JP7582304B2 - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal display element - Google Patents

Description

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 element having the liquid crystal alignment film.

Conventionally, various driving methods have been developed for liquid crystal display elements, which differ in electrode structure and physical properties of the liquid crystal molecules used. For example, various display elements such as TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, VA (Vertical Alignment) type, IPS (In-Plane Switching) type, and FFS (fringe field switching) type are known.
A liquid crystal display element is generally constructed by arranging a pair of electrode substrates facing each other with a predetermined gap (several μm) and sealing liquid crystal between the electrode substrates. Display on the liquid crystal display element is performed by applying a voltage between the transparent conductive films constituting the electrodes of the electrode substrates. In addition, these liquid crystal display elements have a liquid crystal alignment film for orienting the liquid crystal molecules. Known materials for the liquid crystal alignment film include, for example, polyamic acid (polyamic acid), polyamic acid ester, polyimide, etc. (see Patent Document 1, etc.).

International Publication No. 2016-080458

The transparent conductive film in the liquid crystal display element is usually formed of a composition (ITO) in which indium oxide is the main component and several percent of tin oxide is doped therein, but the refractive index of the film is different from that of the liquid crystal alignment film and has a high value. Therefore, when light from a display light source is transmitted through the electrode substrate, the light is reflected at the interface between the transparent conductive film and the liquid crystal alignment film in each electrode substrate. As a result, the light transmittance of the electrode substrate cannot be sufficiently obtained, leading to a problem of a decrease in display brightness.
In particular, ultra-high definition panels such as 4K and 8K have been developed in recent years, but in these panels the occupancy rate of the black matrix (BM) and TFTs increases, reducing the aperture ratio of the panel, so improving the transmittance of the display area is becoming important.

Therefore, the inventors of the present invention have investigated various materials for increasing the refractive index of the liquid crystal alignment film, from the viewpoint that the above-mentioned problems can be eliminated by reducing the difference between the refractive index of the transparent conductive film and the refractive index of the liquid crystal alignment film. Specifically, in order to increase the refractive index of the liquid crystal alignment film, various types of polymers to be contained in the liquid crystal alignment agent that forms the liquid crystal alignment film were explored.

As a result, by selecting a specific polymer, it was possible to obtain a liquid crystal alignment film with a high refractive index close to that of the transparent conductive film, but on the other hand, it became clear that the polymers that form liquid crystal alignment films with high refractive indexes often have coloration properties. A liquid crystal alignment film formed from a liquid crystal alignment agent containing a coloration polymer therefore has a reduced light transmittance, leading to a decrease in display brightness, and as a result the above-mentioned objective is not achieved. In addition, it became clear that it is difficult to obtain a high refractive index for a liquid crystal alignment film with high vertical alignment properties due to the influence of the side chain structure, and a liquid crystal alignment film with both a high refractive index and vertical alignment properties was desired.

In view of the above circumstances, the object of the present invention is to provide a liquid crystal alignment agent that forms a liquid crystal alignment film having a high refractive index but no coloring and therefore high light transmittance, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film. Furthermore, the object of the present invention is to provide a liquid crystal alignment agent that forms a liquid crystal alignment film having high vertical alignment properties in addition to the above characteristics, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element having 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, and thus completed the present invention.

（式（２）～（１２）の芳香環上の任意の水素原子は置換されてもよく、
Ｒ^１２は、水素原子または炭素数１～１０のアルキル基を表し、
Ｗ¹およびＷ²は、互いに独立して、単結合、－ＣＲ⁹⁵Ｒ⁹⁶－（Ｒ⁹⁵およびＲ⁹⁶は、互いに独立して、水素原子または炭素数１～１０のアルキル基（ただし、これらは一緒になって環を形成していてもよい。）を表す。）、－Ｃ（＝Ｏ）－、－Ｏ－、－Ｓ－、－Ｓ（＝Ｏ）－、－ＳＯ₂－、または－ＮＲ⁹⁷－（Ｒ⁹⁷は、水素原子、炭素数１～１０のアルキル基又はフェニル基を表す。）を表し、
Ｘ¹およびＸ²は、互いに独立して、単結合、炭素数１～１０のアルキレン基、または－Ｙ_１－Ｐｈ－Ｙ_２－（Ｐｈはフェニレン基を表し、フェニレン基上の任意の水素原子は置換されてもよく、Ｙ₁およびＹ₂は、互いに独立して、単結合または炭素数１～１０のアルキレン基を表す。）で示される基を表す。） The present invention includes the following aspects.
[1] A liquid crystal aligning agent comprising the following components (A) and (B):
Component (A): At least one polymer (A) selected from the group consisting of polyimide precursors and polyimides which are imidized products of the polyimide precursors.
Component (B): A polymer (B) comprising a repeating unit structure represented by the following formula (1), having at least one triazine ring terminal, at least a portion of which is blocked with an arylamino group having a crosslinking group:
(R and R′ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or an aralkyl group;
Ar represents at least one selected from the group represented by formulas (2) to (12).

(Any hydrogen atom on the aromatic ring of formulas (2) to (12) may be substituted,
R ¹² represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms;
W ¹ and W ² each independently represent a single bond, -CR ⁹⁵ R ⁹⁶ - (R ⁹⁵ and R ⁹⁶ each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms (which may be joined together to form a ring)), -C(=O)-, -O-, -S-, -S(=O)-, -SO ₂ -, or -NR ⁹⁷ - (R ⁹⁷ represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a phenyl group);
^X1 and ^X2 each independently represent a single bond, an alkylene group having 1 to 10 carbon atoms, or a group represented by _-Y1 -Ph- _Y2- (Ph represents a phenylene group, any hydrogen atom on the phenylene group may be substituted, and _Y1 and _Y2 each independently represent a single bond or an alkylene group having 1 to 10 carbon atoms).

According to the present invention, it is possible to provide a liquid crystal alignment agent that forms a liquid crystal alignment film having a high refractive index but no coloring and therefore high light transmittance, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film. Furthermore, it is possible to provide a liquid crystal alignment agent that forms a liquid crystal alignment film having high vertical alignment properties in addition to the above characteristics, a liquid crystal alignment film obtained from the liquid crystal alignment agent, and a liquid crystal display element having the liquid crystal alignment film.

1 is a graph showing the results of measuring the ¹ H-NMR spectrum of compound T-1 synthesized in an example. 1 is a graph showing the measurement results of the ¹ H-NMR spectrum of compound T-2 synthesized in an example.

The liquid crystal alignment agent of the present invention, the liquid crystal alignment film obtained from the liquid crystal alignment agent, and the liquid crystal display element having the liquid crystal alignment film are described in detail below. However, the explanation of the constituent elements described below is an example of one embodiment of the present invention, and is not limited to these contents.

(Liquid crystal alignment agent)
The liquid crystal aligning agent of the present invention contains the following components (A) and (B).
Component (A): At least one polymer (A) selected from the group consisting of polyimide precursors and polyimides which are imidized products of the polyimide precursors.
Component (B): A polymer (B) containing a repeating unit structure represented by the above formula (1), having at least one triazine ring terminal, and at least a portion of the triazine ring terminal being blocked with an arylamino group having a crosslinking group.
The polymer (A) which is the component (A) and the polymer (B) which is the component (B) will each be described in detail below.

<Polymer (A)>
The liquid crystal aligning agent of the present invention contains at least one polymer (A) selected from the group consisting of polyimide precursors and polyimides which are imidized products of the polyimide precursors. The polymer constituting component (A) may be composed of one type or two or more types of polymers.
Examples of the polyimide precursor include polyamic acid, polyamic acid ester, and polyamic acid-polyamic acid ester copolymer, and the polyimide precursor is preferably obtained by polymerizing a diamine component and a tetracarboxylic acid component.

<<Diamine component>>
The diamine component may be at least one diamine (a) selected from the group consisting of structures represented by the following formulas (S1) to (S3): p-phenylenediamine, m-phenylenediamine, 4-(2-(methylamino)ethyl)aniline, 2,4-diaminobenzoic acid, 2,5-diaminobenzoic acid, 3,5-diaminobenzoic acid, or diamine compounds represented by the following formulas (3b-1) to (3b-4), each of which has a carboxyl group; 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 1,2-bis(4-aminophenyl)ethane, 1,3-bis(4-aminophenyl)propane, 1,4-bis(4-aminophenyl)propane, 1,5-bis(4-aminophenyl)propane, 1,6-bis(4-aminophenyl)propane, 1,7-bis(4-aminophenyl)propane, 1,8-bis(4-aminophenyl)propane, 1,9-bis(4-aminophenyl)propane, 2,10-bis(4-aminophenyl)propane, 2,11-bis(4-aminophenyl)propane, 2,2-bis(4-aminophenyl)propane, 2,3-bis(4-aminophenyl)propane, 2,4-bis(4-aminophenyl)propane, 2,5-bis(4-aminophenyl)propane, 2,6-bis(4-aminophenyl)propane, 2,2-bis(4-aminophenyl)propane, 2,3-bis(4-aminophenyl)propane, 2,4-bis(4-aminophenyl)propane, 2,5-bis(4-aminophenyl)propane, 2,5-bis(4-aminophenyl)propane, 2,6-bis(4-aminophenyl)propane, 2,5-bis(4-aminophenyl) phenyl)butane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,2-bis(4-aminophenoxy)ethane, 1,2-bis(4-amino-2-methylphenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,4-bis(4-aminophenoxy)butane, 1,5-bis(4-aminophenoxy)pentane, 1,6-bis(4-aminophenoxy)hexane, 4-(2-(4-aminophenoxy)ethoxy)-3-fluoroaniline, di(2-(4-aminophenoxy)ethyl)ether, 4-amino-4'-(2-(4-aminophenoxy)ethoxy)biphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl diamines having a urea bond such as 4,4'-diaminobiphenyl, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,7-diaminonaphthalene, 2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 2,2'-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 2,2'-bis(4-aminophenyl)propane, and 1,3-bis(4-aminophenethyl)urea; diamines having a photopolymerizable group at the terminal such as 2-(2,4-diaminophenoxy)ethyl methacrylate and 2,4-diamino-N,N-diallylaniline; radicals such as those represented by the following formulae (R1) to (R5). diamines having a polymerization initiation function, diamines having a photosensitizing function that exhibits a sensitizing effect upon irradiation with light, such as 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, and 9,9-bis(4-aminophenyl)fluorene; 2,6-diaminopyridine, 3,4-diaminopyridine, 2,4-diaminopyrimidine, 3,6-diaminocarbazole, N-methyl-3,6-diaminocarbazole; diamines having a heterocycle, such as those represented by the following formulae (z-1) to (z-18); diamines having a diphenylamine skeleton, such as those represented by the following formulae (Dp-1) to (Dp-9); and groups "-N(D)-" represented by the following formulae (5-1) to (5-10) (D represents a protecting group which is eliminated by heating and replaced with a hydrogen atom, and is preferably a tert-butoxycarbonyl group). Examples of the diamine component include, but are not limited to, aromatic diamines such as diamines having an oxazoline structure represented by the following formulae (Ox-1) to (Ox-2). The diamine component may be composed of one or more kinds of diamines.

