WO2024204521A1 - Liquid crystal aligning agent, liquid crystal alignment film, liquid crystal display element, and methods for manufacturing same - Google Patents

Abstract

The present invention provides: a liquid crystal aligning agent which makes it possible to achieve a liquid crystal alignment film that is excellent in terms of alignment uniformity of liquid crystals and resistance to an AC afterimage; a liquid crystal alignment film; a liquid crystal display element; and methods for manufacturing same.　Provided is a liquid crystal aligning agent which contains a polymer component (P) containing one or more polymers, and a compound (C) represented by formula (c), wherein the polymer component (P) contains at least one polymer (P) that is selected from the group consisting of polyimide precursors and polyimides that are imidized products of the polyimide precursors.　(c): (R_cO)_nP(=O)(OH)_2-nH (In formula (c), each R_c independently represents a monovalent organic group having 1 to 6 carbon atoms, and n is an integer of 1 or 2.)

Description

Liquid crystal alignment agent, liquid crystal alignment film, liquid crystal display element, and method for producing the same

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

A liquid crystal display element, for example, comprises a liquid crystal layer sandwiched between an element substrate and a color filter substrate, pixel electrodes and a common electrode that apply an electric field to the liquid crystal layer, a liquid crystal alignment film that controls the orientation of the liquid crystal molecules in the liquid crystal layer, and thin film transistors (TFTs) that switch the electrical signals supplied to the pixel electrodes. Known methods for driving liquid crystal molecules include vertical electric field methods such as the TN (Twisted Nematic) method and the VA (Vertical Alignment) method, and horizontal electric field methods such as the IPS (In-Plane Switching) method and the FFS (Fringe Field Switching) method.

Currently, the most widely used liquid crystal alignment film industrially is produced by rubbing the surface of a film made of a polymer, typically polyamic acid and/or polyimide formed by imidizing it, formed on an electrode substrate in one direction with a cloth such as cotton, nylon, or polyester, a so-called rubbing process (see, for example, Patent Document 1). The rubbing process is an industrially useful method that is simple and has excellent productivity. On the other hand, as liquid crystal display elements have become higher in performance, definition, and size, a photoalignment method that imparts liquid crystal alignment ability by irradiating polarized radiation has been known as an alternative alignment method to the rubbing process. As for photoalignment methods, methods that utilize photoisomerization reactions, photocrosslinking reactions, photodecomposition reactions, etc. have been proposed (see, for example, Patent Document 2 and Non-Patent Document 1).

WO2016/063834 publication Japanese Patent Publication No. 2011-107266

"Liquid crystal photoalignment film" Kidowaki, Ichimura, Functional Materials, November 1997, Vol. 17, No. 11, pp. 13-22

In recent years, large-screen, high-definition liquid crystal display elements have become mainstream, and small display terminals such as smartphones, tablet PCs, and car navigation systems have become more widespread, so the demand for high quality liquid crystal display elements is increasing more than ever before. In particular, as liquid crystal display elements become larger, a defect has occurred in which the twist angle of the liquid crystal within the liquid crystal display element surface varies slightly due to variations in the manufacturing process. Such variations cause the brightness of the liquid crystal display element to become non-uniform within the surface when the liquid crystal display element is set to display black, which leads to a decrease in the quality of the liquid crystal display element.
In addition, liquid crystal alignment films used in liquid crystal display elements, such as those of the IPS and FFS modes, require a high alignment control force to suppress image retention caused by long-term AC driving (hereinafter also referred to as AC image retention).

In view of the above, the object of the present invention is to provide a liquid crystal alignment agent capable of producing a liquid crystal alignment film having excellent alignment uniformity of liquid crystals and excellent resistance to AC image retention, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element.

As a result of intensive research into achieving the above object, the inventors have discovered that using a liquid crystal aligning agent containing a polymer component (P) containing one or more types of polymers and a phosphite ester compound is extremely effective in achieving the above object, and have completed the present invention.

The present invention includes the following aspects.
A liquid crystal aligning agent comprising a polymer component (P) containing one or more polymers, and a compound (C) represented by the following formula (c):
The liquid crystal aligning agent, wherein the polymer component (P) contains at least one polymer (P) selected from the group consisting of polyimide precursors and polyimides which are imidized products of the polyimide precursors.
(R _c O) _n P(=O)(OH) _2-n H (c)
(In formula (c), R _c 's each independently represent a monovalent organic group having 1 to 6 carbon atoms, and n is an integer of 1 or 2.)
Throughout this specification, the following terms and abbreviations have the following meanings: Halogen atom includes a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like.
In each case, * represents a bond, Boc represents a tert-butoxycarbonyl group, and Fmoc represents a 9-fluorenylmethoxycarbonyl group.

According to the present invention, it is possible to obtain a liquid crystal aligning agent capable of obtaining a liquid crystal alignment film having excellent alignment uniformity of liquid crystal and excellent resistance to AC afterimage, a liquid crystal alignment film obtained from the liquid crystal aligning agent, and a liquid crystal display element. In addition, the liquid crystal display element has high display quality with few display defects.
The mechanism by which the above-mentioned effects of the present invention are obtained is not necessarily clear, but is generally presumed to be as follows. It is presumed that the phosphorous acid compound acts on the polymer (P) described in the present invention to modify the film surface state, thereby improving the liquid crystal alignment. In addition, when two or more types of polymers are used, this tendency is particularly pronounced, and it is presumed that the phosphorous acid compound acts as a layer separation promoter, and components with good liquid crystal alignment are unevenly distributed on the film surface layer, improving the liquid crystal alignment, and the above-mentioned effects are obtained.

（式（Ｐ０）において、Ｘは４価の有機基を表し、Ｙは２価の有機基を表す。Ｒ及びＺはそれぞれ独立して、水素原子又は１価の有機基を表す。複数のＲ及びＺは、それぞれ独立して上記定義を有する。） <Polymer component (P)>
The polymer component (P) contained in the liquid crystal aligning agent of the present invention contains at least one polymer (P) selected from the group consisting of polyimide precursors and polyimides which are imidized products of the polyimide precursors. do.
The polymer (P) has, for example, one or more structural units, and is selected from the group consisting of a structural unit (p0) represented by the following formula (P0) and an imidized structural unit of the structural unit (p0): It may be an embodiment having at least one selected structural unit.

In formula (P0), X represents a tetravalent organic group, Y represents a divalent organic group, R and Z each independently represent a hydrogen atom or a monovalent organic group. and Z each independently have the above definition.

X in the above formula (P0) represents a tetravalent organic group, preferably a tetravalent tetracarboxylic acid residue. Here, the tetravalent tetracarboxylic acid residue may be, for example, a tetravalent organic group present between four carbonyl groups of a tetracarboxylic acid dianhydride or a derivative thereof (e.g., a tetracarboxylic acid, a tetracarboxylic acid dihalide, a tetracarboxylic acid dialkyl ester, or a tetracarboxylic acid dialkyl ester dihalide, etc.).
From the viewpoint of suitably obtaining the effects of the present invention, the above-mentioned X is preferably a tetravalent tetracarboxylic acid residue derived from an acyclic aliphatic tetracarboxylic acid dianhydride, an alicyclic tetracarboxylic acid dianhydride, an aromatic tetracarboxylic acid dianhydride, or a derivative thereof.
The tetracarboxylic dianhydride or derivative thereof which gives the above X is more preferably a tetracarboxylic dianhydride or derivative thereof having at least one partial structure selected from the group consisting of a benzene ring, a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring.
Here, the acyclic aliphatic tetracarboxylic acid dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups bonded to a chain hydrocarbon structure, but does not necessarily have to be composed of a chain hydrocarbon structure alone, and may have an alicyclic structure or an aromatic ring structure as a part thereof.
Alicyclic tetracarboxylic dianhydrides are acid dianhydrides 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 an aromatic ring. In addition, they do not necessarily have to be composed of an alicyclic structure alone, and may have a chain hydrocarbon structure or an aromatic ring structure as part of them.
An aromatic tetracarboxylic acid dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups, including at least one carboxy group bonded to an aromatic ring. However, it is not necessary for the aromatic tetracarboxylic acid dianhydride to be composed only of an aromatic ring structure, and it may have a chain hydrocarbon structure or an alicyclic structure as a part of the aromatic ring structure.

（式（Ｘａ１－１）～（Ｘａ１－３）において、Ｒ_１からＲ_１５はそれぞれ独立して、水素原子、ハロゲン原子、炭素数１～６のアルキル基、炭素数２～６のアルケニル基、炭素数２～６のアルキニル基、フッ素原子を含有する炭素数１～６の１価の有機基、又はフェニル基を表し、同一でも異なってもよい。＊は結合手を表す。）

（ｘ及びｙは、それぞれ独立に、単結合、エーテル、カルボニル、エステル、炭素数１～１０のアルカンジイル基、１，４－フェニレン、スルホニル又はアミド結合である。ｊ及びｋは、０又は１である。） In order to favorably obtain the effects of the present invention, X in the above formula (P0) may be a tetravalent organic group represented by any one of the following formulae (Xa1-1) to (Xa1-8), (X-1) to (X-17), or (X _b1 -a) to (X _b1 -c).

(In formulas (Xa1-1) to (Xa1-3), R ₁ to R ₁₅ each independently represent 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, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group, and may be the same or different. * represents a bond.)

(x and y each independently represent a single bond, an ether, a carbonyl, an ester, an alkanediyl group having 1 to 10 carbon atoms, 1,4-phenylene, a sulfonyl, or an amide bond; j and k each represent 0 or 1.)

Specific examples of the alkyl group having 1 to 6 carbon atoms in R ₁ to R ₁₅ in the above formulas (Xa1-1) to (Xa1-3) include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, etc. Specific examples of the alkenyl group having 2 to 6 carbon atoms in R ₁ to R ₁₅ include a vinyl group, a propenyl group, a butenyl group, etc., which may be linear or branched. Specific examples of the alkynyl group having 2 to 6 carbon atoms in R ₁ to R ₁₅ include an ethynyl group, a 1-propynyl group, a 2-propynyl group, a 1-butynyl group, a 2-butynyl group, a 3-butynyl group, etc. Examples of the fluorine atom-containing monovalent organic group having 1 to 6 carbon atoms in R ₁ to R ₁₅ include a fluoromethyl group, a trifluoromethyl group, a pentafluoroethyl group, and a pentafluoropropyl group.
From the viewpoint of improving the liquid crystal alignment property and the reliability of the liquid crystal display element, the X is preferably a tetravalent organic group represented by the above formula (Xa1-1). Furthermore, from the viewpoint of high photoreactivity, it is preferable that R ₁ to R ₄ are each independently a hydrogen atom or a methyl group, and at least one of R 1 to R ₄ is a methyl group _, and more preferably at least two of R ₁ to R ₄ are methyl groups. It is even more preferable that R ₁ and R ₄ are methyl groups, and R ₂ and R ₃ are hydrogen atoms. The above formula (Xa1-1) is preferably a tetravalent organic group selected from the group consisting of the following formulas (Xa1-1-1) to (Xa1-1-5).

From the viewpoint of suitably obtaining the effects of the present invention, the tetravalent organic groups represented by the above formulas (X _b1 -a) to (X _b1 -c) are more preferably tetravalent organic groups represented by any of the following formulas (X _b1 -1) to (X _b1 -21):

（式（３）及び（４）において、Ｒ_３、Ｒ_４、及びＲ_４’は、それぞれ独立して、ハロゲン原子、ヒドロキシ基、保護されてもよいアミノ基、チオール基、ニトロ基、リン酸基、又は炭素数１～２０の１価の有機基を表す。
　Ａ_４は、エステル結合、アミド結合、チオエステル結合、又は炭素数２～２０の２価の有機基を表す。但し、１，４－フェニレン基、該フェニレン基上の水素原子の１～４つがＲ_４、及びＲ_４’で置換されている２価の有機基、又はこれらの２価の有機基同士が連結した２価の有機基を除く。
　ａ３、ａ４、及びａ４’は、それぞれ独立して０～４の整数である。
　ａは、１～４の整数である。ｂ及びｃはそれぞれ独立して１～２の整数である。Ｒ_３、Ｒ_４、Ｒ_４’が複数存在する場合、Ｒ_３、Ｒ_４、及びＲ_４’の構造は同一でも異なってもよい。ａ３、ａ４、及びａ４’が複数存在する場合、それぞれ同一でも異なっていてもよい。＊は結合手を表す。） The divalent organic group for Y in the above formula (P0) is not particularly limited, but examples thereof include divalent organic groups represented by the following formulas (3) and (4).

In formulas (3) and (4), R ₃ , R ₄ , and R _4′ each independently represent a halogen atom, a hydroxy group, an optionally protected amino group, a thiol group, a nitro group, a phosphate group, or a monovalent organic group having 1 to 20 carbon atoms.
_A4 represents an ester bond, an amide bond, a thioester bond, or a divalent organic group having 2 to 20 carbon atoms, except for a 1,4-phenylene group, a divalent organic group in which 1 to 4 hydrogen atoms on the phenylene group are substituted with _R4 and R4 _' , or a divalent organic group in which these divalent organic groups are linked to each other.
a3, a4, and a4' each independently represents an integer of 0 to 4.
a is an integer of 1 to 4. b and c are each independently an integer of 1 to 2. When a plurality of R ₃ , R ₄ , and R _4' are present, the structures of R ₃ , R ₄ , and R _4' may be the same or different. When a plurality of a3, a4, and a4' are present, they may be the same or different. * represents a bond.

