1), the following formula (2), the following formula (3), and the following formula (4).

(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, and a fluorine atom. It is a monovalent organic group having 1 to 6 carbon atoms or a phenyl group, which may be the same or different, but _{at least one of R 1} to R ₄ represents a group other than the hydrogen atom in the above definition. Y _{1 represents a group other than the hydrogen atom.} Represents a divalent organic group having a partial structure represented by the following formula (H).)

(Q ³ is a structure represented by − (CH ₂ ) _n − (n is an integer of 2 to 20), and any −CH ₂ − is from −O− and −C (= O) −. It may be replaced with a group of choice, but the oxygen atoms do not bond directly to each other. Any hydrogen atom on the two benzene rings may be replaced with a monovalent organic group. * Is the bond. show.)

(X ₂ is a tetravalent organic group having an alicyclic structure of 5 members or more. Y ₂ represents a divalent organic group having a partial structure represented by the above formula (H)).

_{(R 31} to R ₃₄ in the formula (3) are _{synonymous with R 1} to R _{4 in} the above formula (1), respectively _{. X 4} in the formula (4) is synonymous with _{X 2 in the} above formula (2). Y ₃ and Y ₄ represent divalent organic groups represented by the following formula (I).)

(* Indicates a bond.)

According to the liquid crystal alignment agent of the present invention, the liquid crystal alignment film has good orientation of the liquid crystal and has good adhesion to the sealing agent, and the liquid crystal alignment film has good adhesion to the sealing agent. The frame can be narrowed, and a liquid crystal display element showing good display quality can be obtained.

Hereinafter, each component contained in the liquid crystal alignment agent of the present invention and other components optionally blended will be described.
<Polymer (A)>
The liquid crystal alignment agent of the present invention contains a polymer (A) having a repeating unit represented by the above formula (1), the above formula (2), the above formula (3) and the above formula (4). With such a configuration, a liquid crystal alignment film with less generation of AC afterimage can be obtained, and a liquid crystal display element having excellent contrast can be obtained.

In the above equations (1) and (2), X ₂ , Y ₁ , Y ₂ , R ₁ , R ₂ , R ₃ , and R ₄ are as defined above.

Specific examples of the alkyl groups 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 and s-butyl group. Examples thereof include a t-butyl group and an 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, and these may be linear or branched. Specific examples of the alkynyl group having 2 to 6 carbon atoms in R _{1 to} R ₄ include an ethynyl group, a 1-propynyl group, a 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, an iodine atom and the like. Examples of the monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom include a fluoromethyl group and a trifluoromethyl group. From photoreactive high aspect, R ₁ to R ₄ is a hydrogen atom or a methyl group, preferably from R ₁ at least one R ₄ is a methyl group, and more preferably at least of R ₁ through R ₄ It is preferable that two are methyl groups. More preferably, R ₁ and R ₄ are methyl groups and R ₂ and R ₃ are hydrogen atoms.

Specific examples of the monovalent organic group substituting an arbitrary hydrogen atom on the benzene ring in the above formula (H) include a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, and carbon. number 2-6 alkynyl group, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom. the structure illustrated are mentioned in the above R ₁ to R _4.
Examples of the partial structure represented by the above formula (H) include partial structures represented by any of the following formulas (H-1) to (H-7) from the viewpoint of less generation of AC afterimages.

_{As a preferable 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-8) is used from the viewpoint of less generation of AC afterimage. Can be mentioned.

The polymer (A) has a repeating unit represented by the above formula (2) from the viewpoint of increasing heat resistance.
The tetravalent organic group X ₂ in formula (2) is preferably a tetravalent organic group having an alicyclic structure 5-8 membered ring, 4 having an alicyclic structure 5-7 membered ring It is more preferably a valent organic group. The alicyclic structure having five or more members is the number of atoms constituting the ring in each ring contained in the polycyclic structure when the alicyclic structure to which the imide group is bonded is a polycyclic structure. Indicates that all of them are 5 or more. Further, the alicyclic structure may be bonded to at least one of two imide groups, and may have a chain hydrocarbon structure or an aromatic ring structure together with the alicyclic structure.

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

_{Among them, X 2} of the formula (2) is more preferably any one of (X2-1) to (X2-4) from the viewpoint of generating less AC afterimage and increasing the contrast of the liquid crystal display element.
_{The preferred specific example of Y 2} in the above formula (2) is the same as the preferred specific example _{of Y 1} in the above formula (1).

For the polymer (A), from the viewpoint of having less AC afterimage, the total of the repeating unit represented by the above formula (1) and the repeating unit represented by the above formula (2) is preferably added to all the repeating units. It contains 1 to 95 mol%, more preferably 5 to 90 mol%.
Further, the ratio ((1): (2)) of the polymer (A) to the repeating unit represented by the above formula (1) and the repeating unit represented by the above formula (2) is from 70:30. It is preferably 99: 1, more preferably 75:25 to 98: 2, and even more preferably 80:20 to 97: 3.

The polymer (A) has a repeating unit represented by the above formula (3) and a repeating unit represented by the above formula (4) from the viewpoint of enhancing the contrast and the seal adhesion of the liquid crystal display element.
For the polymer (A), the total of the repeating unit represented by the above formula (3) and the repeating unit represented by the above formula (4) is preferably 5 with respect to all the repeating units from the viewpoint of having less AC afterimage. It is more preferably contained in an amount of ~ 99 mol%, particularly preferably 10 to 95 mol%.
The ratio ((3): (4)) of the polymer (A) to the repeating unit represented by the above formula (3) and the repeating unit represented by the above formula (4) is 70:30 to 99. It is preferably: 1, more preferably 75:25 to 98: 2, and even more preferably 80:20 to 97: 3.

The ratio ((1): (3)) of the polymer (A) to the repeating unit represented by the above formula (1) and the repeating unit represented by the above formula (3) is 1:99 to 99 :. It is preferably 1, more preferably 5:95 to 80:20, and even more preferably 10:90 to 70:30.
The ratio ((2): (4)) of the polymer (A) to the repeating unit represented by the above formula (2) and the repeating unit represented by the above formula (4) is 1: 99 to 99 :. It is preferably 1, more preferably 5:95 to 80:20, and even more preferably 10:90 to 70:30.

In the polymer (A), the total of the repeating units represented by the above formulas (1), (2), (3) and (4) is added to all the repeating units of the polymer (A). It is more preferably contained in an amount of 6 to 100 mol%, particularly preferably 15 to 100 mol%.

（Ｒ_５１からＲ_５４は、それぞれ、上記式（１）のＲ_１からＲ_４と好ましい具体例も含めて同義であり、Ｙ_５、Ｙ_６は、それぞれ独立して、下記式（Ｊ−１）で表される部分構造を有する２価の有機基、又は下記式（Ｊ−２）で表される２価の有機基を表す。式（６）におけるＸ_６は上記式（２）のＸ_２と同義である。）

The polymer (A) is at least one selected from the group consisting of a repeating unit represented by the following formula (5) and a repeating unit represented by the following formula (6) from the viewpoint of further enhancing the adhesion to the sealant. It may have a kind of repeating unit.

(R ₅₁ to R _{54 are synonymous with R 1} to R ₄ of the above formula (1), respectively, including preferable specific examples, and Y ₅ and Y ₆ are independently represented by the following formula (J-1). ) Represents a divalent organic group having a partial structure or a divalent organic group represented by the following formula (J-2). X ₆ in the formula (6) is X in the above formula (2). _It is synonymous with 2.)

The formula (J-1), wherein (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 that are not adjacent each - - any -CH _{2 in, - COO -, - OCO -} , - NQ 9 -, - NQ 9 CO -, - CONQ 9 -, - NQ 9 CONQ 10 -, - It is a group that can be replaced with NQ _{9 COO-, or -OCOO-.} Q ₉ and Q ₁₀ independently represent a hydrogen atom or a monovalent organic group.
Further, Q ₆ and Q ₇ 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, a group having a -NHD, or -N a _{(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. Provided _that at least one of Q 5, _{Q 6} and _{Q 7} have the carbamate protecting group in the radical. * 1 represents a bond.

