JP2023131106A - Liquid crystal alignment agent, liquid crystal alignment film, and liquid crystal element - Google Patents

Abstract

To provide a liquid crystal alignment agent that can form a liquid crystal alignment film having a high dynamic strength, reduces the occurrence of an afterimage due to accumulation of residual electric charges, reduces the generation of bright spots, and can obtain a liquid crystal element having high transmittance.SOLUTION: A polymer (P) having a structural unit derived from a compound represented by the formula (1) is contained in a liquid crystal alignment agent. In the formula (1), Ar1 is a divalent aromatic ring group. X1 is a single bond, -O-, -S-, or -NR1-. Ar2, Ar3, and Y1 satisfy a requirement (i), (ii), or (iii). When X1 is a single bond, Y1 is coupled to Ar1 with carbon atoms. (i) Ar2 is a divalent aromatic ring group, Ar3 is a monovalent aromatic ring group, and Y1 is a divalent organic group having one or more carbon atoms. (ii) Ar2 and Ar3 represent a nitrogen-containing aromatic condensed ring structure. Y1 is a divalent organic group having one or more carbon atoms. (iii) Ar2 is a divalent aromatic ring group. Ar3 and Y1 are a divalent group including a nitrogen-containing aromatic condensed ring structure.SELECTED DRAWING: None

Description

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

Liquid crystal elements are used in a wide range of applications, from relatively large display devices such as liquid crystal televisions and information displays to small display devices such as smartphones. The performance of a liquid crystal element is determined by various characteristics such as the orientation of the liquid crystal, the size of the pretilt angle, and the voltage holding rate. In order to improve the performance of liquid crystal elements, in addition to improving liquid crystal materials, improvements have been made to liquid crystal alignment films for aligning liquid crystals in a certain direction.

In a liquid crystal element, when charges are accumulated in a liquid crystal cell, it may be visually recognized by an observer as an afterimage (DC afterimage), and the display quality of the liquid crystal element may deteriorate. Therefore, one of the characteristics required of the liquid crystal alignment film is that there is little charge accumulation.

Therefore, various techniques have been proposed to suppress the accumulation of charge in a liquid crystal cell and improve the display quality of a liquid crystal element (for example, see Patent Document 1). Patent Document 1 describes that a polyamic acid obtained by reacting a diamine compound containing a nitrogen-containing diamine such as N4,N4'-bis(4-aminophenyl)-benzidine with a tetracarboxylic dianhydride is used as a liquid crystal aligning agent. It is disclosed that the amount of accumulated charge can be reduced by incorporating the compound into the compound.

Japanese Patent Application Publication No. 2008-107811

In recent years, as the definition of liquid crystal elements has become higher, requirements for the quality of liquid crystal elements have become even stricter. Therefore, it is required to reduce as much as possible the charge accumulated in the liquid crystal element by applying a voltage, to reduce the occurrence of afterimages as much as possible, and to have a high transmittance of the liquid crystal element. In addition, in consideration of application of the rubbing method, improvement of liquid crystal alignment and voltage holding rate, suppression of decrease in yield, etc., the organic film formed using the liquid crystal aligning agent is required to have sufficiently high strength.

In the manufacturing process of liquid crystal alignment films and liquid crystal elements, decomposition products such as polymers may be generated when a load due to heat or light is applied to the liquid crystal alignment film or the organic film that becomes the liquid crystal alignment film. Further, due to the generation of such thermal decomposition products and photodecomposition products, display defects (bright spots) may occur in the obtained liquid crystal element. In order to further improve the quality of liquid crystal elements, it is required to suppress the generation of such bright spots.

An object of the present invention is to form a liquid crystal alignment film with high mechanical strength, to obtain a liquid crystal element that is less likely to cause afterimages due to accumulation of residual charges, has fewer bright spots, and has high transmittance. An object of the present invention is to provide a liquid crystal aligning agent.

As a result of intensive research, the present inventors discovered that the above-mentioned problems could be solved by using a diamine having a specific structure, and the present invention was completed. Specifically, the present invention provides the following means.

（式（１）中、Ａｒ^１は２価の芳香環基である。Ｘ^１は、単結合、－Ｏ－、－Ｓ－又は－ＮＲ^１－である。Ｒ^１は、水素原子、炭素数１～３のアルキル基又は熱脱離性基である。Ａｒ^２、Ａｒ^３及びＹ^１は、下記の要件（ｉ）、（ｉｉ）又は（ｉｉｉ）を満たす。ただし、Ｘ^１が単結合の場合、Ｙ^１は炭素原子でＡｒ^１に結合している。
（ｉ）Ａｒ^２は２価の芳香環基である。Ａｒ^３は１価の芳香環基である。Ｙ^１は、炭素数１以上の２価の有機基である。
（ｉｉ）Ａｒ^２及びＡｒ^３は、互いに合わせられて、Ａｒ^２及びＡｒ^３が結合する窒素原子と共に構成される窒素含有芳香族縮合環構造を表す。Ｙ^１は、炭素数１以上の２価の有機基である。
（ｉｉｉ）Ａｒ^２は２価の芳香環基である。Ａｒ^３及びＹ^１は、互いに合わせられて、Ａｒ^３及びＹ^１が結合する窒素原子と共に構成される窒素含有芳香族縮合環構造を含む２価の基である。） <1> A liquid crystal aligning agent containing a polymer (P) having a structural unit derived from a compound represented by the following formula (1).

(In formula (1), Ar ¹ is a divalent aromatic ring group. X ¹ is a single bond, -O-, -S-, or -NR ¹ -. ^{R 1} is a hydrogen atom, the number of carbon atoms 1 to 3 alkyl groups or thermally releasable groups. Ar ² , Ar ³ and Y ¹ satisfy the following requirements (i), (ii) or (iii). However, if X ¹ is a single bond In the case, Y ¹ is bonded to Ar ¹ through a carbon atom.
(i) Ar ² is a divalent aromatic ring group. Ar ³ is a monovalent aromatic ring group. Y ¹ is a divalent organic group having 1 or more carbon atoms.
(ii) Ar ² and Ar ³ are taken together to represent a nitrogen-containing aromatic condensed ring structure formed with the nitrogen atom to which Ar ² and Ar ³ are bonded. Y ¹ is a divalent organic group having 1 or more carbon atoms.
(iii) Ar ² is a divalent aromatic ring group. Ar ³ and Y ¹ are a divalent group containing a nitrogen-containing aromatic condensed ring structure formed together with the nitrogen atom to which Ar ³ and Y ¹ are bonded. )

<2> A liquid crystal aligning film formed using the liquid crystal aligning agent of <1> above.
<3> A liquid crystal element comprising the liquid crystal alignment film of <2> above.

According to the liquid crystal aligning agent of the present invention, it is possible to form a liquid crystal aligning film with high mechanical strength, and to obtain a liquid crystal element that is less likely to cause afterimages and bright spots and has high transmittance.

《Liquid crystal alignment agent》
Each component contained in the liquid crystal aligning agent of the present disclosure and other components optionally blended as necessary will be explained below.

In this specification, the term "hydrocarbon group" includes a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. The term "chain hydrocarbon group" refers to a straight chain hydrocarbon group and a branched hydrocarbon group that do not contain a cyclic structure in the main chain and are composed only of a chain structure. However, the s-chain hydrocarbon group may be saturated or unsaturated. "Alicyclic hydrocarbon group" means a hydrocarbon group containing only an alicyclic hydrocarbon structure as a ring structure and not containing an aromatic ring structure. However, the alicyclic hydrocarbon group does not need to be composed only of an alicyclic hydrocarbon structure, and includes those having a chain structure as a part thereof. "Aromatic hydrocarbon group" means a hydrocarbon group containing an aromatic ring structure as a ring structure. However, the aromatic hydrocarbon group does not need to be composed only of an aromatic ring structure, and may include a chain structure or an alicyclic hydrocarbon structure as a part thereof. "Aromatic ring" is meant to include aromatic hydrocarbon rings and aromatic heterocycles. The term "organic group" refers to an atomic group obtained by removing any hydrogen atoms from a carbon-containing compound (ie, an organic compound).

The ``main chain'' of a polymer refers to the ``trunk'' portion of the polymer consisting of the longest chain of atoms. It is permissible for this "trunk" portion to include a ring structure. For example, "having a specific structure in the main chain" means that the specific structure constitutes a part of the main chain. "Side chain" refers to a portion branched from the "trunk" of the polymer. The term "tetracarboxylic acid derivative" includes tetracarboxylic dianhydride, tetracarboxylic diester, and tetracarboxylic diester dihalide.

（式（１）中、Ａｒ^１は２価の芳香環基である。Ｘ^１は、単結合、－Ｏ－、－Ｓ－又は－ＮＲ^１－である。Ｒ^１は、水素原子、炭素数１～３のアルキル基又は熱脱離性基である。Ａｒ^２、Ａｒ^３及びＹ^１は、下記の要件（ｉ）、（ｉｉ）又は（ｉｉｉ）を満たす。ただし、Ｘ^１が単結合の場合、Ｙ^１は炭素原子でＡｒ^１に結合している。
（ｉ）Ａｒ^２は２価の芳香環基である。Ａｒ^３は１価の芳香環基である。Ｙ^１は、炭素数１以上の２価の有機基である。
（ｉｉ）Ａｒ^２及びＡｒ^３は、互いに合わせられて、Ａｒ^２及びＡｒ^３が結合する窒素原子と共に構成される窒素含有芳香族縮合環構造を表す。Ｙ^１は、炭素数１以上の２価の有機基である。
（ｉｉｉ）Ａｒ^２は２価の芳香環基である。Ａｒ^３及びＹ^１は、互いに合わせられて、Ａｒ^３及びＹ^１が結合する窒素原子と共に構成される窒素含有芳香族縮合環構造を含む２価の基である。） The liquid crystal aligning agent of the present disclosure contains a polymer (P) having a structural unit derived from a compound represented by the following formula (1) (hereinafter also referred to as "specific diamine").