（Ｘ^１及びＸ^２は、それぞれ独立して、単結合、－（ＣＨ_２）_ａ－（ａは１～１５の整数である。）、－ＣＯＮＨ－、－ＮＨＣＯ－、－ＣＯＮ（ＣＨ_３）－、－ＮＨ－、－Ｏ－、－ＣＯＯ－、－ＯＣＯ－又は－（（ＣＨ_２）_ａ１－Ａ_１）_ｍ１－（ａ１は１～１５の整数であり、Ａ_１は酸素原子又は－ＣＯＯ－を表し、ｍ_１は１～２の整数である。ｍ_１が２の場合、複数のａ１及びＡ_１は、それぞれ独立して上記定義を有する。）を表す。Ｇ^１及びＧ^２は、それぞれ独立して、炭素数６～１２の２価の芳香族基及び炭素数３～８の２価の脂環式基から選ばれる２価の環状基を表す。前記環状基上の任意の水素原子は、炭素数１～３のアルキル基、炭素数１～３のアルコキシル基、炭素数１～３のフッ素原子含有アルキル基、炭素数１～３のフッ素原子含有アルコキシ基又はフッ素原子で置換されていてもよい。ｍ及びｎはそれぞれ独立して０～３の整数であって、ｍ＋ｎは１～６の整数、好ましくは、１～４の整数である。Ｒ^１は炭素数１～２０のアルキル基、炭素数１～２０のアルコキシ基又は炭素数２～２０のアルコキシアルキル基を表し、Ｒ^１を形成する任意の水素原子はフッ素原子で置換されていてもよい。）

( ^X1 and ^X2 each independently represent a single bond, -( _CH2 ) _a- (a is an integer of 1 to 15), -CONH-, -NHCO-, -CON( _CH3 )-, -NH-, -O-, -COO-, -OCO-, or -(( _CH2 ) _a1 - _A1 ) _m1- (a1 is an integer of 1 to 15, _A1 represents an oxygen atom or -COO-, and _m1 is an integer of 1 to 2. When _m1 is 2, a1 and _A1 each independently have the above definition). ^G1 and G Each of ² independently represents a divalent cyclic group selected from a divalent aromatic group having 6 to 12 carbon atoms and a divalent alicyclic group having 3 to 8 carbon atoms. Any hydrogen atom on the cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, a fluorine atom-containing alkyl group having 1 to 3 carbon atoms, a fluorine atom-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. Each of m and n independently represents an integer of 0 to 3, and m+n is an integer of 1 to 6, preferably an integer of 1 to 4. ^{R 1} represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms, and any hydrogen atom forming R ¹ may be substituted with a fluorine atom.

( ^X3 represents a single bond, -CONH-, -NHCO-, -CON( _CH3 )-, -NH-, -O-, _-CH2O- , -COO- or -OCO-. ^R2 represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms, and any hydrogen atom forming ^R2 may be substituted with a fluorine atom.)

( ^X4 represents -CONH-, -NHCO-, -O-, -CH ₂ O-, -COO- or -OCO-. ^R3 represents a structure having a steroid skeleton.)

（式（３ｂ－１）中、Ａ^１は単結合、－ＣＨ_２－、－Ｃ_２Ｈ_４－、－Ｃ（ＣＨ_３）_２－、－ＣＦ_２－、－Ｃ（ＣＦ_３）_２－、－Ｏ－、－ＣＯ－、－ＮＨ－、－Ｎ（ＣＨ_３）－、－ＣＯＮＨ－、－ＮＨＣＯ－、－ＣＨ_２Ｏ－、－ＯＣＨ_２－、－ＣＯＯ－、－ＯＣＯ－、－ＣＯＮ（ＣＨ_３）－又は－Ｎ（ＣＨ_３）ＣＯ－を表し、ｍ１及びｍ２はそれぞれ独立して、０～４の整数であり、かつｍ１＋ｍ２は１～４の整数である。式（３ｂ－２）中、ｍ３及びｍ４はそれぞれ独立して、１～５の整数である。式（３ｂ－３）中、Ａ^２は炭素数１～５の直鎖又は分岐アルキル基を表し、ｍ５は１～５の整数である。式（３ｂ－４）中、Ａ^３及びＡ^４はそれぞれ独立して、単結合、－ＣＨ_２－、－Ｃ_２Ｈ_４－、－Ｃ（ＣＨ_３）_２－、－ＣＦ_２－、－Ｃ（ＣＦ_３）_２－、－Ｏ－、－ＣＯ－、－ＮＨ－、－Ｎ（ＣＨ_３）－、－ＣＯＮＨ－、－ＮＨＣＯ－、－ＣＨ_２Ｏ－、－ＯＣＨ_２－、－ＣＯＯ－、－ＯＣＯ－、－ＣＯＮ（ＣＨ_３）－又は－Ｎ（ＣＨ_３）ＣＯ－を表し、ｍ６は１～４の整数である。）

(In formula (3b-1), A ¹ represents a single bond, —CH ₂ —, —C ₂ H ₄ —, —C(CH ₃ ) ₂ —, —CF ₂ —, —C(CF ₃ ) ₂ —, —O—, —CO—, —NH—, —N(CH ₃ )—, —CONH—, —NHCO—, —CH ₂ O—, —OCH ₂ —, —COO—, —OCO—, —CON(CH ₃ )—, or —N(CH ₃ )CO—; m1 and m2 each independently represent an integer of 0 to 4, and m1+m2 represents an integer of 1 to 4; in formula (3b-2), m3 and m4 each independently represent an integer of 1 to 5; in formula (3b-3), A In formula (3b-4), A ³ and A ^{4 each} independently represent a single bond, —CH ₂ —, —C ₂ H ₄ —, —C(CH ₃ ) ₂ —, —CF ₂ —, —C(CF ₃ ) 2 —, _—O— , —CO—, —NH—, —N(CH 3 )—, —CONH—, —NHCO—, —CH ₂ O—, _{—OCH 2} —, —COO—, —OCO—, —CON(CH ₃ )— or —N(CH ₃ )CO—, and m6 is an integer from 1 to 4.

（（Ｒ３）～（Ｒ５）において、ｎは１～６の整数である。）

(In (R3) to (R5), n is an integer from 1 to 6.)

（Ｂｏｃはｔｅｒｔ－ブトキシカルボニル基を表す。）

(Boc represents a tert-butoxycarbonyl group.)

Diamine (a) preferably has at least one benzene ring. More preferred examples include diamines represented by the following formula (d1) or formula (d2).

（Ｘは、単結合、－Ｏ－、－Ｃ（ＣＨ_３）_２－、－ＮＨ－、－ＣＯ－、－（ＣＨ_２）_ｍ－、－ＳＯ_２－、－Ｏ－（ＣＨ_２）_ｍ－Ｏ－、－Ｏ－Ｃ（ＣＨ_３）_２－、－ＣＯ－（ＣＨ_２）_ｍ－、－ＮＨ－（ＣＨ_２）_ｍ－、－ＳＯ_２－（ＣＨ_２）_ｍ－、－ＣＯＮＨ－（ＣＨ_２）_ｍ－、－ＣＯＮＨ－（ＣＨ_２）_ｍ－ＮＨＣＯ－、又は－ＣＯＯ－（ＣＨ_２）_ｍ－ＯＣＯ－を表す。ｍは１～８の整数である。Ｙは、上記式（Ｓ１）～（Ｓ３）のいずれかの構造を表す。式（ｄ２）において、２個のＹは、互いに同一であっても異なっていてもよい。）。

(X represents a single bond, -O-, -C( _CH3 ) _2- , -NH-, -CO-, -( _CH2 ) _m- , -SO2-, -O-(CH2) _m -O- _{, -O-C(CH3)2-, -CO-(CH2 ) m- , -NH-} ( _CH2 ) _m- , _-SO2- ( _CH2 ) _m- , _-CONH- (CH2) _m- , -CONH-( _CH2 ) _m -NHCO-, or -COO-( _CH2 ) _m -OCO-. _m is an integer of 1 to 8. Y represents any of the structures of the above formulae (S1) to (S3). In formula (d2), the two Ys may be the same or different.)

Preferred examples of the diamine represented by the above formula (d1) include the following formulas (d1-1) to (d1-7). Preferred examples of the diamine represented by the above formula (d2) include the following formulas (d2-1) to (d2-6).

（Ｘ^ｖ１～Ｘ^ｖ４、Ｘ^ｐ１～Ｘ^ｐ８は、それぞれ独立に、－（ＣＨ_２）_ａ－（ａは１～１５の整数である）、－ＣＯＮＨ－、－ＮＨＣＯ－、－ＣＯＮ（ＣＨ_３）－、－ＮＨ－、－Ｏ－、－ＣＨ_２Ｏ－、－ＣＨ_２－ＯＣＯ－、－ＣＯＯ－、又は－ＯＣＯ－を表し、Ｘ^Ｖ５～Ｘ^Ｖ６、Ｘ^ｓ１～Ｘ^ｓ４は、それぞれ独立に、－Ｏ－、－ＣＨ_２Ｏ－、－ＣＯＯ－又は－ＯＣＯ－を表す。Ｘ^ｖ７は－Ｏ－、－ＣＨ_２Ｏ－、－ＣＨ_２－ＯＣＯ－、－ＣＯＯ－、又は－ＯＣＯ－を表す。Ｘ_ａ～Ｘ_ｆは、単結合、－Ｏ－、－ＮＨ－、－Ｏ－（ＣＨ_２）_ｍ－Ｏ－（ｍは１～８の整数である）を表し、Ｒ^ｖ１～Ｒ^ｖ４、Ｒ^１ａ～Ｒ^１ｈはそれぞれ独立に、－Ｃ_ｎＨ_２ｎ＋１（ｎは１～２０の整数）、－Ｏ－Ｃ_ｎＨ_２ｎ＋１（ｎは２～２０の整数）を表す。）

(X ^v1 to X ^v4 and X ^p1 to X ^p8 each independently represent -(CH ₂ ) _a - (a is an integer of 1 to 15), -CONH-, -NHCO-, -CON(CH ₃ )-, -NH-, -O-, -CH ₂ O-, -CH ₂ -OCO-, -COO-, or -OCO-; X ^v5 to X ^v6 and X ^s1 to X ^s4 each independently represent -O-, -CH ₂ O-, -COO-, or -OCO-; X ^v7 represents -O-, -CH ₂ O-, -CH ₂ -OCO-, -COO-, or -OCO-; _{X a} to X _f each independently represent a single bond, -O-, -NH-, -O-(CH ₂ ) _m -O- (m is an integer of 1 to 8), and R ^v1 to R ^v4 and R ^1a to R ^1h each independently represent -C _n H _2n+1 (n is an integer of 1 to 20) or -O-C _n H _2n+1 (n is an integer of 2 to 20).

The above-mentioned diamines having a radical initiation function or diamines having a photosensitizing function that exhibits a sensitizing effect upon irradiation with light may be used alone or in combination when producing polymer (A) in order to increase the response speed of liquid crystal display elements such as PSA type liquid crystal display elements and SC-PVA mode liquid crystal display elements.

Among the above, from the viewpoint of optimally obtaining the effects of the present invention, the diamine components preferably include p-phenylenediamine, 3,5-diaminobenzoic acid, 4,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2-(2,4-diaminophenoxy)ethyl methacrylate, 2,4-diamino-N,N-diallylaniline, diamines represented by the above formulas (R1) to (R5), diamines represented by the above formulas (z-1) to (z-18), diamines represented by the above formulas (Dp-1) to (Dp-9), and diamines represented by the above formulas (Ox-1) to (Ox-2).

Examples of the diamine component include aliphatic diamines such as metaxylenediamine, alicyclic diamines such as 4,4-methylenebis(cyclohexylamine), and diamines described in WO 2016/125870.

<<Tetracarboxylic acid component>>
The tetracarboxylic acid component refers to a component containing at least one selected from tetracarboxylic acids and tetracarboxylic acid derivatives. Examples of the tetracarboxylic acid derivatives include tetracarboxylic acid dihalides, tetracarboxylic acid dianhydrides, tetracarboxylic acid diester dichlorides, tetracarboxylic acid diesters, etc. The tetracarboxylic acid component may be composed of one or more types of tetracarboxylic acids and tetracarboxylic acid derivatives.
The tetracarboxylic acid component for producing the polymer (A) may be an aromatic tetracarboxylic acid dianhydride, an aliphatic tetracarboxylic acid dianhydride, an alicyclic tetracarboxylic acid dianhydride, or a derivative thereof. Here, the aromatic tetracarboxylic acid dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to an aromatic ring. The aliphatic tetracarboxylic acid dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups bonded to a chain hydrocarbon structure. However, it is not necessary to be composed of only a chain hydrocarbon structure, and it may have an alicyclic structure or an aromatic ring structure in part. The alicyclic tetracarboxylic acid dianhydride is an acid dianhydride obtained by intramolecular dehydration of four carboxyl groups, including at least one carboxyl group bonded to an alicyclic structure. However, none of these four carboxyl groups are bonded to an aromatic ring. In addition, it is not necessary to be composed of only an alicyclic structure, and it may have a chain hydrocarbon structure or an aromatic ring structure in part.

