JP7782192B2 - Liquid crystal alignment agent, liquid crystal alignment film and liquid crystal element - Google Patents

Description

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

Liquid crystal elements are widely used in televisions, mobile devices, and various monitors. As their applications become more diverse, even higher quality liquid crystal elements are required. This has led to improvements in drive systems and element structures, as well as improvements in the liquid crystal alignment film, one of the components of liquid crystal elements.

When electric charge accumulates within the liquid crystal cells of a liquid crystal element, it is perceived by the viewer as an afterimage (DC afterimage), reducing the display quality of the liquid crystal element. Therefore, one of the characteristics required of a liquid crystal alignment film is low charge accumulation. Possible causes of charge accumulation within the liquid crystal cell include the application of asymmetric positive and negative voltages due to AC drive and the absorption of backlight light by the liquid crystal alignment film. DC afterimages are particularly likely to occur in FFS (Fringe Field Switching) type liquid crystal display elements, which have an asymmetric electrode structure.

A variety of technologies have been proposed to suppress charge accumulation within liquid crystal cells and improve the display quality of liquid crystal elements (see, for example, Patent Documents 1 and 2). Patent Document 1 discloses reducing accumulated charge by incorporating 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, into a liquid crystal aligning agent. Patent Document 2 discloses that incorporating a polymer obtained from a diamine having a structure in which a carbazole structure and a benzene ring are bonded via an amino group into a liquid crystal aligning agent results in a liquid crystal alignment film that quickly releases accumulated charge and is less likely to flicker during operation.

Japanese Patent Application Laid-Open No. 2008-107811 International Publication No. 2018/110354

To meet the recent demand for even higher performance, there is a need for liquid crystal alignment films that can further reduce the accumulation of charge within liquid crystal cells and more quickly relieve any residual charge that does accumulate. Liquid crystal alignment films also need to be highly transparent.

The present invention has been made in consideration of the above-mentioned problems, and its main object is to provide a liquid crystal alignment agent that can produce a liquid crystal alignment film that is highly transparent, has little charge accumulation, and quickly relaxes any accumulated residual charge.

The present invention employs the following measures to solve the above problems.

<1> A liquid crystal aligning agent containing a compound (P) having a partial structure (A) represented by the following formula (1):
*-Y ¹ -A ¹ -A ² -Y ² -*...(1)
(In formula (1), A ¹ and A ² are each independently a divalent group having a fused ring structure in which an aromatic ring is fused to the 2,3-position and the 4,5-position of at least one heteroaromatic ring selected from the group consisting of a pyrrole ring, a furan ring, and a thiophene ring. However, in A ¹ and A ² , at least one carbon atom of the aromatic ring constituting the fused ring structure is bonded to each other by a single bond. Y ¹ and Y ² are each independently a carbon atom, an oxygen atom, a sulfur atom, or a divalent organic group bonded to the fused ring structure in A ¹ or A ² via * ⁵ -NR ⁵ -CO-, or * ² -NR ⁴ -* ³ . R ⁴ is a hydrogen atom or a monovalent organic group, or is bonded to another group and represents a part of a ring structure formed together with the nitrogen atom to which R ⁴ is bonded. R ⁵ is a hydrogen atom or a monovalent organic group. "* ² " and "* ^"5 " represents a bond bonded to the fused ring structure in ^A1 or ^A2 . "* ³ " represents a bond bonded to -CO-. "*" represents a bond.)

<2> A liquid crystal alignment film formed using the liquid crystal aligning agent according to <1> above.
<3> A liquid crystal element comprising the liquid crystal alignment film according to <2> above.
<4> A polymer having at least one selected from the group consisting of a partial structure represented by the following formula (5) and a partial structure represented by the following formula (6):
(In formulas (5) and (6), ^X1 is a tetravalent aliphatic hydrocarbon group. ^X2 is a divalent organic group represented by the following formula (7) or formula (8). ^R8 , ^R9 , ^R10 , and ^R11 are each independently a hydrogen atom or a monovalent organic group having 1 to 8 carbon atoms.)
(In formula (7), R ¹ is a halogen atom, a hydroxy group, or a monovalent organic group, or a fused ring structure formed by combining multiple R ^1s in the formula with the ring to which they are bonded. Y ⁵ is a divalent organic group bonded to the fused ring structure in the formula via a carbon atom. a1 is an integer of 0 to 3. When multiple R ^1s are present in the formula, the multiple R ^1s may be the same or different. Multiple Y ^5s in the formula may be the same or different. Multiple a1s in the formula may be the same or different. "*" represents a bond.)
(In formula (8), ^R2 is a halogen atom, a hydroxy group, or a monovalent organic group. ^R3 is a hydrogen atom or a monovalent organic group. ^Y6 is a single bond or a divalent organic group bonded to the fused ring structure in the formula via a carbon atom, an oxygen atom, a sulfur atom, or * ⁵ - ^NR5 -CO-. ^R5 is a hydrogen atom or a monovalent organic group. * ⁵ represents a bond to the fused ring structure in the formula. a2 is an integer of 0 to 3. When there are multiple ^R2s in the formula, the multiple ^R2s are the same or different. Multiple ^Y6s in the formula are the same or different. Multiple a2s in the formula are the same or different. * represents a bond.)

The liquid crystal aligning agent of the present invention makes it possible to obtain a liquid crystal alignment film with high transparency. It also makes it possible to obtain a liquid crystal alignment film with little charge accumulation and with which accumulated residual charge is quickly released.

FIG. 1 shows the results of measuring the ¹ H-NMR spectrum of the diamine (DA-1) obtained in Synthesis Example 1. FIG. 1 shows the results of measuring the ¹³ C-NMR spectrum of the diamine (DA-1) obtained in Synthesis Example 1. FIG. 10 shows the transmission spectra of Examples 20 to 23. FIG. 10 is a graph showing the transmission spectra of Comparative Examples 7 to 11. FIG. 1 shows the molecular structures and molecular orbitals (HOMO and LUMO) of the bissuccinimides of Examples 20 to 23 and Comparative Examples 7 to 11.

Matters related to the aspects of the present disclosure will be described in detail below. In this specification, the term "hydrocarbon group" includes chain hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. A "chain hydrocarbon group" refers to a straight-chain hydrocarbon group or a branched hydrocarbon group that does not contain a cyclic structure in the main chain and is composed solely of a chain structure. However, it may be saturated or unsaturated. An "alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic hydrocarbon structure as a ring structure and does not contain an aromatic ring structure. However, it does not have to be composed solely of an alicyclic hydrocarbon structure, and may also contain a chain structure as part of it. An "aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as a ring structure. However, it does not have to be composed solely of an aromatic ring structure, and may contain a chain structure or an alicyclic hydrocarbon structure as part of it.

The term "aliphatic hydrocarbon group" encompasses both linear hydrocarbon groups and alicyclic hydrocarbon groups. A "heteroaromatic group" refers to a group formed by removing n hydrogen atoms (n is an integer) from the ring portion of an aromatic heterocycle. However, when a heteroaromatic group has multiple rings, it includes groups formed by removing n hydrogen atoms from the same ring and groups formed by removing n hydrogen atoms from different rings. The "main chain" of a polymer refers to the longest "trunk" portion of the atomic chain of the polymer. The "side chain" of a polymer refers to the portion branching from the "trunk" of the polymer. An "organic group" refers to an atomic group formed by removing any hydrogen atoms from a carbon-containing compound (i.e., an organic compound).

Liquid crystal alignment agent
The liquid crystal aligning agent of the present disclosure contains a compound (P) having a partial structure (A) represented by the following formula (1).
*-Y ¹ -A ¹ -A ² -Y ² -*...(1)
(In formula (1), A ¹ and A ² are each independently a divalent group having a fused ring structure in which an aromatic ring is fused to the 2,3-position and the 4,5-position of at least one heteroaromatic ring selected from the group consisting of a pyrrole ring, a furan ring, and a thiophene ring. However, in A ¹ and A ² , at least one carbon atom of the aromatic ring constituting the fused ring structure is bonded to each other by a single bond. Y ¹ and Y ² are each independently a carbon atom, an oxygen atom, a sulfur atom, or a divalent organic group bonded to the fused ring structure in A ¹ or A ² via * ⁵ -NR ⁵ -CO-, or * ² -NR ⁴ -* ³ . R ⁴ is a hydrogen atom or a monovalent organic group, or is bonded to another group and represents a part of a ring structure formed together with the nitrogen atom to which R ⁴ is bonded. R ⁵ is a hydrogen atom or a monovalent organic group. "* ² " and "* ^"5 " represents a bond bonded to the fused ring structure in ^A1 or ^A2 . "* ³ " represents a bond bonded to -CO-. "*" represents a bond.)

In the above formula (1), with respect to the fused ring structure possessed by ^A1 and ^A2 , the heteroaromatic ring is preferably a pyrrole ring. The aromatic ring fused to the heteroaromatic ring is preferably a benzene ring or a naphthalene ring. In addition, a substituent may be introduced into the aromatic ring fused to the heteroaromatic ring. Examples of the substituent include a halogen atom, a hydroxy group, or a monovalent organic group. Among these, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the monovalent organic group include an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, an aralkyl group having 6 to 12 carbon atoms, and —NR ¹⁰ R ¹¹ (wherein R ¹⁰ and R ¹¹ are each independently a monovalent hydrocarbon group).

The fused ring structure possessed by each of A ¹ and A ² may be a carbazole ring structure, a benzocarbazole ring structure, or a dibenzocarbazole ring structure. Of these, the fused ring structure possessed by ^{A 1} and A ² is particularly preferably a carbazole ring structure.

The bonding positions of the aromatic rings constituting the fused ring structure of ^A1 and the aromatic rings constituting the fused ring structure of ^A2 are not particularly limited. For example, when the fused ring structures of each of ^A1 and ^A2 are carbazole ring structures, the bonding positions of the two carbazole rings may be the 3,3'-positions, 4,4'-positions, or 3,9'-positions, and among these, the 3,3'-positions are preferred. In ^A1 and ^A2 , the aromatic rings constituting the fused ring structure of ^A1 and the aromatic rings constituting the fused ring structure of ^A2 may be further fused.

Specific examples of the group "-A ¹ -A ² -" include groups represented by each of the following formulas (a-1) to (a-5). Of these, the group "-A ¹ -A ² -" is preferably a group represented by the following formula (a-1) or formula (a-2). Note that examples of the embodiment in which "an aromatic ring constituting the fused ring structure of A ¹ and an aromatic ring constituting the fused ring structure of A ² are further fused" include groups represented by each of the following formulas (a-3) to (a-5).
(In formulas (a-1) to (a-5), R ^a represents a halogen atom, a hydroxy group, or a monovalent organic group. ^{R b} represents a hydrogen atom or a monovalent organic group. r represents an integer of 0 to 3. E ¹ represents —O—, —S—, —NR ^c —, or —CH═CH—. R ^c represents a hydrogen atom or a monovalent organic group. When a plurality of R ^a's are present in a formula, the plurality of R ^a's are the same as or different from one another. When a plurality of E ¹ 's are present in a formula, the plurality of E ¹ 's are the same as or different from one another. "*" represents a bond.)

In the above formula (1), when Y ¹ and Y ² are * ² -NR ⁴ -* ³ , the monovalent organic group for R ⁴ is preferably an alkyl group having 1 to 5 carbon atoms or a leaving group that leaves by at least one of heat and light, and more preferably an alkyl group having 1 to 5 carbon atoms or a thermally leaving group. From the viewpoint of eliminating the group R ⁴ in the process of applying a liquid crystal alignment agent to a substrate and heating it to form a liquid crystal alignment film, thereby simplifying the process, the thermally leaving group is preferably a group that decomposes at a temperature of 120 to 300°C and is replaced by a hydrogen atom. Specifically, a tert-butoxycarbonyl group (Boc group) or a 9-fluorenylmethoxycarbonyl group is preferred, and a tert-butoxycarbonyl group is particularly preferred.

When ^R4 is bonded to another group and represents part of a ring structure formed together with the nitrogen atom to which ^R4 is bonded, a specific example of the ring structure is an imide ring structure. When ^R4 is bonded to another group and represents part of an imide ring structure formed together with the nitrogen atom, ^R4 can be represented, for example, by * ⁶ -CO-R- (R is a single bond or a divalent organic group, and * ⁶ represents a bond bonded to the nitrogen atom).