(In formula (1), Ar ¹ is a divalent aromatic ring group. X ¹ is a single bond, -O-, -S-, or -NR ¹ -. ^{R 1} is a hydrogen atom, the number of carbon atoms 1 to 3 alkyl groups or thermally releasable groups. Ar ² , Ar ³ and Y ¹ satisfy the following requirements (i), (ii) or (iii). However, if X ¹ is a single bond In the case, Y ¹ is bonded to Ar ¹ through a carbon atom.
(i) Ar ² is a divalent aromatic ring group. Ar ³ is a monovalent aromatic ring group. Y ¹ is a divalent organic group having 1 or more carbon atoms.
(ii) Ar ² and Ar ³ are taken together to represent a nitrogen-containing aromatic condensed ring structure formed with the nitrogen atom to which Ar ² and Ar ³ are bonded. Y ¹ is a divalent organic group having 1 or more carbon atoms.
(iii) Ar ² is a divalent aromatic ring group. Ar ³ and Y ¹ are a divalent group containing a nitrogen-containing aromatic condensed ring structure formed together with the nitrogen atom to which Ar ³ and Y ¹ are bonded. )

Below, the polymer (P) and other optionally blended components will be explained in detail. Note that each component may be used singly or in combination of two or more, unless otherwise specified.

<Polymer (P)>
In the above formula (1), when Ar ² , Ar ³ and Y ¹ satisfy the above requirement (i), the divalent aromatic ring group represented by Ar ¹ or Ar ² may be selected from the ring portion of the aromatic ring. This is a group from which two hydrogen atoms have been removed. Examples of aromatic rings include aromatic hydrocarbon rings such as benzene ring, naphthalene ring, anthracene ring, and biphenyl ring; pyrrole ring, imidazole ring, pyrazole ring, pyridine ring, pyrimidine ring, pyridazine ring, pyrazine ring, quinoline ring, and isoquinoline ring. , a nitrogen-containing aromatic heterocycle such as a benzimidazole ring, a carbazole ring, and an acridine ring. Among these, Ar ¹ and Ar ² are preferably groups having a structure in which two hydrogen atoms are removed from the ring portion of a benzene ring or pyridine ring, and more preferably a substituted or unsubstituted phenylene group. A substituent may be introduced into the aromatic ring of the aromatic ring group represented by Ar ¹ and Ar ² in addition to the primary amino group. Examples of the substituent include an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, and a halogen atom.

The monovalent aromatic ring group represented by Ar ³ is a group obtained by removing one arbitrary hydrogen atom from the ring portion of an aromatic ring. Specific examples of the aromatic ring include the same groups as those exemplified in the description of the divalent aromatic ring groups represented by Ar ¹ and Ar ² . Ar ³ is preferably a group having a structure in which one hydrogen atom is removed from the ring portion of a benzene ring, naphthalene ring or pyridine ring, and more preferably a substituted or unsubstituted phenyl group. Examples of the substituent that Ar ³ has on the ring portion include an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, and a halogen atom.

When R ¹ is an alkyl group having 1 to 3 carbon atoms, the alkyl group may be linear or branched. A thermally releasable group is a group that is eliminated by heat to produce a hydrogen atom. When R ¹ is a thermally releasable group, examples of R ¹ include a carbamate structure-containing group, an amide structure-containing group, an imide structure-containing group, a sulfonamide structure-containing group, and the like. Among these, carbamate structure-containing groups are preferred in terms of their high thermal releasability. Specific examples include tert-butoxycarbonyl group, benzyloxycarbonyl group, 1,1-dimethyl-2-haloethyloxycarbonyl group, allyloxycarbonyl group, 2-(trimethylsilyl)ethoxycarbonyl group, 9-fluorenyl group. Examples include methyloxycarbonyl group and allyloxycarbonyl group. Among these, a tert-butoxycarbonyl group (Boc group) is particularly preferable because it has excellent thermal removability and can reduce the amount of the deprotected portion remaining in the film.

R ¹ is preferably a hydrogen atom, a methyl group, or a thermally releasable group, and more preferably a hydrogen atom, since a liquid crystal alignment film with high mechanical strength can be obtained.

The divalent organic group represented by Y ¹ is a divalent hydrocarbon group having 1 to 20 carbon atoms; any methylene group possessed by the hydrocarbon group is -O-, -S-, -CO-, - Number of carbon atoms replaced with COO-, -OCO-, -NR-, -NR ¹⁰ CO-, -CONR ¹⁰ -, -NR ¹⁰ COO-, -OCONR ¹⁰ -, -NR ¹⁰ -CO-NR ¹¹ -, etc. 1 to 20 divalent groups (However, R ¹⁰ and R ¹¹ are each independently a hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms, or a thermally releasable group. The same applies hereinafter.) ; Examples include groups having a heterocyclic structure.

When Y ¹ is a divalent hydrocarbon group having 1 to 20 carbon atoms, examples of the hydrocarbon group include a chain hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, Examples include a hydrogen group and an aromatic hydrocarbon group having 6 to 20 carbon atoms. Specific examples of these include, as divalent chain hydrocarbon groups having 1 to 20 carbon atoms, methylene group, ethylene group, 1,3-propanediyl group, 1,2-propanediyl group, 2,2-propanediyl group, Alkanediyl groups such as diyl group, 1,4-butanediyl group, 1,3-butanediyl group, 1,2-butanediyl group, 2,2-butanediyl group, pentanediyl group; ethendiyl group, 1,3-propendiyl group, 1 , 4-butenediyl group, 1,5-pentenediyl group; and alkynediyl groups such as ethynediyl group, 1,3-propynediyl group, 1,4-butenediyl group, 1,5-pentendiyl group, and the like.

Examples of the divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include monocyclic saturated alicyclic hydrocarbon groups such as cyclopropanediyl group, cyclobutanediyl group, cyclopentanediyl group, and cyclohexanediyl group; norbornanediyl group; polycyclic alicyclic saturated hydrocarbon groups such as adamantanediyl, tricyclodecanediyl, and tetracyclododecanediyl groups; Cyclic alicyclic unsaturated hydrocarbon groups; polycyclic alicyclic saturated hydrocarbon groups such as norbornenediyl group and tricyclodecenediyl group; and the like. In addition, the divalent alicyclic hydrocarbon group represented by ^Y1 includes a divalent aliphatic cyclic group such as a cyclopropanediyl group and a cyclopentanediyl group, and the above-mentioned divalent chain hydrocarbon group. may be a group to which is bonded.

Examples of the divalent aromatic hydrocarbon group having 6 to 20 carbon atoms include arylene groups such as phenylene group, tolylene group, xylylene group, naphthylene group, and anthrylene group; * ¹ -Ar ⁴ -R ²² - or * ¹ -R A group represented by ²² -Ar ⁴ - (where Ar ⁴ is a substituted or unsubstituted phenylene group, R ²² is a divalent chain hydrocarbon group, "* ¹ " is a group represented by X ¹ in formula (1)) (represents a bond), etc.

Note that when X ¹ is a single bond, Y ¹ is bonded to Ar ¹ through a carbon atom. When Y ¹ is bonded to Ar ¹ through a carbon atom, specific examples of Y ¹ include, for Ar ¹ , a saturated or unsaturated chain hydrocarbon group, a saturated or unsaturated alicyclic hydrocarbon group; group, an aromatic hydrocarbon group, or a group bonded with a carbonyl group. Further specific examples of Y ¹ when Y ¹ is bonded to Ar ¹ through a carbon atom include * ² -CH ₂ -R ²³ -, * ² -CH=CH-R ²³ -, * ² -C ≡C-R ²³ -, * ² -CO-R ²³ -, * ² -Ph ¹ -R ²³ -, * ² -Cy ¹ -R ²³ - (Ph ¹ is a substituted or unsubstituted phenylene group, Cy ¹ is a substituted or unsubstituted cycloalkylene group, R ²³ is a single bond or a divalent organic group, and "* ² " represents a bond with Ar ¹ ). Specific examples of the divalent organic group represented by ^R23 include a divalent hydrocarbon group having 1 to 18 carbon atoms; any methylene group possessed by the hydrocarbon group is -O-, -S-, -CO -, -COO-, -OCO-, -NR-, -NR ¹⁰ CO-, -CONR ¹⁰ -, -NR ¹⁰ COO-, -OCONR ¹⁰ -, -NR ¹⁰ -CO-NR ¹¹ -, etc. A divalent group having 1 to 18 carbon atoms; a group having a heterocyclic structure, and the like.

From the viewpoint of sufficiently reducing the residual charge accumulated in the liquid crystal element and increasing the transmittance of the liquid crystal element, Y ¹ in the above formula (1) has a chain structure in part or in whole, and Ar ³ is It is preferable that the nitrogen atom is bonded to the nitrogen atom in a chain structure. In this case, the chain structure of the bonding site with the nitrogen atom (ie, the end of Y ¹ on the Ar ² side) that Y ¹ has may be saturated or unsaturated, and may be linear or branched. From the viewpoint of further increasing the effect of reducing accumulated residual charges and improving the transmittance, Y ¹ is bonded to the nitrogen atom to which Ar ³ is bonded via a divalent linear hydrocarbon group. This is preferable, and it is more preferable that they are bonded through a linear alkanediyl group.

From the viewpoint of suppressing the occurrence of afterimages and bright spots in the liquid crystal element as much as possible, the group represented by "-X ¹ -Y ¹ -" is a group in which X ¹ is -O-, -S- or -NR ¹ -. Y ¹ is a divalent organic group, or X ¹ is a single bond and part or all of Y ¹ has a chain structure, and Y ¹ has a chain structure and is bonded to Ar ¹ . Preferably. When X ¹ is a single bond, Y ¹ is bonded to Ar ¹ with a divalent linear hydrocarbon group, from the viewpoint of further increasing the effect of reducing accumulated residual charges and improving the transmittance. It is preferable that they are bonded together, and it is more preferable that they are bonded through a linear alkanediyl group.

