TWI904366B - Methods for manufacturing liquid crystal alignment agents, liquid crystal alignment films, liquid crystal elements, polyamides, polyamide esters and polyimides, diamines, tetracarboxylic dianhydrides, and polymers. - Google Patents

Abstract

This invention provides a liquid crystal alignment agent that can produce a liquid crystal element with good liquid crystal alignment, excellent voltage retention characteristics, and suppression of display quality degradation caused by external forces. The liquid crystal alignment agent contains a polymer [A] having a partial structure (a) represented by formula (1) in the main chain. In formula (1), ^R1 and ^R2 are divalent groups formed by bonding -C( ^R5 )( ^R6 )-, -O-, -S-, -CO-, -COO-, -NR7-, ^-NR7 - ^NR8- , ^-NR7 -CO- ^{O-, -NR7 -} CO- ^NR8- , aromatic hydrocarbon rings, aromatic heterocyclic rings or nitrogen-containing non-aromatic heterocyclic rings with the carbonyl group in formula (1). ^R3 and ^R4 are hydrogen atoms, halogen atoms, or alkyl groups having 1 to 3 carbon atoms, or represent a ring structure formed by the combination of ^R3 and ^R4 .

Description

Methods for manufacturing liquid crystal alignment agents, liquid crystal alignment films, liquid crystal elements, polyamides, polyamide esters and polyimides, diamines, tetracarboxylic dianhydrides, and polymers.

This invention relates to a liquid crystal alignment agent, a liquid crystal alignment film, a liquid crystal element, a polymer, a method for manufacturing the same, and a method for manufacturing a compound.

Previously, various driving methods were developed for liquid crystal elements, including different electrode structures and the physical properties of the liquid crystal molecules used. These included known types such as twisted nematic (TN) and super twisted nematic (STN) types, vertical alignment (VA) types, multi-domain vertical alignment (MVA) types, in-plane switching (IPS) types, fringe field switching (FFS) types, and optically compensated bent (OCB) types. These liquid crystal elements all possess liquid crystal alignment films used to align the liquid crystal molecules. Generally, liquid crystal alignment films are formed by coating a liquid crystal alignment agent, which is made by dissolving or dispersing polymer components in an organic solvent, onto the surface of a substrate, preferably by heating the substrate.

In recent years, large-screen and high-resolution LCD TVs have become mainstream. Furthermore, the widespread adoption of small display terminals such as smartphones and personal computers (PCs) has further increased the demands for high-quality liquid crystal components. To meet these high-quality requirements, various liquid crystal alignment agents have been proposed (for example, see Patent 1). Patent 1 discloses a crosslinking compound that contains polyimide or a polyimide precursor, as well as a low-molecular-weight compound to improve the hardness of the liquid crystal alignment film. [Prior Art Documents] [Patent Documents]

[Patent Document 1] International Publication No. 2020/171128

[The problem the invention aims to solve]

With the increasing precision of liquid crystal elements, the quality requirements have become more stringent. For example, for liquid crystal elements, not only is it necessary to further improve the liquid crystal alignment and voltage retention, but it is also required that the display quality not be compromised by physical pressure such as vibration or tapping during transportation. In particular, with the advancement of thin-film technology in the glass panel that serves as the substrate of the liquid crystal element, the physical pressure applied to the internal components has further increased. On the other hand, as before, it has become difficult to maintain display quality simply by adding crosslinking compounds.

This invention addresses the aforementioned problems, with the primary objective of providing a liquid crystal alignment agent that yields a liquid crystal element with excellent liquid crystal alignment, superior voltage retention characteristics, and suppressed display quality degradation caused by external forces. [Means for Solving the Problems]

The inventors have conducted intensive research to solve the aforementioned problem and discovered that it can be solved by using polymers with a specific carbon-carbon unsaturated structure, thus completing the present invention. Specifically, the following means are provided according to the present invention.

<1> A liquid crystal alignment agent comprising a polymer [A] having a partial structure (a) represented by formula (1) on the main chain, [Chemical 1] (In formula (1), ^R1 and ^R2 are independently divalent groups formed by bonding -C( ^R5 )( ^R6 )-, -O-, -S-, -CO-, -COO-, -NR7-, -NR7- ^NR8- , ^-NR7 -CO-O-, ^-NR7 -CO- ^NR8- , aromatic hydrocarbon rings, aromatic heterocycles or ^nitrogen -containing non-aromatic heterocycles with the carbonyl group in formula (1); ^{R3 and R4} are independently hydrogen atoms, halogen atoms or alkyl groups having 1 to 3 carbon atoms, or represent a ring structure formed by the combination of ^R3 and ^R4 together with the carbon atoms bonded to ^R3 and ^R4 ; ^R5 and R ^R6 is independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms; ^R7 and ^R8 are independently hydrogen atoms or monovalent organic groups; "*" indicates a bond.

<2> A liquid crystal alignment film formed using a liquid crystal alignment agent according to <1>. <3> A liquid crystal element comprising the liquid crystal alignment film according to <2>. <4> A polyamide, polyamide ester, and polyimide, wherein a portion of the structure represented by formula (1) is present in the main chain.

<5> A method for producing a diamine, wherein a compound represented by formula (5) is used in a raw material to produce a diamine represented by formula (2), [Chemistry 2] (In equation (5), ^R9 is a single bond or a divalent organic group) [Chemistry 3] In formula (2), ^A1 and ^A2 are, independently, single-bonded, divalent alicyclic, or divalent aromatic cyclic groups; ^R1 and ^R2 are, independently, divalent organic groups bonded to the carbonyl group in formula ( ² ) using -C(R5)( ^R6 )-, -O-, -S-, ^-CO- , -COO-, -NR7-, ^-NR7 -NR8-, ^-NR7 -CO-O-, ^-NR7 -CO- ^NR8- , aromatic hydrocarbon rings, aromatic heterocycles, or nitrogen-containing non-aromatic heterocycles; ^{R3 and R4} are, independently, hydrogen atoms, halogen atoms, or alkyl groups having 1 to 3 carbon atoms, or represent the carbon atom and ^R3 bonded to ^R4 in combination with each ^other . The ring structure is formed by ^{the four} bonded carbon atoms; ^R5 and ^R6 are independently hydrogen atoms, halogen atoms, alkyl groups with 1 to 8 carbon atoms, alkenyl groups with 1 to 8 carbon atoms, or alkoxy groups with 1 to 8 carbon atoms, respectively; ^R7 and ^R8 are independently hydrogen atoms or monovalent organic groups, respectively; m1 is an integer from 1 to 3; when m1 is 2 or 3, multiple ^R1 to ^R4 are the same or different from each other.

<6> A method for producing a tetracarboxylic dianhydride, wherein the tetracarboxylic dianhydride represented by formula (5) is used in the raw materials to produce the tetracarboxylic dianhydride represented by formulas (3) and (4) below, [Chemical 4] In formulas (3) and (4), ^A3 and ^A4 are each independently trivalent aromatic cycloalkanes or aliphatic cycloalkanes; ^R1 and ^R2 are each independently divalent organic groups bonded to the carbonyl group in formulas (3) and ( ⁴ ) using -C(R5)( ^R6 )-, -O-, ^-S- , -CO-, -COO-, -NR7-, ^-NR7 - ^NR8- , ^-NR7 -CO-O-, ^-NR7 -CO- ^NR8- , aromatic hydrocarbon rings, aromatic heterocycles or nitrogen-containing non-aromatic heterocycles; ^R3 and ^R4 are each independently hydrogen atoms, halogen atoms or alkyl groups having 1 to 3 carbon atoms, or represent the carbon atom and R bonded to ^R3 by ^R3 and ^R4. The ring structure is formed by ^{the four} bonded carbon atoms; ^R5 and ^R6 are independently hydrogen atoms, halogen atoms, alkyl groups with 1 to 8 carbon atoms, alkenyl groups with 1 to 8 carbon atoms, or alkoxy groups with 1 to 8 carbon atoms, respectively; ^R7 and ^R8 are independently hydrogen atoms or monovalent organic groups, respectively; m2 is an integer from 1 to 3; n1 and n2 are independently integers from 1 to 3, respectively; when m2 is 2 or 3, multiple ^R1 to ^R4 are the same or different from each other).

<7> A method for manufacturing a polymer, comprising polymerizing monomers of at least one compound selected from the group consisting of a diamine obtained by the method according to <5> and a tetracarboxylic dianhydride obtained by the method according to <6>, to produce polyamide, polyamide ester and polyimide according to <4>. [Effects of the Invention]

According to the liquid crystal alignment agent of the present invention, a liquid crystal element with good liquid crystal alignment, excellent voltage holding characteristics, and suppression of display quality degradation under external force (such as external force based on vibration or impact) can be obtained.

《Liquid Crystal Alignment Agent》 The following describes the components contained in the liquid crystal alignment agent of this invention, as well as other components that may be added as needed.

Furthermore, in this specification, the term "alkane" encompasses chain-like hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons. "Chain-like hydrocarbons" refers to linear and branched hydrocarbons whose main chain does not contain a ring structure and consists solely of chain-like structures. These chains can be saturated or unsaturated. "Alicyclic hydrocarbons" refers to hydrocarbons that contain only alicyclic hydrocarbon structures as ring structures and do not contain aromatic ring structures. This does not necessarily mean that the hydrocarbon structure consists solely of alicyclic hydrocarbons; it also includes groups that have chain-like structures in a portion of their structure. The term "aromatic hydrocarbon" refers to a hydrocarbon that contains an aromatic ring structure as its ring structure. It does not have to consist solely of an aromatic ring structure; it may also contain chain structures or alicyclic hydrocarbon structures in a portion of it.

The term "main chain" refers to the longest "trunk" portion of the polymer's atomic chain. Furthermore, the "trunk" portion may contain ring structures. The term "side chain" refers to portions that branch off from the polymer's "trunk." "Aromatic ring" encompasses both aromatic hydrocarbon rings and aromatic heterocycles. "Organic group" refers to a radical formed by removing any hydrogen atom from a carbon-containing compound (i.e., an organic compound). "Tetracarboxylic acid derivative" encompasses tetracarboxylic dianhydrides, tetracarboxylic acid diesters, and tetracarboxylic acid diester dihalides.

The liquid crystal alignment agent of this invention contains a polymer [A] having a partial structure (a) represented by the following formula (1) on the main chain. [Chemical 5] In formula (1), ^R1 and ^R2 are independently divalent groups formed by bonding -C( ^R5 )( ^R6 )-, -O-, -S-, -CO-, -COO-, -NR7-, ^-NR7 - ^NR8- , ^-NR7 -CO-O-, ^-NR7 -CO- ^NR8- , aromatic hydrocarbon rings, aromatic heterocycles, or ^nitrogen -containing non-aromatic heterocycles to the carbonyl group in formula (1). ^R3 and ^R4 are independently hydrogen atoms, halogen atoms, or alkyl groups having 1 to 3 carbon atoms, or represent a ring structure formed by the combination of ^R3 and ^R4 together with the carbon atoms bonded to ^R3 and ^R4 . ^R5 and R ^R6 is independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms. ^R7 and ^R8 are independently a hydrogen atom or a monovalent organic group. (* indicates a bond)

<Polymer [A]> ·Regarding partial structure (a) In the case that ^R1 and ^R2 in the formula (1) are divalent groups bonded to the carbonyl group in the formula (1) by -C( ^R5 )( ^R6 )-, the alkyl group having 1 to 8 carbons, the alkenyl group having 1 to 8 carbons, and the alkoxy group having 1 to 8 carbons represented by ^R5 and ^R6 can be either linear or branched. Among them, ^R5 and ^R6 are also preferably hydrogen atoms or alkyl groups having 1 to 3 carbons, and more preferably hydrogen atoms (i.e., the case where -C( ^R5 )( ^R6 )- is methylene).

In the case that ^R1 and ^R2 in the above formula (1) are divalent groups bonded to the carbonyl group in the above formula (1) by ^-NR7- , ^-NR7 - ^NR8- , ^-NR7 -CO-O- and ^-NR7 -CO- ^NR8- , ^R7 and R8 are monovalent organic groups represented by the carbonyl group in the above formula (1), the monovalent organic groups represented by R7 and ^R8 are preferably monovalent hydrocarbons with 1 to 10 carbon atoms, or monovalent deionizable groups that can be deionized by heat or light (hereinafter also referred to as "deionizable groups").

When the monovalent organic group represented by ^R7 and ^R8 is a monovalent hydrocarbon, specific examples of the hydrocarbon include: alkyl groups having 1 to 6 carbon atoms, cycloalkyl groups having 4 to 10 carbon atoms, aryl groups having 6 to 10 carbon atoms, and aralkyl groups having 6 to 10 carbon atoms. Among these, alkyl groups having 1 to 3 carbon atoms and phenyl groups are preferred, and alkyl groups having 1 to 3 carbon atoms are more preferred.

When the monovalent organic groups represented by ^R7 and ^R8 are monovalent deionizable groups, the deionizable group is preferably a thermally deionizable group that deionizes by heat (preferably heating during film formation). Specific examples of thermally deionizable groups include: tert-butoxycarbonyl (Boc group), benzyloxycarbonyl, 1,1-dimethyl-2-halogenated ethyloxycarbonyl, allyloxycarbonyl, 2-(trimethylsilyl)ethoxycarbonyl, etc. Among these, the Boc group is particularly preferred in terms of excellent thermal deionization and the reduction of the amount of deionized structure remaining in the film.

^R7 and ^R8 are preferably hydrogen atoms, alkyl groups having 1 to 3 carbon atoms, or monovalent thermally deionizable groups, and more preferably hydrogen atoms, alkyl groups having 1 to 3 carbon atoms, or tert-butoxycarbonyl groups.

When ^R1 and ^R2 are groups bonded to the carbonyl group in formula (1) using an aromatic hydrocarbon ring, an aromatic heterocyclic ring, or a nitrogen-containing non-aromatic heterocyclic ring, examples of aromatic hydrocarbon rings include benzene rings, naphthalene rings, and anthracene rings. Examples of aromatic heterocyclic rings include nitrogen-containing aromatic heterocyclic rings, oxygen-containing aromatic heterocyclic rings, and sulfur-containing aromatic heterocyclic rings. Specific examples of these include pyridine rings, pyrimidine rings, darazine rings, and pyrazine rings; examples of oxygen-containing aromatic heterocyclic rings include furan rings; and examples of sulfur-containing aromatic heterocyclic rings include thiophene rings. Examples of nitrogen-containing non-aromatic heterocyclic rings include guanidine rings and guanazine rings. These rings may have substituents. Examples of substituents include: alkyl groups having 1 to 3 carbon atoms, alkoxy groups having 1 to 3 carbon atoms, halogen atoms, hydrogen atoms, cyano groups, etc.

