TW201843297A - Liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display element - Google Patents

Abstract

A liquid crystal aligning agent which contains a polymer that is obtained from a diamine having a structure represented by formula (1). In the formula, R1 represents a hydrogen atom, a linear or branched alkyl group having 1-5 carbon atoms or an aryl group; two R1 moieties present on a same maleimide ring may be the same as or different from each other, and the two R1 moieties may combine together to form an alkylene group having 3-6 carbon atoms; W2 represents a divalent organic group; W1 represents a single bond or a carbonyl group; L1 represents a linear alkylene group having 1-20 carbon atoms, a branched alkylene group having 3-20 carbon atoms, a cyclic alkylene group having 3-20 carbon atoms, a divalent group selected from among a phenylene group and a heterocyclic group, or a group obtained by combining a plurality of the divalent groups; the phenylene group and the heterocyclic group may be independently substituted by one or more, and same or different substituents selected from among an alkyl group, an alkoxy group, a haloalkyl group, a haloalkoxy group, a halogen group and a cyano group; the bond between the divalent groups is at least one bond selected from among a single bond, an ester bond, an amide bond, a urea bond, an ether bond, a thioether bond, an amino bond and a carbonyl group; in cases where there are a plurality of the divalent groups, the divalent groups may be the same as or different from each other; in cases where there are a plurality of the bonds, the bonds may be the same as or different from each other; R represents a hydrogen atom or a monovalent organic group; two R moieties may be the same as or different from each other, and the two R moieties may combine together to form an alkylene group having 1-6 carbon atoms; and both or one of the two R moieties may be bonded to L1.

Description

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

The present invention relates to a polyamic acid, a polyamidate, a polyimide, a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display element. The polyamino acid is a polymer useful as a liquid crystal alignment film The raw material is a novel diamine compound (also referred to as a diamine in the present invention).

Liquid crystal display elements have conventionally used display units such as personal computers, mobile phones, and television receivers. As their driving methods, vertical electric field methods such as the TN method and VA method, or IPS methods and fringe electric field switching (Fringe) Field Switching: Horizontal electric field method such as FFS method.

In general, a transverse electric field method in which electrodes are formed on only one side of a substrate and an electric field is applied in a direction parallel to the substrate is compared with a longitudinal electric field method in which liquid crystal is driven by applying a voltage to electrodes formed on upper and lower substrates. It is easier to obtain a liquid crystal display element with wide viewing angle characteristics and high-quality display. As a method for aligning the liquid crystal in a fixed direction, for example, there is a method of forming a polymer film such as polyimide on a substrate and wiping the surface with a cloth, which is a so-called rubbing method.

Examples of conventional problems include improving the voltage retention rate or improving the charge accumulation caused by the applied DC voltage component that originates from the active array structure. If the electric charge accumulates in the liquid crystal display element, it will be caused by the disorder of the liquid crystal alignment or the afterimage, which will adversely affect the display and cause the display quality of the liquid crystal display element to be significantly reduced. Or, when driving in a state where the charge has been accumulated, immediately after the driving, the control of the liquid crystal molecules cannot be performed normally, resulting in flicker and the like.

Moreover, as a characteristic required for a liquid crystal alignment film in order to improve the display quality of a liquid crystal display element, an ion density is mentioned. When the ion density is high, the voltage applied to the liquid crystal is reduced, and as a result, the brightness may be reduced, which may cause a problem in normal-level display. In addition, even if the initial ion density is low, the ion density may increase after the high temperature accelerated test. Such a decrease in long-term reliability or occurrence of an afterimage caused by residual charges or ionic impurities will reduce the display quality of the liquid crystal.

In response to the above-mentioned requirements, various proposals have been made in polyimide-based liquid crystal alignment films. For example, as one of the liquid crystal alignment films for the purpose of shortening the time until the afterimage caused by a DC voltage disappears, it has been proposed to use a polyamic acid other than polyamic acid or polyimide containing polyimide, A liquid crystal alignment agent containing a tertiary amine with a specific structure (for example, refer to Patent Document 1) or a liquid crystal alignment agent containing a soluble polyfluorene imine using a specific diamine compound having a pyridine skeleton or the like as a raw material ( For example, refer to Patent Document 2). [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Laid-Open No. 9-316200 [Patent Document 2] Japanese Patent Application Laid-Open No. 10-104633

[Problems to be Solved by the Invention]

As a method for aligning liquid crystals, rubbing treatment is widely used in industry. However, due to the difference in the liquid crystal alignment film used, the rubbing direction may be inconsistent with the alignment direction of the liquid crystal, that is, a phenomenon called a twist angle occurs. . That is, the horizontal electric field element exhibits black display in a state where no voltage is applied, but because this phenomenon results in an increase in brightness even in a state where no voltage is applied, the result still causes a problem that the display contrast decreases.

The present invention aims to provide a liquid crystal alignment film, a liquid crystal alignment agent capable of obtaining such a liquid crystal alignment film, and a liquid crystal display element including the liquid crystal alignment film. The liquid crystal alignment film can suppress the liquid crystal display from being depressed. The density of ions in the device and the rapid relaxation of the accumulated charge, in particular, can suppress the deviation between the friction direction and the alignment direction of the liquid crystal, which is a problem in the transverse electric field driving method. [Means to solve the problem]

As a result of careful research by the present inventors in order to solve the above-mentioned problems, it has been found that by introducing a specific structure to a polymer included in the liquid crystal alignment agent, various characteristics can be simultaneously improved, and the present invention has been completed. The present invention is based on this knowledge, and the following is the gist.

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

R ¹ represents a hydrogen atom, a linear or branchable alkyl or aryl group having 1 to 5 carbon atoms, and two R ¹ on the same maleimide ring may be the same as or different from each other, 2 Each R ¹ can also form an alkylene group having 3 to 6 carbon atoms, W ² represents a divalent organic group, W ¹ represents a single bond or a carbonyl group, and L ¹ represents a linear alkylene group selected from carbon atoms 1 to 20 , Branched alkylene groups of 3 to 20 carbon atoms, cyclic alkylene groups of 3 to 20 carbon atoms, diphenyl groups of phenylene and heterocyclic groups, or groups formed by plural bonding of the divalent groups The phenylene and heterocyclic groups are each independently and may be substituted by one or more substituents which are the same or different and are selected from the group consisting of alkyl, alkoxy, haloalkyl, haloalkoxy, halo and cyano. Substituting, the bonding of the divalent groups to each other is at least one selected from the group consisting of a single bond, an ester bond, a amine bond, a urea bond, an ether bond, a thioether bond, an amine bond, and a carbonyl group. When the divalent group is plural, The divalent radicals may be the same as or different from each other. When the above-mentioned bonding is plural, the bondings may be the same or different from each other. R represents a hydrogen atom or a monovalent organic group, and two Rs may be different from each other. , 2 R can also form an alkylene group with 1 to 6 carbon atoms together R 2 or any one of the two may be bonded to L ^1.

2. The liquid crystal alignment agent according to 1., wherein the aforementioned W ¹ represents a single bond.

3. The liquid crystal alignment agent according to 1. or 2., wherein the polymer is a polyimide selected from the group consisting of a polyimide precursor containing a structural unit represented by the following formula (3), and a polyimide At least one of them.

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 a structure of formula (1), and R ⁴ represents a hydrogen atom or an alkane having 1 to 5 carbon atoms base.

4. The liquid crystal alignment agent according to 3., wherein in the foregoing formula (3), the structure of X ¹ represents at least one selected from the following structures.

5. The liquid crystal alignment agent according to 3., wherein the aforementioned polymer is at least one selected from the group consisting of a polyimide precursor that further includes a structural unit represented by the following formula (4), and a polyimide of a sulfonium imide. One.

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

6. The liquid crystal alignment agent according to 5., wherein the aforementioned Y ² is represented by the following formula (11).

In formula (11), 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- Non-adjacent conditions can also be replaced by ether, ester, amidine, urea, carbamate bonds. R ³⁴ represents a single bond or a divalent organic group. Any hydrogen atom on the benzene ring may be substituted by a monovalent organic group.

7. The liquid crystal alignment agent according to 4. or 5., wherein the structural unit represented by the aforementioned formula (3) is 10 mol% or more with respect to the entire structural unit of the polymer.

8. A liquid crystal alignment film comprising a liquid crystal alignment agent according to any one of 1. to 7.

9. A liquid crystal display element, which is provided with the liquid crystal alignment film as in 8.

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

R ¹ represents a hydrogen atom, a linear or branchable alkyl or aryl group having 1 to 5 carbon atoms, and two R ¹ on the same maleimide ring may be the same as or different from each other, 2 Each R ¹ can also form an alkylene group having 3 to 6 carbon atoms, W ² represents a divalent organic group, W ¹ represents a single bond or a carbonyl group, and L ¹ represents a linear alkylene group selected from carbon atoms 1 to 20 , Branched alkylene groups of 3 to 20 carbon atoms, cyclic alkylene groups of 3 to 20 carbon atoms, diphenyl groups of phenylene and heterocyclic groups, or groups formed by plural bonding of the divalent groups The phenylene and heterocyclic groups are each independently and may be substituted by one or more substituents which are the same or different and are selected from the group consisting of alkyl, alkoxy, haloalkyl, haloalkoxy, halo and cyano. Substituting, the bonding of the divalent groups to each other is at least one selected from the group consisting of a single bond, an ester bond, a amine bond, a urea bond, an ether bond, a thioether bond, an amine bond, and a carbonyl group. When the divalent group is plural, The divalent radicals may be the same as or different from each other. When the above-mentioned bonding is plural, the bondings may be the same or different from each other. R represents a hydrogen atom or a monovalent organic group, and two Rs may be different from each other. , 2 R can also form an alkylene group with 1 to 6 carbon atoms together R 2 or any one of the two may be bonded to L ^1.

11. A polymer, which is formed using a diamine such as 10. [Effect of the invention]

By using the liquid crystal alignment agent containing the polymer of the present invention, it is possible to suppress the reduction of the ion density in the liquid crystal display element, and to rapidly alleviate the accumulated charge, especially to suppress the friction that is a problem in the transverse electric field driving method. A liquid crystal alignment film having a deviation between a direction and an alignment direction of the liquid crystal. It is inconclusive as to why the above-mentioned problems can be solved by the present invention, and it is roughly considered as follows. The structure of the above formula (1) contained in the polymer of the present invention has a nitrogen atom. Thereby, for example, in the liquid crystal alignment film, the ability to capture ionic impurities can be provided, and the movement of electric charges can be promoted, so that the accumulated electric charges can be relaxed.

The liquid crystal alignment agent of the present invention is a liquid crystal alignment agent containing a polymer (hereinafter also referred to as a specific polymer) obtained from a diamine having a structure represented by the formula (1) (hereinafter also referred to as a specific structure). Hereinafter, each condition will be described in detail.

<Diamine having a specific structure> In the above formula (1), R ¹ represents a hydrogen atom, a linear or branchable alkyl or aryl group having 1 to 5 carbon atoms, and 2 on the same maleimide ring Each R ¹ may be the same as or different from each other. Two R ¹ may also form an alkylene group having 3 to 6 carbon atoms, W ² represents a divalent organic group, and L ¹ represents a single bond or 1 to 20 carbon atoms. R is an alkylene group, R represents a hydrogen atom or a monovalent organic group, 2 Rs may be different from each other, or 2 Rs together may form an alkylene group having 1 to 6 carbon atoms, or two or both of Rs. Alternatively, it may be bonded to L ¹ .

