WO2025079519A1 - Liquid crystal aligning agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Abstract

Provided are: a liquid crystal aligning agent which has excellent printability and from which it is possible to obtain a liquid crystal alignment film having a high voltage retention rate even when a negative type liquid crystal is used therein; a liquid crystal alignment film obtained from the liquid crystal aligning agent; and a liquid crystal display element using the liquid crystal alignment film.　This liquid crystal aligning agent contains a polymer (A) and a polymer other than said polymer (A). The contained amount of said polymer (A) is 0.1-10 parts by mass with respect to 100 parts by mass of the total contained amount of the polymer other than said polymer (A). Polymer (A): A polymer (P_A) selected from the group consisting of polyimide precursors obtained by using a tetracarboxylic acid derivative component including an alicyclic tetracarboxylic acid dianhydride and a diamine component including 40 mol% or more of a diamine (A) represented by formula (D_A) with respect to all diamine components, and polyimides which are imides of said polyimide precursors.　(D_A): Z-NH-Ar₁-X₁-(R₁-L)_n-R₂-X₂-Ar₂-NH-Z

Description

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

The present invention relates to a liquid crystal alignment agent, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display device having the liquid crystal alignment film.

Liquid crystal display elements are widely used in a wide range of applications, from small applications such as mobile phones and smartphones to relatively large applications such as televisions and monitors. In addition, various driving methods have been developed that differ in electrode structure and physical properties of the liquid crystal molecules used. For example, liquid crystal display elements using various modes such as the TN (Twisted Nematic) method, the STN (Super Twisted Nematic) method, the VA (Vertical Alignment) method, the IPS (In-Plane Switching) method, and the FFS (Fringe Field Switching) method are known. These liquid crystal display elements generally have a liquid crystal alignment film, which is essential for controlling the alignment state of the liquid crystal molecules. Polyamic acid and its derivatives (e.g., polyimide, etc.) are commonly used as materials for the liquid crystal alignment film.

Liquid crystal display elements are required to have high display quality, and Patent Document 1 discloses a composition for liquid crystal alignment films containing an aromatic diamine such as 1,5-bis(4-aminophenoxy)pentane. Patent Document 2 discloses a diamine in which two aromatic groups are linked to an alkylene ester chain via an ether bond, and a liquid crystal alignment agent containing a polyamic acid or a derivative thereof obtained by using the diamine as a raw material.
Furthermore, in liquid crystal display elements of the IPS mode, FFS mode, and the like, the use of negative liquid crystals has been investigated in order to improve contrast (Patent Document 3).

Japanese Patent Publication No. 06-194670 WO2022/220199 publication WO2016/152928 publication

A liquid crystal display element generally includes 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 liquid crystal molecules in the liquid crystal layer, and thin film transistors (TFTs) that switch electrical signals supplied to the pixel electrodes.
In recent years, large-screen, high-definition liquid crystal display elements have become mainstream, and standards for display elements with increased pixel counts, such as 4K and 8K, are being created. Liquid crystal alignment films are required to have the property of ensuring a uniform film thickness even over surface irregularities on substrates equipped with TFTs. Therefore, liquid crystal alignment agents with better printability than conventional liquid crystal alignment agents are required.
In addition, it has become clear that when negative type liquid crystals are applied to liquid crystal display elements, display defects such as image sticking (image sticking of sections and lines), unevenness, or smudges that occur over time due to external stimuli such as light and heat are likely to occur.
Therefore, in order to suppress the occurrence of these defects, a liquid crystal alignment film is required that has a high voltage holding ratio, which is a condition for providing so-called long-term reliability of display quality.

In view of the above, the object of the present invention is to provide a liquid crystal alignment agent that can obtain a liquid crystal alignment film with a high voltage retention rate even when a negative liquid crystal is used, and that has excellent printability, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element that uses the liquid crystal alignment film.

As a result of intensive research into achieving the above object, the inventors discovered that a liquid crystal alignment agent containing a specific polymer is effective in achieving the above objective, leading to the completion of the present invention.

The present invention relates to the following.
A liquid crystal aligning agent containing the following polymer (A) and a polymer other than the polymer (A),
The liquid crystal aligning agent, wherein the content of the polymer (A) is 0.1 parts by mass or more and 10 parts by mass or less, based on 100 parts by mass of the total content of the polymers other than the polymer (A).

Polymer (A): A polymer (P _{A ) selected from the group consisting of a polyimide precursor obtained using a tetracarboxylic acid derivative component containing an alicyclic tetracarboxylic acid dianhydride and a diamine component containing 40 mol % or more of a diamine (A) (hereinafter also referred to as specific diamine (A)) represented by the following formula (D A )} based on the total diamine component, and a polyimide which is an imidized product of the polyimide precursor.
Z-NH-Ar ₁ -X ₁ -(R ₁ -L) _n -R ₂ -X ₂ -Ar ₂ -NH-Z (D _A )
In formula (D _A ), Ar ₁ and Ar ₂ each independently represent a divalent aromatic group which is a divalent benzene ring, a biphenyl structure, or a naphthalene ring, and any hydrogen atom of the aromatic group may be replaced with a monovalent group.
X ₁ and X ₂ each independently represent a single bond, —O—, or *1-O—CO— (*1 represents a bond to Ar ₁ or Ar ₂ ).
R ₁ and R ₂ are each independently a divalent hydrocarbon group, and some of the hydrogen atoms in the divalent hydrocarbon group may be substituted with halogen atoms, methyl groups, trifluoromethyl groups, or hydroxy groups. Multiple R _1s may be the same or different.
L represents -O-, -C(=O)-, -O-C(=O)- or -C(=O)-O-. When a plurality of Ls are present, the plurality of Ls may be the same or different, provided that at least one L represents -O-C(=O)- or -C(=O)-O-.
n is an integer from 1 to 6.
Z represents a hydrogen atom or a monovalent organic group. Multiple Z's may be the same or different.
In the present invention, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

The present invention provides a liquid crystal alignment film that has a high voltage retention rate even when a negative liquid crystal is used, and also provides a liquid crystal alignment agent with excellent printability, a liquid crystal alignment film obtained from the liquid crystal alignment agent, a liquid crystal display element using the liquid crystal alignment film, and compounds and polymers that can be used therein.

The mechanism by which the above-mentioned effects of the present invention are obtained is not entirely clear, but is roughly presumed to be as follows. First, the polymer (A) contained in the liquid crystal alignment agent of the present invention contains a structure formed by a tetracarboxylic acid derivative component containing an alicyclic tetracarboxylic dianhydride and the above-mentioned specific diamine (A). In addition, since the polymer (A) contains an ester bond derived from the above-mentioned specific diamine (A) in its repeating unit structure, it is believed that the voltage retention rate is improved by the trap phenomenon that interacts with ionic impurities that cause display defects and suppresses the diffusion of impurities. In addition, since the polymer (A) contains a small amount of the polymer (A) with a highly flexible molecular structure and contains polymers other than the polymer (A) and the polymer (A), it is believed that the aggregation between the polymers is suppressed, resulting in the development of excellent printability.

1 is a schematic partial cross-sectional view showing an example of a horizontal electric field liquid crystal display element of the present invention. FIG. 4 is a schematic partial cross-sectional view showing another example of a horizontal electric field liquid crystal display element of the present invention.

The liquid crystal aligning agent of the present invention is a liquid crystal aligning agent containing the above polymer (A) and a polymer other than the polymer (A),
The content of polymer (A) is 0.1 parts by mass or more and 10 parts by mass or less, based on 100 parts by mass of the total content of polymers other than polymer (A). However, the polymers other than polymer (A) do not include those included in the definition of polymer (A).

<Polymer (A)>
The polymer (A) contained in the liquid crystal aligning agent of the present invention is a polymer (P _A ) selected from the group consisting of a polyimide precursor obtained by using a tetracarboxylic acid derivative component containing an alicyclic tetracarboxylic acid dianhydride and a diamine component containing 40 mol % or more of a diamine (A) (hereinafter also referred to as specific diamine (A)) represented by the following formula (D _A ) based on the total diamine component, and a polyimide which is an imidized product of the polyimide precursor. The polymer (A) may be one type or two or more types of polymers (P _A ).
Z-NH-Ar ₁ -X ₁ -(R ₁ -L) _n -R ₂ -X ₂ -Ar ₂ -NH-Z (D _A )
In formula (D _A ), Ar ₁ and Ar ₂ each independently represent a divalent aromatic group which is a divalent benzene ring, a biphenyl structure, or a naphthalene ring, and any hydrogen atom of the aromatic group may be replaced with a monovalent group.
X ₁ and X ₂ each independently represent a single bond, —O—, or *1-O—CO— (*1 represents a bond to Ar ₁ or Ar ₂ ).
R ₁ and R ₂ are each independently a divalent hydrocarbon group, and some of the hydrogen atoms in the divalent hydrocarbon group may be substituted with halogen atoms, methyl groups, trifluoromethyl groups, or hydroxy groups. Multiple R _1s may be the same or different.
L represents -O-, -C(=O)-, -O-C(=O)- or -C(=O)-O-. When a plurality of Ls are present, the plurality of Ls may be the same or different, provided that at least one L represents -O-C(=O)- or -C(=O)-O-.
n is an integer from 1 to 6.
Z represents a hydrogen atom or a monovalent organic group. Multiple Z's may be the same or different.

In the above formula (D _A ), R ₁ and R ₂ are each independently a divalent hydrocarbon group, examples of which include, but are not limited to, a linear or branched alkylene group, -CH═CH-, a phenylene group, or a cyclohexylene group.
From the viewpoint of obtaining high liquid crystal alignment properties, R ₁ and R ₂ are preferably a hydrocarbon group having 2 to 6 carbon atoms, more preferably an alkylene group having 2 to 4 carbon atoms, and further preferably an alkylene group having 2 or 4 carbon atoms.
A part of the hydrogen atoms of the divalent hydrocarbon group may be substituted with a halogen atom, a methyl group, a trifluoromethyl group, or a hydroxy _group , and the halogen atom substituting the hydrogen atom of the divalent hydrocarbon group is preferably a fluorine atom.
L represents -O-, -C(=O)-, -O-C(=O)-, or -C(=O)-O-. When a plurality of Ls are present, the plurality of Ls may be the same as or different from each other. However, it is preferable that at least one L represents -O-C(=O)- or -C(=O)-O-, and at least two Ls represent -O-C(=O)- or -C(=O)-O-. n represents an integer of 1 to 6, preferably an integer of 1 to 4, more preferably an integer of 2 to 4, and even more preferably an integer of 2 or 4.

More preferred specific examples of the group "*-(R ₁ -L) _n -R ₂ -*" in the above formula (D _A ) include the following structures.
*-(CH ₂ ) _p -O-C(=O)-(CH ₂ ) _q -C(=O)-O-(CH ₂ ) _r -*,
*-(CH ₂ ) _p -C(=O)-O-(CH ₂ ) _q -O-C(=O)-(CH ₂ ) _r -*,
*-(CH ₂ ) _n1 -O-C(=O)-(CH ₂ ) _n2 -C(=O)-O-(CH ₂ ) _n3 -O-C(=O)-(CH ₂ ) _n4 -C(=O)-O-(CH ₂ ) _n5 -*;
*-(CH ₂ ) _n1 -C(=O)-O-(CH ₂ ) _n2 -O-C(=O)-(CH ₂ ) _n3 -C(=O)-O-(CH ₂ ) _n4 -O-C(=O)-(CH ₂ ) _n5 -*;
In the above, p, q, and r each independently represent an integer of 1 to 6.
n1 to n5 each independently represents an integer of 1 to 6, provided that the total number of carbon atoms in n1 to n5 is 20 or less.
* represents a bond.