The monovalent organic group having 1 to 20 carbon atoms in R ₃ , R ₄ , and R _4′ in the above formulas (3) and (4) includes a monovalent hydrocarbon group having 1 to 20 carbon atoms, and any methylene group of the hydrocarbon group is -O-, -S-, -C(═O)-, -C(═O)-O-, -C(═O)-S-, -NR ³ - (wherein R ³ represents a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a tert-butoxycarbonyl group), -CO-NR ³ - (wherein R ³ represents a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a tert-butoxycarbonyl group), -Si(R ³ ) ₂ - (wherein R ³ represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms), -S(═O) ₂ - or the like (hereinafter, these groups are also referred to as heteroatom-containing group (A)), a monovalent hydrocarbon group or a monovalent group (A2) in which at least one hydrogen atom bonded to a carbon atom of the monovalent group A is substituted with a halogen atom, a hydroxy group, an alkoxy group, a nitro group, an amino group which may be protected by a protecting group, a mercapto group, a nitroso group, an alkylsilyl group, an alkoxysilyl group, a silanol group, a sulfino group, a phosphino group, a carboxy group, a cyano group, a sulfo group, an acyl group, or the like, and a monovalent group having a heterocycle. The number of carbon atoms in the group (A), the group (A2), and the monovalent group having a heterocycle is 1 to 20.
As the monovalent organic group having 1 to 20 carbon atoms for R ₃ , R ₄ , and R _4′, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, or a monovalent group in which any methylene group of the hydrocarbon group is replaced with the heteroatom-containing group (A) is even more preferred.
The optionally protected amino group includes --N(R) ₂ , where R represents a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a tert-butoxycarbonyl group.
The monovalent organic group having 1 to 20 carbon atoms in R ₃ , R ₄ , and R _4′ is preferably a methyl group, a methoxy group, a vinyl group, a halogen atom, a hydroxyl group, an amino group which may be protected by a protecting group, or a monovalent group in which at least one hydrogen atom of an alkyl group having 1 to 3 carbon atoms has been substituted with a halogen atom or an amino group which may be protected by a protecting group.

In the above formula (3), a is preferably an integer of 1 to 2. In the above formula (3), a3 is preferably an integer of 0 to 2, and when there are multiple a3s, they may be the same or different. In the above formula (4), a4 and a4' are each independently preferably an integer of 0 to 2, and when there are multiple a4s and multiple a4's, they may be the same or different.

The divalent organic group having 2 to 20 carbon atoms in A ₄ of the above formula (4) is a hydrocarbon group having 2 to 20 carbon atoms; any alkylene group contained in the hydrocarbon group may be -C(=O)-, -NR-, -C(=O)-O-, -Si(R ⁰ ) ₂ and a divalent organic group (4a) in which the carbon atom is replaced by at least one of -, -O-C(=O)- (provided that the divalent organic group (4a) has 2 to 20 carbon atoms); a divalent organic group (4b) in which -O- is inserted at at least one position between the terminal of a hydrocarbon group having 2 to 20 carbon atoms and between the carbon-carbon bonds of any alkylene groups contained in the hydrocarbon group; a divalent organic group (4c) in which -O- is inserted at at least one position between the carbon-carbon bonds of any alkylene groups contained in the divalent organic group (4a); and a divalent organic group (4d) having 2 to 20 carbon atoms and having a heterocycle.
R in the above -NR- represents a hydrogen atom, a monovalent hydrocarbon group having 1 to 5 carbon atoms, or a tert-butoxycarbonyl group. R ⁰ in the above -Si(R ⁰ ) ₂ - represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms.

Examples of the hydrocarbon group include a chain hydrocarbon group, an alicyclic hydrocarbon group, or a hydrocarbon group having an aromatic group (examples of the aromatic ring structure in the aromatic group include a benzene ring, a naphthalene ring, a biphenyl structure, an anthracene ring, etc.).
Specific examples of the chain hydrocarbon group include a divalent linear or branched hydrocarbon group having 1 to 20 carbon atoms not having a cyclic structure, and are preferably an alkylene group having 1 to 20 carbon atoms, an alkenylene group having 2 to 20 carbon atoms, or an alkynylene group having 2 to 20 carbon atoms.
Specific examples of the alicyclic hydrocarbon group include an alicyclic structure (for example, a cyclohexylene group or a bicyclohexylene group), or a hydrocarbon group having an alicyclic structure and a chain hydrocarbon structure.
Specific examples of the hydrocarbon group having an aromatic group include an aromatic group, a hydrocarbon group having an aromatic group and a chain hydrocarbon structure, and a hydrocarbon group having an aromatic group and an alicyclic structure.

The heterocyclic ring in the divalent organic group (4d) may be a piperidine ring, a piperazine ring, a morpholine ring, a pyrrolidine ring, a pyrrole ring, a furan ring, a thiophene ring, an imidazole ring, a pyrazole ring, an imide ring, an oxazole ring, an isoxazole ring, a thiazole ring, an isothiazole ring, a pyridine ring, a pyrimidine ring, a pyridazine ring, or a pyrazine ring, or a condensed ring containing these ring structures as part of its structure, and the hydrogen atoms on the ring may be substituted. Examples of the substituent include a halogen atom, a methyl group, or a methoxy group.

In order to obtain the effects of the present invention favorably, A ₄ in the above formula (4) is preferably a group "-L _{1 -AL 1'-} " or a divalent organic group having 2 to 20 carbon atoms and a heterocycle.
The total number of carbon atoms of L ₁ , L _{1 '} and A in the group "-L ₁ -AL _{1 '} -" satisfies 2 to 20.
_L1 and L1 _' each independently represent a single bond, -O-, -NR-, -C(=O)-NR-, -C(=O)-, or -O-C(=O)-, and R represents a hydrogen atom, a monovalent hydrocarbon group having 1 to 5 carbon atoms, or a tert-butoxycarbonyl group.
In terms of suitably obtaining the effects of the present invention, A in the group "-L ₁ -A-L _{1 '} -" is an alkylene group having 1 to 12 carbon atoms, -CH=CH-, -C≡C-, -CR ₀ ≡CR _{0 '} -C(=O)-O- (R ₀ and R _{0 '} each independently represent a hydrogen atom or a methyl group), or -O-, -NR-, -C(=O)-NR-, -C(=O)-NR-C(=O)-, -C(=O)-O-, -Si(R ^a ) ₂ A divalent organic group having at least one of - and -O-C(=O)- inserted therein, -O-Ar-O-, -O-C(=O)-Ar-C(=O)-O-, -C(=O)-O-Ar-O-C(=O)-, provided that when _L1 and L1 _' represent single bonds, A represents a group other than a methylene group.
R in the above -C(=O)-NR- and -C(=O)-NR-C(=O)- represents a hydrogen atom, a monovalent hydrocarbon group having 1 to 5 carbon atoms, or a tert-butoxycarbonyl group. R ^a in -Si(R ^a ) ₂ - represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 3 carbon atoms. Any hydrogen atom possessed by A may be substituted with a halogen atom.
In the above-mentioned -O-Ar-O-, -O-C(=O)-Ar-C(=O)-O-, and -C(=O)-O-Ar-O-C(=O)-, Ar represents a phenylene group or a biphenyl structure.

（式（ｄ_ＡＬ－６）において、ｍ１及びｍ２が０の場合、ｍ１、ｍ２及びｎの合計は、１～１２であり、ｍ１及びｍ２の少なくとも一つが０以外の整数の場合、ｍ１、ｍ２及びｎの合計は、２～１２である。式（ｄ_ＡＬ－８）において、ｍ１、ｍ２及びｎの合計は、３～１２である。式（ｄ_ＡＬ－１１）及び式（ｄ_ＡＬ－１２）、において、ｍ１、ｍ２及びｎの合計は、３～１２である。））

More preferred specific examples of the above formulae (3) and (4) include structures represented by the following formulae (d _AL -1) to (d _AL -12), (5-1) to (5-6), (z-1) to (z-7), (o2-1) to (o2-12), (h-1) to (h-13), and (Im-1) to (Im-6). In the structures represented by the following formulae (d _AL -1) to (d _AL -8), (5-1) to (5-6), (z-1) to (z-7), (o2-1) to (o2-12), and (h-1) to (h-13), the bonding positions of the benzene ring bonded to * are the 1,4-positions. In the following formula (d _AL -9), the bonding positions of all benzene rings are the 1,4-positions.

(In formula (d _AL -6), when m1 and m2 are 0, the sum of m1, m2 and n is 1 to 12, and when at least one of m1 and m2 is an integer other than 0, the sum of m1, m2 and n is 2 to 12. In formula (d _AL -8), the sum of m1, m2 and n is 3 to 12. In formula (d _AL -11) and formula (d _AL -12), the sum of m1, m2 and n is 3 to 12.)

In order to obtain high display quality even when the liquid crystal panel is used for a long time at high temperatures, a higher voltage holding ratio (hereinafter, voltage holding ratio is also referred to as VHR) than ever before may be required for the liquid crystal alignment film. From the viewpoint of obtaining a high VHR, the polymer (P) is preferably a polymer containing a structural unit having a divalent organic group selected from the group consisting of a divalent organic group having a urea bond; a divalent organic group having an amide bond; a divalent organic group having at least one nitrogen atom-containing structure selected from the group consisting of a nitrogen atom-containing heterocycle, a secondary amino group, and a tertiary amino group; and a divalent organic group having a carboxy group (collectively referred to as specific divalent organic group (b)).

An example of the divalent organic group having a urea bond is a divalent organic group represented by the above formula (4) in which _A4 in the above formula (4) has the group "-NH-C(=O)-NR-".
The divalent organic group having an amide bond includes a divalent organic group represented by the above formula (4) in which _A4 in the above formula (4) has an amide bond.
Examples of the divalent organic group having at least one nitrogen atom-containing structure selected from the group consisting of a nitrogen atom-containing heterocycle, a secondary amino group, and a tertiary amino group include 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, and those having the structures represented by the above formulae (z-1) to (z-7). and divalent organic groups obtained by removing two amino groups from a diamine selected from the group consisting of heterocycle-containing diamines such as diamine, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl-N-methylamine, N,N'-bis(4-aminophenyl)-benzidine, N,N'-bis(4-aminophenyl)-N,N'-dimethylbenzidine, or diamines having a diphenylamine structure such as N,N'-bis(4-aminophenyl)-N,N'-dimethyl-1,4-benzenediamine.
Examples of the divalent organic group having a carboxy group include divalent organic groups obtained by removing two amino groups from a diamine having a carboxy group, such as 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, 4,4'-diaminobiphenyl-3-carboxylic acid, 4,4'-diaminodiphenylmethane-3-carboxylic acid, 1,2-bis(4-aminophenyl)ethane-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)ethane-3,3'-dicarboxylic acid, and 4,4'-diaminodiphenylether-3,3'-dicarboxylic acid.

Furthermore, the divalent organic group of Y _a1 in the above formula (A1) may have a structure other than the divalent organic groups represented by the above formulas (3) and (4).
Other structures include a divalent organic group (3L) in which the bonding position of the benzene ring bonding to * in the above formula (3) is changed from 1,4-position to 2,5-position; a divalent organic group (4L) in which at least one bonding position of the benzene ring bonding to * in the above formula (4) is changed from 1,4-position to 2,5-position; or a divalent organic group obtained by removing two amino groups from the following diamines (these diamines are also collectively referred to as diamines (W)). In the above divalent organic groups (3L) and (4L), preferred aspects of R ₃ , R ₄ , R _4' , A ₄ , a3, a4, a4', a, b, and c are the same as those in the above formulas (3) to (4).

　Aromatic diamines having a naphthalene ring such as 1,2-bis(6-amino-2-naphthyloxy)ethane, 1,2-bis(6-amino-2-naphthyl)ethane, or 6-[2-(4-aminophenoxy)ethoxy]-2-naphthylamine, 4,4'-diaminoazobenzene, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 4,4' -Diaminobenzophenone, 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl-N-methylamine, 4-(2-(methylamino)ethyl)aniline, 4-(2-aminoethyl)aniline, 1-(4-aminophenyl) 1,3,3-trimethyl-1H-indan-5-amine, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-inden-6-amine, cholestanyloxy-3,5-diaminobenzene, cholestanyloxy-3,5-diaminobenzene, cholestanyloxy-2,4-diaminobenzene, cholestanyl 3,5-diaminobenzoate, cholestanyl 3,5-diaminobenzoate, lanostannyl 3,5-diaminobenzoate, and 3,6-bis(4-aminobenzoyloxy)cholestane. diamines having a siloxane bond such as 1,3-bis(3-aminopropyl)-tetramethyldisiloxane; metaxylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), diamines having two amino groups bonded to a group represented by any one of formulas (Y-1) to (Y-167) described in WO2018/117239, etc.