R ^{1 is} preferably a hydrogen atom, a methyl group, an ethyl group, an iso-propyl group, or a phenyl group, and more preferably a hydrogen atom, a methyl group, and a phenyl group. Further, as the alkylene group having 3 to 6 carbon atoms formed by two R ¹ together,-(CH ₂ ) ₃ -,-(CH ₂ ) _4- , and-(CH ₂ ) ₅ -are preferred, and more preferably -(CH ₂ ) _4- .

The alkylene group having 1 to 20 carbon atoms in the definition of L ¹ may be linear or branched, and examples thereof include-(CH ₂ ) _n- (where n is 1 to 20). Linear alkylene, or 1-methylmethane-1,1-diyl, 1-ethylmethane-1,1-diyl, 1-propylmethane-1,1-diyl, 1-methyl Ethane-1,2-diyl, 1-ethylethane-1,2-diyl, 1-propylethane-1,2-diyl, 1-methylpropane-1,3-di Base, 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 Alkane-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- Hexane-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-methylheptane-1,7-diyl, 1-phenylmethane Branched alkylene groups such as -1,1-diyl, 1-phenylethane-1,2-diyl, 1-phenylpropane-1,3-diyl and the like. Under the condition that the oxygen atom or sulfur atom is not adjacent to each other, the linear or branched alkylene group may be interrupted by the oxygen atom or sulfur atom 1 to 5 times.

Examples of the branched alkylene group having 3 to 20 carbon atoms in the definition of L ¹ include i-butylene, i-butylene, s-butylene, t-butylene, 1 -Methyl-n-butylene, 2-methyl-n-butylene, 3-methyl-n-butylene, 1,1-dimethyl-n-butylene, 1,2- Dimethyl-n-propyl, 2,2-dimethyl-n-propyl, 1-ethyl-n-propyl, 1-methyl-n-pentyl, 2-methyl -n-pentyl, 3-methyl-n-pentyl, 4-methyl-n-pentyl, 1,1-dimethyl-n-butyl, 1,2-dimethyl -n-butylene, 1,3-dimethyl-n-butylene, 2,2-dimethyl-n-butylene, 2,3-dimethyl-n-butylene, 3 1,3-dimethyl-n-butylene, 1-ethyl-n-butylene, 2-ethyl-n-butylene, 1,1,2-trimethyl-n-butylene , 1,2,2-trimethyl-n-propyl, 1-ethyl-1-methyl-n-propyl and 1-ethyl-2-methyl-n-propyl In addition, for example, an alkylene group having a carbon number of up to 20 and branching at an arbitrary place can be mentioned.

Examples of the cyclic alkylene group having 3 to 20 carbon atoms in the definition of L ¹ include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclohexyl Monocyclic alkylene groups such as octyl, and polycyclic alkylene groups such as norbornyl, tricyclodecyl, tetracyclododecyl, and adamantyl.

Examples of the substituent when the benzene ring in the definition of L ¹ may be substituted with a substituent include alkyl groups such as methyl, ethyl, propyl, butyl, and isobutyl; trifluoromethyl and the like Haloalkyl; alkoxy groups such as methoxy and ethoxy; halogen atoms such as iodine, bromine, chlorine, fluorine; cyano.

As R, a hydrogen atom or a linear alkyl group having 1 to 3 carbon atoms is preferred, and a hydrogen atom or a methyl group is preferred. In addition, R may be a protective group which is detached due to heat and is replaced by a hydrogen atom. From the viewpoint of storage stability of the liquid crystal alignment agent, a protective group which does not detach at room temperature and is detached by heat above 80 ° C is Preferably, a protecting group that is released by heat above 100 ° C is preferred. Examples thereof include 1,1-dimethyl-2-chloroethoxycarbonyl, 1,1-dimethyl-2-cyanoethoxycarbonyl, tert-butoxycarbonyl, and tert -Butoxycarbonyl is preferred.

In addition, as an alkylene group having 3 to 6 carbon atoms, which is formed by two Rs, -CH ₂ -,-(CH ₂ ) ₂ -,-(CH ₂ ) ₃ -,-(CH ₂ ) ₄ -,- (CH _{2) 5} - preferably, preferably - (CH _{2) 2} - or - (CH _{2) 3} -. The divalent organic group W ² is represented by the following formulas [W ² -1] to [W ² -152].

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

<The manufacturing method of a specific diamine> The method of obtaining the said diamine is demonstrated below. Among the specific diamines represented by the formula (1) of the present invention, the method for synthesizing a diamine in which W ¹ is a single bond is not particularly limited, and examples thereof include a nitro horse represented by the following formula (A) A method in which a perylene imine compound is reacted with a diamine-based compound represented by the following formula (B1) to obtain an amino-nitro compound represented by the following formula (C1) and reduced.

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

The amount of the compound represented by the formula (B1) is preferably 0.1 mol to 1 mol, and more preferably 0.4 mol to 0.5 mol relative to 1 mol of the compound represented by the formula (A). By making the compound represented by the formula (A) into an excessive amount, the reaction can be smoothly performed and by-products can be suppressed.

This reaction is preferably performed in a solvent. The solvent can be used without limitation as long as it is a solvent which does not react with each raw material. For example, aprotic polar organic solvents (DMF, DMSO, DMAc, NMP, etc.); ethers (Et ₂ O, i-Pr ₂ O, TBME, CPME, THF, dioxane, etc.); aliphatic hydrocarbons (Pentane, hexane, heptane, petroleum ether, etc.); aromatic hydrocarbons (benzene, toluene, stubble, mesitylene, chlorobenzene, dichlorobenzene, nitrobenzene, tetrahydronaphthalene, etc.); halogenated hydrocarbons (Chloroform, methylene chloride, carbon tetrachloride, dichloroethane, etc.); lower fatty acid esters (methyl acetate, ethyl acetate, butyl acetate, methyl propionate, etc.); nitriles (acetonitrile, propane Nitrile, butyronitrile, etc.). These solvents may be appropriately selected in consideration of the ease of causing the reaction, and may be used alone or in combination of two or more. If necessary, the solvent may be dried using a suitable dehydrating agent or desiccant, and used as a non-aqueous solvent.

The use amount (reaction concentration) of the solvent is not particularly limited, and it is 0.1 to 100 times by mass based on the bismaleimide compound. It is preferably from 0.5 mass times to 30 mass times, and more preferably from 1 mass times to 10 mass times. The reaction temperature is not particularly limited. The range from -100 ° C to the boiling point of the solvent used is preferably -50 to 150 ° C. The reaction time is usually from 0.05 hours to 350 hours, and preferably from 0.5 hours to 100 hours.

This reaction can be carried out in the presence of an inorganic base or an organic base as necessary. As the base used in the reaction, an inorganic base such as sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium bicarbonate, potassium bicarbonate, potassium gallate, sodium carbonate, potassium carbonate, lithium carbonate, cesium carbonate, etc. can be used; tert -Bases of sodium butoxylate, tert-butoxypotassium, sodium hydride, potassium hydride, etc .; trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine, diiso An amine such as propylethylamine, pyridine, quinoline, collidine and the like. Among them, triethylamine, pyridine, tert-butoxy sodium, tert-butoxy potassium, sodium hydride, potassium hydride and the like are preferred. The use amount of the base is not particularly limited, but it is 0.1 to 100 parts by mass based on the bismaleimide compound. It is preferably 0 to 30 times by mass, and more preferably 0 to 10 times by mass.

One aspect of the compound (B1) is a compound represented by the following formula (B1-1) where L ¹ is a divalent organic group, R is a hydrogen atom, and W ¹ is a single bond.

The R systems in the formula (B1-1) are each independently a hydrogen atom or a monovalent organic group, and a hydrogen atom or a linear alkyl group having 1 to 3 carbon atoms is preferred. Examples of L ¹ of the compound of the formula (B1-1) include a structure selected from the above W ² -1 to W ² -152. It is preferable to select from the following structures, but it is not limited to them.

One aspect of the compound (B1) is that L ¹ is a divalent organic group, W ¹ is a single bond, R forms an alkylene group together, or two R are bonded to L ¹ together with the following formula (B1-2) The compound shown.

The compound of the formula (B1-2) is preferably a structural formula selected from the following.

One aspect of the compound (B1) is a compound represented by the following formula (B1-3) in which L ¹ is a divalent organic group, W ¹ is a single bond, and one of R is bonded to L ¹ to form a ring.

The R systems in the formula (B1-3) are each independently a hydrogen atom or a monovalent organic group, preferably a hydrogen atom or a linear alkyl group having 1 to 3 carbon atoms. As a compound of a formula (B1-3), the following are mentioned preferably.

Next, the conditions for producing a specific diamine represented by the formula (1) by reducing the compound represented by the formula (C1) will be 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 a salt thereof and a proton. The amount of Fe, Sn, Zn, or these salts used is preferably 1 to 100 equivalents, and particularly preferably 3 to 50 equivalents relative to the compound represented by the formula (1).

As the reaction solvent, 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, tert-butyl alcohol, etc .; dimethylformamide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone And other aprotic polar organic solvents; diethyl ether, diisopropyl ether, tert-butyl methyl ether, cyclopentyl methyl ether, tetrahydrofuran, dioxane and other ethers; pentane, hexane, and heptane Aliphatic hydrocarbons such as petroleum ether, petroleum ether; aromatic hydrocarbons such as benzene, toluene, stub, mesitylene, tetrahydronaphthalene, halogenated hydrocarbons such as chloroform, dichloromethane, carbon tetrachloride, and dichloroethane; acetic acid; Lower fatty acid esters of methyl ester, ethyl acetate, butyl acetate, methyl propionate, etc .; nitriles such as acetonitrile, propionitrile, butyronitrile. These solvents can be appropriately selected in consideration of the ease of causing the reaction, etc., and can be used alone or in combination of two or more. In some cases, the solvent may be used as a solvent containing no water by using an appropriate dehydrating agent or desiccant. The use amount (reaction concentration) of the solvent is not particularly limited, but it is 0.1 to 100 mass times based on the compound represented by the formula (C1). It is preferably 0.5 mass times to 50 mass times, and more preferably 3 mass times to 30 mass times.

In order to make the reaction proceed more efficiently, the reaction may be carried out under pressure. In this case, in order to avoid reduction of the benzene nucleus, it is preferable to carry out the reaction under a pressure range of about 20 atmospheres (kgf), and it is preferable to carry out the reaction in a range up to 10 atmospheres. In addition, acids such as hydrochloric acid, sulfuric acid, formic acid, acetic acid, and the salts thereof can coexist. The use amount of these is not particularly limited, and it is 0 to 10 times by mass based on the compound represented by the formula (C1). 0 mass times to 5 mass times is preferred, and more preferably 0 mass times to 3 mass times. The reaction temperature can be selected from a temperature range of -100 ° C or higher to the temperature of the boiling point of the reaction solvent used, preferably -50 ° C to 150 ° C, and particularly preferably 0 ° C to 100 ° C. The reaction time is from 0.1 hours to 1000 hours, and preferably from 1 hour to 200 hours. As a method for reducing the compound represented by the above formula (C1), there are a hydrogenation reaction using palladium-activated carbon or platinum-activated carbon as a catalyst, a reduction reaction using formic acid as a hydrogen source, and thorium as a hydrogen source Reaction, etc. A combination of these reactions can also be performed.