Examples of the monovalent group substituting the hydrogen atom of the divalent aromatic group of Ar ₁ and Ar ₂ in the above formula (D _A ) include a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkenyl group having 2 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, a carboxy group, a hydroxy group, an alkyloxycarbonyl group having 1 to 10 carbon atoms, a cyano group, a nitro group, etc. Among these, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluoroalkyl group having 1 to 5 carbon atoms, or a fluoroalkoxy group having 1 to 5 carbon atoms is preferred.
The bonding positions of the benzene ring in _Ar1 and _Ar2 , in which any hydrogen atom on the ring may be substituted, are preferably the 1-position and the 4-position, the bonding positions of the biphenyl structure, in which any hydrogen atom on the ring may be substituted, are preferably the 4- and 4'-position, and the bonding positions of the naphthalene ring, in which any hydrogen atom on the ring may be substituted, are preferably the 2- and 6-position.

Preferred examples of the divalent aromatic group represented by Ar ₁ and Ar ₂ include 1,4-phenylene, 1,3-phenylene, 2-methyl-1,4-phenylene, 2-ethyl-1,4-phenylene, 2-propyl-1,4-phenylene, 2-butyl-1,4-phenylene, 2-isopropyl-1,4-phenylene, 2-tert-butyl-1,4-phenylene, 2-methoxy-1,4-phenylene, 2-ethoxy-1,4-phenylene, 2-propoxy-1,4-phenylene, 2-butoxy-1,4-phenylene, and the like. phenylene, 2-fluoro-1,4-phenylene, 2,3-dimethyl-1,4-phenylene, 2,6-dimethyl-1,4-phenylene, 4-methyl-1,3-phenylene, 5-methyl-1,3-phenylene, 4-fluoro-1,3-phenylene, 2,3,5,6-tetramethyl-1,4-phenylene, 4,4'-biphenylylene, 2-methyl-4,4'-biphenylylene, 2-ethyl-4,4'-biphenylylene, 2-propyl-4,4'-biphenylylene, 2-butyl-4 ,4'-biphenylylene, 2-tert-butyl-4,4'-biphenylylene, 2-methoxy-4,4'-biphenylylene, 2-ethoxy-4,4'-biphenylylene, 2-fluoro-4,4'-biphenylylene, 3-methyl-4,4'-biphenylylene, 3-ethyl-4,4'-biphenylylene, 3-propyl-4,4'-biphenylylene, 3-butyl-4,4'-biphenylylene, 3-tert-butyl-4,4'-biphenylylene, 3-methoxy-4,4'-biphenylylene biphenylylene, 3-ethoxy-4,4'-biphenylylene, 3-fluoro-4,4'-biphenylylene, 2,2'-dimethyl-4,4'-biphenylylene, 3,3'-dimethyl-4,4'-biphenylylene, 3,3'-biphenylylene, 5-methyl-3,3'-biphenylylene, 5,5'-dimethyl-3,3'-biphenylylene, 1,4-naphthylene, 1,5-naphthylene, 1,6-naphthylene, 1,7-naphthylene, 2,6-naphthylene, 2,7-naphthylene, and the like.

Examples of the monovalent organic group for Z in formula (D _A ) above include monovalent hydrocarbon groups having 1 to 6 carbon atoms, monovalent group A obtained by replacing a methylene group of the hydrocarbon group with -O-, -S-, -CO-, -COO-, -COS-, -NR ³ -, -CO-NR ³ -, -Si(R ³ ) ₂ - (wherein R ³ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms), -SO ₂ - or the like, monovalent groups obtained by replacing at least one hydrogen atom bonded to a carbon atom of the monovalent hydrocarbon group or the monovalent group A 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, and monovalent groups having a heterocycle.
As the monovalent organic group for Z in the above formula (D _A ), among others, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, or a tert-butoxycarbonyl group 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, Z is preferably each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group.

Preferred examples of the above formula (D _A ) include the following formulae (d _A -1) to (d _A -10).
In addition, the hydrogen atoms on the benzene rings in the following formulas (d _A -1) to (d _A -10) may be substituted with monovalent substituents, and preferred specific examples of the substituents include the structures exemplified as the monovalent groups substituting the hydrogen atoms of the divalent aromatic groups of Ar ₁ and Ar ₂ in the above formula (D _A ).
p, q, r, and n1 to n5 are the same as defined above.

The polymer (P _A ) is, for example, a polyimide precursor obtained by using a tetracarboxylic acid derivative component containing an alicyclic tetracarboxylic acid dianhydride and a diamine component containing the specific diamine (A), or a polyimide which is an imidized product of the polyimide precursor. Here, examples of the polyimide precursor include, but are not limited to, polymers that can be imidized to obtain polyimide, such as polyamic acid and polyamic acid ester.

The polyamic acid (P _A '), which is a polyimide precursor of the polymer (P _A ), can be obtained by a polymerization reaction between a diamine component containing the specific diamine (A) and a tetracarboxylic acid component. The specific diamine (A) may be used alone or in combination of two or more.
The amount of the specific diamine (A) used is preferably 45 mol % or more, more preferably 50 mol % or more, and even more preferably 60 mol % or more, based on the total diamine components.

The diamine component used in the production of the polyamic acid (P _A ') may contain a diamine other than the specific diamine (A) (hereinafter also referred to as other diamine 1). When other diamine 1 is used in addition to the specific diamine (A), the amount of the specific diamine (A) used relative to the diamine component is preferably 90 mol % or less, more preferably 80 mol % or less.

（Ｂｏｃは、ｔｅｒｔ－ブトキシカルボニル基を表す。＊は結合手を表す。）

　上記式（Ｖ－１）中、ｍ、ｎは１～３の整数であり、１≦ｍ＋ｎ≦４を満たす。ｊは０又は１の整数である。Ｘ^１は、－（ＣＨ_２）_ａ－（ａは１～１５の整数である。）、－ＣＯＮＨ－、－ＮＨＣＯ－、－ＣＯ－Ｎ（ＣＨ_３）－、－ＮＨ－、－Ｏ－、－ＣＨ_２Ｏ－、－ＣＨ_２－ＯＣＯ－、－ＣＯＯ－、又は－ＯＣＯ－を表す。Ｒ^１は、フッ素原子、炭素数１～１０のフッ素原子含有アルキル基、炭素数１～１０のフッ素原子含有アルコキシ基、炭素数１～１０のアルキル基、炭素数１～１０のアルコキシ基、及び炭素数２～１０のアルコキシアルキル基などの１価の基を表す。上記式（Ｖ－２）中、Ｘ^２は－Ｏ－、－ＣＨ_２Ｏ－、－ＣＨ_２－ＯＣＯ－、－ＣＯＯ－、又は－ＯＣＯ－を表す。ｍ、ｎ、Ｘ^１、Ｒ^１が２つ存在する場合、それぞれ独立して上記定義を有する。 Examples of the other diamine 1 are given below, but are not limited thereto. The other diamines may be used alone or in combination of two or more thereof. p-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, m-phenylenediamine, 2,4-dimethyl-m-phenylenediamine, 2,5-diaminotoluene, 2,6-diaminotoluene, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4'-diaminobiphenyl, 2,2'-difluoro-4,4'-diaminobiphenyl, 3,3'-difluoro-4,4'-diaminobiphenyl, phenyl, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,3'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 4,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 2,2'-diaminobiphenyl, 2,3'-diaminobiphenyl, specific diamine (B) described below, 1,4-phenylenebis(4-aminobenzoate), 1,4-phenylenebis(3-aminobenzoate), 1,3-phenylenebis(4-aminobenzoate), 1,3-phenylenebis(3-aminobenzoate), bis(4-aminophenyl) phenyl) terephthalate, bis(3-aminophenyl) terephthalate, bis(4-aminophenyl) isophthalate, bis(3-aminophenyl) isophthalate; diamines having a photoalignment group such as 4,4'-diaminoazobenzene or diaminotolane; diamines having a photopolymerizable group at the end such as 2-(2,4-diaminophenoxy)ethyl methacrylate or 2,4-diamino-N,N-diallylaniline; 1-(4-(2-(2,4-diaminophenoxy)ethoxy)phenyl)-2-hydroxy-2-methylpropanone, 2-(4-(2-hydroxy-2-methylpropanoyl)phenoxy)ethoxy diamines having a radical polymerization initiator function such as 4,4'-diaminobenzanilide; diamines having an amide bond such as 4,4'-diaminobenzanilide; diamines having a urea bond such as 1,3-bis(4-aminophenyl)urea, 1,3-bis(4-aminobenzyl)urea, and 1,3-bis(4-aminophenethyl)urea; 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenethyl)urea, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)diphenyl ether, 1,4-bis[4-(4-aminophenoxy)phenoxy]benzene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis(3-aminophenyl)hexafluoropropane, 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane, 2,2-bis(4-aminophenyl)propane, 2,2-bis(3-aminophenyl) 2,6-diaminopyridine, specific diamine (C) described below, 2,4-diaminophenol, 3,5-diaminophenol, 3,5-diaminobenzyl alcohol, 2,4-diaminobenzyl alcohol, 4,6-diaminoresorcinol, 4,4'-diamino-3,3'-dihydroxybiphenyl; 2,4-diaminobenzoic acid, 2,5- Diaminobenzoic acid, 3,5-diaminobenzoic acid, 4,4'-diaminobiphenyl-3-carboxylic acid, 4,4'-diaminodiphenylmethane-3-carboxylic acid, 4,4'-diaminodiphenylethane-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, 4,4'-diaminodiphenylethane-3,3'-dicarboxylic acid, 4,4'- Diamines having a carboxy group, such as diaminodiphenylether-3,3'-dicarboxylic acid; 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; groups such as "-N(D)-" in the following formulae (5-1) to (5-8) (D represents a protecting group which is eliminated by heating and replaced with a hydrogen atom, preferably a carbamate-based protecting group, more preferably a tert-butoxycarbonyl group). diamines having a steroid skeleton such as 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 represented by the following formulae (V-1) to (V-2); diamines having a siloxane bond, such as meta-xylylenediamine, 1,3-propanediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-diaminocyclohexane, 4,4'-methylenebis(cyclohexylamine), and diamines in which two amino groups are bonded to a group represented by any one of formulas (Y-1) to (Y-167) described in WO2018/117239.

(Boc represents a tert-butoxycarbonyl group. * represents a bond.)

In the above formula (V-1), m and n are integers of 1 to 3, and satisfy 1≦m+n≦4. j is an integer of 0 or 1. ^{X 1} represents -(CH ₂ ) _a - (a is an integer of 1 to 15), -CONH-, -NHCO-, -CO-N(CH ₃ )-, -NH-, -O-, -CH ₂ O-, -CH ₂ -OCO-, -COO-, or -OCO-. R ¹ represents a monovalent group such as a fluorine atom, a fluorine atom-containing alkyl group having 1 to 10 carbon atoms, a fluorine atom-containing alkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, and an alkoxyalkyl group having 2 to 10 carbon atoms. In the above formula (V-2), X ² represents —O—, —CH ₂ O—, —CH ₂ —OCO—, —COO—, or —OCO—, and when there are two of m, n, X ¹ and R ¹ , each independently has the above definition.

When the other diamine 1 is used in addition to the specific diamine (A), the amount of the other diamine 1 used is preferably 10 to 60 mol %, more preferably 20 to 55 mol %, based on the total diamine components used in the production of the polymer (P _A ).