When ^Y1 and ^Y2 are divalent organic groups bonded to the fused ring structure in ^A1 or ^A2 via a carbon atom, an oxygen atom, a sulfur atom, or * ⁵ - ^NR5 -CO-, examples of the divalent organic group include divalent chain hydrocarbon groups having 1 to 20 carbon atoms, divalent alicyclic hydrocarbon groups having 4 to 20 carbon atoms, divalent aromatic hydrocarbon groups having 6 to 20 carbon atoms, divalent groups having 1 to 20 carbon atoms in which at least one methylene group in a divalent hydrocarbon group is replaced with -O-, -S-, -CO-, or * ⁵ - ^NR5 -CO-, divalent groups having 1 to 20 carbon atoms in which at least one hydrogen atom in a divalent hydrocarbon group is replaced with a substituent (for example, a halogen atom, a carboxy group, a hydroxy group, etc.), and divalent heterocyclic aromatic groups. Specific examples of when ^R5 is a monovalent organic group can be found from the explanation of ^R4 above. Examples of the heterocyclic aromatic group include a pyridinediyl group and a pyrimidinediyl group.

From the viewpoint of sufficiently reducing the afterimage (DC afterimage) caused by accumulated charge, it is preferable that the compound (P) has a partial structure (A) in its main chain. Specifically, the partial structure (A) is preferably at least one selected from the group consisting of a partial structure represented by the following formula (2) and a partial structure represented by the following formula (3):
(In formula (2), R ¹ is a halogen atom, a hydroxy group, or a monovalent organic group, or a fused ring structure formed by combining multiple R ^1s in the formula with the ring to which they are bonded. Y ³ is a divalent organic group bonded to the fused ring structure in the formula via a carbon atom. a1 is an integer of 0 to 3. When multiple R ^1s are present in the formula, the multiple R ^1s may be the same or different. Multiple Y ^3s in the formula may be the same or different. Multiple a1s in the formula may be the same or different. "*" represents a bond.)
(In formula (3), R ² is a halogen atom, a hydroxy group, or a monovalent organic group. R ³ is a hydrogen atom or a monovalent organic group. ^{Y 4} is a carbon atom, an oxygen atom, a sulfur atom, or a divalent organic group bonded to the fused ring structure in the formula via * ⁵ -NR ⁵ -CO-, or is * ² -NR ⁴ -* ³ . R ⁴ is a hydrogen atom or a monovalent organic group, or is bonded to another group to represent a part of a ring structure formed together with the nitrogen atom to which R ⁴ is bonded. R ⁵ is a hydrogen atom or a monovalent organic group. "* ² " and "* ⁵ " represent bonds bonded to the fused ring structure in the formula. "* ³ " represents a bond bonded to -CO-. a2 is an integer of 0 to 3. When there are multiple R ^2s in the formula, the multiple R ^2s may be the same or different. The multiple Y ⁴ may be the same or different from each other. Multiple a2's in the formula may be the same or different from each other. "*" represents a bond.

In the above formula (2), specific examples of the monovalent organic group for R ¹ include the groups exemplified as the substituents that may be possessed by the aromatic ring condensed to the heteroaromatic ring in the above formula (1).
When R ¹ represents a fused ring structure formed by combining multiple R ¹ in the above formula (2) together with the rings to which they are bonded, the fused ring structure includes a fused ring structure formed by combining two R ¹ bonded to the same aromatic ring together with the rings to which they are bonded, and a fused ring structure formed by combining two R ¹ bonded to different aromatic rings (for example, aromatic rings in different carbazole structures) together with the rings to which they are bonded. Specific examples of a fused ring structure formed by combining multiple R ¹ in the above formula (2) together with the rings to which they are bonded include the structures represented by each of the above formulas (a-3) to (a-5).

Specific examples of ^Y3 include the groups exemplified as the divalent organic groups for ^Y1 and ^Y2 in formula (1) above. ^Y3 is preferably a divalent organic group bonded to the fused ring structure in the formula via a carbon atom, and is more preferably a divalent hydrocarbon group having 1 to 20 carbon atoms, a divalent group having 2 to 20 carbon atoms and having -O-, -S-, -CO-, or * ⁵ - ^NR5- CO- between the carbon-carbon bonds of the divalent hydrocarbon group, a divalent group having 1 to 20 carbon atoms in which at least one hydrogen atom in the divalent hydrocarbon group has been replaced with a substituent (e.g., a halogen atom, a carboxy group, a hydroxy group, etc.), or a divalent heterocyclic aromatic group. From the viewpoints of a high residual charge reduction effect and ease of synthesis, ^Y3 is preferably a group bonded to the nitrogen atom in formula (2) above via an aromatic ring (preferably a benzene ring, a naphthalene ring, a pyridine ring, or a pyrimidine ring). a1 is preferably 0 or 1.

In the above formula (3), specific examples of ^R2 include the groups exemplified as the substituents that may be possessed by the aromatic ring fused to the heteroaromatic ring in the above formula (1).
When ^Y4 is * ² - ^NR4- * ³ , specific examples of the monovalent organic group for ^R4 include the groups exemplified as ^R4 in formula (1) above. Specific examples of when ^Y4 is a divalent organic group bonded to the fused ring structure in the formula via a carbon atom, an oxygen atom, or a sulfur atom include the divalent organic groups exemplified in the description of ^Y1 and ^Y2 . From the standpoint of a high effect of reducing residual charge and ease of synthesis, it is particularly preferred that ^Y4 be * ⁴ - ^G3 - ^A3- (wherein ^G3 is an oxygen atom or a sulfur atom, and ^A3 is a divalent aromatic ring group (preferably a group obtained by removing two hydrogen atoms from a benzene ring, a naphthalene ring, a pyridine ring, or a pyrimidine ring), and * ⁴ represents a bond bonded to the fused ring structure).

The monovalent organic group for ^R3 is preferably a monovalent hydrocarbon group having 1 to 10 carbon atoms or a leaving group that leaves due to at least one of heat and light, and more preferably an alkyl group having 1 to 5 carbon atoms, a cyclohexyl group, a phenyl group, or a thermally leaving group. Specific examples and preferred examples of ^R3 being a thermally leaving group can be found in the description of the thermally leaving group for ^R4 in formula (1) above. ^R3 is preferably a hydrogen atom or a monovalent organic group, among monovalent organic groups, in that it can further improve the transparency of the liquid crystal alignment film.
a2 is preferably 0 or 1.

Compound (P) may be a polymer component contained in the liquid crystal aligning agent, or an additive component that is blended separately from the polymer component. Compound (P) is preferably a polymer, as this allows for a more sufficient DC image retention reduction effect. Below, we will explain the polymer having partial structure (A) (hereinafter also referred to as "polymer (P)") and the additive having partial structure (A) (hereinafter also referred to as "additive (P)"), respectively.

Regarding the polymer (P), the main skeleton of the polymer (P) is not particularly limited. In terms of facilitating the introduction of the partial structure (A) into the main chain of the polymer, the polymer ( ^P ) is preferably a polymer obtained by polymerizing a monomer containing at least one diamine compound (hereinafter also referred to as a "specific diamine") selected from the group consisting of a diamine having a partial structure represented by the above formula (2) and a diamine having a partial structure represented by the above formula (3) (wherein, in the above formula (3), R4 is a hydrogen atom or a monovalent organic group). Examples of the specific diamine include polyamic acid, polyamic acid ester, polyimide, polyamide, polyurea, polyamine, polyamideimide, polyorganosiloxane, polyester, polyenamine, polybenzoxazole precursor, polybenzoxazole, cellulose derivative, polyacetal, (meth)acrylic polymer, styrene polymer, maleimide polymer, and styrene-maleimide copolymer.

In terms of the ability to form an organic film that has high affinity with liquid crystal and high mechanical strength, and the ability to obtain highly reliable liquid crystal devices, the polymer (P) is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyurea, polyorganosiloxane, and polymers containing structural units derived from a monomer having a polymerizable unsaturated carbon-carbon bond, and more preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide.

The polymer (P) may have the partial structure (A) in its main chain, in its side chain, or at its terminal. It is preferable that the polymer (P) have the partial structure (A) in its main chain, as this will result in greater improvements in film transparency, reduction of accumulated charge, and relaxation of residual charge. Furthermore, when the polymer (P) has the partial structure (A) in its main chain, the partial structure (A) may be present not only in the main chain but also in portions other than the main chain (side chains or terminals).

The method for introducing partial structure (A) into polymer (P) is not particularly limited. For example, a polymer having partial structure (A) in its main chain can be obtained by polymerizing a monomer having the partial structure represented by formula (1) in its main chain. Furthermore, a polymer having partial structure (A) in its side chain can be obtained by, for example, polymerizing a monomer having the partial structure represented by formula (1) in its side chain, or by modifying the side chain of a polymer with a reactive compound having the partial structure represented by formula (1). A polymer having partial structure (A) at the end of polymer (P) can be obtained by, for example, adding an end-capping agent (a monofunctional compound in the case of step-growth polymerization, or a polymerization initiator or polymerization terminator in the case of chain polymerization) having the partial structure represented by formula (1) and polymerizing the polymer.

When the polymer (P) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, the polymer (P) is preferably a polymer having at least one selected from the group consisting of a partial structure represented by the following formula (5) and a partial structure represented by the following formula (6):
(In formulas (5) and (6), ^X1 is a tetravalent organic group. ^X2 is a divalent organic group represented by the following formula (7) or formula (8). ^R8 , ^R9 , ^R10 , and ^R11 are each independently a hydrogen atom or a monovalent organic group having 1 to 8 carbon atoms.)
(In formula (7), ^Y5 represents a divalent organic group. Multiple ^Y5s in the formula may be the same or different. ^R1 and a1 have the same meanings as in formula (2) above. "*" represents a bond.)
(In formula (8), ^Y6 is a single bond or a divalent organic group bonded to the fused ring structure in the formula via a carbon atom, an oxygen atom, a sulfur atom, or * ⁵ - ^NR5 -CO-. ^R5 is a hydrogen atom or a monovalent organic group. "* ⁵ " represents a bond to the fused ring structure in the formula. Multiple ^Y6s in the formula are the same as or different from one another. ^R2 and a2 are defined as in formula (3) above. "*" represents a bond.)

In the above formulas (5) and (6), ^X1 is a tetravalent organic group derived from a tetracarboxylic acid derivative. In this specification, the term "tetracarboxylic acid derivative" includes tetracarboxylic acid dianhydrides, tetracarboxylic acid diesters, and tetracarboxylic acid diester dihalides.

The tetracarboxylic acid derivative constituting ^X1 can be a compound known as a tetracarboxylic acid derivative that can be used in the production of polyamic acid, polyamic acid ester, and polyimide. From the viewpoint of obtaining a liquid crystal alignment film with high transparency and with less accumulated charge, ^{X1 is preferably a tetravalent aliphatic hydrocarbon group, and specific examples include the tetravalent groups represented by each of the following formulas (11) to (16). From the above viewpoint, X1 is} preferably a tetravalent alicyclic hydrocarbon group. Furthermore, when a liquid crystal alignment film is obtained by a photoalignment method, ^X1 is preferably a tetravalent group having a cyclobutane ring structure, and specifically, a tetravalent group represented by the following formula (11) or formula (12) is particularly preferred. However, it is preferable that the polymer (P) has both a partial structure in which ^X1 is a tetravalent aliphatic hydrocarbon group and a partial structure in which ^X1 is a tetravalent aromatic hydrocarbon group, because the polarities of the accumulated charges tend to cancel each other out, resulting in a smaller accumulated charge.
(In formulas (11) to (16), "*" represents a bond.)

Regarding ^X2 , the explanation of ^Y3 in the above formula (2) can be applied to specific examples of ^Y5 in the above formula (7). The explanation of the above formula (2) can be applied to ^R1 and a1. Furthermore, the explanation of ^Y4 in the above formula (3) can be applied to specific examples of the divalent organic group of ^Y6 in the above formula (8). The explanation of the above formula (3) can be applied to ^R2 and a2 in the above formula (8).
When R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are monovalent organic groups having 1 to 8 carbon atoms, the monovalent organic groups are preferably monovalent hydrocarbon groups having 1 to 8 carbon atoms, and more preferably alkyl groups having 1 to 6 carbon atoms.

<Polyamic acid>
The synthesis method of the polymer (P) is not particularly limited, and the polymer (P) can be obtained by appropriately combining standard methods in organic chemistry. When the polymer (P) is a polyamic acid, the polyamic acid (hereinafter also referred to as "polyamic acid (P)") can be obtained, for example, by reacting a tetracarboxylic dianhydride with a diamine compound containing a specific diamine.