The tetracarboxylic acid component preferably contains a tetracarboxylic acid dianhydride represented by the following formula (S4):

（Ｘは、下記（ｘ－１）～（ｘ－１３）からなる群から選ばれる構造を表す。）

(X represents a structure selected from the group consisting of the following (x-1) to (x-13).)

（Ｒ^１～Ｒ^４は、それぞれ独立して、水素原子、メチル基、エチル基、プロピル基、塩素原子、フッ素原子を含有する炭素数１～６の１価の有機基、又はフェニル基を表す。Ｒ^５及びＲ^６は、それぞれ独立して、水素原子又はメチル基を表す。ｊ及びｋは、０又は１の整数であり、Ａ_１及びＡ_２は、それぞれ独立して、単結合、－Ｏ－、－ＣＯ－、－ＣＯＯ－、フェニレン、スルホニル、又はアミド結合を表す。＊１は一方の酸無水物基に結合する結合手であり、＊２は他方の酸無水物基に結合する結合手である。）

(R ¹ to R ⁴ each independently represent a hydrogen atom, a methyl group, an ethyl group, a propyl group, a chlorine atom, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group. R ⁵ and R ⁶ each independently represent a hydrogen atom or a methyl group. j and k are integers of 0 or 1. A ₁ and A ₂ each independently represent a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl, or an amide bond. *1 represents a bond bonded to one acid anhydride group, and *2 represents a bond bonded to the other acid anhydride group.)

More preferred examples of the above formula (x-1) include the following formulae (X1-1) to (X1-6). In the formulae, * represents a bond.

Preferred specific examples of the above (x-12) and (x-13) include the following formulae (x-14) to (x-29). In the formulae, "*" represents a bond.

Preferred examples of the tetracarboxylic dianhydride or derivative thereof represented by the above formula (S4) include tetracarboxylic dianhydrides or derivatives thereof represented by formula (3) in which X is any of the above formulae (x-1) to (x-7) and (x-11) to (x-13).

<Method for producing polymer (A)>
The polymer (A) used in the present invention can be synthesized by a known method such as that described in International Publication WO2013/157586.

Polyimide can be obtained by ring-closing (imidization) the polyimide precursor obtained in polymer (A). Note that the imidization rate 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 its derivatives).

The molecular weight of the polymer (A) used in the present invention is preferably 5,000 to 1,000,000, more preferably 10,000 to 150,000, in terms of weight average molecular weight measured by GPC (Gel Permeation Chromatography), taking into consideration the strength of the liquid crystal alignment film obtained therefrom, the workability during film formation, and the coating properties.

<Polymer (B)>
The liquid crystal aligning agent of the present invention contains a polymer (B) which includes a repeating unit structure represented by the following formula (1), has at least one triazine ring terminal, and is characterized in that at least a part of the triazine ring terminal is blocked with an arylamino group having a crosslinking group. The polymer constituting the component (B) may be composed of one type of polymer or two or more types of polymers.

（ＲおよびＲ’は、互いに独立して、水素原子、アルキル基、アルコキシ基、アリール基、またはアラルキル基を表し、
Ａｒは、式（２）～（１２）で示される群から選ばれる少なくとも１種を表す。

(R and R′ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or an aralkyl group;
Ar represents at least one selected from the group represented by formulas (2) to (12).

（式（２）～（１２）の芳香環上の任意の水素原子は置換されてもよく、
Ｒ^１２は、水素原子または炭素数１～１０のアルキル基を表し、
Ｗ¹およびＷ²は、互いに独立して、単結合、－ＣＲ⁹⁵Ｒ⁹⁶－（Ｒ⁹⁵およびＲ⁹⁶は、互いに独立して、水素原子または炭素数１～１０のアルキル基（ただし、これらは一緒になって環を形成していてもよい。）を表す。）、－Ｃ（＝Ｏ）－、－Ｏ－、－Ｓ－、－Ｓ（＝Ｏ）－、－ＳＯ₂－、または－ＮＲ⁹⁷－（Ｒ⁹⁷は、水素原子、炭素数１～１０のアルキル基又はフェニル基を表す。）を表し、
Ｘ¹およびＸ²は、互いに独立して、単結合、炭素数１～１０のアルキレン基、または－Ｙ_１－Ｐｈ－Ｙ_２－（Ｐｈはフェニレン基を表し、フェニレン基上の任意の水素原子は置換されてもよく、Ｙ₁およびＹ₂は、互いに独立して、単結合または炭素数１～１０のアルキレン基を表す。）で示される基を表す。）

(Any hydrogen atom on the aromatic ring of formulas (2) to (12) may be substituted,
R ¹² represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms;
W ¹ and W ² each independently represent a single bond, -CR ⁹⁵ R ⁹⁶ - (R ⁹⁵ and R ⁹⁶ each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms (which may be joined together to form a ring)), -C(=O)-, -O-, -S-, -S(=O)-, -SO ₂ -, or -NR ⁹⁷ - (R ⁹⁷ represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a phenyl group);
^X1 and ^X2 each independently represent a single bond, an alkylene group having 1 to 10 carbon atoms, or a group represented by _-Y1 -Ph- _Y2- (Ph represents a phenylene group, any hydrogen atom on the phenylene group may be substituted, and _Y1 and _Y2 each independently represent a single bond or an alkylene group having 1 to 10 carbon atoms).

In the above formula (1), R and R' each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or an aralkyl group. From the viewpoint of further increasing the refractive index, it is preferable that both are hydrogen atoms.
In the present invention, the number of carbon atoms in the alkyl groups R and R' in the above formula (1) is not particularly limited, but is preferably 1 to 20, and in consideration of further improving the heat resistance of the polymer, the carbon number is more preferably 1 to 10, and even more preferably 1 to 3. In addition, the structure may be any of linear, branched, and cyclic.

Specific examples of the alkyl groups R and R' in the above formula (1) include methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, 1-methyl-cyclopropyl, 2-methyl-cyclopropyl, n-pentyl, 1-methyl-n-butyl, 2-methyl-n-butyl, 3-methyl-n-butyl, 1,1-dimethyl-n-propyl, 1,2-dimethyl-n-propyl, 2,2-dimethyl-n-propyl, 1-ethyl-n-propyl, cyclopentyl, 1-methyl-cyclobutyl, 2-methyl-cyclobutyl, 3-methyl-cyclobutyl, 1,2-dimethyl-cyclopropyl, 2,3-dimethyl-cyclopropyl, 1-ethyl-cyclopropyl, 2-ethyl-cyclopropyl, n-hexyl, 1-methyl-n-pentyl, 2-methyl-n-pentyl, 3-methyl-n-pentyl, 4-methyl-n-pentyl, 1,1-dimethyl-n-butyl, 1,2-dimethyl-n-butyl, 1,3-dimethyl-n-butyl, 2,2-dimethyl-n-butyl, 2,3-dimethyl-n-butyl, 3,3-dimethyl-n-butyl, 1-ethyl-n-butyl ethyl, 2-ethyl-n-butyl, 1,1,2-trimethyl-n-propyl, 1,2,2-trimethyl-n-propyl, 1-ethyl-1-methyl-n-propyl, 1-ethyl-2-methyl-n-propyl, cyclohexyl, 1-methyl-cyclopentyl, 2-methyl-cyclopentyl, 3-methyl-cyclopentyl, 1-ethyl-cyclobutyl, 2-ethyl-cyclobutyl, 3-ethyl-cyclobutyl, 1,2-dimethyl-cyclobutyl, 1,3-dimethyl-cyclobutyl, 2,2-dimethyl-cyclobutyl, 2,3-dimethyl-cyclobutyl, 2, Examples of such cyclopropyl groups include 4-dimethyl-cyclobutyl, 3,3-dimethyl-cyclobutyl, 1-n-propyl-cyclopropyl, 2-n-propyl-cyclopropyl, 1-isopropyl-cyclopropyl, 2-isopropyl-cyclopropyl, 1,2,2-trimethyl-cyclopropyl, 1,2,3-trimethyl-cyclopropyl, 2,2,3-trimethyl-cyclopropyl, 1-ethyl-2-methyl-cyclopropyl, 2-ethyl-1-methyl-cyclopropyl, 2-ethyl-2-methyl-cyclopropyl, and 2-ethyl-3-methyl-cyclopropyl groups.

The number of carbon atoms in the alkoxy groups R and R' in the above formula (1) is not particularly limited, but is preferably 1 to 20. In consideration of further improving the heat resistance of the polymer, the number of carbon atoms is more preferably 1 to 10, and even more preferably 1 to 3. The structure of the alkyl portion may be linear, branched, or cyclic.

Specific examples of the alkoxy groups R and R' in the above formula (1) include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, 1-methyl-n-butoxy, 2-methyl-n-butoxy, 3-methyl-n-butoxy, 1,1-dimethyl-n-propoxy, 1,2-dimethyl-n-propoxy, 2,2-dimethyl-n-propoxy, 1-ethyl-n-propoxy, n-hexyloxy, 1-methyl-n-pentyloxy, 2-methyl-n-pentyloxy, Examples of the alkyl group include 3-methyl-n-pentyloxy, 4-methyl-n-pentyloxy, 1,1-dimethyl-n-butoxy, 1,2-dimethyl-n-butoxy, 1,3-dimethyl-n-butoxy, 2,2-dimethyl-n-butoxy, 2,3-dimethyl-n-butoxy, 3,3-dimethyl-n-butoxy, 1-ethyl-n-butoxy, 2-ethyl-n-butoxy, 1,1,2-trimethyl-n-propoxy, 1,2,2-trimethyl-n-propoxy, 1-ethyl-1-methyl-n-propoxy, and 1-ethyl-2-methyl-n-propoxy groups.

The number of carbon atoms in the aryl group of R and R′ in the above formula (1) is not particularly limited, but is preferably 6 to 40. In consideration of further improving the heat resistance of the polymer, the number of carbon atoms is more preferably 6 to 16, and even more preferably 6 to 13.
Specific examples of the aryl group for R and R′ in the above formula (1) include phenyl, o-chlorophenyl, m-chlorophenyl, p-chlorophenyl, o-fluorophenyl, p-fluorophenyl, o-methoxyphenyl, p-methoxyphenyl, p-nitrophenyl, p-cyanophenyl, α-naphthyl, β-naphthyl, o-biphenylyl, m-biphenylyl, p-biphenylyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl, and 9-phenanthryl groups.

The number of carbon atoms in the aralkyl group of R and R' in the above formula (1) is not particularly limited, but it is preferably 7 to 20 carbon atoms, and the alkyl portion may be linear, branched, or cyclic.
Specific examples thereof include benzyl, p-methylphenylmethyl, m-methylphenylmethyl, o-ethylphenylmethyl, m-ethylphenylmethyl, p-ethylphenylmethyl, 2-propylphenylmethyl, 4-isopropylphenylmethyl, 4-isobutylphenylmethyl, and α-naphthylmethyl groups.

Any hydrogen atom on the aromatic ring in the above formulas (2) to (12) may be substituted with a halogen atom, a carboxy group, a sulfo group, an alkyl group having 1 to 10 carbon atoms which may have a branched structure, a halogenated alkyl group having 1 to 10 carbon atoms which may have a branched structure, or an alkoxy group having 1 to 10 carbon atoms which may have a branched structure.

Examples of the halogen atom which is a substituent on the aromatic ring in the above formulas (2) to (12) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
In addition, examples of the alkyl group and alkoxy group which are the substituents on the aromatic ring in the above formulas (2) to (12) include those having the same structures as those exemplified in the above formula (1).