From the viewpoint of suitably obtaining the effects of the present invention, the polymer (P) preferably contains the structural unit (p0) and the imidized structural unit of the structural unit (p0) in an amount of 10 to 100 mol %, and more preferably 15 to 100 mol %, of the total structural units contained in the polymer (P).
In addition, the total here includes the case where either the structural unit (p0) or the imidized structural unit of the structural unit (p0) is 0 mol %. In the following, the total also includes the case where one or more of the structural unit elements are 0 mol %.

From the viewpoint of optimally obtaining the effects of the present invention, the polymer (P) preferably contains structural units having a divalent organic group represented by the above formulas (3) to (4) in an amount of 10 to 100 mol %, and more preferably 15 to 100 mol %, of all structural units contained in the polymer (P).

The monovalent organic groups for R and Z in the above formula (P0) include monovalent hydrocarbon groups having 1 to 20 carbon atoms, and monovalent groups A in which a methylene group of the hydrocarbon group is replaced by -O-, -S-, -CO-, -COO-, -COS-, -NR ³ -, -CO-NR ³ -, -Si(R ³ ) ₂ -, -SO ₂ - or the like (wherein R ³ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, and when there are a plurality of R ^3's , each R ³ may be the same or different. ), a monovalent group in which at least one hydrogen atom bonded to a carbon atom of the monovalent hydrocarbon group or the monovalent group A is substituted with a halogen atom, a hydroxy group, an alkoxy group, a nitro group, an amino group, a mercapto group, a nitroso group, an alkylsilyl group, an alkoxysilyl group, a silanol group, a sulfino group, a phosphino group, a carboxy group, a cyano group, a sulfo group, an acyl group, or the like, a monovalent group having a heterocycle, etc. As the monovalent organic group for R and Z in the above formula (1), an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, Boc, or Fmoc is preferable, an alkyl group having 1 to 3 carbon atoms is more preferable, and a methyl group is even more preferable.
From the viewpoint of suitably obtaining the effects of the present invention, R and Z are each independently preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom or a methyl group.

（式（Ａ１）において、Ｘ_ａ１は上記式（Ｘａ１－１）～（Ｘａ１－８）からなる群から選ばれる４価の有機基を表し、Ｙ_ａ１は２価の有機基を表す。上記式（Ａ１）中、Ｒ、及びＺは、上記式（Ｐ０）における場合と同義である。）

（式（Ｂ１）において、Ｘ_ｂ１は炭素数６～３０の芳香族基を有する４価の有機基を表し、Ｘ_ｂ１と結合するカルボニル炭素の少なくとも一つはＸ_ｂ１の芳香族基と結合する。Ｙ_ｂ１は２価の有機基を表す。上記式（Ｂ１）中、Ｒ、及びＺは、上記式（Ｐ０）における場合と同義である。） The polymer component (P) contained in the liquid crystal aligning agent of the present invention may be a polymer component containing two or more kinds of polymers and satisfying at least one of the following conditions (i) to (iii):
(i) A polymer component (P1) having one or more types of structural units and including two or more types of at least one polymer selected from the group consisting of a polyimide precursor (A) having a structural unit (a1) represented by the following formula (A1) and a polyimide which is an imidized product of the polyimide precursor:
(ii) A polymer component (P2) which is a polymer different from the polyimide precursor (A) and has one or more types of structural units and contains two or more types of polyimide precursors (B) having a structural unit (b1) represented by the following formula (B1):
(iii) A polymer component (P3) containing at least one polymer selected from the group consisting of the polyimide precursor (A) and a polyimide which is an imidization product of the polyimide precursor, and the polyimide precursor (B).

(In formula (A1), X _a1 represents a tetravalent organic group selected from the group consisting of formulas (Xa1-1) to (Xa1-8) above, and Y _a1 represents a divalent organic group. In formula (A1), R and Z have the same meanings as in formula (P0) above.)

(In formula (B1), X _b1 represents a tetravalent organic group having an aromatic group having 6 to 30 carbon atoms, and at least one of the carbonyl carbons bonded to X _b1 is bonded to the aromatic group of X _b1 . Y _b1 represents a divalent organic group. In formula (B1), R and Z are defined as in formula (P0).)

The polymer component (P) may be composed of a polymer having no acid-dissociable group. Here, the acid-dissociable group is a group having a bond that is cleaved by an acid, and a part or all of the acid-dissociable group is eliminated from the main chain of the polymer by cleavage of the bond.
Preferred examples of the acid-dissociable group include protecting groups that protect amino groups, hydroxy groups, etc. Examples of such protecting groups include carbamate-based protecting groups (specific examples include tert-butoxycarbonyl and 9-fluorenylmethyloxycarbonyl groups), and groups that form an acetal structure or a tertiary ether structure together with the protected oxygen atom.
A polymer having no acid-leaving group can be obtained, for example, by using a raw material component having no acid-leaving group (specific examples of raw materials having no acid-leaving group include a diamine having no acid-leaving group, a tetracarboxylic dianhydride or a derivative thereof having no acid-leaving group, and a terminal modifier that does not form an acid-leaving group).

<Polyimide precursor (A)>
The polymer components (P1) and (P3) contained in the liquid crystal alignment agent of the present invention contain one or more structural units and contain a polyimide precursor (A) having a structural unit (a1) represented by the above formula (A1). The polyimide precursor (A) may be one or more polymers. The polyimide precursor (A) may have one type of structural unit, or may have two or more different structural units, or may have three or more different structural units, or may have four or more different structural units.

The divalent organic group of Y _a1 in the above formula (A1) is not particularly limited, and examples thereof include divalent organic groups represented by the above formulas (3) to (4). The divalent organic group is introduced into the structural unit of the polyimide precursor (A), for example, by using a diamine having the above divalent organic group as a diamine component for obtaining the polyimide precursor (A).
From the viewpoint of suitably obtaining the effects of the present invention, at least one of the structural units constituting the polyimide precursor (A) preferably has a structure selected from the group consisting of divalent organic groups represented by the above formulas (3) to (4), and more preferably has a structure selected from the group consisting of divalent organic groups represented by the above formulas (3) to (4) in which * is bonded to a nitrogen atom derived from a diamine.
In order to preferably obtain the effects of the present invention, Y _a1 in the above formula (A1) is preferably a divalent organic group selected from the group consisting of the above formulas (3) and (4).

More preferred specific examples of the above formulae (3) and (4) are the same as the preferred embodiments of the above formulae (3) to (4) in the polymer (P). Among them, more preferred specific examples include structures represented by the above formulae (d _AL -1) to (d _AL -12), (5-1) to (5-6), (z-1) to (z-7), (o2-1) to (o2-12), (h-1) to (h-13), and (Im-1) to (Im-6). In the structures represented by the above formulae (d _AL -1) to (d _AL -8), (5-1) to (5-6), (z-1) to (z-7), (o2-1) to (o2-12), and (h-1) to (h-13), the bonding positions of the benzene ring bonded to * are the 1,4-positions. In the following formula (d _AL -9), the bonding positions of all benzene rings are 1,4-positions.

Furthermore, the divalent organic group of Y _a1 in the above formula (A1) may have a structure other than the divalent organic groups represented by the above formulas (3) and (4).
Other structures include a divalent organic group (3L) in which the bonding positions of the benzene ring bonding to * in the above formula (3) are changed from 1,4-positions to 2,5-positions, a divalent organic group (4L) in which at least one bonding position of the benzene ring bonding to * in the above formula (4) is changed from 1,4-positions to 2,5-positions, or a divalent organic group in which two amino groups have been removed from the above diamine (W), etc. In the above divalent organic groups (3L) and (4L), preferred aspects of R ₃ , R ₄ , R _4' , A ₄ , a3, a4, a4', a, b, and c are the same as those in the above formulas (3) to (4).

（式（Ａ２）において、Ｘ_ａ２は上記式（Ｘ－１）～（Ｘ－１７）のいずれかで表される４価の有機基、又は芳香族テトラカルボン酸二無水物に由来する４価の有機基を表し、Ｙ_ａ２は２価の有機基を表す。上記式（Ａ２）中、Ｒ、及びＺは、上記式（Ｐ０）における場合と同義である。） From the viewpoint of suitably obtaining the effects of the present invention, the polyimide precursor (A) may be a polyimide precursor having, in addition to the structural unit (a1) represented by the above formula (A1), a structural unit (a2) represented by the following formula (A2):

(In formula (A2), X _a2 represents a tetravalent organic group represented by any one of formulas (X-1) to (X-17) above, or a tetravalent organic group derived from an aromatic tetracarboxylic dianhydride, and Y _a2 represents a divalent organic group. In formula (A2), R and Z have the same meanings as in formula (P0).)

Specific examples of the divalent organic group of Y _a2 in the above formula (A2) include the structures exemplified for the divalent organic group of Y _a1 in the above formula (A1), including preferred embodiments.

The aromatic tetracarboxylic dianhydride is as defined above, including preferred embodiments. Preferred specific examples of the aromatic tetracarboxylic dianhydride include tetravalent organic groups represented by any one of the above formulae (X _b1 -a) to (X _b1 -c), and more preferably tetravalent organic groups represented by any one of the above formulae (X _b1 -1) to (X _b1 -21).

From the viewpoint of suitably obtaining the effects of the present invention, the polyimide precursor (A) preferably contains the structural unit (a1) and the imidized structural unit of the structural unit (a1) in an amount of 10 to 100 mol %, and more preferably 15 to 100 mol %, of the total structural units contained in the polyimide precursor (A).
From the viewpoint of suitably obtaining the effects of the present invention, the polyimide precursor (A) preferably contains structural units having a divalent organic group represented by the above formulas (3) to (4) in an amount of 10 to 100 mol %, more preferably 15 to 100 mol %, of all structural units contained in the polyimide precursor (A).
When the polyimide precursor (A) contains a structural unit other than the structural unit (a1) and/or the imidized structural unit of the repeating unit (a1), the sum of the structural unit (a1) and the imidized structural unit of the structural unit (a1) preferably accounts for 95 mol % or less, and more preferably 90 mol % or less, of all structural units contained in the polyimide precursor (A).

（式（Ｂ１）において、Ｘ_ｂ１は炭素数６～３０の芳香族基を有する４価の有機基を表し、Ｘ_ｂ１と結合するカルボニル炭素の少なくとも一つはＸ_ｂ１の芳香族基と結合する。Ｙ_ｂ１は２価の有機基を表す。上記式（Ｂ１）中、Ｒ、及びＺは、上記式（Ｐ０）における場合と同義である。） <Polyimide precursor (B)>
The polymer components (P2) and (P3) contained in the liquid crystal alignment agent of the present invention contain a polyimide precursor (B) which is a polymer different from the polyimide precursor (A), has one or more structural units, and has a structural unit (b1) represented by the following formula (B1). The polyimide precursor (B) may be one or more polymers. The polyimide precursor (B) may have one type of structural unit, or may have two or more different structural units, or may have three or more different structural units, or may have four or more different structural units.

(In formula (B1), X _b1 represents a tetravalent organic group having an aromatic group having 6 to 30 carbon atoms, and at least one of the carbonyl carbons bonded to X _b1 is bonded to the aromatic group of X _b1 . Y _b1 represents a divalent organic group. In formula (B1), R and Z are defined as in formula (P0).)

X _b1 in the above formula (B1) represents a tetravalent organic group having an aromatic group having 6 to 30 carbon atoms, and at least one of the carbonyl carbons bonded to X _b1 is bonded to the aromatic group of X _b1 . More preferably, it is a tetravalent organic group derived from an acid dianhydride obtained by intramolecular dehydration of four carboxy groups including at least one carboxy group bonded to an aromatic ring (benzene ring, naphthalene ring, etc.). However, it is not necessary for the group to be composed of only an aromatic ring structure, and it may have a chain hydrocarbon structure or an alicyclic structure as a part thereof.
A preferred specific example of X _b1 is a tetravalent organic group derived from an aromatic tetracarboxylic acid compound. X _b1 is preferably a tetravalent organic group represented by any one of the above formulas (X _b1 -a) to (X _b1 -c), more preferably a tetravalent organic group represented by any one of the above formulas (X _b1 -1) to (X _b1 -21), and even more preferably a tetravalent organic group represented by any one of the above formulas (X _b1 -1) to (X _b1 -13). Even more preferably, X b1 is a tetravalent organic group selected from the group consisting of the above formulas (X _b1 -1) to (X _b1 -7).

Examples of the divalent organic group in Y _b1 include the divalent organic groups exemplified for Y _a1 . From the viewpoint of reducing residual images caused by residual DC, the polyimide precursor (B) is preferably a polymer containing a structural unit having the specific divalent organic group (b).
From the viewpoint of reducing afterimages resulting from residual DC, the polyimide precursor (B) is preferably a polymer containing a structural unit in which Y _b1 is the specific divalent organic group (b) described above.