(Tetracarboxylic acid dianhydride)
The tetracarboxylic acid dianhydride used in the synthesis of the polyamic acid (P) is not particularly limited, and examples of the tetracarboxylic acid dianhydride include aliphatic tetracarboxylic acid dianhydrides, alicyclic tetracarboxylic acid dianhydrides, and aromatic tetracarboxylic acid dianhydrides.

Specific examples of these include aliphatic tetracarboxylic dianhydrides such as 1,2,3,4-butanetetracarboxylic dianhydride and ethylenediaminetetraacetic dianhydride;
Examples of alicyclic tetracarboxylic dianhydrides include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethylcyclobutane-1,2,3,4-tetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5, 9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornane-2:3,5:6-dianhydride, 2,4,6,8-tetracarboxybicyclo[3.3.0]octane-2:4,6:8-dianhydride, cyclohexanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, etc.;
Examples of aromatic tetracarboxylic dianhydrides include pyromellitic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, p-phenylene bis(trimellitic acid monoester anhydride), ethylene glycol bis(anhydrotrimellitate), 1,3-propylene glycol bis(anhydrotrimellitate), 3,3',4,4'-benzophenone tetracarboxylic dianhydride, and 4,4'-biphthalic dianhydride; and also include the tetracarboxylic dianhydrides described in JP-A-2010-97188.

In terms of being able to obtain a liquid crystal alignment film with high transparency and less accumulated charge when combined with a specific diamine, the tetracarboxylic acid dianhydride used in the synthesis of polyamic acid (P) preferably contains at least one selected from the group consisting of aliphatic tetracarboxylic acid dianhydrides and alicyclic tetracarboxylic acid dianhydrides (hereinafter also referred to as "specific acid anhydride"), and more preferably contains at least an alicyclic tetracarboxylic acid dianhydride. When a specific acid anhydride is used in the synthesis of polyamic acid (P), the proportion of the specific acid anhydride is preferably 30 mol% or more, more preferably 50 mol% or more, and even more preferably 70 mol% or more, based on the total amount of tetracarboxylic acid dianhydride used in the synthesis. When synthesizing polymer (P), one tetracarboxylic acid dianhydride can be used alone, or two or more tetracarboxylic acid dianhydrides can be used in combination.

When the polymer (P) is at least one selected from the group consisting of polyamic acid, polyamic acid ester, and polyimide, the polymer (P) can also be obtained by reacting a tetracarboxylic acid dianhydride containing a tetracarboxylic acid dianhydride having a partial structure represented by the above formula (1) (wherein, in the above formula (1), ^Y1 and ^Y2 may each independently be —CO—) with a diamine compound. Examples of the tetracarboxylic acid dianhydride having the partial structure represented by the above formula (1) include compounds represented by the following formulas (t-1) and (t-2). When the polymer (P) is synthesized using a tetracarboxylic acid dianhydride having a partial structure represented by the above formula (1), either the specific diamine or another diamine may be used as the diamine compound, or the specific diamine and another diamine may be used in combination.

(Diamine compound)
The specific diamine preferably has a partial structure represented by the above formula (2) or formula (3) and two primary amino groups. Preferred specific examples of the specific diamine include compounds represented by each of the following formulas (d-1) to (d-45).

Of these, the specific diamines are preferably compounds represented by the above formulas (d-1) to (d-27) and (d-34) to (d-40), and particularly preferably compounds represented by the above formulas (d-1), (d-15), (d-16), and (d-34) to (d-40). The specific diamines can be used alone or in combination of two or more.

The polymer (P) is preferably a polymer having a structural unit in which X ² in the above formula (5) and formula (6) is a divalent group represented by any one of the following formulas (x-1) to (x-4), and is particularly preferably a polymer having a structural unit in which X ¹ in the above formula (5) and formula (6) is a tetravalent aliphatic hydrocarbon group and X ² is a divalent group represented by any one of the following formulas (x-1) to (x-4).
(In formulas (x-1) to (x-4), ^G1 and ^G2 each independently represent -O- or -S-. ^Z3 and ^Z4 each independently represent -O- or -S-. ^R12 and ^R13 each independently represent a hydrogen atom or a monovalent organic group having 1 to 8 carbon atoms. "*" represents a bond.)

When synthesizing polyamic acid (P), only the specific diamine may be used as the diamine compound, but diamine compounds different from the specific diamine (hereinafter also referred to as "other diamines") may also be used together with the specific diamine.

The other diamines are not particularly limited as long as they are diamine compounds that do not have the partial structure represented by the above formula (1), and examples thereof include aliphatic diamines, alicyclic diamines, aromatic diamines, diaminoorganosiloxanes, etc. Specific examples of these include aliphatic diamines such as metaxylylenediamine, ethylenediamine, 1,3-propanediamine, tetramethylenediamine, hexamethylenediamine, etc.
Alicyclic diamines include, for example, p-cyclohexanediamine and 4,4'-methylenebis(cyclohexylamine);
Examples of aromatic diamines include dodecanoxydiaminobenzene, hexadecanoxydiaminobenzene, octadecanoxydiaminobenzene, cholestanyloxydiaminobenzene, cholesteryloxydiaminobenzene, cholestanyl diaminobenzoate, cholesteryl diaminobenzoate, lanostannyl diaminobenzoate, 3,6-bis(4-aminobenzoyloxy)cholestane, 3,6-bis(4-aminophenoxy)cholestane, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 2,5-diamino-N,N-diallylaniline, and compounds represented by the following formula (E-1):
(In formula (E-1), X ^I and X ^II each independently represent a single bond, —O—, *-COO—, or *-OCO— (wherein “*” represents a bond to X ^I ). R ^I represents an alkanediyl group having 1 to 3 carbon atoms. R ^II represents a single bond or an alkanediyl group having 1 to 3 carbon atoms. R ^III represents an alkyl group, alkoxy group, fluoroalkyl group, or fluoroalkoxy group having 1 to 20 carbon atoms. a represents 0 or 1. b represents an integer of 0 to 3. c represents an integer of 0 to 2. d represents 0 or 1, provided that 1≦a+b+c≦3.)
Side chain diamines such as compounds represented by the formula:
paraphenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-ethylenedianiline, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenyl sulfide, 4-aminophenyl-4'-aminobenzoate, 4,4'-diaminoazobenzene, 3,5-diaminobenzoic acid, 1,2-bis(4-aminophenoxy)ethane, 1,5-bis(4-aminophenoxy)pentane, N,N'-di(4-aminophenyl)-N,N'-dimethylethylenediamine, bis[2-(4-aminophenyl)ethyl]hexanedioic acid, bis(4-aminophenyl)amine, N,N-bis(4-aminophenyl)methylamine, 1,4-bis Non-side chain diamines such as (4-aminophenyl)-piperazine, N,N'-bis(4-aminophenyl)-benzidine, 2,2'-dimethylbenzidine, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4'-(phenylenediisopropylidene)bisaniline, 1,4-bis(4-aminophenoxy)benzene, 4-(4-aminophenoxycarbonyl)-1-(4-aminophenyl)piperidine, and 4,4'-[4,4'-propane-1,3-diylbis(piperidine-1,4-diyl)]dianiline;
Examples of diaminoorganosiloxanes include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, and the diamine compounds described in JP-A-2010-97188 can also be used. In synthesizing the polyamic acid (P), the other diamines can be used alone or in combination of two or more.

From the viewpoint of achieving sufficient transparency of the liquid crystal alignment film and the effect of reducing accumulated charge, the proportion of the specific diamine used is preferably 1 mol% or more, more preferably 2 mol% or more, even more preferably 5 mol% or more, and even more preferably 10 mol% or more, relative to the total amount of diamine compounds used in the synthesis of polyamic acid (P). Furthermore, from the viewpoint of ensuring the solubility of the polymer, the proportion of the specific diamine used is preferably 80 mol% or less, more preferably 70 mol% or less, relative to the total amount of diamine compounds used in the synthesis of polyamic acid (P).

Specific diamines can be obtained by appropriately combining standard organic chemistry methods. One example is a method in which a dinitro intermediate having a nitro group instead of the primary amino group in formula (5) above is synthesized, and then the nitro group of the resulting dinitro intermediate is aminated using an appropriate reduction system.

The method for synthesizing the dinitro intermediate can be selected appropriately depending on the target compound. For example, in the case of 9,9'-bis(4-aminophenyl)-3,3'-bicarbazole (the compound represented by formula (d-1) above), 3,3'-bicarbazole can be obtained by an oxidative coupling reaction of carbazole, and then 9,9'-bis(4-nitrophenyl)-3,3'-bicarbazole can be obtained as the dinitro intermediate by an aromatic nucleophilic substitution reaction between 3,3'-bicarbazole and p-fluoronitrobenzene. The nitro group of the resulting dinitro intermediate can then be reduced to obtain the target 9,9'-bis(4-aminophenyl)-3,3'-bicarbazole. Note that the synthesis method for the specific diamine is not limited to the above.

(Synthesis of Polyamic Acid)
The polyamic acid (P) can be obtained by reacting the above-mentioned tetracarboxylic dianhydride with a diamine compound, optionally together with a molecular weight modifier (also referred to as an end-capping agent). Examples of the molecular weight modifier include acid monoanhydrides, monoamine compounds, and monoisocyanate compounds. The ratio of the tetracarboxylic dianhydride and diamine compound used in the synthesis reaction of the polyamic acid (P) is preferably such that 0.2 to 2 molar equivalents of the acid anhydride groups of the tetracarboxylic dianhydride are used per 1 molar equivalent of the amino groups of the diamine compound.

The synthesis reaction of polyamic acid (P) is preferably carried out in an organic solvent. The reaction temperature is preferably -20°C to 150°C, and the reaction time is preferably 0.1 to 24 hours. Examples of organic solvents used in the reaction include aprotic polar solvents, phenolic solvents, alcohols, ketones, esters, ethers, halogenated hydrocarbons, and hydrocarbons. Particularly preferred organic solvents are one or more selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphortriamide, m-cresol, xylenol, and halogenated phenols, or mixtures of one or more of these with other organic solvents (e.g., butyl cellosolve, diethylene glycol diethyl ether, etc.). The amount of organic solvent used is preferably such that the total amount of tetracarboxylic dianhydride and diamine compound is 0.1 to 50% by mass relative to the total amount of the reaction solution. The reaction solution in which the polyamic acid (P) is dissolved may be used as is to prepare a liquid crystal aligning agent, or the polyamic acid (P) contained in the reaction solution may be isolated and then used to prepare a liquid crystal aligning agent.

<Polyamic acid ester>
The polyamic acid ester as the polymer (P) is a polymer having a structural unit in which at least one of R ⁸ and R ⁹ in the partial structure represented by the above formula (5) is a monovalent organic group having 1 to 8 carbon atoms. The polyamic acid ester can be obtained, for example, by [I] a method of reacting the polyamic acid (P) obtained above with an esterifying agent (e.g., methanol, ethanol, N,N-dimethylformamide diethyl acetal, etc.); [II] a method of reacting a tetracarboxylic acid diester with a diamine compound containing a specific diamine, preferably in an organic solvent, in the presence of a suitable dehydration catalyst (e.g., 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium halide, carbonylimidazole, a phosphorus-based condensing agent, etc.); or [III] a method of reacting a tetracarboxylic acid diester dihalide with a diamine compound containing a specific diamine, preferably in an organic solvent, in the presence of a suitable base (e.g., a tertiary amine such as pyridine or triethylamine, or an alkali metal such as sodium hydride, potassium hydride, sodium hydroxide, potassium hydroxide, sodium, or potassium).

The tetracarboxylic acid diester used in the above [II] can be obtained by ring-opening a tetracarboxylic acid dianhydride with an alcohol, etc. The tetracarboxylic acid diester dihalide used in the above [III] can be obtained by reacting the tetracarboxylic acid diester obtained as described above with a suitable chlorinating agent such as thionyl chloride.
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. When the polyamic acid ester is obtained as a solution by the above reaction, the solution may be used for preparing a liquid crystal aligning agent as it is, or the polyamic acid ester contained in the reaction solution may be isolated and then used for preparing a liquid crystal aligning agent.

<Polyimide>
The polyimide as polymer (P) is a polymer having a partial structure represented by formula (6). The polyimide can be obtained, for example, by imidizing the polyamic acid (P) synthesized as described above through dehydration and cyclization. The polyimide may be a fully imidized product in which all of the amic acid structures contained in its precursor polyamic acid (P) have been dehydrated and cyclized, or a partially imidized product in which only a portion of the amic acid structures have been dehydrated and cyclized, resulting in both amic acid structures and imide ring structures. The polyimide preferably has an imidization rate of 40 to 100%, more preferably 60 to 90%. The imidization rate is the percentage of the number of imide ring structures relative to the total number of amic acid structures and imide ring structures in the polyimide. Some of the imide rings may be isoimide rings.