Among the groups represented by "-X ¹ -Y ¹ -", Y ¹ is preferably a divalent chain group. Specifically, Y ¹ is a divalent chain hydrocarbon group having 1 to 20 carbon atoms, or any methylene group possessed by the chain hydrocarbon group is -O-, -S-, -CO-, - Carbon number 1 replaced with COO-, -OCO-, -NR-, -NR ¹⁰ CO-, -CONR ¹⁰ -, -NR ¹⁰ COO-, -OCONR ¹⁰ - or -NR ¹⁰ -CO-NR ¹¹ - It is preferably a divalent group having 1 to 20 carbon atoms, or an alkanediyl group having 1 to 20 carbon atoms, or any methylene group that the alkanediyl group has -O-, -S-, -CO-, -COO-, having 1 to 20 carbon atoms replaced with -OCO-, -NR-, -NR ¹⁰ CO-, -CONR ¹⁰ -, -NR ¹⁰ COO-, -OCONR ¹⁰ - or -NR ¹⁰ -CO-NR ¹¹ - More preferably, it is a divalent group. Note that R ¹⁰ and R ¹¹ have the same meanings as above.

When Y ¹ is a divalent chain group, the number of carbon atoms in Y ¹ is preferably 10 or less, more preferably 4 or less, from the viewpoint of obtaining a liquid crystal alignment film with sufficiently high mechanical strength. . Further, from the viewpoint of reducing accumulated charges in the liquid crystal alignment film and the liquid crystal element, the number of carbon atoms in Y ¹ is preferably 1 or more, more preferably 2 or more. When X ¹ is a single bond and Y ¹ is a divalent chain group, from the viewpoint of stability of the compound, Y ¹ preferably has 2 or more carbon atoms.

Among the above, X ¹ is preferably -O- or -S-, and more preferably -O-, since the transmittance of the obtained liquid crystal alignment film can be sufficiently increased.

When Ar ² , Ar ³ and Y ¹ satisfy the above requirement (ii), Ar ² and Ar ³ are combined with each other to form a nitrogen-containing aromatic fused ring formed with the nitrogen atom to which Ar ² and Ar ³ are bonded. Examples of the structure include a carbazole ring structure and an acridine ring structure. Among these, the nitrogen-containing aromatic fused ring structure is preferably a carbazole ring structure. In the nitrogen-containing aromatic condensed ring structure, the nitrogen-containing aromatic condensed ring may have a substituent. Examples of the substituent include a methyl group, an ethyl group, a hydroxyl group, a halogen atom, and the like.
Regarding specific examples and preferred examples of the divalent aromatic ring group represented by Ar ¹ , the group represented by X ¹ , and the divalent organic group represented by Y ¹ , Ar ² , Ar ³ and Y ¹ are Examples include the same groups as those explained in the case where the above requirement (i) is satisfied.

When Ar ² , Ar ³ and Y ¹ satisfy the above requirement (iii), Ar ³ and Y ¹ are combined with each other to form a nitrogen-containing aromatic fused ring formed with the nitrogen atom to which Ar ³ and Y ¹ are bonded. Regarding the specific examples and preferred examples of the nitrogen-containing aromatic condensed ring structure in the divalent group containing the structure (hereinafter also referred to as "divalent group ArY"), Ar ² , Ar ³ and Y ¹ are the above-mentioned Examples include the same groups as those explained in the case satisfying requirement (ii). In the divalent group ArY, the nitrogen-containing aromatic fused ring may be directly bonded to X ¹ or Ar ¹ , or the nitrogen-containing aromatic fused ring may be bonded to X ¹ or Ar ¹ via a divalent linking group. You may do so. The divalent linking group preferably has a partially or entirely chain structure, more preferably a linear alkanediyl group, and even more preferably a linear alkanediyl group having 1 to 4 carbon atoms.
Regarding specific examples and preferred examples of the divalent aromatic ring group represented by Ar ¹ or Ar ² and the group represented by X ¹ , when Ar ² , Ar ³ and Y ¹ satisfy the above requirement (i) Examples include groups similar to those explained in .

Specific examples of the specific diamine include compounds represented by each of the following formulas (1-1) to (1-26).

In the polymer (P), the content ratio of structural units derived from the specific diamine may be 0.5 mol% or more with respect to the total structural units derived from the monomers constituting the polymer (P). It is preferably 5 mol% or more, more preferably 10 mol% or more. Moreover, it is preferable that the content ratio of the structural unit derived from the specific diamine is 50 mol% or less with respect to all the structural units derived from the monomers constituting the polymer (P).

The polymer (P) may be any polymer containing a structural unit derived from a specific diamine, and the type of its main skeleton is not particularly limited. Examples of the polymer (P) include polyamic acid, polyamic acid ester, polyimide, polyamide, polyamideimide, polyurea, polyenamine, and the like. The polymer (P) is particularly selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, since it is possible to form a liquid crystal alignment film with high mechanical strength and to obtain a highly reliable liquid crystal element. It is preferable that it is at least one type. That is, the polymer (P) is preferably a polymer containing a structural unit derived from a tetracarboxylic acid derivative and a structural unit derived from a diamine compound.

[Polyamic acid]
When the polymer (P) is a polyamic acid, the polyamic acid (hereinafter also referred to as "polyamic acid (P)") can be prepared by reacting a tetracarboxylic dianhydride with a diamine compound containing a specific diamine. Obtainable.

・Tetracarboxylic dianhydride Examples of the tetracarboxylic dianhydride used in the synthesis of polyamic acid (P) include aliphatic tetracarboxylic dianhydride and aromatic tetracarboxylic dianhydride. . Examples of aliphatic tetracarboxylic dianhydrides include chain tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides.

Specific examples of these include, as chain tetracarboxylic dianhydrides, 1,2,3,4-butanetetracarboxylic dianhydride, ethylenediaminetetraacetic dianhydride, and the like. Examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentyl acetic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1 ,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexanetetracarboxylic dianhydride, 3 , 5,6-tricarboxy-2-carboxymethylnorbornane-2:3,5:6-dianhydride and the like.

Examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene) diphthalic anhydride, ethylene glycol bisanhydrotrimate, and 4,4'-carbonyl diphthalate. Examples include acid anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, and 3,3',4,4'-biphenyl ether tetracarboxylic dianhydride. Furthermore, in the synthesis of polyamic acid (P), the tetracarboxylic dianhydride described in JP-A-2010-97188 can be used.

(Diamine compound)
The diamine compound used in the synthesis of polyamic acid (P) may be only a specific diamine, or a combination of a specific diamine and a diamine different from the specific diamine (hereinafter also referred to as "other diamine"). Good too. Other diamines include aliphatic diamines, aromatic diamines, diaminoorganosiloxanes, and the like. Aliphatic diamines include chain diamines and alicyclic diamines.

Specific examples of other diamines include metaxylylene diamine, hexamethylene diamine, and the like as chain diamines. Examples of the alicyclic diamine include 1,4-diaminocyclohexane and 4,4'-methylenebis(cyclohexylamine).

（式（Ｄ－１）中、Ｒ^１１及びＲ^１２は、それぞれ独立して、アルカンジイル基である。Ｒ^１３は、水素原子、炭素数１～３のアルキル基又は熱脱離性基である。ｎ１は１～３の整数である。ｎ１が２又は３の場合、複数のＲ^１２は互いに同一又は異なり、複数のＲ^１３は互いに同一又は異なる。）
で表される化合物等の主鎖型ジアミン；
ヘキサデカノキシ－２，４－ジアミノベンゼン、オクタデカノキシ－２，４－ジアミノベンゼン、オクタデカノキシ－２，５－ジアミノベンゼン、コレスタニルオキシ－３，５－ジアミノベンゼン、コレステリルオキシ－３，５－ジアミノベンゼン、コレスタニルオキシ－２，４－ジアミノベンゼン、コレステリルオキシ－２，４－ジアミノベンゼン、３，５－ジアミノ安息香酸コレスタニル、３，５－ジアミノ安息香酸コレステリル、３，５－ジアミノ安息香酸ラノスタニル、３，６－ビス（４－アミノベンゾイルオキシ）コレスタン、３，６－ビス（４－アミノフェノキシ）コレスタン、４－（４’－トリフルオロメトキシベンゾイロキシ）シクロヘキシル－３，５－ジアミノベンゾエート、１，１－ビス（４－（（アミノフェニル）メチル）フェニル）－４－ブチルシクロヘキサン、３，５－ジアミノ安息香酸＝５ξ－コレスタン－３－イル、下記式（Ｅ－１）

（式（Ｅ－１）中、Ｘ^I及びＸ^IIは、それぞれ独立して、単結合、－Ｏ－、＊－ＣＯＯ－又は＊－ＯＣＯ－（ただし、「＊」はＸ^Ｉとの結合手を示す。）である。Ｒ^Ｉは、炭素数１～３のアルカンジイル基である。Ｒ^ＩＩは、単結合又は炭素数１～３のアルカンジイル基である。Ｒ^ＩＩＩは、炭素数１～２０のアルキル基、アルコキシ基、フルオロアルキル基、又はフルオロアルコキシ基である。ａは０又は１である。ｂは０～３の整数である。ｃは０～２の整数である。ｄは０又は１である。ただし、１≦ａ＋ｂ＋ｃ≦３である。）
で表される化合物等の側鎖型ジアミン等が挙げられる。ジアミノオルガノシロキサンとしては、１，３－ビス（３－アミノプロピル）－テトラメチルジシロキサン等が挙げられる。 Aromatic diamines include p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylethane, 4-aminophenyl-4-aminobenzoate, 4,4'-diaminoazobenzene, 3,5- Diaminobenzoic acid, 1,5-bis(4-aminophenoxy)pentane, 1,2-bis(4-aminophenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,6-bis(4-aminophenoxy)propane -aminophenoxy)hexane, 6,6'-(pentamethylenedioxy)bis(3-aminopyridine), N,N'-di(5-amino-2-pyridyl)-N,N'-di(tert- butoxycarbonyl)ethylenediamine, bis[2-(4-aminophenyl)ethyl]hexanedioic acid, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenethylurea, 2,2 -bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis( 4-aminophenoxy)biphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-(phenylenediisopropylidene)bisaniline, 2,6-diaminopyridine, 2,4-diaminopyrimidine, 3 , 6-diaminocarbazole, N-methyl-3,6-diaminocarbazole, 3,6-diaminoacridine, the following formula (D-1)