Preferred specific examples of Y ₅ and Y ₆ are represented by any of the following formulas (J-1-a) to (J-1-d) and (J-2-1) from the viewpoint of having less AC afterimage. Divalent organic groups can be mentioned. Boc represents a tert-butoxycarbonyl group.

The polymer (A) has the following formula (PI-A) in addition to the repeating units represented by the above formulas (1) to (4) and the repeating units represented by the above formulas (5) and (6). It may have at least one repeating unit selected from the group consisting of the repeating unit represented by -1) and the repeating unit represented by (PA-1).

（Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４は、上記式（１）のＲ_１、Ｒ_２、Ｒ_３、Ｒ_４と同義である。）Wherein _(PI-A-1), X I1 represents a tetravalent organic _{group, Y I1} represents a divalent organic group. However, when X _I1 is synonymous with a tetravalent organic group represented by the following formula (g) or X _{2 of the above formula (2), Y I 1} has a partial structure represented by the above formula (H). A divalent organic group having, a divalent organic group represented by the above formula (I), a divalent organic group having a partial structure represented by the above formula (J-1), the above formula (J-2). Represents a structure other than the divalent organic group represented by. Examples of X _I1, tetravalent organic group represented by the following formula (g), other tetravalent organic groups exemplified by _{X 2} in the formula (2), the following formula _(X I1 -1) ~ (X I1 _-13) tetravalent organic group represented by any one of such tetravalent organic radical derived from an aromatic tetracarboxylic acid 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).)

（ｘ及びｙは、それぞれ独立に、単結合、エーテル（−Ｏ−）、カルボニル（−ＣＯ−）、エステル（−ＣＯＯ−）、炭素数１〜５のアルカンジイル基、１，４−フェニレン、スルホニル、又はアミド基である。ｊ及びｋは、０又は１である。＊は結合手を表す。）

The _{aromatic tetracarboxylic acid dianhydride that gives the tetravalent organic group of X 11} 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. be. Specific examples include a tetravalent organic group represented by any of the following formulas (X3-1) to (X3-2), and a table according to any of the following formulas (Xr-1) to (Xr-7). The tetravalent organic group to be used can be mentioned.

(X and y are independently single bond, ether (-O-), carbonyl (-CO-), ester (-COO-), alkanediyl group having 1 to 5 carbon atoms, 1,4-phenylene, respectively. It is a sulfonyl or amide group. J and k are 0 or 1. * Represents a bond.)

In the formula (PI-A-1), _{as a specific example of the divalent organic group of YI1} , the divalent organic group having a partial structure represented by the above formula (H) is represented by the above formula (I). In addition to the divalent organic group represented by the above formula (J-1), the divalent organic group having a partial structure represented by the above formula (J-1), and the divalent organic group represented by the above formula (J-2), the following formula A divalent organic group represented by any of (o-1) to (o-23), formulas (Y-1) to (Y-1) to (Y-1) to No. 2018/117239 (hereinafter, also referred to as WO). Examples thereof include a group represented by any one of Y-167).

In formula (PA-1), X _A1 represents a tetravalent organic group and Y _A1 represents a divalent organic group. Specific examples of the X _A1 include the structure exemplified by _{the X I1} of the above formula (PI-A-1). Specific examples of Y _A1 include the structure exemplified by _{Y I1} of the above formula (PI-A-1).

In formula (PA-1), _RA1 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Z _A11 and Z _A12 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, and a substituent. It is an alkynyl group having 2 to 10 carbon atoms, a tert-butoxycarbonyl group, or a 9-fluorenylmethoxycarbonyl group which may have a group.

Specific examples of the alkyl group of 1 to 5 carbon atoms in the _{R A1,} a methyl group, an ethyl group, a propyl group, i- propyl, n- butyl group, i- butyl, s- butyl, t- butyl Groups, n-pentyl groups and the like can be mentioned. 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 the _{Z A11, Z A12,} in addition to the specific examples of the exemplified alkyl group having 1 to 5 carbon atoms in the above _{R 1,} a hexyl group, a heptyl group, an octyl group , Nonyl group, decyl group and the like. Specific examples of the alkenyl groups of the Z _A11, Z 2 to 10 carbon atoms _A12, vinyl group, propenyl group, butynyl group and the like can be mentioned, which may be be linear or branched. Examples of the alkynyl group of the _{Z A11, Z} 2 to 10 carbon atoms _A12, ethynyl, 1-propynyl, 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), a hydroxyl group, a cyano group, an alkoxy group and the like. ..

The ratio ((5): (6)) of the polymer A when the repeating unit represented by the above formula (5) and the repeating unit represented by the above formula (6) are contained is 70:30 to 99. It is preferably: 1, more preferably 75:25 to 98: 2, and even more preferably 80:20 to 97: 3.

In the polymer (A), the total of the repeating unit represented by the above formula (5) and the repeating unit represented by the above formula (6) is 1 to 1 with respect to all the repeating units of the polymer (A). It is preferably 40 mol%, more preferably 1 to 30 mol%, still more preferably 5 to 30 mol%.
In this case, the total of the repeating units represented by the above formulas (1), (2), (3) and (4) is 6 to 99 mol with respect to all the repeating units of the polymer (A). %, More preferably 15-99 mol%, more preferably 15-95 mol%.

<Second polymer>
The liquid crystal alignment agent of the present invention is a composition containing the above-mentioned polymer (A) and an organic solvent, and may contain two or more kinds of polymers (A) having different structures. Further, the liquid crystal alignment agent of the present invention may contain a polymer other than the polymer (A) (hereinafter, also referred to as a second polymer) and various additives.
When the liquid crystal alignment agent of the present invention contains the second polymer, the content ratio of the polymer (A) to the total polymer components is preferably 5% by mass or more, preferably 5 to 95% by mass, more. Preferably, it is 10 to 90% by mass.

The second polymer includes polyamic acid, polyimide, polyamic acid ester, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene or its derivative, poly (styrene-phenylmaleimide) derivative, and poly (meth). Examples include acrylate.

In particular, a polyamic acid (hereinafter, also referred to as a second polyamic acid) obtained from the tetracarboxylic dianhydride component and the diamine component is preferable as the second polymer.

（Ａは４価の有機基であり、好ましくは炭素数４〜３０の４価の有機基である。）Examples of the tetracarboxylic dianhydride component for obtaining the second polyamic acid include a compound represented by the following formula (11). The tetracarboxylic dianhydride component may be composed of two or more kinds of compounds.

(A is a tetravalent organic group, preferably a tetravalent organic group having 4 to 30 carbon atoms.)

The following is an example of preferable A, but the present invention is not limited thereto.

Of the above, (A-1) and (A-2) are preferable from the viewpoint of further improving the photo-orientation, and (A-4) is preferable from the viewpoint of further improving the relaxation rate of the accumulated charge, and (A) is preferable. −15) to (A-17) and the like are preferable from the viewpoint of further improving the liquid crystal orientation and the relaxation rate of the accumulated charge.

（Ｙ_９は２価の有機基を表す。２つのＡ_９は、それぞれ独立して、水素原子又は、炭素数１〜５のアルキル基、炭素数２〜５のアルケニル基、又は炭素数２〜５のアルキニル基である。液晶配向性の観点から、Ａ_９は水素原子又はメチル基が好ましい。）The diamine component for obtaining the second polyamic acid can be appropriately determined depending on the intended purpose, and for example, a diamine represented by the following formula (12) can be used.

_{(Y 9} .2 one _{A 9} representing a divalent organic group, each independently, a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or 2 carbon atoms 5 is a alkynyl group. from the viewpoint of liquid crystal alignment property, a ₉ is hydrogen atom or a methyl group.)