From the viewpoint of reducing afterimages derived from residual DC, the polyimide precursor (B) preferably contains structural units having the specific divalent organic group (b) (more preferably structural units having the specific divalent organic group bonded to a nitrogen atom derived from a diamine) in an amount of 1 mol % or more, preferably 5 mol % or more, more preferably 10 mol % or more, and even more preferably 20 mol % or more of all structural units contained in the polyimide precursor (B).
From the viewpoint of reducing an afterimage derived from residual DC, the polyimide precursor (B) preferably contains structural units in which Y _b1 is the specific divalent organic group (b) in an amount of 1 mol % or more, preferably 5 mol % or more, more preferably 10 mol % or more, and even more preferably 20 mol % or more of all structural units contained in the polyimide precursor (B).

（式（Ｂ２）において、Ｘ_ｂ２は非環式脂肪族テトラカルボン酸二無水物、又は脂環式テトラカルボン酸二無水物に由来する４価の有機基を表し、Ｙ_ｂ２は２価の有機基を表す。上記式（Ｂ２）中、Ｒ、及びＺは、上記式（Ｐ０）における場合と同義である。） From the viewpoint of suitably obtaining the effects of the present invention, the polyimide precursor (B) may be a polyimide precursor having, in addition to the structural unit (b1) represented by the above formula (B1), a structural unit (b2) represented by the following formula (B2):

(In formula (B2), X _b2 represents a tetravalent organic group derived from an acyclic aliphatic tetracarboxylic acid dianhydride or an alicyclic tetracarboxylic acid dianhydride, and Y _b2 represents a divalent organic group. In formula (B2), R and Z have the same meanings as in formula (P0).)

In the above formula (B2), the acyclic aliphatic tetracarboxylic acid dianhydride and the alicyclic tetracarboxylic acid dianhydride are defined as above.

From the viewpoint of suitably obtaining the effects of the present invention, X _b2 is preferably a tetravalent organic group represented by any one of the above formulas (X-1) to (X-17) or (Xa1-1) to (Xa1-8).

From the viewpoint of suitably obtaining the effects of the present invention, the polyimide precursor (B) preferably contains the structural unit (b1) and the imidized structural unit of the structural unit (b1) in an amount of 10 to 100 mol %, and more preferably 15 to 100 mol %, of the total structural units contained in the polyimide precursor (B).
In addition, when the polyimide precursor (B) contains a structural unit other than the structural unit (b1) and/or the imidized structural unit of the repeating unit (b1), the structural unit (b1) preferably accounts for 95 mol % or less, and more preferably 90 mol % or less, of all structural units contained in the polyimide precursor (B).
The polyimide precursor (B) preferably contains the structural unit (b2) in an amount of 5 mol % or more, more preferably 10 mol % or more, based on the total structural units contained in the polyimide precursor (B), and preferably contains the structural unit (b2) in an amount of 90 mol % or less, more preferably 85 mol % or less, based on the total structural units contained in the polyimide precursor (B).

In the polymer component (P), the mass ratio of the content of the first polyimide precursor to the content of the second polyimide precursor (content of the first polyimide precursor/content of the second polyimide precursor) is preferably 10/90 to 90/10, more preferably 20/80 to 90/10, and even more preferably 20/80 to 80/20.
From the viewpoint of reducing an afterimage caused by residual DC, the mass ratio of the content of the polyimide precursor (A) to the content of the polyimide precursor (B) (the content of the polyimide precursor (A)/the content of the polyimide precursor (B)) is preferably from 10/90 to 90/10, more preferably from 20/80 to 90/10, and even more preferably from 20/80 to 80/20.

<Methods for producing polymer (P), polyimide precursor (A), and polyimide precursor (B)>
The polymer (P) and the polyimide precursors (A) and (B) in the present invention can be synthesized by a known method such as that described in WO2013/157586.

Specifically, it is obtained by reacting (condensation polymerization) a tetracarboxylic acid derivative component containing a tetracarboxylic dianhydride with a diamine component in a solvent. There are no particular limitations on the solvent as long as it dissolves the resulting polymer.

For example, when synthesizing a polyimide precursor (A) having a repeating unit represented by the above formula (A1), a diamine having a structure of -NZ-Y _a1 -NZ- (Y _a1 and Z are defined the same as Y _a1 in formula (A1)) is used as the diamine component, and a tetracarboxylic acid dianhydride having a structure of the above formula (X _a1 ) (X _a1 is defined the same as X _a1 in formula (A1)) is used as the tetracarboxylic acid derivative component.

The ratio of the tetracarboxylic dianhydride and the diamine used in the synthesis reaction of the polyimide precursor is preferably such that the acid anhydride group of the tetracarboxylic dianhydride is 0.5 to 2 equivalents, more preferably 0.8 to 1.2 equivalents, per equivalent of the amino group of the diamine. As in the case of a normal polycondensation reaction, the closer the equivalent of the acid anhydride group of the tetracarboxylic dianhydride is to 1 equivalent, the higher the molecular weight of the polyimide precursor produced.
The reaction temperature in the synthesis reaction of the polyimide precursor is preferably −20 to 150° C., more preferably 0 to 100° C. The reaction time is preferably 0.1 to 24 hours, more preferably 0.5 to 12 hours.
The synthesis reaction of the polyimide precursor can be carried out at any concentration, but the concentration of the polyimide precursor in the reaction solution is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction can be carried out at a high concentration in the early stage, and then a solvent can be added.

Specific examples of the solvent used when reacting the diamine component with the tetracarboxylic acid derivative component include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, and 1,3-dimethyl-2-imidazolidinone. In addition, when the polymer has high solvent solubility, it is possible to use a solvent represented by the formula: methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or H ₃ C-CH(OH)-CH _{2 -O} -D ¹ (D ¹ represents an alkyl group having 1 to 3 carbon atoms), HO-CH ₂ -CH ₂ -O-D ² (D ² represents an alkyl group having 1 to 3 carbon atoms), or HO-CH ₂ -CH 2 -O-CH ₂ -CH ₂ -D ³ (D ³ represents an alkyl group having 1 to 4 carbon atoms). These solvents may be used alone or in combination.

Specific examples of the solvent represented by the above H ₃ C—CH(OH)—CH ₂ -O-D ¹ , HO-CH ₂ -CH ₂ -O-D ² , and HO-CH ₂ -CH ₂ -O-CH ₂ -CH ₂ -D ³ include propylene glycol monomethyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether.

<Polymer solution viscosity and molecular weight>
In the present invention, the polymer (P), the polyimide precursor (A), and the polyimide precursor (B) preferably have a solution viscosity of, for example, 10 to 1000 mPa·s when made into a solution of 10 to 15% by mass from the viewpoint of workability, but are not particularly limited thereto. The solution viscosity (mPa·s) of the polymer is a value measured at 25° C. using an E-type rotational viscometer for a polymer solution of 10 to 15% by mass prepared using a good solvent for the polymer (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

The weight average molecular weight (Mw) of the polymer (P), polyimide precursor (A), and polyimide precursor (B) measured by gel permeation chromatography (GPC) in terms of polystyrene is preferably 1,000 to 500,000, and more preferably 2,000 to 300,000. The molecular weight distribution (Mw/Mn), which is expressed as the ratio of Mw to the number average molecular weight (Mn) measured by GPC in terms of polystyrene, is preferably 15 or less, and more preferably 10 or less. From the viewpoint of optimally obtaining the effects of the present invention, it is preferable for the molecular weight to be within this range.

<End-capping agent>
In synthesizing the polymer (P), polyimide precursor (A), and polyimide precursor (B) in the present invention, a suitable end-capping agent may be used together with the above-mentioned tetracarboxylic acid derivative component and diamine component to form an end-capping type polymer. The end-capping type polymer has the effect of improving the film hardness of the liquid crystal alignment film obtained by coating and improving the adhesion property between the sealant and the liquid crystal alignment film.

Examples of the terminals of the polymer (P), polyimide precursor (A), and polyimide precursor (B) in the present invention include amino groups, carboxy groups, acid anhydride groups, and derivatives thereof. The amino groups, carboxy groups, and acid anhydride groups can be obtained by a normal condensation reaction, or by blocking the terminals with the following terminal blocking agents, and can be obtained in the same manner, for example, by using the following terminal blocking agents.

Examples of end-capping agents include acid monoanhydrides such as 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, and 4-ethynylphthalic anhydride; dicarbonate diester compounds such as di-tert-butyl dicarbonate and diallyl dicarbonate; chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride, and nicotinic acid chloride; aniline, 2-aminophenol, 3-aminophenol, Examples of the monoamine compounds include 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, n-heptylamine, and n-octylamine; monoisocyanate compounds such as 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 end-capping agent used is preferably 0.01 to 20 molar parts, and more preferably 0.01 to 10 molar parts, per 100 molar parts of the total diamine components used.

<Compound (C)>
The liquid crystal aligning agent of the present invention contains the compound (C) represented by the above formula (c). The compound (C) may be one type or two or more types of compounds.
Specific examples of the monovalent organic group for R _c in the above formula (c) include 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, a monovalent organic group containing a fluorine atom having 1 to 6 carbon atoms, or an aromatic group having 6 carbon atoms.
Specific examples of the alkyl group having 1 to 6 carbon atoms in the above R _c include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, and an n-pentyl group. Specific examples of the alkenyl group having 2 to 6 carbon atoms in the above R _c include a vinyl group, a propenyl group, and a butenyl group, which may be linear or branched. Specific examples of the alkynyl group having 2 to 6 carbon atoms in the above R _c include an ethynyl group, a 1-propynyl group, a 2-propynyl group, a 1-butynyl group, a 2-butynyl group, and a 3-butynyl group. Examples of the monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom in the above R _c include a fluoromethyl group, a trifluoromethyl group, a pentafluoroethyl group, and a pentafluoropropyl group. Examples of the aromatic group having 6 carbon atoms include a phenyl group which may be substituted with a halogen atom.
R _c is preferably an alkyl group having 1 to 6 carbon atoms, and more preferably an alkyl group having 1 to 4 carbon atoms.
More preferred specific examples of the compound (C) include methyl phosphite, ethyl phosphite, propyl phosphite, butyl phosphite, hexyl phosphite, phenyl phosphite; dimethyl phosphite, diethyl phosphite, dipropyl phosphite, dibutyl phosphite, dihexyl phosphite, diphenyl phosphite, and the like.

The total content of the compound (C) is preferably 0.1 mass % or more, more preferably 0.2 mass % or more, and even more preferably 0.3 mass % or more, when all components in the liquid crystal aligning agent are taken as 100 mass %.
In addition, the total content of the compound (C) is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less, from the viewpoint of suitably obtaining the effects of the present invention, when all components in the liquid crystal alignment agent are 100% by mass.
In addition, the ratio of the total mass of the components other than the (C) component of the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent is 99.9% by mass or less, more preferably 99.8% by mass or less, and even more preferably 99.7% by mass or less, when all components in the liquid crystal alignment agent are 100% by mass. Furthermore, the ratio of the total mass of the components other than the (C) component of the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent is preferably 90% by mass or more, when all components in the liquid crystal alignment agent are 100% by mass.

The liquid crystal alignment agent of the present invention contains an organic solvent. Specific examples of organic solvents include N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactamide, N,N-dimethylpropionamide, tetramethylurea, N,N-diethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethylsulfoxide, γ-butyrolactone, γ-valerolactone, 1,3-dimethyl-2-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, 3-methoxy-N ...propionamide, tetramethylurea, N,N-diethylpropionamide, tetramethylurea, N,N-diethylpropionamide, tetramethylurea, N,N-diethylpropionamide, tetramethylurea, N,N-diethylpropionamide, tetramethylurea, N,N-diethylpropionamide, tetramethylurea, N,N-diethylpropionamide, tetramethylurea, N Examples of the good solvent include N-propanamide, 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, and N-cyclohexyl-2-pyrrolidone (collectively referred to as "good solvents"). Among these, 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% by mass or more, and more preferably 30% by mass or more, assuming that the total components in the liquid crystal alignment agent are 100% by mass.

In addition, the organic solvent contained in the liquid crystal alignment agent is preferably a mixed solvent containing a solvent (also called a poor solvent) that improves the coatability and surface smoothness of the coating film when applying the liquid crystal alignment agent in addition to the above-mentioned solvent. The content of the poor solvent is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, when the total components in the liquid crystal alignment agent are taken as 100% by mass.
The total content of the good solvent and the poor solvent is preferably 99.9% by mass or less, more preferably 99.8% by mass or less, and even more preferably 99.7% by mass or less, when the total amount of all components in the liquid crystal alignment agent is 100% by mass.
The type and content of the poor solvent are appropriately selected depending on the coating device, coating conditions, coating environment, etc. of the liquid crystal alignment agent. Specific examples of the poor solvent are listed below, but are not limited thereto.

Diisopropyl ether, diisobutyl ether, diisobutyl carbinol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol 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 Examples of the ether acetate include propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether acetate, diethylene glycol monopropyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol diacetate, propylene glycol diacetate, n-butyl acetate, propylene glycol monoethyl ether acetate, cyclohexyl acetate, 4-methyl-2-pentyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, n-butyl lactate, isoamyl lactate, diethylene glycol monoethyl ether, and diisobutyl ketone (2,6-dimethyl-4-heptanone).