(In formula (D-1), R ¹¹ and R ¹² are each independently an alkanediyl group. R ¹³ is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a thermally releasable group. (n1 is an integer from 1 to 3. When n1 is 2 or 3, multiple R ^12s are the same or different from each other, and multiple R ^13s are the same or different from each other.)
Main chain type diamine such as a compound represented by;
Hexadecanoxy-2,4-diaminobenzene, octadecanoxy-2,4-diaminobenzene, octadecanoxy-2,5-diaminobenzene, cholestanyloxy-3,5-diaminobenzene, cholesteryloxy-3,5-diaminobenzene, cholestanil Oxy-2,4-diaminobenzene, cholesteryloxy-2,4-diaminobenzene, cholestanyl 3,5-diaminobenzoate, cholesteryl 3,5-diaminobenzoate, lanostanil 3,5-diaminobenzoate, 3,6-diaminobenzoate Bis(4-aminobenzoyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 4-(4'-trifluoromethoxybenzoyloxy)cyclohexyl-3,5-diaminobenzoate, 1,1-bis (4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 3,5-diaminobenzoic acid = 5ξ-cholestan-3-yl, following formula (E-1)

(In formula (E-1), X ^I and X ^II are each independently a single bond, -O-, *-COO-, or *-OCO- (however, "*" is a bond with X ^I) ). R ^I is an alkanediyl group having 1 to 3 carbon atoms. R ^II is a single bond or an alkanediyl group having 1 to 3 carbon atoms. R ^III is an alkanediyl group having 1 to 3 carbon atoms. 20 alkyl group, alkoxy group, fluoroalkyl group, or fluoroalkoxy group.a is 0 or 1.b is an integer of 0 to 3.c is an integer of 0 to 2.d is 0 or 1. However, 1≦a+b+c≦3.)
Examples include side chain diamines such as the compound represented by: Examples of the diaminoorganosiloxane include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane.

Examples of the compound represented by the above formula (D-1) include compounds represented by each of the following formulas (D-1-1) to (D-1-3). Examples of the compound represented by the above formula (E-1) include compounds represented by each of the following formulas (E-1-1) to (E-1-4). Other diamines further include compounds represented by the following formulas (F-1) to (F-7). As other diamines, one type can be used alone or two or more types can be used in combination. In the formula, "Boc" represents a tert-butoxycarbonyl group (the same applies hereinafter).

When synthesizing polyamic acid (P), the amount of specific diamine used is preferably 1 mol% or more, and preferably 5 mol% or more, based on the total amount of diamine compounds used for synthesizing polyamic acid (P). The content is more preferably 10 mol% or more, even more preferably 20 mol% or more. By setting the usage amount of the specific diamine within the above range, it is possible to sufficiently obtain the improvement effects of suppressing the generation of bright spots and reducing afterimages in the liquid crystal element.

-Synthesis of polyamic acid Polyamic acid (P) can be obtained by reacting a tetracarboxylic dianhydride and a diamine compound together with a molecular weight regulator if necessary.

In the synthesis reaction of polyamic acid (P), the ratio of tetracarboxylic dianhydride and diamine compound to be used is 0.00% of the acid anhydride group of the tetracarboxylic dianhydride per 1 equivalent of amino group of the diamine compound. A ratio of 2 to 2 equivalents is preferred. Examples of molecular weight modifiers include acid monoanhydrides such as maleic anhydride, phthalic anhydride, and itaconic anhydride; monoamine compounds such as aniline, cyclohexylamine, and n-butylamine; and monoisocyanate compounds such as phenyl isocyanate and naphthylisocyanate. can be mentioned. The proportion of the molecular weight regulator to be used is preferably 20 parts by mass or less based on the total of 100 parts by mass of the tetracarboxylic dianhydride and diamine compound used.

In the synthesis reaction of polyamic acid (P), the reaction temperature is preferably -20°C to 150°C, and the reaction time is preferably 0.1 to 24 hours. Examples of the organic solvent used in the reaction include aprotic polar solvents, phenol solvents, alcohol solvents, ketone solvents, ester solvents, ether solvents, halogenated hydrocarbons, hydrocarbons, etc. . Among these, N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphorotriamide, m-cresol, xylenol and halogen It is possible to use one or more selected from the group consisting of chemical phenols as a reaction solvent, or to use a mixture of one or more of these and other organic solvents (for example, butyl cellosolve, diethylene glycol diethyl ether, etc.). preferable. The amount of organic solvent used is preferably such that the total amount of the tetracarboxylic dianhydride and diamine compound is 0.1 to 50% by mass based on the total amount of the reaction solution.

When a polymer solution obtained by dissolving polyamic acid (P) is obtained by the above polymerization, this polymer solution may be used as it is for preparing a liquid crystal aligning agent, and the polyamic acid (P) contained in the polymer solution may be used as is. may be isolated and then used for preparing a liquid crystal aligning agent.

[Polyamic acid ester]
When the polymer (P) is a polyamic acid ester, the polyamic acid ester can be prepared by, for example, [I] a method of reacting a polyamic acid (P) with an esterifying agent, [II] a method of reacting a tetracarboxylic acid diester with a diamine compound, etc. It can be obtained by a method of reacting [III] tetracarboxylic acid diester dihalide with a diamine compound, etc. The polyamic acid ester may have only an amic acid ester structure, or may be a partially esterified product in which an amic acid structure and an amic acid ester structure coexist. The reaction solution obtained by dissolving the polyamic acid ester may be used as it is for preparing a liquid crystal aligning agent. Alternatively, the polyamic acid ester contained in the reaction solution may be isolated and the isolated polyamic acid ester may be used for preparing a liquid crystal aligning agent.

[Polyimide]
When the polymer (P) is a polyimide, the polyimide (hereinafter also referred to as "polyimide (P)") can be obtained, for example, by dehydrating and ring-closing polyamic acid (P) and imidizing it. Polyimide (P) may be a complete imidized product obtained by dehydrating and ring-closing all of the amic acid structure possessed by its precursor polyamic acid (P), or it may be a complete imidized product obtained by dehydrating and ring-closing only a part of the amic acid structure. , a partially imidized product in which an amic acid structure and an imide ring structure coexist may be used. The imidization rate of polyimide (P) is preferably 20 to 99%, more preferably 30 to 90%. The imidization rate is the ratio of the number of imide ring structures to the total number of amic acid structures and the number of imide ring structures of polyimide, expressed as a percentage. Here, a part of the imide ring may be an isoimide ring.

Dehydration and ring closure of polyamic acid (P) is preferably carried out by dissolving polyamic acid (P) in an organic solvent, adding a dehydrating agent and a dehydration ring closure catalyst to this solution, and heating as necessary. In this method, as the dehydrating agent, for example, acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used. The amount of the dehydrating agent used is preferably 0.01 to 20 mol per 1 mol of the amic acid structure of the polyamic acid (P). As the dehydration ring-closing catalyst, for example, tertiary amines such as pyridine, collidine, lutidine, and triethylamine can be used. The amount of the dehydration ring-closing catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used.

Examples of the organic solvent used in the dehydration ring closure reaction include the organic solvents exemplified as those used in the synthesis of polyamic acid (P). The reaction temperature of the dehydration ring closure reaction is preferably 0 to 180°C. The reaction time is preferably 1.0 to 120 hours. The reaction solution containing polyimide (P) obtained by the dehydration ring closure reaction of polyamic acid (P) may be used as it is for preparing a liquid crystal aligning agent. Alternatively, polyimide (P) may be isolated from the reaction solution, and the isolated polyimide (P) may be used for preparing a liquid crystal aligning agent. Polyimide (P) can also be obtained by dehydration ring closure of polyamic acid ester.

The solution viscosity of the polymer (P) is preferably one having a solution viscosity of 10 to 800 mPa·s, and 15 to 500 mPa·s when the solution has a concentration of 10% by mass. It is more preferable. Note that the solution viscosity (mPa・s) is for a polymer solution with a concentration of 10% by mass prepared using a good solvent for the polymer (P) (for example, γ-butyrolactone, N-methyl-2-pyrrolidone, etc.). This is a value measured at 25°C using an E-type rotational viscometer.

The weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) of the polymer (P) is preferably 1,000 to 500,000, more preferably 2,000 to 300, It is 000. The molecular weight distribution (Mw/Mn) represented by the ratio of Mw to the number average molecular weight (Mn) in terms of polystyrene measured by GPC is preferably 7 or less, more preferably 5 or less.

The content ratio of the polymer (P) in the liquid crystal aligning agent is preferably 20% by mass or more with respect to the total amount of solid content contained in the liquid crystal aligning agent (i.e., the total mass of components other than the solvent of the liquid crystal aligning agent). , more preferably 40% by mass or more, and still more preferably 60% by mass or more.

Here, in order to suppress afterimages caused by charge accumulation, it is important to avoid afterimages that are observed immediately (i.e., in the short term) after the voltage application is removed (hereinafter also referred to as "short-term afterimages") and after the voltage application is removed. It is desirable to reduce both afterimages (hereinafter also referred to as "long-term afterimages") that are observed after a sufficient period of time has elapsed (that is, over a long period of time). On the other hand, according to studies by the present inventors, there is a trade-off relationship between short-term afterimages and long-term afterimages, and an attempt to improve one tends to worsen the other. The same applies to long-term afterimages and the transmittance of the liquid crystal element; for example, when attempting to reduce long-term afterimages, the transmittance of the liquid crystal element tends to decrease. On the other hand, according to the present disclosure, by forming a liquid crystal alignment film using the polymer (P), high transmittance can be achieved while reducing both short-term afterimages and long-term afterimages. In addition, the diamine represented by the above formula (1) constituting the polymer (P) has an asymmetrical shape on both sides of the reference axis when the reference axis is placed in a direction crossing the direction in which the main chain extends. It has a structure. Therefore, the polymer (P) containing a structural unit derived from the diamine represented by the above formula (1) has low crystallinity, and even when decomposed products are generated by heat or light, the decomposed products are difficult to crystallize. Conceivable. As a result, it is considered that the liquid crystal aligning agent containing the polymer (P) was able to suppress the generation of bright spots.

<Other ingredients>
In addition to the polymer (P), the liquid crystal aligning agent may contain a component different from the polymer (P) (hereinafter also referred to as "other components") as needed.