(Tetracarboxylic Acid Component of Polymer (P _A ))
When producing the polyamic acid (P _A '), the tetracarboxylic acid component to be reacted with the diamine component may be not only an alicyclic tetracarboxylic acid dianhydride, but also a derivative of an alicyclic tetracarboxylic acid dianhydride, such as an alicyclic tetracarboxylic acid, an alicyclic tetracarboxylic acid dihalide, an alicyclic tetracarboxylic acid dialkyl ester, or an alicyclic tetracarboxylic acid dialkyl ester dihalide.

Here, the alicyclic tetracarboxylic acid dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxy groups, including at least one carboxy group bonded to an alicyclic structure. However, none of these four carboxy groups is bonded to an aromatic ring. In addition, it is not necessary for the alicyclic structure to be composed only of the alicyclic structure, and it may have a chain hydrocarbon structure or an aromatic ring structure as a part of it.
The alicyclic tetracarboxylic dianhydride or derivative thereof more preferably contains a tetracarboxylic dianhydride or derivative thereof having at least one partial structure selected from the group consisting of a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring, and particularly preferably contains a tetracarboxylic dianhydride or derivative thereof having at least one structure selected from the group consisting of a cyclobutane ring, a cyclopentane ring, and a cyclohexane ring.
The tetracarboxylic acid component that can be used in the production of the polyamic acid (P _A ') preferably contains the following alicyclic tetracarboxylic acid dianhydride or a derivative thereof (in the present invention, these are also collectively referred to as specific alicyclic tetracarboxylic acid derivative (A)):
1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,3-dichloro-1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,3-difluoro-1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,3-bis(trifluoromethyl)-1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclopentane tetracarboxylic dianhydride, 1,2,4,5-cyclohexane tetracarboxylic dianhydride, 3,3',4,4'-dicyclohexyl tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic dianhydride Water, 4-(2,5-dioxotetrahydrofuran-3-yl)tetrahydronaphthalene-1,2-dicarboxylic acid dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione ,3-dione, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, bicyclo[2.2.2]octane-2,3,5,6-tetracarboxylic dianhydride, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride and other alicyclic tetracarboxylic dianhydrides; and tetracarboxylic dianhydrides as described in JP-A-2010-97188.

More preferred examples of the specific alicyclic tetracarboxylic acid derivative (A) include 1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,2-dimethyl-1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,3-difluoro-1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,3-bis(trifluoromethyl)-1,2,3,4-cyclobutane tetracarboxylic acid dianhydride, 1,2,3,4-cyclopentane tetracarboxylic acid dianhydride, anhydride, 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 3,3',4,4'-dicyclohexyltetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, or derivatives thereof.

The proportion of the specific alicyclic tetracarboxylic acid derivative (A) used is preferably 10 mol % or more, more preferably 20 mol % or more, and even more preferably 50 mol % or more, based on the total tetracarboxylic acid components used.

The tetracarboxylic acid component used in the production of the polyamic acid (P _A ') may contain a tetracarboxylic acid derivative other than the alicyclic tetracarboxylic acid derivative (A) (hereinafter, also referred to as other tetracarboxylic acid derivative). When the other tetracarboxylic acid derivative is used in combination with the alicyclic tetracarboxylic acid derivative (A), the amount of the alicyclic tetracarboxylic acid derivative (A) used relative to the tetracarboxylic acid component is preferably 90 mol % or less, more preferably 80 mol % or less.

Examples of the other tetracarboxylic acid derivatives include acyclic aliphatic tetracarboxylic acid dianhydrides, aromatic tetracarboxylic acid dianhydrides, and derivatives thereof.
Acyclic aliphatic tetracarboxylic acid dianhydrides are acid dianhydrides obtained by intramolecular dehydration of four carboxy groups bonded to a chain hydrocarbon structure, but do not necessarily have to be composed of a chain hydrocarbon structure alone, and may have an alicyclic structure or an aromatic ring structure as part of the structure.
The 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.
Among them, the aromatic tetracarboxylic acid derivative more preferably contains a tetracarboxylic acid dianhydride having a benzene ring or a derivative thereof.

As other tetracarboxylic acid derivatives that can be used in the production of the above polyamic acid (P _A '), preferably, the following tetracarboxylic dianhydrides or derivatives thereof can be mentioned.
Acyclic aliphatic tetracarboxylic dianhydrides such as 1,2,3,4-butane tetracarboxylic dianhydride; pyromellitic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-biphenylsulfone tetracarboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 3,3',4,4'-biphenyl ether tetracarboxylic dianhydride, 3,3',4,4'-perfluoroisopropylidenediphthalic dianhydride, 3,3',4,4'-biphenyl tetracarboxylic dianhydride , aromatic tetracarboxylic dianhydrides such as 2,2',3,3'-biphenyltetracarboxylic dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylpropane dianhydride, ethylene glycol bisanhydrotrimate, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 4,4'-carbonyldiphthalic anhydride, 4,4'-oxydi(1,4-phenylene)bis(phthalic) dianhydride, or 4,4'-methylenedi(1,4-phenylene)bis(phthalic) dianhydride; and tetracarboxylic dianhydrides as described in JP-A-2010-97188.

More preferred examples of the above other tetracarboxylic acid derivatives include 1,2,3,4-butanetetracarboxylic dianhydride, pyromellitic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 3,3',4,4'-biphenylsulfonetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3',4,4'-biphenylethertetracarboxylic dianhydride, 3,3',4, 4'-perfluoroisopropylidenediphthalic dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 4,4'-bis(3,4-dicarboxyphenoxy)diphenylpropane dianhydride, 4,4'-carbonyldiphthalic anhydride, 4,4'-oxydi(1,4-phenylene)bis(phthalic) dianhydride, 4,4'-methylenedi(1,4-phenylene)bis(phthalic) dianhydride, or derivatives thereof.

<Polymers other than polymer (A)>
The polymer other than the polymer (A) contained in the liquid crystal aligning agent of the present invention is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane and addition polymer. From the viewpoint of suitably obtaining the effects of the present invention, it is preferable to contain the following polymer (B) and/or the following polymer (C) as the polymer other than the above polymer (A), and it is more preferable to contain the polymer (B) and the polymer (C).

（Ａｒ_１、及びＡｒ_１’は、それぞれ、ベンゼン環、ビフェニル構造、又はナフタレン環を表し、該ベンゼン環、該ビフェニル構造、又は該ナフタレン環上の１つ以上の水素原子は１価の基で置換されてもよい。
　Ｌ_１及びＬ_１’は、それぞれ、単結合、－Ｏ－、－Ｃ（＝Ｏ）－、又は－Ｏ－Ｃ（＝Ｏ）－を表す。Ａは、－ＣＨ_２－、炭素数２～１２のアルキレン基、又は該アルキレン基の炭素－炭素結合の間に、－Ｏ－、－Ｃ（＝Ｏ）－Ｏ－、及び－Ｏ－Ｃ（＝Ｏ）－の少なくともいずれかの基が挿入されてなる２価の有機基を表す。Ａが有する任意の水素原子は、ハロゲン原子で置換されていてもよい。
　ただし、式（ｄ_ＡL）中のＬ_１及びＬ_１’が－Ｏ－の場合、Ａは、－ＣＨ_２－、炭素数２～１２のアルキレン基、又は該アルキレン基の炭素－炭素結合の間に－Ｏ－が挿入されてなる２価の有機基を表す。
　上記ベンゼン環、ビフェニル構造、又はナフタレン環上の１つ以上の水素原子は１価の基で置換されてもよく、該１価の基としては、ハロゲン原子、炭素数１～３のアルキル基、炭素数２～３のアルケニル基、炭素数１～３のアルコキシ基、炭素数１～３のフルオロアルキル基、炭素数２～３のフルオロアルケニル基、炭素数１～３のフルオロアルコキシ基、炭素数２～３のアルキルオキシカルボニル基、シアノ基、ニトロ基等が挙げられる。
　Ａｒ_１、及びＡｒ_１’における環上の任意の水素原子が置換されてもよいベンゼン環の結合位置は１位及び４位が好ましく、環上の任意の水素原子が置換されてもよいビフェニル構造の結合位置は４，４’位が好ましい。また、Ａｒ_１、及びＡｒ_１’における環上の任意の水素原子が置換されてもよいナフタレン環の結合位置は２，６位が好ましい。
　Ｚは水素原子又は１価の有機基を表す。複数のＺは、互いに同一であってもよく、異なっていても良い。） <Polymer (B)>
The polymer (B) is a polymer (P B ) selected from the group consisting of polyimide precursors obtained by using a diamine component containing a diamine (B) represented by the following formula (d _AL ) (hereinafter also referred to as specific diamine ( _B ), except for those included in specific diamine (A)) and polyimides which are imidized products of the polyimide precursors. The polymer (B) may be one type or two or more types of polymers (P _B ).
However, when the diamine component contains a diamine other than the specific diamine (B) and contains the specific diamine (A), the amount of the specific diamine (A) used is less than 40 mol % based on the total diamine components. When the diamine component contains a diamine other than the specific diamine (B), does not contain the specific diamine (A), and contains the following specific diamine (C), the amount of the specific diamine (C) used is less than 30 mol % based on the total diamine components.

(Ar ₁ and Ar _1′ each represent a benzene ring, a biphenyl structure, or a naphthalene ring, and one or more hydrogen atoms on the benzene ring, the biphenyl structure, or the naphthalene ring may be substituted with a monovalent group.
_L1 and L1 _' each represent a single bond, -O-, -C(=O)-, or -O-C(=O)-. A represents _-CH2- , an alkylene group having 2 to 12 carbon atoms, or a divalent organic group in which at least one of -O-, -C(=O)-O-, and -O-C(=O)- is inserted between the carbon-carbon bonds of the alkylene group. Any hydrogen atom possessed by A may be substituted with a halogen atom.
However, when L ₁ and L _1' in formula (d _AL ) are -O-, A represents -CH ₂ -, an alkylene group having 2 to 12 carbon atoms, or a divalent organic group in which -O- is inserted between the carbon-carbon bonds of the alkylene group.
One or more hydrogen atoms on the benzene ring, biphenyl structure, or naphthalene ring may be substituted with a monovalent group. Examples of the monovalent group include a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, a fluoroalkenyl group having 2 to 3 carbon atoms, a fluoroalkoxy group having 1 to 3 carbon atoms, an alkyloxycarbonyl group having 2 to 3 carbon atoms, a cyano group, and a nitro group.
The bonding positions of the benzene ring in Ar ₁ and Ar _1′ , in which any hydrogen atom on the ring may be substituted, are preferably 1-position and 4-position, the bonding positions of the biphenyl structure in which any hydrogen atom on the ring may be substituted are preferably 4-position and 4-position, and the bonding positions of the naphthalene ring in Ar ₁ and Ar _1′, in which any hydrogen atom on the ring may be substituted, are preferably 2-position and 6-position.
Z represents a hydrogen atom or a monovalent organic group. Multiple Z's may be the same or different.

The specific diamine (B) is preferably a diamine represented by the following formulae (d _AL -1) to (d _AL -10), 1,7-bis(4-aminophenoxy)heptane, 1,7-bis(3-aminophenoxy)heptane, 1,8-bis(4-aminophenoxy)octane, 1,8-bis(3-aminophenoxy)octane, 1,9-bis(4-aminophenoxy)nonane, 1,9-bis(3-aminophenoxy)nonane, 1,10-bis(4-aminophenoxy)decane, 1,10-bis(3-aminophenoxy)decane, 1,11-bis(4 1,11-bis(3-aminophenoxy)undecane, 1,12-bis(4-aminophenoxy)dodecane, 1,12-bis(3-aminophenoxy)dodecane, 1,2-bis(6-amino-2-naphthyloxy)ethane, 1,4-bis(6-amino-2-naphthyloxy)butane, 1,2-bis(6-amino-2-naphthyl)ethane, or 6-[2-(4-aminophenoxy)ethoxy]-2-naphthylamine.