The catalyst used for the reduction reaction is preferably a commercially available activated carbon-supporting metal, and examples thereof include palladium-activated carbon, platinum-activated carbon, and rhodium-activated carbon. In addition, palladium hydroxide, platinum oxide, Raney nickel, etc. do not necessarily need to be activated carbon-supporting metal catalysts. Since generally widely used palladium-activated carbon or platinum-activated carbon can give good results, it is preferable.

The amount of these catalysts used may be a so-called catalyst amount, and it is preferably 20 mol% or less, and particularly preferably 10 mol% or less with respect to the compound represented by the formula (C1).

As the reaction solvent, any solvent can be used as long as it does not hinder the intended reaction under the reaction conditions. For example, alcohol solvents such as methyl alcohol, ethyl alcohol, tert-butyl alcohol, and the like; dimethylformamide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, and the like can be used. Aprotic polar organic solvents; diethyl ether, isopropyl ether, tert-butyl methyl ether, cyclopentyl methyl ether, tetrahydrofuran, dioxane and other ethers; pentane, hexane, heptane, petroleum ether And other aliphatic hydrocarbons; aromatic hydrocarbons such as benzene, toluene, stub, mesitylene, and tetralin; halogenated hydrocarbons such as chloroform, methylene chloride, carbon tetrachloride, and dichloroethane; methyl acetate, Lower fatty acid esters such as ethyl acetate, butyl acetate, and methyl propionate; nitriles such as acetonitrile, propionitrile, and butyronitrile. These solvents can be appropriately selected in consideration of the ease of causing the reaction, etc., and can be used alone or in combination of two or more. In some cases, the solvent may be used as a solvent containing no water by using an appropriate dehydrating agent or desiccant. The use amount (reaction concentration) of the solvent is not particularly limited, but it is 0.1 to 100 mass times based on the compound represented by the formula (C1). It is preferably 0.5 mass times to 50 mass times, and more preferably 3 mass times to 30 mass times. The reaction temperature is not particularly limited. For example, the range from -100 ° C to the boiling point of the solvent used is preferably -50 ° C to 150 ° C. The reaction time is usually from 0.05 hours to 350 hours, and preferably from 0.5 hours to 100 hours.

In order to make the reduction reaction proceed more efficiently, the reaction may be carried out in the coexistence of activated carbon. At this time, the amount of activated carbon to be used is not particularly limited, and it is preferably in the range of 1 to 30% by mass, and more preferably 10 to 20% by mass relative to the dinitro compound C1. For the same reason, the reaction may be performed under pressure. In this case, in order to avoid reduction of the benzene nucleus, it is performed in a pressure range up to 20 atmospheres. The reaction is preferably performed within a range of 10 atmospheres. Among the reduction reactions exemplified above, when considering the structure of the compound represented by the formula (C1) and the reactivity of the reduction reaction, it is preferable to use a hydrogenation reaction.

When an attempt is made to introduce a monovalent organic group as R, the compound in which R is a hydrogen atom in the dinitro compound represented by the above formula (C1) may be reacted with a compound capable of reacting with an amine. Examples of such compounds include acid halides, anhydrides, isocyanates, epoxy, propylene oxide, halogenated aryls, and halogenated alkyls. Alternatively, the hydroxy groups of alcohols can be replaced with OMs. OTf, OTs and other alcohols.

The method of introducing a monovalent organic group into the NH group is not particularly limited, and examples thereof include a method of reacting an acid halide in the presence of a suitable base. Examples of the acid halide include acetyl chloride, propionate chloride, methyl chloroformate, ethyl chloroformate, n-propyl chloroformate, i-propyl chloroformate, and n-butyl chloroformate. Esters, i-butyl chloroformate, t-butyl chloroformate, benzyl chloroformate, and 9-fluorenyl chloroformate. As an example of the base, the aforementioned base can be used. The reaction solvent and reaction temperature are based on the above description.

It is also possible to introduce a monovalent organic group by reacting an NH group with an acid anhydride. Examples of the acid anhydride include anhydrous acetic acid, anhydrous propionic acid, dimethyl dicarbonate, diethyl dicarbonate, and dicarbonate. Butyl ester, dibenzyl dicarbonate, and the like. To promote the reaction, a catalyst may be added, and pyridine, trimethylpyridine, N, N-dimethyl-4-aminopyridine, or the like may also be used. The amount of the catalyst is 0.0001 to 1 mole per mole of the dinitro compound represented by the above formula (C1) relative to 1 mole of the compound in which R is a hydrogen atom. The reaction solvent and reaction temperature are based on the above description.

A monovalent organic group may be introduced by reacting an NH group with an isocyanate. Examples of the isocyanate include methyl isocyanate, ethyl isocyanate, n-propyl isocyanate, and phenyl isocyanate. The reaction solvent and reaction temperature are based on the above description.

The NH group may be reacted with an epoxy compound or a propylene oxide compound to introduce a monovalent organic group. Examples of the epoxy or propylene oxide include ethylene oxide, propylene oxide, and 1 , 2-butylene oxide, trimethylene oxide, etc. The reaction solvent and reaction temperature are based on the above description.

It is also possible to introduce a monovalent organic group by reacting an NH group with a halogenated aryl group in the presence of a metal catalyst, a ligand, and a base. Examples of the halogenated aryl group include iodobenzene, bromobenzene, and chlorobenzene. Wait. Examples of the metal catalyst include palladium acetate, palladium chloride, palladium chloride-acetonitrile complex, palladium-activated carbon, bis (dibenzylideneacetone) palladium, and ginseno (dibenzylideneacetone). Dipalladium, bis (acetonitrile) dichloropalladium, bis (benzonitrile) dichloropalladium, CuCl, CuBr, CuI, CuCN, etc. are not limited by these. Examples of the ligand 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, tris Methyl phosphite, triethylphosphite, triphenylphosphite, tri-tert-butylphosphine, etc. are not limited by these. As an example of the base, the aforementioned base can be used. The reaction solvent and reaction temperature are based on the above description.

A monovalent organic group may also be introduced by reacting an NH group with an alcohol in which the hydroxyl group of the alcohol is replaced with a leaving group such as OMs, OTf, and OTs in the presence of a suitable base. Examples of the alcohol include methanol, Ethanol, 1-propanol, and the like can be substituted into OMs, OTf, and OTs by reacting these alcohols with methanesulfonyl chloride, trifluoromethanesulfonyl chloride, and p-toluenesulfonic acid chloride. Wait for the free radical alcohol. Examples of the base include the aforementioned bases. The reaction solvent and reaction temperature are based on the above description.

A monovalent organic group may be introduced by reacting an NH group with a halogenated alkyl group in the presence of a suitable base. Examples of the halogenated alkyl group include methyl iodide, ethyl iodide, and n-propyl iodide. Methyl, methyl bromide, ethyl bromide, n-propyl bromide, and the like. As examples of the base, in addition to the aforementioned bases, metal alkoxides such as potassium-tert-butoxylate, sodium-tert-butoxylate, and the like can also be used. Reaction conditions such as a reaction solvent, a reaction temperature, and a reaction time are based on the foregoing description.

The amount of the compound capable of reacting with amines is 1.0 mole equivalent to 3.0 mole relative to 1.0 mole equivalent of the compound in which R is a hydrogen atom in the dinitro compound represented by the above formula (C). Ear equivalent. The range of 2.0 mol equivalent to 2.5 mol equivalent is preferred. The above-mentioned compounds capable of reacting with amines can be used alone or in combination. In addition, when an isomer derived from an asymmetry point exists in the diamine compound represented by the formula (1), each isomer and the mixture thereof are considered to be included in the formula (1). Of the diamine. In addition, when two R ¹ on the same maleimidine imine ring of formula (1) are different from each other, the substitution positions of R ¹ on the diamine compound represented by formula (1) are different, but in this case they are different. Structure and these mixtures are all considered to be included in the diamine represented by formula (1).

[Production method of formula (A)] The method of synthesizing a compound of formula (A) is not particularly limited, and examples thereof include reacting a commercially available nitroamine represented by the following formula (D) with an anhydrous maleic acid derivative. Method.

With respect to 1 mole of the nitroamine compound represented by formula (D), the amount of the anhydrous maleic acid derivative used is preferably 1 mole to 1.5 moles, and more preferably 1 mole to 1.2 moles. By making anhydrous maleic acid into an excess amount, the reaction can be smoothly performed and by-products can be suppressed. This reaction is preferably performed in a solvent. The solvent and reaction conditions are preferably the same as the production conditions of the compound (1). Among the specific diamines represented by the formula (1) of the present invention, as a method for synthesizing a diamine in which W ¹ is a single bond, an amine maleate represented by the following formula (E) may also be mentioned. A method for reacting an imine compound with a diamine compound represented by the above formula (B1-1).

The definitions of R, R ¹ , L ¹ and W ^{2 are} the same as those in the above formula (1). The amount of the compound represented by formula (B1-1) is preferably 0.1 mol to 1 mol, and more preferably 0.4 mol to 0.5 mol relative to 1 mol of the compound represented by formula (E). . By making the compound represented by formula (E) into an excessive amount, the reaction can be smoothly performed and by-products can be suppressed.

This reaction is preferably performed 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.); aliphatic hydrocarbons (Pentane, hexane, heptane, petroleum ether, etc.); aromatic hydrocarbons (benzene, toluene, stubble, mesitylene, chlorobenzene, dichlorobenzene, nitrobenzene, tetrahydronaphthalene, etc.); halogenated hydrocarbons (Chloroform, methylene chloride, carbon tetrachloride, dichloroethane, etc.); lower fatty acid esters (methyl acetate, ethyl acetate, butyl acetate, methyl propionate, etc.); nitriles (acetonitrile, propane Nitrile, butyronitrile, etc.). These solvents may be appropriately selected in consideration of the ease of causing the reaction, etc., and may be used alone or in combination of two or more. If necessary, a suitable dehydrating agent or desiccant can be used as a non-aqueous solvent to dry the solvent. The use amount (reaction concentration) of the solvent is not particularly limited, and it is 0.1 to 100 mass times based on the bismaleimide compound. It is preferably from 0.5 mass times to 30 mass times, and more preferably from 1 mass times to 10 mass times. The reaction temperature is not particularly limited. The range from -100 ° C to the boiling point of the solvent used is preferably -50 ° C to 150 ° C. The reaction time is usually from 0.05 hours to 350 hours, and preferably from 0.5 hours to 100 hours.

This reaction can be carried out in the presence of an inorganic base or an organic base as necessary. As the base used in the reaction, an inorganic base such as sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium bicarbonate, potassium bicarbonate, potassium gallate, sodium carbonate, potassium carbonate, lithium carbonate, cesium carbonate, etc. can be used; tert -Bases of sodium butoxylate, tert-butoxypotassium, sodium hydride, potassium hydride, etc .; trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine, diiso An amine such as propylethylamine, pyridine, quinoline, and trimethylpyridine. Among them, triethylamine, pyridine, tert-butoxy sodium, tert-butoxy potassium, sodium hydride, potassium hydride and the like are also preferable. The amount of the base to be used is not particularly limited, but it is 0.1 to 100 mass times based on the bismaleimide compound. It is preferably 0 to 30 times by mass, and more preferably 0 to 10 times by mass.

[Production method of formula (E)] The method for synthesizing a compound of formula (E) is not particularly limited, and examples thereof include the following formula (F) under conditions described in Japanese Patent Application Laid-Open No. 2003-321531 or WO2004012735. The method shown in the reaction of diamine with anhydrous maleic acid derivative.

