JP2022109969A - Diamine and polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diamine that can give a liquid crystal alignment film that can keep low ion density in a liquid crystal display device and can quickly relax accumulated charge and, in particular, can reduce a misalignment between a rubbing direction and a liquid crystal alignment direction, which causes a problem in the in-plane switching system, and a polymer obtainable from the diamine.

SOLUTION: The present invention discloses a diamine having a structure represented by formula (1) [R is H or the like; R¹ is: H, an alkyl group or the like; W² is a single bond or a divalent organic group; Ar¹ is an aromatic ring; L¹ is a single bond, a carbonyl, a sulfonyl or a C1-20 alkylene].

SELECTED DRAWING: None

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention provides a novel diamine compound (also referred to herein simply as "diamine") useful as a raw material for polymers used in liquid crystal alignment films, and polymers obtained using the diamine (polyamic acid, polyamic acid esters, polyimides, etc.).

BACKGROUND ART Liquid crystal display elements have been widely used as display units of personal computers, mobile phones, television receivers, and the like. A lateral electric field method such as a field switching (Fringe Field Switching: hereinafter referred to as “FFS”) method is known. Generally, in the horizontal electric field method, in which electrodes are formed only on one side of the substrate and an electric field is applied parallel to the substrate to drive the liquid crystal, a vertical electric field is applied to the electrodes formed on the upper and lower substrates to drive the liquid crystal. Compared with the method, it is easy to obtain a liquid crystal display element capable of high-quality display, such as having wide viewing angle characteristics. As a technique for aligning liquid crystal in a certain direction, there is a method of forming a polymer film such as polyimide on a substrate and rubbing the surface with a cloth, which is called a rubbing treatment.

A conventional problem is the accumulation of charges due to the DC voltage component applied from the active matrix structure. Excessive accumulation of electric charges in the liquid crystal display element adversely affects display due to disturbance of liquid crystal alignment and generation of afterimages, thereby degrading the display quality of the liquid crystal display element. Alternatively, if the liquid crystal display element is driven in a state in which charges are accumulated, the liquid crystal molecules are not normally controlled immediately after the driving, resulting in flicker or the like.

In addition, properties required for the liquid crystal alignment film in order to improve the display quality of the liquid crystal display element include ion density and the like. If the ion density is excessively high, the voltage applied to the liquid crystal during the frame period will drop, resulting in a drop in brightness and a problem in normal gradation display. Moreover, even if the initial ion density is low, the ion density may become high after the high temperature accelerated test. The deterioration of long-term reliability and the generation of afterimages associated with such residual charges and ionic impurities cause deterioration of the display quality of liquid crystals.

Various proposals have been made for polyimide-based liquid crystal alignment films in order to meet the above demands. For example, in addition to polyamic acid and imide group-containing polyamic acid, a liquid crystal aligning agent containing a tertiary amine having a predetermined structure can be used as a liquid crystal alignment film with a short time until afterimages generated by DC voltage disappear ( For example, see Patent Document 1), and using a liquid crystal aligning agent containing a soluble polyimide using a predetermined diamine compound having a pyridine skeleton or the like as a raw material (see Patent Document 2, for example) has been proposed.

JP-A-9-316200 JP-A-10-104633

Rubbing treatment is widely used industrially as a method for aligning liquid crystals, but depending on the liquid crystal alignment film used, a phenomenon may occur in which the rubbing direction and the alignment direction of the liquid crystal do not match, that is, a so-called twist angle occurs. In other words, the horizontal electric field element exhibits black display when no voltage is applied, but due to this phenomenon, the brightness increases even when no voltage is applied, resulting in a decrease in display contrast. there were.

The present invention can suppress the ion density in the liquid crystal display element to a low level and can quickly relax the accumulated charges, and suppresses the deviation between the rubbing direction and the alignment direction of the liquid crystal, which is a problem especially in the horizontal electric field driving method. An object of the present invention is to provide a liquid crystal alignment film capable of Another object of the present invention is to provide a diamine, a polymer, and a liquid crystal alignment agent from which such a liquid crystal alignment film can be obtained. A further object of the present invention is to provide a liquid crystal display device having such a liquid crystal alignment film.

The present inventors have made intensive studies to solve the above problems, and as a result, various The inventors have found that the properties are improved at the same time, and completed the present invention. The present invention is based on such knowledge, and has the following gist.

1. A liquid crystal aligning agent containing a polymer obtained from a diamine having a structure represented by the following formula (1).

Ｒは水素原子又は一価の有機基を示し、Ｒ^１は水素原子又は炭素数１～５の直鎖又は分岐してもよい、アルキル基若しくはアリール基を示し、同じマレイミド環上に２つあるＲ^１は互いに同一でも、異なっていてもよく、２つあるＲ^１が互いに結合して炭素数３～６のアルキレンを形成してもよく、Ｗ^１は単結合又は２価の有機基を示し、Ｗ^２は２価の有機基を示し、Ａｒ^１は芳香族環を示し、Ｌ^１は単結合、カルボニル、スルホニル又は炭素数１～２０のアルキレンを示す。

R represents a hydrogen atom or a monovalent organic group, R ¹ represents a hydrogen atom or an alkyl group or aryl group having 1 to 5 carbon atoms, which may be linear or branched, and two are present on the same maleimide ring. R ¹ may be the same or different, two R ¹ may be bonded together to form an alkylene having 3 to 6 carbon atoms, and W ¹ represents a single bond or a divalent organic group. , W ² represents a divalent organic group, Ar ¹ represents an aromatic ring, and L ¹ represents a single bond, carbonyl, sulfonyl or alkylene having 1 to 20 carbon atoms.

2. 1. Ar ¹ is a 1,3-phenylene group or a 1,4-phenylene group; Liquid crystal aligning agent as described in .

3. 1. W ¹ is a single bond; or 2. Liquid crystal aligning agent as described in .

4. 1. The polymer is at least one selected from a polyimide precursor containing a structural unit represented by the following formula (3) and a polyimide which is an imidized product thereof. ~3. The liquid crystal aligning agent according to any one of.

Ｘ^１はテトラカルボン酸誘導体に由来する４価の有機基を示し、Ｙ^１は式（１）の構造を含むジアミンに由来する２価の有機基を示し、Ｒ^４は水素原子又は炭素数１～５のアルキル基を示す。

X ¹ represents a tetravalent organic group derived from a tetracarboxylic acid derivative, Y ¹ represents a divalent organic group derived from a diamine containing the structure of formula (1), and R ⁴ represents a hydrogen atom or 1 carbon atom. -5 alkyl groups.

5. 4. The structure of X1 is at least ^one selected from the following structures; Liquid crystal aligning agent as described in .

6. 1. The polymer is at least one selected from polyimide precursors and polyimides, which are imidized products thereof, further comprising a structural unit represented by the following formula (4). ~ 5. The liquid crystal aligning agent according to any one of.

Ｘ^２はテトラカルボン酸誘導体に由来する４価の有機基を示し、Ｙ^２は式（１）の構造を主鎖方向に含まないジアミンに由来する２価の有機基を示し、Ｒ^１４は、それぞれ独立に水素原子又は炭素数１～５のアルキル基を示し、Ｒ^１５はそれぞれ独立に水素原子又は炭素数１～４のアルキル基を示す。

X ² represents a tetravalent organic group derived from a tetracarboxylic acid derivative, Y ² represents a divalent organic group derived from a diamine that does not contain the structure of formula (1) in the main chain direction, and R ¹⁴ is Each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and each R ¹⁵ independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

7. 6. Y2 is represented by the following ^formula (11); Liquid crystal aligning agent as described in .

Ｒ^３２は単結合又は２価の有機基を示し、Ｒ^３３は－（ＣＨ_２）_ｒ－で表される構造を示し、ｒは２～１０の整数を示し、任意の－ＣＨ_２－はそれぞれ隣り合わない条件でエーテル、エステル、アミド、ウレア、カルバメート結合に置き換えられてもよく、Ｒ^３４は単結合又は２価の有機基を示し、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。

R ³² represents a single bond or a divalent organic group, R ³³ represents a structure represented by -(CH ₂ ) _r -, r represents an integer of 2 to 10, and any -CH ₂ - It may be replaced by an ether, ester, amide, urea, or carbamate bond under non-adjacent conditions, R ³⁴ represents a single bond or a divalent organic group, and any hydrogen atom on the benzene ring is a monovalent organic group. may be replaced with

8. 3. The structural unit represented by the formula (3) is 10 mol % or more of the total structural units of the polymer; ~7. The liquid crystal aligning agent according to any one of.

9. 1. ~8. The liquid crystal aligning film obtained from the liquid crystal aligning agent as described in any one of 1.

10. 9. A liquid crystal display device comprising the liquid crystal alignment film according to 1.

11. A polymer obtained from a diamine having a structure represented by the following formula (1).

Ｒは水素原子又は一価の有機基を示し、Ｒ^１は水素原子又は炭素数１～５の直鎖又は分岐してもよい、アルキル基若しく又はアリール基を示し、同じマレイミド環上に２つあるＲ^１は互いに同一でも、異なっていてもよく、２つあるＲ^１が互いに結合して炭素数３～６のアルキレンを形成してもよく、Ｗ^１は単結合又は２価の有機基を示し、Ｗ^２は２価の有機基を示し、Ａｒ^１は芳香族環を示し、Ｌ^１は単結合、カルボニル、スルホニル又は炭素数１～２０のアルキレンを示す。

R represents a hydrogen atom or a monovalent organic group, R ¹ represents a hydrogen atom or a linear or branched alkyl group or aryl group having 1 to 5 carbon atoms, and 2 on the same maleimide ring. Two R ^1s may be the same or different, two R ^1s may combine with each other to form an alkylene having 3 to 6 carbon atoms, and W ¹ is a single bond or a divalent organic group. , W ² represents a divalent organic group, Ar ¹ represents an aromatic ring, and L ¹ represents a single bond, carbonyl, sulfonyl or alkylene having 1 to 20 carbon atoms.

12. A diamine obtained from a diamine having a structure represented by the following formula (1).

Ｒは水素原子又は一価の有機基を示し、Ｒ^１は水素原子又は炭素数１～５の直鎖又は分岐してもよい、アルキル基若しく又はアリール基を示し、同じマレイミド環上に２つあるＲ^１は互いに同一でも、異なっていてもよく、２つあるＲ^１が互いに結合して炭素数３～６のアルキレンを形成してもよく、Ｗ^１は単結合又は２価の有機基を示し、Ｗ^２は２価の有機基を示し、Ａｒ^１は芳香族環を示し、Ｌ^１は単結合、カルボニル、スルホニル又は炭素数１～２０のアルキレンを示す。

R represents a hydrogen atom or a monovalent organic group, R ¹ represents a hydrogen atom or a linear or branched alkyl group or aryl group having 1 to 5 carbon atoms, and 2 on the same maleimide ring. Two R ^1s may be the same or different, two R ^1s may combine with each other to form an alkylene having 3 to 6 carbon atoms, and W ¹ is a single bond or a divalent organic group. , W ² represents a divalent organic group, Ar ¹ represents an aromatic ring, and L ¹ represents a single bond, carbonyl, sulfonyl or alkylene having 1 to 20 carbon atoms.

