JP2022003124A - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element using the same - Google Patents

Abstract

To provide: a liquid crystal alignment agent whereby a liquid crystal alignment film is obtained which has an excellent voltage holding ratio and fast relaxation of stored charge, and in which flickering is not prone to occur during driving thereof; a liquid crystal alignment film; and a liquid crystal display element.SOLUTION: A liquid crystal alignment agent is characterized by containing an organic solvent and a polymer obtained from a diamine having the structure represented by formula (1) (where, R1 and R2 are hydrogen atoms or monovalent organic groups; any hydrogen atom in a benzene ring may be substituted with an organic group; and * represents a bonding site).SELECTED DRAWING: None

Description

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

Liquid crystal display elements are widely used as display units for personal computers, mobile phones, smartphones, televisions, and the like. The liquid crystal display element 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, and an alignment film that controls the orientation of liquid crystal molecules in the liquid crystal layer. It is equipped with a thin film transistor (TFT) or the like for switching an electric signal supplied to a pixel electrode. 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 method are known. The horizontal electric field method in which electrodes are formed on only one side of the substrate and an electric field is applied in the direction parallel to the substrate is wider than the conventional vertical electric field method in which a voltage is applied to the electrodes formed on the upper and lower substrates to drive the liquid crystal display. It is known as a liquid crystal display element having a viewing angle characteristic and capable of high-quality display.

Although the transverse electric field type liquid crystal cell has excellent viewing angle characteristics, since there are few electrode portions formed in the substrate, if the voltage holding ratio is low, a sufficient voltage is not applied to the liquid crystal and the display contrast is lowered. Further, 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 an afterimage. Therefore, the stability of the liquid crystal orientation is important. Furthermore, static electricity is likely to be accumulated in the liquid crystal cell, and charges are accumulated in the liquid crystal cell even when a positive / negative asymmetric voltage generated by driving is applied, and these accumulated charges affect the display as a disorder of liquid crystal orientation or an afterimage. , The display quality of the liquid crystal element is significantly deteriorated. In addition, when the liquid crystal cell is irradiated with backlight light immediately after driving, electric charges are accumulated, afterimages are generated even after driving for a short time, and the size of flicker changes during driving. It will occur.

Patent Document 1 contains a specific diamine and an aliphatic tetracarboxylic acid derivative as a liquid crystal alignment agent having excellent voltage retention and reduced charge accumulation when used in such a transverse electric field type liquid crystal display element. The liquid crystal alignment agent to be used is disclosed. However, as the performance of the liquid crystal display element is improved, the characteristics required for the liquid crystal alignment film are becoming stricter, and it is difficult to fully satisfy all the required characteristics with these conventional techniques.

International Publication WO2004 / 021076 Pamphlet

The present invention provides a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element capable of obtaining a liquid crystal alignment film having excellent voltage retention, quick relaxation of accumulated charges, and less flicker during driving. That is the issue.

As a result of diligent studies to solve the above problems, the present inventors have found that various properties can be improved at the same time by introducing a specific structure into the polymer contained in the liquid crystal alignment agent. Completed the invention.

（式（１）中、Ｒ^１、Ｒ^２は、水素原子、又は一価の有機基である。ベンゼン環の任意の水素原子は一価の有機基で置換されていてもよい。＊は、結合部位を表す。）
２．前記重合体が、前記式（１）で表される構造を有するジアミンとテトラカルボン酸二無水物との重縮合物であるポリイミド前駆体及びそのイミド化物であるポリイミドからなる群から選ばれる少なくとも１種の重合体である前記1に記載の液晶配向剤。
３．前記ジアミンが、以下の式（２）で表される、前記１又は２に記載の液晶配向剤。

（式（２）中、Ｒ^１及びＲ^２の定義は、上記式（１）と同様であり、Ｒ³はそれぞれ独立して単結合又は以下の式（３）の構造を表し、ｎは１〜３の整数を表す。ベンゼン環の任意の水素原子は一価の有機基で置換されていてもよい。）

（式（３）中、Ｒ⁴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（２）中のベンゼン環と結合する部位を表し、＊_２は式（２）中のアミノ基と結合する部位を表す。）
４．前記ポリイミド前駆体が、下記式（４）で表される構造を有する、前記１〜３に記載の液晶配向剤。

（式（４）中、Ｘ_１はテトラカルボン酸誘導体に由来する４価の有機基であり、Ｙ_１は前記式（１）で表わされるジアミンに由来する２価の有機基であり、Ｒ₅は水素原子又は炭素数１〜５のアルキル基である。）
５．前記式（６）中、Ｘ_１が下記の（Ａ−１）〜（Ａ−２１）で表される構造からなる群から選ばれる少なくとも１種である、前記４に記載の液晶配向剤。
６．前記式（４）で表される構造単位を有する重合体が、液晶配向剤に含有される全重合体に対して１０モル％以上含有される前記４又は５に記載の液晶配向剤。
７．前記有機溶媒が、４−ヒドロキシ−４−メチル−２−ペンタノン及びジエチレングリコールジエチルエーテルからなる群から選ばれる少なくとも１種を含有する、前記１〜６のいずれか1項に記載の液晶配向剤。
８．前記１〜７のいずれか１項に記載の液晶配向剤を用いて得られる液晶配向膜。
９．前記８に記載の液晶配向膜を具備する液晶表示素子。
１０．液晶表示素子が横電界駆動方式である前記９に記載の液晶表示素子。
１１．下記式（１）で表される構造を有するジアミンとテトラカルボン酸二無水物との重縮合物であるポリイミド前駆体及びそのイミド化物であるポリイミドからなる群から選ばれる少なくとも１種の重合体。

（式（１）中、Ｒ^１、Ｒ^２は、水素原子、又は一価の有機基である。ベンゼン環の任意の水素原子は一価の有機基で置換されていてもよい。＊は、結合部位を表す。）
１２．上記ジアミンが、以下の式（２）で表される、前記１１に記載の重合体。

（式（２）中、Ｒ^１及びＲ^２の定義は、上記式（１）と同様であり、Ｒ³はそれぞれ独立して単結合又は以下の式（３）で表される構造を有し、ｎは１〜３の整数を表す。ベンゼン環の任意の水素原子は一価の有機基で置換されていてもよい。）

（式（３）中、Ｒ⁴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（２）中のベンゼン環と結合する部位を表し、＊_２は式（２）中のアミノ基と結合する部位を表す。）

（式（４）中、Ｘ_１はテトラカルボン酸誘導体に由来する４価の有機基であり、Ｙ_１は前記式（１）で表わされるジアミンに由来する２価の有機基であり、Ｒ₅は水素原子又は炭素数１〜５のアルキル基である。）
１４．前記式（６）中、Ｘ_１が下記の（Ａ−１）〜（Ａ−２１）で表される構造からなる群から選ばれる少なくとも１種である前記１３に記載の重合体。
１５．下記式（２）で表されるジアミン。

（式（２）中、Ｒ^１及びＲ^２の定義は、上記式（１）と同様であり、Ｒ³はそれぞれ独立して単結合又は以下の式（３）で表される構造を有し、ｎは１〜３の整数を表す。ベンゼン環の任意の水素原子は一価の有機基で置換されていてもよい。） The present invention is based on such findings, and has the following gist.
1. 1. A liquid crystal alignment agent containing a polymer obtained from a diamine having a structure represented by the following formula (1) and an organic solvent.

(In the formula (1), R ¹ and R ² are hydrogen atoms or monovalent organic groups. Any hydrogen atom in the benzene ring may be substituted with a monovalent organic group. Represents a binding site.)
2. 2. At least one selected from the group consisting of a polyimide precursor which is a polycondensate of a diamine having a structure represented by the formula (1) and a tetracarboxylic acid dianhydride and a polyimide which is an imidized product thereof. The liquid crystal alignment agent according to 1 above, which is a polymer of the species.
3. 3. The liquid crystal alignment agent according to 1 or 2 above, wherein the diamine is represented by the following formula (2).

(In the formula (2), ^{the definitions of R 1} and R ² are the same as those in the above formula (1), R ³ independently represents a single bond or the structure of the following formula (3), and n is 1. Represents an integer of ~ 3. Any hydrogen atom on the benzene ring may be substituted with a monovalent organic group.)

(In formula (3), R ⁴ is a single bond, -O- _{, -COO-, -OCO-,-(CH 2} ) _l- , -O (CH ₂ ) _m O-, -CONH-, and- A divalent organic group selected from NHCO-represents (l and m represent integers of 1 to 5), * ₁ represents a site that binds to a benzene ring in formula (2), and * ₂ represents a site of formula (2). ) Represents a site that binds to an amino group in.)
4. The liquid crystal alignment agent according to 1 to 3 above, wherein the polyimide precursor has a structure represented by the following formula (4).