The dehydration ring-closing of polyamic acid (P) is preferably carried out by dissolving the polyamic acid in an organic solvent, adding a dehydrating agent and a dehydration ring-closing catalyst to the solution, and heating as needed. Examples of dehydrating agents that can be used include acid anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride. The amount of dehydrating agent used is preferably 0.01 to 20 moles per mole of the amic acid structure of the polyamic acid. Examples of dehydration ring-closing catalysts that can be used include tertiary amines such as pyridine, collidine, lutidine, and triethylamine. The amount of dehydration ring-closing catalyst used is preferably 0.01 to 10 moles per mole of the dehydrating agent used. Examples of organic solvents that can be used include those exemplified for synthesizing polyamic acid (P). The reaction temperature for the dehydration ring-closing reaction is preferably 0 to 180°C, and the reaction time is preferably 1.0 to 120 hours. The reaction solution containing the polyimide thus obtained may be used as is to prepare a liquid crystal aligning agent, or the polyimide may be isolated and then used to prepare a liquid crystal aligning agent.

<Polyurea>
When the polymer (P) is a polyurea, the polyurea (hereinafter also referred to as "polyurea (P)") can be obtained, for example, by reacting a diisocyanate compound with a diamine compound containing a specific diamine.

(Diisocyanate compounds)
The diisocyanate compound used in the synthesis of the polyurea (P) is not particularly limited, and specific examples of the diisocyanate compound include aliphatic diisocyanates and aromatic diisocyanates.

Specific examples of these include aliphatic diisocyanates such as isophorone diisocyanate, hexamethylene diisocyanate, and tetramethylethylene diisocyanate; and aromatic diisocyanates such as o-phenylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, toluene diisocyanates (e.g., 2,4-tolylene diisocyanate), 1,4-diisocyanate-2-methoxybenzene, 2,5-diisocyanate xylenes, 2,2'-bis(4-phenyl diisocyanate)propane, 4,4'-diisocyanate diphenylmethane, 4,4'-diisocyanate diphenyl ether, 4,4'-diisocyanate diphenyl sulfone, 3,3'-diisocyanate diphenyl sulfone, and 2,2'-diisocyanate benzophenone.

The solution viscosity of polymer (P) is preferably 10 to 800 mPa·s when prepared as a 10% by weight solution, and more preferably 15 to 500 mPa·s. The solution viscosity (mPa·s) is the value measured at 25°C using an E-type rotational viscometer for a 10% by weight polymer solution prepared using a good solvent for polymer (P) (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.).

The weight-average molecular weight (Mw) of the polymer (P) measured by gel permeation chromatography (GPC) in terms of polystyrene is preferably 1,000 to 500,000, and more preferably 5,000 to 100,000. The molecular weight distribution (Mw/Mn), expressed as the ratio of Mw to the number-average molecular weight (Mn) measured by GPC in terms of polystyrene, is preferably 15 or less, and more preferably 10 or less. The liquid crystal aligning agent may contain only one type of polymer (P), or two or more types may be combined.

Regarding the additive (P), a low molecular weight compound having a functional group capable of forming a bond by heat or light together with the partial structure (A) can be preferably used as the additive (P). Here, in this specification, the term "low molecular weight compound" refers to a compound that does not have a molecular weight distribution and is a component that is distinguished from a polymer having a repeating unit. The molecular weight of the low molecular weight compound is, for example, 1500 or less, preferably 1000 or less, and more preferably 800 or less.

Preferred specific examples of the additive (P) include compounds represented by the following formula (9) or formula (10).
(In formula (9), R ¹ is a halogen atom, a hydroxy group, or a monovalent organic group, or a fused ring structure formed by combining multiple R ^1s in the formula with the rings to which they are bonded. ^{Y 5} is a divalent organic group bonded to the fused ring structure in the formula through a carbon atom. Z ¹ is a functional group capable of forming a bond by heat or light. ^{Z 2} is a hydrogen atom, a monovalent hydrocarbon group, or a functional group capable of forming a bond by heat or light. a1 is an integer of 0 to 3. When multiple R ^1s are present in the formula, the multiple R ^1s may be the same or different. Multiple Y ^5s in the formula may be the same or different. Multiple a1s in the formula may be the same or different.)
(In formula (10), ^R2 is a halogen atom, a hydroxy group, or a monovalent organic group. ^R3 is a hydrogen atom or a monovalent organic group. ^Y6 is a single bond or a divalent organic group bonded to the fused ring structure in the formula via a carbon atom, an oxygen atom, a sulfur atom, or * ⁵ - ^NR5 -CO-. ^R5 is a hydrogen atom or a monovalent organic group. * ⁵ represents a bond bonded to the fused ring structure in the formula. ^Z3 is a functional group capable of forming a bond by heat or light. ^Z4 is a hydrogen atom, a monovalent hydrocarbon group, or a functional group capable of forming a bond by heat or light. a2 is an integer of 0 to 3. When there are multiple ^R2s in the formula, the multiple ^R2s may be the same or different. Multiple ^Y6s in the formula may be the same or different. Multiple a2s in the formula may be the same or different.)

In the above formulas (9) and (10), examples of the "functional group capable of forming a bond by heat or light" include an epoxy group, an alkoxysilyl group, a silanol group, and a polymerizable unsaturated carbon-carbon bond-containing group (a vinyl group, a (meth)acryloyl group, a maleimide group, R ²⁰ OOC-CR ²¹ ═CR ²² -CONR ²³ -* (wherein R ²⁰ to R ²³ are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms)). Of these, a polymerizable unsaturated carbon-carbon bond-containing group is preferred because of its high reactivity to heat or light.

When the groups represented by ^Z2 and ^Zd are monovalent hydrocarbon groups, examples of the hydrocarbon group include chain hydrocarbon groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups, etc. In terms of enhancing the effect of reducing DC afterimage, ^Z2 and ^Z4 are preferably functional groups capable of forming a bond by heat or light, and more preferably polymerizable unsaturated carbon-carbon bond-containing groups.

Specific examples of the additive (P) include compounds represented by the following formulas (a-1) to (a-5).

<Other ingredients>
The liquid crystal aligning agent of the present disclosure may further contain components other than the compound (P) (hereinafter also referred to as "other components"). Examples of other components include polymers that do not have the partial structure (A) represented by the above formula (1) (hereinafter also referred to as "other polymers"), compounds having one or more epoxy groups in the molecule, functional silane compounds, compounds having one or more (meth)acryloyl groups in the molecule, antioxidants, metal chelate compounds, curing accelerators, surfactants, fillers, dispersants, photosensitizers, acid generators, base generators, radical generators, etc. The blending ratios of these can be appropriately selected depending on each compound, as long as they do not impair the effects of the present disclosure.

<Other polymers>
The main skeleton of the other polymer is not particularly limited, but examples include polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, polyester, polyenamine, polyurea, polyamide, polyamideimide, polybenzoxazole precursor, polybenzoxazole, cellulose derivative, polyacetal, (meth)acrylic polymer, styrene polymer, maleimide polymer, styrene-maleimide copolymer, etc. From the viewpoint of obtaining a highly reliable liquid crystal device, the other polymer is preferably at least one selected from the group consisting of polyamic acid, polyamic acid ester, polyimide, polyorganosiloxane, and polymers containing a structural unit derived from a monomer having a polymerizable unsaturated carbon-carbon bond. Examples of polymers containing a structural unit derived from a monomer having a polymerizable unsaturated carbon-carbon bond include (meth)acrylic polymers, styrene polymers, maleimide polymers, and styrene-maleimide copolymers. As the other polymer, one type may be used alone, or two or more types may be used in combination.

When compound (P) is a polymer and another polymer is contained in the liquid crystal aligning agent together with polymer (P), the content of the other polymer is preferably 1% by mass or more, and more preferably 2% by mass or more, based on the total amount of polymer (P) and the other polymer. Furthermore, the content of the other polymer is preferably 95% by mass or less, and more preferably 90% by mass or less, based on the total amount of polymer (P) and the other polymer.

When compound (P) is an additive component, the liquid crystal aligning agent of the present disclosure contains a polymer component together with additive (P). When the polymer component is another polymer, the content of the other polymer is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, relative to the total amount of solid components of the liquid crystal aligning agent (i.e., components other than the solvent contained in the liquid crystal aligning agent). Furthermore, the content of the other polymer is preferably 99% by mass or less, more preferably 98% by mass or less, and even more preferably 95% by mass or less, relative to the total amount of solid components of the liquid crystal aligning agent.

<Solvent>
The liquid crystal aligning agent of the present disclosure is preferably prepared as a liquid composition in which the compound (P) and other components used as needed are dispersed or dissolved in a suitable solvent.

Examples of organic solvents that can be used include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolidinone, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone (diacetone alcohol), ethylene glycol monomethyl ether, butyl lactate, butyl acetate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, and ethylene glycol-i-propyl ether. Examples of suitable ethers include 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, ethylene carbonate, and propylene carbonate. These may be used alone or in combination of two or more.

The solids concentration in the liquid crystal aligning agent (the proportion of the total mass of the liquid crystal aligning agent's components other than the solvent to the total mass of the liquid crystal aligning agent) is selected appropriately taking into consideration viscosity, volatility, etc., but is preferably in the range of 1 to 10% by mass. That is, the liquid crystal aligning agent is applied to the substrate surface as described below, and preferably heated to form a coating film that is a liquid crystal alignment film or a coating film that will become a liquid crystal alignment film. In this case, a solids concentration of 1% by mass or more is preferable because it ensures a sufficient coating film thickness and makes it easier to obtain a good liquid crystal alignment film. Furthermore, a solids concentration of 10% by mass or less ensures that the coating film does not become too thick, allowing a good liquid crystal alignment film to be obtained, and also ensures appropriate viscosity of the liquid crystal aligning agent, improving coatability.

When compound (P) is a polymer, the content of compound (P) in the liquid crystal aligning agent is preferably 2 parts by mass or more, and more preferably 5 parts by mass or more, per 100 parts by mass of the total solid components (components other than the solvent) in the liquid crystal aligning agent, from the viewpoint of fully obtaining the effects of incorporating polymer (P). When compound (P) is an additive, the content of additive (P) is preferably 1 part by mass or more, and more preferably 2 parts by mass or more, per 100 parts by mass of the total solid components in the liquid crystal aligning agent. Furthermore, from the viewpoint of ensuring the liquid crystal alignment properties and electrical properties of the liquid crystal alignment film, the content of additive (P) is preferably 30 parts by mass or less, and more preferably 25 parts by mass or less, per 100 parts by mass of the total solid components in the liquid crystal aligning agent.

<Liquid crystal alignment film and liquid crystal element>
The liquid crystal alignment film of the present disclosure is formed using the liquid crystal alignment agent prepared as described above. Furthermore, the liquid crystal element of the present disclosure includes a liquid crystal alignment film formed using the liquid crystal alignment agent described above. The operation mode of the liquid crystal in the liquid crystal element is not particularly limited, and various modes can be applied, such as TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, VA (Vertical Alignment) type (including VA-MVA type, VA-PVA type, etc.), IPS (In-Plane Switching) type, FFS (Fringe Field Switching) type, and OCB (Optically Compensated Bend) type. The liquid crystal element can be manufactured, for example, by a method including the following steps 1 to 3. In step 1, the substrate used varies depending on the desired operation mode. Steps 2 and 3 are common to all operation modes.

(Step 1: Formation of coating film)
First, a liquid crystal alignment agent is applied to a substrate, and the coated surface is preferably heated to form a coating film on the substrate. Examples of substrates that can be used include glass, such as float glass and soda glass; and transparent substrates made of plastics, such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly(alicyclic olefin). Examples of transparent conductive films that can be provided on one side of the substrate include 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 ). When manufacturing TN-type, STN-type, VA-type, or PSA-type liquid crystal devices, two substrates each having a patterned transparent conductive film are used. On the other hand, when manufacturing IPS-type or FFS-type liquid crystal devices, a substrate having an electrode made of a comb-shaped patterned transparent conductive film or metal film and an opposing substrate without an electrode are used. Examples of metal films that can be used include a film made of a metal, such as chromium. The liquid crystal alignment agent is applied to the substrate on the electrode-forming surface, preferably by offset printing, spin coating, roll coating, or inkjet printing.