[Polymer (Q)]
The liquid crystal aligning agent of the present disclosure may further contain a polymer (hereinafter also referred to as "polymer (Q)") that does not contain a structural unit derived from a specific diamine. The main skeleton of the polymer (Q) is not particularly limited. Examples of the polymer (Q) include polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, polyester, polyenamine, polyurea, polyamide, polyamideimide, polybenzoxazole precursor, polybenzoxazole, cellulose derivative, polyacetal, and Examples include polymers (eg, (meth)acrylic polymers, styrene polymers, maleimide polymers, styrene-maleimide copolymers), and the like. Among these, the polymer (Q) is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, and addition polymer.

When the polymer (Q) is contained in the liquid crystal aligning agent, the content ratio of the polymer (Q) is based on 100 parts by mass of the total amount of the polymer (P) and the polymer (Q) contained in the liquid crystal aligning agent. The amount is preferably 1 part by mass or more, more preferably 2 parts by mass or more. Moreover, the content ratio of the polymer (Q) is preferably 95 parts by mass or less, and 90 parts by mass based on 100 parts by mass of the total amount of the polymer (P) and the polymer (Q) contained in the liquid crystal aligning agent. The following are more preferable.

〔solvent〕
The liquid crystal aligning agent of the present disclosure is preferably prepared as a liquid composition in which the polymer (P) and other components used as necessary are dispersed or dissolved in an appropriate solvent.

As the solvent, organic solvents are preferably used. Specific examples include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, 1,3-dimethyl-2-imidazolidinone, phenol, γ- Butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, diacetone alcohol, 1-hexanol, 2-hexanol, propane-1,2- Diol, 3-methoxy-1-butanol, ethylene glycol monomethyl ether, methyl lactate, ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl acetoacetate, ethyl acetoacetate, ethyl propionate, methylmethoxypropionone ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-i-propyl ether, ethylene glycol-n-butyl ether (butyl cellosolve), ethylene glycol dimethyl ether, ethylene Glycol ethyl 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, diisobutyl ketone, isoamyl propionate, isoamyl isobutyrate, diisopentyl ether, Examples include ethylene carbonate, propylene carbonate, propylene glycol monomethyl ether (PGME), diethylene glycol diethyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol diacetate, cyclopentanone, and cyclohexanone. As the solvent, one type can be used alone or two or more types can be used in combination.

In addition to the above, other components to be added to the liquid crystal aligning agent include, for example, crosslinking agents, antioxidants, metal chelate compounds, curing accelerators, surfactants, fillers, dispersants, photosensitizers, etc. It will be done. The blending ratio of other components can be appropriately selected depending on each compound within a range that does not impair the effects of the present disclosure.

The solid concentration in the liquid crystal aligning agent (the ratio of the total mass of components other than the solvent of the liquid crystal aligning agent to the total mass of the liquid crystal aligning agent) is appropriately selected in consideration of viscosity, volatility, etc. The solid content concentration of the liquid crystal aligning agent is preferably in the range of 1 to 10% by mass. It is suitable that the solid content concentration is 1% by mass or more because a sufficient thickness of the coating film can be ensured and a liquid crystal alignment film exhibiting better liquid crystal alignment properties can be obtained. On the other hand, when the solid content concentration is 10% by mass or less, the coating film can be made to have an appropriate thickness, a liquid crystal alignment film that exhibits good liquid crystal alignment properties is easily obtained, and the viscosity of the liquid crystal alignment agent is moderate. This tends to improve coating properties.

<<Liquid crystal alignment film and liquid crystal element>>
The liquid crystal aligning film of the present disclosure is manufactured using the liquid crystal aligning agent prepared as described above. Moreover, the liquid crystal element of this indication comprises the liquid crystal alignment film formed using the liquid crystal alignment agent demonstrated above. The driving method of the liquid crystal in the liquid crystal element is not particularly limited, and includes, for example, TN type, STN type, VA type (including VA-MVA type, VA-PVA type, etc.), IPS type, FFS type, and OCB (Optically Compensated Bend). It can be applied to various modes such as type, PSA type (Polymer Sustained Alignment), etc. A liquid crystal element can be manufactured, for example, by a method including steps 1 to 3 below. In step 1, the substrate used differs depending on the desired operation mode. Steps 2 and 3 are common to each operation mode.

<Step 1: Formation of coating film>
First, a liquid crystal aligning agent is applied onto a substrate, and a coating film is formed on the substrate, preferably by heating the applied surface. As the substrate, for example, a transparent substrate made of glass such as float glass or soda glass; or plastic such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, or poly(alicyclic olefin) can be used. The transparent conductive film provided on one side of the substrate includes a NESA film (registered trademark of PPG, USA) made of tin oxide (SnO ₂ ) and an ITO film made of indium oxide-tin oxide (In ₂ O ₃ -SnO ₂ ). etc. can be used. When manufacturing a TN type, STN type, or VA type liquid crystal element, two substrates each having a patterned transparent conductive film are used. On the other hand, when manufacturing an IPS type or FFS type liquid crystal element, a substrate provided with comb-shaped patterned electrodes and a counter substrate provided with no electrodes are used.

The method of applying the liquid crystal alignment agent to the substrate is not particularly limited. The liquid crystal alignment agent can be applied to the substrate using, for example, a spin coat method, a printing method (e.g. offset printing method, flexo printing method, etc.), an inkjet method, a slit coat method, a bar coater method, an extrusion die method, or a direct gravure method. This can be carried out by a coater method, a chamber doctor coater method, an offset gravure coater method, an impregnation coater method, an MB coater method, or the like.

After applying the liquid crystal aligning agent, preheating (prebaking) is preferably performed for the purpose of preventing the applied liquid crystal aligning agent from dripping. The prebake temperature is preferably 30 to 200°C, and the prebake time is preferably 0.25 to 10 minutes. Thereafter, a calcination (post-bake) step is performed for the purpose of completely removing the solvent and, if necessary, thermally imidizing the amic acid structure present in the polymer. The firing temperature (post-bake temperature) at this time is preferably 80 to 280°C, more preferably 80 to 250°C. Post-bake time is preferably 5 to 200 minutes. The thickness of the formed film is preferably 0.001 to 1 μm.

<Step 2: Orientation treatment>
When manufacturing a TN-type, STN-type, IPS-type, or FFS-type liquid crystal element, the coating film formed in step 1 is subjected to a treatment (orientation treatment) that imparts liquid crystal alignment ability. Thereby, the ability to orient liquid crystal molecules is imparted to the coating film, and it becomes a liquid crystal alignment film. As the alignment treatment, it is preferable to use a rubbing treatment in which the surface of the coating film formed on the substrate is rubbed with cotton, nylon, etc., or a photoalignment treatment in which the coating film is irradiated with light to impart liquid crystal alignment ability. When manufacturing a vertically aligned liquid crystal element, the coating film formed in step 1 above may be used as it is as a liquid crystal alignment film, or the coating film may be subjected to an alignment treatment in order to further enhance the liquid crystal alignment ability. It's okay. A liquid crystal alignment film suitable for a vertical alignment type liquid crystal element can also be preferably used for a PSA type liquid crystal element.

Light irradiation for photo-alignment can be performed by irradiating the coating film after the post-bake process, by irradiating the coating film after the pre-bake process but before the post-bake process, or by irradiating the coating film after the pre-bake process but before the post-bake process. At least one of these methods can be carried out by irradiating the coating film while the coating film is being heated. As the radiation irradiated to the coating film, for example, ultraviolet rays and visible light including light with a wavelength of 150 to 800 nm can be used. Preferably, it is ultraviolet light containing light with a wavelength of 200 to 400 nm. If the radiation is polarized, it may be linearly polarized or partially polarized. 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 thereof. In the case of non-polarized radiation, the irradiation direction is oblique.

Examples of the light source used include a low-pressure mercury lamp, a high-pressure mercury lamp, a deuterium lamp, a metal halide lamp, an argon resonance lamp, a xenon lamp, and an excimer laser. The radiation dose is preferably 200 to 30,000 J/m ² , more preferably 500 to 10,000 J/m ² . After light irradiation for imparting alignment ability, the substrate surface is treated with water, an organic solvent (e.g., methanol, isopropyl alcohol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, etc.), or a mixture thereof. A cleaning process or a process of heating the substrate may also be performed.

<Step 3: Construction of liquid crystal cell>
A liquid crystal cell is manufactured by preparing two substrates on which liquid crystal alignment films are formed as described above, and disposing a liquid crystal between the two substrates that are arranged facing each other. To manufacture a liquid crystal cell, for example, two substrates are placed facing each other with a gap in between so that the liquid crystal alignment films face each other, and the peripheral parts of the two substrates are bonded together using a sealant, and the surface of the substrate and the sealant are bonded together. Examples include a method in which liquid crystal is injected into a cell gap surrounded by , and the injection hole is sealed, a method using an ODF method, and the like. As the sealant, for example, an epoxy resin containing a hardening agent and aluminum oxide spheres as spacers can be used. Examples of liquid crystals include nematic liquid crystals and smectic liquid crystals, with nematic liquid crystals being preferred.

In the PSA mode, a polymerizable compound (for example, a polyfunctional (meth)acrylate compound, etc.) is filled into the cell gap together with liquid crystal, and after the liquid crystal cell is constructed, a voltage is applied between the conductive films of a pair of substrates. In this step, the liquid crystal cell is irradiated with light. When producing a PSA type liquid crystal element, the proportion of the polymerizable compound used is, for example, 0.01 to 3 parts by weight, preferably 0.05 to 1 part by weight, based on a total of 100 parts by weight of the liquid crystal.

When manufacturing a liquid crystal display device, a polarizing plate is then bonded to the outer surface of the liquid crystal cell. Examples of the polarizing plate include a polarizing plate in which a polarizing film called "H film" in which polyvinyl alcohol is stretched and oriented and absorbs iodine is sandwiched between cellulose acetate protective films, or a polarizing plate made of the H film itself.

The liquid crystal element of the present disclosure can be effectively applied to various uses. Specifically, for example, various display devices such as watches, portable game consoles, word processors, notebook computers, car navigation systems, camcorders, PDAs, digital cameras, mobile phones, smartphones, various monitors, LCD televisions, information displays, etc. , a light control device, a retardation film, etc.