(In the formula (4), X ₁ is a tetravalent organic group derived from a tetracarboxylic acid derivative, Y ₁ is a divalent organic group derived from a diamine represented by the above formula (1), and R ₅ Is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.)
5. _{The liquid crystal alignment agent according to 4 above, wherein X 1} is at least one selected from the group consisting of the structures represented by the following (A-1) to (A-21) in the formula (6).
6. The liquid crystal alignment agent according to 4 or 5, wherein the polymer having the structural unit represented by the formula (4) is contained in an amount of 10 mol% or more with respect to the total polymer contained in the liquid crystal alignment agent.
7. The liquid crystal alignment agent according to any one of 1 to 6 above, wherein the organic solvent contains at least one selected from the group consisting of 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether.
8. A liquid crystal alignment film obtained by using the liquid crystal alignment agent according to any one of 1 to 7 above.
9. A liquid crystal display element provided with the liquid crystal alignment film according to 8.
10. 9. The liquid crystal display element according to 9 above, wherein the liquid crystal display element is a transverse electric field drive system.
11. At least one polymer selected from the group consisting of a polyimide precursor which is a polycondensate of a diamine having a structure represented by the following formula (1) and a tetracarboxylic acid dianhydride and a polyimide which is an imidized product thereof.

(In the formula (1), R ¹ and R ² are hydrogen atoms or monovalent organic groups. Any hydrogen atom in the benzene ring may be substituted with a monovalent organic group. Represents a binding site.)
12. The polymer according to 11 above, wherein the diamine is represented by the following formula (2).

(In the formula (2), ^{the definitions of R 1} and R ² are the same as those in the above formula (1), and R ³ has a single bond independently or a structure represented by the following formula (3). , N represent an integer of 1-3. Any hydrogen atom of the benzene ring may be substituted with a monovalent organic group.)

(In equation (3), R ⁴ is a single bond, -O- _{, -COO-, -OCO-,-(CH 2} ) _l- , -O (CH ₂ ) _m O-, -CONH-, and- A divalent organic group selected from NHCO-represents (l and m represent integers of 1 to 5), * ₁ represents a site that binds to a benzene ring in formula (2), and * ₂ represents a site of formula (2). ) Represents a site that binds to an amino group in.)

(In the formula (4), X ₁ is a tetravalent organic group derived from a tetracarboxylic acid derivative, Y ₁ is a divalent organic group derived from a diamine represented by the above formula (1), and R ₅ Is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.)
14. _{The polymer according to 13 above, wherein X 1} is at least one selected from the group consisting of the structures represented by the following (A-1) to (A-21) in the formula (6).
15. A diamine represented by the following formula (2).

(In the formula (2), ^{the definitions of R 1} and R ² are the same as those in the above formula (1), and R ³ has a single bond independently or a structure represented by the following formula (3). , N represent an integer of 1-3. Any hydrogen atom of the benzene ring may be substituted with a monovalent organic group.)

According to the use of the liquid crystal alignment agent of the present invention, a liquid crystal alignment film in which accumulated charges are quickly relaxed and flicker is less likely to occur during driving, and a liquid crystal display element having excellent display characteristics are provided.
It is not clear why the above-mentioned problems can be solved by the invention of the present application, but it is generally considered as follows. The diamine represented by (1) above contained in the polymer contained in the liquid crystal alignment agent of the present invention has a structure in which a conductive pyrrole ring and a benzene ring are conjugated, and is formed by such a liquid crystal alignment agent. It is considered that this is because the liquid crystal alignment film facilitates the transfer of the charge applied when the element is driven, and can promote the relaxation of the accumulated charge.

<Specific diamine>
The liquid crystal alignment agent of the present invention contains a polymer obtained from a diamine having the structure of the following formula (1) (also referred to as a specific diamine in the present invention).

In the above formula (1), R ¹ and R ² are as defined above. Among them, R ¹ and R ² are preferably an alkyl group, an alkenyl group, an alkoxy group, a fluoroalkyl group, a fluoroalkoxy group, or a fluoroalkoxy group having 1 to 3 carbon atoms, and in particular, a hydrogen atom or a methyl group. Is preferable. Further, * represents a site that binds to an amino group, a substituted amino group, another organic group, or the like.

In the specific diamine, as shown in the following formula (1-1), the bond position of the two benzene rings with respect to the pyrrole ring is from the point of charge transfer, and at least one of them is next to the nitrogen atom on the pyrrole ring. It is preferably bonded to a carbon atom.

The specific diamine can be represented by, for example, the following formula (1-2), in particular, a diamine represented by the following formula (1-3) is preferable, and further, it is represented by the formula (1-4). Diamines are more preferred. In these equations, * represents the binding site.

In the formulas (1-2) to (1-4), ^{the definitions of R 1} and R ² are the same as in the case of the above formula (1), and Q ¹ and Q ² are independently single-bonded or It is a divalent organic group, that is, Q ¹ and Q ² may have different structures from each other. The two ^{Q 2} 'in the formula (1-4) may have a different structure from each other. Further, any hydrogen atom of the benzene ring may be substituted with a monovalent organic group as in the case of the above formula (1).

Preferred examples of the specific diamine include diamines represented by the following formula (2), and more preferably diamines represented by the formula (2-1).

（式（３）中、Ｒ⁴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（２）中のベンゼン環と結合する部位を表し、＊_２は式（２）中のアミノ基と結合する部位を表す。）
式（２）及び式（２−１）中、ｎは１〜３の整数を表す。好ましくは１又は２である。 In the formula (2), ^{the definitions of R 1} and R ² are the same as those in the above formula (1), R ³ independently represents a single bond or the structure of the following formula (3), and n is 1 to 1. Represents an integer of 3. Any hydrogen atom on the benzene ring may be substituted with a monovalent organic group.

(In equation (3), R ⁴ is a single bond, -O- _{, -COO-, -OCO-,-(CH 2} ) _l- , -O (CH ₂ ) _m O-, -CONH-, and- A divalent organic group selected from NHCO-represents (l and m represent integers of 1 to 5), * ₁ represents a site that binds to a benzene ring in formula (2), and * ₂ represents a site of formula (2). ) Represents a site that binds to an amino group in.)
In the formula (2) and the formula (2-1), n represents an integer of 1 to 3. It is preferably 1 or 2.

Specific examples of the diamine of the above formula (2) include, but are not limited to, the following. Above all, from the viewpoint of relaxation of accumulated charge, (2-1-1), (2-1-2), (2-1-3), (2-1-4), (2-1-5). , (2-1-8), (2-1-9), (2-1-10), (2-1-11) or (2-1-12), preferably (2-1-1). , (2-1-2), (2-1-3), (2-1-4), (2-1-5), (2-1-11) or (2-1-12) in particular. preferable.

（上記式２−１−６および式２−１−７中、ｎは１から５の整数を表す。）

(In the above equations 2-1-6 and 2-1-7, n represents an integer from 1 to 5.)

（Ｒ_１、Ｒ_２及びＲ_３水素、又は一価の有機基を表す。） <Synthesis method of specific diamine>
The method for synthesizing the specific diamine of the present invention is not particularly limited, and examples thereof include a method for synthesizing a dinitro compound represented by the following formula (1) and further reducing the nitro group to convert it into an amino group. ..

( _{Represents R 1} , R ₂ and R ₃ hydrogen, or a monovalent organic group)

The catalyst used for such a reduction reaction is preferably an activated carbon-supported metal available as a commercially available product, and examples thereof include palladium-activated carbon, platinum-activated carbon, and rhodium-activated carbon. Further, the catalyst does not necessarily have to be an activated carbon-supported metal catalyst such as palladium hydroxide, platinum oxide, and Raney nickel. In particular, palladium-activated carbon is preferable because it gives good results.
In order to proceed the reduction reaction more effectively, the reaction may be carried out in the coexistence of activated carbon. At this time, the amount of activated carbon used is not particularly limited, but is preferably in the range of 1 to 30% by mass, more preferably 10 to 20% by mass with respect to the dinitro compound. For the same reason, the reaction may be carried out under pressure. In this case, in order to avoid reduction of benzene nuclei, it is preferable to carry out in a pressurizing range up to 20 atm, and more preferably in a pressurizing range up to 10 atm.