After applying the liquid crystal alignment agent, preheating (pre-baking) is preferably performed to prevent dripping of the applied liquid crystal alignment agent. The pre-baking temperature is preferably 30 to 200°C, and the pre-baking time is preferably 0.25 to 10 minutes. The solvent is then completely removed, and if necessary, a baking (post-baking) step is performed to thermally imidize the amic acid structure present in the polymer. The baking temperature (post-baking temperature) is preferably 80 to 300°C, and the post-baking time is preferably 5 to 200 minutes. The thickness of the film formed in this manner is preferably 0.001 to 1 μm. After applying the liquid crystal alignment agent to the substrate, the organic solvent is removed to form a liquid crystal alignment film, or a coating film that will become a liquid crystal alignment film.

(Step 2: Alignment Treatment)
When producing a TN-type, STN-type, IPS-type, or FFS-type liquid crystal element, the coating film formed in step 1 above is subjected to a treatment (alignment treatment) to impart liquid crystal alignment ability. This imparts the alignment ability of liquid crystal molecules to the coating film, turning it into a liquid crystal alignment film. As the alignment treatment, a rubbing treatment in which the surface of the coating film formed on the substrate is rubbed with cotton or the like, or a photo-alignment treatment in which the coating film is irradiated with light to impart liquid crystal alignment ability, is preferably used. When producing a vertical alignment type liquid crystal element, the coating film formed in step 1 above may be used as a liquid crystal alignment film as is, or the coating film may be subjected to an alignment treatment to further enhance the liquid crystal alignment ability.

Light irradiation in the photo-alignment treatment can be performed by irradiating the coating film after the post-bake step, irradiating the coating film after the pre-bake step but before the post-bake step, or irradiating the coating film while it is being heated in at least one of the pre-bake and post-bake steps. 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. Preferably, ultraviolet light containing light with a wavelength of 200 to 400 nm is used. When the radiation is polarized, it may be linearly polarized or partially polarized. Furthermore, when the radiation used is linearly polarized or partially polarized, irradiation may be performed perpendicular to the substrate surface, obliquely, or in a combination of these directions. When irradiating with unpolarized radiation, the irradiation direction is oblique.

Examples of light sources that can be used include low-pressure mercury lamps, high-pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonance lamps, xenon lamps, and excimer lasers. The radiation dose is preferably 400 to 20,000 J/ ^m2 , and more preferably 1,000 to 5,000 J/ ^m2 . The coating film may be irradiated with light while being heated in order to enhance its reactivity.

When producing a liquid crystal alignment film, the coating film that has been subjected to light irradiation treatment may be heated at a temperature range of 120°C or higher and 280°C or lower. This type of heat treatment is preferable because it further improves the liquid crystal alignment (thermal realignment) and allows for the production of liquid crystal elements with reduced AC afterimages. This heating may be post-baking, or it may be a heat treatment performed separately from post-baking and after post-baking. The heating temperature is preferably 140°C or higher, and more preferably 150°C to 250°C, from the perspective of promoting molecular chain realignment by heating. The heating time is preferably 5 to 200 minutes, more preferably 10 to 60 minutes.

The production of a liquid crystal alignment film may further include a contacting step in which the light-irradiated coating film is brought into contact with water, a water-soluble organic solvent, or a mixed solvent of water and a water-soluble organic solvent. Examples of water-soluble organic solvents include methanol, ethanol, 1-propanol, isopropanol, 1-methoxy-2-propanol acetate, butyl cellosolve, ethyl lactate, acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclopentanone. Methods for contacting the coating film with the solvent include, but are not limited to, spraying, showering, immersion, and puddling. The contact time between the coating film and the solvent is not particularly limited, but is, for example, 5 seconds to 15 minutes. The coating film may be heat-treated after the contacting step.

(Step 3: Construction of liquid crystal cell)
Two substrates each having a liquid crystal alignment film formed thereon are prepared as described above, and a liquid crystal cell is fabricated by disposing a liquid crystal between the two substrates. Examples of methods for fabricating a liquid crystal cell include: (1) arranging the two substrates facing each other with a gap (spacer) between them so that the liquid crystal alignment films face each other, bonding the peripheries of the two substrates together using a sealant, injecting liquid crystal into the substrate surfaces and the cell gap defined by the sealant, and then sealing the injection hole; and (2) applying a sealant to a predetermined location on one of the substrates on which the liquid crystal alignment film is formed, dropping liquid crystal onto several predetermined locations on the liquid crystal alignment film surface, and then bonding the other substrate so that the liquid crystal alignment film faces the other substrate, and spreading the liquid crystal over the entire surface of the substrate (ODF method). It is desirable to further heat the fabricated liquid crystal cell to a temperature at which the liquid crystal used assumes an isotropic phase, and then slowly cool it to room temperature to remove flow alignment during liquid crystal filling.

The sealing agent can be, for example, an epoxy resin containing a curing agent and aluminum oxide spheres as spacers. The spacers can be photospacers, bead spacers, etc.

Either positive-type or negative-type liquid crystals may be used. The use of negative-type liquid crystals in IPS-type and FFS-type liquid crystal elements is preferable because it reduces transmission loss above the electrodes and improves contrast. Examples of liquid crystals include nematic liquid crystals and smectic liquid crystals, with nematic liquid crystals being preferred. Examples of nematic liquid crystals that can be used include Schiff-base liquid crystals, azoxy liquid crystals, biphenyl-based liquid crystals, phenylcyclohexane-based liquid crystals, ester-based liquid crystals, terphenyl-based liquid crystals, biphenylcyclohexane-based liquid crystals, pyrimidine-based liquid crystals, dioxane-based liquid crystals, bicyclooctane-based liquid crystals, and cubane-based liquid crystals. These liquid crystals may also be used with the addition of, for example, cholesteric liquid crystals, chiral agents, or ferroelectric liquid crystals.

In PSA mode, a polymerizable compound (e.g., a polyfunctional (meth)acrylate compound) is filled into the cell gap along with liquid crystal to form a liquid crystal cell, and then the liquid crystal cell is irradiated with light while a voltage is applied between the conductive films of a pair of substrates. When manufacturing PSA-type liquid crystal elements, the polymerizable compound is used in an amount of, for example, 0.01 to 3 parts by weight, preferably 0.1 to 1 part by weight, per 100 parts by weight of liquid crystal.

Next, if necessary, a polarizing plate is attached to the outer surface of the liquid crystal cell. Examples of polarizing plates include a polarizing film called an "H film" made by stretching and aligning polyvinyl alcohol and absorbing iodine, sandwiched between cellulose acetate protective films, or a polarizing plate made of the H film itself. This completes the liquid crystal device.

The liquid crystal element of the present disclosure can be effectively applied to a variety of applications, including 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, and information displays, as well as light control films. Furthermore, liquid crystal elements formed using the liquid crystal alignment agent of the present disclosure can also be used in optical films such as retardation films.

The following provides a more detailed explanation using examples, but the present invention is not limited to these examples.

<Compound structures and abbreviations>
The structures and abbreviations of the main compounds used in the following examples are as follows:
[Tetracarboxylic acid dianhydride]
TA-1: 1,2,3,4-cyclobutanetetracarboxylic dianhydride TA-2: (1R,2R,3S,4S)-1,3-dimethylcyclobutane-1,2,3,4-tetracarboxylic dianhydride TA-3: 2,3,5-tricarboxycyclopentylacetic dianhydride TA-4: Pyromellitic dianhydride TA-5: 4,4'-biphthalic dianhydride

[Diamine]
DA-1; 9,9'-bis(4-aminophenyl)-3,3'-bicarbazole DA-2; 9,9'-bis(4-(4-aminophenoxy)phenyl)-3,3'-bicarbazole DA-3; 9,9'-diethyl-6,6'-bis(4-aminophenoxy)-3,3'-bicarbazole DA-4; 9,9'-diethyl-3,3'-bicarbazole-6,6'-diamine DA-5; 4,4'-diaminodiphenylamine DA-6; 3,6-diaminocarbazole DA-7; 4,4'-diaminotriphenylamine DA-8; N4,N4'-bis(4-aminophenyl)-N4,N4'-dimethylbenzidine DA-9; 4,4'-diaminodiphenylamine Phenylmethane DA-10; 3,5-Diaminobenzoic Acid DA-11; 4,4'-Bis(4-aminophenoxy)biphenyl DA-12; 2,2-Bis(4-(4-aminophenoxy)phenyl)propane DA-13; 2,2'-Dimethylbenzidine DA-14; 5(6)-Amino-1,3,3-trimethyl-1-(4-aminophenyl)indane DA-15; N,N'-Bis(5-aminopyridin-2-yl)-N,N'-di(tert-butoxycarbonyl)ethylenediamine DA-16; N1,N6-Bis(4-aminophenethyl)-N1,N6-di(tert-butoxycarbonyl)adipamide DA-17; 5ξ-Cholestan-3-yl 2,4-diaminophenyl ether

[solvent]
NMP; N-methyl-2-pyrrolidone NEP; N-ethyl-2-pyrrolidone GBL; γ-butyrolactone BC; butyl cellosolve DAA; diacetone alcohol DEDG: diethylene glycol diethyl ether

[Additives]
AD-1: N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane AD-2: 3-glycidyloxypropyltriethoxysilane AD-3: dipentaerythritol hexaacrylate AD-4: 2,4,6,8-tetramethyl-2,4,6,8-tetrakis(3-glycidyloxypropyl)-1,3,5,7,2,4,6,8-tetraoxatetrasilocane AD-5: a compound represented by the following formula (AD-5)

<Synthesis of Compounds>
[Synthesis Example 1]
3,3'-bicarbazole (3.0 mmol), p-fluoronitrobenzene (7.5 mmol), potassium carbonate (12 mmol), and NMP (20 mL) were placed in a three-neck flask equipped with a nitrogen inlet tube and stirred under nitrogen at 160°C for 6 hours. After completion of the reaction, the reaction solution was poured into water to precipitate the product. The resulting precipitate was washed with water and ethyl acetate and dried in vacuo to obtain a yellowish-brown solid compound represented by the following formula (DA-1-1) in a yield of 90%.
Compound (DA-1-1) (2.0 mmol), 5% Pd/C (0.23 g), hydrazine monohydrate (1.15 g), and NMP (20 mL) were placed in a three-neck flask equipped with a nitrogen inlet tube and stirred at 80°C under nitrogen for 6 hours. After completion of the reaction, the reaction solution was filtered through Celite, ethyl acetate was added, and the mixture was separated and washed with water. The organic phase was concentrated under reduced pressure to obtain 9,9'-bis(4-aminophenyl)-3,3'-bicarbazole (the diamine represented by the above formula (DA-1)) as a brown solid in 80% yield. ^{The 1H} -NMR spectrum (DMSO- _d6 , 400 MHz) and ^13C -NMR spectrum (DMSO- _d6 , 75 MHz) of diamine (DA-1) are shown in Figures 1 and 2, respectively.

[Synthesis Example 2]
According to the following reaction scheme, in the same manner as in Synthesis Example 1, 9,9'-bis(4-(4-aminophenoxy)phenyl)-3,3'-bicarbazole (diamine represented by the above formula (DA-2)) was obtained.

[Synthesis Example 3]
According to the following reaction scheme, 9,9'-diethyl-6,6'-bis(4-aminophenoxy)-3,3'-bicarbazole (diamine represented by the above formula (DA-3)) was obtained in the same manner as in Synthesis Example 1. The compound represented by the following formula (DA-3-1) was synthesized according to a known literature (Journal of Photochemistry and Photobiology A: Chemistry (2004), 162, 187-191).

[Synthesis Example 4]
According to the following reaction scheme, 9,9'-diethyl-3,3'-bicarbazole-6,6'-diamine (diamine represented by the above formula (DA-4)) was obtained in the same manner as in Synthesis Example 1. The compound represented by the following formula (DA-4-1) was synthesized according to a known literature (Journal of Organic Chemistry (2019), 84, 73-93).