Among the poor solvents, 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, and diisobutyl ketone are preferred.

Preferred solvent combinations of good and poor solvents include N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether, N-methyl-2-pyrrolidone, 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-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone, N-ethyl-2-pyrrolidone and propylene glycol diacetate, and N,N-dimethyl lactamide and diisopropyl ether. isobutyl ketone, N-methyl-2-pyrrolidone and ethyl 3-ethoxypropionate, N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate, N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate, N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether, N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate and diethylene glycol monopropyl ether, N-methyl-2-pyrrolidone and ethylene glycol monobutyl ether acetate, N-ethyl-2-pyrrolidone and ethylene glycol monobutyl ether acetate Pyrrolidone and dipropylene glycol dimethyl ether, N,N-dimethyl lactamide and ethylene glycol monobutyl ether, N,N-dimethyl lactamide and propylene glycol diacetate, N-ethyl-2-pyrrolidone and diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone, diethylene glycol monoethyl ether and butyl cellosolve acetate, N-methyl-2-pyrrolidone, diethylene glycol monomethyl ether and butyl cellosolve acetate, N,N-dimethyl lactamide and diethylene glycol diethyl ether, N-methyl-2-pyrrolidone N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, N-ethyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, propylene glycol monobutyl ether, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, diisobutyl ketone, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, dipropylene glycol monomethyl ether, N-methyl N-ethyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and propylene glycol diacetate, N-ethyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and dipropylene glycol dimethyl ether, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and diisobutyl ketone, γ-butyrolactone, 4-hydroxy-4-methyl-2-pentanone, and propylene glycol diacetate, N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether, and diisobutyl ketone, N-methyl-2-pyrrolidone, γ-butyrolactone, propylene glycol monobutyl ether, and diisopropyl ether, N-methyl-2-pyrrolidone, 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, N-ethyl-2-pyrrolidone and propylene glycol monobutyl ether. propylene glycol monobutyl ether and dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone, diethylene glycol diethyl ether and dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and propylene glycol diacetate, N-ethyl-2-pyrrolidone, propylene glycol monobutyl ether and diisobutyl ketone, N-ethyl-2-pyrrolidone, γ-butyrolactone and diisobutyl ketone, N-ethyl-2-pyrrolidone, N,N-dimethyl lactamide and diisobutyl ketone, N-methyl Examples of such compounds include N-ethyl-2-pyrrolidone, ethylene glycol monobutyl ether, and ethylene glycol monobutyl ether acetate, γ-butyrolactone, ethylene glycol monobutyl ether acetate, and dipropylene glycol dimethyl ether, N-ethyl-2-pyrrolidone, ethylene glycol monobutyl ether acetate, and propylene glycol dimethyl ether, N-methyl-2-pyrrolidone, 4-methyl-2-pentyl acetate, and ethylene glycol monobutyl ether, and N-methyl-2-pyrrolidone, cyclohexanone, and propylene glycol monomethyl ether.

The solid content concentration in the liquid crystal alignment agent (the ratio of the total mass of the components other than the solvent of the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) is appropriately selected in consideration of viscosity, volatility, etc., and is preferably in the range of 1 to 10 mass%. From the viewpoint of forming a uniform and defect-free coating film, 1 mass% or more is preferable, and from the viewpoint of storage stability of the solution, 10 mass% or less is preferable. A particularly preferable solid content concentration is 2 to 8 mass%.
The range of the solid content may be appropriately selected depending on the method used when applying the liquid crystal alignment agent to the substrate. For example, when spin-coating is performed, it is particularly preferable that the solid content is 1.5 to 4.5% by mass. When using the printing method, it is particularly preferable that the solid content is 3 to 9% by mass, thereby making the solution viscosity 12 to 50 mPa·s. When using the inkjet method, it is particularly preferable that the solid content is 1 to 5% by mass, thereby making the solution viscosity 3 to 15 mPa·s. The temperature when preparing the liquid crystal alignment agent is preferably 10 to 50°C, more preferably 20 to 30°C.
The concentration of the polymer component in the liquid crystal alignment agent can be appropriately changed depending on the thickness of the coating film to be formed. From the viewpoint of forming a uniform and defect-free coating film, the concentration of the polymer component in the liquid crystal alignment agent (total concentration of polymers) is preferably 1% by mass or more, and from the viewpoint of storage stability of the solution, it is preferably 10% by mass or less. The particularly preferred polymer concentration is 2 to 8% by mass.
The content of the polymer component (P) in the liquid crystal alignment agent (the total amount of polymers constituting the polymer component (P)) is, from the viewpoint of suitably obtaining the effects of the present disclosure, preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably 50 parts by mass or more, relative to a total of 100 parts by mass of the polymer components contained in the liquid crystal alignment agent.
When the liquid crystal alignment agent contains other polymers described later, the content of the polymer component (P) is preferably 99.9 parts by mass or less, more preferably 99 parts by mass or less, per 100 parts by mass of the total of the polymers contained in the liquid crystal alignment agent.

The liquid crystal alignment agent of the present invention may contain other components as necessary. Examples of such components include other polymers than the polymer (P) and the polyimide precursors (A) and (B); at least one compound selected from the group consisting of crosslinkable compounds having at least one substituent selected from an epoxy group, an isocyanate group, an oxetanyl group, a cyclocarbonate group, a blocked isocyanate group, a hydroxyl group, and an alkoxy group (excluding the above compound (C)), and crosslinkable compounds having a polymerizable unsaturated group; functional silane compounds; metal chelate compounds; curing accelerators; surfactants; antioxidants; sensitizers; preservatives; compounds for adjusting the dielectric constant and electrical resistance of the liquid crystal alignment film; compounds for promoting imidization, and the like.

Specific examples of other polymers include polymers selected from the group consisting of polysiloxanes, polyesters, polyamides, polyureas, polyurethanes, polyorganosiloxanes, cellulose derivatives, polyacetals, polystyrene derivatives, poly(styrene-maleic anhydride) copolymers, poly(isobutylene-maleic anhydride) copolymers, poly(vinyl ether-maleic anhydride) copolymers, poly(styrene-phenylmaleimide) derivatives, and poly(meth)acrylates.

Specific examples of poly(styrene-maleic anhydride) copolymers include SMA1000, 2000, 3000 (Cray Valley) and GSM301 (Gifu Ceramics Manufacturing). Specific examples of poly(isobutylene-maleic anhydride) copolymers include ISOBAM-600 (Kuraray). Specific examples of poly(vinyl ether-maleic anhydride) copolymers include Gantrez AN-139 (methyl vinyl ether maleic anhydride resin, Ashland). The other polymers may be used alone or in combination of two or more. The content of the other polymers is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, relative to a total of 100 parts by mass of the polymers contained in the liquid crystal alignment agent. The content of the other polymers is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, relative to a total of 100 parts by mass of the polymers contained in the liquid crystal alignment agent.

Preferred specific examples of the above crosslinkable 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, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, bisphenol A type epoxy resins such as Epicoat 828 (manufactured by Mitsubishi Chemical Corporation), bisphenol F type epoxy resins such as Epicoat 807 (manufactured by Mitsubishi Chemical Corporation), hydrogenated bisphenol A type epoxy resins such as YX-8000 (manufactured by Mitsubishi Chemical Corporation), and biphenyls such as YX6954BH30 (manufactured by Mitsubishi Chemical Corporation). 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.), triglycidyl isocyanurates such as TEPIC (manufactured by Nissan Chemical Industries, Ltd.), alicyclic epoxy resins such as Celloxide 2021P (manufactured by Daicel Corporation), N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(2-methyl-2-propanediol), compounds containing a tertiary nitrogen atom, such as tetrakis(glycidyloxymethyl)methane, and compounds having two or more oxiranyl groups, such as tetrakis(N,N-diglycidylaminomethyl)cyclohexane or N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane; compounds having two or more oxetanyl groups, such as those described in paragraphs [0170] to [0175] of WO2011/132751; Compounds having a blocked isocyanate group, such as Bull M, Coronate 2503, 2515, 2507, 2513, 2555, Millionate MS-50 (all manufactured by Tosoh Corporation), Takenate B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, B-882N (all manufactured by Mitsui Chemicals, Inc.); 2,2'-bis(2-oxazoline), 2,2'-bis(4-methyl-2-oxazoline), 2, Compounds having an oxazoline group, such as 2'-bis(5-methyl-2-oxazoline), 1,2,4-tris(2-oxazolinyl)-benzene, and EPOCROS (manufactured by Nippon Shokubai Co., Ltd.); compounds having a cyclocarbonate group, such as those described in paragraphs [0025] to [0030] and [0032] of WO2011/155577; N,N,N',N'-tetrakis(2-hydroxyethyl)adipamide, 2,2-bis(4-hydroxy-3,5-di hydroxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethoxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)-1,1,1,3,3,3-hexafluoropropane, and other compounds having a hydroxy group or an alkoxy group; and compounds represented by glycerin mono(meth)acrylate, glycerin di(meth)acrylate (1,2-,1,3-mixture), glycerin tris(meth)acrylate, glycerin 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, and hexaethylene glycol mono(meth)acrylate. The content of the crosslinkable compound is preferably 0.1 to 30 parts by mass, and more preferably 0.1 to 20 parts by mass, per 100 parts by mass of the polymer component contained in the liquid crystal alignment agent.

The compound for adjusting the dielectric constant and electrical resistance is, for example, a monoamine having a nitrogen atom-containing aromatic heterocycle, such as 3-picolylamine. The content of the monoamine having a nitrogen atom-containing aromatic heterocycle is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, per 100 parts by mass of the polymer component contained in the liquid crystal alignment agent.

Preferred specific examples of the functional silane compounds 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, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, Examples of the functional silane include 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl methyl diethoxysilane, 3-glycidoxypropyl triethoxysilane, p-styryl trimethoxysilane, 3-methacryloxypropyl methyl dimethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-methacryloxypropyl methyl diethoxysilane, 3-methacryloxypropyl triethoxysilane, 3-acryloxypropyl trimethoxysilane, tris[3-(trimethoxysilyl)propyl]isocyanurate, 3-mercaptopropyl methyl dimethoxysilane, 3-mercaptopropyl trimethoxysilane, and 3-isocyanate propyl triethoxysilane. The content of the functional silane compound is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent.

As the compound for promoting the above-mentioned imidization, a compound having a basic site (e.g., a primary amino group, an aliphatic heterocycle (e.g., a pyrrolidine skeleton), an aromatic heterocycle (e.g., an imidazole ring, an indole ring), or a guanidino group, etc.) (excluding the above-mentioned crosslinking compound and adhesion aid), or a compound which generates the above-mentioned basic site upon baking, is preferred. A compound which generates the above-mentioned basic site upon baking is more preferred, and preferred specific examples include amino acids in which some or all of the basic sites of the amino acid are protected. Examples of protecting groups for the basic sites of the above-mentioned amino acids include carbamate-based protecting groups such as a Boc group. Specific examples of the above-mentioned amino acids include glycine, alanine, cysteine, methionine, asparagine, glutamine, valine, leucine, phenylalanine, tyrosine, tryptophan, proline, hydroxyproline, arginine, histidine, lysine, and ornithine. A more preferred example of the compound for promoting imidization is N-α-(9-fluorenylmethoxycarbonyl)-N-τ-(tert-butoxycarbonyl)-L-histidine. The content of the compound for promoting imidization contained in the liquid crystal alignment agent of the present invention is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, and even more preferably 5 to 20 parts by mass, relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent.

(Liquid crystal alignment film and liquid crystal display element)
The liquid crystal display element according to the present invention comprises a liquid crystal alignment film formed using the liquid crystal aligning agent.
The liquid crystal alignment film of the present invention can be produced, for example, by a method including the following steps (1) to (2) or a method including the following steps (1) to (3).
The operation mode of the liquid crystal display element is not particularly limited, and various operation modes can be applied, such as the TN mode, STN mode, vertical alignment mode (including the VA-MVA mode, VA-PVA mode, etc.), in-plane switching mode (IPS mode, FFS mode), and optical compensation bend mode (OCB mode).

The liquid crystal display element of the present invention can be produced, for example, by a method including the following steps (1) to (4), a method including steps (1) to (2) and (4), a method including steps (1) to (3), (4-2) and (4-4), or a method including steps (1) to (3), (4-3) and (4-4).
Moreover, one embodiment of the liquid crystal display element of the present invention is a liquid crystal display element having a liquid crystal alignment film formed by a method for producing a liquid crystal alignment film, the method including the following steps (1) to (2) or steps (1) to (3):

<Step (1): Step of applying liquid crystal alignment agent onto substrate>
Step (1) is a step of applying a liquid crystal alignment agent onto a substrate. A specific example of step (1) is as follows.
A liquid crystal alignment agent is applied to one side of a substrate on which a patterned transparent conductive film is provided, for example, by a suitable application method such as a roll coater method, a spin coat method, a printing method, or an inkjet method. The material of the substrate is not particularly limited as long as it is a highly transparent substrate, and plastics such as acrylic and polycarbonate can be used in addition to glass and silicon nitride. In addition, in a reflective liquid crystal display element, an opaque material such as a silicon wafer can be used for only one substrate, and in this case, a material that reflects light such as aluminum can be used for the electrode. In addition, when manufacturing an IPS or FFS liquid crystal display element, a substrate on which an electrode made of a transparent conductive film or a metal film patterned into a comb tooth shape is provided and an opposing substrate on which no electrode is provided are used.
An IPS substrate, which is a comb-tooth electrode substrate used in an IPS-type liquid crystal display element, has, for example, a base material, a plurality of linear electrodes formed on the base material and arranged in a comb-tooth shape, and a liquid crystal alignment film formed on the base material so as to cover the linear electrodes.
An FFS substrate, which is a comb-tooth electrode substrate used in an FFS-type liquid crystal display element, has, for example, a base material, a surface electrode formed on the base material, an insulating film formed on the surface electrode, a plurality of linear electrodes formed on the insulating film and arranged in a comb-tooth shape, and a liquid crystal alignment film formed on the insulating film so as to cover the linear electrodes.