The polymer ( _PB ) is, for example, a polyimide precursor obtained by using a diamine component containing the specific diamine (B) or a polyimide which is an imidized product of the polyimide precursor. Here, examples of the polyimide precursor include, but are not limited to, polymers that can be imidized to obtain polyimide, such as polyamic acid and polyamic acid ester.

The polyamic acid (P _B ') which is a polyimide precursor of the polymer (P _B ) can be obtained by a polymerization reaction between a diamine component containing the specific diamine (B) and a tetracarboxylic acid component. The specific diamine (B) may be used alone or in combination of two or more.
The amount of the specific diamine (B) used is preferably 5 mol % or more, more preferably 10 mol % or more, and even more preferably 20 mol % or more, based on the total diamine components.

The diamine component used in the production of the polyamic acid (P _B ') may contain a diamine other than the specific diamine (B) (hereinafter also referred to as other diamine 2). When other diamine 2 is used in addition to the specific diamine (B), the amount of the specific diamine (B) used relative to the diamine component is preferably 90 mol % or less, more preferably 80 mol % or less.
In the case where the diamine component contains other diamine 2 and also contains the specific diamine (A), the amount of the specific diamine (A) used is less than 40 mol %, preferably less than 35 mol %, and more preferably less than 30 mol %.
In the case where the diamine component contains other diamine 2, does not contain the specific diamine (A), and contains the specific diamine (C) described below, the amount of the specific diamine (C) used is less than 30 mol %, and preferably less than 20 mol %.
A preferred specific example of the other diamine 2 is a diamine excluding the specific diamine (B) from the above other diamine 1. The other diamine 2 may be a diamine excluding the specific diamine (C) described below.

（Ｙは、窒素原子含有複素環及び基「＊２１－ＮＲ－＊２２」（＊２１、及び＊２２は、芳香族環を構成する炭素原子と結合する結合手を表す。
　但し、該炭素原子はＲが結合する窒素原子と環を形成しない。
　Ｒは水素原子又は１価の有機基を表し、上記１価の有機基はカルボニル炭素以外の炭素原子で窒素原子と結合する。）で表されるアミノ基からなる群から選ばれる窒素原子含有構造を有する２価の有機基を表す。
　Ｚは水素原子又は１価の有機基を表す。複数のＺは、互いに同一であってもよく、異なっていても良い。） <Polymer (C)>
The polymer (C) is a polymer (P C ) selected from the group consisting of polyimide precursors obtained using a diamine component containing 30 mol % or more of a diamine represented by the following formula (d _n ) (hereinafter also referred to as specific diamine ( _C )) based on the total diamine component, and polyimides which are imidized products of the polyimide precursors. The polymer (P _C ) may be one type or two or more types of polymers.
However, when a diamine other than the specific diamine (C) is contained as the diamine component, the specific diamine (A) is not contained.

(Y represents a nitrogen atom-containing heterocycle and a group "*21-NR-*22" (*21 and *22 represent bonds bonded to carbon atoms constituting the aromatic ring.
However, the carbon atom does not form a ring with the nitrogen atom to which R is bonded.
R represents a hydrogen atom or a monovalent organic group, and the monovalent organic group is bonded to the nitrogen atom at a carbon atom other than the carbonyl carbon.
Z represents a hydrogen atom or a monovalent organic group. Multiple Z's may be the same or different.

Examples of the nitrogen atom-containing heterocycle in the above formula (d _n ) include a pyrrole ring, imidazole ring, pyrazole ring, triazole ring, pyridine ring, pyrimidine ring, pyridazine ring, pyrazine ring, indole ring, benzimidazole ring, purine ring, quinoline ring, isoquinoline ring, naphthyridine ring, quinoxaline ring, phthalazine ring, triazine ring, carbazole ring, acridine ring, piperidine ring, piperazine ring, pyrrolidine ring, hexamethyleneimine ring, etc. Among these, a pyridine ring, a pyrimidine ring, a pyrazine ring, a piperidine ring, a piperazine ring, a quinoline ring, a carbazole ring, or an acridine ring is preferred.

Examples of the monovalent organic group represented by R in the above formula (d _n ) include alkyl groups such as methyl, ethyl, and propyl groups, alkenyl groups such as vinyl groups, cycloalkyl groups such as cyclohexyl groups, aryl groups such as phenyl and methylphenyl groups, and alkoxy groups (e.g., methoxy and ethoxy groups), etc. R is preferably a hydrogen atom or a methyl group.

Specific examples of the diamine represented by the above formula (d _n ) include 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 1,4-bis-(4-aminophenyl)-piperazine, 3,6-diaminoacridine, N-ethyl-3,6-diaminocarbazole, N-phenyl-3,6-diaminocarbazole, diamines represented by the following formula (d _n -1), and diamines represented by formulas (z-1) to (z-14).

In formula (d _n -1), m1 and m1' each independently represent an integer of 1 to 2. n1 is an integer of 1 to 3. _{R 1} has the same meaning as R in the amino group represented by the above "*21-NR-*22".
When a plurality of R _{1 s} and m1 's are present, the plurality of R 1 s and m1 's may be the same or different.

Preferred specific examples of the diamine represented by the above formula (d _n -1) include diamines represented by the following formulas (Dp-1) to (Dp-6).

The polymer (P _C ) is, for example, a polyimide precursor obtained by using a diamine component containing the specific diamine (C) or a polyimide which is an imidized product of the polyimide precursor. Here, examples of the polyimide precursor include, but are not limited to, polymers that can be imidized to obtain polyimide, such as polyamic acid and polyamic acid ester.

The polyamic acid (P _' ) which is a polyimide precursor of the polymer ( _P ') can be obtained by a polymerization reaction between a diamine component containing the specific diamine (C) and a tetracarboxylic acid component. The specific diamine (C) may be used alone or in combination of two or more.
The amount of the specific diamine (C) used is preferably 35 mol % or more, more preferably 40 mol % or more, and even more preferably 45 mol % or more, based on the total diamine components.

The diamine component used in the production of the polyamic acid (P _C ') may contain a diamine other than the specific diamine (C) (hereinafter also referred to as other diamine 3). When other diamine 3 is used in addition to the specific diamine (C), the amount of the specific diamine (C) used relative to the diamine component is preferably 90 mol % or less, more preferably 80 mol % or less.
When the other diamine 3 is contained as the diamine component, the specific diamine (A) is not contained.
Preferable specific examples of the other diamine 3 include the diamines obtained by excluding the specific diamine (C) from the above other diamine 1.
The other diamine 3 preferably contains a diamine having at least one group selected from the group consisting of a urea bond, an amide bond, a carboxy group, and a hydroxy group in the molecule, and at least one diamine selected from the group consisting of the specific diamine (B) (these are also referred to as specific diamine (c2) in the present invention). The diamine component may be a single diamine or a combination of two or more diamines.

When the polymer (B) and the following polymer (C) are contained as polymers other than the above polymer (A), a liquid crystal alignment film having a high voltage retention rate can be obtained even when a negative liquid crystal is used, and a liquid crystal alignment agent with excellent printability, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element using the liquid crystal alignment film can be obtained. Furthermore, a liquid crystal alignment agent that forms a liquid crystal alignment film that suppresses the occurrence of afterimages and exhibits low liquid crystal pretilt angle characteristics, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a high-performance liquid crystal display element equipped with the liquid crystal alignment film can be obtained.

The mechanism by which the above effect is obtained is not entirely clear, but it is presumed to be as follows. The specific diamine (A) has a repeating unit structure containing an alkylene chain and an oxygen atom, which increases the extensibility of the polymer (A), polymer (B) and polymer (C) when they are subjected to an orientation treatment, thereby obtaining high liquid crystal alignment, and thus the above effect is obtained.

(Tetracarboxylic acid components of polymer (P _B ) and polymer (P _C ))
When producing the polyamic acid (P _B ') or polyamic acid (P _C '), the tetracarboxylic acid component to be reacted with the diamine component may be not only a tetracarboxylic acid dianhydride but also a derivative of a tetracarboxylic acid dianhydride, such as a tetracarboxylic acid, a tetracarboxylic acid dihalide, a tetracarboxylic acid dialkyl ester, or a tetracarboxylic acid dialkyl ester dihalide.
Specific examples of the tetracarboxylic acid component used in the production of the polyamic acid (P _B ') or polyamic acid (P _{C '} ) include the acyclic aliphatic tetracarboxylic acid dianhydrides, alicyclic tetracarboxylic acid dianhydrides, aromatic tetracarboxylic acid dianhydrides, and derivatives thereof, which are exemplified for the polymer (P A '), including preferred specific examples.
The tetracarboxylic acid component used in the production of the polyamic acid (P _B ') or the polyamic acid (P _C ') more preferably contains a tetracarboxylic acid dianhydride 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, or a derivative thereof.
The amount of the tetracarboxylic acid derivative having the specific partial structure used is preferably 10 mol % or more _, more preferably 20 mol % or more, and even more preferably 50 mol % or more, based on the total amount of tetracarboxylic acid components used in the production of the polyamic acid (P B ') or polyamic acid (P _C ').

(Liquid crystal alignment agent)
The liquid crystal aligning agent of the present invention is, for example, a liquid composition obtained by dispersing or dissolving the polymer (A), a polymer other than the polymer (A), and other components used as necessary, preferably in a suitable solvent.
The total content of the polymers contained in the liquid crystal aligning agent of the present invention can be appropriately changed depending on the thickness of the coating film to be formed, but it is preferably 1% by mass or more from the viewpoint of forming a uniform and defect-free coating film, and is preferably 10% by mass or less from the viewpoint of storage stability of the solution. The particularly preferred total content of the polymers is 2 to 8% by mass.
When the liquid crystal aligning agent of the present invention contains the polymer (A), the polymer (B), and the polymer (C), the total content of the polymer (A), the polymer (B), and the polymer (C) is preferably 1 to 100 mass%, more preferably 10 to 100 mass%, and particularly preferably 20 to 100 mass%, based on the total content of the polymers contained in the liquid crystal aligning agent.

The content of the polymer (A) contained in the liquid crystal aligning agent of the present invention is 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the total content of the polymers other than the polymer (A).
The content of polymer (A) is preferably 0.5 parts by mass or more and 1.0 part by mass or more per 100 parts by mass of the total content of polymers other than polymer (A).
In the liquid crystal aligning agent of the present invention, when the polymer (B) and the polymer (C) are contained, the mass ratio of the polymer (C) to the content of the polymer (B) (the content of the polyimide precursor of the polymer (C)/the content of the polyimide precursor of the polymer (B)) is preferably 10/90 to 90/10, more preferably 20/80 to 90/10, and further preferably 20/80 to 80/20.

When the liquid crystal alignment agent of the present invention contains the polymer (A), the polymer (B), and the polymer (C), it may contain other polymers other than the polymers (P _A ) to (P _C ). Specific examples of other polymers include, in addition to the above-mentioned polymer (P), at least one polymer selected from the group consisting of polyimide precursors other than the polymers (P _A ) to (P _C ) and polyimides which are imidized products of the polyimide precursors, polysiloxanes, polyesters, polyamides, polyureas, 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 polymers selected from the group consisting of poly(meth)acrylates.

Specific examples of poly(styrene-maleic anhydride) copolymers include SMA1000, SMA2000, SMA3000 (manufactured by Cray Valley Corporation) and GSM301 (manufactured by Gifu Ceramics Manufacturing Co., Ltd.), and a specific example of poly(isobutylene-maleic anhydride) copolymers includes ISOBAM-600 (manufactured by Kuraray Co., Ltd.). A specific example of poly(vinyl ether-maleic anhydride) copolymers includes Gantrez AN-139 (methyl vinyl ether maleic anhydride resin, manufactured by Ashland Corporation).
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 10 to 90 parts by mass, and even more preferably 20 to 80 parts by mass, based on 100 parts by mass of the total of the polymers contained in the liquid crystal alignment agent.