<Synthesis and Evaluation of Polymer>
Polymers were synthesized in the following Synthesis Examples 5 to 25. In the following examples, the weight-average molecular weight _Mw and number-average molecular weight _Mn of the polymer, the imidization rate of polyimide in the polymer solution, the solution viscosity of the polymer solution, and the epoxy equivalent were measured by the following methods.
[Weight average molecular weight _Mw and number average molecular weight _Mn ]
In Synthesis Examples 24 and 25, _Mw and _Mn are values calculated as polystyrene measured by GPC under the following conditions.
Column: TSKgel GRCXLII, manufactured by Tosoh Corporation
Solvent: tetrahydrofuran Temperature: 40°C
Pressure: 68 kgf/ ^cm2

[Imidization rate of polyimide]
The polyimide solution was poured into pure water, and the resulting precipitate was thoroughly dried under reduced pressure at room temperature. The precipitate was then dissolved in deuterated dimethyl sulfoxide and subjected to ^1H -NMR measurement at room temperature using tetramethylsilane as a reference material. The imidization rate [%] was calculated from the obtained ^1H -NMR spectrum (400 MHz) using the following formula (1):
Imidization rate [%] = (1 - (A ₁ / (A ₂ × α))) × 100 (1)
(In formula (1), _A1 is the peak area derived from the protons of the amide group appearing at a chemical shift of approximately 10 ppm, _A2 is the peak area derived from the protons of the aromatic group appearing at a chemical shift of approximately 6 to 9 ppm, and α is the ratio of the number of protons of the aromatic group to one proton of the amide group in the polymer precursor (polyamic acid).)
[Solution viscosity of polymer solution]
The solution viscosity (mPa·s) of the polymer solution was measured at 25° C. using an E-type rotational viscometer.
[Epoxy equivalent]
The epoxy equivalent was measured by the hydrochloric acid-methyl ethyl ketone method described in JIS C 2105.

[Synthesis Example 5]
Diamines (20 parts by mole of diamine (DA-1) and 80 parts by mole of diamine (DA-9)) were dissolved in NMP, and 0.95 molar equivalents of tetracarboxylic dianhydride (TA-1) relative to the total amount of diamines was added thereto. The mixture was allowed to react at room temperature for 6 hours, thereby obtaining a 15% by mass solution of polyamic acid (PI-1) having a partial structure represented by the following formula (PI-1):

[Synthesis Examples 6 to 22]
Polyamic acids (PI-2 to PI-18) were obtained in the same manner as in Synthesis Example 5, except that the types and molar ratios of the tetracarboxylic dianhydrides and diamines were changed as shown in Table 1. Note that the values in Table 1 indicate the proportion (mol %) of each compound used relative to the total amount (100 mol %) of the acid dianhydrides used in the synthesis, and the values in Table 1 indicate the proportion (mol %) of each compound used relative to the total amount (100 mol %) of the diamines used in the synthesis.

[Synthesis Example 23]
Diamines (50 molar parts of diamine (DA-15) and 50 molar parts of diamine (DA-13)) were dissolved in NMP, and 0.95 molar equivalents of tetracarboxylic dianhydride (TA-2) based on the total amount of diamines was added. The reaction was carried out at room temperature for 6 hours to obtain a solution of polyamic acid. To the obtained solution, 0.80 molar equivalents of 1-methylpiperidine and acetic anhydride based on the carboxy groups of the polyamic acid were added as dehydrating agents, and the mixture was heated and stirred at 60°C for 3 hours. The obtained solution was repeatedly concentrated under reduced pressure and diluted with NMP to obtain a 10 mass% solution of polyimide (PI-19) having a partial structure represented by the following formula (PI-19). The imidization rate of polyimide (PI-19) was 78%.

[Synthesis Example 24]
A reaction vessel equipped with a stirrer, thermometer, dropping funnel, and reflux condenser was charged with 100.0 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (a compound represented by the following formula (S-1)), 500 g of methyl isobutyl ketone, and 10.0 g of triethylamine, and mixed at room temperature. Next, 100 g of deionized water was added dropwise from the dropping funnel over 30 minutes, and the mixture was stirred under reflux at 80 ° C. for 6 hours. After completion of the reaction, the organic layer was removed and washed with a 0.2% by mass aqueous ammonium nitrate solution until the water after washing became neutral. The solvent and water were then distilled off under reduced pressure to obtain an epoxy group-containing polyorganosiloxane (ESSQ-1) as a viscous, transparent liquid. When polyorganosiloxane (ESSQ-1) was analyzed by ^1H -NMR, a peak due to the epoxy group was observed at a chemical shift (δ) of approximately 3.2 ppm, confirming that no side reactions of the epoxy group occurred during the reaction. The weight-average molecular weight _Mw of the resulting polyorganosiloxane (ESSQ-1) was 3,500, and the epoxy equivalent was 180 g/mol.
In a 200 mL three-necked flask, 10.0 g of polyorganosiloxane (ESSQ-1), 30.28 g of methyl isobutyl ketone as a solvent, a compound represented by the following formula (S-2) as a modified component (carboxylic acid) and a compound represented by the following formula (S-3), the total amount of epoxy groups in the polyorganosiloxane (ESSQ-1), amounts equivalent to 20 mol% and 10 mol%, respectively, and 0.10 g of UCAT 18X (trade name, manufactured by San-Apro Co., Ltd.) as a catalyst were charged and the reaction was carried out under stirring at 100 ° C. for 48 hours. After completion of the reaction, ethyl acetate was added to the reaction mixture and the resulting solution was washed three times with water, the organic layer was dried using magnesium sulfate, and the solvent was then distilled off to obtain a polyorganosiloxane (PSQ-1) containing an orienting group. The weight average molecular weight M _w of the resulting polymer was 8000.

[Synthesis Example 25]
Under nitrogen, 6.38 g of a compound represented by the following formula (M-1), 1.90 g of 4-(glycidyloxymethyl)styrene (a compound represented by the following formula (M-2)), and 0.86 g of methacrylic acid were added as polymerization monomers to a 100 mL two-neck flask, 0.46 g of 2,2'-azobis(2,4-dimethylvaleronitrile) as a radical polymerization initiator, and 40 ml of N-methyl-2-pyrrolidone (NMP) as a solvent, and polymerization was carried out at 70°C for 6 hours. After reprecipitation in methanol, the precipitate was filtered and dried in vacuum at room temperature for 8 hours to obtain the target polymer (PMI-1). The weight average molecular weight _Mw measured in polystyrene equivalent terms by GPC was 30,000, and the molecular weight distribution _Mw / _Mn was 2.

<Preparation and Evaluation of Liquid Crystal Alignment Agent>
[Example 1: Photo-aligned FFS-type liquid crystal display element]
(1) Preparation of liquid crystal aligning agent Polymer components (solid content equivalent: 80 parts by mass of polymer (PI-1) and 20 parts by mass of polymer (PI-19)) were diluted with NMP, GBL, and BC to obtain a solution with a solid content concentration of 4.0% by mass and a solvent composition ratio of NMP:GBL:BC = 50:25:25 (mass ratio). This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal aligning agent (AL-1).

(2) Evaluation of Optical Properties (Transparency) The liquid crystal alignment agent (AL-1) prepared in (1) above was applied to a quartz substrate using a spin coater, heated on a hot plate at 80 ° C for 1 minute, and then heated in an oven at 230 ° C with nitrogen purging for 30 minutes to form a coating film with an average thickness of 100 nm. For the quartz substrate on which this coating film was formed, an ultraviolet-visible-near-infrared spectrophotometer (manufactured by JASCO Corporation, product name "V-670") was used to measure the absorption spectrum in the ultraviolet and visible light region, using a quartz substrate of the same type without a coating film as a reference. Note that the influence of reflection was suppressed by using P-polarized light with a polarizing filter and setting the angle of incidence on the substrate to the Brewster angle. A transmittance of 98% or more at a wavelength of 400 nm was rated "good," and a transmittance of less than 98% was rated "poor." As a result, this example was rated "good."

(3) Formation of a liquid crystal alignment film by photo-alignment method A glass substrate having a flat electrode, an insulating layer, and a comb-shaped electrode laminated in this order on one side, and an opposing glass substrate having no electrodes, were coated with the liquid crystal alignment agent (AL-1) prepared in (1) above using a spin coater, heated on a hot plate at 80 ° C for 1 minute, and then heated for 30 minutes in a 230 ° C oven with the interior of the oven substituted with nitrogen, to form a coating film with an average film thickness of 100 nm. This coating film surface was subjected to a photo-alignment treatment by irradiating 300 mJ / cm ² of linearly polarized ultraviolet light containing a 254 nm emission line from the substrate normal direction using an Hg-Xe lamp. The coating film subjected to this photo-alignment treatment was then heat-treated for 30 minutes in a 230 ° C oven with the interior of the oven substituted with nitrogen, to form a liquid crystal alignment film.

(4) Fabrication of FFS-Mode Liquid Crystal Display Element: An epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was dispensed onto the outer periphery of the surface bearing the liquid crystal alignment film of one of the substrates prepared in (3), leaving a liquid crystal injection port. The pair of substrates were then placed face-to-face with their liquid crystal alignment film-bearing surfaces facing each other and pressed together so that the alignment treatment directions of each substrate were antiparallel. The adhesive was then thermally cured at 150°C for 1 hour. Next, negative nematic liquid crystal (Merck, MJ20195NCMP) was filled into the gap between the substrates through the liquid crystal injection port, which was then sealed with an epoxy adhesive. The substrates were then heated to 120°C and slowly cooled to room temperature to eliminate flow alignment during liquid crystal injection. Next, polarizers were attached to both outer surfaces of the substrates so that their polarization directions were perpendicular to each other and at a 45° angle with the alignment treatment direction of the liquid crystal alignment film, thereby fabricating an FFS-mode liquid crystal display element.

(5) Evaluation of DC Image Retention Characteristics The liquid crystal display device manufactured in (4) above was placed in an environment of 25°C and 1 atmosphere. After driving the device at intermediate tones with a 30 Hz square wave (AC) to set the luminance difference between any two pixels to zero, a direct current (DC) of 1 V was applied to only one of the pixels for 30 minutes while driving with AC to accumulate charge. When the application of DC 1 V was terminated and the device was returned to AC-only operation, a luminance difference ΔL occurred between the two pixels due to the accumulated charge. The change in this luminance difference ΔL over time was observed, and the time from the end of application of DC 1 V until the luminance difference ΔL divided by the average luminance of the two pixels fell to 2% or less was defined as the image retention time. The shorter this time, the less likely image retention caused by the application of DC voltage. An image retention time of less than 10 minutes was rated "excellent," a time of 10 to 20 minutes was rated "good," and a time of 20 minutes or more was rated "poor." As a result, this example was rated "excellent."

[Examples 2 to 12, Comparative Examples 1 to 4]
In the same manner as in Example 1, except that the components contained in the liquid crystal alignment agent in Example 1 were changed as shown in the following Table 2, a liquid crystal alignment agent was prepared, a liquid crystal alignment film was formed by a photoalignment method, and an FFS-type liquid crystal display element was manufactured and various evaluations were performed. The evaluation results are shown in Table 2 below.

[Example 13: Rubbed Alignment FFS-Type Liquid Crystal Display Element]
(1) Preparation of liquid crystal aligning agent Polymer components (solid content equivalent: 70 parts by mass of polymer (PI-1) and 30 parts by mass of polymer (PI-18)) were diluted with NMP, GBL, DAA, and BC to obtain a solution with a solid content concentration of 4.0% by mass and a solvent composition ratio of NMP:GBL:DAA:BC = 30:30:30:10 (mass ratio). This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal aligning agent (AL-17).

(2) Evaluation of Optical Properties (Transparency) The liquid crystal aligning agent (AL-17) prepared in (1) above was evaluated for transparency in the same manner as in Example 1. As a result, in this example, the evaluation was "good".
(3) Formation of a liquid crystal alignment film by rubbing method A glass substrate having a flat electrode, an insulating layer, and a comb-shaped electrode laminated in this order on one side thereof, and a counter glass substrate having no electrode, were coated with the liquid crystal alignment agent (AL-17) prepared in (1) above using a spin coater, heated on a hot plate at 80 ° C. for 1 minute, and then heated in an oven at 230 ° C. with the interior of the oven substituted with nitrogen for 30 minutes to form a coating film with an average film thickness of 100 nm. This coating film surface was subjected to rubbing treatment twice using a rubbing machine having a roll wrapped around a nylon cloth, at a roll rotation speed of 1000 rpm, a stage movement speed of 30 mm / sec, and a pile indentation length of 0.3 mm. The coating film subjected to this rubbing alignment treatment was ultrasonically cleaned in ultrapure water for 1 minute, and then dried in an oven at 100 ° C. for 10 minutes to form a liquid crystal alignment film.
(4) Production of FFS-Type Liquid Crystal Display Element An FFS-type liquid crystal display element was produced in the same manner as in Example 1 using a pair of substrates having the liquid crystal alignment film produced in (3) above.
(5) Evaluation of DC Afterimage Characteristics The DC afterimage characteristics of the FFS-type liquid crystal display element manufactured in (4) above were evaluated in the same manner as in Example 1. As a result, the evaluation of this example was "excellent."