According to the present disclosure described above, the following means are provided.
[Means 1] A liquid crystal aligning agent containing a polymer (P) having a structural unit derived from the compound represented by the above formula (1).
[Means 2] X ¹ in the above formula (1) is -O-, -S-, or -NR ¹ -, or X ¹ is a single bond and part or all of Y ¹ is chain-like. structure, and Y ¹ is bonded to Ar ¹ in a chain structure, the liquid crystal aligning agent as described in [means 1].
[Means 3] Y ¹ in the above formula (1) is a divalent organic group having 1 or more carbon atoms, has a chain structure in part or in whole, and is attached to the nitrogen atom to which Ar ³ is bonded. The liquid crystal aligning agent according to [Means 1] or [Means 2], which is bonded in a chain structure.
[Means 4] The liquid crystal alignment according to any one of [Means 1] to [Means 3], wherein the polymer (P) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide. agent.
[Means 5] The liquid crystal aligning agent according to any one of [Means 1] to [Means 4], which further contains a polymer (Q) that does not have a structural unit derived from the compound represented by the above formula (1). .
[Means 6] The liquid crystal alignment according to [Means 5], wherein the polymer (Q) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, and addition polymer. agent.
[Means 7] A liquid crystal alignment film formed using the liquid crystal aligning agent according to any one of [Means 1] to [Means 6].
[Means 8] A liquid crystal element comprising the liquid crystal alignment film according to [Means 7].

Hereinafter, embodiments will be described in more detail based on Examples, but the present invention should not be interpreted as being limited by the Examples below.

In the following examples, the imidization rate of polyimide in the polymer solution, and the weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer were measured by the following methods. The necessary amounts of the raw material compounds and polymers used in the following examples were ensured by repeating the synthesis on the synthesis scale shown in the following synthesis examples as necessary.

[Imidization rate of polyimide]
A polyimide solution was poured into pure water, and the resulting precipitate was thoroughly dried under reduced pressure at room temperature, then dissolved in deuterated dimethyl sulfoxide, and ¹ H-NMR measurement was performed at room temperature using tetramethylsilane as a reference substance. . From the obtained ¹ H-NMR spectrum, the imidization rate [%] was determined using the following formula (I).
Imidization rate [%] = (1-(A ¹ /(A ² × α))) × 100 … (I)
(In formula (I), ^A1 is the peak area derived from the proton of the NH group that appears around 10 ppm in chemical shift, ^A2 is the peak area derived from other protons, and α is the polymer precursor (polyamic acid ) is the ratio of the number of other protons to one proton of the NH group in ).

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]
Mw and Mn are polystyrene equivalent values measured by GPC under the following conditions.
Column: manufactured by Tosoh Corporation, TSKgelGRCXLII
Solvent: Tetrahydrofuran Temperature: 40℃
Pressure: 68kgf/ ^cm2

The abbreviations of the compounds are as follows. Note that hereinafter, the compound represented by formula (X) may be simply referred to as "compound (X)."
(Tetracarboxylic dianhydride)

(Diamine compound)

(Other monomers)

(Additive)

<Synthesis of polymer>
1. Synthesis of polyamic acid [Synthesis example 1]
95 mol parts of compound (TA-3) and 5 mol parts of compound (TA-8) as tetracarboxylic dianhydride, and 80 mol parts of compound (DA-1) and 20 mol parts of compound (DB-5) as diamine compounds. was dissolved in N-methyl-2-pyrrolidone (NMP) and reacted at room temperature for 6 hours to obtain a solution containing 15% by mass of polyamic acid (this will be referred to as polymer (PI-1)).

[Synthesis Examples 2-10, 12-14, 16-18, 20, 21, 24, 26, 28-30, 32, 33, 35-38]
Polyamic acid (polymer (PI-2) to (PI-10), (PI-12) ~ (PI-14), (PI-16) ~ (PI-18), (PI-20), (PI-21), (PI-24), (PI -26), (PI-28) to (PI-30), (PI-32), (PI-33), (PI-35) to (PI-38)) were obtained.

2. Synthesis of polyimide [Synthesis Example 11]
80 mol parts of compound (DA-11) and 20 mol parts of compound (DB-12) as a diamine compound were dissolved in N-methyl-2-pyrrolidone (NMP), and compound (TA-1) was obtained as a tetracarboxylic dianhydride. 90 parts by mole and 10 parts by mole of compound (TA-3) were added and reacted at 40°C for 24 hours to obtain a solution containing 20% by mass of polyamic acid.
Next, NMP was added to the obtained polymer solution to obtain a solution having a polyamic acid concentration of 10% by mass, pyridine and acetic anhydride were added, and a dehydration ring-closing reaction was performed at 90° C. for 4 hours. After the dehydration ring-closing reaction, the solvent in the system was replaced with fresh NMP to obtain a solution containing 15% by mass of polyimide (this is referred to as polymer (PI-11)) with an imidization rate of about 60%. Ta.

[Synthesis Examples 15, 19, 22, 23, 25, 27, 31, 34]
The same operation as in Synthesis Example 11 was performed except that the types and amounts of the tetracarboxylic dianhydride and diamine compound used were changed as shown in Tables 1 and 2, and polyimide (polymer (PI-15), A solution containing PI-19), (PI-22), (PI-23), (PI-25), (PI-27), (PI-31), (PI-34)) was obtained. The imidization rate of each polymer is also shown in Table 1.

3. Synthesis of polyorganosiloxane [Synthesis Example 39]
A 1000 mL three-necked flask was charged with 100.0 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (a compound represented by the above formula (S-1)), 500 g of methyl isobutyl ketone, and 10.0 g of triethylamine. Mixed at room temperature. Next, 100 g of deionized water was added dropwise from the dropping funnel over 30 minutes, and the mixture was reacted at 80° C. for 6 hours while being mixed under reflux. After the reaction was completed, the organic layer was taken out and washed with a 0.2% by mass ammonium nitrate aqueous solution until the water after washing became neutral, and then the solvent and water were distilled off under reduced pressure. An appropriate amount of methyl isobutyl ketone was added to obtain a 50% by mass solution of a polymer (ESSQ-1) which is a polyorganosiloxane having an epoxy group.
In a 500 mL three-necked flask, 3.10 g of compound (C-1) (20 mol% based on the amount of epoxy groups possessed by polymer (ESSQ-1)) and 3.24 g of compound (C-2) (polymer (ESSQ-1)) were placed in a 500 mL three-necked flask. 1), 1.00 g of tetrabutylammonium bromide, 20.0 g of a polymer (ESSQ-1) containing solution, and 290.0 g of methyl isobutyl ketone were added, and the mixture was heated at 90°C for 18 mol%. Stir for hours. After cooling to room temperature, the liquid separation washing operation was repeated 10 times with distilled water. After that, the organic layer was collected, and after repeating concentration and NMP dilution twice using a rotary evaporator, the solid content concentration was adjusted to 10% by mass using NMP, and the polyorganosiloxane (this was converted into a polymer (PSQ) An NMP solution of -1) was obtained.

4. Synthesis of styrene-maleimide copolymer [Synthesis Example 40]
In a 100 mL two-neck flask under nitrogen, 5.00 g of compound (M-1), 1.05 g of compound (M-2), 4.80 g of compound (M-3), and compound (M-4) were added as polymerization monomers. 2.26 g, 0.39 g of 2,2'-azobis(2,4-dimethylvaleronitrile) as a radical polymerization initiator, 0.39 g of 2,4-diphenyl-4-methyl-1-pentene as a chain transfer agent, and 52.5 mL of N-methyl-2-pyrrolidone (NMP) was added as a solvent, and polymerization was carried out at 70° C. for 6 hours. After reprecipitating in methanol, the precipitate was filtered and vacuum-dried at room temperature for 8 hours to obtain a styrene-maleimide copolymer (referred to as polymer (MI-1)). The weight average molecular weight (Mw) measured in terms of polystyrene by GPC was 30,000, and the molecular weight distribution (Mw/Mn) was 2.

[Synthesis example 41]
In a 100 mL two-neck flask under nitrogen, as polymerization monomers, 10 mole parts of compound (M-5), 10 mole parts of compound (M-6), 30 mole parts of compound (M-7), and 10 mole parts of compound (M-8) were added. molar parts, 20 molar parts of compound (M-9), 20 molar parts of compound (M-10), 2 molar parts of 2,2'-azobis(2,4-dimethylvaleronitrile) as a radical polymerization initiator, and a solvent. 50 mL of tetrahydrofuran was added thereto, and polymerization was carried out at 70° C. for 6 hours. After reprecipitating in methanol, the precipitate was filtered and vacuum-dried at room temperature for 8 hours to obtain a styrene-maleimide copolymer (referred to as polymer (MI-2)). The weight average molecular weight (Mw) measured in terms of polystyrene by GPC was 92,700, and the molecular weight distribution (Mw/Mn) was 4.78.

<Preparation and evaluation of liquid crystal alignment agent>
・FFS type liquid crystal display element [Example 1]
1. Preparation of liquid crystal aligning agent A solution containing the polymer (PI-21) obtained in Synthesis Example 21 was added to a solution containing the polymer (PI-23) obtained in Synthesis Example 23 in terms of solid content. -23): Polymer (PI-21) was added so that the ratio was 70:30 (mass ratio), and the additive (AD-2) was added to the polymer (PI-23) and polymer (PI-21). 3 parts by mass were added to a total of 100 parts by mass. It was diluted with NMP and butyl cellosolve (BC) to obtain a solution with a solvent composition of NMP/BC=80/20 (mass ratio) and a solid content concentration of 3.5% by mass. A liquid crystal aligning agent (AL-1) was prepared by filtering this solution through a filter with a pore size of 0.2 μm.

