WO2023008203A1

WO2023008203A1 - Liquid crystal aligning agent, liquid crystal alignment film, liquid crystal display element, compound and polymer

Info

Publication number: WO2023008203A1
Application number: PCT/JP2022/027644
Authority: WO
Inventors: 歳幸遠藤; 雅倫尹; 司藤枝; 達也結城; 達哉名木
Original assignee: 日産化学株式会社
Priority date: 2021-07-30
Filing date: 2022-07-14
Publication date: 2023-02-02
Also published as: KR20240037999A; CN117716282A; TW202309155A; JPWO2023008203A1

Abstract

A liquid crystal aligning agent which contains a polymer (A) that is obtained by a polymerization reaction of a diamine component and a tetracarboxylic acid derivative component that contains a diimide diester compound (B) represented by formula (1), wherein the polymer (A) has a group that is derived from the diimide diester compound (B) and is represented by formula (1A). In formula (1), X1 represents a tetravalent organic group that is derived from an acyclic aliphatic tetracarboxylic acid dianhydride, an alicyclic tetracarboxylic acid dianhydride or a derivative thereof; and each R independently represents a monovalent organic group having 1 to 5 carbon atoms. In formula (1A), R represents a monovalent organic group having 1 to 5 carbon atoms; and * represents a bonding hand that is bonded to X1.

Description

liquid crystal alignment agent, liquid crystal alignment film, liquid crystal display element, compound, and polymer

The present invention relates to liquid crystal aligning agents, liquid crystal aligning films, liquid crystal display elements, and compounds and polymers that can be used therefor.

Conventionally, liquid crystal display devices have been widely used as display units for personal computers, smartphones, mobile phones, television receivers, and the like. A liquid crystal display device includes, for example, a liquid crystal layer sandwiched between an element substrate and a color filter substrate, a pixel electrode and a common electrode for applying an electric field to the liquid crystal layer, an alignment film for controlling the orientation of liquid crystal molecules in the liquid crystal layer, A thin film transistor (TFT) or the like is provided for switching an electric signal supplied to the pixel electrode. Driving methods for liquid crystal molecules include vertical electric field methods such as the TN (Twisted Nematic) method and VA (Vertical Alignment) method, and horizontal electric field methods such as the IPS (In-Plane Switching) method and the FFS (Fringe Field Switching) method. Are known.

Currently, the liquid crystal alignment film that is most widely used industrially is formed on an electrode substrate, and the surface of a film made of a polymer typified by polyamic acid and/or polyimide imidized thereof is coated with cotton, nylon, or the like. It is produced by rubbing in one direction with a cloth such as polyester. The rubbing treatment is a simple, highly productive and industrially useful method. However, along with the high performance, high definition, and large size of liquid crystal display elements, scratches on the surface of the alignment film caused by rubbing, dust generation, mechanical force and static electricity, and furthermore, the alignment processing surface Various problems such as non-uniformity of . As an alignment treatment method that replaces the rubbing treatment, there is known a photo-alignment method in which polarized radiation is applied to impart liquid crystal alignment ability. As the photo-alignment method, a method using a photoisomerization reaction, a method using a photocrosslinking reaction, a method using a photodecomposition reaction, and the like have been proposed (see, for example, Non-Patent Document 1 and Patent Document 1).

Liquid crystal alignment films used in liquid crystal display elements of the IPS driving method and the FFS driving method are required to have a high alignment regulating force for suppressing afterimages (hereinafter also referred to as AC afterimages) generated by long-term AC driving. .
Patent Literature 2 proposes a polyimide precursor having a specific structure or a liquid crystal aligning agent containing polyimide as a means for solving the above problems.

JP-A-9-297313 WO2016/152928

In recent years, large-screen, high-definition liquid crystal display elements have become the main focus, and the demand for high quality liquid crystal display elements is increasing more than ever before. In particular, as the size of the liquid crystal display element increases, a problem arises that the twist angle of the liquid crystal within the plane of the liquid crystal display element varies slightly due to variations in the manufacturing process. Such variations lead to non-uniform brightness in the plane of the liquid crystal display element when black is displayed, leading to deterioration of the quality of the liquid crystal display element.

In view of the above, an object of the present invention is to obtain a liquid crystal alignment film that has a small variation (non-uniformity) in the twist angle of the liquid crystal in the plane of the liquid crystal alignment film and can suppress the AC afterimage. An aligning agent, a liquid crystal aligning film obtained from the liquid crystal aligning agent, a liquid crystal display device using the liquid crystal aligning film, and compounds and polymers that can be used for them are provided.

As a result of intensive research to achieve the above object, the present inventors have found that a liquid crystal aligning agent containing a polymer having a specific compound as a constituent is extremely effective for achieving the above object. He found this and completed the present invention.

The present invention includes the following aspects.
At least one compound selected from the group consisting of tetracarboxylic dianhydrides and derivatives thereof (excluding tetracarboxylic acid diimide diester compounds) and a diimide diester compound (B) represented by the following formula (1) Contains one or more polymers (A) selected from the group consisting of polyimide precursors obtained by polymerizing a tetracarboxylic acid derivative component and a diamine component, and polyimides that are imidized products of the polyimide precursors. death,
The polymer (A) has a group represented by the following formula (1A) derived from the diimide diester compound (B),
Liquid crystal aligning agent.

(X ₁ represents a tetravalent organic group derived from an acyclic aliphatic tetracarboxylic dianhydride or an alicyclic tetracarboxylic dianhydride or a derivative thereof. Each R independently represents a carbon represents a monovalent organic group of numbers 1 to 5.)

(R represents a monovalent organic group having 1 to 5 carbon atoms. * represents a bond that binds to X _1. )

ADVANTAGE OF THE INVENTION According to this invention, the liquid crystal aligning agent which can obtain the liquid crystal aligning film which has a small variation (non-uniformity) of the twist angle of the liquid crystal in a liquid crystal aligning film plane, and can suppress an AC afterimage, and this liquid crystal aligning agent. It is possible to provide a liquid crystal alignment film obtained from, a liquid crystal display element using the liquid crystal alignment film, a compound that can be used for them, and a polymer.
Although the mechanism by which the above effects are obtained by the present invention is not necessarily clear, the following is considered to be one of the reasons. It is believed that the portion derived from the diimide diester compound (B) in the polymer (A) is less likely to be imidized during baking, so that the amount of decomposition during irradiation with polarized ultraviolet rays is suppressed and the reorientation of the polymer is improved. be done. Further, when the polymer having the group represented by the formula (1A) contains two or more types of polymers, the effect of increasing the uneven distribution to the surface layer is exhibited, so it is considered that the above effect is exhibited.

Hereinafter, a liquid crystal aligning agent containing a specific polymer, a liquid crystal aligning film formed using the liquid crystal aligning agent, and a liquid crystal display element having the liquid crystal aligning film will be described in detail. is an example as one embodiment of the present invention, and is not limited to these contents.
In the following description, "halogen atom" includes fluorine atom, chlorine atom, bromine atom, iodine atom and the like. "Boc" represents a tert-butoxycarbonyl group, and "*" represents a binding position.

<Polymer (A)>
The liquid crystal aligning agent of this invention contains a polymer (A).
The polymer (A) is one or more selected from the group consisting of polyimide precursors and polyimides which are imidized products of the polyimide precursors.
A polyimide precursor is obtained by polymerizing a tetracarboxylic acid derivative component and a diamine component.
The tetracarboxylic acid derivative component is at least one compound selected from the group consisting of tetracarboxylic dianhydrides and derivatives thereof (excluding tetracarboxylic acid diimide diester compounds). Also referred to as an anhydride compound.) and the diimide diester compound (B) represented by the above formula (1).
The polymer (A) has a group represented by the formula (1A) derived from the diimide diester compound (B).
Examples of the polyimide precursor include polyamic acid and polyamic acid ester. Examples of the tetracarboxylic dianhydride derivatives include tetracarboxylic acid dihalides, tetracarboxylic acid dialkyl esters, and tetracarboxylic acid dialkyl ester dihalides.
In addition, the polymer (A) itself is also an object of the present invention independently of the liquid crystal aligning agent of the present invention.

<<Polymer (A)>>
When the polymer (A) is a polyamic acid, the polymer (A) is, for example, a tetracarboxylic acid containing a tetracarboxylic dianhydride and a diimide diester compound (B) represented by the formula (1). It is obtained by polymerizing (polycondensing) a derivative component and a diamine component. The polyimide in the polymer (A) is obtained by imidizing the polyamic acid. Further, when the polymer (A) is a polyamic acid ester, it can be obtained by the method described later, and a polyimide is obtained by imidating the polyamic acid ester.

<<<tetracarboxylic dianhydride-based compound>>>
Examples of the tetracarboxylic dianhydride compounds include aromatic tetracarboxylic dianhydrides, acyclic aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, and derivatives thereof. be done. Here, the aromatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups including at least one carboxy group bonded to an aromatic ring. An acyclic aliphatic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups bonded to a chain hydrocarbon structure. However, it does not need to be composed only of a chain hydrocarbon structure, and may have an alicyclic structure or an aromatic ring structure in part thereof.

An alicyclic tetracarboxylic dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups including at least one carboxy group bonded to an alicyclic structure. However, none of these four carboxy groups are bonded to the aromatic ring.
Moreover, it is not necessary to consist only of an alicyclic structure, and a part thereof may have a chain hydrocarbon structure or an aromatic ring structure.

The aromatic tetracarboxylic dianhydride, acyclic aliphatic tetracarboxylic dianhydride or alicyclic tetracarboxylic dianhydride is, among others, a tetracarboxylic dianhydride represented by the following formula (2) is preferred.

(X represents a structure selected from the group consisting of the following formulas (x-1) to (x-18) and (xr-1) to (xr-2).)

(R ¹ to R ⁴ each independently contain a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, or a fluorine atom. R ⁵ represents a monovalent organic group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 6 carbon atoms, an alkyloxycarbonyl group having 2 to 6 carbon atoms, or a phenyl group. and ^R6 each independently represent a hydrogen atom or a methyl group.
in formula (x-9)

represents a single bond or a double bond.
j and k are integers of 0 or 1, and A ₁ and A ₂ each independently represent a single bond, —O—, —CO—, —COO—, a phenylene group, a sulfonyl group, or an amide group; show. A plurality of A ₂ may be the same or different. *1 is a bond that bonds to one acid anhydride group, and *2 is a bond that bonds to the other acid anhydride group. )

Preferred specific examples of the tetracarboxylic dianhydride represented by the above formula (2) include X being the above formulas (x-1) to (x-8), (x-10) to (x-11) , and (xr-1) to (xr-2).

The above formula (x-1) is preferably selected from the group consisting of the following formulas (x1-1) to (x1-6).

(*1 is a bond that bonds to one acid anhydride group, and *2 is a bond that bonds to the other acid anhydride group.)

Preferable specific examples of the above formulas (xr-1) and (xr-2) include the following formulas (xr-3) to (xr-18).

<<<diimide diester compound (B)>>>
The polymer (A) of the present invention is obtained by using a tetracarboxylic acid derivative component containing the diimide diester compound (B) represented by the above formula (1). By adopting such a mode, it is possible to provide the resulting liquid crystal alignment film with high AC afterimage resistance and small variation (non-uniformity) in the twist angle when used as a liquid crystal display device.
In addition, independently of the liquid crystal aligning agent of this invention, the diimide diester compound (B) itself is also the object of this invention.