[Examples 14 to 15 and Comparative Examples 5 to 6]
In the same manner as in Example 13, except that the components contained in the liquid crystal alignment agent in Example 13 were changed as shown in the following Table 2, a liquid crystal alignment agent was prepared, a liquid crystal alignment film was formed by a rubbing method, and an FFS-type liquid crystal display element was manufactured and various evaluations were performed. The evaluation results are shown in Table 2 below.

[Example 16: PSA type liquid crystal display element]
(1) Preparation of liquid crystal aligning agent Polymer components (solid content equivalent: polymer (PI-13) 95 parts by mass and polymer (PSQ-1) 5 parts by mass) were diluted with NMP and BC to obtain a solution with a solid content concentration of 4.0 mass% and a solvent composition ratio of NMP:BC = 50:50 (mass ratio). This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal aligning agent (AL-22).

(2) Preparation of Liquid Crystal Composition 5% by mass of a liquid crystal compound represented by the following formula (L-1) and 0.3% by mass of a photopolymerizable compound represented by the following formula (L-2) were added to 10 g of a nematic liquid crystal (MLC-6608, manufactured by Merck) and mixed to obtain a liquid crystal composition (LC-1).

(3) Evaluation of Optical Properties (Transparency) The liquid crystal aligning agent (AL-22) prepared in (1) above was evaluated for transparency in the same manner as in Example 1. As a result, in this example, the evaluation was "good".
(4) Formation of Liquid Crystal Alignment Film The liquid crystal alignment agent (AL-22) prepared in (1) above was applied to each electrode surface of two glass substrates having slit-shaped patterned ITO electrodes using a spin coater, heated on a hot plate at 80°C for 1 minute, and then heated in an oven at 230°C with the interior substituted with nitrogen for 30 minutes to form a coating film with an average film thickness of 100 nm. This coating film was ultrasonically cleaned in ultrapure water for 1 minute and then dried in an oven at 100°C for 10 minutes to form a liquid crystal alignment film. The electrode pattern used was the same type of pattern as the electrode pattern in the PSA mode.

(5) Production of PSA-type liquid crystal display element An epoxy resin adhesive containing aluminum oxide spheres with a diameter of 3.5 μm was dispensed onto the outer periphery of the surface having the liquid crystal alignment film of one of the substrates prepared in (4) above, leaving a liquid crystal injection port, and then the pair of substrates were overlapped with the surfaces having the liquid crystal alignment films facing each other and pressed together, and the adhesive was thermally cured for 1 hour at 150° C. Next, the liquid crystal composition (LC-1) prepared in (2) above was filled into the gap between the substrates through the liquid crystal injection port, and the liquid crystal injection port was sealed with an epoxy-based adhesive to produce a liquid crystal cell.
The resulting liquid crystal cell was irradiated with ultraviolet light at a dose of 10,000 mJ/ ^cm² using an ultraviolet irradiation device with a metal halide lamp as a light source while the liquid crystal was in operation. This dose was measured using an actinometer measuring at a wavelength of 365 nm. Next, polarizing plates were attached to both outer surfaces of the substrate so that their polarization directions were perpendicular to each other and at a 45° angle with the alignment treatment direction of the liquid crystal alignment film, thereby producing a PSA-type liquid crystal display element.
(6) Evaluation of DC Afterimage Characteristics The liquid crystal display element manufactured in (5) above was evaluated for DC afterimage characteristics in the same manner as in Example 1. As a result, the liquid crystal display element in this example was evaluated as "excellent."

[Example 17]
In the same manner as in Example 16, except that the components contained in the liquid crystal alignment agent were changed as shown in the following Table 2, a liquid crystal alignment agent was prepared, a liquid crystal alignment film was formed, and a PSA type liquid crystal display element was manufactured and various evaluations were performed. The evaluation results are shown in Table 2 below.

[Example 18: Photo-aligned VA-type liquid crystal display element]
(1) Preparation of liquid crystal aligning agent The polymer and additive components (solid content equivalent: polymer (PI-15) 85 parts by mass, polymer (PMI-1) 10 parts by mass, and additive (AD-4) 5 parts by mass) were diluted with NMP, GBL, DEDG, and BC to obtain a solution with a solid content concentration of 4.0% by mass and a solvent composition ratio of NMP:GBL:DEDG:BC = 30:30:30:10 (mass ratio). This solution was filtered through a filter with a pore size of 0.2 μm to prepare a liquid crystal aligning agent (AL-24).

(2) Evaluation of Optical Properties (Transparency) The liquid crystal aligning agent (AL-24) prepared in (1) above was evaluated for transparency in the same manner as in Example 1. As a result, in this example, the evaluation was "good".
(3) Formation of a liquid crystal alignment film by photo-alignment method The liquid crystal alignment agent (AL-24) prepared in (1) above was applied to each electrode surface of two glass substrates having ITO electrodes using a spin coater, heated on a hot plate at 80°C for 1 minute, and then heated in an oven at 230°C with the interior substituted with nitrogen for 30 minutes to form a coating film with an average film thickness of 100 nm. A photo-alignment treatment was performed on the surface of this coating film by irradiating 20 mJ/ ^cm2 of linearly polarized ultraviolet light containing a 313 nm emission line using an Hg-Xe lamp from a direction tilted 40° from the substrate normal, thereby forming a liquid crystal alignment film.
(4) Manufacturing of VA-type liquid crystal display element An epoxy resin adhesive containing aluminum oxide spheres with a diameter of 3.5 μm was dispensed onto the outer periphery of the surface having the liquid crystal alignment film of one of the substrates prepared in (3) above, leaving a liquid crystal injection port, and then the surfaces of the pair of substrates having the liquid crystal alignment film were placed opposite each other and pressed together so that the projection directions of the optical axes of the ultraviolet rays on each substrate surface were antiparallel, and the adhesive was thermally cured at 150°C for 1 hour.
Next, negative nematic liquid crystal (MLC-6608, manufactured by Merck) was filled into the gap between the substrates through the liquid crystal filling port, which was then sealed with an epoxy adhesive. Furthermore, to remove flow alignment that occurred during liquid crystal injection, the substrate was heated to 120°C and then slowly cooled to room temperature. Next, polarizing plates were attached to both outer surfaces of the substrates so that their polarization directions were perpendicular to each other and at a 45° angle with the alignment treatment direction of the liquid crystal alignment film, thereby producing a VA-type liquid crystal display element.
(5) Evaluation of DC Afterimage Characteristics The liquid crystal display element manufactured in (4) above was evaluated for DC afterimage characteristics in the same manner as in Example 1. As a result, the liquid crystal display element in this example was evaluated as "good."

[Example 19]
In the same manner as in Example 18, except that the components contained in the liquid crystal alignment agent were changed as shown in the following Table 2, a liquid crystal alignment agent was prepared, a liquid crystal alignment film was formed by a photoalignment method, and a VA-type liquid crystal display element was manufactured and various evaluations were performed. The evaluation results are shown in Table 2 below.

In Table 2, the mass ratio of each component of the liquid crystal alignment agent indicates the blending ratio (parts by mass) of each compound per 100 parts by mass of the total of the polymer components and additive components used in preparing the liquid crystal alignment agent.

As shown in Table 2, the liquid crystal alignment agents of Examples 1 to 19, which contained polymer (P), had "good" optical properties (transparency) of the liquid crystal alignment film and "excellent" or "good" DC image retention characteristics of the liquid crystal display element, demonstrating a good balance of various properties. In contrast, the liquid crystal alignment agents of Comparative Examples 1 to 6, which did not contain polymer (P), had "poor" optical properties (transparency) of the liquid crystal alignment film and/or "poor" DC image retention characteristics of the liquid crystal display element, and were inferior to the Examples.

Here, the results of Examples 1 to 19 and Comparative Examples 1 to 6 will be considered.
The liquid crystal alignment agents of Examples 1 to 19 contain a polymer (P) having a partial structure (A). The fused ring skeleton of the partial structure (A) has a low ionization potential, and the cyclic structure facilitates in-plane orientation of molecular chains (π-π stacking) in a solid. Therefore, when formed into a liquid crystal alignment film, it is presumed that intermolecular hopping conduction is promoted, and charge (hole) transport properties are likely to be enhanced. Therefore, when formed into a liquid crystal display device, accumulated charges are likely to be relaxed, and DC image retention characteristics are thought to be improved.

Furthermore, in polymer (P), partial structure (A) tends to form a bent or twisted structure at the site adjacent to the fused ring. Therefore, in the fused ring skeleton in partial structure (A), the π-conjugated system of the fused ring is less likely to extend to adjacent sites, making it less likely to absorb light in the visible light range. As a result, it is thought that the optical properties (transparency) of the resulting liquid crystal alignment film are improved. In addition, because the fused ring skeleton in partial structure (A) tends to form a bent or twisted structure with adjacent sites, the fused ring in partial structure (A) has low crystallinity despite its high planarity. Therefore, when it is formed into a diamine or polymer, it exhibits excellent solubility in various solvents, and when it is formed into a liquid crystal alignment agent, it is thought that it exhibits excellent coatability (spin coating, inkjet printing, offset printing) and storage stability.

In addition, polymer (P) does not easily absorb light in the visible light range, and its electrical properties (dielectric constant, resistivity, etc.) change little when illuminated with a backlight, so it is thought that when used in a liquid crystal display element, it will be easy to suppress charge accumulation and the occurrence of flicker. Furthermore, it is thought that it will be possible to suppress deterioration of the liquid crystal alignment film when illuminated with a high-brightness backlight, and to obtain a liquid crystal display element with excellent long-term reliability and suppressed deterioration of DC afterimage characteristics.

On the other hand, the liquid crystal alignment agents of Comparative Examples 1 to 3 and 5 had "poor" DC afterimage characteristics. This is presumably due to their high ionization potential and low charge transport properties in the liquid crystal alignment film. Furthermore, the liquid crystal alignment agents of Comparative Examples 1, 2 and 5 had "poor" optical properties (transparency). This is presumably due to the liquid crystal alignment films obtained using polymers (PI-5) and (PI-6) being prone to oxidative degradation, resulting in poor transparency. The liquid crystal alignment agents of Comparative Examples 4 and 6 had "poor" optical properties (transparency). This is presumably due to the π-conjugated system easily extending throughout the entire repeating unit, making them more susceptible to excitation by lower-energy light and more likely to absorb light in the visible light range.

<Polymer evaluation by quantum chemical calculation>
[Example 20]
The physical properties of a polyimide (polymer represented by the following formula (PI-20)) obtained by polycondensation of a tetracarboxylic dianhydride (TA-1) and a diamine (DA-1) were evaluated by performing quantum chemical calculations on its repeating unit, a bissuccinimide represented by the following formula (SI-1). Calculations were performed using density functional theory (DFT) using Gaussian 16 (Revision B.01) manufactured by Gaussian Corporation, USA, as the quantum chemical calculation program.

(1) Evaluation of HOMO Level and DC Image Lag Characteristics The most stable structure in the ground state of bissuccinimide (SI-1) under vacuum was calculated using B3LYP as the functional and 6-31G(d) as the basis function. Furthermore, the van der Waals volume V (cm ³ /mol) of the obtained most stable structure was determined by the Monte Carlo method. Furthermore, a single-point energy calculation was performed using B3LYP as the functional and 6-311+G(d) as the basis function to calculate the energy level (eV) of the highest occupied molecular orbital (HOMO orbital). It has been found that the closer this energy level is to the work function of ITO (-4.5 to -5.0 eV), the more likely charge (hole) injection from the ITO electrode interface occurs, and charge accumulation during operation is more likely to occur. It has also been found that the lower this energy level is, the higher the ionization potential becomes, the more likely charge (hole) transportability is reduced, and charge relaxation during operation is less likely to occur. Regarding the evaluation of the DC image lag characteristics of bissuccinimide (SI-1), a HOMO level of −5.5 eV or more and less than −5.2 eV was rated as “good,” and a HOMO level of less than −5.5 eV or −5.2 eV or more was rated as “poor.” As a result, the present example was rated as “good.”