For the purpose of improving electrical properties and relaxation properties, Y ₉ is a divalent organic group having a secondary or tertiary nitrogen atom, or a divalent organic group having -NH-CO-NH- in the molecule. preferable.
Specific examples of the diamine represented by the formula (12) in the case where Y ₉ is a divalent organic group having a secondary or tertiary nitrogen atom are any of the following (a) to (d). Diamine can be mentioned.

（Ｒ^１は水素原子、フッ素原子、シアノ基、ヒドロキシ基、又はメチル基を表す。２つのＲ^２は、それぞれ独立して、単結合又は基「＊１−Ｒ^３−Ｐｈ−＊２」を表し、Ｒ^３は、単結合、−Ｏ−、−ＣＯＯ−、−ＯＣＯ−、−（ＣＨ_２）_ｌ−、−Ｏ（ＣＨ_２）_ｍＯ−、−ＣＯＮＨ−、及び−ＮＨＣＯ−から選ばれる２価の有機基を表す。ｌ、ｍは１〜５の整数を表す。＊１は式（ｐｒ）中のベンゼン環と結合する部位を表し、＊２は式（ｐｒ）中のアミノ基と結合する部位を表す。Ｐｈはフェニレン基を表す。ｎは１〜３である。）(A) A diamine having a pyrrole structure according to WO2017 / 126627, preferably a diamine having a structure represented by the following formula (pr).

^{(R 1} is a hydrogen atom, a fluorine atom, a cyano group, hydroxy group, or .2 one ^{R 2} represents methyl group are each independently, a single bond or a group ^"* 1-R 3 -Ph- ^* 2" Represented, R ³ is selected from single bond, -O- _{, -COO-, -OCO-,-(CH 2} ) _l- , -O (CH ₂ ) _m O-, -CONH-, and -NHCO-. Represents a divalent organic group. L and m represent an integer of 1 to 5. * 1 represents a site bonded to a benzene ring in the formula (pr), and * 2 represents an amino group in the formula (pr). Represents the site of binding. Ph represents a phenylene group; n is 1-3.)

(B) A diamine having a pyrrole structure according to WO2018 / 062197, preferably a diamine having a structure represented by the following formula (pn).

（Ｒ^１及びＲ^２は、それぞれ独立に、水素原子又はメチル基を表す。Ｒ^３は単結合又は基「＊１−Ｒ^４−Ｐｈ−＊２」を表し、Ｒ^４は単結合、−Ｏ−、−ＣＯＯ−、−ＯＣＯ−、−（ＣＨ_２）_ｌ−、−Ｏ（ＣＨ_２）_ｍＯ−、−ＣＯＮＨ−、及び−ＮＨＣＯ−から選ばれる２価の有機基を表し（ｌ、ｍは１〜５の整数を表す）、＊１は式（ｐｎ）中のベンゼン環と結合する部位を表し、＊２は式（ｐｎ）中のアミノ基と結合する部位を表す。Ｐｈはフェニレン基を表す。ｎは１〜３を表す。）

(R ¹ and R ² independently represent a hydrogen atom or a methyl group. R ³ represents a single bond or a group "* 1-R ^4- Ph- * 2", and R ⁴ 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 that binds to a benzene ring in the formula (pn), * 2 represents a site that binds to an amino group in the formula (pn), and Ph represents a phenylene group. Represents. N represents 1 to 3.)

（Ｒ^１は水素原子又はメチル基を表し、Ｒ^２はメチル基を表す。）(C) A diamine having a carbazole structure according to WO2018 / 110354, preferably a diamine having a structure represented by the following formula (cz).

(R ¹ represents a hydrogen atom or a methyl group, and R ² represents a methyl group.)

（Ｘはビフェニル環又はフルオレン環である。Ｙはベンゼン環、ビフェニル環、又は−Ｐｈ−Ｚ−Ｐｈ−から選ばれる基であり、Ｐｈはフェニレン基を表す。Ｚは−Ｏ−、−ＮＨ−、−ＣＨ_２−、−ＳＯ_２−、−Ｃ（ＣＨ_３）_２−又は−Ｃ（ＣＦ_３）_２−で表される２価の基である。Ａ及びＢは、水素原子又はメチル基である。）、２，３−ジアミノピリジン、２，６−ジアミノピリジン、３，４−ジアミノピリジン、２，４−ジアミノピリミジン、５，６−ジアミノ−２，３−ジシアノピラジン、５，６−ジアミノ−２，４−ジヒドロキシピリミジン、２，４−ジアミノ−６−ジメチルアミノ−１，３，５−トリアジン、１，４−ビス（３−アミノプロピル）ピペラジン、４，４’−［４，４’−プロパン−１，３−ジイルビス（ピペリジン−１，４−ジイル）］ジアニリン、２，４−ジアミノ−６−イソプロポキシ−１，３，５−トリアジン、２，４−ジアミノ−６−メトキシ−１，３，５−トリアジン、２，４−ジアミノ−６−フェニル−１，３，５−トリアジン、２，４−ジアミノ−６−メチル−１，３，５−トリアジン、２，４−ジアミノ−１，３，５−トリアジン、４，６−ジアミノ−２−ビニル−１，３，５−トリアジン、３，５−ジアミノ−１，２，４−トリアゾール、６，９−ジアミノ−２−エトキシアクリジンラクテート、３，８−ジアミノ−６−フェニルフェナントリジン、１，４−ジアミノピペラジン、３，６−ジアミノアクリジン、ビス（４−アミノフェニル）−Ｎ−フェニルアミン、４，４’−ジフェニル−Ｎ−メチルアミン、４，４’−ジアミノジフェニルアミン、３，６−ジアミノカルバゾール、９−メチル−３，６−ジアミノカルバゾール、９−エチル−３，６−ジアミノカルバゾール、下記式（ｗ１）又は（ｗ２）で表されるジアミン。(D) The diamine having the nitrogen-containing heterocycle described in [0173] to [0188] of WO2015 / 046374 and the diamine having the nitrogen-containing structure described in [0050] of Japanese Patent Application Laid-Open No. 2016-218149, the following formula (d). Diamine represented by BP),

(X is a biphenyl ring or a fluorene ring. Y is a group selected from a benzene ring, a biphenyl ring, or -Ph-Z-Ph-, Ph represents a phenylene group, and Z is -O-, -NH-. , -CH _2- , -SO _2- , -C (CH ₃ ) _2- or -C (CF ₃ ) _2-, which is a divalent group. A and B are hydrogen atoms or methyl groups. ), 2,3-Diaminopyridine, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 5,6-diamino-2,3-dicyanopyrazine, 5,6-diamino -2,4-dihydroxypyrimidine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 1,4-bis (3-aminopropyl) piperazine, 4,4'-[4,4' -Propane-1,3-diylbis (piperidine-1,4-diyl)] dianiline, 2,4-diamino-6-isopropoxy-1,3,5-triazine, 2,4-diamino-6-methoxy-1 , 3,5-triazine, 2,4-diamino-6-phenyl-1,3,5-triazine, 2,4-diamino-6-methyl-1,3,5-triazine, 2,4-diamino-1 , 3,5-triazine, 4,6-diamino-2-vinyl-1,3,5-triazine, 3,5-diamino-1,2,4-triazole, 6,9-diamino-2-ethoxyacridin lactate , 3,8-Diamino-6-phenylphenanthridine, 1,4-diaminopiperazin, 3,6-diaminoacridine, bis (4-aminophenyl) -N-phenylamine, 4,4'-diphenyl-N- Methylamine, 4,4'-diaminodiphenylamine, 3,6-diaminocarbazole, 9-methyl-3,6-diaminocarbazole, 9-ethyl-3,6-diaminocarbazole, according to the following formula (w1) or (w2). Represented diamine.