(Production of polyamic acid)
The polyamic acid is produced by reacting a diamine component with a tetracarboxylic acid component in an organic solvent. The ratio of the tetracarboxylic acid component and the diamine component used in the reaction for producing the polyamic acid is preferably such that the acid anhydride group of the tetracarboxylic acid component is 0.5 to 2 equivalents, more preferably 0.8 to 1.2 equivalents, per equivalent of the amino group of the diamine component. As in the case of a normal polycondensation reaction, the closer the equivalent of the acid anhydride group of the tetracarboxylic acid component is to 1 equivalent, the higher the molecular weight of the polyamic acid produced.
The reaction temperature in the production of polyamic acid 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 production of polyamic acid can be carried out at any concentration, but the concentration of polyamic acid 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 of the reaction, and then a solvent can be added.

Specific examples of the organic solvent include cyclohexanone, cyclopentanone, 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 solubility in the solvent, solvents such as methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, 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 can be used.

(Production of polyamic acid ester)
The polyamic acid ester can be obtained by a known method such as, for example, [I] a method of reacting the polyamic acid obtained by the above-mentioned method with an esterifying agent, [II] a method of reacting a tetracarboxylic acid diester with a diamine, or [III] a method of reacting a tetracarboxylic acid diester dihalide with a diamine.

(Production of Polyimide)
Polyimide can be obtained by ring-closing (imidizing) a polyimide precursor such as the polyamic acid or polyamic acid ester. The imidization ratio in this specification refers to the ratio of imide groups to the total amount of imide groups derived from tetracarboxylic dianhydride or its derivatives and carboxyl groups (or their derivatives). The imidization ratio does not necessarily have to be 100% and can be adjusted as desired depending on the application or purpose.

Methods for imidizing the polyimide precursor include thermal imidization, in which a solution of the polyimide precursor is heated as is, and catalytic imidization, in which a catalyst is added to a solution of the polyimide precursor.
The temperature when thermally imidizing the polyimide precursor in a solution is preferably 100 to 400° C., more preferably 120 to 250° C., and it is preferable to carry out the imidization while removing water produced by the imidization reaction from the system.

Catalytic imidization of polyimide precursors can be carried out by adding a basic catalyst and an acid anhydride to a solution of the polyimide precursor and stirring at -20 to 250°C, preferably 0 to 180°C. The amount of the basic catalyst is 0.5 to 30 molar times, preferably 2 to 20 molar times, the amount of the amic acid group, and the amount of the acid anhydride is 1 to 50 molar times, preferably 3 to 30 molar times, the amount of the amic acid group. Examples of basic catalysts include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine, and among these, pyridine is preferred because it has a suitable basicity for promoting the reaction. Examples of acid anhydrides include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride, and among these, acetic anhydride is preferred because it makes purification after the reaction easy. The imidization rate by catalytic imidization can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

When recovering the polyimide precursor or polyimide produced from a reaction solution of a polyimide precursor or polyimide, the reaction solution may be poured into a solvent to cause precipitation. Examples of solvents used for precipitation include methanol, ethanol, isopropyl alcohol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water. The polymer precipitated by pouring into the solvent can be recovered by filtration, and then dried at room temperature or by heating under normal or reduced pressure. The recovered polymer can be redissolved in an organic solvent and reprecipitated and recovered 2 to 10 times to reduce the amount of impurities in the polymer. Examples of the solvent used in this case include alcohols, ketones, and hydrocarbons. Using three or more solvents selected from these is preferable because it further increases the efficiency of purification.

In producing the polyimide precursor or polyimide of the present invention, a terminal-capping polymer may be produced by using a tetracarboxylic acid component containing a tetracarboxylic dianhydride or a derivative thereof, and a diamine component containing the above-mentioned diamine, together with a suitable terminal-capping agent. The terminal-capping polymer has the effect of improving the film hardness of the alignment film obtained by coating and improving the adhesion property between the sealant and the alignment film.
Examples of the terminals of the polyimide precursor or polyimide in the present invention include an amino group, a carboxy group, an acid anhydride group, or a group derived from a terminal blocking agent described below. The amino group, the carboxy group, and the acid anhydride group can be obtained by a normal condensation reaction or by blocking the terminals with the terminal blocking agent described below.

Examples of the end-capping agent include acid anhydrides 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; dicarbonic acid diester compounds such as di-tert-butyl dicarbonate and diallyl dicarbonate; chlorocarbonyl compounds such as acryloyl chloride, methacryloyl chloride, and nicotinic acid chloride; and aniline. Examples of the isocyanate include monoamine compounds such as phosphorus, 2-aminophenol, 3-aminophenol, 4-aminosalicylic acid, 5-aminosalicylic acid, 6-aminosalicylic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, cyclohexylamine, n-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, and n-octylamine; and isocyanates having an unsaturated bond such as ethyl isocyanate, phenyl isocyanate, naphthyl isocyanate, or 2-acryloyloxyethyl isocyanate and 2-methacryloyloxyethyl isocyanate.
The proportion of the end-capping agent used is preferably 0.01 to 20 parts by mole, and more preferably 0.01 to 10 parts by mole, per 100 parts by mole of the total of the diamine components used.

The polystyrene-equivalent weight average molecular weight (Mw) of the polyimide precursor and polyimide measured by gel permeation chromatography (GPC) is preferably 1,000 to 500,000, more preferably 2,000 to 300,000, and even more preferably 10,000 to 50,000. The molecular weight distribution (Mw/Mn), expressed as the ratio of Mw to the polystyrene-equivalent number average molecular weight (Mn) measured by GPC, is preferably 15 or less, and more preferably 10 or less. Having the molecular weight within this range ensures good liquid crystal alignment in the liquid crystal display element.

The organic solvent contained in the liquid crystal alignment agent according to the present invention is not particularly limited as long as it dissolves the polymer (A) and polymers other than the polymer (A) uniformly. For example, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyllactamide, N,N-dimethylpropionamide, tetramethylurea, N,N-diethylformamide, N,N-diethylacetamide, 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,N-diol, methyl ethyl ketone ... Examples of the solvent include methylpropanamide, 3-butoxy-N,N-dimethylpropanamide, N-(n-propyl)-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-(n-butyl)-2-pyrrolidone, N-(t-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 to 99% by mass, more preferably 20 to 90% by mass, and particularly preferably 30 to 80% by mass, of the total solvent contained in the liquid crystal alignment agent.

The organic solvent contained in the liquid crystal alignment agent is preferably a mixed solvent that uses, in addition to the above-mentioned solvent, a solvent (also called a poor solvent) that improves the applicability when applying the liquid crystal alignment agent and the surface smoothness of the coating film. Specific examples of poor solvents are listed below, but are not limited to these. The content of the poor solvent is preferably 1 to 80 mass % of the total solvent contained in the liquid crystal alignment agent, more preferably 10 to 80 mass %, and particularly preferably 20 to 70 mass %. The type and content of the poor solvent are appropriately selected depending on the application device, application conditions, application environment, etc. of the liquid crystal alignment agent.

Examples of poor solvents include diisopropyl ether, diisobutyl ether, diisobutyl carbinol (2,6-dimethyl-4-heptanol), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-dibutoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, and 3-ethoxybutyl ether. acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, 1-(2-butoxyethoxy)-2-propanol, 2-(2-butoxyethoxy)-1 -propanol, propylene glycol monomethyl ether acetate, propylene 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 acetate, propylene glycol diacetate, Examples include 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, diisobutyl ketone (2,6-dimethyl-4-heptanone), (1S,5R)-6,8-dioxabicyclo[3.2.1]octan-4-one, etc.

Among these, 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, N,N-dimethyl lactamide and diisobutyl ketone, and N-methyl-2-pyrrolidone. and ethyl 3-ethoxypropionate, N-ethyl-2-pyrrolidone and ethyl 3-ethoxypropionate, N-methyl-2-pyrrolidone and ethyl 3-ethoxypropionate and dipropylene glycol monomethyl ether, 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 ether, N-ethyl-2-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 and diethylene glycol monoethyl ether and butyl cellosolve acetate, N-methyl-2-pyrrolidone and diethylene glycol monomethyl ether and butyl cellosolve acetate, N,N-dimethyl lactamide and diethylene glycol diethyl ether, N-methyl-2-pyrrolidone and γ-butyro Lactone and 4-hydroxy-4-methyl-2-pentanone and diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone and N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone, N-ethyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and propylene glycol monobutyl ether, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and diisobutyl ketone, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol monomethyl ether, N-methyl-2-pyrrolidone and 4-hydroxy-4-methyl-2-pentanone and dipropylene glycol monomethyl ether N-methyl-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, propylene glycol monobutyl ether, and dipropylene glycol monomethyl ether, N-ethyl-2-pyrrolidone, diethylene glycol diethyl ether, ethyl 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-2-pyrrolidone, ethylene glycol monobutyl ether and ethylene glycol monobutyl ether acetate, γ-butyrolactone and ethylene glycol monobutyl ether acetate Examples of such compounds include 4-hydroxy-4-methyl-2-pentanone, cyclohexyl acetate, and 4-hydroxy-4-methyl-2-pentanone, cyclohexanone and propylene glycol monomethyl ether, cyclopentanone and propylene glycol monomethyl ether, and N-methyl-2-pyrrolidone, cyclohexanone and propylene glycol monomethyl ether.

(Liquid crystal alignment agent)
The liquid crystal alignment agent of the present invention may contain other components (hereinafter also referred to as additive components) in addition to the above polymer (A), the polymer other than the above polymer (A), and the above organic solvent. Examples of such additive components include at least one crosslinking compound selected from the group consisting of a crosslinking compound having at least one substituent selected from an oxiranyl group, an oxetanyl group, a blocked isocyanate group, an oxazoline group, a cyclocarbonate group, a hydroxyl group, and an alkoxy group, and a crosslinking compound having a polymerizable unsaturated group, a functional silane compound, a metal chelate compound, a curing accelerator, a surfactant, an antioxidant, a sensitizer, a preservative, and a compound for adjusting the dielectric constant or electrical resistance of the resulting liquid crystal alignment film.

Specific preferred examples of the crosslinkable compound 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, 2,2-dibromoneopentyl glycol diglycidyl ether, 1,3,5,6-tetraglycidyl-2,4-hexanediol, bisphenol A type epoxy resins such as Epicoat (registered trademark) 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 biphenyl skeleton-containing epoxy resins such as YX6954BH30 (manufactured by Mitsubishi Chemical Corporation). 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 (registered trademark) (manufactured by Nissan Chemical Industries, Ltd.), alicyclic epoxy resins such as Celloxide (registered trademark) 2021P (manufactured by Daicel Chemical Industries, Ltd.), N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3- Compounds containing a tertiary nitrogen atom, such as bis(N,N-diglycidylaminomethyl)cyclohexane or N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane, and compounds having two or more oxiranyl groups, such as tetrakis(glycidyloxymethyl)methane; compounds having two or more oxetanyl groups, such as those described in paragraphs [0170] to [0175] of WO2011/132751; Coronate (registered trademark) A Compounds having a blocked isocyanate group, such as P Stable M, Coronate 2503, 2515, 2507, 2513, 2555, Millionate (registered trademark) MS-50 (all manufactured by Tosoh Corporation), Takenate (registered trademark) 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-oxo) compounds having an oxazoline group such as 2,2'-bis(5-methyl-2-oxazoline), 1,2,4-tris-(2-oxazolinyl-2)-benzene, and EPOCROS (registered trademark) (manufactured by Nippon Shokubai Co., Ltd.); compounds having a cyclocarbonate group described in paragraphs [0025] to [0030] and [0032] of WO2011/155577; n,n,n',n'-tetrakis(2-hydroxyethyl)adipamide, 2,2-bis(4-hydroxyethyl)adipamide, Compounds having a hydroxy group or an alkoxy group, such as 2,2-bis(4-hydroxy-3,5-dimethoxymethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dihydroxymethylphenyl)-1,1,1,3,3,3-hexafluoropropane; compounds represented by glycerin mono(meth)acrylate, glycerin di(meth)acrylate (1,2-,1,3-mixture), glycerin tris(meth)acrylate, glycerol 1,3-diglycerolate di(meth)acrylate, pentaerythritol tri(meth)acrylate, diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, pentaethylene glycol mono(meth)acrylate, and hexaethylene glycol mono(meth)acrylate.
The content of the crosslinkable compound is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, based on 100 parts by mass of the polymer component contained in the liquid crystal aligning agent.