Methods for applying the liquid crystal alignment agent to a substrate and forming a film include screen printing, offset printing, flexographic printing, the inkjet method, and the spray method. Among these, the inkjet method is the most suitable for application and film formation.

<Step (2): Step of baking the applied liquid crystal alignment agent>
In the step (2), the liquid crystal alignment agent applied on the substrate is baked to form a film. Specific examples of the step (2) are as follows.
After the liquid crystal alignment agent is applied to the substrate in step (1), the solvent can be evaporated or the polyimide precursor, typified by polyamic acid, can be thermally imidized by a heating means such as a hot plate, a hot air circulation oven, or an IR (infrared) oven. The drying and baking process after the application of the liquid crystal alignment agent can be performed at any temperature and time, and may be performed multiple times. The temperature for baking the liquid crystal alignment agent can be, for example, 40 to 180°C. From the viewpoint of shortening the process, it may be performed at 40 to 150°C. The baking time is not particularly limited, but may be 1 to 10 minutes or 1 to 5 minutes. When thermally imidizing a polyimide precursor, typified by polyamic acid, a baking process at, for example, 150 to 300°C or 150 to 250°C may be added after the above process. The baking time is not particularly limited, but may be 5 to 40 minutes or 5 to 30 minutes.
If the film-like material after firing is too thin, the reliability of the liquid crystal display device may decrease, so the film thickness is preferably 5 to 300 nm, and more preferably 10 to 200 nm.

<Step (3): Step of subjecting the film obtained in step (2) to an alignment treatment>
Step (3) is a step of subjecting the film obtained in step (2) to an alignment treatment, if necessary. That is, in a horizontal alignment type liquid crystal display element such as an IPS type or FFS type, an alignment ability imparting treatment is performed on the coating film. On the other hand, in a vertical alignment type liquid crystal display element such as a VA type or PSA type, 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 ability imparting treatment. Examples of the alignment treatment method for the liquid crystal alignment film include a rubbing alignment treatment method and a photo-alignment treatment method. Examples of the photo-alignment treatment method include a method in which the surface of the above-mentioned film-like material is irradiated with radiation, preferably polarized in a certain direction, and preferably heated to impart liquid crystal alignment (also called liquid crystal alignment ability). As the radiation, ultraviolet rays or visible light having a wavelength of 100 to 800 nm can be used. Among them, ultraviolet rays having a wavelength of 100 to 400 nm are preferable, and more preferably, ultraviolet rays having a wavelength of 200 to 400 nm are more preferable.

The radiation dose is preferably 1 to 10,000 mJ/cm ² , and more preferably 100 to 5,000 mJ/cm ^2. When irradiating with radiation, the substrate having the film-like material may be irradiated while being heated at 50 to 250° C. in order to improve the liquid crystal alignment. The liquid crystal alignment film thus produced can stably align liquid crystal molecules in a certain direction.
Examples of light sources for the irradiation light that can be used include low-pressure mercury lamps, high-pressure mercury lamps, deep UV lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, mercury-xenon lamps, excimer lasers (e.g., KrF excimer lasers), fluorescent lamps, LED lamps, halogen lamps (e.g., sodium lamps), and microwave-excited electrodeless lamps.
Furthermore, when polarized light is used as the irradiating light, the higher the extinction ratio of the polarized light, the higher the anisotropy that can be imparted. For example, in the case of ultraviolet light, the extinction ratio of the polarized ultraviolet light is more preferably 10:1 or greater, and even more preferably 20:1 or greater.

Furthermore, the coating film irradiated with polarized radiation or the coating film that has been subjected to rubbing alignment treatment by the above method may be subjected to a contact treatment using water or a solvent. Also, the film that has been subjected to the above alignment treatment may be subjected to a heat treatment without being subjected to a contact treatment. Furthermore, the film that has been subjected to the above contact treatment may be further subjected to a heat treatment.

The solvent used in the contact treatment is not particularly limited, so long as it dissolves the decomposition products generated from the film-like material 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, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, propyl acetate, butyl acetate, cyclohexyl acetate, and the like. The solvent may be one type or a combination of two or more types.

The temperature for the heat treatment of the coating film irradiated with the above radiation or the film that has been contact-treated is preferably 50 to 300°C, more preferably 120 to 300°C, even more preferably 150 to 300°C, and most preferably 150 to 250°C. The heat treatment time is preferably 1 to 30 minutes, respectively.

<Step (4): Step of Producing a Liquid Crystal Cell>
Two substrates on which the liquid crystal alignment film is formed as described above are prepared, and liquid crystal is disposed between the two substrates arranged opposite to each other. Specifically, the following two methods can be mentioned.
In the first method, first, two substrates are arranged facing each other with a gap (cell gap) between them so that the liquid crystal alignment films face each other, and then the peripheries of the two substrates are bonded together using a sealant, and a liquid crystal composition is injected into the substrate surfaces and the cell gap defined by the sealant so that the liquid crystal composition comes into contact with the film surface, and then the injection hole is sealed.

The second method is a method called ODF (One Drop Fill) method. For example, a UV-curable sealant is applied to a predetermined location on one of the two substrates on which a liquid crystal alignment film is formed, and a liquid crystal composition is dropped at several predetermined locations on the liquid crystal alignment film surface. Thereafter, the other substrate is bonded so that the liquid crystal alignment film faces the other substrate, and the liquid crystal composition is spread over the entire surface of the substrate and contacted with the film surface. Next, the entire surface of the substrate is irradiated with UV light to cure the sealant. In either method, it is preferable to remove the flow alignment during liquid crystal filling by heating to a temperature at which the liquid crystal composition used has an isotropic phase and then slowly cooling to room temperature.
When the coating film is subjected to a rubbing alignment treatment, the two substrates are disposed opposite to each other so that the rubbing directions of the coating films are at a predetermined angle, for example, perpendicular or anti-parallel to each other.
As the sealing agent, for example, an epoxy resin containing a hardener and aluminum oxide spheres as spacers can be used.
The liquid crystal composition is not particularly limited, and may be a composition containing at least one liquid crystal compound (liquid crystal molecule), and may be a liquid crystal composition exhibiting a nematic phase (hereinafter also referred to as nematic liquid crystal), a liquid crystal exhibiting a smectic phase, or a liquid crystal composition exhibiting a cholesteric phase, among which nematic liquid crystal is preferred. In addition, various liquid crystal compositions having positive or negative dielectric anisotropy may be used. In the following, a liquid crystal composition having a positive dielectric anisotropy is also referred to as a positive liquid crystal, and a liquid crystal composition having a negative dielectric anisotropy is also referred to as a negative liquid crystal.
The liquid crystal composition may contain a liquid crystal compound having a fluorine atom, a hydroxy group, an amino group, a fluorine atom-containing group (e.g., a trifluoromethyl group), a cyano group, an alkyl group, an alkoxy group, an alkenyl group, an isothiocyanate group, a heterocycle, a cycloalkane, a cycloalkene, a steroid skeleton, a benzene ring, or a naphthalene ring, and may contain a compound having two or more rigid moieties (mesogenic skeletons) that exhibit liquid crystallinity within the molecule (e.g., a bimesogenic compound in which two rigid biphenyl structures or terphenyl structures are linked by an alkyl group).
The liquid crystal composition may further contain an additive from the viewpoint of improving the liquid crystal alignment property. Such additives include a photopolymerizable monomer such as a compound having a polymerizable group (e.g., a (meth)acryloyl group), an optically active compound (e.g., S-811 manufactured by Merck Ltd.), an antioxidant, an ultraviolet absorber, a dye, an antifoaming agent, a polymerization initiator, or a polymerization inhibitor.
Examples of the positive type liquid crystal include ZLI-2293, ZLI-4792, MLC-2003, MLC-2041, MLC-3019, and MLC-7081 manufactured by Merck.
Examples of negative type liquid crystals include MLC-6608, MLC-6609, MLC-6610, MLC-7026, and MLC-7026-100 manufactured by Merck.
Furthermore, an example of a liquid crystal containing a compound having a polymerizable group is MLC-3023 manufactured by Merck.

The liquid crystal aligning agent of the present invention is also preferably used for a liquid crystal display element (PSA type liquid crystal display element) which has a liquid crystal layer between a pair of substrates provided with electrodes, and is manufactured through a process of disposing a liquid crystal composition containing a polymerizable compound which is polymerized by at least one of active energy rays and heat between the pair of substrates, and polymerizing the polymerizable compound by at least one of irradiation with active energy rays and heating while applying a voltage between the electrodes.
The liquid crystal aligning agent of the present invention is also preferably used for a liquid crystal display element (SC-PVA type liquid crystal display element) which has a liquid crystal layer between a pair of substrates having electrodes, and is manufactured through a process of disposing a liquid crystal alignment film containing a polymerizable group that is polymerized by at least one of active energy rays and heat between the pair of substrates, and applying a voltage between the electrodes.

<Step (4-2): In the case of a PSA type liquid crystal display element>
The method is carried out in the same manner as in (4) above, except that a liquid crystal composition containing a polymerizable compound is injected or dropped. Examples of the polymerizable compound include polymerizable compounds having one or more polymerizable unsaturated groups in the molecule, such as an acrylate group or a methacrylate group.

<Step (4-3): In the case of an SC-PVA type liquid crystal display element>
A method of manufacturing a liquid crystal display element through a step of irradiating ultraviolet light described later after the same procedure as in (4) above may be adopted. According to this method, a liquid crystal display element having excellent response speed can be obtained with a small amount of light irradiation, as in the case of manufacturing the PSA type liquid crystal display element. The compound having a polymerizable group may be a compound having one or more of the above-mentioned polymerizable unsaturated groups in the molecule, and the content thereof is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, relative to 100 parts by mass of the polymer component contained in the liquid crystal alignment agent. The polymerizable group may be contained in the polymer used in the liquid crystal alignment agent, and an example of such a polymer includes a polymer obtained by using a diamine component containing a diamine having the above-mentioned photopolymerizable group at its terminal in a reaction.

<Step (4-4): Step of irradiating with ultraviolet light>
The liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of the pair of substrates obtained in (4-2) or (4-3) above. The voltage applied here can be, for example, 5 to 50 V DC or AC. The light to be irradiated can be, for example, ultraviolet light and visible light containing light with a wavelength of 150 to 800 nm, but ultraviolet light containing light with a wavelength of 300 to 400 nm is preferred. The light source for the irradiation light can be, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, an excimer laser, or the like. The amount of light irradiation is preferably 1,000 to 200,000 J/m ² , more preferably 1,000 to 100,000 J/m ² .

Then, if necessary, a polarizing plate can be attached to the outer surface of the liquid crystal cell to obtain a liquid crystal display element. Examples of polarizing plates that can be attached to the outer surface of the liquid crystal cell include a polarizing film called an "H film" made by absorbing iodine while stretching and aligning polyvinyl alcohol, sandwiched between cellulose acetate protective films, and a polarizing plate made of the H film itself.

The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples. The abbreviations for compounds and solvents are as follows:

(Organic solvent)
NMP: N-methyl-2-pyrrolidone GBL: γ-butyrolactone BCS: Ethylene glycol monobutyl ether

(Diamine)
DA-1 to DA12: Compounds represented by the following structural formulas (DA-1) to (DA-12), respectively.

(Tetracarboxylic acid derivatives)
CA-1 to CA-5: Compounds represented by the following structural formulas (CA-1) to (CA-5), respectively.

(Compound (C))
Compound (c): dibutyl phosphite

(Additives)
AD-1: Compound represented by the following structural formula (AD-1) AD-2: 3-glycidoxypropyltriethoxysilane AD-3: 3-aminopropyltriethoxysilane AD-4: N-α-(9-fluorenylmethoxycarbonyl)-N-τ-(tert-butoxycarbonyl)-L-histidine

<Viscosity>
In the synthesis examples, the viscosity of the polymer solution was measured using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample amount of 1.1 mL, a cone rotor TE-1 (1°34′, R24), and a temperature of 25°C.