The solvent can be used without limitation as long as it is a solvent that does not react with each raw material. For example, aprotic polar organic solvents (DMF, DMSO, DMAc, NMP, etc.); ethers _{(Et 2 O, i-Pr} 2 O, TBME, CPME, THF, dioxane, etc.), aliphatic hydrocarbons (pentane, Hexane, heptane, petroleum ether, etc.); Aromatic hydrocarbons (benzene, toluene, xylene, mesitylene, chlorobenzene, dichlorobenzene, nitrobenzene, tetralin, etc.); Halogen hydrocarbons (chloroform, dichloromethane, carbon tetrachloride, dichloroethane, etc.) Etc.); Lower fatty acid esters (methyl acetate, ethyl acetate, butyl acetate, methyl propionate, etc.); Nitriles (nitrile, propionitrile, butyronitrile, etc.); etc. can be used. These solvents can be appropriately selected in consideration of the susceptibility to reaction and the like, and two or more kinds of these solvents can be mixed and used. If necessary, the solvent can be dried with a suitable dehydrating agent or desiccant and used as a non-aqueous solvent.
The amount of the solvent used (reaction concentration) is preferably 0.1 to 10 times by mass, more preferably 0.5 to 30 times by mass, and particularly preferably 1 to 10 times by mass with respect to the dinitro compound. The reaction temperature is not particularly limited, but ranges from −100 ° C. to the boiling point of the solvent used, preferably −50 to 150 ° C. The reaction time is usually 0.05 to 350 hours, preferably 0.5 to 100 hours.

On the other hand, the method for synthesizing the nitro compound (A-1) is not particularly limited, but when the substitution positions of the amino group of the compound (A-1) are the 2-position and the 4-position, for example, the following formula (A-). It can be obtained by reacting the diamine represented by 2) with an aryl halide having a nitro group in the presence of a base and, if necessary, in the presence of an additive (X is F, Cl, Br, I, Or represents OTf.)

In the above aryl halide having a nitro group, if X is F or Cl and the NO ₂ group is at the 2-position or 4-position with respect to X, the aryl halide and the aliphatic are present in the presence of a base. The compound (A-1) can be obtained by reacting with an amine compound. The bases used are, for example, inorganic bases such as sodium hydrogen carbonate, potassium hydrogen carbonate, potassium phosphate, sodium carbonate, potassium carbonate, lithium carbonate, cesium carbonate, trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine, diisopropyl. Amines such as ethylamine, pyridine, quinoline, and colisine, sodium hydride, potassium hydride, and the like can be used. The reaction solvent and reaction temperature are in accordance with the above description. The product may be purified by recrystallization, distillation, silica gel column chromatography and the like.

If X is Br or I, the _two NO groups may be 2-position, 3-position or 4-position with respect to X, and the CN cross-coupling reaction should be used in the presence of a suitable metal catalyst, ligand, or base. But you can get a dinitro body. Examples of metal catalysts include palladium acetate, palladium chloride, palladium chloride-acetdium complex, palladium-activated carbon, bis (dibenzylideneacetone) palladium, tris (dibenzylideneacetone) dipalladium, bis (acet on) dichloropalladium, bis (benzo). Nitrile) Dichloropalladium, CuCl, CuBr, CuI, CuCN and the like can be mentioned, but the present invention is not limited thereto. Examples of ligands are triphenylphosphine, tri-o-trilphosphine, diphenylmethylphosphine, phenyldimethylphosphine, 1,2-bis (diphenylphosphine) ethane, 1,3-bis (diphenylphosphine) propane. , 1,4-Bis (diphenylphosphine) butane, 1,1'-bis (diphenylphosphine) ferrocene, trimethylphosphine, triethylphosphine, triphenylphosphine, tri-tert-butylphosphine and the like. , Not limited to these. As an example of the base, the above-mentioned base can be used. The reaction solvent and reaction temperature are in accordance with the above description. The product may be purified by recrystallization, distillation, silica gel column chromatography and the like.

Ｒ_１、Ｒ_３を導入するにあたっては、アミン類と反応が可能な化合物であればよく、例えば、酸ハライド、酸無水物、イソシアネート類、エポキシ類、オキセタン類、ハロゲン化アリール類、ハロゲン化アルキル類が挙げられる。また、アルコールの水酸基をOMs、ＯＴｆ、ＯＴｓ等の脱離基に置換したアルコール類などが使用できる。 The method for synthesizing the compound (A-2) is not particularly limited, but for example, a diamine represented by the following formula (A-3) is synthesized, and R ₁ and R ₃ are introduced into _{two NH groups.} There is a way to do it.

In _{introducing R 1} and R ₃ , any compound that can react with amines may be used, for example, acid halides, acid anhydrides, isocyanates, epoxys, oxetans, aryl halides, alkyl halides. Kind is mentioned. Further, alcohols in which the hydroxyl group of the alcohol is replaced with a leaving group such as OMs, OTf, OTs and the like can be used.

The method for introducing a monovalent organic group consisting of R ₁ and R _{3 into two} NH groups is not particularly limited, and examples thereof include a method in which an acid halide is reacted in the presence of an appropriate base. Examples of acid halides include acetyl chloroformate, chloroformate chloride, methyl chloroformate, ethyl chloroformate, n-propyl chloroformate, i-propyl chloroformate, n-butyl chloroformate, i-butyl chloroformate, t-chloroformate. Butyl, benzyl chloroformate, -9-fluorenyl chloroformic acid can be mentioned. As an example of the base, the above-mentioned base can be used. The reaction solvent and reaction temperature are in accordance with the above description.

_{R 1} and R ₃ may be introduced by _{reacting two} NH groups with an acid anhydride. Examples of acid anhydrides include acetic anhydride, propionic anhydride, dimethyl dicarbonate, diethyl dicarbonate, di-dicarbonate butyl dicarbonate, dibenzyl dicarbonate and the like. A catalyst may be used to accelerate the reaction, or pyridine, colidine, N, N-dimethyl-4-aminopyridine and the like may be used. The amount of catalyst is preferably 0.0001 to 1 mol with respect to the amount of (A-3) used. The reaction solvent and reaction temperature are in accordance with the above description.
_{R 1} may be introduced by _{reacting two} NH groups with isocyanates. Examples of isocyanates include methyl isocyanate, ethyl isocyanate, n-propyl isocyanate, phenyl isocyanate and the like. The reaction solvent and reaction temperature are in accordance with the above description.

_{R 1} and R ₃ may be introduced by _{reacting two} NH groups with epoxy compounds or oxetane compounds. Examples of epoxies and oxetane include ethylene oxide, propylene oxide, 1,2-butylene oxide, trimethylene oxide and the like. The reaction solvent and reaction temperature are in accordance with the above description.
_{R 1} and R ₃ may be introduced by reacting alcohols in which the hydroxyl group of the alcohol is replaced with a leaving group such as OMs, OTf, and OTs in the presence of an appropriate base on the NH _{2 group.} Examples of alcohols include methanol, ethanol, 1-propanol and the like. By reacting these alcohols with methanesulfonyl chloride, trifluoromethanesulfonyl chloride, paratoluenesulfonic acid chloride and the like, OMs and OTf are used. , OTs and the like can be substituted with a leaving group to obtain an alcohol. As an example of the base, the above-mentioned base can be used. The reaction solvent and reaction temperature are in accordance with the above description.

_{R 1} and R ₃ may be introduced by reacting an alkyl halide with an NH ₂ group in the presence of an appropriate base. Examples of alkyl halides include methyl iodide, ethyl iodide, n-propyl iodide, methyl bromide, ethyl bromide, n-propyl bromide and the like. As an example of the base, in addition to the above-mentioned base, metal alkoxides such as potassium-tert-butoxide and sodium-tert-butoxide can be used. The reaction solvent and reaction temperature are in accordance with the above description.

該反応に用いられる触媒、溶媒、温度は前記の記載に準ずる。 The method for synthesizing the compound (A-3) is not particularly limited, but a nitro compound represented by the following formula (4) is synthesized, and the nitro group contained in the nitro compound is further reduced to convert it into an amino group. There are ways to do this.

The catalyst, solvent, and temperature used for the reaction are in accordance with the above description.

該反応に用いられる酸の例としては、酢酸、ｐ−トルエンスルホン酸、ｐ-トルエンスルホン酸ピリジニウム等を用いることができるが、これらに限定されるものではない。反応溶媒、反応温度は、前記の記載に準ずる。 The method for synthesizing the compound (A-4) is not particularly limited, but the 1,4-diketone compound (A-5) represented by the following formula (5) and the primary amine are dehydrated under acidic conditions. It can be synthesized by condensing.

Examples of the acid used in the reaction include, but are not limited to, acetic acid, p-toluenesulfonic acid, pyridinium p-toluenesulfonic acid, and the like. The reaction solvent and reaction temperature are in accordance with the above description.

The method for synthesizing the compound (A-5) is not particularly limited, but the α-haloketone having a nitro group represented by the following formula (6) and the ketone having a nitro group are reacted in the presence of a base. (X represents Br, I or OTf).

As an example of the base used in the reaction, the above-mentioned base can be used. The reaction solvent and reaction temperature are in accordance with the above description. Additives can be used to accelerate the reaction rate. As the additive, zinc chloride, sodium iodide, potassium iodide, tetrabutylammonium iodide and the like can be used, but the additive is not limited thereto.