The monovalent organic group having 1 to 5 carbon atoms for R in the above formula (1) includes an alkyl group having 1 to 5 carbon atoms (e.g., methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, isobutyl group, tert-butyl group, etc.), alkenyl groups having 2 to 5 carbon atoms (vinyl group, 2-propenyl group, etc.), alkynyl groups having 2 to 5 carbon atoms (2-propynyl group, etc. ), or a heteroatom-containing group including a group having a heteroatom between the carbon-carbon bonds of these groups, the above alkyl groups, alkenyl groups, alkynyl groups and heteroatom-containing groups replace some or all of the hydrogen atoms A group substituted with a group is mentioned.

Groups having a heteroatom include, for example, groups having at least one selected from the group consisting of an oxygen atom, a nitrogen atom, a silicon atom, a phosphorus atom and a sulfur atom, and the like, -O-, -NR-(R represents a hydrogen atom or a methyl group.), -CO-, -S-, -CO-, -Si(R')(R')-(R' is each independently alkyl having 1 to 3 carbon atoms represents a group.), and groups in which these are combined. Of these, -O- is preferred.

Examples of the substituents include halogen atoms; alkoxy groups such as methoxy, ethoxy and propoxy; alkoxycarbonyl groups such as methoxycarbonyl and ethoxycarbonyl; alkoxycarbonyloxy such as methoxycarbonyloxy and ethoxycarbonyloxy; Group; cyano group, nitro group, hydroxy group and the like.

From the viewpoint of enhancing the liquid crystal orientation, each R in the above formula (1) is independently an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, or It is preferably a group in which some or all of the hydrogen atoms of the alkyl group, alkenyl group or alkynyl group are substituted with a substituent.

X ₁ in the above formula (1) represents a tetravalent organic group derived from an acyclic aliphatic tetracarboxylic dianhydride, an alicyclic tetracarboxylic dianhydride, or a derivative thereof. Specific examples of the acyclic aliphatic tetracarboxylic dianhydride that gives the diimide diester compound (B) represented by the above formula (1) include intramolecular dehydration of four carboxy groups bonded to a chain hydrocarbon structure. It is an acid dianhydride obtained by However, it does not need to be composed only of a chain hydrocarbon structure, and may have an alicyclic structure or an aromatic ring structure in part thereof.
The chain hydrocarbon structure preferably has 2 to 15 carbon atoms. The chain hydrocarbon structure may be linear or branched, and the chain hydrocarbon structure includes an oxygen atom-containing group (—O—, —CO—, etc.) and/or a nitrogen atom-containing group ( secondary, tertiary, quaternary amines, etc.) and/or sulfur atom-containing groups (-S-, -CS-, etc.) may be included. Moreover, the chain hydrocarbon structure may be a saturated hydrocarbon structure or an unsaturated hydrocarbon structure.
Preferred specific examples of the case where X ₁ in the above formula (1) represents a tetravalent organic group derived from an acyclic aliphatic tetracarboxylic dianhydride or a derivative thereof include the above formula (x-8), (x-10), or (x-12).

Specific examples of the alicyclic tetracarboxylic dianhydride that gives the diimide diester compound (B) represented by the above formula (1) include four carboxy groups including at least one carboxy group that bonds to the alicyclic structure. It is an acid dianhydride obtained by intramolecular dehydration of the group. However, none of these four carboxy groups are bonded to the aromatic ring. Moreover, it is not necessary to consist only of an alicyclic structure, and a part thereof may have a chain hydrocarbon structure or an aromatic ring structure.
The alicyclic structure preferably has 3 to 20 carbon atoms, more preferably 4 to 20 carbon atoms. The alicyclic structure includes oxygen atom-containing groups (-O-, -CO-, etc.) and/or nitrogen atom-containing groups (secondary, tertiary, quaternary amines, etc.) and/or sulfur Atom containing groups (-S-, -CS-, etc.) may be included. Moreover, the alicyclic structure may be a saturated alicyclic structure or an unsaturated alicyclic structure.
Preferred specific examples of the case where X ₁ in the above formula (1) represents a tetravalent organic group derived from an alicyclic tetracarboxylic dianhydride or a derivative thereof include the above formula (x-1). be done.

Among them, from the viewpoint of suitably obtaining the effects of the present invention, X ₁ in formula (1) is an acyclic aliphatic hydrocarbon group having 4 to 16 carbon atoms or an alicyclic aliphatic hydrocarbon group having 4 to 16 carbon atoms. It is preferably a tetravalent organic group derived from a tetracarboxylic dianhydride or a derivative thereof, and more preferably represented by any one of formulas (x-1) to (x-18).

Particularly preferably, the diimide diester compound represented by the above formula (1) is any one of the compounds represented by the following formulas (b-1) to (b-9).

The amount of the diimide diester compound (B) represented by the above formula (1) used when producing the polymer (A) is 1 mol per 1 mol of the total tetracarboxylic acid derivative component to be reacted with the diamine component. % or more is preferable, and 5 mol % or more is more preferable.
Further, the amount of the tetracarboxylic acid dianhydride represented by the above formula (2) or a derivative thereof when producing the polymer (A) is On the other hand, 99 mol% or less is preferable, and 95 mol% or less is more preferable.

<<<<Method for producing diimide diester compound (B)>>>>
The method for obtaining the diimide diester compound (B) is described below. Although the method for synthesizing the diimide diester compound of the present invention is not particularly limited, for example, a method of synthesizing by reacting the diimide compound (DI-0) with a dicarbonic acid diester compound can be mentioned.

Dicarbonic acid diester compounds can be purchased from reagent companies. Examples thereof include di-tert-butyl dicarbonate, diallyl dicarbonate, di-tert-amyl dicarbonate, and the like represented by the following formulas.

The reaction can be carried out in the presence of a catalyst. Catalysts include, for example, 4-dimethylaminopyridine.

Although not a catalytic reaction, a method of adding sodium iodide to react a diimide compound with a dicarbonic acid diester has also been reported (Journal of Chemical and Pharmaceutical Research (2016), 8(1), 510-518).

Examples of reaction solvents include aprotic polar organic solvents (DMF (N,N-dimethylformamide), DMSO (dimethylsulfoxide), DMAc (N,N-dimethylacetamide), NMP (N-methyl-2-pyrrolidone), etc.). Ethers (Et ₂ O (diethyl ether), i-Pr ₂ O (diisopropyl ether), TBME (tert-butyl methyl ether), CPME (cyclopentyl methyl ether), THF (tetrahydrofuran), dioxane, etc.); Aliphatic carbonization Hydrogens (pentane, hexane, heptane, petroleum ether, etc.); Aromatic hydrocarbons (benzene, toluene, xylene, mesitylene, chlorobenzene, dichlorobenzene, nitrobenzene, tetralin, etc.); Halogen hydrocarbons (chloroform, dichloromethane, carbon tetrachloride, dichloroethane, etc.); lower fatty acid esters (methyl acetate, ethyl acetate, butyl acetate, methyl propionate, etc.); nitriles (acetonitrile, propionitrile, butyronitrile, etc.); alcohols (methanol, ethanol, 2- propanol, etc.) can be used. These solvents can be appropriately selected in consideration of the easiness of reaction and the like, and can be used singly or in combination of two or more.

The reaction temperature can preferably be selected from a temperature range of -10°C or higher to the boiling point of the reaction solvent used. The reaction time is 0.1 to 1000 hours, more preferably 0.5 to 100 hours.
The diimide diester compound (B) obtained by the above reaction is preferably purified by recrystallization or column chromatography using silica gel or the like.

As another method, the diimide diester compound (B) can be obtained by reacting the diimide compound (DI-0) and the chloroformate compound in the presence of a base such as triethylamine.

Chloroformate compounds can be purchased from reagent companies. Examples thereof include methyl chloroformate, ethyl chloroformate, allyl chloroformate, isopropyl chloroformate, propyl chloroformate, isobutyl chloroformate, butyl chloroformate, 2-methoxyethyl chloroformate, amyl chloroformate, and the like represented by the following formulas. .

Bases include inorganic bases such as sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, potassium phosphate, sodium carbonate, potassium carbonate, lithium carbonate, and cesium carbonate; methylamine, dimethylamine, trimethylamine; , ethylamine, diethylamine, triethylamine, propylamine, dipropylamine, tripropylamine, isopropylamine, diisopropylamine, triisopropylamine, butylamine, dibutylamine, tributylamine, diisopropylethylamine, pyridine, imidazole, quinoline, collidine, pyrrolidine, piperidine , morpholine, and N-methylmorpholine.

Examples of reaction solvents include water, aprotic polar organic solvents (DMF, DMSO, DMAc, NMP, etc.); ethers (Et ₂ O, i-Pr ₂ O, TBME, CPME, THF, dioxane, etc.); Hydrogens (pentane, hexane, heptane, petroleum ether, etc.); Aromatic hydrocarbons (benzene, toluene, xylene, mesitylene, chlorobenzene, dichlorobenzene, nitrobenzene, tetralin, etc.); Halogen hydrocarbons (chloroform, dichloromethane, carbon tetrachloride, dichloroethane, etc.); lower fatty acid esters (methyl acetate, ethyl acetate, butyl acetate, methyl propionate, etc.); nitriles (acetonitrile, propionitrile, butyronitrile, etc.). These solvents can be appropriately selected in consideration of the easiness of reaction and the like, and can be used singly or in combination of two or more.

A diimide compound (DI-0) can be obtained by reacting a tetracarboxylic dianhydride with an ammonium compound.

Ammonium compounds can be purchased from reagent companies. Examples include ammonium chloride, ammonium acetate, hydroxylamine hydrochloride, ammonium hydroxide (ammonia water), urea, formamide and the like.

Any reaction solvent can be used as long as it is stable under the reaction conditions, inert and does not interfere with the reaction. As a reaction solvent, acetic acid, aprotic polar organic solvents (DMF, DMSO, DMAc, NMP, etc.), ethers (Et ₂ O, i-Pr ₂ O, TBME, CPME, THF, dioxane, etc.), aliphatic hydrocarbons (pentane, hexane, heptane, petroleum ether, etc.), aromatic hydrocarbons (benzene, toluene, xylene, mesitylene, chlorobenzene, dichlorobenzene, nitrobenzene, tetralin, etc.), halogenated hydrocarbons (chloroform, dichloromethane, tetraline, etc.) carbon chloride, dichloroethane, etc.), lower fatty acid esters (methyl acetate, ethyl acetate, butyl acetate, methyl propionate, etc.), nitriles (acetonitrile, propionitrile, butyronitrile, etc.). These solvents can be appropriately selected in consideration of the easiness of reaction and the like, and can be used singly or in combination of two or more.

The reaction temperature can preferably be selected from a temperature range of -10°C or higher to the boiling point of the reaction solvent used. The reaction time is 0.1 to 1000 hours, more preferably 0.5 to 100 hours.
The diimide compound (DI-0) obtained by the above reaction is preferably purified by recrystallization or column chromatography using silica gel or the like.

<<<diamine component>>>
Although the diamine component used for producing the polyimide precursor is not particularly limited, a diamine component containing a diamine represented by the following formula (3) is preferable.

(Ar ₁ and Ar _1′ each represent a benzene ring, a biphenyl structure, or a naphthalene ring, and one or more hydrogen atoms on the benzene ring, the biphenyl structure, or the naphthalene ring are monovalent groups; optionally substituted, L ₁ and L _1′ each represent a single bond, —O—, —C(=O)—, or —OC(=O)—, A is —CH ₂ -, an alkylene group having 2 to 12 carbon atoms, or at least -O-, -C(=O)-O-, and -OC(=O)- between the carbon-carbon bonds of the alkylene group represents a divalent organic group into which any group is inserted.Any hydrogen atom of A may be substituted with a halogen atom.)