<Measurement of imidization rate of polyimide>
The imidization rate of the polyimide in the synthesis example was measured as follows. 30 mg of polyimide powder was placed in an NMR (nuclear magnetic resonance) sample tube (NMR sampling tube standard, φ5 (Kusano Scientific Co., Ltd.)), deuterated dimethyl sulfoxide (DMSO-d6, 0.05 mass % TMS (tetramethylsilane) mixture) (0.53 mL) was added, and the mixture was completely dissolved by applying ultrasonic waves. This solution was measured for proton NMR at 500 MHz using an NMR measurement device (JNW-ECA500) (JEOL Datum Co., Ltd.). The imidization rate was calculated by the following formula, using a proton derived from a structure that does not change before and after imidization as a reference proton, and the peak integrated value of this proton and the proton peak integrated value derived from the NH group of the amic acid that appears around 9.5 ppm to 10.0 ppm.
Imidization rate (%)=(1−α·x/y)×100

In the above formula, x is the integrated value of the proton peak derived from the NH group of the amic acid, y is the integrated value of the peak of the reference proton, and α is the ratio of the number of reference protons to one NH group proton of the amic acid in the case of polyamic acid (imidization rate 0%).

[Polymer synthesis]
(Synthesis Example 1)
In a 500 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, 2.16 g (20.0 mmol) of DA-5, 7.33 g (30.0 mmol) of DA-2, 9.61 g (30.0 mmol) of DA-6, and 7.97 g (20.0 mmol) of DA-10 were taken, and 311.3 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 20.85 g (93.0 mmol) of CA-2 was added, and 40.1 g of 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 obtain a polymer solution (polymer-1) (viscosity: 405 mPa s).

(Synthesis Example 2)
In a 100 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, 4.14 g (20.8 mmol) of DA-8 and 0.79 g (5.20 mmol) of DA-9 were placed, and 44.4 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 7.27 g (24.7 mmol) of CA-4 was added, and 45.1 g of NMP was further added so that the solid content concentration became 12 mass%, and the mixture was stirred for 24 hours while heating at 60°C under a nitrogen atmosphere to obtain a polymer solution (polymer-2) (viscosity: 398 mPa s).

(Synthesis Example 3)
7.45 g (26.0 mmol) of DA-1 was placed in a 100 ml four-neck flask equipped with a stirrer and a nitrogen inlet tube, 67.0 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. 4.86 g (24.8 mmol) of CA-3 was added to this diamine solution while stirring under water cooling, and 23.3 g of NMP was further added so that the solid content concentration became 12 mass%, and the mixture was stirred for 20 hours while heating at 50°C under a nitrogen atmosphere to obtain a polymer solution (polymer-3) (viscosity: 530 mPa s).

(Synthesis Example 4)
DA-3 0.99g (5.00mmol) and DA-8 3.99g (20.0mmol) were put into a 100ml four-neck flask equipped with a stirrer and a nitrogen inlet tube, and 57.2g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. This diamine solution was stirred under water cooling while adding 1.50g (5.00mmol) of CA-5 and 1.07g of NMP, and stirred for 3 hours under a nitrogen atmosphere and water cooling. Thereafter, 3.53g (18.0mmol) of CA-1 was added, and 31.8g of NMP was added so that the solid content concentration was 10% by mass, and the mixture was stirred again under a nitrogen atmosphere and water cooling for 3 hours to obtain a polymer solution (polymer-4) (viscosity: 165mPa·s).

(Synthesis Example 5)
In a 500 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, 3.24 g (30.0 mmol) of DA-5, 7.33 g (30.0 mmol) of DA-2, 3.00 g (20.0 mmol) of DA-11, and 6.83 g (20.0 mmol) of DA-7 were taken, and 234.7 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 20.85 g (93.0 mmol) of CA-2 was added, and 67.9 g of 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 obtain a polymer solution (polymer-5) (viscosity: 451 mPa s).

(Synthesis Example 6)
In a 500 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, 17.90 g (60.0 mmol) of DA-4 and 6.01 g (40.0 mmol) of DA-11 were placed, 275 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 18.43 g (94.0 mmol) of CA-1 was added, and 35.5 g of NMP was further added so that the solid content concentration became 12 mass%, and the mixture was stirred at room temperature for 24 hours to obtain a polymer solution (polymer-6) (viscosity: 503 mPa s).

(Synthesis Example 7)
In a 500 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, 2.60 g (24.0 mmol) of DA-1, 5.86 g (24.0 mmol) of DA-2, 4.13 g (16.0 mmol) of DA-12, and 5.46 g (16.0 mmol) of DA-7 were weighed out, 233.38 g of NMP was added, and the mixture was stirred and dissolved while feeding nitrogen. While stirring this diamine solution, 17.31 g (77.2 mmol) of CA-2 was added, and further, NMP was added so that the solid concentration became 12% by mass, and the mixture was stirred at 40 ° C. for 4 hours to obtain a polymer solution (polymer-7) (viscosity: 431 mPa s).

(Synthesis Example 8)
50 g of the polymer solution (Polymer-7) obtained in Synthesis Example 7 was weighed out into a 100 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and 25 g of NMP was added and stirred for 30 minutes. 4.16 g of acetic anhydride and 1.07 g of pyridine were added to the obtained polyamic acid solution, and the mixture was heated at 55° C. for 2 hours and 30 minutes to perform chemical imidization. The obtained reaction solution was poured into 300 mL of methanol while stirring, and the precipitate was filtered out. Subsequently, the precipitate was washed three times with 300 mL of methanol. Next, the obtained resin powder was dried at 60° C. for 12 hours to obtain a polyimide resin powder. The imidization rate of this polyimide resin powder was 70%.
4.80 g of the obtained polyimide resin powder was weighed out into a 100 mL Erlenmeyer flask containing a stirrer, 35.20 g of NMP was added, and the mixture was stirred at 70° C. for 12 hours to dissolve the polyimide resin powder, thereby obtaining a polymer solution (polymer-8) having a solid content of 12% by mass.

The specifications of the polymer obtained in the above synthesis example are shown in Table 1. In the table, the numbers in parentheses for the tetracarboxylic acid components indicate the amount (parts by mole) of each tetracarboxylic dianhydride used per 100 parts by mole of the total amount of tetracarboxylic acid components used in the polymerization. The numbers in parentheses for the diamine components indicate the amount (parts by mole) of each diamine used per 100 parts by mole of the total amount of diamine components used in the polymerization.

[Preparation of liquid crystal alignment agent]
Example 1
In a 30 mL Erlenmeyer flask containing a stirrer, the solution (9.17 g) of the polymer (polymer-1) obtained in Synthesis Example 1 was weighed out, and NMP (2.83 g), BCS (6.00 g), a 10 mass% NMP solution of AD-1 (0.56 g), a 1 mass% NMP solution of AD-2 (1.10 g), AD-4 (0.15 g), and compound (c) (0.20 g) were added, and the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (1).

Example 2
In a 30 mL Erlenmeyer flask containing a stirrer, the solution (3.67 g) of the polymer (polymer-1) obtained in Synthesis Example 1 and the solution (5.50 g) of the polymer (polymer-2) obtained in Synthesis Example 2 were weighed out, and NMP (2.83 g), BCS (6.00 g), 10 mass% NMP solution (0.56 g) of AD-1, 1 mass% NMP solution (1.10 g) of AD-2, AD-4 (0.15 g), and compound (c) (0.20 g) were added, and the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (2).

Example 3
In a 30 mL Erlenmeyer flask containing a stirrer, the solution (3.67 g) of the polymer (polymer-5) obtained in Synthesis Example 5 and the solution (5.50 g) of the polymer (polymer-6) obtained in Synthesis Example 6 were weighed out, and NMP (2.83 g), BCS (6.00 g), 10 mass% NMP solution of AD-1 (0.56 g), 1 mass% NMP solution of AD-2 (1.10 g), and compound (c) (0.20 g) were added, and the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (3).

Example 4
In a 30 mL Erlenmeyer flask containing a stirrer, the solution (3.00 g) of the polymer (polymer-8) obtained in Synthesis Example 8 and the solution (4.50 g) of the polymer (polymer-2) obtained in Synthesis Example 2 were weighed out, and NMP (0.86 g), GBL (6.00 g), BCS (4.00 g), 10 mass% NMP solution of AD-1 (0.45 g), 1 mass% NMP solution of AD-2 (0.90 g), AD-4 (0.09 g), and compound (c) (0.20 g) were added, and the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (4).

Example 5
In a 30 mL Erlenmeyer flask containing a stirrer, the solution (2.00 g) of the polymer (polymer-3) obtained in Synthesis Example 3 and the solution (9.60 g) of the polymer (polymer-4) obtained in Synthesis Example 4 were weighed out, and NMP (3.24 g), BCS (4.00 g), a 1 mass % NMP solution of AD-3 (0.96 g), and compound (c) (0.20 g) were added, and the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (5).

Example 6
The solution (9.17 g) of the polymer (polymer-6) obtained in Synthesis Example 6 was weighed out into a 30 mL Erlenmeyer flask containing a stirrer, and NMP (4.63 g), BCS (6.00 g), and compound (c) (0.20 g) were added thereto, followed by stirring at room temperature for 2 hours to obtain a liquid crystal alignment agent (6).

(Comparative Example 1)
In a 30 mL Erlenmeyer flask containing a stirrer, the solution (9.17 g) of the polymer (polymer-1) obtained in Synthesis Example 1 was weighed out, and NMP (3.03 g), BCS (6.00 g), a 10 mass% NMP solution of AD-1 (0.56 g), a 1 mass% NMP solution of AD-2 (1.10 g), and AD-4 (0.15 g) were added, and the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (7).

(Comparative Example 2)
In a 30 mL Erlenmeyer flask containing a stirrer, the solution (3.67 g) of the polymer (polymer-1) obtained in Synthesis Example 1 and the solution (5.50 g) of the polymer (polymer-2) obtained in Synthesis Example 2 were weighed out, and NMP (3.03 g), BCS (6.00 g), 10 mass% NMP solution of AD-1 (0.56 g), 1 mass% NMP solution of AD-2 (1.10 g), and AD-4 (0.15 g) were added, and the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (8).

(Comparative Example 3)
In a 30 mL Erlenmeyer flask containing a stirrer, the solution (3.67 g) of the polymer (polymer-5) obtained in Synthesis Example 5 and the solution (5.50 g) of the polymer (polymer-6) obtained in Synthesis Example 6 were weighed out, and NMP (3.03 g), BCS (6.00 g), a 10 mass% NMP solution (0.56 g) of AD-1, and a 1 mass% NMP solution (1.10 g) of AD-2 were added, and the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (9).

(Comparative Example 4)
In a 30 mL Erlenmeyer flask containing a stirrer, the solution (3.00 g) of the polymer (polymer-8) obtained in Synthesis Example 8 and the solution (4.50 g) of the polymer (polymer-2) obtained in Synthesis Example 2 were weighed out, and NMP (1.06 g), GBL (6.00 g), BCS (4.00 g), 10 mass% NMP solution of AD-1 (0.45 g), 1 mass% NMP solution of AD-2 (0.90 g), and AD-4 (0.09 g) were added, and the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (4).

(Comparative Example 5)
In a 30 mL Erlenmeyer flask containing a stirrer, the solution (2.00 g) of the polymer (polymer-3) obtained in Synthesis Example 3 and the solution (9.60 g) of the polymer (polymer-4) obtained in Synthesis Example 4 were weighed out, and NMP (3.44 g), BCS (4.00 g) and a 1 mass % NMP solution (0.96 g) of AD-3 were added, and the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal alignment agent (11).

(Comparative Example 6)
A solution (9.37 g) of the polymer (polymer-6) obtained in Synthesis Example 6 was weighed out into a 30 mL Erlenmeyer flask containing a stirrer, and NMP (4.63 g) and BCS (6.00 g) were added thereto, followed by stirring at room temperature for 2 hours to obtain a liquid crystal alignment agent (12).

The polymers of the liquid crystal aligning agents obtained in Examples 1 to 6 and Comparative Examples 1 to 6, and the types and ratios of the phosphite esters described in the present invention are as shown in Table 2 below.
In the table, the numerical values in parentheses for compound (C) indicate the content (parts by mass) of each compound relative to 100 parts by mass of the total amount of each liquid crystal aligning agent.

[Fabrication of FFS driving type liquid crystal cell (photo-alignment treatment)]
(Examples 7 to 10 and Comparative Examples 7 to 10)
A liquid crystal cell having the configuration of a liquid crystal display element of an FFS driving method was fabricated.
First, a substrate with electrodes was prepared. The substrate was a glass substrate with a size of 30 mm x 50 mm and a thickness of 0.7 mm. An ITO electrode with a solid pattern was formed on the substrate, which constituted the counter electrode as the first layer. A SiN (silicon nitride) film formed by a CVD method was formed as the second layer on the first layer of the counter electrode. The second layer of the SiN film was a 500 nm thick film that functioned as an interlayer insulating film. A comb-shaped pixel electrode formed by patterning an ITO film as the third layer was arranged on the second layer of the SiN film, and two pixels, a first pixel and a second pixel, were formed. The size of each pixel was 10 mm long and about 5 mm wide. At this time, the first layer of the counter electrode and the third layer of the pixel electrode were electrically insulated by the action of the second layer of the SiN film.