<Specific polymer>
The polymer of the present invention is a polymer obtained by using the above-mentioned specific diamine. Specific examples include polyamic acids, polyamic acid esters, polyimides, polyureas, and polyamides. Among them, from the viewpoint of use as a liquid crystal alignment agent, at least one polymer selected from a polyimide precursor containing a structural unit represented by the following formula (4) and a polyimide thereof, which is an imidized product thereof (hereinafter, specified. Also referred to as a polymer) is more preferable.

In the above formula (4), X ₁ is a tetravalent organic group derived from a tetracarboxylic acid derivative, and Y ₁ is a divalent organic group derived from a specific diamine. R ₅ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R ₅ is, from the viewpoint of the ease of imidization by heating, a hydrogen atom, a methyl group or an ethyl group.

The above X ₁ depends on the degree of required characteristics such as the solubility of the polymer in the solvent, the coatability of the liquid crystal alignment agent, the orientation of the liquid crystal when it is used as a liquid crystal alignment film, the voltage retention rate, and the accumulated charge. It may be appropriately selected, and two or more kinds may be used in the same polymer.
Specific examples of X ₁ include the structures of the formulas (X-1) to (X-46), which are published on pages 13 to 14 of International Publication 2015/111968.

Are shown below, but the preferred _{X 1 (A-1) ~} (A-21), but is not limited thereto.

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

<Other structural units>
The polyimide precursor may have a structural unit represented by the following formula (5) in addition to the structural unit represented by the formula (4).

In formula (5), X ₂ is the same as the definition in formula (4). Specific examples of X ₂ include those exemplified by _{X 1} of the formula (4), including preferable examples. R ₄ is the same as the definition in the above equation (4). It is preferable that at least one of twofold R ₄ is a hydrogen atom.

Further, Y ₂ is a divalent organic group derived from a diamine that does not contain the structure represented by the above formula (1) in the main chain direction, and its structure is not particularly limited. Y ₂ is appropriately determined according to the degree of required characteristics such as the solubility of the polymer in the solvent, the coatability of the liquid crystal alignment agent, the orientation of the liquid crystal when it is used as a liquid crystal alignment film, the voltage retention rate, and the accumulated charge. It may be selected and two or more kinds may be mixed in the same polymer.

If Specific examples of Y _2, the structure of the formulas listed in page 4 of WO 2015/119168 (2), and is posted on pages 8 to 12 pages, the formula (Y-1) ~ ( Structures of Y-97), (Y-101) to (Y-118); a divalent organic group obtained by removing two amino groups from the formula (2), which is published on page 6 of International Publication 2013/008696. A divalent organic group obtained by removing two amino groups from the formula (1) published on page 8 of International Publication 2015/122413; the formula (3) published on page 8 of International Publication 2015/060360. Structure: A divalent organic group obtained by removing two amino groups from the formula (1) described on page 8 of Japanese Patent Publication No. 2012-173514; the formula (A) published on page 9 of International Publication No. 2010-050523. )-(F), a divalent organic group obtained by removing two amino groups, and the like.

The preferred _{structure of Y 2} is shown below, but the present invention is not limited thereto.

Among the above structures, (B-28), (B-29) and the like are particularly preferable from the viewpoint of further improving the rubbing resistance, and (B-1) to (B-3) and the like are liquid crystal oriented. Particularly preferable from the viewpoint of further improvement, (B-14) to (B-18) and (B-27) are particularly preferable from the viewpoint of further improvement of the relaxation rate of the accumulated charge, and (B-26) and the like. Is preferable from the viewpoint of further improving the voltage retention rate.

When the polyimide precursor contains a structural unit represented by the formula (5) in addition to the structural unit represented by the formula (4), the structural unit represented by the formula (4) is the structural unit represented by the formula (4). It is preferably 10 mol% or more, more preferably 20 mol% or more, and particularly preferably 30 mol% or more with respect to the total of the formula (5).
The molecular weight of the polyimide precursor used in the present invention is preferably 2,000 to 500,000, more preferably 5,000 to 300,000, still more preferably 10,000 to 100,000 in terms of weight average molecular weight. be.

<Polyimide>
The polyimide among the specific polymers is obtained by ring-closing the polyimide precursors represented by the formulas (4) and (5). The imidization rate in this case does not necessarily have to be 100%, and can be arbitrarily adjusted according to the intended use and purpose.
As a method for imidizing the polyimide precursor, a known method can be used. Chemical imidization by adding a basic catalyst to the solution of the polyimide precursor is convenient. Chemical imidization is preferable because the imidization reaction proceeds at a relatively low temperature and the molecular weight of the polymer is unlikely to decrease during the imidization process.

Chemical imidization can be performed by stirring the polyimide precursor in an organic solvent in the presence of a basic catalyst. As the organic solvent, the solvent used in the above-mentioned polymerization reaction can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine and the like. Of these, triethylamine is preferable because it has sufficient basicity to allow the reaction to proceed.

The temperature at which the imidization reaction is carried out is -20 to 140 ° C., preferably 0 to 100 ° C., and the reaction time is preferably 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 mol times, preferably 2 to 20 mol times, that of the amic acid ester group. The imidization rate of the obtained polymer can be controlled by adjusting the amount of catalyst, temperature, reaction time and the like.

Since the added catalyst and the like remain in the solution after the imidization reaction of the polyimide precursor, the obtained imidized polymer is recovered by the means described below and redissolved in an organic solvent. It is preferable to use the liquid crystal alignment agent of the present invention.
That is, the polyimide solution obtained as described above can be injected into a poor solvent with good stirring to precipitate a polymer. Precipitation is carried out several times, and after washing with a poor solvent, it can be dried at room temperature or by heating to obtain a purified polyimide powder.
Examples of the poor solvent include, but are not limited to, methanol, acetone, hexane, butyl cellsolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene and the like.

<Liquid crystal alignment agent>
The liquid crystal alignment agent of the present invention contains a specific polymer, but may contain two or more specific polymers having different structures as long as the effects described in the present invention are exhibited. Further, in addition to the specific polymer, other polymers may be contained. 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, and poly (meth). ) Acrylate and the like can be mentioned. Further, it may contain a polyimide precursor represented by the above formula (5) and a polyimide selected from a polyimide obtained by imidizing the polyimide precursor.
When the liquid crystal alignment agent of the present invention contains other polymers, the ratio of the specific polymer to the total polymer components is preferably 5% by mass or more, more preferably 5 to 95% by mass.

The liquid crystal alignment agent is used for producing a liquid crystal alignment film, and generally 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 for dissolving the polymer component. At that time, the concentration 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, it is preferably 1% by mass or more, and from the viewpoint of storage stability of the solution, it is preferably 10% by mass or less. 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 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. -Imidazoridinone, methylethylketone, cyclohexanone, cyclopentanone and the like can be mentioned. Of these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ-butyrolactone is preferable.

As the organic solvent contained in the liquid crystal alignment agent, a mixed solvent is used in which a solvent that improves the coatability when the liquid crystal alignment agent is applied and the surface smoothness of the coating film is used in addition to the above-mentioned solvent. This is common, and such a mixed solvent is preferably used in the liquid crystal alignment agent of the present invention. Specific examples of the organic solvent used in combination are given below, but the present invention is not limited to these examples.

For example, ethanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentyl alcohol, tert-Pentyl alcohol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol , 2-Heptanol, 3-Heptanol, 1-Octanol, 2-Octanol, 2-Ethylene-1-hexanol, Cyclohexanol, 1-Methylcyclohexanol, 2-Methylcyclohexanol, 3-Methylcyclohexanol, 1,2- Ethylene diol, 1,2-propanediol, 1,3-propanediol, 1,2-butane diol, 1,3-butane diol, 1,4-butane diol, 2,3-butane diol, 1,5-pentane Dire, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, dipropyl ether, dibutyl ether, dihexyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-Butoxyetan, Diethylene glycol dimethyl ether, Diethylene glycol diethyl ether, 4-Hydroxy-4-methyl-2-pentanone, Diethylene glycol methyl ethyl ether, Diethylene glycol dibutyl ether, 2-Pentylene, 3-Pentanone, 2-Hexanone, 2-Heptanone , 4-Heptanone, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, 2- (methoxymethoxy) ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2- (hexyloxy) ethanol, furfuryl alcohol, diethylene glycol, propylene glycol, propylene glycol monobutyl ether, 1- ( Butoxyethoxy) propanol, propylene glycol monomethyl Ether acetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono Butyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2- (2-ethoxyethoxy) ethyl acetate, diethylene glycol acetate, triethylene glycol, tri Ethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate , 3-Ethoxypropionic acid methylethyl, 3-methoxypropionic acid ethyl, 3-ethoxypropionic acid, 3-methoxypropionic acid, 3-methoxypropionic acid propyl, 3-methoxypropionic acid butyl, lactic acid methyl ester, lactic acid ethyl ester, Examples thereof include lactic acid n-propyl ester, lactic acid n-butyl ester, lactic acid isoamyl ester, and solvents represented by the following formulas [D-1] to [D-3].