Ar ₁ and Ar _1′ in formula (3) above each represent a benzene ring, a biphenyl structure, or a naphthalene ring. One or more hydrogen atoms on the benzene ring, biphenyl structure, or naphthalene ring may be substituted with a monovalent group, and the monovalent group includes a halogen atom, an alkyl group having 1 to 3 carbon atoms, a carbon alkenyl group having 2 to 3 carbon atoms, alkoxy group having 1 to 3 carbon atoms, fluoroalkyl group having 1 to 3 carbon atoms, fluoroalkenyl group having 2 to 3 carbon atoms, fluoroalkoxy group having 1 to 3 carbon atoms, 2 carbon atoms to 3 alkyloxycarbonyl groups, cyano groups, nitro groups, and the like.

In Ar ₁ and Ar _1′ in the above formula (3), the bonding position between the amino group and L ₁ or L _1′ with respect to the benzene ring is more preferably 1,4-position or 1,3-position. , 1,4-positions are more preferred. The binding positions of the amino group and L ₁ or L _1′ with respect to the biphenyl structure are more preferably 4,4′-positions or 3,3′-positions, more preferably 4,4′-positions. As for the bonding positions of the amino group and L ₁ or L _1′ with respect to the naphthalene ring, the bonding positions of the naphthalene ring are more preferably 1,5-positions or 2,6-positions, and still more preferably 2,6-positions.

A represents -CH ₂ -, or represents an alkylene group having 2 to 12 carbon atoms, or between the carbon-carbon bonds of the alkylene group, -O-, -C(=O)-O- , and —O—C(=O)— represents a divalent organic group into which at least one group is inserted. Any hydrogen atom of A may be substituted with a halogen atom.
The alkylene group having 2 to 12 carbon atoms may be linear or branched, but is preferably linear.
-O-, -C(=O)-O-, and -OC(=O)- inserted into the divalent organic group may be one or more good.

Preferred specific examples of the group —L ₁ —AL _1′ — in formula (3) are shown below.
—(CH ₂ ) _n —,
—O—(CH ₂ ) _n —,
—O—(CH ₂ ) _n —O—,
-C(=O)-(CH ₂ ) _n -C(=O)-,
-O-C(=O)-( _CH2 ) _n -O-,
-O-C(=O)-( _CH2 ) _n -O-C(=O)-,
-O-C(=O)-( _CH2 ) _n -C(=O)-O-,
-C(=O)-O-( _CH2 ) _n -O-C(=O)-,
—(CH ₂ ) _m1 —O—(CH ₂ ) _n′ —O—(CH ₂ ) _m2 —,
-(CH ₂ ) _m1 -O-C(=O)-(CH ₂ ) _n' -C(=O)-O-(CH ₂ ) _m2 -,
-(CH ₂ ) _m1 -C(=O)-O-(CH ₂ ) _n' -O-C(=O)-(CH ₂ ) _m2 -

In preferred embodiments of the group -L ₁ -AL _1′ - above, n is an integer of 1-12, more preferably an integer of 2-12, and even more preferably an integer of 2-6.
The sum of m1, m2 and n' is an integer of 3-12, more preferably an integer of 6-12. Each of m1 and m2 is more preferably an integer of 1 to 4, and still more preferably an integer of 2 to 4. n′ is more preferably an integer of 2-6, and even more preferably an integer of 2-4.

The ratio of the diamine represented by the formula (3) is preferably 1 mol% or more, more preferably 10 mol% or more, and further preferably 20 mol% or more with respect to 1 mol of the diamine component. preferable.

The polymer (A) may contain diamines other than the diamines described above. Examples of other diamines are listed below, but the present invention is not limited to these. In addition to the diamine represented by the above formula (3), when other diamines are used in combination, the amount of the diamine represented by the formula (3) to the diamine component is preferably 90 mol% or less, and 80 mol%. The following are more preferred. Examples of other diamines are listed below, but the present invention is not limited to these. The other diamines may be used singly or in combination of two or more.

p-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, m-phenylenediamine, 2,4-dimethyl-m-phenylenediamine, 1, 4-diamino-2,5-methoxybenzene, 2,5-diaminotoluene, 2,6-diaminotoluene, 4-aminobenzylamine, 2-(4-aminophenyl)ethylamine, 4-(2-(methylamino) ethyl)aniline, 4-(2-aminoethyl)aniline, 2-(6-aminonaphthyl)ethylamine, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4' -diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 3-trifluoromethyl-4,4'-diaminobiphenyl, 2- trifluoromethyl-4,4'-diaminobiphenyl, 3-fluoro-4,4'-diaminobiphenyl, 2-fluoro-4,4'-diaminobiphenyl, 2,2'-difluoro-4,4'-diaminobiphenyl , 3,3′-difluoro-4,4′-diaminobiphenyl, 2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl, 3,3′-bis(trifluoromethyl)-4, 4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 4,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'-diaminobiphenyl, 2,3'-diaminobiphenyl, 1,5- Diaminonaphthalene, 1,6-diaminonaphthalene, 1,7-diaminonaphthalene, 2,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,7-diaminonaphthalene; N,N'-bis(4-aminophenyl) -cyclobutane-(1,2,3,4)-tetracarboxylic diimide, N,N'-bis(4-aminophenyl)-1,3-dimethylcyclobutane-(1,2,3,4)-tetracarboxylic acid diimide, N,N'-bis(2,2'-bis(trifluoromethyl)-4'-amino-1,1'-biphenyl-4-yl)-cyclobutane-(1,2,3,4) - diamines having a tetracarboxylic diimide structure, such as tetracarboxylic diimide;

1,4-phenylene bis(4-aminobenzoate), 1,4-phenylene bis(3-aminobenzoate), 1,3-phenylene bis(4-aminobenzoate), 1,3-phenylene bis(3-aminobenzoate ), bis(4-aminophenyl) terephthalate, bis(3-aminophenyl) terephthalate, bis(4-aminophenyl) isophthalate, bis(3-aminophenyl) isophthalate; 4,4′-diaminoazobenzene, diaminotran , 4,4-diaminochalcone, or [4-[(E)-3-[2-(2,4-diaminophenyl)ethoxy]-3-oxo-prop-1-enyl]phenyl]4-(4, 4,4-trifluorobutoxy)benzoate, or [4-[(E)-3-[[5-amino-2-[4-amino-2-[[(E)-3-[4-[4- (4,4,4-trifluorobutoxy)benzoyl]oxyphenyl]prop-2-enoyl]oxymethyl]phenyl]phenyl]methoxy]-3-oxo-prop-1-enyl]phenyl]4-(4,4 ,4-trifluorobutoxy) diamines having photoalignable groups such as aromatic diamines having a cinnamate structure typified by benzoate; 2-(2,4-diaminophenoxy)ethyl methacrylate or 2,4-diamino-N , N-diallylaniline and other photopolymerizable group-terminated diamines; 1-(4-(2-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylpropanone, 2- Diamines with a radical polymerization initiator function such as (4-(2-hydroxy-2-methylpropanoyl)phenoxy)ethyl-3,5-diaminobenzoate; Diamines with an amide bond such as 4,4′-diaminobenzanilide _diamines having a urea bond such as _4,4′ _- _{diaminodiphenylurea} ; Represents a protective group that replaces a hydrogen atom.) Represents a divalent organic group having a diamine having a thermally releasable group such as);

3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 4,4'-sulfonyldianiline, 3,3'-sulfonyldianiline, bis(4-aminophenyl)silane , bis(3-aminophenyl)silane, dimethyl-bis(4-aminophenyl)silane, dimethyl-bis(3-aminophenyl)silane, 4,4′-thiodianiline, 3,3′-thiodianiline, 1,4- bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 4,4'-diaminobenzophenone, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4 -aminophenyl)benzene, 1,4-bis(4-aminobenzyl)benzene; 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl -3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diamino Carbazole, N-(3-(1H-imidazol-1-yl)propyl-3,5-diaminobenzamide, 4-[4-[(4-aminophenoxy)methyl]-4,5-dihydro-4-methyl- 2-oxazolyl]-benzenamine, 4-[4-[(4-aminophenoxy)methyl]-4,5-dihydro-2-oxazolyl]-benzenamine, 1,4-bis(p-aminobenzyl)piperazine, 4,4′-[4,4′-propane-1,3-diylbis(piperidine-1,4-diyl)]dianiline, 4-(4-aminophenoxycarbonyl)-1-(4-aminophenyl)piperidine, 2,5-bis(4-aminophenyl)pyrrole, 4,4′-(1-methyl-1H-pyrrole-2,5-diyl)bis[benzenamine], 1,4-bis-(4-aminophenyl )-piperazine, 2-N-(4-aminophenyl)pyridine-2,5-diamine, 2-N-(5-aminopyridin-2-yl)pyridine-2,5-diamine, 2-(4-amino Phenyl)-5-aminobenzimidazole, 2-(4-aminophenyl)-6-aminobenzimidazole, 5-(1H-benzimidazol-2-yl)benzene-1,3-diamine, or the following formula (z- 1) ~ Represented by formula (z-5) or 4,4′-diaminodiphenylamine, 4,4′-diaminodiphenyl-N-methylamine, N,N′-bis(4-aminophenyl)-benzidine, N,N Diphenylamine structures such as '-bis(4-aminophenyl)-N,N'-dimethylbenzidine or N,N'-bis(4-aminophenyl)-N,N'-dimethyl-1,4-benzenediamine At least one nitrogen atom-containing structure selected from the group consisting of a heterocyclic ring containing a nitrogen atom, a secondary or tertiary amino group (provided that -N (D) - (D is It represents a protective group that is eliminated by heating and replaced with a hydrogen atom. ) except amino groups derived from );

2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 4,4'-diamino-3,3'-dihydroxy Biphenyl; 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, 4,4'-diaminobiphenyl-3-carboxylic acid, 4,4'-diaminodiphenylmethane-3-carboxylic acid acid, 1,2-bis(4-aminophenyl)-3-carboxylic acid, 4,4'-diaminobiphenyl-3,3'-dicarboxylic acid, 4,4'-diaminobiphenyl-2,2'-dicarboxylic acid , 3,3′-diaminobiphenyl-4,4′-dicarboxylic acid, 3,3′-diaminobiphenyl-2,4′-dicarboxylic acid, 4,4′-diaminodiphenylmethane-3,3′-dicarboxylic acid, 1 , 2-bis(4-aminophenyl)-3,3′-dicarboxylic acid, 4,4′-diaminodiphenyl ether-3,3′-dicarboxylic acid and other diamines having a carboxyl group; 1-(4-aminophenyl) -1,3,3-trimethyl-1H-indan-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-indene-6-amine; cholestanil Oxy-3,5-diaminobenzene, Cholestenyloxy-3,5-diaminobenzene, Cholestanyloxy-2,4-diaminobenzene, Cholestanyl 3,5-diaminobenzoate, Cholestenyl 3,5-diaminobenzoate, 3 diamines having a steroid skeleton such as lanostanyl, 5-diaminobenzoate and 3,6-bis(4-aminobenzoyloxy)cholestane; diamines represented by the following formulas (V-1) to (V-2); Diamines with siloxane bonds such as 3-bis(3-aminopropyl)-tetramethyldisiloxane; Alicyclic diamines such as aliphatic diamines, 1,3-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), formula (Y- 1) A diamine in which two amino groups are bonded to a group represented by any one of -(Y-167), and the like.