By using the liquid crystal aligning agent of the present invention, it is possible to keep the ion density in the liquid crystal display element low and to relax the accumulated electric charge quickly. A liquid crystal alignment film that can suppress the deviation of the alignment direction is obtained. The mechanism by which the present invention can solve the above problems is generally considered as follows. The structure of formula (1) contained in the polymer of the present invention has a nitrogen atom. As a result, for example, in the liquid crystal alignment film, it has the ability to capture ionic impurities, promote the transfer of charges, and facilitate the relaxation of accumulated charges.

Moreover, the said polymer and said liquid crystal aligning agent are obtained by using the diamine of this invention. Moreover, by providing the liquid crystal alignment film of the present invention, such a liquid crystal display device having excellent various characteristics can be obtained.

The liquid crystal aligning agent of the present invention contains a polymer (hereinafter also referred to as a specific polymer) obtained from a diamine having a structure represented by the above formula (1) (hereinafter also referred to as a specific structure).

<Diamine having a specific structure>
In the above formula (1), R represents a hydrogen atom or a monovalent organic group, R ¹ represents a hydrogen atom or a linear or branched alkyl group or aryl group having 1 to 5 carbon atoms, the same Two R ^{1's on the maleimide ring may be the same or different, two R 1 's} may be bonded together to form an alkylene having 3 to 6 carbon atoms, and W ¹ is a single bond or represents a divalent organic group, W ² represents a divalent organic group, Ar ¹ represents an aromatic ring, and L ¹ represents a single bond, carbonyl, sulfonyl or alkylene having 1 to 20 carbon atoms.

R is preferably a hydrogen atom or a linear alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group. Further, R may be a protective group that undergoes a desorption reaction by heat and is substituted with a hydrogen atom. It is a protective group that is released, more preferably a protective group that is released by heat at 100° C. or higher. Examples thereof include 1,1-dimethyl-2-chloroethoxycarbonyl group, 1,1-dimethyl-2-cyanoethoxycarbonyl group and tert-butoxycarbonyl group, preferably tert-butoxycarbonyl group.

R ¹ is preferably a hydrogen atom, a methyl group, an ethyl group, an iso-propyl group or a phenyl group, more preferably a hydrogen atom, a methyl group or a phenyl group. The alkylene having 3 to 6 carbon atoms formed by bonding two R ¹ to each other is preferably -(CH ₂ ) ₃ -, -(CH ₂ ) ₄ -, or -(CH ₂ ) ₅ -. and more preferably -(CH ₂ ) ₄ -.

W ¹ is a single bond, -O-, -COO-, -OCO-, -(CH ₂ ) _p -, -O(CH ₂ ) _q O-, -CONH- or -NHCO- An organic group is preferred, p represents a natural number of 1-10, and q represents a natural number of 1-10. Ar ¹ is preferably a 1,3-phenylene group or a 1,4-phenylene group.

L ¹ represents a single bond, carbonyl, sulfonyl or alkylene having 1 to 20 carbon atoms. The alkylene having 1 to 20 carbon atoms for L ¹ may be linear or branched, and is a linear alkylene represented by —(CH ₂ ) _n — (where n is 1 to 20). and 1-methylmethane-1,1-diyl, 1-ethylmethane-1,1-diyl, 1-propylmethane-1,1-diyl, 1-methylethane-1,2-diyl, 1-ethylethane-1, 2-diyl, 1-propylethane-1,2-diyl, 1-methylpropane-1,3-diyl, 1-ethylpropane-1,3-diyl, 1-propylpropane-1,3-diyl, 2- Methylpropane-1,3-diyl, 2-ethylpropane-1,3-diyl, 2-propylpropane-1,3-diyl, 1-methylbutane-1,4-diyl, 1-ethylbutane-1,4-diyl , 1-propylbutane-1,4-diyl, 2-methylbutane-1,4-diyl, 2-ethylbutane-1,4-diyl, 2-propylbutane-1,4-diyl, 1-methylpentane-1, 5-diyl, 1-ethylpentane-1,5-diyl, 1-propylpentane-1,5-diyl, 2-methylpentane-1,5-diyl, 2-ethylpentane-1,5-diyl, 2- propylpentane-1,5-diyl, 3-methylpentane-1,5-diyl, 3-ethylpentane-1,5-diyl, 3-propylpentane-1,5-diyl, 1-methylhexane-1, 6-diyl, 1-ethylhexane-1,6-diyl, 2-methylhexane-1,6-diyl, 2-ethylhexane-1,6-diyl, 3-methylhexane-1,6- Diyl, 3-ethylhexane-1,6-diyl, 1-methylheptane-1,7-diyl, 2-methylheptane-1,7-diyl, 3-methylheptane-1,7-diyl, 4-methyl Branched alkylenes such as heptane-1,7-diyl, 1-phenylmethane-1,1-diyl, 1-phenylethane-1,2-diyl and 1-phenylpropane-1,3-diyl are included. These linear or branched alkylenes may be interrupted 1 to 5 times by oxygen atoms or sulfur atoms provided that the oxygen atoms or sulfur atoms are not adjacent to each other.

The divalent organic group W ² is represented by the following formulas [W ² -1] to [W ² -152].

Among them, W ² -7, W ² -20, W ² -21, W ² -23, W ² -26, W ² -39, W ² -51 from the viewpoint of achieving both ion density suppression and liquid crystal alignment stability , ^W2-52 , ^W2-53 , ^W2-54 , ^W2-55 , ^W2-59 , ^W2-60 , ^W2-61 , ^W2-64 , ^W2-65 , ^W2-67 , W ² -68, W ² -69, W ² -70, W ² -71 are preferred.

<Method for producing specific diamine>
Although the method for synthesizing the diamine having a specific structure (which may be referred to herein as a "specific diamine") of the present invention is not particularly limited, for example, a nitromaleimide compound represented by the following formula (A1), A method of reacting with a diamino compound represented by the following formula (B1) to obtain an aminonitro compound represented by the following formula (C1) and reducing it can be mentioned.

Ｒ、Ｒ^１、Ｌ^１、Ａｒ^１、Ｗ^１及びＷ^２の定義は、上記式（１）と同様である。

The definitions of R, R ¹ , L ¹ , Ar ¹ , W ¹ and W ² are the same as in formula (1) above.

The amount of the compound represented by formula (B1) to be used is preferably 1 to 2 mol, preferably 1 to 1.2 mol, per 1 mol of the compound represented by formula (A1). More preferred. By using an excessive amount of the compound represented by formula (B1), the reaction can proceed smoothly and the production of by-products can be suppressed.

This reaction is preferably carried out in a solvent. Any solvent can be used without limitation as long as it 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.); hexane, heptane, petroleum ether, etc.); aromatic hydrocarbons (benzene, toluene, xylene, mesitylene, chlorobenzene, dichlorobenzene, nitrobenzene, tetralin, etc.); etc.); lower fatty acid esters (methyl acetate, ethyl acetate, butyl acetate, methyl propionate, etc.); nitriles (acetonitrile, propionitrile, butyronitrile, etc.);

These solvents can be appropriately selected in consideration of the easiness of reaction and the like, and can be used singly or in combination of two or more. If necessary, the solvent can be dried using a suitable dehydrating agent or drying agent and used as a non-aqueous solvent. The amount (reaction concentration) of the solvent used is not particularly limited, but it is 0.1 to 100 times the weight of the bismaleimide compound. It is preferably 0.5 to 30 times by mass, more preferably 1 to 10 times by mass. The reaction temperature is not particularly limited, but is in the range 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.

This reaction can be allowed to proceed in the presence of an inorganic base or an organic base, if necessary. The base used in the reaction includes inorganic bases such as sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, potassium phosphate, sodium carbonate, potassium carbonate, lithium carbonate, cesium carbonate; tert-butoxy; Bases such as sodium, tert-butoxypotassium, sodium hydride and potassium hydride; amines such as trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine, diisopropylethylamine, pyridine, quinoline and collidine can be used. Among them, triethylamine, pyridine, tert-butoxysodium, tert-butoxypotassium, sodium hydride, potassium hydride and the like are preferable. The amount of the base used is not particularly limited, but it is 0 to 100 times the weight of the bismaleimide compound. It is preferably 0 to 30 times by mass, more preferably 0 to 10 times by mass.

Conditions under which the compound represented by formula (C1) is reduced to produce the specific diamine represented by formula (1) are described below. As a method for reducing the compound represented by the above formula (C1), there is a reduction reaction performed in the coexistence of Fe, Sn, Zn or salts thereof and protons. The amount of Fe, Sn, Zn and salts thereof used is preferably 1 to 100 equivalents, particularly preferably 3 to 50 equivalents, relative to the compound represented by formula (1) above.

As the reaction solvent in this case, any solvent can be used as long as it does not interfere with the intended reaction under the reaction conditions. For example, water; alcohol solvents such as methyl alcohol, ethyl alcohol and tert-butyl alcohol; aprotic polar organic solvents such as dimethylformamide, dimethylsulfoxide, dimethylacetamide and N-methylpyrrolidone; diethyl ether, diisopropyl ether, tert-butyl ethers such as methyl ether, cyclopentyl methyl ether, tetrahydrofuran and dioxane; aliphatic hydrocarbons such as pentane, hexane, heptane and petroleum ether; aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene and tetralin, chloroform, dichloromethane, Halogen hydrocarbons such as carbon tetrachloride and dichloroethane; lower fatty acid esters such as methyl acetate, ethyl acetate, butyl acetate and methyl propionate; and nitriles such as acetonitrile, propionitrile and butyronitrile. These solvents can be appropriately selected in consideration of the easiness of reaction and the like, and can be used singly or in combination of two or more. In some cases, the above solvent can also be used as a water-free solvent by using a suitable dehydrating agent or drying agent. The amount (reaction concentration) of the solvent used is not particularly limited, but it is 0.1 to 100 times the mass of the compound represented by the above formula (C1). It is preferably 0.5 to 50 times by mass, more preferably 3 to 30 times by mass.

Furthermore, the reaction can be carried out under pressure in order to proceed the reaction more effectively. In this case, in order to avoid reduction of the benzene nucleus, the reaction is preferably carried out in a pressure range of about 20 atmospheres (kgf), more preferably up to 10 atmospheres. Furthermore, acids such as hydrochloric acid, sulfuric acid, formic acid, and acetic acid, and salts thereof may coexist. The amount of these to be used is not particularly limited, but is 0 to 10 times the mass of the compound represented by the above formula (C1). It is preferably 0 to 5 times by mass, more preferably 0 to 3 times by mass.

The reaction temperature is preferably selected from a temperature range from -100°C or higher to the boiling point of the reaction solvent used, more preferably -50 to 150°C, particularly preferably 0 to 100°C. . The reaction time is 0.1 to 1000 hours, more preferably 1 to 200 hours.

Methods for reducing the compound represented by the above formula (C1) include hydrogenation reactions using palladium-activated carbon, platinum-activated carbon, etc. as catalysts, reduction reactions using formic acid as a hydrogen source, and hydrazine as a hydrogen source. There are reactions such as Moreover, these reactions can also be implemented in combination. The catalyst used for the reduction reaction is preferably a commercially available metal supported on activated carbon, such as palladium-activated carbon, platinum-activated carbon, and rhodium-activated carbon. Also, the metal catalyst such as palladium hydroxide, platinum oxide, Raney nickel and the like may not necessarily be supported on activated carbon. Palladium-activated charcoal and platinum-activated charcoal, which are generally and widely used, are preferable because good results can be obtained. The amount of these catalysts to be used may be a so-called catalytic amount, preferably 20 mol % or less, particularly preferably 10 mol % or less, relative to the compound represented by the formula (C1).