In the formula [D-1], D ¹ represents an alkyl group having 1 to 3 carbon atoms, and in the formula [D-2], D ² represents an alkyl group having 1 to 3 carbon atoms, and the formula [D-3]. Among them, D ³ represents an alkyl group having 1 to 4 carbon atoms. Among them, 1-hexanol, cyclohexanol, 1,2-ethanediol, 1,2-propanediol, propylene glycol monobutyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether or Dipropylene glycol dimethyl ether is preferred. 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, a cross-linking agent for increasing the strength of the liquid crystal alignment film, and a liquid crystal alignment. Examples thereof include a dielectric and a conductive substance for adjusting the dielectric constant and electric resistance of the film. Specific examples of these additional components are as disclosed in various known literatures on liquid crystal alignment agents. To give an example thereof, see pages 53 [0105] to 55 of International Publication No. 2015/060357 [ 0116] and the like.

<Liquid crystal alignment film>
The liquid crystal alignment film of the present invention is obtained from the liquid crystal alignment agent of the present invention. To give an example of a method of obtaining a liquid crystal alignment film from a liquid crystal alignment agent, a liquid crystal alignment agent in the form of a coating liquid is applied to a substrate, dried, and fired. The obtained film is subjected to a rubbing treatment method or a photoalignment treatment method. There is a method of performing orientation treatment with.
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 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 reflective liquid crystal display element, if only one side of the substrate is used, an opaque object such as a silicon wafer can be used, and in this case, a material that reflects light such as aluminum can also be used for the electrode.

The method for applying the liquid crystal alignment agent is not particularly limited, but industrially, screen printing, offset printing, flexographic printing, inkjet method and the like are common. 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.
After applying the liquid crystal alignment agent on the substrate, the solvent is evaporated and fired by a heating means such as a hot plate, a heat circulation type oven, or an IR (infrared) type oven. Any temperature and time can be selected for the drying and firing steps after applying the liquid crystal alignment agent. Usually, in order to sufficiently remove the contained solvent, a condition of firing at 50 to 120 ° C. for 1 to 10 minutes and then firing at 150 to 300 ° C. for 5 to 120 minutes can be mentioned.

The thickness of the liquid crystal alignment film after firing is not particularly limited, but if it is too thin, the reliability of the liquid crystal display element may decrease. Therefore, it is preferably 5 to 300 nm, more preferably 10 to 200 nm.
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.

<Liquid crystal display element>
In the liquid crystal display element of the present invention, after obtaining a substrate with a liquid crystal alignment film obtained from the liquid crystal alignment agent, a liquid crystal cell is produced by a known method, and the liquid crystal cell is used as an element.
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 made of SiO _2- TiO ₂ formed by the sol-gel method. Next, a liquid crystal alignment film is formed on each substrate under the above conditions.

Next, for example, an ultraviolet curable sealing material was placed at a predetermined place on one of the two substrates on which the liquid crystal alignment film was formed, and liquid crystal was further placed at a predetermined position on the liquid crystal alignment film surface. After that, the liquid crystal alignment film is spread over the entire surface of the liquid crystal alignment film by laminating and crimping the other substrate so that the liquid crystal alignment film faces each other, and then the entire surface of the substrate is irradiated with ultraviolet rays to cure the sealing material. Obtain a liquid crystal cell.
Alternatively, as a step after forming the liquid crystal alignment film on the substrate, when the sealing material is placed at a predetermined place on one of the substrates, an opening capable of filling the liquid crystal from the outside is provided to provide the liquid crystal. After the substrates are bonded together without being arranged, the liquid crystal material is injected into the liquid crystal cell through the opening provided in the sealing material, and then the opening is sealed with an adhesive to obtain a liquid crystal cell. The liquid crystal material may be injected by a vacuum injection method or a method using a capillary phenomenon in the atmosphere.

In any of the above methods, in order to secure a space for filling the liquid crystal material in the liquid crystal cell, a columnar protrusion is provided on one substrate, a spacer is sprayed on one substrate, or a sealing material is used. It is preferable to take measures such as mixing spacers in the liquid crystal display or combining them.

Examples of the liquid crystal material include nematic liquid crystal and smectic liquid crystal, and among them, nematic liquid crystal is preferable, and either positive type liquid crystal material or negative type liquid crystal material may be used. Next, the polarizing plate is installed. Specifically, it is preferable to attach a pair of polarizing plates to the surfaces of the two substrates opposite to the liquid crystal layer.
The liquid crystal alignment film and the liquid crystal display element of the present invention are not limited to the above description as long as the liquid crystal alignment agent of the present invention is used, and may be manufactured by other known methods. good. The process of obtaining a liquid crystal display element from a liquid crystal aligning agent is disclosed in, for example, paragraphs 0074 to 19 on page 17 of Japanese Patent Application Laid-Open No. 2015-135393 (Japanese Patent Laid-Open No. 2015-135393).

Hereinafter, the present invention will be specifically described with reference to examples and the like. The interpretation of the present invention is not limited to these examples.
The abbreviations of raw materials and the method for evaluating characteristics in the following are as follows.

<Organic solvent>
NMP: N-methyl-2-pyrrolidone,
NEP: N-ethyl-2-pyrrolidone GBL: γ-butyrolactone, BCS: butyl cellosolve PB: propylene glycol monobutyl ether DME: dipropylene glycol dimethyl ether DAA: 4-hydroxy-4-methyl-2-pentanone DEDG: diethylene glycol diethyl ether DIBK: 2,6-dimethyl-4-heptanone,
DIPE: diisopropyl ether,
DIBC: 2,6-dimethyl-4-heptanol,
Pd / C: Palladium carbon,
DMSO: Dimethyl sulfoxide, THF: Tetrahydrofuran <Additives>
LS-4668: 3-glycidoxypropyltriethoxysilane

<Crosslinking agent>

In the specification, Boc and Fmoc indicate a group represented by the following, and Me indicates a methyl group.

( ¹ Measurement of 1 H-NMR)
Equipment: Varian NMR system 400NB (400MHz) (manufactured by Varian), and JMTC-500 / 54 / SS (500MHz) (manufactured by JEOL)
Measuring solvent: CDCl ₃ (deuterated chloroform), DMSO-d ₆ (deuterated dimethyl sulfoxide)
Reference substance: TMS (tetramethylsilane) (δ: 0.0 ppm, ¹ H) and CDCl ₃ (δ: 77.0 ppm, ¹³ C)

(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 it. 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.

<Synthesis of diamine compound (DA-1)>

Zinc chloride (120.3 g, 882 mmol) was added to a 3 L (liter) four-necked flask, the temperature was raised to 100 ° C., and the mixture was vacuum dried in an oil pump for 1 hour. Then, at room temperature under a nitrogen atmosphere, toluene (460 g), diethylamine (45.0 g, 615 mmol), t-butanol (46.4 g, 626 mmol), 2-bromo-4-nitroacetophenone (100.0 g, 410 mmol), And 4-nitroacetophenone (104.2 g, 631 mmol) were sequentially added, and the mixture was stirred at room temperature for 3 days. After confirming the completion of the reaction by HPLC (high performance liquid chromatography), a 5% aqueous sulfuric acid solution (400 g) was added, neutralized, and the mixture was stirred at room temperature for 1 hour. The precipitated crystals were filtered under reduced pressure, washed successively with toluene (200 g), pure water (300 g), and methanol (200 g), and then dried to obtain crude crystals. The obtained crude crystals were completely dissolved in tetrahydrofuran (1340 g) at 60 ° C., ethanol (1340 g) was added, and the mixture was stirred at 5 ° C. for 1 hour. The precipitated crystals were filtered under reduced pressure, washed with ethanol (200 g), and then dried to obtain powder crystals (1) (yield 63 g, yield 45%).
1H-NMR (DMSO-d ₆ ): 8.40-8.36 (4H, m), 8.28-8.24 (4H, m), 3.53 (4H, s)

２Ｌの四つ口フラスコに化合物（１）（６５．８ｇ，２００ｍｍｏｌ）、酢酸アンモニウム（８４．５ｇ, １１００ｍｍｏｌ）、及び酢酸（８５５ｇ）を仕込み、１２０℃にまで昇温し、還流下にて３時間撹拌した。ＨＰＬＣ(高速液体クロマトグラフィ)にて反応終了を確認した後、反応液を冷水（４０００ｇ）に加え、1時間撹拌した。析出した結晶を減圧濾過し、アセトニトリル（１００ｇ）にてリパルプ洗浄した後、乾燥し、粉末結晶（２）を得た（収量５３ｇ，収率７８％）。
１Ｈ−ＮＭＲ（ＤＭＳＯ−ｄ_６）：１１．８（１Ｈ，ｂｒ），８．３０−８．２６（４Ｈ，ｍ），８．１１−８．０７（４Ｈ，ｍ），７．０４（２Ｈ，ｓ）