^R1 and ^R2 can be any group that is bonded to the carbonyl group in formula ( ¹ ) by -C(R5)( ^R6 )-, -O-, -S-, -CO-, -COO-, -NR7-, ^-NR7 - ^NR8- , ^-NR7 -CO-O-, ^-NR7 -CO- ^NR8- , aromatic hydrocarbon ring, aromatic heterocycle or nitrogen-containing non-aromatic heterocycle ^. There are no particular restrictions on the structure of other parts. Furthermore, when ^R1 and ^R2 are bonded to the carbonyl group in formula (1) by -COO-, ^R1 and ^R2 can be bonded to the carbonyl group in formula (1) by oxygen atoms or by carbon atoms. In addition, when ^R1 and ^R2 are bonded to the carbonyl group in the formula (1) using ^-NR7 -CO-O-, ^R1 and ^R2 can be bonded to the carbonyl group in the formula (1) using nitrogen atoms, or they can be bonded to carbon atoms.

Specific examples of ^R1 and ^R2 include: -C( ^R5 )( ^R6 )-, -O-, -S-, -CO-, -COO-, -NR7-, -NR7- ^NR8- , -NR7-CO- ^{O-, -NR7-CO-NR8- , divalent chain} hydrocarbons, divalent aromatic hydrocarbon cycloalcohols, divalent aromatic heterocyclic groups, ^and divalent nitrogen-containing non-aromatic heterocyclic groups. Additionally, ^R1 and ^R2 can also be divalent organic groups formed by substitution with -O-, -S-, -CO-, -COO-, -NR7-, -NR7- ^NR8- , ^-NR7 -CO-O-, ^{-NR7 -} CO- ^NR8- , or heterocyclic groups ^, provided that the methylene groups in the divalent hydrocarbons are not adjacent.

In terms of improving the voltage holding ratio (VHR) of liquid crystal elements, obtaining liquid crystal elements with high reliability and minimal decrease in voltage holding ratio under long-term driving, obtaining liquid crystal elements that exhibit good liquid crystal alignment, and effectively suppressing the decline in display quality caused by vibration or impact, one or both of ^R1 and ^R2 are preferably groups with a chain hydrocarbon structure having one or more carbon atoms or divalent nitrogen-containing non-aromatic heterocyclic groups. Specifically, one or both of ^R1 and ^R2 are preferably divalent chain hydrocarbons with 1 or more carbon atoms, or divalent groups formed by substitution with -O-, -S-, -CO-, -COO-, -NR7-, -NR7- ^NR8- , -NR7-CO-O- or ^-NR7 -CO- ^NR8- under the condition that any methylene group in the chain hydrocarbons with ² or ^more carbon atoms is not adjacent (wherein, the carbonyl group in the formula ( ¹ ) is bonded by -C( ^R5 )( ^R6 )-, -O-, -S-, -CO-, -COO-, -NR7-, ^-NR7 - ^NR8- , ^-NR7 -CO- ^O- or ^-NR7 -CO- ^NR8- ), or divalent nitrogen-containing non-aromatic heterocyclic groups. Of these, one or both of ^R1 and ^R2 are particularly preferably divalent chain hydrocarbons having one or more carbon atoms, or divalent hydrocarbons formed by substitution with -O-, -S-, -CO-, -COO-, -NR7-, -NR7- ^NR8- , -NR7-CO-O-, or ^-NR7 -CO- ^NR8- under the condition that any methylene group in the chain hydrocarbons having two or more carbon atoms is not adjacent. Furthermore, specific examples and preferred examples of ^{R5 , R6} , ^R7 , and ^R8 can be found ^{in the} description above.

When ^R1 and ^R2 are divalent chain hydrocarbons, the chain hydrocarbons can be saturated or unsaturated, and can be linear or branched. In terms of improving the voltage retention rate of the liquid crystal element, obtaining a highly reliable liquid crystal element with minimal voltage retention rate decline under long-term driving, obtaining a liquid crystal element exhibiting good liquid crystal alignment, and suppressing the degradation of display quality caused by vibration or impact, the chain hydrocarbons represented by ^R1 and ^R2 are preferably alkyldiyl groups, and more preferably linear alkyldiyl groups. When ^R1 and ^R2 are divalent chain hydrocarbons, from the viewpoint of obtaining a liquid crystal element exhibiting high voltage retention and good liquid crystal alignment, the carbon number of the chain hydrocarbon is preferably 2 or more, and more preferably 3 or more. Furthermore, from the viewpoint of simultaneously achieving improved film strength (and consequently improved abrasion resistance) and improved voltage retention of the liquid crystal element, when ^R1 and ^R2 are chain hydrocarbons, the carbon number of ^R1 and ^R2 is preferably 20 or less, more preferably 15 or less, and even more preferably 10 or less.

When ^R1 and ^R2 are divalent groups formed by substitution with -O-, -S-, -CO-, -COO-, -NR7-, -NR7-NR8-, ^-NR7 -CO-O- or ^-NR7 -CO- ^NR8- under the condition that any methylene group in the chain hydrocarbon with ² or more carbons is not adjacent (hereinafter also referred to as "divalent group A"), ^one or both of ^R1 and ^R2 are preferably the group represented by the following formula ( ⁶ ). -R ¹⁰ -X ¹ -* ¹ ···（6） (In formula (6), R ¹⁰ is an alkyldiyl group. ^{X 1} is -O-, -S-, -CO-, -COO-, -NR ^7- , -NR ⁷ -NR ^8- , -NR ⁷ -CO-O- or -NR ⁷ -CO-NR ^8- . "* ¹ " indicates a bond bonded to the carbonyl group in formula (1). ^{R 7} and R ⁸ have the same meaning as in formula (1))

In formula (6), the alkyl diel represented by R ¹⁰ is preferably linear. The number of carbon atoms in the alkyl diel is preferably 1 to 10, more preferably 2 to 10, and even more preferably 2 to 5.

When ^R1 and ^R2 are divalent nitrogen-containing non-aromatic heterocyclic groups, the divalent nitrogen-containing non-aromatic heterocyclic group is preferably a substituted or unsubstituted 1,4-piperidinediyl or a substituted or unsubstituted 1,4-piperazinediyl.

In formula (1), ^R3 and ^R4 are preferably hydrogen atoms, fluorine atoms, or methyl groups, or represent a ring structure formed by the combination of ^R3 and ^R4 together with the carbon atoms bonded to ^R3 and ^R4 . Examples of ring structures formed by the combination of ^R3 and ^R4 include cyclic alkene rings with 5 to 10 ring members. Preferably, the ring structure is a cyclic alkene ring with 5 to 8 ring members. Of these, ^R3 and ^R4 are preferably hydrogen atoms, fluorine atoms, or methyl groups, and particularly preferably hydrogen atoms, in terms of further improving the film strength.

The base represented by -R ⁴ C=CR ³ - in formula (1) can be either cis or trans. In terms of improving the strength of the film, the base represented by -R ⁴ C=CR ³ - in formula (1) is preferably cis.

Among them, part of structure (a) is preferably the structure represented by equation (1-1) or equation (1-2) below. [Chemistry 6] In formula (1-1), ^R11 and ^R13 represent a nitrogen-containing non-aromatic heterocyclic structure where ^R11 is a hydrogen atom or a monovalent organic group and ^R13 is a single bond or an alkyl diester, or ^R11 and ^R13 are combined with each other and together with the nitrogen atom bonded to ^R11 . ^R12 and ^R14 represent a nitrogen-containing non-aromatic heterocyclic structure where ^R12 is a hydrogen atom or a monovalent organic group and ^R14 is a single bond or an alkyl diester, or ^R12 and ^R14 are combined with each other and together with the nitrogen atom bonded to ^R12 . ^R3 and ^R4 are independently hydrogen atoms, halogen atoms, and alkyl groups having 1 to 3 carbon atoms, respectively. "*" indicates a bond. In formula (1-2), ^R15 and R ^R16 is a single bond or an alkyl group, ^each independently representing a hydrogen atom, a halogen atom, ^or an alkyl group having 1 to 3 carbon atoms, respectively. (* indicates a bond.)

In equations (1-1) and (1-2), for the monovalent organic bases represented by ^R11 and ^R12 , examples can be listed that are the same bases as those exemplified in the description of ^R7 and ^R8 in equation (1). For ^R3 and ^R4 , examples can be listed that are the same bases as those exemplified in the description of ^R3 and ^R4 in equation (1).

When ^R13 and ^R14 are alkyldiyl groups, a straight-chain alkyldiyl group is preferred, and a straight-chain alkyldiyl group with 1 to 5 carbon atoms is more preferred. The ring structure formed by the combination of ^R11 and ^R13 , and the ring structure formed by the combination of ^R12 and ^R14 , are preferably substituted or unsubstituted 1,4-piperidinediyl groups, or substituted or unsubstituted 1,4-piperazindiyl groups.

In polymer [A], from the viewpoint of obtaining a liquid crystal element exhibiting good liquid crystal alignment and displaying high VHR and high reliability, the content ratio of structural units derived from the monomer having partial structure (a) is preferably 2 mol% or more relative to the total amount of monomer units in polymer [A]. From this viewpoint, the content ratio of structural units derived from the monomer having partial structure (a) is more preferably 5 mol% or more, and more preferably 7 mol% or more, relative to the total amount of monomer units in polymer [A]. Furthermore, the content ratio of structural units derived from the monomer having partial structure (a) can be appropriately set according to the main chain of polymer [A], and is, for example, 60 mol% or less, preferably 50 mol% or less relative to the total amount of monomer units in polymer [A]. Furthermore, in polymer [A], the structural unit derived from the monomer having a partial structure (a) may be only one type or more types.

The main framework of polymer [A] is not particularly limited. In terms of forming a liquid crystal alignment film with high affinity for liquid crystal and high mechanical strength and reliability, polymer [A] is preferably selected from at least one of the group consisting of polyamide, polyamide ester and polyimide.

The method for manufacturing polymer [A] is not particularly limited as long as it can incorporate a portion of the structure (a) into the polymer backbone. Regarding the ease of incorporating the portion of the structure (a) into the polymer backbone, polymer [A] is preferably manufactured by polymerization using a monomer having the portion of the structure (a) in the backbone. Regarding the ability to form a liquid crystal alignment film with high affinity for liquid crystals and high mechanical strength, the monomer having the portion of the structure (a) is preferably selected from at least one of the group consisting of a diamine compound having the portion of the structure (a) (hereinafter also referred to as "specific diamine") and a tetracarboxylic acid dianhydride having the portion of the structure (a) (hereinafter also referred to as "specific anhydride").

(Specific Diamine) The specific diamine is any monolithic form having a portion of structure (a) and two primary amino groups; there are no particular limitations on other partial structures. Specifically, the specific diamine is preferably a compound represented by the following formula (2). [Chemistry 7] (In formula (2), ^A1 and ^A2 are, independently, single-bonded, divalent alicyclic, or divalent aromatic cyclic groups. m1 is an integer from 1 to 3. ^R1 , ^R2 , ^R3 , and ^R4 have the same meaning as in formula (1). When m1 is 2 or 3, multiple ^R1 to ^R4 may be the same or different from each other.)

In formula (2), the divalent alicyclic groups represented by ^A1 and ^A2 are preferably groups formed by removing two hydrogen atoms from the ring portion of a substituted or unsubstituted alicyclic hydrocarbon ring. Examples of alicyclic hydrocarbon rings include cyclobutane rings, cyclopentane rings, cyclohexane rings, and cycloheptane rings. Examples of substituents introduced into the ring portion of the alicyclic hydrocarbon ring include alkyl groups with 1 to 5 carbon atoms, alkoxy groups with 1 to 5 carbon atoms, and halogen atoms.

The divalent aromatic cyclic groups represented by ^A1 and ^A2 are groups formed by removing two hydrogen atoms from the ring moiety of a substituted or unsubstituted aromatic ring. The aromatic ring is an aromatic hydrocarbon ring or an aromatic heterocyclic ring, preferably an aromatic hydrocarbon ring or a nitrogen-containing aromatic heterocyclic ring. Examples of substituents introduced into the ring moiety of the aromatic ring include: alkyl groups having 1 to 5 carbon atoms, alkoxy groups having 1 to 5 carbon atoms, halogen atoms, etc.

As specific examples of ^A1 and ^A2 being divalent aromatic cyclic groups, divalent aromatic hydrocarbon cyclic groups can be categorized as groups formed by removing any hydrogen atom from the ring portion of a benzene ring, biphenyl ring, naphthalene ring, or anthracene ring; divalent nitrogen-containing aromatic heterocyclic groups can be categorized as groups formed by removing two arbitrary hydrogen atoms from the ring portion of a pyridine ring, pyrimidine ring, darazine ring, or pyrazine ring. From the viewpoint of achieving high density liquid crystal alignment films, the divalent aromatic cyclic groups represented by ^A1 and ^A2 are preferably substituted or unsubstituted phenylene, biphenylene, or pyridinium dimethyl groups, and more preferably substituted or unsubstituted phenylene groups.

From the perspective of obtaining a highly reliable liquid crystal element with minimal decrease in voltage retention rate (VHR) under long-term driving conditions, and from the perspective of obtaining a liquid crystal element exhibiting good liquid crystal alignment, ^A1 and ^A2 are preferably divalent alicyclic or divalent aromatic cyclic groups, and more preferably divalent aromatic cyclic groups. From the perspective of liquid crystal alignment and ease of synthesis, m1 is preferably 1 or 2. Furthermore, from the perspective of improving the improvement effect brought about by the introduction portion structure (a), m1 is preferably 2 or more. From the perspective of liquid crystal alignment and ease of synthesis, and the improvement effect of improving the voltage retention rate brought about by the introduction portion structure (a), m is particularly preferably 2.

Preferred examples of specific diamines include compounds represented by formula (2-1) and formula (2-2) below. [Chemistry 8] (In equations (2-1) and (2-2), ^Ar1 and ^Ar2 are each independently a divalent aromatic cyclic group. m1 is an integer from 1 to 3. ^R3 , ^R4 , ^R11 , ^R12 , ^R13 , ^R14 , ^R15 and ^R16 have the same meaning as in equations (1-1) and (1-2).)