The halogenated alkyl group having 1 to 10 carbon atoms, which is a substituent on the aromatic ring in the above formulas (2) to (12), is an alkyl group having 1 to 10 carbon atoms, which may have a branched structure, in which at least one hydrogen atom has been substituted with a halogen atom. Specific examples of such an alkyl group include trifluoromethyl, 2,2,2-trifluoroethyl, perfluoroethyl, 3,3,3-trifluoropropyl, 2,2,3,3,3-pentafluoropropyl, 2,2,3,3-tetrafluoropropyl, 2,2,2-trifluoro-1-(trifluoromethyl)ethyl, perfluoropropyl, 4, Examples include 4,4-trifluorobutyl, 3,3,4,4,4-pentafluorobutyl, 2,2,3,3,4,4,4-heptafluorobutyl, perfluorobutyl, 2,2,3,3,4,4,5,5,5-nonafluoropentyl, 2,2,3,3,4,4,5,5-octafluoropentyl, perfluoropentyl, 2,2,3,3,4,4,5,5,6,6,6-undecafluorohexyl, 2,2,3,3,4,4,5,5,6,6-decafluorohexyl, 3,3,4,4,5,5,6,6,6-nonafluorohexyl, and perfluorohexyl groups.

Examples of the alkylene group having 1 to 10 carbon atoms for X ¹ and X ² in the above formula (11) include methylene, ethylene, propylene, trimethylene, tetramethylene, and pentamethylene groups.

Any hydrogen atom on the phenylene group in the above group "-Y ₁ -Ph-Y ₂ -" may be replaced with a halogen atom, a carboxyl group, a sulfo group, an alkyl group having 1 to 10 carbon atoms which may have a branched structure, a halogenated alkyl group having 1 to 10 carbon atoms which may have a branched structure, or an alkoxy group having 1 to 10 carbon atoms which may have a branched structure.

When any hydrogen atom on the aromatic ring in the above formulas (2) to (12) and any hydrogen atom on the phenylene group in the group "-Y ₁ -Ph-Y ₂ -" is substituted, among the above examples, a halogen atom, a sulfo group, an alkyl group having 1 to 5 carbon atoms which may have a branched structure, a halogenated alkyl group having 1 to 5 carbon atoms which may have a branched structure, or an alkoxy group having 1 to 5 carbon atoms which may have a branched structure is preferred.

As Ar in the above formula (1), at least one of the types represented by formulas (2), (5) to (12) is preferable, and at least one of the types represented by formulas (2), (5), (7), (8), (11) to (12) is more preferable. Specific examples of the aryl groups represented by the above formulas (2) to (12) include, but are not limited to, those represented by the following formulas (1-1) to (1-25). In the formulas, Ph represents a phenyl group.

Among these, the aryl groups represented by the above formulas (1-1), (1-2), (1-5) to (1-15), (1-18) to (1-21), and (1-23) to (1-25) are more preferred since they result in polymers with higher refractive indexes.

In particular, in order to further increase the solubility of the polymer in organic solvents, it is preferable that Ar is an m-phenylene group represented by formula (21-a).

Furthermore, the polymer (B) of the present invention has at least one triazine ring terminal, and at least a portion of the triazine ring terminal is blocked with an arylamino group having a crosslinking group.
The polymer (B) of the present invention has at least one triazine ring terminal, and this terminal triazine ring usually has two halogen atoms that can be substituted with the arylamino group having the crosslinking group. Therefore, the arylamino group having the crosslinking group may be bonded to the same triazine ring terminal, or when there are multiple triazine ring terminals, each of them may be bonded to a different triazine ring terminal.

Examples of the aryl group of the arylamino group having the above-mentioned bridging group include the same as those described above, but a phenyl group is particularly preferred.

Examples of crosslinking groups include hydroxy-containing groups, vinyl-containing groups, epoxy-containing groups, oxetane-containing groups, carboxy-containing groups, sulfo-containing groups, thiol-containing groups, and (meth)acryloyl-containing groups. Considering the need to improve the heat resistance of polymer (B), hydroxy-containing groups and (meth)acryloyl-containing groups are preferred.

Examples of the hydroxy-containing group include a hydroxy group, a hydroxyalkyl group, etc. Both the hydroxy group and the hydroxyalkyl group are preferred, with a hydroxyalkyl group having 1 to 10 carbon atoms being more preferred.
Examples of the hydroxyalkyl group having 1 to 10 carbon atoms include hydroxymethyl, 2-hydroxyethyl, 3-hydroxypropyl, 4-hydroxybutyl, 5-hydroxypentyl, 6-hydroxyhexyl, 7-hydroxyheptyl, 8-hydroxyoctyl, 9-hydroxynonyl, 10-hydroxydecyl, 2-hydroxy-1-methylethyl, 2-hydroxy-1,1-dimethylethyl, 3-hydroxy-1-methylpropyl, 3-hydroxy-2-methylpropyl, 3-hydroxy-1,1-dimethylpropyl, 3-hydroxy-1,2-dimethylpropyl, 3-hydroxy-2,2-dimethylpropyl, 4-hydroxyalkyl, 5-hydroxypropyl, 6-hydroxypropyl, 7-hydroxypropyl, 8-hydroxypropyl, 9-hydroxypropyl, 10-hydroxypropyl, 1 ... those in which the carbon atom to which a hydroxy group is bonded is a primary carbon atom, such as 1-hydroxyethyl, 1-hydroxypropyl, 2-hydroxypropyl, 1-hydroxybutyl, 2-hydroxybutyl, 1-hydroxyhexyl, 2-hydroxyhexyl, 1-hydroxyoctyl, 2-hydroxyoctyl, 1-hydroxydecyl, 2-hydroxydecyl, 1-hydroxy-1-methylethyl, and 2-hydroxy-2-methylpropyl groups;

In particular, in order to improve heat resistance and resistance to high temperatures and high humidity, it is preferable that the carbon atom to which the hydroxyl group is bonded is a primary carbon atom, and among these, hydroxyalkyl groups having 1 to 5 carbon atoms are more preferable, hydroxyalkyl groups having 1 to 3 carbon atoms are even more preferable, hydroxymethyl groups and 2-hydroxyethyl groups are even more preferable, and 2-hydroxyethyl groups are most preferable.

Examples of the (meth)acryloyl-containing group include a (meth)acryloyl group, a (meth)acryloyloxyalkyl group, and a group represented by the following formula (i), but a (meth)acryloyloxyalkyl group having an alkyl group having 1 to 10 carbon atoms and a group represented by the following formula (i) are preferred, and a group represented by the following formula (i) is more preferred.

(In the formula, A ¹ represents an alkylene group having 1 to 10 carbon atoms, A ² represents a single bond or a group represented by the following formula (j), A ³ represents a divalent or trivalent aliphatic hydrocarbon group which may be substituted with a hydroxy group, A ⁴ represents a hydrogen atom or a methyl group, a represents 1 or 2, and * represents a bond.)

（＊は結合手を表す。）

(* represents a bond.)

Examples of the alkyl group contained in the (meth)acryloyloxyalkyl group having an alkyl group having 1 to 10 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl groups. Considering the improvement of heat resistance and resistance to high temperature and high humidity, among these, those having an alkyl group having 1 to 5 carbon atoms are preferred, those having an alkyl group having 1 to 3 carbon atoms are preferred, and those having an alkyl group having 1 or 2 carbon atoms are more preferred.

Specific examples of the above (meth)acryloyloxyalkyl group include, for example, a (meth)acryloyloxymethyl group, a 2-(meth)acryloyloxyethyl group, a 3-(meth)acryloyloxypropyl group, and a 4-(meth)acryloyloxybutyl group.

In formula (i), A ¹ is an alkylene group having 1 to 10 carbon atoms, preferably an alkylene group having 1 to 5 carbon atoms, more preferably a methylene group or an ethylene group. Examples of the alkylene group having 1 to 10 carbon atoms include methylene, ethylene, propylene, trimethylene, tetramethylene, and pentamethylene groups.

^A2 represents a single bond or a group represented by formula (j), preferably a group represented by formula (j).

^A3 is a divalent or trivalent aliphatic hydrocarbon group which may be substituted with a hydroxy group, specific examples of which include an alkylene group having 1 to 5 carbon atoms and groups represented by the following formulas (k-1) to (k-3), with an alkylene group having 1 to 5 carbon atoms being preferred, an alkylene group having 1 to 3 carbon atoms being more preferred, and a methylene group and an ethylene group being even more preferred. Examples of the alkylene group for ^A3 include the alkylene groups having 1 to 5 carbon atoms listed as examples of ^A1 .

（式中、＊は、上記と同様である。）

(In the formula, * is the same as above.)

In formula (i), a represents 1 or 2, with 1 being preferred.

A preferred embodiment of the group represented by formula (i) is represented by the following formula (i-1):

（式中、Ａ¹、Ａ³、Ａ⁴および＊は、上記と同様である。）

(In the formula, A ¹ , A ³ , A ⁴ and * are the same as above.)

More preferred embodiments of the group represented by formula (i) include those represented by the following formulas (i-2) to (i-3).

(In the formula, * is the same as above.)

Examples of vinyl-containing groups include alkenyl groups having 2 to 10 carbon atoms and a vinyl group at the end. Specific examples include ethenyl, 1-propenyl, allyl, isopropenyl, 1-butenyl, 2-butenyl, and 2-pentenyl groups.

Epoxy-containing groups include epoxy groups, glycidyl groups, glycidylalkyl groups, glycidyloxy groups, etc. Specific examples include glycidylmethyl, 2-glycidylethyl, 3-glycidylpropyl, and 4-glycidylbutyl groups.

Examples of oxetane-containing groups include oxetan-3-yl, (oxetan-3-yl)methyl, 2-(oxetan-3-yl)ethyl, 3-(oxetan-3-yl)propyl, and 4-(oxetan-3-yl)butyl groups.

Examples of the carboxy-containing group include a carboxy group and a carboxyalkyl group having 1 to 10 carbon atoms. As the carboxyalkyl group having 1 to 10 carbon atoms, the carbon atom to which the carboxy group is bonded is preferably a primary carbon atom, and specific examples include a carboxymethyl group, a 2-carboxyethyl group, a 3-carboxypropyl group, and a 4-carboxybutyl group.

Examples of sulfo-containing groups include sulfo groups and sulfoalkyl groups having 1 to 10 carbon atoms. As sulfoalkyl groups having 1 to 10 carbon atoms, the carbon atom to which the sulfo group is bonded is preferably a primary carbon atom, and specific examples include sulfomethyl, 2-sulfoethyl, 3-sulfopropyl, and 4-sulfobutyl groups.

Examples of thiol-containing groups include thiol groups and mercaptoalkyl groups having 1 to 10 carbon atoms. As the mercaptoalkyl group having 1 to 10 carbon atoms, it is preferable that the carbon atom to which the thiol group is bonded is a primary carbon atom, and specific examples include mercaptomethyl, 2-mercaptoethyl, 3-mercaptopropyl, and 4-mercaptobutyl groups.

The number of bridging groups is not particularly limited and can be any number that can be substituted on the aryl group, but 1 to 4 is preferred, 1 to 2 is more preferred, and 1 is even more preferred.

Suitable arylamino groups having a bridging group include those represented by formula (15), and in particular, those represented by formula (16) having a bridging group in the para position relative to the amino group are preferred.

（式中、Ｒ^1５は、架橋基を表す。＊は結合手を表す。）

(In the formula, ^R15 represents a bridging group. * represents a bond.)

（式中、Ｒ^1５は、上記と同じ意味を表す。＊は結合手を表す。）

(In the formula, ^R15 has the same meaning as above. * represents a bond.)

Specific examples of arylamino groups having a bridging group include, but are not limited to, those shown in the following formulas (16-1) to (16-13). In the formulas, * represents a bond.