The amount of the anhydrous maleic acid derivative is preferably 0.01 mol to 1 mol, and more preferably 0.1 mol to 1.0 mol relative to 1 mol of the diamine compound represented by formula (F). . When the diamine (F) is made in an excessive amount, the reaction can be smoothly performed and by-products can be suppressed. This reaction is preferably performed in a solvent. The solvent and reaction conditions are preferably the same as the production conditions of the compound (1). Further, a method in which a diamine represented by the following formula (A) is subjected to metal contact reduction can be mentioned.

This reaction is based on a method for producing the specific diamine represented by the formula (1) by reducing the compound (C1). In the reduction reaction, in consideration of the structure of the compound represented by the above formula (A) and the reactivity of the reduction reaction, it is preferable to perform the reduction reaction in the coexistence of Fe, Sn, Zn, or a salt thereof and a proton.

Among the specific diamines represented by the formula (1) of the present invention, the method for synthesizing diamines in which W ¹ is a carbonyl group is not particularly limited, and examples thereof include nitromaleamidine represented by the formula (A). After an imine compound is reacted with an amine represented by the following formula (B2) to obtain a compound represented by the following formula (G), this is reacted with a dicarboxylic acid represented by the following formula (H) to obtain the following formula A method of reducing the dinitro compound shown in (C2).

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

Further, formula (H) and formula (C2) is preferably in the same line L ¹ in the above formula (B1-1) in the preferred L ^1. The reaction conditions of the compound represented by the formula (B2) and the compound represented by the formula (A) are based on the reaction conditions of the compound represented by the formula (B1) and the compound represented by the formula (A).

By reacting the compound represented by the above formula (G) with the compound where Z is OH in the above formula (H), an inert solvent must be used in the reaction, and a condensing agent must be used in the presence of a base to cause the reaction. A compound represented by the general formula (C2) was obtained. The amount of the rhenium reaction matrix is 0.4 equivalent to 0.8 equivalent of the compound of general formula (H) in which Z is OH, based on 1 equivalent of the compound represented by formula (G).

The condensing agent is not particularly limited as long as it is usually used by the users of the synthesis of amidine. For the compound in which Z is OH in the above formula (H), for example, Xiangshan Test (2-chloro-N-methyl Pyridine), DCC (1,3-dicyclohexylcarbodiimide), WSC (1-ethyl-3- (3-dimethylaminopropyl) -carbodiimide hydrochloride) , CDI (carbonyldiimidazole), dimethylpropynylphosphonium bromide, propargyl triphenylphosphonium bromide, DEPC (diethyl cyanoacetate) and the like, 1 to 4 equivalents.

When a solvent is used, the solvent used is not particularly limited as long as it does not hinder the progress of the reaction, and examples thereof include aromatic hydrocarbons such as benzene, toluene, and stubs, and aliphatic hydrocarbons such as hexane and heptane. Cycloaliphatic hydrocarbons, such as cyclohexane, aromatic halogenated hydrocarbons such as chlorobenzene, dichlorobenzene, dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,1 Aliphatic halogenated hydrocarbons such as 1,1-trichloroethane, trichloroethylene, tetrachloroethylene, diethyl ether, 1,2-dimethoxyethane, tetrahydrofuran, 1,4-dioxane, etc. Ethers, ethyl acetate, ethyl propionate, etc., N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, etc. Amines, triethylamines, tributylamines, amines such as N, N-dimethylaniline, pyridines, pyridines and other pyridines, acetonitrile, and dimethylarsin. These solvents may be used alone or in combination of two or more of them.

Although the addition of a base is not necessary, when a base is used, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide, sodium carbonate, or potassium carbonate can be used with respect to the compound in which Z is OH in the formula (H). Alkali metal carbonates such as sodium bicarbonate, sodium bicarbonate, potassium bicarbonate, etc., triethylamine, tributylamine, N, N-dimethylaniline, pyridine, 4- (dimethylamine Group) 1 to 4 equivalents of organic bases such as pyridine, imidazole, 1,8-diazabicyclo [5,4,0] -7-undecene and the like.

The reaction temperature can be set to any temperature from -60 ° C to the reflux temperature of the reaction mixture. The reaction time varies according to the concentration of the reaction substrate and the reaction temperature, and can generally be arbitrarily set within the range of 5 minutes to 100 hours.

In general, for example, with respect to 1 equivalent of the compound represented by the above formula (G), 0.4 equivalent to 0.8 equivalent of the compound in which Z is OH in the above formula (H) and 1 equivalent to 4 equivalents of WSC (1- Condensing agents such as ethyl-3- (3-dimethylaminopropyl) -carbodiimide hydrochloride), CDI (carbonyldiimidazole), etc., if necessary, 1 to 4 equivalents of potassium carbonate, In the presence of a base such as triethylamine, pyridine, 4- (dimethylamino) pyridine, etc., there is no solvent or use of methylene chloride, chloroform, diethyl ether, tetrahydrofuran, 1,4-dioxane, etc. The solvent is preferably reacted in a range from 0 ° C to the reflux temperature of these solvents for 10 minutes to 24 hours.

In addition, by making a compound in which Z is OH from the above formula (H), a known method described in the literature is used, for example, by reacting it with a chlorinating agent such as thionyl chloride, phosphorus pentachloride, or chloramphonium chloride. Method, method for reacting with organic acid halide such as trimethylacetamyl chloride or isobutyl chloroformate in the presence of a necessary base, or reacting with carbonyldiimidazole or sulfobiimidazole The compound wherein Z is Cl in the above formula (H) and the compound represented by the above formula (G) can be synthesized by a method or the like, and a solvent inert to the reaction is used as necessary, and the reaction is performed in the presence of a base if necessary. It is also possible to synthesize compounds represented by general formula (C2). The amount of the reaction substrate is 0.4 equivalent to 0.8 equivalent of the compound of general formula (H) in which Z is Cl relative to 1 equivalent of the compound represented by formula (G).

When a solvent is used, the solvent used is not particularly limited as long as it does not hinder the progress of the reaction, and examples thereof include aromatic hydrocarbons such as benzene, toluene, and stubble, and aliphatic hydrocarbons such as hexane and heptane. Alicyclic hydrocarbons such as cyclohexane, aromatic halogenated hydrocarbons such as chlorobenzene and dichlorobenzene, dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,1, Fatty halogenated hydrocarbons such as 1-trichloroethane, trichloroethylene, tetrachloroethylene, ethers such as diethyl ether, 1,2-dimethoxyethane, tetrahydrofuran, 1,4-dioxane, etc. Esters, such as ethyl acetate, ethyl propionate, etc., N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, etc. Amines, triethylamine, tributylamine, amines such as N, N-dimethylaniline, pyridines such as pyridine and formidine, acetonitrile and water, etc. These solvents may be used alone or in combination of two or more of them.

The addition of a base is not necessary. When a base is used, for example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide, sodium carbonate, or potassium carbonate may be used with respect to the compound in which Z is Cl in the above formula (H). Alkali metal carbonate, sodium bicarbonate, potassium bicarbonate, etc. alkali metal bicarbonate, triethylamine, tributylamine, N, N-dimethylaniline, pyridine, 4- (dimethylamino group ) 1 to 4 equivalents of organic bases such as pyridine, imidazole, 1,8-diazbicyclo [5,4,0] -7-undecene and the like. The reaction temperature can be set to any temperature from -60 ° C to the reflux temperature of the reaction mixture. The reaction time varies depending on the concentration of the reaction substrate and the reaction temperature, and can usually be arbitrarily set within the range of 5 minutes to 100 hours.

In general, for example, the compound of general formula (H) in which Z is Cl is 0.4 equivalent to 0.8 equivalent with respect to 1 equivalent of the compound represented by the formula (G). Triethylamine, pyridine, 4- (dimethylamino) pyridine, etc. in the presence of a base, without solvent or using dichloromethane, chloroform, diethyl ether, tetrahydrofuran, 1,4-dioxane, acetic acid Ethyl, acetonitrile, and other solvents, and in the range of 0 ° C to the reflux temperature of these solvents, preferably for 10 minutes to 48 hours reaction. The reaction conditions for reducing the dinitro compound represented by the formula (C2) to obtain the diamine represented by the formula (1) are the same as those described above.

The target substance in each stage obtained through the above-mentioned reactions can be purified by distillation, recrystallization, or column chromatography such as silica gel, or the reaction solution can be directly provided to the next stage without purification.

<Polymer> The polymer of the present invention is a polymer obtained by using the above diamine. Specific examples include polyamic acid, polyamidate, polyimide, polyurea, polyamidine, and the like. From the viewpoint of use as a liquid crystal alignment agent, it is selected from the group consisting of the following formula ( 3) At least one of the polyimide precursors of the structural unit shown and the polyimide of the fluorimidate is preferred.

In the above formula (3), X ¹ is a tetravalent organic group derived from a tetracarboxylic acid derivative, Y ¹ is a divalent organic group derived from a diamine containing a structure of formula (1), and R ⁴ is a hydrogen atom or carbon Alkyl groups of 1 to 5. R ^{4 is} preferably a hydrogen atom, a methyl group, or an ethyl group from the viewpoint of being easily imidized by heating.

<Tetracarboxylic dianhydride> X ¹ is a tetravalent organic group derived from a tetracarboxylic acid derivative, and its structure is not particularly limited. In addition, X ¹ in the polyimide precursor may be necessary for the solubility of the polymer in the solvent or the coatability of the liquid crystal alignment agent, the liquid crystal alignment property, the voltage retention rate, and the accumulated charge when the liquid crystal alignment film is formed. The degree of characteristics is appropriately selected. One type may be present in the same polymer, or two or more types may be mixed. If a specific example of X ¹ is specifically exemplified, structures such as the formulae (X-1) to (X-46) disclosed on pages 13 to 14 of International Publication Gazette 2015/119168 can be cited. The following Example illustrates the preferred structure of X ^1, these lines present invention is not defined to a subject.

Among the above-mentioned structures, (A-1) and (A-2) are particularly preferred from the viewpoint of further improving the friction resistance, and (A-4) is especially preferred from the viewpoint of further improving the cumulative charge relaxation speed. From the viewpoint of further improving the alignment of the liquid crystal and the easing rate of the accumulated charge, it is particularly preferable to use (A-15) to (A-17).

<Polymer (other structural unit)> 之 A polyimide precursor containing a structural unit represented by the formula (3) may include a structure selected from the following formula (4) as long as the effect of the present invention is not impaired. At least one of the unit and the polyimide of the sulfonium imide.

In formula (4), X ² is a tetravalent organic group derived from a tetracarboxylic acid derivative, and Y ² is a divalent organic group derived from a diamine that does not include a structure of formula (1) in the main chain direction, and R ¹⁴ Are the same as defined for R ^{4 in} the formula (3), and R ¹⁵ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

Specific examples of X ² include preferable examples, and the same structures as those exemplified as X ¹ in Formula (3) can be mentioned. In addition, Y ² in the polyfluorene imide precursor is a divalent organic group derived from a diamine that does not include a structure of formula (1) in the main chain direction, and the structure is not particularly limited. In addition, Y ² can be appropriately selected according to the necessary degree of characteristics such as the solubility of the polymer in the solvent or the coatability of the liquid crystal alignment agent, the liquid crystal alignment property, the voltage retention rate, and the accumulated charge when the liquid crystal alignment film is formed. The same One type of polymer may be present, or two or more types may be mixed.