Compound (1) (65.8 g, 200 mmol), ammonium acetate (84.5 g, 1100 mmol), and acetic acid (855 g) were charged in a 2 L four-necked flask, heated to 120 ° C., and heated to 120 ° C. under reflux. Stir for hours. After confirming the completion of the reaction by HPLC (High Performance Liquid Chromatography), the reaction solution was added to cold water (4000 g) and stirred for 1 hour. The precipitated crystals were filtered under reduced pressure, washed with acetonitrile (100 g) and then dried to obtain powdered crystals (2) (yield 53 g, yield 78%).
1H-NMR (DMSO-d ₆ ): 11.8 (1H, br), 8.30-8.26 (4H, m), 8.11-8.07 (4H, m), 7.04 (2H) , S)

１Ｌの四つ口フラスコに化合物（２）（４１．３ｇ，１３４ｍｍｏｌ）、炭酸カリウム（２７．８ｇ，２０１ｍｍｏｌ）、及びジメチルホルムアミド（５４０ｇ）を仕込み、室温にてヨウ化メチル（３８．１ｇ，２６８ｍｍｏｌ）を滴下し、２４時間撹拌した。ＨＰＬＣ(高速液体クロマトグラフィ)にて反応終了を確認した後、反応液を冷水（４３００ｇ）に加え、１時間撹拌した。析出した結晶を減圧濾過し、２−プロパノール（１００ｇ）にて洗浄した後、乾燥し、粉末結晶（３）を得た（収量４１．１ｇ，収率９０％）。
１Ｈ−ＮＭＲ（ＤＭＳＯ−ｄ_６）：８．３４−８．３３（４Ｈ，ｍ），７．８６−７．８１（４Ｈ，ｍ），６．６７（２Ｈ，ｓ），３．７３（３Ｈ，ｓ）

Compound (2) (41.3 g, 134 mmol), potassium carbonate (27.8 g, 201 mmol), and dimethylformamide (540 g) were charged in a 1 L four-necked flask, and methyl iodide (38.1 g, 268 mmol) was charged at room temperature. ) Was added dropwise, and the mixture was stirred for 24 hours. After confirming the completion of the reaction by HPLC (High Performance Liquid Chromatography), the reaction solution was added to cold water (4300 g) and stirred for 1 hour. The precipitated crystals were filtered under reduced pressure, washed with 2-propanol (100 g), and then dried to obtain powder crystals (3) (yield 41.1 g, yield 90%).
1H-NMR (DMSO-d ₆ ): 8.34-8.33 (4H, m), 7.86-7.81 (4H, m), 6.67 (2H, s), 3.73 (3H) , S)

化合物（３）（４０ｇ、１２４ｍｍｏｌ）、５質量％Ｐｄ／Ｃ（５０％含水型）、特級白鷺活性炭（４．０ｇ）、及びジオキサン(４００ｇ)の混合物を、水素加圧条件下に８０℃で８時間攪拌した。反応終了後、触媒をろ過した後、濃縮を行い、２−プロパノール（４００ｇ）を加え、５℃にて1時間撹拌した。析出した結晶を減圧濾過し、２−プロパノール（１００ｇ）で洗浄した後、乾燥し、粉末結晶（４）を得た（収量１７ｇ，収率５２％）。
１Ｈ−ＮＭＲ（ＤＭＳＯ−ｄ_６）：７．１１−７．０８（４Ｈ，ｍ），６．６３−６．５９（４Ｈ，ｍ），５．９６（２Ｈ，ｓ），５．１５（４Ｈ，ｓ），３．４３（３Ｈ，ｓ）

A mixture of compound (3) (40 g, 124 mmol), 5 mass% Pd / C (50% water-containing type), special grade Shirasagi activated carbon (4.0 g), and dioxane (400 g) at 80 ° C. under hydrogen pressurization conditions. The mixture was stirred for 8 hours. After completion of the reaction, the catalyst was filtered, concentrated, 2-propanol (400 g) was added, and the mixture was stirred at 5 ° C. for 1 hour. The precipitated crystals were filtered under reduced pressure, washed with 2-propanol (100 g), and then dried to obtain powder crystals (4) (yield 17 g, yield 52%).
1H-NMR (DMSO-d ₆ ): 7.11-7.08 (4H, m), 6.63-6.59 (4H, m), 5.96 (2H, s), 5.15 (4H) , S), 3.43 (3H, s)

１Ｌの四つ口フラスコに化合物（４）（２７．４ｇ，１０４ｍｍｏｌ）及びＴＨＦ（２７０ｇ）を仕込み、氷冷下にてトリフルオロ酢酸無水物（４６．５ｇ, ２２０ｍｍｏｌ）を滴下し、１時間撹拌した。ＨＰＬＣ(高速液体クロマトグラフィ)にて反応終了を確認した後、濃縮乾固した。得られた固体に対し、ＴＨＦ（６００ｇ）、炭酸カリウム（４５．１ｇ，３２６ｍｍｏｌ）を加え、室温にてヨウ化メチル（４５．８ｇ，３２４ｍｍｏｌ）を滴下し、４０℃にて２２時間撹拌した。ＨＰＬＣ(高速液体クロマトグラフィ)にて反応終了を確認した後、塩を減圧濾過にて除去し、濃縮乾固した。

Compound (4) (27.4 g, 104 mmol) and THF (270 g) are charged in a 1 L four-necked flask, trifluoroacetic anhydride (46.5 g, 220 mmol) is added dropwise under ice-cooling, and the mixture is stirred for 1 hour. did. After confirming the completion of the reaction by HPLC (High Performance Liquid Chromatography), the mixture was concentrated to dryness. THF (600 g) and potassium carbonate (45.1 g, 326 mmol) were added to the obtained solid, methyl iodide (45.8 g, 324 mmol) was added dropwise at room temperature, and the mixture was stirred at 40 ° C. for 22 hours. After confirming the completion of the reaction by HPLC (High Performance Liquid Chromatography), the salt was removed by vacuum filtration and concentrated to dryness.

N-Methylpyrrolidone (200 g), pure water (30 g), and potassium hydroxide (20.8 g, 315 mmol) were added to the obtained solid, and the mixture was stirred at 60 ° C. for 30 minutes. After confirming the completion of the reaction by HPLC (high performance liquid chromatography), the reaction solution was added to cold water (1200 g), and the mixture was stirred for 1 hour. The precipitated crystals were filtered under reduced pressure, washed with 2-propanol (100 g), and then dried to obtain powder crystals (5) (yield 22.9 g, yield 76%).
1H-NMR (DMSO-d ₆ ): 7.20-7.17 (4H, m), 6.60-6.57 (4H, m), 5.99 (2H, s), 5.73 (2H) , Q), 3.45 (3H, s), 2.70 (6H, d)

１Ｌの四つ口フラスコに水素化ナトリウム（１９．７ｇ, ４９４ｍｍｏｌ）及びＮ−メチルピロリドン（２０ｇ）を加え、氷冷した。これに対し、窒素フロ―下、化合物（５）（２２．９ｇ, ７８．７ｍｍｏｌ）及びＮ−メチルピロリドン（１１５ｇ）の溶液をゆっくりと滴下した後、次いで、4-フルオロニトロベンゼン（４４．４ｇ、３１５ｍｍｏｌ）及びＮ−メチルピロリドン（４４ｇ）の溶液を滴下し、室温にて２４時間撹拌した。

Sodium hydride (19.7 g, 494 mmol) and N-methylpyrrolidone (20 g) were added to a 1 L four-necked flask, and the mixture was ice-cooled. In contrast, a solution of compound (5) (22.9 g, 78.7 mmol) and N-methylpyrrolidone (115 g) was slowly added dropwise under nitrogen flow, followed by 4-fluoronitrobenzene (44.4 g, 44.4 g,). A solution of 315 mmol) and N-methylpyrrolidone (44 g) was added dropwise and stirred at room temperature for 24 hours.