2. Manufacture of FFS type liquid crystal cell using photo-alignment method A glass substrate (referred to as the first substrate) on which a flat plate electrode (bottom electrode), an insulating layer, and a comb-shaped electrode (top electrode) are laminated on one side in this order, and A glass substrate (referred to as a second substrate) without electrodes was prepared. Next, a liquid crystal alignment agent (AL-1) was applied to the electrode-forming surface of the first substrate and one side of the second substrate using a spinner, and heated (prebaked) on a hot plate at 80° C. for 1 minute. Thereafter, drying (post-bake) was performed for 30 minutes in an oven at 230° C. in which the interior was replaced with nitrogen to form a coating film with an average thickness of 0.1 μm. The obtained coating film was subjected to photo-alignment treatment by irradiating it with 1,000 J/m ² of ultraviolet light including a linearly polarized bright line of 254 nm from the normal direction of the substrate using a Hg-Xe lamp. Note that this irradiation amount is a value measured using a light meter that measures at a wavelength of 254 nm. Next, the coating film subjected to the photo-alignment treatment was heat-treated by heating in a clean oven at 230° C. for 30 minutes to form a liquid crystal alignment film.
Next, for one of the pair of substrates on which the liquid crystal alignment film was formed, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 3.5 μm was applied to the outer edge of the surface having the liquid crystal alignment film by screen printing. Thereafter, the substrates were stacked and pressed together so that the projection direction of the polarization axis onto the substrate surface at the time of light irradiation was antiparallel, and the adhesive was thermally cured at 150° C. for 1 hour. Next, a negative liquid crystal (MLC-6608, manufactured by Merck & Co., Ltd.) was filled between the pair of substrates through a liquid crystal injection port, and then the liquid crystal injection port was sealed with an epoxy adhesive to obtain an optical FFS type liquid crystal cell. Furthermore, in order to remove the fluid orientation at the time of liquid crystal injection, this was heated at 120° C. and then slowly cooled to room temperature. In addition, three or more liquid crystal cells with different amounts of UV irradiation can be manufactured by performing the above series of operations while changing the amount of UV irradiation after post-baking in the range of 100 to 10,000 J/ ^m2. Then, evaluation was performed using a liquid crystal cell with an exposure amount that showed the best alignment characteristics (optimum exposure amount).

3. Evaluation (1) Evaluation of charge accumulation characteristics (high temperature short-term afterimage) 2. The liquid crystal cell manufactured in 1 was placed in an environment of 60° C. and 1 atm. After driving with an alternating current rectangular wave (AC) with a frequency of 30 Hz at a relative transmittance of 100% and setting the luminance difference between any two pixels to 0, one of the pixels is driven with AC driving under backlight illumination of 5000 cd/m ² . A direct current (DC) of 0.1 V was applied only to the pixels for 60 minutes to accumulate charge. When the application of DC 0.1 V was terminated and the drive was returned to AC only with a relative transmittance of 50%, a brightness difference ΔL occurred between the two pixels due to the accumulated charge. It should be noted that the smaller the brightness difference is, the more difficult it is for charge to accumulate at high temperatures, and the better the high-temperature short-term afterimage characteristics are. If the luminance difference ΔL divided by the average luminance of two pixels is less than 1%, it is "very good (◎)", and if it is 1% or more and less than 2%, it is "good (○)". , when it was 2% or more and less than 3%, it was rated "fair (△)", and when it was 3% or more, it was rated "poor (x)". As a result, this example was evaluated as "very good (◎)".

(2) Evaluation of afterimage characteristics (long-term afterimage) 2. above. The liquid crystal cell manufactured in 1 was placed in an environment of 25° C. and 1 atm. After driving with an alternating current rectangular wave (AC) with a frequency of 30 Hz at a relative transmittance of 100% and setting the luminance difference between any two pixels to 0, one of the pixels is driven with AC driving under backlight illumination of 5000 cd/m ² . A direct current (DC) of 0.5 V was applied only to the pixels for 60 minutes to accumulate charge. When the application of DC 0.5 V was terminated and the drive was returned to AC only with a relative transmittance of 50%, a luminance difference ΔL occurred between the two pixels due to the accumulated charge. The change over time in the brightness difference ΔL was observed, and the time from the end of the application of DC 0.5 V until the brightness difference ΔL became 36.8% or less of the initial value was defined as the afterimage erasing time. It should be noted that the shorter this time, the easier the afterimage caused by the accumulated charge disappears, and it can be said that the long-term afterimage characteristics at room temperature are better. The evaluation was "very good (◎)" if the afterimage removal time was less than 10 minutes, "good (○)" if it was 10 minutes or more and less than 20 minutes, and "good (○)" if it was 20 minutes or more but less than 30 minutes. If the test time was longer than 30 minutes, the test result was "fair (△)", and if the test time was longer than 30 minutes, the test was "poor (x)". As a result, this example was evaluated as "particularly good (◎)".

(3) Evaluation of gushing bright spots 2. above. The liquid crystal cell manufactured in the above was observed using a polarizing microscope (ECLIPSE E600WPOL) (manufactured by Nikon Corporation), and bright spots (emerging bright spots) were evaluated. Specifically, a liquid crystal cell was placed between two polarizing plates arranged so that their polarization axes were perpendicular to each other, and the liquid crystal cell was observed using a polarizing microscope with a magnification of 5 times (observation area: approximately 2500 μm x 2500 μm). . It can be said that the smaller the number of bright spots, the less generation of highly crystalline thermal decomposition products and photodecomposition products, which is better. "Excellent (◎)" if the number of bright spots is less than 10; "Good (○)" if the number is 10 or more and less than 50; "Acceptable (△)" if the number is 50 or more and less than 100. A case where there were 100 or more pieces was classified as "defective (x)". As a result, this example was evaluated as "excellent (◎)".

(4) Evaluation of membrane mechanical properties as described in 1 above. The liquid crystal aligning agent (AL-1) prepared above was applied onto a glass substrate using a spinner, and heated (prebaked) for 3 minutes on a hot plate at 110°C. After that, drying (post-bake) for 30 minutes in a 230°C oven with nitrogen purging inside the chamber to form a coating film with an average thickness of 0.08 μm, and measure the haze value of the coating film using a hazemeter. It was measured. Next, this coating film was subjected to rubbing treatment five times using a rubbing machine having a roll wrapped with cotton cloth at a roll rotation speed of 1000 rpm, a stage movement speed of 3 cm/sec, and a nap length of 0.3 mm. Thereafter, the haze value of the liquid crystal alignment film was measured using a haze meter, and the difference (haze change value) from the haze value before the rubbing treatment was calculated. When the haze value of the film before the rubbing process is Hz1 (%) and the haze value of the film after the rubbing process is Hz2 (%), the haze change value is expressed by the following formula (z-2).
Haze change value (%) = Hz2-Hz1...(z-2)
When the haze change value in the liquid crystal alignment film is less than 0.5, it is rated as "excellent (◎)", when it is 0.5 or more and less than 0.8, it is rated as "good (○)", and when it is 0.8 or more and 1. When it was less than 0, it was evaluated as "fair (△)", and when it was 1.0 or more, it was evaluated as "poor (x)". If the haze change value is less than 1.0, it can be said that the film strength is sufficiently high and the rubbing resistance is high, that is, the mechanical properties of the film are good. As a result, in this example, the film strength was evaluated as "excellent (◎)".

(5) Evaluation of transmittance 1 above. The liquid crystal aligning agent (AL-1) prepared above was applied onto a quartz substrate using a spin coater, heated for 1 minute on a hot plate at 80°C, and then heated in an oven at 230°C with nitrogen purging inside for 30 minutes. Heating was performed for a minute to form a coating film with an average thickness of 100 nm. The quartz substrate on which this coating film was formed was measured using an ultraviolet-visible near-infrared spectrophotometer (manufactured by JASCO Corporation, product name "V-670"), using the same type of quartz substrate without the coating film as a reference. , absorption spectra in the ultraviolet and visible light regions were measured. Note that the influence of reflection was suppressed by using P-polarized light using a polarizing filter and setting the incident angle to the substrate at Brewster's angle. "Excellent (◎)" when the transmittance at a wavelength of 400 nm is 98% or more, "Good (○)" when it is 95% or more and less than 98%, and "Good (○)" when it is 90% or more and less than 95%. If it was less than 90%, it was rated as "favorable (x)". As a result, this example was evaluated as "excellent (◎)".

[Examples 2, 4, 5, 9, 10, 12-14, 16, 19, 21 and Comparative Examples 1, 2, 4, 6]
A liquid crystal aligning agent was prepared in the same manner as in Example 1 except that the composition of the liquid crystal aligning agent was changed as shown in Table 3. Further, using the obtained liquid crystal aligning agent, an optical FFS type liquid crystal cell was manufactured in the same manner as in Example 1, and various evaluations were performed. The results are shown in Table 3.

[Example 3]
1. Preparation of liquid crystal alignment agent NMP and butyl cellosolve (BC) were added to the solution containing the polymer (PI-28) obtained in Synthesis Example 28, and the solvent composition was NMP/BC = 80/20 (mass ratio) and the solid content concentration was A 3.5% by mass solution was prepared. A liquid crystal aligning agent (AL-3) was prepared by filtering this solution through a filter with a pore size of 0.2 μm.

2. Manufacture of FFS type liquid crystal cell using rubbing method A first substrate and a second substrate similar to those in Example 1 were prepared. Next, a liquid crystal alignment agent (AL-3) was applied to each of the electrode-forming surface of the first substrate and one side of the second substrate using a spinner, and heated (prebaked) on a hot plate at 110° C. for 3 minutes. Thereafter, drying (post-bake) was performed for 30 minutes in an oven at 230° C. in which the interior was replaced with nitrogen to form a coating film with an average thickness of 0.08 μm. Next, the surface of the coating film was rubbed using a rubbing machine having a roll wrapped with rayon cloth at a roll rotation speed of 1000 rpm, a stage movement speed of 3 cm/sec, and a nap length of 0.3 mm. Thereafter, a pair of substrates having liquid crystal alignment films were obtained by performing ultrasonic cleaning in ultrapure water for 1 minute and then drying in a 100° C. clean oven for 10 minutes.
Next, on a pair of substrates having a liquid crystal alignment film, an epoxy resin adhesive containing aluminum oxide spheres having a diameter of 3.5 μm was applied by screen printing, leaving a liquid crystal injection port at the edge of the surface on which the liquid crystal alignment film was formed. Thereafter, the substrates were stacked and pressure-bonded, and the adhesive was thermally cured at 150° C. for 1 hour. Next, a negative liquid crystal (MLC-6608, manufactured by Merck & Co., Ltd.) was filled into the gap between the pair of substrates through a liquid crystal injection port, and then the liquid crystal injection port was sealed with an epoxy adhesive. Further, in order to eliminate fluid orientation during liquid crystal injection, this was heated at 120° C. and then slowly cooled to room temperature to produce a liquid crystal cell (rubbing FFS type liquid crystal cell). Note that when the pair of substrates were superimposed, the rubbing method for each substrate was antiparallel.