Specific examples of diamines include compounds represented by formulas (3-1) to (3-30) below. Furthermore, in the compounds represented by formulas (3-1) to (3-30) below, the carbon-carbon unsaturated bond between the two carbonyl groups is not structurally heterogeneous and can be either cis or trans. [Chem. 9] [Chemistry 10] [Chemistry 11] [Chemistry 12] [Chemistry 13] [Chemistry 14]

(Synthesis of a specific diamine) There are no particular limitations on the method for synthesizing a specific diamine. A specific diamine can be produced, for example, by reacting maleic anhydride with an amine compound having a partial structure corresponding to “ ^-R1 - ^A1 - _NH2 ” in formula (2) (method 1A); or by reacting fumaric chloride with an amine compound having a partial structure corresponding to “ ^-R1 - ^A1 - _NH2 ” in formula (2) (method 2A). Alternatively, a specific diamine can also be produced using a compound represented by formula (5) as a starting material (method 3A). From an industrial point of view, it is desirable to obtain a useful diamine with a small number of steps. In this regard, method 3A is preferred in that it allows for the introduction of two or more partial structures (a) into the specific diamine with a small number of steps. [Chemistry 15] (In equation (5), ^R9 is a single bond or a divalent organic group)

In method 3A, the compound represented by formula (5) and an amine compound having a partial structure corresponding to " ^-R1 - ^A1 - _NH2 " in formula (2) are reacted in a solvent as needed. The solvent is preferably an organic solvent capable of dissolving the raw materials. In method 3A, the reaction temperature is, for example, 0°C to 80°C, and the reaction time is, for example, 30 minutes to 12 hours.

In formula (5), the divalent organic group represented by R ⁹ can include divalent hydrocarbons with 1 to 20 carbon atoms, and divalent groups containing -O-, -S-, etc., between the carbon-carbon bonds of the hydrocarbon. For example, by reacting the compound represented by formula (5) with the compound represented by formula (7) below, the compound represented by formula (8) below can be obtained as a specific diamine. [Chemistry 16] (In the process, ^R9 is a single-bond or divalent organic group. ^A1 has the same meaning as the above formula (2), and ^R1 has the same meaning as the above formula (1).)

(Specific anhydride) A specific anhydride is simply a monolith having part of structure (a) and two anhydride groups; there are no particular limitations on other parts of the structure. Specifically, the specific anhydride is preferably selected from at least one of the groups consisting of compounds represented by formula (3) below and compounds represented by formula (4) below. [Chemistry 17] (In equations (3) and (4), ^A3 and ^A4 are trivalent aromatic cycloalloys or aliphatic cycloalloys, respectively. m2 is an integer from 1 to 3. n1 and n2 are integers from 1 to 3, respectively. ^R1 , ^R2 , ^R3 and ^R4 have the same meaning as in equation (1). When m2 is 2 or 3, multiple ^R1 to ^R4 may be the same or different from each other.)

In formulas (3) and (4), the trivalent aliphatic cyclogroups represented by ^A3 and ^A4 can be examples of groups formed by removing three hydrogen atoms from the ring portion of an alicyclic hydrocarbon such as a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, or a cycloheptane ring. The alicyclic hydrocarbon may have substituents. Examples of substituents include alkyl groups having 1 to 5 carbon atoms, alkoxy groups having 1 to 5 carbon atoms, and halogen atoms.

The trivalent aromatic cyclic groups represented by ^A3 and ^A4 are groups formed by removing three hydrogen atoms from the ring moiety of a substituted or unsubstituted aromatic ring. The aromatic ring is an aromatic hydrocarbon ring or an aromatic heterocyclic ring, preferably an aromatic hydrocarbon ring or a nitrogen-containing aromatic heterocyclic ring. Examples of substituents introduced into the ring moiety of the aromatic ring include: alkyl groups having 1 to 5 carbon atoms, alkoxy groups having 1 to 5 carbon atoms, halogen atoms, etc. From the viewpoint of achieving high density liquid crystal alignment films, the trivalent aromatic cyclic groups represented by ^A3 and ^A4 are preferably groups having a benzene ring, a biphenyl ring, or a pyridine ring, and more preferably groups having a benzene ring.

From the perspective of obtaining a highly reliable liquid crystal element with minimal decrease in voltage retention rate (VHR) under long-term driving conditions, and from the perspective of obtaining a liquid crystal element exhibiting good liquid crystal alignment, ^A3 and ^A4 are preferably trivalent aromatic cyclic groups, and more preferably trivalent groups having a benzene ring. From the perspective of liquid crystal alignment and ease of synthesis, m2 is preferably 1 or 2. Furthermore, from the perspective of improving the improvement effect brought about by the introduced portion structure (a), m2 is preferably 2 or more.

Preferred examples of specific acid anhydrides include: compounds represented by formula (3-1), compounds represented by formula (3-2), compounds represented by formula (4-1), and compounds represented by formula (4-2). [Chemistry 18] (In formulas (3-1) and (3-2), ^Ar3 and ^Ar4 are each independently trivalent aromatic cyclic groups. m2 is an integer from 1 to 3. ^R3 , ^R4 , ^R11 , ^R12 , ^R13 , ^R14 , ^R15 , and ^R16 have the same meaning as in formulas (1-1) and (1-2).) [Chemistry 19] (In equations (4-1) and (4-2), m2 is an integer from 1 to 3. n1 and n2 are each an integer from 1 to 3 independently. ^R3 , ^R4 , ^R11 , ^R12 , ^R13 , ^{R14, R15 and R16} have the same meaning as in equations (1-1) and (1-2).)

In formulas (3-1), (3-2), (4-1) and (4-2), from the viewpoint of ease of synthesis of the compound, ^R13 , ^R14 , ^R15 and ^R16 are preferably single bonds.

Specific examples of particular acid anhydrides include compounds represented by formulas (4-1) to (4-3) below. Furthermore, in the compounds represented by formulas (4-1) to (4-3) below, the carbon-carbon unsaturated bond between the two carbonyl groups is not structurally heterogeneous and can be either cis or trans. [Chem. 20]

(Synthesis of Specific Anhydrides) There are no particular limitations on the method for synthesizing specific anhydrides. Specific anhydrides can be produced, for example, by reacting fumaric acid chloride with an amine compound having a partial structure corresponding to the “-R ¹ -anhydride group” in formula (3) or (4) (method 1B). Alternatively, specific anhydrides can also be produced using compounds represented by formula (5) below as raw materials (method 2B). From an industrial point of view, it is ideal to obtain useful tetracarboxylic acid dianhydrides with a small number of steps. In this regard, method 2B is preferred in terms of introducing more than two partial structures (a) into the specific anhydride with a small number of steps. [Chem. 21] (In equation (5), ^R9 is a single bond or a divalent organic group)

In method 2B, the compound represented by formula (5) and an amine compound having a partial structure corresponding to the "-R ¹ -anhydride group" in formula (3) or (4) are reacted in a solvent as needed. The solvent is preferably an organic solvent capable of dissolving the raw materials. In method 2B, the reaction temperature is, for example, 0°C to 80°C, and the reaction time is, for example, 30 minutes to 12 hours.

In formula (5), the divalent organic group represented by R ⁹ can include divalent hydrocarbons with 1 to 20 carbon atoms, and divalent groups containing -O-, -S-, etc., between the carbon-carbon bonds of the hydrocarbon. For example, by reacting the compound represented by formula (5) with the compound represented by formula (9) below, the compound represented by formula (10) below can be obtained as a specific acid anhydride. [Chemistry 22] (In the process, ^R9 is a single bond or a divalent organic group. ^A5 is a single bond or an alkyldiyl group. ^R1 has the same meaning as in the above formula (1). n1 is an integer from 1 to 3.)

<Polyamide> When polymer [A] is polyamide, the polyamide (hereinafter also referred to as "polyamide [A]") can be exemplified by: [1] a method for reacting a tetracarboxylic dianhydride containing a specific acid dianhydride with a diamine compound; [2] a method for reacting a tetracarboxylic dianhydride with a diamine compound containing a specific diamine, etc. Alternatively, the methods described in [1] and [2] can be combined.

(Tetracarboxylic dianhydride) In the synthesis of polyacrylic acid [A], one type of tetracarboxylic dianhydride may be used alone, or two or more may be used in combination. The tetracarboxylic dianhydride used in the synthesis of polyacrylic acid [A] may be only a specific acid dianhydride, or it may include tetracarboxylic dianhydrides that do not possess part of the structure (a) (hereinafter also referred to as "other acid dianhydrides"). Examples of other acid dianhydrides include, for example, chain-like aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, and aromatic tetracarboxylic dianhydrides.

Specific examples of other acid dianhydrides include chain-like aliphatic tetracarboxylic dianhydrides such as 1,2,3,4-butanetetracarboxylic dianhydride and ethylenediaminetetraacetic acid dianhydride; and alicyclic tetracarboxylic dianhydrides such as 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 2,3,5-tricarboxylated cyclopentylacetic acid dianhydride, 5-(2,5-dioxotetrahydrofuran-3-yl)-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione, and 5-(2,5-dioxotetrahydrofuran-3-yl)-8-methyl-3a,4,5,9b-tetrahydronaphtho[1,2-c]furan-1,3-dione. Furan-1,3-dione, 2,4,6,8-tetracarboxylic bicyclic [3.3.0]octane-2:4,6:8-dianhydride, cyclopentanetetracarboxylic dianhydride, cyclohexanetetracarboxylic dianhydride, 3,5,6-tricarboxy-2-carboxymethylnorbornene-2:3,5:6-dianhydride, etc.; Aromatic tetracarboxylic dianhydrides may include: pyromellitic dianhydride, 4,4'-(hexafluoroisopropyl)diphthalic anhydride, ethylene glycol dimethacrylate, 4,4'-carbonyldiphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, etc. In addition, tetracarboxylic dianhydrides described in Japanese Patent Application Publication No. 2010-97188 may be used.

Regarding the acquisition of liquid crystal alignment films with high solubility and exhibiting good liquid crystal alignment and electrical properties, the other dianhydrides used in the synthesis of polyacrylic acid [A] are preferably at least one of the group consisting of chain-like aliphatic tetracarboxylic dianhydrides and alicyclic tetracarboxylic dianhydrides, more preferably alicyclic tetracarboxylic dianhydrides. The proportion of alicyclic tetracarboxylic dianhydrides used relative to the total amount of tetracarboxylic dianhydrides used in the synthesis of polyacrylic acid [A] is preferably 20 mol% or more, more preferably 40 mol% or more, and even more preferably 50 mol% or more.

When polyamide [A] is manufactured by the method described in [1], the proportion of a specific acid dianhydride used is preferably 20 mol% or more, more preferably 30 mol% or more, and even more preferably 40 mol% or more, relative to the total amount of tetracarboxylic acid dianhydride used in the synthesis of polyamide [A].

(Diamine Compounds) In the synthesis of polyamide [A], one diamine compound may be used alone, or two or more may be used in combination. The diamine compound used in the synthesis of polyamide [A] may be only a specific diamine, or may include diamine compounds that do not possess part of structure (a) (hereinafter also referred to as "other diamines"). Examples of other diamines include, for example, chain-like aliphatic diamines, alicyclic diamines, aromatic diamines, and diamino organosilicones.

Other examples of diamines include chain-like aliphatic diamines such as meta-xylylenediamine and hexamethylenediamine; alicyclic diamines such as 1,4-diaminocyclohexane and 4,4'-methylenebis(cyclohexylamine); and aromatic diamines such as p-phenylenediamine, 4,4'-diaminodiphenylmethane, and 4... -Aminophenyl-4-aminobenzoic acid ester, 4,4'-diaminoazobenzene, 3,5-diaminobenzoic acid, 1,5-bis(4-aminophenoxy)pentane, 1,2-bis(4-aminophenoxy)ethane, 1,3-bis(4-aminophenoxy)propane, 1,6-bis(4-aminophenoxy)hexane, 6,6'-(pentamethylenedioxy)bis(3-aminopyridine), N,N'-bis(5-aminophenyl) ...4,4'-diaminophenyl)propane, 3,5-diaminobenzoic acid, 4,4'-diaminophenyl)propane, 3,5-diaminobenzoic acid, 3,5-diaminophenyl)propane, 3,4'-diaminophenyl -amino-2-pyridyl)-N,N'-di(tert-butoxycarbonyl)ethylenediamine, bis[2-(4-aminophenyl)ethyl]adipic acid, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylamine, 4,4'-diaminodiphenylethyl urea, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 1,4-bis(4-aminophenyl)hexafluoropropane (2,2'-dimethyl-4,4'-diaminobiphenyl, 4,4'-(phenylene diisopropylidene)bisphenylamine, 2,6-diaminopyrimidine, 2,4-diaminopyrimidine, 3,6-diaminopyrazole, N-methyl-3,6-diaminopyrazole, 3,6-diaminoacridine, monomers containing a diphenylamine structure, and the following formula (F-1) [Chem. 23] (In formula (F-1), ^R21 and ^R22 are each independently an alkyl group. ^R23 is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a protecting group. r1 is an integer from 1 to 3. When r1 is 2 or 3, multiple ^R22s may be the same or different from each other, and multiple ^R23s may be the same or different from each other.) The compounds represented by this formula are main-chain diamines. Hexadecyloxy-2,4-diaminobenzene, octadecyloxy-2,4-diaminobenzene, octadecyloxy-2,5-diaminobenzene, cholestyryloxy-3,5-diaminobenzene, cholestyryloxy-3,5-diaminobenzene, cholestyryloxy-2,4-diaminobenzene, cholestyryl ester of 3,5-diaminobenzoate, cholestyryl ester of 3,5-diaminobenzoate, 3,5- Lanostane diaminobenzoate, 3,6-bis(4-aminobenzoyloxy)cholestan, 3,6-bis(4-aminophenoxy)cholestan, 4-(4'-trifluoromethoxybenzoyloxy)cyclohexyl-3,5-diaminobenzoate, 1,1-bis(4-((aminophenyl)methyl)phenyl)-4-butylcyclohexane, 3,5-diaminobenzoic acid =5ξ-cholestan-3-yl, and the following formula (E-1) [Chem. 24] (In formula (E-1), X ^I and X ^II are independently single bonds, -O-, *-COO-, or *-OCO- (where "*" indicates a bond with the diaminophenyl side). ^RI is an alkyldiyl group with 1 to 3 carbon atoms. R ^II is a single bond or an alkyldiyl group with 1 to 3 carbon atoms. R ^III is an alkyl, alkoxy, fluoroalkyl, or fluoroalkoxy group with 1 to 20 carbon atoms. a is 0 or 1. b is an integer from 0 to 3. c is an integer from 0 to 2. d is 0 or 1. Where 1≦a+b+c≦3) The compounds represented are iso-chain diamines, etc.; Diamino organosilicones include 1,3-bis(3-aminopropyl)-tetramethyldisiloxane, etc.