An arylamino group having a hydroxyalkyl group can be introduced by using a corresponding hydroxyalkyl group-substituted arylamino compound in the production method described below.
Specific examples of the hydroxyalkyl group-substituted arylamino compound include (4-aminophenyl)methanol and 2-(4-aminophenyl)ethanol.

An arylamino group having a (meth)acryloyloxyalkyl group can be introduced by using a corresponding (meth)acryloyloxyalkyl group-substituted arylamino compound, or by introducing an arylamino group having a hydroxyalkyl group into polymer (B) and then reacting the hydroxy group contained in the hydroxyalkyl group with a (meth)acrylic acid halide or glycidyl (meth)acrylate.

An arylamino group having a group represented by formula (i) can be introduced by a method using an arylamino compound having the desired crosslinking group, or by a method in which an arylamino group having a hydroxyalkyl group is introduced into polymer (B) and then a (meth)acrylic acid ester compound having an isocyanate group represented by the following formula (i') is allowed to react with the hydroxy group contained in the hydroxyalkyl group.

(In the formula, ^A3 , ^A4 and a are the same as above.)

Specific examples of the (meth)acryloyloxyalkyl group-substituted arylamino compound include ester compounds obtained by reacting a hydroxy group of the above-mentioned hydroxyalkyl group-substituted arylamino compound with a (meth)acrylic acid halide or glycidyl (meth)acrylate.
The (meth)acrylic acid halide may include (meth)acrylic acid chloride, (meth)acrylic acid bromide, and (meth)acrylic acid iodide.
Specific examples of the (meth)acrylic acid ester compound having an isocyanate group represented by the above formula (i') include 2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate, and 1,1-(bisacryloyloxymethyl)ethyl isocyanate.

In the present invention, particularly suitable polymers (B) include those containing repeating units represented by formulas (18) to (21).

（式中、Ｒ、Ｒ’、およびＲ^１５は、上記と同じ意味を表す。Ｒ^１～Ｒ^４は、水素原子、ハロゲン原子、カルボキシ基、スルホ基、炭素数１～１０の分岐構造を有していてもよいアルキル基、炭素数１～１０の分岐構造を有していてもよいハロゲン化アルキル基、または炭素数１～１０の分岐構造を有していてもよいアルコキシ基を表す。ただし、Ｒ、Ｒ’が同時に水素原子である場合を除く。）

(In the formula, R, R', and ^R15 have the same meaning as above. ^R1 to ^R4 each represent a hydrogen atom, a halogen atom, a carboxy group, a sulfo group, an alkyl group having 1 to 10 carbon atoms which may have a branched structure, a halogenated alkyl group having 1 to 10 carbon atoms which may have a branched structure, or an alkoxy group having 1 to 10 carbon atoms which may have a branched structure, except when R and R' are both hydrogen atoms.)

(In the formula, R ¹⁵ has the same meaning as above. ^{R 1} to R ⁴ have the same meaning as in formula (18) above, except that all of R ¹ to R ⁴ are hydrogen atoms.)

(In the formula, R ¹⁵ has the same meaning as above.)

(In the formula, R ¹⁵ has the same meaning as above.)

The weight average molecular weight of the polymer (B) in the present invention is not particularly limited, but is preferably 500 to 500,000, more preferably 500 to 100,000. From the viewpoint of further improving heat resistance and reducing the shrinkage rate, it is preferably 2,000 or more. From the viewpoint of further increasing solubility and reducing the viscosity of the obtained solution, it is preferably 50,000 or less, more preferably 30,000 or less, even more preferably 15,000 or less, and particularly preferably 10,000 or less.
The weight average molecular weight in the present invention is an average molecular weight obtained by gel permeation chromatography (hereinafter referred to as GPC) analysis in terms of standard polystyrene.

The polymer (B) (hyperbranched polymer) of the present invention can be produced in accordance with the method disclosed in the above-mentioned WO 2010/128661.
That is, a trihalogenated triazine compound is reacted with an aryldiamino compound in an organic solvent, and then the resulting mixture is reacted with at least one arylamino compound selected from an arylamino compound having a hydroxyalkyl group (hydroxy-containing group), an arylamino compound having an acryloyloxyalkyl group (acryloyl-containing group), and an arylamino compound having a group represented by formula (i) (acryloyl-containing group), thereby obtaining the polymer (B) of the present invention.

For example, as shown in Scheme 1 below, polymer (B) (20') can be obtained by reacting a triazine compound (22) with an aryldiamino compound (23) in a suitable organic solvent, followed by reaction with at least one arylamino compound (24), which is an end-capping agent, selected from arylamino compounds having a hydroxyalkyl group and arylamino compounds having a group represented by formula (i).

（式中、Ｘは、互いに独立してハロゲン原子を表し、Ｒ^aは、ヒドロキシアルキル基または式（ｉ）で表される基を表す。）

(In the formula, X's each independently represent a halogen atom, and R ^a represents a hydroxyalkyl group or a group represented by formula (i).

In the above reaction, the charging ratio of the aryldiamino compound (23) is arbitrary as long as the target polymer is obtained, but the charging ratio is preferably 0.01 to 10 equivalents, more preferably 1 to 5 equivalents, of the aryldiamino compound (23) relative to 1 equivalent of the triazine compound (22).
The aryldiamino compound (23) may be added neat or in the form of a solution dissolved in an organic solvent. In consideration of ease of operation and control of the reaction, the latter method is preferred.
The reaction temperature may be appropriately set within the range from the melting point to the boiling point of the solvent used, and is preferably from about -30 to 150°C, more preferably from -10 to 100°C.

Another embodiment is the method shown in the following scheme 2. In this method, the polymer (B) (20') can be obtained by reacting a triazine compound (22) with an aryldiamino compound (23) in a suitable organic solvent, and then reacting the resulting mixture with an arylamino compound (24') having a hydroxyalkyl group, which is an end-capping agent, to obtain a polymer (B) (20'') (first step), and then reacting a (meth)acrylic acid ester compound having an isocyanate group represented by formula (i') with the hydroxy group of the hydroxyalkyl group contained in the polymer (B) (20'') (second step).
When the polymer (B) (20'') is the target product, the reaction may be completed in the first stage without carrying out the second stage reaction.

（式中、Ｒ^a1は、ヒドロキシアルキル基を表し、Ｘ、Ａ³、Ａ⁴、Ｒ^aおよびａは、上記と同じ意味を表す。）

(In the formula, R ^a1 represents a hydroxyalkyl group, and X, A ³ , A ⁴ , R ^a and a each have the same meaning as above.)

In the above reaction, the charge ratio and addition method of the aryldiamino compound (23) in the first step, and the reaction temperature in the reaction until the polymer (B) (20″) is obtained can be the same as those explained in Scheme 1.
In the second step, the charge ratio of the (meth)acrylic acid ester compound having an isocyanate group represented by formula (i') to the polymer (B) (20'') can be arbitrarily set depending on the ratio of the hydroxyalkyl group to the group represented by formula (i), and is preferably 0.1 to 10 equivalents, more preferably 0.5 to 5 equivalents, even more preferably 0.7 to 3 equivalents, and even more preferably 0.9 to 1.5 equivalents relative to 1 equivalent of the arylamino compound having a hydroxyalkyl group used. For example, when all of the hydroxyalkyl groups contained in the polymer (B) (20'') are groups represented by formula (i), the charge ratio is preferably 1.0 to 10 equivalents, more preferably 1.0 to 5 equivalents, even more preferably 1.0 to 3 equivalents, and even more preferably 1.0 to 1.5 equivalents of the (meth)acrylic acid ester compound relative to 1 equivalent of the arylamino compound having a hydroxyalkyl group used.
The reaction temperature in this reaction is similar to the reaction temperature in the reaction to obtain the polymer (B) (20''); however, in consideration of preventing polymerization of the (meth)acryloyl group during the reaction, the reaction temperature is preferably 30 to 80°C, more preferably 40 to 70°C, and even more preferably 50 to 60°C.

As the organic solvent, various solvents usually used in this type of reaction can be used, and examples thereof include amide solvents such as tetrahydrofuran (THF), 1,4-dioxane, dimethyl sulfoxide, N,N-dimethylformamide, N-methyl-2-pyrrolidone, tetramethylurea, hexamethylphosphoramide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N,N-dimethylethyleneurea, N,N,N',N'-tetramethylmalonamide, N-methyl-ε-caprolactam, N-acetylpyrrolidine, N,N-diethylacetamide, N-ethyl-2-pyrrolidone, N,N-dimethylpropionic acid amide, N,N-dimethylisobutyramide, N-methylformamide, and N,N'-dimethylpropyleneurea, and mixed solvents thereof.
Among these, N,N-dimethylformamide, dimethylsulfoxide, N-methyl-2-pyrrolidone, N,N-dimethylacetamide, and mixtures thereof are preferred, with N,N-dimethylacetamide and N-methyl-2-pyrrolidone being particularly preferred.

In the first step of the reaction in Scheme 1, various bases that are commonly used may be added during or after the polymerization.
Specific examples of the base include potassium carbonate, potassium hydroxide, sodium carbonate, sodium hydroxide, sodium hydrogencarbonate, sodium ethoxide, sodium acetate, lithium carbonate, lithium hydroxide, lithium oxide, potassium acetate, magnesium oxide, calcium oxide, barium hydroxide, trilithium phosphate, trisodium phosphate, tripotassium phosphate, cesium fluoride, aluminum oxide, ammonia, n-propylamine, trimethylamine, triethylamine, diisopropylamine, diisopropylethylamine, N-methylpiperidine, 2,2,6,6-tetramethyl-N-methylpiperidine, pyridine, 4-dimethylaminopyridine, N-methylmorpholine, and the like.
The amount of the base to be added is preferably 1 to 100 equivalents relative to 1 equivalent of the triazine compound (22), and more preferably 1 to 10 equivalents. The base may be used in the form of an aqueous solution.
It is preferred that no raw material components remain in the resulting polymer, but some raw materials may remain as long as the effects of the present invention are not impaired.
After completion of the reaction, the product can be easily purified by a method such as reprecipitation.

As a method for blocking the terminals using an arylamino compound having a crosslinking group, a known method may be adopted.
In this case, the amount of the end-capping agent used is preferably about 0.05 to 10 equivalents, more preferably 0.1 to 5 equivalents, and even more preferably 0.5 to 2 equivalents, per equivalent of halogen atoms derived from the excess triazine compound not used in the polymerization reaction.
The reaction solvent and reaction temperature may be the same as those described in the first step of the above scheme 1, and the end-capping agent may be charged simultaneously with the aryldiamino compound (23).
In addition, an unsubstituted arylamino compound having no crosslinking group may be used, and the terminals may be blocked with two or more groups. The aryl groups of this unsubstituted arylamino compound may be the same as those mentioned above.

Specific examples of unsubstituted arylamino groups include, but are not limited to, those shown in formula (26) below.

The unsubstituted arylamino group can be introduced by using a corresponding unsubstituted arylamino compound in the production method described below.
Specific examples of unsubstituted arylamino compounds include aniline.

In addition, when an unsubstituted arylamino group is introduced, the ratio of the arylamino compound having a crosslinking group to the unsubstituted arylamino compound is preferably 0.1 to 1.0 mol, more preferably 0.1 to 0.5 mol, and even more preferably 0.1 to 0.3 mol of the unsubstituted arylamino compound per 1 mol of the arylamino compound having a crosslinking group, from the viewpoint of achieving a good balance between solubility in organic solvents and resistance to yellowing.

(Liquid crystal alignment agent)
The liquid crystal aligning agent is used to prepare a liquid crystal alignment film, and takes the form of a coating liquid from the viewpoint of forming a uniform thin film. The liquid crystal aligning agent of the present invention is also preferably a coating liquid containing the above-mentioned polymer component and an organic solvent. In this case, the concentration of the polymer component in the liquid crystal aligning agent can be appropriately changed depending on the setting of the thickness of the coating film to be formed. From the viewpoint of forming a uniform and defect-free coating film, 0.5% by mass or more is preferable, and from the viewpoint of storage stability of the solution, 15% by mass or less is preferable. A particularly preferable concentration of the polymer component is 1 to 10% by mass.