As the reaction solvent in this case, any solvent can be used as long as it does not interfere with the intended reaction under the reaction conditions. For example, alcohol solvents such as methyl alcohol, ethyl alcohol and tert-butyl alcohol; aprotic polar organic solvents such as dimethylformamide, dimethylsulfoxide, dimethylacetamide and N-methylpyrrolidone; diethyl ether, isopropyl ether and tert-butyl methyl ether. Ethers such as , cyclopentyl methyl ether, tetrahydrofuran, dioxane; aliphatic hydrocarbons such as pentane, hexane, heptane, petroleum ether; aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, tetralin, chloroform, dichloromethane, tetrachloride halogenated hydrocarbons such as carbon and dichloroethane; lower fatty acid esters such as methyl acetate, ethyl acetate, butyl acetate and methyl propionate; and nitriles such as acetonitrile, propionitrile and butyronitrile. These solvents can be appropriately selected in consideration of the easiness of reaction and the like, and can be used singly or in combination of two or more. In some cases, the above solvent can also be used as a water-free solvent by using a suitable dehydrating agent or drying agent. The amount (reaction concentration) of the solvent used is not particularly limited, but it is 0.1 to 100 times the mass of the compound represented by the above formula (C1). It is preferably 0.5 to 50 times by mass, more preferably 3 to 30 times by mass. The reaction temperature is not particularly limited, but is in the range 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.

In order to proceed the reduction reaction more effectively, the reaction can be carried out in the presence of activated carbon. At this time, the amount of activated carbon used is not particularly limited, but it is preferably in the range of 1 to 30% by mass, more preferably 10 to 20% by mass, relative to the dinitro compound (C1). For similar reasons, the reaction may also be carried out under pressure. In this case, in order to avoid reduction of the benzene nucleus, the pressure range is up to 20 atmospheres. The reaction is preferably carried out in a range of up to 10 atmospheres. Among the reduction reactions exemplified above, the hydrogenation reaction is preferably used in consideration of the structure of the compound represented by the formula (C1) and the reactivity of the reduction reaction.

Further, as a method for obtaining the specific diamine of the present invention, a maleimide compound represented by the following formula (A1) and an aminonitro compound represented by the following formula (B2) are reacted to obtain the following formula (C2). A method of obtaining a dinitro compound represented by and reducing it can be exemplified.

The reaction conditions for the compound represented by formula (B2) and the compound represented by formula (A1) are the same as the reaction conditions for the compound represented by formula (B1) and the compound represented by formula (A1). comply. Further, the reaction conditions for reducing the dinitro compound represented by formula (C2) to obtain the diamine represented by formula (1) are as follows: ) conforms to the conditions for producing the specific diamine represented by

Further, as a method for obtaining the specific diamine of the present invention, a maleimide compound represented by the following formula (A2) and an aminonitro compound represented by the following formula (B2) are reacted to obtain the following formula (C3). A method of obtaining an aminonitro compound represented by and reducing it can be exemplified.

The reaction conditions for the compound represented by formula (B2) and the compound represented by formula (A2) are the same as the reaction conditions for the compound represented by formula (B1) and the compound represented by formula (A1). comply. Further, the reaction conditions for reducing the aminonitro compound represented by formula (C3) to obtain the diamine represented by formula (1) are as follows: It conforms to the conditions for producing the specific diamine represented by 1).

Further, as a method for obtaining the specific diamine of the present invention, a method of obtaining (1) by reacting a maleimide compound represented by the following formula (A2) with a diamino compound represented by the following formula (B1). can be mentioned.

式（Ｂ１）で表される化合物と式（Ａ２）で表される化合物との反応条件は、式（Ｂ１）で表される化合物と式（Ａ１）で表される化合物との反応条件に準ずる。

The reaction conditions for the compound represented by formula (B1) and the compound represented by formula (A2) conform to the reaction conditions for the compound represented by formula (B1) and the compound represented by formula (A1). .

When it is desired to introduce a monovalent organic group as R, a compound in which R is a hydrogen atom in the dinitro compound represented by the above formula (C2) may be reacted with a compound capable of reacting with amines. Examples of such compounds include acid halides, acid anhydrides, isocyanates, epoxies, oxetanes, aryl halides, and alkyl halides. can be used.

The method of introducing a monovalent organic group into the NH group is not particularly limited, but examples include a method of reacting an acid halide in the presence of a suitable base. Examples of acid halides include acetyl chloride, propionyl chloride, methyl chloroformate, ethyl chloroformate, n-propyl chloroformate, i-propyl chloroformate, n-butyl chloroformate, i-butyl chloroformate, t-chloroformate butyl, benzyl chloroformate, and 9-fluorenyl chloroformate. Examples of bases that can be used include those described above. The reaction solvent and reaction temperature conform to those described above.

A monovalent organic group may be introduced by reacting the NH group with an acid anhydride, and examples of the acid anhydride include acetic anhydride, propionic anhydride, dimethyl dicarbonate, diethyl dicarbonate, and ditertiary butyl dicarbonate. , dibenzyl dicarbonate and the like. A catalyst may be added to promote the reaction, and pyridine, collidine, N,N-dimethyl-4-aminopyridine and the like may be used. The catalyst amount is 0.0001 to 1 mol per 1 mol of the dinitro compound represented by the above formula (C2) in which R is a hydrogen atom. The reaction solvent and reaction temperature conform to those described above.

Monovalent organic groups may be introduced by reacting NH groups with isocyanates, and examples of isocyanates include methyl isocyanate, ethyl isocyanate, n-propyl isocyanate, and phenyl isocyanate. The reaction solvent and reaction temperature conform to those described above.

Epoxy compounds and oxetane compounds may be reacted with NH groups to introduce monovalent organic groups. Examples of epoxies and oxetanes include ethylene oxide, propylene oxide, 1,2-butylene oxide and trimethylene. oxide and the like. The reaction solvent and reaction temperature conform to those described above.

A monovalent organic group may be introduced by reacting an aryl halide to the NH group in the presence of a metal catalyst, a ligand and a base, and examples of the aryl halide include iodobenzene, bromobenzene, chlorobenzene, and the like. is mentioned. Examples of metal catalysts include palladium acetate, palladium chloride, palladium chloride-acetonitrile complex, palladium-activated carbon, bis(dibenzylideneacetone)palladium, tris(dibenzylideneacetone)dipalladium, bis(acetonitrile)dichloropalladium, bis(benzo nitrile)dichloropalladium, CuCl, CuBr, CuI, CuCN, and the like, but are not limited to these. Examples of ligands include triphenylphosphine, tri-o-tolylphosphine, diphenylmethylphosphine, phenyldimethylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane. , 1,4-bis(diphenylphosphino)butane, 1,1′-bis(diphenylphosphino)ferrocene, trimethylphosphite, triethylphosphite, triphenylphosphite, tri-tert-butylphosphine and the like. , but not limited to. Examples of bases that can be used include those described above. The reaction solvent and reaction temperature conform to those described above.

A monovalent organic group may be introduced by reacting the NH group with an alcohol in which the hydroxyl group of the alcohol is substituted with a leaving group such as OMs, OTf, or OTs in the presence of an appropriate base. , methanol, ethanol, 1-propanol, etc., and by reacting these alcohols with methanesulfonyl chloride, trifluoromethanesulfonyl chloride, p-toluenesulfonyl chloride, etc., elimination of OMs, OTf, OTs, etc. Group-substituted alcohols can be obtained. Examples of bases that can be used include those described above. The reaction solvent and reaction temperature conform to those described above.

An alkyl halide may be reacted with an NH group in the presence of an appropriate base to introduce a monovalent organic group. Examples of alkyl halides include methyl iodide, ethyl iodide, and n-propyl iodide. , methyl bromide, ethyl bromide, n-propyl bromide and the like. Examples of bases that can be used include metal alkoxides such as potassium-tert-butoxide, sodium-tert-butoxide, and the like, in addition to the aforementioned bases. The reaction conditions such as the reaction solvent, reaction temperature and reaction time conform to those described above.

The amount of the compound capable of reacting with the above amines is 1.0 to 3.0 per 1.0 molar equivalent of the dinitro compound represented by the above formula (C2) where R is a hydrogen atom. It can be about a molar equivalent. It is preferably in the range of 2.0 to 2.5 molar equivalents. In addition, the compounds capable of reacting with the above amines can be used alone or in combination.

When the diamine compound represented by the formula (1) has isomers derived from an asymmetric point, in the present application, each isomer and a mixture thereof are both the diamine represented by the formula (1). included. Further, when two R ¹ in the same maleimide ring of formula (1) are different from each other, the diamine compound represented by formula (1) differs in the substitution position of R ¹ . All mixtures thereof are also included in the diamine represented by formula (1).

[Manufacturing method of formula (A1)]
The method for synthesizing the compound of formula (A1) is not particularly limited, but examples include a method of reacting a commercially available nitroamine represented by formula (D1) below with a maleic anhydride derivative.

The amount of the maleic anhydride derivative to be used is preferably 1 to 1.5 mol, more preferably 1 to 1.2 mol, per 1 mol of the nitroamine compound represented by formula (D1). . By using an excessive amount of maleic anhydride, the reaction can proceed smoothly and by-products can be suppressed. This reaction is preferably carried out in a solvent. Preferred solvents and reaction conditions are the same as those for the production of compound (1) above.

[Manufacturing method of formula (A2)]
The method for synthesizing the compound of formula (A2) is not particularly limited. and a method of reacting a maleic anhydride derivative under the conditions described.

The amount of the maleic anhydride derivative used is preferably 0.01 to 1 mol, more preferably 0.1 to 1.0 mol, per 1 mol of the diamine compound represented by the formula (D2). More preferred. By using an excessive amount of the diamine (D2), the reaction can proceed smoothly and the production of by-products can be suppressed. This reaction is preferably carried out in a solvent. Preferred solvents and reaction conditions are the same as those for the production of compound (1) above.

A method of reducing a diamine represented by the following formula (A1) is also included.

The reaction conditions for reducing the nitro compound represented by formula (A1) to obtain the amine represented by formula (A2) are as follows: Among the reactions described in the conditions for producing the specific diamine, the reduction reaction performed in the coexistence of Fe, Sn, Zn or a salt thereof and protons is preferable from the viewpoint of suppressing the reduction of the double bond.

Further, the specific diamine of the present invention includes a maleimide compound represented by the following formula (A1) and ammonia, an alkylamine, a benzylamine, etc. represented by a commercially available amino compound represented by the following formula (E). to obtain a nitro compound represented by the following formula (F), and a commercially available nitrobenzyl chloride, nitrobenzoyl chloride, nitrobenzenesulfonyl chloride or nitrobenzene isocyanate represented by the following formula (G), 4- A method of obtaining the following formula (C2) by reacting it with fluoronitrobenzene, 4-iodonitrobenzene or the like and reducing it can be mentioned.

式（Ｅ）で表される化合物と式（Ａ１）で表される化合物との反応条件は、上記式（Ｂ１）で表される化合物と式（Ａ１）で表される化合物との反応条件に準ずる。

The reaction conditions for the compound represented by formula (E) and the compound represented by formula (A1) are the reaction conditions for the compound represented by formula (B1) and the compound represented by formula (A1). comply.