（Ｓｐは、フェニレン、ピロリジン、ピペリジン、ピペラジン、炭素数２〜２０の２価の鎖状炭化水素基、又は該２価の鎖状炭化水素基の−ＣＨ_２−が、−Ｏ−、−ＣＯ−、−ＣＯ−Ｏ−、−ＮＲＣＯ−（Ｒは水素原子又はメチル基を表す。）、−ＮＲＣＯＯ−（Ｒは水素原子又はメチル基を表す。）、−ＣＯＮＲ−（Ｒは水素原子又はメチル基を表す。）、−ＣＯＳ−、−ＮＲ−（Ｒはメチル基を表す。）、ピロリジン、ピペリジン、及びピペラジンから選ばれる基で置換された基を表す。）

(Sp is phenylene, pyrrolidine, piperidine, piperazine, a divalent chain hydrocarbon group having 2 to 20 carbon atoms, or -CH _{2- of the} divalent chain hydrocarbon group is -O-, -CO. -, -CO-O-, -NRCO- (R represents a hydrogen atom or a methyl group), -NRCOO- (R represents a hydrogen atom or a methyl group), -CONR- (R represents a hydrogen atom or a methyl group). Represents a group), -COS-, -NR- (R represents a methyl group), pyrrolidine, piperidine, and a group substituted with a group selected from piperazine.)

As _{a specific example of the diamine represented by the above formula (12) when Y 9} is a divalent organic group having -NH-CO-NH- in the molecule, A ₁ is represented by the following formula (13). _{-NH-CO-NH-, a group in which at least one of -CH 2- of} an alkylene group having 2 to 20 carbon atoms is substituted with -NH-CO-NH-, or an alkylene group having 2 to 20 carbon atoms. At least one of -CH _2- is replaced with -NH-CO-NH-, and _{at least one of the other -CH 2-} is -O-, -CO-, -CO-O-, -NRCO- ( R represents a hydrogen atom or a methyl group), -NRCOO- (R represents a hydrogen atom or a methyl group), -CONR- (R represents a hydrogen atom or a methyl group), -COS-, and- Examples thereof include diamine when the group is substituted with a group selected from NR- (R represents a methyl group). As a specific example of a more preferable diamine, a diamine represented by any of the following formulas (U-1) to (U-9).

（Ａ_１は単結合、−ＮＨ−ＣＯ−ＮＨ−、又は炭素数２〜２０のアルキレン基（但し、該アルキレン基の任意の−ＣＨ_２−は、−Ｏ−、−ＣＯ−、−ＣＯ−Ｏ−、−ＮＲＣＯ−（Ｒは水素原子又はメチル基を表す。）、−ＮＲＣＯＯ−（Ｒは水素原子又はメチル基を表す。）、−ＣＯＮＲ−（Ｒは水素原子又はメチル基を表す。）、−ＣＯＳ−、−ＮＲ−（Ｒはメチル基を表す）又は−ＮＨ−ＣＯ−ＮＨ−で置換されていてもよい。）を表す。Ａ_２は、ハロゲン原子、ヒドロキシ基、又は炭素数１〜５のアルキル基若しくはアルコキシ基（上記アルキル基若しくはアルコキシ基の任意の水素原子は、ハロゲン原子で置換されていてもよい。）を表す。ａは０〜４の整数であり、aが２以上の場合、Ａ_２は同一でも異なってもよい。ｂ及びｃは、１又は２の整数である。）

(A ₁ is a single bond, -NH-CO-NH-, or an alkylene group having 2 to 20 carbon atoms (provided that any -CH _{2- of the} alkylene group is -O-, -CO-, -CO-. O-, -NRCO- (R represents a hydrogen atom or a methyl group), -NRCOO- (R represents a hydrogen atom or a methyl group), -CONR- (R represents a hydrogen atom or a methyl group). , -COS-, -NR- (R represents a methyl group) or -NH-CO-NH- may be substituted. A ₂ is a halogen atom, a hydroxy group, or 1 carbon number. Represents an alkyl group or an alkoxy group of ~ 5 (any hydrogen atom of the above alkyl group or alkoxy group may be substituted with a halogen atom). A is an integer of 0 to 4, and a is 2 or more. In the case of, A ₂ may be the same or different. B and c are integers of 1 or 2.)

Preferred specific examples of the diamine represented by the above formula (w1) or (w2) include a diamine represented by any of the following formulas (n3-1) to (n3-7), and the following formula (n4-1). Examples thereof include diamines represented by any of (n4-6).

For the purpose of improving printability, a diamine having a carboxyl group (COOH group) or a hydroxyl group (OH group) can also be used. Specifically, 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 can be mentioned. Of these, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid or 3,5-diaminobenzoic acid is preferable. Further, a diamine represented by the following formulas [3b-1] to [3b-4], or a diamine in which these amino groups are secondary amino groups can also be used.

In the formula [3b-1], Q 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 independently represent integers 0-4, and m ¹ + m ² represent integers 1-4. In the formula [3b-2], m ³ and m ⁴ independently represent integers of 1 to 5. In the formula [3b-3], Q ² represents a linear or branched alkylene group having 1 to 5 carbon atoms, and m ⁵ represents an integer of 1 to 5. In the formula [3b-4], Q ³ and Q ⁴ are independently single-bonded, −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-, where m ⁶ is an integer of 1-4. )

As the diamine component for obtaining the second polyamic acid, a diamine used for obtaining the polymer (A) or a known diamine can be used in addition to the above. As the diamine component for obtaining the second polyamic acid, two or more kinds of diamines may be used in combination.

<Manufacturing method of polyamic acid, polyamic acid ester and polyimide>
The polyimide precursors polyamic acid ester, polyamic acid and polyimide used in the present invention can be produced, for example, by a known method as described in WO2013 / 157586.

<Liquid crystal alignment agent>
The liquid crystal alignment agent of the present invention may contain the polymer (A), a second polymer if desired, and further, other polymers in addition to these. Other 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. And so on.

The liquid crystal alignment agent is used for producing a liquid crystal alignment film, and takes the form of a coating liquid from the viewpoint of forming a uniform thin film. The liquid crystal alignment agent of the present invention is also preferably a coating liquid containing the above-mentioned polymer component and an organic solvent. At that time, the concentration (content) of the polymer in the liquid crystal alignment 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 concentration of the polymer is 2 to 8% by mass.

The organic solvent contained in the liquid crystal alignment agent is not particularly limited as long as it is a solvent (also referred to as a good solvent) in which the polymer component is uniformly dissolved. Specific examples thereof include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, γ-butyrolactone, 1,3-dimethyl. -2-imidazolidinone, methylethylketone, cyclohexanone, cyclopentanone, 3-methoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide and the like can be mentioned. Of these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N, N-dimethylpropanamide, 3-butoxy-N, N-dimethylpropanamide or γ-butyrolactone are preferable. The good solvent is preferably 20 to 99% by mass, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass, based on the total amount of the solvent contained in the liquid crystal alignment agent.

The organic solvent contained in the liquid crystal alignment agent is a mixture in which a solvent (also referred to as a poor solvent) that improves the coatability when the liquid crystal alignment agent is applied and the surface smoothness of the coating film is used in combination with a good solvent. It is preferable to use a solvent. Specific examples of the poor solvent are given below, but the present invention is not limited to these examples.
For example, diisopropyl ether, diisobutyl ether, diisobutylcarbinol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4- Methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol Diacetate, propylene carbonate, ethylene carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1- (2-butoxyethoxy) -2-propanol, 2- (2- (2-) Butoxyethoxy) -1-propanol, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetator , Diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2- (2-ethoxyethoxy) ethyl acetate, diethylene glycol acetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, 3- Methyl methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, diisobutyl ketone (2) , 6-Dimethyl-4-heptanone) and the like.