The compound for adjusting the dielectric constant and electrical resistance may be 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 silane, 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-trimethoxysilylpropyl)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.

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 1 to 10 mass %.
A particularly preferred range of solid content concentration varies depending on the method used when applying the liquid crystal alignment agent to the substrate. For example, when using a spin coating method, it is particularly preferred that the solid content concentration is 1.5 to 4.5 mass%. When using a printing method, it is particularly preferred that the solid content concentration is 3 to 9 mass%, thereby making the solution viscosity 12 to 50 mPa·s. When using an inkjet method, it is particularly preferred that the solid content concentration is 1 to 5 mass%, thereby making the solution viscosity 3 to 15 mPa·s. The temperature when preparing the polymer composition is preferably 10 to 50°C, more preferably 20 to 30°C.

(Liquid crystal alignment film and liquid crystal display element)
The liquid crystal display element according to the present invention includes a liquid crystal alignment film formed using the above liquid crystal alignment agent. The operation mode of the liquid crystal display element is not particularly limited, and the liquid crystal display element can be applied to various operation modes, such as TN type, STN type, vertical alignment type (including VA-MVA type, VA-PVA type, etc.), in-plane switching type (IPS type, FFS type), optical compensation bend type (OCB type), etc.

The liquid crystal display element of the present invention can be manufactured, 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).

<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. Specific examples of step (1) are 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 type or FFS type 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.

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 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 steps 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 the polyamic acid, a baking step at, for example, 150 to 300°C or 150 to 250°C may be added after the above step. 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 the case of a horizontal alignment type liquid crystal display element such as an IPS mode or FFS mode, an alignment ability imparting treatment is performed on the coating film. On the other hand, in the case of a vertical alignment type liquid crystal display element such as a VA mode or PSA mode, the formed coating film can be used as a liquid crystal alignment film as it is, but the coating film may be subjected to an alignment ability imparting treatment. Examples of the alignment treatment method for the liquid crystal alignment film include a rubbing 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 polarized radiation in a certain direction, and, if necessary, a heat treatment is performed at a temperature of preferably 150 to 250° C. 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 preferably 100 to 400 nm, more preferably 200 to 400 nm, are used.

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.
Furthermore, the liquid crystal alignment film irradiated with polarized radiation by the above-mentioned method can be contact-treated with water or a solvent, or the liquid crystal alignment film irradiated with radiation can be heat-treated.

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-mentioned radiation is preferably 50 to 300°C, and even more preferably 120 to 250°C. The heat treatment time is preferably 1 to 30 minutes.

<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 a liquid crystal composition is placed 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 a predetermined number of 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 to contact 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 the substrate to a temperature at which the liquid crystal composition used has an isotropic phase and then slowly cooling to room temperature.
When the coating films are subjected to a rubbing treatment, the two substrates are disposed opposite 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 includes 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 can 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, 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 Co., Ltd., and NA-1559 manufactured by DIC Corporation.
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 equipped with electrodes, and is manufactured through a process in which a liquid crystal composition containing a polymerizable compound which is polymerized by at least one of active energy rays and heat is placed between the pair of substrates, and the polymerizable compound is polymerized 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 mode type liquid crystal display element) which has a liquid crystal layer between a pair of substrates equipped with 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 mode type liquid crystal display element>
A method of manufacturing a liquid crystal display element through a step of irradiating ultraviolet light as described below after the above-mentioned (4) 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 all the polymer components. The polymerizable group may be contained in a polymer used for a liquid crystal alignment agent, and an example of such a polymer is 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.

An IPS substrate, which is a comb-tooth electrode substrate used in the IPS mode, has 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.
The FFS substrate, which is a comb-tooth electrode substrate used in the FFS mode, has 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.

FIG. 1 is a schematic partial cross-sectional view showing an example of a horizontal electric field liquid crystal display element of the present invention, which is an example of an IPS mode liquid crystal display element.
In the in-plane switching liquid crystal display element 1 illustrated in Fig. 1, liquid crystal 3 is sandwiched between a comb-tooth electrode substrate 2 having a liquid crystal alignment film 2c and a counter substrate 4 having a liquid crystal alignment film 4a. The comb-tooth electrode substrate 2 has a base material 2a, a plurality of linear electrodes 2b formed on the base material 2a and arranged in a comb-tooth shape, and a liquid crystal alignment film 2c formed on the base material 2a so as to cover the linear electrodes 2b. The counter substrate 4 has a base material 4b and a liquid crystal alignment film 4a formed on the base material 4b. The liquid crystal alignment film 2c is, for example, the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4c is also the liquid crystal alignment film of the present invention.
In this IPS LCD element 1, when a voltage is applied to the linear electrodes 2b, an electric field is generated between the linear electrodes 2b as indicated by electric force lines L.

FIG. 2 is a schematic partial cross-sectional view showing another example of the in-plane switching liquid crystal display element of the present invention, which is an example of an FFS mode liquid crystal display element.
In the lateral electric field liquid crystal display element 1 illustrated in Fig. 2, liquid crystal 3 is sandwiched between a comb-tooth electrode substrate 2 having a liquid crystal alignment film 2h and a counter substrate 4 having a liquid crystal alignment film 4a. The comb-tooth electrode substrate 2 has a base material 2d, a plane electrode 2e formed on the base material 2d, an insulating film 2f formed on the plane electrode 2e, a plurality of linear electrodes 2g formed on the insulating film 2f and arranged in a comb-tooth shape, and a liquid crystal alignment film 2h formed on the insulating film 2f so as to cover the linear electrodes 2g. The counter substrate 4 has a base material 4b and a liquid crystal alignment film 4a formed on the base material 4b. The liquid crystal alignment film 2h is, for example, the liquid crystal alignment film of the present invention. The liquid crystal alignment film 4a is also the liquid crystal alignment film of the present invention.
In this IPS LCD element 1, when a voltage is applied to the plane electrodes 2e and the linear electrodes 2g, an electric field is generated between the plane electrodes 2e and the linear electrodes 2g as indicated by electric field lines L.

（ジアミン）
　ＤＡ－１～ＤＡ－８：それぞれ、下記式（ＤＡ－１）～（ＤＡ－８）で表される化合物

　上記ジアミンのうち、ＤＡ－１及びＤＡ－８は特定ジアミン（Ａ）の範囲に含まれる。ＤＡ－２及びＤＡ－６は特定ジアミン（Ｂ）の範囲に含まれる。ＤＡ－３は特定ジアミン（Ｃ）の範囲に含まれる。
（添加剤）
　ＡＤ－１～ＡＤ－２：それぞれ、下記式（ＡＤ－１）～（ＡＤ－２）で表される化合物

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The abbreviations of the compounds used and the methods for measuring the respective physical properties are as follows.
(Organic solvent)
NMP: N-methyl-2-pyrrolidone GBL: γ-butyrolactone BCS: Butyl cellosolve (tetracarboxylic dianhydride)
CA-1 to CA-4: Compounds represented by the following formulas (CA-1) to (CA-4), respectively.

(Diamine)
DA-1 to DA-8: Compounds represented by the following formulas (DA-1) to (DA-8), respectively.

Among the above diamines, DA-1 and DA-8 are included in the range of specific diamine (A). DA-2 and DA-6 are included in the range of specific diamine (B). DA-3 is included in the range of specific diamine (C).
(Additives)
AD-1 to AD-2: Compounds represented by the following formulas (AD-1) to (AD-2), respectively.

<Measurement of Viscosity>
The measurement was performed at 25° C. using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.) with a sample volume of 1.1 mL and a cone rotor TE-1 (1°34′, R24).

<Measurement of molecular weight>
Measurements were carried out using the following room temperature GPC (gel permeation chromatography) apparatus under the following conditions, and Mn and Mw were calculated as values calculated in terms of polyethylene glycol and polyethylene oxide.
GPC device: GPC-101 (Showa Denko K.K.),
Column: GPC KD-803 and GPC KD-805 (Showa Denko K.K.) in series;
Column temperature: 50 ° C.
Eluent: N,N-dimethylformamide (additives: lithium bromide monohydrate (LiBr.H ₂ O) 30 mmol/L, phosphoric acid anhydrous crystal (o-phosphoric acid) 30 mmol/L, tetrahydrofuran (THF) 10 mL/L),
Flow rate: 1.0 mL/min. Standard samples for preparing a calibration curve: TSK standard polyethylene oxide (molecular weight; about 900,000, about 150,000, about 100,000, and about 30,000) (manufactured by Tosoh Corporation) and polyethylene glycol (molecular weight; about 12,000, about 4,000, and about 1,000) (manufactured by Polymer Laboratory Co., Ltd.).