From the viewpoint of enhancing the liquid crystal alignment property, the content ratio of the (A) component and the (B) component contained in the liquid crystal alignment agent of the present invention may be 10/90 to 90/10 in terms of the mass ratio of [(A) component]/[(B) component], or may be 20/80 to 90/10, or may be 20/80 to 80/20.

In addition, the liquid crystal alignment agent used in the production of the liquid crystal alignment film may contain polymer (A) or polymer (B) as a polymer component, or other polymers other than these may be mixed. In this case, the content of the other polymers is 0.5% by mass to 15% by mass, preferably 1% by mass to 10% by mass, of the total amount of the polymer components. Examples of other polymers include acrylic polymers, methacrylic polymers, polystyrene, polyamides, and polysiloxanes.

The solvent contained in the liquid crystal alignment agent is not particularly limited as long as it can dissolve the polymer (A) and the polymer (B), and examples thereof include lactone solvents such as γ-valerolactone and γ-butyrolactone; lactam solvents such as γ-butyrolactam, 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, N-cyclohexyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and N-methyl-2-pyrrolidone; N,N-dimethylformamide, N,N-dimethyla Amide solvents such as cetoamide, N,N-dimethyl lactamide, 3-butoxy-N,N-dimethyl propanamide, 3-methoxy-N,N-dimethyl propanamide, 3-hexyloxy-N,N-dimethyl propanamide, isopropoxy-N-isopropyl-propionamide, n-butoxy-N-isopropyl-propionamide; 4-hydroxy-4-methyl-2-pentanone, 2,6-dimethyl-4-heptanone (diisobutyl ketone), methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, isoamyl lactate, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol Cholesterol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol mono-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene glycol ethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene Examples of the glycol monomethyl ether acetate include glycol monomethyl ether acetate, propylene glycol monobutyl ether, propylene glycol diacetate, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, isoamyl propionate, isoamyl isobutyrate, diisopropyl ether, diisopentyl ether, carbonate solvents such as ethylene carbonate and propylene carbonate, 1-hexanol, cyclohexanol, 1,2-ethanediol, 2,6-dimethyl-4-heptanol (diisobutyl carbinol), propylene carbonate, etc. These can be used alone or in combination of two or more.

Preferred solvent combinations 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, and N-methyl-2-pyrrolidone, γ-butyrolactone and 4-hydroxy-4-methyl-2-pentanone. and diethylene glycol diethyl ether, N-ethyl-2-pyrrolidone, N-methyl-2-pyrrolidone, and 4-hydroxy-4-methyl-2-pentanone, N-methyl-2-pyrrolidone, 4-hydroxy-4-methyl-2-pentanone, and diisobutyl ketone, N-methyl-2-pyrrolidone, 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, 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 Examples of the solvent include 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, etc. The type and content of such a solvent are appropriately selected depending on the coating device, coating conditions, coating environment, etc. of the liquid crystal alignment agent.

<Other ingredients>
The liquid crystal aligning agent of the present invention may contain other components other than those described above, such as a crosslinkable compound, a functional silane compound, a surfactant, a compound having a photopolymerizable group, etc., if necessary.

The crosslinkable compound can be used for the purpose of increasing the strength of the liquid crystal alignment film. Examples of such crosslinkable compounds include compounds having an isocyanate group or a cyclocarbonate group, or compounds having at least one group selected from the group consisting of lower alkoxyalkyl groups, as described in paragraphs [0109] to [0113] of International Publication WO2016/047771, as well as compounds having a blocked isocyanate group.

Blocked isocyanate compounds are commercially available, and examples of suitable products that can be used include Coronate AP Stable M, Coronate 2503, 2515, 2507, 2513, 2555, Millionate MS-50 (all manufactured by Tosoh Corporation), Takenate B-830, B-815N, B-820NSU, B-842N, B-846N, B-870N, B-874N, B-882N (all manufactured by Mitsui Chemicals, Inc.), etc.

Specific examples of preferred crosslinkable compounds include compounds represented by the following formulas (CL-1) to (CL-11).

The above are examples of crosslinkable compounds, and the present invention is not limited to these. The crosslinkable compounds used in the liquid crystal aligning agent of the present invention may be one type or a combination of two or more types.

The content of other crosslinkable compounds in the liquid crystal alignment agent of the present invention is 0.1 to 150 parts by mass, or 0.1 to 100 parts by mass, or 1 to 50 parts by mass per 100 parts by mass of all polymer components.

The functional silane compound can be used for the purpose of improving the adhesion between the liquid crystal alignment film and the base substrate. Specific examples include the silane compounds described in paragraph [0019] of International Publication WO 2014/119682. The content of the functional silane compound is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, based on 100 parts by mass of all polymer components.

Surfactants can be used to improve the uniformity of the film thickness and surface smoothness of the liquid crystal alignment film. Examples of surfactants include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants. Specific examples of these surfactants include those described in paragraph [0117] of International Publication WO2016/047771. The amount of surfactant used is preferably 0.01 to 2 parts by mass, more preferably 0.01 to 1 part by mass, based on 100 parts by mass of all polymer components contained in the liquid crystal alignment agent.

Examples of compounds having a photopolymerizable group include compounds having one or more polymerizable unsaturated groups, such as an acrylate group or a methacrylate group, in the molecule, such as compounds represented by the following formulas (M-1) to (M-7).

Furthermore, the liquid crystal aligning agent of the present invention can be added with a nitrogen-containing heterocyclic amine compound represented by formula [M1] to formula [M156], more preferably 3-picolylamine and 4-picolylamine, as described in paragraphs [0194] to [0200] of International Publication WO2011/132751 (published October 27, 2011), as a compound that promotes charge transfer in the liquid crystal alignment film and promotes charge escape from the element. This amine compound may be added directly to the liquid crystal aligning agent, but it is preferable to add it after making it into a solution with a concentration of 0.1 to 10% by mass, preferably 1 to 7% by mass. There are no particular limitations on this solvent, so long as it dissolves the polymer component.

An imidization accelerator or the like may be added to the liquid crystal alignment agent of the present invention in order to efficiently promote imidization by heating when baking the coating film.

The solid content concentration in the liquid crystal alignment agent (the ratio of the total mass of the components other than the solvent of the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) is appropriately selected in consideration of viscosity, volatility, etc., and is preferably in the range of 0.5 to 15 mass%, more preferably 1 to 10 mass%.
The particularly preferred range of solid content varies depending on the method used to apply the liquid crystal alignment agent to the substrate. For example, in the case of the spin coating method, the solid content is particularly preferably in the range of 1.5 to 4.5% by mass. In the case of the printing method, the solid content is particularly preferably in the range of 3 to 9% by mass, thereby making the solution viscosity in the range of 12 to 50 mPa·s. In the case of the inkjet method, the solid content is particularly preferably in the range of 1 to 5% by mass, thereby making the solution viscosity in the range of 3 to 15 mPa·s.

(Liquid crystal alignment film/Liquid crystal display element)
The liquid crystal alignment film of the present invention is obtained from the liquid crystal alignment agent. The liquid crystal alignment film of the present invention can be used for horizontal alignment type or vertical alignment type liquid crystal alignment film, and is particularly suitable for vertical alignment type liquid crystal display elements such as VA type liquid crystal display elements or PSA type liquid crystal display elements. The liquid crystal display element of the present invention is provided with the liquid crystal alignment film. The liquid crystal display element of the present invention can be manufactured, for example, by a method including the following steps (1) to (3) or steps (1) to (4). The liquid crystal alignment film of the present invention can be preferably used for a liquid crystal display element obtained by a manufacturing method of a liquid crystal display element, which comprises applying a coating film onto a pair of substrates having a conductive film to form a coating film, arranging the coating films so as to face each other via a layer of liquid crystal molecules to form a liquid crystal cell, and irradiating the liquid crystal cell with light while applying a voltage between the conductive films of the pair of substrates. More specifically, it is a PSA type liquid crystal display element or a liquid crystal display element for SC-PVA mode, which will be described later.

(1) Step of applying liquid crystal alignment agent to substrate The liquid crystal alignment agent of the present invention is applied to one side of a substrate provided with a patterned transparent conductive film by an appropriate application method such as a roll coater method, a spin coat method, a printing method, an inkjet method, etc. Here, the substrate is not particularly limited as long as it is a highly transparent substrate, and plastic substrates such as acrylic substrates and polycarbonate substrates can be used in addition to glass substrates and silicon nitride substrates. 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 light-reflecting material such as aluminum can be used for the electrode.

(2) Step of baking the coating film After the liquid crystal alignment agent is applied, preliminary heating (pre-baking) is preferably performed first for the purpose of preventing dripping of the applied alignment agent. The pre-baking temperature is preferably 30 to 200°C, more preferably 40 to 150°C, and particularly preferably 40 to 100°C. The pre-baking time is preferably 0.25 to 10 minutes, more preferably 0.5 to 5 minutes. Then, in order to completely remove the solvent, it is preferable to perform a further heating (post-baking) step.
The post-baking temperature is preferably 80 to 300° C., more preferably 120 to 250° C. The post-baking time is preferably 5 to 200 minutes, more preferably 10 to 100 minutes. The film thus formed has a thickness of preferably 5 to 300 nm, more preferably 10 to 200 nm.

The coating film formed in the above step (1) can be used as it is as a liquid crystal alignment film, but the coating film may be subjected to an alignment ability imparting treatment. Examples of the alignment ability imparting treatment include a rubbing treatment in which the coating film is rubbed in a certain direction with a roll wrapped with a cloth made of fibers such as nylon, rayon, or cotton, and a photoalignment treatment in which the coating film is irradiated with polarized or non-polarized radiation.

In the photo-alignment treatment, the radiation irradiated to the coating film can be, for example, ultraviolet light and visible light containing light with a wavelength of 150 to 800 nm. When the radiation is polarized, it may be linearly polarized or partially polarized. Furthermore, when the radiation used is linearly polarized or partially polarized, the irradiation may be performed from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these. When irradiating with unpolarized radiation, the direction of irradiation is oblique.

(3) Step of forming a liquid crystal layer (3-1) In the case of a VA-type liquid crystal display element Two substrates on which a liquid crystal alignment film is formed as described above are prepared, and liquid crystal is placed between the two substrates arranged opposite each other. Specifically, the following two methods can be mentioned. The first method is a conventionally known method. First, the two substrates are arranged opposite each other with a gap (cell gap) between them so that the respective liquid crystal alignment films face each other. Next, the peripheries of the two substrates are bonded together using a sealant, and a liquid crystal composition is injected and filled into the substrate surfaces and the cell gap partitioned by the sealant so as to come into contact with the film surface, and then the injection hole is sealed.

The second method is a method called the ODF (One Drop Fill) method. For example, a UV-curable sealant is applied to a predetermined location on one of the two substrates on which a liquid crystal alignment film is formed, and a liquid crystal composition is dropped at several predetermined locations on the liquid crystal alignment film surface. The other substrate is then attached so that the liquid crystal alignment film faces the other substrate, and the liquid crystal composition is spread over the entire surface of the substrate and brought into contact with the film surface. Next, the entire surface of the substrate is irradiated with UV light to cure the sealant. In either method, it is desirable to remove the flow alignment that occurs during liquid crystal filling by heating the substrate to a temperature at which the liquid crystal composition used assumes an isotropic phase and then slowly cooling to room temperature.

(3-2) In the case of producing a PSA type liquid crystal display element, the same procedure as in (3-1) above is followed except that a liquid crystal composition containing a polymerizable compound is injected or dropped. Examples of the polymerizable compound include those represented by the above formulas (M-1) to (M-7).