A compound represented by the above formula (G) in which Z is OH and L1 is carbonyl, and ^a compound represented by the above formula (F) are combined, if necessary, using a solvent inert to the reaction, and if necessary ^A compound of general formula (C2) in which L1 is carbonyl can be obtained by reacting with a condensing agent in the presence of a base. As for the amount of the reaction substrate, 0.5 to 2 equivalents of the compound represented by the general formula (F) can be used with respect to 1 equivalent of the compound represented by the formula (G).

The condensing agent is not particularly limited as long as it is commonly used in amide synthesis. 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride), CDI (carbonyldiimidazole), dimethylpropynylsulfonium bromide, propargyltriphenylphosphonium bromide, DEPC (diethyl cyanophosphate), etc., the above formula (G ) in which Z is OH and L ¹ is carbonyl.

When a solvent is used, the solvent to be used is not particularly limited as long as it does not hinder the progress of the reaction. Examples include aromatic hydrocarbons such as benzene, toluene and xylene, and aliphatic hydrocarbons such as hexane and heptane. , cyclohexane and other alicyclic hydrocarbons, chlorobenzene, dichlorobenzene and other aromatic halogenated hydrocarbons, dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,1,1-trichloroethane, trichlorethylene, tetrachlorethylene aliphatic halogenated hydrocarbons such as diethyl ether, 1,2-dimethoxyethane, tetrahydrofuran, 1,4-dioxane and other ethers, ethyl acetate, ethyl propionate and other esters, N,N-dimethylformamide, amides such as N,N-dimethylacetamide and N-methyl-2-pyrrolidone; amines such as triethylamine, tributylamine and N,N-dimethylaniline; pyridines such as pyridine and picoline; be done. These solvents may be used alone, or two or more of them may be mixed and used.

Addition of a base is not always necessary, but when a base is used, examples include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal carbonates such as sodium carbonate and potassium carbonate, sodium hydrogen carbonate and potassium hydrogen carbonate. alkali metal bicarbonates such as triethylamine, tributylamine, N,N-dimethylaniline, pyridine, 4-(dimethylamino)pyridine, imidazole, 1,8-diazabicyclo[5,4,0]-7-undecene, etc. 1 to 4 equivalents of an organic base or the like can be used with respect to the compound in which Z is OH and L ¹ is carbonyl in the above formula (G). The reaction temperature can be set at any temperature from -60°C to the reflux temperature of the reaction mixture, and the reaction time varies depending on the concentration of the reaction substrate and the reaction temperature, but is usually arbitrary in the range of 5 minutes to 100 hours. can be set to Generally, for example, 1 to 20 equivalents of the compound represented by the above formula (F) with respect to 1 equivalent of the compound in which Z is OH and L ¹ is carbonyl in the above formula (G), and 1 to 4 equivalents of Using a condensing agent such as WSC (1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride), CDI (carbonyldiimidazole), if necessary, 1 to 4 equivalents of potassium carbonate, triethylamine, pyridine, 4 -In the presence of a base such as (dimethylamino)pyridine, using no solvent or a solvent such as dichloromethane, chloroform, diethyl ether, tetrahydrofuran, 1,4-dioxane, etc., at a temperature range from 0°C to the reflux temperature of these solvents. , preferably for 10 minutes to 24 hours.

In addition, a compound of the above formula (G) in which Z is OH and L1 is carbonyl or sulfonyl is reacted with ^a chlorinating agent such as thionyl chloride, phosphorus pentachloride or oxalyl chloride by a known method described in the literature. method, a method of reacting an organic acid halide such as pivaloyl chloride or isobutyl chloroformate in the presence of a base if necessary, or a method of reacting with carbonyldiimidazole, sulfonyldiimidazole, or the like. ^a compound represented by the above formula (G) wherein Z is Cl and L1 is carbonyl or sulfonyl and the compound represented by the above formula (F), if necessary using a solvent inert to the reaction, ^A compound of general formula (C2) in which L1 is carbonyl or sulfonyl can also be synthesized by reacting in the presence of a base, if necessary. The amount of the reaction substrate is 0.5 to 2 equivalents of the compound represented by the above formula (F) with respect to 1 equivalent of the compound in which Z is Cl and L ¹ is carbonyl or sulfonyl in the above formula (G). be able to.

When a solvent is used, the solvent to be used is not particularly limited as long as it does not hinder the progress of the reaction. Examples include aromatic hydrocarbons such as benzene, toluene and xylene, and aliphatic hydrocarbons such as hexane and heptane. , cyclohexane and other alicyclic hydrocarbons, chlorobenzene, dichlorobenzene and other aromatic halogenated hydrocarbons, dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,1,1-trichloroethane, trichlorethylene, tetrachlorethylene aliphatic halogenated hydrocarbons such as diethyl ether, 1,2-dimethoxyethane, tetrahydrofuran, 1,4-dioxane and other ethers, ethyl acetate, ethyl propionate and other esters, N,N-dimethylformamide, amides such as N,N-dimethylacetamide and N-methyl-2-pyrrolidone; amines such as triethylamine, tributylamine and N,N-dimethylaniline; pyridines such as pyridine and picoline; . These solvents may be used alone, or two or more of them may be mixed and used.

Addition of a base is not always necessary, but when a base is used, examples include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal carbonates such as sodium carbonate and potassium carbonate, sodium hydrogen carbonate and potassium hydrogen carbonate. alkali metal bicarbonates such as triethylamine, tributylamine, N,N-dimethylaniline, pyridine, 4-(dimethylamino)pyridine, imidazole, 1,8-diazabicyclo[5,4,0]-7-undecene, etc. An organic base or the like can be used in an amount of 1 to 4 equivalents relative to the compound of formula (G) above wherein Z is Cl and L ¹ is carbonyl or sulfonyl. The reaction temperature can be set at any temperature from -60°C to the reflux temperature of the reaction mixture, and the reaction time varies depending on the concentration of the reaction substrate and the reaction temperature, but is usually arbitrary in the range of 5 minutes to 100 hours. can be set to Generally, for example, 1 to 10 equivalents of the compound represented by the above formula (F) per equivalent of the compound in which Z is Cl and L ¹ is carbonyl in the above formula (G) is added, if necessary, 1 To 2 equivalents of potassium carbonate, triethylamine, pyridine, 4-(dimethylamino)pyridine or the like in the presence of a base such as solvent-free or dichloromethane, chloroform, diethyl ether, tetrahydrofuran, 1,4-dioxane, ethyl acetate, acetonitrile, etc. It is preferable to carry out the reaction at a temperature in the range of 0° C. to the reflux temperature of the solvent for 10 minutes to 48 hours.

A nitro compound of formula (G) in which L ¹ and W ¹ are both single bonds, Z is F or Cl, and the NO ₂ group is at the 2- or 4-position relative to Z, is treated with an appropriate base. The dinitro compound represented by the formula (C2) can be obtained by reacting with the compound represented by the formula (F) in the presence. The base used is, 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 collidine; bases such as sodium hydride and potassium hydride; can be used.

Any solvent can be used as long as it does not react with the raw material. For example, aprotic polar organic solvents (N,N-dimethylformamide, dimethylsulfoxide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, etc.), ethers (Et ₂ O, i-Pr ₂ O, tert -Butyl methyl ether, cyclopentyl methyl ether, tetrahydrofuran, dioxane, etc.), aliphatic hydrocarbons (pentane, hexane, heptane, petroleum ether, etc.), aromatic hydrocarbons (benzene, toluene, xylene, mesitylene, chlorobenzene, dioxane, etc.) chlorobenzene, nitrobenzene, tetralin, etc.), halogenated hydrocarbons (chloroform, dichloromethane, carbon tetrachloride, dichloroethane, etc.), lower fatty acid esters (methyl acetate, ethyl acetate, butyl acetate, methyl propionate, etc.), nitriles (acetonitrile) , propionitrile, butyronitrile, etc.) can be used. These solvents can be appropriately selected in consideration of the easiness of reaction and the like. In this case, the above solvents may be used singly or in combination of two or more. In some cases, the solvent may be dehydrated and dried using a suitable dehydrating agent or drying agent. The reaction temperature can be selected arbitrarily in the range of -100°C to the boiling point of the solvent used, preferably in the range of -50 to 150°C. The reaction time can be arbitrarily selected in the range of 0.1 to 1000 hours, preferably 0.1 to 100 hours.

If Z is a Br or I atom, the NO ₂ group can be in the 2, 3 or 4 position with respect to X and includes a suitable metal catalyst and ligand to form a C—N cross in the presence of a base. A dinitro compound can be obtained by using a coupling reaction. Examples of metal catalysts include palladium acetate, palladium chloride, palladium chloride-acetonitrile complex, palladium-activated carbon, bis(dibenzylideneacetone)palladium, tris(dibenzylideneacetone)dipalladium, bis(acetonitrile)dichloropalladium, bis(benzo nitrile)dichloropalladium, CuCl, CuBr, CuI, CuCN, and the like, but are not limited to these. Examples of ligands include triphenylphosphine, tri-o-tolylphosphine, diphenylmethylphosphine, phenyldimethylphosphine, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane. , 1,4-bis(diphenylphosphino)butane, 1,1′-bis(diphenylphosphino)ferrocene, trimethylphosphite, triethylphosphite, triphenylphosphite, tri-tert-butylphosphine and the like. , but not limited to. Examples of bases that can be used include those described above. The reaction solvent and reaction temperature conform to those described above. The target product in each step obtained by each of the above reactions may be purified by distillation, recrystallization, or column chromatography using silica gel or the like, or the reaction solution may be directly subjected to the next step without purification. can. The reaction conditions for reducing the dinitro compound represented by formula (C2) to obtain the diamine represented by formula (1) are the same as those described above.

<Polymer>
The polymer of the present invention is obtained using the above diamine. Specific examples include polyamic acids, polyamic acid esters, polyimides, polyureas, and polyamides. From the viewpoint of use as liquid crystal aligning agents, polyimide precursors containing structural units represented by the following formula (3) and polyimide which is an imidized product thereof.

In the above formula (3), X ¹ represents a tetravalent organic group derived from a tetracarboxylic acid derivative, Y ¹ represents a divalent organic group derived from a diamine containing the structure of formula (1), and R ⁴ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R ⁴ is preferably a hydrogen atom, a methyl group, or an ethyl group from the viewpoint of ease of imidization by heating.

<Tetracarboxylic dianhydride>
X ¹ in the polyimide precursor is required properties such as solubility of the polymer in a solvent, applicability of a liquid crystal aligning agent, liquid crystal alignment when used as a liquid crystal alignment film, voltage holding ratio, accumulated charge, etc. may be selected as appropriate according to the degree of , one type may be used in the same polymer, or two or more types may be mixed. Specific examples of X ¹ include structures of formulas (X-1) to (X-46) described on pages 13 to 14 of WO 2015/119168. Preferred structures of X ¹ are shown below, but the present invention is not limited thereto.

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

<Polymer (other structural unit)>
The polyimide precursor containing the structural unit represented by the formula (3) is selected from the structural units represented by the following formula (4) and polyimides thereof as long as the effects of the present invention are not impaired. 1 type may be included.