(2) Evaluation of Absorption Edge and Transparency For the most stable structure obtained in (1) above, the singlet excited state was calculated using time-dependent density functional theory (TD-DFT) with B3LYP as the functional and 6-311+G(d) as the basis function. For each electronic transition (excitation energy and oscillator strength), the molar extinction coefficient ε (L/mol/cm) at each wavelength was calculated with a half-width at half maximum of 0.25 eV, and the transmittance spectrum in a 100 nm thin film was obtained using the van der Waals volume V (cm ³ /mol) obtained in (1) above. Furthermore, from the obtained transmittance spectrum, the wavelength (absorption edge) at which the transmittance is 99% or more was calculated. Comparing the calculated results with the measured results, it has been found that under these calculation conditions, the absorption edge shifts to the longer wavelength side by about 40 nm. Regarding the evaluation of the transparency of bissuccinimide (SI-1), an absorption edge of less than 440 nm was rated as "good," and an absorption edge of 440 nm or more was rated as "poor." As a result, the present example was evaluated as "good."

[Examples 21 to 23, Comparative Examples 7 to 11]
The physical properties of polyimides (polymers (PI-21) to (PI-28)) were evaluated in the same manner as in Example 20, except that the type of diamine was changed as shown in Table 3 below. The evaluation results are shown in Table 3 below. Furthermore, Figs. 3 and 4 show the transmittance spectra of Examples 20 to 23 and Comparative Examples 7 to 11, respectively. Furthermore, Fig. 5 shows the molecular structures and molecular orbitals (HOMO and LUMO) of compounds (SI-1) to (SI-9) in Examples 20 to 23 and Comparative Examples 7 to 11.

In Table 3, diamines (DA-3a, DA-18 to DA-20) are compounds represented by the following formulas (DA-3a), (DA-18) to (DA-20), respectively.

As shown in Table 3, Examples 20 to 23, which used a copolymer of an aliphatic tetracarboxylic dianhydride and a specific diamine, had "good" transparency and "good" DC image retention characteristics based on quantum chemical calculations of the bissuccinimide, demonstrating a good balance of various properties. In contrast, Comparative Examples 7 to 11, which used a copolymer of an aliphatic tetracarboxylic dianhydride and a specific diamine, were inferior to the Examples in at least one of transparency and DC image retention characteristics, being "poor."

Here, the results of Examples 20-23 and Comparative Examples 7-11 will be considered. Comparing the results of Example 22 (diamine (DA-3a)) with Comparative Example 10 (diamine (DA-19)), and Example 23 (diamine (DA-4)) with Comparative Example 7 (diamine (DA-6)), Examples 22 and 23, which used a diamine having a bicarbazole ring, exhibited "good" DC image retention characteristics, whereas Comparative Examples 10 and 7, which used a diamine having a carbazole ring instead of a bicarbazole ring, exhibited "poor" DC image retention characteristics. This is presumably because the polymer having structural units derived from the diamine having a carbazole ring did not exhibit sufficient charge transport properties, whereas the polymer having structural units derived from the diamine having a bicarbazole ring exhibited sufficient charge transport properties.

Furthermore, when the results of Example 22 (diamine (DA-3a)) and Comparative Example 9 (diamine (DA-18)) were compared, Example 22, which used a diamine in which an oxygen atom was bonded to the carbon atom of the bicarbazole ring, had "good" transparency, whereas Comparative Example 9, which used a diamine in which a nitrogen atom was bonded to the carbon atom of the bicarbazole ring, had "poor" transparency. This is presumably because in Comparative Example 9, the π-conjugated system expanded via the nitrogen atom, shifting the absorption to longer wavelengths.

Low-energy electronic transitions are important because they affect absorption in the visible light region, and electronic transitions from HOMO to LUMO generally make a large contribution. For example, in Example 20, 93% of the lowest energy transitions (S ₀ -S ₁ transitions) were HOMO-LUMO transitions. Regarding HOMO-LUMO transitions, charge transfer (CT) transitions contributed significantly in Examples 20 and 21, while localized excitation (LE) transitions contributed significantly in Examples 22 and 23 and Comparative Examples 7 to 11. In Examples 20 and 21, the bicarbazole rings are linked via nitrogen atoms at the 9,9'-positions, and it is presumed that the electronic states are significantly different compared to Examples 22 and 23 and Comparative Examples 7 to 11.

[Synthesis Example 26]
Diamine (DA-1) was dissolved in NMP, and 2.0 molar equivalents of maleic anhydride relative to the amount of diamine was added, followed by a reaction at room temperature for 6 hours to obtain a 10 mass % solution of additive (AD-5) represented by the following formula (AD-5).

[Synthesis Example 27]
Polyamic acid (PI-29) was obtained in the same manner as in Synthesis Example 5, except that the types and molar ratios of the tetracarboxylic dianhydrides and diamines were changed as shown in Table 4. Note that the values in Table 4 indicate the proportion (mol %) of each compound used relative to the total amount (100 mol %) of the acid dianhydrides used in the synthesis, and the values in Table 4 indicate the proportion (mol %) of each compound used relative to the total amount (100 mol %) of the diamines used in the synthesis.

[Synthesis Examples 28 and 29]
Polyimides (PI-30, PI-31) were obtained in the same manner as in Synthesis Example 23, except that the types and molar ratios of the tetracarboxylic dianhydrides and diamines were changed as shown in Table 4 below.

[Examples 24 to 27]
In the above Example 1, except that the components contained in the liquid crystal alignment agent were changed as shown in Table 5 below and the solvent composition ratio was changed to NMP:BC:NEP:GBL=50:30:10:10 (mass ratio), a liquid crystal alignment agent was prepared and a liquid crystal alignment film was formed by a photoalignment method in the same manner as in Example 1, and an FFS-type liquid crystal display element was manufactured and various evaluations were performed. The evaluation results are shown in Table 5 below.

[Examples 28 to 30]
In the same manner as in Example 13, except that the components contained in the liquid crystal aligning agent were changed as shown in Table 5 below and the solvent composition ratio was changed to NMP:BC:NEP:GBL=50:30:10:10 (mass ratio), a liquid crystal aligning agent was prepared and a liquid crystal alignment film was formed by a rubbing method, and an FFS-type liquid crystal display element was manufactured and various evaluations were performed. The evaluation results are shown in Table 5 below.

In Table 5, the mass ratio of each component of the liquid crystal alignment agent indicates the blending ratio (parts by mass) of each compound per 100 parts by mass of the total of the polymer components and additive components used in preparing the liquid crystal alignment agent.

As shown in Table 5, the liquid crystal alignment agents of Examples 24 to 26, 28, and 29, which contained polymer (P), had "good" optical properties (transparency) for the liquid crystal alignment film and "excellent" DC image retention characteristics for the liquid crystal display element, demonstrating a good balance of various properties.

Furthermore, for the liquid crystal alignment agents of Examples 27 and 30 containing additive (AD-5), the optical properties (transparency) of the liquid crystal alignment film were "good," and the DC image retention characteristics of the liquid crystal display element were "good." Similar to the liquid crystal alignment agent containing polymer (P), the various properties were well-balanced. This is thought to be because, during the liquid crystal alignment film formation process, additive (AD-5) was converted to a bismaleimide compound, and dimerization reactions (coupling reactions) and crosslinking reactions (Michael addition reactions with the polymer's terminal amino groups, etc.) of the maleimide groups proceeded, or a polymer having partial structure (A) was produced by a polymerization reaction between maleimide groups.

From the above, it was found that the liquid crystal aligning agent of the present disclosure containing compound (P) can produce liquid crystal devices with excellent optical properties (transparency) and DC afterimage properties.

Claims (10)

A liquid crystal aligning agent comprising a compound (P) having, as the partial structure (A) represented by the following formula (1), at least one selected from the group consisting of a partial structure represented by the following formula (x-1), a partial structure represented by the following formula (x-2), and a partial structure represented by the following formula (3):
*-Y ¹ -A ¹ -A ² -Y ² -*...(1)
(In formula (1), A ¹ and A ² are each independently a divalent group having a fused ring structure in which an aromatic ring is fused to the 2,3-position and the 4,5-position of at least one heteroaromatic ring selected from the group consisting of a pyrrole ring, a furan ring, and a thiophene ring. However, in A ¹ and A ² , at least one carbon atom of the aromatic ring constituting the fused ring structure is bonded to each other by a single bond. Y ¹ and Y ² are each independently a carbon atom, an oxygen atom, a sulfur atom, or a divalent organic group bonded to the fused ring structure in A ¹ or A ² via * ⁵ -NR ⁵ -CO-, or * ² -NR ⁴ -* ³ . R ⁴ is a hydrogen atom or a monovalent organic group, or is bonded to another group and represents a part of a ring structure formed together with the nitrogen atom to which R ⁴ is bonded. R ⁵ is a hydrogen atom or a monovalent organic group. "* ² " and "* ^"5 " represents a bond bonded to the fused ring structure in ^A1 or ^A2 . "* ³ " represents a bond bonded to -CO-. "*" represents a bond.)
(In formulas (x-1) to (x-2), G ¹ and G ² each independently represent —O— or —S—. “*” represents a bond.)
(In formula (3), R ² is a halogen atom, a hydroxy group, or a monovalent organic group. R ³ is a hydrogen atom or a monovalent organic group. Y ⁴ is a carbon atom, an oxygen atom, a sulfur atom, or a divalent organic group bonded to the fused ring structure in the formula via * ⁵ -NR ⁵ -CO-, or is * ² -NR ⁴ -* ³ . R ⁴ is a hydrogen atom or a monovalent organic group, or is bonded to another group to represent a part of a ring structure formed together with the nitrogen atom to which R ⁴ is bonded. R ⁵ is a hydrogen atom or a monovalent organic group. "* ² " and "* ⁵ " represent bonds bonded to the fused ring structure in the formula. "* ³ " represents a bond bonded to -CO-. a2 is an integer of 0 to 3. When there are multiple R ^2s in the formula , the multiple R ^2s may be the same or different. The multiple Y ⁴ may be the same or different from each other. Multiple a2's in the formula may be the same or different from each other. "*" represents a bond. The liquid crystal aligning agent according to claim 1, wherein the partial structure (A) is at least one selected from the group consisting of the following formulas (x-1) to (x-4):
(In formulas (x-1) to (x-4), G ¹ and G ² are each independently —O— or —S—. ³ and Z ⁴ are each independently —O— or —S—. ¹² and R ¹³ are each independently a hydrogen atom or a monovalent organic group having 1 to 8 carbon atoms. "*" represents a bond. The liquid crystal aligning agent according to claim 1 or 2 , wherein the compound (P) is a polymer. The compound (P) is a polymer having a structural unit derived from at least one selected from the group consisting of a diamine having a partial structure represented by the above formula (x-1) , a diamine having a partial structure represented by the above formula (x-2), and a diamine having a partial structure represented by the above formula (3) (wherein, in the above formula (3), R ⁴ is a hydrogen atom or a monovalent organic group). The liquid crystal aligning agent according to any one of claims 1 to 3 . The compound (P) is a polymer having at least one partial structure selected from the group consisting of a partial structure represented by the following formula (5) and a partial structure represented by the following formula (6): A liquid crystal aligning agent according to any one of claims 1 to 4.
(In formulas (5) and (6), ^X1 is a tetravalent organic group. ^X2 is a divalent organic group represented by the above formula ( x-1 ) , the above formula (x-2) , or the following formula (8). ^R8 , ^R9 , ^R10 , and ^R11 are each independently a hydrogen atom or a monovalent organic group having 1 to 8 carbon atoms.)
(In formula (8), ^R2 is a halogen atom, a hydroxy group, or a monovalent organic group. ^R3 is a hydrogen atom or a monovalent organic group. ^Y6 is a single bond or a divalent organic group bonded to the fused ring structure in the formula via a carbon atom, an oxygen atom, a sulfur atom, or * ⁵ - ^NR5 -CO-. ^R5 is a hydrogen atom or a monovalent organic group. * ⁵ represents a bond to the fused ring structure in the formula. a2 is an integer of 0 to 3. When there are multiple ^R2s in the formula, the multiple ^R2s are the same or different. Multiple ^Y6s in the formula are the same or different. Multiple a2s in the formula are the same or different. * represents a bond.) The liquid crystal aligning agent according to claim 5 , wherein the X ¹ is a tetravalent aliphatic hydrocarbon group. Contains a polymer component and an additive component,
The liquid crystal aligning agent according to claim 1 , wherein the compound (P) is an additive component. The liquid crystal aligning agent according to any one of claims 1 to 7 , further comprising a polymer not having the partial structure (A). A liquid crystal alignment film formed using the liquid crystal aligning agent according to any one of claims 1 to 8 . A liquid crystal device comprising the liquid crystal alignment film according to claim 9 .