Among the poor solvents are 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, and ethylene glycol. Monobutyl ether, ethylene glycol monobutyl ether acetate and diisobutyl ketone are preferred.

Preferred solvent combinations of good and poor solvents 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 and 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, dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone And propylene glycol monobutyl ether and dipropylene glycol dimethyl ether and the like. 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 total amount of the solvent contained in the liquid crystal alignment agent. The type and content of such a solvent are appropriately selected depending on the coating device for the liquid crystal alignment agent, coating conditions, coating environment, and the like.

The liquid crystal alignment agent of the present invention may additionally contain a component other than the polymer component and the organic solvent. Such additional components include an adhesion aid for enhancing 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 for increasing the strength of the liquid crystal alignment film (hereinafter, cross-linking). (Also referred to as a sex compound), a dielectric for adjusting the dielectric constant and electrical resistance of the liquid crystal alignment film, a conductive substance, and the like can be mentioned.

（Ｒ_７１は、水素原子、炭素数１〜３のアルキル基又は「＊−ＣＨ_２−ＯＨ」である。Ｒ_７２及びＲ_７３は、それぞれ独立に水素原子、炭素数１〜３のアルキル基又は「＊−ＣＨ_２−ＯＨ」である。＊は結合手を示す。Ａは芳香環を有する（ｍ＋ｎ）価の有機基を表す。ｍは１〜６の整数を表し、ｎは０〜４の整数を表す。）The crosslinkable compound contains an oxylanyl group, an oxetanyl group, a protected isocyanate group, a protected isothiocyanate group, a group containing an oxazoline ring structure, and a meldramic acid structure from the viewpoint of less generation of AC afterimages and a high effect of improving film strength. A compound having at least one group selected from the group consisting of a group, a cyclocarbonate group, and a group represented by the following formula (d), or a compound represented by the following formula (e) (hereinafter collectively referred to as these). Compound (C)) is preferred.

(R ₇₁ is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or "* -CH _2- OH". R ₇₂ and R ₇₃ are independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms or an alkyl group having 1 to 3 carbon atoms, respectively. "* -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 0 to 4. Represents an integer.)

Specific examples of the compound having an oxylanyl group include two or more oxylanyls such as the compound described in [0037] of Japanese Patent Application Laid-Open No. 10-338880 and the compound having a triazine ring as a skeleton described in WO2017 / 170483. Examples include compounds having a group. Of these, N, N, N', N'-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N', N'-tetra Glycidyl-4, 4'-diaminodiphenylmethane, N, N, N', N'-tetraglycidyl-p-phenylenediamine, compounds represented by any of the following formulas (r-1) to (r-3), etc. Compounds containing the nitrogen atom of the above are particularly preferable.

Specific examples of the compound having an oxetanyl group include the compounds having two or more oxetanyl groups described in [0170] to [0175] of WO2011 / 132751.

Specific examples of the compound having a protected isocyanate group include the compounds having two or more protected isocyanate groups described in [0046] to [0047] of Japanese Patent Application Laid-Open No. 2014-224978, and [0119] to [0119] of WO2015 / 141598. Examples thereof include the compound having three or more protected isocyanate groups described in [0120]. 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 the compounds having two or more protected isothiocyanate groups described in Japanese Patent Application Laid-Open No. 2016-2000798.
Specific examples of the compound having a group containing an oxazoline ring structure include compounds containing two or more oxazoline structures described in [0115] of Japanese Patent Application Laid-Open No. 2007-286597.

Specific examples of the compound having a group containing a Meldrum's acid structure include the compound having two or more Meldrum's acid structures described in WO2012 / 091088.
Specific examples of the compound having a cyclocarbonate group include the compound described in WO2011 / 155577.
The _{R 1,} R 2, an alkyl group having 1 to 3 carbon atoms _{R 3} group represented by the above formula (d), a methyl group, an ethyl group, a propyl group.

Specific examples of the compound having a group represented by the above formula (d) include the group represented by the above formula (d) described in WO2015 / 072554 and Japanese Patent Application Laid-Open No. 2016-118753 [0058]. Examples thereof include compounds having two or more compounds, and compounds described in Japanese Patent Application Laid-Open No. 2016-2000798. Of 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 above formula (e) include an (m + n) -valent aromatic hydrocarbon group having 5 to 30 carbon atoms and an aromatic hydrocarbon group having 5 to 30 carbon atoms. Examples thereof include a (m + n) valent organic group 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 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, a benzimidazole ring, an indol ring, and a quinoxalin. Examples include a ring and an acridin ring. 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. Any hydrogen atom of the alkylene group may be substituted with an organic group such as a fluorine atom or a trifluoromethyl group. Specific examples include the compounds described in WO2010 / 074269. Preferred specific examples include any of the following formulas (e-1) to (e-9).

The above compound is an example of a crosslinkable compound, and is not limited thereto. For example, components other than the above disclosed in [0105] to [0116] of WO2015 / 060357 can be mentioned. Further, two or more kinds of crosslinkable compounds contained in the liquid crystal alignment agent of the present invention may be combined.
The content of the crosslinkable compound in the liquid crystal alignment agent of the present invention is preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent, and the crosslinking reaction proceeds. From the viewpoint of exhibiting the desired effect and generating less AC afterimage, the amount is more preferably 1 to 15 parts by mass.

Examples of the adhesion aid include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, and 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-trimethoxy Cyril-1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-dia Zanonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane Silane, 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-acryloxypropyltri Silane cups such as methoxysilane, tris- (trimethoxysilylpropyl) isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isoxapropyltriethoxysilane, etc. Ring agent can be mentioned. The amount of these silane coupling agents used is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 30 parts by mass with respect to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent, from the viewpoint of less generation of AC afterimages. 0.1 to 20 parts by mass.

<Manufacturing method of liquid crystal alignment film>
The liquid crystal alignment film using the liquid crystal alignment agent of the present invention can be produced by a known method for obtaining a liquid crystal alignment film from the liquid crystal alignment agent using the liquid crystal alignment agent of the present invention.
Among them, the liquid crystal alignment film using the liquid crystal alignment agent of the present invention is efficient by sequentially performing the following steps (1), step (2), step (3), and preferably the step (4). Can be manufactured in the same way.

<Process (1)>
This is a step of applying the liquid crystal alignment agent of the present invention onto a substrate. The substrate to which the liquid crystal alignment agent is applied is not particularly limited as long as it is a highly transparent substrate, and a glass substrate, a silicon nitride substrate, a plastic substrate such as an acrylic substrate or a polycarbonate substrate, or the like can be used. 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 reflective liquid crystal display element, an opaque object such as a silicon wafer can be used on one side of the substrate, and a material that reflects light such as aluminum can also be used for the electrode in this case.
Industrially, the method of applying the liquid crystal alignment agent is generally a method of screen printing, offset printing, flexographic printing, an inkjet method, or the like. Other coating methods include a dip method, a roll coater method, a slit coater method, a spinner method, a spray method, and the like, and these may be used depending on the purpose.

<Process (2)>
The step (2) is a step of heating the coating film of the liquid crystal alignment agent obtained in the step (1). After applying the liquid crystal alignment agent on the substrate, the solvent is evaporated by a heating means such as a hot plate, a heat circulation type oven or an IR (infrared) type oven, or the heat of the amic acid or the amic acid ester in the polymer is generated. It can be imidized. The drying and firing steps after applying the liquid crystal alignment agent can be performed at any temperature and time, and may be performed a plurality of times. The temperature at which the organic solvent of the liquid crystal alignment agent is removed can be, for example, 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, and examples thereof include 1 to 10 minutes or 1 to 5 minutes. When the amic acid or the amic acid ester in the polymer is thermally imidized, it can be calcined at, for example, 190 to 250 ° C. or 200 to 240 ° C. after the step of removing the organic solvent. The firing time is not particularly limited, and examples thereof include 5 to 40 minutes or 5 to 30 minutes.