In formula (4), X2 represents a tetravalent organic group derived from a tetracarboxylic ^acid derivative, and Y2 represents a ^divalent organic group derived from a diamine that does not contain the structure of formula (1) in the main chain direction. R ¹⁴ has the same definition as R ⁴ in formula (3) above, and each R ¹⁵ independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

Specific examples of X ² include the same structures as those exemplified for X ¹ in formula (3), including preferred examples. Moreover, Y2 in the polyimide precursor is a ^divalent organic group derived from a diamine that does not contain the structure of formula (1) in the main chain direction, and its structure is not particularly limited. In addition, Y ² depends on the degree of required characteristics such as the solubility of the polymer in a solvent, the applicability of the liquid crystal alignment agent, the alignment of the liquid crystal when used as a liquid crystal alignment film, the voltage holding ratio, the accumulated charge, etc. It may be selected as appropriate in the same polymer, and may be of one type or two or more types may be mixed in the same polymer.

Specific examples of Y ² include groups represented by the above formulas [W ² -1] to [W ² -152]. Further, the structure of formula (2) published on page 4 of International Publication 2015/119168, and the formulas (Y-1) to (Y-97) and (Y- 101) to (Y-118) structure; divalent organic group obtained by removing two amino groups from formula (2) published on page 6 of WO 2013/008906; 8 of WO 2015/122413 Divalent organic group with two amino groups removed from formula (1) published on page; structure of formula (3) published on page 8 of International Publication 2015/060360; Japanese Patent Publication 2012- 173514 page 8 of the formula (1) from which two amino groups are removed from the divalent organic group; and divalent organic groups excluding two. A preferable structure of Y ² includes the structure of the following formula (11).

In formula (11), R ³² is a single bond or a divalent organic group, preferably a single bond. R ³³ is a structure represented by —(CH ₂ ) _r —. r is an integer of 2-10, preferably 3-7. Any --CH ₂ -- may be replaced with an ether, ester, amide, urea, or carbamate bond under the condition that they are not adjacent to each other. ^R34 represents a single bond or a divalent organic group. Any hydrogen atom on the benzene ring may be replaced with a monovalent organic group, preferably a fluorine atom or a methyl group. Specific examples of the structure represented by formula (11) include, but are not limited to, the following structures.

When the polyimide precursor containing the structural unit represented by the formula (3) contains the structural unit represented by the formula (4) at the same time, the accumulated charges are quickly relaxed, and the rubbing direction and the alignment direction of the liquid crystal are misaligned. From the viewpoint of controlling, the structural unit represented by formula (3) is preferably 1 to 80 mol% with respect to the total of formula (3) and formula (4), more preferably 5 to 60 mol %, particularly preferably 10 to 40 mol %.

^A preferred structure of Y2 includes a structure having at least one selected from the group consisting of an amino group, an imino group, and a nitrogen-containing heterocyclic ring. Such a structure of Y ² has at least one structure selected from the group consisting of an amino group, an imino group, and a nitrogen-containing heterocyclic ring, or a thermally eliminable group is substituted on the nitrogen atom. The structure is not particularly limited as long as it has at least one structure selected from an amino group, an imino group and a nitrogen-containing heterocyclic ring. If I dare to give a specific example, at least one selected from the group consisting of an amino group, an imino group, and a nitrogen-containing heterocyclic ring represented by the following formulas (YD-1) to (YD-5) A divalent organic group having a structure can be mentioned.

In formula (YD-1), A ₁ represents a nitrogen atom-containing heterocyclic ring having 3 to 15 carbon atoms, and Z ₁ represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. show. In formula (YD-2), V ₁ represents a hydrocarbon group having 1 to 10 carbon atoms, A ₂ represents a monovalent organic group having 3 to 15 carbon atoms having a nitrogen atom-containing heterocyclic ring, or 1 carbon atom A disubstituted amino group substituted with ∼6 aliphatic groups is shown. In formula (YD-3), V ₂ represents a divalent organic group having 6 to 15 carbon atoms and 1 to 2 benzene rings, V ₃ represents alkylene or biphenylene having 2 to 5 carbon atoms, Z ₂ represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a benzene ring, or a thermally eliminable group; a represents an integer of 0 to 1; In formula (YD-4), A ₃ represents a nitrogen atom-containing heterocyclic ring having 3 to 15 carbon atoms. In formula (YD-5), A ₄ represents a nitrogen atom-containing heterocyclic ring having 3 to 15 carbon atoms, and V ₅ represents alkylene having 2 to 5 carbon atoms.

A ₁ , A ₂ , A ₃ , and A ₄ of formulas (YD-1), (YD-2), (YD-4), and (YD-5), nitrogen atom-containing heterocycles having 3 to 15 carbon atoms is not particularly limited as long as it has a known structure. Among them are pyrrolidine, pyrrole, imidazole, pyrazole, oxazole, thiazole, piperidine, piperazine, pyridine, pyrazine, indole, benzimidazole, quinoline, isoquinoline, piperazine, piperidine, indole, benzimidazole, imidazole, carbazole, and pyridine. more preferred. Further, the thermally releasable group may be any substituent group that does not detach at room temperature but is detached and replaced by a hydrogen atom when the alignment film is baked. An olenylmethoxycarbonyl group is mentioned.

Specific examples of such Y ² include divalent organic groups having a nitrogen atom represented by the following formulas (YD-6) to (YD-52), which can suppress charge accumulation due to AC drive. Therefore, formulas (YD-14) to (YD-21) are more preferred, and (YD-14) and (YD-18) are particularly preferred.

式（ＹＤ－１４）及び（ＹＤ－２１）中、ｊは０～３の整数を示す。

In formulas (YD-14) and (YD-21), j represents an integer of 0-3.

式（ＹＤ－２４）、（ＹＤ－２５）、（ＹＤ－２８）及び（ＹＤ－２９）中、ｊは０～３の整数を示す。

In formulas (YD-24), (YD-25), (YD-28) and (YD-29), j represents an integer of 0-3.

式（ＹＤ－５０）中、ｍ、ｎはそれぞれ１～１１の整数を示し、ｍ＋ｎは２～１２の整数を示す。

In formula (YD-50), m and n each represent an integer of 1-11, and m+n represents an integer of 2-12.

<Method for producing polyamic acid>
Polyamic acid, which is a polyimide precursor used in the present invention, can be synthesized by the method shown below. Specifically, a tetracarboxylic dianhydride and a diamine are reacted in the presence of an organic solvent at −20 to 150° C., preferably 0 to 70° C., for 30 minutes to 24 hours, preferably 1 to 12 hours. can be synthesized by The organic solvent used in the above reaction is preferably N,N-dimethylformamide, N-methyl-2-pyrrolidone, γ-butyrolactone, or the like from the viewpoint of the solubility of the monomer and polymer. may be used. The concentration of the polymer is preferably 1 to 30% by mass, more preferably 5 to 20% by mass, from the viewpoints that precipitation of the polymer hardly occurs and that a high molecular weight product is easily obtained.

The polyamic acid obtained as described above can be collected by precipitating a polymer by injecting the reaction solution into a poor solvent while stirring well. Further, a purified polyamic acid powder can be obtained by performing precipitation several times, washing with a poor solvent, and drying at room temperature or by heating. The poor solvent is not particularly limited, but includes water, methanol, ethanol, 2-propanol, hexane, butyl cellosolve, acetone, toluene and the like, preferably water, methanol, ethanol, 2-propanol and the like.

<Method for producing polyimide>
The polyimide used in the present invention can be produced by imidating the polyamic acid. When producing a polyimide from a polyamic acid, chemical imidization by adding a catalyst to the solution of the polyamic acid obtained by the reaction of the diamine component and the tetracarboxylic dianhydride is convenient. Chemical imidization is preferable because the imidization reaction proceeds at a relatively low temperature and the molecular weight of the polymer is less likely to decrease during the imidization process. Chemical imidization can be carried out by stirring a polymer to be imidized in an organic solvent in the presence of a basic catalyst and an acid anhydride. As the organic solvent, the solvent used in the polymerization reaction described above can be used. Basic catalysts include pyridine, triethylamine, trimethylamine, tributylamine, trioctylamine and the like. Among them, pyridine is preferable because it has an appropriate basicity for advancing the reaction. Examples of the acid anhydride include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride. Among them, acetic anhydride is preferred because it facilitates purification after the reaction is completed.

The imidization reaction temperature is -20 to 140°C, preferably 0 to 100°C, and the reaction time is 1 to 100 hours. The amount of the basic catalyst is 0.5 to 30 times the moles of the polyamic acid groups, preferably 2 to 20 times the moles, and the amount of the acid anhydride is 1 to 50 times the moles of the polyamic acid groups, preferably 3 to 30 times the moles. Mole. The imidization rate of the resulting polymer can be controlled by adjusting the catalyst amount, temperature and reaction time. Since the added catalyst and the like remain in the solution after the imidization reaction of the polyamic acid, the obtained imidized polymer is recovered by the means described below, redissolved in an organic solvent, and the present invention It is preferable to set it as the liquid crystal aligning agent of this.

The polyimide solution obtained as described above is poured into a poor solvent while stirring well to precipitate a polymer. Precipitation is carried out several times, washed with a poor solvent, and dried at room temperature or by heating to obtain a purified polymer powder. The poor solvent is not particularly limited, but includes methanol, 2-propanol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene and the like, and methanol, ethanol, 2-propanol, Acetone and the like are preferred.

<Polyimide Precursor - Production of Polyamic Acid Ester>
A polyamic acid ester, which is a polyimide precursor used in the present invention, can be produced by the following production methods (1), (2), or (3).

(1) Production from polyamic acid A polyamic acid ester can be produced by esterifying the polyamic acid produced as described above. Specifically, a polyamic acid and an esterifying agent are reacted in the presence of an organic solvent at -20°C to 150°C, preferably 0°C to 50°C, for 30 minutes to 24 hours, preferably 1 to 4 hours. can be manufactured. As the esterifying agent, those that can be easily removed by purification are preferable, and include N,N-dimethylformamide dimethyl acetal, N,N-dimethylformamide diethyl acetal, N,N-dimethylformamide dipropyl acetal, and N,N-dimethylformamide. Dineopentyl butyl acetal, N,N-dimethylformamide di-t-butyl acetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p -tolyltriazene, 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride and the like. The amount of the esterifying agent to be added is preferably 2 to 6 molar equivalents per 1 mol of repeating units of the polyamic acid.

Examples of organic solvents include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone or γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide or 1,3-dimethyl- Imidazolidinones are mentioned. Further, when the polyimide precursor has high solvent solubility, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or formulas [D-1] to [D-3] described later. A solvent represented by can be used.

These solvents may be used alone or in combination. Furthermore, even a solvent that does not dissolve the polyimide precursor may be mixed with the solvent and used as long as the resulting polyimide precursor does not precipitate. Moreover, water in the solvent inhibits the polymerization reaction and further causes hydrolysis of the formed polyimide precursor, so it is preferable to use a dehydrated and dried solvent. The solvent used in the above reaction is preferably N,N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone in view of the solubility of the polymer, and these may be used singly or in combination of two or more. good. The concentration at the time of production is preferably 1 to 30% by mass, more preferably 5 to 20% by mass, from the viewpoints that precipitation of the polymer is less likely to occur and a high molecular weight product can be easily obtained.

(2) Production by reaction of tetracarboxylic acid diester dichloride and diamine Polyamic acid ester can be produced from tetracarboxylic acid diester dichloride and diamine. Specifically, a tetracarboxylic acid diester dichloride and a diamine are mixed in the presence of a base and an organic solvent at -20°C to 150°C, preferably 0°C to 50°C, for 30 minutes to 24 hours, preferably 1 to 4 hours. It can be produced by reacting. Pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used as the base, but pyridine is preferred because the reaction proceeds moderately. The amount of the base to be added is preferably 2 to 4 times the molar amount of the tetracarboxylic acid diester dichloride because it is an amount that can be easily removed and a high molecular weight product can be easily obtained.

The solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone in terms of solubility of the monomer and polymer, and these may be used alone or in combination of two or more. The polymer concentration during production is preferably 1 to 30% by mass, more preferably 5 to 20% by mass, from the viewpoints that precipitation of the polymer is less likely to occur and a high molecular weight product can be easily obtained. Moreover, in order to prevent hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used in the production of the polyamic acid ester is preferably dehydrated as much as possible, and is preferably kept in a nitrogen atmosphere to prevent contamination with outside air.

(3) Production from tetracarboxylic acid diester and diamine Polyamic acid ester can be produced by polycondensation of tetracarboxylic acid diester and diamine. Specifically, a tetracarboxylic acid diester and a diamine are reacted in the presence of a condensing agent, a base, and an organic solvent at 0 to 150°C, preferably 0 to 100°C, for 30 minutes to 24 hours, preferably 3 to 15 hours. It can be manufactured by The condensing agent includes triphenylphosphite, dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N,N'-carbonyldiimidazole, dimethoxy-1,3,5-triazide Nylmethylmorpholinium, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium Tetrafluoroborate, O-(benzotriazol-1-yl)-N,N , N′,N′-tetramethyluronium hexafluorophosphate, diphenyl (2,3-dihydro-2-thioxo-3-benzoxazolyl)phosphonate and the like can be used. The amount of the condensing agent to be added is preferably 2 to 3 times the molar amount of the tetracarboxylic acid diester.

Tertiary amines such as pyridine and triethylamine can be used as the base. The amount of the base to be added is preferably 2 to 4 times the molar amount of the diamine component because it is an amount that can be easily removed and a high molecular weight product can be easily obtained. Moreover, in the above reaction, the reaction proceeds efficiently by adding a Lewis acid as an additive. Preferred Lewis acids are lithium halides such as lithium chloride and lithium bromide. The amount of the Lewis acid to be added is preferably 0 to 1.0 times the molar amount of the diamine component. Among the above three methods for producing a polyamic acid ester, the above method (1) or (2) is particularly preferable because a high-molecular-weight polyamic acid ester can be obtained.

The solution of the polyamic acid ester obtained as described above is poured into a poor solvent while stirring well to precipitate the polymer. Precipitation is carried out several times, washed with a poor solvent, and dried at room temperature or by heating to obtain a purified polyamic acid ester powder. Poor solvents include, but are not limited to, water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.

In order to produce the polymer of the present invention, the diamine represented by the formula (1) may be used as the diamine in the above production method. The molecular weight of the polyimide precursor or polyimide, which is the polymer contained in the liquid crystal aligning agent of the present invention, is such that when a liquid crystal aligning film is obtained from the liquid crystal aligning agent containing the polymer, the coating film (liquid crystal aligning film) is Considering the strength, workability during coating film formation, and uniformity of the coating film, the weight average molecular weight measured by GPC (Gel Permeation Chromatography) method is preferably 2,000 to 500,000. 000 to 300,000, more preferably 10,000 to 100,000.

<Liquid crystal aligning agent>
The liquid crystal aligning agent of the present invention contains a polymer (specific polymer) obtained from a diamine having a structure represented by Formula (1). Moreover, two or more kinds of specific polymers having different structures may be included as long as the effects described in the present invention are exhibited. Moreover, in addition to the specific polymer, other polymers, that is, polymers having no divalent group represented by formula (1) may be included. Other polymer types include polyamic acid, polyimide, polyamic acid ester, polyester, polyamide, polyurea, polyorganosiloxane, cellulose derivative, polyacetal, polystyrene or its derivative, poly(styrene-phenylmaleimide) derivative, poly(meth) ) acrylates and the like. When the liquid crystal aligning agent of the present invention contains other polymer, the ratio of the specific polymer to the total polymer component is preferably 5% by mass or more, and an example thereof is 5 to 95% by mass.

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

The organic solvent contained in the liquid crystal aligning agent is not particularly limited as long as it uniformly dissolves the polymer component. Specific examples include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethylsulfoxide, γ-butyrolactone, 1,3-dimethyl - imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone and the like. Among them, it is preferable to use N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ-butyrolactone.

In addition, the organic solvent contained in the liquid crystal aligning agent is to use a mixed solvent in which a solvent that improves the coatability and the surface smoothness of the coating film when applying the liquid crystal aligning agent in addition to the above solvents is used. is common, and such a mixed solvent is preferably used also in the liquid crystal aligning agent of the present invention. Specific examples of the organic solvent used in combination are listed below, but are 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-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 1,2- ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentane diol, 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-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 2-pentanone, 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 , methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, lactic acid methyl ester, lactic acid ethyl ester, Examples include n-propyl lactate, n-butyl lactate, isoamyl lactate, solvents represented by the following formulas [D-1] to [D-3], and the like.

式［Ｄ－１］中、Ｄ^１は炭素数１～３のアルキル基を示し、式［Ｄ－２］中、Ｄ^２は炭素数１～３のアルキル基を示し、式［Ｄ－３］中、Ｄ^３は炭素数１～４のアルキル基を示す。

In formula [D-1], D ¹ represents an alkyl group having 1 to 3 carbon atoms, in formula [D-2], D ² represents an alkyl group having 1 to 3 carbon atoms, and formula [D-3] Among them, D3 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 Preference is given to using dipropylene glycol dimethyl ether. The type and content of such a solvent are appropriately selected according to the liquid crystal aligning agent coating device, coating conditions, coating environment, and the like.

The liquid crystal aligning agent of the present invention may additionally contain components other than the polymer component and the organic solvent as long as the effects of the present invention are not impaired. 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 liquid crystal alignment. Examples include dielectrics and conductive substances for adjusting the dielectric constant and electrical resistance of the film. Specific examples of these additional components are as disclosed in various known documents related to liquid crystal aligning agents. One example is WO 2015/060357, page 53 [0105] to page 55. [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. 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 to obtain a film that is subjected to a rubbing treatment method or a photo-alignment treatment method. and a method of performing orientation treatment. The substrate to which the liquid crystal aligning 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 also be used. In this case, 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 simplification of the process. In addition, in a reflective liquid crystal display element, if only one substrate is used, an opaque material such as a silicon wafer can be used, and in this case, a light-reflecting material such as aluminum can be used for the electrodes.

The method of applying the liquid crystal aligning agent is not particularly limited, but industrially, screen printing, offset printing, flexographic printing, ink jet method and the like are common. Other coating methods include a dipping 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 the liquid crystal aligning agent is applied onto the substrate, the solvent is evaporated by heating means such as a hot plate, a thermal circulation oven, an IR (infrared) oven, and baked. The drying after applying a liquid crystal aligning agent and a baking process can select arbitrary temperature and time. Usually, in order to sufficiently remove the contained solvent, the conditions include calcination at 50 to 120° C. for 1 to 10 minutes, followed by calcination at 150 to 300° C. for 5 to 120 minutes. The thickness of the liquid crystal alignment film after baking is not particularly limited, but if it is too thin, the reliability of the liquid crystal display element may be lowered. The liquid crystal alignment film of the present invention is suitable as a liquid crystal alignment film for horizontal electric field liquid crystal display elements such as IPS system and FFS system, and is particularly useful as a liquid crystal alignment film for FFS system liquid crystal display elements.

<Liquid crystal display element>
The liquid crystal display element of the present invention can be obtained by obtaining a substrate with a liquid crystal alignment film obtained from the above liquid crystal alignment agent, producing a liquid crystal cell by a known method, and using the liquid crystal cell. As an example of a method of manufacturing a liquid crystal cell, a liquid crystal display element having a passive matrix structure will be described as an example. A liquid crystal display element having an active matrix structure in which a switching element such as a TFT (Thin Film Transistor) or the like is provided in each pixel portion constituting an image display may be used. Specifically, transparent glass substrates are prepared, a common electrode is provided on one substrate, and a segment electrode is provided on the other substrate. These electrodes can be ITO electrodes, for example, 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 electrodes and the segment electrodes. The insulating film can be, for example, a film made of SiO ₂ —TiO ₂ formed by a sol-gel method. Next, a liquid crystal alignment film is formed on each substrate under the above conditions.

Next, for example, a UV-curing sealing material is placed at a predetermined location on one of the two substrates on which the liquid crystal alignment film is formed, and liquid crystals are placed at several predetermined locations on the surface of the liquid crystal alignment film. After that, the other substrate is attached and pressed so that the liquid crystal alignment film faces each other, and the liquid crystal is spread to the front surface of the liquid crystal alignment film. get a cell Alternatively, as a step after the liquid crystal alignment film is formed on the substrates, when a sealing material is placed at a predetermined location on one of the substrates, an opening that can be filled with the liquid crystal from the outside is provided, and the liquid crystal is supplied. After the substrates are bonded together without disposing, a liquid crystal material is injected into the liquid crystal cell through an opening provided in the sealing material, and then the opening is sealed with an adhesive to obtain a liquid crystal cell. The injection of the liquid crystal material may be performed by a vacuum injection method or by a method utilizing capillary action in the air.

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 projection is provided on one of the substrates, spacers are scattered on one of the substrates, or a sealing material is used. It is preferable to take measures such as mixing a spacer into the . Examples of the liquid crystal material include nematic liquid crystals and smectic liquid crystals. Among them, nematic liquid crystals are preferable, and either positive liquid crystal materials or negative liquid crystal materials may be used. Next, a 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. In addition, the liquid crystal aligning film and liquid crystal display element of this invention are not limited to said description, as long as the liquid crystal aligning agent of this invention is used, They may be created by another well-known method. The process of obtaining a liquid crystal display element from a liquid crystal aligning agent is disclosed in, for example, Japanese Patent Application Laid-Open No. 2015-135393, page 17 [0074] to page 19 [0081], and many other documents.