Examples of compounds represented by formula (F-1) include those represented by formulas (F-1-1) to (F-1-3). Examples of compounds represented by formula (E-1) include those represented by formulas (E-1-1) to (E-1-4). Other diamines may be used alone or in combination of two or more. Furthermore, in the formula, "Boc" represents tert-butyloxycarbonyl (hereinafter the same). [Chem. 25]

When polyamide [A] is manufactured by the method described in [2], the proportion of a particular diamine used is preferably 20 mol% or more, more preferably 30 mol% or more, and even more preferably 40 mol% or more, relative to the total amount of diamine compounds used in the synthesis of polyamide [A].

(Synthesis of Polyamide) Polyamide [A] can be obtained by reacting a tetracarboxylic dianhydride and a diamine compound with a molecular weight adjuster, if desired. One preferred method for manufacturing polyamide [A] is to react the tetracarboxylic dianhydride with the diamine compound using a monomer comprising at least one of a specific diamine obtained by method 3A and a specific acid dianhydride obtained by method 2B.

In the synthesis reaction of polyacrylic acid [A], the preferred ratio of tetracarboxylic dianhydride to diamine compound is 0.2 to 2 equivalents of the anhydride group of tetracarboxylic dianhydride relative to the amino group of the diamine compound. Examples of molecular weight adjusters include: maleic anhydride, phthalic anhydride, itaconic anhydride, etc.; monoamine compounds such as aniline, cyclohexylamine, n-butylamine, etc.; and monoisocyanate compounds such as phenyl isocyanate, naphthyl isocyanate, etc. The preferred ratio of the molecular weight adjuster to 20 parts by mass or less, relative to 100 parts by mass of the total tetracarboxylic dianhydride and diamine compound used.

The synthesis of polyamide [A] is preferably carried out in an organic solvent. The preferred reaction temperature is -20°C to 150°C, and the preferred reaction time is 0.1 hours to 24 hours. Examples of organic solvents used in the reaction include: aprotic polar solvents, phenolic solvents, alcoholic solvents, ketone solvents, ester solvents, ether solvents, halogenated hydrocarbons, and hydrocarbons. Among these, it is preferred to use one or more selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, tetramethylurea, hexamethylphosphoric acid triamine, m-cresol, xylenol, and halogenated phenol as the reaction solvent, or to use a mixture of one or more of these solvents with other organic solvents (e.g., butyl solvent, diethylene glycol diethyl ether, etc.). The amount of organic solvent used is preferably set at 0.1% to 50% by mass relative to the total amount of the reaction solution, where the total amount of tetracarboxylic dianhydride and the diamine compound is 0.1% to 50% by mass.

A polymer solution obtained by dissolving polyacrylic acid [A] can be obtained in the manner described above. The polymer solution can be used directly in the preparation of liquid crystal alignment agents, or it can be used in the preparation of liquid crystal alignment agents after separating the polyacrylic acid [A] contained in the polymer solution.

• Polyamide When polymer [A] is a polyamide, the polyamide (hereinafter also referred to as "polyamide [A]") can be obtained, for example, by the following methods: [I] reacting polyamide [A] with an esterifying agent; [II] reacting a tetracarboxylic acid diester with a diamine compound containing a specific diamine; [III] reacting a tetracarboxylic acid diester dihalide with a diamine compound containing a specific diamine. Polyamide [A] may have only an amide structure, or it may be a partial esterification in which both an amide structure and an amide structure coexist. The reaction solution obtained by dissolving polyamide [A] can be directly used in the preparation of liquid crystal alignment agents, or it can be used in the preparation of liquid crystal alignment agents after separating the polyamide [A] contained in the reaction solution.

• Polyimide When polymer [A] is a polyimide, the polyimide (hereinafter also referred to as "polyimide [A]") can be obtained, for example, by dehydrating and cyclizing polyamide [A] synthesized in the manner described above, followed by amide imidization. Polyimide [A] can be a fully amide imidized product formed by completely dehydrating and cyclizing the amide structure of polyamide [A], which is its precursor, or it can be a partially amide imidized product formed by dehydrating and cyclizing only a portion of the amide structure, resulting in the coexistence of the amide structure and the amide ring structure. Polyimide [A] preferably has a amide content of 20% to 99%, more preferably 30% to 90%. Furthermore, the amide content is expressed as a percentage, representing the proportion of the number of amide ring structures to the total number of amide acid structures and amide ring structures in the polyimide. Here, a portion of the amide ring may be an isoamide ring.

The dehydration and ring-closing of polyacrylic acid [A] is preferably carried out by the following method: dissolving polyacrylic acid [A] in an organic solvent, adding a dehydrating agent and a dehydration and ring-closing catalyst to the solution, and heating as needed. In this method, anhydrides such as acetic anhydride, propionic anhydride, and trifluoroacetic anhydride can be used as the dehydrating agent. The amount of dehydrating agent used is preferably set to 0.01 mol to 20 mol relative to 1 mol of the acetic acid structure of polyacrylic acid [A]. Tertiary amines such as pyridine, trimethylpyridine, dimethylpyridine, and triethylamine can be used as the dehydration and ring-closing catalyst. The amount of dehydration ring-closing catalyst used is preferably set to 0.01 mol to 10 mol relative to 1 mol of dehydrating agent. Examples of organic solvents used in the dehydration ring-closing reaction that are used to synthesize polyamide [A] can be listed. The reaction temperature of the dehydration ring-closing reaction is preferably 0°C to 180°C. The reaction time is preferably 1.0 h to 120 h. Furthermore, the reaction solution containing polyimide [A] can be directly used in the preparation of liquid crystal alignment agents, or the polyimide [A] can be separated before being used in the preparation of liquid crystal alignment agents.

When polymer [A] is selected from at least one of the groups consisting of polyamide, polyamide ester, and polyimide, the solution viscosity of polymer [A] is preferably 10 mPa·s to 800 mPa·s when preparing a solution with a concentration of 10% by mass, and more preferably 15 mPa·s to 500 mPa·s. Furthermore, the solution viscosity (mPa·s) is a value obtained by measuring a 10% by mass polymer solution prepared using a good solvent for polymer [A] (e.g., γ-butyrolactone, N-methyl-2-pyrrolidone, etc.) at 25°C using an E-type rotational viscometer.

The weight-average molecular weight (Mw) of polymer [A], as determined by gel permeation chromatography (GPC) based on polystyrene, is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. Furthermore, the molecular weight distribution (Mw/Mn), expressed as the ratio of Mw to the number-average molecular weight (Mn) of polystyrene determined by GPC, is preferably 7 or less, more preferably 5 or less. Moreover, when preparing the liquid crystal alignment agent, polymer [A] can be used alone or in combination with two or more other polymers.

<Other Components> In addition to polymer [A], the liquid crystal alignment agent may also contain components different from polymer [A] (hereinafter referred to as "other components") as needed.

• Polymer [Q] The liquid crystal alignment agent of this invention may further contain a polymer (hereinafter also referred to as "polymer [Q]") that does not have part of structure (a) as a polymer component.

The main framework of polymer [Q] is not particularly limited. Examples of polymer [Q] include: polyamide, polyamide ester, polyimide, polyorganosiloxane, polyester, polyenamine, polyurea, polyamide, polyamide-imide, polybenzoxazole precursor, polybenzoxazole, cellulose derivative, polyacetal, (meth)acrylic polymers, styrene polymers, maleimide polymers, styrene-maleimide copolymers, etc. From the viewpoint of obtaining a highly reliable liquid crystal element, polymer [Q] is preferably selected from at least one of the group consisting of polyamide, polyamide ester, polyimide, polyorganosiloxane, and addition polymers. Examples of addition polymers include: (meth)acrylic polymers, styrene polymers, maleimide polymers, and styrene-maleimide copolymers.

When the liquid crystal alignment agent of the present invention contains both polymer [A] and polymer [Q], the content of polymer [Q] is preferably 1% by mass or more, and more preferably 2% by mass or more, relative to the total amount of polymer [A] and polymer [Q]. Furthermore, the content of polymer [Q] is preferably 95% by mass or less, and more preferably 90% by mass or less, relative to the total amount of polymer [A] and polymer [Q]. Polymer [Q] can be used alone or in combination with two or more polymers.

• Solvent The liquid crystal alignment agent of this invention is prepared as a liquid composition in which the polymer component and other components, if necessary, are preferably dispersed or dissolved in a suitable solvent.

Organic solvents are preferred. Specific examples include: N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 1,2-dimethyl-2-imidazolinone, 1,3-dimethyl-2-imidazolinone, phenol, γ-butyrolactone, γ-butyrolactam, N,N-dimethylformamide, N,N-dimethylacetamide, 4-hydroxy-4-methyl-2-pentanone, diacetone alcohol, 1-hexanol, 2-hexanol, propane-1,2-diol, 3-methoxy-1-butanol, ethylene glycol monomethyl ether, methyl lactate, ethyl lactate, butyl lactate, methyl acetate, ethyl acetate, butyl acetate, and acetoacetic acid. Methyl acetate, ethyl propionate, methyl methoxypropionate, ethyl ethoxypropionate, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-isopropyl ether, ethylene glycol-n-butyl ether (butyl solvent), 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, diisoamyl ether, ethylene carbonate, propylene carbonate, propylene glycol monomethyl ether (propylene) Diethylene glycol monomethyl ether (PGME), diethylene glycol diethyl ether acetate, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol diacetate, cyclopentanone, cyclohexanone, etc. As solvents, one or more can be used alone or in combination.

Other components contained in the liquid crystal alignment agent, besides those mentioned above, may include, for example, crosslinking agents, antioxidants, metal chelate compounds, curing accelerators, surfactants, fillers, dispersants, and photosensitizers. The formulation ratios of other components can be selected appropriately according to each compound without compromising the effectiveness of the invention.

The solid content concentration in the liquid crystal alignment agent (the proportion of the total mass of components other than the solvent in the liquid crystal alignment agent to the total mass of the liquid crystal alignment agent) should be appropriately selected considering factors such as viscosity and volatility, and is preferably in the range of 1% to 10% by mass. If the solid content concentration is 1% by mass or more, the film thickness of the coating can be sufficiently ensured, and a liquid crystal alignment film exhibiting better liquid crystal alignment can be obtained, which is preferable in this respect. On the other hand, if the solid content concentration is 10% by mass or less, there is a tendency that the coating can be set to an appropriate thickness, a liquid crystal alignment film exhibiting good liquid crystal alignment can be easily obtained, and the viscosity of the liquid crystal alignment agent becomes appropriate, resulting in good coatability.

According to the present invention described above, a liquid crystal alignment agent as shown below is provided. <1> A liquid crystal alignment agent comprising a polymer [A] having a partial structure (a) represented by formula (1) on a main chain. <2> The liquid crystal alignment agent according to <1>, wherein the polymer [A] comprises a structural unit derived from a diamine having said partial structure (a). <3> The liquid crystal alignment agent according to <2>, wherein the diamine is a compound represented by formula (2). <4> The liquid crystal alignment agent according to any one of <1> to <3>, wherein the polymer [A] comprises a structural unit derived from a tetracarboxylic acid derivative having said partial structure (a). <5> The liquid crystal alignment agent according to <4>, wherein the tetracarboxylic acid derivative is at least one selected from the group consisting of compounds represented by formula (3) and compounds represented by formula (4). <6> The liquid crystal alignment agent according to any one of <1> to <5>, wherein the polymer [A] is at least one selected from the group consisting of polyamide, polyamide ester, and polyimide. <7> The liquid crystal alignment agent according to any one of <1> to <6>, wherein the polymer [A] comprises a structural unit derived from an alicyclic tetracarboxylic acid dianhydride. <8> The liquid crystal alignment agent according to any one of <1> to <7> further comprises a polymer [Q] that does not have the partial structure (a).

《Liquid Crystal Alignment Film and Liquid Crystal Element》 The liquid crystal alignment film of this invention can be manufactured using a liquid crystal alignment agent prepared in the manner described above. Furthermore, the liquid crystal element of this invention includes a liquid crystal alignment film formed using the liquid crystal alignment agent described above. The driving method of the liquid crystal in the liquid crystal element is not particularly limited, and can be applied to various modes such as TN type, STN type, VA type (including VA-MVA type, VA-Patterned Vertical Alignment (PVA) type, IPS type, FFS type, Optically Compensated Bend (OCB) type, Polymer Sustained Alignment (PSA) type, etc. The liquid crystal element can be manufactured, for example, by a method including the following steps 1 to 3. The substrate used in step 1 varies depending on the desired operating mode. Steps 2 and 3 are common across all action modes.

<Step 1: Coating Formation> First, a coating is formed on the substrate by coating a liquid crystal alignment agent onto the substrate, preferably by heating the coated surface. As the substrate, examples include: float glass, sodium glass, and other glass; transparent substrates containing plastics such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polycarbonate, and poly(alicyclic olefins). As a transparent conductive film disposed on one side of the substrate, NESA film (a registered trademark of PPG Industries, Inc.) containing tin oxide ( _SnO₂ ) or indium tin oxide ( _ITO ) film containing indium oxide-tin oxide ( _In₂O₃ - _SnO₂ ) can be used. In manufacturing TN, STN, or VA type liquid crystal elements, two substrates with patterned transparent conductive films are used. On the other hand, in manufacturing IPS or FFS type liquid crystal elements, a substrate with patterned comb-shaped electrodes and an opposing substrate without electrodes are used.

There are no particular limitations on the method of applying liquid crystal alignment agent to the substrate. The application of liquid crystal alignment agent to the substrate can be performed by, for example, spin coating, printing (e.g., offset printing, flexographic printing), inkjet printing, slotted coating, rod coating, extrusion die coating, direct gravure coating, chamber doctor coating, offset gravure coating, impregnation coating, MB coating, etc.

After coating the liquid crystal alignment agent, preheating (pre-baking) is preferably performed to prevent sagging of the coated liquid crystal alignment agent. The pre-baking temperature is preferably 30°C to 200°C, and the pre-baking time is preferably 0.25 minutes to 10 minutes. Then, the solvent is completely removed, and a calcination (post-baking) step is performed as needed for the purpose of thermally imidizing the acetic acid structures present in the polymer. The calcination temperature (post-baking temperature) is preferably 80°C to 280°C, more preferably 80°C to 250°C. The post-baking time is preferably 5 minutes to 200 minutes. The film thickness of the formed film is preferably 0.001 μm to 1 μm.