If a specific example of Y ² is specifically exemplified, a base represented by the above formula [W ² -1] to the formula [W ² -152] may be mentioned. Examples include the structure of the formula (2) disclosed on page 4 of International Publication Gazette 2015/119168, and the formulas (Y-1) to (Y-97), ( Structures of Y-101) to (Y-118); Divalent organic groups obtained by removing two amine groups in formula (2) disclosed on page 6 of International Publication 2013/008906; from International Publication 2015/122413 Formula (1) disclosed on page 8 is a divalent organic group obtained by removing two amine groups; Structure of formula (3) disclosed on page 8 of International Publication Gazette 2015/060360; Japanese Patent Publication 2012-173514 The divalent organic group obtained by removing two amine groups in the formula (1) described on page 8; removing two amine groups from the formulas (A) to (F) disclosed in page 9 of International Publication 2010/050523 Into bivalent organic groups.

As preferred structure ² of Y, may be configured to include the following formula (11) of.

In formula (11), R ³² is a single bond or a divalent organic group, and a single bond is preferred. R ³³ is a structure shown by-(CH ₂ ) _r- . r is an integer from 2 to 10, preferably from 3 to 7. In addition, any of -CH ₂ -may be substituted with an ether, ester, amidine, urea, or urethane bond under the condition that they are not adjacent to each other. R ³⁴ is a single bond or a divalent organic group. Any hydrogen atom on the benzene ring may be substituted by a monovalent organic group, but a fluorine atom or a methyl group is preferred. Specific examples of the structure represented by the formula (11) include the following structures, but they are not limited to these structures.

In the case where the polyimide precursor containing the structural unit shown in formula (3) also contains the structural unit shown in formula (4), in order to quickly alleviate the accumulated charge and control the deviation between the rubbing direction and the liquid crystal alignment direction From the viewpoint, the structural unit shown in formula (3) is preferably 1 mol% to 80 mol%, and more preferably 5 mol% to 60 mol relative to the total of formula (3) and formula (4). %, Particularly preferably 10 mol% to 40 mol%. Further, as a preferred structure of Y ² include such as those having an amine group selected from the group consisting of, an alkylene group, a nitrogen-containing heterocyclic ring and at least one of the groups is configured.

As the structure of such Y ² , it is necessary to have at least one structure selected from the group consisting of an amine group, an imine group, and a nitrogen-containing heterocyclic ring, or a structure selected from the group consisting of a nitrogen atom substituted with a heat-releasing group The structure of at least one of an amine group, an imino group, and a nitrogen-containing heterocyclic ring is not particularly limited. If specific examples are specifically exemplified, there may be at least 1 selected from the group consisting of an amine group, an imine group, and a nitrogen-containing heterocyclic ring represented by the following formulae (YD-1) to (YD-5). This structure is a bivalent organic group.

In the formula (YD-1), A ₁ is a nitrogen atom-containing heterocyclic ring having 3 to 15 carbon atoms, and Z ₁ is a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent. In the formula (YD-2), V ₁ is a hydrocarbon group having 1 to 10 carbon atoms, and A ₂ is a monovalent organic group having 3 to 15 carbon atoms having a nitrogen atom-containing heterocyclic ring, or an aliphatic group having 1 to 6 carbon atoms. Disubstituted amine group. In the formula (YD-3), V ₂ is a divalent organic group having 6 to 15 carbon atoms and having 1 to 2 benzene rings, V ₃ is an alkylene group or a biphenylene group having 2 to 5 carbon atoms, and Z ₂ Is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a benzene ring, or a thermally detachable group, and a is an integer of 0 to 1; In the formula (YD-4), A ₃ is a nitrogen atom-containing heterocyclic ring having 3 to 15 carbon atoms. In the formula (YD-5), A ₄ is a nitrogen atom-containing heterocyclic ring having 3 to 15 carbon atoms, and V ₅ is an alkylene having 2 to 5 carbon atoms.

Nitrogen-containing heteroatoms having carbon numbers of 3 to 15 as A ₁ , A ₂ , A ₃ , and A ₄ of the formulae (YD-1), (YD-2), (YD-4), and (YD-5) The ring is not particularly limited as long as it has a known structure. Among them, for example, pyrrolidine, pyrrole, imidazole, pyrazole, oxazole, thiazole, piperidine, piperazine, pyridine, pyrazine, indole, benzimidazole, quinoline, isoquinoline, piperazine, Piperidine, indole, benzimidazole, imidazole, carbazole, and pyridine are preferred. In addition, the thermally detachable group may be a substituent that is not detached at room temperature, and is detached and replaced with a hydrogen atom only when the alignment film is fired. Specific examples include tert-butoxycarbonyl and 9- Fluorenylmethoxycarbonyl.

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

In the formulae (YD-14) and (YD-21), j is an integer of 0 to 3.

In the formulae (YD-24), (YD-25), (YD-28), and (YD-29), j is an integer of 0 to 3.

(In the formula (YD-50), m and n are each an integer of 1 to 11, and m + n is an integer of 2 to 12.)

<Manufacturing method of polyamic acid> The poly (amino acid) of the poly (imine) precursor used in the present invention can be synthesized by the method shown below. Specifically, by reacting tetracarboxylic dianhydride and diamine in the presence of an organic solvent at a temperature of -20 ° C to 150 ° C, preferably 0 ° C to 70 ° C, the reaction is preferably performed for 30 minutes to 24 hours. 1 hour to 12 hours to synthesize. The solubility of the organic solvent used in the above reaction from monomers and polymers is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, γ-butyrolactone, etc. Etc. may be used singly or in combination of two or more.

The polymer concentration is preferably from 1% by mass to 30% by mass, and more preferably from 5% by mass to 20% by mass, from the viewpoint that it is difficult to cause precipitation of the polymer and it is easy to obtain a high molecular weight substance. The polyamic acid obtained by the above-mentioned operation can precipitate the polymer and recover it by stirring the reaction solution and injecting it into a poor solvent at the same time. Furthermore, after carrying out precipitation several times, washing with a poor solvent, and drying under normal temperature or heating, a purified polyamic acid powder can be obtained. The lean solvent is not particularly limited, and examples thereof include water, methanol, ethanol, 2-propanol, hexane, butyl cellosolve, acetone, toluene, and the like, and water, methanol, ethanol, and 2-propanol are preferred.

<The production method of polyimide> The polyimide used in the present invention can be produced by imidizing the aforementioned polyamidic acid. When a polyfluorene imine is produced from a polyamic acid, it is relatively easy to add a catalyst to the chemical polyfluorine imidization obtained by reacting the diamine component with a tetracarboxylic dianhydride. Chemical fluorene imidization is preferred because fluorene imidization is performed at a relatively low temperature, and the molecular weight of the polymer is not easily reduced during fluorene imidization, so it is preferred. Chemical fluorene imidization can be carried out by stirring a polymer to be fluorinated in fluorene in an organic solvent in the presence of a basic catalyst and an acid anhydride. As the organic solvent, a solvent used in the aforementioned polymerization reaction can be used. Examples of the basic catalyst include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among them, pyridine is preferable because it has a moderate basicity for the reaction to proceed. Examples of the acid anhydride include anhydrous acetic acid, anhydrous trimellitic acid, and anhydrous pyromellitic acid. Among them, when anhydrous acetic acid is used, purification after the completion of the reaction is facilitated, so it is preferable.

The temperature at which the amidine imidization reaction is performed is -20 ° C to 140 ° C, preferably 0 ° C to 100 ° C. The reaction time can be carried out within 1 hour to 100 hours. The amount of alkaline catalyst is 0.5 to 30 times moles of polyamino acid group, preferably 2 to 20 times moles of polyamino acid group, and the amount of acid anhydride is 1 times mole of polyamino acid group. ~ 50 times mole, preferably 3 times ~ 30 times mole. The hydrazone imidization rate of the obtained polymer can be controlled by adjusting the amount of catalyst, temperature, and reaction time. Since the added catalyst and the like remain in the solution after the polyimidation reaction of the polyimide, the obtained imidized polymer is recovered by the method described below and redissolved with an organic solvent. It is better to use the liquid crystal alignment agent of the invention.

The polyimide solution obtained by the above operation can precipitate the polymer by well stirring and simultaneously injecting a poor solvent. After carrying out precipitation several times and washing with a poor solvent, drying at room temperature or heating can obtain a purified polymer powder. The lean solvent is not particularly limited, and examples thereof include methanol, 2-propanol, acetone, hexane, butylcythrene, heptane, methyl ethyl ketone, methyl isobutyl ketone, ethanol, toluene, Benzene and the like are preferably methanol, ethanol, 2-propanol, acetone and the like.

<Production of polyimide precursor-polyamidate> The polyamidate of the polyimide precursor used in the present invention can be expressed by the following (1), (2), or (3) ).

(1) Case of production from polyamic acid The polyfluorinated polyamic acid ester is produced by esterifying the polyfluorinated acid prepared as described above. Specifically, the polyamic acid and the 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 It is produced by reacting for 1 to 4 hours. The esterification agent is preferably one which can be easily removed by purification, and examples thereof include N, N-dimethylformamide dimethyl acetal and N, N-dimethylformamide diethyl acetal. Aldehyde, N, N-dimethylformamide dipropyl acetal, N, N-dimethylformamide dineopentylbutyl acetal, N, N-dimethylformamide di-t -Butyl acetal, 1-methyl-3-p-tolyl triazene, 1-ethyl-3-p-tolyl triazene, 1-propyl-3-p-tolyl triazene , 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholine and the like. The addition amount of the esterifying agent is 1 mol relative to the repeating unit of the polyamidic acid, and preferably 2 mol equivalent to 6 mol equivalent.

Examples of the organic solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N, N-dimethylformamide, N, N-dimethylacetamidine, dimethylarsine or 1,3-dimethyl-imidazolinone. When the solvent solubility of the polyimide precursor is high, for example, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or the like may be used. Solvents represented by the formulas [D-1] to [D-3]. These solvents can be used alone or in combination. In addition, even if it is a solvent that does not dissolve the polyfluorene imide precursor, it can be mixed with the aforementioned solvent and used in a range that does not precipitate the generated polyfluorene imide precursor. In addition, since the water in the solvent may hinder the polymerization reaction and cause hydrolysis of the produced polyimide precursor, the solvent is preferably one that is dehydrated and dried.

The solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone, or γ-butyrolactone from the viewpoint of the solubility of the polymer. Use 1 type or mix 2 or more types. The concentration at the time of production is from the viewpoint that it is not easy to cause polymer precipitation and it is easy to obtain a high molecular weight substance, preferably 1% to 30% by mass, and more preferably 5% to 20% by mass.

(2) Production by reaction of tetracarboxylic acid diester dichloride and diamine Polyfluorene esters can be produced from tetracarboxylic acid diester dichloride and diamine. Specifically, the tetracarboxylic acid diester dichloride and diamine can be reacted in the presence of a base and an organic solvent at -20 ° C to 150 ° C, preferably at 0 ° C to 50 ° C, for 30 minutes to It is produced in 24 hours, preferably 1 hour to 4 hours. As the base, for example, pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used. In order to make the reaction proceed smoothly, pyridine is preferred. The addition amount of the alkali is preferably from 2 to 4 times the mole of the tetracarboxylic acid diester dichloride from the viewpoint of the amount that can be easily removed and high-molecular-weight substances are easily obtained.