(In formula (V-1), m and n are each an integer of 0 to 3 (provided that 1 ≤ m + n ≤ 4), j is an integer of 0 or 1, and X ¹ is - (CH ₂ ) _a — (a is an integer of 1 to 15), —CONH—, —NHCO—, —CO—N(CH ₃ )—, —NH—, —O—, —CH ₂ O— , —CH ₂ —OCO—, —COO—, or —OCO—, wherein R ¹ is a fluorine atom, a fluorine atom-containing alkyl group having 1 to 10 carbon atoms, a fluorine atom-containing alkoxy group having 1 to 10 carbon atoms, represents an alkyl group having 3 to 10 carbon atoms, an alkoxy group having 3 to 10 carbon atoms, or an alkoxyalkyl group having 3 to 10 carbon atoms, wherein X ² is -O- or -CH ₂ O; -, -CH ₂ -OCO-, -COO-, or -OCO-, where R ² represents an alkyl group having 3 to 30 carbon atoms or a fluorine atom-containing alkyl group having 3 to 20 carbon atoms, m, n , X ¹ and R ¹ are each independently defined above.)

D in -N(D)- of the other diamines described above is a carbamate organic group represented by a benzyloxycarbonyl group, 9-fluorenylmethyloxycarbonyl group, allyloxycarbonyl group, Boc, and the like. is preferred. Boc is particularly preferable from the viewpoint that it is efficiently desorbed by heat, is desorbed at a relatively low temperature, and is discharged as a harmless gas when desorbed.

Preferred examples of diamines having a thermally leaving group exemplified as other diamines are diamines selected from the following formulas (d-1) to (d-7).

(In formulas (d-2), (d-6), and (d-7), R represents a hydrogen atom or Boc.)

When the diamine having the thermally-leaving group is used as the diamine component used in the production of the polyimide precursor, from the viewpoint of suitably obtaining the effect of the present invention, it is preferably 5 to 40 mol per 1 mol of the diamine component. %, more preferably 5 to 35 mol %, even more preferably 5 to 30 mol %.

The liquid crystal aligning agent of this invention may contain other polymers other than a polymer (A). Specific examples of other polymers include a polyimide precursor obtained using a tetracarboxylic acid derivative component and a diamine component that do not contain the diimide diester compound (B) represented by the above formula (1), and the polyimide precursor. At least one polymer (Q) selected from the group consisting of polyimides, polysiloxanes, polyesters, polyamides, polyureas, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene derivatives, poly(styrene-maleic anhydride material) copolymers, poly(isobutylene-maleic anhydride) copolymers, poly(vinyl ether-maleic anhydride) copolymers, poly(styrene-phenylmaleimide) derivatives, and poly(meth)acrylates and polymers selected from. From the viewpoint of increasing the voltage holding ratio, the polymer (Q) is selected from the group consisting of a polyimide precursor obtained using a diamine component containing a diamine having a nitrogen atom-containing structure and an imidized product of the polyimide precursor. and at least one polymer (Q'). Specific examples of poly(styrene-maleic anhydride) copolymers include SMA1000, SMA2000, SMA3000 (manufactured by Cray Valley), GSM301 (manufactured by Gifu Shellac Manufacturing Co., Ltd.) and the like. Anhydride) copolymers include Isoban-600 (manufactured by Kuraray Co., Ltd.), and specific examples of poly(vinyl ether-maleic anhydride) copolymers include Gantrez AN-139 (methyl vinyl ether anhydride). maleic acid resin, manufactured by Ashland).
Other polymers may be used singly or in combination of two or more. The content of the other polymer is more preferably 10 to 90 parts by mass, still more preferably 20 to 80 parts by mass, per 100 parts by mass of the polymer component contained in the liquid crystal aligning agent.
In addition, in this specification, a polymer component is a general term for other polymers other than a polymer (A) and a polymer (A) contained in a liquid crystal aligning agent. When the polymer contained in the liquid crystal aligning agent is only the polymer (A), the polymer component refers to the polymer (A).

As a tetracarboxylic acid derivative component for obtaining the polymer (Q′), for example, a tetracarboxylic acid derivative component containing a tetracarboxylic dianhydride-based compound exemplified for the polymer (A) (provided that the above formula ( 1) does not contain the diimide diester compound (B). Among them, the tetracarboxylic dianhydride represented by the above formula (2) or a derivative thereof is preferable. The amount of the tetracarboxylic dianhydride or derivative thereof represented by the above formula (2) is preferably 10 mol% or more, preferably 20 mol%, based on 1 mol of the total tetracarboxylic acid derivative component to be reacted with the diamine component. The above is more preferable.

<Method for producing polyimide precursor>
Polyamic acid, which is one of polyimide precursors, can be produced by the following method. Specifically, a tetracarboxylic acid derivative component containing a tetracarboxylic dianhydride and the diamine component are mixed in the presence of an organic solvent at −20 to 150° C., preferably 0 to 50° C., for 30 minutes to 24 hours. Preferably, it can be synthesized by reacting (polycondensation reaction) for 1 to 12 hours.
Specific examples of the organic solvent used in the above reaction include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, 1,3-dimethyl-2-imidazolidinone can be mentioned. Further, when the solvent solubility of the polymer is high, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, Ethylene glycol monopropyl ether, diethylene glycol monomethyl ether, or diethylene glycol monoethyl ether can be used. These may be used in combination of two or more.

The reaction can be carried out at any concentration, preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The initial stage of the reaction can be carried out at a high concentration, and then the solvent can be added. In the reaction, the ratio of the total number of moles of the diamine component to the total number of moles of the tetracarboxylic acid derivative component is preferably 0.8 to 1.2. Similar to a normal polycondensation reaction, the closer this molar ratio is to 1.0, the greater the molecular weight of the polyamic acid produced.

The polyamic acid obtained in the above reaction can be recovered by precipitating the polyamic acid by injecting the reaction solution into a poor solvent while stirring well. Further, a purified polyamic acid powder can be obtained by performing precipitation several times, washing with a poor solvent, and drying at room temperature or by heating. Poor solvents include, but are not limited to, water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.

A polyamic acid ester, which is one of the polyimide precursors, can be obtained by (1) a method of esterifying the polyamic acid, (2) a method of reacting a tetracarboxylic acid derivative component containing a tetracarboxylic acid diester dichloride with a diamine component, ( 3) It can be produced by a known method such as a method of polycondensing a tetracarboxylic acid derivative component including a tetracarboxylic acid diester with a diamine.

The above-mentioned polyamic acid and polyamic acid ester may be a terminal-modified polymer obtained by using an appropriate terminal blocking agent together with the tetracarboxylic acid derivative component and the diamine component as described above when producing them. .
Terminal blockers include, for example, acetic anhydride, maleic anhydride, nadic anhydride, phthalic anhydride, itaconic anhydride, cyclohexanedicarboxylic anhydride, 3-hydroxyphthalic anhydride, trimellitic anhydride, 3-( 3-trimethoxysilyl)propyl)-3,4-dihydrofuran-2,5-dione, 4,5,6,7-tetrafluoroisobenzofuran-1,3-dione, 4-ethynylphthalic anhydride, etc. acid monoanhydride; di-tert-butyl dicarbonate, dicarbonic acid diester compounds such as diallyl dicarbonate; acryloyl chloride, methacryloyl chloride, chlorocarbonyl compounds such as nicotinic acid chloride; aniline, 2-aminophenol, 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, monoamine compounds such as n-heptylamine and n-octylamine; isocyanates having unsaturated bonds such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate, 2-acryloyloxyethyl isocyanate and 2-methacryloyloxyethyl isocyanate and isothiocyanate compounds such as ethyl isothiocyanate and allyl isothiocyanate.
The proportion of the terminal blocking agent used is preferably 40 mol parts or less, more preferably 30 mol parts or less, with respect to a total of 100 mol parts of the diamine component used.

<Method for producing polyimide>
The polyimide used in the present invention can be produced by imidizing the above polyimide precursor by a known method.
In polyimide, the ring closure rate (also referred to as imidization rate) of the functional groups of the polyamic acid or polyamic acid ester does not necessarily need to be 100%, and can be arbitrarily adjusted according to the application and purpose.

As a method of imidizing the polyamic acid or polyamic acid ester to obtain a polyimide, thermal imidization is performed by heating the solution of the polyamic acid or polyamic acid ester as it is, or a catalyst (eg, catalyzed imidization by adding a basic catalyst such as pyridine, an acid anhydride such as acetic anhydride).

<Polymer Solution Viscosity/Molecular Weight>
The polyamic acid, polyamic acid ester and polyimide used in the present invention preferably have a solution viscosity of, for example, 10 to 1000 mPa s when the concentration is 10 to 15% by mass, from the viewpoint of workability. , is not particularly limited. The solution viscosity (mPa s) of the polymer is a polymer having a concentration of 10 to 15 mass% prepared using a good solvent for the polymer (eg, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.). It is a value measured at 25° C. for a solution using an E-type rotational viscometer.

The polystyrene equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of the polyamic acid, polyamic acid ester and polyimide is preferably 1,000 to 500,000, more preferably 2,000. ~500,000. In addition, the molecular weight distribution (Mw/Mn) represented by the ratio of Mw to the polystyrene equivalent number average molecular weight (Mn) measured by GPC is preferably 15 or less, more preferably 10 or less. With such a molecular weight range, it is possible to ensure good liquid crystal orientation of the liquid crystal display element.

<Liquid crystal aligning agent>
The liquid crystal aligning agent of this invention is used in order to produce a liquid crystal aligning film, and takes the form of a coating liquid from a viewpoint of forming a uniform thin film. Also in the liquid crystal aligning agent of the present invention, it is preferable that the liquid crystal aligning agent is a coating liquid containing the above-described polymer component and a solvent.
The content (concentration) of the polymer component contained in the liquid crystal aligning agent of the present invention can be appropriately changed by setting the thickness of the coating film to be formed. 1% by mass or more is preferable from the point of view, and 10% by mass or less is preferable from the point of storage stability of the solution.

The solvent contained in the liquid crystal aligning agent is not particularly limited as long as it uniformly dissolves the polymer component. Specific examples include N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethylsulfoxide and γ-butyrolactone. , γ-valerolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, N-(n-propyl)-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(tert-butyl)-2-pyrrolidone, N-(n-pentyl )-2-pyrrolidone, N-methoxypropyl-2-pyrrolidone, N-ethoxyethyl-2-pyrrolidone, N-methoxybutyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone (these are collectively referred to as "good solvents" Also called) and the like. Among them, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide and γ-butyrolactone are preferred. The content of the good solvent is preferably 20 to 99% by mass, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass of the total solvent contained in the liquid crystal aligning agent.

In addition, the solvent contained in the liquid crystal aligning agent is a mixed solvent in which a solvent (also referred to as a poor solvent) that improves the coatability and the surface smoothness of the coating film when applying the liquid crystal aligning agent is used in addition to the above solvent. is preferred. Specific examples of the poor solvent used in combination are shown below, but are not limited thereto.

For example, diisopropyl ether, diisobutyl ether, diisobutylcarbinol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether , 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene Glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2- Propanol, 2-(2-butoxyethoxy)-1-propanol, propylene glycol monomethyl ether acetate, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate tart, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy) ethyl acetate, diethylene glycol acetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, 3- Methyl methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, diisobutyl ketone (2 , 6-dimethyl-4-heptanone) and the like. The content of the poor solvent is preferably 1 to 80% by mass, more preferably 10 to 80% by mass, particularly preferably 20 to 70% by mass, of the total solvent contained in the liquid crystal aligning agent. The type and content of the poor solvent are appropriately selected according to the liquid crystal aligning agent coating device, coating conditions, coating environment, and the like.