<Step 2: Alignment Treatment> In manufacturing TN, STN, IPS, or FFS type liquid crystal elements, an alignment treatment is performed to impart liquid crystal alignment capability to the coating formed in Step 1 (alignment treatment). This imparts the alignment capability of the liquid crystal molecules to the coating, forming a liquid crystal alignment film. Preferably, the alignment treatment involves rubbing the surface of the coating formed on the substrate with cotton or nylon, or photoalignment treatment by irradiating the coating with light to impart liquid crystal alignment capability. In manufacturing vertically aligned liquid crystal elements, the coating formed in Step 1 can be used directly as a liquid crystal alignment film; however, alignment treatment can also be performed on the coating to further improve the liquid crystal alignment capability.

Irradiation for photoalignment can be performed by methods such as: irradiating a coating after a post-baking step; irradiating a coating after a pre-baking step and before a post-baking step; or irradiating the coating during heating in at least one of the pre-baking or post-baking steps. The radiation irradiating the coating can be, for example, ultraviolet light or visible light with wavelengths from 150 nm to 800 nm. Ultraviolet light with wavelengths from 200 nm to 400 nm is preferred. When the radiation is polarized, it can be linearly polarized or partially polarized. When the radiation used is linearly polarized or partially polarized, irradiation can be performed from a direction perpendicular to the substrate surface, from an oblique direction, or a combination of these directions. When irradiating unpolarized light, the irradiation direction is set to an oblique direction.

Examples of light sources used include: low-pressure mercury lamps, high-pressure mercury lamps, deuterium lamps, metal halide lamps, argon resonant lamps, xenon lamps, and excimer lasers. The radiation dose is preferably 200 J/ ^m² to 30,000 J/ ^m² , more preferably 500 J/ ^m² to 10,000 J/ ^m² . After irradiation to impart alignment capability, the substrate surface may be cleaned using, for example, water, an organic solvent (e.g., methanol, isopropanol, 1-methoxy-2-propanol acetate, butyl solvent, ethyl lactate, etc.), or a mixture thereof, or the substrate may be heated.

<Step 3: Construction of Liquid Crystal Cells> Prepare two substrates with liquid crystal alignment films formed as described above. A liquid crystal cell is manufactured by placing liquid crystal between the two opposing substrates. Methods for manufacturing liquid crystal cells include: arranging two substrates facing each other with the liquid crystal alignment films facing each other and a gap between them; bonding the peripheries of the two substrates together using a sealant; injecting liquid crystal into the cell gap surrounded by the substrate surfaces and the sealant and sealing the injection hole; and using a liquid crystal drop filling (ODF) method. For example, an epoxy resin containing a hardener and alumina spheres as spacers can be used as a sealant. For the liquid crystal, nematic liquid crystals and smectic liquid crystals can be used, with nematic liquid crystals being preferred.

In the PSA mode, the following process is performed: a polymeric compound (e.g., a polyfunctional (meth)acrylate compound) is filled into the intercellular spaces along with the liquid crystal, and after the liquid crystal cells are constructed, the liquid crystal cells are irradiated with light while a voltage is applied between the conductive films of a pair of substrates. When manufacturing a PSA mode liquid crystal element, the proportion of the polymeric compound used is 0.01 to 3 parts by mass relative to 100 parts by mass of the total liquid crystal, preferably 0.1 to 1 part by mass.

In the manufacture of a liquid crystal display device, a polarizing plate is then attached to the outer surface of the liquid crystal cell. Examples of polarizing plates include: a polarizing plate made by clamping a polarizing film called an "H-film" (one side of which is extended and aligned with polyvinyl alcohol and the other side absorbs iodine) with a cellulose acetate protective film, or a polarizing plate containing the H-film itself.

The liquid crystal element of this invention can be effectively applied to a variety of uses. Specifically, it can be used in various display devices such as clocks, portable game consoles, word processors, notebook computers, car navigation systems, camcorders, personal digital assistants (PDAs), digital cameras, mobile phones, smartphones, various surveillance cameras, LCD televisions, information displays, and dimming devices, as well as phase retardation films. [Examples]

The following description of the embodiments is based on examples, but the invention is not to be construed as limited by the following embodiments.

In the following examples, the amide content of the polyimide in the polymer solution is determined by the following method. The required amounts of the starting material compounds and polymers used in the following embodiments are ensured by repeatedly performing the synthesis at the scale shown in the following synthesis examples as needed.

[Imidification rate of polyimide] The polyimide solution was added to pure water, and the resulting precipitate was thoroughly dried under reduced pressure at room temperature. It was then dissolved in dimethyl deuteride and measured by ^1H nuclear magnetic resonance (NMR) at room temperature using tetramethylsilane as a reference material. The amideification rate [%] was calculated from the obtained ^1H -NMR spectrum using the following formula (1). The amide content [%] = (1 - ( ^A1 / ( ^A2 × α))) × 100 ··· (1) (In formula (1), ^A1 is the peak area of protons originating from NH groups that appear near the chemical shift of 10 ppm, ^A2 is the peak area of protons originating from other protons, and α is the proportion of other protons relative to the number of protons of NH groups in the polymer precursor (polyamide))

The abbreviation of the compound is as described below. Furthermore, the compound represented by formula (X) will sometimes be simply referred to as "compound (X)".

(Tetracarboxylic acid dianhydride) [Chem. 26] [Chemistry 27]

(Diamine compound) [Chem. 28] [Chemistry 29] [Chemistry 30]

[Chemistry 31] [Chemistry 32]

(Other compounds) [Chem. 33] [Chemistry 34]

<Synthesis of Monomers> 1. Synthesis of Compounds (DA-1), (DA-8), and (DA-9) Compounds (DA-1), (DA-8), and (DA-9) were synthesized using a method similar to that described in Japanese Patent No. 6013823. The formulation for compound (DA-1) is shown below.

Synthesis of Compound (DA-1): 30 g (0.2 mol) of 4-(2-methylamino-ethyl)-phenylamine and 200 ml of tetrahydrofuran were added to a reaction vessel. Under ice bath cooling, a solution obtained by dissolving 20 g (0.2 mol) of maleic anhydride in 30 ml of tetrahydrofuran was added dropwise, and the mixture was stirred overnight at room temperature. After the reaction was complete, the precipitated solid was filtered, washed three times with 20 ml of tetrahydrofuran, and dried at 60°C for 3 hours to obtain a brown solid. Next, 30 g (0.2 mol) of 4-(2-methylamino-ethyl)-phenylamine, 0.5 g of dimethylaminopyridine, and 100 ml of dimethylformamide were added to the reaction vessel containing the obtained solid. Under ice bath cooling, 38 g (0.2 mol) of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride was added, and the mixture was stirred overnight at room temperature. After the reaction was complete, 300 ml of water was added, and the mixture was extracted three times with 300 ml of ethyl acetate. After drying with sodium sulfate, the solvent was removed by distillation, yielding 28 g of a brown, viscous solid. 80 ml of methanol was added to the obtained solid, and the insoluble solid was filtered off, thus yielding 20 g of compound (DA-1) as a brown solid. The ^1H -NMR determination results of compound (DA-1) are as follows. ¹ H-NMR (300 MHz, DMSO-d ⁶ ) δppm: 7.02 (4H, d), 6.53 (4H, d), 6.44 (2H, s), 3.22-3.57 (10H, m), 2.62 (4H, t).

2. Synthesis of Compounds (DA-2) to (DA-7) Compounds (DA-2) to (DA-7) were first synthesized by referring to the method described in the reference (Journal of Polymer Science: Polymer Chemistry Edition, 1975, Vol. 13, 1691-1698), using compounds (D-1) to (D-4) as intermediates. The formulation for compound (DA-2) is shown below. Furthermore, compounds (DA-2) to (DA-7) are cis compounds.

Synthesis of Compound (DA-2): 19.6 g (0.2 mol) of maleic anhydride and 100 ml of acetic acid were added to a reaction vessel. A solution obtained by dissolving 5.0 g (0.1 mol) of hydrazine monohydrate in 25 ml of acetic acid was added dropwise. During the dropwise addition, an ice bath was used to control the reaction temperature so that the reaction solution did not reach above 25°C. After the dropwise addition was completed, the mixture was allowed to stand for 3 hours, and the precipitate was filtered and washed three times with 30 ml of ethanol. Then, it was dried at 60°C for 5 hours to obtain 21 g of a pale yellow solid. The obtained solid was transferred to a reaction vessel, and 110 ml of thionyl chloride was added. The mixture was stirred at 75°C for 6 hours. After the reaction, the mixture was cooled to room temperature, and the precipitate was filtered. The precipitate was washed with hexane and dried at 60°C for 5 hours to obtain 10 g (0.05 mol) of compound (D-1). Compound (D-1) was dissolved in 50 ml of N-methyl-2-pyrrolidone, and 14 g (0.1 mol) of 2-(4-aminophenyl)ethylamine was added dropwise over 30 minutes. After the addition, the mixture was stirred at room temperature for 1 hour, and the reaction solution was added to 500 ml of water to obtain a precipitate. The precipitate was filtered, washed with water, and dried at 60°C for 5 hours to obtain 20 g of compound (DA-2). The ^1H -NMR determination of compound (DA-2) is as follows. ¹ H-NMR (300 MHz, DMSO-d ⁶ ) δppm: 8.96 (2H, s), 6.89 (4H, m), 6.51 (4H, m), 6.19-6.31 (4H, m), 3.29 (4H, m), 2.60 (4H, m).

3. Synthesis of Compound (DA-10): 13.9 g (0.1 mol) of 2-amino-5-nitropyridine, 7.9 g (0.1 mol) of pyridine, and 50 ml of tetrahydrofuran were added to a reaction vessel. A solution obtained by dissolving 7.6 g (0.05 mol) of fumarate chloride in 25 ml of tetrahydrofuran was added dropwise. After the addition was complete, the mixture was stirred at room temperature for 8 hours. The resulting reaction solution was injected into water, and the precipitate was filtered. The resulting solid was washed with water and ethanol, and dried at 60°C for 5 hours to obtain 14.5 g of an intermediate as a brown solid. The obtained intermediate was transferred to a reaction vessel, and 10 wt% palladium/carbon (2 g) and N,N-dimethylformamide (30 ml) were added. The mixture was heated at 50 °C for 8 hours under a hydrogen atmosphere. After filtering the reaction solution to remove the catalyst, the filtrate was injected into ice water, and the resulting precipitate was filtered and recovered. The resulting solid was washed with ethanol and dried at 60 °C for 5 hours to obtain 12.2 g of compound (DA-10). The ^1H -NMR determination results of compound (DA-10) are as follows: ^1H -NMR (300 MHz, DMSO- ^d⁶ ) δppm: 11.2 (2H, s), 7.13–7.44 (6H, m), 6.18 (2H, s).

4. Synthesis of Compound (DA-12) Compound (DA-12) was synthesized using the same method as that used for compound (DA-10), except that 4-nitroaniline was used instead of 2-amino-5-nitropyridine as the starting material.

5. Synthesis of Compound (DA-11): 13.9 g (0.1 mol) of 2-amino-5-nitropyridine, 7.9 g (0.1 mol) of pyridine, and 50 ml of tetrahydrofuran were added to a reaction vessel. A solution obtained by dissolving 7.6 g (0.05 mol) of fumarate chloride in 25 ml of tetrahydrofuran was added dropwise. After the addition was complete, the mixture was stirred at room temperature for 8 hours. The resulting reaction solution was poured into water, and the precipitate was filtered. The resulting solid was washed with water and ethanol, and dried at 60°C for 5 hours to obtain 14.5 g of an intermediate as a brown solid. The obtained intermediate was transferred to a reaction vessel, and 25 ml of dimethylformamide was added. 18 g (0.08 mmol) of di-tert-butyl dicarbonate was added, and the mixture was stirred at room temperature for 16 hours. The reaction solution was added dropwise to water, the precipitate was filtered, washed with water, and dried at 60°C for 3 hours to obtain 13.2 g of a light brown solid. The obtained solid was transferred to a reaction vessel, and 10 wt% palladium/carbon (1.8 g) and N,N-dimethylformamide (30 ml) were added. The mixture was heated at 50°C for 8 hours under a hydrogen atmosphere. After filtering the reaction solution and removing the catalyst, the filtrate was injected into ice water, and the resulting precipitate was filtered and recovered. The obtained solid was washed with ethanol and dried at 60°C for 5 hours to obtain 9.8 g of compound (DA-11). ^{The 1H} -NMR determination results of compound (DA-11) are as follows: ^1H -NMR (300 MHz, DMSO- ^d6 ) δppm: 8.09 (2H, m), 7.28-7.44 (4H, m), 6.93 (2H, s), 1.39 (18H, s).

6. Synthesis of Compound (DA-13) Compound (DA-13) was synthesized using the same method as that used for (DA-11), except that 4-nitroaniline was used instead of 2-amino-5-nitropyridine as the starting material.

7. Synthesis of Compound (TA-1) 11.5 g (0.1 mol) of 3-aminodihydrofuran-2,5-dione, 7.9 g (0.1 mol) of pyridine, and 300 ml of tetrahydrofuran were added to a reaction vessel. The reaction solution was brought to 0°C using an ice bath, and a solution obtained by dissolving 7.6 g (0.05 mol) of fumarate chloride in 50 ml of tetrahydrofuran was added dropwise. After the addition was complete, the mixture was stirred at room temperature for 4 hours. After the reaction, the solvent was removed under reduced pressure. Then, 50 g of acetic acid and 50 g of acetic anhydride were added, and the mixture was stirred at 100°C for 3 hours. The resulting precipitate was filtered, washed with acetic acid and n-hexane, and dried under reduced pressure at 60°C for 5 hours to obtain compound (TA-1).

8. Synthesis of Compound (TA-2) Compound (TA-2) was synthesized using the same method as that used for compound (TA-1), except that 5-hydroxyisobenzofuran-1,3-dione was used instead of 3-aminodihydrofuran-2,5-dione as the starting material.