The pixel electrode of the third layer had a comb-tooth shape in which multiple electrode elements, each 3 μm wide and bent at an interior angle of 160° in the center, were arranged in parallel at intervals of 6 μm, and each pixel had a first region and a second region separated by a line connecting the bent portions of the multiple electrode elements.
When comparing the first and second regions of each pixel, the electrode elements of the pixel electrodes constituting them were formed in different directions. That is, when the direction connecting the bent portions of the above-mentioned multiple electrode elements was taken as a reference, the electrode elements of the pixel electrodes in the first region of the pixel were formed to form an angle of 80° clockwise, and the electrode elements of the pixel electrodes in the second region of the pixel were formed to form an angle of 80° counterclockwise. That is, in the first and second regions of each pixel, the directions of rotational movement (in-plane switching) of liquid crystal molecules in the substrate plane induced by application of a voltage between the pixel electrode and the counter electrode were configured to be opposite to each other.

Next, the liquid crystal alignment agents (1) to (4) and the liquid crystal alignment agents (7) to (10) obtained in Examples 1 to 4 and Comparative Examples 1 to 4 of the liquid crystal alignment agent were filtered through a 1.0 μm filter, and then applied by spin coating to the above-mentioned electrode-attached substrate and a glass substrate having a columnar spacer with a height of 4 μm and an ITO film formed on the back surface. After drying for 5 minutes on a hot plate at 80°C, it was baked for 30 minutes in a hot air circulation oven at 230°C to form a coating film with a thickness of 100 nm. Next, a photoalignment treatment was performed. Specifically, the coating surface was irradiated with linearly polarized ultraviolet light with a wavelength of 254 nm and an extinction ratio of 10:1 or more through a polarizing plate. The irradiation amount of the ultraviolet light was performed under the conditions shown in Table 3 below. Next, a heating process was performed in which the above-mentioned coating-attached substrate was heated on a hot plate at 230°C for 30 minutes, and a substrate with a liquid crystal alignment film was obtained.

Two of the above substrates with liquid crystal alignment film were prepared, and a sealant (Mitsui Chemicals XN-1500T) was printed around the periphery, leaving a liquid crystal injection port, and then they were bonded together so that the liquid crystal alignment film surfaces faced each other and the alignment direction was 0°. They were then heated at 120°C for 90 minutes to harden the sealant and create an empty cell. Negative liquid crystal MLC-7026-100 (Merck) was vacuum injected into this empty cell at room temperature, and the injection port was then sealed to create a liquid crystal cell with anti-parallel alignment. The resulting FFS drive type liquid crystal cell was heated at 120°C for 1 hour, left to stand overnight at 23°C, and then used for the various evaluations described below.

[Fabrication of FFS driving type liquid crystal cell (rubbing alignment treatment)]
(Examples 11 to 12 and Comparative Examples 11 to 12)
A substrate with electrodes similar to those described above and a glass substrate with columnar spacers were prepared. Then, a coating film with a thickness of 100 nm was formed in the same manner as in Examples 7 to 10, except that the liquid crystal alignment agents (5) to (6) and (11) to (12) obtained in Examples 5 to 6 and Comparative Examples 11 to 12 of the liquid crystal alignment agent were used. Next, the photo-alignment treatment was changed to the rubbing alignment treatment described below, and an alignment treatment was performed. Specifically, the substrate on which the coating film was formed was rubbed with a rayon cloth (roller diameter: 140 mm, roller rotation speed: 1000 rpm, moving speed: 30 mm/sec, indentation length: 0.3 mm). Thereafter, the substrate was cleaned by irradiating ultrasonic waves in pure water for 1 minute, water droplets were removed by air blowing, and then dried at 80°C for 10 minutes to obtain a substrate with a liquid crystal alignment film.
Two substrates with the liquid crystal alignment film thus obtained were prepared, and a liquid crystal cell of the FFS driving system was fabricated in the same manner as above, and used for the following evaluations.

[Evaluation of in-plane uniformity of contrast]
The variation in the twist angle of the liquid crystal cell was evaluated using AxoStep manufactured by AXOMETRICS. The liquid crystal cell prepared above was placed on a measurement stage, and the distribution of circular retardance in the pixel plane was measured without applying voltage, and 3σ, which is three times the standard deviation σ, was calculated. It can be said that the smaller the value of 3σ, the better the in-plane uniformity.

[Evaluation of image retention characteristics using long-term AC driving]
An AC voltage of ±5.8 V at a frequency of 60 Hz was applied to the FFS driving liquid crystal cell prepared above for 120 hours in a constant temperature environment of 60° C. Thereafter, the pixel electrode and the counter electrode of the liquid crystal cell were shorted, and the cell was left at room temperature for one day.
For the liquid crystal cell that had been subjected to the above-mentioned 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 in the absence of applied voltage was calculated as an angle Δθ.
Specifically, a liquid crystal cell was placed between two polarizing plates arranged so that the polarization axes were perpendicular to each other, and the backlight was turned on to adjust the arrangement angle of the liquid crystal cell so that the transmitted light intensity of the first region of the pixel was minimized. Next, the rotation angle (Δθ) required when the liquid crystal cell was rotated so that the transmitted light intensity of the second region of the pixel was minimized was calculated. It can be said that the smaller the value of this rotation angle, the better the afterimage characteristics due to long-term AC driving.

[Evaluation of voltage holding ratio]
The voltage holding ratio of the liquid crystal cell prepared above was evaluated. Specifically, an AC voltage of 2 VPP was applied to the liquid crystal cell obtained by the above method for 60 μs at a temperature of 60° C., the voltage after 1 second was measured, and the voltage that could be held was calculated as the voltage holding ratio (also referred to as VHR). The measurement was performed using a voltage holding ratio measuring device (VHR-1, manufactured by Toyo Corporation) with the settings of Voltage: ±1 V, Pulse Width: 60 μs, and Flame Period: 1000 ms.

The results of the evaluation of the above-mentioned in-plane contrast uniformity, afterimage characteristics during long-term AC operation, and voltage retention rate are shown in Table 5 below.

Comparing the results of Examples 7 to 12 and Comparative Examples 7 to 12, it was confirmed that the test cells using the liquid crystal alignment film to which the compound (c) was added had a better in-plane uniformity evaluation of contrast than the test cells using the liquid crystal alignment film to which the compound (c) was not added. In addition, comparing the results of Examples 7 to 10 and Comparative Examples 7 to 10, it was confirmed that when the liquid crystal alignment film to which the compound (c) was added was used, the afterimage characteristics due to long-term AC driving were also improved. Furthermore, comparing the results of Examples 8 and 11 with the results of Comparative Examples 8 and 11, it was confirmed that when the alignment film to which the compound (c) was added was used, the voltage holding ratio was improved.
In other words, it was confirmed that the liquid crystal display device using the liquid crystal aligning agent of the present invention has high contrast, excellent afterimage characteristics, and excellent reliability.

By using a liquid crystal display element having the configuration of the present invention, it is possible to obtain a liquid crystal display element in which the variation (non-uniformity) in the twist angle of the liquid crystal within the liquid crystal alignment film plane is small and AC afterimages can be suppressed. Furthermore, since a liquid crystal display element with a high voltage retention rate is obtained, it is expected that it will be used in liquid crystal display elements that require high display quality. These elements are also useful in liquid crystal displays for display purposes, and in light control windows and optical shutters that control the transmission and blocking of light.

Claims (17)

A liquid crystal aligning agent comprising a polymer component (P) containing one or more polymers, and a compound (C) represented by the following formula (c):
The liquid crystal aligning agent, wherein the polymer component (P) contains at least one polymer (P) selected from the group consisting of polyimide precursors and polyimides which are imidized products of the polyimide precursors.
(R _c O) _n P(=O)(OH) _2-n H (c)
(In formula (c), R _c 's each independently represent a monovalent organic group having 1 to 6 carbon atoms, and n is an integer of 1 or 2.) The liquid crystal aligning agent according to claim 1, wherein the monovalent organic group of R _c in the formula (c) is selected from 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, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or an aromatic group having 6 carbon atoms. The liquid crystal alignment agent according to claim 1, wherein the compound (C) is selected from methyl phosphite, ethyl phosphite, propyl phosphite, butyl phosphite, hexyl phosphite, phenyl phosphite, dimethyl phosphite, diethyl phosphite, dipropyl phosphite, dibutyl phosphite, dihexyl phosphite, or diphenyl phosphite. The polymer (P) has one or more structural units, and has at least one structural unit selected from the group consisting of a structural unit (p0) represented by the following formula (P0) and an imidized structural unit of the structural unit (p0). The liquid crystal aligning agent according to claim 1.

(In formula (P0), X represents a tetravalent organic group, and Y represents a divalent organic group. R and Z each independently represent a hydrogen atom or a monovalent organic group. A plurality of R and Z each independently have the above definition.) The liquid crystal aligning agent according to claim 4, wherein the divalent organic group of Y in the formula (P0) is a divalent organic group represented by the following formulas (3) to (4):

In formulas (3) and (4), R ₃ , R ₄ , and R _4′ each independently represent a halogen atom, a hydroxy group, an optionally protected amino group, a thiol group, a nitro group, a phosphate group, or a monovalent organic group having 1 to 20 carbon atoms.
_A4 represents an ester bond, an amide bond, a thioester bond, or a divalent organic group having 2 to 20 carbon atoms, except for a 1,4-phenylene group, a divalent organic group in which 1 to 4 hydrogen atoms on the phenylene group are substituted with _R4 and R4 _' , or a divalent organic group in which these divalent organic groups are linked to each other.
a3, a4, and a4' each independently represents an integer of 0 to 4.
a is an integer of 1 to 4. b and c are each independently an integer of 1 to 2. When a plurality of R ₃ , R ₄ , and R _4' are present, the structures of R ₃ , R ₄ , and R _4' may be the same or different. When a plurality of a3, a4, and a4' are present, they may be the same or different. * represents a bond. The liquid crystal aligning agent according to claim 1, wherein the polymer (P) is a polymer containing a structural unit having a divalent organic group selected from the group consisting of a divalent organic group having a urea bond, a divalent organic group having an amide bond, a nitrogen atom-containing heterocycle, a divalent organic group having at least one nitrogen atom-containing structure selected from the group consisting of a secondary amino group and a tertiary amino group, and a divalent organic group having a carboxy group. A liquid crystal aligning agent comprising a polymer component (P) containing two or more polymers, and a component (C),
The liquid crystal aligning agent, wherein the polymer component (P) satisfies at least one of the following conditions (i) to (iii):
(i) A polymer component (P1) having one or more types of structural units and including two or more types of at least one polymer selected from the group consisting of a polyimide precursor (A) having a structural unit (a1) represented by the following formula (A1) and a polyimide which is an imidized product of the polyimide precursor:
(ii) A polymer component (P2) which is a polymer different from the polyimide precursor (A), has one or more types of structural units, and contains two or more types of polyimide precursors (B) having a structural unit (b1) represented by the following formula (B1):
(iii) A polymer component (P3) containing at least one polymer selected from the group consisting of the polyimide precursor (A) and a polyimide which is an imidization product of the polyimide precursor (A), and the polyimide precursor (B).

(In formula (A1), X _a1 represents a tetravalent organic group selected from the group consisting of the following formulae (Xa1-1) to (Xa1-8), and Y _a1 represents a divalent organic group. Each of the multiple R's and Z's independently represents a hydrogen atom or a monovalent organic group.)

(In formulas (Xa1-1) to (Xa1-3), R ₁ to R ₁₅ each independently represent 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, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group, and may be the same or different. * represents a bond.)

(In formula (B1), X _b1 represents a tetravalent organic group having an aromatic group having 6 to 30 carbon atoms, and at least one of the carbonyl carbons bonded to X _b1 is bonded to the aromatic group of X _b1 . Y _b1 represents a divalent organic group. R and Z each independently represent a hydrogen atom or a monovalent organic group. A plurality of R's and Z's each independently have the above definition.) The liquid crystal alignment agent according to claim 1, wherein the polymer constituting the polymer component (P) does not have an acid-dissociable group. A liquid crystal alignment film obtained from the liquid crystal alignment agent according to any one of claims 1 to 8. A method for producing a liquid crystal alignment film, comprising the following steps (1) to (3):
Step (1): A step of applying the liquid crystal alignment agent according to claim 1 or 7 onto a substrate; Step (2): A step of baking the applied liquid crystal alignment agent; Step (3): A step of performing an alignment treatment on the film obtained in step (2). The method for producing a liquid crystal alignment film according to claim 10, wherein the alignment treatment is a photo-alignment treatment. The method for producing a liquid crystal alignment film according to claim 11, further comprising the following baking step after the step (3):
Firing step: A step of firing at 150°C to 300°C. A liquid crystal alignment film formed by the method for producing a liquid crystal alignment film according to claim 10. A liquid crystal display element comprising the liquid crystal alignment film according to claim 9. A liquid crystal display element comprising the liquid crystal alignment film according to claim 13. A method for manufacturing a liquid crystal display element, comprising forming the liquid crystal alignment film according to claim 9. A method for manufacturing a liquid crystal display element, comprising forming the liquid crystal alignment film according to claim 13.