Among them, diisobutyl carbinol, propylene glycol monobutyl ether, propylene glycol diacetate, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether, ethylene Glycol monobutyl ether acetate or diisobutyl ketone are preferred.

Preferred solvent combinations of a good solvent and a poor solvent include N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone and ethylene glycol monobutyl ether, N-methyl-2- Pyrrolidone, γ-butyrolactone and propylene glycol monobutyl ether, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and diisobutyl ketone, N-methyl-2-pyrrolidone and γ-butyrolactone and propylene glycol monobutyl ether and diisopropyl ether, N-methyl-2-pyrrolidone and Examples include γ-butyrolactone, propylene glycol monobutyl ether and diisobutyl carbinol, N-methyl-2-pyrrolidone, γ-butyrolactone and dipropylene glycol dimethyl ether, N-methyl-2-pyrrolidone, propylene glycol monobutyl ether and dipropylene glycol dimethyl ether. be able to.

The liquid crystal aligning agent of the present invention may additionally contain components (hereinafter also referred to as additive components) other than the polymer component and the solvent. Examples of such additive components include compounds for increasing the strength of the liquid crystal alignment film (hereinafter also referred to as cross-linking compounds), adhesion between the liquid crystal alignment film and the substrate, and adhesion between the liquid crystal alignment film and the sealing agent. Adhesion aids for increasing the dielectric constant and electrical resistance of the liquid crystal alignment film, dielectrics and conductive substances.

Examples of the crosslinkable compound include a crosslinkable compound (c-1) having at least one substituent selected from an epoxy group, an oxetanyl group, an oxazoline structure, a cyclocarbonate group, a blocked isocyanate group, a hydroxy group and an alkoxy group. , and at least one crosslinkable compound selected from the group consisting of crosslinkable compounds (c-2) having a polymerizable unsaturated group.
Preferred specific examples of the crosslinkable compounds (c-1) and (c-2) include the following compounds. Examples of epoxy group-containing compounds include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, and 1,6-hexane. Diol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, Epicoat 828 (manufactured by Mitsubishi Chemical Corporation), etc. Bisphenol A type epoxy resin, bisphenol F type epoxy resin such as Epicoat 807 (manufactured by Mitsubishi Chemical Corporation), hydrogenated bisphenol A type epoxy resin such as YX-8000 (manufactured by Mitsubishi Chemical Corporation), YX6954BH30 (manufactured by Mitsubishi Chemical Corporation) and the like biphenyl skeleton-containing epoxy resins, phenol novolac type epoxy resins such as EPPN-201 (manufactured by Nippon Kayaku Co., Ltd.), (o, m, p-) cresol novolac type epoxy resins such as EOCN-102S (manufactured by Nippon Kayaku Co., Ltd.), tetrakis(glycidyloxymethyl)methane, N,N,N',N'-tetraglycidyl-1,4-phenylenediamine, N,N,N',N'-tetraglycidyl-2,2'-dimethyl-4. 4'-diaminobiphenyl, 2,2-bis[4-(N,N-diglycidyl-4-aminophenoxy)phenyl]propane, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane compounds in which a tertiary nitrogen atom is bound to an aromatic carbon atom such as; 1,3-diaminocyclohexane, N,N,N',N'-tetraglycidyl-1,4-diaminocyclohexane, bis(N,N-diglycidyl-4-aminocyclohexyl)methane, bis(N,N-diglycidyl- 2-methyl-4-aminocyclohexyl)methane, bis(N,N-diglycidyl-3-methyl-4-aminocyclohexyl)methane, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,4 -bis(N,N-diglycidylaminomethyl)cyclohexane, 1,3-bis(N,N-diglycidylaminomethyl)benzene, 1,4-bis(N,N-diglycidylaminomethyl) Tertiary nitrogen such as lysidylaminomethyl)benzene, 1,3,5-tris(N,N-diglycidylaminomethyl)cyclohexane, 1,3,5-tris(N,N-diglycidylaminomethyl)benzene Compounds whose atoms are bonded to aliphatic carbon atoms, isocyanurate compounds such as triglycidyl isocyanurate such as TEPIC (manufactured by Nissan Chemical Industries, Ltd.), compounds described in paragraph [0037] of JP-A-10-338880, and WO2017 / compounds described in No. 170483;
As compounds having an oxetanyl group, 1,4-bis{[(3-ethyl-3-oxetanyl)methoxy]methyl}benzene (aron oxetane OXT-121 (XDO)), di[2-(3-oxetanyl)butyl] Ether (aron oxetane OXT-221 (DOX)), 1,4-bis[(3-ethyloxetan-3-yl)methoxy]benzene (HQOX), 1,3-bis[(3-ethyloxetan-3-yl ) methoxy]benzene (RSOX), 1,2-bis[(3-ethyloxetan-3-yl)methoxy]benzene (CTOX), two described in paragraphs [0170] to [0175] of WO2011/132751 Compounds having the above oxetanyl group, etc.;
Compounds having an oxazoline structure include compounds such as 2,2'-bis(2-oxazoline) and 2,2'-bis(4-methyl-2-oxazoline), and Epocross (trade name, manufactured by Nippon Shokubai Co., Ltd.). Polymers and oligomers having an oxazoline group, such as compounds described in paragraph [0115] of Japanese Patent Application Laid-Open No. 2007-286597;
As compounds having a cyclocarbonate group, N,N,N',N'-tetra[(2-oxo-1,3-dioxolan-4-yl)methyl]-4,4'-diaminodiphenylmethane, N,N' ,-Di[(2-oxo-1,3-dioxolan-4-yl)methyl]-1,3-phenylenediamine and paragraphs [0025] to [0030] and [0032] of WO2011/155577 compounds of;
Examples of compounds having a blocked isocyanate group include Coronate AP Stable M, Coronate 2503, 2515, 2507, 2513, 2555, Millionate MS-50 (manufactured by Tosoh Corporation), Takenate B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, B-882N (manufactured by Mitsui Chemicals, Inc.), two pieces described in paragraphs [0046] to [0047] of Japanese Patent Application Laid-Open No. 2014-224978 compounds having the above protected isocyanate groups, compounds having three or more protected isocyanate groups described in paragraphs [0119] to [0120] of WO2015/141598;
N,N,N',N'-tetrakis(2-hydroxyethyl)adipamide, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)propane as compounds having a hydroxy group and/or an alkoxy group , 2,2-bis(4-hydroxy-3,5-dimethoxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)-1,1,1,3,3, 3-Hexafluoropropane, WO2015/072554, compounds described in paragraph [0058] of JP-A-2016-118753, compounds described in JP-A-2016-200798, compounds described in WO2010/074269 compounds, etc.;
As crosslinkable compounds having a polymerizable unsaturated group, glycerin mono(meth)acrylate, glycerin di(meth)acrylate (1,2-,1,3-body mixture), glycerin tris(meth)acrylate, glycerol 1,3 - diglycerolate di(meth)acrylate, pentaerythritol tri(meth)acrylate, diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, pentaethylene glycol mono(meth)acrylate ) acrylate, hexaethylene glycol mono(meth)acrylate and the like.

The above compounds are examples of crosslinkable compounds, and are not limited to these. For example, components other than those described above disclosed on pages 53 [0105] to 55 [0116] of WO2015/060357 may be used. Moreover, you may combine two or more types of crosslinkable compounds.

When using a crosslinkable compound, the content of the crosslinkable compound in the liquid crystal aligning agent is preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the polymer component contained in the liquid crystal aligning agent. , more preferably 1 to 15 parts by mass.

Examples of the adhesion aid include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldiethoxymethylsilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N -(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N -ethoxycarbonyl-3-aminopropyltrimethoxysilane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-triethoxysilylpropyltriethylenetriamine, N-trimethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl -1,4,7-triazadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diaza nonyl acetate, N-benzyl-3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane , N-bis(oxyethylene)-3-aminopropyltrimethoxysilane, N-bis(oxyethylene)-3-aminopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4- epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p -styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane Silane couplings such as silane, tris-(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane ing agents.
When using an adhesion aid, the content of the adhesion aid in the liquid crystal aligning agent is preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the polymer component contained in the liquid crystal aligning agent, and more It is preferably 0.1 to 20 parts by mass.

(Liquid crystal alignment film)
The liquid crystal aligning film of the present invention is formed using the liquid crystal aligning agent of the present invention.
The manufacturing method of the liquid crystal aligning film of the present invention includes, for example, applying the liquid crystal aligning agent to a substrate and irradiating a film obtained by baking the substrate with radiation.
A preferred embodiment of the method for producing a liquid crystal alignment film of the present invention includes, for example, the step of applying the liquid crystal alignment agent to the substrate (step (1)), and the step of baking the applied liquid crystal alignment agent (step (2)). and a method for producing a liquid crystal alignment film, which optionally includes a step (step (3)) of subjecting the film obtained in step (2) to orientation treatment.

<Step (1)>
The substrate to which the liquid crystal aligning agent used in the present invention is applied is not particularly limited as long as it is a highly transparent substrate, and a glass substrate, a silicon nitride substrate, a plastic substrate such as an acrylic substrate, a polycarbonate substrate, or the like can also be used. In that case, it is preferable to use a substrate on which an ITO (Indium Tin Oxide) electrode for driving the liquid crystal is formed, in terms of process simplification. In addition, in a reflective liquid crystal display element, if only one substrate is used, an opaque material such as a silicon wafer can be used, and in this case, a light-reflecting material such as aluminum can be used for the electrodes.

Screen printing, offset printing, flexographic printing, inkjet method, spray method, etc., can be used as methods for applying the liquid crystal aligning agent to the substrate and forming a film. Among them, the coating method and the film-forming method by the inkjet method can be preferably used.

<Step (2)>
A process (2) is a process of baking the liquid crystal aligning agent apply|coated on the board|substrate, and forming a film|membrane. After the liquid crystal aligning agent is applied onto the substrate, a heating means such as a hot plate, thermal circulation oven or IR (infrared) oven is used to evaporate the solvent or heat the amic acid or amic acid ester in the polymer. imidization can be performed. The drying and baking steps after applying the liquid crystal aligning agent of the present invention can be performed at any desired temperature and time, and may be performed multiple times. The temperature for evaporating the solvent of the liquid crystal aligning agent can be, for example, 40 to 180°C. From the viewpoint of shortening the process, it may be carried out at 40 to 150°C. The firing time is not particularly limited, but may be 1 to 10 minutes or 1 to 5 minutes. When the amic acid or amic acid ester in the polymer is thermally imidized, a step of calcination at a temperature range of 150 to 300° C. or 150 to 250° C. can be performed after the step of evaporating the solvent. The firing time is not particularly limited, but may be 5 to 40 minutes or 5 to 30 minutes.
The thickness of the film after baking is preferably 5 to 300 nm, more preferably 10 to 200 nm, because if it is too thin, the reliability of the liquid crystal display element may be lowered.