After confirming the completion of the reaction by HPLC (High Performance Liquid Chromatography), the reaction solution was added to cold water (1800 g) and stirred for 1 hour. The obtained crude crystals were repulped with tetrahydrofuran (450 g), filtered under reduced pressure, washed with methanol (100 g) and dried to obtain powder crystals (6) (yield 22.7 g, yield 54%). ).
1H-NMR (DMSO-d ₆ ): 8.09 (4H, d), 7.64 (4H, d), 7.42 (4H, d), 6.87 (4H, d), 6.37 ( 2H, s), 3.69 (3H, s), 3.44 (6H, s),

化合物（６）（２２．７ｇ、４２．６ｍｍｏｌ）、５質量％Ｐｄ／Ｃ（５０％含水型）、特性白鷺活性炭（２．０ｇ）、及びジオキサン(２３０ｇ)の混合物を、水素加圧条件下に８０℃で８時間攪拌した。反応終了後、触媒をろ過した後、濃縮を行い、２−プロパノール（３００ｇ）を加え、５℃にて1時間撹拌した。析出した結晶を減圧濾過し、２−プロｐノール（１００ｇ）で洗浄した後、乾燥し、粉末結晶（ＤＡ−１）を得た（収量１７．４ｇ，収率８６％）。
１Ｈ−ＮＭＲ（ＤＭＳＯ−ｄ_６）：７．２０（４Ｈ，ｄ），６．８９（４Ｈ，ｄ），６．６７−６．５９（８Ｈ，ｍ），６．０２（２Ｈ，ｓ），５．０６（４Ｈ，ｓ），３．４６（３Ｈ，ｓ），３．１７（６Ｈ，ｓ），

A mixture of compound (6) (22.7 g, 42.6 mmol), 5% by mass Pd / C (50% water-containing type), characteristic Shirasagi activated carbon (2.0 g), and dioxane (230 g) was subjected to hydrogen pressurization conditions. Was stirred at 80 ° C. for 8 hours. After completion of the reaction, the catalyst was filtered, concentrated, 2-propanol (300 g) was added, and the mixture was stirred at 5 ° C. for 1 hour. The precipitated crystals were filtered under reduced pressure, washed with 2-propanol (100 g), and then dried to obtain powder crystals (DA-1) (yield 17.4 g, yield 86%).
1H-NMR (DMSO-d ₆ ): 7.20 (4H, d), 6.89 (4H, d), 6.67-6.59 (8H, m), 6.02 (2H, s), 5.06 (4H, s), 3.46 (3H, s), 3.17 (6H, s),

[Synthesis Example 1]
After adding DA-1 (1.99 g, 4.2 mmol) to a 100 ml four-necked flask with a stirrer and a nitrogen introduction tube, 20.0 g of a mixed solvent of NMP: GBL = 1: 1 (mass ratio). Was added, and the mixture was stirred and dissolved while feeding nitrogen. After adding 8.0 g of CA-1 (0.61 g, 2.8 mmol), CA-2 (0.73 g, 3.7 mmol), and NMP: GBL = 1: 1 mixed solvent while stirring this solution. Further, the mixture was further stirred at 50 ° C. for 12 hours to obtain a polyamic acid solution (PAA-A1).

[Synthesis Examples 2 to 6]
The polyamic acid solution (PAA-A2) and the polyamic acid solution (PAA-B1) were carried out in the same manner as in Synthesis Example 1 except that the diamine component, the tetracarboxylic acid component and the solvent shown in Table 1 were used. -(PAA-B4) was obtained.

[Synthesis Example 7]
DA-6 (4.03 g, 16.5 mmol), DA-7 (3.59 g, 9.0 mmol), and DA-8 (2.51 g) in a 200 ml four-necked flask with a stirrer and a nitrogen inlet tube. , 4.5 mmol), then 74.0 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this solution, CA-4 (4.37 g, 19.5 mmol) and 9.0 g of NMP were added, and the mixture was stirred under the condition of 40 ° C. for 3 hours. Then, under the condition of 25 ° C., CA-2 (1.71 g, 8.7 mmol) and 9.0 g of NMP were added, and then the mixture was further stirred for 12 hours to obtain a polyamic acid solution.

80.0 g of this polyamic acid solution was taken, 20.0 g of NMP was added, 6.8 g of acetic anhydride and 1.8 g of pyridine were added, and the mixture was reacted at 50 ° C. for 3 hours. This reaction solution was added to 434.4 g of methanol with stirring, and the precipitated precipitate was separated by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 ° C. to obtain a polyimide powder. The imidization rate of this polyimide was 75%. A polyimide solution (SPI-B5) was obtained by adding 80.0 g of NMP to 20.0 g of the obtained polyimide powder and stirring at 70 ° C. for 20 hours to dissolve it.

[Synthesis Example 8]
Weigh DA-5 (68.5 g, 280 mmol) and DA-8 (23.9 g, 70 mmol) in a 1000 mL four-necked flask with a stirrer and a nitrogen inlet tube, add 586 g of NMP, and add nitrogen. Was stirred and dissolved while feeding. CA-4 (74.5 g, 332 mmol) was added while stirring this solution, NMP was further added so that the solid content concentration became 18% by mass, and the mixture was stirred at room temperature for 24 hours to obtain a polyamic acid solution.
200 g of this polyamic acid solution was weighed, 100 g of NMP was added, and the mixture was stirred for 30 minutes. To the obtained polyamic acid solution, 21.78 g of acetic anhydride and 2.81 g of pyridine were added, and the mixture was reacted at 60 ° C. for 3 hours. The obtained reaction solution was added to 624.2 g of methanol with stirring, and the precipitated precipitate was separated by filtration. The precipitate was washed with methanol and dried under reduced pressure at 60 ° C. to obtain a polyimide powder. The imidization rate of this polyimide was 68%. A polyimide solution (SPI-B6) was obtained by adding 239.8 g of NMP to 32.7 g of the obtained polyimide powder and stirring at 70 ° C. for 20 hours to dissolve the powder.

[Examples 1 to 12] and [Comparative Examples 1 to 7]
The solvent and the additive were stirred while stirring the polyamic acid solution obtained in Synthesis Examples 1 to 6 and the polyimide solution obtained in Synthesis Examples 7 and 8 so as to have the compositions shown in Tables 2 and 3, respectively. Was added, and the mixture was further stirred at room temperature for 2 hours to obtain liquid crystal alignment agents of Examples 1 to 12 and Comparative Examples 1 to 7.
In Tables 2 and 3, * 1 and * 2 indicate the content (addition) amount (parts by mass) with respect to 100 parts by mass of all the polymers, and * 3 indicates the use of a solvent with respect to 100 parts by mass of the liquid crystal alignment agent. Indicates the amount (parts by mass).

<Manufacturing of liquid crystal display element by rubbing method>
A glass substrate with an electrode having a size of 30 mm in length × 35 mm in width and a thickness of 0.7 mm was prepared. 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 (FIG. 3 of Japanese Patent Application Laid-Open No. 2014-77745). reference). 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.

Comparing the first region and the second region of each pixel, the forming directions of the electrode elements of the pixel electrodes constituting them are different. That is, when the rubbing direction of the liquid crystal alignment film described later is used as a reference, the electrode elements of the pixel electrodes are formed so as to form an angle (clockwise) of + 10 ° in the first region of the pixel, and the pixel is formed in the second region of the pixel. The electrode elements of the electrodes are formed so as to form an angle of −10 ° (clockwise). Further, in the first region and the second region of each pixel, the directions of the rotation operation (inplane switching) of the liquid crystal in the substrate surface induced by the voltage application between the pixel electrode and the counter electrode are mutual. It is configured to be in the opposite direction.

Next, after filtering the liquid crystal alignment agent with a filter having a pore size of 1.0 μm, an ITO film is formed on the back surface of the substrate with electrodes as a facing substrate, and a glass substrate having a columnar spacer having a height of 4 μm is formed. Each was spin coated. Then, it was dried on a hot plate at 80 ° C. for 5 minutes and then fired at 230 ° C. for 20 minutes to obtain a polyimide film having a film thickness of 60 nm on each substrate. The polyimide film surface is rubbed with a rayon cloth under the conditions of a roll diameter of 120 mm, a roller rotation speed of 500 rpm, a stage moving speed of 30 mm / sec, and a rubbing cloth pushing pressure of 0.3 mm, and then in pure water for 1 minute. Ultrasonic irradiation was performed and the mixture was dried at 80 ° C. for 10 minutes.
Using the above two types of substrates with a liquid crystal alignment film, they were combined so that their rubbing directions were antiparallel, and the surroundings were sealed leaving the liquid crystal injection port, to produce an empty cell with a cell gap of 3.8 μm. .. A liquid crystal (MLC-3019 manufactured by Merck Group) was vacuum-injected into this empty cell at room temperature, and then the injection port was sealed to obtain an anti-parallel oriented liquid crystal cell. The obtained liquid crystal cell constitutes an FFS mode liquid crystal display element. Then, the liquid crystal cell was heated at 120 ° C. for 1 hour, left overnight, and then used for evaluation.

<Evaluation of afterimage erasure time>
The produced liquid crystal cell is placed between two polarizing plates arranged so that the polarization axes are orthogonal to each other, and the LED backlight is turned on in a state where no voltage is applied so that the brightness of the transmitted light is minimized. The arrangement angle of the liquid crystal cell was adjusted. Next, the VT curve (voltage-transmittance curve) was measured while applying an AC voltage having a frequency of 30 Hz to the liquid crystal cell, and the AC voltage having a relative transmittance of 23% was calculated as the drive voltage.
In the afterimage evaluation, an AC voltage having a frequency of 30 Hz having a relative transmittance of 23% was applied to drive the liquid crystal cell, and at the same time, a DC voltage of 1 V was applied to drive the liquid crystal cell for 30 minutes. After that, the applied DC voltage value was set to 0 V, only the application of the DC voltage was stopped, and the vehicle was driven for another 15 minutes in that state.