<Process (3)>
The step (3) is a step of irradiating the film obtained in the step (2) with polarized ultraviolet rays. The wavelength of ultraviolet rays is preferably 200 to 400 nm, more preferably 200 to 300 nm. 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 dose of the radiation is preferably ^{1~10,000mJ / cm 2, 100~5,000mJ / cm} 2 is more preferable. The liquid crystal alignment film thus produced can stably orient the liquid crystal molecules in a certain direction.
The higher the extinction ratio of the polarized ultraviolet rays, the higher the anisotropy can be imparted, which is preferable. Specifically, the extinction ratio of linearly polarized ultraviolet rays is preferably 10: 1 or more, more preferably 20: 1 or more.

<Process (4)>
The step (4) is a step of firing the film obtained in the step (3) at 100 ° C. or higher and at a temperature higher than that of the step (2). The firing temperature is not particularly limited as long as it is 100 ° C. or higher and higher than the firing temperature in step (2), but is preferably 150 to 300 ° C., more preferably 150 to 250 ° C., and further preferably 200 to 250 ° C. preferable. The firing time is preferably 5 to 120 minutes, more preferably 5 to 60 minutes, and even more 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 5 to 300 nm is preferable, and 10 to 200 nm is more preferable.

Further, after performing any of the above steps (3) or (4), the obtained liquid crystal alignment film can be contact-treated with water and / or a solvent.
The solvent used for the contact treatment is not particularly limited as long as it is a solvent that dissolves the decomposition products 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. Of these, water, 2-propanol, 1-methoxy-2-propanol or ethyl lactate are preferable from the viewpoint of versatility and solvent safety. More preferred are water, 1-methoxy-2-propanol or ethyl lactate. Two or more kinds of solvents may be combined.

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

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

The liquid crystal alignment film of the present invention is suitable as a liquid crystal alignment film for a horizontal electric field type liquid crystal display element such as an IPS method or an FFS method, and is particularly useful as a liquid crystal alignment film for an FFS type liquid crystal display element. The liquid crystal display element is obtained by obtaining a substrate with a liquid crystal alignment film obtained from a liquid crystal alignment agent, then producing a liquid crystal cell by a known method, and using the liquid crystal cell.
As an example of a method for manufacturing a liquid crystal cell, a liquid crystal display element having a passive matrix structure will be described as an example. It should be noted that 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 constituting the image display may be used.

Specifically, a transparent glass substrate is prepared, and 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 as to display a desired image. Next, an insulating film is provided on each substrate so as to cover the common electrode and the segment electrode. The insulating film can be, for example, a film of _{SiO 2-} TiO _{2 formed by the sol-gel method.}
Next, a liquid crystal alignment film is formed on each substrate, the other substrate is superposed on one substrate so that the liquid crystal alignment film surfaces face each other, and the periphery is bonded with a sealant. In order to control the substrate gap, it is usually preferable to mix a spacer in the sealant, and it is preferable to spray the spacer for controlling the substrate gap also in the in-plane portion where the sealant is not provided. A part of the sealing agent is provided with an opening in which the liquid crystal can be filled from the outside. Next, the liquid crystal material is injected into the space surrounded by the two substrates and the sealant through the opening provided in the sealant, and then the opening is sealed with an adhesive. For injection, a vacuum injection method may be used, or a method utilizing capillarity 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, the 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.

As described above, by using the manufacturing method of the present invention, afterimages due to long-term AC drive generated in the liquid crystal display element of the IPS drive system or the FFS drive system can be suppressed. Further, in the step (2), the liquid crystal alignment film can be obtained in a smaller number of steps than in the conventional case by carrying out the step (3) after removing the organic solvent at 40 to 150 ° C. The liquid crystal alignment agent of the present invention can be particularly preferably used in a method for producing a liquid crystal alignment film, which comprises a step of removing the organic solvent at 40 to 150 ° C. in the step (2) and then carrying out the step (3).

As described above, by using the liquid crystal alignment agent of the present invention, it is possible to obtain a liquid crystal alignment film having less residual DC-derived afterimages and AC afterimages and having high seal adhesion. In particular, it is possible to obtain a liquid crystal display element having excellent contrast in which variation in brightness in the 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 measurement method of each characteristic in the following are as follows.
(solvent)
NMP: N-methyl-2-pyrrolidone, GBL: γ-butyrolactone,
BCS: Butyl cellosolve,
(Diamine)
DA-1 to DA-4: Compounds represented by the following formulas (DA-1) to (DA-4), respectively.
(Tetracarboxylic dianhydride)
CA-1, CA-2: Compounds (additives) represented by the following formulas (CA-1) and (CA-2), respectively.
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) ),

<Measurement of viscosity>
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 volume of 1.1 mL and a cone rotor TE-1 (1 ° 34', R24).

<Measurement of imidization rate>
20 mg of polyimide powder was placed in an NMR sample tube (NMR sampling tube standard, φ5 (manufactured by Kusano Kagaku Co., Ltd.)), and deuterated dimethyl sulfoxide (DMSO-d6, 0.05% TMS (tetramethylsilane) mixture) (0. 53 mL) was added and ultrasonically applied to completely dissolve. This solution was measured for proton NMR at 500 MHz with an NMR measuring machine (JNW-ECA500) (manufactured by JEOL Datum). The imidization rate is determined by using a proton derived from a structure that does not change before and after imidization as a reference proton, and the peak integrated value of this proton and the proton peak derived from the NH group of amic acid appearing in the vicinity of 9.5 ppm to 10.0 ppm. 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 integrated proton peak value derived from the NH group of amic acid, y is the integrated peak value of the reference proton, and α is one NH group proton of the amic acid in the case of polyamic acid (imidization rate is 0%). It is the number ratio of the reference protons to.

[Example of polymer synthesis]
Hereinafter, examples of synthesis of polyamic acid and polyimide will be shown. In addition, PI means that it is polyimide.

<Synthesis example 1>
In a 200 mL four-necked flask equipped with a stirrer and a nitrogen introduction tube, 7.33 g (0.03 mol) of DA-1 was weighed, 99.1 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. .. While stirring this diamine solution, 6.19 g (0.028 mol) of CA-1 was added, and the mixture was stirred at 40 ° C. for 24 hours to obtain a polyamic acid solution (A-1) (viscosity: 107 mPa · s).

<Synthesis example 2>
Weigh 4.10 g (0.0168 mol) of DA-1 and 8.32 g (0.0392 mol) of DA-3 in a 200 mL four-necked flask with a stirrer and a nitrogen inlet tube, and add 176 g of NMP. Then, nitrogen was sent and stirred to dissolve. While stirring this diamine solution, 11.6 g (0.0518 mol) of CA-1 was added, and the mixture was stirred at 40 ° C. for 24 hours to obtain a polyamic acid solution (A-2) (viscosity: 219 mPa · s).

<Synthesis example 3>
6.37 g (0.03 mol) of DA-3 was weighed in a 100 mL four-necked flask equipped with a stirrer and a nitrogen introduction tube, 92.3 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. .. 6.22 g (0.0278 mol) of CA-1 was added while stirring this diamine solution, and the mixture was stirred at 40 ° C. for 24 hours to obtain a polyamic acid solution (A-3) (viscosity: 347 mPa · s).

<Synthesis example 4>
Weigh 2.05 g (0.0084 mol) of DA-1 and 4.16 g (0.0196 mol) of DA-3 in a 100 mL four-necked flask with a stirrer and a nitrogen introduction tube, and 88. 6 g was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 5.52 g (0.0246 mol) of CA-1 and 0.35 g (0.0014 mol) of CA-2 were added, and the mixture was stirred at 40 ° C. for 24 hours to obtain a polyamic acid solution (A-). 4) (Viscosity: 213 mPa · s) was obtained.