[Synthesis of Polymer]
<Synthesis Example 1>
DA-6 (2.29 g, 8.00 mmol) and NMP (16.8 g) were added to a 50 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature while feeding nitrogen. Thereafter, CA-1 (1.69 g, 7.54 mmol) and NMP (12.4 g) were added, and the mixture was stirred at 40° C. for 18 hours to obtain a solution of polyamic acid (A-1) with a solid content concentration of 12% by mass (viscosity: 225 mPa·s). The Mn of this polyamic acid was 10,382, and the Mw was 32,874.
<Synthesis Example 2>
DA-2 (0.977 g, 4.00 mmol), DA-3 (0.797 g, 4.00 mmol) and NMP (10.1 g) were added to a 50 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature while feeding nitrogen. Then, CA-2 (1.50 g, 6.00 mmol) and NMP (8.30 g) were added and stirred at 50 ° C. for 5 hours. Then, after cooling to room temperature, CA-3 (0.494 g, 1.68 mmol) and NMP (2.80 g) were added and stirred at 70 ° C. for 18 hours to obtain a solution of polyamic acid (A-2) with a solid content concentration of 15 mass% (viscosity: 304 mPa · s). The Mn of this polyamic acid was 9,284 and the Mw was 26,834.
<Synthesis Example 3>
DA-6 (9.74 g, 34.0 mmol), DA-4 (1.37 g, 4.01 mmol), DA-5 (1.11 g, 1.99 mmol) and NMP (106 g) were added to a 100 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature while feeding nitrogen. Thereafter, CA-1 (7.89 g, 35.2 mmol) and NMP (37.5 g) were added, and the mixture was stirred at room temperature for 18 hours to obtain a solution of polyamic acid (A-3) with a solid content concentration of 12% by mass (viscosity: 210 mPa s). The Mn of this polyamic acid was 10,521 and the Mw was 32,302.
<Synthesis Example 4>
DA-3 (3.11 g, 15.6 mmol), DA-2 (2.54 g, 10.4 mmol) and NMP (41.4 g) were added to a 100 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature while feeding nitrogen. Then, CA-2 (3.25 g, 13.0 mmol) and NMP (9.00 g) were added, and the mixture was stirred at 50 ° C. for 5 hours. Then, after cooling to room temperature, CA-3 (3.32 g, 11.3 mmol) and NMP (18.8 g) were added, and the mixture was stirred at 70 ° C. for 18 hours to obtain a solution of polyamic acid (A-4) with a solid content concentration of 15 mass% (viscosity: 296 mPa · s). The Mn of this polyamic acid was 9,081, and the Mw was 23,875.
<Synthesis Example 5>
DA-1 (1.87 g, 4.49 mmol) and NMP (13.7 g) were added to a 50 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature while feeding nitrogen. Then, CA-1 (0.500 g, 2.23 mmol) and NMP (3.70 g) were added, and the mixture was stirred at 40° C. for 18 hours to obtain a solution of polyamic acid (A-5) with a solid content concentration of 12% by mass (viscosity: 6 mPa·s). The Mn of this polyamic acid was 1,750 and the Mw was 2,158.
<Synthesis Example 6>
DA-1 (3.12 g, 7.49 mmol) and NMP (22.9 g) were added to a 50 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature while feeding nitrogen. Thereafter, CA-1 (1.60 g, 7.14 mmol) and NMP (10.8 g) were added, and the mixture was stirred at 40° C. for 18 hours to obtain a solution of polyamic acid (A-6) with a solid content concentration of 12% by mass (viscosity: 282 mPa·s). The Mn of this polyamic acid was 10,704, and the Mw was 39,144.
<Synthesis Example 7>
DA-3 (5.42 g, 27.2 mmol), DA-7 (1.35 g, 6.80 mmol) and NMP (64.5 g) were added to a 100 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature while feeding nitrogen. Thereafter, CA-4 (1.53 g, 7.82 mmol) and NMP (10.2 g) were added, and the mixture was stirred at room temperature for 30 minutes. Thereafter, the mixture was cooled to room temperature, and then CA-2 (6.38 g, 25.5 mmol) and NMP (8.50 g) were added, and the mixture was stirred at 50° C. for 15 hours to obtain a solution of polyamic acid (A-7) having a solid content concentration of 15% by mass (viscosity: 1,250 mPa·s). The Mn of this polyamic acid was 15,100, and the Mw was 54,900.
<Synthesis Example 8>
DA-8 (3.92 g, 7.00 mmol) and NMP (35.3 g) were added to a 50 mL four-neck flask equipped with a stirrer and a nitrogen inlet tube, and dissolved by stirring at room temperature while feeding nitrogen. Then, CA-1 (1.26 g, 5.60 mmol) and NMP (2.42 g) were added, and the mixture was stirred at 40° C. for 18 hours to obtain a solution of polyamic acid (A-8) with a solid content concentration of 12% by mass (viscosity: 35 mPa·s). The Mn of this polyamic acid was 3,734 and the Mw was 8,173.

The types and amounts of the tetracarboxylic acid components and diamine components used in Synthesis Examples 1 to 8 are shown in Table 1. In Table 1, the numbers in parentheses for the tetracarboxylic acid components and diamine components indicate the proportion (parts by mole) of each compound used relative to 100 parts by mole of the total amount of the diamine components used in the synthesis of each polyamic acid.
The polyamic acids A-1 and A-3 correspond to the polymer (B) of the present invention, the polyamic acids A-2, A-4, and A-7 correspond to the polymer (C) of the present invention, and the polyamic acids A-5 to A-6, and A-8 correspond to the polymer (A) of the present invention.

[Preparation of liquid crystal alignment agent]
Example 1
To the solution (1.22 g) of the polyamic acid (A-1) obtained in Synthesis Example 1, the solution (2.93 g) of the polyamic acid (A-2) obtained in Synthesis Example 2, the solution (0.15 g) of the polyamic acid (A-5) obtained in Synthesis Example 5, NMP (0.55 g), GBL (4.78 g), BCS (4.50 g), AD-1 (1 mass% GBL solution, 0.59 g), and AD-2 (10 mass% NMP solution, 0.29 g) were added, and the mixture was stirred at room temperature for 2 hours to obtain a liquid crystal aligning agent (AL-1) of the present invention.

<Examples 2 to 7 and Comparative Examples 1 to 5>
The liquid crystal alignment agents AL-2 to AL-7, which are the examples 2 to 7 of the present invention, and the liquid crystal alignment agents AL-C1 to AL-C5, which are the comparative examples 1 to 5, were obtained by the same operation as in Example 1, except that the type and amount of the polyamic acid solution and the solvent used were changed as shown in Table 2.

[Preparation of Liquid Crystal Cell]
<Preparation of Liquid Crystal Cell for Evaluation of Pretilt Angle and Voltage Holding Ratio>
First, a substrate with electrodes was prepared. The substrate was a glass substrate with a size of 30 mm x 40 mm and a thickness of 0.7 mm. An ITO electrode with a film thickness of 35 nm was formed on the substrate, and the electrodes were in a stripe pattern with an interval of 40 mm vertically and 10 mm horizontally.
Next, the liquid crystal alignment agent obtained above was filtered through a filter with a pore size of 1.0 μm, and then applied to the electrode-attached substrate prepared above by spin coating. Then, it was dried on a hot plate at 80 ° C. for 2 minutes, and then baked in an infrared heating furnace at 230 ° C. for 20 minutes to form a coating film with a thickness of 60 nm to obtain a substrate with a liquid crystal alignment film. This liquid crystal alignment film was subjected to a rubbing alignment treatment (roller diameter: 120 mm, roller rotation speed: 1000 rpm, moving speed: 20 mm / sec, indentation length: 0.4 mm) with a rayon cloth (HY-5318, manufactured by Hyperflex). Then, it was washed by ultrasonic irradiation in pure water for 1 minute, water droplets were removed by air blowing, and then it was dried at 80 ° C. for 10 minutes to obtain a substrate with a liquid crystal alignment film. Two substrates with this liquid crystal alignment film were prepared, and after dispersing spherical spacers with a particle size of 4 μm on the liquid crystal alignment film surface of one of them, a sealant (Mitsui Chemicals XN-1500T) was printed around the periphery, leaving a liquid crystal injection port, and the other substrate was attached so that the rubbing direction was in the opposite direction and the film surfaces faced each other. Then, a heat treatment was performed at 150°C for 60 minutes to harden the sealant and prepare an empty cell. Negative liquid crystal NA-1559 (DIC) was injected into this empty cell by a reduced pressure injection method, and the injection port was sealed to obtain a liquid crystal cell. The obtained liquid crystal cell was then heated at 120°C for 1 hour, left overnight at 23°C, and used for pretilt angle evaluation.

<Preparation of FFS Drive Liquid Crystal Cell>
A liquid crystal cell having the structure of an FFS mode liquid crystal display element was prepared.
First, a substrate with electrodes was prepared. The substrate was a rectangular glass substrate with dimensions 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 as a first layer, which constituted a common electrode. A SiN (silicon nitride) film formed by CVD (chemical vapor deposition) was formed as a second layer on the first common electrode. The thickness of the second SiN film was 300 nm, which was a thickness that functioned as an interlayer insulating film. A comb-shaped pixel electrode formed by patterning an ITO film as a third layer was arranged on the second SiN film, and two pixels, a first pixel and a second pixel, were formed, and the size of each pixel was 10 mm long and 5 mm wide. This substrate with electrodes had a structure in which the first common electrode and the third pixel electrode were insulated by the second SiN film.
The pixel electrode of the third layer had a comb-like shape with the central portion bent at an interior angle of 160° and multiple electrode lines, each 3 μm wide, arranged in parallel at intervals of 6 μm. One pixel was formed by multiple electrode lines and had a first region and a second region separated by a line connecting the bent portions.
Next, the liquid crystal alignment agent obtained above was filtered through a filter with a pore size of 1.0 μm, and then applied by spin coating to the electrode-attached substrate (hereinafter referred to as the electrode substrate) and a glass substrate (hereinafter referred to as the opposing substrate) having a columnar spacer with a height of 4 μm and an ITO film formed on the back surface. After drying for 2 minutes on a hot plate at 80 ° C., it was baked for 20 minutes in a hot air circulation oven at 230 ° C. to form a coating film with a thickness of 60 nm. This coating film was subjected to a rubbing alignment treatment (roller diameter: 120 mm, roller rotation speed: 1000 rpm, moving speed: 20 mm / sec, indentation length: 0.4 mm) with a rayon cloth (HY-5318, manufactured by Hyperflex). Thereafter, it was washed by ultrasonic irradiation in pure water for 1 minute, water droplets were removed by air blowing, and then it was dried for 10 minutes on a hot plate at 80 ° C. to obtain a substrate with a liquid crystal alignment film. The liquid crystal alignment film formed on the electrode substrate was subjected to an alignment treatment so that the direction that divides the inner angle of the pixel bend is parallel to the alignment direction of the liquid crystal, and the alignment film formed on the counter substrate was subjected to an alignment treatment so that the alignment direction of the liquid crystal on the electrode substrate coincides with the alignment direction of the liquid crystal on the counter substrate when the liquid crystal cell was produced. The above two substrates were combined into a set, and a sealant (Mitsui Chemicals XN-1500T) was printed on the substrate using a dispenser, and another substrate was attached to the set so that the alignment directions of the liquid crystal alignment films were 0° and faced each other. The attached substrates were then pressed together and heated for 60 minutes in a hot air circulation oven at 150°C to harden the sealant, producing an empty cell. Negative liquid crystal NA-1559 (DIC) was injected into this empty cell by a reduced pressure injection method, and the injection port was sealed to obtain an FFS drive liquid crystal cell. The obtained liquid crystal cell was then heated at 120°C for 1 hour and left at 23°C overnight before being used for evaluation.

[Evaluation of Liquid Crystal Cell Characteristics]
The characteristics of the liquid crystal cells for evaluating the pretilt angle and voltage holding ratio and the FFS driving liquid crystal cell prepared above were evaluated as follows.

<Measurement of pretilt angle>
The pretilt angle in the liquid crystal cell was measured by the Mueller matrix method using Axometrics' AxoScan. The lower the pretilt angle, the better the viewing angle characteristics. As the evaluation criteria, a pretilt angle of 2.10° or less was marked as "○", and a pretilt angle of more than 2.10° was marked as "×".

<Evaluation of alignment stability by long-term AC driving>
This evaluation is for evaluating image retention (also called AC image retention) that occurs due to deterioration of the alignment performance of a liquid crystal alignment film during long-term AC driving.
Using the FFS drive liquid crystal cell prepared above, an AC voltage of ±6.5V was applied at a frequency of 30 Hz for 120 hours on a high-luminance backlight (light source: LED, luminance: 30,000 cd/m ² ) with a surface temperature of 50° C. Then, the pixel electrode and the common electrode of the liquid crystal cell were shorted, and the cell was left at room temperature (23° C.) for one day. After the cell was left, the 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 without applying a voltage. The arrangement angle of the liquid crystal cell was adjusted so that the transmitted light intensity of the first region of the first pixel was minimized, and the rotation angle required when the liquid crystal cell was rotated so that the transmitted light intensity of the second region of the first pixel was minimized was calculated as the angle Δ. Similarly, the first region and the second region of the second pixel were compared, and the same angle Δ was calculated. Then, the average value of the angles Δ of the first pixel and the second pixel was calculated as the rotation angle Δ of the liquid crystal cell. It can be said that the stability of the liquid crystal alignment is better as the value of this rotation angle Δ is smaller. As the evaluation standard, an angle Δ of 0.25° or less was rated as "◯", and an angle Δ of more than 0.25° was rated as "×".