9. Synthesis of Compound (TA-3) 19.6 g (0.2 mol) of maleic anhydride and 100 ml of acetic acid were added to a reaction vessel. A solution obtained by dissolving 5.0 g (0.1 mol) of hydrazine monohydrate in 25 ml of acetic acid was added dropwise. During the dropwise addition, an ice bath was used to control the reaction temperature so that the reaction solution did not reach above 25°C. After the dropwise addition was completed, the mixture was allowed to stand for 3 hours, and the precipitate was filtered and washed three times with 30 ml of ethanol. Then, it was dried at 60°C for 5 hours to obtain 21 g of a pale yellow solid. The obtained solid was transferred to a reaction vessel, and 110 ml of thionyl chloride was added. The mixture was stirred at 75°C for 6 hours. After the reaction, the mixture was cooled to room temperature, and the precipitate was filtered. The precipitate was washed with hexane and dried at 60°C for 5 hours to obtain 10 g (0.05 mol) of compound (D-1). Compound (D-1) was dissolved in 50 ml of N-methyl-2-pyrrolidone, and 11.5 g (0.1 mol) of 3-aminodihydrofuran-2,5-dione was added dropwise over 30 minutes. After the addition was complete, the mixture was stirred at room temperature for 4 hours. Following the reaction, the solvent was removed under reduced pressure. Then, 50 g of acetic acid and 50 g of acetic anhydride were added, and the mixture was stirred at 100°C for 3 hours. The resulting precipitate was filtered, washed with acetic acid and n-hexane, and dried at 60°C under reduced pressure for 5 hours to obtain compound (TA-3). Furthermore, compound (TA-3) is the cis form.

<Polymer Synthesis> 1. Synthesis of Polyamide [Synthesis Example 1] 100 moles of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (compound (TB-1)) as a tetracarboxylic dianhydride and 100 moles of compound (DA-2) as a diamine compound were dissolved in N-methyl-2-pyrrolidone (NMP). The reaction was carried out at room temperature for 6 hours to obtain a solution containing 15% by mass of polyamide (referred to as polymer (PAA-1)).

Furthermore, polymer (PAA-1) can also be obtained by polymerizing compound (D-1) as an intermediate without using the separated compound (DA-2). Different synthetic methods for polymer (PAA-1) are shown below. [Other Synthetic Methods of PAA-1] 100 moles of compound (D-1) were dissolved in N-methyl-2-pyrrolidone, and 200 moles of 2-(4-aminophenyl)ethylamine were added dropwise over 30 minutes. After the addition, the mixture was stirred at room temperature for 1 hour. Then, 100 moles of 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride as a tetracarboxylic acid dianhydride were added, and the reaction was carried out at room temperature for 6 hours to obtain a solution containing 15% by mass of polymer (PAA-1).

[Synthesis Examples 2 to 24] Except for changing the types and amounts of tetracarboxylic dianhydrides and diamine compounds used as described in Table 1, the same procedures as in Synthesis Example 1 were performed to obtain polyamides (polymers (PAA-2) to (PAA-20) and polymers (paa-1) to (paa-4)). Furthermore, in Table 1, the values for tetracarboxylic dianhydrides (dianhydride 1, dianhydride 2) represent the proportion (molar ratio) of each compound relative to 100 moles of the total amount of tetracarboxylic dianhydrides used in the synthesis of polyamides. The values for diamine compounds (diamine 1 to diamine 3) represent the proportion (molar ratio) of each compound relative to 100 moles of the total amount of diamine compounds used in the synthesis of polyamides.

[Table 1] Polymer name Acid dianhydride 1 acid dianhydride 2 acid dianhydride 3 Diamine 1 Diamine 2 Diamine 3 Kind Mörby Kind Mörby Kind Mörby Kind Mörby Kind Mörby Kind Mörby Synthesis example 1 PAA-1 TB-1 100 DA-2 100 Synthesis example 2 PAA-2 TB-1 60 TB-4 40 DA-1 60 DB-1 40 Synthesis example 3 PAA-3 TB-1 60 TB-3 40 DA-2 20 DB-2 60 DB-3 20 Synthesis example 4 PAA-4 TB-1 100 DA-3 50 DB-4 50 Synthesis example 5 PAA-5 TB-3 100 DA-4 50 DB-5 50 Synthesis example 6 PAA-6 TB-3 60 TB-4 40 DA-5 100 Synthesis Example 7 PAA-7 TB-3 60 TB-4 40 DA-6 100 Synthesis example 8 PAA-8 TB-1 60 TB-4 40 DA-7 100 Synthesis example 9 PAA-9 TB-2 100 DA-8 20 DB-6 50 DB-7 30 Synthesis example 10 PAA-10 TB-1 100 DA-9 50 DB-8 50 Synthesis Example 11 PAA-11 TA-1 100 DB-2 50 DB-3 50 Synthesis example 12 PAA-12 TA-2 50 TB-1 50 DB-4 100 Synthesis example 13 PAA-13 TA-3 100 DB-5 100 Synthesis Example 14 PAA-14 TB-1 80 TB-3 20 DA-2 50 DB-9 30 DB-11 20 Synthesis Example 15 PAA-15 TB-2 100 DA-2 10 DB-10 50 DB-12 40 Synthesis Example 16 PAA-16 TB-1 50 TB-3 50 DA-2 20 DB-13 70 DB-14 10 Synthesis Example 17 PAA-17 TB-2 50 TB-3 50 DA-10 50 DB-12 40 DB-14 10 Synthesis example 18 PAA-18 TB-2 100 DA-11 50 DB-12 50 Synthesis example 19 PAA-19 TB-2 50 TB-4 50 DA-12 50 DB-8 20 DB-12 30 Synthesis example 20 PAA-20 TB-2 100 DA-13 30 DB-10 50 DB-12 20 Synthesis Example 21 paa-1 TB-1 100 DB-3 100 Synthesis example 22 paa-2 TB-1 100 DB-13 40 DB-11 60 Synthesis example 23 paa-3 TB-1 100 DB-13 50 DB-14 50 Synthesis example 24 paa-4 TB-2 100 DB-10 50 DB-12 50

2. Synthesis of Polyimide [Synthesis Example 25] 60 moles of compound (TB-1) as a tetracarboxylic dianhydride and 40 moles of compound (TB-3), 20 moles of compound (DA-2) as a diamine compound, 60 moles of compound (DB-2) and 20 moles of compound (DB-3) were dissolved in NMP and reacted at room temperature for 6 hours to obtain a solution containing 15% by mass of polyamide. Then, NMP was added to the obtained polyamide solution to prepare a solution with a polyamide concentration of 10% by mass. Pyridine and acetic anhydride were added, and a dehydration and ring-closing reaction was carried out at 60°C for 4 hours. Following the dehydration and ring-closing reaction, the solvent in the system was replaced using fresh NMP, thereby obtaining a solution containing 15% by mass of polyimide (designated as polymer (PI-1)) with an imidization rate of approximately 80%.

[Synthesis Examples 26-30] Except for changing the types and amounts of tetracarboxylic dianhydrides and diamine compounds used as described in Table 2, the same procedures as in Synthesis Example 25 were performed to obtain polyimides (polymers (PI-2) to (PI-3) and polymers (pi-1) to (pi-3)). Furthermore, in Table 2, the values for tetracarboxylic dianhydrides (dianhydride 1 to dianhydride 3) represent the proportion (molar ratio) of each compound relative to 100 moles of the total amount of tetracarboxylic dianhydrides used in the synthesis of polyimides. The values for diamine compounds (diamine 1 to diamine 4) represent the proportion (molar ratio) of each compound relative to 100 moles of the total amount of diamine compounds used in the synthesis of polyimides.

[Table 2] Polymer name Acid dianhydride 1 acid dianhydride 2 acid dianhydride 3 Diamine 1 Diamine 2 Diamine 3 Diamine 4 Kind Mörby Kind Mörby Kind Mörby Kind Mörby Kind Mörby Kind Mörby Kind Mörby Synthesis example 25 PI-1 TB-1 60 TB-3 40 DA-2 20 DB-2 60 DB-3 20 Synthesis Example 26 PI-2 TB-2 100 DA-2 10 DB-10 50 DB-12 40 Synthesis Example 27 PI-3 TB-3 100 DA-2 15 DB-15 20 DB-16 35 DB-17 30 Synthesis example 28 pi-1 TB-1 100 DB-3 100 Synthesis Example 29 pi-2 TB-2 100 DB-10 50 DB-12 50 Synthesis example 30 pi-3 TB-3 100 DB-15 20 DB-16 50 DB-17 30

3. Synthesis of Polyorganosiloxanes [Synthesis Example 31] 100.0 g of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (compound (s-1)), 500 g of methyl isobutyl ketone, and 10.0 g of triethylamine were added to a 1000 ml three-necked flask and mixed at room temperature. Then, 100 g of deionized water was added dropwise over 30 minutes using a self-dropping funnel, and the mixture was refluxed and reacted at 80°C for 6 hours. After the reaction was complete, the organic layer was removed and washed with a 0.2% ammonium nitrate aqueous solution until the water was neutral. The solvent and water were then removed by distillation under reduced pressure. A suitable amount of methyl isobutyl ketone was added to obtain a 50% by mass solution of a polymer (ESSQ-1) as an epoxy-containing polyorganosiloxane. To a 500 ml three-necked flask, 3.10 g of compound (c-1) (representing 20 mol% of the epoxy content of polymer (ESSQ-1), 3.24 g of compound (c-2) (representing 10 mol% of the epoxy content of polymer (ESSQ-1), 1.00 g of tetrabutylammonium bromide, 20.0 g of the solution containing polymer (ESSQ-1), and 290.0 g of methyl isobutyl ketone were added, and the mixture was stirred at 90°C for 18 hours. After cooling to room temperature, the separation and washing operation was repeated 10 times using distilled water. Then, the organic layer is recovered. After repeating the concentration and NMP dilution process twice using a rotary evaporator, an NMP solution of polyorganosiloxane (designated as polymer (PSQ-1)) is obtained by adjusting the NMP concentration to 10% by mass using NMP.

4. Synthesis of Styrene-Malaysianimide Copolymers [Synthesis Example 32] Under nitrogen, 5.00 g of compound (M-1), 1.05 g of compound (M-2), 4.80 g of compound (M-3), and 2.26 g of compound (M-4) as monomers, 0.39 g of 2,2'-azobis(2,4-dimethylpentanilide) as a free radical polymerization initiator, 0.39 g of 2,4-diphenyl-4-methyl-1-pentene as a chain transfer agent, and 52.5 ml of N-methyl-2-pyrrolidone (NMP) as a solvent were added to a 100 mL two-necked flask, and polymerization was carried out at 70 °C for 6 hours. After reprecipitation in methanol, the precipitate was filtered and vacuum-dried at room temperature for 8 hours to obtain the target polymer (designated as polymer (MI-1)).

5. Synthesis of Polyamide [Synthesis Example 33] The polyamide was synthesized according to the method described in the reference (Journal of Polymer Science: Polymer Chemistry Edition, 1975, Vol. 13, 1691-1698). 100 moles of compound (D-1) as a diisomaleimide and 100 moles of compound (DB-18) as a diamine were dissolved in N-methyl-2-pyrrolidone (NMP), and the reaction was carried out at room temperature for 6 hours to obtain a solution containing 15% by mass of polyamide (referred to as polymer (pa-1)).

<Evaluation as a Polymer> [Example 1: Evaluation of Residual Amine and Storage Stability] 1. Evaluation of Residual Amine A solution of the polymer (PAA-1) obtained in Synthesis Example 1 was added dropwise to acetone to precipitate the polymer. A portion of the supernatant was collected and evaluated by liquid chromatography (LC). A peak of the diamine used as a starting material was observed and marked as "present," while no peak was observed and marked as "absent." As a result, the residual amine peak in Example 1 was "absent."

2. Evaluation of Storage Stability Regarding the polymer (PAA-1) solution obtained in Synthesis Example 1, storage stability was evaluated by the change in viscosity D1 immediately after preparation and D2 after storage at room temperature for 7 days ([(D2-D1)/D1)]×100 (%)). A viscosity change of 5% or more was rated as "poor (×)", and a change of less than 5% was rated as "good (○)". Therefore, the storage stability in Example 1 was rated as "good (○)".

[Reference Example 1] Except for the changes to the polymer as shown in Table 3, the residual amine and storage stability were evaluated in the same manner as in Example 1. The results are shown in Table 3. [Table 3] Polymer types Residual amines Maintain stability Implementation Example 1 PAA-1 without ○ Reference Example 1 pa-1 have ×

As shown in Table 3, polymer (PAA-1) has less residual amine compared to polymer (pa-1) which is a polyamide, and it also exhibits good stability when stored in solution.

<Preparation and Evaluation of Liquid Crystal Orienting Agent> [Example 2: Triboelectric FFS Type Liquid Crystal Display Element] 1. Preparation of Liquid Crystal Orienting Agent Using a solution of the polymer (PAA-2) obtained in Synthesis Example 2, a solution with a solvent composition of NMP/BC = 80/20 (mass ratio) and a solid content of 3.5% by mass was prepared by diluting the solution with NMP and butyl cellosolve (BC). The solution was then filtered using a 0.2 μm sieve to prepare the liquid crystal alignment agent (AL-1).

2. Fabrication of an FFS-type Liquid Crystal Display Element Using a Triboelectric Method A glass substrate (designated as the first substrate) on which planar electrodes (bottom electrodes), an insulating layer, and comb-shaped electrodes (top electrodes) are sequentially stacked on a single side, and a glass substrate without electrodes (designated as the second substrate) is prepared. Then, a liquid crystal alignment agent (AL-1) is coated onto the electrode forming surface of the first substrate and a single side of the second substrate using a rotary device, and pre-baked at 110°C for 3 minutes. Finally, it is dried in a 230°C oven with nitrogen replacement in the cavity for 30 minutes (post-baking) to form a coating with an average film thickness of 0.08 μm. Next, the coating surface was rubbed using a friction machine with rollers wound with rayon fabric at a roller speed of 1000 rpm, a stage movement speed of 3 cm/s, and a bristle indentation length of 0.3 mm. Then, it was ultrasonically cleaned in ultrapure water for 1 minute, followed by drying in a clean oven at 100°C for 10 minutes, thereby obtaining a pair of substrates with a liquid crystal alignment film. Subsequently, for the pair of substrates with the liquid crystal alignment film, an epoxy resin adhesive containing 3.5 μm diameter alumina spheres was screen-printed onto the residual liquid crystal injection port at the edge of the surface where the liquid crystal alignment film was formed. Then, the substrates are overlapped and pressed together, and the adhesive is thermosetting at 150°C for 1 hour. Next, negative liquid crystal (Merck, MLC-6608) is filled into the gap between the two substrates through the liquid crystal injection port, and then the liquid crystal injection port is sealed with an epoxy adhesive. Furthermore, to eliminate flow alignment issues during liquid crystal injection, it is heated at 120°C and then slowly cooled to room temperature, thereby manufacturing a liquid crystal cell. Moreover, when the two substrates are overlapped, the friction method of each substrate is antiparallel.