<Synthesis Example 5>
Weigh 3.23 g (0.0084 mol) of DA-2 and 4.16 g (0.0196 mol) of DA-3 in a 200 mL four-necked flask with a stirrer and a nitrogen inlet tube, and 97. 3 g was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 5.52 g (0.0246 mol) of CA-1 and 0.35 g (0.0014 mol) of CA-2 were added, and the mixture was stirred at 40 ° C. for 24 hours to obtain a polyamic acid solution (A-). 5) (Viscosity: 198 mPa · s) was obtained.

<Synthesis example 6>
1.37 g (0.0056 mol) of DA-1, 4.16 g (0.0196 mol) of DA-3, and DA-4 in a 200 mL four-necked flask with a stirrer and a nitrogen inlet tube. 56 g (0.0028 mol) was weighed, 95.1 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 5.52 g (0.0246 mol) of CA-1 and 0.35 g (0.0014 mol) of CA-2 were added, and the mixture was stirred at 40 ° C. for 24 hours to obtain a polyamic acid solution (A-). 6) (Viscosity: 224 mPa · s) was obtained.

<Synthesis example 7>
1.37 g (0.0056 mol) of DA-1, 4.16 g (0.0196 mol) of DA-3, and DA-4 in a 200 mL four-necked flask with a stirrer and a nitrogen inlet tube. 56 g (0.0028 mol) was weighed, 95.3 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 5.21 g (0.0232 mol) of CA-1 and 0.700 g (0.0028 mol) of CA-2 were added, and the mixture was stirred at 40 ° C. for 24 hours to obtain a polyamic acid solution (A-). 7) (Viscosity: 177 mPa · s) was obtained.

<Synthesis Example 8>
1.37 g (0.0056 mol) of DA-1, 4.16 g (0.0196 mol) of DA-3, and DA-4 in a 200 mL four-necked flask with a stirrer and a nitrogen inlet tube. 56 g (0.0028 mol) was weighed, 95.6 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 4.90 g (0.0218 mol) of CA-1 and 1.05 g (0.0042 mol) of CA-2 were added, and the mixture was stirred at 40 ° C. for 24 hours to obtain a polyamic acid solution (A-). 8) (Viscosity: 176 mPa · s) was obtained.

<Synthesis example 9>
35 g (0.0093 mol) of the obtained polyamic acid solution (A-1) was taken in a 100 mL four-necked flask equipped with a stirrer and a nitrogen introduction tube, 11.7 g of NMP was added, and the mixture was stirred for 30 minutes. To the obtained polyamic acid solution, 2.84 g of acetic anhydride (3 equal to molar polyamic acid) and 0.73 g of pyridine (equal to molar polyamic acid) are added, and the mixture is heated at 50 ° C. for 3 hours for chemistry. Imidization was performed. The obtained reaction solution is poured into 150 ml of methanol with stirring, the precipitated precipitate is collected by filtration, the same operation is carried out twice to wash the resin powder, and then the resin powder is dried at 60 ° C. for 12 hours. Then, a polyimide resin powder was obtained. The imidization rate of this polyimide resin powder was 71%. Take 3.60 g of the obtained polyimide resin powder in a 100 ml Erlenmeyer flask, add 26.4 g of NMP so that the solid content concentration becomes 12%, and stir at 70 ° C. for 24 hours to dissolve the polyimide solution (A-1-. PI) was obtained.

<Synthesis Examples 10 to 16>
Other than using each raw material shown in Table 1 below, the same procedure was carried out using the method of Synthesis Example 9. The specifications of the polyimides obtained in Synthesis Examples 10 to 16 are shown in Table 1 together with Synthesis Example 9.

The numerical values in parentheses in Table 1 represent the compounding ratio (molar portion) of each compound to 100 mol parts of the total amount of the tetracarboxylic acid derivatives used for the synthesis for the tetracarboxylic acid component, and for the diamine component, for the synthesis. The compounding ratio (molar part) of each compound with respect to 100 mol part of the total amount of diamine used is shown. The organic solvent represents the mixing ratio (parts by mass) of each organic solvent with respect to 100 parts by mass of the total amount of the organic solvents contained in the polyamic acid solution or the polyimide solution.

[Preparation of liquid crystal alignment agent]
<Comparative Example 1>
7.5 g of polyimide solution (A-1-PI) is weighed in a 20 ml sample tube containing a stirrer, 2.23 g of NMP, 5.10 g of GBL, 4.0 g of BCS, and 1 of S-1. 0.90 g of GBL solution containing 10% by weight and 0.27 g of NMP solution containing 10% by weight of C-1 were added and stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal alignment agent (R1).

<Example 1>
7.5 g of polyimide solution (A-4-PI) was taken in a 20 ml sample tube containing a stirrer, 2.23 g of NMP, 5.10 g of GBL, 4.0 g of BCS, and 1% by weight of S-1. 0.90 g of the GBL solution containing the mixture and 0.27 g of the NMP solution containing 10% by weight of C-1 were added and stirred with a magnetic stirrer for 30 minutes to obtain a liquid crystal aligning agent (1).

<Examples 2 to 5, Comparative Examples 2 and 3>
In Examples 2 to 5 and Comparative Examples 2 and 3, the same steps as in Comparative Example 1 and Example 1 were carried out except that the polyimide solutions, additives and organic solvents shown in Table 2 below were used. A liquid crystal alignment agent was obtained. The specifications of each of the obtained liquid crystal alignment agents are shown in Table 1 together with the liquid crystal alignment agents of Example 1 and Comparative Example 1.

括弧内の数値は、液晶配向剤の合計量１００質量部に対する各成分の配合割合（質量％）を表す。

The numerical values in parentheses represent the mixing ratio (mass%) of each component with respect to 100 parts by mass of the total amount of the liquid crystal alignment agent.

<Manufacturing 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. An IZO electrode having a solid pattern, which constitutes a counter electrode as a first layer, is formed on the substrate. A SiN (silicon nitride) film formed by a CVD method is formed as a second layer on the counter electrode of the first layer. The film thickness of the SiN film of the second layer is 500 nm, and it functions as an interlayer insulating film. A comb-shaped pixel electrode formed by patterning an IZO film as a third layer is arranged on the SiN film of the second layer to form two pixels, a first pixel and a second pixel. ing. 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 by the action of the SiN film of the second layer.

The pixel electrode of the third layer has a comb-like shape formed by arranging a plurality of "dogleg" -shaped electrode elements having a bent central portion. The width of each electrode element in the lateral direction is 3 μm, and the distance between the electrode elements is 6 μm. Since the pixel electrodes forming each pixel are configured by arranging a plurality of bent "dogleg" shaped electrode elements in the central portion, the shape of each pixel is not rectangular, but is centered like the electrode elements. It has a shape similar to a bold "dogleg" that bends at a part. Then, each pixel is divided into upper and lower parts with a bent portion in the center as a boundary, and has a first region on the upper side and a second region on the lower side of the bent portion.

A liquid crystal alignment agent filtered through a filter having an average pore diameter of 1.0 μm is applied by spin coating on the front surface of each of the substrate with electrodes and the glass substrate having a columnar spacer having a height of 4 μm having an ITO film formed on the back surface. It was applied and dried on a hot plate at 80 ° C. for 2 minutes. Then, the coating film surface is irradiated with ultraviolet rays having a wavelength of 254 nm, which is linearly polarized with an extinction ratio of 26: 1 via a polarizing plate, at 150 to 350 mJ / cm ² , and then fired in a hot air circulation oven at 230 ° C. for 30 minutes to form a film. Each substrate with a liquid crystal alignment film having a thickness of 100 nm was obtained.
Next, a sealant was printed on one of the above set of glass substrates with a liquid crystal alignment film, the other substrate was bonded so that the liquid crystal alignment film surfaces faced each other, and the sealant was cured to prepare an empty cell. A liquid crystal MLC-3019 (manufactured by Merck Group) was injected into this empty cell by a vacuum 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]
<Evaluation of liquid crystal orientation>
Using the liquid crystal cell before ISO treatment, the one with the initial flow orientation was evaluated as "defective", and the one without the initial flow orientation was evaluated as "good".