(3-3) In the case where a coating film is formed on a substrate using a liquid crystal alignment agent containing a compound having a polymerizable group (LCD element for SC-PVA mode)
A method of manufacturing a liquid crystal display element may be adopted in which the liquid crystal display element is manufactured through a process of irradiating ultraviolet light described later after the above-mentioned (3-1). 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 polymerizable unsaturated groups in the molecule, such as an acrylate group or a methacrylate group, as represented by the above formulas (M-1) to (M-7), 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 polymer components. The polymerizable group may be possessed by a polymer used in a liquid crystal alignment agent, and an example of such a polymer includes a polymer obtained by using a diamine component containing a diamine having the above-mentioned photopolymerizable group at its terminal in a reaction.

(4) Step of irradiating 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 (3-2) or (3-3) 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 , and more preferably 1,000 to 100,000 J/m ² .

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

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

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these. The meanings of the abbreviations of the compounds used in the examples are as follows:

(Specific diamine)
DA-1 to DA-5: Compounds represented by the following formulas [DA-1] to [DA-5], respectively.

(Tetracarboxylic acid component)
D1: 1,2,3,4-cyclobutanetetracarboxylic dianhydride D2: bicyclo[3,3,0]octane-2,4,6,8-tetracarboxylic dianhydride D3: benzene-1,2,4,5-tetracarboxylic anhydride

(Additive Components)
A-1: A compound represented by the following formula [A-1]

(Triazine ring-containing polymer)
T-1: A compound having a repeating unit structure represented by the following formula [T-1] T-2: A compound having a repeating unit structure represented by the following formula [T-2]

(solvent)
NMP: N-methyl-2-pyrrolidone BCS: Ethylene glycol monobutyl ether THF: Tetrahydrofuran DMAc: N,N-dimethylacetamide

(Measurement of molecular weight of polymer (A))
The molecular weight of the polymer (A) in the synthesis examples was measured as follows using a room temperature gel permeation chromatography (GPC) apparatus (SSC-7200) manufactured by Senshu Scientific Co., Ltd. and columns (KD-803, KD-805) manufactured by Shodex Co., Ltd.
Column temperature: 50°C
Eluent: N,N-dimethylformamide (additives: lithium bromide monohydrate (LiBr.HO) 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 calibration curves: TSK standard polyethylene oxide (molecular weights: approximately 900,000, 150,000, 100,000, and 30,000) manufactured by Tosoh Corporation, and polyethylene glycol (molecular weights: approximately 12,000, 4,000, and 1,000) manufactured by Polymer Laboratory.

(Synthesis of Polymer (A))
<Synthesis Example 1>
Tetracarboxylic dianhydride D2 (15.01 g), diamine components DA-1 (15.65 g, molar ratio 0.3 relative to the total diamine components), DA-2 (8.33 g, molar ratio 0.35 relative to the total diamine components), DA-3 (5.95 g, molar ratio 0.2 relative to the total diamine components), and DA-4 (5.81 g, molar ratio 0.15 relative to the total diamine components) were mixed in NMP solvent (203.00 g) and reacted at 60 ° C. for 3 hours, and then tetracarboxylic dianhydride D1 (11.30 g) and NMP (44.24 g) were added and mixed, and reacted at 40 ° C. for 12 hours to obtain a polyamic acid solution (A). The number average molecular weight of this polyamic acid polymer was 9,600, and the weight average molecular weight was 22,900.

<Synthesis Example 2>
Tetracarboxylic dianhydride D1 (14.43 g), diamine components DA-2 (9.12 g, molar ratio 0.4 to the total diamine components), DA-3 (8.36 g, molar ratio 0.3 to the total diamine components), and DA-5 (14.16 g, molar ratio 0.3 to the total diamine components) were mixed in NMP solvent (221.94 g) and reacted at room temperature for 1 hour, and then tetracarboxylic dianhydride D3 (7.52 g) and NMP (81.79 g) were added and mixed, and reacted at room temperature for 12 hours to obtain a polyamic acid solution (B). The number average molecular weight of this polyamic acid polymer was 10,800, and the weight average molecular weight was 32,500.

(Synthesis of Polymer (B))
<Preparation of triazine ring-containing polymer solution>
<Synthesis Example 3>

In a 1,000 mL four-neck flask, 1,3-phenylenediamine [2] (42.22 g, 0.390 mol, manufactured by Amino-Chem Co., Ltd.) and DMAc (672.62 g, manufactured by Kanto Chemical Co., Ltd.) were added, and after nitrogen replacement, 1,3-phenylenediamine [2] was dissolved in DMAc by stirring. Then, it was cooled to -10 ° C. in an ethanol-dry ice bath, and 2,4,6-trichloro-1,3,5-triazine [1] (60.00 g, 0.325 mol, manufactured by Tokyo Chemical Industry Co., Ltd.) was added while making sure that the internal temperature did not exceed 0 ° C. After stirring for 30 minutes, the reaction solution was heated to 85 ± 5 ° C. by setting the oil bath to 90-100 ° C. After stirring at an internal temperature of 85°C for 1 hour, aniline [6] (18.18 g, 0.195 mol, Tokyo Chemical Industry Co., Ltd.) and 2-(4-aminophenyl)ethanol [3] (26.78 g, 0.195 mol, Oakwood Corporation) were dissolved in DMAc (42.93 g) in advance and added dropwise, followed by stirring for 3 hours. Then, 2-aminoethanol (59.62 g, Tokyo Chemical Industry Co., Ltd.) was added dropwise, the temperature was lowered to room temperature, and stirring was continued for 30 minutes, after which the stirring was stopped. THF (369 g), ammonium acetate (415 g) and ion-exchanged water (415 g) were added to the reaction solution, followed by stirring for 30 minutes. After stirring was stopped, the solution was transferred to a separatory funnel, separated into an organic layer and an aqueous layer, and the organic layer was collected. The recovered organic layer was dropped into a mixture of methanol (461 g) and ion-exchanged water (1,845 g) to cause reprecipitation. The resulting precipitate was filtered and dried at 120° C. for 8 hours using a vacuum dryer to obtain 89.3 g of the target polymer compound [10] (hereinafter referred to as T-1). The measurement result of the ¹ H-NMR spectrum of compound T-1 is shown in FIG.
The weight average molecular weight Mw of compound T-1 measured by GPC in terms of polystyrene was 23,350, and the polydispersity Mw/Mn was 6.5.
The triazine ring-containing polymer (T-1) (5.00 g) and NMP solvent (20.0 g) were dissolved by stirring at 40° C. for 12 hours to obtain a triazine ring-containing polymer solution (C).

<Synthesis Example 4>

1,3-phenylenediamine [2] (45.15 g, 0.418 mol) and DMAc (685.16 g) were added to a 1,000 mL four-neck flask, and after replacing with nitrogen, 1,3-phenylenediamine [2] was dissolved in DMAc by stirring. Then, it was cooled to -10 ° C in an ethanol-dry ice bath, and 2,4,6-trichloro-1,3,5-triazine [1] (70.00 g, 0.380 mol) was added while making sure that the internal temperature did not exceed 0 ° C. After stirring for 30 minutes, the reaction vessel was transferred to an oil bath set at 90 to 110 ° C, and the reaction solution was heated until the internal temperature reached 85 ± 5 ° C. After stirring for 1 hour, 3-aminophenol [3] (49.71 g, 0.456 mol, manufactured by Tokyo Chemical Industry Co., Ltd.) dissolved in DMAc (120.91 g) was added dropwise, and the mixture was stirred for 3 hours. Then, 2-aminoethanol (69.56 g, manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise, and the mixture was stirred for 30 minutes, after which the stirring was stopped. THF (416 g), ammonium acetate (468.2 g) and ion-exchanged water (468.2 g) were added to the reaction solution, and the mixture was stirred for 30 minutes. After the stirring was stopped, the solution was transferred to a separatory funnel, separated into an organic layer and an aqueous layer, and the organic layer was collected. The collected organic layer was added dropwise to a mixture of methanol (1,040 g) and ion-exchanged water (1,561 g) to cause reprecipitation. The resulting precipitate was filtered and dried at 120° C. for 8 hours using a vacuum dryer, yielding 95.1 g of the target polymer compound [5] (hereinafter referred to as T-2).
The weight average molecular weight Mw of compound T-2 measured by GPC in terms of polystyrene was 12,384, and the polydispersity Mw/Mn was 3.3. The measurement results of ^{the 1} H-NMR spectrum of compound T-2 are shown in FIG.
The triazine ring-containing polymer (T-2) (5.00 g) and NMP solvent (20.0 g) were dissolved by stirring at 40° C. for 12 hours to obtain a triazine ring-containing polymer solution (D).

<Preparation of Liquid Crystal Alignment Agent>
Example 1
NMP (3.88 g) and BCS (10.0 g) were added to the polyamic acid solution (A) (1.8 g) obtained in Synthesis Example 1, the triazine ring-containing polymer solution (C) (4.2 g) obtained in Synthesis Example 3, and the additive [A-1] (0.12 g), and the mixture was stirred for 5 hours to obtain a liquid crystal alignment agent [1] of Example 1. No abnormality such as turbidity or precipitation was observed in this liquid crystal alignment agent, and it was confirmed that the resin component was uniformly dissolved.

<Examples 2 to 6, Comparative Examples 1 and 2>
In Example 1, liquid crystal alignment agents [2] to [6] of Examples 2 to 6 and liquid crystal alignment agents [7] and [8] of Comparative Examples 1 and 2 were obtained in the same manner as in Example 1, except that the blending amounts were changed to those shown in Table 1 below. No abnormalities such as turbidity or precipitation were observed in these liquid crystal alignment agents, and it was confirmed that the resin components were uniformly dissolved.

(Measurement of refractive index)
The liquid crystal alignment agents of Examples 1 to 6 and Comparative Examples 1 and 2 obtained above were spin-coated on a silicon substrate, baked on a hot plate at 70°C for 90 seconds, and then baked in an infrared heating furnace at 230°C for 20 minutes to prepare a liquid crystal alignment agent-coated Si substrate with a film thickness of 100 nm.

Next, the refractive index was measured using M-2000 manufactured by J.A. Woollam Japan, and the refractive index at 550 nm was compared.
The results of measuring the refractive index in Examples 1 to 6 and Comparative Examples 1 and 2 are shown in Table 2 below.

(Transmittance Measurement)
The liquid crystal alignment agents of Examples 1 to 6 and Comparative Examples 1 and 2 obtained above were spin-coated on a quartz substrate, baked on a hot plate at 70°C for 90 seconds, and then baked in an infrared heating furnace at 230°C for 20 minutes to prepare a liquid crystal alignment agent-coated quartz substrate with a film thickness of 100 nm.

Next, the transmittance in the visible light region (380 nm to 780 nm) was measured using a quartz substrate before application of the liquid crystal alignment agent as a reference using a UV-2600 manufactured by Shimadzu Corporation. After that, the average transmittance Y in the XYZ color system defined by the CIE was calculated and used as the average luminous transmittance.
The transmittance measurement results for Examples 1 to 6 and Comparative Examples 1 and 2 are shown in Table 2 below.

As shown in Table 2, it was confirmed that the refractive index in Comparative Examples 1 and 2 was 1.64 or less, whereas Examples 1 to 6 showed a high refractive index of 1.66 or more. It was also confirmed that Examples 1 to 6 showed a high average luminous transmittance of 95% or more while maintaining a high refractive index.

(Evaluation of voltage holding ratio)
<Preparation of Liquid Crystal Cell for Evaluating Voltage Holding Ratio>
The liquid crystal alignment agents of Examples 1 to 6 and Comparative Examples 1 and 2 obtained above were spin-coated on the ITO surface of a glass substrate (length 30 mm, width 40 mm, thickness 0.7 mm) with ITO that had been washed with pure water and IPA (isopropyl alcohol), baked on a hot plate at 70° C. for 90 seconds, and then baked in an infrared heating furnace at 230° C. for 20 minutes to prepare a polyimide-coated substrate with a film thickness of 100 nm.