3. Evaluation of Liquid Crystal Orientation: The liquid crystal cells manufactured in step 2. were placed on a high-brightness backlight of 27,000 cd/ ^m² for 500 hours. The liquid crystal orientation was evaluated based on the rate of change of delay before and after backlight illumination. First, for the liquid crystal display element manufactured in step 2., the delay was measured using an Axoscan manufactured by Opto Science. The rate of change of delay α before and after backlight illumination was calculated using the following formula (z-1). It can be said that the smaller the rate of change α, the better the liquid crystal orientation. A rate of change α of less than 1% was set as "good (○)", a rate of change greater than 1% and less than 2% was set as "acceptable (△)", and a rate of change greater than 2% was set as "poor (×)". α = Δθ/θ1 ···（z-1） (In formula (z-1), Δθ represents the delay difference before and after irradiation, and θ1 represents the delay value before irradiation) As a result, the liquid crystal alignment of the embodiment is evaluated as “good (○)”.

4. Evaluation of Initial VHR After placing the liquid crystal cell manufactured in step 2. in an oven at 60°C, the voltage retention rate (VHR) was measured using a VHR measuring device "VHR-1" manufactured by Toyo Technica Co., Ltd., at 1 V and 1670 msec. As an evaluation criterion, a VHR higher than 70% was designated as "Good (○)", a VHR between 60% and 70% was designated as "Acceptable (△)", and a VHR lower than 60% was designated as "Poor (×)". As a result, the initial VHR of the embodiment was evaluated as "Good (○)".

5. Evaluation of VHR Reliability For the liquid crystal cell manufactured in section 2, reliability was evaluated using voltage retention rate (VHR reliability). The evaluation was conducted as follows: First, after applying a 1 V voltage to the liquid crystal cell for 60 microseconds, the voltage retention rate (VHR1) was measured 1670 milliseconds after the application was removed. Next, the liquid crystal cell was irradiated with a cold cathode fluorescent lamp (CCFL) (backlight) at 60°C for one week, and then allowed to cool naturally to room temperature. After cooling, after applying a 1 V voltage to the liquid crystal cell for 60 microseconds, the voltage retention rate (VHR2) was measured 1670 milliseconds after the application was removed. Furthermore, the measuring device used is the VHR-1 VHR measuring device manufactured by Toyo Technica. The rate of change of VHR (ΔVHR) is calculated based on the difference between VHR1 and VHR2 (ΔVHR = VHR1 - VHR2), and VHR reliability is evaluated based on ΔVHR. A ΔVHR less than 15% is classified as "Good (○)", a ΔVHR between 15% and 20% is classified as "Acceptable (△)", and a ΔVHR greater than 20% is classified as "Poor (×)". As a result, the VHR reliability in this embodiment is "Good (○)".

6. Evaluation of Film Strength (Abrasion Resistance) The liquid crystal alignment agent (AL-1) prepared in step 1 was coated onto a glass substrate using a rotary tool and pre-baked at 110°C for 3 minutes. Then, it was dried in a 230°C oven with nitrogen replacement in the chamber for 30 minutes (post-baking) to form a coating with an average thickness of 0.08 μm. The haze value of the coating was measured using a haze meter. Subsequently, the coating was subjected to five abrasion treatments using a friction machine with rollers wound with cotton cloth, at a roller speed of 1000 rpm, a stage movement speed of 3 cm/s, and a cloth indentation length of 0.3 mm. Then, the haze value of the liquid crystal alignment film was measured using a haze meter, and the difference between the haze value and the haze value before the rubbing treatment (haze change value) was calculated. With the haze value of the film before rubbing treatment set to Hz1 (%) and the haze value of the film after rubbing treatment set to Hz2 (%), the haze change value is expressed by the following equation (z-2). Haze variation (%) = Hz2 - Hz1 ... (z-2) The case where the haze variation of the liquid crystal alignment film is less than 0.5 is evaluated as "excellent (◎)", the case where the haze variation is 0.5 or more but less than 1.0 is evaluated as "good (○)", the case where the haze variation is 1.0 or more but less than 1.5 is evaluated as "acceptable (△)", and the case where it is greater than 1.5 is evaluated as "poor (×)". If the haze variation is less than 1.5 (more preferably less than 1.0, and even more preferably less than 0.5), then it can be said that the film strength is sufficiently high and the abrasion resistance is high, that is, the mechanical properties of the film are good. As a result, the film strength is evaluated as "good (○)" in the above embodiment.

7. Evaluation of Film Strength (Key Resistance Test) The liquid crystal cell manufactured in section 2. was evaluated for its resistance to a key resistance test. The evaluation was conducted as follows: First, the liquid crystal cell was observed under a polarizing microscope with crossed Nicol microscope, and the number of bright spots was counted. Second, the liquid crystal cell was fixed on a mounting plate, and a key bar was moved up and down to repeatedly apply a load to the liquid crystal cell. The load was set to 250 gf, the number of repetitions to 100,000, and the speed to 10 Hz/sec. After pressing the key, the liquid crystal cell was observed again, and the number of bright spots was counted. The film is rated "Excellent" (◎) if the difference in the number of bright spots before and after pressing the button is less than 5; "Good" (○) if the difference is 5 to 10; "Acceptable" (△) if the difference is 10 to 50; and "Unacceptable" (×) if the difference is more than 50. If the difference in the number of bright spots is less than 10 (preferably less than 5), the film can be said to have good mechanical strength for the button. Therefore, in this embodiment, the film strength is rated as "Good" (○).

[Examples 2-15 and Comparative Examples 2 and 3] The liquid crystal alignment agent was prepared in the same manner as in Example 2, except that the composition of the liquid crystal alignment agent was changed as shown in Table 4. Furthermore, using the obtained liquid crystal alignment agent, FFS-type liquid crystal cells were manufactured by the rubbing method, just as in Example 2, and various evaluations were performed. These results are shown in Table 4. Moreover, in Examples 3, 4, 7, and 12-15, two polymers were used as polymer components. In Table 4, the values in the polymer column represent the mixing ratio (parts by mass) of each polymer relative to 100 parts by mass of the total polymer components used in the preparation of the liquid crystal alignment agent, expressed as solid content.

[Table 4] alignment agent Composition Feature Evaluation Polymer 1 Polymer 2 Orientation VHR VHR Reliability Membrane strength and abrasion resistance Membrane strength resistance to key test Kind mass ratio Kind mass ratio Implementation Example 2 AL-1 PAA-2 100 ○ ○ ○ ○ ○ Implementation Example 3 AL-2 PAA-3 30 paa-2 70 ○ ○ ○ ◎ ◎ Implementation Example 4 AL-3 PAA-4 50 paa-3 50 ○ ○ ○ ◎ ◎ Implementation Example 5 AL-4 PAA-5 100 ○ ○ ○ ◎ ◎ Implementation Example 6 AL-5 PAA-6 100 ○ ○ ○ ◎ ◎ Implementation Example 7 AL-6 PAA-7 30 paa-3 70 ○ ○ ○ ◎ ◎ Implementation Example 8 AL-7 PAA-8 100 ○ ○ ○ ◎ ◎ Implementation Example 9 AL-8 PAA-9 100 ○ ○ ○ ○ ○ Implementation Example 10 AL-9 PAA-10 100 ○ ○ ○ ○ ○ Implementation Example 11 AL-10 PAA-11 100 ○ ○ ○ ○ ○ Implementation Example 12 AL-11 PAA-12 30 paa-2 70 ○ ○ ○ ○ ○ Implementation Example 13 AL-12 PAA-13 30 paa-2 70 ○ ○ ○ ◎ ◎ Implementation Example 14 AL-13 PI-1 30 paa-2 70 ○ ○ ○ ◎ ◎ Implementation Example 15 AL-14 PAA-14 70 pi-1 30 ○ ○ ○ ◎ ◎ Comparative example 2 AL-15 paa-1 100 ○ ○ ○ △ × Comparative example 3 AL-16 pi-1 100 ○ ○ △ × ×

As shown in Table 4, Examples 2 to 15, which use liquid crystal alignment agents containing polymer [A], show good or optimal results compared to Comparative Examples 2 and 3, which use liquid crystal alignment agents without polymer [A]. Furthermore, Examples 2 to 15 also exhibit good liquid crystal alignment, initial VHR, and VHR reliability.

[Example 16: Optical FFS Type Liquid Crystal Display Element] 1. Preparation of Liquid Crystal Alignment Agent A solution containing 30 parts by mass of the polymer (PAA-15) obtained in Synthesis Example 15 and a solution containing 70 parts by mass of the polymer (paa-2) obtained in Synthesis Example 18 were mixed and diluted with NMP and BC to prepare a solution with a solvent composition of NMP/BC = 80/20 (mass ratio) and a solid content concentration of 3.5% by mass. The solution was filtered using a 0.2 μm sieve to prepare a liquid crystal alignment agent (AL-17).

2. The manufacturing preparation of the FFS-type liquid crystal display element using photoalignment is the same as that in Example 1, using a first substrate and a second substrate. Then, a liquid crystal alignment agent (AL-17) is coated onto the electrode forming surface of the first substrate and one of the substrate surfaces of the second substrate using a rotary device, and heated (pre-baked) for 1 minute using a hot plate at 80°C. Then, it is dried (post-baked) for 30 minutes in an oven at 230°C where nitrogen replacement has been performed inside the substrate, forming a coating with an average film thickness of 0.1 μm. Photoalignment treatment is performed by irradiating the resulting coating with 1,000 J/ ^m² of ultraviolet light containing a linearly polarized 254 nm bright line from the substrate normal direction using an Hg-Xe lamp. Furthermore, the irradiation amount is a value measured using a photometer with a wavelength of 254 nm as the reference. Next, the photo-aligned coating was heat-treated in a clean oven at 230°C for 30 minutes to form a liquid crystal alignment film. Then, for one of the two substrates with the liquid crystal alignment film, an epoxy resin adhesive containing 3.5 μm diameter aluminum oxide spheres was screen-printed onto the outer edge of the surface with the liquid crystal alignment film. The substrates were then overlapped and pressed together so that the projection direction of the polarization axis onto the substrate surface was antiparallel, and the adhesive was thermo-cured at 150°C for 1 hour. Next, negative liquid crystal (Merck, MLC-6608) was filled between a pair of substrates through the liquid crystal injection port, and then the liquid crystal injection port was sealed with an epoxy adhesive to obtain a liquid crystal cell. Furthermore, to remove flow alignment issues during liquid crystal injection, it was heated to 120°C and then slowly cooled to room temperature. In addition, by varying the post-baking UV irradiation dose within the range of 100 J/ ^m² to 10,000 J/ ^m² , three or more liquid crystal cells with different UV irradiation doses were manufactured. The liquid crystal cell exhibiting the best alignment characteristics (optimal exposure dose) was used for the following evaluations: liquid crystal alignment, initial VHR, VHR reliability, and film strength.

3. Evaluation The liquid crystal cells manufactured in step 2 were evaluated for liquid crystal alignment, initial VHR, and VHR reliability using the same method as in Example 2. Additionally, the film strength was evaluated using a liquid crystal alignment agent (AL-17) in the same manner as in Example 2. The evaluation results are shown in Table 5.

[Examples 17-23, Comparative Examples 4, and Comparative Examples 5] The liquid crystal alignment agent was prepared in the same manner as in Example 16, except that the composition of the liquid crystal alignment agent was changed as shown in Table 5. Furthermore, using the obtained liquid crystal alignment agent, FFS-type liquid crystal cells were manufactured by photoalignment method in the same manner as in Example 16, and various evaluations were performed. The results are shown in Table 5. In addition, in Examples 23 and Comparative Examples 5, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenylmethane (designated as compound (N-1)) was formulated as an additive component along with the polymer component. In Table 5, the values in the "Polymers" column represent the proportion (parts by mass) of each polymer relative to 100 parts by mass of the total solid components (polymer components and additive components) used in the preparation of the liquid crystal alignment agent.

[Table 5] alignment agent Composition Feature Evaluation Polymer 1 Polymer 2 Additives Orientation VHR VHR Reliability Membrane strength and abrasion resistance Membrane strength resistance to key test Kind mass ratio Kind mass ratio Kind mass ratio Implementation Example 16 AL-17 PAA-15 30 paa-2 70 ○ ○ ○ ◎ ◎ Implementation Example 17 AL-18 PAA-16 90 pi-2 10 ○ ○ ○ ◎ ◎ Implementation Example 18 AL-19 PAA-17 80 paa-4 20 ○ ○ ○ ○ ○ Implementation Example 19 AL-20 PAA-18 20 paa-3 80 ○ ○ ○ ○ ○ Implementation Example 20 AL-21 PAA-19 80 paa-4 20 ○ ○ ○ ○ ○ Implementation Example 21 AL-22 PAA-20 20 paa-3 80 ○ ○ ○ ○ ○ Implementation Example 22 AL-23 PI-2 10 paa-3 90 ○ ○ ○ ◎ ◎ Implementation Example 23 AL-24 PI-2 5 paa-3 90 N-1 5 △ ○ ○ ◎ ◎ Comparative example 4 AL-25 paa-4 30 paa-2 70 ○ ○ ○ △ × Comparative example 5 AL-26 pi-2 5 paa-3 90 N-1 5 △ ○ △ ○ ×

As shown in Table 5, Examples 16 to 23, which use liquid crystal alignment agents containing polymer [A], show good or optimal results compared to Comparative Examples 4 and 5, which use liquid crystal alignment agents without polymer [A], achieving a balance between liquid crystal alignment, initial VHR, and VHR reliability.

[Example 24: PSA-type Liquid Crystal Display Element] 1. Preparation of Liquid Crystal Alignment Agent A solution containing 5 parts by mass of the polymer (PSQ-1) obtained in Synthesis Example 31 and a solution containing 95 parts by mass of the polymer (PI-3) obtained in Synthesis Example 27 were mixed and diluted with NMP and BC to prepare a solution with a solvent composition of NMP/BC = 50/50 (mass ratio) and a solid content concentration of 3.5% by mass. The solution was filtered using a 0.2 μm sieve to prepare a liquid crystal alignment agent (AL-27).