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these.
The abbreviations of the compounds used in the Examples and Comparative Examples and the method of characterization are as follows.
NMP: N-methyl-2-pyrrolidone BCS: butyl cellosolve GBL: γ-butyl lactone
BCS: butyl cellosolve DA-1-1: compound represented by the following formula DA-1-1 DA-2: compound represented by the following formula DA-2 DA-3: compound CA represented by the following formula DA-3 -1: compound represented by the following formula CA-1 CA-2: compound represented by the following formula CA-2

[Example 1]
Synthesis of (DA-1-1)

After adding 15.00 g (68.8 mmol) of N-(4-nitrophenyl)maleimide and 300 g of terorahydrofuran (hereinafter referred to as THF) into the flask, the mixture was ice-cooled. Into the mixture was added 10.84 g (72.2 mmol) of 4-(2-methylaminoethyl)aniline. Then, after gradually returning to room temperature, the mixture was stirred at room temperature for 3 hours. After confirming the completion of the reaction, THF was distilled off under reduced pressure. n-Hexane was added to the resulting residue and stirred. The resulting precipitate was filtered. The obtained crystals were dried at 50° C. to obtain 21.7 g of the target nitro intermediate (DA-1-1-1) (yield 84%).
1H-NMR (D6-DMSO, δ ppm): 8.36 (d, 2H), 7.61 (d, 2H), 6.88 (d, 2H), 6.49 (d, 2H), 4.84 (brs, 2H), 4.20-4.25 (m, 1H), 2.91-3.00 (m, 1H), 2.65-2.83 (m, 3H), 2.54-2 .61 (m, 2H), 2.37 (s, 3H)

10 g (27.1 mmol) of (DA1-1-1), 1 g of 5% Pd—C (STD type, wet product, manufactured by NE Chemcat Co., Ltd.) and 250 g of THF were placed in a nitrogen-purged flask, The inside of the flask was replaced with hydrogen. The reaction mixture was stirred at room temperature for 2 days under normal hydrogen pressure. After confirming the completion of the reaction, Pd—C was removed from the reaction mixture by filtration, and the filtrate was evaporated under reduced pressure. 50 g of diisopropyl alcohol (hereinafter, IPA) was added to the resulting residue and stirred. The obtained crystals were filtered and dried at 50° C. to obtain 7.9 g of the desired product (DA-1-1) as pale red crystals (yield 86%).
1H-NMR (D6-DMSO, δ ppm): 6.87 (d, 2H), 6.81 (d, 2H), 6.58 (d, 2H), 6.48 (d, 2H), 5.30 (brs, 2H), 4.83 (brs, 2H), 4.06-4.12 (m, 1H), 2.81-2.90 (m, 1H), 2.60-2.73 (m , 3H), 2.52-2.59 (m, 2H), 2.31 (s, 3H)

[Example 2]
Synthesis of (DA-1-2)

After adding 10.00 g (45.8 mmol) of N-(4-nitrophenyl)maleimide and 200 g of THF into the flask, the mixture was ice-cooled. 22.4 g (50.0 mmol) of 7%-methylamine-THF solution was added dropwise into the mixture. After that, the mixture was stirred for 3 hours under ice-cooling. After confirming the completion of the reaction, THF was distilled off under reduced pressure to quantitatively obtain the desired intermediate (DA-1-2-1) as white crystals.
1H-NMR (D6-DMSO, δ ppm): 8.38 (d, 2H), 7.62 (d, 2H), 3.81-3.87 (m, 1H), 3.03-3.14 ( m, 1H), 2.56-2.66 (m, 1H), 2.66 (brs, 1H), 2.42 (s, 3H)

After adding 11.4 g (45.7 mmol) of (DA-1-2-1), 200 g of THF and 5.10 g (50.4 mmol) of triethylamine into the flask, the mixture was ice-cooled. 8.08 g (43.5 mol) of 4-nitrobenzoyl chloride was added to the mixture and stirred for 3 hours under ice-cooling. After confirming that the reaction was completed, the precipitate was filtered. The resulting filtrate was distilled off under reduced pressure to obtain crude (DA-1-2-2). 600 g of IPA and 100 g of pure water were added to the resulting crude product and stirred. The obtained crystals were filtered and dried under reduced pressure at 45° C. to obtain the objective dinitro compound (DA-1-2-2) as white crystals.
1H-NMR (D6-DMSO, δ ppm): 8.32-8.44 (m, 4H), 7.73-7.81 (m, 2H), 7.58-7.68 (m, 2H), 4.93-5.13 (m, 1H), 3.00-3.37 (m+s, 2H+3H)

In a nitrogen-purged flask, 2 g (5.02 mmol) of (DA-1-2-2), 0.5 g of 5% Pd-C (STD type, wet product, manufactured by NE Chemcat Co., Ltd.) and N, After adding 20 g of N-dimethylformamide (hereinafter referred to as DMF), the inside of the flask was replaced with hydrogen. The reaction mixture was stirred at room temperature for 2 days under normal hydrogen pressure. After confirming the completion of the reaction, Pd—C was removed from the reaction mixture by filtration, and the filtrate was evaporated under reduced pressure. 50 g of methyl alcohol and 2 g of activated carbon (manufactured by Nippon EnviroChemicals Co., Ltd., trade name: Tokusei Shirasagi) were added to the obtained residue and filtered. The filtrate was distilled off under reduced pressure, and 50 g of IPA was added to the obtained residue for crystallization. After filtering the obtained crystals, they were dried under reduced pressure at 45° C. to obtain 1.2 g of the desired (DA-1-2) as white crystals (yield 71%).
1H-NMR (D6-DMSO, δ ppm): 7.19-7.25 (m, 2H), 6.83-6.88 (m, 2H), 6.53-6.62 (m, 4H), 5.93 (brs, 2H), 5.31 (brs, 2H), 4.50-4.90 (m, 1H), 2.98-3.20 (m, 3H), 2.71-2. 96 (m, 2H)

[Example 3]
Synthesis of (DA-1-3)

After adding 15.66 g (71.8 mmol) of N-(4-nitrophenyl)maleimide and 300 g of THF into the flask, the mixture was ice-cooled. Into the mixture, 35.0 g (78.9 mmol) of 7%-methylamine-THF solution was added dropwise. After that, the mixture was stirred for 3 hours under ice-cooling. After confirming the completion of the reaction, THF was distilled off under reduced pressure to quantitatively obtain the desired intermediate (DA-1-2-1) as white crystals.

After adding 17.8 g (71.4 mmol) of (DA-1-2-1) obtained above, 300 g of THF and 7.99 g (79.0 mmol) of triethylamine into the flask, the mixture was ice-cooled. 15.1 g (68.1 mol) of 4-nitrobenzenesulfonyl chloride was added to the mixture and stirred at 40° C. for 14 hours. After confirming that the reaction was completed, the precipitate was filtered. The resulting filtrate was distilled off under reduced pressure to obtain crude (DA-1-3-1). 200 g of methanol and 30 g of pure water were added to the resulting crude product, and the mixture was stirred at 50° C. for 1 hour. After cooling, the crystals obtained were filtered. The obtained crystals were added to 250 g of methanol and stirred at 50° C. for 1 hour. This operation was repeated twice. The resulting crystals were dried under reduced pressure at 45° C. to obtain 19.5 g of the objective dinitro compound (DA-1-3-1) as purple crystals.
1H-NMR (D6-DMSO, δppm): 8.43-8.8.48 (m, 2H), 8.34-8.41 (m, 2H), 8.12-8.17 (m, 2H ), 7.57-7.63 (m, 2H), 5.48-5.55 (m, 1H), 3.04-3.14 (m, 1H), 2.91-3.02 (m , 1H), 2.86(s, 3H)

In a nitrogen-substituted flask, 1 g (2.30 mmol) of (DA-1-3-1), 0.5 g of 5% Pd-C (STD type, wet product, manufactured by NE Chemcat Co., Ltd.) and N, After adding 10 g of N-dimethylformamide (hereinafter referred to as DMF) and 5 g of methanol, the inside of the flask was replaced with hydrogen. The reaction mixture was stirred at room temperature for 5 days under normal hydrogen pressure. After confirming the completion of the reaction, Pd—C was removed from the reaction mixture by filtration, and the filtrate was evaporated under reduced pressure. 20 g of THF and 1 g of activated carbon (manufactured by Nippon EnviroChemicals Co., Ltd., trade name: Tokusei Shirasagi) were added to the resulting residue, followed by filtration. The filtrate was distilled off under reduced pressure, and 10 g of ethyl alcohol was added to the resulting residue for crystallization. After filtering the obtained crystals, they were dried under reduced pressure at 45° C. to obtain 0.56 g of the desired (DA-1-3) as yellow crystals (yield 65%).
1H-NMR (D6-DMSO, δ ppm): 7.42-7.48 (m, 2H), 6.80-6.86 (m, 2H), 6.61-6.68 (m, 2H), 6.54-6.60 (m, 2H), 6.10 (brs, 2H), 5.32 (brs, 2H), 5.14-5.20 (m, 1H), 2.66-2. 79 (m, 1H), 2.60 (s, 3H), 2.51-2.59 (m, 1H)

[Viscosity measurement]
In the following examples and comparative examples, the viscosity of the polyamic acid solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.), a sample amount of 1.1 mL, a cone rotor TE-1 (1 ° 34', R24).

[Example 4]
Synthesis of polyamic acid solution (PAA-1) After adding 2.36 g (7 mmol) of (DA-1-1) to a 50 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, add 25.0 g of NMP, The solution was dissolved by stirring while blowing nitrogen. While stirring this diamine solution, 1.43 g (6.58 mmol) of CA-1 was added, 2.8 g of NMP was added, and then the polyamic acid solution (PAA-1) was obtained by stirring for 12 hours under conditions of 50 ° C. got The viscosity of this polyamic acid solution at 25° C. was 250 mPa·s.

[Example 5]
Synthesis of polyamic acid solution (PAA-2) After adding 2.36 g (7 mmol) of (DA-1-1) to a 50 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, add 24.6 g of NMP, nitrogen was stirred while feeding to dissolve. While stirring this diamine solution, 0.61 g (2.8 mmol) of CA-1 and 0.75 g (3.9 mmol) of CA-2 were added, and after adding 2.7 g of NMP, the mixture was further stirred at 50° C. for 12 hours. A polyamic acid solution (PAA-2) was obtained by stirring. The viscosity of this polyamic acid solution at 25° C. was 230 mPa·s.

[Comparative Example 1]
Synthesis of polyamic acid solution (PAA-3) Add 5.73 g (20 mmol) of (DA-2) to a 100 ml four-necked flask equipped with a stirring device and a nitrogen inlet tube, add NMP 65.1 g, and stir while sending nitrogen. and dissolved. After adding 4.14 g (19 mmol) of CA-1 while stirring this diamine solution, 7.2 g of NMP was added, and then the polyamic acid solution (PAA-3) was obtained by stirring for 18 hours under room temperature conditions. Obtained. The viscosity of this polyamic acid solution at 25° C. was 500 mPa·s.

[Comparative Example 2]
Synthesis of polyamic acid solution (PAA-4) After adding 1.98 g (10 mmol) of (DA-3) to a 50 ml four-neck flask equipped with a stirrer and a nitrogen inlet tube, 26.0 g of NMP was added, and nitrogen was sent. The solution was dissolved by stirring while stirring. While stirring this diamine solution, 0.87 g (4.0 mmol) of CA-1 and 1.08 g (5.5 mmol) of CA-2 were added, and after adding 2.9 g of NMP, the mixture was further stirred at 50° C. for 12 hours. A polyamic acid solution (PAA-4) was obtained by stirring. The viscosity of this polyamic acid solution at 25° C. was 300 mPa·s.

[Example 6]
Preparation of liquid crystal aligning agent (Q-1) 7.5 g of the polyamic acid solution (PAA-1) obtained in Example 4 was taken, and while stirring, NMP 5.6 g, BCS 6.0 g, 3-aminopropyltriethoxy 0.9 g of an NMP solution containing 1% by weight of silane was added and stirred at room temperature for 2 hours to obtain a liquid crystal aligning agent (Q-1).

[Example 7]
Preparation of liquid crystal aligning agent (Q-2) 7.5 g of the polyamic acid solution (PAA-2) obtained in Example 5 was separated, and while stirring, NMP 5.6 g, BCS 6.0 g, 3-aminopropyltriethoxy 0.9 g of an NMP solution containing 1% by weight of silane was added and stirred at room temperature for 2 hours to obtain a liquid crystal aligning agent (Q-2).

[Comparative Example 3]
Preparation of liquid crystal aligning agent (Q-3) 7.5 g of the polyamic acid solution (PAA-3) obtained in Comparative Example 1 was taken, and while stirring, NMP 5.6 g, BCS 6.0 g, 3-aminopropyltriethoxy 0.9 g of an NMP solution containing 1% by weight of silane was added, and the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal aligning agent (Q-3).