<Step (3)>
Step (3) is a step of subjecting the film obtained in step (2) to orientation treatment. That is, in a vertical alignment type liquid crystal display element such as a VA mode or a PSA mode, the formed coating film can be used as a liquid crystal alignment film as it is, but the coating film may be subjected to an alignment treatment. The orientation treatment described here means a treatment for imparting orientation anisotropy in the horizontal direction. As the alignment treatment method for the liquid crystal alignment film, a rubbing treatment method may be used, but a photo-alignment treatment method is preferable. As a photo-alignment treatment method, the surface of the film-like material is irradiated with radiation so as to give an alignment direction in a certain direction, and in some cases, heat treatment is preferably performed at a temperature of 150 to 250 ° C. to align the liquid crystal. a method of imparting properties (also referred to as liquid crystal alignment ability). Although the type of radiation is not particularly limited, ultraviolet rays, visible rays, electron beams, etc. can be used. When using ultraviolet rays or visible light, a polarizer (also called a polarizing plate) is used to obtain polarized light ( hereinafter referred to as polarized light) is preferably used. The wavelength of ultraviolet rays and visible rays is not particularly limited because it is important to use wavelengths at which the photosensitive sites in the polymer react, but ultraviolet rays and visible rays in the range of 100 nm to 500 nm are preferable, and particularly preferably, It is polarized ultraviolet rays of 200 to 400 nm.

The irradiation dose of the radiation is preferably 1 to 10,000 mJ/cm ² . Among them, 100 to 5,000 mJ/cm ² is preferable. Moreover, when irradiating with radiation, in order to improve liquid crystal orientation, irradiation may be performed while heating. Although the temperature for heating is not particularly limited, it is preferably 50 to 250.degree. The liquid crystal alignment film thus produced can stably orient liquid crystal molecules in a fixed direction.
Furthermore, the liquid crystal alignment film obtained by the above method may be subjected to contact treatment using a solvent, and further heat treatment may be performed after the contact treatment.

The solvent used in the contact treatment is not particularly limited as long as it dissolves the decomposition products produced by irradiation with radiation. Specific examples include water, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, 1-methoxy-2-propanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, methyl lactate, diacetone alcohol, 3- methyl methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate and the like. Among them, water, 2-propanol, 1-methoxy-2-propanol and ethyl lactate are preferable from the viewpoint of versatility and solvent safety. More preferred are water, 1-methoxy-2-propanol or ethyl lactate. Solvents may be used singly or in combination of two or more.

The above contact treatment includes immersion treatment and spray treatment (also called spray treatment). The treatment time in these treatments is preferably 10 seconds to 1 hour from the viewpoint of efficiently dissolving the decomposition products produced by irradiation with radiation. Among them, it is preferable to perform the immersion treatment for 1 to 30 minutes. The contact treatment may be performed by cooling or heating, and the preferred temperature of the solvent used in the contact treatment is 10 to 80°C. Among them, 20 to 50°C is preferable. In addition, from the viewpoint of solubility of the decomposed product, ultrasonic treatment or the like may be performed as necessary.

After the contact treatment, it is preferable to perform rinsing (also called rinsing) with a low-boiling solvent such as water, methanol, ethanol, 2-propanol, acetone, or methyl ethyl ketone, or baking. At that time, either one of rinsing and baking may be performed, or both may be performed. The firing temperature is preferably 150 to 300°C. Among them, 180 to 250°C is preferable. More preferred is 200-230°C. Also, the baking time is preferably 10 seconds to 30 minutes. Among them, 1 to 10 minutes is preferable.
The heat treatment of the radiation-irradiated coating film is preferably carried out at 50 to 300° C. for 1 to 30 minutes, more preferably 120 to 250° C. for 1 to 30 minutes.

(liquid crystal display element)
The liquid crystal display element of the present invention has the liquid crystal alignment film of the present invention.
From the viewpoint of obtaining good horizontal uniaxial alignment, the liquid crystal alignment film of the present invention is suitable as a liquid crystal alignment film for a liquid crystal display element of a horizontal electric field system such as an IPS system or an FFS system, and in particular, a liquid crystal display of the FFS system. It is useful as a liquid crystal alignment film for devices.
The liquid crystal display element is produced by obtaining a substrate with a liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention, producing a liquid crystal cell by a known method, and encapsulating the liquid crystal in the liquid crystal cell. can be done. Specifically, the following two methods are mentioned.

In the first method, first, two substrates are arranged facing each other with a gap (cell gap) so that the respective liquid crystal alignment films face each other. Next, the peripheral portions of the two substrates are bonded together using a sealant, and the liquid crystal composition is injected and filled into the cells partitioned by the substrate surfaces and the sealant to bring it into contact with the film surface, and then the injection hole is opened. Seal.

The second method is a technique called the ODF (One Drop Fill) method. On either one of the two substrates on which the liquid crystal alignment film is formed, an ultraviolet light-curing sealant is applied so as to create a compartment for enclosing the liquid crystal, and on the surface of the liquid crystal alignment film in the compartment , the amount of liquid crystal composition corresponding to the cell volume is dropped at regular intervals. After that, the other substrate is attached under vacuum so that the liquid crystal alignment films face each other, and the liquid crystal composition is spread over the entire surface of the substrate and brought into contact with the film surface. Next, a method of obtaining a liquid crystal display element by irradiating ultraviolet light through a photomask so that the entire surface of the substrate or the liquid crystal alignment film is not exposed to light, performing temporary curing, and further curing the sealant by heat treatment. is.

In either method of the first method and the second method, the liquid crystal composition used is further heated to a temperature at which it assumes an isotropic phase, and then slowly cooled to room temperature, so that the flow orientation at the time of filling the liquid crystal should be removed.
When the coating film is subjected to the rubbing treatment, the two substrates are arranged opposite to each other so that the rubbing directions of the respective coating films are at a predetermined angle, for example, orthogonal or antiparallel. Similarly, when the optical alignment treatment is performed, the alignment directions are arranged to face each other at a predetermined angle, for example, perpendicular or antiparallel.
As the sealant, for example, an epoxy resin or the like containing a curing agent and aluminum oxide spheres as spacers can be used. Liquid crystals include nematic liquid crystals and smectic liquid crystals, among which nematic liquid crystals are preferred.
Specific examples of compounds constituting the nematic liquid crystal include Schiff base liquid crystal compounds, azoxy liquid crystal compounds, biphenyl liquid crystal compounds, phenylcyclohexane liquid crystal compounds, ester liquid crystal compounds, terphenyl liquid crystal compounds, biphenylcyclohexane liquid crystal compounds, Examples include pyrimidine-based liquid crystal compounds, dioxane-based liquid crystal compounds, bicyclooctane-based liquid crystal compounds, and cubane-based liquid crystal compounds.

Either a positive-type liquid crystal composition or a negative-type liquid crystal composition may be used as the liquid-crystal composition, but the negative-type liquid crystal composition is preferable because the transmittance during driving can be increased.
Typical commercial products of positive liquid crystal compositions include ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019 or MLC-7081 manufactured by Merck, PA-1492 manufactured by DIC, and the like. is mentioned.
Typical commercial products of negative liquid crystal compositions include MLC-6608, MLC-6609, MLC-6610, MLC-6882, MLC-6886, MLC-7026, MLC-7026-000 and MLC-7026 manufactured by Merck. -100, or MLC-7029.

Next, install the polarizing plate. Specifically, a pair of polarizing plates are attached to the surfaces of the two substrates opposite to the liquid crystal layer. Examples of the polarizing plate include a polarizing plate in which a polarizing film called "H film" in which iodine is absorbed while stretching orientation of polyvinyl alcohol is sandwiched between cellulose acetate protective films, or a polarizing plate composed of the H film itself. .

The present invention will be described in more detail with examples below, but the present invention is not limited to these. The abbreviations of the compounds and the methods for measuring each property are as follows.

(diamine)

(tetracarboxylic dianhydride)

(Diimide diester compound)

(Additive)

(solvent)
NMP: N-methyl-2-pyrrolidone BCS: ethylene glycol monobutyl ether

<Measurement of viscosity>
The viscosity of the 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 cone rotor TE-1 (1°34', R24) at a temperature of 25°C. bottom.

<Measurement of molecular weight>
The molecular weight of the polymer is determined using a room temperature gel permeation chromatography (GPC) device (GPC-101) (manufactured by Showa Denko) and a column (KD-803, KD-805 in series) (manufactured by Showa Denko). was measured as
Column temperature: 50°C
Eluent: N,N-dimethylformamide (as additives, lithium bromide monohydrate (LiBr.H ₂ O) at 30 mmol/L (liter), phosphoric acid/anhydrous crystals (o-phosphoric acid) at 30 mmol/L (liter) L, tetrahydrofuran (THF) is 10 mL/L)
Flow rate: 1.0 ml/min Standard sample for creating a calibration curve: TSK standard polyethylene oxide (molecular weight; 12,000, 4,000 and 1,000) (manufactured by Polymer Laboratories).

<Synthesis of Monomer>
DI-1 to DI-4 are novel compounds that have not been published in literature, etc., and their synthesis methods are described in detail below.

The products described in Monomer Synthesis Examples 1 to 4 below were identified by ¹ H-NMR analysis (analysis conditions are as follows).
Apparatus: NMR System 400 NB (400 MHz) manufactured by Varian
Measurement solvent: DMSO-d ₆
Reference substance: tetramethylsilane (TMS) (δ0.0 ppm for ¹ H)

(Monomer Synthesis Example 1 Synthesis of DI-1)

<Synthesis of DI-1-1>
Acetic acid (AcOH, 489 g), CA-1 (61.1 g, 312 mmol), and ammonium acetate (AcNH ₄ , 24.0 g, 312 mmol) were charged into a 2 L four-necked flask, and refluxed under a nitrogen atmosphere for about 2 days. reacted. After completion of the reaction, pure water (1500 g) was added to the reaction solution and stirred, the resulting precipitate was filtered off, the filtered product was washed with pure water and methanol, and dried to obtain DI-1-1 ( Yield: 51.9 g, 267 mmol, yield: 86%, properties: white crystals).

<Synthesis of DI-1>
To a 1 L four-necked flask, N,N-dimethylacetamide (DMAc, 260 g), DI-1-1 (26.0 g, 134 mmol), 4-dimethylaminopyridine (DMAP, 1.64 g, 13.4 mmol), and Triethylamine (Et ₃ N, 34.9 g, 345 mmol) was charged, and ethyl chloroformate (32.0 g, 295 mmol) was added dropwise under ice cooling conditions in a nitrogen atmosphere. After the dropwise addition, the reaction temperature was changed to room temperature (25° C.) and the reaction was allowed to proceed for 15 hours to eliminate the raw material (slurry solution). The slurry solution was filtered, and the filtrate was washed with an excess amount of methylene chloride and dried to obtain DI-1 (yield: 11.0 g, 32.5 mmol, yield: 24%, properties: white pink crystals).
¹ H-NMR (400 MHz, DMSO-d ₆ ): δ (ppm) = 4.37 (q, 4H, J = 7.2 Hz), 3.52 (s, 4H), 1.30 (t, 6H, J=7.2Hz)

(Monomer Synthesis Example 2 Synthesis of DI-2)

<Synthesis of DI-2>
N,N-dimethylacetamide (250 g), DI-1-1 (25.0 g, 129 mmol), and 4-dimethylaminopyridine (1.58 g, 12.9 mmol) were charged into a 2 L four-necked flask, and a nitrogen atmosphere was placed. Di-tert-butyl dicarbonate (Boc ₂ O, 61.9 g, 284 mmol) was added dropwise under room temperature (25° C.) conditions. After the dropwise addition, the reaction was allowed to proceed for 14 hours at room temperature to eliminate the raw material. After completion of the reaction, 2-propanol (750 g) was added to the reaction solution and stirred, and the resulting precipitate was filtered off and washed with 2-propanol to obtain DI-2 (yield: 48.1 g, 122 mmol , yield: 95%, properties: white crystals).
¹ H-NMR (400 MHz, DMSO-d ₆ ): δ (ppm) = 3.50 (s, 4H), 1.52 (s, 18H)

(Monomer Synthesis Example 3 Synthesis of DI-3)

<Synthesis of DI-3>
DI-3 was obtained by carrying out the above scheme in the same manner as in Monomer Synthesis Example 1 and Monomer Synthesis Example 2 (yield: 20.6 g, 48.7 mmol, yield : 83%, properties: white crystals).
¹ H-NMR (400 MHz, DMSO-d ₆ ): δ (ppm) = 3.30-3.01 (m, 4H), 2.05-2.03 (m, 4H), 1.50-1. 49 (m, 18H)

(Monomer Synthesis Example 3 Synthesis of DI-4)

<Synthesis of DI-4-1>
Acetic acid (245 g), CA-4 (14.0 g, 46.3 mmol), and ammonium acetate (21.5 g, 278 mmol) were charged into a 300 mL four-necked flask and reacted under reflux conditions in a nitrogen atmosphere for about 20 hours. . After completion of the reaction, pure water (150 g) was added to the reaction solution and stirred, the resulting precipitate was filtered off, the filtered product was washed with pure water and methanol, and dried to obtain DI-4-1 ( Yield: 6.98 g, 23.2 mmol, yield: 50%, properties: white crystals).