2. Preparation of the liquid crystal composition: 10 g of a nematic liquid crystal (Merck, MLC-6608) was mixed with 5% by mass of a liquid crystal compound represented by formula (L1-1) and 0.3% by mass of a photopolymerizable compound represented by formula (L2-1) to obtain the liquid crystal composition LC1. [Chemical 35]

3. In the manufacture of PSA-type liquid crystal display elements, a rotary tool is used to coat the prepared liquid crystal alignment agent (AL-27) onto the transparent electrode surface of a glass substrate containing an ITO film and transparent electrodes. After pre-baking on a hot plate at 80°C for 1 minute, the solvent is removed by heating at 200°C for 1 hour in a nitrogen-filled oven, thereby forming a coating (liquid crystal alignment film) with a thickness of 0.08 μm. The coating is then rubbed using a friction machine with rollers wound with rayon cloth at a roller speed of 400 rpm, a stage movement speed of 3 cm/s, and a bristle indentation length of 0.1 mm. Then, the substrate is ultrasonically cleaned in ultrapure water for 1 minute, followed by drying in a clean oven at 100°C for 10 minutes, thereby obtaining a substrate with a liquid crystal alignment film. This process is repeated to obtain a pair (two) substrates with liquid crystal alignment films. Furthermore, the friction treatment is a weak friction treatment performed to control liquid crystal collapse and to facilitate alignment separation using a simple method. An epoxy resin adhesive containing 3.5 μm diameter alumina spheres is screen-printed onto the outer periphery of the liquid crystal alignment film side of one substrate. The liquid crystal alignment film sides of the pair of substrates are then overlapped and pressed together, and the adhesive is thermo-cured at 150°C for 1 hour. Next, after filling the gap between the liquid crystal injection port and the substrate with the liquid crystal assembly LC1, the liquid crystal injection port is sealed with an epoxy adhesive. To remove flow alignment issues during liquid crystal injection, it is heated at 150°C for 10 minutes and then slowly cooled to room temperature. Then, an AC 10V at a frequency of 60 Hz is applied between the electrodes of the resulting liquid crystal cell, and while the liquid crystal is driven, it is irradiated with ultraviolet light at a dose of 50,000 J/ ^m² using an ultraviolet irradiation device with a metal halide lamp as the light source. Furthermore, the irradiation dose is measured using a photometer with a wavelength of 365 nm as the reference. Thus, a PSA-type liquid crystal cell is manufactured.

4. Evaluation The liquid crystal cells manufactured in step 3 were evaluated using the same method as in Example 2, focusing on liquid crystal alignment, initial VHR, VHR reliability, and film strength. The evaluation results are shown in Table 6.

[Comparative Example 6] The liquid crystal alignment agent was prepared in the same manner as in Example 24, except that the composition of the liquid crystal alignment agent was changed as shown in Table 6. Furthermore, using the obtained liquid crystal alignment agent, PSA-type liquid crystal cells were manufactured in the same manner as in Example 24, and various evaluations were performed. The evaluation results are shown in Table 7. In Table 7, the values in the polymer column represent the mixing ratio (parts by mass) of each polymer relative to 100 parts by mass of the total polymer components used in the preparation of the liquid crystal alignment agent, expressed as solid components.

[Table 6] alignment agent Orientation agent composition Evaluation of properties as an orientation agent Polymer 1 Polymer 2 Orientation VHR VHR Reliability Membrane strength and abrasion resistance Membrane strength resistance to key test Kind mass ratio Kind mass ratio Implementation Example 24 AL-27 PI-3 95 PSQ-1 5 ○ ○ ○ ◎ ◎ Comparative example 6 AL-28 pi-3 95 PSQ-1 5 ○ ○ △ △ ×

As shown in Table 6, in Example 24 using a liquid crystal alignment agent containing polymer [A], the liquid crystal alignment, initial VHR, and VHR reliability were all rated as good, and the film strength was rated as optimal. In contrast, in Comparative Example 6 using a liquid crystal alignment agent without polymer [A], the film strength (abrasion resistance) was rated as "acceptable," and the film strength (button resistance) was rated as "poor."

[Example 25: Optical VA-type Liquid Crystal Display Element] 1. Preparation of Liquid Crystal Alignment Agent A solution containing 30 parts by mass of the polymer (MI-1) obtained in Synthesis Example 32 and a solution containing 70 parts by mass of the polymer (PAA-14) obtained in Synthesis Example 14 were mixed and diluted with NMP and BC to prepare a solution with a solvent composition of NMP/BC = 80/20 (mass ratio) and a solid content concentration of 3.5% by mass. The solution was filtered using a 0.2 μm sieve to prepare a liquid crystal alignment agent (AL-29).

2. Fabrication of the VA-type liquid crystal display element: A rotating device is used to coat the prepared liquid crystal alignment agent (AL-29) onto the transparent electrode surface of a glass substrate containing an ITO film with transparent electrodes, followed by pre-baking on a hot plate at 80°C for 1 minute. Then, in an oven where nitrogen replacement has been performed, heating at 230°C for 1 hour forms a coating with a thickness of 0.1 μm. Next, using an Hg-Xe lamp and a Gran-Taylor prism, polarized ultraviolet light containing a bright line of 313 nm (1000 J/ ^m² ) is irradiated onto the coating surface from a direction inclined at 40° from the substrate normal to impart liquid crystal alignment capability. The same operation is repeated to fabricate a pair (two) of substrates with liquid crystal alignment films. An epoxy resin adhesive containing 3.5 μm diameter alumina spheres was screen-printed onto the outer periphery of the surface of one substrate with a liquid crystal alignment film. The liquid crystal alignment films of a pair of substrates were then faced together, and pressed together with the projection directions of the ultraviolet light axes of each substrate onto the substrate surface antiparallel. The adhesive was then thermosetting at 150°C for 1 hour. Next, negative liquid crystal (Merck, MLC-6608) 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 adhesive. Furthermore, to remove flow alignment issues during liquid crystal injection, the liquid crystal was heated to 130°C and then slowly cooled to room temperature.

3. Evaluation The liquid crystal cells manufactured in step 2 were evaluated using the same method as in Example 2, focusing on liquid crystal alignment, initial VHR, VHR reliability, and film strength. The evaluation results are shown in Table 7.

[Comparative Example 7] The liquid crystal alignment agent was prepared in the same manner as in Example 25, except that the composition of the liquid crystal alignment agent was changed as shown in Table 7. Furthermore, using the obtained liquid crystal alignment agent, optical VA-type liquid crystal cells were manufactured in the same manner as in Example 25, and various evaluations were performed. These results are shown in Table 7. In Table 7, the values in the polymer column represent the mixing ratio (parts by mass) of each polymer relative to 100 parts by mass of the total polymer components used in the preparation of the liquid crystal alignment agent, based on the solid content.

[Table 7] alignment agent Orientation agent composition Evaluation of properties as an orientation agent Polymer 1 Polymer 2 Orientation VHR VHR Reliability Membrane strength and abrasion resistance Membrane strength resistance to key test Kind mass ratio Kind mass ratio Implementation Example 25 AL-29 PAA-14 70 MI-1 30 ○ ○ ○ ◎ ◎ Comparative example 7 AL-30 paa-1 70 MI-1 30 ○ ○ ○ △ ×

As shown in Table 7, in Example 25 using a liquid crystal alignment agent containing polymer [A], the liquid crystal alignment, initial VHR, and VHR reliability were all rated as good, and the film strength was rated as optimal. In contrast, in Comparative Example 7 using a liquid crystal alignment agent without polymer [A], the film strength (abrasion resistance) was rated as "acceptable," and the film strength (button resistance) was rated as "poor."

Based on the above results, it is clear that: liquid crystal aligners containing polymers having a partial structure (a) in the main chain can not only produce liquid crystal elements with good liquid crystal alignment, high voltage retention and excellent reliability, but also achieve high hardened film strength.

Claims (14)

A liquid crystal alignment agent comprising a polymer [A] having a partial structure (a) represented by formula (1) on the main chain, [Chemical 1] (In formula (1), ^R1 and ^R2 are independently divalent groups formed by bonding -C( ^R5 )( ^R6 )-, -O-, -S-, -CO-, -COO-, -NR7-, -NR7- ^NR8- , ^-NR7 -CO-O-, ^-NR7 -CO- ^NR8- , aromatic hydrocarbon rings, aromatic heterocycles or ^nitrogen -containing non-aromatic heterocycles with the carbonyl group in formula (1); ^{R3 and R4} are independently hydrogen atoms, halogen atoms or alkyl groups having 1 to 3 carbon atoms, or represent a ring structure formed by the combination of ^R3 and ^R4 together with the carbon atoms bonded to ^R3 and ^R4 ; ^R5 and R ^R6 is independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms; ^R7 and ^R8 are independently hydrogen atoms or monovalent organic groups; "*" indicates a bond. The liquid crystal alignment agent as claimed in claim 1, wherein the polymer [A] comprises a structural unit derived from a diamine having said partial structure (a). The liquid crystal alignment agent as described in claim 2, wherein the diamine is a compound represented by the following formula (2), [Chemical 2] (In formula (2), ^A1 and ^A2 are respectively a single bond, a divalent alicyclic group or a divalent aromatic cyclic group; m1 is an integer from 1 to 3; ^R1 , ^R2 , ^R3 and ^R4 have the same meaning as in formula (1); when m1 is 2 or 3, multiple ^R1 to ^R4 are the same or different from each other). The liquid crystal alignment agent as claimed in claim 1, wherein the polymer [A] comprises a structural unit derived from a tetracarboxylic acid derivative having said partial structure (a). The liquid crystal alignment agent as described in claim 4, wherein the tetracarboxylic acid derivative is at least one selected from the group consisting of compounds represented by formula (3) and compounds represented by formula (4), [Chemical 3] (In equations (3) and (4), ^A3 and ^A4 are trivalent aromatic cycloalloys or aliphatic cycloalloys, respectively; m2 is an integer from 1 to 3; n1 and n2 are integers from 1 to 3, respectively; ^R1 , ^R2 , ^R3 and ^R4 have the same meaning as in equation (1); when m2 is 2 or 3, multiple ^R1 to ^R4 are the same or different from each other). The liquid crystal alignment agent as claimed in claim 1, wherein the polymer [A] is at least one selected from the group consisting of polyamide, polyamide ester and polyimide. The liquid crystal alignment agent as described in claim 6, wherein the polymer [A] comprises a structural unit derived from an alicyclic tetracarboxylic dianhydride. The liquid crystal alignment agent as described in claim 1 further comprises a polymer [Q] that does not have said partial structure (a). A liquid crystal alignment film is formed by means of a liquid crystal alignment agent as described in any one of claims 1 to 8. A liquid crystal element comprising a liquid crystal alignment film as described in claim 9. A polyamide, polyamide ester, and polyimide have a partial structure in the backbone represented by the following formula (1), [Chem. 4] (In formula (1), ^R1 and ^R2 are independently divalent groups formed by bonding -C( ^R5 )( ^R6 )-, -O-, -S-, -CO-, -COO-, -NR7-, -NR7- ^NR8- , ^-NR7 -CO-O-, ^-NR7 -CO- ^NR8- , aromatic hydrocarbon rings, aromatic heterocycles or ^nitrogen -containing non-aromatic heterocycles with the carbonyl group in formula (1); ^{R3 and R4} are independently hydrogen atoms, halogen atoms or alkyl groups having 1 to 3 carbon atoms, or represent a ring structure formed by the combination of ^R3 and ^R4 together with the carbon atoms bonded to ^R3 and ^R4 ; ^R5 and R ^R6 is independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an alkoxy group having 1 to 8 carbon atoms; ^R7 and ^R8 are independently hydrogen atoms or monovalent organic groups; "*" indicates a bond. A method for producing a diamine, wherein a compound represented by formula (5) is used in a raw material to produce a diamine represented by formula (2), [Chem. 5] (In equation (5), ^R9 is a single bond or a divalent organic group) [Chemistry 6] In formula (2), ^A1 and ^A2 are independently monovalent, divalent alicyclic, or divalent aromatic cyclic groups, respectively; ^R1 and ^R2 are independently divalent groups formed by bonding -C( ^R5 )( ^R6 )-, -O-, -S-, -CO-, -COO-, -NR7-, -NR7- ^NR8- , ^{-NR7 -} CO-O-, ^-NR7 -CO- ^NR8- , aromatic hydrocarbon rings, aromatic heterocycles, or ^nitrogen -containing non-aromatic heterocycles with the carbonyl group in formula (2); ^R3 and ^R4 are independently hydrogen atoms, halogen atoms, or alkyl groups having 1 to 3 carbon atoms, or represent the carbon atom and ^R3 bonded to ^R4 by R3 ^. The ring structure is formed by ^{the four} bonded carbon atoms; ^R5 and ^R6 are independently hydrogen atoms, halogen atoms, alkyl groups with 1 to 8 carbon atoms, alkenyl groups with 2 to 8 carbon atoms, or alkoxy groups with 1 to 8 carbon atoms, respectively; ^R7 and ^R8 are independently hydrogen atoms or monovalent organic groups, respectively; m1 is an integer from 1 to 3; when m1 is 2 or 3, multiple ^R1 to ^R4 are the same or different from each other. A method for producing a tetracarboxylic dianhydride, wherein a compound represented by formula (5) is used in a feedstock to produce a tetracarboxylic dianhydride represented by formulas (3) and (4), [Chemistry 7] (In equation (5), ^R9 is a single bond or a divalent organic group) [Chemistry 8] In formulas (3) and (4), ^A3 and ^A4 are each independently trivalent aromatic cycloalkanes or aliphatic cycloalkanes; ^R1 and ^R2 are each independently divalent groups bonded to the carbonyl group in formulas (3) and ( ⁴ ) using -C(R5)( ^R6 )-, -O-, -S-, -CO-, ^-COO- , -NR7-, ^-NR7 - ^NR8- , ^-NR7 -CO-O-, ^-NR7 -CO- ^NR8- , aromatic hydrocarbon rings, aromatic heterocycles or nitrogen-containing non-aromatic heterocycles; ^R3 and ^R4 are each independently hydrogen atoms, halogen atoms or alkyl groups having 1 to 3 carbon atoms, or represent the carbon atom and R bonded to ^R3 by ^R3 and ^R4. The ring structure is formed by ^{the four} bonded carbon atoms; ^R5 and ^R6 are independently hydrogen atoms, halogen atoms, alkyl groups with 1 to 8 carbon atoms, alkenyl groups with 2 to 8 carbon atoms, or alkoxy groups with 1 to 8 carbon atoms, respectively; ^R7 and ^R8 are independently hydrogen atoms or monovalent organic groups, respectively; m2 is an integer from 1 to 3; n1 and n2 are independently integers from 1 to 3; when m2 is 2 or 3, multiple ^R1 to ^R4 are the same or different from each other. A method for manufacturing a polymer, comprising polymerizing monomers of at least one compound selected from the group consisting of a diamine obtained by the method of claim 12 and a tetracarboxylic dianhydride obtained by the method of claim 13, to produce polyamide, polyamide ester and polyimide as described in claim 11.