<Evaluation of seal adhesion>
[Sample preparation]
The liquid crystal alignment agent prepared above was applied to 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 via a polarizing plate, and then baked in a hot air circulation oven at 230 ° C. for 20 minutes to apply a film thickness of 100 nm. A film was formed. The two substrates thus obtained were prepared, a 4 μm bead spacer was applied on the liquid crystal alignment film surface of one of the substrates, and then a sealing agent (XN-1500T manufactured by Kyoritsu Kagaku Sangyo Co., Ltd.) was dropped. Next, the liquid crystal alignment film surface of the other substrate was placed inside, and the substrates were bonded so that the overlapping width was 1 cm. At that time, the amount of the sealant dropped was adjusted so that the diameter of the sealant after bonding was 3 mm. After fixing the two bonded substrates with clips, they were heat-cured at 150 ° C. for 1 hour to prepare a sample for adhesion evaluation.

[Measurement of seal adhesion]
After fixing the end parts of the upper and lower boards with a desktop precision universal tester (AGS-X 500N, manufactured by Shimadzu Corporation), the sample board prepared above is pushed from the upper part of the center of the board and peeled off. The strength (N) at the time was measured. The value (peeling strength (N) / adhesive area (mm ² )) obtained by standardizing this peel strength (N) with the adhesive area (mm ² ) is defined as the seal adhesion (N / mm ² ) in each sample, and the seal adhesiveness. Was evaluated as "good" when it was larger than 4 N / mm ^2. When it was 4 N / mm ² or less, it was evaluated as "defective".

The liquid crystal alignment agent of the present invention is useful for forming a liquid crystal alignment film in a wide range of liquid crystal display elements such as an IPS drive system and an FFS drive system.
The entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2019-034305 filed on February 27, 2019 are cited here as the disclosure of the specification of the present invention. , Incorporate.

Claims (15)

It has a repeating unit represented by the following formula (1), a repeating unit represented by the following formula (2), a repeating unit represented by the following formula (3), and a repeating unit represented by the following formula (4). A liquid crystal alignment agent containing the polymer (A).

(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, and a fluorine atom. It is a monovalent organic group having 1 to 6 carbon atoms or a phenyl group, which may be the same or different, but _{at least one of R 1} to R ₄ represents a group other than the hydrogen atom in the above definition. Y _{1 represents a group other than the hydrogen atom.} Represents a divalent organic group having a partial structure represented by the following formula (H).)

(Q ³ is a structure represented by − (CH ₂ ) _n − (n is an integer of 2 to 20), and any −CH ₂ − is from −O− and −C (= O) −. It may be replaced with a group of choice, but the oxygen atoms do not bond directly to each other. Any hydrogen atom on the two benzene rings may be replaced with a monovalent organic group. * Is the bond. show.)

(X ₂ is a tetravalent organic group having an alicyclic structure of 5 members or more. Y ₂ represents a divalent organic group having a partial structure represented by the above formula (H)).

_{(R 31} to R ₃₄ in the formula (3) are _{synonymous with R 1} to R _{4 in} the above formula (1), respectively _{. X 4} in the formula (4) is synonymous with _{X 2 in the} above formula (2). Y ₃ and Y ₄ represent divalent organic groups represented by the following formula (I).)

(* Indicates a bond.) _{Claimed that X 2 of} the formula (2) _{or X 4 of the} formula (4) is a tetravalent organic group represented by any of the following formulas (X2-1) to (X2-12). The liquid crystal alignment agent according to 1.

_{Claimed that Y 1} and Y _{2 of the} formula (1) or (2) are divalent organic groups having a partial structure represented by any of the following formulas (H-1) to (H-7). Item 2. The liquid crystal alignment agent according to Item 1 or 2.

_{Claims 1 to 3 wherein Y 1} and Y _{2 of the} formula (1) or (2) are divalent organic groups represented by any of the following formulas (h-1) to (h-8). The liquid crystal alignment agent according to any one of the above.

The polymer (A) is the sum of the repeating units represented by the formula (1), the repeating units represented by the formula (2) and the formula (3), and the repeating unit represented by the formula (4). The liquid crystal alignment agent according to any one of claims 1 to 4, which is contained in an amount of 6 to 100 mol% with respect to all the repeating units of the coalescence (A). The polymer (A) contains 1 to 95 mol% of the total of the repeating unit represented by the formula (1) and the repeating unit represented by the formula (2) in an amount of 1 to 95 mol% with respect to all the repeating units, and the formula ( The liquid crystal according to any one of claims 1 to 5, which contains 5 to 99 mol of the total of the repeating unit represented by 3) and the repeating unit represented by the formula (4) with respect to all the repeating units. Orientation agent. The claim that the polymer (A) further has at least one kind of repeating unit selected from the group consisting of a repeating unit represented by the following formula (5) and a repeating unit represented by the following formula (6). The liquid crystal alignment agent according to any one of 1 to 6.

(R ₅₁ to R ₅₄ are synonymous with _{R 1} to R ₄ of the above formula (1) _{, respectively. Y 5} and Y ₆ each independently have a partial structure represented by the following formula (J-1). It represents a divalent organic group having or a divalent organic group represented by the following formula (J-2). X ₆ is synonymous with _{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 − (CH ₂ ) _n − is −O under the condition that any −CH ₂ − is not adjacent to each other. _{-, - COO -, - OCO} -, - NQ 9 -, - NQ 9 CO -, - CONQ 9 -, - NQ 9 CONQ 10 -, - NQ 9 COO-, or a group that is replaced in -OCOO-. Q ₉ and Q ₁₀ independently represent a hydrogen atom or a monovalent organic group. Q ₆ and Q ₇ independently represent -H, -NHD, -N (D) ₂ , and -NHD, respectively. group having or .Q ₈ represents a group having a -N _{(D) 2} represents a group having -NHD, _-N (D) 2, a group having a -NHD, or -N a _{(D) 2} .D Represents a carbamate-based protective group, where _{at least one of Q 5} , Q ₆ and Q ₇ has a carbamate-based protective group in the group. * 1 represents a bond. The partial structure represented by the formula (J-1) is the partial structure represented by any of the following formulas (J-1-a) to (J-1-d), according to claim 7. Liquid crystal alignment agent.

(Boc represents a tert-butoxycarbonyl group.) The polymer (A) has at least one type of repeating unit selected from the group consisting of the repeating unit represented by the formula (5) and the repeating unit represented by the formula (6). The liquid crystal alignment agent according to claim 7 or 8, which contains 1 to 40 mol% with respect to all repeating units. A liquid crystal alignment film obtained from the liquid crystal alignment agent according to any one of claims 1 to 9. A liquid crystal display element comprising the liquid crystal alignment film according to claim 10. A method for producing a liquid crystal alignment film, which comprises the following steps (1) to (3).
Step (1): A step of applying the liquid crystal alignment agent according to any one of claims 1 to 9 onto a substrate.
Step (2): A step of heating the coating film of the liquid crystal alignment agent obtained in the step (1).
Step (3): A step of irradiating the film obtained in step (2) with polarized ultraviolet rays. The method for producing a liquid crystal alignment film according to claim 12, further comprising the following step (4).
Step (4): A step of firing the film obtained in the step (3) at a temperature of 100 ° C. or higher and higher than that of the step (2). In the step (2), the coating film of the liquid crystal alignment agent is heated at a temperature of 40 to 180 ° C.
The method for producing a liquid crystal alignment film according to claim 12 or 13. A liquid crystal display element comprising the liquid crystal alignment film obtained by the method for producing a liquid crystal alignment film according to any one of claims 12 to 14.