<Evaluation of voltage holding ratio after backlight durability test>
The liquid crystal cell for evaluating the voltage holding ratio was left for 96 hours under irradiation of a high-luminance backlight (light source: LED, luminance: 30,000 cd/ ^m2 ) with a surface temperature of 50°C. A voltage of 1V was then applied to the liquid crystal cell for 60 μsec at a temperature of 60°C, and the voltage after 167 msec was measured to calculate the voltage holding ratio, which indicates how much voltage was being held. The higher the voltage holding ratio, the better. It is known that an increase in the voltage holding ratio, which is one of the electrical properties of a liquid crystal display element, makes it less likely that line burn-in, which is one of the display defects of a liquid crystal display element, will occur.

[Evaluation of Coatability]
The liquid crystal alignment agent obtained above was applied by spin coating to an ITO substrate having a size of 100 mm x 100 mm and a thickness of 1.1 mm. After drying for 2 minutes on a hot plate at 80°C, it was baked for 20 minutes in a hot air circulation oven at 230°C to obtain a substrate with a liquid crystal alignment film having a thickness of 60 nm. When the substrate with the liquid crystal alignment film was observed with the naked eye, if the coating surface was uniform and free of unevenness, it was marked as "○", and if unevenness was visible on the coating surface, it was marked as "×".

Table 3 shows the evaluation results of the pretilt angle, afterimage characteristics, voltage holding ratio and coatability of the liquid crystal cells using the liquid crystal alignment agents of Examples 1 to 7 and Comparative Examples 1 to 5.
In Table 3, the numerical values in parentheses for the polymers indicate the blending ratio (parts by mass) of each polymer (solid content) when the total content of the polymers (solid content) other than polymer (A) is 100 parts by mass.

As shown in Table 3, the liquid crystal display element using the liquid crystal aligning agent of the present invention was excellent not only in viewing angle characteristics, afterimage characteristics and voltage holding ratio but also in coatability.
As shown in Table 3, the liquid crystal display element using the liquid crystal alignment agent of the present invention had a better voltage retention rate than the liquid crystal display element using the liquid crystal alignment agent not containing the polymer (A). For example, this is clear from the comparison between Example 1 and Comparative Example 3, the comparison between Examples 2 to 3 and Comparative Example 4, or the comparison between Example 5 and Comparative Example 5.

The liquid crystal alignment film obtained from the liquid crystal alignment agent of the present invention is widely used in liquid crystal display elements of various operation modes, but can also be used, for example, as a liquid crystal alignment film for retardation films, liquid crystal alignment films for scanning antennas and liquid crystal array antennas, or liquid crystal alignment films for transmissive scattering type liquid crystal dimming elements.

The liquid crystal display element of the present invention can be effectively applied to devices with various functions, such as liquid crystal televisions, clocks, portable games, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, and information displays.

1: In-plane electric field liquid crystal display element, 2: Comb-tooth electrode substrate, 2a, 4b, 2d: Base material, 2b, 2g: Linear electrodes, 2c, 2h, 4a: Liquid crystal alignment film, 2e: Planar electrodes, 2f: Insulating film, 3: Liquid crystal, 4: Counter substrate, L: Electric field lines

The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2023-175168, filed on October 10, 2023, are hereby incorporated by reference as the disclosure of the specification of the present invention.

Claims (12)

A liquid crystal aligning agent containing the following polymer (A) and a polymer other than the polymer (A),
The liquid crystal aligning agent, wherein the content of the polymer (A) is 0.1 parts by mass or more and 10 parts by mass or less, based on 100 parts by mass of the total content of the polymers other than the polymer (A).
Polymer (A): A polymer (P A ) selected from the group consisting of a polyimide precursor obtained using a tetracarboxylic acid derivative component containing an alicyclic tetracarboxylic acid dianhydride and a diamine component containing 40 mol % or more of a diamine ( _A ) represented by the following formula (D _A ) based on the total diamine component, and a polyimide which is an imidized product of the polyimide precursor:
Z-NH-Ar ₁ -X ₁ -(R ₁ -L) _n -R ₂ -X ₂ -Ar ₂ -NH-Z (D _A )
In formula (D _A ), Ar ₁ and Ar ₂ each independently represent a divalent aromatic group which is a divalent benzene ring, a biphenyl structure, or a naphthalene ring, and any hydrogen atom of the aromatic group may be replaced with a monovalent group.
X ₁ and X ₂ each independently represent a single bond, —O—, or *1-O—CO— (*1 represents a bond to Ar ₁ or Ar ₂ ).
R ₁ and R ₂ are each independently a divalent hydrocarbon group, and some of the hydrogen atoms in the divalent hydrocarbon group may be substituted with halogen atoms, methyl groups, trifluoromethyl groups, or hydroxy groups. Multiple R _1s may be the same or different.
L represents -O-, -C(=O)-, -O-C(=O)- or -C(=O)-O-. When a plurality of L's are present, the plurality of L's may be the same or different, provided that at least one L represents -O-C(=O)- or -C(=O)-O-. n represents an integer of 1 to 6.
Z represents a hydrogen atom or a monovalent organic group. Multiple Z's may be the same or different. The liquid crystal aligning agent according to claim 1 , wherein the polymer other than the polymer (A) contains the following polymer (B) and/or the following polymer (C).
Polymer (B): A polymer (P B ) selected from the group consisting of a polyimide precursor obtained by using a diamine component containing a diamine (B) represented by the following formula (d _AL ) (excluding those included in the diamine ( _A )) and a polyimide which is an imidized product of the polyimide precursor.
However, when the diamine component contains a diamine other than the diamine (B) and also contains the diamine (A), the amount of the diamine (A) used is less than 40 mol % based on the diamine component. Also, when the diamine component contains a diamine other than the diamine (B), does not contain the diamine (A), and contains the following diamine (C), the amount of the diamine (C) used is less than 30 mol % based on the total diamine component.

(Ar ₁ and Ar _1′ each represent a benzene ring, a biphenyl structure, or a naphthalene ring, and one or more hydrogen atoms on the benzene ring, the biphenyl structure, or the naphthalene ring may be substituted with a monovalent group.
_L1 and L1 _' each represent a single bond, -O-, -C(=O)-, or -O-C(=O)-. A represents _-CH2- , an alkylene group having 2 to 12 carbon atoms, or a divalent organic group in which at least one of -O-, -C(=O)-O-, and -O-C(=O)- is inserted between the carbon-carbon bonds of the alkylene group. Any hydrogen atom possessed by A may be substituted with a halogen atom.
However, when L ₁ and L _1′ in formula (d _AL ) are —O—, A represents —CH ₂ —, an alkylene group having 2 to 12 carbon atoms, or a divalent organic group in which —O— is inserted between the carbon-carbon bonds of the alkylene group.
One or more hydrogen atoms on the benzene ring, biphenyl structure, or naphthalene ring may be substituted with a monovalent group. Examples of the monovalent group include a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, a fluoroalkenyl group having 2 to 3 carbon atoms, a fluoroalkoxy group having 1 to 3 carbon atoms, an alkyloxycarbonyl group having 2 to 3 carbon atoms, a cyano group, and a nitro group.
Z represents a hydrogen atom or a monovalent organic group. Multiple Z's may be the same or different.
Polymer (C): A polymer (P C ) selected from the group consisting of polyimide precursors obtained using a diamine component containing 30 mol % or more of diamine ( _C ) represented by the following formula (d _n ) based on the total diamine component, and polyimides which are imidized products of the polyimide precursors.
However, when a diamine other than the diamine (C) is contained as the diamine component, the diamine (A) is not contained.

(Y represents a nitrogen atom-containing heterocycle and a group "*21-NR-*22" (*21 and *22 represent bonds bonded to carbon atoms constituting the aromatic ring.
However, the carbon atom does not form a ring with the nitrogen atom to which R is bonded.
R represents a hydrogen atom or a monovalent organic group, and the monovalent organic group is bonded to the nitrogen atom at a carbon atom other than the carbonyl carbon.
Z represents a hydrogen atom or a monovalent organic group. Multiple Z's may be the same or different. The liquid crystal alignment agent according to claim 2, wherein the polymer other than the polymer (A) contains the polymer (B) and the polymer (C). 2. The liquid crystal aligning agent according to claim 1, wherein the group "-(R ₁ -L) _n -R ₂ -" in the formula (D _A ) is selected from the following structures:
*-(CH ₂ ) _p -O-C(=O)-(CH ₂ ) _q -C(=O)-O-(CH ₂ ) _r -*,
*-(CH ₂ ) _p -C(=O)-O-(CH ₂ ) _q -O-C(=O)-(CH ₂ ) _r -*,
*-(CH ₂ ) _n1 -O-C(=O)-(CH ₂ ) _n2 -C(=O)-O-(CH ₂ ) _n3 -O-C(=O)-(CH ₂ ) _n4 -C(=O)-O-(CH ₂ ) _n5 -*;
*-(CH ₂ ) _n1 -C(=O)-O-(CH ₂ ) _n2 -O-C(=O)-(CH ₂ ) _n3 -C(=O)-O-(CH ₂ ) _n4 -O-C(=O)-(CH ₂ ) _n5 -*;
In the above, p, q, and r each independently represent an integer of 1 to 6.
n1 to n5 each independently represents an integer of 1 to 6, provided that the total number of carbon atoms in n1 to n5 is 20 or less.
* represents a bond. The liquid crystal aligning agent according to claim 1, wherein the diamine (A) is any diamine selected from the group consisting of the following formulae (d _A -1) to (d _A -10):

(In the formulae (d _A -1) to (d _A -10), the hydrogen atoms on the benzene rings may be substituted with monovalent substituents. p, q, r, and n1 to n5 are the same as those defined above.) The liquid crystal aligning agent according to claim 2, wherein the polymer (B) is obtained by a polycondensation reaction between the diamine component and a tetracarboxylic acid component containing an acyclic aliphatic tetracarboxylic acid dianhydride, an alicyclic tetracarboxylic acid dianhydride, an aromatic tetracarboxylic acid dianhydride, or a derivative thereof. The liquid crystal aligning agent according to claim 2, wherein the polymer (C) is obtained by a polycondensation reaction between the diamine component and a tetracarboxylic acid component containing an acyclic aliphatic tetracarboxylic acid dianhydride, an alicyclic tetracarboxylic acid dianhydride, an aromatic tetracarboxylic acid dianhydride, or a derivative thereof. The liquid crystal alignment agent according to claim 1, further comprising at least one crosslinking compound selected from the group consisting of crosslinking compounds having at least one substituent selected from an oxiranyl group, an oxetanyl group, a blocked isocyanate group, an oxazoline group, a cyclocarbonate group, a hydroxyl group, and an alkoxy group, and crosslinking compounds having a polymerizable unsaturated group, a functional silane compound, a metal chelate compound, a curing accelerator, a surfactant, an antioxidant, a sensitizer, a preservative, and an additive component selected from a compound for adjusting the dielectric constant and electrical resistance of the resulting liquid crystal alignment film. A liquid crystal alignment film obtained from the liquid crystal alignment agent according to any one of claims 1 to 8. A liquid crystal display element comprising the liquid crystal alignment film according to claim 9. The liquid crystal display element according to claim 10, which is a horizontal electric field liquid crystal display element. A method for manufacturing a liquid crystal display element, comprising the following steps (1) to (3):
Step (1): A step of applying the liquid crystal alignment agent according to any one of claims 1 to 8 onto a substrate; Step (2): A step of baking the applied liquid crystal alignment agent to obtain a film; Step (3): A step of performing an alignment treatment on the film obtained in step (2).

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