From the viewpoint of the solubility of the monomers and polymers, the solvent used in the above reaction is preferably N-methyl-2-pyrrolidone or γ-butyrolactone. These may be used alone or in combination. Use by mixing 2 or more types. The polymer concentration at the time of production is preferably from 1% by mass to 30% by mass, and more preferably from 5% by mass to 20% by mass, from the viewpoint that it is not easy to cause polymer precipitation and it is easy to obtain a high molecular weight substance. In addition, in order to prevent the hydrolysis of the tetracarboxylic acid diester dichloride, the solvent used in the production of the polyamidate is preferably dehydrated as much as possible, and it is better to prevent outside air from being mixed in a nitrogen environment.

(3) Production from a tetracarboxylic acid diester and a diamine Polyfluorene esters can be produced by polycondensing a tetracarboxylic acid diester and a diamine. Specifically, a tetracarboxylic diester and a diamine can be reacted in the presence of a condensing agent, a base, and an organic solvent at 0 ° C to 150 ° C, preferably 0 ° C to 100 ° C, for 30 minutes to 24 minutes. It is preferably produced by reacting for 3 hours to 15 hours.

As the condensing agent, triphenylphosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, N can be used. , N'-carbonyldiimidazole, dimethoxy-1,3,5-triazinylmethylmorpholinium, O- (benzotriazol-1-yl) -N, N, N ', N' -Tetramethylurenium tetrafluoroborate, O- (benzotriazol-1-yl) -N, N, N ', N'-tetramethylurenium hexafluorophosphate, (2,3- Dihydro-2-thio-3-benzoxazolyl) phosphonic acid diphenyl and the like. Relative to the tetracarboxylic acid diester, the addition amount of the condensing agent is preferably 2 times to 3 times mole.

As the base, tertiary amines such as pyridine and triethylamine can be used. The addition amount of the alkali is preferably from 2 to 4 times the mole compared to the diamine component from the viewpoint of easy removal and easy access to high molecular weight substances. In the above reaction, the reaction can be efficiently performed by adding a Lewis acid as an additive. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferred. The addition amount of the Lewis acid is preferably 0 to 1.0 times mole compared to the diamine component. Since a high molecular weight polyamidate can be obtained, among the above-mentioned three polyamidate production methods, the above-mentioned (1) or (2) production method is particularly preferred. The polymer solution obtained by the above operation can be precipitated into the polymer by being well stirred and simultaneously injected into a poor solvent. After carrying out precipitation several times, washing with a poor solvent, and then drying at room temperature or heating, a purified polyurethane powder can be obtained. The lean solvent is not particularly limited, and examples thereof include water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.

In the production of the polymer of the present invention, in the above-mentioned production method, a diamine represented by the formula (1) may be used as the diamine. In the case where the polymer contained in the liquid crystal alignment agent of the present invention, that is, the polyimide precursor or the molecular weight of the polyimide is obtained from a liquid crystal alignment agent containing the polymer, the coating film (liquid crystal alignment film) is considered. The weight average molecular weight measured by GPC (Gel Permeation Chromatography) method, the workability during coating film formation, and the uniformity of the coating film are preferably 2,000 to 500,000, more preferably 5,000 to 300,000, and 10,000 to 100,000 is more preferable.

<Liquid crystal alignment agent> 之 The liquid crystal alignment agent of the present invention contains a polymer (specific polymer) obtained from a diamine having a structure represented by the formula (1), but it may be within the range of effects described in the present invention. Contains two or more specific polymers with different structures. Further, in addition to the specific polymer, other polymers, that is, polymers which do not have a divalent group represented by the formula (1) may be contained. Examples of other polymers include polyamic acid, polyimide, polyamidate, polyester, polyamidine, polyurea, polyorganosiloxane, cellulose derivative, and polycondensation. Aldehydes, polystyrene or derivatives thereof, poly (styrene-phenylmaleimide) derivatives, poly (meth) acrylates, and the like. When the liquid crystal alignment agent of the present invention contains other polymers, the proportion of the specific polymer with respect to the entire polymer component is preferably 5% by mass or more. Examples thereof include 5% to 95% by mass.

The liquid crystal alignment agent is generally used in the form of a coating liquid from the viewpoint of forming a uniform thin film for a user who manufactures a liquid crystal alignment film. The liquid crystal alignment agent of the present invention is preferably a coating liquid containing the aforementioned polymer component and an organic solvent in which the polymer component is dissolved. At this time, the concentration of the polymer in the liquid crystal alignment agent can be appropriately changed according to the setting of the thickness of the coating film to be formed. From the viewpoint of forming a uniform and defect-free coating film, it is preferably 1% by mass or more, and from the viewpoint of storage stability of the solution, 10% by mass or less is preferable. The concentration of the particularly good polymer is 2% to 8% by mass.

The organic solvent contained in the liquid crystal alignment agent is not particularly limited as long as it dissolves the polymer component uniformly. Specific examples thereof include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, and N-ethyl-2 -Pyrrolidone, dimethylarsine, γ-butyrolactone, 1,3-dimethyl-imidazolinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, and the like. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ-butyrolactone is preferably used.

In addition, the organic solvent contained in the liquid crystal alignment agent is generally a mixed solvent in which a solvent as described above and a solvent that improves the coatability or the surface smoothness of the coating film when the liquid crystal alignment agent is applied are used. The present invention The liquid crystal alignment agent is also suitable for using such a mixed solvent. The following are specific examples of organic solvents used in combination, but are not limited by these examples. Examples include ethanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2- Methyl-1-butanol, isoamyl 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 -Propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 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-ethyl Oxybutyl acetate, 1-methyl Ethyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethyl carbonate, 2- (methoxymethoxy) ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisopentyl ether, ethylene glycol monohexyl ether, 2- (hexyloxy) ethanol, furfuryl alcohol, diethylene glycol Ethylene 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 monobutyl ether acetate, ethylene glycol Alcohol monoacetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2- (2-ethoxyethoxy) Ethyl acetate, diethylene glycol acetate, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, ethyl lactate, methyl acetate, acetic acid Ethyl acetate, n-butyl acetate, propylene glycol monoethyl ether, pyruvate Methyl ester, ethyl pyruvate, methyl 3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3- Methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate Esters, solvents represented by the following formulas [D-1] to [D-3], and the like.

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 in formula [D-3], D ³ Represents an alkyl group having 1 to 4 carbon atoms.

Among them, 1-hexanol, cyclohexanol, 1,2-ethanediol, 1,2-propylene glycol, propylene glycol monobutyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl Phenyl-2-pentanone, ethylene glycol monobutyl ether or dipropylene glycol dimethyl ether is preferred.

The type and content of such a solvent can be appropriately selected according to the coating device, coating conditions, and coating environment of the liquid crystal alignment agent.

The liquid crystal alignment agent of the present invention may further contain components other than the polymer component and the organic solvent, as long as the effect of the present invention is not impaired. Examples of such additional components include adhesion promoters for improving the adhesion between the liquid crystal alignment film and the substrate, adhesion promoters for improving the adhesion between the liquid crystal alignment film and the sealing material, and crosslinking agents for increasing the strength of the liquid crystal alignment film. 2. Adjust the dielectric constant of the liquid crystal alignment film or the dielectric or conductive material for resistance. As specific examples of these additional components, such as those disclosed in publicly known literatures on liquid crystal alignment agents, if one of them is specifically exemplified, for example, International Publication No. 2015/060357, page 53 [0105] ~ 55 pages [0116] Ingredients disclosed.

<Liquid Crystal Alignment Film> The liquid crystal alignment film of the present invention is obtained from the aforementioned liquid crystal alignment agent. If an example of a method for obtaining a liquid crystal alignment film from a liquid crystal alignment agent is given, for example, a liquid crystal alignment agent in the form of a coating liquid is applied to a substrate, and a film obtained by drying and firing is rubbed or lighted. Alignment treatment method. The substrate for applying the liquid crystal alignment agent is not particularly limited as long as it is a substrate having high transparency. In addition to a glass substrate, a silicon nitride substrate, a plastic substrate such as an acrylic substrate or a polycarbonate substrate may be used. In this case, from the viewpoint of simplification of the manufacturing process, it is preferable to use a substrate on which an ITO electrode or the like for liquid crystal driving has been formed. Moreover, in a reflective liquid crystal display element, if only an opaque object such as a silicon wafer can be used on a single-sided substrate, a material such as aluminum that reflects light can also be used as the electrode.

The coating method of the liquid crystal alignment agent is not particularly limited, and it is generally screen printing, lithography, flexographic printing, inkjet method and the like in the industry. As other coating methods, there are a dipping method, a roll coating method, a slit coating method, a spin coating method, a spray method, and the like, and these can be used depending on the purpose. After the liquid crystal alignment agent is coated on the substrate, the solvent is evaporated and fired by heating means such as a hot plate, a thermal cycle oven, and an IR (infrared) oven. The steps of drying and firing after applying the liquid crystal alignment agent can be selected at any temperature and time. Generally, in order to sufficiently remove the contained solvent, conditions such as firing at 50 ° C to 120 ° C for 1 minute to 10 minutes, and then firing at 150 ° C to 300 ° C for 5 minutes to 120 minutes can be mentioned. The thickness of the liquid crystal alignment film after firing is not particularly limited. If the thickness is too thin, the reliability of the liquid crystal display element may be reduced. Therefore, the thickness is preferably 5 nm to 300 nm, and more preferably 10 nm to 200 nm. The liquid crystal alignment film of the present invention is a liquid crystal alignment film suitable for a liquid crystal display element of a transverse electric field method such as an IPS method or an FFS method, and is particularly a liquid crystal alignment film useful as a liquid crystal display device of an FFS method.

<Liquid crystal display element> The liquid crystal display element of the present invention is obtained by obtaining a substrate with a liquid crystal alignment film from the above-mentioned liquid crystal alignment agent, and manufacturing a liquid crystal cell by a known method, and using the liquid crystal cell as an element. As an example of a method for manufacturing a liquid crystal cell, a liquid crystal display element having a passive array structure will be described as an example. Furthermore, it may be a liquid crystal display element having an active array structure in which a switching element such as a TFT (Thin Film Transistor) is provided in each pixel portion constituting a portrait display. Specifically, a transparent glass substrate is prepared, a common electrode is provided on one substrate, and a segment electrode is provided on the other substrate. These electrode systems can be made of, for example, ITO electrodes, and the patterns can be converted to display a desired image. Next, an insulating film is provided on each substrate so as to cover the common electrode and the segment electrode. The insulating film is, for example, a film composed of SiO ₂ -TiO ₂ formed by a sol-gel method. Next, a liquid crystal alignment film is formed on each substrate under the aforementioned conditions.

Next, a UV-curable sealing material is placed in a predetermined place on one of the two substrates on which the liquid crystal alignment film has been formed, and then the liquid crystal is placed in a predetermined number of places on the liquid crystal alignment film surface. After the liquid crystal alignment film is pressed against the substrate on the other side, the liquid crystal is pressed toward the front of the liquid crystal alignment film and diffused, and then the sealing material is hardened by irradiating the substrate with ultraviolet rays to obtain a liquid crystal cell. In addition, as a step after the liquid crystal alignment film is formed on the substrate, when a sealing material is arranged at a predetermined place on one substrate, an opening portion capable of filling liquid crystal from the outside is provided in advance, and the substrate is bonded without the liquid crystal. A liquid crystal material is injected into the liquid crystal cell at an opening portion on the sealing material, and then the opening portion is sealed with an adhesive to obtain a liquid crystal cell. The injection of the liquid crystal material may be a vacuum injection method or a method using a capillary phenomenon in the atmosphere.

In any of the above methods, in order to ensure a space for filling the liquid crystal material in the liquid crystal cell, a columnar protrusion is provided on one substrate, a spacer is scattered on the other substrate, or a spacer is mixed in the sealing material. , Or a combination of these.