Two substrates coated with a liquid crystal alignment agent were prepared using the above method, 4 μm bead spacers were sprayed onto the liquid crystal alignment film surface of one of the substrates, and then a thermosetting sealant (XN-1500T manufactured by Kyoritsu Chemical Industry Co., Ltd.) was printed on top of the bead spacers. Next, the other substrate was attached to the previous substrate with the side on which the liquid crystal alignment film was formed facing inward, and the sealant was cured to prepare an empty cell. PSA polymerizable compound-containing liquid crystal MLC-3023 (manufactured by Merck) was injected into this empty cell by the reduced pressure injection method to prepare a liquid crystal cell. The voltage retention rate of this liquid crystal cell was measured.

Next, while a DC voltage of 15 V was applied to the liquid crystal cell, the liquid crystal cell was irradiated with 10 J/ ^cm2 UV light through a 325 nm cut filter from the outside (also referred to as a primary PSA treatment). The UV illuminance was measured using a UV-MO3A manufactured by ORC Corporation.

After that, in order to inactivate any unreacted polymerizable compound remaining in the liquid crystal cell, the cell was irradiated with UV (UV lamp: FLR40SUV32/A-1) for 30 minutes using a Toshiba Lighting & Technology Corporation UV-FL irradiation device with no voltage applied (referred to as secondary PSA treatment). The voltage retention rate was then measured.

<Measurement of voltage holding ratio>
Using the liquid crystal cell prepared above, a voltage of 1 V was applied for 60 μs in a hot air circulating oven at 60° C., and the voltage was measured 1667 msec later, and the voltage retention ratio (VHR) was calculated to determine how much the voltage was retained. To measure the voltage retention ratio, VHR-1 manufactured by Toyo Corporation was used.
The measurement results of the voltage holding ratio in Examples 1 to 6 and Comparative Examples 1 and 2 are shown in Table 3 below.

As shown in Table 3, in Examples 1 to 6, the VHR after the secondary PSA treatment was all around 90%, which was confirmed to be equivalent to that of the comparative example.
It was confirmed that the liquid crystal elements of Examples 1 to 6 exhibited a voltage holding ratio that was good for practical use.

(Evaluation of pretilt angle)
<Preparation of Liquid Crystal Cell for Pretilt Angle Evaluation>
The liquid crystal alignment agents of Examples 1 to 6 and Comparative Examples 1 and 2 obtained above were spin-coated on the ITO surfaces of an ITO electrode substrate (length 35 mm, width 30 mm, thickness 0.5 mm) having an ITO electrode pattern with a pixel size of 200 μm × 600 μm and a line/space of 3 μm each, which had been washed with pure water and IPA (isopropyl alcohol), and a glass substrate (length 35 mm, width 30 mm, thickness 0.7 mm) with an ITO electrode patterned with a photospacer having a height of 3.2 μm, and baked on a hot plate at 70 ° C. for 90 seconds, and then baked in an infrared heating furnace at 230 ° C. for 20 minutes or 60 minutes to prepare polyimide-coated substrates with a film thickness of 100 nm.
The ITO electrode substrate on which this ITO electrode pattern is formed is divided into four areas in a cross-checkered pattern so that each of the four areas can be driven separately.

Two polyimide-coated substrates were prepared using the above method, and a thermosetting sealant (XN-1500T, manufactured by Kyoritsu Chemical Industry Co., Ltd.) was printed on top of them. The other substrate was then attached to the previous substrate with the side on which the liquid crystal alignment film had been formed facing inward, and the sealant was then cured to create an empty cell. PSA polymerizable compound-containing liquid crystal MLC-3023 (manufactured by Merck) was injected into this empty cell using the reduced pressure injection method to create a liquid crystal cell. The voltage retention rate of this liquid crystal cell was measured.

Next, while a DC voltage of 15 V was applied to the liquid crystal cell, the liquid crystal cell was irradiated with 10 J/ ^cm2 UV light through a 325 nm cut filter from the outside (also referred to as a primary PSA treatment). The UV illuminance was measured using a UV-MO3A manufactured by ORC Corporation.

After that, in order to inactivate any unreacted polymerizable compound remaining in the liquid crystal cell, the cell was irradiated with UV (UV lamp: FLR40SUV32/A-1) for 30 minutes with no voltage applied using a UV-FL irradiation device manufactured by Toshiba Lighting & Technology Corporation (referred to as secondary PSA treatment). The pretilt angle was then measured.

<Measurement of pretilt angle>
The pretilt angle of the liquid crystal cell for evaluating the pretilt angle prepared above was measured using an LCD analyzer (LCA-LUV42A manufactured by Meiryo Technica Co., Ltd.) The pretilt angle difference was calculated by subtracting the pretilt angle measured using the polyimide-coated substrate baked for 60 minutes from the pretilt angle measured using the polyimide-coated substrate baked for 20 minutes in an infrared heating furnace at 230°C.
The measurement results of the pretilt angles in Examples 1 to 6 and Comparative Examples 1 and 2 are shown in Table 4 below.

As shown in Table 4, it was confirmed that Examples 1 to 6 exhibited tilt angle characteristics equivalent to those of Comparative Examples 1 and 2, and exhibited good vertical alignment properties.

Claims (13)

A liquid crystal aligning agent comprising the following components (A) and (B):
the component (A) is at least one polymer (A) selected from the group consisting of polyimide precursors and polyimides which are imidized products of the polyimide precursors ,
The component (B) is a polymer (B) that contains a repeating unit structure represented by the following formula (1), has at least one triazine ring terminal, and at least a part of the triazine ring terminal is blocked with an arylamino group having a crosslinking group :
The polymer (A) is obtained by using a diamine component containing an aromatic diamine and a tetracarboxylic acid component containing a tetracarboxylic acid dianhydride represented by the following formula (S4) or a derivative thereof :
Liquid crystal alignment agent.

(R and R′ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or an aralkyl group;
Ar represents at least one selected from the group represented by formulas (2) to (12).

(Any hydrogen atom on the aromatic ring of formulas (2) to (12) may be substituted,
R ¹² represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms;
W ¹ and W ² each independently represent a single bond, -CR ⁹⁵ R ⁹⁶ - (R ⁹⁵ and R ⁹⁶ each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms (which may be joined together to form a ring)), -C(=O)-, -O-, -S-, -S(=O)-, -SO ₂ -, or -NR ⁹⁷ - (R ⁹⁷ represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a phenyl group);
^X1 and ^X2 each independently represent a single bond, an alkylene group having 1 to 10 carbon atoms, or a group represented by _-Y1 -Ph- _Y2- (Ph represents a phenylene group, any hydrogen atom on the phenylene group may be substituted, and _Y1 and _Y2 each independently represent a single bond or an alkylene group having 1 to 10 carbon atoms).

(X represents a structure selected from the group consisting of the following (x-1) to (x-13).)

(R ¹ to R ⁴ each independently represent a hydrogen atom, a methyl group, an ethyl group, a propyl group, a chlorine atom, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group. R ⁵ and R ⁶ each represent a hydrogen atom or a methyl group. j and k each represent an integer of 0 or 1. A ₁ and A ₂ each independently represent a single bond, -O-, -CO-, -COO-, phenylene, sulfonyl, or an amide bond. *1 represents a bond bonded to one acid anhydride group, and *2 represents a bond bonded to the other acid anhydride group.) The liquid crystal aligning agent according to claim 1 , wherein the arylamino group having a crosslinking group of the polymer (B) is represented by formula (15):

(In the formula, R ¹⁵ represents a bridging group.) The liquid crystal alignment agent according to any one of claims 1 to 2, wherein the crosslinking group of the polymer (B) is a hydroxy-containing group or a (meth)acryloyl-containing group. The crosslinking group of the polymer (B) is one or more selected from a hydroxy group, a hydroxymethyl group, a 2-hydroxyethyl group, a (meth)acryloyloxymethyl group, a (meth)acryloyloxyethyl group, and a group represented by the following formula (i-2) to formula (i-3). The liquid crystal aligning agent according to any one of claims 1 to 3.

The liquid crystal alignment agent according to any one of claims 1 to 4, further comprising a portion of the triazine ring terminals of the polymer (B) blocked with an unsubstituted arylamino group. The polymer (A) is obtained using a diamine component containing at least one diamine (a) selected from the group consisting of structures represented by the following formulas (S1) to (S3): The liquid crystal aligning agent according to any one of claims 1 to 5.

( ^X1 and ^X2 each independently represent a single bond, -( _CH2 ) _a- (a is an integer of 1 to 15), -CONH-, -NHCO-, -CON( _CH3 )-, -NH-, -O-, -COO-, -OCO-, or -(( _CH2 ) _a1 - _A1 ) _m1- (a1 is an integer of 1 to 15, _A1 represents an oxygen atom or -COO-, and _m1 is an integer of 1 to 2. When _m1 is 2, a1 and _A1 each independently have the above definition). ^G1 and G Each of ² independently represents a divalent cyclic group selected from a divalent aromatic group having 6 to 12 carbon atoms and a divalent alicyclic group having 3 to 8 carbon atoms. Any hydrogen atom on the cyclic group may be substituted with an alkyl group having 1 to 3 carbon atoms, an alkoxyl group having 1 to 3 carbon atoms, a fluorine atom-containing alkyl group having 1 to 3 carbon atoms, a fluorine atom-containing alkoxy group having 1 to 3 carbon atoms, or a fluorine atom. Each of m and n independently represents an integer of 0 to 3, and m+n is an integer of 1 to 6. R ¹ represents an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxyalkyl group having 2 to 20 carbon atoms, and any hydrogen atom forming R ¹ may be substituted with a fluorine atom.

( ^X3 represents a single bond, -CONH-, -NHCO-, -CON( _CH3 )-, -NH-, -O-, _-CH2O- , -COO- or -OCO-. ^R2 represents an alkyl group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms, and any hydrogen atom forming ^R2 may be substituted with a fluorine atom.)

( ^X4 represents -CONH-, -NHCO-, -O-, -CH ₂ O-, -COO- or -OCO-. ^R3 represents a structure having a steroid skeleton.) The liquid crystal aligning agent according to claim 6 , wherein the diamine (a) is a diamine represented by the following formula (d1) or formula (d2):

(X represents a divalent organic group selected from a single bond, -O-, -C( _CH3 ) _2- , -NH-, -CO-, -( _CH2 ) _m- , -SO2-, -O-( _CH2 ) _m -O-, -O-C( _CH3 ) _2- , -CO-( _CH2 )m-, -NH-( _CH2 ) _m- , _-SO2- ( _CH2 ) _m- , -CONH-( _CH2 ) _m- , -CONH-( _CH2 ) _m -NHCO-, and -COO-( _{CH2 ) m} -OCO-. _m is an integer of 1 to 8. Y represents any of the structures represented by formulae (S1) to (S3). In formula (d2), the two Ys may be the same or different.) The tetracarboxylic dianhydride or its derivative represented by the formula (S4) is a tetracarboxylic dianhydride or its derivative represented by the formula (x-1) to (x-7), (x-11) to (x-13), wherein X is a tetracarboxylic dianhydride or its derivative represented by the formula (x-1) to (x-7), (x-11) to (x-13). The liquid crystal aligning agent according to claim 1 . The liquid crystal aligning agent according to any one of claims 1 to 8 , wherein the content ratio of the (A) component and the (B) component is 10/90 to 90/10 in terms of a mass ratio of [(A) component]/[(B) component]. A liquid crystal alignment film formed by using the liquid crystal aligning agent according to any one of claims 1 to 9 . A liquid crystal display device comprising the liquid crystal alignment film according to claim 10 . A method for producing a liquid crystal display element, comprising a step of applying the liquid crystal aligning agent according to any one of claims 1 to 9 onto a substrate. The method for producing a liquid crystal display element according to claim 12, comprising applying the liquid crystal aligning agent according to any one of claims 1 to 9 onto a pair of substrates having conductive films to form coating films, arranging the coating films so as to face each other via a layer of liquid crystal molecules to form a liquid crystal cell, and irradiating the liquid crystal cell with light while applying a voltage between the conductive films of the pair of substrates .

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