In the afterimage evaluation, the time during which the relative transmittance decreased to 30% or less was quantified from the time when the application of the DC voltage was started until 30 minutes had elapsed. When the relative transmittance decreased to 30% or less within 5 minutes, it was evaluated as “◯”, and when it was within 6 to 30 minutes, it was evaluated as “Δ”. When it took 30 minutes or more for the relative transmittance to decrease to 30% or less, the afterimage could not be erased and evaluated as "x". Then, the afterimage evaluation according to the above-mentioned method was performed under the temperature condition in which the temperature of the liquid crystal cell was 23 ° C.

<Evaluation of flicker shift that occurs immediately after the start of driving>
The produced liquid crystal cell is placed between two polarizing plates arranged so that the polarization axes are orthogonal to each other, and the LED backlight is turned on in a state where no voltage is applied so that the brightness of the transmitted light is minimized. The arrangement angle of the liquid crystal cell was adjusted. Next, the VT curve (voltage-transmittance curve) was measured while applying an AC voltage having a frequency of 30 Hz to the liquid crystal cell, and the AC voltage having a relative transmittance of 23% was calculated as the drive voltage.

In the measurement of the flicker level, the LED backlight that has been turned on is turned off and left for 72 hours, then the LED backlight is turned on again, and the relative transmission rate becomes 23% at the same time as the backlight starts lighting. The AC voltage was applied and the liquid crystal cell was driven for 60 minutes to track the flicker amplitude. The flicker amplitude is a data acquisition / data logger switch unit 34970A (Agilent technologies) in which the transmitted light of the LED backlight that has passed through the two polarizing plates and the liquid crystal cell between them is connected via a photodiode and an IV conversion amplifier. I read it with (manufactured by the company). The flicker level was calculated by the following formula.
Flicker level (%) = {flicker amplitude / (2 × z)} × 100

In the above formula, z is a value read by the data acquisition / data logger switch unit 34970A of the brightness when driven by an AC voltage having a frequency of 30 Hz at which the relative transmittance is 23%.
The evaluation of the flicker level is defined as "○" when the flicker level is maintained at less than 3% from the time when the LED backlight is turned on and the application of the AC voltage is started until 60 minutes have passed. gone. When the flicker level reached 3% or more in 60 minutes, it was defined as "x" and evaluated.
The evaluation of the flicker level according to the above method was performed under the temperature condition of the liquid crystal cell at a temperature of 23 ° C.

<Evaluation result>
With respect to the liquid crystal display element using each of the liquid crystal alignment agents of Examples 1, 2, 4, 5 and Comparative Examples 1 to 4, 6 and 7, the afterimage erasing time carried out above and the flicker shift occurring immediately after the start of driving The evaluation results are shown in Tables 4 to 6.
In Tables 4 to 6, * 1 indicates the content (parts by mass) of each polymer with respect to 100 parts by mass of all the polymers.

As can be seen in Tables 4 to 6, in the liquid crystal display elements using the liquid crystal alignment agents of Examples 1, 2, 4, and 5, the accumulated charge is quickly relaxed and the flicker shift that occurs immediately after the start of driving is unlikely to occur. It turns out.

<Manufacturing of liquid crystal display element by optical orientation method>
After filtering the liquid crystal alignment agent with a filter having a pore size of 1.0 μm, an ITO film is formed on the back surface of the prepared substrate with electrodes as a facing substrate, and a glass substrate having a columnar spacer having a height of 4 μm is formed. Each was spin coated. Then, it was dried on a hot plate at 80 ° C. for 5 minutes and then fired at 230 ° C. for 30 minutes to obtain a polyimide film on each substrate as a coating film having a film thickness of 100 nm. The coating film surface was irradiated with ^{250 mJ / cm 2} of ultraviolet rays having a wavelength of 254 nm, which was linearly polarized with an extinction ratio of 26: 1 via a polarizing plate.

This substrate is immersed in an EL (ethyl lactate) solution at 25 ° C. for 5 minutes, then immersed in pure water at 25 ° C. for 1 minute, and then heated on a hot plate at 230 ° C. for 30 minutes to obtain a substrate with a liquid crystal alignment film. Got The above two substrates are made into a set, a sealant is printed on the substrate, and the other substrate is bonded so that the liquid crystal alignment film surfaces face each other and the orientation direction is 0 °, and then the sealant is applied. It was cured to prepare an empty cell. A negative liquid crystal display MLC-7026-100 (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 110 ° C. for 1 hour, left overnight, and then used for each evaluation.

<Evaluation of afterimage erasure time>
In the same manner as in the case of the liquid crystal display element by the rubbing method, the afterimage was evaluated using the optical system of the liquid crystal display element by the optical orientation method produced above.
<Evaluation of flicker level immediately after driving>
In the same manner as in the case of the liquid crystal display element by the rubbing method, the afterimage was evaluated using the optical system of the liquid crystal display element by the optical orientation method produced above.

<Evaluation result>
Table 7 shows the results of the evaluation of the afterimage erasing time and the evaluation of the flicker level immediately after driving with respect to the liquid crystal display element using the liquid crystal alignment agent obtained in Example 12 and Comparative Example 7. In Table 7, * 1 indicates the content (parts by mass) of each polymer with respect to 100 parts by mass of all the polymers.

As can be seen in Table 7, it can be seen that in the liquid crystal display element using the liquid crystal alignment agent of Example 12, the accumulated charge is quickly relaxed and the flicker shift that occurs immediately after the start of driving is unlikely to occur.

The liquid crystal aligning agent using the novel polymer of the present invention is widely used for a liquid crystal display element of a longitudinal electric field system such as a TN system or a VA system, particularly a horizontal electric field system such as an IPS system or an FFS system.
The entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2016-191765 filed on September 29, 2016 are cited here as the disclosure of the specification of the present invention. , Incorporate.

Claims (7)

At least one polymer selected from the group consisting of a polyimide precursor which is a polycondensate of a diamine having a structure represented by the following formula (1) and a tetracarboxylic acid dianhydride and a polyimide which is an imidized product thereof.

(In the formula (1), R ¹ and R ² are hydrogen atoms or monovalent organic groups. Any hydrogen atom in the benzene ring may be substituted with a monovalent organic group. Represents a binding site.) The polymer according to claim 1, wherein the diamine is represented by the following formula (2).

(In the formula (2), ^{the definitions of R 1} and R ² are the same as those in the above formula (1), and R ³ has a single bond independently or a structure represented by the following formula (3). , N represent an integer of 1-3. Any hydrogen atom of the benzene ring may be substituted with a monovalent organic group.)

(In formula (3), R ⁴ is a single bond, -O- _{, -COO-, -OCO-,-(CH 2} ) _l- , -O (CH ₂ ) _m O-, -CONH-, and- A divalent organic group selected from NHCO-represents (l and m represent integers from 1 to 5), * ₁ represents a site that binds to a benzene ring in formula (2), and * ₂ represents a site in formula (2). ) Represents the site that binds to the amino group in.) The polymer according to claim 1 or 2, wherein the polyimide precursor is represented by the following formula (4).

(In the formula (4), X ₁ is a tetravalent organic group derived from a tetracarboxylic acid derivative, Y ₁ is a divalent organic group derived from a diamine represented by the above formula (1), and R ₅ Is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.) The polymer according to claim 3, wherein in the formula (4), _{the structure of X 1} is at least one selected from the group consisting of the structures represented by the following (A-1) to (A-21).

A diamine represented by the following formula (2).

(In the formula (2), R ¹ and R ² are hydrogen atoms or monovalent organic groups, R ³ independently represent a single bond or the structure of the following formula (3), and n is 1. Represents an integer of ~ 3. Any hydrogen atom on the benzene ring may be substituted with a monovalent organic group.)

(In formula (3), R ⁴ is a single bond, -O- _{, -COO-, -OCO-,-(CH 2} ) _l- , -O (CH ₂ ) _m O-, -CONH-, and- A divalent organic group selected from NHCO-represents (l and m represent integers from 1 to 5), * ₁ represents a site that binds to a benzene ring in formula (2), and * ₂ represents a site in formula (2). ) Represents a site that binds to an amino group in.) The diamine according to claim 5, wherein the monovalent organic group in ^{R 1} and R ^{2 is a methyl group.} The diamine according to claim 5 or 6, wherein the diamine represented by the formula (2) is any of the diamines represented by the following formulas (2-1-1) to (2-1-12).

(In the above equations 2-1-6 and 2-1-7, n represents an integer from 1 to 5.)