Examples of the liquid crystal material include nematic liquid crystals and smectic liquid crystals. Among them, nematic liquid crystals are preferred, and either a positive liquid crystal material or a negative liquid crystal material can be used. Next, set the polarizer. Specifically, it is preferable to attach a pair of polarizing plates on the surface opposite to the liquid crystal layer of the two substrates.

In addition, as long as the liquid crystal alignment film and liquid crystal display element of the present invention are liquid crystal alignment agents of the present invention, they are not limited to those described above, and may be made by other known methods. The steps until the liquid crystal display element is obtained from the liquid crystal alignment agent are disclosed in, for example, Japanese Patent Application Laid-Open No. 2015-135393 (Japanese Patent Laid-Open Publication), pages 17 [0074] to 19 [0081], etc. In the literature. [Example]

The following examples illustrate the invention in more detail, but the invention is not limited by these.略 The abbreviations of the compounds used in the examples and comparative examples, and the methods of property evaluation are as follows. NMP: N-methyl-2-pyrrolidone BCS: Butyl cellosolve GBL: γ-butyrolactone NMP: N-methyl-2-pyrrolidone DA-1-1: The following formula DA-1-1 Compound DA-2 shown: Compound DA-3 represented by the following formula DA-2: Compound CA-1 represented by the following formula DA-3: Compound CA-2 represented by the following formula CA-1: Compound represented by the following formula CA-2

Synthesis of Example 1A (DA-1-1)

15.00 g (68.8 mmol) of N- (4-nitrophenyl) maleimide and 300 g of tetrahydrofuran (hereinafter, THF) were added to the flask, followed by ice-cooling. To this mixture was added 3.37 g (33.0 mmol) of N, N'-dimethyl-1,3-propanediamine. After that, after slowly returning to room temperature, it was stirred at room temperature for 1 day. After confirming the completion of the reaction, 200 g of ethyl acetate was added to the reaction mixture, followed by stirring. The crystals obtained by filtration were dried at 50 ° C to obtain 11.1 g of the intended nitro body intermediate (DA-1-1-1) (yield 62%). 1H-NMR (D6-DMSO, δppm): 8.37 (d, 4H), 7.62 (d, 4H), 4.15-4.21 (m, 1H), 2.93-3.03 (m, 2H), 2.80-2.89 (m, 2H ), 2.53-2.70 (m, 4H), 2.32 (s, 6H), 1.57-1.67 (m, 2H)

In a nitrogen-substituted flask, put 11.1 g (20.6 mmol) of DA-1-1-1, 1 g of 5% Pd-C (STD type, wet product, manufactured by NE Chemcat (stock)), and N, N-dimethylformate. After 300 g of methylformamide (hereinafter, DMF), the flask was replaced with hydrogen. This reaction mixture was stirred at room temperature for 3 days under hydrogen pressure and normal pressure. After confirming the completion of the reaction, Pd-C was removed from the reaction mixture by filtration, and the filtrate was distilled off under reduced pressure. To the obtained residue was added chloroform and stirred. The insoluble matter was removed by filtration, and the obtained filtrate was distilled off under reduced pressure, and the target DA-1-1 was obtained as a viscous liquid 8.93 g (yield 90%). 1H-NMR (D6-DMSO, δppm): 6.79 (d, 4H), 6.55 (d, 4H), 5.274 (brs, 4H), 3.99-4.04 (m, 2H), 2.79-2.89 (m, 2H), 2.44-2.71 (m, 6H), 3.23 (s, 6H), 1.51-1.61 (m, 2H)

Synthesis of Example 2A (DA-1-2)

0.1246 g (0.662 mmol) of N- (4-aminophenyl) maleimide and 3 g of THF were added to the flask, and the mixture was ice-cooled. To this mixture was added 0.0285 g (0.331 mmol) of piperazine. After that, after slowly returning to room temperature, it was stirred at room temperature for 3 days. After confirming the completion of the reaction, the precipitated crystals were filtered, and the crystals were washed with diisopropyl ether (hereinafter, IPA). After the obtained crystals were dried at 50 ° C, 0.067 g of the intended DA-1-2 was obtained (yield: 47%). 1H-NMR (D6-DMSO, δppm): 6.82 (d, 4H), 6.59 (d, 4H), 5.30 (brs, 4H), 3.92-3.98 (m, 2H), 2.70-2.95 (m, 8H), 2.40-55 (m, 2H)

Synthesis of Example 3A (DA-1-3)

After adding 2.90 g (15.4 mmol) of N- (4-aminophenyl) maleimide and 30 g of tetrahydrofuran (hereinafter, THF) to the flask, the mixture was ice-cooled. To this mixture, 1.00 g (7.34 mmol) of 4- (aminomethyl) benzylamine was added. After that, after slowly returning to room temperature, it was stirred at room temperature for 3 hours. After confirming the completion of the reaction, the reaction mixture was cooled again and the precipitated crystals were filtered. The obtained crystals were dried at 45 ° C under reduced pressure, and the target compound (DA-1-3) was obtained as 1.59 g of yellow crystals (yield: 42%). 1H-NMR (D6-DMSO, δppm): 7.32 (s, 4H), 6.84 (d, 4H), 6.59 (d, 4H), 5.31 (brs, 4H), 3.82-3.95 (m, 4H), 3.74- 3.82 (m, 2H), 2.91-3.01 (m, 2H), 2.94 (brs, 2H), 2.53-2.56 (m, 1H), 2.48-2.51 (m, 1H)

[Viscosity measurement] The viscosity of the polyfluorene acid solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample volume of 1.1 mL and a tapered rotor TE-1 (1 ° 34 ', R24). measuring.

[Example 1] (1) DA-1-1 (3.34 g, 7 mmol) was added to a 50-ml four-neck burner with a stirring device and a nitrogen-containing introduction tube, and then 31.5 g of NMP was added. Nitrogen was transported while stirring to dissolve. CA-1 (1.43 g, 6.58 mmol) was added to this diamine solution while stirring, and 3.5 g of NMP was added, and then a polyamic acid solution (PAA-1) was obtained by stirring at 50 ° C. for 12 hours. The viscosity of this polyamic acid solution at 25 ° C was 270 mPa · s.

[Example 2] (1) DA-1-1 (3.34 g, 7 mmol) was added to a 50-ml four-necked flask equipped with a stirring device and a nitrogen-containing introduction tube, and then 31.1 g of NMP was added. Nitrogen was transported and dissolved while being stirred. CA-1 (0.61g, 2.8mmol) and CA-2 (0.75g, 3.9mmol) were added while stirring this diamine solution. After adding 3.5g of NMP, the mixture was stirred at 50 ° C for 12 hours to obtain polymerization. Amino acid solution (PAA-2). The viscosity of this polyamic acid solution at 25 ° C was 280 mPa · s.

[Comparative Example 1] DA-2 (5.73 g, 20 mmol) was added to a 100 ml four-necked flask equipped with a stirring device and a nitrogen-containing introduction tube, and 65.1 g of NMP was added. Nitrogen was transported and dissolved while being stirred. CA-1 (4.14 g, 19 mmol) was added to this diamine solution while stirring, and 7.2 g of NMP was added, and then a polyamic acid solution (PAA-3) was obtained by stirring at room temperature for 18 hours. The viscosity of the polyamic acid solution at 25 ° C was 500 mPa · s.

[Comparative Example 2] DA After adding DA-3 (1.98 g, 10 mmol) to a 50-ml four-necked flask equipped with a stirring device and a nitrogen-containing introduction tube, 26.0 g of NMP was added, and nitrogen was stirred while being dissolved. CA-1 (0.87g, 4.0mmol) and CA-2 (1.08g, 5.5mmol) were added to this diamine solution while stirring, and 2.9g of NMP was added, and then polymerization was performed by stirring at 50 ° C for 12 hours. Amino acid solution (PAA-4). This polyamic acid solution has a viscosity of 300 mPa · s at 25 ° C.

[Example 3] Separate and take out 7.5 g of the polyamic acid solution (PAA-1) obtained in Example 1, and while stirring, add 5.6 g of NMP, 6.0 g of BCS, and 3-aminopropyltriethoxysilane 1 A 0.9% by weight NMP solution was further stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (Q-1).

[Example 4] Separate and take out 7.5 g of the polyamic acid solution (PAA-2) obtained in Example 2, and while stirring, add 5.6 g of NMP, 6.0 g of BCS, and 3-aminopropyltriethoxysilane 1 A 0.9% by weight NMP solution was further stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (Q-2).

[Comparative Example 3] Separately obtain 7.5 g of the polyamic acid solution (PAA-3) obtained in Comparative Example 1, and while stirring, add 5.6 g of NMP, 6.0 g of BCS, and 3-aminopropyltriethoxysilane 1 A 0.9% by weight NMP solution was further stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (Q-3).

[Comparative Example 4] Separate and take out 7.5 g of the polyamic acid solution (PAA-4) obtained in Comparative Example 2, and while stirring, add 5.6 g of NMP, 6.0 g of BCS, and 3-aminopropyltriethoxysilane 1 A 0.9% by weight NMP solution was further stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (Q-4).

[Production of liquid crystal cell for ion density measurement] 后 After filtering the liquid crystal alignment agent with a 1.0 μm filter, spin-coat it on a substrate with electrodes (30 mm horizontal × 40 mm vertical and 1.1 mm thick glass) Substrate. The electrode is a rectangular ITO electrode with a width of 10mm × length of 40mm and a thickness of 35nm. After drying on a hot plate at 50 ° C for 5 minutes, firing was performed in an IR oven at 230 ° C for 20 minutes to form a coating film with a thickness of 100 nm to obtain a substrate with a liquid crystal alignment film. This liquid crystal alignment film was rubbed with rubbing cloth (YA-20R manufactured by Yoshikawa Chemical Co., Ltd.) (roller diameter: 120 mm, number of roll rotations: 1000 rpm, moving speed: 20 mm / sec, push-in length: 0.4 mm), and then implemented in pure water. The substrate was cleaned by ultrasonic irradiation for 1 minute, and water droplets were removed by blowing air, and then dried at 80 ° C. for 15 minutes to obtain a substrate with a liquid crystal alignment film.

Prepare the above two substrates with liquid crystal alignment film. After spreading a 4 μm spacer on one of the liquid crystal alignment film surfaces, print a sealing material from it, and place the other substrate in the opposite direction with the rubbing direction and the film surface. After bonding to each other, the sealing material is hardened to produce an empty unit. MLC-3019 (manufactured by Merck) was injected into the empty cell by a reduced pressure injection method, and the injection port was closed to obtain a liquid crystal cell. Thereafter, the obtained liquid crystal cell was heated at 120 ° C. for 1 hour and left at 23 ° C. for a while to obtain a liquid crystal cell for ion density measurement.

[Ion density measurement] (1) The ion density was measured on the liquid crystal cell produced by the method described in [Preparation of the liquid crystal cell for ion density measurement]. Ion density measurement measures the ion density when a triangular wave with a voltage of ± 10 V and a frequency of 0.01 Hz is applied to the liquid crystal cell. The measurement temperature was performed at 60 ° C. The measuring device was a 6256 type liquid crystal physical property evaluation device manufactured by Toyo Technology Co., Ltd. The measurement of the ion density is performed after the unit is manufactured and after the unit is aged for 120 hours under the conditions of high temperature and high humidity of 60 ° C and 90%.