3. Evaluation 1 above. The liquid crystal alignment agent prepared in 2. and the above 2. Various evaluations were performed in the same manner as in Example 1 using the liquid crystal cell manufactured in Example 1. The evaluation results are shown in Table 3.

[Examples 6 to 8, 11, 15, 17, 18, 20 and Comparative Examples 3, 5, 7, 8]
A liquid crystal aligning agent was prepared in the same manner as in Example 3 except that the composition of the liquid crystal aligning agent was changed as shown in Table 3. Further, using the obtained liquid crystal aligning agent, a rubbed FFS type liquid crystal cell was manufactured in the same manner as in Example 3, and various evaluations were performed. The evaluation results are shown in Table 3.

・PSA type liquid crystal display element [Example 22]
1. Preparation of liquid crystal alignment agent Add 5 parts by mass of additive (AD-4) to 100 parts by mass of polymer (PI-32) to the solution containing the polymer (PI-32) obtained in Synthesis Example 32, The solution was diluted with NMP and BC to obtain a solution with a solvent composition of NMP/BC=50/50 (mass ratio) and a solid content concentration of 3.5% by mass. A liquid crystal aligning agent (AL-30) was prepared by filtering this solution through a filter with a pore size of 0.2 μm.

2. Production of PSA type liquid crystal cell (1) Preparation of liquid crystal composition To 10 g of nematic liquid crystal (manufactured by Merck & Co., Ltd., MLC-6608), 5% by mass of a liquid crystalline compound represented by the following formula (L1-1) and 0.3% by mass of a photopolymerizable compound represented by formula (L2-1) was added and mixed to obtain a liquid crystal composition LC1.

(2) Production of liquid crystal cell The liquid crystal aligning agent (AL-30) prepared above was applied onto the transparent electrode surface of a glass substrate with a transparent electrode made of an ITO film using a spinner, and then heated on a hot plate at 80°C for 1 to 3 minutes. After prebaking for a minute, the solvent was removed by heating at 200° C. for 1 hour in an oven purged with nitrogen to form a coating film (liquid crystal alignment film) with a thickness of 0.08 μm. This coating film was rubbed using a rubbing machine having a roll wrapped with rayon cloth at a roll rotation speed of 400 rpm, a stage movement speed of 3 cm/sec, and a nap length of 0.1 mm. Thereafter, a substrate having a liquid crystal alignment film was obtained by performing ultrasonic cleaning in ultrapure water for 1 minute, and then drying in a 100° C. clean oven for 10 minutes. This operation was repeated to obtain a pair (two sheets) of substrates each having a liquid crystal alignment film. Note that this rubbing treatment is a weak rubbing treatment performed for the purpose of controlling the collapse of the liquid crystal and performing alignment division in a simple method.
After applying an epoxy resin adhesive containing aluminum oxide spheres with a diameter of 3.5 μm to the outer periphery of the surface of one of the above substrates having the liquid crystal alignment film, the liquid crystal alignment film surfaces of the pair of substrates were made to face each other. , they were overlapped and pressed together, and heated at 150° C. for 1 hour to heat cure the adhesive. Next, after filling the gap between the substrates with the liquid crystal composition LC1 through the liquid crystal injection port, the liquid crystal injection port was sealed with an epoxy adhesive, and the liquid crystal composition was heated at 150° C. for 10 hours to remove the fluid orientation during injection of the liquid crystal. After heating for a minute, the mixture was slowly cooled to room temperature.
Next, AC 10V with a frequency of 60Hz was applied between the electrodes to the obtained liquid crystal cell, and while the liquid crystal was driving, 50,000 J of ultraviolet rays were applied using an ultraviolet irradiation device using a metal halide lamp as a light source. The irradiation was performed at a dose of /m ² . Note that this irradiation amount is a value measured using a light meter that measures at a wavelength of 365 nm. In this way, a PSA type liquid crystal cell was manufactured.

3. Evaluation 1 above. The liquid crystal alignment agent prepared in 2. and the above 2. Various evaluations were performed in the same manner as in Example 1 using the liquid crystal cell manufactured in Example 1. The evaluation results are shown in Table 4.

[Examples 23 to 26 and Comparative Examples 9 to 12]
A liquid crystal aligning agent was prepared in the same manner as in Example 22 except that the composition of the liquid crystal aligning agent was changed as shown in Table 4. Moreover, using the obtained liquid crystal aligning agent, a PSA type liquid crystal cell was manufactured in the same manner as in Example 22, and various evaluations were performed. The evaluation results are shown in Table 4.

・Optical vertical type liquid crystal display element [Example 27]
1. Preparation of liquid crystal alignment agent The polymer (MI-1) obtained in Synthesis Example 40 was added to the solution containing the polymer (PI-1) obtained in Synthesis Example 1 in terms of solid content. Polymer (MI-1) was added in an amount of 10 parts by mass to 90 parts by mass, and diluted with NMP and BC so that the solvent composition was NMP/BC = 80/20 (mass ratio) and the solid content concentration was A 3.5% by mass solution was prepared. A liquid crystal aligning agent (AL-39) was prepared by filtering this solution through a filter with a pore size of 0.2 μm.

2. Manufacture of optical vertical type liquid crystal cell (UV2A) The above 1. The liquid crystal alignment agent (AL-39) prepared above was applied using a spinner, and prebaked for 1 minute on a hot plate at 80°C. Thereafter, it was heated at 230° C. for 1 hour in an oven whose interior was replaced with nitrogen to form a coating film with a thickness of 0.1 μm. Next, the surface of this coating film was irradiated with 1,000 J/ ^m2 of polarized ultraviolet light including a 313 nm bright line using a Hg-Xe lamp and a Glan-Taylor prism from a direction inclined at 40° from the normal line of the substrate to improve liquid crystal alignment. granted. The same operation was repeated to create a pair (two sheets) of substrates each having a liquid crystal alignment film.
After applying an epoxy resin adhesive containing aluminum oxide spheres with a diameter of 3.5 μm to the outer periphery of the surface of one of the above substrates having the liquid crystal alignment film, the liquid crystal alignment film surfaces of the pair of substrates were made to face each other. Each substrate was pressed so that the projection direction of the optical axis of ultraviolet rays onto the substrate surface was antiparallel, and the adhesive was thermally cured at 150° C. for 1 hour. Next, a negative liquid crystal (MLC-6608, manufactured by Merck & Co., Ltd.) was filled into the gap between the substrates through a liquid crystal injection port, and then the liquid crystal injection port was sealed with an epoxy adhesive. Furthermore, in order to remove the fluid orientation at the time of liquid crystal injection, this was heated at 130° C. and then slowly cooled to room temperature.

3. Evaluation 1 above. The liquid crystal alignment agent prepared in 2. and the above 2. Various evaluations were performed in the same manner as in Example 1 using the liquid crystal cell manufactured in Example 1. The evaluation results are shown in Table 5.

[Example 28 and Comparative Examples 13 and 14]
A liquid crystal aligning agent was prepared in the same manner as in Example 27 except that the composition of the liquid crystal aligning agent was changed as shown in Table 5. Further, using the obtained liquid crystal aligning agent, a vertical optical liquid crystal cell was manufactured in the same manner as in Example 27, and various evaluations were performed. The evaluation results are shown in Table 5.

From the above results, it is possible to form a liquid crystal alignment film with high mechanical strength, and to obtain a liquid crystal element with high transmittance, which is less likely to cause afterimages and bright spots, using a liquid crystal aligning agent containing polymer (P). has become clear.

Claims (8)

A liquid crystal aligning agent containing a polymer (P) having a structural unit derived from a compound represented by the following formula (1).

(In formula (1), Ar ¹ is a divalent aromatic ring group. X ¹ is a single bond, -O-, -S-, or -NR ¹ -. ^{R 1} is a hydrogen atom, the number of carbon atoms 1 to 3 alkyl groups or thermally releasable groups. Ar ² , Ar ³ and Y ¹ satisfy the following requirements (i), (ii) or (iii). However, if X ¹ is a single bond In the case, Y ¹ is bonded to Ar ¹ through a carbon atom.
(i) Ar ² is a divalent aromatic ring group. Ar ³ is a monovalent aromatic ring group. Y ¹ is a divalent organic group having 1 or more carbon atoms.
(ii) Ar ² and Ar ³ are taken together to represent a nitrogen-containing aromatic condensed ring structure formed with the nitrogen atom to which Ar ² and Ar ³ are bonded. Y ¹ is a divalent organic group having 1 or more carbon atoms.
(iii) Ar ² is a divalent aromatic ring group. Ar ³ and Y ¹ are a divalent group containing a nitrogen-containing aromatic condensed ring structure formed together with the nitrogen atom to which Ar ³ and Y ¹ are bonded. ) In the above formula (1), X ¹ is -O-, -S- or -NR ¹ -, or X ¹ is a single bond and part or all of Y ¹ is a chain structure, The liquid crystal aligning agent according to claim 1, wherein Y ¹ is bonded to Ar ¹ in a chain structure. Y ¹ in the above formula (1) is a divalent organic group having 1 or more carbon atoms, has a chain structure partially or completely, and has a chain structure with respect to the nitrogen atom to which Ar ³ is bonded. The liquid crystal aligning agent according to claim 1, which is bonded. The liquid crystal aligning agent according to claim 1, wherein the polymer (P) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide. The liquid crystal aligning agent according to claim 1, further comprising a polymer (Q) that does not have a structural unit derived from the compound represented by the above formula (1). The liquid crystal aligning agent according to claim 5, wherein the polymer (Q) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, and addition polymer. A liquid crystal aligning film formed using the liquid crystal aligning agent according to any one of claims 1 to 6. A liquid crystal element comprising the liquid crystal alignment film according to claim 7.