[Comparative Example 4]
Preparation of liquid crystal aligning agent (Q-4) 7.5 g of the polyamic acid solution (PAA-4) obtained in Comparative Example 2 was taken, and while stirring, NMP 5.6 g, BCS 6.0 g, 3-aminopropyltriethoxy 0.9 g of an NMP solution containing 1% by weight of silane was added, and the mixture was further stirred at room temperature for 2 hours to obtain a liquid crystal aligning agent (Q-4).

[Production of liquid crystal cell for ion density measurement]
After filtering the liquid crystal aligning agent with a 1.0 μm filter, a substrate with electrodes (a glass substrate with a size of 30 mm wide × 40 mm long and a thickness of 1.1 mm. The electrodes are rectangular with a width of 10 mm × length of 40 mm, 35 nm thick ITO electrode) was applied by a spin coating method. After drying on a hot plate at 50° C. for 5 minutes, baking was performed in an IR oven at 230° C. for 20 minutes to form a coating film having a thickness of 100 nm to obtain a substrate with a liquid crystal alignment film. After rubbing this liquid crystal alignment film with a rayon cloth (Yoshikawa Kako YA-20R) (roller diameter: 120 mm, roller rotation speed: 1000 rpm, moving speed: 20 mm / sec, pushing length: 0.4 mm), in pure water After washing by ultrasonic irradiation for 1 minute, water droplets were removed by an air blow, the substrate was dried at 80° C. for 15 minutes to obtain a substrate with a liquid crystal alignment film.

Prepare two substrates with the above liquid crystal alignment film, sprinkle a 4 μm spacer on the surface of one of the liquid crystal alignment films, then print a sealing material from above, and rub the other substrate in the opposite direction. After laminating in such a way that the directions and film surfaces face each other, the sealing material is cured to prepare an empty cell. MLC-3019 (manufactured by Merck Ltd.) was injected into this empty cell by a vacuum injection method, and the injection port was sealed to obtain a liquid crystal cell. After that, the obtained liquid crystal cell was heated at 110° C. for 1 hour and allowed to stand at 23° C. overnight to obtain a liquid crystal cell for ion density measurement.

[Ion density measurement]
The ion density was measured for the liquid crystal cell produced by the method described in [Preparation of liquid crystal cell for ion density measurement] above. In the measurement of the ion density, the ion density was measured when a triangular wave with a voltage of ±10 V and a frequency of 0.01 Hz was applied to the liquid crystal cell. The measurement temperature was 60°C. A 6256-type liquid crystal physical property evaluation device manufactured by Toyo Technica Co., Ltd. was used as a measuring device. The ion density was measured after the liquid crystal cell was produced and after the liquid crystal cell was aged for 120 hours under high temperature and high humidity conditions of 60° C. and 90%. The ion density was measured for the liquid crystal cell produced using the liquid crystal aligning agent (Q-1) of Example 6 and the liquid crystal cell produced using the liquid crystal aligning agent (Q-3) of Comparative Example 3. did.

[Production of liquid crystal display element]
First, a substrate with electrodes was prepared. The substrate is a glass substrate with a size of 30 mm×35 mm and a thickness of 0.7 mm. An IZO electrode having a solid pattern is formed as a first layer on the substrate to form a counter electrode. 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 SiN film of the second layer has a film thickness of 500 nm and functions as an interlayer insulating film. On the SiN film of the second layer, a comb-shaped pixel electrode formed by patterning an IZO film is arranged as a third layer to form two pixels, a first pixel and a second pixel. ing. The size of each pixel is 10 mm long and about 5 mm wide. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated 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 V-shaped electrode elements with a bent central portion, as in the figure described in JP-A-2014-77845. . The width of each electrode element in the lateral direction is 3 μm, and the interval between electrode elements is 6 μm. Since the pixel electrode that forms each pixel is configured by arranging a plurality of V-shaped electrode elements with a bent central portion, the shape of each pixel is not rectangular, but the central portion is the same as the electrode element. It has a shape resembling a bold, Chinese character that bends at the . Each pixel is vertically divided by the curved portion in the center, and has a first region above the curved portion and a second region below the curved 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, which will be described later, is used as a reference, the electrode element of the pixel electrode is formed to form an angle of +10° (clockwise) in the first region of the pixel, and the pixel in the second region of the pixel. The electrode elements of the electrode are formed at an angle of -10° (clockwise). That is, in the first region and the second region of each pixel, the directions of the rotational movement (in-plane switching) of the liquid crystal induced by the voltage application between the pixel electrode and the counter electrode in the plane of the substrate are mutually different. It is configured to be in the opposite direction.

Next, after filtering the obtained liquid crystal aligning agent with a 1.0 μm filter, the prepared substrate with electrodes and a columnar spacer having a height of 4 μm on which an ITO film is formed on the back surface as a counter substrate. was spin-coated onto each of the glass substrates with Then, after drying on a hot plate at 80° C. for 5 minutes, it was baked at 230° C. for 20 minutes to obtain a polyimide film on each substrate as a coating film having a thickness of 60 nm. After rubbing the polyimide film with a rayon cloth in a predetermined rubbing direction (roll diameter 120 mm, rotation speed 500 rpm, moving speed 30 mm/sec, pushing amount 0.3 mm), ultrasonic irradiation in pure water for 1 minute. and dried at 80° C. for 10 minutes.

After that, using the above-described two types of substrates with liquid crystal alignment films, they were combined so that their rubbing directions were antiparallel, and the periphery was sealed except for the liquid crystal injection port, and an empty cell with a cell gap of 3.8 μm was formed. made. Liquid crystal (MLC-3019, manufactured by Merck & Co., Ltd.) was vacuum-injected into this empty cell at normal temperature, and then the injection port was sealed to form an anti-parallel aligned liquid crystal cell. The obtained liquid crystal cell constitutes an FFS mode liquid crystal display device. After that, the obtained liquid crystal cell was heated at 120° C. for 1 hour and allowed to stand overnight before being used for each evaluation.

[Evaluation of stability of liquid crystal alignment]
Using this liquid crystal cell, an AC voltage of 10 VPP was applied at a frequency of 30 Hz for 168 hours in a constant temperature environment of 60°C. After that, the pixel electrode and the counter electrode of the liquid crystal cell were short-circuited and left at room temperature for one day. After standing, the liquid crystal cell was placed between two polarizing plates arranged so that the polarizing axes were perpendicular to each other, and the backlight was turned on with no voltage applied so that the brightness of the transmitted light was minimized. The arrangement angle of the liquid crystal cell was adjusted. Then, the rotation angle when the liquid crystal cell was rotated from the angle at which the second region of the first pixel was the darkest to the angle at which the first region was the darkest was calculated as the angle Δ. Similarly, for the second pixel, the second region and the first region were compared to calculate a similar angle Δ. Then, the average value of the angle Δ values of the first pixel and the second pixel was calculated as the angle Δ of the liquid crystal cell. A liquid crystal cell having an angle Δ of 0.15° or less was evaluated as good, and a liquid crystal cell having an angle Δ of more than 0.15° was evaluated as poor.

[Relaxation characteristics of accumulated charges]
The liquid crystal cell is placed between two polarizing plates arranged so that the polarization axes are orthogonal, and the pixel electrode and the counter electrode are shorted to the same potential. The backlight was illuminated, and the angle of the liquid crystal cell was adjusted so that the brightness of the light transmitted through the LED backlight measured on the two polarizing plates was minimized. Next, while applying a rectangular wave with a frequency of 30 Hz to this liquid crystal cell, the VT characteristic (voltage-transmittance characteristic) was measured at a temperature of 23° C., and an AC voltage at which the relative transmittance was 23% was applied. Calculated. Since this AC voltage corresponds to a region in which the change in luminance with respect to voltage is large, it is convenient for evaluating accumulated charges via luminance.

Next, after applying a rectangular wave with a frequency of 30 Hz at an AC voltage with a relative transmittance of 23% for 5 minutes, a DC voltage of +1.0 V was superimposed and driven for 30 minutes. After that, the DC voltage was turned off, and only the AC voltage with the relative transmittance of 23% and the rectangular wave with the frequency of 30 Hz was applied for 30 minutes. The faster the relaxation of the accumulated charges, the faster the charge accumulation in the liquid crystal cell when the DC voltage is superimposed. It was evaluated by the time required to decrease from 23% to 23%. The shorter this time is, the better the relaxation characteristic of accumulated charge is.

<Examples 1 to 4>
Using the liquid crystal aligning agents Q1 to Q4 of Examples 6 to 7 and Comparative Examples 3 to 4, ion density measurement, stability evaluation of liquid crystal alignment, and evaluation of accumulated charge relaxation characteristics were performed. Table 1 shows the results. In the table, the liquid crystal cells produced using the liquid crystal aligning agents Q1 and Q2 are designated as Examples 8 and 9, respectively, and the liquid crystal cells produced using the liquid crystal aligning agents Q3 and Q4 are designated as Comparative Examples 5 and 6, respectively.

INDUSTRIAL APPLICABILITY The liquid crystal alignment film of the present invention can provide display performance excellent in afterimage properties and contrast particularly in IPS drive system and FFS drive system liquid crystal display elements that require rubbing treatment. Therefore, it is particularly useful as a liquid crystal alignment film used for IPS drive system or FFS drive system liquid crystal display elements, multifunctional mobile phones (smartphones), tablet personal computers, liquid crystal televisions, and the like.

Claims (8)

A diamine having a structure represented by the following formula (1).

R represents a hydrogen atom or a monovalent organic group, R ¹ represents a hydrogen atom or an alkyl group or aryl group having 1 to 5 carbon atoms, which may be linear or branched, and two are present on the same maleimide ring. R ¹ may be the same or different, two R ¹ may be bonded together to form an alkylene having 3 to 6 carbon atoms, and W ¹ represents a single bond or a divalent organic group. , W ² represents a divalent organic group, Ar ¹ represents an aromatic ring, and L ¹ represents a single bond, carbonyl, sulfonyl or alkylene having 1 to 20 carbon atoms. 2. The diamine according to claim 1, wherein W1 in formula ( ¹ ) is a single bond. 3. The diamine according to claim 1, wherein said Ar ¹ is a 1,3-phenylene group or a 1,4-phenylene group. A diamine according to any one of claims 1 to 3, wherein said R represents a monovalent organic group. A polymer obtained from a diamine having a structure represented by the following formula (1).

R represents a hydrogen atom or a monovalent organic group, R ¹ represents a hydrogen atom or an alkyl group or aryl group having 1 to 5 carbon atoms, which may be linear or branched, and two are present on the same maleimide ring. R ¹ may be the same or different, two R ¹ may be bonded together to form an alkylene having 3 to 6 carbon atoms, and W ¹ represents a single bond or a divalent organic group. , W ² represents a divalent organic group, Ar ¹ represents an aromatic ring, and L ¹ represents a single bond, carbonyl, sulfonyl or alkylene having 1 to 20 carbon atoms. 6. The polymer according to claim 5, wherein W1 in formula ( ¹ ) is a single bond. 7. The polymer according to claim 5, wherein Ar ¹ in formula (1) is a 1,3-phenylene group or a 1,4-phenylene group. A polymer according to any one of claims 5 to 7, wherein said R represents a monovalent organic group.