<Synthesis of DI-4>
Tetrahydrofuran (125 g), DI-4-1 (6.0 g, 20 mmol), and 4-dimethylaminopyridine (0.024 g, 0.2 mmol) were charged into a 200 mL four-necked flask and placed in a nitrogen atmosphere at room temperature (25°C). Di-tert-butyl dicarbonate (9.6 g, 44 mmol) was added dropwise under these conditions. After dropping, the mixture was reacted at 40° C. for 16 hours. After completion of the reaction, hexane (150 g) was added to the reaction solution and stirred, and the resulting precipitate was filtered off and washed with ethyl acetate (85 g) to obtain DI-4 (yield: 4.37 g, 8 .73 mmol, yield: 44%, properties: white crystals).
¹ H-NMR (400 MHz, DMSO-d ₆ ): δ (ppm) = 3.01 (s, 2H), 2.72 (s, 2H), 2.62 (s, 2H), 2.60 (s , 2H), 1.99 (s, 2H), 1.52 (d, 1H, J = 13.0 Hz), 1.48 (d, 18H, J = 3.2 Hz), 1.30 (d, 1H , J = 11.0 Hz), 1.10 (d, 1H, J = 11.0 Hz), 0.79 (d, 1H, J = 12.8 Hz).

<Synthesis of polymer>
(Synthesis example 1)
DA-1 (0.357 g, 3.30 mmol), DA-2 (0.806 g, 3.30 mmol), DA-3 (0.705 g, 2.20 mmol), DA-4 (0.877 g, 2.20 mmol), and NMP (30.4 g) were added and dissolved with stirring at room temperature. Then, CA-1 (2.34 g, 10.4 mmol) was added, NMP was added so that the solid content concentration was 12% by mass, and the mixture was stirred at 40° C. for 24 hours to form a polyamic acid solution (PAA- R1) (viscosity: 388 mPa·s) was obtained. This polyamic acid had a number average molecular weight of 11,244 and a weight average molecular weight of 30,370.

(Synthesis example 2)
DA-1 (0.357 g, 3.30 mmol), DA-2 (0.806 g, 3.30 mmol), DA-3 (0.705 g, 2.20 mmol), DA-4 (0.877 g, 2.20 mmol), and NMP (30.9 g) were added and dissolved with stirring at room temperature. After that, CA-1 (1.85 g, 8.25 mmol) and CA-2 (0.431 g, 2.20 mmol) were added, NMP was further added so that the solid content concentration was 12% by mass, and the temperature was 40 ° C. for 24 hours to obtain a polyamic acid solution (PAA-R2) (viscosity: 349 mPa·s). This polyamic acid had a number average molecular weight of 12,175 and a weight average molecular weight of 30,201.

(Synthesis Example 3)
DA-1 (0.324 g, 3.00 mmol), DA-2 (0.733 g, 3.00 mmol), DA-3 (0.641 g, 2.00 mmol), DA-4 (0.797 g, 2.00 mmol), and NMP (30.8 g) were added and dissolved with stirring at room temperature. DI-1 (0.677 g, 2.00 mmol) was then added and dissolved by stirring at 60° C. for 5 hours. Then, cool to 40 ° C., add CA-1 (1.78 g, 7.95 mmol), further add NMP so that the solid content concentration is 12% by mass, stir at 40 ° C. for 24 hours, A polymer solution (PAA-A1) (viscosity: 227 mPa·s) was obtained. This polymer had a number average molecular weight of 10,861 and a weight average molecular weight of 26,472.
When ¹ H-NMR measurement of the polymer obtained above was performed, a peak derived from an ethyl carbamate group, which was not observed in the polymers of Synthesis Examples 1 and 2, and a peak of 11.00 ppm were found near 1.29 ppm. A new amide peak was confirmed to occur at ~8.00 ppm, suggesting that the group represented by formula (1A) derived from DI-1 was introduced.

(Synthesis Example 4)
DA-1 (0.324 g, 3.00 mmol), DA-2 (0.733 g, 3.00 mmol), DA-3 (0.641 g, 2.00 mmol), DA-4 (0.797 g, 2.00 mmol), and NMP (30.8 g) were added and dissolved with stirring at room temperature. DI-2 (0.789 g, 2.00 mmol) was then added and dissolved by stirring at 60° C. for 5 hours. Then, cool to 40 ° C., add CA-1 (1.78 g, 7.95 mmol), further add NMP so that the solid content concentration is 12% by mass, stir at 40 ° C. for 24 hours, A polymer solution (PAA-A2) (viscosity: 225 mPa·s) was obtained. This polymer had a number average molecular weight of 10,531 and a weight average molecular weight of 26,987.
In the ¹ H-NMR measurement of the polymer obtained above, a peak 1 derived from the t-Bu carbamate group of DA-4 used in the polymers of Synthesis Example 1 and Synthesis Example 2 was found near 1.33 ppm. A peak derived from a t-Bu group different from .42 ppm and a new amide peak occurring at 11.00 to 8.00 ppm were confirmed, so the group represented by the formula (1A) derived from DI-2 It is considered that it has been introduced.

(Synthesis Example 5)
DA-5 (6.38 g, 32.0 mmol), DA-6 (1.22 g, 8.00 mmol) and NMP (109 g) were added to a 200 mL four-necked flask equipped with a stirrer and nitrogen inlet tube, Dissolved by stirring at room temperature. Then, CA-3 (11.3 g, 38.3 mmol) is added, NMP is added so that the solid content concentration is 12% by mass, and the mixture is stirred at room temperature for 24 hours to form a polyamic acid solution (PAA-B1). (viscosity: 384 mPa·s).

<Synthesis Example 6>
DA-1 (0.324 g, 3.00 mmol), DA-2 (0.733 g, 3.00 mmol), DA-3 (0.641 g, 2.00 mmol), DA-4 (0.797 g, 2.00 mmol), and NMP (30.8 g) were added and dissolved with stirring at room temperature. DI-3 (0.634 g, 1.50 mmol) was then added and dissolved by stirring at 60° C. for 5 hours. Then, cool to 40 ° C., add CA-1 (1.79 g, 8.00 mmol), further add NMP so that the solid content concentration is 12% by mass, stir at 40 ° C. for 24 hours, A polymer solution (PAA-A3) (viscosity: 56.7 mPa·s) was obtained. This polymer had a number average molecular weight of 6,432 and a weight average molecular weight of 13,826.
In the ¹ H-NMR measurement of the polymer obtained above, a peak 1 derived from the t-Bu carbamate group of DA-4 used in the polymers of Synthesis Example 1 and Synthesis Example 2 was found near 1.47 ppm. A peak derived from a t-Bu group different from .42 ppm and a new amide peak at 11.00 to 8.00 ppm were confirmed, so the group represented by the formula (1A) derived from DI-3 It is considered that it has been introduced.

<Synthesis Example 7>
DA-1 (0.324 g, 3.00 mmol), DA-2 (0.733 g, 3.00 mmol), DA-3 (0.641 g, 2.00 mmol), DA-4 (0.797 g, 2.00 mmol), and NMP (30.8 g) were added and dissolved with stirring at room temperature. DI-4 (0.751 g, 1.50 mmol) was then added and dissolved by stirring at 60° C. for 5 hours. Then, cool to 40 ° C., add CA-1 (1.79 g, 8.00 mmol), further add NMP so that the solid content concentration is 12% by mass, stir at 40 ° C. for 24 hours, A polymer solution (PAA-A4) (viscosity: 32.7 mPa·s) was obtained. This polymer had a number average molecular weight of 4,504 and a weight average molecular weight of 9,731.
In the ¹ H-NMR measurement of the polymer obtained above, a peak 1 derived from the t-Bu carbamate group of DA-4 used in the polymers of Synthesis Example 1 and Synthesis Example 2 was found near 1.40 ppm. A peak derived from a t-Bu group different from .42 ppm and a new amide peak occurring at 11.00 to 8.00 ppm were confirmed, so the group represented by the formula (1A) derived from DI-4 It is considered that it has been introduced.

<Preparation of liquid crystal aligning agent>
(Example 1)
NMP (5.67 g) and BCS (6.00 g) were added to the polymer solution PAA-A1 (8.33 g) obtained in Synthesis Example 3 and stirred at room temperature for 2 hours to obtain a liquid crystal aligning agent (V- 1) was obtained.

(Example 2)
A liquid crystal aligning agent (V-2) was obtained in the same manner as in Example 1, except that the polymer solution used was changed from PAA-A1 to PAA-A2.

(Example 3)
To the polymer solution PAA-A3 (10.00 g) obtained in Synthesis Example 6, NMP (14.00 g) and BCS (6.00 g) were added and stirred at room temperature for 2 hours to obtain a liquid crystal aligning agent (V- 3) was obtained.

(Example 4)
To the polymer solution PAA-A4 (10.00 g) obtained in Synthesis Example 7, NMP (14.00 g) and BCS (6.00 g) were added and stirred at room temperature for 2 hours to obtain a liquid crystal aligning agent (V- 4) was obtained.

(Example 5)
To the polymer solution PAA-A2 (1.88 g) obtained in Synthesis Example 4, the polyamic acid solution PAA-B1 (4.39 g) obtained in Synthesis Example 5, NMP (3.80 g), BCS (4. 80 g), an NMP 10% by mass diluted solution of AD-1 (0.376 g) and an NMP 1% by mass diluted solution of AD-2 (0.752 g) were added, stirred at room temperature for 2 hours, and a liquid crystal aligning agent (V-5 ).

(Comparative Example 1) to (Comparative Example 2)
Liquid crystal aligning agents (RV-1) to (RV-2) were prepared in the same manner as in Example 5, except that the polymer used was changed from PAA-A1 to polyamic acid solutions PAA-R1 to PAA-R2. ).

Table 2 shows the specifications of the liquid crystal aligning agents obtained in Examples 1-5 and Comparative Examples 1-2. The numbers in parentheses for the polymer components represent the ratio (parts by mass) of each polymer component with respect to the total 100 parts by mass of the polymer components.

Using the liquid crystal aligning agent obtained above, an FFS-driven liquid crystal cell was produced according to the procedure shown below, and various evaluations were performed.