[Production of liquid crystal display element] First prepare a substrate with electrodes. The substrate is a glass substrate having a size of 30 mm × 35 mm and a thickness of 0.7 mm. An IZO electrode having a solid pattern is formed on the substrate as a first layer. A SiN (silicon nitride) film formed by a CVD method is formed on the counter electrode of the first layer as the second layer. The film thickness of the SiN film of the second layer is 500 nm, and its function is to serve as an interlayer insulating film. A comb-shaped pixel electrode formed by patterning an IZO film is arranged on the second layer of the SiN film, and two pixels of the first pixel and the second pixel are formed as the third layer. The size of each pixel is about 10 mm in length and about 5 mm in width. At this time, the counter electrode of the first layer and the pixel electrode of the third layer are electrically insulated by the action of the SiN film of the second layer.

The pixel electrode of the third layer has a comb-tooth shape formed by a plurality of electrode elements arranged in a central portion and bent into an L-shape as in the figure described in Japanese Patent Application Laid-Open No. 2014-77845. The width in the transverse direction of each electrode element is 3 μm, and the interval between the electrode elements is 6 μm. The pixel electrode forming each pixel is formed by a plurality of L-shaped electrode elements bent in the central portion of the plurality of pixels. Therefore, the shape of each pixel is not rectangular, but is similar to that of the electrode element. L-shape of bold type. In addition, each pixel is divided into an upper part and a lower part with a central curved portion as a border, and has a first region on the upper side and a second region on the lower side.

When the first region and the second region of each pixel are compared, it is found that the formation directions of the electrode elements constituting the pixel electrodes are different. That is, when the rubbing direction of the liquid crystal alignment film described later is used as a reference, the electrode element of the pixel electrode in the first region of the pixel is formed at an angle (clockwise) of + 10 °, and in the second region of the pixel The electrode element of the pixel electrode is formed so as to have an angle (clockwise) of -10 °. That is, in the first region and the second region of each pixel, the directions of the rotation operation (in-plane switching) of the liquid crystal in the substrate plane induced by applying a voltage between the pixel electrode and the counter electrode are mutually It is constituted in the opposite direction.

Secondly, after the liquid crystal alignment agent obtained by filtering using a 1.0 μm filter, the prepared substrates with electrodes and the opposite substrates were formed with ITO films and column spacers with a height of 4 μm. The glass substrate was spin-coated. Next, after drying on a hot plate at 80 ° C. for 5 minutes, firing at 230 ° C. for 20 minutes, a polyimide film was obtained on each substrate as a coating film having a thickness of 60 nm. This polyimide film was rubbed with a rubbing cloth in a predetermined rubbing direction (roller diameter 120 mm, rotation number 500 rpm, moving speed 30 mm / sec, and feed amount 0.3 mm). Minute ultrasound was irradiated and dried at 80 ° C for 10 minutes.

Thereafter, the two types of substrates with the liquid crystal alignment film described above were combined so that their rubbing directions became anti-parallel, leaving the liquid crystal injection port and sealing the surroundings, and producing empty cells with a cell gap of 3.8 μm. . After the liquid crystal (MLC-3019, manufactured by Merck) is vacuum-injected into the empty cell at normal temperature, the injection port is sealed to form an anti-parallel liquid crystal cell. The obtained liquid crystal cell constitutes an FFS mode liquid crystal display element. Thereafter, the obtained liquid crystal cell was heated at 120 ° C. for 1 hour, left for a while, and then used for each evaluation.

[Stability evaluation 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, a state in which the pixel electrode and the counter electrode of the liquid crystal cell became short-circuited was made, and left at room temperature for one day. After being placed, the liquid crystal cell is placed between two polarizing plates in which polarizing axes are arranged orthogonally, and the backlight is lit in advance in a state where no voltage is applied, and adjusted so that the brightness of penetrating light is minimized. Configuration angle of the liquid crystal cell. Thereafter, the rotation angle when the liquid crystal cell is rotated from the angle at which the second region of the first pixel becomes the darkest to the angle at which the first region becomes the darkest is calculated as the angle Δ. The second pixel is also operated in the same manner. The second region is compared with the first region, and the same angle Δ is calculated. Then, the average value of the angle Δ values of the first pixel and the second pixel is calculated as the angle Δ of the liquid crystal cell. The value of the angle Δ of this liquid crystal cell is 0.15 ° or less is evaluated as good, and the value above 0.15 ° is evaluated as bad.

[Mixing characteristics of accumulated charge] The above 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 short-circuited and made to the same potential, The LED backlight is irradiated from under the two polarizing plates in advance, and the angle of the liquid crystal cell is adjusted so that the brightness of the LED backlight penetrating light measured above the two polarizing plates is minimized. Next, a rectangular wave with a frequency of 30 Hz was applied to the liquid crystal cell, and the V-T characteristic (voltage-transmittance characteristic) at a temperature of 23 ° C. was measured at the same time to calculate an AC voltage with a relative transmittance of 23%. Since this AC voltage should be a region where the change of brightness to voltage is large, it is just appropriate to evaluate the accumulated charge through brightness.

Secondly, after applying an AC voltage having a relative transmittance of 23% and a rectangular wave having a frequency of 30 Hz for 5 minutes, a DC voltage of +1.0 V was superimposed to drive it for 30 minutes. Thereafter, the DC voltage was cut off, and only an AC voltage having a relative transmittance of 23% and a rectangular wave having a frequency of 30 Hz was applied again for 30 minutes. The faster the accumulated charge is relaxed, the faster the charge accumulation of the liquid crystal cell is when the DC voltage is superimposed. The easing characteristic of the accumulated charge is a state where the relative transmittance immediately after the superimposed DC voltage is 30% or more. The time required to reduce to 23% was evaluated. The shorter this time, the better the relaxation characteristics of the accumulated charge.

<Examples 5 to 6 and Comparative Examples 5 to 6> The liquid crystal alignment agents Q-1 to Q-2 obtained in Examples 3 to 4 and the liquid crystal alignment agents Q3 to Q4 obtained in Comparative Examples 3 to 4 were used to measure the ion density. 3. Stability evaluation of liquid crystal alignment and evaluation of relaxation characteristics of accumulated charge. The results are shown in Table 1.

[Industrial availability]

The liquid crystal alignment film of the present invention is particularly used in a liquid crystal display element of an IPS driving method or an FFS driving method which must be subjected to a rubbing treatment. Since the ion density in the liquid crystal display element can be suppressed from being lowered, and the accumulated electric charge can be quickly relaxed, The deviation between the rubbing direction and the alignment direction of the liquid crystal is suppressed, so that display performance with excellent afterimage characteristics and contrast can be obtained. Therefore, it is particularly useful as a liquid crystal alignment film used as a liquid crystal display element of an IPS driving method or an FFS driving method, a multifunctional mobile phone (smart phone), a tablet personal computer, and an LCD television.

Claims (11)

A liquid crystal alignment agent containing a polymer obtained from a diamine having a structure represented by the following formula (1); R ¹ represents a hydrogen atom, a linear or branchable alkyl or aryl group having 1 to 5 carbon atoms, and two R ¹ on the same maleimide ring may be the same as or different from each other, 2 Each R ¹ can also form an alkylene group having 3 to 6 carbon atoms, W ² represents a divalent organic group, W ¹ represents a single bond or a carbonyl group, and L ¹ represents a linear alkylene group selected from carbon atoms 1 to 20 , Branched alkylene groups of 3 to 20 carbon atoms, cyclic alkylene groups of 3 to 20 carbon atoms, diphenyl groups of phenylene and heterocyclic groups, or groups formed by plural bonding of the divalent groups The phenylene and heterocyclic groups are each independently and may be substituted by one or more substituents which are the same or different and are selected from the group consisting of alkyl, alkoxy, haloalkyl, haloalkoxy, halo and cyano. Substituting, the bonding of the divalent groups to each other is at least one selected from the group consisting of a single bond, an ester bond, a amine bond, a urea bond, an ether bond, a thioether bond, an amine bond, and a carbonyl group. When the divalent group is plural, The divalent radicals may be the same as or different from each other. When the above-mentioned bonding is plural, the bondings may be the same or different from each other. R represents a hydrogen atom or a monovalent organic group, and two Rs may be different from each other. , 2 R can also form an alkylene group with 1 to 6 carbon atoms together R 2 or any one of the two may be bonded to L ^1. The liquid crystal alignment agent according to claim 1, wherein the aforementioned W ¹ represents a single bond. The liquid crystal alignment agent according to claim 1, wherein the aforementioned polymer is at least one selected from the group consisting of a polyimide precursor containing a structural unit represented by the following formula (3), and a polyimide of a fluorimidate; 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 a structure of formula (1), and R ⁴ represents a hydrogen atom or an alkane having 1 to 5 carbon atoms base. The liquid crystal alignment agent according to claim 3, wherein in the foregoing formula (3), the structure of X ¹ represents at least one selected from the following structures; . The liquid crystal alignment agent according to claim 3, wherein the polymer is at least one selected from the group consisting of a polyimide precursor that further includes a structural unit represented by the following formula (4), and a polyimide of a fluorimidate. ; In formula (4), X ² represents a tetravalent organic group derived from a tetracarboxylic acid derivative, and Y ² represents a divalent organic group derived from a diamine that does not include a structure of formula (1) in the main chain direction, and R ¹⁴ Each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and R ¹⁵ is each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. The liquid crystal alignment agent according to claim 5, wherein the aforementioned Y ² is represented by the following formula (11); In formula (11), 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- If it is not adjacent, it can also be replaced by ether, ester, amidine, urea, carbamate bond; R ³⁴ represents a single bond or a divalent organic group; any hydrogen on the benzene ring The atom may be substituted by a monovalent organic group. For example, the liquid crystal alignment agent of claim 4, wherein the structural unit represented by the above formula (3) is 10 mol% or more with respect to the full structural unit of the polymer. A liquid crystal alignment film comprising the liquid crystal alignment agent according to any one of claims 1 to 7. A liquid crystal display element is provided with the liquid crystal alignment film according to claim 8. A diamine having a structure represented by the following formula (1); R ¹ represents a hydrogen atom, a linear or branchable alkyl or aryl group having 1 to 5 carbon atoms, and two R ¹ on the same maleimide ring may be the same as or different from each other, 2 Each R ¹ can also form an alkylene group having 3 to 6 carbon atoms, W ² represents a divalent organic group, W ¹ represents a single bond or a carbonyl group, and L ¹ represents a linear alkylene group selected from carbon atoms 1 to 20 , Branched alkylene groups of 3 to 20 carbon atoms, cyclic alkylene groups of 3 to 20 carbon atoms, diphenyl groups of phenylene and heterocyclic groups, or groups formed by plural bonding of the divalent groups The phenylene and heterocyclic groups are each independently and may be substituted by one or more substituents which are the same or different and are selected from the group consisting of alkyl, alkoxy, haloalkyl, haloalkoxy, halo and cyano. Substituting, the bonding of the divalent groups to each other is at least one selected from the group consisting of a single bond, an ester bond, a amine bond, a urea bond, an ether bond, a thioether bond, an amine bond, and a carbonyl group. When the divalent group is plural, The divalent radicals may be the same as or different from each other. When the above-mentioned bonding is plural, the bondings may be the same or different from each other. R represents a hydrogen atom or a monovalent organic group, and two Rs may be different from each other. , 2 R can also form an alkylene group with 1 to 6 carbon atoms together R 2 or any one of the two may be bonded to L ^1. A polymer obtained by using a diamine as claimed in claim 10.