<Configuration of FFS-driven liquid crystal cell>
A liquid crystal cell having the structure of an FFS mode liquid crystal display element was produced.
First, a substrate with electrodes was prepared. A glass substrate having a rectangular shape of 30 mm×35 mm and a thickness of 0.7 mm was used as the substrate. An ITO electrode having a solid pattern is formed as a first layer on the substrate to form a common electrode. A SiN (silicon nitride) film formed by a CVD (chemical vapor deposition) method is formed as a second layer on the common electrode of the first layer. The SiN film of the second layer has a film thickness of 300 nm and functions as an interlayer insulating film. On the SiN film of the second layer, a comb-shaped pixel electrode formed by patterning an ITO film is arranged as a third layer, and two pixels of a first pixel and a second pixel are formed. The size of each pixel is 10 mm long and 5 mm wide. The electrode-attached substrate has a structure in which the common electrode of the first layer and the pixel electrode of the third layer are insulated by the SiN film of the second layer.
The pixel electrode of the third layer has a comb-like shape in which a central portion is bent at an internal angle of 160° and a plurality of electrode lines with a width of 3 μm are arranged in parallel at intervals of 6 μm. A pixel is formed by a plurality of electrode lines, and has a first region and a second region bordering on a line connecting bent portions.
Next, the liquid crystal aligning agents (V-1) to (V-5) and (RV-1) to (RV-2) obtained in Examples 1 to 5 and Comparative Examples 1 and 2 were used with a pore size of 1.0 μm. After filtering with a filter, the substrate with the electrode (hereinafter referred to as the electrode substrate) and the glass substrate (hereinafter referred to as the counter substrate) having a columnar spacer with a height of 4 μm and having an ITO film formed on the back surface. , was applied by a spin coating method. After drying on a hot plate at 80° C. for 2 minutes, baking was performed in a hot air circulating oven at 230° C. for 20 minutes to form a coating film with a thickness of 100 nm. The coating film surface was subjected to alignment treatment by irradiating polarized ultraviolet rays through a 254 nm bandpass filter and a polarizer to obtain a substrate with a liquid crystal alignment film. The irradiation dose is shown in Table 3 below. The liquid crystal alignment film formed on the electrode substrate is subjected to an alignment treatment so that the direction of equally dividing the internal angle of the bent portion of the pixel and the alignment direction of the liquid crystal are orthogonal to each other. The liquid crystal alignment film is subjected to an alignment treatment so that the alignment direction of the liquid crystal on the electrode substrate and the alignment direction of the liquid crystal on the counter substrate are aligned when the liquid crystal cell is produced. The above two substrates are set as a set, a sealant (XN-1500T manufactured by Mitsui Chemicals, Inc.) is printed on the substrate with a dispenser, and another substrate is set so that the alignment direction of each liquid crystal alignment film is 0 °. I glued them together so that they would face each other. After that, the laminated substrates were pressure-bonded and heated in a hot air circulating oven at 150° C. for 60 minutes to cure the sealant, thereby producing an empty cell. Liquid crystal PA-1492 (manufactured by DIC) was injected into this empty cell by a vacuum injection method, and the injection port was sealed to obtain an FFS-driven liquid crystal cell. After that, the obtained liquid crystal cell was heated at 120° C. for 1 hour and left to stand overnight before being used for evaluation.

<Evaluation of in-plane uniformity of contrast>
Variation in the twist angle of the liquid crystal display element was evaluated using AxoStep manufactured by AXOMETRICS. The liquid crystal cell produced above was placed on a measurement stage, and the distribution of Circular Retardance in the pixel plane was measured with no voltage applied to calculate 3σ, which is three times the standard deviation σ. It can be said that the smaller the 3σ value, the better the in-plane uniformity. As evaluation criteria, the 3σ value was "excellent" when it was 1.10 or less, "good" when it was greater than 1.10 and 1.30 or less, and "poor" when it was greater than 1.30. .
Table 3 shows the evaluation results of the liquid crystal display elements using the liquid crystal aligning agents of the above Examples and Comparative Examples.

<Evaluation of stability of liquid crystal alignment>
This evaluation evaluates afterimages (also referred to as AC afterimages) caused by deterioration of the alignment performance of the liquid crystal alignment film during long-term AC driving.
An AC voltage of ±4.2 V at a frequency of 60 Hz was applied to the FFS-driven liquid crystal cell produced above for 120 hours in a constant temperature environment of 60°C. After that, the pixel electrode and the common electrode of the liquid crystal cell were short-circuited, and left at room temperature (23° C.) for one day. With respect to the liquid crystal cell subjected to the above treatment, the deviation between the alignment direction of the liquid crystal in the first region of the pixel and the alignment direction of the liquid crystal in the second region of the pixel was calculated as an angle when no voltage was applied. Specifically, a liquid crystal cell is placed between two polarizing plates whose polarization axes are orthogonal to each other, a backlight is turned on, and the liquid crystal cell is arranged so that the transmitted light intensity in the first region of the pixel is minimized. was adjusted, and then the rotation angle required when the liquid crystal cell was rotated so that the intensity of transmitted light in the second region of the pixel was minimized was obtained. It can be said that the smaller the rotation angle, the better the stability of the liquid crystal alignment.
As evaluation criteria, the value of the rotation angle is "excellent" if it is less than 0.100°, "good" if it is 0.100° or more and 0.200° or less, and is greater than 0.200°. The value was set as "poor".

Table 3 shows the evaluation results of the liquid crystal display elements using the liquid crystal aligning agents of the above Examples and Comparative Examples.

From the comparison between Examples 1 to 5 and Comparative Examples 1 to 2, the liquid crystal alignment films obtained from the liquid crystal alignment agents using the diimide diester compounds DI-1 to DI-4 are components that do not contain the diimide diester compound (B). It exhibited high in-plane uniformity and high stability of liquid crystal alignment compared to the liquid crystal alignment film obtained from the liquid crystal alignment agent.

The liquid crystal aligning film obtained from the liquid crystal aligning agent of the present invention can be suitably used for various liquid crystal display elements, typified by liquid crystal display elements of the IPS drive system and the FFS drive system. These display elements are not limited to liquid crystal displays intended for display, and are also useful in light control windows and optical shutters for controlling the transmission and blocking of light.

Claims

At least one compound selected from the group consisting of tetracarboxylic dianhydrides and derivatives thereof (excluding tetracarboxylic acid diimide diester compounds) and a diimide diester compound (B) represented by the following formula (1) Contains one or more polymers (A) selected from the group consisting of polyimide precursors obtained by polymerizing a tetracarboxylic acid derivative component and a diamine component, and polyimides that are imidized products of the polyimide precursors. death,
The polymer (A) has a group represented by the following formula (1A) derived from the diimide diester compound (B),
Liquid crystal aligning agent.

(X 1 represents a tetravalent organic group derived from an acyclic aliphatic tetracarboxylic dianhydride or an alicyclic tetracarboxylic dianhydride or a derivative thereof. Each R independently represents a carbon represents a monovalent organic group of numbers 1 to 5.)

(R represents a monovalent organic group having 1 to 5 carbon atoms. * represents a bond that binds to X 1. )
X 1 in the formula (1) is a tetracarboxylic acid dianhydride or derivative thereof having an acyclic aliphatic hydrocarbon group having 4 to 16 carbon atoms or an alicyclic aliphatic hydrocarbon group having 4 to 16 carbon atoms The liquid crystal aligning agent according to claim 1, which represents a tetravalent organic group derived from.
The liquid crystal aligning agent according to claim 1, wherein X 1 in the formula (1) represents any one of the following formulas (x-1) to (x-18).

(R 1 to R 4 each independently contain a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, or a fluorine atom. R 5 represents a monovalent organic group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 6 carbon atoms, an alkyloxycarbonyl group having 2 to 6 carbon atoms, or a phenyl group. and R6 each independently represent a hydrogen atom or a methyl group.
in formula (x-9)

represents a single bond or a double bond. )
The liquid crystal aligning agent according to claim 1, wherein the diimide diester compound (B) is at least one of compounds represented by the following formulas (b-1) to (b-9).
The liquid crystal aligning agent according to claim 1, wherein the tetracarboxylic acid derivative component contains a tetracarboxylic dianhydride represented by the following formula (2).

(X represents a structure selected from the group consisting of the following formulas (x-1) to (x-18) and (xr-1) to (xr-2).)

(R 1 to R 4 each independently contain a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, or a fluorine atom. R 5 represents a monovalent organic group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkoxyalkyl group having 2 to 6 carbon atoms, an alkyloxycarbonyl group having 2 to 6 carbon atoms, or a phenyl group. and R6 each independently represent a hydrogen atom or a methyl group.
in formula (x-9)

represents a single bond or a double bond.
j and k are integers of 0 or 1, and A 1 and A 2 each independently represent a single bond, —O—, —CO—, —COO—, a phenylene group, a sulfonyl group, or an amide group; show. A plurality of A 2 may be the same or different. *1 is a bond that bonds to one acid anhydride group, and *2 is a bond that bonds to the other acid anhydride group. )
The liquid crystal aligning agent according to claim 5, wherein the formula (x-1) is selected from the group consisting of the following formulas (x1-1) to (x1-6).

(*1 is a bond that bonds to one acid anhydride group, and *2 is a bond that bonds to the other acid anhydride group.)
The liquid crystal aligning agent according to claim 1, wherein the diamine component contains a diamine represented by the following formula (3).

(Ar 1 and Ar 1′ each represent a benzene ring, a biphenyl structure, or a naphthalene ring, and one or more hydrogen atoms on the benzene ring, the biphenyl structure, or the naphthalene ring are monovalent groups; optionally substituted, L 1 and L 1′ each represent a single bond, —O—, —C(=O)—, or —OC(=O)—, A is —CH 2 -, an alkylene group having 2 to 12 carbon atoms, or at least -O-, -C(=O)-O-, and -OC(=O)- between the carbon-carbon bonds of the alkylene group represents a divalent organic group into which any group is inserted.Any hydrogen atom of A may be substituted with a halogen atom.)
A method for producing a liquid crystal alignment film, comprising applying the liquid crystal alignment agent according to any one of claims 1 to 7 to a substrate, baking it, and irradiating the resulting film with radiation.
The method for producing a liquid crystal alignment film according to claim 8, wherein the firing temperature in the firing is 150 to 250°C.
A liquid crystal alignment film formed from the liquid crystal alignment agent according to any one of claims 1 to 7.
A liquid crystal display element comprising the liquid crystal alignment film according to claim 10.
The liquid crystal display element according to claim 11, which is an IPS drive system or an FFS drive system.
A diimide diester compound represented by the following formula (1).

(X 1 represents a tetravalent organic group derived from an acyclic aliphatic tetracarboxylic dianhydride or an alicyclic tetracarboxylic dianhydride or a derivative thereof. Each R independently represents a carbon represents a monovalent organic group of numbers 1 to 5.)
X 1 in the formula (1) is a tetracarboxylic acid dianhydride or derivative thereof having an acyclic aliphatic hydrocarbon group having 4 to 16 carbon atoms or an alicyclic aliphatic hydrocarbon group having 4 to 16 carbon atoms 14. The diimide diester compound according to claim 13, which represents a tetravalent organic group derived from.
The diimide diester compound according to claim 13, which is any one of compounds represented by the following formulas (b-1) to (b-6) and formula (b-8).
At least one compound selected from the group consisting of tetracarboxylic dianhydrides and derivatives thereof (excluding tetracarboxylic acid diimide diester compounds) and the diimide diester compound according to any one of claims 13 to 15. One or more selected from the group consisting of a polyimide precursor and a polyimide that is an imidized product of the polyimide precursor, obtained by polymerizing a tetracarboxylic acid derivative component and a diamine component containing
Having a group represented by the following formula (1A) derived from the diimide diester compound,
polymer.

(R represents a monovalent organic group having 1 to 5 carbon atoms. * represents a bond that binds to X 1. )